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Properties and microstructure of copper–titanium alloys with magnesium additions

Rare Metals 2024年第5期43卷 2290-2299页

作者： Lue Huang li-jun Peng Jiang li Xu-jun Mi Gang Zhao Guo-Jie Huang Hao-Feng Xie Yi-Cheng Cao Wen-Jing Zhang Zhen Yang State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co. Ltd. GRIMAT Engineering Institute Co. Ltd. School of Materials Science and Engineering Northeastern University General Research Institute for Nonferrous Metals China Academy of Space Technology China Nonferrous Metals Mining Group (Tianjin) Co.Ltd

The volume fractions and morphology of precipitates in precipitation-strengthened Cu-Ti alloys,which precipitate mainly as continuous and discontinuous precipitates,are important for the application of the alloy.This study employed hardness and electrical conductivity tests transmission electron microscopy （TEM）,atom probe tomography （APT）,and first-principles calculations to demonstrate that the addition of Mg is effective for accelerating nanosized continuous β'-Cu4Ti precipitation as well as for suppressing the precipitation of coarse lamellar discontinuous β-Cu4Ti precipitates along the grain boundaries,resulting in Cu-Ti alloys with high yield strength and good electrical conductivity.The results showed that the continuous precipitation of β'-Cu4Ti was accelerated by the Mg additions,which reduced the supersaturation of the matrix,thereby reducing the chemical driving force for the discontinuous precipitates.On the other hand,Mg additions increased the mismatch between the discontinuous β-Cu4Ti precipitates and matrix decreased the nucleation rate of the discontinuous precipitates,and increased the spacing of the discontinuous precipitation layer,resulting in a lower growth rate of the discontinuous precipitates.Therefore,the addition of Mg to Cu-Ti alloys enhances the strength and improves the resistance to over-ageing.

关键词： Cu-Ti-Mg alloy Precipitation hardening Discontinuous precipitation Continuous precipitation Microstructure formation mechanism

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A Survey on an Emerging Safety Challenge for Autonomous Vehicles:Safety of the Intended Functionality

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Engineering 2024年第2期33卷 17-34页

作者： Hong Wang Wenbo Shao Chen Sun Kai Yang Dongpu Cao jun li Tsinghua Intelligent Vehicle Design and Safety Research Institute School of Vehicle and MobilityTsinghua UniversityBeijing 100084China CogDrive Lab Department of Mechanical and Mechatronics EngineeringUniversity of WaterlooWaterlooON N2L3G1Canada College of Mechanical and Vehicle Engineering Chongqing UniversityChongqing 400044China

As the complexity of autonomous vehicles(AVs)continues to increase and artificial intelligence algorithms are becoming increasingly ubiquitous,a novel safety concern known as the safety of the intended functionality(SOTIF)has emerged,presenting significant challenges to the widespread deployment of AVs.SOTIF focuses on issues arising from the functional insufficiencies of the AVs’intended functionality or its implementation,apart from conventional safety considerations.From the systems engineering standpoint,this study offers a comprehensive exploration of the SOTIF landscape by reviewing academic research,practical activities,challenges,and perspectives across the development,verification,validation,and operation phases.Academic research encompasses system-level SOTIF studies and algorithm-related SOTIF issues and solutions.Moreover,it encapsulates practical SOTIF activities undertaken by corporations,government entities,and academic institutions spanning international and Chinese contexts,focusing on the overarching methodologies and practices in different phases.Finally,the paper presents future challenges and outlook pertaining to the development,verification,validation,and operation phases,motivating stakeholders to address the remaining obstacles and challenges.

关键词： Safety of the intended functionality Autonomous vehicles Artificial intelligence Uncertainty Verification Validation

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Cycloastragenol induces apoptosis and protective autophagy through AMPK/ULK1/mTOR axis in human non-small cell lung cancer cell lines

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Journal of Integrative Medicine 2024年第4期22卷 503-514页

作者： li-hua Zhu Yu-pei liang lian Yang Feng Zhu li-jun Jia He-gen lia Department of Oncology Longhua Hospital Shanghai University of Traditional Chinese Medicine Cancer Institute of Traditional Chinese Medicine Longhua Hospital Shanghai University of Traditional Chinese Medicine Department of Laboratory Medicine Huadong Hospital Fudan University

Objective:Studies have demonstrated that cycloastragenol induces antitumor effects in prostate, colorectal and gastric cancers; however, its efficacy for inhibiting the proliferation of lung cancer cells is largely unexplored. This study explores the efficacy of cycloastragenol for inhibiting non-small cell lung cancer(NSCLC) and elucidates the underlying molecular mechanisms.Methods:The effects of cycloastragenol on lung cancer cell proliferation were assessed using an adenosine triphosphate monitoring system based on firefly luciferase and clonogenic formation assays.Cycloastragenol-induced apoptosis in lung cancer cells was evaluated using dual staining flow cytometry with an annexin V-fluorescein isothiocyanate/propidium iodide kit. To elucidate the role of cycloastragenol in the induction of apoptosis, apoptosis-related proteins were examined using Western blots.Immunofluorescence and Western blotting were used to determine whether cycloastragenol could induce autophagy in lung cancer cells. Genetic techniques, including small interfering RNA technology,were used to investigate the underlying mechanisms. The effects against lung cancer and biosafety of cycloastragenol were evaluated using a mouse subcutaneous tumor model.Results:Cycloastragenol triggered both autophagy and apoptosis. Specifically, cycloastragenol promoted apoptosis by facilitating the accumulation of phorbol-12-myristate-13-acetate-induced protein 1(NOXA), a critical apoptosis-related protein. Moreover, cycloastragenol induced a protective autophagy response through modulation of the adenosine 5?-monophosphate-activated protein kinase (AMPK)/unc-51-like autophagy-activating kinase (ULK1)/mammalian target of rapamycin (mTOR) pathway.Conclusion:Our study sheds new light on the antitumor efficacy and mechanism of action of cycloastragenol in NSCLC. This insight provides a scientific basis for exploring combination therapies that use cycloastragenol and inhibiting the AMPK/ULK1/mTOR pathway as a promising approach to combating lung cancer.

关键词： Non-small cell lung cancer Cycloastragenol Autophagy Apoptosis

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Hydrogen storage thermodynamics and kinetics of as-cast Ce-Mg-Ni-based alloy

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Journal of Iron and Steel Research(International) 2024年第3期31卷 752-766页

作者： Yan Qi Xin Zhang jun li Dong-liang Zhao Shi-hai Guo Yang-huan Zhang Department of Functional Material Research Central Iron and Steel Research InstituteBeijing 100081China China Rare Earth New Material(Weishan)Co..Ltd. Jining 277600ShandongChina Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina

The reaction kinetics of alloys based on magnesium are known to be greatly improved by the partial substitution of Mg with rare earths and transition metals,particularly Ni.The enhanced superficial hydrogen dissociation rate,the weakened Mg-H bond and the lower activation energy following element replacement are thought to be related to the better performance.The experimental alloys Ce5Mg_(95-x)Ni_(x)(x=5,10,15)were smelted by the vacuum induction melting.The phase transformation and structural evolution of experimental alloys before and after reaction with hydrogen were char-acterized by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.The cast specimens contain CeMg_(12),Mg and Mg_(2)Ni phases,and the increase in Ni content results in an obvious growth of Mg_(2)Ni phase.The isothermal and non-isothermal hydrogenation and dehydrogenation kinetics of the experimental specimens were investi-gated using the Sievert apparatus,differential scanning calorimetry and thermal gravimetric analyzer.The activation energy may be calculated using the Arrhenius and Kissinger equations.The experimental alloys have been shown to have good activation properties,with a reversible hydriding and dehydriding capacities of around 5.0 wt.%in the first cycle.The initial dehydrogenation temperature of MgH_(2) decreases from 557.5 to 537.7 K with changing Ni content from 5 to 15 at.%.The dehydrogenation activation energy also reduces from 77.09 to 62.96 kJ/mol,which explains the improved hydrogen storage performance caused by Ni substitution.It can be shown that the impact of Ni on the decomposition enthalpy of MgH_(2) is quite modest,with the absolute enthalpy(ΔHr)only decreasing from 78.48 to 76.15 kJ/mol.

关键词： Mg-based alloy Ni content Hydrogen storage kinetics Thermodynamic property Activation energy

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BMSC-derived Exosomes Ameliorate Peritoneal Dialysis-associated Peritoneal Fibrosis via the Mir-27a-3p/TP53 Pathway

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Current Medical Science 2024年第2期44卷 333-345页

作者： jun-li ZHAO lin ZHAO Qiu-nan ZHAN Miao liU Ting ZHANG Wen-wen CHU Department of Nephrology Shanghai University of Medicine&Health Sciences Ailiated Zhoupu HospitalShanghai 201318China Orthopedic Department Guangming Traditional Chinese Medicine Hospital of Pudong New AreaShanghai 201399China

Objective:Peritoneal fibrosis(PF)is the main cause of declining efficiency and ultrafiltration failure of the peritoneum,which restricts the long-term application of peritoneal dialysis(PD).This study aimed to investigate the therapeutic effects and mechanisms of bone marrow mesenchymal stem cells-derived exosomes(BMSC-Exos)on PF in response to PD.Methods:Small RNA sequencing analysis of BMSC-Exos was performed by second-generation sequencing.C57BL/6J mice were infused with 4.25%glucose-based peritoneal dialysis fluid(PDF)for 6 consecutive weeks to establish a PF model.A total of 36 mice were randomly divided into 6 groups:control group,1.5%PDF group,2.5%PDF group,4.25%PDF group,BMSC-Exos treatment group,and BMSC-Exos+TP53 treatment group.Reverse transcription quantitative polymerase chain reaction(RT-qPCR)was performed to measure the expression level of miR-27a-3p in BMSC-Exos and peritoneum of mice treated with different concentrations of PDF.HE and Masson staining were performed to evaluate the extent of PF.The therapeutic potential of BMSC-Exos for PF was examined through pathological examination,RT-qPCR,Western blotting,and peritoneal function analyses.Epithelial-mesenchymal transition(EMT)of HMrSV5 was induced with 4.25%PDF.Cells were divided into control group,4.25%PDF group,BMSC-Exos treatment group,and BMSC-Exos+TP53 treatment group.Cell Counting Kit-8 assay was used to measure cell viability,and transwell migration assay was used to verify the capacity of BMSC-Exos to inhibit EMT in HMrSV5 cells.Results:Small RNA sequencing analysis showed that miR-27a-3p was highly expressed in BMSC-derived exosomes compared to BMSCs.The RT-qPCR results showed that the expression of miR-27a-3p was upregulated in BMSC-Exos,but decreased in PD mice.We found that PF was glucose concentration-dependently enhanced in the peritoneum of the PD mice.Compared with the control mice,the PD mice showed high solute transport and decreased ultrafiltration volume as well as an obvious fibroproliferative response,with markedly increas

关键词： peritoneal fibrosis bone marrow mesenchymal stem cell-derived exosomes miR-27a-3p TP53 epithelialmesenchymal transition

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A MOF/poly(thioctic acid)composite for enhanced gold extraction from water matrices

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Nano Research 2024年第1期17卷 382-389页

作者： Ruiqing li Sen Yan Tianwei Xue Rongxing Qiu Yin li Wenli Hao Guangkuo Xu Yanliang Wang Yanzhen Hong Yuzhong Su Hongtao Wang Shuliang Yang li Peng jun li College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China College of Energy Xiamen UniversityXiamen 361005China National Engineering Laboratory for Green Chemical Productions of Alcohols Ethers and EstersXiamen UniversityXiamen 361005China Collaborative Innovation Center of Chemistry for Energy Materials Xiamen UniversityXiamen 361005China

With the fast generation of electronic waste(e-waste)and the increasing depletion of metal resources,“urban mining”that can selectively recover gold from secondary resources has attracted great interest.Construction of materials with high extraction capacity and satisfying selectivity in complex aqueous-based matrices still remains challenging.Here,a novel metal-organic framework/polymer composite(Fe-BTC/poly(thioctic acid),denoted as Fe-BTC/pTA)has been newly synthesized and applied for selective gold recovery in different matrices(river water,seawater,and leaching solution of e-waste).Benefiting from the high specific surface area and suitable pore sizes as well as the rational design of active sites,the composite exhibits high adsorption capacity(920 mg/g),high removal efficiency(>99%),fast kinetics(below 0.1 ppb within 10 min),and good applicability in complex matrices,which are better than those of most reported sulfur-containing adsorbents.Solid-state metallic gold with high purity can be effectively enriched due to the high recyclability and long-term stability of the composite.The material after adsorption can be further applied as a heterogeneous catalyst for water remediation due to the in situ generated gold nanoparticles by the redox reaction between Au(III)ions and the S-containing groups in the composites.

关键词： metal-organic frameworks(MOFs) poly(thioctic acid)(pTA) polymer composites gold recovery urban mining

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A New Heat Transfer Model for Multi-Gradient Drilling with Hollow Sphere Injection

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Fluid Dynamics & Materials Processing 2024年第3期20卷 537-546页

作者： Jiangshuai Wang Chuchu Cai Pan Fu jun li Hongwei Yang Song Deng School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhouChina CNPC Research Institute of Engineering Technology Co. Ltd.BeijingChina National Engineering Research Center for Oil&Gas Drilling and Completion Technology BeijingChina College of Petroleum Engineering China University of Petroleum(Beijing)BeijingChina College of Petroleum Karamay CampusChina University of Petroleum(Beijing)BeijingChina

Multi-gradient drilling is a new offshore drilling method.The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure.In this study,a new heat transfer model is proposed by which the variable mass flow is properly taken into account.Using this model,the effects of the main factors influencing the wellbore temperature are analyzed.The results indicate that at the position where the separation injection device is installed,the temperature increase of the fluid in the drill pipe is mitigated due to the inflow/outflow of hollow spheres,and the temperature drop of the fluid in the annulus also decreases.In addition,a lower separation efficiency of the device,a shallower installation depth and a smaller circulating displacement tend to increase the temperature near the bottom of the annulus,thereby helping to reduce the hydrate generation area and playing a positive role in the prevention and control of hydrates in deepwater drilling.

关键词： Multi-gradient drilling wellbore temperature hydrate separate injection device variable mass

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Time-history performance optimization of flapping wing motion using a deep learning based prediction model

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Chinese Journal of Aeronautics 2024年第5期37卷 317-331页

作者： Tianqi WANG liu liU jun li lifang ZENG School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027China Huanjiang Laboratory Zhuji 311800China

Flapping Wing Micro Aerial Vehicles(FWMAVs)have caused great concern in various fields because of their high efficiency and maneuverability.Flapping wing motion is a very important factor that affects the performance of the aircraft,and previous works have always focused on the time-averaged performance optimization.However,the time-history performance is equally important in the design of motion mechanism and flight control system.In this paper,a time-history performance optimization framework based on deep learning and multi-island genetic algorithm is presented,which is designed in order to obtain the optimal two-dimensional flapping wing motion.Firstly,the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics method.The aerodynamic surrogate model for flapping wing is obtained after the convergence of training.The surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift,thrust and moment.Secondly,the optimization framework is used to optimize the flapping wing motion in two specific cases,in which the optimized propulsive efficiencies have been improved by over 40%compared with the baselines.Thirdly,a dimensionless parameter C_(variation)is proposed to describe the variation of the time-history characteristics,and it is found that C_(variation)of lift varies significantly even under close time-averaged performances.Considering the importance of time-history performance in practical applications,the optimization that integrates the propulsion efficiency as well as C_(variation)is carried out.The final optimal flapping wing motion balances good time-averaged and time-history performance.

关键词： FWMAV Flapping wing motion Deep learning Unsteady aerodynamic performance Optimization Time-history curve

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Biological scaffold as potential platforms for stem cells:Current development and applications in wound healing

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World Journal of Stem Cells 2024年第4期16卷 334-352页

作者： Jie-Yu Xiang lin Kang Zi-Ming li Song-Lu Tseng li-Quan Wang Tian-Hao li Zhu-jun li Jiu-Zuo Huang Nan-Ze Yu Xiao Long Department of Plastic and Reconstructive Surgery Peking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China Biomedical Engineering Facility Institute of Clinical MedicinePeking Union Medical College HospitalChinese Academy of Medical SciencesBeijing 100021China

Wound repair is a complex challenge for both clinical practitioners and researchers.Conventional approaches for wound repair have several limitations.Stem cell-based therapy has emerged as a novel strategy to address this issue,exhibiting significant potential for enhancing wound healing rates,improving wound quality,and promoting skin regeneration.However,the use of stem cells in skin regeneration presents several challenges.Recently,stem cells and biomaterials have been identified as crucial components of the wound-healing process.Combination therapy involving the development of biocompatible scaffolds,accompanying cells,multiple biological factors,and structures resembling the natural extracellular matrix(ECM)has gained considerable attention.Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells,providing them with an environment conducive to growth,similar to that of the ECM.These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing.This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing,emphasizing their capacity to facilitate stem cell adhesion,proliferation,differentiation,and paracrine functions.Additionally,we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

关键词： Stem-cell-based therapy Biological scaffolds Wound healing Extracellular matrix mimicry Cellular activities enhancement Scaffold characteristics

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Meiotic transcriptional reprogramming mediated by cell-cell communications in humans and mice revealed by scATACseq and scRNA-seq

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Zoological Research 2024年第3期45卷 601-616页

作者： Hai-Quan Wang Xiao-Long Wu Jing Zhang Si-Ting Wang Yong-Juan Sang Kang li Chao-Fan Yang Fei Sun Chao-jun li State Key Laboratory of Reproductive Medicine and Offspring Health Center for Global HealthSchool of Public HealthNanjing Medical UniversityNanjingJiangsu 211166China Medical School Nanjing UniversityNanjingJiangsu 210093China Zhejiang University School of Medicine HangzhouZhejiang 310016China Department of Urology and Andrology Sir Run Run Shaw HospitalZhejiang University School of MedicineHangzhouZhejiang 310000China Model Animal Research Center of Medical School Nanjing UniversityNanjingNanjingJiangsu 210093China liangzhu Laboratory Zhejiang UniversityHangzhouZhejiang 311121China

Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,we performed single-cell ATAC-seq of human testis tissues and observed reprogramming during the transition from zygotene to pachytene spermatocytes.This event,conserved in mice,involved the deactivation of genes associated with meiosis after reprogramming and the activation of those related to spermatogenesis before their functional onset.Furthermore,we identified 282 transcriptional regulators(TRs)that underwent activation or deactivation subsequent to this process.Evidence suggested that physical contact signals from Sertoli cells may regulate these TRs in spermatocytes,while secreted ENHO signals may alter metabolic patterns in these cells.Our results further indicated that defective transcriptional reprogramming may be associated with non-obstructive azoospermia(NOA).This study revealed the importance of both physical contact and secreted signals between Sertoli cells and germ cells in meiotic progression.

关键词： Single-cell RNA-seq Single-cell ATAC-seq Spermatogenesis Meiosis Transcriptional reprogramming Cell-cell communication

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