bluuebunny/crossref_metadata_2025 huggingface dataset:
Increase in Pediatric Intensive Care Unit Hospitalizations Due to Toxic Ingestions during the COVID-19 Pandemic
Authors: van Helmond Jennifer L. , Fitts Brittany , Chauhan Jigar C.
Published: May 2021

The coronavirus disease 2019 (COVID-19) pandemic and related community mitigation measures had a significant psychosocial impact. We suspected that more patients were admitted to our pediatric intensive care unit (PICU) for toxic ingestions since the start of the pandemic. We therefore investigated if PICU admissions related to toxic ingestions were higher in 2020 as a result of COVID-19 compared with previous years. We completed a cross-sectional study at a tertiary children's hospital comparing admissions to our PICU between April 2020 and October 2020, during which COVID-19 and community mitigation measures were in place, to those during the same 7-month period in the previous 3 years. Total PICU admissions, admissions for all toxic ingestions (intentional ingestions and accidental ingestions), and demographic and clinical characteristics of patients were compared. Total PICU admissions in 2020 during COVID-19 pandemic months were lower compared with the same months in the preceding 3 years (−16%, p< 0.001), however, admissions for toxic ingestions were higher during COVID-19 (+64%, p< 0.001). When separated by type, intentional (+55%, p = 0.012) and accidental ingestions (+94%, p = 0.021) were higher during COVID-19. COVID-19 with community mitigation measures has led to an increase in PICU admissions for intentional and accidental ingestions, indicating an increase in severity of toxic ingestions in children associated with the pandemic. Mental health of adolescents, and safety of infants and toddlers in their home environment, should be targeted with specific interventions in the ongoing COVID-19 pandemic.
Macroeconomic factors, working capital management, and firm performance—A static and dynamic panel analysis
Authors: Hussain Sarfraz , Nguyen Van Chien , Nguyen Quang Minh , Nguyen Huu Tinh , Nguyen Thu Thuy
Published: May 2021

The aim of the study is to explore the interaction effect of macroeconomics indicators, and working capital flows on financial performance in a developing economy. By using the static and dynamic approach of panel analysis, it has been shown that there is a relationship between the components of working capital and the gross profit and cash conversion duration. Second, while interest rates used as an interaction variable with the average payable days have adverse effects, firm performance would decrease if interest rates increase. The average payable duration extends; instead of primarily regressing, the average payable period positively correlates with firm performance. The conversion cycle of cash has a negative relationship, but it reverses its actions after using interest rate interaction. There is a negative relationship with gross profit in the simple regression exchange rate and cash conversion cycle while using the second interaction variable with the cash conversion cycle, has positive effects. In addition, the exchange rate gets higher to increase the cash conversion length, financial performance will be increased. In addition, the exchange rate gets higher to increase the cash conversion length, financial performance will be increased. This study receives new results, the exchange rate increases, companies that can pay early to payable will get higher firm performance while exchange rate and the interest rate have a significant role in changing the firm performance.
Hydrogen density-of-states distribution in β-Ga2O3
Authors: Nickel N. H. , Geilert K.
Published: May 2021

Hydrogen bonding in β-Ga2O2 is investigated using hydrogen effusion measurements. The samples were grown by plasma-assisted pulsed laser deposition. With increasing deposition temperature, the total H concentration decreases from 8.1 × 1019 to 9.2 × 1018 cm−3. The dependence of the hydrogen chemical potential, μH, on the H concentration is derived from the effusion spectra and subsequently used to determine the H density-of-states distribution. β-Ga2O2 deposited at Tdep ≤ 723 K exhibits a needle-like peak in the H density-of-states distribution at ≈1.8 eV below the H transport states. With increasing Tdep, the H density-of-states changes and two broad peaks emerge that are located at ≈1.7 and 2.4 eV below the H transport states for Tdep ≥ 873 K.
Single-carrier charge collection in thin direct-conversion semiconductor neutron detector: A numerical simulation
Authors: Bhattarai Gyanendra , Caruso Anthony N. , Paquette Michelle M.
Published: May 2021

Although direct-conversion solid-state neutron detection has been investigated for over five decades, propelling this technology beyond the basic research stage remains an outstanding challenge. This challenge is due to the very small selection of neutron-sensitive isotopes and therefore lack of mature semiconductor materials available for this technology. Given these constraints, there is a reason to investigate materials with less-than-optimal charge transport properties, which could include low charge carrier mobility/lifetime and/or single-carrier transport (i.e., order of magnitude or greater difference between electron and hole mobility). Such materials are potentially best-suited to a thin-film configuration, which provides not only leniency in terms of charge transport requirements, but also processing flexibility and integration advantages. Single-carrier transport in detectors with thicknesses less than or comparable to radiation penetration depth can lead to partial and position-dependent charge collection effects not treated in the general case of direct-conversion neutron detection. Here, we have developed a theory to include the effect of single-carrier charge collection and the possible mismatch between carrier transit time and integration time to study the performance of thin neutron detectors. Taking a boron carbide (B4C) direct-conversion thermal neutron detector as an example, we use custom Monte Carlo simulations to study the effects of a range of mobility, lifetime, thickness, and integration time values on detection efficiency and pulse height spectra. We discuss the interplay between the traditional mobility–lifetime product (μτ) metric and the integration time to carrier transit time ratio (ti/ttr), which takes into account mobility (μ) specifically, and their effect on detection efficiency. We describe the effect of these parameters on pulse height spectra and show how, although single-carrier transport leads to a loss of spectral resolution when signal current is fully integrated, using integration times shorter than carrier transit time allows for recovery of spectral features. We additionally present two methods to extract the mobility–lifetime product of a single-carrier device, with the first being based on the steady-state current as a function of electric field under a steady-state radiation detection mode, and the second being based on the shift of spectral peaks as a function of electric field under a single-particle radiation counting mode, both using modified Hecht equations that do not require either surface or uniform radiation absorption conditions. Finally, we discuss the performance of a hypothetical single-carrier 5 μm thick B4C neutron detector, which can provide a maximum intrinsic neutron detection efficiency of 14% with a set lower level discriminator value of 25% of the total energy deposited.
Numerical simulation of the cathode erosion by ion sputtering in hollow cathode arc discharges
Authors: Cong Shiyuan , Sun Jizhong , Jin Wei , Wang Dezhen
Published: May 2021

Cathode erosion by ion sputtering is one of the primary erosion mechanisms in hollow cathode discharges. In this paper, the moving mesh approach coupling with a two-dimensional plasma fluid model was employed to simulate the cathode erosion process for 100 h in a hollow cathode arc discharge. In the numerical model, plasma transport, arc flow and heating, and cathode thermal balance were considered. In addition, the electron emission, ion bombardment, and surface radiation were taken into account on the cathode wall. The normal erosion depth on the cathode surface was defined to characterize the degree of cathode erosion. The results showed that the ion sputtering erosion was sensitive to the ion flux toward the cathode wall and the distribution of the plasma potential. The external magnetic field could mitigate the erosion process. The changes of erosion depth and position under different discharge currents, gas flow rates, and intensities of the applied magnetic field were also investigated in this paper.
Internal magnetic measurement in collisional-merging process of a field-reversed configuration
Authors: Watanabe T. , Asai T. , Takahashi Ts. , Kobayashi D. , Harashima D.
Published: May 2021

An internal magnetic probe array has been developed to observe the three components of the magnetic field simultaneously in the vicinity of the collision surface of two colliding plasmoids at supersonic/Alfvénic velocity. Collisional-merging formation of a field-reversed configuration (FRC) has been conducted in the (FRC Amplification via Translation-Collisional Merging) device at Nihon University. Significant plasma heating and an increase in trapped poloidal magnetic flux have been observed during/after the collisional-merging process in the FAT-CM device. In this dynamic formation process, two FRC-like plasmoids formed by a field-reversed theta-pinch method collide in the middle of the confinement chamber at a relative speed of 200–400 km/s. Therefore, the excited shockwave is considered as one of the heating mechanisms. The developed probe array installed in the middle of the confinement chamber observes the internal structure of the magnetic field. The probe consists of 12 sets of three-axis chip inductors arranged at intervals of 40 mm. The measurement position can be varied in the radial direction. In the single translation and collisional-merging experiment, the internal magnetic probe measures the magnetic field’s radial distribution with a high time resolution under noise.
Influence of plasmonic resonant wavelength on energy transfer from an InGaN quantum well to quantum dots
Authors: Zhuang Zhe , Li Cheng , Zhang Yun , Liu Bin , Zhang Xiong , Fan Aijie , Chen Shuai , Lu Liang , Cui Yiping
Published: May 2021

We demonstrated the enhanced nonradiative resonant energy transfer (NRET) process by localized surface plasmon (LSP) in the hybrid InGaN quantum well (QW) and CdSe/ZnS quantum dot (QD) structures. The LSP resonant wavelengths could be adjusted by silver (Ag) nanoparticle (NP) arrays annealed from different thicknesses of Ag films. The LSP resonant wavelengths that are close to the peak QD emission helped to enhance the NRET between the QW and QDs. Compared to the original NRET in the absence of Ag NPs, the LSP-enhanced NRET rate was improved by 6.9 times at the resonant wavelength of 600 nm. The calculated efficiency of the LSP-enhanced NRET was 73.1%, which was almost twice that of the original efficiency. Although Ag NPs exhibited a quenching effect, the LSP-enhanced NRET at the resonant wavelength of 465 nm enhanced QD luminescence, which demonstrated their potential use in energy conversion devices.
Vacancy diffusion and nitrogen-vacancy center formation near the diamond surface
Authors: Räcke P. , Pietzonka L. , Meijer J. , Spemann D. , Wunderlich R.
Published: May 2021

For the engineering of nitrogen-vacancy (NV) centers in diamond, vacancies have been introduced locally into a type Ib diamond (100–200 ppm nitrogen content) by implanting argon ions from a sub-500 nm focused beam. At an acceleration potential of 12 kV, different charge states (Ar n+, n={1,4,8,11}) result in kinetic energies of 12–132 keV. NV-centers were formed by a subsequent annealing step. A wide range of fluences from around one ion to several hundred ions was implanted per spot. It was found that, on average, between 0.04 (12 keV) and 0.79 (132 keV) NV-centers are created from the vacancies of a single implanted argon ion, depending on the ion energy, but not on the fluence. The different number of vacancies created at each energy alone cannot account for the difference in NV-center yield. However, the probability of a given vacancy to diffuse to the diamond surface during annealing, where it cannot contribute to NV-center formation, was simulated and can fully explain the NV-yield behavior. With this model, an upper bound of approximately 300 nm for the diffusion length of a single vacancy was found for an annealing temperature of 800 °C.
Evolutionary design of nano-cavity-based antireflective layers
Authors: Briones Edgar , Gonzalez Fernando , Ruiz-Cruz Riemann , Briones Joel
Published: May 2021

Inspired by the extraordinary ability of metallic resonant nano-cavities to transmit light toward a substrate beneath them, the authors introduce quite a simple design of nano-cavities displaying enhanced antireflective properties in the UV–vis band. With the aid of an evolutionary algorithm, which is based on social rules, the authors drive the dimensions of a hexagonal periodic array of nano-cavities to induce an enhanced reflectance decrease in a silicon substrate as well as a strong increase in the transmittance through it. By using finite-element simulations in the real space, the physical mechanism behind the light propagation is subsequently unveiled.
Effect of ZnO cap layer deposition environment on thermal stability of the electrical properties of Al-doped ZnO films
Authors: Zhang Yufeng , Fei Ziqi , Huang Huang , Zhang Xue-ao , Mu Rui
Published: May 2021

Al-doped ZnO (AZO) is a promising candidate as a transparent conducting electrode. However, the electrical properties of AZO deteriorate greatly after exposing it to excessive heat. This limits the applications of AZO in devices that experience a demanding operation environment. It has been shown that a ZnO cap layer with proper morphology is capable to dramatically improve the thermal stability of AZO. However, the detailed mechanism is not yet clear. A comparison study of the electrical properties of AZO with a ZnO cap layer prepared by magnetron sputtering (MS) at low substrate temperature (70 °C) and chemical vapor deposition (CVD) at high substrate temperature (600 °C) indicates that MS-prepared ZnO is much less effective in protecting AZO from an oxidizing environment under elevated temperature than the CVD-prepared ZnO. The morphology and crystal structures of two types of ZnO/AZO, investigated by a scanning electron microscope and x-ray diffraction, are relatively similar, whereas the atomic structures (e.g., defects) revealed by Raman spectroscopy are rather different. The results suggest that it is difficult to improve the thermal stability of electrical properties of AZO without a proper restructuring process and a ZnO cap layer that could sacrifice its own structural order. The discoveries offer a novel approach to improve the performance of other transparent conducting oxides.
Symplectic Gaussian process regression of maps in Hamiltonian systems
Authors: Rath Katharina , Albert Christopher G. , Bischl Bernd , von Toussaint Udo
Published: May 2021

We present an approach to construct structure-preserving emulators for Hamiltonian flow maps and Poincaré maps based directly on orbit data. Intended applications are in moderate-dimensional systems, in particular, long-term tracing of fast charged particles in accelerators and magnetic plasma confinement configurations. The method is based on multi-output Gaussian process (GP) regression on scattered training data. To obtain long-term stability, the symplectic property is enforced via the choice of the matrix-valued covariance function. Based on earlier work on spline interpolation, we observe derivatives of the generating function of a canonical transformation. A product kernel produces an accurate implicit method, whereas a sum kernel results in a fast explicit method from this approach. Both are related to symplectic Euler methods in terms of numerical integration but fulfill a complementary purpose. The developed methods are first tested on the pendulum and the Hénon–Heiles system and results compared to spectral regression of the flow map with orthogonal polynomials. Chaotic behavior is studied on the standard map. Finally, the application to magnetic field line tracing in a perturbed tokamak configuration is demonstrated. As an additional feature, in the limit of small mapping times, the Hamiltonian function can be identified with a part of the generating function and thereby learned from observed time-series data of the system’s evolution. For implicit GP methods, we demonstrate regression performance comparable to spectral bases and artificial neural networks for symplectic flow maps, applicability to Poincaré maps, and correct representation of chaotic diffusion as well as a substantial increase in performance for learning the Hamiltonian function compared to existing approaches.
Thermal and oxidation stability of TixW1−x diffusion barriers investigated by soft and hard x-ray photoelectron spectroscopy
Authors: Kalha C. , Bichelmaier S. , Fernando N. K. , Berens J. V. , Thakur P. K. , Lee T.-L. , Gutiérrez Moreno J. J. , Mohr S. , Ratcliff L. E. , Reisinger M. , Zechner J. , Nelhiebel M. , Regoutz A.
Published: May 2021

The binary alloy of titanium-tungsten (TiW) is an established diffusion barrier in high-power semiconductor devices, owing to its ability to suppress the diffusion of copper from the metallization scheme into the surrounding silicon substructure. However, little is known about the response of TiW to high-temperature events or its behavior when exposed to air. Here, a combined soft and hard x-ray photoelectron spectroscopy (XPS) characterization approach is used to study the influence of post-deposition annealing and titanium concentration on the oxidation behavior of a 300 nm-thick TiW film. The combination of both XPS techniques allows for the assessment of the chemical state and elemental composition across the surface and bulk of the TiW layer. The findings show that in response to high-temperature annealing, titanium segregates out of the mixed metal system and upwardly migrates, accumulating at the TiW/air interface. Titanium shows remarkably rapid diffusion under relatively short annealing timescales, and the extent of titanium surface enrichment is increased through longer annealing periods or by increasing the bulk titanium concentration. Surface titanium enrichment enhances the extent of oxidation both at the surface and in the bulk of the alloy due to the strong gettering ability of titanium. Quantification of the soft x-ray photoelectron spectra highlights the formation of three tungsten oxidation environments, attributed to WO2, WO3, and a WO3 oxide coordinated with a titanium environment. This combinatorial characterization approach provides valuable insights into the thermal and oxidation stability of TiW alloys from two depth perspectives, aiding the development of future device technologies.
Connecting the quantum and classical mechanics simulation world: Applications of reactive step molecular dynamics simulations
Authors: Biedermann Myra , Diddens Diddo , Heuer Andreas
Published: May 2021

This article presents the application of the reactive step molecular dynamics simulation method [M. Biedermann, D. Diddens, and A. Heuer, J. Chem. Theory Comput. 17, 1074 (2021)] toward two different atomistic, chemically reactive systems. During reactive steps, transitions from reactant to product molecules are modeled according to physically correct transition probabilities based on quantum chemical information about the reactions such as molecular reaction rates via instant exchange of the employed force field and a subsequent, short relaxation of the structure. In the first application, we study the follow-up reactions of singly reduced ethylene carbonate (EC) radicals in EC solution, first, via extensive ab initio molecular dynamics simulations and, second, with the reactive step algorithm. A direct comparison of both simulation methods shows excellent agreement. Then, we employ the reactive step algorithm to simulate the enolate formation of 2-methylcyclopropanone with the base lithium diisopropylamine. Thereby, we can demonstrate that the reactive step algorithm is also capable of capturing effects from kinetic vs thermodynamic control of chemical reactions during simulation.
Flexoelectric response of ferroelectric ceramics with reduced surface layer effect
Authors: Tian Dongxia , Hou Yu , Zhou Wanfeng , Chu Baojin
Published: May 2021

The flexoelectric response of Na0.5Bi0.5TiO3-based and (Ba,Sr)TiO3 ferroelectric ceramics with sputtered or fired-on Ag, Au, and Ag/Pd electrodes was investigated. We found that for all the ceramics, the flexoelectric response of the same material is strongly dependent on the methods used to fabricate the electrodes. The samples with fired-on electrodes have a much smaller flexoelectric response than those with sputtered electrodes, and for a certain composition, the flexoelectric response can be reduced by more than 99%. The reduction of flexoelectric response is attributed to the suppression of the contribution from the spontaneously polarized surface layers on ferroelectric ceramics to the flexoelectric response. Three reasons were proposed for the suppression of the surface effect, namely, the diffusion of some substances in electrode pastes to the surface regions of ferroelectric ceramics, stress relief, and the generation of impurity phases caused by the evaporation of volatile element during the firing of electrode materials at a high temperature. We also found that the flexoelectric response can approach the theoretically predicated response after the surface effect is reduced by fabricating fired-on electrodes on ferroelectric ceramics. Our results indicate that the large flexoelectric response of ferroelectric ceramics is mainly from the polarized surface layers and the surface effect is the primary mechanism leading to the deviation of measured flexoelectric response from the intrinsic response in ferroelectric ceramics, which has been an unresolved issue in the flexoelectric research field.
Spectral optical vortex modulation from geometric phase diamond metasurface arrays
Authors: Ghadimi Nassiri Mikaël , Seniutinas Gediminas , David Christian , Juodkazis Saulius , Brasselet Etienne
Published: May 2021

Agile management of the optical orbital angular momentum encompasses temporal, spatial, and spectral aspects that, once combined, offer new perspectives in our way to manipulate light. To date the spectral control is mainly limited to tunable operating wavelength and polychromatic capabilities. Recently, a multispectral approach has been proposed [Phys. Rev. Lett. 121, 213901 (2018)] to achieve independent orbital angular momentum state control on multiple spectral channels. Here we report on the design, fabrication and implementation of a solid-state multispectral approach that consists of arrays of optical diamond micro-metasurfaces. Obtained device exhibits superior performances with respect to the original attempt, both regarding the spectral vortex purity, the ability to deal with high photon flux, and the orbital angular momentum diversity across the spectrum. These results motivate further development of metasurface-based integrated spin–orbit photonics technologies.
Modulation of viscous planar jump by an obstacle in the flow path—Interrogation through shallow water equations and numerical analysis
Authors: Dhar Mrinmoy , Ray Subhabrata , Das Gargi , Das Prasanta Kumar
Published: May 2021

The paper investigates a planar hydraulic jump during a thin film flow over a two-dimensional obstacle spanning the entire width of a horizontal channel. The shallow water analysis supported by numerical simulations identifies a hydraulic drop and simultaneous jump-drop-jump phenomenon under certain flow conditions. A hydraulic drop although observed for flow over obstacles in the macro-domain has never been reported for a thin film flow. The study, thus, establishes the efficacy of shallow water analysis which, with a novel solution methodology, predicts jump and drop characteristics over obstacles with much less computational effort compared to computational fluid dynamics based simulations. In addition, analytical expressions for jump efficiency and head loss across jump along with energy dissipation analysis are provided for a viscous jump. The numerical simulations reveal recirculation zones close to the channel floor and at the free surface, and the energy dissipation analysis provides a quantitative criterion for formation of recirculation zone pair. The observations are consolidated as a phase diagram which characterizes a myriad of free surface profiles based on operating and geometrical parameters.
Proposal of a compact grating-based phase contrast imaging system using an x-ray polycapillary lens
Authors: Chi Zhijun
Published: May 2021

As the grating-based phase contrast imaging has drawn much attention in various scientific fields, there is an increasing demand for a compact imaging system with high efficiency in practical applications. In this paper, a compact imaging configuration by replacing the source grating in a conventional imaging system with a robust, easily-fabricated, and cost-effective x-ray polycapillary lens is proposed and its feasibility is examined using a full-scale Monte Carlo simulation. A typical x-ray spectrum for diagnostic mammography is adopted in the simulation. Under this spectrum, a new polycapillary lens is designed and optimized to meet the requirement of the imaging system. The phantom consists of polyethylene, cortical bone, and adipose tissue spheres of different sizes. An accurate phase image of the phantom is successfully reconstructed using an eight-step phase-stepping method. Excellent agreement of the phase shift and attenuation of the phantom is obtained between the simulation and the theoretical prediction. Compared with a conventional imaging system using a source grating at the same parameters, the imaging efficiency of our proposed system is improved 1.7 times, while its background visibility is reduced from 44.4% to 12.4%. Our results suggest the possibility of developing such a bench-top system for flexible phase contrast imaging applications.
Vortex polygons: Dynamics and associated particle advection
Authors: Espinosa Ramírez A. C. , Velasco Fuentes Oscar
Published: May 2021

This paper presents a numerical study of the advection of passive and active particles by three and four equal vortices located on the vertices of a polygon. The vortices, which have either singular or uniform vorticity distribution, are immersed in an incompressible, unbounded, and inviscid fluid. Under these conditions, a regular polygon rotates steadily if it consists of point vortices and unsteadily if it consists of Rankine vortices. When the point-vortex polygon is perturbed by making it slightly irregular, the flow becomes time periodic. In this case, dynamical-system methods, such as lobe dynamics and Poincaré maps, serve to compute the fluid exchanged between different regions and the area of the chaotic sea. Both quantities are found to grow with the amplitude of the perturbation: the former does it in a weakly nonlinear way, the latter in a piecewise linear manner. The Rankine-vortex polygons always produce a time-aperiodic flow, which depends on their relative size. Small vortices deform slightly and produce particle advection, which is analogous to the perturbed point-vortex case; large vortices deform strongly and merge to form a single one. The critical distance for merger is found to be δ/a≈3.6 and δ/a≈3.2 for three and four vortices, respectively, where a is the vortex radius, and δ is the side length of the polygon. In both cases, the vortices expel the largest amount of vortical fluid at their critical distance, thus producing the least efficient merger.
On the magnetization of dilute ferrofluid emulsions in shear flows
Authors: Abicalil Victor Guinancio e , Abdo Rodrigo Figueiredo , da Cunha Lucas Hildebrand Pires , de Oliveira Taygoara Felamingo
Published: May 2021

A 3D numerical investigation on the magnetization of dilute magnetic emulsions subjected to shear flows and external magnetic fields is carried out. The present study is an extension of the previous work of Cunha et al. [“Effects of external magnetic fields on the rheology and magnetization of dilute emulsions of ferrofluid droplets in shear flows,” Phys. Fluids 32, 073306 (2020)] for the 2D analogous system. The ferrofluid is assumed superparamagnetic such as the bulk magnetization depends on droplet shape and orientation. The magnetic field is applied in the main flow, main velocity gradient, and main vorticity directions. For the two former cases, the emulsion magnetization does not perfectly align with the external field, such stronger shear rates leading to larger misalignment angles. For fields parallel with flow direction, stronger fields lead to a decrease in this misalignment angle, while for external magnetic fields in the main velocity gradient direction, stronger magnetic fields lead to an increase in misalignment angle. Although these results are qualitatively similar to those presented by Cunha et al. [“Effects of external magnetic fields on the rheology and magnetization of dilute emulsions of ferrofluid droplets in shear flows,” Phys. Fluids 32, 073306 (2020)], the misalignment angles observed are significantly smaller than those of the analogous 2D. The magnetic forces at the droplet interface create a magnetic torque in the emulsion, resulting in asymmetries of the bulk stress tensor. For external magnetic fields in the main velocity gradient direction, magnetic torques increase monotonically with increasing field intensities, while for external fields in the main velocity direction, magnetic torques are smaller and remain roughly constant for Camag > 8. We observed that the magnetic field applied in the main vorticity direction may lead to oblate droplets, rather than the more conventional prolate one.
Structural basis for p50RhoGAP BCH domain–mediated regulation of Rho inactivation
Authors: Chichili Vishnu Priyanka Reddy , Chew Ti Weng , Shankar Srihari , Er Shi Yin , Chin Cheen Fei , Jobichen Chacko , Qiurong Pan Catherine , Zhou Yiting , Yeong Foong May , Low Boon Chuan , Sivaraman J.
Published: May 2021

Significance

Small GTPases are binary proteins that rapidly switch between active and inactive states through the actions of GEF- and GTPase-activating proteins (GAPs), respectively. GAPs play significant roles in cellular signaling, and their dysregulation is linked to numerous cancers. Here, we show that the BNIP-2 and Cdc42GAP Homology (BCH) domain of p50RhoGAP, known to autoinhibit the adjacent GAP domain, adopts an intertwined, dimeric structure with unique RhoA interactions. The β5-strand of the BCH domain plays a crucial role in the autoinhibition of the GAP domain. A mutation in the β5-strand destabilizes this autoinhibition and leads to RhoGAP activation. Our studies on the dynamics of the RhoGAP BCH domain will clarify its potential role in cancer and other diseases.
The immune response is a critical regulator of zebrafish retinal pigment epithelium regeneration
Authors: Leach Lyndsay L. , Hanovice Nicholas J. , George Stephanie M. , Gabriel Ana E. , Gross Jeffrey M.
Published: May 2021

Loss of the retinal pigment epithelium (RPE) because of dysfunction or disease can lead to blindness in humans. Harnessing the intrinsic ability of the RPE to self-repair is an attractive therapeutic strategy; however, mammalian RPE is limited in its regenerative capacity. Zebrafish possess tremendous intrinsic regenerative potential in ocular tissues, including the RPE, but little is known about the mechanisms driving RPE regeneration. Here, utilizing transgenic and mutant zebrafish lines, pharmacological manipulations, transcriptomics, and imaging analyses, we identified elements of the immune response as critical mediators of intrinsic RPE regeneration. After genetic ablation, the RPE express immune-related genes, including leukocyte recruitment factors such as
interleukin 34
. We demonstrate that macrophage/microglia cells are responsive to RPE damage and that their function is required for the timely progression of the regenerative response. These data identify the molecular and cellular underpinnings of RPE regeneration and hold significant potential for translational approaches aimed toward promoting a pro-regenerative environment in mammalian RPE.
Ku70 suppresses alternative end joining in G1-arrested progenitor B cells
Authors: Liang Zhuoyi , Kumar Vipul , Le Bouteiller Marie , Zurita Jeffrey , Kenrick Josefin , Lin Sherry G. , Lou Jiangman , Hu Jianqiao , Ye Adam Yongxin , Boboila Cristian , Alt Frederick W. , Frock Richard L.
Published: May 2021

Significance

Alternative end joining (A-EJ) is implicated in oncogenic translocations and mediating DNA double-strand-break (DSB) repair in cycling cells when classical nonhomologous end-joining (C-NHEJ) factors of the C-NHEJ ligase complex are absent. However, V(D)J recombination-associated DSBs that occur in G1 cell cycle-phase progenitor lymphocytes are joined exclusively by the C-NHEJ pathway. Until now, however, the overall mechanisms that join general DSBs in G1-phase progenitor B cells had not been fully elucidated. Here, we report that Ku, a core C-NHEJ DSB recognition complex, directs repair of a variety of different targeted DSBs toward C-NHEJ and suppresses A-EJ in G1-phase cells. We suggest this Ku activity explains how Ku deficiency can rescue the neuronal development and embryonic lethality phenotype of ligase 4-deficient mice.
The conceptual importance of grammar
Authors: van Rijt Jimmy H.M , Coppen Peter-Arno J. M.
Published: May 2021

Knowledge about Language (KaL) is an important part of L1 language education around the world. A controversial
part of KaL is grammatical or syntactic knowledge, i.e., knowledge about the form, meaning and use of sentences and phrases. In
the current international discourse on L1 grammar teaching, grammar is principally motivated by the desire to enhance students’
literacy development, befitting the communicative turn in mother tongue education and following high quality research which has
shown that contextualized grammar teaching can impact on students’ writing development. However, there are also other potentially
meaningful reasons to teach grammar, which remain underresearched and underdiscussed in curriculum discussions: (1) the general
importance of language justifies that L1 speakers understand how their language works; (2) grammar teaching provides more insight
into the workings of the human mind; (3) grammar teaching can be used to facilitate students’ reasoning and stimulate their
critical thinking abilities. These reasons for teaching grammar do not necessarily relate to literacy development; rather, they
pertain to a general conceptual importance of knowledge about grammar. This paper explores these arguments and argues, partly
based on empirical evidence from recent research, that knowledge-related rationales deserve a more prominent place in curriculum
discussions about grammar teaching.
The Borel-Kolmogorov Paradox Is Your Paradox Too: A Puzzle for Conditional Physical Probability
Authors: Meehan Alexander , Zhang Snow
Published: May 2021

The Borel-Kolmogorov paradox is often presented as an obscure problem that certain mathematical accounts of conditional probability must face. In this article, we point out that the paradox arises in the physical sciences, for physical probability or chance. By carefully formulating the paradox in this setting, we show that it is a puzzle for everyone, regardless of one’s preferred probability formalism. We propose a treatment that is inspired by the approach that scientists took when confronted with these cases.
Silicon-assisted growth of hexagonal boron nitride to improve oxidation resistance of germanium
Authors: Zhang Chao , Gao Boxiang , Ran Yihua , Shi Zhiyuan , Zhu Hongyan , Zhang Hui , Liu Jian , Yang Bo , Liu Zhi , Wu Tianru , Xie Xiaoming
Published: May 2021

Hexagonal boron nitride (h-BN) is an exciting two dimensional dielectric due to its atomic flatness, free of dangling bonds, exceptional thermal and chemical stabilities. Here we report a method of silicon-assisted synthesis of monolayer h-BN on germanium (Ge) by chemical vapor deposition. The silicon atoms dissolve into Ge (110) and promote the growth of h-BN domains by formation of Si–N bonds. The oxidation dynamic shows that monolayer h-BN film is a high-performance passivation layer, preserving Ge from oxidation in air at high temperature. This work sheds lights on the outstanding oxidation resistance of h-BN for further Ge-based electronic devices.
Preparation and thermoelectric properties of screen-printable rGO/Sb2Te3/SV4/PEDOT:PSS composite thermoelectric film
Authors: Zhu Qiqi , Du Yong , Meng Qiufeng , Shen Shirley Z
Published: May 2021

Because of the advantages of facile and fast preparation process, screen printing technology shows great potentials in the prospective large-scale production of thermoelectric materials. Herein, rGO/Sb2Te3 composite powders have been prepared by a hydrothermal process, and then flexible rGO/Sb2Te3/SV4/PEDOT:PSS composite films with different weights of rGO/Sb2Te3 composite powders have been prepared via a screen printing process. The effects of the contents of rGO/Sb2Te3 composite powders on thermoelectric properties of the rGO/Sb2Te3/SV4/PEDOT:PSS composite films have been studied. The Seebeck coefficients of the achieved composite films was basically unchanged with the content of rGO/Sb2Te3 composite powders increasing, whereas the electrical conductivities decrease, resulting in a maximal power factor of 2.96 μW/mK2 at 375 K for the composite film containing 85 wt.% rGO/Sb2Te3 composite powders. The cold pressing combining annealing process has been employed to improve the thermoelectric properties of the composite films. After the treatment, the electrical conductivity of the composite film with 85 wt.% rGO/Sb2Te3 powders has been significantly improved, while the corresponding Seebeck coefficient has slightly decreased. An optimal power factor of 14.13 μW/mK2 has been acquired at 375 K, which is ∼ 5 times higher when compared to the untreated composite film (2.96 μW/mK2 at 375 K).
Patient specific, imaging-informed modeling of rhenium-186 nanoliposome delivery via convection-enhanced delivery in glioblastoma multiforme
Authors: Woodall Ryan T , Hormuth II David A , Wu Chengyue , Abdelmalik Michael R A , Phillips William T , Bao Ande , Hughes Thomas J R , Brenner Andrew J , Yankeelov Thomas E
Published: May 2021

Convection-enhanced delivery of rhenium-186 (186Re)-nanoliposomes is a promising approach to provide precise delivery of large localized doses of radiation for patients with recurrent glioblastoma multiforme. Current approaches for treatment planning utilizing convection-enhanced delivery are designed for small molecule drugs and not for larger particles such as 186Re-nanoliposomes. To enable the treatment planning for 186Re-nanoliposomes delivery, we have developed a computational fluid dynamics approach to predict the distribution of nanoliposomes for individual patients. In this work, we construct, calibrate, and validate a family of computational fluid dynamics models to predict the spatio-temporal distribution of 186Re-nanoliposomes within the brain, utilizing patient-specific pre-operative magnetic resonance imaging (MRI) to assign material properties for an advection-diffusion transport model. The model family is calibrated to single photon emission computed tomography (SPECT) images acquired during and after the infusion of 186Re-nanoliposomes for five patients enrolled in a Phase I/II trial (NCT Number NCT01906385), and is validated using a leave-one-out bootstrapping methodology for predicting the final distribution of the particles. After calibration, our models are capable of predicting the mid-delivery and final spatial distribution of 186Re-nanoliposomes with a Dice value of 0.69 ± 0.18 and a concordance correlation coefficient of 0.88 ± 0.12 (mean ± 95% confidence interval), using only the patient-specific, pre-operative MRI data, and calibrated model parameters from prior patients. These results demonstrate a proof-of-concept for a patient-specific modeling framework, which predicts the spatial distribution of nanoparticles. Further development of this approach could enable optimizing catheter placement for future studies employing convection-enhanced delivery.
Influential Periods in Longitudinal Clinical Cardiovascular Health Scores
Authors: Krefman Amy E , Labarthe Darwin , Greenland Philip , Pool Lindsay , Aguayo Liliana , Juonala Markus , Kähönen Mika , Lehtimäki Terho , Day R Sue , Bazzano Lydia , Muggeo Vito M R , Van Horn Linda , Liu Lei , Webber Larry S , Pahkala Katja , Laitinen Tomi T , Raitakari Olli , Lloyd-Jones Donald M , Allen Norrina B
Published: May 2021

The prevalence of ideal cardiovascular health (CVH) among adults in the United States is low and decreases with age. Our objective was to identify specific age windows when the loss of CVH accelerates, to ascertain preventive opportunities for intervention. Data were pooled from 5 longitudinal cohorts (Project Heartbeat!, Cardiovascular Risk in Young Finns Study, The Bogalusa Heart Study, Coronary Artery Risk Development in Young Adults, Special Turku Coronary Risk Factor Intervention Project) from the United States and Finland from 1973 to 2012. Individuals with clinical CVH factors (i.e., body mass index, blood pressure, cholesterol, blood glucose) measured from ages 8 to 55 years were included. These factors were categorized and summed into a clinical CVH score ranging from 0 (worst) to 8 (best). Adjusted, segmented, linear mixed models were used to estimate the change in CVH over time. Among the 18,343 participants, 9,461 (52%) were female and 12,346 (67%) were White. The baseline mean (standard deviation) clinical CVH score was 6.9 (1.2) at an average age of 17.6 (8.1) years. Two inflection points were estimated: at 16.9 years (95% confidence interval: 16.4, 17.4) and at 37.2 years (95% confidence interval: 32.4, 41.9). Late adolescence and early middle age appear to be influential periods during which the loss of CVH accelerates.
The Use of DCE-MRI to Evaluate the Blood Supply to the Nipple-Areola Complex: A Study in 245 Asian Women
Authors: Wang Dawei , Xiong Shixuan , Ai Tao , Zeng Ning , Ren Yuping , Wu Min , Wu Yiping
Published: May 2021

Background

Understanding the main blood supply to the nipple-areola complex (NAC) is important for breast plastic surgery. However, previous reports have involved studies of cadavers and small sample sizes.

Objectives

This study aimed to identify and classify the in vivo blood supply to the NAC based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

Methods

DCE-MRI images of 393 breasts in 245 Asian women obtained from March 2012 to October 2019 were included retrospectively. Axial, coronal, and sagittal maximum-intensity projection images were evaluated to identify all vessels supplying the NAC. Blood supply to the NAC was classified into 9 anatomic zones: superomedial (Ia), medial (Ib), inferomedial (Ic), superolateral (IIa), lateral (IIb), inferolateral (IIc), central (III), inferior (IV), and superior (V).

Results

A total of 637 source vessels were identified in 393 breasts. Of the 393 breasts, 211 (53.7%) were supplied by a single zone, 132 (33.6%) by 2 zones, 38 (9.7%) by 3 zones, and 12 (3.1%) by 4 zones. Of the 637 vessels, 269 (42.2%) vessels were in zone Ia, 180 (28.3%) vessels were in zone IIa, and <10% of vessels were in the other zones. The number of NAC perfusion zones (P = 0.093) and the distribution of source vessels (P = 0.602) did not differ significantly between the left and right breasts.

Conclusions

DCE-MRI provides a clear indication of the blood supply to the NAC. Blood vessels from the superomedial and superolateral zones were the predominant sources of blood supplying the NAC.
powerEQTL: an R package and shiny application for sample size and power calculation of bulk tissue and single-cell eQTL analysis
Authors: Dong Xianjun , Li Xiaoqi , Chang Tzuu-Wang , Scherzer Clemens R , Weiss Scott T , Qiu Weiliang
Published: May 2021

Genome-wide association studies (GWAS) have revealed thousands of genetic loci for common diseases. One of the main challenges in the post-GWAS era is to understand the causality of the genetic variants. Expression quantitative trait locus (eQTL) analysis is an effective way to address this question by examining the relationship between gene expression and genetic variation in a sufficiently powered cohort. However, it is frequently a challenge to determine the sample size at which a variant with a specific allele frequency will be detected to associate with gene expression with sufficient power. This is a particularly difficult task for single-cell RNAseq studies. Therefore, a user-friendly tool to estimate statistical power for eQTL analyses in both bulk tissue and single-cell data is needed. Here, we presented an R package called powerEQTL with flexible functions to estimate power, minimal sample size or detectable minor allele frequency for both bulk tissue and single-cell eQTL analysis. A user-friendly, program-free web application is also provided, allowing users to calculate and visualize the parameters interactively.

Availability and implementation

The powerEQTL R package source code and online tutorial are freely available at CRAN: https://cran.r-project.org/web/packages/powerEQTL/. The R shiny application is publicly hosted at https://bwhbioinfo.shinyapps.io/powerEQTL/.

Supplementary information

Supplementary data are available at Bioinformatics online.
CURCUMINE REDUCES THE GROWTH OF COLORECTAL LIVER IMPLANTS IN RATS
Authors: Rodeño Casado M , Roa Esparza J , Iturrizaga S , Mar Medina C , García-Alonso I , Herrero de la Parte B
Published: May 2021

INTRODUCTION

Some plant-based antioxidants, such as curcumin, have shown anti-tumour properties against breast carcinomas and gliomas. The aim of this piece of work is to assess the anti-tumour effect of curcumin on CC531 colorectal cancer cells, both in vitro and in vivo.

MATERIAL AND METHODS

On CC531 cultures, cell viability was analysed, as well as cell migration capacity (wound healing test), 24, 48 and 72 hours after treatment with curcumin (15, 20, 25 or 30 µM). Additionally, in WAG/RijHsd rats bearing CC531-induced liver implants, total and individual liver lobe tumour volume was quantified in untreated and curcumin-treated animals (200 mg/kg/day, oral). Furthermore, serum enzyme measurements (GOT, GPT, glucose, bilirubin, etc.) were carried out to assess possible effects on liver function. ANOVA and t tests were used to analyse the effects of curcumine treatment.

RESULTS

In vitro studies showed curcumin's greatest effects 48h after application, when all tested doses reduced cell proliferation by more than 30% (0.443±0.06 vs. 0.319±0.04, 0.302±0.06, 0.274±0.06 and 0.243±0.03, respectively; p < 0.0001). At 72 hours, the highest doses of curcumin (25 and 30 µM) reduced cell viability to less than 50%. Wound healing test also showed that curcumine also inhibits migration capacity. In vivo, curcumin reduced by 5.6 fold the tumour volume of liver implants (7.98±1.45 vs 1.41±1.33; p < 0.0001); however, the volume of healthy liver tissue was higher in untreated animals (10.91±1.01 vs 8.80±1.06; p > 0.01).

CONCLUSIONS

Curcumin has shown an anti-tumour effect against liver implants from colorectal cancer, both in vitro and in vivo, in this experimental model.