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51.
The mixture of platelet-activating factor (PAF) and platelets produced significant contraction of guinea pigs' bronchus, while the contraction induced by PAF alone was mild relatively, the IC50 were 6.14 x 10(-7) mol/L and 6.32 x 10(-4) mol/L respectively. There was significant difference between these two groups (P < 0.05). When the platelets were pre-incubated with ginkgolides for 10 minutes in Tris-Tyrode's buffered saline, effects of the PAF and platelets mixture were significantly inhibited (P < 0.01). Exposure of guinea pigs' bronchus to PAF in vitro resulted in a loss of beta-adrenergic receptors and responses to isoproterenol, and this effect of PAF was prevented by prior incubation of the guinea pigs' bronchus with ginkgolides (P < 0.05). The results showed ginkgolides were a potent PAF antagonist. 相似文献
52.
环境放射化学研究中几个问题的讨论 总被引:1,自引:0,他引:1
本文从辐射环境保护和公众辐射防护的角度,讨论了放射性核素在环境中的迁移行为,放射性核素与环境介质的相互作用和放射性核素在环境中的形态等涉及到环境放射化学研究方向的问题,并讨论了它们之间相互依存的关系。 相似文献
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本文介绍以PC-1500(A)型袖珍计算机为主体的地面放射性总量数据采集及处理系统的方案、硬件、软件及应用。 相似文献
57.
G Shi V Faúndez J Roos EC Dell''Angelica RB Kelly 《Canadian Metallurgical Quarterly》1998,143(4):947-955
Hereditary nonpolyposis colorectal cancer (HNPCC) is a syndrome involving a predisposition to cancers of the colon, endometrium and several other extra-colonic sites, accounting for approximately 1-5% of all colorectal cancer cases. It is not easily recognized because of a lack of distinctive clinical markers, making diagnosis and management of this disease problematic. To provide a basis for uniformity in diagnosis of HNPCC, the Amsterdam criteria were proposed and are currently in use. More recently, the discovery of four human mismatch repair genes (hMSH2, hMLH1, hPMS1 and hPMS2) has provided novel insight into the genetic basis of this disease, and raised the possibility of genetic diagnosis for management of HNPCC patients and their family members. This report summarizes the clinicopathologic aspects of HNPCC, reviews the recent genetic findings and surveillance strategies, and suggests a novel designation of certain patients as suspected HNPCC. 相似文献
58.
在压水堆核电站应急计划和应急响应中,堆底熔穿事故占有重要位置。本文用法国核电厂事故源项S3(对应于堆底熔穿事故)计算了在典型气象条件下的场外放射学的后果,根据一般防护决策原则和我国颁布的干预水平,提出了保护公众的应急防护措施的建议。 相似文献
59.
DJ Schurman A Matityahu SB Goodman W Maloney S Woolson H Shi DA Bloch 《Canadian Metallurgical Quarterly》1998,(353):175-184
Postoperative knee flexion in patients undergoing Insall-Burstein-II total knee arthroplasty at 2 years was evaluated regarding two basic questions: what groups of patients gain or lose the most flexion and what groups of patients have the best or worst postoperative flexion. Thirteen preoperative variables (maximum flexion, flexion arc, tibiofemoral angle, quadriceps strength, extensor lag, Knee Society score, Knee Society patient assessment, gender, age, height, weight, diagnosis, and surgeon) and four postoperative variable (leg length change, tibiofemoral angle, distance from patella to the joint line, and the tibial prosthesis anteroposterior translation on a lateral radiograph) were used in an attempt to explain postoperative flexion. The analysis was performed on 164 consecutive Insall-Burstein-II total knees in which the data were gathered prospectively on a time oriented medical record database. A regression tree analysis was used to identify several groups of patients, characterized by preoperative factor values, who had markedly above average performance on postoperative flexion. The preoperative factors identified include preoperative flexion, flexion arc, tibiofemoral angle, extensor lag, diagnosis, and age. The only postoperative variable of significance was tibiofemoral angle. Among the potential determinants of postoperative flexion that failed to appear predictive were the Knee Society scores and surgeon. Preoperative flexion is known to be a critical determinant of postoperative flexion in total knee replacement. However, in the current study, preoperative flexion accounted for only half of the difference between the best (122 degrees) and the worst (88 degrees) group, as determined with regression tree analysis. 相似文献
60.
该文研究了T300碳纤维单向增强的环氧复合材料,在应变率从10~(-3)/s到10~3/s范围内的冲击拉伸行为.通过对实验数据进行拟合,得出该范围内材料对应变率具有弱的敏感性,表现在破坏强度及破坏应变随应变率增加不显著变化,平均模量几乎不受应变率的影响.分析了试件的几何尺寸效应,讨论了应力波作用对破坏形态的影响以及实验中观察到的拔出现象.从应变率在10~2~10~3/s附近材料行为某些非确定性,指出在更宽范围内了解其性能的必要性. 相似文献