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931.
目的:观察宣痹通络膏对急性痛风性关节炎(AGA)模型大鼠髓样分化因子88(MyD88)表达的影响。方法:将60只雄性Wistar大鼠随机分为6组:宣痹通络膏低、中、高剂量组(简称为低、中、高剂量组),秋水仙碱组,模型组,空白组,每组各10只。于大鼠踝关节局部注射尿酸钠晶体混悬液制备AGA模型,造模后当天开始进行药物干预,连续3 d。观察各组大鼠不同时间点的关节肿胀度,血清及滑膜组织中MyD88蛋白表达水平,踝关节滑膜组织病理形态学变化。结果:关节肿胀度比较,24 h时,模型组较空白组上升;48h时,高剂量组、秋水仙碱组较模型组降低;72 h时,各给药组均较模型组降低,差异均有统计学意义(P<0.05)。与空白组比较,模型组大鼠血清、滑膜组织MyD88含量显著升高(P<0.01);与模型组比较,各给药组血清MyD88含量以及高、中剂量组和秋水仙碱组滑膜组织MyD88蛋白含量均降低,差异均有统计学意义(P<0.05或P<0.01)。与模型组相比,各药物组的踝关节滑膜组织病理形态得到改善。结论:宣痹通络膏可能通过下调MyD88蛋白表达,从而改善AGA模型大鼠的踝关节滑膜损伤。 相似文献
932.
Urban land-use change is the result of coupling interaction between planning and environment systems. The aim of our study was to construct an effective model to show how the urban land-use changes under the planning–environment interaction system with multi-hierarchy and major function oriented zoning. Combining the Cellular automata (CA) model with logistic regression model, the proposed multi-hierarchal vector CA model (MH-VCA3) was constructed by mining multi-hierarchal land-use transition rules under the planning–environment interaction system. Taking Jiangyin City (China) as an example, we compared the simulated result of the proposed model to those of the well-accepted Logistic CA and traditional multi-level CA models to demonstrate the effectiveness of the consideration of top-down decomposition constraint and bottom-up updating. Furthermore, by simulating the land-use changes under different population regionalization scenarios, we found that in order to form the spatial pattern of “agglomeration in the north and ecology in the south,” the planned population growth at the global hierarchal level should be allocated to the district units according to the law of Central district > Chengxi district > Chengdong district > Chengnan district > Chengdongnan district. The proposed model is expected to provide scientific support for the formulation of urban planning schemes in the future. 相似文献
933.
冰雪旅游是推动冰雪经济与旅游产业高质量融合发展的重要途径,现已成为文旅产业中最具潜力的领域之一。然而在全球气候变化的影响下,冰雪旅游发展面临严峻挑战。文章以北京市为例,运用结构方程模型对冰雪旅游情境中城市居民的气候变化感知、感知价值、旅游意向和环境责任行为等变量间的影响关系及其形成机制进行分析。研究发现:(1)气候变化感知分为气候变化表征和气候变化风险两个维度,且两者显著正向影响冰雪旅游感知价值。同时,气候变化风险显著正向影响旅游者环境责任行为。(2)冰雪旅游感知价值显著正向影响冰雪旅游意向和环境责任行为。(3)冰雪旅游意向显著正向影响环境责任行为。(4)旅游经历在气候变化感知对冰雪旅游意向和环境责任行为的影响关系中具有显著的正向调节作用。本研究对厘清冰雪旅游情境下气候变化感知对游客环境责任行为的复杂影响机理具有重要的理论价值,同时也能够在一定程度上为相关部门把握“后冬奥”黄金机遇,推动冰雪旅游高质量发展提供决策参考。 相似文献
934.
Upper ocean responses to the passage of sequential tropical cyclones over the northwestern South China Sea(SCS) in 2011 were investigated using satellite remote sensing data,Argo reanalysis data,and an array of mooring data.We found that the sea surface low temperature region lasted for more than 38 days and two phytoplankton blooms occurred after the passage of sequential tropical cyclones.The upper ocean cooling reached 2-5℃ with a right-side bias was observed along the typhoon track to about 200 km.The maintenance of low temperature region and the two phytoplankton blooms were mainly driven by upwelling and near-inertial turbulence mixing induced by the sequential tropical cyclones.The first phytoplankton bloom appeared on the 7~(th) day after the passage of the three tropical cyclones,and the chlorophyll-a(chl-a) concentration increased by 226%,which may be mainly driven by typhoons induced upwelling.The second phytoplankton bloom occurred on the 30~(th) day,the chl-a concentration increased by290%.Further analysis suggested that only the typhoons with similar characteristics as Nesat and Nalgae can induce strong near-inertial oscillation(NIO).Strong turbulent mixing associated with the near-inertial baroclinic shear instability lasted for 26 days.The measured mean eddy diffusivity in the upper ocean was above 10~(-4) m~2/s after typhoon Nesat.Enhancement of the turbulent mixing in the upper ocean helped to transport nutrient-rich cold waters from the deep layer to the euphotic layer,and is a maj or mechanism for the long-term maintenance of low temperature region as well as the second phytoplankton bloom. 相似文献
935.
Journal of Oceanology and Limnology - The Kuroshio Extension (KE) is one of the most eddy-energetic regions in the global ocean. However, most mesoscale eddy studies in the region are focused on... 相似文献
936.
Multi-Time Scale Analysis of Runoff at the Yangtze Estuary Based on the Morlet Wavelet Transform Method 总被引:1,自引:1,他引:0
KUANG Cui-ping SU Ping GU Jie CHEN Wu-jun ZHANG Jian-le ZHANG Wan-lei ZHANG Yong-feng 《山地科学学报》2014,(6):1499-1506
Runoff series of the Yangtze River presents an intricate variation tendency under the reinforced influence of human activities.The Morlet Wavelet Transform method has been applied to analyze the annual runoff data from 1950 to 2011 at the Yangtze River Estuary.It can clearly reveal the multi-time scales structure,break point,change and distribution of periodic variation in the different time scales of the runoff series.The main conclusions are that:1) Repeated periodic oscillations accompanied by an extremely large fluctuation are presented in the runoff series with an obvious difference between wet and dry years,and the major periods of the time series are about 3,8,16 and 23 years respectively.Among them,the presented maximum periodic oscillation is 23 years scale.2) In the 23-year time scale,the wet periods are 1950-1958,1969-1980 and 1992-2003,and the dry periods are 1959-1968,1981-1991 and 2004-2011.3) It can be predicted from the view of long time scales that the low annual runoff will likely occur in the near future. 相似文献
937.
938.
通过紫外分光光度计分析和扫描电镜观察,开展不同温度下酸性流体与斜长石相互作用实验得出:①在低温条件下斜长石较稳定,以溶解为主;在高温条件下,斜长石不稳定,以溶蚀、溶解为主;随反应温度升高,质量损失增大。②斜长石沿解理形成条带状溶孔,沿表面形成粒内溶孔。③在160℃和190℃条件下,形成新生高岭石沉淀,温度升高高岭石晶形变好,实验反应强度增大。④随反应温度升高, K+、 SiO2和矿化度浓度升高。 相似文献
939.
ZHU Bingqi YU Jingjie QIN Xiaoguang Patrick RIOUAL LIU Ziting XIONG Heigang 《地理学报》2014,24(1):177-190
Sandy desert landscape is a geological product of arid climate and abundant sand materials supply in natural conditions, therefore the formation of sandy desert is an ideal studying object for understanding the interaction between various stratigraphic/epigenetic spheres of the earth system. However, until now, the knowledge about the provenance and formation of these deserts in Xinjiang, Central Asia is diverse and inconsistent, a systematic review is necessary. Ancient aeolian sand sediments in the internal areas of these deserts and their twin dust deposits in the Cenozoic strata surrounding the Xinjiang deserts are direct and indirect clues reflecting the provenance of sand materials and the formation and evolution of deserts. Based on the geochemical, mineralogical and isotopic evidences of desert sands and relevant deposits in the peripheral regions, this paper reviews the research progress on the development of the sandy deserts in Xinjiang, Northwest China. Many proofs proposed that desert sands in Xinjiang were mainly sourced from the ancient pluvial, alluvial and fluvial sediments and were eventually achieved because of the local sand supply. It pointed out that the settings of tectonic structure in Xinjiang had made sediments both in the Tarim Basin and the Junggar Basin being influenced greatly by regional hydrological system and aeolian processes originated from the planetary wind system of westerly, the East Asian winter monsoon and the topographical mountain-valley winds. However, the directions of transportation paths are different between the hydrological dynamics and the aeolian dynamics, which are decided by the slantwise structures of the basins tectonics and the regional atmospheric circulation routes, respectively, and have determined anisotropies of the transport pathway of these sediments delivered by different agents. This results in a geological cycle of detrital sediment transportation in the two large basins and thus largely increases the degree of sediment mixing, alternation and recycle between younger and older sediment sources, as well as the complexity and diversity of sand provenances. 相似文献
940.
城市河道是集城市生态保育、娱乐游憩、居住生活、景观等多重功能于一体的开放空间。对城市河道公共休闲空间的利用目前存在价值利用与控制难以协调的矛盾,构建城市河道公共休闲价值评价指标对城市河道休闲空间的规划与开发具有重要的现实意义。基于目前公众对城市河道休闲的识别要素,综合国内外学者对休闲空间评价、城市河道生态健康评价等研究,将城市河道公共休闲空间适宜性指标归纳为资源特性、形态特性、功能特性、文化特质、公共特性等5个维度共42项指标;综合考虑指标的代表性和易操作性等特征,在指标权重确定上,使用最常用的关联矩阵法,反映各指标的重要性差异;利用确定的指标体系和权重测度了北京城区已治理的14条河道的公共休闲适宜度。结果表明,北京市城市河道普遍存在生态景观特征较好,但实用性有待加强的现实问题。 相似文献