bluuebunny/crossref_metadata_2025 huggingface dataset:
Endocrine Protection of Ischemic Myocardium by FGF21 from the Liver and Adipose Tissue
Authors: Liu Shu Q. , Roberts Derek , Kharitonenkov Alexei , Zhang Brian , Hanson Samuel M. , Li Yan Chun , Zhang Li-Qun , Wu Yu H.
Published: September 2013

Myocardial ischemia, while causing cardiomyocyte injury, can activate innate protective processes, enhancing myocardial tolerance to ischemia. Such processes are present in not only the heart, but also remote organs. In this investigation, we demonstrated a cardioprotective process involving FGF21 from the liver and adipose tissue. In response to myocardial ischemia/reperfusion injury in the mouse, FGF21 was upregulated and released from the hepatic cells and adipocytes into the circulation and interacted with FGFR1 in cardiomyocytes under the mediation of the cell membrane protein β-Klotho, inducing FGFR1 phosphorylation. This action caused phosphorylation of the signaling molecules PI3K p85, Akt1 and BAD, thereby reducing caspase 3 activity, cell death and myocardial infarction in association with improvement of myocardial function. These observations suggest that FGF21 is upregulated and released from the liver and adipose tissue in myocardial injury, contributing to myocardial protection by the mediation of the FGFR1/β-Klotho–PI3K–Akt1–BAD signaling network.
Auxiliary beam terrain‐scattered interference suppression: reflection system and radar performance
Authors: Björklund Svante , Nelander Anders , Pettersson Mats I.
Published: September 2013

Terrain‐scattered interference (TSI), that is, jammer signals reflected on the earth's surface, is a significant problem to military airborne radar. In auxiliary beam TSI suppression, the TSI in the main radar beam is estimated by a single or several auxiliary beams and is subtracted from the main beam channel. The signal to subtract is the auxiliary beam signals fed through an estimate of the ‘reflection system’, which describes scattering on the surface. The authors first present results on the structure of this TSI suppression, on the estimation of the reflection system and on the quality of the estimate. Then the authors derive theoretical expressions for the signal‐to‐interference plus noise ratio (SINR) and the remaining TSI power for a single auxiliary beam. Since the SINR is directly connected to the radar performance, it can be seen what factors affect the performance and how. It was noted that when the estimated reflection system is missing one or more delays of the true system, the TSI filter cannot suppress the TSI signal completely. This phenomenon, which is called ‘TSI leakage’, has a very large impact on the performance. The SINR cannot be kept constant. Instead, an ‘SINR improvement’ can be defined.
Global navigation satellite system pseudorange‐based multisensor positioning incorporating a multipath error model
Authors: Khider Mohammed , Jost Thomas , Robertson Patrick , Abdo‐Sánchez Elena
Published: September 2013

Pedestrian navigation in challenging areas where global navigation satellite systems (GNSSs) lack the required accuracy and availability, such as indoor and urban canyons, is becoming increasingly important. Multisensor navigation is one of the techniques that has shown promising positioning accuracy in such environments. Being able to appropriately fuse GNSS pseudoranges in a multisensor positioning system is advantageous as it allows us to make use of fewer than four detected satellite signals and to incorporate more accurate estimation models. In this study, a particle filter‐based pedestrian positioning system is enhanced to use pseudorange measurements of a GNSS receiver instead of direct position solutions. By using correctly modelled pseudoranges, a single satellite visible over a certain time period might improve positioning accuracy and robustness when combined with measurements from other positioning sensors, like a foot‐mounted inertial measurement unit. Additionally in this study, a statistical multipath error model for pseudoranges is integrated. Promising results have been achieved in a challenging indoor environment where blockage of satellites’ signals and multipath are common issues.
High‐frequency radar aircraft detection method based on neural networks and time‐frequency algorithm
Authors: Li Ting , Yang Guobin , Wang Pengxun , Chen Gang , Zhou Chen , Zhao Zhengyu , Huang Shuo
Published: September 2013

Aircraft detection is an important application of Wuhan Ionosonde Sounding System (WISS), which recently has been developed by the Ionospheric Laboratory of Wuhan University. Since the ionosphere varies temporally and spatially, severe multipath effects are produced, which jeopardise the characteristic quantities extracting of targets from the recorded data. To solve the above problems and further identify the targets from the fuzzy signals, this study presents a neural networks and time‐frequency‐based algorithm. By neural networks, the characteristic quantities of targets are extracted from the recorded data, and then, the Doppler spectrum of target signals is computed to determine the radial velocity of targets. Moreover, with the help of time‐frequency analysis, the radial velocity variability in time domain can be identified, which finally leads to the identification of the type of the targets. Simulations using the recorded data of the WISS show that the type of the targets is aircraft and 90.9% accurate recognition of aircraft targets can be achieved.
Perspective: Reaches of chemical physics in biology
Authors: Gruebele Martin , Thirumalai D.
Published: September 2013

Chemical physics as a discipline contributes many experimental tools, algorithms, and fundamental theoretical models that can be applied to biological problems. This is especially true now as the molecular level and the systems level descriptions begin to connect, and multi-scale approaches are being developed to solve cutting edge problems in biology. In some cases, the concepts and tools got their start in non-biological fields, and migrated over, such as the idea of glassy landscapes, fluorescence spectroscopy, or master equation approaches. In other cases, the tools were specifically developed with biological physics applications in mind, such as modeling of single molecule trajectories or super-resolution laser techniques. In this introduction to the special topic section on chemical physics of biological systems, we consider a wide range of contributions, all the way from the molecular level, to molecular assemblies, chemical physics of the cell, and finally systems-level approaches, based on the contributions to this special issue. Chemical physicists can look forward to an exciting future where computational tools, analytical models, and new instrumentation will push the boundaries of biological inquiry.
Generalized dephasing relation for fidelity and application as an efficient propagator
Authors: Kocia Lucas , Heller Eric J.
Published: September 2013

The dephasing relation (DR), a linearization of semiclassical fidelity, is generalized to include the overlap of “off-diagonal” elements. The accuracy of the formulation is tested in integrable and chaotic systems and its scaling with dimensionality is studied in a Caldeira-Leggett model with many degrees of freedom. It is shown that the DR is often in very good agreement with numerically analytic quantum results and frequently outperforms an alternative semiclassical treatment. Most importantly, since there is no computationally expensive prefactor, and Monte Carlo Metropolis sampling is used to facilitate the calculation, the DR is found to scale remarkably well with increasing dimension. We further demonstrate that a propagator based on the DR can include more quantum coherence and outperform other popular linearized semiclassical methods, such as forward-backward semiclassical dynamics (FBSD) and the linearized semiclassical initial value representation (LSC-IVR).
Molecular dynamics studies of thermal dissipation during shock induced spalling
Authors: Xiang Meizhen , Hu Haibo , Chen Jun , Liao Yi
Published: September 2013

Under shock loadings, the temperature of materials may vary dramatically during deformation and fracture processes. Thus, thermal effect is important for constructing dynamical failure models. Existing works on thermal dissipation effects are mostly from meso- to macro-scale levels based on phenomenological assumptions. The main purpose of the present work is to provide several atomistic scale perspectives about thermal dissipation during spall fracture by nonequilibrium molecular dynamics simulations on single-crystalline and nanocrystalline Pb. The simulations show that temperature arising starts from the vicinity of voids during spalling. The thermal dissipation rate in void nucleation stage is much higher than that in the later growth and coalescence stages. Both classical spallation and micro-spallation are taken into account. Classical spallation is corresponding to spallation phenomenon where materials keep in solid state during shock compression and release stages, while micro-spallation is corresponding to spallation phenomenon where melting occurs during shock compression and release stages. In classical spallation, whether residuary dislocations are produced in pre-spall stages has significant influences on thermal dissipation rate during void growth and coalescence. The thermal dissipation rates decrease as shock intensity increases. When the shock intensity exceeds the threshold of micro-spallation, the thermal dissipation rate in void nucleation stage drops precipitously. It is found that grain boundaries mainly influence the thermal dissipation rate in void nucleation stage in classical spallation. In micro-spallation, the grain boundary effects are insignificant.
High-resolution Laue-type DuMond curved crystal spectrometer
Authors: Szlachetko M. , Berset M. , Dousse J.-Cl. , Hoszowska J. , Szlachetko J.
Published: September 2013

We report on a high-resolution transmission-type curved crystal spectrometer based on the modified DuMond slit geometry. The spectrometer was developed at the University of Fribourg for the study of photoinduced X-ray spectra. K and L X-ray transitions with energies above about 10 keV can be measured with an instrumental resolution comparable to their natural linewidths. Construction details and operational characteristics of the spectrometer are presented. The variation of the energy resolution as a function of the focal distance and diffraction order is discussed. The high sensitivity of the spectrometer is demonstrated via the 2s-1s dipole-forbidden X-ray transition of Gd which could be observed despite its extremely low intensity. The precision of the instrument is illustrated by comparing the sum of the energies of the Au K–L2 and L2–M3 cascading transitions with the energy of the crossover K–M3 transition as well as by considering the energy differences of the Gd Kα1 X-ray line measured at five different diffraction orders. Finally, to demonstrate the versatility of the spectrometer, it is shown that the latter can also be used for in-house extended X-ray absorption fine structure measurements.
Condensation of the atomic relaxation vibrations in lead-magnesium-niobate at T=T*
Authors: Prosandeev Sergey , Raevski Igor P. , Malitskaya Maria A. , Raevskaya Svetlana I. , Chen Haydn , Chou Chen-Chia , Dkhil Brahim
Published: September 2013

We present neutron diffraction, dielectric permittivity, and photoconductivity measurements, evidencing that lead-magnesium niobate experiences a diffuse phase transformation between the spherical glass and quadrupole glass phases, in the temperature interval between 400 K and 500 K, with the quadrupole phase possessing extremely high magnitudes of dielectric permittivity. Our analysis shows that the integral diffuse scattering intensity may serve as an order parameter for this transformation. Our experimental dielectric permittivity data support this choice. These data are important for the applications desiring giant dielectric responses in a wide temperature intervals and not related to electron's excitations.
Kinetic aspects of the ion current layer in a reconnection outflow exhaust
Authors: Zenitani Seiji , Shinohara Iku , Nagai Tsugunobu , Wada Tomohide
Published: September 2013

Kinetic aspects of the ion current layer at the center of a reconnection outflow exhaust near the X-type region are investigated by a two-dimensional particle-in-cell (PIC) simulation. The layer consists of magnetized electrons and unmagnetized ions that carry a perpendicular electric current. The ion fluid appears to be nonideal, sub-Alfvénic, and nondissipative. The ion velocity distribution functions contain multiple populations, such as global Speiser ions, local Speiser ions, and trapped ions. The particle motion of the local Speiser ions in an appropriately rotated coordinate system explains the ion fluid properties very well. The trapped ions are the first demonstration of the regular orbits in the chaotic particle dynamics [Chen and Palmadesso, J. Geophys. Res. 91, 1499 (1986)] in self-consistent PIC simulations. They would be observational signatures in the ion current layer near reconnection sites.
A multiscale strength model for tantalum over an extended range of strain rates
Authors: Barton N. R. , Rhee M.
Published: September 2013

A strength model for tantalum is developed and exercised across a range of conditions relevant to various types of experimental observations. The model is based on previous multiscale modeling work combined with experimental observations. As such, the model's parameterization includes a hybrid of quantities that arise directly from predictive sub-scale physics models and quantities that are adjusted to align the model with experimental observations. Given current computing and experimental limitations, the response regions for sub-scale physics simulations and detailed experimental observations have been largely disjoint. In formulating the new model and presenting results here, attention is paid to integrated experimental observations that probe strength response at the elevated strain rates where a previous version of the model has generally been successful in predicting experimental data [Barton et al., J. Appl. Phys. 109(7), 073501 (2011)].
Doping effect on the adsorption of NH3 molecule onto graphene quantum dot: From the physisorption to the chemisorption
Authors: Seyed-Talebi Seyedeh Mozhgan , Beheshtian J. , Neek-amal M.
Published: September 2013

The adsorption of ammonia molecule onto a graphene hexagonal flake, aluminum (Al) and boron (B) doped graphene flakes (graphene quantum dots, GQDs) are investigated using density functional theory. We found that NH3 molecule is absorbed to the hollow site through the physisorption mechanism without altering the electronic properties of GQD. However, the adsorption energy of NH3 molecule onto the Al- and B-doped GQDs increases with respect GQD resulting chemisorption. The adsorption of NH3 onto the Al-doped and B-doped GQDs makes graphene locally buckled, i.e., B- doped and Al-doped GQDs are not planar. The adsorption mechanism onto a GQD is different than that of graphene. This study reveals important features of the edge passivation and doping effects of the adsorption mechanism of external molecules onto the graphene quantum dots.
Suppression of magnetic coupling in superconducting GdN-NbN-GdN trilayers
Authors: Senapati Kartik , Blamire Mark G. , Barber Zoe H.
Published: September 2013

We report on the effect of superconducting ordering in an NbN spacer layer on the magnetic coupling behavior in GdN-NbN-GdN trilayers. In the normal state of NbN, the weak ferromagnetic semiconductor GdN layers were found to be antiferromagnetically coupled, as inferred from magnetization measurements. A gradual decrease in the coupling strength was observed on cooling through Tc. Although this is to be expected, due to a decrease in the quasiparticle density of states (due to Cooper pairing), there has been no experimental confirmation so far. The gradual decrease in coupling strength above Tc correlates well with the appearance of superconducting fluctuations in the spacer NbN layer.
Low-threshold lasing action in an asymmetric double ZnO/ZnMgO quantum well structure
Authors: Su S. C. , Zhu H. , Zhang L. X. , He M. , Zhao L. Z. , Yu S. F. , Wang J. N. , Ling F. C. C.
Published: September 2013

ZnO/Zn0.85Mg0.15O asymmetric double quantum well (ADQW) and multiple quantum well (MQW) were fabricated with plasma assisted molecular epitaxy on c-plane sapphire, with their optical properties and optical pumped lasing characteristics studied. Due to the good crystalline quality, the lasing threshold of the MQW is ∼20 kW cm−2. The widths of the narrow well (NW) and the wide well (WW) of the ADQW were chosen to fascinate rapid LO phonon assisted carrier tunneling from NW to WW, so as to enhance the exciton density at the WW. Very low lasing threshold of 6 kW cm−2 has been achieved.
Induced magneto-transport properties at palladium/yttrium iron garnet interface
Authors: Lin Tao , Tang Chi , Shi Jing
Published: September 2013

As a thin layer of palladium (Pd) is directly deposited on an yttrium iron garnet or YIG (Y3Fe5O12) magnetic insulator film, Pd develops both low- and high-field magneto-transport effects that are absent in standalone Pd or thick Pd on YIG. While the low-field magnetoresistance peak of Pd tracks the coercive field of the YIG film, the much larger high-field magnetoresistance and the Hall effect do not show any obvious relationship with the bulk YIG magnetization. The distinct high-field magneto-transport effects in Pd are shown to be caused by interfacial local moments in Pd.
Two forms of nanoscale order in amorphous GexSe1−x alloys
Authors: Darmawikarta Kristof , Li Tian , Bishop Stephen G. , Abelson John R.
Published: September 2013

We analyze the evolution of nanoscale order in amorphous GexSe1−x alloys using fluctuation electron microscopy. We identify two distinct structural signatures that behave independently as a function of composition. The strong signature of order at scattering vectors k ∼ 0.30 and 0.55 Å−1 in Ge-rich alloys (x > 0.40) diminishes rapidly in Se-rich compositions. However, a second signature of order at scattering vector k ∼ 0.15 Å−1 appears only for compositions in the middle range x = 0.30–0.53. We interpret that structural ordering occurs among pure Ge tetrahedra or among GeSe4 tetrahedra, respectively, in amorphous GexSe1−x.
Influence of the packing fraction and host matrix on the magnetoelastic anisotropy in Ni nanowire composite arrays
Authors: Piraux Luc , Hamoir Gaël , Encinas Armando , De La Torre Medina Joaquin , Abreu Araujo Flavio
Published: September 2013

The influence of the packing fraction on thermally induced magnetoelastic effects has been studied in Ni nanowires embedded in polycarbonate, poly(vinylidene difluoride), and alumina nanoporous membranes of different porosities for temperatures between 77 K and 345 K. For nanowires embedded in polymer membranes, the contrasting shift in the ferromagnetic resonance frequency when the temperature is either above or below ambient temperature is consistent with the occurrence of uniaxial magnetoelastic anisotropy effects due to the large thermal expansion coefficient mismatch between the metal nanowires and the membrane. A model which considers the influence of the nanowires packing fraction and the membrane material on the magnetoelastic effects, arising from the matrix-assisted deformation process, is proposed. The model is able to successfully explain the experimentally observed effects for the Ni nanowire arrays embedded in the different porous membranes and their variation with the packing fraction. The possibility to modulate the magnetic anisotropy of such nanocomposites by an appropriate choice of membrane material, packing fraction, and sample temperature is of considerable importance to achieve magnetically tunable devices.
Influence of a low anisotropy grain on magnetization reversal in polycrystalline bit-patterned media
Authors: Kaganovskiy Leon , Lau June W. , Khizroev Sakhrat , Litvinov Dmitri
Published: September 2013

We compute the switching field in a disk-shaped polycrystalline exchange-coupled bit (similar material to those found in bit-patterned media (BPM)) with micromagnetics, by varying physical parameters of a test grain. It was found that the size and the anisotropy of the test grain have substantial effects on the switching field, while its location has only minor influence. Scaling of the bit and the test grain dimensions result in similar switching properties. Switching field was reduced when the number of the low anisotropy test grains increased. Additionally, it was established that the intergranular exchange coupling needs to be at least 10% of the intragrain exchange for the bit to behave as one exchange-coupled entity. This investigation provides some insights for optimizing the material microstructure for the BPM application.
Communication: IR spectroscopy of neutral transition metal clusters through thermionic emission
Authors: Lapoutre Vivike J. F. , Haertelt Marko , Meijer Gerard , Fielicke André , Bakker Joost M.
Published: September 2013

The resonant multiple photon excitation of neutral niobium clusters using tunable infrared (IR) radiation leads to thermionic emission. By measuring the mass-resolved ionization yield as a function of IR wavenumber species selective IR spectra are obtained for Nbn (n = 5–20) over the 200–350 cm−1 spectral range. The IR resonance-enhanced multiple photon ionization spectra obtained this way are in good agreement with those measured using IR photodissociation of neutral Nbn-Ar clusters. An investigation of the factors determining the applicability of this technique identifies the internal energy threshold towards thermionic emission in combination with a minimum required photon flux that rapidly grows as a function of excitation wavelength.
Passivation of titanium by hydrogen in silicon
Authors: Leonard S. , Markevich V. P. , Peaker A. R. , Hamilton B.
Published: September 2013

Interactions of hydrogen with titanium have been studied in Ti-doped n-type crystalline Si using capacitance-voltage profiling and deep level transient spectroscopy (DLTS). Hydrogen plasma treatments of the samples at room temperature have resulted in the suppression of DLTS signals due to interstitial Ti atoms (Tii) and the appearance of three strong DLTS peaks, which are related to three different Ti-H defects. After annealing of the hydrogenated samples at 150 °C in nitrogen, the signals due to Tii and two of the three H-related defects were not detected in the spectra showing that almost complete passivation of all electrically active defects occurred.
Volatile and nonvolatile magnetic easy-axis rotation in epitaxial ferromagnetic thin films on ferroelectric single crystal substrates
Authors: Wang Z. , Wang Y. , Ge W. , Li J. , Viehland D.
Published: September 2013

We explored the relationship between phase transformation and magnetoelectric effect by depositing epitaxial CoFe2O4 films on ⟨110⟩ oriented Pb(Mg,Nb)O3-PbTiO3 (PMN-PT) with three different PbTiO3 contents (PMN-28PT, PMN-29.5PT, and PMN-30PT). Electric-field controlled rhombohedral to orthorhombic phase transformation was confirmed by both piezoelectric and dielectric constant measurements. A giant in-plane (IP) uniaxial strain in CoFe2O4 film was induced due to dramatic lattice parameter change trigged by phase transition. Magnetic easy axis can be rotated from IP⟨110⟩ to IP⟨001⟩. More importantly, the phase transformation could be either reversible or irreversible, resulting in either volatile or nonvolatile magnetic easy axis rotations.
Optimization and temperature dependence characteristics of low temperature In0.3Ga0.7As and In0.53Ga0.47As-In0.52Al0.48As semiconductor terahertz photoconductors
Authors: Kostakis I. , Missous M.
Published: September 2013

Recently, detailed characterisation of materials and evaluation of devices based on low temperature (LT) grown InGaAs-InAlAs and GaAs-based terahertz (THZ) photoconductors using the Molecular Beam Epitaxy (MBE) technique have been reported by our group. In this work, the characterisation is extended in order to study the growth reproducibility of the photoconductors and the temperature dependence of their transport properties. We show that the structural, optical and transport characteristics of a photoconductor can be optimised by growing the same structure under the same growing conditions but in different MBE systems. The Hall Effect measurements over the temperature range of 100 K–400 K revealed temperature independency of the mobility within a wide range, in which the concentration is changing with the temperature. The majority of carriers are found to be electrons even in the case of Be doped samples, which is attributed to the large density of excess As anti-site atoms. The transport properties of low temperature grown materials are presented for the first time and the behaviour is found to be different to those of conventional materials, which are grown under normal growth conditions.
How Graphene Oxide Quenches Fluorescence of Rhodamine 6G
Authors: Fan Kai-li , Guo Zhen-kun , Geng Zhi-gang , Ge Jing , Jiang Shen-long , Hu Jia-hua , Zhang Qun
Published: September 2013

We investigate the fluorescence quenching of Rhodamine 6G (R6G), a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide (GO) in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption variation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes between R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoinduced electron transfer between R6G and GO has been discussed.
Helium Droplets: An Apparatus to Study Ultra Cold Chemistry
Authors: Zhang Cui-mei , Zhang Zhi-guo , Huang Cun-shun , Zhang Qun , Chen Yang
Published: September 2013

A new pulsed helium nano droplets machine has been constructed. The droplets were generated by expansion of the pure helium through the cryogenic valve attached to a closed-cycle cryostat. The mean size of helium droplets can be controlled between 103 and 105 helium atoms by tuning the backing pressure (10–40 bar) and temperature (10–30 K). Compared with the continuous-flow beam source, the density of droplet is at least one order of magnitude higher, which offers the opportunity to combine the system with the commercial pulsed laser to study chemical reactions inside of the superfluid helium at ultra-low temperature. The performance for the system has been checked by studying the photodissociation of CH3I doped droplets at 252 nm with the velocity map imaging technique. The photofragments, CH3, were detected by (2+1) resonance enhanced multiphoton ionization. The speed and angular distributions derived from resulting images show clear evidence of the relaxation effect by the surrounding helium atoms. The pulsed helium droplets depletion spectroscopy was also demonstrated. The depletion spectrum of benzene doped helium droplets indicates that less than 3% depletion can be observed with the newly constructed apparatus.
Ab initio Study of Complexation Process between Poly(amido-amine) and Nano-Silicon Dioxide
Authors: Jin Tao , Lü Hai-liang
Published: September 2013

To understand better the molecular-level details of ≡Si+ (SC) or ≡SiO− (SOA) ion group to -NH2 teminated poly(amido-amine) dendrimers in the gas phase, density functional theory is used to optimize the minimum energy and transition state structures with UB3LYP/6-311G (d) and HF/6-31G levels. The tertiary amine nitrogen and the amide oxygen are found to be the most favorable binding sites. The activation energies of the different active sites and the reaction steps of SC and/or SOA ion group and the amide sites are also analyzed. The stable compounds are formed via the electrostatic interaction and the coordination effect. The orientation of the amide O and the rotation of the branches minimizes the energy of the whole system.
Adsorption Reaction Dynamics of Systems Lysozyme and Nanodiamond/Nanosilica at pH=7–13
Authors: Chao Victor Wei-Keh
Published: September 2013

Adsorption reactions between surfaces of nanodiamond and nanosilica with diameter of 100 nm prepared as suspension solutions of 0.25 μg/μL and lysozyme molecule with different concentrations of 7 mmol/L PPBS at pH=7, 9, 11, and 13 have been investigated by fluorescence spectroscopy. Adsorption reaction constants and coverages of lysozyme with different concentrations of 0–1000 nmol/L under the influences of different pH values have been obtained. Helicities and conformations of the adsorbed lysozyme molecules, free spaces of every adsorbed lysozyme molecule on the surfaces of nanoparticles at different concentrations and pH values have been deduced and discussed. The highest adsorption capabilities for both systems and conformational efficiency of the adsorbed lysozyme molecule at pH=13 have been obtained. Lysozyme molecules can be prepared, adsorbed and carried with optimal activity and helicity, with 2 and 10 mg/m2 on unit nanosurface, 130 and 150 mg/g with respect to the weight of nanoparticle, within the linear regions of the coverages at around 150–250 nmol/L and four pH values for nanodiamond and nanosilica, respectively. They can be prepared in the tightest packed form, with 20 and 55 mg/m2, 810–1680 and 580-1100 mg/g at threshold concentrations and four pH values for nanodiamond and nanosilica, respectively.
Photovoltaic Performance of Triphenylamine Dyes-sensitized Solar Cells Employing Cobalt Redox Shuttle and Influence of π-conjugated Spacers
Authors: Jia Jiang-nan , Tang Kai , Liang Mao , Han Hong-yu , Wu Quan-ping , Xue Song
Published: September 2013

Developing photosensitizers suitable for the cobalt electrolyte and understanding the structure-property relationship of organic dyes is warranted for the dye-sensitized solar cells (DSSCs). The DSSCs incorporating tris(1,10-phenanthroline)cobalt(II/III)-based redox electrolyte and four synthesized organic dyes as photosensitizers are described. The photovoltaic performance of these dyes-sensitized solar cells employing the cobalt redox shuttle and the influences of the π-conjugated spacers of organic dyes upon the photovoltage and photocurrent of mesoscopic titania solar cells are investigated. It is found that organic dyes with thiophene derivates as linkers are suitable for DSSCs employing cobalt electrolytes. DSSCs sensitized with the as-synthesized dyes in combination with the cobalt redox shuttle yield an overall power conversion efficiency of 6.1% under 100 mW/cm2 AM1.5 G illumination.
Theoretical Study on Optical Properties of Oligofluorenes
Authors: Song Jian , Liu Yu-fang
Published: September 2013

We present theoretical investigations on structure-property correlations in fluorenone (FLO) and benzothiadiazole (BT) substituted oligofluorenes (OFLs) derived mainly from the chain morphology, thermal vibration and conjugated extent. Both the vertical absorptions and the vibrationally-resolved absorption and fluorescence spectra have been calculated by the combination of ab initio and time-dependent density functional theory. By properly taking into account of the anharmonic torsion potentials in the OFLs, we have reasonably reproduced the experimentally observed spectroscopic features. Both FLO and BT on-chain chemical defects acting as charge-trapping sites for singlet excitations, are responsible for long wave absorption and emission species, and thus alter the blue light-emitting properties of OFLs. As temperature decreases, the electronic spectral lineshapes of FLO-substituted oligomers become more structured. The lineshapes of BT-substituted oligomers are always smooth and featureless because of less low collective modes resonance. A more gentle excited potential energy surface of BT-mixed molecules can enhance electronic delocalization and achieve bigger red shifts.
Catalytic Performance of MnOx Nanorods in Aerobic Oxidation of Benzyl Alcohol
Authors: Yang Jing , Hua Qing , Chang Su-jie , Yu Xian-qin , Ma Yun-sheng , Huang Wei-xin
Published: September 2013

Various manganese oxide nanorods with similar one-dimensional morphology were prepared by calcination of MnOOH nanorods under different gas atmosphere and at different temperatures, which were synthesized by a hydrothermal route. The morphology and structure of MnOx catalysts were characterized by a series of techniques including X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and temperature programmed reduction (TPR). The catalytic activities of the prepared MnOx nanorods were tested in the liquid phase aerobic oxidation of benzyl alcohol, which follow a sequence as MnO2>Mn2O3≈Mn3O4>MnOOH with benzaldehyde being the main product. On the basis of H2-TPR results, the superior activity of MnO2 is ascribed to its lower reduction temperature and therefore high oxygen mobility and excellent redox ability. Moreover, a good recycling ability was observed over MnO2 catalysts by simply thermal treatment in air.
Improvement on Electrical Properties and Magnetoresistance Induced by Pd or Ag Addition in La0.67(Ca0.65Ba0.35)0.33MnO3 Manganites
Authors: Yuan Xiao-bo , Ren Jun-feng
Published: September 2013

Electrical properties and magnetoresistance have been studied in two series of xAg- La0.67(Ca0.65Ba0.35)0.33MnO3 and xPd-La0.67(Ca0.65Ba0.35)0.33MnC3 (abbreviated by xAg- LCBMO and xPd-LCBMO) composites. Both Pd and Ag addition induce a decrease in resistivity and an increase in temperature at which the resistivity reaches its maximum. This is mainly due to the improvement of grain boundaries caused by the segregation of good conductive metal grains on the grain boundaries/surfaces. In addition, both Pd and Ag addition induce a large enhancement of room temperature magnetoresistance (RTMR). Note that 27% molar ratio of Ag addition induces a large RTMR of about 70%, about ten times larger than pure LCBMO, whereas 27%molar ratio Pd addition brings a much larger RTMR of about 170%. The large enhancements of MR can be attributed to the decrease in resistivity of the samples caused by the good conductive metal. On the other hand, the polarization of Pd atoms near the Mn ions on the grain surfaces/boundaries plays a very important role in the increase in MR, which induces a large number of spin clusters in Pd-added samples.
Carriers-assisted Enhanced Ferromagnetism in Al-doped ZnMnO Nano-crystallites
Authors: Atiq Shahid , Siddiqi Saadat A. , Abbas Fazal , Saleem Murtaza , Ramay Shahid M.
Published: September 2013

Zn0.95−xAlxMn0.05O (x=0, 0.03, 0.05, and 0.07) dilute magnetic semiconductor materials have been synthesized by sol-gel auto-combustion technique. The effect of Al doping on the structural, electrical, and magnetic properties has been investigated. X-ray diffraction studies demonstrate the existence of single phase characteristic hexagonal wurtzite type crystal structure, similar to the host ZnO, in all the synthesized compositions. Although, the microscopic images revealed that the grains were clustered, yet some individual grains could be seen to have hexagonal texture. Electrical resistivity was observed to decrease with the rise of temperature up to 450 °C, depicting the characteristic semiconductor behavior. Room temperature ferromagnetic behavior was observed in all the compositions. The value of saturation magnetization increased with the increase of Al concentration in ZnMnO system referred to the gradual enhancement of free carriers.
Kinetics of Thermal Decomposition of Lithium Hexafluorophosphate
Authors: Liu Xiao-min , Yang Hui
Published: September 2013

With on-line coupled thermo-gravimetric analyzer-Fourier transform infrared spectrometer technique, the thermal decomposition of lithium hexafluorophosphate (LiPF6) and its gas evolution at inert environment (H2O<10 ppm) were studied under both non-isothermal and isothermal conditions. The results showed that the LiPF6 decomposition is a single-stage reaction with LiF as final residue and PF5 as gas product. In addition, its decomposition kinetics was determined as 2D phase boundary movement (cylindrical symmetry) under both non-isothermal and isothermal conditions. Furthermore, the activation energy of LiPF6 decomposition was calculated as 104 and 92 kJ/mol for non-isothermal and isothermal conditions, respectively.
Role of Bridge-bonded Formate in Formic Acid Dehydration to CO at Pt Electrode: Electrochemial in-situ Infrared Spectroscopic Study
Authors: Zhang Zun-biao , Xu Jie , Kang Jing , Chen Yan-xia
Published: September 2013

Formic acid (HCOOH) decomposition at Pt film electrode has been studied by electrochemical in situ FTIR spectroscopy under attenuated-total-reflection configuration, in order to clarify whether bridge-bonded formate (HCOOb) is the reactive intermediate for COad formation from HCOOH molecules. When switching from HCOOH-free solution to HCOOH-containing solution at constant potential (E=0.4 V vs. RHE), we found that immediately upon solution switch COad formation rate is the highest, while surface coverage of formate is zero, then after COad formation rate decreases, while formate coverage reaches a steady state coverage quickly within ca. 1 s. Potential step experiment from E=0.75 V to 0.35 V, reveals that formate band intensity drops immediately right after the potential step, while the COad signal develops slowly with time. Both facts indicate that formate is not the reactive intermediate for formic acid dehydration to CO.
Optimizing water permeability through the hourglass shape of aquaporins
Authors: Gravelle Simon , Joly Laurent , Detcheverry François , Ybert Christophe , Cottin-Bizonne Cécile , Bocquet Lydéric
Published: September 2013

Significance

Aquaporin channels are able to selectively conduct water across cell membranes, with remarkable efficiency. Although molecular details are crucial to the pore performance, permeability is also strongly limited by viscous dissipation at the entrances. Could the hourglass shape of aquaporins optimize such entrance effects? We show that conical entrances with suitable opening angle can indeed provide a large increase of the channel permeability. Strikingly, the optimal opening angles compare well with the angles measured in a large variety of aquaporins, suggesting that their hourglass shape could be the result of a natural selection process toward optimal permeability. This work also provides guidelines to optimize the performances of artificial nanopores, with applications in desalination, ultrafiltration, or energy conversion.
A functional sequence-specific interaction between influenza A virus genomic RNA segments
Authors: Gavazzi Cyrille , Yver Matthieu , Isel Catherine , Smyth Redmond P. , Rosa-Calatrava Manuel , Lina Bruno , Moulès Vincent , Marquet Roland
Published: September 2013

Significance

Influenza A viruses cause annual influenza epidemics and occasional severe pandemics. Their genome is segmented into eight RNA fragments, which offers evolutionary advantages but complicates genomic packaging. The existence of a selective mechanism ensuring specific packaging of one copy of each RNA into each virion is suspected, but its molecular details remain unknown. We identified a direct interaction between two viral genomic RNA segments of an influenza A virus and demonstrated that this interaction takes place in infected cells, is required for optimal viral replication, and favors copackaging of the interacting RNA segments. Collectively, our experiments indicate that viral RNA segments can promote selective packaging of the influenza A virus genome by forming a sequence-dependent supramolecular network of interactions.
14-3-3σ stabilizes a complex of soluble actin and intermediate filament to enable breast tumor invasion
Authors: Boudreau Aaron , Tanner Kandice , Wang Daojing , Geyer Felipe C. , Reis-Filho Jorge S. , Bissell Mina J.
Published: September 2013

Significance

We characterize a mechanism by which 14-3-3σ directs cell migration and tumor invasion through regulating cytoskeletal solubility and dynamics. Our data suggest that 14-3-3σ expression, rather than being a tumor suppressor, in fact, aids in breast tumor invasion at least in a subset of carcinomas. Our findings warrant further investigation into the role of this molecule in normal mammary gland and breast tumors and, indeed, in epithelial tissues and tumors where 14-3-3σ is expressed.
Tudor domain containing 12 (TDRD12) is essential for secondary PIWI interacting RNA biogenesis in mice
Authors: Pandey Radha Raman , Tokuzawa Yoshimi , Yang Zhaolin , Hayashi Eri , Ichisaka Tomoko , Kajita Shimpei , Asano Yuka , Kunieda Tetsuo , Sachidanandam Ravi , Chuma Shinichiro , Yamanaka Shinya , Pillai Ramesh S.
Published: September 2013

Significance

Large parts of eukaryotic genomes are composed of transposons. Mammalian genomes use DNA methylation to silence these genomic parasites. A class of small RNAs called Piwi-interacting RNAs (piRNAs) is used to specifically guide the DNA methylation machinery to the transposon DNA elements. How germ cells make piRNAs is not entirely understood. We identify a mouse protein and demonstrate its importance for transposon silencing. We find that the protein collaborates with other factors already implicated in piRNA production. Moreover, the protein is required for piRNA production and assembly of the nuclear silencing complex. Physiological importance of the protein is highlighted by the fact that male mice lacking the protein are infertile. This study will greatly benefit the field of germ-cell biology.
Public Reporting of Healthcare-Associated Infections: Epidemiologists' Perspectives
Authors: McGuckin Maryanne , Govednik John , Hyman David , Black Bernard
Published: September 2013

Public reporting of healthcare-associated infections is pervasive, with 33 states and the District of Columbia mandating public disclosure. We surveyed hospital epidemiologists on the perceived value of state public reports. Respondents believed consumers are unaware and do not consider the information important, but they indicated that epidemiologists have a role in consumer education.
Eisenstein series on affine Kac-Moody groups over function fields
Authors: Lee Kyu-Hwan , Lombardo Philip
Published: September 2013

In his pioneering work, H. Garland constructed Eisenstein series on affine Kac-Moody groups over the field of real numbers. He established the almost everywhere convergence of these series, obtained a formula for their constant terms, and proved a functional equation for the constant terms. In his subsequent paper, the convergence of the Eisenstein series was obtained. In this paper, we define Eisenstein series on affine Kac-Moody groups over global function fields using an adelic approach. In the course of proving the convergence of these Eisenstein series, we also calculate a formula for the constant terms and prove their convergence and functional equations.
Dichotomous roles of leptin and adiponectin as enforcers against lipotoxicity during feast and famine
Authors: Unger Roger H. , Scherer Philipp E. , Holland William L.
Published: September 2013

Science is marked by the death of dogmas; the discovery that adipocytes are more than just lipid-storing cells but rather produce potent hormones is one such example that caught physiologists by surprise and reshaped our views of metabolism. While we once considered the adipocyte as a passive storage organ for efficient storage of long-term energy reserves in the form of triglyceride, we now appreciate the general idea (once a radical one) that adipocytes are sophisticated enough to have potent endocrine functions. Over the past two decades, the discoveries of these adipose-derived factors (“adipokines”) and their mechanistic actions have left us marveling at and struggling to understand the role these factors serve in physiology and the pathophysiology of obesity and diabetes. These hormones may serve an integral role in protecting nonadipose tissues from lipid-induced damage during nutrient-deprived or replete states. As such, adipocytes deliver not only potentially cytotoxic free fatty acids but, along with these lipids, antilipotoxic adipokines such as leptin, adiponectin, and fibroblast growth factor 21 that potently eliminate excessive local accumulation of these lipids or their conversion to unfavorable sphingolipid intermediates.
NFκB1 (p50) suppresses SOD2 expression by inhibiting FoxO3a transactivation in a miR190/PHLPP1/Akt-dependent axis
Authors: Du Kejun , Yu Yonghui , Zhang Dongyun , Luo Wenjing , Huang Haishan , Chen Jingyuan , Gao Jimin , Huang Chuanshu
Published: September 2013

The biological functions of nuclear factor κB1 (NFκB1; p50) have not been studied as often as those of other members of the NFκB family due to its lack of a transcriptional domain. Our recent studies showed that p50 functions as an apoptotic mediator via its inhibition of GADD45α protein degradation and increase in p53 protein translation. Here we report a novel function of p50 in its regulation of superoxide dismutase 2 (SOD2) transcription via an NFκB-independent pathway. We find that deletion of p50 in mouse embryonic fibroblasts (MEFs; p50−/−) up-regulates SOD2 expression at both protein and mRNA levels. SOD2 promoter–driven luciferase is also up-regulated in p50−/− cells compared with wild-type (WT) MEF (p50+/+) cells, suggesting p50 regulation of SOD2 at the transcriptional level. Our results also show that p50 deficiency specifically results in down-regulation of phosphorylation and increased transactivation of FoxO3a compared with WT cells. Further studies indicate that p50–down-regulated FoxO3a phosphorylation is mediated by activated Akt via up-regulation of microRNA 190 (miR190), in turn inhibiting PH domain and leucine-rich repeat protein phosphatase 1 (PHLPP1) translation. Together our studies identify a novel p50 function in the regulation of SOD2 transcription by modulating the miR190/PHLPP1/Akt-FoxO3a pathway, which provides significant insight into the physiological function of p50.
BlastGraph: a comparative genomics tool based on BLAST and graph algorithms
Authors: Ye Yanbo , Wei Bo , Wen Lei , Rayner Simon
Published: September 2013

Summary: BlastGraph is an interactive Java program for comparative genome analysis based on Basic Local Alignment Search Tool (BLAST), graph clustering and data visualization. The software generates clusters of sequences of multiple genomes from all-to-all BLAST results and visualizes the results in graph plots together with related information such as sequence features, gene conservation and similarity relationships. Pruning algorithms are used to reduce results to more meaningful subclusters. Subsequent analyses can then be conducted based on the predicted clusters, including gene content, genome phylogenetics and gene gain and loss.

Availability and implementation:  https://github.com/bigwiv/BlastGraph.

Contact:  simon.rayner.cn@gmail.com

Supplementary information:  Supplementary data are available at Bioinformatics online.
Rhizobium laguerreae sp. nov. nodulates Vicia faba on several continents
Authors: Saïdi Sabrine , Ramírez-Bahena Martha-Helena , Santillana Nery , Zúñiga Doris , Álvarez-Martínez Estela , Peix Alvaro , Mhamdi Ridha , Velázquez Encarna
Published: September 2013

Several fast-growing strains nodulating Vicia faba in Peru, Spain and Tunisia formed a cluster related to

Rhizobium leguminosarum

. The 16S rRNA gene sequences were identical to that of

R. leguminosarum

USDA 2370T, whereas rpoB, recA and atpD gene sequences were phylogenetically distant, with sequence similarities of less than 96 %, 97 % and 94 %, respectively. DNA–DNA hybridization analysis showed a mean relatedness value of 43 % between strain FB206T and

R. leguminosarum

USDA 2370T. Phenotypic characteristics of the novel strains also differed from those of the closest related species of the genus

Rhizobium

. Therefore, based on genotypic and phenotypic data obtained in this study, we propose to classify this group of strains nodulating Vicia faba as a novel species of the genus

Rhizobium

named

Rhizobium

laguerreae sp. nov. The type strain is FB206T ( = LMG 27434T = CECT 8280T).