The association of lysophosphatidylcholine with isolated cardiac myocytes

The ability of exogenous lysophosphatidylcholine to produce electrophysiological derangements and cardiac arrhythmias in the heart has been documented. The action of lysophosphatidylcholine is thought to be mediated via its association with the membrane. The present study examined the nature of the association of lysophosphatidylcholine with isolated rat myocyte membrane. The association was studied by incubating myocytes in a lysophosphatidylcholine-containing medium. The association of lysophosphatidylcholine with the myocyte sarcolemma was not affected by palmitic acid and glycerophosphocholine but was reduced by platelet-activating factor (PAF). The addition of albumin (5 mg/mL) at the end of the incubation period effectively removed the lysophosphatidylcholine from the myocytes. Our results suggest that most of the lysophosphatidylcholine in isolated myocytes was associated preferentially with the outer leaflet of the myocyte sarcolemma. This type of association might be responsible for the lysophosphatidylcholine-induced electrophysiological alterations in the heart.     

RS-485在电表中的应用

本文讨论了使用RS-485设计电表通讯电路的一些最优设计方案。参照IEC 61036和DL/T645等相关标准,本文还讨论了元件选择和性能折衷问题并提供了一些参考设计细节。     

差动信号最佳实践

差动信号用于以太网、RS-485、控制器局域网络(CAN)、USB等的抗扰。在理想情况下,应抑制所有共模噪声。在现实应用中,需要考虑一些设计方法和组件参数,以保持数据流的高可信度。差动信号用于大多数接口中,通过线缆传送数字信息。和单端信号相比,差动信号虽然要求使用两条信号线而非一条,但差动信号拥有更高的抗扰性能。     

Lysophosphatidylcholine accumulation in the ischemic canine heart

The production of cardiac arrhythmias and the elevation of lysophosphatidylcholine level in the ischemic myocardium have been well-documented in a number of studies. However, the relationship between the production arrhythmias and the elevation of tissue lysophosphatidylcholine level was not reported. In this study, the lysophosphatidylcholine level and the occurrence of cardiac arrhythmias in the ischemic canine heart were monitored. A temporal relationship between the accumulation of lysophosphatidylcholine and the occurrence of arrhythmias was established after five hr of ischemia. A significant elevation of lysophosphatidylcholine was detected at three hr of ischemia without the occurrence of arrhythmias. The results indicate that cardiac arrhythmias did not cause the elevation of lysophosphatidylcholine and if lysophospholipids are causally related to the arrhythmias that a critical level of the lysophospholipid must accumulate in order to elicit electrophysiological alterations.     

Population densities of Sulawesi crested black macaques (Macaca nigra) on Bacan and Sulawesi, Indonesia: effects of habitat disturbance and hunting

Population surveys of Sulawesi crested black macaques (Macaca nigra) were conducted on the Indonesian islands of Sulawesi and Bacan in 1992-1994 to assess the status of natural populations and determine habitat and anthropogenic factors affecting their population densities. We surveyed five sites for primates, including undisturbed and disturbed habitats. Data were collected on habitat structure and composition at two undisturbed and one disturbed forest site in which the primates were surveyed. The highest density of macaques was found in primary forest at Gunung Sibela Nature Reserve on Bacan (170.3 individuals/km2). Population density in logged forest on Bacan was high but significantly less than primary forest (133.4 individuals/km2). The high density of crested black macaques in primary forest on Bacan is best explained by the high carrying capacity found in primary forest. The lower food quantity and quality of food resources found in logged forest correlated with lower primate densities compared to primary forest. However, the large population of macaques in logged forest demonstrates the conservation value of such forest. Densities on Sulawesi at Tangkoko-Batuangas-DuaSudara Nature Reserve (TBDS) showed a continuing decline since earlier surveys. Primate densities were highest near the protected center of Tangkoko Reserve (66.7 individuals/km2). The peripheral areas of Batuangas and DuaSudara, even though adjacent and continuous, showed lower population densities of 46.4 and 23.5 individuals/km2, respectively. The best explanation for the continued decline of Macaca nigra populations at TBDS is hunting. Unless conservation measures are implemented immediately, M. nigra on Sulawesi risks extinction in the near future.     

设计用于自动化的工业现场总线网络

引言 为应用选择总线网络时至少存在两种情况.一种情况是,工程师从一张白纸入手,可以设计出任何能够最好满足当前应用需求的网络.     

将RS-485用于数字发动机控制应用

Ⅰ.简介 数字发动机控制采用数字处理器来控制电动机的运转。一般情况下数字处理器可采用一种或多种反馈方式,使其构成一个闭环系统。这可比作模拟控制系统和开环传动系统。 许多应用都采用了数字发动机控制,包括存储设备(如:磁盘驱动器)、工业机器人、高精度半导体制造、打印机以及复印机等。     

Changes and continuities in a Mediterranean landscape: a new interdisciplinary approach to understanding historic character in western Catalonia

To understand why historic landscapes changed in the past researchers need to identify when and where changes took place, but in rural landscapes, the origins and development of many historic elements including field systems, roads, terraces and other earthworks remain poorly understood. This paper outlines a practical interdisciplinary method using GIS-based historic landscape characterisation (HLC) to integrate data from different sources and model how historic character varies in space. It pilots an innovative approach using luminescence profiling and dating that can underpin the HLC with significantly improved knowledge of historic processes of change. We focus on four case studies of terraced agricultural landscapes in western Catalonia and demonstrate for the first time that existing terrace systems often have medieval or early modern origins.     

Adaptive fuzzy process control of integrated circuit wire bonding

One step in the assembly of integrated circuits is wire bonding, requiring expert knowledge to optimize critical process characteristics. This paper describes a fuzzy logic controller which sets parameters for the wire bonding process for gold ball wire bonds, specifically controlling bonded ball diameter and shear strength density. While the focus is on control of ball bonds, the method is general and may be applied to other bonding methods with minor modifications. The design of the fuzzy engine and the development of rules based on both operator experience and textual sources are discussed. An adaptation technique is developed to tune the controller's membership functions based on the measured results of the process. The controller has been tested on actual devices in an industrial setting; results show improved process control in terms of consistency and reduced operator adjustment