bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 2-Arylbenzothiazol-5-amines from N,N-Dialkyl-3-nitroanilines
Authors: Nguyen Tung T. , Phan Nam T. S. , Pham Hang T. , Ho Tuan H. , Do Duy Q. , Nguyen Kim L. H.
Published: September 2020

We report a simple method for coupling of N,N-dialkyl-3-nitroarenes, elemental sulfur, and activated sp3 C–H bonds in 2-methylazaarenes or arylacetic acids to afford derivatives of 2-arylbenzothiazol-5-amines. Only DABCO base was required, and many heterocycles such as imidazoles, oxazoles, quinolines, and thiophenes were compatible with the reaction conditions. Our approach offers a simple route to useful substituted thiazol-5-amines from commercially available nitroarenes.
The Role of Lymphatics in Cholestasis: A Comprehensive Review
Authors: O'Brien April , Gasheva Olga , Alpini Gianfranco , Zawieja David , Gashev Anatoliy , Glaser Shannon
Published: September 2020

Cholestatic liver disease affects millions of people worldwide and stems from a plethora of causes such as immune dysfunction, genetics, cancerous growths, and lifestyle choices. While not considered a classical lymphatic organ, the liver plays a vital role in the lymph system producing up to half of the body's lymph per day. The lymphatic system is critical to the health of an organism with its networks of vessels that provide drainage for lymphatic fluid and routes for surveilling immune cells. Cholestasis results in an increase of inflammatory cytokines, growth factors, and inflammatory infiltrate. Left unchecked, further disease progression will include collagen deposition which impedes both the hepatic and lymphatic ducts, eventually resulting in an increase in hepatic decompensation, increasing portal pressures, and accumulation of fluid within the abdominal cavity (ascites). Despite the documented interplay between these vital systems, little is known about the effect of liver disease on the lymph system and its biological response. This review looks at the current cholestatic literature from the perspective of the lymphatic system and summarizes what is known about the role of the lymph system in liver pathogenesis during hepatic injury and remodeling, immune-modulating events, or variations in interstitial pressures.
Paroxysmal Sympathetic Hyperactivity
Authors: Scott Rachael A. , Rabinstein Alejandro A.
Published: September 2020

Paroxysmal sympathetic hyperactivity (PSH) is a relatively common, but often unrecognized, complication of acute diffuse or multifocal brain diseases, most frequently encountered in young comatose patients with severe traumatic brain injury. It is presumed to be caused by loss of cortical inhibitory modulation of diencephalic and brain stem centers and possible additional maladaptive changes in the spinal cord that combine to produce exaggerated sympathetic responses to stimulation. The syndrome consists of repeated sudden episodes of tachycardia, tachypnea, hypertension, sweating, and sometimes fever and dystonic posturing. The diagnosis is clinical. Treatment includes reducing any external stimulation that can trigger the episodes, and starting abortive (e.g., intravenous morphine) and preventive medications (e.g., gabapentin, propranolol, clonidine). Prompt and adequate treatment of PSH may reduce the likelihood of secondary complications, such as dehydration, weight loss and malnutrition, and muscle contractures.
Clinical Trials for Neurogenic Orthostatic Hypotension: A Comprehensive Review of Endpoints, Pitfalls, and Challenges
Authors: Palma Jose-Alberto , Kaufmann Horacio
Published: September 2020

Neurogenic orthostatic hypotension (nOH) is among the most debilitating nonmotor features of patients with Parkinson's disease (PD) and other synucleinopathies. Patients with PD and nOH generate more hospitalizations, make more emergency room visits, create more telephone calls/mails to doctors, and have earlier mortality than those with PD but without nOH. Overall, the health-related cost in patients with PD and OH is 2.5-fold higher compared with patients with PD without OH. Hence, developing effective therapies for nOH should be a research priority. In the last few decades, improved understanding of the pathophysiology of nOH has led to the identification of therapeutic targets and the development and approval of two drugs, midodrine and droxidopa. More effective and safer therapies, however, are still needed, particularly agents that could selectively increase blood pressure only in the standing position because supine hypertension is the main limitation of available drugs. Here we review the design and conduct of nOH clinical trials in patients with PD and other synucleinopathies, summarize the results of the most recently completed and ongoing trials, and discuss challenges, bottlenecks, and potential remedies.
Nonfreezing Cold Injury in a Pediatric Hiker
Authors: McCarthy Matthew T. , Savino Anthony K.
Published: September 2020

Nonfreezing cold injury has been primarily described in military populations as a result of prolonged exposure to wet environments and cold, but not freezing, temperatures. This type of injury occurs less commonly in the civilian population and in children, but poses a risk for short-term debilitating extremity pain, tissue damage, and infection and for long-term chronic neuropathic pain and temperature intolerance. We describe a case of nonfreezing cold injury in a pediatric hiker.
How Does Robotic-Arm Assisted Technology Influence Total Knee Arthroplasty Implant Placement for Surgeons in Fellowship Training?
Authors: Scholl Laura Y. , Hampp Emily L. , de Souza Kevin M. , Chang Ta-Cheng , Deren Matthew , Yenna Zachary C. , Sodhi Nipun , Mont Michael A , Westrich Geoffrey H.
Published: September 2020

Implant malalignment during total knee arthroplasty (TKA) may lead to suboptimal postoperative outcomes. Accuracy studies are typically performed with experienced surgeons; however, it is important to study less experienced surgeons when considering teaching hospitals where younger surgeons operate. Therefore, this study assessed whether robotic-arm assisted TKA (RATKA) allowed for more accurate and precise implant position to plan when compared with manual techniques when the surgery is performed by in-training orthopaedic surgical fellows. Two surgeons, currently in their fellowship training and having minimal RATKA experience, performed a total of six manual TKA (MTKA) and six RATKAs on paired cadaver knees. Computed tomography scans were obtained for each knee pre- and postoperatively. These scans were analyzed using a custom autosegmentation and autoregistration process to compare postoperative implant position with the preoperative planned position. Mean system errors and standard deviations were compared between RATKA and MTKA for the femoral component for sagittal, coronal, and axial planes and for the tibial component in the sagittal and coronal planes. A 2-Variance testing was performed using an α = 0.05. Although not statistically significant, RATKA was found to have greater accuracy and precision to plan than MTKA for: femoral axial plane (1.1° ± 1.1° vs. 1.6° ± 1.3°), coronal plane (0.9° ± 0.7° vs. 2.2° ± 1.0°), femoral sagittal plane (1.5° ± 1.3° vs. 3.1° ± 2.1°), tibial coronal plane (0.9° ± 0.5° vs. 1.9° ± 1.3°), and tibial sagittal plane (1.7° ± 2.6° vs. 4.7° ± 4.1°). There were no statistical differences between surgical groups or between the two surgeons performing the cases. With limited RATKA experience, fellows showed increased accuracy and precision to plan for femoral and tibial implant positions. Furthermore, these results were comparable to what has been reported for an experienced surgeon performing RATKA.
The small-deflection energy analyzer (SDEA): Enabling multi-point investigations in the thermosphere–ionosphere
Authors: Herrero Federico , Nicholas Andrew , Finne Ted , Jones Hollis , Aalami Dean
Published: September 2020

The Small-Deflection Energy Analyzer (SDEA), a new type of parallel plate analyzer of high sensitivity and resolution, enables CubeSat applications for new ionosphere–thermosphere investigations. SDEA’s data of angle-energy distributions yield the thermosphere–ionosphere parameters of neutral wind and ion-drift vectors with corresponding temperatures and densities. Less than 4 cm in total length and 2 cm on the side, SDEA is used in the wind-temperature and ion-drift temperature spectrometers pair to provide two of the three instrument functions in the Wind-Ion-Neutral-Composition Suite now operating in three satellites in a low-Earth orbit. The small-deflection feature of SDEA allows miniaturization with several advantages discussed within. A description of SDEA is followed by examples of laboratory and a limited amount of flight data taken in low-Earth-orbit to demonstrate precision possible with SDEA. Strengths and weaknesses are discussed.
Optical and mechanical design of a telescope for lunar spectral irradiance measurements from a high-altitude aircraft
Authors: Zarobila C. J. , Grantham S. , Brown S. W. , Woodward J. T. , Maxwell S. E. , Defibaugh D. R. , Larason T. C. , Turpie K. R.
Published: September 2020

We have designed a non-imaging telescope for measurement of the spectral irradiance of the moon. The telescope was designed to be integrated into a wing pod of a National Aeronautics and Space Administration ER-2 research aircraft to measure lunar spectral irradiance during flight. The telescope and support system were successfully flown in August 2018 at altitudes near 21 km and at speeds of ∼760 km/h. The wing pod in which the telescope is mounted has an opening through which the moon can be observed. The mount exposes the telescope to high winds, low pressures, temperatures near −60 °C, and vibrations both due to flight and due to the motion of the aircraft on the ground. This required a telescope design with high thermal stability and high resistance to shock. The optical design of the telescope is optimized to have high throughput and spatially uniform transmission from 380 nm to 1000 nm over a field of view about three times the angular size of the moon as viewed from the Earth. The final design resulted in a telescope with singlet design incorporating a 139.7 mm lens with an effective focal length of 377 mm and a field of view of 1.6°. The light from the telescope is introduced into an integrating sphere, which destroys the image and the polarization for measurement by a fiber-coupled spectroradiometer. Herein, we present an overview of the instrument and support system with emphasis on the telescope design.
Monitoring the build-up of hydrogen polarization for polarized hydrogen–deuteride (HD) targets with nuclear magnetic resonance (NMR) at 17 T
Authors: Ohta T. , Fujiwara M. , Hotta T. , Ide I. , Ishizaki K. , Kohri H. , Yanai Y. , Yosoi M.
Published: September 2020

We report on the frozen-spin polarized hydrogen–deuteride (HD) targets for photoproduction experiments at SPring-8/LEPS. Pure HD gas with a small amount of ortho-H2 (∼0.1%) and a very small amount of para-D2 (∼0.001%) was liquefied and solidified by liquid helium. The temperature of the produced solid HD was reduced to about 30 mK with a dilution refrigerator. A magnetic field (17 T) was applied to the HD to grow the polarization with the static method. After the aging of the HD at low temperatures in the presence of a high-magnetic field strength for three months, the polarization froze. Almost all ortho-H2 molecules were converted to para-H2 molecules. Most remaining para-D2 molecules were converted to ortho-D2 molecules. The para-H2 and ortho-D2 molecules exhibited weak spin interactions with the HD. If the concentrations of the ortho-H2 and para-D2 were reduced appropriately at the beginning of the aging process, the aging time can be shortened. We have developed a new nuclear magnetic resonance (NMR) system to measure the relaxation times (T1) of the 1H and 2H nuclei with two frequency sweeps at the respective frequencies of 726 MHz and 111 MHz and succeeded in the monitoring of the polarization build-up at decreasing temperatures from 600 mK to 30 mK at 17 T. Automatic NMR measurements with the frequency sweeps enabled us to omit the use of a manual tuning circuit and to remove magnetic field sweeps with eddy current heat. This technique enables us to optimize the concentration of the ortho-H2 and to efficiently polarize the HD target within a shortened aging time.
Wideband (8–18 GHz) microwave absorption dominated electromagnetic interference (EMI) shielding composite using copper aluminum ferrite and reduced graphene oxide in polymer matrix
Authors: Acharya Sanghamitra , Datar Suwarna
Published: September 2020

The development of an efficient radar absorbing material (RAM) is a need of the day due to rapid growth in satellite, electronic, and telecommunication industries (especially, in the GHz frequency region). Herein, an easy fabrication technique is presented to design a lightweight and flexible absorption dominated electromagnetic interference shielding material by dispersion of magnetic nanoparticles of a CuAl2Fe10O19 (CFA) decorated reduced graphene oxide (RGO) filler into the polyvinylidene fluoride (PVDF) matrix. This has been done by a simple chemical reduction method in the presence of hydrazine. It was observed that the synergetic effect of all filler contents along with multiple relaxation mechanisms due to the interface of RGO, CFA, and PVDF leads to strong absorption rather than reflection. This makes the composite an excellent candidate for RAM in the X band as well as in the Ku band. To develop a material for absorption in wideband frequencies is challenging, especially if the intended absorption is above 60 dB. In the present work, shielding efficiency (SE) of ∼60 dB in the X band and ∼50 dB in the Ku band has been achieved with more than 90% SE due to absorption. The effect of an individual filler content in wave attenuation has been analyzed from the point of view of absorption coefficient, complex permittivity and permeability, and attenuation constant.
Exploring Hilbert space on a budget: Novel benchmark set and performance metric for testing electronic structure methods in the regime of strong correlation
Authors: Stair Nicholas H. , Evangelista Francesco A.
Published: September 2020

This work explores the ability of classical electronic structure methods to efficiently represent (compress) the information content of full configuration interaction (FCI) wave functions. We introduce a benchmark set of four hydrogen model systems of different dimensionalities and distinctive electronic structures: a 1D chain, a 1D ring, a 2D triangular lattice, and a 3D close-packed pyramid. To assess the ability of a computational method to produce accurate and compact wave functions, we introduce the accuracy volume, a metric that measures the number of variational parameters necessary to achieve a target energy error. Using this metric and the hydrogen models, we examine the performance of three classical deterministic methods: (i) selected configuration interaction (sCI) realized both via an a posteriori (ap-sCI) and variational selection of the most important determinants, (ii) an a posteriori singular value decomposition (SVD) of the FCI tensor (SVD-FCI), and (iii) the matrix product state representation obtained via the density matrix renormalization group (DMRG). We find that the DMRG generally gives the most efficient wave function representation for all systems, particularly in the 1D chain with a localized basis. For the 2D and 3D systems, all methods (except DMRG) perform best with a delocalized basis, and the efficiency of sCI and SVD-FCI is closer to that of DMRG. For larger analogs of the models, the DMRG consistently requires the fewest parameters but still scales exponentially in 2D and 3D systems, and the performance of SVD-FCI is essentially equivalent to that of ap-sCI.
Coupled very-high permittivity dielectric resonators for clinical MRI
Authors: Ivanov Viacheslav , Shchelokova Alena , Andreychenko Anna , Slobozhanyuk Alexey
Published: September 2020

Dielectric resonators made of high permittivity materials with low losses have been extensively studied for application in magnetic resonance imaging (MRI) and magnetic resonance spectroscopy. They can focus, redistribute, and enhance the radio frequency magnetic field in a controlled way. In this Letter, we investigate coupled very-high permittivity dielectric resonators for clinical bilateral breast MRI. The resonators are tuned to support a TE mode within the frequency of 3 T MRI and implemented as a pair of coaxial hollow cylinders consisting of ceramic rings with extremely high permittivity (ε ∼ 870) and low loss. We study the electromagnetic coupling between two resonators placed in the near field and analyze the impact of symmetric and antisymmetric mode excitation on the sensitivity of the MRI machine. We experimentally verify that the coupling of the mode with symmetric field distribution to the radio frequency body birdcage coil allows us to enhance the receive sensitivity substantially and to decrease the excitation power needed to provide the optimal transmit efficiency, thus making the MRI procedure safer. Our work offers a practical method to realize a simple yet very effective system based on dielectric resonators for bilateral breast imaging.
Ion transport in small-molecule and polymer electrolytes
Authors: Son Chang Yun , Wang Zhen-Gang
Published: September 2020

Solid-state polymer electrolytes and high-concentration liquid electrolytes, such as water-in-salt electrolytes and ionic liquids, are emerging materials to replace the flammable organic electrolytes widely used in industrial lithium-ion batteries. Extensive efforts have been made to understand the ion transport mechanisms and optimize the ion transport properties. This perspective reviews the current understanding of the ion transport and polymer dynamics in liquid and polymer electrolytes, comparing the similarities and differences in the two types of electrolytes. Combining recent experimental and theoretical findings, we attempt to connect and explain ion transport mechanisms in different types of small-molecule and polymer electrolytes from a theoretical perspective, linking the macroscopic transport coefficients to the microscopic, molecular properties such as the solvation environment of the ions, salt concentration, solvent/polymer molecular weight, ion pairing, and correlated ion motion. We emphasize universal features in the ion transport and polymer dynamics by highlighting the relevant time and length scales. Several outstanding questions and anticipated developments for electrolyte design are discussed, including the negative transference number, control of ion transport through precision synthesis, and development of predictive multiscale modeling approaches.
Solvation and transport of lithium ions in deep eutectic solvents
Authors: Srinivasan H. , Sharma V. K. , Mukhopadhyay R. , Mitra S.
Published: September 2020

Lithium based deep eutectic solvents (DESs) are excellent candidates as eco-friendly electrolytes for lithium ion batteries. While some of these DESs have shown promising results, a clear mechanism of lithium ion transport in DESs is not yet established. This work reports the study on the solvation and transport of lithium in a DES made from lithium perchlorate and acetamide using Molecular Dynamics (MD) simulation and inelastic neutron scattering. Based on hydrogen bonding (H-bonding) of acetamide with neighboring molecules/ions, two states are largely prevalent: (1) acetamide molecules that are H-bonded to lithium ions (∼36%) and (2) acetamide molecules that are entirely free (∼58%). Analyzing their stochastic dynamics independently, it is observed that the long-range diffusion of the former is significantly slower than that of the latter. This is also validated from the neutron scattering experiment on the same DES system. Furthermore, the analysis of the lithium dynamics shows that the diffusion of acetamide molecules in the first category is strongly coupled to that of lithium ions. On an average, the lithium ions are H-bonded to ∼3.2 acetamide molecules in their first solvation. These observations are further bolstered through the analysis of the H-bond correlation function between acetamide and lithium ions, which shows that ∼90% of lithium ionic transport is achieved by vehicular motion where the ions diffuse along with their first solvation shell. It is also observed that the ionic motions are largely uncorrelated and the conductivity of lithium ions in the DES is found to be 11 mS/cm. The findings of this work are an important advancement in understanding solvation and transport of lithium in the DES.
Theoretical study of the chemical reaction mechanism and rate of SFn− + H2O (n = 3–6) under discharge
Authors: Xu Mengyuan , Yan Jing , Yang Minghao , Geng Yingsan , Liu Zhiyuan , Wang Jianhua
Published: September 2020

Both the chemical reaction mechanism and rate can largely explain the formation mechanism of the by-products of SF6. By understanding this mechanism, we can develop and improve models of the chemical kinetics of SF6 decomposition under discharge. Using quantum chemistry, this study compares the reaction mechanisms and rates of SF6−, SF5−, SF4−, and SF3− and H2O under discharge at 298 K–12 000 K and reveals the formation mechanism of their anionic by-products, i.e., SOF4−, SOF3−, SOF2−, and SOF−. The key parameters such as the reaction equation and reaction rate to improve the chemical kinetic models under partial and arc discharges were then obtained. In this study, the structural optimizations, vibrational frequencies, and zero-point energies of the reactants, products, complexes, intermediates, and transition states were calculated at the B3LYP/6-311G(d,p) level. The single-point energies of all species were calculated at the CCSD(T)/aug-cc-PVTZ level. The strengths and sites of weak interactions were determined from the electrostatic potential of the molecular surface, and the reaction rates were obtained using transition state theory. It has been found that SF6−, SF5−, SF4−, and SF3− combined with H2O to form weak-interaction complexes dominated by hydrogen bonding, thus providing the initial conditions for R1, R2, R3, and R4, respectively. All four reactions were composed of multiple elementary reactions with the first step being the rate-determining step. Moreover, compared to their corresponding reactions of SF5, SF4, SF3, and SF2 with H2O, they achieved lower potential energy barriers and higher reaction rates. Note that the reaction rates decreased in the following order: R3 > R2 > R1 > R4.
Scattering theory in homogeneous Sobolev spaces for Schrödinger and wave equations with rough potentials
Authors: Mizutani Haruya
Published: September 2020

We study the scattering theory for the Schrödinger and wave equations with rough potentials in a scale of homogeneous Sobolev spaces. The first half of this paper is concerned with an inverse-square potential in both of subcritical and critical constant cases, which is a particular model of scaling-critical singular perturbations. In the subcritical case, the existence of the wave and inverse wave operators defined on a range of homogeneous Sobolev spaces is obtained. In particular, we have the scattering to a free solution in the homogeneous energy space for both of the Schrödinger and wave equations. In the critical case, it is shown that the solution is asymptotically a sum of an n-dimensional free wave and a rescaled two-dimensional free wave. The second half of this paper is concerned with a generalization to a class of strongly singular decaying potentials. We provide a simple criterion in an abstract framework to deduce the existence of wave operators defined on a homogeneous Sobolev space from the existence of the standard ones defined on a base Hilbert space.
Polarization control of epitaxial barium titanate (BaTiO3) grown by pulsed-laser deposition on a MBE-SrTiO3/Si(001) pseudo-substrate
Authors: Wang Tsang-Hsuan , Hsu Po-Chun (Brent) , Korytov Maxim , Genoe Jan , Merckling Clement
Published: September 2020

Barium titanate (BaTiO3 or BTO) is a perovskite structure material with interesting intrinsic properties, such as spontaneous ferroelectricity or electro-optical behavior, which strongly depend on thin film crystallinity. For such functional oxide systems, the pulsed-laser deposition (PLD) approach is one promising growth technique due to its precise stoichiometry control of the metals composing the perovskite crystal and higher oxygen environment compared to the classically used molecular beam epitaxy (MBE) approach. In this article, we demonstrate a BTO epitaxial layer by PLD onto an Si(001) substrate thanks to a thin pseudomorphic SrTiO3 buffer layer grown by MBE. In our study, the various investigated PLD parameters show strong impacts on the BTO polarization orientation. Hence, adjusting the growth conditions allows control of the polarization orientation, which is crucial for both electronic and optical applications. In addition, lattice parameter changes of BTO layers are investigated using x-ray diffraction and cross-sectional transmission electron microscopy, which evidenced a correlation between mismatch relaxation and oxygen growth pressure. Finally, with the analysis of BTO C–V curves, the polarization direction transition is demonstrated electrically.
Switchable smart windows using a biopolymer network of cellulose nanocrystals imposed on a nematic liquid crystal
Authors: Satapathy Pragnya , Parthasarathi Srividhya , Rao D. S. Shankar , Bano Saleheen , Negi Yuvraj Singh , Prasad S. Krishna
Published: September 2020

A polymer stabilized liquid crystal (PSLC) system formed by a nematic contained in a biopolymer network of cellulose nanocrystals, exhibiting many attractive features, is demonstrated. The threshold or the minimum voltage needed to operate the electro-optic device does not depend on the concentration of the polymer, a feature that is in contrast to the standard PSLC systems. A second point, more important from the driving circuit point of view, is that the voltage-off response time drastically reduces and even becomes practically invariant over the thermal range of the nematic phase. A smart window fabricated using this biopolymer network system exhibits good contrast between the scattering and transparent states driven by voltage and shows an exceptionally high haze factor. A highlight of the device fabrication is that the employed protocol is facile, making it appealing for a potentially viable smart window application.
Point defects in two-dimensional hexagonal boron nitride: A perspective
Authors: Zhang Jijun , Sun Rong , Ruan Dongliang , Zhang Min , Li Yanxi , Zhang Kai , Cheng Faliang , Wang Zhongchang , Wang Zhi-Ming
Published: September 2020

Two-dimensional (2D) hexagonal boron nitride (h-BN) is one of the most promising materials for many technological applications ranging from optics to electronics. In past years, a property-tunable strategy that involves the construction of electronic structures of h-BN through an atomic-level design of point defects has been in vogue. The point defects imported during material synthesis or functionalization by defect engineering can endow h-BN with new physical characteristics and applications. In this Perspective, we survey the current state of the art in multifunction variations induced by point defects for 2D h-BN. We begin with an introduction of the band structure and electronic property of the pristine h-BN. Subsequently, the formation and characterization of the most obvious point defects and their modulation in electronic structures of h-BN nanomaterials are envisaged in theory. The experimental results obtained by atom-resolved transmission electron microscopy, magnetic measurement, and optical measurements have provided insights into the point defect engineered structures and their corresponding emerging properties. Finally, we highlight the perspectives of h-BN nanomaterials for heterostructures and devices. This Perspective provides a landscape of the point defect physics involved to demonstrate the modulation of the structure and functionalities in h-BN and identify the roadmap for heterostructure and device applications, which will make advances in electronics, spintronics, and nanophotonics.
Thermoelastic properties of tungsten at simultaneous high pressure and temperature
Authors: Qi Xintong , Cai Nao , Wang Siheng , Li Baosheng
Published: September 2020

The compressional (P) and shear wave velocities (S) and unit cell volumes (densities) of polycrystalline tungsten (W) have been measured simultaneously up to 10.5 GPa and 1073 K using ultrasonic interferometry in conjunction with x-ray diffraction and x-radiography techniques. Thermoelastic properties of W were derived using different methods. We obtained the isothermal bulk modulus KT0 = 310.3(1.5) GPa, its pressure derivative K′T0 = 4.4(3), its temperature derivative at constant pressure (∂KT/∂T)P=−0.0138(1)GPaK−1 and at constant volume (∂KT/∂T)V=−0.0050GPaK−1, the thermal expansion α(0, T) = 1.02(27) × 10−5 + 7.39(3.2) × 10−9 T (K−1), as well as the pressure derivative of thermal expansion (∂α/∂P)T=−1.44(1)×10−7K−1GPa−1 based on the high-temperature Birch–Murnaghan equation of state (EOS), the Vinet EOS, and thermal pressure approach. Finite strain analysis allowed us to derive the elastic properties and their pressure/temperature derivatives independent of the choice of pressure scale. A least-squares fitting yielded KS0 = 314.5(2.5) GPa, KS0′ = 4.45(9), (∂KS/∂T)P = − 0.0076(6) GPa K−1, G0 = 162.4(9) GPa, G0′ = 1.8(1), (∂G/∂T)P = − 0.0175(9) GPa K−1, and α298K=1.23×10−5K−1. Fitting current data to the Mie–Grüneisen–Debye EOS with derived θ0=383.4K yielded γ0=1.81(6)andq=0.3. The thermoelastic parameters obtained from various approaches are consistent with one another and comparable with previous results within uncertainties. Our current study provides a complete and self-consistent dataset for the thermoelastic properties of tungsten at high P–T conditions, which is important to improve the theoretical modeling of these materials under dynamic conditions.
On the solution of the mean-spherical approximation (MSA) for ions in a dipolar solvent in the general case
Authors: Simonin Jean-Pierre
Published: September 2020

This paper deals with the problem of a mixture of hard spherical ions and central point dipoles, described within the mean-spherical approximation. In this non-primitive model, the species have different diameters (unrestricted case). The first purpose of this work is to establish clear and valid equations for this problem and present a method to solve them. Formulas for the pressure, the internal and Helmholtz energies, and the chemical potentials of the species are given and discussed. The results are illustrated by considering a binary 1–1 electrolyte solution in a water-like dipolar solvent.
A bilateral tumor model identifies transcriptional programs associated with patient response to immune checkpoint blockade
Authors: Chen Ivy X. , Newcomer Kathleen , Pauken Kristen E. , Juneja Vikram R. , Naxerova Kamila , Wu Michelle W. , Pinter Matthias , Sen Debattama R. , Singer Meromit , Sharpe Arlene H. , Jain Rakesh K.
Published: September 2020

Significance

Immune checkpoint blockade (ICB) has revolutionized treatment of many cancer types, but the majority of treated patients still do not respond to ICB. There is an urgent need to identify predictive biomarkers of response prior to or shortly after therapy initiation, as well as the underlying mechanisms. Here we utilize a model of bilateral tumor implantations followed by resection and immunotherapy-response assessment to study the tumor microenvironment shortly following treatment, identifying biomarkers for response or resistance at early time points. Our biomarker gene signatures derived from CD8+T cells significantly segregate patients by survival and associate with patient response to ICB. Our findings provide a general approach for studying mechanisms of resistance to ICB and discovering predictive biomarkers of response.
A conserved subcomplex within the bacterial cytokinetic ring activates cell wall synthesis by the FtsW-FtsI synthase
Authors: Marmont Lindsey S. , Bernhardt Thomas G.
Published: September 2020

Significance

Cell division is an essential process in bacteria and an attractive target for antibiotic development. A major activity of the division apparatus is the synthesis of the cell wall peptidoglycan that will ultimately fortify the poles of the daughter cells. How cell wall synthesis by the division machinery is regulated has remained unclear. In this report, we use a combination of genetics and biochemical reconstitution to demonstrate that a complex of the highly conserved FtsQ, FtsL, and FtsB proteins serves as an essential activator of cell wall synthesis within the cytokinetic ring.
Circulation of gut-preactivated naïve CD8+T cells enhances antitumor immunity in B cell-defective mice
Authors: Akrami Maryam , Menzies Rosemary , Chamoto Kenji , Miyajima Michio , Suzuki Ryuji , Sato Hiroyuki , Nishii Akiko , Tomura Michio , Fagarasan Sidonia , Honjo Tasuku
Published: September 2020

Significance

Accumulating evidence supports important roles for the microbiota in health and disease. The absence of IgA induces microbial dysbiosis, leading to inflammation in the gut environment. Here, we found that the strong antitumor immunity of B cell-deficient mice is due to their microbial dysbiosis, leading to activation of type I interferon (IFN) signaling in peripheral CD8+T cells. The constant circulation of CD8+T cells, particularly the naïve subset between the periphery and the gut, leads to the induction of a gut-educated naïve subpopulation in the periphery. Exposure to type I IFN in the gut endows this naïve subpopulation with superior effector potential. These data provide important insights into how the gut environment can shape peripheral immunity.
Keeping track of time: The fundamentals of cellular clocks
Authors: Gliech Colin R. , Holland Andrew J.
Published: September 2020

Biological timekeeping enables the coordination and execution of complex cellular processes such as developmental programs, day/night organismal changes, intercellular signaling, and proliferative safeguards. While these systems are often considered separately owing to a wide variety of mechanisms, time frames, and outputs, all clocks are built by calibrating or delaying the rate of biochemical reactions and processes. In this review, we explore the common themes and core design principles of cellular clocks, giving special consideration to the challenges associated with building timers from biochemical components. We also outline how evolution has coopted time to increase the reliability of a diverse range of biological systems.
Engineered high-affinity zinc binding site reveals gating configurations of a human proton channel
Authors: Cherny Vladimir V. , Musset Boris , Morgan Deri , Thomas Sarah , Smith Susan M.E. , DeCoursey Thomas E.
Published: September 2020

The voltage-gated proton channel (HV1) is a voltage sensor that also conducts protons. The singular ability of protons to penetrate proteins complicates distinguishing closed and open channels. When we replaced valine with histidine at position 116 in the external vestibule of hHV1, current was potently inhibited by externally applied Zn2+ in a construct lacking the two His that bind Zn2+ in WT channels. High-affinity binding with profound effects at 10 nM Zn2+ at pHo 7 suggests additional groups contribute. We hypothesized that Asp185, which faces position 116 in our closed-state model, contributes to Zn2+ chelation. Confirming this prediction, V116H/D185N abolished Zn2+ binding. Studied in a C-terminal truncated monomeric construct, V116H channels activated rapidly. Anomalously, Zn2+ slowed activation, producing a time constant independent of both voltage and Zn2+ concentration. We hypothesized that slow turn-on of H+ current in the presence of Zn2+ reflects the rate of Zn2+ unbinding from the channel, analogous to drug-receptor dissociation reactions. This behavior in turn suggests that the affinity for Zn2+ is greater in the closed state of hHV1. Supporting this hypothesis, pulse pairs revealed a rapid component of activation whose amplitude decreased after longer intervals at negative voltages as closed channels bound Zn2+. The lower affinity of Zn2+ in open channels is consistent with the idea that structural rearrangements within the transmembrane region bring Arg205 near position 116, electrostatically expelling Zn2+. This phenomenon provides direct evidence that Asp185 opposes position 116 in closed channels and that Arg205 moves between them when the channel opens.
Quantum state preparation of hydrogen atoms by hyperfine quenching
Authors: Alencar Amanda , Prazeres I , de Carvalho C R , Impens François , Medina A , de Castro Faria N V , Robert J , Jalbert Ginette
Published: September 2020

We discuss the use of a region of uniform and constant magnetic field in order to implement a two-state atomic polarizer for an H(2S) beam. We have observed that a device with such field configuration is capable of achieving an efficient polarization for a wide range of magnetic field intensities and atomic velocities. In addition, we establish a criterion that must be met to confirm a successful polarization. That is possible due to a specific beating pattern for the Lyman-α radiation expected for the outgoing two-state atomic beam.
Impact of chamber pressure and Si-doping on the surface morphology and electrical properties of homoepitaxial (100) β-Ga2O3thin films grown by MOVPE
Authors: Bin Anooz S , Grüneberg R , Chou T-S , Fiedler A , Irmscher K , Wouters C , Schewski R , Albrecht M , Galazka Z , Miller W , Schwarzkopf J , Popp A
Published: September 2020

The influence of chamber pressure and Si-doping on the growth rate, surface morphology and Hall mobility was investigated forβ-Ga2O3thin films homoepitaxially grown by metalorganic vapor phase epitaxy on Mg-dopedβ-Ga2O3(100) substrates with 4° miscut. Transitions from step-bunching to step-flow to 2D island growth modes were achieved by varying the chamber pressure from 10 mbar to 40 mbar and/or by varying the O2/Ga ratio. High-qualityβ-Ga2O3homoepitaxial thin films with a high electron mobility of 153 cm2Vs−1have been obtained at a chamber pressure of 25 mbar and a growth rate of 3.6 nm min−1. The Si-doped films show electron concentrations in the range of 1 × 1017to 2 × 1019cm−3. When increasing the chamber pressure to 40 mbar step-flow growth mode and high charge carrier mobility can only be preserved by adjusting the O2/Ga ratio and increasing the Ar push gas flow. Secondary ion mass spectrometry and Hall measurements for Si and electron concentration, respectively, revealed Si compensation at higher tetraethyl orthosilicate flux.
Nonadiabatic quasiparticle description of rotation-particle coupling in triaxial odd–odd nuclei
Authors: Siwach Pooja , Arumugam P , Modi S , Ferreira L S , Maglione E
Published: September 2020

A large wealth of data and a variety of models led to significant progress in understanding the spectra of deformed nuclei. However, a robust theoretical approach, which is less reliant on adjustable parameters is still elusive. Due to the scarcity of data, this drawback gets more pronounced while studying the exotic nuclei. With the motive to overcome this difficulty, we have developed the nonadiabatic quasiparticle approach for the description of rotational states in triaxial deformed odd–odd nuclei. The rotation-particle coupling is carried out utilizing an appropriate basis transformation such that the matrix elements of the odd–odd system can be written in terms of the rotor energies. This provides the advantage of studying the role of core more efficiently as compared to the conventional particle rotor model. The residual interaction between the valence proton and neutron is incorporated in two reliable ways, namely, the constant potential form and the zero-range interaction.
An equation of state for expanded metals
Authors: Schirmacher W , Pilgrim W-C , Hensel F
Published: September 2020

We present a model equation of states for expanded metals, which contains a pressure term due to a screened-Coulomb potential with a screening parameter reflecting the Mott–Anderson metal-to-nonmetal transition. As anticipated almost 80 years ago by Zel’dovich and Landau, this term gives rise to a second coexistence line in the phase diagram, indicating a phase separation between a metallic and a nonmetallic liquid.
A new dose quantity for evaluation and optimisation of MV photon dose distributions when using advanced algorithms: proof of concept and potential applications
Authors: Jurado-Bruggeman Diego , Muñoz-Montplet Carles , Vilanova Joan C
Published: September 2020

Advanced algorithms used in MV photon radiotherapy model radiation transport in any media. They represent a step forward but introduce new uncertainties and questions, including whether to report the doses to water (Dw,m) or medium (Dm,m) voxels, and the impact of fluence changes introduced by surrounding media. These aspects can compromise consistency between both reporting modes and with previous algorithms in which clinical experience is based. This study introduces a new dose quantity, the dose-to-reference-like medium, to overcome the aforementioned shortcomings. It is linked to a reference medium, water in this study (Dw,m*), and defined as the absorbed dose in a voxel of this reference medium surrounded by a reference-like medium with the same radiation transport characteristics as the original one. We propose to derive Dw,m* distributions by post-processing Dw,m or Dm,m applying a correction factor (CF) to each voxel which depends on its composition. We present and justify a simple and straightforward method to obtain CFs that only involves two phantoms with the same density: one with the considered composition and the other with that of the reference medium. A proof of concept was performed in a clinical environment for Acuros XB (AXB) advanced algorithm and 6 MV photon beams. The CFs were derived for the tissues characterised in Acuros. Dw,m* was compared to Dw,m, Dm,m, and Dw,w from AAA analytical algorithm for some virtual and clinical cases. All the previous quantities presented limitations that can be solved by Dw,m*. This new quantity allows the applicability of evaluation parameters, traceability to clinical experience, and isolation of heterogeneity effects to identify optimum plans, offering useful characteristics for plan evaluation and optimisation in clinical practice. Additionally, it also has potential applications in automated treatment planning and multi-centre activities such as clinical trials, audits, benchmarking, and shared models for automation.
RegQCNET: Deep quality control for image-to-template brain MRI affine registration
Authors: Denis de Senneville Baudouin , Manjón José V , Coupé Pierrick
Published: September 2020

Affine registration of one or several brain image(s) onto a common reference space is a necessary prerequisite for many image processing tasks, such as brain segmentation or functional analysis. Manual assessment of registration quality is a tedious and time-consuming task, especially in studies comprising a large amount of data. Automated and reliable quality control (QC) becomes mandatory. Moreover, the computation time of the QC must be also compatible with the processing of massive datasets. Therefore, automated deep neural network approaches have emerged as a method of choice to automatically assess registration quality.

In the current study, a compact 3D convolutional neural network, referred to as RegQCNET, is introduced to quantitatively predict the amplitude of an affine registration mismatch between a registered image and a reference template. This quantitative estimation of registration error is expressed using the metric unit system. Therefore, a meaningful task-specific threshold can be manually or automatically defined in order to distinguish between usable and non-usable images.

The robustness of the proposed RegQCNET is first analyzed on lifespan brain images undergoing various simulated spatial transformations and intensity variations between training and testing. Secondly, the potential of RegQCNET to classify images as usable or non-usable is evaluated using both manual and automatic thresholds. During our experiments, automatic thresholds are estimated using several computer-assisted classification models (logistic regression, support vector machine, Naive Bayes and random forest) through cross-validation. To this end we use an expert’s visual QC estimated on a lifespan cohort of 3953 brains. Finally, the RegQCNET accuracy is compared to usual image features such as image correlation coefficient and mutual information.

The results show that the proposed deep learning QC is robust, fast and accurate at estimating affine registration error in the processing pipeline.
Emitter-site specificity of hard x-ray photoelectron Kikuchi-diffraction
Authors: Fedchenko O , Winkelmann A , Chernov S , Medjanik K , Babenkov S , Agustsson S Y , Vasilyev D , Hoesch M , Elmers H-J , Schönhense G
Published: September 2020

High-resolution full-field imaging of (k

x
, k

y
) photoelectron distributions (k-resolution 0.03 Å−1, angular resolution 0.03° at 6.7 keV) in a large field of view (up to 16 Å−1 dia.) allows to observe fine details in Kikuchi-type diffractograms. Alongside with the element specificity via core-level spectra, this method opens a new avenue to structural analysis using hard x-ray photoelectron diffraction (hXPD). Here we present a theoretical study of the emitter-site specificity by simulating hXPD patterns for arbitrary positions of emitter atoms in the unit cell. Using the Bloch wave approach to photoelectron diffraction from lattice planes, the diffraction patterns from a number of positions in the unit cell can be obtained simultaneously exploiting the reciprocity theorem. Simulations for dopant atoms and dopant multimers (dimers, trimers, clusters) in the Si lattice at various positions in the unit cell reveal a strong site-sensitivity in terms of dramatic changes in the diffraction patterns with emitter-atom position. The results are compared with measurements for Si hyperdoped with Te.
O-GlcNAcylation inhibits the oligomerization of alpha-synuclein by declining intermolecular hydrogen bonds through a steric effect
Authors: Wu Kai , Li Dechang , Xiu Peng , Ji Baohua , Diao Jiajie
Published: September 2020

Toxic abnormal aggregation of α-synuclein (α-Syn) is a feature of Parkinson’s disease. Several biochemical and biophysical studies have demonstrated that many post-translational modifications (PTM) of α-Syn could distinctly alleviate its oligomerization-mediated toxicity. Recently, a compelling link is emerging between the PTM O-GlcNAcylation (O-GlcNAc) and protein aggregation, yet the underlying molecular mechanism remains unclear. Based on the all-atom molecular dynamics simulations, we found that O-GlcNAc modifications can suppress the process of oligomerization of α-Syn aggregates via a steric effect—the additional O-linked glycosyl group disrupts the formation of hydrogen bonds (H-bonds) between α-Syn monomers. Besides, we proposed a theoretical model to further capture the physical mechanism of α-Syn aggregation/disaggregation in the absence/presence of O-GlcNAc-modified α-Syn. Our findings unveil the molecular mechanism of the O-GlcNAc-induced inhibition of α-Syn oligomerization, which may help to understand how O-GlcNAc prevents the oligomerization of other proteins and provides the guideline for the development of O-GlcNAc-based therapeutic strategies in neurodegenerative diseases.