修正正交分段线性函数及其在线性与时变线性系统中应用

把分段线性函数和斜波脉冲函数进行统一处理，定义成新的函数，使得新的函数既保持了原先两种函数的基本特性，又获得微分和积分递推算法。应用中具有方便，快速计算的优点。     

Fluid shear induced endothelial cell detachment from glass - influence of adhesion time and shear stress

In this study, human umbilical vein and human saphenous vein endothelial cells were seeded on glass and exposed to fluid shear in a parallel-plate flow chamber. Cell retention, morphology and migration were studied as a function of shear stress and of adhesion time prior to exposure to shear. Three-hour and 24-h adhesion times gave rise to comparable cell retention values after 2 h of flow for both cell types. Cell retention decreased from 85 to 20% as shear stress increased from 88 to 264 dynes cm⁻² (8.8 to 26 Pa). Mean spreading areas decreased after the onset of flow, but subsequently stabilized to plateau values, which were smaller at higher shear stresses. Shape factors increased faster to higher values as cells were exposed to higher shear stresses, without any obvious preference in orientation of the cells with respect to the direction of flow. Migration was unidirectional with flow and linear with time. Migration was faster for cells which had adhered for 24 h than for cells which had adhered for 3 h and was accompanied by the presence of fibrillar structures left behind on the surface upstream of migrating cells. It is concluded that after 3 h adhesion to glass, cells have adhered with an adhesion strength that does not substantially increase during the next 21 h. However, during this time changes in cell-substratum interactions seem to occur judging by the differences in, e.g., migration rates.     

豚鼠内耳前庭感觉毛细胞的分离

用机械分离法从豚鼠前庭感觉上皮中分离出不同种类的前庭感觉毛细胞（ＶＨＣ）。ＶＨＣ主要可分为Ⅰ型和Ⅱ型细胞。两种细胞形态虽有所差异，但一般均有四形或瓶形胞体，胞核位于细胞基部，胞颈和纤毛变化较大。细胞的活性可通过１％中性红染色鉴定，发现在室温下，１ｈ内大约９０％以上的分离ＶＨＣ可维持其正常形态和活性。并参照对外毛细胞形态的研究提出活性ＶＨＣ的鉴别标准。此项工作为进一步研究ＶＨＣ的感觉机制和某些疾病的发生机理打下了基础。     

首次自杀未遂者和重复自杀未遂者的对照研究

目的探讨首次自杀未遂者和重复自杀未遂者的区别.方法检查126名因自杀未遂而入院的患者,分为首次自杀未遂组和重复自杀未遂组,获得有关的临床资料并进行自杀意图及自杀企图冲动性和致死性的测定,将有关项目作对比分析.结果有51(40.5%)名重复自杀未遂者,与首次自杀未遂者比较,重复自杀未遂者已婚居多、文化程度较低、缺乏固定的经济收入、有较多的既往精神科治疗史、常饮酒、企图自杀前与他人交流少,自杀意图较低,冲动性较高(P均＜0.05).结论对伴有某些危险因素的自杀未遂者应积极进行医学干预,以期减少自杀行为的再次发生.     

Effect of ethanol on sustained attention in rats

 Acute exposure to ethanol produces deficits in sustained attention in humans, but these attentional deficits have not been modeled in animals. In this study, an operant task was used to investigate the effects of low and moderate doses of ethanol on sustained attention in rats. Performance on a two-choice reaction time task over a 1-h session was assessed immediately following administration of ethanol (0.0, 0.5, 0.75, 1.0 and 1.5 g/kg IP). Each rat was required to respond to a light stimulus of variable duration (20, 100, and 500 ms) occurring at one of two locations. Under control and saline conditions, increases in stimulus length systematically increased choice accuracy and decreased reaction time. Ethanol produced a dose-dependent decrease in choice accuracy that interacted with time, with an initial impairment that was stimulus length-dependent followed by a general vigilance decrement. The data demonstrate that ethanol impaired the ability of rats to direct and sustain attention to brief, infrequent stimuli, and provide a model for further investigations into the underlying neurobiological mechanisms for ethanol-induced attentional deficits. Received: 19 March 1996 / Final version: 30 August 1996     

1977～1990年同济医科大学新生视力状况分析

用统计学方法对14年来（1977～1990年）我校6746名新生（13492只眼）的视力状况进行分析。结果表明；新生正常视力逐年减少，视力不良率相应上升（P＜0.001）。城市学生的视力比农村学生差，男生的视力优于女生（P＜0.001）。17～19岁组的视力明显低于其他年龄组（P＜0.001）。高考分数线升高与正常视力者减少呈明显负相关；而与视力不良者增加呈正相关（P＜0.001,＜0.05）。本文认为近距离用眼持续时间过长及环境视域小等是引起视力不良的主要原因。     

Determination of needed radiographic room capacity to serve an emergency department

This study describes a method for determining the number of radiographic rooms devoted to emergency radiology that would be required to keep mean patient waiting time at a desired level. A desired mean waiting time for patients must be determined. In our setting, a mean waiting time of 8 minutes resulted in few complaints. The waiting time then sets the required utilization rate of available capacity. Daily and hourly volume and variability in volume of examinations were measured over a 3-month period. This represents the demand. The needed number of rooms is determined by comparing demand with effective available capacity for different numbers of rooms. To maintain an 8-minute mean waiting time, 50% utilization of capacity is required. Mean demand on Sundays is 176 examinations. Five rooms are required, since this gives a 180-examination effective capacity. Using waiting time as the primary decision criterion for making capacity decisions in emergency radiology has several advantages: the method is easy to use, volume variability is taken into account, and the focus is on service to patients.     

二氯胺基酚诱发的染色体畸变及染毒时间对畸变率的影响研究

２，４－二氯胺基酚（ＤＣＡＰ）是８３—１除草剂在哺乳动物体内的主要代谢产物。本研究以三种染毒计划观察了ＤＣＡＰ诱发Ｖ７９细胞的染色体畸变。结果表明：ＤＣＡＰ是一种染色体损伤剂，诱发的畸变主要为染色单体断裂和交换；３ｈ染毒和染毒后培养１７ｈ诱发的染色体畸变率最高，２０ｈ染毒观察不到染色体畸变，说明以高浓度短期染毒对高细胞毒性化合物的细胞遗传毒性研究可能是较好的染毒方案。     

Thrombin Inhibition in discordant xenograft rejection

Abstract: Microvascular thrombosis and the associated platelet and endothelial cell activation are prominent observations in xenograft rejection. This pathological picture could be related to the excessive generation of thrombin in the context of either inflammation or putative inter-species molecular incompatibilities between activated coagulation factors and their natural anticoagulants. Relatively selective thrombin Inhibition with the serine protease inhibitor SDZ MTH 958 (MTH-958) are independent of heparinoids and anti-thrombin III. MTH-958 has been shown to significantly prolong porcine cardiac function during perfusion with human blood in an ex vivo model. The aim of this study was to validate the role of thrombin generation in a rodent model of discordant xenograft rejection in vivo. The effect of thrombin inhibition with MTH-958 was tested in both hyperacute rejection (HAR) and delayed xenograft rejection (DXR) after decomplementation with cobra venom factor (CVF) in normal Lewis (Lew) rats and Intrinsic C6 deficiency In PVG (C6-/PVG) recipient rats. Recipient rats received heterotopic guinea pig cardiac xenografts and were treated with titrated doses of MTH-958 until the time of graft rejection. Plasma samples at selected time points were examined to confirm effective thrombin inhibition, and rejected grafts were analyzed by immunohistology. MTH-958 significantly improved graft survival in HAR albeit the extent of prolongation was not marked, but the agent failed to prolong survival In CVF-treated Lew rats. In C6-/PVG rats receiving MTH-958, a significantly reduced graft survival time was observed when compared with C6-/PVG controls. The grafts from MTH-958-treated animals showed dense deposits of C3, IgM, and IgG with fibrin levels similar to controls. The thrombin antagonist tested could prolong xenograft survival during HAR but had no benefit in DXR. The relative non-specificity of the serine protease inhibitor MTH-958 with the potential activation of alternative pathway of complement via the inhibition of factor I could account for the failure to prolong xenograft survival in DXR. The pathogenetic significance of thrombin generation in this situation remains to be determined by the use of more selective and pharmacologically acceptable I anti-thrombin agents.