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A regime-switching stochastic SIR epidemic model with a saturated incidence and limited medical resources

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International Journal of Biomathematics 2023年第7期16卷 91-110页

作者： Wei Wei Wei Xu jiankang liu Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 ShaanciP.R.China

The stochastic switching SIR epidemic model with saturated incidence and limited medical treatment is investigated in this *** using Lyapunov methods and Ito formula,we first prove that the system has a unique global positive solution with any positive initial *** combining inequality technique and the ergodic property of Markov switching,the suficient conditions for extinction and persistence in the mean of the disease are *** results demonstrate that increasing medical resources and improving supply efficiency can accelerate the transition from the persistent state to the extinct ***,the high incidence rate will slow down the extinction of the ***,the switching noise can induce the system to toggle between the extinct and persistent ***,some numerical simulations are carried out to confirm the analytical results.

关键词： Epidemic model extinction persistence Markov switching saturated incidence

围封对荒漠草原典型植物群落特征及多样性的影响

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水土保持研究 2025年第1期32卷 121-130+140页

作者：王益涛刘建康武志嘉张博华兰慧琴黄祥祥宁夏大学生态环境学院西北退化生态系统恢复与重建教育部重点实验室西北土地退化与生态恢复国家重点实验室培育基地宁夏大学林业与草业学院

[目的]揭示围封对荒漠草原典型植物群落特征及多样性的影响，可为宁夏荒漠草原植物资源保护、生物多样性保育、草地资源可持续利用与管理提供科学依据。[方法]以宁夏荒漠草原分布广泛的猪毛蒿(Artemisia scoparia)、短花针茅(Stipa brev... 详细信息

[目的]揭示围封对荒漠草原典型植物群落特征及多样性的影响，可为宁夏荒漠草原植物资源保护、生物多样性保育、草地资源可持续利用与管理提供科学依据。[方法]以宁夏荒漠草原分布广泛的猪毛蒿(Artemisia scoparia)、短花针茅(Stipa breviflora)、苦豆子(Sophora alopecuroides)和油蒿(Artemisia ordosica)4种典型植物群落为研究对象，研究围封措施对不同植物群落结构和功能特征的影响。[结果]围封不会改变4种植物群落中建群种优势地位，但改变了其功能群物种组成及重要值；围封增加了一年生植物(猪毛蒿)群落内物种总数(增幅为13.33%),但降低了多年生植物(短花针茅、苦豆子、油蒿)群落内物种总数(降幅分别为30%,34.78%和40%),降低了4种植物群落中多年生杂类草物种数量，并增加了多年生植物群落中多年生杂草和多年生禾草的重要值；围封增加了4种植物群落的高度和地上生物量，并增加了猪毛蒿、短花针茅和油蒿群落的盖度，降低了4种植物群落的Margalef丰富度指数，多年生草本植物(短花针茅、苦豆子)群落的Shannon-Wiener和Simpson指数，但增加了一年生植物群落的Shannon-Wiener, Simpson和Pielou指数；从群落建群种生活型角度分析，α多样性整体表现为多年生草本>半灌木>一年生草本植物群落；地上生物量与盖度、高度呈极显著正相关关系(p<0.001),与Margalef丰富度指数呈极显著负相关关系(p<0.001),与Shannon-Wiener指数呈显著负相关关系(p<0.05)。[结论]围封可通过改变不同植物群落物种组成对群落的盖度、高度及地上生物量产生积极影响，但不同植物群落的多样性特征对围封措施的敏感性存在差异。

关键词：围封荒漠草原典型群落群落特征地上生物量

Biomaterial Scaffolds with Biomimetic Fluidic Channels for Hepatocyte Culture

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Journal of Bionic Engineering 2013年第1期10卷 57-64页

作者： Xiao Li jiankang He Yaxiong liu Qian Zhao WanquanWu Dichen Li Zhongmin Jin State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Xi'an 710054 P. R. China

Biomaterial scaffolds play an important role in maintaining the viability and biological functions of highly metabolic hepatocytes in liver tissue engineering. One of the major challenges involves building a complex microchannel network inside three-dimensional （3D） scaffolds for efficient mass transportation. Here we presented a biomimetic strategy to generate a mi- crochannel network within porous biomaterial scaffolds by mimicking the vascular tree of rat liver. The typical parameters of the blood vessels were incorporated into the biomimetic design of the microchannel network such as branching angle and diameter. Silk fibroin-gelatin scaffolds with biomimetic vascular tree were fabricated by combining micromolding, freeze drying and 3D rolling techniques. The relationship between the micro-channeled design and flow pattern was revealed by a flow experiment, which indicated that the scaffolds with biomimetic vascular tree exhibited unique capability in improving mass transportation inside the 3D scaffold. The 3D scaffolds, preseeded with primary hepatocytes, were dynamically cultured in a bioreactor system. The results confirmed that the pre-designed biomimetic microchannel network facilitated the generation and expansion of hepatocytes.

关键词： liver tissue engineering scaffold biomimetic vascular tree dynamic culture hepatocyte

Effect of Hole Density and Confining Pressure on Mechanical Behavior of Porous Specimens:An Insight from Discrete Element Modeling

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Computer Modeling in Engineering & Sciences 2020年第10期125卷 259-280页

作者： Yuanchao Zhang Zhiyuan Xia Yujing Jiang Miao Chen jiankang liu Qian Yin Nagasaki University Nagasaki852-8521Japan University of Science and Technology Beijing Beijing100083China Shandong University of Science and Technology Qingdao266590China China University of Mining and Technology Xuzhou221116China

Hole-like defects are very common in natural rock or coal mass,and play an important role in the failure and mechanical behaviors of rock or coal *** this research,multi-holed coal specimens are constructed numerically and calibrated based on UDEC-GBM ***,the strength,deformation and failure behavior of the porous specimens are analyzed,with consideration of hole density(P)and confining pressure(σ_(3)).The simulation results are highly consistent with those available experiment results,and show that the compressive strength decreases exponentially with the increasing hole *** strength loss is mainly caused by the reduction of cohesion when PP_(cr).Also,the increasing hole density linearly reduces the tangent and secant modulus and causes greater nonlinear deformation of multi-holed ***,the failure patterns,coalescence mechanism and damage behavior of the multi-holed specimens are revealed based on the analysis of mesoscopic displacement fields and stress distribution around *** research promotes a better understanding of the effects of hole density and confining pressure on the failure and mechanical behavior of porous geomaterials.

关键词： Porous specimen failure strength DEM

Seasonal variation and longitudinal distribution of copepods in the main river area of the Three Gorges Reservoir

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Frontiers in Biology 2008年第4期3卷 525-529页

作者： Jianliang YAO Junzeng XUE Dengyuan WANG Qinghua CAI Xiangfei HUANG jiankang liu Agronomy College Xinjiang Agriculture UniversityUrumqi 830052China College of Aquatic-life Sciences and Technology Shanghai Fisheries UniversityShanghai 200090China State Key Laboratory of Freshwater Ecology and Biotechnology Wuhan 430072China

The ecosystem of the Three Gorges in the Yangtze River was changed into an artificial lake(reservoir)ecosystem after impoundment in June *** surveyed the seasonal variation and spatial distribution of copepods from April 2004 to January 2005 in order to provide data for clarifying the successional pattern of the *** Jiangjin to Maoping,eight copepod species were collected and classified into Calanoida(2),Harpacticoida(1),and Cyclopoida(5).Among them,Mesocyclops pehpeiensis,*** and Sinocalanus dorrii had a relatively wide *** distinct difference in species number was found among the sampling sites,but the species composition was *** composition,distribution and density of copepods showed significant seasonal *** addition,copepod density showed an obvious gradient with the distance from the reservoir dam:the nearer to the dam,the denser the copepods.

关键词： copepod zooplankton community ecology Three Gorges Reservoir Yangtze River

Sexual differences of the effects of prenatal stress on the expression of extracellular signal-regulated kinaseas in the hippocampus of offspring rats

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Neural Regeneration Research 2006年第1期1卷 14-17页

作者： Qing Cai Zhongliang Zhu Xiaoli Fan Ning Jia Qinghong Li Liang Song Hui Li jiankang liu Department of Physiology and Pathophysiology School of Medicine Key laboratory of Environment and Gene Related to Diseases Ministry of Education. Xi＇an Jiaotong University Xi＇an 710061 Shaanxi Province China College of Life Science Northwest University Xi＇an 710069 Shaanxi Province China Shaanxi Nature Museum Xi＇an 710061. ShaanxiProvince China Department of Pediatrics First Affiliated Hospital Xi＇an Jiaotong University Xi＇an 710061 Shaanxi Province China Institute for Nutritional Sciences Chinese Academy of Sciences Shanghai 200031 China Department of Molecular and Cell Biology University of California Berkeley CA 94720

BACKGROUND： Prenatal stress has been shown to inhibit cell proliferation in the dentate gyrus and hippocampus, reduce hippocampal volume, and cause neuronal loss and oxidative damage in the hippocampus of offspring rats, but the sexual difference of the effects on offsprings is seldom referred to. OBJECTIVE： To observe the effect of prenatal stress to adult pregnant rats on expression of extracellular signal-regulated kinases （ERK） in hippocampus of the offspring rats of different genders. DESIGN ： A randomized and control animal experiment.SETTING： Department of Physiology and Pathophysiology, School of Medicine, Xi＇an Jiaotong University. MATERIALS ： The experiments were carried out in the Key Laboratory of Environment and Gene Related Diseases （Xi＇an Jiaotong University）, Ministry of Education between October 2005 and March 2006. Fifteen female and five male adult Sprague-Dawley rats were adopted. Female rats weighing 230-250 g and male rats weighing 280-350 g were used. METHODS： The virgin female rats were placed overnight with adult male rats （3：1） for mating. A total of twelve pregnant rats were randomly assigned to prenatal stress group （PNS group, n=6） and control group （n=6）. The pregnant rats of the PNS group were exposed to restraint stress on days 14-20 of pregnancy three times a day, 45 minutes for each time . The restraint device was a transparent plastic tube （6.8 cm in diameter） with air holes for breathing and closed end. The length could be adjusted to accommodate the size of the animals. To prevent habituation of animals to the daily procedure, restraint periods were randomly shifted within certain time periods （8：00-11：00, 11：00-14：00, and 16：00-19：00）. After birth, offsprings of all groups were culled to 8-10 litters in each group and housed in the same animal room, and kept together with their biologic mothers. The pregnant rats of the control group were left undisturbed. On day 21, after all the offspring were weaned, male and female

关键词： Sexual differences of the effects of prenatal stress on the expression of extracellular signal-regulated kinaseas in the hippocampus of offspring rats

Intelligent Building Load Scheduling Based on Multi-Objective Multi-Verse Algorithm

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Energy and Power Engineering 2021年第4期13卷 19-29页

作者： Jiangyong liu jiankang liu Lv Fan Lingzhi Yi Huina Song Qingna Zeng College of Information Engineering & Hunan Province Engineering Research Center for Multi-Energy Collaborative Control Technology Xiangtan University Xiangtan China Willfar Information Technologies Co. Ltd. Changsha China Lianhu Town Central Health Center Chongqing China

In the multi-objective of intelligent building load scheduling, aiming at the problem of how to select Pareto frontier scheme for multi-objective optimization algorithm, the current optimal scheme mechanism combined with multi-objective multi-verse algorithm is used to optimize the intelligent building load scheduling. The update mechanism is changed in updating the position of the universe, and the process of correction coding is omitted in the iterative process of the algorithm, which reduces the com-putational complexity. The feasibility and effectiveness of the proposed method are verified by the optimal scheduling experiments of residential loads.

关键词： Intelligent Building Load Scheduling Multi-Objective Optimization Multi-Objective Multi-Verse Algorithm

Exercise promotes angiogenesis by enhancing endothelial cell fatty acid utilization via liver-derived extracellular vesicle miR-122-5p

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Journal of Sport and Health Science 2022年第4期11卷 495-508页

作者： Jing Lou Jie Wu Mengya Feng Xue Dang Guiling Wu Hongyan Yang Yan Wang Jia Li Yong Zhao Changhong Shi jiankang liu Lin Zhao Xing Zhang Feng Gao Center for Mitochondrial Biology and Medicine The Key Laboratory of Biomedical Information Engineering of Ministry of EducationSchool of Life Science and TechnologyXi’an Jiaotong UniversityXi’an 710049China School of Aerospace Medicine Fourth Military Medical UniversityXi’an 710032China Medical School of Chinese PLA Beijing 100853China Laboratory Animal Center Fourth Military Medical UniversityXi’an 710032China

Background:Angiogenesis constitutes a major mechanism responsible for exercise-induced beneficial *** previous study identified a cluster of differentially expressed extracellular vesicle microRNAs(miRNAs)after exercise and found that some of them act as ***,whether these extracellular vesicle miRNAs mediate the exercise-induced angiogenesis remains ***:A 9-day treadmill training was used as an exercise model in C57BL/6 ***-specific adeno-associated virus 8 was used to knock down microRNA-122-5p(miR-122-5p).Human umbilical vein endothelial cells were used in ***:Among these differentially expressed extracellular vesicle miRNAs,miR-122-5p was identified as a potent pro-angiogenic factor that activated vascular endothelial growth factor signaling and promoted angiogenesis both in vivo and in *** increased circulating levels of miR-122-5p,which was produced mainly by the liver and shuttled by extracellular vesicles in *** of circulating miR-122-5p or liver-specific knockdown of miR-122-5p significantly abolished the exercise-induced pro-angiogenic effect in skeletal muscles,and exerciseimproved muscle performance in ***,miR-122-5p promoted angiogenesis through shifting substrate preference to fatty acids in endothelial cells,and miR-122-5p upregulated endothelial cell fatty-acid utilization by targeting 1-acyl-sn-glycerol-3-phosphate acyltransferase(AGPAT1).In addition,miR-122-5p increased capillary density in perilesional skin tissues and accelerated wound healing in ***:These findings demonstrated that exercise promotes angiogenesis through upregulation of liver-derived extracellular vesicle miR-122-5p,which enhances fatty acid utilization by targeting AGPAT1 in endothelial cells,highlighting the therapeutic potential of miR-122-5p in tissue repair.

关键词： Angiogenesis Endothelial cells Exerkine Extracellular vesicle Metabolic shift

产前应激对发育海马神经元及其超微结构的影响

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中国病理生理杂志 2003年第12期19卷 1614-1617页

作者：陈尉娜朱忠良赵妍李霞 jiankang liu 西安交通大学医学院生理教研室陕西西安710061 Department of Molecular＆Cell Biology University of California Berkeley CA. USA

目的 :观察产前应激 (PS)对子鼠海马神经元和神经元超微结构是否有损伤作用 ,以及这种损伤是否与氧化物的过度生成有关。方法 :采用束缚应激模型 ,观察出生后 1个月雄性子鼠的海马神经元数量、神经元超微结构及神经型一氧化氮合酶 (nNOS... 详细信息

目的 :观察产前应激 (PS)对子鼠海马神经元和神经元超微结构是否有损伤作用 ,以及这种损伤是否与氧化物的过度生成有关。方法 :采用束缚应激模型 ,观察出生后 1个月雄性子鼠的海马神经元数量、神经元超微结构及神经型一氧化氮合酶 (nNOS)表达的变化。结果 :晚期应激 (LS)引起子鼠海马CA1和CA4区的细胞数量明显减少 ;电镜可见PS使子鼠海马CA1区神经元超微结构发生改变 ,表现为线粒体肿大、边界不清、电子密度不均 ,脂褐素增多 ,偶见核变形 ;中期应激 (MS)使子鼠海马CA1、CA2、CA3区和DG内nNOS阳性表达量显著升高 ,LS使子鼠海马CA1、CA2、CA3、CA4区和DG内nNOS阳性表达量也显著升高。结论 :结果提示 ,PS对子鼠海马神经元及神经元超微结构有损伤作用 ,这种损伤可能由氧化物过度生成引起。

关键词：应激海马氧化物大鼠