Melittin Makes “Ion Channel” on the Membrane of Cells

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轮胎接触面对车－简支梁桥耦合振动的影响

现有分析车一桥耦合振动的研究中,都假设移动车辆与路面的接触关系为点接触．事实上,轮胎与路面是通过面接触的,通过建立新的三维车轮模型,分析了面接触对车一桥耦合振动的影响,将车轮与路面的接触面简化为长方形,通过接触面间的位移协调条件和力相互作用建立车一桥耦合振动方程,同时还研究了接触面对车一桥耦合振动的影响。     

一种改进的补丁比较模型的研究与实现

补丁比较技术可以定位程序补丁前后的差异,在漏洞发掘、病毒变种分析等领域得到了广泛的应用。以结构化比较技术为基础,建立了层次化的补丁比较模型IPCTM(Improved Patch Comparison Technique Model);改进了固定点传播算法,提出了一种针对错误匹配的修正机制;设计了控制流图重构和代码辅助匹配策略,增加了对未配对函数和基本块的补充处理。实验结果表明,IPCTM能够准确识别语义变动,消除部分非语义变动带来误差,有效减少了后续分析的工作量。     

浅析高校大学生入党动机多元化倾向

新时期高校学生党建工作面临许多新情况,提出了新课题、新挑战,对大学生入党动机多元化研究具有非常重要的现实意义。作者试着从大学生入党动机多元化倾向的归类和分析的基础上,着重就如何正确引导大学生自觉端正入党动机进行了深入探索和理论思考,提出了正确引导的有效途径。     

三角代数上的可乘同构

设T是三角代数,R′是任意环。映射φ∶T→R′称为可乘同构,指φ是双射,且满足任给a,b∈T,有φ（ab）=φ（a）φ（b）。用矩阵分块的方法证明在一个简单的条件下T到R′上的可乘同构是可加的。另外给出从T到R′上的可乘同构的一个充要条件。     

通过节点调整和约束优化近似拼接两B样条曲线

研究了两相邻B样条曲线近似拼接成1条B样条曲线的问题，基本出发点是寻找精确拼接两曲线的条件，然后通过约束优化目标，重新调整曲线的控制点以满足此条件；为了获得这样的曲线而不用多余的节点，提出了一种调整某1条后次曲线的后后个节点，且不改变其形状的新算法；同时讨论了更一般的曲线拼接问题，即让拼接曲线通过某些目标点。     

角膜缘干细胞移植治疗翼状胬肉46例分析

目的：观察角膜缘干细胞移植治疗翼状胬肉的疗效，探讨角膜缘干细胞移植术后复发率是否比传统单纯行翼状胬肉切除术复发率低。方法：对46例46眼翼状胬肉行角膜缘干细胞移植，24例24眼行单纯翼状胬肉切除术，术后定期随访，观察疗效和眼表情况。结果：角膜缘干细胞移植组平均随访11月，手术成功率97．83％，复发率2．17％；传统单纯翼状胬肉切除术组平均随访10月，手术成功率75％，复发率25％。结论：角膜缘干细胞移植手术复发率明显低于单纯翼状胬肉切除术，可替代传统手术方式治疗翼状胬肉。     

Relationship between action potential, contraction-relaxation pattern, and intracellular Ca2+ transient in cardiomyocytes of dogs with chronic heart failure

Abnormalities of contractile function have been identified in cardiomyocytes isolated from failed human hearts and from hearts of animals with experimentally induced heart failure (HF). The mechanism(s) responsible for these functional abnormalities are not fully understood. In the present study, we examined the relationship between action potential duration, pattern of contraction and relaxation, and associated intracellular Ca²⁺ transients in single cardiomyocytes isolated from the left ventricle (LV) of dogs (n = 7) with HF produced by multiple sequential intracoronary microembolizations. Comparisons were made with LV cardiomyocytes isolated from normal dogs. Action potentials were measured in isolated LV cardiomyocytes by perforated patch clamp, Ca²⁺ transients by fluo 3 probe fluorescence, and cardiomyocyte contraction and relaxation by edge movement detector. HF cardiomyocytes exhibited an abnormal pattern of contraction and relaxation characterized by an attenuated initial twitch (spike) followed by a sustained contracture ('dome') of 1 to 8 s in duration and subsequent delayed relaxation. This pattern was more prominent at low stimulation rates (58% at 0.2 Hz, n = 211, 21% at 0.5 Hz, n = 185). Measurements of Ca²⁺ transients in HF cardiomyocytes at 0.2 Hz manifested a similar spike and dome configuration. The dome phase of both the contraction/relaxation pattern and Ca²⁺ transients seen in HF cardiomyocytes coincided with a sustained plateau of the action potential. Shortening of the action potential duration by administration of saxitoxin (100 nM) or lidocaine (30 μM) reduced the duration of the dome phase of both the contraction/relaxation profile as well as that of the Ca²⁺ transient profile. An increase of stimulation rate up to 1 Hz caused shortening of the action potential and disappearance of the spike-dome profile in the majority of HF cardiomyocytes. In HF cardiomyocytes, the action potential and Ca²⁺ transient duration were not significantly different from those measured in normal cells. However, the contraction-relaxation cycle was significantly longer in HF cells (314 ± 67 ms, n = 21, vs. 221 ± 38 ms, n = 46, mean ± SD), indicating impaired excitation-contraction uncou pling in HF cardiomyocytes. The results show that, in cardiomyocytes isolated from dogs with HF, contractile abnormalities and abnormalities of intracellular Ca²⁺ transients at low stimulation rates are characterized by a spike-dome configuration. This abnormal pattern appears to result from prolongation of the action potential. Received 22 January 1998; received after revision 16 March 1998; accepted 27 March 1998     

一类有效的板弯曲单元

鉴于Ｉｒｏｎｓ的分片检验条件，在修正势能泛函中引入更一般的广义协调概念，可以推出两种简单易行的板弯曲单元。这类单元总能通过分片检验，而且可以以较少的自由度获得较高的计算精度。     

从发明先进医学设备获诺贝尔医学奖中得到的启示

百年来的诺贝尔生理或医学奖中,因发明先进的仪器设备而获诺贝尔医学奖共有四次,它们是:1924年爱因托芬(荷兰)发明了心电图机;1979年科马克(美国)亨斯菲尔德(英国)发明了电脑辅助X线断层摄影(CT);1980年内尔(德国)萨克曼(德国)发明了应用膜片钳技术;2003年比德.曼斯菲尔德(英国)和保罗.劳特布尔在核磁共振成像技术领域的突破性成就。这些先进的仪器设备的发明对人类的科学与文明的贡献是巨大的,我们从多方面可以得到深刻的启示[1]。