bluuebunny/crossref_metadata_2025 huggingface dataset:
Pediatric Autoimmune Encephalitis: A Nationwide Study in Latvia
Authors: Pretkalnina D. , Grinvalde S. , Kalnina E.
Published: July 2024

Background Autoimmune encephalitis (AE) is the third most common encephalitis in children. Diagnosis can be challenging due to overlapping and diverse clinical presentations as well as various investigation results. This study aims to characterize the clinical, diagnostic features, as well as treatment and outcomes of AE in children and determine the incidence of pediatric AE in Latvia.

Methods The study was conducted at the Children's Clinical University Hospital in Riga. The study participants were patients under the age of 18 years diagnosed with AE from 2014 to 2022. Data regarding clinical characteristics, investigation findings, treatment strategy, and outcomes were retrospectively collected from the medical history data system.

Results We included 18 pediatric patients diagnosed with AE. The mean incidence of pediatric AE in Latvia was 0.56 per 100,000 children. Most patients (66.6%) had seronegative AE. In the seropositive group, the most common was anti-methyl-D-aspartate receptor AE, with two patients having other antibodies. The most prevalent clinical features were personality change, cognitive impairment, autonomic dysfunction, and movement disorders. The majority of patients (58.8%) received first-line treatment only. More than half (55.6%) of our AE patient group had long-term sequelae.

Conclusions Our study shows that the pediatric AE incidence in Latvia is similar to what has been previously reported in other studies. A relatively high proportion of seronegative AE was present in our cohort, indicating that awareness of possible misdiagnosis should be raised. Further research is needed to better understand the underlying mechanisms, characterize clinical features, and determine the treatment of choice in different situations to improve long-term outcomes.
Assessment of Aminoglycoside-Induced Hearing Loss Risk in the Perinatal Period
Authors: Thompson Whitney S. , Saba Leslie , Hasadsri Linda , Girard Sylvie , Schimmenti Lisa A. , Bendel-Stenzel Ellen M. , Wick Myra J. , Brumbaugh Jane E.
Published: July 2024

Objective This study aimed to determine the prevalence and heteroplasmy level(s) of MT-RNR1 variants m.1555A > G and m.1494C > T, which are associated with aminoglycoside-induced hearing loss, in a general perinatal population. This study also aimed to characterize the association of these variants and their heteroplasmy levels with hearing loss outcomes with and without aminoglycoside exposure.

Study Design Droplet digital polymerase chain reaction was performed on 479 maternal DNA samples from a general perinatal biobank at our institution to detect the presence and heteroplasmy levels of MT-RNR1 variants m.1555A > G and m.1494C > T. Testing of paired neonatal specimen(s) was planned for positive maternal tests. A retrospective chart review was performed to characterize the population, identify aminoglycoside exposures, and determine hearing outcomes.

Results All maternal samples tested negative for MT-RNR1 variants m.1555A > G and m.1494C > T. Maternal and neonatal subjects had high rates of aminoglycoside exposure (15.9 and 13.9%, respectively). No subjects with sensorineural or mixed hearing loss had documented aminoglycoside exposure.

Conclusion This study demonstrated that a larger sample size is needed to establish the prevalence of these variants as no subjects tested positive. Determination of variant prevalence in the neonatal population, association of variant heteroplasmy levels with hearing outcomes, and reliability of maternal testing as a surrogate for neonatal testing are important next steps toward universal prenatal or newborn screening.

Key Points
Beyond IR? Relationality, complementarity and entangled systems: response to Shih Chih-yu
Authors: Fierke K. M.
Published: July 2024

This contribution revisits Shih's mission of relational IR and the Chinese relational school from the perspective of the parallel between quantum physics and ancient Asian philosophies, such as Buddhism and Daoism, asking questions about the significance of relational IR as a contradiction or complementarity, the nature of relational systems, and the role of conversation and translation in an unfolding world. It concludes with a reflection on time, memory and emotion as it relates to a past of empire.
Relation between attitudes towards pornography consumption, peer sexual behaviors and attitudes towards premarital sex among the college students in Guangdong province, China
Authors: Peng Yangzhi , Zheng Yongru
Published: July 2024

Limited research exists on college students’ attitudes towards premarital sex in China, despite its increasing prevalence among youth. This study examines the correlation between attitudes towards pornography consumption, peer sexual behaviors, and college students’ attitudes towards premarital sex in Guangdong province, China. Using convenient and snowball sampling, 326 participants completed a questionnaire. Results reveal significant correlations between attitudes towards pornography consumption, peer sexual behaviors, and attitudes towards premarital sex. The study discusses implications for practice and policy. These findings offer practical insights for future research on love and marriage in Chinese society.
Measurement error in hydrostatic leveling system due to temperature effect and their reduction method
Authors: Xu Jian , Tong Zhi-Feng , Xu Yan-Zhao , Dai Hong-Liang
Published: July 2024

Temperature is a crucial factor influencing the accuracy of the hydrostatic leveling system (HLS), necessitating a temperature compensation test for HLS. This paper investigates HLS temperature compensation through theoretical correction and experimental verification. The influence of temperature on the accuracy of hydrostatic level products is determined through temperature tests on 34 hydrostatic level products. The optimal temperature compensation formula is derived using the non-linear curve fitting method. The HLS is enhanced with a temperature compensation algorithm and temperature sensor, resulting in a new, high-precision, and high-stability hydrostatic leveling product with temperature compensation. Experimental findings reveal that the stability of the improved hydrostatic leveling product exceeds 30% compared to products on the market and surpasses 70% compared to the original products.
A rigorous theory on electromagnetic diffraction by a planar aperture in a perfectly conducting screen
Authors: Liang Ying , Zhang Hai
Published: July 2024

In this paper, we revisit the classic problem of diffraction of electromagnetic waves by an aperture in a perfectly conducting plane. We formulate the diffraction problem using a boundary integral equation that is defined on the aperture using Dyadic Green’s function. This integral equation turns out to align with the one derived by Bethe using fictitious magnetic charges and currents. We then investigate the boundary integral equation using a saddle point formulation and establish the well-posedness of the boundary integral equation, including the existence and uniqueness of the solution in an appropriately defined Sobolev space.
Temperature-reducing shocks in optically thin radiative MHD—Analytical and numerical results
Authors: Snow B.
Published: July 2024

Shocks are often invoked as heating mechanisms in astrophysical systems, with both adiabatic compression and dissipative heating that leading to the increase in temperature. While shocks are reasonably well understood for ideal magnetohydrodynamic (MHD) systems, in many astrophysical plasmas, radiation is an important phenomena, which can allow energy to leave the system. As such, energy becomes non-conservative, which can fundamentally change the behavior of shocks. The energy emitted through optically thin radiation post-shock can exceed the thermal energy increase, resulting in shocks that reduce the temperature of the medium, i.e., cooling shocks that have a net decrease in temperature across the interface. In this paper, semi-analytical solutions for radiative shocks are derived to demonstrate that both cooling (temperature decreasing) and heating (temperature increasing) shock solutions are possible across the whole temperature range in optically thin radiative MHD. Numerical simulations of magnetic reconnection for solar-like temperatures and plasma-β with optically thin radiative losses also yield both heating and cooling shocks in roughly equal abundances. The detected cooling shocks feature a significantly lower pressure jump across the shock than their heating counterparts. The compression at the shock front leads to locally enhanced radiative losses, resulting in significant cooling within a few grid cells in the upstream and downstream directions. The presence of temperature-reducing (cooling) shocks is critical in determining the thermal evolution, and heating or cooling, across a wealth of radiative astrophysical plasmas including magnetic reconnection in the solar corona.
Cost effective synthesis of sulfur and nitrogen co-doped graphene aerogel and application in binder free supercapacitor
Authors: Muhiuddin Mohammad , Khan Aliullah Zaifullah , Devi Naorem Aruna , Bharadishettar Naveen , Meti Sunil , Siddique Abu Bakar , Bhat K. Udaya , Akhtar Waseem , Rahman Mohammad Rizwanur
Published: July 2024

Incorporating heteroatoms into graphene lattice results in enhanced electrical conductivity and electrochemically active sites and has significant importance in developing high-performance supercapacitors. In this study, sulfur and nitrogen co-doped graphene aerogel is synthesized via hydrothermal technique followed by a simple but effective freeze-thawing and ambient pressure drying process (referred to as SN-GA). The process requires low-cost raw materials and cost-effective equipment without the utilization of any special instrument that operates at ultra-low temperatures, under high pressure, or vacuum environment. Ammonium sulfate [(NH4)2SO4] and ethylenediamine are used as a source of sulfur and nitrogen and as a reducing agent. (NH4)2SO4 with different molarities (0, 12, 24, and 36 mM) are used to synthesize four different aerogel samples marked as GA, SN-GA1, SN-GA2, and SN-GA3. The electrode is prepared using an SN-GA2 sample, exhibiting an outstanding specific capacitance of 244 F g−1 at an applied current density of 1 A g−1 with almost 98.5% Coulomb efficiency. Furthermore, based on the SN-GA2 sample, the symmetrical supercapacitor is fabricated, displaying an energy density of 18.14 Wh kg−1 at a power density of 498.4 W kg−1. Hence, SN-GA2 renders a promising material for supercapacitor applications.
A gas chromatography system for measuring carbonaceous gases released at high-pressure and high-temperature conditions
Authors: Wu Sensen , Tao Renbiao , Chen Bin , Dong Hongliang , Xiao Zhijian , Zhang Baohua , Hu Qingyang
Published: July 2024

Carbonates or carbon-bearing materials may release gases under high pressure and high temperature (HP–HT) conditions. Characterizing the species and quantifying the volumes of these carbonaceous gases are critical for understanding carbon chemistry. However, the volatile nature of carbonaceous gas poses technical challenges in their collection, speciation, and quantification during HP–HT experiments. To address these challenges, we have developed a system that integrates sample collection, gas transportation, chemical conversion, and measurement of carbonaceous gases trapped within the large volume press capsules. The system comprises a capsule-crushing device for thorough sample pulverization, a mechanizer coupled with a flame ionization detector, a gas-sealing and transport interface, and gas chromatography for detection. To evaluate the system’s capabilities, we quantified the gas volumes released from encapsulated kerogen quenched from 1.9 GPa to 873, 973, and 1073 K. The collected gas chromatography signals were compared to those obtained from standard mixed-gases. The volumes of CO2, CH4, and C2H6 in the samples were successfully derived from the signal peak area through calibration. The relative standard deviation value of two runs at 3 GPa and 1073 K is 1.956%, suggesting good reproducibility. Our system thus provides a robust solution for investigating carbon chemistry under HP–HT conditions.
Toward a numerically efficient description of bulk-solvated anionic states
Authors: Kiataki Matheus B. , Coutinho Kaline , Varella Márcio T. do N.
Published: July 2024

We investigate the vertical electron attachment energy (VAE) of 1-methyl-4-nitroimidazole, a model radiosensitizer, employing quantum mechanics/molecular mechanics (QM/MM) and QM/polarized continuum (QM/PCM) solvation models. We considered the solvent-excluded surface (QM/PCM-SES) and Van der Waals (QM/PCM-VDW) cavities within the PCM framework, the electrostatic embedding QM/MM (EE-QM/MM) model, and the self-consistent sequential QM/MM polarizable electrostatic embedding (scPEE-S-QM/MM) model. Due to slow VAE convergence concerning the number of QM solvent molecules, full QM calculations prove inefficient. Ensemble averages in these calculations do not align with VAEs computed for the representative solute–solvent configuration. QM/MM and QM/PCM calculations show agreement with each other for sufficiently large QM regions, although the QM/PCM-VDW model exhibits artifacts linked to the cavity. QM/MM models demonstrate good agreement between ensemble averages and VAEs calculated with the representative configuration. Notably, the VAE computed with the scPEE-S-QM/MM model achieves faster convergence concerning the number of QM water molecules compared to the EE-QM/MM model, attributed to enhanced efficiency from MM charge polarization in the scPEE-S-QM/MM approach. This emphasizes the importance of QM/classical models with accurate solute–solvent and solvent–solvent mutual polarization for obtaining converged VAEs at a reasonable computational cost. The full-QM approach is very inefficient, while the microsolvation model is inaccurate. Computational savings in QM/MM models result from electrostatic embedding and the representative configuration, with the scPEE-S-QM/MM approach emerging as an efficient tool for describing bulk-solvated anions within the QM/MM framework. Its potential extends to improving transient anion state descriptions in biomolecules and radiosensitizers, especially given the frequent employment of microsolvation models.
A Gaussian process based surrogate approach for the optimization of cylindrical targets
Authors: Gammel William P. , Sauppe Joshua Paul , Bradley Paul
Published: July 2024

Simulating direct-drive inertial confinement experiments presents significant computational challenges, both due to the complexity of the codes required for such simulations and the substantial computational expense associated with target design studies. Machine learning models, and in particular, surrogate models, offer a solution by replacing simulation results with a simplified approximation. In this study, we apply surrogate modeling and optimization techniques that are well established in the existing literature to one-dimensional simulation data of a new cylindrical target design containing deuterium–tritium fuel. These models predict yields without the need for expensive simulations. We find that Bayesian optimization with Gaussian process surrogates enhances sampling efficiency in low-dimensional design spaces but becomes less efficient as dimensionality increases. Nonetheless, optimization routines within two-dimensional and five-dimensional design spaces can identify designs that maximize yield, while also aligning with established physical intuition. Optimization routines, which ignore constraints on hydrodynamic instability growth, are shown to lead to unstable designs in 2D, resulting in yield loss. However, routines that utilize 1D simulations and impose constraints on the in-flight aspect ratio converge on novel cylindrical target designs that are stable against hydrodynamic instability growth in 2D and achieve high yield.
Direct mechanistic connection between acoustic signals and melt pool morphology during laser powder bed fusion
Authors: Sun Yuchen , Gorgannejad Sanam , Martin Aiden , Nicolino Jenny , Strantza Maria , Forien Jean-Baptiste , Thampy Vivek , Liu Sen , Quan Peiyu , Tassone Christopher J. , Matthews Manyalibo J. , Calta Nicholas P.
Published: July 2024

Various nondestructive diagnostic techniques have been proposed for in situ process monitoring of laser powder bed fusion (LPBF), including melt pool pyrometry, whole-layer optical imaging, acoustic emission, atomic emission spectroscopy, high speed melt pool imaging, and thermionic emission. Correlations between these in situ monitoring signals and defect formation have been demonstrated with acoustic signals having been shown to predict pore formation with especially high confidence in recent machine learning studies. In this work, time-resolved acoustic data are collected in both the conduction and keyhole welding regimes of LPBF-processed Ti-6Al-4V alloy. A non-dimensionalized Strouhal number analysis, used in whistle aeroacoustics, is applied to demonstrate that the acoustic signals recorded in the keyhole regimes can be directly associated with the vapor depression morphology. This mechanistic understanding developed from whistle aeroacoustics shows that acoustic monitoring during the LPBF process can provide a direct probe into the vapor depression dynamics and defect occurrence, especially in the keyhole regimes relevant to printing and defect formation.
Combined effects of the roughness, aperture, and fractal features on the equivalent permeability and nonlinear flow behavior of rock fracture networks
Authors: Zhao Mingkai , Kong Desen , Teng Sen , Shi Jian
Published: July 2024

The hydraulic properties of a fractured rock mass are largely controlled by connected fracture networks. A thorough understanding of the physical flow processes in fracture networks is essential for assessing the transport capacity of the rock mass. However, the fracture surface roughness morphology, fracture distribution characteristics, and fluid flow regimes strongly influence the flow capacity of a fracture network. To this end, the rough topographic characteristics of fracture surfaces were quantified using fractal theory, and then the effective permeability model and nonlinear seepage effect assessment model of the rough fracture network for different flow regimes were developed based on the possible occurrence of laminar and turbulent flows in a single fracture. Finally, the influences of the geometric parameters of the fracture network on the effective permeability and nonlinear flow characteristics were analyzed. The results show that the prediction results of the proposed models are in good agreement with the field test data and can effectively reveal the seepage influence mechanisms under different flow regimes. Additionally, the results show that the effective permeability is closely related to the fractal dimension, relative roughness, aperture scale, distribution characteristics, and hydraulic gradient of the fractures. The nonlinear behavior of fluid flow significantly reduces the effective permeability of the rock mass. The proposed models can provide a reference for evaluating the transport capacity of rock masses under different fracture distributions and flow regimes.
Large magnetocaloric refrigeration performance near room temperature in monolayer transition metal dihalides
Authors: Xie Weifeng , Xu Xiong , Li Fangbiao , Zhai Guangwei , Yue Yunliang , Li Min , Wang Hui
Published: July 2024

Magnetocaloric effect (MCE) exhibits highly efficient and ecological cooling abilities for solid-state refrigeration in contrast to traditional vapor-compression refrigeration. Successive emerging two-dimensional (2D) magnetic materials provide a fertile platform for exploring low-dimensional MCE systems. Here, we focus on a series of 2D transition metal dihalides MX2 (M = Fe, Ru, Os; X = Cl, Br) to explore the maximum isothermal magnetic entropy change (−ΔSmagmax) and adiabatic temperature change (ΔTadmax) under external magnetic field. It is found that FeCl2, FeBr2, and RuCl2 have intrinsically sizable −ΔSmagmax, ΔTadmax, and high thermal conductivity near room temperature, demonstrating superior comprehensive refrigeration performance in comparison with other 2D magnets. It is revealed that strong nearest-neighbor ferromagnetic exchange interaction plays a decisive role in −ΔSmagmax, and the high lattice thermal conductivities of FeCl2 and RuCl2 are attributed to the longer phonon lifetime and larger group velocity of low-frequency acoustic branch. Moreover, moderate strain and carriers doping are able to effectively regulate Curie temperature and magnetocrystalline anisotropy energy and correspondingly enhance −ΔSmagmax. The present work provides important insights for the exploration of 2D magnets for magnetocaloric refrigeration near room temperature.
Embossed x-ray computed tomography utilizing pixel-shifted dual-energy subtraction
Authors: Ito Kazuki , Sato Eiichi , Oda Yasuyuki , Moriyama Hodaka , Hagiwara Osahiko , Enomoto Toshiyuki , Yoshida Sohei , Watanabe Manabu
Published: July 2024

To observe fine blood vessels as uneven tomographic images at a high contrast, we performed tentative experiments on embossed x-ray computed tomography (CT). We constructed a cone-beam CT scanner and carried out dual-energy CT with tube voltages of 60 and 100 kV. X-ray photons penetrating through an object were detected using an indirect-conversion flat panel detector, and radiograms were produced and sent to a personal computer to reconstruct tomograms. Embossed CT was performed using pixel-shifted dual-energy subtraction, and blood vessels filled with Gd medium were observed as uneven images at high contrast and spatial resolutions. Using 1.4-time magnification imaging in combination with a 0.1-mm-focus x-ray tube, the diameter of the object visible on the embossed CT was below 100 μm.
High-resolution Li depth profiling in a thin-film all-solid-state battery using TOF-ERDA
Authors: Majima T. , Ogura Y. , Hasegawa C. , Nakamizo S. , Tsuchiya B. , Amezawa K. , Iriyama Y. , Yasuda K.
Published: July 2024

A quantitative understanding of the Li distribution inside all-solid-state Li-ion batteries is important for improving the performance of batteries. We constructed a time-of-flight (TOF) elastic recoil detection analysis (ERDA) system for operando measurements of thin-film Li-ion batteries. The TOF-ERDA measurement provides elementally resolved spectra with a depth resolution much higher than that of conventional stopper-foil ERDA. The Li depth profiles in a cathode film and solid electrolyte were obtained quantitatively to a depth of 100 nm using a 9-MeV Cu ion beam with reflection geometry. In this study, we conducted TOF-ERDA for a thin-film battery having a cathode made from LiCoO2, an oxide-based solid electrolyte [lithium aluminum titanium phosphate (LATP)], and an anode made from Fe2(MoO4)3 to demonstrate the ability of the measurement system and reveal the Li distribution near the interface with improved resolution. The depth resolution at the interface (30 nm from the surface) was estimated to be 12–14 nm. We quantitatively obtained the Li density in the LiCoO2 cathode and the variation in the Li distribution around the LiCoO2/LATP interface and inside the LATP electrolyte upon charging/discharging. TOF-ERDA is thus a powerful tool for the high-resolution quantitative depth analysis of Li in thin-film batteries in operando.
Temporal consistency loss for physics-informed neural networks
Authors: Thakur Sukirt , Raissi Maziar , Mitra Harsa , Ardekani Arezoo M.
Published: July 2024

Physics-informed neural networks (PINNs) have been widely used to solve partial differential equations (PDEs) in a forward and inverse manner using neural networks. However, balancing individual loss terms can be challenging, mainly when training these networks for stiff PDEs and scenarios requiring enforcement of numerous constraints. Even though statistical methods can be applied to assign relative weights to the regression loss for data, assigning relative weights to equation-based loss terms remains a formidable task. This paper proposes a method for assigning relative weights to the mean squared loss terms in the objective function used to train PINNs. Due to the presence of temporal gradients in the governing equation, the physics-informed loss can be recast using numerical integration through backward Euler discretization. The physics-uninformed and physics-informed networks should yield identical predictions when assessed at corresponding spatiotemporal positions. We refer to this consistency as “temporal consistency.” This approach introduces a unique method for training physics-informed neural networks (PINNs), redefining the loss function to allow for assigning relative weights with statistical properties of the observed data. In this work, we consider the two- and three-dimensional Navier–Stokes equations and determine the kinematic viscosity using the spatiotemporal data on the velocity and pressure fields. We consider numerical datasets to test our method. We test the sensitivity of our method to the timestep size, the number of timesteps, noise in the data, and spatial resolution. Finally, we use the velocity field obtained using particle image velocimetry experiments to generate a reference pressure field and test our framework using the velocity and pressure fields.
Trapping of particles diffusing in cylindrical cavity of arbitrary length and radius by two small absorbing disks on the cavity side wall: Narrow escape theory and beyond
Authors: Dagdug Leonardo , Berezhkovskii Alexander M.
Published: July 2024

Narrow escape theory deals with the first passage of a particle diffusing in a cavity with small circular windows on the cavity wall to one of the windows. Assuming that (i) the cavity has no size anisotropy and (ii) all windows are sufficiently far away from each other, the theory provides an analytical expression for the particle mean first-passage time (MFPT) to one of the windows. This expression shows that the MFPT depends on the only global parameter of the cavity, its volume, independent of the cavity shape, and is inversely proportional to the product of the particle diffusivity and the sum of the window radii. Amazing simplicity and universality of this result raises the question of the range of its applicability. To shed some light on this issue, we study the narrow escape problem in a cylindrical cavity of arbitrary size anisotropy with two small windows arbitrarily located on the cavity side wall. We derive an approximate analytical solution for the MFPT, which smoothly goes from the conventional narrow escape solution in an isotropic cavity when the windows are sufficiently far away from each other to a qualitatively different solution in a long cylindrical cavity (the cavity length significantly exceeds its radius). Our solution demonstrates the mutual influence of the windows on the MFPT and shows how it depends on the inter-window distance. A key step in finding the solution is an approximate replacement of the initial three-dimensional problem by an equivalent one-dimensional one, where the particle diffuses along the cavity axis and the small absorbing windows are modeled by delta-function sinks. Brownian dynamics simulations are used to establish the range of applicability of our approximate approach and to learn what it means that the two windows are far away from each other.
High-efficiency electroluminescence devices containing Si nanocrystals/SiC multilayers via improved carrier injection and recombination process
Authors: Sun Teng , Wang Yuhao , Han Junnan , Chen Jiaming , Zhu Ting , Li Dongke , Li Wei , Xu Jun , Chen Kunji
Published: July 2024

Realizing high efficiency of all Si-based light-emitting devices is currently one of interesting issues in order to develop monolithic opto-electronic integration on chips. Here, we report an electroluminescence device based on phosphorus (P)-doped silicon nanocrystals (Si NCs)/silicon carbide (SiC) multilayers by modulating carrier injection and recombination process. The p+-Si substrate is used instead of p-Si substrate for facilitating the hole injection into Si NCs. Additionally, the influences of annealing temperature on the device performance have been studied, and the optimized annealing temperature is achieved by balancing the crystallinity, defect state density, and recombination process.
Effect of diversion angle and vanes' skew angle on the hydro-morpho-dynamics of mobile-bed open-channel bifurcations controlled by submerged vane-fields
Authors: Gumgum Firat , Cardoso António Heleno
Published: July 2024

The aim of this study was to characterize the impact of the diversion angle on the bed morphology, flow structure, and sediment fluxes at mobile-bed, open channel bifurcations, both uncontrolled and controlled with a submerged vane-field. The study also addressed the effects of the skew angle of the vanes and of the mobility of the diversion channel bed. For these purposes, 24 experiments were carried out with the diversion angles θ = {30°, 45°, 60°, 75°, 90°, 120°}. The recirculation zones in the diversion channel were classified according to their aspect ratios and two governing secondary circulations were identified inside these zones. In the presence of a vane-field, a strong vortex developed in the main channel all along the vane-field until past the diversion entrance. This vortex incorporated the main channel leg of the unique two-leg vortex that is otherwise identified in the absence of vanes at the downstream diversion corner. An independent diversion channel vortex replaced the diversion channel leg of the two-leg vortex. The best desilting efficiency was achieved for the diversion angle θ = 30°, regardless of the presence or the absence of vanes and the mobility of the diversion channel bed. In fully mobile-bed bifurcations, complete desilting was achieved for θ = 30° and α = 45°. This was also achieved for any of the tested skew angles, α = {15°, 45°}, when the diversion channel bed was rigid.
On a Mott formalism for modeling oxide thin-film transistors
Authors: Yi Guangzheng , Li Yuan , Cai Kunlin , Yu Jun , Nathan Arokia
Published: July 2024

We report on a device model for thin-film transistors (TFTs) in the framework of Mott's trap-and-release transport theory for disordered semiconductors. The model features a so-called Mott function that is demonstrated to be powerful for analytically deriving the terminal characteristics and other critical parameters of TFTs, including threshold voltage, subthreshold swing, and field-effect mobility. The model is validated by way of application to an amorphous InGaZnO (IGZO)-based TFT, for which good agreement between the analytical and experimental data are obtained. This study offers a simple yet powerful formalism for effective parameter characterization and extraction for oxide and other related TFTs, including those from the organic materials family.
LaFeSi–LaFe13−xSix composites: Modulating magnetic and magnetocaloric properties through inherent stress manipulation
Authors: Del Rose Tyler J. , Chouhan Rajiv K. , Doyle Andrew , Pathak Arjun K. , Mudryk Yaroslav
Published: July 2024

We examine structural and magnetic properties of a series of La–Fe–Si alloys in the region of concentrations where they naturally form two-phase LaFeSi–LaFe13−xSix composites with variable content and connectivity of LaFe13−xSix grains distributed within the LaFeSi matrix. Theoretical calculations confirm that the LaFeSi constituent is magnetically and structurally inert below room temperature and at pressures between −10 and 10 GPa. The LaFe13−xSix constituent, on the other hand, is magnetically and structurally active: it exhibits first-order magnetostructural transformations that, in addition to xSi, can be controlled with temperature, magnetic field, and pressure. In composites where the concentration of the inactive constituent is ∼70 wt. % or greater, the standard, single-step, LaFe13−xSix first-order phase transformation proceeds in two steps separated by over 30 K in a zero magnetic field. Increasing the magnetic field recouples the two steps and restores the single-step phase transformation pathway. We analyze the roles of stresses caused by both thermal expansion mismatch and the first-order magnetic phase transition in LaFe13−xSix to rationalize the observed physical behaviors that emerge as the temperature or/and magnetic field vary.
Enhanced optical responsivity in photothermoelectric effect of SnSe–SnSe2 composite at near-infrared band
Authors: Jiang Hong-Tao , Tian Hao , Sun Su-Tao , Cao Lin , Yin Cheng-Hao , Zhou Xiao-Li , Lv Yang-Yang , Zhou Jian , Yao Shu-Hua , Chen Y. B. , Chen Yan-Feng
Published: July 2024

We experimentally demonstrated that composites, being effective in optimizing the thermoelectric performance, can also enhance photothermoelectric effects in this work. In detail, we employed an alternating-growth in chemical-vapor-transport to grow the SnSe–SnSe2 composite crystals. The photo-responsivities of SnSe–SnSe2 (atomic-weight-ratio as 44%–56%) composite are comparable to SnSe crystals in the visible band (444 and 532 nm). However, the responsivities of SnSe–SnSe2 have remarkable 27.3% enhancement than those of SnSe crystal at the near-infrared band (1310 and 1550 nm). Supported by optical spectroscopy and theoretical electronic band structure, the enhanced optical responsivity of SnSe–SnSe2 composites is due to the formation of P–N junctions at interfaces between SnSe and SnSe2, leading to more optical transition channels and corresponding optical absorptions in near-infrared band. Our work verifies that hetero-junction formed among constituent compounds in composites is effective in optimizing the photothermoelectric response of thermoelectric materials in certain electromagnetic bands, paving the way to develop photoelectric detection devices.
Frequency-domain quadrupole correction for the permeable-surface Ffowcs Williams and Hawkings integration
Authors: Zhou Zhiteng , Liu Yi , Wang Shizhao
Published: July 2024

The permeable-surface Ffowcs Williams and Hawkings (FW–H) integration for computing the far-field sound has the advantage of encapsulating the sources and nonlinear propagation inside the integral surface. However, it suffers from spurious sound when the volume integral for quadrupole term outside the permeable surface is conventionally ignored. The spurious sound is often suppressed by using two distinct approaches, which modifies the FW–H integration and acoustic variables/sources, respectively. This work clarifies the connection between the two approaches by analyzing the integral of the quadrupole sources. We show that the modification of the acoustic sources can be reformulated as a modification of the FW–H integration, which means that the two distinct approaches are interconvertible. A new quadrupole correction model for the FW–H integration is proposed by delicately modifying the acoustic sources. The modified acoustic sources consist of the filtered Lighthill stress tensor, where a convection operator is used to filter out the acoustically inefficient components. The proposed quadrupole correction model is consistent with the previous work on the modification of the FW–H integration under special conditions with the uniform convection velocity. The proposed model is validated by computing the sound pressure generated by laminar and turbulent flows over bluff bodies. It is found that the sensitivity of the acoustic pressure to the FW–H surface's position is suppressed and the accuracy of the predicted sound is improved. The results suggest that the modification of acoustic variables/sources can be a powerful method to construct new quadrupole correction models for the permeable FW–H integration.
Numerical simulation of plume–surface interaction and lunar dust dispersion during lunar landing using four engines
Authors: Gao Da , Cai Guobiao , Zhang Huanying , Zhang Baiyi , Liu Lihui , He Bijiao
Published: July 2024

As the lander approaches the lunar surface, the engine plumes impinge on the lunar regolith and entrain lunar dust from the surface. This plume–surface interaction and the resulting dispersion of lunar dust form a multi-physics, multi-scale problem, which becomes even more complex under multi-engine conditions. This study employed the direct simulation Monte Carlo method to simulate the plume–surface interaction flow field of a four-engine lunar lander at various landing altitudes and lunar surface angles. Flow characteristics were analyzed, and the impact of the plume and backflow on the lander was assessed. Subsequently, lunar dust simulation was conducted using the plume field as a basis. The study determined the spatial distribution of particles with different diameters at various landing altitudes and surface angles, as well as their impact velocities on the lander. Furthermore, taking into account the variations in the lander's altitude and attitude, a dynamic simulation of lunar dust during the landing process was conducted. This process resulted in the dynamic distribution of lunar dust during landing, laying the groundwork for real-time simulation of lunar dust distribution and reliable visualization during landing simulations. These findings are valuable for assessing and mitigating the hazards posed by lunar dust.
The impact of left atrial morphology on thrombosis risk in atrial fibrillation
Authors: Wang Yan , Xu Buyun , Luo Kun , Fan Jianren , Xiang Meixiang
Published: July 2024

Atrial fibrillation (AF) is an arrhythmia disease that can disrupt the movement of the left atrium (LA), which will facilitate thromboembolism in LA and further exacerbate the stroke risk. The left atrial appendage (LAA) is a vital site for thrombus formation. The morphology of the LAA is believed to have a profound effect on thrombosis. However, due to the limitation of observation and monitoring methods, the mechanism of this effect is still unrevealed. Virchow's triad is a theory of thrombogenic mechanisms, stating that endothelial injury, blood hypercoagulability, and blood stasis are the three main factors involved in thrombus formation. In this study, we conducted personalized simulation analyses for 12 AF patients and discussed simulation results from the perspective of Virchow's triad. The simulation results indicate the effectiveness of Virchow's triad in elucidating the thrombosis mechanism within the LAA. The LAA is more prone to thrombosis than the other region of LA, because of the lower blood flow velocity and significantly higher endothelial cell activation potential values there, which indicates a higher risk of blood stasis and endothelial injury, respectively. Furthermore, a comprehensive score is proposed to assess the performance of Virchow's triad in the LAA. The morphology of LA has a significant influence on the performance of the three factors in Virchow's triad. Hence, for a quickly assessment of LAA thrombosis risk in AF patients through the lens of Virchow's triad, we need a more refined shape scoring system that can better reflect patient-specific morphological features of the entire LA.
Reynolds number effect of a vortex ring impinging on a concave hemi-cylindrical shell
Authors: Zhang Liangquan , Li Guangtao , Chen Wen-Li , Gao Donglai
Published: July 2024

Experimental investigations were conducted on a single vortex ring impinging on a concave hemi-cylindrical shell with Dm/De = 2 at different Reynolds numbers. Vortex rings with five different Reynolds numbers were generated for experimental studies, i.e., Re = 750, 1500, 3000, 5000, and 7000. The planar laser-induced fluorescence visualizations and two-dimensional particle image velocimetry measurements were used in the experiment. The vorticity field based on the Eulerian framework and the finite-time Lyapunov exponent (FTLE) field based on the Lagrangian framework were used to identify the dynamic processes of vortex rings, respectively. The results show that as the vortex rings impinge on concave surfaces from Re = 750 to Re = 7000, the extension of the main vortex ring in the straight-edged direction is larger than that in the concave direction, and the instability of the vortex ring is promoted. While the Reynolds number is increasing, the vortex ring deformation becomes larger, and the overall vortex ring cross section becomes smaller, leading to a larger attenuation of the vortex ring rotation. Calculations performed by the FTLE field were used to derive the Lagrangian coherent structure to analyze the boundaries of the vortex ring motion process, clearly observe the shape of the secondary vortex connecting segments, and verify the speculation by the vortex ring trajectory identification results. Finally, a dynamic model of vortex rings impinging a concave surface was proposed, and the inference of the experimental process was explained by the model.
Glycyrrhetinic acid interaction with solvated and free electrons studied by the CIDNP and dissociative electron attachment techniques
Authors: Polyakov Nikolay E. , Mastova Anna V. , Kruppa Alexander I. , Asfandiarov Nail L. , Pshenichnyuk Stanislav A.
Published: July 2024

Electron transfer plays a crucial role in living systems, including the generation of reactive oxygen species (ROS). Oxygen acts as the terminal electron acceptor in the respiratory chains of aerobic organisms as well as in some photoinduced processes followed by the formation of ROS. This is why the participation of exogenous antioxidants in electron transfer processes in living systems is of particular interest. In the present study, using chemically induced dynamic nuclear polarization (CIDNP) and dissociative electron attachment (DEA) techniques, we have elucidated the affinity of solvated and free electrons to glycyrrhetinic acid (GA)—the aglicon of glycyrrhizin (the main active component of Licorice root). CIDNP is a powerful instrument to study the mechanisms of electron transfer reactions in solution, but the DEA technique shows its effectiveness in gas phase processes. For CIDNP experiments, the photoionization of the dianion of 5-sulfosalicylic acid (HSSA2−) was used as a model reaction of solvated electron generation. DEA experiments testify that GA molecules are even better electron acceptors than molecular oxygen, at least under gas-phase conditions. In addition, the effect of the solvent on the energetics of the reactants is discussed.
Mutual synergistic regulation of chloride anion and cesium cation binding using a new designed macrocyclic multi-functional sites receptor: A case of DFT computational prediction
Authors: Yuan Kun , Yao Qingqing , Liu Yanzhi
Published: July 2024

The mutual synergistic regulation of the multi-functional sites on a single receptor molecule for ion-binding/recognition is vital for the new receptor design and needs to be well explored from experiment and theory. In this work, a new macrocyclic ion receptor (BEBUR) with three functional zones, including two ether holes and one biurea groups, is designed expecting to mutually enhance the ion-binding performance. The binding behaviors of BEBUR mainly for Cl− and Cs+ are deeply investigated by using density functional theoretical calculations. It is found that Cl−/Cs+ binding can be mutually enhanced and synergistically regulated via corresponding conformational changes of the receptor, well reflecting an electrical complementary matching and mutual reinforcement effect. Moreover, solvent effect calculations indicate that BEBUR may be an excellent candidate structure for Cl−-binding with the enhancement of counter ion (Cs+) in water and toluene. In addition, visualization of intermolecular noncovalent interaction is used for analysis on the nature of the binding interactions between receptor and ions.
A unified macroscopic equation for creeping, inertial, transitional, and turbulent fluid flows through porous media
Authors: Arthur J. K.
Published: July 2024

Over the course of several decades, numerous model equations of the macroscopic fluid flow through porous media have been proposed. The application of such equations is, however, often complicated due to the requirement of variant specifications of parameters and empirical factors for different flow regimes. It is, therefore, necessary and desirable to have a unified fundamental equation that is capable of predicting porous media flows for the entire spectrum of flow regimes that are practically encountered. This work aims to fulfill that requirement. With the aid of a hypothesis-based analysis, finite-element simulations, and published experimental data, a new macroscopic transport equation has been proposed to predict statistically stationary single-phase incompressible flows through a non-deformable stationary porous medium. The new model may be written as a drag law associated with a dimensionless resistance parameter that is a function of the porous medium geometry and the flow forces. Though complex, this resistance parameter may be modeled as a power function in terms of three predictable parameters. Overall, the proposed transport equation has been found to be a more extensive form of other key models in existence. Using approximately 6000 analytical, numerical, and experimental data points, the equation has been validated as an excellent model for creeping, inertial, transitional, and turbulent porous media flows. The results show that the proposed equation is applicable to simple and complex porous media of 30%–90% porosity. Moreover, a dimensionless group in terms of the equation's resistance parameter has been established as useful for scaling.
Binary phase behavior of select organosulfur compounds in supercritical carbon dioxide: A Monte Carlo molecular simulation study
Authors: DeMartinis Derek K. , Stubbs John M.
Published: July 2024

Pressure–composition binary phase diagrams were determined for methanethiol, dimethyl sulfide, thiophene, benzothiophene, or dibenzothiophene with carbon dioxide at temperatures from 363 to 453 K and pressures from 2 to 20 MPa. Utilizing Gibbs ensemble Monte Carlo molecular simulation, phase coexistence compositions were determined, along with the impact of 4% water cosolvent on select results. Solution structure as a function of pressure and temperature is characterized via radial distribution functions. Comparison to available experimental composition data gives overall mean absolute percentage deviations of 2.2% for thiophene, 37% for methanethiol, and 99% for benzothiophene. Solubilities in a CO2-rich phase are calculated to be sufficient to allow extraction and detection of the compounds studied here via supercritical fluid chromatography and mass spectrometry as a possible analysis approach for future Mars rover missions.
Voltage mapping in subcellular nanodomains using electro-diffusion modeling
Authors: Paquin-Lefebvre Frédéric , Holcman David
Published: July 2024

Voltage distribution in sub-cellular micro-domains such as neuronal synapses, small protrusions, or dendritic spines regulates the opening and closing of ionic channels, energy production, and thus, cellular homeostasis and excitability. Yet how voltage changes at such a small scale in vivo remains challenging due to the experimental diffraction limit, large signal fluctuations, and the still limited resolution of fast voltage indicators. Here, we study the voltage distribution in nano-compartments using a computational approach based on the Poisson–Nernst–Planck equations for the electro-diffusion motion of ions, where inward and outward fluxes are generated between channels. We report a current–voltage (I–V) logarithmic relationship generalizing Nernst law that reveals how the local membrane curvature modulates the voltage. We further find that an influx current penetrating a cellular electrolyte can lead to perturbations from tens to hundreds of nanometers deep, depending on the local channel organization. Finally, we show that the neck resistance of dendritic spines can be completely shunted by the transporters located on the head boundary, facilitating ionic flow. To conclude, we propose that voltage is regulated at a subcellular level by channel organization, membrane curvature, and narrow passages.