bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of the hot tail seeds for runaway electron generation during disruptions with lower hybrid waves in the HL-2A tokamak
Authors: Zhang Y. P. , Zou X. L. , Dong Y. B. , Bai X. Y. , Zhang J. , Ogawa K. , Gao J. M. , Cheng S. K. , Zhu Y. X. , Li B. , ji X. Q. , Liu Y. , Shi Z. B. , Zhong W. L. , Xu M.
Published: July 2023

The hot tail generation is expected to be the dominant mechanism for the runaway electron (RE) seed formation during disruptions, especially in large devices with high electron temperature such as international thermonuclear experimental reactor. This issue has been studied in the HL-2A tokamak by using the superthermal electrons produced by lower hybrid waves (LHWs), which can adjust the hot tail distribution. It was observed that RE generation was significantly enhanced during disruptions with LHWs. The measurements show that the multitudinous superthermal electrons with energy of 40–60 keV created by LHWs greatly transform the landscape of hot tail distribution. The tail electrons can be directly converted into REs under the acceleration of the high toroidal electric field during disruptions. Runaway current plateaus are more likely to be formed than in normal disruptions without LHWs. However, some abnormal phenomena have also been observed, that is, RE generation was not enhanced and no runaway current plateau was formed during some disruptions with LHWs. It is found that this is attributed to the complete loss of RE seeds caused by strong magnetic fluctuations, which prevents the generation of REs during disruptions. This may provide a way to avoid the generation of REs during disruptions by actively exciting magnetic fluctuations.
Resistance transient dynamics in switchable perovskite memristors
Authors: Bisquert Juan , Bou Agustín , Guerrero Antonio , Hernández-Balaguera Enrique
Published: July 2023

Memristor devices have been investigated for their properties of resistive modulation that can be used in data storage and brain-like computation elements as artificial synapses and neurons. Memristors are characterized by an onset of high current values under applied voltage that produces a transition to a low resistance state or successively to different stable states of increasing conductivity that implement synaptic weights. Here, we develop a nonlinear model to explain the variation with time of the voltage and the resistance and compare it to experimental results on ionic–electronic halide perovskite memristors. We find separate experimental signatures of the capacitive discharge and inductive current increase. We show that the capacitor produces an increase step of the resistance due to the influence of the series resistance. In contrast, the inductor feature associated with inverted hysteresis causes a decrease of the resistance, as observed experimentally. The chemical inductor feature dominates the potentiation effect in which the conductivity increases with the voltage stimulus. Our results enable a quantitative characterization of highly nonlinear electronic devices using a combination of techniques such as time transient decays and impedance spectroscopy.
Universal magnetic proximity effect in ferromagnet–semiconductor quantum well hybrid structures
Authors: Kalitukha I. V. , Yalcin E. , Ken O. S. , Korenev V. L. , Akimov I. A. , Harkort C. , Dimitriev G. S. , Kudlacik D. , Sapega V. F. , Nedelea V. , Zhukov E. A. , Yakovlev D. R. , Banshchikov A. G. , Kaveev A. K. , Karczewski G. , Wojtowicz T. , Müller M. , Bayer M.
Published: July 2023

Hybrid ferromagnet–semiconductor systems possess new outstanding properties, which emerge when bringing magnetic and semiconductor materials into contact. In such structures, the long-range magnetic proximity effect couples the spin systems of the ferromagnet and semiconductor on distances exceeding the carrier wave function overlap. The effect is due to the effective p–d exchange interaction of acceptor-bound holes in the quantum well with d-electrons of the ferromagnet. This indirect interaction is established via the phononic Stark effect mediated by the chiral phonons. Here, we demonstrate that the long-range magnetic proximity effect is universal and observed in hybrid structures with diverse magnetic components and potential barriers of various thicknesses and compositions. We study hybrid structures consisting of a semimetal (magnetite Fe3O4) or dielectric (spinel NiFe2O4) ferromagnet and a CdTe quantum well separated by a nonmagnetic (Cd,Mg)Te barrier. The proximity effect is manifested in the circular polarization of the photoluminescence corresponding to the recombination of photoexcited electrons with holes bound to shallow acceptors in the quantum well induced by magnetite or spinel itself, in contrast to interface ferromagnet in case of metal-based hybrid systems. A nontrivial dynamics of the proximity effect is observed in the studied structures due to recombination-induced dynamic polarization of electrons in the quantum well. It enables the determination of the exchange constant Δexch ≈ 70 μeV in a magnetite-based structure. The universal origin of the long-range exchange interaction along with the possibility of its electrical control offers prospects for the development of low-voltage spintronic devices compatible with existing solid-state electronics.
An overdamped Langevin approach to parallel diffusion and energy dissipation in the presence of low-frequency circularly polarized electromagnetic waves
Authors: Nariyuki Y.
Published: July 2023

Brownian motion of charged particles in the presence of low-frequency, circularly polarized electromagnetic waves is discussed. By using the wave rest frame, the Langevin system including low-frequency waves can be treated as a periodic system with a constant external force. In an overdamped limit, parallel diffusion is formulated by the Brownian motion whose diffusion coefficient includes wave amplitude. The nonequilibrium work by low-frequency waves satisfies a nonequilibrium relation corresponding to the fluctuation–dissipation relation with the effective temperature defined by wave amplitude.
Modulation of the magnetization and Gilbert damping in Heusler-alloy Co3–xFexAl thin films
Authors: Wang Ruifeng , Chen Xingtai , Yan Pengfei , Xu Yongkang , Zhang Yilin , Wang Jin , Fan Raymond , Bencok Peter , Steadman Paul , Li Yao , Zou Wenqin , Xu Yongbing , Liu Ronghua , Liu Wenqing , He Liang
Published: July 2023

The saturated magnetization (mtot) and the Gilbert damping constant (α) are the two key factors that determine the critical current density of the magnetization reversal in the spin-transfer-torque magnetic memory devices. Here, this study demonstrates the efficient modulation of these two parameters by tunning the composition of the Heusler Co3–xFexAl thin films, utilizing the x-ray magnetic circular dichroism technique and ferromagnetic resonance measurements. With the increase in Fe concentration, the mtot shows a downward trend mainly resulting from the decrease in Fe local magnetic moment instead of Co. On the other hand, the ultralow α decreases from 0.004 to 0.0012. This has been attributed to the reduction in the spin–orbit coupling, which is corroborated by the decrease in the orbit-to-spin moment ratio. Our findings add a building block for the Heusler compounds with tunable Gilbert damping and appropriate magnetization and show great potential in spintronic applications.
Effective thermal diffusivity and conductivity of a fluid-saturated solid foam
Authors: Sgreva Nicolò R. , Jannot Yves , Métivier Christel
Published: July 2023

The thermal properties of composite materials, such as fluid-saturated solid foams, can be estimated in two ways: using equivalent models based on both the thermal properties of the liquid and solid phases or by direct measurements, which, however, are not always straightforward. In this paper, we provide a new experimental device based on the four-layer (4L) method to measure the effective thermal diffusivity of a solid foam filled with different fluids (glycerol and water). The specific heat of the solid part is measured using differential scanning calorimetry, and the volumetric heat capacity of the composite system is estimated using an additive law. The effective thermal conductivity deduced from experiments is then compared with the maximum and minimum values obtained from the parallel and series equivalent models. The proposed 4L method is first validated by measuring the thermal diffusivity of pure water and then used afterward to measure the effective thermal diffusivity of the fluid-saturated foam. Experimental results converge with those obtained from equivalent models in the case where the different components of the system have similar thermal conductivities (e.g., glycerol-saturated foam). On the other hand, when the liquid and solid phases have very different thermal properties (e.g., water-saturated foam), the experimental results differ from what equivalent models predict. This highlights the need to make appropriate experimental measurements to estimate the overall thermal properties of these latter multicomponent systems or to consider more realistic equivalent models.
Wideband switchable linear polarization rotator based on metasurface
Authors: Wang Ping , Qin Yifei , Wang Yu , Zhou Hongcheng , Yan Zhongming
Published: July 2023

The realization of dynamic polarization rotation based on the metamaterial or metasurface is always a concerned issue in electromagnetic manipulation. In this Letter, a transmission-type switchable metasurface is proposed, which can rotate the linear polarized (LP) wave to arbitrary angle among ±45° in a wide frequency band. The polarization rotation metasurface (PRM) consists of a polarization conversion surface and a partially reflective surface. By controlling the resistances of PIN diodes, the PRM can change the polarization angle of transmitted LP wave. To verify the design, a prototype of the proposed PRM is fabricated and tested, and the simulated and measured results are in good agreement. According to the measured results, the fractional bandwidth at each state of prototype is larger than 20.4%. The overlapping operational band of the prototype is from 3.03 to 3.60 GHz, where the transmission coefficient remains higher than –2 dB, and the axial ratio of transmitted wave is higher than 15 dB. The proposed design may have the application potential in target detection, wireless communication, and polarimetric imaging.
Kinetics of the fast ionization waves with runaway electrons
Authors: Levko Dmitry , Raja Laxminarayan L.
Published: July 2023

In nanosecond gas breakdown, runaway electrons are responsible for the interelectrode space pre-ionization, which supports the propagation of fast ionization waves or streamers. However, a detailed understanding of mechanisms of how this happens is still elusive because of the wide range of energies of runaway electrons, from the hundreds of eV to the hundreds of keV. While the low-energy part of the runaway electron population can only ionize the background gas, the high-energy part can produce x-rays that can also ionize the gas. The objective of this paper is to understand the influence of different electron groups on the fast ionization wave dynamics for the conditions typical for runaway electrons generation. We find that there are two main groups, one having energies below 100 eV and another having energies above 1 keV. The first group defines the establishment of the fast ionization waves and their plasma parameters, while the second group defines the speed of the ionization front propagation.
Mode-coupling theory for mixtures of athermal self-propelled particles
Authors: Debets Vincent E. , Janssen Liesbeth M. C.
Published: July 2023

Dense or glassy active matter, as a result of its remarkable resemblance to passive glass-forming materials, is enjoying increasing scientific interest. To better grasp the subtle effect of active motion on the process of vitrification, a number of active mode-coupling theories (MCTs) have recently been developed. These have proven capable of qualitatively predicting important parts of the active glassy phenomenology. However, most efforts so far have only considered single-component materials, and their derivations are arguably more complex than the standard MCT case, which might hinder broader usage. Here we present a detailed derivation of a distinct active MCT for mixtures of athermal self-propelled particles that is more transparent than previously introduced versions. The key insight is that we can follow a similar strategy for our overdamped active system as is typically used for passive underdamped MCT. Interestingly, when only considering one particle species, our theory gives the exact same result as the one obtained in previous work, which employed a highly different mode-coupling strategy. Moreover, we assess the quality of the theory and its novel extension to multi-component materials by using it to predict the dynamics of a Kob–Andersen mixture of athermal active Brownian quasi-hard spheres. We demonstrate that our theory is able to capture all qualitative features, most notably the location of the optimum of the dynamics when the persistence length and cage length coincide, for each combination of particle types.
Testing high-resolution transverse profile monitors by measuring the dependence of the electron beam size on the beam energy at SwissFEL
Authors: Juranić Pavle , Prat Eduard
Published: July 2023

Transverse profile monitors are essential devices to characterize particle beams in accelerators. Here, we present an improved design of beam profile monitors at SwissFEL that combines the use of high-quality filters and dynamic focusing. We reconstruct the profile monitor resolution in a gentle way by measuring the electron beam size for different energies. The results show a significant improvement of the new design compared to the previous version, from 20 to 14 µm.
High-performance full-Stokes polarization detection at exceptional point in a non-Hermitian metasurface
Authors: Gao Fan , Jin Guoli , Liu Hao , Zhou Jian , Deng Juan , Yan Bo
Published: July 2023

Polarization and its detection have attracted tremendous attention due to the rich information it provides and the practical applications it enables. Here, we propose a high-performance reflective pixelated metasurface with full-Stokes detection in the visible wavelength, which integrates both linear polarization (LP) and circular polarization (CP) filters on one platform. The system achieves a high extinction ratio for CP incidence in a non-Hermitian system, generated from the exceptional point (EP) effect. With integrated LP filters, full-Stokes detection can be obtained with accuracy and efficiency in real time. The EP-based innovation also promises other practical applications, such as polarization imaging technologies and optical computing.
Combining machine learning and molecular simulations to predict the stability of amorphous drugs
Authors: Barnard Trent , Sosso Gabriele C.
Published: July 2023

Amorphous drugs represent an intriguing option to bypass the low solubility of many crystalline formulations of pharmaceuticals. The physical stability of the amorphous phase with respect to the crystal is crucial to bring amorphous formulations into the market—however, predicting the timescale involved with the onset of crystallization a priori is a formidably challenging task. Machine learning can help in this context by crafting models capable of predicting the physical stability of any given amorphous drug. In this work, we leverage the outcomes of molecular dynamics simulations to further the state-of-the-art. In particular, we devise, compute, and use “solid state” descriptors that capture the dynamical properties of the amorphous phases, thus complementing the picture offered by the “traditional,” “one-molecule” descriptors used in most quantitative structure–activity relationship models. The results in terms of accuracy are very encouraging and demonstrate the added value of using molecular simulations as a tool to enrich the traditional machine learning paradigm for drug design and discovery.
Experimental investigation of field distributions for chirped fiber Bragg grating
Authors: Kang Weide , Wu Qiang , Cao Yulong , Wang Xinger , Cao Kaixiang , Gao Lei , Zhu Tao
Published: July 2023

Chirped fiber Bragg gratings (CFBGs) are used in applications ranging from fiber optic communication, optical fiber sensing, to optical information processing, among which the field distributions are vital in improving their performance. Here, we investigate the optical field distributions of CFBGs based on the finite element method and experimentally verify the evanescent field distribution properties of a CFBG fabricated by ultraviolet exposure method based on an InGaAs linear image sensor. From the simulation, we can find that the reflective locations of the evanescent field and the internal field distributions move linearly along the fiber grating region as the incident wavelength increases. A slight difference that was found for the evanescent field was that the intensity for areas far away from the reflective region diminishes gradually. The obtained experimental data are fully consistent with that obtained from the simulation. The exploration of the field distributions of CFBGs is expected to provide more information for the subsequent analysis of fiber grating fields, the investigation of material refractive index modulation mechanism during grating fabrication, the fabrication of special fiber gratings, and so on.
Coherent two-dimensional THz magnetic resonance spectroscopies for molecular magnets: Analysis of Dzyaloshinskii–Moriya interaction
Authors: Zhang Jiaji , Tanimura Yoshitaka
Published: July 2023

To investigate the novel quantum dynamic behaviors of magnetic materials that arise from complex spin–spin interactions, it is necessary to probe the magnetic response at a speed greater than the spin-relaxation and dephasing processes. Recently developed two-dimensional (2D) terahertz magnetic resonance (THz-MR) spectroscopy techniques use the magnetic components of laser pulses, and this allows investigation of the details of the ultrafast dynamics of spin systems. For such investigations, quantum treatment—not only of the spin system itself but also of the environment surrounding the spin system—is important. In our method, based on the theory of multidimensional optical spectroscopy, we formulate nonlinear THz-MR spectra using an approach based on the numerically rigorous hierarchical equations of motion. We conduct numerical calculations of both linear (1D) and 2D THz-MR spectra for a linear chiral spin chain. The pitch and direction of chirality (clockwise or anticlockwise) are determined by the strength and sign of the Dzyaloshinskii–Moriya interaction (DMI). We show that not only the strength but also the sign of the DMI can be evaluated through the use of 2D THz-MR spectroscopic measurements, while 1D measurements allow us to determine only the strength.
Initial progress of the magnetic diagnostics of the MAST-U tokamak
Authors: Ryan D. A. , Martin R. , Appel L. , Ayed N. B. , Kogan L. , Kirk A. ,   MAST Upgrade Team
Published: July 2023

MAST Upgrade has just begun its third physics campaign in April of 2023. The set of magnetic probes used to diagnose the magnetic field and currents on MAST Upgrade are described, and their calibration procedures are outlined including calculation of uncertainties. The median uncertainty in the calibration factors of the flux loops and pickup coils are calculated as 1.7% and 6.3%. The arrays of installed instability diagnostics are described, and the detection and diagnosis of a specimen MHD mode are demonstrated. Plans for the improvement of the magnetics arrays are outlined.
V2CTx gas sensor based on memristive effect with ultrafast SO2 detection
Authors: Guo Liangchao , Han Haoran , Li Yi , Ye Chen , Cui Junfeng , Zheng Chaoyue , Ding Guanglong , Zhai Yongbiao , Zhou Ye , Zhang Chao
Published: July 2023

As a commonly harmful product produced in industrial production, the sensitive detection of SO2 is a crucial safety consideration with adverse impacts on human health. However, constructing MXene-based gas sensors for rapid detection at room temperature is still challenging. In this work, we demonstrate a V2CTx gasistor (gas memristor) with a millisecond-level cycle (360 ms) for SO2 ultrafast detection, and meanwhile, the function of gas response and memory is realized. Specifically, the synaptic plasticity of paired-pulse facilitation (PPF) behavior has been applied to identify the different types of gases instead of gas sensitivity. Consistent with gas response performance, the gasistor displays the highest pulse-controlled PPF ratio (210.4%) under 10 ms electric pulse interval for 10 ppm SO2, 1.34 times that under air. Also, the V2CTx gasistor exhibits excellent repeatability and good stability. Furthermore, this strategy provides a great application prospect in rapid detection and medical treatment for toxic gases and artificial sensing memory.
Multiple solutions in magnetohydrodynamic stagnation flow of hybrid nanofluid past a sheet with mathematical chemical reactions model and stability analysis
Authors: Ahmed Sohail , Ishaq Muhammad
Published: July 2023

The homogeneous heterogeneous reactions (H–H reactions) in the magnetohydrodynamic (MHD) boundary layer stagnated flow of an Al2O3–Cu–water base hybrid nanofluid past a stretching shrinking sheet are studied. A newly developed two-phase hybrid nanofluid model based on Buongiorno's model is used to understand the nanofluids behaviors. Multiple solutions are observed for specific ranges of various parameters, whose stabilities are checked and discussed, which seem to have been neglected in previously published articles about studies of MHD-stagnation flow and mathematical chemical reactions models using hybrid nanofluid. The heterogeneous reaction considered in this case is isothermal and first order, whereas the homogeneous chemical reaction is isothermal cubic autocatalytic. The solutions so captured are examined using various graphs to demonstrate the impact of different physical parameters, and their physical insights are also given. The results show that hybrid nanofluids, which have distinct functions in the processes of homogeneous and heterogeneous reactions, play a key role in the homogeneous–heterogeneous reactions' transport mechanism. The quadratic multiple regression analysis evaluations of the local Nusselt number demonstrate that the thermophoretic impact predominates over Brownian motion for both magnetic and non-magnetic effects.
Improved energy storage performance in rare-earth modified lead-free BNT-based relaxor ferroelectric ceramics
Authors: Bin Chengwen , Hou Xu , Liao Luocheng , Liu Yuwen , Yang Han , Liu Yunya , Wang Jie
Published: July 2023

Dielectric ceramic capacitors with high energy storage performance are indispensable components in high-power pulse electronic systems. Herein, a collaborative optimization design is employed to achieve excellent energy storage performance in rare-earth oxides modified 0.76(0.94Bi0.5Na0.5TiO3-0.06BaTiO3)-0.24Sr0.7Bi0.2TiO3 (BNBT-SBT) ceramics by simultaneously enhancing the breakdown field strength (Eb) and relaxor behavior. To this end, ferroelectric domains are partially transformed into polar nanoregions by introducing relaxor ferroelectric SBT, while a smaller grain size is produced by doping rare-earth elements to improve the Eb and further disrupt the long-range order of ferroelectric polarization. It is found that the La-doped BNBT-SBT ceramic simultaneously exhibits a superior energy storage density of 4.4 J cm−3 and an ultrahigh efficiency of ∼91% under a moderate electric field of 300 kV/cm. The good temperature stability (30–120 °C), frequency endurance (1–100 Hz), electric fatigue resistance (1–106 cycles), and excellent power density (108 MW cm−3) are also obtained in the lead-free Bi0.5Na0.5TiO3-based relaxor ferroelectric ceramics. These prominent properties indicate that the La-doped BNBT-SBT ceramic is a promising candidate for applications of high-energy storage capacitors.
Impact of hybrid surfaces on the droplet breakup dynamics in microgravity slug flow: A dynamic contact angle analysis
Authors: Mousavi S Mahmood , Jarrahbashi Dorrin , Karimi Nader , Faroughi Salah A
Published: July 2023

Microfluidic devices, which enable precise control and manipulation of fluids at the microscale, have revolutionized various fields, including chemical synthesis and space technology. A comprehensive understanding of fluid behavior under diverse conditions, particularly in microgravity, is essential for optimizing the design and performance of these devices. This paper aims to investigate the effects of discontinuous wettability on droplet breakup structures under microgravity conditions using a microchannel wall. The approach we adopt is underpinned by the volume-of-fluid methodology, an efficient technique renowned for its accurate resolution of the fluid interface in a two-phase flow. Furthermore, a modified dynamic contact angle model is employed to precisely predict the shape of the droplet interface at and near the wall. Our comprehensive model considers influential parameters such as slug length and droplet generation frequency, thereby providing crucial insights into their impact on the two-phase interface velocity. Validated against existing literature data, our model explores the impact of various configurations of discontinuous wettability on breakup morphology. Our findings highlight the significance of employing a dynamic contact angle methodology for making accurate predictions of droplet shape, which is influenced by the wall contact angle. Emphasis is placed particularly on the effects of slug length and droplet generation frequency. Notably, we demonstrate that the use of a hybrid surface at the junction section allows for precise control over the shape and size of the daughter droplets, contrasting with the symmetrical division observed on uniformly hydrophilic or superhydrophobic surfaces. This study contributes valuable insights into the complex dynamics of the droplet breakup process, which has profound implications for the design and optimization of microfluidic devices operating under microgravity conditions. Such insights are further poised to augment applications in space exploration, microreactors, and more.
PhotoCORMs based on zinc(ii)-flavonol derivatives with superior biological properties for use in living organisms
Authors: Sun Le , An Siying , Wei Dong , Zhang Ronglan , Zhao Jianshe
Published: July 2023

CO is an important gas signal molecule and plays an indispensable role in the maintenance of cell homeostasis. Herein, photoinduced CO-releasing molecules (photoCORMs), that combine the effects of zinc(ii) and different ligands including flavonol derivatives and tripod pyridyl compounds, are reported. The photoCORMs can release about one equivalent of CO, and the solid samples are stabile for more than 90 days in air. Cytotoxicity tests suggest that photoCORMs possess low toxicity and have the potential to be used in organisms. The intracellular uptake and photoreactivity of photoCORM 3a, with low toxicity and a rapid CO-release rate, were studied in HeLa cells. The results indicate that 3a could successfully penetrate the cell membrane and enter the cytoplasm. More importantly, it is further demonstrated that 3a can successfully release CO in HeLa cells, which is detected using intracellular CO sensors. Based on the cell study, the same result was found when the photoinduced CO release of 3a in Kunming mice was studied utilizing a carboxyhemoglobin kit. This study is of great significance for the development of new valuable CO donors that can be applied to organisms to exert their biological effects.
Coordination of apicoplast transcription in a malaria parasite by internal and host cues
Authors: Kobayashi Yuki , Komatsuya Keisuke , Imamura Sousuke , Nozaki Tomoyoshi , Watanabe Yoh-ichi , Sato Shigeharu , Dodd Antony N. , Kita Kiyoshi , Tanaka Kan
Published: July 2023

The malaria parasite
Plasmodium falciparum
has a nonphotosynthetic plastid called the apicoplast, which contains its own genome. Regulatory mechanisms for apicoplast gene expression remain poorly understood, despite this organelle being crucial for the parasite life cycle. Here, we identify a nuclear-encoded apicoplast RNA polymerase σ subunit (sigma factor) which, along with the α subunit, appears to mediate apicoplast transcript accumulation. This has a periodicity reminiscent of parasite circadian or developmental control. Expression of the apicoplast subunit gene,
apSig
, together with apicoplast transcripts, increased in the presence of the blood circadian signaling hormone melatonin. Our data suggest that the host circadian rhythm is integrated with intrinsic parasite cues to coordinate apicoplast genome transcription. This evolutionarily conserved regulatory system might be a future target for malaria treatment.
Inhibition of neutral sphingomyelinase 2 impairs HIV-1 envelope formation and substantially delays or eliminates viral rebound
Authors: Yoo Seung-Wan , Waheed Abdul A. , Deme Pragney , Tohumeken Sehmus , Rais Rana , Smith Matthew D. , DeMarino Catherine , Calabresi Peter A. , Kashanchi Fatah , Freed Eric O. , Slusher Barbara S. , Haughey Norman J.
Published: July 2023

Although HIV-1 Gag is known to drive viral assembly and budding, the precise mechanisms by which the lipid composition of the plasma membrane is remodeled during assembly are incompletely understood. Here, we provide evidence that the sphingomyelin hydrolase neutral sphingomyelinase 2 (nSMase2) interacts with HIV-1 Gag and through the hydrolysis of sphingomyelin creates ceramide that is necessary for proper formation of the viral envelope and viral maturation. Inhibition or depletion of nSMase2 resulted in the production of noninfectious HIV-1 virions with incomplete Gag lattices lacking condensed conical cores. Inhibition of nSMase2 in HIV-1-infected humanized mouse models with a potent and selective inhibitor of nSMase2 termed PDDC [phenyl(R)-(1-(3-(3,4-dimethoxyphenyl)-2, 6-dimethylimidazo[1,2-b]pyridazin-8-yl) pyrrolidin-3-yl)-carbamate] produced a linear reduction in levels of HIV-1 in plasma. If undetectable plasma levels of HIV-1 were achieved with PDDC treatment, viral rebound did not occur for up to 4 wk when PDDC was discontinued. In vivo and tissue culture results suggest that PDDC selectively kills cells with actively replicating HIV-1. Collectively, this work demonstrates that nSMase2 is a critical regulator of HIV-1 replication and suggests that nSMase2 could be an important therapeutic target with the potential to kill HIV-1-infected cells.
EMT activates exocytotic Rabs to coordinate invasion and immunosuppression in lung cancer
Authors: Xiao Guan-Yu , Tan Xiaochao , Rodriguez Bertha L. , Gibbons Don L. , Wang Shike , Wu Chao , Liu Xin , Yu Jiang , Vasquez Mayra E. , Tran Hai T. , Xu Jun , Russell William K. , Haymaker Cara , Lee Younghee , Zhang Jianjun , Solis Luisa , Wistuba Ignacio I. , Kurie Jonathan M.
Published: July 2023

Epithelial-to-mesenchymal transition (EMT) underlies immunosuppression, drug resistance, and metastasis in epithelial malignancies. However, the way in which EMT orchestrates disparate biological processes remains unclear. Here, we identify an EMT-activated vesicular trafficking network that coordinates promigratory focal adhesion dynamics with an immunosuppressive secretory program in lung adenocarcinoma (LUAD). The EMT-activating transcription factor ZEB1 drives exocytotic vesicular trafficking by relieving Rab6A, Rab8A, and guanine nucleotide exchange factors from miR-148a-dependent silencing, thereby facilitating MMP14-dependent focal adhesion turnover in LUAD cells and autotaxin-mediated CD8+T cell exhaustion, indicating that cell-intrinsic and extrinsic processes are linked through a microRNA that coordinates vesicular trafficking networks. Blockade of ZEB1-dependent secretion reactivates antitumor immunity and negates resistance to PD-L1 immune checkpoint blockade, an important clinical problem in LUAD. Thus, EMT activates exocytotic Rabs to drive a secretory program that promotes invasion and immunosuppression in LUAD.
Recycling of bacterial RNA polymerase by the Swi2/Snf2 ATPase RapA
Authors: Inlow Koe , Tenenbaum Debora , Friedman Larry J. , Kondev Jane , Gelles Jeff
Published: July 2023

Free-living bacteria have regulatory systems that can quickly reprogram gene transcription in response to changes in the cellular environment. The RapA ATPase, a prokaryotic homolog of the eukaryotic Swi2/Snf2 chromatin remodeling complex, may facilitate such reprogramming, but the mechanisms by which it does so are unclear. We used multiwavelength single-molecule fluorescence microscopy in vitro to examine RapA function in the
Escherichia coli
transcription cycle. In our experiments, RapA at <5 nM concentration did not appear to alter transcription initiation, elongation, or intrinsic termination. Instead, we directly observed a single RapA molecule bind specifically to the kinetically stable post termination complex (PTC)—consisting of core RNA polymerase (RNAP)-bound sequence nonspecifically to double-stranded DNA—and efficiently remove RNAP from DNA within seconds in an ATP-hydrolysis-dependent reaction. Kinetic analysis elucidates the process through which RapA locates the PTC and the key mechanistic intermediates that bind and hydrolyze ATP. This study defines how RapA participates in the transcription cycle between termination and initiation and suggests that RapA helps set the balance between global RNAP recycling and local transcription reinitiation in proteobacterial genomes.
Emergent programmable behavior and chaos in dynamically driven active filaments
Authors: Krishnamurthy Deepak , Prakash Manu
Published: July 2023

How the behavior of cells emerges from their constituent subcellular biochemical and physical parts is an outstanding challenge at the intersection of biology and physics. A remarkable example of single-cell behavior occurs in the ciliate
Lacrymaria olor
, which hunts for its prey via rapid movements and protrusions of a slender neck, many times the size of the original cell body. The dynamics of this cell neck is powered by a coat of cilia across its length and tip. How a cell can program this active filamentous structure to produce desirable behaviors like search and homing to a target remains unknown. Here, we present an active filament model that allows us to uncover how a “program” (time sequence of active forcing) leads to “behavior” (filament shape dynamics). Our model captures two key features of this system—time-varying activity patterns (extension and compression cycles) and active stresses that are uniquely aligned with the filament geometry—a “follower force” constraint. We show that active filaments under deterministic, time-varying follower forces display rich behaviors including periodic and aperiodic dynamics over long times. We further show that aperiodicity occurs due to a transition to chaos in regions of a biologically accessible parameter space. We also identify a simple nonlinear iterated map of filament shape that approximately predicts long-term behavior suggesting simple, artificial “programs” for filament functions such as homing and searching space. Last, we directly measure the statistical properties of biological programs in
L. olor
, enabling comparisons between model predictions and experiments.
The role of musical improvisation in the development of creative thinking in children (El rol de la improvisación musical en el desarrollo del pensamiento creativo infantil)
Authors: Zhang Chunfeng
Published: July 2023

This study examines the role of musical improvisation in the development of creative thinking in children studying at Harbin No. 3 Secondary School (Harbin, Heilongjiang Province, China). The creative thinking of two groups (experimental and control) was examined through pre- and post-tests aimed at musical creativity measurement and assessing the effectiveness of musical improvisation in the development of musical creativity. The post-test mean and standard deviations of each musical creativity factor in the experimental group showed an increase in four factors: musical extensiveness (by 65%), musical flexibility (by 37%), musical originality (by 34%) and musical syntax (by 42%). All correlations between the MCTM factors were significant ( p < .01), demonstrating that the four factors are representative of creative thinking. The research is of practical and scientific significance as it proves the factor of the influence of musical improvisation on the development of creative skills in children. The research results can be applied by schools and other educational institutions that are interested in increasing the indicators of creativity of their students.
Friction stir welding: Process, temperature, microstructure and properties
Authors: Liu Huihong , Morisada Yoshiaki , Fujii Hidetoshi
Published: July 2023

As an energy-efficient solid-state joining technique, friction stir welding (FSW) shows enormous advantages compared to conventional fusion welding methods. This work comprehensively reviewed the recent studies on FSW of commonly-used metals including Al, Mg, Fe, Ti and their alloys, with a particular focus on thermal cycles experienced during FSW. The role played by thermal cycles was comparatively summarised for different metals, trying not only to understand the physical effect of welding conditions on joints’ microstructural evolution and mechanical properties, but also provide a guide for engineers to take proper FSW strategies when facing different metals, which has not been discussed in detail in other reviews. Finally, several ideas were proposed for a possible advancement in FSW of the investigated metals.
Exploring the Psychosocial and Wellbeing Needs of Staff Accessing Trauma Support in Forensic Mental Health Services in the UK: Relations with Demographic, Occupational and Trauma Event Characteristics
Authors: Morris Deborah J. , Webb Elanor Lucy , Worsfold Jemima , Greenwood Annette
Published: July 2023

Healthcare professionals in secure psychiatric services are frequently exposed to service user distress and aggression. Consequently, staff trauma services (STS) have been developed to mitigate the detrimental impact of these experiences. Whilst the increased focus on occupational wellbeing is welcomed, such services have typically evolved in the absence of robust investigations exploring the breadth of the trauma-related needs of healthcare professionals (HCPs). This study explored the profiles of staff referred to an STS and the sequelea of physical and psychological incidents, with a view to improving understanding of need and informing the provision of STSs. Retrospective analyses of demographic characteristics, incident details and psychosocial impacts were conducted. Participants were staff from a secure psychiatric hospital who had received 1:1 support from a dedicated STS. Overall, approximately 4.6% (n = 154) of the workforce accessed the STS. Both clinical (n = 142, 92.2%) and non-clinical staff (n = 12, 7.8%) received support for physical and psychological incidents, occurring in and outside of the workplace. Compared to the general UK population, people who were referred to the STS were less likely to have social support. Staff most frequently accessed the service for work-based physical (n = 65, 42.2%) and psychological (n = 63, 40.9%) incidents. Whilst staff referred following a psychological incident were less likely to be absent from work, they presented with significantly higher levels of psychological distress. This study provides novel insight into factors associated with adverse psychosocial outcomes following trauma exposure, in an understudied occupational population.
Nonlinear Photocurrent Responses in Janus WSSe Monolayer
Authors: Chen Meng , Yu Sheng-Bin , Zhang Dong , Li Jun
Published: July 2023

Janus WSSe monolayer is a novel two-dimensional (2D) material that breaks the out-of-plane mirror symmetry and has a large built-in electric field. These features lead to sizable Rashba spin-orbit coupling and enhanced nonlinear optical properties, making it a promising material platform for various spintronic and optoelectronic device applications. In recent years, nonlinear photocurrent responses such as shift and injection currents were found to be closely related to the quantum geometry and Berry curvature of materials, indicating that these responses can serve as powerful tools for probing the novel quantum properties of materials. In this work, we investigate the second-order nonlinear photocurrent responses in a Janus WSSe monolayer theoretically based on first-principles calculations and the Wannier interpolation method. It is demonstrated that the Janus WSSe monolayer exhibits significant out-of-plane nonlinear photocurrent coefficients, which is distinct from the non-Janus structures. Our results also suggest that the second-order nonlinear photocurrent response in the Janus WSSe monolayer can be effectively tuned by biaxial strain or an external electric field. Thus, the Janus WSSe monolayer offers a unique opportunity for both exploring nonlinear optical phenomena and realizing flexible 2D optoelectronic nanodevices.
Gluing variations
Authors: Chruściel Piotr T , Cong Wan
Published: July 2023

We establish several results on gluing/embedding/extending geometric structures in vacuum spacetimes with a cosmological constant in any spacetime dimensions

d
⩾
4

, with emphasis on characteristic data. A useful tool is provided by the notion of submanifold-data of order k. As an application of our methods we prove that vacuum Cauchy data on a spacelike Cauchy surface with boundary can always be extended to vacuum data defined beyond the boundary.
Spinorial Wheeler–DeWitt wave functions inside black hole horizons
Authors: Kan Nahomi , Aoyama Takuma , Shiraishi Kiyoshi
Published: July 2023

We revisit the solutions of the Wheeler–DeWitt (WDW) equation inside the horizons of spherical black holes and planar topological black holes in arbitrary dimensions. For these systems, the solutions of the equations are found to have the same form. Therefore, Yeom’s Annihilation-to-nothing interpretation can be applied to each case. We have introduced the Dirac-type WDW equations into quantum cosmology in a recent paper, so we also apply our formulation to the quantum theory of the interior of the black hole in order to obtain the solution of the spinorial wave function. The shape of the wave packet of the spinorial WDW wave function indicates that the variation of Yeom’s interpretation holds in this scheme.
Crosstalk-free large aperture electromagnetic 2D micromirror for LiDAR application
Authors: Ghazinouri Behrad , He Siyuan
Published: July 2023

This paper presents a novel design of a 2D electromagnetic micromirror without crosstalk. The proposed micromirror uses a flexible printed circuit board (FPCB) and four layers of coils embedded in the polyimide layers. The insulated layers of the coil allow for independent actuation of the mirror plate to rotate about two orthogonal axes. The diamond shaped micromirror uses a hyperbola-shaped magnetic field on the coils under the mirror plate and a 45-degrees magnetic field on the coils embedded in the FPCB frame to eliminate the mechanical crosstalk. Finite element analysis was used to predict the novel 2D micromirror’s behavior. The novel 2D micromirror prototype is used in scanning LiDAR, The results indicate that the crosstalk-free pattern yielded significantly clearer results, particularly for detecting object boundaries and reducing barrel distortion. The experimental test has verified the novel crosstalk-free 2D micromirror working principle and showed good scanning quality: no crosstalk and an improvement in the horizontal field of view up to 19% But with the cost of reducing the vertical field of view by up to 12%. The novel 2D micromirror prototype has a large aperture of 19 × 19 mm2, which is very suitable for coaxial scanning LiDAR.
Triple differential cross sections for single ionization of an atom by bare ion impact
Authors: Purkait K , Mondal M , Haque A , Mandal B , Purkait M
Published: July 2023

We present triple differential cross sections (TDCSs) for single ionization of atoms by proton and highly charged bare ions impact by means of the three-body formalism of the first Born, two-Coulomb wave and three-Coulomb (3C) wave (3CW) methods, respectively. The TDCS has been calculated both in the scattering and perpendicular planes. The purpose of this work is to investigate the validity of different methods as well as the role of interaction between projectile and residual-target-ion in the final state for weak perturbation strength with low electron emission energy at several momentum transfers. By comparing our calculations with experimental data, overall, the 3CW predicts better agreement with experiments than other calculations in the scattering plane. In the perpendicular plane, all calculations deviate from experimental data with increasing transverse momentum transfer for p − He collision. At low momentum transfer, the location of binary peak obtained by the first Born approximation calculation is well established with the experiment for proton impact. On the other hand, the 3CW model is in much better agreement with experiments, both in absolute values and peak position for highly charged impact. Finally, the strong influence of the internuclear Coulomb distortion on TDCS has been observed at low and intermediate momentum transfer.
Synthetically encapsulated & self-organized transition metal oxide nano-structures inside carbon nanotubes as robust: Li-ion battery anode materials
Authors: Kapoor Aakanksha , Patrike Apurva L , Singh Nitesh , Thauer Elisa , Ottmann Alexander , Klingeler Rüdiger , Ogale Satishchandra , Bajpai Ashna
Published: July 2023

We report a comparative study on the electrochemical performance of four different transition metal oxides encapsulated inside carbon nanotubes (oxides@CNT), along with reference data obtained on a bare-oxide. A key result here is that the encapsulation leads to superior cyclic stability, irrespective of the type of the oxide-encapsulate. This comparison also enables us to isolate the advantages associated with the encapsulation of oxide within the core cavity of CNT, as opposed to the case of oxide/CNT composites, in which oxide resides outside the CNT. Innovative use of camphor during sample synthesis enables precise control over the morphology of the filled CNT, which can either be in aligned-forest or in entangled geometry. The morphology appears to play a crucial role in tuning the magnitude of the specific capacity, whereas the encapsulation relates to the cyclic stability. Overall, the electrochemical data on various oxides@CNT bring forward interesting inferences pertaining to the morphology, filling fraction of the oxide-encapsulate, and the presence of oxide nano-particles adhering outside the CNT. Our results provide useful pointers for optimization of these critical parameters, thus paving the way for oxide@CNT for practical electrochemical applications.