bluuebunny/crossref_metadata_2025 huggingface dataset:
Multimodal mechanisms of human centriole engagement and disengagement
Authors: Ito Kei K , Takumi Kasuga , Matsuhashi Kyohei , Sakamoto Hirokazu , Nagai Kaho , Fukuyama Masamitsu , Yamamoto Shohei , Chinen Takumi , Hata Shoji , Kitagawa Daiju
Published: February 2025

Centrioles are unique cellular structures that replicate to produce identical copies, ensuring accurate chromosome segregation during mitosis. A new centriole, the “daughter”, is assembled adjacent to an existing “mother” centriole. Only after the daughter centriole is fully developed as a complete replica, does it disengage and become the core of a new functional centrosome. The mechanisms preventing precocious disengagement of the immature daughter centriole have remained unclear. Here, we identify three key mechanisms maintaining mother–daughter centriole engagement: the cartwheel, the torus, and the pericentriolar material (PCM). Among these, the torus critically establishes the characteristic orthogonal engagement. We also demonstrate that engagement mediated by the cartwheel and torus is progressively released during centriole maturation. This release involves structural changes in the daughter, known as centriole blooming and distancing, respectively. Disrupting these structural transitions blocks subsequent steps, preventing centriole disengagement and centrosome conversion in the G1 phase. This study provides a comprehensive understanding of how the maturing daughter centriole progressively disengages from its mother through multiple steps, ensuring its complete structure and conversion into an independent centrosome.
Qualitative and quantitative analyses of the changes in the chemical composition of frankincense before and after stir-frying using GC-MS and LC-MS
Authors: Shi Aiwen , Tang Xiaolei , Liu Li , Qi Bin , Wang Chang , Jia Ziyi
Published: February 2025

Frankincense is a resin drug used widely in the medical field.
Zwitterionic polymer with minimal reactivity against PEG antibodies to enhance the therapeutic effects of cytokine-targeting DNA aptamer
Authors: Cho Seojung , Hori Miyuki , Ueki Ryosuke , Saito Yutaro , Nagai Yukiko , Iki Haruka , Tsuchiya Akira , Konno Tomohiro , Owari Kensuke , Piao Haishun , Futami Kazunobu , Sando Shinsuke
Published: February 2025

Zwitterionic polymer PMPC was conjugated to a DNA aptamer to enhance its therapeutic efficacy in vivo, while minimizing the recognition by anti-PEG antibodies.
An extended π-conjugated bipolar polymer cathode for rechargeable magnesium batteries: high capacity contributed by n- and p-doping and charge delocalization
Authors: Cui Shuai , Qin Zhen , Gui Hongda , Li Ting , Zhang Daohong , Xu Fei
Published: February 2025

An extended conjugated bipolar polymer cathode is developed for rechargeable magnesium batteries, which undergoes p- and n-doping with enhanced charge delocalization. The extended conjugated structure guarantees high capacity and cycling stability.
Chemical tools for probing histidine modifications
Authors: Bilgin Nurgül , Hintzen Jordi C. J. , Mecinović Jasmin
Published: February 2025

This feature article highlights the application of chemical tools for understanding and manipulating the histidine residues in proteins.
Click and shift: the effect of triazole on solvatochromic dyes
Authors: Rouillon Jean , Benitez-Martin Carlos , Grøtli Morten , Andréasson Joakim
Published: February 2025

Azido-functionalised push–pull fluorenes, modified via CuAAC, show triazole-induced emission shifts and enhanced photophysical properties. These findings enable the synthesis of high-performance fluorosolvatochromic dyes for diverse applications.
High-resolution leak-out spectroscopy of HHe2+
Authors: Salomon Thomas , Baddeliyanage Carlo , Schladt Carla , Simkó Irén , Császár Attila G. , Silva Weslley G. D. P. , Schlemmer Stephan , Asvany Oskar
Published: February 2025

Applying a novel and universal action spectroscopic technique, called leak-out spectroscopy, this paper revisits the ν3 proton shuttle motion of the symmetric linear molecule He–H+–He.
An isotope dilution approach for validating the output of mercury gas generators for mercury pollution monitoring
Authors: Page Sophie , Dunn Philip J. H. , Petrov Panayot , Nair Sreekanth Vijayakumaran , Živković Igor , Horvat Milena , Corns Warren T. , Goenaga-Infante Heidi
Published: February 2025

The outputs of Hg0 and HgII gas generators were validated by isotope dilution with a dynamically generated 199Hg enriched gas standard produced by continuous cold vapour and ICP-MS detection, thereby providing SI-traceability with primary standards.
Thermal evolution of solid solution of silica-embedded AgPt alloy NPs in the large miscibility gap
Authors: Jatav Hemant , Chakravorty Anusmita , Mishra Ambuj , Schwartzkopf Matthias , Chumakov Andrei , Roth Stephan V. , Kabiraj Debdulal
Published: February 2025

This work features the temperature-dependent growth kinetics of silica-embedded AgPt alloy NPs, focusing on maintaining ultrasmall NP size and nanoalloy phase stability for high-temperature catalytic applications.
Tunable magnetoelectricity and polarity in van der Waals antiferromagnetic CuCr1−xFexP2S6
Authors: Xing Yu , Ye Haoshen , Du Guowei , Li Xu , Miao Le-Ping , Zhang Junchao , Luo Xiong , Chen Xiyu , Ye Haoran , Shen Aoli , Wang Zhicheng , You Yumeng , Dong Shuai , Li Linglong
Published: February 2025

Magnetoelectricity coupling is realized in the van der Waals CuCrP2S6 system by doping.
Nanofiber-shaped Co3O4@In2O3 composite for high-performance enzymeless glucose sensing
Authors: Xu Xinda , Zhang Chao , Yang Woochul , Li Yujia , Li Bing , Haldorai Yuvaraj , Zhenyu Jiang , Xie Wanfeng
Published: February 2025

The accompanying figure illustrates the preparation process (electrostatic spinning and hydrothermal), sensing principle and performance testing (cyclic voltammetry and current–time measurements) of the glucose sensor mentioned in this paper.
Microwave-assisted synthesis of mesoporous high-entropy alloy and core–shell nanoparticles
Authors: Ni Chuyi , Guo Suni , Butler Cole , Veinot Jonathan G. C.
Published: February 2025

Mesoporous high-entropy alloy core-shell nanoparticles (Au-RhAgCuPdPt) can be synthesized via microwave-assisted heating. Their thermal conversion to high-entropy alloy nanoparticles (AuRhAgCuPdPt) were further invesitgated by in situ heating TEM.
Fe-doped Ni3S2/NiS heterojunction with improved electrocatalytic activity and stability for the alkaline oxygen evolution reaction
Authors: Sun Jiening , Miao Licheng , Xu Zhichuan J. , Sun Zhipeng
Published: February 2025

The heterostructure catalyst Fe-Ni3S2/NiS exhibits excellent activity and stability. The doped Fe acts as a sacrificial agent in the oxygen evolution reaction (OER), maintaining the high activity of Ni, and preventing the Ni–S bond degradation.
Three-component synthesis of β-sulfonyl enamines and dienamines enabled by silver(i) acetate
Authors: Koudelka Jakub , Tobrman Tomáš
Published: February 2025

The three-component synthesis of β-sulfonyl enamines and δ-sulfonyl dienamines is achieved by silver acetate-mediated condensation of secondary and tertiary amines with sodium sulfinates.
Leveraging self-passivation of quantum dots via nitrogen-doping for multifunctional biopolymer nanocomposites
Authors: Tuccitto Anthony V. , Aguiar Rafaela , Sansone Nello D. , Chehrehsaz Yalda , Kumral Boran , Serles Peter , Filleter Tobin , Park Chul B. , Lee Patrick C.
Published: February 2025

N-doped QDs offer unique blue-light/UV-blocking, crystal nucleation, lubricating and toughening effects.
Selective alkylation of phenol and tert-butanol using Zr-containing Beta zeolite
Authors: Jiang Huoyan , Zhang Zhuo , Li Xin , Zeng Xingxing , Pu Ting , Liu Baoyu
Published: February 2025

Zr-containing Beta nanocrystals show the desired selectivity toward 2,4-DTBP based on the transformation of 4-TBP.
Synergistic integration of polysulfobetaine brush-grafted porphyrinic covalent organic frameworks with native enzymes for electrolyte-sensitive aerobic photobiocatalysis
Authors: Xiang Qian , Meng Ze Peng , Li Xue , Zhang Bin , Xuan Fu-Zhen , Cai Tao
Published: February 2025

COFs with polysulfobetaine brushes (TpDh-P) could efficiently regenerate NAD+ from NADH under red light. The polysulfobetaines brushes capture and neutralize ROS, protecting native enzymes, and modulate NADH oxidation with electrolyte-sensitivity.
Field analysis of directionality measurement with inverter based resources in India
Authors: Shyamaprasad Ashoka , Vittal K. P. , AN Praveen , Naidu O. D.
Published: February 2025

Renewable energy sources are getting integrated into the electrical power network since many years. The characteristics of these sources are completely different from traditional synchronous generators. This is posing challenges for power engineers from system protection and control perspective. Cases of maloperations of protective relays have been a focus of research across industries and universities. India has been growing in deploying distributed energy resources. Most of the maloperations reported relate to transmission line protection. Studies on maloperation of directional element are not duly addressed from Indian grid perspective. Few cases from India have been chosen for research. Fault data from Type‐4 and Type‐3 wind plant and solar park has been analysed and compared with literature reports. The objective of this paper is to document the behaviour of directional elements for a distributed energy resource connected system in India. In addition, aim is to understand the gaps from existing research to the behaviours of the current directional protections. This would help in identifying mechanisms to ascertain directionality for similar systems in the future. The conclusion from the paper is that the detection of fault direction must be completed before the time inverter control kicks in to operation in any algorithm.
Radial dependence of solar energetic particle peak fluxes and fluences
Authors: Cao Yihang , Wang Yubao , Guo Jingnan
Published: February 2025

Context. We present a list of solar energetic particle (SEP) events detected by instruments on board the Solar and Heliospheric Observatory (SOHO), Parker Solar Probe (PSP), and Solar Orbiter between 2021 and 2023. The investigation focuses on identifying the peak flux and the fluence of SEP events in four energy ranges from 10.5 to 40 MeV, as observed by PSP or Solar Orbiter at heliospheric distances shorter than 1 AU and by SOHO at the Sun-Earth L1 Lagrangian point.

Aims. Based on the data from these events, we conduct a statistical analysis to study the radial dependence of the SEP proton peak flux and fluence at different energies.

Methods. We identified 42 SEP events with enhanced proton flux that were observed simultaneously by at least two out of three spacecraft (SOHO, PSP, and Solar Orbiter). These events were further selected based on a criterion of a difference smaller than a 30° difference in longitudinal separation between the magnetic footpoints of the two spacecraft. For the selected events, we used a linear interpolation method to compute the proton peak flux and fluence in four energy ranges and quantified their radial dependence as a function of Rα, where R is the radial distance of the observer from the Sun.

Results. The peak flux and fluence of the SEP events display the following radial dependence: The average values of α across all energies range between about −3.7 and −2 for the peak fluxes and between −2.7 and −1.4 for the fluences. We also obtained the energy dependence of |α|, which decreases with increasing energy. Additionally, based on theoretical functions, we find that the SEP source and transport parameters may have a significant impact on α(E), and the measurement-derived |α(E)| values and their distribution fall within the range of theoretical predictions.

Conclusions. (1) Despite the uncertainties arising from the low statistics and the longitudinal influence, the radial dependence of the peak flux agrees with the upper limit R−3 predicted by previous studies. (2) The radial dependence on the fluence R−2 tends to be weaker than the radial decay of the peak flux. (3) As the proton energy increases, the proton mean free path increases, and the adiabatic cooling effect modifies the proton energy. As a result, the peak flux and fluence decay more significantly with increasing radial distance for lower-energy particles.
A novel method for estimating the far-ultraviolet flux, and a catalogue for star-hosting discs in nearby star-forming regions
Authors: Anania Rossella , Winter Andrew J. , Rosotti Giovanni , Vioque Miguel , Zari Eleonora , Pantaleoni González Michelangelo , Testi Leonardo
Published: February 2025

When protoplanetary discs are externally irradiated by far-ultraviolet (FUV) photons from OBA-type stars, they lose material through photoevaporative winds. This reduces the amount of material that is available to form planets. Understanding the link between the environmental irradiation and the observed disc properties requires accurately evaluating the FUV flux at star-hosting discs, which can be challenging because of the uncertainty in stellar parallax. We addressed this issue by proposing a novel approach: using the local density distribution of a star-forming region (i.e. 2D pairwise star separation distribution) and assuming isotropy, we inferred the 3D separation between star-hosting discs and massive stars. We tested this approach on synthetic clusters and showed that it significantly improves accuracy compared to previous methods. We computed the FUV fluxes for numerous star-bearing discs in seven regions within ∼200 pc, six regions in Orion and in Serpens sub-regions. We provided a publicly accessible catalogue. We found that discs in regions hosting late-type B and early-type A stars can reach non-negligible FUV radiation levels for the disc evolution (10-100 mathrm G ). We investigated dust disc masses relative to FUV fluxes and detected indications of a negative correlation when we restricted the investigation to average region ages. However, we emphasize the need for more stellar and disc measurements at >$10^ G $ to probe the dependence of disc properties on environmental irradiation. The method presented in this work is a powerful tool that can be expanded to additional regions.
Molecular gas and dust properties in z > 7 quasar hosts
Authors: Salvestrini Francesco , Feruglio Chiara , Tripodi Roberta , Fontanot Fabio , Bischetti Manuela , De Lucia Gabriella , Fiore Fabrizio , Hirschmann Michaela , Maio Umberto , Piconcelli Enrico , Saccheo Ivano , Tortosa Alessia , Valiante Rosa , Xie Lizhi , Zappacosta Luca
Published: February 2025

Observational campaigns hunting the elusive reservoirs of cold gas in the host galaxies of quasars at the epoch of reionization (EoR) are crucial for studying the formation and evolution of the first massive systems at early epochs. We present new Northern Extended Millimeter Array (NOEMA) observations tracing CO(6–5) and CO(7–6) emission lines as well as the underlying continuum in five of the eight quasars at redshift z > 7 known to date, thus completing the survey of the cold molecular gas reservoir in the host galaxies of the first quasars. Combining NOEMA observations with archival Atacama Large Millimeter/submillimeter Array (ALMA) data, we modeled the far-infrared spectral energy distribution with a modified blackbody function to measure dust properties and star formation rates. We used CO and [CII] lines to derive molecular gas masses, which we compared with results from semi-analytic models and observations of galaxies at different epochs. No statistically significant detection of CO emission lines was reported for the five quasars in this sample, resulting in a relatively low amount of cold molecular gas in the host when compared with galaxies at later epochs. Nonetheless, gas-to-dust ratios are consistent with the local value, suggesting that the scaling relation between dust and cold gas holds up to z > 7. Quasars at the EoR show star formation efficiencies that are among the highest observed so far and comparable with those observed in luminous quasars at Cosmic Noon and those predicted for the brightest (Lbol > 3 × 1046 erg s−1) quasar objects drawn from the semi-analytic model GAEA. Quasar host galaxies at the EoR are undergoing an intense phase of star formation, which suggests a strong coupling between the luminous phase of the quasar and the rapid growth of the host.
Critical-current degradation in superconducting niobium–titanium alloys in external magnetic fields under a load
Authors: Boiko V. S. , Lazareva M. B. , Starodubov Ya. D. , Chernyi O. V. , Gorbatenko V. M.
Published: February 2025

The effect of external magnetic fields on the stress at which critical-current degradation starts (degradation threshold σ0e) under the action of a mechanical load in superconducting niobium–titanium alloys was studied and a possible mechanism for the observed effect is proposed. It is conjectured that the additional stresses which are exerted on a transformation dislocation by external magnetic fields, stimulate growth of martensitic inclusions whose superconducting parameters (critical–current density jc and critical temperature Tc) are lower than in the starting material. The degradation threshold in external magnetic fields (intensity H up to 7 T) was investigated experimentally. The observed field dependence σ0e(H) it is shown that external magnetic fields play a significant role in critical-current degradation at the initial stages of deformation. This feature confirms the conjecture that the load-induced degradation of the superconducting parameters is caused by the phenomenon of superelasticity—reversible change in the size of martensite inclusions under a load—and not by reversible mechanical twinning. It is conjectured that the results obtained are important for judging the stability of supercondcuting solenoids operating over a wide range of magnetic fields.
Rydberg excitations in neon cryogenic crystals
Authors: Belov A. G. , Fugol’ I. Ya. , Yurtaeva E. M.
Published: February 2025

The energy spectrum of single-center Rydberg excitations of O, N, C, and H and characteristic autolocalized states in a neon matrix was investigated. The general structural regularities of single-center states, which characterize the interaction of the states with the lattice, were determined. The effect of the lifetime and radius of an excited atom on the structure of the emitting centers was examined. The development of the inelastic restructuring of the lattice in the nearest-neighbor environment of the excitation is analyzed on the basis of the deformation-interaction model.
Tunneling investigations of superconducting Bi–Pb–Sr–Ca–Cu–O films with T
c = 100 K
Authors: Arutyunyan S. R. , Saakyan S. R. , Pilosyan S. Kh.
Published: February 2025

The current-voltage characteristics of a tunnel contact based on high-Tc, superconducting films with the composition Bi–Pb–Sr–Ca–Cu–O were investigated in the temperature range 11–110 K. Measurements of the voltage dependences (dI/dU) (U) and dU/dI) (U) gave the following values for the energy gap width: Δ = 19 meV, 2Δ /kTc = 5.5 for the 80 K phase and Δ = 36 meV, 2Δ /kTc = 2.59 for the 110 K phase.
Temperature-dependent point-contact characteristics of some granular high-T
c superconductors
Authors: Hohn N. , Wohlleben D. , Schmidt H. , Seidler F.
Published: February 2025

We report I-V characteristics of point contact with sintered pellets of YBa2(Cu0.96Co0.04)O7–δ and of BiPb0.2SrCaCu2O5.7 between 4.2 and 80 K. The prominent quasiperiodic spikes, which often appear in the differential resistance of such contacts at low temperatures, can be interpreted as geometric resonances within small crystallites, which are enclosed entirely by defect surfaces with high coefficients of reflection. The resonances appear when the thermal coherence length hvF/kBT becomes larger than the spacing between the defect surfaces. The energy spacings and the temperature of appearance of the spikes are consistent with the large Fermi velocities and the large radii of curvature of the Fermi surface found by band structure calculations in the CuO planes.
Water “diode” blocks waves but not boats
Authors: Patrick Chris
Published: February 2025

A unidirectional wave blocker could enhance the efficiency of harbors.
Designing a safer parachute
Authors: Daniel Hannah
Published: February 2025

Simulations of radially closed parachutes reveal the flow dynamics of their advantageous structures
Micromagnetic simulation of Nd–Fe–B grain with a dysprosium-containing shell
Authors: Li Kai , Dai Yingying , Dai Zhiming , Wang Zhenhua , Li Da , Liu Wei , Zhang Zhidong
Published: February 2025

The effects of Dy-doped shell thickness on the magnetic properties and magnetization reversal behavior of a Nd–Fe–B grain have been systematically investigated using micromagnetic simulations based on a core–shell model. The Dy-containing shell can significantly enhance the coercivity of the model. Notably, when the shell thickness reaches 12 nm, the coercivity reaches its maximum value, and the nucleation sites shift from the core–shell interface to the grain corners. Ferromagnetic resonance spectra indicate that the low-frequency modes are associated with the nucleation sites, and the increased coercivity is related to the shift of the core–shell simultaneous resonance mode to higher frequency. In addition, we propose a multi-shell model to further enhance the coercivity by shifting the nucleation points. This approach of adjusting the nucleation sites can also be applied to improve the magnetic properties of other magnets.
Biosensors integrated within wearable devices for monitoring chronic wound status
Authors: Szunerits Sabine , Boukherroub Rabah , Kleber Christoph , Knoll Wolfgang , Yunda Jhonny , Rumipamba José , Torres Guido , Melinte Sorin
Published: February 2025

Slowly healing wounds significantly affect the life quality of patients in different ways, due to constant pain, unpleasant odor, reduced mobility up to social isolation, and personal frustration. While remote wound management has become more widely accepted since the COVID-19 pandemic, delayed treatment remains frequent and results in several wound healing related complications. As inappropriate management of notably diabetic foot ulcers is linked to a high risk of amputation, effective management of wounds in a patient-centered manner remains important to be implemented. The integration of diagnostic devices into wound bandages is under way, owing to advancements in materials science and nanofabrication strategies as well as innovation in communication technologies together with machine learning and data-driven assessment tools. Leveraging advanced analytical approaches around local pH, temperature, pressure, and wound biomarker sensing is expected to facilitate adequate wound treatment. The state-of-the-art of time-resolved monitoring of the wound status by quantifying key physiological parameters as well as wound biomarkers' concentration is presented herewith. A special focus will be given to smart bandages with on-demand delivery capabilities for improved wound management.
Perturbation energy extraction from a fluid via a subsurface acoustic diode with sustained downstream attenuation
Authors: Schmidt R. , Yousef H. , Roy I. , Scalo C. , Nouh M.
Published: February 2025

Engineered subsurface structures inspired by phononic materials have shown favorable capabilities in flow control. Current efforts rely on tuning a structural resonance to the frequency of an unstable fluid mode, causing the deformations of the interfacing solid to destructively interfere with a wave-like flow instability. Although promising, the technique is most effective at targeting a single frequency mode with high-Q resonance. Additionally, several studies have shown the reduction in the perturbation energy to be spatially localized to the flow region above the subsurface strip, with a severely worsening effect downstream. Motivated by a desire to overcome these limitations, we present a different approach to methodically extract an undesirable pressure disturbance from a fluid column in a manner that capitalizes on the broad frequency range of a phononic bandgap, with the goal of permanently confining the perturbation energy within the subsurface structure. An acoustic diode (AD), i.e., a unidirectional transmitter of mechanical energy, comprised of a bi-layered phononic crystal and an auxiliary medium, interacts with a fluid cavity and provides a terminal energy sink. Two distinct ADs are presented that demonstrate active (time-variant) and passive (strain-dependent) paths to concept realization. The AD’s performance is described in terms of the time-transient energy distribution in the fluid and the interacting structure, as well as spatial wave profiles at critical time instants. The results show the system’s ability to achieve robust extraction of undesirable fluid oscillations with minimal residual energy. The concept is then tested in a fully developed plane channel flow with a superimposed perturbation, demonstrating the sustained nature of the subsurface AD’s energy trapping mechanism in addition to its ability to induce downstream attenuation.
Defect-induced modification of electronic and optical properties of CeO2 unveiled by many-body Green’s function theory
Authors: Zhang Mengyu , Song Yiting , Jiang Ya-nan , Ma Yuchen
Published: February 2025

We explore the impact of point defects, including oxygen vacancies (Ov), cerium interstitials (Ce-int), and hydroxyl groups (Hy), on the electronic and optical properties of bulk CeO2 using many-body Green’s function theory (GW method and Bethe–Salpeter equation). Although these three defects all produce occupied electronic levels near the conduction band minimum, they impose quite different effects. Ov and Ce-int induce strong peaks in the low-energy region of the imaginary part of the microscopic dielectric function, indicating stronger electronic screening compared to the pristine CeO2. This causes pronounced narrowing of the bandgap, e.g., by 0.8 eV in G0W0 and 1.6 eV in the eigenvalue self-consistent GW for Ov. Comparatively, Hy affects little electronic screening and bandgap at different levels of GW calculations. For the lowest several 4f orbitals, the exchange part of the self-energy (|Σx| > 9 eV) in GW is much stronger than the correlation part (|Σc| < 5 eV) for Ov and Ce-int, while |Σc| is much stronger than |Σx| instead for the pristine CeO2 and Hy. Quasiparticle weights in Ov and Ce-int decrease by a large quantity compared to the pristine CeO2. Consideration of Ov and Ce-int might to some extent relieve the discrepancy between the GW bandgap of the pristine CeO2 and the experimental gap. Ov and Ce-int could reduce the excitonic binding energy several times and result in optical absorption, which corresponds to the experiments.
Bridging multifluid and drift-diffusion models for bounded plasmas
Authors: Gangemi G. M. , Alvarez Laguna A. , Massot M. , Hillewaert K. , Magin T.
Published: February 2025

Fluid models represent a valid alternative to kinetic approaches in simulating low-temperature discharges: a well-designed strategy must be able to combine the ability to predict a smooth transition from the quasineutral bulk to the sheath, where a space charge is built at a reasonable computational cost. These approaches belong to two families: multifluid models, where momenta of each species are modeled separately, and drift-diffusion models, where the dynamics of particles is dependent only on the gradient of particle concentration and on the electric force. It is shown that an equivalence between the two models exists and that it corresponds to a threshold Knudsen number, in the order of the square root of the electron-to-ion mass ratio; for an argon isothermal discharge, this value is given by a neutral background pressure Pn≳1000 Pa. This equivalence allows us to derive two analytical formulas for a priori estimation of the sheath width: the first one does not need any additional hypothesis but relies only on the natural transition from the quasineutral bulk to the sheath; the second approach improves the prediction by imposing a threshold value for the charge separation. The new analytical expressions provide better estimations of the floating sheath dimension in collisions-dominated regimes when tested against two models from the literature.
Spontaneous formation of potential cascade enhances charge separation in PM6-Y6 organic photovoltaics
Authors: Tamura Hiroyuki
Published: February 2025

Mechanisms that enhance charge separation at donor–acceptor interfaces are the key to material design of non-fullerene electron acceptors for high-efficiency organic photovoltaics (OPV). Here, the energetics of charge separation at the PM6-Y6 donor–acceptor interface in the state-of-the-art OPV is analyzed on the basis of quantum mechanics/molecular mechanics calculations. The electron energy level in Y6 becomes lower with increasing distance from the interface with PM6 at which the crystallinity is lower than in the bulk region. Electrostatic interactions from the multipoles of Y6 stabilize the electron in the crystalline region. The PM6-ITIC donor–acceptor interface also exhibits a similar potential cascade owing to the quadruple of ITIC. The potential cascade destabilizes charge transfer states at the PM6-Y6 interface, thereby decreasing the potential barrier for charge separation. Charge delocalization on several molecules via transfer integral further decreases the barrier for charge separation.
Atomistic analysis of nematic phase transition in 4-cyano-4′-n-alkyl biphenyl liquid crystals: Sampling for the first-order phase transition and the free-energy decomposition
Authors: Ogita Shunsuke , Ishii Yoshiki , Watanabe Go , Washizu Hitoshi , Kim Kang , Matubayasi Nobuyuki
Published: February 2025

Molecular dynamics simulations were conducted using the generalized replica exchange method (gREM) on the 4-cyano-4′-n-alkyl biphenyl (nCB) system with n = 5, 6, 7, and 8, which exhibits a nematic–isotropic (NI) phase transition. Sampling near the phase transition temperature in systems undergoing first-order phase transitions, such as the NI phase transition, is demanding due to the substantial energy gap between the two phases. To address this, gREM, specifically designed for first-order phase transitions, was utilized to enhance sampling near the NI phase transition temperature. Free-energy calculations based on the energy representation (ER) theory were employed to characterize the NI phase transition. ER evaluates the insertion free energy of the nCB molecule for both nematic and isotropic phases, revealing a change in the temperature dependence across the NI phase transition. Further decomposition into energetic and entropic terms quantitatively shows the balance between these contributions at the NI phase transition temperature.
Time-reversal symmetry in RDMFT and pCCD with complex-valued orbitals
Authors: Rodríguez-Mayorga Mauricio , Loos Pierre-François , Bruneval Fabien , Visscher Lucas
Published: February 2025

Reduced density matrix functional theory (RDMFT) and coupled cluster theory restricted to paired double excitations (pCCD) are emerging as efficient methodologies for accounting for the so-called non-dynamic electronic correlation effects. Up to now, molecular calculations have been performed with real-valued orbitals. However, before extending the applicability of these methodologies to extended systems, where Bloch states are employed, the subtleties of working with complex-valued orbitals and the consequences of imposing time-reversal symmetry must be carefully addressed. In this work, we describe the theoretical and practical implications of adopting time-reversal symmetry in RDMFT and pCCD when allowing for complex-valued orbital coefficients. The theoretical considerations primarily affect the optimization algorithms, while the practical implications raise fundamental questions about the stability of solutions. In particular, we find that complex solutions lower the energy when non-dynamic electronic correlation effects are pronounced. We present numerical examples to illustrate and discuss these instabilities and possible problems introduced by N-representability violations.
Low-voltage operation mode of ASCENT-propelled pulsed plasma thruster
Authors: Organski Lee , Jeffers Brian , Gresham Patrick , Kucharewicz Artur , Shashurin Alexey
Published: February 2025

This study demonstrates the feasibility of operating a liquid-fed pulsed plasma thruster (PPT) at low voltages, in the magnetoplasmadynamic (MPD) arc range below 100 V, in contrast to conventional PPTs operating in the kV range. The system uses ASCENT (Advanced Spacecraft Energetic Nontoxic Propellant) as a propellant. Low voltage operation was achieved by eliminating long discharge electrodes and associated voltage drops. The designed thruster demonstrated consistent operation at discharge voltages of 50–150 V for discharge currents varying in the range of 2–8 kA. The measured V–I characteristics of the thruster’s discharge were consistent with self-field MPD arcs, and, correspondingly, the designed system can be classified as a pulsed-MPD thruster. We further confirmed the action of the accelerating Lorentz force on the propellant by measuring fast exhaust ion velocities in the range of 10–30 km/s. Photographic observations confirmed the formation of a plasma jet sourced from the ASCENT propellant, with minimal cathode spot formation, supporting that reduced cathode erosion and the system’s long operational lifetime can be expected. The designed ASCENT-propelled PPT can be utilized as an electric propulsion mode in a dual-mode propulsion system combining chemical and electric propulsion modes.
Thermoelectric algebra made simple for thermoelectric generator module performance prediction under constant Seebeck coefficient approximation
Authors: Ryu Byungki , Chung Jaywan , Park SuDong
Published: February 2025

Although thermoelectric material performance can be estimated using the dimensionless figure of merit ZT, predicting the performance of thermoelectric generator modules (TGMs) is complex owing to the nonlinearity and nonlocality of the thermoelectric differential equations. Here, we present a simplified thermoelectric algebra framework for predicting TGM performance within the constant Seebeck coefficient approximation (CSA). First, we revisit the constant Seebeck coefficient model (CSM) to transform the differential equations into exact algebraic equations for thermoelectric heat flux and conversion efficiency in terms of the load resistance ratio and relative Fourier heat flux. Next, we introduce the CSA, where the Thomson term is neglected and the device parameters are assumed to be fixed. We define the average thermoelectric properties and device parameters under the zero-current condition using a simple temperature integral. Finally, we derive approximate thermoelectric algebraic equations for voltage, resistance, heat flux, and conversion efficiency as functions of current. We numerically validate that the CSA formalism is superior to other single-parameter theories, such as peak-ZT, integral-ZT, and generic engineering-ZT, in predicting efficiency. The relative standard error of the optimal efficiency is less than 11% for average ZT values not exceeding 2. By combining the CSM and CSA, TGM performance can be easily estimated without requiring calculus or solving differential equations. Therefore, this simplified thermoelectric algebra under the CSA framework has the potential to significantly enhance future TGM analysis and design, facilitating more efficient device-level research and development beyond the traditional focus on material properties.
Tuning the magnetic properties by partial substitution of Cr in D022-Mn3Ga: A potential material for spin transfer torque applications
Authors: Perween Sonam , Gahtori Bhasker , Mohapatra Niharika
Published: February 2025

This report presents the effect of partial substitution of the Cr atom at the itinerant octahedral site (Y2b site) of D022-type Mn3Ga. The Cr introduces a reduction of magnetization due to the antiparallel alignment of Cr atoms at the itinerant site to Mn atoms at the localized site (X4d) with variation in mixed valence states (Mn4+ and Mn3+) from that of the pristine as revealed from the deconvolution of the Mn2p peak. The alloy possesses irreversible magneto-structural phase transformation during heating and cooling modes of temperature-dependent magnetization study. During heating, the magnetic interaction between Mn and Cr atoms possesses an abrupt change in magnetization over temperature, leading to Hopkinson’s like effect with magneto-structural transition temperature (Tc) ∼ 780 K, notably higher than the parent alloy. The thermal variation of uniaxial magnetocrystalline anisotropy ≈1.20-0.2 Merg/cc in addition to high coercivity (∼1.2–2.85 kOe) can be utilized as potential material for spin transfer torque-based memory applications.
Structural refinement and magnetic tuning in cobalt-substituted SrFe12O19 hexaferrite
Authors: Moatoshi  , Borgohain C. , Kaushik S. D. , Borah J. P.
Published: February 2025

In this study, we synthesize strontium hexaferrite (SrFe12O19, SrM) with transition metal substitution cobalt (SrFe12−xCoxO19, SrCoM) with weight percentage (x = 3%, 5%, and 7%) through a chemical co-precipitation approach. The hexaferrite phase (P63/mmc) along with a small amount of secondary phase identified as hematite (α-Fe2O3) and halite (NaCl) were found from the x-ray diffraction analysis. A three-phase Rietveld refinement using FullProf software was used to evaluate the average bond lengths and angles, offering important information on superexchange interactions’ impact inside the lattice. The magnetic ordering and crystal structure were also analyzed using neutron powder diffraction and the produced samples showed a ferrimagnetic arrangement at ambient temperature. The crystal structure, magnetic parameters, and maximal energy product (BH)max of the synthesized materials were found to be considerably affected by cobalt substitution: post-substitution, coercivity increases, while saturation magnetization and retentivity decrease. The present work emphasizes the potential of strontium hexaferrite and its cobalt-substituted derivatives as attractive magnetic materials for diverse magnetic applications.
Potential distribution theory of alchemical transfer
Authors: Azimi Solmaz , Gallicchio Emilio
Published: February 2025

We present an analytical description of the Alchemical Transfer Method (ATM) for molecular binding using the Potential Distribution Theory (PDT) formalism. ATM models the binding free energy by mapping the bound and unbound states of the complex by translating the ligand coordinates. PDT relates the free energy and the probability densities of the perturbation energy along the alchemical path to the probability density at the initial state, which is the unbound state of the complex in the case of a binding process. Hence, the ATM probability density of the transfer energy at the unbound state is first related by a convolution operation of the probability densities for coupling the ligand to the solvent and coupling it to the solvated receptor—for which analytical descriptions are available—with parameters obtained from maximum likelihood analysis of data from double-decoupling alchemical calculations. PDT is then used to extend this analytical description along the alchemical transfer pathway. We tested the theory on the alchemical binding of five guests to the tetramethyl octa-acid host from the SAMPL8 benchmark set. In each case, the probability densities of the perturbation energy for transfer along the alchemical transfer pathway obtained from numerical calculations match those predicted from the theory and double-decoupling simulations. The work provides a solid theoretical foundation for alchemical transfer, offers physical insights on the form of the probability densities observed in alchemical transfer calculations, and confirms the conceptual and numerical equivalence between the alchemical transfer and double-decoupling processes.
Mechanism of polymer molecular weight-dependent suppression and promotion of liquid–liquid phase separation of a protein solution by the addition of polymer
Authors: Osaka Yoshihiro , Okamoto Ryuichi , Sumi Tomonari , Koga Kenichiro , Imamura Hiroshi , Shirai Tsuyoshi , Isogai Yasuhiro
Published: February 2025

Polyethylene glycol (PEG) is a widely used precipitant to concentrate proteins. The effect of PEG is generally understood to be an entropic attraction between proteins due to the depletion effect of PEG around proteins. However, measurements by Bloustine et al. [Phys. Rev. Lett. 96, 087803 (2006)] of the liquid–liquid phase separation (LLPS) temperature have shown that a lysozyme solution is stabilized and destabilized by the addition of low and high molecular-weight PEG, respectively. They also presented a theoretical model of the LLPS temperature as a virial expansion of the free energy and concluded that, in addition to the depletion effect, the attractive interaction between protein and PEG is necessary to explain the experiments. In the present study, theoretical calculations based on liquid-state density functional theory utilizing coarse-grained models are conducted to demonstrate that the protein–PEG effective attraction is responsible for the suppression and promotion of LLPS upon the addition of low- and high-weight PEG, respectively. In contrast, if the interactions between the protein and the PEG are solely due to the excluded volume effect, PEG of any molecular weight destabilizes the solution. These results suggest the necessity to reconsider the conventional understanding of the effects of polymer addition, which have been historically attributed to solely the depletion force.
Numerical study of the effect of stenosis on the hemodynamics of a popliteal artery
Authors: Shi Liuliu , Xiang Xinru , Liu Jinlong , Zhu Wei
Published: February 2025

The investigation of flow characteristics within the popliteal artery is fundamental to understanding the progression of lower limb arterial disease, given its high susceptibility to atherosclerosis and its frequent manifestation of stenosis. Research on the hemodynamics associated with popliteal artery stenosis remains limited, particularly in cardiovascular diseases. This study comprehensively examines how Newtonian and non-Newtonian fluid models influence the hemodynamic simulations of popliteal artery stenosis. Key hemodynamic parameters, such as velocity, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT), were systematically examined through numerical simulations to assess their influence and variability in arteries exhibiting different degrees of stenosis compared to healthy arteries. The findings indicate that both models’ velocity and wall shear stress (WSS) distributions are largely comparable during the systolic phase (0.04–0.07 s), characterized by elevated velocities. However, during the countercurrent diastolic phase (0.21–0.40 s), the viscosity of the non-Newtonian fluid model experiences an increase, leading to reduced velocity distributions relative to the Newtonian fluid model. In particular, a 12% disparity in velocities is observed between the two models, indicating that the non-Newtonian model is better suited for comprehensive hemodynamic analysis in simulations involving stenotic popliteal arteries. Furthermore, a distinct flow separation occurs at the stenosis site, with blood flow velocity and WSS exhibiting significant increases as the stenosis severity escalates. For instances where hemodynamic parameters demonstrate minimal variations at stenosis levels below 60%, OSI and RRT are elevated. In contrast, TAWSS remains low, potentially fostering plaque formation. In contrast, when hemodynamic parameters undergo substantial changes at stenosis levels exceeding 60%, TAWSS rises, which may facilitate plaque rupture. This simulation provides a comprehensive analysis of hemodynamic parameter variations across different degrees of stenosis, offering clinicians a valuable instrument for enhancing their understanding of the pathogenic mechanisms associated with popliteal artery atherosclerosis and stenosis.
Reconstruction of the solid–liquid two-phase flow field in the pipeline based on limited pipeline wall information
Authors: Xiao Shengpeng , Wan Chuyi , Zhu Hongbo , Zhou Dai , Bao Yan , Huang Shuai , Zhang Mengmeng , Han Zhaolong
Published: February 2025

Pipeline hydraulic transportation is the primary method for transporting deep-sea mineral resources and fossil fuels. Pipeline blockage often causes excessive pressure in the pipeline, leading to pipeline breakage or even cargo leakage, which severely impacts transportation safety and can easily trigger secondary disasters. Therefore, clarifying the global flow field within pipelines, such as particle distribution, is crucial for monitoring and controlling pipeline systems. This study uses a limited number of easily measurable pipeline wall sensor pressure values as inputs of deep learning models for flow field reconstruction, with the global flow field of solid–liquid two-phase flow in the three-dimensional pipeline as the output. Three model frameworks from existing studies are summarized, and their reconstruction effects are compared. Based on this, a new framework is proposed. It expands the low-dimensional sensor pressure values to the same size as the global flow field using a pseudo-decoder and then processes them through an autoencoder. The results indicate that the new framework achieves further accuracy improvements compared to the previous three frameworks, with R2 and mean squared error reaching 0.933 and 5.13 ×10−4, respectively. Additionally, the effects of the skip connection configuration of the model, dataset size, and model learning rate, as well as the number and arrangement of pressure sensors on reconstruction accuracy, are investigated. Finally, the transferability of the model is demonstrated by reconstructing the pressure and fluid velocity fields of the pipeline two-phase flow.
Generalized bond polarizability model for more accurate atomistic modeling of Raman spectra
Authors: Paul Atanu , Samala Nagaprasad Reddy , Grinberg Ilya
Published: February 2025

Raman spectroscopy is an important tool for studying molecules, liquids and solids. While Raman spectra can be obtained theoretically from molecular dynamics (MD) simulations, this requires the calculation of electronic polarizability along the simulation trajectory. First-principles calculations of electronic polarizability are computationally expensive, motivating the development of atomistic models for the evaluation of the changes in the electronic polarizability with the changes in the atomic coordinates of the system. The bond polarizability model (BPM) is one of the oldest and simplest such atomistic models but cannot reproduce the effects of angular vibrations, leading to inaccurate modeling of Raman spectra. Here, we demonstrate that the generalization of BPM through the inclusion of terms for atom pairs that are traditionally considered to be not involved in bonding dramatically improves the accuracy of polarizability modeling and Raman spectra calculations. The generalized BPM (GBPM) reproduces the ab initio polarizability and Raman spectra for a range of tested molecules (SO2, H2S, H2O, NH3, CH4, CH3OH, and CH3CH2OH) with high accuracy and also shows significantly improved agreement with ab initio results for the more complex ferroelectric BaTiO3 systems. For liquid water, the anisotropic Raman spectrum derived from atomistic MD simulations using the GBPM evaluation of polarizability shows significantly improved agreement with the experimental spectrum compared to the spectrum derived using the BPM. Thus, the GBPM can be used for the modeling of Raman spectra using large-scale molecular dynamics and provides a good basis for the further development of atomistic polarizability models.