191 resultados para SHANGHAI


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BACKGROUND: Hypoxia and ischemia induce neuronal damage, decreased neuronal numbers and synaptophysin levels, and deficits in learning and memory functions. Previous studies have shown that lycium barbarum polysaccharide, the most effective component of barbary wolfberry fruit, has protective effects on neural cells in hypoxia-ischemia. OBJECTIVE: To investigate the effects of Naotan Pill on glutamate-treated neural cells and on cognitive function in juvenile rats following hypoxia-ischemia. DESIGN, TIME AND SETTING: The randomized, controlled, in vivo study was performed at the Cell Laboratory of Lanzhou University, Lanzhou Institute of Modern Physics of Chinese Academy of Sciences, and Department of Traditional Chinese Medicine of Gansu Provincial Rehabilitation Center Hospital, China from December 2005 to August 2006. The cellular neurobiology, in vitro experiment was conducted at the Institute of Human Anatomy, Histology, Embryology and Neuroscience, School of Basic Medical Sciences, Lanzhou University, and Department of Traditional Chinese Medicine of Gansu Provincial Rehabilitation Center Hospital, China from March 2007 to January 2008. MATERIALS: Naotan Pill, composed of barbary wolfberry fruit, danshen root, grassleaf sweetflag rhizome, and glossy privet fruit, was prepared by Gansu Provincial Rehabilitation Center, China. Rabbit anti-synaptophysin, choline acetyl transferase polyclonal antibody, streptavidin-biotin complex kit and diaminobenzidine kit (Boster, Wuhan, China), as well as glutamate (Hualian, Shanghai, China) were used in this study. METHODS: Cortical neural cells were isolated from neonatal Wistar rats. Neural cell damage models were induced using glutamate, and administered Naotan Pill prior to and following damage. A total of 54 juvenile Wistar rats were equally and randomly assigned into model, Naotan Pill, and sham operation groups. The left common carotid artery was ligated, and then rat models of hypoxic-ischemic injury were assigned to the model and Naotan Pill groups. At 2 days following model induction, rats in the Naotan Pill group were administered Naotan Pill suspension for 21 days. In the model and sham operation groups, rats received an equal volume of saline. MAIN OUTCOME MEASURES: Neural cell morphology was observed using an inverted phase contrast microscope. Survival rate of neural cells was measured by MTT assay. Synaptophysin and choline acetyl transferase expression was observed in the hippocampal CA1 region of juvenile rats using immunohistochemistry. Cognitive function was tested by the Morris water maze. RESULTS: Pathological changes were detected in glutamate-treated neural cells. Neural cell morphology remained normal after Naotan Pill intervention. Absorbance and survival rate of neural cells were significantly greater following Naotan Pill intervention, compared to glutamate-treated neural cells (P < 0.05). Synaptophysin and choline acetyl transferase expression was lowest in the hippocampal CA1 region in the model group and highest in the sham operation group. Significant differences among groups were observed (P < 0.05). Escape latency and swimming distance were significantly longer in the model group compared to the Naotan Pill group (P < 0.05). CONCLUSION: Naotan Pill exhibited protective and repair effects on glutamate-treated neural cells. Naotan Pill upregulated synaptophysin and choline acetyl transferase expression in the hippocampus and improved cognitive function in rats following hypoxia-ischemia.

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We investigate the generalized second law of thermodynamics (GSL) in generalized theories of gravity. We examine the total entropy evolution with time including the horizon entropy, the non-equilibrium entropy production, and the entropy of all matter, field and energy components. We derive a universal condition to protect the generalized second law and study its validity in different gravity theories. In Einstein gravity (even in the phantom-dominated universe with a Schwarzschild black hole), Lovelock gravity and braneworld gravity, we show that the condition to keep the GSL can always be satisfied. In f ( R) gravity and scalar-tensor gravity, the condition to protect the GSL can also hold because the temperature should be positive, gravity is always attractive and the effective Newton constant should be an approximate constant satisfying the experimental bounds.

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We study the Hawking radiation of a (4+n)-dimensional Schwarzschild black hole imbedded in space-time with a positive cosmological constant. The greybody and energy emission rates of scalars, fermions, bosons, and gravitons are calculated in the full range of energy. Valuable information on the dimensions and curvature of space-time is revealed. Furthermore, we investigate the entropy radiated and lost by black holes. We find their ratio near 1 in favor of the Bekenstein's conjecture.

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The longitudinal momentum distribution (P-//) of fragments after one-proton removal from Al-23 and reaction cross sections (sigma(R)) for Al-23,Al-24 on carbon target at 74A MeV have been measured simultaneously. An enhancement in sigma(R) is observed for Al-23 compaxed with Al-24. The full width at half maximum of the P-// distribution for Mg-22 fragments has been determined to be 232 +/- 28 MeV/c. Analysis of P-// using the Few-Body Glauber Model indicates a dominant d-wave configuration for the valence proton in the ground state of Al-23. The exotic structure in Al-23 is discussed.

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We improve the isospin dependent quantum molecular dynamical model by including isospin effects in the Skyrme potential and the momentum dependent interaction to obtain an isospin dependent Skyrme potential and an isospin dependent momentum interaction. We investigate the isospin effects of Skyrme potential and momentum dependent interaction on the isospin fractionation ratio and the dynamical mechanism in intermediate energy heavy ion collisions. It is found that the isospin dependent Skyrme potential and the isospin dependent momentum interaction produce some important isospin effects in the isospin fractionation ratio

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IEEE Reliabil Soc, Shanghai Jiao Tong Univ

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Tongji Univ, Inst Dev Study, Syst Engn Soc China, Comm Syst Dynam, Syst Dynam Soc, China Chapter, Shanghai Inst Foreign Trade, Syst Dynam Soc, Chapters Asia Pacific Area

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Based on the RS and GIS methods, Siping city is selected as a study case with four remote sensing images in 25 years. Indices of urban morphology such as fractal dimension and compactness are employed to research the characteristics of urban expansion. Through digital processing and interpreting of the images, the process and characteristics of urban expansion are analysed using urban area change, fractal dimension and compactness. The results showed that there are three terms in this period. It expended fastest in the period of 1979~1991, and in the period of 1992~2001, the emphases on urban redevelopment made it expended slower. And this is in agreement with the Siping Statistical Yearbook. This indicates that the united of metrics of urban morphology and statistical data can be used to satisfactorily describe the process and characteristics of urban expansion. © 2008 IEEE.

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利用ERA40逐日再分析资料、NCEP/NCAR2逐日再分析资料、中国740个测站日降水资料、上海台风研究所提供的西太平洋热带气旋资料、Kaplan等重建的月平均SSTA资料、NOAA逐日长波辐射(OLR)等资料,应用离散功率谱分析、带通滤波、EOF分析等统计方法,研究了东亚夏季风(EASM)的移动特征、东亚地区季节内振荡(ISO)的基本特征、季节内振荡对东亚夏季风活动的影响、季节内振荡对东亚夏季风异常活动的影响机理。主要结论如下: (1)综合动力和热力因素定义了可动态描述东亚夏季风移动和强度的指数,并利用该指数研究了东亚夏季风的爆发和移动的季节内变化及其年际和年代际变化特征。研究发现,气候平均东亚夏季风前沿分别在28候、33候、36候、38候、40候、44候出现了明显的跳跃。东亚夏季风活动具有显著的年际变率,主要由于季风前沿在某些区域异常停滞和突然跨越北跳或南撤引起,造成中国东部旱涝灾害频繁发生。东亚夏季风的活动具有明显的年代际变化,在1965年、1980年、1994年发生了突变,造成中国东部降水由“南旱北涝”向“南涝北旱”的转变。 (2)东亚季风区季节内变化具有10~25d和30~60d两个波段的季节内振荡周期,以30-60d为主。存在三个主要低频模态,第一模态主要表征了EASM在长江中下游和华北地区活动期间的低频形势;第二模态印度洋-菲律宾由低频气旋式环流控制,主要表现了ISO在EASM爆发期间的低频形势;第三模态主要出现在EASM在华南和淮河活动期间的低频形势。第一模态和第三模态是代表东亚夏季风活动异常的主要低频形势。 (3)热带和副热带地区ISO总是沿垂直切变风的垂直方向传播。因此,在南海-菲律宾东北风垂直切变和副热带西太平洋北风垂直切变下,大气热源激发菲律宾附近交替出现的低频气旋和低频反气旋不断向西北传播,副热带西太平洋ISO以向西传播为主。中高纬度地区,乌拉尔山附近ISO以向东、向南移动或局地振荡为主;北太平洋中部ISO在某些情况下向南、向西传播。 (4)季风爆发期,伴随着热带东印度洋到菲律宾一系列低频气旋和低频反气旋, 冷空气向南输送,10~25天和30~60天季节内振荡低频气旋同时传入南海加快了南海夏季风的爆发。在气候态下,ISO活动表现的欧亚- 太平洋(EAP)以及太平洋-北美(PNA)低频波列分布特征(本文提出的EAP和PNA低频波列与传统意义上的二维定点相关得到的波列不同)。这种低频分布形式使得欧亚和太平洋中高纬度的槽、脊及太平洋副热带高压稳定、加强,东亚地区的低频波列则成为热带和中高纬度ISO相互作用影响东亚夏季风活动的纽带。不同的阶段表现不同的低频模态,30~60d低频模态的转变加快了EASM推进过程中跳跃性;30-60d低频模态的维持使得EASM前沿相对停滞。 (5)30-60d滤波场,菲律宾海域交替出现的低频气旋和低频反气旋不断向西北传播到南海-西太平洋一带。当南海-西太平洋地区低频气旋活跃时,季风槽加强、东伸,季风槽内热带气旋(TC)频数增加;当南海-西太平洋低频反气旋活跃时,季风槽减弱、西退,TC处于间歇期,生成位置不集中。 (6)在El Nino态下,大气季节内振荡偏弱,北传特征不明显,但ISO由中高纬度北太平洋中部向南和副热带西太平洋向西的传播特征显著,东亚地区ISO活动以第三模态为主,EASM集中停滞在华南和淮河流域,常伴随着持续性区域暴雨的出现,易造成华南和江淮流域洪涝灾害,长江和华北持续干旱。在La Nina态下,大气季节内振荡活跃,且具有明显的向北传播特征,PNA低频波列显著,东亚地区ISO活动以第一模态单峰为主;EASM主要停滞在长江中下游和华北地区,这些地区出现异常持续强降水,华南和淮河流域多干旱;在El Nino态向La Nina态转换期,ISO活动以第一模态双峰为主,长江中下游常常出现二度梅。

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The nitrogen isotopic composition of dissolved nitrate (delta N-15-NO3-) in surface water of the Yangtze River estuary was determined in four seasons of 2006. delta N-15-NO3- ranged from 0.4 parts per thousand to 6.5 parts per thousand and varied with seasons and geographic regions, reflecting the dynamics of nitrogen cycling in the estuarine ecosystem. delta N-15-NO3- was markedly lower in February than in other seasons and exhibited conservative mixing, which was probably attributed to the NO3- being sourced from the atmospheric deposition and agricultural fertilizer. In the upper estuary, the influence of riverine inputs was important during all surveys. in the turbidity maximum zone, nitrification was found with nitrate depleted in N-15 in May, whereas denitrification resulting in heavy delta N-15-NO3- played an important role in August. More enriched delta N-15-NO3- values coinciding with losses of nitrate concentrations based on the conservative mixing model were found in the adjacent marine area in May, and may reflect obvious phytoplankton assimilation of dissolved nitrate. In this manner, delta N-15-NO3- may be a sensitive indicator of nitrogen sources and biogeochemical processing existing in this estuary in conjunction with the variations of dissolved nitrate and other environmental factors. (C) 2009 Elsevier Ltd. All rights reserved.