bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-functionalized iridium–Zr-MOF as a promising recyclable catalyst for the hydrogenation of aromatics
Authors: Rasero-Almansa Antonia M. , Corma Avelino , Iglesias Marta , Sánchez Félix
Published: May 2014

The multifunctional heterogeneous catalyst iridium–Zr-based MOF effectively catalyzes the hydrogenation of aromatic compounds in high yields under mild conditions.
Photocatalytic disassembly of tertiary amine-based dendrimers to monomers and their application to the ‘catch and release’ of a dye in aqueous solution
Authors: Sharma Anindra , König Burkhard , Jayaraman Narayanaswamy
Published: May 2014

Covalent bond disassembly of tertiary amine based dendrimers and their application to the ‘catch and release’ of a water-insoluble dye are reported.
Rocaglamide, silvestrol and structurally related bioactive compounds from Aglaia species
Authors: Pan Li , Woodard John L. , Lucas David M. , Fuchs James R. , Douglas Kinghorn A.
Published: May 2014

This review summarizes recent investigations on the chemistry and biology of rocaglamide, silvestrol and structurally related bioactive compounds fromAglaiaspecies published during the period 2006–2013.
Investigating peptide sequence variations for ‘double-click’ stapled p53 peptides
Authors: Lau Yu Heng , de Andrade Peterson , Sköld Niklas , McKenzie Grahame J. , Venkitaraman Ashok R. , Verma Chandra , Lane David P. , Spring David R.
Published: May 2014

Evaluating the influence of staple position, azido amino acid side-chain length and point mutation on the activity of ‘double-click’ stapled p53 peptides.
Bottom-up molecular-assembly of Ru(ii)polypyridyl complex-based hybrid nanostructures decorated with silver nanoparticles: effect of Ag nitrate concentration
Authors: Vilvamani Narayanasamy , Gupta Tarkeshwar , Gupta Rinkoo Devi , Awasthi Satish Kumar
Published: May 2014

Facile and templateless one-pot synthesis of Ru(ii)polypyridyl complex-based hybrid nanostructures decorated with silver nanoparticles (Ag NPs) with variable morphologies.
High performance of Ge@C nanocables as the anode for lithium ion batteries
Authors: Yue G. H. , Zhang X. Q. , Zhao Y. C. , Xie Q. S. , Zhang X. X. , Peng D. L.
Published: May 2014

Germanium is a promising high-capacity anode material for lithium ion batteries.
Synthesis, characterization and properties of telechelic hybrid biodegradable polymers containing polyhedral oligomeric silsesquioxane (POSS)
Authors: Fernández M. Jesús , Fernández M. Dolores , Cobos Mónica
Published: May 2014

The incorporation of POSS into PLA and PCL by click chemistry alters the thermal and surface properties of the polymers.
Z-scheme photocatalytic hydrogen production over WO3/g-C3N4 composite photocatalysts
Authors: Katsumata Hideyuki , Tachi Yusuke , Suzuki Tohru , Kaneco Satoshi
Published: May 2014

WO3/g-C3N4 catalysts exhibit excellent photocatalytic performance for H2 production from aqueous solution through the Z-scheme mechanism, which results in the efficient charge separation.
Nanoporous metal based flexible asymmetric pseudocapacitors
Authors: Hou Ying , Chen Luyang , Liu Pan , Kang Jianli , Fujita Takeshi , Chen Mingwei
Published: May 2014

Nanoporous gold dramatically enhances specific capacitances of PPy and MnO2, resulting in ultrahigh energy density and power density of the PPy–NPG//MnO2–NPG asymmetric supercapacitor with a wide potential window.
A low temperature iron molten air battery
Authors: Cui Baochen , Licht Stuart
Published: May 2014

Molten air battery, a new class of rechargeable battery with the highest storage density, is demonstrated to work at temperatures more compatible with EV applications.
Study of a magnetic-cooling material Gd(OH)CO3
Authors: Chen Yan-Cong , Qin Lei , Meng Zhao-Sha , Yang Ding-Feng , Wu Chao , Fu Zhendong , Zheng Yan-Zhen , Liu Jun-Liang , Tarasenko Róbert , Orendáč Martin , Prokleška Jan , Sechovský Vladimír , Tong Ming-Liang
Published: May 2014

The magnetocaloric effect of orthorhombic Gd(OH)CO3has been experimentally studied, which exhibits −ΔSmup to 66.4 J kg−1K−1(355 mJ cm−3K−1) for ΔH= 7 T andT= 1.8 K.
Rapid facile synthesis of Cu2ZnSnS4 nanocrystals
Authors: Chernomordik B. D. , Béland A. E. , Trejo N. D. , Gunawan A. A. , Deng D. D. , Mkhoyan K. A. , Aydil E. S.
Published: May 2014

A method for rapid synthesis of 2–40 nm diameter nanocrystal dispersions of the emerging sustainable thin-film solar absorber copper zinc tin sulfide is reported: the average crystals size is controlled by varying the synthesis temperature between 150 °C and 340 °C. Films cast from larger nanocrystals, are crack-free and suitable for making thin film solar cells.
A high performance hybrid asymmetric supercapacitor via nano-scale morphology control of graphene, conducting polymer, and carbon nanotube electrodes
Authors: Zhou Yue , Lachman Noa , Ghaffari Mehdi , Xu Haiping , Bhattacharya Dhiman , Fattahi Pouria , Abidian Mohammad Reza , Wu Shan , Gleason Karen K. , Wardle Brian L. , Zhang Q. M.
Published: May 2014

We reported a high performance hybrid asymmetric supercapacitor based on tailored electrodes.
One-step synthesis of water-dispersible silicon nanoparticles and their use in fluorescence lifetime imaging of living cells
Authors: Wang Jing , Ye Dai-Xin , Liang Guo-Hai , Chang Jian , Kong Ji-Lie , Chen Ji-Yao
Published: May 2014

Fluorescence intensity (upper panel) and lifetime (bottom panel) images of KB cells stained with FITC (B), Si NPs (C) and unstained control (A).
Cytochrome C capped mesoporous silica nanocarriers for pH-sensitive and sustained drug release
Authors: Tang Yuxia , Teng Zhaogang , Liu Ying , Tian Ying , Sun Jing , Wang Shouju , Wang Chunyan , Wang Jiandong , Lu Guangming
Published: May 2014

Drug nanocarriers with pH-sensitive and sustained drug release properties were constructed by using cytochrome C as a pore blocker to achieve high therapeutic efficacy for cancer.
An efficient light converter YAB:Cr3+,Yb3+/Nd3+ with broadband excitation and strong NIR emission for harvesting c-Si-based solar cells
Authors: Liu Pujun , Liu Jie , Zheng Xiao , Luo Hongde , Li Xiaoqing , Yao Zhiling , Yu Xibin , Shi Xiumeng , Hou Binghu , Xia Yusheng
Published: May 2014

The Cr3+–Yb3+ co-doped YAB could convert almost high-energy UV-Vis photons into low-energy NIR photons efficiently, which benefits the enhancement of silicon solar photovoltaic conversion efficiency.
Modelling of the inhibition effect of thin‐wire ultra‐corona on upward leader and its application on lightning protection in high‐voltage transmission lines
Authors: Sima Wenxia , Fan Shuochao , Yang Qing , Yuan Tao , Wang Qi
Published: May 2014

Under the induction of thundercloud charges or lightning leader, ultra‐corona occurs on the surface of thin wire‐clad conductors, which could not only inhibit the formation of streamers to prevent the development of upward leaders but also change the potential distribution in the surrounding space. Taking advantage of these characteristics, the upward leader from a power conductor can be suppressed by wrapping thin wires around ground wires. The inhibition mechanism of ultra‐corona on the upward leader has been analysed and its characteristics and development laws have been studied by constructing ultra‐corona model under thundercloud conditions. A model for studying the inhibition effect of ultra‐corona on the upward leader by combining the ultra‐corona model and leader progression model is presented, and a detailed overall analysis of its influence on lightning protection performance on a 500 kV transmission line is conducted. According to the simulation results, the shielding failure width reduces with the thin wire‐clad ground wires, and the attraction of the upward leader from power conductor on lightning leader is weakened. Therefore, the probability of lightning strikes is reduced, and lightning protection of lines is improved. Finally, two influential factors on the thin wire‐applied transmission lines are discussed.
Multi‐objective robust transmission expansion planning using information‐gap decision theory and augmented ɛ‐constraint method
Authors: Dehghan Shahab , Kazemi Ahad , Amjady Nima
Published: May 2014

This study presents a novel tractable mixed‐integer linear programming model for multiyear transmission expansion planning (TEP) problem coping with the uncertain capital costs and uncertain electricity demands using the information‐gap decision theory (IGDT). As the uncertain capital costs and electricity demands compete to occupy the permissible uncertainty budget, the proposed IGDT‐based TEP (IGDT‐TEP) framework employs the augmented ɛ‐constraint method to solve a multi‐objective optimisation problem maximising the robust regions against the uncertain variables (i.e. capital costs and electricity demands) centred on their forecasted values. This framework enables the system's planner to control the immunisation level of the optimal expansion plan regarding the enforced planning uncertainties using a certain uncertainty budget. Also, a Latin hypercube sampling‐based post‐optimisation procedure is introduced to evaluate the robustness of an expansion plan obtained from the proposed IGDT‐TEP framework. Simulation results demonstrate the effectiveness of the IGDT‐TEP model to handle the uncertain nature of capital costs and electricity demands.
Solving long time‐horizon dynamic optimal power flow of large‐scale power grids with direct solution method
Authors: Qin Zhijun , Hou Yunhe , Lu En , Luo Cheng , Cheng Shijie
Published: May 2014

Dynamic optimal power flow (DOPF) is an extension of optimal power flow for the optimal generation dispatch in a given time‐horizon. The dynamic constraints bring tremendous numerical difficulties in solving this model. With particular attention to handle dynamic constraints, an efficient method has been presented for directly solving the large‐scale DOPF Karush‐Kuhn‐Tucker (KKT) system arising from the primal–dual interior point method. First, the reduced KKT system is derived, showing that dynamic constraints lead to non‐zeros in off‐diagonal parts in the coefficient of KKT system. Then, the efficiency of the algorithm is improved by two measures: (i) to utilise the Cholesky factorisation algorithm, a constant diagonal perturbation is introduced in the positive‐indefinite KKT coefficient and (ii) efficient reordering algorithms are identified and integrated in the sparse direct solver to improve the efficiency. Case studies on the IEEE 118‐bus system over 24–96 time intervals are presented. These case studies show that the proposed method has a significant speed‐up than decomposed interior point methods. The proposed method has also been successfully applied in Chinese realistic large‐scale power grids. Two realistic case studies are reported. Both realistic cases have over 100 000 decision variables.
A new approach for magnetic curves in 3D Riemannian manifolds
Authors: Bozkurt Zehra , Gök Ismail , Yaylı Yusuf , Ekmekci F. Nejat
Published: May 2014

A magnetic field is defined by the property that its divergence is zero in a three-dimensional oriented Riemannian manifold. Each magnetic field generates a magnetic flow whose trajectories are curves called as magnetic curves. In this paper, we give a new variational approach to study the magnetic flow associated with the Killing magnetic field in a three-dimensional oriented Riemann manifold, (M3, g). And then, we investigate the trajectories of the magnetic fields called as N-magnetic and B-magnetic curves.
A regular version of Smilansky model
Authors: Barseghyan Diana , Exner Pavel
Published: May 2014

We discuss a modification of Smilansky model in which a singular potential “channel” is replaced by a regular, below unbounded potential which shrinks as it becomes deeper. We demonstrate that, similarly to the original model, such a system exhibits a spectral transition with respect to the coupling constant, and determine the critical value above which a new spectral branch opens. The result is generalized to situations with multiple potential “channels.”
Modulational instability of electromagnetic waves in a collisional quantum magnetoplasma
Authors: Niknam A. R. , Rastbood E. , Bafandeh F. , Khorashadizadeh S. M.
Published: May 2014

The modulational instability of right-hand circularly polarized electromagnetic electron cyclotron (CPEM-EC) wave in a magnetized quantum plasma is studied taking into account the collisional effects. Employing quantum hydrodynamic and nonlinear Schrödinger equations, the dispersion relation of modulated CPEM-EC wave in a collisional plasma has been derived. It is found that this wave is unstable in such a plasma system and the growth rate of the associated instability depends on various parameters such as electron Fermi temperature, plasma number density, collision frequency, and modulation wavenumber. It is shown that while the increase of collision frequency leads to increase of the growth rate of instability, especially at large wavenumber limit, the increase of plasma number density results in more stable modulated CPEM-EC wave. It is also found that in contrast to collisionless plasma in which modulational instability is restricted to small wavenumbers, in collisional plasma, the interval of instability occurrence can be extended to a large domain.
Nonlinear gyrokinetic theory based on a new method and computation of the guiding-center orbit in tokamaks
Authors: Xu Yingfeng , Dai Zongliang , Wang Shaojie
Published: May 2014

The nonlinear gyrokinetic theory in the tokamak configuration based on the two-step transform is developed; in the first step, we transform the magnetic potential perturbation to the Hamiltonian part, and in the second step, we transform away the gyroangle-dependent part of the perturbed Hamiltonian. Then the I-transform method is used to decoupled the perturbation part of the motion from the unperturbed motion. The application of the I-transform method to the computation of the guiding-center orbit and the guiding-center distribution function in tokamaks is presented. It is demonstrated that the I-transform method of the orbit computation which involves integrating only along the unperturbed orbit agrees with the conventional method which integrates along the full orbit. A numerical code based on the I-transform method is developed and two numerical examples are given to verify the new method.
Helicon plasma thruster discharge model
Authors: Lafleur T.
Published: May 2014

By considering particle, momentum, and energy balance equations, we develop a semi-empirical quasi one-dimensional analytical discharge model of radio-frequency and helicon plasma thrusters. The model, which includes both the upstream plasma source region as well as the downstream diverging magnetic nozzle region, is compared with experimental measurements and confirms current performance levels. Analysis of the discharge model identifies plasma power losses on the radial and back wall of the thruster as the major performance reduction factors. These losses serve as sinks for the input power which do not contribute to the thrust, and which reduce the maximum plasma density and hence propellant utilization. With significant radial plasma losses eliminated, the discharge model (with argon) predicts specific impulses in excess of 3000 s, propellant utilizations above 90%, and thruster efficiencies of about 30%.
Structure and dynamics of TIP3P, TIP4P, and TIP5P water near smooth and atomistic walls of different hydroaffinity
Authors: Harrach Michael F. , Drossel Barbara
Published: May 2014

We perform molecular dynamics simulations to observe the structure and dynamics of water using different water models (TIP3P, TIP4P, TIP5P) at ambient conditions, constrained by planar walls, which are either modeled by smooth potentials or regular atomic lattices, imitating the honeycomb-structure of graphene. We implement walls of different hydroaffinity, different lattice constant, and different types of interaction with the water molecules. We find that in the hydrophobic regime the smooth wall generally represents a good abstraction of the atomically rough walls, while in the hydrophilic regime there are noticeable differences in structure and dynamics between all stages of wall roughness. For a small lattice constant however the smooth and the atomically rough wall still share a number of structural and dynamical similarities. Out of the three water models, TIP5P water shows the largest degree of tetrahedral ordering and is often the one that is least perturbed by the presence of the wall.
The inherent dynamics of a molecular liquid: Geodesic pathways through the potential energy landscape of a liquid of linear molecules
Authors: Jacobson Daniel , Stratt Richard M.
Published: May 2014

Because the geodesic pathways that a liquid follows through its potential energy landscape govern its slow, diffusive motion, we suggest that these pathways are logical candidates for the title of a liquid's “inherent dynamics.” Like their namesake “inherent structures,” these objects are simply features of the system's potential energy surface and thus provide views of the system's structural evolution unobstructed by thermal kinetic energy. This paper shows how these geodesic pathways can be computed for a liquid of linear molecules, allowing us to see precisely how such molecular liquids mix rotational and translational degrees of freedom into their dynamics. The ratio of translational to rotational components of the geodesic path lengths, for example, is significantly larger than would be expected on equipartition grounds, with a value that scales with the molecular aspect ratio. These and other features of the geodesics are consistent with a picture in which molecular reorientation adiabatically follows translation—molecules largely thread their way through narrow channels available in the potential energy landscape.
Turbulent mixing of a slightly supercritical van der Waals fluid at low-Mach number
Authors: Battista F. , Picano F. , Casciola C. M.
Published: May 2014

Supercritical fluids near the critical point are characterized by liquid-like densities and gas-like transport properties. These features are purposely exploited in different contexts ranging from natural products extraction/fractionation to aerospace propulsion. Large part of studies concerns this last context, focusing on the dynamics of supercritical fluids at high Mach number where compressibility and thermodynamics strictly interact. Despite the widespread use also at low Mach number, the turbulent mixing properties of slightly supercritical fluids have still not investigated in detail in this regime. This topic is addressed here by dealing with Direct Numerical Simulations of a coaxial jet of a slightly supercritical van der Waals fluid. Since acoustic effects are irrelevant in the low Mach number conditions found in many industrial applications, the numerical model is based on a suitable low-Mach number expansion of the governing equation. According to experimental observations, the weakly supercritical regime is characterized by the formation of finger-like structures – the so-called ligaments – in the shear layers separating the two streams. The mechanism of ligament formation at vanishing Mach number is extracted from the simulations and a detailed statistical characterization is provided. Ligaments always form whenever a high density contrast occurs, independently of real or perfect gas behaviors. The difference between real and perfect gas conditions is found in the ligament small-scale structure. More intense density gradients and thinner interfaces characterize the near critical fluid in comparison with the smoother behavior of the perfect gas. A phenomenological interpretation is here provided on the basis of the real gas thermodynamics properties.
Control of critical coupling in a coiled coaxial cable resonator
Authors: Huang Jie , Wei Tao , Wang Tao , Fan Jun , Xiao Hai
Published: May 2014

This paper reports a coiled coaxial cable resonator fabricated by cutting a slot in a spring-like coiled coaxial cable to produce a periodic perturbation. Electromagnetic coupling between two neighboring slots was observed. By manipulating the number of slots, critical coupling of the coiled coaxial cable resonator can be well controlled. An ultrahigh signal-to-noise ratio (over 50 dB) at the resonant frequency band was experimentally achieved from a coiled coaxial cable resonator with 38 turns. A theoretic model is developed to understand the device physics. The proposed device can be potentially used as a high quality and flexibly designed band-stop filter or a sensor in structural health monitoring.
Characteristics of light regime on biofixation of carbon dioxide and growth of Scenedesmus obliquus with light-emitting diodes
Authors: Zhao Xin , Chai Xiaoli , Liu Guixiang , Hao Yongxia , Zhao Youcai
Published: May 2014

Light regime is one of the key factors affecting the growth and carbon dioxide fixation rate of microalgae. The results of this study demonstrated that light intensity, light duration, and light quality are significant factors to control the biomass growth and carbon dioxide fixation of Scenedesmus obliquus. The optimal light intensity for S. obliquus obtained in this study is 13 000 Lux. The maximum biomass concentration and carbon dioxide fixation rate during different light cycles were 0.992 g · l−1 and 0.326 g · L−1 · d−1 obtained under continuous illumination, respectively. The white light, resulting in higher biomass concentration than the other light, indicated that sunlight is a promising light source for the culture of microalgae. This study will provide valuable information of light regime for the cultivation of microalgae in photobioreactors.
Electromagnetic and microwave absorbing properties of SmCo coated single-wall carbon nanotubes/NiZn-ferrite nanocrystalline composite
Authors: Duan M. C. , Yu L. M. , Sheng L. M. , An K. , Ren W. , Zhao X. L.
Published: May 2014

The electromagnetism and microwave absorption properties of SmCo coated single-wall carbon nanotubes (SmCo@SWCNTs) and Ni0.5Zn0.5Fe2O4 ferrite (NiZn-ferrite) nanocrystalline composites with different ingredient weight ratios were investigated in the frequency range of 2–18 GHz. SmCo@SWCNTs were prepared by a direct current arc discharge method. NiZn-ferrite nanocrystalline was synthesized by a sol-gel method. The electromagnetic properties of the nanocomposites in the paraffin matrix were measured by a vector network analyzer. The Debye equation and Bruggeman symmetric medium equation were introduced to explain the dielectric properties of the nanocomposites, and the mechanisms for the dielectric and magnetic losses were discussed. The experiment results reveal that the absorbing properties of the nanocomposites could be improved by tuning for a suitable weight ratio between SmCo@SWCNTs and NiZn-ferrite nanocrystallines. The reflection loss simulation calculations demonstrated that the nanocomposite could be excellent materials for microwave absorption.
Plasmons in spatially separated double-layer graphene nanoribbons
Authors: Bagheri Mehran , Bahrami Mousa
Published: May 2014

Motivated by innovative progresses in designing multi-layer graphene nanostructured materials in the laboratory, we theoretically investigate the Dirac plasmon modes of a spatially separated double-layer graphene nanoribbon system, made up of a vertically offset armchair and metallic graphene nanoribbon pair. We find striking features of the collective excitations in this novel Coulomb correlated system, where both nanoribbons are supposed to be either intrinsic (undoped/ungated) or extrinsic (doped/gated). In the former, it is shown the low-energy acoustical and the high-energy optical plasmon modes are tunable only by the inter-ribbon charge separation. In the later, the aforementioned plasmon branches are modified by the added doping factor. As a result, our model could be useful to examine the existence of a linear Landau-undamped low-energy acoustical plasmon mode tuned via the inter-ribbon charge separation as well as doping. This study might also be utilized for devising novel quantum optical waveguides based on the Coulomb coupled graphene nanoribbons.
Growth of Bi2Sr2CaCu2O8+δ thin films with enhanced superconducting properties by incorporating CaIrO3 nanoparticles
Authors: De Vero J. C. , Hwang I. , Santiago A. C. L. , Chang J. , Kim J. , Sarmago R. V. , Song J. H.
Published: May 2014

We synthesized Bi2Sr2CaCu2O8+δ (Bi-2212) thin films with incorporated CaIrO3 (Ca-iridate) nanoparticles, by using pulsed laser deposition and post-growth ex situ annealing. We found that the density of incorporated Ca-iridate strongly affected the superconducting properties and microstructure of the Bi-2212 thin films. Incorporating a low density of Ca-iridate (450 laser pulses) in the Bi-2212 improved its superconducting properties (Tc-onset = 97 K, Tc-zero = 84 K) over those of pure Bi-2212 (Tc-onset = 94 K, Tc-zero = 80 K). However, incorporating a higher density (1800 pulses) significantly reduced Tc-zero to ≈ 57 K. Incorporating a low density of Ca-iridate also decreased the c-axis lattice constant. Films with incorporated Ca-iridate exhibited greater critical current density, Jc(B), than the pure Bi-2212 film. These results indicate that incorporating low densities of Ca-iridate nanoparticles into Bi-2212 can improve its superconducting properties.
Iron on GaN(0001) pseudo-1 × 1 (1+112) investigated by scanning tunneling microscopy and first-principles theory
Authors: Lin Wenzhi , Mandru Andrada-Oana , Smith Arthur R. , Takeuchi Noboru , Al-Brithen Hamad A. H.
Published: May 2014

We have investigated sub-monolayer iron deposition on atomically smooth GaN(0001) pseudo-1 × 1 (1+112). The iron is deposited at a substrate temperature of 360 °C, upon which reflection high energy electron diffraction shows a transformation to a 3×3-R30° pattern. After cooling to room temperature, the pattern transforms to a 6 × 6, and scanning tunneling microscopy reveals 6 × 6 reconstructed regions decorating the GaN step edges. First-principles theoretical calculations have been carried out for a range of possible structural models, one of the best being a Ga dimer model consisting of 2/9 monolayer of Fe incorporated into 7/3 monolayer of Ga in a relaxed but distorted structure.
Critical factor for epitaxial growth of cobalt-doped BaFe2As2 films by pulsed laser deposition
Authors: Hiramatsu Hidenori , Sato Hikaru , Katase Takayoshi , Kamiya Toshio , Hosono Hideo
Published: May 2014

We heteroepitaxially grew cobalt-doped BaFe2As2 films on (La,Sr)(Al,Ta)O3 single-crystal substrates by pulsed laser deposition using four different wavelengths and investigated how the excitation wavelength and pulse energy affected growth. Using the tilting and twisting angles of X-ray diffraction rocking curves, we quantitatively analyzed the crystallinity of each film. We found that the optimal deposition rate, which could be tuned by pulse energy, was independent of laser wavelength. The high-quality film grown at the optimal pulse energy (i.e., the optimum deposition rate) exhibited high critical current density over 1 MA/cm2 irrespective of the laser wavelength.
Polarity dependence of the electrical characteristics of Ag reflectors for high-power GaN-based light emitting diodes
Authors: Park Jae-Seong , Han Jaecheon , Ha Jun-Seok , Seong Tae-Yeon
Published: May 2014

We report on the polarity dependence of the electrical properties of Ag reflectors for high-power GaN-based light-emitting diodes. The (0001) c-plane samples become ohmic after annealing in air. However, the (11–22) semi-polar samples are non-ohmic after annealing, although the 300 °C-annealed sample shows the lowest contact resistivity. The X-ray photoemission spectroscopy (XPS) results show that the Ga 2p core level for the c-plane samples experiences larger shift toward the valence band than that for the semi-polar samples. The XPS depth profile results show that unlike the c-plane samples, the semi-polar samples contain some amounts of oxygen at the Ag/GaN interface regions. The outdiffusion of Ga atoms is far more significant in the c-plane samples than in the semi-polar samples, whereas the outdiffusion of N atoms is relatively less significant in the c-plane samples. On the basis of the electrical and XPS results, the polarity dependence of the electrical properties is described and discussed
Fast generation of domain walls with defined chirality in nanowires
Authors: Sentker Kathrin , Stein Falk-Ulrich , Bocklage Lars , Matsuyama Toru , Im Mi-Young , Fischer Peter , Meier Guido
Published: May 2014

We demonstrate the fast generation of domain walls with defined chiralities in nanowires. Nanosecond long current pulses are passed through a stripline to generate Oersted fields which create vortex domain walls in the nanowire. The direction of the Oersted field with respect to the nanowire is varied by the polarity of the voltage pulses as well by the alignment between the stripline and the nanowire. The results show that by using a tilted stripline and short current pulses domain walls with defined chirality and type can be generated.
Integrated source of tunable nonmaximally mode-entangled photons in a domain-engineered lithium niobate waveguide
Authors: Ming Yang , Wu Zi-jian , Cui Guo-xin , Tan Ai-hong , Xu Fei , Lu Yan-qing
Published: May 2014

The nonmaximally entangled state is a special kind of entangled state, which has important applications in quantum information processing. It has been generated in quantum circuits based on bulk optical elements. However, corresponding schemes in integrated quantum circuits have been rarely considered. In this Letter, we propose an effective solution for this problem. An electro-optically tunable nonmaximally mode-entangled photon state is generated in an on-chip domain-engineered lithium niobate (LN) waveguide. Spontaneous parametric down-conversion and electro-optic interaction are effectively combined through suitable domain design to transform the entangled state into our desired formation. Moreover, this is a flexible approach to entanglement architectures. Other kinds of reconfigurable entanglements are also achievable through this method. LN provides a very promising platform for future quantum circuit integration.
Synthèse rétrospective et nouvelles perspectives développementales
Authors: Bartning Inge
Published: May 2014

This chapter presents a synthesis of research on the acquisition of French as a second and foreign language undertaken at Stockholm University. It relates the earlier results of the project called InterFra (French interlanguage — development, interaction and variation) with more recent research on ultimate attainment in SLA. The study is presented in three parts. The first two are retrospective: first a description of the corpus InterFra (www.fraita.su.se/interfra) — the integral corpus is here introduced for the first time — then follow the results of the doctoral theses and the continuum of the developmental stages as proposed by Bartning and Schlyter (2004), which all build upon the InterFra corpus. The third part accounts for a recent research programme about the last stages in SLA, namely High-level proficiency in second language use, a common programme between four departments at Stockholm University. The chapter gives the latest results from studies in this programme using three learner groups near the native borderline, called ‘advanced’, ‘functional bilinguals’ and ‘near-natives’.
Pragmatic use of temporal adverbs in L1 and L2 French
Authors: Hancock Victorine
Published: May 2014

This paper deals with the functions of a number of frequent temporal adverbs and their placement in the information structure produced by highly advanced L2 speakers of French. The study concerns both structural and pragmatic aspects of learner language that seem relevant for characterizing the highly proficient French L2 user. The pragmaticalization of these adverbs, i.e. the development of different pragmatic functions in L2, is investigated. The adverbs can occupy different positions in the utterance and we expect that the pragmaticalization of the adverbs entails their syntactic isolation in the information structure. The analysis of positions showed that, for two adverbs, argumentative functions in outer positions were absent even in the most advanced speaker group.
Perception of English in relation to communication and identity
Authors: Dewi Anita
Published: May 2014

The increasing number of the so-called non-native English users has resulted in their views of English to be crucial. This qualitative study of thirty-two Indonesian lecturers, teachers, and students is aimed at revealing perceptions of English in relation to communication, culture, and national as well as religious identities. The findings reveal various perceptions of the language. Some references to Caucasians as potential interlocutors are found even though the participants believe that English has been used among ‘non-native’ speakers and that the relationship between English and the West is diminishing. The participants also view English as either not related or positively related to their national, religious, and ethnic identities. Overall, there is a demand for accentuating English in Indonesia with the local cultures.
Hong Kong university students’ perceptions of their identities in English as a Lingua Franca contexts
Authors: Sung Chit Cheung Matthew
Published: May 2014

This paper presents findings from an exploratory study that investigated the perceptions of a group of Hong Kong university students concerning their identities in English as a Lingua Franca (ELF) contexts. Qualitative data were collected primarily via in-depth interviews with a group of second-language speakers of ELF who use English with people from different first-language and cultural backgrounds on a regular basis. The analysis revealed that these participants came to terms with their identities as non-native speakers of English and emphasized the importance of maintaining their cultural identities as Hong Kong or Chinese speakers of ELF. In addition, most of them valued their ‘multicompetence’ in English, Cantonese and Putonghua when speaking English in ELF situations. The inquiry also found that some participants’ identification with other non-native speakers of English within the ELF community was rather selective and that different members within the ELF community were not perceived as equally ideal speakers of ELF. The study offers some valuable insights into the identities of ELF speakers and the wider ELF community within an Asian context.
The Vibrio cholerae toxin coregulated pilus: structure, assembly and function with implications for vaccine design.
Authors: Craig L. , Taylor R. K.
Published: May 2014

This chapter presents current understanding of Vibrio cholerae toxin coregulated pilus (TCP) with respect to its gene arrangement, subunit structure and filament architecture. It describes a theoretical mechanism by which these pili are assembled from thousands of copies of a single TcpA pilin subunit into a multifunctional helical filament that is critical for V. cholerae pathogenesis, and explains how dynamic assembly and disassembly may be intricately linked with pilus functions in microcolony formation, TcpF secretion and CTX uptake. Finally, progress towards TCP- and TcpF-based multicomponent cholera vaccines is discussed.
Type IV pili: functions and biogenesis.
Authors: Georgiadou M. , Pelicic V.
Published: May 2014

Pili (or fimbriae) are hair-like appendages that extend from the surface of many bacteria, and are polymers of primarily one protein generically named pilin. Out of the many types of pili that have been identified and classified according to their morphological and/or molecular characteristics, type IV pili (Tfp) are undoubtedly the most widespread. This chapter describes the biosynthesis, morphological, molecular characteristics, and functions of Tfp.
Pilus-based vaccine development in streptococci: variability, diversity and immunological responses.
Authors: Rinaudo D. , Moschioni M.
Published: May 2014

This chapter reviews genetic variability and molecular epidemiology data available on the pilus encoding islets of Streptococcus pneumoniae, S. agalactiae, S. pyogenes and S. suis. Immunological and preclinical protection data are also presented, if available. Finally, similarities and differences identified among the different streptococci are discussed.
Nitrogen use efficiency and optimization of nitrogen fertilization in conservation agriculture.
Authors: Grahmann K. , Verhulst N. , Buerkert A. , Ortiz-Monasterio I. , Govaerts B.
Published: May 2014

In most agroecosystems, nitrogen (N) is the most important nutrient limiting plant growth. One management strategy that affects N cycling and N use efficiency (NUE) is conservation agriculture (CA), an agricultural system based on minimum tillage, crop residue retention and crop rotation. This review summarizes the current knowledge of N management in CA and identifies research gaps that need to be addressed to optimize N management with the ultimate goal to minimize N losses into the environment and to reduce farmers' input costs. Soil physical, biological and chemical processes in CA are compared with those in conventional systems focusing on their relationship to N cycling in the soil and how they are affected by N fertilizer type, method and number of applications. Based on the little available data, CA has lower NUE rates than conventional systems, which seems largely due to N fertilizer immobilization through crop residues and increased fertilizer rates with CA. Fertilizer use recovery and NUE change with different tillage and residue management, thus the adjustment of N fertilization in CA is inevitable. Finally, the review provides a short overview of methodologies to measure NUE and its components. Available results on the optimization of NUE in CA are inconsistent and studies that cover all three components of CA are scarce. Interactions between components of CA and their effects on crop yield, grain quality, soil and fertilizer parameters are complex and will likely require site-specific management options.
Multiple social and environmental benefits of poplars and willows - Mini Review.
Authors: Richardson J. , Isebrands J. G.
Published: May 2014

Poplars and willows provide society with ecosystem services. These include direct economic benefits such as wood, fibre, fuelwood and other forest products. They also include environmental benefits improving the lives of people, such as through rehabilitation of degraded land, restoration of forest landscapes and mitigation of climate change. All of these services support rural livelihoods, enhance food security, alleviate poverty and contribute to sustainable land use and rural development, particularly in developing countries.
Metabolic adaptation during early lactation: key to cow health, longevity and a sustainable dairy production chain.
Authors: Knegsel A. T. M. van , Hammon H. M. , Bernabucci U. , Bertoni G. , Bruckmaier R. M. , Goselink R. M. A. , Gross J. J. , Kuhla B. , Metges C. C. , Parmentier H. K. , Trevisi E. , Tröscher A. , Vuuren A. M. van
Published: May 2014

Enhancing longevity by reducing involuntary culling and consequently increasing productive life and lifetime production of dairy cows is not only a strategy to improve a farm's profit, but is also related to improved animal welfare. High rates of involuntary culling in dairy cows are currently attributed to fertility problems, mastitis and locomotive disorders. Disease incidence is high in particular in the early-lactation period. The high disease incidence in early lactation has been attributed to metabolic stress related to the high metabolic priority for lactation and the inability of the cow to adapt effectively to the new lactation. Several biological mechanisms interact in the peripartum period of dairy cows and can result in this inability to adapt effectively to lactation. Biological mechanisms reviewed are metabolic adaptation, oxidative stress, immune function and inflammation, and feed intake capacity. Although relationships between these mechanisms become increasingly clear, these relationships are complex and not yet completely understood. Appropriate management of dairy cows in the peripartum period can facilitate cows to adapt to a new lactation. Nutritional and management strategies to ease adaptation are divided into strategies to restrict energy intake in the dry period, to improve energy intake in early lactation, alter repartitioning of energy between milk and body tissue, and strategies to support fat or carbohydrate metabolism. The success of various strategies, however, is often hampered by the complexity of interactions and high between-cow variation. We advocate for a multidisciplinary approach to understand and manage adaptation to a new lactation aiming at an improvement of cow welfare and longevity.
Observations of 6.7 GHz methanol masers with East-Asian VLBI Network. I. VLBI images of the first epoch of observations
Authors: Fujisawa Kenta , Sugiyama Koichiro , Motogi Kazuhito , Hachisuka Kazuya , Yonekura Yoshinori , Sawada-Satoh Satoko , Matsumoto Naoko , Sorai Kazuo , Momose Munetake , Saito Yu , Takaba Hiroshi , Ogawa Hideo , Kimura Kimihiro , Niinuma Kotaro , Hirano Daiki , Omodaka Toshihiro , Kobayashi Hideyuki , Kawaguchi Noriyuki , Shibata Katsunori M. , Honma Mareki , Hirota Tomoya , Murata Yasuhiro , Doi Akihiro , Mochizuki Nanako , Shen Zhiqiang , Chen Xi , Xia Bo , Li Bin , Kim Kee-Tae
Published: May 2014

Very-long-baseline interferometry (VLBI) monitoring of the 6.7 GHz methanol maser allows us to measure the internal proper motion of maser spots and therefore study the gas motion around high-mass young stellar objects. To this end, we have begun monitoring observations with the East-Asian VLBI Network. In this paper we present the results of the first epoch observation for 36 sources, including 35 VLBI images of the methanol maser. Since two independent sources were found in three images, images of 38 sources were obtained. In 34 sources, 10 or more spots were detected. The observed spatial scale of the maser distribution was from 9 to 4900 astronomical units, and the following morphological categories were observed: elliptical, arched, linear, paired, and complex. The position of the maser spot was determined with an accuracy of approximately 0.1 mas, which is sufficiently high to measure the internal proper motion from two years of monitoring observations. The VLBI observation, however, detected only approximately 20% of all maser emissions, suggesting that the remaining 80% of the total flux was spread into an undetectable extended distribution. Therefore, in addition to high-resolution observations, it is important to observe the whole structure of the maser emission including extended low-brightness structures, in order to reveal the associated site of the maser and gas motion.
Identification and Characterization of Suppressor Mutants of spl11-Mediated Cell Death in Rice
Authors: Shirsekar Gautam S. , Vega-Sanchez Miguel E. , Bordeos Alicia , Baraoidan Marietta , Swisshelm Andrew , Fan Jiangbo , Park Chan Ho , Leung Hei , Wang Guo-Liang
Published: May 2014

Lesion mimic mutants have been used to dissect programmed cell death (PCD) and defense-related pathways in plants. The rice lesion-mimic mutant spl11 exhibits race nonspecific resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae and the fungal pathogen Magnaporthe oryzae. Spl11 encodes an E3 ubiquitin ligase and is a negative regulator of PCD in rice. To study the regulation of Spl11-mediated PCD, we performed a genetic screen and identified three spl11 cell-death suppressor (sds) mutants. These suppressors were characterized for their resistance to X. oryzae pv. oryzae and M. oryzae and for their expression of defense-related genes. The suppression of the cell-death phenotypes was generally correlated with reduced expression of defense-related genes. When rice was challenged with avirulent isolates of M. oryzae, the disease phenotype was unaffected in the sds mutants, indicating that the suppression might be Spl11-mediated pathway specific and may only be involved in basal defense. In addition, we mapped one of the suppressor mutations to a 140-kb interval on the long arm of rice chromosome 1. Identification and characterization of these sds mutants should facilitate our efforts to elucidate the Spl11-mediated PCD pathway.
Using Caenorhabditis elegans as a Model for Obesity Pharmacology Development
Authors: Zheng Jolene , Vasselli Joseph R. , King Jason F. , King Michael L. , We Wenqian , Fitzpatrick Zachary , Johnson William D. , Finley John W. , Martin Roy J. , Keenan Michael J. , Enright Frederic M. , Greenway Frank L.
Published: May 2014

The Caenorhabditis elegans model is a rapid and inexpensive method to address pharmacologic questions. We describe the use of C. elegans to explore 2 pharmacologic questions concerning candidate antiobesity drugs and illustrate its potential usefulness in pharmacologic research: (1) to determine a ratio of betahistine–olanzapine that blocks the olanzapine-induced intestinal fat deposition (IFD) as detected by Nile red staining and (2) to identify the mechanism of action of a pharmaceutical candidate AB-101 that reduces IFD. Olanzapine (53 μg/mL) increased the IFD (12.1 ± 0.1%, P < 0.02), which was blocked by betahistine (763 μg/mL, 39.3 ± 0.01%, P < 0.05) in wild-type C. elegans (N2). AB-101 (1.0%) reduced the IFD in N2 (P < 0.05), increased the pharyngeal pumping rate (P < 0.05), and reversed the elevated IFD induced by protease inhibitors atazanavir and ritonavir (P < 0.05). AB-101 did not affect IFD in a ACS null mutant strain acs-4(ok2872) III/hT2[bli-4(e937) let-?(q782) qIs48](I;III) suggesting an involvement of the lipid oxidation pathway and an upregulation of CPT-1. Our studies suggest that C. elegans may be used as a resource in pharmacologic research. This article is intended to stimulate a greater appreciation of its value in the development of new pharmaceutical interventions.
Fecal Microbial Therapy
Authors: Merenstein Daniel , El‐Nachef Najwa , Lynch Susan V.
Published: May 2014

A rapidly expanding range of diverse human diseases is now associated with perturbations to the gastrointestinal microbiome. Fecal microbial transplant (FMT) has been used with high rates of efficacy to treat gastrointestinal microbiome perturbation associated with recurrent Clostridium difficile infection, and is now being considered for other indications. Here we discuss the gut microbiome, review published and ongoing studies using FMT as a treatment modality for human disease, consider the regulatory aspects of FMT, and outline some factors that should be considered in patients in whom this therapeutic strategy is being contemplated.
Streptococcus
moroccensis sp. nov. and Streptococcus
rifensis sp. nov., isolated from raw camel milk
Authors: Kadri Zaina , Amar Mohamed , Ouadghiri Mouna , Cnockaert Margo , Aerts Maarten , El Farricha Omar , Vandamme Peter
Published: May 2014

Two catalase- and oxidase-negative

Streptococcus

-like strains, LMG 27682T and LMG 27684T, were isolated from raw camel milk in Morocco. Comparative 16S rRNA gene sequencing assigned these bacteria to the genus
Streptococcus
with

Streptococcus rupicaprae

2777-2-07T as their closest phylogenetic neighbour (95.9 % and 95.7 % similarity, respectively). 16S rRNA gene sequence similarity between the two strains was 96.7 %. Although strains LMG 27682T and LMG 27684T shared a DNA–DNA hybridization value that corresponded to the threshold level for species delineation (68 %), the two strains could be distinguished by multiple biochemical tests, sequence analysis of the phenylalanyl-tRNA synthase (pheS), RNA polymerase (rpoA) and ATP synthase (atpA) genes and by their MALDI-TOF MS profiles. On the basis of these considerable phenotypic and genotypic differences, we propose to classify both strains as novel species of the genus
Streptococcus
, for which the names Streptococcus
moroccensis sp. nov. (type strain, LMG 27682T = CCMM B831T) and Streptococcus
rifensis sp. nov. (type strain, LMG 27684T = CCMM B833T) are proposed.