Some sufficient conditions for global exponential stability of delayed Hopfield neural networks.

In this paper, we have derived some sufficient conditions for existence and uniqueness of equilibrium and global exponential stability in delayed Hopfield neural networks by using a different approach from the usually used one where the existence, uniqueness of equilibrium and stability are proved in two separate steps, rather we first prove global exponential convergence to 0 of the difference between any two solutions of the original neural networks, the existence and uniqueness of equilibrium is the direct results of this procedure. We obtain the conditions by suitable construction of Lyapunov functionals and estimation of derivates of the Lyapunov functionals by the well-known Young's inequality and Holder's inequality. The proposed conditions are related to p-norms of vector or matrix, p in [1, infinity] and thus unify and generalize some results in the literature.     

离子通道与弱精子症

弱精子症是引起男性不育的常见病因之一。随着以精子自身为对象的研究深入,发现离子跨膜转运对精子的生理活动起着重要的作用。离子通道病于20世纪90年代提出,现已逐渐发现临床上许多先天性和/或后天获得性疾病与异常的离子通道有关。因此,关于精子的生理和疾病与离子通道的关系研究逐渐成为当前研究的热点之一。现就近年来与精子运动相关的离子通道,包括阳离子通道和阴离子通道的研究进展作一综述。     

B组轮状病毒WH-2株vp7基因的原核表达与抗体的制备

目的：在大肠杆菌中表达人B组轮状病毒WH-2株VP7蛋白并制备其兔抗血清。方法：根据B组轮状病毒（GBRV）WH-2株vp7基因的全序列设计引物,用PCR的方法扩增得到vp7基因的编码区。将其克隆到原核GST融合表达载体pGEX-KG内,转化大肠杆菌E.coliDH5α,IPTG诱导表达人B组轮状病毒WH-2株VP7蛋白,经SDS-PAGE分离纯化表达的蛋白免疫新西兰兔,制备人B组轮状病毒WH-2株VP7蛋白抗血清。结果：经鉴定确认,vp7基因以正确的方式插入到载体中,此重组表达载体经IPTG诱导后,可表达相对分子量为53.4 kDa的GST-VP7融合蛋白。制备的抗血清经同样诱导表达的表达载体pGEX-KG表达产物吸收后1：500倍稀释后用Western Blot分析,与53.4 kDa的GST-VP7融合蛋白获得特异性显色信号。结论：人B组轮状病毒WH-2株VP7蛋白成功在大肠杆菌中GST融合表达,所表达的蛋白和制备的抗体不但为研究结构与功能提供了物质基础,也为GBRV所引起的疾病预防、诊断和治疗等流行病学研究和临床诊断奠定了基础,具有重要实际应用价值。     

持续压力超负荷对兔左心室细胞凋亡的影响

OBJECTIVE: To study the effect of chronic pressure overload on the apoptosis of the left ventricle myocytes in rabbits. METHODS: Rabbit models of chronic pressure overload-induced heart failure were prepared in which dynamic changes of apoptotic myocytes in the left ventricle were observed by way of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. RESULTS: Only a few apoptotic cells was observed in the sham-operated group, while in the experimental group, the apoptotic left ventricle myocytes significantly increased after operation, presenting a peak level between day 3 and day 7. Seven days after the operation, the apoptotic myocytes began to decrease and till day 14, the apoptotic cell number had been smaller than that measured on day 1. When signs of heart failure set in, the apoptotic myocytes were again increased (P<0.001). CONCLUSION: During chronic pressure overload, myocyte apoptosis in the left ventricle is elevated at the early stages and undulates subsequently, with the peak occurring before hypertrophy is obvious.     

高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数

本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4～5.6%,血浓69.6～1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。     

DICOM通讯程序的设计

本文在研究DICOM协议的基础上，介绍了DICOM通讯的消息结构；从设计出发，分析了DICOM通讯过程的各个技术环节。     

安氟醚吸入与预注爱肌松对其肌松时效的影响

单次静注爱肌松（０．３ｍｇ·ｋｇ－１，对照组）于３．１７±０．８１分钟（ｘ±ｓ）可获得满意的气管插管条件。预注组（１０例）首次量０．２７ｍｇ·ｋｇ－１于预注剂量（０．０３ｍｇ·ｋｇ－１）后５分钟给予，可使爱肌松的起效时间缩短至０．９３±０．１７分钟（Ｐ＜０．００１），ＴＯＦ无反应期、２５％和９０％恢复时间两组无显著差别（Ｐ＞０．２５）。全部病例均获得了良好的气管插管条件，预注的优点还在于能评估患者对所选用非去极化肌松药的敏感性。预往后ＴＯＦ肌电图Ｔ１抑制＞１０％较无明显ＴＯＦ抑制者肌松恢复时间显著延长（Ｐ＜０．０５）。同时发现吸入安氟醚可使爱肌松作用时效延长。