bluuebunny/crossref_metadata_2025 huggingface dataset:
A time dependent DFT study of the efficiency of polymers for organic photovoltaics at the interface with PCBM
Authors: Van den Brande N. , Van Lier G. , Da Pieve F. , Van Assche G. , Van Mele B. , De Proft F. , Geerlings P.
Published: October 2014

In this work an intuitive (TD-DFT) approach was developed to explain the experimental efficiencies seen for organic photovoltaic devices.
Tailored chondroitin sulfate glycomimetics via a tunable multivalent scaffold for potentiating NGF/TrkA-induced neurogenesis
Authors: Liu Pei , Chen Liwei , Toh Jerry K. C. , Ang Yi Li , Jee Joo-Eun , Lim Jaehong , Lee Su Seong , Lee Song-Gil
Published: October 2014

We have engineered structurally well-defined tunable chondroitin sulfate glycopeptides using a polyproline scaffold to selectively modulate the NGF-mediated neuronal signaling pathway.
Multiplexed DNA detection based on positional encoding/decoding with self-assembled DNA nanostructures
Authors: Sun Sha , Yao Huaxin , Zhang Feifei , Zhu Jin
Published: October 2014

A multiplexed DNA detection strategy with fast hybridization kinetics based on positional encoding/decoding with self-assembled DNA nanostructures has been developed.
Annihilation electrogenerated chemiluminescence of mixed metal chelates in solution: modulating emission colour by manipulating the energetics
Authors: Kerr Emily , Doeven Egan H. , Barbante Gregory J. , Hogan Conor F. , Bower David J. , Donnelly Paul S. , Connell Timothy U. , Francis Paul S.
Published: October 2014

The emissions of the mixed annihilation ECL of metal complexes can be effectively predicted by estimations of reaction exergonicity.
Stepwise isolation of low-valent, low-coordinate Sn and Pb mono- and dications in the coordination sphere of platinum
Authors: Braunschweig Holger , Celik Mehmet Ali , Dewhurst Rian D. , Heid Magdalena , Hupp Florian , Sen Sakya S.
Published: October 2014

Halide groups are sequentially removed from platinum complexes containing tin and lead dihalide ligands, creating novel mono- and dicationic complexes.
Elasticity of 3D networks with rigid filaments and compliant crosslinks
Authors: Heidemann Knut M. , Sharma Abhinav , Rehfeldt Florian , Schmidt Christoph F. , Wardetzky Max
Published: October 2014

We extract the elastic properties of 3D random networks of rigid filaments and compliant crosslinksviaphysical simulations, and derive asymptotic scaling relations of the elastic modulus with the stress in the context of an affine theory.
Hybrid acrylic/CeO2nanocomposites using hydrophilic, spherical and high aspect ratio CeO2nanoparticles
Authors: Aguirre Miren , Johansson Salazar-Sandoval Eric , Johansson Mats , Ahniyaz Anwar , Paulis Maria , Leiza Jose Ramon
Published: October 2014

High aspect ratio CeO2nanoparticles have been incorporated into waterborne acrylic polymer hybrids for the first time.
Aqueous Li-ion cells with superior cycling performance using multi-channeled polyaniline/Fe2O3 nanotube anodes
Authors: Wang Yuhang , Wang Yehua , Tang Jing , Xia Yongyao , Zheng Gengfeng
Published: October 2014

A Fe2O3-decorated polyaniline multi-channeled nanotube structure is synthesized for aqueous rechargeable lithium-ion battery anode with superior cycling performance.
Aluminum–air battery based on an ionic liquid electrolyte
Authors: Gelman D. , Shvartsev B. , Ein-Eli Y.
Published: October 2014

This study presents a novel non-aqueous Al–air battery utilizing 1-ethyl-3-methylimidazolium oligo-fluoro-hydrogenate room temperature ionic liquid. The Al–air-RTIL system can sustain current densities up to 1.5 mA cm−2, producing capacities above 140 mA h cm−2, thus utilizing above 70% of the theoretical Al capacity.
Supported platinum–zinc oxide core–shell nanoparticle catalysts for methanol steam reforming
Authors: Arroyo-Ramírez Lisandra , Chen Chen , Cargnello Matteo , Murray Christopher B. , Fornasiero Paolo , Gorte Raymond J.
Published: October 2014

Pt@ZnO and Pd@ZnO core–shell structures have been synthesized and shown to form alloy catalysts with good CO2 selectivity for MSR.
NiO nanorod array anchored Ni foam as a binder-free anode for high-rate lithium ion batteries
Authors: Yang Wanfeng , Cheng Guanhua , Dong Chaoqun , Bai Qingguo , Chen Xiaoting , Peng Zhangquan , Zhang Zhonghua
Published: October 2014

3D binder-free NiO nanorod-anchored Ni foam electrodes synthesized by in situ anodization and annealing exhibit superior cyclability and high rate performance.
Didanosine-loaded poly(epsilon-caprolactone) microparticles by a coaxial electrohydrodynamic atomization (CEHDA) technique
Authors: Seremeta Katia P. , Höcht Christian , Taira Carlos , Cortez Tornello Pablo R. , Abraham Gustavo A. , Sosnik Alejandro
Published: October 2014

EHDA technology was used to encapsulate the water-soluble antiretroviral ddI within PCL particles and stabilize it in the gastric medium where it undergoes fast degradation.
Functionalized carbon dots enable simultaneous bone crack detection and drug deposition
Authors: Krishna A. Shanti , Radhakumary C. , Antony Molly , Sreenivasan K.
Published: October 2014

Decorated carbon dots enable simultaneous bone crack viewing and drug deposition.
In vitro and in vivo gene transfection using biodegradable and low cytotoxic nanomicelles based on dendritic block copolymers
Authors: Liu Yan , Lin Chao , Li Jianbo , Qu Yang , Ren Jie
Published: October 2014

Dendritic PCL-b-PDMAEMA copolymers have been used as non-viral vectors for gene transfection and exhibited high transfection efficiencies and low cytotoxicity.
Metal chelate grafting at the surface of mesoporous silica nanoparticles (MSNs): physico-chemical and biomedical imaging assessment
Authors: Laprise-Pelletier Myriam , Bouchoucha Meryem , Lagueux Jean , Chevallier Pascale , Lecomte Roger , Gossuin Yves , Kleitz Freddy , Fortin Marc-André
Published: October 2014

A physico-chemical characterization and dual in vivo imaging (PET/MRI) of MSNs functionalized with DTPA and labeled with Gd3+ and 64Cu2+.
Improving the bit error rate performance by optimising energy allocation based on union bound
Authors: Xia Shao , Weidang Zhang , Ping Li
Published: October 2014

A new method to improve the bit error rate (BER) performance by optimising the bit energy is proposed in this study. This method is mainly based on a formula derived from the union bound that can estimate the BER for every bit in the codeword sequence. Then by mathematical optimisation and assisted with a BER distribution, the energy for every bit can be optimised so that the average BER achieves the minimum value. Compared with other methods, this method considering all the codewords with minimum Hamming weights and their multiplicity to each bit of the codewords. The simulation examples show that the average BER is improved not only at high signal‐to‐noise ratio (SNR), but also at low and moderate SNRs.
QoS‐based device‐to‐device communication schemes in heterogeneous wireless networks
Authors: Dai Zeyang , Liu Jian , Wang Chonggang
Published: October 2014

This study considers spectrum sharing problems in the heterogeneous wireless networks where different device‐to‐device (D2D) users coexist with the cellular users. The authors propose a novel scheme, called ‘spectrum partition‐based D2D transmission’ (SPDT), to improve spectrum efficiency of the D2D and cellular networks. In SPDT, the D2D users assist the cellular transmissions to gain some spectrum released from the cellular system. Then, the obtained spectrum is divided into several frequency bands and each band is assigned to a different D2D pair for its data transmission. Under the quality‐of‐service (QoS) constraints of both the D2D and cellular users, the authors exploit the tradeoff in the power allocation of the D2D transmitters and show that the number of the allowed accessing D2D pairs can be maximised by optimising the D2D transmitters power for SPDT. For comparison the power optimisation problem is also investigated with the objective of maximising the number of allowed users accessing D2D pairs in the power control scheme, called ‘underlay D2D transmission’ (UDT). This is where the D2D users access the spectrum being used by the cellular users with power control while ensuring that the QoS of the cellular transmissions is satisfied. Finally, the simulation results show evident performance gains of the proposed SPDT scheme over the UDT scheme.
Posture regulation for unicycle‐like robots with prescribed performance guarantees
Authors: Zambelli Martina , Karayiannidis Yiannis , Dimarogonas Dimos V.
Published: October 2014

This study aims to address the regulation problem for the unicycle model while guaranteeing prescribed performance. Different controllers based either on polar coordinates or time‐varying laws are proposed. The main contribution is the combination of the standard control laws that allow to achieve posture regulation for the unicycle, with the prescribed performance control technique that imposes time‐varying constraints to the system coordinates. To apply prescribed performance to the unicycle system which is subject to a non‐holonomic constraint, the authors design a specific transformation function that is instrumental in the proof of asymptotic convergence with prescribed guaranties.
Data‐driven design of two‐degree‐of‐freedom controllers using reinforcement learning techniques
Authors: Zhang Yong , Ding Steven X. , Yang Ying , Li Linlin
Published: October 2014

Motivated by the successful application for feedback control, this study extends the study of reinforcement learning techniques to the design of two‐degree‐of‐freedom controllers in the data‐driven environment. Based on the residual generator based form of Youla parameterisation, all stabilising controllers are first interpreted in the feedback–feedforward situation with a Kalman filter‐based residual generator acting as the core part. For the reference tracking problem, further discussions are conducted from the regulatory perspective and using the Q learning, recursive least squares methods and the policy iteration algorithm. The entire design is carried out as a two‐stage process that separately achieves the optimal feedback and feedforward controllers. Finally, the effectiveness of the proposed approach is demonstrated with its application in the laboratory continuous stirred tank heater process.
Non‐fragile mixed ℋ∞ /l2  − l∞ synchronisation control for complex networks with Markov jumping‐switching topology under unreliable communication links
Authors: Shen Hao , Wu Zheng‐Guang , Zhang Zhengqiang , Park Ju H.
Published: October 2014

This study is concerned with the non‐fragile mixed ℋ∞ /l2  − l∞ synchronisation control problem for discrete‐time complex networks with Markov jumping‐switching topology under unreliable communication links. The network topology under consideration is assumed to be governed by a Markov chain with time‐varying transition probabilities (TPs). The variation of TPs is subject to a kind of slow switching signals; that is, the average dwell time (ADT) switching. The focus is on the design of non‐fragile mixed mode‐dependent/‐independent controllers such that the underlying network reaches stochastic mean‐square synchronisation with a mixed ℋ∞ /l2  − l∞ performance level for an admissible switching signal with ADT. By using a new mixed ℋ∞ /l2  − l∞ performance index, combined with the switched control method, the solutions to the considered problem are formulated. Finally, simulation results demonstrate the effectiveness of our proposed approach.
Networked predictive control for systems with unknown or partially known delay
Authors: Sun Jian , Chen Jie
Published: October 2014

This study is concerned with the problem of controller design for linear systems with unknown or partially known communication delay. A new networked predictive control scheme is proposed to deal with the unknown or partially known communication delay. The closed‐loop system is modelled as a switched system under constraint switching taking an important property of communication delay into account. Sufficient stability conditions are derived using switched Lyapunov function approach. On the basis of stability conditions, the method of designing the controller gain matrix and some important parameters in the control scheme is investigated. Finally, a numerical example is given to confirm the effectiveness of the proposed method.
A multi‐agent coordinated planning approach for deadline required emergency response tasks
Authors: Zhou Chao , Wang Hongwei , Zhuo Hankz Hankui
Published: October 2014

This study investigates the emergency decision‐making problem in a multi‐agent system. Departments are modeled as agents to perform coordinated planning to obtain a global action plan with a short execution time constrained by a prescribed deadline. A novel multi‐agent planning approach is proposed to coordinate for the solution among agents in the system. The approach consists of two stages. For the first stage, a coordinated planning and scheduling method is designed to generate a candidate global action plan. In this plan, durative actions are assigned to proper time intervals with the consideration of temporal relationships among agents. For the second stage, a coordination mechanism based on local heuristics is proposed to reduce the global time cost of the candidate plan to satisfy the deadline. An experimental study of emergency evacuation problem is conducted to demonstrate the effectiveness and efficiency of the proposed approach.
Patch‐based locality‐enhanced collaborative representation for face recognition
Authors: Ding Ru‐Xi , Huang He , Shang Jin
Published: October 2014

In the field of face recognition, the small sample size (SSS) problem and non‐ideal situations of facial images are recognised as two of the most challenging issues. Recently, Zhu et al. proposed a patch‐based collaborative representation (PCRC) method which showed good performance for the SSS and the single sample per person problems; and Peng et al. proposed a locality‐constrained collaborative representation (LCCR) method which achieved high robustness for face recognition in non‐ideal situations. Inspired by the methods proposed in PCRC and LCCR, this study proposes a patch‐based locality‐enhanced collaborative representation (PLECR) method to combine and enhance the advantages of both PCRC and LCCR. The PLECR and several related methods are implemented on AR, face recognition technology and extended Yale B databases; and the extensive numerical results show that PLECR is more efficient among these methods for the SSS problem in non‐ideal situations, especially for the SSS problem with occlusions.
Fast large‐scale image enlargement method with a novel evaluation approach: benchmark function‐based peak signal‐to‐noise ratio
Authors: Guo Shu‐Mei , Hsu Chih‐Yuan , Kuo Gia‐Hao , Tsai Jason Sheng‐Hong
Published: October 2014

An objective novel evaluation approach, implemented by the benchmark function‐based peak signal‐to‐noise ratio, particularly suitable for evaluating the performance of a large‐scale enlargement of a small size image is proposed in this study. Also, a fast large‐scale image enlargement method via the improved discrete cosine transform (DCT) is proposed to improve the quality and speed of image zooming. The proposed image enlargement algorithm based on DCT saves computation time by multiplication of the DCT matrix. Compared with the traditional DCT approach, the improved approach overcomes the image shifting and blocky effects. In comparisons with other interpolation methods, DCT enlargement outperforms them in edge details because it considers the global frequency information of the whole image. With the DCT enlargement, it is easy to implement the arbitrary pixel‐size‐based zooming of an image by employing the different size of transform matrix. Illustrative examples show the effectiveness of the proposed approach.
Acquisition source identification through a blind image classification
Authors: Amerini Irene , Becarelli Rudy , Bertini Bruno , Caldelli Roberto
Published: October 2014

Image forensics, besides understanding if a digital image has been forged, often aims at determining information about image origin. In particular, it could be worthy to individuate which is the kind of source (digital camera, scanner or computer graphics software) that has generated a certain photo. Such an issue has already been studied in literature, but the problem of doing that in a blind manner has not been faced so far. It is easy to understand that in many application scenarios information at disposal is usually very limited; this is the case when, given a set of L images, the authors want to establish if they belong to K different classes of acquisition sources, without having any previous knowledge about the number of specific types of generation processes. The proposed system is able, in an unsupervised and fast manner, to blindly classify a group of photos without neither any initial information about their membership nor by resorting at a trained classifier. Experimental results have been carried out to verify actual performances of the proposed methodology and a comparative analysis with two SVM‐based clustering techniques has been performed too.
Investigation of the effects of homogeneous and heterogeneous solar irradiations on multicrystal PV module under various configurations
Authors: Pon Vengatesh R. , Edward Rajan S.
Published: October 2014

This research work investigates the power‐voltage (P‐V) and current‐voltage (I‐V) characteristics of multicrystal photovoltaic (PV) module, connected in series, parallel and series‐parallel configurations. The modular characteristics of PV module have been performed under homogeneous and heterogeneous conditions. The experimental and simulation results indicate that for a given number of PV modules, the array configurations affect the maximum available output power and more local maxima are found under partially shaded conditions. The analysis of bypass diodes effect has been carried out under partial shadings on the PV module strings. The obtained results reveal that, the presence of bypass diodes allow the unshaded modules of all the series assemblies to conduct their maximum currents at a given solar radiation and temperature. Moreover, the comparative analysis of PV module has been carried out for different configurations under the above disturbances. Maximum output power is obtained, when PV modules are configured parallelly, even under shading conditions. The specifications of the PV module have been obtained from the manufacturer datasheet (KC200GT) for these investigations.
Analytical model of electron transport in polycrystalline, degenerately doped ZnO films
Authors: Bikowski André , Ellmer Klaus
Published: October 2014

An analytical description of the charge carrier transport, valid for non-degenerated and degenerated semiconductors, was developed, critically reviewed, and fitted to the temperature-dependent Hall mobility data of magnetron sputtered, degenerately doped ZnO:Al films. Our extended model for grain boundary scattering in semiconductors of arbitrary degeneracy is based on previous models from literature and suitable to describe the Hall mobility of the carriers as a function of the free carrier concentration and the temperature at the same time. It is mathematically simple enough for a fast fit procedure, which is not possible with most of the previous models. Applying a combined transport model consisting of ionized impurity scattering, phonon scattering, and grain boundary scattering in degenerate semiconductors, we were able to determine the trap density at the grain boundaries Nt ≈ 3 × 1013 to 5 × 1013 cm−2 and the deformation potential Eac in the range of 5 eV to 9 eV depending on the details of the transport model.
Tuning gain and bandwidth of traveling wave tubes using metamaterial beam-wave interaction structures
Authors: Lipton Robert , Polizzi Anthony
Published: October 2014

We employ metamaterial beam-wave interaction structures for tuning the gain and bandwidth of short traveling wave tubes. The interaction structures are made from metal rings of uniform cross section, which are periodically deployed along the length of the traveling wave tube. The aspect ratio of the ring cross sections is adjusted to control both gain and bandwidth. The frequency of operation is controlled by the filling fraction of the ring cross section with respect to the size of the period cell.
Observation of a new electronic state of CO perturbing $\bm {W\,{}^1\Pi (v=1)}$WΠ1(v=1)
Authors: Heays A. N. , Eidelsberg M. , Stark G. , Lemaire J. L. , Gavilan L. , Federman S. R. , Lewis B. R. , Lyons J. R. , de Oliveira N. , Joyeux D.
Published: October 2014

We observe photoabsorption of the W(1) ← X(0) band in five carbon monoxide isotopologues with a vacuum-ultraviolet Fourier-transform spectrometer and a synchrotron radiation source. We deduce transition energies, integrated cross sections, and natural linewidths of the observed rotational transitions and find a perturbation affecting these. Following a deperturbation analysis of all five isotopologues, the perturbing state is assigned to the v = 0 level of a previously unobserved 1Π state predicted by ab initio calculations to occur with the correct symmetry and equilibrium internuclear distance. We label this new state E″ 1Π. Both of the interacting levels W(1) and E″(0) are predissociated, leading to dramatic interference effects in their corresponding linewidths.
Defect density and dielectric constant in perovskite solar cells
Authors: Samiee Mehran , Konduri Siva , Ganapathy Balaji , Kottokkaran Ranjith , Abbas Hisham A. , Kitahara Andrew , Joshi Pranav , Zhang Liang , Noack Max , Dalal Vikram
Published: October 2014

We report on measurement of dielectric constant, mid-gap defect density, Urbach energy of tail states in CH3NH3PbIxCl1−x perovskite solar cells. Midgap defect densities were estimated by measuring capacitance vs. frequency at different temperatures and show two peaks, one at 0.66 eV below the conduction band and one at 0.24 eV below the conduction band. The attempt to escape frequency is in the range of 2 × 1011/s. Quantum efficiency data indicate a bandgap of 1.58 eV. Urbach energies of valence and conduction band are estimated to be ∼16 and ∼18 meV. Measurement of saturation capacitance indicates that the relative dielectric constant is ∼18.
Numerical matching of the sheath and presheath solutions for a spherical probe in radial-motion theory
Authors: Din Alif , Kuhn Siegbert
Published: October 2014

The theory of positive-ion collection by a probe immersed in a low-pressure plasma was reviewed and extended by Allen, Boyd, and Reynolds [Proc. Phys. Soc. 70, 297 (1957)]. For a given value of the ion current, the boundary values of the matched “nonneutral” or “sheath” solution Ṽnn(m)(r; rm) were obtained from the “quasineutral” or “presheath” solution Ṽqn(r) by choosing the small potential and electric-field values corresponding to some large “matching radius” rm. Here, a straightforward but efficient numerical method is presented for systematically determining an optimal value of the matching radius at which the presheath and sheath solutions are joined to yield the “matched” potential profile. Some suitable initial matching radius rm1 is chosen and the related potential and electric-field values of the quasineutral solution are calculated. Using these as boundary conditions, Poisson's equation is integrated to yield the matched nonneutral solution including the corresponding potential at the probe surface. This procedure is repeated for increasing values rm2, rm3,…. until the resulting potential at the probe surface becomes practically constant. The corresponding value of rm is taken as the “optimal” matching radius rmo at which the presheath and sheath solutions are ultimately joined to yield the “optimal” matched potential profile in the entire plasma-probe transition region. It is also shown that the Bohm criterion is inapplicable in the present problem.
Chaotic coordinates for the Large Helical Device
Authors: Hudson S. R. , Suzuki Y.
Published: October 2014

The theory of quadratic-flux-minimizing (QFM) surfaces is reviewed, and numerical techniques that allow high-order QFM surfaces to be efficiently constructed for experimentally relevant, non-integrable magnetic fields are described. As a practical example, the chaotic edge of the magnetic field in the Large Helical Device (LHD) is examined. A precise technique for finding the boundary surface is implemented, the hierarchy of partial barriers associated with the near-critical cantori is constructed, and a coordinate system, which we call chaotic coordinates, that is based on a selection of QFM surfaces is constructed that simplifies the description of the magnetic field, so that flux surfaces become “straight” and islands become “square.”
Piezoelectric voltage coupled reentrant cavity resonator
Authors: Carvalho N. C. , Fan Y. , Le Floch J-M. , Tobar M. E.
Published: October 2014

A piezoelectric voltage coupled microwave reentrant cavity has been developed. The central cavity post is bonded to a piezoelectric actuator allowing the voltage control of small post displacements over a high dynamic range. We show that such a cavity can be implemented as a voltage tunable resonator, a transducer for exciting and measuring mechanical modes of the structure, and a transducer for measuring comparative sensitivity of the piezoelectric material. Experiments were conducted at room and cryogenic temperatures with results verified using Finite Element software.
Magnetostatic modes in a uniform magnetic nanorod
Authors: Kasperski Maciej
Published: October 2014

We present a simple model which allows to describe a three-dimensional ferromagnetic nanorod placed in a strong external magnetic field as a one-dimensional chain of what we call superspins (a collection of pseudospins). Main properties like interaction energy, spatial inhomogeneity of magnetization, and ferromagnetic resonance frequency are reproduced with great accuracy. Within presented framework, we discuss the double ferromagnetic resonance occurring in nanostructures.
Electrostatic rogue-waves in relativistically degenerate plasmas
Authors: Akbari-Moghanjoughi M.
Published: October 2014

In this paper, we investigate the modulational instability and the possibility of electrostatic rogue-wave propagations in a completely degenerate plasma with arbitrary degree of degeneracy, i.e., relativistically degenerate plasma, ranging from solid density to the astrophysical compact stars. The hydrodynamic approach along with the perturbation method is used to reduce the governing equations to the nonlinear Schrödinger equation from which the modulational instability, the growth rate of envelope excitations and the occurrence of rogue as well as super-rogue waves in the plasma, is evaluated. It is observed that the modulational instability in a fully degenerate plasma can be quite sensitive to the plasma number-density and the wavenumber of envelop excitations. It is further revealed that the relativistically degeneracy plasmas (R0 > 1) are almost always modulationally unstable. It is found, however, that the highly energetic sharply localized electrostatic rogue as well as super-rogue waves can exist in the astrophysical compact objects like white dwarfs and neutron star crusts. The later may provide a link to understand many physical processes in such stars and it may lead us to the origin of the random-localized intense short gamma-ray bursts, which “appear from nowhere and disappear without a trace” quite similar to oceanic rogue structures.
Field-dependent perpendicular magnetic anisotropy in CoFeB thin films
Authors: Barsukov I. , Fu Yu , Gonçalves A. M. , Spasova M. , Farle M. , Sampaio L. C. , Arias R. E. , Krivorotov I. N.
Published: October 2014

We report ferromagnetic resonance measurements of perpendicular magnetic anisotropy in thin films of Ta/Co20Fe60B20/MgO as a function of the Co20Fe60B20 layer thickness. The first and second order anisotropy terms show unexpectedly strong dependence on the external magnetic field applied to the system during the measurements. We propose strong interfacial spin pinning as a possible origin of the field-dependent anisotropy. Our results imply that high-field anisotropy measurements cannot be directly used for quantitative evaluation of zero-field performance parameters of CoFeB-based devices such as spin torque memory.
Dynamics of the OH group and the electronic structure of liquid alcohols
Authors: Schreck Simon , Pietzsch Annette , Kunnus Kristjan , Kennedy Brian , Quevedo Wilson , Miedema Piter S. , Wernet Philippe , Föhlisch Alexander
Published: October 2014

In resonant inelastic soft x-ray scattering (RIXS) from molecular and liquid systems, the interplay of ground state structural and core-excited state dynamical contributions leads to complex spectral shapes that partially allow for ambiguous interpretations. In this work, we dissect these contributions in oxygen K-edge RIXS from liquid alcohols. We use the scattering into the electronic ground state as an accurate measure of nuclear dynamics in the intermediate core-excited state of the RIXS process. We determine the characteristic time in the core-excited state until nuclear dynamics give a measurable contribution to the RIXS spectral profiles to τdyn = 1.2 ± 0.8 fs. By detuning the excitation energy below the absorption resonance we reduce the effective scattering time below τdyn, and hence suppress these dynamical contributions to a minimum. From the corresponding RIXS spectra of liquid methanol, we retrieve the “dynamic-free” density of states and find that it is described solely by the electronic states of the free methanol molecule. From this and from the comparison of normal and deuterated methanol, we conclude that the split peak structure found in the lone-pair emission region at non-resonant excitation originates from dynamics in the O–H bond in the core-excited state. We find no evidence that this split peak feature is a signature of distinct ground state structural complexes in liquid methanol. However, we demonstrate how changes in the hydrogen bond coordination within the series of linear alcohols from methanol to hexanol affect the split peak structure in the liquid alcohols.
Native point defects in GaSb
Authors: Kujala J. , Segercrantz N. , Tuomisto F. , Slotte J.
Published: October 2014

We have applied positron annihilation spectroscopy to study native point defects in Te-doped n-type and nominally undoped p-type GaSb single crystals. The results show that the dominant vacancy defect trapping positrons in bulk GaSb is the gallium monovacancy. The temperature dependence of the average positron lifetime in both p- and n-type GaSb indicates that negative ion type defects with no associated open volume compete with the Ga vacancies. Based on comparison with theoretical predictions, these negative ions are identified as Ga antisites. The concentrations of these negatively charged defects exceed the Ga vacancy concentrations nearly by an order of magnitude. We conclude that the Ga antisite is the native defect responsible for p-type conductivity in GaSb single crystals.
Comparison of two- and three-dimensional simulations of miscible Richtmyer-Meshkov instability with multimode initial conditions
Authors: Olson Britton J. , Greenough Jeffrey A.
Published: October 2014

A comparison between two- and three-dimensional large-eddy simulations of the planar Richtmyer-Meshkov instability with multimode initial conditions is made. The three-dimensional calculation achieves a turbulent state where an inertial range of length scales is present after the second shock wave impacts the interface. Grid independence of the mixing width up until the time of reshock is demonstrated through mesh refinement in both two and three dimensions. Quantitative measures of mixing are compared including the mixing width, mixedness, mixed mass, and spectra of velocity and density. A proposed approximate relation for the mixed mass is evaluated in one, two, and three dimensions and is proportional to the product of the mixing width and the mass fraction variance in the layer. The variance of the velocity field and the scalar mass fraction are compared in two and three dimensions and demonstrate large differences in behavior.
Influence of an electric field on the spin-reorientation transition in Ni/Cu(100)
Authors: Gerhard Lukas , Bonell Frédéric , Wulfhekel Wulf , Suzuki Yoshishige
Published: October 2014

Magnetoelectric coupling offers the possibility to change the magnetic state of a material by an applied electric field. Over the last few years, metallic systems have come up as simple prototypes for this interaction. While the previous studies focused on Fe and Co thin films or their alloys, here we demonstrate magnetoelectric coupling in a Ni thin film which is close to a spin-reorientation transition. Our magneto-optic Kerr effect measurements on 10 ML of Ni/Cu(100) show a considerable influence of the applied electric field on the magnetism. This rounds off the range of magnetic metals that exhibit magnetoelectric coupling, and it reveals the possibility of an electric field control of a spin-reorientation transition.
Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt
Authors: Bai Yuanyuan , Chen Baohong , Xiang Feng , Zhou Jinxiong , Wang Hong , Suo Zhigang
Published: October 2014

Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.
Hydrothermal epitaxial growth and nonvolatile bipolar resistive switching behavior of LaFeO3-PbTiO3 films on Nb:SrTiO3(001) substrate
Authors: Zhang Peng , Gao Cunxu , Lv Fengzhen , Wei Yanping , Dong Chunhui , Jia Chenglong , Liu Qingfang , Xue Desheng
Published: October 2014

Epitaxial LaFeO3-PbTiO3 (LFPTO) thin films were hydrothermally grown on the Nb-SrTiO3 (100) (NSTO) substrates with a thickness about 250 nm. As fabricated Pt/LFPTO/NSTO/Pt devices exhibit reversible bipolar resistive switching behavior. The resistance ratios between high resistance state and low resistance state exceed three orders of magnitude, which can be maintained over 6 h without observable degradation. It indicates that the Pt/LFPTO/NSTO/Pt devices reveal excellent data retention and endurance characteristics. The resistive switching mechanism of the device could be attributed to the trap-controlled space-charge-limited current conduction which is controlled by the localized oxygen vacancies in the films. Furthermore, variation of Pt/LFPTO Schottky junction depletion thickness and barriers height modulated by oxygen vacancies at Pt/LFPTO interface was suggested to be responsible for the resistance switching behaviors of the devices.
Heterotrimeric G-proteins involved in the MeJA regulated ion flux and stomatal closure in Arabidopsis thaliana
Authors: Yan Suli , Luo Shuitian , Dong Shanshan , Zhang Ting , Sun Jingru , Wang Ningning , Yao Hongjun , Shen Yingbai
Published: October 2014

Heterotrimeric G-proteins play an important role in plant signalling pathways. The plant hormone methyl jasmonate (MeJA) can induce stomatal closure in many plant species. The signal cascade in MeJA-induced stomatal closure has been studied previously. However, the function of G proteins in this process has not yet been evaluated. In this study, the stomatal movement induced by MeJA in the wild-type Arabidopsis thaliana (L. Heynh.) (WS), Gα subunit loss-of-function mutant gpa1–1 and gpa1–2 guard cells were measured. Further, the transmembrane ion flux (H+, Ca2+ and K+) and reactive oxygen species (ROS) experiments were performed in guard cells from WS, GDP-β-S pre-treated WS, gpa1–1 and gpa1–2 using non-invasive micro-test technique (NMT) and confocal technique. It was observed that the MeJA-induced stomatal closure was abolished in guard cells of gpa1 mutants. GDP-β-S pre-treatment and gpa1 mutants impaired the MeJA-activated H+ efflux, Ca2+ influx and K+ efflux. The accumulation of ROS in gpa1–1 and gpa1–2 guard cells was also lower than that in WS guard cells under MeJA treatment. These results suggested that Gα subunits are involved in regulating the signal events in JA signal pathway and stomatal closure.
Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes
Authors: Pratt Ashley J. , Shin David S. , Merz Gregory E. , Rambo Robert P. , Lancaster W. Andrew , Dyer Kevin N. , Borbat Peter P. , Poole Farris L. , Adams Michael W. W. , Freed Jack H. , Crane Brian R. , Tainer John A. , Getzoff Elizabeth D.
Published: October 2014

Significance

Mutations in human Cu, Zn superoxide dismutase (SOD) cause the motor neuron disease ALS. To better understand why, we compared the aggregation, metal binding, and conformational dynamics of normal and mutant SOD proteins by using the biophysical techniques of X-ray scattering, inductively coupled plasma MS, and ESR spectroscopy. For SOD proteins with defects at a mutational hotspot, we found that copper deficiency, flexibility, and aggregation paralleled clinical severity in ALS patients. These data support a unifying protein framework destabilization mechanism for SOD-linked ALS and thereby point to potential therapies for this lethal condition with few treatment options.
Functional improvements in β-lactoglobulin by conjugating with soybean soluble polysaccharide
Authors: Inada Naoki , Hayashi Mai , Yoshida Tadashi , Hattori Makoto
Published: October 2014

Soybean soluble polysaccharide (SSPS) was hydrolyzed by autoclaving for 6 and 12 h to obtain SSPS (6 h) and SSPS (12 h). Bovine β-lactoglobulin (BLG) was conjugated with each SSPS by the Maillard reaction to improve its function. Conjugation between BLG and each SSPS was confirmed by Sodium dodecyl sulfate polyacrylamide gel electrophoresis and isoelectric focusing. BLG-SSPS (6 h) and BLG-SSPS (12 h), respectively, retained approximately 56 and 43% of the retinol-binding activity of BLG. Structural analyses by intrinsic fluorescence and enzyme-linked immunosorbent assay with monoclonal antibodies indicated that the native structure of BLG had almost been maintained in each conjugate and that the surface structure was covered by conjugated SSPS. The emulsifying properties of BLG were improved in each conjugate at pH 3, 5, and 7 in the presence of 0.2 M NaCl. The antibody responses to BLG-SSPS (6 h) and BLG-SSPS (12 h) were considerably reduced in BALB/c mice. We conclude that conjugation with SSPS was very effective for improving the function of BLG and this study would contribute to greater utilization of SSPS.
Novel function discovery with GeneMANIA: a new integrated resource for gene function prediction in
Escherichia coli
Authors: Vlasblom James , Zuberi Khalid , Rodriguez Harold , Arnold Roland , Gagarinova Alla , Deineko Viktor , Kumar Ashwani , Leung Elisa , Rizzolo Kamran , Samanfar Bahram , Chang Luke , Phanse Sadhna , Golshani Ashkan , Greenblatt Jack F. , Houry Walid A. , Emili Andrew , Morris Quaid , Bader Gary , Babu Mohan
Published: October 2014

Motivation: The model bacterium Escherichia coli is among the best studied prokaryotes, yet nearly half of its proteins are still of unknown biological function. This is despite a wealth of available large-scale physical and genetic interaction data. To address this, we extended the GeneMANIA function prediction web application developed for model eukaryotes to support E.coli .

Results: We integrated 48 distinct E.coli functional interaction datasets and used the GeneMANIA algorithm to produce thousands of novel functional predictions and prioritize genes for further functional assays. Our analysis achieved cross-validation performance comparable to that reported for eukaryotic model organisms, and revealed new functions for previously uncharacterized genes in specific bioprocesses, including components required for cell adhesion, iron–sulphur complex assembly and ribosome biogenesis. The GeneMANIA approach for network-based function prediction provides an innovative new tool for probing mechanisms underlying bacterial bioprocesses.

Contact:  gary.bader@utoronto.ca ; mohan.babu@uregina.ca

Supplementary information:  Supplementary data are available at Bioinformatics online.
Formation of an embryonic supermassive star in the first galaxy
Authors: Inayoshi Kohei , Omukai Kazuyuki , Tasker Elizabeth
Published: October 2014

We studied the gravitational collapse of a warm (∼8000 K) primordial-gas cloud as a candidate progenitor for a supermassive star (SMS; ≳ 105 M⊙) using a three-dimensional hydrodynamical simulation including all the relevant cooling processes of both H2 and H, which can potentially induce cloud fragmentation. This is the first simulation of this kind to resolve protostar formation. We find that from a weakly turbulent initial condition, the cloud undergoes runaway collapse without a major episode of fragmentation. Although the H2 fraction jumps by a large factor via the three-body reaction at ∼10−13 g cm−3, its cooling remains inefficient due to the optical thickness, and the temperature remains ≳ 3000 K. When the central core of the cloud becomes opaque to continuum radiation at ∼10−8 g cm−3, a hydrostatic protostar with ≃0.2 M⊙ is formed. The protostar grows to the mass ≃1 M⊙ and the radius ≃2 au within ∼1 yr via rapid accretion of dense filamentary flows. With high accretion rate, ∼2 M⊙ yr−1, the protostar is expected to turn into an SMS within its lifetime, eventually collapsing to a seed for the supermassive black hole observed in the early Universe at z ∼ 7.
A Role of AREB in the Regulation of PACC-Dependent Acid-Expressed-Genes and Pathogenicity of Colletotrichum gloeosporioides
Authors: Ment Dana , Alkan Noam , Luria Neta , Bi Fang-Cheng , Reuveni Eli , Fluhr Robert , Prusky Dov
Published: October 2014

Gene expression regulation by pH in filamentous fungi and yeasts is controlled by the PACC/RIM101 transcription factor. In Colletotrichum gloeosporioides, PACC is known to act as positive regulator of alkaline-expressed genes, and this regulation was shown to contribute to fungal pathogenicity. PACC is also a negative regulator of acid-expressed genes, however; the mechanism of downregulation of acid-expressed genes by PACC and their contribution to C. gloeosporioides pathogenicity is not well understood. RNA sequencing data analysis was employed to demonstrate that PACC transcription factor binding sites (TFBS) are significantly overrepresented in the promoter of PACC-upregulated, alkaline-expressed genes. In contrast, they are not overrepresented in the PACC-downregulated, acid-expressed genes. Instead, acid-expressed genes showed overrepresentation of AREB GATA TFBS in C. gloeosporioides and in homologs of five other ascomycetes genomes. The areB promoter contains PACC TFBS; its transcript was upregulated at pH 7 and repressed in ΔpacC. Furthermore, acid-expressed genes were found to be constitutively upregulated in ΔareB during alkalizing conditions. The areB mutants showed significantly reduced ammonia secretion and pathogenicity on tomato fruit. Present results indicate that PACC activates areB expression, thereby conditionally repressing acid-expressed genes and contributing critically to C. gloeosporioides pathogenicity.
Meta-Analysis Reveals a Critical Period for Management of Powdery Mildew on Hop Cones
Authors: Nelson Mark E. , Gent David H. , Grove Gary G.
Published: October 2014

Results of 28 field trials conducted over a 12-year period investigating management of hop powdery mildew caused by Podosphaera macularis were quantitatively summarized by meta-analysis to compare product efficacy and use patterns by mode of action as defined by Fungicide Resistance Action Committee (FRAC) groups. Availability of original observations enabled individual participant data meta-analysis. Differences in control of powdery mildew on leaves and cones were apparent among fungicide FRAC groups when individual products were evaluated over the course of a growing season. FRAC groups 13, 3, and U13 provided the most efficacious control of powdery mildew on leaves. Percent disease control on cones was influenced by midseason foliar disease and fungicide mode-of-action. FRAC 13 provided significantly better disease control on cones than all other groups except U13, 3, and premixes of 7 with 11. Disease control on leaves was similar when a rotational program of fungicides was used, independent of the modes of action, but improved on cones if FRAC groups 13 and 3 were both included compared with programs consisting of FRAC groups 11 and 3, 11 and 5, or 3 and 5. Disease control on cones was improved from 32 to 52%, on average, when the fungicide quinoxyfen (FRAC 13) was applied at least once during the early stages of cone development, defined in this analysis as 20 July to 10 August, as compared with all other treatments. Efficacy of disease control on cones by quinoxyfen was moderated by and interacted with the incidence of leaves with powdery mildew. Disease control on cones was further improved if two applications of quinoxyfen were made during this period. Collectively, these findings suggest that disease control during juvenile stages of cone development largely influences the success of fungicide programs and point to the critical importance of focusing management efforts during this stage of development, independent of what actual management strategy is employed.
Toward an Integrated Use of Biological Control by Cladosporium cladosporioides H39 in Apple Scab (Venturia inaequalis) Management
Authors: Köhl Jürgen , Scheer Christian , Holb Imre J. , Masny Sylwester , Molhoek Wilma
Published: October 2014

Apple scab, caused by Venturia inaequalis, is the most important disease in apple production, reducing yield and quality of fruit. Control of apple scab in commercial orchards currently depends on multiple applications of fungicides. The potential of the antagonistic isolate Cladosporium cladosporioides H39, originating from a sporulating colony of V. inaequalis, to control apple scab development was tested in eight trials during 2 years in orchards in Eperjeske (Hungary), Dabrowice (Poland), and Bavendorf (Germany) planted with different cultivars. Treatments were conducted as calendar sprays or after infection periods. Additional trials in an orchard in Randwijk (The Netherlands) focused on the effect of timing of antagonist application before or after infection periods. The overall results of the field trials consistently showed—for the first time—that stand-alone applications of the antagonist C. cladosporioides H39 can reduce apple scab in leaves and fruit. This was demonstrated in an organic growing system as well as in conventional orchards by spray schedules applied during the primary or the summer season. In both systems, the same control levels could be reached as with common fungicide schedules. Efficacies reached 42 to 98% on leaf scab incidence and 41 to 94% on fruit scab. The antagonist was also effective if applied one or even several days (equivalent to approximately 300 to 2,000 degree h) after infection events in several field trials and a trial conducted in Randwijk with single-spray applications at different intervals before or after infection events. Better understanding of the biology of the antagonist will help to further exploit its use in apple scab control.