bluuebunny/crossref_metadata_2025 huggingface dataset:
Heparin and Direct Oral Anticoagulants have Different Effects on the Phases of Activation and Spatial Spread of Blood Coagulation
Authors: Ataullakhanov Fazoil I. , Dashkevich Natalya M. , Ovsepyan Ruzanna A. , Vuimo Tatiana A. , Balandina Anna N. , Kuprash Anna D. , Ayusheev Dorzo-Cyren B. , Bernakevich Alexey I. , Sinauridze Elena I.
Published: February 2025

Background Various reactions are involved in the phases of activation and further propagation of coagulation in space. The effects of different anticoagulants on these phases are unknown. Our aim was to study how different anticoagulants affect the activation and propagation phases of coagulation.

Materials and Methods Coagulation in the presence of low-molecular-weight heparin (nadroparin), and direct oral thrombin or factor Xa inhibitors (dabigatran and rivaroxaban, respectively) was studied in vitro and ex vivo via a global blood coagulation assay (Thrombodynamics-4D), which allows simultaneous analysis of thrombin activity in space and the clot growth rate. The ex vivo measurements were carried out in dynamics (8–9 days). The presence of asymptomatic thrombosis after 7 to 8 days of treatment was determined for each group of patients via ultrasound of the lower extremities.

Results All the tested anticoagulants inhibited thrombin generation but resulted in different patterns of thrombin spatial distribution and clot growth. The reversible inhibitors—dabigatran and rivaroxaban—inhibited the initiation phase of coagulation, while further clot growth was altered moderately. Irreversible nadroparin weakly affected the initiation phase of thrombin generation, but unlike dabigatran and rivaroxaban, it could completely suppress spatial thrombin propagation. Asymptomatic thrombosis was observed in 0%, 11%, and 29% of the patients in the nadroparin, dabigatran, and rivaroxaban groups, respectively.

Conclusion Antithrombin-dependent and independent inhibitors act differently on different phases of coagulation. High concentrations of dabigatran or rivaroxaban are insufficient to completely prevent fibrin clot growth, but even small amounts of heparin completely suppress this growth, due to factor IXa inhibition.
Leitlinie zur Impfung von Pferden – 5.
Auflage
Authors:   Arbeitskreis Pferde der Ständigen Impfkommission
        Veterinärmedizin (StIKo Vet)
Published: February 2025

Die Impfung ist eine der wichtigsten Maßnahmen zur Verhinderung von
Infektionskrankheiten und deren Verbreitung. Die Impfungen gegen Tetanus und
West-Nil-Virus sind essentiell um das einzelne Pferd vor der Erkrankung zu
schützen. Diese Infektionen sind nicht kontagiös und werden nicht von Tier zu
Tier weitergegeben. Equine Influenza- (EIV) und Herpesvirusinfektionen (EHV)
sind dagegen hochansteckende, übertragbare Erkrankungen. Neben dem Schutz des
geimpften Einzeltiers soll durch die Impfung möglichst vieler Pferde gegen EIV
und EHV eine breite Herdenimmunität erzielt werden, die Infektionsketten
unterbricht, und so das Einzeltier zusätzlich vor der Erkrankung schützt. Die
Impfung gegen Tetanus sowie Equine Influenza- und Herpesviren gelten als
Core-Impfung beim Pferd. Die Impfung gegen das West-Nil-Virus wird in den
bisherigen Verbreitungsgebieten in Mitteldeutschland und seit 2024 in der
gesamten norddeutschen Tiefebene empfohlen. Je nach weiterer Ausbreitung des
Virus ist perspektivisch die Impfung im gesamten Bundesgebiet anzustreben. Neben
den genannten sind für das Pferd Impfstoffe gegen Dermatomykose, Druse,
Rotavirusinfektionen, Equine Virus Arteriitis und Tollwut zugelassen. Der
Einsatz dieser Impfstoffe kann im Einzelfall sehr sinnvoll sein.
The TRAIN Health Awareness Clinical Trial: Baseline Findings and Cardiovascular Risk Management in Aortic Dissection Patients
Authors: Bacour Nora , Grewal Simran , Tirpan Aytug U. , Theijse Rutger , Erp Olivia Van , Klautz Robert J.M. , Sakalihasan Natzi , Hultgren Rebecka , Grewal Nimrat
Published: February 2025

Background/Objective Acute Type A aortic dissection (ATAAD) is a life-threatening condition requiring timely surgical intervention. Despite successful surgery, postoperative outcomes are frequently suboptimal due to the high frequency of cardiovascular risk factors. This study examines baseline cardiovascular risk factors in a population of ATAAD patients in the Netherlands. Additionally, this study outlines the protocol for a randomized controlled trial, designed to improve postoperative management.

Methods Baseline data were collected from patients with ATAAD. Data were gained through the Stichting Aorta Dissectie Nederland, a Dutch association for aortic dissection patients. The data included information on cardiovascular risk factors and health-related quality of life. A survey was further conducted, to gain more insights into the ATAAD postoperative care experiences of cardiac and vascular surgeons.

Results Among the 50 ATAAD patients in our study, we found significant cardiovascular risk factors, including smoking (36.7%), obesity (34.2%), and hypertension (51.3%). In the surgeon survey (N = 48), 84% of respondents highlighted the significance of lifestyle changes for patients, underscoring the need for individualized risk management. These findings underscore the need for tailored postoperative management programs aimed at improving patient outcomes.

Conclusion The results of our study highlight that ATAAD patients require comprehensive postoperative care management strategies. The ultimate goal is to enhance long-term patient outcomes and improve health-related quality of life. To address this need, the TRAIN (Targeted caRdiovAscular rIsk reductioN) Health Awareness platform seeks to implement personalized eHealth-based lifestyle interventions.
Synthesis, Characterization and In Vitro & In Silico Biological Evaluation of New Mannich-Based Rhodanine and Thiazolidine-2,4-Dione Derivatives as Potential Anti-Lung Cancer Agents
Authors: Ateşoğlu Şeyma , Çakır Furkan , Şenol Ayşe Merve , Tokalı Pelin , Şenol Halil , Tokalı Feyzi Sinan , Akbaş Fahri , Kalay Erbay
Published: February 2025

In this study, ten new rhodanine and thiazolidine-2,4-dione derivatives based on Mannich-modified vanillin were synthesized, characterized, and evaluated for their anticancer potential against A549 lung cancer and BEAS-2B normal cells. Among them, compound 5c exhibited the most potent anticancer activity, with an IC50 of 2.43 µM and a selectivity index of 10.91, showing higher selectivity than the reference drug sorafenib. Molecular docking studies suggested 5c as a strong potential EGFR inhibitor, supported by a docking score of -9.827 kcal/mol and key interactions with residues such as Met-793, Leu-788, and Phe-856. Molecular dynamics simulations further confirmed the stability of the 5c-EGFR complex. ADMET predictions indicated favorable pharmacokinetic and safety profiles for 5c, including high permeability, oral absorption, and no significant toxicity. These findings highlight 5c as a promising lead compound for targeted lung cancer therapy, warranting further preclinical studies.
In-hospital Mortality in Patients with Lower Gastrointestinal Bleeding: Development and Validation of a Prediction Score
Authors: Dajti Elton , Frazzoni Leonardo , Castellet-Farrús Sílvia , Guardiola Jordi , Sinagra Emanuele , Anderloni Andrea , Ferrara Francesco , Gkolfakis Paraskevas , Camus Duboc Marine , Mandarino Francesco Vito , Sadeghi Anahita , Lorenzo-Zúñiga Vicente , Perez Sandra , Triantafyllou Konstantinos , Curado Maria Paula , Facciorusso Antonio , Collatuzzo Giulia , Hassan Cesare , Radaelli Franco , Fuccio Lorenzo
Published: February 2025

Background and study aims:
Lower gastrointestinal bleeding (LGIB) is a common condition linked to increased morbidity, healthcare costs, and mortality. Currently, no prospectively validated prognostic model exists to predict mortality in LGIB patients. Our aim was to develop and validate a risk score that could accurately predict in-hospital mortality of patients admitted for LGIB.
Patients and methods:
Patient data from a nationwide cohort study in 15 centers in Italy (2019-2020) were used to derivate the risk score (Acute Lower gastrointestinal Bleeding and In-hospital mortality, ALIBI score); the model was then externally validated in a cohort of consecutive patients hospitalized for LGIB in 12 centers from six countries (Italy, Spain, France, Greece, Iran, Brazil) in 2020-2024. The main outcome was in-hospital mortality; we also reported rebleeding rates and in-hospital mortality rate stratified by risk score and timing of colonoscopy.
Results:
Among 1,198 patients in the derivation cohort, 105 (8.8%) rebled, 41 (3.4%) died. Age, Charlson Comorbidity Index (CCI), in-hospital onset, hemodynamic instability, and creatinine levels were independent predictors of in-hospital mortality. The model demonstrated excellent discrimination (AUROC=0.813, 95%-CI: 0.752-0.874) and calibration. In the validation cohort (n=752 patients), the model's good discrimination (AUROC=0.792, 95%-CI: 0.720-0.863) and calibration were confirmed. Patients were categorized as low (0-4 points, 1% mortality), intermediate (5-9 points, 4.6% mortality), or high risk (10-13 points, 19.1% mortality).
Conclusions:
A new validated score effectively predicts in-hospital mortality in LGIB patients, aiding in risk stratification and management.
Subcutaneous Fat Necrosis of the Newborn
Authors: Shafi Saba , Kahwash Samir B.
Published: February 2025

This is an image-based clinical vignette showing pathologic findings typical of subcutaneous fat necrosis of the newborn (SFNN). The infant—a 15-month-old girl—presented with indurated subcutaneous masses of unknown etiology. This case is a reminder that SFNN, while more common in the newborn period, can occur throughout infancy. It also reminds us that the rare metabolic disorder (Lesch–Nyhan syndrome) may be associated with lesions that can appear somewhat similar under the microscope.
Where the rubber meets the road
Authors: Patrick Chris
Published: February 2025

Experimental and theoretical work improves understanding of the wear of rubber tires.
Global pathwise weak solution for two-dimensional stochastic
Keller-Segel(-Navier)-Stokes system with logistic source
Authors: Xu Fan , Liu Bin
Published: February 2025

This paper addresses the global solvability of a stochastic Keller-Segel(-Navier)-Stokes [SKS(N)S, for short] system with logistic source in a smooth, bounded domain O⊂R2. The main results consist of two parts. First, we prove the existence of a unique global pathwise weak solution for the SKSS system, where the chemical concentration equation is affected by small conservative noise, and the Stokes (slow fluid) equations are perturbed by multiplicative Gaussian noise. Second, we show that the SKSNS system also admits a unique global pathwise weak solution when only the Navier-Stokes equations are influenced by multiplicative Gaussian noise. To establish these results, we use the Galerkin approximation scheme combined with the stochastic compactness method.
Biomembrane structure at the molecular level and its application in precision medicine
Authors: Wang Zicheng , Tian Zhiyuan , Gao Jing , Wang Hongda
Published: February 2025

Biomembranes are fundamental to our understanding of the cell, the basic building block of all life. They form important barriers between the cytoplasm and the microenvironment of the cell and separate organelles within cells. Despite substantial advances in the study of cell membrane structure models, they are still in the stage of model hypothesis due to the high complexity of the components, structures, and functions of membranes. In this review, we summarized the progresses on membrane structure, properties, and functions at the molecular level using newly developed technologies and discussed some challenges and future directions in biomembrane research from our perspective. Moreover, we demonstrated the dynamic functions of membrane proteins and their role in achieving early detection, precise diagnosis, and the development of personalized treatment strategies at the molecular level. Overall, this review aims to engage researchers in related fields and multidisciplinary readers to understand and explore biomembranes for the accurate and effective development of membrane-targeting therapeutic agents.
Giant second harmonic generation in two-dimensional tellurene with synthesis and thickness engineering
Authors: Liu Boqing , Liang Kun , Zhou Qingyi , Khan Ahmed Raza , Lu Zhuoyuan , Yildirim Tanju , Sun Xueqian , Rahman Sharidya , Liu Yun , Yu Zongfu , Lu Yuerui
Published: February 2025

Second harmonic generation (SHG) is a prominent branch of non-linear optics (NLO) heavily reliant on conventional bulk NLO crystals. However, the difficulty in downsizing these crystals imposes technical limitations on the future of miniaturized NLO devices. Tellurene emerges as a promising candidate to overcome these restrictions, excelling in electrical applications and believed to possess a giant second-order optical susceptibility comparable to conventional NLO crystals. In this study, a face-to-face substrate configuration is employed for the synthesis of ultrathin tellurene via PVD. Our findings reveal that tellurene's SHG performance surpasses that of monolayer transition metal dichalcogenides by two orders of magnitude, with maximum efficiency when the flake thickness is between 16 and 20 nm under various wavelengths. High sensitivity to thickness variation encourages post-growth thinning through hydrogen plasma etching, enabling precise engineering of the flake thickness for optimal SHG. This establishes a foundation for controlled tellurene thickness, further broadening its potential in diverse applications.
Rate-induced biosphere collapse in the Daisyworld model
Authors: Arnscheidt Constantin W. , Alkhayuon Hassan
Published: February 2025

There is much interest in the phenomenon of rate-induced tipping, where a system changes abruptly when forcings change faster than some critical rate. Here, we demonstrate and analyze rate-induced tipping in the classic “Daisyworld” model. The Daisyworld model considers a hypothetical planet inhabited only by two species of daisies with different reflectivities and is notable because the daisies lead to an emergent “regulation” of the planet’s temperature. The model serves as a useful thought experiment regarding the co-evolution of life and the global environment and has been widely used in the teaching of Earth system science. We show that sufficiently fast changes in insolation (i.e., incoming sunlight) can cause life on Daisyworld to go extinct, even if life could in principle survive at any fixed insolation value among those encountered. Mathematically, this occurs due to the fact that the solution of the forced (nonautonomous) system crosses the stable manifold of a saddle point for the frozen (autonomous) system. The new discovery of rate-induced tipping in such a classic, simple, and well-studied model provides further supporting evidence that rate-induced tipping—and indeed, rate-induced collapse—may be common in a wide range of systems.
Aerodynamic characteristics of a wing-in-ground effect with micro-vortex generators
Authors: Khare Abhishek , Khurana Shashank
Published: February 2025

Micro-vortex generators (MVGs) are simple passive flow control devices mounted on the base surfaces to mitigate the boundary layer flow separation. The effect of the MVGs installed on the aircraft lifting surfaces, i.e., wing, operating close to the ground (ground effect), is not well understood. In this work, the aerodynamic performance of a National Advisory Committee for Aeronautics (NACA) 4412 wing in ground effect equipped with MVGs is numerically investigated. Installed at 10% or 25% chord of the wing, the MVGs are arranged in a row in a counter-rotating pattern. The analysis is carried out at 18°angle of attack, which is close to the stall angle of attack of the wing. Four different cases of h/b = 0.1, 0.5, 1, and free flight (no ground effect) are considered in this analysis. The Reynolds number based on the wing chord is around 3 million. In this work, the detached eddy simulation (DES) method is employed to accurately capture the high energy levels of the vortex formed behind the MVGs, the wing tip vortex, and their contact with the ground. The DES simulations accurately depict the intricate flow dynamics of the NACA 4412 wing, and the use of MVGs enhances its performance while in close proximity to the ground. A negative Cp peak at the leading edge of the wing increases as it approaches the ground, according to the analysis. For h/b = 0.1, the lower wing over pressure is much higher than for other cases. The Q-criterion shows flow unsteadiness and wing tip vortex evolution. The flow region's vortical structures increase as the wing descends. The flow has the most coherent vortical forms at 0.1 aspect ratio. The ground effect leads to an increase in lift and a decrease in drag as the wing gets closer to the ground.
Vortex shedding from a yaw-oscillating circular cylinder in subcritical flow
Authors: Nasr Esfahani V. , Hanson R. , Ekmekci A.
Published: February 2025

This study investigates vortex shedding characteristics from a circular cylinder subjected to yaw oscillations. The study considers two length-to-diameter ratios (13 and 20) and two Reynolds numbers (5×103 and 1.5×104). Yaw oscillations ranging from θ=0° to 30° are considered at various reduced frequencies from 0.25 to 4. Vortex shedding behavior at the mid-span of the cylinder is measured using hot-wire anemometry. Planar particle image velocimetry (PIV) measurements at the mid-span are used to visualize the near wake. It is shown that an increase in the reduced frequency leads to a shift in the frequency range of vortex shedding toward lower values. Vortices are shed nearer to the base of the cylinder, and vortex shedding becomes more disorganized with increasing reduced frequency. Based on phase-averaged analysis of vortex shedding, the validity of the independence principle (IP) diminishes during the first half cycle beyond θ=15° at low reduced frequencies and beyond θ=20° at moderate reduced frequencies. In the return cycle, the deviation from the IP increases with increasing reduced frequency. The IP prediction is re-established at low yaw angles during the return cycle and for low reduced frequencies. Increasing the length-to-diameter ratio enhanced the organized vortex shedding and elevated the shedding frequency for both static and yaw-oscillating cylinders.
MoO2-modified carbon nanotablets prepared by assembly of a polyoxomolybdate precursor for enhanced microwave absorption properties
Authors: Jiao Huimin , Zhang Jie , Xing Tian , Zhao Ruihua , Du Jianping
Published: February 2025

The electromagnetic wave pollution, originating from various electronic devices, has attracted widespread attention and has brought serious threats to human life. For this situation, the high-efficiency electromagnetic wave absorption (EMA) materials are required. Herein, carbon material modified with molybdenum dioxide is designed and synthesized by carbonizing the Mo-precursor. The Mo oxide/carbide-modified carbon materials are obtained by changing the raw material ratio and carbonized temperatures. The optimal material (MO-2-750) is composed of MoO2 and carbon with uniform nanotablet-like shapes and has excellent impedance matching. The maximum reflection loss of MO-2-750 is about −59.9 dB at a thickness of 2.2 mm, which is nearly 6 times that of carbon material. The effective absorption bandwidth is in the range of 11.29–17.32 GHz. This MoO2-modified carbon material could serve as an EMA platform in the electromagnetic wave absorption fields.
Exact reduction of synchronized systems in higher-dimensional spaces
Authors: Lohe M. A.
Published: February 2025

Exact reduction by partial integration has been extensively investigated for the Kuramoto model by means of the Watanabe–Strogatz transform. This is the simplest of higher-dimensional reductions that apply to a hierarchy of models in spaces of any dimension, including Riccati systems. Linear fractional transformations enable the system equations to be expressed in an equivalent matrix form, where the variables can be regarded as time-evolution operators. This allows us to perform an exact integration at each node, which reduces the system to a single matrix equation, where the associated time-evolution operator acts over all nodes. This operator has group-theoretical properties, as an element of SU(1,1)∼SO(2,1) for the Kuramoto model, and SO(d,1) for higher-dimensional models on the unit sphere Sd−1. Parameterization of the group elements using subgroup properties leads to a further reduction in the number of equations to be solved and also provides explicit formulas for mappings on the unit sphere, which generalize the Möbius map on S1. Exact dimensional reduction also applies to another class of much less-studied models on the unit sphere, with cubic nonlinearities, for which the governing equations can again be transformed into an equivalent matrix form by means of the unit map. Exact integration at each node proceeds as before, where now the time-evolution operator lies in SL(d,R). The matrix formulation leads to exact solutions in terms of the matrix exponential for trajectories that asymptotically approach fixed points. As examples, we investigate partially integrable models with combined pairwise and higher-order interactions.
Nonlinear flow response of flexible fibers driven by Stokes flow
Authors: Pang Bo , Sun Bo Hua
Published: February 2025

The fuzzy, flexible fibers attached to biological surfaces not only reduce drag but also undergo nonlinear deformation under shear flow, and the deformation of these fibers in turn affects fluid flow. This phenomenon is increasingly attracting attention. Due to the complexity of fluid–structure interaction problems, existing analytical solutions such as perturbation methods, integral solutions, and series expansions are still unable to fully address this issue. To tackle this problem, this paper uses COMSOL finite element software for numerical calculations, effectively simulating the interaction between fibers and fluid flow. The results show that this method matches experimental data within a certain velocity range, extending the scope of previous studies and confirming the −1/2 scaling law at higher velocities. Furthermore, the study explores the bending deformation of elastic fibers and the flow field under different fluid loads. This paper provides a new approach for using finite element simulations to model the nonlinear deformation of such fibers, along with visual analysis, which is applicable to similar fluid–structure interaction problems and can provide valuable insights for future scientific research and engineering applications.
A novel parallelized model for simulating massive underwater three-dimensional acoustic fields at medium-high frequencies
Authors: Xiao Wenbin , Liao Siyuan , Wang Yongxian , Deng Zihao
Published: February 2025

Underwater three-dimensional acoustic fields can provide more accurate results than two-dimensional one. However, three-dimensional simulations are computationally intensive and conventional models cannot meet the application demands. A parallelized model for massive underwater three-dimensional acoustic field simulation is proposed in this paper. First, by optimizing variable storage structure and introducing field loops, a serial model is developed based on three-dimensional ray theory, which is capable of simulating massive acoustic fields. Second, a hybrid parallel computing strategy for the serial model is designed at field loops and α loops based on a combination of open multiprocessing and message passing interface, which has both the communication advantage of open multiprocessing and the scalability advantage of message passing interface. Furthermore, a dynamic scheduling algorithm between processes is proposed, which significantly optimizes load balancing by allowing the control process to continuously monitor the computing processes and dynamically distribute tasks. Finally, two sets of numerical simulation experiments, each containing 243 three-dimensional acoustic field computation tasks, are conducted in the Pacific and Atlantic Oceans based on the global ocean reanalysis dataset from 2021. Two experiments demonstrate that the novel parallelized model achieves speed up of 271.76 and 278.65 with 384 cores, which are 6.20 and 5.85 times faster than conventional model, respectively.
Optimal operation for organic Rankine cycle using a machine learning-based radial turbine with variable nozzles at off-design conditions
Authors: Wang Zhiqi , Li Xin , Xia Xiaoxia , Yang Huya , Zuo Qingsong , Xie Baoqi , Gong Tao
Published: February 2025

To maximize the off-design performance of an organic Rankine cycle using a radial turbine with variable nozzles, this study proposes a new integrated optimization method, including design and off-design stages. The one-dimensional design optimization is conducted to simultaneously determine the optimal design parameters and working fluid in a single step. Then, an off-design model of the variable nozzle turbine (VNT) is developed using three-dimensional computational fluid dynamics and particle swarm optimization-backpropagation neural network method to accurately predict its behavior. In addition, the off-design optimization is performed to obtain the optimal off-design performance and operating parameters under constant pressure and sliding pressure control strategy. The results show that R600 is the optimal working fluid among several candidate fluids. The thermal efficiency and net output power of the designed system are 10.91% and 358 kW, respectively. Under the sliding pressure control strategy, the turbine inlet pressure increases linearly while the nozzle outlet angle decreases with increasing heat source temperature, and the isentropic efficiency of the VNT basically maintained at designed value. The influence of heat source temperature on system off-design performance, turbine inlet pressure, and nozzle outlet angle is much greater than that of heat source flow rate. Compared with the constant pressure control strategy, sliding pressure operation can increase the net power of the system by up to 43.9% and reduce the levelized energy cost by 29.2%.
The kinetic mechanism of vortex-cavitation interaction in dual-chamber self-excited oscillation waterjets
Authors: Hou Bowen , Hou Wenjiang , Gao Qiqiang , Wang Yi , Guo Xiaofeng , Fang Zhenlong
Published: February 2025

To explore the kinetic mechanism of vortex-cavitation in self-excited oscillation waterjets, large Eddy simulation was employed to simulate waterjets generated by a Helmholtz nozzle, an organ pipe nozzle, and a dual-chamber nozzle. The deconstruction from vortex energy to cavitation generation mechanisms was accomplished through proper orthogonal decomposition. The vorticity transport equation was used to investigate the relationship between the cavitation cloud in the cleavage state and each of the terms after the corresponding vortex decomposition. The results emphasize the importance of diffusion lip and downstream nozzle length in enhancing the jet capability of the dual-chamber nozzle. Furthermore, the excitation generated by the fluid after modulation through the Organ pipe nozzle significantly enhances the shear capacity of the dual-chamber nozzle jet. The interaction process between vortex-walls in the dual-chamber nozzle is described, with a particular focus on explaining the principle of self-excited oscillation generated by the organ pipe nozzle. The direction of shear vortex rotation represents the area of expansion in the cavitation cloud cluster. The end of the cavitation cloud exchanges energy with the surrounding water, and the expansion and disappearance of the cavitation cloud are directly related to the velocity state of the jet. The waterjets produced by the three types of nozzles have different shear forms to generate cavitation. Compared with waterjets from Helmholtz and organ pipe nozzles, the vapor volume fraction at the center of the dual-chamber nozzle jet increases by 56.3% and 77.6%, respectively, at a distance of 15 times the inlet diameter of the downstream chamber from the outlet.
Initial discontinuity-induced nonphysical oscillations in finite volume method and its suppression algorithm
Authors: Zhang Yue , Su Hongxing , Chen Jie , Wei Yanxin , Liu Jun
Published: February 2025

The finite volume method is widely applied in computational fluid dynamics engineering practices. Particularly in the computation of compressible flow fields, discontinuous structures often evolve into numerical transition zones spanning multiple grid points. During this process, nonphysical oscillations parallel to the discontinuity are generated and are regularly distributed. Discontinuities such as shock waves are defined by characteristic Euler equations, and the UFSC (Upwind Flux Scheme based on Characteristics) scheme is a flux computation method constructed based on the characteristic upwind properties derived from the equations. This paper presents numerical examples comparing the performance of the UFSC scheme with other conventional flux-splitting schemes (such as Steger–Warming, van Leer) under the finite volume method. The results show that the UFSC scheme effectively eliminates the nonphysical oscillations induced by the initial contact discontinuities in the flux vector splitting scheme. Additionally, it significantly reduces the amplitude of the disturbances caused by the initial shock wave. Moreover, for hypersonic flow problems, the UFSC scheme, compared to Roe and other FDS (flux difference splitting) schemes, does not exhibit shock instability, demonstrating excellent numerical stability. The UFSC scheme shows strong stability in both strongly discontinuous and continuous flow fields, demonstrating its practical value in engineering computations.
High-enthalpy unsteady pulsation flow over a double wedge
Authors: Li Sijia , Guo Jinghui , Zhang Qiming , Ma Xinyang , Lai Jingsong
Published: February 2025

Large-scale pulsation unsteadiness is identified in the high-enthalpy shock wave-boundary-layer interaction flow over a double wedge. The objective of the study is to illustrate the transient flowfield evolution and spatiotemporal dynamics of the pulsation mode with vibrational nonequilibrium. A laminar nitrogen flow with a freestream Mach 4.11 and a total enthalpy of 3.77 MJ/kg for a 30°–55° double wedge is considered, which is a test case from the experiments in the Hypervelocity Expansion Tube. Unsteady two-dimensional Navier–Stokes equations incorporating thermochemical nonequilibrium gas model are numerically solved with a due-time stepping time marching scheme to the second-order accuracy. The simulated shock structure agrees well with the experimental Schlieren snapshots in the flow establishment course. Periodic inflation and restoration of the shock system are driven by the expansion of separation bubbles and escape of low-pressure vortices. A single main frequency is identified over the flowfield for the pressure and temperatures, indicating that the motions of the separated region, shock system, and shear layer are strongly coupled to form a synchronized pulsation mode. Finally, the variation in the non-dimensional frequency for high-enthalpy pulsation flow is illustrated based on the binary scaling law.
Multiscale flow structure prediction in unsteady cavitating flow around the hydrofoil
Authors: Yang Dengfeng , Chen Hongxun , Ma Zheng
Published: February 2025

Considering that large eddy simulation (LES) often requires more computational resources to capture small-scale flow characteristics, while the Reynolds-Averaged Navier–Stokes (RANS) methods offers better computational efficiency at the expense of accuracy. The traditional Zwart–Gerber–Belamri cavitation model (Z–G–B) has good universality but insufficiently considers the influencing factors of cavitation. This article proposes a method combining very large eddy simulation (VLES) with the Z–G–B cavitation model (VLES_Z–G–B). However, there remains a certain discrepancies between the predictions and experimental results. To address this, on the basis of the Z–G–B cavitation model, the unsteady cavitation computation method (VLES_Water_Non) is developed, considering the weak compressibility effect of the fluid and incorporating three components: the liquid, vapor, and non-condensable gas. The results indicate that the VLES_Water_Non method compensates for the deficiencies of the VLES_Z–G–B approach, and clarifying that the combined effect of re-entrant flow, side-incident reverse flow, and mainstream are the primary causes of cavity shedding. Using a robust Ω-criterion, multiscale flow features during the cavity evolution process were identified. Additionally, it was found that the vortex stretching and dilation terms are the main reason for the flow separation and formation of complex structures around the hydrofoil. The baroclinic torque term has an significant impact on the generation of vorticity during the shedding process of the cavity. This study is expected to provide a more precise scale resolution method and predictive accuracy for analyzing the internal flow mechanisms of complex fluid machinery.
Modeling energy requirements for oxygen production on the Moon
Authors: Leger Dorian , Ghaffari-Tabrizi Fardin , Shaw Matthew , Rasera Joshua , Dickson David , Valentin Baptiste , Morlock Anton , Thoresen Freja , Cowley Aidan
Published: February 2025

Spacecraft using combustion engines require substantial amounts of oxygen for their propellant. The Moon could be a source of oxygen for rocket propellant, since the material composing the lunar surface can be processed to extract oxygen. However, little is known about overall energy requirements of the processes described in the literature for oxygen extraction from lunar regolith. This knowledge gap constrains the planning of lunar missions, since the scale of energy infrastructure required for oxygen production facilities is not well characterized. This study presents an energy consumption model for oxygen production via hydrogen reduction of the mineral ilmenite (FeTiO
3
). We consider an end-to-end production chain starting from dry regolith as the feedstock. The production includes the following process steps: excavation, transportation, beneficiation, hydrogen reduction, water electrolysis, liquefaction, and zero boil-off storage. The model predicts the energy demand per kilogram oxygen produced based on adjustable parameters for each process step. As expected, the model indicates a strong dependence on feedstock composition. For regolith composed of 10 wt% ilmenite, the model predicts that a total of 24.3 (± 5.8) kWh is needed per kg of liquid oxygen produced. This study confirms that the hydrogen reduction and electrolysis steps have the highest energy requirements in the production chain. Sensitivity analysis reveals that the enrichment factor of the beneficiation process is the most critical parameter for optimizing energy utilization. Overall, this study provides a parameterized end-to-end model of energy consumption that can serve as a foundation for various production systems on the Moon.
Short-term exposure to filter-bubble recommendation systems has limited polarization effects: Naturalistic experiments on YouTube
Authors: Liu Naijia , Hu Xinlan Emily , Savas Yasemin , Baum Matthew A. , Berinsky Adam J. , Chaney Allison J. B. , Lucas Christopher , Mariman Rei , de Benedictis-Kessner Justin , Guess Andrew M. , Knox Dean , Stewart Brandon M.
Published: February 2025

An enormous body of literature argues that recommendation algorithms drive political polarization by creating “filter bubbles” and “rabbit holes.” Using four experiments with nearly 9,000 participants, we show that manipulating algorithmic recommendations to create these conditions has limited effects on opinions. Our experiments employ a custom-built video platform with a naturalistic, YouTube-like interface presenting real YouTube videos and recommendations. We experimentally manipulate YouTube’s actual recommendation algorithm to simulate filter bubbles and rabbit holes by presenting ideologically balanced and slanted choices. Our design allows us to intervene in a feedback loop that has confounded the study of algorithmic polarization—the complex interplay between supply of recommendations and user demand for content—to examine downstream effects on policy attitudes. We use over 130,000 experimentally manipulated recommendations and 31,000 platform interactions to estimate how recommendation algorithms alter users’ media consumption decisions and, indirectly, their political attitudes. Our results cast doubt on widely circulating theories of algorithmic polarization by showing that even heavy-handed (although short-term) perturbations of real-world recommendations have limited causal effects on policy attitudes. Given our inability to detect consistent evidence for algorithmic effects, we argue the burden of proof for claims about algorithm-induced polarization has shifted. Our methodology, which captures and modifies the output of real-world recommendation algorithms, offers a path forward for future investigations of black-box artificial intelligence systems. Our findings reveal practical limits to effect sizes that are feasibly detectable in academic experiments.
The modern pattern of insect herbivory predates the advent of angiosperms by 60 My
Authors: Xiao Lifang , Chen Liang , Labandeira Conrad C. , Azevedo-Schmidt Lauren , Wang Yongjie , Ren Dong
Published: February 2025

Modern ecosystems display complex associations of plants–insects that underwent a long evolutionary process since the appearance of mid-Paleozoic vascular plants. Although several major hypotheses explain the evolution of these plant–insect associations, the initial pattern of modern insect herbivory is poorly understood. To understand the antiquity of modern patterns of terrestrial arthropod herbivory, functional feeding group–damage type (FFG-DT) data were used to analyze a 305 My interval from Late Pennsylvanian to present, in which 134 plant assemblages were used to assess turnover (replacement of some species by other species between sites) and nestedness (difference in composition when no species are replaced between sites) in pairwise comparisons of DTs. Results of beta diversity analyses indicate that the prototype pattern for modern insect herbivory was established on gymnosperm-dominated plant assemblages by late Middle Jurassic, antedating angiosperm dominance by 60 My. Turnover among plant groups and FFGs declined in earlier late Paleozoic, whereas during the later Cenozoic, nestedness generally increased. Insect feeding on gymnosperms showed one pattern of change with low turnover and high nestedness, whereas a bimodal pattern characterized angiosperms. Ferns and angiosperms exhibited less DT functional breadth (host-plant “specificity” by herbivores) than gymnosperms, reflecting major differences in links between insect herbivores and their host plants. This fundamental trophic shift is consistent with the Mid-Mesozoic Parasitoid Revolution, implying top–down control of herbivores by their consumers rather than bottom–up regulation of food sources that shaped the modern herbivory pattern. These findings provide a data-rich account of the ecological origins of modern herbivory.
A limitation lifted: A conditional knockdown system reveals essential roles for Polo-like kinase and Aurora kinase 1 in
Trypanosoma cruzi
cell division
Authors: Wiedeman Justin , Harrison Ruby , Etheridge Ronald Drew
Published: February 2025

While advances in genome editing technologies have simplified gene disruption in many organisms, the study of essential genes requires development of conditional disruption or knockdown systems that are not available in most organisms. Such is the case for
Trypanosoma cruzi
, a parasite that causes Chagas disease, a severely neglected tropical disease endemic to Latin America that is often fatal. Our knowledge of the identity of essential genes and their functions in
T. cruzi
has been severely constrained by historical challenges in very basic genetic manipulation and the absence of RNA interference machinery. Here, we describe the development and use of self-cleaving RNA sequences to conditionally regulate essential gene expression in
T. cruzi
. Using these tools, we identified essential roles for Polo-like and Aurora kinases in
T. cruzi
cell division, mirroring their functions in
Trypanosoma brucei
. Importantly, we demonstrate conditional knockdown of essential genes in intracellular amastigotes, the disease-causing stage of the parasite in its human host. This conditional knockdown system enables the efficient and scalable functional characterization of essential genes in
T. cruzi
and provides a framework for the development of conditional gene knockdown systems for other nonmodel organisms.
Stepwise activation of SARM1 for cell death and axon degeneration revealed by a biosynthetic NMN mimic
Authors: Huang Yinpin , Zhang Jun , Zhang Wenbin , Chen Jie , Chen Sijia , Wu Qincui , Zheng Sanduo , Wang Xiaodong
Published: February 2025

Axon degeneration, driven by the NAD
+
hydrolyzing enzyme SARM1, is an early pathological hallmark of numerous neurodegenerative diseases. SARM1 exists in an inactive form and is activated following nerve injury. However, the precise molecular mechanism underlying SARM1 activation remains to be fully elucidated. In this study, we report the identification of a potent proactivator of SARM1, G10, which is converted into a direct activator (M1) by the enzyme nicotinamide phosphoribosyltransferase. Cryoelectron microscopy structures of SARM1 bound to M1, as well as to M1 and a nonhydrolyzable NAD
+
analog (1AD), captured two intermediate activation states and the fully active state, revealing a stepwise mechanism of SARM1 activation. Further, introducing a disulfide bond to prevent conformational transitions between the two intermediate states mediated by M1 stabilized SARM1 in its inactive form and blocked M1-induced cell death. Together, these findings propose a sequential, stepwise activation model for SARM1 and offer a framework for developing potential SARM1 inhibitors for the treatment of neurodegenerative diseases.
Entre réécriture et réinvention…
Authors: Gęsicka Anna
Published: February 2025

L’objet de cet article est une analyse comparative, à partir d’un instrument théorique proposé par Genette, d’un
célèbre conte du XIIIe siècle, Lai d’Ignauré, avec son adaptation théâtrale
L’Oubliette de Jean Ott, auteur français moins connu (1878–1935). Il offre à son récepteur un jeu
intertextuel intéressant. Le lecteur, dans la « version modèle », serait censé identifier différents niveaux de correspondance
entre deux textes. L’analyse révèle des correspondances multiples et surprenantes au niveau des signes textuels, du lexique, des
noms, des topoïs, des symboles et des idées. Dans le contenu complètement différent de l’adaptation, dans le contexte réinventé,
on trouve des concepts et des motifs repris ou inversés, qui répondent d’une manière ou d’une autre à l’enjeu et au message de
l’hypotexte polysémique et inspirant.
Solar radiation pressure models for BDS-3 IGSO: impacts and improvement from observation geometry
Authors: Yang Chao , Guo Jing , Xu Xiaolong , Wang Longyu , Zhao Qile
Published: February 2025

The orbit quality of BDS-3 inclined geosynchronous orbit (IGSO) satellites is limited by the observation geometry as well as dynamic models. Regarding ground L-band data, the maximum nadir angle for IGSO satellites is approximately 9°. However, with BDS-3 Ka-band inter-satellite link (ISL) data, the maximum nadir angle can reach up to 45°, which significantly improves observation conditions. This study investigates the impact of ISL data on 5-parameter reduced extented CODE orbit model (ECOM1) compared with that from ground L-band data only. It is observed that the estimates of the ECOM1 parameter become more precise by using ISL data, particularly for D
0 as well as those in B direction. Y
0 bias shows noticeable thermal radiation effects for C38 and C39. The Sun-elevation angle dependent clock linear-fit residuals are reduced significantly for C39 or almost vanished for C38 and C40. By analyzing the solar radiation pressure (SRP) accelerations for the solutions with L-band only or L and ISL data, we observed that the radial acceleration differences show opposite dependency with these in the B direction. The similar phenomenon can be observed in the differences of solutions based on ECOM2 and ECOM1 with L-band data only. These reveal that the deficiency of the ECOM1 for the non-cubic satellites can be partly compensated by using better observation geometry from ISL data, as better estimates in B direction can be obtained. Based on the adjustable box-wing model, the optical coefficients of BDS-3 IGSO are calibrated with L-band and ISL measurements. By incorporating these estimates into the box-wing model used as the a priori SRP to augment ECOM1, the Sun-elevation angle dependent errors in clock offsets are mitigated. And the RMS of clock linear-fit is further reduced by approximate 1.2 cm by using the estimates from L-band and ISL data than that from L-band-only data. This demonstrates the positive contribution for ISL on SRP modeling of BDS-3 IGSO satellites.
Numerical simulation of domain wall and first-order phase transition in an expanding universe
Authors: Li Yang , Jia Yongtao , Bian Ligong
Published: February 2025

We numerically study the domain walls (DWs) dynamic through 3D lattice simulation, and show that DWs formed by the breaking of a discrete symmetry in the early Universe can be dissipated by a later cosmic first-order phase transition (PT), even if the DWs have entered the scaling regime. The decay speed of the DWs is characterized by the bubble nucleation rate of the first-order PT. The produced gravitational wave (GW) spectrum can be dominated by the first-order PT and is of a different shape in comparison to that of the DWs. The mechanism can be probed by the current and upcoming GW detectors.
Automatically On-Off Combustion Control for Holding Thermal in Palm Sugar Crystallization Machine
Authors: Aripin H. , Taufikurrahman I. , Sunarya Y. , Busaeri N. , Rizal R. , Sabchevski S.
Published: February 2025

The technology of thermal holding cycles using a combustion ventilation system in the palm sugar crystallization machine has been developed and constructed. The thermal cycles were automatically controlled by sequentially both opening and closing a ventilation system embedded in a sawdust briquette burner. The system doses the amount of flame from the burner to heat the crystal palm sugar in the pan. A control circuit module for the combustion system and a thermocouple in the pan as well as data acquisition software (DAC) for data recording have been implemented. The performance of the prepared combustion control system in the machine was successfully tested by measuring the water content of sugar crystals. It has been found that crystal sugar with the best water content, reaching the standard of 2.7% has been produced by holding the heating temperature at 70°C for 22 minutes. The conclusion of this study is that the thermal holding cycles using the combustion control system are suitable technological equipment for heating palm crystal sugar and are characterized by at least three advantages, namely precise control and shorter heating time, as well as higher sugar product quality.