bluuebunny/crossref_metadata_2025 huggingface dataset:
A fused silica Cherenkov radiator for high precision time-of-flight measurement of DT γ and neutron spectra (invited)
Authors: Moore A. S. , Schlossberg D. J. , Hartouni E. P. , Sayre D. , Eckart M. J. , Hatarik R. , Barbosa F. , Root J. , Waltz C. , Beeman B. , Rubery M. S. , Grim G. P.
Published: October 2018

A fused silica Cherenkov radiator has been implemented at the National Ignition Facility to provide a new high precision measurement of the time-of-flight spectrum of 14.1 MeV DT fusion neutrons. This detector enables a high precision (<30 ps) co-registered measurement of both a thresholded γ-ray and a neutron spectrum on a single record. Other methods typically require γ and neutron signals to be co-registered via other diagnostics and/or dedicated timing experiments. Analysis of the co-registered γ and neutron signals allows precise extraction of the mean neutron energy and bulk hot-spot velocity, both of which were not possible with prior scintillator technologies. Initial measurements demonstrate the feasibility of this measurement and indicate that combined detection of neutrons and γ-rays on multiple lines-of-sight should enable the bulk vector velocity of the implosion hot-spot to be determined to ≈5 km/s and reduced uncertainty in the spectral width ≈0.1 keV.
Dual laser holography for in situ measurement of plasma facing component erosion (invited)
Authors: Biewer T. M. , Sawyer J. C. , Smith C. D. , Thomas C. E.
Published: October 2018

A digital holography (DH) surface erosion/deposition diagnostic is being developed for 3D imaging of plasma facing component surfaces in situ and in real time. Digital holography is a technique that utilizes lasers reflected from a material surface to form an interferogram, which carries information about the topology of the surface when reconstructed. As described in this paper, dual CO2 lasers at 9.271 and 9.250 μm wavelengths illuminate the interrogated surface (at a distance of ∼1 m) in a region of ∼1 cm × 1 cm. The surface feature resolution is ∼0.1 mm in the plane of the surface, and the depth resolution ranges from ∼0.0001 to ∼2 mm perpendicular to the surface. The depth resolution lower limit is set by single-laser and detector optical limitations, while the upper limit is determined by 2π phase ambiguity of the dual-laser synthetic wavelength. Measurements have been made “on the bench” to characterize the single-laser and dual-laser DH configurations utilizing standard resolution targets and material targets that were previously exposed to high flux plasmas in either the Prototype Material Plasma Exposure eXperiment (Proto-MPEX) or the electro-thermal (ET) arc source. Typical DH measurements were made with 0.03 ms integration with an IR camera that can be framed at rates approaching 1.5 kHz. The DH diagnostic system is progressing toward in situ measurements of plasma erosion/deposition either on Proto-MPEX or the ET arc source.
Reversible and magnetically unassisted voltage-driven switching of magnetization in FeRh/PMN-PT
Authors: Fina Ignasi , Quintana Alberto , Martí Xavier , Sánchez Florencio , Foerster Michael , Aballe Lucia , Sort Jordi , Fontcuberta Josep
Published: October 2018

Reversible control of magnetization by electric fields without assistance from a subsidiary magnetic field or electric current could help reduce the power consumption in spintronic devices. When increasing temperature above room temperature, FeRh displays an uncommon antiferromagnetic to ferromagnetic phase transition linked to a unit cell volume expansion. Thus, using the strain exerted by an adjacent piezoelectric layer, the relative amount of antiferromagnetic and ferromagnetic regions can be tuned by an electric field applied to the piezoelectric material. Indeed, large variations in the saturation magnetization have been observed when straining FeRh films grown on suitable piezoelectric substrates. In view of its applications, the variations in the remanent magnetization rather than those of the saturation magnetization are the most relevant. Here, we show that in the absence of any bias external magnetic field, permanent and reversible magnetization changes as high as 34% can be induced by an electric field, which remain after this has been zeroed. Bulk and local magnetoelectric characterization reveals that the fundamental reason for the large magnetoelectric response observed at remanence is the expansion (rather than the nucleation) of ferromagnetic nanoregions.
Probing the structures and bonding of auropolyynes, Au—(C≡C)n—Au− (n = 1–3), using high-resolution photoelectron imaging
Authors: León Iker , Ruipérez Fernando , Ugalde Jesus M. , Wang Lai-Sheng
Published: October 2018

We report an investigation of a series of auropolyynes, Au—(C≡C)n—Au− (n = 1–3), using high-resolution photoelectron imaging and ab initio calculations. Vibrationally resolved photoelectron spectra are obtained, allowing the electron affinities of Au—(C≡C)n—Au to be accurately measured as 1.651(1), 1.715(1), and 1.873(1) eV for n = 1–3, respectively. Both the Au—C symmetric stretching and a bending vibrational frequency are observed for each neutral auropolyyne. Theoretical calculations find that the ground state of Au2C2− has a linear acetylenic Au—C≡C—Au− structure, whereas the asymmetric Au—Au—C≡C− structure is a low-lying isomer. However, for Au2C4− and Au2C6−, our calculations show that the asymmetric Au—Au—(C≡C)n− isomers are the global minima and the Au—(C≡C)n—Au− symmetric structures become low-lying isomers. All the asymmetric Au—Au—(C≡C)n− isomers are found computationally to have much higher electron binding energies and are not accessible at the detachment photon energies used in the current study. For neutral Au2C2n, the Au—(C≡C)n—Au auropolyyne structures are found to be the global minima for n = 1–3. The electronic structures and bonding for Au—(C≡C)n—Au (n = 1–3) are compared with the corresponding Au—(C≡C)n and Au—(C≡C)n—H species.
MIRRORS: A MATLAB® GUI for temperature measurement by multispectral imaging radiometry
Authors: Lord O. T. , Wang W.
Published: October 2018

MultIspectRal imaging RadiOmetRy Software (MIRRORS) is an open source MATLAB based Graphical User Interface (GUI) designed to automatically process images generated from a four colour multispectral imaging radiometry system for the temperature measurement of samples heated in a diamond anvil cell. The GUI can work in either a live mode (during an experiment) or a post-processing mode and performs background subtraction, spatial correlation, and thermal calibration of the data before producing maps of temperature, emissivity, and their associated uncertainties, an image difference map (i.e., the change in the shape of the temperature field), and a variety of other visualisations derived from them. We describe the distribution, system requirements, and required hardware specific code modifications necessary to setup MIRRORS. We also describe the workflow of the software and its underlying methodologies and provide an example output as well as the results of benchmarking against a traditional spectroradiometric system of known accuracy.
Broadband acoustic energy harvesting metasurface with coupled Helmholtz resonators
Authors: Liu Guang-Sheng , Peng Yao-Yin , Liu Ming-Hao , Zou Xin-Ye , Cheng Jian-Chun
Published: October 2018

We report a broadband acoustic energy harvesting metasurface consisting of periodic arrangements of coupled Helmholtz resonators. Theoretical analysis and numerical and experimental results show that a high output voltage can be obtained at a wide band (460 Hz–680 Hz) under the push-pull effect on the piezoelectric composite sheet (PCS) between the two coupled cavities, which is because the acoustic pressure phases in the two coupled cavities are nearly opposite to each other. Each output can be directly connected in parallel without any rectification circuit because the output voltage from every PCS has the same phase on account of the symmetry of the proposed metasurface. The proposed design has an efficient and easy-to-integrate structure, and it can be used in broad applications for acoustic energy harvesting devices and acoustic insulators.
Steady-state microwave conductivity reveals mobility-lifetime product in methylammonium lead iodide
Authors: Labram John G. , Perry Erin E. , Venkatesan Naveen R. , Chabinyc Michael L.
Published: October 2018

Many time-resolved techniques to study charge carrier recombination involve pulsed high-power optical excitation and photo-generated carrier densities many orders of magnitude higher than present under typical solar cell operating conditions. In this report, we demonstrate a steady-state contactless microwave conductivity technique to evaluate the photoconductivity of carriers in semiconductors at low illumination intensity, as a function of optical power density. We studied characteristics of both thin films and single crystals of a hybrid halide perovskite compound, methylammonium lead iodide (MAPbI3). The aggregate mobility-lifetime product of majority and minority carriers in thin films of MAPbI3 was determined and found to be highly-dependent on incident optical power density, even at sub-1-sun illumination intensities, and attributed to trap states within the films.
Particle-based fluid dynamics: Comparison of different Bhatnagar-Gross-Krook models and the direct simulation Monte Carlo method for hypersonic flows
Authors: Pfeiffer M.
Published: October 2018

The Bhatnagar-Gross-Krook (BGK) model and its extensions (ellipsoidal statistical BGK, Shakhov BGK, and unified BGK) are used in particle-based fluid dynamics and compared with the Direct Simulation Monte Carlo (DSMC) method. To this end, different methods are investigated that allow efficient sampling of the Shakhov and the unified target distribution functions. As a consequence, particle simulations based on the Shakhov BGK and unified BGK models are possible in an efficient way. Furthermore, different energy conservation schemes are tested for the BGK models. It is shown that the choice of the energy conservation scheme has a major impact on the quality of the results for each model. The models are verified with a Couette flow problem at different Knudsen numbers and wall velocities. Furthermore, the models are compared with the DSMC results of a hypersonic flow around a 70° blunted cone. It is shown that the unified BGK model is able to reproduce rarefied gas phenomena. Furthermore, it is shown that the difference in the reproduction of the shock structure is not significant between the ellipsoidal statistical BGK and Shakhov BGK models for the flow around a 70° blunted cone and significantly depends on the energy conservation method. The choice of the energy conservation method is especially crucial for the Shakhov model whereas the ellipsoidal statistical BGK model is much more robust concerning the energy conservation scheme. Additionally, a computational time study is performed to show the efficiency of BGK-based simulations for low Knudsen number flows compared with DSMC.
Performance analysis of nanostructured Peltier coolers
Authors: Singha Aniket , Muralidharan Bhaskaran
Published: October 2018

Employing non-equilibrium quantum transport models, we investigate the details and operating conditions of nano-structured Peltier coolers embedded with an energy filtering barrier. Our investigations point out non-trivial aspects of Peltier cooling which include an inevitable trade-off between the cooling power and the coefficient of performance, the coefficient of performance being high at a low voltage bias and subsequently deteriorating with increasing voltage bias. We point out that there is an optimum energy barrier height for nanowire Peltier coolers at which the cooling performance is optimized. However, for bulk Peltier coolers, the cooling performance is enhanced with the height of the energy filtering barrier. Exploring further, we point out that a degradation in cooling performance with respect to bulk is inevitable as a single moded nanowire transitions to a multi-moded one. The results discussed here can provide theoretical insights into optimal design of nano Peltier coolers.
Fundamental exciton transitions in SiO2/Si/SiO2 cylindrical core/shell quantum dot
Authors: El-Yadri M. , Feddi E. , Aghoutane N. , El Aouami A. , Radu A. , Dujardin F. , Nguyen Chuong V. , Phuc Huynh V. , Duque C. A.
Published: October 2018

This paper reports the numerical investigation of the quantum confinement effects on excitons in a Si cylindrical core/shell quantum dots. Using the effective-mass approximation and considering a variational technique, we have calculated the exciton ground state binding energy as functions of the shell size in order to study the behavior of the confined exciton into the region of a thin shell with rigid walls. Our results show that the core-shell sizes have a remarkable influence on the electron-hole interaction, which leads to a significant impact on the binding and the optical photoluminescence energies of exciton. Also, we found that the exciton binding energy is higher for the small shell sizes. The effects caused by quantum confinement in such quantum dot nanostructures offer an alternative way of tuning the excitonic transitions in optoelectronic semiconducting devices.
Formation of field-reversed configuration using an in-vessel odd-parity rotating magnetic field antenna in a linear device
Authors: Shi Peiyun , Ren Baoming , Zheng Jian , Sun Xuan
Published: October 2018

A Field-Reversed Configuration (FRC) is formed by an in-vessel odd-parity rotating magnetic field (RMF) antenna in a tandem mirror device, Keda mirror with axisymmetricity. The 40-cm diameter antenna is fed independently by four IGBT-based power units with an output current of 1500 A each at 84 kHz, and their phases are adjustable to launch odd or even parity RMFs. A medium-sized washer gun is utilized to generate a highly ionized seed hydrogen plasma. Driven by RMF, the resultant FRC is formed with a separatrix radius of ∼17 cm, external field of ∼50 G, and trapped poloidal flux of ∼0.15 mWb. The formation process of FRCs is evidenced by the measurement of an array of internal two-dimensional probes; a comparison with the rigid rotor model is presented in this paper. In addition, substantial toroidal electron current is found to be driven, despite the partial RMF penetration. Moreover, the dependence of the driven current on the antenna current is reported and is found to be consistent with the RMF current driving model.
Observation of extreme ultraviolet light emission from an expanding plasma jet with multiply charged argon or xenon ions
Authors: Shalashov A. G. , Vodopyanov A. V. , Abramov I. S. , Sidorov A. V. , Gospodchikov E. D. , Razin S. V. , Chkhalo N. I. , Salashchenko N. N. , Glyavin M. Yu. , Golubev S. V.
Published: October 2018

We report on the first direct demonstration of the possibility to generate extreme ultraviolet (EUV) radiation with a freely expanding jet of dense plasma with multiply charged ions supported by high-power microwaves. The detected emission power is about 20 W at 18–50 nm for argon and xenon and 0.3 W at 13–17 nm for xenon. The discharge with a peak electron density of up to 3×1016  cm−3 and a characteristic size of 150 μm is supported by the focused radiation of a recently developed gyrotron with unique characteristics, having a 250 kW output power at 250 GHz and operated in a relatively long (50  μs) pulse mode. Up-scaling of these experimental results gives grounds for the development of a point-like kilowatt-level EUV source for high-resolution lithography, which is able to meet the requirements of the microelectronics industry.
Perspective: Strong microwave photon-magnon coupling in multiresonant dielectric antennas
Authors: Maksymov Ivan S.
Published: October 2018

Achieving quantum-level control over electromagnetic waves, magnetisation dynamics, vibrations, and heat is invaluable for many practical applications and possible by exploiting the strong radiation-matter coupling. Most of the modern strong microwave photon-magnon coupling developments rely on the integration of metal-based microwave resonators with a magnetic material. However, it has recently been realised that all-dielectric resonators made of or containing magneto-insulating materials can operate as a standalone strongly coupled system characterised by low dissipation losses and strong local microwave field enhancement. Here, after a brief overview of recent developments in the field, I discuss examples of such dielectric resonant systems and demonstrate their ability to operate as multiresonant antennas for light, microwaves, magnons, sound, vibrations, and heat. This multiphysics behavior opens up novel opportunities for the realisation of multiresonant coupling such as, for example, photon-magnon-phonon coupling. I also propose several novel systems in which strong photon-magnon coupling in dielectric antennas and similar structures is expected to extend the capability of existing devices or may provide an entirely new functionality. Examples of such systems include novel magnetofluidic devices, high-power microwave power generators, and hybrid devices exploiting the unique properties of electrical solitons.
Room-temperature single dopant atom quantum dot transistors in silicon, formed by field-emission scanning probe lithography
Authors: Durrani Zahid , Jones Mervyn , Abualnaja Faris , Wang Chen , Kaestner Marcus , Lenk Steve , Lenk Claudia , Rangelow Ivo W. , Andreev Aleksey
Published: October 2018

Electrical operation of room-temperature (RT) single dopant atom quantum dot (QD) transistors, based on phosphorous atoms isolated within nanoscale SiO2 tunnel barriers, is presented. In contrast to single dopant transistors in silicon, where the QD potential well is shallow and device operation limited to cryogenic temperature, here, a deep (∼2 eV) potential well allows electron confinement at RT. Our transistors use ∼10 nm size scale Si/SiO2/Si point-contact tunnel junctions, defined by scanning probe lithography and geometric oxidation. “Coulomb diamond” charge stability plots are measured at 290 K, with QD addition energy ∼0.3 eV. Theoretical simulation gives a QD size of similar order to the phosphorous atom separation ∼2 nm. Extraction of energy states predicts an anharmonic QD potential, fitted using a Morse oscillator-like potential. The results extend single-atom transistor operation to RT, enable tunneling spectroscopy of impurity atoms in insulators, and allow the energy landscape for P atoms in SiO2 to be determined.
Analytical expressions for the ferromagnetic resonance mode intensity and linewidths for a weakly coupled magnetic tunnel junction system
Authors: Layadi A.
Published: October 2018

Ferromagnetic Resonance mode intensity, I, field linewidth, ΔH, and frequency linewidth, Δf, have been investigated for a weakly coupled magnetic tunnel junction (MTJ) system. The analysis applies for a coupled trilayer, i.e., two ferromagnetic thin films separated by a non magnetic thin film and for a MTJ system consisting of the trilayer and an antiferromagnetic layer. For this particular weakly coupled system, analytical expressions for I, ΔH, and Δf have been determined. The linewidth expressions can be separated into the parts characterizing the individual thin films and magnetic coupling dependent parts; the mode linewidths can be viewed as those of uncoupled thin films with equivalent damping parameters. The intensity and the linewidths are discussed for different applied magnetic fields, for the saturated and unsaturated systems, and for the two types of coupling. It will be shown how the mode intensity behavior can be used as a probe to distinguish the ferromagnetic from the antiferromagnetic coupling.
A theoretical study of energy transfer in Ar(1S) + SO2(X̃1A′) collisions: Cross sections and rate coefficients for vibrational transitions
Authors: da Silva Ramon S. , Ballester Maikel Y.
Published: October 2018

Vibrational transitions, induced by collisions between rare-gas atoms and molecules, play a key role in many problems of interest in physics and chemistry. A theoretical investigation of the translation-to-vibration (T-V) energy transfer process in argon atom and sulfur dioxide molecule collisions is presented here. For such a purpose, the framework of the quasi-classical trajectory (QCT) methodology was followed over the range of translational energies 2 ≤ Etr/kcal mol−1 ≤ 100. A new realistic potential energy surface (PES) for the ArSO2 system was developed using pairwise addition for the four-body energy term within the double many-body expansion. The topological features of the obtained function are compared with a previous one reported by Hippler et al. [J. Phys. Chem. 90, 6158 (1986)]. To test the accuracy of the PES, additional coupled cluster singles and doubles method with a perturbative contribution of connected triples calculations were carried out for the global minimum configuration. From dynamical calculations, the cross sections for the T-V excitation process indicate a barrier-type mechanism due to strong repulsive interactions between SO2 molecules and the Ar atom. Corrections to zero-point energy leakage in QCT were carried out using vibrational energy quantum mechanical threshold of the complex and variations. Rate coefficients and cross sections are calculated for some vibrational transitions using pseudo-quantization approaches of the vibrational energy of products. Main attributes of the title molecular collision are discussed and compared with available information in the literature.
Evolutionary dynamics in the public goods games with switching between punishment and exclusion
Authors: Liu Linjie , Wang Shengxian , Chen Xiaojie , Perc Matjaž
Published: October 2018

Pro-social punishment and exclusion are common means to elevate the level of cooperation among unrelated individuals. Indeed, it is worth pointing out that the combined use of these two strategies is quite common across human societies. However, it is still not known how a combined strategy where punishment and exclusion are switched can promote cooperation from the theoretical perspective. In this paper, we thus propose two different switching strategies, namely, peer switching that is based on peer punishment and peer exclusion, and pool switching that is based on pool punishment and pool exclusion. Individuals adopting the switching strategy will punish defectors when their numbers are below a threshold and exclude them otherwise. We study how the two switching strategies influence the evolutionary dynamics in the public goods game. We show that an intermediate value of the threshold leads to a stable coexistence of cooperators, defectors, and players adopting the switching strategy in a well-mixed population, and this regardless of whether the pool-based or the peer-based switching strategy is introduced. Moreover, we show that the pure exclusion strategy alone is able to evoke a limit cycle attractor in the evolutionary dynamics, such that cooperation can coexist with other strategies.
Permutation invariant polynomial neural network approach to fitting potential energy surfaces. IV. Coupled diabatic potential energy matrices
Authors: Xie Changjian , Zhu Xiaolei , Yarkony David R. , Guo Hua
Published: October 2018

A machine learning method is proposed for representing the elements of diabatic potential energy matrices (PEMs) with high fidelity. This is an extension of the so-called permutation invariant polynomial-neural network (PIP-NN) method for representing adiabatic potential energy surfaces. While for one-dimensional irreducible representations the diagonal elements of a diabatic PEM are invariant under exchange of identical nuclei in a molecular system, the off-diagonal elements require special symmetry consideration, particularly in the presence of a conical intersection. A multiplicative factor is introduced to take into consideration the particular symmetry properties while maintaining the PIP-NN framework. We demonstrate here that the extended PIP-NN approach is accurate in representing diabatic PEMs, as evidenced by small fitting errors and by the reproduction of absorption spectra and product branching ratios in both H2O(X̃/B̃) and NH3(X̃/Ã) non-adiabatic photodissociation.
Resonances for random highly oscillatory potentials
Authors: Drouot Alexis
Published: October 2018

We study discrete spectral quantities associated with Schrödinger operators of the form −ΔRd+VN, d odd. The potential VN models a highly disordered crystal; it varies randomly at scale N−1 ≪ 1. We use perturbation analysis to obtain almost sure convergence of the eigenvalues and scattering resonances of −ΔRd + VN as N → ∞. We identify a stochastic and a deterministic regime for the speed of convergence. The type of regime depends whether the low frequency effects due to large deviations overcome the (deterministic) constructive interference between highly oscillatory terms.
Redox-dependent niche differentiation provides evidence for multiple bacterial sources of glycerol tetraether lipids in lakes
Authors: Weber Yuki , Sinninghe Damsté Jaap S. , Zopfi Jakob , De Jonge Cindy , Gilli Adrian , Schubert Carsten J. , Lepori Fabio , Lehmann Moritz F. , Niemann Helge
Published: October 2018

Significance

Reliable prediction of future climate conditions requires a thorough understanding of climate variability throughout Earth’s history. Microbial molecular fossils, such as bacterial membrane-spanning tetraether lipids [branched glycerol dialkyl glycerol tetraethers (brGDGTs)], have proven to be particularly useful for the assessment of past climatic conditions, because they occur ubiquitously in the environment and show compositional changes related to temperature. However, the identity and ecology of brGDGT-producing bacteria is largely unknown, and a mechanistic basis for brGDGT-based paleoclimate reconstruction is still lacking. Here, we present insights into the ecological parameters that affect brGDGT synthesis in lakes, demonstrating that eutrophic lakes with oxygen-deprived bottom waters are the preferred sites for brGDGT-based reconstructions of continental climate.
Machine learning determination of atomic dynamics at grain boundaries
Authors: Sharp Tristan A. , Thomas Spencer L. , Cubuk Ekin D. , Schoenholz Samuel S. , Srolovitz David J. , Liu Andrea J.
Published: October 2018

Significance

A machine learning method is used to analyze the atomic structures that rearrange within the grain boundaries of polycrystals. The method readily separates the atomic structures into those that rarely rearrange and those that often rearrange. The likelihood of an atom rearranging under a thermal fluctuation is correlated with free volume and potential energy but is not entirely attributable to those quantities. A machine-learned quantity allows estimation of the energy barrier to rearrangement for particular atoms. The grain boundary atoms that rearrange most have more possible rearrangement trajectories rather than much-reduced energy barriers, as in bulk glasses. The work suggests that polycrystal plasticity can be studied in part from the local atomic structural environments without traditional classification of microstructure.
Protein shape modulates crowding effects
Authors: Guseman Alex J. , Perez Goncalves Gerardo M. , Speer Shannon L. , Young Gregory B. , Pielak Gary J.
Published: October 2018

Significance

Macromolecular crowding influences protein−protein interactions via hard-core repulsions and chemical interactions. Scaled particle theory predicts that the effect of hard-core repulsions depends on the shape of the protein complex, and simple ideas about chemical interactions predict a dominant role for the chemical qualities of the protein surface. The theory predicts that a collapsed, ellipsoidal, dimer will be stabilized by hard-core repulsions, whereas a less collapsed, side-by-side, dimer will not. We applied scaled particle theory to two dimers with nearly identical surfaces but different shapes. Our results support the predictions; crowders that interact primarily through hard-core repulsions stabilize the ellipsoidal domain-swapped dimer more than the side-by-side dimer, whereas crowders that interact via chemical interactions have the same effect on both dimers.
Molecular mechanism of activation of the immunoregulatory amidase NAAA
Authors: Gorelik Alexei , Gebai Ahmad , Illes Katalin , Piomelli Daniele , Nagar Bhushan
Published: October 2018

Significance

There is a strong need for new analgesic and antiinflammatory medicines that are both effective and safe. Animal studies have shown that inhibition of
N
-acylethanolamine acid amidase (NAAA)—an intracellular enzyme that degrades the lipid mediator palmitoylethanolamide—causes profound analgesic and antiinflammatory effects. To facilitate the discovery of drugs targeting this protein and to better understand its mechanism of action, we determined its 3D structure. Our results illustrate the sequential steps leading to the activation of NAAA at lipid membranes, and reveal how current inhibitors block this enzyme.
mTOR inhibitors lower an intrinsic barrier to virus infection mediated by IFITM3
Authors: Shi Guoli , Ozog Stosh , Torbett Bruce E. , Compton Alex A.
Published: October 2018

Significance

Gene delivery by virus-like particles holds enormous therapeutic potential to correct inherited genetic disorders and to prevent infectious disease. However, cells express antiviral factors that prevent virus infection and, consequently, limit the success of gene therapy. Here, we reveal the mechanism by which the drug rapamycin improves lentivirus-mediated gene delivery. Rapamycin treatment led to degradation of IFITM3, a broad and potent antiviral protein which inhibits virus entry into cells. IFITM3 is selectively cleared from endosomes, the sites where viral and cellular membranes fuse, and is sorted for disposal in lysosomes. While revealing an immunosuppressive function with clinical benefits, we caution that rapamycin use in humans may facilitate infection by pathogenic viruses like Influenza A virus.
Human leukemia mutations corrupt but do not abrogate GATA-2 function
Authors: Katsumura Koichi R. , Mehta Charu , Hewitt Kyle J. , Soukup Alexandra A. , Fraga de Andrade Isabela , Ranheim Erik A. , Johnson Kirby D. , Bresnick Emery H.
Published: October 2018

Significance

GATA-2 functions in stem and progenitor cells to control blood cell development, and its mutations cause blood diseases (immunodeficiency, myelodysplasia, and myeloid leukemia). How GATA-2 mutations cause these diseases is unclear. We innovated a genetic complementation assay to analyze functional ramifications of GATA-2 disease mutations. The activities of GATA-2 and mutants were quantified in blood progenitor cells from mice engineered to express a low level of GATA-2 due to deletion of an essential
Gata2
enhancer. Unexpectedly, the mutants were not only competent to induce myeloid cells, but their activities exceeded that of GATA-2. These results transform the current paradigm that disease mutations are solely inhibitory, and ectopically low GATA-2 levels/activity constitute the disease mechanism.
Affective constructions in Tsezic languages
Authors: Comrie Bernard , Forker Diana , Khalilova Zaira
Published: October 2018

This article addresses affective (“experiencer”) constructions in the Tsezic languages (Nakh-Daghestanian), which represent the most frequent type of non-canonical subject constructions in these languages. They differ from transitive constructions in a number of ways that go far beyond case marking and affect various domains of grammar (e.g. inflectional morphology, complex clause structures, reflexive and reciprocal binding, etc.). In this paper, we explore morphological, syntactic and semantic features of Tsezic affective constructions from a typological perspective. We investigate variation, stability, and change between the constructions in the various Tsezic languages and try to give explanations for the observed patterns of variation.
Dative case and oblique subjects
Authors: Van Valin Jr. Robert D.
Published: October 2018

Oblique subjects often occur in the dative case in many languages, and given that dative subjects frequently co-occur with experiential verbs, this has led to the view that dative signals ‘experiencer’, along with its ‘recipient’ meaning with verbs of giving. There are, however, many other uses of the dative which do not fall into either of these categories. This article argues that when one considers the full range of uses of the dative case across languages, it becomes clear that the dative is not associated with any particular grammatical function or with any particular meaning or thematic role. Because of the lack of any consistent grammatical function or meaning, it will be argued that dative is a default case, a kind of ‘elsewhere’ case, which is assigned when no other case rules can apply (Silverstein 1976, 1993). The appearance of a consistent semantics for some uses of the dative, e.g. marking experiencers, could be analyzed as the result of the blocking of the nominative rule to indicate deviation from the transitive prototype. An analysis of these phenomena in terms of Role and Reference Grammar is presented. Further evidence for the lack of an inherent meaning for the dative comes from alternations involving the case marking of causees in monoclausal causative constructions.
Making sense of grammatical variation in Norwegian
Authors: Sameien Marianne Brodahl , Spilling Eivor Finset , Enger Hans-Olav
Published: October 2018

This study examines two examples of grammatical variation in Norwegian inflection, strong versus weak verb conjugation and affixal versus periphrastic adjective comparison. The main claim is that the choice of variants is not as arbitrary as one may think, which rather indicates a division of labour. The strong verb inflection tends to be motivated not only by phonology, but also by semantics. The affixal and periphrastic adjective comparisons tend to be used with different sets of adjectives and for different semantic purposes. These observations support the Principle of Contrast, the idea that a difference in form normally relates to a difference in meaning.
The consequence of immersion time in chemical bath deposition on the properties of CuO thin films
Authors: Ramya V. , Neyvasagam K. , Chandramohan R. , Mohan R. , Valanarasu S. , Franklin Benial A. Milton
Published: October 2018

In this study, the effect of immersion time of the substrate in the chemical deposition bath on the physical properties of cupric oxide films is estimated by varying the immersion time as 15, 30, 45, 60 and 75 mins, respectively. The XRD studies revealed that the thin films showed a monoclinic structure with preferential orientation along (111) plane. Using X-ray profile analysis such as crystallite size, microstrain, dislocation density and stacking fault is estimated. Morphological studies revealed that the surface of films has uniformity and the particle size maximum for 45 min immersion time. In optical studies band gap, refractive index, extinction coefficient and optical conductivity have been estimated. The variations in immersion time had a considerable effect on the electrical parameters of films are confirmed. The studies revealed that the immersion time on CBD does have a significant role in deciding the property of the CuO thin films grown.
Targeting neuro–immune communication in neurodegeneration: Challenges and opportunities
Authors: Deczkowska Aleksandra , Schwartz Michal
Published: October 2018

Immune cells patrol the brain and can support its function, but can we modulate brain–immune communication to fight neurological diseases? Here, we briefly discuss the mechanisms orchestrating the cross-talk between the brain and the immune system and describe how targeting this interaction in a well-controlled manner could be developed as a universal therapeutic approach to treat neurodegeneration.
Kinetic properties of persistent Na+ current orchestrate oscillatory bursting in respiratory neurons
Authors: Yamanishi Tadashi , Koizumi Hidehiko , Navarro Marco A. , Milescu Lorin S. , Smith Jeffrey C.
Published: October 2018

The rhythmic pattern of breathing depends on the pre-Bötzinger complex (preBötC) in the brainstem, a vital circuit that contains a population of neurons with intrinsic oscillatory bursting behavior. Here, we investigate the specific kinetic properties that enable voltage-gated sodium channels to establish oscillatory bursting in preBötC inspiratory neurons, which exhibit an unusually large persistent Na+ current (INaP). We first characterize the kinetics of INaP in neonatal rat brainstem slices in vitro, using whole-cell patch-clamp and computational modeling, and then test the contribution of INaP to rhythmic bursting in live neurons, using the dynamic clamp technique. We provide evidence that subthreshold activation, persistence at suprathreshold potentials, slow inactivation, and slow recovery from inactivation are kinetic features of INaP that regulate all aspects of intrinsic rhythmic bursting in preBötC neurons. The slow and cumulative inactivation of INaP during the burst active phase controls burst duration and termination, while the slow recovery from inactivation controls the duration of the interburst interval. To demonstrate this mechanism, we develop a Markov state model of INaP that explains a comprehensive set of voltage clamp data. By adding or subtracting a computer-generated INaP from a live neuron via dynamic clamp, we are able to convert nonbursters into intrinsic bursters, and vice versa. As a control, we test a model with inactivation features removed. Adding noninactivating INaP into nonbursters results in a pattern of random transitions between sustained firing and quiescence. The relative amplitude of INaP is the key factor that separates intrinsic bursters from nonbursters and can change the fraction of intrinsic bursters in the preBötC. INaP could thus be an important target for regulating network rhythmogenic properties.
The change of value of soaked-CBR in embankment of subgrade due to water logging and repeated vehicles load
Authors: Nurtjahjaningtyas I , Mochtar I B , Mochtar N E
Published: October 2018

The value of soaked-CBR in subgrade soil is very important in the highway pavement thickness design [1]. If the soaked-CBR value of the subgrade does not meet the requirements, it is necessary to improve the soil by blasting with a better material. This is done to prevent damage to the road. Damage to the pavement surface may also cause damage to the subgrade. Alternatively, the damage to the pavement surface begins with damage on the subgrade. If the subgrade decreases in its power - caused by repetitive vehicle loads, otherwise known as repetition vehicle load, then it can collapse the foundation layer, in which - then continues on the surface damage. Based on the phenomenon, this research is conducted to know the change of soaked-CBR value on subgrade soil due to water logging and repetition of vehicle load passing. The result shows that the soaked-CBR value will increase along with the number of vehicles passing up to 25x passings, then down to 50x passings which is the lowest value of all load variations. After 50x passings, CBR value will increase slightly up to 250x passings which then decrease until the end of the research.
New Perspectives on Emotional Processing in People with Symptomatic Huntington’s Disease: Impaired Emotion Regulation and Recognition of Emotional Body Language†
Authors: Zarotti Nicolò , Fletcher Ian , Simpson Jane
Published: October 2018

Objective

Emotion regulation and emotional body language (EBL) recognition represent two fundamental components of emotional processing that have recently seen a considerable surge in research interest, in part due to the role they play in optimizing mental health. This appears to be particularly true for clinical conditions that can profoundly affect emotional functioning. Among these is Huntington’s disease (HD), a neurodegenerative disorder that is associated with several psychological difficulties and cognitive impairments, including well-established deficits in facial emotion recognition. However, although the theoretical case for impairments is strong, the current evidence in HD on other components such as emotion regulation and EBL recognition is sparse.

Method

In this study, it was hypothesized that emotion regulation and recognition of EBL are impaired in people with symptomatic HD, and that these impairments significantly and positively correlate with each other. A between-subjects design was adopted to compare 13 people with symptomatic HD with 12 non-affected controls matched for age and education.

Results

The results showed that emotion regulation and EBL recognition were significantly impaired in individuals with HD. Moreover, a significant positive correlation was observed between facial and EBL recognition impairments, whereas EBL performance was negatively related to the disease stage. However, emotion regulation and recognition performances were not significantly correlated.

Conclusions

This investigation represents the first evidence of a deficit of emotion regulation and EBL recognition in individuals with HD. The clinical implications of these findings are explored, and indications for future research are proposed.
Towards region-specific propagation of protein functions
Authors: Koo Da Chen Emily , Bonneau Richard
Published: October 2018

Motivation

Due to the nature of experimental annotation, most protein function prediction methods operate at the protein-level, where functions are assigned to full-length proteins based on overall similarities. However, most proteins function by interacting with other proteins or molecules, and many functional associations should be limited to specific regions rather than the entire protein length. Most domain-centric function prediction methods depend on accurate domain family assignments to infer relationships between domains and functions, with regions that are unassigned to a known domain-family left out of functional evaluation. Given the abundance of residue-level annotations currently available, we present a function prediction methodology that automatically infers function labels of specific protein regions using protein-level annotations and multiple types of region-specific features.

Results

We apply this method to local features obtained from InterPro, UniProtKB and amino acid sequences and show that this method improves both the accuracy and region-specificity of protein function transfer and prediction. We compare region-level predictive performance of our method against that of a whole-protein baseline method using proteins with structurally verified binding sites and also compare protein-level temporal holdout predictive performances to expand the variety and specificity of GO terms we could evaluate. Our results can also serve as a starting point to categorize GO terms into region-specific and whole-protein terms and select prediction methods for different classes of GO terms.

Availability and implementation

The code and features are freely available at: https://github.com/ek1203/rsfp.

Supplementary information

Supplementary data are available at Bioinformatics online.
Impact of Next-generation Sequencing Defined Human Immunodeficiency Virus Pretreatment Drug Resistance on Virological Outcomes in the ANRS 12249 Treatment-as-Prevention Trial
Authors: Derache Anne , Iwuji Collins C , Baisley Kathy , Danaviah Siva , Marcelin Anne-Geneviève , Calvez Vincent , de Oliveira Tulio , Dabis François , Porter Kholoud , Pillay Deenan
Published: October 2018

Background

Previous studies in human immunodeficiency virus (HIV)-positive individuals on thymidine analogue backbone antiretroviral therapy (ART) with either nevirapine or efavirenz have suggested poorer virological outcomes in the presence of pretreatment drug resistance (PDR). We assessed the impact of PDR on virological suppression (VS; <50 copies/mL) in individuals prescribed primarily tenofovir/emtricitabine/efavirenz in rural KwaZulu-Natal within a treatment-as-prevention trial.

Methods

Among 1557 HIV-positive individuals who reported no prior ART at study entry and provided plasma samples, 1328 individuals with entry viral load (VL) >1000 copies/mL had next-generation sequencing (NGS) of the HIV pol gene with MiSeq technology. Results were obtained for 1148 individuals, and the presence of PDR was assessed at 5% and 20% detection thresholds. Virological outcome was assessed using Cox regression in 837 of 920 ART initiators with at least 1 follow-up VL after ART initiation.

Results

PDR prevalence was 9.5% (109/1148) and 12.8% (147/1148) at 20% and 5% thresholds, respectively. After a median of 1.36 years (interquartile range, 0.91–2.13), mostly on fixed-dose combination tenofovir/emtricitabine/efavirenz, presence of both nonnucleoside reverse transcriptase inhibitor (NNRTI)/nucleoside reverse transcriptase inhibitor PDR vs no PDR was associated with longer time to VS (adjusted hazard ratio [aHR], 0.32; 95% confidence interval [CI], 0.12–0.86), while there was no difference between those with only NNRTI PDR vs no PDR (aHR, 1.05; 95% CI, 0.82–1.34) at the 5% threshold. Similar differences were observed for mutations detected at the 20% threshold, although without statistical significance.

Conclusions

NGS uncovered a high prevalence of PDR among participants enrolled in trial clinics in rural KwaZulu-Natal. Dual-class PDR to a mainly tenofovir/emtricitabine/efavirenz regimen was associated with poorer VS. However, there was no impact of NNRTI PDR alone.

Clinical Trials Tegistration

NCT01509508; South African National Clinical Trials Register: DOH-27-0512-3974.
Patients at low surgical risk as defined by the Society of Thoracic Surgeons Score undergoing isolated interventional or surgical aortic valve implantation: in-hospital data and 1-year results from the German Aortic Valve Registry (GARY)
Authors: Bekeredjian Raffi , Szabo Gabor , Balaban Ümniye , Bleiziffer Sabine , Bauer Timm , Ensminger Stephan , Frerker Christian , Herrmann Eva , Beyersdorf Friedhelm , Hamm Christian , Beckmann Andreas , Möllmann Helge , Karck Matthias , Katus Hugo A , Walther Thomas
Published: October 2018

Aims

Transcatheter aortic valve implantation (TAVI) has become the standard treatment for patients with severe aortic valve stenosis at high surgical risk and may be considered for patients with intermediate risk. During the last few years, an increasing number of patients with low surgical risk have been treated with TAVI. In this study, low-risk patients undergoing isolated TAVI or surgical aortic valve replacement (SAVR) were analysed using data from the German Aortic Valve Registry (GARY).

Methods and results

All patients with a Society of Thoracic Surgeons Score of <4% undergoing TAVI or SAVR in 2014 and 2015 were evaluated. A total of 20 549 low surgical risk patients remained for further analysis, comprising 14 487 surgical patients and 6062 TAVI patients. Since TAVI patients were significantly older and had significantly more co-morbidities, a weighted propensity score model was used to compare SAVR and TAVI patients for in-hospital, 30-day, and 1-year mortality. Transcatheter aortic valve implantation patients showed a significantly higher in-hospital and 30-day survival than SAVR patients (in hospital survival TAVI vs. SAVR: 98.5% vs. 97.3%; P = 0.003; 30-day survival TAVI vs. SAVR: 98.1% vs. 97.1%; P = 0.014). At 1 year, survival rates did not differ significantly (survival TAVI vs. SAVR: 90.0% vs. 91.2%; P = 0.158).

Conclusion

In this first GARY analysis of low-risk patients, weighted comparison showed similar 1-year survival for TAVI and SAVR and higher in-hospital survival for TAVI patients.