bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell-secreted Flavins Bound to Membrane Cytochromes Dictate Electron Transfer Reactions to Surfaces with Diverse Charge and pH
Authors: Okamoto Akihiro , Kalathil Shafeer , Deng Xiao , Hashimoto Kazuhito , Nakamura Ryuhei , Nealson Kenneth H.
Published: July 2014

The variety of solid surfaces to and from which microbes can deliver electrons by extracellular electron transport (EET) processes via outer-membrane c-type cytochromes (OM c-Cyts) expands the importance of microbial respiration in natural environments and industrial applications. Here, we demonstrate that the bifurcated EET pathway of OM c-Cyts sustains the diversity of the EET surface in Shewanella oneidensis MR-1 via specific binding with cell-secreted flavin mononucleotide (FMN) and riboflavin (RF). Microbial current production and whole-cell differential pulse voltammetry revealed that RF and FMN enhance EET as bound cofactors in a similar manner. Conversely, FMN and RF were clearly differentiated in the EET enhancement by gene-deletion of OM c-Cyts and the dependency of the electrode potential and pH. These results indicate that RF and FMN have specific binding sites in OM c-Cyts and highlight the potential roles of these flavin-cytochrome complexes in controlling the rate of electron transfer to surfaces with diverse potential and pH.
Limits of Predictability in Commuting Flows in the Absence of Data for Calibration
Authors: Yang Yingxiang , Herrera Carlos , Eagle Nathan , González Marta C.
Published: July 2014

The estimation of commuting flows at different spatial scales is a fundamental problem for different areas of study. Many current methods rely on parameters requiring calibration from empirical trip volumes. Their values are often not generalizable to cases without calibration data. To solve this problem we develop a statistical expression to calculate commuting trips with a quantitative functional form to estimate the model parameter when empirical trip data is not available. We calculate commuting trip volumes at scales from within a city to an entire country, introducing a scaling parameter α to the recently proposed parameter free radiation model. The model requires only widely available population and facility density distributions. The parameter can be interpreted as the influence of the region scale and the degree of heterogeneity in the facility distribution. We explore in detail the scaling limitations of this problem, namely under which conditions the proposed model can be applied without trip data for calibration. On the other hand, when empirical trip data is available, we show that the proposed model's estimation accuracy is as good as other existing models. We validated the model in different regions in the U.S., then successfully applied it in three different countries.
Profiling of the Tox21 10K compound library for agonists and antagonists of the estrogen receptor alpha signaling pathway
Authors: Huang Ruili , Sakamuru Srilatha , Martin Matt T. , Reif David M. , Judson Richard S. , Houck Keith A. , Casey Warren , Hsieh Jui-Hua , Shockley Keith R. , Ceger Patricia , Fostel Jennifer , Witt Kristine L. , Tong Weida , Rotroff Daniel M. , Zhao Tongan , Shinn Paul , Simeonov Anton , Dix David J. , Austin Christopher P. , Kavlock Robert J. , Tice Raymond R. , Xia Menghang
Published: July 2014

The U.S. Tox21 program has screened a library of approximately 10,000 (10K) environmental chemicals and drugs in three independent runs for estrogen receptor alpha (ERα) agonist and antagonist activity using two types of ER reporter gene cell lines, one with an endogenous full length ERα (ER-luc; BG1 cell line) and the other with a transfected partial receptor consisting of the ligand binding domain (ER-bla; ERα β-lactamase cell line), in a quantitative high-throughput screening (qHTS) format. The ability of the two assays to correctly identify ERα agonists and antagonists was evaluated using a set of 39 reference compounds with known ERα activity. Although both assays demonstrated adequate (i.e. >80%) predictivity, the ER-luc assay was more sensitive and the ER-bla assay more specific. The qHTS assay results were compared with results from previously published ERα binding assay data and showed >80% consistency. Actives identified from both the ER-bla and ER-luc assays were analyzed for structure-activity relationships (SARs) revealing known and potentially novel ERα active structure classes. The results demonstrate the feasibility of qHTS to identify environmental chemicals with the potential to interact with the ERα signaling pathway and the two different assay formats improve the confidence in correctly identifying these chemicals.
A zirconium squarate metal–organic framework with modulator-dependent molecular sieving properties
Authors: Bueken Bart , Reinsch Helge , Reimer Nele , Stassen Ivo , Vermoortele Frederik , Ameloot Rob , Stock Norbert , Kirschhock Christine E. A. , De Vos Dirk
Published: July 2014

The guest uptake properties of a new squaric acid based zirconium metal–organic framework depend on the modulator used during synthesis.
Engineering β-lactamase zymogens for use in protease activity assays
Authors: Kim Hajin , Yoon Hyun Kyung , Yoo Tae Hyeon
Published: July 2014

In this report, we engineered β-lactamase zymogens and developed a sensitive protease assay method based on the precursor enzymes.
Two-color delay dependent IR probing of torsional isomerization in a [AgL1L2]+complex
Authors: Lang Johannes , Gaffga Maximilian , Menges Fabian , Niedner-Schatteburg Gereon
Published: July 2014

Two-color infrared multiple photon dissociation (2c-IR-MPD) spectroscopy with delayed pulses indicates a torsional isomerization in a “ligand–metal–chelate” complex [AgL1L2]+.
Cyclopentadienyl molybdenum alkyl ester complexes as catalyst precursors for olefin epoxidation
Authors: Grover Nidhi , Pöthig Alexander , Kühn Fritz E.
Published: July 2014

Piano-stool organomolybdenum complexes of formula [CpMo(CO)3(CHR2COOR1)] are described and applied for olefin epoxidation with tert-butyl hydroperoxide as an oxidant.
Beyond substrate analogues: new inhibitor chemotypes for glycosyltransferases
Authors: Tedaldi Lauren , Wagner Gerd K.
Published: July 2014

New inhibitor chemotypes for glycosyltransferases, which are not structurally derived from either donor or acceptor substrate, are being reviewed.
Photopolymerization of methyl methacrylate: effects of photochemical and photonic parameters on the chain length
Authors: Charlot V. , Ibrahim A. , Allonas X. , Croutxé-Barghorn C. , Delaite C.
Published: July 2014

The effects of photochemical and photonic parameters are investigated on the chain length of poly(methylmethacrylate) (PMMA) as formed by the free radical photopolymerization process.
Computational modelling of a graphene Fresnel lens on different substrates
Authors: Deng Sunan , Yetisen Ali K. , Jiang Kyle , Butt Haider
Published: July 2014

In this work we studied tunable lensing effects of graphene Fresnel lens on different substrates with incident light of 850 nm and 1550 nm wavelengths.
Polarization transfer solid-state NMR: a new method for studying cellulose dissolution
Authors: Gustavsson S. , Alves L. , Lindman B. , Topgaard D.
Published: July 2014

Detailed molecular-level information on dissolved and solid cellulose in aqueous dissolution media with ionic liquids by polarization transfer solid-state NMR.
Highly selective one-pot continuous synthesis of 2-methoxyethanol via hydrogenation of dimethyl oxalate on Cu/ZrO2 catalysts with balanced acid sites
Authors: Cui Yuanyuan , Wen Chao , Chen Xi , Dai Wei-Lin
Published: July 2014

The distribution of 2-methoxyethanol and ethylene glycol can be controlled by regulating the surface acidity of copper based zirconia catalysts for hydrogenation of dimethyl oxalate. The yield of 2-methoxyethanol can reach 68% due to the synergistic effect of the surface acid site and active copper site.
Multifunctional polymer composite with excellent shear stiffening performance and magnetorheological effect
Authors: Wang Sheng , Jiang Wanquan , Jiang Weifeng , Ye Fang , Mao Ya , Xuan Shouhu , Gong Xinglong
Published: July 2014

A novel multi-functional polymer composite with both excellent shear stiffening performance and magnetorheological effect has been synthesized.
Study on downlink spectral efficiency in orthogonal frequency division multiple access systems
Authors: Huo Qiang , Ma Meng , Jiao Bingli
Published: July 2014

In previous studies on the capacity of orthogonal frequency division multiple access (OFDMA) systems, it is usually assumed that co‐channel interference (CCI) from adjacent cells is a Gaussian‐distributed random variable. However, very‐little work shows that the Gaussian assumption does not hold true in OFDMA systems. In this study, the statistical property of CCI in downlink OFDMA systems is studied, and spectral efficiency of downlink OFDMA system is analysed based on the derived statistical model. First, the probability density function (PDF) of CCI in downlink OFDMA cellular systems is studied with the considerations of path loss, multipath fading and Gaussian‐like transmit signals. Moreover, some closed‐form expressions of the PDF are obtained for special cases. The derived results show that the PDFs of CCI are with a heavy tail, and significantly deviate from the Gaussian distribution. Then, based on the derived statistical properties of CCI, the downlink spectral efficiency is derived. Numerical and simulation results justify the derived statistical CCI model and spectral efficiency.
Localised discrete Fourier transform‐spread M‐ary amplitude shift keying orthogonal frequency division multiplexing with Hermitian symmetry for peak‐to‐average power ratio reduction
Authors: Sung Minkyu , Lee Jaehoon , Jeong Jichai
Published: July 2014

The authors propose a novel localised discrete Fourier transform (DFT) spread M‐ary amplitude shift keying (M‐ASK) orthogonal frequency division multiplexing (OFDM) system with the Hermitian symmetry (DFT‐spread M‐ASK HS OFDM) to reduce the peak‐to‐average power ratio (PAPR). Compared with the conventional OFDM and localised DFT‐spread OFDM, the proposed system has lower PAPR not only because of the DFT‐spread scheme but also its lower modulation order than other OFDM systems. The lower modulation order of the proposed system can be achieved by using the Hermitian symmetry of DFT. The simulation result shows that the localised DFT‐spread M‐ASK HS OFDM provides a significant improvement in bit‐error‐rate and reduced PAPR.
Going with the wind: temporal characteristics of potential wind curtailment in Ireland in 2020 and opportunities for demand response
Authors: McKenna Eoghan , Grünewald Philipp , Thomson Murray
Published: July 2014

The Republic of Ireland and Northern Ireland have ambitious targets for 40% of electricity to be supplied by renewables by 2020, with the majority expected to be supplied by wind power. There is, however, already a significant amount of wind power being turned down, or ‘curtailed’, and this is expected to grow as wind penetrations increase. A model‐based approach is taken to estimate curtailment using high‐resolution wind speed and demand data covering four years, with a particular focus on the temporal characteristics of curtailment and factors that affect it. The model is validated using actual wind output and curtailment data from 2011. The results for 2020 are consistent with previously published estimates, and indicate curtailment levels ranging from 5.6 to 8.5% depending on assumptions examined in this study. Curtailment is found to occur predominantly at night, and to exhibit stochastic variability related to wind output. To accommodate high penetrations of wind power, the findings highlight the value of flexible demand over relatively long time‐periods. The model's output data have been made publicly available for free for further investigation.
Magnetizability and rotational g tensors for density fitted local second-order Møller-Plesset perturbation theory using gauge-including atomic orbitals
Authors: Loibl Stefan , Schütz Martin
Published: July 2014

In this paper, we present theory and implementation of an efficient program for calculating magnetizabilities and rotational g tensors of closed-shell molecules at the level of local second-order Møller-Plesset perturbation theory (MP2) using London orbitals. Density fitting is employed to factorize the electron repulsion integrals with ordinary Gaussians as fitting functions. The presented program for the calculation of magnetizabilities and rotational g tensors is based on a previous implementation of NMR shielding tensors reported by S. Loibl and M. Schütz [J. Chem. Phys. 137, 084107 (2012)]. Extensive test calculations show (i) that the errors introduced by density fitting are negligible, and (ii) that the errors of the local approximation are still rather small, although larger than for nuclear magnetic resonance (NMR) shielding tensors. Electron correlation effects for magnetizabilities are tiny for most of the molecules considered here. MP2 appears to overestimate the correlation contribution of magnetizabilities such that it does not constitute an improvement over Hartree-Fock (when comparing to higher-order methods like CCSD(T)). For rotational g tensors the situation is different and MP2 provides a significant improvement in accuracy over Hartree-Fock. The computational performance of the new program was tested for two extended systems, the larger comprising about 2200 basis functions. It turns out that a magnetizability (or rotational g tensor) calculation takes about 1.5 times longer than a corresponding NMR shielding tensor calculation.
Bowl breakout: Escaping the positive region when searching for saddle points
Authors: Pedersen Andreas , Luiser Mathieu
Published: July 2014

We present a scheme improving the minimum-mode following method for finding first order saddle points by confining the displacements of atoms to the subset of those subject to the largest force. By doing so it is ensured that the displacement remains of a local character within regions where all eigenvalues of the Hessian matrix are positive. However, as soon as a region is entered where an eigenvalue turns negative all atoms are released to maintain the ability of determining concerted moves. Applying the proposed scheme reduces the required number of force calls for the determination of connected saddle points by a factor two or more compared to a free search. Furthermore, a wider distribution of the relevant low barrier saddle points is obtained. Finally, the dependency on the initial distortion and the applied maximal step size is reduced making minimum-mode guided searches both more robust and applicable.
Coarse-grained molecular simulations of membrane adhesion domains
Authors: Dharan Nadiv , Farago Oded
Published: July 2014

We use a coarse-grained molecular model of supported lipid bilayers to study the formation of adhesion domains. We find that this process is a first order phase transition, triggered by a combination of pairwise short range attractive interactions between the adhesion bonds and many-body Casimir-like interactions, mediated by the membrane thermal undulations. The simulation results display an excellent agreement with the recently proposed Weil-Farago two-dimensional lattice model, in which the occupied and empty sites represent, respectively, the adhesion bonds and unbound segments of the membrane. A second phase transition, into a hexatic phase, is observed when the attraction between the adhesion bonds is further strengthened.
Theoretical oxidation state analysis of Ru-(bpy)3: Influence of water solvation and Hubbard correction in first-principles calculations
Authors: Reeves Kyle G. , Kanai Yosuke
Published: July 2014

Oxidation state is a powerful concept that is widely used in chemistry and materials physics, although the concept itself is arguably ill-defined quantum mechanically. In this work, we present impartial comparison of four, well-recognized theoretical approaches based on Lowdin atomic orbital projection, Bader decomposition, maximally localized Wannier function, and occupation matrix diagonalization, for assessing how well transition metal oxidation states can be characterized. Here, we study a representative molecular complex, tris(bipyridine)ruthenium. We also consider the influence of water solvation through first-principles molecular dynamics as well as the improved electronic structure description for strongly correlated d-electrons by including Hubbard correction in density functional theory calculations.
Test of prototype ITER vacuum ultraviolet spectrometer and its application to impurity study in KSTAR plasmas
Authors: Seon C. R. , Hong J. H. , Jang J. , Lee S. H. , Choe W. , Lee H. H. , Cheon M. S. , Pak S. , Lee H. G. , Biel W. , Barnsley R.
Published: July 2014

To optimize the design of ITER vacuum ultraviolet (VUV) spectrometer, a prototype VUV spectrometer was developed. The sensitivity calibration curve of the spectrometer was calculated from the mirror reflectivity, the grating efficiency, and the detector efficiency. The calibration curve was consistent with the calibration points derived in the experiment using the calibrated hollow cathode lamp. For the application of the prototype ITER VUV spectrometer, the prototype spectrometer was installed at KSTAR, and various impurity emission lines could be measured. By analyzing about 100 shots, strong positive correlation between the O VI and the C IV emission intensities could be found.
Moments of the Gaussian β ensembles and the large-N expansion of the densities
Authors: Witte N. S. , Forrester P. J.
Published: July 2014

The loop equation formalism is used to compute the 1/N expansion of the resolvent for the Gaussian β ensemble up to and including the term at O(N−6). This allows the moments of the eigenvalue density to be computed up to and including the 12th power and the smoothed density to be expanded up to and including the term at O(N−6). The latter contain non-integrable singularities at the endpoints of the support—we show how to nonetheless make sense of the average of a sufficiently smooth linear statistic. At the special couplings β = 1, 2, and 4 there are characterisations of both the resolvent and the moments which allows for the corresponding expansions to be extended, in some recursive form at least, to arbitrary order. In this regard, we give fifth order linear differential equations for the density and resolvent at β = 1 and 4, which complements the known third order linear differential equations for these quantities at β = 2.
Brownian cluster dynamics with short range patchy interactions: Its application to polymers and step-growth polymerization
Authors: Prabhu A. , Babu S. B. , Dolado J. S. , Gimel J.-C.
Published: July 2014

We present a novel simulation technique derived from Brownian cluster dynamics used so far to study the isotropic colloidal aggregation. It now implements the classical Kern-Frenkel potential to describe patchy interactions between particles. This technique gives access to static properties, dynamics and kinetics of the system, even far from the equilibrium. Particle thermal motions are modeled using billions of independent small random translations and rotations, constrained by the excluded volume and the connectivity. This algorithm, applied to a single polymer chain leads to correct static and dynamic properties, in the framework where hydrodynamic interactions are ignored. By varying patch angles, various local chain flexibilities can be obtained. We have used this new algorithm to model step-growth polymerization under various solvent qualities. The polymerization reaction is modeled by an irreversible aggregation between patches while an isotropic finite square-well potential is superimposed to mimic the solvent quality. In bad solvent conditions, a competition between a phase separation (due to the isotropic interaction) and polymerization (due to patches) occurs. Surprisingly, an arrested network with a very peculiar structure appears. It is made of strands and nodes. Strands gather few stretched chains that dip into entangled globular nodes. These nodes act as reticulation points between the strands. The system is kinetically driven and we observe a trapped arrested structure. That demonstrates one of the strengths of this new simulation technique. It can give valuable insights about mechanisms that could be involved in the formation of stranded gels.
Realizing one-dimensional quantum and high-frequency transport features in aligned single-walled carbon nanotube ropes
Authors: Ncube Siphephile , Chimowa George , Chiguvare Zivayi , Bhattacharyya Somnath
Published: July 2014

The superiority of the electronic transport properties of single-walled carbon nanotube (SWNT) ropes over SWNT mats is verified from low temperature and frequency-dependent transport. The overall change of resistance versus in nanotube mats shows that 3D variable range hopping is the dominant conduction mechanism within the 2–300 K range. The magneto-resistance (MR) is found to be predominantly negative with a parabolic nature, which can also be described by the hopping model. Although the positive upturn of the MR at low temperatures establishes the contribution from quantum interference, the inherent quantum transport in individual tubes is suppressed at elevated temperatures. Therefore, to minimize multi-channel effects from inter-tube interactions and other defects, two-terminal devices were fabricated from aligned SWNT (extracted from a mat) for low temperature transport as well as high-frequency measurements. In contrast to the mat, the aligned ropes exhibit step-like features in the differential conductance within the 80–300 K temperature range. The effects of plasmon propagation, unique to one dimension, were identified in electronic transport as a non-universal power-law dependence of the differential conductance on temperature and source-drain voltage. The complex impedance showed high power transmission capabilities up to 65 GHz as well as oscillations in the frequency range up to 30 GHz. The measurements suggest that aligned SWNT ropes have a realistic potential for high-speed device applications.
Towards quantitative off-axis electron holographic mapping of the electric field around the tip of a sharp biased metallic needle
Authors: Beleggia M. , Kasama T. , Larson D. J. , Kelly T. F. , Dunin-Borkowski R. E. , Pozzi G.
Published: July 2014

We apply off-axis electron holography and Lorentz microscopy in the transmission electron microscope to map the electric field generated by a sharp biased metallic tip. A combination of experimental data and modelling provides quantitative information about the potential and the field around the tip. Close to the tip apex, we measure a maximum field intensity of 82 MV/m, corresponding to a field k factor of 2.5, in excellent agreement with theory. In order to verify the validity of the measurements, we use the inferred charge density distribution in the tip region to generate simulated phase maps and Fresnel (out-of-focus) images for comparison with experimental measurements. While the overall agreement is excellent, the simulations also highlight the presence of an unexpected astigmatic contribution to the intensity in a highly defocused Fresnel image, which is thought to result from the geometry of the applied field.
Disorder-driven spin-reorientation in multiferroic h-YMn1−xFexO3
Authors: Namdeo Sonu , Rao S. S. , Kaushik S. D. , Siruguri V. , Awasthi A. M.
Published: July 2014

Magnetic structure evolution of multiferroic hexagonal YMn1−xFexO3 (x = 0, 0.05, and 0.1) has been studied by carrying out detailed temperature-dependent neutron diffraction at zero and 5 T fields. Thermodynamic data confirm antiferromagnetic ordering at TN in all the compositions. Our sub-TN neutron diffraction results assign the magnetic structure of pure YMnO3 to Γ1 irreducible representation. Over the perturbative-doping range, magnetic structure changes via Γ1 + Γ2 for YMn0.95Fe0.05O3 on to Γ2 for YMn0.9Fe0.1O3, as the maiden compositional analogue of spin-reorientation; its occurrence in temperature-domain already reported for several manganites. Moreover, while the large thermal isostructural changes observed above TN are subdued in the ordered state, small alterations by the applied 5 T-field are relatively uniform across, confirming strong magneto-elastic nature of the system. Decrease of the ordered magnetic moment (μord) and planar magnetic frustration noted with Fe-doping is enhanced by the applied field, apparently through canting.
Proposal of high efficiency solar cells with closely stacked InAs/In0.48Ga0.52P quantum dot superlattices: Analysis of polarized absorption characteristics via intermediate–band
Authors: Yoshikawa H. , Kotani T. , Kuzumoto Y. , Izumi M. , Tomomura Y. , Hamaguchi C.
Published: July 2014

We present a theoretical study of the electronic structures and polarized absorption properties of quantum dot superlattices (QDSLs) using wide–gap matrix material, InAs/In0.48Ga0.52P QDSLs, for realizing intermediate–band solar cells (IBSCs) with two–step photon–absorption. The plane–wave expanded Burt–Foreman operator ordered 8–band k·p theory is used for this calculation, where strain effect and piezoelectric effect are taken into account. We find that the absorption spectra of the second transitions of two–step photon–absorption can be shifted to higher energy region by using In0.48Ga0.52P, which is lattice–matched material to GaAs substrate, as a matrix material instead of GaAs. We also find that the transverse magnetic polarized absorption spectra in InAs/In0.48Ga0.52P QDSL with a separate IB from the rest of the conduction minibands can be shifted to higher energy region by decreasing the QD height. As a result, the second transitions of two–step photon–absorption by the sunlight occur efficiently. These results indicate that InAs/In0.48Ga0.52P QDSLs are suitable material combination of IBSCs toward the realization of ultrahigh efficiency solar cells.
Iron-boron pairing kinetics in illuminated p-type and in boron/phosphorus co-doped n-type silicon
Authors: Möller Christian , Bartel Til , Gibaja Fabien , Lauer Kevin
Published: July 2014

Iron-boron (FeB) pairing is observed in the n-type region of a boron and phosphorus co-doped silicon sample which is unexpected from the FeB pair model of Kimerling and Benton. To explain the experimental data, the existing FeB pair model is extended by taking into account the electronic capture and emission rates at the interstitial iron (Fei) trap level as a function of the charge carrier densities. According to this model, the charge state of the Fei may be charged in n-type making FeB association possible. Further, FeB pair formation during illumination in p-type silicon is investigated. This permits the determination of the charge carrier density dependent FeB dissociation rate and in consequence allows to determine the acceptor concentration in the co-doped n-type silicon by lifetime measurement.
Magnetic properties of Mn3O4 film with a coexistence of two preferential orientations
Authors: Ren Lizhu , Zhou Wenqi , Wang Yunjia , Meng Meng , Wu Shuxiang , Li Shuwei
Published: July 2014

A Mn3O4 film with a coexistence of two preferential orientations has been grown on a Pt(111)//Si(100) substrate by plasma-assisted molecular beam epitaxy. The structural characteristics and chemical compositions of the film are investigated by using X-ray diffraction, Raman, and X-ray photoelectron spectra in detail. Together with the magnetic tests, the film is demonstrated to be a polycrystalline hausmannite Mn3O4 with no other impurities. Moreover, the hysteresis loops of the film are found to display a step or a characteristic shrinking at low fields. On the other hand, similar magnetic characteristics have also been discovered on the film with two phases grown on a MgAl2O4(001) substrate. In our opinion, considering the large magnetocrystalline anisotropy and shape anisotropy of the single crystal Mn3O4 film reported in previous works, the special structures and phases of the two films result in both of them as soft+hard magnetic composites, in agreement with some other reports.
The onset of ion heating during magnetic reconnection with a strong guide field
Authors: Drake J. F. , Swisdak M.
Published: July 2014

The onset of the acceleration of ions during magnetic reconnection is explored via particle-in-cell simulations in the limit of a strong ambient guide field that self-consistently and simultaneously follow the motions of protons and α particles. Heating parallel to the local magnetic field during reconnection with a guide field is strongly reduced compared with the reconnection of anti-parallel magnetic fields. The dominant heating of thermal ions during guide field reconnection results from pickup behavior of ions during their entry into reconnection exhausts and dominantly produces heating perpendicular rather than parallel to the local magnetic field. Pickup behavior requires that the ion transit time across the exhaust boundary (with a transverse scale of the order of the ion sound Larmor radius) be short compared with the ion cyclotron period. This translates into a threshold in the strength of reconnecting magnetic field that favors the heating of ions with high mass-to-charge. A simulation with a broad initial current layer produces a reconnecting system in which the amplitude of the reconnecting magnetic field just upstream of the dissipation region increases with time as reconnection proceeds. The sharp onset of perpendicular heating when the pickup threshold is crossed is documented. A comparison of the time variation of the parallel and perpendicular ion heating with that predicted based on the strength of the reconnecting field establishes the scaling of ion heating with ambient parameters both below and above the pickup threshold. The relevance to observations of ion heating in the solar corona is discussed.
Conditions for reflection and transmission of an ion acoustic soliton in a dusty plasma with variable charge dust
Authors: Malik Hitendra K. , Tomar Renu , Dahiya Raj P.
Published: July 2014

Modified Korteweg-de Vries (mKdV) equations are derived for the incident, reflected, and transmitted waves in order to examine the soliton reflection and its transmission through an inhomogeneous plasma comprising ions, dust grains with fluctuating charge and two types of electrons, namely nonisothermal electrons and isothermal electrons. All the mKdV equations are coupled at the point of reflection and solved for the reflected soliton. Unlike others, a relation is established between the velocity shifts of the incident, reflected and transmitted solitons, and based on a critical value of the shift of incident soliton the strengths of the soliton reflection and transmission are talked about. Conditions are obtained for the soliton reflection and its transmission, and a comparative study is made for the two cases of fixed and fluctuating charges on the dust grains.
Kα x-ray imaging of laser-irradiated, limited-mass zirconium foils
Authors: Storm M. , Eichman B. , Orban C. , Jiang S. , Fiksel G. , Stoeckl C. , Dyer G. , Ditmire T. , Stephens R. , Theobald W. , Delettrez J. A. , Freeman R. R. , Akli K.
Published: July 2014

X-ray fluorescence measurements to determine the effect of target heating on imaging efficiency, at a photon energy of 15.7 keV corresponding to the Kα line of zirconium, have been carried out using limited-mass foils irradiated by the Texas Petawatt Laser. Zirconium foils that ranged in volume from 3000 × 3000 × 21 μm3 to 150 × 150 × 6 μm3 were irradiated with 100 J, 8 ps-long pulses and a mean intensity of 4 × 1019 W/cm2. The Kα emission was measured simultaneously using a highly ordered pyrolytic graphite crystal spectrometer and a curved quartz imaging crystal. The measured ratio of the integrated image signal to the integrated spectral signal was, within the experimental error, constant, indicating that the imaging efficiency's dependence on temperature is weak throughout the probed range. Based on our experience of target heating under similar conditions, we estimate a temperature of ∼200 eV for the smallest targets. The successful imaging of Kα emission for temperatures this high represents an important proof of concept for Zr Kα imaging. At these temperatures, the imaging of Kα emission from lower-Z materials (such as Cu) is limited by temperature-dependent shifts in the Kα emission energy.
Electrical modulation of superconducting critical temperature in liquid-gated thin niobium films
Authors: Choi Jiman , Pradheesh R. , Kim Hyungsang , Im Hyunsik , Chong Yonuk , Chae Dong-Hun
Published: July 2014

We demonstrate that the superconducting critical temperature (Tc) of thin niobium films can be electrically modulated in a liquid-gated geometry device. Tc can be suppressed and enhanced by applying positive and negative gate voltage, respectively, in a reversible manner within a range of about 0.1 K. At a fixed temperature below Tc, we observed that the superconducting critical current can be modulated by gate voltage. This result suggests a possibility of an electrically controlled switching device operating at or above liquid helium temperature, where superconductivity can be turned on or off solely by the applied gate voltage.
Kinetics of silicide formation over a wide range of heating rates spanning six orders of magnitude
Authors: Molina-Ruiz Manel , Lopeandía Aitor F. , Gonzalez-Silveira Marta , Garcia Gemma , Peral Inma , Clavaguera-Mora Maria T. , Rodríguez-Viejo Javier
Published: July 2014

Kinetic processes involving intermediate phase formation are often assumed to follow an Arrhenius temperature dependence. This behavior is usually inferred from limited data over narrow temperature intervals, where the exponential dependence is generally fully satisfied. However, direct evidence over wide temperature intervals is experimentally challenging and data are scarce. Here, we report a study of silicide formation between a 12 nm film of palladium and 15 nm of amorphous silicon in a wide range of heating rates, spanning six orders of magnitude, from 0.1 to 105 K/s, or equivalently more than 300 K of variation in reaction temperature. The calorimetric traces exhibit several distinct exothermic events related to interdiffusion, nucleation of Pd2Si, crystallization of amorphous silicon, and vertical growth of Pd2Si. Interestingly, the thickness of the initial nucleation layer depends on the heating rate revealing enhanced mass diffusion at the fastest heating rates during the initial stages of the reaction. In spite of this, the formation of the silicide strictly follows an Arrhenius temperature dependence over the whole temperature interval explored. A kinetic model is used to fit the calorimetric data over the complete heating rate range. Calorimetry is complemented by structural analysis through transmission electron microscopy and both standard and in-situ synchrotron X-ray diffraction.
Ultrahigh stability of atomically thin metallic glasses
Authors: Cao C. R. , Huang K. Q. , Zhao N. J. , Sun Y. T. , Bai H. Y. , Gu L. , Zheng D. N. , Wang W. H.
Published: July 2014

We report the fabrication and study of thermal stability of atomically thin ZrCu-based metallic glass films. The ultrathin films exhibit striking dynamic properties, ultrahigh thermal stability, and unique crystallization behavior with discrete crystalline nanoparticles sizes. The mechanisms for the remarkable high stability and crystallization behaviors are attributed to the dewetting process of the ultrathin film. We demonstrated a promising avenue for understanding some fundamental issues such as glassy structure, crystallization, deformation, and glass formation through atomic resolution imaging of the two dimensional like metallic glasses.
Tuning magnetotransport in PdPt/Y3Fe5O12: Effects of magnetic proximity and spin-orbit coupling
Authors: Zhou X. , Ma L. , Shi Z. , Guo G. Y. , Hu J. , Wu R. Q. , Zhou S. M.
Published: July 2014

We report that anisotropic magnetoresistance (AMR) and anomalous Hall conductivity (AHC) in the Pd1−xPtx/Y3Fe5O12 (YIG) bilayers could be tuned by varying the Pt concentration (x) and also temperature (T). In particular, the AHC at low T changes its sign when x increases from 0 to 1, agreeing with the negative and positive AHC predicted by our ab initio calculations for the magnetic proximity (MP)-induced ferromagnetic Pd and Pt, respectively. The AMR ratio is enhanced by ten times when x increases from 0 to 1. Furthermore, the AMR of PdPt/YIG bilayers shows similar T-dependence as the magnetic susceptibility of the corresponding bulk Pd/Pt, also indicating the MP effect as the origin of the AMR. The present work demonstrates that the alloying of Pt and Pd not only offers tunable spin-orbit coupling but also is useful to reveal the nature of the AMR and AHC in Pt/YIG bilayers, which are useful for spintronics applications.
Studying food preferences in captive cryptic folivores can assist in conservation planning: the case of the Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi)
Authors: Heise-Pavlov Sigrid , Anderson Clare , Moshier Andrea
Published: July 2014

Food preferences of the arboreal Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi), endemic to the tropical rainforests of north-eastern Australia, are largely unknown, but are likely to affect the movements of this mammal within its home range and across a fragmented landscape. Food selection was investigated by applying a consumption ranking system to 35 browse species provided to six captive animals throughout different years. Animals consumed foliage from a wide range of rainforest tree species, but at different intensities, suggesting that Lumholtz’s tree-kangaroo is a selective folivore. All studied animals showed a general preference for the foliage of the northern olive (Chionanthus ramiflorus) and the umbrella tree (Schefflera actinophylla) throughout the year while foliage from acacias (Acacia spp.), milky pine (Alstonia scholaris) and pink ash (Alphitonia petriei) was less frequently consumed. Foliage from figs (Ficus spp.) and the northern tamarind (Diploglottis diphyllostegia) was consumed at higher rates only at certain times of the year, suggesting the existence of seasonal preferences. The knowledge of general and seasonal food preferences of this large arboreal mammal may allow a better prediction of animal movements and therefore can assist in conservation efforts. Recommendations for the integration of these findings in restoration projects are given.
Analysis and characterisation of bovine oocyte and embryo biomarkers by matrix-assisted desorption ionisation mass spectrometry imaging
Authors: Gonçalves Roseli F. , Ferreira Mónica S. , de Oliveira Diogo N. , Canevarolo Rafael , Achilles Marcos A. , D'Ercole Daniela L. , Bols Peter E. , Visintin Jose A. , Killian Gary J. , Catharino Rodrigo R.
Published: July 2014

In the field of ‘single cell analysis’, many classical strategies like immunofluorescence and electron microscopy are the primary techniques of choice. However, these methodologies are time consuming and do not permit direct identification of specific molecular classes, such as lipids. In the present study, a novel mass spectrometry-based analytical approach was applied to bovine oocytes and embryos. This new metabolomics-based application uses mass spectrometry imaging (MSI), efficient data processing and multivariate data analysis. Metabolic fingerprinting (MF) was applied to the analysis of unfertilised oocytes, 2-, 4- and 8-cell embryos and blastocysts. A semiquantitative strategy for sphingomyelin [SM (16 : 0) + Na]+ (m/z 725) and phosphatidylcholine [PC (32 : 0) + Na]+ (m/z 756) was developed, showing that lipid concentration was useful for selecting the best metabolic biomarkers. This study demonstrates that a combination of MF, MSI features and chemometric analysis can be applied to discriminate cell stages, characterising specific biomarkers and relating them to developmental pathways. This information furthers our understanding of fertilisation and preimplantation events during bovine embryo development.
Comparative RNA-sequencing analysis of myocardial and circulating small RNAs in human heart failure and their utility as biomarkers
Authors: Akat Kemal Marc , Moore-McGriff D’Vesharronne , Morozov Pavel , Brown Miguel , Gogakos Tasos , Correa Da Rosa Joel , Mihailovic Aleksandra , Sauer Markus , Ji Ruiping , Ramarathnam Aarthi , Totary-Jain Hana , Williams Zev , Tuschl Thomas , Schulze P. Christian
Published: July 2014

Significance

Heart failure (HF) has a high morbidity and mortality and its incidence is increasing worldwide. While protein biomarkers have been established for diagnostic and prognostic evaluation of patients with HF, there is currently no systematic assessment of RNA biomarkers. We determined the composition of myocardial tissue and circulating microRNAs (miRNAs) in a large cohort of patients with stable and advanced HF and compared it to the composition of normal adult and fetal samples. The advanced HF patients underwent mechanical unloading with left ventricular assist devices and samples were collected at different postoperative time points. Our findings provide the underpinning for miRNA-based therapies and emphasize the usefulness of circulating miRNAs as biomarkers for heart injury performing similar to established diagnostic protein biomarkers.
Climate sensitivity of intensive rice-wheat systems in tropical Asia: focus on the Indo-Gangetic plains.
Authors: Singh A. K. , Pathak H.
Published: July 2014

This chapter analyses climate change and climatic variation scenarios for South Asia and assesses the vulnerability of the rice-wheat system to climate change. Some adaptation strategies to climate change for the system are suggested, with a focus on the Indo-Gangetic plains.
Diversity in organic and agroecological farming systems for mitigation of climate change impact, with examples from Latin America.
Authors: Rossing W. A. H. , Modernel P. , Tittonell P. A.
Published: July 2014

This chapter reviews the impact of climate change on, and the adaptation potential of, ecologically intensive systems such as those known in different parts of the world as organic farming, or agroecology. To fit into the rationale of this book, this chapter focuses on Latin America, and on the array of organic and agroecological farming systems (OAFS) that coexist in the region. The chapter starts by defining the farming systems focused on in the chapter. Then climate change predictions for Latin America are reviewed and their impacts assessed. Next, recent evidence from global meta-analyses on the performance of OAFS is summarized. Information from OAFS from Latin America is included in the reviews but is too scant to warrant a specific section. Instead, two specific OAFS from Latin America are focused on: coffee production systems and natural grassland systems. Their current status, challenges in view of climate change predictions and adaptation options proposed in the literature are reviewed. The chapter ends by discussing the key features and impediments of OAFS and how they can help to build farming systems in the face of global and climate change.
Climate change and integrated crop-livestock systems in temperate-humid regions of North and South America: mitigation and adaptation.
Authors: Franzluebbers A. J.
Published: July 2014

This chapter focuses on the types of integrated crop-livestock systems in North and South America and reviews soil organic C sequestration and greenhouse gas emissions in integrated crop-livestock systems. The impact of climate change on integrated crop-livestock systems are discussed and prospects for developing greater resilience to climate extremes are presented.
Structural deformation of longitudinal arches during running in soccer players with medial tibial stress syndrome
Authors: Noh Byungjoo , Masunari Akihiko , Akiyama Kei , Fukano Mako , Fukubayashi Toru , Miyakawa Shumpei
Published: July 2014

The purpose of this study was to compare angular change and translational motion from the medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) during running between medial tibial stress syndrome (MTSS) and non‐MTSS subjects. A total of 10 subjects volunteered, comprising 5 subjects with MTSS and 5 subjects without injury (non‐MTSS) as the control group. All subjects performed the test movement that simulated running. Fluoroscopic imaging was used to investigate bone movement during landing in running. Sagittal motion was defined as the angular change and translational motion of the arch. A Mann‐Whitney U‐test was performed to determine the differences in the measured values between the MTSS and non‐MTSS groups. The magnitude of angular change for the MLA and LLA was significantly greater for subjects with MTSS than for control subjects. Translational motion of the MLA and LLA of the MTSS group was also significantly greater than that of the non‐MTSS group (all p < 0.05). Soccer players with MTSS have an abnormal structural deformation of foot during support (or stance) phase of running, with a large decrease in both the MLA and LLA. This abnormal motion could be a risk factor for the development of MTSS in these subjects.
Ultrasonographic Diagnosis of Midgut Volvulus With Malrotation in Children
Authors: Esposito Francesco , Vitale Valerio , Noviello Domenico , Di Serafino Marco , Vallone Gianfranco , Salvatore Marco , Oresta Patrizia
Published: July 2014

Objectives:

Midgut volvulus with malrotation is typical in newborns. We present our experience to emphasize the importance of suspecting midgut volvulus as a cause of abdominal pain also beyond infancy, particularly in relation to malrotation, and the relevance of ultrasonographic (US) signs in its diagnosis.

Methods:

A total of 34 patients (10 boys, 24 girls; ages between 1 day and 12 years) diagnosed as having malrotation or malrotation with volvulus, surgically confirmed, between 2006 and 2013 were retrospectively selected among all of the patients referred to our institution for acute abdomen and bilious vomiting. All of them underwent US and color Doppler examination before surgery. The US examinations were performed with 6 to 10 MHz microconvex and 7.5 to 10 Mhz linear transducer. The transducer was placed under xiphoid, and, with axial projection, the presence of anatomic position reversed between superior mesenteric vein (SMV) and superior mesenteric artery (SMA), as a sign of malrotation, and the presence of “whirlpool sign” (WS) (wrapping of the SMV and the mesentery around the SMA), as a sign of midgut volvulus, were evaluated.

Results:

In 27 of these 34 patients, midgut volvulus was present; 7 patients had intestinal malrotation. In 2 of 7 (28%) patients with malrotation, SMA and SMV were inverted. Among the patients with volvulus, 2 showed reversed vessel position and 22 patients presented the WS in association with SMA/SMV inversion (22/27, 81%).

Conclusions:

Midgut volvulus with malrotation can appear beyond the neonatal age group as demonstrated in our case. The WS sign is sufficiently sensitive for its diagnosis and should be routinely researched at all ages of pediatric population. Anatomic inversion between SMV and SMA seems to be not enough sensitive in isolated malrotation diagnosis.