bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of quantum effects on the brittle–ductile transition in cryocrystals
Authors: Leont’eva A. V. , Romanusha V. A. , Feľdman É. P.
Published: December 2024

We have studied the properties of ductility, strength, and the brittle–ductile transition (BDT) in inert Ne, Ar, Kr, and Xe cryocrystals. A theoretical model of the BDT, which makes it possible to estimate the value of the BDT barrier, is proposed.

It is shown that for cryocrystals with a considerable contribution of the energy of zero-point vibrations to the binding energy a quantum correction must be introduced, using an effective temperature that is proportional to the rms displacements.
Oscillations of the conductivity accompanying two-dimensional magnetic breakdown
Authors: Ginzburg VI. L. , Morgun V. N.
Published: December 2024

The dependence of the static conductivity on the magnetic field under conditions of two-dimensional coherent magnetic breakdown is investigated on the basis of the hypothesis of “quantum traps” [A. A. Slutskin and L. Yu. Gorelik in: Abstracts of Reports at the 17th All-Union Conference on Low-Temperature Physics, Kishinev (1982), pp. 154–155]. This dependence has the form of separate peaks, whose amplitudes and widths are determined by the lifetime in the quantum mechanical state and the parameters characterizing the inaccuracy of the meauring instrument. As the lifetime increases and the inaccuracy of the instrument decreases, the amplitude of the peaks increases, while their width decreases, the number of peaks increases.
Effect of electron localization in bismuth films: The influence of surface scattering
Authors: Butenko A. V. , Komnik Yu. F. , Bukhshtab E. I.
Published: December 2024

The electron localization effect in thin bismuth films (100-200 Å thick) leads to an anomalous positive magnetoresistance due to strong spin-orbit interaction for elastic scattering of electrons (τso≪τɸ, where τso is the spin relaxation time due to spin-orbit interaction for elastic scattering of electrons, τɸ is the inelastic scattering time. It was found that on increasing the film thickness (L > 200 Å) a negative component of magnetoresistance appears that is specially pronounced in parallel fields. The change in the shape of the magnetoresistance curves is related to the increase in τso on increasing the thickness as a result of decreased surface scattering; a parallel magnetic field then has an additional influence on the surface scattering contribution.
Bunch-by-bunch position measurement with sub-micron resolution at nanoseconds separation using wideband cavity beam position monitors
Authors: Yang Liu , He Xiaozhong , Zhang Xiaoding , Zhou Kui , Liu Ping , Liu Yi , Long Quanhong , Wang Hanbin , Tian Qing , Shen Xuming , Xiao Dexin
Published: December 2024

We developed a wideband RF cavity beam position monitor (CBPM) with a 217 MHz bandwidth centered at the 4.875 GHz dipole mode frequency as part of the preliminary research for a high-repetition-rate hard x-ray free electron laser project at the Chinese Academy of Engineering Physics. This paper presents new results demonstrating bunch-by-bunch position measurements on electron bunches spaced by 2.3 ns (4 bunches per train). Over a measurement range of ∼100 μm, this wideband CBPM achieved a spatial resolution of 0.8 μm at a bunch charge of 80 pC. Position and tilt variations between bunches on the order of 10 μm and 10 μrad, respectively, were clearly resolved. This high spatial and temporal resolution provides a valuable tool for experimental studies on long-range wakefield effects in multi-bunch operational light sources.
Vortex structure manipulation and drag reduction of tandem circular cylinders using a pitching splitter plate
Authors: Sikdar Prabir , Dash Sunil Manohar , Lua Kim Boon
Published: December 2024

In this article, two-dimensional numerical simulations are performed to investigate the effectiveness of a hinged splitter plate for manipulating the unsteady laminar wake regime of tandem circular cylinders (TCCs) at a pitch ratio of G/D = 5 and Reynolds number of Re = UD/υ = 100, where G is the distance between the centers of the cylinders having diameter D, U is the free-stream velocity, and υ is the kinematic viscosity of the fluid. These simulations are conducted using the in-house developed flexible forcing immersed boundary-one-step simplified lattice Boltzmann method (FFIB-OSLBM) solver. The splitter plate is hinged to the upstream cylinder's rear base point (HSPU) that pitches at amplitudes θm (10°–20°) and non-dimensional frequencies Stf (0.1–0.4). The plate length Lf/D is varied between 0 and 1. These pitching parameters substantially influence the wake topologies, vortex-interaction modes, pressure distribution, and flow-induced forces on the cylinders. Moreover, the TCC-HSPU combination exhibits four different wake patterns. In Type-I, regular vortex shedding occurs, with the upstream cylinder vortex (UCV) dominating the plate vortex (PV) in the cylinder gap region. The stronger and bigger PV in Type-II forms parallel vortex streets. In Type-III, the PV becomes strong enough to prevent the shedding of UCV. Finally, in Type-IV, the PV attains its maximum strength, and its interaction with UCV forms a new vortex that dominates the cylinder gap region. Among them, Type-II and Type-III regimes are associated with a lower range of drag force on TCC-HSPU configurations. In the considered parametric space, the TCC-HSPU arrangement achieves a maximum drag reduction of 43% compared to the TCC when Lf/D = 1.00, Stf = 0.20, and θm = 15°.
Numerical simulation of rarefied binary mixture pressure-driven flow in channel with counteracting wall drag
Authors: Kosyanchuk Vasily
Published: December 2024

Present paper studies the rarefied flow of binary Neon–Argon mixture in plane channel induced by pressure gradient and counteracting drag by moving walls. The problem is studied numerically using Direct Simulation Monte Carlo method. It is demonstrated that drag force induced by motion of channel walls leads to the effect of enhanced mixture separation. Stronger separation effects are unexpectedly observed for denser gases and thorough explanation for such behavior is provided. It was also shown that gas flow rate in the channel decreases non-monotonically with increasing speed of the walls, having local minimum at wall speeds close to mean thermal speed of molecules. The influence of other parameters, such as channel length and accommodation coefficient on the walls, was also examined.
Assessment of multiple hemorheological properties in microfluidic environment
Authors: Kang Yang Jun
Published: December 2024

Measuring and monitoring hemorheological properties provide valuable insights into diseases. To effectively detect impaired blood, it is necessary to quantify the multiple hemorheological properties. However, most of the previous methods only provide single blood property. They require bulky and expensive syringe pumps for precise on–off control. In this study, to resolve several issues, a novel method for measuring multiple hemorheological properties (fluidic resistance, blood viscosity, time constant, compliance coefficient, red blood cell [RBC] aggregation index, and RBC sedimentation index) is proposed by analyzing blood images in microfluidic channels, where transient blood flow is induced by a portable air-compression pump. A microfluidic device consists of an inlet, a test chamber joined to a main channel, and a reservoir. The outlet of test chamber is connected to an air damper, which contributes to stopping blood flow promptly. A fluid circuit model of the proposed microfluidic channels is constructed for estimating flow rate and pressure in the main channel. First, the proposed method is used to obtain the rheological properties of glycerin solution (30%). The normalized difference between the proposed method and the reference value is less than 4%. Subsequently, the proposed method is adopted to detect differences in the medium (1× phosphate-buffered saline, dextran solution: 20 mg/ml) and hematocrit (30%–60%). All hemorheological properties exhibit substantial differences with respect to the hematocrit and medium. The proposed method yields comparable results when compared to the previous methods. In conclusion, the proposed method can measure multiple hemorheological properties by analyzing blood flow in microfluidic channels.
Transport and energetics of bacterial rectification
Authors: Anand Satyam , Ma Xiaolei , Guo Shuo , Martiniani Stefano , Cheng Xiang
Published: December 2024

Randomly moving active particles can be herded into directed motion by asymmetric geometric structures. Although such a rectification process has been extensively studied due to its fundamental, biological, and technological relevance, a comprehensive understanding of active matter rectification based on single particle dynamics remains elusive. Here, by combining experiments, simulations, and theory, we study the directed transport and energetics of swimming bacteria navigating through funnel-shaped obstacles—a paradigmatic model of rectification of living active matter. We develop a microscopic parameter-free model for bacterial rectification, which quantitatively explains experimental and numerical observations and predicts the optimal geometry for the maximum rectification efficiency. Furthermore, we quantify the degree of time irreversibility and measure the extractable work associated with bacterial rectification. Our study provides quantitative solutions to long-standing questions on bacterial rectification and establishes a generic relationship between time irreversibility, particle fluxes, and extractable work, shedding light on the energetics of nonequilibrium rectification processes in living systems.
Indexing a withdrawal from one’s previously-taken position
Authors: Zhang Shuling , Qiu Mengying
Published: December 2024

Using conversation analysis as the research method, this article investigates what participants do with the
multiple saying duì duì duì (‘right right right’) when they take divergent positions in Mandarin Chinese
conversation. A participant may deploy duì duì duì to claim recalibrating understanding, which indexes a backdown
or withdrawal from a previously-taken position. There are two trajectories to make such concessions. One is “Claim X — Concession
(duì duì duì) — Claim Y”, with Y taking the co-participant’s perspective into account and duì duì
duì serving as a pivot for the new Claim Y. The other is “Claim X — Concession (duì duì duì)”, in
which conceding means abandoning. Through these trajectories, participants find out something different and implicate that their
prior action is problematic due to not taking something into account, so they concede and change. This article will contribute to
both concession and multiple sayings studies.
Effects of indirect corrective feedback and teacher encouragement on EFL students’ writing accuracy
Authors: Fan Ning , Ma Yingying
Published: December 2024

This study examines the effects of indirect corrective feedback and positive affective teacher comments on English
as a foreign language (EFL) students’ writing accuracy in new writings and revisions. Four intact classes of EFL students
(n = 231) were randomly assigned to four groups: (1) Indirect-coded corrective feedback (ICCF), (2) ICCF +
positive teacher comments, (3) Indirect non-coded corrective feedback (INCCF), (4) INCCF + positive teacher comments. Two-way
factorial ANOVAs investigated the effects of indirect CF (ICCF or INCCF) and the presence or absence of positive teacher comments
on students’ writing accuracy in new writings and in revisions. Results revealed that, beginning with similar levels of writing
accuracy and attitudes toward writing feedback, groups provided positive teacher comments significantly outperformed the groups
not provided positive comments in both new writings and revisions. There was no significant difference for the type of corrective
feedback provided, nor was there a significant interaction effect. This study provides evidence that teacher encouragement through
positive affective comments can have a significant impact on students’ writing acquisition. The paper concludes with implications
for EFL writing instruction.
Rebranding Unsustainable Destinations: The Case Study of Miami Beach Breaking Up with Spring Break
Authors: Spezzano Walter , Lusby Carolin
Published: December 2024

Spring break has long been a double-edged sword for destinations, especially in Florida, United States, where cities gain economic benefits while facing significant challenges that impact the safety and sustainability of these areas. This case study examines the strategic response of Miami Beach to the negative impacts of spring break, including overcrowding, rising crime rates, and disruption to community life, which led to states of emergency in 2021, 2022, and 2023. To face these issues, the city government, in collaboration with the local destination marketing organization (DMO), crafted a strategy that included the
Miami Beach Is Breaking Up With Spring Break
marketing campaign. This campaign utilized a breakup metaphor to communicate the city’s firm stance against unruly tourist behavior. Through rebranding, Miami Beach aimed to redefine itself as a calmer, safer, and more community-focused destination, prioritizing the well-being of both residents and visitors. The campaign effectively conveyed this message by combining emotional narratives with persuasive language, contrasting disruptive behavior with the city’s core values. This case highlights the role of storytelling in destination rebranding as a tool to address tourism-related challenges, fostering long-term sustainability and community well-being.

Information

© The Authors 2024
Suppression of hyperuniformity in hydrodynamic scalar active field theories
Authors: Padhan Nadia Bihari , Voigt Axel
Published: December 2024

The coarsening dynamics at late times in phase-separating systems lead to universally hyperuniform patterns. This is well known for scalar field theories, such as the Cahn–Hilliard equation, but has also been shown for dry scalar active field theories. We demonstrate the role of hydrodynamic interactions in influencing hyperuniformity in a wet active system described by active model H. Our direct numerical simulations reveal that, while (passive) model H shows hyperuniformity in the coarsening regime, the interplay of activity and hydrodynamic interactions suppresses hyperuniformity in active model H, especially when the activity generates contractile stress in the fluid.
HF-free low-temperature synthesis of MXene for electrochemical hydrogen production
Authors: Mohili Ranjit D , Mahabari Kajal , Patel Monika , Hemanth NR , Jadhav Arvind H , Lee Kwangyeol , Chaudhari Nitin
Published: December 2024

MXenes [two-dimensional (2D) transition-metal carbides, nitrides and carbonitrides] are gaining significant interest as alternative electrocatalysts for the hydrogen evolution reaction due to their excellent properties such as high electrical conductivity, large surface area and chemical stability. MXenes are traditionally synthesized using hydrofluoric acid (HF), which raises safety and environmental concerns due to its highly corrosive and toxic nature. HF introduces fluoride functional groups on the surface of MXenes, and these have been reported to have a detrimental effect on electrocatalysis. As a result, there is growing interest in developing MXenes through non-fluoride routes. Here, we report room-temperature, HF-free, wet-chemical synthesis of MXene using a mixture of hydrogen peroxide and chromium chloride. The newly prepared CH-MXenes possess hydrophilic functionalities (–Cl, –OH and =O). Key advantages of the CH route over HF-based synthesis include the elimination of an additional delamination step, the prevention of MXene restacking via chloride functionalities and the consistent production of high-quality 2D MXenes with a reproducible flake size (∼650 nm). These CH-MXenes exhibit a high surface area, excellent conductivity and enhanced chemical stability, making them suitable for various energy and other applications.
Simulation of plasma and neutral transport in PISCES-RF using SOLPS-ITER*
Authors: Islam M S , Lore J D , Kumar A , Dhamale G , Baldwin M J , Nishijima D , Tynan G R , Rapp J
Published: December 2024

In this research, the fluid plasma transport code SOLPS-ITER is applied and validated against experimental data from the plasma interaction surface component experimental station (PISCES)-RF linear plasma device to establish a physics basis for plasma and neutral transport in its two magnetic field (B-field) geometry setups-(1)the cusp and (2) non-cusp or linear B-field. The main focus of this study is to understand (1) radial plasma transport (2) heat and particle loads on the upstream dump and downstream target plate, and (3) the physics of plasma-neutral interactions in PISCES-RF. The simulation setup adheres to typical PISCES-RF experimental conditions, with a 2D helicon power deposition profile as an input heating source. SOLPS-ITER simulations reproduce experimental conditions with the Bohm diffusion model for both B-field configurations of the PISCES-RF experiment. Major energy loss channels include neutral radiation and power deposited on the wall and dump plate, with only 1

%

of the input power reaching the target. The ionization front is well confined near the dump plate due to the heating and puffing regions. Additionally, SOLPS-ITER simulation results are also found to be in very good agreement with the particle-in-cell calculations using the code-PICOS++ which supports the validity of SOLPS in low collisionality regime.
The impact of preheating on wide-angle VISAR diagnostic in indirect-drive implosion experiments
Authors: Zhang Qing , Wu Yuji , Yu Wenli , Guan Zanyang , Li Yulong , Ren Kuan , Song Tianming , Liang Juxi , Chen Xudan , Shen Ruiqiang , Wang Feng
Published: December 2024

The symmetry diagnosis of the implosion process can reflect the compression evolution, as well as laser ablation symmetry and hydrodynamic instability, which is a significant research topic for improving implosion performance in inertial confinement fusion (ICF). The wide-angle velocity interferometer system for any reflector (VISAR) has the ability to diagnose three-dimensional implosion compression. However, the preheating phenomenon limits the applicability of wide-angle VISAR. This work developed a radiation hydrodynamics simulation model of wide-angle VISAR preheating to investigate the effect of various parameters on diagnostic system performance. It specifically investigates the impact of ablator layer thickness, shielding thickness, laser energy, and M-band x-ray radiation fractions on the wide-angle VISAR. The results indicate that excessively thin ablator and shielding layers result in the preheating of the ellipsoidal mirror. The increased peak radiation temperature shifts the energy spectrum into the M-band region, causing the ellipsoidal mirror to be preheated and melted, and the wide-angle VISAR to lose its diagnostic capability. Indirect drive implosion experiments were carried out to verify the simulation results. When the peak radiation temperature is 160 eV, with insufficient thickness of the ablator layer and the shielding layer, the shock wave enters the CH layer for 0.50 ns, and the ellipsoidal Al mirror will be completely melted. However, the current wide-angle VISAR can obtain velocity information at lower drive energy. In the future work, it is planned to shield the preheating effects, which will be helpful to promote the application of wide-angle VISAR for 3D symmetry diagnostics under high radiation temperature conditions and ultimately provide an important diagnostic tool for ICF.
Heat flux mitigation characteristics in the radiative divertors with multi-peaks of heat flux in the large helical device
Authors: Hayashi Yuki , Masuzaki Suguru , Kobayashi Masahiro , Kawamura Gakushi , Mukai Kiyofumi , Tanaka Hirohiko , Murase Takanori
Published: December 2024

In this study, the effects of impurity seeding on the one- and two-dimensional heat flux profiles of the large helical device divertor with a multi-peaks of heat flux were investigated, focusing on the heat-flux-reduction characteristics at the two peaks. The divertor heat flux profile was reconstructed using finite element analysis based on the temperature distribution measured via infrared thermography. The divertor heat flux profiles were calculated using the EMC3-EIRENE code considering the impurity seeding. In general, the calculated results were consistent with the experimental observations, including the heat flux value and reduction via impurity seeding. The reduction in the divertor heat flux due to impurity seeding was almost similar at different heat flux peaks and exhibited little dependence on the heating power variance. The difference between the low- and high-heating-power cases is discussed by tracing the magnetic field lines from the divertor plate and considering the penetration depth of the impurity particles into the scrape-off layer plasma.
A novel angle sensitive rotary magnetorheological damper
Authors: Xi Jun , Wang Yingjian , Wang Meng , Ding Xiaoyu , Wang Jinjie , Gao Peixin , Yu Tao
Published: December 2024

Traditional shear type rotary magnetorheological (MR) dampers have a constant working gap in the activation zone, and the damping force output is only controlled by the excitation current. By combining with closed-loop control algorithms and devices, variable damping force output can be achieved. However, this closed-loop control system is complex and requires additional control equipment. If the control system fails, it is impossible to achieve the output of damping force changes, which is unacceptable in some extremely high reliability, low-cost, and narrow space working conditions. In order to achieve variable damping force output of the rotary MR damper throughout the full piston stroke under constant excitation current, a novel variable positional damping rotary MR damper (VPD-RMRD) is proposed in this study. By presetting the size of the activation gap between the piston and cylinder at different angular positions, it is possible to achieve damping force variation output throughout the entire piston stroke without the need for additional control devices. This variable damping output method only requires a constant excitation current. The prototype of VPD-RMRD has been manufactured and subjected to performance testing. In order to verify the feasibility of applying VPD-RMRD to vibration reduction, this study applied it to the seat suspension system. The experimental results show that the maximum reduction in acceleration transmission rate is more than 20%. The proposal of VPD-RMRD provides a new solution for vibration reduction in narrow spaces, high reliability, and low-cost operating conditions.
3D arc-shaped structure design of compression-twist coupling metamaterial
Authors: Chen Xuan , Li Liuyang , Wang Haibing , Huang Shuping , Feng Miaolin
Published: December 2024

Compression-twist coupling (CTC) metamaterials are special mechanical metamaterials that convert axial force into circumferential force. Based on the dislocated re-entrant structure, a novel structure with line-shaped polyline rods is proposed to achieve the CTC effect. To reduce the stress concentration, a corresponding arc-shaped CTC structure is further designed, which is the focus structure of our study. The influence of the geometrical parameters of the arc-shaped structures on the CTC effect is explored through energy-based theoretical analysis, finite element simulation, and validation experiments. Finally, the CTC effects of extended single-side arc-shaped and multi-arc design structures are discussed. Compared with previous designs, the novel structure proposed in this work enhances the design flexibility and achieves a significant CTC effect, which can serve as a reference for the design of new CTC metamaterials.
Explicit and implicit quantum correlation dynamics of qubits interacting with thermal baths
Authors: Zahia Ahmed A , Abd-Rabbou M Y , Megahed Ahmed M
Published: December 2024

This paper investigates the dynamics of quantum correlations, specifically entanglement, steering, and Local Quantum Uncertainty (LQU), in a bipartite qubit system coupled to independent, isolated circular spin-star baths. Contrary to intuition, we demonstrate that substantial quantum correlations can persist even in the absence of direct bath-bath interactions. Our findings reveal that the symmetry of the system and initial atomic populations are critical factors in facilitating robust steering and strong quantum correlations. We further show that increasing the internal bath coupling can enhance the quantum correlations between the baths regardless of indirect interaction. Conversely, increasing the internal bath coupling and bath-qubit coupling can weaken the quantum correlations between the central qubits. Interestingly, indirect coupling between the baths, mediated by the qubits, can lead to robust entanglement and steering. The LQU provides deeper insights into the interplay between uncertainty and correlation. The initial conditions minimize uncertainty and maximize correlations, while imbalances result in increased LQU. These results have profound implications for quantum information processing and control, offering potential strategies for optimizing quantum device performance and protocol design.
Ion acoustic solitons and periodic waves with dynamical features around the supercritical values in relativistic unmagnetized plasmas
Authors: Rahman Md Obaidur , Hafez M G , Barua Sagar , Kauser M A
Published: December 2024

This study examines the nonlinear propagation and dynamic behavior of ion acoustic (IA) waves in unmagnetized relativistic plasmas (UMRP), consisting of relativistic warm ion fluids and Cairns-distributed inertialess electrons and positrons. Using the well-established reductive perturbation method, the quartic Korteweg–de Vries equation (KdVE) is derived with the existence of super-critical value to investigate the dynamical features and propagation characteristics of IA waves in such plasmas. Additionally, a traveling wave transformation is applied to develop a planar dynamical system, and its phase portrait is analyzed to gain insights into the nonlinear wave behavior. The impact of plasma parameters on the propagation and dynamic characteristics of IA waves is also explored. The findings reveal that plasma parameters have a substantial effect on the propagation properties of IA waves and their associated electric fields, particularly when the Lorentz relativistic factor (LRF) is expanded up to 20 terms, as opposed to the conventional two or three terms It is also observed that minor variations in any parameter can profoundly influence the bifurcation features and nonlinear propagation dynamics of IA wave at the super-critical value. These findings could contribute to a better understanding of solitary wave dynamics in astrophysical environments such as magnetospheres, neutron stars, dark matter halos, and white dwarfs, etc.
Fractional Bateman equations in the Atangana-Baleanu sense
Authors: Jornet Marc
Published: December 2024

Considering experimental evidence of fractional behavior for alpha-type radioactive decay, this paper is placed in the context of the fractional Bateman equations with several memory orders. Recent papers studied these equations for Caputo/Riemann-Liouville fractional calculus and suggested the investigation of alternative fractional operators. We focus on the Atangana-Baleanu (AB) formulae, specifically on the associated Volterra integral equations to preserve mass balance. On the one hand, we deal with the associated mathematics of the Bateman model: we solve it in terms of multivariate Mittag-Leffler functions, by means of the Mikusiński operational method, which is more general than the Laplace-transform technique. On the other hand, we address the physical implications of the AB calculus, discussing relevant issues and deficiencies that indicate alternative lines of research.
A particle's perspective on screening mechanisms
Authors: Sevillano Muñoz Sergio
Published: December 2024

Screening mechanisms are a natural method for suppressing long-range forces in scalar-tensor theories as they link the local background density to their strength. Focusing on Brans-Dicke theories, those including a non-minimal coupling between a scalar degree of freedom and the Ricci scalar, we study the origin of these screening mechanisms from a field theory perspective, considering the influence of the Standard Model on the mechanisms. Additionally, we further consider the role of scale symmetries on screening, demonstrating that only certain sectors, those obtaining their mass via the Higgs mechanism, contribute to screening the fifth forces. This may have significant implications for baryons, which obtain most of their mass from the gluon's binding energy. However, a definitive statement requires extending these calculations to bound states. We show that the non-minimally coupled field's interactions with the Higgs lead to an extensive region of the parameter space where screening mechanisms create spatially dependent fermion masses. We say that the field over-screens when this effect is more significant than the fifth forces suppressed by screening mechanisms, as we illustrate for the chameleon and symmetron models.
Understanding responses to multi-electrode epiretinal stimulation using a biophysical model
Authors: Vilkhu Ramandeep S , Vasireddy Praful K , Kish Kathleen E , Gogliettino Alex R , Lotlikar Amrith , Hottowy Pawel , Dabrowski Wladyslaw , Sher Alexander , Litke Alan M , Mitra Subhasish , Chichilnisky E J
Published: December 2024

Objective. Neural interfaces are designed to evoke specific patterns of electrical activity in populations of neurons by stimulating with many electrodes. However, currents passed simultaneously through multiple electrodes often combine nonlinearly to drive neural responses, making evoked responses difficult to predict and control. This response nonlinearity could arise from the interaction of many excitable sites in each cell, any of which can produce a spike. However, this multi-site activation hypothesis is difficult to verify experimentally. Approach. We developed a biophysical model to study retinal ganglion cell responses to multi-electrode stimulation and validated it using data collected from ex vivo preparations of the macaque retina using a microelectrode array (512 electrodes; 30 µm pitch; 10 µm diameter). Results. First, the model was validated by using it to reproduce essential empirical findings from single-electrode recording and stimulation, including recorded spike voltage waveforms at multiple locations and sigmoidal responses to injected current. Then, stimulation with two electrodes was modeled to test how the positioning of the electrodes relative to the cell affected the degree of response nonlinearity. Currents passed through pairs of electrodes positioned near the cell body or far from the axon (>40 µm) exhibited approximately linear summation in evoking spikes. Currents passed through pairs of electrodes close to the axon summed linearly when their locations along the axon were similar, and nonlinearly otherwise. Over a range of electrode placements, several distinct, localized spike initiation sites were observed, and the number of these sites covaried with the degree of response nonlinearity. Similar trends were observed for three-electrode stimuli. All of these trends in the simulation were consistent with experimental observations. Significance. These findings support the multi-site activation hypothesis for nonlinear activation of neurons, providing a biophysical interpretation of previous experimental results and potentially enabling more efficient use of multi-electrode stimuli in future neural implants.
Formulation and optimization study of nanodelivery system encapsulating guava wild leaf extract for potential anti-inflammatory properties
Authors: Nguyen Phuoc-Vinh , Nguyen Quang-Vinh , Nguyen Minh-Trung , Nguyen Bac V G , Thi Le Thanh-Thuy , Mac Huy-Hieu
Published: December 2024

Psidium guajava L. (Myrtaceae) has long been used in folk medicine as a potent therapeutic agent for the treatment of inflammation. Despite its potential, the application of this natural source remains limited because of its instability and poor permeability through biological barriers. Among different available strategies, niosomes, a surfactant-based nanovesicular system, may help maximize the application of this plant extract. Indeed, this nanosystem represents several advantages in drug delivery such as improved bioavailability, reduced toxicity, better drug stability, possible targeting and controlled release, biocompatability, and biodegradability. The aim of this study was to develop and optimize a formulation of a niosomal system for encapsulating guava leaf extract (GLs-N) for anti-inflammatory applications. The niosomes were fabricated using the ethanol injection method and optimized in terms of the surfactant, cholesterol, and GLs content using an experimental design model. The finalized niosomes were physicochemically characterized and tested for their encapsulation efficiency (EE), stability, permeability, and in vitro and in vivo anti-inflammatory activities in a zebrafish model. As a result, the optimized niosomes were of 167.9 ± 1.845 nm in size, with a PDI of 0.212 ± 0.005, negatively charged, and with an EE of 65.54%. Compared to free GLs, GLs-niosomes presented a significant increase in permeability and possessed good stability over 28 d at both 4 °C and 25 °C. Most importantly, in vitro and in vivo anti-inflammatory studies confirmed that the anti-inflammatory activity of GLs-niosomes was much stronger than that of free GLs, and 4.2 fold stronger than that of ibuprofen. Collectively, this study was successful in developing and optimizing a potent niosomal structure for an effective delivery of wild GL in the treatment of inflammation.
Preparation of biodegradable, antibacterial core-spun yarns with braided structures using QAS/PLA micro/nanocomposites
Authors: Xu Jun , Zhao Xingyu , Lei Zhenzhen , Jia Huimin , He Haolong , Gong Genghao , Wang Jing , Wang Tiegang
Published: December 2024

Medical antibacterial textiles play a vital role in tackling the issue of bacterial infection. Traditional surgical sutures face significant challenges due to wound infection caused by bacteria and breakage and scars caused by poor suture strength. Therefore, a new antibacterial and high-strength suture preparation strategy with wide clinical applicability was highly desired. In this study, a biodegradable quaternary ammonium salt (QAS)/polylactic acid (PLA) core-spun yarn with excellent antibacterial and mechanical properties was prepared by conjugated electrospinning technology combined with the braiding process. The antibacterial test results revealed the best overall performance of the PLA micro/nanofiber core-spun yarn with 0.3 wt% QAS antibacterial agent. The antibacterial rate against Escherichia coli and Staphylococcus aureus was 94.49% and 94.00%, respectively, which could effectively solve the problem of wound infection caused by bacteria. In addition, we used the diamond-braided structure to address the poor strength and fragility of the traditional suture strength. The braiding angle of 30° and 45° could effectively enhance the mechanical properties of the yarn, and the breaking strength was also in line with the industry standard. The study proposed that the degradable QAS/PLA micro/nanofiber core-spun yarn, due to its excellent antibacterial and mechanical properties, could find application in medical protection. This provided a new avenue for research into new antibacterial surgical sutures.
Injectable nanocomposite hydrogels with co-delivery of oxygen and anticancer drugs for higher cell viability of healthy cells than cancer cells under normoxic and hypoxic conditions
Authors: Kehr Nermin Seda
Published: December 2024

Injectable nanocomposite hydrogels (NC hydrogels) have the potential to be used for minimally invasive local drug delivery. In particular, pH-sensitive injectable NC hydrogels can be used in cancer treatment to deliver high doses of anticancer drugs to the target site in cancer tissue without damaging healthy tissue. Recent studies have shown that in addition to stimuli-responsive delivery of anticancer drugs to cancer cells, oxygen delivery to the hypoxic environment of cancer tissue can lead to advanced effects, as hypoxia and an acidic pH are common characteristics of cancer tissue. However, few studies have investigated the effects of simultaneous administration of oxygen (O2) and pH-dependent anticancer drugs via injectable NC hydrogels on the viability of healthy and cancer cells under normoxic and hypoxic conditions. In this context, we describe the synthesis of injectable NC hydrogels composed of pH-responsive nanomaterials carrying oxygen and anticancer drugs. Our system provides sustained O2 release and pH-responsive sustained release of anticancer drugs for 15 and 30 d, respectively. Moreover, O2 delivery and/or simultaneous delivery of O2 and anticancer drug resulted in higher cell survival of healthy fibroblast cells than malignant Colo-818 cells under hypoxic conditions (1% O2) after 7 d of incubation.
High-purity amorphous silica from industrial filter cake waste: synthesis and process optimization
Authors: Negash Ermias Abebe , Brehane Tesfamariam Belay , Mengesha Getinet Asrat , Shasho Yonas , Mekuriya Yeabsira Sisay , Beyene Sena Tadesse
Published: December 2024

The globally increasing concern over industrial byproducts highlights the need for sustainable waste management solutions. Repurposing such byproducts offers a promising approach to sustaining development. This study focuses on the extraction of silica from filter cake waste (FCW). Amorphous silica was successfully synthesized through sol–gel method using acetic acid as the precipitation agent. XRD and SEM analyses were used to confirm the crystal structure of silica to be amorphous, while FTIR studies identified characteristic Si−O−Si bonds, indicating high purity of the extract. The silica purity was further validated by EDS analysis to be about 98.98%. Optimization of the extraction process was carried through variation of parameters such as NaOH concentration, temperature, and stirring time, resulting in a maximum yield of 54%.
A variational network for biomedical images denoising using bayesian model and auto-encoder
Authors: Tchagna Kouanou Aurelle , Karambal Issa , Gaba Yae , Tchapga Tchito Christian , Dikande Simo Alain Marcel , Alla Takam Clemence , Tchiotsop Daniel
Published: December 2024

Background and Objective. Auto-encoders have demonstrated outstanding performance in computer vision tasks such as biomedical imaging, including classification, segmentation, and denoising. Many of the current techniques for image denoising in biomedical applications involve training an autoencoder or convolutional neural network (CNN) using pairs of clean and noisy images. However, these approaches are not realistic because the autoencoder or CNN is trained on known noise and does not generalize well to new noisy distributions. This paper proposes a novel approach for biomedical image denoising using a variational network based on a Bayesian model and deep learning. Method. In this study, we aim to denoise biomedical images using a Bayesian approach. In our dataset, each image exhibited a same noise distribution. To achieve this, we first estimate the noise distribution based on Bayesian probability by calculating the posterior distributions, and then proceed with denoising. A loss function that combines the Bayesian prior and autoencoder objectives is used to train the variational network. The proposed method was tested on CT-Scan biomedical image datasets and compared with state-of-the-art denoising techniques. Results. The experimental results demonstrate that our method outperforms the existing methods in terms of denoising accuracy, visual quality, and computational efficiency. For instance, we obtained a PSNR of 39.18 dB and an SSIM of 0.9941 with noise intensity α = 10. Our approach can potentially improve the accuracy and reliability of biomedical image analysis, which can have significant implications for clinical diagnosis and treatment planning. Conclusion. The proposed method combines the advantages of both Bayesian modeling and variational network to effectively denoise biomedical images.
High gain boost DC-DC converters with minimized switch stress for renewable energy applications
Authors: Swadi Mahmood , Hamza Ali Yaqoub , Salem Mohamed , Mohamed Faisal A
Published: December 2024

This paper introduces a new series of non-isolated boost DC-DC converters, showcasing a novel high step-up switching cell integrated into a basic boost converter to form a new transformerless converter design. The primary focus is on achieving significant voltage gains with moderate duty cycles while minimizing the stress on semiconductor devices. Comprehensive comparative analyses underline the new converter’s advantages over existing models regarding voltage and current stresses, component count, and performance metrics. Additionally, the converter’s design simplifies transistor driving by utilizing a single switch, enhancing operational ease. Detailed theoretical explanations are provided for continuous conduction mode (CCM), discontinuous mode (DCM), and boundary condition mode (BCM), including equations for voltages and currents. The proposed converter’s effectiveness is examined through simulation and experimental validation. A 260-watt PV panel supplied by the proposed converter prototype demonstrates the converter’s impressive boosting capability and high efficiency across 0.5 a duty cycle with a constant input voltage, providing solid proof of concept for the proposed designs. These findings promise substantial advancements in designing and applying high-gain boost converters in various electronic, industrial, and renewable energy applications.
MRE11-independent effects of Mirin on mitochondrial DNA integrity and cellular immune responses
Authors: Aasumets Koit , Hangas Anu , Fragkoulis Georgios , Bader Cyrielle P. J. , Erdinc Direnis , Wanrooij Sjoerd , Wanrooij Paulina H. , Goffart Steffi , Pohjoismäki Jaakko L.O.
Published: December 2024

Mirin, a chemical inhibitor of MRE11, has been recently reported to suppress immune response triggered by mitochondrial DNA (mtDNA) breakage and release during replication stalling. We show that while Mirin reduces mitochondrial replication fork breakage in mitochondrial 3´-exonuclease MGME1 deficient cells, this effect occurs independently of MRE11. We also discovered that Mirin directly inhibits cellular immune responses, as shown by its suppression of STAT1 phosphorylation in Poly (I:C)-treated cells. Furthermore, Mirin also altered mtDNA supercoiling and accumulation of hemicatenated replication termination intermediates—hallmarks of topoisomerase dysfunction—while mitigating topological changes induced by the overexpression of mitochondrial TOP3A, including TOP3A-dependent strand breakage at the noncoding region of mtDNA. Although Mirin does not seem to inhibit TOP3A activity in vitro, our findings demonstrate its MRE11-independent effects in cells and give insight into the mechanisms of the maintenance of mtDNA integrity.
Blood banking services in critical access hospitals in Kansas: A laboratory perspective
Authors: Nuñez-Argote Letycia , Corns Alexandra , Moser Robert
Published: December 2024

Objectives

To investigate the resource capacity for blood banking in critical access hospitals (CAHs) in Kansas and the experiences of medical laboratory personnel working in them.

Methods

An electronic survey was implemented to record data from all 82 CAHs in Kansas between May and July 2023. The distance between hospitals with no blood bank services and commercial blood banks was calculated.

Results

Only 63.4% of Kansas CAHs located in nonmetropolitan counties reported access to 24/7 blood bank services. In 12.2% of laboratories with 5 or fewer workers, there were no staff proficient in blood bank testing. While 72% of laboratories could perform type and screen and crossmatching, many lacked antibody identification capacity. Only 2 hospitals had the capacity to transfuse packed red blood cells, plasma, and platelets simultaneously if needed, with 20.6% of nonmetropolitan hospitals holding no blood products in inventory.

Conclusions

The blood banking capacity of CAHs in Kansas is influenced by the lack of workforce availability and training, reduced availability of blood products, and distance from facilities where blood is processed. Solutions tailored to the unique rural environment are needed to ensure adequate access to blood for patients.
QOMIC: quantum optimization for motif identification
Authors: Ngo Hoang M , Khatib Tamim , Thai My T , Kahveci Tamer
Published: December 2024

Motivation

Network motif identification (MI) problem aims to find topological patterns in biological networks. Identifying disjoint motifs is a computationally challenging problem using classical computers. Quantum computers enable solving high complexity problems which do not scale using classical computers. In this article, we develop the first quantum solution, called QOMIC (Quantum Optimization for Motif IdentifiCation), to the MI problem. QOMIC transforms the MI problem using a integer model, which serves as the foundation to develop our quantum solution. We develop and implement the quantum circuit to find motif locations in the given network using this model.

Results

Our experiments demonstrate that QOMIC outperforms the existing solutions developed for the classical computer, in term of motif counts. We also observe that QOMIC can efficiently find motifs in human regulatory networks associated with five neurodegenerative diseases: Alzheimer’s, Parkinson’s, Huntington’s, Amyotrophic Lateral Sclerosis, and Motor Neurone Disease.

Availability and implementation

Our implementation can be found in https://github.com/ngominhhoang/Quantum-Motif-Identification.git.
Barber Ant Alopecia
Authors: Carroll Emma , Hughes Rosalind
Published: December 2024

A 26-year-old woman presented with overnight alopecia after encountering ants in her hair, later identified as Pheidole pallidula, "barber ants". Ant-induced alopecia is a rare condition, resulting from mechanical biting and chemical actions by the ants. Spontaneous regrowth usually occurs.