bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative evaluation of SARS-CoV-2 inactivation using a deep ultraviolet light-emitting diode
Authors: Minamikawa Takeo , Koma Takaaki , Suzuki Akihiro , Mizuno Takahiko , Nagamatsu Kentaro , Arimochi Hideki , Tsuchiya Koichiro , Matsuoka Kaoru , Yasui Takeshi , Yasutomo Koji , Nomaguchi Masako
Published: March 2021

Inactivation technology for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is certainly a critical measure to mitigate the spread of coronavirus disease 2019 (COVID-19). A deep ultraviolet light-emitting diode (DUV-LED) would be a promising candidate to inactivate SARS-CoV-2, based on the well-known antiviral effects of DUV on microorganisms and viruses. However, due to variations in the inactivation effects across different viruses, quantitative evaluations of the inactivation profile of SARS-CoV-2 by DUV-LED irradiation need to be performed. In the present study, we quantify the irradiation dose of DUV-LED necessary to inactivate SARS-CoV-2. For this purpose, we determined the culture media suitable for the irradiation of SARS-CoV-2 and optimized the irradiation apparatus using commercially available DUV-LEDs that operate at a center wavelength of 265, 280, or 300 nm. Under these conditions, we successfully analyzed the relationship between SARS-CoV-2 infectivity and the irradiation dose of the DUV-LEDs at each wavelength without irrelevant biological effects. In conclusion, total doses of 1.8 mJ/cm2 for 265 nm, 3.0 mJ/cm2 for 280 nm, and 23 mJ/cm2 for 300 nm are required to inactivate 99.9% of SARS-CoV-2. Our results provide quantitative antiviral effects of DUV irradiation on SARS-CoV-2, serving as basic knowledge of inactivation technologies against SARS-CoV-2.
Resequencing and SNP discovery of Amur ide (Leuciscus waleckii) provides insights into local adaptations to extreme environments
Authors: Wang Shuangyi , Kuang Youyi , Liang Liqun , Sun Bo , Zhao Xuefei , Zhang Limin , Chang Yumei
Published: March 2021

Amur ide (Leuciscus waleckii), a Cyprinid species, is broadly distributed in Northeast Asia. Different from its freshwater counterparts, the population in Lake Dali Nor has a strong alkalinity tolerance and can adapt to extremely alkali–saline water with bicarbonate over 50 mmol/L. To uncover the genetic basis of its alkaline adaptation, three populations, including one alkali form from Lake Dali Nor (DL), one freshwater form from its adjacent sister Lake Ganggeng Nor (GG), and one freshwater form from its historical origin, namely, the Songhua River (SH), were analyzed using genome resequencing technology. A total of 679.82 Gb clean data and 38,091,163 high-quality single-nucleotide polymorphism (SNP) loci were detected in the three populations. Nucleotide diversity and population structure analysis revealed that the DL and GG populations have lower nucleotide diversities and different genetic structures than those of the SH population. Selective sweeping showed 21 genes involved in osmoregulatory regulation (DLG1, VIPR1, AKT1, and GNAI1), inflammation and immune responses (DLG1, BRINP1, CTSL, TRAF6, AKT1, STAT3, GNAI1, SEC22b, and PSME4b), and cardiorespiratory development (TRAF6, PSME4b, STAT3, AKT1, and COL9A1) to be associated with alkaline adaption of the DL population. Interestingly, selective pressure (CodeML, MEME, and FEL) methods identified two functional codon sites of VIPR1 to be under positive selection in the DL population. The subsequent 3D protein modeling confirmed that these selected sites will incur changes in protein structure and function in the DL population. In brief, this study provides molecular evidence of population divergence and alkaline adaptation, which will be very useful for revealing the genetic basis of alkaline adaptation in Amur ide.
Covalent grafting of molecular photosensitizer and catalyst on MOF-808: effect of pore confinement toward visible light-driven CO2 reduction in water
Authors: Karmakar Sanchita , Barman Soumitra , Rahimi Faruk Ahamed , Maji Tapas Kumar
Published: March 2021

We have fabricated Zr-MBA-Ru/Re-MOFvia post-synthetic modification of MOF-808. The integrated catalyst assembly was used to mimic natural photosynthesis for sunlight-driven CO2 reduction to produce CO in aqueous medium without external sacrificial electron donor.
Synthesis, properties and structural features of molybdenum(v) oxide trichloride complexes with neutral chalcogenoether ligands
Authors: Smith Danielle E. , Levason William , Powell James , Reid Gillian
Published: March 2021

The synthesis and properties of a systematic series of oxotrichloromolybdenum(v) complexes bearing neutral thio-, seleno- and telluroether ligands are described, together with their spectroscopic and structural studies.
Effects of Mouthpiece Noninvasive Ventilation on Speech in Men With Muscular Dystrophy: A Pilot Study
Authors: Britton Deanna , Pullen Elizabeth , Hoit Jeannette D. , Benditt Joshua O.
Published: March 2021

Purpose

The use of noninvasive ventilation (NIV) is on the rise as an alternative to tracheostomy for individuals with neuromuscular disorders with life-prolonging and quality-of-life benefits. This pilot study was designed to determine if mouthpiece NIV (M-NIV) alters speech in individuals with muscular dystrophy (MD).

Method

Eight men (23–44 years), seven with Duchenne MD and one with Becker MD, who used daytime M-NIV, were asked to sustain phonation, count, and read under three conditions: (a)
Uncued
(no instructions), (b)
With M-NIV
(cued to use M-NIV with all speaking breaths), and (c)
Without M-NIV
(as tolerated). Breath group and inspiratory durations, syllables/breath group, and relative sound pressure level were determined from audio and video recordings.

Results

Uncued condition: Participants used the ventilator for all inspirations that preceded sustained phonation and counting. During reading, four participants used M-NIV for all inspirations, one never used it, and three used it for some (19%–41%) inspirations.

With- versus Without-M-NIV conditions: Breath group duration was significantly longer across all tasks, syllables per breath group were significantly greater during reading, and inspiratory pause duration during reading was significantly longer with M-NIV than without. Sound pressure level was significantly higher during the first second of sustained phonation with M-NIV (though not for counting and reading). Two participants were unable to complete the reading task audibly without using their M-NIV.

Conclusions

Speech may be better with M-NIV than without because it is possible to produce longer breath groups and some people with severe respiratory muscle weakness may not be able to speak at all without ventilator-supplied air. Nevertheless, the longer inspiratory pauses that accompany M-NIV may interrupt the flow of speech. Future research is needed to determine the most effective way to use M-NIV for speaking and whether training participants in its use can bring even greater speech benefits.
Noise reduction in switched reluctance motor by modifying the structures
Authors: Hosseini Simin , Alinejad‐Beromi Yousef
Published: March 2021

The magnetic effects and consequently the radial force are the main causes of noise in switched reluctance motors (SRMs). In this study a new design for SRM is developed in order to reduce acoustic noise. In this research a new design for SRM is developed in order to reduce the acoustic noise. In this investigation, at first, different SRM structures are simulated using JMAG software. An 8/6‐pole SRM is designed and built with special modification in the rotor and stator structures. For increasing mechanical strength, trapezoidal stator and rotor pole shape with poles arc βr = βs = 21° are proposed. In this design the taper angles of stator and rotor poles are equal. For noise reduction, the mechanical restructuring is done according to stress analysis. The new designed SRM are simulated and tested experimentally under no‐load and full‐load conditions. The results are shown and compared. Comparison between these results and the results of other structures shows that the acoustic noise of the newly designed motor is reduced considerably. The results show an acoustic noise reduction of ∼72% in new structure SRM.
Photometric selection and redshifts for quasars in the Kilo-Degree Survey Data Release 4
Authors: Nakoneczny S. J. , Bilicki M. , Pollo A. , Asgari M. , Dvornik A. , Erben T. , Giblin B. , Heymans C. , Hildebrandt H. , Kannawadi A. , Kuijken K. , Napolitano N. R. , Valentijn E.
Published: March 2021

We present a catalog of quasars with their corresponding redshifts derived from the photometric Kilo-Degree Survey (KiDS) Data Release 4. We achieved it by training machine learning (ML) models, using optical ugri and near-infrared ZYJHKs bands, on objects known from Sloan Digital Sky Survey (SDSS) spectroscopy. We define inference subsets from the 45 million objects of the KiDS photometric data limited to 9-band detections, based on a feature space built from magnitudes and their combinations. We show that projections of the high-dimensional feature space on two dimensions can be successfully used, instead of the standard color-color plots, to investigate the photometric estimations, compare them with spectroscopic data, and efficiently support the process of building a catalog. The model selection and fine-tuning employs two subsets of objects: those randomly selected and the faintest ones, which allowed us to properly fit the bias versus variance trade-off. We tested three ML models: random forest (RF), XGBoost (XGB), and artificial neural network (ANN). We find that XGB is the most robust and straightforward model for classification, while ANN performs the best for combined classification and redshift. The ANN inference results are tested using number counts, Gaia parallaxes, and other quasar catalogs that are external to the training set. Based on these tests, we derived the minimum classification probability for quasar candidates which provides the best purity versus completeness trade-off: p(QSOcand) > 0.9 for r < 22 and p(QSOcand) > 0.98 for 22 < r < 23.5. We find 158 000 quasar candidates in the safe inference subset (r < 22) and an additional 185 000 candidates in the reliable extrapolation regime (22 < r < 23.5). Test-data purity equals 97% and completeness is 94%; the latter drops by 3% in the extrapolation to data fainter by one magnitude than the training set. The photometric redshifts were derived with ANN and modeled with Gaussian uncertainties. The test-data redshift error (mean and scatter) equals 0.009 ± 0.12 in the safe subset and −0.0004 ± 0.19 in the extrapolation, averaged over a redshift range of 0.14 < z < 3.63 (first and 99th percentiles). Our success of the extrapolation challenges the way that models are optimized and applied at the faint data end. The resulting catalog is ready for cosmology and active galactic nucleus (AGN) studies.
Aggregates of clusters in the Gaia data
Authors: Piecka M. , Paunzen E.
Published: March 2021

Context. The precision of the parallax measurements by Gaia is unprecedented. As of Gaia Data Release 2, the number of known nearby open clusters has increased. Some of the clusters appear to be relatively close to each other and form aggregates, which makes them interesting objects to study.

Aims. We study the aggregates of clusters which share several of the assigned member stars in relatively narrow volumes of the phase space.

Methods. Using the most recent list of open clusters, we compare the cited central parallaxes with the histograms of parallax distributions of cluster aggregates. The aggregates were chosen based on the member stars which are shared by multiple clusters.

Results. Many of the clusters in the aggregates have been assigned parallaxes which coincide with the histograms. However, clusters that share a large number of members in a small volume of the phase space display parallax distributions which do not coincide with the values from the literature. This is the result of ignoring a possibility of assigning multiple probabilities to a single star. We propose that this small number of clusters should be analysed anew.
Alkyl Halides as Substrates for Photocatalytic Minisci-Type C–H Alkylation of Hetarenes
Authors: Predygier Jędrzej , Szczepanik Joanna , Giedyk Maciej
Published: March 2021

Alkyl halides are readily available starting materials for various synthetic transformations, including Minisci-type C–H functionalizations of hetarenes. The existing methods, however, often require harsh reaction conditions, such as the use of acids, sacrificial electron donors, or radical precursors in excess amounts. Here, we outline recent developments in this field and we highlight our group̓s efforts to achieve fully catalytic photoredox Minisci-type alkylations supported by noncovalent interactions under mild aqueous conditions.
Outbreak of Enterovirus Infection with Neurological Presentations in a Pediatric Population in Northern Spain: A Clinical Observational Study
Authors: Hedrera-Fernandez Antonio , Cancho-Candela Ramon , Arribas-Arceredillo Marta , Garrido-Barbero Maria , Conejo-Moreno David , Sariego-Jamardo Andrea , Perez-Poyato Maria Socorro , Rodriguez-Fernandez Cristina , del Villar-Guerra Pablo , Bermejo-Arnedo Ignacio , Peña-Valenceja Alfonso , Maldonado-Ruiz Esther , Ortiz-Madinaveitia Saturnino , Camina-Gutierrez Ana Belen , Blanco-Lago Raquel , Malaga Ignacio
Published: March 2021

Objective The study aimed to describe the cases of neurological disease related to the outbreak of enterovirus (EV) in three regions in Northern Spain during 2016.

Materials and Methods Multicenter retrospective observational study. Clinical, radiological, and microbiological data were analyzed from patients younger than 15 years with confirmed EV-associated neurological disease admitted to 10 hospitals of Asturias, Cantabria, and Castile and Leon between January 1 and December 31, 2016.

Results Fifty-five patients were included. Median age was 24 months (interquartile range = 18.5 months). Fifteen patients were classified as aseptic meningitis (27.3%). In total, 37 cases presented brainstem encephalitis (67.3%), 25 of them due to EV-A71 with excellent prognosis (84.6% asymptomatic 2 months following the onset). Three cases of acute flaccid myelitis (5.5%) by EV-D68 were reported and presented persistent paresis 2 months following the onset. Microbiological diagnosis by reverse transcriptase polymerase chain reaction was performed in all cases, finding EV in cerebrospinal fluid in meningitis, but not in brainstem encephalitis and acute flaccid myelitis, where EV was found in respiratory or rectal samples. Step therapy was administrated with intravenous immunoglobulin (IVIG; 32.7%), methylprednisolone (10%), and plasmapheresis (3.6%). Four patients received fluoxetine (7.3%). Twenty patients needed to be admitted to pediatric intensive care unit (36.4%).

Conclusion Clinical, microbiological, and radiological diagnosis is essential in outbreaks of EV neurological disease, taking into account that it can be difficult to identify EV-A71 and EV-D68 in CSF, requiring throat or rectal samples. There is not specific treatment to these conditions and the efficacy and understanding of the mechanism of action of immune-modulatory treatment (IVIG, corticosteroids, and plasmapheresis) is limited.
Impact of the gas dynamics on the cluster flux in a magnetron cluster-source: Influence of the chamber shape and gas-inlet position
Authors: Sanzone Giuseppe , Yin Jinlong , Cooke Kevin , Sun Hailin , Lievens Peter
Published: March 2021

Although producing clusters by physical methods offers many benefits, low deposition rates have prevented cluster-beam deposition techniques from being adopted more widely. The influence of the gas aerodynamics inside the condensation chamber of a magnetron cluster-source on the cluster throughput is reported, leading to an improved understanding of the influence of gas aerodynamics on cluster transport. In the first part of this paper, the influence of the carrier gas’s inlet position on the cluster flux is studied. In particular, two inlet configurations were investigated, i.e., from the rear of the chamber and from within the magnetron sputtering source. It was found experimentally that the latter configuration can lead to an increased cluster flux, under the same conditions of gas pressure and power applied to the magnetron. This behavior is explained with the help of simulations. In the second part of this paper, the gas dynamics behavior inside four chamber shapes, namely, two cylindrical shapes with different cross-sectional diameters and two conical shapes with different apex angles, was simulated. The modeling showed that the fraction of clusters successfully leaving the aggregation zone can be increased by up to eight times from the worst to the best performing chamber geometries studied. Finally, the cluster throughput was determined experimentally using a quartz microbalance in two of the four chamber designs. It was found that the cluster flux increased up to one order of magnitude, reaching ∼20 mg/h for a condensation chamber with a smaller cross section and a conical exit.
Frequency shift algorithm: Application to a frequency-domain multiplexing readout of x-ray transition-edge sensor microcalorimeters
Authors: Vaccaro D. , Akamatsu H. , van der Kuur J. , van der Hulst P. , Nieuwenhuizen A. C. T. , van Winden P. , Gottardi L. , den Hartog R. , Bruijn M. P. , D’Andrea M. , Gao J. R. , den Herder J. W. A. , Hoogeveen R. W. M. , Jackson B. , van der Linden A. J. , Nagayoshi K. , Ravensberg K. , Ridder M. L. , Taralli E. , de Wit M.
Published: March 2021

In the frequency-domain multiplexing (FDM) scheme, transition-edge sensors (TESs) are individually coupled to superconducting LC filters and AC biased at MHz frequencies through a common readout line. To make efficient use of the available readout bandwidth and to minimize the effect of non-linearities, the LC resonators are usually designed to be on a regular grid. The lithographic processes, however, pose a limit on the accuracy of the effective filter resonance frequencies. Off-resonance bias carriers could be used to suppress the impact of intermodulation distortions, which, nonetheless, would significantly affect the effective bias circuit and the detector spectral performance. In this paper, we present a frequency shift algorithm (FSA) to allow off-resonance readout of TESs, while preserving the on-resonance bias circuit and spectral performance, demonstrating its application to the FDM readout of an x-ray TES microcalorimeter array. We discuss the benefits in terms of mitigation of the impact of intermodulation distortions at the cost of increased bias voltage and the scalability of the algorithm to multi-pixel FDM readout. We show that with FSA, in the multi-pixel and frequencies shifted on-grid, the line noises due to intermodulation distortion are placed away from the sensitive region in the TES response and the x-ray performance is consistent with the single-pixel, on-resonance level.
Dual responsiveness of microgels induced by single light stimulus
Authors: Bekir Marek , Jelken Joachim , Jung Se-Hyeong , Pich Andrij , Pacholski Claudia , Kopyshev Alexey , Santer Svetlana
Published: March 2021

We report on the multiple response of microgels triggered by a single optical stimulus. Under irradiation, the volume of the microgels is reversibly switched by more than 20 times. The irradiation initiates two different processes: photo-isomerization of the photo-sensitive surfactant, which forms a complex with the anionic microgel, rendering it photo-responsive; and local heating due to a thermo-plasmonic effect within the structured gold layer on which the microgel is deposited. The photo-responsivity is related to the reversible accommodation/release of the photo-sensitive surfactant depending on its photo-isomerization state, while the thermo-sensitivity is intrinsically built in. We show that under exposure to green light, the thermo-plasmonic effect generates a local hot spot in the gold layer, resulting in the shrinkage of the microgel. This process competes with the simultaneous photo-induced swelling. Depending on the position of the laser spot, the spatiotemporal control of reversible particle shrinking/swelling with a predefined extent on a per-second base can be implemented.
Utilizing complex oxide substrates to control carrier concentration in large-area monolayer MoS2 films
Authors: Zheng Xudong , Gerber Eli , Park Jisung , Werder Don , Kigner Orrin , Kim Eun-Ah , Xie Saien , Schlom Darrell G.
Published: March 2021

Bandgap engineering is central to the design of heterojunction devices. For heterojunctions involving monolayer-thick materials like MoS2, the carrier concentration of the atomically thin film can vary significantly depending on the amount of charge transfer between MoS2 and the substrate. This makes substrates with a range of charge neutrality levels—as is the case for complex oxide substrates—a powerful addition to electrostatic gating or chemical doping to control the doping of overlying MoS2 layers. We demonstrate this approach by growing monolayer MoS2 on perovskite (SrTiO3 and LaAlO3), spinel (MgAl2O4), and SiO2 substrates with multi-inch uniformity. The as-grown MoS2 films on these substrates exhibit a controlled, reproducible, and uniform carrier concentration ranging from (1–4) ×1013 cm−2, depending on the oxide substrate employed. The observed carrier concentrations are further confirmed by our density-functional theory calculations based on ab initio mismatched interface theory (MINT). This approach is relevant to large-scale heterostructures involving monolayer-thick materials in which it is desired to precisely control carrier concentrations for applications.
Connecting real glasses to mean-field models
Authors: Nandi Ujjwal Kumar , Kob Walter , Maitra Bhattacharyya Sarika
Published: March 2021

We propose a novel model for a glass-forming liquid, which allows us to switch in a continuous manner from a standard three-dimensional liquid to a fully connected mean-field model. This is achieved by introducing k additional particle–particle interactions, which thus augments the effective number of neighbors of each particle. Our computer simulations of this system show that the structure of the liquid does not change with the introduction of these pseudo-neighbors and by means of analytical calculations, and we determine the structural properties related to these additional neighbors. We show that the relaxation dynamics of the system slows down very quickly with the increase in k and that the onset and the mode-coupling temperatures increase. The systems with high values of k follow the mode-coupling theory power law behavior for a larger temperature range compared to the ones with lower values of k. The dynamic susceptibility indicates that the dynamic heterogeneity decreases with the increase in k, whereas the non-Gaussian parameter is independent of it. Thus, we conclude that with the increase in the number of pseudo-neighbors, the system becomes more mean-field-like. By comparing our results with previous studies on mean-field-like systems, we come to the conclusion that the details of how the mean-field limit is approached are important since they can lead to different dynamical behavior in this limit.
The joint probability density function of mixture fraction, reaction progress variable, and total enthalpy in a stratified, swirl-stabilized turbulent flame
Authors: Mousemi Arash , Kendal Bushe W.
Published: March 2021

The three-condition version of the uniform conditional state combustion model makes use of the mixture fraction, progress variable, and normalized total enthalpy as conditioning variables to build a three-dimensional conditional manifold for chemistry. In order to map the solution in conditional space into the flow domain, the joint Probability Density Function (PDF) of the conditioning variables needs to be modeled. In simulations, presumed functions (i.e., β-PDF for the mixture fraction and progress variable and δ-PDF for total enthalpy) are often used for modeling the marginal PDFs. In this work, the measurements from the Cambridge/Sandia burner are employed to obtain the marginal PDFs for the conditioning variables at various points in the reacting domain. The measurements are then combined from all positions in space to form conditional PDFs of the normalized total enthalpy for various values of the other two variables. In the vicinity of the flame brush, the marginal PDF of the normalized total enthalpy resembles a bimodal Gaussian distribution; nonetheless, the conditional PDFs for this variable are nearly Gaussian distributions. The correlation coefficients between the conditioning variables are also investigated, and the assumption of their statistical independence is examined. To consider the association between the conditioning variables for modeling, the copula concept is introduced, and the performances of three different copulas are tested. Furthermore, the statistical moments of the conditioning variables are computed from the experimental data at different points and are utilized for modeling the joint PDF of the conditioning variables from two different approaches that are compared.
Displacement speed analysis of surface propagation in moderately turbulent premixed reacting waves
Authors: Pignatelli Francesco , Yu Rixin , Bai Xue-Song , Nogenmyr Karl-Johan
Published: March 2021

The propagation of premixed reacting waves can be characterized by a displacement speed Sd at which the local surface of the reaction progress scalar moves respective to flow. Often, Sd is considered through decomposition into three parts of contribution due to the tangential diffusion of curvature, normal diffusion, and reaction. A set of recently derived transport equations for Sd and three of its decomposed parts provides new diagnostics for better understanding reaction wave propagation in a turbulent environment. In this work, those diagnostics are applied on four similarly setup direct numerical simulation cases studying the propagation of moderately perturbed planar reaction waves into homogeneous turbulence, and the reaction waves differ by the density ratio between fresh and burned gases. The data analysis reveals four self-acceleration behaviors: (i) surfaces propagating at large positive (negative) Sd tend to advance (retreat) faster, (ii) surfaces having large positive (negative) curvature tend to become more curved positively (negatively), (iii) thicken wave zones tend to become thicker, and (iv) surface elements accelerate toward their destruction. The extent of the above accelerations all reduces in the reaction wave having a high density ratio. This can be attributed to the turbulence inhibition due to the flow dilatation and viscosity increase across a thermal-expansion enabled reaction wave. The distribution of curvature for the reaction-zone surface skews toward a negative value, i.e., the curvature center pointing to the burned product.
Mg-implanted bevel edge termination structure for GaN power device applications
Authors: Matys Maciej , Ishida Takashi , Nam Kyung Pil , Sakurai Hideki , Narita Tetsuo , Uesugi Tsutomu , Bockowski Michal , Suda Jun , Kachi Tetsu
Published: March 2021

Herein, we propose and demonstrate the edge termination for GaN-based one-sided abrupt p–n junctions. The structure is comprised of a combination of a shallow negative bevel mesa and selective-area p-type doping under the mesa. Based on the Technology Computer Aided Design (TCAD) simulation, the maximum electric field at the junction edge is markedly reduced to approximately 1.3 times that of the parallel-plane electric field in the proposed structure, which is almost half of the unimplanted diode. The TCAD simulation also shows that the shallow mesa angle of 6° effectively reduces the optimum acceptor concentration (Na) in the implanted region and enhances the breakdown voltage. The optimum Na value can be covered by the proposed technology based on the Mg-ion implantation and subsequent ultra-high-pressure annealing (UHPA). Using the formation of the shallow bevel mesa, the Mg-ion implantation, and the UHPA process, we experimentally demonstrate the p–n diodes with a breakdown voltage over 600 V, which is in good agreement with the TCAD simulation. The proposed method can be applied to a vertical trench-gate metal-oxide-semiconductor field-effect transistor with a high figure-of-merit.
Study of magneto-optical activity in cerium substituted yttrium iron garnet (Ce:YIG) epitaxial thin films
Authors: Kuila Manik , Deshpande Uday , Choudhary R. J. , Rajput Parasmani , Phase D. M. , Raghavendra Reddy V.
Published: March 2021

The study of magneto-optical (MO) properties is reported in epitaxial cerium (Ce) substituted yttrium iron garnet thin films deposited on Gd3Ga5O12 (GGG) substrates using pulsed laser deposition technique at (i) different O2 partial pressure (OPP) during film deposition and (ii) with different film thickness at a given OPP. The MO activity is estimated by measuring the Kerr rotation using the longitudinal magneto-optical Kerr effect with blue (405 nm), green (532 nm), and red (632 nm) incident laser light. The Kerr rotation is observed to increase with an increase in OPP and vary differently with thickness for a given OPP as a function of incident light wavelength. The results are explained in terms of the possible charge transfer mechanism for the films prepared with OPP variation and the optical interference effects in dielectric films with thickness variation.
Electrode shape dependence of output microwave characteristics in reflex triode virtual cathode oscillator
Authors: Tanaka R. , Fukada Y. , Ito H.
Published: March 2021

A virtual cathode oscillator (vircator), which can generate a high-power microwave, has been widely studied over the last four decades. This paper describes the dependence of microwaves and electron beams generated in a reflex triode vircator on the electrode shape and material. The reflex triode vircator is driven by a Marx generator with an output voltage of 200 kV and a stored energy of 240 J. Experiments were conducted with aluminum and velvet cathodes and two types of electrode shapes: (1) circular, with a diameter of 46 mm, and (2) elliptical, with an aspect ratio of 2:3. Both shapes have the same emitting area. Experimental results revealed that the electric field strength of the microwave pulse generated with the elliptical area electrode was 1.3 times greater than that with the circular area electrode. In addition, an x-ray pinhole camera with a beryllium window was used to evaluate the cross-sectional shape of the electron beam. It was found from the x-ray images that the shape of the electron beam was nearly the same as that of the electrode and that the cross-sectional area of the elliptical electron beam was larger than that of the circular electrode although both the circular and elliptical electrodes have the same emitting area. These results show that the electrode shape is one of the important parameters for the vircator.
Higher-order topology in plasmonic Kagome lattices
Authors: Proctor Matthew , Blanco de Paz María , Bercioux Dario , García-Etxarri Aitzol , Arroyo Huidobro Paloma
Published: March 2021

We study the topological properties of a Kagome plasmonic metasurface, modeled with a coupled dipole method that naturally includes retarded long range interactions. We demonstrate that the system supports an obstructed atomic limit phase through the calculation of Wilson loops. Then, we characterize the hierarchy of topological boundary modes hosted by the subwavelength array of plasmonic nanoparticles: both one-dimensional edge modes and zero-dimensional corner modes. We determine the properties of these modes, which robustly confine light at subwavelength scales, calculate the local density of photonic states at edge and corner modes frequencies, and demonstrate the selective excitation of delocalized corner modes in a topological cavity, through nonzero orbital angular momentum beam excitation.
Fractional calculus with exponential memory
Authors: Fu Hui , Wu Guo-Cheng , Yang Guang , Huang Lan-Lan
Published: March 2021

The standard definition of the Riemann–Liouville integral is revisited. A new fractional integral is proposed with an exponential kernel. Furthermore, some useful properties such as composition relationship of the new fractional integral and Leibniz integral law are provided. Exact solutions of the fractional homogeneous equation and the non-homogeneous equations are given, respectively. Finally, a finite difference scheme is proposed for solving fractional nonlinear differential equations with exponential memory. The results show the efficiency and convenience of the new fractional derivative.
Mind Atoms
Authors: Marro Joaquin , Torres Joaquin J.
Published: March 2021

The neuron is a cell, the smallest significant component of the nervous system, that has aroused considerable interest by itself and even more so in conjunction with its surrounding components. Santiago Ramón y Cajal revealed its existence more than a century ago, and it soon attracted so much the curiosity of researchers that this cell has given its name to the study of the whole despite being only part, as today we often talk of neuroscience. This chapter reacts to that interest, specifies a simple glossary for the whole and its parts, and lays the foundation for exploring in the following what can emerge from collaboration between neurons. We anticipate that the secrets of the brain in relation to its unique power and amazing versatility and adaptability should not be sought in this basic cell, as perhaps has been done in the past, but in the new worlds that emerge as a result of its relations with many others. Today this has become obvious just by asking ourselves why a larva of the vinegar fly has 10 000 neurons, whereas this number is multiplied by millions in humans. The ceaseless, intimate, and, in a sense, tricky relationships between neurons and their consequences begin to be rather well known. Describing as accurately as possible the ensuing image, its particulars, and what one can expect next will guide us all the way through this book.
Shaping Relationships
Authors: Marro Joaquin , Torres Joaquin J.
Published: March 2021

The notion of a network or mesh helps us to elucidate the global consequences of relationships. Since these relationships determine a multitude of phenomena—regarding assemblies of molecules, cells, bacteria, ants, fish, humans, companies, or countries, for example—the study of cooperative processes has developed from that perspective; one even witnesses important companies devoted to creating and maintaining nets. A similar motivation makes the notion of networks essential for studying the mind. In this chapter, we lay the foundations for understanding the effects that different degrees of cooperation between neurons can have. And, given that experiments reveal that neuron contacts are not random but structured, we now analyze in detail what mechanisms may have contributed to the creation of the multifaceted brain structures that one observes. The details of these relations, including their strength and time variation, happen to be essential for what emerges from neuronal cooperation, and the resulting situation happens to be rather involved yet interesting. It follows that one needs to assess the consequences of a subtle but fertile competition at the level of neuron connections. On the one hand, there is physical connectivity. We touch on this in the present chapter—see also Park and Friston [Science 342, 1238411 (2013)], for example—with the proviso that function will surely modulate any given structural condition. In fact, it turns out that synapses display plastic adaptability capable of affecting the development of mental processes over various time scales, and that such “malleable wiring,” now perceptible and rather well known, plays a secondary role in practice for the benefit of more functional connectivity—see Stam et al. [Int. J. Psychophysiol. 103, 149 (2016)], for example—which is often partially concealed. Specifically, one observes short-term changes, namely, rapid fluctuations in the synaptic intensities, during function that (eventually but significantly) may either enhance or quieten and even render inoperative some of the physical links. In addition, we will see that a constant process of adaptation of the synaptic intensities is essential and inevitable, perhaps intimately related to those fluctuations. The purpose of this process would be to attain and maintain a critical condition, which optimizes both connectivity and function. In this intriguing context, we begin to study neural wiring.
Switching between perfect absorption and polarization conversion, based on hybrid metamaterial in the GHz and THz bands
Authors: Ha Duong Thi , Ngoc Dzung Dinh , Ngoc Nguyen Van , Son Tung Bui , Pham Thanh Son , Lee YoungPak , Chen Liang Yao , Xuan Khuyen Bui , Dinh Lam Vu
Published: March 2021

We demonstrate a multifunctional metamaterial (MM) structure which can behave like a perfect absorber (PA) or polarization converter (PC) by controlling the lumped varactor. In PC mode, the MM revealed cross-polarization conversion in a frequency range from 2.0 to 7.0 GHz with a polarization-conversion ratio of nearly 100%. While in the PA state, triple-band high absorption was achieved. In addition, we investigated numerically the PA and PC modes by scaling down the geometrical dimension and orientation of the proposed unit cells, for further development of innovative methods in the THz range. Our work is expected to contribute to the realization of future multifunctional MM-based devices working in the GHz or higher-frequency range.
Fabrication of TiO2-based broadband single-layer anti-reflection coating by collimated glancing angle deposition technique
Authors: De Rajnarayan , Haque S Maidul , Sikdar M K , Sahoo P K , Rao K Divakar
Published: March 2021

Single-sided TiO2 thin films were prepared using a modified glancing angle deposition (GLAD) technique. An additional flux collimation plate was introduced into the GLAD arrangement to enhance the degree of collimation of depositing vapour flux. Enhancement in the ballistic growth of film on the substrate was observed with increasing distance from the vapour source. The substrate position near to the vapour source (i.e. bottom region) showed a high refractive index (RI, ∼1.336 @ 550 nm wavelength) and lower average film transmittance (∼94.5% in 400–900 nm wavelength range) compared to the others. In contrast, the TiO2 coating deposited at a distant position from the source (i.e. top region) showed a remarkably low RI (∼1.190 @ 550 nm wavelength) and excellent anti-reflection over a broad spectral region with a maximum average transmittance (∼95.3% in 400–900 nm wavelength) compared to the other substrate positions. The reduction in film RI was correlated qualitatively with the morphological alterations in the coating for different substrate positions. With a further increase in distance from the vapour source, an ultimate reduction in the RI of TiO2 to ∼1.101 was observed, which was ∼50% lower than the bulk TiO2 value (∼2.221 @ 550 nm wavelength). The present study reports the lowest RI of TiO2 together with fabrication of a TiO2-based broadband single-layer anti-reflection coating.
A calculus exercise for physics class: integrating

xne−ax

with two triangles
Authors: Reed B Cameron
Published: March 2021

Integrals of functions of the form

f
(
x
)
=

x

n

e

−
a
x

over the domain

(
0
,
∞
)

occur in various areas of physics. This paper shows how students can evaluate such integrals to surprisingly good accuracy using only basic calculus.
Corrigendum to “Graphs of hyperbolic groups and a limit set intersection theorem”
Authors: Sardar Pranab
Published: March 2021

The purpose of this note is to point out a mistake in the proof of Proposition 4.9 of Proc. Amer. Math. Soc. 146 (2018), 1859–1871 and the consequences thereof.
Well posedness and asymptotic consensus in the Hegselmann-Krause model with finite speed of information propagation
Authors: Haskovec Jan
Published: March 2021

We consider a variant of the Hegselmann-Krause model of consensus formation where information between agents propagates with a finite speed

c

>
0

\mathfrak {c}>0

. This leads to a system of ordinary differential equations (ODE) with state-dependent delay. Observing that the classical well-posedness theory for ODE systems does not apply, we provide a proof of global existence and uniqueness of solutions of the model. We prove that asymptotic consensus is always reached in the spatially one-dimensional setting of the model, as long as agents travel slower than

c

\mathfrak {c}

. We also provide sufficient conditions for asymptotic consensus in the spatially multidimensional setting.
Matched Versus Unmatched Analysis of Matched Case-Control Studies
Authors: Wan Fei , Colditz Graham A , Sutcliffe Siobhan
Published: March 2021

Although the need for addressing matching in the analysis of matched case-control studies is well established, debate remains as to the most appropriate analytical method when matching on at least 1 continuous factor. We compared the bias and efficiency of unadjusted and adjusted conditional logistic regression (CLR) and unconditional logistic regression (ULR) in the setting of both exact and nonexact matching. To demonstrate that case-control matching distorts the association between the matching variables and the outcome in the matched sample relative to the target population, we derived the logit model for the matched case-control sample under exact matching. We conducted simulations to validate our theoretical conclusions and to explore different ways of adjusting for the matching variables in CLR and ULR to reduce biases. When matching is exact, CLR is unbiased in all settings. When matching is not exact, unadjusted CLR tends to be biased, and this bias increases with increasing matching caliper size. Spline smoothing of the matching variables in CLR can alleviate biases. Regardless of exact or nonexact matching, adjusted ULR is generally biased unless the functional form of the matched factors is modeled correctly. The validity of adjusted ULR is vulnerable to model specification error. CLR should remain the primary analytical approach.
Alternative strategies in cardiac preclinical research and new clinical trial formats
Authors: Kreutzer Fabian Philipp , Meinecke Anna , Schmidt Kevin , Fiedler Jan , Thum Thomas
Published: March 2021

An efficient and safe drug development process is crucial for the establishment of new drugs on the market aiming to increase quality of life and life-span of our patients. Despite technological advances in the past decade, successful launches of drug candidates per year remain low. We here give an overview about some of these advances and suggest improvements for implementation to boost preclinical and clinical drug development with a focus on the cardiovascular field. We highlight advantages and disadvantages of animal experimentation and thoroughly review alternatives in the field of three-dimensional cell culture as well as preclinical use of spheroids and organoids. Microfluidic devices and their potential as organ-on-a-chip systems, as well as the use of living animal and human cardiac tissues are additionally introduced. In the second part, we examine recent gold standard randomized clinical trials and present possible modifications to increase lead candidate throughput: adaptive designs, master protocols, and drug repurposing. In silico and N-of-1 trials have the potential to redefine clinical drug candidate evaluation. Finally, we briefly discuss clinical trial designs during pandemic times.
Overexpression of Vitamin D Receptor in Intestinal Epithelia Protects Against Colitis via Upregulating Tight Junction Protein Claudin 15
Authors: Chatterjee Ishita , Zhang Yongguo , Zhang Jilei , Lu Rong , Xia Yinglin , Sun Jun
Published: March 2021

Background and Aims

Dysfunction of the vitamin D receptor [VDR] contributes to the aetiology of IBD by regulating autophagy, immune response, and mucosal permeability. VDR directly controls the paracellular tight junction protein Claudin-2. Claudin-2 and Claudin-15 are unique in maintaining paracellular permeability. Interestingly, claudin-15 mRNA was downregulated in patients with ulcerative colitis. However, the exact mechanism of Claudin-15 regulation in colitis is still unknown. Here, we investigated the protective role of VDR against intestinal inflammation via upregulating Claudin-15.

Methods

We analysed the correlation of Claudin-15 with the reduction of VDR in human colitis. We generated intestinal epithelial overexpression of VDR [O-VDR] mice to study the gain of function of VDR in colitis. Intestinal epithelial VDR knockout [VDR∆IEC] mice were used for the loss of function study. Colonoids and SKCO15 cells were used as in vitro models.

Results

Reduced Claudin-15 was significantly correlated with decreased VDR along the colonic epithelium of human IBD. O-VDR mice showed decreased susceptibility to chemically and bacterially induced colitis and marked increased Claudin-15 expression [both mRNA and protein] in the colon. Correspondingly, colonic Claudin-15 was reduced in VDR∆IEC mice, which were susceptible to colitis. Overexpression of intestinal epithelial VDR and vitamin D treatment resulted in a significantly increased Claudin-15. ChIP assays identified the direct binding of VDR to the claudin-15 promoter, suggesting that claudin-15 is a target gene of VDR.

Conclusion

We demonstrated the mechanism of VDR upregulation of Claudin-15 to protect against colitis. This might enlighten the mechanism of barrier dysfunction in IBD and potential therapeutic strategies to inhibit inflammation.
Antiarrhythmic drugs in patients with early persistent atrial fibrillation and heart failure: results of the RACE 3 study
Authors: Al-Jazairi Meelad I H , Nguyen Bao-Oanh , De With Ruben R , Smit Marcelle D , Weijs Bob , Hobbelt Anne H , Alings Marco , Tijssen Jan G P , Geelhoed Bastiaan , Hillege Hans L , Tieleman Robert G , Van Veldhuisen Dirk J , Crijns Harry J G M , Van Gelder Isabelle C , Blaauw Yuri , Rienstra Michiel ,   for the RACE 3 Investigators
Published: March 2021

Aims

Maintaining sinus rhythm in patients with persistent atrial fibrillation (AF) is challenging. We explored the efficacy of class I and III antiarrhythmic drugs (AADs) in patients with persistent AF and mild to moderate heart failure (HF).

Methods and results

In the RACE 3 trial, patients with early persistent symptomatic AF and short history of mild to moderate HF with preserved or reduced left ventricular ejection fraction (LVEF) were randomized to targeted or conventional therapy. Both groups received AF and HF guideline-driven treatment. Additionally, the targeted-group received mineralocorticoid receptor antagonists, statins, angiotensin-converting enzyme inhibitors and/or receptor blockers, and cardiac rehabilitation. Class I and III AADs could be instituted in case of symptomatic recurrent AF. Eventually, pulmonary vein isolation could be performed. Primary endpoint was sinus rhythm on 7-day Holter after 1-year. Included were 245 patients, age 65 ± 9 years, 193 (79%) men, AF history was 3 (2–6) months, HF history 2 (1–4) months, 72 (29.4%) had HF with reduced LVEF. After baseline electrical cardioversion (ECV), 190 (77.6%) had AF recurrences; 108 (56.8%) received class I/III AADs; 19 (17.6%) flecainide, 36 (33.3%) sotalol, 3 (2.8%) dronedarone, 50 (46.3%) amiodarone. At 1-year 73 of 108 (68.0%) patients were in sinus rhythm, 44 (40.7%) without new AF recurrences. Maintenance of sinus rhythm was significantly better with amiodarone [n = 29/50 (58%)] compared with flecainide [n = 6/19 (32%)] and sotalol/dronedarone [n = 9/39 (23%)], P = 0.0064. Adverse events occurred in 27 (25.0%) patients, were all minor and reversible.

Conclusion

In stable HF patients with early persistent AF, AAD treatment was effective in nearly half of patients, with no serious adverse effects reported.