视力下降与颅内病变的CT分析     

张广平  何平 《CT理论与应用研究》1998,7(3):15-17

本文对１０５例主要因视力下降来我院进行头颅ＣＴ扫描患者,他们的ＣＴ片进行全面分析。作者挑选出与视力有关的颅内病３１例,以此实例来进行分析视力下降与颅内病变发生的部位的关系,同时说明影响视路的程度差别。  相似文献   

源外鼻状构造区油运移输导通道及对成藏的作用   总被引：2，自引：1，他引：1  

付广  王有功 《地质论评》2008,54(5):646-652

尚家地区为一鼻状构造,位于三肇凹陷下白垩统青山口组一段油源区之外,其石油的成藏与分布主要受输导通道的控制。能否正确认识该区石油输导通道及对成藏的作用,对于指导该区石油勘探和丰富油气成藏理论均具重要意义。采用油源对比、典型油藏解剖和成藏模式的研究方法,对尚家地区石油输导过程进行了研究,将其划分为以下3个部分：① T2源断裂是三肇凹陷青山口组一段源岩生成石油向下伏下白垩统泉头组四段扶余油层、下白垩统泉头组三段杨大城子油层“倒灌”运移的输导通道;② 被T2—T2-2断裂沟通的砂体是扶余、杨大城子油层石油从三肇凹陷向尚家地区侧向运移的输导通道;③ T2—T1-1断裂是尚家地区扶余、杨大城子油层石油向上覆下白垩统姚家组葡萄花油层运移的输导通道。采用石油输导通道和石油分布之间匹配关系的研究方法,对尚家地区输导通道对石油成藏与分布中的作用进行了研究,得到T2源断裂越发育,三肇凹陷向尚家地区侧向运移的油源越充足;被T2—T2-2断裂沟通的砂体输导通道位置和能力控制着扶余、杨大城子油层和下白垩统泉头组二段石油的分布及富集程度;T2—T1-1断裂输导通道分布控制着尚家地区葡萄花油层的石油富集区域。  相似文献   

准噶尔盆地克-百地区中生界输导层及物性下限与成藏关系   总被引：1，自引：0，他引：1  

张越迁  黄志龙  高岗  何周  刘振宇  姜向强  郭天旭 《高校地质学报》2008,14(2)

渗透性地层称为输导层,它是油气运移的通道。输导层的油气输导能力与岩层物性有密切关系。物性越好,输导能力越强,物性越差,输导能力越差。通过克-百地区中生界输导层的研究,油气输导层的物性下限不是一个固定值,输导物性下限与埋深、原油性质和总体物性条件有关。输导层的分布直接控制油藏的分布,只有分布在有效输导层上的圈闭才能形成油藏。  相似文献   

个体时空行为的规律性与可预测性研究——以上海市居民工作日活动为例   总被引：2，自引：1，他引：1  

王德  谢栋灿  王灿  殷振轩 《地理科学进展》2021,40(3):433-440

理解居民日常行为的规律性和随机性是空间行为研究从行为描述向行为预测推进的基础,对空间政策的制定具有重要意义。论文从上海市10个工作日的手机信令数据中提取个体的时空轨迹,从规律性的视角展开多方面分析。首先,根据活动的周期重现、前后联系等特征界定了无出行(包括仅有短距离出行)、仅有随机出行、有规律工作出行和有其他规律出行4种时空行为模式,发现后2种强规律性模式的人数、出行次数、出行距离的占比分别为49.3%、83.6%、82.0%。然后,测度了个体时空轨迹的熵值,推算出个体时空位置的平均可预测性高达0.84。这些结果均表明居民工作日的时空行为整体上具有非常强的规律性。在此基础上,论文还分析了不同行为模式、个体时空位置可预测性的空间分布,发现了强规律性模式人群在外围郊区密集分布等一系列特征,体现了城市空间环境的差异对行为特征和规律性的影响。  相似文献   

Fenton‐Like Degradation Comparison of s‐Triazine Herbicides in Aqueous Medium          下载免费PDF全文

Tao Chen  Zhangyun Liu  Jinting Yao  Hongyuan Hao  Feng Chen 《洁净——土壤、空气、水》2016,44(10):1315-1322

  相似文献   

高邮凹陷戴南组断层－岩性油藏断层输导性能及演化     

董才源  刘震  刘启东  罗贝维  李储华  王伟俊 《现代地质》2013,27(3):688-694

基于高邮凹陷戴南组断层－岩性油藏断层现今与成藏期垂向正应力分析,研究断层垂向封闭性演化规律,并结合断层垂向输导模式划分,预测高邮凹陷戴南组断层－岩性油藏有利分布区。研究结果表明,断层垂向封闭性的临界正应力值为13.8 MPa,多数控藏断层在成藏期开启作为输导通道,现今则封闭成为遮挡条件,但偶有例外,邵深1油藏控藏断层在成藏期与现今皆封闭,此类油藏极有可能是自生自储;高邮凹陷发育有两种垂向输导模式,分别为高通和低通垂向输导模式,其中高通垂向输导模式中戴南组底砂岩发育,低通垂向输导模式戴南组底砂岩不发育。在断层封闭性演化研究和输导模式划分的基础上,认为联12油藏以东－永22油藏以西及邵14油藏以东伯东地区是高邮凹陷戴南组断层－岩性油藏发育的有利区带,邵深1油藏西北的邵伯次凹深处是断层－岩性油藏发育的较有利区带。  相似文献   

The roles of serine protease, intracellular and extracellular phenoloxidase in activation of prophenoloxidase system, and characterization of phenoloxidase from shrimp haemocytes induced by lipopolysaccharide or dopamine     

谢鹏  潘鲁青  徐武杰  岳峰 《中国海洋湖沼学报》2013,31(5):1018-1027

We investigated the effects of lipopolysaccharide(LPS) and dopamine(DA) on the activation of the prophenoloxidase(proPO) system of Litopenaeus vannamei.LPS and DA were shown with a negative dose-dependent effect on hyalne cells(HC),semi-granular cells(SGC),large granular cells(LGC),and total haemocyte count(THC).When haemocytes were treated with LPS or DA,serine proteinase activity and intracellular phenoloxidase(PO) activity were significantly reduced,but extracellular PO activity increased significantly.These findings indicated that the reduction in haemocyte counts was mainly because of the degranulation and activation of the proPO system from semi-granule and large granule cells.The PKC inhibitor,chelerythrine,and the TPK inhibitor,genistein,had an inhibitory effect on extracellular PO activity,while serine proteinase and intracellular PO activity increased.This suggests that the LPS and DA induce the activation of proPO in haemocytes via PKC and TPK-related signaling pathways,but serine proteinase may be activated only by PKC,as the genistein effects were not statistically significant.Electrophoresis analysis revealed that POs induced by LPS or DA have the same molecular mass and high diphenolase activity.Two PO bands at 526 kDa and 272 kDa were observed in PAGE,while in the haemocyte lysate supernatant(HLS),only a 272-kDa band was observed.This band was resolved after SDS-PAGE under non-reducing and reducing conditions into two groups of POs,166 kDa and 126 kDa,and 78.1 kDa and 73.6 kDa,respectively,suggesting that PO in L.vannamei is an oligomer,which may have different compositions intra-and extracellularly.  相似文献   

长春城市蔓延机理与调控路径研究   总被引：5，自引：0，他引：5  

黄晓军  李诚固  黄馨 《地理科学进展》2009,28(1)

城市蔓延是当今世界许多大城市普遍面临的问题.20世纪90年代以来,长春城市蔓延特征逐渐凸显并日趋严重,随之产生许多经济、社会和生态方面的负面效应.城市经济的高速发展、人口增长与空问扩散、开发区建设、机动化与交通设施建设、住宅扩散与郊区房地产开发以及城市规划的宏观导向等因素,都在不同程度上导致了长春的城市蔓延.为遏制长春"摊大饼"式的空间扩张和进一步的城市蔓延.借鉴国内外有效控制城市蔓延的相关理念和应对策略,从城市增长模式、空间优化布局、房地产开发控制与引导、快速交通体系建设、耕地与生态系统保护等五个方面提出了长春城市发展过程中消减城市蔓延的调控路径.  相似文献   

三倍体虹鳟(Oncorhynchus mykiss)卵巢分化及滞育的调控机制研究     

徐革锋  牟振波  陈怀发  黄天晴  王炳谦  谷伟  户国  韩英 《海洋与湖沼》2017,48(2):358-367

尽管与性别决定和分化的相关基因在二倍体虹鳟中已被鉴定出来,如Cyp19a1a、Foxl2、Dmrt1、Amh和Sox9,但关于三倍体雌性虹鳟独特性腺表型及其相关性别控制基因的表达规律仍未得到深入研究,尤其是早期卵巢发育阻滞导致的生殖细胞去分化特征。因此,本研究以三倍体雌性虹鳟性腺发育中起重要调控作用的特异候选基因作为重点研究对象,辅助性腺体细胞与生殖细胞分化方向的组织学证据和类固醇激素表达规律,验证了各基因间的级联调控关系。结果表明,虹鳟三倍体与二倍体卵巢的分化特征基本一致。虹鳟二倍体与三倍体性腺分别在84dpf和98dpf就已分化为卵巢。但三倍体虹鳟卵巢分化存在障碍,早期发育停滞,卵原细胞及其滤泡细胞数量有限。Foxl2和Cyp19a1a在二倍体虹鳟卵巢和精巢中均有表达,它们在卵巢中表达量均呈逐渐升高趋势,但在精巢中的表达量非常低;这两个基因在雌性三倍体虹鳟性腺中的表达呈先升高后降低的趋势,其表达量均在8月龄时期达到最大。Dmrt1、Amh和Sox9在二倍体精巢和雌性三倍体卵巢中的表达均呈不断上调趋势,这些基因上调可能与血清睾酮含量的增加相关,因为在10月龄时期这两种鱼的血清含量相对较高,而这三个基因在二倍体虹鳟卵巢中的表达却呈下调趋势。因此本研究认为,维持鱼类卵巢分化需要持续高水平的雌激素,这可能是脊椎动物进化过程中的一个保守特征。可以推断雌性三倍体虹鳟卵巢滞育将导致其体细胞去分化,这对于Cyp19a1a表达及雌二醇合成存在抑制作用。因为这些雌激素是用来维持它们分化和继续发育的,可能产生一个负反馈圈,之后去分化会增强。  相似文献   

Mineral types and organic matters of the Ordovician-Silurian Wufeng and Longmaxi Shale in the Sichuan Basin,China: Implications for pore systems,diagenetic pathways,and reservoir quality in fine-grained sedimentary rocks     

《Marine and Petroleum Geology》2017

Mineral types (detrital and authigenic) and organic-matter components of the Ordovician-Silurian Wufeng and Longmaxi Shale (siliceous, silty, argillaceous, and calcareous/dolomitic shales) in the Sichuan Basin, China are used as a case study to understand the control of grain assemblages and organic matter on pores systems, diagenetic pathway, and reservoir quality in fine-grained sedimentary rocks. This study has been achieved using a combination of petrographic, geochemical, and mercury intrusion methods. The results reveal that siliceous shale comprises an abundant amount of diagenetic quartz (40–60% by volume), and authigenic microcrystalline quartz aggregates inhibit compaction and preserve internal primary pores as rigid framework for oil filling during oil window. Although silty shale contains a large number of detrital silt-size grains (30–50% by volume), which is beneficial to preserve interparticle pores, the volumetric contribution of interparticle pores (mainly macropores) is small. Argillaceous shale with abundant extrabasinal clay minerals (>50% by volume) undergoes mechanical and chemical compactions during burial, leading to a near-absence of primary interparticle pores, while pores preserved between clay platelets are dominant with more than 10 nm in pore size. Pore-filling calcite and dolomite precipitated during early diagenesis inhibit later compaction in calcareous/dolomitic shale, but the cementation significantly reduces the primary interparticle pores. Pore-throat size distributions of dolomitic shale show a similar trend with silty shale. Besides argillaceous shale, all of the other lithofacies are dominated by OM pores, which contribute more micropores and mesopores and is positively related to TOC and quartz contents. The relationship between pore-throat size and pore volume shows that most pore volumes are provided by pore throats with diameters <50 nm, with a proportion in the order of siliceous (80.3%) > calcareous/dolomitic (78.4%) > silty (74.9%) > argillaceous (61.3%) shales. In addition, development degree and pore size of OM pores in different diagenetic pathway with the same OM type and maturity show an obvious difference. Therefore, we suggest that the development of OM pores should take OM occurrence into account, which is related to physical interaction between OM and inorganic minerals during burial diagenesis. Migrated OM in siliceous shale with its large connected networks is beneficial for forming more and larger pores during gas window. The result of the present work implies that the study of mineral types (detrital and authigenic) and organic matter-pores are better understanding the reservoir quality in fine-grained sedimentary rocks.  相似文献