bluuebunny/crossref_metadata_2025 huggingface dataset:
Lysosome-specific one-photon fluorescence staining and two-photon singlet oxygen generation by molecular dyad
Authors: Cho Somin , You Youngmin , Nam Wonwoo
Published: March 2014

A dual functional molecular dyad, consisting of a cyclometalated Ir(iii) complex and rhodamine B, has been synthesized and evaluated for its ability for independent operations of fluorescence staining and photodynamic therapy.
Magnetic control of flexoelectric domains in a nematic fluid
Authors: Salamon Péter , Éber Nándor , Buka Ágnes , Ostapenko Tanya , Dölle Sarah , Stannarius Ralf
Published: March 2014

Flexoelectric patterns were studied under the influence of magnetic fields applied in different geometries in a nematic fluid.
Rational design of graphene/porous carbon aerogels for high-performance flexible all-solid-state supercapacitors
Authors: Ju Hong-Fei , Song Wei-Li , Fan Li-Zhen
Published: March 2014

Graphene/porous carbon aerogels were rationally designed by a simple green process, exhibiting excellent electrochemical performance and long-term cycle stability as the electrode materials in flexible all-solid-state supercapacitors.
Selective lithium extraction from brines by chemical reaction with battery materials
Authors: Intaranont Noramon , Garcia-Araez Nuria , Hector Andrew L. , Milton J. Andy , Owen John R.
Published: March 2014

We demonstrate fast and efficient chemical redox insertion of lithium ions into solid FePO4 from lithium salt solutions contaminated with other cations.
Interaction of substituted poly(phenyleneethynylene)s with ligand-stabilized CdS nanoparticles
Authors: Liu Hua , Espe Matthew , Modarelli David A. , Arias Eduardo , Moggio Ivana , Ziolo Ronald F. , Heinz Hendrik
Published: March 2014

The interfacial region of surface-modified semiconducting nanoparticles and polymers contributes to the limited efficiency of hybrid photovoltaic cells and has been analyzed by molecular simulation at atomic resolution to complement experimental measurements.
A novel nanoassembled doxorubicin prodrug with a high drug loading for anticancer drug delivery
Authors: Xu Zhigang , Zhang Kelin , Hou Cuilan , Wang Dongdong , Liu Xiaoyan , Guan Xiujuan , Zhang Xiaoyu , Zhang Haixia
Published: March 2014

A novel doxorubicin (DOX) prodrug (MPEG-b-DOX) was synthesized that reduces the proportion of inactive materials and minimizes drug leak.
A chemiluminescence excited photoelectrochemistry aptamer-device equipped with a tin dioxide quantum dot/reduced graphene oxide nanocomposite modified porous Au-paper electrode
Authors: Wang Yanhu , Xu Jinmeng , Ma Chao , Li Shuai , Yu Jinghua , Ge Shenguang , Yan Mei
Published: March 2014

A paper-based chemiluminescence excited photoelectrochemical aptamer device integrated with an all-solid-state paper supercapacitor was demonstrated.
A Fab fragment directed against the neural cell adhesion molecule L1 enhances functional recovery after injury of the adult mouse spinal cord
Authors: Loers Gabriele , Cui Yi-Fang , Neumaier Irmgard , Schachner Melitta , Skerra Arne
Published: March 2014

Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery, which leads to severe disabilities in motor functions or pain. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration. In the present study, we describe the cloning, functional expression in Escherichia coli cells and purification of a recombinant αL1 Fab fragment that binds to L1 with comparable activity as the function-triggering monoclonal antibody 557.B6 and induces neurite outgrowth and neuronal survival in cultured neurons, despite its monovalent function. Infusion of αL1 Fab into the lesioned spinal cord of mice enhanced functional recovery after thoracic spinal cord compression injury. αL1 Fab treatment resulted in reduced scar volume, enhanced number of tyrosine hydroxylase-positive axons and increased linear density of VGLUT1 (vesicular glutamate transporter 1) on motoneurons. Furthermore, the number and soma size of ChAT (choline acetyltransferase)-positive motoneurons and the linear density of ChAT-positive boutons on motoneurons as well as parvalbumin-positive interneurons in the lumbar spinal cord were elevated. Stimulation of endogenous L1 by application of the αL1 Fab opens new avenues for recombinant antibody technology, offering prospects for therapeutic applications after traumatic nervous system lesions.
Magnetic-field-sensing mechanism based on dual-vortex motion and magnetic noise
Authors: Zeng Tui , Zhou Yan , Lin Ko-Wei , Lai Pui-To , Pong Philip W. T.
Published: March 2014

In this study, we report two novel field sensing mechanisms using elliptical permalloy single layer. Using micromagnetic modeling, dual-vortex structure is observed and stabilized in elliptical permalloy single layer by applying hard bias field (along the y-axis) and vertical axis field (perpendicular to plane). During the increasing or decreasing of the hard bias field within certain range, the dual vortices would move away from or approach to each other at a constant velocity, leading to a positive correlation between the hard bias field and the vortex gap. By exploring the magnetic noise properties of the elliptical permalloy single layer under various vortex gap, the vortex gap is found to be positively correlated with both the FMR (Ferromagnetic Resonance) peak positions and the integrated thermally excited mag-noise. Therefore, the combination of the dual-vortex motion and the magnetic noise properties make it possible to measure external field (along hard bias direction) through measuring the FMR peak positions or integrated thermally mag-noise. This FMR-peak-based field sensing mechanism and integrated-noise-based field sensing introduce a simple field sensor structure with expected highest sensitivity to 1.1%/Oe and field detectable range over 1000 Oe, which is promising for potential sensor applications.
Synthesis of nonstoichiometric titanium oxide nanoparticles using discharge in HCl solution
Authors: Nakasugi Yuki , Saito Genki , Yamashita Toru , Akiyama Tomohiro
Published: March 2014

This study demonstrates the synthesis of nonstoichiometric titanium oxide (TiO2−δ) nanoparticles using plasma discharge. We have primarily investigated the effect of electrolyte concentration and edge shielding of electrode on the morphology, and oxygen defects of the final product. As a precursor for nanoparticle synthesis, titanium wire was utilized as a cathode, which was immersed in an HCl electrolyte in the concentration range of 0.1–5.0 M. The electrode edge was shielded to maintain uniform distribution of electric current. For comparison, we also used an electrode without edge shielding. Systematic studies indicate that the as-prepared products were spherical titanium oxide nanoparticles, the size of which decreased with decrease in electrolyte concentration. The edge shielding of the electrode was found to affect the size distribution and oxidation degree of the products. In case of the edge-shielded electrode, the oxidation of the product was suppressed, resulting in a product composition of TiO1.72. In contrast, in case of the electrode without edge shielding, the oxidation of the products was favored, resulting in formation of TiO1.90. This could be attributed to the concentration of electric current at the electrode edge, in which the heating-up of the electrode edge enhanced the oxidation of the product. These results confirm the possibility of synthesizing nonstoichiometric oxide nanoparticles with controllable oxygen defects by using plasma discharge in HCl solution.
Successful fabrication of high Ku columnar CoPt-SiO2 granular film sputtered under high substrate temperature
Authors: Kong Tham Kim , Hinata Shintaro , Saito Shin , Takahashi Migaku
Published: March 2014

High substrate temperature sputtered CoPt-SiO2 granular films with columnar grain structure, high perpendicular uniaxial magnetic anisotropy (Ku⊥), and low stacking faults (SFs) are reported. By introducing a CoCr-SiO2 buffer layer onto a Ru layer, SiO2 segregates to Ru grains boundaries and CoCr grains grow epitaxially onto Ru grains. Consequently, the bumpy surface morphology of the underlayer is maintained even though the temperature of the substrate heating is subsequently elevated to around 400 °C. Therefore, the CoPtCr magnetic grains of the CoPtCr-SiO2 granular recording layer can grow epitaxially with columnar structure upon the CoCr grains of the CoCr-SiO2 buffer layer. For deposition of CoPt-SiO2 (no Cr) granular films at the substrate temperature below 400 °C, the increase of SFs can be suppressed such that Ku⊥ can be kept high at around 6.5 × 106 ergs/cm3 (Kugrain of around 9.0 × 106 ergs/cm3, where Kugrain is referred to uniaxial magneto-crystalline anisotropy of the magnetic grains when oxide material is excluded from the granular layer).
Predissociation of high-lying Rydberg states of molecular iodine via ion-pair states
Authors: Bogomolov Alexandr S. , Grüner Barbara , Kochubei Sergei A. , Mudrich Marcel , Baklanov Alexey V.
Published: March 2014

Velocity map imaging of the photofragments arising from two-photon photoexcitation of molecular iodine in the energy range 73 500–74 500 cm−1 covering the bands of high-lying gerade Rydberg states [2Π1/2]c6d;0g+ and [2Π1/2]c6d;2g has been applied. The ion signal was dominated by the atomic fragment ion I+. Up to 5 dissociation channels yielding I+ ions with different kinetic energies were observed when the I2 molecule was excited within discrete peaks of Rydberg states and their satellites in this region. One of these channels gives rise to images of I+ and I− ions with equal kinetic energy indicating predissociation of I2 via ion-pair states. The contribution of this channel was up to about 50% of the total I+ signal. The four other channels correspond to predissociation via lower lying Rydberg states giving rise to excited iodine atoms providing I+ ions by subsequent one-photon ionization by the same laser pulse. The ratio of these channels varied from peak to peak in the spectrum but their total ionic signal was always much higher than the signal of (2 + 1) resonance enhanced multi-photon ionization of I2, which was previously considered to be the origin of ionic signal in this spectral range. The first-tier E0g+ and D′2g ion-pair states are concluded to be responsible for predissociation of Rydberg states [2Π1/2]c6d;0g+ and [2Π1/2]c6d;2g, respectively. Further predissociation of these ion-pair states via lower lying Rydberg states gives rise to excited I(5s25p46s1) atoms responsible for major part of ion signal. The isotropic angular distribution of the photofragment recoil directions observed for all channels indicates that the studied Rydberg states are long-lived compared with the rotational period of the I2 molecule.
Quantum-enhanced metrology based on Fabry-Perot interferometer by squeezed vacuum and non-Gaussian detection
Authors: Li Wenfang , Du Jinjin , Wen Ruijuan , Li Gang , Zhang Tiancai
Published: March 2014

We have investigated the transmission spectra of a Fabry-Perot interferometer (FPI) with squeezed vacuum state injection and non-Gaussian detection, including photon number resolving detection and parity detection. In order to show the suitability of the system, parallel studies were made of the performance of two other light sources: coherent state of light and Fock state of light either with classical mean intensity detection or with non-Gaussian detection. This shows that by using the squeezed vacuum state and non-Gaussian detection simultaneously, the resolution of the FPI can go far beyond the cavity standard bandwidth limit based on the current techniques. The sensitivity of the scheme has also been explored and it shows that the minimum detectable sensitivity is better than that of the other schemes.
Role of interface structure and chemistry in resistive switching of NiO nanocrystals on SrTiO3
Authors: Cheng Xuan , Sullaphen Jivika , Weyland Matthew , Liu Hongwei , Valanoor Nagarajan
Published: March 2014

Nickel oxide (NiO) nanocrystals epitaxially grown on (001) strontium titanate (SrTiO3) single crystal substrates were characterized to investigate interface morphology and chemistry. Aberration corrected high angle annular dark field scanning transmission electron microscopy reveals the interface between the NiO nanocrystals and the underlying SrTiO3 substrate to be rough, irregular, and have a lower average atomic number than the substrate or the nanocrystal. Energy dispersive x-ray spectroscopy and electron energy loss spectroscopy confirm both chemical disorder and a shift of the energy of the Ti L2,3 peaks. Analysis of the O K edge profiles in conjunction with this shift, implies the presence of oxygen vacancies at the interface. This sheds light into the origin of the previously postulated minority carriers’ model to explain resistive switching in NiO [J. Sullaphen, K. Bogle, X. Cheng, J. M. Gregg, and N. Valanoor, Appl. Phys. Lett. 100, 203115 (2012)].
Enzyme transient state kinetics in crystal and solution from the perspective of a time-resolved crystallographer
Authors: Schmidt Marius , Saldin Dilano K.
Published: March 2014

With recent technological advances at synchrotrons [Graber et al., J. Synchrotron Radiat. 18, 658–670 (2011)], it is feasible to rapidly collect time-resolved crystallographic data at multiple temperature settings [Schmidt et al., Acta Crystallogr. D 69, 2534–2542 (2013)], from which barriers of activation can be extracted. With the advent of fourth generation X-ray sources, new opportunities emerge to investigate structure and dynamics of biological macromolecules in real time [M. Schmidt, Adv. Condens. Matter Phys. 2013, 1–10] in crystals and potentially from single molecules in random orientation in solution [Poon et al., Adv. Condens. Matter Phys. 2013, 750371]. Kinetic data from time-resolved experiments on short time-scales must be interpreted in terms of chemical kinetics [Steinfeld et al., Chemical Kinetics and Dynamics, 2nd ed. (Prentience Hall, 1985)] and tied to existing time-resolved experiments on longer time-scales [Schmidt et al., Acta Crystallogr. D 69, 2534–2542 (2013); Jung et al., Nat. Chem. 5, 212–220 (2013)]. With this article, we will review and outline steps that are required to routinely determine the energetics of reactions in biomolecules in crystal and solution with newest X-ray sources. In eight sections, we aim to describe concepts and experimental details that may help to inspire new approaches to collect and interpret these data.
Coercivity and exchange bias of bismuth ferrite nanoparticles isolated by polymer coating
Authors: Chaturvedi Smita , Shirolkar Mandar M. , Rajendra Ranguwar , Singh Surjeet , Ballav Nirmalya , Kulkarni Sulabha
Published: March 2014

Bismuth ferrite nanoparticles have been extensively investigated over the last few years due to their potential candidacy for application in future memory devices. However, all the work reported so far on bismuth ferrite nanoparticles is on agglomerated nanoparticles. Agglomerated particles can magnetically interact with each other. To utilize them for device application, it is useful to know the properties of the individual particles. Here, de-agglomeration of ∼75 nm bismuth ferrite nanoparticles is achieved by polyaniline coating on the surface. The structural and magnetic properties of agglomerated and de-agglomerated nanoparticles are compared. It is observed that there is a change in the lattice parameters and Fe-O-Fe and O-Bi-O bond angles due to polyaniline shell. The coercivity of the bismuth ferrite/polyaniline core shell particles is reduced as compared to pure and agglomerated bismuth ferrite particles. The observed changes in the magnetic properties of coated particles are attributed to the shell induced isolation of individual bismuth ferrite nanoparticles as well as structural changes due to polyaniline coating.
Charge disproportionation in La1-xCaxFeO3−δ (x = 0.4 and 0.5) investigated by mechanical spectroscopy
Authors: Xu Z. C. , Liu M. F. , Chen C. C. , Ying X. N.
Published: March 2014

The nature of charge disproportionation in orthorhombic lanthanum orthoferrites La1-xCaxFeO3-δ (x = 0.4 and 0.5) has been investigated by kilohertz mechanical spectroscopy. Contrast to rhombohedral La1-xSrxFeO3-δ (x = 0.5), no elastic softening was observed in La1-xCaxFeO3-δ above charge disproportionation. This different behavior of elastic modulus in La1-xCaxFeO3-δ and La1-xSrxFeO3-δ unveils the implicit orbital effect. Below charge disproportionation, an internal friction peak around 140 K was observed in La1-xCaxFeO3-δ, which is similar to that in La1-xSrxFeO3-δ. This peak is ascribed to an elastic manifestation of charge freezing and can be used as an indirect indication of CD in doped LaFeO3.
Viscoelastic effects on frequency tuning of a dielectric elastomer membrane resonator
Authors: Zhou Jianyou , Jiang Liying , Khayat Roger E.
Published: March 2014

As a recent application of dielectric elastomers (DEs), DE resonators have become an alternative to conventional silicon-based resonators used in MEMS and have attracted much interest from the research community. However, most existing modeling works for the DE resonators ignore the intrinsic viscoelastic effect of the material that may strongly influence their dynamic performance. Based on the finite-deformation viscoelasticity theory for dielectrics, this paper theoretically examines the in-plane oscillation of a DE membrane resonator to demonstrate how the material viscoelasticity affects the actuation and frequency tuning processes of the resonator. From the simulation results, it is concluded that not only the applied voltage can change the natural frequency of the resonator, but also the inelastic deformation contributes to frequency tuning. Due to the viscoelasticity of the material, the electrical loading rate influences the actuation process of the DE resonator, while it has little effect on the final steady frequency tuned by the prescribed voltage within the safety range. With the consideration of the typical failure modes of the resonator and the evolution process of the material, the tunable frequency range and the safe range of the applied voltage of the DE membrane resonator with different dimension parameters are determined in this work, which are found to be dependent on the electrical loading rate. This work is expected to provide a better understanding on the frequency tuning of viscoelastic DE membrane resonators and a guideline for the design of DE devices.
Communication: Resolving the three-body contribution to the lattice energy of crystalline benzene: Benchmark results from coupled-cluster theory
Authors: Kennedy Matthew R. , McDonald Ashley Ringer , DePrince A. Eugene , Marshall Michael S. , Podeszwa Rafal , Sherrill C. David
Published: March 2014

Coupled-cluster theory including single, double, and perturbative triple excitations [CCSD(T)] has been applied to trimers that appear in crystalline benzene in order to resolve discrepancies in the literature about the magnitude of non-additive three-body contributions to the lattice energy. The present results indicate a non-additive three-body contribution of 0.89 kcal mol−1, or 7.2% of the revised lattice energy of −12.3 kcal mol−1. For the trimers for which we were able to compute CCSD(T) energies, we obtain a sizeable difference of 0.63 kcal mol−1 between the CCSD(T) and MP2 three-body contributions to the lattice energy, confirming that three-body dispersion dominates over three-body induction. Taking this difference as an estimate of three-body dispersion for the closer trimers, and adding an Axilrod-Teller-Muto estimate of 0.13 kcal mol−1 for long-range contributions yields an overall value of 0.76 kcal mol−1 for three-body dispersion, a significantly smaller value than in several recent studies.
Ab initio studies on phase transition, thermoelastic, superconducting and thermodynamic properties of the compressed cubic phase of AlH3
Authors: Wei Yong-Kai , Ge Ni-Na , Chen Xiang-Rong , Ji Guang-Fu , Cai Ling-Cang , Gu Zhuo-Wei
Published: March 2014

The phase transition, thermoelastic, lattice dynamic, and thermodynamic properties of the cubic metallic phase AlH3 were obtained within the density-function perturbation theory. The calculated elastic modulus and phonon dispersion curves under various pressures at 0 K indicate the cubic phase is both mechanically and dynamically stable above 73 GPa. The superconducting transition temperature Tc was calculated using the Allen-Dynes modification of the McMillan formula based on BCS theory. The calculations show that Tc for the cubic phase AlH3 is 8.5 K (μ*=0.1) at the onset of this phase (73 GPa), while decreases to 5.7 K at 80 GPa and almost disappears at 110 GPa, consisting with experimental phenomenon that there was no superconducting transition observed down to 4 K over a wide pressure range 110–164 GPa. It is found that the soft phonon mode for branch 1, namely, the lowest acoustic mode, plays a crucial role in elevating the total EPC parameter λ of cubic AlH3. And the evolution of Tc with pressure follows the corresponding change of this soft mode, i.e. this mode is responsible for the disappearance of Tc in experiments. Meanwhile, the softening of this lowest acoustic mode originates from the electronic momentum transfer from M to R point. This phenomenon provides an important insight into why drastic changes in the diffraction pattern were observed in the pressure range of 63–73 GPa in Goncharenko's experiments. Specifically, once finite electronic temperature effects are included, we find that dynamical instabilities can be removed in the phonon dispersion for P≥63 GPa, rendering the metastability of this phase in the range of 63–73 GPa, and Tc (15.4 K) becomes remarkably high under the lowest possible pressure (63 GPa) compared with that of under 73 GPa (8.5 K). Our calculations open the possibility that finite temperature may allow cubic AlH3 to be dynamically stabilized even for pressures below 73 GPa. It is reasonable to deduced that if special techniques, such as rapid decompression, quenching, and annealing, are implemented in experiments, higher Tc can be observed in hydrides or hydrogen-rich compounds under much lower pressure than ever before.
On the redox origin of surface trapping in AlGaN/GaN high electron mobility transistors
Authors: Gao Feng , Chen Di , Tuller Harry L. , Thompson Carl. V. , Palacios Tomás
Published: March 2014

Water-related redox couples in ambient air are identified as an important source of the surface trapping states, dynamic on-resistance, and drain current collapse in AlGaN/GaN high electron mobility transistors (HEMTs). Through in-situ X-ray photoelectron spectroscopy (XPS), direct signature of the water-related species—hydroxyl groups (OH) was found at the AlGaN surface at room temperature. It was also found that these species, as well as the current collapse, can be thermally removed above 200 °C in vacuum conditions. An electron trapping mechanism based on the H2O/H2 and H2O/O2 redox couples is proposed to explain the 0.5 eV energy level commonly attributed to the surface trapping states. Finally, the role of silicon nitride passivation in successfully removing current collapse in these devices is explained by blocking the water molecules away from the AlGaN surface.
CdS/PbSe heterojunction for high temperature mid-infrared photovoltaic detector applications
Authors: Weng Binbin , Qiu Jijun , Zhao Lihua , Chang Caleb , Shi Zhisheng
Published: March 2014

n-CdS/p-PbSe heterojunction is investigated. A thin CdS film is deposited by chemical bath deposition on top of epitaxial PbSe film by molecular beam epitaxy on Silicon. Current-voltage measurements demonstrate very good junction characteristics with rectifying ratio of ∼178 and ideality factor of 1.79 at 300 K. Detectors made with such structure exhibit mid-infrared spectral photoresponse at room temperature. The peak responsivity Rλ and specific detectivity D* are 0.055 A/W and 5.482 × 108 cm·Hz1/2/W at λ = 4.7 μm under zero-bias photovoltaic mode. Temperature-dependent photoresponse measurements show abnormal intensity variation below ∼200 K. Possible reasons for this phenomenon are also discussed.
Magnetic field and mechanical stress tunable microwave properties of composites containing Fe-based microwires
Authors: Luo Y. , Peng H. X. , Qin F. X. , Adohi B. J. P. , Brosseau C.
Published: March 2014

We report the magnetic field and stress tunable microwave behaviour of microwire-epoxy composites containing Fe-based microwires of different lengths. Observation of a crossover magnetic field at 600 Oe, when the wire length is less than 35 mm, is reasoned to be related to the competition between giant magnetoimpedance and ferromagnetic resonance in addition to the wire's intrinsic properties. Samples containing 25 mm microwires exhibit a linear increase of the permittivity tunability as the tensile strain is increased up to 2.0%. This can be attributed to the longitudinal anisotropy field and the wire alignment under strain.
Broadband asymmetric transmission of optical waves from spiral plasmonic metamaterials
Authors: Pan Chongpei , Ren Mengxin , Li Qunqing , Fan Shoushan , Xu Jingjun
Published: March 2014

This study theoretically demonstrates a broadband circular asymmetric transmission effect on the basis of two dimensional planar spiral metamaterials. We found that by increasing the number of turns in a single spiral unit cell, the bandwidth of the asymmetric transmission effect will be broaden dramatically and reach to about 940 nm in the near-infrared spectral range.
Negative magnetoresistance in undoped semiconducting amorphous carbon films
Authors: Ur Rehman Sagar Rizwan , Zhang Xiaozhong , Wang Jimin , Xiong Chengyue
Published: March 2014

Amorphous carbon (a-C) films were fabricated by chemical vapor deposition on SiO2 substrate. The a-C films have nano-crystalline sp2 structure with the grain size of ∼5 nm and an optical band gap of ∼1.8 eV. The a-C films show negative magnetoresistance (MR) from 300 to 2 K and an anomalous shape change of MR-magnetic field curves at 10 K. Grain boundary scattering theory and weak localization theory were used to explain the MR mechanism and shape change of MR-magnetic field curves.
Magnetic properties of mixed spinel BaTiO3-NiFe2O4 composites
Authors: Sarkar Babusona , Dalal Biswajit , Dev Ashok Vishal , Chakrabarti Kaushik , Mitra Amitava , De S. K.
Published: March 2014

Solid solution of nickel ferrite (NiFe2O4) and barium titanate (BaTiO3), (100-x)BaTiO3–(x) NiFe2O4 has been prepared by solid state reaction. Compressive strain is developed in NiFe2O4 due to mutual structural interaction across the interface of NiFe2O4 and BaTiO3 phases. Quantitative analysis of X-ray diffraction and X-ray photo electron spectrum suggest mixed spinel structure of NiFe2O4. A systematic study of composition dependence of composite indicates BaTiO3 causes a random distribution of Fe and Ni cations among octahedral and tetrahedral sites during non-equilibrium growth of NiFe2O4. The degree of inversion decreases monotonically from 0.97 to 0.75 with increase of BaTiO3 content. Temperature dependence of magnetization has been analyzed by four sublattice model to describe complex magnetic exchange interactions in mixed spinel phase. Curie temperature and saturation magnetization decrease with increase of BaTiO3 concentration. Enhancement of strain and larger occupancy of Ni2+ at tetrahedral site increase coercivity up to 200 Oe. Magnetostructual coupling induced by BaTiO3 improves coercivity in NiFe2O4. An increase in the demagnetization and homogeneity in magnetization process in NiFe2O4 is observed due to the interaction with diamagnetic BaTiO3.
Low temperature magneto-photoluminescence of GaAsBi /GaAs quantum well heterostructures
Authors: Mazur Yu. I. , Teodoro M. D. , Dias de Souza L. , Ware M. E. , Fan D. , Yu S.-Q. , Tarasov G. G. , Marques G. E. , Salamo G. J.
Published: March 2014

Strong optical anisotropy is observed in the emission from a GaAs1−xBix (x ∼ 0.04) quantum well grown by low temperature molecular beam epitaxy on (001) GaAs by means of low temperature magneto-photoluminescence (MPL) taken at 2 K in Faraday geometry for magnetic fields, B, up to 10 T. A significant diamagnetic shift (∼2.5 meV) develops for magnetic fields above ∼8 T, which is accompanied by a narrowing of the emission bandwidth and a substantial increase in the difference between the integrated intensities of the σ+ and σ− polarizations in the MPL spectra. This, along with a peculiar spectral dependence of the polarization degree which evolves with increasing magnetic field, is interpreted in terms of bound and free magneto excitons in the system where Bi-related levels become hybridized to different extents with the valence and conduction bands of the GaAs host material.
A passive measurement of dissociated atom densities in atmospheric pressure air discharge plasmas using vacuum ultraviolet self-absorption spectroscopy
Authors: Laity George , Fierro Andrew , Dickens James , Frank Klaus , Neuber Andreas
Published: March 2014

We demonstrate a method for determining the dissociation degree of atmospheric pressure air discharges by measuring the self-absorption characteristics of vacuum ultraviolet radiation from O and N atoms in the plasma. The atom densities are determined by modeling the amount of radiation trapping present in the discharge, without the use of typical optical absorption diagnostic techniques which require external sources of probing radiation into the experiment. For an 8.0 mm spark discharge between needle electrodes at atmospheric pressure, typical peak O atom densities of 8.5 × 1017 cm−3 and peak N atom densities of 9.9 × 1017 cm−3 are observed within the first ∼1.0 mm of plasma near the anode tip by analyzing the OI and NI transitions in the 130.0–132.0 nm band of the vacuum ultraviolet spectrum.
Semiconductor/dielectric half-coaxial nanowire arrays for large-area nanostructured photovoltaics
Authors: Hua X. , Zeng Y. , Shen W. Z.
Published: March 2014

We present a simple assembly strategy of single nanowires (NWs) to form half-coaxial nanowire arrays (NWAs) which can be easily realized in large size by standard pattering and deposition techniques. Through the finite-difference time-domain simulation, we show that the proposed half-coaxial NWAs effectively preserve the leaky modes resonances within single NWs and consequently achieve strong absorption enhancement under optimization of various structural factors. The best half-coaxial NWAs with 100 nm thick absorbing shell offer equivalent light absorption of more than 400 nm thick planar film. Benefiting from the >75% cut of the required thickness of the absorbing layer, the performances of the demonstrated half-coaxial NWAs based a-Si thin film solar cell also gain significant improvement.
Essential ingredients in core-collapse supernovae
Authors: Hix W. Raphael , Lentz Eric J. , Endeve Eirik , Baird Mark , Chertkow M. Austin , Harris J. Austin , Messer O. E. Bronson , Mezzacappa Anthony , Bruenn Stephen , Blondin John
Published: March 2014

Carrying 1044 joules of kinetic energy and a rich mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up our solar system and ourselves. Signaling the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae combine physics over a wide range in spatial scales, from kilometer-sized hydrodynamic motions (eventually growing to gigameter scale) down to femtometer-scale nuclear reactions. We will discuss our emerging understanding of the convectively-unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have recently motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of the births of neutron stars and the supernovae that result. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.
Tunneling characteristics in chemical vapor deposited graphene–hexagonal boron nitride–graphene junctions
Authors: Roy T. , Liu L. , de la Barrera S. , Chakrabarti B. , Hesabi Z. R. , Joiner C. A. , Feenstra R. M. , Gu G. , Vogel E. M.
Published: March 2014

Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate graphene–hexagonal boron nitride–graphene symmetric field effect transistors. Gate control of the tunneling characteristics is observed similar to previously reported results for exfoliated graphene–hexagonal boron nitride–graphene devices. Density-of-states features are observed in the tunneling characteristics of the devices, although without large resonant peaks that would arise from lateral momentum conservation. The lack of distinct resonant behavior is attributed to disorder in the devices, and a possible source of the disorder is discussed.
On the scalability of doped hafnia thin films
Authors: Adelmann C. , Schram T. , Chew S.-A. , Woicik J. C. , Brizzi S. , Tallarida M. , Schmeisser D. , Horiguchi N. , Van Elshocht S. , Ragnarsson L.-Å.
Published: March 2014

The scaling behavior of Gd- and Al-doped HfO2 films as gate dielectrics in metal-oxide-semiconductor (MOS) capacitors was studied. For equivalent oxide thicknesses (EOTs) in the range of 10 Å, crystallized Gd:HfO2 showed higher leakage current densities than crystallized Al:HfO2, with undoped HfO2 in between. Ultimately, the scalability of Al:HfO2 was limited by the ability to crystallize the films at a given thermal budget. As a result, for post-deposition annealing at 800 °C, the EOT of Al:HfO2 based MOS capacitors was limited to ∼8 Å. However, for such an EOT, leakage current densities were reduced by about 100× with respect to HfO2. This demonstrates the high potential of Al:HfO2 for low-standby-power MOS devices.
Comparative study of the alloying effect on the initial oxidation of Cu-Au(100) and Cu-Pt(100)
Authors: Luo Langli , Kang Yihong , Yang Judith C. , Su Dong , Stach Eric A. , Zhou Guangwen
Published: March 2014

Using in situ transmission electron microscopy, we show that the oxidation of the Cu-Au(100) results in the formation of Cu2O islands that deeply embed into the Cu-Au substrate while the oxidation of the Cu-Pt(100) leads to the formation of Cu2O islands that highly protrude above the Cu-Pt substrate. Their difference is attributed to the different mobilities of Pt and Au in the Cu base alloys for which the sluggish mobility of Pt in Cu results in trapped Pt atoms at the oxide/alloy interface while the faster mobility of Au in Cu leads to enhanced rehomogenization of the alloy composition.
The Right to Infrastructure: A Prototype for Open Source Urbanism
Authors: Jiménez Alberto Corsín
Published: March 2014

This paper develops an analytical framework to place the rise of open source urbanism in context, and develops the concept of the ‘right to infrastructure’ as expressive of new ecologies of urban relations that have come into being. It describes, first, a genealogy for open source technology, focusing in particular on how open source urban hardware projects may challenge urban theory. It moves then to describe in detail various dimensions and implications of an open source infrastructural project in Madrid. In all, the paper analyses three challenges that the development of open source urban infrastructures is posing to the institutions of urban governance and property: the evolving shape and composition of urban ecologies; the technical and design challenges brought about by open source urban projects; and the social organisation of the ‘right to infrastructure’ as a political, active voice in urban governance. In the last instance, the right to infrastructure, I shall argue, signals the rise of the ‘prototype’ as an emerging figure for contemporary sociotechnical designs in and for social theory.
Characterisation of mussel (Mytilus sp.) populations in Western Australia and evaluation of potential genetic impacts of mussel spat translocation from interstate
Authors: Dias P. Joana , Fotedar Seema , Snow Michael
Published: March 2014

In the present study, we investigate the potential impact of the first proposed interstate translocation of mussel spat, for aquaculture enhancement, on the genetic integrity of Mytilus populations in Western Australia (WA). We performed genetic analysis on four populations (Garden Island, Bunbury, Albany and Esperance) in WA and on mussels from three hatcheries in South Australia (SA), Victoria (Vic) and Tasmania (Tas) proposed as spat sources in the translocation application. Two genetically distinct groups of M. galloprovincialis were identified, which corresponded to introduced Northern Hemisphere and native Southern Hemisphere haplotypes. Mussels obtained from the hatcheries showed a marked proportion of native haplotypes, while mussels of three (Garden Island, Bunbury and Esperance) of the four sampled WA Mytilus populations consisted mostly of introduced haplotypes. Most importantly, all samples were notable for a mixture of native and introduced haplotypes with the great majority of introduced haplotypes occurring in both WA and eastern states samples. Based on these results, it seems unlikely that the proposed translocation of mussel spat could negatively impact WA Mytilus populations. The current study presents valuable information regarding the genetic composition of Mytilus populations and will prove useful in the assessment of future translocation applications and biodiversity of mussel species in WA.
Pre‐service teachers’ assessment literacy and its implementation into practice
Authors: Ogan‐Bekiroglu Feral , Suzuk Erol
Published: March 2014

This research study was conducted to address pre‐service physics teachers’ assessment literacy and its implementation into practice. The research was both quantitative and qualitative in nature. For the quantitative aspect of the study, the researchers determined the participants’ assessment literacy after their enrolment with the assessment course. Intentions of the qualitative part were to validate the results drawn from the quantitative research and to examine the participants’ assessment literacy in the practical realm. Data were collected by using a valid and reliable instrument developed by the first author, a questionnaire and the participants’ project assignment including implementation of assessment. According to the quantitative results, the pre‐service physics teachers’ assessment literacy was quite high. Findings obtained from the qualitative analyses were compatible with the quantitative results. However, the study revealed gaps between assessment literacy in theory and practice. This study suggests that teacher education programmes should highlight theories of assessment as well as types of evaluation, stress validity and reliability of assessment enabling students to engage in both traditional and performance‐based assessment methods, and provide opportunities for students to reflect, practice, and revise these methods.
Explicit barycentric weights for polynomial interpolation in the roots or extrema of classical orthogonal polynomials
Authors: Wang Haiyong , Huybrechs Daan , Vandewalle Stefan
Published: March 2014

Barycentric interpolation is arguably the method of choice for numerical polynomial interpolation. The polynomial interpolant is expressed in terms of function values using the so-called barycentric weights, which depend on the interpolation points. Few explicit formulae for these barycentric weights are known. In [H. Wang and S. Xiang, Math. Comp., 81 (2012), 861–877], the authors have shown that the barycentric weights of the roots of Legendre polynomials can be expressed explicitly in terms of the weights of the corresponding Gaussian quadrature rule. This idea was subsequently implemented in the Chebfun package [L. N. Trefethen and others, The Chebfun Development Team, 2011] and in the process generalized by the Chebfun authors to the roots of Jacobi, Laguerre and Hermite polynomials. In this paper, we explore the generality of the link between barycentric weights and Gaussian quadrature and show that such relationships are related to the existence of lowering operators for orthogonal polynomials. We supply an exhaustive list of cases, in which all known formulae are recovered and also some new formulae are derived, including the barycentric weights for Gauss-Radau and Gauss-Lobatto points. Based on a fast

O

(
n
)

{\mathcal O}(n)

algorithm for the computation of Gaussian quadrature, due to Hale and Townsend, this leads to an

O

(
n
)

{\mathcal O}(n)

computational scheme for barycentric weights.
CAGExploreR: an R package for the analysis and visualization of
promoter dynamics across multiple experiments
Authors: Dimont Emmanuel , Hofmann Oliver , Ho Sui Shannan J , Forrest Alistair R R , Kawaji Hideya , Hide Winston ,   the FANTOM Consortium
Published: March 2014

Alternate promoter usage is an important molecular mechanism for generating RNA and protein diversity. Cap Analysis Gene Expression (CAGE) is a powerful approach for revealing the multiplicity of transcription start site (TSS) events across experiments and conditions. An understanding of the dynamics of TSS choice across these conditions requires both sensitive quantification and comparative visualization. We have developed CAGExploreR, an R package to detect and visualize changes in the use of specific TSS in wider promoter regions in the context of changes in overall gene expression when comparing different CAGE samples. These changes provide insight into the modification of transcript isoform generation and regulatory network alterations associated with cell types and conditions. CAGExploreR is based on the FANTOM5 and MPromDb promoter set definitions but can also work with user-supplied regions. The package compares multiple CAGE libraries simultaneously. Supplementary Materials describe methods in detail, and a vignette demonstrates a workflow with a real data example.

Availability and implementation: The package is freely available under the MIT license from CRAN (http://cran.r-project.org/web/packages/CAGExploreR).

Contact:  edimont@mail.harvard.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
Plant Growth Promotion by Spermidine-Producing Bacillus subtilis OKB105
Authors: Xie Shan-Shan , Wu Hui-Jun , Zang Hao-Yu , Wu Li-Ming , Zhu Qing-Qing , Gao Xue-Wen
Published: March 2014

The interaction between plants and plant-growth-promoting rhizobacteria (PGPR) is a complex, reciprocal process. On the one hand, plant compounds such as carbohydrates and amino acids serve as energy sources for PGPR. On the other hand, PGPR promote plant growth by synthesizing plant hormones and increasing mineral availability in the soil. Here, we evaluated the growth-promoting activity of Bacillus subtilis OKB105 and identified genes associated with this activity. The genes yecA (encoding a putative amino acid/polyamine permease) and speB (encoding agmatinase) are involved in the secretion or synthesis of polyamine in B. subtilis OKB105. Disruption of either gene abolished the growth-promoting activity of the bacterium, which was restored when polyamine synthesis was complemented. Moreover, high-performance liquid chromatography analysis of culture filtrates of OKB105 and its derivatives demonstrated that spermidine, a common polyamine, is the pivotal plant-growth-promoting compound. In addition, real-time polymerase chain reaction analysis revealed that treatment with B. subtilis OKB105 induced expansin gene (Nt-EXPA1 and Nt-EXPA2) expression and inhibited the expression of the ethylene biosynthesis gene ACO1. Furthermore, enzyme-linked immunosorbent assay analysis showed that the ethylene content in plant root cells decreased in response to spermidine produced by OKB105. Therefore, during plant interactions, OKB105 may produce and secrete spermidine, which induces expansin production and lowers ethylene levels.
The de novo Biosynthesis of Vitamin B6 Is Required for Disease Resistance Against Botrytis cinerea in Tomato
Authors: Zhang Yafen , Liu Bo , Li Xiaohui , Ouyang Zhigang , Huang Lei , Hong Yongbo , Zhang Huijuan , Li Dayong , Song Fengming
Published: March 2014

Vitamin B6 (VB6), an essential cofactor for numerous metabolic enzymes, has recently been shown to act as a potent antioxidant and play important roles in developmental processes and stress responses. However, little is known about the possible function of VB6 in plant disease resistance response against pathogen infection. In the present study, we explored the possible involvement of VB6 in defense response against Botrytis cinerea through functional analysis of tomato VB6 biosynthetic genes. Three de novo VB6 biosynthetic genes (SlPDX1.2, SlPDX1.3, and SlPDX2) and one salvage pathway gene (SlSOS4) were identified and the SlPDX1.2, SlPDX1.3, and SlPDX2 genes were shown to encode functional enzymes involved in de novo biosynthesis of VB6, as revealed by complementation of the VB6 prototrophy in yeast snz1 and sno1 mutants. Expression of SlPDX1.2, SlPDX1.3, and SlSOS4 genes was induced by infection with B. cinerea. Virus-induced gene silencing-mediated knockdown of SlPDX1.2 or SlPDX1.3 but not SlPDX2 and SlSOS4 led to increased severity of disease caused by B. cinerea, indicating that the VB6 de novo biosynthetic pathway but not the salvage pathway is involved in tomato defense response against B. cinerea. Furthermore, the SlPDX1.2- and SlPDX1.3-silenced tomato plants exhibited reduced levels of VB6 contents and reactive oxygen species scavenging capability, increased levels of superoxide anion and H2O2 generation, and increased activity of superoxide dismutase after infection by B. cinerea. Our results suggest that VB6 and its de novo biosynthetic pathway play important roles in regulation of defense response against B. cinerea through modulating cellular antioxidant capacity.
Survival, Persistence, and Infection Efficiency of Verticillium dahliae Passed Through the Digestive System of Sheep
Authors: Markakis Emmanouil A. , Ligoxigakis Eleftherios K. , Avramidou Evangelia V. , Tzanidakis Nikolaos
Published: March 2014

The present study was carried out to determine the survival, persistence, and infection efficiency of Verticillium dahliae passed through the digestive tract of sheep. Eggplant, turnip, tomato, and pepper plants were artificially inoculated with 32 V. dahliae isolates. At 33 days postinoculation, the disease incidence and severity for eggplant, turnip, tomato, and pepper plants were 99.6, 96.2, 62.9, and 18.0% and 80.1, 49.8, 19.8, and 7.8%, respectively. The infected plant material was used to feed four 1-year-old sheep. Polymerase chain reaction assays revealed the presence of V. dahliae DNA in fecal samples received from animals' rectum on days 1, 2, 3, 4, and 5, whereas the pathogen DNA was not detected on 0, 6, and 7 days after feeding. Pathogenicity tests were conducted by transplanting eggplant plants into soil substrate amended with 20% decomposed manure, collected from the four animals fed with the infested forage. At 52 days after transplanting, manure-treated plants exhibited Verticillium wilt symptoms whereas, 2 months later, disease incidence, disease severity, and percentage of positive V. dahliae isolations from stem tissues were 58.3, 30.7, and 48.3%, respectively. Symptoms or positive isolations were not observed in control plants (transplanted in 100% soil substrate). This is the first report of the active role of V. dahliae passed through the digestive system of sheep as effective inoculum for host plants, in relation to the span persistence and transmission via the sheep carrier.