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Mechanoresponse of stem cells for vascular repair

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World Journal of Stem Cells 2019年第12期11卷 1104-1114页

作者： ge-Er tian Jun-Teng Zhou Xiao-Jing Liu yong-Can Huang Regenerative Medicine Research Center of West China Hospital Sichuan UniversityChengdu 610041Sichuan ProvinceChina Department of Cardiology of West China Hospital Sichuan UniversityChengdu 610041Sichuan ProvinceChina Shenzhen Engineering Laboratory of Orthopaedic Regenerative Technologies National and Local Joint Engineering Research Center of Orthopaedic BiomaterialsPeking University Shenzhen HospitalShenzhen 518036Guangdong ProvinceChina

Stem cells have shown great potential in vascular *** evidence indicates that mechanical forces such as shear stress and cyclic strain can regulate the adhesion,proliferation,migration,and differentiation of stem cells via serious signaling *** enrichment and differentiation of stem cells play an important role in the angiogenesis and maintenance of vascular *** normal tissues,blood flow directly affects the microenvironment of vascular endothelial cells(ECs);in pathological status,the abnormal interactions between blood flow and vessels contribute to the injury of ***,the altered mechanical forces are transduced into cells by mechanosensors to trigger the reformation of *** process occurs when signaling pathways related to EC differentiation are ***,a deep understanding of the responses of stem cells to mechanical stresses and the underlying mechanisms involved in this process is essential for clinical *** this the review,we provide an overview of the role of stem cells in vascular repair,outline the performance of stem cells under the mechanical stress stimulation,and describe the related signaling pathways.

关键词： Stem cells Shear stress Strain stress Vascular repair

Response of nitrogen mineralization dynamics and biochemical properties to litter amendments to soils of a poplar plantation

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Journal of Forestry Research 2018年第4期29卷 913-922页

作者： Xiaomin ge Shiping Deng Ling Zhu yong Li Zhiyuan Jia Ye tian Luozhong Tang Department of Silviculture College of Forestry Nanjing Forestry University Nanjing Jiangsu 210037 People's Republic of China Department of Plant and Soil Sciences Oklahoma State University Stillwater OK 74078 USA Co-Innovation Center for Sustainable Forestry in Southern China Nanjing Jiangsu 210037 People's Republic of China

Understanding the impact of plant litters on soil nitrogen （N） dynamics could facilitate development of management strategies that promote plantation ecosystem function. Our objective was to evaluate the effects of different litter types on N mineralization and availability, microbial biomass, and activities of L-asparaginase and odiphenol oxidase （o-DPO） in soils of a poplar （Populus deltoides） plantation through 24 weeks of incubation experiments. The tested litters included foliage （F）, branch （B）, or root （R） of poplar trees, and understory vegetation （U） or a mixture of F, B, and U （M）. Litter amendments led to rapid N immobilization during the first 4 weeks of incubation, while net N mineralization was detected in all tested soils from 6 to 24 weeks of incubation, with zero-order reaction rate constants （k） ranging from 7.7 to 9.6 mg N released kg-1 soil wk-1. Moreover, litter addition led to increased （C） 49-128% and increased microbial biomass carbon MBC：MBN ratio by 5-92%, strengthened activities of L-aspaxaginase and o-DPO by 14-74%; Up to about 37 kg N ha-1 net increase in mineralized N in litter added soils during 24 weeks of incubation suggests that adequate poplar and understory litter management could lead to reduced inputs while facilitate sustainable and economic viable plantation production.

关键词： Plant litter Nitrogen mineralization Soilmicrobial biomass L-asparaginase o-diphenol oxidase

A mixed-cation lead iodide MA_(1-x)EA_xPbI_3 absorber for perovskite solar cells

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Journal of Energy Chemistry 2018年第1期27卷 215-218页

作者： yong Wang Taiyang Zhang ge Li Feng Xu tian Wang Yihui Li Yang Yang Yixin Zhao School of Environmental Science and Engineering Shanghai Jiao Tong University Clean Energy Research Institute China Huaneng Group

The mixed-cation lead halide perovskites have emerged as a new class of promising light harvesting materials for solar cells. The formamidinium（FA）, methylammonium（MA） and Cs cations are widely studied in the field of mixed-cation perovskites. Here, we have investigated ethylammonium（EA） as an alternative cation to fabricate a mixed-cation perovskite of MA_（1-x）EA_xPbI_3. We have characterized the materials using the X-ray diffraction（XRD）, scanning electron microscope（SEM）, and UV–vis spectrum. Our results have confirmed the successful incorporation of EA cations into MAPbI_3. Interestingly, the optimal amount of EA to achieve the best performance is quite low. This is different from the FA–MA mixed-cation perovskites although EA and FA have similar radii. In short, the EA–MA mixed-cation perovskite has some material and device properties highly distinguishable from the FA–MA one.

关键词： Mixed cation Ethylammonium MA1-xEAxPbl3 Perovskite solar cell

Effect of mechanical force on domain switching in BiFeO3 ultrathin films

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Science China(Physics,Mechanics & Astronomy) 2020年第1期63卷 93-99页

作者： ShiLu tian Can Wang yong Zhou Yu Feng XiaoKang Yao Chen ge Meng He GuoZhen Yang KuiJuan Jin Institute of Physics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

Ferroelectric polarization can be switched by an external applied electric field and may also be reversed by a mechanical force via flexoelectricity from the strain *** this study,we report the mechanical writing of an epitaxial BiFeO3(BFO)thin film and the combined action of an applied mechanical force and electric field on domain switching,where the mechanical force and electric field are applied using the tip of atomic force *** the applied force exceeds the threshold value,the upward polarization of the BFO thin film can be reversed by pure mechanical force via flexoelectricity;when an electric field is simultaneously applied,the mechanical force can reduce the coercive electric field because both the piezoelectricity from the homogeneous strain and the flexoelectricity from strain gradient contribute to the internal electric field in the *** mechanically switched domains exhibit a slightly lower surface potential when compared with that exhibited by the electrically switched domains due to no charge injection in the mechanical ***,both the mechanically and electrically switched domains exhibit a tunneling electroresistance in the BFO ferroelectric tunnel junction.

关键词： BFO flexoelectricity mechanical writing ferroelectric domain reversal

Optimized operation plan for sewer sediment control

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 335-341页

作者： yong-chao ZHOU tian LI Institute of Municipal Engineering Zhejiang University Hangzhou 310058 China College of Environmental Science and Engineering Tongji University Shanghai 200096 China

Severe operational problems of sediment deposition have frequently occurred in stormwater sewer systems in Shanghai city due to the flat topography of the area and serious illicit connections. To control sewer sediment and its subsequential problems,optimized operation plans were proposed and an innovative performance assessment method was developed. Simula-tion results demonstrated that,through changing the way of pump operation and installing necessary actuators in the system,the optimized operations,especially batch intermittent intercept plan,effectively improved the flow velocity in the entire system in dry-weather condition. In conclusion,the optimized operation is an innovative idea for improving the performance and solving the problem of sediment deposition in the sewer system in Shanghai,China.

关键词： Sewer system Sediment control Performance assessment Simulation

The hardest transition metal nitride predicted from machine learning

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Science Bulletin 2018年第15期63卷 947-948页

作者： yong, jun tian Center for High Pressure Science. State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qiahuangdaa 066004 China

Materials that possess Vickers hardness(Hv)higher than 40 GPa are known as superhard materials,which have important applications in industry and scientific ***,there are only two types of superhard materials,*** and cubic boron nitride(c-BN),which are widely used as cutting,polishing,drilling and coating *** diamond has unrivaled hardness of 60–120 GPa,its applications in some circumstances,such as cutting ferrous materials,are limited due to poor

关键词：金属氮化物机器学习涂层材料预言科学研究

Variable scale-convex-peak method for weak signal detection

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Science China(Technological Sciences) 2021年第2期64卷 331-340页

作者： tian RuiLan ZHAO ZhiJie XU yong State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Applied Mathematics Northwestern Polytechnical UniversityXi’an 710072China

Avariable scale-convex-peak method is constructed to identify the frequency of weak harmonic signal. The key of this method is to find a set of optimal identification coefficients to make the transition of dynamic behavior topologically persistent. By the stochastic Melnikov method, the lower bound of the chaotic threshold continuous function is obtained in the mean-square *** intermediate value theorem is applied to detect the optimal identification coefficients. For the designated identification system, there is a valuable co-frequency-convex-peak in bifurcation diagram, which indicates the state transition of chaosperiod-chaos. With the change of the weak signal amplitude and external noise intensity in a certain range, the convex peak phenomenon is still maintained, which leads to the identification of frequency. Furthermore, the proposition of the existence of reversible scaling transformation is introduced to detect the frequency of the harmonic signal in engineering. The feasibility of constructing the hardware and software platforms of the variable scale-convex-peak method is verified by the experimental results of circuit design and the results of early fault diagnosis of actual bearings, respectively.

关键词： variable-scale Duffing system stochastic Melnikov method scale transformation circuit experiment fault diagnosis

Sensitivity of Influential Factors on Needle Insertion Experiments:A Quantitative Analysis on Phantom Deformations and Needle Deflections

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Chinese Journal of Mechanical Engineering 2020年第6期33卷 38-48页

作者： Murong Li yong Lei tian Xu State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou310027China

High repeatability of needle insertion experiments is essential to the needle-phantom interaction model ***,the influential factors governing the accuracy of the phantom and needle deformations have not been systematically *** this paper,the impact of influential factors,including phantom characteristic represented by the ratio of DMSO and thawing time(TT),needle properties represented by needle external diameter(NED)and operating factors such as needle insertion velocity(IV),insertion positions(IP)and repeated insertion times(RITs)are analyzed by orthogonal experiment *** range calculation shows the most sensitive parameters to phantom deformations are RITs,IV and DMSO while the most sensitive parameters to needle deflection are DMSO,TT and *** variance analysis,the significant factors on maximum tissue deformation(MTD)are IV,followed by RITs,DMSO and *** NED and TT have nearly no significant impact on *** significant sequence on maximum needle deflection(MND)is as follows:DMSO,TT and *** show that,among all impacting factors,phantom deformation is susceptible to both material properties and operative factors while the needle deflection is more susceptible to material properties of the phantom,which can help researchers in related fields to conduct experiments in a more precise manner and better understand the needle-phantom interaction mechanism.

关键词： Needle insertion Sensitivity analysis Tissue deformation Needle deflection

Effects of Warm Deformation on Mechanical Properties of TRIP Aided Fe-C-Mn-Si Multiphase Steel

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Journal of Iron and Steel Research International 2012年第6期19卷 47-52页

作者： tian yong LI Zhuan~ State Key Laboratory of Roiling and Automation Northeastern University Shenyang 110004 LiaoningChina Department o{ Material Engineering Shenyang Institute of Aeronautical Engineering Shenyang110034 Liaoning China）

Warm deformation tests were performed using a kind of tubby heater. The microstructures and mechanical properties of an Fe-C-Mn-Si multiphase steel resulting from different warm deformation temperatures were investiga- ted by using LOM （light optical microscopy）, SEM and XRD. The results indicated that the microstructure contai- ning polygonal ferrite, granular bainite and a significant amount of the stable retained austenite can be obtained through hot deformation and subsequent austempering. Warm deformation temperature affects the mechanical prop- erties of the hot rolled TRIP steels. Ultimate tensile strength balance reached maximum （881 MPa） when the speci- men was deformed at 250 ~C, and the total elongation and strength-ductility reached maximum （38% and 28 614 MPa ~ ~, respectively） at deforming temperature of 100 ~C. Martensite could nucleate when austenite was deformed above M~, because mechanical driving force compensates the decrease of chemical driving force. The TRIP effect occurs in the Fe-C-Mn-Si multiphase steel at deforming temperature ranging from 15 to 350 ~C. The results of the effects of warm deformation on the mechanical properties of the Fe-C-Mn-Si multiphase steel can provide theoretical basis for the ap- plications and the warm working of the hot rolled TRIP sheet steels in industrial manufacturing.

关键词： warm deformation Fe-C-Mn-Si multiphase steel TRIP effect mechanical property