Merging recent and historic spectra of ε Aurigae: Properties of the system's components, and discovery of a mass transfer stream - Griffin, R. Elizabeth; Stencel, Robert E. (Publications of the Astronomical Society of the Pacific, 2013)
This study of new CCD spectra of ε Aur recorded in the blue and near-UV during the 2010 eclipse has been reinforced and extended by the inclusion of some 130 digitized historic spectra from MountWilson (dating back to the 1930s) and from the DAO (dating from 1971). The precise repetition of disk-related spectral-line changes during three successive eclipses indicates that the structure of the disk does not alter appreciably on a time-scale of a least a century.We deduce that the disk has an extensive but optically thin outer layer, and a flat structure that is tilted near to edge-on. We discover that it is receiving from the supergiant a very confined stream of material that is enriched in rare-earth elements. The stream has an approach velocity very similar to the projected rotational velocity of the F star; it has an extremely small velocity dispersion, and is only visible between specific egress phases. We surmise that the F star is a horizontal-branch star though its own photosphere appears, on average, to have a solar composition.We also uncover variable broad emission in the system and find a possible correlation with the F-star's Cepheid-like ~67-day pulsations that cause its photometric variations. © 2013. The Astronomical Society of the Pacific. All rights reserved.

Kuiper belt occultation predictions - Fraser, Wesley C.; Gwyn, Stephen; Trujillo, Chad; Stephens, Andrew W.; Kavelaars, J. J.; Brown, Michael E.; Bianco, Federica B.; Boyle, Richard P.; Brucker, Melissa J.; Hetherington, Nathan; Joner, Michael; Keel, William C.; et al. (Publications of the Astronomical Society of the Pacific, 2013)
Here we present observations of seven large Kuiper Belt objects. From these observations, weextract a point source catalog with ~0:01″ precision, and astrometry of our target Kuiper Belt objects with0.04-0.08″ precision within that catalog. We have developed a new technique to predict the future occurrenceof stellar occultations by Kuiper Belt objects. The technique makes use of a maximum likelihood approach whichdetermines the best-fit adjustment to cataloged orbital elements of an object. Using simulations of a theoreticalobject, we discuss the merits and weaknesses of this technique compared to the commonly adopted ephemeris offsetapproach. We demonstrate that both methods suffer from separate weaknesses, and thus together provide a fairassessment of the true uncertainty in a particular prediction. We present occultation predictions made by both methodsfor the seven tracked objects, with dates as late as 2015. Finally, we discuss observations of three separate closepassages of Quaoar to field stars, which reveal the accuracy of the element adjustment approach, and which alsodemonstrate the necessity of considering the uncertainty in stellar position when assessing potential occultations. © 2013. The Astronomical Society of the Pacific. All rights reserved.

GASKAP-the galactic ASKAP survey - Dickey, John M.; McClure-Griffiths, Naomi; Gibson, Steven J.; Gómez, José F.; Imai, Hiroshi; Jones, Paul; Stanimirović, Snežana; Van Loon, Jacco Th.; Walsh, Andrew; Alberdi, A.; Anglada, G.; Uscanga, L.; et al. (Publications of the Astronomical Society of Australia, 2013)
A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40°, spanning longitudes 167° through 360°to 79 at b = 0°, plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg2. The brightness temperature sensitivity will be very good, typically σT≃ 1 K at resolution 30 arcsec and 1 km s -1. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream. © 2013 Astronomical Society of Australia.

Science with the Murchison Widefield Array - Bowman, Judd D.; Cairns, Iver; Kaplan, David L.; Murphy, Tara; Oberoi, Divya; Staveley-Smith, Lister; Arcus, Wayne; Barnes, David G.; Bernardi, Gianni; Briggs, Frank H.; Brown, Shea; Bunton, John D.; et al. (Publications of the Astronomical Society of Australia, 2013)
Significant new opportunities for astrophysics and cosmology have been identified at low radio frequencies. The Murchison Widefield Array is the first telescope in the southern hemisphere designed specifically to explore the low-frequency astronomical sky between 80 and 300 MHz with arcminute angular resolution and high survey efficiency. The telescope will enable new advances along four key science themes, including searching for redshifted 21-cm emission from the EoR in the early Universe; Galactic and extragalactic all-sky southern hemisphere surveys; time-domain astrophysics; and solar, heliospheric, and ionospheric science and space weather. The Murchison Widefield Array is located in Western Australia at the site of the planned Square Kilometre Array (SKA) low-band telescope and is the only low-frequency SKA precursor facility. In this paper, we review the performance properties of the Murchison Widefield Array and describe its primary scientific objectives. © 2013 Astronomical Society of Australia.

Activationless charge transport across 4.5 to 22 nm in molecular electronic junctions - Yan, Haijun; Bergren, Adam Johan; McCreery, Richard; Della Rocca, Maria Luisa; Martin, Pascal; Lafarge, Philippe; Lacroix, Jean Christophe (Proceedings of the National Academy of Sciences of the United States of America, 2013)
In this work, we bridge the gap between short-range tunneling in molecular junctions and activated hopping in bulk organic films, and greatly extend the distance range of charge transport in molecular electronic devices. Three distinct transport mechanisms were observed for 4.5-22-nm-thick oligo(thiophene) layers between carbon contacts, with tunneling operative when d< 8 nm, activated hoppingwhen d> 16nmfor high temperatures and lowbias, and a third mechanism consistent with field-induced ionization of highest occupiedmolecular orbitals or interface states to generate charge carriers when d = 8-22 nm. Transport in the 8-22-nm range is weakly temperature dependent, with a field-dependent activation barrier that becomes negligible at moderate bias. We thus report here a unique, activationless transport mechanism, operative over 8-22-nm distanceswithout involving hopping,which severely limits carriermobility and device lifetime in organic semiconductors. Charge transport in molecular electronic junctions can thus be effective for transport distances significantly greater than the 1-5 nm associated with quantum-mechanical tunneling.
Keywords: charge transport; electric field; electricity; high temperature; ionization; semiconductor; Carbon; Electronics; Hot Temperature; Ion Exchange; Nanotechnology; Quantum Theory; Semiconductors

Photonic crystal split-beam nanocavities for torsional optomechanics - Wu, Marcelo; Hryciw, Aaron C.; Khanaliloo, Behzad; Healey, Chris; Freeman, Mark R.; Davis, John P.; Barclay, Paul E. (Laser Resonators, Microresonators, and Beam Control XV, 2013)
Keywords: Environmental stimuli; Integrated device; Magnetometry; Mechanical resonators; Nanomechanical resonators; Opto-mechanics; Photonic crystal nanocavity; Silicon photonics; Embedded systems; Laser resonators; Magnetometers; Nanomagnetics; Nanophotonics; Nanotechnology; Optical fibers; Optical resonators; Photonics; Resonators; Photonic crystals

ESPRESSO APSU: simplify the life of pupil slicing - Conconi, P.; Riva, M.; Pepe, F.; Zerbi, F.M.; Cabral, A.; Cristiani, S.; Megevand, D.; Landoni, M.; Spanó, P. (Novel Optical Systems Design and Optimization XVI, 2013)
Keywords: Anamorphic; Cylindrical optics; Echelle spectrograph; Exo-planets; Optical components; Slit width; Very large telescope; Optimization; Systems analysis

Meta-modeling optimization of the cutting process during turning titanium metal matrix composites (Ti-MMCs) - Aramesh, M.; Shi, B.; Nassef, A. O.; Attia, H.; Balazinski, M.; Kishawy, H. A. (Procedia CIRP, 2013)
The Outstanding characteristics of titanium metal matrix composites (Ti-MMCs) have brought them up as promising materials in different industries, such as aerospace and biomedical. They exhibit high mechanical and physical properties, in addition to their low weight, high stiffness and high wear resistance. The presence of the ceramic reinforcements in a metallic matrix further contributes to these preferable properties. However, the high abrasive nature of the ceramic particles limits greatly the machinability of this class of material, as they induce significant tool wear and poor surface finish. In this study an attempt is made to find the optimum cutting conditions in terms of minimizing the tool wear and surface roughness during machining Ti-MMCs. Meta-modeling optimization in performed to achieve the goal. In this study the three independent parameters under consideration are the cutting speed, feed rate and the depth of cut. The response parameters are the surface roughness and the tool wear rate. The independent parameters are divided into a set of levels at which the experiments are conducted. At each experimental condition the two response parameters are measured. Kriging meta-modeling technique is used to fit a model to the response parameters in the multi-dimensional space. These models are used, in turn, within a multi-objective optimization algorithm to find the optimum cutting condition space. The above-mentioned algorithm is based on an evolutionary multi-objective search technique known as SPEA (Strength Pareto Evolutionary Algorithm). Copyright © 2013 Elsevier B.V.
Keywords: Experimental conditions; Mechanical and physical properties; Meta-modeling technique; MMCs; Multi-dimensional space; Strength pareto evolutionary algorithm; Titanium metal matrix composites; Tool wear; Algorithms; Machining centers; Multiobjective optimization; Surface roughness; Wear of materials

Nanopore analysis of wild-type and mutant prion protein (PrPC): single molecule discrimination and PrPC kinetics - Jetha, Nahid N.; Semenchenko, Valentyna; Wishart, David S.; Cashman, Neil R.; Marziali, Andre (PLoS ONE, 2013)
Prion diseases are fatal neurodegenerative diseases associated with the conversion of cellular prion protein (PrPC) in the central nervous system into the infectious isoform (PrPSc). The mechanics of conversion are almost entirely unknown, with understanding stymied by the lack of an atomic-level structure for PrPSc. A number of pathogenic PrPC mutants exist that are characterized by an increased propensity for conversion into PrPSc and that differ from wild-type by only a single amino-acid point mutation in their primary structure. These mutations are known to perturb the stability and conformational dynamics of the protein. Understanding of how this occurs may provide insight into the mechanism of PrPC conversion. In this work we sought to explore wild-type and pathogenic mutant prion protein structure and dynamics by analysis of the current fluctuations through an organic α-hemolysin nanometer-scale pore (nanopore) in which a single prion protein has been captured electrophoretically. In doing this, we find that wild-type and D178N mutant PrPC, (a PrPC mutant associated with both Fatal Familial Insomnia and Creutzfeldt-Jakob disease), exhibit easily distinguishable current signatures and kinetics inside the pore and we further demonstrate, with the use of Hidden Markov Model signal processing, accurate discrimination between these two proteins at the single molecule level based on the kinetics of a single PrPC capture event. Moreover, we present a four-state model to describe wild-type PrPC kinetics in the pore as a first step in our investigation on characterizing the differences in kinetics and conformational dynamics between wild-type and D178N mutant PrPC. These results demonstrate the potential of nanopore analysis for highly sensitive, real-time protein and small molecule detection based on single molecule kinetics inside a nanopore, and show the utility of this technique as an assay to probe differences in stability between wild-type and mutant prion proteins at the single molecule level. © 2013 Jetha et al.
Keywords: alpha hemolysin; asparagine; aspartic acid; prion protein; amino acid sequence; amino terminal sequence; complex formation; Creutzfeldt Jakob disease; fatal familial insomnia; molecular dynamics; nanoanalysis; point mutation; predictive value; protein conformation; protein stability; wild type; kinetics; nanopores; prion diseases; prions; protein conformation

The human urine metabolome - Bouatra, Souhaila; Aziat, Farid; Mandal, Rupasri; Guo, An Chi; Wilson, Michael R.; Knox, Craig; Bjorndahl, Trent C.; Krishnamurthy, Ramanarayan; Saleem, Fozia; Liu, Philip; Dame, Zerihun T.; Poelzer, Jenna; et al. (PLoS ONE, 2013)
Urine has long been a "favored" biofluid among metabolomics researchers. It is sterile, easy-to-obtain in large volumes, largely free from interfering proteins or lipids and chemically complex. However, this chemical complexity has also made urine a particularly difficult substrate to fully understand. As a biological waste material, urine typically contains metabolic breakdown products from a wide range of foods, drinks, drugs, environmental contaminants, endogenous waste metabolites and bacterial by-products. Many of these compounds are poorly characterized and poorly understood. In an effort to improve our understanding of this biofluid we have undertaken a comprehensive, quantitative, metabolome-wide characterization of human urine. This involved both computer-aided literature mining and comprehensive, quantitative experimental assessment/validation. The experimental portion employed NMR spectroscopy, gas chromatography mass spectrometry (GC-MS), direct flow injection mass spectrometry (DFI/LC-MS/MS), inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) experiments performed on multiple human urine samples. This multi-platform metabolomic analysis allowed us to identify 445 and quantify 378 unique urine metabolites or metabolite species. The different analytical platforms were able to identify (quantify) a total of: 209 (209) by NMR, 179 (85) by GC-MS, 127 (127) by DFI/LC-MS/MS, 40 (40) by ICP-MS and 10 (10) by HPLC. Our use of multiple metabolomics platforms and technologies allowed us to identify several previously unknown urine metabolites and to substantially enhance the level of metabolome coverage. It also allowed us to critically assess the relative strengths and weaknesses of different platforms or technologies. The literature review led to the identification and annotation of another 2206 urinary compounds and was used to help guide the subsequent experimental studies. An online database containing the complete set of 2651 confirmed human urine metabolite species, their structures (3079 in total), concentrations, related literature references and links to their known disease associations are freely available at http://www.urinemetabolome.ca. © 2013 Bouatra et al.
Keywords: direct flow injection mass spectrometry; high performance liquid chromatography; mass fragmentography; mass spectrometry; metabolite; metabolome; nuclear magnetic resonance spectroscopy; urinalysis; urine level

Two-dimensional incommensurate and three-dimensional commensurate magnetic order and fluctuations in La2-xBaxCuO4 - Wagman, J. J.; Van Gastel, G.; Ross, K. A.; Yamani, Z.; Zhao, Y.; Qiu, Y.; Copley, J. R. D.; Kallin, A. B.; Mazurek, E.; Carlo, J. P.; Dabkowska, H. A.; Gaulin, B. D. (Physical Review B - Condensed Matter and Materials Physics, 2013)
We present neutron-scattering measurements on single crystals of lightly doped La2-xBaxCuO4, with 0≤x≤0.035. These reveal the evolution of the magnetism in this prototypical doped Mott insulator from a three-dimensional (3D) commensurate (C) antiferromagnetic ground state, which orders at a relatively high TN, to a two-dimensional (2D) incommensurate (IC) ground state with finite-ranged static correlations, which appear below a relatively low effective TN. At low temperatures, the 2D IC magnetism coexists with the 3D C magnetism for doping concentrations as low as ∼0.0125. We find no signal of a 3D C magnetic ground state by x∼0.025, consistent with the upper limit of x∼0.02 observed in the sister family of doped Mott insulators, La2-xSrxCuO 4. The 2D IC ground states observed for 0.0125≤x≤0.035 are diagonal, and are rotated by 45 degrees within the orthorhombic basal plane compared with those previously reported for samples with superconducting ground states: La2-xBaxCuO4, with 0.05≤x≤0.095. We construct a phase diagram based solely on magnetic order-parameter measurements, which displays much of the complexity of standard high-temperature superconductivity phase diagrams discussed in the literature. Analysis of high-energy resolution inelastic neutron scattering at moderately low temperatures shows a progressive depletion of the very low-energy dynamic magnetic susceptibility as x increases from 0.0125 to 0.035. This low-energy, dynamic susceptibility falls off with increasing temperature on a scale much higher than the effective 2D IC TN appropriate to these materials. Appreciable dynamic 2D IC magnetic fluctuations inhabit much of the "pseudogap" regime of the phase diagram. ©2013 American Physical Society.

Single-molecule assays for investigating protein misfolding and aggregation - Hoffmann, Armin; Neupane, Krishna; Woodside, Michael T. (Physical Chemistry Chemical Physics, 2013)
Protein misfolding and aggregation are relevant to many fields. Recently, their investigation has experienced a revival as a central topic in the research of numerous human diseases, including Parkinson's and Alzheimer's. Much has been learned from ensemble biochemical approaches, but the inherently heterogeneous nature of the underlying processes has obscured many important details. Single-molecule techniques offer unique capabilities to study heterogeneous systems, while providing high temporal and structural resolution to characterize them. In this Perspective, we give an overview of the single-molecule assays that have been applied to protein misfolding and aggregation, which are mainly based on fluorescence and force spectroscopy. We describe some of the technical challenges involved in studying aggregation at the single-molecule level and discuss what has been learned about aggregation mechanisms from the different approaches. © 2013 the Owner Societies.
Keywords: atomic force microscopy; metabolism; protein folding; protein multimerization; spectrofluorometry; Amyloid; Microscopy, Atomic Force; Protein Folding; Protein Multimerization; Proteins; Spectrometry, Fluorescence

Performance of conventional and dispersion-corrected density-functional theory methods for hydrogen bonding interaction energies - DiLabio, Gino A.; Johnson, Erin R.; Otero-de-la-Roza, Alberto (Physical Chemistry Chemical Physics, 2013)
The approximate CCSD(T)/CBS binding energies for the set of 23 hydrogen-bonded dimers (HB23) of the S66 set reported by Řezá č et al. (J. Chem. Theory Comput. 2011, 7, 2427-2438) were expected to be under-estimated based on the known under-binding tendency of the counterpoise correction combined with small basis sets. In this work, we present binding energies for the HB23 set of dimers obtained using a composite approach recently described by Mackie and DiLabio (J. Chem. Phys. 2011, 135, 134318) that averages the counterpoise- and non-counterpoise-corrected energies, while utilizing standard approaches to obtain CCSD(T)/CBS-type energies. The binding energies for the HB23 set are revised upward by an average of 0.12 kcal mol-¹ and as much as 0.35 kcal mol-¹. We use these improved benchmark-level binding energies to evaluate the ability of pure, hybrid, long-range-corrected, and dispersion-corrected density-functional theory (DFT) methods to accurately predict the binding energies of hydrogen-bonded dimers. We find that, in general, the inclusion of dispersion into the DFT approach is required in order to obtain reasonable results for the HB23 set. We find that the dispersion-corrected DFT methods we tested produce results of variable quality, as measured by mean absolute deviation relative to the revised reference values we computed: B97D, 0.57 kcal mol-¹; B3LYP-D3, 0.44 kcal mol-¹; ωB97XD, 0.25 kcal mol-¹; LC-ωPBE-D3, 0.24 kcal mol-¹; M06-2X, 0.21 kcal mol-¹; B3LYP-DCP, 0.23 kcal mol-¹; B971-XDM, 0.18 kcal mol-¹. © the Owner Societies 2013.

ALD TiO2 coated silicon nanowires for lithium ion battery anodes with enhanced cycling stability and coulombic efficiency - Memarzadeh Lotfabad, Elmira; Kalisvaart, Pater; Cui, Kai; Kohandehghan, Alireza; Kupsta, Martin; Olsen, Brian; Mitlin, David (Physical Chemistry Chemical Physics, 2013)
We demonstrate that silicon nanowire (SiNW) Li-ion battery anodes that are conformally coated with TiO2 using atomic layer deposition (ALD) show a remarkable performance improvement. The coulombic efficiency is increased to ∼99%, among the highest ever reported for SiNWs, as compared to 95% for the baseline uncoated samples. The capacity retention after 100 cycles for the nanocomposite is twice as high as that of the baseline at 0.1 C (60% vs. 30%), and more than three times higher at 5 C (34% vs. 10%). We also demonstrate that the microstructure of the coatings is critically important for achieving this effect. Titanium dioxide coatings with an as-deposited anatase structure are nowhere near as effective as amorphous ones, the latter proving much more resistant to delamination from the SiNW core. We use TEM to demonstrate that upon lithiation the amorphous coating develops a highly dispersed nanostructure comprised of crystalline LiTiO2 and a secondary amorphous phase. Electron energy loss spectroscopy (EELS) combined with bulk and surface analytical techniques are employed to highlight the passivating effect of TiO2, which results in significantly fewer cycling-induced electrolyte decomposition products as compared to the bare nanowires. © 2013 The Owner Societies.

Thermodynamically destabilized hydride formation in "bulk" Mg-AlTi multilayers for hydrogen storage - Kalisvaart, Peter; Shalchi-Amirkhiz, Babak; Zahiri, Ramin; Zahiri, Benjamin; Tan, XueHai; Danaie, Mohsen; Botton, Gianluigi; Mitlin, David (Physical Chemistry Chemical Physics, 2013)
Thermodynamic destabilization of MgH2 formation through interfacial interactions in free-standing Mg-AlTi multilayers of overall "bulk" (0.5 μm) dimensions with a hydrogen capacity of up to 5.5 wt% is demonstrated. The interfacial energies of Mg-AlTi and Mg-Ti (examined as a baseline) are calculated to be 0.81 and 0.44 J m-2. The enhanced interfacial energy of AlTi opens the possibility of creating ultrathin alloy interlayers that provide further thermodynamic improvements in metal hydrides. © 2013 The Owner Societies.

Quantum mechanical treatment of binding energy between DNA nucleobases and carbon nanotube: A DFT analysis - Chehel Amirani, Morteza; Tang, Tian; Cuervo, Javier (Physica E: Low-Dimensional Systems and Nanostructures, 2013)
The interactions between DNA and carbon nanotubes (CNTs) have been widely studied in recent years. The binding process of DNA with CNT as well as the electronic properties of DNA/CNT hybrids constitutes an interesting yet complicated problem. The binding energy (BE) of the hybridization is one of the most extensively studied parameters for the problem. In this work, density functional theory (DFT) was used to perform geometry optimization of neutral nucleobases including adenine, cytosine, guanine and thymine absorbed on a zigzag (7,0) single-walled CNT and to evaluate the basis set superposition error corrected BE of the optimized configuration. All DFT calculations were performed using the M05-2X functional. The 6-31G(d) basis set was used for the optimization step and single point energy calculations were done using the 6-31G(d,p) basis set. For each nucleobase, we examined the influence of the initial configuration (IC) on the BE value. In particular, we considered 24 different ICs for each nucleobase, and each IC was subjected to an independent optimization and BE calculation. Our results showed that different ICs result in very different BE values and can even change the order of the BE corresponding to different nucleobases. The difference in the BE for a particular nucleobase caused by changes in its IC can be comparable to the difference in the BE between different nucleobases at the same initial position relative to the CNT. This provides an explanation for the discrepancies that exist in the literature on the nucleobase/CNT BE, and suggests that the potential energy surface between the nucleobases and the CNT can have many local minima and care should be exercised in the calculation and interpretation of the BE. © 2013 Elsevier B.V.
Keywords: Basis set superposition errors; DFT; Geometry optimization; Initial configuration; Nucleobases; Optimized configuration; Quantum-mechanical treatments; Single-point energy; Binding energy; Density functional theory; DNA; Electronic properties; Optimization; Quantum chemistry; Quantum theory; Carbon nanotubes

Bioactive rosette nanotubes for bone tissue engineering and drug delivery - Beingessner, Rachel L.; Alsbaiee, Alaaeddun; Singh, Baljit; Webster, Thomas J.; Fenniri, Hicham (Peptide Materials: From Nanostructures to Applications, 2013)
This chapter describes novel bio-inspired nanotubular architectures called rosette nanotubes (RNTs), which are self-assembled in water from a guanine-cytosine (the Gn-ary logical andC motif) hybrid molecule. In the first part of the chapter, the design, synthesis and chemical functionalization of RNTs with amino acid residues, peptides and other organic and inorganic moieties are highlighted. Their stability and physical properties are next examined, followed by in vivo and in vitro toxicity and biocompatibility studies. Finally, RNT applications in bone tissue engineering and in drug delivery are described. In the case of the former, this includes RNTs as 2D coatings on Ti implant materials, as well as their incorporation within currently used pHEMA hydrogels for enhanced bone cell adhesion and growth. © 2013 John Wiley & Sons, Ltd.
Keywords: rosette nanotubes; guanine-cytosine motif; self-assembly; bioactive peptides; bone tissue engineering; titanium implant materials; osteoblast; hydrogels; drug delivery

Optical design of split-beam photonic crystal nanocavities - Hryciw, Aaron C.; Barclay, Paul E. (Optics Letters, 2013)
We design high-quality-factor photonic crystal nanobeam cavities formed by two mechanically isolated cantilevers. These "split-beam" cavities have a physical gap at the center, allowing mechanical excitations of one or both of the cavity halves. They are designed by analyzing the optical band structures and mode profiles of waveguides perforated by elliptical holes and rectangular gaps and are predicted to support optical resonances with quality factors exceeding 10⁶ at wavelengths of ∼1.6 μm.
Keywords: Elliptical holes; High quality factors; Mechanical excitations; Optical band structure; Optical resonance; Photonic crystal nanobeam; Photonic crystal nanocavities; Quality factors; Optical design; Quantum optics; Photonic crystals

Photothermal nonlinearity and optical bistability in a graphene-silicon waveguide resonator - Horvath, Cameron; Bachman, Daniel; Indoe, Rob; Van, Vien (Optics Letters, 2013)
We report observation of optical bistability and enhanced thermal nonlinearity in a graphene-silicon waveguide resonator. Photo-induced Joule heating in the graphene layer gives rise to a temperature increase in the silicon waveguide core and a corresponding thermo-optic shift in the resonance of the Fabry-Perot resonator. Measurement of the nonlinear resonance spectra showed a 9-fold increase in the effective thermal nonlinear index due to the graphene layer compared with a bare silicon waveguide. © 2013 Optical Society of America.
Keywords: Fabry-Perot resonators; Graphene layers; Nonlinear index; Nonlinear resonance; Silicon waveguide; Temperature increase; Thermal nonlinearities; Waveguide resonators; Resonators; Silicon; Waveguides; Graphene

Glancing angle deposited nanostructured film Fabry-Perot etalons for optical detection of ultrasound - Hajireza, Parsin; Krause, Kathleen; Brett, Michael; Zemp, Roger (Optics Express, 2013)
In this paper a new class of optical Fabry-Perot-based ultrasound detectors using low acoustic impedance glancing angle deposited (GLAD) films is demonstrated. GLAD is a single-step physical vapor-deposition (PVD) technique used to fabricate porous nanostructured thin films. Using titanium dioxide (TiO2), a transparent semiconductor with a high refractive index (n = 2.4), the GLAD technique can be employed to fabricate samples with tailored nano-porosity, refractive index periodicities, and high Q-factor reflectance spectra. The average acoustic impedance of the porous films is lower than bulk materials which will improve acoustic coupling, especially for high acoustic frequencies. For this work, two filters with high reflection in the C-band range and high transparency in the visible range (∼80%) using GLAD films were fabricated. A 23 μm Parylene C layer was sandwiched between these two GLAD films in order to form a GLAD Fabry Perot Interferometer (GLAD-FPI). A high speed tunable continuous wavelength C-band laser was focused at the FPI and the reflection was measured using a high speed photodiode. The ultrasound pressure modulated the optical thickness of the FPI and hence its reflectivity. The fabricated sensor was tested using a 10 MHz unfocused transducer. The ultrasound transducer was calibrated using a hydrophone. The minimum detectable acoustic pressure was measured as 80 ± 20 Pa and the -3dB bandwidth was measured to be 18 MHz. This ultra-sensitive sensor can be an alternative to piezoelectric ultrasound transducers for any techniques in which ultrasound waves need to be detected including ultrasonic and photoacoustic imaging modalities. We demonstrate our GLAD-FPI for photoacoustic signal detection in optical-resolution photoacoustic microscopy (OR-PAM). To the best of our knowledge, this is the first time that a FPI fabricated using the GLAD method has been used for ultrasensitive ultrasound detection. © 2013 Optical Society of America.
Keywords: High refractive index; Nanostructured thin film; Optical detection of ultrasound; Photo-acoustic imaging; Photoacoustic signals; Titanium dioxides (TiO2); Transparent semiconductor; Ultrasound transducers; Acoustic impedance; Deposits; Fabrication; Reflection; Refractive index; Sensors; Ultrasonic propagation; Ultrasonic scattering; Ultrasonic testing; Ultrasonic transducers; Ultrasonics; Vapors; Fabry-Perot interferometers

Design and fabrication of a planar PDMS transmission grating microspectrometer - Azmayesh-Fard, Seyed M.; Lam, Lawrence; Melnyk, Aaron; DeCorby, Ray G. (Optics Express, 2013)
We describe the monolithic integration of microfluidic channels, optical waveguides, a collimating lens and a curved focusing transmission grating in a single PDMS-based microsystem. All optical and fluidic components of the device were simultaneously formed in a single layer of high refractive index (n∼1.43) PDMS by soft lithography. Outer layers of lower-index (n∼1.41) PDMS were subsequently added to provide optical and fluidic confinement. Here, we focus on the design and characterization of the microspectrometer part, which employs a novel self-focusing strategy based on cylindrical facets, and exhibits resolution <10 nm in the visible wavelength range. The dispersive behavior of the grating was analyzed both experimentally and using numerical simulations, and the results are in good agreement with simplified analytical predictions. © 2013 Optical Society of America.
Keywords: Analytical predictions; Dispersive behaviors; Fluidic components; High refractive index; Microfluidic channel; Monolithic integration; Transmission gratings; Visible-wavelength range; Monolithic integrated circuits; Refractive index; Microchannels; baysilon; dimeticone; article; chemistry; electronics; equipment; equipment design; equipment failure; microfluidic analysis; optical instrumentation; refractometry; spectroscopy; Dimethylpolysiloxanes; Equipment Design; Equipment Failure Analysis; Lenses; Microfluidic Analytical Techniques; Miniaturization; Refractometry; Spectrum Analysis

Production of 70-nm Cr dots by laser-induced forward transfer - Sametoglu, Vahit; Sauer, Vincent T. K.; Tsui, Ying Y. (Optics Express, 2013)
The effect of donor film thickness and laser beam fluence on the size of laser-induced forward transfer (LIFT) spots is studied to achieve sub-100 nm features. A 130 fs, 800 nm laser is focused on ultrathin Cr films, and the transfer and ablation thresholds of these films at various thicknesses are determined. The minimum transfer spot size decreases with decreasing donor film thickness and incident laser fluence. Minimum LIFT spots of 70-450 nm diameter are obtained from films of 20-80 nm thickness, respectively. The 70 nm diameter transfer spots obtained from sputtered continuous films are the smallest to date. © 2013 Optical Society of America.
Keywords: Ablation thresholds; Continuous films; Incident laser; Laser-induced forward transfer; Production of; Spot sizes; Sub-100 nm; Ultra-thin; Film thickness; Mass transfer; Ultrathin films

Numerical hydrodynamic evaluation of propeller (with hub taper) and podded drive in azimuthing conditions - Shamsi, Reza; Ghassemi, Hassan; Molyneux, David; Liu, Pengfei (Ocean Engineering, 2013)
This paper aims to predict the hydrodynamic forces on a propeller with different hub taper angles and a podded drive unit in azimuthing conditions. In order to evaluate the propulsive performance of the podded drive system, a Reynolds-Averaged Navier Stokes (RANS) solver is employed. The method has been first verified by a single propeller with different hub taper angles. The performance curves of the propellers, obtained by numerical methods, have been compared to and validated with experimental results. In the next step, the method has been extended to the podded drive unit for both puller and pusher configurations. The yaw angles of the podded drives are set to vary from -30° to +30° with 5° increments. The propulsive characteristics, including the torque and thrust of the propeller, the axial force, and the side force of the unit are presented as functions of the advance velocity ratio and yaw angle. Computational results are compared to the available experimental data. Finally, it is shown there is good agreement between the experimental measurements and the results of the present numerical method. © 2013 Elsevier Ltd. All rights reserved.
Keywords: RANS method; Hub taper; Podded drive; Azimuthing condition; Hydrodynamic forces

Electron irradiation damage and color centers of MgO nanocube - Zhang, Huai-Ruo; Egerton, Ray; Malac, Marek (Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, 2013)
Magnesium oxide (MgO) has been of interest for several decades as a promising tunable broadband laser due to its vacancy defects (color centers). In this work we introduced color centers into MgO nanocube by electron irradiation in a transmission electron microscope (TEM). Square nano-holes were formed from the electron-exit face using 100 and 300 keV electrons, and a broad O-vacancy (color-center) absorption peak around 4.1-6.6 eV was observed by valence-electron energy-loss spectroscopy (VEELS). We investigated the mechanism of MgO damage by high-energy electron beams. The hole formation is believed to involve a mixed removal of diatomic MgO molecules as well as Mg and O species in stoichiometric proportion. Observations using high-resolution transmission electron microscopy (HRTEM) and VEELS suggest that bulk O-vacancies are generated near the electron-exit face, due to the forward momentum transferred from fast-electron collisions and the Coulomb attraction of negative O-ions by the positively charged MgO surface. © 2013 Elsevier B.V. All rights reserved.
Keywords: Broad-band lasers; Coulomb attraction; Electron irradiation damage; Energy-loss spectroscopy; High energy electron beams; MgO; Positively charged; Color centers; Electron energy loss spectroscopy; Electrons; Transmission electron microscopy; Vacancies; Magnesia; EELS; TEM

Astrophysics: tracking our neighbours' past - McConnachie, Alan (Nature, 2013)
The collective motions of dwarf galaxies in planes around the Andromeda galaxy and the Milky Way have presented a challenge to theory. Interactions between galaxy groups in the distant past may have left their imprint on these dwarfs.

Effect of using stencil masks made by focused ion beam milling on permalloy (Ni81Fe19) nanostructures - Bates, J. R.; Miyahara, Y.; Burgess, J. A. J.; Iglesias-Freire, Ó.; Grütter, P. (Nanotechnology, 2013)
Focused ion beam (FIB) milling is a common fabrication technique to make nanostencil masks which has the unintended consequence of gallium ion implantation surrounding milled features in silicon nitride membranes. We observe major changes in film structure, chemical composition, and magnetic behaviour of permalloy nanostructures deposited by electron beam evaporation using silicon nitride stencil masks made by a FIB as compared to stencil masks made by regular lithography techniques. We characterize the stenciled structures and both types of masks using transmission electron microscopy, electron energy loss spectroscopy, energy dispersive x-ray spectroscopy, magnetic force microscopy and kelvin probe force microscopy. All these techniques demonstrate distinct differences at a length scale of a 1-100 nm for the structures made using stencil mask fabricated using a FIB. The origin of these differences seems to be related to the presence of implanted ions, a detailed understanding of the mechanism however remains to be developed. © 2013 IOP Publishing Ltd.
Keywords: Chemical compositions; Electron beam evaporation; Energy dispersive X ray spectroscopy; Focused ion beam milling; Kelvin probe force microscopy; Permalloy nanostructures; Silicon nitride membrane; Unintended consequences; Electron beams; Electron energy loss spectroscopy; Ion implantation; Magnetic force microscopy; Nanostructures; Nickel alloys; Silicon nitride; Transmission electron microscopy; X ray spectroscopy; Focused ion beams

SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography - Mohammad, Mohammad Ali; Dew, Steven K.; Stepanova, Maria (Nanoscale Research Letters, 2013)
A detailed process characterization of SML electron beam resist for high-aspect-ratio nanopatterning at high sensitivity is presented. SML contrast curves were generated for methyl isobutyl ketone (MIBK), MIBK/isopropyl alcohol (IPA) (1:3), IPA/water (7:3), n-amyl acetate, xylene, and xylene/methanol (3:1) developers. Using IPA/water developer, the sensitivity of SML was improved considerably and found to be comparable to benchmark polymethylmethacrylate (PMMA) resist without affecting the aspect ratio performance. Employing 30-keV exposures and ultrasonic IPA/water development, an aspect ratio of 9:1 in 50-nm half-pitch dense grating patterns was achieved representing a greater than two times improvement over PMMA. Through demonstration of 25-nm lift-off features, the pattern transfer performance of SML is also addressed. © 2013 Mohammad et al.
Keywords: SML resist; Electron beam lithography; High-aspect-ratio nanolithography; Nanolithography; Nanofabrication; Lift-off; Preventing pattern collapse; Resists (85.40.Hp); Electron beam lithography (85.40.Hp); Nanolithography (81.16.Nd)

Doping and quantum confinement effects in single Si nanocrystals observed by scanning tunneling spectroscopy - Wolf, O.; Dasog, M.; Yang, Z.; Balberg, I.; Veinot, J. G. C.; Millo, O. (Nano Letters, 2013)
We have applied scanning tunneling spectroscopy in studies of the electronic level structure of surface-functionalized colloidal Si nanocrystals (Si-NCs) as a function of their size for various capping ligands. The energy gaps extracted from the tunneling spectra increase with decreasing NC size, manifesting the effect of quantum confinement. This is consistent with the blueshift revealed by photoluminescence (PL) from dodecene functionalized Si-NCs. The tunneling spectra measured on NCs functionalized with NH 4Br or allylamine show band-edge shifts toward higher energies, akin to p-type doping. This behavior can be accounted for by the combined contributions of the ligands' dipole moments and charge transfer between a Si-NC and its surface groups. Concomitantly, size-independent PL spectra, which cannot be associated with NC band gap variations, were observed for the latter Si-NCs. © 2013 American Chemical Society.
Keywords: Band gap variation; Capping ligands; Electronic levels; Quantum confinement effects; scanning-tunneling-spectroscopy; Silicon nanocrystals; surface-doping; Tunneling spectra; Charge transfer; Energy gap; Ligands; Nanocrystals; Photoluminescence; Quantum confinement; Scanning; Scanning tunneling microscopy; Spectroscopy; Silicon

Galaxy pairs in the local group - Fattahi, Azadeh; Navarro, Julio F.; Starkenburg, Else; Barber, Christopher R.; McConnachie, Alan W. (Monthly Notices of the Royal Astronomical Society: Letters, 2013)
Current models of galaxy formation predict that galaxy pairs of comparable magnitudes should become increasingly rare with decreasing luminosity. This seems at odds with the relatively high frequency of pairings among dwarf galaxies in the Local Group. We use literature data to show that ~30 per cent of all the satellites of the Milky Way and Andromeda galaxies brighter than Mv = -8 are found in likely physical pairs of comparable luminosity. Besides the previously recognized pairings of theMagellanic Clouds and of NGC 147/NGC 185, other candidate pairs include the Ursa Minor and Draco dwarf spheroidals, as well as the And I/And III satellites of M31. These pairs are much closer than expected by chance if the radial and angular distributions of satellites were uncorrelated; in addition, they have very similar line-of-sight velocities and luminosities that differ by less than three magnitudes. In contrast, the same criteria pair fewer than 4 per cent of satellites in N-body/semi-analytic models that match the radial distribution and luminosity function of Local Group satellites. If confirmed in studies of larger samples, the high frequency of dwarf galaxy pairings may provide interesting clues to the formation of faint galaxies in the current cosmological paradigm. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Young accreted globular clusters in the outer halo of m31 - Mackey, A. D.; Huxor, A. P.; Ferguson, A. M. N.; Irwin, M. J.; Veljanoski, J.; McConnachie, A. W.; Ibata, R. A.; Lewis, G. F.; Tanvir, N. R. (Monthly Notices of the Royal Astronomical Society, 2013)
We report on observations of two newly discovered globular clusters in the outskirts of M31 made using the Gemini Multi-Object Spectrograph (GMOS) instrument on Gemini North. These objects, PAndAS-7 (PA-7) and PAndAS-8 (PA-8), lie at a galactocentric radius of 87 kpc and are projected, with separation 19 kpc, on to a field halo substructure known as the South-West Cloud. We measure radial velocities for the two clusters which confirm that they are almost certainly physically associated with this feature. Colour-magnitude diagrams reveal strikingly short, exclusively red horizontal branches in both PA-7 and PA-8; both also have photometric [Fe/H]=-1.35±0.15. At this metallicity, the morphology of the horizontal branch is maximally sensitive to age, and we use the distinctive configurations seen in PA-7 and PA-8 to demonstrate that both objects are very likely to be at least 2 Gyr younger than the oldest Milky Way globular clusters. Our observations provide strong evidence for young globular clusters being accreted into the remote outer regions of M31 in a manner entirely consistent with the established picture for the Milky Way, and add credence to the idea that similar processes play a central role in determining the composition of globular cluster systems in large spiral galaxies in general. ©2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

The SUMO project I. A survey of multiple populations in globular clusters - Monelli, M.; Milone, A. P.; Stetson, P. B.; Marino, A. F.; Cassisi, S.; Molina, A. P.; Salaris, M.; Aparicio, A.; Asplund, M.; Grundahl, F.; Piotto, G.; Weiss, A.; et al. (Monthly Notices of the Royal Astronomical Society, 2013)
We present a general overview and the first results of the SUMO project (a SUrvey of Multiple pOpulations in Globular Clusters). The objective of this survey is the study of multiple stellar populations in the largest sample of globular clusters homogeneously analysed to date. To this aim we obtained high signal-to-noise (S/N > 50) photometry for main sequence stars with mass down to 0.5 M⊙ in a large sample of clusters using both archival and proprietary U, B, V and I data from ground-based telescopes. In this paper, we focus on the occurrence of multiple stellar populations in 23 clusters. We define a new photometric index, CU, B, I = (U - B) - (B - I), which turns out to be very effective for identifying multiple sequences along the red giant branch (RGB). We found that in the V-CU, B, I diagram all clusters presented in this paper show broadened or multimodal RGBs, with the presence of two or more components. We found a direct connection with the chemical properties of different sequences, which display different abundances of light elements (O, Na, C, N and Al). The CU, B, I index is also a powerful tool for identifying distinct sequences of stars along the horizontal branch and, for the first time in the case of NGC 104 (47 Tuc), along the asymptotic giant branch. Our results demonstrate that (i) the presence of more than two stellar populations is a common feature amongst globular clusters, as already highlighted in previous work; (ii) multiple sequences with different chemical contents can be easily identified by using standard Johnson photometry obtained with ground-based facilities; (iii) in the study of globular clustermultiple stellar populations the CU, B, I index is an alternative to spectroscopy, and has the advantage of larger statistics. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Dynamics in the satellite system of Triangulum: is And XXII a dwarf satellite of M33? - Chapman, S. C.; Widrow, L.; Collins, M. L. M.; Dubinski, J.; Ibata, R. A.; Rich, M.; Ferguson, A. M. N.; Irwin, M. J.; Lewis, G. F.; Martin, N.; McConnachie, A.; Peñarrubia, J.; et al. (Monthly Notices of the Royal Astronomical Society, 2013)
We present results from a spectroscopic survey of the dwarf spheroidal galaxy And XXII and the two extended clusters EC1 and EC2. These three objects are candidate satellites of the Triangulum galaxy, M33, which itself is likely a satellite of M31. We use the DEep Imaging Multi-Object Spectrograph (DEIMOS) mounted on the Keck II telescope to derive radial velocities for candidate member stars of these objects and thereby identify the stars that are most likely actual members. 11 probable stellar members are found for And XXII. We obtain an upper limit of σv < 6.0 km s-¹ for the velocity dispersion of And XXII, [Fe/H] ~ -1.6 for its metallicity and 255 pc for the Plummer radius of its projected density profile. We construct a colour-magnitude diagram for And XXII and identify both the red giant branch and the horizontal branch. The position of the latter is used to derive a heliocentric distance to And XXII of 853 ± 26 kpc. The combination of the radial velocity, distance and angular position of And XXII indicate that it is a strong candidate as the first known satellite of M33 and one of the very few examples of a galactic satellite of a satellite. N-body simulations imply that this conclusion is unchanged even if M31 and M33 had a strong encounter in the past few Gyr. We test the hypothesis that the extended clusters highlight tidally stripped galaxies by searching for an excess cloud of halo-like stars in their vicinity. We find such a cloud for the case of EC1 but not for EC2. The three objects imply a dynamical mass for M33 that is consistent with previous estimates. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Distant galaxy clusters in the XMM large scale structure survey - Willis, J. P.; Clerc, N.; Bremer, M. N.; Pierre, M.; Adami, C.; Ilbert, O.; Maughan, B.; Maurogordato, S.; Pacaud, F.; Valtchanov, I.; Chiappetti, L.; Thanjavur, K.; et al. (Monthly Notices of the Royal Astronomical Society, 2013)
Distant galaxy clusters provide important tests of the growth of large-scale structure in addition to highlighting the process of galaxy evolution in a consistently defined environment at large look-back time. We present a sample of 22 distant (z > 0.8) galaxy clusters and cluster candidates selected from the 9 deg² footprint of the overlapping X-ray Multi Mirror (XMM) Large Scale Structure (LSS), CFHTLS-Wide and Spitzer-SWIRE surveys. Clusters are selected as extended X-ray sources with an accompanying overdensity of galaxies displaying optical to mid-infrared photometry consistent with z > 0.8. Nine clusters have confirmed spectroscopic redshifts in the interval 0.8 < z < 1.2, four of which are presented here for the first time. A further 11 candidate clusters have between 8 and 10 band photometric redshifts in the interval 0.8 < z < 2.2, while the remaining two candidates do not have information in sufficient wavebands to generate a reliable photometric redshift. All of the candidate clusters reported in this paper are presented for the first time. Those confirmed and candidate clusters with available near-infrared photometry display evidence for a red sequence galaxy population, determined either individually or via a stacking analysis, whose colour is consistent with the expectation of an old, coeval stellar population observed at the cluster redshift. We further note that the sample displays a large range of red fraction values indicating that the clusters may be at different stages of red sequence assembly. We compare the observed X-ray emission to the flux expected from a suite of model clusters and find that the sample displays an effective mass limit M200 ∼ 1 × 10¹⁴ ⊙ with all clusters displaying masses consistent with M200 < 5 × 10¹⁴ M⊙. This XMM distant cluster study represents a complete sample of X-ray-selected z > 0.8 clusters. We discuss the importance of this sample to investigate the abundance of high-redshift clusters and to provide a relatively unbiased view of distant cluster galaxy populations. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

Speckle observations with PISCO in Merate (Italy) - XII. Astrometric measurements of visual binaries in 2011 - Scardia, M.; Prieur, J.-L.; Pansecchi, L.; Argyle, R. W.; Spanò, P.; Riva, M.; Landoni, M. (Monthly Notices of the Royal Astronomical Society, 2013)
We present relative astrometric measurements of visual binaries, made in 2011 with the Pupil Interferometry Speckle camera and COronagraph (PISCO) at the 102-cm Zeiss telescope of the Brera Astronomical Observatory in Merate (Italy). Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained new measurements of 469 objects, with angular separations in the range 0.14-8.1 arcsec, and an average accuracy of 0.02 arcsec. The mean error on the position angles is 0°.7. Most of the position angles were determined without the usual 180° ambiguity with the application of triple-correlation techniques and/or by inspection of the long integration files. Thanks to a newlow-magnification option included in PISCO, we have been able to observe fainter stars than previously. The limiting magnitude of our instrumentation on the Zeiss telescope is now close to mV = 10-12, which permits the observation of some red dwarfs. Finally, we present new revised orbits for ADS8739, 9182 Aa, Ab, 9626 Ba, Bb, 12880 and 14412, partly derived from those observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

V2494 cyg: A unique FU ori type object in the cygnus OB7 complex - Magakian, Tigran Yu.; Nikogossian, Elena H.; Movsessian, Tigran; Moiseev, Alexei; Aspin, Colin; Davis, Chris J.; Pyo, Tae-Soo; Khanzadyan, Tigran; Froebrich, Dirk; Smith, Michael D.; Moriarty-Schieven, Gerald H.; Beck, Tracy L. (Monthly Notices of the Royal Astronomical Society, 2013)
A photometric and spectral study of the variable star V2494 Cyg in the L 1003 dark cloud is presented. The brightness of the star, formerly known as HH 381 IRS, increased by 2.5 mag in R (probably in the 1980s) and since then has remained nearly constant. Since the brightness increase, V2494 Cyg has illuminated a bipolar cometary nebula. The stellar spectrum has several features typical of the FU Ori (FUor) type, plus it exhibits very strong Ha and forbidden emissionlines with high-velocity components. These emission lines originate in the Herbig-Haro (HH) jet near the star. The kinematic age of the jet is consistent with it forming at the time of the outburst leading to the luminosity increase. V2494 Cyg also produces a rather extended outflow; it is the first known FUor with both an observed outburst and a parsec-sized HH flow. The nebula, illuminated by V2494 Cyg, possesses similar morphological and spectral characteristics to Hubble's variable nebula (R Monocerotis/NGC 2261). © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

The VAST survey - III. The multiplicity of A-type stars within 75 pc - De Rosa, R. J.; Patience, J.; Wilson, P. A.; Schneider, A.; Wiktorowicz, S. J.; Vigan, A.; Marois, C.; Song, I.; Macintosh, B.; Graham, J. R.; Doyon, R.; Bessell, M. S.; et al. (Monthly Notices of the Royal Astronomical Society, 2013)

Newly discovered globular clusters in NGC 147 and NGC 185 from PAndAS - Veljanoski, J.; Ferguson, A. M. N.; Huxor, A. P.; Mackey, A. D.; Fishlock, C. K.; Irwin, M. J.; Tanvir, N.; Chapman, S. C.; Ibata, R. A.; Lewis, G. F.; McConnachie, A. (Monthly Notices of the Royal Astronomical Society, 2013)
Using data from the Pan-Andromeda Archaeological Survey (PAndAS), we have discovered four new globular clusters (GCs) associated with the M31 dwarf elliptical (dE) satellites NGC 147 and NGC 185. Three of these are associated with NGC 147 and one with NGC 185. All lie beyond the main optical boundaries of the galaxies and are the most remote clusters yet known in these systems. Radial velocities derived from low-resolution spectra are used to argue that the GCs are bound to the dwarfs and are not part of the M31 halo population. Combining PAndAS with United Kingdom Infrared Telescope (UKIRT)/WFCAM (Wide- Field Camera) data, we present the first homogeneous optical and near-IR photometry for the entireGCsystems of these dEs. Colour-colour plots and published colour-metallicity relations are employed to constrain GC ages and metallicities. It is demonstrated that the clusters are in general metal poor ([Fe/H] < -1.25 dex), while the ages are more difficult to constrain. The mean (V - η0 colours of the two GC systems are very similar to those of the GC systems of dEs in the Virgo and Fornax clusters, as well as the extended halo GC population in M31. The new clusters bring the GC-specific frequency (SN) to ~9 in NGC 147 and ~5 in NGC 185, consistent with values found for dEs of similar luminosity residing in a range of environments.
Keywords: galaxies: globular clusters: general; galaxies: individual: NGC 147; galaxies: individual: NGC 185

The James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey - IX. ¹²CO J = 3→2 observations of NGC 2976 and NGC 3351 - Tan, Boon-Kok; Leech, J.; Rigopoulou, D.; Warren, B. E.; Wilson, C. D.; Attewell, D.; Azimlu, M.; Bendo, G. J.; Butner, H. M.; Brinks, E.; Chanial, P.; Clements, D. L.; et al. (Monthly Notices of the Royal Astronomical Society, 2013)
We present ¹²CO J = 3→2 maps of NGC 2976 and NGC 3351 obtained with the James Clerk Maxwell Telescope (JCMT), both early targets of the JCMT Nearby Galaxy Legacy Survey (NGLS). We combine the present observations with ¹²CO J = 1→0 data and find that the computed ¹²CO J = 3→2 to ¹²CO J = 1→0 line ratio (R31) agrees with values measured in other NGLS field galaxies. We compute the MH2 value and find that it is robust against the value of R31 used. Using HI data from The HI Nearby Galaxy Survey, we find a tight correlation between the surface density of H2 and star formation rate density for NGC 3351 when ¹²CO J = 3→2 data are used. Finally, we compare the ¹²CO J = 3→2 intensity with the polycyclic aromatic hydrocarbon (PAH) 8 μm surface brightness and find a good correlation in the high surface brightness regions. We extend this study to include all 25 Spitzer Infrared Nearby Galaxies Survey galaxies within the NGLS sample and find a tight correlation at large spatial scales. We suggest that both PAH 8 μm and ¹²CO J = 3→2 are likely to originate in regions of active star formation. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

The orbital ellipticity of satellite galaxies and the mass of the Milky Way - Barber, Christopher; Starkenburg, Else; Navarro, Julio F.; McConnachie, Alan W.; Fattahi, Azadeh (Monthly Notices of the Royal Astronomical Society, 2013)
We use simulations of MilkyWay-sized dark matter haloes from the Aquarius Project to investigate the orbits of substructure haloes likely, according to a semi-analytic galaxy formation model, to host luminous satellites. These tend to populate the most massive subhaloes and are on more radial orbits than the majority of subhaloes found within the halo virial radius. One reason for this (mild) kinematic bias is that many low-mass subhaloes have apocentres that exceed the virial radius of the host; they are thus excluded from subhalo samples identified within the virial boundary, reducing the number of subhaloes on radial orbits. Two other factors contributing to the difference in orbital shape between dark and luminous subhaloes are their dynamical evolution after infall, which affects more markedly low-mass (dark) subhaloes, and a weak dependence of ellipticity on the redshift of first infall. The ellipticity distribution of luminous satellites exhibits little halo-to-halo scatter, and it may therefore be compared fruitfully with that of Milky Way satellites. Since the latter depends sensitively on the total mass of the Milky Way we can use the predicted distribution of satellite ellipticities to place constraints on this important parameter. Using the latest estimates of position and velocity of dwarfs compiled from the literature, we find that the most likely Milky Way mass lies in the range 6 × 1011M⊙ <M200 < 3.1 × 1012M⊙, with a best-fitting value of M200 = 1.1 × 1012M⊙. This value is consistent with Milky Way mass estimates based on dynamical tracers or the timing argument. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Portable bead-based fluorescence detection system for multiplex nucleic acid testing: a case study with Bacillus anthracis - Gravel, Jean-François; Geissler, Matthias; Chapdelaine, Sébastien; Boissinot, Karel; Voisin, Benoît; Charlebois, Isabelle; Poirier-Richard, Hugo-Pierre; Grégoire, Alexandre; Boissinot, Maurice; Bergeron, Michel G.; Veres, Teodor; Boudreau, Denis (Microfluidics and Nanofluidics, 2013)
This paper describes the design, functioning and use of a portable detection platform for multiplex nucleic acid testing. The system features a bead-supported DNA hybridization assay performed inside a microfluidic cartridge. Polystyrene particles modified with DNA capture probes are confined in the detection area and exposed to a solution of fluorescently labeled target DNA strands. The cartridge, fabricated from inexpensive thermoplastic polymers, allows for conducting up to eight assays in parallel. The detection instrument is equipped with a pneumatic module and a manifold lid serving as an interface to mediate fluid displacement on the cartridge. The fluorescence signal deriving from each assay is recorded by a semi-confocal fluorescence reader embedded in the detection platform. The compact design of the instrument and its level of integration make it possible to obtain an analytical result in less than 15 min, while only few manual steps need to be performed in between. A proof-of-concept demonstration involving Cy3-labeled, PCR-amplified genomic DNA confirms the ability to detect Bacillus anthracis in a multiplexed single-assay format using lef and capC genes. Limits of quantification are on the order of 1 × 109 copies/μL for lef targets. © 2013 Springer-Verlag Berlin Heidelberg.

The effect of a paraffin screen on the neutron dose at the maze door of a 15 MV linear accelerator - Krmar, M.; Nikolić, D.; Kuzmanović, A.; Kuzmanović, Z.; Ganezer, K. (Medical Physics, 2013)
Purpose: The purpose of this study was to explore the effects of a paraffin screen located at various positions in the maze on the neutron dose equivalent at the maze door. Methods: The neutron dose equivalent was measured at the maze door of a room containing a 15 MV linear accelerator for x-ray therapy. Measurements were performed for several positions of the paraffin screen covering only 27.5% of the cross-sectional area of the maze. The neutron dose equivalent was also measured at all screen positions. Two simple models of the neutron source were considered in which the first assumed that the source was the cross-sectional area at the inner entrance of the maze, radiating neutrons in an isotropic manner. In the second model the reduction in the neutron dose equivalent at the maze door due to the paraffin screen was considered to be a function of the mean values of the neutron fluence and energy at the screen. Results: The results of this study indicate that the equivalent dose at the maze door was reduced by a factor of 3 through the use of a paraffin screen that was placed inside the maze. It was also determined that the contributions to the dosage from areas that were not covered by the paraffin screen as viewed from the dosimeter, were 2.5 times higher than the contributions from the covered areas. This study also concluded that the contributions of the maze walls, ceiling, and floor to the total neutron dose equivalent were an order of magnitude lower than those from the surface at the far end of the maze. Conclusions: This study demonstrated that a paraffin screen could be used to reduce the neutron dose equivalent at the maze door by a factor of 3. This paper also found that the reduction of the neutron dose equivalent was a linear function of the area covered by the maze screen and that the decrease in the dose at the maze door could be modeled as an exponential function of the product ϕ¯·Ē at the screen.
Keywords: paraffin; dose response; dosimeter; linear accelerator; maze test; neutron dosimetry; radiotherapy

Improving biophysical properties of a bispecific antibody scaffold to aid developability: quality by molecular design - Von Kreudenstein, Thomas Spreter; Escobar-Carbrera, Eric; Lario, Paula I.; D'Angelo, Igor; Brault, Karine; Kelly, John F; Durocher, Yves; Baardsnes, Jason; Woods, R. Jeremy; Xie, Michael Hongwei; Girod, Pierre-Alain; Suits, Michael D. L.; et al. (mAbs, 2013)
While the concept of Quality-by-Design is addressed at the upstream and downstream process development stages, we questioned whether there are advantages to addressing the issues of biologics quality early in the design of the molecule based on fundamental biophysical characterization, and thereby reduce complexities in the product development stages. Although limited number of bispecific therapeutics are in clinic, these developments have been plagued with difficulty in producing materials of sufficient quality and quantity for both preclinical and clinical studies. The engineered heterodimeric Fc is an industry-wide favorite scaffold for the design of bispecific protein therapeutics because of its structural, and potentially pharmacokinetic, similarity to the natural antibody. Development of molecules based on this concept, however, is challenged by the presence of potential homodimer contamination and stability loss relative to the natural Fc. We engineered a heterodimeric Fc with high heterodimeric specificity that also retains natural Fclike biophysical properties, and demonstrate here that use of engineered Fc domains that mirror the natural system translates into an efficient and robust upstream stable cell line selection process as a first step toward a more developable therapeutic. © 2013 Landes Bioscience.
Keywords: bispecific antibody; homodimer; molecular scaffold; trastuzumab; binding affinity; computer model; controlled study; crystal structure; cytotoxicity; differential scanning calorimetry; drug purity; drug stability; Macaca fascicularis; mutation; preformulation; protein domain; protein engineering; qualitative analysis

Atomic layer deposition of TiN for the fabrication of nanomechanical resonators - Nelson-Fitzpatrick, Nathan; Guthy, Csaba; Poshtiban, Somayyeh; Finley, Eric; Harris, Kenneth D.; Worfolk, Brian J.; Evoy, Stephane (Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 2013)
Films of titanium nitride were grown by atomic layer deposition (ALD) over a range of temperatures from 120 °C to 300 °C, and their deposition rates were characterized by ellipsometry and reflectometry. The stress state of the films was evaluated by interferometry using a wafer bowing technique and varied from compressive (-18 MPa) to tensile (650 MPa). The crystal structure of the films was assessed by x-ray diffraction. The grain size varied with temperature in the range of 2-9 nm. The chemical composition of the films was ascertained by high-resolution x-ray photoelectron spectroscopy and showed the presence of O, Cl, and C contaminants. A mildly tensile (250 MPa) stressed film was employed for the fabrication (by electron beam lithography and reactive ion etching) of doubly clamped nanoresonator beams. The resonance frequency of resonators was assayed using an interferometric resonance testing apparatus. The devices exhibited sharp mechanical resonance peaks in the 17-25 MHz range. The uniformity and controllable deposition rate of ALD films make them ideal candidate materials for the fabrication of ultranarrow (<50 nm) nanobeam structures. © 2013 American Vacuum Society.
Keywords: Candidate materials; Chemical compositions; Grain size; High resolution; Mechanical resonance; Nano beams; Nanomechanical resonators; Reflectometry; Resonance frequencies; Resonance testing; Stress state; Deposition rates; Electron beam lithography; Fabrication; Films; Interferometry; Photoelectrons; Resonators; Titanium nitride; X ray diffraction; X ray photoelectron spectroscopy; Atomic layer deposition

Glancing angle deposition on a roll: towards high-throughput nanostructured thin films - Krause, Kathleen M.; Taschuk, Michael T.; Brett, Michael J. (Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 2013)
Increasing the throughput of the powerful single-step glancing angle deposition (GLAD) method using a prototype simplified roll-to-roll (R2R) system has been explored. While the conventional GLAD technique is popular for fabricating nanostructured devices in a single deposition step, it is not a high-output process. To evaluate the feasibility of large area GLAD deposition, the authors examined the geometrical considerations required to eventually achieve GLAD in a roll-to-roll manufacturing system. Nominal deposition and rotation angles were mathematically translated to their effective R2R counterparts, allowing for deposition recipes of the archetype GLAD nanostructures (slanted posts, vertical posts, and square spirals) and the mechanics of the phi-sweep technique to be converted to this space. Representative structures were then deposited, and the phi-sweep technique successfully applied, in a prototype single barrel roller R2R experimental system. This prototype system provides a foundation for moving GLAD from the laboratory to mass production. © 2013 American Vacuum Society.
Keywords: Geometrical considerations; Glancing angle deposition methods; Nanostructured thin film; Prototype system; Roll to roll manufacturing; Roll-to-roll system (R2R); Nanostructures; Deposition

Axial resistivity measurement of a nanopillar ensemble using a cross-bridge Kelvin architecture - Lalany, Abeed; Tucker, Ryan Thomac; Taschuk, Michael Thomas; Fleischauer, Michael David; Brett, Michael Julian (Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 2013)
Achieving the full potential of nanopillar electrode based devices, such as next-generation solar cells, catalyst supports, and sensors, requires axial resistivity measurements to optimize electronic performance. Here, the authors demonstrate a technique for direct measurement of the ensemble electrical properties of nanopillar thin films along the structures longitudinal axis. A cross-bridge Kelvin resistor architecture is adapted to accommodate an indium tin oxide (ITO) nanopillar thin film fabricated by glancing angle deposition (GLAD). As-deposited GLAD ITO nanopillars were found to have a measured resistivity of (1.1 ± 0.3) × 10-² Ω cm using our technique. Planar ITO films deposited at near normal incidence were found to have a resistivity of (4.5 ± 0.5) × 10-³ Ω cm, determined by the standard four-point-probe technique. These measurements demonstrate the viability of this modified technique for nanopillar characterization, and identify experimental limitations related to device size and edge defects. © 2013 American Vacuum Society.
Keywords: Cross-bridge kelvin resistors; Direct measurement; Electronic performance; Four-point probe techniques; Glancing Angle Deposition; Indium tin oxide; Longitudinal axis; Resistivity measurement; Deposits; Electric properties; Thin films; Tin oxides; Vapor deposition; Nanostructures

Plant biomass recalcitrance: effect of hemicellulose composition on nanoscale forces that control cell wall strength - Silveira, Rodrigo L.; Stoyanov, Stanislav R.; Gusarov, Sergey; Skaf, Munir S.; Kovalenko, Andriy (Journal of the American Chemical Society, 2013)
Efficient conversion of lignocellulosic biomass to second-generation biofuels and valuable chemicals requires decomposition of resilient plant cell wall structure. Cell wall recalcitrance varies among plant species and even phenotypes, depending on the chemical composition of the noncellulosic matrix. Changing the amount and composition of branches attached to the hemicellulose backbone can significantly alter the cell wall strength and microstructure. We address the effect of hemicellulose composition on primary cell wall assembly forces by using the 3D-RISM-KH molecular theory of solvation, which provides statistical-mechanical sampling and molecular picture of hemicellulose arrangement around cellulose. We show that hemicellulose branches of arabinose, glucuronic acid, and especially glucuronate strengthen the primary cell wall by strongly coordinating to hydrogen bond donor sites on the cellulose surface. We reveal molecular forces maintaining the cell wall structure and provide directions for genetic modulation of plants and pretreatment design to render biomass more amenable to processing. © 2013 American Chemical Society.
Keywords: Cell wall structure; Cellulose surfaces; Chemical compositions; Hydrogen bond donors; Lignocellulosic biomass; Molecular pictures; Molecular theory of solvation; Valuable chemicals; Cellulose; acetic acid; arabinose; carboxylic acid; functional group; glucuronic acid; hemicellulose; aqueous solution; chemical composition; decomposition; density; molecular recognition; molecular weight; phenotype; plant growth; proton transport; stereochemistry; thermodynamics

Family of phenylacetyl-CoA monooxygenases differs in subunit organization from other monooxygenases - Grishin, Andrey M.; Ajamian, Eunice; Tao, Limei; Bostina, Mihnea; Zhang, Linhua; Trempe, Jean-Francois; Menard, Robert; Rouiller, Isabelle; Cygler, Miroslaw (Journal of Structural Biology, 2013)
The phenylacetate degradation pathway is present in a wide range of microbes. A key component of this pathway is the four-subunit phenylacetyl-coenzyme A monooxygenase complex (PA-CoA MO, PaaACBE) that catalyzes the insertion of an oxygen in the aromatic ring of PA. This multicomponent enzyme represents a new family of monooxygenases. We have previously determined the structure of the PaaAC subcomplex of catalytic (A) and structural (C) subunits and shown that PaaACB form a stable complex. The PaaB subunit is unrelated to the small subunits of homologous monooxygenases and its role and organization of the PaaACB complex is unknown. From low-resolution crystal structure, electron microscopy and small angle X-ray scattering we show that the PaaACB complex forms heterohexamers, with a homodimer of PaaB bridging two PaaAC heterodimers. Modeling the interactions of reductase subunit PaaE with PaaACB suggested that a unique and conserved 'lysine bridge' constellation near the Fe-binding site in the PaaA subunit (Lys68, Glu49, Glu72 and Asp126) may form part of the electron transfer path from PaaE to the iron center. The crystal structure of the PaaA(K68Q/E49Q)-PaaC is very similar to the wild-type enzyme structure, but when combined with the PaaE subunit the mutant showed 20-50 times reduced activity, supporting the functional importance of the 'lysine bridge'. © 2013 Elsevier Inc.
Keywords: Monooxygenase; Phenylacetate degradation pathway; Aromatic compounds degradation; Quaternary structure

Structural and activity comparison of self-limiting versus traditional Pt electro-depositions on nanopillar Ni films - Francis, Sonja A.; Tucker, Ryan T.; Brett, Michael J.; Bergens, Steven H. (Journal of Power Sources, 2013)
We report the fabrication, characterisation, and electro-catalytic activity of <0.3 mg cm-² platinum deposits ontow500 nm long nickel nanopillar substrates (NiNP) synthesised by glancing angle deposition (GLAD). This is the first reported study of GLAD-based Pt-Ni electro-catalysts and the first alcohol oxidation study on any GLAD based electro-catalyst. The Pt was deposited onto NiNP via either 1) an unconventional, self-limiting, relatively high current density galvanostatic deposition, with a Pt counter electrode as the source of Pt, or 2) via a conventional potentiostatic deposition from Pt salts dissolved in acidic electrolytes. X-ray Diffraction (XRD) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) confirm the successful deposition of Pt onto NiNP, while Scanning Electron Microscopy (SEM) shows that the nanopillar morphology is preserved but the Pt morphology is significantly different between the two methods. The galvanostatic procedure resulted in a conformal Pt deposition over the entire surface of the NiNP. The conventional procedure appeared to be mass-transfer limited, with most of the Pt being deposited on the tops of the NiNP. Cyclic voltammetry in 1 M KOH shows an enhancement of the surface area of the catalysts upon Pt deposition and corroborates the presence of Pt on the NiNP surface. Both prepared catalysts show high electro-catalytic activity towards 2-propanol oxidation in the KOH electrolyte at 60 °C. The activity enhancement below 300 mV vs. RHE (RHE = reversible hydrogen electrode) was attributed to the combined activity of the Pt and Ni components in the catalysts. At higher potentials, a bifunctional mechanism was suggested. Finally, a geometric/composition effect may be at work in the traditionally deposited catalyst, and requires further investigation. © 2012 Elsevier B.V. All rights reserved.

Renormalization of effective mass in self-assembled quantum dots due to electron-electron interactions - Babinski, A.; Korkusinski, M.; Hawrylak, P.; Potemski, M.; Wasilewski, Z. R. (Journal of Physics: Conference Series, 2013)
Magnetic-field dispersion of the multiexcitons related to the p shell of a single quantum dot (QD) is analysed in this work. The reduced cyclotron effective mass of carriers is determined from the energy splitting between the p+-and p - related multiexcitonic emission lines. The reduced mass in the occupied QD was found to be larger than the mass related to the QD's single particle structure. The apparent increase of the reduced mass with increasing excitonic occupation of the dot is related to the mass renoralization due to electron-electron interactions within a multiexcitonic droplet. © Published under licence by IOP Publishing Ltd.
Keywords: Cyclotron-effective mass; Effective mass; Emission lines; Energy splittings; Renormalization; Self assembled quantum dots; Single particle; Single quantum dot; Electron-electron interactions; Magnetic fields; Semiconductor quantum dots

Red states versus blue states in colloidal silicon nanocrystals: exciton sequestration into low-density traps - Fuzell, Jack; Thibert, Arthur; Atkins, Tonya M.; Dasog, Mita; Busby, Erik; Veinot, Jonathan G. C.; Kauzlarich, Susan M.; Larsen, Delmar S. (The Journal of Physical Chemistry Letters, 2013)
The ultrafast exciton photodynamics of red-emitting and blue-emitting colloidal Si nanocrystals are contrasted under low (1.5 mJ/cm2) and high (9.1 mJ/cm2) excitation powers with broadband transient absorption spectroscopy. While the low-power initiated transient signals differ strongly for the two samples, the high-power signals exhibit similar nonmonotonic kinetics, resulting in a new population formed on a 10 to 30-ps time scale with a sample independent spectrum and decay kinetics. This phenomenon is ascribed to the saturation of low-density red-emitting and blue-emitting traps via a state-filling mechanism to populate new meta-stable states at higher excitation powers. The states responsible for blue emission and high-power populations are ascribed to traps from low-density nitrogen and oxygen impurities, respectively, and share similar charge-transfer character with the silicon nanocrystal core. © 2013 American Chemical Society.
Keywords: Excitation power; Exciton dynamics; Meta-stable state; Silicon nanocrystals; Silicon nanoparticles; State-filling; Transient absorption spectroscopies; Ultra-fast dynamics; Excited states; Optical waveguides; Excitons

Molecular docking of thiamine reveals similarity in binding properties between the prion protein and other thiamine-binding proteins - Pagadala, Nataraj S.; Bjorndahl, Trent C.; Blinov, Nikolay; Kovalenko, Andriy; Wishart, David S. (Journal of Molecular Modeling, 2013)
Prion-induced diseases are a global health concern. The lack of effective therapy and 100 % mortality rates for such diseases have made the prion protein an important target for drug discovery. Previous NMR experimental work revealed that thiamine and its derivatives bind the prion protein in a pocket near the N-terminal loop of helix 1, and conserved intermolecular interactions were noted between thiamine and other thiamine-binding proteins. Furthermore, water-mediated interactions were observed in all of the X-ray crystallographic structures of thiamine-binding proteins, but were not observed in the thiamine-prion NMR study. To better understand the potential role of water in thiamine-prion binding, a docking study was employed using structural X-ray solvent. Before energy minimization, docked thiamine assumed a "V" shape similar to some of the known thiamine-dependent proteins. Following minimization with NMR-derived restraints, the "F" conformation was observed. Our findings confirmed that water is involved in ligand stabilization and phosphate group interaction. The resulting refined structure of thiamine bound to the prion protein allowed the 4-aminopyrimidine ring of thiamine to π-stack with Tyr150, and facilitated hydrogen bonding between Asp147 and the amino group of 4-aminopyrimidine. Investigation of the π-stacking interaction through mutation of the tyrosine residue further revealed its importance in ligand placement. The resulting refined structure is in good agreement with previous experimental restraints, and is consistent with the pharmacophore model of thiamine-binding proteins. © 2013 Springer-Verlag Berlin Heidelberg.
Keywords: ligand; phosphate; prion protein; thiamine; tyrosine; water interaction; hydrogen bond; molecular docking; mutation; nuclear magnetic resonance; Pi stacking; protein binding; X ray crystallography

Silicon nanowire lithium-ion battery anodes with ALD deposited TiN coatings demonstrate a major improvement in cycling performance - Kohandehghan, Alireza; Kalisvaart, Peter; Cui, Kai; Kupsta, Martin; Memarzadeh, Elmira; Mitlin, David (Journal of Materials Chemistry A, 2013)
We demonstrate that nanometer-scale TiN coatings deposited by atomic layer deposition (ALD), and to a lesser extent by magnetron sputtering, will significantly improve the electrochemical cycling performance of silicon nanowire lithium-ion battery (LIB) anodes. A 5 nm thick ALD coating resulted in optimum cycling capacity retention (55% vs. 30% for the bare nanowire baseline, after 100 cycles) and coulombic efficiency (98% vs. 95%, at 50 cycles), also more than doubling the high rate capacity retention (e.g. 740 mA h g-¹ vs. 330 mA h g-¹, at 5 C). We employed a variety of advanced analytical techniques such as electron energy loss spectroscopy (EELS), focused ion beam analysis (FIB) and X-ray photoelectron spectroscopy (XPS) to elucidate the origin of these effects. The conformal 5 nm TiN remains sufficiently intact to limit the growth of the solid electrolyte interphase (SEI), which in turn both improves the overall coulombic efficiency and reduces the life-ending delamination of the nanowire assemblies from the underlying current collector. Our findings should provide a broadly applicable coating design methodology that will improve the performance of any nanostructured LIB anodes where SEI growth is detrimental. © 2013 The Royal Society of Chemistry.
Keywords: Coulombic efficiency; Electrochemical cycling; Focused ion beam analysis; High-rate capacities; Lithium-ion battery; Lithium-ion battery anodes; Nanowire assemblies; Solid electrolyte interphase; Anodes; Coatings; Electron energy loss spectroscopy; Lithium batteries; Nanowires; Photoelectrons; Silicon; Solid electrolytes; Titanium nitride; X ray photoelectron spectroscopy; Atomic layer deposition

Linking the chemistry and physics of electronic charge transfer in insulators: theory and experiment - Veregin, Richard P. N.; Hawkins, Michael S.; Li, Qingbin; Gusarov, Sergey; Kovalenko, Andriy (Journal of Imaging Science and Technology, 2013)
The surface states model is successful in predicting many salient features of charge transfer in insulative materials, which is critical to electrophotography. This article will discuss how the surface chemistry controls the physics and the chemical potentials, and how it fits the surface states model. The interrelationship of acid-base Ka/Kb values of the materials in contact, measured by inverse gas chromatography, the highest occupied molecular orbitals and lowest unoccupied molecular orbitals and their excited states calculated using DFT (density functional theory) quantum mechanical modeling, the chemical potentials measured by the Kelvin method, and triboelectric charging data are studied. It will be shown that a precursor complex of the contacting materials, prior to the charge transfer event, can be calculated by DFT to predict triboelectric charging both qualitatively and quantitatively. This article focuses on polytetrafluoroethylene, Kynar and PMMA polymers, as well as silica, titania, and alumina. © 2013 Society for Imaging Science and Technology.
Keywords: Electronic charges; Electrophotography; Highest occupied molecular orbital; Inverse gas chromatography; Lowest unoccupied molecular orbital; Precursor complexes; Quantum mechanical model; Triboelectric charging; Alumina; Chemical potential; Gas chromatography; Molecular orbitals; Photography; Quantum theory; Surface chemistry; Surface states; Charge transfer

Ultrathin-layer chromatography nanostructures modified by atomic layer deposition - Jim, S. R.; Foroughi-Abari, A.; Krause, K. M.; Li, P.; Kupsta, M.; Taschuk, M. T.; Cadien, K. C.; Brett, M. J. (Journal of Chromatography A, 2013)
Stationary phase morphology and surface chemistry dictate the properties of ultrathin-layer chromatography (UTLC) media and interactions with analytes in sample mixtures. In this paper, we combined two powerful thin film deposition techniques to create composite chromatography nanomaterials. Glancing angle deposition (GLAD) produces high surface area columnar microstructures with aligned macropores well-suited for UTLC. Atomic layer deposition (ALD) enables precise fabrication of conformal, nanometer-scale coatings that can tune surfaces of these UTLC films. We coated ~5μm thick GLAD SiO2 UTLC media with <10nm thick ALD metal oxides (Al2O3, ZrO2, and ZnO) to decouple surface chemistry from the underlying GLAD scaffold microstructure. The effects of ALD coatings on GLAD UTLC media were investigated using transmission electron microscopy (TEM), gas adsorption porosimetry, and lipophilic dye separations. The results collectively show that the most significant changes occur over the first few nanometers of ALD coating. They further demonstrate independent control of film microstructure and surface characteristics. ALD coatings can enhance complex GLAD microstructures to engineer new composite nanomaterials potentially useful in analytical chromatography. © 2013 Elsevier B.V..
Keywords: Thin layer chromatography (TLC); Ultrathin-layer chromatography (UTLC); Glancing angle deposition (GLAD); Atomic layer deposition (ALD); Nanostructured thin films; Surface functionalization

Ultrathin-layer chromatography on SiO2, Al2O3, TiO2, and ZrO2 nanostructured thin films - Wannenmacher, Julia; Jim, Steven R.; Taschuk, Michael T.; Brett, Michael J.; Morlock, Gertrud E. (Journal of Chromatography A, 2013)
We explored four different inorganic oxides and determined their merits in miniaturized planar chromatography. Despite progression of chromatographic techniques over several decades, such alternatives to traditional planar silica gel stationary phases have not been fully evaluated. Glancing angle deposition (GLAD) provided an excellent platform for engineering nanostructured thin films in these materials for ultrathin-layer chromatography (UTLC). Separations of carotenoids and synthetic food dyes were used to investigate the attributes of SiO2, Al2O3, TiO2, and ZrO2 GLAD UTLC media. These anisotropic high surface area thin films possessed similar channel-like features but different chromatographic properties. TiO2 and ZrO2 media were especially interesting since analyte retention could be modified through simple oxidation heat treatments and UV irradiation. Generally, oxidation reduced analyte retention while UV exposure increased retention. Changes in retention factor as large as δhRF~40 (for Acid Red 14 on titanium oxide) were achieved. Food dye mixtures were applied using consumer inkjet printers as per the Office Chromatography concept and separation performance was quantified using advanced video instrumentation designed for miniaturized plates. Enhanced time-resolved UTLC methods were used to calculate figures of merit from recorded dye separation videos. Small theoretical plate heights (<4μm) and low limits of detection (<2ng per zone for the food dye tartrazine) were measured. The combination of engineered GLAD UTLC plates, inkjet application of analyte spots, time-resolved UTLC, and custom analysis algorithms enabled some of the best performance achieved on GLAD UTLC layers. Separations on the inorganic oxide thin films were also successfully hyphenated with electrospray ionization mass spectrometry for the first time. This investigation demonstrates the utility of alternative inorganic oxide GLAD UTLC media and probes avenues of expanding the capabilities of miniaturized planar chromatography. © 2013 Elsevier B.V.
Keywords: Miniaturized planar chromatography; Glancing angle deposition (GLAD); Office Chromatography; Mass spectrometry; Oxidation; Ultraviolet irradiation

Grand-canonical quantized liquid density-functional theory in a Car-Parrinello implementation - Walther, Christian F. J.; Patchkovskii, Serguei; Heine, Thomas (The Journal of Chemical Physics, 2013)
Quantized Liquid Density-Functional Theory (QLDFT) [S. Patchkovskii and T. Heine, Phys. Rev. E 80, 031603 (2009)], a method developed to assess the adsorption of gas molecules in porous nanomaterials, is reformulated within the grand canonical ensemble. With the grand potential it is possible to compare directly external and internal thermodynamic quantities. In our new implementation, the grand potential is minimized utilizing the Car-Parrinello approach and gives, in particular for low temperature simulations, a significant computational advantage over the original canonical approaches. The method is validated against original QLDFT, and applied to model potentials and graphite slit pores. © 2013 AIP Publishing LLC.
Keywords: Car-Parrinello approaches; Computational advantages; Gas molecules; Grand canonical ensemble; Grand potential; Low temperatures; Model potential; Thermodynamic quantities; Density functional theory; Density of liquids

Multiple time step molecular dynamics in the optimized isokinetic ensemble steered with the molecular theory of solvation: Accelerating with advanced extrapolation of effective solvation forces - Omelyan, Igor; Kovalenko, Andriy (The Journal of Chemical Physics, 2013)
We develop efficient handling of solvation forces in the multiscale method of multiple time step molecular dynamics (MTS-MD) of a biomolecule steered by the solvation free energy (effective solvation forces) obtained from the 3D-RISM-KH molecular theory of solvation (three-dimensional reference interaction site model complemented with the Kovalenko-Hirata closure approximation). To reduce the computational expenses, we calculate the effective solvation forces acting on the biomolecule by using advanced solvation force extrapolation (ASFE) at inner time steps while converging the 3D-RISM-KH integral equations only at large outer time steps. The idea of ASFE consists in developing a discrete non-Eckart rotational transformation of atomic coordinates that minimizes the distances between the atomic positions of the biomolecule at different time moments. The effective solvation forces for the biomolecule in a current conformation at an inner time step are then extrapolated in the transformed subspace of those at outer time steps by using a modified least square fit approach applied to a relatively small number of the best force-coordinate pairs. The latter are selected from an extended set collecting the effective solvation forces obtained from 3D-RISM-KH at outer time steps over a broad time interval. The MTS-MD integration with effective solvation forces obtained by converging 3D-RISM-KH at outer time steps and applying ASFE at inner time steps is stabilized by employing the optimized isokinetic Nosé-Hoover chain (OIN) ensemble. Compared to the previous extrapolation schemes used in combination with the Langevin thermostat, the ASFE approach substantially improves the accuracy of evaluation of effective solvation forces and in combination with the OIN thermostat enables a dramatic increase of outer time steps. We demonstrate on a fully flexible model of alanine dipeptide in aqueous solution that the MTS-MD/OIN/ASFE/3D-RISM-KH multiscale method of molecular dynamics steered by effective solvation forces allows huge outer time steps up to tens of picoseconds without affecting the equilibrium and conformational properties, and thus provides a 100- to 500-fold effective speedup in comparison to conventional MD with explicit solvent. With the statistical-mechanical 3D-RISM-KH account for effective solvation forces, the method provides efficient sampling of biomolecular processes with slow and/or rare solvation events such as conformational transitions of hydrated alanine dipeptide with the mean life times ranging from 30 ps up to 10 ns for "flip-flop" conformations, and is particularly beneficial for biomolecular systems with exchange and localization of solvent and ions, ligand binding, and molecular recognition. © 2013 AIP Publishing LLC.
Keywords: Conformational properties; Conformational transitions; Extrapolation schemes; Modified least squares; Molecular theory of solvation; Reference interaction site models; Rotational transformation; Solvation free energies; Amino acids; Approximation theory; Biomolecules; Conformations; Extrapolation; Molecular dynamics; Optimization; Sampling; Structural analysis; Thermostats; Three dimensional

Self-assembled rosette nanotubes and poly(2-hydroxyethyl methacrylate) hydrogels promote skin cell functions - Sun, Linlin; Li, Dongni; Hemraz, Usha D.; Fenniri, Hicham; Webster, Thomas J. (Journal of Biomedical Materials Research - Part A, 2013)
The next generation skin of wound healing materials should stimulate skin regeneration by actively promoting appropriate cellular adhesion and proliferation. As materials with novel self-assembling and solidification properties when transitioning from room to body temperatures, rosette nanotubes (RNTs) may be such a proactive material. RNTs resemble naturally occurring nanostructures in the skin (such as collagen and keratin) assembling with noncovalent forces in physiological environments. Presenting desirable bioactive properties, RNTs have been used for various tissue engineering applications including increasing in vivo bone and cartilage regeneration. The objective of the current in vitro study was, for the first time, to improve properties of a commonly used hydrogel (poly(2-hydroxyethyl methacrylate) or pHEMA) for skin regeneration by incorporating one type of novel self-assembled RNTs, called TBL. Results showed for the first time increased keratinocyte and fibroblast proliferation on hydrogels coated with TBLs compared to those not coated with TBL. In this manner, this study provides the first evidence that TBL RNTs are promising for wound healing applications due to their optimal cytocompatibility, solidification, and mechanical properties and, thus, should be further studied for such applications. © 2013 Wiley Periodicals, Inc.

Comparisons between multiple in-situ aircraft turbulence measurements and radar in the troposphere - Dehghan, Armin; Hocking, Wayne K.; Srinivasan, Ramesh (Journal of Atmospheric and Solar-Terrestrial Physics, 2013)
Networks of Windprofiler Radars have the capability to make significant contributions to severe weather forecasting (both on the ground and in the air) through the determination of real-time turbulence strengths, but the potential has still not been fully realized. In order to better understand the accuracy of profilers in determination of turbulence strengths, we have compared radar measurements made at the Harrow radar in Canada (located in Southwestern Ontario as part of the O-QNet radar network) with in-situ measurements made by multiple aircraft. These included measurements made both by commercial aircraft and dedicated research aircraft. Research aircraft (instrumented with accelerometers and GPS tracking devices) and radar data were analysed using structure function, spectral and spectral-width methods. Data were also recorded on-board commercial aircraft using accelerometer-based studies, and results were recorded for subsequent analyses. Over 92,000 commercial aircraft measurements, 4000 h of radar data, and 15 days of research-aircraft measurements were available for this study, although only a subset of the commercial aircraft data were useable. The radar-based spectral-width method occasionally produced anomalous negative values of the turbulence strength, usually associated with weak turbulence coupled with significant wind variability over scales of tens of kms, but the aircraft data also had limitations. For the commercial aircraft, frequent zeros were common, also associated with weak turbulence. With regard to the research aircraft measurements, it was found through both spectral and structure function analyses that spectral contaminants exist out to scales of many tens of metres (larger than often assumed), but proper allowance for these effects permitted good estimates of turbulence strength. Spatial and temporal variability was large, however, complicating comparisons with the radar. By comparing the in-situ data to the radar data, it has been possible to place stronger limits on the constants used to determine radar turbulence strengths. Subsequent comparisons with the commercial aircraft data over a six-month period have then been used to show that aircraft and radar probability distributions agree in form, but that the aircraft data are three to five times larger. Corrections for this bias lead to good agreement, both in form and absolute values, for all three data sets. Crown Copyright © 2013.

Towards engineered branch placement: Unreal™ match between vapour-liquid-solid glancing angle deposition nanowire growth and simulation - Taschuk, M. T.; Tucker, R. T.; LaForge, J. M.; Beaudry, A. L.; Kupsta, M. R.; Brett, M. J. (Journal of Applied Physics, 2013)
The vapour-liquid-solid glancing angle deposition (VLS-GLAD) process is capable of producing complex nanotree structures with control over azimuthal branch orientation and height. We have developed a thin film growth simulation including ballistic deposition, simplified surface diffusion, and droplet-mediated cubic crystal growth for the VLS-GLAD process using the UnrealTM Development Kit. The use of a commercial game engine has provided an interactive environment while allowing a custom physics implementation. Our simulation's output is verified against experimental data, including a volumetric film reconstruction produced using focused ion beam and scanning-electron microscopy (SEM), crystallographic texture, and morphological characteristics such as branch orientation. We achieve excellent morphological and texture agreement with experimental data, as well as qualitative agreement with SEM imagery. The simplified physics in our model reproduces the experimental films, indicating that the dominant role flux geometry plays in the VLS-GLAD competitive growth process responsible for azimuthally oriented branches and biaxial crystal texture evolution. The simulation's successful reproduction of experimental data indicates that it should have predictive power in designing novel VLS-GLAD structures. © 2013 Crown.
Keywords: Ballistic deposition; Competitive growth; Crystallographic textures; Glancing Angle Deposition; Interactive Environments; Morphological characteristic; Nanowire growth; Predictive power; Film growth; Liquids; Motion pictures; Nanowires; Scanning electron microscopy; Textures; Vapors; Deposition

Fractional Fourier analysis of random signals and the notion of α -Stationarity of the Wigner-Ville distribution - Torres, Rafael; Torres, Edmanuel (IEEE Transactions on Signal Processing, 2013)
In this paper, a generalized notion of wide-sense α-stationarity for random signals is presented. The notion of stationarity is fundamental in the Fourier analysis of random signals. For this purpose, a definition of the fractional correlation between two random variables is introduced. It is shown that for wide-sense α-stationary random signals, the fractional correlation and the fractional power spectral density functions form a fractional Fourier transform pair. Thus, the concept of α-stationarity plays an important role in the analysis of random signals through the fractional Fourier transform for signals nonstationary in the standard formulation, but α-stationary. Furthermore, we define the α-Wigner-Ville distribution in terms of the fractional correlation function, in which the standard Fourier analysis is the particular case for α=pi2, and it leads to the Wiener-Khinchin theorem. © 1991-2012 IEEE.
Keywords: Fractional correlation; Fractional Fourier Transformations; Fractional power spectral density; Random signal; Wiener-Khinchin theorem; Fourier optics; Power spectral density; Wigner-Ville distribution; Fourier analysis

Mineralogical controls on aluminum and magnesium in uranium mill tailings: Key Lake, Saskatchewan, Canada - Gomez, M. A.; Hendry, M. J.; Koshinsky, J.; Essilfie-Dughan, J.; Paikaray, S.; Chen, J. (Environmental Science and Technology, 2013)
The mineralogy and evolution of Al and Mg in U mill tailings are poorly understood. Elemental analyses (ICP-MS) of both solid and aqueous phases show that precipitation of large masses of secondary Al and Mg mineral phases occurs throughout the raffinate neutralization process (pH 1-11) at the Key Lake U mill, Saskatchewan, Canada. Data from a suite of analytical methods (ICP-MS, EMPA, laboratory- and synchrotron-based XRD, ATR-IR, Raman, TEM, EDX, ED) and equilibrium thermodynamic modeling showed that nanoparticle-sized, spongy, porous, Mg-Al hydrotalcite is the dominant mineralogical control on Al and Mg in the neutralized raffinate (pH ≥ 6.7). The presence of this secondary Mg-Al hydrotalcite in mineral samples of both fresh and 15-year-old tailings indicates that the Mg-Al hydrotalcite is geochemically stable, even after >16 years in the oxic tailings body. Data shows an association between the Mg-Al hydrotalcite and both As and Ni and point to this Mg-Al hydrotalcite exerting a mineralogical control on the solubility of these contaminants. © 2013 American Chemical Society.

Five helicopter accidents with evidence of material and/or design deficiencies - Wanhill, R. J. H.; Symonds, N.; Merati, A.; Pasang, T.; Lynch, S. P. (Engineering Failure Analysis, 2013)
Most helicopter accidents are due to problems concerning flight operations, ground duties (mission planning and preparation), training and instructions. These are key issues within the current (European) strategies for greatly reducing the number of accidents in the next few years. However, when accidents occur the subsequent investigations should include or at least consider forensic engineering, even if only to eliminate possible causes like material defects, component and systems failures, and design deficiencies. To illustrate this, the present paper discusses five helicopter accidents with evidence of material and/or design deficiencies. The accidents concerned a Sikorsky S-61N (1974), an Aérospatiale Alouette III (1990), a Westland Lynx SH14D (1998), and two AgustaWestland EH101s (2004, 2006). © 2012 Elsevier Ltd.
Keywords: Agusta westland; Design deficiencies; Flight operation; Material defect; Mission planning; Sikorsky; Systems failure; Failure analysis; Forensic engineering; Fractography; Fracture mechanics; Helicopter services; Helicopters; Accidents

Mesoporous nitrogen-rich carbons derived from protein for ultra-high capacity battery anodes and supercapacitors - Li, Zhi; Xu, Zhanwei; Tan, Xuehai; Wang, Huanlei; Holt, Chris M. B.; Stephenson, Tyler; Olsen, Brian C.; Mitlin, David (Energy and Environmental Science, 2013)
In this work we demonstrate that biomass-derived proteins serve as an ideal precursor for synthesizing carbon materials for energy applications. The unique composition and structure of the carbons resulted in very promising electrochemical energy storage performance. We obtained a reversible lithium storage capacity of 1780 mA h g-1, which is among the highest ever reported for any carbon-based electrode. Tested as a supercapacitor, the carbons exhibited a capacitance of 390 F g-1, with an excellent cycle life (7% loss after 10000 cycles). Such exquisite properties may be attributed to a unique combination of a high specific surface area, partial graphitization and very high bulk nitrogen content. It is a major challenge to derive carbons possessing all three attributes. By templating the structure of mesoporous cellular foam with egg white-derived proteins, we were able to obtain hierarchically mesoporous (pores centered at ∼4 nm and at 20-30 nm) partially graphitized carbons with a surface area of 805.7 m2 g -1 and a bulk N-content of 10.1 wt%. When the best performing sample was heated in Ar to eliminate most of the nitrogen, the Li storage capacity and the specific capacitance dropped to 716 mA h g-1 and 80 F g -1, respectively. © 2013 The Royal Society of Chemistry.
Keywords: Carbon-based electrodes; Electrochemical energy storage; Energy applications; Graphitized carbons; High specific surface area; Lithium storage capacity; Nitrogen content; Specific capacitance; Capacitors; Graphitization; Mesoporous materials; Proteins; Biosynthesis; Electrochemistry; Foam

Disruption of biomolecule function by nanoparticles: how do gold nanoparticles affect Phase I biotransformation of persistent organic pollutants? - Lu, Zhe; Ma, Guibin; Veinot, Johnathan G. C.; Wong, Charles S. (Chemosphere, 2013)
The potential influence of nanoparticles on cytochrome P-450 (CYP) isozyme mediated Phase I biotransformation of persistent organic pollutants (POPs) in vitro was investigated using citrate-capped gold nanoparticles (AuNPs) and 2,2',3,5',6-pentachlorobiphenyl (PCB 95) as the probe nanoparticle and compound, respectively. AuNPs affected the biotransformation activity of rat CYP2B1 and changed the atropisomeric composition of PCB 95, depending on the incubation time and the AuNP concentration. Electrostatic repulsion between citrate-coated AuNPs and rat CYP2B1 may influence the active conformation of the isozyme and consequently affect its activity and stereoselectivity. In addition, the effects of AuNPs on rat CYP2B1 activity also appeared to be through interference with the CYP catalytic cycle's electron transfer chain. Incubations with AuNPs had a decline in buffer conductance and an absorbance band red shift of AuNPs, from electrostatic interactions of K+ with negatively-charged AuNP aggregates. These ionic strength changes affected the formation rate of nicotinamide adenine dinucleotide phosphate, which provides electrons for the oxidative reaction cycle, and the biotransformation activity and stereoselectivity of CYP. This study suggests that charged nanoparticles may be able to alter the functions of biomolecules directly, by electrostatic interaction, or indirectly, by changes to the surrounding ionic strength. These factors should be taken into account for further understanding and prediction of the environmental behavior and fate of POPs and nanoparticles. © 2013 Elsevier Ltd.
Keywords: Nanoparticles; Cytochrome P-450; Chiral organic pollutants; Ionic strength; Disruption

Nanocrystalline anatase TiO2: a new anode material for rechargeable sodium ion batteries - Xu, Yang; Memarzadeh Lotfabad, Elmira; Wang, Huanlei; Farbod, Behdokht; Xu, Zhanwei; Kohandehghan, Alireza; Mitlin, David (Chemical Communications, 2013)
Anatase TiO2 nanocrystals were successfully employed as anodes for rechargeable Na-ion batteries for the first time. The mesoporous electrodes exhibited a highly stable reversible charge storage capacity of ∼150 mA h g-¹ over 100 cycles, and were able to withstand high rate cycling, fully recovering this capacity after being cycled at rates as high as 2 A g-¹.
Keywords: anatase nanocrystal; carbon; nanocrystal; sodium ion; titanium dioxide; unclassified drug; adsorption; desorption; electric battery; electrode; sodium ion battery; storage

Comparison of the morphology of alkali-silica gel formed in limestones in concrete affected by the so-called alkali-carbonate reaction (ACR) and alkali-silica reaction (ASR) - Grattan-Bellew, P. E.; Chan, Gordon (Cement and Concrete Research, 2013)
The morphology of alkali-silica gel formed in dolomitic limestone affected by the so-called alkali-carbonate reaction (ACR) is compared to that formed in a siliceous limestone affected by alkali-silica reaction (ASR). The particle of dolomitic limestone was extracted from the experimental sidewalk in Kingston, Ontario, Canada that was badly cracked due to ACR. The siliceous limestone particle was extracted from a core taken from a highway structure in Quebec, affected by ASR. Both cores exhibited marked reaction rims around limestone particles. The aggregate particles were polished and given a light gold coating in preparation for examination in a scanning electron microscope. The gel in the ACR aggregate formed stringers between the calcite crystals in the matrix of the rock, whereas gel in ASR concrete formed a thick layer on top of the calcite crystals, that are of the same size as in the ACR aggregate. © 2013 Elsevier Ltd.
Keywords: Aggregate particles; Alkali carbonate reaction; Alkali-silica reaction; Dolomitic limestone; Highway structures; Limestone particles; Scanning Electron Microscope; SEM-EDX; Calcite; Carbonation; Concretes; Morphology; Scanning electron microscopy; Silica gel; Stringers; Aggregates

Microbubble-enhanced cell membrane permeability in high gravity field - He, Chuan; Gu, Quanrong; Zeng, Hongbo; Zhang, Hao; Huang, Min; Yang, Xiaoyan; Xing, James; Chen, Jie (Cellular and Molecular Bioengineering, 2013)
Cell permeability controls the transportation of extracellular materials through cell membranes, which plays a critical role in drug and gene delivery. This work reports an innovative method to enhance the cell permeability through cell-bubble interactions in a high gravity field. In the presence of microbubbles, the cell membrane permeability of mammalian cells was significantly increased in the high gravity field, and up to 80% THP-1 and 70% MCF-7 cells were permeabilized by using FITC-Dextran with average molecular weight of 40 and 70 kDa as fluorescent markers which were found to locate in both cytoplasm and cell nucleus by using a confocal microscope. Micro-scale pores were detected on the cell membrane by a scanning electron microscope after the cellmicrobubble interactions in the high gravity field. The delivery efficiency of FITC-Dextran could be further enhanced in gravity field of higher strength and in solutions with higher volume fraction of microbubbles, though the cell viability would also fall under extreme conditions. A simplified model was proposed to compare the contributions of surface forces (i.e., Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction force and membrane undulation force) with hydrodynamic force associated with cell-bubble interactions in the high gravity field. The hydrodynamic force was found to dominate the cell-bubble interaction while the DLVO force and membrane undulation force only play an important role at small separation (≤10 nm) and low relative velocity of approach (i.e., low gravity field strength). The enhanced cell membrane permeability and formation of micro-scale pores are mainly due to the microbubble-cell interactions through collision and/ or cavitation effects from the bursting of microbubbles. Our results have important implications in many bioengineering processes which are dependent on cell membrane permeability. © 2013 Biomedical Engineering Society.
Keywords: Cell membrane permeability; Microbubbles; DLVO force; Hydrodynamic force; High gravity field; Cavitation; THP-1 monocytes; MCF-7 cells

Koopmans' multiconfigurational self-consistent field (MCSCF) Fukui functions and MCSCF perturbation theory - Gusarov, Serguey; Dmitriev, Yuri Yu; Stoyanov, Stanislav R.; Kovalenko, Andriy (Canadian Journal of Chemistry, 2013)
Prediction of chemical reactivity has become one of the highest priority tasks of computational chemistry since the development of the methods of modeling electronic structure. Despite the general simplicity of the physical concept of reactivity and the rapid development of modern density functional theory (DFT) methods, this task remains state-of-the-art for systems with wavefunctions that have a multiconfigurational character. In such cases, for the accurate description of reactivity one needs to use multiconfigurational approaches that are much heavier computationally then ordinary single-determinant DFT methods. Moreover, the complexity of the calculation of reactivity is increased by the necessity to calculate ionic and transition states. These computational challenges can be addressed by employing the concepts of Koopmans' theorem and its extension to a multiconfigurational case. We present a simplified methodology for the calculation of Fukui functions, based on Koopmans' approximation for multiconfigurational Green's functions developed in our previous works. Also, an extension of this methodology based on perturbation theory has been developed to improve accuracy. © 2013 Published by NRC Research Press.
Keywords: Computational challenges; Density functional theory methods; Extended Koopmans' approximation; Fukui functions; Multiconfigurational self-consistent fields; Perturbation theory; Priority tasks; Transition state; Chemical reactivity; Electronic structure; Green's function

Density functional theory investigation of the effect of axial coordination and annelation on the absorption spectroscopy of nickel(II) and vanadyl porphyrins relevant to bitumen and crude oils - Stoyanov, Stanislav R.; Yin, Cindy-Xing; Gray, Murray R.; Stryker, Jeffrey M.; Gusarov, Serguey; Kovalenko, Andriy (Canadian Journal of Chemistry, 2013)
The vanadium and nickel components in heavy oils and bitumen are important impurities in catalytic processing and form aggregates with other asphaltene components. Metalloporphyrins are commonly analyzed using the characteristic Soret band in the UV-vis absorption spectrum. However, the Soret band of metalloporphyrins in petroleum is broadened and weaker than expected based on the concentration of Ni and V in heavy oils and the extinction coefficients of isolated porphyrins. We hypothesize that the low intensity and broadening of the Soret band could be due to axial coordination of the metal center or fusion (annelation) of aromatic rings on the porphyrin π-system. This hypothesis is examined using the density functional theory for geometry optimization and time-dependent density functional theory (TD-DFT) for calculation of excited states of nickel(II) and vanadyl porphyrins with axially coordinated ligands and annelated polyaromatic hydrocarbons. Predictions of the excited electronic states performed using the tandem of TD-DFT and conductor-like polarizable continuum model of solvation support this hypothesis and provide insight into the extent of Soret band broadening and intensity decrease due to coordination and annelation. These computational results, validated with respect to visible absorption spectra, are important for understanding asphaltene aggregation and spectroscopic characterization and suggest methods for removal of transition metals from heavy oil. © 2013 Published by NRC Research Press.
Keywords: Annelation; Axial coordination; Bitumen; Metalloporphyrins; Soret bands; Time dependent density functional theory; Asphaltenes; Bituminous materials; Continuum mechanics; Crude oil; Density functional theory; Heavy oil production; Nickel; Ultraviolet spectroscopy; Porphyrins

Magnetic gold nanoparticles as a vehicle for fluorescein isothiocyanate and DNA delivery into plant cells - Hao, Yuzhi; Yang, Xiaoyan; Shi, Yongzhong; Song, Steven; Xing, James; Marowitch, Janet; Chen, Jianmin; Chen, Jie (Botany, 2013)
Magnetic gold nanoparticles (mGNPs) with uniform size and morphology synthesized by our sonication treatment method were covalently bound with fluorescein isothiocyanate (FITC) molecules. Driven by an external magnetic field, FITC-labelled nanoparticles were delivered into plant cells with and without cell walls, evident from sectional transmission electron microscopy images. Confocal images further indicate that the green fluorescence in canola protoplasts and walled cells indeed came from the FITC molecules, instead of the chloroplasts' autofluorescence. FITC-labelled nanoparticles had a delivery efficiency of 95% based on confocal images. In further study, plasmids were covalently bound with mGNPs, and delivered into canola cells with and without cell walls. After culturing for 48 h followed by staining with 5-bromo-4-chloro-3-indolyl-β-D-glucuronic acid (X-Gluc), blue colour appeared in the protoplasts, while the walled canola cells showed a green colour that can be interpreted as the combination of blue and yellow from the suspension cells themselves. The presence of the blue colour indicates the expression of the GUS gene; therefore, the plasmids were successfully delivered into the canola cells. Furthermore, on examination, mGNPs were considered to be noncytotoxic by fluorescein diacetate staining.
Keywords: canola; DNA; gene expression; gold; image analysis; nanotechnology; plasmid

Understanding the effect of secondary structure on molecular interactions of poly-l-lysine with different substrates by SFA - Binazadeh, Mojtaba; Faghihnejad, Ali; Unsworth, Larry D.; Zeng, Hongbo (Biomacromolecules, 2013)
Nonspecific adsorption of proteins on biomaterial surfaces challenges the widespread application of engineered materials, and understanding the impact of secondary structure of proteins and peptides on their adsorption process is of both fundamental and practical importance in bioengineering. In this work, poly-l-lysine (PLL)-based α-helices and β-sheets were chosen as a model system to investigate the effect of secondary structure on peptide interactions with substrates of various surface chemistries. Circular dichroism (CD) was used to confirm the presence of both α-helix and β-sheet structured PLL in aqueous solutions and upon adsorption to quartz, where these secondary structures seemed to be preserved. Atomic force microscopy (AFM) imaging showed different surface patterns for adsorbed α-helix and β-sheet PLL. Interactions between PLL of different secondary structures and various substrates (i.e., PLL, Au, mica, and poly(ethylene glycol) (PEG)) were directly measured using a surface forces apparatus (SFA). It was found that β-sheet PLL films showed higher adsorbed layer thicknesses in general. Adhesion energies of β-sheet versus Au and β-sheet versus β-sheet were considerably higher than that of α-helix versus Au and α-helix versus α-helix systems, respectively. Au and β-sheet PLL interactions seemed to be more dependent on the salt concentration than that of α-helix, while the presence of a grafted PEG layer greatly diminished any attraction with either PLL structure. The molecular interaction mechanism of peptide in different secondary structures is discussed in terms of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, Alexander-de Gennes (AdG) steric model and hydrogen bonding, which provides important insight into the fundamental understanding of the interaction mechanism between proteins and biomaterials. © 2013 American Chemical Society.
Keywords: Biomaterial surfaces; Derjaguin-Landau-Verwey-Overbeek theories; Engineered materials; Interaction mechanisms; Nonspecific adsorption; Secondary structure of proteins; Secondary structures; Surface forces apparatus; Atomic force microscopy; Hydrogen bonds; Mica; Molecular interactions; Polyethylene glycols; Polyethylene oxides; Quartz; Gold; macrogol; alpha helix; atomic force microscopy; beta sheet; circular dichroism; concentration (parameters); protein interaction

Extended photometry for the DEEP2 Galaxy Redshift Survey: a testbed for photometric redshift experiments - Matthews, Daniel J.; Newman, Jeffrey A.; Coil, Alison L.; Cooper, Michael C.; Gwyn, Stephen D. J. (The Astrophysical Journal, Supplement Series, 2013)
This paper describes a new catalog that supplements the existing DEEP2 Galaxy Redshift Survey photometric and spectroscopic catalogs with ugriz photometry from two other surveys: the Canada-France-Hawaii Legacy Survey (CFHTLS) and the Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs. We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to provide a more uniform data set. We have also used this improved photometry to predict DEEP2 BRI photometry in regions where only poorer measurements were available previously. In addition, we have included improved astrometry tied to SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog contains ∼27, 000 objects with full ugriz photometry as well as robust spectroscopic redshift measurements, 64% of which have r > 23. By combining the secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz photometry, we have created a catalog that can be used as an excellent testbed for future photo-z studies, including tests of algorithms for surveys such as LSST and DES. © 2013. The American Astronomical Society. All rights reserved.

Kinematics of outer halo globular clusters in M31 - Veljanoski, J.; Ferguson, A. M. N.; MacKey, A. D.; Huxor, A. P.; Irwin, M. J.; Côté, P.; Tanvir, N. R.; Bernard, E. J.; Chapman, S. C.; Ibata, R. A.; Fardal, M.; Lewis, G. F.; et al. (The Astrophysical Journal Letters, 2013)
We present the first kinematic analysis of the far outer halo globular cluster (GC) population in the Local Group galaxy M31. Our sample contains 53 objects with projected radii of ∼20-130 kpc, 44 of which have no previous spectroscopic information. GCs with projected radii ≳ 30 kpc are found to exhibit net rotation around the minor axis of M31, in the same sense as the inner GCs, albeit with a smaller amplitude of 79 ± 19 km s-¹. The rotation-corrected velocity dispersion of the full halo GC sample is 106 ± 12 km s-¹, which we observe to decrease with increasing projected radius. We find compelling evidence for kinematic coherence among GCs that project on top of halo substructure, including a clear signature of infall for GCs lying along the northwest stream. Using the tracer mass estimator, we estimate the dynamical mass of M31 within 200 kpc to be M M31 = (1.2-1.5) ± 0.2 × 10¹#&178; M . This value is highly dependent on the chosen model and assumptions within. © 2013. The American Astronomical Society. All rights reserved..

Limits on Quaoar's atmosphere - Fraser, Wesley C.; Trujillo, Chad; Stephens, Andrew W.; Gimeno, German; Brown, Michael E.; Gwyn, Stephen; Kavelaars, J. J. (The Astrophysical Journal Letters, 2013)
Here we present high cadence photometry taken by the Acquisition Camera on Gemini South, of a close passage by the 540 km radius Kuiper belt object, (50000) Quaoar, of a r′ = 20.2 background star. Observations before and after the event show that the apparent impact parameter of the event was 0.″019 ± 0.″004, corresponding to a close approach of 580 ± 120 km to the center of Quaoar. No signatures of occultation by either Quaoar's limb or its potential atmosphere are detectable in the relative photometry of Quaoar and the target star, which were unresolved during closest approach. From this photometry we are able to put constraints on any potential atmosphere Quaoar might have. Using a Markov chain Monte Carlo and likelihood approach, we place pressure upper limits on sublimation supported, isothermal atmospheres of pure N2, CO, and CH4. For N2 and CO, the upper limit surface pressures are 1 and 0.7 μbar, respectively. The surface temperature required for such low sublimation pressures is 33 K, much lower than Quaoar's mean temperature of 44 K measured by others. We conclude that Quaoar cannot have an isothermal N2 or CO atmosphere. We cannot eliminate the possibility of a CH4 atmosphere, but place upper surface pressure and mean temperature limits of 138 nbar and 44 K, respectively. © 2013. The American Astronomical Society. All rights reserved.

PAndAS in the mist: the stellar and gaseous mass within the halos of M31 and M33 - Lewis, Geraint F.; Braun, Robert; McConnachie, Alan W.; Irwin, Michael J.; Ibata, Rodrigo A.; Chapman, Scott C.; Ferguson, Annette M. N.; Martin, Nicolas F.; Fardal, Mark; Dubinski, John; Widrow, Larry; MacKey, A. Dougal; et al. (The Astrophysical Journal, 2013)
Large-scale surveys of the prominent members of the Local Group have provided compelling evidence for the hierarchical formation of massive galaxies, revealing a wealth of substructure that is thought to be the debris from ancient and ongoing accretion events. In this paper, we compare two extant surveys of the M31-M33 subgroup of galaxies: the Pan-Andromeda Archaeological Survey of the stellar structure, and a combination of observations of the H I gaseous content, detected at 21 cm. Our key finding is a marked lack of spatial correlation between these two components on all scales, with only a few potential overlaps between stars and gas. The paucity of spatial correlation significantly restricts the analysis of kinematic correlations, although there does appear to be H I kinematically associated with the Giant Stellar Stream where it passes the disk of M31. These results demonstrate that different processes must significantly influence the dynamical evolution of the stellar and H I components of substructures, such as ram pressure driving gas away from a purely gravitational path. Detailed modeling of the offset between the stellar and gaseous substructures will provide a determination of the properties of the gaseous halos of M31 and M33. © 2013. The American Astronomical Society. All rights reserved.

Thermal plasma in the giant lobes of the radio galaxy Centaurus A - O'Sullivan, S. P.; Feain, I. J.; McClure-Griffiths, N. M.; Ekers, R. D.; Carretti, E.; Robishaw, T.; Mao, S. A.; Gaensler, B. M.; Bland-Hawthorn, J.; Stawarz, Ł. (The Astrophysical Journal, 2013)
We present a Faraday rotation measure (RM) study of the diffuse, polarized, radio emission from the giant lobes of the nearest radio galaxy, Centaurus A. After removal of the smooth Galactic foreground RM component, using an ensemble of background source RMs located outside the giant lobes, we are left with a residual RM signal associated with the giant lobes. We find that the most likely origin of this residual RM is from thermal material mixed throughout the relativistic lobe plasma. The alternative possibility of a thin-skin/boundary layer of magnetoionic material swept up by the expansion of the lobes is highly unlikely since it requires, at least, an order of magnitude enhancement of the swept-up gas over the expected intragroup density on these scales. Strong depolarization observed from 2.3 to 0.96 GHz also supports the presence of a significant amount of thermal gas within the lobes; although depolarization solely due to RM fluctuations in a foreground Faraday screen on scales smaller than the beam cannot be ruled out. Considering the internal Faraday rotation scenario, we find a thermal gas number density of ∼10-4 cm -3, implying a total gas mass of ∼1010 M ⊙ within the lobes. The thermal pressure associated with this gas (with temperature kT ∼ 0.5 keV, obtained from recent X-ray results) is approximately equal to the non-thermal pressure, indicating that over the volume of the lobes, there is approximate equipartition between the thermal gas, radio-emitting electrons, and magnetic field (and potentially any relativistic protons present). © 2013. The American Astronomical Society. All rights reserved.

X-ray groups of galaxies in the AEGIS deep and wide fields - Erfanianfar, G.; Finoguenov, A.; Tanaka, M.; Lerchster, M.; Nandra, K.; Laird, E.; Connelly, J. L.; Bielby, R.; Mirkazemi, M.; Faber, S. M.; Kocevski, D.; Cooper, M.; et al. (The Astrophysical Journal, 2013)
We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redshifts allow us to identify 100% of reliable sources, leading to a catalog of 52 galaxy groups. These groups span the redshift range z ∼ 0.066-1.544 and virial mass range M200 ∼ 1.34 × 10¹³-1.33 × 10¹⁴4. For the 49 extended sources that lie within DEEP2 and DEEP3 Galaxy Redshift Survey coverage, we identify spectroscopic counterparts and determine velocity dispersions. We select member galaxies by applying different cuts along the line of sight or in projected spatial coordinates. A constant cut along the line of sight can cause a large scatter in scaling relations in low-mass or high-mass systems depending on the size of the cut. A velocity-dispersion-based virial radius can cause a larger overestimation of velocity dispersion in comparison to an X-ray-based virial radius for low-mass systems. There is no significant difference between these two radial cuts for more massive systems. Independent of radial cut, an overestimation of velocity dispersion can be created in the case of the existence of significant substructure and compactness in X-ray emission, which mostly occur in low-mass systems. We also present a comparison between X-ray galaxy groups and optical galaxy groups detected using the Voronoi-Delaunay method for DEEP2 data in this field. © 2013. The American Astronomical Society. All rights reserved.

Search for high proper motion objects in the CFHTLS deep fields - Hu, Juei-Hwa; Richer, Harvey; Gwyn, Stephen D. J.; Ip, Wing-Huen (The Astrophysical Journal, 2013)
We present the results of a search for high proper motion white dwarfs in the deep survey of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The CFHTLS Deep Survey covers 4 deg2 in five filters (u*, g′, r′, i′, and z′). For the first and the fourth fields, we use data for a 5 year baseline from 2004 to 2009. For the second and the third fields, we have a 4 year baseline from 2004 to 2008. Proper motion selection is used to distinguish cool high-velocity white dwarfs from distant objects with similar blue colors such as compact faint galaxies and quasars. We discovered 44 white dwarf candidates brighter than g′ = 24 on the basis of their spectral energy distribution and reduced proper motions. We found one white dwarf candidate with effective temperature less than 4000 K. From its estimated tangential velocity of 31 km s-1 and a distance of 124 pc, it appears to be located in the thin or thick disk of the Galaxy. We also find five candidates having Teff between 4000 K and 5000 K. One candidate in D2 with effective temperature of 5000 K and tangential velocity of 190 km s-1 indicates that it could be in the thick disk or in the halo. The other four candidates are likely located in the thin disk because of their estimated distances and tangential velocity. © 2013. The American Astronomical Society. All rights reserved.

The three-dimensional structure of the m31 satellite system; Strong evidence for an inhomogeneous distribution of satellites - Conn, A. R.; Lewis, G. F.; Ibata, R. A.; Parker, Q. A.; Zucker, D. B.; McConnachie, A. W.; Martin, N. F.; Valls-Gabaud, D.; Tanvir, N.; Irwin, M. J.; Ferguson, A. M. N.; Chapman, S. C. (The Astrophysical Journal, 2013)

The photometric and kinematic structure of face-on disk galaxies. III. Kinematic inclinations from Hα velocity fields - Andersen, David R.; Bershady, Matthew A. (The Astrophysical Journal, 2013)
Using the integral field unit DensePak on the WIYN 3.5 m telescope we have obtained Hα velocity fields of 39 nearly face-on disks at echelle resolutions. High-quality, uniform kinematic data and a new modeling technique enabled us to derive accurate and precise kinematic inclinations with mean i kin = 23° for 90% of these galaxies. Modeling the kinematic data as single, inclined disks in circular rotation improves upon the traditional tilted-ring method. We measure kinematic inclinations with a precision in sin i of 25% at 20° and 6% at 30°. Kinematic inclinations are consistent with photometric and inverse Tully-Fisher inclinations when the sample is culled of galaxies with kinematic asymmetries, for which we give two specific prescriptions. Kinematic inclinations can therefore be used in statistical "face-on" Tully-Fisher studies. A weighted combination of multiple, independent inclination measurements yield the most precise and accurate inclination. Combining inverse Tully-Fisher inclinations with kinematic inclinations yields joint probability inclinations with a precision in sin i of 10% at 15° and 5% at 30°. This level of precision makes accurate mass decompositions of galaxies possible even at low inclination. We find scaling relations between rotation speed and disk-scale length identical to results from more inclined samples. We also observe the trend of more steeply rising rotation curves with increased rotation speed and light concentration. This trend appears to be uncorrelated with disk surface brightness. © 2013. The American Astronomical Society. All rights reserved..

Comprehensive hormone profiling of the developing seeds of four grain legumes - Slater, Susan M. H.; Yuan, Hai ying; Lulsdorf, Monika M.; Vandenberg, Albert; Zaharia, L. Irina; Han, Xiumei; Abrams, Suzanne R. (Plant Cell Reports, 2013)
Improvement of in vitro tissue and cell culture protocols in grain legumes such as embryo rescue, interspecific hybridization, and androgenesis requires an understanding of the types, activity, and balance of hormones within developing seeds. Towards this goal, the concentration of auxin, cytokinin, gibberellin, and abscisic acid (ABA) and their precursors and derivatives were measured in the developing seeds of field pea (Pisum sativum L.), chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.), and faba bean (Vicia faba L.) from 4 days after anthesis until 8 days after reaching maximum fresh weight. The importance of developmental context (developmental time and space) is demonstrated in both the differences and similarities between species for hormone profiles, especially with regard to cytokinin and ABA biosynthesis during the embryo formation. Auxin and its conjugates are significant during the pattern formation stage of all legumes; however, IAA-Asparagine appears important in the Vicieae species and its concentrations are greater than IAA from the globular stage of embryo development on in multi-seed fruits. Finally, the significance of non-polar gibberellins during lentil seed development is highlighted.
Keywords: Abscisic acid; Auxin; Chickpea; Cytokinin; seed development; Faba bean; Field pea; Gibberellin; lentil

Endogenous hormone profiles during early seed development of C. arietinum and C. anatolicum - Lulsdorf, Monika M.; Yuan, Hai Ying; Slater, Susan M. H.; Vandenberg, Albert; Han, Xiumei; Zaharia, L. Irina; Abrams, Suzanne R. (Plant Growth Regulation, 2013)
Cicer anatolicum, a perennial species, has ascochyta blight resistance superior to that found in the cultivated chickpea. However, hybridization barriers during early stages of embryo development curtail access to this trait. Since hormones play an essential role in early embryo development, we have determined the hormone profiles of 4-, 8-, and 12-day old seeds from a Canadian chickpea (Cicer arietinum L.) cv. CDC Xena, from Indian cvs. Swetha and Bharati, and from a perennial accession of C. anatolicum (PI 383626). Indole-3-acetic acid content peaked on day 4 in CDC Xena, on day 8 in both Indian cultivars but only on day 12 in C. anatolicum. The cytokinins, isopentenyladenosine (iPA) and trans zeatin riboside (tZR) were predominant in CDC Xena and Swetha seeds on day 4, whereas cis zeatin riboside was the major component in Bharati. In C. anatolicum, iPA maxed out on day 4 and tZR on day 12. The bioactive gibberellin GA1 spiked on day 4 in CDC Xena and Bharati, on day 8 in Swetha but only on day 12 in C. anatolicum. Eight-day old seeds had the highest abscisic acid content in the cultivars but spiked on day 12 in the perennial species. The hormone profiles of the perennial species showed delayed spikes in all four hormone groups indicating that there is a mismatch in the hormone requirements of the different embryos. Improving synchronization of early seed hormone profiles of cultivated and perennial chickpea should improve interspecific hybrid production.
Keywords: Abscisic acid; C. anatolicum; Chickpea; Gibberellin; Indole-3-acetic acid; Zeatin

Flicker effects on brain activity - Veitch, Jennifer A. (Lighting Design + Application (The magazine of the Illuminating Engineering Society of North America), 2013)
In the “bad old days” (25 and more years ago), most commercial and institutional interior lighting consisted of fluorescent lamps run on magnetic ballasts. This light source had an inherent flicker rate of 120 Hz in North America, where the mains AC supply operates at 60 Hz.

Are green buildings better buildings? New research - Newsham, Guy R.; Birt, Benjamen J.; Arsenault, Chantal; Thompson, Alexandra J. L.; Veitch, Jennifer A.; Mancini, Sandra; Galasiu, Anca D.; Gover, Bradford N.; Macdonald, Iain A.; Burns, Gregory J. (Canadian Journal of Green Building and Design, 2013)
Detailed post-occupancy evaluation research in office buildings suggest that, on average, green buildings do deliver better indoor environment quality and energy efficiency than otherwise similar conventional buildings
Keywords: green buildings; indoor environment quality; post-occupancy evaluation

Preferred chromaticity of color-tunable LED lighting - Dikel, Erhan E.; Burns, Gregory J.; Veitch, Jennifer A.; Mancini, Sandra; Newsham, Guy R. (LEUKOS, 2013)
Previous research has demonstrated that individual personal control over light level benefits individuals and organizations. As a first step toward testing whether light source spectrum choices—which are possible with light emitting diode (LED) systems—offer similar benefits, we examined preferences for various spectra in a scale model of an office. Participants judged the model’s brightness, colorfulness, and pleasantness when lit with five preset spectra with measured correlated color temperatures (CCTs) of 2855, 3728, 4751, 5769, and 6507 K created with five LED channels and one fluorescent spectrum (3750 K measured), all at approximately 500 lx. Then they chose their preferred light spectrum using the five LED channels, once as a free choice and once with an illuminance limit. Judgments of the fluorescent spectrum and the LED spectrum with the closest (matched) CCT did not differ. The preset judgments followed a quadratic pattern, with the lowest and highest CCT conditions having lower ratings than the three middle conditions. The free and illuminance-constrained lighting choices did not differ, with individuals’ selections ranging from 2850 to 14,000 K and generally lying slightly below the blackbody curve.
Keywords: Light-emitting diode; LED; ofice lighting; spectral tuning; colour tuning; personal preference; individual lighting control; colour quality metrics

Distributional semantics beyond words : supervised learning of analogy and paraphrase - Turney, Peter D. (Transactions of the Association for Computational Linguistics (TACL), 2013)
There have been several efforts to extend distributional semantics beyond individual words, to measure the similarity of word pairs, phrases, and sentences (briefly, tuples; ordered sets of words, contiguous or noncontiguous). One way to extend beyond words is to compare two tuples using a function that combines pairwise similarities between the component words in the tuples. A strength of this approach is that it works with both relational similarity (analogy) and compositional similarity (paraphrase). However, past work required hand-coding the combination function for different tasks. The main contribution of this paper is that combination functions are generated by supervised learning. We achieve state-of-the-art results in measuring relational similarity between word pairs (SAT analogies and SemEval 2012 Task 2) and measuring compositional similarity between nounmodifier phrases and unigrams (multiplechoice paraphrase questions).

Adaptation of reordering models for statistical machine translation - Chen, Boxing; Foster, George; Kuhn, Roland (Proceedings of the 2013 North America Chapter of the Association for Computational Linguistics : Human Language Technologies, 2013)
Previous research on domain adaptation (DA) for statistical machine translation (SMT) has mainly focused on the translation model (TM) and the language model (LM). To the best of our knowledge, there is no previous work on reordering model (RM) adaptation for phrasebased SMT. In this paper, we demonstrate that mixture model adaptation of a lexicalized RM can significantly improve SMT performance, even when the system already contains a domain-adapted TM and LM. We find that, surprisingly, different training corpora can vary widely in their reordering characteristics for particular phrase pairs. Furthermore, particular training corpora may be highly suitable for training the TM or the LM, but unsuitable for training the RM, or vice versa, so mixture weights for these models should be estimated separately. An additional contribution of the paper is to propose two improvements to mixture model adaptation: smoothing the in-domain sample, and weighting instances by document frequency. Applied to mixture RMs in our experiments, these techniques (especially smoothing) yield significant performance improvements.

Improved reordering for phrase-based translation using sparse features - Cherry, Colin (Proceedings of the NAACL, 2013)
There have been many recent investigations into methods to tune SMT systems using large numbers of sparse features. However, there have not been nearly so many examples of helpful sparse features, especially for phrasebased systems. We use sparse features to address reordering, which is often considered a weak point of phrase-based translation. Using a hierarchical reordering model as our baseline, we show that simple features coupling phrase orientation to frequent words or wordclusters can improve translation quality, with boosts of up to 1.2 BLEU points in Chinese-English and 1.8 in Arabic-English. We compare this solution to a more traditional maximum entropy approach, where a probability model with similar features is trained on wordaligned bitext. We show that sparse decoder features outperform maximum entropy handily, indicating that there are major advantages to optimizing reordering features directly for BLEU with the decoder in the loop.

We'll take it from here : letting the users take charge of the evaluation and why that turned out well - Munteanu, Cosmin; Fournier, Hélàne; Lapointe, Jean-François; Emond, Bruno; Kondratova, Irina (CHI '13 Extended Abstracts on Human Factors in Computing Systems, 2013)
The operational challenges faced by law enforcement and public safety personnel are constantly evolving, while the training and certification process has stayed the same. New technologies such as virtual reality, mixed reality, or game-based simulators are being researched as promising enhancements to traditional training methods. However, their widespread adoption, particularly by smaller units, faces barriers such as cost – due in no small part to the difficulties of developing and especially evaluating such large-scale interactive systems. In this case study, we present MINT – a lowcost mixed-reality Multimodal Interactive Training system, aimed at supporting the training of small- and medium-sized law enforcement and infantry units. We discuss the challenges and approaches taken in the participatory design of the training system, its agilebased development and implementation, and its qualitative evaluation with users and subject-matter experts.
Keywords: User studies; evaluation methodology; mixed-reality interaction; immersive gaming

Feature space selection and combination for native language identification - Goutte, Cyril; Léger, Serge; Carpuat, Marine (Proceedings of the 8th Workshop on Innovative Use of NLP for Building Educational Applications (BEA8), 2013)
We decribe the submissions made by the National Research Council Canada to the Native Language Identification (NLI) shared task. Our submissions rely on a Support Vector Machine classifier, various feature spaces using a variety of lexical, spelling, and syntactic features, and on a simple model combination strategy relying on a majority vote between classifiers. Somewhat surprisingly, a classifier relying on purely lexical features performed very well and proved difficult to outperform significantly using various combinations of feature spaces. However, the combination of multiple predictors allowed to exploit their different strengths and provided a significant boost in performance.

A kinematic study of the Andromeda dwarf spheroidal system - Collins, Michelle L. M.; Chapman, Scott C.; Rich, R. Michael; Ibata, Rodrigo A.; Martin, Nicolas F.; Irwin, Michael J.; Bate, Nicholas F.; Lewis, Geraint F.; Peñarrubia, Jorge; Arimoto, Nobuo; Casey, Caitlin M.; Ferguson, Annette M. N.; et al. (The Astrophysical Journal, 2013)

Stellar populations in compact galaxy groups: A multi-wavelength study of HCGs 16, 22, and 42, their star clusters, and dwarf galaxies - Konstantopoulos, I. S.; Maybhate, A.; Charlton, J. C.; Fedotov, K.; Durrell, P. R.; Mulchaey, J. S.; English, J.; Desjardins, T. D.; Gallagher, S. C.; Walker, L. M.; Johnson, K. E.; Tzanavaris, P.; et al. (The Astrophysical Journal, 2013)
We present a multi-wavelength analysis of three compact galaxy groups, Hickson compact groups (HCGs) 16, 22, and 42, which describe a sequence in terms of gas richness, from space- (Swift, Hubble Space Telescope (HST), and Spitzer) and ground-based (Las Campanas Observatory and Cerro Tololo Inter-American Observatory) imaging and spectroscopy. We study various signs of past interactions including a faint, dusty tidal feature about HCG 16A, which we tentatively age-date at <1 Gyr. This represents the possible detection of a tidal feature at the end of its phase of optical observability. Our HST images also resolve what were thought to be double nuclei in HCG 16C and D into multiple, distinct sources, likely to be star clusters. Beyond our phenomenological treatment, we focus primarily on contrasting the stellar populations across these three groups. The star clusters show a remarkable intermediate-age population in HCG 22, and identify the time at which star formation was quenched in HCG 42. We also search for dwarf galaxies at accordant redshifts. The inclusion of 33 members and 27 "associates" (possible members) radically changes group dynamical masses, which in turn may affect previous evolutionary classifications. The extended membership paints a picture of relative isolation in HCGs 16 and 22, but shows HCG 42 to be part of a larger structure, following a dichotomy expected from recent studies. We conclude that (1) star cluster populations provide an excellent metric of evolutionary state, as they can age-date the past epochs of star formation; and (2) the extended dwarf galaxy population must be considered in assessing the dynamical state of a compact group.

Anchors for the cosmic distance scale: the Cepheids U Sagittarii, CF Cassiopeiae, and CEab Cassiopeiae - Majaess, D.; Carraro, G.; Moni Bidin, C.; Bonatto, C.; Berdnikov, L.; Balam, D.; Moyano, M.; Gallo, L.; Turner, D.; Lane, D.; Gieren, W.; Borissova, J.; et al. (Astronomy and Astrophysics, 2013)
New and existing X-ray, UBVJHKsW(1 - 4), and spectroscopic observations were analyzed to constrain fundamental parameters for M 25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance because they host the classical Cepheids U Sgr, CF Cas, and the visual binary Cepheids CEa and CEb Cas. Precise results from the multiband analysis, in tandem with a comprehensive determination of the Cepheids' period evolution (dP/dt) from ~140 years of observations, helped to resolve concerns raised regarding the clusters and their key Cepheid constituents. Specifically, the distances derived for members of M 25 and NGC 7790 are 630 ± 25 pc and 3.40 ± 0.15 kpc, respectively.
Keywords: Distance scale; Hertzsprung-Russell and C-M diagrams; Multiband analysis; Star clusters; Stars: variables: Cepheids; Visual binaries

Investigation of the bubble formation in liquid cross-flow using a novel nozzle design - Jobehdar, Mona Hassanzadeh; Gadallah, Aly H.; Siddiqui, Kamran; Chishty, Wajid A. (ASME 2013 Fluids Engineering Division Summer Meeting, 2013)
Injection of bubbly gas flow into a liquid stream has wide application in chemical and biochemical industries. In these applications, generation of smaller bubble at higher frequency is desirable to achieve better reaction efficiency. We report on an experimental study conducted to investigate the bubble formation in liquid cross-flow using a novel nozzle design developed by Gadallah and Siddiqui [1]. This design is based on the creation of two side holes in the standard nozzle near the main nozzle hole. The experiments were performed in an acrylic square flow channel and high speed imaging was used to capture bubble dynamics. An image processing algorithm was used to quantify the size and frequency of detached bubbles and to track each individual bubble at different gas flow rates and liquid velocities. The results show that the new design of nozzle generates more bubbles of smaller size compared to the standard nozzle with no side hole at low liquid flow rates. It was observed that while the liquid velocity has crucial affect on the bubble size and detachment frequency from a standard nozzle, these parameters are weakly dependent on the liquid flow rate in the novel nozzle. The results show that at low liquid flow rates or in the stagnant liquid, the novel nozzle generates bubbles that are more than 20% smaller in size and more than two times faster compared to the standard nozzle. Copyright © 2013 by ASME and Her Majesty the Queen in Right of Canada.

Nanoscale optomechanical sensors: split-beam photonic crystal nanocavities - Hryciw, Aaron; Wu, Marcelo; Khanaliloo, Behzad; Healey, Christopher; Barclay, Paul E. (13th International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD 2013, 2013)
Optomechanical nanocavities allow nanomechanical resonances to be measured optically with high sensitivity. We have created a new type of photonic crystal nanocavity optomechanical sensor optimized for detecting sources of torque and other forces which can deflect nanoscale cantilevers. This nanocavity consists of two precisely engineered photonic Bragg mirrors patterned in silicon cantilevers and separated by a 50-100 nm wide gap. Simulations of the optical and mechanical modes predict that mechanical displacements of the sub-picogram cantilevers will shift the optical nanocavity resonance frequency at a rate exceeding 20 GHz / nm, and that the nanocavity optical mode may have a quality factor Qo > 10⁶in optimized devices.
Keywords: Mechanical displacements; Nanomechanical resonances; Nanoscale cantilevers; Opto-mechanical sensors; Photonic crystal nanocavities; Photonic crystal nanocavity; Resonance frequencies; Silicon cantilever; Computer simulation; Nanocantilevers; Nanotechnology; Numerical models; Optimization; Photonic crystals; Sensors; Optoelectronic devices

Integrated process of laser-assisted machining and laser surface heat treatment - Shi, B.; Attia, H. (Journal of Manufacturing Science and Engineering, Transactions of the ASME, 2013)
A process is proposed for integrating the laser-assisted machining (LAM) and laser surface heat treatment (LSHT) in a single operation. Experimental and numerical investigations were carried out. LSHT tests were performed to investigate the effect of the process parameters on the microstructure evolution and hardenability. A methodology and an empirical model for prediction of hardened depth were proposed. A two-dimensional finite element (2D-FE) model was developed to predict the phase transformation during the LAM and LSHT processes. The optimization of the LAM process was also investigated using the developed finite element model. Copyright © 2013 by ASME.
Keywords: Empirical model; Hardenability; Hardened depth; Laser surface heat treatments; Laser-assisted machining; Micro-structure evolutions; Numerical investigations; Process parameters; Finite element method; Microstructure; Laser beam welding

Wave-in-deck loads for an intricate pile-supported pier and variation with deck clearance - Cornett, A.; Anglin, D.; Elliott, T. (Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 2013)
Many deck structures are located at elevations low enough to be impacted by large waves. However, due to the highly complex and impulsive nature of the interactions between wave crests and intricate deck structures, establishing reliable estimates of extreme pressures and forces for use in design remains challenging. In this paper, results from an extensive set of three-dimensional scale model tests conducted to support the design of a large pile-supported pier (or jetty) are presented and discussed. Relationships between maximum wave-in-deck loads and the deck clearance (air gap) are presented and discussed. Results from numerical simulations of the wave-structure interaction process obtained using the three-dimensional CFD software FLOW-3D® are also presented and discussed. Finally, some initial comparisons between the numerical and physical modelling are also included. This paper provides new insights concerning the character and magnitude of the hydrodynamic pressures and loads exerted on intricate pile-supported deck structures due to impact by non-linear shallow-water waves, and the relationships between the hydrodynamic forcing and the deck clearance or air gap. Copyright © 2013 by ASME.

Comparative xylose metabolism among the ascomycetes C. albicans, S. stipitis and S. cerevisiae - Harcus, D.; Dignard, D.; Lépine, G.; Askew, C.; Raymond, M.; Whiteway, M.; Wu, C. (PLoS ONE, 2013)
The ascomycetes Candida albicans, Saccharomyces cerevisiae and Scheffersomyces stipitis metabolize the pentose sugar xylose very differently. S. cerevisiae fails to grow on xylose, while C. albicans can grow, and S. stipitis can both grow and ferment xylose to ethanol. However, all three species contain highly similar genes that encode potential xylose reductases and xylitol dehydrogenases required to convert xylose to xylulose, and xylulose supports the growth of all three fungi. We have created C. albicans strains deleted for the xylose reductase gene GRE3, the xylitol dehydrogenase gene XYL2, as well as the gre3 xyl2 double mutant. As expected, all the mutant strains cannot grow on xylose, while the single gre3 mutant can grow on xylitol. The gre3 and xyl2 mutants are efficiently complemented by the XYL1 and XYL2 from S. stipitis. Intriguingly, the S. cerevisiae GRE3 gene can complement the Cagre3 mutant, while the ScSOR1 gene can complement the Caxyl2 mutant, showing that S. cerevisiae contains the enzymatic capacity for converting xylose to xylulose. In addition, the gre3 xyl2 double mutant of C. albicans is effectively rescued by the xylose isomerase (XI) gene of either Piromyces or Orpinomyces, suggesting that the XI provides an alternative to the missing oxido-reductase functions in the mutant required for the xylose-xylulose conversion. Overall this work suggests that C. albicans strains engineered to lack essential steps for xylose metabolism can provide a platform for the analysis of xylose metabolism enzymes from a variety of species, and confirms that S. cerevisiae has the genetic potential to convert xylose to xylulose, although non-engineered strains cannot proliferate on xylose as the sole carbon source. © 2013 Boyles et al.

Carbon nanosheet frameworks derived from peat moss as high performance sodium ion battery anodes - Ding, J.; Wang, H.; Li, Z.; Kohandehghan, A.; Cui, K.; Xu, Z.; Zahiri, B.; Tan, X.; Lotfabad, E.M.; Olsen, B.C.; Mitlin, D. (ACS Nano, 2013)
We demonstrate that peat moss, a wild plant that covers 3% of the earth's surface, serves as an ideal precursor to create sodium ion battery (NIB) anodes with some of the most attractive electrochemical properties ever reported for carbonaceous materials. By inheriting the unique cellular structure of peat moss leaves, the resultant materials are composed of three-dimensional macroporous interconnected networks of carbon nanosheets (as thin as 60 nm). The peat moss tissue is highly cross-linked, being rich in lignin and hemicellulose, suppressing the nucleation of equilibrium graphite even at 1100 C. Rather, the carbons form highly ordered pseudographitic arrays with substantially larger intergraphene spacing (0.388 nm) than graphite (c/2 = 0.3354 nm). XRD analysis demonstrates that this allows for significant Na intercalation to occur even below 0.2 V vs Na/Na+. By also incorporating a mild (300 C) air activation step, we introduce hierarchical micro- and mesoporosity that tremendously improves the high rate performance through facile electrolyte access and further reduced Na ion diffusion distances. The optimized structures (carbonization at 1100 C + activation) result in a stable cycling capacity of 298 mAh g-1 (after 10 cycles, 50 mA g-1), with ∼150 mAh g-1 of charge accumulating between 0.1 and 0.001 V with negligible voltage hysteresis in that region, nearly 100% cycling Coulombic efficiency, and superb cycling retention and high rate capacity (255 mAh g -1 at the 210th cycle, stable capacity of 203 mAh g-1 at 500 mA g-1). © 2013 American Chemical Society.
Keywords: Carbonaceous materials; High-rate capacities; High-rate performance; Interconnected network; Lithium-ion battery; Optimized structures; pore; Sodium ion batteries; Anodes; Carbon; Carbonization; Graphene; Graphite; Lithium compounds; Metal ions; Nanosheets; Plants (botany); Peat

Characterization of phase transformations and stresses during the welding of a ferritic mild steel - Dye, D.; Stone, H.J.; Watson, M.; Rogge, R.B. (Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 2013)
The transient stresses and phase evolution have been characterized in the quasi-steady state produced around a gas tungsten arc welding torch in a plain carbon (ASTM 1018) steel using in situ neutron diffraction. A novel method has been developed to isolate the deviatoric or plane stress state in the presence of isotropic contributions to the lattice parameter, such as thermal expansion and solute content. The stress state was found to evolve in the anticipated manner, with compressive stresses ahead of the weld and tensile stresses behind the weld, in the weld and heat-affected zone, and compression in the far field behind the weld. In particular, the region of compression in the heat-affected zone adjacent to and just behind the welding torch expected from weld models was observed. The evolution of phase fraction around the weld was also determined using the technique and the stresses obtained from the ferrite phase. © 2013 The Minerals, Metals & Materials Society and ASM International.

Multiple roles of the transcription factor AtMYBR1/AtMYB44 in ABA signaling, stress responses, and leaf senescence - Jaradat, Masrur R.; Feurtado, J. Allan; Huang, Daiquing; Lu, Yongquan; Cutler, Adrian J. (BMC Plant Biology, 2013)
Background: The transcription factor AtMYBR1 (MYB44) is a member of the MYB family of transcription factors and is expressed throughout the plant life cycle and especially in senescing and wounded leaves. It has previously been shown to be involved in responses to abiotic stress and is regulated by phosphorylation.Results: When MYBR1 was over-expressed under the control of the constitutive 35S promoter in Arabidopsis thaliana (OxMYBR1), leaf senescence was delayed. In contrast loss-of-function mybr1 plants showed more rapid chlorophyll loss and senescence. The MYBR1 promoter strongly drove β-GLUCURONIDASE reporter gene expression in tissues immediately after wounding and many wounding/pathogenesis genes were downregulated in OxMYBR1. OxMYBR1 plants were more susceptible to injury under water stress than wildtype, which was correlated with suppression of many ABA inducible stress genes in OxMYBR1. Conversely, mybr1 plants were more tolerant of water stress and exhibited reduced rates of water loss from leaves. MYBR1 physically interacted with ABA receptor PYR1-LIKE8 (PYL8) suggesting a direct involvement of MYBR1 in early ABA signaling. MYBR1 appears to exhibit partially redundant functions with AtMYBR2 (MYB77) and double mybr1 X mybr2 mutants exhibited stronger senescence and stress related phenotypes than single mybr1 and mybr2 mutants.Conclusions: MYBR1 is a negative regulator of ABA, stress, wounding responses and blocks senescence. It appears to have a homeostatic function to maintain growth processes in the event of physical damage or stress.
Keywords: Arabidopsis thaliana; ABA; Drought stress; transcription factor; PYL8; Senescence

Bidirectional lipid droplet velocities are controlled by differential binding strengths of HCV core DII protein - Lyn, R.K.; Hope, G.; Sherratt, A.R.; McLauchlan, J.; Pezacki, J.P. (PLoS ONE, 2013)
Host cell lipid droplets (LD) are essential in the hepatitis C virus (HCV) life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein's lipid binding domain II (DII-core) induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV. Copyright: © 2013 Lyn et al.

Flow-field and conjugate heat transfer of an internally air-cooled nozzle guide vane and shrouds - Jiang, L. (Proceedings of the ASME Turbo Expo, 2013)
In order to assess the life of gas turbine critical components, it is essential to adequately specify their aero-thermodynamic working environments. Steady-state analyses of the flow field and conjugate heat transfer of an internally air-cooled nozzle guide vane (NGV) and shrouds of a gas turbine engine at the baseline operating conditions are numerically investigated. A high-fidelity CFD model is generated and the simulations are carried out with properly defined boundary conditions. The features of the complicated flow and temperature fields are revealed. In general, the Mach number is lower and the temperature is higher on the NGV pressure side than those on the suction side. There are two high temperature spots on the pressure side, and the temperature across the NGV middle section is relatively low. These findings are closely related to the locations of the holes and outlets of the cooling flow passage, and consistent with the field observation of damaged NGVs. The obtained results provide essential information for the structural, material and life analyses of the NGV/shrouds assembly, and improvement of the cooling flow arrangement. Copyright © 2013 by Her Majesty The Queen in Right of Canada.
Keywords: Conjugate heat transfer; Critical component; Field observations; High-fidelity CFD model; Nozzle guide vanes; Operating condition; Steady-state analysis; Working environment; Computer simulation; Cooling systems; Exhibitions; Rocket nozzles; Gas turbines

Correlation between intake and ingestive behavior of pasture-grazed heifers - Santana, H.A.; Silva, R.R.; Carvalho, G.G.P.; Silva, F.F.; Trindade Jr., G.; Pinheiro, A.A.; Rodrigues, E.S.O.; Filho, G.A.; Santana, E.O.C.; Mendes, F.B.L. (Semina:Ciencias Agrarias, 2013)
The objective of this study was to evaluate the correlation between intake and ingestive behavior of crossbred heifers in grazing tropical. The experiment was conducted on the Princesa do Mateiro Farm, in the city of Ribeirão do Largo, Bahia. A total of 20 heifers with genetic makeup 5/8 dairy Guzerá and 3/8 Holstein, average age of 18 months and body weight of 187 ± 13.1 kg have been used. The experiment lasted 224 days and involved animals raised in a rotational grazing system with Brachiaria brizantha cv. Marandú. Grazing time was not correlated with any of the variables associated with intake. Rumination time showed positive correlations with the intake of forage dry matter (DMIF) and neutral detergent fiber (NDFI). Variables associated with the time spent on feeding at the trough, overall feeding and total chewing were not correlated with intake (P>0.05). There have been positive correlations between the number of grazing periods (NGP) and rumination periods (NRP) and total DM intake (TDMI), organic matter (OMI), forage (DMIF), neutral detergent fiber (NDFI), total carbohydrates (TCHI) and ether extract (EEI). Crude protein intake (CPI) was positively correlated with NGP and NRP. The mouthful rate was positively correlated with TDMI, OMI, DMIF, NDFI, TCHI, EEI and CPI. Average time per swallow was negatively correlated with TDMI, OMI, NDFI, TCHI and EEI. Positive correlations have been observed between the number of mouthfuls per day and TDMI, OMI, DMIF, NDFI, TCHI, EEI. The number of chews per bolus showed negative correlations with DMIS and CPI. The time per cake ruminated has correlated negatively with the intake of crude protein. The number of chews per bolus showed positive correlations with the intakes of dry matter and neutral detergent fiber. The number of boli per day showed positive correlations with DMIF and TCHI. The time spent on chewing showed no significant correlation with intake. In conflict with the national and international literature, the grazing time was not correlated with intake by grass-fed crossbred heifers. The number of activities, the time spent on them and the mouthful rate where shown to be highly associated with the intake variables and can therefore arrange equations to predict intake through the analysis of feeding behavior. The number of mouthfuls performed each day contributes to the intake by pasture-grazed heifers.

Plant Acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs) have different specificities in their forward and reverse reactions - Lager, I.; Yilmaz, J.L.; Zhou, X.-R.; Jasieniecka, K.; Kazachkov, M.; Wang, P.; Zou, J.; Weselake, R.; Smith, M.A.; Bayon, S.; Dyer, J.M.; Shockey, J.M.; et al. (Journal of Biological Chemistry, 2013)
Background: Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) enzymes have central roles in acyl editing of phosphatidylcholine. Results: Plant LPCATs were expressed in yeast and biochemically characterized. Conclusion: LPCATs can edit acyl composition of phosphatidylcholine through their combined forward and reverse reactions. Significance: Plant LPCATs play a role in editing both sn-positions of PC and remove ricinoleic acid with high selectivity from this lipid. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.
Keywords: Acyl-CoA; Acyltransferase; Acyltransferases; High selectivity; Phosphatidylcholine; Reverse reactions; Ricinoleic acid; Biochemistry; Biology

The relationship between energy separation and base drag in turbine blade wakes - Gostelow, J.P.; Carscallen, W.E; Kurosaka, M.; Mahallati, A. (Proceedings of the ASME Turbo Expo, 2013)
During annular cascade testing of a highly-loaded turbine stage of aggressive design, the nozzle blading experienced a redistribution of the downstream total temperature field. In this ostensibly adiabatic arrangement, the central regions of the vane wakes exhibited a significant decrease in total temperature and their edges showed an unexpected increase. To resolve these anomalous results and obtain detailed information over the Mach number range, the mid-span section of the nozzle was tested in a large scale transonic planar cascade. At high subsonic speeds, vortex shedding created energy redistribution in the wake. This was measured using an 80 kHz bandwidth temperature probe, making it possible to investigate wake total temperature fluctuations in addition to fluctuations in total pressure, and hence entropy. 'Hot spots' of increased total temperature were found to be located at the edge of the wake and 'cold spots' of decreased total temperature were located close to the wake center line. The results from the turbine cascade were consistent with the phenomenon of energy separation behind bluff bodies. High base pressure losses were observed and were also related to the vortex shedding. The blade had a thick trailing edge and the high base pressure loss condition coincided with the peak of energy separation in the wake. The analysis indicates that in the subsonic speed range the phenomena of energy separation and of base pressure deficit are inextricably linked to, and are caused by, vortex shedding. A strategy for minimizing the related adverse impacts on performance is outlined. Copyright © 2013 by ASME.
Keywords: Aggressive designs; Annular cascades; Energy re distributions; Energy separations; Peak of energies; Planar cascades; Temperature probes; Total temperatures; Exhibitions; Gas turbines; Nozzle design; Nozzles; Separation; Subsonic aerodynamics; Vortex shedding; Wakes

Photoluminescence efficiency of self-assembled germanium dots - Lockwood, D.J.; Rowell, N.L.; Barbagiovanni, E.G.; Goncharova, L.V.; Simpson, P.J.; Berbezier, I.; Amiard, G.; Favre, L.; Ronda, A.; Faustini, M.; Grosso, D. (SPIE - International Society for Optical Engineering. Proceedings, 2013)
Under the proviso that the existing tight-binding (TB) and effective mass (EM) theoretical models provide a good description of the Ge dot energy gap versus dot diameter, this work investigates the effect of nanoparticle size and the size distribution on the near infrared PL spectrum obtained from self-assembled Ge dots grown on a thin layer of TiO2 or SiO2 on Si. For the as-grown samples, the dot PL emission occupies a wide near-infrared band between 0.8 and 1 eV. The PL efficiency versus dot size for four samples was obtained in three steps. Firstly, the PL spectrum was converted to an intensity plot versus dot diameter rather than energy by taking the PL emission from each dot to occur at the dot bandgap calculated using the TB or EM model. Secondly, a numerical form for the physical size distribution of that sample was obtained by performing a least-squares fit of a Gaussian to the dot size distribution measured by atomic force microscopy or transmission electron microscopy. Finally, the PL efficiency versus dot size was calculated using the fitted Gaussian dot size distribution to normalize the PL intensity distribution obtained in the first step. Although the absolute intensities of the PL from the samples vary, the calculated curves are all well-fitted by straight lines on a log-log plot with essentially the same slope for all samples, which indicates that under weak confinement there is a universal power-law increase in PL efficiency with decreasing dot size. © 2013 SPIE.
Keywords: Absolute intensity; Dots; Effective-mass; Nanoparticle sizes; Near-infrared bands; Photoluminescence efficiency; Theory; Tight binding; Atomic force microscopy; Binding energy; Efficiency; Energy gap; Infrared devices; Photoluminescence; Photonics; Silica; Size distribution; Transmission electron microscopy; Germanium

Solvent exchange in sulphoaluminate phases. Part I: Ettringite - Khoshnazar, R.; Beaudoin, J.; Raki, L.; Alizadeh, R. (Advances in Cement Research, 2013)
The change in the microstructure of ettringite and concomitant changes in volume due to the application of organic solvent exchange methods were investigated. Ettringite samples conditioned to 11% relative humidity were treated with methanol, ethanol and iso-propanol, and were examined using different analytical techniques (x-ray diffraction, Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy and nitrogen BET surface area measurement) to explore the limitations of using these organic solvents in the study of ettringite microstructure. The results suggest that methanol interacts with ettringite and therefore is not recommended for characterisation of this sulphoaluminate phase. Ethanol and iso-propanol did not significantly change the crystalline structure of ettringite, but did result in a higher surface area of the treated sample compared with the surface area of the untreated one. The length-change of ettringite in these alcohols was also determined and the results are presented.

G2C2 - II. Integrated colour-metallicity relations for Galactic globular clusters in SDSS passbands - Vanderbeke, J.; West, M.J.; De Propris, R.; Peng, E.W.; Blakeslee, J.P.; Jordán, A.; Ĉoté, P.; Gregg, M.; Ferrarese, L.; Takamiya, M.; Baes, M. (Monthly Notices of the Royal Astronomical Society, 2013)
We use our integrated Sloan Digital Sky Survey (SDSS) photometry for 96 globular clusters in g and z, as well as r and i photometry for a subset of 56 clusters, to derive the integrated colour- metallicity relation (CMR) for Galactic globular clusters.We compare this relation to previous work, including extragalactic clusters, and examine the influence of age, present-day mass function variations, structural parameters and the morphology of the horizontal branch on the relation. Moreover, we scrutinize the scatter introduced by foreground extinction (including differential reddening) and show that the scatter in the CMR can be significantly reduced combining two reddening laws from the literature. In all CMRs, we find some low-reddening young GCs that are offset to the CMR. Most of these outliers are associated with the Sagittarius system. Simulations show that this is due to less age than to a different enrichment history. Finally, we introduce CMRs based on the infrared calcium triplet, which are clearly non-linear when compared to (g′ - i′) and (g′ - z′) colours. © 2013 The Authors.

Energy-selective optical excitation and detection in InAs/InP quantum dot ensembles using a one-dimensional optical microcavity - Gamouras, A.; Britton, M.; Khairy, M.M.; Mathew, R.; Dalacu, D.; Poole, P.; Poitras, D.; Williams, R.L.; Hall, K.C. (Applied Physics Letters, 2013)
We demonstrate the selective optical excitation and detection of subsets of quantum dots (QDs) within an InAs/InP ensemble using a SiO2/Ta 2O5-based optical microcavity. The low variance of the exciton transition energy and dipole moment tied to the narrow linewidth of the microcavity mode is expected to facilitate effective qubit encoding and manipulation in a quantum dot ensemble with ease of quantum state readout relative to qubits encoded in single quantum dots. © 2013 AIP Publishing LLC.
Keywords: Exciton transition energy; InAs/InP quantum dots; Microcavity modes; Narrow-line width; Optical microcavities; Quantum dot ensemble; Quantum state; Single quantum dot; Microcavities; Photoexcitation; Quantum computers; Quantum theory; Semiconductor quantum dots; Tantalum oxides; Quantum optics

Distance and age of the pulsar wind nebula 3C 58 - Kothes, R. (Astronomy and Astrophysics, 2013)
Context. A growing number of researchers present evidence that the pulsar wind nebula 3C 58 is much older than predicted by its proposed connection to the historical supernova of A.D. 1181. There is also a great diversity of arguments. The strongest of these arguments rely heavily on the assumed distance of 3.2 kpc determined with H i absorption measurements. Aims. This publication aims at determining a more accurate distance for 3C 58 and at re-evaluating the arguments for an older age. Methods. I have re-visited the distance determination of 3C 58 based on new H i data from the Canadian Galactic Plane Survey and our recent improvements in the knowledge of the rotation curve of the outer Milky Way Galaxy. I also used newly determined distances to objects in the neighbourhood, which are based on direct measurements by trigonometric parallax. Results. I have derived a new more reliable distance estimate of 2 kpc for 3C 58. This makes the connection between the pulsar wind nebula and the historical event from A.D. 1181 once again much more viable. © 2013 ESO.
Keywords: Absorption measurements; Canadian galactic plane surveys; Direct measurement; Distance determination; ISM: individual objects; ISM: supernova remnants; Pulsar wind nebula; Pulsars: individuals; Geometrical optics; Stars; Galaxies

Neutrino and axion bounds from the globular cluster M5 (NGC 5904) - Viaux, N.; Catelan, M.; Stetson, P.B.; Raffelt, G.G.; Redondo, J.; Valcarce, A.A.R.; Weiss, A. (Physical Review Letters, 2013)
The red-giant branch (RGB) in globular clusters is extended to larger brightness if the degenerate helium core loses too much energy in "dark channels." Based on a large set of archival observations, we provide high-precision photometry for the Galactic globular cluster M5 (NGC 5904), allowing for a detailed comparison between the observed tip of the RGB with predictions based on contemporary stellar evolution theory. In particular, we derive 95% confidence limits of gae<4.3×10-13 on the axion-electron coupling and μν<4.5×10 -12μB (Bohr magneton μB=e/2me) on a neutrino dipole moment, based on a detailed analysis of statistical and systematic uncertainties. The cluster distance is the single largest source of uncertainty and can be improved in the future. © 2013 American Physical Society.
Keywords: Bohr magnetons; Confidence limit; Globular clusters; High-precision; Stellar evolutions; Systematic uncertainties; Elementary particles; Uncertainty analysis

Endoscopic third ventriculostomy on a microneurosurgery simulator - Jiang, Di; Hovdebo, Jordan; Cabral, Anne; Mora, Vincent; Delorme, Sébastien (Simulation, 2013)
Endoscopic third ventriculostomy is a procedure used to treat hydrocephalus by making a perforation in the floor of the third ventricle of the brain under endoscopic guidance. We report on our initial experience in developing an endoscopic third ventriculostomy simulator for neurosurgery residents, including the definition of the simulation content and integration on NeuroTouch, a simulator for microneurosurgery training. The simulator includes exercises in which the trainee is asked to choose the location of the burr hole and the orientation of the trajectory to the foramen of Monro, or is required to find the third ventricle with a neuro-endoscope and perforate its floor. The simulator provides feedback on trainee performance either graphically or using quantitative metrics. The simulator allows easily switching from endoscopic third ventriculostomy mode to microscopic craniotomy mode using a retractable stereoscope based on a single screen and mirrors, detachable plastic heads, and quick-connect tool handles to give more realistic haptic feedback. © 2013 National Research Council Canada, Crown copyright.
Keywords: Haptic feedbacks; Neuro-endoscopy; Quantitative metrics; Single screen; Ventriculostomy; Virtual endoscopy; Computer simulation; Floors; Neurosurgery; Personnel training; Photography; Simulators; Virtual reality; Endoscopy

High output power, fibre-coupled distributed feedback lasers operating near 2.05 μm wavelength range - Bagheri, M.; Frez, C.; Kelly, B.; Gupta, J.A.; Forouhar, S. (Electronics Letters, 2013)
Single-mode operation of fibre-pigtailed distributed feedback semiconductor lasers in the 2.05 μm range has been demonstrated. The lasers are packaged inside standard butterfly modules with output powers in excess of 10 mW at the end of polarisation maintaining optical fibre. The fibre-pigtailed lasers show excellent sidemode suppression ratios ( > 50 dB) and have a mode-hop free tunability larger than 1 nm. The output of the optical fibre has linear polarisation with better than 20 dB extinction over the operating current and temperatures. © The Institution of Engineering and Technology 2013.
Keywords: Distributed feedback semiconductor laser; High output power; Linear polarisation; Operating currents; Side mode suppression ratios; Single mode operation; Tunabilities; Wavelength ranges; Polarization-maintaining fiber; Distributed feedback lasers

Solvent exchange in sulfoaluminate phases. Part II: Monosulfate - Khoshnazar, R.; Beaudoin, J.; Raki, L.; Alizadeh, R. (Advances in Cement Research, 2013)
The influence of organic solvent exchange techniques on the microstructure and the dimensional stability of monosulfate (3CaO.Al2O 3.CaSO4.12H2O) was critically investigated. Monosulfate samples were treated with methanol, ethanol and isopropanol, and examined by different analytical techniques including X-ray diffraction, Fourier transform infrared spectroscopy, thermal gravimetric analysis and scanning electrom microscopy. Nitrogen surface area measurements (Brunauer-Emmett-Teller (BET) method) and length-change of the monosulfate samples in the solvents were also recorded. Evidence was obtained that indicates monosulfate was readily dehydrated from 12 water molecules to ten water molecules once it was treated by the investigated alcohols. The alcohol molecules, however, likely intercalated into the monosulfate structure, limiting an expected decrease in the interlayer distance of the monosulfate structure. Methanol had the greatest damaging effect on the monosulfate microstructure. Ethanol, however, resulted in higher long-term expansion owing to its intermediate molecular size and reactivity with monosulfate compared to methanol and isopropanol.

A novel approach to control thermal degradation of PET/organoclay nanocomposites and improve clay exfoliation - Ghanbari, A.; Heuzey, M.C.; Carreau, P.J.; Ton-That, M.T. (Polymer (United Kingdom), 2013)
Thermal degradation of polyethylene terephthalate (PET) is accelerated in the presence of commercial organoclays, and this remains a challenge for the industry. While a high level of clay delamination is required in polymer nanocomposites, thermal degradation increases furthermore for highly exfoliated morphologies due to an increased exposure of the polymer matrix to silicate nanoplatelets. In this work, two different types of organomodified clay were melt blended with PET in the presence of a multifunctional epoxy-based chain extender, Joncryl® ADR-4368F (Joncryl), to compensate for molecular weight reduction during processing. The chain extender was added via a master-batch approach in order to promote clay delamination before molecular weight increase. The morphological, rheological, mechanical, thermal, and gas barrier characteristics of the nanocomposites were studied using several characterization techniques. A remarkable improvement in viscoelastic properties was observed for samples containing the chain extender due to recoupling of degraded chains. A better clay dispersion, enhanced barrier properties and increased Young modulus were also obtained for nanocomposites containing the chain extender. Compared to neat PET films, the oxygen permeability of nanocomposite films containing 4 wt% Cloisite® 30B and 1 wt% Joncryl decreased by 46%, whereas the corresponding permeability decrease for the Nanomer® I.28E nanocomposite was 40%. A 66% improvement in Young modulus was obtained for nanocomposite films containing 4 wt% Nanomer® I.28E and 1 wt% Joncryl. The improvement of the tensile modulus for the corresponding Cloisite® 30B nanocomposite was slightly less. © 2012 Elsevier Ltd. All rights reserved.
Keywords: Barrier properties; Chain extenders; Characterization techniques; Clay delamination; Clay dispersion; Clay exfoliation; Cloisite; Gas barrier; Nano-platelets; Organoclays; Organomodified clay; Oxygen permeability; PET films; Polymer nanocomposite; Recoupling; Viscoelastic properties; Young modulus; Delamination; Molecular weight; Nanocomposites; Polyethylene terephthalates; Silicates; Nanocomposite films

Water and methanol maser survey of protostars in the orion molecular cloud complex - Kang, M.; Lee, J.-E.; Choi, M.; Choi, Y.; Kim, K.-T.; Di Francesco, J.; Park, Y.-S. (Astrophysical Journal, Supplement Series, 2013)
The results of a maser survey toward 99 protostars in the Orion molecular cloud complex are presented. The target sources are low-mass protostars identified from infrared observations. Single-dish observations were carried out in the water maser line at 22 GHz and the methanol class I maser lines at 44, 95, and 133 GHz. Most of the detected sources were mapped to determine the source positions. Five water maser sources were detected, and they are excited by HH 1-2 VLA 3, HH 1-2 VLA 1, L1641N MM1/3, NGC 2071 IRS 1/3, and an object in the OMC 3 region. The water masers showed significant variability in intensity and velocity with time scales of 1 month or shorter. Four methanol emission sources were detected, and those in the OMC 2 FIR 3/4 and L1641N MM1/3 regions are probably masers. The methanol emission from the other two sources in the NGC 2071 IRS 1-3 and V380 Ori NE regions are probably thermal. For the water masers, the number of detections per protostar in the survey region is about 2%, which suggests that the water masers of low-mass protostars are rarely detectable. The methanol class I maser of low-mass protostars is an even rarer phenomenon, with a detection rate much smaller than 1%. © 2013. The American Astronomical Society. All rights reserved.

Comparison of solid oxide fuel cell stack performance using detailed and simplified models - Nishida, R.T.; Beale, S.B.; Pharoah, J.G. (ASME 2013 11th Int. Conf. on Fuel Cell Science, Eng. and Technology Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 7th Int. Conf. on Energy Sustainability, FUELCELL 2013, 2013)
Two computational fluid dynamics models have been developed to predict the performance of a solid oxide fuel cell stack, a detailed and a simplified model. In the detailed model, the three dimensional momentum, heat, and species transport equations are coupled with electrochemistry. In the simplified model, the diffusion terms in the transport equations are selectively replaced by rate terms within the core region of the stack. This allows much coarser meshes to be employed at a fraction of the computational cost. Following the mathematical description of the problem, results for a single cell and multi-cell stack are presented. Comparisons of local current density, temperature, and cell voltage indicate that good agreement is obtained between the detailed and simplified models, confirming the validity of the latter as a practical option in stack design. Copyright © 2013 by ASME.

Pillars and globules at the edges of H ii regions: Confronting Herschel observations and numerical simulations - Tremblin, P.; Minier, V.; Schneider, N.; Audit, E.; Hill, T.; Didelon, P.; Peretto, N.; Arzoumanian, D.; Motte, F.; Zavagno, A.; Bontemps, S.; Anderson, L.D.; et al. (Astronomy and Astrophysics, 2013)
Context. Herschel far-infrared imaging observations have revealed the density structure of the interface between H ii regions and molecular clouds in great detail. In particular, pillars and globules are present in many high-mass star-forming regions, such as the Eagle nebula (M 16) and the Rosette molecular cloud, and understanding their origin will help characterize triggered star formation. Aims. The formation mechanisms of these structures are still being debated. The initial morphology of the molecular cloud and its turbulent state are key parameters since they generate deformations and curvatures of the shell during the expansion of the H ii region. Recent numerical simulations have shown how pillars can arise from the collapse of the shell in on itself and how globules can be formed from the interplay of the turbulent molecular cloud and the ionization from massive stars. The goal here is to test this scenario through recent observations of two massive star-forming regions, M 16 and the Rosette molecular cloud. Methods. First, the column density structure of the interface between molecular clouds and associated H ii regions was characterized using column density maps obtained from far-infrared imaging of the Herschel HOBYS key programme. Then, the DisPerSe algorithm was used on these maps to detect the compressed layers around the ionized gas and pillars in different evolutionary states. Column density profiles were constructed. Finally, their velocity structure was investigated using CO data, and all observational signatures were tested against some distinct diagnostics established from simulations. Results. The column density profiles have revealed the importance of compression at the edge of the ionized gas. The velocity properties of the structures, i.e. pillars and globules, are very close to what we predict from the numerical simulations. We have identified a good candidate of a nascent pillar in the Rosette molecular cloud that presents the velocity pattern of the shell collapsing on itself, induced by a high local curvature. Globules have a bulk velocity dispersion that indicates the importance of the initial turbulence in their formation, as proposed from numerical simulations. Altogether, this study re-enforces the picture of pillar formation by shell collapse and globule formation by the ionization of highly turbulent clouds. © ESO, 2013.
Keywords: H II regions; ISM: individual objects; Ism: individual objects: rosettes; ISM: Kinematics and dynamics; ISM: structure; Methods:observational; Computer simulation; Gases; Infrared imaging; Ionization of gases; Numerical models; Shells (structures); Stars; Velocity; Clouds

Ultra-fast dynamic imaging of matter - Staudte, A. (Journal of Modern Optics, 2013)

Stress intensity factor solution for cracks in panels with arbitrarily located stringers - Bombardier, Y.; Liao, M.; Renaud, G. (Journal of Aircraft, 2013)
This paper presents a stress intensity factor solution for cracks located in panels reinforced with arbitrarily located stringers. The new solution was developed by modifying the constitutive equations of a solution for symmetrically and periodically spaced stringers with riveted rigid fasteners. The new solution supports arbitrary stringer locations with respect to the crack location, includes the capability to model compliant fasteners, improves the accuracy of the equivalent stringer compliance by considering Poisson's effect, and allows the fasteners to be arbitrarily located within each stringer. For the tested cases, the difference between the stress intensity factors calculated using the new closed-form solution and the linear static finite-element analysis results were within 4%. Through two examples for the CC-130 aircraft, it was shown that the closed-form solution developed for a center crack in an infinite sheet could also be used to model an edge crack growing in a relatively large panel. © 2012 AIAA.

Simultaneous determination of Co, Fe, Ni and Pb in carbon nanotubes by means of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry - Resano, Martin; Bolea-Fernández, Eduardo; Mozas, Engracia; Flórez, Maria R.; Grinberg, Patricia; Sturgeon, Ralph E. (Journal of Analytical Atomic Spectrometry, 2013)
This work explores the possibilities of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry for the direct analysis of carbon nanotubes. In particular, the simultaneous determination of Co, Fe, Ni and Pb is intended, as these elements are typically found in these samples as impurities. The results demonstrate that it is possible to find spectral (monitoring of the region between 283.168 and 283.481 nm), furnace (2500 °C for atomization; use of 100 ng Pd as a chemical modifier) and detector (use of side pixels to expand the linear range) conditions that permit the development of a fast and straightforward method for the simultaneous determination of the target elements at the levels at which they are typically found (mg g-1 for Co, Fe and Ni; μg g-1 for Pb) in carbon nanotubes. Limits of detection of 23 pg (Pb), 6 ng (Fe), 65 ng (Ni) and 86 ng (Co) were obtained, which are suitable for this type of sample. In this way, it was feasible to carry out the analysis of the samples investigated (one candidate reference material and three commercially available samples) and achieve accurate results when constructing the calibration curve with aqueous standards. Precision values for 5 solid sample replicates varied between 7 and 15% RSD in most cases. Overall, the proposed method shows important benefits for the cost-effective analysis of such complex samples in routine labs. This journal is © The Royal Society of Chemistry.
Keywords: Calibration curves; Candidate reference materials; Chemical modifiers; Cost-effective analysis; Graphite furnace atomic absorption spectrometry; Limits of detection; Simultaneous determinations; Straight-forward method; Carbon nanotubes; Lead; Nickel; Iron compounds

Electrochemical behaviours of titanium nitride (TIN) and chromium nitride (CRN) based pvd coating systems - Cai, F.; Huang, X.; Yang, Q. (Proceedings of the ASME Turbo Expo, 2013)
Hard coatings applied to steel components prevent corrosion attacks while at the same time mitigate erosion attack. However, the presence of process related through-coating defects such as pin holes, voids and growth defects, provides accesses for corrosive media to metal substrates, initializing pitting corrosion and eventually resulting in coating failure. This research studies the corrosion behavior of PVD TiN and CrN (CrSiCN) coated steels in 3.5 wt. % NaCl aqueous solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results revealed that in a coating-substrate system, effective diffusion coefficient and diffusion layer thickness control the corrosion resistance; both factors are found to be related to coating microstructure. A denser and thicker coating structure are shown to have lower effective diffusion coefficients and greater effective diffusion layer thicknesses and consequently provided a high resistance to electrochemical corrosion. Copyright © 2013 by ASME.
Keywords: Coating microstructures; Coating-substrate systems; Diffusion layer thickness; Effective diffusion coefficients; EIS; Electrochemical behaviour; NaCl aqueous solution; PVD coatings; Corrosion; Corrosion resistance; Defects; Diffusion; Diffusion coatings; Electrochemical impedance spectroscopy; Exhibitions; Gas turbines; Hard coatings; Pitting; Potentiodynamic polarization; Titanium nitride; Electrochemical corrosion

Genomics of seed development: Challenges and opportunities for genetic improvement of seed traits in crop plants - Venglat, P.; Xiang, D.; Wang, E.; Datla, R. (Biocatalysis and Agricultural Biotechnology, 2013)
Seed development represents an important phase in the life cycle of flowering plants including the majority of the crop plants. During this phase, developmental and metabolic programs are coordinated to produce the seed that contains the germline information and storage reserves. Although seed developmental patterns vary significantly between the monocots and dicots, they share several conserved developmental programs. The embryo is the major component of the seed in dicots whereas the endosperm is predominant in monocot seeds. The formation of the dormant seed that protects the embryo and provides nutrition during germination is a key characteristic adaptive feature in the evolution of the angiosperms and a determining factor of yield in crop plants. From a crop perspective, the metabolites and especially the storage products deposited in the seed defines the value of the seed. Despite progress in fundamental understanding of seed development, the global genetic and metabolic programs involved in the making of the seed and their implications to genetic improvement of the seed is yet to be fully exploited in crop plants. So, the major goal of several recent studies is to develop comprehensive systems-level insights into molecular and biochemical programs associated with gene expression, protein and metabolite profiles during seed development in model and crop plants. These integrated systems approaches and studies are producing foundational and comprehensive datasets. In this review, we will present an overview of advances in the developmental, genetic and genomic studies of seed biology and their implications to improve seed characteristics in crop plants. Crown Copyright © 2013.

High-level expression of sugar inducible gene2 (HSI2) is a negative regulator of drought stress tolerance in Arabidopsis - Sharma, N.; Bender, Y.; Boyle, K.; Fobert, P.R. (BMC Plant Biology, 2013)
Background: HIGH-LEVEL EXPRESSION OF SUGAR INDUCIBLE GENE2 (HSI2), also known as VAL1, is a B3 domain transcriptional repressor that acts redundantly with its closest relative, HSI2-LIKE1 (HSL1), to suppress the seed maturation program following germination. Mutant hsi2 hsl1 seedlings are arrested early in development and differentially express a number of abiotic stress-related genes. To test the potential requirement for HSI2 during abiotic stress, hsi2 single mutants and plants overexpressing HSI2 were subjected to simulated drought stress by withholding watering, and characterized through physiological, metabolic and gene expression studies.Results: The hsi2 mutants demonstrated reduced wilting and maintained higher relative water content than wild-type after withholding watering, while the overexpressing lines displayed the opposite phenotype. The hsi2 mutant displayed lower constitutive and ABA-induced stomatal conductance than wild-type and accumulated lower levels of ABA metabolites and several osmolytes and osmoprotectants following water withdrawal. Microarray comparisons between wild-type and the hsi2 mutant revealed that steady-state levels of numerous stress-induced genes were up-regulated in the mutant in the absence of stress but down-regulated at visible wilting. Plants with altered levels of HSI2 responded to exogenous application of ABA and a long-lived ABA analog, but the hsi2 mutant did not show altered expression of several ABA-responsive or ABA signalling genes 4 hr after application.Conclusions: These results implicate HSI2 as a negative regulator of drought stress response in Arabidopsis, acting, at least in part, by regulating transpirational water loss. Metabolic and global transcript profiling comparisons of the hsi2 mutant and wild-type plants do not support a model whereby the greater drought tolerance observed in the hsi2 mutant is conferred by the accumulation of known osmolytes and osmoprotectants. Instead, data are consistent with mutants experiencing a relatively milder dehydration stress following water withdrawal. © 2013 Crown copyright; licensee BioMed Central Ltd.

Dynamic positioning simulation of a simplified FPSO in waves - Zhan, D.; Very, S.; Bass, D.; Millan, J. (Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 2013)
This paper presents a numerical station-keeping simulation in waves (regular and irregular waves) for a simplified FPSO with two DP systems. The main difference of the simulation with these two DP systems was that the first DP system (called MOT DP in this paper) was included in a seakeeping simulation code (MOTSIM) while another DP system (called IOT DP, developed by NRC/IOT) was an external system and installed on another computer (which was the same as the one used to control the vessel in physical model experiments). In order to exchange command messages between the simulation code (MOTSIM) and the IOT DP system, a communication code executed in the same time step was developed by using Windows™ socket functions. By using these two DP systems a station-keeping simulation for a 1:40 scale model FPSO with six azimuthing thrusters was conducted in regular and irregular waves and wind. The seakeeping RAO results in regular waves were compared between these two DP systems, and also with physical model experiments with external IOT DP system and analysis using a commercial linear, 3-dimensional panel code, HydroStar. In irregular waves a mean station keeping force Fx, Fy in horizontal plane was calculated and its total mean force was compared with results from the physical model experiments. Finally, a discussion between these two DP systems was provided. Copyright © 2013 by ASME.

Pre-symptomatic activation of antioxidant responses and alterations in glucose and pyruvate metabolism in niemann-pick type C1-deficient murine brain - Kennedy, B.E.; LeBlanc, V.G.; Mailman, T.M.; Fice, D.; Burton, I.; Karakach, T.K.; Karten, B. (PLoS ONE, 2013)
Niemann-Pick Type C (NPC) disease is an autosomal recessive neurodegenerative disorder caused in most cases by mutations in the NPC1 gene. NPC1-deficiency is characterized by late endosomal accumulation of cholesterol, impaired cholesterol homeostasis, and a broad range of other cellular abnormalities. Although neuronal abnormalities and glial activation are observed in nearly all areas of the brain, the most severe consequence of NPC1-deficiency is a near complete loss of Purkinje neurons in the cerebellum. The link between cholesterol trafficking and NPC pathogenesis is not yet clear; however, increased oxidative stress in symptomatic NPC disease, increases in mitochondrial cholesterol, and alterations in autophagy/mitophagy suggest that mitochondria play a role in NPC disease pathology. Alterations in mitochondrial function affect energy and neurotransmitter metabolism, and are particularly harmful to the central nervous system. To investigate early metabolic alterations that could affect NPC disease progression, we performed metabolomics analyses of different brain regions from age-matched wildtype and Npc1 -/- mice at pre-symptomatic, early symptomatic and late stage disease by 1H-NMR spectroscopy. Metabolic profiling revealed markedly increased lactate and decreased acetate/acetyl-CoA levels in Npc1-/- cerebellum and cerebral cortex at all ages. Protein and gene expression analyses indicated a presymptomatic deficiency in the oxidative decarboxylation of pyruvate to acetyl-CoA, and an upregulation of glycolytic gene expression at the early symptomatic stage. We also observed a pre-symptomatic increase in several indicators of oxidative stress and antioxidant response systems in Npc1 -/- cerebellum. Our findings suggest that energy metabolism and oxidative stress may present additional therapeutic targets in NPC disease, especially if intervention can be started at an early stage of the disease. © 2013 Kennedy et al.

Calculations of narrow-band transimissities and the Planck mean absorption coefficients of real gases using line-by-line and statistical narrow-band models - Chu, H.; Gu, M.; Zhou, H.; Liu, F. (Frontiers in Energy, 2013)
Narrow-band transmissivities in the spectral range of 150 to 9300 cm-1 and at a uniform resolution of 25 cm-1 were calculated using the statistical narrow-band (SNB) model with the band parameters of Soufiani and Taine, the more recent parameters of André and Vaillon, and the line-by-line (LBL) method along with the HITEMP-2010 spectroscopic database. Calculations of narrow-band transmissivity were conducted for gas columns of different lengths and containing different isothermal and non-isothermal CO2-H2O-N2 mixtures at 1 atm. Narrow-band transmissivities calculated by the SNB model are in large relative error at many bands. The more recent SNB model parameters of André and Vaillon are more accurate than the earlier parameters of Soufiani and Taine. The Planck mean absorption coefficients of CO2, H2O, CO, and CH4 in the temperature range of 300 to 2500 K were calculated using the LBL method and different versions of the high resolution transmission (HITRAN) and high-temperature spectroscopic absorption parameters (HITEMP) spectroscopic databases. The SNB model was also used to calculate the Planck mean absorption coefficients of these four radiating gases. The LBL results of the Planck mean absorption coefficient were compared with the classical results of Tien and those from the SNB model. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Framework for evaluation of the relative contribution of the process on porosity-cutting force dependence in micromilling of titanium foams - Fakhri, M.A.; Bordatchev, E.V.; Tutunea-Fatan, O.R. (Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2013)
Porous titanium, characterized by interconnected and large open-cell structures, constitutes one of the most promising bone substitutes that are currently available for surgical orthopedic and dental implantation procedures. Since little is known about the behavior of this highly porous material during material removal operations, the main objective of this study was to develop a framework capable of evaluating the effect of cutting speed, cutting depth, and feed rate on the interplay between porosity and cutting force signatures, as experienced during microslot cutting experiments. The comparisons performed between optically determined porosity and cutting force profiles by means of standard random data analysis metrics (correlation coefficient, power spectral density, and coherence) revealed that the presence of a material discontinuity has a prevalent effect on cutting force variation in the case of micromilling processes characterized by (1) less intensive machining regimes and (2) larger cutter/workpiece engagement zones. The proposed methodology is useful in selection of the investigative approach to be taken in assessment of the micromachining-related behavior of highly porous foams subjected to micromilling operations. © IMechE 2013.
Keywords: Cutting forces; Micro milling; Porous titanium; Process parameters; Random data analysis; Micromachining; Milling (machining); Porosity; Porous materials; Power spectral density; Titanium; Cutting

Engineering the optical properties of silicon using sub-wavelength structures - Halir, R.; Ortega-Moñux, A.; Maese-Novo, A.; Pérez-Galacho, D.; Zavargo-Peche, L.; Molina-Fernández, I.; Pérez, J.G.W.; Cheben, P.; Schmid, J.H.; Xu, D.-X.; Janz, S.; Fédéli, J.-M. (IEEE International Conference on Group IV Photonics GFP, 2013)
In most integrated optics platforms, including silicon-on-insulator, only minor modifications in refractive index are possible. The geometry of the waveguiding structure is thus the only degree of freedom for the design of devices. The use of sub-wavelength gratings (SWGs), i.e. structures that are small enough to suppress diffraction effects, enables local engineering of both refractive index and dispersion, thereby opening new possibilities for device design. Here we present some of the recent advances in refractive index and dispersion engineering using silicon SWGs, focussing on ultra-broadband and compact multimode interference couplers and directional couplers. © 2013 IEEE.
Keywords: Degree of freedom; Diffraction effects; Dispersion engineering; Multimode interference couplers; Sub-wave length grating; Sub-wavelength structures; Ultra-broadband; Waveguiding structures; Dispersion (waves); Dispersions; Photonics; Silicon; Refractive index

Detection and discrimination of motion-defined form: Implications for the use of night vision devices - Allison, R.S.; Macuda, T.; Jennings, S. (IEEE Transactions on Human-Machine Systems, 2013)
Superimposed luminance noise is typical of imagery from devices used for low-light vision such as image intensifiers (i.e., night vision devices). In four experiments, we measured the ability to detect and discriminate motion-defined forms as a function of stimulus signal-to-noise ratio at a variety of stimulus speeds. For each trial, observers were shown a pair of image sequences- one containing dots in a central motion-defined target region that moves coherently against the surrounding dots, which moved in the opposite or in random directions, while the other sequence had the same random/uniform motion in both the center and surrounding parts. They indicated which interval contained the target stimulus in a two-interval forced-choice procedure. In the first experiment, simulated night vision images were presented with Poisson-distributed spatiotemporal image noise added to both the target and surrounding regions of the display. As the power of spatiotemporal noise was increased, it became harder for observers to detect the target, particularly at the lowest and highest dot speeds. The second experiment confirmed that these effects also occurred with low illumination in real night vision device imagery, a situation that produces similar image noise. The third experiment demonstrated that these effects generalized to Gaussian noise distributions and noise created by spatiotemporal decorrelation. In the fourth experiment, we found similar speed-dependent effects of luminance noise for the discrimination (as opposed to detection) of the shape of a motion-defined form. The results are discussed in terms of physiological motion processing and for the usability of enhanced vision displays under noisy conditions. © 2013 IEEE.

Raman based detection of Staphylococcus aureus utilizing single domain antibody coated nanoparticle labels and magnetic trapping - Drake, P.; Jiang, P.-S.; Chang, H.-W.; Su, S.-C.; Tanha, J.; Tay, L.-L.; Chen, P.; Lin, Y.-J. (Analytical Methods, 2013)
Nanoparticle labels were used to detect the pathogenic bacteria Staphylococcus aureus. Two different labels were employed. These consisted of nanoparticles based on iron-oxide for magnetic trapping and isolation of the bacteria and surface enhanced Raman spectroscopy (SERS) active gold nanoparticles (AuNPs) coated with 4-mercaptobenzoic acid for the detection and quantification of the bacteria. Both types of nanoparticles were conjugated with single domain antibodies that selectively bind to protein A on the surface of S. aureus. Transmission electron microscopy (TEM) image analysis showed the iron-oxide nanoparticles to have magnetic core diameters of 20 nm ± 3 nm and the gold nanoparticles to be 51 nm ± 2 nm in diameter. A response curve was obtained displaying a logarithmic dependency between the 1073 cm -1 peak intensity in the SERS spectra of the AuNPs and the concentration of S. aureus cells in the initial sample. The overall detection limit was estimated to be 1 S. aureus cell mL-1 in less than 10 min without culturing. © 2013 The Royal Society of Chemistry.
Keywords: 4-mercaptobenzoic acids; Coated nanoparticles; Detection and quantifications; Gold Nanoparticles; Pathogenic bacterium; Single-domain antibodies; Staphylococcus aureus; Surface enhanced Raman spectroscopy; Antibodies; Bacteria; Chemical detection; Gold; Iron oxides; Metal nanoparticles; Raman spectroscopy; Transmission electron microscopy; Nanomagnetics

Continuous anaerobic bioreactor with a fixed-structure bed (ABFSB) for wastewater treatment with low solids and low applied organic loading content - Mockaitis, G.; Pantoja, J.L.R.; Rodrigues, J.A.D.; Foresti, E.; Zaiat, M. (Bioprocess and Biosystems Engineering, 2013)
This paper describes a new type of anaerobic bioreactor with a fixed-structure bed (ABFSB) in which the support for the biomass consists of polyurethane foam strips placed along the length of the bioreactor. This configuration prevents the accumulation of biomass or solids in the bed as well as clogging and channeling effects. In this study, complex synthetic wastewater with a chemical oxygen demand of 404.4 mg O2 L-1 is treated by the reactor. The ABFSB, which has a working volume of 4.77 L, was inoculated with anaerobic sludge obtained from an upflow anaerobic sludge blanket bioreactor. A removal efficiency of 78 % for organic matter and an effluent pH of 6.97 were achieved. An analysis of the organic volatile acids produced by the ABFSB indicated that it operated under stable conditions during an experimental run of 36 days. The stable and efficient operation of the bioreactor was compared with the configurations of other anaerobic bioreactors used for complex wastewater treatment. The results of the study indicate that the ABFSB is a technological alternative to packed-bed bioreactors. © 2013 Springer-Verlag Berlin Heidelberg.

Historical perspective: Neon interatomic potentials from scattering data and crystalline properties [Volume 19, Issue 3, 1 April 1973, Pages 359-362] - Farrar, J.M.; Lee, Y.T.; Goldman, V.V.; Klein, M.L. (Chemical Physics Letters, 2013)

Analytical modeling of oxide thickness variation of metals under high temperature solid-particle erosion - Chen, J.; Chen, K.; Liu, R.; Liang, M. (International Journal of Modeling, Simulation, and Scientific Computing, 2013)
The paper presents a study of model development for predicting the oxide thickness on metals under high temperature solid-particle erosion. The model is created based on the theory of solid-particle erosion that characterizes the erosion damage as deformation wear and cutting wear, incorporating the effect of the oxide scale on the eroded surface under high temperature erosion. Then the instantaneous oxide thickness is the result of the synergetic effect of erosion and oxidation. The developed model is applied on a Ni-based Al-containing (Ni-Al) alloy to investigate the oxide thickness variation with erosion duration of the alloy at high temperatures. The results show that the thickness of the oxide scale on the alloy surface increases with the exposure time and temperature when the surface is not attacked by particles. However, when particles impact on the alloy surface, the oxide thickness is reduced, although oxidation is continuing. This indicates that oxidation does not benefit the erosion resistance of this alloy at high temperatures due to the low growth rate of the oxide. © 2014 World Scientific Publishing Company.

From photons to phonons and back: A THz optical memory in diamond - England, D.G.; Bustard, P.J.; Nunn, J.; Lausten, R.; Sussman, B.J. (Physical Review Letters, 2013)
Optical quantum memories are vital for the scalability of future quantum technologies, enabling long-distance secure communication and local synchronization of quantum components. We demonstrate a THz-bandwidth memory for light using the optical phonon modes of a room temperature diamond. This large bandwidth makes the memory compatible with down-conversion-type photon sources. We demonstrate that four-wave mixing noise in this system is suppressed by material dispersion. The resulting noise floor is just 7×10-3 photons per pulse, which establishes that the memory is capable of storing single quanta. We investigate the principle sources of noise in this system and demonstrate that high material dispersion can be used to suppress four-wave mixing noise in Λ-type systems. Published by the American Physical Society.
Keywords: Local synchronizations; Material dispersions; Optical phonon modes; Physical societies; Quantum technologies; Room temperature; Secure communications; Single quantum; Four wave mixing; Optical communication; Phonons; Photons; Quantum cryptography; Dispersions

Reduce, reuse and recycle: A green solution to Canada's medical isotope shortage - Galea, R.; Ross, C.; Wells, R.G. (Applied Radiation and Isotopes, 2013)
Due to the unforeseen maintenance issues at the National Research Universal (NRU) reactor at Chalk River and coincidental shutdowns of other international reactors, a global shortage of medical isotopes (in particular technetium-99m, Tc-99m) occurred in 2009. The operation of these research reactors is expensive, their age creates concerns about their continued maintenance and the process results in a large amount of long-lived nuclear waste, whose storage cost has been subsidized by governments. While the NRU has since revived its operations, it is scheduled to cease isotope production in 2016. The Canadian government created the Non-reactor based medical Isotope Supply Program (NISP) to promote research into alternative methods for producing medical isotopes. The NRC was a member of a collaboration looking into the use of electron linear accelerators (LINAC) to produce molybdenum-99 (Mo-99), the parent isotope of Tc-99m. This paper outlines NRC's involvement in every step of this process, from the production, chemical processing, recycling and preliminary animal studies to demonstrate the equivalence of LINAC Tc-99m with the existing supply. This process stems from reusing an old idea, reduces the nuclear waste to virtually zero and recycles material to create a green solution to Canada's medical isotope shortage. Crown Copyright © 2013.

Optimization of stress-induced pockels effect in silicon waveguides for optical modulators - Aleali, Alireza; Xu, Danxia; Schmid, Jens H.; Cheben, Pavel; Ye, Winnie N. (IEEE International Conference on Group IV Photonics GFP, 2013)
A method for the optimization of strain-induced Pockels effect in silicon waveguides is proposed. We introduce a new figure of merit and show a 35% enhancement in FOM compared to most efficient reported devices. © 2013 IEEE.
Keywords: Electrooptic effects; Figure of merits; Pockels effect; Silicon waveguide; Stress-induced; Light modulators; Modulators; Photonics; Silicon; Strain; Waveguides; Optimization

Multipodal and multilayer TiO2 nanotube arrays: Hierarchical structures for energy harvesting and sensing - Mohammadpour, A.; Farsinezhad, S.; Hsieh, L.-H.; Shankar, K. (2013 MRS Spring Meeting - Symposium S – Nanostructured Metal Oxides for Advanced Applications, 2013)
Our ability to fabricate multipodal and multilayer TiO2 nanotube arrays enables us to increase performance and functionality in light harvesting devices such as excitonic solar cells and photocatalysts. Using a combination of simulations and experiments, we show that multilayer nanotube arrays enable photon management in the active toward enhancing the absorption and utilization of incident light. We show that the simultaneous utilization of TiO2 nanotubes with large (∼450 nm) and small (∼80 nm) diameters in stacked multilayer films increased light absorption and photocurrent in solar cells. Such enhanced light absorption is particularly desirable in the near-infrared region of the solar spectrum in which most excitonic solar cells suffer from poor quantum efficiencies and for blue photons at the TiO2 band-edge where significant room exists for improvement of photocatalytic quantum yields. Under AM 1.5 one sun illumination, multilayer nanotube arrays afforded us an approximately 20% improvement in photocurrent over single layer nanotube array films of the same thickness for N-719 sensitized liquid junction solar cells. Also, the possibility of multipodal TiO2 nanotube growth with different electrolyte recipes is presented. © 2013 Materials Research Society.

Rolling silver nanowire electrodes: Simultaneously addressing adhesion, roughness, and conductivity - Hauger, T.C.; Al-Rafia, S.M.I.; Buriak, J.M. (ACS Applied Materials and Interfaces, 2013)
Silver nanowire mesh electrodes represent a possible mass-manufacturable route toward transparent and flexible electrodes for plastic-based electronics such as organic photovoltaics (OPVs), organic light emitting diodes (OLEDs), and others. Here we describe a route that is based upon spray-coated silver nanowire meshes on polyethylene terephthalate (PET) sheets that are treated with a straightforward combination of heat and pressure to generate electrodes that have low sheet resistance, good optical transmission, that are topologically flat, and adhere well to the PET substrate. The silver nanowire meshes were prepared by spray-coating a solution of silver nanowires onto PET, in air at slightly elevated temperatures. The as-prepared silver nanowire electrodes are highly resistive due to the poor contact between the individual silver nanowires. Light pressure applied with a stainless steel rod, rolled over the as-sprayed silver nanowire meshes on PET with a speed of 10 cm s-1 and a pressure of 50 psi, results in silver nanowire mesh arrays with sheet resistances of less than 20 Ω/□. Bending of these rolled nanowire meshes on PET with different radii of curvature, from 50 to 0.625 mm, showed no degradation of the conductivity of the electrodes, as shown by the constant sheet resistance before and after bending. Repeated bending (100 times) around a rod with a radius of curvature of 1 mm also showed no increase in the sheet resistance, demonstrating good adherence and no signs of delamination of the nanowire mesh array. The diffuse and direct transmittance of the silver nanowires (both rolled and as-sprayed) was measured for wavelengths from 350 to 1200 nm, and the diffuse transmission was similar to that of the PET substrate; the direct transmission decreases by about 7-8%. The silver nanowires were then incorporated into OPV devices with the following architecture: transparent electrode/PEDOT:PSS/P3HT:PC61BM/LiF/Al. While slightly lower in efficiency than the standard indium tin oxide substrate (ITO), the rolled silver nanowire electrodes had a very good device yield, showing that short circuits resulting from the silver nanowire electrodes can be successfully avoided by this rolling approach. © 2013 American Chemical Society.
Keywords: Diffuse transmission; Indium tin oxide substrates; Organic light emitting diodes(OLEDs); Organic photovoltaics; Polyethylene terephthalates (PET); Silver nanowires; Spray coating; Transparent electrode; Adhesion; Coatings; Electric conductivity; Flexible electronics; Heat resistance; Nanowires; Organic light emitting diodes (OLED); Rolling; Sheet resistance; Topology; Transparency; Electrodes

Rapid determination of silicone oil lubricant in elastomeric closures by ICP-OES - dos Santos, Éder José; Herrmann, Amanda Beatriz; Sturgeon, Ralph Edward; Azevedo Silva, Jessee Severo; Curtius, Adilson José (Analytical Methods, 2013)
A rapid method for determination of silicone oil in elastomeric closures of injection syringes by inductively coupled plasma optical emission spectrometry (ICP-OES) is presented. The silicone oil was extracted from the intact closure using a mixture of methyl isobutyl ketone and 1-pentanol, no further sample treatment was necessary. Quantitation was based on response from Si(i) at 288.158 nm using external calibration with standard solutions of silicone oil dissolved in the same extraction mixture. A supplemental flow of oxygen was used to decrease background interference, providing a detection limit (3s, n = 10) of 0.05 mg of silicone per L. The LOQ (10s, n = 10) was 0.15 mg silicone per L, equivalent to 3.8 μg silicone/sample of elastomeric closure, based on 25 mL of extraction solvent per closure. The same samples were also analyzed by high-resolution flame atomic absorption spectrometry (HR-CS F-AAS), providing results similar to those obtained by ICP-OES. Spike recoveries of 97-104% demonstrated the accuracy of the methodology. Precision, expressed as the relative standard deviation, was 0.7-3.0% under conditions of repeatability and 0.7-3.3% for reproducibility. This simple procedure has been adopted by the Institute of Technology of Paraná-TECPAR (Curitiba, Brazil). © 2013 The Royal Society of Chemistry.
Keywords: External calibration; Extraction mixtures; Extraction solvents; Flame atomic absorption spectrometry; Inductively coupled plasma-optical emission spectrometry; Methyl iso-butyl ketones; Relative standard deviations; Standard solutions; Atomic absorption spectrometry; Extraction; Inductively coupled plasma; Interference suppression; Ketones; Mixtures; Optical emission spectroscopy; Silicones

G2C2 - I. Homogeneous photometry for galactic globular clusters in SDSS passbands - Vanderbeke, J.; West, M.J.; De Propris, R.; Peng, E.W.; Blakeslee, J.P.; Jordán, A.; Côté, P.; Gregg, M.; Ferrarese, L.; Takamiya, M.; Baes, M. (Monthly Notices of the Royal Astronomical Society, 2013)
We present g′ and z′ aperture photometry for 96 Galactic globular clusters, making this the largest homogeneous catalogue of photometry for these objects in the Sloan Digital Sky Survey (SDSS) filter system. For a subset of 56 clusters, we also provide photometry in r′ and i′. We carry out comparisons with previous photometry as well as with the SDSS data set. The data will be useful for a series of applications in Galactic and extragalactic astrophysics. Future papers will analyse the colour-metallicity relation, colour-magnitude diagrams and structural parameters. The compilation of results based on this data set will be collected in the Galactic Globular Cluster Catalog (G2C2). © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Assessment and characterization of volcanic ash threat to gas turbine engine performance - Davison, C.R.; Rutke, T. (Proceedings of the ASME Turbo Expo, 2013)
Multiple volcanoes erupt yearly propelling volcanic ash into the atmosphere and creating an aviation hazard. The plinian eruption type is most likely to create a significant aviation hazard. Plinian eruptions can eject large quantities of fine ash up to an altitude of 50,000 m (164,000 feet). While large airborne particles rapidly fall, smaller particles at reduced concentrations drift for days to weeks as they gradually descend and deposit on the ground. Very small particles, less than 1μm, can remain aloft for years. An average of three aircraft encounters with volcanic ash was reported every year between 1973 and 2003. Of these, 8 resulted in some loss of engine power, including a complete shutdown of all four engines on a Boeing 747. However, no crashes have been attributed to volcanic ash. The major forms of engine damage caused by volcanic ash are: 1. Deposition of ash on turbine nozzles and blades due to glassification 2. Erosion of compressor and turbine blades 3. Carbon deposits on fuel nozzles The combination of these effects can push the engine to surge and flame out. If a flame out occurs, engine restart may be possible. Less serious engine damage can also occur. In most cases the major damage will require an engine overhaul long before the minor damage becomes an operational issue, but under some conditions no sign of volcanic ash is evident and the turbine cooling system blockage could go unnoticed until an engine inspection is performed. Several organizations provide aircrew procedures to respond to encounters with a volcanic ash cloud. If a volcanic ash encounter is suspected, then an engine inspection, including borescope, should be performed with particular attention given to the turbine cooling system. Copyright © 2013 by Her Majesty the Queen in Right of Canada.
Keywords: Airborne particle; Aircraft encounters; Carbon deposites; Engine inspection; Operational issues; Plinian eruption; Turbine cooling systems; Volcanic ash clouds; Aircraft accidents; Aviation; Cooling systems; Deposits; Engines; Exhibitions; Gas turbines; Hazards; Nozzles; Thermoelectric equipment; Turbomachine blades; Volcanoes

Physical-layer security with multiuser scheduling in cognitive radio networks - Zou, Y.; Wang, X.; Shen, W. (IEEE Transactions on Communications, 2013)
In this paper, we consider a cognitive radio network that consists of one cognitive base station (CBS) and multiple cognitive users (CUs) in the presence of multiple eavesdroppers, where CUs transmit their data packets to CBS under a primary user's quality of service (QoS) constraint while the eavesdroppers attempt to intercept the cognitive transmissions from CUs to CBS. We investigate the physical-layer security against eavesdropping attacks in the cognitive radio network and propose the user scheduling scheme to achieve multiuser diversity for improving the security level of cognitive transmissions with a primary QoS constraint. Specifically, a cognitive user (CU) that satisfies the primary QoS requirement and maximizes the achievable secrecy rate of cognitive transmissions is scheduled to transmit its data packet. For the comparison purpose, we also examine the traditional multiuser scheduling and the artificial noise schemes. We analyze the achievable secrecy rate and intercept probability of the traditional and proposed multiuser scheduling schemes as well as the artificial noise scheme in Rayleigh fading environments. Numerical results show that given a primary QoS constraint, the proposed multiuser scheduling scheme generally outperforms the traditional multiuser scheduling and the artificial noise schemes in terms of the achievable secrecy rate and intercept probability. In addition, we derive the diversity order of the proposed multiuser scheduling scheme through an asymptotic intercept probability analysis and prove that the full diversity is obtained by using the proposed multiuser scheduling. © 2013 IEEE.
Keywords: Achievable secrecy rates; Cognitive base stations; Cognitive radio network; Cognitive transmissions; Diversity order; Multiuser scheduling; Physical-layer securities; Quality of Service constraints; Cognitive radio; Electric circuit breakers; Probability; Quality of service; Radio systems; Rayleigh fading; Scheduling

Carded recycled carbon fiber mats for the production of thermoset composites via infusion/compression molding - Andjelic, S.; Roberge, J.; Legros, N.; Khoun, L.; Schougaard, S.B. (SAE Technical Papers, 2013)
The use of carbon fiber reinforced thermoset composites has doubled in the last decade raising questions about the waste generated from manufacturing and at end-of-life, especially in the aircraft industry. In this study, 2.5 cm long carbon fibers were recovered from thermoset composite waste using a commercial scale pyrolysis process. Scanning electron microscopy, density measurements, single filament tensile testing as well as micro-droplet testing were performed to characterize the morphology, mechanical properties, and surface adhesion of the fibers. The recycled fibers appeared to be mostly undamaged and clean, exhibiting comparable mechanical properties to virgin carbon fibers. A carding process followed by an ultrasound treatment produced randomly aligned recycled fiber mats. These mats were used to fabricate composite plates, with fiber volume fractions up to 40 %, by infusion / compression molding. The mechanical properties of the plates were evaluated by tensile and flexural testing, and were found to be comparable to an equivalent containing virgin carbon fibers. Copyright © 2013 SAE International.
Keywords: Aircraft industries; Carbon fiber reinforced; Composite plates; Fiber volume fractions; Flexural testing; Pyrolysis process; Thermoset composites; Ultrasound treatments; Exhibitions; Fibers; Mechanical properties; Molding; Pyrolysis; Recycling; Scanning electron microscopy; Tensile testing; Textile industry; Thermosets; Carbon fibers

Carbon nanotube modified optical fiber surface plasmon resonance sensor - Zhang, Yang; Jakubinek, Michael; Simard, Benoit; Albert, Jacques (2013 IEEE Photonics Conference, IPC 2013, 2013)
Single-wall carbon nanotube deposition on gold-coated plasmonic optical fiber sensors has been proposed and demonstrated. The effects of carbon nanotubes on the polarization-dependent coupling of light from the fiber to the coating and on the resulting refractometric sensor properties are experimentally investigated. © 2013 IEEE.

Reduced-scale experimental research on fires in tunnels with natural ventilation - Yuan, Z.; Lei, B.; Kashef, A. (Procedia Engineering, 2013)
The 1/15 reduced-scale experiments were conducted using the Froude number conservation to investigate smoke diffusion characteristics in tunnel fires with natural ventilation. The effects of some factors such as: heat release rate, shaft distance, shaft size, train blockage and smoke curtain were studied. A porous bed propane burner, placed on the tunnel floor, was used to simulate the fire source. A series of K-type thermocouples were used to measure tunnel ceiling smoke temperatures. A hotwire anemometer was used to measure smoke volume rate and smoke temperature in the ventilation shaft. The experimental results indicated that all factors, except for the smoke curtain, have no major effect on the dimensionless ceiling temperatures in the fire section of the tunnel. Moreover, the fire size and train blockage do not have a significant effect on the dimensionless ceiling temperatures in the non-fire section of the tunnel. Nevertheless, the dimensionless ceiling temperatures in the non-fire section of the tunnel decreased with the decrease of the shaft distance and the increase of the shaft size. When the smoke curtain is used in the tunnel, the dimensionless ceiling temperatures in the fire channel are higher than in the case when the smoke curtain is not used. Moreover, there is no smoke in the evacuation channel. The fire size and train blockage do not have a considerable effect on the dimensionless temperatures and smoke volume rates in the shaft. Nonetheless, the dimensionless smoke temperatures in the shaft decrease with the increase in the shaft distance or the shaft size. Moreover, dimensionless smoke flow rates through the shaft increase with the decrease in the shaft distance or the increase in the shaft size. © 2013 International Association for Fire Safety Science.

Neutron scattering investigation of the d-d excitations below the Mott gap of CoO - Cowley, R.A.; Buyers, W.J.L.; Stock, C.; Yamani, Z.; Frost, C.; Taylor, J.W.; Prabhakaran, D. (Physical Review B - Condensed Matter and Materials Physics, 2013)
Neutron scattering is used to investigate the single-ion spin and orbital excitations below the Mott-Hubbard gap in CoO. Three excitations are reported at 0.870±0.009 eV, 1.84±0.03, and 2.30±0.15 eV. These were parametrized within a weak crystal field scheme with an intraorbital exchange of J(dd)=1.3±0.2 eV and a crystal field splitting 10Dq=0.94±0.10 eV. A reduced spin-orbit coupling of λ=-0.016±0.003 eV is derived from dilute samples of Mg0.97Co0.03O, measured to remove effects due to spin exchange and structural distortion parameters which break the cubic phase degeneracy of the orbital excitations complicating the inelastic spectrum. The peak at 1.84 eV, while reported using resonant x-ray and optical techniques, was absent or weak for nonresonant x-ray experiments and overlaps with the expected position of a 4A2 level. This transition is absent in the dipolar approximation but expected to have a finite quadrupolar matrix element that can be observed with neutron scattering techniques at larger momentum transfers. Our results agree with a crystal field analysis (in terms of Racah parameters and Tanabe-Sugano diagrams) and with previous calculations performed using local-density band theory for Mott insulating transition metal oxides. The results also demonstrate the use of neutron scattering for measuring dipole forbidden transitions in transition metal oxide systems. © 2013 American Physical Society.

Electrochemical performance of NaCo2O4 as electrode for supercapacitors - Tang, H.-W.; Gao, N.; Chang, Z.-R.; Li, B.; Yuan, X.-Z.; Wang, H.-J. (Chinese Chemical Letters, 2013)
Sub-micron-scaled sodium cobalt oxide (NaCo2O4) powders are prepared by a solid-state reaction method. Characterization using X-ray diffraction indicates that the synthesized NaCo2O4 has a hexagonal layered structure. The electrochemical performance of the NaCo2O4 electrodes is investigated using cyclic voltammetry and galvanostatic charge/discharge in NaOH solution. The results show that the specific capacitance of the NaCo2O4 electrode reaches 337 F/g over the potential range of 0.15-0.65 V at a mass normalized current of 50 mA/g. Moreover, NaCo2O4 exhibits very good stability and cycling performance as a supercapacitor material. © 2013 Zhao-Rong Chang.

The road to medical vibrational spectroscopy – a history - Mantsch, Henry H. (The Analyst, 2013)
The present Editorial chronicles the journey from classical infrared and Raman spectroscopy to medical vibrational spectroscopy, as experienced by a contemporary witness of the times. During the second half of the last century vibrational biospectroscopy became a topic of increasing global interest and has spawned a number of international conferences of which the most recent, SPEC 2012 – Shedding New Light on Disease, constitutes the basis of the present themed issue.
Keywords: animal; diagnostic imaging; editorial; equipment; history; human; infrared spectrophotometry; medicine; Raman spectrometry; vibration; Animals; Diagnostic Imaging; History, 20th Century; History, 21st Century; Humans; Medicine; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Vibration

Efficacy of genetically modified Bt toxins alone and in combinations against pink bollworm resistant to Cry1Ac and Cry2Ab - Tabashnik, B.E.; Fabrick, J.A.; Unnithan, G.C.; Yelich, A.J.; Masson, L.; Zhang, J.; Bravo, A.; Soberón, M. (PLoS ONE, 2013)
Evolution of resistance in pests threatens the long-term efficacy of insecticidal proteins from Bacillus thuringiensis (Bt) used in sprays and transgenic crops. Previous work showed that genetically modified Bt toxins Cry1AbMod and Cry1AcMod effectively countered resistance to native Bt toxins Cry1Ab and Cry1Ac in some pests, including pink bollworm ( Pectinophora gossypiella ). Here we report that Cry1AbMod and Cry1AcMod were also effective against a laboratory-selected strain of pink bollworm resistant to Cry2Ab as well as to Cry1Ab and Cry1Ac. Resistance ratios based on the concentration of toxin killing 50% of larvae for the resistant strain relative to a susceptible strain were 210 for Cry2Ab, 270 for Cry1Ab, and 310 for Cry1Ac, but only 1.6 for Cry1AbMod and 2.1 for Cry1AcMod. To evaluate the interactions among toxins, we tested combinations of Cry1AbMod, Cry1Ac, and Cry2Ab. For both the resistant and susceptible strains, the net results across all concentrations tested showed slight but significant synergism between Cry1AbMod and Cry2Ab, whereas the other combinations of toxins did not show consistent synergism or antagonism. The results suggest that the modified toxins might be useful for controlling populations of pink bollworm resistant to Cry1Ac, Cry2Ab, or both. © 2013 Tabashnik et al.

Immediate impacts on particulate and gaseous emissions from a T56 turbo-prop engine using a biofuel blend - Chan, T.W.; Pham, V.; Chalmers, J.; Davison, C.; Chishty, W.; Poitras, P. (SAE Technical Papers, 2013)
Adoption of hydro-processed esters and fatty acid biojet fuels is a critical component for the sustainability of the aviation industry. Aviation biofuels reduce pollution and provide alternatives to conventional fossil fuels. A study of the impacts of biofuels on emissions from a T56 turbo-prop engine was undertaken as a joint effort among several departments of the Government of Canada. In this study, particulate (including particle number and black carbon (BC) mass) and regulated gaseous emissions (CO2, CO, NO, NO 2, THC) were characterized with the engine operating on conventional F-34 jet fuel and jet fuel blended with camelina-based hydro-processed biojet fuel (C-HEFA) by 50% in volume. Emissions characterization, conducted after 20-hour ground engine durability tests, showed immediate significant reductions in particle number and BC mass when the engine was operated on the C-HEFA blend. Operating at high speed ground idle (HSGI) using the C-HEFA blend reduced particle number and BC mass emissions by 31% and 50%, respectively. At Take-off engine mode, particle number and BC mass reductions were 22% and 32%, respectively. In addition, particles generated from the C-HEFA blend were also observed to be slightly smaller than those generated from the conventional jet fuel by 2-4 nanometer (nm). CO emissions from the C-HEFA blend were lower by 4-6%. CO2 emissions from the C-HEFA blend were lower by approximately 1%, consistent with the difference in hydrocarbon ratios in the C-HEFA blend.
Keywords: Aviation industry; Biofuel blends; Black carbon; Critical component; Engine durability; Mass emissions; Mass reduction; Particle numbers; Carbon dioxide; Durability; Engines; Exhibitions; Jet fuel; Reduction; Biofuels

Quantum confinement in Si and Ge nanostructures: Effect of crystallinity - Barbagiovanni, Eric G.; Lockwood, David J.; Costa Filho, Raimundo N.; Goncharova, Lyudmila V.; Simpson, Peter J. (SPIE - International Society for Optical Engineering. Proceedings, 2013)
We look at the relationship between the preparation method of Si and Ge nanostructures (NSs) and the structural, electronic, and optical properties in terms of quantum confinement (QC). QC in NSs causes a blue shift of the gap energy with decreasing NS dimension. Directly measuring the effect of QC is complicated by additional parameters, such as stress, interface and defect states. In addition, differences in NS preparation lead to differences in the relevant parameter set. A relatively simple model of QC, using a 'particle-in-a-box'-type perturbation to the effective mass theory, was applied to Si and Ge quantum wells, wires and dots across a variety of preparation methods. The choice of the model was made in order to distinguish contributions that are solely due to the effects of QC, where the only varied experimental parameter was the crystallinity. It was found that the hole becomes de-localized in the case of amorphous materials, which leads to stronger confinement effects. The origin of this result was partly attributed to differences in the effective mass between the amorphous and crystalline NS as well as between the electron and hole. Corrections to our QC model take into account a position dependent effective mass. This term includes an inverse length scale dependent on the displacement from the origin. Thus, when the deBroglie wavelength or the Bohr radius of the carriers is on the order of the dimension of the NS the carriers 'feel' the confinement potential altering their effective mass. Furthermore, it was found that certain interface states (Si-O-Si) act to pin the hole state, thus reducing the oscillator strength. © 2013 SPIE.
Keywords: Confinement effects; Confinement potential; Crystallinities; Effective mass; Effective-mass theory; Experimental parameters; Oscillator strengths; Position-dependent effective mass; Amorphous materials; Germanium; Interface states; Nanostructures; Photonics; Quantum confinement; Semiconducting germanium; Silicon

Microindentation creep of monophasic calcium-silicate-hydrates - Nguyen, D.-T.; Alizadeh, R.; Beaudoin, J.J.; Pourbeik, P.; Raki, L. (Cement and Concrete Composites, 2013)
Microindentation creep results for monophasic synthetic C-S-H (C/S = 0.6-1.5), 1.4 nm tobermorite, jennite and calcium hydroxide at 11%RH are reported. Creep results for well hydrated cement paste and C3S 'composite' systems are also described. The significance of the co-linear behavior of creep modulus functions of indentation modulus and indentation hardness for C-S-H obtained by microindentation and nanoindentation methods is discussed. The porosity dependence of creep modulus and the general equivalence of density values determined by helium pycnometry and by calculations employing unit cell dimensions (obtained using X-ray crystallography techniques) are also discussed in terms of postulates for the existence of two types of C-S-H. Comment on the compatibility of the creep modulus data for 1.4 nm tobermorite and jennite with models of C-S-H present in cement paste is provided. © 2013 Elsevier Ltd. All rights reserved.

Review of the punching shear behavior of concrete flat slabs in ambient and elevated temperature - Ghoreishi, Mehrafarid; Bagchi, Ashutosh; Sultan, Mohamed A. (Journal of Structural Fire Engineering, 2013)
There are a number of benefits associated with two-way concrete flat slab construction for office buildings, parking garages and apartments - for example, reduced formwork, prompt erection, flexibility of partitions, and minimal increase in story heights. However, concrete flat slabs could be quite vulnerable to punching shear failure in the event of a fire. The objective of the present article is to provide a state of the art review of the existing research and the issues associated with concrete flat slabs in fire and elevated temperature. There are a number of experimental and analytical studies on the punching shear behavior of concrete flat slabs in ambient conditions, available in the literature. Based on these studies, it is found that punching shear capacity in ambient condition is affected by many factors, which may not remain constant during a fire exposure. Only a limited number of studies on concrete flat slabs for punching shear failure in fire are available. This paper reviews the available experimental and analytical studies, standards and codes to address the research gap in estimating of punching shear strength of concrete flat slab-column connections without shear reinforcement.
Keywords: Elevated temperature; Fire safety; Flat slabs; Punching shear; Punching shear capacity; Punching shear strength; Slab-column connection; State-of-the art reviews; Columns (structural); Fires; Office buildings; Reinforced concrete; Concretes

Experimental and theoretical study for tunnel fires with natural ventilation - Yuan, Zhongyuan; Lei, Bo; Kashef, Ahmed (Fire Technology, 2013)
Natural ventilation mode is a ventilation strategy to control fire-induced hot smoke and provide safe and secure egress routes in subway tunnels. The study was carried out in a 1/15 reduced-scale tunnel using Froude modeling technique to investigate the fire-induced smoke temperature distribution and smoke exhaust through vertical shafts located at the ceiling of the scaled tunnel. A porous bed burner placed on the tunnel floor was used to simulate the fire source and propane was used as the fuel. The temperature distributions under the tunnel ceiling were measured using a series of K-type thermocouples to analyze smoke temperature distribution characteristics. The smoke temperature and velocity in the ventilation shafts were also monitored using hot wire anemometers. The effect of fire size, shaft distance, shaft geometry, train blockage on ceiling temperature distributions and smoke exhaust from shafts were studied. Based on the one-dimensional theory, the ceiling temperature decay characteristics were studied. Finally, empirical equations for predicting ceiling temperature distributions and smoke exhaust in tunnel fires with a natural ventilation mode were derived.
Keywords: reduced-scaled experiment; natural ventilation; smoke temperature; smoke exhaust

Microindentation creep of 45 year old hydrated Portland cement paste - Pourbeik, P.; Alizadeh, R.; Beaudoin, J.J.; Nguyen, D.-T.; Raki, L. (Advances in Cement Research, 2013)
Microindentation methods were used to study the creep behaviour of cement paste hydrated for 45 years. These old pastes were prepared having a wide range of water/cement ratios varying from 0.5 to 1.0. The porosity dependence of the indentation parameters (creep modulus, indentation modulus and indentation hardness) was determined and is discussed in the context of possible creep mechanisms. Microindentation creep was also determined for 3 year old cement paste and young paste hydrated for 3 and 7 days. Variation in creep behaviour of the cement pastes for the three age groups is discussed in terms of nanostructural differences.

Analysis of localized surface plasmon resonance in glass-supported gold nanoparticles with a hexagonal pattern - Hajebifard, A.; Yuan, J.; Zou, S.; Berini, P. (SPIE - International Society for Optical Engineering. Proceedings, 2013)
An approach has been devised to create a hexagonal pattern of glass-supported gold nanoparticles (AuNPs) with controllable particle size and inter-particle spacing, by combining the self-assembly of block copolymer micelle-loaded metal precursors with a seeding growth method. Absorbance spectra as an optical response of the AuNP arrays were measured to obtain their LSPR peak position (λLSPR). There was a red shift in λLSPR with increasing cover medium refractive index for all fabricated and simulated arrays. A comparison between computed and measured λLSPR for a 33 nm AuNP array suggests that large nanoparticles produced by this fabrication method have ellipsoidal shapes rather than spherical ones, as in the case of small AuNP arrays. © 2013 SPIE.
Keywords: Absorbance spectrum; COMSOL; Embedding ratios; Gold nanoparticle; Localized surface plasmon resonance; Seeding growth; Block copolymers; Glass; Gold; Metal nanoparticles; Photonics; Plasmons; Refractive index; Self assembly; Surface plasmon resonance

Ultrafast relaxation dynamics of uracil probed via strong field dissociative ionization - Matsika, S.; Spanner, M.; Kotur, M.; Weinacht, T.C. (The Journal of Physical Chemistry A, 2013)
We study the ultrafast relaxation dynamics of uracil excited to the first bright ππ* state (S2) by an ultrafast laser pulse in the deep ultraviolet (central wavelength λ0 = 260 nm). With a unique combination of strong field dissociative ionization measurements, state of the art strong field ionization calculations, and high level ab initio calculations of excited neutral and ionic states at critical points along the neutral potentials, we are able to gain a detailed picture of the relaxation dynamics of the molecule, which resolves earlier disagreements regarding measurements and calculations of the relaxation. © 2013 American Chemical Society.
Keywords: Central wavelength; Deep ultraviolet; Dissociative ionization; High-level ab initio calculations; Relaxation dynamics; State of the art; Strong field ionization; Ultrafast relaxation dynamics; Aromatic compounds; Dissociation; Ionization

Fundamental and torsional combination bands of two isomers of the OCS-CO2 complex in the CO2 ν3 region - Norooz Oliaee, J.; Dehghany, M.; Moazzen-Ahmadi, N.; McKellar, A.R.W. (The Journal of Physical Chemistry A, 2013)
Spectra of two isomers of the weakly bound complex OCS-CO2 are observed in the region of the CO2 ν3 fundamental vibration (∼2349 cm-1), using an infrared tunable diode laser to probe a pulsed supersonic slit-jet expansion. Two bands are measured and analyzed for each isomer, the fundamental asymmetric stretch of the CO 2 component and a combination band involving this fundamental plus the intermolecular out-of-plane torsional mode. For one isomer, the corresponding torsional combination band is also detected in the OCS ν1 stretching region (∼2060 cm-1). The resulting torsional frequencies are found to be 18.8 and 15.9 cm-1 for isomers a and b of OCS-CO2, respectively. This may be the first time that such a combination band is observed for a higher-energy isomer of a weakly bound complex. © 2013 American Chemical Society.
Keywords: Combination bands; Fundamental vibrations; Out-of-plane; Stretching region; Torsional frequency; Torsional modes; Tunable diode lasers; Weakly bound complexes; Freons; Isomers; Supersonic aerodynamics; Carbon dioxide

Stark effect in the benzene dimer - Schnell, M.; Bunker, P.R.; Von Helden, G.; Grabow, J.-U.; Meijer, G.; Van Der Avoird, A. (The Journal of Physical Chemistry A, 2013)
Ab initio calculations of the six-dimensional intermolecular potential have shown the benzene dimer to be an asymmetric top molecule at equilibrium with one benzene moiety forming the "stem" and the other a "tilted cap" in a T-shaped structure. Internal rotation of the cap about its C 6 axis is essentially free; the barriers for cap tilting and for internal rotation of the stem about its C6 axis are hindered by successively higher barriers. In previous work we have validated these theoretical results using Fourier transform microwave spectroscopy in conjunction with dynamics calculations. We have also measured the Stark effect, and despite the fact that the equilibrium structure is that of an asymmetric top, the assigned transitions involving K = 0 exhibit a second-order Stark effect whereas those involving K = 1 exhibit a first-order Stark effect. This is typical for a symmetric-top molecule, but anomalous for an asymmetric-top molecule. We use symmetry arguments to explain how this asymmetric-top molecule can have a first-order Stark effect in certain states that have excitation of cap internal rotation. Cap internal rotation is essentially the twisting of the monomers relative to each other about the intermolecular axis, and such torsional motion occurs in other asymmetric top dimers such as benzene-CO and benzene-H2O. These latter dimers will also have levels that exhibit a first-order Stark effect, which we can explain using our symmetry arguments. © 2013 American Chemical Society.
Keywords: Ab initio calculations; Asymmetric top; Dynamics calculations; Equilibrium structures; Fourier transform microwave spectroscopy; Intermolecular potentials; Internal rotations; Torsional motion; Benzene; Dimers; Microwave spectroscopy; Molecules; Stark effect

A new look at the infrared spectrum of the weakly bound CO-N2 complex - Rezaei, M.; Michaelian, K.H.; Moazzen-Ahmadi, N.; McKellar, A.R.W. (The Journal of Physical Chemistry A, 2013)
A broad-band (2135-2165 cm-1) infrared spectrum of the CO-N 2 van der Waals complex is obtained, using a tunable quantum cascade laser to probe a pulsed supersonic expansion from a slit jet source. Analysis of the spectrum results in the characterization of four new 'stacks' of rotational levels for CO-orthoN2 (all in the vCO = 1 upper state) and five new stacks for CO-paraN2 (three in the upper state and two in the vCO = 0 lower state). This considerably expands our knowledge of a rather fundamental weakly bound complex and should lead to improved determinations of the intermolecular forces governing interactions between the carbon monoxide and nitrogen molecules. © 2013 American Chemical Society.
Keywords: Broad bands; Infrared spectrum; Inter-molecular forces; Nitrogen molecule; Pulsed supersonic expansions; Rotational levels; Van der Waals complex; Weakly bound complexes; Carbon monoxide; Chemical bonds; Molecules; Quantum cascade lasers; Supersonic aerodynamics; Van der Waals forces; Spectroscopy

Efficient basis sets for non-covalent interactions in XDM-corrected density-functional theory - Johnson, E.R.; Otero-De-La-Roza, A.; Dale, S.G.; Dilabio, G.A. (Journal of Chemical Physics, 2013)
In the development and application of dispersion-corrected density-functional theory, the effects of basis set incompleteness have been largely mitigated through the use of very large, nearly-complete basis sets. However, the use of such large basis sets makes application of these methods inefficient for large systems. In this work, we examine a series of basis sets, including Pople-style, correlation-consistent, and polarization-consistent bases, for their ability to efficiently and accurately predict non-covalent interactions when used in conjunction with the exchange-hole dipole moment (XDM) dispersion model. We find that the polarization-consistent 2 (pc-2) basis sets, and two modifications thereof with some diffuse functions removed, give performance of comparable quality to that obtained with aug-cc-pVTZ basis sets, while being roughly 12 to 23 times faster computationally. The behavior is explained, in part, by the role of diffuse functions in recovering small density changes in the intermolecular region. The general performance of the modified basis sets is tested by application of XDM to standard intermolecular benchmark sets at, and away from, equilibrium. © 2013 AIP Publishing LLC.
Keywords: Basis sets; Density change; Development and applications; Diffuse functions; Dispersion modeling; Large system; Non-covalent interaction; Density functional theory; Dispersions; Polarization; Benchmarking

Diabetes-associated periodontitis molecular features in infrared spectra of gingival crevicular fluid - Xiang, X.; Duarte, P.M.; Lima, J.A.; Santos, V.R.; Goncxalves, T.D.; Miranda, T.S.; Liu, K.-Z. (Journal of Periodontology, 2013)
Background: It has been established previously that infrared spectroscopy (IRS) can be used to identify periodontitis-specific molecular signatures in gingival crevicular fluid (GCF) and to confirm clinical diagnoses. This follow-up study is designed to assess whether this novel technique is also able to differentiate diseased from healthy sites in patients with diabetes mellitus (DM) by analyzing the molecular fingerprints embedded in the GCF. Methods: A total of 65 patients with DM with moderate-to-severe chronic periodontitis (CP) was recruited, and 15 individuals without DM (65 sites) without periodontal diseases were used as control. Clinical examination and GCF samples were taken from a total of 351 sites, including periodontitis (109), gingivitis (115), and healthy (127) sites. Corresponding absorption spectra of GCF samples were acquired and processed, and the relative contributions of key functional groups in the infrared spectra were identified and analyzed. The qualitative assessment of clinical relevance of these GCF spectra was interpreted with multivariate statistical analysis: linear discriminant analysis (LDA). Results: Spectral analysis revealed several molecular signatures representing vibrations in protein (amide I and II), lipid ester, and sugar moieties in the GCF of patients with DM with CP and non-DM controls. The diagnostic accuracy for distinction between healthy and CP sites in patients with DM determined by LDA of GCF spectra was 95.3% for the training set of samples and 87.5% for the validation set. Additional LDA of GCF spectra from healthy sites of non-DM controls and patients with DM revealed 100% diagnostic accuracy for the training set and 86.7% for the validation set. The regions robotically selected by LDA for the two analyses were slightly different in that first LDA identified major regions clustered with the side chain vibrations originating from protein and DNA contents, whereas the second was predominantly the glycation and protein components. Conclusion: IRS is a feasible method to differentiate disease-specific molecular signatures in GCF in the presence of DM and to generate a complex biochemical profile of GCF to identify DM-specific spectral features.

Quantum random bit generation using energy fluctuations in stimulated Raman scattering - Bustard, P.J.; England, D.G.; Nunn, J.; Moffatt, D.; Spanner, M.; Lausten, R.; Sussman, B.J. (Optics Express, 2013)
Random number sequences are a critical resource in modern information processing systems, with applications in cryptography, numerical simulation, and data sampling. We introduce a quantum random number generator based on the measurement of pulse energy quantum fluctuations in Stokes light generated by spontaneously-initiated stimulated Raman scattering. Bright Stokes pulse energy fluctuations up to five times the mean energy are measured with fast photodiodes and converted to unbiased random binary strings. Since the pulse energy is a continuous variable, multiple bits can be extracted from a single measurement. Our approach can be generalized to a wide range of Raman active materials; here we demonstrate a prototype using the optical phonon line in bulk diamond.
Keywords: Continuous variables; Critical resources; Information processing systems; Quantum fluctuation; Quantum random number generators; Raman-active materials; Random bit generations; Stokes pulse energy fluctuations; Data processing; Quantum electronics; Random number generation; Stimulated Raman scattering

A simplified model for thermal-wave cavity self-consistent measurement of thermal diffusivity - Shen, J.; Zhou, J.; Gu, C.; Neill, S.; Michaelian, K.H.; Fairbridge, C.; Astrath, N.G.C.; Baesso, M.L. (Review of Scientific Instruments, 2013)
A simplified theoretical model was developed for the thermal-wave cavity (TWC) technique in this study. This model takes thermal radiation into account and can be employed for absolute measurements of the thermal diffusivity of gas and liquid samples without any knowledge of geometrical and thermal parameters of the components of the TWC. Using this model and cavity-length scans, thermal diffusivities of air and distilled water were accurately and precisely measured as (2.191 ± 0.004) × 10-5 and (1.427 ± 0.009) × 10-7 m2 s-1, respectively, in very good agreement with accepted literature values. © 2013 Crown.
Keywords: Absolute measurements; Distilled water; Liquid sample; Theoretical modeling; Thermal parameters; Thermal-wave cavity; Equipment; Instruments; Thermal diffusivity

Reply - Kumar, K.; Jassal, D.S. (Echocardiography, 2013)
Keywords: anesthetic agent; hypertensive agent; inotropic agent; cardiopulmonary bypass; heart left ventricle filling pressure; heart muscle revascularization; heart surgery; human; letter; lung capillary pressure; morbidity; off pump surgery; perioperative period; postoperative period; priority journal; prognosis; pulmonary artery catheter; tissue Doppler imaging; transthoracic echocardiography; Blood Pressure Determination; Cardiac Surgical Procedures; Elasticity Imaging Techniques; Female; Humans; Male; Monitoring, Intraoperative; Stroke Volume; Ventricular Dysfunction, Left

A novel dominant glossy mutation causes suppression of wax biosynthesis pathway and deficiency of cuticular wax in Brassica napus - Pu, Y.; Gao, J.; Guo, Y.; Liu, T.; Zhu, L.; Xu, P.; Yi, B.; Wen, J.; Tu, J.; Ma, C.; Fu, T.; Zou, J.; et al. (BMC Plant Biology, 2013)
Background: The aerial parts of land plants are covered with cuticular waxes that limit non-stomatal water loss and gaseous exchange, and protect plants from ultraviolet radiation and pathogen attack. This is the first report on the characterization and genetic mapping of a novel dominant glossy mutant (BnaA.GL) in Brassica napus.Results: Transmission electron microscopy revealed that the cuticle ultrastructure of GL mutant leaf and stem were altered dramatically compared with that of wide type (WT). Scanning electron microscopy corroborated the reduction of wax on the leaf and stem surface. A cuticular wax analysis of the GL mutant leaves further confirmed the drastic decrease in the total wax content, and a wax compositional analysis revealed an increase in aldehydes but a severe decrease in alkanes, ketones and secondary alcohols. These results suggested a likely blockage of the decarbonylation step in the wax biosynthesis pathway. Genetic mapping narrowed the location of the BnaA.GL gene to the end of A9 chromosome. A single-nucleotide polymorphism (SNP) chip assay in combination with bulk segregant analysis (BSA) also located SNPs in the same region. Two SNPs, two single sequence repeat (SSR) markers and one IP marker were located on the flanking region of the BnaA.GL gene at a distance of 0.6 cM. A gene homologous to ECERIFERUM1 (CER1) was located in the mapped region. A cDNA microarray chip assay revealed coordinated down regulation of genes encoding enzymes of the cuticular wax biosynthetic pathway in the glossy mutant, with BnCER1 being one of the most severely suppressed genes.Conclusions: Our results indicated that surface wax biosynthesis is broadly affected in the glossy mutant due to the suppression of the BnCER1 and other wax-related genes. These findings offer novel clues for elucidating the molecular basis of the glossy phenotype. © 2013 Pu et al.; licensee BioMed Central Ltd.
Keywords: Brassica; Brassica napus; Embryophyta

Identifying purpose behind electoral tweets - Mohammad, S.M.; Kiritchenko, S.; Martin, J. (Proceedings of the 2nd International Workshop on Issues of Sentiment Discovery and Opinion Mining, WISDOM 2013 - Held in Conjunction with SIGKDD 2013, 2013)
Tweets pertaining to a single event, such as a national election, can number in the hundreds of millions. Automatically analyzing them is beneficial in many downstream natural language applications such as question answering and summarization. In this paper, we propose a new task: identifying purpose behind electoral tweets|why do people post election-oriented tweets? We show that identifying purpose is related to sentiment and emotion detection, but yet significantly different. Detecting purpose has a number of applications including detecting the mood of the electorate, estimating the popularity of policies, identifying key issues of contention, and predicting the course of events. We create a large dataset of electoral tweets and annotate a few thousand tweets for purpose. We develop a system that automatically classifies electoral tweets as per their purpose, obtaining an accuracy of 44.58% on an 11-class task and an accuracy of 73.91% on a 3-class task (both accuracies well above the most-frequent-class baseline). We also show that resources developed for emotion detection are helpful for detecting purpose.
Keywords: Emotion detection; Key Issues; Large dataset; National elections; Natural language applications; Question Answering; Single event; Data mining; Natural language processing systems

Genomic DNA enrichment using sequence capture microarrays: a novel approach to discover sequence nucleotide polymorphisms (SNP) in Brassica napus L - Clarke, W.E.; Parkin, I.A.; Gajardo, H.A.; Gerhardt, D.J.; Higgins, E.; Sidebottom, C.; Sharpe, A.G.; Snowdon, R.J.; Federico, M.L.; Iniguez-Luy, F.L. (PLoS ONE, 2013)
Targeted genomic selection methodologies, or sequence capture, allow for DNA enrichment and large-scale resequencing and characterization of natural genetic variation in species with complex genomes, such as rapeseed canola ( Brassica napus L., AACC, 2n=38). The main goal of this project was to combine sequence capture with next generation sequencing (NGS) to discover single nucleotide polymorphisms (SNPs) in specific areas of the B. napus genome historically associated (via quantitative trait loci -QTL- analysis) to traits of agronomical and nutritional importance. A 2.1 million feature sequence capture platform was designed to interrogate DNA sequence variation across 47 specific genomic regions, representing 51.2 Mb of the Brassica A and C genomes, in ten diverse rapeseed genotypes. All ten genotypes were sequenced using the 454 Life Sciences chemistry and to assess the effect of increased sequence depth, two genotypes were also sequenced using Illumina HiSeq chemistry. As a result, 589,367 potentially useful SNPs were identified. Analysis of sequence coverage indicated a four-fold increased representation of target regions, with 57% of the filtered SNPs falling within these regions. Sixty percent of discovered SNPs corresponded to transitions while 40% were transversions. Interestingly, fifty eight percent of the SNPs were found in genic regions while 42% were found in intergenic regions. Further, a high percentage of genic SNPs was found in exons (65% and 64% for the A and C genomes, respectively). Two different genotyping assays were used to validate the discovered SNPs. Validation rates ranged from 61.5% to 84% of tested SNPs, underpinning the effectiveness of this SNP discovery approach. Most importantly, the discovered SNPs were associated with agronomically important regions of the B. napus genome generating a novel data resource for research and breeding this crop species. © 2013 Clarke et al.
The authors affiliated with NRC were with the NRC Institute for Plant Biotechnology prior to April 1, 2012.

Wide-field UV imaging: Current capabilities and performance requirements for future missions - Côté, P. (Advances in Space Research, 2013)
I give a brief history of UV space telescopes, paying particularly attention to imaging facilities that operate at UV wavelengths. I examine a number of science drivers for space imaging at UV and blue-optical wavelengths (≲ 0.5 μm) for the coming decade, and discuss some possible synergies with future optical-IR imaging facilities, such as LSST and Euclid. While the present "Golden Age" of UV astronomy may be drawing to a close, an important new imaging facility - the Ultraviolet Imaging Telescope (UVIT) onboard Astrosat - should begin operations in 2014. This instrument will provide astronomers with a wide-field (Ω ∼ 0.2 deg2) UV imaging capability at an angular resolution (FWHM ∼1.5″-1.8″) that approaches those of ground-based optical telescopes. I also describe a proposed wide-field UV/blue-optical imaging telescope (CASTOR) that would provide HST-quality images over a ∼0.7 deg2 field in three broad filters covering the range 150-550 nm. Crown Copyright © 2013.

Magnon breakdown in a two dimensional triangular lattice heisenberg antiferromagnet of multiferroic LuMnO3 - Oh, J.; Le, M.D.; Jeong, J.; Lee, J.-H.; Woo, H.; Song, W.-Y.; Perring, T.G.; Buyers, W.J.L.; Cheong, S.-W.; Park, J.-G. (Physical Review Letters, 2013)
The breakdown of magnons, the quasiparticles of magnetic systems, has rarely been seen. By using an inelastic neutron scattering technique, we report the observation of spontaneous magnon decay in multiferroic LuMnO3, a simple two dimensional Heisenberg triangular lattice antiferromagnet, with large spin S=2. The origin of this rare phenomenon lies in the nonvanishing cubic interaction between magnons in the spin Hamiltonian arising from the noncollinear 120 spin structure. We observed all three key features of the nonlinear effects as theoretically predicted: a rotonlike minimum, a flat mode, and a linewidth broadening, in our inelastic neutron scattering measurements of single crystal LuMnO3. Our results show that quasiparticles in a system hitherto thought of as "classical" can indeed break down. © 2013 American Physical Society.
Keywords: Heisenberg antiferromagnets; Inelastic neutrons; Linewidth broadening; Magnetic system; Nonlinear effect; Spin hamiltonian; Triangular lattice; Triangular lattice antiferromagnet; Inelastic neutron scattering; Two dimensional

The large-scale structure of the halo of the Andromeda galaxy. I. Global stellar density, morphology and metallicity properties - Ibata, Rodrigo A.; Lewis, Geraint F.; McConnachie, Alan W.; Martin, Nicolas F.; Irwin, Michael J.; Ferguson, Annette M. N.; Babul, Arif; Bernard, Edouard J.; Chapman, Scott C.; Collins, Michelle; Fardal, Mark; MacKey, A. D.; et al. (The Astrophysical Journal, 2013)
We present an analysis of the large-scale structure of the halo of the Andromeda galaxy, based on the Pan-Andromeda Archeological Survey (PAndAS), currently the most complete map of resolved stellar populations in any galactic halo. Despite the presence of copious substructures, the global halo populations follow closely power-law profiles that become steeper with increasing metallicity. We divide the sample into stream-like populations and a smooth halo component (defined as the population that cannot be resolved into spatially distinct substructures with PAndAS). Fitting a three-dimensional halo model reveals that the most metal-poor populations () are distributed approximately spherically (slightly prolate with ellipticity c/a = 1.09 ± 0.03), with only a relatively small fraction residing in discernible stream-like structures (f stream = 42%). The sphericity of the ancient smooth component strongly hints that the dark matter halo is also approximately spherical. More metal-rich populations contain higher fractions of stars in streams, with f stream becoming as high as 86% for . The space density of the smooth metal-poor component has a global power-law slope of γ = -3.08 ± 0.07, and a non-parametric fit shows that the slope remains nearly constant from 30 kpc to 300 kpc. The total stellar mass in the halo at distances beyond 2° is 1.1 × 1010 M, while that of the smooth component is 3 × 109 M. Extrapolating into the inner galaxy, the total stellar mass of the smooth halo is plausibly 8 × 109 M. We detect a substantial metallicity gradient, which declines from 〈[Fe/H]〉 = -0.7 at R = 30 kpc to 〈[Fe/H]〉 = -1.5 at R = 150 kpc for the full sample, with the smooth halo being 0.2 dex more metal poor than the full sample at each radius. While qualitatively in line with expectations from cosmological simulations, these observations are of great importance as they provide a prototype template that such simulations must now be able to reproduce in quantitative detail.

Supermassive black holes and their host galaxies. II. the correlation with near-infrared luminosity revisited - Läsker, Ronald; Ferrarese, Laura; van de Ven, Glenn; Shankar, Francesco (The Astrophysical Journal, 2013)
We present an investigation of the scaling relations between supermassive black hole (SMBH) masses, M •, and their host galaxies' K-band bulge (L bul) and total (L tot) luminosities. The wide-field WIRCam imager at the Canada-France-Hawaii-Telescope was used to obtain the deepest and highest resolution near-infrared images available for a sample of 35 galaxies with securely measured M •, selected irrespective of Hubble type. For each galaxy, we derive bulge and total magnitudes using a two-dimensional image decomposition code that allows us to account, if necessary, for large- and small-scale disks, cores, bars, nuclei, rings, envelopes, and spiral arms. We find that the present-day M •-L bul and M •-L tot relations have consistent intrinsic scatter, suggesting that M • correlates equally well with bulge and total luminosity of the host. Our analysis provides only mild evidence of a decreased scatter if the fit is restricted to elliptical galaxies. The log-slopes of the M •-L bul and M •-L tot relations are 0.75 ± 0.10 and 0.92 ± 0.14, respectively. However, while the slope of the M •-L bul relation depends on the detail of the image decomposition, the characterization of M •-L tot does not. Given the difficulties and ambiguities of decomposing galaxy images into separate components, our results indicate that L tot is more suitable as a tracer of SMBH mass than L bul, and that the M •-L tot relation should be used when studying the co-evolution of SMBHs and galaxies.

Supermassive black holes and their host galaxies. I. Bulge luminosities from dedicated near-infrared data - Läsker, Ronald; Ferrarese, Laura; van de Ven, Glenn (The Astrophysical Journal, 2013)
In an effort to secure, refine, and supplement the relation between central supermassive black hole masses, M •, and the bulge luminosities of their host galaxies, L bul, we obtained deep, high spatial resolution K-band images of 35 nearby galaxies with securely measured M •, using the wide-field WIRCam imager at the Canada-France-Hawaii-Telescope. A dedicated data reduction and sky subtraction strategy was adopted to estimate the brightness and structure of the sky, a critical step when tracing the light distribution of extended objects in the near-infrared. From the final image product, bulge and total magnitudes were extracted via two-dimensional profile fitting. As a first order approximation, all galaxies were modeled using a simple Sérsic-bulge+exponential-disk decomposition. However, we found that such models did not adequately describe the structure that we observed in a large fraction of our sample galaxies which often include cores, bars, nuclei, inner disks, spiral arms, rings, and envelopes. In such cases, we adopted profile modifications and/or more complex models with additional components. The derived bulge magnitudes are very sensitive to the details and number of components used in the models, although total magnitudes remain almost unaffected. Usually, but not always, the luminosities and sizes of the bulges are overestimated when a simple bulge+disk decomposition is adopted in lieu of a more complex model. Furthermore, we found that some spheroids are not well fit when the ellipticity of the Sérsic model is held fixed. This paper presents the details of the image processing and analysis, while we discuss how model-induced biases and systematics in bulge magnitudes impact the M •-L bul relation in a companion paper.

Nanomechanical AC susceptometry of an individual mesoscopic ferrimagnet - Losby, J. E.; Diao, Z.; Fani Sani, F.; Grandmont, D. T.; Belov, M.; Burgess, J. A.; Hiebert, W. K.; Freeman, M. R. (Solid State Communications, 2013)
A novel method for simultaneous detection of both DC and time-dependent magnetic signatures in individual mesoscopic structures has emerged from early studies in spin mechanics. Multifrequency nanomechanical detection of AC susceptibility and its harmonics highlights reversible nonlinearities in the magnetization response of a single yttrium iron garnet (YIG) element, separating them from hysteretic jumps in the DC magnetization.

Determination of localized visibility in off-axis electron holography - McLeod, Robert A.; Kupsta, Martin; Malac, Marek (Ultramicroscopy, 2013)
Off-axis electron holography is a wavefront-split interference method for the transmission electron microscope that allows the phase shift and amplitude of the electron wavefront to be separated and quantitatively measured. An additional, third component of the holographic signal is the coherence of the electron wavefront. Historically, wavefront coherence has been evaluated by measurement of the holographic fringe visibility (or contrast) based on the minimum and maximum intensity values. We present a method based on statistical moments is presented that allows allow the visibility to be measured in a deterministic and reproducible fashion suitable for quantitative analysis. We also present an algorithm, based on the Fourier-ratio method, which allows the visibility to be resolved in two-dimensions, which we term the local visibility. The local visibility may be used to evaluate the loss of coherence due to electron scattering within a specimen, or as an aid in image analysis and segmentation. The relationship between amplitude and visibility may be used to evaluate the composition and mass thickness of a specimen by means of a 2-D histogram. Results for a selection of elements (C, Al, Si, Ti, Cr, Cu, Ge, and Au) are provided. All presented visibility metrics are biased at low-dose conditions by the presence of shot-noise, for which we provide methods for empirical normalization to achieve linear response.
Keywords: 2-D histograms; Coherence loss; Electron coherence; Fringe contrasts; Interference methods; Maximum intensities; Off-axis electron holography; Wavefront coherence; Electron holography; Electrons; Germanium; Gold; Graphic methods; Incoherent scattering; Titanium; Transmission electron microscopy; Underwater acoustics; Wavefronts; Visibility

SMPDB 2.0: big improvements to the small molecule pathway database - Jewison, Timothy; Su, Yilu; Disfany, Fatemeh Miri; Liang, Yongjie; Knox, Craig; MacIejewski, Adam; Poelzer, Jenna; Huynh, Jessica; Zhou, You; Arndt, David; Djoumbou, Yannick; Liu, Yifeng; et al. (Nucleic Acids Research, 2013)
The Small Molecule Pathway Database (SMPDB, http://www.smpdb.ca) is a comprehensive, colorful, fully searchable and highly interactive database for visualizing human metabolic, drug action, drug metabolism, physiological activity and metabolic disease pathways. SMPDB contains >600 pathways with nearly 75% of its pathways not found in any other database. All SMPDB pathway diagrams are extensively hyperlinked and include detailed information on the relevant tissues, organs, organelles, subcellular compartments, protein cofactors, protein locations, metabolite locations, chemical structures and protein quaternary structures. Since its last release in 2010, SMPDB has undergone substantial upgrades and significant expansion. In particular, the total number of pathways in SMPDB has grown by >70%. Additionally, every previously entered pathway has been completely redrawn, standardized, corrected, updated and enhanced with additional molecular or cellular information. Many SMPDB pathways now include transporter proteins as well as much more physiological, tissue, target organ and reaction compartment data. Thanks to the development of a standardized pathway drawing tool (called PathWhiz) all SMPDB pathways are now much more easily drawn and far more rapidly updated. PathWhiz has also allowed all SMPDB pathways to be saved in a BioPAX format. Significant improvements to SMPDB's visualization interface now make the browsing, selection, recoloring and zooming of pathways far easier and far more intuitive. Because of its utility and breadth of coverage, SMPDB is now integrated into several other databases including HMDB and DrugBank. © 2013 The Author(s). Published by Oxford University Press.

DrugBank 4.0: shedding new light on drug metabolism - Law, Vivian; Knox, Craig; Djoumbou, Yannick; Jewison, Tim; Guo, An Chi; Liu, Yifeng; Maciejewski, Adam; Arndt, David; Wilson, Michael; Neveu, Vanessa; Tang, Alexandra; Gabriel, Geraldine; et al. (Nucleic Acids Research, 2013)
DrugBank (http://www.drugbank.ca) is a comprehensive online database containing extensive biochemical and pharmacological information about drugs, their mechanisms and their targets. Since it was first described in 2006, DrugBank has rapidly evolved, both in response to user requests and in response to changing trends in drug research and development. Previous versions of DrugBank have been widely used to facilitate drug and in silico drug target discovery. The latest update, DrugBank 4.0, has been further expanded to contain data on drug metabolism, absorption, distribution, metabolism, excretion and toxicity (ADMET) and other kinds of quantitative structure activity relationships (QSAR) information. These enhancements are intended to facilitate research in xenobiotic metabolism (both prediction and characterization), pharmacokinetics, pharmacodynamics and drug design/discovery. For this release, >1200 drug metabolites (including their structures, names, activity, abundance and other detailed data) have been added along with >1300 drug metabolism reactions (including metabolizing enzymes and reaction types) and dozens of drug metabolism pathways. Another 30 predicted or measured ADMET parameters have been added to each DrugCard, bringing the average number of quantitative ADMET values for Food and Drug Administration-approved drugs close to 40. Referential nuclear magnetic resonance and MS spectra have been added for almost 400 drugs as well as spectral and mass matching tools to facilitate compound identification. This expanded collection of drug information is complemented by a number of new or improved search tools, including one that provides a simple analyses of drug-target, -enzyme and -transporter associations to provide insight on drug-drug interactions. © 2013 The Author(s). Published by Oxford University Press.

Major substructure in the M31 outer halo: the south-west cloud - Bate, N. F.; Conn, A. R.; McMonigal, B.; Lewis, G. F.; Martin, N. F.; McConnachie, A. W.; Veljanoski, J.; Mackey, A. D.; Ferguson, A. M. N.; Ibata, R. A.; Irwin, M. J.; Fardal, M.; et al. (Monthly Notices of the Royal Astronomical Society, 2013)
We undertake the first detailed analysis of the stellar population and spatial properties of a diffuse substructure in the outer halo ofM31. The South-West Cloud lies at a projected distance of ̃100 kpc from the centre of M31 and extends for at least ̃50 kpc in projection. We use Pan-Andromeda Archaeological Survey photometry of red giant branch stars to determine a distance to the South-West Cloud of 793+45 -45 kpc. The metallicity of the cloud is found to be [Fe/H] = -1.3 ± 0.1. This is consistent with the coincident globular clusters PAndAS-7 and PAndAS-8, which have metallicities determined using an independent technique of [Fe/H] = -1.35 ± 0.15. We measure a brightness for the Cloud of MV = -12.1 mag; this is ̃75 per cent of the luminosity implied by the luminosity-metallicity relation. Under the assumption that the South-West Cloud is the visible remnant of an accreted dwarf satellite, this suggests that the progenitor object was amongst M31's brightest dwarf galaxies prior to disruption. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

The investigation of the triaxial residual stress in the friction stir welded lap joint using neutron diffraction - Bach, Michael; Merati, Ali; Gharghouri, Michal; Rogge, Ronald; Bell, Robert; Wang, Xin (International Conference on Residual Stresses 9 (ICRS 9), 2013)
A detailed study of the complex triaxial residual stress distribution of the double-pass friction stir welded (FSW) lap-joint between two different high strength aluminum alloy sheet materials was conducted. A non-destructive technique known as neutron diffraction was used to measure the internal residual stress distribution in the three principal direction of the lap-joint in the as-welded and hammer peened configurations to determine effects of hammer peening on redistribution of residual stresses across the weld. The residual stress variation across the weld in the transverse direction contained the highest values of tensile stress in all three principal directions. The residual stress in the hammer peened test specimen was in most cases reduced in all three principal directions.
Keywords: Double pass; Friction stir; High strength aluminum alloys; Lap joint; Non-destructive technique; Principal directions; Stress variations; Test specimens; Friction stir welding; Hammers; Neutron diffraction; Nondestructive examination; Stress concentration; Welds; Residual stresses

Si nanotubes ALD coated with TiO2, TiN or Al2O 3 as high performance lithium ion battery anodes - Lotfabad, Elmira Memarzadeh; Kalisvaart, Peter; Kohandehghan, Alireza; Cui, Kai; Kupsta, Martin; Farbod, Behdokht; Mitlin, David (Journal of Materials Chemistry A, 2013)
Silicon based hollow nanostructures are receiving significant scientific attention as potential high energy density anodes for lithium ion batteries. However their cycling performance still requires further improvement. Here we explore the use of atomic layer deposition (ALD) of TiO2, TiN and Al2O3 on the inner, the outer, or both surfaces of hollow Si nanotubes (SiNTs) for improving their cycling performance. We demonstrate that all three materials enhance the cycling performance, with optimum performance being achieved for SiNTs conformally coated on both sides with 1.5 nm of Li active TiO2. Substantial improvements are achieved in the cycling capacity retention (1700 mA h g-1vs. 1287 mA h g-1 for the uncoated baseline, after 200 cycles at 0.2 C), steady-state coulombic efficiency (∼100% vs. 97-98%), and high rate capability (capacity retention of 50% vs. 20%, going from 0.2 C to 5 C). TEM and other analytical techniques are employed to provide new insight into the lithiation cycling-induced failure mechanisms that turn out to be intimately linked to the microstructure and the location of these layers.

Chirp-wave expansion of the electron wavefunctions in atoms - Torres, Edmanuel; Torres, Rafael (Journal of Computational and Applied Mathematics, 2013)
The description of the electron wavefunctions in atoms is generalized to the fractional Fourier series. This method introduces a continuous and infinite number of chirp basis sets with linear variation of the frequency to expand the wavefunctions, in which plane-waves are a special case. The chirp characteristics of each basis set can be adjusted through a single parameter. Thus, the basis set cutoff can be optimized variationally. The approach is tested with the expansion of the electron wavefunctions in atoms, and it is shown that chirp basis sets substantially improve the convergence in the description of the electron density. We have found that the natural oscillations of the electron core states are efficiently described in chirp-waves.
Keywords: Basis sets; Chirp series; Electron wavefunctions; Fractional Fourier series; Fractional Fourier transforms; Gauge transformation; Infinite numbers; Natural oscillation; Atoms; Fourier series; Electrons

Spectroelectrochemistry of FeIII- and CoIII- mimochrome VI artificial enzymes immobilized on mesoporous ITO electrodes - Vitale, R.; Lista, L.; Lau-Truong, S.; Tucker, R. T.; Brett, M. J.; Limoges, B.; Pavone, V.; Lombardi, A.; Balland, V. (Chemical Communications, 2013)
UV-visible absorption spectroelectrochemistry elucidated the different redox behaviours of FeIII- and CoIII-mimochrome VI artificial enzymes, adsorbed on mesoporous conductive films of ITO. The reduction of the ferric complex was rapid and reversible, while the cobaltic complex exhibited irreversible processes probably related to multiple coordination states.

The calcium-sensing receptor R990G polymorphism is associated with increased risk of hypertriglyceridemia in obese Chinese - He, Yong-han; Kong, Wei-lan; Wang, Guan; Zhao, Yue; Bi, Ming-xin; Na, Li-xin; Wang, Mao-qing; Perry, Ben; Li, Ying (Gene, 2013)
Background: We have demonstrated that the calcium-sensing receptor (CaSR) is involved in lipid metabolism; however, whether CaSR polymorphisms affect lipid metabolism in obesity is still unclear. The present study aimed to determine the effects of CaSR polymorphisms on HTG risk in obese Chinese. Methods: A total of 972 subjects with HTG and 1197 with normal triglyceride (NTG) were stratified by body mass index (BMI) into normal weight, overweight or obesity subgroups. After 12-h fasting, CaSR polymorphisms in exon 7 were determined in the blood. Serum lipids and glucose, as well as height, body weight and waist circumference were measured. The anthropometric and metabolic characteristics of the NTG subjects were re-evaluated 3. years later. Results: There were no genotypic or allelic distribution differences for the A986S or Q1011E polymorphisms between the NTG and HTG groups. However, the G/G genotypic and G allelic distributions of the CaSR R990G polymorphism in the HTG group were higher than the NTG group (p<. 0.001). After stratification, in obese subjects, the homozygous (G/G) distribution of the CaSR R990G polymorphism in the HTG group was significantly higher than in the NTG group (p= 0.001), and showed an increased risk of HTG at baseline [OR. = 2.55, 95% CI. = 1.65-3.92, p<. 0.006]. Interaction of the CaSR R990G polymorphism with BMI was associated with increased risk of HTG (β= 0.927, p< 0.001). Re-evaluation of the NTG subjects revealed significantly increased serum triglyceride levels in obese homozygous versus wildtype carriers (p< 0.05). Conclusions: These results suggest that the CaSR R990G polymorphism is associated with increased risk of HTG, especially in obese Chinese, and may be a potential genetic predictor of diseases related to HTG. •The CaSR polymorphisms were determined in 2169 subjects.
Keywords: calcium sensing receptor; triacylglycerol; adult; aged; article; body mass; Chinese; controlled study; exon; female; gene frequency; genetic association; genetic polymorphism; genetic risk; genotype; high risk population; homozygosity; human; hypertriglyceridemia; major clinical study; male; obesity; pathogenesis; priority journal; triacylglycerol blood level

Pleurocidin, a novel antimicrobial peptide, induces human mast cell activation through the FPRL1 receptor - Pundir, P.; Catalli, A.; Leggiadro, C.; Douglas, S. E.; Kulka, M. (Mucosal Immunology, 2013)
Pleurocidins are a novel family of α-helical cationic antimicrobial peptides (CAPs) that are structurally and functionally similar to cathelicidins, one of the major CAP families. As cathelicidins stimulate mast cell chemotaxis and mediator release, we postulated that pleurocidins similarly activate mast cells. A screen of 20 pleurocidin peptides revealed that some were capable of degranulating the human mast cell line LAD2 (Laboratory of Allergic Diseases 2). Pleurocidin NRC-04 caused LAD2 to adhere, migrate, degranulate, and release cysteinyl leukotrienes and prostaglandin D2. Moreover, pleurocidin increased intracellular Ca2+ mobilization in mast cells and induced the production of proinflammatory chemokines such as monocyte chemotactic protein-1/C-C motif chemokine ligand 2 (CCL2) and macrophage inflammatory protein-1β/CCL4. Our evaluation of possible cellular mechanisms suggested that G proteins, phosphoinositol-3 kinase (PI3K), phospholipase C (PLC), and phosphokinase C (PKC) were involved in pleurocidin-induced mast cell activation as evidenced by the inhibitory effects of pertussis toxin (G protein inhibitor), wortmanin (PI3K inhibitor), U-73122 (PLC inhibitor), and Ro-31-8220 (PKC inhibitor), respectively. We also found that human mast cells expressed the N-formyl-peptide receptor 1 (FPRL1) receptor and FPRL1-specific inhibitor affected pleurocidin-mediated activation of mast cell. Our finding that the novel CAP pleurocidin activated human mast cell through G protein-coupled receptor signaling suggests that this peptide might have immunomodulatory functions. © 2014 Society for Mucosal Immunology.

Isolated microspore culture of oat (Avena sativa L.) for the production of doubled haploids : effect of pre-culture and post-culture conditions - Ferrie, A. M. R.; Irmen, K. I.; Beattie, A. D.; Rossnagel, B. G. (Plant Cell, Tissue and Organ Culture, 2013)
The production of doubled haploid (DH) plants from microspores is an important technique used in plant breeding programs and basic research. Although doubled haploidy efficiencies in wheat and barley are sufficient for breeding purposes, oat (Avena sativa L.) is considered recalcitrant. The objective of this project was to develop a protocol for the production of microspore-derived embryos of oat and further develop these embryos into fertile DH plants. A number of experiments were conducted evaluating the factors influencing microspore embryogenesis, i.e. donor plant conditions, pretreatments, media composition, and culture conditions. The initial studies yielded little response, and it was not until high microspore densities (106 microspores/mL and greater) were used that embryogenesis was achieved. Depending on the treatment, yields of over 5,000 embryos/106 microspores were obtained for breeding line 2000QiON43. The doubled haploidy protocol includes: a 0.3 M mannitol pretreatment of the tillers for 7 days, culture in W14 basal medium with a pH of 6.5-7.5, a microspore density of 106 microspores/mL, and continuous incubation at 28 °C incubation. The resulting embryos observed after 28 days were plated onto solidified W14 medium with 0.8 or 1.0 g/L activated charcoal. A colchicine treatment of 0.2 % colchicine for 4 h resulted in conversion of 80 % of the plants from haploid to DH. This protocol was successful for the production of oat microspore-derived embryos and DH green plants with minimal albinism. DH seed was produced and planted for evaluation in a field nursery.
Keywords: Avena sativa; Culture conditions; Doubled haploid; Media composition; Microspore culture; Microspore embryogenesis; Oat; Plant breeding programs; Cell culture; Plants (botany); Seed

Lipid-coated gold nanoparticles promote lamellar body formation in A549 cells - Wang, Meijing; Petersen, Nils O. (Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids, 2013)
Gold nanoparticles (GNPs) have been applied as diagnostic and therapeutic agents because they can be targeted, localized, and be heated to cause cell death. However, their use has been limited by their relatively low biocompatibility. In this work, we coated the GNPs' surface by a biocompatible phospholipid bilayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phospho- (1′-rac-glycerol) (SOPG). We tested their interaction with A549 cells to investigate their uptake and intracellular fate as well as the response of the cells to the presence of the GNPs. We used flow cytometry and confocal microscopy to show that the SOPG coated GNPs were readily taken up by the A549 cells. Transmission electron microscopy (TEM) images and fluorescence images further showed that the number of granular structures in the cells was increased following exposure to the lipid coated GNPs. Co-localization experiments demonstrated that SOPG coated GNPs localize in acidic compartments in a time dependent manner and that the number of these increase as the cells are exposed to the GNPs suggesting that they induce formation of lamellar bodies (LBs) which in A549 cells in turn can serve as a means of exporting the GNPs.
Keywords: Phospholipid; 1-stearoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (SOPG); Gold nanoparticle; Endocytosis; A549 cell; Lamellar bodies (LBs)

The DiskMass Survey: VII. the distribution of luminous and dark matter in spiral galaxies - Martinsson, Thomas P. K.; Verheijen, Marc A. W.; Westfall, Kyle B.; Bershady, Matthew A.; Andersen, David R.; Swaters, Rob A. (Astronomy and Astrophysics, 2013)
We present dynamically-determined rotation-curve mass decompositions of 30 spiral galaxies, which were carried out to test the maximum-disk hypothesis and to quantify properties of their dark-matter halos.We used measured vertical velocity dispersions of the disk stars to calculate dynamical mass surface densities (σdyn). By subtracting our observed atomic and inferred molecular gas mass surface densities from σdyn, we derived the stellar mass surface densities (σ+), and thus have absolute measurements of all dominant baryonic components of the galaxies. Using K-band surface brightness profiles (IK), we calculated the K-band mass-to-light ratio of the stellar disks (γ+ = σ+/IK) and adopted the radial mean (γ) for each galaxy to extrapolate σ+ beyond the outermost kinematic measurement. The derived γ of individual galaxies are consistent with all galaxies in the sample having equal γ. We find a sample average and scatter of -γ- = 0.31 α 0.07. Rotation curves of the baryonic components were calculated from their deprojected mass surface densities. These were used with circular-speed measurements to derive the structural parameters of the dark-matter halos, modeled as either a pseudo-isothermal sphere (pISO) or a Navarro-Frenk-White (NFW) halo. In addition to our dynamically determined mass decompositions, we also performed alternative rotation-curve decompositions by adopting the traditional maximumdisk hypothesis. However, the galaxies in our sample are submaximal, such that at 2.2 disk scale lengths (hR) the ratios between the baryonic and total rotation curves (F 2.2hR b ) are less than 0.75. We find this ratio to be nearly constant between 1-6hR within individual galaxies. We find a sample average and scatter of -F 2.2hR b - = 0.57 α 0.07, with trends of larger F 2.2hR b for more luminous and higher-surface-brightness galaxies. To enforce these being maximal, we need to scale γ+ by a factor 3.6 on average. In general, the dark-matter rotation curves are marginally better fit by a pISO than by an NFWhalo. For the nominal-γ+ (submaximal) case, we find that the derived NFW-halo parameters have values consistent with δCDM N-body simulations, suggesting that the baryonic matter in our sample of galaxies has only had a minor effect on the dark-matter distribution. In contrast, maximum-γ+ decompositions yield halo-concentration parameters that are too low compared to the δCDM simulations.
Keywords: Fundamental parameters; Imaging spectroscopy; Kinematics and dynamics; Spiral; Techniques; Kinematics; Luminance; Rotation; Stars; Structure (composition); Galaxies

The Carina project. VI. The helium-burning variable stars - Coppola, G.; Stetson, P. B.; Marconi, M.; Bono, G.; Ripepi, V.; Fabrizio, M.; Dall'Ora, M.; Musella, I.; Buonanno, R.; Ferraro, I.; Fiorentino, G.; Iannicola, G.; et al. (The Astrophysical Journal, 2013)
We present new optical (BVI) time-series data for the evolved variable stars in the Carina dwarf spheroidal galaxy. The quality of the data and the observing strategy allowed us to identify 14 new variable stars. Eight out of the 14 are RR Lyrae (RRL) stars, 4 are Anomalous Cepheids (ACs), and 2 are geometrical variables. Comparison of the period distribution for the entire sample of RRLs with similar distributions in nearby dwarf spheroidal galaxies and in the Large Magellanic Cloud indicates that the old stellar populations in these systems share similar properties. This finding is also supported by the RRL distribution in the Bailey diagram. On the other hand, the period distribution and the Bailey diagram of ACs display significant differences among the above stellar systems. This evidence suggests that the properties of intermediate-age stellar populations might be affected both by environmental effects and structural parameters. We use the BV Period-Wesenheit (PW) relation of RRLs together with evolutionary prescriptions and find a true distance modulus of 20.09 ± 0.07 (intrinsic) ± 0.1 (statistical) mag that agrees quite well with similar estimates available in the literature. We identified four peculiar variables. Taking into account their position in the Bailey diagram and in the BV PW relation, two of them (V14 and V149) appear to be candidate ACs, while two (V158 and V182) might be peculiar RRLs. In particular, the variable V158 has a period and a V-band amplitude very similar to the low-mass RRL - RRLR-02792 - recently identified by Pietrzyński et al. in the Galactic bulge.

The PAndAS view of the andromeda satellite system. I. A Bayesian search for dwarf galaxies using spatial and color-magnitude information - Martin, Nicolas F.; Ibata, Rodrigo A.; McConnachie, Alan W.; Mackey, A. Dougal; Ferguson, Annette M. N.; Irwin, Michael J.; Lewis, Geraint F.; Fardal, Mark A. (The Astrophysical Journal, 2013)
We present a generic algorithm to search for dwarf galaxies in photometric catalogs and apply it to the Pan-Andromeda Archaeological Survey (PAndAS). The algorithm is developed in a Bayesian framework and, contrary to most dwarf galaxy search codes, makes use of both the spatial and color-magnitude information of sources in a probabilistic approach. Accounting for the significant contamination from the Milky Way foreground and from the structured stellar halo of the Andromeda galaxy, we recover all known dwarf galaxies in the PAndAS footprint with high significance, even for the least luminous ones. Some Andromeda globular clusters are also recovered and, in one case, discovered. We publish a list of the 143 most significant detections yielded by the algorithm. The combined properties of the 39 most significant isolated detections show hints that at least some of these trace genuine dwarf galaxies, too faint to be individually detected. Follow-up observations by the community are mandatory to establish which are real members of the Andromeda satellite system. The search technique presented here will be used in an upcoming contribution to determine the PAndAS completeness limits for dwarf galaxies. Although here tuned to the search of dwarf galaxies in the PAndAS data, the algorithm can easily be adapted to the search for any localized overdensity whose properties can be modeled reliably in the parameter space of any catalog.

The DiskMass Survey: VI. Gas and stellar kinematics in spiral galaxies from PPak integral-field spectroscopy - Martinsson, Thomas P. K.; Verheijen, Marc A. W.; Westfall, Kyle B.; Bershady, Matthhew A.; Schechtman-Rook, Andrew; Andersen, David R.; Swaters, Rob A. (Astronomy and Astrophysics, 2013)
We present ionized-gas ([Oiii]λ5007 Å) and stellar kinematics (velocities and velocity dispersions) for 30 nearly face-on spiral galaxies out to as many as three K-band disk scale lengths (hR). These data have been derived from PPak integral-field-unit spectroscopy from 4980−5370 Å observed at a mean resolution of λ/Δλ = 7700 (σinst = 17 km s-1). These data are a fundamental product of our survey and will be used in companion papers to, e.g., derive the detailed (baryonic+dark) mass budget of each galaxy in our sample. Our presentation provides a comprehensive description of the observing strategy and data reduction, including a robust measurement and removal of shift, scale, and rotation effects in the data due to instrumental flexure. Using an in-plane coordinate system determined by fitting circular-speed curves to our velocity fields, we derive azimuthally averaged rotation curves and line-of-sight velocity dispersion (σLOS) and luminosity profiles for both the stars and [Oiii]-emitting gas. Along with a clear presentation of the data, we demonstrate: (1) The [Oiii] and stellar rotation curves exhibit a clear signature of asymmetric drift with a rotation difference that is 11% of the maximum rotation speed of the galaxy disk, comparable to measurements in the solar neighborhood in the Milky Way. (2) The e-folding length of the stellar velocity dispersion (hσ) is 2hR on average, as expected for a disk with a constant scale height and mass-to-light ratio, with a scatter that is notably smaller for massive, high-surface-brightness disks in the most luminous galaxies. (3) At radii larger than 1.5hR, σLOS tends to decline slower than the best-fitting exponential function, which may be due to an increase in the disk mass-to-light ratio, disk flaring, or disk heating by the dark-matter halo. (4) A strong correlation exists between the central vertical stellar velocity dispersion of the disks (σz,0) and their circular rotational speed at 2.2hR (V2.2hROiii), with a zero point indicating that galaxy disks are submaximal. Moreover, weak but consistent correlations exist between σz,0/V2.2hROiii and global galaxy properties such that disks with a fainter central surface brightness in bluer and less luminous galaxies of later morphological types are kinematically colder with respect to their rotational velocities.
Keywords: Fundamental parameters; Imaging spectroscopy; Kinematics and dynamics; Spiral; Techniques; Curve fitting; Dispersions; Galaxies; Ionization of gases; Kinematics; Luminance; Stars; Structure (composition); Surveys; Velocity; Rotating disks

A normal abundance of faint satellites in the fossil group NGC 6482 - Lieder, S.; Mieske, S.; Sánchez-Janssen, R.; Hilker, M.; Lisker, T.; Tanaka, M. (Astronomy and Astrophysics, 2013)
A fossil group is considered the end product in a galaxy group's evolution. It is a massive central galaxy that dominates the luminosity budget of the group, and is the outcome of efficient merging between intermediate-luminosity members. Little is known, however, about the faint satellite systems of fossil groups. Here we present a Subaru/Suprime-Cam wide-field, deep imaging study in the B-and R-bands of the nearest fossil group NGC 6482 (Mtot ~ 4 × 1012MâŠ™), covering the virial radius out to 310 kpc. We performed detailed completeness estimations and selected group member candidates by a combination of automated object detection and visual inspection. A fiducial sample of 48 member candidates down to M R ~-10.5 mag is detected, making this study the deepest of a fossil group to now. We investigate the photometric scaling relations, the color-magnitude relation, and the luminosity function of our galaxy sample. We find evidence of recent and ongoing merger events among bright group galaxies. The color-magnitude relation is comparable to that of nearby galaxy clusters, and it exhibits significant scatter at the faintest luminosities. The completeness-corrected luminosity function is dominated by early-type dwarfs and is characterized by a faint end slope α =-1.32 ± 0.05. We conclude that the NGC 6482 fossil group shows photometric properties consistent with those of regular galaxy clusters and groups, including a normal abundance of faint satellites.

Composite spectra XIX: HD 208253, a long-period binary whose hot secondary has enhanced strontium and barium - Griffin, R. E. M.; Griffin, R. F. (Astronomische Nachrichten, 2013)
We separate and analyse the component spectra of the composite-spectrum binary HD 208253. We find that the cool primary is an evolving star of spectral type G7 III, while its hot secondary is an early-A dwarf. The giant is currently near the lowest point of the red-giant branch and is slightly less luminous than its dwarf companion. We provide a set of precise radial-velocity measurements for both stars. The double-lined orbit which we derive from them shows that the component mass ratio is close to unity (q = 1.05 ± 0.01). We deduce the physical properties of both stars, determine their respective masses to be 2.75 ± 0.07 Me (giant) and 2.62 ± 0.07 Me (dwarf), and show that the orbit's inclination is within a degree or two of 68°. The spectrum of the A-type component has quite component has quite narrow lines (we infer a rotational velocity of 18 km s-1), though since the period of the orbit is well over 1 year that component cannot be in synchronous rotation. An intriguing property of the dwarf is its enhanced Sr and Ba, though it does not exhibit the other spectral peculiarities that would signal a classical Am star. While by no means unique amongst the multitude of oddities exhibited by A and early-F stars, this dwarf which we have uncovered in a long-period binary offers valuable constraints and challenges to stellar-evolution theory.
Keywords: binaries: spectroscopic; stars: chemically peculiar; stars: fundamental parameters; stars: individual (HD 208253)

Characterization of atomic structure of oxide films on carbon steel in simulated concrete pore solutions using EELS - Gunay, H. Burak; Ghods, Pouria; Isgor, O. Burkan; Carpenter, Graham J. C.; Wu, Xiaohua (Applied Surface Science, 2013)
The atomic structure of oxide films formed on carbon steel that are exposed to highly alkaline simulated concrete pore solutions was investigated using Electron Energy Loss Spectroscopy (EELS). In particular, the effect of chloride exposure on film structure was studied in two types of simulated pore solutions: saturated calcium hydroxide (CH) and a solution prepared to represent typical concrete pore solutions (CP). It was shown that the films that form on carbon steel in simulated concrete pore solutions contained three indistinct layers. The inner oxide film had a structure similar to that of FeIIO, which is known to be unstable in the presence of chlorides. The outer oxide film mainly resembled Fe3O4 (FeIIO·Fe 2 IIIO3) in the CH solution and α-Fe 2 IIIO3/Fe3O4 in the CP solution. The composition of the transition layer between the inner and outer layers of the oxide film was mainly composed of Fe3O4 (FeIIO·Fe2 IIIO3). In the presence of chloride, the relative amount of the FeIII/Fe II increased, confirming that chlorides induce valence state transformation of oxides from FeII to FeIII, and the difference between the atomic structures of oxide film layers diminished.
Keywords: Chloride; Concrete pore solutions; Film structure; Passive films; Pore solution; Simulated concrete pore solution; Transition layers; Valence state; Carbon steel; Chlorine compounds; Concretes; Corrosion; Electron energy loss spectroscopy; Oxide films

Nanoscale torsional optomechanics - Kim, P. H.; Doolin, C.; Hauer, B. D.; MacDonald, A. J. R.; Freeman, M. R.; Barclay, P. E.; Davis, J. P. (Applied Physics Letters, 2013)
Keywords: Fiber-based systems; Integrated device; Microdisk whispering galleries; Nano scale; Noise floor; On chips; Optical fiber probe; Opto-mechanics; Optomechanical; Physical measurement; Torsional resonator; Optical fibers; Resonators; Nanotechnology

Astronomical seeing and ground-layer turbulence in the Canadian high Arctic - Hickson, P.; Gagné, R.; Pfrommer, T.; Steinbring, E. (Monthly Notices of the Royal Astronomical Society, 2013)
We report results of a two-year campaign of measurements, during arctic winter darkness, of optical turbulence in the atmospheric boundary layer above the Polar Environment Atmospheric Laboratory in northern Ellesmere Island (latitude +80° N). The data reveal that the ground-layer turbulence in the Arctic is often quite weak, even at the comparatively low 610 m altitude of this site. The median and 25th percentile ground-layer seeing, at a height of 20 m, are found to be 0.57 and 0.25 arcsec, respectively. When combined with a free-atmosphere component of 0.30 arcsec, the median and 25th percentile total seeing for this height is 0.68 and 0.42 arcsec, respectively. The median total seeing from a height of 7 m is estimated to be 0.81 arcsec. These values are comparable to those found at the best high-altitude astronomical sites. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Toward quantum processing in molecules: A THz-bandwidth coherent memory for light - Bustard, P.J.; Lausten, R.; England, D.G.; Sussman, B.J. (Physical Review Letters, 2013)
The unusual features of quantum mechanics are enabling the development of technologies not possible with classical physics. These devices utilize nonclassical phenomena in the states of atoms, ions, and solid-state media as the basis for many prototypes. Here we investigate molecular states as a distinct alternative. We demonstrate a memory for light based on storing photons in the vibrations of hydrogen molecules. The THz-bandwidth molecular memory is used to store 100-fs pulses for durations up to ∼1 ns, enabling ∼104 operational time bins. The results demonstrate the promise of molecules for constructing compact ultrafast quantum photonic technologies. Published by the American Physical Society.
Keywords: Classical physics; Hydrogen molecule; Molecular memory; Molecular state; Physical societies; Quantum photonics; Ultra-fast; Bandwidth; Light; Quantum theory; Molecules

Lipopolysaccharide structure of Helicobacter pylori serogroup O:3 - Altman, E.; Chandan, V.; Li, J.; Vinogradov, E. (Carbohydrate Research, 2013)
In this study, we describe a re-investigation of the lipopolysaccharide structure of Helicobacter pylori serogroup O:3. Application of NMR and MS approaches to the analysis of oligosaccharides obtained through degradation of LPS from H. pylori serogroup O:3 by various methods confirmed that its general architecture was identical to that of LPS from H. pylori strains 26695 and SS1 and followed a sequential linear assembly of the α-1,6-glucan, DD-heptan, and O-chain components. Additionally, MALDI-MS analysis demonstrated that a significant proportion of H. pylori serogroup O:3 LPS was terminated with α-1,6-glucan and was not further substituted by DD-heptan and the O-chain polysaccharide. Crown Copyright © 2013 Published by Elsevier Ltd.
Keywords: General architectures; Helicobacter pylori; Linear assembly; Lipopolysaccharides; LPS; MALDI-MS; MS; O-Chain; Nuclear magnetic resonance; Organic compounds; Structure (composition); Synthesis (chemical); Chains; bacterium lipopolysaccharide; dextran; heptane; oligosaccharide; oxygen; polysaccharide; analytic method; animal cell; article; bacterial strain; biodegradation; carbohydrate analysis; chemical composition; controlled study; Helicobacter pylori; mass spectrometry; matrix assisted laser desorption ionization time of flight mass spectrometry; nonhuman; nuclear magnetic resonance spectroscopy; priority journal; substitution reaction; Helicobacter pylori