Repeatability and reproducibility of the ISO/TS 19700 steady state tube furnace - Purser, J.A.; Purser, D.A.; Stec, A.A.; Moffatt, C.; Hull, T.R.; Su, J.Z.; Bijloos, M.; Blomqvist, P. (Fire Safety Journal, 2013)
The ISO/TS 19700 steady state tube furnace is designed to measure the yields of combustion products, and in particular toxic combustion products, under a range of different specified decomposition conditions occurring in full-scale compartment fires. In order to establish the repeatability and reproducibility of the method, a Round Robin inter-laboratory study and statistical analysis has been carried out involving three laboratories. Pre-existing data from a fourth laboratory have also been considered where appropriate. Samples of different polymers (PMMA, LDPE, PA6.6 and rigid PVC) were tested under two fire conditions: well-ventilated flaming at 650 °C and post-flashover under-ventilated flaming at 825 °C, with each laboratory performing three replicate runs on each polymer under each condition. The results showed good agreement between laboratories and against calculated stoichiometric maxima, demonstrating satisfactory levels of repeatability and reproducibility for key combustion gases. These included O2 consumption, and the yields of CO2, CO, HCN and HCl. A number of amendments to the standard have been recommended as a result of minor procedural issues arising during preliminary work. © 2012 Elsevier Ltd.
Keywords: ISO TS 19700; Repeatability; Reproducibilities; Toxic; Tube furnaces; Carbon dioxide; Furnaces; Polymers; Toxicity; Tubes (components); Laboratories

One- and two-magnon and exciton Raman scattering in antiferromagnetic CoF2: Experiment and theory - Meloche, E.; Cottam, M.G.; Lockwood, D.J. (Journal of the Korean Physical Society, 2013)
Experimental data are reported for the temperature and polarization dependence of the oneand two-magnon Raman light scattering in the rutile-structure antiferromagnet CoF2. The correspondingn Stokes and anti-Stokes Raman spectra are measured, emphasizing the temperature and polarization variations of the one-magnon frequency, line width, and integrated intensity. A Green's function method is employed to derive the excitation energies and their intensities over a broad range of temperatures (below the Néel temperature = 38 K) for a spin S = 3/2 anisotropic antiferromagnet with strong spin-orbit coupling. The exchange terms are analyzed using the random-phase approximation while single-ion anisotropy terms are treated exactly by generating a closed set of coupled Green's function equations. Good overall agreement between theory and experiment is obtained. © 2013 The Korean Physical Society.

Small-scale structure in fluid cholesterol-lipid bilayers - Rheinstädter, M.C.; Mouritsen, O.G. (Current Opinion in Colloid and Interface Science, 2013)
Cholesterol is the single most abundant molecule in animal plasma membranes, in the range of 20-30. mol%, where it is known to modulate the lipid-bilayer component of the membrane and lead to increased mechanical stability, lower permeability, larger thickness, and a distinct lateral organization. The phase equilibria of membranes with cholesterol and the associated large- and small-scale structure have turned out to be a particularly elusive problem. With the proposal that lipid domains and so-called 'rafts', characterized by high local levels of cholesterol in a liquid-ordered phase, are important for a wide range of cellular functions, an understanding and a quantitative assessment of the nature of these cholesterol-induced structures and their types of ordering have become urgent. Recent progress in neutron diffraction studies of lipid-cholesterol model membranes has now revealed details of the lateral ordering, and combined with earlier molecular model studies a picture emerges of the membrane as a locally structured liquid with small ordered 'domains' of a highly dynamic nature. © 2013 Elsevier Ltd.
Keywords: Correlation function; Liquid-ordered phase; Molecular modeling studies; Neutron diffraction studies; Quantitative assessments; Raft; Small-scale structures; Structured liquids; Cell membranes; Computer simulation; Lipid bilayers; Neutron diffraction; Neutron scattering; Cholesterol; cholesterol; lipid; cell function; cell membrane; chemical structure; computer simulation; controlled study; lipid bilayer; lipid raft; membrane permeability; molecular dynamics; molecular model; neutron diffraction; neutron scattering; protein domain; review; small scale structure; thickness

Solid state complex chemistry: Formation, structure, and properties of homoleptic tetracyanamidogermanates RbRE[Ge(CN2)4] (RE = La, Pr, Nd, Gd) - Kalmutzki, M.; Enseling, D.; Wren, J.E.C.; Kroeker, S.; Terskikh, V.V.; Jüstel, T.; Meyer, H.-J. (Inorganic Chemistry, 2013)
Tetracyanamidometallates with the general formula RbRE[T(CN 2)4] (RE = La, Pr, Nd, Gd; T = Si, Ge) were prepared by solid state metathesis reactions starting from stoichiometric mixtures of RECl3, A2[TF6], and Li2(CN 2). Reactions were studied by differential thermal analysis that showed ignition temperatures between 360 and 390 C for the formation of RbGd[T(CN2)4] with T = Si and Ge. The powder diffraction patterns of RbRE[Ge(CN2)4] were indexed isotypically to the already known RbRE[Si(CN2)4] compound. IR spectra of RbLa[Ge(CN2)4] were measured and compared with those of RbLa[Si(CN2)4]. 73Ge, 87Rb, and 139La solid state NMR measurements and density functional theory calculations were used to verify the novel homoleptic [Ge(CN2) 4]4- ion. Luminescence properties of Eu3+, Ce3+, and Tb3+ doped samples are reported. © 2013 American Chemical Society.

Improving the strength and corrosion resistance of 316L stainless steel for biomedical applications using cold spray - Al-Mangour, B.; Mongrain, R.; Irissou, E.; Yue, S. (Surface and Coatings Technology, 2013)
Stainless steel 316L mixed with cobalt chromium alloy L605 powders has been cold sprayed onto mild steel substrate. As spraying Co-Cr alone is difficult, three different proportions (by volume of Co-Cr, 25%, 33.3% and 50%) were used in this study. Analysis and characterization of sprayed depositions were performed through scanning electron microscopy, electron backscatter diffraction, microhardness, and tensile tests at room temperature. The porosity of the coating was low for both the 25% and 33.3% coating (about 0.9-1.5%). However, the 50% coating had a much poorer deposition rate leading to a much thinner coating using the same coating parameters; the porosity was much higher (about 4.5%). The ductility of the annealed 25% and 33.3% specimens reached approximately 20% and 18% respectively after annealing, but the 50% specimen was too thin to be tested. The corrosion behavior was evaluated using potentiodynamic polarization tests carried at Hank's solution as an electrolyte. It was found that corrosion resistances of the metal-metal mixture were higher than that of pure stainless steel. © 2012 Elsevier B.V.
Keywords: 316 L stainless steel; Analysis and characterization; Biomedical applications; Coating parameters; Cobalt-chromium alloys; Cold gas dynamic spray; Cold spray; Corrosion behavior; Electron back scatter diffraction; Hank's solution; Mild steel substrates; Potentiodynamic polarization tests; Room temperature; Stainless steel 316L; Stent; Tensile tests; Thinner coatings; Carbon steel; Chromium; Chromium alloys; Coatings; Cobalt; Diffusion; Ductility; Medical applications; Scanning electron microscopy; Stainless steel; Tensile testing; Corrosion resistance

Crack detection using induction thermography during high temperature testing - Genest, M.; Dudzinski, D.C.; Dawag, L.; Kersey, R.K. (SPIE - International Society for Optical Engineering. Proceedings, 2013)
Thermo-mechanical fatigue (TMF) tests and strain to crack (SC) tests at elevated temperature are important aspects to the total fatigue life for many engineering applications. During a TMF test, crack inspections are commonly done in a disruptive manner using an acetate replication method; and post-test crack evaluations are done using both optical and scanning electronic microscopy methods. Similarly, inspections during a typical SC test are also performed in a disruptive manner. This paper demonstrates that infrared imaging can be used as an in-situ inspection approach to detect crack during TMF and SC tests at high temperature. It is also demonstrated that this technique allows for the reduction or elimination of the need for downtime that is typically required for disruptive inspection. The results obtained by induction thermography are compared to those obtained via traditional methods and post-test evaluation. The induction thermography inspections were carried out at several temperatures and showed that the temperature used during the test does not influence the crack detection capability. It is demonstrated that induction thermography can detect cracks smaller than 500 μm and has potential for monitoring and generating a crack growth curve. © 2013 SPIE.
Keywords: Crack growth curves; Detection capability; Elevated temperature; Engineering applications; Replication method; Scanning electronic microscopy; Thermo mechanical fatigues (TMF); Total fatigue lives; Crack detection; Fatigue of materials; Induction heating; Infrared devices; Infrared radiation; Inspection; Thermography (imaging); Thermography (temperature measurement); Cracks

Linkage between bacterial and fungal rhizosphere communities in hydrocarbon-contaminated soils is related to plant phylogeny - Bell, T.H.; El-Din Hassan, S.; Lauron-Moreau, A.; Al-Otaibi, F.; Hijri, M.; Yergeau, E.; St-Arnaud, M. (ISME Journal, 2013)
Phytoremediation is an attractive alternative to excavating and chemically treating contaminated soils. Certain plants can directly bioremediate by sequestering and/or transforming pollutants, but plants may also enhance bioremediation by promoting contaminant-degrading microorganisms in soils. In this study, we used high-throughput sequencing of bacterial 16S rRNA genes and the fungal internal transcribed spacer (ITS) region to compare the community composition of 66 soil samples from the rhizosphere of planted willows (Salix spp.) and six unplanted control samples at the site of a former petrochemical plant. The Bray-Curtis distance between bacterial communities across willow cultivars was significantly correlated with the distance between fungal communities in uncontaminated and moderately contaminated soils but not in highly contaminated (HC) soils (>2000 mg kg-1 hydrocarbons). The mean dissimilarity between fungal, but not bacterial, communities from the rhizosphere of different cultivars increased substantially in the HC blocks. This divergence was partly related to high fungal sensitivity to hydrocarbon contaminants, as demonstrated by reduced Shannon diversity, but also to a stronger influence of willows on fungal communities. Abundance of the fungal class Pezizomycetes in HC soils was directly related to willow phylogeny, with Pezizomycetes dominating the rhizosphere of a monophyletic cluster of cultivars, while remaining in low relative abundance in other soils. This has implications for plant selection in phytoremediation, as fungal associations may affect the health of introduced plants and the success of co-inoculated microbial strains. An integrated understanding of the relationships between fungi, bacteria and plants will enable the design of treatments that specifically promote effective bioremediating communities.The ISME Journal advance online publication, 29 August 2013; doi:10.1038/ismej.2013.149.

Synthesims of 7-oxabicyclo[2.2.1]heptanes and 8-oxabicyclo[3.2.1]octanes from C-glycosides via an intramolecular cyclization - Zou, W.; Vembaiyan, K. (Journal of Organic Chemistry, 2013)
A simple and effective method for the synthesis of 7-oxabicyclo[2.2.1] heptanes and 8-oxabicyclo[3.2.1]octanes from acetonyl C-glycoside substrates is described, which involves an intramolecular cyclization reaction through a nucleophilic substitution at C-5 or C-6 of C-glycosides by a 2′-enamine intermediate formed in the presence of pyrrolidine. Because anomeric epimerization occurs under these conditions, C-glycoside substrates with either anomeric configuration were converted to the same product(s) in same stereoselectivity and similar chemical yield. © 2013 American Chemical Society.
Keywords: Anomeric configuration; C-glycosides; Chemical yields; Enamine intermediates; Epimerization; Intramolecular cyclizations; Nucleophilic substitutions; Pyrrolidines; Cyclization; Heptane; Stereoselectivity; Sugars; 7 oxabicyclo [2 2 1] heptane; 8 oxabicyclo [3 2 1]octane; glycoside; heptane; octane; pyrrolidine derivative; unclassified drug; bicyclo compound; C glycoside; C-glycoside; cycloheptane derivative; cyclooctane derivative; monosaccharide; article; chemical reaction; chemical structure; cyclization; epimerization; nucleophilicity; stereochemistry; synthesis; chemistry; cyclization; stereoisomerism; Bicyclo Compounds; Cyclization; Cycloheptanes; Cyclooctanes; Molecular Structure; Monosaccharides; Stereoisomerism

In vivo neutralization of α-Cobratoxin with high-affinity llama single-domain antibodies (VHHs) and a VHH-Fc antibody - Richard, G.; Meyers, A.J.; McLean, M.D.; Arbabi-Ghahroudi, M.; MacKenzie, R.; Hall, J.C. (PLoS ONE, 2013)
Small recombinant antibody fragments (e.g. scFvs and VHHs), which are highly tissue permeable, are being investigated for antivenom production as conventional antivenoms consisting of IgG or F(ab')2 antibody fragments do not effectively neutralize venom toxins located in deep tissues. However, antivenoms composed entirely of small antibody fragments may have poor therapeutic efficacy due to their short serum half-lives. To increase serum persistence and maintain tissue penetration, we prepared low and high molecular mass antivenom antibodies. Four llama VHHs were isolated from an immune VHH-displayed phage library and were shown to have high affinity, in the low nM range, for α-cobratoxin (α-Cbtx), the most lethal component of Naja kaouthia venom. Subsequently, our highest affinity VHH (C2) was fused to a human Fc fragment to create a VHH2-Fc antibody that would offer prolonged serum persistence. After in planta (Nicotiana benthamiana) expression and purification, we show that our VHH2-Fc antibody retained high affinity binding to α-Cbtx. Mouse α-Cbtx challenge studies showed that our highest affinity VHHs (C2 and C20) and the VHH2-Fc antibody effectively neutralized lethality induced by α-Cbtx at an antibody:toxin molar ratio as low as ca. 0.75×:1. Further research towards the development of an antivenom therapeutic involving these anti-α-Cbtx VHHs and VHH2-Fc antibody molecules should involve testing them as a combination, to determine whether they maintain tissue penetration capability and low immunogenicity, and whether they exhibit improved serum persistence and therapeutic efficacy. © 2013 Richard et al.
Keywords: antibody; cobrotoxin; single variable domain antibody; single variable domain Fc antibody; snake venom antiserum; unclassified drug; animal cell; animal experiment; animal model; antibody affinity; article; controlled study; drug efficacy; drug penetration; envenomation; female; humoral immunity; in vivo study; lethality; male; molecular weight; mouse; Nicotiana benthamiana; nonhuman; protein expression; protein purification

A Herschel * and APEX census of the reddest sources in Orion: Searching for the youngest protostars - Stutz, A. M.; Tobin, J. J.; Stanke, T.; Megeath, S. T.; Fischer, W. J.; Robitaille, T.; Henning, T.; Ali, B.; di Francesco, J.; Furlan, E.; Hartmann, L.; Osorio, M.; et al. (The Astrophysical Journal, 2013)
We perform a census of the reddest, and potentially youngest, protostars in the Orion molecular clouds using data obtained with the PACS instrument on board the Herschel Space Observatory and the LABOCA and SABOCA instruments on APEX as part of the Herschel Orion Protostar Survey (HOPS). A total of 55 new protostar candidates are detected at 70 μm and 160 μm that are either too faint (m24 > 7 mag) to be reliably classified as protostars or undetected in the Spitzer/MIPS 24 μm band. We find that the 11 reddest protostar candidates with log λFλ70/λF λ24 > 1.65 are free of contamination and can thus be reliably explained as protostars. The remaining 44 sources have less extreme 70/24 colors, fainter 70 μm fluxes, and higher levels of contamination. Taking the previously known sample of Spitzer protostars and the new sample together, we find 18 sources that have log λFλ70/ λFλ24 > 1.65; we name these sources "PACS Bright Red sources," or PBRs. Our analysis reveals that the PBR sample is composed of Class 0 like sources characterized by very red spectral energy distributions (SEDs; Tbol < 45 K) and large values of sub-millimeter fluxes (Lsmm/Lbol > 0.6%). Modified blackbody fits to the SEDs provide lower limits to the envelope masses of 0.2-2 M⊙ and luminosities of 0.7-10 L⊙. Based on these properties, and a comparison of the SEDs with radiative transfer models of protostars, we conclude that the PBRs are most likely extreme Class 0 objects distinguished by higher than typical envelope densities and hence, high mass infall rates. © 2013. The American Astronomical Society. All rights reserved.
Keywords: ISM clouds; Star formation; Low-mass stars; Protostars

Surface-enhanced Raman and optical scattering in coupled plasmonic nanoclusters - Tay, Li-Lin; Hulse, John (Journal of Modern Optics, 2013)
Optical excitation of small Au nanoparticle (NP) clusters of appropriate wavelength is known to generate intense electromagnetic fields localized uniquely at NP junction sites within the nanoclusters. These intense and localized field hot-sites can induce intense surface-enhanced Raman scattering (SERS) of molecules residing at the junction hot-sites. In this paper, we present a series of electromagnetic simulations, experimental SERS and extinction data obtained from small self-assembled Au NP clusters coated to saturation with a Raman reporter molecule. Our experimental data show that the SERS enhancement factor remains relatively constant despite the heterogeneity of the nanocluster and this is supported by the simulation results. Furthermore, our simulation results show significant variations in the localized electric field intensities of the junction hot-sites in different nanocluster geometries. This explains the observation that increasing the number of hot-sites does not necessarily result in a higher SERS enhancement factor.
Keywords: Plasmonics; surface-enhanced Raman scattering; gold nanoparticle; nanocluster structure; hot-spot

Quantitative proteomic investigation employing stable isotope labeling by peptide dimethylation on proteins of strawberry fruit at different ripening stages - Li, L.; Song, J.; Kalt, W.; Forney, C.; Tsao, R.; Pinto, D.; Chisholm, K.; Campbell, L.; Fillmore, S.; Li, X. (Journal of Proteomics, 2013)
A quantitative proteomic investigation of strawberry fruit ripening employing stable isotope labeling by peptide dimethylation was conducted on 'Mira' and 'Honeoye' strawberry fruit. Postharvest physiological quality indices, including volatile production, total phenolics, total anthocyanins, antioxidant capacity, soluble solids and titratable acidity, were also characterized in white, pink and red fruit. More than 892 and 848 proteins were identified and quantified in the 'Mira' and 'Honeoye' fruit, respectively, using at least two peptides for each protein identification. Using the normalized ratio of protein abundance changes, proteins that changed two-fold or more were identified as proteins that are up- or down-regulated during fruit ripening. Among the quantified proteins, 111 proteins were common to both cultivars and represented five significant clusters based on quantitative changes. Among the up-regulated proteins were proteins involved in metabolic pathways including flavonoid/anthocyanin biosynthesis, volatile biosynthesis, antioxidant metabolism, stress responses and allergen formation. Proteins that decreased during fruit ripening were found to be responsible for methionine metabolism, antioxidant-redox, energy metabolism and protein synthesis. Our results show that strawberry ripening is a highly complex system involving multi-physiological processes made possible through changes in protein expression. This study provides new insights on the regulation of proteins during strawberry fruit ripening that lay the foundation for further targeted studies. Biological significance: Research on the postharvest physiology and biochemistry of strawberry fruit as a model of non-climacteric fruit ripening has been conducted for many years. However, the mechanism(s) for the initiation and metabolic regulation of non-climacteric fruit ripening remains unknown. Little information on strawberry fruit ripening is available at the proteome level. This paper is the first report of a quantitative proteomic investigation of strawberry fruit ripening employing stable isotope labeling by peptide dimethylation. Postharvest physiological quality indices, including volatile production, total phenolics, total anthocyanins, antioxidant capacity, soluble solids and titratable acidity, were also characterized in ripening fruit. Significant biological changes associated with ripening were revealed and proteins that change significantly under these conditions were identified. Therefore, our study links the biological events of strawberry fruit ripening with proteomic information and provides insights into possible mechanisms of regulation. Proteins that changed during ripening were analyzed through function analysis, which provides new insights into metabolic changes occurring during ripening. Findings from this paper not only provide proteome information on fruit ripening, but also pave the way for further quantitative studies using SMR to investigate certain proteins and pathways involved in fruit ripening. © 2013.
Keywords: aconitate hydratase; actin; acyltransferase; adenosine kinase; allergen; aquaporin; ascorbate peroxidase; aspartic proteinase; carbonate dehydratase; cystatin; erbium; heat shock protein 70; lipid transfer protein; methionine synthase; methyltransferase; nucleoside diphosphate kinase; oligomycin; oxidoreductase; oxygenase; pectinesterase; peptide; phosphoglucomutase; phosphoglycerate dehydrogenase; prohibitin; protein; pyruvate decarboxylase; stable isotope; transaldolase; uridine diphosphate; uridine diphosphate glucose; article; biosynthesis; controlled study; energy metabolism; fruit ripening; isotope labeling; nonhuman; peptide dimethylation; priority journal; protein analysis; protein degradation; protein expression; protein folding; protein methylation; protein synthesis; proteomics; strawberry; stress

Symmetry of the fornix using diffusion tensor imaging - Sboto-Frankenstein, U.N.; Lazar, T.; Bolster, R.B.; Thind, S.; Dreessen de Gervai, P.; Gruwel, M.L.; Smith, S.D.; Tomanek, B. (Journal of Magnetic Resonance Imaging, 2013)
Purpose: To: 1) Present fornix tractography in its entirety for 20 healthy individuals to assess variability. 2) Provide individual and groupwise whole tract diffusion parameter symmetry assessments prior to clinical application. 3) Compare whole tract diffusion parameter assessments with tract-based spatial statistics (TBSS). Materials and Methods: Diffusion tensor imaging (DTI) data were acquired on a 3T Siemens magnetic resonance imaging (MRI) system using a single-shot spin echo planar imaging (EPI) sequence. Individual fornix tractography was conducted and whole tract diffusion parameter symmetries assessed. Whole tract results were compared with asymmetry contrasts conducted with voxelwise statistical analysis of diffusion parameters using TBSS. Results: The fornix tract could be visualized in its entirety including the columns, body, crura, and fimbria. Contrary to the crus and body, there were some tractography inconsistencies of the columns and fimbria across subjects. Although whole tract diffusion parameter asymmetries were nonsignificant, fractional anisotropy (FA) values bordered on statistical significance (P = 0.052). Using TBSS, significant FA asymmetries were identified (P ≤ 0.01, corrected). Conclusion: The findings demonstrate consistency of fornix tractography as well as some variability in the columns and fimbria. While parametric assessment demonstrates diffusion parameter symmetry, permutation-based TBSS analysis reveals significant FA asymmetries in the crura and fimbriae. © 2013 Wiley Periodicals, Inc.

Modeling and process control of MOCVD growth of InAlGaAs MQW structures on InP - Pitts, O.J.; Benyon, W.; SpringThorpe, A.J. (Journal of Crystal Growth, 2013)
We have developed a model which integrates calculation of InAlGaAs multiple quantum well (MQW) transition energies using the envelope function approximation with a statistical analysis of the PL emission wavelength, net strain and MQW period measured for a variety of MQW designs grown by MOCVD. The model relates the measured MQW parameters directly to MOCVD process parameters, allowing an accurate prediction of the process parameters required to grow a specified MQW design. This greatly reduces the need to grow and characterize individual calibration layers. The difference of the measured and predicted MQW parameters is recorded run-to-run over time, which allows process variability to be analyzed across a number of process parameters with intentional variations to grow different MQW designs. Crown Copyright © 2013.

Inhomogeneous transport in model hydrated polymer electrolyte supported ultrathin films - Damasceno Borges, D.; Franco, A.A.; Malek, K.; Gebel, G.; Mossa, S. (ACS Nano, 2013)
The structure of polymer electrolyte membranes, e.g., Nafion, inside fuel cell catalyst layers has significant impact on the electrochemical activity and transport phenomena that determine cell performance. In those regions, Nafion can be found as an ultrathin film, coating the catalyst and the catalyst support surfaces. The impact of the hydrophilic/hydrophobic character of these surfaces on the structural formation of the films and, in turn, on transport properties has not been sufficiently explored yet. Here, we report classical molecular dynamics simulations of hydrated Nafion thin films in contact with unstructured supports, characterized by their global wetting properties only. We have investigated structure and transport in different regions of the film and found evidence of strongly heterogeneous behavior. We speculate about the implications of our work on experimental and technological activity. © 2013 American Chemical Society.
Keywords: Classical molecular dynamics; Electrochemical activities; Fuel-cell catalyst layers; Hydrophilic/hydrophobic; Molecular dynamics simulations; Polymer electrolyte membranes; Technological activity; transport/nanostructure interplay; Catalysts; Fuel cells; Hydration; Molecular dynamics; Polyelectrolytes; Transport properties; Ultrathin films

Impact of surfactants on Pb (Zr0.53Ti0.47) O3 nanocrystal formation - Wan, Q.; Gu, Q.; Xing, J.; Chen, J. (Materials Letters, 2013)
In this article, we studied how surfactants can impact Pb (Zr 0.53Ti0.47) O3 (PZT) nanocrystal formation to result in interesting nanohexagon and nanorod shapes of PZT crystal. The PZT nanohexagons/nanorods with typical diameters and bounding lengths within the nanometer range were synthesized by sintering the mixture of PZT crystals. After annealing at 800 °C for 3 h, PZT nanohexagons were formed with Tween 20. Using the same sol-gel method and growth condition but with Tween 20 replaced by Triton X-100, PZT nanocrystals were formed having nanorod shapes. Their single-crystalline nanostructures and compositions were confirmed by high resolution transmission electronic microscopy (HR-TEM), X-ray diffraction (XRD) and Raman Spectra. The results of this study demonstrated new insight on how surfactants impact the morphology of PZT formation. © 2012 Elsevier B.V.
Keywords: Growth conditions; High resolution transmission electronic microscopy; Nano meter range; Nanocrystal formation; PZT; Single-crystalline; Triton X-100; Tween-20; Lead; Nanocrystals; Nanorods; Sintering; Sol-gel process; X ray diffraction; Zirconium; Surface active agents

Performance of cast-iron-pipe bell-spigot joints subjected to overburden pressure and ground movement - Rajani, B.; Abdel-Akher, A. (Journal of Pipeline Systems Engineering and Practice, 2013)
Bell split, in which a shard is separated from the bell end of a bell-spigot joint, is a predominant failure mode (in addition to longitudinal facture) that is observed in lead-caulked bell-spigot joints of large-diameter cast-iron pipes installed between 1850 and the early 1960s. This paper addresses three specific issues related to this type of failure of lead-caulked bell-spigot joints: (1) the extent to which cast-iron pipe joints can rotate without inducing stress in the bell; (2) the behavior of the bell-spigot lead-caulked joints; and (3) an estimate of the degree of settlement that two or more contiguous segments of jointed cast-iron pipe can tolerate before failure. The procedures described in this paper were motivated by the need to understand and explain the circumstances that lead to this failure mode in large-diameter cast-iron pipes. A mechanistic model accounts for lead material nonlinearity, wet and dry joint conditions encountered in water and gas pipelines, respectively, and existence or absence of asphalt coating on the outer pipe surface. The model is validated against experimental tests conducted in the mid-1930s on lead-caulked bell-spigot joints and is subsequently used to develop another model to predict the cumulative joint response of two or more contiguous pipesegments resting on an elastic medium and subject to overburden pressure followed by ground movement.Illustrative analyses of 400 and 1,200 mm diameter pipes clearly show that the extent to which a pipejoint can rotate without failure when subjected to ground movement gets smaller as the pipes become larger. The models developed in this paper to characterize joint behavior can be used to monitor pipe joint condition if actual joint rotations are measured when conducting pipe inspection © 2013 American Society of Civil Engineers.
Keywords: Asphalt coatings; Experimental test; Ground movement; Joint rotations; Material non-linearity; Mechanistic models; Overburden pressures; Pipe inspection; Cast iron pipe; Iron; Pipe joints; Bells

Geniposide regulates glucose-stimulated insulin secretion possibly through controlling glucose metabolism in INS-1 cells - Liu, J.; Guo, L.; Yin, F.; Zhang, Y.; Liu, Z.; Wang, Y. (PLoS ONE, 2013)
Glucose-stimulated insulin secretion (GSIS) is essential to the control of metabolic fuel homeostasis. The impairment of GSIS is a key element of β-cell failure and one of causes of type 2 diabetes mellitus (T2DM). Although the KATP channel-dependent mechanism of GSIS has been broadly accepted for several decades, it does not fully describe the effects of glucose on insulin secretion. Emerging evidence has suggested that other mechanisms are involved. The present study demonstrated that geniposide enhanced GSIS in response to the stimulation of low or moderately high concentrations of glucose, and promoted glucose uptake and intracellular ATP levels in INS-1 cells. However, in the presence of a high concentration of glucose, geniposide exerted a contrary role on both GSIS and glucose uptake and metabolism. Furthermore, geniposide improved the impairment of GSIS in INS-1 cells challenged with a high concentration of glucose. Further experiments showed that geniposide modulated pyruvate carboxylase expression and the production of intermediates of glucose metabolism. The data collectively suggest that geniposide has potential to prevent or improve the impairment of insulin secretion in β-cells challenged with high concentrations of glucose, likely through pyruvate carboxylase mediated glucose metabolism in β-cells. © 2013 Liu et al.
Keywords: 2 oxoglutaric acid; adenosine triphosphate; geniposide; glucose; pyruvate carboxylase; animal cell; article; cell protection; diabetes mellitus; enzyme activation; enzyme regulation; enzyme synthesis; gluconeogenesis; glucose metabolism; glucose transport; immunoblotting; insulin release; nonhuman; nucleotide sequence; pancreas islet beta cell; protein analysis; protein blood level; protein expression; protein function; rat

Head-and-face shape variations of U.S. civilian workers - Zhuang, Ziquing; Shu, Chang; Xi, Pencheng; Bergman, Michael; Joseph, Michael (Applied Ergonomics, 2013)
The objective of this study was to quantify head-and-face shape variations of U.S. civilian workers using modern methods of shape analysis. The purpose of this study was based on previously highlighted changes in U.S. civilian worker head-and-face shape over the last few decades - touting the need for new and better fitting respirators - as well as the study's usefulness in designing more effective personal protective equipment (PPE) - specifically in the field of respirator design. The raw scan three-dimensional (3D) data for 1169 subjects were parameterized using geometry processing techniques. This process allowed the individual scans to be put in correspondence with each other in such a way that statistical shape analysis could be performed on a dense set of 3D points. This process also cleaned up the original scan data such that the noise was reduced and holes were filled in. The next step, statistical analysis of the variability of the head-and-face shape in the 3D database, was conducted using Principal Component Analysis (PCA) techniques. Through these analyses, it was shown that the space of the head-and-face shape was spanned by a small number of basis vectors. Less than 50 components explained more than 90% of the variability. Furthermore, the main mode of variations could be visualized through animating the shape changes along the PCA axes with computer software in executable form for Windows XP. The results from this study in turn could feed back into respirator design to achieve safer, more efficient product style and sizing. Future study is needed to determine the overall utility of the point cloud-based approach for the quantification of facial morphology variation and its relationship to respirator performance.
Keywords: Anthropometric; 3D scan; Head-and-face modeling; Shape analysis; Respirator design

Tip apex shaping of gas field ion sources - Pitters, J.L.; Urban, R.; Vesa, C.; Wolkow, R.A. (Ultramicroscopy, 2013)
A procedure to control W(111) tip shape during etching to a single atom is described. It is demonstrated that the base of a single atom tip (SAT) can be shaped in order to alter the final operating voltage and emission opening angle of single atom tips for use as gas field ion sources or electron cold field emission sources. The operating voltages for single atom tips varied between 5 and 17. kV during helium ion beam generation. The emission properties of SATs were evaluated by fitting SAT images and measuring the full width at half maximum (FWHM) of the helium ion images. The FWHM is related to the linear opening angle and was evaluated as a function of SAT operating voltage. The results show that a forward focussing effect is observed such that the spot size decreases faster than is expected solely from an acceleration effect, indicating an affect from the tip shape. These results have consequences in designing gas field ion sources where etching is used to prepare the emitter. © 2013.
Keywords: Acceleration effects; Cold field emissions; Emission properties; Field ion microscopy; Gas field ion sources; Helium ion beams; Operating voltage; Single-atom tips; Atoms; Etching; Full width at half maximum; Helium; Ion sources; Gas industry; helium; nitrogen; article; chemical procedures; controlled study; electron microscopy; etching process; evaporation; gas field; image analysis; ionization; molecular dynamics; molecular imaging; molecular size; pressure measurement; procedures; single atom tip shaping; surface property

Profiling of cytokine and chemokine responses using multiplex bead array technology - Harris, G.; Chen, W. (Methods in Molecular Biology, 2013)
Multiplex bead array technology expands upon the principles of the enzyme-linked immunosorbent assay by allowing the simultaneous quantification of a large number of cytokines and chemokines within a single sample. This allows for the researcher more freedom to investigate complex immune responses both in vivo and in vitro. Here we describe the detailed assay protocol and technical tips for simultaneous quantification of multiple cytokines and chemokines in mouse biological fluids such as sera, bronchoalveolar lavage fluid, tissue homogenate supernatant, and tissue culture supernatant, using a multiplex bead array assay. © 2013 Springer Science+Business Media, LLC.
Keywords: chemokine; CXCL3 chemokine; cytokine; interleukin 1beta; interleukin 6; keratinocyte derived chemokine; macrophage inflammatory protein 1beta; monocyte chemotactic protein 1; RANTES; tumor necrosis factor alpha; animal tissue; article; blood analysis; controlled study; immunology test kit; lung lavage; microarray analysis; mouse; multiplex bead array assay; nonhuman; priority journal; quantitative analysis; supernatant; technology; tissue culture; tissue homogenate

Improving the formability of stainless steel 321 through multistep deformation for hydroforming applications - Anderson, M.; Gholipour, J.; Bridier, F.; Bocher, P.; Jahazi, M.; Savoie, J.; Wanjara, P. (Transactions of the Canadian Society for Mechanical Engineering, 2013)
Tube hydroforming (THF) is a well established process in the automotive industry and its application is being extended to the aerospace for manufacturing complex geometries. However, most of the alloys used in aerospace are high in strength and low in formability, which renders the application of THF more challenging. The objective of this paper is to present a method to increase the formability of an austenitic stainless steel. A multistep forming process was simulated through interrupted uniaxial tensile testing experiments to study the influence of the latter process on formability. The tensile test was divided into several deformation steps with a stress relief heat treatment after each forming step. The results indicated that the application of intermediate heat treatments considerably increased the formability of the stainless steel 321 alloy (SS321). Microstructure evolution as a function of deformation or heat treatment parameters was also investigated and revealed the formation of strain-induced martensite after the first deformation and heat treatment cycle without any deleterious effect on formability enhancement.
Keywords: Aerospace alloys; Heat treatment parameters; Intermediate heat treatment; Micro-structure evolutions; Multistep forming; Strain-induced martensite; Tube hydroforming; Uniaxial tensile testing; Alloys; Austenitic stainless steel; Automotive industry; Formability; Heat treatment; Microstructure; Stainless steel; Stress relief; Tensile testing; Tubes (components); Deformation

Exoplanets from the arctic: The first wide-field survey at 80°N - Law, N.M.; Carlberg, R.; Salbi, P.; Ngan, W.-H.W.; Ahmadi, A.; Steinbring, E.; Murowinski, R.; Sivanandam, S.; Kerzendorf, W. (Astronomical Journal, 2013)
Located within 10° of the North Pole, northern Ellesmere Island offers continuous darkness in the winter months. This capability can greatly enhance the detection efficiency of planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80°N, near Eureka, Nunavut, for a 152 hr observing campaign in 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm and 42 mm apertures, and they continuously imaged 504 and 1295 deg2, respectively. In total, the cameras took over 44,000 images and produced better than 1% precision light curves for approximately 10,000 stars. We describe a new high-speed astrometric and photometric data reduction pipeline designed for the systems, test several methods for the precision flat fielding of images from very-wide-angle cameras, and evaluate the cameras' image qualities. We achieved a scintillation-limited photometric precision of 1%-2% in each 10 s exposure. Binning the short exposures into 10 minute chunks provided a photometric stability of 2-3 mmag, sufficient for the detection of transiting exoplanets around the bright stars targeted by our survey. We estimate that the cameras, when operated over the full Arctic winter, will be capable of discovering several transiting exoplanets around bright (mV < 9.5) stars. © 2013. The American Astronomical Society. All rights reserved.

Enhancement of bone consolidation in mandibular distraction osteogenesis: A contemporary review of experimental studies involving adjuvant therapies - Hong, P.; Boyd, D.; Beyea, S.D.; Bezuhly, M. (Journal of Plastic, Reconstructive and Aesthetic Surgery, 2013)
Background One of the major disadvantages of mandibular distraction osteogenesis (MDO) is the prolonged time required for consolidation of the regenerate bone. The objective of the present study is to perform a contemporary review of various adjuvant therapies to enhance bone consolidation in MDO. Methods A PubMed search for articles related to MDO, along with the references of those articles, was performed. Inclusion and exclusion criteria were applied to all experimental studies assessing adjuvant therapies to enhance bone consolidation. Results A total of 1414 titles and abstracts were initially reviewed; 61 studies were included for full review. Many studies involved growth factors, hormones, pharmacological agents, gene therapy, and stem cells. Other adjuvant therapies included mechanical stimulation, laser therapy, and hyperbaric oxygen. Majority of the studies demonstrated positive bone healing effects and thus adjuvant therapies remain a viable strategy to enhance and hasten the consolidation period. Conclusion Although most studies have demonstrated promising results, many questions still remain, such as optimal amount, timing, and delivery methods required to stimulate the most favorable bone regeneration. As well, further studies comparing various adjuvant therapies and documentation of long-term adverse effects are required prior to clinical application. © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: adiponectin; alendronic acid; bone morphogenetic protein 2; bone morphogenetic protein 4; calcium hydroxide; calcium sulfate; deferoxamine; erythropoietin; fibroblast growth factor; icariin; nerve growth factor; osteogenic protein 1; simvastatin; somatomedin C; tissue inhibitor of metalloproteinase 1; zoledronic acid; angiogenesis; bone development; bone regeneration; distraction osteogenesis; electrostimulation; extracorporeal lithotripsy; gene therapy; human; hyperbaric oxygen; low intensity pulsed ultrasound; low level laser therapy; mandibular distraction osteogenesis; mechanical stimulation; membrane guided regeneration; mesenchymal stem cell; nonhuman; ossification; priority journal; protein expression; protein function; review; systematic review; ultrasound; Adjuvants, Pharmaceutic; Alendronate; Animals; Bone Morphogenetic Protein 4; Bone Regeneration; Disease Models, Animal; Dogs; Electric Stimulation Therapy; Erythropoietin; Genetic Therapy; Mandible; Nerve Growth Factor; Osteogenesis; Osteogenesis, Distraction; Rabbits; Rats; Risk Assessment; Stem Cell Transplantation; Treatment Outcome

A critical perspective on molecular electronic junctions: There is plenty of room in the middle - McCreery, R.L.; Yan, H.; Bergren, A.J. (Physical Chemistry Chemical Physics, 2013)
The promise of molecular electronic devices stems from the possibilities offered by the rich electronic structure of organic molecules. The use of molecules as functional components in microelectronic devices has long been envisioned to augment or even replace silicon. However, the understanding of what controls charge transport in these devices involves complexities stemming from numerous variables that are often interactive and exert a controlling influence on transport, confounding the role of the molecular component. This perspective discusses various aspects of molecular electronics, from the initial "vision quests" of single molecule, functional electronic elements, to the molecular tunnel junctions that have been studied and characterized in-depth. Aspects of energy level alignment are discussed in the context of charge transport mechanisms, as are important electronic interactions when molecules are bonded to conducting "contacts". In addition, integration of molecular components with microelectronic processing is considered, as are the prospects for functional, real-world devices. © the Owner Societies 2013.

Density-functional theory with dispersion-correcting potentials for methane: Bridging the efficiency and accuracy gap between high-level wave function and classical molecular mechanics methods - Torres, E.; Dilabio, G.A. (Journal of Chemical Theory and Computation, 2013)
Large clusters of noncovalently bonded molecules can only be efficiently modeled by classical mechanics simulations. One prominent challenge associated with this approach is obtaining force-field parameters that accurately describe noncovalent interactions. High-level correlated wave function methods, such as CCSD(T), are capable of correctly predicting noncovalent interactions, and are widely used to produce reference data. However, high-level correlated methods are generally too computationally costly to generate the critical reference data required for good force-field parameter development. In this work we present an approach to generate Lennard-Jones force-field parameters to accurately account for noncovalent interactions. We propose the use of a computational step that is intermediate to CCSD(T) and classical molecular mechanics, that can bridge the accuracy and computational efficiency gap between them, and demonstrate the efficacy of our approach with methane clusters. On the basis of CCSD(T)-level binding energy data for a small set of methane clusters, we develop methane-specific, atom-centered, dispersion-correcting potentials (DCPs) for use with the PBE0 density-functional and 6-31+G(d,p) basis sets. We then use the PBE0-DCP approach to compute a detailed map of the interaction forces associated with the removal of a single methane molecule from a cluster of eight methane molecules and use this map to optimize the Lennard-Jones parameters for methane. The quality of the binding energies obtained by the Lennard-Jones parameters we obtained is assessed on a set of methane clusters containing from 2 to 40 molecules. Our Lennard-Jones parameters, used in combination with the intramolecular parameters of the CHARMM force field, are found to closely reproduce the results of our dispersion-corrected density-functional calculations. The approach outlined can be used to develop Lennard-Jones parameters for any kind of molecular system. © Published 2013 by the American Chemical Society.

On the density profile of the globular cluster M92 - Di Cecco, A.; Zocchi, A.; Varri, A.L.; Monelli, M.; Bertin, G.; Bono, G.; Stetson, P.B.; Nonino, M.; Buonanno, R.; Ferraro, I.; Iannicola, G.; Kunder, A.; et al. (Astronomical Journal, 2013)
We present new number density and surface brightness profiles for the globular cluster M92 (NGC 6341). These profiles are calculated from optical images collected with the CCD mosaic camera MegaCam at the Canada-France-Hawaii Telescope and with the Advanced Camera for Surveys on the Hubble Space Telescope. The ground-based data were supplemented with the Sloan Digital Sky Survey photometric catalog. Special care was taken to discriminate candidate cluster stars from field stars and to subtract the background contamination from both profiles. By examining the contour levels of the number density, we found that the stellar distribution becomes clumpy at radial distances larger than ∼13′, and there is no preferred orientation of contours in space. We performed detailed fits of King and Wilson models to the observed profiles. The best-fit models underestimate the number density inside the core radius. Wilson models better represent the observations, in particular in the outermost cluster regions: the good global agreement of these models with the observations suggests that there is no need to introduce an extra-tidal halo to explain the radial distribution of stars at large radial distances. The best-fit models for the number density and the surface brightness profiles are different, even though they are based on the same observations. Additional tests support the evidence that this fact reflects the difference in the radial distribution of the stellar tracers that determine the observed profiles (main-sequence stars for the number density, bright evolved stars for the surface brightness). © 2013. The American Astronomical Society. All rights reserved.

Oxide films in laser additive manufactured Inconel 718 - Zhang, Y.N.; Cao, X.; Wanjara, P.; Medraj, M. (Acta Materialia, 2013)
A continuous-wave 5 kW fiber laser welding system was used in conduction mode to deposit Inconel® alloy 718 (IN718) by employing filler wire on as-serviced IN718 parent material (PM) substrates. The direct laser deposited (DLD) coupons and as-serviced IN718 PM were then evaluated through tensile testing. To understand the failure mechanisms, the tensile fracture surfaces of the as-serviced IN718 PM, DLD and DLD-PM samples were analyzed using scanning electron microscopy. The fracture surfaces revealed the presence of both Al 2O3 and Cr2O3 films, although the latter was reasoned to be the main oxide in IN718. Both the experimental observations and thermodynamic analysis indicated that oxidation of some alloying elements in IN718 cannot be completely avoided during manufacturing, whether in the liquid state under vacuum (for casting, the electron beam melting, welding and/or deposition) or with inert gas protection (for welding or laser deposition). The exposed surface of the oxide film on the fracture surface has poor wetting with the metal and thus can constitute a lack of bonding or a crack with either the metal and/or another non-wetted side of the oxide film. On the other hand, the wetted face of the oxide film has good atom-to-atom contact with the metal and may nucleate some intermetallic compounds, such as Laves, Ni3Nb-δ, Nb-rich MC and γ′ compounds. The potential of their nucleation on Cr 2O3 was assessed using planar disregistry. Coherent planes were found between these intermetallics and Cr2O3.
Keywords: Additive Manufacturing; Continuous waves; Failure mechanism; Fracture surfaces; Laser depositions; Parent materials; Tensile fracture surfaces; Thermo dynamic analysis; Alloying elements; Deposition; Fiber lasers; Hydrogen embrittlement; Inert gases; Intermetallics; Manufacture; Niobium; Niobium compounds; Scanning electron microscopy; Sodium compounds; Soldering alloys; Tensile strength; Tensile testing; Thermoanalysis; Welding; Wetting; Oxide films

Pasteurella multocida heddleston serovar 3 and 4 strains share a common lipopolysaccharide biosynthesis locus but display both inter- and intrastrain lipopolysaccharide heterogeneity - Harper, M.; St.Michael, F.; John, M.; Vinogradov, E.; Steen, J.A.; van Dorsten, L.; Turni, C.; Blackall, P.J.; Adler, B.; Cox, A.D.; Boycea, J.D. (Journal of Bacteriology, 2013)
Pasteurella multocida is a Gram-negative multispecies pathogen and the causative agent of fowl cholera, a serious disease of poultry which can present in both acute and chronic forms. The major outer membrane component lipopolysaccharide (LPS) is both an important virulence factor and a major immunogen. Our previous studies determined the LPS structures expressed by different P. multocida strains and revealed that a number of strains belonging to different serovars contain the same LPS biosynthesis locus but express different LPS structures due to mutations within glycosyltransferase genes. In this study, we report the full LPS structure of the serovar 4 type strain, P1662, and reveal that it shares the same LPS outer core biosynthesis locus, L3, with the serovar 3 strains P1059 and Pm70. Using directed mutagenesis, the role of each glycosyltransferase gene in LPS outer core assembly was determined. LPS structural analysis of 23 Australian field isolates that contain the L3 locus revealed that at least six different LPS outer core structures can be produced as a result of mutations within the LPS glycosyltransferase genes. Moreover, some field isolates produce multiple but related LPS glycoforms simultaneously, and three LPS outer core structures are remarkably similar to the globo series of vertebrate glycosphingolipids. Our in-depth analysis showing the genetics and full range of P. multocida lipopolysaccharide structures will facilitate the improvement of typing systems and the prediction of the protective efficacy of vaccines. © 2013, American Society for Microbiology.
Keywords: bacterium lipopolysaccharide; galactosyltransferase; glycosyltransferase; article; bacterial growth; bacterium isolation; biosynthesis; carbohydrate analysis; controlled study; crystal structure; DNA sequence; electrospray mass spectrometry; Escherichia coli; gene locus; gene mutation; genotype; missense mutation; mutagenesis; nonhuman; nonsense mutation; nuclear magnetic resonance spectroscopy; nucleotide sequence; Pasteurella multocida; priority journal; promoter region; serotype

Genome-based bioinformatic prediction of major histocompatibility complex (MHC) epitopes - Foote, S.J. (Methods in Molecular Biology, 2013)
Over the last 12 years, a large amount of knowledge has been accumulated on various aspects of Major Histocompatibility Complex (MHC) molecules. In conjunction, numerous algorithms and tools have been developed to screen protein molecules for these MHC receptor sites. By combining these computational tools and databases with genomic sequence information that is now widely available for a vast range of organisms, it is possible to screen whole genomes for MHC epitopes. By prescreening these genomes, it allows the researcher to narrow down possible protein targets for further analysis by traditional tools such as gene knockouts and animal efficacy studies. © 2013 Springer Science+Business Media, LLC.
Keywords: epitope; algorithm; article; bioinformatics; CD8+ T lymphocyte; computer program; data base; gene inactivation; gene sequence; genome; major histocompatibility complex; mouse; nonhuman; nucleotide sequence; priority journal; protein localization

Cerebral endothelial expression of Robo1 affects brain infiltration of polymorphonuclear neutrophils during mouse stroke recovery - Gangaraju, S.; Sultan, K.; Whitehead, S.N.; Nilchi, L.; Slinn, J.; Li, X.; Hou, S.T. (Neurobiology of Disease, 2013)
Increased brain infiltration of polymorphonuclear neutrophils (PMNs) occurs early after stroke and is important in eliciting brain inflammatory response during stroke recovery. In order to understand the molecular mechanism of PMN entry, we investigated the expression and requirement for Slit1, a chemorepulsive guidance cue, and its cognate receptor, Robo1, in a long-term recovery mouse model of cerebral ischemia. The expression levels of Robo1 were significantly decreased bilaterally at 24. h following reperfusion. Robo1 expression levels remained suppressed in the ipsilateral cortex until 28. d post MCAO-reperfusion, while the levels of Robo1 in the contralateral cortex recovered to the level of sham-operated mouse by 7. d reperfusion. Circulating PMNs express high levels of Slit1, but not Robo1. Influx of PMNs into the ischemic core area occurred early (24. h) after cerebral ischemia, when endothelial Robo1 expression was significantly reduced in the ischemic brain, indicating that Robo1 may form a repulsive barrier to PMN entry into the brain parenchyma. Indeed, blocking Slit1 on PMNs in a transwell migration assay in combination with an antibody blocking of Robo1 on human umbilical vein endothelial cells (HUVEC) significantly increased PMN transmigration during oxygen glucose deprivation, an in vitro model of ischemia. Collectively, in the normal brain, the presence of Slit1 on PMNs, and Robo1 on cerebral endothelial cells, generated a repulsive force to prevent the infiltration of PMNs into the brain. During stroke recovery, a transient reduction in Robo1 expression on the cerebral endothelial cells allowed the uncontrolled infiltration of Slit1-expressing PMNs into the brain causing inflammatory reactions. © 2013.
Keywords: glucose; oxygen; receptor protein; ROBO1 protein; Slit protein; Slit1 protein; unclassified drug; animal experiment; animal model; animal tissue; article; brain blood vessel; brain cortex; brain ischemia; brain tissue; cell migration; cerebrovascular accident; controlled study; convalescence; endothelium cell; human; human cell; in vitro study; inflammation; middle cerebral artery occlusion; mouse; neutrophil chemotaxis; nonhuman; priority journal; protein expression; reperfusion; sham procedure; umbilical vein endothelial cell; vascular endothelium; Animals; Blotting, Western; Brain; Chemotaxis, Leukocyte; Disease Models, Animal; Endothelial Cells; HEK293 Cells; Humans; Immunohistochemistry; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Neutrophils; Receptors, Immunologic; Stroke; Transfection

Seds: The spitzer extended deep survey. Survey design, photometry, and deep irac source counts - Ashby, M.L.N.; Willner, S.P.; Fazio, G.G.; Huang, J.-S.; Arendt, R.; Barmby, P.; Barro, G.; Bell, E.F.; Bouwens, R.; Cattaneo, A.; Croton, D.; Davé, R.; et al. (The Astrophysical Journal, 2013)
The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg 2 to a depth of 26 AB mag (3σ) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 μm. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 ± 1.0 and 4.4 ± 0.8 nW m-2 sr-1 at 3.6 and 4.5 μm to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component. © 2013. The American Astronomical Society. All rights reserved.

Requirement of the lipopolysaccharide O-chain biosynthesis gene wxocB for type III secretion and virulence of Xanthomonas oryzae pv. Oryzicola - Wang, L.; Vinogradov, E.V.; Bogdanove, A.J. (Journal of Bacteriology, 2013)
Xanthomonas oryzae pv. oryzicola causes bacterial leaf streak of rice. A mutant disrupted in wxocB, predicted to encode an enzyme for lipopolysaccharide (LPS) synthesis, was previously shown to suffer reduced virulence. Here, we confirm a role for wxocB in virulence and demonstrate its requirement for LPS O-chain assembly. Structure analysis indicated that wild-type LPS contains a polyrhamnose O chain with irregular, variant residues and a core oligosaccharide identical to that of other Xanthomonas spp. and that the wxocB mutant lacks the O chain. The mutant also showed moderate impairment in exopolysaccharide (EPS) production, but comparison with an EPS-deficient mutant demonstrated that this impairment could not account entirely for the reduced virulence. The wxocB mutant was not detectably different from the wild type in its induction of pathogenesis- related rice genes, type II secretion competence, flagellar motility, or resistance to two phytoalexins or resveratrol, and it was more, not less, resistant to oxidative stress and a third phytoalexin, indicating that none of these properties is involved. The mutant was more sensitive to SDS and to novobiocin, so increased sensitivity to some host-derived antimicrobials cannot be ruled out. However, the mutant showed a marked decrease in type III secretion into plant cells. This was not associated with any change in expression of genes for type III secretion or the ability to attach to plant cells in suspension. Thus, virulence of the wxocB mutant is likely reduced due primarily to a direct, possibly structural, effect of the loss of the O chain on type III delivery of effector proteins. © 2013, American Society for Microbiology.
Keywords: exopolysaccharide; lipopolysaccharide; novobiocin; phytoalexin; resveratrol; antibiotic resistance; article; biosynthesis; mutant; nonhuman; oxidative stress; pathogenesis; plant cell; priority journal; structure analysis; virulence; wild type; Xanthomonas oryzae; Bacterial Proteins; Bacterial Secretion Systems; Gene Expression Regulation, Bacterial; Glucosyltransferases; Lipopolysaccharides; Molecular Structure; Mutation; Oryza sativa; Plant Diseases; Protein Transport; Virulence; Xanthomonas; Bacteria (microorganisms); Xanthomonas; Xanthomonas oryzae pv. oryzicola

The impact of SO2 on post combustion carbon dioxide capture in bed of silica sand through hydrate formation - Daraboina, N.; Ripmeester, J.; Englezos, P. (International Journal of Greenhouse Gas Control, 2013)
Hydrate crystallization technology is one of the novel approaches for capturing carbon dioxide from flue gases. The presence of impurities such as SO2, NO2, H2S can influence the CO2 hydrate formation process. In the present work the impact of SO2 on hydrate equilibrium was investigated using the isothermal pressure search method. The hydrate equilibrium shifted to low pressures and high temperatures in the presence of small amount SO2. For example the hydrate formation pressure shifted from 7.7MPa to 7.25MPa at 273.75K. In addition, the presence of SO2 enhanced the initial hydrate formation rate and final moles of gas consumed 16h after the hydrate nucleation. The CO2 and SO2 gases were preferentially incorporated into the hydrate phase. The presence of SO2 helps the thermodynamics and kinetics of the hydrate formation process. Therefore complete removal of this SO2 impurity is not necessary; in fact it aids both thermodynamically and kinetically for hydrate formation, which indeed is a positive factor for the capture and geological sequestration of CO2 in the form of hydrates. The addition of THF reduces the CO2/N2/SO2 hydrate formation conditions (from 7.25MPa to 0.15MPa at 273.75K), which is practically important for reducing high compression costs. Moreover, the presence of THF decreases the hydrate nucleation time but reduces the hydrate formation rate significantly. © 2013.
Keywords: Carbon dioxide capture; Geological sequestration of CO; Hydrate formation conditions; Hydrate formation process; Hydrate nucleation; Sequestration; Thermodynamics and kinetics; THF; Carbon capture; Carbon dioxide; Flue gases; Hydration; Impurities; Nucleation; Porous materials; Removal; Sulfur dioxide; Gas hydrates; carbon dioxide; carbon sequestration; combustion; gas hydrate; P-T conditions; porous medium; silica; sulfur dioxide; thermodynamics

In situ tribometry of cold-sprayed Al-Al2O3 composite coatings - Shockley, J.M.; Strauss, H.W.; Chromik, R.R.; Brodusch, N.; Gauvin, R.; Irissou, E.; Legoux, J.-G. (Surface and Coatings Technology, 2013)
An in situ tribometer utilizing a transparent hemispherical counterface was used to conduct sliding wear tests on Al-Al2O3 composite coatings deposited by cold spray. Direct observation of the wear interface via the slider allowed for correlation to be identified between the formation of transfer film and friction changes, wear rates, and the evolution of subsurface structures. It was revealed that the presence of hard particles in the Al-Al2O3 coating stabilized the transfer film, characterized by less plastic flow and fewer instances of hole formation at the interface. This increase in stability correlated with lower wear rates, stable friction, and the formation of a mechanically mixed layer (MML) in the worn subsurface. © 2012 Elsevier B.V.
Keywords: Cold spray; Mechanically mixed layers; Metal matrix composite coatings; Situ tribologies; Third body; Aluminum coatings; Cladding (coating); Composite coatings; Friction; Interfaces (materials); Wear of materials; Aluminum

Analysis of a ferric uptake regulator (Fur) knockout mutant in Aeromonas salmonicida subsp. salmonicida - Ebanks, R.O.; Goguen, M.; Knickle, L.; Dacanay, A.; Leslie, A.; Ross, N.W.; Pinto, D.M. (Veterinary Microbiology, 2013)
Aeromonas salmonicida subsp. salmonicida is the etiological agent of furunculosis; a serious infectious disease in aquaculture raised salmonids. Iron acquisition has been shown to be critical for the survival of pathogenic bacteria during the course of infection. Previous work has demonstrated that A. salmonicida expresses iron-repressible IROMP proteins, suggesting the presence of iron acquisition systems that are under the control of a ferric uptake regulator (Fur). In this study, the A. salmonicida fur has been sequenced and a fur deletion strain generated. The A. salmonicida fur gene has an open reading frame of 428. bp, coding for a protein of 143 amino acids, and with high homology to previously described Fur proteins. The Fur protein product had a 94% sequence identity and 96% sequence similarity to the Aeromonas hydrophila Fur protein product. Transcription of the A. salmonicida fur gene was not regulated by the iron status of the bacterium and is not autoregulated, as in Escherichia coli. Proteomic analysis of the A. salmonicida fur mutant, fails to repress iron-regulated outer membrane proteins in the presence of iron. The A. salmonicida fur::KO mutant shows significantly reduced pathogenicity compared to the wild-type parental strain. In addition, the A. salmonicida fur mutant provides an important tool for further investigation of the iron acquisition mechanisms utilized by A. salmonicida. © 2012 Elsevier B.V..
Keywords: ferric uptake regulator; iron; outer membrane protein C; siderophore; Aeromonas hydrophila; Aeromonas salmonicida; amino acid sequence; article; autoregulation; bacterial gene; bacterial growth; bacterial strain; Escherichia coli; gene deletion; nonhuman; open reading frame; protein analysis; protein purification; proteomics; reverse transcription polymerase chain reaction; sequence analysis; wild type; Aeromonas hydrophila; Aeromonas salmonicida; Aeromonas salmonicida subsp. salmonicida; Bacteria (microorganisms); Escherichia coli; Salmonidae

Increased sky coverage with optimal correction of tilt and tilt-anisoplanatism modes in laser-guide-star multiconjugate adaptive optics - Correia, C.; Véran, J.-P.; Herriot, G.; Ellerbroek, B.; Wang, L.; Gilles, L. (Journal of the Optical Society of America A: Optics and Image Science, and Vision, 2013)
Laser-guide-star multiconjugate adaptive optics (MCAO) systems require natural guide stars (NGS) to measure tilt and tilt-anisoplanatism modes. Making optimal use of the limited number of photons coming from such, generally dim, sources is mandatory to obtain reasonable sky coverage, i.e., the probability of finding asterisms amenable to NGS wavefront (WF) sensing for a predefined WF error budget. This paper presents a Strehl-optimal (minimum residual variance) spatiotemporal reconstructor merging principles of modal atmospheric tomography and optimal stochastic control theory. Simulations of NFIRAOS, the first light MCAO system for the thirty-meter telescope, using ~500 typical NGS asterisms, show that the minimum-variance (MV) controller delivers outstanding results, in particular for cases with relatively dim stars (down to magnitude 22 in the H-band), for which lowtemporal frame rates (as low as 16 Hz) are required to integrate enough flux. Over all the cases tested ~21 nm rms median improvement in WF error can be achieved with the MV compared to the current baseline, a type-II controller based on a double integrator. This means that for a given level of tolerable residual WF error, the sky coverage is increased by roughly 10%, a quite significant figure. The improvement goes up to more than 20% when compared with a traditional single-integrator controller. © 2013 Optical Society of America.
Keywords: Atmospheric tomography; Double integrator; Multi-conjugate adaptive optics systems; Multiconjugate adaptive optics; Natural guide star; Optimal correction; Optimal stochastic control; Thirty Meter Telescope; Mineralogy; Optimization; Stars

Optical properties of charged quantum dots doped with a single magnetic impurity - Mendes, U.C.; Korkusinski, M.; Trojnar, A.H.; Hawrylak, P. (Physical Review B - Condensed Matter and Materials Physics, 2013)
We present a microscopic theory of the optical properties of self-assembled quantum dots doped with a single magnetic manganese (Mn) impurity and containing a controlled number of electrons. The single-particle electron and heavy-hole electronic shells are described by two-dimensional harmonic oscillators. The electron-electron, electron-hole Coulomb as well as the short-range electron spin-Mn spin and hole spin-Mn spin contact exchange interactions are included. The electronic states of the photoexcited electron-hole-Mn complex and of the final electron-Mn complex are expanded in a finite number of configurations and the full interacting Hamiltonian is diagonalized numerically. The emission spectrum is predicted as a function of photon energy for a given number of electrons and different number of confined electronic quantum dot shells. We show how emission spectra allow to identify the number of electronic shells, the number of electrons populating these shells and, most importantly, their spin. We show that electrons not interacting directly with the spin of Mn ion do so via electron-electron interactions. This indirect interaction is a strong effect even when Mn impurity is away from the quantum dot center. © 2013 American Physical Society.

Synthesis and characterization of a structure H hydrate formed with carbon dioxide and 3,3-dimethyl-2-butanone - Tezuka, K.; Shen, R.; Watanabe, T.; Takeya, S.; Alavi, S.; Ripmeester, J.A.; Ohmura, R. (Chemical Communications, 2013)
Experiments were carried out to synthesize and characterize a structure H clathrate hydrate containing CO2 and 3,3-dimethyl-2-butanone (pinacolone) by means of phase equilibrium and powder X-ray diffraction measurements. Molecular dynamics simulations of this structure H hydrate were performed to understand the nature of guest-host molecular interactions. © 2013 The Royal Society of Chemistry.
Keywords: 2 butanone; carbon dioxide; pinacolone; unclassified drug; article; molecular dynamics; molecular interaction; synthesis; X ray diffraction

The effective g-factor in In0.53Ga0.47As/In 0.52Al0.48As quantum well investigated by magnetotransport measurement - Liu, X. Z.; Xu, Y. G.; Yu, G.; Wei, L. M.; Lin, T.; Guo, S. L.; Chu, J. H.; Zhou, W. Z.; Zhang, Y. G.; Lockwood, David J. (Journal of Applied Physics, 2013)
The magneotransport properties of a high carrier concentration and high mobility 20-nm thick In0.53Ga0.47As/In 0.52Al0.48As quantum well (QW) are investigated by tilt angle dependent Shubnikov-de Haas oscillations and by weak antilocalization (WAL) in an in-plane magnetic field. The effective g-factor g* and zero field spin splitting Δ 0 are extracted from tilt angle dependent beating pattern. We found that g* shows a dramatic reduction with increasing carrier density due to the increased effective band gap. Furthermore, an anomalously rapid suppression of the WAL effect with increasing in-plane magnetic field B|| is observed. This reveals that the total dephasing rate is not solely contributed by Zeeman splitting. The microroughness scattering in the QW is proposed to be another factor to cause the dephasing and thus responsible for this effect. © 2013 American Institute of Physics.
Keywords: Dephasing; Dephasing rates; Effective band gap; Effective g-factor; High mobility; In-plane magnetic fields; Magneto-transport measurement; Micro-roughness; Shubnikov-de Haas oscillations; Tilt angle; Weak antilocalization; Zeeman splittings; Zero-field spin splitting; Carrier concentration; Gallium; Semiconductor quantum wells

A bobsleigh ice friction model - Lozowski, E.; Szilder, K.; Poirier, L. (Proceedings of the International Offshore and Polar Engineering Conference, 2013)
Ice friction affects us in many ways, from slippery roads to winter sports. In cold regions, ice friction influences ice interaction with itself, which determines the motion of ice floes. It also influences the structural forces resulting from ice interactions with fixed and moored structures and with floating vessels. Ice friction also affects surface transportation over snow and ice. This paper addresses only one aspect of ice friction in winter sports, but it is potentially relevant to other applications, particularly surface transportation over ice. The model of ice friction described here is for a steel bobsleigh runner sliding on ice at high velocity. The model describes ice friction in the fully-lubricated, hydrodynamic regime, where a layer of meltwater completely separates the ice and slider surfaces. The effect of any contact between asperities on both surfaces is neglected. Friction results from a ploughing force, arising from ice deformation, crushing and extrusion, and from the shear stress in the lubricating Couette flow. The model takes into account frictional melting, heat conduction into the ice and the lateral squeeze flow of the lubricating liquid. The effect of pressure on the melting temperature is also accounted for. Sensitivity testing of the numerical model has been conducted to examine the influence of such factors as runner dimensions, sliding speed, ice temperature and g-forces. A comparison with recent measurements of bobsled ice friction made by one of the authors is encouraging, suggesting that the model has identified and adequately represented the most essential physical processes. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE).
Keywords: Bobsleigh; Effect of pressure; Frictional melting; Hydrodynamic regime; Moored structures; Structural forces; Surface transportation; Theory; Friction; Ice; Models; Physics; Sailing vessels; Sea ice; SportS; Lubrication

Discovery of a new member of the inner oort cloud from the Next Generation Virgo Cluster Survey - Chen, Ying-Tung; Kavelaars, J. J.; Gwyn, Stephen; Ferrarese, Laura; Côté, Patrick; Jordán, Andrés; Suc, Vincent; Cuillandre, Jean-Charles; Ip, Wing-Huen (The Astrophysical Journal Letters, 2013)
We report the discovery of 2010 GB174, a likely new member of the Inner Oort Cloud (IOC). 2010 GB174 is 1 of 91 trans-Neptunian objects and Centaurs discovered in a 76 deg2 contiguous region imaged as part of the Next Generation Virgo Cluster Survey (NGVS) - a moderate ecliptic latitude survey reaching a mean limiting magnitude of g′ ≃ 25.5 - using MegaPrime on the 3.6 m Canada-France-Hawaii Telescope. 2010 GB 174 is found to have an orbit with a semi-major axis of a ≃ 350.8 AU, an inclination of i ≃ 21.°6, and a pericenter of q ∼ 48.5 AU. This is the second largest perihelion distance among known solar system objects. Based on the sky coverage and depth of the NGVS, we estimate the number of IOC members with sizes larger than 300 km (HV ≤ 6.2 mag) to be ≃ 11, 000. A comparison of the detection rate from the NGVS and the PDSSS (a characterized survey that "rediscovered" the IOC object Sedna) gives, for an assumed a power-law luminosity function for IOC objects, a slope of α ≃ 0.7 ± 0.2. With only two detections in this region this slope estimate is highly uncertain.

External and internal corrosion of large-diameter cast iron mains - Rajani, B.; Kleiner, Y. (Journal of Infrastructure Systems, 2013)
Deterioration in cast iron mains manifests itself in the form of corrosion. External corrosion is typically found to occur in pipes buried in corrosive soils while internal corrosion is dependent on water chemistry and flow characteristics. In the literature, corrosion of cast ron pipes (external and internal) is typically characterized by corrosion pit depth even though corroded area and corroded pit volume as well as pit location may enhance this characterization. Knowledge of these corrosion pit properties permits the assessment of its structural integrity. Typically, internal and external corrosion pits and corroded areas are observed to occur in many irregular shapes and sizes, which make their characterization a challenge. This paper describes extreme value statistical models that can be used to estimate external and internal corrosion pit depths in cast iron pipes using indirect properties or parameters. The goal of these corrosion models is to be able to predict corrosion pit depth based on available data with an acceptable degree of confidence. The external corrosion model is calibrated using external corrosion ata collected by ThamesWater Utilities Ltd (TWUL) and subsequently validated with data obtained from the inspection of four cast iron pipe lengths. The internal corrosion model was calibrated using internal corrosion data but sufficient appropriate data was not available for its validation. © 2013 American Society of Civil Engineers.

Hydroxyl anion conducting membranes poly(vinyl alcohol)/ poly(diallyldimethylammonium chloride) for alkaline fuel cell applications: Effect of molecular weight - Zhang, J.; Zhou, T.; Qiao, J.; Liu, Y. (Electrochimica Acta, 2013)
Hydroxyl anion conducting membranes have been developed using poly(vinyl alcohol) (PVA) as polymermatrix by incorporation of poly(diallyldimethylammonium chloride) (PDDA) as anion charge carriers. PDDA of four different molecular weight (namely PDDA-HMw, PDDA-MMw, PDDA-LMw and PDDA-ULMw) was incorporated in order to clarifying the effect of molecular weight on membrane performances. The membranes are characterized in detail by FTIR spectroscopy, scanning electron microscopy (SEM), thermal gravity analysis (TG), mechanical property, AC impedance technique, water uptake, swelling ratio, oxidation and alkaline stability to evaluate their applicability in alkaline fuel cells. The OH -conductivity of the membranes was found to be increased with increasing molecular weight of PDDA, and the maximum OH-conductivity of 0.027 S cm-1was achieved for PVA/PDDA-HMw membrane. ThePVA/PDDA-HMw membrane also showed the best mechanical property and excellent thermal stability due to the most compact and dense network structure. All the membranes showed relatively highoxidative stability in 30% H2O2and strong alkaline stability in 2 M KOH for 624 h at room temperature. The fuel cell performances of the MEAs with these membranes were 18.2, 23.4, 28.5 and 35.1 mW cm-2using H2and O2gases at 25°C. The long-term stability of single-cell performance showed that the PVA/PDDA membrane could approximately last 80 h on the fuel cell with only a slight decrease of 0.1 V in cell potential. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Alkaline anion-exchange membranes; Dense network structures; Hydroxide conductivities; Molecular weight effect; Poly (vinyl alcohol) (PVA); Poly(diallyldimethylammonium chloride); Single cell performance; Thermal gravity analysis; Alkaline fuel cells; Biomechanics; Chlorine compounds; Convergence of numerical methods; Fourier transform infrared spectroscopy; Ions; Mechanical properties; Membranes; Molecular weight; Polyvinyl alcohols; Scanning electron microscopy; Stability; Clarification

Gender differences in the relationship between smoking and frailty: Results from the Beijing longitudinal study of aging - Wang, C.; Song, X.; Mitnitski, A.; Yu, P.; Fang, X.; Tang, Z.; Shi, J.; Rockwood, K. (Journals of Gerontology - Series A Biological Sciences and Medical Sciences, 2013)
Background. Smoking is common in China, where the population is aging rapidly. This study evaluated the relationship between smoking and frailty and their joint association with health and survival in older Chinese men and women.Methods.Data came from the Beijing Longitudinal Study of Aging, a representative cohort study with a 15-year follow-up. Community-dwelling people (n = 3257) aged more than 55 years at baseline were followed between 1992 and 2007, during which time 51% died. A frailty index (FI) was constructed from 28 self-reported health deficits.Results.Almost half (1,485 people; 45.6%) of the participants reported smoking at baseline (66.8% men, 25.3% women). On average, male smokers were frailer (FI = 0.17±0.13) than male nonsmokers (FI = 0.13±0.10; p =. 038). No such differences were seen in women. Men who smoked had the lowest survival probability; female nonsmokers had the highest. Compared with female nonsmokers, the risk of death for male smokers was 1.58 (95% CI = 1.41-1.95; p <. 001), adjusted for age and education. Across all FI values, female smokers and male nonsmokers had comparable survival rates.Conclusion.Smoking was associated with an increased rate of both worsening health and mortality. At all levels of health status, as defined by deficit accumulation, women who smoked lost the survival advantage conferred by their sex. © 2012 The Author.
Keywords: age; aged; article; China; cohort analysis; educational status; female; frail elderly; health status; human; longitudinal study; male; marriage; mortality; multivariate analysis; sex difference; smoking; Age Factors; Aged; Aged, 80 and over; China; Cohort Studies; Educational Status; Female; Frail Elderly; Health Status; Humans; Longitudinal Studies; Male; Marital Status; Mortality; Multivariate Analysis; Sex Factors; Smoking

Twenty years of performance-based fire protection design: Challenges faced and a look ahead - Alvarez, A.; Meacham, B.J.; Dembsey, N.A.; Thomas, J.R. (Journal of Fire Protection Engineering, 2013)
A review of two decades of worldwide experience using standards, codes and guidelines related to performance-based fire protection design for buildings has identified shortcomings in the interpretation, application and implementation of the performance-based design process, apparent inconsistency in the resulting levels of performance achieved and several opportunities to enhance the process. In a constantly evolving building environment, technical challenges have to be overcome because fire safety engineering still depends greatly on knowledge gained from scientific and engineering research across a broad range of disciplines (e.g., better understanding of the fire phenomena, the behavior and response of the building occupants/contents/structure to the fire, tools for engineering analysis and all the necessary data needed to support tool application). Political challenges also need to be considered as performance-based fire protection design requires the approval of the authority having jurisdiction and other involved stakeholders, at several of its different steps (design, construction, original usage, modifications of usage). The review presented here has been undertaken from an engineering perspective rather than a regulatory perspective. Two key outcomes of this engineering review are that several of the challenges that have been identified are strongly linked to the application of generic guidance to specific problems, which results in critical details being missed, and that some of the engineering issues are treated within a political context, while they should be addressed as purely technical issues. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
Keywords: Authority having jurisdictions; Engineering analysis; Engineering perspective; Engineering process; Fire safety engineering; Literature reviews; Performance based design; Protection designs; Engineering; Fire extinguishers; Fire protection; Tools; Structural design

Graph theory based model for learning path recommendation - Durand, G.; Belacel, N.; Laplante, F. (Information Sciences, 2013)
Learning design, the activity of designing a learning path, can be a complex task, especially for learners. A learning design recommendation system would help self-learners find appropriate learning objects and build efficient learning paths during their learning journey. Educational Data Mining (EDM) has provided an impressive amount of novelties related to learning object recommendation systems. However, most of the solutions proposed thus far do not take into account eventual competency dependencies among learning objects and/or are not designed for large repositories of interdependent learning objects. We propose a model to build a learning design recommendation system based on graph theory. From this model, we propose, implement and test an approach using the concept of cliques to recommend learning paths. © 2013 Published by Elsevier Inc. All rights reserved.
Keywords: Complex task; Educational data minings (EDM); Efficient learning; Learning designs; Learning objects; Learning paths; Design; Graph theory; Recommender systems; Soft computing; Learning systems

Understanding the effects of backpressure on PEM fuel cell reactions and performance - Zhang, J.; Song, C.; Baker, R.; Zhang, L. (Journal of Electroanalytical Chemistry, 2013)
The effects of the operating backpressure on PEM fuel cell reactions and performance are analyzed using both theoretical and semi-empirical approaches. The change in fuel cell operation backpressure can affect the reversible thermodynamic voltage, exchange current density of the electrode reactions, the membrane conductivity, as well as mass transfer limiting current densities. Backpressure can affect the fuel cell open circuit voltage (OCV) by affecting theoretical potential, mixed O2-Pt voltage drop as well as the H 2 crossover induced voltage drop. The magnitude of the fuel cell voltage change with backpressure in both electrode kinetic and mass transfer ranges is determined mainly by both the fuel cell reaction exchange current densities and the mass transfer limiting current densities. Theoretical modeling indicates that when the fuel cell is controlled at a low backpressure or backpressure range, the change in backpressure will lead to a larger fuel cell voltage change than that of a fuel cell controlled at a high backpressure range. Overall, an increase in the fuel cell backpressure will result in a performance enhancement such as higher open circuit voltage, and kinetic cell voltages at higher backpressures. However, negative effects such as high crossover, sealing problems, parasitic power losses, higher cost for compression and enlarged volume of the fuel cell system can occur with a higher operating backpressure. © 2012 Published by Elsevier B.V. All rights reserved.
Keywords: Back pressures; Exchange current densities; Gas partial pressure; Limiting current density; PEM fuel cell; Performance enhancements; Reversible thermodynamics; Semi-empirical approach; Current density; Electric conductivity; Kinetics; Mass transfer; Open circuit voltage; Reaction kinetics; Proton exchange membrane fuel cells (PEMFC)

Electron doping evolution of the magnetic excitations in BaFe 2-xNixAs2 - Luo, H.; Lu, X.; Zhang, R.; Wang, M.; Goremychkin, E.A.; Adroja, D.T.; Danilkin, S.; Deng, G.; Yamani, Z.; Dai, P. (Physical Review B - Condensed Matter and Materials Physics, 2013)
We use inelastic neutron scattering (INS) spectroscopy to study the magnetic excitations spectra throughout the Brillouin zone in electron-doped iron pnictide superconductors BaFe2-xNixAs2 with x=0.096,0.15,0.18. While the x=0.096 sample is near optimal superconductivity with Tc=20 K and has coexisting static incommensurate magnetic order, the x=0.15,0.18 samples are electron overdoped with reduced Tc of 14 and 8 K, respectively, and have no static antiferromagnetic (AF) order. In previous INS work on undoped (x=0) and electron optimally doped (x=0.1) samples, the effect of electron doping was found to modify spin waves in the parent compound BaFe2As2 below ∼100 meV and induce a neutron spin resonance at the commensurate AF ordering wave vector that couples with superconductivity. While the new data collected on the x=0.096 sample confirm the overall features of the earlier work, our careful temperature dependent study of the resonance reveals that the resonance suddenly changes its Q width below Tc similar to that of the optimally hole-doped iron pnictides Ba0.67K0.33Fe 2As2. In addition, we establish the dispersion of the resonance and find it to change from commensurate to transversely incommensurate with increasing energy. Upon further electron doping to overdoped iron pnictides with x=0.15 and 0.18, the resonance becomes weaker and transversely incommensurate at all energies, while spin excitations above ∼100 meV are still not much affected. Our absolute spin excitation intensity measurements throughout the Brillouin zone for x=0.096,0.15,0.18 confirm the notion that the low-energy spin excitation coupling with itinerant electron is important for superconductivity in these materials, even though the high-energy spin excitations are weakly doping dependent. © 2013 American Physical Society.

Multi-scale modeling and synthesis of polyester ionomers - Nikolić, D.; Moffat, K.A.; Farrugia, V.M.; Kobryn, A.E.; Gusarov, S.; Wosnick, J.H.; Kovalenko, A. (Physical Chemistry Chemical Physics, 2013)
Simulations of microphase separation are carried out using the dissipative particle dynamics (DPD). By varying the concentration and temperature of resin solutions we explore mesomorphologies supported by the all-atom models. We found that for a low degree of functionalization the homogeneously distributed ionomers self-assemble into spherical micelles at solid loads below 31 wt%, subject to the activation energy barrier for the gradual growth of pre-micellar aggregates. Computed optimum aggregation numbers exhibit sensitivity to both the temperature-dependent interfacial tension and the ionic content and compare well with the experimental observations. This journal is © the Owner Societies.

Avoided quantum criticality and magnetoelastic coupling in BaFe 2-xNixAs2 - Lu, X.; Gretarsson, H.; Zhang, R.; Liu, X.; Luo, H.; Tian, W.; Laver, M.; Yamani, Z.; Kim, Y.-J.; Nevidomskyy, A.H.; Si, Q.; Dai, P. (Physical Review Letters, 2013)
We study the structural and magnetic orders in electron-doped BaFe 2-xNixAs2 by high-resolution synchrotron x-ray and neutron scatterings. Upon Ni doping x, the nearly simultaneous tetragonal-to-orthorhombic structural (Ts) and antiferromagnetic (TN) phase transitions in BaFe2As2 are gradually suppressed and separated, resulting in Ts>TN with increasing x, as was previously observed. However, the temperature separation between Ts and TN decreases with increasing x for x≥0.065, tending toward a quantum bicritical point near optimal superconductivity at x≈0.1. The zero-temperature transition is preempted by the formation of a secondary incommensurate magnetic phase in the region 0.0882;0.104, resulting in a finite value of TN≈Tc+10 K above the superconducting dome around x≈0.1. Our results imply an avoided quantum critical point, which is expected to strongly influence the properties of both the normal and superconducting states. © 2013 American Physical Society.
Keywords: Antiferromagnetics; Magnetoelastic couplings; Quantum critical points; Quantum criticality; Superconducting state; Synchrotron x rays; Temperature separation; Zero temperatures; Antiferromagnetism; Separation; Superconductivity; Nickel

The nonlinear Rashba effect in Hg0.77Cd0.23Te inversion layers probed by weak antilocalization analysis - Liu, X. Z.; Yu, G.; Wei, L. M.; Lin, T.; Xu, Y. G.; Yang, J. R.; Wei, Y. F.; Guo, S. L.; Chu, J. H.; Rowell, N. L.; Lockwood, D. J. (Journal of Applied Physics, 2013)
The Rashba spin-orbit interaction of the two-dimensional electron gas with high mobility in the inversion layer of p-type Hg0.77Cd 0.23Te is investigated by magnetotransport measurements. Both the Rashba spin splitting and Rashba coefficient are extracted by analysis of the weak anti-localization effect using the Golub model. It is found that both the splitting and coefficient increase with increasing electron density (∼3.0-6.0 × 1015 m-2), i.e., with the gate voltage. A self-consistent Schrodinger-Poisson calculation is performed and suggests that the nonlinear Rashba effect caused by the weakening of interband coupling, especially at high electron density, dominates this system. © 2013 American Institute of Physics.
Keywords: Anti-localization effects; Gate voltages; High mobility; High-electron-density; Interband coupling; Magneto-transport measurement; P-type; Rashba effects; Rashba spin orbit interaction; Rashba spin splitting; Weak antilocalization; Carrier concentration; Electron density measurement; Electron gas; Inversion layers

The ACS LCID project. Ix. Imprints of the early universe in the radial variation of the star formation history of dwarf galaxies - Hidalgo, S.L.; Monelli, M.; Aparicio, A.; Gallart, C.; Skillman, E.D.; Cassisi, S.; Bernard, E.J.; Mayer, L.; Stetson, P.; Cole, A.; Dolphin, A. (The Astrophysical Journal, 2013)
Based on Hubble Space Telescope observations from the Local Cosmology from Isolated Dwarfs project, we present the star formation histories, as a function of galactocentric radius, of four isolated Local Group dwarf galaxies: two dSph galaxies, Cetus and Tucana, and two transition galaxies (dTrs), LGS-3 and Phoenix. The oldest stellar populations of the dSphs and dTrs are, within the uncertainties, coeval (∼13 Gyr) at all galactocentric radii. We find that there are no significative differences between the four galaxies in the fundamental properties (such as the normalized star formation rate or age-metallicity relation) of their outer regions (radii greater than four exponential scale lengths); at large radii, these galaxies consist exclusively of old (≳ 10.5 Gyr) metal-poor stars. The duration of star formation in the inner regions varies from galaxy to galaxy, and the extended central star formation in the dTrs produces the dichotomy between dSph and dTr galaxy types. The dTr galaxies show prominent radial stellar population gradients: The centers of these galaxies host young (≲ 1 Gyr) populations, while the age of the last formation event increases smoothly with increasing radius. This contrasts with the two dSph galaxies. Tucana shows a similar, but milder, gradient, but no gradient in age is detected Cetus. For the three galaxies with significant stellar population gradients, the exponential scale length decreases with time. These results are in agreement with outside-in scenarios of dwarf galaxy evolution, in which a quenching of the star formation toward the center occurs as the galaxy runs out of gas in the outskirts. © 2013. The American Astronomical Society. All rights reserved.

Effects of amino acid deletion and substitution on the chemical properties, biological activities of the frog peptide palustrin-OG1 - Xie, Y.-G.; Liu, Y.-F.; Luan, C.; Han, F.-F.; Lai, R.; Groleau, D.; Feng, J.; Wang, Y.-Z. (Protein and Peptide Letters, 2013)
Palustrin-OG1 (OG1) is a host defense peptide isolated from the frog Odorrana grahami. In this study, we analyzed the chemical properties, antimicrobial activities and cytotoxicities of OG1 and its derivatives to identify the most promising peptide as an antimicrobial agent. By increasing the net positive charge, amphipathicity and decreasing the mean hydrophobicity of OG1, the derivative named as OG2 exerted higher antimicrobial activity against bacteria but lower cytotoxicity against both porcine erythrocytes and peripheral blood mononuclear cells than did OG1 (P<0.01). After substitution of Cys residues of OG2 by Ala or Trp residues, two derivatives named as OG2A and OG2W were less effective against bacteria and induced greater hemolysis than did OG2, indicating the importance of Cys residues. The substitution of the C-terminal Thr of OG2 resulted OG2N, which decreased the cytotoxicity and improved killing kinetics against gram-positive bacteria by the rapid damage of cell wall and membrane. © 2013 Bentham Science Publishers.
Keywords: alanine; antiinfective agent; cysteine; OG1 peptide; OG2 peptide; OG2A peptide; OG2N peptide; OG2W peptide; tryptophan; unclassified drug; amino acid deletion; amino acid substitution; animal cell; article; bacterial cell wall; bacterial kinetics; bactericidal activity; biological activity; cell damage; controlled study; drug cytotoxicity; erythrocyte; Escherichia coli; hemolysis; hydrophobicity; membrane damage; minimum inhibitory concentration; nonhuman; peripheral blood mononuclear cell; protein function; protein modification; Pseudomonas aeruginosa; Salmonella enterica; Salmonella typhimurium; Staphylococcus aureus

Transparent anodic TiO2 nanotube arrays on plastic substrates for disposable biosensors and flexible electronics - Farsinezhad, S.; Mohammadpour, A.; Dalrymple, A.N.; Geisinger, J.; Kar, P.; Brett, M.J.; Shankar, K. (Journal of Nanoscience and Nanotechnology, 2013)
Exploitation of anodically formed self-organized TiO2 nanotube arrays in mass-manufactured, disposable biosensors, rollable electrochromic displays and flexible large-area solar cells would greatly benefit from integration with transparent and flexible polymeric substrates. Such integration requires the vacuum deposition of a thin film of titanium on the desired substrate, which is then anodized in suitable media to generate TiO2 nanotube arrays. However the challenges associated with control of Ti film morphology, nanotube array synthesis conditions, and film adhesion and transparency, have necessitated the use of substrate heating during deposition to temperatures of at least 300 °C and as high as 500 °C to generate highly ordered open-pore nanotube arrays, thus preventing the use of polymeric substrates. We report on a film growth technique that exploits atomic peening to achieve high quality transparent TiO2 nanotube arrays with lengths up to 5.1 μm at room temperature on polyimide substrates without the need for substrate heating or substrate biasing or a Kauffman ion source. The superior optical quality and uniformity of the nanotube arrays was evidenced by the high specular reflectivity and the smooth pattern of periodic interferometric fringes in the transmission spectra of the nanotube arrays, from which the wavelength-dependent effective refractive index was extracted for the air-TiO2 composite medium. A fluorescent immunoassay biosensor constructed using 5.1 μm-long transparent titania nanotube arrays (TTNAs) grown on Kapton substrates detected human cardiac troponin I at a concentration of 0.1 μg ml-1. Copyright © 2013 American Scientific Publishers.
Keywords: Anodizations; Metal oxides; Polymer substrate; Self-Organized; Thin-film depositions; Transparent; Troponin; Bioassay; Biosensors; Deposition; Film growth; Ion sources; Nanotubes; Polyimides; Polymeric films; Refractive index; Titanium; Titanium dioxide; Substrates; nanotube; plastic; titanium; titanium dioxide; article; chemistry; electronics; fluorescence; genetic procedures; immunoassay; Biosensing Techniques; Electronics; Fluorescence; Immunoassay; Nanotubes; Plastics; Titanium

Optimum extraction of polysaccharides from Opuntia dillenii and evaluation of its antioxidant activities - Yang, Q.; Chen, H.; Zhou, X.; Zhang, J. (Carbohydrate Polymers, 2013)
Response surface methodology (RSM) was applied to optimize the extraction of crude polysaccharides from Opuntia dillenii (Ker-Gaw) Haw. A three-level, four-variable Box-Behnken design was employed to obtain the best possible combination of extraction temperature (80-90°C), extraction time (50-70 min), number of extraction cycle (1-3 times), and ratio of water to raw material (8:1-12:1, v/w) for maximum yield of crude polysaccharide. Besides, the antioxidant capacity of crude polysaccharide was evaluated by DPPH assay. The results showed that optimized extraction conditions were extraction temperature 85°C, extraction time 63.7 min, extraction 2 times and ratio of water to raw material 11.14:1. Under these conditions, the experimental yield was 27.36 ± 0.21%, which is well in close agreement with the value (27.44%) predicted by RSM model. Pharmacological test showed that O. dillenii crude polysaccharides had a good antioxidant activity. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Anti-oxidant activities; Antioxidant capacity; Box-Behnken design; Extraction conditions; Extraction temperatures; Extraction time; Opuntia dillenii; Response surface methodology; Agents; Optimization; Polysaccharides; Surface properties; Extraction; Opuntia; Opuntia dillenii

Limb-specific emotional modulation of cervical spinal cord neurons - McIver, T.A.; Kornelsen, J.; Smith, S.D. (Cognitive, Affective and Behavioral Neuroscience, 2013)
Emotional stimuli receive prioritized attentional and motoric processing in the brain. Recent data have indicated that emotional stimuli enhance activity in the cervical spinal cord as well. In the present study, we used fMRI to investigate the specificity of this emotion-dependent spinal cord activity. We examined whether the limb depicted in a passively viewed image (upper vs. lower) differentially influenced activity in the cervical segments that innervate the upper limbs, and whether this effect was enhanced by emotion. Participants completed four fMRI runs: neutral-upper limb, neutral-lower limb, negative-upper limb, and negative-lower limb. The results indicated main effects of limb and emotion, with upper limbs and negative stimuli eliciting greater activity than lower limbs and neutral stimuli, respectively. For upper-limb runs, negative stimuli evoked more activity than did neutral stimuli. Additionally, negative stimuli depicting upper limbs produced stronger responses than did negative stimuli depicting lower limbs. These results suggest that emotional stimuli augment limb-specific responses in the spinal cord. © 2013 Psychonomic Society, Inc.

Water in star-forming regions with Herschel (WISH): III. Far-infrared cooling lines in low-mass young stellar objects - Karska, A.; Herczeg, G. J.; Van Dishoeck, E. F.; Wampfler, S. F.; Kristensen, L. E.; Goicoechea, J. R.; Visser, R.; Nisini, B.; San José-García, I.; Bruderer, S.; Śniady, P.; Doty, S.; et al. (Astronomy and Astrophysics, 2013)
Context.Understanding the physical phenomena involved in the earlierst stages of protostellar evolution requires knowledge of the heating and cooling processes that occur in the surroundings of a young stellar object. Spatially resolved information from its constituent gas and dust provides the necessary constraints to distinguish between different theories of accretion energy dissipation into the envelope. Aims. Our aims are to quantify the far-infrared line emission from low-mass protostars and the contribution of different atomic and molecular species to the gas cooling budget, to determine the spatial extent of the emission, and to investigate the underlying excitation conditions. Analysis of the line cooling will help us characterize the evolution of the relevant physical processes as the protostar ages. Methods.Far-infrared Herschel-PACS spectra of 18 low-mass protostars of various luminosities and evolutionary stages are studied in the context of the WISH key program. For most targets, the spectra include many wavelength intervals selected to cover specific CO, H2O, OH, and atomic lines. For four targets the spectra span the entire 55-200 μm region. The PACS field-of-view covers ∼47′′ with the resolution of 9.4′′. Results. Most of the protostars in our sample show strong atomic and molecular far-infrared emission. Water is detected in 17 out of 18 objects (except TMC1A), including 5 Class I sources. The high-excitation H2O 818-707 63.3 μm line (Eu/kB = 1071 K) is detected in 7 sources. CO transitions from J = 14-13 up to J = 49-48 are found and show two distinct temperature components on Boltzmann diagrams with rotational temperatures of ∼350 K and ∼700 K. H 2O has typical excitation temperatures of ∼150 K. Emission from both Class 0 and I sources is usually spatially extended along the outflow direction but with a pattern that depends on the species and the transition. In the extended sources, emission is stronger off source and extended on =10 000 AU scales; in the compact sample, more than half of the flux originates within 1000 AU of the protostar. The H2O line fluxes correlate strongly with those of the high-J CO lines, both for the full array and for the central position, as well as with the bolometric luminosity and envelope mass. They correlate less strongly with OH fluxes and not with [Oi] fluxes. In contrast, [Oi] andOH often peak together at the central position. Conclusions.The PACS data probe at least two physical components. The H2O and CO emission very likely arises in non-dissociative (irradiated) shocks along the outflow walls with a range of pre-shock densities. Some OH is also associated with this component, most likely resulting from H2O photodissociation. UV-heated gas contributes only a minor fraction to the CO emission observed by PACS, based on the strong correlation between the shock-dominated CO 24-23 line and the CO 14-13 line. [Oi] and some of the OH emission probe dissociative shocks in the inner envelope. The total far-infrared cooling is dominated by H2O and CO, with the fraction contributed by [Oi] increasing for Class I sources. Consistent with previous studies, the ratio of total far-infrared line emission over bolometric luminosity decreases with the evolutionary state
Keywords: infrared: ISM; ISM: jets and outflows; stars: protostars; molecular processes; astrochemistry

LIDAR and RADAR Observations - Pelon, J.; Vali, G.; Ancellet, G.; Ehret, G.; Flamant, P.H.; Haimov, S.; Heymsfield, G.; Leon, D.; Mead, J.B.; Pazmany, A.L.; Protat, A.; Wang, Z.; et al. (Airborne Measurements for Environmental Research: Methods and Instruments, 2013)

Feasibility study on grinding of titanium alloys with electroplated CBN wheels - Shi, Z.D.; Attia, H. (Advanced Materials Research, 2013)
An experimental investigation is reported on the grinding of a titanium alloy using electroplated CBN wheels with water-based grinding fluid and wheel surface cleaning fluid applied at high pressures. This work was motivated by applying grinding fluid and wheel surface cleaning fluid both at high pressures for avoiding wheel loading, which is commonly seen in titanium alloy grinding. The objective is to explore the feasibility to grind titanium alloys with electroplated CBN wheels and high pressure wheel surface cleaning fluid for enhancing material removal rates. Straight surface grinding experiments were conducted on titanium alloy blocks in both shallow depth of cut and creep-feed modes. Grinding power, forces, and surface roughness were measured. Specific material removal rates of 8 mm2/s in shallow cut mode and 3 mm2/s at a depth of cut as high as 3 mm in creep-feed mode were achieved without burning and smearing of ground surfaces. It was showed that it is feasible to grind titanium alloys with electroplated CBN wheels at enhanced removal rates by applying grinding and wheel cleaning fluid at high pressures. © (2013) Trans Tech Publications, Switzerland.
Keywords: Experimental investigations; Feasibility studies; Grinding fluids; Ground surfaces; Material removal rate; Specific materials; Surface grinding; Wheel cleaning; Abrasives; Creep; Grinding (machining); Loading; Surface cleaning; Surface roughness; Titanium alloys; Wheels

Defining the functional potential and active community members of a sediment microbial community in a high-arctic hypersaline subzero spring - Lay, C.-Y.; Mykytczuk, N.C.S.; Yergeau, É.; Lamarche-Gagnon, G.; Greer, C.W.; Whyte, L.G. (Applied and Environmental Microbiology, 2013)
The Lost Hammer (LH) Spring is the coldest and saltiest terrestrial spring discovered to date and is characterized by perennial discharges at subzero temperatures (-5°C), hypersalinity (salinity, 24%), and reducing (≈-165mV), microoxic, and oligotrophic conditions. It is rich in sulfates (10.0%, wt/wt), dissolved H2S/sulfides (up to 25ppm), ammonia (≈381μM), and methane (11.1g day-1). To determine its total functional and genetic potential and to identify its active microbial components, we performed metagenomic analyses of the LH Spring outlet microbial community and pyrosequencing analyses of the cDNA of its 16S rRNA genes. Reads related to Cyanobacteria (19.7%), Bacteroidetes (13.3%), and Proteobacteria (6.6%) represented the dominant phyla identified among the classified sequences. Reconstruction of the enzyme pathways responsible for bacterial nitrification/ denitrification/ammonification and sulfate reduction appeared nearly complete in the metagenomic data set. In the cDNA profile of the LH Spring active community, ammonia oxidizers (Thaumarchaeota), denitrifiers (Pseudomonas spp.), sulfate reducers (Desulfobulbus spp.), and other sulfur oxidizers (Thermoprotei) were present, highlighting their involvement in nitrogen and sulfur cycling. Stress response genes for adapting to cold, osmotic stress, and oxidative stress were also abundant in the metagenome. Comparison of the composition of the functional community of the LH Spring to metagenomes from other saline/ subzero environments revealed a close association between the LH Spring and another Canadian high-Arctic permafrost environment, particularly in genes related to sulfur metabolism and dormancy. Overall, this study provides insights into the metabolic potential and the active microbial populations that exist in this hypersaline cryoenvironment and contributes to our understanding of microbial ecology in extreme environments. © 2013, American Society for Microbiology.
Keywords: Metagenomic analysis; Microbial communities; Microbial components; Microbial populations; Oligotrophic conditions; Permafrost environment; Stress response genes; Sub-zero temperatures; Ammonia; Genes; Metabolism; Methane; Microorganisms; RNA; Sulfur; Sulfur compounds; complementary DNA; primer DNA; RNA 16S; adaptation; discharge; environmental stress; enzyme activity; fluvial deposit; genetic analysis; hypersaline environment; metabolism; microbial community; nutrient cycling; oxidation; population structure; terrestrial ecosystem; archaeon; Arctic; article; Bacteroidetes; cold; cyanobacterium; DNA sequence; genetics; metagenome; microbiology; molecular genetics; natural spring; nucleotide sequence; Proteobacteria; salinity; sediment; Archaea; Arctic Regions; Bacteroidetes; Base Sequence; Cold Temperature; Cyanobacteria; DNA Primers; DNA, Complementary; Geologic Sediments; Metagenome; Molecular Sequence Data; Natural Springs; Proteobacteria; RNA, Ribosomal, 16S; Salinity; Sequence Analysis, DNA; Canada

Electrochemical behavior of nanostructured nickel phthalocyanine (NiPc/C) for oxygen reduction reaction in alkaline media - Ding, L.; Xin, Q.; Zhou, X.; Qiao, J.; Li, H.; Wang, H. (Journal of Applied Electrochemistry, 2013)
Carbon-supported nickel phthalocyanine (NiPc/C) nanoparticle catalysts have been synthesized by a simple solvent-impregnation and milling procedure, then heat-treated at 600, 700, 800 and 900 °C to optimize their activity for the oxygen reduction reaction (ORR). The electrocatalytic activity and electron transfer mechanism of NiPc/C catalysts were demonstrated in oxygen-saturated alkaline electrolyte by cyclic voltammetry, linear sweep voltammetry as well as rotating disk electrode techniques, respectively. The results show that the heat-treatment temperature has a remarkable impact on the ORR activity of NiPc/C. An onset potential of 0.05 V and a half-wave potential of -0.15 V are achieved in 0.1 M KOH after the catalyst was heat-treated at 800 °C. In addition to an increase in ORR kinetics, the number of electrons transferred for ORR also increased from 2.2 to 2.8 with increasing heat-treatment temperature from 600 to 800 °C. To understand the heat-treatment effect, X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS) were used to identify the catalyst structure and composition. From XPS analysis, pyridinic-N and graphitic-N were clearly observed after the sample was heat-treated at 800 °C. Both of these species might be assigned to sites catalytically active toward the ORR leading to activity enhancement. © 2012 Springer Science+Business Media Dordrecht.
Keywords: Activity enhancement; Alkaline electrolytes; Alkaline media; Catalyst structures; Electrocatalytic activity; Electrochemical behaviors; Electron transfer mechanisms; Half-wave potential; Heat treatment temperature; Heat-treatment effects; Linear sweep voltammetry; Milling procedures; Nano-structured; Nanoparticle catalysts; Nickel phthalocyanines; Number of electrons; Onset potential; Oxygen reduction reaction; Remarkable impact; Rotating disk electrodes; XPS analysis; Catalysts; Cyclic voltammetry; Electrolytes; Electrolytic reduction; Electron transitions; Nitrogen compounds; Photoelectrons; Proton exchange membrane fuel cells (PEMFC); Rotating disks; Synthesis (chemical); Thermogravimetric analysis; Transmission electron microscopy; X ray diffraction; X ray photoelectron spectroscopy; Nickel

Collapsin response mediator protein 3 deacetylates histone H4 to mediate nuclear condensation and neuronal death - Hou, S.T.; Jiang, S.X.; Aylsworth, A.; Cooke, M.; Zhou, L. (Scientific Reports, 2013)
CRMP proteins play critical regulatory roles during semaphorin-mediated neurite outgrowth, neuronal differentiation and death. Albeit having a high degree of structure and sequence resemblance to that of liver dihydropyrimidinase, purified rodent brain CRMPs do not hydrolyze dihydropyrimidinase substrates. Here we found that mouse CRMP3 has robust histone H4 deacetylase activity. During excitotoxicity-induced mouse neuronal death, calpain-cleaved, N-terminally truncated CRMP3 undergoes nuclear translocation to cause nuclear condensation through deacetylation of histone H4. CRMP3-mediated deacetylation of H4 leads to de-repression of the E2F1 gene transcription and E2F1-dependent neuronal death. These studies revealed a novel mechanism of CRMP3 in neuronal death. Together with previous well established bodies of literature that inhibition of histone deacetylase activity provides neuroprotection, we envisage that inhibition of CRMP3 may represent a novel therapeutic approach towards excitotoxicity-induced neuronal death.
Keywords: Dpysl4 protein, mouse; glutamic acid; histone; histone deacetylase; nerve protein; transcription factor E2F1; tubulin; acetylation; animal; article; cell death; cell line; cell nucleus; drug effect; female; gene expression regulation; gene silencing; genetics; human; metabolism; mouse; nerve cell; protein binding; protein transport; ultrastructure; Acetylation; Animals; Cell Death; Cell Line; Cell Nucleus; E2F1 Transcription Factor; Female; Gene Expression Regulation; Gene Knockdown Techniques; Glutamic Acid; Histone Deacetylases; Histones; Humans; Mice; Nerve Tissue Proteins; Neurons; Protein Binding; Protein Transport; Tubulin

Maintaining health by balancing microbial exposure and prevention of infection: The hygiene hypothesis versus the hypothesis of early immune challenge - Kramer, A.; Bekeschus, S.; Bröker, B.M.; Schleibinger, H.; Razavi, B.; Assadian, O. (Journal of Hospital Infection, 2013)
The human immune system is inseparably bonded to an individual's personal micro-biome from birth to death. Since the beginning of life, commensal relationships have ensured the survival of micro- and macro-organisms within complex relationships. However, technological advances and altered lifestyle imposed new rules for this interaction during recent decades. It has been observed that reduced exposure to micro-organisms and parasites results in decreased morbidity and mortality, but is also associated with a rising prevalence of atopic disorders and autoimmune diseases, mostly in industrialized countries. This inverse relationship is described by the 'hygiene hypothesis', put forward in 1989, yet this term only imperfectly describes these observations, as excessive hygiene or hygienic measures may not directly be the central cause. The lack of appropriate immune stimulation during early childhood with the consequence of disturbed alignment in the sequence of encountering self- or non-self-antigens might account in the rise of atopy and autoimmune disease. For this reason we propose the term 'early immune challenge hypothesis'. This concept highlights the importance of immune priming in early life in the context of genetic, social, geographic, cultural, and economic background. Moreover, it emphasizes the central role of 'training' of regulatory T-cells through sufficient microbial exposure, leading to a robust, healthy balance between inflammation and anti-inflammation or immune tolerance. Insufficient exposure might result in abnormal immune regulatory development. Finally, it incorporates the idea of encountering 'old friends' - organisms that shaped our immune system during human phylogeny. This article gives a comprehensive overview of the relationship between microbial exposure, and the incidence of asthma and hay fever is outlined. Although the outcomes of these studies originally were interpreted in the framework of the hygiene hypothesis, they may suit the concept of the hypothesis of early immune challenge even better. Moreover, recent studies have revealed that TH or TReg imbalances in disease may be partially corrected by the administration of helminthic or bacterial extracts. © 2013 The Healthcare Infection Society.
Keywords: antiinflammatory activity; article; asthma; atopy; autoimmune disease; bacterial flora; Crohn disease; cross infection; early immune challenge hypothesis; enteritis; exposure; hay fever; Helicobacter infection; Heligmosomoides polygyrus; helper cell; host parasite interaction; host pathogen interaction; human; hygiene hypothesis; hypothesis; immune response; immunological tolerance; immunoregulation; immunostimulation; infection; infection prevention; inflammation; innate immunity; microbial colonization; microorganism; nonhuman; parasite; phylogeny; regulatory T lymphocyte; Schistosoma; Schistosoma mansoni; Th1 cell; Th17 cell; Toxoplasma gondii; Trichuris suis; Autoimmune Diseases; Health; Humans; Hygiene Hypothesis; Hypersensitivity; Incidence

Freeform Laser Consolidated H13 and CPM 9V Tool Steels - Xue, L.; Chen, J.; Wang, S.-H. (Metallography, Microstructure, and Analysis, 2013)
As a novel computer-aided materials additive manufacturing process, the freeform laser consolidation (LC) can directly produce functional shapes (features or structures) through a "layer-upon-layer" deposition. In this research, LC processability of both H13 and CPM 9V tool steels and their mechanical performance thus obtained were investigated. Both laser-consolidated tool steels were metallurgically sound with no crack, exhibiting layer-wise refined solidified structures with dominated martensite and small amount of retained austenite, as well as composition-dependent carbides. Laser-consolidated H13 could outperform its wrought counterpart mechanically as measured by tensile strength/strain, and bonding strength as well as sliding wear resistance; laser-consolidated CPM 9V could provide excellent sliding wear resistance superior to the conventional widely used tool steel (such as wrought D2). These unique microstructures and mechanical properties could be tailored for niche applications in additive manufacturing of tools, molds, and dies. © 2013 Her Majesty the Queen in Right of Canada.
Keywords: Additive Manufacturing; AISI H13; CPM 9V; Freeforms; Rapid tooling; Carbides; Manufacture; Wear resistance; Tool steel

Initial thickness measurements and insights into crystal growth of methane hydrate film - Li, S.-L.; Sun, C.-Y.; Liu, B.; Feng, X.-J.; Li, F.-G.; Chen, L.-T.; Chen, G.-J. (AIChE Journal, 2013)
The initial thickness of methane hydrate film was directly measured by suspending a single methane bubble in water at 274.0, 276.0, and 278.0 K. The results show that the initial hydrate film thickness decreases from tens of micrometers to about 10 μm with the subcooling increased from 0.5 K to about 3 K. When subcooling is higher than 1.0 K, all initial film thickness data measured under different temperatures vary inversely with the subcooling. Notable three-dimensional growths of hydrate crystals of different sizes and shapes at film front and emergence of new crystal were clearly observed at lower subcooling that resulting in the rougher surface of hydrate film and uncertainty of initial thickness measurement under lower subcooling. The hydrate film growth was dominated by film growth in thickness, not by lateral growth at low subcooling. The growth in thickness of hydrate shell covering one whole bubble surface was also investigated. © 2013 American Institute of Chemical Engineers (AIChE).
Keywords: Bubble in waters; Bubble surface; Different sizes; Hydrate shells; Initial thickness; Lateral growth; Methane hydrates; Three-dimensional growth; Crystal growth; Film thickness; Gas hydrates; Hydration; Methane; Thickness gages; Thickness measurement; Three dimensional; Film growth

Effects of thioredoxin: Sumo and intein on soluble fusion expression of an antimicrobial peptide OG2 in escherichia coli - Xie, Y.-G.; Luan, C.; Zhang, H.-W.; Han, F.-F.; Feng, J.; Choi, Y-J.; Groleau, D.; Wang, Y.-Z. (Protein and Peptide Letters, 2013)
OG2 is a modified antimicrobial peptide of Palustrin-OG1 (OG1), which is derived from Odorrana grahami frog. OG2 has shown much higher selective antimicrobial activity and lower hemolytic activity than OG1, indicating OG2 may be a promising antimicrobial agent. In this study, we investigated three fusion partners, including thioredoxin, Mxe GyrA intein, and small ubiquitin-like modifier (SUMO), each fused with OG2, and examined their effects on the expression level and solubility of OG2 in Escherichia coli. The codon-optimized OG2 gene was cloned into pET32a (+) and pTWIN1 for fusion with thioredoxin and Mxe GyrA intein, respectively. In addition, the SUMO-OG2 gene was amplified by splice overlap extension PCR method and was cloned into pET30a (+). All recombinant plasmids were then transformed into E. coli BL21(DE3)pLysS, and the expressed fusion proteins were verified. Upon isopropyl α-D-1- thiogalactopyranoside (IPTG) induction, OG2 fused with thioredoxin (Trx-OG2) showed the highest yield as a soluble fusion protein (50 mg/L), followed by Mxe GyrA intein (44 mg/L) and SUMO (11 mg/L). The thioredoxin-fused protein (Trx-OG2) was then purified by nickel-nitrilotriacetic acid chromatography and desalted by Sephadex G25. The OG2 released by both tobacco etch virus protease and enterokinase from Trx-OG2 showed strong antimicrobial activity against Staphylococcus aureus ATCC25923. Copyright © 2012 Bentham Science Publishers. All Rights Reserved.
Keywords: intein; polypeptide antibiotic agent; polypeptide antibiotic agent OG2; SUMO protein; thioredoxin; unclassified drug; affinity chromatography; article; chemical structure; controlled study; enzyme release; Escherichia coli; expression vector; hemolysis; molecular cloning; nonhuman; polymerase chain reaction; process optimization; protein expression; protein purification; Animals; Anti-Infective Agents; Antimicrobial Cationic Peptides; Erythrocytes; Escherichia coli; Hemolytic Agents; Inteins; Ranidae; Recombinant Fusion Proteins; Small Ubiquitin-Related Modifier Proteins; Staphylococcus aureus; Swine; Thioredoxins

Redshift 6.4 host galaxies of 108 solar mass black holes: Low star formation rate and dynamical mass - Willott, C.J.; Omont, A.; Bergeron, J. (The Astrophysical Journal, 2013)
We present Atacama Large Millimeter Array observations of rest-frame far-infrared continuum and [C II] line emission in two z = 6.4 quasars with black hole masses of 108 M ⊙. CFHQS J0210-0456 is detected in the continuum with a 1.2 mm flux of 120 ± 35 μJy, whereas CFHQS J2329-0301 is undetected at a similar noise level. J2329-0301 has a star formation rate limit of <40 M ⊙ yr-1, considerably below the typical value at all redshifts for this bolometric luminosity. Through comparison with hydro simulations, we speculate that this quasar is observed at a relatively rare phase where quasar feedback has effectively shut down star formation in the host galaxy. [C II] emission is also detected only in J0210-0456. The ratio of [C II] to far-infrared luminosity is similar to that of low-redshift galaxies of comparable luminosity, suggesting that the previous finding of an offset in the relationships between this ratio and far-infrared luminosity at low and high redshifts may be partially due to a selection effect due to the limited sensitivity of previous continuum data. The [C II] line of J0210-0456 is relatively narrow (FWHM = 189 ± 18 km s-1), indicating a dynamical mass substantially lower than expected from the local black hole-velocity dispersion correlation. The [C II] line is marginally resolved at 0.″7 resolution with the blue and red wings spatially offset by 0.″5 (3 kpc) and a smooth velocity gradient of 100 km s-1 across a scale of 6 kpc, possibly due to the rotation of a galaxy-wide disk. These observations are consistent with the idea that stellar mass growth lags black hole accretion for quasars at this epoch with respect to more recent times. © 2013. The American Astronomical Society. All rights reserved.

Compressed sensing reconstruction improves sensitivity of variable density spiral fMRI - Holland, D.J.; Liu, C.; Song, X.; Mazerolle, E.L.; Stevens, M.T.; Sederman, A.J.; Gladden, L.F.; D'Arcy, R.C.N.; Bowen, C.V.; Beyea, S.D. (Magnetic Resonance in Medicine, 2013)
Purpose Functional MRI (fMRI) techniques that can provide excellent blood oxygen level dependent contrast, rapid whole brain imaging, and minimal spatial distortion are in demand. This study explored whether fMRI sensitivity can be improved through the use of compressed sensing (CS) reconstruction of variable density spiral fMRI. Methods Three different CS-reconstructed 1-shot variable density spirals were explored (corresponding to 28%, 35%, and 46% under-sampling), and compared with conventional 1-shot and 2-shot Archimedean spirals acquired using matched echo time and volume repetition time. fMRI maps were reconstructed with or without CS MRI and sensitivity was compared using identically matched voxels. Results The results demonstrated that an l 1-norm based CS reconstruction only led to an increase in functional contrast when applied to 28% under-sampled data. A whole brain t-contrast map revealed that 2-shot uniformly sampled spiral and 28% under-sampled spiral data reconstructed with CS yield equivalent sensitivity, even with matched echo time and volume repetition time Conclusion VD spiral exhibits a useful operating range, in the region of 25-30% under-sampling, for which CS reconstruction can be used to increase the sensitivity of fMRI to brain activity. Using CS, VD acquisitions achieve the same sensitivity as 2-shot Archimedean acquisitions, but require only a single shot. Magn Reson Med 70:1634-1643, 2013. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc.

The very young type Ia supernova 2013dy: Discovery, and strong carbon absorption in early-time spectra - Zheng, W.; Silverman, J.M.; Filippenko, A.V.; Kasen, D.; Nugent, P.E.; Graham, M.; Wang, X.; Valenti, S.; Ciabattari, F.; Kelly, P.L.; Fox, O.D.; Shivvers, I.; et al. (The Astrophysical Journal Letters, 2013)
The Type Ia supernova (SN Ia) 2013dy in NGC 7250 (d ≈ 13.7 Mpc) was discovered by the Lick Observatory Supernova Search. Combined with a prediscovery detection by the Italian Supernova Search Project, we are able to constrain the first-light time of SN 2013dy to be only 0.10 ± 0.05 days (2.4 ± 1.2 hr) before the first detection. This makes SN 2013dy the earliest known detection of an SN Ia. We infer an upper limit on the radius of the progenitor star of R 0 ≲ 0.25 R ⊙, consistent with that of a white dwarf. The light curve exhibits a broken power law with exponents of 0.88 and then 1.80. A spectrum taken 1.63 days after first light reveals a C II absorption line comparable in strength to Si II. This is the strongest C II feature ever detected in a normal SN Ia, suggesting that the progenitor star had significant unburned material. The C II line in SN 2013dy weakens rapidly and is undetected in a spectrum 7 days later, indicating that C II is detectable for only a very short time in some SNe Ia. SN 2013dy reached a B-band maximum of MB = -18.72 ± 0.03 mag ∼17.7 days after first light. © 2013. The American Astronomical Society. All rights reserved.

Effect of template size on the synthesis of mesoporous carbon spheresand their supported Fe-based ORR electrocatalysts - Zhang, L.; Kim, J.; Dy, E.; Ban, S.; Tsay, K.-C.; Kawai, H.; Shi, Z.; Zhang, J. (Electrochimica Acta, 2013)
Three mesoporous carbon spheres (MPCs) are synthesized using three different templates with sizes of22, 35 and 50 nm, respectively. These three MPC materials are then used as catalyst supports to formthree catalysts (Fe-N X/MPC22, Fe-NX/MPC35, and Fe-NX/MPC50) for oxygen reduction reaction (ORR).SEM images show that after catalyst deposition on the synthesized mesoporous carbon, the sphericalmorphology of mesoporous carbon is well maintained. EDX measurements show that the average Fecontent in the formed mesoporous carbon supported catalysts is very close to the initial synthesis valueof 5 wt%. BET and linear scanning voltammetry are used for characterizing the surface area and electro-chemical properties of the synthesized MPC support materials to study the effect of template size (orpore size). The results show that mesoporous carbon with template size of 50 nm has the largest BETsurface area (2125 m2/g). The measurement results show that all ORR activities of these three MPC sup-ported catalysts are higher than that of commercially available carbon supported one, demonstratingthe advantage of MPC support. Among these three catalysts, the performance order is Fe-N X/MPC50 > Fe-NX/MPC35 > Fe-NX/MPC22, showing the effect of template size on the ORR activity of the catalyst, i.e., theORR activity increases when the template size (or MPC pore size) is increased. The results also clearlyindicate that the mesopores in the range of 22-50 nm can still affect the ORR activity, suggesting thatmesopores are also important in the formation of ORR active sites besides micropores. © 2013 Published by Elsevier Ltd.
Keywords: Catalyst deposition; Mesoporous carbon; Mesoporous carbon supports; ORR electrocatalysts; Oxygen reduction reaction; Support materials; Template effects; Ultrasonic spray pyrolysis; Carbon; Catalyst activity; Catalyst supports; Electrocatalysts; Electrolytic reduction; Model predictive control; Proton exchange membrane fuel cells (PEMFC); Spray pyrolysis; Synthesis (chemical); Mesoporous materials

Adenosine monophosphate forms ordered arrays in multilamellar lipid matrices: insights into assembly of nucleic acid for primitive life - Toppozini, L.; Dies, H.; Deamer, D. W.; Rheinstädter, M. C. (PLoS ONE, 2013)
A fundamental question of biology is how nucleic acids first assembled and then were incorporated into the earliest forms of cellular life 4 billion years ago. The polymerization of nucleotides is a condensation reaction in which phosphodiester bonds are formed. This reaction cannot occur in aqueous solutions, but guided polymerization in an anhydrous lipid environment could promote a non-enzymatic condensation reaction in which oligomers of single stranded nucleic acids are synthesized. We used X-ray scattering to investigate 5′-adenosine monophosphate (AMP) molecules captured in a multilamellar phospholipid matrix composed of dimyristoylphosphatidylcholine. Bragg peaks corresponding to the lateral organization of the confined AMP molecules were observed. Instead of forming a random array, the AMP molecules are highly entangled, with the phosphate and ribose groups in close proximity. This structure may facilitate polymerization of the nucleotides into RNA-like polymers.
Keywords: adenosine phosphate; dimyristoylphosphatidylcholine; nucleic acid; phosphate; ribose; Bragg peak; crystal structure; mathematical phenomena; molecular biology; molecule lateral organization; multilamellar phospholipid matrix; nucleic acid assembly; nucleic acid structure; nucleic acid structure, metabolism and function; phospholipid bilayer; polymerization; radiation scattering; structure analysis

Antioxidant canolol production from a renewable feedstock via an engineered decarboxylase - Morley, Krista L.; Grosse, Stephan; Leisch, Hannes; Lau, Peter C. K. (Green Chemistry, 2013)
Canolol (4-vinylsyringol, VS), a potent antioxidant and an alkylperoxyl radical scavenger originally discovered in crude canola oil (rapeseed), is produced by decarboxylation of sinapic acid (SA) during canola seed roasting. Chemical syntheses of VS from SA require thermal or microwave induced decarboxylation in the presence of a base. A laboratory-evolved enzyme, designated SA decarboxylase (SAD), was developed in this study. In a biphasic bioreactor system, SAD was shown to produce VS from SA extracts prepared from canola meal with an overall yield of 3.0 mg VS per g of canola meal. In addition, we investigated the application of VS in polymerization to produce polyvinylsyringol (PVS) as a potential biodegradable polymer. The characteristics of PVS determined by thermogravimetric analysis, differential scanning calorimetry and nanoindentation tests are described. © 2013 The Royal Society of Chemistry.

Ecotoxicological assessment of a high energetic and insensitive munitions compound : 2,4-Dinitroanisole (DNAN) - Dodard, Sabine G.; Sarrazin, Manon; Hawari, Jalal; Paquet, Louise; Ampleman, Guy; Thiboutot, Sonia; Sunahara, Geoffrey I. (Journal of Hazardous Materials, 2013)
The high explosive nitroaromatic 2,4-dinitroanisole (DNAN) is less shock sensitive than 2,4,6-trinitrotoluene (TNT), and is proposed as a TNT replacement for melt-cast formulations. Before using DNAN in munitions and potentially leading to environmental impact, the present study examines the ecotoxicity of DNAN using selected organisms. In water, DNAN decreased green algae Pseudokirchneriella subcapitata growth (EC50=4.0mg/L), and bacteria Vibrio fischeri bioluminescence (Microtox, EC50=60.3mg/L). In soil, DNAN decreased perennial ryegrass Lolium perenne growth (EC50=7mg/kg), and is lethal to earthworms Eisenia andrei (LC50=47mg/kg). At sub-lethal concentrations, DNAN caused an avoidance response (EC50=31mg/kg) by earthworms. The presence of DNAN and 2-amino-4-nitroanisole in earthworms and plants suggested a role of these compounds in DNAN toxicity. Toxicity of DNAN was compared to TNT, tested under the same experimental conditions. These analyses showed that DNAN was equally, or even less deleterious to organism health than TNT, depending on the species and toxicity test. The present studies provide baseline toxicity data to increase the understanding of the environmental impact of DNAN, and assist science-based decision makers for improved management of potential DNAN contaminated sites. © 2013.
Keywords: 2 ,4 ,6-trinitrotoluene; 2 ,4-dinitroanisole; Ecotoxicity; Ecotoxicological assessment; Environmental risk assessment; Experimental conditions; Microtox; Pseudokirchneriella subcapitata; Algae; Ammunition; Aromatic compounds; Environmental impact; Explosives; Risk assessment; Toxicity; 2,4 dinitroanisole; aromatic nitro compound; nitrobenzene derivative; unclassified drug; bacterium; bioluminescence; concentration (composition); decision making; dose-response relationship; earthworm; ecotoxicology; environmental impact; environmental risk; grass; green alga; risk assessment; toxicity test; trinitrotoluene; algal growth; article; avoidance behavior; bioavailability; bioluminescence; biotransformation; concentration response; earthworm; ecotoxicity; Eisenia andrei; environmental impact; fluid balance; growth inhibition; nonhuman; oxidative phosphorylation; perennial ryegrass; Pseudokirchneriella subcapitata; Vibrio fischeri

Texture based segmentation method to detect atherosclerotic plaque from optical tomography images - Prakash, A.; Hewko, M.; Sowa, M.; Sherif, S. (Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 2013)
Optical coherence tomography (OCT) imaging has been widely employed in assessing cardiovascular disease. Atherosclerosis is one of the major cause cardio vascular diseases. However visual detection of atherosclerotic plaque from OCT images is often limited and further complicated by high frame rates. We developed a texture based segmentation method to automatically detect plaque and non plaque regions from OCT images. To verify our results we compared them to photographs of the vascular tissue with atherosclerotic plaque that we used to generate the OCT images. Our results show a close match with photographs of vascular tissue with atherosclerotic plaque. Our texture based segmentation method for plaque detection could be potentially used in clinical cardiovascular OCT imaging for plaque detection. © OSA-2013 SPIE.
Keywords: atherosclerosis; Atherosclerotic plaque; Cardio-vascular disease; High frame rate; plaque; Plaque detection; Texture-based segmentations; Visual detection; Diseases; Image processing; Image segmentation; Image texture; Photography; Textures; Tissue; Optical tomography

Evaluating the pathogenic potential of environmental Escherichia coli by using the caenorhabditis elegans infection model - Merkx-Jacques, A.; Coors, A.; Brousseau, R.; Masson, L.; Mazza, A.; Tien, Y.-C.; Topp, E. (Applied and Environmental Microbiology, 2013)
The detection and abundance of Escherichia coli in water is used to monitor and mandate the quality of drinking and recreational water. Distinguishing commensal waterborne E. coli isolates from those that cause diarrhea or extraintestinal disease in humans is important for quantifying human health risk. A DNA microarray was used to evaluate the distribution of virulence genes in 148 E. coli environmental isolates from a watershed in eastern Ontario, Canada, and in eight clinical isolates. Their pathogenic potential was evaluated with Caenorhabditis elegans, and the concordance between the bioassay result and the pathotype deduced by genotyping was explored. Isolates identified as potentially pathogenic on the basis of their complement of virulence genes were significantly more likely to be pathogenic to C. elegans than those determined to be potentially nonpathogenic. A number of isolates that were identified as nonpathogenic on the basis of genotyping were pathogenic in the infection assay, suggesting that genotyping did not capture all potentially pathogenic types. The detection of the adhesin-encoding genes sfaD, focA, and focG, which encode adhesins; of iroN2, which encodes a siderophore receptor; of pic, which encodes an autotransporter protein; and of b1432, which encodes a putative transposase, was significantly associated with pathogenicity in the infection assay. Overall, E. coli isolates predicted to be pathogenic on the basis of genotyping were indeed so in the C. elegans infection assay. Furthermore, the detection of C. elegans-infective environmental isolates predicted to be nonpathogenic on the basis of genotyping suggests that there are hitherto-unrecognized virulence factors or combinations thereof that are important in the establishment of infection. © 2013, American Society for Microbiology.
Keywords: Caenorhabditis elegans; Clinical isolates; Environmental isolates; Human health risks; Pathogenic potential; Recreational water; Siderophore receptors; Virulence factors; Bioassay; Encoding (symbols); Genes; Plants (botany); Potable water; Escherichia coli; virulence factor; abundance; bioassay; commensal; detection method; diarrheal disease; digestive system disorder; fecal coliform; gene expression; health risk; infectious disease; nematode; pathogen; protein; virulence; water quality; watershed; animal; animal model; article; Caenorhabditis elegans; Canada; DNA microarray; Escherichia coli; Escherichia coli infection; genetics; genotype; human; isolation and purification; microarray analysis; microbiology; mortality; pathogenicity; survival; Animals; Caenorhabditis elegans; Environmental Microbiology; Escherichia coli; Escherichia coli Infections; Genotype; Humans; Microarray Analysis; Models, Animal; Oligonucleotide Array Sequence Analysis; Ontario; Survival Analysis; Virulence Factors; Canada; Ontario [Canada]; Caenorhabditis elegans; Escherichia coli

Identification of genes involved in the biosynthesis of the third and fourth sugars of the Methanococcus maripaludis archaellin N-linked tetrasaccharide - Ding, Y.; Jones, G.M.; Uchida, K.; Aizawa, S.-I.; Robotham, A.; Logan, S.M.; Kelly, J.; Jarrell, K.F. (Journal of Bacteriology, 2013)
N-glycosylation is a protein posttranslational modification found in all three domains of life. Many surface proteins in Archaea, including S-layer proteins, pilins, and archaellins (archaeal flagellins) are known to contain N-linked glycans. In Methanococcus maripaludis, the archaellins are modified at multiple sites with an N-linked tetrasaccharide with the structure Sug-1,4-β-ManNAc3NAmA6Thr-1,4-β-GlcNAc3NAcA-1,3-β-GalNAc, where Sug is the unique sugar (5S)-2-acetamido-2,4-dideoxy-5-Omethyl-α-L-erythro-hexos-5-ulo-1,5-pyranose. In this study, four genes-mmp1084, mmp1085, mmp1086, and mmp1087-were targeted to determine their potential involvement of the biosynthesis of the sugar components in the N-glycan, based on bioinformatics analysis and proximity to a number of genes which have been previously demonstrated to be involved in the N-glycosylation pathway. The genes mmp1084 to mmp1087 were shown to be cotranscribed, and in-frame deletions of each gene as well as a Δmmp1086Δmmp1087 double mutant were successfully generated. All mutants were archaellated and motile. Mass spectrometry examination of purified archaella revealed that in Δmmp1084 mutant cells, the threonine linked to the third sugar of the glycan was missing, indicating a putative threonine transferase function of MMP1084. Similar analysis of the archaella of the Δmmp1085 mutant cells demonstrated that the glycan lacked the methyl group at the C-5 position of the terminal sugar, indicating that MMP1085 is a methyltransferase involved in the biosynthesis of this unique sugar. Deletion of the remaining two genes, mmp1086 and mmp1087, either singularly or together, had no effect on the structure of the archaellin N-glycan. Because of their demonstrated involvement in the N-glycosylation pathway, we designated mmp1084 as aglU and mmp1085 as aglV. © 2013, American Society for Microbiology.
Keywords: carbohydrate; methyltransferase; article; bioinformatics; biosynthesis; controlled study; gene; gene deletion; gene identification; glycosylation; mass spectrometry; Methanococcus maripaludis; mmp1084 gene; mmp1085 gene; mmp1086 gene; mmp1087 gene; nonhuman; priority journal; Archaeal Proteins; Carbohydrate Sequence; Computational Biology; Gene Deletion; Genes, Archaeal; Glycosylation; Mass Spectrometry; Membrane Proteins; Methanococcus; Methyltransferases; Multigene Family; Polysaccharides; Protein Processing, Post-Translational; Reverse Transcriptase Polymerase Chain Reaction; Threonine; Transferases

A 3D meso-scale analysis of angle-ply laminates - Zhang, Y.; Xia, Z.; Ellyin, F. (Mechanics of Advanced Materials and Structures, 2013)
A 3D two-cell representation of laminates with periodic fiber arrays is established and the corresponding periodic boundary conditions are presented. The matrix is described by a nonlinear viscoelastic material model and the fiber by an elastic one. Matrix cracking is modeled by a "smeared crack" method. The modeling of material nonlinearity, crack initiation, and growth, with appropriate periodic boundary conditions, are incorporated into a finite element model (FEM). Numerical results for five different angle-ply laminates under tensile loading are presented. The results are found to be in fair agreement with the available test data. © 2013 Taylor and Francis Group, LLC.
Keywords: Angle ply laminate; damage; Material non-linearity; Mesomechanics; Nonlinear viscoelastic material; Numerical results; Periodic boundary conditions; Smeared crack; Boundary conditions; Composite materials; Cracks; Finite element method; Three dimensional; Viscoelasticity; Laminates

Structure of a sugar N -formyltransferase from campylobacter jejuni - Thoden, J.B.; Goneau, M.-F.; Gilbert, M.; Holden, H.M. (Biochemistry, 2013)
The O-antigens, which are components of the outer membranes of Gram-negative bacteria, are responsible for the wide species variations seen in nature and are thought to play a role in bacterial virulence. They often contain unusual dideoxysugars such as 3,6-dideoxy-3-formamido-d-glucose (Qui3NFo). Here, we describe a structural and functional investigation of the protein C8J-1081 from Campylobacter jejuni 81116, which is involved in the biosynthesis of Qui3NFo. Specifically, the enzyme, hereafter referred to as WlaRD, catalyzes the N-formylation of dTDP-3,6-dideoxy-3-amino-d-glucose (dTDP-Qui3N) using N10-formyltetrahydrofolate as the carbon source. For this investigation, seven X-ray structures of WlaRD, in complexes with various dTDP-linked sugars and cofactors, were determined to resolutions of 1.9 Å or better. One of the models, with bound N10-formyltetrahydrofolate and dTDP, represents the first glimpse of an N-formyltransferase with its natural cofactor. Another model contains the reaction products, tetrahydrofolate and dTDP-Qui3NFo. In combination, the structures provide snapshots of the WlaRD active site before and after catalysis. On the basis of these structures, three amino acid residues were targeted for study: Asn 94, His 96, and Asp 132. Mutations of any of these residues resulted in a complete loss of enzymatic activity. Given the position of His 96 in the active site, it can be postulated that it functions as the active site base to remove a proton from the sugar amino group as it attacks the carbonyl carbon of the N-10 formyl group of the cofactor. Enzyme assays demonstrate that WlaRD is also capable of utilizing dTDP-3,6-dideoxy-3-amino-d-galactose (dTDP-Fuc3N) as a substrate, albeit at a much reduced catalytic efficiency. © 2013 American Chemical Society.
Keywords: Amino acid residues; Campylobacter jejuni; Carbonyl carbon; Catalytic efficiencies; Enzymatic activities; Gram-negative bacteria; Tetrahydrofolates; X-ray structure; Amino acids; Biochemistry; Carbon; Catalysis; Enzymes; Bacteria; amino acid; carbon; carbonyl derivative; folinic acid; galactose; glucose; histidine; n formyltransferase; O antigen; sugar; tetrahydrofolic acid; thymidine diphosphate; transferase; unclassified drug; article; biosynthesis; Campylobacter jejuni; catalysis; enzyme activity; enzyme assay; enzyme structure; mutation; nonhuman; outer membrane; priority journal; X ray

Thermochromic and photovoltaic properties of an alternating copolymer of dithieno[3,2-b:2′,3′-d]thiophene and thieno[3,4-c]pyrrole-4,6-dione - Li, Z.; Malenfant, P.; Tao, Y.; Ding, J. (Macromolecular Chemistry and Physics, 2013)
The synthesis of a new alternating conjugated polymer, PDTTTPD, based on electron-donating dithieno[3,2-b:2′,3′-d]thiophene (DTT) and electron-withdrawing thieno[3,4-c]pyrrole-4,6-dione (TPD) units is reported. This polymer shows strong thermochromic effect in chlorobenzene with a peak shift up to 170 nm. This phenomenon is studied with fluorescence spectroscopy and related to the steric hindrance along the polymer main chain. Polymer solar cells are fabricated from its blends with PC71BM, and shows modest power conversion efficiency up to 2.1%. The low efficiency is due to the low short-circuit current, which is also attributed to the steric effect. Based on these results, a general design rule for polymer photovoltaic material with controlled backbone conformation is proposed. A new alternating conjugated polymer, PDTTTPD, based on electron-rich dithieno[3,2-b:2′,3′-d] thiophene (DTT) and electron-deficient thieno[3,4-c]pyrrole-4,6-dione (TPD) building blocks is designed and synthesized. PDTTTPD shows strong thermochromic effect in chlorobenzene solution and modest PCE of 2.1% in organic solar cell devices due to the steric hindrance induced twisting of the conjugated main chain. A general design rule is then suggested to control the main chain conformation of polymer materials for photovoltaic applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Keywords: Alternating copolymer; Building blockes; Bulk heterojunction; Chlorobenzene solution; Electron-deficient; Electron-donating; Electron-rich; Electronwithdrawing; General designs; Main chains; Organic solar cell; Peak shift; Photovoltaic applications; Photovoltaic property; Polymer main chain; Polymer materials; Polymer photovoltaics; Polymer Solar Cells; Power conversion efficiencies; Steric effect; Steric hindrances; Thermo-chromic; Thermochromic effects; Chemical reactions; Conjugated polymers; Conversion efficiency; Electrons; Fluorescence spectroscopy; Heterojunctions; Solar cells; Thiophene; Polymer blends

Effect of metal ions on the reactions of the cumyloxyl radical with hydrogen atom donors. Fine control on hydrogen abstraction reactivity determined by Lewis acid-base interactions - Salamone, M.; Mangiacapra, L.; Dilabio, G.A.; Bietti, M. (Journal of the American Chemical Society, 2013)
A time-resolved kinetic study on the effect of metal ions (Mn+) on hydrogen abstraction reactions from C-H donor substrates by the cumyloxyl radical (CumO•) was carried out in acetonitrile. Metal salt addition was observed to increase the CumO• β-scission rate constant in the order Li+ > Mg2+ > Na+. These effects were explained in terms of the stabilization of the β-scission transition state determined by Lewis acid-base interactions between Mn+ and the radical. When hydrogen abstraction from 1,4-cyclohexadiene was studied in the presence of LiClO4 and Mg(ClO4)2, a slight increase in rate constant (k H) was observed indicating that interaction between Mn+ and CumO• can also influence, although to a limited extent, the hydrogen abstraction reactivity of alkoxyl radicals. With Lewis basic C-H donors such as THF and tertiary amines, a decrease in kH with increasing Lewis acidity of Mn+ was observed (kH(MeCN) > k H(Li+) > kH(Mg2+)). This behavior was explained in terms of the stronger Lewis acid-base interaction of M n+ with the substrate as compared to the radical. This interaction reduces the degree of overlap between the α-C-H σ* orbital and a heteroatom lone-pair, increasing the C-H BDE and destabilizing the carbon centered radical formed after abstraction. With tertiary amines, a >2-order of magnitude decrease in kH was measured after Mg(ClO 4)2 addition up to a 1.5:1 amine/Mg(ClO4) 2 ratio. At higher amine concentrations, very similar kH values were measured with and without Mg(ClO4)2. These results clearly show that with strong Lewis basic substrates variations in the nature and concentration of Mn+ can dramatically influence k H, allowing for a fine control of the substrate hydrogen atom donor ability, thus providing a convenient method for C-H deactivation. The implications and generality of these findings are discussed. © 2012 American Chemical Society.
Keywords: 1 ,4-cyclohexadienes; Alkoxyl radicals; Carbon-centered radicals; Donor ability; Donor substrates; Heteroatoms; Hydrogen abstraction; Hydrogen abstraction reaction; Hydrogen atoms; Lewis acid-base interaction; Lewis acidity; Lone pair; Metal salt; Tertiary amine; Time-resolved kinetic study; Transition state; Abstracting; Acetonitrile; Amines; Metal ions; Rate constants; Substrates; Hydrogen; 1,4 cyclohexadiene; acetonitrile; alkoxy radical; amine; cumyloxyl radical; hydrogen; inorganic salt; Lewis acid; Lewis base; lithium ion; lithium perchlorate; magnesium ion; magnesium perchlorate; metal ion; radical; sodium ion; unclassified drug; acid base balance; acidity; article; chemical reaction; chemical reaction kinetics; concentration response; hydrogen bond; molecular interaction; molecular stability; photolysis; Alcohols; Hydrogen; Ions; Lewis Acids; Lewis Bases; Lithium; Magnesium; Molecular Structure

Genome mining for new α-Amylase and Glucoamylase encoding sequences and high level expression of a Glucoamylase from Talaromyces stipitatus for potential raw starch hydrolysis - Xiao, Zhizhuang; Wu, Meiqun; Grosse, Stephan; Beauchemin, Manon; Lévesque, Michelle; Lau, Peter C. K. (Applied Biochemistry and Biotechnology, 2013)
Mining fungal genomes for glucoamylase and α-amylase encoding sequences led to the selection of 23 candidates, two of which (designated TSgam-2 and NFamy-2) were advanced to testing for cooked or raw starch hydrolysis. TSgam-2 is a 66-kDa glucoamylase recombinantly produced in Pichia pastoris and originally derived for Talaromyces stipitatus. When harvested in a 20-L bioreactor at high cell density (OD600 > 200), the secreted TSgam-2 enzyme activity from P. pastoris strain GS115 reached 800 U/mL. In a 6-L working volume of a 10-L fermentation, the TSgam-2 protein yield was estimated to be ∼8 g with a specific activity of 360 U/mg. In contrast, the highest activity of NFamy-2, a 70-kDa α-amylase originally derived from Neosartorya fischeri, and expressed in P. pastoris KM71 only reached 8 U/mL. Both proteins were purified and characterized in terms of pH and temperature optima, kinetic parameters, and thermostability. TSgam-2 was more thermostable than NFamy-2 with a respective half-life (t1/2) of >300 min at 55 °C and >200 min at 40 °C. The kinetic parameters for raw starch adsorption of TSgam-2 and NFamy-2 were also determined. A combination of NFamy-2 and TSgam-2 hydrolyzed cooked potato and triticale starch into glucose with yields, 71-87 %, that are competitive with commercially available α-amylases. In the hydrolysis of raw starch, the best hydrolysis condition was seen with a sequential addition of 40 U of a thermostable Bacillus globigii amylase (BgAmy)/g starch at 80 °C for 16 h, and 40 U TSgam-2/g starch at 45 °C for 24 h. The glucose released was 8.7 g/10 g of triticale starch and 7.9 g/10 g of potato starch, representing 95 and 86 % of starch degradation rate, respectively. © 2013 Her Majesty the Queen in Right of Canada.
Keywords: Fungal genomes; Amylase; Glucoamylase; Cold starch hydrolysis; Genome mining; Triticale; Potato starch; Pichia pastoris; Biocatalysts; Biorefinery

Bilayer molecular electronics: All-carbon electronic junctions containing molecular bilayers made with "click" chemistry - Sayed, S.Y.; Bayat, A.; Kondratenko, M.; Leroux, Y.; Hapiot, P.; McCreery, R.L. (Journal of the American Chemical Society, 2013)
Bilayer molecular junctions were fabricated by using the alkyne/azide "click" reaction on a carbon substrate, followed by deposition of a carbon top contact in a crossbar configuration. The click reaction on an alkyne layer formed by diazonium reduction permitted incorporation of a range of molecules into the resulting bilayer, including alkane, aromatic, and redox-active molecules, with high yield (>90%) and good reproducibility. Detailed characterization of the current-voltage behavior of bilayer molecular junctions indicated that charge transport is consistent with tunneling, but that the effective barrier does not strongly vary with molecular structure for the series of molecules studied. © 2013 American Chemical Society.
Keywords: Click reaction; Current voltage; Diazonium reduction; Electronic junctions; Molecular junction; Redox-active; Reproducibilities; Top contact; Molecules; Carbon; alkane derivative; alkyne derivative; carbon; diazonium compound; article; bilayer membrane; chemical structure; click chemistry; molecular electronics; molecule; oxidation reduction reaction; reduction

Stable all-nitrogen metallic salt at terapascal pressures - Sun, J.; Martinez-Canales, M.; Klug, D.D.; Pickard, C.J.; Needs, R.J. (Physical Review Letters, 2013)
The phase diagram and equation of state of dense nitrogen are of interest in understanding the fundamental physics and chemistry under extreme conditions, including planetary processes, and in discovering new materials. We predict several stable phases of nitrogen at multi-TPa pressures, including a P4/nbm structure consisting of partially charged N2δ+ pairs and N5δ- tetrahedra, which is stable in the range 2.5-6.8 TPa. This is followed by a modulated layered structure between 6.8 and 12.6 TPa, which also exhibits a significant charge transfer. The P4/nbm metallic nitrogen salt and the modulated structure are stable at high pressures and temperatures, and they exhibit strongly ionic features and charge density distortions, which is unexpected in an element under such extreme conditions and could represent a new class of nitrogen materials. The P-T phase diagram of nitrogen at TPa pressures is investigated using quasiharmonic phonon calculations and ab initio molecular dynamics simulations. © 2013 American Physical Society.
Keywords: Ab initio molecular dynamics simulation; Equation of state; Extreme conditions; Fundamental physics; Layered Structures; Modulated structures; P-T phase diagram; Phonon calculation; Calculations; Equations of state; High pressure engineering; Molecular dynamics; Phase diagrams; Nitrogen

Finite element-based modeling of machining-induced residual stresses in Ti-6Al-4V under finish turning conditions - Abboud, E.; Shi, B.; Attia, H.; Thomson, V.; Mebrahtu, Y. (Procedia CIRP, 2013)
Residual stresses (RS) imparted during the finishing stages of machining constitute an essential measure of surface integrity and an acceptance criterion for the safety of critical aerospace parts. To build a predictive tool for machining-induced residual stresses in titanium alloy Ti-6Al-4V, a finite element-based model of orthogonal cutting is developed using DEFORM-2D. A full factorial orthogonal cutting experiment is conducted using sharp tools to investigate the effect of feed rate (f) and cutting speed (v) on residual stresses under finish-turning conditions. For every cutting condition, machining forces are measured using a piezoelectric dynamometer, surface temperatures in the vicinity of the cutting zone are captured with an infra-red camera, and surface residual stresses in the cutting direction are measured by X-ray diffraction (XRD). Experimental results for forces, temperatures and RS are used to validate the finite element model. Once a high confidence level in finite element predictions is obtained, a numerical investigation of the effects of cutting tool edge radius (r) and cutting speed on RS is carried out. Within the investigated range of parameters, residual stresses are found to be compressive in nature. It is observed that residual stresses become more compressive with increasing feed rate and less compressive with increasing edge radius or cutting speed. Copyright © 2013 Elsevier B.V.
Keywords: Cutting speed; Edge radius; FE modeling; Feed-rates; Finite-element predictions; Numerical investigations; Surface residual stress; Surface temperatures; Atmospheric temperature; Cutting; Cutting tools; Finite element method; Machining centers; Titanium; Titanium alloys; Turning; X ray diffraction; Residual stresses

Translational biomarker discovery in clinical metabolomics: An introductory tutorial - Xia, J.; Broadhurst, D.I.; Wilson, M.; Wishart, D.S. (Metabolomics, 2013)
Metabolomics is increasingly being applied towards the identification of biomarkers for disease diagnosis, prognosis and risk prediction. Unfortunately among the many published metabolomic studies focusing on biomarker discovery, there is very little consistency and relatively little rigor in how researchers select, assess or report their candidate biomarkers. In particular, few studies report any measure of sensitivity, specificity, or provide receiver operator characteristic (ROC) curves with associated confidence intervals. Even fewer studies explicitly describe or release the biomarker model used to generate their ROC curves. This is surprising given that for biomarker studies in most other biomedical fields, ROC curve analysis is generally considered the standard method for performance assessment. Because the ultimate goal of biomarker discovery is the translation of those biomarkers to clinical practice, it is clear that the metabolomics community needs to start "speaking the same language" in terms of biomarker analysis and reporting-especially if it wants to see metabolite markers being routinely used in the clinic. In this tutorial, we will first introduce the concept of ROC curves and describe their use in single biomarker analysis for clinical chemistry. This includes the construction of ROC curves, understanding the meaning of area under ROC curves (AUC) and partial AUC, as well as the calculation of confidence intervals. The second part of the tutorial focuses on biomarker analyses within the context of metabolomics. This section describes different statistical and machine learning strategies that can be used to create multi-metabolite biomarker models and explains how these models can be assessed using ROC curves. In the third part of the tutorial we discuss common issues and potential pitfalls associated with different analysis methods and provide readers with a list of nine recommendations for biomarker analysis and reporting. To help readers test, visualize and explore the concepts presented in this tutorial, we also introduce a web-based tool called ROCCET (ROC Curve Explorer & Tester, http://www. roccet. ca). ROCCET was originally developed as a teaching aid but it can also serve as a training and testing resource to assist metabolomics researchers build biomarker models and conduct a range of common ROC curve analyses for biomarker studies. © 2012 The Author(s).
Keywords: acylcarnitine; amino acid; biological marker; prostate specific antigen; analytic method; analytical parameters; article; bioinformatics; clinical chemistry; clinical practice; computer program; confidence interval; data processing; diagnostic test; discriminant analysis; gold standard; heart disease; human; inborn error of metabolism; intermethod comparison; machine learning; malignant neoplastic disease; mathematical computing; metabolite; metabolomics; neurologic disease; newborn screening; partial least squares regression; predictive value; principal component analysis; process development; process model; process optimization; prognosis; protein analysis; protein blood level; protein function; protein processing; protein secretion; receiver operating characteristic; reliability; risk assessment; sample size; screening test; sensitivity and specificity; standard; statistical analysis; validation process

Immunogenic and protective properties of GP5 and M structural proteins of porcine reproductive and respiratory syndrome virus expressed from replicating but nondisseminating adenovectors - Roques, E.; Girard, A.; St-Louis, M.-C.; Massie, B.; Gagnon, C.A.; Lessard, M.; Archambault, D. (Veterinary Research, 2013)
Porcine reproductive and respiratory syndrome virus (PRRSV) is responsible for significant economic losses in the porcine industry. Currently available commercial vaccines do not allow optimal and safe protection. In this study, replicating but nondisseminating adenovectors (rAdV) were used for the first time in pigs for vaccinal purposes. They were expressing the PRRSV matrix M protein in fusion with either the envelope GP5 wild-type protein (M-GP5) which carries the major neutralizing antibody (NAb)-inducing epitope or a mutant form of GP5 (M-GP5m) developed to theoretically increase the NAb immune response. Three groups of fourteen piglets were immunized both intramuscularly and intranasally at 3-week intervals with rAdV expressing the green fluorescent protein (GFP, used as a negative control), M-GP5 or M-GP5m. Two additional groups of pigs were primed with M-GP5m-expressing rAdV followed by a boost with bacterially-expressed recombinant wild-type GP5 or were immunized twice with a PRRSV inactivated commercial vaccine. The results show that the rAdV expressing the fusion proteins of interest induced systemic and mucosal PRRSV GP5-specific antibody response as determined in an ELISA. Moreover the prime with M-GP5m-expressing rAdV and boost with recombinant GP5 showed the highest antibody response against GP5. Following PRRSV experimental challenge, pigs immunized twice with rAdV expressing either M-GP5 or M-GP5m developed partial protection as shown by a decrease in viremia overtime. The lowest viremia levels and/or percentages of macroscopic lung lesions were obtained in pigs immunized twice with either the rAdV expressing M-GP5m or the PRRSV inactivated commercial vaccine. © 2013 Roques et al.; licensee BioMed Central Ltd.
Keywords: Arterivirus; Porcine respiratory and reproductive syndrome virus; Suidae; Sus

Recent star formation in the Lupus clouds as seen by Herschel - Rygl, K.L.J.; Benedettini, M.; Schisano, E.; Elia, D.; Molinari, S.; Pezzuto, S.; André, Ph.; Bernard, J.P.; White, G.J.; Polychroni, D.; Bontemps, S.; Cox, N.L.J.; et al. (Astronomy and Astrophysics, 2013)
We present a study of the star formation histories of the Lupus I, III, and IV clouds using the Herschel 70-500μm maps obtained by the Herschel Gould Belt Survey Key Project. By combining the new Herschel data with the existing Spitzer catalog we obtained an unprecedented census of prestellar sources and young stellar objects in the Lupus clouds, which allowed us to study the overall star formation rate (SFR) and efficiency (SFE). The high SFE of Lupus III, its decreasing SFR, and its large number of pre-main sequence stars with respect to proto-and prestellar sources, suggest that Lupus III is the most evolved cloud, and after having experienced a major star formation event in the past, is now approaching the end of its current star-forming cycle. Lupus I is currently undergoing a large star formation event, apparent by the increasing SFR, the large number of prestellar objects with respect to more evolved objects, and the high percentage of material at high extinction (e.g., above AVA ≈ A 8A mag). Also Lupus IV has an increasing SFR; however, the relative number of prestellar sources is much lower, suggesting that its star formation has not yet reached its peak. © 2012 ESO.
Keywords: Gould belt; HERSCHEL; Infrared: ISM; ISM: individual objects; Pre-main sequences; Spitzer; Star formation rates; Star formations; Stars: formation; Stars: protostars; Young stellar objects; Surveys; Stars

Altered network communication following a neuroprotective drug treatment - Vincent, K.; Tauskela, J.S.; Mealing, G.A.; Thivierge, J.-P. (PLoS ONE, 2013)
Preconditioning is defined as a range of stimuli that allow cells to withstand subsequent anaerobic and other deleterious conditions. While cell protection under preconditioning is well established, this paper investigates the influence of neuroprotective preconditioning drugs, 4-aminopyridine and bicuculline (4-AP/bic), on synaptic communication across a broad network of in vitro rat cortical neurons. Using a permutation test, we evaluated cross-correlations of extracellular spiking activity across all pairs of recording electrodes on a 64-channel multielectrode array. The resulting functional connectivity maps were analyzed in terms of their graph-theoretic properties. A small-world effect was found, characterized by a functional network with high clustering coefficient and short average path length. Twenty-four hours after exposure to 4-AP/bic, small-world properties were comparable to control cultures that were not treated with the drug. Four hours following drug washout, however, the density of functional connections increased, while path length decreased and clustering coefficient increased. These alterations in functional connectivity were maintained at four days post-washout, suggesting that 4-AP/bic preconditioning leads to long-term effects on functional networks of cortical neurons. Because of their influence on communication efficiency in neuronal networks, alterations in small-world properties hold implications for information processing in brain systems. The observed relationship between density, path length, and clustering coefficient is captured by a phenomenological model where connections are added randomly within a spatially-embedded network. Taken together, results provide information regarding functional consequences of drug therapies that are overlooked in traditional viability studies and present the first investigation of functional networks under neuroprotective preconditioning. © 2013 Vincent et al.
Keywords: neuroprotective agent; animal cell; animal tissue; article; brain cell; brain function; brain mapping; cell density; controlled study; drug mechanism; extracellular space; in vitro study; ischemic preconditioning; nerve cell network; nonhuman; rat; reaction time; synaptic transmission; theoretical study; 4-Aminopyridine; Animals; Bicuculline; Brain; Brain Mapping; Electroencephalography; Nerve Net; Neural Pathways; Neurons; Neuroprotective Agents; Rats; Rattus

Solid-state transformation of iron-rich intermetallic phases in Al-Cu 206 cast alloys during solution heat treatment - Liu, K.; Cao, X.; Chen, X.-G. (Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 2013)
The solid-state transformation of the iron-rich intermetallic phases in Al-Cu 206 cast alloys during the solution heat treatment was studied by using Scanning Electron Microscope (SEM), Electron Back Scattered Diffraction (EBSD), Differential Scanning Calorimeter (DSC), and Transmission Electron Microscope (TEM). At a normal solution treatment temperature of 793 K (520 C), no visible variation is observed for the β-Fe phase solidified from the Al alloy melt. With increasing soaking time, however, the Chinese script α-Fe becomes unstable and progressively transforms into platelet β-Fe, termed as solid-state-transformed (STed) β-Fe to distinguish it from the β-Fe directly solidified from the Al alloy melt. The STed β-Fe preferentially nucleates on the α-Fe and then grows from the α-Fe/Al interface into α-Fe and/or Al matrix with a much higher growth rate in the α-Fe. The incomplete solid-state transformation from α-Fe into STed β-Fe leads to the fragmentation of the α-Fe. The formation of the STed β-Fe with increasing size and volume fraction after longer soaking time can deteriorate the tensile properties. © 2013 The Minerals, Metals & Materials Society and ASM International.
Keywords: Chinese script; D. transmission electron microscopes (TEM); Differential scanning calorimeters; Electron back-scattered diffraction; Intermetallic phasis; Normal solutions; Solid state transformations; Solution heat treatment; Alloys; Aluminum; Cast iron; Copper alloys; Differential scanning calorimetry; Heat treatment; Scanning electron microscopy; Transmission electron microscopy; Iron alloys

Intrinsic role of FoxO3a in the development of CD8+ T Cell memory - Tzelepis, F.; Joseph, J.; Haddad, E.K.; MacLean, S.; Dudani, R.; Agenes, F.; Peng, S.L.; Sekaly, R.-P.; Sad, S. (Journal of Immunology, 2013)
CD8+ T cells undergo rapid expansion during infection with intracellular pathogens, which is followed by swift and massive culling of primed CD8+ T cells. The mechanisms that govern the massive contraction and maintenance of primed CD8+ T cells are not clear. We show in this study that the transcription factor, FoxO3a, does not influence Ag presentation and the consequent expansion of CD8+ T cell response during Listeria monocytogenes infection, but plays a key role in the maintenance of memory CD8+ T cells. The effector function of primed CD8+ T cells as revealed by cytokine secretion and CD107a degranulation was not influenced by inactivation of FoxO3a. Interestingly, FoxO3a-deficient CD8+ T cells displayed reduced expression of proapoptotic molecules BIM and PUMA during the various phases of response, and underwent reduced apoptosis in comparison with wild-type cells. A higher number of memory precursor effector cells and memory subsets was detectable in FoxO3a-deficient mice compared with wild-type mice. Furthermore, FoxO3a-deficient memory CD8+ T cells upon transfer into normal or RAG1-deficient mice displayed enhanced survival. These results suggest that FoxO3a acts in a cell-intrinsic manner to regulate the survival of primed CD8+ T cells. Copyright © 2013 by The American Association of Immunologists, Inc.
Keywords: actin; BIM protein; cytokine; lysosome associated membrane protein 1; protein Bid; PUMA protein; RAG1 protein; transcription factor FKHRL1; animal cell; animal experiment; animal model; antigen presentation; apoptosis; article; CD8+ T lymphocyte; cell expansion; cell survival; controlled study; cytokine release; degranulation; effector cell; female; listeriosis; lymphocyte function; memory T lymphocyte; mouse; nonhuman; pre T lymphocyte; priority journal; protein analysis; protein deficiency; protein expression; protein function; wild type; Animals; Antigen Presentation; Antigens, Bacterial; Apoptosis; Apoptosis Regulatory Proteins; CD8-Positive T-Lymphocytes; Cytokines; Cytotoxicity, Immunologic; Female; Forkhead Transcription Factors; Homeodomain Proteins; Immunologic Memory; L-Selectin; Listeria monocytogenes; Listeriosis; Lymphocyte Activation; Lymphocyte Subsets; Lymphokines; Lysosome-Associated Membrane Glycoproteins; Membrane Proteins; Mice; Mice, Inbred C57BL; Ovalbumin; Proto-Oncogene Proteins; Receptors, Interleukin-7; Tumor Suppressor Proteins

Stiction-free fabrication of lithographic nanostructures on resist-supported nanomechanical resonators - Diao, Z.; Losby, J.E.; Burgess, J.A.J.; Sauer, V.T.K.; Hiebert, W.K.; Freeman, M.R. (Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 2013)
The authors report a highly flexible process for nanostructure lithography to incorporate specific functions in micro- and nanomechanical devices. The unique step involves electron beam patterning on top of released, resist-supported, surface micromachined structures, hence avoiding hydrofluoric acid etching of sensitive materials during the device release. The authors demonstrate the process by creating large arrays of nanomechanical torque magnetometers on silicon-on-insulator substrates. The fabricated devices show a thermomechanical noise-limited magnetic moment sensitivity in the range of 5 × 106 μB at room temperature and can be utilized to study both magnetostatics and dynamics in nanomagnets across a wide temperature range. The fabrication process can be generalized for the deposition and patterning of a wide range of materials on micro-/nanomechanical resonators. © 2013 Crown.
Keywords: Electron beam patterning; Fabrication process; Hydrofluoric acid etching; Nanomechanical device; Nanomechanical resonators; Silicon-on-insulator substrates; Surface micromachined structure; Wide temperature ranges; Hydrofluoric acid; Magnetic moments; Magnetostatics; Nanostructures; Resonators; Thermomechanical treatment; Fabrication

Clathrin- and arp2/3-independent endocytosis in the fungal pathogen Candida albicans - Epp, E.; Nazarova, E.; Regan, H.; Douglas, L.M.; Konopka, J.B.; Vogel, J.; Whiteway, M. (mBio, 2013)
Clathrin-mediated endocytosis (CME) is conserved among eukaryotes and has been extensively analyzed at a molecular level. Here, we present an analysis of CME in the human fungal pathogen Candida albicans that shows the same modular structure as those in other fungi and mammalian cells. Intriguingly, C. albicans is perfectly viable in the absence of Arp2/3, an essential component of CME in other systems. In C. albicans, Arp2/3 function remains essential for CME as all 15 proteins tested that participate in CME, including clathrin, lose their characteristic dynamics observed in wild-type (WT) cells. However, since arp2/3 cells are still able to endocytose lipids and fluid-phase markers, but not the Ste2 and Mup1 plasma membrane proteins, there must be an alternate clathrin-independent pathway we term Arp2/3-independent endocytosis (AIE). Characterization of AIE shows that endocytosis in arp2 mutants relies on actin cables and other Arp2/3-independent actin structures, as inhibition of actin functions prevented cargo uptake in arp2/3 mutants. Transmission electron microscopy (TEM) showed that arp2/3 mutants still formed invaginating tubules, cell structures whose proper functions are believed to heavily rely on Arp2/3. Finally, Prk1 and Sjl2, two proteins involved in patch disassembly during CME, were not correctly localized to sites of endocytosis in arp2 mutants, implying a role of Arp2/3 in CME patch disassembly. Overall, C. albicans contains an alternative endocytic pathway (AIE) that relies on actin cable function to permit clathrin-independent endocytosis (CIE) and provides a system to further explore alternate endocytic routes that likely exist in fungal species. © 2013 Epp et al.

Synthesis, characterization and evaluation of unsupported porous NiS 2 sub-micrometer spheres as a potential hydrodesulfurization catalyst - Mondal, D.; Villemure, G.; Li, G.; Song, C.; Zhang, J.; Hui, R.; Chen, J.; Fairbridge, C. (Applied Catalysis A: General, 2013)
Nanostructured NiS2 has attracted interest due to its wide applications and special properties. Synthesis of a pure phase NiS2 in a single step has been a challenge. In this work, a new method for direct synthesis of uniform NiS2/SiO2 sub microspheres has been developed by ultrasonic spray pyrolysis. Colloidal silica was used as a sacrificial template to create the porous structure. After silica removal, hollow, porous NiS2 nano spheres were obtained. The product was characterized by using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction (XRD), transmission electron microscopy and N2 adsorption/desorption isotherm. XRD confirmed the formation of single phase pyrite NiS2. It was found that the porous spherical NiS2 has a surface area of ca. 300 m2 g-1. The HDS catalytic activity of NiS2 was evaluated using a model compound, dibenzothiophene (DBT). It showed a first order reaction rate constant of 1.51 × 10-4 s-1 g cata-1 at 320 °C for HDS of DBT, which is significantly promising for further exploration. © 2012 Published by Elsevier B.V.
Keywords: Adsorption/desorption; Colloidal silica; Dibenzothiophenes; Direct synthesis; Energy dispersive X ray spectroscopy; First-order reaction rate constant; HDS of DBT; Hydrodesulfurization catalysts; Model compound; Nano-structured; Porous structures; Silica removal; Single phase; Single-step; Special properties; Submicrometers; Surface area; Ultrasonic spray pyrolysis; XRD; Rate constants; Scanning electron microscopy; Silica; Spray pyrolysis; Transmission electron microscopy; X ray diffraction; X ray spectroscopy; Hydrodesulfurization

Microstructure and hardness of fiber laser deposited Inconel 718 using filler wire - Zhang, Y.N.; Cao, X.; Wanjara, P. (International Journal of Advanced Manufacturing Technology, 2013)
A continuous wave 5 kW fiber laser welding system was used to deposit INCONEL® alloy 718 (IN718) layers in conduction mode by applying filler wire with a composition similar to the parent metal, which was extracted directly from a scrapped, service-exposed IN718 aerospace component. The quality of the deposits was characterized in both the as-deposited and fully heat-treated conditions in terms of the macrostructure, defects, microstructure, and hardness. Integral deposits with no visible porosity were obtained using the fiber laser deposition technique. In the as-deposited clad zone, weld metal liquation cracking led to the presence of minor microcracks in the lower layer beads near the layer interface. The crack healing behavior observed after post-clad heat treatment of the IN718 deposits supports the marked potential of using the laser deposition technique by filler wire addition to manufacture and repair/remanufacture superalloy components for aerospace applications. © 2013 Her Majesty the Queen in Right of Canada as represented by: National Research Council Canada.

Spring wheat yield in the semiarid Canadian prairies: Effects of precipitation timing and soil texture over recent 30 years - He, Y.; Wei, Y.; DePauw, R.; Qian, B.; Lemke, R.; Singh, A.; Cuthbert, R.; McConkey, B.; Wang, H. (Field Crops Research, 2013)
The large year-to-year and site-to-site variation in wheat production on rain-fed semiarid areas of the Canadian prairies is mainly due to the timing and amount of precipitation and soil water holding capacity. Here, we identify the critical periods of growing season precipitation on wheat yield and then utilize this information to analyze which type of soil texture had higher drought resistance and higher grain yield when precipitation was more than sufficient. Thirty years (1982-2011) of grain yield data on two sites located in the same rain-fed area with different soil texture types were used in our analysis. To seek the critical periods of precipitation on yield, correlation over the whole growing season between precipitation and yield was first analyzed. By doing this, we calculated not only when the precipitation occurs that was most related to yield but also the duration of this period. To further understand these cause-and-effect interrelationships, a modern version of path analysis - Structural Equation Modeling (SEM) was used. The result of SEM was satisfactory since 67% of yield variation can be explained by only 3 exogenous variables (early and late precipitation and fertilizer N) and 2 intermediate variables (thousand kernel weight and kernel nitrogen concentration). Results showed that early precipitation (from seeding to anthesis) was most critical for high grain yield in our study area. Clay soil has a higher drought tolerance efficiency and lower drought susceptibility index. Grain yield was higher on the clay soil than on the silt loam soil in most dry and wet years. We conclude that early precipitation had a deterministic effect on grain yield. The clay soil has a more stable yield under current fertilizer rates and the climate conditions in our study area. These results may lead to a better understanding of the crop-environmental interactions enabling breeders to analyze their experimental trials with regard to the broad environments that they target. © 2013.
Keywords: clay soil; crop production; crop yield; drought resistance; growing season; prairie; precipitation (climatology); semiarid region; soil texture; soil water; wheat; Canada; Triticum aestivum

Derivation and new analysis of a hydrodynamic model of speed skate ice friction - Lozowski, E.P.; Szilder, K. (International Journal of Offshore and Polar Engineering, 2013)
This paper presents the mathematical derivation of a new model of speed skate ice friction. The model acronym is FAST, which stands for friction algorithm using speed skate thermohydrodynamics. Mutatis mutandis, it is applicable to other ice friction problems in the hydrodynamic friction regime. This paper updates and corrects an earlier publication of the model that omitted the full derivation of the lubrication equation (Penny et al., 2007). It also updates the ice hardness equation based on new measurements, and it presents a more thorough exploration of the model results and its sensitivity to the variation of physical variables. © by The International Society of Offshore and Polar Engineers.
Keywords: Hydrodynamic friction; Hydrodynamic model; Lubrication equation; Mathematical derivation; Mutatis-mutandis; Physical variables; Theory; Thermohydrodynamics; Fluid dynamics; Friction; Ice; Models; Physics; Sensitivity analysis; Tribology; Recreational facilities; friction; hydrodynamics; ice; measurement method; numerical model; sensitivity analysis; theoretical study; thermodynamics

Formation and phase selection of iron-rich intermetallics in Al-4.6Cu-0.5Fe cast alloys - Liu, K.; Cao, X.; Chen, X.-G. (Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 2013)
The solidification structures of Al-Cu 206 cast alloys at a high iron level of 0.5 pct were systematically studied by means of differential scanning calorimetry, electron backscattered diffraction, and transmission electron microscopy. The full solidification sequences of the 206 cast alloys at 0.5 pct Fe were established. The influences of both alloy composition (i.e., Si and Mn contents) and cooling rate on the formation and phase selection of the iron-rich intermetallics have been systematically explored. At a cooling rate of 12 K/min, it was found that one of the three iron-rich phases, i.e., Chinese script Alm(FeMn) and α-Fe, or platelet Al3(FeMn), may precipitate as the dominant iron-rich intermetallic, depending on Si and Mn contents. However, the dominant Chinese script iron-rich intermetallics, Al m(FeMn) and/or α-Fe, can be fully obtained for the 206 Al-Cu cast alloys at 0.5 pct Fe above a threshold cooling rate that can easily be obtained in normal industrial casting conditions, indicating that there is a significant potential of designing and developing new 206 Al-Cu cast alloys with a high tolerant iron content. © 2012 Reprinted with permission of Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources.
Keywords: Alloy compositions; Chinese script; Cooling rates; Electron back-scattered diffraction; Industrial casting; Phase selection; Solidification sequence; Solidification structure; Aluminum; Cast iron; Cerium alloys; Cooling; Copper alloys; Differential scanning calorimetry; Iron; Iron alloys; Manganese; Silicon; Solidification; Transmission electron microscopy; Intermetallics

Perturbing the metabolic dynamics of myo-inositol in developing Brassica napus seeds through in vivo methylation impacts its utilization as phytate precursor and affects downstream metabolic pathways - Dong, J.; Yan, W.; Bock, C.; Nokhrina, K.; Keller, W.; Georges, F. (BMC Plant Biology, 2013)
Background: myo-Inositol (Ins) metabolism during early stages of seed development plays an important role in determining the distributional relationships of some seed storage components such as the antinutritional factors, sucrose galactosides (also known as raffinose oligosaccharides) and phytic acid (PhA) (myo-inositol 1,2,3,4,5,6-hexakisphosphate). The former is a group of oligosaccharides, which plays a role in desiccation at seed maturation. They are not easily digested by monogastric animals, hence their flatulence-causing properties. Phytic acid is highly negatively charged, which chelates positive ions of essential minerals and decreases their bioavailability. It is also a major cause of phosphate-related water pollution. Our aim was to investigate the influence of competitive diversion of Ins as common substrate on the biosynthesis of phytate and sucrose galactosides. Results: We have studied the initial metabolic patterns of Ins in developing seeds of Brassica napus and determined that early stages of seed development are marked by rapid deployment of Ins into a variety of pathways, dominated by interconversion of polar (Ins phosphates) and non-polar (phospholipids) species. In a time course experiment at early stages of seed development, we show Ins to be a highly significant constituent of the endosperm and seed coat, but with no phytate biosynthesis occurring in either tissue. Phytate accumulation appears to be confined mainly within the embryo throughout seed development and maturation. In our approach, the gene for myo-inositol methyltransferase (IMT), isolated from Mesembryanthemum crystallinum (ice plant), was transferred to B. napus under the control of the seed-specific promoters, napin and phaseolin. Introduction of this new metabolic step during seed development prompted Ins conversion to the corresponding monomethyl ether, ononitol, and affected phytate accumulation. We were able to produce homozygous transgenic lines with 19% - 35% average phytate reduction. Additionally, changes in the raffinose content and related sugars occurred along with enhanced sucrose levels. Germination rates, viability and other seed parameters were unaffected by the IMT transgene over-expression. Conclusions: Competitive methylation of Ins during seed development reduces seed antinutritional components and enhances its nutritional characteristics while maintaining adequate phosphate reserves. Such approach should potentially raise the canola market value and likely, that of other crops. © 2013 Dong et al.; licensee BioMed Central Ltd.
Keywords: Animalia; Brassica napus; Brassica napus var. napus; Mesembryanthemum; Mesembryanthemum crystallinum; inositol; phytic acid; article; germination; growth, development and aging; metabolism; methylation; plant seed; rapeseed; Brassica napus; Germination; Inositol; Metabolic Networks and Pathways; Methylation; Phytic Acid; Seeds

Towards a physical picture of star formation quenching: The photometric properties of recently quenched galaxies in the sloan digital sky survey - Mendel, T.J.; Simard, L.; Ellison, S.L.; Patton, D.R. (Monthly Notices of the Royal Astronomical Society, 2013)
We select a sample of young passive galaxies from the Sloan Digital Sky Survey data release 7 in order to study the processes that quench star formation in the local universe. Quenched galaxies are identified based on the contribution of A-type stars to their observed (central) spectra and relative lack of ongoing star formation; we find that such systems account for roughly 2.5 per cent of all galaxies with log(M/M⊙)≥ = 9.5, and have a space density of ~2.2×10-4 Mpc-3.We show that quenched galaxies span a range of morphologies, but visual classifications suggest that they are predominantly early-type systems. Their visual early-type classification is supported by quantitative structural measurements (śersic indices) that show a notable lack of disc-dominated galaxies, suggesting that any morphological transformation associated with galaxies' transition from star forming to passive - e.g. the formation of a stellar bulge - occurs contemporaneously with the decline of their star formation activity. We show that there is no clear excess of optical active galactic nuclei (AGN) in quenched galaxies, suggesting that: (i) AGN feedback is not associated with the majority of quenched systems or (ii) that the observability of quenched galaxies is such that the quenching phase in general outlives any associated nuclear activity. Comparison with classical post-starburst galaxies shows that both populations show similar signatures of bulge growth, and we suggest that the defining characteristic of post-starburst galaxies is the efficiency of their bulge growth rather than a particular formation mechanism. © 2011 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Effects of heat-treatment and pyridine addition on the catalytic activity of carbon-supported cobalt-phthalocyanine for oxygen reduction reaction in alkaline electrolyte - Dai, X.; Qiao, J.; Zhou, X.; Shi, J.; Xu, P.; Zhang, L.; Zhang, J. (International Journal of Electrochemical Science, 2013)
Carbon-supported non-precious metal (cobalt) catalysts, namely Py-CoPc/C, where Py is the pyridine and Pc is the phthalocyanine, are synthesized for oxygen reduction reaction (ORR) using combined solvent-impregnation and high-temperature treatment process. The heat-treatment effect on the catalysts' activity toward ORR is examined using catalysts obtained at 600, 700, 800, and 900°C, respectively. The effect of pyridine addition on the ORR activity is also studied. It is found that the formed Py-CoPc/C catalysts all show the higher ORR activities than that of CoPc/C catalyst, and the catalyst obtained at 700°C treatment gives the best activity for the ORR in 0.1M KOH solution, which are tested using both CV and RDE techniques. XRD, TEM as well as XPS are employed to study the crystal structures, morphologies and surface structure changes of the synthesized Py-CoPc/C catalysts. Both XRD and TEM analysis indicate the formation of different amounts of Co-NX-C active site at different heat-treatment temperatures, which is well correlated with the catalysts' ORR activities. XPS results suggest that the pyridinic-N and graphitic-N groups are both responsible for the enhanced ORR activity, and the catalyst formed at 700°C treatment shows the most amount of these two groups, leading to the most active ORR catalyst. © 2013 by ESG.

Characteristics of H13 tool steel coatings by pulsed Nd:YAG laser cladding - Wang, S.; Chen, J.; Xue, L. (TMS Annual Meeting, 2013)
AISI H13 hot-work tool steel has a wide application for mold/die of die casting, hot forging, hot extrusion, hot stamping and plastic injection molding, due to its high toughness, high hot hardness and high thermal fatigue resistance. Laser cladding, a material additive technology, can be used to apply various functional coatings and to repair/reconfigure tool/die. H13 tool steel was successfully laser-clad on carbon steel substrates at room temperature. The microstructure of as-clad coating showed a refined dendritic structure due to fast cooling and rapid solidification. X-ray diffraction (XRD) phase identification revealed that the coating consisted of a majority of martensite phase plus certain amount of retained austenite phase (∼ 20 vol%). Tensile residual stresses were measured in the as-clad H13 coating. The average value of Vickers hardness in the as-clad coating is about 575 Hv0.05. Wear resistance evaluation using pin-on-disc sliding wear testing showed that the wear resistance of as-clad H13 steel coating was similar to or slightly better than that of hardened wrought H13 steel (HRC 54) plate under the wear test condition used in this study, but the wear mechanisms are significantly different.
Keywords: Carbon steel substrates; Dendritic structures; H13 tool steel; Hot-work tool steel; Phase identification; Plastic injection molding; Pulsed Nd:YAG laser; Tensile residual stress; Carbon steel; Coatings; Die casting; Exhibitions; Laser cladding; Protective coatings; Rapid solidification; Steel testing; Tool steel; Tribology; Wear resistance; X ray diffraction; Neodymium lasers

Phased microphone array measurements of a bombardier aircraft scaled model - Syms, G.F.; Mamou, M. (19th AIAA/CEAS Aeroacoustics Conference, 2013)
Aerodynamic testing of high fidelity models is a standard practice for aircraft manufacturers. With the development of phased microphone array technology, aeroacoustics can become an integral part of the design process of an airplane. In 2012, the National Research Council Canada and Bombardier Aerospace carried out a collaborative research program focusing on measuring the sound generated by a high-fidelity aerodynamic wind tunnel model. The noise of various configurations was measured at combinations of three wind speeds and three microphone array polar orientations above the model. Several calibration reference noise waveforms were explored to determine the most effective in a highly reverberant hard-walled test section. The calibration data analysis showed that meaningful beamform maps above 30kHz could be generated when a pulsed sine wave was applied as the reference noise signal in the calibration process. For the model configurations tested, slat noise dominated the sound maps processed using either conventional beamforming or CLEAN-PSF. The wing flap edge noise as well as the contributions from the main gear were also discernible. For each configuration, one data point was taken while the microphone array was rotating instead of stationary. The computationally intense post-processing procedure for these data provided a detailed map of the sources due to reduced spatial aliasing. The sound levels measured with the rotating array were at a slightly lower magnitude owing to the averaging of the source over its full directivity pattern. Future work includes implementing a calibration procedure for the rotating array and improving the signal-to-noise ratio of the signals so that shorter microphone time histories can be used to extract directivity information from the datasets of the rotating array.
Keywords: Aerodynamic wind tunnel model; Aircraft manufacturers; Bombardier aerospaces; Calibration procedure; Collaborative research; Conventional beamforming; National Research Council; Post-processing procedure; Aeroacoustics; Aerodynamics; Aircraft models; Calibration; Microphones; Acoustic noise

Hyperfine-structure splitting of the 716 nm R(90)3-10 molecular iodine transition - Huet, N.; Krins, S.; Dubé, P.; Bastin, T. (Journal of the Optical Society of America B: Optical Physics, 2013)
We report on the hyperfine-structure splitting of the 716 nm R(90)3-10 molecular iodine transition.We show that this particular iodine line provides a very useful frequency reference in the context of a laser cooling experiment of iron atoms, an atomic species that has so far never been laser cooled and trapped to our knowledge. We provide experimental values for the hyperfine constants ΔeQq and ΔC of the investigated iodine transition. Dispersive signals of this transition are also presented and used to lock the frequency of a Ti:sapphire laser. The reported stabilization performance is fully compatible with the requirements of a laser cooling experiment of iron atoms. © 2013 Optical Society of America.
Keywords: Atomic species; Dispersive signals; Experimental values; Frequency reference; Fully compatible; Hyperfine constants; Molecular iodine; Ti: Sapphire laser; Atoms; Experiments; Laser cooling; Iodine

Investigation of a postprocessing method to tailor the mechanical properties of carbon nanotube/polyamide fibers - Palardy, G.; Trudel-Boucher, D.; Hubert, P. (Journal of Applied Polymer Science, 2013)
The incorporation of carbon nanotubes to thermoplastic fibers can potentially improve mechanical, thermal and electrical properties. In this article, a methodology to tailor the mechanical properties of carbon nanotube/nylon fibers is presented. Multiwalled nanotubes (MWNT) were combined to polyamide 12 through melt compounding and twin-screw extrusion. Pellets containing between 0 and 5.0 wt % MWNT were extruded and subsequently melt spun with a capillary rheometer to produce filaments. To further promote the alignment of the polymer chains and MWNTs, postdrawing parameters were systematically investigated: temperature, drawing speed and elongation. The best improvements in terms of elastic modulus and yield strength were measured at 140°C and 500% elongation, whereas drawing speed was shown to have a negligible effect. It was confirmed through electron microscopy and X-ray diffraction that these enhancements were mainly induced by the alignment of the polymer chains along the fibers' axis. Copyright © 2013 Wiley Periodicals, Inc.
Keywords: Capillary rheometer; Melt-compounding; Multi-walled nanotubes; Nanostructured polymers; Postprocessing methods; Thermal and electrical properties; Thermoplastic fibers; Twin screw extrusion; Carbon; Chains; Electric properties; Extrusion; Fibers; Mechanical properties; Multiwalled carbon nanotubes (MWCN); Polyamides; Polymers; X ray diffraction; Spinning (fibers)

On the effect of the orientation of sheet rolling direction in shot peen forming - Gariépy, A.; Larose, S.; Perron, C.; Bocher, P.; Lévesque, M. (Journal of Materials Processing Technology, 2013)
Peen forming is commonly used in the aerospace industry to shape large and thin panels, such as wing skins. This manufacturing process uses shot peening to introduce unbalanced compressive stresses near the surface of the component. These stresses tend to bend the panel and, when optimized, lead to the desired contour. Sheet materials often exhibit both elastic and plastic anisotropy, which can alter the development of curvatures. Since peen forming relies on compressive stresses to upset equilibrium, resulting curvatures may also be affected by initial stresses in the part. In this work, the influence of the rolling direction orientation with respect to the sample was investigated experimentally and numerically for the first time for aluminium alloy 2024-T3 specimens. Although maximum deflections were only slightly dependent on the rolling direction orientation, it was found that radii of curvature varied by as much as 10% with respect to this parameter. Finite element simulations allowed quantification of the individual effects of non-equibiaxial initial stresses and elastic orthotropy. It was found that these factors can significantly influence curvature development. Comparison of experimental and numerical results suggested that plastic anisotropy should also be taken into account in future studies. The tools developed in this study show promises for the accurate prediction of peen forming process for large scale components. © 2013 Elsevier B.V. All rights reserved.
Keywords: 2024-T3; Accurate prediction; Finite Element; Finite element simulations; Initial stress; Manufacturing process; Maximum deflection; Numerical results; Orthotropy; Peen forming; Plastic anisotropy; Radii of curvature; Rolling direction; Sheet material; Sheet rolling; Shot peen; Wing skins; Aerospace industry; Anisotropy; Compressive stress; Residual stresses; Shot peening

Fabrication of binary opal lattices in microfluidic devices - Malekpourkoupaei, A.; Kostiuk, L.W.; Harrison, D.J. (Chemistry of Materials, 2013)
We have studied growth and fabrication of opal lattices made from polystyrene and silica particles by an on-chip colloidal self-assembly (CSA) approach. An optical microscopy method was used to analyze the lattice growth behavior. A mathematical model was also adopted and modified to describe the growth behavior of the silica system. On the basis of these studies, silica and polystyrene systems demonstrate different growth dynamics that originate from a sedimentation process in the microfluidic chip reservoir fractionating large and small particles. Binary lattices of silica particles were fabricated by a periodic chip rotation method. The effect of particle number ratio on the opal stoichiometry was also studied for the polystyrene system. By increasing the number ratio from 2.5 to 11, different structural stoichiometries were achieved. © 2013 American Chemical Society.
Keywords: Colloidal self-assembly; Micro-fluidic devices; Microfluidic chip; Particle numbers; Protein separations; Rotation methods; Sedimentation process; Silica particles; Fabrication; Fluidic devices; Mathematical models; Microfluidics; Nanopores; Polystyrenes; Self assembly; Stoichiometry; Silica

Tocopherol activity correlates with its location in a membrane: A new perspective on the antioxidant vitamin e - Marquardt, D.; Williams, J.A.; Kučerka, N.; Atkinson, J.; Wassall, S.R.; Katsaras, J.; Harroun, T.A. (Journal of the American Chemical Society, 2013)
We show evidence of an antioxidant mechanism for vitamin E which correlates strongly with its physical location in a model lipid bilayer. These data address the overlooked problem of the physical distance between the vitamin's reducing hydrogen and lipid acyl chain radicals. Our combined data from neutron diffraction, NMR, and UV spectroscopy experiments all suggest that reduction of reactive oxygen species and lipid radicals occurs specifically at the membrane's hydrophobic-hydrophilic interface. The latter is possible when the acyl chain "snorkels" to the interface from the hydrocarbon matrix. Moreover, not all model lipids are equal in this regard, as indicated by the small differences in vitamin's location. The present result is a clear example of the importance of lipid diversity in controlling the dynamic structural properties of biological membranes. Importantly, our results suggest that measurements of aToc oxidation kinetics, and its products, should be revisited by taking into consideration the physical properties of the membrane in which the vitamin resides. © 2013 American Chemical Society.
Keywords: Antioxidant mechanisms; Hydrocarbon matrix; Hydrophobic-hydrophilic; Lipid acyl-chains; Measurements of; Oxidation kinetics; Physical locations; Reactive oxygen species; Cytology; Lipid bilayers; Neutron diffraction; Ultraviolet spectroscopy; Physical addresses; alpha tocopherol; hydrocarbon; hydrogen; hydroxyl group; reactive oxygen metabolite; tocopherol; antioxidant activity; hydration; hydrophilicity; hydrophobicity; lipid bilayer; lipid membrane; lipid oxidation; membrane structure; neutron diffraction; nuclear magnetic resonance spectroscopy; review; ultraviolet spectroscopy

Modeling noncovalent radical-molecule interactions using conventional density-functional theory: Beware erroneous charge transfer - Johnson, E.R.; Salamone, M.; Bietti, M.; Dilabio, G.A. (The Journal of Physical Chemistry A, 2013)
Conventional density-functional theory (DFT) has the potential to overbind radical-molecule complexes because of erroneous charge transfer. We examined this behavior by exploring the ability of various DFT approximations to predict fractional charge transfer and by quantifying the overbinding in a series of complexes. It is demonstrated that too much charge is transferred from molecules to radicals when the radical singly unoccupied molecular orbitals are predicted to be erroneously too low in energy relative to the molecule highest occupied molecular orbitals, leading to excessive Coulombic attraction. In this respect, DFT methods formulated with little or no Hartree-Fock exchange perform most poorly. The present results illustrate that the charge-transfer problem is much broader than may have been previously expected and is not limited to conventional (i.e., molecule-molecule) donor-acceptor complexes. © 2013 American Chemical Society.
Keywords: Coulombic attractions; DFT method; Donor-acceptor complex; Fractional charges; Hartree-Fock exchanges; Highest occupied molecular orbital; Noncovalent; Charge transfer; Density functional theory; Molecular orbitals; Molecules

Does a prestellar core always become protostellar? Tracing the evolution of cores from the prestellar to protostellar phase - Anathpindika, S.; Francesco, J.D. (Monthly Notices of the Royal Astronomical Society, 2013)
Recently, a subset of starless cores whose thermal Jeans mass is apparently overwhelmed by the mass of the core has been identified, e.g. the core L183. In the literature, massive cores such as this one are often referred to as 'super-Jeans cores'. As starless cores are perhaps on the cusp of forming stars, a study of their dynamics will improve our understanding of the transition from the prestellar to the protostellar phase. In this work, we use non-magnetic polytropes belonging originally to the family of the Isothermal sphere. For the purpose, perturbations were applied to individual polytropes, first by replacing the isothermal gas with a gas that was cold near the centre of the polytrope and relatively warm in the outer regions, and secondly, through a slight compression of the polytrope by raising the external confining pressure. Using this latter configuration, we identify thermodynamic conditions under which a core is likely to remain starless. In fact, we also argue that the attribute 'super-Jeans' is subjective and that these cores do not formally violate the Jeans stability criterion. On the basis of our test results, we suggest that gas temperature in a star-forming cloud is crucial towards the formation and evolution of a core. Simulations in this work were performed using the particle-based smoothed particle hydrodynamics algorithm. However, to establish numerical convergence of the results we suggest similar tests with a grid scheme, such as the adaptive mesh refinement. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Disorder and defect formation mechanisms in molecular-beam-epitaxy grown silicon epilayers - Akbari-Sharbaf, A.; Baribeau, J.-M.; Wu, X.; Lockwood, D.J.; Fanchini, G. (Thin Solid Films, 2013)
We investigate the role of disorder, stress and crystallite size in determining the density of defects in disordered and partially ordered silicon thin films deposited at low or moderate temperatures by molecular beam epitaxy. We find that the paramagnetic defect density measured by electron spin resonance (ESR) is strongly dependent on the growth temperature of the films, decreasing from ~ 2·1019 cm- 3 at 98 C to ~ 1·10 18 cm- 3 at 572 C. The physical nature of the defects is strongly dependent on the range of order in the films: ESR spectra consistent with dangling bonds in an amorphous phase are observed at the lowest temperatures, while the ESR signal gradually becomes more anisotropic as medium-range order improves and the stress level (measured both by X-ray diffraction and Raman spectroscopy) is released in more crystalline films. Anisotropic ESR spectra consistent with paramagnetic defects embedded in an epitaxial phase are observed at the highest growth temperature (572 C).
Keywords: Molecular beam epitaxy; Disordered silicon; Defects; Electron spin resonance; Microstructure

Nickel, cobalt, and manganese oxide composite as an electrode material for electrochemical supercapacitors - Wang, G.; Liu, L.; Zhang, L.; Zhang, J. (Ionics, 2013)
A composite material, Ni1/3Co1/3Mn1/3(OH)2, is synthesized by chemical precipitation method for supercapacitors' electrode material. Physical characterizations using x-ray diffraction, energy-dispersive x-ray, and scanning electron microscopy show that Ni1/3Co1/3Mn1/3(OH)2 possesses an amorphous structure and higher specific surface area (268. 5 m2 g-1), which lead to a high initial specific capacitance of 1,403 F g-1 in the potential window of 0-1. 5 V. It may be a potential electrode material for future supercapacitor when its cycling stability and rate performance are addressed. © 2013 Springer-Verlag Berlin Heidelberg.
Keywords: Co-oxides; Composite electrode; Electrochemical supercapacitor; Mn oxides; Ni oxide; Capacitors; Manganese; Nickel; Precipitation (chemical); Scanning electron microscopy; X ray diffraction; Electrochemical electrodes

Using small-angle neutron scattering to detect nanoscopic lipid domains - Pan, J.; Heberle, F.A.; Petruzielo, R.S.; Katsaras, J. (Chemistry and Physics of Lipids, 2013)
The cell plasma membrane is a complex system, which is thought to be capable of exhibiting non-random lateral organization. Studies of live cells and model membranes have yielded mechanisms responsible for the formation, growth, and maintenance of nanoscopic heterogeneities, although the existence and mechanisms that give rise to these heterogeneities remain controversial. Small-angle neutron scattering (SANS) is a tool ideally suited to interrogate lateral heterogeneity in model membranes, primarily due to its unique spatial resolution (i.e., ∼5-100 nm) and its ability to resolve structure with minimal perturbation to the membrane. In this review we examine several methods used to analyze the SANS signal arising from freely suspended unilamellar vesicles containing lateral heterogeneity. Specifically, we discuss an analytical model for a single, round domain on a spherical vesicle. We then discuss a numerical method that uses Monte Carlo simulation to describe systems with multiple domains and/or more complicated morphologies. Also discussed are several model-independent approaches that are sensitive to membrane heterogeneity. The review concludes with several recent applications of SANS to the study of membrane raft mixtures. © 2013 Elsevier Ireland Ltd. All rights reserved.
Keywords: lipid; cell membrane; lipid composition; membrane model; Monte Carlo method; morphology; neutron scattering; phase separation; priority journal; review

Immunization against a saccharide epitope accelerates clearance of experimental gonococcal infection - Gulati, S.; Zheng, B.; Reed, G.W.; Su, X.; Cox, A.D.; St. Michael, F.; Stupak, J.; Lewis, L.A.; Ram, S.; Rice, P.A. (PLoS Pathogens, 2013)
The emergence of ceftriaxone-resistant strains of Neisseria gonorrhoeae may herald an era of untreatable gonorrhea. Vaccines against this infection are urgently needed. The 2C7 epitope is a conserved oligosaccharide (OS) structure, a part of lipooligosaccharide (LOS) on N gonorrhoeae. The epitope is expressed by 94% of gonococci that reside in the human genital tract (in vivo) and by 95% of first passaged isolates. Absence of the 2C7 epitope shortens the time of gonococcal carriage in a mouse model of genital infection. To circumvent the limitations of saccharide immunogens in producing long lived immune responses, previously we developed a peptide mimic (called PEP1) as an immunologic surrogate of the 2C7-OS epitope and reconfigured it into a multi-antigenic peptide, (MAP1). To test vaccine efficacy of MAP1, female BALB/c mice were passively immunized with a complement-dependent bactericidal monoclonal antibody specific for the 2C7 epitope or were actively immunized with MAP1. Mice immunized with MAP1 developed a TH1-biased anti-LOS IgG antibody response that was also bactericidal. Length of carriage was shortened in immune mice; clearance occurred in 4 days in mice passively administered 2C7 antibody vs. 6 days in mice administered control IgG3λ mAb in one experiment (p = 0.03) and 6 vs. 9 days in a replicate experiment (p = 0.008). Mice vaccinated with MAP1 cleared infection in 5 days vs. 9 days in mice immunized with control peptide (p = 0.0001 and p = 0.0002, respectively in two replicate experiments). Bacterial burden was lower over the course of infection in passively immunized vs. control mice in both experiments (p = 0.008 and p = 0.0005); burdens were also lower in MAP1 immunized mice vs. controls (p<0.0001) and were inversely related to vaccine antibodies induced in the vagina (p = 0.043). The OS epitope defined by mAb 2C7 may represent an effective vaccine target against gonorrhea, which is rapidly becoming incurable with currently available antibiotics. © 2013 Gulati et al.
Keywords: bacterial vaccine; glycosyltransferase; immunoglobulin A; immunoglobulin G; immunoglobulin M; monoclonal antibody 2C7; multi antigenic peptide 1; unclassified drug; article; bacterial clearance; bactericidal activity; colony forming unit; controlled study; enzyme linked immunosorbent assay; female; fractionation; gonorrhea; human; immune response; immunization; mouse; Neisseria gonorrhoeae; nonhuman; passive immunization; polymerase chain reaction; serum bactericidal antibody assay

Single-mode 2.65 μm InGaAsSb/AlInGaAsSb laterally coupled distributed-feedback diode lasers for atmospheric gas detection - Briggs, R.M.; Frez, C.; Bagheri, M.; Borgentun, C.E.; Gupta, J.A.; Witinski, M.F.; Anderson, J.G.; Forouhar, S. (Optics Express, 2013)
We demonstrate index-coupled distributed-feedback diode lasers at 2.65 μm that are capable of tuning across strong absorption lines of HDO and other isotopologues of H2O. The lasers employ InGaAsSb/AlInGaAsSb multi-quantum-well structures grown by molecular beam epitaxy on GaSb, and single-mode emission is generated using laterally coupled second-order Bragg gratings etched alongside narrow ridge waveguides. We verify nearcritical coupling of the gratings by analyzing the modal characteristics of lasers of different length. With an emission facet anti-reflection coating, 2-mm-long lasers exhibit a typical current threshold of 150 mA at 20 °C and are capable of emitting more than 25 mW in a single longitudinal mode, which is significantly higher than the output power reported for losscoupled distributed-feedback lasers operating at similar wavelengths. © 2013 Optical Society of America.
Keywords: Absorption lines; Current thresholds; Distributed-feedback; Gas detection; InGaAsSb; Isotopologues; Modal characteristics; Multi-quantum well structures; Output power; Second orders; Single longitudinal mode; Single mode; Single mode emission; Molecular beam epitaxy; Ridge waveguides; Semiconductor lasers; Distributed feedback lasers

Nonlocal effect and dimensions of Cooper pairs measured by low-energy muons and polarized neutrons in type-I superconductors - Kozhevnikov, V.; Suter, A.; Fritzsche, H.; Gladilin, V.; Volodin, A.; Moorkens, T.; Trekels, M.; Cuppens, J.; Wojek, B.M; Prokscha, T.; Morenzoni, E.; Nieuwenhuys, G.J.; et al. (Physical Review B - Condensed Matter and Materials Physics, 2013)
The Pippard coherence length ξ0 (the size of a Cooper pair) in two extreme type-I superconductors (In and Sn) was determined directly through high-resolution measurement of the nonlocal electrodynamic effect combining low-energy muon spin rotation spectroscopy and polarized neutron reflectometry. The renormalization factor Z=mcp*/2m (mcp* and m are the mass of the Cooper pair and the electron, respectively) resulting from the electron-phonon interaction, and the temperature-dependent London penetration depth λL(T) were determined as well. An expression linking ξ0, Z, and λL(0) is introduced and experimentally verified. This expression allows one to determine experimentally the Pippard coherence length in any superconductor, independent of whether the superconductor is local or nonlocal, conventional or unconventional. © 2013 American Physical Society.

A minocycline derivative reduces nerve injury-induced allodynia, LPS-induced prostaglandin E2 microglial production and signaling via toll-like receptors 2 and 4 - Bastos, L.F.S.; Godin, A.M.; Zhang, Y.; Jarussophon, S.; Ferreira, B.C.S.; Machado, R.R.; Maier, S.F.; Konishi, Y.; de Freitas, R.P.; Fiebich, B.L.; Watkins, L.R.; Coelho, M.M.; et al. (Neuroscience Letters, 2013)
Many studies have shown that minocycline, an antibacterial tetracycline, suppresses experimental pain. While minocycline's positive effects on pain resolution suggest that clinical use of such drugs may prove beneficial, minocycline's antibiotic actions and divalent cation (Ca2+; Mg2+) chelating effects detract from its potential utility. Thus, we tested the antiallodynic effect induced by a non-antibacterial, non-chelating minocycline derivative in a model of neuropathic pain and performed an initial investigation of its anti-inflammatory effects in vitro. Intraperitoneal minocycline (100mg/kg) and 12S-hydroxy-1,12-pyrazolinominocycline (PMIN; 23.75mg/kg, 47.50mg/kg or 95.00mg/kg) reduce the mechanical allodynia induced by chronic constriction injury of mouse sciatic nerve. PMIN reduces the LPS-induced production of PGE2 by primary microglial cell cultures. Human embryonic kidney cells were transfected to express human toll-like receptors 2 and 4, and the signaling via both receptors stimulated with PAM3CSK4 or LPS (respectively) was affected either by minocycline or PMIN. Importantly, these treatments did not affect the cell viability, as assessed by MTT test. Altogether, these results reinforce the evidence that the anti-inflammatory and experimental pain suppressive effects induced by tetracyclines are neither necessarily linked to antibacterial nor to Ca2+ chelating activities. This study supports the evaluation of the potential usefulness of PMIN in the management of neuropathic pain, as its lack of antibacterial and Ca2+ chelating activities might confer greater safety over conventional tetracyclines. © 2013 Elsevier Ireland Ltd.
Keywords: calcium; divalent cation; hydroxy 1,12 pyrazolinominocycline; magnesium ion; minocycline; prostaglandin E2; pyrazoline derivative; toll like receptor 2; toll like receptor 4; unclassified drug; allodynia; animal cell; animal experiment; animal model; animal tissue; antibacterial activity; antiinflammatory activity; article; cell viability; chelation; controlled study; female; genetic transfection; human; in vitro study; kidney cell; microglia; mouse; nerve injury; neuropathic pain; nonhuman; priority journal; sham procedure; single drug dose; treatment duration; treatment outcome; Animals; Anti-Inflammatory Agents, Non-Steroidal; Cells, Cultured; Dinoprostone; Female; Humans; Hyperalgesia; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Microglia; Minocycline; Neuralgia; Physical Stimulation; Rats; Rats, Wistar; Sciatic Nerve; Signal Transduction; Toll-Like Receptor 2; Toll-Like Receptor 4; Touch

Incommensurate dynamic correlations in the quasi-two-dimensional spin liquid BiCu2PO6 - Plumb, K.W.; Yamani, Z.; Matsuda, M.; Shu, G.J.; Koteswararao, B.; Chou, F.C.; Kim, Y.-J. (Physical Review B - Condensed Matter and Materials Physics, 2013)
We report detailed inelastic neutron-scattering measurements on single crystals of the frustrated two-leg ladder BiCu2PO6, whose ground state is described as a spin liquid phase with no long-range order down to 6 K. Two branches of steeply dispersing long-lived spin excitations are observed with excitation gaps of Δ1=1.90(9) meV and Δ2=3.95(8) meV. Significant frustrating next-nearest-neighbor interactions along the ladder leg drive the minimum of each excitation branch to incommensurate wave vectors ζ1=0.574π and ζ2=0.553π for the lower and upper energy branches, respectively. The temperature dependence of the excitation spectrum near the gap energy is consistent with thermal activation into singly and doubly degenerate excited states. The observed magnetic excitation spectrum as well as earlier thermodynamic data could be consistently explained by the presence of strong anisotropic interactions in the ground-state Hamiltonian. © 2013 American Physical Society.

Interfacial vs. internalwater transport resistance of sulfonated hydrocarbon proton-exchange membranes - Zhao, N.; Edwards, D.; Shi, Z.; Holdcroft, S. (ECS Electrochemistry Letters, 2013)
Liquid-Vapor Water Permeation (LVP) through sulfonated poly(etheretherketone) (sPEEK) proton exchange membranes, measured upon exposure of membranes to liquid water on one side and water vapor on the other, is lower than for Nafion membranes. Thickness-dependent measurements reveal that both internal and interfacial resistances to water transport are larger for sPEEK membranes, despite sPEEK membranes possessing larger water contents and possessing more hydrophilic surfaces. This report brings to attention the importance of organized hydrophilic domains on net water transport, not just within the membrane, which is common knowledge, but also at its surface. © 2013 The Electrochemical Society.
Keywords: Common knowledge; Hydrophilic domains; Hydrophilic surfaces; Interfacial resistances; Proton exchange membranes; Proton-exchange membrane; Transport resistance; Water permeation; Hydrophilicity; Proton exchange membrane fuel cells (PEMFC); Vapors; Membranes

Modal survey test and model correlation of the CASSIOPE spacecraft - Wickramasinghe, V.; Chen, Y.; Zimcik, D.; Tremblay, P.; Dahl, H.; Walkty, I. (Experimental Techniques, 2013)
A comprehensive modal survey test based on multi-input multi-output experimental modal analysis techniques was conducted on the flight model of the CASSIOPE spacecraft in the final stages of integration, which included all of the payload and bus instruments and electronics boxes. The multiple-input excitation for the spacecraft was generated using two portable electrodynamic modal shakers installed on the top and bottom of the spacecraft to distribute the excitation energy and the response was measured using 81 miniature accelerometers. Advanced modal analysis software was used to extract modal parameters from the measured data and critical modes were compared with predictions from the finite element model. Most modes identified through the experimental data compared favorably with the predictions. Nevertheless, some differences were large enough to require iterative update of the finite element model. The structural dynamics information from the updated finite element model was used to plan the mechanical vibration qualification test and predict the response of the spacecraft to the launch vehicle environmental loads through coupled loads analysis to provide confidence in the structural integrity of the spacecraft design. This paper describes the details of the methodology used to perform the successful experimental modal test to efficiently extract the critical modes of the spacecraft to correlate with the model. © 2011, Society for Experimental Mechanics.
Keywords: Analysis softwares; Coupled loads analysis; Environmental loads; Experimental modal analysis; Experimental modal tests; Modal test; Multi-input multi-output; Qualification test; Finite element method; Forecasting; Iterative methods; MIMO systems; Modal analysis; Structural dynamics; Surveys; Vibrations (mechanical); Spacecraft

Prioritization of therapeutic targets of inflammation using proteomics, bioinformatics, and in silico cell-cell interactomics - Haqqani, A.S.; Stanimirovic, D.B. (Methods in Molecular Biology, 2013)
Leukocyte extravasation is a multistep process, involving the movement of leukocytes out of the circulatory system, through vascular endothelium and to the site of tissue damage or infection. Protein-protein interactions play key roles in the extravasation process and have been attractive therapeutic targets for inhibiting inflammation using blocking (or neutralizing) antibodies. These targets include protein-protein interactions between cytokines (or chemokines) and their receptors on leukocytes and between adhesions molecules involving leukocyte-endothelium contacts. A number of therapeutics against these targets are currently used in clinic for treatment of inflammatory disorders, however, they are associated with side-effects partly due to the off-target actions (i.e., nonspecific targets). There is a need for novel targets involved in the leukocyte extravasation process that are specific to leukocyte subsets or to individual inflammatory disorder, and are amenable for drug development (i.e., duggable). In this chapter, we describe a methodology to identify novel "druggable" targets involving protein-protein interactions between activated leukocytes and endothelial cells using a combination of proteomics, bioinformatics and in silico interactomics. The result is a prioritized list of protein-protein interactions in a network consisting of leukocyte-endothelial cell communication and contacts. These prioritized targets can be pursued for the development of therapeutics such as neutralizing antibodies and for their validation through preclinical testing. The method described here provides the workflow to identify and clinically target important cell-cell interactions that are specific/selective for particular inflammatory disorders and to improve currently available therapies. © 2013 Springer Science+Business Media, LLC.
Keywords: intercellular adhesion molecule 1; neutralizing antibody; vascular cell adhesion molecule 1; amino acid sequence; article; bioinformatics; cell activation; cell communication and cell contact; cell interaction; cell surface; computer program; endothelium cell; human; human cell; inflammation; leukocyte; liquid chromatography; mass spectrometry; priority journal; protein analysis; protein folding; protein protein interaction; protein secretion; proteomics; T lymphocyte activation

Journal Impact Factors: Their relevance and their influence on society-published scientific journalsk - Putirka, K.; Kunz, M.; Swainson, I.; Thomson, J. (American Mineralogist, 2013)
We examine the nature and temporal trends of science journal publishing, and seek to explain why some journals have higher Journal Impact Factors (JIF) than others. The investigation has implications for how we assess the importance of scientific contributions. National Laboratories run by the U.S. Department of Energy, for example, compare JIF across disciplines, while some academic institutions look at JIF when evaluating publication records. Problematic to these policies are several results, which have long been known in the medical and biological sciences, and are shown here to apply to the Earth sciences as well. In particular, citations are distributed almost logarithmically in any given issue of a journal, and so JIFs say nothing about the actual number of citations acquired by any given paper. In the area of mineralogy and petrology, for example, 25% of articles in a typical issue will capture >50% of all citations that accrue to that issue. For some issues the asymmetry is greater; we use such citation asymmetry to develop a classification for journals as "super elite," "elite," "influential," and "minor." We also find that JIFs are inherently larger for large disciplines, in part because as the size of a discipline increases (as measured by total papers published), the top journals benefit to a greater extent than other journals. For this and other reasons, JIF cannot be compared across disciplines. A heretofore unknown and disconcerting result is the incredible growth in JIFs for commercially published journals compared to their society-published counterparts-a growth that coincides with the advent of electronic distribution models (e.g., bundling) that were instituted by commercial publishers at the beginning of the 21st century. Journals, which only a decade ago had similar JIFs, and were viewed as being scientifically equivalent, now have very different JIFs. These contrasts may nucleate feedback loops (as authors look to higher JIF journals in which to publish) that threaten the health of society-published journals. Our analysis however, shows that in spite of growing contrasts in JIF, many society-published journals still provide a greater value (JIF/cost) compared to their commercially published counterparts. While we acknowledge that citations and citation rates can be useful tools to compare scientific influence and importance, the results of this and other bibliometric studies cause us to conclude that in the evaluation of science and scientists, it is a grave error to substitute numerical values for human judgment. And if professional societies are to continue to play a significant role in science publication, it is incumbent upon scientists-now more than ever-to send their best works to society-published journals.
Keywords: asymmetric information; bibliography; geochemistry; mineralogy; petrology; publishing

Instantaneous in-flame measurement of soot volume fraction, primary particle diameter, and aggregate radius of gyration via auto-compensating laser-induced incandescence and two-angle elastic light scattering - Crosland, B.M.; Thomson, K.A.; Johnson, M.R. (Applied Physics B: Lasers and Optics, 2013)
A new combination of soot diagnostics employing two-angle elastic light scattering and laser-induced incandescence is described that is capable of producing non-intrusive, instantaneous, and simultaneous, in situ measurements of soot volume fraction, primary particle size, and aggregate radius of gyration within flames. Controlled tests of the new apparatus on a well-characterized laminar flame show good agreement with existing measurements in the literature. From a detailed and comprehensive Monte Carlo uncertainty analysis of the results, it was found that the uncertainty in all three measured parameters is dominated by knowledge of soot properties and aggregation behavior. The soot volume fraction uncertainty is dominated by uncertainty in the soot refractive index light absorption function; the primary particle diameter uncertainty is dominated by uncertainty in the fractal prefactor; while the uncertainty in the aggregate radius of gyration is dominated by the uncertainty in the width of the distribution of aggregate sizes.

Fecal source tracking in water using a mitochondrial DNA microarray - Vuong, N.-M.; Villemur, R.; Payment, P.; Brousseau, R.; Topp, E.; Masson, L. (Water Research, 2013)
A mitochondrial-based microarray (mitoArray) was developed for rapid identification of the presence of 28 animals and one family (cervidae) potentially implicated in fecal pollution in mixed activity watersheds. Oligonucleotide probes for genus or subfamily-level identification were targeted within the 12S rRNA - Val tRNA - 16S rRNA region in the mitochondrial genome. This region, called MI-50, was selected based on three criteria: 1) the ability to be amplified by universal primers 2) these universal primer sequences are present in most commercial and domestic animals of interest in source tracking, and 3) that sufficient sequence variation exists within this region to meet the minimal requirements for microarray probe discrimination. To quantify the overall level of mitochondrial DNA (mtDNA) in samples, a quantitative-PCR (Q-PCR) universal primer pair was also developed. Probe validation was performed using DNA extracted from animal tissues and, for many cases, animal-specific fecal samples. To reduce the amplification of potentially interfering fish mtDNA sequences during the MI-50 enrichment step, a clamping PCR method was designed using a fish-specific peptide nucleic acid. DNA extracted from 19 water samples were subjected to both array and independent PCR analyses. Our results confirm that the mitochondrial microarray approach method could accurately detect the dominant animals present in water samples emphasizing the potential for this methodology in the parallel scanning of a large variety of animals normally monitored in fecal source tracking. © 2012 Elsevier Ltd.
Keywords: DNA micro-array; Fecal; PCR clamping; Peptide nucleic acid; Quantitative PCR; Source tracking; DNA; Extraction; Fish; Mitochondria; Oligonucleotides; Peptides; Probes; RNA; Tissue; Water pollution; Polymerase chain reaction; mitochondrial DNA; RNA 12S; RNA 16S; transfer RNA; array; deer; discriminant analysis; domestic species; environmental monitoring; genome; identification method; mitochondrial DNA; nucleic acid; polymerase chain reaction; watershed; animal tissue; article; cat; controlled study; cow; coyote; deer; DNA extraction; DNA microarray; DNA sequence; dog; duck; emu; fecal coliform; feces; feces analysis; gene amplification; gene sequence; gene targeting; genetic identification; genetic variability; goat; horse; human; limit of detection; moose; mouse; muskrat; nonhuman; nucleotide sequence; oligonucleotide probe; ostrich; pigeon; polymerase chain reaction; poultry; priority journal; quail; quantitative analysis; rabbit; raccoon; reindeer; sheep; swine; turkey (bird); water pollution; water sampling; watershed; Animals; DNA, Mitochondrial; Enterobacteriaceae; Environmental Monitoring; Feces; Humans; Oligonucleotide Array Sequence Analysis; RNA, Ribosomal; RNA, Ribosomal, 16S; RNA, Transfer; Species Specificity; Water Pollutants; Animalia; Cervidae

Effects of SWCNTs on mechanical and thermal performance of epoxy at elevated temperatures - Ashrafi, B.; Backman, D.; Johnston, A.; Martinez-Rubi, Y.; Simard, B. (Journal of Materials Science, 2013)
A property which limits the breadth of application of thermoset polymers and their composites is their relatively low maximum operating temperatures. This work investigates the potential application of both functionalized single-walled carbon nanotubes (f-SWCNTs) based on negative charging, and unfunctionalized SWCNTs (u-SWCNTs) to increase the mechanical and thermal performance of a high-temperature aerospace-grade epoxy with a glass transition temperature of approximately 270 C. Thermal and mechanical properties of the baseline epoxy and nanocomposites containing a low content of SWCNTs (0.2 % by weight) were characterized through thermogravimetric analyses, tensile tests, and dynamic mechanical analyses. Tensile tests were performed both at room temperature and at 80 C. Further, room temperature tensile tests were performed on untreated and heat-treated specimens. The heat treatment was performed at 300 C, slightly above the resin glass transition temperature. Results demonstrate that f-SWCNTs are effective in improving the mechanical and thermal performance of the epoxy. No significant improvement was observed for u-SWCNT nanocomposites. For the nanocomposite with f-SWCNTs, the ultimate tensile strength and strain to failure at room temperature (80 C) increased by 20 % (8 %) and 71 % (77 %), respectively, as compared to the baseline epoxy. The f-SWCNT nanocomposite, unlike other examined materials, exhibited a stress-strain necking behavior at 80 C, an indication of increased ductility. After heat treatment, these properties further improved relative to the neat epoxy (160 % increase in ultimate tensile strength and 270 % increase in strain to failure). This work suggests the potential to utilize f-SWCNTs based on negative charging to enhance high-temperature thermoset performance. © 2013 Her Majesty the Queen in Right of Canada.
Keywords: After-heat treatment; Elevated temperature; Heat-treated specimens; Operating temperature; Thermal and mechanical properties; Thermal Performance; Thermoset polymers; Ultimate tensile strength; Dynamic mechanical analysis; Glass; Heat treatment; Mechanical properties; Single-walled carbon nanotubes (SWCN); Tensile strength; Tensile testing; Thermogravimetric analysis; Thermosets; Nanocomposites

Nafion®/ODF-silica composite membranes for medium temperature proton exchange membrane fuel cells - Treekamol, Y.; Schieda, M.; Robitaille, L.; MacKinnon, S.M.; Mokrini, A.; Shi, Z.; Holdcroft, S.; Schulte, K.; Nunes, S.P. (Journal of Power Sources, 2013)
A series of composite membranes were prepared by dispersing fluorinated polyoxadiazole oligomer (ODF)-functionalized silica nanoparticles in a Nafion® matrix. Both melt-extrusion and solvent casting processes were explored. Ion exchange capacity, conductivity, water uptake and dimensional stability, thermal stability and morphology were characterized. The inclusion of functionalized nanoparticles proved advantageous, mainly due to a physical crosslinking effect and better water retention, with functionalized nanoparticles performing better than the pristine silica particles. For the same filler loading, better nanoparticle dispersion was achieved for solvent-cast membranes, resulting in higher proton conductivity. Filler agglomeration, however, was more severe for solvent-cast membranes at loadings beyond 5 wt.%. The composite membranes showed excellent thermal stability, allowing for operation in medium temperature PEM fuel cells. Fuel cell performance of the composite membranes decreases with decreasing relative humidity, but good performance values are still obtained at 34% RH and 90 °C, with the best results obtained for solvent cast membranes loaded with 10 wt.% ODF-functionalized silica. Hydrogen crossover of the composite membranes is higher than that for pure Nafion® membranes, possibly due to porosity resulting from suboptimal particle-matrix compatibility. © 2013 [Author/Employing Institution].

Multivariate factor analysis of heavy minerals concentrate from Athabasca oil sands tailings by X-ray photoelectron spectroscopy - Marshall, Gregory M.; Kingston, David M.; Moran, Kevin; Mercier, Patrick H. J. (Surface and Interface Analysis, 2013)
Multivariate factor analysis of X-ray photoelectron spectroscopy data acquired from Athabasca oil sands heavy minerals concentrate was used to identify the primary mineral components and their physical associations. Using large-area spectroscopy, a principal components analysis (PCA) and Varimax rotation of the PCA spectral loadings matrix demonstrated that the most significant factors index the mineral chemistry by virtue of the within-factor spectral correlations. Analysis of the Varimax rotated factor scores indicated the physical character of several mineral associations. Emphasis is placed on the high-value materials, namely, zircon and the titanium-bearing minerals. In spectral imaging mode, Varimax rotation in the spatial domain applied to a PCA noise-reduced data reconstruction was used to render component images illustrating the spatial distribution of selected mineral chemistries. The component images also revealed evidence of surface species consistent with pyrite weathering. Data are supported with optical microscopy and energy-dispersive X-ray spectroscopy. Our work demonstrates the utility of multivariate spectroscopic techniques in the analysis of complex mineral chemistry.
Keywords: multivariate analysis; XPS chemical imaging; oil sands; mineralogy; Varimax rotation

Performance of a Carboxydothermus hydrogenoformansimmobilizing membrane reactor for syngas upgrading into hydrogen - Zhao, Y.; Haddad, M.; Cimpoia, R.; Liu, Z.; Guiot, S.R. (International Journal of Hydrogen Energy, 2013)
Hydrogen conversion of CO by a pure culture of Carboxydothermus hydrogenoformans was investigated and optimized in a lab-scale hollow fiber membrane bioreactor (HFMBR). The reactor was operated under strict anaerobic, extremely thermophilic (70 °C) conditions with a continuous supply of gas, for four months. Reactor performance was evaluated under various operational conditions, such as liquid velocity (vliq) (13, 65 and 130 m h -1), temperature (70, 65, and 60 °C), CO pressure (from 1 to 2.5 atm) and CO loading rate (from 1.3 to 16:5 mol Lrxr -1 d-1). Overall, results indicated a relatively constant H2 yield of 92 ± 4% (mol mol-1) regardless of the operational condition tested. Permeation across the colonized membrane was improved by three orders of magnitude as compared to the abiotic membrane, because of dissolved CO concentration was constantly maintained low in the liquid on the shell side of the membrane as continually depleted by the microorganisms. Once the biofilm was sufficiently developed, a maximum CO conversion activity of 0.44 mol CO g-1 volatile suspended solid (VSS) d-1 was achieved at a pCO of 2 atm or above and a vliq of 65 m h-1. However, this highest activity represented only 15% of the maximal activity potential of the strain under non-limiting conditions, attributed to the low concentration of dissolved CO (0.01-0.07 mM) present in the HFMBR liquid. Higher vliq (130 m h-1) produced shearing stress, which detached a significant portion of the biofilm from the membrane, and/or prevented less sessile growth (57% total biomass as biofilm, as opposed to 84-86% at lower vliq). One may deduce from this work that the volumetric CO conversion performance of such a membrane bioreactor would be at the most in the range of 5 mol CO Lrxr -1 d-1. Overall, the CO conversion performance in the HFMBR was biokinetically limited, when not limited by gaseliquid mass transfer. Additionally, over time, membrane fouling and aging decreased membrane permeability such that the CO transfer rate would be the most limiting factor in the long run. Crown Copyright © 2012, Hydrogen Energy Publications, LLC.
Keywords: Abiotic membranes; Carboxydothermus hydrogenoformans; CO conversion; Co loading; Dissolved co; Hollow fiber membrane bioreactor; Hollow fiber membranes; Liquid velocities; Low concentrations; Membrane bioreactor; Membrane permeability; Membrane reactor; Operational conditions; Pure culture; Reactor performance; Sessile growths; Shearing stress; Shell-side; Syn-gas; Three orders of magnitude; Total biomass; Transfer rates; Volatile suspended solids; Biofilms; Bioreactors; Carbon monoxide; Fischer-Tropsch synthesis; Fouling; Hydrogen; Internet protocols; Liquids; Loading; Mass transfer; Membrane fouling; Synthesis gas; Membranes

A review on the laminar flame speed and ignition delay time of Syngas mixtures - Lee, H.C.; Jiang, L.Y.; Mohamad, A.A. (International Journal of Hydrogen Energy, 2013)
Syngas has shown great success in Integrated Gasification Combined Cycle (IGCC) technology for providing cleaner and higher efficiency energy production with minimal environment impact. Thus, it is promising that Syngas is able to replace the conventional fossil fuel resources, while at the same time minimizing pollutants. The drawback of traditional Gas Turbines that burn Syngas is that they use diffusion flame combustion technology that suffers from low efficiency and high emissions. Recently, Lean premixed combustion technique has emerged as a promising solution, but the variation of hydrogen fraction in Syngas has prohibited its usage. Besides, other gases such as CO2, N2, H2O, NH3, and CH4 in Syngas have adverse effects on the combustion characteristics. To address these issues, better understanding of the Syngas's fundamental combustion properties are vital. Hence, recent works published on Syngas combustion at lean-premixed and Gas Turbine relevant conditions are reviewed, classified according to their objectives, and remarks were concluded. © 2013 Hydrogen Energy Publications, LLC.

Characterization of CpdC, a large-ring lactone-hydrolyzing enzyme from Pseudomonas sp. strain HI-70, and its use as a fusion tag facilitating overproduction of proteins in Escherichia coli - Xu, Y.; Grosse, S.; Iwaki, H.; Hasegawa, Y.; Lau, P.C.K. (Applied and Environmental Microbiology, 2013)
There are few entries of carbon-carbon bond hydrolases (EC 3.7.1.-) in the ExPASy database. In microbes, these enzymes play an essential role in the metabolism of alicyclic or aromatic compounds as part of the global carbon cycle. CpdC is aω-pentadecalactone hydrolase derived from the degradation pathway of cyclopentadecanol or cyclopentadecanone by Pseudomonas sp. strain HI-70. CpdC was purified to homogeneity and characterized. It is active as a dimer of 56,000 Da with a subunit molecular mass of 33,349. Although CpdC has the highest activity and reaction rate (kcat) towardω-pentadecalactone, its catalytic efficiency favors lauryl lactone as a substrate. The melting temperature (Tm) of CpdC was estimated to be 50.9±0.1°C. The half-life of CpdC at 35°C is several days. By virtue of its high level of expression in Escherichia coli, the intact CpdC-encoding gene and progressive 3=-end deletions were employed in the construction of a series of fusion plasmid system. Although we found them in inclusion bodies, proof-of-concept of overproduction of three microbial cutinases of which the genes were otherwise expressed poorly or not at all in E. coli was demonstrated. On the other hand, two antigenic proteins, azurin and MPT63, were readily produced in soluble form. © 2013, American Society for Microbiology.
Keywords: Carbon-carbon bond; Catalytic efficiencies; Degradation pathways; Expression in Escherichia coli; Global carbon cycle; Inclusion bodies; Pentadecalactone; Proof of concept; Bacteria; Dimers; Esters; Hydrolases; Proteins; Escherichia coli; bacterium; carbon cycle; coliform bacterium; enzyme activity; gene expression; homogeneity; hydrolysis; molecular analysis; plasmid; protein; solubilization

Force spectroscopy measurements show that cortical neurons exposed to excitotoxic agonists stiffen before showing evidence of bleb damage - Zou, S.; Chisholm, R.; Tauskela, J.S.; Mealing, G.A.; Johnston, L.J.; Morris, C.E. (PLoS ONE, 2013)
In ischemic and traumatic brain injury, hyperactivated glutamate (N-methyl-D-aspartic acid, NMDA) and sodium (Nav) channels trigger excitotoxic neuron death. Na+, Ca++ and H2O influx into affected neurons elicits swelling (increased cell volume) and pathological blebbing (disassociation of the plasma membrane's bilayer from its spectrin-actomyosin matrix). Though usually conflated in injured tissue, cell swelling and blebbing are distinct processes. Around an injury core, salvageable neurons could be mildly swollen without yet having suffered the bleb-type membrane damage that, by rendering channels leaky and pumps dysfunctional, exacerbates the excitotoxic positive feedback spiral. Recognizing when neuronal inflation signifies non-lethal osmotic swelling versus blebbing should further efforts to salvage injury-penumbra neurons. To assess whether the mechanical properties of osmotically-swollen versus excitotoxically-blebbing neurons might be cytomechanically distinguishable, we measured cortical neuron elasticity (gauged via atomic force microscopy (AFM)-based force spectroscopy) upon brief exposure to hypotonicity or to excitotoxic agonists (glutamate and Nav channel activators, NMDA and veratridine). Though unperturbed by solution exchange per se, elasticity increased abruptly with hypotonicity, with NMDA and with veratridine. Neurons then invariably softened towards or below the pre-treatment level, sometimes starting before the washout. The initial channel-mediated stiffening bespeaks an abrupt elevation of hydrostatic pressure linked to NMDA or Nav channel-mediated ion/H2O fluxes, together with increased [Ca++]int-mediated submembrane actomyosin contractility. The subsequent softening to below-control levels is consistent with the onset of a lethal level of bleb damage. These findings indicate that dissection/identification of molecular events during the excitotoxic transition from stiff/swollen to soft/blebbing is warranted and should be feasible. © 2013 Zou et al.
Keywords: calcium ion; glutamic acid; hypotonic solution; myosin adenosine triphosphatase; n methyl dextro aspartic acid; sodium channel; sodium ion; spectrin; veratridine; water; actin myosin interaction; animal cell; animal experiment; animal model; animal tissue; article; atomic force microscopy based force spectroscopy; bilayer membrane; bleb damage; brain cell; brain injury; brain ischemia; calcium transport; cell damage; cell stiffening; cell swelling; cell volume; controlled study; elasticity; excitotoxicity; exposure; female; hydrostatic pressure; measurement; membrane damage; nerve cell necrosis; nonhuman; osmosis; positive feedback; rat; sodium transport; spectroscopy; traumatic brain injury; water transport

Atomic force microscopy studies of conductive nanostructures in solid polymer electrolytes - Hiesgen, R.; Helmly, S.; Morawietz, T.; Yuan, X.-Z.; Wang, H.; Friedrich, K.A. (Electrochimica Acta, 2013)
The conductivity of three different sulfonated polymer electrolyte membranes (PEM), two perfluorinated membranes, Nafion® and Aquivion®, and JST, a non-perfluorinated aromatic block copolymer, were compared using advanced material-sensitive and conductive atomic force microscopy (AFM). All of the membranes required activation by a current flow to reach significant conductivity for the AFM analysis, indicating the existence of a highly resistive surface skin layer. The two perfluorinated sulfonic acid membranes, a membrane with long side-chains (Nafion ®) and a membrane with short side-chains (Aquivion ®), exhibited similar properties. A lamellar surface structure, with polymer bundles or micelles in a parallel orientation, was also found for the Aquivion® membrane. AFM high-resolution current images, performed under a continuous current flow, were used to distinguish between the conducting network and the subsurface phase distribution at the membrane surface. The connected subnets of the JST membrane were approximately 100-200 nm in size, whereas those for the perfluorinated membrane surfaces were 200-300 nm in size. The conductive areas of the Aquivion® and JST membranes exhibited larger homogeneous conducting areas, corresponding to the smaller correlation lengths of ionic phase separation. Membrane cross sections were analyzed to elucidate the structure of the bulk ionic network of the Nafion ® membrane, before and after operation. The existence of extended water layers in the bulk, even before operation, was confirmed.© 2013 Elsevier Ltd. All rights reserved.

Biodiagnostics using oriented and aligned inorganic semiconductor nanotubes and nanowires - Kar, P.; Shankar, K. (Journal of Nanoscience and Nanotechnology, 2013)
The simplicity of synthesis of deterministically positioned inorganic semiconductor nanorods (NRs) and nanotubes (NTs) coupled with their chemical stability, high surface area, controllable optical properties and tunable surface functionality, have sparked worldwide research efforts towards biodiagnostic applications. Biosensors based on oriented and aligned one-dimensional (1-D) inorganic semiconductor nanostructures have demonstrated remarkable detection sensitivity, high throughput and label-free operability. In comparison to suspensions of nanoparticles and discrete randomly oriented nanowires, nanowire (NW) and nanotube arrays offer continuous charge transport pathways, a major advantage for all-electrical detection and in exploiting electrokinetic effects. We review highly sensitive biosensors based on oriented and aligned NTs/NRs/NWs employing conventional detection methods, inclusive of fluorescence, electrochemistry and electromechanical sensing as well as detection methods unique to nanowires such as field-effect transistors. Entirely new types of sensing applications such as the impaling of living cells to monitor cellular events in situ, and substrates with electrically controlled wetting for surface-assisted laser desorption and ionization are emerging to take advantage of the unique properties of nanowire arrays. Concurrently, we explain the semiconductor materials and architectures employed, and the functionalization procedures used to construct the biosensors. Aligned semiconductor array-based approaches are critically examined in relation to prevailing technologies to get a sense of the exclusive niches that nanotube/nanorod array biosensors inhabit. The versatility of the detection principles that nanowire/nanotube arrays are compatible with are enabling hybrid approaches where combinations of detection methods are used. Such advantages offset the complexity associated with changing the status quo with respect to the current state-of-the-art in biodiagnostic platforms and devices. Copyright © 2013 American Scientific Publishers All rights reserved.
Keywords: Arrays; Biodiagnostics; Electrical measurement; ELectrochemical methods; Inorganic nanotubes; MALDI TOF MS; Nanomechanical; Optical interferometry; Cellular arrays; Electric properties; Electrochemistry; Field effect transistors; Fluorescence; Nanorods; Nanotubes; Nanowires; Biosensors; inorganic compound; nanotube; chemistry; conductometry; equipment; equipment design; equipment failure; genetic procedures; nanotechnology; review; semiconductor; Biosensing Techniques; Conductometry; Equipment Design; Equipment Failure Analysis; Inorganic Chemicals; Nanotechnology; Nanotubes; Semiconductors

Impact of human presence on secondary organic aerosols derived from ozone-initiated chemistry in a simulated office environment - Fadeyi, M.O.; Weschler, C.J.; Tham, K.W.; Wu, W.Y.; Sultan, Z.M. (Environmental Science and Technology, 2013)
Several studies have documented reductions in indoor ozone levels that occur as a consequence of its reactions with the exposed skin, hair and clothing of human occupants. One would anticipate that consumption of ozone via such reactions would impact co-occurring products derived from ozone's reactions with various indoor pollutants. The present study examines this possibility for secondary organic aerosols (SOA) derived from ozone-initiated chemistry with limonene, a commonly occurring indoor terpene. The experiments were conducted at realistic ozone and limonene concentrations in a 240 m3 chamber configured to simulate a typical open office environment. During an experiment the chamber was either unoccupied or occupied with 18-20 workers. Ozone and particle levels were continuously monitored using a UV photometric ozone analyzer and a fast mobility particle sizer (FMPS), respectively. Under otherwise identical conditions, when workers were present in the simulated office the ozone concentrations were approximately two-thirds and the SOA mass concentrations were approximately one-half of those measured when the office was unoccupied. This was observed whether new or used filters were present in the air handling system. These results illustrate the importance of accounting for occupancy when estimating human exposure to pollutants in various indoor settings. © 2013 American Chemical Society.
Keywords: Air handling systems; Fast mobility particle sizers; Identical conditions; Indoor pollutants; Mass concentration; Office environments; Ozone concentration; Secondary organic aerosols; Aerosols; Experiments; Monoterpenes; Ozone; limonene; ozone; terpene; aerosol; atmospheric pollution; concentration (composition); estimation method; experimental study; human activity; indoor air; ozone; simulation; ultraviolet radiation; adult; air pollution; article; chemical reaction; concentration (parameters); controlled study; environmental exposure; human; microclimate; photometry; pollutant; secondary organic aerosol; work environment

Comparative analysis of photocaged RGDS peptides for cell patterning - Goubko, C.A.; Basak, A.; Majumdar, S.; Jarrell, H.; Khieu, N.H.; Cao, X. (Journal of Biomedical Materials Research - Part A, 2013)
Photocaged RGDS is a cell nonadhesive tetrapeptide that can be activated with light to become cell-adhesive. Such molecules can find useful applications in controlling cell adhesion for biological study, drug development, and in forming dynamic, adhesion-controlled biomaterials. Herein, we prepared RGDS peptide photocaged either on the Arg-Gly backbone amide nitrogen atom (R[-]GDS) or Asp side chain carboxyl (RG[D]S). A critical comparison of the peptides' chemical and physiological properties relevant for biological applications was carried out. It was observed that RG[D]S was synthesized more readily via automated solid-phase synthesis, underwent uncaging with a rate constant 3-fold higher than R[-]GDS, and was more stable in aqueous solution. Automated docking studies were performed to examine the interactions of various caged RGDS peptides with cell surface integrin receptor to identify suitable locations for the photosensitive 2-nitrobenzyl (NB) group for biological applications. A competitive binding ELISA method compared the ability of various peptides to bind to αVβ3 cell integrin receptors and the data were found to be consistent with the modeling predictions. Finally, the application of our caged RGDS peptides in controlling cell adhesion to form cell patterns on a hydrogel material was presented. © 2012 Wiley Periodicals, Inc.
Keywords: 2-nitrobenzyl; Biological applications; Cell-patterning; Comparative analysis; Modeling predictions; Physiological properties; RGDS peptides; Solid phase synthesis; Biological materials; Cell adhesion; Cell membranes; Docking; Photochemical reactions; Rate constants; Peptides; alpha v beta 3 integrin receptor; arginylglycylaspartylserine; benzyl derivative; integrin receptor; unclassified drug; article; cell adhesion; cell patterning; cellular parameters; controlled study; enzyme linked immunosorbent assay; hydrogel; molecular docking; molecular interaction; molecular model; molecular stability; photolysis; photosensitivity; physiology; protein binding; protein function; protein synthesis; solid; Animals; Cell Adhesion; Coated Materials, Biocompatible; Humans; Integrin alphaVbeta3; Molecular Docking Simulation; Oligopeptides; Photochemical Processes; Protein Binding

Influence of the reaction stoichiometry on the mechanical and thermal properties of SWCNT-modified epoxy composites - Ashrafi, B.; Martinez-Rubi, Y.; Khoun, L.; Yourdkhani, M.; Kingston, C.T.; Hubert, P.; Simard, B.; Johnston, A. (Nanotechnology, 2013)
Previous studies suggest that carbon nanotubes (CNTs) have a considerable influence on the curing behavior and crosslink density of epoxy resins. This invariably has an important effect on different thermal and mechanical properties of the epoxy network. This work focuses on the important role of the epoxy/hardener mixing ratio on the mechanical and thermal properties of a high temperature aerospace-grade epoxy (MY0510 Araldite as an epoxy and 4,4′-diaminodiphenylsulfone as an aromatic hardener) modified with single-walled carbon nanotubes (SWCNTs). The effects of three different stoichiometries (stoichiometric and off-stoichiometric) on various mechanical and thermal properties (fracture toughness, tensile properties, glass transition temperature) of the epoxy resin and its SWCNT-modified composites were obtained. The results were also supported by Raman spectroscopy and scanning electron microscopy (SEM). For the neat resin, it was found that an epoxy/hardener molar ratio of 1:0.8 provides the best overall properties. In contrast, the pattern in property changes with the reaction stoichiometry was considerably different for composites reinforced with unfunctionalized SWCNTs and reduced SWCNTs. A comparison among composites suggests that a 1:1 molar ratio considerably outperforms the other two ratios examined in this work (1:0.8 and 1:1.1). This composition at 0.2 wt% SWCNT loading provides the highest overall mechanical properties by improving fracture toughness, ultimate tensile strength and ultimate tensile strain of the epoxy resin by 40%, 34%, 54%, respectively. © 2013 IOP Publishing Ltd.
Keywords: Cross-link densities; Diaminodiphenylsulfone; Mechanical and thermal properties; Overall properties; Reaction stoichiometry; Single-walled carbon nanotube (SWCNTs); Thermal and mechanical properties; Ultimate tensile strength; Curing; Epoxy resins; Fracture toughness; Mechanical properties; Raman spectroscopy; Resins; Scanning electron microscopy; Single-walled carbon nanotubes (SWCN); Tensile strength; Thermodynamic properties; Stoichiometry

Components of the cultivated red seaweed Chondrus crispus enhance the immune response of Caenorhabditis elegans to Pseudomonas aeruginosa through the pmk-1, daf-2/daf-16, and skn-1 pathways - Liu, Jianghua; Hafting, Jeff; Critchley, Alan T.; Banskota, Arjun H.; Prithiviraj, Balakrishnan (Applied and Environmental Microbiology, 2013)
Marine macroalgae are rich in bioactive compounds that can, when consumed, impart beneficial effects on animal and human health. The red seaweed Chondrus crispus has been reported to have a wide range of health-promoting activities, such as antitumor and antiviral activities. Using a Caenorhabditis elegans infection model, we show that C. crispus water extract (CCWE) enhances host immunity and suppresses the expression of quorum sensing (QS) and the virulence factors of Pseudomonas aeruginosa (strain PA14). Supplementation of nematode growth medium with CCWE induced the expression of C. elegans innate immune genes, such as irg-1, irg-2, F49F1.6, hsf-1, K05D8.5, F56D6.2, C29F3.7, F28D1.3, F38A1.5 ZK6.7, lys-1, spp-1, and abf-1, by more than 2-fold, while T20G5.7 was not affected. Additionally, CCWE suppressed the expression of PA14 QS genes and virulence factors, although it did not affect the growth of the bacteria. These effects correlated with a 28% reduction in the PA14-inflicted killing of C. elegans. Kappa-carrageenan (K-CGN), a major component of CCWE, was shown to play an important role in the enhancement of host immunity. Using C. elegans mutants, we identified that pmk-1, daf-2/daf-16, and skn-1 are essential in the K-CGN-induced host immune response. In view of the conservation of innate immune pathways between C. elegans and humans, the results of this study suggest that water-soluble components of C. crispus may also play a health-promoting role in higher animals and humans.

Continuum variability of deeply embedded protostars as a probe of envelope structure - Johnstone, D.; Hendricks, B.; Herczeg, G.J.; Bruderer, S. (The Astrophysical Journal, 2013)
Stars may be assembled in large growth spurts; however the evidence for this hypothesis is circumstantial. Directly studying the accretion at the earliest phases of stellar growth is challenging because young stars are deeply embedded in optically thick envelopes, which have spectral energy distributions that peak in the far-IR, where observations are difficult. In this paper, we consider the feasibility of detecting accretion outbursts from these younger stars by investigating the timescales for how the protostellar envelope responds to changes in the emission properties of the central source. The envelope heats up in response to an outburst, brightening at all wavelengths and with the emission peak moving to shorter wavelengths. The timescale for this change depends on the time for dust grains to heat and re-emit photons and the time required for the energy to escape the inner, optically thick portion of the envelope. We find that the dust response time is much shorter than the photon propagation time and thus the timescale over which the emission varies is set by time delays imposed by geometry. These times are hours to days near the peak of the spectral energy distribution and weeks to months in the sub-mm. The ideal location to quickly detect continuum variability is therefore in the mid- to far-IR, near the peak of the spectral energy distribution, where the change in emission amplitude is largest. Searching for variability in sub-mm continuum emission is also feasible, though with a longer time separation and a weaker relationship between the amount of detected emission amplitude and change in central source luminosity. Such observations would constrain accretion histories of protostars and would help to trace the disk/envelope instabilities that lead to stellar growth. © 2013. The American Astronomical Society. All rights reserved.

Fabrication of titanium/fluorapatite composites and in vitro behavior in simulated body fluid - Ye, H.; Liu, X.Y.; Hong, H. (Journal of Materials Science and Technology, 2013)
Titanium/fluorapatite (Ti/FA) composites with various FA additions were fabricated by powder metallurgy. The decomposition of FA during sintering was accelerated by the presence of Ti. The main reaction products of FA and Ti were identified as CaO, Ti phosphides, and CaTiO3. The addition of FA significantly inhibited the densification of Ti. The in vitro bioactivity of the composites was evaluated in a simulated body fluid (SBF). After immersion into the SBF, all the Ti/FA composites induced nucleation and growth of bone-like carbonated apatite on the surface. Co-precipitation of CaCO3 and Mg(OH)2 was also detected on the surface of the composite with high FA addition at an early stage of immersion. Furthermore, the release of fluorine ions from the composite was confirmed, which could promote bone regeneration and retard the formation of caries in the biological environment. The in vitro behavior was attributed to multiple factors, including the surface conditions and the constituents of the composite. The results demonstrated that the Ti/FA composites were bioactive in nature even with a low FA addition and they could introduce the benefit of fluorine ions in the service. © 2013.
Keywords: Biological environments; Carbonated apatite; Fluorapatites; In-vitro; In-vitro bioactivity; Induced nucleation; Simulated body fluids; Surface conditions; Bioactivity; Calcium carbonate; Fluorine; Phosphorus compounds; Powder metallurgy; Titanium; Sintering

A general approach for robust integrated polarization rotators - Alonso-Ramos, C.; Halir, R.; Ortega-Moñux, A.; Cheben, P.; Vivien, L.; Molina-Fernández, I.; Marris-Morini, D.; Janz, S.; Xu, D.-X.; Schmid, J. (SPIE - International Society for Optical Engineering. Proceedings, 2013)
Integrated polarization rotators suffer from very high sensitivity to fabrication errors. A polarization rotator scheme that substantially increases fabrication tolerances is proposed. In the proposed scheme, two tunable polarization phase shifters are used to connect three rotator waveguide sections. By means of properly setting the polarization phase shifters, fabrication errors are compensated and perfect polarization rotation is achieved. Analytical conditions are shown that determine the maximum deviation that can be corrected with the proposed scheme. A design example is discussed, where the thermo-optic effect is used to provide the required tunable polarization phase shifting. Calculated 40dB extinction ratio is shown in presence of fabrication errors that would yield a 4dB extinction ratio in the conventional approach.
Keywords: Analytical conditions; Conventional approach; Fabrication tolerances; Polarization diversity; Polarization phase; Polarization rotation; Polarization rotator; Thermooptic effects; Errors; Fabrication; Integrated optics; Light extinction; Optical communication; Phase shift; Phase shifters; Polarization

Global and local mechanical properties of autogenously laser welded Ti-6Al-4V - Cao, X.; Kabir, A.S.H.; Wanjara, P.; Gholipour, J.; Birur, A.; Cuddy, J.; Medraj, M. (Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 2013)
Ti-6Al-4V sheets, 3.2-mm in thickness, were butt welded using a continuous wave 4 kW Nd:YAG laser welding system. The effect of two main process parameters, laser power and welding speed, on the joint integrity was characterized in terms of the joint geometry, defects, microstructure, hardness, and tensile properties. In particular, a digital image correlation technique was used to determine the local tensile properties of the welds. It was determined that a wide range of heat inputs can be used to fully penetrate the Ti-6Al-4V butt joints during laser welding. At high laser power levels, however, significant defects such as underfill and porosity, can occur and cause marked degradation in the joint integrity and performance. At low welding speeds, however, significant porosity occurs due to its growth and the potential collapse of instable keyholes. Intermediate to relatively high levels of heat input allow maximization of the joint integrity and performance by limiting the underfill and porosity defects. In considering the effect of the two main defects on the joint integrity, the underfill defect was found to be more damaging to the mechanical performance of the weldment than the porosity. Specifically, it was determined that the maximum tolerable underfill depth for Ti-6Al-4V is approximately 6 pct of the workpiece thickness, which is slightly stricter than the value of 7 pct specified in AWS D17.1 for fusion welding in aerospace applications. Hence, employing optimized laser process parameters allows the underfill depth to be maintained within the tolerable limit (6 pct), which in turn prevents degradation in both the weld strength and ductility. To this end, the ability to maintain weld ductility in Ti-6Al-4V by means of applying a high energy density laser welding process presents a significant advantage over conventional arc welding for the assembly of aerospace components. © 2013 The Minerals, Metals & Materials Society and ASM International.

Photonic fractional-order differentiator using an soi microring resonator with an MMI coupler - Shahoei, H.; Xu, D.-X.; Schmid, J.H.; Yao, J. (IEEE Photonics Technology Letters, 2013)
An optically tunable fractional order temporal differentiator implemented using a silicon-on-isolator microring resonator with a multimode interference (MMI) coupler is proposed and experimentally demonstrated. Through changing the input polarization state, the self coupling coefficient and the loss factor of the designed ring resonator with the MMI coupler are changed. Correspondingly, the coupling regime is changed. Through changing the coupling regime from over-coupled to under-coupled regime, the phase shift in the resonance wavelength is changed from <π to >π. This tunable phase shift is used to implement a tunable fractional order photonic differentiator with an order tunable from <1 to > 1. The proposed fractional order differentiator is demonstrated experimentally. A Gaussian pulse with a bandwidth of 45 GHz is temporally differentiated with a tunable order of 0.37, 0.67, 1, 1.2, and 1.3. © 1989-2012 IEEE.
Keywords: Fractional order; Fractional order differentiator; Input polarization; Microring resonator; Multimode interference couplers; Optical Differentiator; Resonance wavelengths; Silicon photonics; Integrated optics; Phase shift; Phase shifters; Photonics; Optical resonators

A common pathway for O-linked protein-glycosylation and synthesis of capsule in Acinetobacter baumannii - Lees-Miller, R.G.; Iwashkiw, J.A.; Scott, N.E.; Seper, A.; Vinogradov, E.; Schild, S.; Feldman, M.F. (Molecular Microbiology, 2013)
Multi-drug resistant strains of Acinetobacter baumannii are increasingly being isolated in hospitals worldwide. Among the virulence factors identified in this bacterium there is a general O-glycosylation system that appears to be important for biofilm formation and virulence, and the capsular polysaccharide, which is essential for resistance to complement killing. In this work, we identified a locus that is responsible for the synthesis of the O-pentasaccharide found on the glycoproteins. Besides the enzymes required for the assembly of the glycan, additional proteins typically involved in polymerization and transport of capsule were identified within or adjacently to the locus. Mutagenesis of PglC, the initiating glycosyltransferase prevented the synthesis of both glycoproteins and capsule, resulting in abnormal biofilm structures and attenuated virulence in mice. These results, together with the structural analysis of A. baumannii 17978 capsular polysaccharide via NMR, demonstrated that the pentasaccharides that decorate the glycoproteins are also the building blocks for capsule biosynthesis. Two linked subunits, but not longer glycan chains, were detected on proteins via MS. The discovery of a bifurcated pathway for O-glycosylation and capsule synthesis not only provides insight into the biology of A. baumannii but also identifies potential novel candidates for intervention against this emerging pathogen. © 2013 John Wiley & Sons Ltd.
Keywords: glycoprotein; glycosyltransferase; pentasaccharide; Acinetobacter baumannii; article; bacterial capsule; bacterial virulence; biosynthesis; capsule biosynthesis; gene locus; glycoprotein synthesis; mass spectrometry; microbial attenuation; mouse; mutagenesis; nonhuman; nuclear magnetic resonance; priority journal; protein analysis; protein assembly; protein glycosylation; protein polymerization; protein structure; protein transport; reversed phase liquid chromatography; Acinetobacter baumannii; Bacteria (microorganisms); Mus

Susceptibility-weighted imaging in the experimental autoimmune encephalomyelitis model of multiple sclerosis indicates elevated deoxyhemoglobin, iron deposition and demyelination - Nathoo, N.; Agrawal, S.; Wu, Y.; Haylock-Jacobs, S.; Yong, V.W.; Foniok, T.; Barnes, S.; Obenaus, A.; Dunn, J.F. (Multiple Sclerosis, 2013)
Background: Susceptibility-weighted imaging (SWI) is an iron-sensitive magnetic resonance imaging (MRI) method that has shown iron-related lesions in multiple sclerosis (MS) patients. The contribution of deoxyhemoglobin to the signals seen in SWI has not been well characterized in MS. Objectives: To determine if SWI lesions (seen as focal hypointensities) exist in the experimental autoimmune encephalomyelitis (EAE) animal model of MS, and to determine whether the lesions relate to iron deposits, inflammation, demyelination, and/or deoxyhemoglobin in the vasculature. Methods: We performed SWI on the lumbar spinal cord and cerebellum of EAE and control mice (both complete Freund's adjuvant/pertussis toxin (CFA/PTX)-immunized and naive). We also performed SWI on mice before and after perfusion (to remove blood from vessels). SWI lesions were counted and their locations were compared to histology for iron, myelin and inflammation. Results: SWI lesions were found to exist in the EAE model. Many lesions seen by SWI were not present after perfusion, especially at the grey/white matter boundary of the lumbar spinal cord and in the cerebellum, indicating that these lesion signals were associated with deoxyhemoglobin present in the lumen of vessels. We also observed SWI lesions in the white matter of the lumbar spinal cord that corresponded to iron deposition, inflammation and demyelination. In the cerebellum, SWI lesions were present in white matter tracts, where we found histological evidence of inflammatory perivascular cuffs. Conclusions: SWI lesions exist in EAE mice. Many lesions seen in SWI were a result of deoxyhemoglobin in the blood, and so may indicate areas of hypoxia. A smaller number of SWI lesions coincided with parenchymal iron, demyelination, and/or inflammation. © The Author(s) 2012.
Keywords: deoxyhemoglobin; iron; myelin; allergic encephalomyelitis; animal experiment; animal model; animal tissue; article; cerebellum; controlled study; demyelination; disease model; female; gray matter; inflammation; lumbar spinal cord; mouse; multiple sclerosis; nonhuman; signal processing; susceptibility weighted imaging; white matter

Molecular strong field ionization and high harmonic generation: A selection of computational illustrations - Spanner, M.; Patchkovskii, S. (Chemical Physics, 2013)
Strong field ionization (SFI) and high harmonic generation (HHG) are the central processes that enable attosecond physics. To date, most theoretical investigations of SFI and HHG rely on semiclassical methods, most notably the strong field approximation (SFA), which treats the continuum states of the liberated electron as plane waves. SFA is a very successful conceptual model for atoms and small molecules, and leads to an intuitively satisfying picture of HHG (i.e. the three-step model). However, as SFI and HHG experiments enter the regime of polyatomic molecules, many approximations made in SFA-type models can no longer be ignored even for a qualitatively correct understanding. In this contribution, we present a selection of results from our efforts toward ab initio modeling of strong field processes in molecular systems. The method is applicable to single-electron ionization and HHG of gas-phase polyatomic molecular targets. © 2012 Elsevier B.V. All rights reserved.

Gene function hypotheses for the Campylobacter jejuni glycome generated by a logic-based approach - Sternberg, M.J.E.; Tamaddoni-Nezhad, A.; Lesk, V.I.; Kay, E.; Hitchen, P.G.; Cootes, A.; Van Alphen, L.B.; Lamoureux, M.P.; Jarrell, H.C.; Rawlings, C.J.; Soo, E.C.; Szymanski, C.M.; et al. (Journal of Molecular Biology, 2013)
Increasingly, experimental data on biological systems are obtained from several sources and computational approaches are required to integrate this information and derive models for the function of the system. Here, we demonstrate the power of a logic-based machine learning approach to propose hypotheses for gene function integrating information from two diverse experimental approaches. Specifically, we use inductive logic programming that automatically proposes hypotheses explaining the empirical data with respect to logically encoded background knowledge. We study the capsular polysaccharide biosynthetic pathway of the major human gastrointestinal pathogen Campylobacter jejuni. We consider several key steps in the formation of capsular polysaccharide consisting of 15 genes of which 8 have assigned function, and we explore the extent to which functions can be hypothesised for the remaining 7. Two sources of experimental data provide the information for learning - the results of knockout experiments on the genes involved in capsule formation and the absence/presence of capsule genes in a multitude of strains of different serotypes. The machine learning uses the pathway structure as background knowledge. We propose assignments of specific genes to five previously unassigned reaction steps. For four of these steps, there was an unambiguous optimal assignment of gene to reaction, and to the fifth, there were three candidate genes. Several of these assignments were consistent with additional experimental results. We therefore show that the logic-based methodology provides a robust strategy to integrate results from different experimental approaches and propose hypotheses for the behaviour of a biological system. © 2012 Elsevier Ltd.
Keywords: glucuronosyltransferase; heptose guanosyltransferase; heptose kinase; methyltransferase; sedoheptulose isomerase; sugar transferase; unclassified drug; article; Campylobacter jejuni; DNA microarray; gene expression; gene function; knockout gene; machine learning; nonhuman; priority journal; serotype; Artificial Intelligence; Bacterial Capsules; Biosynthetic Pathways; Campylobacter jejuni; Gene Knockout Techniques; Genes, Bacterial; Glycomics; Logic; Metabolomics; Models, Biological; Molecular Sequence Annotation; Mutation; Oligonucleotide Array Sequence Analysis; Phenotype; Polysaccharides, Bacterial; Systems Biology; Campylobacter jejuni

Potential shortfall of pyramided transgenic cotton for insect resistance management - Brévault, T.; Heuberger, S.; Zhang, M.; Ellers-Kirk, C.; Ni, X.; Masson, L.; Li, X.; Tabashnik, B.E.; Carrière, Y. (Proceedings of the National Academy of Sciences of the United States of America, 2013)
To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. In the United States, this strategy has been adopted widely, with two-toxin Bt cotton replacing one-toxin Bt cotton. Although two-toxin plants are likely to be more durable than one-toxin plants, the extent of this advantage depends on several conditions. One key assumption favoring success of two-toxin plants is that they kill insects selected for resistance to one toxin, which is called "redundant killing." Here we tested this assumption for a major pest, Helicoverpa zea, on transgenic cotton producing Bt toxins Cry1Ac and Cry2Ab. Selection with Cry1Ac increased survival on two-toxin cotton, which contradicts the assumption. The concentration of Cry1Ac and Cry2Ab declined during the growing season, which would tend toexacerbate this problem. Furthermore, analysis of results from 21 selection experiments with eight species of lepi-dopteran pests indicates that some cross-resistance typically occurs between Cry1A and Cry2A toxins. Incorporation of empirical data into simulation models shows that the observed deviations from ideal conditions could greatly reduce the benefits of the pyramid strategy for pests like H. zea, which have inherently low susceptibility to Bt toxins and have been exposed extensively to one of the toxins in the pyramid before two-toxin plants are adopted. For such pests, the pyramid strategy could be improved by incorporating empirical data on deviations from ideal assumptions about redundant killing and cross-resistance.
Keywords: Cry1Ab toxin; Cry1Ac toxin; article; controlled study; cotton; cross resistance; Diatracea saccharalis; Helicoverpa armigera; Helicoverpa punctigera; Helicoverpa zea; heliothis virescens; insect resistance; Lepidoptera; nonhuman; Pectinophora gossypiella; plant growth; plant leaf; Plutella xylostella; priority journal; seasonal variation; simulation; species; survival; transgenic plant; trichoplusia ni; Alleles; Animals; Bacillus thuringiensis; Bacterial Proteins; Crops, Agricultural; Endotoxins; Gossypium; Hemolysin Proteins; Inhibitory Concentration 50; Insecticide Resistance; Insecticides; Moths; Pest Control, Biological; Plants, Genetically Modified; Bacillus thuringiensis; Gossypium hirsutum; Helicoverpa zea; Hexapoda

Understanding chair absorption characteristics using the perimeter-to-area method - Bradley, J.S.; Choi, Y.-J.; Jeong, D.-U. (Applied Acoustics, 2013)
Measurements of the sound absorption of several blocks of chairs with varied perimeter-to-area (P/A) ratios were used to examine how chair absorption coefficients are related to their physical characteristics. Because the P/A method combines the results of several samples of each type of chair, a more accurate understanding can be obtained of how the physical properties of the chairs are related to their sound absorption characteristics. Unoccupied chairs are shown to have a wide range of characteristics and it is necessary to test each type of chair to accurately predict their effect in an auditorium. However, the absorption characteristics of occupied chairs are strongly influenced by the absorption of the occupants and an approximate average sound absorption characteristic can be useful for predicting the effect of occupied chairs in an auditorium. Although the variations of sound absorption with row spacing are related to P/A, the variations are quite different than when simply changing the P/A for chair samples with constant row spacing. Both chair underpass height and chair back height affect the absorption characteristics of theater chairs, but the effects can be influenced by the presence of carpet under the chairs or by occupants in the chairs. Common sources of increased sound absorption in each octave band are identified and discussed. © 2013 Elsevier B.V.All rights reserved.
Keywords: Absorption characteristics; Absorption co-efficient; Common source; Measurements of; Perimeter-to-area; Physical characteristics; Sound absorption; Sound absorption characteristic; Auditoriums; Sound insulating materials; Acoustic wave absorption

Acute toxicities of saxitoxin, neosaxitoxin, decarbamoyl saxitoxin and gonyautoxins 1&4 and 2&3 to mice by various routes of administration - Munday, R.; Thomas, K.; Gibbs, R.; Murphy, C.; Quilliam, M.A. (Toxicon, 2013)
Saxitoxin and its derivatives, the paralytic shellfish toxins (PSTs), are known to be toxic to humans, and maximum permitted levels in seafood have been established by regulatory authorities in many countries. Until recently, the mouse bioassay was the reference method for determining the levels of these toxins in seafood, but this has now been superseded by chemical methods of analysis. The latter methods are able to determine the levels of many PSTs in shellfish, but for risk assessment an estimate of the relative toxicities of the individual components of the PST mixture is required. The relative toxicities are expressed as "Toxicity Equivalence Factors" (TEFs). At present, TEFs are based on relative specific activities in the mouse bioassay, rather than on acute toxicity determinations, as measured by median lethal doses (LD50s). In the present study, the median lethal doses of saxitoxin, neosaxitoxin, decarbamoyl saxitoxin and equilibrium mixtures of gonyautoxins 1&4 and gonyautoxins 2&3 have been determined by intraperitoneal injection, gavage and feeding. The results indicate that specific activities in the MBA do not consistently correlate with acute toxicities by any of the routes of administration, and TEFs, particularly for neosaxitoxin, require revision. © 2013 Elsevier Ltd.
Keywords: decarbamoylsaxitoxin; gonyautoxin; neosaxitoxin; saxitoxin; acute toxicity; animal experiment; article; calibration; female; LD 50; mortality; mouse; nonhuman; priority journal; toxicity equivalence factor; toxicological parameters

Relationship between soot volume fraction and LII signal in AC-LII: effect of primary soot particle diameter polydispersity - Liu, F.; Smallwood, G.J. (Applied Physics B: Lasers and Optics, 2013)
Theoretical analysis and numerical calculations were conducted to investigate the relationship between soot volume fraction and laser-induced incandescence (LII) signal within the context of the auto-compensating LII technique. The emphasis of this study lies in the effect of primary soot particle diameter polydispersity. The LII model was solved for a wide range of primary soot particle diameters from 2 to 80 nm. For a log-normally distributed soot particle ensemble encountered in a typical laminar diffusion flame at atmospheric pressure, the LII signals at 400 and 780 nm were calculated. To quantify the effects of sublimation and differential conduction cooling on the determined soot volume fraction in auto-compensating LII, two new quantities were introduced and demonstrated to be useful in LII study: an emission intensity distribution function and a scaled soot volume fraction. When the laser fluence is sufficiently low to avoid soot mass loss due to sublimation, accurate soot volume fraction can be obtained as long as the LII signals are detected within the first 200 ns after the onset of the laser pulse. When the laser fluence is in the high fluence regime to induce significant sublimation, however, the LII signals should be detected as early as possible even before the laser pulse reaches its peak when the laser fluence is sufficiently high. The analysis method is shown to be useful to provide guidance for soot volume fraction measurements using the auto-compensating LII technique. © 2013 Her Majesty the Queen in Right of Canada.

UV-induced atomization of gaseous mercury hydrides for atomic fluorescence spectrometric detection of inorganic and organic mercury after high performance liquid chromatographic separation - Huang, K.; Xu, K.; Hou, X.; Jia, Y.; Zheng, C.; Yang, L. (Journal of Analytical Atomic Spectrometry, 2013)
A novel, simple, low power, low temperature (<45 °C) and high efficiency atomization technique using ultraviolet (UV) radiation was proposed for the atomization of gaseous mercury hydrides for their determination by atomic fluorescence spectrometry (AFS). This technique was used for the detection of inorganic mercury (Hg2+) and organic mercury (MeHg + and EtHg+) after high performance liquid chromatographic separation. In the proposed method, with 0.5% (m/v) KBH4 used as a reductant, inorganic mercury was reduced to elemental mercury, whereas the organic mercury species formed their respective volatile organic mercury hydrides (MeHgH and EtHgH) which were flushed to the UV atomizer for atomization and AFS detection. Under the optimized experimental conditions, the limits of detection were found to be 0.38, 0.41 and 0.56 μg L-1, and the relative standard deviations (n = 3) were 1.1%, 2.6% and 1.4% for Hg 2+, MeHg+ and EtHg+, respectively. The accuracy of the proposed method was validated by analyzing a certified reference sample (fish muscle tissue) with a satisfactory analytical result, and two water samples with recoveries in the range of 93.8-97.4%.© The Royal Society of Chemistry 2013.
Keywords: Analytical results; Atomic fluorescence; Atomic fluorescence spectrometry; Experimental conditions; Limits of detection; Liquid chromatographic separations; Relative standard deviations; Spectrometric detection; Atomization; Chromatography; Fluorescence spectroscopy; High performance liquid chromatography; Hydrides; Tissue; Mercury (metal)

The ACS Virgo cluster survey. XVII. The spatial alignment of globular cluster systems with early-type host galaxies - Wang, Q.; Peng, E.W.; Blakeslee, J.P.; Côté, P.; Ferrarese, L.; Jordán, A.; Mei, S.; West, M.J. (The Astrophysical Journal, 2013)
We study the azimuthal distribution of globular clusters (GCs) in early-type galaxies and compare them to their host galaxies using data from the ACS Virgo Cluster Survey. We find that in host galaxies with visible elongation (ε > 0.2) and intermediate to high luminosities (Mz < -19), the GCs are preferentially aligned along the major axis of the stellar light. The red (metal-rich) GC subpopulations show strong alignment with the major axis of the host galaxy, which supports the notion that these GCs are associated with metal-rich field stars. The metal-rich GCs in lenticular galaxies show signs of being more strongly associated with disks rather than bulges. Surprisingly, we also find that the blue (metal-poor) GCs can also show the same correlation. If the metal-poor GCs are part of the early formation of the halo and built up through mergers, then our results support a picture where halo formation and merging occur anisotropically, and that the present-day major axis is an indicator of the preferred merging axis. © 2013. The American Astronomical Society. All rights reserved..

A key role of microRNA-29b for the suppression of colon cancer cell migration by American ginseng - Poudyal, D.; Cui, X.; Le, P.M.; Hofseth, A.B.; Windust, A.; Nagarkatti, M.; Nagarkatti, P.S.; Schetter, A.J.; Harris, C.C.; Hofseth, L.J. (PLoS ONE, 2013)
Metastasis of colon cancer cells increases the risk of colon cancer mortality. We have recently shown that American ginseng prevents colon cancer, and a Hexane extract of American Ginseng (HAG) has particularly potent anti-inflammatory and anti-cancer properties. Dysregulated microRNA (miR) expression has been observed in several disease conditions including colon cancer. Using global miR expression profiling, we observed increased miR-29b in colon cancer cells following exposure to HAG. Since miR-29b plays a role in regulating the migration of cancer cells, we hypothesized that HAG induces miR-29b expression to target matrix metalloproteinase-2 (MMP-2) thereby suppressing the migration of colon cancer cells. Results are consistent with this hypothesis. Our study supports the understanding that targeting MMP-2 by miR-29b is a mechanism by which HAG suppresses the migration of colon cancer cells.
Keywords: gelatinase A; hexane; microRNA 29b; Panax quinquefolius extract; plant extract; unclassified drug; antineoplastic activity; article; cancer inhibition; cell migration; colon cancer; human; human cell; molecular mechanics; nonhuman; Panax quinquefolius; protein function; protein targeting; regulatory mechanism

Mesoporous carbons supported non-noble metal Fe-N X electrocatalysts for PEM fuel cell oxygen reduction reaction - Monteverde Videla, A.H.A.; Zhang, L.; Kim, J.; Zeng, J.; Francia, C.; Zhang, J.; Specchia, S. (Journal of Applied Electrochemistry, 2013)
Three types of iron-nitrogen-containing non-noble metal catalysts, supported on an ultrasonic spray pyrolysis mesoporous carbon (USPMC), a hollow core mesoporous shell carbon (HCMSC), and a standard carbon (Ketjen Black CJ600, KB), respectively, are synthesized using a wet-impregnation method. The morphologies and structure as well as composition of the synthesized carbon supports and their corresponding supported Fe-N X catalysts (namely Fe-N X /USPMC, Fe-N X /HCMSC, and Fe-N X /KB, respectively) are physically characterized using EDX, SEM, FESEM, and BET analysis, respectively. The catalytic activities of these three electrocatalysts toward oxygen reduction reaction (ORR) are measured using rotating disk electrode technique in O2-saturated 0.5 M H2SO4 solution. The catalyzed ORR exchange current densities are also obtained using the Tafel method based on the measured data. Among these three electrocatalysts, Fe-N X /HCMSC can give the best ORR performance, which is correlated to its higher nitrogen, mesopore, and micropore contents, compared to the other electrocatalysts. It is rationalized that the performance improvement of these electrocatalysts may be achieved as long as an optimal relationship among mesopores, micropores, and even macropores for increasing both ORR kinetics and reactant gases accessibility to the active sites can be found. © 2012 Springer Science+Business Media Dordrecht.
Keywords: Exchange current densities; Hollow core-mesoporous shell carbons; Mesoporosity; Mesoporous carbon; Non-noble metal catalysts; Oxygen reduction reaction; Performance improvements; Ultrasonic spray pyrolysis; Carbon; Electrolysis; Electrolytic reduction; Mesoporous materials; Microporosity; Nitrogen; Precious metals; Proton exchange membrane fuel cells (PEMFC); Rotating disks; Spray pyrolysis; Ultrasonic applications; Electrocatalysts

Prediction of the active layer nanomorphology in polymer solar cells using molecular dynamics simulation - Ashrafi Khajeh, A.R.; Shankar, K.; Choi, P. (ACS Applied Materials and Interfaces, 2013)
Active layer nanomorphology is a major factor that determines the efficiency of bulk heterojunction polymer solar cells (PSCs). Synthesizing diblock copolymers in which acceptor and donor materials are the constituent blocks is the most recent method to control the structure of the active layer. In the current work, a computational method is proposed to predict the nanomorphology of the active layer consisting of a diblock copolymer. Diblock copolymers have a tendency to self-organize and form well-defined nanostructures. The shape of the structure depends on the Flory-Huggins interaction parameter (i.e., χ), the total degree of polymerization (N) and volume fractions of the constituent blocks (φi). In this work, molecular dynamics (MD) simulations were used to calculate χ parameters for two different block copolymers used in PSCs: P3HT-b-poly(S8A 2)-C60 and P3HT-b-poly(n-butyl acrylate-stat-acrylate perylene) also known as P3HT-b-PPerAcr. Such calculations indicated strong segregation of blocks into cylindrical structure for P3HT-b-poly(S 8A2)-C60 and intermediate segregation into cylindrical structure for P3HT-b-PPerAcr. Experimental results of P3HT-b-poly(S8A2)-C60 and P3HT-b-PTP4AP, a diblock copolymer having very similar structure to P3HT-b-PPerAcr, validate our predictions. © 2013 American Chemical Society.
Keywords: Active Layer; Bulk heterojunction; Cylindrical structure; Degree of polymerization; Flory-Huggins interaction parameter; Molecular dynamics simulations; Nanomorphologies; Polymer solar cell (PSCs); Heterojunctions; Molecular dynamics; Molecular mechanics; Nanostructured materials; Solar cells; Block copolymers

Coiled-coil-mediated grafting of bioactive vascular endothelial growth factor - Murschel, F.; Liberelle, B.; St-Laurent, G.; Jolicoeur, M.; Durocher, Y.; De Crescenzo, G. (Acta Biomaterialia, 2013)
Chimeric growth factors may represent a powerful alternative to their natural counterparts for the functionalization of tissue-engineered scaffolds and applications in regenerative medicine. Their rational design should provide a simple, readily scalable production strategy while improving retention at the site of action. In that endeavor, we here report the synthesis of a chimeric protein corresponding to human vascular endothelial growth factor 165 being N-terminally fused to an E5 peptide tag (E5-VEGF). E5-VEGF was successfully expressed as a homodimer in mammalian cells. Following affinity purification, in vitro surface plasmon resonance biosensing and cell survival assays confirmed diffusible E5-VEGF ability to bind to its receptor ectodomains, while observed morphological phenotypes confirmed its anti-apoptotic features. Additional surface plasmon resonance assays highlighted that E5-VEGF could be specifically captured with high stability when interacting with covalently immobilized K5 peptide (a synthetic peptide designed to bind to the E5 moiety of chimeric hVEGF). This immobilization strategy was applied to glass substrates and chimeric hVEGF was shown to be maintained in a functionally active state following capture. Altogether, our data demonstrated that stable hVEGF capture can be performed via coiled-coil interactions without impacting hVEGF bioactivity, thus opening up the way to future applications in the field of tissue engineering and regenerative medicine. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Keywords: chimeric protein; homodimer; vasculotropin; vasculotropin 165; article; assay; biological activity; cell survival; controlled study; human; human cell; immobilization; in vitro study; phenotype; priority journal; protein binding; surface plasmon resonance; Mammalia

Advanced oxidation using Fe₃O₄ magnetic nanoparticles and its application in mercury speciation analysis by high performance liquid chromatography-cold vapor generation atomic fluorescence spectrometry - Ai, Xi; Wang, Yu; Hou, Xiandeng; Yang, Lu; Zheng, Chengbin; Wu, Li (Analyst, 2013)
A novel, green and efficient post-column oxidation method using Fe₃O₄4 magnetic nanoparticles (MNPs) was developed to on-line convert hydride generation/cold vapor generation (HG/CV) inactive species to their active species without microwave/UV irradiation. It was applied to high performance liquid chromatography HG/CV atomic fluorescence spectrometry (HPLC-HG/CV-AFS) to enable sensitive speciation analysis of both HG/CV inactive and active species. Inorganic mercury (Hg²⁺), methylmercury (MeHg), ethylmercury (EtHg) and phenylmercury (PhHg) were selected as model compounds to validate the methodology. Separation of these mercury species was accomplished on a RP-C18 column with a mixture of acetonitrile and water (10 : 90) at pH 6.8 containing 0.12% (m/v) l-cysteine as the mobile phase. In the presence of 0.6% (v/v) H₂O₂, on-line conversion of the organomercury species eluted from the HPLC column to Hg²⁺ was obtained using the advanced oxidation method at pH 2.0. Optimum conditions for the separation, oxidation and cold vapor generation were carefully investigated. The limits of detection (LODs) were 0.7, 1.1, 0.8 and 0.9 μg L-1 (as Hg) for Hg²⁺, MeHg, EtHg and PhHg, respectively, corresponding to 14, 22, 16 and 18 pg absolute detection limits for Hg²⁺, MeHg, EtHg and PhHg by using a 20 μL sample loop, which are comparable to or better than those previously reported. National Research Council Canada DORM-2 fish muscle tissue and several real water samples were analyzed to validate the accuracy of the proposed method.

Resolving multiple non-equivalent metal sites in magnesium-containing metal-organic frameworks by natural abundance 25Mg solid-state NMR spectroscopy - Xu, J.; Terskikh, V.V.; Huang, Y. (Chemistry - A European Journal, 2013)
In a spin: Directly differentiating multiple Mg sites in Mg-containing MOFs by 25Mg solid-state NMR spectroscopy is very challenging at natural abundance. By performing 25Mg two-dimensional triple-quantum magic-angle spinning solid-state NMR experiments at a magnetic field of 21.1 T at natural abundance, four non-equivalent Mg sites with very similar local environments in α-Mg3(HCOO)6 were unambiguously resolved (see figure). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Keywords: 3QMAS; Local environments; Metal organic framework; Metal sites; Natural abundance; Solid state NMR; Solid-state NMR spectroscopy; Theoretical calculations; Crystalline materials; Magic angle spinning; Microporous materials; Solid state physics; Nuclear magnetic resonance spectroscopy

Quantification of superparamagnetic iron oxide using inversion recovery balanced steady-state free precession - Pelot, N.A.; Bowen, C.V. (Magnetic Resonance Imaging, 2013)
Cellular and molecular MRI trafficking studies using superparamagnetic iron oxide (SPIO) have greatly improved non-invasive investigations of disease progression and drug efficacy, but thus far, these studies have largely been restricted to qualitative assessment of hypo- or hyperintense areas near SPIO. In this work, SPIO quantification using inversion recovery balanced steady-state free precession (IR-bSSFP) was demonstrated at 3T by extracting R2 values from a monoexponential model (P. Schmitt et al., 2004). A low flip angle was shown to reduce the apparent recovery rate of the IR-bSSFP time course, thus extending the dynamic range of quantification. However, low flip angle acquisitions preclude the use of traditional methods for combining RF phase-cycled images to reduce banding artifacts arising from off-resonance due to B0 inhomogeneity. To achieve R2 quantification of SPIO, we present a new algorithm applicable to low flip angle IR-bSSFP acquisitions that is specifically designed to identify on-resonance acquisitions. We demonstrate in this work, using both theoretical and empirical methods, that the smallest estimated R2 from multiple RF phase-cycled acquisitions correspond well to the on-resonance time course. Using this novel minimum R2 algorithm, homogeneous R2 maps and linear R2 calibration curves were created up to 100μg(Fe)/mL with 20° flip angles, despite substantial B0 inhomogeneity. In addition, we have shown this technique to be feasible for pre-clinical research: the minimum R2 algorithm was resistant to off-resonance in a single slice mouse R2 map, whereas maximum intensity projection resulted in banding artifacts and overestimated R2 values. With the application of recent advances in accelerated acquisitions, IR-bSSFP has the potential to quantify SPIO in vivo, thus providing important information for oncology, immunology, and regenerative medicine MRI studies. © 2013.
Keywords: superparamagnetic iron oxide; algorithm; animal experiment; article; artifact; calibration; feasibility study; in vitro study; in vivo study; inversion recovery balanced steady state free precession; mathematical model; mouse; nonhuman; nuclear magnetic resonance imaging; priority journal; quantitative analysis; simulation

Lap shear strength and fatigue behavior of friction stir spot welded dissimilar magnesium-to-aluminum joints with adhesive - Chowdhury, S.H.; Chen, D.L.; Bhole, S.D.; Cao, X.; Wanjara, P. (Materials Science and Engineering A, 2013)
Lightweighting is currently considered as an effective way in improving fuel efficiency and reducing anthropogenic greenhouse gas emissions. The structural applications of lightweight magnesium and aluminum alloys in the aerospace and automotive sectors unavoidably involve welding and joining while guaranteeing the safety and durability of motor vehicles. The objective of this study was to evaluate the lap shear strength and fatigue properties of friction stir spot welded (FSSWed) dissimilar AZ31B-H24 Mg alloy and Al alloy (AA) 5754-O in three combinations, i.e., (top) Al/Mg (bottom), Al/Mg with an adhesive interlayer, and Mg/Al with an adhesive interlayer. For all the dissimilar Mg-to-Al weld combinations, FSSW induced an interfacial layer in the stir zone (SZ) that was composed of intermetallic compounds of Al3Mg2 and Al12Mg17, which led to an increase in hardness. Both Mg/Al and Al/Mg dissimilar adhesive welds had significantly higher lap shear strength, failure energy and fatigue life than the Al/Mg dissimilar weld without adhesive. Two different types of fatigue failure modes were observed. In the Al/Mg adhesive weld, at high cyclic loads nugget pull-out failure occurred due to fatigue crack propagation circumferentially around the nugget. At low cyclic loads, fatigue failure occurred in the bottom Mg sheet due to the stress concentration of the keyhole leading to crack initiation followed by propagation perpendicular to the loading direction. In the Mg/Al adhesive weld, nugget pull-out failure mode was primarily observed at both high and low cyclic loads. © 2012 Elsevier B.V.
Keywords: Adhesive interlayers; Al alloys; Anthropogenic greenhouse gas emissions; Automotive sector; Dissimilar weld; Failure energy; Fatigue behavior; Fatigue failure mode; Fatigue failures; Fatigue properties; Friction stir; Friction stir spot welding; Fuel efficiency; Interfacial layer; Lap shear strength; Lightweighting; Loading direction; Mg alloy; Motor vehicle; Pull-out failure; Spot welded; Stir zones; Structural applications; Adhesives; Aluminum; Cyclic loads; Failure modes; Fatigue of materials; Gas emissions; Greenhouse gases; Magnesium; Magnesium alloys; Spot welding; Stress concentration; Welding; Welds; Aluminum alloys

Reactions of the cumyloxyl and benzyloxyl radicals with tertiary amides. hydrogen abstraction selectivity and the role of specific substrate-radical hydrogen bonding - Salamone, M.; Milan, M.; Dilabio, G.A.; Bietti, M. (Journal of Organic Chemistry, 2013)
A time-resolved kinetic study in acetonitrile and a theoretical investigation of hydrogen abstraction reactions from N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) by the cumyloxyl (CumO•) and benzyloxyl (BnO•) radicals was carried out. CumO • reacts with both substrates by direct hydrogen abstraction. With DMF, abstraction occurs from the formyl and N-methyl C-H bonds, with the formyl being the preferred abstraction site, as indicated by the measured k H/kD ratios and by theory. With DMA, abstraction preferentially occurs from the N-methyl groups, whereas abstraction from the acetyl group represents a minor pathway, in line with the computed C-H BDEs and the kH/kD ratios. The reactions of BnO• with both substrates were best described by the rate-limiting formation of hydrogen-bonded prereaction complexes between the BnO• α-C-H and the amide oxygen, followed by intramolecular hydrogen abstraction. This mechanism is consistent with the very large increases in reactivity measured on going from CumO• to BnO• and with the observation of kH/kD ratios close to unity in the reactions of BnO•. Our modeling supports the different mechanisms proposed for the reactions of CumO• and BnO • and the importance of specific substrate/radical hydrogen bond interactions, moreover providing information on the hydrogen abstraction selectivity. © 2013 American Chemical Society.
Keywords: Hydrogen abstraction reaction; Hydrogen bond interaction; Intramolecular hydrogen; N ,N-Dimethylacetamide; N ,N-Dimethylformamide; Rate-limiting formation; Theoretical investigations; Time-resolved kinetic study; Amides; Functional groups; Hydrogen bonds; Organic solvents; Substrates; Abstracting; acetic acid derivative; aliphatic amine; amide; benzyloxyl radical; carbon; cumyloxyl radical; dimethyl sulfoxide; hydrogen; hydroxyl radical; n,n dimethylacetamide; n,n dimethylformamide; oxygen; tertiary amine; unclassified drug; article; calculation; chemical reaction kinetics; chemical structure; controlled study; density functional theory; dissociation constant; enzyme specificity; hydrogen bond; mathematical computing; molecular interaction; phase transition; stereochemistry

Magnesium and magnesium-silicide coated silicon nanowire composite anodes for lithium-ion batteries - Kohandehghan, A.; Kalisvaart, P.; Kupsta, M.; Zahiri, B.; Amirkhiz, B.S.; Li, Z.; Memarzadeh, E.L.; Bendersky, L.A.; Mitlin, D. (Journal of Materials Chemistry A, 2013)
We synthesized composites consisting of silicon nanowires (SiNWs) coated with magnesium (Mg) and magnesium silicide (Mg2Si) for lithium-ion battery anodes and studied their electrochemical cycling stability and degradation mechanisms. Compared to bare SiNWs, both Mg- and Mg 2Si-coated materials show significant improvement in coulombic efficiency during cycling, with pure Mg coating being slightly superior by ∼1% in each cycle. XPS measurements on cycled nanowire forests gave quantitative information on the composition of the SEI layer and showed lower Li2CO3 and higher polyethylene oxide content for coated nanowires, thus revealing a passivating effect towards electrolyte decomposition. Extensive characterization of the microstructure before and after cycling was carried out by scanning- and transmission electron microscopy aided by focused ion beam cross-sectioning. The formation of large voids between the nanowire assembly and the substrate during cycling, causing the nanowires to lose electrical contact with the substrate, is identified as an important degradation mechanism. © 2013 The Royal Society of Chemistry.
Keywords: Coulombic efficiency; Degradation mechanism; Electrical contacts; Electrochemical cycling stability; Electrolyte decomposition; Lithium-ion battery anodes; Magnesium silicides; Quantitative information; Anodes; Coated materials; Degradation; Lithium batteries; Magnesium; Polyethylene oxides; Silicides; Silicon; Transmission electron microscopy; Nanowires

Effect of surface hydrophilicity on the formation of Nafion thin films inside PEMFC catalyst layers: A computational study - Damasceno Borges, D.; Malek, K.; Mossa, S.; Gebel, G.; Franco, A.A. (ECS Transactions, 2013)
Structure of Nafion inside Polymer Electrolyte Membrane Fuel Cells (PEMFC) catalyst layers is suspected to have a significant impact on the electrochemical activity and transport phenomena that determine the overall cell performances. In those regions, Nafion can be found as an ultra-thin film, coating the catalyst and the catalyst support surfaces. The impact of the hydrophilic character of these surfaces on the structural formation of the films has not been explored in details yet. Here, we report about our Molecular Dynamic computer simulations studies of the formation of Nafion thin films in contact with unstructured continuous surfaces, characterized by their global wetting properties only. We investigate changes of morphology and nanostructure of the perfluorosulfonic acid polymer as a result of water and polymersurface affinities. Charge and water distributions are also analyzed. Possible impact of Nafion thin film self-assembly on the actual activity properties of realistic catalysts layers is shortly discussed. © The Electrochemical Society.
Keywords: Computational studies; Continuous surface; Electrochemical activities; Perfluorosulfonic acid; Structural formation; Surface hydrophilicity; Transport phenomena; Water distributions; Binders; Catalyst activity; Computer simulation; Hydrophilicity; Molecular dynamics; Polymers; Ultrathin films; Water supply systems; Proton exchange membrane fuel cells (PEMFC)

Radio continuum surveys with square kilometre array pathfinders - Norris, R.P.; Afonso, J.; Bacon, D.; Beck, R.; Bell, M.; Beswick, R.J.; Best, P.; Bhatnagar, S.; Bonafede, A.; Brunetti, G.; Budavári, T.; Cassano, R.; et al. (Publications of the Astronomical Society of Australia, 2013)
In the lead-up to the Square Kilometre Array (SKA) project, several next-generation radio telescopes and upgrades are already being built around the world. These include APERTIF (The Netherlands), ASKAP (Australia), e-MERLIN (UK), VLA (USA), e-EVN (based in Europe), LOFAR (The Netherlands), MeerKAT (South Africa), and the Murchison Widefield Array. Each of these new instruments has different strengths, and coordination of surveys between them can help maximise the science from each of them. A radio continuum survey is being planned on each of them with the primary science objective of understanding the formation and evolution of galaxies over cosmic time, and the cosmological parameters and large-scale structures which drive it. In pursuit of this objective, the different teams are developing a variety of new techniques, and refining existing ones. To achieve these exciting scientific goals, many technical challenges must be addressed by the survey instruments. Given the limited resources of the global radio-astronomical community, it is essential that we pool our skills and knowledge. We do not have sufficient resources to enjoy the luxury of re-inventing wheels. We face significant challenges in calibration, imaging, source extraction and measurement, classification and cross-identification, redshift determination, stacking, and data-intensive research. As these instruments extend the observational parameters, we will face further unexpected challenges in calibration, imaging, and interpretation. If we are to realise the full scientific potential of these expensive instruments, it is essential that we devote enough resources and careful study to understanding the instrumental effects and how they will affect the data. We have established an SKA Radio Continuum Survey working group, whose prime role is to maximise science from these instruments by ensuring we share resources and expertise across the projects. Here we describe these projects, their science goals, and the technical challenges which are being addressed to maximise the science return. © 2013 Astronomical Society of Australia.

Epoxy-coated bars as corrosion control in cracked reinforced concrete - Lõpez-Calvo, H.Z.; Montes-Garcia, P.; Kondratova, I.; Bremner, T.W.; Thomas, M.D.A. (Materials and Corrosion, 2013)
One of the most common corrosion protection methods in reinforcing concrete bars is the application of fusion-bonded epoxy coatings. Although considerable research has been carried out on the performance of epoxy-coated bars (ECR), there are still many uncertainties about their performance in cracked concrete. In this experimental program, reinforcing steel bars with six types of epoxy coatings embedded in concrete slabs with a 0.4 mm wide preformed crack intersecting the reinforcing steel at right angles were tested. Results of corrosion potentials, corrosion current density, coating adhesion tests, chloride content, and visual examination after 68 months of exposure to a simulated marine environment are reported. Results revealed that under the studied conditions the ECR did not provide total protection of steel reinforcement in cracked concrete. Their use however, tended to reduce significantly the damage caused by the chloride-induced corrosion when compared with the uncoated bars embedded in concrete with similar characteristics. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Keywords: Adhesion test; Corrosion current densities; Corrosion potentials; Cracked concretes; Epoxy coatings; Adhesion; Chlorine compounds; Coatings; Concrete slabs; Corrosion; Cracks; Epoxy resins; Reinforcement; Software testing; Concretes

The distance to NGC 1316 (Fornax A): Yet another curious case - Cantiello, M.; Grado, A.; Blakeslee, J.P.; Raimondo, G.; Di Rico, G.; Limatola, L.; Brocato, E.; Della Valle, M.; Gilmozzi, R. (Astronomy and Astrophysics, 2013)
Aims. The distance of NGC 1316, the brightest galaxy in the Fornax cluster, provides an interesting test for the cosmological distance scale. First, because Fornax is the second largest cluster of galaxies within â‰ 25 Mpc after Virgo and, in contrast to Virgo, has a small line-of-sight depth; and second, because NGC 1316 is the single galaxy with the largest number of detected Type Ia supernovae (SNe Ia), giving the opportunity to test the consistency of SNe Ia distances both internally and against other distance indicators. Methods. We measure surface brightness fluctuations (SBF) in NGC 1316 from ground- and space-based imaging data. The sample provides a homogeneous set of measurements over a wide wavelength interval. The SBF magnitudes, coupled with empirical and theoretical absolute SBF calibrations, are used to estimate the distance to the galaxy. We also present the first B-band SBF measurements of NGC 1316 and use them together with the optical and near-IR SBF data to analyze the properties of field stars in the galaxy. Results. We obtain mag, or d = 20.8 ± 0.5(stat.) ± 1.5(sys.) Mpc. When placed in a consistent Cepheid distance scale, our result agrees with the distances from other indicators. On the other hand, our distance is ~17% larger than the most recent estimate based on SNe Ia. Possible explanations for this disagreement are the uncertain level of internal extinction, and/or calibration issues. Concerning the stellar population analysis, we confirm the results from other spectro-photometric indicators: the field stars in NGC 1316 are dominated by a component with roughly solar metallicity and intermediate age. A non-negligible mismatch exists between B-band SBF models and data. We confirm that such behavior can be accounted for by an enhanced percentage of hot horizontal branch stars. Conclusions. Our study of the SBF distance to NGC 1316, and the comparison with distances from other indicators, raises some concern about the homogeneity between the calibrations of different indicators. If not properly placed in the same reference scale, significant differences can occur, with dramatic impact on the cosmological distance ladder. Our results on the stellar populations properties show that SBF data over a broad wavelength interval are an efficient means of studying the properties of unresolved systems in peculiar cases like NGC 1316. © 2013 ESO.
Keywords: Galaxies: clusters: individual: NGC 1316; Galaxies: distances and redshifts; Galaxies: elliptical and lenticular , CD; Galaxies: peculiar; Galaxies: photometry; Galaxies: stellar content; Calibration; Mobility aids for blind persons; Photometry; Population statistics; Stars; Galaxies

Picomolar inhibition of cholera toxin by a pentavalent ganglioside GM1os-calix[5]arene - Garcia-Hartjes, J.; Bernardi, S.; Weijers, C.A.G.M.; Wennekes, T.; Gilbert, M.; Sansone, F.; Casnati, A.; Zuilhof, H. (Organic and Biomolecular Chemistry, 2013)
Cholera toxin (CT), the causative agent of cholera, displays a pentavalent binding domain that targets the oligosaccharide of ganglioside GM1 (GM1os) on the periphery of human abdominal epithelial cells. Here, we report the first GM1os-based CT inhibitor that matches the valency of the CT binding domain (CTB). This pentavalent inhibitor contains five GM1os moieties linked to a calix[5]arene scaffold. When evaluated by an inhibition assay, it achieved a picomolar inhibition potency (IC50 = 450 pM) for CTB. This represents a significant multivalency effect, with a relative inhibitory potency of 100000 compared to a monovalent GM1os derivative, making GM1os-calix[5]arene one of the most potent known CTB inhibitors. This journal is © The Royal Society of Chemistry 2013.
Keywords: Binding domain; Calix[5]arene; Causative agents; Cholera toxin; Epithelial cells; Inhibition assays; Multivalency effects; Valencies; Positive ions; Chemistry

Characterization and optimization of vibration-assisted drilling of fibre reinforced epoxy laminates - Sadek, A.; Attia, M.H.; Meshreki, M.; Shi, B. (CIRP Annals - Manufacturing Technology, 2013)
Vibration-assisted drilling (VAD) can reduce thermal and mechanical defects associated with drilling of composites. Machinability maps are presented to establish the effect of the process parameters (speed, feed, frequency, and amplitude) in the low frequency-high amplitude regime (<200 Hz, <0.6 mm) on the hole quality attributes. The optimized VAD conditions can reduce the cutting temperature by 50% and the axial force by 40% and produce delamination-free holes, without affecting productivity. It is demonstrated that the intermittent cutting in VAD redistributes the cutting energy over the engagement cycles. This enhances the tool cooling and substantially reduces the axial force component. © 2013 CIRP.
Keywords: Cutting energy; Cutting temperature; Fibre-reinforced epoxy; Hole quality; Intermittent cutting; Mechanical defects; Process parameters; Vibration assisted drilling; Axial flow; Composite materials; Defects; Drilling; Optimization

Review of flexural strength of multi-year ice - Frederking, R.; Sudom, D. (Proceedings of the International Offshore and Polar Engineering Conference, 2013)
Flexural strength from dedicated beam tests and ramming of multi-year floes has been compared. Flexural strength of multi-year ice from beam tests indicates the strength decreases as the size of the beams increases and this is important in comparing flexural strength data from various sources. In terms of relative flexural strength; from strongest to weakest is fresh-water ice, multi-year ice and first-year sea ice. Ship ramming results provide comparative results for flexural strength, even if the absolute values are greater than would be expected given the thickness of the ice. Colder ice floes have greater flexural strength. The MV Arctic ramming tests indicate that multi-year floes in a small area can be quite variable in thickness, temperature and flexural strength. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE).
Keywords: Absolute values; Beam tests; Field test; First-year sea ices; Fresh-water; Ice floes; Multi-year ices; Small area; Sea ice; Bending strength

Optically pumped rolled-up InAs/InGaAsP quantum dash lasers at room temperature - Dastjerdi, M.H.T.; Djavid, M.; Arafin, S.; Liu, X.; Bianucci, P.; Mi, Z.; Poole, P.J. (Semiconductor Science and Technology, 2013)
We have investigated the fabrication and optical performance of free-standing rolled-up InGaAsP tube optical cavities, wherein self-organized InAs quantum dots or dashes are incorporated as the gain media. Such tubular optical cavities are formed when the coherently strained InAs/InGaAsP quantum dot/dash nanomembrane is selectively released from the host substrate. We have achieved lasing from rolled-up InAs/InGaAsP quantum dash microtubes at room temperature under continuous wave optical pumping. The measured threshold is ∼6 W, and the Purcell factor and the spontaneous emission coupling factor are estimated to be ∼6.54 and ∼0.87, respectively. © 2013 IOP Publishing Ltd.
Keywords: Continuous Wave; Coupling factor; InAs quantum dots; Optical cavities; Optical performance; Optically pumped; Quantum dashes; Room temperature; Magnetic materials; Semiconductor devices; Optical pumping

Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013) - Murray, K.K.; Boyd, R.K.; Eberlin, M.N.; John Langley, G.; Li, L.; Naito, Y. (Pure and Applied Chemistry, 2013)
This document contains recommendations for terminology in mass spectrometry. Development of standard terms dates back to 1974 when the IUPAC Commission on Analytical Nomenclature issued recommendations on mass spectrometry terms and definitions. In 1978, the IUPAC Commission on Molecular Structure and Spectroscopy updated and extended the recommendations and made further recommendations regarding symbols, acronyms, and abbreviations. The IUPAC Physical Chemistry Division Commission on Molecular Structure and Spectroscopy's Subcommittee on Mass Spectroscopy revised the recommended terms in 1991 and appended terms relating to vacuum technology. Some additional terms related to tandem mass spectrometry were added in 1993 and accelerator mass spectrometry in 1994. Owing to the rapid expansion of the field in the intervening years, particularly in mass spectrometry of biomolecules, a further revision of the recommendations has become necessary. This document contains a comprehensive revision of mass spectrometry terminology that represents the current consensus of the mass spectrometry community. © 2013 IUPAC.
Keywords: Accelerator mass spectrometry; Definitions; IUPAC analytical Chemistry division; Mass spectroscopy; Rapid expansion; Tandem mass spectrometry; Terms; Glossaries; Molecular structure; Physical chemistry; Terminology; Vacuum technology; Mass spectrometry

Microbial expression profiles in the rhizosphere of willows depend on soil contamination - Yergeau, E.; Sanschagrin, S.; Maynard, C.; St-Arnaud, M.; Greer, C.W. (ISME Journal, 2013)
The goal of phytoremediation is to use plants to immobilize, extract or degrade organic and inorganic pollutants. In the case of organic contaminants, plants essentially act indirectly through the stimulation of rhizosphere microorganisms. A detailed understanding of the effect plants have on the activities of rhizosphere microorganisms could help optimize phytoremediation systems and enhance their use. In this study, willows were planted in contaminated and non-contaminated soils in a greenhouse, and the active microbial communities and the expression of functional genes in the rhizosphere and bulk soil were compared. Ion Torrent sequencing of 16S rRNA and Illumina sequencing of mRNA were performed. Genes related to carbon and amino-acid uptake and utilization were upregulated in the willow rhizosphere, providing indirect evidence of the compositional content of the root exudates. Related to this increased nutrient input, several microbial taxa showed a significant increase in activity in the rhizosphere. The extent of the rhizosphere stimulation varied markedly with soil contamination levels. The combined selective pressure of contaminants and rhizosphere resulted in higher expression of genes related to competition (antibiotic resistance and biofilm formation) in the contaminated rhizosphere. Genes related to hydrocarbon degradation were generally more expressed in contaminated soils, but the exact complement of genes induced was different for bulk and rhizosphere soils. Together, these results provide an unprecedented view of microbial gene expression in the plant rhizosphere during phytoremediation.The ISME Journal advance online publication, 26 September 2013; doi:10.1038/ismej.2013.163.

Quercetin deformable liposome: Preparation and efficacy against ultraviolet B induced skin damages in vitro and in vivo - Liu, D.; Hu, H.; Lin, Z.; Chen, D.; Zhu, Y.; Hou, S.; Shi, X. (Journal of Photochemistry and Photobiology B: Biology, 2013)
Ultraviolet (UV) radiation has deleterious effects on cells through direct damage to DNA or through increasing generation of reactive oxygen species (ROS). The flavonol quercetin (Qu) provides cellular protection against UV radiation and the current investigation was carried out to develop a deformable liposome formulation of Qu to enhance its delivery into human skin and to improve its anti-UVB effect. The influence of surfactants (including Span 20, Tween 80 and sodium cholate) on the properties of Qu deformable liposomes was investigated. Liposomes composed of Qu, phosphatidylcholine (PC), cholesterol (Chol), and Tween 80 showed high entrapment efficiencies (80.41 ± 4.22%), small particle sizes (132 ± 14 nm), high elasticity (10.48 ± 0.71), and prolonged drug release. The cell viability in UVB-irradiated HaCaT cells increased to 89.89 ± 4.5% at 24 h and 78.8 ± 3.19% at 48 h following treatment with Qu defomable liposomes. The ROS and malondialdehyde (MDA) level were also reduced. The penetration rate was 3.8-fold greater than that of the Qu suspension. Moreover, the edema and inflammation was alleviated by Qu deformable liposomes. These results showed the potential of deformable liposomes to enhance the anti-UVB effects of Qu both in vitro and in vivo. © 2013 Elsevier B.V. All rights reserved.
Keywords: 3,4 methylenedioxyamphetamine; cholesterol; cholic acid; liposome; malonaldehyde; phosphatidylcholine; polysorbate 80; quercetin; reactive oxygen metabolite; sorbitan laurate; animal cell; animal experiment; article; cell membrane; cell protection; cell viability; controlled study; dermatitis; drug delivery system; drug efficacy; drug formulation; drug release; drug solubility; drug synthesis; elasticity; encapsulation; histopathology; in vitro study; in vivo study; keratinocyte; lipid peroxidation; male; nonhuman; oxidative stress; particle size; priority journal; rat; skin defect; skin edema; stratum corneum; ultraviolet B radiation; ultraviolet irradiation; zeta potential

Thermo-responsive photoluminescent polymer brushes device as a platform for selective detection of Cr(vi) - Yang, X.; Jiang, Y.; Shen, B.; Chen, Y.; Dong, F.; Yu, K.; Yang, B.; Lin, Q. (Polymer Chemistry, 2013)
In this work, we first report a thermo-responsive photoluminescent polymer brushes device as a platform for the selective and sensitive detection of Cr(vi). Positively charged fluorescent molecules of a quaternary ammonium tetraphenylethylene derivative (d-TPE) are immobilized in the thermo-responsive polymer brushes of p(NIPAM-co-AAc) by Coulombic force, which leads to the observation of an immobilized induced emission (IIE) phenomenon. The emission intensity of the d-TPE labelled film is improved hundreds of times compared with a d-TPE aqueous solution. As a result, we obtain a novel thermo-responsive polymer brushes device with excellent photoluminescent properties. The photoluminescence (PL) intensity of the device exhibits a linear and reversible response from 4 to 60 °C and shows a high PL quenching for the sensitive and selective detection of Cr(vi) rather than Cr(iii). The limit of detection can reach as low as 0.05 ppm, which indicates a promising sensor device for environmental monitoring, laboratory analysis and various other applications. This journal is © The Royal Society of Chemistry.
Keywords: Environmental Monitoring; Fluorescent molecules; Laboratory analysis; Photo-luminescent properties; Photoluminescence intensities; Quaternary ammonium; Selective detection; Thermoresponsive polymer; Chromium compounds; Sensors; Dendrimers

Natural fiber composites - Hamada, H.; Denault, J.; Mohanty, A.K.; Li, Y.; Aly-Hassan, M.S. (Advances in Mechanical Engineering, 2013)

A graph-partitioning framework for aligning hierarchical topic structures to presentations - Zhu, X.; Cherry, C.; Penn, G. (IEEE Transactions on Audio, Speech and Language Processing, 2013)
This paper studies the problem of imposing an existing hierarchical semantic structure onto a corresponding spoken document in which the structures are embedded, with the goal of indexing such documents for easier access. We propose a graph-partitioning framework to solve a semantic tree-to-string alignment problem through optimizing a normalized-cut criterion. We present models with different modeling capabilities and time complexities in this framework and provide experimental evidence of their performance. We relate graph partitioning to conventional dynamic time warping (DTW) as it applies to this problem, and show that the proposed framework can naturally include topic segmentation to accommodate cohesion constraints. © 2006-2012 IEEE.
Keywords: Graph Partitioning; minimum-cut; Semantic structures; Spoken document; Topic structures; Alignment; Graph theory; Mapping; Semantics; Indexing (of information)

Electrochemical behavior of Zn/Zn(II) couples in aprotic ionic liquids based on pyrrolidinium and imidazolium cations and bis(trifluoromethanesulfonyl) imide and dicyanamide anions - Xu, M.; Ivey, D.G.; Xie, Z.; Qu, W. (Electrochimica Acta, 2013)
Motivated by the potential of using room temperature ionic liquids (RTILs) as electrolytes to replace traditional aqueous electrolytes for Zn-anode secondary batteries, Zn/Zn(II) redox reactions have been studied in four aprotic RTILs based on pyrrolidinium ([Pyrr]+) and imidazolium ([Im] +) cations, and bis(trifluoromethanesulfonyl)imide ([TFSI] -) and dicyanamide ([DCA]-) anions. Cyclic voltammetry results suggest a smaller overpotential for Zn redox in [Im]+ cation based and [DCA]- anion based RTILs than in [Pyrr]+ and [TFSI]- based RTILs. Potentiodynamic polarization experiments indicate a strong dependence of the electrode reaction mechanism for the Zn species on the RTIL anions. In [TFSI]- based RTILs, Zn2+ ions are the electroactive species, with the electrode reaction being a single-step, two-electron transfer process. In [DCA]- based RTILs, two-step, single-electron reactions account for the electrode mechanism. The exchange current densities derived from Tafel analysis for the Zn species in the four RTILs are greater than 10-3 mA/cm2, with the [Im]+ cation based RTIL possessing the highest value of 9.9 × 10-3 mA/cm2. The results obtained will assist in obtaining a better understanding of the electrochemical behavior of Zn in RTILs, shedding light on the development of RTILs for Zn-anode secondary batteries. © 2012 Elsevier Ltd. All Rights Reserved.
Keywords: Aprotic; Aqueous electrolyte; Bis(trifluoromethane sulfonyl)imide; Dicyanamide; Dicyanamide anion; Electroactive species; Electrochemical behaviors; Electrode mechanism; Electrode reaction mechanisms; Electrode reactions; Exchange current densities; Imidazolium; Imidazolium cation; Overpotential; Pyrrolidinium; Room temperature ionic liquids; Shedding light; Single electron; Single-step; Strong dependences; Tafel analysis; Two-electron transfer; Cyclic voltammetry; Electrolytes; Ionic liquids; Negative ions; Positive ions; Potentiodynamic polarization; Redox reactions; Secondary batteries; Zinc

Microwave-assisted acid digestion protocol for the determination of methionine and selenomethionine in selenium-enriched yeast by species specific isotope dilution GC-MS - Yang, L.; Maxwell, P.; Mester, Z. (Analytical Methods, 2013)
A quantitative and fast microwave assisted protein digestion method is described for the simultaneous determination of methionine (Met) and selenomethionine (SeMet) in yeast. Extraction of Met and SeMet from the selenized yeast was performed in a focused microwave system using methanesulfonic acid (MSA). The effects of parameters such as extraction time, temperature, power and sample mass on the extraction efficiencies of Met and SeMet were investigated. Species specific isotope dilution (ID) calibration using 13C enriched Met and SeMet spikes was employed to obtain accurate results. Analytes were derivatized with methyl chloroformate and extracted into chloroform prior to species specific ID GC-MS analysis. Using a 20 minute extraction time at 165 °C and 6 ml of 4 M MSA was found to be efficient for both analytes based on a 50 mg sample mass. Under these conditions, concentrations of 5862 ± 32 and 3366 ± 60 μg g -1 (one standard deviation, n = 3) for Met and SeMet, respectively, were obtained in SELM-1 yeast certified reference material (CRM). The obtained results are in good agreement with the certified values of 5758 ± 277 and 3448 ± 146 μg g-1 (expanded uncertainty, k = 2). Compared to previous MSA reflux digestion, this newly proposed method offers dramatic reduction in extraction time from 8-16 hours of the conventional MSA reflux to 20 minutes by microwave extraction, significantly improving the sample throughput. Additionally, the microwave extraction is fully automated and uses 75% less reagent (MSA) than the conventional acid reflux setup. The developed method is suitable for quasi real time production monitoring of Met and SeMet in Se enriched yeast and other food products. This journal is © 2013 The Royal Society of Chemistry.
Keywords: Analytes; As extraction; Certified reference materials; Certified values; Conventional acids; Extraction efficiencies; Extraction time; Focused microwaves; GC-MS analysis; Methane sulfonic acid; Methyl chloroformate; Microwave assisted; Microwave extraction; Microwave-assisted acid digestion; Protein digestion; Real-time production; Selenized yeast; Selenomethionine; Simultaneous determinations; Species-specific isotope dilution; Standard deviation; Amino acids; Food products; Isotopes; Microwaves; Selenium; Selenium compounds; Yeast

Bacterial growth at -15 °C; molecular insights from the permafrost bacterium Planococcus halocryophilus Or1 - Mykytczuk, N.C.S.; Foote, S.J.; Omelon, C.R.; Southam, G.; Greer, C.W.; Whyte, L.G. (ISME Journal, 2013)
Planococcus halocryophilus strain Or1, isolated from high Arctic permafrost, grows and divides at -15 °C, the lowest temperature demonstrated to date, and is metabolically active at -25 °C in frozen permafrost microcosms. To understand how P. halocryophilus Or1 remains active under the subzero and osmotically dynamic conditions that characterize its native permafrost habitat, we investigated the genome, cell physiology and transcriptomes of growth at -15 °C and 18% NaCl compared with optimal (25 °C) temperatures. Subzero growth coincides with unusual cell envelope features of encrustations surrounding cells, while the cytoplasmic membrane is significantly remodeled favouring a higher ratio of saturated to branched fatty acids. Analyses of the 3.4 Mbp genome revealed that a suite of cold and osmotic-specific adaptive mechanisms are present as well as an amino acid distribution favouring increased flexibility of proteins. Genomic redundancy within 17% of the genome could enable P. halocryophilus Or1 to exploit isozyme exchange to maintain growth under stress, including multiple copies of osmolyte uptake genes (Opu and Pro genes). Isozyme exchange was observed between the transcriptome data sets, with selective upregulation of multi-copy genes involved in cell division, fatty acid synthesis, solute binding, oxidative stress response and transcriptional regulation. The combination of protein flexibility, resource efficiency, genomic plasticity and synergistic adaptation likely compensate against osmotic and cold stresses. These results suggest that non-spore forming P. halocryophilus Or1 is specifically suited for active growth in its Arctic permafrost habitat (ambient temp. ~ -16 °C), indicating that such cryoenvironments harbor a more active microbial ecosystem than previously thought. © 2013 International Society for Microbial Ecology.
Keywords: adaptation; bacterium; cytology; fatty acid; genomics; growth rate; metabolism; microcosm; osmosis; permafrost; phenotypic plasticity; physiology; synergism; Bacteria (microorganisms); Planococcus (bacterium)

Ab initio potential energy and dipole moment surfaces for CS2: Determination of molecular vibrational energies - Pradhan, E.; Carreón-Macedo, J.-L.; Cuervo, J.E.; Schröder, M.; Brown, A. (The Journal of Physical Chemistry A, 2013)
The ground state potential energy and dipole moment surfaces for CS 2 have been determined at the CASPT2/C:cc-pVTZ,S:aug-cc-pV(T+d)Z level of theory. The potential energy surface has been fit to a sum-of-products form using the neural network method with exponential neurons. A generic interface between neural network potential energy surface fitting and the Heidelberg MCTDH software package is demonstrated. The potential energy surface has also been fit using the potfit procedure in MCTDH. For fits to the low-energy regions of the potential, the neural network method requires fewer parameters than potfit to achieve high accuracy; global fits are comparable between the two methods. Using these potential energy surfaces, the vibrational energies have been computed for the four most abundant CS2 isotopomers. These results are compared to experimental and previous theoretical data. The current potential energy surfaces are shown to accurately reproduce the low-lying vibrational energies within a few wavenumbers. Hence, the potential energy and dipole moments surfaces will be useful for future study on the control of quantum dynamics in CS2. © 2012 American Chemical Society.
Keywords: Ab initio potentials; Current potential; Dipole moment surfaces; Generic interfaces; Ground state potential; Low energy regions; Neural network method; Vibrational energies; Dipole moment; Neural networks; Potential energy; Potential energy surfaces; Quantum chemistry

The concept of 2D gated imaging for particle sizing in a laminar diffusion flame - Hadef, R.; Geigle, K.P.; Zerbs, J.; Sawchuk, R.A.; Snelling, D.R. (Applied Physics B: Lasers and Optics, 2013)
In this work, time-resolved laser-induced incandescence (TiRe LII) has been employed to measure primary particle diameters of soot in an atmospheric laminar ethylene diffusion flame. The generated data set complements existing data determined in one single location and takes advantage of the good spatial resolution of the ICCD detection. Time resolution is achieved by shifting the camera gate along the LII decay. One key input parameter for the analysis of time-resolved LII is the local flame temperature. This was determined on a grid throughout the flame by coherent anti-Stokes Raman scattering. The accurate temperature data, in combination with other published data from this flame, are well suited for soot model validation purposes while we showed feasibility of a shifted gate approach to deduce 2D particle sizes in the chosen standard flame. © 2013 Springer-Verlag Berlin Heidelberg.

The importance of water transport on short-side chain perfluorosulfonic acid membrane fuel cells operating under low relative humidity - Zhao, N.; Edwards, D.; Lei, C.; Wang, K.; Li, J.; Zhang, Y.; Holdcroft, S.; Shi, Z. (Journal of Power Sources, 2013)
Polarization curves of fuel cells incorporating PFSA short-side chain (SSC) ionomer membranes having ion exchange capacity (IEC) 1.30, 1.37, 1.43 and 1.50 meq g-1 and NRE-211 are compared. Under low humidity conditions, fuel cells incorporating SSC membranes show higher performance than NRE-211. SSC PFSA membranes possessing an IEC of 1.37 meq g-1 exhibit the highest performance. Differences in fuel cell polarization curves are due to differences in the high frequency resistance, which in turn is found related to ex-situ measurements of both the effective proton mobility and the rate of water flux through the membrane, which also exhibit a maximum for membranes of IEC 1.37 meq g-1. Water permeation and proton mobility are shown to be inherently linked, but it is found that simply increasing the membrane's IEC does not necessarily translate to increased water transport and effective proton mobility, despite the increased water content. © 2013 Crown Copyright and Elsevier Inc.

Methods and applications of serological proteome analysis - Fulton, K.M.; Martin, S.S.; Wolfraim, L.; Twine, S.M. (Methods in Molecular Biology, 2013)
The study of the humoral response to infectious diseases and chronic diseases, such as cancer, is important for many reasons, including understanding the host response to disease, identification of protective antigens, vaccine development, and discovery of biomarkers for early diagnosis. During the past decade, proteomic approaches, such as serological proteome analysis (SERPA), have been used to identify the repertoire of immunoreactive proteins in various diseases. In this chapter, we provide an outline of the SERPA approach, using the analysis of sera from mice vaccinated with a live attenuated tularemia vaccine as an example. © 2013 Springer Science+Business Media, LLC.
Keywords: proteome; tularemia vaccine; article; blood analysis; immunoblotting; immunoreactivity; isoelectric focusing; mouse; nonhuman; polyacrylamide gel electrophoresis; priority journal; protein analysis; serological proteome analysis; serology; two dimensional gel electrophoresis; vaccination; Western blotting

Herschel * Observations of the W3 GMC: Clues to the formation of clusters of high-mass stars - Rivera-Ingraham, A.; Martin, P.G.; Polychroni, D.; Motte, F.; Schneider, N.; Bontemps, S.; Hennemann, M.; Men'Shchikov, A.; Luong, Q.N.; André, Ph.; Arzoumanian, D.; Bernard, J.-Ph.; et al. (The Astrophysical Journal, 2013)
The W3 GMC is a prime target for the study of the early stages of high-mass star formation. We have used Herschel data from the HOBYS key program to produce and analyze column density and temperature maps. Two preliminary catalogs were produced by extracting sources from the column density map and from Herschel maps convolved to 500 μm resolution. Herschel reveals that among the compact sources (FWHM < 0.45 pc), W3 East, W3 West, and W3 (OH) are the most massive and luminous and have the highest column density. Considering the unique properties of W3 East and W3 West, the only clumps with ongoing high-mass star formation, we suggest a "convergent constructive feedback" scenario to account for the formation of a cluster with decreasing age and increasing system/source mass toward the innermost regions. This process, which relies on feedback by high-mass stars to ensure the availability of material during cluster formation, could also lead to the creation of an environment suitable for the formation of Trapezium-like systems. In common with other scenarios proposed in other HOBYS studies, our results indicate that an active/dynamic process aiding in the accumulation, compression, and confinement of material is a critical feature of the high-mass star/cluster formation, distinguishing it from classical low-mass star formation. The environmental conditions and availability of triggers determine the form in which this process occurs, implying that high-mass star/cluster formation could arise from a range of scenarios: from large-scale convergence of turbulent flows to convergent constructive feedback or mergers of filaments. © 2013. The American Astronomical Society. All rights reserved..

Optimization of MOCVD-diffused p-InP for planar avalanche photodiodes - Pitts, O.J.; Hisko, M.; Benyon, W.; Raymond, S.; SpringThorpe, A.J. (Journal of Crystal Growth, 2013)
We investigate the materials properties and dark currents of planar InP/InGaAs avalanche photodiodes (APDs) in which the p-dopant, Zn, is introduced by diffusion in an MOCVD reactor using dimethylzinc (DMZn) as the source. APD dark currents are compared with low-temperature photoluminescence (PL), electrochemical capacitance-voltage (ECV) and secondary ion mass spectroscopy (SIMS) measurements of layers diffused under the same set of conditions. Device dark currents exhibit both surface-related and bulk contributions, with the bulk contribution appearing as a step increase in the current near the punch-through voltage. The bulk dark current contribution depends on the diffusion process parameters and is correlated with the total Zn incorporation and the intensities of the InP and InGaAs PL peaks. A variation of three orders of magnitude is observed in the bulk dark current contribution as diffusion conditions are varied. © 2013.

Hydrogen absorption into titanium under cathodic polarization: An in-situ neutron reflectometry and EIS study - Vezvaie, M.; Noël, J.J.; Tun, Z.; Shoesmith, D.W. (Journal of the Electrochemical Society, 2013)
Hydrogen (deuterium) absorption into sputter-coated titanium (Ti) film electrodes during cathodic polarization in heavy water (D2O) was monitored using in-situ neutron reflectometry (NR) and electrochemical impedance spectroscopy (EIS). The scattering length density (SLD) of Ti metal increased with increasing cathodic polarization, due to the penetration of deuterium through the surface oxide and into the underlying metal. The rate of D absorption estimated from the NR data showed a pattern with four distinctive regions separated by potential boundaries between -0.35 and -0.4 VSCE and around ∼-0.6 VSCE. EIS results support division of the behavior into these potential ranges. Hydrogen absorption by Tiwas observed at potentials <∼-0.35 VSCE, where the capacitance and resistance of the TiO2 layer dramatically changed. At this point, the D content of the film quickly achieved a level of ∼900 ppm by weight (atom ratio D:Ti ∼ 0.04). Decreased absorption kinetics were observed over the potential region from ∼-0.40 VSCE to -0.6 VSCE, indicating that D absorption was controlled either by a diffusion process through the TiO 2 layer or by the formation of blocking hydrides at the Ti/TiO 2 interface, at the base of the defective locations in the oxide through which the hydrogen was entering. Significant increases in the current density and SLD of the Ti film at potentials more negative than -0.6 V SCE were assigned to widespread hydrogen absorption and TiH x growth within the metal. These observations are consistent with hydrogen ingress through the oxide film, probably via weak points containing electronic defects and disorder, such as grain boundaries and triple points, at potentials as mild as ∼-0.4 VSCE, and with hydrogen penetration through continuous, intact oxide via the previously published redox transformation mechanism, at potentials more negative than -0.6 VSCE. © 2013 The Electrochemical Society. All rights reserved.
Keywords: Absorption kinetics; Diffusion process; Electronic defects; Hydrogen absorption; Hydrogen penetration; Neutron reflectometry; Redox transformations; Scattering length density; Cathodic polarization; Deuterium; Electrochemical impedance spectroscopy; Film growth; Grain boundaries; Heavy water; Neutron reflection; Oxide films; Titanium; Titanium dioxide; Hydrogen

Polarization management for silicon photonic integrated circuits - Dai, D.; Liu, L.; Gao, S.; Xu, D.-X.; He, S. (Laser and Photonics Reviews, 2013)
Polarization management is very important for photonic integrated circuits (PICs) and their applications. Due to geometrical anisotropy and fabrication inaccuracies, the characteristics of the guided transverse-electrical (TE) and transverse-magnetic (TM) modes are generally different. Polarization-dependent dispersion and polarization-dependent loss are such manifestations in PICs. These issues become more severe in high index contrast structures such as nanophotonic waveguides made of silicon-on-insulator (SOI), which has been regarded as a good platform for optical interconnects because of the compatibility with CMOS processing. Recently, polarization division multiplexing (PDM) with coherent detection using silicon photonics has also attracted much attention. This trend further highlights the importance of polarization management in silicon PICs. The authors review their work on polarization management for silicon PICs using the polarization independence and polarization diversity methods. Polarization issues and solutions in PICs made of SOI nanowires and ridge waveguides are discussed. © 2012 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Keywords: Nonlinear; Photonic integrated circuits; Polarization dependent loss; Polarization division multiplexing (PDM); Polarization independence; Rotator; Silicon photonic integrated circuits; Splitter; Nanophotonics; Nanowires; Optical interconnects; Optical waveguides; Photonic devices; Photonic integration technology; Photonics; Polarization; Ridge waveguides; Silicon; Waveguides; Multiplexing

Proteomics analysis suggests broad functional changes in potato leaves triggered by phosphites and a complex indirect mode of action against Phytophthora infestans - Lim, S.; Borza, T.; Peters, R.D.; Coffin, R.H.; Al-Mughrabi, K.I.; Pinto, D.M.; Wang-Pruski, G. (Journal of Proteomics, 2013)
Phosphite (salts of phosphorous acid; Phi)-based fungicides are increasingly used in controlling oomycete pathogens, such as the late blight agent Phytophthora infestans. In plants, low amounts of Phi induce pathogen resistance through an indirect mode of action. We used iTRAQ-based quantitative proteomics to investigate the effects of phosphite on potato plants before and after infection with P. infestans. Ninety-three (62 up-regulated and 31 down-regulated) differentially regulated proteins, from a total of 1172 reproducibly identified proteins, were identified in the leaf proteome of Phi-treated potato plants. Four days post-inoculation with P. infestans, 16 of the 31 down-regulated proteins remained down-regulated and 42 of the 62 up-regulated proteins remained up-regulated, including 90% of the defense proteins. This group includes pathogenesis-related, stress-responsive, and detoxification-related proteins. Callose deposition and ultrastructural analyses of leaf tissues after infection were used to complement the proteomics approach. This study represents the first comprehensive proteomics analysis of the indirect mode of action of Phi, demonstrating broad effects on plant defense and plant metabolism. The proteomics data and the microscopy study suggest that Phi triggers a hypersensitive response that is responsible for induced resistance of potato leaves against P. infestans. Biological significance: Phosphie triggers complex functional changes in potato leaves that are responsible for the induced resistance against Phytophthora infestans.This article is part of a Special Issue entitled: Translational Plant Proteomics. © 2013 Elsevier B.V.

Over-expression of x-linked inhibitor of apoptosis protein modulates multiple aspects of neuronal Ca2+ signaling - Grant, J.; Parker, K.; Moore, C.S.; Keddy, P.G.W.; Mayne, M.; Robertson, G.S. (Neurochemical Research, 2013)
X-linked inhibitor of apoptosis (XIAP) protects and preserves the function of neurons in both in vitro and in vivo models of excitotoxicity. Since calcium (Ca2+) overload is a pivotal event in excitotoxic neuronal cell death, we have determined whether XIAP over-expression influences Ca 2+-signaling in primary cultures of mouse cortical neurons. Using cortical neuron cultures derived from wild-type (Wt) mice transiently transfected with XIAP or from transgenic mice that over-express XIAP, we show that XIAP opposes the rise in intracellular Ca2+ concentration by a variety of triggers. Relative to control neurons, XIAP over-expression produced a slight, but significant, elevation of resting Ca2+ concentrations. By contrast, the rise in intracellular Ca2+ concentrations produced by N-methyl-d-aspartate receptor stimulation and voltage gated Ca2+ channel activation were markedly attenuated by XIAP over-expression. The release of Ca2+ from intracellular stores induced by the sarco/endoplasmic reticulum Ca2+ ATPase inhibitor thapsigargin was also inhibited in neurons transiently transfected with XIAP. The pan-caspase inhibitor zVAD did not, however, diminish the rise in intracellular Ca2+ concentrations elicited by l-glutamate suggesting that XIAP influences Ca2+ signaling in a caspase-independent manner. Taken together, these findings demonstrate that the ability of XIAP to block excessive rises in intracellular Ca2+ by a variety of triggers may contribute to the neuroprotective effects of this anti-apoptotic protein. © 2013 Springer Science+Business Media New York.
Keywords: benzyloxycarbonylvalylalanylaspartyl fluoromethyl ketone; calcium ion; glutamic acid; n methyl dextro aspartic acid receptor; thapsigargin; voltage gated calcium channel; X linked inhibitor of apoptosis; animal cell; animal tissue; article; brain cortex; brain nerve cell; calcium cell level; calcium signaling; controlled study; embryo; female; male; mouse; neuromodulation; neuroprotection; nonhuman; priority journal; protein analysis; protein expression; protein function; receptor upregulation; transgenic mouse; transient transfection; wild type; Animals; Apoptosis; Calcium; Calcium Signaling; Glutamic Acid; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neurons; Neuroprotective Agents; Oligopeptides; Thapsigargin; X-Linked Inhibitor of Apoptosis Protein; Mus; Mus musculus

Thermomechanical fatigue crack growth from laser drilled holes in single crystal nickel based superalloy - Kersey, R.K.; Staroselsky, A.; Dudzinski, D.C.; Genest, M. (International Journal of Fatigue, 2013)
The test results undergoing thermomechanical fatigue of single crystal PWA1484 crack growth showed that the life of TMF specimens with notches (in this case laser drilled holes) is 4 times shorter than the number of cycles to failure observed on smooth gage section specimens (without holes) under the same loading conditions. Such a significant change in number of cycles to failure must be accounted in any damage tolerant turbine airfoil design system. The detailed fractographic analysis demonstrated that all cracks start crystallographically along the {1 1 1} octahedral crystallographic planes and later change to mixed mode fracture. Most of the crack propagation takes place at the low temperature portion of the cycle in the out-of-phase test; however there is noticeable damage accumulation during the high temperature compressive load portion of the cycle. Crack propagation under TMF loading conditions is considerably faster than corresponding isothermal LCF crack growth tested at the temperature and similar loading conditions of the tensile part of the TMF cycle. As results show, the applicability of the LEFM methods for single crystal TMF crack growth prediction is limited and at least should consist of mixed mode crack analysis. A new method for detecting cracks during a TMF test using induction thermography was employed. This method, coined the Active Inferred Crack Detection System (AICD), demonstrated high effectiveness in following crack progression under cyclic loading making it well suited to perform TMF crack growth testing. Using this experimental technique we also investigated the effect of secondary crystallographic orientation on crack propagation. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Crack growth prediction; Crystallographic orientations; Crystallographic plane; Experimental techniques; Notch; Number of cycles to failure; Single crystal nickel based superalloy; Thermo mechanical fatigues (TMF); Crack detection; Crack propagation; Single crystals; Superalloys; Cracks

Estimating probability of detection from in-service inspection data - Khan, M.; Liao, M. (Canadian Aeronautics and Space Journal, 2013)
Due to the complexity of real structures and in-service environment, the probability of detection (POD) curve generated from a laboratory environment and simple coupon samples may not be representative of in-service nondestructive inspection capability and experience. A study was carried out to assess the capability of a recent Berens model to estimate the POD using in-service inspection data. This paper presents the Berens model as well as the results of five case studies, where two types of mean POD curves were estimated and compared with each other. The first POD estimation used the standard POD method, described in the Military Handbook 1823, and used both hit and miss (detected and nondetected cracks) data. The second POD estimation used the Berens model and only hit (detected cracks) and percentage of crack detection (number of detected cracks per number of inspected sites) data. It is shown that the a90 values estimated by the Berens model are close to those from the first POD approach, especially when the percentage of crack detection is known. The study demonstrated the possibility of using the Berens model for estimating an "effective" POD curve from in-service data, where often not all data required by the standard POD approach are available. © 2013 Government of Canada.
Keywords: Hit and miss; In-service datum; In-service inspection; Laboratory environment; Non destructive inspection; POD method; Probability of detection; Real structure; Cracks; Estimation; Inspection; Crack detection

Nanocomposites of nanocrystalline cellulose for enzyme immobilization - Incani, V.; Danumah, C.; Boluk, Y. (Cellulose, 2013)
We describe the synthesis, characterization and use of a composite material made of a renewable source and metallic nanoparticles for biosensing applications. Nanocrystalline cellulose (NCC) is a product isolated from natural cellulose fibers, which is of approximately 100 nm long and 10 nm wide in size. We augmented the surface area and tailored the chemical affinity of NCC by optimally dressing it with gold nanoparticles (AuNPs). The deposition of AuNPs on NCC was controlled by using cationic polyethylenimine (PEI) at different pHs. AuNPs were thiol-functionalized using different linkers prior to enzyme immobilization. The enzyme (glucose oxidase or GOx) was conjugated on the composite by carbodiimide coupling, and subsequent activation of linker-carboxylic acid group. Our results showed that GOx was attached to the surface of the NCC nanocomposite. Moreover, the amount of GOx loaded onto the support depended on the length of the thiol-linker used. The lower value (20. 3 mg/mg of support) was obtained with the longer thiol-linker (11 carbon chain) compared to 25. 2 mg/mg of support for the smaller thiol-linker (3 carbon chain). © 2012 Springer Science+Business Media Dordrecht.
Keywords: Acid groups; Biosensing applications; Carbodiimides; Carbon chains; Cationic polyethylenimine; Chemical affinities; Gold nanoparticle; Metallic nanoparticles; Nanocrystalline cellulose; Natural cellulose fibers; Renewable sources; Surface area; Biosensors; Carbon; Carboxylic acids; Cellulose derivatives; Glucose sensors; Gold; Metal nanoparticles; Nanocomposites; Synthesis (chemical); Enzyme immobilization; Carboxylic Acids; Cellulose Derivatives; Composites; Crystallites; Gold Compounds; Sensors; Synthesis

PCSK9 Prosegment chimera as novel inhibitors of LDLR degradation - Luna Saavedra, Y.G.; Zhang, J.; Seidah, N.G. (PLoS ONE, 2013)
The proprotein convertase PCSK9, a target for the treatment of hypercholesterolemia, is a negative regulator of the LDL receptor (LDLR) leading to its degradation in endosomes/lysosomes and up-regulation of plasma LDL-cholesterol levels. The proprotein convertases, a family of nine secretory serine proteases, are first synthesized as inactive zymogens. Except for PCSK9, all other convertases are activated following the autocatalytic excision of their inhibitory N-terminal prosegment. PCSK9 is unique since the mature enzyme exhibits a cleaved prosegment complexed with the catalytic subunit and has no protease activity towards other substrates. Similar to other convertases, we hypothesized that the in trans presence of the PCSK9 prosegment would interfere with PCSK9's activity on the LDLR. Since the prosegment cannot be secreted alone, we engineered a chimeric protein using the Fc-region of human IgG1 fused to the PCSK9 prosegment. The expression of such Fcpro-fusion protein in HEK293 and HepG2 cells resulted in a secreted protein that binds PCSK9 and markedly inhibits its activity on the LDLR. This was observed by either intracellular co-expression of PCSK9 and Fcpro or by an extracellular in vitro co-incubation of Fcpro with PCSK9. Structure-function studies revealed that the inhibitory function of Fcpro does not require the acidic N-terminal stretch (residues 31-58) nor the C-terminal Gln152 of the prosegment. Fcpro likely interacts with the prosegment and/or catalytic subunit of the prosegment≡PCSK9 complex thereby allosterically modulating its function. Our data suggest a novel strategic approach for the design and isolation of PCSK9 inhibitors. © 2013 Luna Saavedra et al.
Keywords: immunoglobulin G1; low density lipoprotein receptor; PCSK9 inhibitor; proteinase inhibitor; recombinant Fcpro protein; recombinant protein; unclassified drug; amino terminal sequence; article; carboxy terminal sequence; cell strain HEK293; cell strain HepG2; controlled study; down regulation; enzyme active site; enzyme activity; human; human cell; in vitro study; protein binding; protein degradation; protein domain; protein expression; protein function; protein protein interaction; protein secretion

Method for isolation and molecular characterization of extracellular microvesicles released from brain endothelial cells - Haqqani, A.S.; Delaney, C.E.; Tremblay, T.-L.; Sodja, C.; Sandhu, J.K.; Stanimirovic, D.B. (Fluids and Barriers of the CNS, 2013)
Background: In addition to possessing intracellular vesicles, eukaryotic cells also produce extracellular microvesicles, ranging from 50 to 1000 nm in diameter that are released or shed into the microenvironment under physiological and pathological conditions. These membranous extracellular organelles include both exosomes (originating from internal vesicles of endosomes) and ectosomes (originating from direct budding/shedding of plasma membranes). Extracellular microvesicles contain cell-specific collections of proteins, glycoproteins, lipids, nucleic acids and other molecules. These vesicles play important roles in intercellular communication by acting as carrier for essential cell-specific information to target cells. Endothelial cells in the brain form the blood-brain barrier, a specialized interface between the blood and the brain that tightly controls traffic of nutrients and macromolecules between two compartments and interacts closely with other cells forming the neurovascular unit. Therefore, brain endothelial cell extracellular microvesicles could potentially play important roles in 'externalizing' brain-specific biomarkers into the blood stream during pathological conditions, in transcytosis of blood-borne molecules into the brain, and in cell-cell communication within the neurovascular unit.Methods: To study cell-specific molecular make-up and functions of brain endothelial cell exosomes, methods for isolation of extracellular microvesicles using mass spectrometry-compatible protocols and the characterization of their signature profiles using mass spectrometry -based proteomics were developed.Results: A total of 1179 proteins were identified in the isolated extracellular microvesicles from brain endothelial cells. The microvesicles were validated by identification of almost 60 known markers, including Alix, TSG101 and the tetraspanin proteins CD81 and CD9. The surface proteins on isolated microvesicles could potentially interact with both primary astrocytes and cortical neurons, as cell-cell communication vesicles. Finally, brain endothelial cell extracellular microvesicles were shown to contain several receptors previously shown to carry macromolecules across the blood brain barrier, including transferrin receptor, insulin receptor, LRPs, LDL and TMEM30A.Conclusions: The methods described here permit identification of the molecular signatures for brain endothelial cell-specific extracellular microvesicles under various biological conditions. In addition to being a potential source of useful biomarkers, these vesicles contain potentially novel receptors known for delivering molecules across the blood-brain barrier. © 2013 Haqqani et al.; licensee BioMed Central Ltd.
Keywords: ALIX protein; biological marker; CD81 antigen; CD9 antigen; insulin receptor; low density lipoprotein; low density lipoprotein receptor related protein; protein; tetraspanin; transferrin receptor; tumor susceptibility gene 101 protein; unclassified drug; article; blood brain barrier; brain endothelium cell; cell isolation; cell vacuole; endothelium cell; exosome; human; human cell; mass spectrometry; priority journal; protein analysis; protein function; protein localization; proteomics

A first look at the AURIGA-CALIFORNIA giant molecular cloud with Herschel and the CSO: Census of the young stellar objects and the dense gas - Harvey, P.M.; Fallscheer, C.; Ginsburg, A.; Terebey, S.; André, P.; Bourke, T.L.; Di Francesco, J.; Könyves, V.; Matthews, B.C.; Peterson, D.E. (The Astrophysical Journal, 2013)
We have mapped the Auriga/California molecular cloud with the Herschel PACS and SPIRE cameras and the Bolocam 1.1 mm camera on the Caltech Submillimeter Observatory with the eventual goal of quantifying the star formation and cloud structure in this giant molecular cloud (GMC) that is comparable in size and mass to the Orion GMC, but which appears to be forming far fewer stars. We have tabulated 60 compact 70/160 μm sources that are likely pre-main-sequence objects and correlated those with Spitzer and WISE mid-IR sources. At 1.1 mm, we find 18 cold, compact sources and discuss their properties. The most important result from this part of our study is that we find a modest number of additional compact young objects beyond those identified at shorter wavelengths with Spitzer. We also describe the dust column density and temperature structure derived from our photometric maps. The column density peaks at a few × 1022 cm-2 (NH2) and is distributed in a clear filamentary structure along which nearly all of the pre-main-sequence objects are found. We compare the young stellar object surface density to the gas column density and find a strong nonlinear correlation between them. The dust temperature in the densest parts of the filaments drops to ∼10 K from values ∼14-15 K in the low-density parts of the cloud. We also derive the cumulative mass fraction and probability density function of material in the cloud, which we compare with similar data on other star-forming clouds. © 2013. The American Astronomical Society. All rights reserved.

Characterization of a trifunctional glucosyltransferase essential for Moraxella catarrhalis lipooligosaccharide assembly - Luke-Marshall, N.R.; Edwards, K.J.; Sauberan, S.; St. Michael, F.; Vinogradov, E.V.; Cox, A.D.; Campagnari, A.A. (Glycobiology, 2013)
The human respiratory tract pathogen Moraxella catarrhalis expresses lipooligosaccharides (LOS), glycolipid surface moieties that are associated with enhanced colonization and virulence. Recent studies have delineated the major steps required for the biosynthesis and assembly of the M. catarrhalis LOS molecule. We previously demonstrated that the glucosyltransferase enzyme Lgt3 is responsible for the addition of at least one glucose (Glc) molecule, at the β-(1-4) position, to the inner core of the LOS molecule. Our data further suggested a potential multifunctional role for Lgt3 in LOS biosynthesis. The studies reported here demonstrate that the Lgt3 enzyme possesses two glycosyltransferase domains (A1 and A2) similar to that of other bifunctional glycosyltransferase enzymes involved in surface polysaccharide biosynthesis in Escherichia coli, Pasteurella multocida and Streptococcus pyogenes. Each Lgt3 domain contains a conserved DXD motif, shown to be involved in the catalytic activity of other glycosyltransferases. To determine the function of each domain, A1 (N-terminal), A2 (C-terminal) and double A1A2 site-directed DAD to AAA mutants were constructed and the resulting LOS phenotypes of these modified strains were analyzed. Our studies indicate that the Lgt3 N-terminal A1 catalytic domain is responsible for the addition of the first β-(1-3) Glc to the first Glc on the inner core. The C-terminal catalytic domain A2 then adds the β-(1-4) Glc and the β-(1-6) Glc, confirming the bifunctional nature of this domain. The results from these experiments demonstrate that Lgt3 is a novel, multifunctional transferase responsible for the addition of three Glcs with differing linkages onto the inner core of M. catarrhalis LOS. © 2013 The Author 2013.
Keywords: glucosyltransferase; lipooligosaccharide; amino terminal sequence; article; bacterial strain; biosynthesis; carbohydrate synthesis; carboxy terminal sequence; catalysis; Escherichia coli; Moraxella catarrhalis; nonhuman; nucleotide sequence; Pasteurella multocida; phenotype; priority journal; protein domain; protein motif; Streptococcus pyogenes

A modified protocol for retrograde cerebral perfusion: Magnetic resonance spectroscopy in pigs - Yang, Y.; Yang, L.; Sun, J.; Gruwel, M.L.; Deslauriers, R.; Ye, J. (European Journal of Cardio-thoracic Surgery, 2013)
Objectives: Retrograde cerebral perfusion (RCP) has been employed to protect the brain during cardiovascular surgery, requiring temporary hypothermic circulatory arrest (HCA). However, the protocol used for RCP remains to be modified if prolonged HCA is expected. The aim of this study was to determine the efficacy of a modified protocol for this purpose. Methods: After establishment of HCA at 15°C, 14 pigs were subjected to 90-min RCP using either the conventional protocol (i.e. alpha-stat strategy, 25-mmHg perfusion pressure and occluded inferior vena cava, Group I, n = 7) or the new protocol (i.e. pH-stat strategy, 40-mmHg perfusion pressure and unoccluded inferior vena cava, Group II, n = 7). After being rewarmed to 37°C, pigs were perfused for another 60 min. Phosphorus-31 magnetic resonance spectroscopy was used to track the changes of brain high-energy phosphates [i.e. adenosine triphosphate and phosphocreatine (PCr)] and intracellular pH (pHi). At the end, brain water content was measured. Results: During RCP, high-energy phosphates decreased in both groups, whereas adenosine triphosphate decreased much faster in Group I (10.4 ± 4.3 vs 30.4 ± 4.4% of the baseline, P = 0.007, 60-min RCP). After rewarming, the recovery of high-energy phosphates and pHi was much slower in Group I (PCr: 55.7 ± 9.1 vs 78.4 ± 5.1% of the baseline, P = 0.046; adenosine triphosphate: 26.6 ± 10.6 vs 64.8 ± 4.6% of the baseline, P = 0.007; pHi: 6.5 ± 0.4 vs 7.1 ± 0.1, P = 0.021 at 30-min normothermic perfusion after rewarming). Brain tissue water content was significantly higher in Group I (81.1 ± 0.4 vs 79.5 ± 0.4%, P = 0.016). Conclusions: Application of the modified RCP protocol significantly improved cerebral energy conservation during HCA and accelerated energy recovery after rewarming. © The Author 2012. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
Keywords: adenosine triphosphate; creatine phosphate; animal cell; animal experiment; animal tissue; article; brain level; brain perfusion; brain protection; cell pH; clinical effectiveness; clinical protocol; controlled study; deep hypothermic circulatory arrest; experimental pig; inferior cava vein; nonhuman; nuclear magnetic resonance spectroscopy; priority journal; retrograde cerebral perfusion; warming; water content; Adenosine Triphosphate; Animals; Body Temperature; Brain Chemistry; Cardiopulmonary Bypass; Hydrogen-Ion Concentration; Hypothermia, Induced; Magnetic Resonance Imaging; Perfusion Imaging; Phosphocreatine; Phosphorus Isotopes; Random Allocation; Swine

In Vivo detection of human TRPV6-rich tumors with anti-cancer peptides derived from soricidin - Bowen, Chris V.; DeBay, Drew; Ewart, Stephen H.; Gallant, Pamela; Gormley, Sean; Ilenchuk, T. Toney; Iqbal, Umar; Lutes, Tyler; Martina, Marzia; Mealing, Geoffrey; Merkley, Nadine; Sperker, Sandra; et al. (PLoS ONE, 2013)
Soricidin is a 54-amino acid peptide found in the paralytic venom of the northern short-tailed shrew (Blarina brevicauda) and has been found to inhibit the transient receptor potential of vallinoid type 6 (TRPV6) calcium channels. We report that two shorter peptides, SOR-C13 and SOR-C27, derived from the C-terminus of soricidin, are high-affinity antagonists of human TRPV6 channels that are up-regulated in a number of cancers. Herein, we report molecular imaging methods that demonstrate the in vivo diagnostic potential of SOR-C13 and SOR-C27 to target tumor sites in mice bearing ovarian or prostate tumors. Our results suggest that these novel peptides may provide an avenue to deliver diagnostic and therapeutic reagents directly to TRPV6-rich tumors and, as such, have potential applications for a range of carcinomas including ovarian, breast, thyroid, prostate and colon, as well as certain leukemia's and lymphomas.

Experimental investigation of load distribution in a composite girder bridge at elastic versus inelastic states - Razaqpur, A.G.; Shedid, M.; Nofal, M. (Engineering Structures, 2013)
Bridge design and evaluation involve the determination of the internal forces and moments that each bridge element must resist. In slab-on-girder bridges, the moment and shear caused by traffic loads are normally determined using load distribution factors. These factors are derived based on results of analytical models, numerical analyses, as well as actual loading tests, but there appears to be scant experimental data to gauge their accuracy, particularly beyond the elastic limit state. To address the scarcity of the experimental data and to understand how the distribution characteristics of concrete slab on steel girder composite bridges change with the advent of yielding and inelasticity, a 1/3 scale model of a hypothetical composite bridge was tested to failure in this study.Extensive measurements were taken during the test to allow better understanding of the response of slab-on-girder bridges as well as their live load distribution characteristics at all stages of loading up to failure. The experimentally determined distribution factors for the tested bridge model are compared with the calculated values based on the Canadian Highway Bridge Design Standard, and the code values are found to overestimate the maximum moment in the interior loaded girder by about 22% and 33% at the elastic and the inelastic states, respectively. © 2012 Elsevier Ltd.
Keywords: Bridge design; Bridge elements; Bridge model; Calculated values; Composite girder bridges; Distribution characteristics; Distribution factor; Elastic limit; Experimental investigations; Flexure; Highway bridge design; Internal forces; Live loads; Load distribution factor; Load distributions; Loading tests; Maximum moments; Reinforced; Scale models; Slab-on-girder bridge; Steel girder; Traffic loads; Beams and girders; Bridges; Composite bridges; Concrete slabs; Concretes; Numerical analysis; Steel; Loading; bridge; composite; concrete structure; design method; experimental study; failure analysis; flexure; loading; reinforced concrete; steel structure

In situ TEM study of stability of TaRhx diffusion barriers using a novel sample preparation method - Dalili, N.; Li, P.; Kupsta, M.; Liu, Q.; Ivey, D.G. (Micron, 2013)
The atomic diffusion mechanisms associated with metallurgical failure of TaRhx diffusion barriers for Cu metallizations were studied by in situ transmission electron microscopy (TEM). The issues related to in situ heating of focused ion beam (FIB) prepared cross-sectional TEM samples that contain Cu thin films are discussed. The Cu layer in Si/(13 nm)TaRhx /Cu stacks showed grain growth and formation of voids at temperatures exceeding 550 °C. For Si/(43 nm)TaRhx /Cu stacks, grain growth of Cu was delayed to higher temperatures, i.e., 700 °C, and void formation was not observed. Extensive surface diffusion of Cu, however, preceded bulk diffusion. Therefore, a 10 nm film of electron beam evaporated C was deposited on both sides of the TEM lamellae to limit surface diffusion. This processing technique allowed for direct observation of atomic diffusion and reaction mechanisms across the TaRhx interface. Failure occurred by nucleation of orthorhombic RhSi particles at the Si/TaRhx interface. Subsequently, the barrier at areas adjacent to RhSi particles was depleted in Rh. This created lower density areas in the barrier, which facilitated diffusion of Cu to the Si substrate to form Cu3Si. The morphology of an in situ annealed lamella was compared with an ex situ bulk annealed sample, which showed similar reaction morphology. The sample preparation method developed in this study successfully prevented surface diffusion/delamination of the Cu layer and can be employed to understand the metallurgical failure of other potential diffusion barriers. © 2013 Elsevier Ltd. All rights reserved.