bluuebunny/crossref_metadata_2025 huggingface dataset:
Room temperature dielectric and magnetic properties of Gd and Ti co-doped BiFeO3 ceramics
Authors: Basith M. A. , Kurni O. , Alam M. S. , Sinha B. L. , Ahmmad Bashir
Published: January 2014

Room temperature dielectric and magnetic properties of BiFeO3 samples, co-doped with magnetic Gd and non-magnetic Ti in place of Bi and Fe, respectively, were reported. The nominal compositions of Bi0.9Gd0.1Fe1–xTixO3 (x = 0.00-0.25) ceramics were synthesized by conventional solid state reaction technique. X-ray diffraction patterns revealed that the substitution of Fe by Ti induces a phase transition from rhombohedral to orthorhombic at x > 0.20. Morphological studies demonstrated that the average grain size was reduced from ∼1.5 μm to ∼200 nm with the increase in Ti content. Due to Ti substitution, the dielectric constant was stable over a wide range of high frequencies (30 kHz to 20 MHz) by suppressing the dispersion at low frequencies. The dielectric properties of the compounds are associated with their improved morphologies and reduced leakage current densities probably due to the lower concentration of oxygen vacancies in the compositions. Magnetic properties of Bi0.9Gd0.1Fe1–xTixO3 (x = 0.00-0.25) ceramics measured at room temperature were enhanced with Ti substitution up to 20% compared to that of pure BiFeO3 and Ti undoped Bi0.9Gd0.1FeO3 samples. The enhanced magnetic properties might be attributed to the substitution induced suppression of spiral spin structure of BiFeO3. An asymmetric shifts both in the field and magnetization axes of magnetization versus magnetic field curves was observed. This indicates the presence of exchange bias effect in these compounds notably at room temperature.
Temperature dependence of ion-beam mixing in crystalline and amorphous germanium isotope multilayer structures
Authors: Radek M. , Bracht H. , Posselt M. , Liedke B. , Schmidt B. , Bougeard D.
Published: January 2014

Self-atom mixing induced by 310 keV gallium (Ga) ion implantation in crystalline and preamorphized germanium (Ge) at temperatures between 164 K and 623 K and a dose of 1 × 1015 cm−2 is investigated using isotopic multilayer structures of alternating 70Ge and natGe layers grown by molecular beam epitaxy. The distribution of the implanted Ga atoms and the ion-beam induced depth-dependent self-atom mixing was determined by means of secondary ion mass spectrometry. Three different temperature regimes of self-atom mixing, i.e., low-, intermediate-, and high-temperature regimes are observed. At temperatures up to 423 K, the mixing is independent of the initial structure, whereas at 523 K, the intermixing of the preamorphized Ge structure is about twice as high as that of crystalline Ge. At 623 K, the intermixing of the initially amorphous Ge structure is strongly reduced and approaches the mixing of the crystalline material. The temperature dependence of ion-beam mixing is described by competitive amorphization and recrystallization processes.
Imaginary time correlations and the phaseless auxiliary field quantum Monte Carlo
Authors: Motta M. , Galli D. E. , Moroni S. , Vitali E.
Published: January 2014

The phaseless Auxiliary Field Quantum Monte Carlo (AFQMC) method provides a well established approximation scheme for accurate calculations of ground state energies of many-fermions systems. Here we address the possibility of calculating imaginary time correlation functions with the phaseless AFQMC. We give a detailed description of the technique and test the quality of the results for static properties and imaginary time correlation functions against exact values for small systems.
Product fine-structure resolved photodissociation dynamics: The A band of H2O
Authors: Zhou Linsen , Xie Daiqian , Sun Zhigang , Guo Hua
Published: January 2014

The photodissociation dynamics of H2O in its first absorption band is investigated on an accurate potential energy surface based on a large number of high-level ab initio points. Several ro-vibrational states of the parent molecule are considered. Different from most previous theoretical studies, the spin-orbit and Λ-doublet populations of the open-shell OH fragment are reported from full-dimensional wave packet calculations. The populations of the two spin-orbit manifolds are in most cases close to the statistical limit, but the Λ-doublet is dominated by the A″ component, thanks largely to the fast in-plane dissociation of H2O($\tilde A^1 A^{\prime \prime} $Ã1A′′). Comparisons with experimental data and a Franck-Condon model are generally very good, although some discrepancies exist.
Quantum beats in conductance oscillations in graphene-based asymmetric double velocity wells and electrostatic wells
Authors: Liu Lei , Li Yu-Xian , Zhang Ying-Tao , Liu Jian-Jun
Published: January 2014

The transport properties in graphene-based asymmetric double velocity well (Fermi velocity inside the well less than that outside the well) and electrostatic well structures are investigated using the transfer matrix method. The results show that quantum beats occur in the oscillations of the conductance for asymmetric double velocity wells. The beating effect can also be found in asymmetric double electrostatic wells, but only if the widths of the two wells are different. The beat frequency for the asymmetric double well is exactly equal to the frequency difference between the oscillation rates in two isolated single wells with the same structures as the individual wells in the double well structure. A qualitative interpretation is proposed based on the fact that the resonant levels depend upon the sizes of the quantum wells. The beating behavior can provide a new way to identify the symmetry of double well structures.
Numerical simulation of shock initiation of Ni/Al multilayered composites
Authors: Sraj Ihab , Specht Paul E. , Thadhani Naresh N. , Weihs Timothy P. , Knio Omar M.
Published: January 2014

The initiation of chemical reaction in cold-rolled Ni/Al multilayered composites by shock compression is investigated numerically. A simplified approach is adopted that exploits the disparity between the reaction and shock loading timescales. The impact of shock compression is modeled using CTH simulations that yield pressure, strain, and temperature distributions within the composites due to the shock propagation. The resulting temperature distribution is then used as initial condition to simulate the evolution of the subsequent shock-induced mixing and chemical reaction. To this end, a reduced reaction model is used that expresses the local atomic mixing and heat release rates in terms of an evolution equation for a dimensionless time scale reflecting the age of the mixed layer. The computations are used to assess the effect of bilayer thickness on the reaction, as well as the impact of shock velocity and orientation with respect to the layering. Computed results indicate that initiation and evolution of the reaction are substantially affected by both the shock velocity and the bilayer thickness. In particular, at low impact velocity, Ni/Al multilayered composites with thick bilayers react completely in 100 ms while at high impact velocity and thin bilayers, reaction time was less than 100 μs. Quantitative trends for the dependence of the reaction time on the shock velocity are also determined, for different bilayer thickness and shock orientation.
Attenuation, absorption, and scattering in silver halide crystals and fibers in the mid-infrared
Authors: Israeli S. , Katzir A.
Published: January 2014

The attenuation and the absorption of silver halide crystal and fibers in the mid-IR were measured. The absorption coefficients of silver halide crystals, deformed crystals, and fibers were measured by laser calorimetry at several different wavelengths in the near-IR and the mid-IR. The absorption coefficients of the fibers were higher than those of the deformed crystals and these were higher than those of the un-deformed crystals. We suggest that the absorption behavior is best described by a weak absorption tail. The total attenuation in fibers was measured using the cut back method. The scattering values were calculated by subtracting the absorption coefficients from the total attenuation coefficients. The scattering in the silver halide fibers was ascribed to pores of estimated size of 0.7 μm. We showed that the main contribution to the attenuation of fibers in the mid-IR range was due to scattering and suggested that reducing the scattering will dramatically improve the transmission of silver halide fibers in the mid-IR.
Monte Carlo simulations of phonon transport in nanoporous silicon and germanium
Authors: Jean V. , Fumeron S. , Termentzidis K. , Tutashkonko S. , Lacroix D.
Published: January 2014

Heat conduction of nanoporous silicon and germanium thin films is studied thanks to a statistical approach. Resolution of phonon Boltzmann transport equation is performed with a Monte Carlo technique in order to assess thermal conductivity. Sensitivity of this latter property with respect to parameters such as phonon mean free path and characteristics of the pores (distribution, size, porosity) is discussed and compared to predictions from analytical models. Results point out that thermal properties might be tailored through the design of the porosity and more specifically by the adjustment of the phonon-pore mean free path. Finally, an effective medium technique is used to extend our work to multilayered crystalline-nanoporous structures. Results show that ought to pore scattering, a diffusive Fourier regime can be recovered even when the film thickness is below the bulk limit.
Revisit to phase diagram of poly(N-isopropylacrylamide) microgel suspensions by mechanical spectroscopy
Authors: Wang Huaguang , Wu Xuebang , Zhu Zhengang , Liu C. S. , Zhang Zexin
Published: January 2014

Microgels are soft particles that can be deformed and compressed, which would induce intriguing phase behaviors at high packing fractions. Poly(N-isopropylacrylamide) (PNIPAM) microgels, with a lower critical solution temperature (LCST) of 33 °C, have attracted considerable interests as model colloids, since the volume of them and the interaction between the microgels can be tuned precisely by temperature. In this work, the linear viscoelastic properties of PNIPAM microgel suspensions have been investigated using mechanical spectroscopy. A particular attention is focused on the phase behaviors at high concentrations. With increasing concentration the system undergoes a repulsive glass-to-gel transition below the LCST, while, as temperature is raised across the LCST, the system undergoes a gel-to-attractive glass transition. A mechanism of these transitions for the microgels is proposed based on the directional interaction between the particles. In moderate concentration or de-swelling microgels the interaction is isotropic leading to the glass phase, while in concentrated and deformed microgels the interaction is directional leading to the gel phase. Our results enrich the current understanding of the phase transition in microgel systems and shed new light on the phase diagram of colloidal suspensions in general.
Adjustment of threshold voltage in AlN/AlGaN/GaN high-electron mobility transistors by plasma oxidation and Al2O3 atomic layer deposition overgrowth
Authors: Gregušová D. , Jurkovič M. , Haščík Š. , Blaho M. , Seifertová A. , Fedor J. , Ťapajna M. , Fröhlich K. , Vogrinčič P. , Liday J. , Derluyn J. , Germain M. , Kuzmik J.
Published: January 2014

We discuss possibilities of adjustment of a threshold voltage VT in normally off GaN high-electron mobility transistors (HEMTs) without compromising a maximal drain current IDSmax. Techniques of a low power plasma or thermal oxidation of 2-nm thick AlN cap over 3-nm thick AlGaN barrier are developed and calibrated for a thorough oxidation of the cap with a minimal density of surface donors at the inherent oxide-semiconductor interface. It has been shown that while a thermal oxidation technique leads to the channel and/or interface degradation, low density of surface donors and scalability of VT with additionally overgrown Al2O3 may be obtained for plasma oxidized HEMTs. With 10-nm thick Al2O3 deposited at 100 °C by atomic-layer deposition, we obtained VT of 1.6 V and IDSmax of 0.48 A/mm at a gate voltage of VGS = 8 V. Density of surface donors was estimated to be about 1.2 × 1013 cm−2, leaving most of the negative polarization charge at the semiconductor surface uncompensated. Further reduction of surface donors may be needed for even higher VT.
Multiwavelength excitation Raman scattering study of polycrystalline kesterite Cu2ZnSnS4 thin films
Authors: Dimitrievska M. , Fairbrother A. , Fontané X. , Jawhari T. , Izquierdo-Roca V. , Saucedo E. , Pérez-Rodríguez A.
Published: January 2014

This work presents a complete analysis of all Raman active modes of Cu2ZnSnS4 measuring with six different excitation wavelengths from near infrared to ultraviolet. Simultaneous fitting of spectra allowed identification of 18 peaks from device grade layers with composition close to stoichiometry that are attributed to the 27 optical modes theoretically expected for this crystalline structure, including detection of 5 peaks not observed previously, but theoretically predicted. Resonance effects are assumed to explain the observed increase in intensity of weak modes for near infrared and ultraviolet excitations. These results are particularly relevant for experimental discrimination of Raman modes related to secondary phases.
Tuning the surface conditioning of trapezoidally shaped silicon nanowires by (3-aminopropyl)triethoxysilane
Authors: Duţu C. A. , Vlad A. , Reckinger N. , Flandre D. , Raskin J.-P. , Melinte S.
Published: January 2014

We report on the electrical performance of silane-treated silicon nanowires configured as n+ – p – n+ field effect transistors. The functionalization of the silicon oxide shell with (3-aminopropyl)triethoxysilane controls the formation of the conduction channel in the trapezoidal cross-section nanowires. By carefully adjusting the surface conditioning protocol, robust electrical characteristics were achieved in terms of device-to-device reproducibility for the studied silicon nanowire transistors: the standard deviation displays a fourfold decrease for the threshold voltage together with a sevenfold improvement for the subthreshold slope.
Extensions of ion orbit loss theory
Authors: Stacey W. M.
Published: January 2014

Theoretical refinements to an existing model for the loss of ions by drifting across the last closed flux surface are presented.
Ellipsometric studies of AlxGa1−xAs0.5Sb0.5 (0.0 ≤ x ≤ 0.6) alloys lattice-matched to InP(100)
Authors: Choi S. G. , Hillier G. C. , Adams J. G. J.
Published: January 2014

We report on the optical properties of AlxGa1−xAs0.5Sb0.5 (0.0 ≤ x ≤ 0.6) alloys grown by metal-organic vapor phase epitaxy on InP(100) substrates for InP-based multi-junction photovoltaic device applications. Spectroscopic ellipsometry is used to determine the complex dielectric function ε = ε1 + iε2, complex refractive index N = n + ik, normal-incidence reflectivity R, and absorption coefficients α from 0.73 to 6.45 eV at room temperature. The measured spectra exhibit four above-bandgap critical point (CP) structures E1, E1 + Δ1, E0′, and E2, and the CP energies are accurately obtained from the standard lineshape analysis. The fundamental bandgap E0 CP energies are estimated from the multilayer modeling of ellipsometric data. Dependence of the CP energies on composition x is discussed.
Study of Gd-doped Bi2Te3 thin films: Molecular beam epitaxy growth and magnetic properties
Authors: Harrison S. E. , Collins-McIntyre L. J. , Li S. , Baker A. A. , Shelford L. R. , Huo Y. , Pushp A. , Parkin S. S. P. , Harris J. S. , Arenholz E. , van der Laan G. , Hesjedal T.
Published: January 2014

Incorporation of magnetic dopants into topological insulators to break time-reversal symmetry is a prerequisite for observing the quantum anomalous Hall (QAHE) effect and other novel magnetoelectric phenomena. GdBiTe3 with a Gd:Bi ratio of 1:1 is a proposed QAHE system, however, the reported solubility limit for Gd doping into Bi2Te3 bulk crystals is between ∼0.01 and 0.05. We present a magnetic study of molecular beam epitaxy grown (GdxBi1–x)2Te3 thin films with a high Gd concentration, up to x ≈ 0.3. Magnetometry reveals that the films are paramagnetic down to 1.5 K. X-ray magnetic circular dichroism at the Gd M4,5 edge at 1.5 K reveals a saturation field of ∼6 T, and a slow decay of the magnetic moment with temperature up to 200 K. The Gd3+ ions, which are substitutional on Bi sites in the Bi2Te3 lattice, exhibit a large atomic moment of ∼7 μB, as determined by bulk-sensitive superconducting quantum interference device magnetometry. Surface oxidation and the formation of Gd2O3 lead to a reduced moment of ∼4 μB as determined by surface-sensitive x-ray magnetic circular dichroism. Their large atomic moment makes these films suitable for incorporation into heterostructures, where interface polarization effects can lead to the formation of magnetic order within the topological insulators.
Evaluation of layer-by-layer graphene structures as supercapacitor electrode materials
Authors: Zang Xiaobei , Li Peixu , Chen Qiao , Wang Kunlin , Wei Jinquan , Wu Dehai , Zhu Hongwei
Published: January 2014

Very less attention has been paid recently to the electrochemical properties of graphene films with intrinsic flat structure prepared by chemical vapor deposition (CVD). In this work, button supercapacitors were fabricated using ionic liquid as electrolytes and layer-by-layer graphene structures as electrodes. The specific capacitances of the supercapacitors increased with the increase of layer number. The areal specific capacitance of ten-layer graphene supercapacitor was 0.29 mF/cm2 at the scan rate of 50 mV/s, which was about three times of that of monolayer graphene supercapacitor (0.1 mF/cm2). The sandwiched multi-layer structures with oxide deposition further improved the device performance. However, the polycrystalline nature of CVD-grown graphene films introduced structural instability during charge-discharge process, resulting in degraded capacitive performance and cycling stability. Our results suggest that graphene films with intrinsic “in-plane” structure might not be ideal candidates for electrode materials.
Microstructural design studies for locally dissipative acoustic metamaterials
Authors: Manimala James M. , Sun C. T.
Published: January 2014

Stress wave attenuation performance of locally dissipative acoustic metamaterials with various damped oscillator microstructures is studied using mechanical lattice models. The presence of damping is represented by a complex effective mass. Analytical solutions and numerical verifications of transmissibility are obtained for Kelvin-Voigt-type (KVO), Maxwell-type, and Zener-type (ZO) oscillators with viscous damping. Although peak attenuation at resonance is diminished, dissipative microstructures can provide broad spectrum attenuation without increasing mass ratio, obviating the bandgap width limitation of locally resonant microstructures. KVO gives the best broad spectrum performance akin to a low-pass filter for excitation frequencies above a cut-off value for a prescribed transmissibility criterion. For ZO, by tailoring the damping and stiffness, the frequency range of appreciable attenuation can at least span the bandgap widths of two limiting locally resonant cases. Static and frequency-dependent measures of optimal damping that maximize the attenuation characteristics are proposed. A transitional value for the excitation frequency is identified within the locally resonant bandgap, above which there always exists an optimal amount of damping that renders the attenuation for the dissipative metamaterial greater than that for the locally resonant case. Further microstructures with hysteretic damping depict a frequency-independent scaling in the effective mass and attenuation factor, but the bandgap width remains nearly the same as that for the corresponding viscously damped microstructures. This study demonstrates that dissipative microstructures, which are to some extent unavoidable in practical designs, when tuned, provide a means to substantially enhance the attenuation bandwidth of locally resonant acoustic metamaterials while also enabling the removal of the energy sequestered by the oscillators from the system.
Dark current and light illumination effects on grating formation during periodic long-term operation in photorefractive polymers
Authors: Fujihara T. , Mamiya J. , Kawamoto M. , Sassa T.
Published: January 2014

Photorefractive grating formation dynamics in long-timescale writing and the effects of periodic writing through the control of writing beam irradiation or electric field application were investigated using typical photorefractive polymers. Both dark current and writing beam irradiation affected grating formation dynamics. Dark current in polymers changed the effective trap density over time through deep trap filling and/or detrapping and thus affected grating formation considerably. The writing beam irradiation also affected grating development in the presence of an electric field owing to the accumulation of filled deep traps. However, grating development recovered after the elimination of the electric field freed up the filled deep traps.
Scaling of the structural characteristics of nanoholes created by local droplet etching
Authors: Heyn Ch. , Schnüll S. , Hansen W.
Published: January 2014

We study the tuneability of nanoholes created by local droplet etching of AlGaAs surfaces with Al droplets at varied coverage θ of the deposited droplet material and process temperature T. For the contact angle of the as-grown droplets a mean value of 66° is determined, which depends neither on θ nor on T. The experimental results on the hole structural characteristics are interpreted in terms of scaling models yielding a general form f(θ,T)∝θqexp(E/[kBT]), with constants q and E and Boltzmann's constant kB. In detail, the hole density varies from N = 4.0 × 106 up to 1.5 × 108 cm−2, and the scaling parameters are q = 0 and E = EN = 2.46 eV. The hole diameter varies from 50 up to 190 nm with scaling parameters q = 1/3 and E = −EN/3. Moreover, the hole depth varies from 9 up to 125 nm with q = 2/3 and E = −1.73 eV. Furthermore, a threshold coverage of at least 0.2 monolayers (ML) must be deposited before hole formation takes place. In situ electron diffraction indicates that these 0.2 ML are consumed for a surface reconstruction change from (3 × 1) to (2 × 1). For coverages above 2.0 ML holes with a bimodal depth distribution are observed.
Effects of temperature and strain rate on the mechanical properties of silicene
Authors: Pei Qing-Xiang , Sha Zhen-Dong , Zhang Ying-Yan , Zhang Yong-Wei
Published: January 2014

Silicene, a graphene-like two-dimensional silicon, has attracted great attention due to its fascinating electronic properties similar to graphene and its compatibility with existing semiconducting technology. So far, the effects of temperature and strain rate on its mechanical properties remain unexplored. We investigate the mechanical properties of silicene under uniaxial tensile deformation by using molecular dynamics simulations. We find that the fracture strength and fracture strain of silicene are much higher than those of bulk silicon, though the Young's modulus of silicene is lower than that of bulk silicon. An increase in temperature decreases the fracture strength and fracture strain of silicene significantly, while an increase in strain rate enhances them slightly. The fracture process of silicene is also studied and brittle fracture behavior is observed in the simulations.
Nano-porosity in GaSb induced by swift heavy ion irradiation
Authors: Kluth P. , Sullivan J. , Li W. , Weed R. , Schnohr C. S. , Giulian R. , Araujo L. L. , Lei W. , Rodriguez M. D. , Afra B. , Bierschenk T. , Ewing R. C. , Ridgway M. C.
Published: January 2014

Nano-porous structures form in GaSb after ion irradiation with 185 MeV Au ions. The porous layer formation is governed by the dominant electronic energy loss at this energy regime. The porous layer morphology differs significantly from that previously reported for low-energy, ion-irradiated GaSb. Prior to the onset of porosity, positron annihilation lifetime spectroscopy indicates the formation of small vacancy clusters in single ion impacts, while transmission electron microscopy reveals fragmentation of the GaSb into nanocrystallites embedded in an amorphous matrix. Following this fragmentation process, macroscopic porosity forms, presumably within the amorphous phase.
Thermally stable perpendicular magnetic anisotropy features of [Co/Pd]m multilayer matrix integrated with [CoO/Pd]n bottom layer
Authors: Lee JaBin , An GwangGuk , Yang SeungMo , Chung WooSeong , Hong JinPyo
Published: January 2014

We evaluated the perpendicular magnetic anisotropy (PMA) features of a hybrid [CoO/Pd]2/[Co/Pd]7 multilayer (ML) matrix under annealing in which the [CoO/Pd]2 bottom layer was inserted. Annealing allowed for the diffusion of oxygen atoms existing in the inserted [CoO/Pd]2 layer, leading to an atomic structural reconfiguration event. The hybrid matrix was crucial to result in a higher effective anisotropy energy (3.40 Merg/cc) than an ordinary [Co/Pd]7 ML matrix (1.25 Merg/cc) under annealing at 450 °C. X-ray photoelectron spectroscopy confirmed the presence of Co-O bonding states and annealing dependent oxygen atom diffusion. The possible nature of the enhanced PMA features is discussed.
Degeneration of amyloid-ß fibrils caused by exposure to low-temperature atmospheric-pressure plasma in aqueous solution
Authors: Takai Eisuke , Ohashi Gai , Yoshida Tomonori , Margareta Sörgjerd Karin , Zako Tamotsu , Maeda Mizuo , Kitano Katsuhisa , Shiraki Kentaro
Published: January 2014

Low-temperature atmospheric-pressure plasma was applied to degenerate amyloid-ß (Aß) fibrils, which are a major component of neuritic plaque associated with Alzheimer's disease (AD). We showed that an Aß fibril exposed to a low-frequency (LF) plasma jet in aqueous solution retained its morphology, molecular weight, and cytotoxicity, but, intriguingly, decreased in protease resistance and ß-sheet content. These results suggested that an LF plasma jet could be utilized for the treatment of AD to eliminate neuritic plaque by accelerating the proteolysis of Aß fibrils.
Prediction of diet quality for sheep from faecal characteristics: comparison of near-infrared spectroscopy and conventional chemistry predictive models
Authors: Kneebone D. G. , Dryden G. McL.
Published: January 2014

This study evaluated the ability of equations developed from the analysis of faecal material by conventional chemistry (F.CHEM), and by near-infrared spectroscopy (F.NIRS), to predict intake and digestibility of forages fed with or without supplements. In vivo datasets were obtained using 30 sheep and 25 diets to provide 124 diet–faecal pairs, with each sheep fed four or five of the diets. The diets were five forages fed alone or with urea, molasses, cottonseed meal or sorghum grain supplements. Ninety-nine diet–faecal pairs were selected at random, but ensuring that all diets were represented and both the F.CHEM and F.NIRS prediction equations were developed from this dataset. The remaining 25 diet–faecal pairs were used as a validation dataset. Regressions for F.CHEM were developed by stepwise regression, and F.NIRS prediction equations were developed by partial least-squares regression. Prediction equations based solely on faecal analyte concentrations (F.CHEMc) had poor predictive ability, and models incorporating faecal constituent excretion rates (F.CHEMe) were the best at predicting feed constituent intakes. These models had slightly lower standard errors of prediction (SEP) for organic matter (OM) intake and digestible OM intake compared with the F.NIRS models that did not include faecal excretion rates. However, F.NIRS models had lower SEP for protein intake and OM digestibility. Good agreement between the F.CHEMe and F.NIRS methods was evident (according to the 95% limits-of-agreement test), and both predicted the reference values precisely and with small bias. Equations derived from a dataset that included representatives of all diets used in the experiment gave much better prediction of diet characteristics than those developed from a dataset constructed entirely at random. Equations for F.NIRS developed in this way successfully predicted the characteristics of diets that included forages fed alone and with the type of supplements used in tropical Australia.
Influence of cereal type and fat source on the performance and fat utilisation of broiler starters
Authors: Tancharoenrat P. , Ravindran V. , Ravindran G.
Published: January 2014

An experiment was conducted to determine the influence of cereal type and fat source on performance and utilisation of fat in young broiler chickens. The experimental design was a 3 × 2 factorial arrangement of treatments, which included three cereals (wheat, maize or sorghum) and two fat sources (soybean oil or tallow). Broiler starter diets, based on each cereal and supplemented with 60 g/kg of soybean oil or tallow, were fed during the 21-day experimental period. Weight gain was increased (P < 0.05) with soybean oil supplementation compared with tallow supplementation in wheat- and maize-based diets, but was unaffected (P > 0.05) by fat source in sorghum-based diets. Feed per gain was lower (P < 0.05) in birds fed soybean oil diets than those fed tallow-supplemented diets. Coefficients of total tract retention and ileal apparent digestibility of fat were higher (P < 0.05) in birds fed soybean oil diets than in those fed tallow-supplemented diets. Overall, the results suggest that the effect of fat source on weight gain of broiler starters differed depending on the cereal base used, and that soybean oil is a better fat source than tallow for young broilers.
Xylem as the main origin of stem radius changes in Eucalyptus
Authors: Zweifel Roman , Drew David M. , Schweingruber Fritz , Downes Geoffrey M.
Published: January 2014

The state-of-the-art interpretation of stem radius changes (DRTotal) for tree water relations is based on knowledge from mostly slow growing tree species. The ratio between diurnal size fluctuations of the rigid xylem (DRXylem) and the respective fluctuations of the elastic bark (DRBark) is known to be small (<0.4) and is of importance for the localisation of water storage dynamics in stems. In this study, fast growing Eucalyptus globulus Labill. in Tasmania were investigated by point dendrometers in order to investigate tree water relations. Unexpectedly, DRXylem was found to be the main driver of DRTotal with the bark acting as a passive layer on top of the fluctuating xylem under most conditions. Accordingly, the ratio between the diurnal fluctuations of the two tissues was found to be much higher (0.6–1.6) than everything reported before. Based on simulations using a hydraulic plant model, the high tissue-specific elasticity of the Eucalyptus xylem was found to explain this atypical response and not osmotically-driven processes or species-specific flow resistances. The wide zone of secondary thickening xylem in various stages of lignification is proposed to be an important component of the high wood elasticity. The tissue acts as additional water storage like the bark and may positively affect the water transport efficiency.
Effect of dietary administration of letrozole and tamoxifen on gonadal development, sex differentiation and biochemical changes in common carp (Cyprinus carpio L.)
Authors: Singh Atul K. , Srivastava P. P. , Verma Rita , Srivastava Sharad C. , Kumar Dinesh , Ansari Abubakar
Published: January 2014

The effect of letrozole and tamoxifen on the specific growth rate (SGR; % day–1), gonado–somatic index (GSI), total haemoglobin (g%), gonadal and serum protein as well as lipid, sex differentiation and 17β-oestradiol levels were studied in sexually undifferentiated Cyprinus carpio fingerlings 30 days post fertilisation (30 dpf) for 60 days. Results showed decreased GSI with tamoxifen treatment whereas letrozole increased it. There were reduced protein, lipid, triglyceride and cholesterol levels after treatment with tamoxifen and letrozole during gonadal development. Tamoxifen (200 mg kg–1 feed) induced 82.5% masculinisation, whereas letrozole in the same dose produced 98.5% males. Gonadal 17β-oestradiol significantly declined from 86.0 ± 1.41 pg per 100 mg (control) to 45.5 ± 1.94 pg per 100 mg with tamoxifen and 36.0 ± 0.72 pg per 100 mg with letrozole treatment. Similarly, serum 17β-oestradiol levels also decreased after tamoxifen and letrozole treatments. Testicular development in 37.8% of fish treated with tamoxifen and letrozole was found to be more advanced (spermatocytes) than in the control (spermatogonium); however, there was reduced ovarian growth and increased atresia. It was concluded that letrozole and tamoxifen both significantly affect sex differentiation and gonadal maturity in C. carpio leading to the production of sex-reversed males, yet the effect of letrozole was more potent.
Rapid homeostasis by disinhibition during whisker map plasticity
Authors: Li Lu , Gainey Melanie A. , Goldbeck Joseph E. , Feldman Daniel E.
Published: January 2014

Significance

Neurons exhibit distinct homeostatic and Hebbian forms of plasticity that stabilize firing rate and adaptively alter synaptic input patterns, respectively. How these mechanisms are recruited in response to sensory experience in vivo is unclear. We studied plasticity in rodent somatosensory cortex, where the neural map of the whiskers adaptively changes to reflect sensory statistics but only after a prominent initial delay. By recording synaptic excitation and inhibition in vivo, we found that the delay reflects not a lack of plasticity but a rapid homeostasis, in which inhibition is powerfully reduced to offset the initial Hebbian reduction of whisker-evoked excitation. Thus, rapid homeostasis by disinhibition stabilizes the whisker map and precedes classical whisker map plasticity.
Motor-driven marginal band coiling promotes cell shape change during platelet activation
Authors: Diagouraga Boubou , Grichine Alexei , Fertin Arnold , Wang Jin , Khochbin Saadi , Sadoul Karin
Published: January 2014

Platelets float in the blood as discoid particles. Their shape is maintained by microtubules organized in a ring structure, the so-called marginal band (MB), in the periphery of resting platelets. Platelets are activated after vessel injury and undergo a major shape change known as disc to sphere transition. It has been suggested that actomyosin tension induces the contraction of the MB to a smaller ring. In this paper, we show that antagonistic microtubule motors keep the MB in its resting state. During platelet activation, dynein slides microtubules apart, leading to MB extension rather than contraction. The MB then starts to coil, thereby inducing the spherical shape of activating platelets. Newly polymerizing microtubules within the coiled MB will then take a new path to form the smaller microtubule ring, in concerted action with actomyosin tension. These results present a new view of the platelet activation mechanism and reveal principal mechanistic features underlying cellular shape changes.
The EBI RDF platform: linked open data for the life sciences
Authors: Jupp Simon , Malone James , Bolleman Jerven , Brandizi Marco , Davies Mark , Garcia Leyla , Gaulton Anna , Gehant Sebastien , Laibe Camille , Redaschi Nicole , Wimalaratne Sarala M. , Martin Maria , Le Novère Nicolas , Parkinson Helen , Birney Ewan , Jenkinson Andrew M.
Published: January 2014

Motivation: Resource description framework (RDF) is an emerging technology for describing, publishing and linking life science data. As a major provider of bioinformatics data and services, the European Bioinformatics Institute (EBI) is committed to making data readily accessible to the community in ways that meet existing demand. The EBI RDF platform has been developed to meet an increasing demand to coordinate RDF activities across the institute and provides a new entry point to querying and exploring integrated resources available at the EBI.

Availability:  http://www.ebi.ac.uk/rdf

Contact:  jupp@ebi.ac.uk
The effectiveness of a seal scarer at a wild salmon net fishery
Authors: Harris R. N. , Harris C. M. , Duck C. D. , Boyd I. L.
Published: January 2014

During 2009 and 2010 an Acoustic Deterrent Device (ADD) was tested at a salmon bagnet. Treatment blocks when the ADD was either on or off were randomly assigned and observations were carried out from shore. During periods when the ADD was switched on, there were fewer seals observed and approximately a third more fish were landed per hour than when the ADD was switched off, these differences were both significant. Model results indicated that the higher fish landings when the ADD was operating were a direct result of the reduction in the number of seals in the vicinity of the net. Photo-identification of the seals resulted in ten grey seals and four harbour seals being identified, and showed that the majority of these were identified on one occasion, and that two grey seals made up 63% of the visits to the study area when individuals were identified. Seal-damaged fish were only found within the bagnet during off treatments. Overall, the ADD was found to be an effective seal deterrent. Refinement in the method of ADD deployment could further increase effectiveness.
p54nrb/NonO and PSF promote U snRNA nuclear export by accelerating its export complex assembly
Authors: Izumi Hiroto , McCloskey Asako , Shinmyozu Kaori , Ohno Mutsuhito
Published: January 2014

The assembly of spliceosomal U snRNPs in metazoans requires nuclear export of U snRNA precursors. Four factors, nuclear cap-binding complex (CBC), phosphorylated adaptor for RNA export (PHAX), the export receptor CRM1 and RanGTP, gather at the m7G-cap-proximal region and form the U snRNA export complex. Here we show that the multifunctional RNA-binding proteins p54nrb/NonO and PSF are U snRNA export stimulatory factors. These proteins, likely as a heterodimer, accelerate the recruitment of PHAX, and subsequently CRM1 and Ran onto the RNA substrates in vitro, which mediates efficient U snRNA export in vivo. Our results reveal a new layer of regulation for U snRNA export and, hence, spliceosomal U snRNP biogenesis.
Vortices and other topological solitons in dense quark matter
Authors: Eto Minoru , Hirono Yuji , Nitta Muneto , Yasui Shigehiro
Published: January 2014

Dense quantum chromodynamic matter accommodates various kind of topological solitons such as vortices, domain walls, monopoles, kinks, boojums, and so on. In this review, we discuss various properties of topological solitons in dense quantum chromodynamics (QCD) and their phenomenological implications. Particular emphasis is placed on the topological solitons in the color–flavor-locked (CFL) phase, which exhibits both superfluidity and superconductivity. The properties of topological solitons are discussed in terms of effective field theories such as the Ginzburg–Landau theory, the chiral Lagrangian, or the Bogoliubov–de Gennes equation. The most fundamental string-like topological excitations in the CFL phase are non-Abelian vortices, which are 1/3 quantized superfluid vortices and color magnetic flux tubes. These vortices are created at a phase transition by the Kibble–Zurek mechanism or when the CFL phase is realized in compact stars, which rotate rapidly. The interaction between vortices is found to be repulsive and consequently a vortex lattice is formed in rotating CFL matter. Bosonic and fermionic zero-energy modes are trapped in the core of a non-Abelian vortex and propagate along it as gapless excitations. The former consists of translational zero modes (a Kelvin mode) with a quadratic dispersion and ${\mathbb {C}}P^2$ Nambu–Goldstone gapless modes with a linear dispersion, associated with the CFL symmetry spontaneously broken in the core of a vortex, while the latter is Majorana fermion zero modes belonging to the triplet of the symmetry remaining in the core of a vortex. The low-energy effective theory of the bosonic zero modes is constructed as a non-relativistic free complex scalar field and a relativistic ${\mathbb {C}}P^2$ model in 1+1 dimensions. The effects of strange quark mass, electromagnetic interactions, and non-perturbative quantum corrections are taken into account in the ${\mathbb {C}}P^2$ effective theory. Various topological objects associated with non-Abelian vortices are studied; colorful boojums at the CFL interface, the quantum color magnetic monopole confined by vortices, which supports the notion of quark–hadron duality, and Yang–Mills instantons inside a non-Abelian vortex as lumps are discussed. The interactions between a non-Abelian vortex and quasiparticles such as phonons, gluons, mesons, and photons are studied. As a consequence of the interaction with photons, a vortex lattice behaves as a cosmic polarizer. As a remarkable consequence of Majorana fermion zero modes, non-Abelian vortices are shown to behave as a novel kind of non-Abelian anyon. In the order parameters of chiral symmetry breaking, we discuss fractional and integer axial domain walls, Abelian and non-Abelian axial vortices, axial wall–vortex composites, and Skyrmions.
Significance of Starch Properties and Quantity on Sponge Cake Volume
Authors: Choi Hyun‐Wook , Baik Byung‐Kee
Published: January 2014

We evaluated the qualitative and quantitative effects of wheat starch on sponge cake (SC) baking quality. Twenty wheat flours, including soft white and club wheat of normal, partial waxy, and waxy endosperm, as well as hard wheat, were tested for amylose content, pasting properties, and SC baking quality. Starches isolated from wheat flours of normal, single‐null partial waxy, double‐null partial waxy, and waxy endosperm were also tested for pasting properties and baked into SC. Double‐null partial waxy and waxy wheat flours produced SC with volume of 828–895 mL, whereas volume of SC baked from normal and single‐null partial waxy wheat flours ranged from 1,093 to 1,335 mL. The amylose content of soft white and club wheat flour was positively related to the volume of SC (r = 0.790, P < 0.001). Pasting temperature, peak viscosity, final viscosity, breakdown, and setback also showed significant relationships with SC volume. Normal and waxy starch blends having amylose contents of 25, 20, 15, and 10% produced SCs with volume of 1,570, 1,435, 1,385, and 1,185 mL, respectively. At least 70 g of starch or at least 75% starch in 100 g of starch–gluten blend in replacement of 100 g of wheat flour in the SC baking formula was needed to produce SC having the maximum volume potential. Starch properties including amylose content and pasting properties as well as proportion of starch evidently play significant roles in SC baking quality of wheat flour.
Differences in Starch Granule Composition and Structure Influence In Vitro Enzymatic Hydrolysis of Grain Meal and Extracted Starch in Two Classes of Canadian Wheat (Triticum aestivum L.)
Authors: Ahuja Geetika , Jaiswal Sarita , Hucl Pierre , Chibbar Ravindra N.
Published: January 2014

Starch granule composition and amylopectin structure affect starch digestibility, an important factor influencing wheat grain utilization for human food consumption. Six bread wheat cultivars with four belonging to the Canada Western Red Spring (CWRS) and two Canada Prairie Spring Red (CPSR) market classes were analyzed for the relationship between their grain constituents and in vitro enzymatic hydrolysis of starch. CPSR cultivars had higher starch and amylose concentrations compared with CWRS cultivars, which had a higher protein concentration. Starch granule size distribution did not differ among the genotypes, except AC Foremost, which had significantly (P < 0.05) higher volume percent of B‐type starch granules (≈15%) and lower volume percent of A‐type starch granules (≈9%) compared with other cultivars. Fluorophore‐assisted capillary electrophoresis revealed a lower content of R‐IV (DP 15–18, ≈6%) and a higher content of R‐VII (DP 37–45, ≈7%) chains in the CPSR cultivars compared with the CWRS cultivars. Starch in vitro enzymatic hydrolysis showed that compared with CWRS cultivars, the two CPSR cultivars had reduced amounts of readily digestible starch and higher amounts of slowly digestible starch and resistant starch. Consequently, the two CPSR cultivars also showed lower hydrolysis indexes in grain meal as well as extracted starch. CPSR cultivars, with higher starch and amylose concentrations, as well as a higher content of long chains of amylopectin, showed a reduced starch in vitro enzymatic hydrolysis rate.
Effects of Growing‐Up Milk Supplemented With Prebiotics and LCPUFAs on Infections in Young Children
Authors: Chatchatee Pantipa , Lee Way S. , Carrilho Eugenia , Kosuwon Pensri , Simakachorn Nipat , Yavuz Yalcin , Schouten Bastiaan , Graaff Patricia Logtens‐de , Szajewska Hania
Published: January 2014

Objective:

The aim of this study was to investigate the effect of growing‐up milk (GUM) with added short‐chain galacto‐oligosaccharides (scGOS)/long‐chain fructo‐oligosaccharides (lcFOS) (9:1) (Immunofortis) and n‐3 long‐chain polyunsaturated fatty acids (LCPUFAs) on the occurrence of infections in healthy children attending day care centres.

Methods:

In a randomised double‐blind controlled, parallel, multicountry intervention study, 767 healthy children, ages 11 to 29 months, received GUM with scGOS/lcFOS/LCPUFAs (the active group, n = 388), GUM without scGOS/lcFOS/LCPUFAs (the control group, n = 379), or cow's milk (n = 37) for 52 weeks. The primary outcome measure was the number of episodes of upper respiratory tract infections or gastrointestinal infections based on a combination of subject's illness symptoms reported by the parents during the intervention period.

Results:

Children in the active group compared with the control group had a decreased risk of developing at least 1 infection (299/388 [77%] vs 313/379 [83%], respectively, relative risk 0.93, 95% confidence interval [CI] 0.87–1.00; logistic regressionP= 0.03). There was a trend toward a reduction (P= 0.07) in the total number of infections in the active group, which was significant when confirmed by one of the investigators (268/388 [69%] vs 293/379 [77%], respectively, relative risk 0.89, 95% CI 0.82–0.97;P= 0.004, post hoc). More infectious episodes were observed in the cow's milk group, when compared with both GUM groups (34/37 [92%] vs 612/767 [80%], respectively, relative risk 1.15, 95% CI 1.04–1.28).

Conclusions:

This is the first study in children to show a reduced risk of infection following consumption of GUM supplemented with scGOS/lcFOS/n‐3 LCPUFAs. The borderline statistical significance justifies a new study to confirm this finding.