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Plant community dynamics during the growing season of typical ecosystems on the Tibetan Plateau

Geography and Sustainability 2020年第4期1卷 266-274页

作者： Xiaoxia Chen Yuqiang Tian Yong Zhang Yu Cui Yan Zhao Weijian Sun Center for Human-Environment System Sustainability(CHESS) State Key Laboratory of Earth Surface Processes and Resource EcologyBeijing Normal UniversityBeijing 100875China school of Natural Resources Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Institute of Grassland Research Chinese Academy of Agricultural SciencesHohhot 010010China

The relationships between vegetation and environmental factors have always been a core concern of *** dynamic characteristics of plant communities during the growing season can directly reflect these relation-ships,so we examined this issue for three typical ecosystems on the Tibetan *** the growing season,the dominant species remained stable while non-dominant species changed significantly in the alpine meadow and alpine steppe and a mono-dominant community was found in the temperate desert *** to the seasonal variations of temperature and soil water content,plant species diversity varied significantly during the growing *** richness,Pielou evenness and Simpson diversity indices differed significantly in the alpine meadow and alpine *** total biomass of these three ecosystems was the largest during the middle growing *** was greater in the alpine meadow than the alpine steeps or temperature *** root-to-shoot ratio was the lowest during the middle growing season for the alpine meadow and alpine steppe and largest during the early growing season for temperate desert *** showed the belowground and total biomass were greatly affected by soil physicochemical *** linear stepwise regression showed the above ground biomass was greatly affected by relative atmospheric humidity and belowground and total biomass were greatly affected by soil organic carbon,total nitrogen at 0-20 cm soil depth and pH at 10-20 cm soil *** findings pro-vide insights into understanding the relationships between vegetation and environmental factors and promote the sustainable utilization of local grasslands on the Tibetan Plateau.

关键词： Community dynamics Species diversity Root-to-shoot ratio Growing season Tibetan Plateau Grasslands

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Toxoplasma gondii adhesion and apoptosis of chicken erythrocytes

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Animal Diseases 2023年第3期3卷 178-187页

作者： Chenghuan Li Xiaohan Zhang Xiaoyu Sang Yanhong He Saeed El-Ashram Yingying Ding Tiantian Jiang Na Yang Key Laboratory of Livestock Infectious Diseases in Northeast China Ministry of EducationKey Laboratory of ZoonosisCollege of Animal Science and Veterinary MedicineShenyang Agricultural UniversityShenyangChina Faculty of Science Kafrelsheikh UniversityKafr El-SheikhEgypt Department of Pediatrics School of MedicineUniversity of CaliforniaLa JollaSan DiegoCAUSA

Toxoplasma gondi is thought to infect all nucleated cells in warm-blooded animals,including poultry,mammals,and ***,it is unclear whether *** can infect chicken erythrocytes due to the nucleated nature of these *** to the special role of chicken erythrocytes in innate immunity,we investigated the cell-cell interaction between *** and erythrocytes to elucidate the role of chicken erythrocytes in *** *** apoptosis was analyzed by transwell assay and flow *** immunofluorescence method was used to examine the reorganization of vimentin during *** infection in both Vero cells and chicken *** reorganization of actin was evaluated to further examine the invasion capacity of tachyzoites on chicken erythrocytes during *** discovered that *** can adhere to but not invade chicken erythrocytes and eventually cause apoptosis in chicken *** tachyzoites were cocultured with chicken erythrocytes in vitro,the transcrip-tional levels of *** MIC3,ROP16,and ROP18 were significantly *** addition,the rearrangement of host cell vimentin,a type Il cytoskeleton protein regulated by *** infection,was not ***,the parasite-induced ring-shaped actin structure was not formed in the host-parasite ***(RH strain)tachyzoites pref-erentially invaded Vero cells and replicated in chicken blood monocytes,but they were not found in chicken *** findings showed that although *** could attach to the surface of chicken erythrocytes,but couldn't invade ***,we found that the *** secretome,lysates,and intact tachyzoites could cause apoptosis of chicken erythrocytes,which suggested a complex mechanism involved in the apoptosis of chicken erythrocytes induced by *** study elucidated that *** could not infect nucleated chicken erythrocytes and enriched our understanding of the transmission mechanism of *** am

关键词： Toxoplasma gondi Chicken erythrocytes Invasion Apoptosis

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The importance of the bite angle of metal(Ⅲ) salen catalysts in the sequestration of CO_(2) with epoxides in mild conditions

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Green Chemical Engineering 2022年第2期3卷 180-187页

作者： Anna Vidal-Lopez Sergio Posada-Perez Miquel Sola Valerio D'Elia Albert Poater Institut de Quimica Computacional i Catalisi and Departament de Quimica Universitat de GironaC/Maria Aurelia Capmany6917003GironaCataloniaSpain Department of Chemistry Universitat Autonoma de BarcelonaCerdanyola del VallesCatalonia08193Spain Department of Materials Science and Engineering School of Molecular Science and EngineeringVidyasirimedhi Institute of Science and Technology(VISTEC)21210PayupnaiWang ChanThailand

Located in the middle of the fever to solve the problem of CO_(2)emissions in the environment,CO_(2)sequestration by reaction with epoxides is one of the key tools,as it not only fixes CO_(2),but also makes it functional by leading to cyclic ***,the results are focused specifically on the formation of cyclic organic carbonates catalyzed by metal-salen complexes,previously achieved with yttrium and scandium,that are compared with those of analogous complexes containing metals from the first transition series,such as cobalt or *** functional theory(DFT)calculations allow to determine whether this switch of metals will be feasible and provide the basis for instigating future experimental efforts in this *** calculations analyzing the structure and electronics of the catalysts allow us to give not only a clear picture of whether these catalysts will be efficient,but also allow us to assess which metal center is the most convenient and/or whether the catalytic reaction will occur under mild *** buried volume calculations with the SambVca packages shed light on the different catalytic pockets of monometallic first row transition metals *** III salen *** predictive catalysis results show that the bite O-M-O angle plays an essential role in the catalysis.

关键词： CO_(2)fixation Salen catalyst CO_(2)functionalization Cyclic carbonate DFT calculations Predictive catalysis

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Complementary fruiting phenologies facilitate sharing of one pollinator fig wasp by two fig trees

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Journal of Plant Ecology 2015年第2期8卷 197-206页

作者： Gui-Xiang Liu Da-Rong Yang Yan-Qiong Peng Stephen G.Compton Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of Sciences88 Xuefu RoadKunming 650223China University of Chinese Academy of Science 19 Yuquan roadBeijing 100049China school of Biology University of LeedsWoodhouse LaneLeeds LS29JTUK Department of Zoology and Entomology Rhodes UniversityLower University RoadGrahamstown 6140South Africa

Aims most pollinator fig wasps are host plant specific,with each spe-cies only breeding in the figs of one fig tree species,but increasing numbers of species are known to be pollinated by more than one fig wasp,and in rare instances host switching can result in Ficus species sharing *** this study,we examined factors facilitating observed host switching at Xishuangbanna in southwestern(sW)China,where Ficus squamosa is at the northern edge of its range and lacks the fig wasps that pollinate it elsewhere,and its figs are colonized by a Ceratosolen pollinator that routinely breeds in figs of *** We recorded the habitat preferences of *** and ***-yla at Xishuangbanna,and compared characteristics such as fig size,location and colour at receptive ***,the vegetative and reproductive phenologies in the populations of *** and *** were recorded weekly at Xishuangbanna Tropical botanical garden for 1 *** Findings Ficus squamosa is a shrub found near fast-flowing rivers,*** is a small tree of disturbed forest *** preferring different habitats,they can be found growing close *** species have figs located at or near ground level,but they differ in size when *** production in *** was concentrated in the colder *** produced more figs in summer but had some through-out the *** absence of its normal pollinators,in combination with similarly located figs and partially complementary fruiting patterns appear to have facilitated colonization of *** by the routine pollinator of *** figs probably also share similar attractant *** host switching suggests one mechanism whereby fig trees can acquire new pollinators and emphasizes the likely significance of edges of ranges in the genesis of novel fig tree-fig wasp relationships.

关键词： agaonidae edge of range Ficus host specificity host switching

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Transplantation of neural stem cells overexpressing glial cell line-derived neurotrophic factor enhances Akt and Erkl/2 signaling and neurogenesis in rats after stroke

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Chinese Medical Journal 2013年第7期126卷 1302-1309页

作者： YUAN Miao WEN Sheng-jun YANG Chao-xian PANG Yuan-guang GAO Xiao-qing LIU Xiao-qing HUANG Liang YUAN Qiong-lan Department of Anatomy and Neurobiology Tong3i University School of Medicine Shanghai 200092 China State Key Laboratory of Medical Neurobiology Fudan University Shanghai 200433 China Department of Neurobiology Luzhou Medical College Luzhou Sichuan 646000 China

Background Our previous studies have indicated that the beneficial effects of grafting neural stem cells （NSCs） overexpressing glial cell line-derived neurotrophic factor （GDNF） in rats after stroke. However, the underlying mechanisms are highly debatable. In this study, we investigated whether neurogenesis, Akt, and extracellular signal- regulated kinase 1/2 （Erkl/2） signaling were involved in this process. Methods Transient ischemic stroke were induced by occluding middle cerebral artery for 2 hours and reperfusion. At 3 days after reperfusion, GDNF/NSCs, NSCs, and vehicle were administered. Immunohistochemical staining was used to evaluate neurogenesis by nestin antibody; phosphorylation of Akt and Erkl/2 was investigated by Western blotting analysis. Results Transplantation of GDNF/NSCs and NSCs significantly increased nestin-positive cells compared to control group （vehicle） from 1 to 7 weeks after reperfusion, and GDNF/NSCs showed stronger effect than NSCs at 2 and 3 weeks after reperfusion. Meanwhile, enhanced phosphorylation level of Erkl/2 was observed in the GDNF/NSCs and NSCs groups compared with control group, and phosphorylation level of Erkl/2 in GDNF/NSCs group was remarkably higher than that of NSCs group at any given time. In contrast, expression of mitogen-activated protein kinase phosphatase-1 （MKP-1）, known as inhibitor of Erkl/2 signaling, was significantly decreased in the GDNF/NSCs and NSCs groups compared with the control group. Moreover, much enhanced and prolonged phosphorylation level of Akt of GDNF/NSCs group was detected compared with control and NSCs group. Conclusion Grafting GDNF/NSCs enhances neurogenesis and activates Akt and Erkl/2 signaling, that may provide the potential for GDNF/NSCs in stroke treatment.

关键词： glial cell line-derived neurotrophic factor neural stem cells transplantation neurogenesis 4kt and Erkl/2 signaling

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Cenozoic Stratigraphy Deformation History in the Central and Eastern of Qaidam Basin by the Balance Section Restoration and its Implication

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Acta Geologica Sinica(English Edition) 2009年第2期83卷 359-371页

作者： LIU Dongliang FANG Xiaomin GAO Junping WANG Yadong ZHANG Weilin MIAO Yunfa LIU Yongqian ZHANG Yuezhong Center of Basin Resources and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Graduate school Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Western China＇s Environmental Systems Ministry of Education of China College of Resources and Environment Lanzhou University Lanzhou 730000 China Research Institute of Petroleum Exploration and Development PetroChina Qinghai Oilfield Company Dunhuang Gansu 736202 China

The Qaidam Basin, located in the northern margin of the Qinghai-Tibet Plateau, is a large Mesozoic-Cenozoic basin, and bears huge thick Cenozoic strata. The geologic events of the Indian- Eurasian plate-plate collision since -55 Ma have been well recorded. Based on the latest progress in high-resolution stratigraphy, a technique of balanced section was applied to six pieces of northeast- southwest geologic seismic profiles in the central and eastern of the Qaidam Basin to reconstruct the crustal shortening deformation history during the Cenozoic collision. The results show that the Qaidam Basin began to shorten deformation nearly synchronous to the early collision, manifesting as a weak compression, the deformation increased significantly during the middle and Late Eocene, and then weakened slightly and began to accelerate rapidly since the Late Miocene, especially since the Quaternary, reflecting this powerful compressional deformation and rapid uplift of the northern Tibetan Plateau around the Qaidam Basin.

关键词： balance section shortening deformation history Qaidam Basin uplift of the TibetanPlateau

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Dynamic Characteristics of Long -Span Steel -Concrete CompositeBeam Bridge Based on Vehicle -Bridge Coupling Effect

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吉首大学学报（自然科学版） 2024年第5期45卷 45-51页

作者： WANG Jianxing CAI Ran JIA Yumeng ZHANG Jianmeng school of Civil Engineering North China University of TechnologyBeijing 100144China

In order to investigate the effect of vehicle-bridge coupling on the dynamic characteristics of the bridge,a steel-concrete composite beam suspension bridge is taken as the research object,and a three-dimensional spatial model of the bridge and a biaxial vehicle model of the vehicle are established,and then a vehicle-bridge coupling vibration system is constructed on the basis of the Nemak-βmethod,and the impact coefficients of each part of the bridge are obtained under different bridge deck unevenness and vehicle *** simulation results show that the bridge deck unevenness has the greatest influence on the vibration response of the bridge,and the bridge impact coefficient increases along with the increase in the level of bridge deck unevenness,and the impact coefficient of the main longitudinal girder and the secondary longitudinal girder achieves the maximum value when the level 4 unevenness is 0.328 and 0.314,respectively;when the vehicle speed is increased,the vibration response of the bridge increases and then decreases,and the impact coefficient of the bridge in the middle of the bridge at a speed of 60 km/h achieves the maximum value of 0.192.

关键词： highway bridge vehicle-bridge coupling effect steel-concrete composite beam suspension bridge dynamic characteristics

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Infrared microthermometry of fluid inclusion in sphalerite:A case study of the Xinqiao deposit in the middle-Lower Yangtze metallogenic belt

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中国科学技术大学学报 2024年第5期54卷 10-21,I0006页

作者： Yangyang Wang Yilin Xiao State Key Laboratory of Lithospheric and Environmental Coevolution School of Earth and Space SciencesUniversity of Science of Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Infrared microthermometry allows direct measurement of fluid inclusions hosted in opaque ore minerals and can provide direct constraints on the evolution of ore-forming *** study presents infrared microthermometry of spherite-hosted fluid inclusions from the Xinqiao deposit in the middle-Lower Yangtze Metallogenic Belt and sheds new light on the ore genesis of the *** that infrared light may lead to non-negligible temperature deviations during microthermometry,some tests were first conducted to ensure the accuracy of the microthermometric *** measurement results indicated that using the lowest light intensity of the microscope and inserting an optical filter were effective in minimizing the possible temperature deviations of infrared *** sphalerite-hosted fluid inclusions from the Xinqiao deposit were *** show homogenization temperature ranging from~200 to 350℃,but have two separate salinity groups(1.0 wt%-10 wt%and 15.1 wt%-19.2 wt%NaCl equivalent).The low-salinity group represents sedimentary exhalative(SEDEX)-associated fluids,whereas the high-salinity group results from modification by later magmatic hydrothermal *** with published fluid inclusion data,the four-stage fluid evolution of the Xinqiao deposit was ***,our data suggest that the Xinqiao deposit was formed by twostage metallogenic events including SEDEX and magmatic-hydrothermal mineralization.

关键词： infrared microthermometry fluid inclusion sphalerite Xinqiao deposit

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Influences of environmental changes on water storage variations in Central Asia

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Journal of Geographical Sciences 2018年第7期28卷 985-1000页

作者：胡伟杰刘海隆包安明 Attia M.EL-TANTAWI State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and Geography CAS CAS Research Center for Ecology and Environment of Central Asia school of Resources and Environment University of Electronic Science and Technology of China Institute of African Research and Studies Cairo University

The spatio-temporal pattern of the global water resource has significantly changed with climate change and intensified human activities. The regional economy and ecological environment are highly affected by terrestrial water storage(TWS), especially in arid areas. To investigate the response relationships between TWS and changing environments(climate change and human activities) in Central Asia, we used the Gravity Recovery and Climate Experiment(GRACE) data, Climatic Research Unit(CRU) climate data and Moderate Resolution Imaging Spectroradiometer(MODIS) remote sensing data products(MOD16A2, MOD13A3 and MCD12Q1) from 2003 to 2013, as well as the slope and Pearson correlation analysis methods. Results indicate that:(1) TWS in about 77% of the study area decreased from 2003 to 2013. The total change volume of TWS is about 2915.6 × 108 m^3. The areas of decreased TWS are mainly distributed in the middle of Central Asia, while the areas of increased TWS are concentrated in the middle-altitude regions of the Kazakhstan hills and Tarim Basin.(2) TWS in about 5.91% of areas, mainly distributed in the mountain and piedmont zones, is significantly positively correlated with precipitation, while only 3.78% of areas show significant correlation between TWS and temperature. If the response time was delayed by three months, there would be a very good correlation between temperature and TWS.(3) There is a significantly positive relationship between TWS and Normalized Difference Vegetation Index(NDVI) in 13.35% of the study area.(4) The area of significantly positive correlation between TWS and evapotranspiration is about 31.87%, mainly situated in mountainous areas and northwestern Kazakhstan. The reduction of regional TWS is related to precipitation more than evaporation. Increasing farmland area may explain why some areas show increasing precipitation and decreasing evapotranspiration.(5) The influences of land use on TWS are still not very clear. This study could provide sci

关键词： terrestrial water storage Central Asia climate change land use

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Chemical weathering intensity and element migration features of the Xiashu loess profile in Zhenjiang, Jiangsu Province

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Journal of Geographical Sciences 2008年第3期18卷 341-352页

作者： CHEN Yingyong LI Xusheng HAN Zhiyong YANG Shouye WANG Yongbo YANG Dayuan school of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment CAS Xi＇an 710075 China State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China

The chemical weathering intensity and element migration features of the Xiashu loess profile in Zhenjiang are studied in this paper.（1）The Xiashu loess profile underwent moderate chemical *** seems that the precipitation is a more important factor than the temperature in controlling the process of the chemical weathering.（2）The major elements such as Si,K,Na,Ca,Mg,Mn and P were migrated and leached,while the elements Fe and Ti were slightly *** migration features of the major elements reveal that the Xiashu loess finished the primary process of chemical weathering characterized by leaching of Ca and Na,and almost reached the secondary process characterized by leaching of *** the elements Sr and Ga,other trace elements such as Th,Ba,Cu,Zn,Co,Ni,Cr and V were *** might be caused by both the biogeochemical process and the adsorption of trace elements by clay mineral and organic materials.（3）The difference of element migration down the Xiashu loess profile reveals that the climate was warm and wet at the early-middle stage of the middle *** the end of the middle Pleistocene,it became dry and *** the early stage of the Late Pleistocene,the paleoclimate became warm and wet *** a whole,the paleoclimate generally became drier and cooler in this region from the beginning of the middle Pleistocene.

关键词： Xiashu loess chemical weathering element migration Zhenjiang

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