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101.
通过对河南偃龙煤田地质产状的综合分析,为防止煤田立井井筒开拓出现立井井筒井壁破裂现象,采用立井可伸缩式罐道接头技术,改进井壁结构,使立井井壁具有"抗"、"让"或"抗让结合"的特性,以承受岩体下沉而产生垂直附加力的影响,保障井筒提升容器的安全、高效运行。 相似文献
102.
103.
Objective: Study blood vessel injury and gene expression indicating vascular endothelial cell apoptosis induced by mannitol with and without administration of anti-oxidative vitamins. Methods: Healthy rabbits were randomly divided into four groups. Mannitol was injected into the vein of the rabbit ear in each animal. Pre-treatment prior to mannitol injection was per- formed with normal saline (group B), vitamin C (group C) and vitamin E (group D). Blood vessel injury was assessed under electron and light microscopy. In a second experiment, cell culture specimen of human umbilical vein endothelial cells were treated with mannitol. Pre-treatment was done with normal saline (sample B), vitamin C (sample C) and vitamin E (sample D). Total RNA was extracted with the original single step procedure, followed by hybridisation and analysis of gene expression. Results: In the animal experiment, serious blood vessel injury was seen in group A and group B. Group D showed light injury only, and normal tissue without pathological changes was seen in group C. Of all 330 apoptosis-related genes analysed in human cell culture specimen, no significant difference was seen after pre-treatment with normal saline, compared with the gene chip without pre-treatment. On the gene chip pre-treated with vitamin C, 45 apoptosis genes were down-regulated and 34 anti-apoptosis genes were up-regulated. Pre-treatment with vitamin E resulted in the down-regulation of 3 apoptosis genes. Conclusion: Vitamin C can protect vascular endothelial cells from mannitol-induced injury. 相似文献
104.
Proliferation of endothelial cell on polytetrafluoroethylene vascular graft materials carried VEGF gene plasmid 总被引:1,自引:0,他引:1
Tao SF Chen L Zheng YX Xu Y Chen J Yu H 《Journal of Zhejiang University. Science. B》2006,7(6):421-428
Objective: To investigate whether vascular endothelial growth factor (VEGF) gene plasmid carried by polytetrafluoroethylene (PTFE) vascular graft materials could transfect endothelial cells (ECs) and promote their growth. Methods: PTFE vascular graft materials carried with pCDI-hVEGF121, pCDI or pEGFP were incubated in Tris-buffer solution and the values of optical density of 260 nm at different time were plotted, then the DNA controlled release curve was made. ECs derived from human umbilical vein were seeded on the pCDI-hVEGF121/pCDI/pEGFP-PTFE materials or tissue culture plates, ECs numbers were counted and VEGF protein concentrations at different time were measured by enzyme-linked immunoadsorbent assay method. Green fluorescent protein (GFP) expression in ECs on pEGFP-PTFE materials was examined with fluorescence mi- croscopy. Results: The controlled release curve showed that the gene released from PTFE materials was rapid within 8 h, then slowed down and that the gene released continuously even after 72 h. At 24, 72 and 120 h, ECs number and proliferation rate of pCDI-hVEGFI21-PTFE materials were higher than those ofpCDI or pEGFP-PTFE materials (P〈0.05). VEGF protein concentration of pCDI-hVEGF121-PTFE materials was higher than that of pC DI or pEGFP-PTFE materials at 6, 24, 72 and 120 h (P〈0.01). GFP expression in ECs on the pEGFP-PTFE materials could be detected by fluorescence microscopy. Conclusion: PTFE graft can be used as a carrier of VEGF gene plasmid, VEGF gene carried by PTFE can transfect ECs and promote ECs growth. 相似文献
105.
赫鲁晓夫问我:“毛泽东刚才是不是在骂我?”我不便直译.只好说:“毛泽东说的是生气的话,但他不是骂您。”他半信半疑地看着我.又看着毛泽东。也对我低声说出一句难听的俄语 相似文献
106.
李振亮 《重庆第二师范学院学报》2013,26(3):8-12
回顾了群体平衡模型(Population Balance Model,PBM)应用于絮凝过程中絮体粒经分布模型的相关研究,主要包括区间离散法求解PBM,絮体聚并模型和破碎模型等。近年来,描述聚并效率的"曲线模型",与Kol-mogorov尺度相关的破碎频率模型,絮体的分形特征等方面得到了较大的进展。但絮凝过程动力学的研究还并不完善,絮体粒径的动力学演变过程还需要更多的研究。未来的研究应集中于:(1)更多的实验验证,尤其是絮体破碎行为的测定;(2)结合絮凝机理,提出更有效的絮体聚并、破碎模型;(3)更合理的流体剪切力描述。 相似文献
107.
根据ISO 7198和YY 0500-2004,通过对常规织物强力仪夹持件的改进设计,在保持试样管状形态下,实现对人造血管周向和轴向拉伸性能的测试,并进行了验证性试验。周向与轴向拉伸夹持件可测直径2~45 mm的管状试样,并配置三档精度范围的传感器5.0、0.5、0.1 kN,满足不同管状材料的测试要求。验证结果表明,直径4 mm机织人造血管周向断裂强度(14.31 N/mm)大于轴向断裂强度(13.40 N/mm),这与临床上人造血管在周向需要更强的结构是相吻合的,且实验指标的CV值在一个可接受的范围内;另直径6 mm的3种不同结构的人造血管的周向断裂强度CV值在0.61%~3.51%,说明该测试仪器的精密度较高,重现性较好。该管状拉伸夹持件具有操作简便、功能性强和数据精准的优点。 相似文献
108.
1.互相猜疑
“这么晚才回家,你和谁约会去了?”丈夫一回家,妻子就不停地翻他的手机,检查有没有陌生的电话号码和肉麻的短信,甚至当他与异性多说几句话也醋意横生。 相似文献
109.
杨晓东 《岳阳职业技术学院学报》2008,23(2):61-64
冠心病的病理学基础是动脉粥样硬化.目前认为动脉粥样硬化的形成和斑块的破裂与细胞外基质的破坏和重构有密切关系,而基质金属蛋白酶(MMPs)是降解细胞外基质的重要酶类.对近年来关于MMPs的结构、功能、基因表达以及在冠心病中的作用的研究取得的成果进行了综述. 相似文献
110.