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91.
建立了较完整的估计重油和沥青中饱和碳浓度数方法,其中包括环烷桥头碳、环烷甲基取代碳、环烷烷基(≥C2)取代碳等。基于理论分析,建立了估计环间的桥链和各种平均结构参数的方法,包括平均芳环环核数和环烷环环核数、芳环和环烷环烷工取代度、单元片上芳环和环烷环数。从实验数据出发,提出了烷基链长分布的公式。 相似文献
92.
African Americans experienced massive internal migrations that shifted more than 6 million Southern-born blacks to other sections of the United States over the past century, a trend that only recently has been reversed. Whenever mass migration takes place, there is an opportunity to examine the role of the native and relocated environments in the development of disease. This article examines those relationships for diabetes mellitus, a group of diseases that disproportionately affect African-Americans relative to other racial and ethnic groups in the United States. Age-specific and age-adjusted rates with 95% confidence intervals were calculated for males and females for combinations of five regions of birth and four regions of residence at time of death. Southern-born males had statistically significantly higher death rates from diabetes than did their counterparts who died in the same regions in 9 of 16 comparisons. For females, those born in the South had statistically significantly higher rates in 15 of 16 comparisons. The results of this study indicate that place of birth and early life experiences are statistically associated with diabetes mortality among African Americans regardless of place of residence at time of death. 相似文献
93.
94.
Resection was carried out in 1,025 of 1,654 patients with cancer of the esophagus or esophagogastric junction at the Peking Medical College Hospitals in China from 1953 through 1973. All cancers of the esophagus were squamous cell carcinomas except for five adenocarcinomas. A lesion localized within the esophageal wall was found in 55% and lymph node metastasis in 41.3% of the patients undergoing resection. All cancers of the esophagogastric junction were adenocarcinomas. The tumor had invaded beyond the boundaries of the stomach in 76.7% of these patients, and positive nodes were found in 61% of the patients. The rate of resectability was 81.2% for esophageal cancer and 74% for cancer of the esophagogastric junction. Surgical mortality after resection was 4.9% (50/1,025). The 5-year survival after resection was 20.9% (214/1,025). Better results were found following complete resection: 24% (210/875) for all patients, 28.2% (162/575) for patients with cancer of the esophagus, and 16% (48/300) for patients with cancer of the esophagogastric junction. Late survival at 10, 15, and 20 years after resection of esophageal cancer was 20%, 12%, and 7.4%, respectively. The favorable prognostic factors after resection of esophageal cancer were tumor of the lower third of the esophagus, the absence of lymph node involvement, and the presence of a localized lesion. The 5-year survival for patients with cancer of the lower third of the esophagus was 32.7%. It was 64.2% for patients with a localized lesion with negative nodes in this subgroup. 相似文献
95.
E. Pujade-Lauraine H. Lu S. Mirshahi J. Soria C. Soria A. Bernadou E. K. O. Kruithof H. R. Lijnen P. Burtin 《International journal of cancer. Journal international du cancer》1993,55(1):27-31
We studied the plasminogen activation system in tumor tissue by measuring the antigen level of the 2 plasminogen activators, tissue-type (t-PA) and urokinase-type (U-PA) and their inhibitors, plasminogen-activator inhibitors type-1 (PAI-1) and type-2 (PAI-2) in the tissue extracts of 43 human benign and malignant ovarian tumors. U-PA levels were significantly higher in malignant than in benign tumors. In addition, U-PA antigen levels were higher in the metastatic tissue of advanced disease (FIGO stage III) than in the primary localized tumor (FIGO stage I/II). Also PAI-1 concentrations tended to be higher in malignant than in benign tumors, but this difference was not statistically significant. In contrast, t-PA levels were lower in metastatic than in non-metastatic tumors, whereas PAI-2 levels were unrelated to the stage of ovarian malignancy. These results were integrated in a plasminogen-activation-dependent malignancy index (U-PA × PAI-1/t-PA). This index distinguished the different groups of benign ovarian tumors, localized and metastatic ovarian carcinomas better than U-PA levels. It could be useful as a prognostic indicator in ovarian cancer © 1993 Wiley-Liss, Inc. 相似文献
96.
Fictive oesophageal peristalsis evoked by activation of muscarinic acetylcholine receptors in rat nucleus tractus solitarii 总被引:1,自引:0,他引:1
The aim of the present study was to determine if muscarinic acetylcholine receptor-mediated peristaltic rhythmogenesis in the rat oesophagus is a central motor program that can be generated without peripheral sensory support. In anaesthetized male Sprague-Dawley rats, pressure-ejection of glutamate (10–20 pmol) and muscarine (5–10 pmol) in the subnucleus centralis of the nucleus tractus solitarii (NTSC ) evoked monophasic pressure waves and rhythmic oesophageal peristalsis, respectively, but did not change mean arterial blood pressure or respiration. Application of muscarine (50–100 pmol) to the NTS extraventricular surface evoked rhythmic multi-unit burst discharges in the compact formation of the nucleus ambiguus (AMBC ) that led to oesophageal peristalsis in a phase-locked manner. Evoked rhythmic AMBC activity persisted during neuromuscular blockade with curare, although the peak frequency of individual bursts was decreased. In a brainstem slice preparation, intracellular and whole cell patch recordings from AMBC neurones during focal stimulation of the NTSC region with muscarine revealed rhythmic depolarizing waves that showed a pattern similar to that of rhythmic oesophageal peristalsis. The present findings support the concept that medullary circuits comprising premotor neurones of the NTSC are intrinsically capable of generating rhythmic oesophagomotor output, but are subject to a powerful modulation by peripheral sensory feedback. 相似文献
97.
98.
医院融资经营提高资本利用质量 总被引:1,自引:0,他引:1
着重从资本运作中最主要的手段——融资,去剖析医院以融资方式实现医疗规模迅速扩张的全过程。介绍了经营租赁与融资租赁及其优缺点,并附案例加以说明。 相似文献
99.
松花粉对人肺成纤维细胞增殖活性影响的实验研究 总被引:1,自引:0,他引:1
目的 :研究松花粉对人肺成纤维细胞增殖的影响 ,探讨中药松花粉可能的作用机理。方法 :松花粉作用于人肺成纤维细胞不同时间后观察细胞生长速度 ,应用台盼蓝对细胞进行染色 ,测定细胞死亡率。松花粉浓度分别为 10 0、2 0 0、40 0、80 0mg·L-1,以未经松花粉处理的细胞为对照。结果 :松花粉作用于人肺成纤维细胞能够明显促进细胞群体倍增水平 ,降低死亡细胞数目 ,且呈剂量依赖关系。结论 :松花粉可通过促进细胞生长而影响细胞增殖。 相似文献
100.
人白细胞介素12双亚基共表达真核载体的构建 总被引:2,自引:0,他引:2
目的:为满足基因治疗的需要构建人白细胞介素12(hIL-12)双亚基共表达质粒。方法:先从人胚肾组织的逆转录产物中用PCR方法扩增出它的两个亚基P40和P35的cDNA全长,分别克隆入真核表达载体pcDNA3.1( /-)中构建单亚基质粒——P( )/P40和P(-)/P35,然后再将二者串联克隆入真核表达载体poDNA3.1( )中得到P( )/IL-12质粒。脂质体转染HepG2后24,48h ELISA检测细胞培养上清内hIL-12蛋白质表达。结果:P( )/IL-12质粒经酶切和测序证明两亚基连接方向正确,序列无突变;ELISA检测细胞上清结果证实可表达hIL-12蛋白质。结论:成功构建P40和P35双亚基真核共表达质粒——P( )/IL-12,为模拟hIL-12生理表达方式,简化hIL-12基因治疗操作奠定了基础。 相似文献