bluuebunny/crossref_metadata_2025 huggingface dataset:
Drivers of benthic metacommunity structure along tropical estuaries
Authors: Alves Andreia Teixeira , Petsch Danielle Katharine , Barros Francisco
Published: February 2020

Community structure of many systems changes across space in many different ways (e.g., gradual, random or clumpiness). Accessing patterns of species spatial variation in ecosystems characterized by strong environmental gradients, such as estuaries, is essential to provide information on how species respond to them and for identification of potential underlying mechanisms. We investigated how environmental filters (i.e., strong environmental gradients that can include or exclude species in local communities), spatial predictors (i.e., geographical distance between communities) and temporal variations (e.g., different sampling periods) influence benthic macroinfaunal metacommunity structure along salinity gradients in tropical estuaries. We expected environmental filters to explain the highest proportion of total variation due to strong salinity and sediment gradients, and the main structure indicating species displaying individualistic response that yield a continuum of gradually changing composition (i.e., Gleasonian structure). First we identified benthic community structures in three estuaries at Todos os Santos Bay in Bahia, Brazil. Then we used variation partitioning to quantify the influences of environmental, spatial and temporal predictors on the structures identified. More frequently, the benthic metacommunity fitted a quasi-nested pattern with total variation explained by the shared influence of environmental and spatial predictors, probably because of ecological gradients (i.e., salinity decreases from sea to river). Estuarine benthic assemblages were quasi-nested likely for two reasons: first, nested subsets are common in communities subjected to disturbances such as one of our estuarine systems; second, because most of the estuarine species were of marine origin, and consequently sites closer to the sea would be richer while those more distant from the sea would be poorer subsets.
The association between an increase in glucose levels and armed conflict-related stress: A population-based study
Authors: Yitshak-Sade Maayan , Mendelson Nitsan , Novack Victor , Codish Shlomi , Liberty Idit F.
Published: February 2020

Studies have shown stress may lead to diabetes-related morbidities. In recent years during enhanced hostility periods, the population of Southern Israel experienced alert sirens and rocket fire on a daily basis. We investigated whether the exposure to these stressful circumstances, which peaked during three large military operations (MO), was associated with increased glucose levels among the civilian population. We included all fasting serum glucose tests taken between 2007–2014, of Clalit Health Services members in Southern Israel who had at least one fasting glucose test during an MO period and at least one test drawn at other times. We analyzed the association between MO periods and glucose using linear mixed-effects models. We included 408,706 glucose tests (10% during MO periods). Among subjects who reside in proximity to Gaza, glucose levels were 2.10% (95% CI 1.24%; 2.97%) higher in MO days compared to other times. A weaker effect was observed among subjects in more remote locations. In conclusion, we found stress to be associated with increased fasting glucose levels, especially among those who reside in locations in which the intensity of the threat is higher. Since glucose may be a marker of the population at cardiovascular risk, further studies are required.
Significant improvement in catalytic activity and enantioselectivity of a Phaseolus vulgaris epoxide hydrolase, PvEH3, towards ortho-cresyl glycidyl ether based on the semi-rational design
Authors: Zhang Chen , Liu Youyi , Li Chuang , Xu Yaohui , Su Yongjun , Li Jinping , Zhao Jun , Wu Minchen
Published: February 2020

The investigation of substrate spectrum towards five racemic (rac-) aryl glycidyl ethers (1a–5a) indicated that E. coli/pveh3, an E. coli BL21(DE3) transformant harboring a PvEH3-encoding gene pveh3, showed the highest EH activity and enantiomeric ratio (E) towards rac-3a. For efficiently catalyzing the kinetic resolution of rac-3a, the activity and E value of PvEH3 were further improved by site-directed mutagenesis of selected residues. Based on the semi-rational design of an NC-loop in PvEH3, four single-site variants of pveh3 were amplified by PCR, and intracellularly expressed in E. coli BL21(DE3), respectively. E. coli/pveh3E134K and /pveh3T137P had the enhanced EH activities of 15.3 ± 0.4 and 16.1 ± 0.5 U/g wet cell as well as E values of 21.7 ± 1.0 and 21.2 ± 1.1 towards rac-3a. Subsequently, E. coli/pveh3E134K/T137P harboring a double-site variant gene was also constructed, having the highest EH activity of 22.4 ± 0.6 U/g wet cell and E value of 24.1 ± 1.2. The specific activity of the purified PvEH3E134K/T137P (14.5 ± 0.5 U/mg protein) towards rac-3a and its catalytic efficiency (kcat/Km of 5.67 mM−1 s−1) for (S)-3a were 1.7- and 3.54-fold those (8.4 ± 0.3 U/mg and 1.60 mM−1 s−1) of PvEH3. The gram-scale kinetic resolution of rac-3a using whole wet cells of E. coli/pveh3E134K/T137P was performed at 20 °C for 7.0 h, producing (R)-3a with 99.4% ees and 38.5 ± 1.2% yield. Additionally, the mechanism of PvEH3E134K/T137P with remarkably improved E value was analyzed by molecular docking simulation.
Visualization of aquaionic splitting via iron corrosion
Authors: Murakami Shuntaro , Zhang Lihua , Watanabe Seiichi
Published: February 2020

We report a water decomposition mode called ‘Aquaionic Splitting (AiS)’ by means of iron corrosion in aqueous solution. In this paper, we investigated the phenomenon by controlling the reaction between iron and water. A pseudo-sacrificial protection method with oil paint was employed to select the anode and cathode formation locations that govern iron corrosion. Then, the AiS reaction was visualized by using BTB solution, whose colour corresponds to pH, to produce colour patterning that corresponds to the aquaion distribution. It has become clear that water can be selectively separated into protons and hydroxide ions by corrosion control treatment. In this vein, the diffusion coefficient of protons was estimated by using the colour patterning of BTB solution that accompanies iron corrosion, and aquaion distribution was then computer simulated by solving the diffusion equation.
Damage accumulation mechanism in PIN diode limiters induced via multiple microwave pulses
Authors: Zhao Jingtao , Chen Quanyou , Zhao Gang , Chen Chaoyang , Chen Zhidong
Published: February 2020

Positive-intrinsic-negative (PIN) diodes are widely used as limiters to protect sensitive components from damage in radio frequency (RF) receiver systems and communication front-ends. However, PIN diode limiters can be burnt out due to the microwave pulses coupling through the front-end of RF receiver systems. The damage processes and mechanisms in PIN limiters are undoubtedly important topics. Here, the damage accumulation process in PIN limiters induced by external microwave pulses is studied via the injection experiments. The relationship between the degree of damage (i.e., insertion loss) in the limiters and number of the injected pulses is reported. The maximum temperature criterion for burnout in PIN limiters is theoretically predicted and experimentally verified not accurate, and it is further observed that the insertion loss of the PIN diode limiter changes significantly only if more energy is injected into the limiter via microwave pulses.
Impact of concurrent right ventricular myocardial infarction on outcomes among patients with left ventricular myocardial infarction
Authors: Liao Huocheng , Chen Qiuyue , Liu Lin , Zhong Sigan , Deng Huazhao , Xiao Chun
Published: February 2020

To compare in-hospital outcomes between left ventricular myocardial infarction (LVMI) patients with and without right ventricular myocardial infarction (RVMI). Patients with acute ST-segment elevation MI (STEMI) undergoing primary percutaneous coronary intervention (PCI) were enrolled and divided into LVMI with and without RVMI groups. Between-group differences and in-hospital outcomes were compared. Compared to patients without RVMI, patients with RVMI were more likely to be male, have higher body mass index, serum levels of C-reactive protein (8.9 ± 2.4 vs 6.2 ± 2.1 mg/dL), B-type natriuretic peptide (1295 ± 340 vs 872 ± 166 pg/mL) and cardiac troponin-I (8.6 ± 2.9 vs 5.2 ± 2.1 ng/mL), and have diabetes (36.3% vs 3.4%) and dyslipidemia (53.4% vs 48.1%). Patients with RVMI had lower left and right ventricular ejection fraction (50.5 ± 5.6% vs 53.4 ± 3.8% and 33.6 ± 2.9% vs 45.7 ± 2.0%), but had higher mean pulmonary artery pressure (30.6 ± 3.3 vs 23.8 ± 3.1 mm Hg). Compared to patients without RVMI, patients with RVMI had higher odds of in-hospital all-cause mortality (4.1% vs 1.0%) and new onset acute heart failure (3.4% vs 1.0%). After adjusted for confounding factors, LVMI with RVMI remained independently associated with composite outcomes, with odds ratio 1.66 (95% confidence interval 1.39–2.04). Compared to isolated LVMI patients, those with concomitant RVMI have higher odds of in-hospital complications, particularly all-cause mortality and new onset acute heart failure.
Mutation type classification and pathogenicity assignment of sixteen missense variants located in the EGF-precursor homology domain of the LDLR
Authors: Galicia-Garcia Unai , Benito-Vicente Asier , Uribe Kepa B. , Jebari Shifa , Larrea-Sebal Asier , Alonso-Estrada Rocio , Aguilo-Arce Joseba , Ostolaza Helena , Palacios Lourdes , Martin Cesar
Published: February 2020

The primary genetic cause of familial hypercholesterolemia (FH) is related to mutations in the LDLR gene encoding the Low-density Lipoprotein Receptor. LDLR structure is organized in 5 different domains, including an EGF-precursor homology domain that plays a pivotal role in lipoprotein release and receptor recycling. Mutations in this domain constitute 51.7% of the total missense variants described in LDLR. The aim of the present work was to analyse how clinically significant variants in the EGF-precursor homology domain impact LDLR. The activity of sixteen LDLR variants was functionally characterized by determining LDLR expression by Western blot and LDLR expression, LDL binding capacity and uptake, and LDLR recycling activity by flow cytometry in transfected CHO-ldlA7 cells. Of the analysed variants, we found six non-pathogenic LDLR variants and ten pathogenic variants distributed as follow: three class 3 variants; four class 2 variants; and three class 5 variants. These results can be incorporated into clinical management of patients by helping guide the appropriate level of treatment intensity depending on the extent of loss of LDLR activity. This data can also contribute to cascade-screening for pathogenic FH variants.
CoCrMo surface modifications affect biocompatibility, adhesion, and inflammation in human osteoblasts
Authors: Lohberger Birgit , Stuendl Nicole , Glaenzer Dietmar , Rinner Beate , Donohue Nicholas , Lichtenegger Helga C. , Ploszczanski Leon , Leithner Andreas
Published: February 2020

In this study, different surface modifications were performed on a Cobalt-Chrome-Molybdenum (CoCrMo) alloy and the effects on cell viability and cytotoxicity as well as the adhesion potential of human osteoblasts (hFOB) and their inflammation reaction were investigated in vitro. CoCrMo discs were coated with TiN, with polished and porous coated surfaces, or with pure titanum (cpTi) surfaces and examined by Scanning Electron Microscopy to evaluate surface modifications. In vitro cell viability, adhesion behaviour, and expression of inflammation markers of hFOB human osteoblasts were measured via CellTiter-Glo, CytoTox, ELISA, and RT-PCR respectively. All results were compared to CoCrMo without surface modifications. The biocompatibility data showed high compatibility for the TiN hard coatings. Likewise, the porous surface coating increased cell viability significantly, compared to an untreated CoCrMo alloy. None of the investigated materials influenced cytotoxicity. Different surface modifications did not influence expression of fibronectin, although TiN, porous surface coatings and polished surfaces showed highly significant reductions in integrin subunit expression. In addition to the regulation of adhesion potential these three surfaces stimulated an anti-inflammatory response by osteocytes. Improved biocompatibility and adhesion properties may contribute to better osteointegration of prosthetics.
Genetic recombination of poly(l-lysine) functionalized apoferritin nanocages that resemble viral capsid nanometer-sized platforms for gene therapy
Authors: Huang Haiqin , Yuan Shirui , Ma Zhuo , Ji Peng , Ma Xiaonan , Wu Zhenghong , Qi Xiaole
Published: February 2020

Currently, bioengineered apoferritin nanocages with flexible protein shells and functionalized modifications have become an attractive approach for efficient anti-tumor therapy.
Effects of alkali metal promoters on the structure–performance relationship of CoMn catalysts for Fischer–Tropsch synthesis
Authors: Li Zhengjia , Yao Nan , Cen Jie , Li Xiaonian , Zhong Liangshu , Sun Yuhan , He Mingyuan
Published: February 2020

Alkali metal promoters are beneficial for the formation and facet-stabilization of Co2C nanoprisms for the FTO reaction.
Seaweed bio-inspired ZnO piezoelectric cilia array applied in microreactors for enhanced photocatalytic performance
Authors: Chen Yukai , Fang Jiaojiao , Dai Baoying , Wei Huimin , Kou Jiahui , Lu Chunhua
Published: February 2020

A piezoelectric built-in electric field is believed to be an effective way to separate photoinduced carriers and enhance photocatalytic performance.
A nature-inspired protective coating on soft/wet biomaterials for SEM by aerobic oxidation of polyphenols
Authors: Park Hong Key , Lee Daiheon , Lee Haeshin , Hong Seonki
Published: February 2020

We introduce a nature-inspired coating for SEM imaging of hydrated soft biomaterials by aerobic oxidation of polyphenols.
Applications of nano-porous graphene materials – critical review on performance and challenges
Authors: Guirguis Albert , Maina James W. , Zhang Xiwang , Henderson Luke C. , Kong Lingxue , Shon Hokyong , Dumée Ludovic F.
Published: February 2020

A critical review on the potential of nano-porous graphene materials, their key structural and physicochemical properties for applications in the areas of separation and sensing and energy storage.
Synthesis of 3-acylindoles via copper-mediated oxidative decarbethoxylation of ethyl arylacetates
Authors: Jaiswal Anjali , Sharma Anup Kumar , Singh Krishna Nand
Published: February 2020

Copper-mediated oxidative decarboxylation of ethyl arylacetates has been accomplished in the presence of indoles to afford 3-acylindoles using DMSO as an oxidant.
Synthetic and mechanistic aspects of sulfonyl migrations
Authors: Flynn Aaran J. , Ford Alan , Maguire Anita R.
Published: February 2020

Sulfonyl migrations, frequently described as ‘unusual’ or ‘unexpected’, from the last 20 years, including 1,2-, 1,3-, 1,4-, 1,5-, 1,6- and 1,7-sulfonyl shifts, through either radical or polar processes, either inter- or intramolecularly are reviewed.
A two-dimensional bilayered Dion–Jacobson-type perovskite hybrid with a narrow bandgap for broadband photodetection
Authors: Fu Dongying , Yuan Jianrong , Wu Shichao , Yao Yunpeng , Zhang Xinyuan , Zhang Xian-Ming
Published: February 2020

A unique 2D bilayered Dion–Jacobson type perovskite hybrid semiconductor shows broadband photodetection.
Hollow core/shell β-Bi2O3@WS2 p–n heterojunction for efficient photocatalytic degradation of fluoroquinolones: a theoretical and experimental study
Authors: Li Li , Yan Yunhui , Liu Haiping , Du Jinge , Fu Shuai , Zhao Fengying , Xu Si-Min , Zhou Jianguo
Published: February 2020

An efficient visible-light-driven β-Bi2O3@WS2 p–n core–shell heterostructure was rationally designed using theoretical calculations and then fabricated via a facile self-assembly method.
Phase I metabolic profiling and unexpected reactive metabolites in human liver microsome incubations of X-376 using LC-MS/MS: bioactivation pathway elucidation andin silicotoxicity studies of its metabolites
Authors: Attwa Mohamed W. , Kadi Adnan A. , Abdelhameed Ali S.
Published: February 2020

Metabolites ofX-376were characterized by LC-MS/MS. Pyridazine ring and dichloro-phenyl groups were bioactivated by novel pathways.
QSAR modeling of the toxicity classification of superparamagnetic iron oxide nanoparticles (SPIONs) in stem-cell monitoring applications: an integrated study from data curation to model development
Authors: Kotzabasaki Marianna I. , Sotiropoulos Iason , Sarimveis Haralambos
Published: February 2020

Development of a novel QSAR model for the prediction of toxicity of superparamagnetic iron oxide nanoparticles (SPIONs) in stem-cell monitoring applications.
The synergistic effect of the PEO–PVA–PESf composite polymer electrolyte for all-solid-state lithium-ion batteries
Authors: Xu Ling , Wei Kaiyuan , Cao Yong , Ma Shiping , Li Jian , Zhao Yu , Cui Yixiu , Cui Yanhua
Published: February 2020

PVA and PESf have synergistic effects for CPE, resulting in a wider electrochemical window, higher ionic conductivity and better cyclic performance.
Superhydrophobic lotus-leaf-like surface made from reduced graphene oxide through soft-lithographic duplication
Authors: Yun Xiawei , Xiong Zhiyuan , He Yaning , Wang Xiaogong
Published: February 2020

In this work, reduced graphene oxide was used as a material to fabricate a superhydrophobic lotus-leaf-like surface through soft-lithographic duplication.
Physical chemistry students’ navigation and use of models to predict and explain molecular vibration and rotation
Authors: Beck Jordan P. , Muniz Marc N. , Crickmore Cassidy , Sizemore Logan
Published: February 2020

Models that are used to predict and explain phenomena related to molecular vibration and rotation are ubiquitous in physical chemistry, and are of importance in many related fields. Yet, little work has been done to characterize student use and application of these models. We describe the results of a multi-year, multi-institutional qualitative study to investigate how students work with and apply models of molecular vibration and rotation. Our findings indicate that a sizable fraction of students (1) struggle to interpret the meaning of wavefunctions, (2) do not appropriately build potential and kinetic energy terms into models, and (3) conflate portions of various model systems. The data suggests that the ordering of content in the quantum chemistry course impacts students’ ideas about the rotational and vibrational behavior of molecules. The results are analyzed through the lenses of a two theoretical frameworks: one for scientific modeling, and one for heuristics in the context of chemistry. Implications for research and teaching practice are provided.
Adaptable Eu-containing polymeric films with dynamic control of mechanical properties in response to moisture
Authors: Wei Zichao , Thanneeru Srinivas , Margaret Rodriguez Elena , Weng Gengsheng , He Jie
Published: February 2020

Moisture that competes with dipicolylamine to bind Eu dynamically controls the mechanical and optical properties of polymer films, as well as their self-healing efficiency.
Bandgap bowing in a zero-dimensional hybrid halide perovskite derivative: spin–orbit coupling versus lattice strain
Authors: Chatterjee Soumyo , Payne Julia , Irvine John T. S. , Pal Amlan J.
Published: February 2020

The bandgap bowing phenomenon has been observed in lead-free MA3Sb2I9 perovskite upon isovalent substitution by bismuth (Bi3+).
Artificial nitrogen fixation over bismuth-based photocatalysts: fundamentals and future perspectives
Authors: Huang Yewei , Zhang Nan , Wu Zhenjun , Xie Xiuqiang
Published: February 2020

Fundamentals and future perspectives on artificial N2 fixation over bismuth-based photocatalysts have been discussed.
A dehydrobenzoannulene-based three dimensional graphdiyne for photocatalytic hydrogen generation using Pt nanoparticles as a co-catalyst and triethanolamine as a sacrificial electron donor
Authors: Shen Han , Zhou Weixiang , He Feng , Gu Yanan , Li Yongjun , Li Yuliang
Published: February 2020

A helical fiber-like structure from a three dimensional arrangement of an alkyne exhibits good ability for photocatalytic hydrogen generation using a Pt co-catalyst.
Facile synthesis of covalent organic framework derived Fe-COFs composites as a peroxidase-mimicking artificial enzyme
Authors: Zhou Liya , Luo Xucong , Gao Jing , Liu Guanhua , Ma Li , He Ying , Huang Zhihong , Jiang Yanjun
Published: February 2020

An artificial catalyst (Fe-COFs) with peroxidase-like activity was successfully synthesized at room temperature and applied to catalyze the reaction between TMB and H2O2.
Metal–organic frameworks: opportunities and challenges for surface-enhanced Raman scattering – a review
Authors: Lai Huasheng , Li Gongke , Xu Fugang , Zhang Zhuomin
Published: February 2020

MOF-based substrates and their SERS applications.
Resource allocation in power domain NOMA‐based cooperative multicell networks
Authors: Nazari Ali , Javan Mohammad Reza , Hosseini Shima Salar
Published: February 2020

In this paper, we propose a novel resource allocation scheme for non‐orthogonal multiple access (NOMA) based cooperative cellular networks where in each cell, two pairs of transmitter–receiver want to communicate via the base station (BS) which serves as a decode‐and‐forward (DF) relay. In the first hop, the transmitters simultaneously transmit their information and the BS applies joint decoding method. The BS transmits the received information towards the receivers based on NOMA technique. The receivers apply the successive interference cancellation (SIC) where the SIC ordering of receivers is determined based on the direct channel gain. We formulate the resource allocation problem as an optimization problem which is non‐convex. To tackle the non‐convexity, we adopt the successive convex approximation (SCA) with difference of two concave functions (D.C.) as the approximation technique. We also study the computational complexity of our proposed scheme. Finally, we study the performance of our scheme by simulations and compare it with existing transmission schemes like the orthogonal frequency multiple access (OFDMA) and the case where both of the first hop and the second hop adopt PD‐NOMA as well as the case where a special sort of subcarrier pairing is performed between the first and second hops.
Air‐to‐ground channel model for UAVs in dense urban environments
Authors: Safwat Nour El‐Din , Newagy Fatma , Hafez Ismail M.
Published: February 2020

A new analytical model of air‐to‐ground (A2G) channel between a low altitude unmanned aerial vehicle (UAV) and a mobile station is derived. It is proposed for the dense urban environment at frequencies of (1, 2 and 5.8) GHz. The model terms are determined on the basis of ray‐tracing simulation analysis for A2G channel and knife‐edge diffraction theory. The model is compared with the other A2G model and shows better results of standard error and confidence interval validation. Furthermore, the effects of changing the frequency and UAV height on path loss and probability of line of sight are discussed. Therefore, the proposed model provides a simple and good estimation compared to the complicity of ray‐tracing simulation.
E-Zigaretten – Funktionsweise, Inhaltsstoffe und die Vaping-assoziierte akute Lungenschädigung
Authors: Schupp J. C. , Prasse A. , Erythropel H. C.
Published: February 2020

Seit April 2019 kam es in den USA zu über 2000 Erkrankungen, bei denen zumeist junge Patienten mit schweren Lungenschädigungen in Krankenhäuser eingewiesen wurden. Im Verlauf sind bisher mehr als 40 Patienten verstorben. Nur ein einziger Zusammenhang konnte zwischen diesen Patienten ermittelt werden: Sie waren alle Nutzer von elektronischen Zigaretten (E-Zigaretten). Mittlerweile wird das Krankheitsbild im Englischen als EVALI bezeichnet (engl. „e-cigarette, or vaping, product use associated lung injury”, E-Zigaretten- oder Vaping-assoziierte Lungenschädigung). Basierend auf zumeist US-amerikanischen Studien zum Thema soll diese Übersichtsarbeit einen Einblick in die Definition, die Epidemiologie, das Krankheitsbild, den typischen Verlauf und potenzielle Auslöser, wie z. B. Vitamin-E-Acetat, von EVALI geben. Zusätzlich soll ein allgemeiner Überblick über die prinzipielle Funktionsweise von E-Zigaretten, die Inhaltsstoffe der verdampften Flüssigkeiten (E-Liquids) sowie die damit verbundenen Inhalationsrisiken gegeben werden.
Ketamine Infusion for Super Refractory Status Epilepticus in Alternating Hemiplegia of Childhood
Authors: Samanta Debopam
Published: February 2020

Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disorder and characterized by infantile onset hemiplegia involving either side of the body and other paroxysmal spells, including epilepsy. The N-methyl-D-aspartate (NMDA) receptor noncompetitive antagonist ketamine has been proved to be effective terminating status epilepticus (SE) in animal models and human case studies. Less than 50 cases, those use ketamine, have been reported in the management of pediatric SE, but its effectiveness is unknown in patients with AHC. The author reported two patients with molecularly confirmed AHC who presented with super refractory status epilepticus. These two patients failed multiple antiepileptic drugs, including midazolam infusion and propofol but responded promptly to ketamine infusion. This is the first description of the effectiveness of ketamine as an effective third-line agent for super refractory SE associated with AHC. Increased glutamate-mediated neurotoxicity can be present in AHC, not only due to overexpression of glutamate receptors during status epilepticus but also due to unique characteristics of AHC-preferential inactivity of GABAergic interneuron and impaired action of glutamate transporters (EAAT-1). Moreover, as neuroregression is possible after SE in AHC, earlier termination of SE by using ketamine can be an effective option in this population. Further prospective, controlled studies are needed to confirm the finding of this study.
A formula to calculate solid dielectric breakdown strength based on a model of electron impact ionization and multiplication
Authors: Zhao Liang
Published: February 2020

A formula to calculate the electrical breakdown strength EBD of solid dielectrics is derived based on a model of electron impact ionization and multiplication. This formula takes into account three types of parameters that influence EBD, namely, dielectric parameters (dielectric temperature and atom density), impact ionization parameters (ionization energy and probability), and multiplication parameters (number of initial electrons and number of generations of secondary electrons). The predictions of this formula are found to agree with experimental results. In addition, comparisons are made between the results of this formula and those of 38-generation-electron theory and other models, which show that the proposed formula is most appropriate to describe the breakdown of solid dielectrics on a nanosecond time scale.
Effect of transverse beam size on the wakefields and driver beam dynamics in plasma wakefield acceleration schemes
Authors: Bera Ratan Kumar , Mandal Devshree , Das Amita , Sengupta Sudip
Published: February 2020

In this paper, wakefields driven by a relativistic electron beam in a cold homogeneous plasma are studied using 2D fluid simulation techniques. It has been shown that in the limit when the transverse size of a rigid beam is greater than the longitudinal extension, the wake wave acquires a purely electrostatic form, and the simulation results show a good agreement with the 1D results given by Bera et al. [Phys. Plasmas 22, 073109 (2015)]. In the other limit when the transverse dimensions are equal to or smaller than the longitudinal extension, the wake waves are electromagnetic in nature, and 2D effects play a crucial role. Furthermore, a linear theoretical analysis of 2D wakefields for a rigid bi-parabolic beam has also been carried out and compared with the simulations. It has also been shown that the transformer ratio, which is a key parameter that measures the efficiency in the process of acceleration, becomes higher for a 2D system (i.e., for a beam having a smaller transverse extension compared to the longitudinal length) than the 1D system (i.e., for a beam having a larger transverse extension compared to the longitudinal length). Furthermore, including the self-consistent evolution of the driver beam in the simulation, we have seen that the beam propagating inside the plasma undergoes transverse pinching, which occurs much earlier than the longitudinal modification. Due to the presence of transverse dimensions in the system, the 1D rigidity limit given by Tsiklauri [Phys. Plasmas 25, 032114 (2018)] gets modified. We have also demonstrated the modified rigidity limit for the driver beam in a 2D beam–plasma system.
Enhancement-limit of Smith–Purcell radiation with self-bunched keV-order electron beam
Authors: Annaka Y. , Ogura K. , Sato Y. , Nakasone M. , Rachi K. , Takahashi T. , Hoshi Y.
Published: February 2020

We studied enhanced Smith–Purcell (SP) radiation produced by a self-bunched keV-order electron beam based on a W-band surface-wave oscillator. The self-bunched beam is generated in the process of the beam interaction with the surface-wave mode. The bunched beam contains the second harmonic of the surface wave that enhances the SP radiation. The observed radiation shows that the enhancement is limited when the interaction transitions from the Compton regime to the Raman regime.
Helical Bragg gratings filter for orbital angular momentum wave
Authors: Ober Seamus , Liu Xiaoli , Crouse David , Tan Chee-Keong
Published: February 2020

Effective filtration of orbital angular momentum (OAM) modes is essential to achieve multiple-channel data transmission in an OAM fiber for telecommunication applications. The nature of helical-shaped OAM wave propagation possessing many topological charges implies the need for uniquely designed index-modulated filters to conform to its twisted propagating direction in the fiber. Here, different from previous structures in demultiplexing OAM modes, a helical-shaped fiber grating structure concept is proposed as a pathway toward efficient demultiplexing of OAM modes in a fiber. A comparison of our proposed structure with the conventional fiber Bragg filter in transmitting an OAM wave shows a stronger reflection of the higher order OAM mode. We suggest that the proposed fiber Bragg structure has strong potential to be used for OAM fiber telecommunication technology.
Azetidinium as cation in lead mixed halide perovskite nanocrystals of optoelectronic quality
Authors: Kesava Sameer Vajjala , Hassan Yasser , Privitera Alberto , Varambhia Aakash , Snaith Henry J. , Riede Moritz K.
Published: February 2020

Previous theoretical calculations show that azetidinium has the right radial size to form a 3D perovskite with lead halides [G. Kieslich et al., Chem. Sci. 5, 4712 (2014)] and has been shown to impart, as the A-site cation of the ABX3 unit, beneficial properties to ferroelectric perovskites [B. Zhou et al., Angew. Chem., Int. Ed. 50, 11441 (2011)]. However, there has been very limited research into its use as the cation in lead halide perovskites to date. In this communication, we report the synthesis and characterization of azetidinium-based lead mixed halide perovskite colloidal nanocrystals. The mixed halide system is iodine and chlorine unlike other reported nanocrystals in the literature, where the halide systems are either iodine/bromine or bromine/chlorine. UV-visible absorbance data, complemented with photoluminescence spectroscopy, reveal an indirect-bandgap of about 2.018 eV for our nanocrystals. Structural characterization using transmission electron microscopy shows two distinct interatomic distances (2.98 Å ± 0.15 Å and 3.43 Å ± 0.16 Å) and non-orthogonal lattice angles (≈112°) intrinsic to the nanocrystals with a probable triclinic structure revealed by X-ray diffraction. The presence of chlorine and iodine within the nanocrystals is confirmed by energy dispersive X-ray spectroscopy. Finally, light-induced electron paramagnetic resonance spectroscopy with PCBM confirms the photoinduced charge transfer capabilities of the nanocrystals. The formation of such semiconducting lead mixed halide perovskites using azetidinium as the cation suggests a promising subclass of hybrid perovskites holding potential for optoelectronic applications such as in solar cells and photodetectors.
Stretchable and durable Parylene/PEDOT:PSS/Parylene multi-layer induced by plastic deformation for stretchable device using functionalized PDMS
Authors: Takei Atsushi , Tsukamoto Shiho , Komazaki Yusuke , Kusaka Yasuyuki , Kuribara Kazunori , Yoshida Manabu
Published: February 2020

Currently, electronic components having wavy structures are being actively studied because such wavy structures exhibit stretchability through flattening under stretching. The buckling of a thin film on an elastomer is an easy and inexpensive approach of creating a wavy structure and has attracted considerable attention. Despite its simplicity and easiness, the requirement of stretchers during film deposition limits fabrication methods, such as spin-coating and printing methods, and hinders their application in industry. Here, we eliminated the requirement of stretchers during film deposition by utilizing plastic deformation of the thin film and extending methods of developing a wrinkle structure. We used poly-3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), the most widely used conductive polymer, as a thin film and adopted its stretchable wrinkle structure for stretchable electronic devices. The stretchability and durability of PEDOT:PSS were enhanced by sandwiching the PEDOT:PSS layer between two Parylene layers. The PEDOT:PSS layer was conductive at a stretch of up to 170%, and the change in resistance was less than 10% after 4000 cyclic loads. Additionally, we demonstrated a new concept of a flexible and stretchable light emitting device using the proposed Parylene/PEDOT:PSS/Parylene multi-layer and functionalized polydimethylsiloxane.
Magneto-optical properties of spin-coated bismuth-substituted yttrium iron garnet films on silicon substrates at 1550-nm wavelength
Authors: Kim Yudeuk , Bang David Juseong , Kim Yonghwan , Kim Kyong Hon
Published: February 2020

Bismuth-substituted yttrium iron garnet (Bi:YIG) films were prepared by using spin coating processes with metal-organic-decomposition-method-based solutions on crystalline silicon (Si) substrates, and their magneto-optic properties at the 1550-nm wavelength region were investigated by performing various thermal treatments. The maximum Verdet constant of the Bi1Y2Fe5O12 film on the Si substrate with a middle buffer layer of Bi2Y1 Fe5 O12 was measured to be 1 072 038°/T/m at 1550-nm wavelength in the unsaturated linear magnetization region by accounting for the negative Verdet constant of the silicon substrate. The optimum thermal treatment condition was observed at the maximum annealing temperature of 700 °C and the annealing speed of 3 °C/min. These spin coating enabled processes may be included to the conventional complementary metal-oxide semiconductor fabrication processes to demonstrate integrated optical waveguide-type isolators on silicon-on-insulator wafers.
Quasi-degenerate states and their dynamics in oxygen deficient reducible metal oxides
Authors: Daelman Nathan , Hegner Franziska Simone , Rellán-Piñeiro Marcos , Capdevila-Cortada Marçal , García-Muelas Rodrigo , López Núria
Published: February 2020

The physical and chemical properties of oxides are defined by the presence of oxygen vacancies. Experimentally, non-defective structures are almost impossible to achieve due to synthetic constraints. Therefore, it is crucial to account for vacancies when evaluating the characteristics of these materials. The electronic structure of oxygen-depleted oxides deeply differs from that of the native forms, in particular, of reducible metal oxides, where excess electrons can localize in various distinct positions. In this perspective, we present recent developments from our group describing the complexity of these defective materials that highlight the need for an accurate description of (i) intrinsic vacancies in polar terminations, (ii) multiple geometries and complex electronic structures with several states attainable at typical working conditions, and (iii) the associated dynamics for both vacancy diffusion and the coexistence of more than one electronic structure. All these aspects widen our current understanding of defects in oxides and need to be adequately introduced in emerging high-throughput screening methodologies.
Optical field tuning of localized plasmon modes in Ag microcrystals at the nanofemto scale
Authors: Dai Yanan , Dąbrowski Maciej , Petek Hrvoje
Published: February 2020

Nanoscale plasmonic field enhancement at sub-wavelength metallic particles is crucial for surface sensitive spectroscopy, ultrafast microscopy, and nanoscale energy transduction. Here, we demonstrate control of the spatial distribution of localized surface plasmon modes at sub-optical-wavelength crystalline silver (Ag) micropyramids grown on a Si(001) surface. We employ multiphoton photoemission electron microscopy (mP-PEEM) to image how the plasmonic field distributions vary with the photon energy, light polarization, and phase in coherent two-pulse excitation. For photon energy hυ > 2.0 eV, the mP-PEEM images show single photoemission locus, which splits into a dipolar pattern that straddles the Ag crystal at a lower energy. We attribute the variation to the migration of plasmon resonances from the Ag/vacuum to the Ag/Si interfaces by choice of the photon energy. Furthermore, the dipolar response of the Ag/Si interface follows the polarization state of light: for linearly polarized excitations, the plasmon dipole follows the in-plane electric field vector, while for circularly polarized excitations, it tilts in the direction of the handedness due to the conversion of spin angular momentum of light into orbital angular momentum of the plasmons excited in the sample. Finally, we show the coherent control of the spatial plasmon distribution by exciting the sample with two identical circularly polarized light pulses with delay defined with attosecond precision. The near field distribution wobbles at the pyramid base as the pump–probe delay is advanced due to interferences among the contributing fields. We illustrate how the frequency, polarization, and pulse structure can be used to design and control plasmon fields on the nanofemto scale for applications in chemistry and physics.
Dynamic osmosis is demonstrated as an alternative water filtration system
Authors: Mandel Savannah
Published: February 2020

Harnessing dynamic osmosis through active membranes might lead to a new category of water filtration devices.
The Time Local Convex Hull method as a tool for assessing responses of fauna to habitat restoration: a case study using the perentie (Varanus giganteus : Reptilia : Varanidae)
Authors: Cross Sophie L. , Tomlinson Sean , Craig Michael D. , Bateman Philip W.
Published: February 2020

Understanding the behavioural responses of animals to habitat change is vital to their conservation in landscapes undergoing restoration. Studies of animal responses to habitat restoration typically assess species presence/absence; however, such studies may be restricted in their ability to show whether restoration is facilitating the return of self-sustaining and functional fauna populations. We present a case study using VHF/GPS tracking of a young adult perentie (Varanus giganteus), to demonstrate the range of applications of the Time Local Convex Hull method of home-range construction in analysing the behavioural responses of fauna to habitat change and restoration. Presence/absence studies provide single point locations of an animal, and the Minimum Convex Polygon method provides an invariant estimate of habitat use across the whole home range. However, the Time Local Convex Hull method provides a useful method for assessing movement and behavioural responses of fauna to habitat change and restoration, and the specific habitat requirements for the long-term support of populations. The breadth and multidimensionality of data generated indicates strongly that understanding the complex interactions between animals and their environment is fundamental to their conservation in the face of ever-increasing rates of human-induced habitat change and degradation.
Race, Slavery and Domesticity in Late Qajar
Chronicles
Authors: DeSouza Wendy
Published: February 2020

This article examines cultural attitudes
on race and African slavery in late Qajar
chronicles prior to abolition in 1929. In contrast
to previous scholarship, Qajar textual sources
reveal that elite cultural attitudes were relevant
in structuring the social conditions of
enslavement in Iran. Visual depictions and
narratives about African eunuchs and concubines
naturalized the violent acquisition and use of the
Other. Slave narratives also bear witness to how
such views of African corporeality determined the
social worth of eunuchs and concubines in the
domestic sphere.
Tailoring the morphology through alkali treatment: Dynamics of pattern formation
Authors: Saritha Devi H. V. , Swapna M. S. , Sankararaman S.
Published: February 2020

Diversified technological applications necessitate the tailoring of morphology of materials at nanoscale. This paper reports morphological modifications of boron carbide (BC) at nanoscale through alkali (NaOH) treatment. The multilayered hollow microspheres of BC, obtained by the refluxion of castor oil with boric acid, are subjected to exfoliation by sonicating it in the ethanol–water mixture. The attractive morphologies evolved in the sonication process as a result of changing the BC concentration, auxiliary agent and sonication time are analysed. The multilayered hollow structure on sonication with NaOH yields flower-like morphology that seems to evolve from the basic spindle structure. The morphological tuning makes the study relevant in the areas like bleaching, where the surface area is crucial.
Psychometric Properties of the MacArthur Community Violence Screening Instrument
Authors: Cartwright Joel K. , Desmarais Sarah L. , Grimm Kevin J. , Meade Adam W. , Van Dorn Richard A.
Published: February 2020

This study examined the psychometric properties of the MacArthur Community Violence Screening Instrument (MCVSI) in a heterogeneous and integrated sample of adults with mental illness ( n = 4,480), including its factor structure, model fit, and psychometric properties as a function of patient sex, race, and primary diagnosis. Factor structure results indicate a unidimensional construct. Item-level analyses revealed that the MCVSI’s difficulty, including the easiest and most difficult items to endorse, sometimes differed across sex, race, and primary diagnosis. However, differential item functioning was minimal across these patient characteristics, with only those without a primary diagnosis of schizophrenia indicating an increased likelihood of having “hit anyone with a fist, object or beaten anyone” compared to those with a primary diagnosis of schizophrenia. Overall, these findings support using the MCVSI as a measure of violence in studies of U.S. adults with mental illness. They also highlight the importance of using more methodologically rigorous approaches to measuring violence, including the ongoing study of the MCVSI across samples and settings.
Exosomes derived from HeLa cells break down vascular integrity by triggering endoplasmic reticulum stress in endothelial cells
Authors: Lin Yinuo , Zhang Chi , Xiang Pingping , Shen Jian , Sun Weijian , Yu Hong
Published: February 2020

Exosomes play a critical role in intercellular communication since they contain signalling molecules and genetic materials. During tumorigenesis, tumour‐derived exosomes have been demonstrated to promote tumour angiogenesis and metastasis. However, how the exosomes facilitate tumour metastasis is not clear. Here we explored the effect of HeLa cell‐derived exosomes (ExoHeLa) on endothelial tight junctions (TJ) and the related mechanisms. After human umbilical vein endothelial cells (HUVEC) were treated with ExoHeLa, TJ proteins zonula occludens‐1 (ZO‐1) and Claudin‐5 in HUVEC were significantly reduced as compared with that treated with exosomes from human cervical epithelial cells, while mRNA levels of ZO‐1 and Claudin‐5 remained unchanged. Consequently, permeability of endothelial monolayer was increased after the treatment with ExoHeLa. Injection of ExoHeLa into mice also increased vascular permeability and tumour metastasis in vivo. Neither knocking down of Dicer nor use of inhibitors of microRNAs targeting at mRNAs of ZO‐1 and Claudin‐5 could block the inhibitory effect of ExoHeLa on ZO‐1 and Claudin‐5. The expression of genes involved in endoplasmic reticulum (ER) stress was significantly increased in HUVECs after treated with ExoHeLa. Inhibition of ER stress by knocking down protein kinase RNA‐like endoplasmic reticulum kinase prevented the down‐regulation of ZO‐1 and Claudin‐5 by ExoHeLa. Our study found that HeLa cell‐derived exosomes promote metastasis by triggering ER stress in endothelial cells and break down endothelial integrity. Such effect of exosomes is microRNA‐independent.
Music perception in adult patients with cochlear implant
Authors: Sorrentino Flavia , Gheller Flavia , Favaretto Niccolò , Franz Leonardo , Stocco Elisabetta , Brotto Davide , Bovo Roberto
Published: February 2020

The music perception and more specifically the appreciation of music is a common aspiration among cochlear implant (CI) adult users. In the majority of patients, only rhythm perception is reported to be similar to that of listeners with normal hearing. Melody and timbre recognition requires more spectral and temporal fine structure cues that are not well supported by the CI representation: for these reasons music appreciation represents actually a true challenge for adult CI users. This review will take into account the available recent literature about the perception of rhythm, melody and timbre in adult CI users. Furthermore, some hints about rehabilitation of CI users to the music perception and appreciation will be presented.
High-frequency spin transfer nano-oscillator based on the motion of skyrmions in an annular groove
Authors: Jin Chendong , Ma Yunxu , Song Chengkun , Xia Haiyan , Wang Jianing , Zhang Chunlei , Zeng Zhaozhuo , Wang Jianbo , Liu Qingfang
Published: February 2020

Magnetic skyrmion-based spin transfer nano-oscillators (STNOs) have been proposed as microwave signal generators and attracted enormous interest recently. However, the oscillation frequency of skyrmion-based STNOs is about 2 GHz, which is not so high for practical applications. In this paper, we create an annular groove in the surface of the free layer and put skyrmions in the annular groove. Due to the potential of the groove, skyrmions are confined to moving in the groove when driven by the spin-polarized currents. Through micromagnetic simulations, it is found that the frequency tunability of the STNO with the presence of the annular groove reaches to 15.63 GHz, which is more than 6 times higher than the case without the presence of the annular groove because of three reasons: the oscillation radius of skyrmions can be adjusted by the groove, the potential of the groove is larger than that of the edge and the groove can limit the diameter of skyrmions so that a larger number of skyrmions can be placed in the groove. Our results present the understanding of dynamic of skyrmions in an annular groove, which provides alternative possibilities for the design of skyrmion-based STNOs.