bluuebunny/crossref_metadata_2025 huggingface dataset:
ECM–oligourethene–silica hydrogels as a local drug release system of dexamethasone for stimulating macrophages
Authors: Rangel-Argote Magdalena , Claudio-Rizo Jesús A. , Castellano Laura E. , Vega-González Arturo , Mata-Mata José L. , Mendoza-Novelo Birzabith
Published: February 2017

The incorporation of silica particles inside of extracellular matrix hydrogels supports the loading and releasing of dexamethasone, a therapeutic for modulating macrophage.
Toward a uniform description of hydrogen bonds and halogen bonds: correlations of interaction energies with various geometric, electronic and topological parameters
Authors: Zou Jian-Wei , Huang Meilan , Hu Gui-Xiang , Jiang Yong-Jun
Published: February 2017

Correlations between interaction energies and various structural parameters were established to reveal the differences between hydrogen bonds and halogen bonds.
Gold-catalyzed ring-expansion through acyl migration to afford furan-fused polycyclic compounds
Authors: Zhang Changyuan , Jiang Huanfeng , Zhu Shifa
Published: February 2017

A gold-catalyzed ring-expansion reaction of alkynones to access furan-fused polycyclic compounds is reported.
Ruthenium-catalysed multicomponent synthesis of borasiloxanes
Authors: Chatterjee Basujit , Gunanathan Chidambaram
Published: February 2017

Ruthenium-catalysed multicomponent synthesis of borasiloxanes directly from silanes, boranes and water is reported.
Incorporation of a platinum center in the pi-conjugated core of push–pull chromophores for nonlinear optics (NLO)
Authors: Durand Raphaël J. , Gauthier Sébastien , Achelle Sylvain , Kahlal Samia , Saillard Jean-Yves , Barsella Alberto , Wojcik Laurianne , Le Poul Nicolas , Robin-Le Guen Françoise
Published: February 2017

D–π-Pt–π-A platinum(ii) complexes with pyranylidene electron-donating groups and diazine electron-withdrawing groups are described.
Correction: A mechanistic understanding of the degradation of trace organic contaminants by UV/hydrogen peroxide, UV/persulfate and UV/free chlorine for water reuse
Authors: Li Wei , Jain Tushar , Ishida Kenneth , Remucal Christina K. , Liu Haizhou
Published: February 2017

Correction for ‘A mechanistic understanding of the degradation of trace organic contaminants by UV/hydrogen peroxide, UV/persulfate and UV/free chlorine for water reuse’ by Wei Li et al., Environ. Sci.: Water Res. Technol., 2017, 3, 128–138.
Enantioselective synthesis of spiro γ-butyrolactones by N-heterocyclic carbene (NHC)-catalyzed formal [3 + 2] annulation of enals with 3-hydroxy oxindoles
Authors: Mukherjee Subrata , Joseph Sumi , Bhunia Anup , Gonnade Rajesh G. , Yetra Santhivardhana Reddy , Biju Akkattu T.
Published: February 2017

The NHC-catalyzed enantioselective, oxidative formal [3 + 2] annulation of α,β-unsaturated aldehydes with 3-hydroxy oxindoles is presented.
Surface-plasmon-induced azo coupling reaction between nitro compounds on dendritic silver monitored by surface-enhanced Raman spectroscopy
Authors: Cho Feng-Hsuan , Kuo Shan-Chi , Lai Ying-Huang
Published: February 2017

Azo coupling reactions with a 4-NTP-functionalized Ag-Ds/GCE composites.
Continuous flow synthesis of indoles by Pd-catalyzed deoxygenation of 2-nitrostilbenes with carbon monoxide
Authors: Glotz Gabriel , Gutmann Bernhard , Hanselmann Paul , Kulesza Anna , Roberge Dominique , Kappe C. Oliver
Published: February 2017

The palladium-catalyzed cyclization of o-vinylnitrobenzenes employing carbon monoxide as terminal reductant is investigated. The reaction proceeds with 1 to 2 mol% of Pd(OAc)2 and generates carbon dioxide as the only stoichiometric side-product.
Effective method to determine time‐delay stability margin and its application to power systems
Authors: Dong Chaoyu , Jia Hongjie , Jiang Tao , Bai Linquan , Hu Qinran , Wang Lei , Jiang Yilang
Published: February 2017

In an interconnected bulk power system, wide‐area measurement system (WAMS) can provide abundant remote measurement for the coordinated control system. However, WAMS data have obvious time delays, which affect the performance of the control system and should be properly considered. Time‐delay stability margin (TDSM) is an index to reflect the maximum delay that a time‐delay system can sustain without losing its stability. To construct a coordinated control system based on WAMS data, it is crucial to accurately and rapidly determine the TDSM value. In this paper, a novel Jordan‐Taylor‐Schur (JTS) approach to determine the TDSM value of power system is proposed. It consists of three, Jordan standardization, Taylor separation and Schur simplification. With the three procedures of this method, the model dimension of time‐delay system can be reduced, and the stability criterion derivation can be rebuilt to omit some unnecessary variables so that both the computational efficiency and accuracy can be boosted. Further, it is worth highlighting that the proposed method can be applied to various Lyapunov‐based stability criteria to improve their efficiency with small errors. Finally, three power systems with time delays have been used to demonstrate the effectiveness of the proposed method.
Variation of UPFC controllable parameters during power swing and their impacts on distance relay
Authors: Khodaparast Jalal , Khederzadeh Mojtaba , Faria da Silva Filipe , Bak Claus Leth
Published: February 2017

Unified power flow controller (UPFC) has impact on the performance of distance relay during power swing. Generally, power system's parameters oscillate during power swing and since UPFC operation depends on some of these parameters (bus voltage, active and reactive power), the UPFC injects oscillated series voltage and draws oscillated shunt current. These oscillating series voltage and shunt current influence distance relays, as the impedance seen by a distance relay during power swing changes in UPFC‐compensated lines. This study shows how and why series voltage and shunt current change during power swing. Moreover, the admittance swing characteristic is proposed in this study and effects of series and shunt branches of UPFC on the admittance seen by a distance relay during power swing have been examined.
Family of soft‐switching pulse‐width modulation converters using coupled passive snubber
Authors: Esteki Morteza , Mohammadi Mehdi , Yazdani Mohammad Rouhollah , Adib Ehsan , Farzanehfard Hosein
Published: February 2017

Efficiency, power density and electromagnetic interference (EMI) stand among the main concerns in power electronics and determine the quality of a power converter. To address the aforementioned concerns, this study proposes a cost effective passive soft‐switching technique using coupled inductor for pulse‐width modulation (PWM) converters. Through providing soft‐switching conditions, switching losses are reduced and the use of coupled inductor technique improves the power density. Since, the slope of voltage and current variations over time is reduced by the proposed passive soft‐switching technique, the EMI level is expected to reduce. This technique can be applied to a wide range of PWM converters, however, the analysis is focused on a soft‐switching boost converter to provide a framework. The experimental measurements of the realised 200 W boost converter show that the efficiency is improved by 2 and 3.8% as compared to a hard switching boost converter with and without an RCD snubber circuit, respectively. Moreover, the experimental EMI measurements indicate that with no external EMI filter, the proposed technique has reduced the main peak of EMI level by 8 dBµV (in comparison to its hard switching counterpart) which satisfies CISPR22 class A EMC standard limitation.
Optimal operation of hybrid microgrids for enhancing resiliency considering feasible islanding and survivability
Authors: Hussain Akhtar , Bui Van‐Hai , Kim Hak‐Man
Published: February 2017

Microgrids have the capability to enhance the resiliency of power systems by supplying local loads during emergency situations. However, the disturbance incident and clearance times cannot be predicted precisely. Therefore, this study is focused on enhancing the resiliency of hybrid microgrids considering feasible islanding and survivability of critical loads. The optimisation problem is decomposed into normal and emergency operation problems. In normal operation, unit commitment status of dispatchable generators and schedules of batteries are revised to ensure a feasible islanding following a disturbance event. In emergency operation, the decision between charging of batteries for future dispatch and feeding of lesser critical loads is considered. In addition, a strategy for minimisation of load curtailment during switching of scheduling windows is also considered. These two considerations can mitigate the curtailment of critical loads during the emergency period. Finally, a resiliency index is formulated to evaluate the performance of the proposed strategy during emergency operation. Numerical simulations have demonstrated the effectiveness of the proposed strategy for enhancing the resiliency of hybrid microgrids.
Modelling and simulation of large-scale polarized dust emission over the southern Galactic cap using the GASS Hi data
Authors: Ghosh T. , Boulanger F. , Martin P. G. , Bracco A. , Vansyngel F. , Aumont J. , Bock J. J. , Doré O. , Haud U. , Kalberla P. M. W. , Serra P.
Published: February 2017

The Planck survey has quantified polarized Galactic foregrounds and established that they are a main limiting factor in the quest for the cosmic microwave background B-mode signal induced by primordial gravitational waves during cosmic inflation. Accurate separation of the Galactic foregrounds therefore binds this quest to our understanding of the magnetized interstellar medium. The two most relevant empirical results from analysis of Planck data are line of sight depolarization arising from fluctuations of the Galactic magnetic field orientation and alignment of filamentary dust structures with the magnetic field at high Galactic latitude. Furthermore, Planck and H I emission data in combination indicate that most of the filamentary dust structures are in the cold neutral medium. The goal of this paper is to test whether these salient observational results, taken together, can account fully for the statistical properties of the dust polarization over a selected low column density region comprising 34% of the southern Galactic cap (b ≤ −30°). To do this, we construct a dust model that incorporates H I column density maps as tracers of the dust intensity structures and a phenomenological description of the Galactic magnetic field. By adjusting the parameters of the dust model, we were able to reproduce the Planck dust observations at 353GHz in the selected region. Realistic simulations of the polarized dust emission enabled by such a dust model are useful for testing the accuracy of component separation methods, studying non-Gaussianity, and constraining the amount of decorrelation with frequency.
GaiaData Release 1
Authors: Arenou F. , Luri X. , Babusiaux C. , Fabricius C. , Helmi A. , Robin A. C. , Vallenari A. , Blanco-Cuaresma S. , Cantat-Gaudin T. , Findeisen K. , Reylé C. , Ruiz-Dern L. , Sordo R. , Turon C. , Walton N. A. , Shih I.-C. , Antiche E. , Barache C. , Barros M. , Breddels M. , Carrasco J. M. , Costigan G. , Diakité S. , Eyer L. , Figueras F. , Galluccio L. , Heu J. , Jordi C. , Krone-Martins A. , Lallement R. , Lambert S. , Leclerc N. , Marrese P. M. , Moitinho A. , Mor R. , Romero-Gómez M. , Sartoretti P. , Soria S. , Soubiran C. , Souchay J. , Veljanoski J. , Ziaeepour H. , Giuffrida G. , Pancino E. , Bragaglia A.
Published: February 2017

Context.Before the publication of theGaiaCatalogue, the contents of the first data release have undergone multiple dedicated validation tests.

Aims.These tests aim to provide in-depth analysis of the Catalogue content in order to detect anomalies and individual problems in specific objects or in overall statistical properties, and either to filter them before the public release or to describe the different caveats on the release for an optimal exploitation of the data.

Methods.Dedicated methods using eitherGaiainternal data, external catalogues, or models have been developed for the validation processes. They test normal stars as well as various populations such as open or globular clusters, double stars, variable stars, and quasars. Properties of coverage, accuracy, and precision of the data are provided by the numerous tests presented here and are jointly analysed to assess the data release content.

Results.This independent validation confirms the quality of the published data,GaiaDR1 being the most precise all-sky astrometric and photometric catalogue to date. However, several limitations in terms of completeness, and astrometric or photometric quality are identified and described. Figures describing the relevant properties of the release are shown, and the testing activities carried out validating the user interfaces are also described. A particular emphasis is made on the statistical use of the data in scientific exploitation.
An in-depth spectroscopic examination of molecular bands from 3D hydrodynamical model atmospheres
Authors: Gallagher A. J. , Caffau E. , Bonifacio P. , Ludwig H.-G. , Steffen M. , Homeier D. , Plez B.
Published: February 2017

Context. Tighter constraints on metal-poor stars we observe are needed to better understand the chemical processes of the early Universe. Computing a stellar spectrum in 3D allows one to model complex stellar behaviours, which cannot be replicated in 1D.

Aims. We examine the effect that the intrinsic CNO abundances have on a 3D model structure and the resulting 3D spectrum synthesis.

Methods. Model atmospheres were computed in 3D for three distinct CNO chemical compositions using the CO5BOLD model atmosphere code, and their internal structures were examined. Synthetic spectra were computed from these models using Linfor3D and they were compared. New 3D abundance corrections for the G-band and a selection of UV OH lines were also computed.

Results. The varying CNO abundances change the metal content of the 3D models. This had an effect on the model structure and the resulting synthesis. However, it was found that the C/O ratio had a larger effect than the overall metal content of a model.

Conclusions. Our results suggest that varying the C/O ratio has a substantial impact on the internal structure of the 3D model, even in the hot turn-off star models explored here. This suggests that bespoke 3D models, for specific CNO abundances should be sought. Such effects are not seen in 1D at these temperature regimes.
Fulminant Influenza B Myocarditis in a Pediatric Patient
Authors: Censoplano Nina , Schumacher Kurt , McCormick Amanda
Published: February 2017

Influenza B is a common viral illness in childhood. We report a 5-year-old previously healthy girl admitted with facial edema that developed severe acute myocarditis from influenza B infection. As her clinical course progressed, she ultimately developed severe, acute heart failure requiring extracorporeal membrane oxygenation for support.
Fabrication of three-dimensional micro-nanofiber structures by a novel solution blow spinning device
Authors: Liang Feng , Fang Feiyu , Zeng Jun , Wang Zhifeng , Ou Weijun , Chen Xindu , Wu Peixuan , Wang Han , Zhang Lin
Published: February 2017

The fabrication of three-dimensional scaffolds has attracted more attention in tissue engineering. The purpose of this study is to explore a new method for the fabrication of three-dimensional micro-nanofiber structures by combining solution blow spinning and rotating collector. In this study, we successfully fabricated fibers with a minimum diameter of 200 nm and a three-dimensional structure with a maximum porosity of 89.9%. At the same time, the influence of various parameters such as the solvent volatility, the shape of the collector, the feed rate of the solution and the applied gas pressure were studied. It is found that solvent volatility has large effect on the formation of the three-dimensional shape of the structure. The shape of the collector affects the porosity and fiber distribution of the three-dimensional structure. The fiber diameter and fiber uniformity can be controlled by adjusting the solution feed rate and the applied gas pressure. It is feasible to fabricate high-quality three-dimensional micro-nanofiber structure by this new method, which has great potential in tissue engineering.
Merging symmetry projection methods with coupled cluster theory: Lessons from the Lipkin model Hamiltonian
Authors: Wahlen-Strothman Jacob M. , Henderson Thomas M. , Hermes Matthew R. , Degroote Matthias , Qiu Yiheng , Zhao Jinmo , Dukelsky Jorge , Scuseria Gustavo E.
Published: February 2017

Coupled cluster and symmetry projected Hartree-Fock are two central paradigms in electronic structure theory. However, they are very different. Single reference coupled cluster is highly successful for treating weakly correlated systems but fails under strong correlation unless one sacrifices good quantum numbers and works with broken-symmetry wave functions, which is unphysical for finite systems. Symmetry projection is effective for the treatment of strong correlation at the mean-field level through multireference non-orthogonal configuration interaction wavefunctions, but unlike coupled cluster, it is neither size extensive nor ideal for treating dynamic correlation. We here examine different scenarios for merging these two dissimilar theories. We carry out this exercise over the integrable Lipkin model Hamiltonian, which despite its simplicity, encompasses non-trivial physics for degenerate systems and can be solved via diagonalization for a very large number of particles. We show how symmetry projection and coupled cluster doubles individually fail in different correlation limits, whereas models that merge these two theories are highly successful over the entire phase diagram. Despite the simplicity of the Lipkin Hamiltonian, the lessons learned in this work will be useful for building an ab initio symmetry projected coupled cluster theory that we expect to be accurate in the weakly and strongly correlated limits, as well as the recoupling regime.
Diffusion of copolymers composed of monomers with drastically different friction factors in copolymer/homopolymer blends
Authors: Duranty Edward R. , Baschnagel Jörg , Dadmun Mark
Published: February 2017

Copolymers are commonly used as interface modifiers that allow for the compatibilization of polymer components in a blend. For copolymers to function as a compatibilizer, they must diffuse through the matrix of the blend to the interface between the two blend components. The diffusivity of a copolymer in a blend matrix therefore becomes important in determining good candidates for use as compatibilizers. In this work, coarse-grained Monte Carlo simulations using the bond fluctuation model modified with an overlap penalty have been developed to study the diffusive behavior of PS/PMMA random copolymers in a PMMA homopolymer blend. The simulations vary the connectivity between different monomers, the thermodynamic interactions between the monomers which manifest within a chain, and between copolymer and homopolymer matrix and define the monomer friction coefficient of each component independently, allowing for the determination of the combined effect of these parameters on copolymer chain diffusion. The results of this work indicate that PS-r-PMMA copolymer diffusion is not linearly dependent on the copolymer composition on a logarithmic scale, but its diffusion is a balance of the kinetics governed by the dominant motion of the faster styrene monomers and thermodynamics, which are governed by the concentration of styrene monomer within a given monomer’s local volume.
Spectroscopic and theoretical studies of ThCl and ThCl+
Authors: VanGundy Robert A. , Bartlett Joshua H. , Heaven Michael C. , Battey Samuel R. , Peterson Kirk A.
Published: February 2017

The electronic structures of ThCl and ThCl+ have been examined using laser induced fluorescence and two-photon ionization techniques. Rotationally resolved spectra, combined with the predictions from relativistic electronic structure calculations, show that the ground state of the neutral molecule is Th+(7s26d)Cl−, X2Δ3/2. Dispersed fluorescence spectra for ThCl revealed the ground state vibrational levels v = 0-10 and low energy electronic states that also originate from the atomic ion 7s26d configuration. Pulsed field ionization—zero kinetic energy photoelectron spectroscopy established an ionization energy (IE) for ThCl of 51 344(5) cm−1, and the ThCl+ vibrational term energies of the v = 1-3 levels. The zero-point level of the first electronically excited state was found at 949(2) cm−1. Comparisons with high-level theoretical results indicate that the ground and excited states are Th2+(7s6d)Cl− X3Δ1 and Th2+(7s2)Cl− Σ+1, respectively. Relativistic coupled cluster composite thermochemistry calculations yielded an IE within 1.2 kcal/mol of experiment and a bond dissociation energy (118.3 kcal/mol) in perfect agreement with previous experiments.
On the applicability of density dependent effective interactions in cluster-forming systems
Authors: Montes-Saralegui Marta , Kahl Gerhard , Nikoubashman Arash
Published: February 2017

We systematically studied the validity and transferability of the force-matching algorithm for computing effective pair potentials in a system of dendritic polymers, i.e., a particular class of ultrasoft colloids. We focused on amphiphilic dendrimers, macromolecules which can aggregate into clusters of overlapping particles to minimize the contact area with the surrounding implicit solvent. Simulations were performed for both the monomeric and coarse-grained models in the liquid phase at densities ranging from infinite dilution up to values close to the freezing point. The effective pair potentials for the coarse-grained simulations were computed from the monomeric simulations both in the zero-density limit (Φeff0) and at each investigated finite density (Φeff). Conducting the coarse-grained simulations with Φeff0 at higher densities is not appropriate as they failed at reproducing the structural properties of the monomeric simulations. In contrast, we found excellent agreement between the spatial dendrimer distributions obtained from the coarse-grained simulations with Φeff and the microscopically detailed simulations at low densities, where the macromolecules were distributed homogeneously in the system. However, the reliability of the coarse-grained simulations deteriorated significantly as the density was increased further and the cluster occupation became more polydisperse. Under these conditions, the effective pair potential of the coarse-grained model can no longer be computed by averaging over the whole system, but the local density needs to be taken into account instead.
Effects of salt or cosolvent addition on solubility of a hydrophobic solute in water: Relevance to those on thermal stability of a protein
Authors: Murakami Shota , Hayashi Tomohiko , Kinoshita Masahiro
Published: February 2017

The solubility of a nonpolar solute in water is changed upon addition of a salt or cosolvent. Hereafter, “solvent” is formed by water molecules for pure water, by water molecules, cations, and anions for water-salt solution, and by water and cosolvent molecules for water-cosolvent solution. Decrease and increase in the solubility, respectively, are ascribed to enhancement and reduction of the hydrophobic effect. Plenty of experimental data are available for the change in solubility of argon or methane arising from the addition. We show that the integral equation theory combined with a rigid-body model, in which the solute and solvent particles are modeled as hard spheres with different diameters, can reproduce the data for the following items: salting out by an alkali halide and salting in by tetramethylammonium bromide, increase in solubility by a monohydric alcohol, and decrease in solubility by sucrose or urea. The orders of cation or anion species in terms of the power of decreasing the solubility can also be reproduced for alkali halides. With the rigid-body model, the analyses are focused on the roles of entropy originating from the translational displacement of solvent particles. It is argued by decomposing the solvation entropy of a nonpolar solute into physically insightful constituents that the solvent crowding in the bulk is a pivotal factor of the hydrophobic effect: When the solvent crowding in the bulk becomes more serious, the effect is strengthened, and when it becomes less serious, the effect is weakened. It is experimentally known that the thermal stability of a protein is also influenced by the salt or cosolvent addition. The additions which decrease and increase the solubility of a nonpolar solute, respectively, usually enhance and lower the thermal stability. This suggests that the enhanced or reduced hydrophobic effect is also a principal factor governing the stability change. However, urea decreases the solubility but lowers the stability. Bromide and iodide ions decrease the solubility but lower the stability of a protein with a large, positive total charge. In these cases, the urea- or ion-protein van der Waals interaction energy as well as the hydrophobic effect needs to be taken into account in arguing the stability change. We also present a new view on the so-called Hofmeister series: We show how it is expressed when the change in hydrophobic effect dominates and how it is modified when other factors are also influential.
Corresponding-states behavior of SPC/E-based modified (bent and hybrid) water models
Authors: Weiss Volker C.
Published: February 2017

The remarkable and sometimes anomalous properties of water can be traced back at the molecular level to the tetrahedral coordination of molecules due to the ability of a water molecule to form four hydrogen bonds to its neighbors; this feature allows for the formation of a network that greatly influences the thermodynamic behavior. Computer simulations are becoming increasingly important for our understanding of water. Molecular models of water, such as SPC/E, are needed for this purpose, and they have proved to capture many important features of real water. Modifications of the SPC/E model have been proposed, some changing the H–O–H angle (bent models) and others increasing the importance of dispersion interactions (hybrid models), to study the structural features that set water apart from other polar fluids and from simple fluids such as argon. Here, we focus on the properties at liquid-vapor equilibrium and study the coexistence curve, the interfacial tension, and the vapor pressure in a corresponding-states approach. In particular, we calculate Guggenheim’s ratio for the reduced apparent enthalpy of vaporization and Guldberg’s ratio for the reduced normal boiling point. This analysis offers additional insight from a more macroscopic, thermodynamic perspective and augments that which has already been learned at the molecular level from simulations. In the hybrid models, the relative importance of dispersion interactions is increased, which turns the modified water into a Lennard-Jones-like fluid. Consequently, in a corresponding-states framework, the typical behavior of simple fluids, such as argon, is seen to be approached asymptotically. For the bent models, decreasing the bond angle turns the model essentially into a polar diatomic fluid in which the particles form linear molecular arrangements; as a consequence, characteristic features of the corresponding-states behavior of hydrogen halides emerge.
The collision of a hypervelocity massive projectile with free-standing graphene: Investigation of secondary ion emission and projectile fragmentation
Authors: Geng Sheng , Verkhoturov Stanislav V. , Eller Michael J. , Della-Negra Serge , Schweikert Emile A.
Published: February 2017

We present here the study of the individual hypervelocity massive projectiles (440–540 keV, 33–36 km/s Au4004+ cluster) impact on 1-layer free-standing graphene. The secondary ions were detected and recorded separately from each individual impact in the transmission direction using a time-of-flight mass spectrometer. We observed C1-10± ions emitted from graphene, the projectiles which penetrated the graphene, and the Au1-3± fragment ions in mass spectra. During the projectile-graphene interaction, the projectile loses ∼15% of its initial kinetic energy (∼0.18 keV/atom, 72 keV/projectile). The Au projectiles are neutralized when approaching the graphene and then partially ionized again via electron tunneling from the hot rims of the holes on graphene, obtaining positive and negative charges. The projectile reaches an internal energy of ∼450–500 eV (∼4400–4900 K) after the impact and then undergoes a ∼90-100 step fragmentation with the ejection of Au1 atoms in the experimental time range of ∼0.1 μs.
Enhanced dynamics simulation and threshold analysis of multipaction in the ferrite microwave component
Authors: Li Y. , Cui W. Z. , He Y. N. , Wang X. B. , Hu T. C. , Wang D.
Published: February 2017

Multipactor discharge between dielectric and metal was investigated and experimentally verified for the first time. Moreover, multipaction electron evolution laws in the complex ferrite component were revealed, and discharge breakdown threshold was analyzed. Through reasonable approximation and by establishing the equivalent analytical model, the effects of the external static magnetic field and charge accumulation were investigated, and transient electronic trajectory was obtained. Based on the electromagnetic particle-in-cell technology, the three dimensional simulation method of electron evolution in complex ferromagnetic microwave components was implemented. The discharge threshold was obtained through the long term evolution of field to electron and electron to field interactions and verified by multipactor measurement on the circulator for the first time. Instead of the steady field condition, the steady particle condition was proposed for the threshold prediction, exhibiting great potential in the space industry application. It is demonstrated that for ferrite dielectric-metal multipaction, the phase focusing process was prolonged, and the traditional prediction criteria for the threshold analysis were invalid due to the existence of the external magnetic field and highly inhomogeneous field distribution.
Transport properties of exchange biased mesoscale wires
Authors: Delles J. T. , Harrison D. C. , Endean Dan , Dahlberg E. Dan
Published: February 2017

The magnetic field dependence of the anisotropic magneto-resistance (AMR) was measured in exchange biased straight and zigzag CoFe wires. The field dependent AMR of the zigzag wires is modeled as a superposition of the AMR of the straight wires. Micromagnetic simulations of the system provided additional information on the magnetization in the straight and zigzag wires.
Synaptic plasticity and oscillation at zinc tin oxide/silver oxide interfaces
Authors: Murdoch Billy J. , McCulloch Dougal G. , Partridge James G.
Published: February 2017

Short-term plasticity, long-term potentiation, and pulse interval dependent plasticity learning/memory functions have been observed in junctions between amorphous zinc-tin-oxide and silver-oxide. The same junctions exhibited current-controlled negative differential resistance and when connected in an appropriate circuit, they behaved as relaxation oscillators. These oscillators produced voltage pulses suitable for device programming. Transmission electron microscopy, energy dispersive X-ray spectroscopy, and electrical measurements suggest that the characteristics of these junctions arise from Ag+/O− electromigration across a highly resistive interface layer. With memory/learning functions and programming spikes provided in a single device structure, arrays of similar devices could be used to form transistor-free neuromorphic circuits.
Phonon conduction in GaN-diamond composite substrates
Authors: Cho Jungwan , Francis Daniel , Altman David H. , Asheghi Mehdi , Goodson Kenneth E.
Published: February 2017

The integration of strongly contrasting materials can enable performance benefits for semiconductor devices. One example is composite substrates of gallium nitride (GaN) and diamond, which promise dramatically improved conduction cooling of high-power GaN transistors. Here, we examine phonon conduction in GaN-diamond composite substrates fabricated using a GaN epilayer transfer process through transmission electron microscopy, measurements using time-domain thermoreflectance, and semiclassical transport theory for phonons interacting with interfaces and defects. Thermoreflectance amplitude and ratio signals are analyzed at multiple modulation frequencies to simultaneously extract the thermal conductivity of GaN layers and the thermal boundary resistance across GaN-diamond interfaces at room temperature. Uncertainties in the measurement of these two properties are estimated considering those of parameters, including the thickness of a topmost metal transducer layer, given as an input to a multilayer thermal model, as well as those associated with simultaneously fitting the two properties. The volume resistance of an intermediate, disordered SiN layer between the GaN and diamond, as well as a presence of near-interfacial defects in the GaN and diamond, dominates the measured GaN-diamond thermal boundary resistances as low as 17 m2 K GW−1. The GaN thermal conductivity data are consistent with the semiclassical phonon thermal conductivity integral model that accounts for the size effect as well as phonon scattering on point defects at concentrations near 3 × 1018 cm−3.
Longitudinal dielectric function and dispersion relation of electrostatic waves in relativistic plasmas
Authors: Touil B. , Bendib A. , Bendib-Kalache K.
Published: February 2017

The longitudinal dielectric function is derived analytically from the relativistic Vlasov equation for arbitrary values of the relevant parameters z=mc2/T, where m is the rest electron mass, c is the speed of light, and T is the electron temperature in energy units. A new analytical approach based on the Legendre polynomial expansion and continued fractions was used. Analytical expression of the electron distribution function was derived. The real part of the dispersion relation and the damping rate of electron plasma waves are calculated both analytically and numerically in the whole range of the parameter z. The results obtained improve significantly the previous results reported in the literature. For practical purposes, explicit expressions of the real part of the dispersion relation and the damping rate in the range z>30 and strongly relativistic regime are also proposed.
The effects of temperature on optical properties of InGaN/GaN multiple quantum well light-emitting diodes
Authors: Li Yi , Zhu Youhua , Huang Jing , Deng Honghai , Wang Meiyu , Yin HaiHong
Published: February 2017

The effects of temperature on the optical properties of InGaN/GaN quantum well (QW) light-emitting diodes have been investigated by using the six-by-six K-P method taking into account the temperature dependence of band gaps, lattice constants, and elastic constants. The numerical results indicate that the increase of temperature leads to the decrease of the spontaneous emission rate at the same injection current density due to the redistribution of carrier density and the increase of the non-radiative recombination rate. The product of Fermi-Dirac distribution functions of electron fcn and hole (1−fvUm) for the transitions between the three lowest conduction subbands (c1–c3) and the top six valence subbands (v1–v6) is larger at the lower temperature, which indicates that there are more electron-hole pairs distributed on the energy levels. It should be noted that the optical matrix elements of the inter-band transitions slightly increase at the higher temperature. In addition, the internal quantum efficiency of the InGaN/GaN QW structure is evidently decreased with increasing temperature.
Enhanced charge separation at 2D MoS2/ZnS heterojunction: KPFM based study of interface photovoltage
Authors: Sharma Intu , Mehta B. R.
Published: February 2017

Two dimensional (2D) MoS2/ZnS heterojunctions with MoS2 thickness varying from monolayer to bulk have been prepared by sulfurization of a controlled thickness of Mo deposited on the ZnS thin films. Kelvin probe force microscopy measurements on MoS2/ZnS junction having varying thicknesses of MoS2 layers are carried out in the surface and junction modes, under white light exposure. Differences in the surface potential values of the surface and junction modes represent interface photovoltages at heterojunctions. Enhanced interface photovoltage is observed in junctions having the mono and few layer MoS2 in comparison to bulk MoS2 layer. This suggests the active participation of 2D MoS2 layer in photon absorption and charge separation processes taking place close to the junction. The present study is an effort towards the integration of 2D layered materials with 3D semiconductors, which may be advantageous for the development of 2D material based optoelectronic devices.
Low-frequency ultrasonic Bessel-like collimated beam generation from radial modes of piezoelectric transducers
Authors: Chillara Vamshi Krishna , Pantea Cristian , Sinha Dipen N.
Published: February 2017

We present a very simple approach to generate a collimated ultrasonic beam that exploits the natural Bessel-like vibration pattern of the radial modes of a piezoelectric disc with lateral clamping. This eliminates the need for the conventional annular Bessel pattern of the electrodes with individual electrode excitation on the piezo-disc, thus simplifying the transducer design. Numerical and experimental studies are carried out to investigate the Bessel-like vibration patterns of these radial modes showing an excellent agreement between these two studies. Measured ultrasonic beam-profiles in water from the radial modes confirm the profile to be a Bessel beam. Collimated beam generation from radial modes is investigated using a coupled electromechanical finite-element model. It is found that clamping the lateral edges of piezoelectric transducers results in a high-degree of collimation with practically no side-lobes similar to a parametric array beam. Ultrasonic beam-profile measurements in water with both free and clamped piezoelectric transducer are presented. The collimated beam generation using the present technique of using the laterally clamped radial modes finds significant applications in low-frequency imaging through highly attenuating materials.
Impact of local atomic stress on oxygen segregation at tilt boundaries in silicon
Authors: Ohno Yutaka , Inoue Kaihei , Fujiwara Kozo , Kutsukake Kentaro , Deura Momoko , Yonenaga Ichiro , Ebisawa Naoki , Shimizu Yasuo , Inoue Koji , Nagai Yasuyoshi , Yoshida Hideto , Takeda Seiji , Tanaka Shingo , Kohyama Masanori
Published: February 2017

Using the atom probe tomography, transmission electron microscopy, and ab initio calculations, we investigate the three-dimensional distributions of oxygen atoms segregating at the typical large-angle grain boundaries (GBs) (Σ3{111}, Σ9{221}, Σ9{114}, Σ9{111}/{115}, and Σ27{552}) in Czochralski-grown silicon ingots. Oxygen atoms with a covalent radius that is larger than half of the silicon's radius would segregate at bond-centered positions under tensile stresses above about 2 GPa, so as to attain a more stable bonding network by reducing the local stresses. The number of oxygen atoms segregating in a unit GB area NGB (in atoms/nm2) is hypothesized to be proportional to both the number of the tensilely-stressed positions in a unit boundary area nbc and the average concentration of oxygen atoms around the boundary [Oi] (in at. %) with NGB∼50nbc[Oi]. This indicates that the probability of oxygen atoms at the segregation positions would be, on average, fifty times larger than in bond-centered positions in defect-free regions.
Female sociality and sexual conflict shape offspring survival in a Neotropical primate
Authors: Kalbitzer Urs , Bergstrom Mackenzie L. , Carnegie Sarah D. , Wikberg Eva C. , Kawamura Shoji , Campos Fernando A. , Jack Katharine M. , Fedigan Linda M.
Published: February 2017

Significance

In group-living mammals, infants of females with strong social relationships sometimes exhibit higher survivorship than infants of less social females, a finding that holds true in our study population of wild white-faced capuchin monkeys. However, as in many mammals, new alpha male capuchins often kill young infants sired by other males. Our long-term research shows that infants of highly social females are at greater risk of dying or disappearing during periods of alpha male replacements than infants of less social females. These findings indicate that new alpha males are more likely to target the infants of more social, and therefore central, females. Our study provides evidence that female sociality can negatively affect offspring survival by increasing the likelihood of infanticide.
Functional importance of stripping in NFκB signaling revealed by a stripping-impaired IκBα mutant
Authors: Dembinski Holly E. , Wismer Kevin , Vargas Jesse D. , Suryawanshi Gajendra W. , Kern Nadja , Kroon Gerard , Dyson H. Jane , Hoffmann Alexander , Komives Elizabeth A.
Published: February 2017

Significance

Stress-response transcription factors turn on hundreds of genes, and their activity must be turned off completely and quickly. The inhibitor protein IκBα turns off NFκB by forming a transient ternary complex with the NFκB–DNA complex and then promoting DNA dissociation (molecular stripping). Here we report a mutant IκBα that is impaired in its ability to strip NFκB from DNA. The mutant forms a more stable ternary complex, and biophysical characterization shows what IκBα looks like “in the act of stripping.” We also show in single-cell nuclear export assays that the decrease in the rate of DNA dissociation from the mutant ternary complex matches the decrease in the rate of nuclear NFκB export in cells.
A distinct subset of plasmacytoid dendritic cells induces activation and differentiation of B and T lymphocytes
Authors: Zhang Hong , Gregorio Josh D. , Iwahori Toru , Zhang Xiangyue , Choi Okmi , Tolentino Lorna L. , Prestwood Tyler , Carmi Yaron , Engleman Edgar G.
Published: February 2017

Significance

Plasmacytoid dendritic cells (pDCs) are specialized white blood cells responsible for a wide range of immune functions, most notably production of the antiviral factor, type I interferon. We have discovered a previously unknown population of pDCs in human blood, bone marrow, and tonsil that is morphologically, phenotypically, and genetically distinct from most pDCs. These cells, which can be identified based on their expression of CD2, CD5, and CD81 on their surface, fail to produce type I interferon, yet they strongly activate B and T lymphocytes. A functionally and phenotypically similar population of pDCs is present in mice. These pDCs likely play an important role in the immune response.
Probing equilibrium of molecular and deprotonated water on TiO
2
(110)
Authors: Wang Zhi-Tao , Wang Yang-Gang , Mu Rentao , Yoon Yeohoon , Dahal Arjun , Schenter Gregory K. , Glezakou Vassiliki-Alexandra , Rousseau Roger , Lyubinetsky Igor , Dohnálek Zdenek
Published: February 2017

Significance

Understanding how water binds and dissociates on surfaces has broad implications in a vast range of physical and chemical processes. The relative stability of molecularly and dissociatively bound water has been debated for decades on many oxide surfaces, but it has never been successfully measured. Our study describes unique instrumentation, direct measurements, and a state-of-the-art computation and theory approach that yield a detailed kinetic and dynamic description of water deprotonation equilibrium on TiO
2
(110), a prototypical surface commonly used in mechanistic studies of photocatalytic water splitting. This unique study demonstrates that the molecularly bound water on TiO
2
(110) is preferred over the surface-bound hydroxyls by only 0.035 eV.
ACSS2-mediated acetyl-CoA synthesis from acetate is necessary for human cytomegalovirus infection
Authors: Vysochan Anna , Sengupta Arjun , Weljie Aalim M. , Alwine James C. , Yu Yongjun
Published: February 2017

Significance

Viruses rely completely on host cell metabolism to provide the building blocks and energy required for producing progeny virions. Infection by human cytomegalovirus (HCMV) induces significant alterations in glucose metabolism by increasing glucose uptake and glycolysis as well as redirecting glucose carbon to support the synthesis of biomolecules such as lipids. The significance of acetate as a nutrient has been ignored for a long period. Our studies show that glucose carbon can be converted to acetate and used to make cytosolic acetyl-CoA by acetyl-CoA synthetase short-chain family member 2 (ACSS2) for lipid synthesis, which is important for HCMV-induced lipogenesis and the viral growth. The study provides greater understanding of HCMV pathogenesis and suggests strategies to develop antiviral therapies.
Modular assembly of thick multifunctional cardiac patches
Authors: Fleischer Sharon , Shapira Assaf , Feiner Ron , Dvir Tal
Published: February 2017

Significance

Heart disease is the primary cause of death in the United States. Cardiac tissue engineering has evolved with the goal of creating heart patches to treat end-stage patients. Here, we report on a bottom-up approach to assemble a modular cardiac patch that consists of various tissue layers, each performing a different function. One layer was designed to accommodate cardiac cells and promote their organization into a contracting tissue. Another layer enables the organization of endothelial cells into blood vessels, and layers with microparticulate systems enable the controlled release of different biofactors affecting the engineered tissue or the host. We have shown that the patch can be assembled from its building blocks just before transplantation and can perform in the body.
Cell population structure prior to bifurcation predicts efficiency of directed differentiation in human induced pluripotent cells
Authors: Bargaje Rhishikesh , Trachana Kalliopi , Shelton Martin N. , McGinnis Christopher S. , Zhou Joseph X. , Chadick Cora , Cook Savannah , Cavanaugh Christopher , Huang Sui , Hood Leroy
Published: February 2017

Significance

Induced pluripotent stem cells (iPSCs) open new possibilities for generating personalized disease models and drug testing. However, iPSC differentiation to a specific cell type can take weeks to complete, delaying the optimization process (maximize yield of desired cell types) for each patient’s iPSC. This task can be accelerated if the destination cell type can be determined early during cell lineage trajectory before cells manifest the desired phenotype. Our results indicate such a possibility: by quantifying the cell population structure during a critical state transition, we identified key regulators of lineages commitment and predicted the percentage of desired cell types for several protocol variations 2 wk in advance.
From confinement to community service
Authors: Rossato Linda
Published: February 2017

This paper presents a spin-off study from the research project In MedIO PUER(I), launched at the University of Bologna in 2007 (see Antonini 2010a; Antonini 2010b; Cirillo et al. 2010; Bucaria & Rossato 2010; Antonini this volume), and sets out to investigate the under-researched phenomenon of language and cultural brokering among migrant inmates. In countries such as Italy, where immigration is still a recent experience and resources for institutional interpreting are scarce even in ordinary public contexts, professional language services are virtually non-existent in secluded environments such as prisons. Foreign inmates and jail personnel face linguistic problems that they tend to handle through spontaneous forms of mediation: a convicted migrant, who is fluent in Italian, may act as a mediator between fellow-country inmates with poor knowledge of the host language and jail officers. This form of language and cultural brokering is a common form of ad hoc interpreting that responds to the communication needs of both inmates and detention institutions. This paper sets out to map the phenomenon and to investigate whether this practice has an impact on inmates’ self-perception and rehabilitation process.