bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropic fluctuation conductivity of thin superconducting films of transition metals
Authors: Cherkasova V. G. , Dmitrenko I. M. , Fogel’ N. Ya.
Published: December 2024

The angular dependence of the width of superconducting transitions in a magnetic field in thin vanadium and niobium films in the region of strong fluctuations is studied. Two special orientations of the magneic field relative to the surface of the film were discovered: the angle θ0 at which the width of the transition is maximum and the angle θt separating the region of angles in one of which the fluctuation behavior is determined solely by the component of the external magnetic field perpendicular to the film, while in the other the magnitude of the parallel component is also significant. The dependence of θ0 and θt on the temperature is studied. The experimental data are in qualitative agreement with the theory describing the orientational dependence of the smearing of the transitions for two-dimensional superconductors in the region of weak fluctuations. The three-dimensional phase diagaram in the space H, T, and θ, determining the critical region, is constructed.
Nonlinear size cyclotron resonance in bismuth
Authors: Kopasov A. P.
Published: December 2024

Second-harmonic generation on reflection of an electromagnetic wave from a thin conducting plate whose thickness is much greater than the depth of the skin layer but much smaller than the electron mean free path length, in a magnetic field parallel to the surface of the plate is studied. The analysis is performed taking into correct account the scattering of electrons by the boundaries, which was assumed to be close to diffuse. Numerical calculations of the amplitude and phase of the reflected second harmonic as a function of the magnetic field were carried out in the case of bismuth near the nonlinear resonance, when the doubled frequency of the electromagnetic wave is a multiple of the cyclotron frequency of the electrons, whose orbital diameter equals the thickness of the plate. The dispersion law for electrons in bismuth was described by the McClure–Choi model.
Effect of the exchange interaction between O2 impurity molecules on the thermodynamic properties of cryocrystals
Authors: Ostrovskiĭ V. S. , Sumarokov V. V. , Freĭman Yu. A.
Published: December 2024

The spectrum of a paired O2 molecule cluster is calculated for an arbitrary relative orientation of the molecular axes and an arbitrary ratio between the exchange-interaction constant and the anisotropy factor. The resulting spectra are used to calculate the contributions of paired O2 molecule clusters to the thermodynamic characteristics (heat capacity, Grüneisen constant, thermal expansion) of solid solutions of solidified gases containing O2 as an impurity. The solutions of oxygen in cryocrystals are shown to be of interest not only from the standpoint of their anomalous thermodynamic properties but also because they can provide information about the dependence of the exchange interaction of oxygen molecules on both the intermolecular separation and the intermolecular orientations. Thermal expansion is the thermodynamic characteristic that is most sensitive to a change in the orientational structure of the clusters.
Mechanisms of nonlinear conductivity and electrodynamics of quasi-one-dimensional conductors in the Peierls insulator state (review)
Authors: Krive I. V. , Rozhavskiĭ A. S. , Kulik I. O.
Published: December 2024

The nonlinear electromagnetic properties of quasi-one-dimensional conducting compounds in the Peierls phase are analyzed on the basis of the functional formalism developed in recent years. Such conductors can be divided into two major classes: conducting polymers with Peierls period doubling and quasi-one-dimensional metals with planar segments of the Fermi surface, which are characterized by the appearance of a charge density wave (CDW). A strong electric field has been shown to cause polarization of the Peierls state and tunneling generation of specific excitations, soliton–antisoliton pairs. We examine the contribution that collective excitations—solitons, large-radius polarons, and bipolarons—make to the conductivity. The distinctive features of optical and infrared absorption, parametric resonance, and anomalous magnetic properties are considered. Threshold effects in the conductivity of the Peierls state as a result of metallization and soliton dynamics are also discussed.
Magnetooptical determination of the parameters of exchange interactions in antiferromagnetic iron carbonate
Authors: Kharchenko N. F. , Belyi L. I. , Gnatchenko S. L. , Eremenko V. V.
Published: December 2024

The dispersion and temperature dependence of the Faraday effect in siderite—iron carbonate of natural origin—was studied. It is shown that the Faraday rotation in siderite in the visible region of the spectrum is of an electric dipole nature and is of the paramagnetic type. It is concluded from an analysis of the temperature dependence of the inverse specific rotation (Φ/ ±H)−1 that the concept of the paramagnetic Curie temperature for iron carbonate becomes meaningless in the temperature range from TN = 38 K up to 300 K. The temperature dependence of the magnetic susceptibility χ(T) is reconstructed from the experimental temperature dependence of the specific Faraday rotation. Analysis of the high- and low-temperature parts of this dependence in the molecular-field approximation shows that the exchange interaction between ions in the same sublattice (second magnetic neighbors) is antiferromagnetic. The parameters characterizing the intersublattice 2J1q1/k = −(11.0±1.5) K and intrasublattice 2J2q2/k = −(2.5±1.5) K exchange interactions are determined.
Low-lying impurity states in quasi-one-dimensional magnetic systems
Authors: Ezerskaya E. V. , Tsukernik V. M.
Published: December 2024

The effect of impurities on the spectrum of one-magnon excitations of two quasi-one-dimensional spin systems—a double XY chain with an impurity atom and an analogous chain with an impurity link, in which two identical impurity atoms occupy neighboring nodes on different XY chains—is studied. The conditions for the existence of impurity levels and their number are determined for the system with one impurity, and for the system with an impurity link the explicit expressions for the energy and wave functions of localized states are also determined.
Superconductivity of indium single-crystals with twinned interlayers in fields greater than H
c2
Authors: Dolgin A. M. , Bengus V. Z.
Published: December 2024

Superconductivity has been found in indium single-crystals in fields Hc2 < H < 1.65 Hc2, arising as a result of twinning on low-temperature deformation. The flow of superconducting currents in fields greater than Hc2 is provided by a three-dimensional network of twin boundaries in two intersecting crystallographic systems. The appreciable influence of relaxation processes, which take place on heating the crystal, on the critical fields and superconducting currents associated with the twin boundaries has been established.
Amplitude characteristics of the Shubnikov–de Haas effect for intercalation compounds in second-stage acceptor-type graphite
Authors: Brandt N. B. , Davydov V. N. , Kul’bachinskii V. A. , Nikitina O. M.
Published: December 2024

The angular dependence of the amplitude of the Shubnikov–de Haas oscillations is investigated for intercalation compounds in second-stage graphite C16ICl and C10CuCl2. A model is formulated to account for the decrease in the amplitude of the oscillations when the angle between the direction of the magnetic field and the c axis of the sample is increased.
Upgrades to x-ray microcalorimeter fusion diagnostic to improve calibration, spectral bandwidth selection, and count rate adjustment
Authors: Kubala S. Z. , Beatty C. B. , Beiersdorfer P. , Brown G. V. , Den Hartog D. J. , Eckart M. E. , Flores-Alimboyoguen H. J. , Hell N. , Kelley R. L. , Kilbourne C. A. , Leutenegger M. A. , Magee E. W. , Porter F. S. , Witthoeft M. C.
Published: December 2024

This paper presents progress made toward the overarching goal to adapt single-photon-counting microcalorimeters to magnetic fusion energy research and demonstrate the value of such measurements for fusion. Microcalorimeter spectrometers combine the best characteristics of x-ray instrumentation currently available on fusion devices: high spectral resolution similar to an x-ray crystal spectrometer and broad spectral coverage sufficient to measure impurity species from Be to W. As a proof-of-principle experiment, a NASA-built x-ray microcalorimeter spectrometer has been installed on the Madison Symmetric Torus (MST) at the Wisconsin Plasma Physics Laboratory. For fusion applications, microcalorimeters will provide multi-species impurity ion data and will also contribute to the measurements of impurity ion temperature and flow velocity, Zeff, and electron density. Here, improvements to the microcalorimeter setup at MST and spectra acquired with the upgraded system are presented. Four motor-controlled wheels, loaded with x-ray fluorescence targets for continuous gain-drift tracking and broad energy-scale calibration, filters, and apertures, were added to the diagnostic’s beamline. A stronger 55Fe source was added as an additional x-ray source for calibration. The 55Fe source, targets, filters, and apertures can be moved into and out of the optical path. Several configurations are now accessible for shot-to-shot adjustments to the count rate and waveband, enabling the measurement of x-ray photons emitted by a variety of impurity ions in the majority deuterium plasma, including aluminum, carbon, and argon.
Code-to-code comparison between FLASH and HYDRA in gas-puff Z-pinch modeling
Authors: Michta D. , Tranchant V. , Narkis J. , Hansen E. C. , Adams M. B. P. , Moczulski K. , Reyes A. , Conti F. , Beg F. N. , Tzeferacos P.
Published: December 2024

The numerical modeling of gas-puff Z pinches involves the nonlinear coupling of a broad range of complex, multi-physics phenomena that makes such simulations challenging. The challenge is further compounded by nonlinear instabilities that can impact the dynamics of imploding gas-puff Z pinches, such as the magneto Rayleigh–Taylor instability (MRTI). If the growth rate and amplitude of the latter is comparable to the relevant timescales and properties of the imploding plasma, the MRTI can dramatically alter implosion dynamics, dictate pinch stability, and govern the plasma properties achievable in pulsed-power-driven laboratory experiments. National Laboratories and academic teams have developed numerical tools that can accurately model Z-pinch configurations and provide reliable design capabilities that can guide experimental choices and assist in interpreting experimental results. Most such tools, however, are not broadly available. Here, we present newly developed Z-pinch simulation capabilities of the publicly available FLASH code, applied in the study of MRTI growth and dynamical effects in gas-puff implosions. To verify the new implementations, we perform a comparison of FLASH gas-puff implosion simulations with previously published calculations with the HYDRA code from Lawrence Livermore National Laboratory, which have been validated with experimental data from the CESZAR pulsed-power driver at the University of California, San Diego. The experiments involved double- and triple-nozzle configurations, in an experimental attempt to stabilize the pinch to the MRTI. The code-to-code comparison shows similar results between the FLASH and HYDRA simulations, supporting the use of FLASH in the modeling of future gas-puff Z-pinch experiments at CESZAR.
The linear electromagnetic gyrokinetic global simulation by using the numerical Lie-transform code
Authors: Zhang Guodong , You Jinxiang , Wang Zihao , Wu Tiannan , Qiu Yuefeng , Wang Lu , Wang Shaojie
Published: December 2024

Electromagnetic gyrokinetic simulation plays an important role in the research of anomalous transport driven by micro-turbulence in tokamak fusion plasmas. The development of electromagnetic gyrokinetic codes usually faces challenges including physical model, numerical instabilities as well as corresponding algorithms and accuracy; one of the typical challenges is the well-known cancellation problem. In this work, the gyrokinetic code NLT [Ye et al., J. Comput. Phys. 316, 180 (2016)] is updated to the electromagnetic version. The scheme of mitigating the cancellation problem in GYRO [Candy and Waltz, J. Comput. Phys. 186, 545 (2003)] is adopted. The simulation results including the real frequency, linear growth rate, and mode structures of the ion temperature gradient mode and the trapped electron mode as well as the kinetic ballooning mode from NLT are consistent with those from previous Eulerian and particle in cell codes. Moreover, it is found that the cancellation problem does not exist, at least for the drift waves, in the NLT simulation.
Influence of wake field inhomogeneity on the vibrational spectra of two dust particles in a plasma with an ion flow
Authors: Sametov E. A. , Kolotinskii D. A. , Lisin E. A. , Timofeev A. V.
Published: December 2024

A charged colloidal (dust) particle immersed in a plasma with an ion flow creates a disturbed region behind it, known as a wake. The paper considers a system of two charged and strongly coupled microparticles aligned along the ion flow in a weakly ionized plasma (e.g., in the plasma sheath of a ground-based RF discharge) and confined vertically by an external electric field. Using the OpenDust code, a fully self-consistent numerical simulation of the dynamics of dust particles and the ionic component is carried out. It is demonstrated that the inhomogeneity of the wake field from the upstream particle can significantly change the spectrum of vertical (longitudinal) vibrations of both particles in the system and has a negligible effect on their horizontal (transverse) vibrations. In particular, a relationship exists between horizontal and vertical particle oscillations, manifested as an additional mode of vertical vibrations of particles corresponding to the doubled frequency of their relative horizontal vibrations. In accordance with the model of nonreciprocally coupled stochastically driven oscillators, analytical expressions are derived for the vibrational spectra of particles taking into account the spatial variations in particle charges caused by inhomogeneities in the surrounding plasma. The proposed theory improves the experimental method of spectral response to stochastic processes, enabling the measurement of effective forces, particle friction coefficients, and temperatures of their heat sources, as well as the horizontal charge gradient of the lower particle oscillating in the wake field of the upper one.
Preserving Coulomb blockade in transport spectroscopy of quantum dots
by dynamical tunnel barrier compensation
Authors: Jangir V. , Shah D. , Samanta S. , Rastogi S. , Beere H. E. , Ritchie D. A. , Das Gupta K. , Mahapatra S.
Published: December 2024

Surface-gated quantum dots (QDs) in semiconductor heterostructures represent a highly attractive platform for quantum computation and simulation. However, in this implementation, the barriers through which the QD is tunnel-coupled to source and drain reservoirs (or neighboring QDs) are usually non-rigid and capacitively influenced by the plunger-gate voltage (VP). In transport spectroscopy measurements, this leads to suppression of current and lifting of the Coulomb blockade for increasing negative and positive values of VP, respectively. Consequently, the charge-occupancy of the QD can be tuned over a rather small range of VP. By dynamically tuning the tunnel barriers to compensate for the capacitive effect of VP, here we demonstrate a protocol that allows Coulomb blockade to be preserved over a remarkably large span of charge-occupancies, as demonstrated by clean Coulomb diamonds and well-resolved excited state features. The protocol will be highly beneficial for automated tuning and identification of the gate voltage space for optimal operation of QDs in large arrays required for a scalable spin quantum computing architecture.
Influences of radial migration flow on the compressor stage losses under low Reynolds number conditions
Authors: Zhang Shuqiu , Lu Hanan , Li Qiushi
Published: December 2024

Radial migration flow structures on the blade suction surface in the rotor are commonly observed in transonic axial-flow fan/compressors. At sea level conditions, its intensity is relatively weak and causes very slight aerodynamic losses. However, under high-altitude low Reynolds number conditions, the radial migration flow will be significantly intensified. It will have strong interactions with other flow structures (such as shock wave, tip leakage flow, and wake) in the blade passage and lead to innegligible efficiency deficit in the entire compressor stage. To enhance the compressor performances at low Reynolds number conditions, it is crucial to achieve fundamental understandings of the origination, development, and downstream effects of radial migration flow. This paper conducted a detailed numerical investigation on the influences of radial migration flow near the rotor blade suction surface on the additional loss in a transonic compressor stage. The computational results confirm that under high-altitude conditions, radial migration flow is originated at the rotor blade hub corner and develops from the local separated flow and vortex. Its trajectory is largely determined by the interaction between the shock wave and the boundary layer flow, eventually mixing with the tip leakage flow and causing an accumulation of low-momentum flow near the casing. The migration of radial flow along the spanwise fraction interacts with the rotor blade wake and results in a larger total pressure and velocity deficit at the downstream stator inlet, deteriorating the aerodynamic loss in the stator blade. Meanwhile, the radial migration flow can be also triggered by the corner separation on the stator suction surface near the trailing edge, which exacerbates the local loss in the blade passage. Based on the features of radial migration flow, blade bend re-designs mainly near the hub and shroud ends have been applied to the rotor. It shows that the re-designed rotor has achieved an alleviated radial migration flow and a reduced wake zone at low Reynolds number conditions. Moreover, the re-designed compressor shows a notable higher adiabatic efficiency than the baseline one over the entire operating range, while the total pressure ratio and stable operating range are not sacrificed.
Nucleation mechanism of multiple-order parameter ferroelectric domain wall motion in hafnia
Authors: Zhou Songsong , Rappe Andrew M.
Published: December 2024

Ferroelectric hafnia exhibits promising robust polarization and silicon compatibility for ferroelectric devices. Unfortunately, it suffers from difficult polarization switching. Methods to enable easier polarization switching are needed, and the underlying reason for this switching difficulty is not understood. Here, we investigated the 180
°
domain walls of hafnia and their motion through nucleation. We found that the domains of multiple-order parameter hafnia possess complicated three-dimensional dipole patterns and lead to domain walls of different symmetry. The most common domain wall type is a complex domain wall involving reversal of both polarization and tetragonality order parameters. This domain wall symmetry ensures a good matching of the dipoles perpendicular to the domain wall, which leads to low domain wall energy. However, this ensures a sharp, high-energy, charged domain wall on the edges of nuclei that results in difficult nucleation. Thus, this domain wall is too stable to move, which explains the switching difficulty of hafnia. By contrast, another simple domain wall, involving only polarization reversal, has a poor matching of dipoles perpendicular to the domain wall. This leads to higher domain wall energy and ensures a diffusive and low-energy charged domain wall that enables easier nucleation. This simple domain wall is thus not too stable and easier to move. Our theory advances domain wall nucleation theory from the field of conventional single-order parameter to multiple-order parameters. We propose controlling the populations of different domain wall types in hafnia as a way to enable fast polarization switching and lower coercive fields.
Tamsulosin ameliorates bone loss by inhibiting the release of Cl
−
through wedging into an allosteric site of TMEM16A
Authors: Li Shiliang , Sun Weijia , Li Shuang , Zhu Lili , Guo Shuai , He Jiaqi , Li Yuheng , Tian Chaoquan , Zhao Zhenjiang , Yu Tao , Li Jianwei , Zhang Yiqing , Hai Youlong , Wang Jiawen , Zheng Yongjun , Wang Rui , Hu Xiaoyong , Ling Shukuan , Li Honglin , Li Yingxian
Published: December 2024

TMEM16A, a key calcium-activated chloride channel, is crucial for many physiological and pathological processes such as cancer, hypertension, and osteoporosis, etc. However, the regulatory mechanism of TMEM16A is poorly understood, limiting the discovery of effective modulators. Here, we unveil an allosteric gating mechanism by presenting a high-resolution cryo-EM structure of TMEM16A in complex with a channel inhibitor that we identified, Tamsulosin, which is resolved at 2.93 Å. Tamsulosin wedges itself into a pocket within the extracellular domain of TMEM16A, surrounded by α1-α2, α5-α6, and α9-α10 loops. This binding stabilizes a transient preopen conformation of TMEM16A, which is activated by Ca
2+
ions while still preserving a closed pore to prevent Cl
−
permeation. Validation of this binding site through computational, electrophysiological, and functional experiments, along with site-directed mutagenesis, confirmed the pivotal roles of the pocket-lining residues R605 and E624 on α5-α6 loop in modulating Tamsulosin binding and pore activity. Tamsulosin induces significant positional shifts in extracellular loops, particularly the α5-α6 loop, which moves toward the extracellular exit of the pore, leading to noticeable structural rearrangements in pore-lining helices. The hinges induced by P595 in α5 and G711 in α7 introduce flexibility to the transmembrane helices, orienting Y593 to collaborate with I641 in effectively gating the preopening pore. Notably, Tamsulosin demonstrates significant antiosteoporotic effects by inhibiting TMEM16A, suggesting potential for its repurposing in new therapeutic indications. Our study not only enhances our understanding of the gating mechanism of TMEM16A inhibition but also facilitates structure-based drug design targeting TMEM16A.
A mechanosensitive circuit of FAK, ROCK, and ERK controls biomineral growth and morphology in the sea urchin embryo
Authors: Layous Majed , Gildor Tsvia , Nehrer Tovah , Qassem Areen , Wolfenson Haguy , Ben-Tabou de-Leon Smadar
Published: December 2024

Biomineralization is the utilization of different minerals by a vast array of organisms to form hard tissues and shape them in various forms. Within this diversity, a common feature of all mineralized tissues is their high stiffness, implying that mechanosensing could be commonly used in biomineralization. Yet, the role of mechanosensing in biomineralization is far from clear. Here, we use the sea urchin larval skeletogenesis to investigate the role of substrate stiffness and focal adhesion kinase (FAK) in biomineralization. We demonstrate that substrate stiffness alters spicule morphology and growth, indicating a mechanosensitive response during skeletogenesis. We show that active FAK, F-actin, and vinculin are enriched around the spicules, indicating the formation of focal adhesion complexes and suggesting that the cells sense the mechanical properties of the biomineral. Furthermore, we find that FAK activity is regulated by Rho-associated protein kinase (ROCK) and is crucial for skeletal growth and normal branching. FAK and ROCK activate extracellular signal-regulated kinase (ERK), which regulates skeletogenic gene expression at the tips of the spicules. Thus, the FAK-ROCK-ERK circuit seems to provide essential mechanical feedback on spicule elongation to the skeletogenic gene regulatory network, enabling skeletal growth. Remarkably, the same factors govern mammalian osteoblast differentiation in vitro and pathological calcification in vivo. Thus, this study highlights a common mechanotransduction pathway in biomineralization that was probably independently co-opted across different organisms to shape mineralized structures in metazoans.
Molecular mechanism governing the plasticity of use-dependent spike broadening in dorsal root ganglion neurons
Authors: Alexander Tyler D. , Tymanskyj Stephen , Kennedy Kyle J. , Kaczmarek Leonard K. , Covarrubias Manuel
Published: December 2024

Use-dependent spike broadening (UDSB) results from inactivation of the voltage-gated K
+
(Kv) channels that regulate the repolarization of the action potential. However, the specific signaling and molecular processes that modulate UDSB have remained elusive. Here, we applied an adeno-associated viral vector approach and dynamic clamping to conclusively demonstrate how multisite phosphorylation of the N-terminal inactivation domain (NTID) of the Kv3.4 channel modulates UDSB in rat dorsal root ganglion (DRG) neurons. The Kv3.4 phosphonull variant promotes slow recovery from inactivation, cumulative inactivation, and UDSB. In contrast, the Kv3.4 phosphomimic variant promotes fast recovery from inactivation and robust resistance to cumulative inactivation and UDSB. Furthermore, knocking down Kv3.4 maximizes AP width and eliminates UDSB modulation. Together with the evidence from previous work, the results concretely suggest how dynamic UDSB modulation governed by multisite phosphorylation of the NTID of Kv3.4 in DRG neurons may play a significant role in mechanosensory transduction and pain modulation.
A conifer metabolite corrects episodic ataxia type 1 by voltage sensor–mediated ligand activation of Kv1.1
Authors: Manville Rían W. , Foglia Lorenzo , Yoshimura Ryan F. , Hogenkamp Derk J. , Nguyen Amy , Yu Alvin , Abbott Geoffrey W.
Published: December 2024

Loss-of-function sequence variants in
KCNA1
, which encodes the voltage-gated potassium channel Kv1.1, cause Episodic Ataxia Type 1 (EA1) and epilepsy. Due to a paucity of drugs that directly rescue mutant Kv1.1 channel function, current therapeutic strategies for
KCNA1
-linked disorders involve indirect modulation of neuronal excitability. Native Americans have traditionally used conifer extracts to treat paralysis, weakness, and pain, all of which may involve altered electrical activity and/or Kv1.1 dysfunction specifically. Here, screening conifer extracts, we found that
Chamaecyparis pisifera
increases wild-type (WT) Kv1.1 activity, as does its prominent metabolite, the abietane diterpenoid pisiferic acid. Uniquely, pisiferic acid also restored function in 12/12 EA1-linked mutant Kv1.1 channels tested in vitro. Crucially, pisiferic acid (1 mg/kg) restored WT function in Kv1.1
E283K/+
mice, a model of human EA1. Experimentally validated all-atom molecular dynamics simulations in a neuron-like membrane revealed that the Kv1.1 voltage-sensing domain (VSD) also acts as a ligand-binding domain akin to those of classic ligand-gated channels; binding of pisiferic acid induces a conformational shift in the VSD that ligand-dependently opens the pore. Conifer metabolite pisiferic acid is a promising and versatile therapeutic lead for EA1 and other Kv1.1-linked disorders.
Concomitant formation of protocells and prebiotic compounds under a plausible early Earth atmosphere
Authors: Jenewein Christian , Maíz-Sicilia Aurora , Rull Fernando , González-Souto Lorena , García-Ruiz Juan Manuel
Published: December 2024

Revealing the origin of life and unambiguously detecting fossil remains of the earliest organisms are closely related aspects of the same scientific research. The synthesis of prebiotic molecular building blocks of life and the first compartmentalization into protocells have been considered two events apart in time, space, or both. We conducted lightning experiments in borosilicate reactors filled with a mixture of gases mimicking plausible geochemical conditions of early Earth. In addition to the variety of prebiotic organic molecules synthesized in these experiments, we investigated the micrometer-thick silica-induced organic film that covers the walls of the reactors and floats at the water–gas interface. We found that the film is formed by aggregation of HCN-polymer nanoclusters whenever water is present, either in the liquid or vapor phase. The organic film morphs into micrometer-scale biomorphic vesicular structures hanging from the organic film into the water. We also show that these structures are hollow and may act as microreactors facilitating chemical pathways toward increasing complexity. We propose that these organic biomorphs form through a bubble-driven mechanism and interfacial precipitation of HCN-polymers. The concomitant synthesis of biomorphic poly-HCN protocells and prebiotic molecules under plausible geochemical conditions of early Earth-like planets and moons and opens a different geochemical scenario for the emergence of life. Our results suggest that the coexistence of molecular building blocks of life and submicron biomorphic structures in the oldest rocks on Earth or any other celestial body does not necessarily mean evidence of life.
Deciphering the role of the MALT1–RC3H1 axis in regulating GPX4 protein stability
Authors: Wang Jun , Liao Long , Miao Beiping , Yang Bo , Li Botai , Ma Xuhui , Fitz Annika , Wu Shanshan , He Jia , Zhang Qianqian , Ji Shuyi , Jin Guangzhi , Zhang Jianming , Cao Ying , Wang Hui , Qin Wenxin , Sun Chong , Bernards René , Wang Cun
Published: December 2024

Ferroptosis, a unique form of iron-dependent cell death triggered by lipid peroxidation accumulation, holds great promise for cancer therapy. Despite the crucial role of GPX4 in regulating ferroptosis, our understanding of GPX4 protein regulation remains limited. Through FACS-based genome-wide CRISPR screening, we identified MALT1 as a regulator of GPX4 protein. Inhibition of MALT1 expression enhances GPX4 ubiquitination-mediated degradation by up-regulating the E3 ubiquitin ligase RC3H1. Using both rescue assays and functional genetic screening, we demonstrate that pharmacologically targeting MALT1 triggers ferroptosis in liver cancer cells. Moreover, we show that targeting MALT1 synergizes with sorafenib or regorafenib to induce ferroptosis across multiple cancer types. These findings elucidate the modulatory effects of the MALT1–RC3H1 axis on GPX4 stability, revealing a molecular mechanism that could be exploited to induce ferroptosis for cancer therapy.
Structural and functional dynamics of human cone cGMP-phosphodiesterase important for photopic vision
Authors: Singh Sneha , Srivastava Dhiraj , Boyd Kimberly , Artemyev Nikolai O.
Published: December 2024

Cone cGMP-phosphodiesterase (PDE6) is the key effector enzyme for daylight vision, and its properties are critical for shaping distinct physiology of cone photoreceptors. We determined the structures of human cone PDE6C in various liganded states by single-particle cryo-EM that reveal essential functional dynamics and adaptations of the enzyme. Our analysis exposed the dynamic nature of PDE6C association with its regulatory γ-subunit (Pγ) which allows openings of the catalytic pocket in the absence of phototransduction signaling, thereby controlling photoreceptor noise and sensitivity. We demonstrate evolutionarily recent adaptations of PDE6C stemming from residue substitutions in the Pγ subunit and the noncatalytic cGMP binding site and influencing the Pγ dynamics in holoPDE6C. Thus, our structural analysis sheds light on the previously unrecognized molecular evolution of the effector enzyme in cones that advances adaptation for photopic vision.
XSL-FO
Authors: Graham Tony
Published: December 2024

XSL-FO is more declarative than you know. When the processing model has no feedback between the XSLT stage and the final output and no
conditionals in the expression language, everything has to be declarative. You declare up front everything from the page masters to use for
left, right, first, last, and only pages (if the document makes any of those) to the index keys and their classes that are collected and
potentially merged into page number ranges to initial letters that are sized align at the top with small capital letters on the first line
and at the bottom with the baseline of a line further down the block. This paper covers all of those, and more, to show just how declarative
XSL-FO can be.
The phospholipid kinase PIKFYVE is essential for Th17 differentiation
Authors: Prado Douglas S. , Cattley Richard T. , Sonego Andreza B. , Sutariya Parth , Wu Shuxian , Lee Mijoon , Boggess William C. , Shlomchik Mark J. , Hawse William F.
Published: December 2024

T helper 17 (Th17) cells are effector cells that mediate inflammatory responses to bacterial and fungal pathogens. While the cytokine signaling inputs required to generate Th17s are established, less is known about intracellular pathways that drive Th17 differentiation. Our previously published phosphoproteomic screen identifies that PIKFYVE, a lipid kinase that generates the phosphatidylinositol PtdIns(3,5)P2, is activated during Th17 differentiation. Herein, we discovered that PIKFYVE regulates kinase and transcription factor networks to promote Th17 differentiation. As a specific example, PtdIns(3,5)P2 directly stimulates mTORC1 kinase activity to promote cell division and differentiation pathways. Furthermore, PIKFYVE promotes STAT3 phosphorylation, which is required for Th17 differentiation. Chemical inhibition or CD4-specific deletion of PIKFYVE reduces Th17 differentiation and autoimmune pathology in the experimental autoimmune encephalomyelitis murine model of multiple sclerosis. Our findings identify molecular mechanisms by which PIKFYVE promotes Th17 differentiation and suggest that PIKFYVE is a potential therapeutic target in Th17-driven autoimmune diseases.
The calcium-binding protein S100A1 binds to titin’s N2A insertion sequence in a pH-dependent manner
Authors: Apel Sabrina I. , Schaffter Emily , Melisi Nicholas , Gage Matthew J.
Published: December 2024

Titin is the third contractile filament in the sarcomere, and it plays a critical role in sarcomere integrity and both passive and active tension. Unlike the thick and thin filaments, which are polymers of myosin and actin, respectively, titin is a single protein that spans from Z-disk to M-line. The N2A region within titin has been identified as a signaling hub for the muscle and is shown to be involved in multiple interactions. The insertion sequence (UN2A) within the N2A region was predicted as a potential binding site for the Ca2+-binding protein, S100A1. We demonstrate using a combination of size exclusion chromatography, surface plasmon resonance, and fluorescence resonance energy transfer that S100A1 can bind to the UN2A region. We further demonstrate that this interaction occurs under conditions where calcium is bound to S100A1, suggesting that the conformational shift in S100A1 when calcium binds is important. We also observed a conformational change in UN2A induced by shifts in pH, suggesting that conformational flexibility in UN2A plays a critical role in the interaction with S100A1. These results lead us to propose that the interaction of S100A1 and UN2A might act as a sensor to regulate titin’s function in response to physiological changes in the muscle.
The enhancement of ferromagnetism in 2D tetragonal CoSe by electric fields and Janus engineering
Authors: Peng Yiran , Ge Yanfeng , liu Yong , Markowska Katarzyna , Wan Wenhui
Published: December 2024

Two-dimensional (2D) cobalt-based anti-MXene materials have been synthesized, but their poor ferromagnetism limits their spintronic applications. In this study, we employed first-principles calculations to investigate the various methods to modulate the magnetic properties of monolayer CoSe. The competition between the Co–Co direct exchange interaction, Co–Se–Co super-exchange interaction, and Ruderman–Kittel–Kasuya–Yosida exchange interaction lead to the weak ferromagnetism of monolayer CoSe. The strain slightly enhances the Curie temperatures (

T

c

)

of monolayer CoSe, but the substrate is ineffective. In comparison, a vertical electric field Ez
of 0.5 V Å−1 can enhance

T

c

from 8 K to 161 K. This enhancement stems from reinforcing Co–Se–Co superexchange by electric fields. Among the Janus structures based on the CoSe, monolayer Co2SeS can exhibit a

T

c

of 40 K, due to the interplay between strain and built-in electric field. Our results suggested that polar substrates or Janus engineering can promote the ferromagnetism of 2D CoSe for spintronic applications.
High-performance, self-powered ZnO NWs-ZnSe heterojunction photodetectors for superior visible and near-infrared detection
Authors: Hassan Zamir-ul- , Batool Syeda Farzana , Kazmi Jamal , Raza Syed Raza Ali , Shah Jafar Hussain , Jalil Abdul , Kaplan Hüseyin Kaan , Akay Sertan Kemal , Khan Raja Azhar Saeed , Rafique Mohsin
Published: December 2024

We present the development of a type-II heterojunction photodetector (PD) comprising Ag/ZnO nanowires (NWs)/ZnSe/In, fabricated on a commercially available Si substrate. ZnO NWs were hydrothermally synthesized on thermally evaporated ZnSe thin films, with scanning electron microscopy (SEM) analysis revealing uniform, vertically aligned ZnO NWs on the ZnSe layer. Cross-sectional SEM imaging determined the thickness of the In/ZnSe thin film to be approximately 460 nm, with ZnO NWs exhibiting an average diameter of ∼161 nm. Structural analysis of the ZnSe thin film, annealed at 370 °C in an ambient environment, identified a prominent ZnSe peak at 27.48° alongside peaks at 30.98° and 33.21° corresponding to In2O3 and ZnSeO3, respectively. The ZnO NWs, under similar annealing conditions, displayed a strong (002) peak, confirming vertical growth. Hall effect measurements revealed a transition from p-type carriers in as-deposited ZnSe thin films to n-type in the annealed ZnSe and ZnO NWs, attributed to the formation of In2O3 as evidenced by XRD. The PD exhibited the highest photoresponse under IR illumination (950 nm), surpassing responses to green (515 nm) and blue (456 nm) LEDs, with a short-circuit current (I
sc) of −26 μA and an open-circuit voltage (V
oc) of +80 mV, characteristic of a self-powered device. In contrast, minimal photoresponse was observed in a Schottky-type Ag/ZnSe/In junction on the Si substrate. The photoresponse mechanism was elucidated using an energy band diagram, while density functional theory simulations using Vienna ab initio simulation package provided a strong correlation with the experimental data, validating the structural and electronic properties of the heterojunction.
Unraveling the thickness-dependent high photoconductivity in BaSnO3 thin films: insights from ultrafast charge carrier dynamics
Authors: Shrivastava Shikha , Kumar Kapil , Yadav Aditya , Nehra Simran , Srivastava Stuti , Singh Preetam , Kumar Mahesh , Gupta Govind , Dogra Anjana
Published: December 2024

Barium stannate, a perovskite-structured semiconductor, is gaining significant attention for its potential in high-performance UV photodetectors and optoelectronic applications. This study investigated the photo-response of epitaxial BaSnO3 (BSO) thin films grown using pulsed laser deposition. Our findings revealed an exceptionally high photo-response in BSO films having thicknesses (90, 270, and 360 nm). Detailed optical analyses were conducted to elucidate the photoconductive response’s mechanisms, including photoluminescence (PL), time-resolved PL, and the ultrafast transient spectroscopy. Notably, ultrafast transient spectroscopy was employed for the first time on this material. Leveraging BSO’s wide bandgap (3.4 eV), photoconductivity measurements in the UV range showed a peak responsivity of 5 A W−1 at 5 V with a 360 nm film and a response time of 470 ms. The transient spectroscopy reveals the thickness-dependent carrier dynamics, such as carrier relaxation, carrier trapping in mid-gap states, and recombination. Specifically, observed trapping times were approximately 6 ps for 360 nm thickness, 26 ps for 270 nm thickness, and 59 ps for 90 nm thickness of BSO thin film. This research enhances the understanding of the photoconductive behavior of barium stannate thin films and lays the groundwork for optimizing BSO-based UV-sensitive optoelectronic devices.
Physical insights into plasma-assisted methane reforming: microdischarge dynamics and diluent effects
Authors: Park Jin , Cha Min Suk
Published: December 2024

Dielectric barrier discharge (DBD) in fuel reforming processes has been widely investigated for its well-defined physical properties relevant to chemical kinetics and discharge physics, supporting the transition toward carbon-neutral society. However, a spatially and temporally resolved investigation of the physical and chemical aspects of plasma-assisted fuel reforming is essential to enhance our understanding and refine plasma kinetic mechanisms. In this study, we investigated the microscopic discharge characteristics in gas mixtures for partial oxidation (POx) and dry reforming of methane (DRM), focusing on the effects of N2 and Ar dilution on successive microdischarges. Using a pin-to-line electrode configuration, we found that organized, recurring microdischarge patterns were achievable only with N2 or Ar dilution, highlighting the crucial role of their excited metastable states in facilitating Penning ionization. For both POx and DRM mixtures, discharge power maintained consistently across N2 dilution ratios but decreased significantly as the Ar dilution ratio decreased. BOLSIG+ simulations attributed these trends to differences in electron energy loss to ionization and electronic excitation. Recognizing the importance of consistent temporal and spatial microdischarges for laser diagnostics, we mapped successive microdischarges characteristics as a function of applied voltage and frequency. These findings provide a foundational reference for future studies, enabling spatially and temporally resolved measurements of key parameters such as electric field intensity, electron density, temperature, and radical species. We plan to investigate CH3 and CH radicals using the same experimental setup to further advance our understanding of plasma-assisted reforming processes in the near future.
Bandgap reduction of bismuth tri-iodide via cesium tin iodide addition aimed toward lead-free solar cell applications
Authors: Anugrah Aditya Wahyu , Raifuku Itaru , Kawanishi Hidenori , Uraoka Yukiharu
Published: December 2024

Bismuth-based perovskites are promising materials for non-toxic solar cell applications owing to their air stability and high absorption coefficients. However, the wide bandgaps of bismuth-based perovskites limit their performance, rendering them unsuitable for single-junction solar cells. In this study, we successfully demonstrate that the bandgap of bismuth tri-iodide (BiI3) can be reduced by adding a mixture of CsI and SnI2 (CTI: cesium tin iodide). The addition of CTI changes the chemical states, surface morphology, optical properties, and energy-level structure of BiI3. The bandgap energy decreases from 1.75 eV (pure BiI3) to 1.41 eV (CTI added) as evidenced by UV–Vis spectrophotometry measurements. The valence band maximum (VBM) energy was estimated using photoemission yield spectroscopy (PYS). PYS measurements revealed that adding CTI to BiI3 lowered the VBM position. The bandgap narrowing mechanism was further explained by the band alignment, where the addition of CTI effectively adjusted the VBM and conduction band minimum positions to lower the energy levels. The device performance of the (CTI:BiI3) solar cells was investigated, and an improvement in power conversion efficiency was observed, mainly due to an enhancement in the open-circuit voltage and short-circuit current density.
Magnetic-proximity-induced anomalous Hall effect at the EuO/Sb2Te3 interface
Authors: Sinha Indraneel , Sinha Shreyashi , Naskar Subham , Manna Sujit
Published: December 2024

Time-reversal symmetry breaking of a topological insulator phase generates zero-field edge modes which are the hallmark of the quantum anomalous Hall effect (QAHE) and of possible value for dissipation-free switching or non-reciprocal microwave devices. But present material systems exhibiting the QAHE, such as magnetically doped bismuth telluride and twisted bilayer graphene, are intrinsically unstable, limiting their scalability. A pristine magnetic oxide at the surface of a TI would leave the TI structure intact and stabilize the TI surface, but epitaxy of an oxide on the lower-melting-point chalcogenide presents a particular challenge. Here we utilize pulsed laser deposition to grow (111)-oriented EuO on vacuum cleaved and annealed Sb2Te3(0001) surfaces. Under suitable growth conditions, we obtain a pristine interface and surface, as evidenced by x-ray reflectivity and scanning tunneling microscopy, respectively. Despite bulk transport in the thick (2 mm) Sb2Te3 layers, devices prepared for transport studies show a strong AHE, the necessary precursor to the QAHE. Our demonstration of EuO–Sb2Te3 epitaxy presents a scalable thin film approach to realize QAHE devices with radically improved chemical stability as compared to competing approaches.
Sheep-YOLO: a lightweight daily behavior identification and counting method for housed sheep
Authors: Wang Jie , Zhai Yahong , Zhu Lan , Xu Longyan , Zhao Yifan , Yuan Hongguang
Published: December 2024

Daily behavior detection and monitoring of sheep is crucial for assessing their health status. In recent years, computer vision has been widely used in livestock behavior detection, but it usually requires large memory and computational resources. In addition, most studies have focused only on the behavior of sheep during the day, while the behavior of sheep during the night is equally important for a comprehensive understanding of their health status and well-being. Therefore, in this study, we developed a lightweight daily behavior detection and counting method for housed sheep to detect lying, feeding, and standing behaviors, and to count the number of each behavior as well as the total number of sheep. First, we propose a new PCBAM module and incorporate it into the neck part of YOLOv8n to enhance the feature information contained in the feature map, second, we use the slim neck design paradigm incorporating GSConv to lighten and improve the model operation efficiency, and finally, we reconstruct the detection head to eliminate the redundant small target detection head, reduce the model computational burden, and improve the detection performance of medium and large targets. The Sheep-YOLO model is validated using the daily behavioral dataset of housed sheep, and the experimental results show that the improved model is effective in detecting sheep behavior in complex environments, and the mAP@0.5 is improved by 5.4% compared to the baseline model, and in particular, the lying and feeding behaviors of sheep are improved by 7.2% and 8.8%, respectively. Comparative experiments with other mainstream target detection algorithms validate the advantages of our proposed model for sheep behavior detection. This study provides an effective solution for behavioral detection and counting of housed sheep.