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Search Results: 1 - 10 of 22449 matches for " Bei-jing The National Orchid Conservation Center "
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The butterfly Pieris rapae resulting in the reproductive success of two transplanted orchids in a botanical garden

Hongfang Zhang,Liqiang Li,Zhongjian Liu,Yibo Luo,State Key Laboratory of Systematic,Evolutionary Botany,Institute of Botany,Chinese Academy of Sciences,Bei-jing The National Orchid Conservation Center,Shenzhen,Guangdong Graduate School of the Chinese Academy of Sciences,Beijing,

生物多样性 , 2010,
Abstract: Ex-situ conservation is an effective measure to prevent extinction of species.In order to learn the plant-pollinator relationship in ex situ habitat and shed insights into the ex situ conservation,we studied the pollination system and reproductive strategy of two orchids Ludisia discolor from Wutong Mountains,Shenzhen and Calanthe argenteo-striata from Malipo,Yunnan in the Botanical Garden of the National Orchid Conservation Center(NOCC),Shenzhen,southeastern China in 2007 and 2008.Both species have inflore...
Depolymerization of actin cytoskeleton is involved in stomatal closure-induced by extracellular calmodulin in Arabidopsis
XIAO Yumei CHEN Yuling,HUANG Rongfeng CHEN Jia WANG Xue-chen,
XIAO Yumei
,CHEN Yuling,HUANG Rongfeng,CHEN Jia & WANG Xue-chen . The National Key Laboratory of Plant Physiology and Biochemistry,College of Biological Sciences,China Agricultural University,Bei-jing,China,. College of Life Sciences,Hebei Normal University,Shijiazhuang,China,. Biotechnology Research Institute,Chinese Academy of Agricultural Sciences,Beijing,China

中国科学C辑(英文版) , 2004,
Abstract: Extracellular calmodulin (CaM) plays significant roles in many physiological proc-esses,but little is known about its mechanism of regulating stomatal movements. In this paper, whether CaM exists in the guard cell walls of Arabidopsis and whether depolymerization of actin cytoskeleton is involved in extracellular CaM-induced stomatal closing are investigated. It is found that CaM exists in guard cell walls of Arabidopsis, and its molecular weight is about 17 kD. Bioassay using CaM antagonists W7-agarose and anti-CaM serum shows that the endogenous extracellular CaM promotes stomatal closure and delays stomatal opening. The long radial actin filaments in guard cells undergo disruption in a time-dependent manner during exogenous CaM-induced stomatal closing. Pharmacological experiments show that depolymerization of ac-tin cytoskeleton enhances the effect of exogenous CaMinduced stomatal closing and polym-erization reduces the effect. We also find that exogenous CaM triggers an increase in Ca2+]cyt of guard cells. If Ca2+]cyt increase is blocked with EGTA, exogenous CaM-induced stomatal closure is inhibited. These results indicate that extracellular CaM causes elevation of Ca2+]cyt in guard cells, subsequently resulting in disruption of actin filaments and finally leading to guard cells closure.
Novel approach to synthesizing poly(propylene)-graft-poly(styrene) (PP-g-PS)
Li Ze,Zou Junfeng,LU Yingying,KE Yucai,ZHOU Nai,
,ZOU Junfeng,LU Yingying,KE Yucai,ZHOU Nai & HU Youliang . State Key Laboratory of Engineering Plastics,Center for Molecular Science,Institute of Chemistry,Chinese Academy of Sciences,Bei-jing,China,. Graduate Student of Chinese Academy of Sciences,Beijing,China Correspondence should be addressed to Hu Youliang

科学通报(英文版) , 2003,
Abstract: A novel synthetic route used for preparing PP-g-PS was designed. With this synthetic route, a series of graft copolymers with different contents of PS chain were synthesized successfully, and characterized by 13C-NMR, DSC, GPC.
Improved image registration based on second-order mutual information

CHEN Bei-jing,LI Jun-li,CHEN Gang,

计算机应用 , 2007,
Abstract: In this paper, we studied the influence of grey levels and neighborhood information on the technology of image registration based on second-order MI from some experiments, getting the best grey levels and neighborhood information to improve this technology. At last, we analyzed the effects of noise on second-order MI to explain the conclusions in our paper.
Bimodal PE prepared with combined iron (II) and nickel (II) olefin polymerization catalysts
WANG Shibo,LIU Dongbing,XU Renwei,MAO Bingquan,
WANG Shibo
,LIU Dongbing,XU Renwei,& MAO Bingquan . College of Science,Beijing University of Chemical Technology,Bei- jing,China,. Polyolefins National Engineering and Research Center,Beijing Re- search Institute of Chemical Industry,China Petroleum & Chemical Corporation,Beijing,China

科学通报(英文版) , 2006,
Abstract: Combined iron (II) and nickel (II) olefin polymerization catalysts could produce a kind of PE having the characters of ideal bimodal PE with ap- propriate conditions and catalysts. In the ethylene homopolymerization with triethylalkylaluminum (AlEt3) as the activator, the prepared bimodal PE contained not only branched PE of high molecular weight, but also linear PE of low molecular weight. And the amounts of both fractions were similar. Ideal bimodal PE resin was prepared in one polymerization reactor.
Roles for microtubule and microfilament cytoskeletons in animal cell cytokinesis
CHEN Zhongcai?,CAI Shang,JIANG Qing,ZHANG Chuanmao & TANG Xiaowei Institute of High Energy Physics,Chinese Academy of Sciences,Bei- jing,China,National Laboratory of Biomembrane,Membrane Biotechnology,

科学通报(英文版) , 2005,
Abstract: Microtubule and microfilament cytoskeletons play key roles in the whole process of cytokinesis. Although a number of hypotheses have been proposed to elucidate the mechanism of cytokinesis by microtubule and actin filament cytoskeletons, many reports are conflicting. In our study, combining the cytoskeletons drug treatments with the time-lapse video technology, we retested the key roles of microtubule and actin filament in cytokinesis. The results showed that depolymerization of microtubules by Nocoda- zole after the initiation of furrowing would not inhibit the furrow ingression, but obviously decrease the stiffness of daughter cells. Depolymerizing actin filaments by Cyto- chalasin B before metaphase would inhibit the initiation of furrowing but not chromosome segregation, resulting in the formation of binucleate cells; however, depolymerizing actin filaments during anaphase would prevent furrowing and lead to the regress of established furrow, also resulting in the formation of binucleate cells. Further, depolymerizing microtubules and actin filaments simultaneously after meta- phase would cause the quick regress of the furrow and the formation of binucleate cells. From these results we propose that a successful cytokinesis requires functions and coordina- tion of both the microtubule and actin filamentcytoskeletons. Microtubule cytoskeleton may function in the positioning and initiation of cleavage furrow, and the actin filament cy- toskeleton may play key roles in the initiation and ingression of the furrow.

CHENG Qi-sheng,CHU Wei,PAN Tong,MAO Xiu-min,NIU Hong-wei,GAO Jing-yu,ZHU Ying-jian Academe of Oil Production Technology of Jilin Oilfield Corporation,Songyuan,Qian An Oil Recovery Plant of Jilin Oilfield Corporation,National Engineering Research Center for Corrosion Control,

腐蚀科学与防护技术 , 2008,
Abstract: Serious scale formation was observed on a boiler in an oil recovery plant of Songyuan oilfield.The failure was then characterized by examinations with the corrosion products and scales formed.Thereafter several prevention measures were proposed.
Impacts of acid deposition On carbon sequestration and soil base cation retention in forests

BAI Xiaohui,ZHANG Jing,YANG Shengtian,LI Shunjiang,LI Wei,LI Qian,SHENG Haoran School of Geography,Beijing Normal University,Beijing Institute of Plant Nutrition,Natural Resources,Beijing Academy of Agriculture,Forestry Sciences,Beijing College of Environment,Beijing China National Environmental Monitoring Center,Beijing Linktech Navi Technology,Beijing,

环境科学学报 , 2010,
Abstract: A Forest Ecological Evaluation Model including four modules,i.e. Forest Soil Retaining Module,Forest Water Retaining Module,Forest Carbon Sequestration Module and Forest Soil Base Cation Retaining Module,was developed in this study based on the Soil Acidification Model and the Forest Productivity Model. Data of precipitation,soil and vegetation collected at Longli,Guizhou Province were used to evaluate the ecological effects of acid deposition on forests,such as carbon sequestration and soil base cation ret...
Species diversity of aquerrantia in the prawn pool and coast of Dongxiaomo

Jiao Xiaoyang National Marine Environmental Monitoring Center,Dalian,

生物多样性 , 1996,
Abstract: More than 94 species that belong to Bacillariophyta, Pyrrophyta, Cyanophyta, Chlorophyta, Chrysophyta, and Euglenophyceae etc., had ever existed in the aquerrantia of prawn pools and coast of Dongxiaomo in June to September,1991.Most of them which over 59 species are diatom, and among them 4 species have not been recorded in China before.There are some differences of the species diversity of aquerrantia between the prawn pool and coast.The range of Shannon Weaner species diversity index is from 0.12 to 3.17,the averange 1.52.
Hydrothermal diamond-anvil cell: application to studies of geologic fluids

I-Ming CHOU National Center,US Geological Survey,Reston,VA,USA,

岩石学报 , 2003,
Abstract: The hydrothermal diamond-anvil cell (HDAC) was designed to simulate the geologic conditions of crustal processes in the presence of water or other fluids. The HDAC has been used to apply external pressure to both synthetic and natural fluid inclusions in quartz to minimize problems caused by stretching or decrepitation of inclusions during microthermometric analysis. When the HDAC is loaded with a fluid sample, it can be considered as a large synthetic fluid inclusion and therefore, can be used to study the PVTX properties as well as phase relations of the sample fluid. Because the HDAC has a wide measurement pressure-temperature range and also allows in-situ optical observations, it has been used to study critical phenomena of various chemical systems, such as the geologically important hydrous silicate melts. It is possible, when the HDAC is combined with synchrotron X-ray sources, to obtain basic information on speciation and structure of metal including rare-earth elements (REE) complexes in hydrothermal solutions as revealed by X-ray absorption fine structure (XAFS) spectra. Recent modifications of the HDAC minimize the loss of intensity of X-rays due to scattering and absorption by the diamonds.These modifications are especially important for-studying elements with absorption edges below 10 keV and therefore particularly valuable for our understanding of transport and deposition of first-row transition elements and REE in hydrothermal environments.
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