Evaluation of dynamic deformations of slab-on-girder bridge under moving trucks with corrosion-damaged columns - Mohammed, Amina M.; Almansour, Husham H.; Martín-Pérez, Beatriz (Engineering Structures, 2014)
A simplified hybrid linear/nonlinear dynamic finite element analysis (SHDFEA) based on visual inspection is introduced as part of a proposed semi-quantitative assessment approach of aged bridge columns. The focus is on the evaluation of the dynamic characteristics and behaviour of slab-on-girder bridges under moving trucks when their columns are subjected to severe corrosion damage. The proposed SHDFEA uses nonlinear finite element analysis to evaluate the damaged columns stiffness, mass and damping throughout the step-by-step time history analysis. The efficiency, accuracy and stability of the proposed SHDFEA are verified through different case studies, where very high numerical stability and fast convergence are achieved. The results show that the nonlinear dynamic analysis presents the most general approach to evaluate the effects of any level of corrosion damage in the column for any case of loading, boundary conditions and any progressive change in the column properties. However, linear dynamic analysis is found to be the most economical alternative when the columns are overdesigned. It is found that with severe local corrosion damage in traditionally designed slab-on-girder bridges columns, their static behaviour mostly remains in the elastic range, and the traffic load magnitude remains below their ultimate static capacity. It is also found that the changes in the bridge dynamic performance parameters are marginal when over-designed columns have severe corrosion damage and their safety and stability are critical.
Keywords: Semi-quantitative assessment approach; Corrosion damage; Slab-on-girder bridge; Nonlinear dynamic analysis; Finite element method

Silicon photomultiplier-based Compton Telescope for Safety and Security (SCoTSS) - Sinclair, Laurel; Saull, Patrick; Hanna, David; Seywerd, Henry; MacLeod, Audrey; Boyle, Patrick (IEEE Transactions on Nuclear Science, 2014)
A Compton gamma imager has been developed for use in consequence management operations and in security investigations. The imager uses solid inorganic scintillator, known for robust performance in field survey conditions. The design was constrained in overall size by the requirement that it be person transportable and operable from a variety of platforms. In order to introduce minimal dead material in the path of the incoming and scattered gamma rays, custom silicon photomultipliers (SiPMs), with a thin glass substrate, were used to collect the scintillation light from the scatter layers. To move them out of the path of the gamma rays, preamplification electronics for the silicon photomultipliers were located a distance from the imager. This imager, the Silicon photomultiplier Compton Telescope for Safety and Security (SCoTSS) is able to provide a one-degree image resolution in a ±45° field of view for a 10 mCi point source 40 m distant, within about one minute, for gamma-ray energies ranging from 344 keV to 1274 keV. Here, we present a comprehensive performance study of the SCoTSS imager.
Keywords: Compton Camera; Compton imager; Compton telescope; Gamma cameras; Gamma imager; Silicon photomultiplier; SiPM

Alignment of the NRC watt balance: Considerations, uncertainties and techniques - Sanchez, C. A.; Wood, B. M. (Metrologia, 2014)
This paper presents a comprehensive analysis of the alignment uncertainties in the NRC watt balance. We show that, due to the use of a beam balance in both phases of the experiment, some of the alignment errors of the weighing phase are correlated with errors in the moving phase, which makes our watt balance insensitive to some forms of misalignment. These correlations become inexact in the presence of parasitic forces acting on the coil former. We present evidence of such forces and estimate their effect and contribution to the various uncertainty components. Finally we describe the techniques used to align the apparatus and we give an estimate of all relevant alignment uncertainty components. © 2014 BIPM & IOP Publishing Ltd.
Keywords: Alignment; Errors; Alignment error; Comprehensive analysis; kilogram; Plancks constant; Watt balance; Uncertainty analysis

A new chemical probe for phosphatidylinositol kinase activity - Sherratt, Allison R.; Nasheri ardakan, Neda; McKay, Craig S.; O'Hara, Shifawn; Hunt, Ashly; Ning, Zhibin; Figeys, Daniel; Goto, Nathalie K.; Pezacki, John Paul (ChemBioChem, 2014)
Phosphatidylinositol kinases (PIKs) are key enzymatic regulators of membrane phospholipids and membrane environments that control many aspects of cellular function, from signal transduction to secretion, through the Golgi apparatus. Here, we have developed a photoreactive "clickable" probe, PIK-BPyne, to report the activity of PIKs. We investigated the selectivity and efficiency of the probe to both inhibit and label PIKs, and we compared PIK-BPyne to a wortmannin activity-based probe also known to target PIKs. We found that PIK-BPyne can act as an effective in situ activity-based probe, and for the first time, report changes in PI4K-IIIβ activity induced by the hepatitis C virus. These results establish the utility of PIK-BPyne for activity-based protein profiling studies of PIK function in native biological systems. Active PIKs: Phosphatidylinositol kinases (PIKs) are key enzymatic regulators of membrane phospholipids and environments that control many aspects of cellular function, from signal transduction to secretion. We developed a photoreactive "clickable" probe, PIK-BPyne, to assess activity of PIKs in native biological systems and demonstrated its ability to monitor hepatitis C virus-induced changes in PIK-IIIβ activity.
Keywords: phosphatidylinositol 3 kinase; phosphatidylinositol 3 kinase 110alpha; phosphatidylinositol kinase; phosphatidylinositol kinase 2alpha; phosphatidylinositol kinase 3alpha; phosphatidylinositol kinase 3beta; unclassified drug; wortmannin; article; breast cancer cell line; cancer cell line; chemical labeling; competitive inhibition; controlled study; enzyme activity; enzyme inhibition; female; genotype; hepatitis C; Hepatitis C virus; human; human cell; liver cell carcinoma; liver disease; liver transplantation; molecular probe; nonhuman; photoactivation; photoreactivation; PIK BPyne; primed in situ labeling; priority journal; protein analysis; protein function; uterine cervix cancer; virus replication; Western blotting; Hepatitis C virus

A density functional theory study of the reconstruction of gold (111) surfaces - Torres, Edmanuel; Dilabio, Gino A. (The Journal of Physical Chemistry C, 2014)
We studied (p × √3) gold (111) surface reconstructions within the DFT/PW91 approximation. Our findings clearly show that the reconstruction is energetically favorable in unreconstructed surfaces equal to or larger than the unit cell of the final reconstructed surface. Reconstructions in surfaces smaller than ∼2.95 nm in the [11̄0] direction are not more stable than the unreconstructed surface, and this may explain why (p × √3) type reconstructions have not been observed in subnanometer gold particles. We found that reconstructions with (22 × √3) and (23 × √3) unit cells, usually reported in experiments, are isoenergetic.
Keywords: Gold; Density functional theory studies; Gold particles; Reconstructed surfaces; Sub nanometers; Type reconstruction; Unit cells; Repair

Structural and magnetic behavior of the cubic oxyfluoride SrFeO 2F studied by neutron diffraction - Thompson, Corey M.; Blakely, Colin K.; Flacau, Roxana; Greedan, John E.; Poltavets, Viktor V. (Journal of Solid State Chemistry, 2014)
The oxyfluoride SrFeO2F has been prepared via a low temperature route involving the infinite-layer SrFeO2 and XeF2. SrFeO2F crystallizes in the cubic space group Pm-3m with disordered oxygen and fluorine atoms on the anion site. Recent reports demonstrated that SrFeO2F is antiferromagnetic at room temperature and the zero field cooled and field cooled curves diverge at ~150 K and ~60 K, suggesting that the material has a spin glassy magnetic state at low temperatures. In this article, variable-temperature neutron diffraction (4-723 K) was performed to clarify the magnetic behavior observed in this material. Neutron powder diffraction measurements confirmed the antiferromagnetic (AFM) ordering of the system at room temperature. Below 710(1) K, the magnetic structure is a G-type AFM structure characterized by a propagation vector k=(12, 12, 12). The ordered moments on Fe3+ are 4.35(6)μB at 4 K and 4.04(5)μB at 290 K. Our results indicate that the cubic structure is retained all the way to base temperature (4 K) in contrast to PbFeO 2F. These results are compared with those of Pb and Ba analogs which exhibit very similar magnetic behavior. Furthermore, the observation of magnetic reflections at 4 K in the diffraction pattern shows the absence of the previously proposed spin glassy behavior at low temperatures. Previous proposals to explain the ZFC/FC divergences are examined.
Keywords: Crystallography; Lead; Neutron diffraction; Antiferromagnetic orders; Antiferromagnetics; Magnetic behavior; Magnetic reflections; Oxyfluorides; Propagation vector; Variable temperature; Zero-field-cooled; Antiferromagnetism

Electrochemical oxygen reduction reaction - Si, Fengzhan; Zhang, Yuwei; Yan, Liang; Zhu, Jianbing; Xiao, Meiling; Liu, Changpeng; Xing, Wei; Zhang, Jiujun (Rotating Electrode Methods and Oxygen Reduction Electrocatalysts, 2014)
In this chapter, the fundamentals of oxygen reduction reaction (ORR) including thermodynamics and electrode kinetics are presented. The ORR kinetics including reaction mechanisms catalyzed by different electrode materials and catalysts including Pt, Pt alloys, carbon materials, and nonnoble metal catalysts are discussed based on the literature in terms of both experiment and theoretical approaches. It is emphasized that these fundamentals of ORR are necessary in order to perform the meaningful characterization of catalytic ORR activity using both rotating disk electrode and rotating ring-disk electrode methods.

Recent advances in silicon waveguide devices using sub-wavelength gratings - Halir, Robert; Ortega-Moñux, Alejandro; Schmid, Jens H.; Alonso-Ramos, Carlos; Lapointe, Jean; Xu, Dan-Xia; Wangüemert-Pérez, J. Gonzalo; Molina-Fernández, Ínigo; Janz, Siegfried (IEEE Journal on Selected Topics in Quantum Electronics, 2014)
As most integrated optics platforms, silicon offers only a fixed set of material refractive indices for designing devices. The ability of sub-wavelength patterned structures to synthesize arbitrary equivalent index values between nSi ~ 3.5 and nair = 1 has thus enabled completely new design approaches that have led to silicon waveguide devices with breakthrough performance. This review covers the latest advances in sub-wavelength structured fiber-to-chip grating couplers and multimode interference couplers. We discuss, among others, single-etch grating couplers with high coupling efficiency -1.8 dB), and broad bandwidth (115 nm at 3 dB), as well as ultra-short, high performance multi-mode interference couplers. We furthermore introduce the concept of dispersion engineering with sub-wavelength structures, showing its potential to increase the bandwidth of waveguide devices, including multi-mode interference couplers covering a 450 nm wavelength span.
Keywords: Dispersion engineering; Fiber-to-chip grating couplers; Multimode interference couplers; Silicon photonics; Sub-wave length grating; Diffraction gratings; Fixed platforms; Integrated optics; Photonics; Refractive index; Silicon; Waveguide components; Wavelength; Dispersion (waves)

Dispersive methods - Gaertner, Arnold A.; Yoon, Howard W.; Germer, Thomas A. (Experimental methods in the physical sciences, 2014)
This chapter discusses dispersive means of obtaining spectral resolution in spectrophotometry. These methods are used to spatially disperse or separate the various wavelengths of optical electromagnetic radiation to enable analysis of material properties in wavelength bandwidths that are appropriate to the material, the material property, and the material application under consideration. The two predominant spectrometer types are based upon gratings or prisms to physically separate the different wavelengths of the radiation. We discuss characteristics of each spectrometer type that result in their particular advantages and disadvantages. Important characteristics include the spectral range, spectral bandpass, spectral resolution, system aperture, and system throughput. The effects of imperfections in ideal spectrometers, such as wavelength error, stray light, and polarization effects, will be considered. Issues important to the choice of radiation sources will be discussed. Some characteristics of radiation detectors, such as linearity and noise, will be discussed. The techniques that are used to identify the presence and effects of these spectrometer properties will be discussed, as well as methods that are used to mitigate and/or quantify their effect upon the validity and accuracy of our measured results.

NIR initiated and pH sensitive single-wall carbon nanotubes for doxorubicin intracellular delivery - Liu, Shuhan; Ko, Alex C.-T.; Li, Wenyan; Zhong, Wen; Xing, Malcolm (Journal of Materials Chemistry B, 2014)
In this work, we synthesized a pH sensitive poly(ethylene glycol)-doxorubicin (PEG-DOX) on single-wall carbon nanotubes (SWNTs). Using multimodal nonlinear optical imaging microscopy, we found that low power (1 mW cm-2) near-infrared radiation can initiate prodrug burst release from the carbon nanotubes in seconds. The successful SWNTs capping with PEG-DOX (denoted PEG-DOX@SWNT) was determined by transmission electron microscopy and FTIR results. The in vitro release of DOX from the PEG-DOX@SWNT was evaluated upon changes of pH values and NIR treating time. The cytotoxicity of the PEG-DOX@SWNT was also evaluated. This dual-sensitive delivery system based on SWNTs provides a facile approach to promote drug release and kill cancer cells.

Fabricating nanostructures on fused silica using femtosecond infrared pulses combined with sub-nanojoule ultraviolet pulses - Yu, Xiaoming; Chang, Zenghu; Corkum, P. B.; Lei, Shuting (Optics Letters, 2014)
Circular craters with diameters of 500 nm are fabricated on the surface of fused silica by femtosecond ultraviolet-infrared (UV-IR) pulse trains with 0.8 nJ UV pulse energy. UV damage thresholds at different IR energies and UV-IR delays are measured. Diameters and depths of the ablated craters can be modified by adding the IR pulse and varying the UV-IR delays. These results demonstrate the feasibility of nanomachining using short wavelength lasers with pulse energy far below normal damage thresholds.
Keywords: Femtoseconds; Infrared pulse; Ultraviolet pulse

Mutational approaches to improve the biophysical properties of human single-domain antibodies - Kim, Dae Young; Hussack, Greg; Kandalaft, Hiba; Tanha, Jamshid (Biochimica et Biophysica Acta - Proteins and Proteomics, 2014)
Monoclonal antibodies are a remarkably successful class of therapeutics used to treat a wide range of indications. There has been growing interest in smaller antibody fragments such as Fabs, scFvs and domain antibodies in recent years. In particular, the development of human VH and VL single-domain antibody therapeutics, as stand-alone affinity reagents or as "warheads" for larger molecules, are favored over other sources of antibodies due to their perceived lack of immunogenicity in humans. However, unlike camelid heavy-chain antibody variable domains (VHHs) which almost unanimously resist aggregation and are highly stable, human VHs and VLs are prone to aggregation and exhibit poor solubility. Approaches to reduce VH and VL aggregation and increase solubility are therefore very active areas of research within the antibody engineering community. Here we extensively chronicle the various mutational approaches that have been applied to human VHs and VLs to improve their biophysical properties such as expression yield, thermal stability, reversible unfolding and aggregation resistance. In addition, we describe stages of the VH and VL development process where these mutations could best be implemented. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody.
Keywords: Aggregation; Mutation; Single-domain antibody; Stability; VH; VL

Effect of water-assisted extrusion and solid-state polymerization on the microstructure of PET/Clay nanocomposites - Dini, Maryam; Mousavand, Tahereh; Carreau, Pierre J.; Kamal, Musa R.; Ton-That, Minh-Tan (Polymer Engineering and Science, 2014)
An melt-mixing process has been used to prepare Poly(ethylene terephthalate) (PET)/clay nanocomposites with high degree of clay delamination. In this method, steam was fed into a twin-screw extruder (TSE) to reduce the PET molecular weight and to facilitate their diffusion into the gallery spacing of organoclays. Subsequently, the molecular weight (MW) reduction of the PET matrix due to hydrolysis by water was compensated by solid-state polymerization (SSP). The effect of the thermodynamic compatibility of PET and organoclays on the exfoliated microstructure of the nanocomposites was also examined by using three different nanoclays. The dispersion of Cloisite 30B (C30B) in PET was found to be better than that of Nanomer I.28E (I28E) and Cloisite Na+. The effect of feeding rate and consequently residence time on the properties of PET nanocomposites was also investigated. The results reveal more delamination of organoclay platelets in PET-C30B nanocomposites processed at low feeding rate compared to those processed at high feeding rate. Enhanced mechanical and barrier properties were observed in PET nanocomposites after SSP compared to the nanocomposites prepared by conventional melt-mixing. POLYM. ENG. SCI., 54:1723-1736, 2014.
Keywords: Delamination; Microstructure; Molecular weight; Organoclay; Polymerization; Clay delamination; Cloisite 30b; Mechanical and barriers; Poly(ethylene terephthalate) (PET); Residence time; Solid state polymerization; Thermodynamic compatibility; Twin screw extruders; Nanocomposites

Oxygen glucose deprivation-induced astrocyte dysfunction provokes neuronal death through oxidative stress - Gouix, Elsa; Buisson, Alain; Nieoullon, André; Kerkerian-Le Goff, Lydia; Tauskela, Joseph S.; Blondeau, Nicholas; Had-Aissouni, Laurence (Pharmacological Research, 2014)
Understanding the role of astrocytes in stroke is assuming increasing prominence, not only as an important component on its own within the neurovascular unit, but also because astrocytes can influence neuronal outcome. Ischemia may induce astrogliosis and other phenotypic changes, but these remain poorly understood, in part due to limitations in reproducing these changes in vitro. Dibutyryl cyclic AMP-differentiated cultured astrocytes are more representative of the in vivo astroglial cell phenotype, and were much more susceptible than undifferentiated astrocytes to an ischemic-like stress, oxygen-glucose deprivation (OGD). OGD altered the expression/distribution and activity of glial glutamate transporters, impaired cellular glutamate uptake and decreased intracellular levels of glutathione preferentially in differentiated astrocytes. Resistance to OGD was conferred by inhibiting caspase-3 with DEVD-CHO and oxidative stress by the antioxidant N-acetylcysteine (NAC). The resistance of undifferentiated astrocytes to OGD may result from a transient but selective morphological transformation into Alzheimer type II astrocytes, an intermediary stage prior to transforming into reactive astrocytes. Co-culture of neurons with OGD-exposed astrocytes resulted in neurotoxicity, but at surprisingly lower levels with dying differentiated astrocytes. The antioxidant NAC or the 5-LOX inhibitor AA861 added upon co-culture delayed (day 1) but did not prevent neurotoxicity (day 3). Astrocytes undergoing apoptosis as a result of ischemia may represent a transient neuroprotective mechanism via ischemia-induced release of glutathione, but oxidative stress was responsible for neuronal demise when ischemia compromised astrocyte supportive functions.
Keywords: Astrocyte differentiation; Neuroprotection; Inflammation; ROS; Glutamate transporters, Ischemia

Non-noble Fe-NX electrocatalysts supported on the reduced graphene oxide for oxygen reduction reaction - Monteverde Videla, Alessandro H. A.; Ban, Shuai; Specchia, Stefania; Zhang, Lei; Zhang, Jiujun (Carbon, 2014)
In this paper, the reduced graphene oxide (rGO) is synthesized from graphite oxide (GO) via microwave exfoliation method, and used to support non-noble metal Fe-NX based electrocatalysts (Fe-NX/rGO) for the oxygen reduction reaction (ORR). Tripyridyl triazine (TPTZ) is used as a ligand for Fe-NX catalyst preparation. The obtained catalyst presents a high content of pyridinic (N1) and pyrrolic (N2) nitrogen types on the catalyst surface (40.0% and 52.3% atomic concentrations, respectively) with Fe atomic content of 0.7%. A catalyst loading of 0.5 mg cm- 2 with a ionomer-to-carbon (ITC) mass ratio of 0.2 deposited on the glassy carbon electrode allows the highest ORR activity with the specific current of -0.35 mA mg-1 at a cell voltage of 0.8 V (vs. RHE). The overall electron transfer number obtained is of 3.98. Stability tests in acidic solution for this catalyst are also performed.
Keywords: Electrolytic reduction; Glass membrane electrodes; Graphene; Atomic concentration; Catalyst preparation; Catalyst surfaces; Electron transfer; Glassy carbon electrodes; Oxygen reduction reaction; Reduced graphene oxides; Reduced graphene oxides (RGO); Electrocatalysts

Properties of starless and prestellar cores in Taurus revealed by Herschel* SPIRE/PACS imaging - Marsh, K. A.; Griffin, M. J.; Palmeirim, P.; André, P.; Kirk, J.; Stamatellos, D.; Ward-Thompson, D.; Roy, A.; Bontemps, S.; Di Francesco, J.; Elia, D.; Hill, T.; et al. (Monthly Notices of the Royal Astronomical Society, 2014)
The density and temperature structures of dense cores in the L1495 cloud of the Taurus starforming region are investigated using Herschel Spectral and Photometric Imaging Receiver and Photodetector Array Camera and Spectrometer images in the 70, 160, 250, 350 and 500 μm continuum bands. A sample consisting of 20 cores, selected using spectral and spatial criteria, is analysed using a new maximum likelihood technique, COREFIT, which takes full account of the instrumental point spread functions.We obtain central dust temperatures, T0, in the range 6-12K and find that, in the majority of cases, the radial density falloff at large radial distances is consistent with the asymptotic r-2 variation expected for Bonnor-Ebert spheres. Two of our cores exhibit a significantly steeper falloff, however, and since both appear to be gravitationally unstable, such behaviour may have implications for collapse models. We find a strong negative correlation between t0 and peak column density, as expected if the dust is heated predominantly by the interstellar radiation field. At the temperatures we estimate for the core centres, carbon-bearing molecules freeze out as ice mantles on dust grains, and this behaviour is supported here by the lack of correspondence between our estimated core locations and the previously published positions of H13CO+ peaks. On this basis, our observations suggest a sublimation-zone radius typically ~104 au. Comparison with previously published N2H+ data at 8400 au resolution, however, shows no evidence for N2H+ depletion at that resolution.
Keywords: methods: data analysis; high angular resolution; stars: formation; protostars; ISM: clouds; submillimetre: ISM

Performance of vacuum insulation panel constructed with fiber-powder composite as core material - Mukhopadhyaya, Phalguni; Van Reenen, David; Normandin, Nicole (ASTM Special Technical Publication, 2014)
Buildings consume about 40 % of the national energy requirement in a developed country, and the addition of thermal insulation in building envelope construction is considered as the most primary and effective way to reduce energy consumption in buildings. Recent upgrades of energy codes in Europe and North America have also recommended higher levels of insulation in building envelopes. All these factors have provided a fresh impetus for the search for high-performance thermal insulation. Among various nonconventional insulations being introduced in the construction industry, as the next-generation thermal insulation, vacuum insulation panel (VIP) appears to be one of the most promising insulation materials, with the highest thermal insulating capacity (up to 10 times more thermally efficient than conventional thermal insulation materials). Quite naturally, the application of VIP in building envelope construction offers many advantages such as increased energy efficiency of exterior building envelopes, thinner wall thickness, optimum space use, reduced material consumption, etc. However, the acceptance of VIP in the construction industry is critically dependent on the cost and long-term performance. The expensive core material (e.g., precipitated silica or fumed silica) is one of the main reasons for the higher cost of VIPs that offer a satisfactory long-term service life in building envelope applications. To overcome this cost barrier for the mass application of VIPs in the building industry, researchers at the National Research Council Canada - Construction Portfolio have developed a low-cost fiber-powder composite core material for the VIP. This paper briefly introduces the concept of fiber-powder composite and present performance assessment data from laboratory-scale trial VIPs (300 mm by 300 mm) constructed with fiber-powder composite core materials.
Keywords: Construction industry; Coremaking; Costs; Energy efficiency; Energy utilization; Fibers; Silica; Solar buildings; Core material; Nano-porous; Performance assessment; Reduce energy consumption; Reduced material consumption; Vacuum insulation panel; Thermal insulation

Broadband single-photon-level memory in a hollow-core photonic crystal fibre - Sprague, M. R.; Michelberger, P. S.; Champion, T. F. M.; England, D. G.; Nunn, J.; Jin, X. -M.; Kolthammer, W. S.; Abdolvand, A.; Russell, P. S. J.; Walmsley, I. A. (Nature Photonics, 2014)
Storing information encoded in light is critical for realizing optical buffers for all-optical signal processing and quantum memories for quantum information processing. These proposals require efficient interaction between atoms and a well-defined optical mode. Photonic crystal fibres can enhance light-matter interactions and have engendered a broad range of nonlinear effects; however, the storage of light has proven elusive. Here, we report the first demonstration of an optical memory in a hollow-core photonic crystal fibre. We store gigahertz-bandwidth light in the hyperfine coherence of caesium atoms at room temperature using a far-detuned Raman interaction. We demonstrate a signal-to-noise ratio of 2.6:1 at the single-photon level and a memory efficiency of 27 ± 1%. Our results demonstrate the potential of a room-temperature fibre-integrated optical memory for implementing local nodes of quantum information networks.
Keywords: Information services; Particle beams; Quantum optics; Signal processing; All-optical signal processing; Efficient interaction; Hollow-core photonic crystal fibre; Hyperfine coherences; Light-matter interactions; Of quantum-information; Quantum-information processing; Single-photon level; Photonic crystal fibers

Determination of boron isotope compositions of geological materials by laser ablation MC-ICP-MS using newly designed high sensitivity skimmer and sample cones - Lin, Lin; Hu, Zhaochu; Yang, Lu; Zhang, Wen; Liu, Yongsheng; Gao, Shan; Hu, Shenghong (Chemical Geology, 2014)
The effects of addition of nitrogen gas with use of three different combinations of sample and skimmer cones on the performance of LA-MC-ICP-MS for in situ B isotope ratio measurements were investigated in detail. Compared to the standard arrangement (H skimmer cone+standard sample cone), sensitivities of B isotopes were improved by a factor of 2.4 and 3.8 with use of X skimmer cone+standard sampler cone and the X skimmer cone+Jet sample cone, respectively. The best within-run precision (2s) of 11B/10B was approximately 50ppm for B4 reference material (B content=31,400μg/g) with use of X skimmer cone+Jet sample cone. It was found that different cone combinations had significant effects on the instrument mass bias, but had little effect on the precisions of B isotope ratios. Addition of nitrogen (2-4ml/min) in the central channel gas did not improve the sensitivity of B. However, significant wider ion axial distribution profile and more stable mass-bias for B isotope ratios were evident. Under selected optimum conditions, good agreements between the measured δ11B values and the reference values were obtained for the international reference minerals (B4, Dravite, Elbaite, IMMRB1 and Schorl), the NIST SRM 610-612 synthetic soda-lime glasses and the MPI-DING glasses (GOR-128-G, GOR-132-G, and StHs6/80). It was found that for low-B containing (11ppm and 31ppm) materials, the precisions (2s) of 11B/10B can be improved by a factor of 2-10 by using the newly designed X-skimmer cone and Jet sample cone, compared to that of using the standard cones. The international reference mineral Danburite (δ11B of -14.92±6.77 2SD, n=32) showed a significant non-uniformity of B isotope ratio distribution. Our first boron isotopic results from standards GSD-1G (δ11B: 11.92±1.03, n=30), GSE-1G (δ11B: 1.63±0.32, n=30), GP-4 (δ11B: -5.85±1.01, n=40) and DD-1 (δ11B: -13.21±0.56, n=35) showed these materials were fairly homogeneous in boron isotope ratios, making them as good candidates as reference materials. The proposed LA-MC-ICPMS method is suitable for the direct determination of B isotope ratio in a variety of geological materials.
Keywords: Boron isotopes; Laser ablation; MC-ICP-MS; Nitrogen; Signal enhancement; Reference material; Signal enhancement

Oxygen reduction reaction in 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide: Addition of water as a proton species - Yuan, Xiao-Z; Alzate, Vanesa; Xie, Zhong; Ivey, Douglas G.; Quaz, Wei (Journal of the Electrochemical Society, 2014)
In this work, the physical and electrochemical behavior in a room temperature ionic liquid (RTIL), 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (BMP-TFSI) has been investigated. Water was added to BMP-TFSI and the effect of added water on conductivity, electrochemical window (ECW) and oxygen reduction reaction (ORR) was explored. The results show that for water amounts up to 1.0 wt%, water addition to BMP-TFSI slightly increases the conductivity of BMP-TFSI due to "shear relaxation" in the water-ionic liquid mixture. As a result of an "impurity effect", an increase in water addition to BMP-TFSI brings about a reduction in the ECW for the mixture. The rotating ring-disk electrode (RRDE) technique has confirmed that the ORR process in as-received BMP-TFSI can be assigned to one-electron transfer: O2 + e- h- O2-*. The reversibility of the O2/O2-* redox couple is greatly reduced with the addition of water. The suppressed anodic peak is likely attributable to the fact that the superoxide readily reacts with water. In water added BMP-TFSI, the ORR peak occurs at a more positive potential with an increased current density. The improved ORR activity is attributed to a proton effect and the increase in electron transfer number of the ORR in water added BMP-TFSI.
Keywords: Bis(trifluoromethane sulfonyl)imide; Electrochemical behaviors; Electrochemical window; One-electron transfer; Oxygen reduction reaction; Positive potential; Room temperature ionic liquids; Rotating ring-disk electrode techniques; Electron transitions; Ionic liquids; Mixtures; Oxygen; Protons; Electrolytic reduction

Identification of mechanisms for attenuation of the FSC043 mutant of Francisella tularensis SCHU S4 - Lindgren, Marie; Tancred, Linda; Golovliov, Igor; Conlan, Wayne; Twine, Susan M.; Sjöstedt, Anders (Infection and Immunity, 2014)
Previously, we identified a spontaneous, essentially avirulent mutant, FSC043, of the highly virulent strain SCHU S4 of Francisella tularensis subsp. tularensis. We have now characterized the phenotype of the mutant and the mechanisms of its attenuation in more detail. Genetic and proteomic analyses revealed that the pdpE gene and most of the pdpC gene were very markedly downregulated and, as previously demonstrated, that the strain expressed partially deleted and fused fupA and fupB genes. FSC043 showed minimal intracellular replication and induced no cell cytotoxicity. The mutant showed delayed phagosomal escape; at 18 h, colocalization with LAMP-1 was 80%, indicating phagosomal localization, whereas the corresponding percentages for SCHU S4 and the ΔfupA mutant were <10%. However, a small subset of the FSC043-infected cells contained up to 100 bacteria with LAMP-1 colocalization of around 30%. The unusual intracellular phenotype was similar to that of the ΔpdpC and ΔpdpC ΔpdpE mutants. Complementation of FSC043 with the intact fupA and fupB genes did not affect the phenotype, whereas complementation with the pdpC and pdpE genes restored intracellular replication and led to marked virulence. Even higher virulence was observed after complementation with both double-gene constructs. After immunization with the FSC043 strain, moderate protection against respiratory challenge with the SCHU S4 strain was observed. In summary, FSC043 showed a highly unusual intracellular phenotype, and based on our findings, we hypothesize that the mutation in the pdpC gene makes an essential contribution to the phenotype.
Keywords: lysosome associated membrane protein 1; bacterial gene; bacterial growth; bacterial strain; bacterial virulence; bacterium mutant; cell division; cytotoxicity; deletion mutant; down regulation; Francisella tularensis; Francisella tularensis FSC043; Francisella tularensis SCHU S4; gene construct; gene expression; gene mutation; gene replication; genetic analysis; macrophage; microarray analysis; microbial attenuation; mouse; phagosome; phenotype; protein analysis; protein expression; protein localization; proteomics; Bacterial Proteins; Cell Line; Mice, Inbred C57BL; Tularemia

Early allopolyploid evolution in the post-neolithic Brassica napus oilseed genome - Chalhoub, B.; Denoeud, F.; Liu, S.; Parkin, I. A. P.; Tang, H.; Wang, X.; Chiquet, J.; Belcram, H.; Tong, C.; Samans, B.; Corréa, M.; Da Silva, C.; et al. (Science, 2014)
Oilseed rape (Brassica napus L.) was formed ∼7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72x genome multiplication since the origin of angiosperms and high gene content.We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.
Erratum published in Vol 345, no. 6202 September 2014 DOI: 10.1126/science.1260782
Keywords: article; chromosome duplication; cytology; genetics; molecular evolution; plant genome; plant seed; polyploidy; rapeseed; Brassica napus; Chromosome Duplication; Evolution, Molecular; Genome, Plant; Polyploidy; Seeds

Quantum control: May the electric force be with you - Stolow, Albert (Nature Chemistry, 2014)

Reply to discussion by Chen and Gao of "The impact of fire on seismic resistance of fibre reinforced polymer strengthened concrete structural systems" - Bénichou, Noureddine; Mostafaei, Hossein; Green, Mark F.; Hollingshead, Kevin (Canadian Journal of Civil Engineering, 2014)

Raman scattering in Si/SiGe nanostructures: Revealing chemical composition, strain, intermixing, and heat dissipation - Mala, S. A.; Tsybeskov, L.; Lockwood, D. J.; Wu, X.; Baribeau, J.-M. (Journal of Applied Physics, 2014)
We present a quantitative analysis of Raman scattering in various Si/Si1-xGex multilayered nanostructures with well-defined Ge composition (x) and layer thicknesses. Using Raman and transmission electron microscopy data, we discuss and model Si/SiGe intermixing and strain. By analyzing Stokes and anti-Stokes Raman signals, we calculate temperature and discuss heat dissipation in the samples under intense laser illumination.
Keywords: Germanium; Phonons; Raman spectra; Raman scattering; Thermal conductivity

Two-photon excited state dynamics of dark valence, rydberg, and superexcited states in 1,3-butadiene - Schalk, Oliver; Boguslavskiy, Andrey E.; Stolow, Albert (The Journal of Physical Chemistry Letters, 2014)
Two-photon absorption in systems with parity permits access to states that cannot be prepared by one-photon absorption. Here we present the first time-resolved photoelectron spectroscopy study using this technique, applied to 1,3-butadiene, in which we investigated the dynamics of its dark valence, Rydberg, and superexcited states. The dark valence state dynamics are accessed via the Rydberg manifold, excited by two photons of 400 nm. We find that the 'dark' 21Ag state populated in this manner has a much longer lifetime than when accesses via the 11Bu 'bright' valence state when populated by one photon of 200 nm. In addition, we compared the dynamics of the 3sπ- and 3dπ-Rydberg states. These Rydberg states relax to the valence manifold on a subpicosecond time scale, with the 3sπ-Rydberg state decay rate being larger due to a stronger valence-Rydberg mixing. Finally, we investigated superexcited valence states that fragment or autoionize within 200 fs, likely without involving Rydberg states.
Keywords: Autoionization; Conical intersection; One photon absorption; Subpicosecond time scale; Superexcited state; Time-resolved photoelectron spectroscopy; Two photon absorption; Butadiene; Decay (organic); Excited states; Mixing; Photoelectron spectroscopy; Photons; Rydberg states; Two photon processes; Dynamics

Computational intelligence for urban infrastructure condition assessment: water transmission and distribution systems - Liu, Zheng; Kleiner, Yehuda (IEEE Sensors Journal, 2014)
Water transmission and distribution systems are critical urban infrastructure. The aging of water mains can lead to increased breakage rate, decreased hydraulic capacity, and deterioration of water quality. Condition assessment of water mains encompasses building computational model of failures, discerning distress indicators from inspection, rating health condition, and forecasting future failures. In this process, computational intelligence helps to achieve high-level awareness of system condition and facilitates the decision making in water main renewal and rehabilitation using the combined information from field knowledge, historical records, inspection results, and sensory data. This paper reviews computational approaches to achieve condition assessment of water mains. Inspection and sensor technologies involved in the assessment process are also briefly discussed.
Keywords: Computational intelligence; water pipe; information fusion

Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel - Marshall, J. P.; Moro-Martín, A.; Eiroa, C.; Kennedy, G.; Mora, A.; Sibthorpe, B.; Lestrade, J. -F.; Maldonado, J.; Sanz-Forcada, J.; Wyatt, M. C.; Matthews, B.; Horner, J.; et al. (Astronomy and Astrophysics, 2014)
Context. Stars form surrounded by gas-and dust-rich protoplanetary discs. Generally, these discs dissipate over a few (3-10) Myr, leaving a faint tenuous debris disc composed of second-generation dust produced by the attrition of larger bodies formed in the protoplanetary disc. Giant planets detected in radial velocity and transit surveys of main-sequence stars also form within the protoplanetary disc, whilst super-Earths now detectable may form once the gas has dissipated. Our own solar system, with its eight planets and two debris belts, is a prime example of an end state of this process. Aims. The Herschel DEBRIS, DUNES, and GT programmes observed 37 exoplanet host stars within 25 pc at 70, 100, and 160 μm with the sensitivity to detect far-infrared excess emission at flux density levels only an order of magnitude greater than that of the solar system's Edgeworth-Kuiper belt. Here we present an analysis of that sample, using it to more accurately determine the (possible) level of dust emission from these exoplanet host stars and thereafter determine the links between the various components of these exoplanetary systems through statistical analysis. Methods. We have fitted the flux densities measured from recent Herschel observations with a simple two parameter (Td, L IR/L) black-body model (or to the 3σ upper limits at 100 μm). From this uniform approach we calculated the fractional luminosity, radial extent and dust temperature. We then plotted the calculated dust luminosity or upper limits against the stellar properties, e.g. effective temperature, metallicity, and age, and identified correlations between these parameters. Results. A total of eleven debris discs are identified around the 37 stars in the sample. An incidence of ten cool debris discs around the Sun-like exoplanet host stars (29 ± 9%) is consistent with the detection rate found by DUNES (20.2 ± 2.0%). For the debris disc systems, the dust temperatures range from 20 to 80 K, and fractional luminosities (L IR/L) between 2.4 ×10-6 and 4.1 ×10 -4. In the case of non-detections, we calculated typical 3σ upper limits to the dust fractional luminosities of a few ×10 -6. Conclusions. We recover the previously identified correlation between stellar metallicity and hot-Jupiter planets in our data set. We find a correlation between the increased presence of dust, lower planet masses, and lower stellar metallicities. This confirms the recently identified correlation between cold debris discs and low-mass planets in the context of planet formation by core accretion.
Keywords: Astrophysics; Debris; Dust; Extrasolar planets; Luminance; Solar system; Circumstellar matters; Dust temperatures; Effective temperature; Infrared: planetary systems; Infrared: star; Planet formation; Planet-disk interactions; Second generation; Stars

The black hole mass of NGC 4151. II. Stellar dynamical measurement from near-infrared integral field spectroscopy - Onken, Christopher A.; Valluri, Monica; Brown, Jonathan S.; McGregor, Peter J.; Peterson, Bradley M.; Bentz, Misty C.; Ferrarese, Laura; Pogge, Richard W.; Vestergaard, Marianne; Storchi-Bergmann, Thaisa; Riffel, Rogemar A. (The Astrophysical Journal, 2014)
We present a revised measurement of the mass of the central black hole (M BH) in the Seyfert 1 galaxy NGC 4151. The new stellar dynamical mass measurement is derived by applying an axisymmetric orbit-superposition code to near-infrared integral field data obtained using adaptive optics with the Gemini Near-infrared Integral Field Spectrograph (NIFS). When our models attempt to fit both the NIFS kinematics and additional low spatial resolution kinematics, our results depend sensitively on how χ2 is computed - probably a consequence of complex bar kinematics that manifest immediately outside the nuclear region. The most robust results are obtained when only the high spatial resolution kinematic constraints in the nuclear region are included in the fit. Our best estimates for the black hole mass and H-band mass-to-light ratio are M BH ∼ 3.76 ± 1.15 × 107 M ⊙ (1σ error) and Υ⊙ H ∼ 0.34 ± 0.03 M ⊙/L ⊙ (3σ error), respectively (the quoted errors reflect the model uncertainties). Our black hole mass measurement is consistent with estimates from both reverberation mapping () and gas kinematics (; 1σ errors), and our best-fit mass-to-light ratio is consistent with the photometric estimate of Υ⊙ H = 0.4 ± 0.2 M ⊙/L ⊙. The NIFS kinematics give a central bulge velocity dispersion σc = 116 ± 3 km s-1, bringing this object slightly closer to the M BH-σ relation for quiescent galaxies. Although NGC 4151 is one of only a few Seyfert 1 galaxies in which it is possible to obtain a direct dynamical black hole mass measurement - and thus, an independent calibration of the reverberation mapping mass scale - the complex bar kinematics makes it less than ideally suited for this purpose.
Keywords: galaxies: active; galaxies: individual (NGC 4151); galaxies: kinematics and dynamics; galaxies: nuclei; galaxies: Seyfert; methods: numerical

Priming and testing silicon patch-clamp neurochips - Py, Christophe; Denhoff, Michael W.; Sabourin, Nicaulas; Weber, John; Shiu, Matthew; Zhao, Ping (New Biotechnology, 2014)
We report on the systematic and automated priming and testing of silicon planar patch-clamp chips after their assembly in Plexiglas packages and sterilization in an air plasma reactor. We find that almost 90% of the chips are successfully primed by our automated setup, and have a shunt capacitance of between 10. pF and 30. pF. Blocked chips are mostly due to glue invasion in the well, and variability in the manual assembly process is responsible for the distribution in shunt capacitance value. Priming and testing time with our automated setup is less than 5. min per chip, which is compatible with the production of large series for use in electrophysiology experiments.
Keywords: Capacitance; Plasma applications; Silicon; Air plasmas; Automated setup; Manual assembly; Neuro-chips; Patch-clamp; Planar patch clamps; Shunt capacitance; Testing time; Electrophysiology; glue; poly(methyl methacrylate); silicon; accuracy; air plasma reactor; article; automation; biochip; biocompatibility; bioreactor; controlled study; electric potential; electrophysiology; instrument sterilization; materials testing; nanofabrication; neurochip; planar patch clamp; priority journal

Special issue on joining technologies for composites - Backman, D. (Journal of Strain Analysis for Engineering Design, 2014)

Elemental abundance analyses with DAO spectrograms. XXXIV. A three-dimensional graphical examination of the elemental abundances of the mercury-manganese and metallic-line stars - Yüce, Kutluay; Adelman, Saul J. (Publications of the Astronomical Society of the Pacific, 2014)
Detailed analyses of high-dispersion, high signal-to-noise spectra enable astronomers to infer many stellar properties. We study nonmagnetic normal and chemically peculiar B, A, and F stars to understand the details of their optical region abundances via graphical techniques using two kinds of figures for 32 elements. By characterizing the anomalies of the mercury-manganese (HgMn) and the metallic-line (Am) stars, we provide major theoretical tests. We confirmed the known Hg dichotomy between HgMn stars, which are greatly overabundant, and the Am stars with normal abundances. Further P, Ga, Xe, Pt, and Au values were only overabundant for some HgMn stars, and lines of the rare earth elements, such as Sm and Eu, were seen only in some Am and normal stars. These observations might be due in some cases to changes in the major ionization state of atoms in the relevant stellar atmosphere. That some HgMn stars with large Ga overabundances have positions close in the H-R diagram to HgMn stars that lack Ga II lines in the optical region suggests a dichotomy similar to Hg with a boundary close to, but not identical, to that for Hg. The spread of the abundance anomalies for a given element tends to be smaller among the Am stars than among the HgMn stars. Star-to-star differences are superimposed upon abundance trends.

Optimizing cone beam CT scatter estimation in egs-cbct for a clinical and virtual chest phantom - Thing, Rune Slot; Mainegra-Hing, Ernesto (Medical Physics, 2014)
Purpose: Cone beam computed tomography (CBCT) image quality suffers from contamination from scattered photons in the projection images. Monte Carlo simulations are a powerful tool to investigate the properties of scattered photons.egs-cbct, a recent EGSnrc user code, provides the ability of performing fast scatter calculations in CBCT projection images. This paper investigates how optimization of user inputs can provide the most efficient scatter calculations. Methods: Two simulation geometries with two different x-ray sources were simulated, while the user input parameters for the efficiency improving techniques (EITs) implemented inegs-cbct were varied. Simulation efficiencies were compared to analog simulations performed without using any EITs. Resulting scatter distributions were confirmed unbiased against the analog simulations. Results: The optimal EIT parameter selection depends on the simulation geometry and x-ray source. Forced detection improved the scatter calculation efficiency by 80%. Delta transport improved calculation efficiency by a further 34%, while particle splitting combined with Russian roulette improved the efficiency by a factor of 45 or more. Combining these variance reduction techniques with a built-in denoising algorithm, efficiency improvements of 4 orders of magnitude were achieved. Conclusions: Using the built-in EITs inegs-cbct can improve scatter calculation efficiencies by more than 4 orders of magnitude. To achieve this, the user must optimize the input parameters to the specific simulation geometry. Realizing the full potential of the denoising algorithm requires keeping the statistical uncertainty below a threshold value above which the efficiency drops exponentially.
Keywords: algorithm; analytical parameters; computed tomography scanner; computer simulation; cone beam computed tomography; controlled study; geometry; imaging phantom; intermethod comparison; light scattering; noise reduction; process optimization; thorax; X ray

The Aβ peptides-activated calcium-sensing receptor stimulates the production and secretion of vascular endothelial growth factor-A by normoxic adult human cortical astrocytes - Dal Prà, Ilaria; Armato, Ubaldo; Chioffi, Franco; Pacchiana, Raffaella; Whitfield, James F.; Chakravarthy, Balu; Gui, Li; Chiarini, Anna (NeuroMolecular Medicine, 2014)
The excess vascular endothelial growth factor (VEGF) produced in the Alzheimer's disease (AD) brain can harm neurons, blood vessels, and other components of the neurovascular units (NVUs). But could astrocytes partaking in networks of astrocyte-neuron teams and connected to blood vessels of NVUs contribute to VEGF production? We have shown with cultured cerebral cortical normal (i.e., untransformed) adult human astrocytes (NAHAs) that exogenous amyloid-β peptides (Aβs) stimulate the astrocytes to make and secrete large amounts of Aβs and nitric oxide by a mechanism mediated through the calcium-sensing receptor (CaSR). Here, we report that exogenous Aβs stimulate the NAHAs to produce and secrete even VEGF-A through a CaSR-mediated mechanism. This is indicated by the ability of Aβs to specifically bind the CaSR, and the capability of a CaSR activator, the "calcimimetic" NPS R-568, to imitate, and of the CaSR antagonist, "calcilytic" NPS 2143, to inhibit, the Aβs stimulation of VEGF-A production and secretion by the NAHAs. Thus, Aβs that accumulate in the AD brain may make the astrocytes that envelop and functionally collaborate with neurons into multi-agent AD-driving "machines" via a CaSR signaling mechanism(s). These observations suggest the possibility that CaSR allosteric antagonists such as NPS 2143 might impede AD progression.
Keywords: Amyloid-β; Human adult; Astrocyte; Calcimimetic; Calcilytic; Calcium-sensing receptor; Vascular endothelial growth factor-A

An improved sampling approach to overcome transient effect in staircase waveform - Zuliang, Lu; Yan, Yang; Lu, Huang; Lei, Wang; So, Eddy (2014 Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014)
The advantage of the new sampling approach to overcome transient effect in staircase waveform is described. Based on this sampling approach, a general form is developed in this paper. In this form, more samples of the staircase waveform are used for calculations in the measurement. It provides a better basis to achieve a lower uncertainty. The necessary theoretical basis is analyzed with interesting characteristics. The experiment results are reported.
Keywords: Sampling; Digital-analog conversion; Transient effect; Wave forms; Discrete Fourier transforms

TADPOL : a 1.3 mm survey of dust polarization in star-forming cores and regions - Hull, Charles L. H.; Plambeck, Richard L.; Kwon, Woojin; Bower, Geoffrey C.; Carpenter, John M.; Crutcher, Richard M.; Fiege, Jason D.; Franzmann, Erica; Hakobian, Nicholas S.; Heiles, Carl; Houde, Martin; Hughes, A. Meredith; et al. (Astrophysical Journal, Supplement Series, 2014)
We present λ 1.3 mm Combined Array for Research in Millimeter-wave Astronomy observations of dust polarization toward 30 star-forming cores and eight star-forming regions from the TADPOL survey. We show maps of all sources, and compare the 2.″5 resolution TADPOL maps with 20″ resolution polarization maps from single-dish submillimeter telescopes. Here we do not attempt to interpret the detailed B-field morphology of each object. Rather, we use average B-field orientations to derive conclusions in a statistical sense from the ensemble of sources, bearing in mind that these average orientations can be quite uncertain. We discuss three main findings. (1) A subset of the sources have consistent magnetic field (B-field) orientations between large (20″) and small (2.″5) scales. Those same sources also tend to have higher fractional polarizations than the sources with inconsistent large-to-small-scale fields. We interpret this to mean that in at least some cases B-fields play a role in regulating the infall of material all the way down to the 1000 AU scales of protostellar envelopes. (2) Outflows appear to be randomly aligned with B-fields; although, in sources with low polarization fractions there is a hint that outflows are preferentially perpendicular to small-scale B-fields, which suggests that in these sources the fields have been wrapped up by envelope rotation. (3) Finally, even at 2.″5 resolution we see the so-called polarization hole effect, where the fractional polarization drops significantly near the total intensity peak. All data are publicly available in the electronic edition of this article.
Keywords: ISM: magnetic fields; magnetic fields; polarization; stars: formation; stars: magnetic field; stars: protostars

Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy photon beams - McEwen, Malcolm; DeWerd, Larry; Ibbott, Geoffrey; Followill, David; Rogers, David W.O.; Seltzer, Stephen; Seuntjens, Jan (Medical Physics, 2014)
An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accuracy and consistency of the protocol's implementation. The components of the uncertainty budget in determining absorbed dose to water at the reference point are introduced and the magnitude of each component discussed. Finally, the consistency of experimental determination of N D,w coefficients is discussed. It is expected that the implementation of this addendum will be straightforward, assuming that the user is already familiar with TG-51. The changes introduced by this report are generally minor, although new recommendations could result in procedural changes for individual users. It is expected that the effort on the medical physicist's part to implement this addendum will not be significant and could be done as part of the annual linac calibration.
Keywords: rotraxate; water; accuracy; air temperature; atmospheric pressure; calibration; dosimetry; humidity; ionization chamber; linear accelerator; megavoltage radiotherapy; Monte Carlo method; photon therapy; practice guideline; radiation beam; radiation dose distribution; radiation field; water temperature

Catalog of observed tangents to the spiral arms in the milky way galaxy - Vallée, Jacques P. (Astrophysical Journal, Supplement Series, 2014)
From the Sun's location in the Galactic disk, one can use different arm tracers (CO, H I, thermal or ionized or relativistic electrons, masers, cold and hot dust, etc.) to locate a tangent to each spiral arm in the disk of the Milky Way. We present a master catalog of the astronomically observed tangents to the Galaxy's spiral arms, using different arm tracers from the literature. Some arm tracers can have slightly divergent results from several papers, so a mean value is taken - see the Appendix for CO, H II, and masers. The catalog of means currently consists of 63 mean tracer entries, spread over many arms (Carina, Crux-Centaurus, Norma, Perseus origin, near 3 kpc, Scutum, Sagittarius), stemming from 107 original arm tracer entries. Additionally, we updated and revised a previous statistical analysis of the angular offset and linear separation from the mid-arm for each different mean arm tracer. Given enough arm tracers, and summing and averaging over all four spiral arms, one could determine if arm tracers have separate and parallel lanes in the Milky Way. This statistical analysis allows a cross-cut of a Galactic spiral arm to be made, confirming a recent discovery of a linear separation between arm tracers. Here, from the mid-arm's CO to the inner edge's hot dust, the arm halfwidth is about 340 pc; doubling would yield a full arm width of 680 pc. We briefly compare these observations with the predictions of many spiral arm theories, notably the density wave theory.
Keywords: catalogs; Galaxy: disk; Galaxy: fundamental parameters; Galaxy: structure; ISM: kinematics and dynamics

Copper fixed-point measurements for radiation thermometry at National Research Council - Todd, A. D .W.; Woods, D. J. (International Journal of Thermophysics, 2014)
Due to its high transition temperature relative to other fixed points defined in the International Temperature Scale of 1990 (ITS-90) and its relatively low cost compared to silver and gold, copper is often chosen as the fixed point used to define the ITS-90 above 1235 K at national measurement institutes. Measurement of the copper freezing point can be done in a variety of furnaces. Although there are a large number of copper fixed-point designs, we expect the freezing temperatures to be the same. The difference between realizing different sized fixed points and the use of different furnaces in which to realize them is explored here. A traditional, large aperture fixed-point containing over 600 g of copper is compared to a hybrid-type fixed point containing only 15 g of copper and a commercial fixed point. Three types of furnaces including a heat-pipe furnace, a compact furnace, and a high-temperature blackbody were used to realize the copper freezing point. Between the fixed-point types, only the length of the plateau differed. However, a significant difference was found between the freezing temperatures determined in the different furnaces, and this difference was independent of cell type.
Keywords: Copper fixed-points; Heat pipe; Hybrid fixed points; Radiation thermometry

A mussel (Mytilus edulis) tissue certified reference material for the marine biotoxins azaspiracids - McCarron, Pearse; Giddings, Sabrina D.; Reeves, Kelly L.; Hess, Phillip; Quilliam, Michael A. (Analytical and Bioanalytical Chemistry, 2014)
Azaspiracids (AZAs) are lipophilic biotoxins produced by marine algae that can contaminate shellfish and cause human illness. The European Union (EU) regulates the level of AZAs in shellfish destined for the commercial market, with liquid chromatography-mass spectrometry (LC-MS) being used as the official reference method for regulatory analysis. Certified reference materials (CRMs) are essential tools for the development, validation, and quality control of LC-MS methods. This paper describes the work that went into the planning, preparation, characterization, and certification of CRM-AZA-Mus, a tissue matrix CRM, which was prepared as a wet homogenate from mussels (Mytilus edulis) naturally contaminated with AZAs. The homogeneity and stability of CRM-AZA-Mus were evaluated, and the CRM was found to be fit for purpose. Extraction and LC-MS/MS methods were developed to accurately certify the concentrations of AZA1 (1.16 mg/kg), AZA2 (0.27 mg/kg), and AZA3 (0.21 mg/kg) in the CRM. Quantitation methods based on standard addition and matrix-matched calibration were used to compensate for the matrix effects in LC-MS/MS. Other toxins present in this CRM at lower levels were also measured with information values reported for okadaic acid, dinophysistoxin-2, yessotoxin, and several spirolides.]
Keywords: Azaspiracids; Matrix certified reference material; Seafood safety; Matrix effects; Liquid chromatography; mass spectrometry

Biologically active polymers from spontaneous carotenoid oxidation : a new frontier in carotenoid activity - Johnston, James B.; Nickerson, James G.; Daroszewski, Janusz; Mogg, Trevor J.; Burton, Graham W. (PLoS ONE, 2014)
In animals carotenoids show biological activity unrelated to vitamin A that has been considered to arise directly from the behavior of the parent compound, particularly as an antioxidant. However, the very property that confers antioxidant activity on some carotenoids in plants also confers susceptibility to oxidative transformation. As an alternative, it has been suggested that carotenoid oxidative breakdown or metabolic products could be the actual agents of activity in animals. However, an important and neglected aspect of the behavior of the highly unsaturated carotenoids is their potential to undergo addition of oxygen to form copolymers. Recently we reported that spontaneous oxidation of ß-carotene transforms it into a product dominated by ß-carotene-oxygen copolymers. We now report that the polymeric product is biologically active. Results suggest an overall ability to prime innate immune function to more rapidly respond to subsequent microbial challenges. An underlying structural resemblance to sporopollenin, found in the outer shell of spores and pollen, may allow the polymer to modulate innate immune responses through interactions with the pattern recognition receptor system. Oxygen copolymer formation appears common to all carotenoids, is anticipated to be widespread, and the products may contribute to the health benefits of carotenoid-rich fruits and vegetables.

Measurements of wood pellets self-heating kinetic parameters using isothermal calorimetry - Guo, Wendi; Trischuk, Ken; Bi, Xiaotao; Lim, C. Jim; Sokhansanj, Shahab (Biomass and Bioenergy, 2014)
Wood pellets release heat and gases during storage. A TAM air isothermal calorimeter was used to measure the rate of heat release by bulk pellets at temperatures ranging from 30 to 50°C. The results showed that self-heating rate at the tested temperature range strongly depended on the reaction temperature and the age of pellets. Heat release rate increased as the reaction temperature increased but the rate was not sensitive to pellets moisture content. The activation energy of the self-heating reaction increased with the age of pellets. A simple global kinetic model for self-heating was developed from the experimental data. The model can be applied to simulate the self-heating process in pellets storage containers at different storage temperatures and age of stored pellets.
Keywords: Activation energy; Calorimeters; Digital storage; Heating; Isotherms; Kinetic parameters; Kinetic theory; Spontaneous combustion; Global kinetic modeling; Heat Release Rate (HRR); Heat release rate measurement; Isothermal calorimeter; Isothermal calorimetry; Kinetic modeling; Storage temperatures; Wood pellet; Pelletizing; activation energy; bioenergy; biomass power; biotechnology; calorimetry; combustion; heat flux; isotherm; numerical model; reaction kinetics; storage; wood

Discovery of new magnetic early-B stars within the MiMeS HARPSpol survey - Alecian, E.; Kochukhov, O.; Petit, V.; Grunhut, J.; Landstreet, J.; Oksala, M. E.; Wade, G. A.; Hussain, G.; Neiner, C.; Bohlender, D. (Astronomy and Astrophysics, 2014)
Context. The Magnetism in Massive Stars (MiMeS) project aims at understanding the origin of the magnetic fields in massive stars as well as their impact on stellar internal structure, evolution, and circumstellar environment. Aims. One of the objectives of the MiMeS project is to provide stringent observational constraints on the magnetic fields of massive stars; however, identification of magnetic massive stars is challenging, as only a few percent of high-mass stars host strong fields detectable with the current instrumentation. Hence, one of the first objectives of the MiMeS project was to search for magnetic objects among a large sample of massive stars, and to build a sub-sample for in-depth follow-up studies required to test the models and theories of fossil field origins, magnetic wind confinement and magnetospheric properties, and magnetic star evolution. Methods. We obtained high-resolution spectropolarimetric observations of a large number of OB stars thanks to three large programs (LP) of observations that have been allocated on the high-resolution spectropolarimeters ESPaDOnS, Narval, and the polarimetric module HARPSpol of the HARPS spectrograph. We report here on the methods and first analysis of the HARPSpol magnetic detections. We identified the magnetic stars using a multi-line analysis technique. Then, when possible, we monitored the new discoveries to derive their rotation periods, which are critical for follow-up and magnetic mapping studies. We also performed a first-look analysis of their spectra and identified obvious spectral anomalies (e.g., surface abundance peculiarities, Hα emission), which are also of interest for future studies. Results. In this paper, we focus on eight of the 11 stars in which we discovered or confirmed a magnetic field from the HARPSpol LP sample (the remaining three were published in a previous paper). Seven of the fields were detected in early-type Bp stars, while the last field was detected in the Ap companion of a normal early B-type star. We report obvious spectral and multiplicity properties, as well as our measurements of their longitudinal field strengths, and their rotation periods when we are able to derive them. We also discuss the presence or absence of Hα emission with respect to the theory of centrifugally-supported magnetospheres.
Keywords: Magnetic fields; Magnetosphere; Analysis techniques; Internal structure; Longitudinal fields; Spectral anomalies; Spectropolarimeters; Stars: chemically peculiar; Stars: magnetic field; Stars: massive; Stars

Calcium metaborate as a cathode additive to improve the high-temperature properties of nickel hydroxide electrodes for nickel-metal hydride batteries - Li, Jing; Shangguan, Enbo; Guo, Dan; Li, Quanmin; Chang, Zhaorong; Yuan, Xiao-Zi; Wang, Haijiang (Journal of Power Sources, 2014)
In this paper, a novel additive, calcium metaborate (CMB), is proposed to improve the high-temperature characteristics of the nickel electrodes for nickel-metal hydride batteries. As a soluble calcium salt, CMB can easily and uniformly be dispersed in the nickel electrodes. The effects of CMB on the nickel electrode are investigated via a combination of cyclability, capacity retention, electrochemical impedance spectroscopy, scanning electron microscope and X-ray diffraction. Compared with conventional nickel electrodes, the electrode containing 0.5 wt.% CMB exhibits superior electrode properties including enhanced discharge capacity, improved high-rate discharge ability and excellent cycle stability at an elevated temperature (70 °C). The improved cell performance of the nickel electrode containing CMB additives can be attributable to the increased oxygen evolution overvoltage and slower oxygen evolution rate. Compared with insoluble calcium salts, such as Ca(OH) 2, CaCO3, and CaF2, CMB is more effective as a cathode additive to improve the high-temperature performance of Ni-MH batteries.
Keywords: Nickelemetal hydride battery; High-temperature performance; Soluble calcium salt; Calcium metaborate; Cycle stability

Differences in soil solution chemistry between soils amended with nanosized CuO or Cu reference materials : implications for nanotoxicity tests - McShane, Heather V. A.; Sunahara, Geoffrey I.; Whalen, Joann K.; Hendershot, William H. (Environmental Science and Technology, 2014)
Soil toxicity tests for metal oxide nanoparticles often include micrometer-sized oxide and metal salt treatments to distinguish between toxicity from nanometer-sized particles, non-nanometer-sized particles, and dissolved ions. Test result will be confounded if each chemical form has different effects on soil solution chemistry. We report on changes in soil solution chemistry over 56 days-the duration of some standard soil toxicity tests-in three soils amended with 500 mg/kg Cu as nanometer-sized CuO (nano), micrometer-sized CuO (micrometer), or Cu(NO3)2 (salt). In the CuO-amended soils, the log Cu2+ activity was initially low (minimum -9.48) and increased with time (maximum -5.20), whereas in the salt-amended soils it was initially high (maximum -4.80) and decreased with time (minimum -6.10). The Cu2+ activity in the nano-amended soils was higher than in the micrometer-amended soils for at least the first 11 days, and lower than in the salt-amended soils for at least 28 d. The pH, and dissolved Ca and Mg concentrations in the CuO-amended soils were similar, but the salt-amended soils had lower pH for at least 14 d, and higher Ca and Mg concentrations throughout the test. Soil pretreatments such as leaching and aging prior to toxicity tests are suggested.
Keywords: Calcium; Metal nanoparticles; Micrometers; Chemical forms; Different effects; Metal oxide nanoparticles; Mg concentrations; Nanometer-sized particles; Reference material; Soil solution chemistry; Soil toxicity tests; Soil moisture; copper; copper oxide; copper compound; nanotechnology; particle size; pH; soil amendment; toxicity test; article; light scattering; particle size; pH; soil amendment; soil analysis; soil pollution; transmission electron microscopy; Cations; Copper; Hordeum; Hydrogen-Ion Concentration; Nanoparticles; Particle Size; Powders; Reference Standards; Soil; Soil Pollutants; Solubility; Solutions; Time Factors; Toxicity Tests

Enhancing biomass production and yield by maintaining enhanced capacity for CO2 uptake in response to elevated CO2 - Dahal, Keshav; Weraduwage, Sarathi M.; Kane, Khalil; Rauf, Shezad A.; Leonardos, Evangelos D.; Gadapati, Winona; Savitch, Leonid; Singh, Jas; Marillia, Elizabeth-France; Taylor, David C.; Micallef, Malgre C.; Knowles, Vicki; et al. (Canadian Journal of Plant Science, 2014)
Using four model plants, two members of the Gramineae, rye and wheat, and two Brassicaceae, Brassica napus and Arabidopsis thaliana, two fundamental approaches were exploited to determine how regulating source-sink development would alter photosynthesis, productivity and yield during long-term acclimation to elevated CO2. In one approach we exploited the cold acclimation response of winter wheat, rye and B. napus. In the other approach we modified the dark respiration in A. thaliana to alter availability of respiratory substrates required for anabolic processes, such as fatty acid metabolism, thus reducing sink limitations on canopy photosynthesis at elevated CO2. Taken together, the data show the importance of maintaining strong demand from active sinks when the aboveground canopy is being exposed to elevated levels of the primary substrate of photosynthesis, CO2.
Keywords: acclimation; carbon dioxide; cereal; crop yield; dicotyledon; photosynthesis; phytomass; productivity; source-sink dynamics

Loading due to interaction of waves with colinear and oblique currents - Zaman, M. Hasanat; Baddour, Emile (Ocean Engineering, 2014)
A study on the loading of an oblique surface wave and a surface current field on a fixed vertical slender cylinder in a 3D flow frame is illustrated in the present paper. The three dimensional expressions describing the characteristics of the combined wave-current field in terms of mass, momentum and energy flux conservation equations are formulated. The parameters before the interaction of the oblique wave-free uniform current and current-free wave are used to formulate the kinematics of the flow field. These expressions are also employed to formulate and calculate the loads imparted by the wave-current combined flow on a bottom mounted slender vertical cylinder. In the present study two different situations are assumed where current is uniform over depth and also acting over a layer of fluid that extends from the free surface to a specified finite depth. In this paper we extend the approach considered in Zaman and Baddour (2004) for the wave-current analysis. Morison et al. (1950) equation is deployed for the load computations in all cases. The above models are utilized to compute the loads and moments on a slender cylinder for a wave with varying range of incidence current field.
Keywords: 3D wave-current field; Superposition model; Wave–current loading; Moments

The WIRCam deep survey: II. Mass selected clustering - Bielby, R. M.; Gonzalez-Perez, V.; McCracken, H. J.; Ilbert, O.; Daddi, E.; Le Fèvre, O.; Hudelot, P.; Kneib, J. -P.; Mellier, Y.; Willott, C. (Astronomy and Astrophysics, 2014)
We present an analysis of the clustering of galaxies from z ≈ 2 to the present day using the WIRCam Deep Survey (WIRDS). WIRDS combines deep optical data from the CFHTLS Deep fields with its own deep near-infrared data, providing a photometric data-set over an effective area of 2.4 deg2, from which accurate photometric redshifts and stellar masses can be estimated. We use the data to calculate the angular correlation function for galaxy samples split by star-formation activity, stellar mass and redshift. Using WIRDS with its large total area and multiple fields gives a low cosmic variance contribution to the error, which we estimate to be less than ~2.8%. Based on power-law fits, we estimate the real-space clustering for each sample, determining clustering lengths and power-law slopes. For galaxies selected by constant mass, we find that the clustering scale shows no evolution up to z ≈ 2. Splitting the galaxy sample by mass, we see a consistent trend for higher mass galaxies to have larger clustering scales at all redshifts considered. We use our results to test the galform semi-analytical model of galaxy formation and evolution. The observed trends are well matched by the model galaxies for both the redshift evolution and the mass dependence of the galaxy clustering. We split the galaxy population into passive and star-forming populations based on rest-frame dust-corrected NUV-r colours. We find that the passive galaxy populations show a significantly larger clustering scale at all redshifts than the star-forming population below masses of M~ 1011 h-1M⊙, showing that even at z ≈ 2 passive galaxies exist in denser environments than the bulk of the star-forming galaxy population. For star-forming galaxies with stellar masses of M ≳ 1011 h-1M⊙, we find a clustering strength of ~8 h-1 Mpc across all redshifts, comparable to the measurements for the passive population. Additionally, for star-forming galaxies we see that clustering strength increases for higher stellar mass systems, however little sign of a mass dependence in passive galaxies is observed over the range in stellar mass that is probed. Comparing our results to the model galaxy population produced by galform, we find a qualitative good agreement between the model predictions and the observed clustering. Finally, we investigate the connection between galaxy stellar mass and dark matter halo mass, showing a clear correlation between the two in both the WIRDS data and the galform predictions.
Keywords: Forecasting; Photometry; Stars; Surveys; Angular correlations; Clustering strength; Galaxies: evolutions; Galaxies:high-redshift; Galaxy formations; Large scale structure of universe; Semi-analytical model; Star forming galaxy; Galaxies

The Next Generation Virgo Cluster Survey. VIII. The spatial distribution of globular clusters in the virgo cluster - Durrell, P.R.; Côte, P.; Peng, E.W.; Blakeslee, J.P.; Ferrarese, L.; Mihos, J.C.; Puzia, T.H.; Lançon, A.; Liu, C.; Zhang, H.; Cuillandre, J.-C.; McConnachie, A.; et al. (The Astrophysical Journal, 2014)
We report on a large-scale study of the distribution of globular clusters (GCs) throughout the Virgo cluster, based on photometry from the Next Generation Virgo Cluster Survey (NGVS), a large imaging survey covering Virgo's primary subclusters (Virgo A = M87 and Virgo B = M49) out to their virial radii. Using the g ′ o, (g ′ - i ′)o color-magnitude diagram of unresolved and marginally resolved sources within the NGVS, we have constructed two-dimensional maps of the (irregular) GC distribution over 100 deg2 to a depth of g ′ o =24.We present the clearest evidence to date showing the difference in concentration between red and blue GCs over the full extent of the cluster, where the red (more metal-rich) GCs are largely located around the massive early-type galaxies in Virgo, while the blue (metal-poor) GCs have a much more extended spatial distribution with significant populations still present beyond 83′ (~215 kpc) along the major axes of both M49 and M87. A comparison of our GC maps to the diffuse light in the outermost regions of M49 and M87 show remarkable agreement in the shape, ellipticity, and boxiness of both luminous systems. We also find evidence for spatial enhancements of GCs surrounding M87 that may be indicative of recent interactions or an ongoing merger history. We compare the GC map to that of the locations of Virgo galaxies and the X-ray intracluster gas, and find generally good agreement between these various baryonic structures.We calculate the Virgo cluster contains a total population of NGC = 67,300±14,400, of which 35% are located in M87 and M49 alone. For the first time, we compute a cluster-wide specific frequency SN,CL = 2.8±0.7, after correcting for Virgo's diffuse light. We also find a GC-to-baryonic mass fraction εb = 5.7 ± 1.1 × 10-4 and a GC-to-total cluster mass formation efficiency εt = 2.9 ± 0.5 × 10-5, the latter values slightly lower than but consistent with those derived for individual galactic halos. Taken as a whole, our results show that the production of the complex structures in the unrelaxed Virgo cluster core (including the production of the diffuse intracluster light) is an ongoing and continuing process.

Evaluating collagen morphology and pathological lipid deposition using multiphoton image statistics - Mostaço-Guidolin, Leila B.; Ko, Alex C.-T.; Wang, Fei; Tian, Hong; Hewko, Mark; Shiomi, Masashi; Major, Arkady; Sowa, Michael G. (Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 2014)
In this study we present a novel image analysis methodology to quantify and to classify morphological details in tissue collagen fibril organization and lipid deposition. Co-localized collagen (second harmonic, SHG) and lipid (coherent Raman, CARS) images of atherosclerotic artery walls were acquired by a supercontinuum-powered multi-modal nonlinear microscope. Textural features based on the first-order statistics (FOS) and gray level co-occurrence matrix (GLCM) parameters were extracted from the SHG and CARS images. Multi-group classifications based on support vector machine of SHG and CARS images were subsequently performed to investigate the potential of texture analysis in providing quantitative descriptors of structural and compositional changes during disease progression. Using a rabbit model, different collagen remodeling and lipid accumulation patterns in disease tissues can be successfully tracked using these image statistics, thus providing a robust foundation for classification. When the variation of the CARS image features were tracked against the age of the rabbit, it was noticed that older animals (advanced plaques) present a more complex necrotic core containing high-lipid extracellular structures with various shapes and distribution. With combined FOS and GLCM texture statistics, we achieved reliable classification of SHG and CARS images acquired from atherosclerotic arteries with >90% accuracy, sensitivity and specificity. The proposed image analysis methodology can also be applied in a wide range of applications to evaluate conditions involving collagen re-modeling and prominent lipid accumulation.
Keywords: Coherent scattering; Collagen; Deposition; Image analysis; Textures; Tissue; Compositional changes; Disease progression; Extracellular structure; First-order statistics; Gray level co occurrence matrix(GLCM); Lipid accumulations; Multi-group classifications; Sensitivity and specificity; Image texture

Seasonal and extreme precipitation characteristics for the watersheds of the Canadian Prairie Provinces as simulated by the NARCCAP multi-RCM ensemble - Khaliq, M. N.; Sushama, L.; Monette, A.; Wheater, H. (Climate Dynamics, 2014)
This study evaluates projected changes to characteristics of winter, spring, summer and fall seasonal precipitation and rain and snow dominated daily precipitation extremes for 47 watersheds, located mainly in the Alberta, Saskatchewan and Manitoba provinces of Canada, using a multi-Regional Climate Model (RCM) ensemble available through the North American Regional Climate Change Assessment Program. The set of simulations considered includes those performed with the six participating RCMs for the 1980-2004 period driven by National Centre for Environmental Prediction reanalysis II and those driven by four Atmosphere-Ocean General Circulation Models (AOGCMs) for the 1971-2000 and 2041-2070 periods. For precipitation extremes, regional frequency analysis is used to develop projected changes to selected 10-, 30- and 50-year return levels of rain and snow dominated extremes (i.e. RDEs and SDEs) separately. The uncertainties due to internal dynamics and physics of the RCMs and those due to the lateral boundary data from driving AOGCMs are studied at the watershed level and evaluated in terms of coefficient of variation on the basis of a multi-RCM ensemble. In general, the structural uncertainty appears to be larger than that associated with the choice of the driving AOGCM for most of the precipitation characteristics considered. Analyses of multi-RCM ensemble-averaged projected changes to mean seasonal precipitation and various return levels of RDEs and SDEs show an increase over nearly all the study domain. The changes to seasonal precipitation are not generally found statistically significant at 5 % significance level but those for RDEs and SDEs are found significant more often for return levels of smaller return period (10-year) compared to those of larger return period (50-year). It is expected that changes in seasonal and extreme precipitation characteristics will have important implications for managing regional water security-related issues in the Canadian Prairie Provinces.
Keywords: Canadian Prairie Provinces; Climate change; Precipitation extremes; Regional climate models; Regional frequency analysis; Seasonal precipitation

A determination of Planck's constant using the NRC watt balance - Sanchez, C. A.; Wood, B. M.; Green, R. G.; Liard, J. O.; Inglis, D. (Metrologia, 2014)
We have measured Planck's constant and have obtained a value of 6.626 070 34(12) × 10-34 J s. To our knowledge this measurement of h has the lowest uncertainty reported to date. This result has been obtained from measurements of four masses of different material and nominal values varying from 1 kg to 250 g. The experimental procedures and the measurement uncertainties are described in detail.
Keywords: Engineering; Metallurgical engineering; Experimental procedure; Measurement uncertainty; Measurements of; Nominal values; Planck constants; Planck's constants; Watt balance; Uncertainty analysis

Effects of various dietary factors on astaxanthin absorption in Atlantic salmon (Salmo salar) - Chimsung, Noppawan; Tantikitti, Chutima; Milley, Joyce E.; Verlhac-Trichet, Viviane; Lall, Santosh P. (Aquaculture Research, 2014)
The experiment was designed to investigate the dietary factors that might enhance or interfere with astaxanthin (Ax) absorption in salmon including potentially interfering factors such as certain carotenoids (zeaxanthin and lutein), plant sterols, fibre and enhancing compounds such as cholesterol and vitamin E. Two hundred and eighty-eight salmon (778 ± 78 g) were reared in sea water under controlled conditions and fed practical experimental diets. The experimental diets were supplemented with 40 mg Ax kg-1, in addition to various dietary factors, including cholesterol (2%), vitamin E (450 IU kg-1), wheat bran (5%), lutein (40 mg kg-1), zeaxanthin (40 mg kg-1) and phytosterol (2%). After 26 days of feeding, blood was collected and plasma was separated to determine the plasma Ax concentration. Ax was not detected in the plasma of fish fed the non-pigmented diet. Fish fed diet containing 2% cholesterol significantly improved Ax absorption, which was reflected in the higher Ax concentration in plasma of Atlantic salmon. Other supplements including vitamin E, wheat bran, lutein, zeaxanthin and phytosterols in diet had no significant effect on plasma Ax concentration. Fish fed diet containing 2% cholesterol significantly increased cholesterol concentration in fish plasma. Phytosterol had no benefit to lower cholesterol plasma level in fish fed 2% phytosterol-supplemented diet.
Keywords: Absorption; Astaxanthin; Atlantic salmon; Carotenoid; Cholesterol; Fibre; Lutein; Phytosterol; Vitamin E; Zeaxanthin

The search for faint radio supernova remnants in the outer Galaxy: Five new discoveries - Gerbrandt, Stephanie; Foster, Tyler J.; Kothes, Roland; Geisbüsch, Jörn; Tung, Albert (Astronomy and Astrophysics, 2014)
Context. High resolution and sensitivity large-scale radio surveys of the Milky Way are critical in the discovery of very low surface brightness supernova remnants (SNRs), which may constitute a significant portion of the Galactic SNRs still unaccounted for (ostensibly the "missing SNR problem"). Aims. The overall purpose here is to present the results of a systematic, deep data-mining of the Canadian Galactic plane Survey (CGPS) for faint, extended non-thermal and polarized emission structures that are likely the shells of uncatalogued SNRs. Methods. We examine 5 × 5 degree mosaics from the entire 1420 MHz continuum and polarization dataset of the CGPS after removing unresolved "point" sources and subsequently smoothing them. Newly revealed extended emission objects are compared to similarly prepared CGPS 408 MHz continuum mosaics, as well as to source-removed mosaics from various existing radio surveys at 4.8 GHz, 2.7 GHz, and 327 MHz, to identify candidates with non-thermal emission characteristics. We integrate flux densities at each frequency to characterise the radio spectra behaviour of these candidates. We further look for mid- and high-frequency (1420 MHz, 4.8 GHz) ordered polarized emission from the limb brightened "shell"-like continuum features that the candidates sport. Finally, we use IR and optical maps to provide additional backing evidence. Results. Here we present evidence that five new objects, identified as filling all or some of the criteria above, are strong candidates for new SNRs. These five are designated by their Galactic coordinate names G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8, and G160.1-1.1. The radio spectrum of each is presented, highlighting their steepness, which is characteristic of synchrotron radiation. CGPS 1420 MHz polarization data and 4.8 GHz polarization data also provide evidence that these objects are newly discovered SNRs. These discoveries represent a significant increase in the number of SNRs known in the outer Galaxy second quadrant of longitude (90° < ℓ < 180°), and suggests that deep mining of other current and future Milky Way surveys will find even more objects and help to reconcile the difference between expected numbers of Galactic SNRs and the smaller number of currently known SNRs.
Keywords: Image processing; Optical data processing; Polarization; Supernovae; Surveys; Canadian galactic plane surveys; Galactic coordinates; ISM: supernova remnants; Nonthermal emission; Polarized emissions; Radio continuum: ISM; Surface brightness; Techniques: image processing; Galaxies

Synthesis of Ni/SiO2 nanocomposites for tunable electromagnetic absorption - Gong, Chungong; Wang, Xinwin; Zhang, Xuefeng; Zhao, Xiaowei; Meng, Hongjie; Jia, Yongshuai; Zhang, Jingwei; Zhang, Zhijun (Materials Letters, 2014)
Composition tunable Ni/SiO2 nanocomposites were synthesized via a facile one-step wet chemical process. The morphology and size of Ni as well as the magnetic and electromagnetic properties of the hybrid materials are all highly dependent on the SiO2 content. The electromagnetic wave absorption of the Ni/SiO2 nanocomposites with optimal composition is satisfactory. The enhanced microwave absorption might attribute to the enhanced interfacial polarization between Ni and SiO2 nanoparticles and the appropriate match of the hybrid nanocomposite.
Keywords: Ni/SiO2; Nanocomposites; Magnetic materials; Microwaveabsorption

The origin of organic emission in NGC 2071 - van Kempen, T. A.; McCoey, C.; Tisi, S.; Johnstone, D.; Fich, M. (Astronomy and Astrophysics, 2014)
Context. The physical origin behind organic emission lines in embedded low-mass star formation has been fiercely debated over the last two decades. A multitude of scenarios have been proposed, from a hot corino to PDRs on cavity walls to shock excitation. Aims. The aim of this paper is to determine the location and the corresponding physical conditions of the gas responsible for organics emission lines. The outflows around the small protocluster NGC 2071 are an ideal testbed that can be used to differentiate between various scenarios. Methods. Using Herschel-HIFI and the Submillimeter Array, observations of CH3OH, H2CO, and CH3CN emission lines over a wide range of excitation energies were obtained. Comparisons to a grid of radiative transfer models provide constraints on the physical conditions. Comparison to H2O line shape is able to trace gas-phase synthesis versus a sputtered origin. Results. Emission of organics originates in three separate spots: the continuum sources IRS 1 ("B") and IRS 3 ("A") and a new outflow position ("F"). Densities are above 107cm-3and temperatures between 100 K and 200 K. CH3OH emission observed with HIFI originates in all three regions and cannot be associated with a single region. Very little organic emission originates outside of these regions. Conclusions. Although the three regions are small (<1500 AU), gas-phase organics likely originate from sputtering of ices as a result of outflow activity. The derived high densities (>107cm-3) are likely a requirement for organic molecules to survive from being immediately destroyed by shock products after evaporation. The lack of spatially extended emission confirms that organic molecules cannot (re-)form through gas-phase synthesis, as opposed to H2O, which shows strong line wing emission. The lack of CH3CN emission at "F" is evidence for a different history of ice processing because of the absence of a protostar at that location and recent ice mantle evaporation.
Keywords: Circumstellar matters; Organic emissions; Stars: formation; Stars: protostars; Submillimeter: isms

Signatures of the continuum electron phase in molecular strong-field photoelectron holography - Meckel, M.; Staudte, A.; Patchkovskii, S.; Villeneuve, D. M.; Corkum, P. B.; Dörner, R.; Spanner, M. (Nature Physics, 2014)
Laser-driven electron recollision is at the heart of the rapidly growing field of attosecond science. The recollision wavepacket is qualitatively described within the strong-field approximation, which commonly assumes tunnelling ionization and plane-wave propagation of the liberated electron in the continuum. However, with increasing experimental sophistication, refinements to this simple model have become necessary. Through careful modelling and measurements of laser-induced recollision holography using aligned N 2 molecules, we demonstrate that the continuum electron wavepacket already carries a non-trivial spatial phase structure immediately following ionization. This effect is of rather general character: any molecule and any non-isotropic system that is ionized by a strong laser field will exhibit an offset in the phase of the continuum electron wavepacket. Specifically, this has important implications for any coherent scattering process in molecules, such as high-harmonic generation or laser-induced electron holography.

Physical and chemical characteristics of l1689-smm16, an oscillating prestellar core in ophiuchus - Chitsazzadeh, S.; Di Francesco, J.; Schnee, S.; Friesen, R. K.; Shimajiri, Y.; Langston, G. I.; Sadavoy, S. I.; Bourke, T. L.; Keto, E. R.; Pineda, J. E.; Takakuwa, S.; Tatematsu, K. (The Astrophysical Journal, 2014)
We present single-dish observations of the L1689-SMM16 core in the Ophiuchus molecular cloud in NH3 (1, 1) and (2, 2) emission using the Green Bank Telescope, in N2H+ (1-0) emission using the Nobeyama Radio Observatory, and in NH2D (), HCN (1-0), HNC (1-0), H 13CO+ (1-0), and HCO+ (1-0) emission using the Mopra telescope. The morphologies of the integrated NH3 (1, 1) and N2H+ (1-0) emission well match that of 250 μm continuum emission. Line widths of NH3 (1, 1) and N2H+ (1-0) show the presence of transonic turbulence across the core. Jeans and virial analyses made using updated measurements of core mass and size confirm that L1689-SMM16 is prestellar, i.e., gravitationally bound. It also has accumulated more mass compared to its corresponding Jeans mass in the absence of magnetic fields and therefore is a "super-Jeans" core. The high levels of X(NH 3)/X(N2H+) and deuterium fractionation reinforce the idea that the core has not yet formed a protostar. Comparing the physical parameters of the core with those of a Bonnor-Ebert sphere reveals the advanced evolutionary stage of L1689-SMM16 and shows that it might be unstable to collapse. We do not detect any evidence of infall motions toward the core. Instead, red asymmetry in the line profiles of HCN (1-0) and HNC (1-0) indicates the expansion of the outer layers of the core at a speed of 0.2 km s -1 to 0.3 km s-1. For a gravitationally bound core, expansion in the outer layers might indicate that the core is experiencing oscillations.
Keywords: ISM: kinematics and dynamics; ISM: molecules; ISM: structure; radio lines: ISM; stars: formation

Shuttle-Cargo fusion molecules of transport peptides and the hD 2/3 receptor antagonist fallypride : a feasible approach to preserve ligand-receptor binding? - Wängler, Carmen; Chowdhury, Shafinaz; Höfner, Georg; Djurova, Petia; Purisima, Enricho O.; Bartenstein, Peter; Wängler, Björn; Fricker, Gert; Wanner, Klaus T.; Schirrmacher, Ralf (Journal of Medicinal Chemistry, 2014)
To determine if the conjugation of a small receptor ligand to a peptidic carrier to potentially facilitate transport across the blood-brain barrier (BBB) by "molecular Trojan horse" transcytosis is feasible, we synthesized several transport peptide-fallypride fusion molecules as model systems and determined their binding affinities to the hD2 receptor. Although they were affected by conjugation, the binding affinities were found to be still in the nanomolar range (between 1.5 and 64.2 nM). In addition, homology modeling of the receptor and docking studies for the most potent compounds were performed, elucidating the binding modes of the fusion molecules and the structure elements contributing to the observed high receptor binding. Furthermore, no interaction between the hybrid compounds and P-gp, the main excretory transporter of the BBB, was found. From these results, it can be inferred that the approach to deliver small neuroreceptor ligands across the BBB by transport peptide carriers is feasible.
Keywords: 3 [3 [(1 allylpyrrolidin 2 yl)methylcarbamoyl]4,5 dimethoxy phenyl] propyl thiol; butaclamol; carrier protein; chlorpromazine; cyclosporin A; dopamine 2 receptor; dopamine 2 receptor blocking agent; dopamine 3 receptor; dopamine 3 receptor blocking agent; drug carrier; fallypride; fluorine 18; gallium 68; haloperidol; ligand; maleimide; multidrug resistance protein; raclopride; transferrin receptor; unclassified drug; amino acid sequence; article; binding affinity; binding site; blood brain barrier; conjugate; conjugation; derivatization; drug synthesis; environmental temperature; freeze drying; high performance liquid chromatography; human; in vitro study; isotope labeling; ligand binding; membrane permeability; molecular docking; molecular model; molecule; nuclear localization signal; peptide synthesis; pH; positron emission tomography; reaction time; receptor binding; stereospecificity; transcytosis; Amino Acid Sequence; Benzamides; Biological Transport; Blood-Brain Barrier; Carrier Proteins; Dopamine Antagonists; Humans; Ligands; Models, Molecular; Molecular Docking Simulation; Molecular Sequence Data; P-Glycoprotein; Receptors, Dopamine D2; Receptors, Transferrin; Transcytosis

Amphiphobic surfaces from functionalized TiO2 nanotube arrays - Farsinezhad, Samira; Waghmare, Prashant R.; Wiltshire, Benjamin D.; Sharma, Himani; Amiri, Saeid; Mitra, Sushanta K.; Shankar, Karthik (RSC Advances, 2014)
Vertically-oriented, self-organized TiO2 nanotube arrays (TNAs) are a highly ordered n-type semiconducting nanoarchitecture with a wide range of potential applications. We generated low energy surfaces repellent to a broad spectrum of liquids by functionalizing TNAs using monolayers of two different fluorinated hydrocarbon molecules: perfluorononanoic acid (PFNA) and 1H, 1H′, 2H, 2H′-perfluorodecyl phosphonic acid (PFDPA). Nanotubes of two different outer diameters (50 nm and 130 nm) were studied and their wetting behavior analyzed in liquids belonging to different solvent classes to infer the nature of the wetting states. We show that the wetting behavior of perfluorinated monolayer-functionalized TNAs in polar liquids is explained by fakir or Cassie-states whilst the wetting behavior of bare nanotubes in every liquid is explained by Wenzel-type states. On the other hand, a transition between the Cassie and Wenzel states due to closed pores in the TNA architecture dictates the wetting behavior of functionalized TNAs in apolar liquids. The wetting behavior of functionalized TNAs is understood considering the synergistic effect of geometric and chemical surface modification. PFDPA-functionalized TNAs were found to be resilient to 24 hours of exposure to water and ethylene glycol at a static fluid pressure of 0.105 MPa, and are one step closer towards the realization of a mechanically robust omniphobic surface. At the same time, an understanding of wetting behavior will be useful in the design and optimization of a wide range of interface-sensitive devices such as metal oxide nanotube/nanopore array based sensors, implants, flow-through membranes, photocatalysts and heterojunction solar cells.
Keywords: Ethylene glycol; Heterojunctions; Liquids; Monolayers; Nanotubes; Chemical surface modification; Design and optimization; Fluorinated hydrocarbons; Heterojunction solar cells; Interface-sensitive; Low energy surfaces; Mechanically robust; Perfluorononanoic acids; Wetting

Linewidth-narrowing phenomena with intersubband cavity polaritons - Murphy, Francis J.; Bak, Alexy O.; Matthews, Mary; Dupont, Emmanuel; Amrania, Hemmel; Phillips, Chris C. (Physical Review B - Condensed Matter and Materials Physics, 2014)
Absorption spectra of strongly coupled intersubband cavity polaritons have been measured, using a tunable midinfrared quantum cascade laser, with high angular and spectral resolution. Pronounced linewidth narrowing of the polaritons around the anticrossing was found, with polariton linewidths narrower (4.2 meV) than both the bare intersubband transition linewidth and empty cavity linewidth (6.2 and 6 meV, respectively), at room temperature. This is due to variations in the degree of spatial averaging of the in-plane quantum-well disorder as the polariton's extended coherence length is increased by the photonic coupling over the value corresponding to the bare intersubband transition coherence length.

Hydrophobic triaryl-substituted β-lactams as activity-based probes for profiling eukaryotic enzymes and host-pathogen interactions - Nasheri, Neda; McKay, Craig S.; Fulton, Kelly; Twine, Susan; Powdrill, Megan H.; Sherratt, Allison R.; Pezacki, John Paul (ChemBioChem, 2014)
ABPP with β-lactams: We identified the eukaryotic targets of β-lactam-containing compounds by activity-based protein profiling. Using this method, we demonstrated that β-lactam-based activity probes can be applied to identify differentially active enzymes in different cell lines and during hepatitis C virus replication.
Keywords: beta lactam derivative; enzyme; eukaryote; fluorescence; gel electrophoresis; host pathogen interaction; hydrophobicity; liquid chromatography; molecular probe; protein analysis; tandem mass spectrometry

Sorption and capillary condensation in wood and the moisture content of red pine - Wang, Jieying; Mukhopadhyaya, Phalguni; Morris, Paul I. (Journal of Building Physics, 2014)
The major purpose of this study is to improve hygrothermal simulation of wood responses to environmental vapor and moisture conditions under high relative humidity conditions. The article first reviews moisture property-related wood microstructures, sorption behavior, the concept of fiber saturation point, the potential for vapor to condense in wood under high relative humidity conditions, the measurement of equilibrium moisture content using traditional sorption methods, and the use of pressure plate test method at relative humidities above 95%. It then summarizes the results of equilibrium moisture content measurements for red pine sapwood at high relative humidity conditions using both sorption and pressure plate methods, with capillary saturation as maximum moisture content. It also discusses a number of wood microstructure and end-use-related factors that could influence the moisture content in service and the measurement of equilibrium moisture content in laboratory. Inconsistencies were found with other equilibrium moisture content data using the pressure plate test method.
Keywords: Atmospheric humidity; Digital storage; Microstructure; Moisture; Sorption; Testing; Vapors; Equilibrium moisture contents; High relative humidities; Hygrothermal; Moisture storage; Pressure plate methods; Red pines; Moisture determination; Humidity; Microstructure; Moisture Content; Wood Products

Using Monte Carlo ray tracing simulations to model the quantum harmonic oscillator modes observed in uranium nitride - Lin, J. Y. Y.; Aczel, A. A.; Abernathy, D. L.; Nagler, S. E.; Buyers, W. J. L.; Granroth, G. E. (Physical Review B - Condensed Matter and Materials Physics, 2014)
Recently an extended series of equally spaced vibrational modes was observed in uranium nitride (UN) by performing neutron spectroscopy measurements using the ARCS and SEQUOIA time-of-flight chopper spectrometers [A. A. Aczel, Nat. Commun. 3, 1124 (2012)2041-172310.1038/ncomms2117]. These modes are well described by three-dimensional isotropic quantum harmonic oscillator (QHO) behavior of the nitrogen atoms, but there are additional contributions to the scattering that complicate the measured response. In an effort to better characterize the observed neutron scattering spectrum of UN, we have performed Monte Carlo ray tracing simulations of the ARCS and SEQUOIA experiments with various sample kernels, accounting for nitrogen QHO scattering, contributions that arise from the acoustic portion of the partial phonon density of states, and multiple scattering. These simulations demonstrate that the U and N motions can be treated independently, and show that multiple scattering contributes an approximate Q-independent background to the spectrum at the oscillator mode positions. Temperature-dependent studies of the lowest few oscillator modes have also been made with SEQUOIA, and our simulations indicate that the T dependence of the scattering from these modes is strongly influenced by the uranium lattice.

MOST light-curve analysis of the γ Doradus pulsator hr 8799, showing resonances and amplitude variations - Sódor, Á.; Chené, A. -N.; De Cat, P.; Bognár, Zs.; Wright, D. J.; Marois, C.; Walker, G. A. H.; Matthews, J. M.; Kallinger, T.; Rowe, J. F.; Kuschnig, R.; Guenther, D. B.; et al. (Astronomy and Astrophysics, 2014)
Context. The central star of the HR 8799 system is a γ Doradus-type pulsator. The system harbours four planetary-mass companions detected by direct imaging, and is a good solar system analogue. The masses of the companions are not accurately known because the estimation depends greatly on the age of the system, which is also not known with sufficient accuracy. Asteroseismic studies of the star might help to better constrain the age of HR 8799. We organized an extensive photometric and multi-site spectroscopic observing campaign to study the pulsations of the central star. Aims. The aim of the present study is to investigate the pulsation properties of HR 8799 in detail via the ultra-precise 47 d nearly continuous photometry obtained with the Microvariability and Oscillations in STars (MOST) space telescope, and to find as many independent pulsation modes as possible, which is the prerequisite for an asteroseismic age determination. Methods. We carried out Fourier analysis of the wide-band photometric time series. Results. We find that resonance and sudden amplitude changes characterize the pulsation of HR 8799. The dominant frequency is always at f1 = 1.978 d-1.Many multiples of one-ninth of the dominant frequency appear in the Fourier spectrum of the MOST data: n/9 f 1, where n = {1,2,3,4,5,6,7,8,9,10,13,14,17,18}. Our analysis also reveals that many of these peaks show strong amplitude decrease and phase variations even on the 47 d time scale. The dependencies between the pulsation frequencies of HR 8799 make the planned subsequent asteroseismic analysis rather difficult. We point out some resemblance between the light curve of HR 8799 and the modulated pulsation light curves of Blazhko RR Lyrae stars.
Keywords: Fourier analysis; Photometry; Amplitude changes; Amplitude variations; Dominant frequency; Micro-variability; Pulsation frequency; Stars: individual; Stars: oscillation; Techniques: photometric; Stars

Calculation of equivalent initial flaw size distributions for multiple-site damage - Renaud, G.; Liao, M.; Bombardier, Y. (55th AIAA/ASMe/ASCE/AHS/SC Structures, Structural Dynamics, and Materials Conference, 2014)
An optimization based methodology was developed to calculate equivalent initial flaw sizes (EIFS) consistent with multiple-site damage in-service findings. The new methodology is compared with a simplified single-crack engineering approach that was previously used for a structural risk analysis. Calculated EIFS, fatigue life, and risk results resulting from both approaches are compared for the Royal Canadian Air Force in-service damage and nil findings at the CC-130 CW-1 location. For the considered case, the results suggest that the simplified engineering approach overestimates the probability of failure.

Molecular outflows driven by low-mass protostars. I. Correcting for underestimates when measuring outflow masses and dynamical properties - Dunham, Michael M.; Arce, Hector G.; Mardones, Diego; Lee, Jeong-Eun; Matthews, Brenda C.; Stutz, Amelia M.; Williams, Jonathan P. (The Astrophysical Journal, 2014)
We present a survey of 28 molecular outflows driven by low-mass protostars, all of which are sufficiently isolated spatially and/or kinematically to fully separate into individual outflows. Using a combination of new and archival data from several single-dish telescopes, 17 outflows are mapped in 12CO (2-1) and 17 are mapped in 12CO (3-2), with 6 mapped in both transitions. For each outflow, we calculate and tabulate the mass (M flow), momentum (P flow), kinetic energy (E flow), mechanical luminosity (L flow), and force (F flow) assuming optically thin emission in LTE at an excitation temperature, T ex, of 50 K. We show that all of the calculated properties are underestimated when calculated under these assumptions. Taken together, the effects of opacity, outflow emission at low velocities confused with ambient cloud emission, and emission below the sensitivities of the observations increase outflow masses and dynamical properties by an order of magnitude, on average, and factors of 50-90 in the most extreme cases. Different (and non-uniform) excitation temperatures, inclination effects, and dissociation of molecular gas will all work to further increase outflow properties. Molecular outflows are thus almost certainly more massive and energetic than commonly reported. Additionally, outflow properties are lower, on average, by almost an order of magnitude when calculated from the 12CO (3-2) maps compared to the 12CO (2-1) maps, even after accounting for different opacities, map sensitivities, and possible excitation temperature variations. It has recently been argued in the literature that the 12CO (3-2) line is subthermally excited in outflows, and our results support this finding.

Strict limit on in-plane ordered magnetic dipole moment in URu2 Si2 - Ross, K. A.; Harriger, L.; Yamani, Z.; Buyers, W. J. L.; Garrett, J. D.; Menovsky, A. A.; Mydosh, J. A.; Broholm, C. L. (Physical Review B - Condensed Matter and Materials Physics, 2014)
Neutron diffraction is used to examine the polarization of weak static antiferromagnetism in high quality single crystalline URu2Si2. As previously documented, elastic Bragg-like diffraction develops for temperature T<THO=17.5 K at q=(100) but not at wave vector transfer q=(001). The peak width indicates correlation lengths ξc=230(12) Å and ξa=240(15) Å. The integrated intensity of the T-dependent peaks corresponds to a sample averaged c-oriented staggered moment of μc=0.022(1)μB at T=1.7 K. The absence of T-dependent diffraction at q=(001) places a limit μ¥<0.0011μB on an f- or d-orbital-based in-plane staggered magnetic dipole moment, which is associated with multipolar orders proposed for URu2Si2.

On the correction, perturbation and modification of small field detectors in relative dosimetry - Papaconstadopoulos, P.; Tessier, F.; Seuntjens, J. (Physics in Medicine and Biology, 2014)
The purpose of this study was to derive a complete set of correction and perturbation factors for output factors (OF) and dose profiles. Modern small field detectors were investigated including a plastic scintillator (Exradin W1, SI), a liquid ionization chamber (microLion 31018, PTW), an unshielded diode (Exradin D1V, SI) and a synthetic diamond (microDiamond 60019, PTW). A Monte Carlo (MC) beam model was commissioned for use in small fields following two commissioning procedures: (1) using intermediate and moderately small fields (down to 2 × 2 cm2) and (2) using only small fields (0.5 × 0.5 cm2-2 × 2 cm2). In the latter case the detectors were explicitly modelled in the dose calculation. The commissioned model was used to derive the correction and perturbation factors with respect to a small point in water as suggested by the Alfonso formalism. In MC calculations the design of two detectors was modified in order to minimize or eliminate the corrections needed. The results of this study indicate that a commissioning process using large fields does not lead to an accurate estimation of the source size, even if a 2 × 2 cm2 field is included. Furthermore, the detector should be explicitly modelled in the calculations. On the output factors, the scintillator W1 needed the smallest correction (+0.6%), followed by the microDiamond (+1.3%). Larger corrections were observed for the microLion (+2.4%) and diode D1V (-2.4%). On the profiles, significant corrections were observed out of the field on the gradient and tail regions. The scintillator needed the smallest corrections (-4%), followed by the microDiamond (-11%), diode D1V (+13%) and microLion (-15%). The major perturbations reported were due to volume averaging and high density materials that surround the active volumes. These effects presented opposite trends in both OF and profiles. By decreasing the radius of the microLion to 0.85 mm we could modify the volume averaging effect in order to achieve a discrepancy less than 1% for OF and 5% for profiles compared to water. Similar results were observed for the diode D1V if the radius was increased to 1 mm.
Keywords: Monte Carlo methods; Alfonso formalism; perturbation; profile; small field; stereotactic; Dosimetry

Development and simulation of sulfur-doped graphene supported platinum with exemplary stability and activity towards oxygen reduction - Higgins, Drew; Hoque, Md Ariful; Seo, Min Ho.; Wang, Rongyue; Hassan, Fathy; Choi, Ja-Yeon; Pritzker, Mark; Yu, Aiping; Zhang, Jiujun; Chen, Zhongwei (Advanced Functional Materials, 2014)
Sulfur-doped graphene (SG) is prepared by a thermal shock/quench anneal process and investigated as a unique Pt nanoparticle support (Pt/SG) for the oxygen reduction reaction (ORR). Particularly, SG is found to induce highly favorable catalyst-support interactions, resulting in excellent half-cell based ORR activity of 139 mA mgPt -1 at 0.9 V vs RHE, significant improvements over commercial Pt/C (121 mA mgPt -1) and Pt-graphene (Pt/G, 101 mA mgPt -1). Pt/SG also demonstrates unprecedented stability, maintaining 87% of its electrochemically active surface area following accelerated degradation testing. Furthermore, a majority of ORR activity is maintained, providing 108 mA mg Pt -1, a remarkable 171% improvement over Pt/C (39.8 mA mgPt -1) and an 89% improvement over Pt/G (57.0 mA mg Pt -1). Computational simulations highlight that the interactions between Pt and graphene are enhanced significantly by sulfur doping, leading to a tethering effect that can explain the outstanding electrochemical stability. Furthermore, sulfur dopants result in a downshift of the platinum d-band center, explaining the excellent ORR activity and rendering SG as a new and highly promising class of catalyst supports for electrochemical energy technologies such as fuel cells.
Keywords: graphene; catalyst; electrochemistry; fuel cell; oxygen reduction

The penetration depth of chemical reactions in a thin-film Co 3O4 supercapacitor electrode - Vezvaie, M.; Kalisvaart, P.; Fritzsche, H.; Tun, Z.; Mitlin, D. (Journal of the Electrochemical Society, 2014)
An experiment designed to measure the thickness of an electrochemically active layer on the surface of a thin-film Co3O4 electrode shows that the entire thickness of the film, 40 nm in all, undergoes chemical changes. This was the case when the film was first exposed to pure water and later subjected to +1 VSCE in 0.01M KOH solution. Upon removal of the applied potential, the film reverted to a state that was nearly identical to the one it had before polarization.
Keywords: Electrodes; Electrolytic capacitors; Active Layer; Applied potentials; Chemical change; Exposed to; KOH solution; Pure water; Supercapacitor electrodes; Thickness of the film; Cobalt

Berberine decreases cholesterol levels in rats through multiple mechanisms, including inhibition of cholesterol absorption - Wang, Yanwen; Yi, Xin; Ghanam, Khadija; Zhang, Shuocheng.; Zhao, Tiantian; Zhu, Xuemei (Metabolism: Clinical and Experimental, 2014)
Objective The objective was to determine the mechanisms of action of berberine (BBR) on cholesterol homeostasis using in vivo and in vitro models. Methods Male Sprague-Dawley rats were fed the AIN-93G diet (normal control) or modified AIN-93G diet containing 28% fat, 2% cholesterol and 0.5% cholic acid with treatment of 0 (atherogenic control), 50, 100, and 150 mg/kg·d of BBR, respectively by gavaging in water for 8 weeks. Cholesterol absorption rate was measured with the dual stable isotope ratio method, and plasma lipids were determined using the enzymatic methods. Gene and protein expressions of Acyl-coenzyme A:cholesterol acyltransferase-2 were analyzed in vivo and in vitro. Cholesterol micellarization, uptake and permeability were determined in vitro. Results Rats on the atherogenic diet showed significantly hypercholesterolemic characteristics compared to normal control rats. Treatment with BBR in rats on the atherogenic diet reduced plasma total cholesterol and nonHDL cholesterol levels by 29%-33% and 31%-41%, respectively, with no significant differences being observed among the three doses. The fractional dietary cholesterol absorption rate was decreased by 40%-51%. Rats fed the atherogenic diet showed lower plasma triacylglycerol levels, and no changes were observed after the BBR treatment. BBR interfered with cholesterol micellarization, decreased cholesterol uptake by Caco-2 cells and permeability through Caco-2 monolayer. BBR also inhibited the gene and protein expressions of acyl-coenzyme A cholesterol acyltransferease-2 in the small intestine and Caco-2 cells. Conclusion BBR lowered blood cholesterol levels at least in part through inhibiting the intestinal absorption and further by interfering with intraluminal cholesterol micellarization and decreasing enterocyte cholesterol uptake and secretion.
Keywords: Acyl-coenzyme A:cholesterol acyltransferase-2; Berberine; Cholesterol absorption; Cholesterol micellarization; Rat; Anticholesteremic Agents; Caco-2 Cells; Cell Membrane Permeability; Cholesterol; Diet, Atherogenic; Dietary Supplements; Enterocytes; Gene Expression Regulation, Enzymologic; Hypercholesterolemia; Intestinal Absorption; Micelles; Random Allocation; Rats, Sprague-Dawley; Sterol O-Acyltransferase

Physics-based measurements, reflective measurements and meta-measurements for nonrigid and deformable shapes with application to structural proteomics and macromolecular docking - Paquet, Eric; De Youngster, Dela; Viktor, Herna; Petriu, Emil (CIVEMSA 2014 - 2014 IEEE Conference on Computational Intelligence and Virtual Environments for Measurement Systems and Applications, Proceedings, 2014)
Non-rigid shapes are generally known as objects where the three dimensional geometry may deform by internal and/or external forces. Deformable shapes are all around us, ranging from macromolecules, to natural objects such as the trees in the forest or the fruits in our gardens, and even human bodies. The development of measurements to accurately describe such non-rigid shapes has wide application. It follows that, when aiming to perform measurement of non-rigid shapes, one need to ensure that the intrinsic geometries are preserved in the presence of deformations. This paper introduces physics-based techniques for the measurements of such deformable shapes. Our work is based on the idea of heat propagation through a surface. Specifically, we introduce so-called multi-measurements to measure the distance between two points on an object and reflective measurements that allows for the exploration of a region around a point. Further, we introduce two novel meta-measurements that extend the bag of features concept. We illustrate our methodology in the context of structural proteomics and molecular docking.
Keywords: Deformation; Docking; Macromolecules; Molecular biology; Virtual reality; Bag of features; Deformable object; Geodesic distances; Heat kernel; isomorphism; Laplace-Beltrami operator; Medoids; multi-measurements; Physics-based; Measurements

Chemical generation of arsane and methylarsanes with amine boranes. Potentialities for nonchromatographic speciation of arsenic - Pitzalis, Emanuela; Onor, Massimo; Mascherpa, Marco Carlo; Pacchi, Giacomo; Mester, Zoltan; D'Ulivo, Alessandro (Analytical Chemistry, 2014)
The efficiency of chemical generation of arsanes from inorganic arsenic, monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), to arsane, AsH3, monomethylarsane, CH3AsH2 (MMA), and dimethylarsane, (CH3)2AsH (DMA), has been investigated in different reaction media with the aim to better elucidate the mechanisms controlling their generation process and to find the experimental conditions to implement a nonchromatographic arsenic speciation analytical method, which is based on the selective determination of some arsenic species. Studies were performed by continuous flow hydride generation coupled with atomic spectrometry (CF-HG-AS), using different reductants such as borane-ammonia (AB), borane-tert-butylamine (TBAB), and sodium tetrahydridoborate (THB) in HCl and HClO4 media, in the presence or absence of l-cysteine (Cys). The efficiency of HG processes for MMA and DMA is mainly controlled by the reactivity of the substrates with the borane, which could be strongly influenced by the formation of ion couples. The protonation of arsane did not play a significant role in the employed reaction system. By taking advantage of the different reactivity pattern of As species in selected generation conditions, DMAA and MMAA could be selectively determined in 0.5 and 10 M HClO4 solutions, respectively, in the presence of Cys, with AB as the reducing agent. The presence of Cys as a masking agent and the peculiar reducing properties of AB ensured a good control of interferences, as far as it has been observed for Co(II), Ni(II), Cu(II), Fe(II), Fe(III). The overall time needed to complete the prereduction step has been verified for MMAA and DMAA at different acidities in order to achieve the best selectivity. The selective determination of DMAA with AB/Cys in HClO4 has been optimized and applied to certified reference materials (CRMs) of natural waters CASS-4, SLRS-4, and NASS-4 (NRCC). The estimation of DMAA concentration allows us to correct the concentration of As(III) for the interference of DMAA in the selective determination of As(III) according to a selective HG method recently reported.
Keywords: Atomic spectrometry; Certified reference materials; Dimethylarsinic acids; Experimental conditions; Generation process; Hydride generations; Monomethylarsonic acids; Selective determination; Amino acids; Atomic spectroscopy; Chemical analysis; Chemical speciation; Hydrides; Process control; amine; arsenic; arsine; organoarsenic derivative; water; fractionation; isolation and purification; methodology; Chemical Fractionation

Magnetic doppler imaging of he-strong star HD 184927 - Yakunin, I.; Wade, G.; Bohlender, D.; Kochukhov, O.; Tsymbal, V. (Magnetic fields throughout stellar evolution, 2014)
We have employed an extensive new timeseries of Stokes I and V spectra obtained with the ESPaDOnS spectropolarimeter at the 3.6-m Canada-France-Hawaii Telescope to investigate the physical parameters, chemical abundance distributions and magnetic field topology of the slowly-rotating He-strong star HD 184927. We infer a rotation period of 9d.53071 ± 0.00120 from Hα, Hβ, LSD magnetic measurements and EWs of helium lines. We used an extensive NLTE TLUSTY grid along with the SYNSPEC code to model the observed spectra and find a new value of luminosity. In this poster we present the derived physical parameters of the star and the results of Magnetic Doppler Imaging analysis of the Stokes I and V profiles. Wide wings of helium lines can be described only under the assumption of the presence of a large, very helium-rich spot.

Suspended SOI waveguide with sub-wavelength grating cladding for mid-infrared - Soler Penadés, J.; Alonso-Ramos, C.; Khokhar, A. Z.; Nedeljkovic, M.; Boodhoo, L. A.; Ortega-Moñux, A.; Molina-Fernández, I.; Cheben, P.; Mashanovich, G. Z. (Optics Letters, 2014)
We present a new type of mid-infrared silicon-on-insulator (SOI) waveguide. The waveguide comprises a subwavelength lattice of holes acting as lateral cladding while at the same time allowing for the bottom oxide (BOX) removal by etching. The waveguide loss is determined at the wavelength of 3.8 μm for structures before and after being underetched using both vapor phase and liquid hydrofluoric acid (HF). A propagation loss of 3.4 dB/cm was measured for a design with a 300 nm grating period and 150 nm holes after partial removal (560 nm) of BOX by vapor phase HF etching. We also demonstrate an alternative design with 550 nm period and 450 nm holes, which allows a faster and complete removal of the BOX by liquid phase HF etching, yielding the waveguide propagation loss of 3.6 dB/cm.
Keywords: Midinfrared; SOI waveguides; Sub-wave length grating

Pure nickel fixed points for contact thermometry calibrations - Gotoh, M.; Todd, A. D. W. (International Journal of Thermophysics, 2014)
A robust fixed point using pure nickel contained in an alumina crucible has been developed for thermocouple calibrations. It was observed that a deep supercool often caused the freezing plateau to be short and have a large slope. A procedure for realizing the pure nickel fixed points was developed that reserved a small amount of nickel in the solid state to act as a seed for nucleation of the freeze. This procedure was found to allow freezing plateaus that were suitably long and flat to make them useful for calibrating thermocouples. Using a calibrated Pt/Pd thermocouple, the freezing temperature of nickel was determined to be (Formula presented.) with a (Formula presented.) uncertainty of (Formula presented.).
Keywords: Thermocouples; Fixed points; Pure nickels; Nickel

Inhibition of MMP-2 expression affects metabolic enzyme expression levels : proteomic analysis of rat cardiomyocytes - Lin, Han-Bin; Sharma, Keshav; Bialy, Dariusz; Wawrzynska, Magdalena; Purves, Randy; Cayabyab, Francisco S.; Wozniak, Mieczyslaw; Sawicki, Grzegorz (Journal of Proteomics, 2014)
In this study we examined the effect of inhibition of MMP-2 expression, using siRNA, on the cardiomyocyte proteome. Isolated cardiomyocytes were transfected with MMP-2 siRNA and incubated for 24. h. Control cardiomyocytes from the same heart were transfected with scrambled siRNA following the same protocol. Comparison of control cardiomyocyte proteomes with proteomes from MMP-2 suppressed cardiomyocytes revealed 13 protein spots of interest (9 protein spots increased; 4 decreased). Seven protein spots were identified as mitochondrial enzymes involved in energy production and represent: ATP synthase beta subunit, dihydrolipoyllysine-residue succinyltransferase component of 2-oxoglutarate dehydrogenase complex, cytochrome c oxidase subunit 5A, electron transfer flavoprotein subunit beta, NADH dehydrogenase (ubiquinone) 1 alpha subcomplex subunit 5 and a fragment of mitochondrial precursor of long-chain specific acyl-CoA dehydrogenase. Furthermore, precursor of heat shock protein 60 and Cu-Zn superoxide dismutase were identified. Two protein spots corresponding to MLC1 were also detected. In addition, ATP synthase activity was measured and was increased by approximately 30%.Together, these results indicate that MMP-2 inhibition represents a novel cardioprotective therapy by promoting alterations in the levels of mitochondrial enzymes for improved energy metabolism and by preventing degradation of contractile proteins needed for normal excitation-contraction coupling. Biological significance: During ischemia and reperfusion of cardiomyocytes, abnormality in excitation-contraction coupling and decreased energy metabolism often lead to myocardial infarction, but the cellular mechanisms are not fully elucidated. We show for the first time that intracellular inhibition of MMP-2 in cardiomyocytes increases contractility of aerobically perfused myocytes, which was accompanied by increased expression of contractile proteins (e.g., MLC-1). We also showed that MMP-2 inhibition produced a cardiomyocyte proteome that is consistent with improved mitochondrial energy metabolism (e.g., increased expression and activity of mitochondrial beta ATP synthase). Thus, MMP-2 appears to be involved in homeostatic regulation of protein turnover. Our results are significant since they point to targeting MMP-2 activity as a novel therapeutic option to limit myocardial damage by decreasing proteolytic degradation of mitochondrial metabolic enzymes and myocardial contractile proteins during ischemia. In addition, the development of novel pharmacological agents that selectively targets cardiac MMP-2 represents a novel approach to treat and prevent other heart diseases.
Keywords: Matrix metalloproteinase-2; ATP synthase; Cardiomyocytes; siRNA; Metabolic enzymes; Contractility

Plasticity in cell division patterns and auxin transport dependency during in vitro embryogenesis in Brassica napus - Soriano, Mercedes; Li, Hui; Jacquard, Cédric; Angenent, Gerco C.; Krochko, Joan; Offringa, Remko; Boutilier, Kim (Plant Cell, 2014)
In Arabidopsis thaliana, zygotic embryo divisions are highly regular, but it is not clear how embryo patterning is established in species or culture systems with irregular cell divisions. We investigated this using the Brassica napus microspore embryogenesis system, where the male gametophyte is reprogrammed in vitro to form haploid embryos in the absence of exogenous growth regulators. Microspore embryos are formed via two pathways: a zygotic-like pathway, characterized by initial suspensor formation followed by embryo proper formation from the distal cell of the suspensor, and a pathway characterized by initially unorganized embryos lacking a suspensor. Using embryo fate and auxin markers, we show that the zygotic-like pathway requires polar auxin transport for embryo proper specification from the suspensor, while the suspensorless pathway is polar auxin transport independent and marked by an initial auxin maximum, suggesting early embryo proper establishment in the absence of a basal suspensor. Polarity establishment in this suspensorless pathway was triggered and guided by rupture of the pollen exine. Irregular division patterns did not affect cell fate establishment in either pathway. These results confirm the importance of the suspensor and suspensor-driven auxin transport in patterning, but also uncover a mechanism where cell patterning is less regular and independent of auxin transport.

The measurement of the local acceleration of gravity for the NIST-4 watt balance - Newell, D. B.; Liard, J. O.; Chao, L. S.; Cao, A.; Seifert, F.; Haddad, D.; Pratt, J. R.; Schlamminger, S. (2014 Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014)
A new watt balance is being constructed at National Institute of Standards and Technology (NIST) in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. We describe the procedures used and give results for the measurements of the local acceleration of gravity in the new watt balance facility.
Keywords: Metric system; Fundamental constants; Planck constants; Watt balance; Gravitation

Advanced measurement and analysis of surface textures produced by micro-machining processes - Bordatchev, Evguieni V.; Hafiz, Abdullah M. K. (Measurement Science and Technology, 2014)
Surface texture of a part or a product has significant effects on its functionality, physical-mechanical properties and visual appearance. In particular for miniature products, the implication of surface quality becomes critical owing to the presence of geometrical features with micro/nano-scale dimensions. Qualitative and quantitative assessments of surface texture are carried out predominantly by profile parameters, which are often insufficient to address the contribution of constituent spatial components with varied amplitudes and wavelengths. In this context, this article presents a novel approach for advanced measurement and analysis of profile average roughness (Ra) and its spatial distribution at different wavelength intervals. The applicability of the proposed approach was verified for three different surface topographies prepared by grinding, laser micro-polishing and micro-milling processes. From the measurement and analysis results, Ra(λ) spatial distribution was found to be an effective measure of revealing the contributions of various spatial components within specific wavelength intervals towards formation of the entire surface profile. In addition, the approach was extended to the measurement and analysis of areal average roughness Sa(λ) spatial distribution within different wavelength intervals. Besides, the proposed method was demonstrated to be a useful technique in developing a functional correlation between a manufacturing process and its corresponding surface profile.
Keywords: profile and areal roughness; power spectral density function; spatial distribution; wavelength intervals; spatial components; surface texture

Microbial functional potential and community composition in permafrost-affected soils of the NW Canadian Arctic - Frank-Fahle, Beatrice A.; Yergeau, Etienne; Greer, Charles W.; Lantuit, Hugues; Wagner, Dirk (PLoS ONE, 2014)
Permafrost-affected soils are among the most obvious ecosystems in which current microbial controls on organic matter decomposition are changing as a result of global warming. Warmer conditions in polygonal tundra will lead to a deepening of the seasonal active layer, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. To identify current microbial assemblages in carbon rich, water saturated permafrost environments, four polygonal tundra sites were investigated on Herschel Island and the Yukon Coast, Western Canadian Arctic. Ion Torrent sequencing of bacterial and archaeal 16S rRNA amplicons revealed the presence of all major microbial soil groups and indicated a local, vertical heterogeneity of the polygonal tundra soil community with increasing depth. Microbial diversity was found to be highest in the surface layers, decreasing towards the permafrost table. Quantitative PCR analysis of functional genes involved in carbon and nitrogen-cycling revealed a high functional potential in the surface layers, decreasing with increasing active layer depth. We observed that soil properties driving microbial diversity and functional potential varied in each study site. These results highlight the small-scale heterogeneity of geomorphologically comparable sites, greatly restricting generalizations about the fate of permafrost-affected environments in a warming Arctic.
Keywords: carbon; nitrogen; RNA 16S; amplicon; Archean; arctic tundra; bacterial gene; Candida antarctica; carbon cycling; climate change; controlled study; environmental factor; gene function; gene identification; genetic heterogeneity; geographic distribution; microbial community; molecular dynamics; nitrogen cycling; permafrost; polymerase chain reaction; quantitative analysis; sequence analysis; soil analysis; species composition; species diversity; species richness; Arctic Regions; Cold Temperature; Polymerase Chain Reaction; Soil Microbiology

Linearity analysis of a calorimetric thermal voltage converter for RF-DC transfer difference up to 1 GHz - Shan, Yueyan; Meng, Yu Song; Filipski, Piotr S. (2014 Conference on Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014)
Linearity analysis of a calorimetric thermal voltage converter (CTVC) designed by the National Research Council of Canada for RF-DC transfer difference up to 1 GHz is presented in this paper. At higher frequencies, the CTVC is evaluated in terms of the calibration factor of a RF power sensor and the reflection coefficients at its Type-N connector. Good performance has been observed which indicates that CTVC could be a potential candidate for calibrating RF power sensors in terms of its RF-DC transfer difference.
Keywords: CTVC; Linearity; RF-DC transfer difference; Thermal voltage converters; Mathematical models

Subwavelength metastructures for dispersion engineering in planar waveguide devices - Halir, Robert; Ortega-Moñux, Alejandro; Cheben, Pavel; Maese-Novo, Alejandro; Pérez-Galacho, Diego; Alonso-Ramos, Carlos; Molina-Fernández, Íñigo; Wangüemert-Pérez, J. Gonzalo.; Schmid, Jens H.; Xu, Dan-Xia; Janz, Siegfried (SPIE - International Society for Optical Engineering. Proceedings, 2014)
High contrast structures with a sub-wavelength pitch, small enough to suppress diffraction, exhibit extraordinary optical properties: depending on the design they may behave as perfect mirrors, anti-reflective interfaces, homogenous materials with controllable refractive index, or strongly dispersive materials. Here we discuss on the design possibilities such structures offer in planar waveguide devices in silicon-on-insulator. We briefly review the application of sub-wavelength structures in a variety of waveguide devices. We then focus on some of the latest advances in the design ultra-compact and ultra-wideband multimode interference couplers based on dispersion engineered sub-wavelength structures.
Keywords: Directional couplers; Dispersion (waves); Indium phosphide; Interfaces (materials); Optical waveguides; Planar waveguides; Refractive index; Silicon on insulator technology; Waveguide components; Wavelength; Broadband device; Dispersion engineering; Multi-mode interference; Passive waveguides; Polarization splittings; Sub-wave length grating

Nitrogen-self-doped graphene-based non-precious metal catalyst with superior performance to Pt/C catalyst toward oxygen reduction reaction - He, Chunyong; Zhang, Jiu Jun; Shen, Pei Kang (Journal of Materials Chemistry A, 2014)
A new, simple and scalable synthesis methodology is invented for an N-self-doped graphene-based non-precious Fe catalyst (Fe-N-graphene) for the oxygen reduction reaction (ORR) both in acidic and alkaline media. The electrochemical characterization shows that this Fe-N-graphene catalyst possesses outstanding electrocatalytic ORR activity (similar to Pt/C catalyst in alkaline media and slightly lower in acidic media), and both superior stability and fuel (methanol and CO) tolerance to Pt/C catalysts. We believe that this is the first time for a non-precious metal catalyst to have superior ORR performance to Pt/C catalyst. In addition, our synthesis methodology can be scaled up for the mass production of N-self-doped graphene-based fuel cell non-noble metal catalysts and other nanomaterials.
Keywords: Electrocatalytic; Electrochemical characterizations; Mass production; Non-noble metal catalysts; Non-precious metal catalysts; Oxygen reduction reaction; Scalable synthesis; Synthesis methodology; Electrolytic reduction; Graphene; Platinum alloys; Precious metals; Synthesis (chemical); Catalysts

Gravimetry for watt balance measurements - Liard, J. O.; Sanchez, C. A.; Wood, B. M.; Inglis, A. D.; Silliker, R. J. (Metrologia, 2014)
In a watt balance (WB) the gravity on a known mass is used in the determination of the value of the Planck constant with a precision of <2 × 10-41 J s. To attain this precision the gravity value at the centre of a mass within the WB must be known with a relative uncertainty of <1 × 10-8. This necessitates laboratory gravity mapping in three dimensions, the establishment close to the WB of a gravity reference station, and modelling of the ties to the centre-of-mass location. The self-gravity of the WB must be accounted for, and since WB measurements run over several weeks, corrections for tidal, polar motion and atmospheric effects must be included. We describe the gravimetry carried out at the National Research Council of Canada WB laboratory, and include a discussion of past gravity variations in the vicinity of the WB, which suggest that seasonal variation may be of sufficient magnitude to affect results obtained with the balance.
Keywords: Gravimeters; Gravimetric analysis; Atmospheric effects; Planck constants; Reference stations; Relative uncertainty; Seasonal variation; Three dimensions; Watt balance; Gravitation

Fragmentation of massive dense cores down to ≲ 1000 AU : relation between fragmentation and density structure - Palau, Aina; Estalella, Robert; Girart, Josep M.; Fuente, Asuncion; Fontani, Francesco; Commerçon, Benoit; Busquet, Gemma; Bontemps, Sylvain; Sánchez-Monge, Álvaro; Zapata, Luis A.; Zhang, Qizhou; Hennebelle, Patrick; et al. (The Astrophysical Journal, 2014)
In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.
Keywords: galaxies: star clusters: general; radio continuum: ISM; stars: formation; techniques: high angular resolution

Sulfur refines MoO2 distribution enabling improved lithium ion battery performance - Xu, Zhanwei; Wang, Huanlei; Li, Zhi; Kohandehghan, Alireza; Ding, Jia; Chen, Jian; Cui, Kai; Mitlin, David (The Journal of Physical Chemistry C, 2014)
We employ a sulfur-assisted decomposition process to create agglomerates of large (200-500 nm) yet highly nanoporous three-dimensional MoO2 single crystals partially covered with a few atomic layers of MoS2 ("MoS2/MoO2 nanonetworks"). These materials are highly promising as lithium ion battery anodes. At a current density of 100 mA g-1, the MoS2/MoO2 nanonetworks exhibit a reversible discharge specific capacity of 1233 mAh g-1, with only 5% degradation after 80 full charge/discharge cycles. Moreover at the relatively fast discharging rates of 200 and 500 mA g-1, the capacities are 1158 and 826 mAh g-1, respectively. A comparison with literature shows that these are among the more promising reversible capacity, cycling capacity, and rate capability values reported for MoO2. The electrochemical properties are attributed to the material's nanoporous crystal morphology that allows for facile reversible transport of Li ions without either disintegration or agglomeration of the structure.
Keywords: Agglomeration; Lithium batteries; Sulfur; Charge/discharge cycle; Decomposition process; Discharge specific capacity; Lithium-ion battery; Lithium-ion battery anodes; Nanoporous crystals; Rate capabilities; Reversible capacity; Molybdenum oxide

On a persistent large discrepancy in some parameters of the spiral arms in the Milky Way - a statistical and modelling analysis - Vallee, Jacques P. (Monthly Notices of the Royal Astronomical Society, 2014)
Although the average over time of the arm parameters (arm shape, pitch angle, number of arms, interarm separation) shows constant values, this work investigates why some arm parameters (number of arms, pitch angle) have large discrepancies that are not decreasing with time, despite more and better observational data.Using statistics, we find several instances of poor or no comparisons with a four-arm galactic structure.Using modelling, we confirm that a two-arm galactic structure and a small pitch angle predict too many unseen spiral arm tangents.

Hexamethylcyclopentadiene : time-resolved photoelectron spectroscopy and ab initio multiple spawning simulations - Wolf, T. J. A.; Kuhlman, T. S.; Schalk, O.; Martínez, T. J.; Møller, K. B.; Stolow, A.; Unterreiner, A. -N. (Physical Chemistry Chemical Physics, 2014)
Progress in our understanding of ultrafast light-induced processes in molecules is best achieved through a close combination of experimental and theoretical approaches. Direct comparison is obtained if theory is able to directly reproduce experimental observables. Here, we present a joint approach comparing time-resolved photoelectron spectroscopy (TRPES) with ab initio multiple spawning (AIMS) simulations on the MS-MR-CASPT2 level of theory. We disentangle the relationship between two phenomena that dominate the immediate molecular response upon light absorption: a spectrally dependent delay of the photoelectron signal and an induction time prior to excited state depopulation in dynamics simulations. As a benchmark molecule, we have chosen hexamethylcyclopentadiene, which shows an unprecedentedly large spectral delay of (310 ± 20) fs in TRPES experiments. For the dynamics simulations, methyl groups were replaced by "hydrogen atoms" having mass 15 and TRPES spectra were calculated. These showed an induction time of (108 ± 10) fs which could directly be assigned to progress along a torsional mode leading to the intersection seam with the molecular ground state. In a stepladder-type approach, the close connection between the two phenomena could be elucidated, allowing for a comparison with other polyenes and supporting the general validity of this finding for their excited state dynamics. Thus, the combination of TRPES and AIMS proves to be a powerful tool for a thorough understanding of ultrafast excited state dynamics in polyenes.

Extreme conditions in a close analog to the young solar system : Herschel observations of ε Eridani - Greaves, J. S.; Sibthorpe, B.; Acke, B.; Pantin, E. E.; Vandenbussche, B.; Olofsson, G.; Dominik, C.; Barlow, M. J.; Bendo, G. J.; Blommaert, J. A. D. L.; Brandeker, A.; De Vries, B. L.; et al. (The Astrophysical Journal Letters, 2014)
Far-infrared Herschel images of the ε Eridani system, seen at a fifth of the Sun's present age, resolve two belts of debris emission. Fits to the 160 μm PACS image yield radial spans for these belts of 12-16 and 54-68 AU. The south end of the outer belt is ≈10% brighter than the north end in the PACS+SPIRE images at 160, 250, and 350 μm, indicating a pericenter glow attributable to a planet "c." From this asymmetry and an upper bound on the offset of the belt center, this second planet should be mildly eccentric (ec ≈ 0.03-0.3). Compared to the asteroid and Kuiper Belts of the young Sun, the ε Eri belts are intermediate in brightness and more similar to each other, with up to 20 km sized collisional fragments in the inner belt totaling ≈5% of an Earth mass. This reservoir may feed the hot dust close to the star and could send many impactors through the Habitable Zone, especially if it is being perturbed by the suspected planet ε Eri b, at semi-major axis ≈3 AU.
Keywords: circumstellar matter: planet–disk interactions; stars: individual (ε Eridani)

Photoluminescence fine structures in the fractional quantum Hall effect regime - Nomura, S.; Yamaguchi, M.; Tamura, H.; Akazaki, T.; Hirayama, Y.; Korkusinski, M.; Hawrylak, P. (Physical Review B - Condensed Matter and Materials Physics, 2014)
We investigate polarization-resolved fine structure in the photoluminescence (PL) in the fractional quantum Hall effect regime at B=4-6 T, where small Zeeman energy allows spin-depolarized ground states. We observe up to five distinct peaks with characteristic polarization and temperature dependence in the vicinity of =1/3 and quenching of the PL from triplet charged quasiexcitons at around =1/4. Those findings appear to be consistent with results of exact diagonalization on a Haldane sphere including all spin configurations and are understood to be PL from fractionally charged quasiexcitons.

In vivo 1H MRS of human gallbladder bile at 3 T in one and two dimensions: Detection and quantification of major biliary lipids - Mohajeri, Sanaz; Ijare, Omkar B.; Bezabeh, Tedros; King, Scott B.; Thomas, M. Albert; Minuk, Gerald; Lipschitz, Jeremy; Kirkpatrick, Iain; Smith, Mike; Smith, Ian C. P. (NMR in Biomedicine, 2014)
In vitro 1H MRS of human bile has shown potential in the diagnosis of various hepatopancreatobiliary (HPB) diseases. Previously, in vivo 1H MRS of human bile in gallbladder using a 1.5 T scanner demonstrated the possibility of quantification of choline-containing phospholipids (chol-PLs). However, other lipid components such as bile acids play an important role in the pathophysiology of the HPB system. We have employed a higher magnetic field strength (3 T), and a custom-built receive array coil, to improve the quality of in vivo 1H MRS of human bile in the gallbladder. We obtained significant improvement in the quality of 1D spectra (17 healthy volunteers) using a respiratory-gated PRESS sequence with well distinguished signals for total bile acids (TBAs) plus cholesterol resonating at 0.66 ppm, taurine-conjugated bile acids (TCBAs) at 3.08 ppm, chol-PLs at 3.22 ppm, glycineconjugated bile acids (GCBAs) at 3.74 ppm, and the amide proton (-NH) arising from GCBAs and TCBAs in the region 7.76-8.05 ppm. The peak areas of these signals were measured by deconvolution, and subsequently the molar concentrations of metabolites were estimated with good accuracy, except for that of TBAs plus cholesterol. The concentration of TBAs plus cholesterol was overestimated in some cases, which could be due to lipid contamination. In addition, we report the first 2D L-COSY spectra of human gallbladder bile in vivo (obtained in 15 healthy volunteers). 2D L-COSY spectra will be helpful in differentiating various biliary chol-PLs in pathological conditions of the HPB system.
Keywords: Bile acid; Detection and quantifications; Human bile; In-vivo; L-COSY; Two-dimension; Presses (machine tools); bile acid; bile acid conjugate; cholesterol; glycine; lipid; proton; taurine; taurine conjugated bile acid; bile; contamination; gallbladder; in vivo study; magnetic field; metabolite; proton nuclear magnetic resonance; respiratory gated imaging

Association between APOC1 polymorphism and alzheimer's disease: A case-control study and meta-analysis - Zhou, Qin; Zhao, Fan; Lv, Ze-ping; Zheng, Chen-guang; Zheng, Wei-dong; Sun, Liang; Wang, Na-na; Pang, Shenghang; De Andrade, Fabiana Michelsen; Fu, Mian; He, Xiang-hua; Hui, Juan; et al. (PLoS ONE, 2014)
Background: Previous association studies examining the relationship between the APOC1 polymorphism and susceptibility to Alzheimer's disease (AD) have shown conflicting results, and it is not clear if an APOC1 variant acts as a genetic risk factor in AD etiology across multiple populations. Methods: To confirm the risk association between APOC1 and AD, we designed a case-control study and also performed a meta-analysis of previously published studies. Results: Seventy-nine patients with AD and one hundred fifty-six unrelated controls were included in case-control study. No association was found between the variation of APOC1 and AD in stage 1 of our study. However, our meta-analysis pooled a total of 2092 AD patients and 2685 controls. The APOC1 rs11568822 polymorphism was associated with increased AD risk in Caucasians, Asians and Caribbean Hispanics, but not in African Americans. APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ2 = 119.46, OR = 2.79, 95% CI = 2.31-3.36, P<0.01). Conclusions: The APOC1 insertion allele, in combination with APOE ε4, likely serves as a potential risk factor for developing AD.
Keywords: apolipoprotein C1; apolipoprotein E4; African American; aged; allele; Alzheimer disease; APOC1 gene; Asian; Caribbean Hispanic; Caucasian; controlled study; disease association; disease classification; disease course; disease predisposition; DNA polymorphism; ethnic group; gene insertion; genetic risk; genetic variability; heterozygote; pathogenesis; protein function; Asian Continental Ancestry Group; Case-Control Studies; European Continental Ancestry Group; Gene Frequency; Genetic Predisposition to Disease; Genotype; Hispanic Americans; Linear Models; Polymorphism, Single Nucleotide; Risk Factors

Preliminary comparison of a 10 V programmable Josephson voltage standard and a hysteretic Josephson voltage standard - Granger, G.; Wood, B. M. (2014 Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014)
A 10 V programmable Josephson voltage standard system has been installed at the National Research Council Canada. The current margins for the first Josephson step at either current polarity are greater than 1 mA. A preliminary direct comparison of this programmable system with a hysteretic Josephson voltage standard is performed at 10 V.
Keywords: DC voltage; Josephson; Josephson voltage standards; Programmable Josephson voltage standard; System comparisons; Voltage measurement

A data driven approach for smart lighting - Guo, Hongyu (Harry); Letourneau, Sylvain; Yang, Chunsheng (Modern Advances in Applied Intelligence : 27th International Conference on Industrial Engineering and Other Applications of Applied Intelligent Systems, IEA/AIE 2014, Kaohsiung, Taiwan, June 3-6, 2014, Proceedings, Part II, 2014)
Smart lighting for commercial buildings should consider both the overall energy usage and the occupants' individual lighting preferences. This paper describes a study of using data mining techniques to attain this goal. The lighting application embraces the concept of Office Hotelling, where employees are not assigned permanent office spaces, but instead a temporary workplace is selected for each check-in staff. Specifically, taking check-in workers' light requirements as inputs, a collective classification strategy was deployed, aiming at simultaneously predicting the dimming levels of the shared luminaries in an open office sharing light. This classification information, together with the energy usages for possible office plans, provides us with lighting scenarios that can both meet users' lighting comfort and save energy consumption. We compare our approach with four other commonly used lighting control strategies. Our experimental study shows that the developed learning model can generate lighting policies that not only maximize the occupants' lighting satisfaction, but also substantially improve energy savings. Importantly, our data driven method is able to create an optimal lighting scenario with execution time that is suitable for a real-time responding system.
Keywords: Energy utilization; Intelligent systems; Office buildings; Classification informations; Collective classifications; Commercial building; Data-driven approach; Data-driven methods; Light requirements; Lighting applications; Lighting policies

Absolute rate constants for hydrogen atom transfer from tertiary amides to the cumyloxyl radical: evaluating the role of stereoelectronic effects - Salamone, Michela; Milan, Michela; Dilabio, Gino A.; Bietti, Massimo (Journal of Organic Chemistry, 2014)
A time-resolved kinetic study of the hydrogen atom transfer (HAT) reactions from a series of alkanamides to the cumyloxyl radical (CumO•) was carried out. With N,N-dialkylformamides HAT preferentially occurs from the formyl C-H bond, while in N-formylpyrrolidine HAT mostly occurs from the ring α-C-H bonds. With the acetamides and the alkanamides almost exclusive HAT from the C-H bonds that are α to nitrogen was observed. The results obtained show that alignment between the C-H bond being broken and the amide π-system can lead to significant increases in the HAT rate constant (k H). This finding points toward the important role of stereoelectronic effects on the HAT reactivity and selectivity. The highest kH values were measured for the reactions of CumO• with N-acylpyrrolidines. These substrates have ring α-C-H bonds that are held in a conformation that is optimally aligned with the amide π-system, thus allowing for the relatively facile HAT reaction. The lowest kH value was measured for the reaction of N,N-diisobutylacetamide, wherein the steric bulk associated with the N-isobutyl groups increases the energy barrier required to reach the most suitable conformation for HAT. The experimental results are well supported by the computed BDEs for the C-H bonds of the most representative substrates.
Keywords: Amides; Atoms; Hydrogen; Rate constants; C-H bond; Hydrogen atom transfers (HAT); Hydrogen-atom transfer; Steric bulk; Tertiary amides; Time-resolved kinetic study; Free radical reactions; acetamide derivative; acetonitrile; cumyloxyl radical; nitrogen; chemical bond; chemical procedures; chemical reaction; chemical structure; conformation; reaction analysis; stereochemistry; stereoelectronic effect

In situ controlled modification of the helium density in single helium-filled nanobubbles - David, M. -L.; Alix, K.; Pailloux, F.; Mauchamp, V.; Couillard, M.; Botton, G. A.; Pizzagalli, L. (Journal of Applied Physics, 2014)
We demonstrate that the helium density and corresponding pressure can be modified in single nano-scale bubbles embedded in semiconductors by using the electron beam of a scanning transmission electron microscope as a multifunctional probe: the measurement probe for imaging and chemical analysis and the irradiation source to modify concomitantly the pressure in a controllable way by fine tuning of the electron beam parameters. The control of the detrapping rate is achieved by varying the experimental conditions. The underlying physical mechanisms are discussed; our experimental observations suggest that the helium detrapping from bubbles could be interpreted in terms of direct ballistic collisions, leading to the ejection of the helium atoms from the bubble.
Keywords: Electron beams; Probes; Transmission electron microscopy; Ballistic collisions; Controlled modification; Electron-beam parameters; Experimental conditions; Irradiation sources; Multifunctional probes; Physical mechanism; Scanning transmission electron microscopes; Helium

Developing data-driven models to predict BEMS energy consumption for demand response systems - Yang, Chunsheng; Létourneau, Sylvain; Guo, Hongyu (Modern Advances in Applied Intelligence : 27th International Conference on Industrial Engineering and Other Applications of Applied Intelligent Systems, IEA/AIE 2014, Kaohsiung, Taiwan, June 3-6, 2014, Proceedings, Part I, 2014)
Energy consumption prediction for building energy management systems (BEMS) is one of the key factors in the success of energy saving measures in modern building operation, either residential buildings or commercial buildings. It provides a foundation for building owners to optimize not only the energy usage but also the operation to respond to the demand signals from smart grid. However, modeling energy consumption in traditional physic-modeling techniques remains a challenge. To address this issue, we present a data-mining-based methodology, as an alternative, for developing data-driven models to predict energy consumption for BEMSs. Following the methodology, we developed data-driven models for predicting energy consumption for a chiller in BEMS by using historic building operation data and weather forecast information. The models were evaluated with unseen data. The experimental results demonstrated that the data-driven models can predict energy consumption for chiller with promising accuracy.
Keywords: Cooling systems; Electric load forecasting; Intelligent systems; Learning algorithms; Learning systems; Models; Office buildings; Weather forecasting; Air handling units; Building energy management systems; Data-driven model; Demand response; Energy consumption prediction; Energy-saving measures; Forecast information; Residential building; Energy utilization

Integration of PMU, SCADA, AMI to accomplish expanded functional capabilities of Smart Grid - Mak, Sioe T.; So, Eddy (2014 Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014)
Technologies of synchrophasor systems - PMUs, control systems - SCADA, and smart meter systems - AMI are core enabling technologies for Smart Grid. The integration of these advanced sensor technologies to accomplish expanded functional capabilities of smart grid are discussed and presented.
Keywords: Smart meters; Advanced sensors; Functional capabilities; Smart grid; Synchrophasors; Integration

Electrochemical performance of solid sphere spinel LiMn2O 4 with high tap density synthesized by porous spherical Mn 3O4 - Guo, Donglei; Chang, Zhaorong; Tang, Hongwei; Li, Bao; Xu, Xinhong; Yuan, Xiao-Zi; Wang, Haijiang (Electrochimica Acta, 2014)
Solid sphere spinel LiMn2O4 materials are synthesized from porous spherical Mn3O4 particles with LiOH·H2O via a high temperature solid-phase reaction. Porous spherical Mn3O4 particles, composed of aggregated crystallites, can be obtained from as-prepared spherical β-MnOOH. The solid sphere spinel LiMn2O4 particles have a high tap-density of 2.67 g·cm-3 and are well-distributed with sizes ranging from 7-9 μm. The as-prepared β-MnOOH, Mn3O4 and LiMn2O4 are characterized by X-ray diffraction and scanning electron microscopy. As cathode materials, solid sphere spinel LiMn2O4, exhibits excellent cycling performance and rate capability for lithium-ion batteries. The initial discharge capacities are 127.1, 118.1, 106.3 and 87 mAh·g-1 at 0.2, 1, 5 and 10 C, respectively. At 5 C the discharge capacity retention rate can be maintained at 95% after 200 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy confirm the excellent electrochemical performances of the synthesized solid sphere spinel LiMn2O4 materials.
Keywords: Beta-hydroxy-manganese; High tap-density; Lithium manganese oxide; Solid spheres; Cathodes; Cyclic voltammetry; Electrochemical impedance spectroscopy; Lithium alloys; Lithium batteries; Lithium compounds; Manganese; Scanning electron microscopy; X ray diffraction; Spheres

A Herschel and BIMA study of the sequential star formation near the 48A HII region - Rygl, K. L. J.; Goedhart, S.; Polychroni, D.; Wyrowski, F.; Motte, F.; Elia, D.; Nguyen-Luong, Q.; Didelon, P.; Pestalozzi, M.; Benedettini, M.; Molinari, S.; André, P.; et al. (Monthly Notices of the Royal Astronomical Society, 2014)
We present the results of Herschel HOBYS (Herschel imaging survey of OB Young Stellar objects) photometricmapping combined with Berkeley Illinois Maryland Association (BIMA) observations and additional archival data, and perform an in-depth study of the evolutionary phases of the star-forming clumps in W 48A and their surroundings. Age estimates for the compact sources were derived from bolometric luminosities and envelope masses, which were obtained from the dust continuum emission, and agree within an order of magnitude with age estimates from molecular line and radio data. The clumps in W 48A are linearly aligned by age (east-old to west-young): we find a ultra-compact (UC) HII region, a young stellar object (YSO) with class II methanol maser emission, a YSO with a massive outflow and finally the NH2D prestellar cores from Pillai et al. This remarkable positioning reflects the (star) formation history of the region. We find that it is unlikely that the star formation in the W48A molecular cloud was triggered by the UC HII region and discuss the Aquila supershell expansion as a major influence on the evolution of W48A. We conclude that the combination of Herschel continuum data with interferometric molecular line and radio continuum data is important to derive trustworthy age estimates and interpret the origin of large-scale structures through kinematic information.
Keywords: star formation; ISM clouds; dust; extinction; Hii regions; ISM individual objects; W-48A; ISM molecules

Assignment of purity to primary metal calibrants using pin-cell VG 9000 glow discharge mass spectrometry : a primary method with direct traceability to the SI international system of units? - Sturgeon, R. E.; Methven, B.; Willie, S. N.; Grinberg, P. (Metrologia, 2014)
A measurement model based on the use of a pin-cell glow discharge source coupled to a VG 9000 sector field mass spectrometer (GD-MS) for the assignment of purity of high-purity metals, i.e., mass fraction of metal matrix, w(M), is presented. A mass balance approach to the calculation requires the determination and summation of impurity mass fractions of all extraneous elements present, including non-metals and gases. It is posited that a primary method of measurement can be devised to yield direct traceability of results to the SI. The major source of uncertainty in the traceability chain stems from the need to adjust the initially estimated quantity values of each impurity element by a relative sensitivity factor 'influence quantity' , derived from ab initio calculations, and validated through comparison with those derived through use of Certified Reference Materials. It is argued that the method is sufficiently well understood that a measurement equation can be formulated for which all parameters are measured in terms of SI units; that all contributions to uncertainty of measurement can be quantitatively evaluated, underpinning the metrological traceability; and that the performance of GD-MS in CCQM key and pilot comparisons of trace elements in complex metal matrices is in conformance with claimed capabilities. The applicability of the approach to metals in the 3N to 7N range of purity shows that fit-for-purpose relative expanded uncertainties of 0.5% to 0.000 05% can be conservatively achieved for w(M). Presentation of various instrument calibration scenarios vis-à-vis impact on SI traceability of results is also undertaken with a view to eliciting further discussion of this concept within the metrological community.
Keywords: glow discharge mass spectrometry; primary calibrants; high-purity metals; assignment of purity; traceability; primary method; Calibrants; Glow Discharge Mass Spectrometry

Surface plasmon resonance biomolecular recognition nanosystem : influence of the interfacial electrical potential - Lopatynskyi, Andrii; Guiver, Michael; Chegel, Volodymyr (Journal of Nanoscience and Nanotechnology, 2014)
It is shown that the response of a surface plasmon resonance nanosystem designed according to Kretschmann geometry on the application of an external electric potential to the gold-electrolyte interface is well described by the proposed mathematical model, which takes into account the geometric surface imperfection and dependence of optical constants of the surface layer of gold film and capacitance of the electrical double layer on applied voltage. This model allows the appropriate correction for results of electrochemical surface plasmon resonance measurements. The dependence of a value of biomolecules adsorption in a surface plasmon resonance nanosystem on applied electric potential is shown for the first time. It is found that a shift of surface plasmon resonance angular position (ΔθSPR) and a change of capacitance of electrical double layer on the surface of gold (Δ Cdl) for the adsorption of proteins under applied voltage are related to the nonlinear dependence ΔθSPR= (a+b ΔCdl)-1. This phenomenon can be exploited in biochemical analysis to monitor the interaction of biomolecules, enhance response of biosensors, block unwanted adsorption, etc.
Keywords: Surface plasmon resonance; Biomolecular adsorption; Biomolecular recognition; Electrical double layers; Electrical potential; Biosensors

The structure of CO2 hydrate between 0.7 and 1.0 GPa - Tulk, C. A.; Machida, S.; Klug, D. D.; Lu, H.; Guthrie, M.; Molaison, J. J. (Journal of Chemical Physics, 2014)
A deuterated sample of CO2 structure I (sI) clathrate hydrate (CO2 · 8.3 D2O) has been formed and neutron diffraction experiments up to 1.0 GPa at 240 K were performed. The sI CO2 hydrate transformed at 0.7 GPa into the high pressure phase that had been observed previously by Hirai et al. [J. Phys. Chem. 133, 124511 (2010)] and Bollengier et al. [Geochim. Cosmochim. Acta 119, 322 (2013)], but which had not been structurally identified. The current neutron diffraction data were successfully fitted to a filled ice structure with CO2 molecules filling the water channels. This CO2+water system has also been investigated using classical molecular dynamics and density functional ab initio methods to provide additional characterization of the high pressure structure. Both models indicate the water network adapts a MH-III "like" filled ice structure with considerable disorder of the orientations of the CO2 molecule. Furthermore, the disorder appears to be a direct result of the level of proton disorder in the water network. In contrast to the conclusions of Bollengier et al., our neutron diffraction data show that the filled ice phase can be recovered to ambient pressure (0.1MPa) at 96 K, and recrystallization to sI hydrate occurs upon subsequent heating to 150 K, possibly by first forming low density amorphous ice. Unlike other clathrate hydrate systems, which transform from the sI or sII structure to the hexagonal structure (sH) then to the filled ice structure, CO2 hydrate transforms directly from the sI form to the filled ice structure.

Rotating electrode methods and Oxygen reduction electrocatalysts : Preface - Xing, Wei; Yin, Geping; Zhang, Jiujun (Rotating Electrode Methods and Oxygen Reduction Electrocatalysts, 2014)

Applications of RDE and RRDE methods in oxygen reduction reaction - Du, Chungyu; Sun, Yongrong; Shen, Tiantian; Yin, Geping; Zhang, Jiujun (Rotating Electrode Methods and Oxygen Reduction Electrocatalysts, 2014)
This chapter reviews the applications of rotating disk electrode (RDE) and Rotating ring-disk electrode (RRDE) techniques in Oxygen reduction reaction (ORR) research and its associated catalyst evaluation. Some typical examples for RDE and RRDE analysis in obtaining the ORR kinetic information such as the overall electron-transfer number, electron-transfer coefficiency, and exchange current density are also given in this chapter. It demonstrates that both RDE and RRDE methods are the powerful tools in an ORR study, and using RDE and RRDE methods, ORR has been successfully studied on Pt electrode, carbon electrode, monolayer metal catalyst, Pt-based catalyst, and non-noble metal-based catalysts, respectively.
Keywords: ORR electrocatalysts; Oxygen reduction reaction (ORR); Rotating disk electrode (RDE); Rotating ring-disk electrode (RRDE)

Integrated air stream micromixer for performing bioanalytical assays on a plastic chip - Geissler, Matthias; Li, Kebin; Zhang, Xuefeng; Clime, Liviu; Robideau, Gregg P.; Bilodeau, Guillaume J.; Veres, Teodor (Lab on a Chip - Miniaturisation for Chemistry and Biology, 2014)
This paper describes the design, functioning and use of an integrated mixer that relies on air flux to agitate microliter entities of fluid in an embedded microfluidic cavity. The system was fabricated from multiple layers of a thermoplastic elastomer and features circuits for both liquid and air supply along with pneumatic valves for process control. Internally-dyed polymer particles have been used to visualize flow within the fluid phase during agitation. Numerical modelling of the micromixer revealed an overall efficacy of 10-1 to 10-2 for momentum transfer at the air-water interface. Simulation of air vortex dynamics showed dependency of the flow pattern on the velocity of the flux entering the cavity. Three bioanalytical assays have been performed as proof-of-concept demonstrations. In a first assay, cells of Listeria monocytogenes were combined with magnetic nanoparticles (NPs), resulting in high-density coverage of the bacteria's surface with NPs after 1 min of agitation. This finding is contrasted by a control experiment without agitation for which interaction between bacteria and NPs remains low. In a second one, capture and release of genomic DNA from fungi through adsorption onto magnetic beads was tested and shown to be improved by agitation compared to non-agitated controls. A third assay finally involved fluorescently-labelled target oligonucleotide strands and polystyrene particles modified with DNA capture probes to perform detection of nucleic acids on beads. Excellent selectivity was obtained in a competitive hybridization process using a multiplexed micromixer chip design.
Keywords: elastomer; genomic DNA; magnetic nanoparticle; plastic; polystyrene; adsorption; air stream micromixer; analytical equipment; comparative study; controlled study; hybridization; lab on a chip; liquid; Listeria monocytogenes; microfluidics; simulation; surface property; velocity; vortex motion

The Brassica oleracea genome reveals the asymmetrical evolution of polyploid genomes - Liu, Shengyi; Liu, Yumei; Yang, Xinhua; Tong, Chaobo; Edwards, David; Parkin, Isobel A. P.; Zhao, Meixia; Ma, Jianxin; Yu, Jingyin; Huang, Shunmou; Wang, Xiyin; Wang, Junyi; et al. (Nature Communications, 2014)
Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear. Brassica is an ideal model to increase knowledge of polyploid evolution. Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes. Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B. oleracea. This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus.
Keywords: alternative RNA splicing; article; Brassica oleracea; broccoli; cabbage; cauliflower; chromosome rearrangement; comparative study; evolution; gene expression; gene loss; gene sequence; genetic variability; genome; genomics; nonhuman; polyploidy; transposon

Use of night vision goggles for aerial forest fire detection - Tomkins, L.; Benzeroual, T.; Milner, A.; Zacher, J. E.; Ballagh, M.; McAlpine, R. S.; Doig, T.; Jennings, S.; Craig, G.; Allison, R. S. (International Journal of Wildland Fire, 2014)
Night-time flight searches using night vision goggles have the potential to improve early aerial detection of forest fires, which could in turn improve suppression effectiveness and reduce costs. Two sets of flight trials explored this potential in an operational context. With a clear line of sight, fires could be seen from many kilometres away (on average 3584m for controlled point sources and 6678m for real fires). Observers needed to be nearer to identify a light as a potential source worthy of further investigation. The average discrimination distance, at which a source could be confidently determined to be a fire or other bright light source, was 1193m (95% CI: 944 to 1442m). The hit rate was 68% over the course of the controlled experiment, higher than expectations based on the use of small fire sources and novice observers. The hit rate showed improvement over time, likely because of observers becoming familiar with the task and terrain. Night vision goggles enable sensitive detection of small fires, including those that were very difficult to detect during daytime patrols. The results demonstrate that small fires can be detected and reliably discriminated at night using night vision goggles at distances comparable to those recorded for daytime aerial detection patrols.

Antifreezes act as catalysts for methane hydrate formation from ice - McLaurin, Graham; Shin, Kyuchul; Alavi, Saman; Ripmeester, John A. (Angewandte Chemie - International Edition, 2014)
Contrary to the thermodynamic inhibiting effect of methanol on methane hydrate formation from aqueous phases, hydrate forms quickly at high yield by exposing frozen water-methanol mixtures with methanol concentrations ranging from 0.6-10 wt% to methane gas at pressures from 125 bars at 253 K. Formation rates are some two orders of magnitude greater than those obtained for samples without methanol and conversion of ice is essentially complete. Ammonia has a similar catalytic effect when used in concentrations of 0.3-2.7 wt%. The structure I methane hydrate formed in this manner was characterized by powder X-ray diffraction and Raman spectroscopy. Steps in the possible mechanism of action of methanol were studied with molecular dynamics simulations of the Ih (0001) basal plane exposed to methanol and methane gas. Simulations show that methanol from a surface aqueous layer slowly migrates into the ice lattice. Methane gas is preferentially adsorbed into the aqueous methanol surface layer. Possible consequences of the catalytic methane hydrate formation on hydrate plug formation in gas pipelines, on large scale energy-efficient gas hydrate formation, and in planetary science are discussed.
Keywords: Methanol; Molecular dynamics; Gas uptake; Methane hydrates; Powder X ray diffraction; Hydrates

Hepatitis C virus and microRNAs: MiRed in a host of possibilities - Singaravelu, Ragunath; Russell, Rodney S.; Tyrrell, D. Lorne; Pezacki, John Paul (Current Opinion in Virology, 2014)
It is well-established that the host microRNA (miRNA) milieu has a significant influence on the etiology of disease. In the context of viruses, such as hepatitis C virus (HCV), microRNAs have been shown to influence viral life cycles both directly, through interactions with the viral genome, and indirectly, through regulation of critical virus-associated host pathways. Several miRNA profiling studies have demonstrated that HCV infection aberrantly regulates a significant number of human miRNA. However, the biological relevance of these modulations remains poorly understood. In this review, we summarize recent research that has shed light on the pro-viral and anti-viral roles of HCV-induced changes in human miRNA expression and their significance in the development of HCV related sequelae and response to therapy.
Keywords: microRNA; biogenesis; disease association; disease course; hepatitis C; Hepatitis C virus; host pathogen interaction; life cycle; liver cell carcinoma; liver fibrosis; pathogenesis; regulatory mechanism; steatosis; virus genome; virus immunity

In vivo hyperspectral CARS and FWM microscopy of carotenoid accumulation in H. pluvialis - Slepkov, Aaron D.; Barlow, Aaron M.; Ridsdale, Andrew; McGinn, Patrick J.; Stolow, Albert (Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 2014)
Coherent anti-Stokes Raman scattering (CARS) and four-wave-mixing (FWM) microscopy are a related pair of powerful nonlinear optical characterization tools. These techniques often yield strong signals from concentrated samples, but because of their quadratic dependence on concentration, they are not typically employed for imaging or identifying dilute cellular constituents. We report here that, depending on the excitation wavelengths employed, both CARS and degenerate-FWM signals from carotenoid accumulations in alga cysts can be exceptionally large, allowing for low-power imaging of astaxanthin (AXN) deposits in Haematococcus pluvialis microalga. By use of a broadband laser pulse scheme for CARS and FWM, we are able to simultaneously collect strong intrinsic two-photon-excitation fluorescence signals from cellular chlorophyll in vivo. We show that CARS signals from astaxanthin (AXN) samples in vitro strictly follow the expected quadratic dependence on concentration, and we demonstrate the collection of wellresolved CARS spectra in the fingerprint region with sensitivity below 2mM. We suggest that multimodal nonlinear optical microscopy is sufficiently sensitive to AXN and chlorophyll concentrations that it will allow for non-invasive monitoring of carotenogenesis in live H. pluvialis microalgae.
Keywords: Astaxanthin; Carotenogenesis; Coherent anti-Stokes Raman scattering; Haematococcus pluvialis; Nonlinear optical microscopy; Algae; Chlorophyll; Fluorescence; Medical imaging; Optical data storage; Optical microscopy; Pigments; Raman scattering; Raman spectroscopy; Coherent scattering

Facile synthesis of LiAl0.1Mn1.9O4 as cathode material for lithium ion batteries : towards rate and cycling capabilities at an elevated temperature - Guo, Donglei; Li, Bao; Chang, Zhaorong; Tang, Hongwei; Xu, Xinhong; Chang, Kun; Shangguan, Enbao; Yuan, Xiao-Zi; Wang, Haijiang (Electrochimica Acta, 2014)
To improve the cycling performance of spinel LiMn2O4, Al-doped LiMn2O4, LiAl0.1Mn1.9O4, is synthesized using Mn1.9Al0.1O3 precursor and LiOH·H2O via a low temperature solid-phase reaction. The Mn1.9Al0.1O3 precursor, prepared from the electrolytic manganese dioxide (EMD) and Al(OH)3, is composed of spherical particles with an average diameter of 300 nm, and has a large interspace. Energy dispersive spectrometer (EDS) indicates the Al element is well distributed in Mn1.9Al0.1O3 and LiAl0.1Mn1.9O4. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images show that the LiAl0.1Mn1.9O4 sample has a high crystallinity with sizes ranging from 300 to 500 nm. Electrochemical properties of LiAl0.1Mn1.9O4 are studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge. The results show that LiAl0.1Mn1.9O4 possesses better rate and cycling capabilities than LiMn2O4 at both 25 °C and 55 °C. At a rate of 5 C, the capacity retention ratio of the LiMn1.9Al0.1O4 electrode after 100 cycles is about 95% at 25 °C and about 90% at 55 °C.
Keywords: Lithium-ion batteries; Al-doped lithium manganate; Elevated temperature property; Solid-phase reaction; Cathode materials

Ta and Nb co-doped TiO2 and its carbon-hybrid materials for supporting Pt-Pd alloy electrocatalysts for PEM fuel cell oxygen reduction reaction - Wang, Yan-Jie; Wilkinson, David P.; Neburchilov, Vladimir; Song, Chaojie; Guest, Alan; Zhang, Jiujun (Journal of Materials Chemistry A, 2014)
To explore possible substitutes for carbon supports in PEM fuel cell catalysts, both Ta and Nb co-doped TiO2 (TaNbTiO2) and carbon-TaNbTiO2 (C-TaNbTiO2) hybrid support materials are successfully synthesized by a modified thermal hydrolysis method. These materials are employed as support candidates for Pt-Pd alloy catalysts for the oxygen reduction reaction. Among several supported catalysts, 20 wt% Pt 0.62Pd0.38/C75wt%-(Ta0.01Nb 0.03Ti0.96O2)25wt% is found to have an oxygen reduction reaction (ORR) mass activity of 260 mA mgPt -1 and an ORR loss of 30%, which are slightly better than those of the commercially available Pt/C baseline catalyst which has a mass activity of 110 mA mgPt -1 and an ORR loss of 40% probably because of a strong physicochemical interaction among the Pt-Pd alloy catalyst particle, carbon-TaNbTiO2 support and carbon, as well as the stability of oxide to protect carbon from corrosion by the distribution of oxide onto carbon, respectively.
Keywords: Alloys; Carbon; Electrocatalysts; Electrolytic reduction; Hybrid materials; Niobium; Platinum; Proton exchange membrane fuel cells (PEMFC); Tantalum; Titanium dioxide; Carbon support; Co-doped tio; Hybrid support; Mass activity; Oxygen reduction reaction; PEM fuel cell; Physico-chemical interactions; Thermal hydrolysis; Platinum alloys

Minimizing RF performance spikes in a cryogenic orthomode transducer (OMT) - Henke, Doug; Claude, Stéphane (IEEE Transactions on Microwave Theory and Techniques, 2014)
The turnstile junction exhibits very low cross-polarization leakage and is suitable for low-noise millimeter-wave receivers. For use in a cryogenic receiver, it is best if the orthomode transducer (OMT) is implemented in waveguide, contains no additional assembly features, and may be directly machined. However, machined OMTs are prone to sharp signal drop-outs that are costly to overall performance since they show up directly as spikes in receiver noise. We explore the various factors contributing to this degradation and discuss how the current design mitigates each cause. Final performance is demonstrated at cryogenic temperatures.
Keywords: Cryogenics; Millimeter waves; Polarization; Radio astronomy; Signal receivers; Assembly features; Cryogenic temperatures; Low cross polarization; Millimeter-wave receivers; Ortho-mode transducers; Polarization splitters; Receiver noise; Turnstile junctions; Transducers

Next-generation sequencing of 16S ribosomal RNA gene amplicons - Sanschagrin, Sylvie; Yergeau, Étienne (Journal of Visualized Experiments, 2014)
One of the major questions in microbial ecology is "who is there?" This question can be answered using various tools, but one of the long-lasting gold standards is to sequence 16S ribosomal RNA (rRNA) gene amplicons generated by domain-level PCR reactions amplifying from genomic DNA. Traditionally, this was performed by cloning and Sanger (capillary electrophoresis) sequencing of PCR amplicons. The advent of next-generation sequencing has tremendously simplified and increased the sequencing depth for 16S rRNA gene sequencing. The introduction of benchtop sequencers now allows small labs to perform their 16S rRNA sequencing in-house in a matter of days. Here, an approach for 16S rRNA gene amplicon sequencing using a benchtop next-generation sequencer is detailed. The environmental DNA is first amplified by PCR using primers that contain sequencing adapters and barcodes. They are then coupled to spherical particles via emulsion PCR. The particles are loaded on a disposable chip and the chip is inserted in the sequencing machine after which the sequencing is performed. The sequences are retrieved in fastq format, filtered and the barcodes are used to establish the sample membership of the reads. The filtered and binned reads are then further analyzed using publically available tools. An example analysis where the reads were classified with a taxonomy-finding algorithm within the software package Mothur is given. The method outlined here is simple, inexpensive and straightforward and should help smaller labs to take advantage from the ongoing genomic revolution.
Keywords: Molecular Biology; Issue 90; Metagenomics; Bacteria; 16S ribosomal RNA gene; Amplicon sequencing; Next-generation sequencing; benchtop sequencers

Bacterial community structure and soil properties of a subarctic tundra soil in Council, Alaska - Kim, Hye Min; Jung, Ji Young; Yergeau, Etienne; Hwang, Chung Yeon; Hinzman, Larry; Nam, Sungjin; Hong, Soon Gyu; Kim, Ok-Sun; Chun, Jongsik; Lee, Yoo Kyung (FEMS Microbiology Ecology, 2014)
The subarctic region is highly responsive and vulnerable to climate change. Understanding the structure of subarctic soil microbial communities is essential for predicting the response of the subarctic soil environment to climate change. To determine the composition of the bacterial community and its relationship with soil properties, we investigated the bacterial community structure and properties of surface soil from the moist acidic tussock tundra in Council, Alaska. We collected 70 soil samples with 25-m intervals between sampling points from 0-10 cm to 10-20 cm depths. The bacterial community was analyzed by pyrosequencing of 16S rRNA genes, and the following soil properties were analyzed: soil moisture content (MC), pH, total carbon (TC), total nitrogen (TN), and inorganic nitrogen (NH4+ and NO3-). The community compositions of the two different depths showed that Alphaproteobacteria decreased with soil depth. Among the soil properties measured, soil pH was the most significant factor correlating with bacterial community in both upper and lower-layer soils. Bacterial community similarity based on jackknifed unweighted unifrac distance showed greater similarity across horizontal layers than through the vertical depth. This study showed that soil depth and pH were the most important soil properties determining bacterial community structure of the subarctic tundra soil in Council, Alaska.
Keywords: bacterial RNA; carbon; nitrogen; RNA 16S; Actinobacteria; biomass; DNA sequence; genetics; microbiology; molecular genetics; molecular typing; pH; phylogeny; pyrosequencing; soil; soil microflora; tussock tundra; Alaska; soil bacteria; soil depth; Hydrogen-Ion Concentration; Molecular Sequence Data; Proteobacteria; RNA, Bacterial; Sequence Analysis, DNA; Soil Microbiology

Disk-loss and disk-renewal phases in classical be stars. II. Contrasting with stable and variable disks - Draper, Zachary H.; Wisniewski, John P.; Bjorkman, Karen S.; Meade, Marilyn R.; Haubois, Xavier; Mota, Bruno C.; Carciofi, Alex C.; Bjorkman, Jon E. (The Astrophysical Journal, 2014)
Recent observational and theoretical studies of classical Be stars have established the utility of polarization color diagrams (PCDs) in helping to constrain the time-dependent mass decretion rates of these systems. We expand on our pilot observational study of this phenomenon, and report the detailed analysis of a long-term (1989-2004) spectropolarimetric survey of nine additional classical Be stars, including systems exhibiting evidence of partial disk-loss/disk-growth episodes as well as systems exhibiting long-term stable disks. After carefully characterizing and removing the interstellar polarization along the line of sight to each of these targets, we analyze their intrinsic polarization behavior. We find that many steady-state Be disks pause at the top of the PCD, as predicted by theory. We also observe sharp declines in the Balmer jump polarization for later spectral type, near edge-on steady-state disks, again as recently predicted by theory, likely caused when the base density of the disk is very high, and the outer region of the edge-on disk starts to self absorb a significant number of Balmer jump photons. The intrinsic V-band polarization and polarization position angle of γ Cas exhibits variations that seem to phase with the orbital period of a known one-armed density structure in this disk, similar to the theoretical predictions of Halonen & Jones. We also observe stochastic jumps in the intrinsic polarization across the Balmer jump of several known Be+sdO systems, and speculate that the thermal inflation of part of the outer region of these disks could be responsible for producing this observational phenomenon. Finally, we estimate the base densities of this sample of stars to be between ≈8 × 10-11 and ≈4 × 10-12gcm-3 during quasi steady state periods given there maximum observed polarization.
Keywords: circumstellar matter; stars: individual (pi Aquarii, 60 Cygni, 48 Librae, psi Persei, phi Persei, 28 Cygni, 66 Ophiuchi, gamma Casseopia, omega Orionis, FY CMa, 59 Cyg)

Functional characterization of xanthoxin dehydrogenase in rice - Endo, Akira; Nelson, Ken M.; Thoms, Ken; Abrams, Suzanne R.; Nambara, Eiji; Sato, Yutaka (Journal of Plant Physiology, 2014)
Abscisic acid (ABA) is a phytohormone that plays a key role in biotic and abiotic stress responses. ABA metabolic genes are promising targets for molecular breeding work to improve stress tolerance in crops. The accumulation of ABA does not always improve stress tolerance since stress-induced accumulation of ABA in pollen inhibits the normal course of gametogenesis, affecting grain yields in cereals. This effect highlights the importance of manipulating the ABA levels according to the type of tissues. The aim of this study was to assign an ABA biosynthetic enzyme, xanthoxin dehydrogenase (XanDH), as a functional marker to modulate ABA levels in rice. XanDH is a member of the short-chain dehydrogenase/reductase family that catalyzes the conversion of xanthoxin to abscisyl aldehyde (ABAld). Previously, this enzyme had only been identified in Arabidopsis, as AtABA2. In this study, a XanDH named OsABA2 was identified in rice. Phylogenetic analysis indicated that a single gene encodes for OsABA2 in the rice genome. Its amino acid sequence contains two motifs that are essential for cofactor binding and catalytic activity. Expression analysis of OsABA2 mRNA showed that the transcript level did not change in response to treatment with ABA or dehydration. Recombinant OsABA2 protein expressed in Escherichia coli converted xanthoxin to ABAld in an NAD-dependent manner. Moreover, expression of OsABA2 in an Arabidopsis aba2 mutant rescued the aba2 mutant phenotypes, characterized by reduced growth, increased water loss, and germination in the presence of paclobutrazol, a gibberellin biosynthesis inhibitor or high concentration of glucose. These results indicate that OsABA2 is a rice XanDH that functions in ABA biosynthesis.
Keywords: Abscisic acid biosynthesis; Oryza sativa; Short-chain dehydrogenase/reductase; Xanthoxin dehydrogenase

Optical society of America's 2013 topical meeting on optical interference coatings: Introduction by the feature editors - Tilsch, Markus; Ristau, Detlev; Li, Li; Piegari, Angela (Applied Optics, 2014)
This Applied Optics feature issue is dedicated to the 12th topical meeting on Optical Interference Coatings held on 16-21 June 2013 in Whistler, British Columbia, Canada. The conference, taking place in a three-year rotation with conferences in Europe and Asia, is a focal point for global technical interchange in the field of optical interference coatings and provides premier opportunities for people in the field to present their new advances in research and development. Papers presented at the conference cover a broad range of topics, from thin film deposition processes, designs and modeling, materials, and metrologies to a wide array of thin film applications.
Keywords: Optical interference coatings; Optical Society of America

Toward a new vaccine for pertussis - Robbins, J.B.; Schneerson, R.; Kubler-Kielb, J.; Keith, J.M.; Trollfors, B.; Vinogradov, E.; Shiloach, J. (Proceedings of the National Academy of Sciences of the United States of America, 2014)
To overcome the limitations of the current pertussis vaccines, those of limited duration of action and failure to induce direct killing of Bordetella pertussis, a synthetic scheme was devised for preparing a conjugate vaccine composed of the Bordetella bronchiseptica core oligosaccharide with one terminal trisaccharide to aminooxylated BSA via their terminal ketodeoxyoctanate residues. Conjugate-induced antibodies, by a fraction of an estimated human dose injected into young outbred mice as a saline solution, were bactericidal against B. pertussis, and their titers correlated with their ELISA values. The carrier protein is planned to be genetically altered pertussis toxoid. Such conjugates are easy to prepare, stable, and should add both to the level and duration of immunity induced by current vaccine-induced pertussis antibodies and reduce the circulation of B. pertussis.
Keywords: bacterium antibody; carrier protein; neutralizing antibody; oligosaccharide; pertussis vaccine; trisaccharide; antibacterial activity; Bordetella bronchiseptica; Bordetella parapertussis; Bordetella pertussis; conjugate; human; nonhuman; pertussis; priority journal; review; lipooligosaccharide conjugate; new pertussis vaccine; Animals; Antibodies, Bacterial; Bacterial Vaccines; Bordetella bronchiseptica; Bordetella pertussis; Drug Design; Enzyme-Linked Immunosorbent Assay; Humans; Mice; Oligosaccharides; Serum Albumin, Bovine; Vaccines, Conjugate; Whooping Cough; lipooligosaccharide conjugate; new pertussis vaccine

Electrocatalysts and catalyst layers for oxygen reduction reaction - Feng, Ligang; Sun, Xiujuan; Yao, Shikui; Liu, Changpeng; Xing, Wei; Zhang, Jiujun (Rotating Electrode Methods and Oxygen Reduction Electrocatalysts, 2014)
In this chapter, to give some basic knowledge and concepts, some fundamentals about the catalyst activity and stability of oxygen reduction reaction (ORR) electrocatalysts, which are the targeted research systems by rotating electrode methods, are presented. A detailed description about the electrocatalysts and catalyst layers and their applications for ORR in terms of their types, structures, properties, catalytic activity/stability, as well as their research progress in the past several decades are also given. Furthermore, both the synthesis and characterization methods for ORR electrocatalysts, and the fabrication procedures for catalyst layers are also reviewed.
Keywords: Electrocatalytic theory; Oxygen reduction reaction (ORR); ORR catalyst layer; Rotating disk electrode (RDE); Rotating ring-disk electrode (RRDE); electrocatalysts>

The role of roughness-induced damping in the oscillatory motion of bilayer graphene - Ye, Zhijiang; Otero de la Roza, Alberto; Johnson, Erin R.; Martini, Ashlie (Nanotechnology, 2014)
A multi-scale theoretical model is presented that is the first to offer quantitative agreement with experimental measurements of self-retraction and oscillation of bilayer graphene. The model integrates density-functional theory calculations of the energetics driving flake retraction and molecular-dynamics simulations capturing the dynamic response of laterally-offset rough surfaces. We demonstrate that nanoscale roughness explains self-retraction motion and propose a recipe for tuning that motion by controlling friction.
Keywords: Graphene; Bilayer Graphene; Molecular dynamics simulations; Oscillatory motion; Density functional theory

Solution-processed annealing-free ZnO nanoparticles for stable inverted organic solar cells - Alem, Salima; Lu, Jianping; Movileanu, Raluca; Kololuoma, Terho; Dadvand, Afshin; Tao, Ye (Organic Electronics: physics, materials, applications, 2014)
We report the development and application of high-quality zinc oxide nanoparticles (ZnO NPs) processed in air for stable inverted bulk heterojunction solar cells as an electron extraction layer (EEL). The ZnO NPs (average size ∼11 nm) were dispersed in chloroform and stabilized by propylamine (PA). We demonstrated that the ZnO NP dispersion with 4 vol.% of PA as stabilizer can be used in air directly and remains clear up to one month after preparation. Our inverted solar cells consisted of a blade-coated poly(N-9′-heptadecanyl-2, 7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′, 3′-benzothiadiazole (PCDTBT) and [6,6]-phenyl C71-butyric acid methyl ester (PC71BM) (1: 4 by weight) active layer sandwiched between a ZnO electron extraction layer and a MoO3/Ag anode. All solar cells with ZnO films fabricated in air using PA-stabilized ZnO dispersions prepared within a time window of one month exhibited power conversion efficiencies (PCE) above 4%. In contrast, if the ZnO film was prepared in air using regular un-stabilized ZnO NP dispersion, the PCE would drop to 0.2% due to poor film quality. More interestingly, X-ray photoelectron spectroscopy and nuclear magnetic resonance measurements indicated that the PA ligands were not covalently bonded to ZnO NPs and did not exist in the deposited ZnO films. The spin-cast ZnO thin films (without any thermal treatment) are insoluble in organic solvents and can be directly used as an EEL in solar cells. This feature is beneficial for fabricating organic solar cells on flexible polymer substrates. More importantly, our non-encapsulated inverted solar cells are highly stable with their PCEs remaining unchanged after being stored in air for 50 days.
Keywords: Convergence of numerical methods; Extraction; Heterojunctions; Metallic films; Molybdenum oxide; Nanoparticles; Photoelectrons; X ray photoelectron spectroscopy; Zinc oxide; Bulk heterojunction; Inverted solar cells; Power conversion efficiencies; Propylamines; Zinc oxide nanoparticles; Solar cells

Biogeochemical activity of microbial biofilms in the water column overlying uranium mine tailings - Bondici, V. F.; Khan, N. H.; Swerhone, G. D. W.; Dynes, J. J.; Lawrence, J. R.; Yergeau, E.; Wolfaardt, G. M.; Warner, J.; Korber, D. R. (Journal of Applied Microbiology, 2014)
Aims: To describe microbial diversity, biofilm composition and biogeochemical potential within biofilms in the water overlying uranium tailings characterized by high pH, high metal concentration and low permeability. Methods and Results: To estimate microbial diversity in biofilms formed in water columns overlying uranium mine tailings, culture-dependent and culture-independent methods were employed. High-throughput sequencing revealed the presence of 11 phyla; however, the majority of the sequences were affiliated with four major lineages (Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes) as confirmed by culture-based methods. Dominant phylotypes were closely related to methylotrophs (Methylobacterium) and bacterial groups able to utilize complex hydrocarbons (Aquabacterium and Dechloromonas). Microbial diversity in biofilms from the 13 m depth was significantly different that in biofilms from 1 to 41 m (P < 0·05). Phylotypes closely related to iron-reducing bacteria were identified at each depth; whereas sulphate-, thio-sulphate-, sulphite- and sulphur-reducing bacteria, at low abundance, were only detected at lower depths. Confocal scanning laser microscopy (CSLM) was used to investigate polymer quantity and composition of the biofilm components, and principal component analysis of the CLSM data revealed that the relative abundance of α-L-fucose and N-acetyl-glucosamine/lipopolysaccharide residues separated tailings-water interface biofilms from those from other depths. Reduced (ferrous) iron was detected within all the biofilm samples examined by scanning X-ray transmission microscopy. Conclusions: Microbial communities within the water column covering a highly alkaline uranium tailings body form biofilms with microenvironments where iron reduction takes place. Significance and Impact of the Study: This study demonstrates the biogeochemical potential of microbial biofilm communities in the water column covering an alkaline uranium tailings body; specifically, the nature of the bacterial groups detected (Aquabacterium, Dechloromonas) and the presence of reduced iron suggest that complex hydrocarbons are available for bacterial growth and geochemical change, such as iron reduction, can occur even though the system bulk phase is predominantly oxic.

Application of isothermal titration calorimetry for characterizing thermodynamic parameters of biomolecular interactions : peptide self-assembly and protein adsorption case studies - Kabiri, Maryam; Unsworth, Larry D. (Biomacromolecules, 2014)
The complex nature of macromolecular interactions usually makes it very hard to identify the molecular-level mechanisms that ultimately dictate the result of these interactions. This is especially evident in the case of biological systems, where the complex interaction of molecules in various situations may be responsible for driving biomolecular interactions themselves but also has a broader effect at the cell and/or tissue level. This review will endeavor to further the understanding of biomolecular interactions utilizing the isothermal titration calorimetry (ITC) technique for thermodynamic characterization of two extremely important biomaterial systems, viz., peptide self-assembly and nonfouling polymer-modified surfaces. The advantages and shortcomings of this technique will be presented along with a thorough review of the recent application of ITC to these two areas. Furthermore, the controversies associated with the enthalpy-entropy compensation effect as well as thermodynamic equilibrium state for such interactions will be discussed.
Keywords: Biomolecular interactions; Isothermal titration calorimetry; Peptide self assemblies; Protein adsorption; Thermodynamic parameter; peptide; polymer; protein; adiabaticity; adsorption; Article; case study; enthalpy; entropy; equilibrium constant; human; isothermal titration calorimetry; macromolecule; molecular interaction; protein analysis; surface plasmon resonance; theory; thermodynamics

Infrared spectra of He-, Ne-, and Ar-C6D6 - George, J.; McKellar, A. R. W.; Moazzen-Ahmadi, N. (Chemical Physics Letters, 2014)
Spectra of He-, Ne- and Ar-C6D6 in the region of the ν12 fundamental of C6D6 are observed in a pulsed supersonic jet expansion using a tunable optical parametric oscillator laser source. These are the first reported infrared spectra of rare gas-benzene complexes and the first observation in any region for He- and Ne-C 6D6. Two bands are studied for each complex: the ν12 fundamental itself (≈2289 cm-1) and the ν2 + ν13 combination band (≈2276 cm-1) which are coupled by a Fermi resonance. Effective intermolecular separations of 3.593(1) and 3.455(1) Å are obtained for He- and Ne-C6D 6, respectively, consistent with previous ultraviolet and microwave results for the analogous C6H6 complexes.
Keywords: Optical parametric oscillators; Spectroscopy; Supersonic aerodynamics; Combination bands; Fermi resonances; Infrared spectrum; Intermolecular separations; Laser sources; Pulsed supersonic jet expansions; Two bands; Argon lasers

Determination of relative ion chamber calibration coefficients from depth-ionization measurements in clinical electron beams - Muir, B. R.; McEwen, M. R.; Rogers, D. W. O. (Physics in Medicine and Biology, 2014)
A method is presented to obtain ion chamber calibration coefficients relative to secondary standard reference chambers in electron beams using depth-ionization measurements. Results are obtained as a function of depth and average electron energy at depth in 4, 8, 12 and 18 MeV electron beams from the NRC Elekta Precise linac. The PTW Roos, Scanditronix NACP-02, PTW Advanced Markus and NE 2571 ion chambers are investigated. The challenges and limitations of the method are discussed. The proposed method produces useful data at shallow depths. At depths past the reference depth, small shifts in positioning or drifts in the incident beam energy affect the results, thereby providing a built-in test of incident electron energy drifts and/or chamber set-up. Polarity corrections for ion chambers as a function of average electron energy at depth agree with literature data. The proposed method produces results consistent with those obtained using the conventional calibration procedure while gaining much more information about the behavior of the ion chamber with similar data acquisition time. Measurement uncertainties in calibration coefficients obtained with this method are estimated to be less than 0.5%. These results open up the possibility of using depth-ionization measurements to yield chamber ratios which may be suitable for primary standards-level dissemination.
Keywords: Calibration coefficients; Clinical electron beams; Reference dosimetry; Electron beams

Nanowire waveguides launching single photons in a Gaussian mode for ideal fiber coupling - Bulgarini, Gabriele; Reimer, Michael E.; Bouwes Bavinck, Maaike; Jöns, Klaus D.; Dalacu, Dan; Poole, Philip J.; Bakkers, Erik P. A. M.; Zwiller, Val (Nano Letters, 2014)
Quantum communication as well as integrated photonic circuits require single photons propagating in a well-defined Gaussian mode. However, tailoring the emission mode to a Gaussian remains an unsolved challenge for solid-state quantum emitters due to their random positioning in the host material or photonic structure. Here, we overcome these limitations by embedding a semiconductor quantum dot in a tapered nanowire waveguide. Owing to the deterministic positioning of the emitter in the waveguide, we demonstrate a Gaussian emission profile in the far field. Hence, we further couple the emission into a single-mode optical fiber with a record efficiency of 93%, thereby addressing a major hurdle for practical implementation of single photon sources in emerging photonic technologies.
Keywords: Quantum dot; nanowire; single photon emission; waveguide modes; Fourier microscopy

Facile fabrication of LiMn2O4 microspheres from multi-shell MnO2 for high-performance lithium-ion batteries - Li, Bao; Wei, Xiurge; Chang, Zhaorong; Chen, Xenian; Yuan, Xiao-Zi; Wang, Haijiang (Materials Letters, 2014)
A facile and convenient method is proposed to fabricate the LiMn 2O4 microspheres from multi-shell MnO2. Comparing to the LiMn2O4 synthesized from commercial electrolytic MnO2 (EMD), the LiMn2O4 microspheres synthesized in this work exhibit a close-to-theory specific capacity of 145.9 mA h/g at 0.2 C, while the LiMn2O4 from commercial MnO2 only shows a value of 105.3 mA h/g under the same testing conditions. LiMn2O4 microspheres also exhibit an excellent rate performance: 131.8 and 113.3 mA h/g at 5 and 10 C, respectively. This facile and convenient method to prepare LiMn2O4 microspheres provides a new way to fabricate lithium manganate cathode materials with high specific capacity and rate performance.
Keywords: Energy storage and conversions; LiMn2O4; Nanocomposites; Multi-shell MnO2; Lithium-ion battery

Using gas modifiers to significantly improve sensitivity and selectivity in a cylindrical FAIMS device - Purves, Randy W.; Ozog, Allison R.; Ambrose, Stephen J.; Prasad, Satendra; Belford, Michael; Dunyach, Jean-Jacques (Journal of the American Society for Mass Spectrometry, 2014)
(Graph Presented) Recent reports describing enhanced performance when using gas additives in a DMS device (planar electrodes) have indicated that comparable benefits are not attainable using FAIMS (cylindrical electrodes), owing to the non-homogeneous electric fields within the analyzer region. In this study, a FAIMS system (having cylindrical electrodes) was modified to allow for controlled delivery of gas additives. An experiment was carried out that illustrates the important distinction between gas modifiers present as unregulated contaminants and modifiers added in a controlled manner. The effect of contamination was simulated by adjusting the ESI needle position to promote incomplete desolvation, thereby permitting ESI solvent vapor into the FAIMS analyzer region, causing signal instability and irreproducible CV values. However, by actively controlling the delivery of the gas modifier, reproducible CV spectra were obtained. The effects of adding different gas modifiers were examined using 15 positive ions having mass-to-charge (m/z) values between 90 and 734. Significant improvements in peak capacity and increases in ion transmission were readily attained by adding acetonitrile vapor, even at trace levels (≤0.1%). Increases in signal intensity were greatest for the low m/z ions; for the six lowest molecular weight species, signal intensities increased by ∼10- to over 100-fold compared with using nitrogen without gas additives, resulting in equivalent or better signal intensities compared with ESI without FAIMS. These results confirm that analytical benefits derived from the addition of gas modifiers reported with a uniform electric field (DMS) also are observed using a non-homogenous electric field (FAIMS) in the analyser region.
Keywords: DMS; Electrospray; FAIMS; Gas additives; Gas-phase separation

Practical approaches to determine ventilation rate for offices while considering physical and chemical variables for building material emissions - Ye, Wei; Won, Doyun; Zhang, Xu (Building and Environment, 2014)
Indoor air pollutants in offices can be attributed to various sources, including building materials, consumer products, and exhalation from occupants. The required ventilation rate for offices can be determined by estimating the majority of emissions originated from building materials, as an additional determinant factor for ventilation rate, with the assumption of constant ventilation with 100% outdoor air, uniform indoor mixing, and no chemical reactions. In this paper, the validity of these assumptions was investigated by incorporating the effects of various physical and chemical factors in determining material emissions and ventilation rates. Three physical factors investigated were recirculation ventilation, intermittent ventilation and pollutant distribution. Simplified methods using correction factors were proposed to revise the ventilation rate and validated by emission modeling and CFD method. In addition, three chemical factors were discussed. First, 28 building materials were selected from the NRC database and each was subject to determining the ventilation rate. As a result, 28 leading pollutants that are likely to determine the ventilation rate were obtained. Because most of the leading pollutants are reactants rather than products of indoor air reactions, it was concluded that the current ventilation rate determining methods should still be applicable. Additionally, a correction method was proposed for a reaction product such as formaldehyde. Second, the methods to revise ventilation rate based on temperature variation and pollutant concentration in outdoor air were proposed. This study showed that ventilation rate for offices could be determined based on building material emissions in more realistic ventilation and environmental conditions.
Keywords: Volatile organic compounds; Recirculation; Intermittent; Distribution; Reaction; Health-relevant pollutant

Molecule-surface recognition between heterocyclic aromatic compounds and kaolinite in toluene investigated by molecular theory of solvation and thermodynamic and kinetic experiments - Huang, WenJuan; Dedzo, Gustave Kenne; Stoyanov, Stanislav R.; Lyubimova, Olga; Gusarov, Sergey; Singh, Shashank; Lao, Hayes; Kovalenko, Andriy; Detellier, Christian (The Journal of Physical Chemistry C, 2014)
Molecular recognition interactions between kaolinite and a series of heterocyclic aromatic compounds (HAC) representative of the N- and S-containing moieties in petroleum asphaltene macromolecules are investigated using the three-dimensional reference interaction site model with the Kovalenko-Hirata closure approximation (3D-RISM-KH) theory of solvation and experimental techniques in toluene solvent. The statistical-mechanical 3D-RISM-KH molecular theory of solvation predicts the adsorption configuration and thermodynamics from the 3D site density distribution functions and total solvation free energy, respectively, for adsorption of HAC and toluene on kaolinite. Spectrophotometric measurements show that, among the HAC studied, only acridine and phenanthridine adsorb quantitatively on kaolinite. For these pyridinic HAC, the adsorption results fitted to the Langmuir isotherm in the monolayer domain suggest a uniform monolayer of HAC molecules. The 3D-RISM-KH studies predict that the aluminum hydroxide surface of kaolinite is preferred for HAC adsorption due to strong hydrogen bonding with the pyridinic N atoms, while the rest of the HAC adsorb weaker. Adsorption on the silicon oxide side is weak and delocalized, as evident from the 3D solvation free energy density. Toluene sites effectively compete with non-hydrogen bonding HAC, such as fused thiophenes, for the kaolinite surface. The adsorption enthalpy and phenanthridine-acridine loading ratio are calculated and correlated with the experimentally determined Langmuir constant and adsorption loading. This combined experimental and computational modeling approach is aimed to provide insight into the specific interactions among clays, bitumen, and solvents so as to help accelerate the development of environmentally friendly and efficient desorption systems for nonaqueous extraction of bitumen from Oil Sands, an important unconventional petroleum reserve.
Keywords: Heterocyclic aromatic compounds; Kinetic experiment; Molecular theory of solvation; Molecule surface

γ Pegasi: testing Vega-like magnetic fields in B stars - Neiner, C.; Monin, D.; Leroy, B.; Mathis, S.; Bohlender, D. (Astronomy and Astrophysics, 2014)
Context. The bright B pulsator γ Peg shows both p and g modes of β Cep and SPB types. It has also been claimed that it is a magnetic star, while others do not detect any magnetic field. Aims. We check for the presence of a magnetic field, with the aim to characterise it if it exists, or else provide a firm upper limit of its strength if it is not detected. If γ Peg is magnetic as claimed, it would make an ideal asteroseismic target for testing various theoretical scenarios. If it is very weakly magnetic, it would be the first observation of an extension of Vega-like fields to early B stars. Finally, if it is not magnetic and we can provide a very low upper limit on its non-detected field, it would make an important result for stellar evolution models. Methods. We acquired high resolution, high signal-to-noise spectropolarimetric Narval data at Telescope Bernard Lyot (TBL). We also gathered existing dimaPol spectropolarimetric data from the Dominion Astrophysical Observatory (DAO) and Musicos spectropolarimetric data from TBL. We analysed the Narval and Musicos observations using the least-squares deconvolution (LSD) technique to derive the longitudinal magnetic field and Zeeman signatures in lines. The longitudinal field strength was also extracted from the Hβ line observed with the DAO. With a Monte Carlo simulation we derived the maximum strength of the field possibly hosted by γ Peg. Results. We find that no magnetic signatures are visible in the very high quality spectropolarimetric data. The average longitudinal field measured in the Narval data is Bl = -0.1 ± 0.4 G. We derive a very strict upper limit of the dipolar field strength of Bpol ~ 40 G. Conclusions. We conclude that γ Peg is not magnetic: it hosts neither a strong stable fossil field as observed in a fraction of massive stars nor a very weak Vega-like field. There is therefore no evidence that Vega-like fields exist in B stars, contrary to the predictions by fossil field dichotomy scenarios. These scenarios should thus be revised. Our results also provide strong constraints for stellar evolution models.
Keywords: Astrophysical observatory; Longitudinal fields; Longitudinal magnetic fields; Magnetic signatures; Stars: early-type; Stars: individual; Stars: magnetic field; Stellar evolutions; Magnetic fields; Monte Carlo methods; Stars

Sampling current ratio bridge for calibration of current transducers up to 10 kA with 5 ppm uncertainty - van den Brom, Helko E.; Rietveld, Gert; So, Eddy (2014 Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014)
A sampling current ratio bridge has been developed, tested and validated for the accurate complex ratio measurement of AC current transducers for primary currents up to 10 kA with expanded uncertainties of 5 · 10-6 in magnitude and 5 μrad in phase (k = 2). A unique property of the system is the use of digitizers for sampling of the secondary current signals and step-down transformers with a large number of current ratios. This allows for the accurate calibration of a large variety of different current transformers and other types of current transducers.
Keywords: Electric instrument transformers; Sampling; Current ratios; Current transducer; uncertainty; Electric current measurement

Atom-scale surface reactivity mediated by long-ranged equilibrium charge transfer - Piva, Paul G.; Dilabio, Gino A.; Livadaru, Lucian; Wolkow, Robert A. (Physical Review B - Condensed Matter and Materials Physics, 2014)
The observation of reaction outcomes at the bulk scale provides an average view of chemical processes, obscuring potentially significant differences in the behavior of matter at the atom scale. Through a series of atom-resolved scanning tunneling microscopy experiments, the inhomogeneous reactivity of silicon surface dangling bond states is revealed. The differences in reactivity provide evidence for the coexistence of neutral and negative surface states on these surfaces. It is shown that reactivity can be modulated through the density of surface states and by the bulk dopant level. These findings demonstrate that site-specific surface reactivity at the atom scale can be modulated by nonlocal charge allocation and provide opportunities for controlling chemistry at this scale.

What will it take to observe processes in 'real time'? - Leone, Stephen R.; Mccurdy, C. William; Burgdörfer, Joachim; Cederbaum, Lorenz S.; Chang, Zenghu; Dudovich, Nirit; Feist, Johannes; Greene, Chris H.; Ivanov, Misha; Kienberger, Reinhard; Keller, Ursula; Kling, Matthias F.; et al. (Nature Photonics, 2014)

An ode to the atomic weights - Meija, Juris (Nature Chemistry, 2014)

Atmospheric methane oxidizers are present and active in Canadian high Arctic soils - Martineau, Christine; Pan, Yao; Bodrossy, Levente; Yergeau, Etienne; Whyte, Lyle G.; Greer, Charles W. (FEMS Microbiology Ecology, 2014)
The melting of permafrost and the associated potential for methane emissions to the atmosphere are major concerns in the context of global warming. However, soils can also represent a significant sink for methane through the activity of methane-oxidizing bacteria (MOB). In this study, we looked at the activity, diversity, and community structure of MOB at two sampling depths within the active layer in three soils from the Canadian high Arctic. These soils had the capacity to oxidize methane at low (15 ppm) and high (1000 ppm) methane concentrations, but rates differed greatly depending on the sampling date, depth, and site. The pmoA gene sequences related to two genotypes of uncultured MOB involved in atmospheric methane oxidation, the 'upland soil cluster gamma' and the 'upland soil cluster alpha', were detected in soils with near neutral and acidic pH, respectively. Other groups of MOB, including Type I methanotrophs and the 'Cluster 1' genotype, were also detected, indicating a broader diversity of MOB than previously reported for Arctic soils. Overall, the results reported here showed that methane oxidation at both low and high methane concentrations occurs in high Arctic soils and revealed that different groups of atmospheric MOB inhabit these soils. Methane oxidation at both low and high methane concentrations occurs in high Arctic soils and different groups of methane-oxidizing bacteria inhabit these soils.
Keywords: Bacteria (microorganisms); Methylococcaceae; bacterial protein; methane; methane monooxygenase; oxygenase; particulate methane monooxygenase; RNA 16S; bacterial gene; DNA sequence; enzymology; genetic variability; genetics; metabolism; microbiology; molecular genetics; nucleotide sequence; oxidation reduction reaction; phylogeny; pmoA microarray; uncultured methanotrophs; High-affinity methane oxidation; microbial ecology in cold environments; Arctic Regions; Genes, Bacterial; Genetic Variation; Molecular Sequence Data; Oxidation-Reduction; Sequence Analysis, DNA; Soil Microbiology

High-precision quadruple isotope dilution method for simultaneous determination of nitrite and nitrate in seawater by GCMS after derivatization with triethyloxonium tetrafluoroborate - Pagliano, E.; Meija, J.; Mester, Z. (Analytica Chimica Acta, 2014)
Quadruple isotope dilution mass spectrometry (ID4MS) has been applied for simultaneous determination of nitrite and nitrate in seawater. ID4MS allows high-precision measurements and entails the use of isotopic internal standards (18O-nitrite and 15N-nitrate). We include a tutorial on ID4MS outlining optimal experimental design which generates results with low uncertainties and obviates the need for direct (separate) evaluation of the procedural blank. Nitrite and nitrate detection was achieved using a headspace GCMS procedure based on single-step aqueous derivatization with triethyloxonium tetrafluoroborate at room temperature. In this paper the sample preparation was revised and fundamental aspects of this chemistry are presented. The proposed method has detection limits in the low parts-per-billion for both analytes, is reliable, precise, and has been validated using a seawater certified reference material (MOOS-2). Simplicity of the experimental design, low detection limits, and the use of quadruple isotope dilution makes the present method superior to the state-of-the-art for determination of nitrite and nitrate, and an ideal candidate for reference measurements of these analytes in seawater. © 2014.
Keywords: Quadruple isotope dilution; High-precision; Nitrite and nitrate; Seawater; Triethyloxonium tetrafluoroborate derivatization; GCMS

Binary orbits as the driver of γ-ray emission and mass ejection in classical novae - Chomiuk, Laura; Linford, Justin D.; Yang, Jun; O'Brien, T. J.; Paragi, Zsolt; Mioduszewski, Amy J.; Beswick, R. J.; Cheung, C. C.; Mukai, Koji; Nelson, Thomas; Ribeiro, Valerio A. R. M.; Rupen, Michael P.; et al. (Nature, 2014)
Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10-4 solarmasses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection innovae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds or binary interaction with the nova envelope. Classical novae are now routinely detected at gigaelectronvolt γ-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the γ-rayemitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion. At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of γ-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are γ-ray emitters.
Keywords: astrophysics; explosion; velocity; wavelength; X-ray spectroscopy; acceleration; Article; gamma radiation; image analysis; motion; optical resolution; spectrum; synchrotron radiation; wind

Tunneling splitting in double-proton transfer: Direct diagonalization results for porphycene - Smedarchina, Zorka; Siebrand, Willem; Fernández-Ramos, Antonio (Journal of Chemical Physics, 2014)
Zero-point and excited level splittings due to double-proton tunneling are calculated for porphycene and the results are compared with experiment. The calculation makes use of a multidimensional imaginary-mode Hamiltonian, diagonalized directly by an effective reduction of its dimensionality. Porphycene has a complex potential energy surface with nine stationary configurations that allow a variety of tunneling paths, many of which include classically accessible regions. A symmetry-based approach is used to show that the zero-point level, although located above the cis minimum, corresponds to concerted tunneling along a direct trans - trans path; a corresponding cis - cis path is predicted at higher energy. This supports the conclusion of a previous paper [Z. Smedarchina, W. Siebrand, and A. Fernández-Ramos, J. Chem. Phys. 127, 174513 (2007)] based on the instanton approach to a model Hamiltonian of correlated double-proton transfer. A multidimensional tunneling Hamiltonian is then generated, based on a double-minimum potential along the coordinate of concerted proton motion, which is newly evaluated at the RI-CC2/cc-pVTZ level of theory. To make it suitable for diagonalization, its dimensionality is reduced by treating fast weakly coupled modes in the adiabatic approximation. This results in a coordinate-dependent mass of tunneling, which is included in a unique Hermitian form into the kinetic energy operator. The reduced Hamiltonian contains three symmetric and one antisymmetric mode coupled to the tunneling mode and is diagonalized by a modified Jacobi-Davidson algorithm implemented in the Jadamilu software for sparse matrices. The results are in satisfactory agreement with the observed splitting of the zero-point level and several vibrational fundamentals after a partial reassignment, imposed by recently derived selection rules. They also agree well with instanton calculations based on the same Hamiltonian.
Keywords: Diagonalizations; Porphycene; Tunneling splittings

Microscopic theory of the optical properties of colloidal graphene quantum dots - Ozfidan, Isil; Korkusinski, Marek; Güçlü, A. Devrim; McGuire, John A.; Hawrylak, Pawel (Physical Review B - Condensed Matter and Materials Physics, 2014)
We present a microscopic theory of electronic and optical properties of colloidal graphene quantum dots (CGQDs). The single-particle properties are described in the tight-binding model based on the pz carbon orbitals. Electron-electron screened Coulomb direct, exchange, and scattering matrix elements are calculated using Slater pz orbitals. The many-body ground state and excited states are constructed as a linear combination of a finite number of excitations from the Hartree-Fock (HF) ground state (GS) by exact diagonalization techniques. HF ground states corresponding to semiconductor, Mott-insulator, and spin-polarized phases are obtained as a function of the strength of the screened interaction versus the tunneling matrix element. In the semiconducting phase of a triangular CGQD, the top of the valence band and the bottom of the conduction band are found to be degenerate due to rotational symmetry. The singlet and triplet exciton spectra from the HF GS are obtained by solving the Bethe-Salpeter equation. The low-energy exciton spectrum is predicted to consist of two bright-singlet exciton states corresponding to two circular polarizations of light and a lower-energy band of two dark singlets and 12 dark triplets. The robustness of the bright degenerate singlet pair against correlations in the many-body state is demonstrated as well as the breaking of the degeneracy by the lowering of symmetry of the CGQD. The band-gap renormalization, electron-hole attraction, fine structure, oscillator strength, and polarization of the exciton are analyzed as a function of the size, shape, screening, and symmetry of the CGQD. The theoretical results are compared with experimental absorption spectra.

Recent advances in electrochemical detection of arsenic in drinking and ground waters - Luong, John H. T.; Lam, Edmond; Male, Keith B. (Analytical Methods, 2014)
Anodic stripping voltammetry (ASV) using noble electrodes is based on the reduction of As3+ to As0, followed by its stripping or oxidation to As3+ or As5+ species, the two predominant forms of arsenic in water. The rapid and convenient ASV method can detect As(iii) at the low ppb level, but it is susceptible to interferences from various endogenous metals or organic compounds in waters. Electrode surface modification with metallic nanoparticles (NPs), carbonaceous nanomaterials (carbon nanotubes and graphene) and even enzymes (arsenite oxidase) can improve detection sensitivity and selectivity, while circumventing such interferences. All electrochemical methods aim for a detection limit below the World Health Organization guideline value of 10 ppb (133.3 nM). Despite numerous publications in this field during the last ten years with respect to novel electrode materials and electrolytes, reproducibility of electrochemical detection is still problematic and the analysis of arsenic in real ground-water samples is far from certainty and triviality. Considerable efforts are still needed to develop electrode materials and analytical procedures for reliable detection of arsenic with sub-ppb levels in the presence of endogenous toxic metals and organics in water matrices.
Keywords: Electrodes; Groundwater; Voltammetry; Analytical procedure; Anodic stripping voltammetry; Detection sensitivity; ELectrochemical detection; ELectrochemical methods; Electrode surface modifications; Metallic nanoparticles; World Health Organization; Arsenic

The ALMA assembly, integration, and verification project: A retrospective analysis - Lopez, B.; Knee, L. B. G.; Jager, H.; Whyborn, N.; McMullin, J.; Murowinski, R.; Peck, A.; Corder, S. (SPIE - International Society for Optical Engineering. Proceedings, 2014)
The Atacama Large Millimeter/submillimeter Array (ALMA) is a joint project between astronomical organizations in Europe, North America, and East Asia, in collaboration with the Republic of Chile. ALMA consists of 54 twelve-meter antennas and 12 seven-meter antennas operating as an aperture synthesis array in the (sub)millimeter wavelength range. Assembly, Integration, and Verification (AIV) of the antennas was completed at the end of the year 2013, while the final optimization and complete expansion to validate all planned observing modes will continue. This paper compares the actually obtained results of the period 2008-2013 with the baselines that had been laid out in the early project-planning phase (2005-2007). First plans made for ALMA AIV had already established a two-phased project life-cycle: phase 1 for setting up necessary infrastructure and common facilities, and taking the first three antennas to the start of commissioning; and phase 2 focused on the steady state processing of the remaining units. Throughout the execution of the project this lifecycle was refined and two additional phases were added, namely a transition phase between phases 1 and 2, and a closing phase to address the project ramp-down. A sub-project called Accelerated Commissioning and Science Verification (ACSV) was carried out during the year 2009 in order to provide focus to the whole ALMA organization, and to accomplish the start-of-commissioning milestone. Early phases of CSV focused on validating the basic performance and calibration. Over time additional observing modes have been validated as capabilities expanded both in hardware and software. This retrospective analysis describes the originally presented project staffing plans and schedules, the underlying assumptions, identified risks and operational models, among others. For comparison actual data on staffing levels, the resultant schedule, additional risks identified and those that actually materialized, are presented. The observed similarities and differences are then analyzed and explained, and corresponding lessons learned are presented.
Keywords: Antennas; Astronomy; Life cycle; Personnel selection; Plant shutdowns; Project management; Risk perception; Systems engineering; Aperture synthesis; Atacama Large Millimeter/sub-millimeter Array (ALMA); Hardware and software; Joint projects; Millimeter wavelength; Operational model; Retrospective analysis; Transition phase; Risk assessment

Coordinate swapping in standard addition graphs for analytical chemistry : a simplified path for uncertainty calculation in linear and nonlinear plots - Meija, Juris; Pagliano, Enea; Mester, Zoltán (Analytical Chemistry, 2014)
Uncertainty of the result from the method of standard addition is often underestimated due to neglect of the covariance between the intercept and the slope. In order to simplify the data analysis from standard addition experiments, we propose x-y coordinate swapping in conventional linear regression. Unlike the ratio of the intercept and slope, which is the result of the traditional method of standard addition, the result of the inverse standard addition is obtained directly from the intercept of the swapped calibration line. Consequently, the uncertainty evaluation becomes markedly simpler. The method is also applicable to nonlinear curves, such as the quadratic model, without incurring any additional complexity.
Keywords: Chemical analysis; Calibration lines; Nonlinear curves; Quadratic modeling; Standard addition; Uncertainty calculations; Uncertainty evaluation; Chemistry

Oxidation resistance of novel multilayer coatings for gas turbine components - Gao, F.; Yang, Q.; Liu, R.; Huang, X. (Surface Engineering, 2014)
This article presents a study of the oxidation behaviour of two multilayer coatings, denoted as MC I and MC II, respectively, which are designed with a three-layer architecture: a Cr-Si barrier layer on the IN738 substrate, a NiCrAlY intermediate layer, and an aluminised top layer. The emphasis of this research is on the total amount of oxide scales formed and the residual oxide scales on the coatings with various combinations among the three layers to investigate the effects of each layer and the interactions between the layers on the oxidation resistance of the coatings. The difference between the two multilayer coatings is that the Al content in the top layer of MC II is twice as much as that in the top layer of MC I. The coatings are fabricated through a combination of plasma spray and pack cementation processes, and then experience oxidation test at 1050 °C for 1000 h. The average thicknesses of the oxide scales are around 15 and 45 μm for MC I and MC II, respectively. The experimental results are modelled using the analysis of variance. Two models for the volume of total oxide scales and the ratio of the volume of spalled oxide scales to the volume of total oxide scales, are proposed to study the effects of the coating layers on the formation and spallation of oxide scales, which directly affect the oxidation resistance of the coatings. The experimental and analytical results demonstrate that the Cr-Si layer and its interactions with the other coating layers affect the spallation of oxide scales the most among the three layers. It prevents Al and Cr from diffusing into the substrate. The interaction between the Cr-Si layer and the NiCrAlY layer, and the increase in Al/Ni ratio of the aluminide top layer, promote the formation of oxide scales and also minimise the spallation of oxide scales.
Keywords: Aluminised layer; Cr-Si layer; Multi-layer-coating; Multi-layered coatings; NiCrAlY; Oxidation

Stearoyl-CoA desaturase inhibition blocks formation of hepatitis C virus-induced specialized membranes - Lyn, Rodney K.; Singaravelu, Ragunath; Kargman, Stacia; O'Hara, Shifawn; Chan, Helen; Oballa, Renata; Huang, Zheng; Jones, Daniel M.; Ridsdale, Andrew; Russell, Rodney S.; Partridge, Anthony W.; Pezacki, John P. (Scientific Reports, 2014)
Hepatitis C virus (HCV) replication is dependent on the formation of specialized membrane structures; however, the host factor requirements for the formation of these HCV complexes remain unclear. Herein, we demonstrate that inhibition of stearoyl-CoA desaturase 1 (SCD-1) halts the biosynthesis of unsaturated fatty acids, such as oleic acid, and negatively modulates HCV replication. Unsaturated fatty acids play key roles in membrane curvature and fluidity. Mechanistically, we demonstrate that SCD-1 inhibition disrupts the integrity of membranous HCV replication complexes and renders HCV RNA susceptible to nuclease-mediated degradation. Our work establishes a novel function for unsaturated fatty acids in HCV replication.

Asymmetry in the noise equivalent angle performance of the JWST fine guidance sensor - Rowlands, Neil; Warner, Gerry; Albert, Loic; Hardy, Tim; Pipher, Judith; Hutchings, John; Doyon, Rene (SPIE - International Society for Optical Engineering. Proceedings, 2014)
The James Webb Space Telescope Fine Guidance Sensor makes use of three 2048×2048 five micron cutoff H2RG HgCdTe detectors from Teledyne Imaging Systems. The FGS consists of two Guider channels and a Near-InfraRed Imager and Slitless Spectrograph (NIRISS) channel. We report here on detailed tests results from the Guider channels originating in both instrument level performance testing and from recent Guider performance testing with the FGS integrated into JWST's Integrated Science Instrument Module (ISIM). A key performance parameter is the noise equivalent angle (NEA) or centroiding precision. The JWST requirement flowed down to the Guiders is a NEA of 4 milli-arcseonds, equivalent to approximately 1/20th of a detector pixel. This performance has been achieved in the testing to date. We have noted a systematic asymmetry in the NEA depending on whether the NEA in the row or column direction is considered. This asymmetry depends on guide star brightness and reaches its maximum, where the row NEA is 15% to 20% larger than the column NEA, at the dim end of the Guide star brightness range. We evaluate the detector level characteristics of spatially correlated noise and asymmetric inter-pixel capacitance (IPC) as potential sources of this NEA asymmetry. Modelling is used to estimate the impact on NEA of these potential contributors. These model results are then compared to the Guider test results obtained to date in an effort to isolate the cause of this effect. While asymmetric IPC can induce asymmetric NEA, the required magnitude of IPC is far greater than observed in these detectors. Thus, spatially correlated noise was found to be the most likely cause of the asymmetric NEA.
Keywords: Infrared detectors; Instrument testing; Space telescopes; Stars; FGS; Guidance sensors; H2RG; HgCdTe; JWST; SIDECAR; Luminance

Quantitative radio-labeled biomolecule detection using a functionalized CMOS sensor - Griffin, R. H.; Mozenson, O.; Beking, M. A.; Derosa, M. C.; Lopinski, Gregory (Greg); Tarr, N. G. (IEEE Transactions on Nuclear Science, 2014)
For the first time, a CMOS imager has been used to detect the presence of radio-labeled target biomolecules captured on a functionalized surface. A CMOS image sensor from an SLR camera was used. Using aptamer functionalization the system successfully detected 32P labeled adenosine triphosphate (ATP) at concentrations well below those typically associated with fluorescence-based sensor architectures. The system has also demonstrated its amenability to multiplexed/spotted biomolecule detection. GEANT4, a Monte Carlo toolkit for simulating the passage of radiation through matter, was used to analyze the detector. Radiolabel detection offers the potential for direct quantitative measurement of bound biomolecules which is advantageous compared to the use of fluorescent tags.
Keywords: Adenosinetriphosphate; CMOS integrated circuits; Detectors; Fluorescence; Radioactive tracers; Aptamers; Biomolecule detection; CMOS imagers; Geant4; Radiolabel; Biomolecules

Recommending a value for the Newtonian gravitational constant - Wood, Barry M. (Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2014)
The primary objective of the CODATA Task Group on Fundamental Constants is 'to periodically provide the scientific and technological communities with a self-consistent set of internationally recommended values of the basic constants and conversion factors of physics and chemistry based on all of the relevant data available at a given point in time'. I discuss why the availability of these recommended values is important and how it simplifies and improves science. I outline the process of determining the recommended values and introduce the principles that are used to deal with discrepant results. In particular, I discuss the specific challenges posed by the present situation of gravitational constant experimental results and how these principles were applied to the most recent 2010 recommended value. Finally, I speculate about what may be expected for the next recommended value of the gravitational constant scheduled for evaluation in 2014.
Keywords: Fundamental constants; Gravitational constant; Least-squares adjustment; Newtonians

Interfacing a tetraphenylethene derivative and a smart hydrogel for temperature-dependent photoluminescence with sensitive thermoresponse - Jiang, Yingnan; Yang, Xudong; Ma, Cheng; Wang, Chuanxi; Chen, Yang; Dong, Fengxia; Yang, Bai; Yu, Kui; Lin, Quan (ACS Applied Materials and Interfaces, 2014)
We report, for the first time, the design and synthesis of thermoresponsive (TR) photoluminescent (PL) hydrogel nanoparticles, with a core consisting of poly[styrene-co-(N-isopropylacrylamide)] (PS-co-PNIPAM) and a PNIPAM-co-PAA shell. PAA represents polyacrylic acid which interacts with our emitting molecule 1,2-bis[4-(2-triethylammonioethoxy)phenyl]-1,2-diphenylethene dibromide (d-TPE). The electrostatic interaction between each water-soluble d-TPE molecule and two AA repeat units activates these d-TPE molecules to exhibit strong PL. Our d-TPE doped PS-co-PNIPAM/PNIPAM-co-PAA particles in water display remarkable TR PL: the emission intensity decreased in the course of heating from 2 to 80 °C and recovered during cooling from 80 to 2 °C. Such linear, reversible, and sensitive TR PL is achieved by the use of both PAA and PNIPAM as the shell polymeric chain and by careful optimization of the d-TPE to AA feed molar ratio. Thus, the emission of the d-TPE molecule is affected sensitively by temperature. In addition to such an exceptionally temperature-dependent PL, the presence of CrO4 2- resulted in the decrease of the emission intensity, which was also temperature-dependent. The present study provides a unified conceptual methodology to engineer functional water-dispersible hydrogel nanoparticles that are stimuli-responsive with the potential to advance various PL-based applications.
Keywords: photoluminescent hydrogel nanoparticles; reversible and linear thermoresponses; temperature-dependent photoluminescence; TPE derivatives

The halo+cluster system of the Galactic globular cluster NGC 1851 - Marino, A. F.; Milone, A. P.; Yong, D.; Dotter, A.; Da Costa, G.; Asplund, M.; Jerjen, H.; Mackey, D.; Norris, J.; Cassisi, S.; Sbordone, L.; Stetson, P. B.; et al. (Monthly Notices of the Royal Astronomical Society, 2014)
NGC 1851 is surrounded by a stellar component that extends more than 10 times beyond the tidal radius. Although the nature of this stellar structure is not known, it has been suggested to be a sparse halo of stars or associated with a stellar stream. We analyse the nature of this intriguing stellar component surrounding NGC 1851 by investigating its radial velocities and chemical composition, in particular in comparison with those of the central cluster analysed in a homogeneous manner. In total we observed 23 stars in the halo with radial velocities consistent with NGC 1851, and for 15 of them we infer [Fe/H] abundances. Our results show that (i) stars dynamically linked to NGC 1851 are present at least up to ̃2.5 tidal radii, supporting the presence of a halo of stars surrounding the cluster; (ii) apart from the NGC 1851 radial velocity-like stars, our observed velocity distribution agrees with that expected from Galactic models, suggesting that no other substructure (such as a stream) at different radial velocities is present in our field; (iii) the chemical abundances for the s-process elements Sr and Ba are consistent with the s-normal stars observed in NGC 1851; (iv) all halo stars have metallicities, and abundances for the other studied elements Ca, Mg and Cr, consistent with those exhibited by the cluster. The complexity of the whole NGC 1851 cluster+halo system may agree with the scenario of a tidally disrupted dwarf galaxy in which NGC 1851 was originally embedded.

UV-induced transformation and physicochemical property changes of quantum dots in the presence of air - Ruan, Xinchao; Yang, Chun; Wu, Xiaohua; Yu, Kui; Feng, Yong-Lai (Journal of Nanoparticle Research, 2014)
Engineered nanomaterials (ENMs) can be released to the environment during their lifecycles. The potential uptake by biological systems, along with uncertain distribution pathways, makes this class of materials important to study from a perspective of potential impacts to the environment and people. In this study, colloidal quantum dots (Q-dots), with diameter around 3 nm and passivated with C18H33 chains (oleic acid), were used, as a model system, to investigate the fate and the transformations of ENMs under UV irradiation in the presence of air. Before and after the UV light irradiation, the changes of the Q-dots on DNA interaction potency, and UV-Vis and fluorescence spectra are compared. When the Q-dots were exposed to UV light, the formation of water-soluble products was confirmed by UV-Vis and fluorescence spectra collected from aqueous dispersions and by the mass loss. Both the UV irradiation time and intensity were found to influence the amount of water-soluble products produced. However, before and after UV irradiation, the Q-dots exhibited little change of their DNA interaction potency. Therefore, it seems that the Q-dot surface chemical reactivity to DNA changed little, in conjunction with photooxidization of the surface passivation ligand.
Keywords: Colloidal quantum dots; UV irradiation; Water-soluble products; DNA interaction potency; Surface chemical reactivity; Transformation of nanomaterials; Environmental effects

Microstructural analysis of linear friction-welded 718 plus superalloy - Vishwakarma, K. R.; Ojo, O. A.; Wanjara, P.; Chaturvedi, M. C. (JOM, 2014)
The microstructure of Allvac 718 Plus (718 Plus; ATI, Pittsburgh, PA, USA) superalloy was examined after linear friction welding (LFW) and after standard postweld heat treatment (PWHT). The liquid phase reaction of second-phase precipitates, which are known to constitutionally liquate during conventional fusion welding, was observed in the thermomechanically affected zone (TMAZ) of the welded material. These phases included MC-type carbides, Ti-rich carbonitrides, and δ phase precipitates. This observation is contrary to the general assumption that LFW is a completely solid-state joining process. However, unlike conventional fusion welding processes that cause heat-affected zone liquation cracking in 718 Plus and many other superalloys, the LFW process did not cause cracking in 718 Plus superalloy despite the liquation of precipitates. This absence of cracking during joining is attributed to the applied compressive stress during the forging stage of the LFW process. Also, no cracking was observed after PWHT, although PWHT resulted in a microstructure that had a nonhomogeneous distribution of precipitates in the weld and the TMAZ. © 2014 Her Majesty the Queen in Right of Canada as represented by: NRC Canada.

Production, characterization, and applications of porous materials - Michailidis, Nikolaos; Tsouknidas, Alexander; Lefebvre, Louis-Philippe; Hipke, Thomas; Kanetake, Naoyuki (Advances in Materials Science and Engineering, 2014)

Structural characterization of the extracellular polysaccharide from Vibrio cholerae O1 El-Tor - Yildiz, Fitnat; Fong, Jiunn; Sadovskaya, Irina; Grard, Thierry; Vinogradov, Evgeny (PLoS ONE, 2014)
The ability to form biofilms is important for environmental survival, transmission, and infectivity of Vibrio cholerae, the causative agent of cholera in humans. To form biofilms, V. cholerae produces an extracellular matrix composed of proteins, nucleic acids and a glycoconjugate, termed Vibrio exopolysaccharide (VPS). Here, we present the data on isolation and characterization of the polysaccharide part of the VPS (VPS-PS), which has the following structure: -4)-α-GulpNAcAGly3OAc-(1-4)-β-D-Glcp-(1-4)- α-Glcp-(1-4)-α-D-Galp-(1- where α-D-Glc is partially (∼20%) replaced with α-D-GlcNAc. α-GulNAcAGly is an amide between 2-acetamido-2-deoxy-α-guluronic acid and glycine. Apparently, the polysaccharide is bound to a yet unidentified component, which gives it high viscosity and completely suppresses any NMR signals belonging to the sugar chains of the VPS. The only reliable method to remove this component at present is a treatment of the whole glycoconjugate with concentrated hydrochloric acid.
Keywords: exopolysaccharide; glucosamine; glycine; glycoconjugate; hydrochloric acid; n acetylglucosamine; biofilm; carbohydrate analysis; chemical binding; chemical modification; extracellular matrix; isolation procedure; proton nuclear magnetic resonance; structure activity relation; structure analysis; Vibrio cholerae; viscosity

Fate of palmitic, palmitoleic and eicosapentaenoic acids during anaerobic digestion of Phaeodactylum tricornutum at varying lipid concentration - Frigon, Jean-Claude; Hamani Abdou, Rekia; McGinn, Patrick J.; O'Leary, Stephen J. B.; Guiot, Serge R. (Algal Research, 2014)
The literature is showing an increasing trend in the use of microalgal biomass for the production of biofuel, with a recent keen interest for the conversion of microalgae into methane. The methane potential from Phaeodactylum tricornutum was similar for the whole algae, 362. ±. 5. L/kg total volatile solid (TVS), compared with a sample from which the lipids were extracted, at 358. ±. 6. L/kg TVS. The anaerobic digestion of long chain fatty acids (LCFAs) representative of the dominant acids found in P. tricornutum during 22. weeks of incubation demonstrated that the usual incubation time of typical anaerobic digesters (3-6. weeks) is insufficient to hydrolyze the lipids and maximize the energy yield contained in the microalgae. The results from methane potential assays targeting the LCFAs that were found in significant concentrations in P. tricornutum, namely palmitic, palmitoleic and eicosapentaenoic (EPA) acids), at concentration of 2.5 and 1.25. g/L, showed a slow but high yield with palmitic acid (802. ±. 16. L/kg), inhibition from palmitoleic acid and fair degradation of EPA (442. ±. 67. L/kg). There was a 27% increase in the methane yield from a reconstituted P. tricornutum containing 25% of LCFA compared to 10%, at 456. ±. 1 vs 363. ±. 5. mL. STP/g TVS. Increasing the free fatty acid fraction to 50% in the microalgal biomass resulted in the inhibition of the digestion after production of methane during the first 11. days of incubation.
Keywords: Anaerobic digestion; Biofuel; Fatty acids; Lipid; Methane; Microalgae; Phaeodactylum

Effect of chill parameters on the residual strain in cast 319 aluminum alloy : a neutron diffraction study - Kumar, V.; Sediako, D.; Bichler, L. (SAE International Journal of Materials and Manufacturing, 2014)
The demand for light weight vehicles continues to stimulate extensive research into the development of light weight casting alloys and optimization of their manufacturing processes. Of primary relevance are Aluminum (Al) and Magnesium (Mg) based alloys, which have successfully replaced selected iron based castings in automobiles. However, optimization of as-cast microstructure, processing and performance remains a challenge for some Al-based alloys. In this context, placement of chills in castings has been frequently used to locally manipulate the solidification conditions and microstructure of a casting. In this work, the effect of using an active copper chill on the residual strain profile of a sand-cast B319 aluminum alloy was investigated. Wedge-shaped castings were produced with three different cooling conditions: copper plate chill, copper pipe with cooling water and no chill (baseline). The effect of chill condition on the variation of residual strain in the casting was investigated using neutron diffraction approach. Diffraction from (111) and (311) reflections was studied and revealed that the (311) reflection did not exhibit appreciable strain variation at different chill conditions. In contrast, the (111) reflection exhibited a mix of tensile and compressive strains which varied with a distance from the copper chill. A copper plate chill introduced a fluctuating pattern of strain profile with tensile and compressive strain peaks, while faster cooling (copper pipe with water flow) had attenuated the residual strain profile, suggesting the need to control the chilling condition in order to achieve optimal casting performance.
Keywords: As cast microstructure; Compressive strain; Cooling conditions; Manufacturing process; Neutron diffraction studies; Residual strains; Solidification condition; Strain variation; Aluminum; Copper; Copper pipe; Copper plating; Light weight vehicles; Magnesium castings; Microstructure; Neutron diffraction; Optimization; Strain; Aluminum alloys

A simple pendulum laser interferometer for determining the gravitational constant - Parks, Harold V.; Faller, James E. (Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2014)
We present a detailed account of our 2004 experiment to measure the Newtonian constant of gravitation with a suspended laser interferometer. The apparatus consists of two simple pendulums hanging from a common support. Each pendulum has a length of 72 cm and their separation is 34 cm. A mirror is embedded in each pendulum bob, which then in combination form a Fabry-Perot cavity. A laser locked to the cavity measures the change in pendulum separation as the gravitational field is modulated due to the displacement of four 120 kg tungsten masses.
Keywords: Fabry-Perot; Gravitational constant; Laser interferometer; Physical constants; Precision measurement; Simple pendulums

Indentation and needle insertion properties of the human eye - Matthews, A.; Hutnik, C.; Hill, K.; Newson, T.; Chan, T.; Campbell, G. (Eye (Basingstoke), 2014)
PurposeCharacterization of the biomechanical properties of the human eye has a number of potential utilities. One novel purpose is to provide the basis for development of suitable tissue-mimicking material. The purpose of this study was to determine the indentation and needle insertion characteristics on human eye globes and tissue strips.MethodsAn indenter assessed the elastic response of human eye globes and tissue strips under increasing compressive loads. Needle insertion determined the force (N) needed to penetrate various areas of the eye wall.ResultsThe results demonstrated that globes underwent slightly greater indentation at the midline than at the central cornea, and corneal strips indented twofold more than scleral strips, although neither difference was significant (P=0.400 and P=0.100, respectively). Significant differences were observed among various areas of needle insertion (P<0.001). Needle insertion through the anterior sclera (adjacent to the limbus) and posterior sclera (adjacent to the optic nerve) required the greatest amount of force (0.954 and 1.005 N, respectively). The force required to penetrate the central cornea (0.518 N) was significantly lower than all other areas except the midline sclera (0.700 N)ConclusionThese data form the basis for further research into the development of a tissue-mimicking human eye construct with potential utility as a model for use in ophthalmology research and surgical teaching.
Keywords: adult; aged; biomechanics; cornea; cornea limbus; corneal strip; drug delivery system; eye; eye indentation; force; ophthalmic needle; sclera

Molecular gas clumps from the destruction of icy bodies in the β pictoris debris disk - Dent, W. R. F.; Wyatt, M. C.; Roberge, A.; Augereau, J.-C.; Casassus, S.; Corder, S.; Greaves, J. S.; De Gregorio-Monsalvo, I.; Hales, A.; Jackson, A. P.; Meredith Hughes, A.; Lagrange, A.-M.; et al. (Science, 2014)
Many stars are surrounded by disks of dusty debris formed in the collisions of asteroids, comets, and dwarf planets, but is gas also released in such events? Observations at submillimeter wavelengths of the archetypal debris disk around β Pictoris show that 0.3% of a Moon mass of carbon monoxide orbits in its debris belt. The gas distribution is highly asymmetric, with 30% found in a single clump 85 astronomical units from the star, in a plane closely aligned with the orbit of the inner planet, β Pictoris b. This gas clump delineates a region of enhanced collisions, either from a mean motion resonance with an unseen giant planet or from the remnants of a collision of Mars-mass planets.
Keywords: carbon monoxide; asteroid; carbon monoxide; collision; Mars; molecular analysis; resonance; wavelength; astronomy; attenuation; beta pictoris debris disk; cosmological phenomena; field emission; icy body destruction; moon; planet collision; steady state; velocity

Effects of fatigue on the integrity OFA frcition stir welded lap joint containing residual stresses - Bach, Michael; Merati, Ali; Gharghouri, Michael (Advanced Materials Research, 2014)
This research uses a non-destructive method of neutron diffraction to measure the tri-axial residual stresses in a friction stir welded aerospace fuselage component: a stringer-to-skin lap joint. Two different specimens were examined. Fatigue testing was performed on both specimens to determine their fatigue lives. Effects of the different components of residual stresses were examines and related to fatigue performance. A combination of fractography, hardness testing, and residual stress measurement was used to predict areas of high probability of structural failure in the friction stir welded lap joints.
Keywords: Fatigue of materials; Fatigue testing; Fracture mechanics; Joints (structural components); Neutron diffraction; Nondestructive examination; Stringers; Welding; Crack nucleation; Fatigue performance; Friction stir; Lap joint; Structural failure; Tri-axial; Residual stresses

Improving the performance of high voltage LiMn1.5 Ni0.5 O4 cathode material by carbon coating - Niketic, Svetlana; Couillard, Martin; MacNeil, Dean; Abu-Lebdeh, Yaser (Journal of Power Sources, 2014)
In this work, the high voltage LiMn1.5Ni0.5O 4 cathode material has been synthesized as octadecahedron crystals with a disordered spinel structure and has been coated with a carbon layer from two different precursors (sucrose and Xerogel carbon) to improve its performance in Li-ion batteries. The effect of carbon coating on the physical and electrochemical properties of the crystals has been evaluated using X-ray diffraction (XRD), Infrared (IR) and Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental and surface area (BET) analyses and battery cycling at different charge/discharge rates and temperatures. It was found that the amount of carbon, present as a thin layer (5-10 nm) and estimated at <1 w.t.%, causes an increase in electronic conductivity with no effect on crystal structure. Battery results of the cathode material in half cells show that carbon coating greatly improves the discharge capacity, rate capability at room temperature and 60 °C as well as cycling stability. Moreover, the material coated from Xerogel carbon shows the highest capacity at 10 C rate and 60 °C.
Keywords: High voltage; Li-ion battery; Spinel cathode; Carbon coating

Toughening mechanisms in interfacially modified HDPE/thermoplastic starch blends - Taguet, Aurélie; Bureau, Martin N.; Huneault, Michael A.; Favis, Basil D. (Carbohydrate Polymers, 2014)
The mechanical behavior of polymer blends containing 80 wt% of HDPE and 20 wt% of TPS and compatibilized with HDPE-g-MA grafted copolymer was investigated. Unmodified HDPE/TPS blends exhibit high fracture resistance, however, the interfacial modification of those blends by addition of HDPE-g-MA leads to a dramatic drop in fracture resistance. The compatibilization of HDPE/TPS blends increases the surface area of TPS particles by decreasing their size. It was postulated that the addition of HDPE-g-MA induces a reaction between maleic anhydride and hydroxyl groups of the glycerol leading to a decrease of the glycerol content in the TPS phase. This phenomenon increases the stiffness of the modified TPS particles and stiffer TPS particles leading to an important reduction in toughness and plastic deformation, as measured by the EWF method. It is shown that the main toughening mechanism in HDPE/TPS blends is shear-yielding. This article demonstrates that stiff, low diameter TPS particles reduce shear band formation and consequently decrease the resistance to crack propagation.
Keywords: Starch; Glycerol; Toughness; Blends; Compatibilization

Origin of non-SEI related coulombic efficiency loss in carbons tested against Na and Li - Memarzadeh Lotfabad, Elmira; Kalisvaart, Peter; Kohandehghan, Alireza; Karpuzov, Dimitre; Mitlin, David (Journal of Materials Chemistry A, 2014)
Partially ordered but not graphitized carbons are widely employed for sodium and lithium ion battery (NIB and LIB) anodes, either in their pure form or as a secondary supporting phase for oxides, sulfides and insertion electrodes. These "pseudographitic" materials ubiquitously display a poor initial coulombic efficiency (CE), which has been historically attributed to solid electrolyte interface (SEI) formation on their large surface areas (up to ∼2500 m2 g-1). Here we identify the other sources CE loss by examining a pseudographitic carbon with a state-of-the-art capacity (>350 mA h g-1 for NIB, >800 mA h g-1 for LIB), but with a purposely designed low surface area (14.5 m2 g-1) that disqualifies SEI from having a substantial role. During the initial several (<5) cycles both Na and Li are irreversibly trapped in the bulk, with the associated CE loss occurring at higher desodiation/delithiation voltages. We measure a progressively increasing graphene interlayer spacing and a progressively increasing Raman G band intensity, indicating that the charge carriers become trapped not only at the graphene defects but also between the graphene planes hence causing them to both dilate and order. For the case of Li, we also unambiguously detected irreversible metal underpotential deposition ("nanoplating") within the nanopores at roughly below 0.2 V. It is expected that in conventional high surface area carbons these mechanisms will be a major contributor to CE loss in parallel to classic SEI formation. Key implications to emerge from these findings are that improvements in early cycling CE may be achieved by synthesizing pseudographitic carbons with lower levels of trapping defects, but that for LIBs the large cycle 1 CE loss may be unavoidable if highly porous structures are utilized.
Keywords: Coulombic efficiency

Development of a Compton imager based on bars of scintillator - MacLeod, A. M. L.; Boyle, P. J.; Hanna, D. S.; Saull, P. R. B.; Sinclair, L. E.; Seywerd, H. C. J. (Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014)
We have developed a compact Compton gamma-ray imager with a large field of view and a low channel-count that is capable of quickly localizing gamma-ray sources in the few hundred keV - several MeV range. The two detector planes (scatter and absorber) employ bars of NaI(Tl) read out by photomultiplier tubes (PMTs) located at each end. The long-range imaging performance has been tested from 392 keV to 1274 keV. An angular resolution measure of 2.72±0.06° and an efficiency of (1.79±0.04)×10-³ at 662 keV is obtained. A ¹³⁷Cs (662 keV) source equivalent to a 10 mCi source 40 m away can be located in 60 s with an uncertainty of about a degree. No significant degradation in imaging performance is observed for source angles up to 40° off axis.
Keywords: Compton imaging; Compton telescope; Pulse-height sharing; Radiation detection; Security; Scintillator

Electrolyte effect on gelation behavior of oppositely charged nanocrystalline cellulose and polyelectrolyte - Lu, Ang; Song, Yongbo; Boluk, Yaman (Carbohydrate Polymers, 2014)
The electrolyte (NaCl) influences on the sol-gel transition of the complex solution composed of oppositely charged nanocrystalline cellulose (NCC) and polyelectrolyte (quaternized hydroxyethylcellulose ethoxylate, QHEC) were investigated by the rheological means in the present paper. Winter and Chambon theory was applicable to describe the sol-gel transition, and the critical gel points have been successfully determined. When increasing the NaCl concentration, more NCC were needed to form a critical gel due to the screening of the electrostatic interaction, and the larger loss tangent and relaxation exponent (n) values at the gel point demonstrated a less elastic nature of the complex solution with more NaCl. The results indicated the gel network was composed of entanglements and association of QHEC (as polymer network), as well as the electrostatic adsorption interaction between QHEC chains and NCC rods (as cross-linking). With the addition of NaCl, the screening effect led to the enhancement of the entanglements and weakening of the electrostatic adsorption, however, the gel strength decreased with increasing the NaCl amount, suggesting the electrostatic adsorption interaction played a more dominant role than the entanglements when the gel was formed. Moreover, the exponents of the scaling law η0 ∝-γ and Ge ∝z of the QHEC/NCC/NaCl solution revealed that the scaling law n = z/(z + γ) between n, γ, and z was only feasible at the highest NaCl concentration, as a result of that the intermolecular electrostatic interaction was completely screened, indicating the scaling law was only feasible when intermolecular interaction was small enough to be neglected.
Keywords: Nanocrystalline cellulose; Gelation; Opposite charge; Electrolytes

High-throughput quantitative analysis of domoic acid directly from mussel tissue using Laser Ablation Electrospray Ionization - tandem mass spectrometry - Beach, Daniel G.; Walsh, Callee M.; McCarron, Pearse (Toxicon, 2014)
Eliminating sample extraction or liquid chromatography steps from methods for analysis of the neurotoxin Domoic Acid (DA) in shellfish could greatly increase throughput in food safety testing laboratories worldwide. To this end, we have investigated the use of Laser Ablation Electrospray Ionization (LAESI) with tandem mass spectrometry (MS/MS) detection for DA analysis directly from mussel tissue homogenates without sample extraction, cleanup or separation. DA could be selectively detected directly from mussel tissue homogenates using MS/MS in selected reaction monitoring scan mode. The quantitative capabilities of LAESI-MS/MS for DA analysis from mussel tissue were evaluated by analysis of four mussel tissue reference materials using matrix-matched calibration. Linear response was observed from 1 mg/kg to 40 mg/kg and the method limit of detection was 1 mg/kg. Results for DA analysis in tissue within the linear range were in good agreement with two established methods, LC-UV and LC-MS/MS (recoveries from 103 to 125%). Beyond the linear range, extraction and clean-up were required to achieve good quantitation. Most notable is the extremely rapid analysis time of about 10 s per sample by LAESI-MS/MS, which corresponds to a significant increase in sample throughput compared with existing methodology for routine DA analysis.
Keywords: Ambient ionization; Direct analysis; Amnesic shellfish poisoning (ASP); Algal toxin; Shellfish testing

Experimental and modeling study on charge storage/transfer mechanism of graphene-based supercapacitors - Ban, Shuai; Jing, Xie; Zhou, Hongjun; Zhang, Lei; Zhang, Jiujun (Journal of Power Sources, 2014)
A symmetrical graphene-based supercapacitor is constructed for studying the charge-transfer mechanism within the graphene-based electrodes using both experiment measurements and molecular simulation. The in-house synthesized graphene is characterized by XRD, SEM and BET measurements for morphology and surface area. It is observed that the electric capacity of graphene electrode can be reduced by both high internal resistance and limited mass transfer. Computer modeling is conducted at the molecular level to characterize the diffusion behavior of electrolyte ions to the interior of electrode with emphasis on the unique 2D confinement imposed by graphene layers. Although graphene powder poses a moderate internal surface of 400 m2 g -1, the capacitance performance of graphene electrode can be as good as that of commercial activated carbon which has an overwhelming surface area of 1700 m2 g-1. An explanation to this abnormal correlation is that graphene material has an intrinsic capability of adaptively reorganizing its microporous structure in response to intercalation of ions and immergence of electrolyte solvent. The accessible surface of graphene is believed to be dramatically enlarged for ion adsorption during the charging process of capacitor.
Keywords: Graphene; Aqueous electrolyte; Electric double layer supercapacitor; Mass transfer; Ion adsorption; Molecular simulation

β-Carotene autoxidation: oxygen copolymerization, non-vitamin A products and immunological activity - Burton, Graham W.; Daroszewski, Janusz; Nickerson, James G.; Johnston, James B.; Mogg, Trevor J.; Nikiforov, Grigory B. (Canadian Journal of Chemistry, 2014)
Carotenoids are reported to have immunological effects independent of vitamin A activity. Although antioxidant activity has been suggested as a basis of action, the ability of carotenoids to autoxidize to numerous non-vitamin A products with immunological activity is an alternative yet to be fully explored. We have undertaken a systematic study of β-carotene autoxidation and tested the product mixture for immunological activity. Autoxidation proceeds predominantly by oxygen copolymerization, leading to a defined, reproducible product corresponding to net uptake of almost 8 molar equivalents of oxygen. The product, termed OxC-beta, empirical formula C40H60O15 versus C40H56 for β-carotene, contains more than 30% oxygen (w/w) and 85% β-carotene oxygen copolymers (w/w) as well as minor amounts of many C8−C18 norisoprenoid compounds. No vitamin A or higher molecular weight norisoprenoids are present. The predominance of polymeric products has not been reported previously. The polymer appears to be a less polymerized form of sporopollenin, a biopolymer found in exines of spores and pollen. Autoxidations of lycopene and canthaxanthin show a similar predominance of polymeric products. OxC-beta exhibits immunological activity in a PCR gene expression array, indicating that carotenoid oxidation produces non-vitamin A products with immunomodulatory potential.
Keywords: β-carotene autoxidation; oxygen copolymer; non-vitamin A oxidation products; immune function; gene expression

A sensitive nonenzymatic hydrogen peroxide sensor using cadmium oxide nanoparticles/multiwall carbon nanotube modified glassy carbon electrode - Butwong, Nutthaya; Zhou, Lin; Ng-eontae, Wittaya; Burakham, Rodjana; Moore, Eric; Srijaranai, Supalax; Luong, John H.T.; Glennon, Jeremy D. (Journal of electroanalytical chemistry, 2014)
A simple sensing scheme for hydrogen peroxide has been described by electrochemical deposition of cadmium oxide (CdO) nanoparticles with ∼50 nm in diameter on a glassy carbon (GC) electrode modified with multiwall carbon nanotubes (MWCNT). The CdO/MWCNT modified sensor, with a surface coverage of 1.13 × 10−8 mol/cm2, displayed high synergistic electrocatalytic activity for H2O2. The sensor was capable of reducing H2O2 at −1.2 V vs. Ag/AgCl (H2O2 + 2H+ + 2e− → 2H2O) in a broad pH range. At the optimal pH 7, the sensor exhibited a detection limit of 0.1 μM, broad linearity from 0.5 to 200 μM, good reproducibility (RSD of 5.9%), and long-term stability. Uric acid, ascorbic acid and dopamine up to 100 μM provoked no signal response, attesting selectivity of the CdO/MWCNT modified electrode for hydrogen peroxide.
Keywords: Cadmium oxide; Multiwall carbon nanotube; Glassy carbon electrode; Hydrogen peroxide

Identification and functional characterization of a flax UDP-glycosyltransferase glucosylating secoisolariciresinol (SECO) into secoisolariciresinol monoglucoside (SMG) and diglucoside (SDG) - Ghose, Kaushik; Selvaraj, Kumarakurubaran; McCallum, Jason; Kirby, Chris W.; Sweeney-Nixon, Marva; Cloutier, Sylvie J.; Deyholos, Michael; Datla, Raju; Fofana, Bourlaye (BMC Plant Biology, 2014)
Background: Lignans are a class of diphenolic nonsteroidal phytoestrogens often found glycosylated in planta. Flax seeds are a rich source of secoisolariciresinol diglucoside (SDG) lignans. Glycosylation is a process by which a glycosyl group is covalently attached to an aglycone substrate and is catalyzed by uridine diphosphate glycosyltransferases (UGTs). Until now, very little information was available on UGT genes that may play a role in flax SDG biosynthesis. Here we report on the identification, structural and functional characterization of 5 putative UGTs potentially involved in secoisolariciresinol (SECO) glucosylation in flax. Results: Five UGT genes belonging to the glycosyltransferases' family 1 (EC 2.4.x.y) were cloned and characterized. They fall under four UGT families corresponding to five sub-families referred to as UGT74S1, UGT74T1, UGT89B3, UGT94H1, UGT712B1 that all display the characteristic plant secondary product glycosyltransferase (PSPG) conserved motif. However, diversity was observed within this 44 amino acid sequence, especially in the two peptide sequences WAPQV and HCGWNS known to play a key role in the recognition and binding of diverse aglycone substrates and in the sugar donor specificity. In developing flax seeds, UGT74S1 and UGT94H1 showed a coordinated gene expression with that of pinoresinol-lariciresinol reductase (PLR) and their gene expression patterns correlated with SDG biosynthesis. Enzyme assays of the five heterologously expressed UGTs identified UGT74S1 as the only one using SECO as substrate, forming SECO monoglucoside (SMG) and then SDG in a sequential manner.Conclusion: We have cloned and characterized five flax UGTs and provided evidence that UGT74S1 uses SECO as substrate to form SDG in vitro. This study allowed us to propose a model for the missing step in SDG lignan biosynthesis.
Keywords: Flax; Glucosylation; Glycosyltranferases; Lignan; SDG; Secoisolariciresinol; UGTs

Deracemization of 2-methyl-1,2,3,4-tetrahydroquinoline using mutant cyclohexylamine oxidase obtained by iterative saturation mutagenesis - Li, Guangyue; Ren, Jie; Yao, Peiyuan; Duan, Yitao; Zhang, Hailing; Wu, Qiaqing; Feng, Jinhui; Lau, Peter C. K.; Zhu, Dunming (ACS catalysis, 2014)
The current toolkit of biocatalysts for the production of enantiomerically pure chiral amines is largely restricted to amine transaminases, ammonia lyases, or the genetic variants of monoamine oxidase N(MAO-N) from Aspergillus niger. Flavin-dependent amine oxidases have the apparent advantage of using molecular oxygen as a stoichiometric oxidant and their reactions are irreversible. To expand the toolkit and increase the substrate spectrum of a bacterial and flavin-dependent cyclohexylamine oxidase (CHAO) to enable deracemization of secondary amines, saturation mutagenesis of 11 amino acid residues located around the cyclohexanone substrate within a distance of 5 Å, followed by iterative saturation mutagenesis of four beneficial mutants, were performed. Screening with 2-methyl-1,2,3,4-tetrahydroquinoline as the substrate generated two improved CHAO variants, T198FL199S and T198FL199SM226F, that exhibited up to 406 times higher catalytic efficiency than the wild-type CHAO. Besides, high stereoselectivity for 2-methyl-1,2,3,4-tetrahydroquinoline and other 2-substituted-1,2,3,4-tetrahydroquinolines was demonstrated. In particular, deracemization of 2-methyl-1,2,3,4-tetrahydroquinoline by Escherichia coli whole cells expressing CHAO mutant T198FL199SM226F led to the production of (R)-2-methyl-1,2,3,4-tetrahydroquinoline with high yield (76%) and enantiomeric excess (ee, 98%). Tetrahydroquinolines are important building blocks of natural and synthetic products useful in the pharmaceutical and agrochemical industries.
Keywords: biocatalysis; amine oxidase; iterative saturation mutagenesis; chiral amines; deracemization

Simultaneous profiling of seed-associated bacteria and fungi reveals antagonistic interactions between microorganisms within a shared epiphytic microbiome on Triticum and Brassica seeds - Links1, Matthew G.; Demeke, Tigst; Gräfenhan, Tom; Hill, Janet E.; Hemmingsen, Sean M.; Dumonceaux, Tim J. (New phytologist, 2014)
In order to address the hypothesis that seeds from ecologically and geographically diverse plants harbor characteristic epiphytic microbiota, we characterized the bacterial and fungal microbiota associated with Triticum and Brassica seed surfaces. The total microbial complement was determined by amplification and sequencing of a fragment of chaperonin 60 (cpn60). Specific microorganisms were quantified by qPCR. Bacteria and fungi corresponding to operational taxonomic units (OTU) that were identified in the sequencing study were isolated and their interactions examined. A total of 5477 OTU were observed from seed washes. Neither total epiphytic bacterial load nor community richness/evenness was significantly different between the seed types; 578 OTU were shared among all samples at a variety of abundances. Hierarchical clustering revealed that 203 were significantly different in abundance on Triticum seeds compared with Brassica. Microorganisms isolated from seeds showed 99-100% identity between the cpn60 sequences of the isolates and the OTU sequences from this shared microbiome. Bacterial strains identified as Pantoea agglomerans had antagonistic properties toward one of the fungal isolates (Alternaria sp.), providing a possible explanation for their reciprocal abundances on both Triticum and Brassica seeds. cpn60 enabled the simultaneous profiling of bacterial and fungal microbiota and revealed a core seed-associated microbiota shared between diverse plant genera.
Keywords: biocontrol; core microbiome; cpn60 universal target; DNA barcode; epiphytes; seed microbiota

Structure determinants for the substrate specificity of Acyl-CoA Δ9 desaturases from a marine copepod - Meesapyodsuk, Dauenpen; Qiu, Xiao (ACS Chemical Biology, 2014)
In contrast to soluble acyl-ACP desaturases from plants, little is known about the structure-guiding principle underlying substrate specificity and regioselectivity of membrane-bound acyl-CoA desaturases from animals, mainly due to lack of the three-dimensional structure information. Here we report identification of two homologous membrane-bound acyl-CoA Δ9 desaturases (ChDes9-1 and ChDes9-2) from the marine copepod Calanus hyperboreus that accumulates more than 90% of total storage lipids in the form of wax esters. ChDes9-2 is a common Δ9 desaturase with substrate specificity to long chain fatty acid 18:0, while ChDes9-1 is a new type of Δ9 desaturase introducing a Δ9 double bond into a wide range of very long chain fatty acids ranging from 20:0 to 26:0. Reciprocal domain swapping and site-directed mutagenesis guided by the membrane topology revealed that presence or absence of an amphipathic and bulky residue, tyrosine, in the middle of the second transmembrane domain was important in determining the substrate specificity of the two desaturases. To examine the mechanistic structure for the substrate specificity, tyrosine-scanning mutagenesis was employed to systematically substitute the residues in the transmembrane domain of the very long chain desaturase. The results showed that the transmembrane domain formed an α-helix structure probably involved in formation of the substrate-binding pocket and the corresponding residue of the tyrosine likely resided at the critical position within the pocket mediating the interaction with the substrates, thereby specifying the chain length of the substrates.

The emerging biofuel crop Camelina sativa retains a highly undifferentiated hexaploid genome structure - Kagale, Sateesh; Koh, Chushin; Nixon, John; Bollina, Venkatesh; Clarke, Wayne E.; Tuteja, Reetu; Spillane, Charles; Robinson, Stephen J.; Links, Matthew G.; Clarke, Carling; Higgins, Erin E.; Huebert, Terry; et al. (Nature communications, 2014)
Camelina sativa is an oilseed with desirable agronomic and oil-quality attributes for a viable industrial oil platform crop. Here we generate the first chromosome-scale high-quality reference genome sequence for C. sativa and annotated 89,418 protein-coding genes, representing a whole-genome triplication event relative to the crucifer model Arabidopsis thaliana. C. sativa represents the first crop species to be sequenced from lineage I of the Brassicaceae. The well-preserved hexaploid genome structure of C. sativa surprisingly mirrors those of economically important amphidiploid Brassica crop species from lineage II as well as wheat and cotton. The three genomes of C. sativa show no evidence of fractionation bias and limited expression-level bias, both characteristics commonly associated with polyploid evolution. The highly undifferentiated polyploid genome of C. sativa presents significant consequences for breeding and genetic manipulation of this industrial oil crop.
Keywords: Biological sciences; Biotechnology; Genetics

One-step antibody immobilization-based rapid and highly-sensitive sandwich ELISA procedure for potential in vitro diagnostics - Vashist, Sandeep Kumar; Schneider, E. Marion; Lam, Edmond; Hrapovic, Sabahudin; Luong, John H. T. (Scientific reports, 2014)
An improved enzyme-linked immunosorbent (ELISA) assay using one-step antibody immobilization has been developed for the detection of human fetuin A (HFA), a specific biomarker for atherosclerosis and hepatocellular carcinoma. The anti-HFA formed a stable complex with 3-aminopropyltriethoxysilane (APTES) by ionic and hydrophobic interactions. The complex adsorbed on microtiter plates exhibited a detection range of 4.9 pg mL-1 to 20 ng mL-1 HFA, with a limit of detection of 7 pg mL-1. Furthermore, an analytical sensitivity of 10 pg mL-1 was achieved, representing a 51-fold increase in sensitivity over the commercial sandwich ELISA kit. The results obtained for HFA spiked in diluted human whole blood and plasma showed the same precision as the commercial kit. When stored at 4°C in 0.1 M phosphate-buffered saline (PBS, pH 7.4), the anti-HFA bound microtiter plates displayed no significant decrease in their functional activity after two months. The new ELISA procedure was extended for the detection of C-reactive protein, human albumin and human lipocalin-2 with excellent analytical performance.
Keywords: Diagnostic markers; Immunological techniques

Toward high-performance, greener, and low-vulnerability munitions with the RIGHTTRAC technology demonstrator program - Brochu, Sylvie; Brassard, M.; Thiboutot, Sonia; Ampleman, Guy; Brousseau, Patrick; Petre, Catalin Florin; Côté, F.; Poulin, I.; Diaz, Emmanuela; Sunahara, Geoffrey I.; Hawari, Jalal; Monteil-Rivera, Fanny; et al. (International journal of energetic materials and chemical propulsion, 2014)
The revolutionary insensitive, green, and healthier training technology with reduced adverse contamination (RIGHTTRAC) program is a 5-year technology demonstration program (TDP) aimed at showing that green and insensitive munitions have better properties than current munitions, and that it is feasible to implement safer weapon solutions that would ease the environmental pressure on ranges and training areas and decrease the health hazards for the users. The goals of this TDP are to reach a near-zero dud rate and to eliminate the potential for research development explosive (RDX) contamination as well as the use of toxic and carcinogenic compounds. This will be done by performing significant improvements to the fuzing system, the main explosive charge and the gun propellant. The vehicle used for this demonstration is a 105-mm army artillery munition (high-explosive Ml), currently filled with Composition B (a 60:40 RDX:TNT mix) and using a single-base gun propellant (Ml formulation). The aim of this communication is to provide an overview of the project and to describe the steps taken to evaluate the environmental properties of the chosen propellant and explosive formulations. At its completion, it is believed that this project will have provided the required data to assess the long-term effects of the munitions on the environment right at an early stage of the weapon development cycle, and that this can be cost effective in the long run. This will help sustain military training while preserving our resources, as well as shaping the future of weapon system development.
Keywords: RIGHTTRAC; insensitive munition; LOVA; GIM; ecotoxicology

Genetics and breeding for clubroot resistance in Canadian spring canola (Brassica napus L.) - Rahman, H.; Peng, G.; Yu, F.; Falk, K.C.; Kulkarni, M.; Selvaraj, G. (Canadian journal of plant pathology, 2014)
Clubroot disease caused by Plasmodiophora brassicae Woronin is a concern to the canola (Brassica napus L.) growers in Canada. A crop management strategy that includes deployment of genetic resistance and appropriate cultural practices is needed for long-term management of this disease. Resistance to the P. brassicae pathotypes present in Canada has been found in the primary and secondary gene pools of spring B. napus canola. Some of these sources, such as winter canola Mendel, rutabaga and Pak Choi (Brassica rapa L.) Flower Nabana, were used in genetic studies and breeding for the development of clubroot-resistant canola cultivars. A dominant gene in Mendel and Flower Nabana was found to confer resistance to P. brassicae pathotype 3, while a simple or a complex genetic control of resistance was found in rutabaga. The clubroot resistance (CR) gene in Flower Nabana was mapped to chromosome A3, and molecular markers linked to the CR gene were identified for use in marker-assisted breeding (MAB). Using the CR genes from Mendel and rutabaga, several clubroot-resistant spring canola lines were developed. Often the CR genes of Mendel and rutabaga conferring resistance to pathotype 3 also conferred resistance to other pathotypes of P. brassicae found in Canada, including pathotypes 5, 6 and 8. The CR gene of Flower Nabana was introgressed into B. napus and B. rapa canola through MAB. Since single-gene controlled resistance can be eroded, other strategies such as pyramiding different CR genes into B. napus canola should be considered for durable resistance.
Keywords: Brassica napus; breeding; clubroot resistance; gene introgression; genetics; mapping; Plasmodiophora brassicae; spring canola

Study of azoles as bifunctional additives for proton exchange membranes melt-processing from LSC and SSC perfluorosulfonic acid ionomers - Mokrini, Asmae (Polymer Electrolyte Fuel Cells 14 (PEFC 14), 2014)
This work investigates the potential use of azoles as bifunctional additives for proton exchange membranes (PEM) manufacturing through direct melt-processing of acidic ionomers. The development of high-volume manufacturing processes to prototype PEM fuel cell components with a reduced number of steps is vital to reduce system cost and complexity, and to meet the demands of high volume production and durability requirements especially for automotive applications. The strong ionic associations in ionomers act generally as physical cross-links, increasing by several orders of magnitude both melt-viscosities and relaxation times, resulting in ionomeric materials that are very difficult to melt-process with high shear rate processes such as melt-casting or melt-blowing. The strength of the ionic interactions in ionomers, and hence their physical and mechanical properties, depends on the acidity of the pendent anion. Polymers modified with the stronger acid, such as sulfonic acid (pKa~1), exhibit more dramatic changes in thermal, viscoelastic, and rheological properties than those modified with the weaker carboxylic acid (pKa~4-5). However, most ionomers may be melt-processed in very low shear rate operations such as compression-molding, which reveals that these ionic associations are not permanent cross-links and can be reversibly disrupted under suitable conditions. The approach investigated is based on the use of selected bi-functional additives that act as a SO3H groups protection and a melt-processing aid.[1] The additives selected are highly polar additives with relatively high boiling points that are expected to interact with the ion-rich aggregates that compose the nanophase separation in ionomers and act as plasticizers which expectantly improve the viscoelastic behavior during melt processing. Additives from the azole family, imidazole, 1,2,4-triazole and benzimidazole have been investigated as potential bifunctional additives. This presentation, will discuss the results obtained with four commercial PFSA ionomers Nafion® DE-2020 and NR-40 with long side chain (LSC), and Aquivion® D83-24B and D79-20BS with short side chain (SSC).

Optimization of triacylglycerol-estolide analysis by matrix-assissted laser desportion/ionization-mass spectrometry - Zhang, Haixia; Smith, Mark A.; Purves, Randy W. (Journal of American Oil Chemists' Society, 2014)
Acylglycerols containing more than three acyl groups (TAG-estolides) have been reported in plant seed oils and oil from ergot fungus. These TAG-estolides have considerable potential for industrial use, however, costs of producing synthetic TAG-estolides limits their use in large-scale applications. Identification and structural characterization of additional natural sources of TAG-estolides has been restricted by their complexity and limitations of current analytical techniques. In this work, detection and characterization of TAG-estolides was optimized for use with MALDI-TOF-MS. Eight commonly used matrices were compared; 2,5-dihydroxybenzoic acid (DHB) and 2,4,6- trihydroxyacetophenone (THAP) gave good quality mass spectra. Matrix additives were examined and lithium was the most suitable, since MS/MS spectra of lithiated TAG-estolides provided the most informative fragmentation using an optimized method. The matrix solution pH was examined, and for THAP, replacing LiCl with 10-40 mM LiOH resulted in a slightly basic pH and significantly more intense TAG-estolide signals (up to eightfold higher). Since DHB is acidic, a larger amount of LiOH (>150 mM) was required for the matrix solution to become basic, leading to ion suppression and reduced signal intensities. Thus, for TAG-estolide analysis, THAP with ~20 to 30 mM LiOH gives the highest quality spectra and the most informative MS/MS fragmentation.
Keywords: DHB; Ergot oil; Estolide; MALDI-MS; THAP; Triacylglycerol

Brassica villosa, a system for studying non-glandular trichomes and genes in the Brassicas - Nayidu, N.K.; Tan, Y.; Taheri, A.; Li, X.; Bjorndahl, T.C.; Nowak, J.; Wishart, D.S.; Hegedus, D.; Gruber, M.Y. (Plant Molecular Biology, 2014)
Brassica villosa is a wild Brassica C genome species with very dense trichome coverage and strong resistance to many insect pests of Brassica oilseeds and vegetables. Transcriptome analysis of hairy B. villosa leaves indicated higher expression of several important trichome initiation genes compared with glabrous B. napus leaves and consistent with the Arabidopsis model of trichome development. However, transcripts of the TRY inhibitory gene in hairy B. villosa were surprisingly high relative to B. napus and relative transcript levels of SAD2, EGL3, and several XIX genes were low, suggesting potential ancillary or less important trichome-related roles for these genes in Brassica species compared with Arabidopsis. Several antioxidant, calcium, non-calcium metal and secondary metabolite genes also showed differential expression between these two species. These coincided with accumulation of two alkaloid-like compounds, high levels of calcium, and other metals in B. villosa trichomes that are correlated with the known tolerance of B. villosa to high salt and the calcium-rich natural habitat of this wild species. This first time report on the isolation of large amounts of pure B. villosa trichomes, on trichome content, and on relative gene expression differences in an exceptionally hairy Brassica species compared with a glabrous species opens doors for the scientific community to understand trichome gene function in the Brassicas and highlights the potential of B. villosa as a trichome research platform.
Keywords: Brassica napus; Brassica villosa; Global gene expression; Metals; Secondary metabolites; Trichome preparations

An EAR-dependent regulatory module promotes male germ cell division and sperm fertility in Arabidopsis - Borg, M.; Rutley, N.; Kagale, S.; Hamamura, Y.; Gherghinoiu, M.; Kumar, S.; Sari, U.; Esparza-Franco, M.A.; Sakamoto, W.; Rozwadowski, K.; Higashiyama, T.; Twell, D. (Plant Cell, 2014)
The production of the sperm cells in angiosperms requires coordination of cell division and cell differentiation. In Arabidopsis thaliana, the germline-specific MYB protein DUO1 integrates these processes, but the regulatory hierarchy in which DUO1 functions is unknown. Here, we identify an essential role for two germline-specific DUO1 target genes, DAZ1 and DAZ2, which encode EAR motif-containing C2H2-type zinc finger proteins. We show that DAZ1/DAZ2 are required for germ cell division and for the proper accumulation of mitotic cyclins. Importantly, DAZ1/DAZ2 are sufficient to promote G2- to M-phase transition and germ cell division in the absence of DUO1. DAZ1/DAZ2 are also required for DUO1-dependent cell differentiation and are essential for gamete fusion at fertilization. We demonstrate that the two EAR motifs in DAZ1/DAZ2 mediate their function in the male germline and are required for transcriptional repression and for physical interaction with the corepressor TOPLESS. Our findings uncover an essential module in a regulatory hierarchy that drives mitotic transition in male germ cells and implicates gene repression pathways in sperm cell formation and fertility.

Bond coat engineering influence on the evolution of the microstructure, bond strength, and failure of TBCs subjected to thermal cycling - Lima, R. S.; Nagy, D.; Marple, B. R. (Journal of Thermal Spray Technology, 2014)
Different types of thermal spray systems, including HVOF (JP5000 and DJ2600-hybrid), APS (F4-MB and Axial III), and LPPS (Oerlikon Metco system) were employed to spray CoNiCrAlY bond coats (BCs) onto Inconel 625 substrates. The chemical composition of the BC powder was the same in all cases; however, the particle size distribution of the powder employed with each torch was that specifically recommended for the torch. For optimization purposes, these BCs were screened based on initial evaluations of roughness, porosity, residual stress, relative oxidation, and isothermal TGO growth. A single type of standard YSZ top coat was deposited via APS (F4MB) on all the optimized BCs. The TBCs were thermally cycled by employing a furnace cycle test (FCT) (1080 °C-1 h—followed by forced air cooling). Samples were submitted to 10, 100, 400, and 1400 cycles as well as being cycled to failure. The behavior of the microstructures, bond strength values (ASTM 633), and the TGO evolution of these TBCs, were investigated for the as-sprayed and thermally cycled samples. During FCT, the TBCs found to be both the best and poorest performing and had their BCs deposited via HVOF. The results showed that engineering low-oxidized BCs does not necessarily lead to an optimal TBC performance. Moreover, the bond strength values decrease significantly only when the TBC is about to fail (top coat spall off) and the as-sprayed bond strength values cannot be used as an indicator of TBC performance.
Keywords: bond coat; bond strength; CoNiCrAlY; furnace cycle testing (FCT); TBC

Thermal cycling assessment of steel-based thermal barrier coatings for Al protection - Poirier, Dominique; Lamarre, Jean-Michel; Legoux, Jean-Gabriel (Journal of Thermal Spray Technology, 2014)
There is a strong interest from the transportation industry to achieve vehicle weight reduction through the replacement of steel components by aluminum parts. For some applications, aluminum requires protective coatings due to its limited wear and lower temperature resistance compared to steel. The objective of this study was to assess the potential of amorphous-type plasma-sprayed steel coatings and conventional arc-sprayed steel coatings as thermal barrier coatings, mainly through the evaluation of their spalling resistance under thermal cycling. The microstructures of the different coatings were first compared via SEM. The amorphicity of the coatings produced via plasma spraying of specialized alloyed steel and the crystalline phases of the conventional arc-sprayed steel coatings were confirmed through x-ray diffraction. The thermal diffusivity of all coatings produced was measured to be about a third of that of bulk stainless steel. Conventional arc-sprayed steel coatings typically offered better spalling resistance under thermal cycling than steel-based amorphous coatings due probably to their higher initial bond strength. However, the presence of vertical cracks in the steel-based amorphous coatings was found to have a beneficial effect on their thermal cycling resistance. The amorphous plasma-sprayed steel coatings presented indications of recrystallization after their exposure to high temperature.
Keywords: amorphous structure; atmospheric plasma spray; steel; thermal barrier coatings; thermal cycling; wire arc spray

Simultaneous over-expressing of an acyl-ACP thioesterase (FatB) and silencing of acyl-acyl carrier protein desaturase (SAD) by artifical microRNAs increases saturated fatty acid levels in Brassica napus seeds - Sun, Jin-Yue; Hammerlindl, Joe; Forseille, Li; Zhang, Haixia; Smith, Mark A. (Plant Biotechnology Journal, 2014)
No temperate oilseeds crops are available that produce oil with a high saturated fatty acid content. To achieve such a profile, Brassica napus cv. DH12075 was engineered by simultaneous seed-specific over-expression of a native fatty acyl-ACP thioesterase B [BnFatB(2)] and artificial microRNA-mediated down-regulation of eight endogenous genes encoding putative stearoyl-ACP desaturases (BnSADs). Semi-quantitative RT-PCR analysis of transformed lines showed that the BnFatB(2) gene was highly over-expressed and the eight putative SAD genes were strongly down-regulated in developing seed demonstrating the successful application of microRNA as a tool for down-regulation of genes in the allotetraploid plant B. napus. Analysis of seed triacylglycerol (TAG) composition revealed that all lines contained high levels of palmitic acid (16:0) and moderately increased levels of stearic acid (18:0). Total saturated fatty acid content was increased from 7.4% in the control to 37.3-45.6% in the transformed lines, with FatB over-expression as the dominant trait. A twofold increase in 16:0 was observed in seed polar lipids. The melting point of oil from mature seeds was increased from -10 °C in DH12075 to 15 °C in the line with the highest saturated fatty acid content. TAG composition showed a shift from predominantly C54 TAG to C50 and C52 TAGs enriched in palmitic acid. Seedling establishment at low temperature was compromised in lines with high saturated fatty acid content. Results suggested that transcript encoding stearoyl-ACP desaturase in developing B. napus seeds is present in considerable excess of the level required for efficient desaturation of 18:0.
Keywords: Brassica napus; saturated fatty acid; FatB; stearoyl-acyl carrier protein desaturase; artificial microRNAs; palmitic acid

On the dielectric behavior of annealed plasma sprayed forsterite and alumina coatings - Lamarre, Jean-Michel; Cojocaru, Cristian V.; Legoux, Jean-Gabriel; National Research Council Canada (Proceedings of the International Thermal Spray Conference 2014 (ITSC), 2014)
Atmospheric plasma spray (APS) is an efficient technique for depositing high performance dielectric coatings at a low cost, with high deposition rate and on complex-shaped parts. Due to its availability, low price, ease to spray and good dielectric properties, alumina (Al2O3) is a very common choice of material for insulating applications. However, the coefficient of thermal expansion (CTE) of alumina does not represent the best match for the CTE of most metallic substrates hence alternative high CTE ceramic materials are of interest. We report on the microstructural and electrical properties of a dense high CTE forsterite (Mg2SiO4) coating deposited by APS. Annealed forsterite coatings' microstructure and dielectric properties are compared to that of annealed alumina coatings. The ceramics' electrical properties were evaluated by performing impedance measurements on as-sprayed coatings and coatings exposed to different annealing temperatures. We show that both materials exhibit important degradation after exposure to a threshold temperature. An equivalent electrical model is used to extract relevant coating properties such as resistivity and dielectric constant. The coating electrical degradation mechanisms are discussed.

Different cold spray deposition strategies : single- and multi-layers to repair aluminium alloy components - Rech, Silvano; Trentin, Andrea; Vezzù, Simone; Vedelago, Enrico; Legoux, Jean-Gabriel; Irissou, Éric (Journal of Thermal Spray Technology, 2014)
Cold spraying is increasingly being used for reconstruction or repair of damaged aluminium alloy components, especially in the aviation industry. Both thin (<0.5 mm) and thick (up to 1 cm) coatings are necessary to achieve dimensional recovery of such components. Thin and above all thick coatings can be deposited in a single pass (single layer) or in several passes (multi-pass), resulting in different thermal and stress effects in the component and the coating itself. The thermal input, the amount and type of residual stresses and the porosity affect various characteristics such as adhesion, crack propagation and mechanical properties of the coating. In this study, two sets (single- and multi-pass) of aluminium alloy (AA6061) coatings with different thicknesses (0.5 mm to 2 mm) were deposited onto AA6061 substrates and compared using metallographic and fractographic analyses, four-point bending testing, residual stress analysis and Vickers microhardness indentation. Finally, the coating adhesion and cohesion were measured using the standard ASTM-C633 adhesion test and tubular coating tensile test. This study demonstrates that the single-layer strategy results in greater adhesion and lower porosity, while multilayer coatings have higher elastic modulus. Independent of the strategy, the compressive residual stress decreases as a function of coating thickness.
Keywords: aircraft; feedstock; processing; testing

Distinguishing vaccinium species by chemical fingerprinting based on NMR spectra, validated with spectra collected in different laboratories - Markus, M.A.; Ferrier, J.; Luchsinger, S.M.; Yuk, J.; Cuerrier, A.; Balick, M.J.; Hicks, J.M.; Killday, K.B.; Kirby, C.W.; Berrue, F.; Kerr, R.G.; Knagge, K.; et al. (Planta Medica, 2014)
A method was developed to distinguish Vaccinium species based on leaf extracts using nuclear magnetic resonance spectroscopy. Reference spectra were measured on leaf extracts from several species, including lowbush blueberry (Vaccinium angustifolium), oval leaf huckleberry (Vaccinium ovalifolium), and cranberry (Vaccinium macrocarpon). Using principal component analysis, these leaf extracts were resolved in the scores plot. Analysis of variance statistical tests demonstrated that the three groups differ significantly on PC2, establishing that the three species can be distinguished by nuclear magnetic resonance. Soft independent modeling of class analogies models for each species also showed discrimination between species. To demonstrate the robustness of nuclear magnetic resonance spectroscopy for botanical identification, spectra of a sample of lowbush blueberry leaf extract were measured at five different sites, with different field strengths (600 versus 700MHz), different probe types (cryogenic versus room temperature probes), different sample diameters (1.7mm versus 5mm), and different consoles (Avance I versus Avance III). Each laboratory independently demonstrated the linearity of their NMR measurements by acquiring a standard curve for chlorogenic acid (R2=0.9782 to 0.9998). Spectra acquired on different spectrometers at different sites classifed into the expected group for the Vaccinium spp., confirming the utility of the method to distinguish Vaccinium species and demonstrating nuclear magnetic resonance fingerprinting for material validation of a natural health product.
Keywords: caffeic acid; chlorogenic acid; quinic acid; article; cranberry; magnetic field; nonhuman; nuclear magnetic resonance; nuclear magnetic resonance spectroscopy; principal component analysis; species identification; Vaccinium; Vaccinium angustifolium; Vaccinium ovalifolium

Exploring GLIMPSE bubble N107: Multiwavelength observations and simulations - Sidorin, V.; Douglas, K.A.; Palouš, J.; Wünsch, R.; Ehlerová, S. (Astronomy and Astrophysics, 2014)
Keywords: H II regions; ISM : clouds; Ism: bubbles; ISM: supernova remnants

Nanometer-scale Sn coatings improve the performance of silicon nanowire LIB anodes - Kohandehghan, A.; Cui, K.; Kupsta, M.; Memarzadeh, E.; Kalisvaart, P.; Mitlin, D. (Journal of Materials Chemistry A, 2014)
We demonstrate that a thin partially dewetted coating of Sn will improve the cycling performance of silicon nanowire (SiNWs) lithium ion battery (LIB) anodes. The optimum architecture 3Sn/SiNWs (i.e. a Sn layer with an average film thickness of a 3 nm covering the nanowire) maintained a reversible capacity of 1865 mA h g-1 after 100 cycles at a rate of 0.1 C. This is almost double of the baseline uncoated SiNWs, where the reversible capacity after 100 cycles was 1046 mA h g-1 (∼78% improvement). The 1Sn/SiNWs and 3Sn/SiNWs electrodes demonstrated much improved cycling coulombic efficiency, with >99% vs. 94-98% for the baseline. At a high current density of 5 C, these nanocomposite offered 2× the capacity retention of bare SiNWs (∼20 vs. ∼10% of 0.1 C capacity). It is demonstrated that the Sn coating both lithiates and delithiates at a higher voltage than Si and thus imparts a compressive stress around the nanowires. This confines their radial expansion in favor of longitudinal, and reduces the well-known failure mode by lithiation-induced nanowire stranding and fracture. TOF-SIMS analysis on the post-cycled delithiated specimens shows enhanced Li signal near the current collector due to accelerated SEI formation at the interface. FIB demonstrates concurrent en-masse delamination of SEI agglomerated sections of the nanowires from the current collector. Both of these deleterious effects are lessened by the presence of the Sn coatings. © 2014 the Partner Organisations.

Calcium-43 chemical shift and electric field gradient tensor interplay: A sensitive probe of structure, polymorphism, and hydration - Widdifield, C.M.; Moudrakovski, I.; Bryce, D.L. (Physical Chemistry Chemical Physics, 2014)
Calcium is the 5th most abundant element on earth, and is found in numerous biological tissues, proteins, materials, and increasingly in catalysts. However, due to a number of unfavourable nuclear properties, such as a low magnetogyric ratio, very low natural abundance, and its nuclear electric quadrupole moment, development of solid-state 43Ca NMR has been constrained relative to similar nuclides. In this study, 12 commonly-available calcium compounds are analyzed via43Ca solid-state NMR and the information which may be obtained by the measurement of both the 43Ca electric field gradient (EFG) and chemical shift tensors (the latter of which are extremely rare with only a handful of literature examples) is discussed. Combined with density functional theory (DFT) computations, this 'tensor interplay' is, for the first time for 43Ca, illustrated to be diagnostic in distinguishing polymorphs (e.g., calcium formate), and the degree of hydration (e.g., CaCl2·2H2O and calcium tartrate tetrahydrate). For Ca(OH)2, we outline the first example of 1H to 43Ca cross-polarization on a sample at natural abundance in 43Ca. Using prior knowledge of the relationship between the isotropic calcium chemical shift and the calcium quadrupolar coupling constant (CQ) with coordination number, we postulate the coordination number in a sample of calcium levulinate dihydrate, which does not have a known crystal structure. Natural samples of CaCO3 (aragonite polymorph) are used to show that the synthetic structure is present in nature. Gauge-including projector augmented-wave (GIPAW) DFT computations using accepted crystal structures for many of these systems generally result in calculated NMR tensor parameters which are in very good agreement with the experimental observations. This combination of 43Ca NMR measurements with GIPAW DFT ultimately allows us to establish clear correlations between various solid-state 43Ca NMR observables and selected structural parameters, such as unit cell dimensions and average Ca-O bond distances. © 2014 The Owner Societies.

Detection of high-energy compounds using photoluminescent silicon nanocrystal paper based sensors - Gonzalez, Christina M.; Iqbal, Muhammad; Dasog, Mita; Piercey, Davin G.; Lockwood, Ross; Klapötke, Thomas M.; Veinot, Jonathan G.C. (Nanoscale, 2014)
Luminescent silicon nanocrystals (Si-NCs) surface functionalized with dodecyl groups were exposed to solutions of nitroaromatic compounds including nitrobenzene, nitrotoluene, and dinitrotoluene. It was found that Si-NC luminescence was quenched upon exposure to nitroaromatics via an electron transfer mechanism as indicated by Stern-Volmer analysis. This quenching was exploited and a straightforward paper-based Si-NC sensor was developed. This paper motif was found to be sensitive to solution, vapor, and solid phase nitroaromatics, as well as solution borne RDX and PETN. © 2014 The Royal Society of Chemistry.

Colossal pseudocapacitance in a high functionality-high surface area carbon anode doubles the energy of an asymmetric supercapacitor - Li, Z.; Xu, Z.; Wang, H.; Ding, J.; Zahiri, B.; Holt, C.M.B.; Tan, X.; Mitlin, D. (Energy and Environmental Science, 2014)
Here we demonstrate a facile template-free synthesis route to create macroscopically monolithic carbons that are both highly nitrogen rich (4.1-7.6 wt%) and highly microporous (SA up to 1405 m2 g-1, 88 vol% micropores). While such materials, which are derived from common chicken egg whites, are expected to be useful in a variety of applications, they are extremely promising for electrochemical capacitors based on aqueous electrolytes. The Highly Functionalized Activated Carbons (HFACs) demonstrate a specific capacitance of >550 F g-1 at 0.25 A g-1 and >350 F g-1 at 10 A g-1 in their optimized state. These are among the highest values reported in the literature for carbon-based electrodes, including for systems such as templated carbons and doped graphene. We show that HFACs serve as ideal negative electrodes in asymmetric supercapacitors, where historically the specific capacitance of the oxide-based positive electrode was mismatched with the much lower specific capacitance of the opposing AC. An asymmetric cell employing HFACs demonstrates a 2× higher specific energy and a 4× higher volumetric energy density as compared to the one employing a high surface area commercial AC. With 3.5 mg cm-2 of HFAC opposing 5.0 mg cm-2 of NiCo 2O4/graphene, specific energies (active mass normalized) of 48 W h kg-1 at 230 W kg-1 and 28 W h kg-1 at 1900 W kg-1 are achieved. The asymmetric cell performance is among the best in the literature for hybrid aqueous systems, and actually rivals cells operating with a much wider voltage window in organic electrolytes. This journal is © 2014 the Partner Organisations.

Rechargeable batteries with gigh energy storage activated by in-situ induced fluorination of carbon nanotube cathode - Cui, X.; Chen, J.; Wang, T.; Chen, W. (Scientific Reports, 2014)
High performance rechargeable batteries are urgently demanded for future energy storage systems. Here, we adopted a lithium-carbon battery configuration. Instead of using carbon materials as the surface provider for lithium-ion adsorption and desorption, we realized induced fluorination of carbon nanotube array (CNTA) paper cathodes, with the source of fluoride ions from electrolytes, by an in-situ electrochemical induction process. The induced fluorination of CNTA papers activated the reversible fluorination/ defluorination reactions and lithium-ion storage/release at the CNTA paper cathodes, resulting in a dual-storage mechanism. The rechargeable battery with this dual-storage mechanism demonstrated ab maximum discharging capacity of 2174 mAh g carbon -1 and a specific energy of 4113 Wh kg carbon -1 with good cycling performance.

Deconvoluting the mechanism of microwave annealing of block copolymer thin films - Jin, C.; Murphy, J.N.; Harris, K.D.; Buriak, J.M. (ACS Nano, 2014)
The self-assembly of block copolymer (BCP) thin films is a versatile method for producing periodic nanoscale patterns with a variety of shapes. The key to attaining a desired pattern or structure is the annealing step undertaken to facilitate the reorganization of nanoscale phase-segregated domains of the BCP on a surface. Annealing BCPs on silicon substrates using a microwave oven has been shown to be very fast (seconds to minutes), both with and without contributions from solvent vapor. The mechanism of the microwave annealing process remains, however, unclear. This work endeavors to uncover the key steps that take place during microwave annealing, which enable the self-assembly process to proceed. Through the use of in situ temperature monitoring with a fiber optic temperature probe in direct contact with the sample, we have demonstrated that the silicon substrate on which the BCP film is cast is the dominant source of heating if the doping of the silicon wafer is sufficiently low. Surface temperatures as high as 240°C are reached in under 1 min for lightly doped, high resistivity silicon wafers (n- or p-type). The influence of doping, sample size, and BCP composition was analyzed to rule out other possible mechanisms. In situ temperature monitoring of various polymer samples (PS, P2VP, PMMA, and the BCPs used here) showed that the polymers do not heat to any significant extent on their own with microwave irradiation of this frequency (2.45 GHz) and power (∼600 W). It was demonstrated that BCP annealing can be effectively carried out in 60 s on non-microwave-responsive substrates, such as highly doped silicon, indium tin oxide (ITO)-coated glass, glass, and Kapton, by placing a piece of high resistivity silicon wafer in contact with the sample-in this configuration, the silicon wafer is termed the heating element. Annealing and self-assembly of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) and polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) BCPs into horizontal cylinder structures were shown to take place in under 1 min, using a silicon wafer heating element, in a household microwave oven. Defect densities were calculated and were shown to decrease with higher maximum obtained temperatures. Conflicting results in the literature regarding BCP annealing with microwave are explained in light of the results obtained in this study. © Published 2014 by the American Chemical Society.
Keywords: Block copolymers; Defect density; Microwave irradiation; Self assembly; Thin films; patterning; Thermal-annealing

Anodes for sodium ion batteries based on tin-germanium-Antimony alloys - Farbod, B.; Cui, K.; Kalisvaart, W.P.; Kupsta, M.; Zahiri, B.; Kohandehghan, A.; Lotfabad, E.M.; Li, Z.; Luber, E.J.; Mitlin, D. (ACS Nano, 2014)
Here we provide the first report on several compositions of ternary Sn-Ge-Sb thin film alloys for application as sodium ion battery (aka NIB, NaB or SIB) anodes, employing Sn50Ge50, Sb50Ge50, and pure Sn, Ge, Sb as baselines. Sn33Ge33Sb33, Sn50Ge25Sb25, Sn60Ge20Sb20, and Sn50Ge50 all demonstrate promising electrochemical behavior, with Sn50Ge25Sb25 being the best overall. This alloy has an initial reversible specific capacity of 833 mAhg-1 (at 85 mAg-1) and 662 mAhg-1 after 50 charge-discharge cycles. Sn50Ge25Sb25 also shows excellent rate capability, displaying a stable capacity of 381 mAhg-1 at a current density of 8500 mAg-1 (~10C). A survey of published literature indicates that 833 mAhg-1 is among the highest reversible capacities reported for a Sn-based NIB anode, while 381 mAhg-1 represents the optimum fast charge value. HRTEM shows that Sn50Ge25Sb25 is a composite of 10-15 nm Sn and Sn-Alloyed Ge nanocrystallites that are densely dispersed within an amorphous matrix. Comparing the microstructures of alloys where the capacity significantly exceeds the rule of mixtures prediction to those where it does not leads us to hypothesize that this new phenomenon originates from the Ge(Sn) that is able to sodiate beyond the 1:1 Na:Ge ratio reported for the pure element. Combined TOF-SIMS, EELS TEM, and FIB analysis demonstrates substantial Na segregation within the film near the current collector interface that is present as early as the second discharge, followed by cycling-induced delamination from the current collector. © Published 2014 by the American Chemical Society.
Keywords: Anodes; Sn; Sb; Ge; Thin films; LIB; Lithium-ion battery; NaB; NIB; SIB; Sodium ion batteries

Directed branch growth in aligned nanowire arrays - Beaudry, A.L.; Laforge, J.M.; Tucker, R.T.; Sorge, J.B.; Adamski, N.L.; Li, P.; Taschuk, M.T.; Brett, M.J. (Nano Letters, 2014)
Branch growth is directed along two, three, or four in-plane directions in vertically aligned nanowire arrays using vapor-liquid-solid glancing angle deposition (VLS-GLAD) flux engineering. In this work, a dynamically controlled collimated vapor flux guides branch placement during the self-catalyzed epitaxial growth of branched indium tin oxide nanowire arrays. The flux is positioned to grow branches on select nanowire facets, enabling fabrication of aligned nanotree arrays with L-, T-, or X-branching. In addition, a flux motion algorithm is designed to selectively elongate branches along one in-plane axis. Nanotrees are found to be aligned across large areas by X-ray diffraction pole figure analysis and through branch length and orientation measurements collected over 140 μm2 from scanning electron microscopy images for each array. The pathway to guided assembly of nanowire architectures with controlled interconnectivity in three-dimensions using VLS-GLAD is discussed. © 2014 American Chemical Society.
Keywords: Branched nanowires; Glancing Angle Deposition; Indium tin oxide; Nanotrees; Vapor-liquid-solid; Epitaxy