bluuebunny/crossref_metadata_2025 huggingface dataset:
The spectroscopy and photochemistry of quinioline structural isomers: (E)- and (Z)-phenylvinylnitrile
Authors: Mehta-Hurt Deepali N. , Korn Joseph A. , Navotnaya Polina , Parobek Alexander P. , Clayton Rachel M. , Zwier Timothy S.
Published: August 2015

In Titan’s atmosphere, photochemical pathways that lead to nitrogen heteroaromatics may incorporate photoisomerization of their structural isomers as a final step. (E)- and (Z)-phenylvinylnitrile ((E)- and (Z)-PVN, C6H5 —CH=CHCN) are structural isomers of quinoline that themselves possess extensive absorptions in the ultraviolet, and thus may engage in such photoisomerization pathways. The present study explores the vibronic spectroscopy and photo-induced isomerization of gas-phase (E)- and (Z)-PVN in the 33,600-35,850 cm−1 region under jet-cooled conditions. The S0-S1 origins for (E)- and (Z)-PVN have been identified at 33 827 cm−1 and 33 707 cm−1, respectively. Isomer-specific UV-UV hole-burning and UV depletion spectra reveal sharp vibronic structure that extends over almost 2000 cm−1, with thresholds for fast non-radiative decay identified by a comparison between hole-burning and UV depletion spectra. Dispersed fluorescence spectra of the two isomers enable the assignment of many low frequency transitions in both molecules, aided by harmonic frequency calculations (B3LYP/6-311++G(d,p)) and a comparison with the established spectroscopy of phenylvinylacetylene, the ethynyl counterpart to PVN. Both isomers are proven to be planar in both the S0 ground and S1 electronic excited states. (E)-PVN exhibits extensive Duschinsky mixing involving out-of-plane modes whose frequencies and character change significantly in the ππ∗ transition, which modulates the degree of single- and double-bond character along the vinylnitrile substituent. This same mixing is much less evident in (Z)-PVN. The spectroscopic characterization of (E)- and (Z)-PVN served as the basis for photoisomerization experiments using ultraviolet hole-filling spectroscopy carried out in a reaction tube affixed to the pulsed valve. Successful interconversion between (E) and (Z)-PVN was demonstrated via ultraviolet hole-filling experiments. Photoexcitation of (E)- and (Z)-PVN at their respective S0-S1 origins failed to produce quinoline, a simple polycyclic aromatic nitrogen heterocylcle, within the detection sensitivity of our experiments. Stationary points along the potential energy surface associated with (Z)-PVN → quinoline isomerization showed a barrier of 93 kcal/mol associated with the first step in the isomerization process, slowing the interconversion process at the excitation energies used (96 kcal/mol) to timescales beyond those probed in the present experiment.
Accurate ab initio-based double many-body expansion potential energy surface for the adiabatic ground-state of the C3 radical including combined Jahn-Teller plus pseudo-Jahn-Teller interactions
Authors: Rocha C. M. R. , Varandas A. J. C.
Published: August 2015

A fully ab initio-based potential energy surface is first reported for the ground electronic state of the C3 radical using the double many-body expansion (DMBE) method. The DMBE form so obtained mimics the full set of energies calculated at the multireference configuration interaction level of theory with chemical accuracy. To account for the incompleteness of the one- and N-electron bases, the calculated external correlation energies have been scaled prior to the fitting procedure via DMBE-scaled external correlation method. Furthermore, the novel potential energy surface reproduces accurately dissociation energies, diatomic potentials, long-range interactions at all asymptotic channels, and the correct topological behavior at the region of 4 conical intersections with the partner state of the same symmetry near equilateral triangular geometries due to combined Jahn-Teller (E′ ⊗ e′) plus pseudo-Jahn-Teller [(E′+A1′)⊗e′] interactions. Rovibrational calculations have also been performed, unveiling a good match of the vibrational spectrum of C3 for 53 calculated levels. The present DMBE form is, therefore, commended for both spectroscopic and reaction dynamics studies, some also performed in the present work.
Pressure-induced transformations in glassy water: A computer simulation study using the TIP4P/2005 model
Authors: Wong Jessina , Jahn David A. , Giovambattista Nicolas
Published: August 2015

We study the pressure-induced transformations between low-density amorphous (LDA) and high-density amorphous (HDA) ice by performing out-of-equilibrium molecular dynamics (MD) simulations. We employ the TIP4P/2005 water model and show that this model reproduces qualitatively the LDA-HDA transformations observed experimentally. Specifically, the TIP4P/2005 model reproduces remarkably well the (i) structure (OO, OH, and HH radial distribution functions) and (ii) densities of LDA and HDA at P = 0.1 MPa and T = 80 K, as well as (iii) the qualitative behavior of ρ(P) during compression-induced LDA-to-HDA and decompression-induced HDA-to-LDA transformations. At the rates explored, the HDA-to-LDA transformation is less pronounced than in experiments. By studying the LDA-HDA transformations for a broad range of compression/decompression temperatures, we construct a “P–T phase diagram” for glassy water that is consistent with experiments and remarkably similar to that reported previously for ST2 water. This phase diagram is not inconsistent with the possibility of TIP4P/2005 water exhibiting a liquid-liquid phase transition at low temperatures. A comparison with previous MD simulation studies of SPC/E and ST2 water as well as experiments indicates that, overall, the TIP4P/2005 model performs better than the SPC/E and ST2 models. The effects of cooling and compression rates as well as aging on our MD simulations results are also discussed. The MD results are qualitatively robust under variations of cooling/compression rates (accessible in simulations) and are not affected by aging the hyperquenched glass for at least 1 μs. A byproduct of this work is the calculation of TIP4P/2005 water’s diffusion coefficient D(T) at P = 0.1 MPa. It is found that, for T ≥ 210 K, D(T) ≈ (T − TMCT)−γ as predicted by mode coupling theory and in agreement with experiments. For TIP4P/2005 water, TMCT = 209 K and γ = 2.14, very close to the corresponding experimental values TMCT = 221 K and γ = 2.2.
Fast internal dynamics in alcohol dehydrogenase
Authors: Monkenbusch M. , Stadler A. , Biehl R. , Ollivier J. , Zamponi M. , Richter D.
Published: August 2015

Large-scale domain motions in alcohol dehydrogenase (ADH) have been observed previously by neutron spin-echo spectroscopy (NSE). We have extended the investigation on the dynamics of ADH in solution by using high-resolution neutron time-of-flight (TOF) and neutron backscattering (BS) spectroscopy in the incoherent scattering range. The observed hydrogen dynamics were interpreted in terms of three mobility classes, which allowed a simultaneous description of the measured TOF and BS spectra. In addition to the slow global protein diffusion and domain motions observed by NSE, a fast internal process could be identified. Around one third of the protons in ADH participate in the fast localized diffusive motion. The diffusion coefficient of the fast internal motions is around two third of the value of the surrounding D2O solvent. It is tempting to associate the fast internal process with solvent exposed amino acid residues with dangling side chains.
Thermal conductivity variation of graphene with patterned double-side hydrogen doping
Authors: Li Chengjian , Li Gang , Zhao Huijuan
Published: August 2015

Using non-equilibrium molecular dynamics simulations, we investigate the thermal conductivity variation of graphene with different hydrogen doping coverage and doping orientation. It shows that the thermal conductivity of graphene decreases with increasing hydrogen doping coverage. The decreasing rate, however, depends on the doping orientation. Based on the kinetic theory of lattice thermal transport, we study the effect of doping coverage and orientation on the phonon density of states, phonon dispersion relation, phonon relaxation time, and the specific heat. While hydrogen doping has little effect on the specific heat, it decreases the phonon group velocity and increases phonon-phonon scattering in graphene. The phonon group velocity reduction is only due to the increment of doping coverage and is independent of doping orientation. A larger angle between the doping stripe orientation and the heat flux direction leads to smaller relaxation times, i.e., stronger phonon-phonon scattering, resulting in a lower thermal conductivity.
Thermal diffusivity anisotropy measured by a temperature wave method in the homologous series of (p-alkoxybenzylidene)-p′-octylaniline (nO.8)
Authors: Uehara Michiru , Takezoe Hideo , Vaupotič Nataša , Pociecha Damian , Gorecka Ewa , Aoki Yoshio , Morikawa Junko
Published: August 2015

The anisotropy of thermal diffusivity in four homologues of (p-alkoxybenzylidene)-p′-octylaniline (nO.8, n = 4 − 7) was measured using a temperature wave method. The results show that the thermal diffusivity component along the director (α∥) is considerably larger than that perpendicular to the director (α⊥) in all mesophases, i.e., nematic (N), smectic A (SmA), smectic B (SmB), and smectic G (SmG) phases. Both components of the thermal diffusivity show a dip at the second- or weakly first-order N-SmA phase transition due to the heat capacity anomaly. In contrast, at the first-order SmA-SmB phase transition, thermal diffusivity exhibits a stepwise increase. The x-ray and calorimetric measurements enable a calculation of the thermal conductivity and the study of the effect of the molecular length on the thermal conductivity and diffusivity in the SmA and SmB phases. For the homologues n = 4, 5, and 6, which exhibit the same phase sequence upon cooling, the parallel component of the thermal conductivity k∥ in the SmA and SmB phases systematically increases with increasing length of the molecular tails, while no such increase is observed in the thermal diffusivity α∥. We thus conclude that the molecular model [Urbach et al., J. Chem. Phys. 78, 5113 (1983)] is valid for the qualitative prediction of the effect of the molecular length on the magnitude of the thermal conductivity.
Should thermostatted ring polymer molecular dynamics be used to calculate thermal reaction rates?
Authors: Hele Timothy J. H. , Suleimanov Yury V.
Published: August 2015

We apply Thermostatted Ring Polymer Molecular Dynamics (TRPMD), a recently proposed approximate quantum dynamics method, to the computation of thermal reaction rates. Its short-time transition-state theory limit is identical to rigorous quantum transition-state theory, and we find that its long-time limit is independent of the location of the dividing surface. TRPMD rate theory is then applied to one-dimensional model systems, the atom-diatom bimolecular reactions H + H2, D + MuH, and F + H2, and the prototypical polyatomic reaction H + CH4. Above the crossover temperature, the TRPMD rate is virtually invariant to the strength of the friction applied to the internal ring-polymer normal modes, and beneath the crossover temperature the TRPMD rate generally decreases with increasing friction, in agreement with the predictions of Kramers theory. We therefore find that TRPMD is approximately equal to, or less accurate than, ring polymer molecular dynamics for symmetric reactions, and for certain asymmetric systems and friction parameters closer to the quantum result, providing a basis for further assessment of the accuracy of this method.
Disorder-induced anomalously signed Hall effect in crystalline GeTe/Sb2Te3 superlattice-like materials
Authors: Tong H. , Yu N. N. , Yang Z. , Cheng X. M. , Miao X. S.
Published: August 2015

Opposite to the almost persistent p-type conductivity of the crystalline chalcogenides along the GeTe-Sb2Te3 tie line, n-type Hall mobility is observed in crystalline GeTe/Sb2Te3 superlattice-like material (SLL) with a short period length. We suggest that this unusual carrier characteristic originates from the structural disorder introduced by the lattice strain and dangling bonds at the SLL interfaces, which makes the crystalline SLLs behave like the amorphous chalcogenides. Detailed structural disorder in crystalline SLL has been studied by Raman scattering, X-ray photoelectron spectroscopy, as well as Variable-energy positron annihilation spectroscopy measurements. First-principles calculations results show that this structural disorder gives rise to three-site junctions that dominate the charge transport as the period length decreases and result in the anomalously signed Hall effect in the crystalline SLL. Our findings indicate a similar tetrahedral structure in the amorphous and crystalline states of SLLs, which can significantly reduce the entropy difference. Due to the reduced entropy loss and increased resistivity of crystalline phase introduced by disorder, it is not surprising that the SLLs exhibit extremely lower RESET current and power consumption.
Constant-complexity stochastic simulation algorithm with optimal binning
Authors: Sanft Kevin R. , Othmer Hans G.
Published: August 2015

At the molecular level, biochemical processes are governed by random interactions between reactant molecules, and the dynamics of such systems are inherently stochastic. When the copy numbers of reactants are large, a deterministic description is adequate, but when they are small, such systems are often modeled as continuous-time Markov jump processes that can be described by the chemical master equation. Gillespie’s Stochastic Simulation Algorithm (SSA) generates exact trajectories of these systems, but the amount of computational work required for each step of the original SSA is proportional to the number of reaction channels, leading to computational complexity that scales linearly with the problem size. The original SSA is therefore inefficient for large problems, which has prompted the development of several alternative formulations with improved scaling properties. We describe an exact SSA that uses a table data structure with event time binning to achieve constant computational complexity with respect to the number of reaction channels for weakly coupled reaction networks. We present a novel adaptive binning strategy and discuss optimal algorithm parameters. We compare the computational efficiency of the algorithm to existing methods and demonstrate excellent scaling for large problems. This method is well suited for generating exact trajectories of large weakly coupled models, including those that can be described by the reaction-diffusion master equation that arises from spatially discretized reaction-diffusion processes.
Improving the prospects of cleavage-based nanopore sequencing engines
Authors: Brady Kyle T. , Reiner Joseph E.
Published: August 2015

Recently proposed methods for DNA sequencing involve the use of cleavage-based enzymes attached to the opening of a nanopore. The idea is that DNA interacting with either an exonuclease or polymerase protein will lead to a small molecule being cleaved near the mouth of the nanopore, and subsequent entry into the pore will yield information about the DNA sequence. The prospects for this approach seem promising, but it has been shown that diffusion related effects impose a limit on the capture probability of molecules by the pore, which limits the efficacy of the technique. Here, we revisit the problem with the goal of optimizing the capture probability via a step decrease in the nucleotide diffusion coefficient between the pore and bulk solutions. It is shown through random walk simulations and a simplified analytical model that decreasing the molecule’s diffusion coefficient in the bulk relative to its value in the pore increases the nucleotide capture probability. Specifically, we show that at sufficiently high applied transmembrane potentials (≥100 mV), increasing the potential by a factor f is equivalent to decreasing the diffusion coefficient ratio Dbulk/Dpore by the same factor f. This suggests a promising route toward implementation of cleavage-based sequencing protocols. We also discuss the feasibility of forming a step function in the diffusion coefficient across the pore-bulk interface.
Fluorinated noble-gas cyanides FKrCN, FXeCN, and FXeNC
Authors: Zhu Cheng , Räsänen Markku , Khriachtchev Leonid
Published: August 2015

We report on three new noble-gas molecules, FKrCN, FXeCN, and FXeNC, prepared in low-temperature Kr and Xe matrices. These molecules are made by UV photolysis of FCN in the matrices and subsequent thermal annealing. The FCN precursor is produced by deposition of the matrix gas containing (FCN)3 through a microwave discharge. The new noble-gas molecules are assigned with the help of quantum chemical calculations at the MP2(full) and CCSD(T) levels of theory. Similar Ar compounds (FArCN and FArNC) as well as FKrNC are not found in these experiments, which is in agreement with the calculated energetics.
Dissipative inertial transport patterns near coherent Lagrangian eddies in the ocean
Authors: Beron-Vera Francisco J. , Olascoaga María J. , Haller George , Farazmand Mohammad , Triñanes Joaquín , Wang Yan
Published: August 2015

Recent developments in dynamical systems theory have revealed long-lived and coherent Lagrangian (i.e., material) eddies in incompressible, satellite-derived surface ocean velocity fields. Paradoxically, observed drifting buoys and floating matter tend to create dissipative-looking patterns near oceanic eddies, which appear to be inconsistent with the conservative fluid particle patterns created by coherent Lagrangian eddies. Here, we show that inclusion of inertial effects (i.e., those produced by the buoyancy and size finiteness of an object) in a rotating two-dimensional incompressible flow context resolves this paradox. Specifically, we obtain that anticyclonic coherent Lagrangian eddies attract (repel) negatively (positively) buoyant finite-size particles, while cyclonic coherent Lagrangian eddies attract (repel) positively (negatively) buoyant finite-size particles. We show how these results explain dissipative-looking satellite-tracked surface drifter and subsurface float trajectories, as well as satellite-derived Sargassum distributions.
Super-radiant plasmon mode is more efficient for SERS than the sub-radiant mode in highly packed 2D gold nanocube arrays
Authors: Mahmoud Mahmoud A.
Published: August 2015

The field coupling in highly packed plasmonic nanoparticle arrays is not localized due to the energy transport via the sub-radiant plasmon modes, which is formed in addition to the regular super-radiant plasmon mode. Unlike the sub-radiant mode, the plasmon field of the super-radiant mode cannot extend over long distances since it decays radiatively with a shorter lifetime. The coupling of the plasmon fields of gold nanocubes (AuNCs) when organized into highly packed 2D arrays was examined experimentally. Multiple plasmon resonance optical peaks are observed for the AuNC arrays and are compared to those calculated using the discrete dipole approximation. The calculated electromagnetic plasmon fields of the arrays displayed high field intensity for the nanocubes located in the center of the arrays for the lower energy super-radiant mode, while the higher energy sub-radiant plasmon mode displayed high field intensity at the edges of the arrays. The Raman signal enhancement by the super-radiant plasmon mode was found to be one hundred fold greater than that by sub-radiant plasmon mode because the super-radiant mode has higher scattering and stronger plasmon field intensity relative to the sub-radiant mode.
Non-superparamagnetic iron-oxide architectures with controlled T2 contrast ability in magnetic resonance imaging
Authors: Ma Ji , Zhang Xiaobing , He Yunhao , Sun Qinglei , Wang Yunguo , Zuo-Jiang Sizhi , Wen Yizhi , Liu Ruiyun , Li Xiaodong , Wang Xingkai , Dong Weifeng , Chen Kezheng
Published: August 2015

In this work, numerous antiferromagnetic (AFM) and weak ferromagnetic (WFM) iron oxides were fabricated and used as contrast agents in magnetic resonance imaging application. These non-superparamagnetic iron oxides exhibit r2/r1 ratios in a range of 20–110, and hence making them potential for T2 contrast enhancers. Most strikingly, a Langevin-function relationship was found between r2/r1 ratios and the specific surface area (S) values, r2/r1 ∼ L−2(S−1), which is quite unique for AFM and WFM iron oxides. This finding enables us to precisely tailor their r2/r1 ratios simply by manipulating their specific surface area via controlling morphology and structure in preparation.
Probing the magnetic moment of FePt micromagnets prepared by focused ion beam milling
Authors: Overweg H. C. , den Haan A. M. J. , Eerkens H. J. , Alkemade P. F. A. , La Rooij A. L. , Spreeuw R. J. C. , Bossoni L. , Oosterkamp T. H.
Published: August 2015

We investigate the degradation of the magnetic moment of a 300 nm thick FePt film induced by Focused Ion Beam (FIB) milling. A 1 μm × 8 μm rod is milled out of a film by a FIB process and is attached to a cantilever by electron beam induced deposition. Its magnetic moment is determined by frequency-shift cantilever magnetometry. We find that the magnetic moment of the rod is μ = 1.1 ± 0.1 × 10−12 Am2, which implies that 70% of the magnetic moment is preserved during the FIB milling process. This result has important implications for atom trapping and magnetic resonance force microscopy, which are addressed in this paper.
Temperature coefficients of phonon frequencies and thermal conductivity in thin black phosphorus layers
Authors: Su Liqin , Zhang Yong
Published: August 2015

We investigate the temperature dependence of three major Raman modes of black phosphorus (BP) prepared by mechanical exfoliation from room temperature to 325 °C. With increasing temperature, all the Raman peaks show redshift in peak position and broadening in linewidth, but they depend on the film thickness. The first-order temperature coefficients of Ag1, B2g, and Ag2 are measured to be −0.0199, −0.0304, and −0.0321 cm−1/K, respectively, in a ∼20-layer film. With decreasing thickness, the temperature coefficient decreases. The average thermal conductivity of a 70-nm thick BP film at room temperature is determined to be 15.8 W/mK when suspended, and 29.2 W/mK when supported on a SiO2/Si substrate. Thermal decomposition temperature is found to be around 350 °C in N2 environment.
Scattering induced by Al segregation in AlGaN/GaN heterostructures
Authors: Liu Xiwen , Ji Dong , Lu Yanwu
Published: August 2015

The effect of Al segregation near dislocations on the mobility of two-dimensional electron gas in AlGaN/GaN heterostructure-based high-electron-mobility transistors was investigated. Exponentially varied composition fluctuation was effective in describing Al segregation near dislocations when calculating scattering behavior. Mobility, which was limited by Al segregation surrounding dislocation lines, was calculated to be in the order of 103 cm2/Vs to 106 cm2/Vs. Results indicated that the mobility in AlGaN/GaN heterojunction was enhanced upon the reduction of dislocation density at low temperature. This study contributes to generating higher electron mobility in AlGaN/GaN heterojunctions.
Gold coated optical fibers as three-dimensional electrodes for microfluidic enzymatic biofuel cells: Toward geometrically enhanced performance
Authors: Desmaële Denis , Renaud Louis , Tingry Sophie
Published: August 2015

For the first time, we report on the preliminary evaluation of gold coated optical fibers (GCOFs) as three-dimensional (3D) electrodes for a membraneless glucose/O2 enzymatic biofuel cell. Two off-the-shelf 125 μm diameter GCOFs were integrated into a 3D microfluidic chip fabricated via rapid prototyping. Using soluble enzymes and a 10 mM glucose solution flowing at an average velocity of 16 mm s−1 along 3 mm long GCOFs, the maximum power density reached 30.0 ± 0.1 μW cm−2 at a current density of 160.6 ± 0.3 μA cm−2. Bundles composed of multiple GCOFs could further enhance these first results while serving as substrates for enzyme immobilization.
Fostering sustainable development at the local-level through international collaboration
Authors: Wang Dongfang , Takai Katherine
Published: August 2015

Sustainable development in a quickly urbanizing and resource-constrained world is more essential now than ever before. There is a chance to lock-in high performance for decades to come as vast new construction efforts are pursued throughout China and around the world. Local governments play a critical leadership role in planning and implementing sustainable development measures, but they may face capacity, resource, and stakeholder buy-in constraints. A comprehensive and well-informed approach is the key to unlocking viable long-term solutions that enhance the quality of life for their constituents. International cooperation in this endeavor can be incredibly transformative, as peers are able to share innovative best practices and information. Development priorities often vary and solutions have to be tailored for their unique context, but there are recurrent winning concepts that can be readily parlayed from one locality to another. This paper explores how the International City/County Management Association and China University of Political Science and Law are leveraging the U.S.-China EcoPartnerships program to amplify sustainable development at the local-level in a number of locations throughout both countries.
White-light-induced disruption of nanoscale conducting filament in hafnia
Authors: Zhou Y. , Yew K. S. , Ang D. S. , Kawashima T. , Bera M. K. , Zhang H. Z. , Bersuker G.
Published: August 2015

Nanoscale conducting filament, which forms the basis of the HfO2 resistive memory, is shown to exhibit a “negative photoconductivity” behavior, in that, electrical conduction through it can be disrupted upon white-light illumination. This behavior should be contrasted against the positive photoconductivity behavior commonly exhibited by oxides or perovskites having narrower bandgaps. The negative photoconductivity effect may be explained in terms of a photon-induced excitation of surrounding oxygen ions, which leads to migration and subsequent recombination with vacancies in the conducting filament. The finding suggests possible electrical-cum-optical applications for HfO2-based devices, whose functionality is limited to-date by electrical stimulation.
Simultaneous desorption behavior of M borohydrides and Mg2FeH6 reactive hydride composites (M = Mg, then Li, Na, K, Ca)
Authors: Chaudhary Anna-Lisa , Li Guanqiao , Matsuo Motoaki , Orimo Shin-ichi , Deledda Stefano , Sørby Magnus H. , Hauback Bjørn C. , Pistidda Claudio , Klassen Thomas , Dornheim Martin
Published: August 2015

Combinations of complex metal borohydrides ball milled with the transition metal complex hydride, Mg2FeH6, are analysed and compared. Initially, the Reactive Hydride Composite (RHC) of Mg2+ cation mixtures of Mg2FeH6 and γ-Mg(BH4)2 is combined in a range of molar ratios and heated to a maximum of 450 °C. For the molar ratio of 6 Mg2FeH6 + Mg(BH4)2, simultaneous desorption of the two hydrides occurred, which resulted in a single event of hydrogen release. This single step desorption occurred at temperatures between those of Mg2FeH6 and γ-Mg(BH4)2. Keeping this anionic ratio constant, the desorption behavior of four other borohydrides, Li-, Na-, K-, and Ca-borohydrides was studied by using materials ball milled with Mg2FeH6 applying the same milling parameters. The mixtures containing Mg-, Li-, and Ca-borohydrides also released hydrogen in a single event. The Mass Spectrometry (MS) results show a double step reaction within a narrow temperature range for both the Na- and K-borohydride mixtures. This phenomenon, observed for the RHC systems at the same anionic ratio with all five light metal borohydride mixtures, can be described as simultaneous hydrogen desorption within a narrow temperature range centered around 300 °C.
Pressure-induced changes in the electron density distribution in α-Ge near the α-β transition
Authors: Li Rui , Liu Jing , Bai Ligang , Tse John S. , Shen Guoyin
Published: August 2015

Electron density distributions in α-Ge have been determined under high pressure using maximum entropy method with structure factors obtained from single crystal synchrotron x-ray diffraction in a diamond anvil cell. The results show that the sp3 bonding is enhanced with increasing pressure up to 7.7(1) GPa. At higher pressures but below the α-β transition pressure of 11.0(1) GPa, the sp3-like electron distribution progressively weakens with a concomitant increase of d-orbitals hybridization. The participation of d-orbitals in the electronic structure is supported by Ge Kβ2 (4p-1s) x-ray emission spectroscopy measurements showing the reduction of 4s character in the valence band at pressures far below the α-β transition. The gradual increase of d-orbitals in the valence level in the stability field of α-Ge is directly related to the eventual structural transition.
Exact solution to the Coulomb wave using the linearized phase-amplitude method
Authors: Kiyokawa Shuji
Published: August 2015

The author shows that the amplitude equation from the phase-amplitude method of calculating continuum wave functions can be linearized into a 3rd-order differential equation. Using this linearized equation, in the case of the Coulomb potential, the author also shows that the amplitude function has an analytically exact solution represented by means of an irregular confluent hypergeometric function. Furthermore, it is shown that the exact solution for the Coulomb potential reproduces the wave function for free space expressed by the spherical Bessel function. The amplitude equation for the large component of the Dirac spinor is also shown to be the linearized 3rd-order differential equation.
MHD thermosolutal marangoni convection heat and mass transport of power law fluid driven by temperature and concentration gradient
Authors: Jiao Chengru , Zheng Liancun , Ma Lianxi
Published: August 2015

This paper studies the magnetohydrodynamic (MHD) thermosolutal Marangoni convection heat and mass transfer of power-law fluids driven by a power law temperature and a power law concentration which is assumed that the surface tension varies linearly with both the temperature and concentration. Heat and mass transfer constitutive equation is proposed based on N-diffusion proposed by Philip and the abnormal convection-diffusion model proposed by Pascal in which we assume that the heat diffusion depends non-linearly on both the temperature and the temperature gradient and the mass diffusion depends non-linearly on both the concentration and the concentration gradient with modified Fourier heat conduction for power law fluid. The governing equations are reduced to nonlinear ordinary differential equations by using suitable similarity transformations. Approximate analytical solution is obtained using homotopy analytical method (HAM). The transport characteristics of velocity, temperature and concentration fields are analyzed in detail.
Effect of intra-uterine growth restriction on long-term fertility in boars
Authors: Lin Yan , Cheng Xu , Sutovsky Peter , Wu De , Che Lian-Qiang , Fang Zheng-Feng , Xu Sheng-Yu , Ren Bo , Dong Hong-Jun
Published: August 2015

The present study assessed the effect of birthweight on reproductive performance, including a possible mechanism, in male pigs. Ten newborn male piglets, including five normal birthweight (NBW) piglets and five intra-uterine growth restricted (IUGR) piglets, were used in the study. All piglets were weaned on Day 28 and fed the same diet during the experiment (10 months). Average daily weight gain, feed intake and the feed conversion ratio were higher in NBW than IUGR piglets. Similarly, testis volume and the number of Leydig and Sertoli cells in the distal portion of the testes were higher in NBW than IUGR piglets (P < 0.05). Semen volume (P < 0.05) and the total number of spermatozoa per ejaculate (P = 0.08) were lower in IUGR boars. Testosterone concentrations on Day 141 and prostaglandin E2 concentrations on Days 82 and 141 were higher in IUGR than NBW boars (P < 0.05). The malondialdehyde content of seminal plasma was higher in IUGR boars, whereas sperm glutathione peroxidase activity was lower in IUGR versus NBW boars (P < 0.05). Expression of DNA methyltransferase (Dnmt) genes Dnmt1, Dnmt3a, histone-lysine N-methyltransferase (Suv39h2), and lysine (K)-specific demethylase Kdm4a was upregulated in testes from IUGR boars. These findings suggest that growth restriction affects sperm production via reproductive organ development and epigenetic regulation.
Population stability in the endangered Fleay’s barred frog (Mixophyes fleayi) and a program for long-term monitoring
Authors: Quick Gemma , Goldingay Ross L. , Parkyn Jonathan , Newell David A.
Published: August 2015

In the wake of the global decline in amphibians there is a need for long-term population monitoring. Previous research suggested that the endangered Fleay’s barred frog (Mixophyes fleayi) had recovered after a severe decline. We aimed to determine whether this recovery has been sustained and to test an example of a monitoring program that could be employed at intervals of five or more years to assess long-term population stability. We conducted capture–mark–recapture five years after the last detailed census at Brindle Creek in Border Ranges National Park, New South Wales. Frogs were captured along a 200 m creek transect between September 2013 and February 2014. We used program Mark to estimate demographic parameters of adult male frogs using two modelling approaches: robust design (RD) and the POPAN formulation of the Jolly–Seber model. Abundance was estimated at 38.2 ± 0.5 (s.e.) (RD) and 46.0 ± 2.7 (POPAN). Abundance in 2008 was estimated at 53.2 ± 10.0 (POPAN) male frogs. Estimates of apparent monthly survival over our five-month-long study were very high (RD: 1.0 ± 0.0; POPAN: 1.0 ± 0.02). Recapture estimates were also high (RD: 0.40 ± 0.07 to 0.72 ± 0.05 per session; POPAN: 0.84 ± 0.05 per month). These data suggest that the Brindle Creek population has remained relatively stable over a period of ~10 years.
Topological Bloch bands in graphene superlattices
Authors: Song Justin C. W. , Samutpraphoot Polnop , Levitov Leonid S.
Published: August 2015

Significance

A family of designer topological materials is introduced, comprising stacks of two-dimensional materials which by themselves are not topological, such as graphene. Previously, topological bands in graphene were presumed either impossible or impractical. The designer approach turns graphene into a robust platform with which a host of topological behavior can be realized and explored.
Disruption of hippocampal–prefrontal cortex activity by dopamine D2R-dependent LTD of NMDAR transmission
Authors: Banks Paul James , Burroughs Amelia Caroline , Barker Gareth Robert Isaac , Brown Jon Thomas , Warburton Elizabeth Clea , Bashir Zafar Iqbal
Published: August 2015

Significance

Synaptic transmission between the hippocampus and prefrontal cortex is required for many executive cognitive functions. It is believed that disruption of this communication contributes to symptoms observed in psychiatric disorders including schizophrenia. Hyperdopaminergic tone and hypofunction of NMDA receptor-mediated glutamate transmission are distinctive elements of schizophrenia. Here we demonstrate that activation of low-affinity D2-like dopamine receptors leads to a lasting depression of NMDA receptors at the hippocampal–prefrontal projection of juvenile rats, leading to a marked disruption of synaptic transmission. These data demonstrate a link between dopamine and hypofunction of NMDA receptor-mediated transmission with potential implications for psychiatric disease.
Propagation of prions causing synucleinopathies in cultured cells
Authors: Woerman Amanda L. , Stöhr Jan , Aoyagi Atsushi , Rampersaud Ryan , Krejciova Zuzana , Watts Joel C. , Ohyama Takao , Patel Smita , Widjaja Kartika , Oehler Abby , Sanders David W. , Diamond Marc I. , Seeley William W. , Middleton Lefkos T. , Gentleman Steve M. , Mordes Daniel A. , Südhof Thomas C. , Giles Kurt , Prusiner Stanley B.
Published: August 2015

Significance

Progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) are neurodegenerative diseases caused by tau and α-synuclein prions, respectively. Prions, purified from human brains of deceased patients with PSP and MSA using phosphotungstic acid, were applied to cultured cell models that selectively form aggregates in the presence of tau or α-synuclein prions, respectively. Whereas brain homogenates prepared from two PSP and six MSA patients infected cultured cells, the same approach was unsuccessful with brain samples from three Parkinson’s disease patients. Our findings provide compelling evidence that PSP and MSA are prion diseases, and that MSA is caused by several distinct prion strains.
Protective properties of ginsenoside Rb3 against UV-B radiation-induced oxidative stress in HaCaT keratinocytes
Authors: Oh Sun-Joo , Oh Yuri , Ryu In Wang , Kim Kyunghoon , Lim Chang-Jin
Published: August 2015

This work aimed to evaluate the skin anti-photoaging properties of ginsenoside Rb3 (Rb3), one of the main protopanaxdiol-type ginsenosides from ginseng, in HaCaT keratinocytes. The skin anti-photoaging activity was assessed by analyzing the levels of reactive oxygen species (ROS), pro-matrix metalloproteinase-2 (proMMP-2), pro-matrix metalloproteinase-9 (proMMP-9), total glutathione (GSH), and superoxide dismutase (SOD) activity as well as cell viability in HaCaT keratinocytes under UV-B irradiation. When HaCaT keratinocytes were exposed to Rb3 prior to UV-B irradiation, Rb3 exhibited suppressive activities on UV-B-induced ROS, proMMP-2, and proMMP-9 enhancements. On the contrary, Rb3 displayed enhancing activities on UV-B-reduced total GSH and SOD activity levels. Rb3 could not interfere with cell viabilities in UV-B-irradiated HaCaT keratinocytes. Rb3 plays a protective role against UV-B-induced oxidative stress in human HaCaT keratinocytes, proposing its potential skin anti-photoaging properties.
Coffee prevents proximal colorectal adenomas in Japanese men: a prospective cohort study
Authors: Nakamura Tomiyo , Ishikawa Hideki , Mutoh Michihiro , Wakabayashi Keiji , Kawano Atsuko , Sakai Toshiyuki , Matsuura Nariaki
Published: August 2015

This prospective cohort study aimed to show that coffee prevents the recurrence of colorectal tumors (adenomas, precursors of colorectal cancer, and early-stage colorectal cancers) as well as colorectal cancer. The present study included 307 patients who participated in a clinical study that required endoscopy to remove a colorectal tumor. The amount of coffee consumed by the patients at study inclusion and the frequency of colorectal tumors, as detected by colonoscopy over the subsequent 4 years, were assessed. Coffee consumption was determined using a diet survey that included 3-consecutive-day food records. The risk of colorectal tumor recurrence was significantly lower (odds ratio=0.21; 95% confidence interval, 0.06–0.74) in patients who consumed more than three cups of coffee per day compared with those who consumed no coffee. No correlation was observed between the examined factors, including green tea and black tea intake and the amount of caffeine consumed. In subanalysis divided by the tumor location within the colorectum, the odds ratio of colorectal tumor recurrence in the proximal colon showed a tendency toward reduction as coffee consumption increased; however, increased coffee consumption significantly increased colorectal tumor recurrence in the distal colon. We showed that high coffee consumption reduced the overall occurrence of colorectal tumors, affected by the reduction in the proximal colon.
Frequent users of the emergency department services in the largest academic hospital in the Netherlands: a 5-year report
Authors: Bertoli-Avella Aida M. , Haagsma Juanita A. , Van Tiel Sofie , Erasmus Vicki , Polinder Suzanne , Van Beeck Ed , Patka Peter , Rood Pleunie P.M.
Published: August 2015

Objective

To investigate the demographic and service characteristics, motive for consultation, and disposition of adult frequent users (FUs) of the largest academic hospital in the Netherlands over a 5-year period.

Patients and methods

This retrospective study included all patients aged 18 years and older visiting the emergency department (ED) during a 5-year period (2009–2013). Frequent ED use was defined as having four or more visits to the ED during a year. Patient and service characteristics, motive for consultation, and disposition were explored.

Results

Frequent ED users represented 2% of all patients who visited the ED during 2009–2013 (8% of all ED consultations). On average, each FU visited the ED five times per year. Compared with nonfrequent users (NFUs), FUs were significantly less often self-referred, less frequently transported to the hospital by ambulance, received a lower urgency code upon arrival to the ED, and more often admitted to hospital than NFUs. Complaints related to the digestive system (19%), general complaints such as fever (18%), respiratory (10%), or cardiovascular problems (10%) were the main motive for consultations of the frequent ED users. Two percent of the FUs were serial FUs (FUs during 3 or more consecutive years).

Conclusion

Frequent use of the ED has been depicted as inappropriate use of these services. However, our study shows that FUs consist of a relatively small number of patients and that FUs suffer from chronic, and often, severe somatic illnesses that require specialized medical care.
The Effectiveness of Lamotrigine and Its Blood Levels for Pediatric Epilepsy
Authors: Iwasaki Toshiyuki , Toki Taira , Nonoda Yutaka , Ishii Masahiro
Published: August 2015

This study was conducted to evaluate the effectiveness of lamotrigine (LTG) over 2 years and the usefulness of measuring its blood levels during the follow-up of patients with epilepsy. We measured peak blood LTG levels of 32 patients with epilepsy (9.16 ± 3.34 years old; mean ± SD). The blood levels were measured at 6 months, 1 year, and 2 years after reaching the LTG maintenance dosage. The effectiveness of LTG was evaluated to determine the seizure reduction rate. The patients were classified as effective cases (mean of own seizure reduction rates >50%) and ineffective cases (≤50%). The results were that the dosage and blood level showed positive correlations in the case of combination use with sodium valproate (VPA) (r = 0.690), carbamazepine and/or phenobarbital (r = 0.940), and others (r = 0.548). In several groups, the blood levels and efficacies did not show any positive correlations. In the cases of combination use with VPA, the blood levels of effective cases and ineffective cases were significantly different (P = 0.001). The optimal range was 8–11.5 μg/mL based on the average and SD values in the effective cases. No patients had any side effects. In conclusion, no precise definition of the therapeutic range was possible because of the incomplete correlation between the blood level and seizure frequency. We recommend the optimal range of LTG as a therapeutic target without any side effects, and it was established that the range in the combination with VPA was 8–11.5 μg/mL.
Wallace Leslie William Sargent. 15 February 1935 — 29 October 2012
Authors: Lynden-Bell Donald
Published: August 2015

Wallace Sargent was an astronomer who used large telescopes to great effect. He concentrated on outstanding problems concerning both the origin of the elements and the cosmological evolution of primordial gas clouds. Despite a mainly theoretical education he became an expert spectroscopist and this enabled him to demonstrate that most helium was not formed in stars but was primordial, formed in the Big Bang. This helped to determine the photon : baryon ratio that emerged from it. He played a significant part in the search for the supermassive black holes that were predicted to be in the centres of many galaxies, as is now established. He is most famous for his systematic work with Alec Boksenberg FRS on the intervening hydrogen clouds seen in absorption in the spectra of distant quasars. From their work it appears that most of the 4% of the Universe (by mass) that is now considered to be in normal atoms or ions has indeed been detected, although it is seen at considerable look-back times.
Croceifilum oryzae gen. nov., sp. nov., isolated from rice paddy soil
Authors: Hatayama Kouta , Kuno Teruaki
Published: August 2015

A mesophilic, aerobic, Gram-stain-positive, filamentous bacterial strain, designated ZYf1a3T, was isolated from rice paddy soil in Japan. This strain grew on a solid medium with formation of substrate mycelium; endospores were produced singly along the mycelium. Formation of aerial mycelium was not observed on any of the media tested. This strain produced a characteristic saffron yellow soluble pigment. Cloned 16S rRNA gene sequences of strain ZYf1a3T yielded three different copies (similarity between the three sequences: 99.8–99.9 %). One of these sequences had one base deletion. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZYf1a3T belongs to an independent phylogenetic lineage of the family Thermoactinomycetaceae. The cell wall of strain ZYf1a3T contained meso-diaminopimelic acid, alanine and glutamic acid, but no characteristic sugars. It contained menaquinone 7 as the sole menaquinone. The major cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0.The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl-N-methylethanolamine and unidentified aminophospholipids. The DNA G+C content was 42.5 mol%. From phylogenetic analysis based on 16S rRNA gene sequences and phenotypic characteristics, this strain is considered to represent a novel species in a new genus, for which the name Croceifilum oryzae gen. nov., sp. nov. is proposed. The type strain of Croceifilum oryzae is ZYf1a3T ( = JCM 30426T = CCUG 66446T = DSM 46876T).
Identification of a novel cell culture adaptation site on the capsid of foot-and-mouth disease virus
Authors: Chamberlain Kyle , Fowler Veronica L. , Barnett Paul V. , Gold Sarah , Wadsworth Jemma , Knowles Nick J. , Jackson Terry
Published: August 2015

Vaccination remains the most effective tool for control of foot-and-mouth disease both in endemic countries and as an emergency preparedness for new outbreaks. Foot-and-mouth disease vaccines are chemically inactivated virus preparations and the production of new vaccines is critically dependent upon cell culture adaptation of field viruses, which can prove problematic. A major driver of cell culture adaptation is receptor availability. Field isolates of foot-and-mouth disease virus (FMDV) use RGD-dependent integrins as receptors, whereas cell culture adaptation often selects for variants with altered receptor preferences. Previously, two independent sites on the capsid have been identified where mutations are associated with improved cell culture growth. One is a shallow depression formed by the three major structural proteins (VP1–VP3) where mutations create a heparan sulphate (HS)-binding site (the canonical HS-binding site). The other involves residues of VP1 and is located at the fivefold symmetry axis. For some viruses, changes at this site result in HS binding; for others, the receptors are unknown. Here, we report the identification of a novel site on VP2 where mutations resulted in an expanded cell tropism of a vaccine variant of A/IRN/87 (called A − ). Furthermore, we show that introducing the same mutations into a different type A field virus (A/TUR/2/2006) resulted in the same expanded cell culture tropism as the A/IRN/87 A −  vaccine variant. These observations add to the evidence for multiple cell attachment mechanisms for FMDV and may be useful for vaccine manufacture when cell culture adaptation proves difficult.