bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute COVID-19 Infection in a Pediatric Patient with ROHHAD
Authors: Udrea Daniel S. , Lopez Merrick , Avesar Michael , Qureshi Sonea , Moretti Anthony , Abd-Allah Shamel A. , Chandnani Harsha K.
Published: October 2020

The novel coronavirus (severe acute respiratory syndrome coronavirus-2) has led to a global pandemic. In the adult population, coronavirus disease 2019 (COVID-19) has been found to cause multiorgan system damage with predicted long-term sequelae. We present a case of a 10-year-old boy with a history of ROHHAD (rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation) who presented with hypoxia, emesis, and abdominal pain. Imaging found bilateral ground glass opacities in the lungs and a pericardial effusion. Laboratory evaluation was concerning for elevated inflammatory markers. Remdesivir, hydroxychloroquine, and anticoagulation (heparin and enoxaparin) were utilized. The patient's severe respiratory failure was managed with conventional mechanical ventilation, inhaled nitric oxide, and airway pressure release ventilation. We hope that this report provides insight into the course and management of the severe acute pediatric COVID-19 patient, specifically with underlying comorbidities such as ROHHAD. Clinical trial registration is none.
Modeling a Pandemic (COVID-19) Management Strategy for Urban Slums Using Social Geometry Framework
Authors: Onditi Francis , Obimbo Moses , Muchina Samson Kinyanjui , Nyadera Israel
Published: October 2020

The purpose of this paper is to utilize social geometry framework to model a pandemic (COVID-19) management strategy in densely populated informal settlements in Kenya. Our central claim is that the containment strategy that was instituted to control spread of COVID-19 failed to recognize the socio-cultural and livelihood complexities of the urban slum residents. This unmitigated strategy predisposed the residents to risks of heightened transmission of the pandemic. Drawing on social geometry approach in the analysis of human relations, we reveal some insights offered by our experiences in theorizing about public health intervention (PHI) and in doing so develop an alternative analytical framework (‘social pendulum’) to support the development of a PHI strategy that is compatible with the swing-like lifestyle of residents in the informal settlements. Our conclusion revisits the reliability and validity criteria for the new framework and offers some direction for further research.
Simulations suggest graphite may deform coronaviruses and limit their spread
Authors: Johnson-Groh Mara
Published: October 2020

Computer simulations of SARS-CoV-2 glycoprotein spikes hint some nanomaterials could potentially deform the virus and help slow its spread.
Simulating sticky particles: A Monte Carlo method to sample a stratification
Authors: Holmes-Cerfon Miranda
Published: October 2020

Many problems in materials science and biology involve particles interacting with strong, short-ranged bonds that can break and form on experimental timescales. Treating such bonds as constraints can significantly speed up sampling their equilibrium distribution, and there are several methods to sample probability distributions subject to fixed constraints. We introduce a Monte Carlo method to handle the case when constraints can break and form. More generally, the method samples a probability distribution on a stratification: a collection of manifolds of different dimensions, where the lower-dimensional manifolds lie on the boundaries of the higher-dimensional manifolds. We show several applications of the method in polymer physics, self-assembly of colloids, and volume calculation in high dimensions.
Proton conduction in inkjet-printed reflectin films
Authors: Lu Yujia , Pratakshya Preeta , Chatterjee Atrouli , Jia Xiaoteng , Ordinario David D. , Phan Long , Cerna Sanchez Juana A. , Kautz Rylan , Tyagi Vivek , Patel Priyam , Van Dyke Yegor , Dao MyAnh K. , Kerr Justin P. , Long James , Allevato Alex , Leal-Cruz Jessica , Tseng Eric , Peng Ethan R. , Reuter Andrew , Couvrette Justin , Drake Samantha , Omenetto Fiorenzo G. , Gorodetsky Alon A.
Published: October 2020

Biomolecular proton conducting materials have been touted as promising for seamlessly and directly interfacing natural biological systems with traditional artificial electronics. As such, proton conduction has been explored for a variety of protein- and polypeptide-based materials. Within this context, cephalopod structural proteins called reflectins have demonstrated several favorable properties, including outstanding electrical figures of merit as proton conductors and intrinsic biocompatibility with cellular systems. However, the processing of reflectins into films has typically used low-throughput material-intensive strategies and has often required organic solvents. Herein, we report the preparation of devices from active layers fabricated via inkjet printing of reflectin solubilized in water and the systematic evaluation of their electrical performance. Taken together, our findings represent a step forward in the manufacturing and development of unconventional bioelectronic platforms from the reflectin family of proteins.
Biostable conductive nanocomposite for implantable subdermal antenna
Authors: Curry Franky , Chrysler Andrew M. , Tasnim Tasmia , Shea Jill E. , Agarwal Jayant , Furse Cynthia M. , Zhang Huanan
Published: October 2020

Current antennas used for communication with implantable medical devices are connected directly to the titanium device enclosure, but these enclosures are shrinking as batteries and circuits become smaller. Due to shrinking device size, a new approach is needed that allows the antenna to extend beyond the battery pack, or to be entirely separate from it. Softer properties are needed for antennas in direct contact with body tissues. This must be achieved without compromising the high electrical conductivities and stabilities required for acceptable performance. Here, a nanocomposite based approach was taken to create soft, biocompatible antennas that can be embedded in the fat layer as an alternative to the metallic antennas used today. The nanocomposite films combine the exceptional electrical conductivity, biocompatibility, and biostability of Au nanoparticles with the mechanical compliance, biocompatibility, and low water permeability of polyurethane. Nanocomposite film synthesis utilized flocculation and vacuum assisted filtration methods. The soft antenna films display high conductivities (∼103 S/m–105 S/m), reduced Young’s moduli (∼102 MPa–103 MPa), exceptional biocompatibilities characterized by in vivo and in vitro work, and notable biostabilities characterized by accelerated degradation studies. Consequently, the nanocomposite antennas are promising for chronic in vivo performance when the conductivity is above 103 S/m.
Temperature dependence of reconfigurable bandstop filters using vanadium dioxide switches
Authors: Muller Andrei A. , Cavalieri Matteo , Ionescu Adrian M.
Published: October 2020

In this Letter, we report and investigate the temperature dependency of various radio frequency (RF) parameters for a fabricated reconfigurable bandstop filter with vanadium dioxide (VO2) switches measured up to 55 GHz. Here, the insulator-to-metal (ITM) and metal-to-insulator transition (MIT) hysteresis of the VO2 thin film influence on the RF characteristics of the filters is analyzed from 25 °C and 120 °C in heating and cooling. The resonance frequency and maximum insertion loss (IL) stability and sensitivity with temperature variations are explored. It is noticed that increasing the temperature to 50 °C from 25 °C (or decreasing it to 50 °C from 120 °C) will result in a less than 1% fractional frequency shift with respect to the off and on resonance frequencies. The sharp DC conductivity level variations of the VO2 thin film around the transition temperatures translate into sharp effects on the resonance characteristics of the filters. On the contrary, the maximum IL levels are less sensitive to the sharp conductivity changes of DC films around the VO2 transition temperature. A unique behavior is reported when successively heating-up and cooling-down, over and below, respectively, the transition temperature of VO2: the fabricated filter exhibits completely different resonance frequencies. This suggests that in the temperature dependence of the VO2 RF design, the practical use of reconfigurable RF functions has to take into account the history of thermal effects and increase or decrease in the device temperature when crossing the IMT/MIT transition point.
Electronic interface and charge carrier density in epitaxial graphene on silicon carbide. A review on metal–graphene contacts and electrical gating
Authors: Aslanidou Sofia , García-García Alberto , Godignon Philippe , Rius Gemma
Published: October 2020

For over 15 years, the number of studies on graphene electronics has not ceased growing. The rich physics, a set of outstanding properties, and the envisioned range of potential applications have consolidated graphene as a research field in its own. In this Research Update, we address a specific case of graphene for electronics, epitaxial graphene on silicon carbide (SiC) substrates. This paper mainly focuses on the electronic interface of graphene with metals. The first part of this paper describes the most characteristic aspects of the growth of epitaxial graphene on SiC wafers, and the main techniques for graphene material characterization are presented first. The main objective of this paper is to gather and discuss the most representative studies on the graphene–metal interface and the strategies employed to obtain low values for the contact resistances, which is a key feature for achieving the best performance of any graphene electronic devices. To benchmark developments in specifically epitaxial graphene on SiC, we include the results on mechanically exfoliated graphene from HOPG, as well as chemical vapor deposition graphene. In the last part of this paper, relevant device architectures for electrically gating graphene are briefly discussed.
Control of vortex shedding from two side-by-side cylinders using a pair of tangential jets
Authors: Yuan Fangyang , Cao Yang , Tu Chengxu , Lin Jianzhong
Published: October 2020

The active control of two side-by-side cylinder wakes by tangential jets with a Reynolds number of 3900 and a pitch ratio of 1.1 was studied experimentally and numerically. The particle image velocimetry technique was used to obtain the flow around side-by-side cylinders in a wind tunnel, and the dynamic lift on the cylinder was measured by a three-axis force-sensor. A numerical model was set up for comparison with the experimental data. The effects of the jet angles and jet intensities on the wake control were discussed. It was found that the flow structure was bistable biased flow and that the gap flow led to an asymmetry of the flow field. Tangential jets with angles smaller than 20° were ineffective in controlling the wake and suppressing the vortex-induced vibrations of the cylinders. Tangential jets with angles larger than 45° induced a reverse vortex and were not suitable to be applied. The vortex flow region became smaller with an increase in the jet momentum coefficient but needed additional power supply. A moderate jet angle of 45° with a jet momentum coefficient of 0.218 demonstrated the best control effect in which the shedding vortex could be controlled in a small triangle region behind the cylinders (X ≦ 1.5D). The peak amplitude of the cylinder lift power spectral density (PSD) can be reduced to ∼8.7% of the PSD without the control. Effective control via the use of tangential jets provides a theoretical basis for subsequent active closed-loop control.
Anisotropic avalanche dynamics during ferroelectric switching in BaTiO3 and 0.7Pb(Mg2/3Nb1/3)O3–0.3PbTiO3
Authors: Xu Yangyang , Zhou Yumei , Xue Dezhen , Ding Xiangdong , Sun Jun , Salje E. K. H.
Published: October 2020

A ferroelectric hysteresis depends on the orientation of the applied field with respect to the spontaneous polarization. The ferroelectric switching occurs through correlated domain movements forming avalanches. We tested whether avalanches in single crystals of the prototypic ferroelectric BaTiO3 and the relaxor ferroelectric 0.7Pb(Mg2/3Nb1/3)O3–0.3PbTiO3 show anisotropic field dependences. The anisotropy of the energy exponent of avalanches is very small in BaTiO3 with exponents between 1.53 and 1.6, which is remarkably close to the prediction of mean field theory 5/3. The anisotropy is much stronger in 0.7Pb(Mg2/3Nb1/3)O3–0.3PbTiO3 with one exponent slightly above the typical range of mean field values (4/3–5/3): 1.43 ± 0.02, 1.64 ± 0.03, and 1.79 ± 0.03 for fields along [100], [110], and [111], respectively. This anisotropy indicates a variation of the fractal dimensions of the transient domain patterns depending on the direction of the switching field.
Local coordination numbers of up to 19 in gadolinium–tin alloy nanoclusters
Authors: Fuchs Thomas M. , Gleditzsch Martin , Schäfer Rolf
Published: October 2020

A combined approach based on quantum–chemical calculations and molecular beam experiments demonstrates that in isolated nanoalloy clusters of type GdSnN, a total number of N = 19 tin atoms can be arranged around a central gadolinium atom. While the formation of the first coordination shell is incomplete for clusters with less than 15 tin atoms, the second coordination sphere starts to form for cluster sizes of more than 20 tin atoms. The magnetic properties of the clusters reveal that the tin atoms not only provide a hollow cage for Gd but also are chemically bound to the central atom. The calculated spin densities imply that an electron transfer from Gd to the tin cage takes place, which is similar to what is observed for endohedral metallofullerenes. However, the measured electric dipole moments indicate that in contrast to metallofullerenes, the Gd atom is located close to the center of the tin cage.
Dry-wet hybrid deposition of wide-bandgap mixed-halide perovskites for tandem solar cell applications
Authors: Kanbe Shota , Kagae Junta , Murota Ayane , Hara Yuya , Fujiwara Kentaro , Yamashita Kenichi
Published: October 2020

The tandem architecture of solar cells is expected to be one of the promising strategies for further improving the performance of photovoltaic devices. While a dry-wet hybrid deposition method is highly promising for fabricating perovskite top cells on textured silicon bottom cells, the bandgap tunability of this deposition method has not been investigated in detail. Here, we show the systematic investigation on mixed-halide perovskite films fabricated by the dry-wet hybrid deposition method on a PbBr2 underlayer. The thermally deposited PbBr2 underlayer is demonstrated to be beneficial for promoting reaction with an organic halide precursor solution, resulting in a dense morphology with large perovskite grains. Furthermore, the hybrid deposition method is also shown to be a straightforward way for wide-range bandgap tuning as it can facilitate halogen mixing. These findings provide useful guidelines for further improving the power conversion efficiency of multijunction tandem solar cell devices.
Comparative analysis of characteristics of a supersonic cw chemical HF laser on molecular fluorine and nitrogen trifluoride
Authors: Fedorov I.A.
Published: October 2020

We have experimentally studied the characteristics of a supersonic cw chemical HF laser with a flat nozzle array based on a nozzle – nozzle reagent mixing scheme operating with the use of F2 – D2 – He and NF3 – D2 – He fuel compositions in an atomic fluorine generator. The active medium flow field pattern, its gas-dynamic characteristics, and the laser radiation spectrum are considered. The comparison of these characteristics has made it possible to establish a strong impact on the flow field (lasing zone length) of the chemical composition of the combustion products from the atomic fluorine generator. The gas-dynamic parameters of the active medium formed by using a NF3 – D2 – He fuel have turned out to be less acceptable in terms of the gas flow pressure recovery than in the case of F2 – D2 – He fuel, while the radiation spectrum was more preferable from the viewpoint of passing through the atmosphere.
Photoacoustic methane gas analyser based on a 3.3-μm optical parametric oscillator
Authors: Sherstov I.V. , Kolker D.B.
Published: October 2020

We demonstrate a bench-scale prototype of a photoacoustic (PA) methane gas analyser that takes advantage of an optical parametric oscillator (OPO) based on a fan-out MgO : PPLN structure and resonant differential PA detector. The OPO emits in a repetitively pulsed mode (∼1750 Hz) at an idler wavelength of ∼3.3 μm with an average power of ∼40 – 50 mW. Using the prototype laser PA gas analyser, we experimentally demonstrate the feasibility of measuring the background methane concentration in air (∼2 – 3 ppm of CH4). The threshold sensitivity of the PA gas analyser (1σ) is determined to be ∼ 49 ppb of CH4.
Decay of a laser beam under stimulated temperature scattering in toluene as a result of two-photon pump absorption and nonsteady-state laser pulse interaction with matter
Authors: Gordeev A.A. , Efimkov V.F. , Zubarev I.G. , Mikhailov S.I.
Published: October 2020

The decay of the pump-beam spatial structure under conditions of stimulated temperature scattering of a pulsed laser beam in toluene as a result of two-photon absorption of pump radiation and time-dependent interaction of a laser pulse with a medium is considered.
Triple integrated laser – thyristor
Authors: Bagaev T.A. , Ladugin M.A. , Padalitsa A.A. , Marmalyuk A.A. , Kurnyavko Yu.V. , Lobintsov A.V. , Danilov A.I. , Sapozhnikov S.M. , Krichevskii V.V. , Konyaev V.P. , Simakov V.A. , Slipchenko S.O. , Podoskin A.A. , Pikhtin N.A.
Published: October 2020

A triple laser – thyristor, i. e., a semiconductor laser with three emitting sections monolithically integrated with an electronic switch (thyristor) is experimentally studied. For comparison, the output characteristics of single and double laser – thyristors are presented. It is shown that the functional integration of a laser with a thyristor in one heterostructure allows the laser to efficiently operate in a pulsed regime (output power ∼50 W), the use of vertical integration of two laser sections increases the power to ∼90 W, and the integration of three laser sections makes it possible to increase the output optical power to ∼120 W with all other conditions being the same.
Professional interpreting translation education in the Chinese mainland
Authors: Zhong Weihe , Zhao Tianyuan , Xu Mianjun
Published: October 2020

This paper reviews the history and achievements of professional interpreting and translation education in the
Chinese mainland since 1979, discusses the internal and external challenges it faces in the new era and puts forward some measures
to accelerate and upgrade its development so as to offer some insights for the future development of translation education in
China and beyond. It is hoped that this paper will enable interpreting and translation teachers and scholars around the world to
better understand the achievements and status quo of professional interpreting and translation education in the Chinese mainland
and will enhance understanding, communication and exchanges of the interpreting and translation education circle
internationally.
Does culture translate?
Authors: Shormani Mohammed Q.
Published: October 2020

This study strives to answer one major question: Does culture translate?, employing the translation of English
proverbs into Arabic by senior students majoring in English. The study involves 30 English proverbs collected from different
sources, based on three criteria, namely complete Arabic equivalence, partial Arabic equivalence and zero Arabic equivalence.
These 30 proverbs were distributed to 20 randomly selected senior students as participants. The participants translated the 30
proverbs in the form of a translation test in two phases. The results of the study show that teaching the cultural aspects of the
proverbs has developed and improved the participants’ translations considerably, thus providing empirical evidence that
culture translates.
Supplementary comparison EURAMET EM-S41 bilateral comparison of DC voltage reference standards (1,018 V and 10 V) (EURAMET.EM-S41)
Authors: Blanc Isabelle , Sardjono Hadi , Syahadi Mohamad
Published: October 2020

This report describes a bilateral comparison of DC voltage standards organised within the frame of the EU-Indonesia Trade Support Program II n° APE12-06b between LNE, France and KIMLIPI, Indonesia. This bilateral comparison registered in the KCDB as EURAMET.EM-S41 was piloted by LNE. LNE participated in EUROMET comparison N° 429, designated EUROMET.EM.BIPM-K11 thus providing the link between KIM-LIPI results and CCEM-K11. This report includes the measurement results from the participants and information about their calibration methods for measurements of 1,018 V and 10 V.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Resonant x-ray absorption of strong-field-ionized CF3Br
Authors: Fouda A E A , Ho P J , Dunford R W , Kanter E P , Krässig B , Young L , Peterson E R , Landahl E C , Pan L , Beck D R , Southworth S H
Published: October 2020

We report on an experimental and theoretical study of strong-field laser ionization of CF3Br followed by resonant x-ray absorption at the Br K-edge. Distinct 1s → 4p, 5p Rydberg transitions of Br
q+ (q = 1–4) atomic ions are observed and identified with Hartree–Fock–Slater and relativistic configuration interaction calculations. Time-dependent density functional theory and ab initio molecular dynamics calculations were performed to simulate the dissociative ionization process and the molecular orbitals for the q = 1–4 charge states. Measurements were made with both parallel and perpendicular linear polarizations of the laser and x-rays, but dichroism was not observed, indicating negligible alignment by the laser ionization process. This result is explained by calculations on atomic Br and the molecular simulation.
Coriolis contribution to excited states of odd-mass nuclei with different deformation-dependent mass coefficients
Authors: Ait Ben Hammou A , Oulne M
Published: October 2020

Within the collective Bohr Hamiltonian, the adoption of a mass tensor as a function of collective coordinates has demonstrated its importance for describing the structure of nuclei. On the other hand, for odd-mass nuclei, the Coriolis interaction between the rotational and single-particle motions affects significantly the structure of nuclear excited states. In the framework of a recently developed extended Bohr Hamiltonian, by considering the deformation-dependent mass formalism whith different mass parameters for the rotation and the two β and γ vibrations and taking into account the Coriolis contribution, we investigate the bands structure of the 173Yb, 163Dy, 155Eu and 153Eu nuclei. Excited-state energies and B(E2) transition probabilities are calculated and compared with the available experimental data. Besides, we investigate the effect of DDMF and the Coriolis force on nuclear observables.
Aggregation of methacrylate-based ternary biomimetic antimicrobial polymers in solution
Authors: Rani Garima , Kuroda Kenichi , Vemparala Satyavani
Published: October 2020

Using detailed atomistic simulations, we explore the morphological characteristics of aggregates formed in solution phase by ternary biomimetic antimicrobial (AM) methacrylate polymers, composed of hydrophobic, charged cationic and polar functional groups and compare it with aggregate morphologies of binary methacrylate polymers, composed only of hydrophobic and charged cationic functional groups. The effect of sequence of the constituent functional groups on aggregate conformation is also studied by considering random and block sequences along the polymer backbone. Our results show that while binary polymers tend to form robust aggregates, replacing some of the hydrophobic groups with overall charge neutral polar groups weakens the aggregate considerably, leading to increased conformational fluctuations and formation of loose-packed, open aggregates, particularly in the case of random ternary polymers. Interaction energy calculations clearly suggest that the role of inclusion of polar groups in ternary polymers is two-fold: (1) to reduce possible strong local concentration of hydrophobic groups and ‘smear’ the overall hydrophobicity along the polymer backbone to increase the solubility of the polymers (2) to compensate the loss of attractive hydrophobic interactions by forming attractive electrostatic interactions with the charged groups and contribute to aggregation formation, albeit weak. Given that most of the naturally occurring AM peptides have contributions from all the three functional groups, this study elucidates the functionally tuneable role of inclusion of polar groups in the way AM agents interact with each other in solution phase, which can eventually dictate their partitioning behaviour into bacterial and mammalian membranes.
Impact of defects on photoexcited carrier relaxation dynamics in GeSn thin films
Authors: Kondratenko S V , Derenko S S , Mazur Yu I , Stanchu H , Kuchuk A V , Lysenko V S , Lytvyn P M , Yu S-Q , Salamo G J
Published: October 2020

We report the results of a study that was conducted to investigate the recombination paths of photoexcited charge carriers in GeSn thin films. The charge carrier lifetime was predicted as a function of temperature from a description of photoconductivity transients, assuming co-influence of Shockley–Read–Hall and radiative carrier recombination paths. We identify that dislocations are the source of a band of electronic states with the highest occupied state at E
V + (85÷90) meV that acts as Shockley–Read–Hall centers determining the charge carrier lifetime. The photoluminescence (PL) and photoconductivity spectroscopy have been applied to distinguish between the contribution of both band-to-band and dislocation-related electron transitions. The PL band was found to demonstrate a low-energy shift of about 80 ± 20 meV relative to the edge of the photoconductivity spectra in the indirect bandgap GeSn films with dislocations. The role of a different nature deeper acceptor level at E
V + (140 ÷ 160) meV in the recombination processes of the GeSn layers with better structural quality and the Sn content higher than 4% was discussed. This detailed understanding of the recombination processes is of critical importance for developing GeSn/Ge-based optoelectronic devices.
A cascaded difference frequency generation method combined with cavity phase matching and quasi phase matching for high-efficiency terahertz generation
Authors: Shijia Zeng , Zhiming Rao , Wenjiang Tan , Enshuai Zhang
Published: October 2020

A cascaded difference frequency generation (DFG) method for high-efficiency terahertz generation is presented, which is combined with cavity phase matching and quasi phase matching. The results show that a ten-orders cascade effect can be approximately satisfied, with a peak photon conversion efficiency of 447.6%, which exceeds the Manley-Rowe limit. This method is expected to contribute to improving the conversion efficiency of DFG for terahertz generation.
Polarization-independent reflection grating in second-order Littrow for high laser resolving power
Authors: Fang Jimin , Wang Bo
Published: October 2020

In order to obtain a grating solution for high laser resolving power, a multilayer fused-silica reflection grating is described with a silver layer embedded in the groove in second-order Littrow configuration instead of first-order mounting. Efficiencies of 96.17% and 96.14% can diffracted in −2nd order for TE and TM polarizations, which are greater than 96%. The new multilayer reflection grating with a silver layer embedded has good incident characteristics and process tolerances. Therefore, the high-efficiency output with polarization-independent and wideband property characteristics of the grating will be well applied to the laser field.
Ionization of two-electron atom (xenon) studied by Bohmian mechanics theory*
Authors: Song Yang , Han Shu , Yang Yu-Jun , Guo Fu-Ming , Li Su-Yu
Published: October 2020

The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics (BM) theory, and the xenon atomic potential function is used as a model. The single ionization process and double ionization process are calculated by the BM theory and their results are in good agreement with those calculated by numerically solving the time-dependent Schrödinger equation. The analyses of the types, trajectories, and forces of Bohmian particles (BPs) undergoing the single and double ionizations indicate that the re-collision process accounts for a considerable proportion in the singly ionized cases. Furthermore, the analysis of the work done by the external force acting on the BPs shows that the quantum force plays an important role in the re-collision process. This work is helpful in understanding the ionization of two-electron atom in an intense laser field.
D → P(π, K) helicity form factors within light-cone sum rule approach *
Authors: Fu Hai-Bing , Cheng Wei , Zhou Rui-Yu , Zeng Long
Published: October 2020

In this study,

helicity form factors (HFFs) are investigated by applying the QCD light-cone sum rule (LCSR) approach. The calculation accuracy is up to the next-to-leading order (NLO) gluon radiation correction of twist-(2,3) distribution amplitude. The resultant HFFs at a large recoil point are

and

, in which the contributions from the three particles of the leading order (LO) are so small that they can be safely neglected. The maximal contribution of the NLO gluon radiation correction for

is less than 3%. After extrapolating the LCSR predictions for these HFFs to the whole

-region, we obtain the decay widths for semileptonic decay processes

, which are consistent with the BES-III collaboration predictions within error limits. After considering the

-meson lifetime, we give the branching fractions of

with

; our predictions also agree with the BES-III collaboration results within error limits, especially for the

decay process. Finally, we present the forward-backward asymmetry

and lepton convexity parameter

, and further calculate the mean value of these two observations,

and

, which may provide a way to test those HFFs in future experiments.
Top rare decays t→cV in mirror twin Higgs models *
Authors: Bie Su-Ya , Liu Guo-Li , Wang Wenyu
Published: October 2020

The decay

(

) processes in mirror twin Higgs models with colorless top partners are studied in this paper. We report that the branching ratios of these decays can strongly affect the standard model expectations in some parameter spaces and may be detectable according to the current precision electroweak measurements. Thus, constraints on the model parameters may be obtained from the branching fraction of the decay processes, which may serve as a robust detection tool for this new physics model.
Uncovering the dynamics of correlation structures relative to the collective market motion
Authors: Heckens Anton J , Krause Sebastian M , Guhr Thomas
Published: October 2020

The measured correlations of financial time series in subsequent epochs change considerably as a function of time. When studying the whole correlation matrices, quasi-stationary patterns, referred to as market states, are seen by applying clustering methods. They emerge, disappear or reemerge, but they are dominated by the collective motion of all stocks. In the jargon, one speaks of the market motion, it is always associated with the largest eigenvalue of the correlation matrices. Thus the question arises, if one can extract more refined information on the system by subtracting the dominating market motion in a proper way. To this end we introduce a new approach by clustering reduced-rank correlation matrices which are obtained by subtracting the dyadic matrix belonging to the largest eigenvalue from the standard correlation matrices. We analyze daily data of 262 companies of the S&P 500 index over a period of almost 15 years from 2002 to 2016. The resulting dynamics is remarkably different, and the corresponding market states are quasi-stationary over a long period of time. Our approach adds to the attempts to separate endogenous from exogenous effects.
Exploration of swimming performance for a biomimetic multi-joint robotic fish with a compliant passive joint
Authors: Chen Di , Wu Zhengxing , Dong Huijie , Tan Min , Yu Junzhi
Published: October 2020

In this paper, a novel compliant joint with two identical torsion springs is proposed for a biomimetic multi-joint robotic fish, which enables imitatation of the swimming behavior of live fish. More importantly, a dynamic model based on the Lagrangian dynamic method is developed to explore the compliant passive mechanism. In the dynamic modeling, a simplified Morrison equation is utilized to analyze the hydrodynamic forces. Further, the parameter identification technique is employed to estimate numerous hydrodynamic parameters. The extensive experimental data with different situations match well with the simulation results, which verifies the effectiveness of the obtained dynamic model. Finally, motivated by the requirement for performance optimization, we firstly take advantage of a dynamic model to investigate the effect of joint stiffness and control parameters on the swimming speed and energy efficiency of a biomimetic multi-joint robotic fish. The results reveal that phase difference plays a primary role in improving efficiency and the compliant joint presents a more significant role in performance improvement when a smaller phase difference is given. Namely, at the largest actuation frequency, the maximum improvement of energy efficiency is obtained and surprisingly approximates 89%. Additionally, the maximum improvement in maximum swimming speed is about 0.19 body lengths per second. These findings demonstrate the potential of compliance in optimizing joint design and locomotion control for better performance.
Evaluating heat extremes in the UK Climate Projections (UKCP18)
Authors: Kennedy-Asser A T , Andrews O , Mitchell D M , Warren R F
Published: October 2020

In recent years, UK summer heatwaves have resulted in thousands of excess deaths, with both extreme temperatures and high humidity increasing health risks. Here, the UK Climate Projections 2018 (UKCP18) are compared to observational (HadUK-Grid) and reanalysis data (ERA5) to quantify model performance at capturing mean, extremes (95th to 99.5th percentiles) and variability in the climate state and heat stress metrics (simplified wet bulb global temperature, sWBGT; Humidex; apparent temperature). Simulations carried out for UKCP18 generally perform as well as or better than CMIP5 models in reproducing observed spatial patterns of UK climate relating to extreme heat, with RMSE values on average ∼30% less than for the CMIP5 models. Increasing spatial resolution in UKCP18 simulations is shown to yield a minor improvement in model performance (RMSE values on average ∼5% less) compared to observations, however there is considerable variability between ensemble members within resolution classes. For both UKCP18 and CMIP5 models, model error in capturing characteristics of extreme heat generally reduces when using heat stress metrics with a larger vapour pressure component, such as sWBGT. Finally, the 95th percentile of observed UK summer temperature is shown to have ∼60% greater interannual variability than the summer mean over the recent past (1981–2000). This effect is underestimated in UKCP18 models (∼33%) compared to HadUK-grid and ERA5. Compared to projected future changes in the global mean temperature, UK summer mean and 95th percentile temperatures are shown in increase at a faster rate than the global mean.
Effect of platinum and pre-oxidation on the hot corrosion behavior of aluminide coating with NaCl at 1050 °C
Authors: Peng Jubo , Huang Taihong , Song Peng , Huang Wenlang , He Yang , Ma Tao , Yang Bixiao , Liang Yuwei , Wu Minxuan , Chen Rong
Published: October 2020

The hot corrosion behaviors of the aluminide coatings with different treatments on the surface of Ni-based alloy at high temperature were investigated. The aluminide coating modified by three different methods (pretreatment, Pt-modification and both), and then all the specimens were oxidized in lab air with NaCl salt at 1050 °C. During cycle oxidation, oxide scales on the surface of the aluminide coatings presented different morphologies, composition and corrosion behaviors. The oxide scale on the surface of the as-received aluminide coating without any treatments showed a poor dense and a bad adherence. However, the oxide scale on the surface of the aluminide coating with both Pt-modification and pre-oxidation exhibited the best hot corrosion resistance. In the NaCl corrosion environment, different treatments resulted in different corrosion mechanisms. Without any treatments, the oxide scale with NaCl at high temperature occurred internal active oxidation, which could promote the corrosion process and form the pores in the oxide scale. The internal active oxidation also presented in the oxide scale on the surface of the aluminide coating with pre-oxidation.
Superconductivity in scandium borocarbide with orbital hybridization
Authors: Wu W , Li Y J , Zhang J H , Yu Z H , Liu Z Y , Zheng P , Yang H X , Dong C , Liu K , Xiang T , Luo J L
Published: October 2020

Exploration of superconductivity in light element compounds has drawn considerable attention because those materials can easily realize the high T
C superconductivity, such as LnNi2B2C (T
C = 17 K), MgB2 (T
C = 39 K), and very recently super-hydrides under pressure (T
C = 250 K). Here we report the discovery of bulk superconductivity at 7.8 K in scandium borocarbide Sc20BC27 with a tetragonal lattice which structure changes based on the compound of Sc3C4 with very little B doping. Magnetization and specific heat measurements show bulk superconductivity. An upper critical field of H
c2(0) ∼ 8 T is determined. Low temperature specific-heat shows that this system is a BCS fully gapped s-wave superconductor. Electronic structure calculations demonstrate that compared with Sc3C4 there are more orbital overlap and hybridization between Sc 3d electrons and 2p electrons of C-C(B)-C fragment in Sc20BC27, which form a new electric conduction path of Sc-C(B)-Sc. Those changes influence the band structure at the Fermi level and may be the reason of superconductivity in Sc20BC27.
The precipitation behavior and mechanical properties of Cu–Ni–Mn–Fe alloy during aging under elevated compression stresses
Authors: Shi Hao , Zou Juntao , Chen Jingren , Xiao Peng , Cao Fei , Liang Shuhua
Published: October 2020

The Cu–Ni–Mn–Fe alloy is prepared to study its precipitation behavior and mechanical properties during aging under elevated compression stresses. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), hardness and tensile tests are used for this investigation. The results indicate that the stress-aging treatment leads to the formation of fine, equiaxed grains and twins within the matrix of Cu–Ni–Mn–Fe alloy. During the stress-aging, the density of θ-MnNi precipitates initially decreases and then increases. The stress is further increased from 220 to 385 MPa, the vacancy concentration and dislocation density increase rapidly owing to creep deformation, while the strain-induced effect accelerates the precipitation of θ-MnNi. The results show that the tensile strength and hardness of Cu–Ni–Mn–Fe alloy initially decrease and then increase, and the tensile strength and hardness of the Cu–Ni–Mn–Fe alloy are 890 MPa and 274 HB under the compressive stress of 385 MPa, and the elongation remains at 8.72%. It is mainly attributed to the application of compression stresses during aging, which can enhance both the strength and ductility of the alloy.
Preparation of graphite phase carbon nitride (g-C3N4) micro-nano bouquet by thermal polymerization
Authors: Ma Feiwen , Ji Yuchun , Liu Bingsai , Wang Jilin , Zhou Bing , Zhen Guoyuan , Long Fei , Zou Zhengguang
Published: October 2020

A novel kind of g-C3N4 micro-nano bouquets were successfully prepared via a simple method using melamine and ammonium chloride as raw materials. X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), x-ray energy spectrometer (EDX), transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM),fourier transform infrared spectrometer (FT-IR) and x-ray photoelectron spectroscopy (XPS) were used to characterize the as-synthesized samples. The results indicated that the samples presented graphitic C3N4 micro-nano bouquets. Every microstructure was composed of many petals cross gathered along with the different directions. And the tip of every single petal contained quantities of nano bouquet structures with smaller diameters. In addition, abundant nanoparticles/nanorods distributed and intertwined together on the surface of the nano bouquet structure, and then formed cocoon-like porous morphology. Besides, based on the experimental results, the reasonable chemical reactions and the corresponding growth mechanism during the preparation process of g-C3N4 micro-nano bouquets were proposed. Finally, the UV–vis results showed that the sample was a wide band gap (about 3.11 eV) semiconductor.
Effect of thermal annealing on the optical stability of amorphous Ge–Se–Te films
Authors: Chen Jinbo , Qin Jingshuang , Zhang Limeng , Chen Yimin , Shen Xiang , Gu Jierong , Xu Tiefeng
Published: October 2020

Ge–Se–Te chalcogenide films with Ge content from 10% to 27% were prepared using thermal evaporation. The films were annealed with different times, and the changes of the linear refractive index and optical band gap of the films with different chemical compositions were investigated. It was found that, after 30 h of annealing, the Ge20Se8.5Te71.5 film exhibits the smallest change ratio in terms of linear refractive index (<0.5%), optical band gap (<1.5%), and thickness (<2.5%). Therefore, this component has the best optical stability in the Ge–Se–Te system studied in this paper. The optical band gap of Ge20Se8.5Te71.5 is about 0.8 eV, and the refractive index exceeds 3.4, which is beneficial to the applications in Te-based optical waveguide devices.
Inferring microenvironmental regulation of gene expression from single-cell RNA sequencing data using scMLnet with an application to COVID-19
Authors: Cheng Jinyu , Zhang Ji , Wu Zhongdao , Sun Xiaoqiang
Published: October 2020

Inferring how gene expression in a cell is influenced by cellular microenvironment is of great importance yet challenging. In this study, we present a single-cell RNA-sequencing data based multilayer network method (scMLnet) that models not only functional intercellular communications but also intracellular gene regulatory networks (https://github.com/SunXQlab/scMLnet). scMLnet was applied to a scRNA-seq dataset of COVID-19 patients to decipher the microenvironmental regulation of expression of SARS-CoV-2 receptor ACE2 that has been reported to be correlated with inflammatory cytokines and COVID-19 severity. The predicted elevation of ACE2 by extracellular cytokines EGF, IFN-γ or TNF-α were experimentally validated in human lung cells and the related signaling pathway were verified to be significantly activated during SARS-COV-2 infection. Our study provided a new approach to uncover inter-/intra-cellular signaling mechanisms of gene expression and revealed microenvironmental regulators of ACE2 expression, which may facilitate designing anti-cytokine therapies or targeted therapies for controlling COVID-19 infection. In addition, we summarized and compared different methods of scRNA-seq based inter-/intra-cellular signaling network inference for facilitating new methodology development and applications.
Drug repurposing for COVID-19: could vitamin C combined with glycyrrhizic acid be at play by the findings of Li et al.’s database-based network pharmacology analysis?
Authors: Huang Yu-Xi , Wang Wen-Xiao , Tang Yu-Ping , Yue Shi-Jun
Published: October 2020

The outbreak and pandemic of SARS-CoV-2 in 2019 has caused a severe public health burden and will challenge global health for the future. The discovery and mechanistic investigation of drugs against Coronavirus disease 2019 (COVID-19) is in deadly demand. The paper published by Li and colleagues proposed the hypothesis that vitamin C combined with glycyrrhizic acid in treating COVID-19 and its mechanistic investigation was performed by a database-based network pharmacology. In this letter, we present critical comments on the limitations and insufficiencies involved, from both the perspective of network pharmacology and current evidence on COVID-19.
C-C Chemokine receptor-like 2 (CCRL2) acts as coreceptor for human immunodeficiency virus-2
Authors: Islam Salequl , Moni Mohammad Ali , Urmi Umme Laila , Tanaka Atsushi , Hoshino Hiroo
Published: October 2020

Introduction

Most of the typical chemokine receptors (CKRs) have been identified as coreceptors for a variety of human and simian immunodeficiency viruses (HIVs and SIVs). This study evaluated CCRL2 to examine if it was an HIV/SIV coreceptor.

Methods

The Human glioma cell line, NP-2, is normally resistant to infection by HIV and SIV. The cell was transduced with amplified cluster of differentiation 4 (CD4) as a receptor and CCR5, CXCR4 and CCRL2 as coreceptor candidates to produce NP-2/CD4/coreceptor cells (). The cells were infected with multiplicity of infection (MOI) 1.0. Infected cells were detected by indirect immunofluorescence assay (IFA). Multinucleated giant cells (MGC) in syncytia were quantified by Giemsa staining. Proviral DNA was detected by polymerase chain reaction (PCR), and reverse transcriptase (RT) activity was measured.

Results

IFA detected viral antigens of the primary isolates, HIV-1HAN2 and HIV-2MIR in infected NP-2/CD4/CCRL2 cells, indicated CCRL2 as a functional coreceptor. IFA results were confirmed by the detection of proviral DNA and measurement of RT-activity in the spent cell supernatants. Additionally, MGC was detected in HIV-2MIR-infected NP-2/CD4/CCCRL2 cells. HIV-2MIR were found more potent users of CCRL2 than HIV-1HAN2. Moreover, GWAS studies, gene ontology and cell signaling pathways of the HIV-associated genes show interaction of CCRL2 with HIV/SIV envelope protein.

Conclusions

In vitro experiments showed CCRL2 to function as a newly identified coreceptor for primary HIV-2 isolates conveniently. The findings contribute additional insights into HIV/SIV transmission and pathogenesis. However, its in vivo relevance still needs to be evaluated. Confirming in vivo relevance, ligands of CCRL2 can be investigated as potential targets for HIV entry-inhibitor drugs.