Debris disks and multiplicity within the 75pc volume-limited A-Star (VAST) survey - De Rosa, R. J.; Smith, B.; Bulger, J.; Patience, J.; Marois, C.; Song, I.; Macintosh, B.; Graham, J.; Doyon, R.; Bessell, M. (Exploring the Formation and Evolution of Planetary Systems: Proceedings of the 299th Symposium of the International Astronomical Union held in Victoria, Canada, June 2 - 7, 2013, 2014)
We present the preliminary findings of an investigation of the multiplicity of debris disk stars identified within our Volume-limited A-star (VAST) multiplicity survey. Previous studies have produced conflicting results regarding the multiplicity fraction of debris disk-hosting stars compared with non-excess stars. By combining our large-scale volume-limited AO survey of A-type stars with the all-sky WISE catalogue, we have investigated the frequency of binary companions to a large sample of A-type stars with and without measured 22μm excess. The results of this study will allow for a greater understanding of the interaction between a companion star and a circumstellar debris disk, informing future study into the formation and stability of planetary-mass companions within binary systems.
Keywords: stars: circumstellar matter; stars: binaries: visual; stars: early-type

Where do solar filaments form? - Mackay, Duncan H.; Gaizauskas, Vytautas (Victor); Yeates, Anthony R. (Nature of Prominences and their Role in Space Weather, 2014)
In the present study, we consider where large, stable solar filaments form relative to underlying magnetic polarities. We find that 92% of all large stable filaments form in magnetic configurations involving the interaction of two or more bipoles. Only 7% form above the Polarity Inversion Line (PIL) of a single bipole. This indicates that a key element in the formation of largescale stable filaments is the convergence of magnetic flux, resulting in either flux cancellation or coronal reconnection.

Optical racetrack resonator transduction of nanomechanical cantilevers - Sauer, V. T. K.; Diao, Z.; Freeman, M. R.; Hiebert, W. K. (Nanotechnology, 2014)
Optomechanical transduction has demonstrated its supremacy in probing nanomechanical displacements. In order to apply nano-optomechanical systems (NOMS) as force and mass sensors, knowledge about the transduction responsivity (i.e. the change in measured optical transmission with nanomechanical displacement) and its tradeoffs with system design is paramount. We compare the measured responsivities of NOMS devices with varying length, optomechanical coupling strength gom, and optical cavity properties. Cantilever beams 1.5 to 5 μm long are fabricated 70 to 160 nm from a racetrack resonator optical cavity and their thermomechanical (TM) noise signals are measured. We derive a generic expression for the transduction responsivity of the NOMS in terms of optical and mechanical system parameters such as finesse, optomechanical coupling constant, and interaction length. The form of the expression holds direct insight as to how these parameters affect the responsivity. With this expression, we obtain the optomechanical coupling constants using only measurements of the TM noise power spectra and optical cavity transmission slopes. All optical pump/probe operation is also demonstrated in our side-coupled cantilever-racetrack NOMS. Finally, to assess potential operation in a gas sensing environment, the TM noise signal of a device is measured at atmospheric pressure.

A simple and sensitive biosensor for rapid detection of nanoparticles in water - Bhomkar, Prasanna; Goss, Greg; Wishart, David S. (Journal of Nanoparticle Research, 2014)
Advances in nanoscience have led to a greater use of engineered nanoparticles (ENPs) in numerous applications. Due to their small size and unique surface properties, ENPs have many desirable features. However, they also interact with living cells in potentially undesirable manners highlighting the need to develop improved detection systems to manage risks associated with their accidental occupational exposure or environmental release. However, the routine detection of ENPs has not yet been demonstrated, especially for aquatic environments. Using standard protein engineering techniques, we generated a protein-based biosensor that can sensitively detect negatively charged ENPs in aquatic matrices. In particular, we genetically engineered a green fluorescent protein with a poly-lysine tag (His-GFP-LYS) to facilitate its electrostatic interaction with commercially available negatively charged NPs. These 5-6-nm-sized NPs have metallic cores comprising gold, iron oxide, cerium oxide, and zinc oxide and are stabilized via poly-acrylic acid (PAA) coating. The interaction between the recombinant positively charged GFP and the PAA coating of the negatively charged NPs resulted in visually observable turbidity changes that were quantified using a portable spectrophotometer (NANODROP). These interactions were confirmed using dynamic light scattering and visualized using agarose native gel electrophoresis. This simple and portable system could detect ENPs resuspended in pure aqueous buffer (0.08 mg/L) and those resuspended in environmental matrices, such as pond water (0.6 mg/L). This detection system also sensed ENPs in the presence of moderate concentrations of natural organic matter that is ubiquitously present in surface waters. These results suggest that this biosensor system could be used for the routine, portable, and affordable detection of negatively-charged ENPs under environmentally relevant aquatic conditions. © 2014 Her Majesty the Queen in Rights of Canada .

The Next Generation Virgo Cluster Survey-Infrared (NGVS-IR). I. A new near-ultraviolet, optical, and near-infrared globular cluster selection tool - Muñoz, R.P.; Puzia, T.H.; Lançon, A.; Peng, E.W.; Côté, P.; Ferrarese, L.; Blakeslee, J.P.; Mei, S.; Cuillandre, J.-C.; Hudelot, P.; Courteau, S.; Duc, P.-A.; et al. (Astrophysical Journal, Supplement Series, 2014)
The NGVS-IR project (Next Generation Virgo Cluster Survey-Infrared) is a contiguous, near-infrared imaging survey of the Virgo cluster of galaxies. It complements the optical wide-field survey of Virgo (NGVS). In its current state, NGVS-IR consists of Ks -band imaging of 4 deg2 centered on M87 and J- and Ks -band imaging of 16 deg2 covering the region between M49 and M87. We present observations of the central 4 deg2 centered on Virgo's core region. The data were acquired with WIRCam on the Canada-France-Hawaii Telescope, and the total integration time was 41 hr distributed over 34 contiguous tiles. A survey-specific strategy was designed to account for extended galaxies while still measuring accurate sky brightness within the survey area. The average 5σ limiting magnitude is Ks = 24.4 AB mag, and the 50% completeness limit is Ks = 23.75 AB mag for point-source detections, when using only images with better than 0.″7 seeing (median seeing 0.″54). Star clusters are marginally resolved in these image stacks, and Virgo galaxies with AB mag arcsec-2 are detected. Combining the Ks data with optical and ultraviolet data, we build the uiKs color-color diagram, which allows a very clean color-based selection of globular clusters in Virgo. This diagnostic plot will provide reliable globular cluster candidates for spectroscopic follow-up campaigns, needed to continue the exploration of Virgo's photometric and kinematic substructures, and will help the design of future searches for globular clusters in extragalactic systems. We show that the new uiKs diagram displays significantly clearer substructure in the distribution of stars, globular clusters, and galaxies than the gzKs diagram - the NGVS + NGVS-IR equivalent of the BzK diagram that is widely used in cosmological surveys. Equipped with this powerful new tool, future NGVS-IR investigations based on the uiKs diagram will address the mapping and analysis of extended structures and compact stellar systems in and around Virgo galaxies. © 2014. The American Astronomical Society. All rights reserved..

Release characteristics of selected carbon nanotube polymer composites - Kingston, C.; Zepp, R.; Andrady, A.; Boverhof, D.; Fehir, R.; Hawkins, D.; Roberts, J.; Sayre, P.; Shelton, B.; Sultan, Y.; Vejins, V.; Wohlleben, W. (Carbon, 2014)
Multi-walled carbon nanotubes (MWCNTs) are commonly used in polymer formulations to improve strength, conductivity, and other attributes. A developing concern is the potential for carbon nanotube polymer nanocomposites to release nanoparticles into the environment as the polymer matrix degrades or is mechanically stressed. Here, we review characteristics related to release potential of five sets of polymer systems: epoxy, polyamide, polyurethane, polyethylene, and polycarbonate. Our review includes consideration of general characteristics and use of the polymer (as related to potential MWCNT release) and its MWCNT composites; general potential for nanomaterial release (particularly MWCNTs) due to degradation and mechanical stresses during use; and potential effects of stabilizers and plasticizers on polymer degradation. We examine UV degradation, temperature extremes, acid-base catalysis, and stresses such as sanding. Based on a high-level summary of the characteristics considered, the potential for release of MWCNT with typical, intended consumer use is expected to be low. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Acid-base catalysis; Carbon nanotube-polymer composites; Nanomaterial release; Polymer degradation; Polymer formulation; Polymer nanocomposite; Release characteristics; Temperature extremes; Multiwalled carbon nanotubes (MWCN); Nanocomposites; Solvents; Stresses

Structure elucidation of capsular polysaccharides from Streptococcus pneumoniae serotype 33C, 33D, and revised structure of serotype 33B - Lin, F.L.; Vinogradov, E.; Deng, C.; Zeller, S.; Phelan, L.; Green, B.A.; Jansen, K.U.; Pavliak, V. (Carbohydrate Research, 2014)
We report herein the previously unknown structures of the pneumococcal capsular polysaccharides serotype 33C and 33D, and a revised structure of serotype 33B. The syntenic pair 33B/33D has nearly identical polysaccharide repeat units with the exception of one sugar residue (→2-α-Glcp in 33B and →2-α-Galp in 33D). Serotype 33C is structurally more similar to 33B/33D than 33A/33F, in that it also possesses a backbone ribitol-phosphate group and a →3-β-GalpNAc residue, both of which are absent in the repeat units of 33A/33F. Serotype 33C is notably different from all other serogroup 33 polysaccharides, as there is no →3-β-Glcp residue and the location of the O-acetylation of the →5-β-Galf residue (O-6) differs from the other serogroup 33 polysaccharides (O-2). This completes the structural assignments of polysaccharides within serogroup 33 and provides a framework for understanding the recognition of epitopes by serogroup 33 typing sera based on observed cross-reactivities reported in the literature. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Capsular polysaccharides; Cross reactivity; Serogroup 33; Serotypes; Streptococcus pneumoniae; Structural assignments; Structure elucidation; Sugar residues; Acetylation; Polysaccharides; bacterial polysaccharide; epitope; galactose; glucose; monosaccharide; n acetylgalactosamine; phosphate; pneumococcal capsular polysaccharide; ribitol; ribitol phosphate; unclassified drug; acetylation; article; bacterial capsule; carbohydrate analysis; controlled study; cross reaction; gas chromatography; heteronuclear single quantum coherence; linkage analysis; mass spectrometry; methylation; nonhuman; nuclear magnetic resonance spectroscopy; priority journal; serotype; Streptococcus pneumoniae; Streptococcus pneumoniae

Tribological characterization of plasma-sprayed CoNiCrAlY-BN abradable coatings - Irissou, É.; Dadouche, A.; Lima, R. S. (Journal of Thermal Spray Technology, 2014)
The processing conditions, microstructural and tribological characterizations of plasma-sprayed CoNiCrAlY-BN high temperature abradable coatings are reported in this manuscript. Plasma spray torch parameters were varied to produce a set of abradable coatings exhibiting a broad range of porosity levels (34-62%) and superficial Rockwell hardness values (0-78 HR15Y). Abradability tests have been performed using an abradable-seal test rig, capable of simulating operational wear at different rotor speeds and seal incursion rates (SIRs). These tests allowed determining the rubbing forces and quantifying the blade and seal wear characteristics for slow and fast SIRs. Erosion wear performance and ASTM C633 coating adhesion strength test results are also reported. For optimal abradability performance, it is shown that coating hardness needs to be lower than 70 and 50 HR15Y for slow and fast blade incursion rate conditions, respectively. It is shown that the erosion wear performance, as well as, the coating cohesive strength is a function of the coating hardness. The current results allow defining the coating specifications in terms of hardness and porosity for targeted applications. This article is an invited paper selected from presentations at the 2013 International Thermal Spray Conference, held May 13-15, 2013, in Busan, South Korea, and has been expanded from the original presentation.
Keywords: Abradable coating; Adhesive strength; Atmospheric plasma spray; Erosion resistance; MCrAlY; Coatings; Gas turbines; Hardness; Plasma jets; Porosity; Tribology; Plasma spraying

Experiments with three approaches to recognizing lexical entailment - Turney, P. D.; Mohammad, S. M. (Natural Language Engineering, 2014)
Inference in natural language often involves recognizing lexical entailment (RLE), that is, identifying whether one word entails another. For example, buy entails own. Two general strategies for RLE have been proposed: One strategy is to manually construct an asymmetric similarity measure for context vectors (directional similarity) and another is to treat RLE as a problem of learning to recognize semantic relations using supervised machine-learning techniques (relation classification). In this paper, we experiment with two recent state-of-the-art representatives of the two general strategies. The first approach is an asymmetric similarity measure (an instance of the directional similarity strategy), designed to capture the degree to which the contexts of a word, a, form a subset of the contexts of another word, b. The second approach (an instance of the relation classification strategy) represents a word pair, a: b, with a feature vector that is the concatenation of the context vectors of a and b, and then applies supervised learning to a training set of labeled feature vectors. In addition, we introduce a third approach that is a new instance of the relation classification strategy. The third approach represents a word pair, a: b, with a feature vector in which the features are the differences in the similarities of a and b to a set of reference words. All three approaches use vector space models of semantics, based on word-context matrices. We perform an extensive evaluation of the three approaches using three different datasets. The proposed new approach (similarity differences) performs significantly better than the other two approaches on some datasets and there is no dataset for which it is significantly worse. Along the way, we address some of the concerns raised in past research, regarding the treatment of RLE as a problem of semantic relation classification, and we suggest, it is beneficial to make connections between the research in lexical entailment and the research in semantic relation classification. Copyright © Her Majesty the Queen in Right of Canada, as represented by the National Research Council Canada 2014.

Estimation of the bioaccumulation potential of a nonchlorinated bisphenol and an ionogenic xanthene dye to Eisenia andrei in field-collected soils, in conjunction with predictive in silico profiling - Princz, J.; Bonnell, M.; Ritchie, E.; Velicogna, J.; Robidoux, P.-Y.; Scroggins, R. (Environmental Toxicology and Chemistry, 2014)
In silico-based model predictions, originating from structural and mechanistic (e.g., transport, bioavailability, reactivity, and binding potential) profiling, were compared against laboratory-derived data to estimate the bioaccumulation potential in earthworms of 2 organic substances (1 neutral, 1 ionogenic) known to primarily partition to soil. Two compounds representative of specific classes of chemicals were evaluated: a nonchlorinated bisphenol containing an -OH group (4,4′-methylenebis[2,6-di-tert-butylphenol] [Binox]), and an ionogenic xanthene dye (2′,4′,5′,7′-tetrabromo-4,5,6,7-tetrachloro-3′,6′-dihydroxy-, disodium salt [Phloxine B]). Soil bioaccumulation studies were conducted using Eisenia andrei and 2 field-collected soils (a clay loam and a sandy soil). In general, the in silico structural and mechanistic profiling was consistent with the observed soil bioaccumulation tests. Binox did not bioaccumulate to a significant extent in E. andrei in either soil type; however, Phloxine B not only accumulated within tissue, but was not depurated from the earthworms during the course of the elimination phase. Structural and mechanistic profiling demonstrated the binding and reactivity potential of Phloxine B; this would not be accounted for using traditional bioaccumulation metrics, which are founded on passive-based diffusion mechanisms. This illustrates the importance of profiling for reactive ionogenic substances; even limited bioavailability combined with reactivity can result in exposures to a hazardous substance not predictable by traditional in silico modeling methods.
Keywords: Bioaccumulation; Bisphenol; Earthworm; Soil; Xanthene

Improved Zn/Zn(II) redox kinetics, reversibility and cyclability in 1-ethyl-3-methylimmidazolium dicyanamide with water and dimethyl sulfoxide added - Xu, M.; Ivey, D.G.; Qu, W.; Xie, Z. (Journal of Power Sources, 2014)
Diluents composed of H2O and dimethyl sulfoxide (DMSO) were added to 1-ethyl-3-methylimmidazolium dicyanamide (EMI-DCA), yielding an electrolyte system that is potentially applicable for Zn-air batteries. H 2O is critical for enhancing both the electrolyte conductivity and Zn/Zn(II) redox kinetics, but impairs Zn/Zn(II) redox reversibility and cyclability. DMSO has the ability to stabilize the electrolyte from H 2O decomposition and is beneficial for maintaining Zn/Zn(II) redox reversibility and cyclability. Improved Zn/Zn(II) redox kinetics and reversibility, together with good cyclability up to 200 cycles, was achieved in EMI-DCA + H2O + DMSO in a mole ratio of 1:1.1:2.3. © 2013 Elsevier B.V. All rights reserved.
Keywords: Battery electrolyte; Dicyanamide; Diluents; Dimethyl sulfoxide (DMSO); Electrolyte conductivity; Electrolyte systems; Redox kinetics; Room temperature ionic liquids; Dimethyl sulfoxide; Electrolytes; Ionic liquids; Kinetics; Redox reactions; Organic solvents

Neuroprotective Effects of GDNF-expressing Human Amniotic Fluid Cells - Jezierski, A.; Rennie, K.; Zurakowski, B.; Ribecco-Lutkiewicz, M.; Haukenfrers, J.; Ajji, A.; Gruslin, A.; Sikorska, M.; Bani-Yaghoub, M. (Stem Cell Reviews and Reports, 2014)
Brain injury continues to be one of the leading causes of disability worldwide. Despite decades of research, there is currently no pharmacologically effective treatment for preventing neuronal loss and repairing the brain. As a result, novel therapeutic approaches, such as cell-based therapies, are being actively pursued to repair tissue damage and restore neurological function after injury. In this study, we examined the neuroprotective potential of amniotic fluid (AF) single cell clones, engineered to secrete glial cell derived neurotrophic factor (AF-GDNF), both in vitro and in a surgically induced model of brain injury. Our results show that pre-treatment with GDNF significantly increases cell survival in cultures of AF cells or cortical neurons exposed to hydrogen peroxide. Since improving the efficacy of cell transplantation depends on enhanced graft cell survival, we investigated whether AF-GDNF cells seeded on polyglycolic acid (PGA) scaffolds could enhance graft survival following implantation into the lesion cavity. Encouragingly, the AF-GDNF cells survived longer than control AF cells in serum-free conditions and continued to secrete GDNF both in vitro and following implantation into the injured motor cortex. AF-GDNF implantation in the acute period following injury was sufficient to activate the MAPK/ERK signaling pathway in host neural cells in the peri-lesion area, potentially boosting endogenous neuroprotective pathways. These results were complemented with promising trends in beam walk tasks in AF-GDNF/PGA animals during the 7 day timeframe. Further investigation is required to determine whether significant behavioural improvement can be achieved at a longer timeframe. © 2014 Crown Copyright as represented by: Danica Stanimirovic.

Sub-femtomole detection of 16s rRNA from Legionella pneumophila using surface plasmon resonance imaging - Foudeh, A.M.; Daoud, J.T.; Faucher, S.P.; Veres, T.; Tabrizian, M. (Biosensors and Bioelectronics, 2014)
Legionellosis has been and continues to be a life-threatening disease worldwide, even in developed countries. Given the severity and unpredictability of Legionellosis outbreaks, developing a rapid, highly specific, and sensitive detection method is thus of great pertinence. In this paper, we demonstrate that sub-femtomole levels of 16s rRNA from pathogenic Legionella pneumophila can be timely and effectively detected using an appropriate designed capture, detector probes, and a QD SPRi signal amplification strategy. To achieve specific and sensitive detection, optimal hybridization conditions and parameters were implemented. Among these parameters, fragmentation of the 16s rRNA and further signal amplification by QDs were found to be the main parameters contributing to signal enhancement. The appropriate design of the detector probes also increased the sensitivity of the detection system, mainly due to secondary structure of 16s rRNA. The use of 16s rRNA from L. pneumophila allowed for the detection of metabolically active pathogens with high sensitivity. Detection of 16s rRNA in solutions as diluted as 1. pM at 450. μL (0.45. femtomole) was achieved in less than 3. h, making our approach suitable for the direct, timely, and effective detection of L. pneumophila within man-made water systems. © 2013 Elsevier B.V.
Keywords: 16S rRNA; Hybridization; Legionella pneumophila; Pathogen detection; Quantum dot; Surface plasmon resonance imaging; Bioassay; Pathogens; Plasmons; Signal processing; Surface plasmon resonance; RNA; RNA 16S; article; electron capture detection; fragmentation reaction; Legionella pneumophila; legionnaire disease; limit of detection; nonhuman; RNA sequence; sensitivity and specificity; surface plasmon resonance

Alignment in star-debris disc systems seen by Herschel - Greaves, J.S.; Kennedy, G.M.; Thureau, N.; Eiroa, C.; Marshall, J.P.; Maldonado, J.; Matthews, B.C.; Olofsson, G.; Barlow, M.J.; Moro-Mart́in, A.; Sibthorpe, B.; Absil, O.; et al. (Monthly Notices of the Royal Astronomical Society: Letters, 2014)
Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral types A-M where the stellar inclination is known and can be compared to that of the spatially resolved dust belts. The discs are found to be well aligned with the stellar equators, as in the case of the Sun's Kuiper belt, and unlike many close-in planets seen in transit surveys. The ensemble of stars here can be fitted with a star-disc tilt of ≲10°. These results suggest that proposed mechanisms for tilting the star or disc in fact operate rarely. A few systems also host imaged planets, whose orbits at tens of au are aligned with the debris discs, contrary to what might be expected in models where external perturbers induce tilts. © 2013 The Authors.

The effect of displacement field on bending, buckling, and vibration of cross-ply circular cylindrical shells - Shadmehri, F.; Hoa, S.; Hojjati, M. (Mechanics of Advanced Materials and Structures, 2014)
The effect of assumed displacement field is investigated on the bending, buckling, and natural frequencies of cross-ply circular cylindrical shells using first-order shear deformation theory through an analytical solution. Linear strain-displacement relation is assumed. The governing equations are derived from Hamilton's principle. Assuming Levy-type solution, the governing equations are then converted to ordinary differential equations and changed to state-space form introducing ten unknown variables and solved for displacements. Different lamination sequences, including symmetric and asymmetric laminate, are studied and compared. The effect of various boundary conditions (i.e., clamped, simply supported, and free edge), radius-to-thickness, and radius-to-length ratio on the displacement of mid-surface is investigated. © 2014 Taylor and Francis Group, LLC.
Keywords: Circular cylindrical shells; Cylindrical shell; First-order shear deformation theory; Laminated composite shell; Radius-to-length ratio; Strain-displacement relation; Various boundary conditions; vibration; Bending (forming); Buckling; Cylinders (shapes); Laminated composites; Ordinary differential equations; State space methods; Shells (structures)

A new composite material-low-carbon Stellite alloy reinforced with nickel-coated carbon fibers - Khoddamzadeh, A.; Liu, R.; Liang, M.; Yang, Q. (Journal of Composite Materials, 2014)
A group of nickel-coated carbon fiber reinforced Stellite 25 composites are produced using the hot isostatic pressing technique. The focus of this research is on obviating the problems related to the presence of carbides in Stellite alloys by substituting carbides as the main strengthening agent in Stellite alloys with nickel-coated carbon fibers. The principal reason for selecting Stellite 25 is because of its low carbon content and thereby relatively carbide free microstructure. The nickel coating is intended to eliminate any chance of carbide formation due to the possible reaction between carbon fibers and the matrix alloying additions. The tribomechanical and corrosion properties of the composites are characterized. The results show that the composites exhibit better corrosion resistance than medium-carbon Stellite alloys. The addition of carbon fibers into Stellite 25 improves its hardness and tribological properties. The wear rates of the composites are lower than that of medium-carbon Stellite alloys and comparable with that of high-carbon Stellites. © The Author(s) 2012.
Keywords: Alloying additions; Carbide formation; Corrosion property; Nickel-coated carbon fiber; Stellite alloy; Strengthening agents; Tribological properties; Wear rates; Carbides; Carbon fibers; Corrosion; Corrosion resistance; Friction; Hardness; Hot isostatic pressing; Metallic matrix composites; Nickel coatings; Powder metallurgy; Sintering; Superalloys; Wear of materials; Stellite

Exhaustive docking and solvated interaction energy scoring: lessons learned from the SAMPL4 challenge - Hogues, H.; Sulea, T.; Purisima, E.O. (Journal of Computer-Aided Molecular Design, 2014)
We continued prospective assessments of the Wilma-solvated interaction energy (SIE) platform for pose prediction, binding affinity prediction, and virtual screening on the challenging SAMPL4 data sets including the HIV-integrase inhibitor and two host-guest systems. New features of the docking algorithm and scoring function are tested here prospectively for the first time. Wilma-SIE provides good correlations with actual binding affinities over a wide range of binding affinities that includes strong binders as in the case of SAMPL4 host-guest systems. Absolute binding affinities are also reproduced with appropriate training of the scoring function on available data sets or from comparative estimation of the change in target's vibrational entropy. Even when binding modes are known, SIE predictions lack correlation with experimental affinities within dynamic ranges below 2 kcal/mol as in the case of HIV-integrase ligands, but they correctly signaled the narrowness of the dynamic range. Using a common protein structure for all ligands can reduce the noise, while incorporating a more sophisticated solvation treatment improves absolute predictions. The HIV-integrase virtual screening data set consists of promiscuous weak binders with relatively high flexibility and thus it falls outside of the applicability domain of the Wilma-SIE docking platform. Despite these difficulties, unbiased docking around three known binding sites of the enzyme resulted in over a third of ligands being docked within 2 Å from their actual poses and over half of the ligands docked in the correct site, leading to better-than-random virtual screening results. © 2014 Her Majesty the Queen in Right of Canada.

Assessment of antimicrobial (Host Defense) peptides as anti-cancer agents - Douglas, S.; Hoskin, D.W.; Hilchie, A.L. (Methods in Molecular Biology, 2014)
Cationic antimicrobial (host defense) peptides (CAPs) are able to kill microorganisms and cancer cells, leading to their consideration as novel candidate therapeutic agents in human medicine. CAPs can physically associate with anionic membrane structures, such as those found on cancer cells, causing pore formation, intracellular disturbances, and leakage of cell contents. In contrast, normal cells are less negatively-charged and are typically not susceptible to CAP-mediated cell death. Because the interaction of CAPs with cells is based on charge properties rather than cell proliferation, both rapidly dividing and quiescent cancer cells, as well as multidrug-resistant cancer cells, are targeted by CAPs, making CAPS potentially valuable as anti-cancer agents. CAPs often exist as families of peptides with slightly different amino acid sequences. In addition, libraries of synthetic peptide variants based on naturally occurring CAP templates can be generated in order to improve upon their action. High-throughput screens are needed to quickly and efficiently assess the suitability of each CAP variant. Here we present the methods for assessing CAP-mediated cytotoxicity against cancer cells (suspension and adherent) and untransformed cells (measured using the tritiated thymidine-release or MTT assay), and for discriminating between cell death caused by necrosis (measured using lactate dehydrogenase-or 51Cr- release assays), or apoptosis and necrosis (single-stranded DNA content measured by flow cytometry). In addition the clonogenic assay, which assesses the ability of single transformed cells to multiply and produce colonies, is described. © 2014 Springer Science+Business Media, LLC.
Keywords: antimicrobial cationic peptide; antineoplastic agent; chromium 51; lactate dehydrogenase; single stranded DNA; thymidine; adherent cell; apoptosis; cancer cell; cell death; cell suspension; cell transformation; clonogenic assay; cytotoxicity; DNA content; flow cytometry; host resistance; necrosis

Lipopolysaccharide glycotyping of clarithromycin-resistant and clarithromycin-susceptible Canadian isolates of Helicobacter pylori - Altman, E.; Harrison, B.A.; Chandan, V.; Slinger, R. (Canadian Journal of Microbiology, 2014)
Lipopolysaccharide (LPS) of Helicobacter pylori exhibits several unique structures, such as Lewis (Le) antigens, α-1, 6-glucan, and DD-heptan. To investigate the relationship between LPS structure and resistance to clarithromycin, 41 Canadian isolates of H. pylori were characterized by whole-cell ELISA (enzyme-linked immunosorbent assay), sugar analysis, immunoblotting, and indirect immunofluorescence. The expression of type 2 Lewis X and (or) Lewis Y antigens was detected in 22 of 23 (95.7%) clarithromycin-resistant and in 14 of 18 (77.7%) clarithromycin-susceptible H. pylori strains (P < 0.05), and 8 isolates co-expressed type 1 and type 2 Le antigens (8/41, 19.5%). A significantly higher frequency of α-1, 6-glucan (P < 0.01) was detected in clarithromycin-resistant strains than in clarithromycin-susceptible strains (19/23 (82.6%) versus 11/18 (61.1%)). Sugar analysis of selected α-1, 6-glucan-positive H. pylori strains confirmed that they frequently contained elevated amounts of DD-heptose. Clarithromycin-resistant isolates were also characterized by low expression levels or absence of CagA (17/23, 73.9%). Indirect immunofluorescence studies carried out on selected H. pylori strains with rabbit immune sera specific for α-1, 6-glucan confirmed broad recognition of α-1, 6-glucan epitope. The binding was not affected by LPS glycotype of H. pylori isolates examined nor by their CagA status or resistance to clarithromycin. These findings suggest α-1, 6-glucan as a potential vaccine target, especially in an era of increasing clarithromycin resistance in H. pylori.

BI CVn - A spotted, overcontact, type-W eclipsing binary - Nelson, R.H.; Şenavci, H.V.; Baştürk, Ö.; Bahar, E. (New Astronomy, 2014)
We present photometric and spectroscopic observations of the eclipsing binary system BI CVn. Wilson-Devinney analysis of its light and radial velocity curves showed that the system is a W-subtype overcontact W-UMa type binary. We computed the absolute physical parameters of the system based on a mass ratio spectroscopically determined in this study. Though the orbital period had changed somehow in the past, it has remained constant for a long time since March 1999, contradicting the previous interpretations suggesting a cyclic variation superimposed on a quadratic change. © 2013 Elsevier B.V. All rights reserved.

Effects of multiple scattering on radiative properties of soot fractal aggregates - Yon, J.; Liu, F.; Bescond, A.; Caumont-Prim, C.; Rozé, C.; Ouf, F.-X.; Coppalle, A. (Journal of Quantitative Spectroscopy and Radiative Transfer, 2014)
The in situ optical characterization of smokes composed of soot particles relies on light extinction, angular static light scattering (SLS), or laser induced incandescence (LII). These measurements are usually interpreted by using the Rayleigh-Debye-Gans theory for Fractal Aggregates (RDG-FA). RDG-FA is simple to use but it completely neglects the impact of multiple scattering (MS) within soot aggregates. In this paper, based on a scaling approach that takes into account MS effects, an extended form of the RDG-FA theory is proposed in order to take into account these effects. The parameters of this extended theory and their dependency on the number of primary sphere inside the aggregate (1 < N p < 1006) and on the wavelength (266 nm < λ < 1064 nm) are evaluated thanks to rigorous calculations based on discrete dipole approximation (DDA) and generalized multi-sphere Mie-solution (GMM) calculations. This study shows that size determination by SLS is not distorted by MS effect. On the contrary, it is shown that fractal dimension can be misinterpreted by light scattering experiments, especially at short wavelengths. MS effects should be taken into account for the interpretation of absorption measurements that are involved in LII or extinction measurements. © 2013 Elsevier Ltd.
Keywords: Absorption measurements; Discrete dipole approximation; Extinction measurements; FRactal aggregate; GMM; Laser induced incandescence; Optical characterization; RDG-FA; Digital differential analyzers; Fractal dimension; Light scattering; Multiple scattering; Soot; Aggregates; fractal analysis; light scattering; measurement method; radiative transfer; soot

Toward single-step anodic fabrication of monodisperse TiO2 nanotube arrays on non-native substrates - Farsinezhad, S.; Dalrymple, A.N.; Shankar, K. (Physica Status Solidi (A) Applications and Materials Science, 2014)
Shape irregularity and size dispersion exhibited by TiO2 nanotube arrays (TNAs) is a disadvantage for size-selective applications such as flow-through membranes, cell differentiation and drug delivery, and for photonic applications such as photonic crystals and metallodielectric metamaterials, where size and shape dispersity are sources of defects and scattering. We show that achieving extremely smooth Ti films is more critical than a large Ti grain size in attaining highly ordered nanotube arrays with minimal dispersity in shape and size, and obtain the insight that uniform pore nucleation is determinative of the quality of the nanostructures that result following electrochemical anodization. TiO2 nanotubes formed by anodization of highly smooth Ti films on single crystal silicon wafers in electrolytes with high water concentrations had only circular pores with a narrow dispersion of pore diameters, and exhibited uniform cross-sections along the tube-axis. Pattern order was evaluated using 2D-FFT analysis. TiO2 nanotubes on Si wafers with a (a) narrow and (b) wide dispersion in shape and size. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Herschel observations of the HR 8799 disk - Matthews, B.C.; Kennedy, G.; Sibthorpe, B.; Booth, M.; Broekhoven-Fiene, H.; Wyatt, M.; Macintosh, B.; Marois, C. (Exploring the Formation and Evolution of Planetary Systems, 2014)
The HR 8799 four-planet host is known to host a multi-component disk from Spitzer observations. We have obtained Herschel† observations of the disk which provide increased sensitivity and resolution of its outer components: the planetesimal belt and halo. We find that the two components cannot be discerned from the spectral energy distribution alone, but require resolved images to independently identify them. In the resolved images, the halo stands out for its steep radial profile and large radial extent to 2000 AU, a factor of two larger than was estimated from Spitzer data. Copyright © 2013, International Astronomical Union.
Keywords: stars: individual (HR 8799); stars: circumstellar matter; planetary systems

Dimyristoyl phosphatidylcholine: A remarkable exception to α-tocopherol's membrane presence - Marquardt, D.; Williams, J.A.; Kinnun, J.J.; Kučerka, N.; Atkinson, J.; Wassall, S.R.; Katsaras, J.; Harroun, T.A. (Journal of the American Chemical Society, 2014)
Using data obtained from different physical techniques (i.e., neutron diffraction, NMR and UV spectroscopy), we present evidence which explains some of the conflicting and inexplicable data found in the literature regarding α-tocopherol's (aToc's) behavior in dimyristoyl phosphatidylcholine (di-14:0PC) bilayers. Without exception, the data point to aToc's active chromanol moiety residing deep in the hydrophobic core of di-14:0PC bilayers, a location that is in stark contrast to aToc's location in other PC bilayers. Our result is a clear example of the importance of lipid species diversity in biological membranes and importantly, it suggests that measurements of aToc's oxidation kinetics, and its associated byproducts observed in di-14:0PC bilayers, should be reexamined, this time taking into account its noncanonical location in this bilayer. © 2013 American Chemical Society.

On the ν12 band of C6D6 at 2289 cm -1 - Rezaei, M.; McKellar, A.R.W.; Moazzen-Ahmadi, N. (Journal of Molecular Spectroscopy, 2014)
New supersonic jet spectra (T ≈ 2.5 K) show that the analysis by Plíva et al. (1994) of the ν12 (C-D stretch) band of C 6D6 near 2289 cm-1 is partly incorrect. In particular, the ν2 + ν13 combination band, which is strongly coupled to ν12 by a Fermi interaction, is centered at 2275.878 cm-1, which is 1.22 cm-1 higher than previously determined. © 2013 Elsevier Inc. All rights reserved.
Keywords: Combination bands; Fermi interaction; Infrared spectrum; Supersonic jets; Benzene; Molecular spectroscopy; Physical chemistry; Spectroscopy; Supersonic aerodynamics

Structural basis for antibody recognition in the receptorbinding domains of toxins a and B from clostridium difficile - Murase, T.; Eugenio, L.; Schorr, M.; Hussack, G.; Tanha, J.; Kitova, E.N.; Klassen, J.S.; Ng, K.K.S. (Journal of Biological Chemistry, 2014)
Background: TcdA and TcdB are the main virulence factors for Clostridium difficile infections. Results: X-ray crystallography, mass spectrometry, and size exclusion chromatography reveal the molecular basis of antibody recognition. Conclusion: Neutralizing antibodies do not directly block binding to known receptors, suggesting new mechanisms of neutralization. Significance: The molecular details of antibody recognition will assist with the development of novel therapeutics and diagnostics. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Highly efficient thieno[3,4-c]pyrrole-4,6-dione-based solar cells processed from non-chlorinated solvent - Aïch, B.R.; Beaupré, S.; Leclerc, M.; Tao, Y. (Organic Electronics: physics, materials, applications, 2014)
To obtain high performance bulk heterojunction organic solar cells, the selection of solvents to prepare the donor/acceptor blend is as important as the choice of the donor/acceptor materials themselves. State-of-the-art lab-scale polymer solar cells have evolved around chlorinated solvents such as chloroform, chlorobenzene and o-dichlorobenzene. However, for large scale applications, benign processing solvents may become inevitable. In this work, we used a mixture of Xylenes (a chlorine-free solvent), methyl naphthalene (MeN) and 1,8-diiodoctane (DIO) to modulate the nano-scale morphology of poly(4,4-bis(2-ethylhexyl)-dithieno[3,2-b:2′,3′-d]silole-alt-1, 3-(5-octylthieno[3,4-c]pyrrole-4,6-dione) (PDTSTPD)/PCBM blend, one of the most efficient active layer in polymeric solar cell. Power conversion efficiencies up to 5.5% (with PC61BM) and 6.2% (with PC71BM) were obtained for photovoltaic devices with an active area of 1.0 cm2. © 2013 Elsevier B.V. All rights reserved.
Keywords: Bulk heterojunction; Bulk heterojunction organic solar cells; Large-scale applications; Non-chlorinated solvents; Polymer Solar Cells; Polymeric solar cells; Power conversion efficiencies; Thieno[3,4-c]pyrrole-4,6-dione; Additives; Aromatic compounds; Carbon inorganic compounds; Heterojunctions; Naphthalene; Polymers; Solar cells; Solvents; Nanostructured materials

Evaluation of homogeneity and genetic stability of REOLYSIN® (pelareorep) by complete genome sequencing of reovirus after large scale production - Chakrabarty, R.; Tran, H.; Fortin, Y.; Yu, Z.; Shen, S.-H.; Kolman, J.; Onions, D.; Voyer, R.; Hagerman, A.; Serl, S.; Kamen, A.; Thompson, B.; et al. (Applied Microbiology and Biotechnology, 2014)
REOLYSIN® (pelareorep) is a proprietary isolate of the reovirus T3D (Type 3 Dearing) strain which is currently being tested in clinical trials as an anticancer therapeutic agent. Reovirus genomes are composed of ten segments of double-stranded ribonucleic acid (RNA) characterized by genome size: large (L1, L2, and L3), medium (M1, M2, and M3), and small (S1, S2, S3, and S4). The objective of this work was to evaluate the homogeneity and genetic stability of REOLYSIN®. Sanger sequencing (SS) performed on test articles derived from the Master Virus Bank (MVB) and Working Virus Bank (WVB) identified many modifications when compared to GenBank reference sequences. Massively parallel sequencing (MPS) using Roche-454 sequencing was performed on REOLYSIN® (100 L scale) and resulted in 69,821,115 bases and an average of 335 bases per read. Twenty-nine high confidence differences relative to the GenBank reference sequence were identified in REOLYSIN® by MPS. Of those, 27 were previously identified by SS in the virus bank-derived test articles. Of the remaining two nucleotide differences, one was predicted to be silent at the amino acid level (L3 genome-T3163C, codon 1054, 86 % of the population was "T" and 13 % of the population were reported as "C"). The other modification was in the noncoding region (M1 genome-A2284A to A2284G), and A2284G was present in 97 % of the population. The results obtained from MPS were comparable to those from SS; both demonstrate a high level of homogeneity at the amino acid level and genetic stability of REOLYSIN®. Finally, phylogenetic analysis of the REOLYSIN® L1 genome segment showed close evolutionary relationship with its human homologs, serotypes Lang and Dearing. © 2014 Springer-Verlag Berlin Heidelberg.

Towards better predictions of theatre chair absorption using the perimeter-to-area method - Choi, Y.-J.; Bradley, J.S.; Jeong, D.-U. (Applied Acoustics, 2014)
The present study investigated factors influencing the precision of the perimeter-to-area (P/A) method for predicting the absorption coefficients of theatre chairs in an auditorium, and proposes guidelines for obtaining more precise predictions. Regression lines were fitted to measurements of the absorption coefficients of blocks of theatre chairs with a range of P/A ratios obtained in full scale and scale model reverberation chambers. The choice of numbers of samples, and sample P/A ratios, influenced the precision of regression lines. Samples should be chosen to include a wide range of P/A values, but should not include cases with only 1 row or only 1 chair in each row of sample blocks of chairs. Including a row space in front of the first row of each block of chairs, when calculating sample perimeters and areas, is more likely to lead to more precise predictions than excluding it. The precision of regression lines was also seen to vary with the type of chair such that low absorption chairs and high absorption chairs tended to have less precise regression results. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Absorption co-efficient; Measurements of; Perimeter to areas; Regression lines; Reverberation chambers; Scale modeling; Theatre chairs; Forecasting; Regression analysis; Reverberation; Theaters

Separation and characterization of alkaloids in goldenseal (Hydrastis canadensis) by ultra-performance liquid chromatography coupled with electrospray ionization quadruple time of flight mass spectrometry (UPLC/Q-TOF-MS) - Le, P.M.; McCooeye, M.; Windust, A. (Analytical and Bioanalytical Chemistry, 2014)
Here, we describe a new application of ultra-performance liquid chromatography coupled with an electrospray ionization quadrupole time-of-flight mass spectrometry operating in MSE mode (UPLC-QTOF-MSE) for the sensitive, fast, and effective characterization of alkaloids in goldenseal (Hydrastis canadensis). This approach allowed identification of alkaloids using a cyclic low and high collision energy spectral acquisition mode providing simultaneous accurate precursor and fragment ion mass information. A total of 45 compounds were separated and 40 of them characterized including one new compound and 7 identified for the first time in goldenseal. The spectral data obtained using this method is comparable to those obtained by conventional LC-MSn. However, the UPLC-QTOF-MSE method offers high chromatographic resolution with structural characterization facilitated by accurate mass measurement in both MS and MS/MS modes in a single analytical run; this makes it suitable for the rapid analysis and screening of alkaloids in plant extracts. [Figure not available: see fulltext.] © 2014 Her Majesty the Queen in Right of Canada.

Residual stress, thermomechanics and infrared imaging, hybrid techniques and inverse problems. Volume 8 - Rossi, Marco; Sasso, Marco; Connesson, Nathanael; Singh, Raman; DeWald, Adrian; Backman, David; Gloeckner, Paul (Conference Proceedings of the Society for Experimental Mechanics Series : Residual stress, thermomechanics and infrared imaging, hybrid techniques and inverse problems, 2014)

Effect of hydrogen and helium addition to fuel on soot formation in an axisymmetric coflow laminar methane/air diffusion flame - Liu, F.; Ai, Y.; Kong, W. (International Journal of Hydrogen Energy, 2014)
A detailed numerical study was conducted to investigate the effects of hydrogen and helium addition to fuel on soot formation in atmospheric axisymmetric coflow laminar methane/air diffusion flame. Detailed gas-phase chemistry and thermal and transport properties were employed in the numerical calculations. Soot was modeled using a PAH based inception model and the HACA mechanism for surface growth and oxidation. Numerical results were compared with available experimental data. Both experimental and numerical results show that helium addition is more effective than hydrogen addition in reducing soot loading in the methane/air diffusion flame. These results are different from the previous investigations in ethylene/air diffusion flames. Hydrogen chemically enhances soot formation when added to methane. The different chemical effects of hydrogen addition to ethylene and methane on soot formation are explained in terms of the different effects of hydrogen addition on propargyl, benzene, and pyrene formation low in the flames. Crown Copyright © 2014.

Using hashtags to capture fine emotion categories from tweets - Mohammad, S.M.; Kiritchenko, S. (Computational Intelligence, 2014)
Detecting emotions in microblogs and social media posts has applications for industry, health, and security. Statistical, supervised automatic methods for emotion detection rely on text that is labeled for emotions, but such data are rare and available for only a handful of basic emotions. In this article, we show that emotion-word hashtags are good manual labels of emotions in tweets. We also propose a method to generate a large lexicon of word-emotion associations from this emotion-labeled tweet corpus. This is the first lexicon with real-valued word-emotion association scores. We begin with experiments for six basic emotions and show that the hashtag annotations are consistent and match with the annotations of trained judges. We also show how the extracted tweet corpus and word-emotion associations can be used to improve emotion classification accuracy in a different nontweet domain.Eminent psychologist Robert Plutchik had proposed that emotions have a relationship with personality traits. However, empirical experiments to establish this relationship have been stymied by the lack of comprehensive emotion resources. Because personality may be associated with any of the hundreds of emotions and because our hashtag approach scales easily to a large number of emotions, we extend our corpus by collecting tweets with hashtags pertaining to 585 fine emotions. Then, for the first time, we present experiments to show that fine emotion categories such as those of excitement, guilt, yearning, and admiration are useful in automatically detecting personality from text. Stream-of-consciousness essays and collections of Facebook posts marked with personality traits of the author are used as test sets. © 2014 National Research Council Canada.

Illuminating silicon surface hydrosilylation: An unexpected plurality of mechanisms - Buriak, J.M. (Chemistry of Materials, 2014)
Silicon is the cornerstone material of the semiconductor industry. As feature sizes on chips continue to decrease in size, the ratio of surface to bulk increases, and as a result, the role of surface defects, surface states and other subtle features play larger roles in the functioning of the device. Although silicon oxides have served the industry well as the passivation chemistry of choice, there is interest in expanding the repertoire of accessible and efficient chemical functional strategies available for use, and to fully understand the nature of these interfaces. For new applications such as molecular electronics on silicon and biochips, for example, there is a need to avoid the layer of intervening insulating oxide: A well-defined linkage of organic molecules through a silicon-carbon bond has great promise and appeal. Hydrosilylation, the insertion of an alkene or alkyne into a surface Si-H bond, is an ideal approach to producing these covalent Si-C bonds, and can be carried out in a number of ways. Light-promoted hydrosilylation is promising because it is clean and direct and can be patterned via masking; it requires no additional reagents such as catalysts or input of thermal energy and thus may have reduced surface contamination and numbers of defects. In this perspective, we start by making connections between the molecular silane literature, and the first reports of UV-mediated hydrosilylation of an alkene on a silicon surface, a reaction that was assumed to operate via a radical mechanism. We then describe the unexpected development of four new mechanisms that have no obvious parallels with the molecular silane literature, and take place as a result of the solid state electronics of the underlying silicon itself. From exciton involvement, to the influence of plasmonics, to the role of photoemission, the area of silicon surface hydrosilylation has become incredibly rich, and undoubtedly still contains new reactivity to be discovered. © 2013 American Chemical Society.

Comparison of manual and semi-automated segmentation methods to evaluate hippocampus volume in APP and PS1 transgenic mice obtained via in vivo magnetic resonance imaging - Hayes, K.; Buist, R.; Vincent, T.J.; Thiessen, J.D.; Zhang, Y.; Zhang, H.; Wang, J.; Summers, A.R.; Kong, J.; Li, X.-M.; Martin, M. (Journal of Neuroscience Methods, 2014)
Background: Magnetic resonance imaging (MRI) of transgenic mouse models of Alzheimer's disease is valuable to understand better the structural changes that occur in the brain and could provide a means to test drug treatments. A hallmark pathological feature of Alzheimer's disease is atrophy of the hippocampus, which is an early biomarker of the disease. MRI can be used to detect and monitor this biomarker. Method: Repeated measurements using in vivo 3D T2-weighted imaging of mice were used to assess the methods. Each mouse was imaged twice in one week and twice the following week and no changes in volume were expected. The hippocampus was segmented both manually and semi-automatically. Registration was done to gain information on shape changes. The volumes from each mouse were compared intra-mouse, between mice and to hippocampus volume values in the literature. Results: A reliable method was developed which was able to detect difference in volumes of hippocampus between mice when performed by a single individual. The semi-automated segmentation was unable to detect the same level of differences. The semi-automated segmentation method gave larger hippocampus volumes, with 78-87% reliability between the manual and semi-automated segmentation. Although more accurate, the manual segmentation is laborious and suffers from inter- and intra-variability. Conclusion: These results suggest that manual segmentation is still considered the most reliable segmentation method for small structures. However, if performing longitudinal studies, where there is at least one year between imaging sessions, the segmentation should be done all at once at the end of all the imaging sessions. If segmentation is done after each imaging session, with at least a year passing between segmentations, very small variations in volumes can be missed. This method provides a means to quantify the volume of the hippocampus in a live mouse using manual segmentation, which is the first step toward studying hippocampus atrophy in a mouse model of Alzheimer's disease. © 2013 Elsevier B.V.
Keywords: animal experiment; article; brain size; controlled study; hippocampus; intermethod comparison; male; manual segmentation; mouse; neuroimaging; neurological and sensorial procedures; nonhuman; nuclear magnetic resonance imaging; priority journal; semi automated segmentation; signal noise ratio; three dimensional imaging; transgenic mouse

Modeling gravitational collapse of rectangular granular piles in air and water - Savage, S.B.; Babaei, M.H.; Dabros, T. (Mechanics Research Communications, 2014)
The present paper is concerned with the two-dimensional collapse of piles of granular materials, a problem analogous to the classical dam break problem in hydraulics. This study is intended to aid in the development of constitutive equations and modeling procedures that can be applied to predict various flows involving high concentration liquid-particle mixtures. We consider the granular collapse as a test problem and attempt to validate our modeling by comparing our predictions with previously published granular collapse experiments. The time-dependent evolution of the collapsing granular piles is calculated by making use of COMSOL, a commercial finite element code that is designed to handle a wide variety of Multiphysics problems. We begin by considering the collapse of a rectangular block of dry granular material and calculate the temporal evolution of the free surface by making use of the Level Set method. Good agreement is found between these predictions and the laboratory experiments of Balmforth and Kerswell (2005). The collapse of granular material submerged in a water is then investigated using a Mixture Model approach. The experiments of Rondon et al. (2011) revealed drastically different collapse periods depending upon whether the initial pile was in a loose or a dense, compacted state. The simple Mixture Model approach gave reasonably good predictions of the Rondon et al. (2011) experiments for the case of initially loose piles that collapsed in about a second, but it was unsuccessful in simulating the collapse of the initially dense piles that were observed by Rondon et al. (2011) to take around 30-40 s. Some simple empirical modifications to the material constitutive behavior were able to roughly predict such long collapse times, but a more comprehensive and detailed investigation of the phenomenon is warranted. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Commercial finite element codes; Constitutive behaviors; Fluid solids; Gravitational collapse; Laboratory experiments; Level Set method; Mixture model; Time-dependent evolutions; Channel flow; Drop breakup; Experiments; Forecasting; Granular materials; Gravitational effects; Level measurement; Mixtures; Stars; Piles

Effects of different electrolytes containing Na2WO4 on the electrochemical performance of nickel hydroxide electrodes for nickel-metal hydride batteries - Shangguan, E.; Li, J.; Guo, D.; Chang, Z.; Yuan, X.-Z.; Wang, H. (International Journal of Hydrogen Energy, 2014)
To improve the high-temperature performance of the nickel hydroxide electrodes in nickel-metal hydride batteries, sodium tungstate (Na2WO4) used as an electrolyte additive has been added into two types of binary electrolytes (KOH-LiOH and NaOH-LiOH) in this study. The effects of electrolyte composition on the electrochemical performance of nickel electrodes have been systematically investigated via a combination of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD) and charge/discharge tests. It is found that by adding (1.0 wt.%) Na2WO4, the performance of nickel electrodes is significantly improved in both NaOH and KOH electrolytes at 70 °C. The improved performance can be attributed to the deposition of WO3·2H2O solid film on the surface of nickel electrode, which is beneficial to the increase in oxygen evolution overpotential, the slow-down of oxygen evolution rate and the decrease in charge-transfer resistance. © 2013 Hydrogen Energy Publications, LLC.

Exploiting the metabolism of PYC expressing HEK293 cells in fed-batch cultures - Vallée, C.; Durocher, Y.; Henry, O. (Journal of Biotechnology, 2014)
The expression of recombinant yeast pyruvate carboxylase (PYC) in animal cell lines was shown in previous studies to reduce significantly the formation of waste metabolites, although it has translated into mixed results in terms of improved cellular growth and productivity. In this work, we demonstrate that the unique phenotype of PYC expressing cells can be exploited through the application of a dynamic fed-batch strategy and lead to significant process enhancements. Metabolically engineered HEK293 cells stably producing human recombinant IFNα2b and expressing the PYC enzyme were cultured in batch and fed-batch modes. Compared to parental cells, the maximum cell density in batch was increased 1.5-fold and the culture duration was extended by 2.5 days, but the product yield was only marginally increased. Further improvements were achieved by developing and implementing a dynamic fed-batch strategy using a concentrated feed solution. The feeding was based on an automatic control-loop to maintain a constant glucose concentration. This strategy led to a further 2-fold increase in maximum cell density (up to 10.7×106cells/ml) and a final product titer of 160mg/l, representing nearly a 3-fold yield increase compared to the batch process with the parental cell clone. © 2013.
Keywords: Animal cell lines; Fed batches; Fed-batch cultures; Glucose concentration; HEK293 cells; Process enhancements; Pyruvate carboxylase; Recombinant yeast; Automation; Batch data processing; Cells; Control; Cytology; Recombinant proteins; Batch cell culture; glucose; pyruvate carboxylase; recombinant alpha2b interferon; animal cell; article; batch process; cell clone; cell density; cell strain HEK293; controlled study; enzyme metabolism; fed batch culture; nonhuman; phenotype; priority journal; yeast

Editorial - Love, P.E.D.; Ding, L.; Luo, H.; Shen, W. (Expert Systems with Applications, 2014)

Coverage path planning for eddy current inspection on complex aeronautical parts - Olivieri, P.; Birglen, L.; Maldague, X.; Mantegh, I. (Robotics and Computer-Integrated Manufacturing, 2014)
Non-destructive testing (NDT) plays a critical role in controlling the structural integrity (therefore the quality) of aeronautical parts, during fabrication as well as during maintenance. Eddy current (EC) testing is one of the most used NDT techniques in the aerospace industry. However, EC testing is still mainly performed by human operators and reliability as well as repeatability is not always guaranteed. To solve these issues, automating this NDT technique with a robotic system is investigated. In this paper, an EC probe equipped with a passive compliant system is assumed to be attached to the end-effector of a 6-DOF manipulator arm to carry on the inspection. Then, assuming that a 3D model of the inspected part is known a priori, a coverage path planning method using a zigzag (or rastering) pattern adapted to EC testing on aeronautical structures with a complex geometry is proposed. To reach this objective, the approach adopted in this work is to adapt existing coverage path planning techniques based on a "divide-and-conquer" strategy used for spraying applications to EC inspection. More precisely, three successive segmentations are applied to the surface to be inspected so that consistent rastering paths can be generated. Simulation results are shown for a complex part of an aeronautical structure to demonstrate the efficiency of the proposed method. © 2013 Elsevier Ltd.
Keywords: Aeronautical structures; Complex geometries; Coverage path planning; Divide and conquer; Eddy-current inspection; Manipulator arms; Non destructive testing; Triangular meshes; Aerospace industry; Automation; Image segmentation; Inspection; Motion planning; Eddy current testing

Reconstruction of historic sea ice conditions in a sub-Arctic lagoon - Petrich, C.; Tivy, A.C.; Ward, D.H. (Cold Regions Science and Technology, 2014)
Historical sea ice conditions were reconstructed for Izembek Lagoon, Bering Sea, Alaska. This lagoon is a crucial staging area during migration for numerous species of avian migrants and a major eelgrass (Zostera marina) area important to a variety of marine and terrestrial organisms, especially Pacific Flyway black brant geese (Branta bernicla nigricans). Ice cover is a common feature of the lagoon in winter, but appears to be declining, which has implications for eelgrass distribution and abundance, and its use by wildlife. We evaluated ice conditions from a model based on degree days, calibrated to satellite observations, to estimate distribution and long-term trends in ice conditions in Izembek Lagoon. Model results compared favorably with ground observations and 26. years of satellite data, allowing ice conditions to be reconstructed back to 1943. Specifically, periods of significant (limited access to eelgrass areas) and severe (almost complete ice coverage of the lagoon) ice conditions could be identified. The number of days of severe ice within a single season ranged from 0 (e.g., 2001) to ≥ 67 (e.g., 2000). We detected a slight long-term negative trend in ice conditions, superimposed on high inter-annual variability in seasonal aggregate ice conditions. Based on reconstructed ice conditions, the seasonally cumulative number of significant or severe ice days correlated linearly with mean air temperature from January until March. Further, air temperature at Izembek Lagoon was correlated with wind direction, suggesting that ice conditions in Izembek Lagoon were associated with synoptic-scale weather patterns. Methods employed in this analysis may be transferable to other coastal locations in the Arctic. © 2013 Elsevier B.V.
Keywords: Cumulative number; Degree days; Ground observations; Interannual variability; Mean air temperatures; Satellite observations; Sea ice conditions; Terrestrial organisms; Atmospheric temperature; Models; Plants (botany); Remote sensing; Sea ice; Lakes; air temperature; ice cover; lagoon; remote sensing; satellite data; sea ice; wind direction; Alaska; Izembek Lagoon; United States; Anser; Aves; Branta bernicla nigricans; Zostera marina

A Framework for Risk-Informed Performance-Based Fire Protection Design for the Built Environment - Alvarez, A.; Meacham, B.J.; Dembsey, N.A.; Thomas, J.R. (Fire Technology, 2014)
Performance-based fire protection design (PBFPD) approaches have now been in use for more than 20 years. One might be tempted to conclude that the current 'state of the art' is working well. However, application of PBFPD remains limited, several shortcomings exist, and an increasing number of countries are moving toward 'prescribed performance' to address the gaps. There are many factors contributing to these problems with PBFPD. Research has been carried out in two principal problem areas: the relationship between occupants and fire safety measures in the context of holistic building performance expectations during everyday use of the building, and also the lack of specifics within current PBFPD approaches. To address these concerns, a new framework for risk-informed PBFPD has been developed, centered on the study of systems formed by specific building types and their associated occupants. This framework replaces generic guidance with a more in-depth and targeted "building-occupant" system approach. This article focuses on how a successful implementation of the new risk-informed PBFPD approach will require acceptance of the need for a paradigm shift from one in which fire is the center of the problem to one in which building performance metrics are evaluated in case of fire events. This article also details the different steps of the new PBFPD process and how this process differs from the current ones, notably in separating technical steps from political steps related to decision making and policy. Finally, this article presents how the new approach is practically applied to a project, focusing on a proof of concept of the new PBFPD process. © 2013 Springer Science+Business Media New York.

Kinetics of oxygen reduction reaction on three different Pt surfaces of Pt/C catalyst analyzed by rotating ring-disk electrode in acidic solution - Zhang, L.; Li, H.; Zhang, J. (Journal of Power Sources, 2014)
The oxygen reduction reaction (ORR) on a Pt/C-based thin catalyst layer is studied using the rotating ring-disk electrode (RRDE) technique in an O 2-saturated acid solution. A modified model for obtaining the ORR constants in different electrode potential ranges is validated using the experimental disk and ring currents. The results calculated from the model and the Koutecky-Levich plots reveal that the ORR constants on three different Pt surfaces (Pt-H, Pt, and PtOX/Pt) are significantly different, among which, pure Pt surface is found to have the best activity towards ORR. This model can also give a detailed formularization of the apparent ORR electron transfer number (n) and the percentage of H2O2 (%H 2O2) produced during the ORR process. © 2014 Published by Elsevier B.V.

Biomolecular sample considerations essential for optimal performance from cryogenic probes - Biswas, Zakia; Merkley, Nadine; Syvitski, Raymond T. (Metabolomics, 2014)
For compounds dissolved in non-polar solvents, nuclear magnetic resonance spectroscopic investigations have benefited greatly from the advent of cryogenically cooled probes. Unfortunately the allure of significant increases in sensitivity may not be realized for compounds such as metabolites that are dissolved in solvents with high ionic-strengths such as solutions typically utilized for metabolomic or biomolecular investigations. In some cases there is little benefit from a cryogenically cooled probe over a conventional room temperature probe. Various sample preparation methods have been developed to minimize the detrimental effects of salt; for large numbers of metabolomic samples these preparation methods tend to be onerous and impractical. An alternative to manipulating the sample, is to utilize a probe that is designed to have a higher tolerance for solutions with high ionic-strengths. In order to acquire high-quality optimal data and choose the appropriate probe configuration (especially important for comparative quantitative investigations) the effects of salts and buffers on cryogenic probe performance must be understood. Herein we detail sample considerations for two cryogenic probes, a standard 5 mm and a narrow diameter 1.7 mm, in an effort to identify via integrals, intensities and noise levels the optimal choice for biomolecular investigations.
Keywords: 1.7 and 5 mm cryogenic probes; Biomolecular samples; Metabolomic data collection; Quantitation; Salt tolerance

Effects of water vapor addition to the air stream on soot formation and flame properties in a laminar coflow ethylene/air diffusion flame - Liu, F.; Consalvi, J.-L.; Fuentes, A. (Combustion and Flame, 2014)
The effects of adding water vapor to the air stream on flame properties and soot volume fraction were investigated numerically in a laminar coflow ethylene/air diffusion flame at atmospheric pressure by solving the fully elliptic conservation equations and using a detailed C2 reaction mechanism including PAH up to pyrene and detailed thermal and transport properties. Thermal radiation was calculated using the discrete-ordinates method and a statistical narrow-band correlated-k based wide band model for the absorption coefficients of CO2 and H2O. Soot formation was modeled using a PAH based inception model and the HACA mechanism for surface growth and oxidation. Addition of water vapor significantly reduces radiation heat loss from the flame primarily through reduced soot loading and flame temperature. The added water vapor affects soot formation and flame properties through not only dilution and thermal effects, but also through chemical effect. The chemical effect is as significant as the dilution and thermal effects. The primary pathway for the chemical effect of water vapor is the reverse reaction of OH + H2 ↔ H + H2O. Our numerical results confirm that the reduced H radical concentration leads to lower PAH concentrations and consequently lower soot inception rates. In contrast, the radiation effect due to the added water vapor was found to have a minor influence on both flame structure and soot formation in the laminar diffusion flame investigated. Crown Copyright © 2014.

A catalog of bulge, disk, and total stellar mass estimates for the Sloan Digital Sky Survey - Mendel, J.T.; Simard, L.; Palmer, M.; Ellison, S.L.; Patton, D.R. (Astrophysical Journal, Supplement Series, 2014)
We present a catalog of bulge, disk, and total stellar mass estimates for 660,000 galaxies in the Legacy area of the Sloan Digital Sky Survey Data (SDSS) Release 7. These masses are based on a homogeneous catalog of g- and r-band photometry described by Simard et al., which we extend here with bulge+disk and Sérsic profile photometric decompositions in the SDSS u, i, and z bands. We discuss the methodology used to derive stellar masses from these data via fitting to broadband spectral energy distributions (SEDs), and show that the typical statistical uncertainty on total, bulge, and disk stellar mass is 0.15 dex. Despite relatively small formal uncertainties, we argue that SED modeling assumptions, including the choice of synthesis model, extinction law, initial mass function, and details of stellar evolution likely contribute an additional 60% systematic uncertainty in any mass estimate based on broadband SED fitting. We discuss several approaches for identifying genuine bulge+disk systems based on both their statistical likelihood and an analysis of their one-dimensional surface-brightness profiles, and include these metrics in the catalogs. Estimates of the total, bulge and disk stellar masses for both normal and dust-free models and their uncertainties are made publicly available here. © 2014. The American Astronomical Society. All rights reserved..

Effects of γ-CoOOH coating on the high-temperature and high-rate performances of spherical nickel hydroxide electrodes - Guo, D.; Shangguan, E.; Li, J.; Zhao, T.; Chang, Z.; Li, Q.; Yuan, X.-Z.; Wang, H. (International Journal of Hydrogen Energy, 2014)
To improve the high-temperature and high-rate performances of nickel hydroxide electrodes in nickel-metal hydride (Ni/MH) batteries, γ-CoOOH is coated onto spherical Ni(OH)2 through surface modification. X-ray diffraction, scanning electron microscopy with energy dispersive X-ray, and X-ray photoelectron spectroscopy are used to characterize the synthesized products. The effects of γ-CoOOH on the electrochemical performance of nickel electrodes are investigated using cyclic voltammetry, electrochemical impedance spectroscopy, and a charge/discharge test. It is found that the spherical γ-CoOOH-coated Ni(OH)2 electrode without adding any conductive additives exhibits superior electrode properties including excellent high-temperature and high-rate discharge abilities, and superior cycling reversibility. These performance improvements are ascribed to the enhancement of oxygen evolution over-potential, slower oxygen evolution rate and lower charge transfer resistance resulting from the high conductivity coating of γ-CoOOH. © 2013 Hydrogen Energy Publications, LLC.

Object shape-based optical sensing methodology and system for condition monitoring of contaminated engine lubricants - Bordatchev, E.; Aghayan, H.; Yang, J. (Optics and Lasers in Engineering, 2014)
Presence of contaminants, such as gasoline, moisture, and coolant in the engine lubricant indicates mechanical failure within the engine and significantly reduces lubricant quality. This paper describes a novel sensing system, its methodology and experimental verifications for analysis of the presence of contaminants in the engine lubricants. The sensing methodology is based on the statistical shape analysis methodology utilizing optical analysis of the distortion effect when an object image is obtained through a thin random optical medium. The novelty of the proposed sensing system lies within the employed methodology which an object with a known periodic shape is introduced behind a thin film of the contaminated lubricant. In this case, an acquired image represents a combined lubricant-object optical appearance, where an a priori known periodical structure of the object is distorted by a contaminated lubricant. The object, e.g. a stainless steel woven wire cloth with a mesh size of 65×65 μm2 and a circular wire diameter of 33 μm was placed behind a microfluidic channel, containing engine lubricant and optical images of flowing lubricant with stationary object were acquired and analyzed. Several parameters of acquired optical images, such as, color of lubricant and object, object shape width at object and lubricant levels, object relative color, and object width non-uniformity coefficient, were proposed. Measured on-line parameters were used for optical analysis of fresh and contaminated lubricants. Estimation of contaminant presence and lubricant condition was performed by comparison of parameters for fresh and contaminated lubricants. Developed methodology was verified experimentally showing ability to distinguish lubricants with 1%, 4%, 7%, and 10% coolant, gasoline and water contamination individually and in a combination form of coolant (0%-5%) and gasoline (0%-5%). Crown Copyright © 2013 Published by Elsevier Ltd. All rights reserved.
Keywords: Automotive engine; Condition; Experimental verification; Mechanical failures; Microfluidic channel; Optical analysis; Periodical structure; Statistical shape analysis; Condition monitoring; Contamination; Coolants; Engines; Gasoline; Geometrical optics; Impurities; Measurements; Monitoring; Object recognition; Sensors; Water pollution; Wire; Lubricants

Impact of wastewater treatment processes on antimicrobial resistance genes and their co-occurrence with virulence genes in Escherichia coli - Biswal, B.K.; Mazza, A.; Masson, L.; Gehr, R.; Frigon, D. (Water Research, 2014)
An increase in the frequency of antimicrobial resistance genes (ARGs) in bacteria including Escherichia coli could be a threat to public health. This study investigated the impact of activated sludge and physicochemical wastewater treatment processes on the prevalence of ARGs in E. coli isolates. In total, 719 E. coli were isolated from the influent and effluent (prior to disinfection) of two activated sludge and two physicochemical municipal treatment plants, and genotyped using DNA microarrays. Changes in the abundance of ARGs in the E. coli population were different for the two treatment processes. Activated sludge treatment did not change the prevalence of ARG-possessing E. coli but increased the abundance of ARGs in the E. coli genome while physicochemical treatment reduced both the prevalence of ARG-carrying E. coli as well as the frequency of ARGs in the E. coli genome. Most E. coli isolates from the four treatment plants possessed ARGs of multiple antimicrobial classes, mainly aminoglycoside, β-lactams, quinolone and tetracyclines. In addition these isolates harboured DNA insertion sequence elements including integrase and transposase. A significant positive association was found between the occurrence of ARGs and virulence genotypes. © 2013 Elsevier Ltd.
Keywords: Activated sludge; Antimicrobial resistances; DNA micro-array; Insertion sequences; Physicochemical; Activated sludge process; Bioassay; Biochips; Effluent treatment; Effluents; Genes; Microorganisms; Wastewater treatment; Escherichia coli; aminoglycoside; antibiotic agent; beta lactam antibiotic; DNA; integrase; quinolone; tetracycline derivative; transposase; activated sludge; disinfection; fecal coliform; gene; genome; genotype; public health; sewage treatment; virulence; activated sludge; antibiotic resistance; article; bacterial gene; bacterial genome; bacterial virulence; bacterium isolation; controlled study; DNA microarray; DNA sequence; effluent; Escherichia coli; gene insertion; genotype; genotyping technique; influent; nonhuman; physical chemistry; priority journal; waste water management; waste water treatment plant; water pollutant

A first look at the disk population in the Auriga-California Molecular Cloud - Broekhoven-Fiene, Hannah; Matthews, Brenda C.; Harvey, Paul M. (Exploring the Formation and Evolution of Planetary Systems, 2014)
The Auriga-California Molecular Cloud (AMC) is one of two nearby (within 500 pc) giant molecular clouds, the other being the Orion A Molecular Cloud (OMC). We aim to study the properties of circumstellar disks in the AMC to compare the planet formation potential and processes within the AMC to those for other clouds. A first look with measurements from Spitzer observations suggests that AMC disk properties, such as the distribution of disk luminosities and the evolution of the mid-IR excesses, are not vastly different from those in other regions. Follow-up observations in the submm, mm and cm can be used to measure disk masses and the degree of grain growth from spectral slopes to more completely characterize the disk population.
Keywords: Star formation; Planetary systems; Protoplanetary disks; ISM clouds

On the kinematic separation of field and cluster stars across the bulge globular NGC 6528 - Lagioia, E.P.; Milone, A.P.; Stetson, P.B.; Bono, G.; Prada Moroni, P.G.; Dall'Ora, M.; Aparicio, A.; Buonanno, R.; Calamida, A.; Ferraro, I.; Gilmozzi, R.; Iannicola, G.; et al. (The Astrophysical Journal, 2014)
We present deep and precise multi-band photometry of the Galactic bulge globular cluster NGC 6528. The current data set includes optical and near-infrared images collected with ACS/WFC, WFC3/UVIS, and WFC3/IR on board the Hubble Space Telescope. The images cover a time interval of almost 10 yr, and we have been able to carry out a proper-motion separation between cluster and field stars. We performed a detailed comparison in the m F814W, m F606W-m F814W color-magnitude diagram with two empirical calibrators observed in the same bands. We found that NGC 6528 is coeval with and more metal-rich than 47 Tuc. Moreover, it appears older and more metal-poor than the super-metal-rich open cluster NGC 6791. The current evidence is supported by several diagnostics (red horizontal branch, red giant branch bump, shape of the sub-giant branch, slope of the main sequence) that are minimally affected by uncertainties in reddening and distance. We fit the optical observations with theoretical isochrones based on a scaled-solar chemical mixture and found an age of 11 ± 1 Gyr and an iron abundance slightly above solar ([Fe/H] = +0.20). The iron abundance and the old cluster age further support the recent spectroscopic findings suggesting a rapid chemical enrichment of the Galactic bulge. © 2014. The American Astronomical Society. All rights reserved.

Kinetic inhibition of natural gas hydrates in saline solutions and heptane - Sharifi, H.; Ripmeester, J.; Walker, V.K.; Englezos, P. (Fuel, 2014)
The performance of polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap) as kinetic gas hydrate inhibitors in saline solutions and with heptane was evaluated using high pressure microdifferential scanning calorimetry, as well as with a new apparatus, consisting of two high pressure stainless steel crystallizers. Although PVP and PVCap were found to prolong natural gas hydrate induction time in saline solutions, nucleation was followed by catastrophic hydrate crystal growth. PVP was found to be more effective in this case, since this hydrate growth was modestly slower. The addition of n-heptane to the natural gas in the system created a 4th phase. This resulted in increased induction time and a slowing of hydrate growth relative to the gas mixture. Unexpectedly, in the presence of n-heptane, addition of kinetic hydrate inhibitors (KHIs) decreased induction time, but catastrophic growth did not occur. Here PVCap was more effective than PVP in both prolonging the induction time and decreasing the rate of hydrate crystal growth. Once formed, however, hydrate decomposition took longer and proceeded in two steps in the presence of n-heptane. This observation has profound applications on the use these KHIs under ocean field conditions. In the case of hydrate blockages, our observations that hydrate dissociation started later with the KHIs and complete dissociation took longer could have far reaching economic implications for industry. © 2013 Elsevier Ltd. All rights reserved.
Keywords: Economic implications; Flow assurance; Hydrate decomposition; Kinetic hydrate inhibitors; Liquid hydrocarbons; Polyvinyl pyrrolidone; Saline solutions; Scanning calorimetry; Crystal growth; Heptane; Hydration; Kinetics; Natural gas; Gas hydrates

Serum resistance, gallium nitrate tolerance and extrapulmonary dissemination are linked to heme consumption in a bacteremic strain of Acinetobacter baumannii - de Léséleuc, L.; Harris, G.; KuoLee, R.; Xu, H.H.; Chen, W. (International Journal of Medical Microbiology, 2014)
Bacteremia caused by Acinetobacter baumannii is a highly lethal complication of hospital-acquired pneumonia. In the present study, we investigated the serum resistance, gallium nitrate tolerance and heme consumption of A. baumannii strain LAC-4 which was recently reported to display high virulence in a mouse pneumonia model with extrapulmonary dissemination leading to fatal bacteremia. This strain showed enhanced growth in mouse and fetal bovine serum that was independent of complement and was not observed with regular growth media. The LAC-4 strain was found to possess a high tolerance to gallium nitrate (GaN), whereas serum synergized with GaN in inhibiting A. baumannii strain ATCC 17978. We found that LAC-4 contains a heme oxygenase gene and expresses a highly efficient heme consumption system. This system can be fully blocked in vitro and in vivo by gallium protoporphyrin IX (GaPPIX). Inhibition of heme consumption by GaPPIX completely abrogated the growth advantage of LAC-4 in serum as well as its tolerance to GaN. More importantly, GaPPIX treatment of mice intranasally infected with LAC-4 prevented extrapulmonary dissemination and death. Thus, we propose that heme provides an additional source of iron for LAC-4 to bypass iron restriction caused by serum transferrin, lactoferrin or free gallium salts. Heme consumption systems in A. baumannii may constitute major virulence factors for lethal bacteremic isolates. © 2014.

Production of adeno-associated virus (AAV) serotypes by transient transfection of HEK293 cell suspension cultures for gene delivery - Chahal, P.S.; Schulze, E.; Tran, R.; Montes, J.; Kamen, A.A. (Journal of Virological Methods, 2014)
Adeno-associated virus (AAV) is being used successfully in gene therapy. Different serotypes of AAV target specific organs and tissues with high efficiency. There exists an increasing demand to manufacture various AAV serotypes in large quantities for pre-clinical and clinical trials. A generic and scalable method has been described in this study to efficiently produce AAV serotypes (AAV1-9) by transfection of a fully characterized cGMP HEK293SF cell line grown in suspension and serum-free medium. First, the production parameters were evaluated using AAV2 as a model serotype. Second, all nine AAV serotypes were produced successfully with yields of 1013Vg/L cell culture. Subsequently, AAV2 and AAV6 serotypes were produced in 3-L controlled bioreactors where productions yielded up to 1013Vg/L similar to the yields obtained in shake-flasks. For example, for AAV2 1013Vg/L cell culture (6.8×1011IVP/L) were measured between 48 and 64h post transfection (hpt). During this period, the average cell specific AAV2 yields of 6800Vg per cell and 460IVP per cell were obtained with a Vg to IVP ratio of less than 20. Successful operations in bioreactors demonstrated the potential for scale-up and industrialization of this generic process for manufacturing AAV serotypes efficiently. © 2013.
Keywords: adenovirus vector; butyric acid; plasmid DNA; Adeno associated virus; article; bioreactor; controlled study; culture medium; embryo; human; human cell; nonhuman; priority journal; scale up; serotype; suspension cell culture; viral gene delivery system; virogenesis; virus genome; virus infectivity

A review of catalysts for the electroreduction of carbon dioxide to produce low-carbon fuels - Qiao, J.; Liu, Y.; Hong, F.; Zhang, J. (Chemical Society Reviews, 2014)
This paper reviews recent progress made in identifying electrocatalysts for carbon dioxide (CO2) reduction to produce low-carbon fuels, including CO, HCOOH/HCOO-, CH2O, CH4, H 2C2O4/HC2O4 -, C2H4, CH3OH, CH3CH2OH and others. The electrocatalysts are classified into several categories, including metals, metal alloys, metal oxides, metal complexes, polymers/clusters, enzymes and organic molecules. The catalyts' activity, product selectivity, Faradaic efficiency, catalytic stability and reduction mechanisms during CO2 electroreduction have received detailed treatment. In particular, we review the effects of electrode potential, solution-electrolyte type and composition, temperature, pressure, and other conditions on these catalyst properties. The challenges in achieving highly active and stable CO2 reduction electrocatalysts are analyzed, and several research directions for practical applications are proposed, with the aim of mitigating performance degradation, overcoming additional challenges, and facilitating research and development in this area. This journal is © The Royal Society of Chemistry.

Evaluation of a calorimetric thermal voltage converter for RF-DC difference up to 1 GHz - Shan, Y.; Meng, Y.S.; Filipski, P.S. (IEEE Transactions on Instrumentation and Measurement, 2014)
In this paper, we present a performance evaluation of the RF-DC transfer difference for a calorimetric thermal voltage converter (CTVC) designed by the National Research Council of Canada (NRC) at frequencies up to 1 GHz. In the first part of this paper, we describe a bilateral comparison of the RF-DC difference standards between the NRC and the National Metrology Centre of the Agency for Science, Technology and Research of Singapore, in the frequency band from 1 kHz to 100 MHz. A good agreement is observed between the two laboratories using the CTVC as a traveling standard. In the second part of this paper, we evaluate the performance of the CTVC at higher frequencies up to 1 GHz. In this part, RF-DC difference of the CTVC is mathematically modeled and experimentally evaluated in terms of the calibration factor of a thermistor mount and the reflection coefficients at its type-N input connector. © 2013 IEEE.

Coiled-coil helix rotation selects repressing or activating state of transcriptional regulator DhaR - Shi, R.; McDonald, L.; Cygler, M.; Ekiel, I. (Structure, 2014)
Escherichia coli dihydroxyacetone (Dha) kinase consists of two subunits, DhaK and DhaL. Transcription of dha operon is regulated by the DhaR transcription factor and its action is under control of the kinase subunits. DhaR is activated by interaction with DhaL while it is repressed by DhaK. We have determined the structures of DhaK and DhaL bound to the tandem GAF-like and PAS domains of the DhaR, providing an architectural model for how GAF/PAS tandem domains work together in binding protein partners. The structures reveal a mechanism of opposite transcriptional regulation by the DhaK and DhaL subunits. The kinase subunits interface with DhaR through surfaces that partially overlap with their active sites, allowing sensing of ATP- versus ADP-loaded DhaL subunit and also precluding a ternary complex between DhaK-DhaL and DhaR. The rotation of helices within the DhaR coiled-coil linker upon DhaL binding provides the mechanism for transmitting the binding signal from the GAF/PAS domains to the C-terminal DNA-binding domain. © 2014 Elsevier Ltd. All rights reserved.

Discovery of the Fomalhaut C debris disc - Kennedy, G.M.; Wyatt, M.C.; Kalas, P.; Duchêne, G.; Sibthorpe, B.; Lestrade, J.-F.; Matthews, B.C.; Greaves, J. (Monthly Notices of the Royal Astronomical Society: Letters, 2014)
Fomalhaut is one of the most interesting and well-studied nearby stars, hosting at least one planet, a spectacular debris ring and two distant low-mass stellar companions (TW PsA and LP 876-10, a.k.a. Fomalhaut B and C). We observed both companions with Herschel, and while no disc was detected around the secondary, TW PsA, we have discovered the second debris disc in the Fomalhaut system, around LP 876-10. This detection is only the second case of two debris discs seen in a multiple system, both of which are relatively wide (≳3000 au for HD 223352/40 and 158 kau [0.77 pc] for Fomalhaut/LP 876-10). The disc is cool (24K) and relatively bright, with a fractional luminosity Ldisc/L*= 1.2 × 10-4, and represents the rare observation of a debris disc around an M dwarf. Further work should attempt to find if the presence of two discs in the Fomalhaut system is coincidental, perhaps simply due to the relatively young system age of 440 Myr, or if the stellar components have dynamically interacted and the system is even more complex than it currently appears. © 2013 The Authors.

Lithium ion battery applications of molybdenum disulfide (MoS2) nanocomposites - Stephenson, T.; Li, Z.; Olsen, B.; Mitlin, D. (Energy and Environmental Science, 2014)
This is the first targeted review of the synthesis-microstructure- electrochemical performance relations of MoS2-based anodes and cathodes for secondary lithium ion batteries (LIBs). Molybdenum disulfide is a highly promising material for LIBs that compensates for its intermediate insertion voltage (∼2 V vs. Li/Li+) with a high reversible capacity (up to 1290 mA h g-1) and an excellent rate capability (e.g. 554 mA h g-1 after 20 cycles at 50 C). Several themes emerge when surveying the scientific literature on the subject: first, we argue that there is excellent data to show that truly nanoscale structures, which often contain a nanodispersed carbon phase, consistently possess superior charge storage capacity and cycling performance. We provide several hypotheses regarding why the measured capacities in such architectures are well above the theoretical predictions of the known MoS2 intercalation and conversion reactions. Second, we highlight the growing microstructural and electrochemical evidence that the layered MoS2 structure does not survive past the initial lithiation cycle, and that subsequently the electrochemically active material is actually elemental sulfur. Third, we show that certain synthesis techniques are consistently demonstrated to be the most promising for battery applications, and describe these in detail. Fourth, we present our selection of synthesis methods that we believe to have a high potential for creating improved MoS 2 LIB electrodes, but are yet to be tried. This journal is © 2014 The Royal Society of Chemistry.
Keywords: Charge storage capacity; Conversion reactions; Electrochemical performance; High reversible capacities; Molybdenum disulfide; Scientific literature; Secondary lithium ion batteries; Synthesis techniques; Electrodes; Lithium batteries; Molybdenum; Molybdenum compounds; carbon; fuel cell; lithium; molybdenum; sulfur; surveying

A novel half-cell design and fabrication for an in-situ evaluation of pem fuel cell electrocatalysts - Zhang, L.; Kim, J.; Singh, S.; Tsay, K.; Zhang, J. (International Journal of Green Energy, 2014)
A novel electrochemical half-cell is designed and fabricated for in-situ evaluating both anode and cathode catalysts that mimic PEM fuel cell operating conditions. Both carbon-supported Pt and Pt0.5Ru0.5 catalysts are used to prepare the catalyst-coated membrane electrodes for this half-cell validation. A gas feeding system is constructed for quantitatively supplying of H 2, H2+CO, or O2 gases to the half-cell for measurements. CO-tolerance of the anode catalyst in hydrogen oxidation reaction (HOR) is tested using this cell. The oxygen reduction reaction (ORR) on Pt/C-coated membrane electrode is studied using this half-cell, further confirming the feasibility of this half-cell design and fabrication. It is expected that this half-cell is also useful for catalyst/catalyst layer evaluation for direct liquid fuel cells. © 2013 Copyright Taylor and Francis Group, LLC.
Keywords: CO tolerance; Electrochemical half-cell; Hydrogen oxidation reaction; Oxygen reduction reaction; PEM fuel cell; Electrocatalysts; Electrolytic reduction; Fabrication; Hydrogen; Liquid fuels; Proton exchange membrane fuel cells (PEMFC); catalyst; design; electrochemistry; electrode; fuel cell; hydrogen peroxide; in situ measurement; oxidation

Unique viscoelastic behaviors of colloidal nanocrystalline cellulose aqueous suspensions - Lu, A.; Hemraz, U.; Khalili, Z.; Boluk, Y. (Cellulose, 2014)
Unique rheological and phase behaviors of rod-like nanocrystalline cellulose (NCC) suspensions in aqueous media are revealed in the present article. Specifically, the NCC aqueous suspension remained isotropic in a wide NCC concentration range in which the suspension underwent transition from dilute solution to gel, and the relative viscosity of the NCC suspension could be well fitted by the Sato-Teramoto theory in the full concentration range tested. Correspondingly, both zero-shear viscosity and complex viscosity increased monotonically with NCC concentration, and no maximum value was observed along the curves of zero-shear viscosity or complex viscosity versus NCC concentration, indicating a deviation from the lyotropic system. However, a shear-induced birefringence phenomenon was observed, indicating the NCC suspension formed a temporary ordered structure in the external force field but was unable to form an anisotropic (liquid crystalline) phase. The Cox-Merz rule was not applicable for the NCC suspension as a result of oriented domains, i.e., rod-like NCC particles. Moreover, time-concentration superposition was successfully applied to both the storage and loss modulus, attributed to the isotropic feature of the NCC suspension in the tested concentration range. The reason why this NCC suspension remained isotropic could be because of the strong electrostatic repulsions between NCC particles and the weak tendency or driving force of anisotropy formation as a result of the small aspect ratio of NCC particles, Na+ counterions and large amounts of negative charges along the NCC particles. The results suggested that not all the rod-like particles were able to form an anisotropic phase in aqueous suspension, but dominated by various factors. © 2014 Springer Science+Business Media Dordrecht.

Unsteady laminar to turbulent flow in a spacer-filled channel - Mojab, S. M.; Pollard, A.; Pharoah, J. G.; Beale, S. B.; Hanff, E. S. (Flow, Turbulence and Combustion, 2014)
A combined numerical and experimental investigation has been carried out to study the flow behaviour in a spacer-filled channel, representative of those used in spiral-wound membrane modules. Direct numerical simulation and particle image velocimetry were used to investigate the fluid flow characteristics inside a 2 × 2 cell at Reynolds numbers that range between 100 and 1000. It was found that the flow in this geometry moves parallel to and also rotates between the spacer filaments and that the rate of rotation increases with Reynolds number. The flow mechanisms, transition process and onset of turbulence in a spacer-filled channel are investigated including the use of the velocity spectra at different Reynolds numbers. It is found that the flow is steady for Re < 200 and oscillatory at Re ∼ 250 and increasingly unsteady with further increases in Re before the onset of turbulent flow at Re ∼ 1000.
Keywords: Experimental investigations; Flow spacer; Free stream; Laminar/turbulent flow; Particle image velocimetries; Spacer-filled channels; Spiral-wound membranes; Transition; Membranes; Turbulence; Turbulent flow; Reynolds number

Experimental identification of the active sites in pyrolyzed carbon-supported cobalt-polypyrrole-4-toluenesulfinic acid as electrocatalysts for oxygen reduction reaction - Sha, H.-D.; Yuan, X.; Li, L.; Ma, Z.; Ma, Z.-F.; Zhang, L.; Zhang, J. (Journal of Power Sources, 2014)
A series of carbon supported cobalt-polypyrrole-4-toluenesulfinic acid have been pyrolyzed in an argon atmosphere at 800 C, then structurally characterized and electrochemically evaluated as oxygen reduction reaction (ORR) catalysts in aqueous 0.5 M sulfuric acid. The structures are cobalt bonded to nitrogen species (Co-Nx) along with metallic cobalt and cobalt oxide. When the cobalt loading in the compound is less than 1.0 wt%, the predominate form is Co-Nx, when the loading is higher than 1.0 wt%, metallic Co and Co oxide particles co-exist with the Co-Nx compound. At a Co loading of ∼1.0 wt%, the catalyst gives the best ORR activity. Both metallic Co and Co oxide are not active for catalyzing ORR, and block the catalytically active Co-Nx species from the surface and reduce the catalytic activity since the diffusion limiting current density on a rotating disk electrode (RDE) increases when the electrode blocking agents are washed away with acid. © 2014 Elsevier B.V. All rights reserved.

Characterization of pore network structure in catalyst layers of polymer electrolyte fuel cells - El Hannach, Mohamed; Soboleva, Tatyana; Malek, Kourosh; Franco, Alejandro A.; Prat, Marc; Pauchet, Joël; Holdcroft, Steven (Journal of Power Sources, 2014)
We model and validate the effect of ionomer content and Pt nanoparticles on nanoporous structure of catalyst layers in polymer electrolyte fuel cells. By employing Pore network modeling technique and analytical solutions, we analyze and reproduce experimental N2-adsorption isotherms of carbon, Pt/carbon and catalyst layers with various ionomer contents. The porous catalyst layer structures comprise of Ketjen Black carbon, Pt and Nafion ionomer. The experimental pore size distributions obtained by N2-adsorption are used as an input to generate porous media using the pore network approach. Subsequently, the simulated porous structures are used to produce simulated N2-adsorption isotherms, which are then compared to the experimentally measured isotherms. The results show a good agreement in the prediction of the effect of the ionomer content on the microstructure of catalyst layers. Moreover, the analysis of the isotherms confirms the hypothesis of ionomer distribution on the surface of agglomerates as well as the existence of different sorption regimes in primary and secondary pores of fuel cell catalyst layers.
Keywords: Catalyst layers; Fuel-cell catalyst layers; Nanoporous structures; Nitrogen adsorption isotherm; Polymer electrolyte fuel cells; Pore-network modeling; Porous catalysts; Porous structures; Adsorption isotherms; Fuel cells; Ionomers; Platinum; Polyacrylonitriles; Polyelectrolytes; Polymers; Pore size; Porous materials; Catalysts

Modeling study of liquid impingement erosion of NiAl alloy - Zhao, J.; Chen, K.; Liu, R.; Liang, M. (Wear, 2014)
This article presents the theoretical modeling and computation of liquid impingement erosion of solid metallic surface and the response mechanisms, with special interest in study of the liquid impingement erosion behavior of NiAl alloy. Particular attention is paid to investigating the effects of drop velocity and drop size on the damage of the target surface and to predicting and simulating the erosive failures. The models of impact stress wave, mean depth of penetration, and maximum depth of erosion rate (Max DER) are employed to develop various maps for NiAl alloy, including target thickness vs. drop size (diameter), rate of mean depth of penetration (MDRP) vs. drop impact velocity, and damage threshold velocity (DTV) vs. drop size. For comparison, pure Ni target and steel ball erodent are also studied. The computational results are analyzed and discussed. © 2014 Elsevier B.V.

Hyperspectral multimodal CARS microscopy in the fingerprint region - Pegoraro, A.F.; Slepkov, A.D.; Ridsdale, A.; Moffatt, D.J.; Stolow, A. (Journal of Biophotonics, 2014)
A simple scheme for multimodal coherent anti-Stokes Raman scattering (CARS) microscopy is based on the spectral focusing of ultrafast-oscillator-derived pump/probe light and synchronous photonic crystal fiber (PCF) fiber-generated broadband Stokes light. To date, such schemes allowed rapid hyperspectral imaging throughout the CH/OH high frequency region (2700-4000 cm-1). Here we extend this approach to the middle (1640-3300 cm-1) and fingerprint regions (850-1800 cm-1) of the Raman spectrum. Our simple integrated approach to rapid hyperspectral CARS microscopy in the fingerprint region is demonstrated by applications to label-free multimodal imaging of cellulose and bulk bone, including use of the phosphate resonance at 960 cm-1. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compensation of piezoceramic bonding layer degradation for structural health monitoring - Mulligan, K.R.; Quaegebeur, N.; Masson, P.; Brault, L.-P.; Yang, C. (Structural Health Monitoring, 2014)
The compensation of the degradation of the bonding layer of piezoceramics used in structural health monitoring is addressed in this article. A simple admittance model is first used to measure and extract the variation of admittance parameters using the same acquisition chain which is used by the structural health monitoring system for damage monitoring. More precisely, the method uses measurable changes in physical transducer modal damping at frequencies around piezoceramic resonance to estimate the extent of degradation. Then, a finite element model is used to obtain calibration curves linking the variations in transducer modal damping to amplitude and phase of the ultrasonic signals generated or measured by the piezoceramics. Such calibration curves are obtained by simulating with the FEM the effect of varying the bonding layer coverage area and Young's modulus on (a) admittance and (b) amplitude and phase of the ultrasonic signals. From this, a signal correction factor is developed for the dominant bonding layer coverage area degradation failure mode to compensate for the changes in amplitude and phase of guided waves generated and measured by degraded piezoceramic transducers. The measured modal damping determines the amount of bonding layer degradation from the simulated modal damping calibration curves and then the quantified bonding layer degradation amount selects the amplitude and phase correction to be applied to measured signals from the calibration curves. The benefits of the signal correction factor are demonstrated below piezoceramic resonance to improve damage imaging and localization using the Embedded Ultrasonic Structural Radar algorithm (delay and sum method) when a single transducer in a sparse array of transducers fixed to an aluminum plate is damaged due to the close proximity of drop-weight impacts. Up to a certain damage extent, the signal correction factor could allow an extension of the service life of the structural health monitoring system. © The Author(s) 2013.

Formation of Cu nanostructured electrode surfaces by an annealing-electroreduction procedure to achieve high-efficiency CO2 electroreduction - Qiao, J.; Jiang, P.; Liu, J.; Zhang, J. (Electrochemistry Communications, 2014)
An effective fibrous Cu electrode surface, created using a procedure combining high-temperature annealing and electroreduction, is explored for CO2 reduction to produce useful fuels. The nanostructure of this Cu electrode surface contains a layer of nanofibers or nanofibers surrounded by kernels with 30-100 nm diameters. With a specific surface area as high as 458 cm2 per geometric electrode surface area, this nanostructured electrode is found to have a high activity toward CO2 reduction, indicated by its more positive reduction potentials and higher catalytic current density than a smooth Cu electrode. The Faradaic efficiency for HCOO - production is 43%, and the electrode surface remains stable during 19 h of electrolysis - better results than with smooth Cu under identical conditions. © 2013 Elsevier B.V.
Keywords: Cu electrode; Electro reduction; Electrode surface area; Faradaic efficiencies; High-temperature annealing; Hybrid nanofiber; Nano-structured electrodes; Nanostructured electrode surfaces; Electrocatalysts; Electrolytic reduction; Nanofibers; Carbon dioxide

Electrocatalytically active nickel-based electrode coatings formed by atmospheric and suspension plasma spraying - Aghasibeig, M.; Moreau, C.; Wuthrich, R.; Mousavi, M.; Ettouill, Ben F.; Dolatabadi, A. (Journal of thermal spray technology, 2014)
Ni-based electrode coatings with enhanced surface areas, for hydrogen production, were developed using atmospheric plasma spray (APS) and suspension plasma spray (SPS) processes. The results revealed a larger electrochemical active surface area for the coatings produced by SPS compared to those produced by APS process. SEM micrographs showed that the surface microstructure of the sample with the largest surface area was composed of a large number of small cauliflower-like aggregates with an average diameter of 10 μm.

Characterization and properties of Alkali treated flax - Hu, W.; Ton-That, M.T. (Applied Mechanics and Materials, 2014)
Flax, a kind of natural fiber, has been widely applied as reinforcing materials for polymer composites because of its superior tensile properties. It normally contains noncellulose portions and other impurities, which could act as stress concentration regions to affect negatively the mechanical properties of composites. In this work, canadian linseed flax (F1) was treated by alkali to remove the noncellulose portions and impurities. The treated F1 was characterized in detail applying SEM, FTIR, TGA and single fiber tensile test for its promising application in composites as natural materials. The proper condition of alkali treatment was explored and determined to be 2% of NaOH for 1h at 80°C. Under this condition, the mechanical property of the fiber was 10% better than that of untreated F1, and the non-cellulose portion removing ratio was more than 25% without hurting fiber structure. © (2014) Trans Tech Publications, Switzerland.
Keywords: Alkali treatment; Concentration region; Fiber structures; Natural materials; Polymer composite; Properties of composites; Reinforcing materials; Single fiber; Characterization; Environmental technology; Fibers; Flax; Linen; Mechanical properties; Removal; Stress concentration; Tensile testing; Yarn

The small numbers of large Kuiper belt objects - Schwamb, M.E.; Brown, M.E.; Fraser, W.C. (Astronomical Journal, 2014)
We explore the brightness distribution of the largest and brightest (m(R) < 22) Kuiper Belt Objects (KBOs). We construct a luminosity function of the dynamically excited or hot Kuiper Belt (orbits with inclinations >5°) from the very brightest to m(R) = 23. We find for m(R) ≲ 23, a single slope appears to describe the luminosity function. We estimate that 2 KBOs brighter than m(R)19.5 are present in the Kuiper Belt today. With nine bodies already discovered this suggests that the inventory of bright KBOs is nearly complete. © 2014. The American Astronomical Society. All rights reserved..

Practical correlation for thermal resistance of low-sloped enclosed airspaces with downward heat flow for building applications - Saber, H.H. (HVAC and R Research, 2014)
The 2009 ASHRAE Handbook - Fundamentals (Chapter 26) provided a table that contains the thermal resistances (R-values) of vertical, horizontal, and high-sloped (45°) enclosed airspaces. This table is extensively used by modelers, architects, and building designers in the design for the R-values of building enclosures. The effect of the airspace aspect ratio and the inclination angle (θ) of 30° on the R-values are not accounted for in the ASHRAE table. However, previous studies showed that the aspect ratio of the airspace can affect its R-value. In this article, the previous studies that focused on determining the R-values for vertical, horizontal, and high-sloped enclosed airspaces are extended to investigate the effect of the aspect ratio on the R-values of low-sloped (θ = 30°) enclosed airspaces under downward heat flow for different airspace thicknesses and having a wide range of values for the effective emittance, mean temperature, and temperature differences across the airspaces. Thereafter, practical correlation is developed for determining the R-values of low-sloped enclosed airspaces for future use by modelers, architects, and building designers.

Pressure-induced changes on the electronic structure and electron topology in the direct FCC → SH transformation of silicon - Tse, J.S.; Hanfland, M.; Flacau, R.; Desgreniers, S.; Li, Z.; Mende, K.; Gilmore, K.; Nyrow, A.; Moretti Sala, M.; Sternemann, C. (The Journal of Physical Chemistry C, 2014)
X-ray diffraction experiments at 80 K show that when silicon is compressed under hydrostatic conditions the intermediate high-pressure phases are bypassed leading to a direct transformation to the simple hexagonal structure at 17 GPa. A maximum entropy analysis of the diffraction patterns reveals dramatic alterations in the valence electron distribution from tetrahedral covalent bonding to localization in the interstitial sites and along the one-dimensional silicon atom chain running along adjacent hexagonal layers. Changes in the orbital character of the unoccupied states are confirmed using X-ray Raman scattering spectroscopy and theoretical Bethe-Salpeter equation calculations. This is the first direct observation indicating that the silicon valence electrons in 3s and 3p orbitals are transferred to the 3d orbitals at high density which proves that electrons of compressed elemental solids migrate from their native bonding configuration to interstitial regions. © 2013 American Chemical Society.

Analysis of cellulose nanocrystal rod lengths by dynamic light scattering and electron microscopy - Boluk, Y.; Danumah, C. (Journal of Nanoparticle Research, 2014)
A method to characterize the length (L) of rod-like cellulose nanocrystal (CNC) particles is described. It is based on dynamic light scattering (DLS) and electron microscopy. Measurement of translational diffusion coefficient from DLS along with diameter measurements from electron microscopy is used in Broersma translational diffusion coefficient equation to calculate the CNC particle L. For wood based CNC rods, diameter of 15 nm measured by scanning electron microscopy (SEM) and translational diffusion coefficient of 5.21 × 10 -12 m2/s measured by DLS give particle L of 271 nm from Broersma's relation. This one and other calculated L values for various rod-like particles are in good agreement with the L of the particles measured either by transmission or SEM. © 2013 Springer Science+Business Media Dordrecht.

Antibody light chain variable domains and their biophysically improved versions for human immunotherapy - Kim, D.Y.; To, R.; Kandalaft, H.; Ding, W.; Van Faassen, H.; Luo, Y.; Schrag, J.D.; St-Amant, N.; Hefford, M.; Hirama, T.; Kelly, J.F.; MacKenzie, R.; et al. (mAbs, 2014)
We set out to gain deeper insight into the potential of antibody light chain variable domains (VLs) as immunotherapeutics. To this end, we generated a naïve human VL phage display library and, by using a method previously shown to select for non-aggregating antibody heavy chain variable domains (VHs), we isolated a diversity of VL domains by panning the library against B cell super-antigen protein L. Eight domains representing different germline origins were shown to be non-aggregating at concentrations as high as 450 μM, indicating VL repertoires are a rich source of nonaggregating domains. In addition, the VLs demonstrated high expression yields in E. coli, protein L binding and high reversibility of thermal unfolding. A side-by-side comparison with a set of non-aggregating human VHs revealed that the VLs had similar overall profiles with respect to melting temperature (Tm), reversibility of thermal unfolding and resistance to gastrointestinal proteases. Successful engineering of a non-canonical disulfide linkage in the core of VLs did not compromise the non-aggregation state or protein L binding properties. Furthermore, the introduced disulfide bond significantly increased their Tms, by 5.5-17.5 °C, and pepsin resistance, although it somewhat reduced expression yields and subtly changed the structure of VLs. Human VLs and engineered versions may make suitable therapeutics due to their desirable biophysical features. The disulfide linkage-engineered VLs may be the preferred therapeutic format because of their higher stability, especially for oral therapy applications that necessitate high resistance to the stomach's acidic pH and pepsin. © 2014 Landes Bioscience.

Microwave-assisted retting and optimization of the process through chemical composition analysis of the matrix - Nair, G.R.; Kurian, J.; Yaylayan, V.; Rho, D.; Lyew, D.; Raghavan, G.S.V. (Industrial Crops and Products, 2014)
Pre-soaked flax stems were subjected to microwave assisted retting at different power levels and the effectiveness of microwave assisted retting was studied through the analysis of chemical compounds presented in the retted flax fibers processed from the stems. Response surface statistical design was used for this study with JMP® 10 software. Chemical analyses were performed by gravimetric methods to find out percentage of compounds. Cellulose, hemicellulose, lignin and pectin concentrations and the sugar content in the solution obtained after the treatment were subjected to analysis. Cellulose percentage in the fiber was increased significantly (p<0.0001) with the increase of microwave power at various soaking levels, which proved the release of cellulosic fiber with the application of microwave energy during retting. Hemicellulose, lignin and pectin concentrations decreased significantly after microwave-assisted retting which explained higher degree of retting after the treatment. This study noted change in chemical composition of the fibers, which can be used as a tool to estimate the effectiveness of microwave-assisted retting and the results could lead to optimization of the process. © 2013 Elsevier B.V.
Keywords: Bioprocesses; Chemical composition analysis; Chemical compositions; Flax fiber; Gravimetric methods; Microwave-assisted; Pectin concentration; Retting; Cellulose; Chemical analysis; Flax; Lignin; Linen; Microwaves; Optimization; Yarn; Fibers; cellulose; chemical composition; concentration (composition); lignin; microwave radiation; plant product; polysaccharide; processing; stem

A modified captive bubble method for determining advancing and receding contact angles - Xue, J.; Shi, P.; Zhu, L.; Ding, J.; Chen, Q.; Wang, Q. (Applied Surface Science, 2014)
In this work, a modification to the captive bubble method was proposed to test the advancing and receding contact angle. This modification is done by adding a pressure chamber with a pressure control system to the original experimental system equipped with an optical angle mater equipped with a high speed CCD camera, a temperature control system and a computer. A series of samples with highly hydrophilic, hydrophilic, hydrophobic and superhydrophobic surfaces were prepared. The advancing and receding contact angles of these samples with highly hydrophilic, hydrophilic, and hydrophobic surfaces through the new methods was comparable to the result tested by the traditional sessile drop method. It is proved that this method overcomes the limitation of the traditional captive bubble method and the modified captive bubble method allows a smaller error from the test. However, due to the nature of the captive bubble technique, this method is also only suitable for testing the surface with advancing or receding contact angle below 130°. © 2014 Elsevier B.V. All rights reserved.

Model testing of a series of bi-directional tidal turbine rotors - Liu, Penfei; Bose, Neil; Frost, Rowan; Macfarlane, Gregor; Lilienthal, Tim; Penesis, Irene; Windsor, Fraser; Thomas, Giles (Energy, 2014)
A series of 7 bi-directional tidal turbine metal rotor models were manufactured and tested. A rotor testing apparatus was built using an off-the-shelf propeller dynamometer. Configuration, testing set-up, calibration of the apparatus and data acquisition details are described. Influences of Reynolds number, pitch ratio, pitch distribution and solidity, on hydrodynamic performance, were made and are presented. In addition to other findings, a rotor with a solidity of 0.4 produced the highest power output. The increase in power coefficient from a solidity of 0.2 to 0.4 and 0.6 to 0.4, is 14% and 16%, respectively. This indicates that for this kind of bi-directional turbine, a relatively larger solidity of about 0.4 than most installed turbine rotors maybe a better choice in terms of power output.
Keywords: Rotor testing; Bi-directional turbine; HATT; HACT

Effect of peptide secondary structure on adsorption and adsorbed film properties on end-grafted polyethylene oxide layers - Binazadeh, M.; Zeng, H.; Unsworth, L.D. (Acta Biomaterialia, 2014)
Poly-l-lysine (PLL), in α-helix or β-sheet configuration, was used as a model peptide for investigating the effect of secondary structures on adsorption events to poly(ethylene oxide) (PEO) modified surfaces formed using θ solvents. Circular dichroism results showed that the secondary structure of PLL persisted upon adsorption to Au and PEO modified Au surfaces. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize the chemisorbed PEO layer in different solvents (θ and good solvents), as well as the sequential adsorption of PLL in different secondary structures (α-helix or β-sheet). QCM-D results suggest that chemisorption of PEO 750 and 2000 from θ solutions led to brushes 3.8 ± 0.1 and 4.5 ± 0.1 nm thick with layer viscosities of 9.2 ± 0.8 and 4.8 ± 0.5 cP, respectively. The average number of H2O per ethylene oxides, while in θ solvent, was determined as ∼0.9 and ∼1.2 for the PEO 750 and 2000 layers, respectively. Upon immersion in good solvent (as used for PLL adsorption experiments), the number of H2O per ethylene oxides increased to ∼1.5 and ∼2.0 for PEO 750 and 2000 films, respectively. PLL adsorbed masses for α-helix and β-sheet on Au sensors was 231 ± 5 and 1087 ± 14 ng cm-2, with layer viscosities of 2.3 ± 0.1 and 1.2 ± 0.1 cP, respectively; suggesting that the α-helix layer was more rigid, despite a smaller adsorbed mass, than that of β-sheet layers. The PEO 750 layer reduced PLL adsorbed amounts to ∼10 and 12% of that on Au for α-helices and β-sheets respectively. The PLL adsorbed mass to PEO 2000 layers dropped to ∼12% and 4% of that on Au, for α-helix and β-sheet respectively. No significant differences existed for the viscosities of adsorbed α-helix and β-sheet PLL on PEO surfaces. These results provide new insights into the fundamental understanding of the effects of secondary structures of peptides and proteins on their surface adsorption. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Keywords: biomaterial; gold; macrogol; peptide; polylysine; protein; solvent; water; adsorption; article; circular dichroism; film; material coating; peptide analysis; priority journal; protein adsorption; protein secondary structure; quartz crystal microbalance; sensor; thickness; viscosity

Majority carrier transport in single crystal rutile nanowire arrays - Mohammadpour, A.; Farsinezhad, S.; Wiltshire, B.D.; Shankar, K. (Physica Status Solidi - Rapid Research Letters, 2014)
Monocrystalline n-TiO2 nanowires of the rutile phase (Rtl-NWs) grown by a scalable hydrothermal method constitute a functional oxide nanomaterial with potential applications in photovoltaics, photocatalysts, field emitters and electrochemical battery anodes. Carrier transport in Rtl-NWs is of fundamental importance but has hitherto been inferred indirectly via impedance and intensity-modulated spectroscopic techniques. We report an effective electron drift mobility of 1.95 × 10-5 cm2 V-1 s-1 in rutile nanowire arrays directly measured using the time-of-flight (TOF) and space charge limited current techniques. In addition, we measure an equilibrium free electron concentration of ∼1014 cm-3 and a trap density of 3.5 × 1016 cm-3 in rutile nanowires. These results point to the importance of reducing traps to improve charge transport in rutile nanowires. Transient photocurrents in rutile nanowires. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advances in coupling microfluidic chips to mass spectrometry - Feng, Xiaojun; Liu, Bi-Feng; Li, Jianjun; Liu, Xin (Mass Spectrometry Reviews, 2014)
Microfluidic technology has shown advantages of low sample consumption, reduced analysis time, high throughput, and potential for integration and automation. Coupling microfluidic chips to mass spectrometry (Chip-MS) can greatly improve the overall analytical performance of MS-based approaches and expand their potential applications. In this article, we review the advances of Chip-MS in the past decade, covering innovations in microchip fabrication, microchips coupled to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization (MALDI)-MS. Development of integrated microfluidic systems for automated MS analysis will be further documented, as well as recent applications of Chip-MS in proteomics, metabolomics, cell analysis, and clinical diagnosis.

Analytical modeling of solid-particle erosion of Stellite alloys in combination with experimental investigation - Nsoesie, S.; Liu, R.; Chen, K.Y.; Yao, M.X. (Wear, 2014)
This article presents the analytical modeling of erosion behavior of Stellite alloys under solid-particle impact. The erosion rates of five selected Stellite alloys, which are currently or potentially applied in an environment condition involving erosion, are investigated experimentally at two particle impact velocities of 84 and 98ms-1, and at two impingement angles of 30° and 90°. The Sheldon-Kanhere (S-K) model that utilizes the indentation hardness theory to derive a particle penetration equation is modified to fit the experimental data of Stellite alloys. The most significant improvement of this modified model is to include the effect of particle impingement angle. This introduces two parameters in the model, which are determined by fitting the experimental data of the five Stellite alloys. With this modified model, for Stellite alloys that have similar chemical compositions to the alloys studied in this research, the erosion rates at the particle impact velocity of 84ms-1 or 98ms-1 can be predicted for any particle impingement angles less than 30°. The limitations of this model are discussed. © 2013 Elsevier B.V.
Keywords: Chemical compositions; Environment conditions; Erosion rates; Experimental investigations; Indentation hardness; Particle impact velocities; Particle impinging; Stellite alloy; Analytical models; Erosion; Models; Stellite; Alloys

Performance of Carboxydothermus hydrogenoformans in a gas-lift reactor for syngas upgrading into hydrogen - Haddad, M.; Cimpoia, R.; Guiot, S.R. (International Journal of Hydrogen Energy, 2014)
The conversion of carbon monoxide (CO) into hydrogen (H2) by a Carboxydothermus hydrogenoformans pure culture was investigated and optimized in a 35 L gas-lift reactor. The reactor was operated with a continuous supply of gas for 3 months. Reactor performance was evaluated under various operational conditions, such as gas recirculation rates (0.3 and 1.5 L min-1), CO feeding rates (from 0.05 to 0.46 mol L-1 reactor day-1) and bacto-peptone addition to the medium. Overall, the H2 yields were constant at 95 ± 1% and 82 ± 1% (molH2 {dot operator} molCO - 1) with growth supported by peptone and unsupported respectively, regardless of the operational conditions tested. At the highest biomass density, a maximum CO conversion activity of 0.17 molCO L-1 reactor day-1 or 3.79 LCO L-1 reactor day-1 was achieved. The ratio of gas recirculation over CO feed flow rates (QR:Qin) was the major parameter that impacted both biological activity and volumetric gas-liquid mass transfer. The CO conversion performance of the gas-lift reactor was kinetically limited over a QR:Qin ratio of 40, and mass transfer limited below that ratio, resulting in a maximum conversion efficiency of 90.4 ± 0.3% and a biological activity of 2.7 ± 0.4 molCO g-1 VSS day-1. Overall, the CO conversion performance in the gas-lift reactor was limited by a low cell density, typical of C. hydrogenoformans planktonic growth. This limitation was found to be the most restrictive factor for higher CO loading rates. Crown Copyright © 2013.

Use of Fourier-transform infrared spectroscopy to quantify immunoglobulin g concentrations in alpaca serum - Burns, J.; Hou, S.; Riley, C.B.; Shaw, R.A.; Jewett, N.; Mcclure, J.T. (Journal of Veterinary Internal Medicine, 2014)
Background: Rapid, economical, and quantitative assays for measurement of camelid serum immunoglobulin G (IgG) are limited. In camelids, failure of transfer of maternal immunoglobulins has a reported prevalence of up to 20.5%. An accurate method for quantifying serum IgG concentrations is required. Objective: To develop an infrared spectroscopy-based assay for measurement of alpaca serum IgG and compare its performance to the reference standard radial immunodiffusion (RID) assay. Animals: One hundred and seventy-five privately owned, healthy alpacas. Methods: Eighty-two serum samples were collected as convenience samples during routine herd visits whereas 93 samples were recruited from a separate study. Serum IgG concentrations were determined by RID assays and midinfrared spectra were collected for each sample. Fifty samples were set aside as the test set and the remaining 125 training samples were employed to build a calibration model using partial least squares (PLS) regression with Monte Carlo cross validation to determine the optimum number of PLS factors. The predictive performance of the calibration model was evaluated by the test set. Results: Correlation coefficients for the IR-based assay were 0.93 and 0.87, respectively, for the entire data set and test set. Sensitivity in the diagnosis of failure of transfer of passive immunity (FTPI) ([IgG] <1,000 mg/dL) was 71.4% and specificity was 100% for the IR-based method (test set) as gauged relative to the RID reference method assay. Conclusions and Clinical Importance: This study indicated that infrared spectroscopy, in combination with chemometrics, is an effective method for measurement of IgG in alpaca serum. © 2014 by the American College of Veterinary Internal Medicine.

Prospective study of acute health effects in relation to exposure to cyanobacteria - Lévesque, B.; Gervais, M.-C.; Chevalier, P.; Gauvin, D.; Anassour-Laouan-Sidi, E.; Gingras, S.; Fortin, N.; Brisson, G.; Greer, C.; Bird, D. (Science of the Total Environment, 2014)
We conducted a study to investigate the relationship between exposure to cyanobacteria and microcystins and the incidence of symptoms in humans living in close proximity to lakes affected by cyanobacteria. The design was a prospective study of residents living around three lakes (Canada), one of which has a water treatment plant supplying potable water to local residents. Participants had to keep a daily journal of symptoms and record contact (full or limited) with the water body. Samples were collected to document cyanobacteria and microcystin concentrations. Symptoms potentially associated with cyanobacteria (gastrointestinal: 2 indices (GI1: diarrhea or abdominal pain or nausea or vomiting; GI2: diarrhea or vomiting or [nausea and fever] or [abdominal cramps and fever]); upper and lower respiratory tract; eye; ear; skin; muscle pain; headaches; mouth ulcers) were examined in relation with exposure to cyanobacteria and microcystin by using Poisson regression. Only gastrointestinal symptoms were associated with recreational contact. Globally, there was a significant increase in adjusted relative risk (RR) with higher cyanobacterial cell counts for GI2 (<. 20,000. cells/mL: RR = 1.52, 95% CI = 0.65-3.51; 20,000-100,000. cells/mL: RR = 2.71, 95% CI = 1.02-7.16; >. 100,000. cells/mL: RR = 3.28, 95% CI = 1.69-6.37, p-trend. =. 0.001). In participants who received their drinking water supply from a plant whose source was contaminated by cyanobacteria, an increase in muscle pain (RR = 5.16; 95% CI = 2.93-9.07) and gastrointestinal (GI1: RR = 3.87; 95% CI = 1.62-9.21; GI2: RR = 2.84; 95% CI = 0.82-9.79), skin (RR = 2.65; 95% CI = 1.09-6.44) and ear symptoms (RR = 6.10; 95% CI = 2.48-15.03) was observed. The population should be made aware of the risks of gastrointestinal symptoms associated with contact (full or limited) with cyanobacteria. A risk management plan is needed for water treatment plants that draw their water from a source contaminated with cyanobacteria. © 2013 Elsevier B.V.
Keywords: Bathing; Cyanobacteria; Cyanobacterial cells; Gastrointestinal symptoms; Microcystins; Poisson regression; Recreational water; Risk management plans; Lakes; Muscle; Potable water; Risk management; Toxic materials; Water treatment plants; Health; drinking water; microcystin; bathing water; cyanobacterium; disease prevalence; health risk; lake water; symptom; water treatment; abdominal cramp; abdominal pain; article; bacterial count; bacterium contamination; Canada; concentration (parameters); cyanobacterium; diarrhea; ear disease; eye; fever; gastrointestinal symptom; headache; health hazard; human; lake; mouth ulcer; myalgia; nausea; nonhuman; planning; priority journal; prospective study; recreation; respiratory system; risk assessment; risk management; skin disease; symptom; vomiting; water contamination; water treatment; Canada

Mechanistic insights into the effect of nanoparticles on zebrafish hatch - Ong, K.J.; Zhao, X.; Thistle, M.E.; Maccormack, T.J.; Clark, R.J.; Ma, G.; Martinez-Rubi, Y.; Simard, B.; Loo, J.S.C.; Veinot, J.G.C.; Goss, G.G. (Nanotoxicology, 2014)
Aquatic organisms are susceptible to waterborne nanoparticles (NP) and there is only limited understanding of the mechanisms by which these emerging contaminants may affect biological processes. This study used silicon (nSi), cadmium selenide (nCdSe), silver (nAg) and zinc NPs (nZnO) as well as single-walled carbon nanotubes (SWCNT) to assess NP effects on zebrafish (Danio rerio) hatch. Exposure of 10 mg/L nAg and nCdSe delayed zebrafish hatch and 100 mg/L of nCdSe as well as 10 and 100 mg/L of uncoated nZnO completely inhibited hatch and the embryos died within the chorion. Both the morphology and the movement of the embryos were not affected, and it was determined that the main mechanism of hatch inhibition by NPs is likely through the interaction of NPs with the zebrafish hatching enzyme. Furthermore, it was concluded that the observed effects arose from the NPs themselves and not their dissolved metal components. © 2014 Informa UK, Ltd.
Keywords: cadmium selenide; nanoparticle; proteinase; silicon derivative; silicon nanoparticle; silver nanoparticle; single walled nanotube; unclassified drug; zinc nanoparticle; zinc oxide; article; chorion; controlled study; embryo; embryo development; enzyme activity; enzyme inhibition; hatching; hydrodynamics; morphology; nonhuman; priority journal; zebra fish; zeta potential

Partial spin ordering and complex magnetic structure in BaYFeO₄ : a neutron diffraction and high temperature susceptibility study - Thompson, Corey M.; Greedan, John E.; Garlea, V. Ovidiu; Flacau, Roxana; Tan, Malinda; Nguyen, Phuong-Hieu T.; Wrobel, Friederike; Derakhshan, Shahab (Inorganic Chemistry, 2014)
The novel iron-based compound, BaYFeO₄, crystallizes in the Pnma space group with two distinct Fe³⁺ sites, that are alternately corner-shared [FeO₅]⁷⁻ square pyramids and [FeO₆]⁹⁻ octahedra, forming into [Fe₄O₁₈]²⁴⁻ rings, which propagate as columns along the b-axis. A recent report shows two discernible antiferromagnetic (AFM) transitions at 36 and 48 K in the susceptibility, yet heat capacity measurements reveal no magnetic phase transitions at these temperatures. An upturn in the magnetic susceptibility measurements up to 400 K suggests the presence of short-range magnetic behavior at higher temperatures. In this Article, variable-temperature neutron powder diffraction and high-temperature magnetic susceptibility measurements were performed to clarify the magnetic behavior. Neutron powder diffraction confirmed that the two magnetic transitions observed at 36 and 48 K are due to long-range magnetic order. Below 48 K, the magnetic structure was determined as a spin-density wave (SDW) with a propagation vector, k = (0, 0, 1/3), and the moments along the b-axis, whereas the structure becomes an incommensurate cycloid [k = (0, 0, ∼0.35)] below 36 K with the moments within the bc-plane. However, for both cases the ordered moments on Fe3+ are only of the order ∼3.0 μB, smaller than the expected values near 4.5 μB, indicating that significant components of the Fe moments remain paramagnetic to the lowest temperature studied, 6 K. Moreover, new high-temperature magnetic susceptibility measurements revealed a peak maximum at ∼550 K indicative of short-range spin correlations. It is postulated that most of the magnetic entropy is thus removed at high temperatures which could explain the absence of heat capacity anomalies at the long-range ordering temperatures. Published spin dimer calculations, which appear to suggest a k = (0, 0, 0) magnetic structure, and allow for neither low dimensionality nor geometric frustration, are inadequate to explain the observed complex magnetic structure.

On some aspects of the wheel/rail interaction - Magel, E. E.; Liu, Y. (Wear, 2014)
Problems in tribology and contact mechanics are becoming increasingly amenable to solution through models and simulation. But in application to the wheel/rail contact, there remain a number of very important features for which either gross simplifications or a lack of understanding or ability severely limits the success of those efforts. Examples include models of friction and material response (including damage functions). This paper examines a rather eclectic mix of wheel/rail factors with the goal of encouraging researchers to begin tackling and eradicating some of the bigger problem areas that remain in wheel-rail interaction modeling and to consider more rigorous implementation of real world conditions in simulations. Crown Copyright © 2013.

Overlapping and distinct roles of aspergillus fumigatus UDP-glucose 4-epimerases in galactose metabolism and the synthesis of galactose-containing cell wall polysaccharides - Lee, M.J.; Gravelat, F.N.; Cerone, R.P.; Baptista, S.D.; Campoli, P.V.; Choe, S.-I.; Kravtsov, I.; Vinogradov, E.; Creuzenet, C.; Liu, H.; Berghuis, A.M.; Latgé, J.P.; et al. (Journal of Biological Chemistry, 2014)
The cell wall of Aspergillus fumigatus contains two galactose-containing polysaccharides, galactomannan and galactosaminogalactan, whose biosynthetic pathways are not well understood. The A. fumigatus genome contains three genes encoding putative UDP-glucose 4-epimerases, uge3, uge4, and uge5. We undertook this study to elucidate the function of these epimerases. We found that uge4 is minimally expressed and is not required for the synthesis of galactose-containing exopolysaccharides or galactose metabolism. Uge5 is the dominant UDP glucose 4-epimerase in A. fumigatus and is essential for normal growth in galactose-based medium. Uge5 is required for synthesis of the galactofuranose (Galf) component of galactomannan and contributes galactose to the synthesis of galactosaminogalactan. Uge3 can mediate production of both UDP-galactose and UDP-N-acetylgalactosamine (GalNAc) and is required for the production of galactosaminogalactan but not galactomannan. In the absence of Uge5, Uge3 activity is sufficient for growth on galactose and the synthesis of galactosaminogalactan containing lower levels of galactose but not the synthesis of Galf. A double deletion of uge5 and uge3 blocked growth on galactose and synthesis of both Galf and galactosaminogalactan. This study is the first survey of glucose epimerases in A. fumigatus and contributes to our understanding of the role of these enzymes in metabolism and cell wall synthesis. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Fieldwork with vulnerable populations: Ethical implications for humancomputer interaction research - Munteanu, C.; Molyneaux, H.; O'Donnell, S. (Interactions, 2014)
The article focuses on the ethical challenges in developing and evaluating a mobile support application to assist low literacy adults. The literacy program is for adults who completed only a few years of formal schooling and can carry out some non-complex reading and writing tasks, such as some newspaper reading and writing a very simple letter. A routine ethical expectation is that participant privacy and confidentiality are guaranteed, particularly for research involving vulnerable user groups. However, it was difficult to conduct our study while fully ensuring confidentiality. In the classroom, participants openly discussed the study details and their use of the application both when researchers were present and at other times. Ethical guidelines exist for consent forms for studies involving group interactions in which participants are explicitly informed about decreased privacy, but our protocol was not designed for this situation.
Keywords: Ethical implications; Group interaction; Human-computer interaction researches; Low literacies; Mobile supports; Newspaper reading; User groups; Research; Philosophical aspects

Gems in the outer galaxy: Near-infrared imaging of three young clusters at large galactic radii - Davidge, T.J. (The Astrophysical Journal, 2014)
Images recorded with the Gemini South Adaptive Optics Imager (GSAOI) and corrected for atmospheric seeing by the Gemini Multi-conjugate Adaptive Optics System are used to investigate the stellar contents of the young outer Galactic disk clusters Haffner 17, NGC 2401, and NGC 3105. Ages estimated from the faint end of the main sequence (MS) and the ridgeline of the pre-main sequence on the (K, J-K) color-magnitude diagrams are consistent with published values that are based on the MS turnoff, with the GSAOI data favoring the younger end of the age range for NGC 2401 in the literature. The mass function (MF) of NGC 2401 is similar to that in the solar neighborhood, and stars spanning a wide range of masses in this cluster have similar clustering properties on the sky. It is concluded that NGC 2401 is not evolved dynamically. In contrast, the MF of Haffner 17 differs significantly from that in the solar neighborhood over all masses covered by these data, while the MF of NGC 3105 is deficient in objects with sub-solar masses when compared with the solar neighborhood. Low-mass objects in Haffner 17 and NGC 3105 are also more uniformly distributed on the sky than brighter, more massive, MS stars. This is consistent with both clusters having experienced significant dynamical evolution. © 2014. The American Astronomical Society. All rights reserved.

Reducible polyamidoamine-magnetic iron oxide self-assembled nanoparticles for doxorubicin delivery - Chen, J.; Shi, M.; Liu, P.; Ko, A.; Zhong, W.; Liao, W.; Xing, M.M.Q. (Biomaterials, 2014)
We report a reducible copolymer self-assembled with superparamagnetic iron oxide nanoparticles (SPIONs) to deliver doxorubicin (DOX) for cancer therapy. The copolymer of reducible polyamidoamine (rPAA) with poly(ethylene glycol)(PEG)/dodecyl amine graft was synthesized by Michael addition. rPAA@SPIONs were formed by the alkyl grafts of reducible copolymers intercalated with the oleic acid layer capped on the surface of magnetite nanocrystals. The intercalating area formed a reservoir for hydrophobic anti-cancer drug (DOX), whilst the PEG moiety in the copolymers helped the nanoparticle well-dispersible in aqueous solution. We employed two-photon excited fluorescence (TPEF) and coherent anti-Stokes Raman (CARS) to investigate drug delivery in intra-cellular structures of live cells, and used Vivaview® technique to show real-time inhibition efficacy of nanoparticles in live cells. rPAA@SPIONs present efficiently drug loading with reducible responsibility invitro tests. Finally, rPAA@SPIONs were tested in mice with xenograft MDA-MB-231 breast tumor though i.v. injection and inhibited tumor growth efficiently. MRI was used to monitor nanoparticles aggregation in tumor site. Histology and Prussian blue on kidney, liver, and heart in mice indicated that DOX/rPAA@SPIONs showed no significant toxicity for mice organs after 24 days treatment. © 2013 Elsevier Ltd.
Keywords: Breast tumor; Coherent anti-Stokes Raman; Magnetic nano-particles; Michael additions; Self assembled nanoparticles; Superparamagnetic iron oxide nanoparticles; Theranostics; Two-photon excited fluorescence; Addition reactions; Copolymers; Drug delivery; Grafts; Mammals; Nanomagnetics; Nanoparticles; Polyethylene oxides; Self assembly; Tumors; Polyethylene glycols; copolymer; doxorubicin; magnetic nanoparticle; nanocrystal; polyamidoamine; superparamagnetic iron oxide; animal experiment; animal model; animal tissue; aqueous solution; article; breast tumor; cancer chemotherapy; cancer inhibition; cell strain MCF 7; chemical structure; confocal laser microscopy; drug cytotoxicity; drug delivery system; drug release; fluorescence; heart; histology; human; human cell; hydrophobicity; in vitro study; in vivo study; kidney; liver; mouse; nanotechnology; nonhuman; nuclear magnetic resonance imaging; nude mouse; photon; polymerization; priority journal; synthesis; thermogravimetry; tumor growth; two photon excited fluorescence; Mus

A decade of probing the depths of thick multi-year ice to measure its borehole strength - Johnston, M. E. (Cold Regions Science and Technology, 2014)
This paper offers the most comprehensive set of property measurements on multi-year ice to date, in the interest of addressing one of the most significant unknowns for Arctic engineering: multi-year ice strength. Borehole strength results are presented from 56 old ice floes in the gray literature and more than 600 tests conducted on 23 multi-year ice floes over the past decade, including the first-published results over the full thickness of a 12.7. m thick, cold multi-year hummock. The ice borehole strength is obtained by categorizing the pressure vs. time histories for each test into one of four main types of failure behavior. Vertical profiles of the temperature, salinity and borehole strength of multi-year floes in spring and summer demonstrate that the properties of multi-year ice are highly variable in space and time. The mean borehole strength and standard deviation of cold (- 13. °C) multi-year ice is 34.2 ± 9.1 MPa, although strengths as high as 49.2. MPa do occur, making multi-year ice nearly twice as strong as cold first-year ice. The mean borehole strength and standard deviation of warm multi-year ice is 19.6 ± 7.2. MPa (at - 5 °C) and 10.3 ± 5.3 MPa (at 0°C). Ice temperature is shown to be the single largest factor influencing borehole strength: strength increases with decreasing ice temperature, however complex factors such as the ice failure mode and ice consolidation also bear upon the relation. For example, strengths measured in thick, level multi-year ice can be substantially higher than hummocked multi-year ice sampled at the same temperature, time of year and latitude. Similarly, a thoroughly weathered multi-year ice hummock in late summer can have considerably higher strength than a less weathered multi-year hummock in early spring. The study shows that multi-year ice does not deteriorate in the same manner as first-year ice, strength equations based solely on brine volume are not appropriate for multi-year ice and warm multi-year ice should not be assumed deteriorated. The viability of estimating the ice borehole strength from known ice temperatures is explored by fitting linear regressions to strength-temperature data for the two most common failure processes: well-defined yield failures (Type 2) and poorly-defined yield failures (Type 3). The Type 2 failure equation reproduces the measured strength profiles more closely than the Type 3 failure equation, but results are not ideal. A similar comparison was made for the effective borehole strength, i.e. the strength averaged over all test depths in a particular borehole. For the 64 boreholes examined, the Type 2 failure equation produced an upper bound for the effective borehole strength, but only when ice temperatures had been documented over at least half of the total ice thickness. © 2013.

Functional analysis of SleC from Clostridium difficile: An essential lytic transglycosylase involved in spore germination - Gutelius, D.; Hokeness, K.; Logan, S.M.; Reid, C.W. (Microbiology (United Kingdom), 2014)
Clostridium difficile is the most common cause of enteric disease and presents a major burden on healthcare systems globally due in part to the observed rapid rise in antibiotic resistance. The ability of C. difficile to form endospores is a key feature in the organism's pathogenesis and transmission, and contributes greatly to its resilient nature. Endospores are highly resistant to disinfection, allowing them to persist on hospital surfaces. In order for the organism to cause disease, the spores must germinate and revert to a vegetative form. While spore germination in Bacillus spp. is well understood, very little is known about this process in Clostridia. Here we report the characterization of SleC (CD0551) from C. difficile 630. Bioinformatic analysis of SleC indicated a multi-domained protein possessing a peptidoglycan-binding (PGB) domain, a SpoIID/LytB domain and an undefined N-terminal region. We have confirmed that SleC is an exo-acting lytic transglycosylase with the catalytic activity localized to the N-terminal region. Additionally, we have shown that both the N-terminal catalytic domain and the C-terminal PGB domain require muramyl-δ-lactam for substrate binding. As with carbohydrate-binding modules from cellulases and xylanases, the PGB domain may be responsible for increasing the processivity of SleC by concentrating the enzyme at the surface of the substrate. © 2014 SGM.
Keywords: bacterial protein; cellulase; glycosyltransferase; peptidoglycan; slec protein; unclassified drug; xylan endo 1,3 beta xylosidase; article; bioinformatics; catalysis; Clostridium; Clostridium difficile; controlled study; enzyme active site; enzyme activity; enzyme analysis; enzyme binding; nonhuman; priority journal; protein binding; spore germination

Regulatory ecotoxicity testing of engineered nanoparticles: Are the results relevant to the natural environment? - Park, S.; Woodhall, J.; Ma, G.; Veinot, J.G.C.; Cresser, M.S.; Boxall, A.B.A. (Nanotoxicology, 2014)
Engineered nanoparticles (ENPs) will be released to the environment during use or following the disposal of ENP-containing products and concerns have been raised over the risks of ENPs to the environment. Many studies have explored the toxicity of ENPs to aquatic organisms but these studies have usually been performed with little understanding of the ENPs' behaviour in the test media and the relationship between behaviour in the media to behaviour in natural waters. This study evaluated and compared the aggregation behaviour of four model gold nanoparticle (NP) types (coated with neutral, negative, positive and amphoteric cappings) in standard ecotoxicity test media and natural waters. The effects of humic acid (HA) and test organisms on aggregation were also investigated. In standard media, positive and neutral NPs were stable, whereas amphoteric and negative NPs generally showed substantial aggregation. In natural waters, amphoteric NPs were generally found to be stable, neutral and positive NPs showed substantial aggregation while negative NPs were stable in some waters and unstable in others. HA addition stabilised the amphoteric NPs, destabilised the positive NPs and had no effect on stability of negative NPs. The presence of invertebrates generally lowered the degree of particle aggregation while macrophytes had no effect. Given the dramatically different behaviours of ENPs in various standard media and natural waters, current regulatory testing may either under- or overestimate the toxicity of nanomaterials to aquatic organisms. Therefore, there is a pressing need to employ ecotoxicity media which better represent the behaviour of ENPs in natural system. © 2014 Informa UK, Ltd.
Keywords: gold nanoparticle; humic acid; nanomaterial; nanoparticle; aquatic species; article; controlled study; ecotoxicity; macrophyte; nanoengineering; nonhuman; physical chemistry; priority journal

TDRM/TDLM Workshop at the AOAC INTERNATIONAL Annual Meeting 2013 - Emons, H.; Weitzel, J.; Budin, J.; Cappozzo, J.; Jaudzem, G.; Quilliam, M.; Rettinger, M.; Sen, S.; Tholen, D.; Zink, D. (Accreditation and Quality Assurance, 2014)

Wear resistant carbon fiber reinforced Stellite alloy composites - Khoddamzadeh, A.; Liu, R.; Liang, M.; Yang, Q. (Materials and Design, 2014)
Stellite alloys are a family of cobalt-based superalloys that are the main engineering materials used for severe corrosion, wear and high temperature environments. These alloys are strengthened by various carbides. However, the presence of carbides can cause many problems although they are main agents for wear resistance. This research attempts to develop a class of novel composite materials which substitute carbon of Stellite alloys with carbon fiber, aiming to minimize the disadvantageous effects of carbides in the alloys. Two types of carbon fiber, plain carbon fiber and nickel-coated carbon fiber, are employed in the composites. The new materials are fabricated using hot isostatic pressing (HIP) technique. The microstructures of these composites are analyzed to investigate if any carbides are induced due to incorporating carbon fibers. The tribological properties of these new composites are characterized on a pin-on-disk tribometer. The experimental results show that the developed composites exhibit better wear resistance than that of medium-carbon Stellite alloys and comparable wear resistance to that of high-carbon Stellite alloys. © 2013 Elsevier Ltd.
Keywords: Carbon fiber reinforced; Cobalt-based superalloy; High-temperature environment; Nickel-coated carbon fiber; Pin-on-disk tribometers; Stellite alloy; Stellite alloy composites; Tribological properties; Carbides; Carbon; Carbon fibers; Hot isostatic pressing; Superalloys; Wear resistance; Stellite

Carbon and oxygen in the spectrum of HR 8799c - Konopacky, Q. M.; Barman, T. S.; Macintosh, B. A.; Marois, C. (Exploring the Formation and Evolution of Planetary Systems, 2014)
The field of exoplanet spectroscopy has grown tremendously in the last decade. With the discovery of gas giant planets at wide separations from their host stars via direct imaging, it is now possible to obtain exoplanet spectra with unprecedented spectral resolution. We present a medium resolution spectrum of the directly imaged exoplanet HR 8799c. This K-band spectrum was obtained using the integral field spectrograph OSIRIS on the Keck II telescope. Our spectrum shows numerous, well-resolved molecular lines from water and carbon monoxide (CO). There is no clear evidence for methane absorption, in spite of a best fit temperature of ~1100 K. We find a best fit surface gravity log(g) ~ 4.0, consistent with the inferred young age for the system (~30 Myr), and a continuum morphology consistent with previously-inferred dust clouds. Using the water and CO lines, we are able to estimate the C/O ratio for this planet. We find a ratio slightly higher than stellar (~0.65), which provides hints about the planet's formation. Copyright © 2013, International Astronomical Union.

Organic solvent-free cloud point extraction-like methodology using aggregation of graphene oxide - Deng, D.; Jiang, X.; Yang, L.; Hou, X.; Zheng, C. (Analytical Chemistry, 2014)
Because of its unique properties and capability of formation of well-dispersed aqueous colloids in aqueous phase, graphene oxide can be used for the efficient preconcentration of heavy metal ions prior to their determination. The complete collection of graphene oxide colloids from water has generally been considered to be insurmountable. Here, graphene oxide aggregation triggered by introducing NaCl was used to develop a novel organic solvent-free cloud point extraction-like method for the determination of trace toxic metals. The graphene oxide sheets were uniformly dispersed in aqueous samples or standard solutions for a fast and efficient adsorption of Pb(II), Cd(II), Bi(III), and Sb(III) owing to its hydrophilic character and the electrostatic repulsion among the graphene oxide sheets, and its aggregation immediately occurred when the electrostatic repulsion was eliminated via adding NaCl to neutralize the excessive negative charges on the surface of graphene oxide sheets. The aggregates of graphene oxide and analytes ions were separated and treated with hydrochloric acid to form a slurry solution. The slurry solution was pumped to mix with KBH4 solution to generate hydrides, which were subsequently separated from the liquid phase and directed to an atomic fluorescence spectrometer or directly introduced to an inductively coupled plasma optical emission spectrometer for detection. On the basis of a 50 mL sample volume, the limits of detection of 0.01, 0.002, 0.01, and 0.006 ng mL-1 were obtained for Pb, Cd, Bi, and Sb, respectively, when using atomic fluorescence spectrometry, providing 35-, 8-, 36-, and 37-fold improvements over the conventional method. Detection limits of 0.6, 0.15, 0.1, and 1.0 ng mL-1 were obtained with the use of slurry sampling inductively coupled plasma optical emission spectrometry. The method was applied for analysis of two Certified Reference Materials and three water samples for these elements. © 2013 American Chemical Society.
Keywords: Atomic fluorescence spectrometers; Atomic fluorescence spectrometry; Certified reference materials; Conventional methods; Electrostatic repulsion; Inductively coupled plasma optical emission spectrometer; Inductively coupled plasma-optical emission spectrometry; Organic solvent-free; Agglomeration; Antimony; Bismuth; Colloids; Electrostatics; Extraction; Fluorescence spectroscopy; Inductively coupled plasma; Metal ions; Optical emission spectroscopy; Organic solvents; Spectrometers; Trace elements; Graphene

TLOCI: a fully loaded speckle killing machine - Marois, Christian; Correia, Carlos; Véran, Jean-Pierre; Currie, Thayne (Exploring the Formation and Evolution of Planetary Systems, 2014)
A new high-contrast imaging subtraction algorithm (TLOCI) is presented to maximize a planet signal-to-noise ratio. The technique uses an input spectrum and template PSFs to optimize the reference image coefficient determination to minimize the flux contamination via self-subtraction (thus maximizing its throughput wavelength per wavelength) of any planet that have a similar spectrum to the template spectrum in the image, while trying, at the same time, to maximize the speckle noise subtraction. The optimization is performed by a correlation matrix conditioning. Using laboratory Gemini Planet Imager data, the new algorithm is shown to be superior to the simple/double difference, polynomial fit and original LOCI algorithm. Copyright © 2013, International Astronomical Union.
Keywords: stars: imaging; instrumentation: adaptive optics; methods: data analysis; techniques: image processing; (stars:) planetary systems

More evidence for an oscillation superimposed on the Hubble flow - Bell, M.B.; Comeau, S.P. (Astrophysics and Space Science, 2014)
In a recent investigation evidence was presented for a low-level sinusoidal oscillation superimposed on top of the Hubble flow. This oscillation was in VCMB, in a sample of type Ia Supernovae sources with accurate distances, and it was found to have a wavelength close to 40 Mpc. It became easily visible after the removal of several previously identified discrete velocity components. Its amplitude like that of the Hubble velocity showed an increase with distance, as would be expected for a constant-amplitude space oscillation. Here we report that this oscillation is also present in distance clumping in these sources, with the same wavelength, but in phase quadrature. The discrete velocity components do not play a role in detecting the distance clumping wavelength. Assuming that time proceeds from high cosmological redshift to low, the blue-shifted velocity peaks, which represent the contraction stage of the velocity oscillation, then lead the density peaks. With the discrete velocity components removed we also find evidence for at least one other, weaker velocity oscillation. It is found to have a wavelength similar to one reported in density clumping by previous investigators. In those cases the source samples were much larger. © 2013 Springer Science+Business Media Dordrecht.

Experimental analysis of applicability of a picosecond laser for micro-polishing of micromilled Inconel 718 superalloy - Hafiz, Abdullah M. Khalid; Bordatchev, Evgueni V.; Tutunea-Fatan, Remus O. (International Journal of Advanced Manufacturing Technology, 2014)
An increasing number of recent technological advancement is linked to the widespread adoptions of ultra-short picosecond (ps) pulsed laser in various applications of material processing. The superior capability of this laser is associated with the precise control of laser-material interaction as an outcome of extremely short interaction times resulting in almost-negligible heat affected zones. In this context, the present study explores the applicability of a picosecond laser in laser micro-polishing (LμP) of Ni-based superalloy Inconel 718 (IN718). The specific research goals of the present study constitute determination of melting regime-a mandatory phase for LμP, establishing the concept of polishability of the spatial contents of the initial surface topography and experimental demonstration of the process capability of a ps laser for potential micro-polishing applications. The initial surface topography was prepared by micromilling operation with a step-over of 50 μm and scallop height of 2 μm. The LμP experiments were performed at five different levels of fluence associated with the melting regime by changing the focal offset, a parameter denoting the working distance between workpiece surface and focusing lens focal plane. The LμP performance was evaluated based on the line profiling average surface roughness (Ra) spectrum distributed at different spatial wavelength intervals along the laser path trajectory. Furthermore, additional statistical metrics such as material ratio and power spectral density functions were analyzed in order to establish the process parameters associated with best achievable surface finish. The applicability of ps LμP was demonstrated in two regimes-1D (line) and 2D (area) polishing. During 1D LμP, significant (∼52 %) improvement of the surface quality was achieved by reducing an Ra value from 0.50 μm before polishing to an Ra value of 0.24 μm across the laser path trajectory on initially ground surface. In addition, an initially micromilled area of 4.5 × 4.5 mm was LμPed resulting in the reduction of an areal topography surface roughness (Sa) value from 0.435 to 0.127 μm (70.8 % surface quality improvement). © 2013 Her Majesty the Queen in Right of Canada as represented by: Julian Czajkowski.
Keywords: Laser micro-polishing; Inconel 718; Picosecond laser; Melting regime; Focal offset; Laser fluence; Surface quality

The potential of dextran-based glycoconjugates for development of Helicobacter pylori vaccine - Altman, Eleonora; Chandan, Vandana; Harrison, Blair (Glycoconjugate Journal, 2014)
We have recently demonstrated that synthetic glycoconjugates based on delipidated lipopolysaccharide (LPS) of Helicobacter pylori and containing an α(1-6)-glucan chain induced broadly cross-reactive functional antibodies in immunized animals. To investigate the candidacy of α(1-6)-glucan as an alternative vaccine strategy we prepared glycoconjugates based on dextrans produced by lactic acid bacteria Leuconostoc mesenteroides B512F and consisting of linear α(1-6)-glucan chains with limited branching. Three dextrans with averaged molecular masses of 5,000 Da, 3,500 Da and 1,500 Da, respectively, were modified with a diamino group-containing linker and conjugated to a carrier protein, tetanus toxoid (TT) or diphtheria toxoid (DT), and their immunological properties investigated. The conjugates were immunogenic in both rabbits and mice and induced specific IgG responses against α(1-6)-glucan-expressing H. pylori LPS. Studies performed with post-immune sera of mice and rabbits immunized with dextran-based conjugates demonstrated cross-reactivity with LPS from typeable and non-typeable strains of H. pylori and selected mutants. The post-immune sera from rabbits that received the conjugates exhibited functional activity against α(1-6)-glucan-positive strains of H. pylori. These data provide evidence that dextran-based conjugates may offer a simplified approach to the development of carbohydrate-based vaccines against H. pylori. © 2013 Her Majesty the Queen in Right of Canada.

Potential of NMR spectroscopy in the characterization of nonconventional oils - Majid, Abdul; Pihillagawa, Indu (Journal of Fuels, 2014)
NMR spectroscopy was applied for the characterization of two biomass based pyrolysis oil samples. The samples were extracted in various solvents and the extracts were investigated by both 1H and 13C NMR spectroscopy. Subsequent evaluation of the integrated analytical data revealed chemical information regarding semiquantitative estimation of various functional groups. This information could not have been obtained readily from the individual spectroscopic techniques. Semiquantitative estimation of the various functional groups allowed a comparison of the extraction efficiency of these groups in various solvents. The method is based on the premise that although the number of individual molecular species in pyrolysis oil liquid is large, most of these species are composed of a limited number of functional groups. The methodology provided information on the concentration of chemical functionalities that are potentially useful for synthetic modifications and may help to guide the use of pyrolysis oil as a chemical feedstock. The approach described is expected to be generally applicable to complex mixture of hydrocarbon oils such as bio-oils, oil sands bitumen, and coal pyrolysis oils.

Photo-uncaging of ceramides promotes reoganizatoin of liquid-ordered domains in supported lipid bilayers - Ramirez, Daniel M. Carter; Pitre, Spencer P.; Kim, Young Ah; Bittman, Robert; Johnston, Linda J. (Langmuir, 2014)
6-Bromo-7-hydroxycoumarin (Bhc)-caged ceramide (Cer) analogs were incorporated into supported lipid bilayers containing a mixture of coexisting liquid-ordered (Lo) and liquid-disordered (Ld) phases. The release of N-palmitoyl and N-butanoyl-D-erythro-sphingosine (C16- and C4-Cer) by the photolysis of caged Cers using long-wavelength UV light was studied using a combination of atomic force microscopy and fluorescence microscopy. This approach demonstrated the ability to generate Cer with spatial and temporal control, providing an alternative method to the enzymatic generation of Cer. The generation of C16-Cer from Bhc-C16-Cer disrupted the Lo domains, with the incorporation of small fluid-phase regions and the disappearance of some smaller domains. Cer-rich gel-phase domains were not observed, in contrast to results reported by either direct Cer incorporation or enzymatic Cer generation. The photorelease of C4-Cer from Bhc-C4-Cer resulted in qualitatively similar changes in bilayer morphology, with the disappearance of some Lo domains and no evidence of Cer-rich gel domains but with a smaller height difference between the ordered and disordered phases.