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通过研究二连盆地赛汉塔拉凹陷中洼槽陡坡带的含鲕粒块状细砂岩从岩性特征、沉积结构及构造特征、粒度特征、测井曲线特征、地震反射特征以及对其形成机理的分析,认为赛83x含油砂岩体为在半深湖一深湖环境形成的滑塌浊积扇沉积.这种类型的滑塌浊积扇具备分选、磨圆度、物性较好等条件,尤其是此类砂岩体往往被形成于深湖一半深湖相还原环境的深灰色、灰黑色泥岩--成熟烃源岩所包围,易形成岩性圈闭,有利于油气的运移和聚集成藏,是断陷湖盆陡坡带油气勘探的重要目标. 相似文献
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C Aufricht A Balbisi C Gerdov T Müller MA Lothaller E Balzar 《Canadian Metallurgical Quarterly》1995,207(2):59-62
A 10-year-old German shepherd dog presented with a periodontal 10 mm interproximal defect between the left mandibular fourth premolar and first molar teeth. Bone graft removed from the caudoventral portion of the ipsilateral hemimandible was placed in the defect as a component of the periodontal treatment plan. The use of bone graft likely contributed to periodontal pocket reduction. 相似文献
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A competitive enzyme-linked immunoadsorbent assay (ELISA) technique has been developed to facilitate quantitative analysis of the earliest step in the initiation of the extrinsic pathway of coagulation, i.e., complex formation of factor VII/VIIa with tissue factor. The ELISA measures the binding of biotinylated human plasma factor VII to relipidated recombinant human tissue factor. Quantitation of the relative affinity (expressed as IC50) of any factor VII molecular population or structural analogue for tissue factor can be determined by competitive binding. Subnanomolar concentrations of both wild-type recombinant human factor VII (rFVII) and rFVII(R152Q), a mutation at the FVII activation site, competed effectively with biotinylated plasma-derived factor VII in binding to tissue factor. In contrast, the affinity of rFVII(R79Q), a mutation in the first epidermal growth factor-like domain, was 12-fold lower. Following activation of rFVII(R79Q), its affinity for tissue factor and enzymatic activity increased 4-fold and 6-fold, respectively. For wild-type rFVII, enzymatic activity rose significantly following activation. However, its affinity for tissue factor was unchanged. We conclude that both the activation state of factor VII and the mutation of amino-acid residues within the first epidermal growth factor-like domain may alter the affinity of factor VII for tissue factor. 相似文献
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The architecture of normal colonic mucosa suggest that terminally differentiated epithelial cells near the top of the crypt are extruded into the colonic lumen. Morphological studies have identified apoptotic cells among the differentiated phenotypes near the crypt-lumen interface, suggesting a link between pathways of differentiation, apoptosis, and cellular shedding. We studied these processes in HT29 and SW620 cells and found that compared to adherent cells, those cells which were shed during standard, uninduced culture conditions exhibited nonrandom DNA fragmentation characteristic of apoptosis. Moreover, these apoptotic cells, which accumulate in the media, exhibited a more differentiated phenotype. Because short-chain fatty acids (SCFAs) are natural effectors of colonic cell differentiation in vivo, we investigated the specificity of three 4-carbon atom SCFAs on potentiating differentiation and apoptosis, and thus accumulation of shed cells in the conditioned media, in these colonic carcinoma cell lines. Whereas the unbranched SCFA butyrate induced a more differentiated phenotype and enhanced apoptosis, two derivatives of butyrate, branched isobutyric acid and a nonmetabolizable fluorine-substituted analogue, heptafluorobutyric acid, were ineffective in inducing either differentiation or apoptosis. Thus, potentiated differentiation and apoptosis in colonic carcinoma cells were linked to SCFA structure and, most likely, utilization. 相似文献
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OBJECTIVE: To study the effects of thevetoside (TS), a cardiac glycoside, and an inhibitor of Na+, K(+)-ATPase, on tumor cells cultured in vitro. METHODS: The cytotoxic effects of TS on tumor cells were determined by trypan blue dye exclusion, neutral red vital staining and clonogenic assay. The time-effect relationship and growth inhibition of tumor cells by TS were assayed with trypan blue exclusion method. RESULTS: TS at low doses (0.005-0.1 mg.L-1), with dose dependence, was able to kill SMMC-7721, SGC-7901 and HeLa cells. IC50 values for SMMC-7721, SGC-7901 and HeLa cells were 0.007, 0.011 and 0.018 mg.L-1 by trypan blue dye exclusion test and 0.016, 0.055 and 0.078 mg.L-1 by neutral red vital staining test. TS inhibited the clonal forming rate of SMMC-7721 and SGC-7901 significantly with IC50 values of 0.021 and 0.036 mg.L-1, respectively. Only when the cells were continuously treated with TS for more than 8 hours, the drug-induced cell lethality could be displayed and strengthened quickly. The growth of tumor cells was notably inhibited after they were exposed to 0.1 microgram/ml of TS for 12 hours. All the experimental results of antitumor activity in vitro showed that SMMC-7721 was most sensitive to TS among the three kinds of tumor cells. CONCLUSIONS: TS has cytotoxic action on tumor cells cultured in vitro and this lethal effect must have an action process, in which tumor cells are not dead but suffer from deadly injury and lost the capability of unlimited proliferation. 相似文献