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Dynamic experiment and numerical simulation of frozen soil under confining pressure

Acta Mechanica Sinica 2020年第6期36卷 1302-1318,I0004页

作者： w.R.Tang z.w.zhu T.T.Fu z.w.zhou z.H.Shanggua Applied Mechanics and Structural Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiaotong UniversityChengdu610036China Northwest Institute of Eco-Environment and Resources State Key Laboratory of Frozen Soil EngineeringChinese Academy of SciencesLanzhou730000China

with the development of cold region engineering,it is crucial to study the mechanical properties of frozen *** practice,frozen soil is inevitably subject to impact loading,making the study of frozen soil under impact loading necessary for engineering in cold *** split–Hopkinson pressure bar(SHPB)is an important experimental means for obtaining the dynamic performance of *** this study,an SHPB experiment was conducted on frozen soil under confining *** frozen soil exhibited an evident strain rate effect and temperature effect under confining *** SHPB experiment on frozen soil under confining pressure was simulated numerically using LS-DYNA software and the Holmquist–Johnson–Cook(HJC)material model.A loading simulation with passive confining pressure and active confining pressure was completed by adding an aluminum sleeve and applying a constant *** simulation results obtained using the above methods were in good agreement with the experimental *** strength of the frozen soil under confining pressure was greater than that of the uniaxial impact,and there was an evident confining pressure ***,the confining pressure provided by passive confinement was larger than that provided by active *** passive confining pressure energy absorption efficiency was higher than for the active confining pressure due to the need to absorb more energy under the same damage *** frozen soil exhibited viscoplastic failure characteristics under confining pressure.

关键词： Frozen soil-Dynamic experiment Confining pressure Split-Hopkinson pressure bar Numerical simulation

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Precipitation of multi-type nano-quasicrystals in a Mg-zn-Y alloy

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Journal of Magnesium and Alloys 2024年第3期12卷 997-1008页

作者： w.z.wang X.z.zhou L.F.zhang H.Q.Ye z.Q.Yang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China Ji Hua Laboratory Foshan 528251China Foshan University Foshan 528231China

Mg-6zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging *** evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy *** new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral ***-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A shell composed of complex Laves Mg-zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged *** addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 *** findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.

关键词： Quasicrystal Mg alloys Rapid solidification Scanning-transmission electron microscopy.

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Structural basis for polyuridine tract recognition by SARS-CoV-2 Nsp15

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Protein & Cell 2024年第7期15卷 547-552页

作者： Fumiaki Ito Hanjing Yang z.Hong zhou Xiaojiang S.Chen Molecular and Computational Biology Department of Biological SciencesUniversity of Southern CaliforniaLos AngelesCA 90089United States Department of Microbiology Immunology and Molecular GeneticsUniversity of CaliforniaLos AngelesCA 90095United States California NanoSystems Institute University of CaliforniaLos AngelesCA90095United States Genetic Molecular and Cellular Biology ProgramKeck School of MedicineUniversity of Southern CaliforniaLos AngelesCA 90089United States Norris Comprehensive Cancer Center University of Southern CaliforniaLos AngelesCA 90089United States Center of Excellence in NanoBiophysics University of Southern CaliforniaLos AngelesCA 90089United States

Dear Editor,Coronaviruses have evolved a wide array of tactics to evade host antiviral *** host cells detect invading foreign nucleic acids including viral genome and viral replication intermediates,they activate interferon(IFN)signaling via cytoplasmic pattern recognition receptors(Kang et al.,2002;Kato et al.,2006).Remarkable stealth activities exhibited by coronaviruses are facilitated by a series of non-structural proteins(Nsps),such as Nsp15(Deng and Baker,2018;Deng et al.,2019;Hackbart et al.,2020),which is a uridine-specific endoribonuclease that mediates evasion of host detection of viral double-stranded RNA(dsRNA)(Bhardwaj et al.,2004;Deng et al.,2017;Frazier et al.,2021;Ivanov et al.,2004).Nsp15 targets a polyuridine[poly(U)]tract on the coronavirus negative strand RNA(Hackbart et al.,2020).Nsp15 limits the abundance and length of poly(U)within the negative strand RNA 5ʹ-extension by trimming down the initially synthesized poly(U)lead sequence to the optimal length that can suppress dsRNA formation but still serves as a template for poly(A)tail of the positive strand genome of the coronaviruses(Hofmann and Brian,1991).

关键词： p15 interferon template

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Astragalus membranaceus (Fisch.) Bge. administered by dissolving microneedles achieves systemic therapeutic effects at low doses

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Journal of Traditional Chinese Medical Sciences 2024年第3期11卷 340-350页

作者： Chen Y. zhou z. zhang L. Ding z. Li P. Yan C. School of Life Sciences Beijing University of Chinese Medicine Beijing 102488 China Dongzhimen Hospital Beijing University of Chinese Medicine Beijing 100029 China School of Chinese Materia Medica Beijing University of Chinese Medicine Beijing 102488 China

Objective: To determine the main components of Astragalus membranaceus (Fisch.) Bge (A. membranaceus, Huang Qi), Astragaloside IV (AIV) and Astragalus polysaccharides (AP), to characterize their properties, evaluate their in vivo efficacy, and to analyze drug diffusion using dissolving microneedle (DMN) technology in vivo. Methods: Respectively, AIV- and AP-loaded DMNs comprising chitosan (CTS) and polyvinyl alcohol (PVA) were prepared via dual-mold forming. Their morphology, mechanical properties, in vivo solubility, and skin irritation characteristics were tested. In vivo efficacy was assessed in cyclophosphamide-induced immunosuppressed mice, in vivo diffusion of AIV and AP by DMNs and conventional methods was compared, and the rheological properties of AIV-CTS-PVA and AP-CTS-PVA mixtures were measured. Results: Subcutaneous dissolution and absorption of AIV-CTS-PVA and AP-CTS-PVA microneedles (MNs) at low doses (50%–17% of intraperitoneal AIV injection and 12%–4% of intravenous AP injection) reduced the spleen index and acid phosphatase activity in immunosuppressed mouse models, increased the thymus index, and achieved equivalent or better systemic therapeutic effects. Compared with injections, AIV and AP achieved controllable solid-liquid conversion through delivery with CTS-PVA MNs, resulting in highly localized aggregation within 48 h, reducing the initial explosive effect of the drug, and achieving stable and slow drug release. Conclusion: The present study enhances our understanding of the efficacy and remote effects of drug-loaded DMNs from a traditional Chinese medicine (TCM) perspective, thereby promoting the development of precise and efficient delivery of TCM and further expanding the drug-loading range and application scenarios for DMNs. © 2024 Beijing University of Chinese Medicine

关键词： Acupuncture Astragaloside IV Astragalus polysaccharides Dissolving microneedle Drug delivery Immunosuppression In vivo diffusion Rheological properties

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Solid-state Circuit Breaker Based on Cascaded Normally-on SiC JFETs for Medium-voltage DC Distribution Networks

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Protection and Control of Modern Power Systems 2024年第2期9卷 32-46页

作者： Dong He Haohui zhou zheng Lan wei wang Jinhui zeng Xueping Yu z.John Shen Chongqing University of Posts and Telecommunications ChongqingChina Henan Polytechnic University JiaozuoChina College of Electrical and Information Engineering Hunan University of TechnologyZhuzhou 412007China Hunan University ChangshaChina College of Electrical and Information Engineering Hunan UniversityChangshaChina College of Electrical Engineering Three Gorges University Rensselaer Polytechnic Institute TroyNYUSA

Solid-state circuit breakers(SSCBs)are critical components in the protection of medium-voltage DC distribution networks to facilitate arc-free,fast and reliable isolation of DC ***,limited by the capacity of a single semiconductor device,using semi-conductor-based SSCBs at high voltage is *** study presents the details of a 1.5 kV,63 A medi-um-voltage SSCB,composed primarily of a solid-state switch based on three cascaded normally-on silicon car-bide(SiC)junction field-effect transistors(JFETs)and a low-cost programmable gate drive *** and static voltage sharing among the cascaded SiC JFETs of the SSCB during fault isolation is realized using the pro-posed gate drive *** selection conditions for the key parameters of the SSCB gate driver are also ***,an improved pulse-width modulation cur-rent-limiting protection solution is proposed to identify the permanent overcurrent and transient inrush current associated with capacitive load startup in a DC distribu-tion *** the developed SSCB prototype and the fault test system,experimental results are obtained to validate the fault response performance of the *** Terms—Solid-state circuit breaker,DC distribu-tion network,SiC JFET,voltage balancing,inrush current.

关键词： Solid-state circuit breaker DC distribu-tion network SiC JFET voltage balancing inrush current

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Critical layer in liquid-solid system influencing the remediation of chromium using zeolite-supported sulfide nano zero-valent iron

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Journal of Environmental Sciences 2024年第1期135卷 232-241页

作者： Chundi zhou Caiyun Han Nengsheng Liu Faculty of Material and Environment Guangxi University for NationalitiesNanning 530008China College of Environmental Science and Engineering Tongji UniversityShanghai 200092China Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming 650093China

Sulfidated nano zero-valent iron particles were immobilized on zSM-5 zeolite(z/S-nzⅥ)and used for hexavalent chromium(Cr(Ⅵ))*** performance of z/S-nzⅥimproved with the increase in Cr(Ⅵ)concentration(while the performance significantly decreased for a Cr(Ⅵ)concentration of more than 60 mg/*** adsorption behavior for Cr(Ⅵ)was different from that reported in previous *** improved performance can be tailored for increasing efficiency of nano zero-valent iron(nzⅥ)corrosion,while the degree of corrosion of nzⅥwas affected by the concentration of the pollutant as discussed by kinetics,X-ray diffraction(XRD)and X-ray photoelectron spectrometer(XPS)*** experiments for the dissolution of ferrous ions and the dosage of adsorbent demonstrated that the critical layer in the liquid-solid system changed with the increase in the concentration of Cr(Ⅵ)(Cr(Ⅵ):z/S-nzⅥ>0.6).Moreover,the removal mechanisms of Cr(Ⅵ)were elucidated through XRD,transmission electron microscopy(TEM)and XPS *** results demonstrate that the species of chromium in the critical layer changed from Cr(Ⅲ)to Cr(Ⅵ)as the concentration of chromium increased from low to ***,the critical layer was composed of Cr(Ⅵ),Fe(Ⅱ),O and H ***,the experiments of coexisting ions and aging time confirmed that z/S-nzⅥpossessed high selectivity and stability to ensure efficiency and cost-effectiveness in practical applications.

关键词： Cr(VI) Corrosion Critical layer Selectivity Stability

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Programmable synthetic receptors:the next-generation of cell and gene therapies

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Signal Transduction and Targeted Therapy 2024年第2期9卷 376-400页

作者： Fei Teng Tongtong Cui Li zhou Qingqin Gao Qi zhou wei Li University of Chinese Academy of Sciences Beijing 101408China State Key Laboratory of Stem Cell and Regenerative Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Institute for Stem Cell and Regeneration Chinese Academy of SciencesBeijing 100101China Beijing Institute for Stem Cell and Regenerative Medicine Beijing 100101China

Cell and gene therapies hold tremendous promise for treating a range of difficult-to-treat ***,concerns over the safety and efficacy require to be further addressed in order to realize their full *** receptors,a synthetic biology tool that can precisely control the function of therapeutic cells and genetic modules,have been rapidly developed and applied as a powerful *** designed and engineered,they can be applied to finetune the therapeutic activities,i.e.,to regulate production of dosed,bioactive payloads by sensing and processing user-defined signals or *** review provides an overview of diverse synthetic receptor systems being used to reprogram therapeutic cells and their wide applications in biomedical *** a special focus on four synthetic receptor systems at the forefront,including chimeric antigen receptors(CARs)and synthetic Notch(synNotch)receptors,we address the generalized strategies to design,construct and improve synthetic ***,we also highlight the expanding landscape of therapeutic applications of the synthetic receptor systems as well as current challenges in their clinical translation.

关键词： synthetic landscape payload

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Neuroprotective effects of Shaoyao Gancao decoction against excitatory damage in PC12 cells based on the Src-NR2-nNOS pathway

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Journal of Traditional Chinese Medical Sciences 2024年第3期11卷 293-302页

作者： Fan X. Ma H. zhou T. Fu M. Qiao z. Feng Y. wang z. Shen Y. wang J. School of Traditional Chinese Medicine Beijing University of Chinese Medicine Beijing 102488 China These authors have contributed equally to this work. School of Traditional Chinese Medicine Xinjiang Medical University Urumqi 830017 China The Centre for Translational Biology Research Institute of McGill University Health Centre Montréal H4A 3J1 Canada

Objective: To explore the neuroprotective effects of the Shaoyao Gancao decoction (SGD) against excitatory damage in PC12 cells and the role of the Src-NR2-nNOS pathway mediation by SGD in regulating γ-aminobutyric acid (GABA)-glutamate (Glu) homeostasis. Methods: N-Methyl-D-aspartic acid (NMDA) was used to establish a PC12 cell excitability injury model. To investigate the neuroprotective effect of SGD, a cell counting kit-8 (CCK-8) assay was used to determine PC12 cell viability, Annexin V/Propidium Iodide (Annexin V/PI) double staining was used to determine PC12 cell apoptosis, and Ca2+ concentration was observed using laser confocal microscopy. GABA receptor agonists and antagonists were used to analyze the neuroprotective interactions between γ-aminobutyric acid (GABA) and NMDA receptors. Additionally, molecular biology techniques were used to determine mRNA and protein expression in the Src-NR2-nNOS pathway. we analyzed the correlations between the regulatory sites of GABA and NMDA interactions, excitatory neurotoxicity, and brain damage at the molecular level. Results: NMDA excitotoxic injury manifested as a significant decrease in cell activity, increased apoptosis and caspase-3 protein expression, and a significant increase in intracellular Ca2+ concentration. Administration of SGD, a GABAA receptor agonist (muscimol), or a GABAB receptor agonist (baclofen) decreased intracellular Ca2+ concentrations, attenuated apoptosis, and reversed NMDA-induced upregulation of caspase-3, Src, NMDAR2A, NMDAR2B, and nNOS. Unexpectedly, a GABAA receptor antagonist (bicuculline) and a GABAB receptor antagonist (saclofen) failed to significantly increase excitatory neurotoxicity. Conclusions: Taken together, these results not only provide an experimental basis for SGD administration in the clinical treatment of central nervous system injury diseases, but also suggest that the Src-NR2A-nNOS pathway may be a valuable target in excitotoxicity treatment. © 2024 Beijing Universit

关键词： N-Methyl-D-aspartic acid (NMDA) nNOS PC12 Shaoyao Gancao decoction Src γ-aminobutyric acid (GABA)

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Integrated interconnected porous and lamellar structures realized fast ion/electron conductivity in high-performance lithium-sulfur batteries

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Chinese Chemical Letters 2024年第6期35卷 161-167页

作者： Ya Song Mingxia zhou zhu Chen Huali Nie Jiao-Jing Shao Guangmin zhou School of Materials and Metallurgy Guizhou UniversityGuiyang 550025China Medical College of Guizhou University Guiyang 550025China College of Biological Science and Medical Engineering Donghua UniversityShanghai 201620China Shenzhen Geim Graphene Center Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China

The practical application of high-energy-density lithium-sulfur(Li-S)batteries have been highly praised for energy storage devices,while are largely hindered by the“shuttling effect”.Herein,core-shell carbon spheres composed of interlinked porous core and lamellar shell were designed to restrain the polysulfide *** microporous structure with pore size of around 1 nm effectively trap lithium ***,the interconnected porous core shortens the ion transfer distance and the lamellar carbon shell endows the carbon spheres with fast electron conduction,finally facilitating polysulfide conversion ***,the Li-S batteries with the carbon spheres as the interlayer show high discharge specific capacity of 1002 m Ah/g at 2 C with 574 m Ah/g remaining after 600 cycles,and high areal capacity of 5.48 m Ah/cm^(2) with sulfur loading of 4.67 mg/cm^(2) at 0.1 *** corresponding pouch cells also exhibit stable cycling stability with an initial discharge specific capacity of 1082 m Ah/g at 0.1 C.

关键词： Interlayer Shuttle effect Strong adsorption Porous carbon spheres Lithium-sulfur batteries

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Efficient photocatalytic NADH regeneration with Rh-loaded z-scheme mediator-free system

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Chinese Chemical Letters 2024年第2期35卷 496-500页

作者： Yi zhou Yiling He Ming Gao Ningkai Ding Juying Lei Yanbo zhou State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process East China University of Science and TechnologyShanghai 200237China National Engineering Research Center of Industrial wastewater Detoxication and Resource Recovery East China University of Science and TechnologyShanghai 200237China Shanghai Engineering Research Center for Multi-media Environmental Catalysis and Resource Utilization East China University of Science and TechnologyShanghai 200237China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Nicotinamide adenine dinucleotide(NADH)regeneration is necessary for the sustainable application of enzymatic *** Rh-based complex[Cp^(*)Rh(bpy)(H)]+has been widely used as an important mediator in NADH regeneration systems,but it is limited by complexity and high ***,a z-scheme was constructed by loading Rh onto carbon nitride nanosheets/carbon nitride quantum dots(CN-CNQD).The resultant catalyst achieved a high yield of NADH in a mediator-free(M-free)system of 0.283 mmol L^(−1) g^(−1) min^(−1),which is 5.29 times that of pure *** enzyme introduction experiments confirmed that the enzyme active product 1,4-NADH could reach 34.21%selectivity in the M-free *** research revealed that the heterojunction between CNs and CNQDs improved the NADH regeneration activity in the traditional M-involved system,while Rh loading was proved to optimize the yield and selectivity of 1,4-NADH in M-free *** immobilized Rh shows more competitiveness than[Cp^(*)Rh(bpy)(H)]^(+).This study contributes to the construction of an M-free system for further application in greener,lower-cost enzymatic processes.

关键词： Photocatalysis NADH regeneration Mediator-free Carbon nitride z-scheme

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