Autonomic nervous activity at episodes of myocardial ischemia in patients with coronary artery disease by heart rate power spectral analysis

Heart rate power spectral analysis in 44 patients with coronary artery disease was obtained from 24-hour dynamic electrocardiogram. 195 episodes of transient myocardial ischemia that was defined as horizontal or down sloping depression of the ST segment of > or = 0.1 mV and lasted for > or = 2 minutes were studied. The area of low frequency components (LF, 0.02-0.10 Hz) representing predominontly sympathetic tone with some contribution from the parasympathetic tone and that of high frequency components (HF, 0.15-0.40 Hz) representing mainly parasympathetic tone and the value of LF/HF on 4 minute heart rate power spectral graph at the deepest depression of ST segment were compared with that before the episode of myocardial ischemia. The area of HF of fast rate myocardial ischemia occurring in night reduces significantly (P < 0.001), the value of LF/HF increases markedly (P < 0.05) and the area of LF increases slightly. The results suggest that there is a change of autonomic nervous activity during the episode of fast rate myocardial ischemia in night, parasympathetic nervous tone decreases markedly, there may be secondary increase of sympathetic nervous activity.     

厚度伸缩压电陶瓷振子

对厚度伸缩压电陶瓷振子的振动状态进行了分析,并得到其等效电路.推导了振子的谐振频率、反谐振频率以及等效电路参数与振子尺寸、振子材料的介电、压电、弹性常数间的关系式.最后讨论了振子的一些特性和制作.     

Biochemical genetic studies on wild populations of the Vicia amoena complex (tribe Vicieae: Fabaceae)

A 45-year-old human immunodeficiency virus (HIV)-infected patient has suffered for a period of 4 years from recurrent and, later on, persistent oral pseudomembranous candidosis. The Candida isolates proved to be resistant to azole derivates in vitro and in vivo. Treatment with amphotericin B parenterally was successful in February 1996, but had to be stopped when chemotherapy for lymphoma was started. In August 1996, the patient showed a shift from the pseudomembranous to the erythematous type of oral candidosis; antiretroviral combination therapy including the HIV protease inhibitor saquinavir had been started 4 months previously. In July 1997, the patient was still suffering from a persistent oral candidosis of the erythematous type.     

Shifting physician prescribing to a preferred histamine-2-receptor antagonist. Effects of a multifactorial intervention in a mixed-model health maintenance organization

Three receptor tyrosine kinases of the PDGF receptor family (RTKP) that clustered within 1000 Kb of the mouse chromosome 5 constitute an interesting unit that are expressed in three distinct cell lineages essential for constructing hematopoietic tissues. Namely, the c-kit gene that is expressed in hematopoietic stem cells is flanked by pdgfr alpha and flk genes expressed respectively in stromal cells and vascular endothelial cells. In this article, we review our results on their expression in the embryonic hematopoietic tissues. We found that co-expression of Flkl and c-Kit was frequently detected either in vascular endothelial cells or hematopoietic cells in the early hematopoietic tissues. On the other hand, the three RTKPs are expressed in different cell lineages in the fetal liver. On the basis of this finding, we propose two modes of embryonic hematopoiesis; hematogenic angiopoiesis and hematopoiesis.     

改善准分子激光光强分布的一种方法

介绍了一种改善准分子激光输出光束光强均匀性的新方法，给出了实验结果和简要的分析。     

折线链节点标注技术

针对传统多边形位置关系计算比较烦琐,以及简单多边形的理论难以拓展到一般多边形的问题,提出标注节点状态的方法.通过定义11种位置来描述折线链上每个节点的状态,再采用"线段端点与线段"和"线段端点与邻折线"的标注方法来实现任意折线链的标注,同时利用两线段分割预处理使相交仅发生在端点处,从而使算法更高效;然后给出折线链基本位置关系的节点特征,并且探讨了三维顶点的标注方法.该方法的标注原理简单、方法实用,算法空间和时间复杂度分别为O(n)和O(n2).实验结果表明,该方法对任意形状的折线链都能实现稳定标注;通过搜索节点状态特征可以求解折线链间的相互关系,还可以实现一般折线链的碰撞检测、相交区域计算以及多边形简单化分解等.     

基于区间树硬件加速索引的Marching Cubes算法

为了充分利用GPU的海量线程并行架构,提高等值面可视化效率,提出一种基于区间树硬件加速索引的Marching Cubes算法.该算法在预计算阶段利用GPU构造多区域的区间树作为体数据体素的值域索引;在实时运行阶段根据用户给定的阈值,通过该索引并行地搜索活跃体素,并生成活跃体素的多级索引,然后分配线程处理活跃体素,抽取并绘制等值面.将文中算法应用到不同体数据上的实验结果表明,其能够显著地提高现有Marching Cubes算法的效率;与现有的GPU基准算法相比,最高能达到4～10倍的加速比.     

MEMS惯性传感器ADIS16355在姿态测量中的应用

设计了基于微电子机械系统(Microelectro mechanical system,MEMS)惯性传感器集成模块ADIS16355的姿态测量系统。该姿态测量系统采用ADIS16355作为惯性测量单元,利用加速度计对重力向量的观测来修正陀螺给出的姿态信息,卡尔曼滤波实现传感器信息融合以计算运动载体的姿态角。介绍了ADIS16355的基本功能模块,阐述了两种传感器融合测量实时姿态角的方法并给出了卡尔曼滤波算法迭代过程。基于ARMv7架构的Cotex-M3微处理器设计了姿态测量系统硬件。采用AHRS500GA对该姿态测量系统性能进行了测量姿态角的验证实验。测试结果表明,该姿态测量系统能在动态条件下准确地测定运动物体实时姿态角,其误差一般在±1°左右。