bluuebunny/crossref_metadata_2025 huggingface dataset:
Solvent-free iridium-catalyzed CO2 hydrosilylation: experiments and kinetic modeling
Authors: Jaseer E. A. , Akhtar Muhammad N. , Osman Mogahid , Al-Shammari A. , Oladipo Habeebllah B. , Garcés Karin , Fernández-Alvarez Francisco J. , Al-Khattaf Sulaiman , Oro Luis A.
Published: July 2014

Solvent-free iridium(iii)-catalyzed CO2 hydrosilylation to silylformate and kinetic modeling of such reaction are reported.
Synergetic effect of Zn substitution on the electron and phonon transport in Mg2Si0.5Sn0.5-based thermoelectric materials
Authors: Gao Hongli , Zhu Tiejun , Zhao Xinbing , Deng Yuan
Published: July 2014

Isoelectronic Zn substitution in Mg2Si0.5Sn0.5-based thermoelectric materials improved mobility without affecting carrier concentration, leading to an enhancement of ZT.
Ultrafine PEG-capped gadolinia nanoparticles: cytotoxicity and potential biomedical applications for MRI and luminescent imaging
Authors: Atabaev Timur Sh. , Lee Jong Ho , Han Dong-Wook , Kim Hyung-Kook , Hwang Yoon-Hwae
Published: July 2014

Ultrafine PEG-capped gadolinium oxide NPs doped with erbium ions, which could serve as a dual-imaging agent for MRI/optical imaging were synthesized using a simple, green, and quick method.
Enantioselective transesterification of (R,S)-2-pentanol catalyzed by a new flower-like nanobioreactor
Authors: Wu Zhuofu , Li Xiang , Li Fuguang , Yue Hong , He Chengyan , Xie Feng , Wang Zhi
Published: July 2014

The lipase-incorporated nanoflower was prepared and used for the resolution of (R,S)-2-pentanol with vinyl acetate as acyl donor inn-hexane.
Synthesis and photoswitching properties of liquid crystals derived from myo-inositol
Authors: Rahman Md Lutfor , Yusoff Mashitah Mohd , Kumar Sandeep
Published: July 2014

A new myo-inositol-based liquid crystal can be used for the creation of optical storage devices. The dark area is the UV-irradiated area forming a disordered isotropic phase, whereas the bright area protected from the light by using a mask remains in the ordered phase.
Enhanced adsorptive removal of hazardous anionic dye “congo red” by a Ni/Cu mixed-component metal–organic porous material
Authors: Hu Jue , Yu Huijing , Dai Wei , Yan Xiaoyang , Hu Xin , Huang He
Published: July 2014

Doping of Cu–BTC with a metal Ni(ii) ion plays an important role in the adsorptive removal of congo red dye.
Kinetics vs. thermodynamics: a unique crystal transformation from a uranyl peroxo-nanocluster to a nanoclustered uranyl polyborate
Authors: Zhang Yingjie , Bhadbhade Mohan , Price Jason R. , Karatchevtseva Inna , Collison David , Lumpkin Gregory R.
Published: July 2014

Kinetics vs. thermodynamics: a novel method has been developed to make a nano-clustered uranyl polyborate in aqueous solution at room temperature through a unique crystal transformation.
Copper reduction and atomic layer deposition by oxidative decomposition of formate by hydrazine
Authors: Dey Gangotri , Elliott Simon D.
Published: July 2014

We have used Density Functional Theory (DFT) to study the mechanism of three step atomic layer deposition (ALD) of copper via formate and hydrazine.
A biodegradable polymer platform for co-delivery of clinically relevant oxaliplatin and gemcitabine
Authors: Song Haiqin , Xiao Haihua , Zheng Minhua , Qi Ruogu , Yan Lesan , Jing Xiabin
Published: July 2014

Anticancer drugs of gemcitabine and oxaliplatin combined in a clinic regimen (GEMOX regimen) were co-loaded to a biodegradable polymer platform for drug delivery.
Probe spectrum measurements of Eu3+ions as a relevant tool for monitoring in vitro hydroxyapatite formation in a new borate biomaterial
Authors: Qi Shuyun , Huang Yanlin , Li Yadong , Cai Peiqing , Kim Sun Il , Seo Hyo Jin
Published: July 2014

CaB2O4powders and ceramics were prepared by the conventional solid-state reaction.
Circularly polarised array antenna with cascade feed network for broadband application in C‐band
Authors: Karamzadeh S. , Rafii V. , Kartal M. , Ucan O.N. , Virdee Bal S.
Published: July 2014

A new configuration of a circularly polarised square slot antenna (CPSSA) array operating in C‐band is presented. The array consists of 2 × 2 CPSSA elements and is fed by a novel feeding network consisting of the circuit stripline couplers and delay lines. The proposed feeding technique is applied to the 2 × 2 antenna array to increase the axial ratio (AR) bandwidth. The measured impedance bandwidth for a voltage standing wave ratio (VSWR) <2 is around 78.5% (3.4–7.8 GHz), the 3 dB AR bandwidth is about 35.7% (4.6–6.6 GHz) and the antenna has an average 14.2 dBic gain over the 3 dB AR bandwidth. The measured results corroborate well with the simulated results.
Deterministic and stochastic resilience analysis of minimum‐time‐controlled discrete‐time systems
Authors: Bonniwell J.L. , Schneider S.C. , Yaz E.E.
Published: July 2014

The resilience of discrete‐time systems subject to minimum‐time control is analysed for both deterministic and stochastic control gain perturbations. Lyapunov analysis is used to determine a tight upper bound on the control gain perturbations to maintain asymptotic stability.
Low‐profile inverted‐L aircraft antenna with one folding using ground edge current
Authors: Park Young Ju , Ham Hyoung Jun , Ryu Hong Kyun , Lee Kyu Song , Woo Jong Myung
Published: July 2014

A low‐profile inverted‐L antenna with one folding at 20−90 MHz bands for aircraft applications is presented. The designed antenna is installed on the top of the vertical stabiliser of an aircraft to increase the gain at 20 MHz using the ground edge current and to reduce air drag. The gain of the designed antenna is increased by 3 dB at 20 MHz, and the antenna length is reduced by 41% compared with the reference antenna, which is a folded monopole antenna coupled with a parasitic element. The measured 3 dB return loss bandwidth is 342.9 MHz (51.5%) and the peak gain at 200 MHz is −11.5 dBi for the 1/10 scaled sub‐model. In addition, the omnidirectional radiation pattern was observed in the operating frequency.
Normalisation of magnetic field distribution generated by circular current loop
Authors: Stevens N.
Published: July 2014

Normalised expressions for magnetic field distributions generated by a circular current loop are presented. It is demonstrated that these distributions only depend on two normalised, dimensionless parameters, with the radius of the loop as the normalisation variable. Graphical analysis of these distributions leads to a simple set of guidelines, which significantly facilitates the design of systems containing circular current loops.
Reducing oscillator PM noise from AM–PM noise correlation
Authors: Hati A. , Nelson C.W. , Howe D.A.
Published: July 2014

A new scheme for reducing the phase‐modulated (PM) noise of an oscillator from correlation between amplitude‐modulated (AM) and PM noise is presented. Experimental results of this correlation effect are also presented. An improvement of almost 10 dB in the PM noise is reported for frequency offsets with strong correlation.
New scheduling scheme for green communications in long term evolution networks
Authors: Dadashi Maleki Ainaz , Abolhassani Bahman
Published: July 2014

Green communications has been paid much attention recently, to provide energy efficient networks with a high level of quality of service (QoS). In this study, the authors propose a cross‐layer scheduling scheme for the downlink of long‐term evolution networks, considering the buffer state which may be empty in some times. Their target is to minimise energy consumption under the constraints of limited average transmitting power in the base station, and maximum tolerable delay as QoS of heterogeneous users. In the proposed scheme, the authors use an effective capacity link layer model to consider the data link layer characteristics, such as probability of non‐empty buffer and probability of maximum delay, along with the physical layer parameters. Simulation results show more than 48% reduction of energy consumption in peak traffic loads.
Low‐density parity‐check‐Feher quadrature phase shift keying signalling with frequency‐offset compensated iterative demodulation and decoding algorithm
Authors: Yang Zhihua , Li Yunhe , Li Huiyuan , Qin Jiao , Zhang Qinyu , Cao Bin
Published: July 2014

The Feher quadrature phase shift keying (FQPSK) modulation is significantly susceptible to frequency and phase offsets under low signal‐to‐noise ratios. In this study, the authors proposed a serially concatenated signalling scheme with FQPSK modulation and low‐density parity‐check coding, which could efficiently resist residual frequency offset by employing an intended compensation algorithm. The designed maximum‐likelihood estimation‐enabled compensation algorithm is incorporated into the iterative concatenated demodulation‐decoding process by using soft‐input–soft‐output‐based maximum‐a‐posteriori‐probability criterion. On the other side, the codeword sequence to be transmitted at the sender is re‐arranged in a pre‐configured order different from original codeword, in order to help the compensation algorithm diminish the impacts of frequency offsets. Simulation results show that the bit error rate of the proposed scheme can be improved efficiently up to three orders of magnitude with the frequency offsets from 100 to 700 ppm.
Preamble design for symbol synchronisation in frequency‐selective fading channels
Authors: Jabbarvaziri Faramarz , Nokhbeh‐Zaeem Mohammad , Moradi Gholamreza
Published: July 2014

In this study, a two‐step method for designing multi‐tone preambles is proposed and its performance in the frequency‐selective fading channel is optimised. The first step is to find an analytical solution for obtaining the optimum normalised tone frequencies of the multi‐tone preamble in order to perform better in frequency‐selective fading channel. To measure the quality of the preamble, the authors also propose a timing metric that provides a measure of impulsiveness of the auto‐correlation function of the preamble. The second step is to de‐normalise the tone frequencies to obtain the best performance in the presence of additive white Gaussian noise regarding a specific number of tones in a specific frequency interval. The tone frequencies are de‐normalised using a factor that maximises the impulsiveness of the auto‐correlation of the preamble. To compare the authors’ work with other methods, computer simulations are done using Monte Carlo method and the mean square error of the timing estimation is then calculated. Their work is mostly suitable for use in applications with high signal‐to‐noise ratio (SNR) such as M‐quadrature amplitude modulation high rate links because they show that their method outperforms other methods in high SNR scenarios.
Clustered‐orthogonal frequency division multiplexing for power line communication: when is it beneficial?
Authors: Ribeiro Moises V. , Colen Guilherme R. , de Campos Fabricio V.P. , Quan Zhi , Poor H. Vincent
Published: July 2014

This study presents a comprehensive analysis to highlight advantages and disadvantages, in terms of channel capacity and computational complexity (CC), of a so‐called clustered‐orthogonal frequency division multiplexing (OFDM) scheme for power line communication (PLC) technologies for access networks. By taking into account filtering, decimation and upsampling techniques, the implementations of two transmitter schemes, named (·)‐I and (·)‐II, and three receivers ones, named (·)‐I, (·)‐II and (·)‐III, that can be easily derived from the hermitian symmetric OFDM (HS‐OFDM) scheme are discussed. Numerical results show that the clustered‐OFDM schemes based on HS‐OFDM provide the same bit‐error‐rate performance as that of HS‐OFDM, double sideband‐OFDM and single sideband‐OFDM. Also, clustered‐OFDM based on the combination of (·)‐II and (·)‐III offers the lowest CC for both baseband and passband data communications. Further, it is demonstrated that the clustered‐OFDM schemes can trade off channel capacity for CC, which can give rise to low‐priced transceivers for PLC technologies. Finally, a comparative analysis of clustered‐OFDM and orthogonal frequency division multiple access (OFDMA) points out the scenarios in which clustered‐OFDM can be competitive if the complexity of the OFDM transceiver is a primary consideration.
Mechatronic method for study of random error on cable‐net reflector antennas
Authors: Zhang Shuxin , Duan Bao Yan , Chen Jianjun , Zong Yali
Published: July 2014

A mechatronic method for the study of cable‐net reflector antennas under mechanical random error is presented. In this method, the reflector mechanical random error and electrical radiation performance are taken as random variables, such that the electrical radiation performance based probability is analysed. A useful mathematical expression between the numerical characteristics of electrical radiation performance and mechanical parameters are developed. Applications on two cable‐net reflector antennas are described and the simulation results demonstrate the effectiveness of the proposed method in the random error evaluation.
Data acquisition system with pulse height capability for the TOFED time-of-flight neutron spectrometer
Authors: Chen Z. J. , Peng X. Y. , Zhang X. , Du T. F. , Hu Z. M. , Cui Z. Q. , Ge L. J. , Xie X. F. , Yuan X. , Gorini G. , Nocente M. , Tardocchi M. , Hu L. Q. , Zhong G. Q. , Lin S. Y. , Wan B. N. , Li X. Q. , Zhang G. H. , Chen J. X. , Fan T. S.
Published: July 2014

A new time-of-flight neutron spectrometer TOFED has been constructed for installation at Experimental Advanced Superconducting Tokamak. A data acquisition system combining measurements of flight time and energy from the interaction of neutrons with the TOFED scintillators has been developed. The data acquisition system can provide a digitizing resolution better than 1.5% (to be compared with the >10% resolution of the recoil particle energy in the plastic scintillators) and a time resolution <1 ns. At the same time, it is compatible with high count rate event recording, which is an essential feature to investigate phenomena occurring on time scales faster than the slowing down time (≈100 ms) of the beam ions in the plasma. Implications of these results on the TOFED capability to resolve fast ion signatures in the neutron spectrum from EAST plasmas are discussed.
Behavior of oscillatory tube flow at liquid-gas interfaces
Authors: Bauer Katrin , Bruecker Christoph
Published: July 2014

Oscillatory flow in a long tube is characterized by an annular axial velocity profile far away from the boundaries for which an analytical solution exists. The radial velocity component is zero. Near the entrance or free surface region, this analytic solution does not hold due to the boundary conditions. Herein, the flow behavior at a liquid-gas as well as liquid-wall interface is investigated in detail by means of flow visualization measurements and Particle Image Velocimetry. The results suggest an additional radial velocity component due to the influence of the boundary. An investigation of the phase locked flow depicts the generation of steady streaming below the free surface which could be identified by vortex rings. Their shape and velocities vary according to the boundary conditions. For low frequencies, the streaming patterns are similar for cases with liquid-gas and liquid-wall interface denoting that the surface tension does not play a role for these cases. The oscillatory amplitude dominates streaming strength. As the Womersley number increases the free surface becomes unstable and Faraday waves occur which are further analysed here. This instability interacts with the steady streaming patterns which causes a change in shape and increases the streaming strength.
Time-stretch microscopy based on time-wavelength sequence reconstruction from wideband incoherent source
Authors: Zhang Chi , Xu Yiqing , Wei Xiaoming , Tsia Kevin K. , Wong Kenneth K. Y.
Published: July 2014

Time-stretch microscopy has emerged as an ultrafast optical imaging concept offering the unprecedented combination of the imaging speed and sensitivity. However, dedicated wideband and coherence optical pulse source with high shot-to-shot stability has been mandated for time-wavelength mapping—the enabling process for ultrahigh speed wavelength-encoded image retrieval. From the practical point of view, exploiting methods to relax the stringent requirements (e.g., temporal stability and coherence) for the source of time-stretch microscopy is thus of great value. In this paper, we demonstrated time-stretch microscopy by reconstructing the time-wavelength mapping sequence from a wideband incoherent source. Utilizing the time-lens focusing mechanism mediated by a narrow-band pulse source, this approach allows generation of a wideband incoherent source, with the spectral efficiency enhanced by a factor of 18. As a proof-of-principle demonstration, time-stretch imaging with the scan rate as high as MHz and diffraction-limited resolution is achieved based on the wideband incoherent source. We note that the concept of time-wavelength sequence reconstruction from wideband incoherent source can also be generalized to any high-speed optical real-time measurements, where wavelength is acted as the information carrier.
Power and polarization monitor development for high power millimeter-wave
Authors: Makino R. , Kubo S. , Kobayashi K. , Kobayashi S. , Shimozuma T. , Yoshimura Y. , Igami H. , Takahashi H. , Mutoh T.
Published: July 2014

A new type monitor of power and polarization states of millimeter-waves has been developed to be installed at a miter-bend, which is a part of transmission lines of millimeter-waves, for electron cyclotron resonance heating on the Large Helical Device. The monitor measures amplitudes and phase difference of the electric field of the two orthogonal polarizations which are needed for calculation of the power and polarization states of waves. The power and phase differences of two orthogonal polarizations were successfully detected simultaneously.
Laser annealing induced ferromagnetism in SrTiO3 single crystal
Authors: Rao S. S. , Lee Y. F. , Prater J. T. , Smirnov A. I. , Narayan J.
Published: July 2014

The appearance of ferromagnetic order up to 400 K upon KrF (248 nm) laser irradiation is reported in un-doped SrTiO3 (STO) single crystal. The high resolution x-ray photo emission spectroscopy (XPS) measurements reveal a strong shift of Sr-, Ti-, and O-related peaks. X-ray diffraction of laser annealed STO does not reveal a signature of either secondary magnetic or amorphous phases. 300 K X-band (∼9.543 GHz) angle-dependent electron paramagnetic resonance (EPR) measurements showed no evidence of additional magnetic peaks upon laser irradiation. XPS and EPR data did not provide a strong evidence of Ti3+ formation upon laser annealing. No differences in the visible 300 K Raman spectra of pristine and laser annealed STO are noticed. Interestingly, the magnetic moment is decreased by almost 10-fold upon oxygen annealing of laser annealed STO, inferring that oxygen vacancies play an important role in establishing the observed ferromagnetism.
Numerical investigation of optical Tamm states in two-dimensional hybrid plasmonic-photonic crystal nanobeams
Authors: Meng Zi-Ming , Hu Yi-Hua , Ju Gui-Fang , Zhong Xiao-Lan , Ding Wei , Li Zhi-Yuan
Published: July 2014

Optical Tamm states (OTSs) in analogy with its electronic counterpart confined at the surface of crystals are optical surface modes at the interfaces between uniform metallic films and distributed Bragg reflectors. In this paper, OTSs are numerically investigated in two-dimensional hybrid plasmonic-photonic crystal nanobeams (HPPCN), which are constructed by inserting a metallic nanoparticle into a photonic crystal nanobeam formed by periodically etching square air holes into dielectric waveguides. The evidences of OTSs can be verified by transmission spectra and the field distribution at resonant frequency. Similar to OTSs in one-dimensional multilayer structures OTSs in HPPCN can be excited by both TE and TM polarization. The physical origin of OTSs in HPPCN is due to the combined contribution of strong reflection imposed by the photonic band gap (PBG) of the photonic crystal (PC) nanobeam and strong backward scattering exerted by the nanoparticle. For TE, incidence OTSs can be obtained at the frequency near the center of the photonic band gap. The transmissivity and the resonant frequency can be finely tuned by the dimension of nanoparticles. While for TM incidence OTSs are observed for relatively larger metallic nanoparticles compared with TE polarization. The differences between TE and TM polarization can be explained by two reasons. For one reason stronger backward scattering of nanoparticles for TE polarization can be achieved by the excitation of localized surface plasmon polariton of nanoparticles. This assumption has been proved by examining the scattering, absorption, and extinction cross section of the metallic nanoparticle. The other can be attributed to the deep and wide PBG available for TE polarization with less number of air holes compared with TM polarization. Our results show great promise in extending the application scope of OTSs from one-dimensional structures to practical integrated photonic devices and circuits.
Size-dependent capacitance study on InGaN-based micro-light-emitting diodes
Authors: Yang Wei , Zhang Shuailong , McKendry Jonathan J. D. , Herrnsdorf Johannes , Tian Pengfei , Gong Zheng , Ji Qingbin , Watson Ian M. , Gu Erdan , Dawson Martin D. , Feng Liefeng , Wang Cunda , Hu Xiaodong
Published: July 2014

We report a detailed study on size-dependent capacitance, especially the negative capacitance (NC), in InGaN-based micro-pixelated light-emitting diodes (μLEDs). Similar to conventional broad-area LEDs, μLEDs show NC under large forward bias. In the conventional depletion and diffusion capacitance regimes, a good linear relationship of capacitance with device size is observed. However, the NC under high forward bias shows slight deviation from above-mentioned linear relationship with device size. This behaviour can be understood if the effects of current density and junction temperature on NC are considered. The measured temperature dependence and frequency dispersion of the capacitance underpin this point of view. The NCs of two reference broad-area LEDs were also measured and compared with that of μLED clusters with the same total size. A stronger NC effect is observed in the μLED clusters, which is attributed to the increased number of sidewall defects during fabrication process.
Rarefaction wave in relativistic steady magnetohydrodynamic flows
Authors: Sapountzis Konstantinos , Vlahakis Nektarios
Published: July 2014

We construct and analyze a model of the relativistic steady-state magnetohydrodynamic rarefaction that is induced when a planar symmetric flow (with one ignorable Cartesian coordinate) propagates under a steep drop of the external pressure profile. Using the method of self-similarity, we derive a system of ordinary differential equations that describe the flow dynamics. In the specific limit of an initially homogeneous flow, we also provide analytical results and accurate scaling laws. We consider that limit as a generalization of the previous Newtonian and hydrodynamic solutions already present in the literature. The model includes magnetic field and bulk flow speed having all components, whose role is explored with a parametric study.
Direct wafer bonding technology for large-scale InGaAs-on-insulator transistors
Authors: Kim SangHyeon , Ikku Yuki , Yokoyama Masafumi , Nakane Ryosho , Li Jian , Kao Yung-Chung , Takenaka Mitsuru , Takagi Shinichi
Published: July 2014

Heterogeneous integration of III-V devices on Si wafers have been explored for realizing high device performance as well as merging electrical and photonic applications on the Si platform. Existing methodologies have unavoidable drawbacks such as inferior device quality or high cost in comparison with the current Si-based technology. In this paper, we present InGaAs-on-insulator (-OI) fabrication from an InGaAs layer grown on a Si donor wafer with a III-V buffer layer instead of growth on a InP donor wafer. This technology allows us to yield large wafer size scalability of III-V-OI layers up to the Si wafer size of 300 mm with a high film quality and low cost. The high film quality has been confirmed by Raman and photoluminescence spectra. In addition, the fabricated InGaAs-OI transistors exhibit the high electron mobility of 1700 cm2/V s and uniform distribution of the leakage current, indicating high layer quality with low defect density.
Defect induced plasticity and failure mechanism of boron nitride nanotubes under tension
Authors: Anoop Krishnan N. M. , Ghosh Debraj
Published: July 2014

The effects of Stone-Wales (SW) and vacancy defects on the failure behavior of boron nitride nanotubes (BNNTs) under tension are investigated using molecular dynamics simulations. The Tersoff-Brenner potential is used to model the atomic interaction and the temperature is maintained close to 300 K. The effect of a SW defect is studied by determining the failure strength and failure mechanism of nanotubes with different radii. In the case of a vacancy defect, the effect of an N-vacancy and a B-vacancy is studied separately. Nanotubes with different chiralities but similar diameter is considered first to evaluate the chirality dependence. The variation of failure strength with the radius is then studied by considering nanotubes of different diameters but same chirality. It is observed that the armchair BNNTs are extremely sensitive to defects, whereas the zigzag configurations are the least sensitive. In the case of pristine BNNTs, both armchair and zigzag nanotubes undergo brittle failure, whereas in the case of defective BNNTs, only the zigzag ones undergo brittle failure. An interesting defect induced plastic behavior is observed in defective armchair BNNTs. For this nanotube, the presence of a defect triggers mechanical relaxation by bond breaking along the closest zigzag helical path, with the defect as the nucleus. This mechanism results in a plastic failure.
Tuning the external optical feedback-sensitivity of a passively mode-locked quantum dot laser
Authors: Raghunathan R. , Grillot F. , Mee J. K. , Murrell D. , Kovanis V. , Lester L. F.
Published: July 2014

The external optical feedback-sensitivity of a two-section, passively mode-locked quantum dot laser operating at elevated temperature is experimentally investigated as a function of absorber bias voltage. Results show that the reverse-bias voltage on the absorber has a direct impact on the damping rate of the free-running relaxation oscillations of the optical signal output, thereby enabling interactive external control over the feedback-response of the device, even under the nearly resonant cavity configuration. The combination of high temperature operation and tunable feedback-sensitivity is highly promising from a technological standpoint, in particular, for applications requiring monolithic integration of multi-component architectures on a single chip in order to accomplish, for instance, the dual-objectives of stable pulse quality and isolation from parasitic reflections.
A new low-frequency backward mode in inhomogeneous plasmas
Authors: Vranjes J.
Published: July 2014

When an electromagnetic transverse wave propagates through an inhomogeneous plasma so that its electric field has a component in the direction of the background density gradient, there appears a disbalance of charge in every plasma layer, caused by the density gradient. Due to this, some additional longitudinal electric field component appears in the direction of the wave vector. This longitudinal field may couple with the usual electrostatic longitudinal perturbations like the ion acoustic, electron Langmuir, and ion plasma waves. As a result, these standard electrostatic waves are modified and in addition to this a completely new low-frequency mode appears. Some basic features of the coupling and modification of the ion acoustic wave, and properties of the new mode are discussed here, in ordinary electron-ion and in pair plasmas.
Nonadiabatic molecular dynamics simulation: An approach based on quantum measurement picture
Authors: Feng Wei , Xu Luting , Li Xin-Qi , Fang Weihai , Yan YiJing
Published: July 2014

Mixed-quantum-classical molecular dynamics simulation implies an effective quantum measurement on the electronic states by the classical motion of atoms. Based on this insight, we propose a quantum trajectory mean-field approach for nonadiabatic molecular dynamics simulations. The new protocol provides a natural interface between the separate quantum and classical treatments, without invoking artificial surface hopping algorithm. Moreover, it also bridges two widely adopted nonadiabatic dynamics methods, the Ehrenfest mean-field theory and the trajectory surface-hopping method. Excellent agreement with the exact results is illustrated with representative model systems, including the challenging ones for traditional methods.
Charge state control in single InAs/GaAs quantum dots by external electric and magnetic fields
Authors: Tang Jing , Cao Shuo , Gao Yunan , Sun Yue , Geng Weidong , Williams David A. , Jin Kuijuan , Xu Xiulai
Published: July 2014

We report a photoluminescence (PL) spectroscopy study of charge state control in single self-assembled InAs/GaAs quantum dots by applying electric and/or magnetic fields at 4.2 K. Neutral and charged exciton complexes were observed under applied bias voltages from −0.5 V to 0.5 V by controlling the carrier tunneling. The highly negatively charged exciton emission becomes stronger with increasing pumping power, arising from the fact that electrons have a smaller effective mass than holes and are more easily captured by the quantum dots. The integrated PL intensity of negatively charged excitons is affected significantly by a magnetic field applied along the sample growth axis. This observation is explained by a reduction in the electron drift velocity caused by an applied magnetic field, which increases the probability of non-resonantly excited electrons being trapped by localized potentials at the wetting layer interface, and results in fewer electrons distributed in the quantum dots. The hole drift velocity is also affected by the magnetic field, but it is much weaker.
Role of photonic angular momentum states in nonreciprocal diffraction from magneto-optical cylinder arrays
Authors: Guo Tian-Jing , Wu Li-Ting , Yang Mu , Guo Rui-Peng , Cui Hai-Xu , Chen Jing
Published: July 2014

Optical eigenstates in a concentrically symmetric resonator are photonic angular momentum states (PAMSs) with quantized optical orbital angular momentums (OAMs). Nonreciprocal optical phenomena can be obtained if we lift the degeneracy of PAMSs. In this article, we provide a comprehensive study of nonreciprocal optical diffraction of various orders from a magneto-optical cylinder array. We show that nonreciprocal diffraction can be obtained only for these nonzero orders. Role of PAMSs, the excitation of which is sensitive to the directions of incidence, applied magnetic field, and arrangement of the cylinders, are studied. Some interesting phenomena such as a dispersionless quasi-omnidirectional nonreciprocal diffraction and spikes associated with high-OAM PAMSs are present and discussed.
All-reflective UV-VIS-NIR transmission and fluorescence spectrometer for μm-sized samples
Authors: Kirchner Friedrich O. , Lahme Stefan , Riedle Eberhard , Baum Peter
Published: July 2014

We report on an optical transmission spectrometer optimized for tiny samples. The setup is based on all-reflective parabolic optics and delivers broadband operation from 215 to 1030 nm. A fiber-coupled light source is used for illumination and a fiber-coupled miniature spectrometer for detection. The diameter of the probed area is less than 200 μm for all wavelengths. We demonstrate the capability to record transmission, absorption, reflection, fluorescence and refractive indices of tiny and ultrathin sample flakes with this versatile device. The performance is validated with a solid state wavelength standard and with dye solutions.
Analysis of soil organic matter at the solid–water interface by nuclear magnetic resonance spectroscopy
Authors: Genest Stephanie C. , Simpson Myrna J. , Simpson André J. , Soong Ronald , McNally David J.
Published: July 2014

Environmental context
Structural and conformational information on organic matter–clay complexes and whole soils was obtained using different NMR methods. The results show that organic matter interactions with clay mineral surfaces determine the accessibility of specific organic matter components at the soil–water interface. This physical conformation may also play a role in soil biogeochemical processes and binding to pollutants in terrestrial environments.

Abstract
Organic matter (OM)–mineral interactions play an important role in OM preservation, global carbon cycling and contaminant transport. Studies have indicated that preferential sorption of OM is dependent on mineral type and solution conditions. In this study, 1H high resolution–magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was employed to examine OM chemistry in organo-clay complexes. Dissolved OM from a forest soil, Leonardite humic acid and Peat humic acid were sorbed to Ca2+ enriched kaolinite and montmorillonite. As observed using 1H HR-MAS NMR spectroscopy, kaolinite sorbed mainly long-chain aliphatic compounds such as those from plant cuticles whereas montmorillonite sorbed a mixture of aliphatic components and proteins. These results show the preferential sorption of specific dissolved OM components on clay surfaces. This was tested further using solid-state 13C and 1H HR-MAS NMR analysis of whole soils containing kaolinite and montmorillonite as well as a Peat soil for contrast. The species present at the soil–water interface were mainly aliphatic components, carbohydrates and amino acids. Aromatic constituents were present in the soils (observed by solid-state 13C NMR and by 1H HR-MAS NMR spectroscopy when a more penetrating solvent was used) which signifies that these compounds likely exist in more hydrophobic domains that are buried and surface inaccessible. This study highlights the important role of OM interactions with clay minerals in the preservation of OM in soils and suggests that OM–OM associations may also play a role in the protection of specific OM components in soil.
Genotypic differences in deep water extraction associated with drought tolerance in wheat
Authors: Ober Eric S. , Werner Peter , Flatman Edward , Angus William J. , Jack Peter , Smith-Reeve Lucy , Tapsell Chris
Published: July 2014

The ability of roots to extract soil moisture is critical for maintaining yields during drought. However, the extent of genotypic variation for rooting depth and drought tolerance in Northern European wheat (Triticum aestivum L.) germplasm is not known. The objectives of this study were to measure genotypic differences in root activity, test relationships between water use and yield, examine trade-offs between yield potential and investment of biomass in deep roots, and identify genotypes that contrast in deep root activity. A diverse set of 21 wheat genotypes was evaluated under irrigated and managed drought conditions in the field. Root activity was inferred from patterns of water extraction from the soil profile. Genotypes were equally capable of exploiting soil moisture in the upper layers, but there were significant genotypic differences in rates of water uptake after anthesis in deeper soil layers. For example, across the three years of the study, the variety Xi19 showed consistently deeper root activity than the variety Spark; Xi19 also showed greater drought tolerance than Spark. There were positive correlations between water extraction from depth and droughted yields and drought tolerance, but correlations between deep water use and yield potential were not significant or only weakly negative. With appropriate screening tools, selection for genotypes that can better mine deep soil water should improve yield stability in variable rainfall environments.
p53Ψ is a transcriptionally inactive p53 isoform able to reprogram cells toward a metastatic-like state
Authors: Senturk Serif , Yao Zhan , Camiolo Matthew , Stiles Brendon , Rathod Trushar , Walsh Alice M. , Nemajerova Alice , Lazzara Matthew J. , Altorki Nasser K. , Krainer Adrian , Moll Ute M. , Lowe Scott W. , Cartegni Luca , Sordella Raffaella
Published: July 2014

Significance

p53 is one of the most intensively studied tumor-suppressor genes. We identified a naturally occurring p53 isoform, generated by an alternative-splicing event, that, although lacking transcriptional activity and canonical tumor suppressor functions, is able to reprogram cells toward the acquisition of metastatic features via a cyclophilin D interaction in the mitochondria matrix. Interestingly, this isoform is expressed on tissue injury and in tumors characterized by increased metastatic spread. In some of these tumors, p53-like isoforms are generated by intron 6 mutations. This suggests a possible physiological origin of certain p53 mutations and indicates that mutations resulting in the generation of truncated p53Ψ-like proteins do more than create a 53-null state.
Efficient plant male fertility depends on vegetative nuclear movement mediated by two families of plant outer nuclear membrane proteins
Authors: Zhou Xiao , Meier Iris
Published: July 2014

Significance

Double fertilization of the female gametophyte is vital for angiosperm reproduction and requires delivery of sperm cells through a pollen tube. The sperm cells and pollen vegetative nucleus together are called the male germ unit. The pollen tube grows a long distance from the stigma to the ovary, and the mode of male germ unit movement and sperm cell delivery is largely unknown. This study reveals that WPP domain-interacting protein, a plant analog of animal proteins known to control nuclear movement, and WPP domain-interacting tail-anchored protein are responsible for movement of the vegetative nucleus within pollen tubes and contribute to sperm cell-to-ovule migration. This finding marks a leap forward in our understanding of double fertilization and the mechanism of nuclear movement in plants as a whole.
Zinc transporter SLC39A10/ZIP10 facilitates antiapoptotic signaling during early B-cell development
Authors: Miyai Tomohiro , Hojyo Shintaro , Ikawa Tomokatsu , Kawamura Masami , Irié Tarou , Ogura Hideki , Hijikata Atsushi , Bin Bum-Ho , Yasuda Takuwa , Kitamura Hiroshi , Nakayama Manabu , Ohara Osamu , Yoshida Hisahiro , Koseki Haruhiko , Mishima Kenji , Fukada Toshiyuki
Published: July 2014

Significance

Zinc deficiency is known to trigger lymphopenia, but the mechanisms behind zinc-mediated lymphocyte maintenance have been unclear. We demonstrated that zinc uptake into cells through the zinc transporter ZIP10 is essential for cell survival in early B-cell development. The ablation of ZIP10 caused an increase in caspase activity accompanied by reduced intracellular zinc in the early B-cell developmental stages. The JAK-STAT pathways regulated ZIP10 expression, and ZIP10 expression was correlated with STAT activation in B-cell lymphoma samples. Our results establish a physiological role for ZIP10 in early B-cell survival.
Zinc transporter SLC39A10/ZIP10 controls humoral immunity by modulating B-cell receptor signal strength
Authors: Hojyo Shintaro , Miyai Tomohiro , Fujishiro Hitomi , Kawamura Masami , Yasuda Takuwa , Hijikata Atsushi , Bin Bum-Ho , Irié Tarou , Tanaka Junichi , Atsumi Toru , Murakami Masaaki , Nakayama Manabu , Ohara Osamu , Himeno Seiichiro , Yoshida Hisahiro , Koseki Haruhiko , Ikawa Tomokatsu , Mishima Kenji , Fukada Toshiyuki
Published: July 2014

Significance

The essential micronutrient zinc is known to modulate adaptive immune responses and dysregulated zinc homeostasis leads to immunodeficiency. However, the molecular mechanisms underlying this zinc-mediated modulation are unknown. We show that the zinc transporter ZIP10 plays an important role in B-cell receptor (BCR) signaling.Zip10-deficiency in mature B cells attenuated both T-cell–dependent and –independent immune responses.Zip10-deficient mature B cells proliferated poorly in response to BCR cross-linking, as a result of dysregulated BCR signaling. Our data establish that ZIP10 functions as a cellular regulator to modulate BCR signaling in humoral immune responses.
Structural and thermodynamic consequences of burial of an artificial ion pair in the hydrophobic interior of a protein
Authors: Robinson Aaron C. , Castañeda Carlos A. , Schlessman Jamie L. , García-Moreno E. Bertrand
Published: July 2014

Significance

Charges buried in hydrophobic environments in proteins play essential roles in energy transduction. We engineered an artificial ion pair in the hydrophobic core of a protein to demonstrate that buried ion pairs can be charged and stabilized, in this instance, by a strong Coulomb interaction worth 5 kcal/mol. Despite this interaction, the buried charge pair destabilized the folded protein because the Coulomb interaction recovered the energetic penalty for dehydrating only one of the two buried charges. Our results suggest how artificial active sites can be engineered in stable proteins without the need to design or evolve specialized structural adaptations to stabilize the buried charges. Minor structural reorganization is sufficient to mitigate the deleterious consequences of charges buried in hydrophobic environments.
BitPAl: a bit-parallel, general integer-scoring sequence alignment algorithm
Authors: Loving Joshua , Hernandez Yozen , Benson Gary
Published: July 2014

Motivation: Mapping of high-throughput sequencing data and other bulk sequence comparison applications have motivated a search for high-efficiency sequence alignment algorithms. The bit-parallel approach represents individual cells in an alignment scoring matrix as bits in computer words and emulates the calculation of scores by a series of logic operations composed of AND, OR, XOR, complement, shift and addition. Bit-parallelism has been successfully applied to the longest common subsequence (LCS) and edit-distance problems, producing fast algorithms in practice.

Results: We have developed BitPAl, a bit-parallel algorithm for general, integer-scoring global alignment. Integer-scoring schemes assign integer weights for match, mismatch and insertion/deletion. The BitPAl method uses structural properties in the relationship between adjacent scores in the scoring matrix to construct classes of efficient algorithms, each designed for a particular set of weights. In timed tests, we show that BitPAl runs 7–25 times faster than a standard iterative algorithm.

Availability and implementation: Source code is freely available for download at http://lobstah.bu.edu/BitPAl/BitPAl.html . BitPAl is implemented in C and runs on all major operating systems.

Contact : jloving@bu.edu or yhernand@bu.edu or gbenson@bu.edu

Supplementary information : Supplementary data are available at Bioinformatics online.
Identification of discrete classes of small nucleolar RNA featuring different ends and RNA binding protein dependency
Authors: Deschamps-Francoeur Gabrielle , Garneau Daniel , Dupuis-Sandoval Fabien , Roy Audrey , Frappier Marie , Catala Mathieu , Couture Sonia , Barbe-Marcoux Mélissa , Abou-Elela Sherif , Scott Michelle S.
Published: July 2014

Small nucleolar RNAs (snoRNAs) are among the first discovered and most extensively studied group of small non-coding RNA. However, most studies focused on a small subset of snoRNAs that guide the modification of ribosomal RNA. In this study, we annotated the expression pattern of all box C/D snoRNAs in normal and cancer cell lines independent of their functions. The results indicate that C/D snoRNAs are expressed as two distinct forms differing in their ends with respect to boxes C and D and in their terminal stem length. Both forms are overexpressed in cancer cell lines but display a conserved end distribution. Surprisingly, the long forms are more dependent than the short forms on the expression of the core snoRNP protein NOP58, thought to be essential for C/D snoRNA production. In contrast, a subset of short forms are dependent on the splicing factor RBFOX2. Analysis of the potential secondary structure of both forms indicates that the k-turn motif required for binding of NOP58 is less stable in short forms which are thus less likely to mature into a canonical snoRNP. Taken together the data suggest that C/D snoRNAs are divided into at least two groups with distinct maturation and functional preferences.
Origin of the European avian-like swine influenza viruses
Authors: Krumbholz Andi , Lange Jeannette , Sauerbrei Andreas , Groth Marco , Platzer Matthias , Kanrai Pumaree , Pleschka Stephan , Scholtissek Christoph , Büttner Mathias , Dürrwald Ralf , Zell Roland
Published: July 2014

The avian-like swine influenza viruses emerged in 1979 in Belgium and Germany. Thereafter, they spread through many European swine-producing countries, replaced the circulating classical swine H1N1 influenza viruses, and became endemic. Serological and subsequent molecular data indicated an avian source, but details remained obscure due to a lack of relevant avian influenza virus sequence data. Here, the origin of the European avian-like swine influenza viruses was analysed using a collection of 16 European swine H1N1 influenza viruses sampled in 1979–1981 in Germany, the Netherlands, Belgium, Italy and France, as well as several contemporaneous avian influenza viruses of various serotypes. The phylogenetic trees suggested a triple reassortant with a unique genotype constellation. Time-resolved maximum clade credibility trees indicated times to the most recent common ancestors of 34–46 years (before 2008) depending on the RNA segment and the method of tree inference.
ResistanceGA: An R package for the optimization of resistance surfaces using genetic algorithms
Authors: Peterman William E.
Published: July 2014

Understanding how landscape features affect functional connectivity among populations is a cornerstone of landscape genetic analyses. However, parameterization of resistance surfaces that best describe connectivity is largely a subjective process that explores a limited parameter space.

ResistanceGAis a newRpackage that utilizes a genetic algorithm to optimize resistance surfaces based on pairwise genetic distances and either CIRCUITSCAPE resistance distances or cost distances calculated along least cost paths. Functions in this package allow for the optimization of both categorical and continuous resistance surfaces, as well as the simultaneous optimization of multiple resistance surfaces.

There is considerable controversy concerning the use of Mantel tests to accurately relate pairwise genetic distances with resistance distances. Optimization in uses linear mixed effects models with the maximum likelihood population effects parameterization to determine AICc, which is the fitness function for the genetic algorithm.

ResistanceGAfills a void in the landscape genetic toolbox, allowing for unbiased optimization of resistance surfaces and for the simultaneous optimization of multiple resistance surfaces to create a novel composite resistance surface.