Mechanical stretch induces hypertrophic responses in cardiac myocytes of angiotensin II type 1a receptor knockout mice

Many lines of evidence have suggested that angiotensin II (AngII) plays an important role in the development of cardiac hypertrophy through AngII type 1 receptor (AT1). To determine whether AngII is indispensable for the development of mechanical stress-induced cardiac hypertrophy, we examined the activity of mitogen-activated protein kinase (MAPK) family and the expression of the c-fos gene as hypertrophic responses after stretching cultured cardiac myocytes of AT1a knockout (KO) mice. When cardiac myocytes were stretched by 20% for 10 min, extracellular signal-regulated protein kinases (ERKs) were strongly activated in KO cardiomyocytes as well as wild type (WT) myocytes. Both basal and stimulated levels of ERKs were higher in cardiomyocytes of KO mice than in those of WT mice. Activation of another member of the MAPK family, p38(MAPK), and expression of the c-fos gene were also induced by stretching cardiac myocytes of both types of mice. An AT1 antagonist attenuated stretch-induced activation of ERKs in WT cardiomyocytes but not in KO cardiomyocytes. Down-regulation of protein kinase C inhibited stretch-induced ERK activation in WT cardiomyocytes, whereas a broad spectrum tyrosine kinase inhibitor (genistein) and selective inhibitors of epidermal growth factor receptor (tyrphostin, AG1478, and B42) suppressed stretch-induced activation of ERKs in KO cardiac myocytes. Epidermal growth factor receptor was phosphorylated at tyrosine residues by stretching cardiac myocytes of KO mice. These results suggest that mechanical stretch could evoke hypertrophic responses in cardiac myocytes that lack the AT1 signaling pathway possibly through tyrosine kinase activation.     

程控交换机收号系统模拟的研究

本文提出了一种模拟程控交换机收号系统的有效方法,采用消息驱动收号事件表的思想,运用并发控制技术,实现了在没有话路硬设备的条件下多用户同时拨号在线模拟收号控制的功能。本文提出的收号系统模拟方案已成功应用于某国产中大容量程控交换机的呼叫模拟系统中。     

网络环境下计算机信息安全分析

随着网络信息技术的不断发展,人们对于网络信息的需求与依赖性逐渐增强。然而,网络在带给人们便利的同时,也带来了很多的不安全因素,主要表现在信息泄露、信息篡改、非法占有网络信息与网络资源等。因计算机信息安全隐患的存在,个人、企业遭受"攻击"的计算机信息安全事件时有发生,并造成了巨大的经济损失。因此,加强网络环境下的计算机信息安全管理工作就显得很有必要。本文就网络环境下计算机信息安全问题展开探讨。     

带缓变参数的广义系统的弱稳定性*

本文利用“冻结系数法”讨论了带缓变参数的广义系统的稳定性,提出了所谓弱稳定性的概念,得出了广义系统弱稳定的充分条件,并将结果推广到了一类非线性情形。     

An online multiple object tracker based on structure keeper net

We propose a novel online multiple object tracker taking structure information into account. State-of-the-art multi-object tracking (MOT) approaches commonly focus on discriminative appearance features, while neglect in different levels structure information and the core of data association. Addressing this, we design a new tracker fully exploiting structure information and encoding such information into the cost function of the graph matching model. Firstly, a new measurement is proposed to compare the structure similarity of two graphs whose nodes are equal. With this measurement, we define a complete matching which performs association in high efficiency. Secondly, for incomplete matching scenarios, a structure keeper net (SKnet) is designed to adaptively establish the graph for matching. Finally, we conduct extensive experiments on benchmarks including MOT2015 and MOT17. The results demonstrate the competitiveness and practicability of our tracker.

     

Feature Extraction Using a Complete Kernel Extension of Supervised Graph Embedding

In this article, the kernel-based methods explained by a graph embedding framework are analyzed and their nature is revealed, i.e. any kernel-based method in a graph embedding framework is equivalent to kernel principal component analysis plus its corresponding linear one. Based on this result, the authors propose a complete kernel-based algorithms framework. Any algorithm in our framework makes full use of two kinds of discriminant information, irregular and regular. The proposed algorithms framework is tested and evaluated using the ORL, Yale and FERET face databases. The experiment results demonstrate the effectiveness of our proposed algorithms framework.     

The modeling and implementation of tri-rotor flying robot

The objective of this study is to develop a tri-rotor flying robot, which adopts the Y-shaped three-rotor structure. In order to balance the yaw torque produced by the three rotors, the RC servomotor and linkage is installed on the tail axis in order to improve the angle of the rolling axis of the tail motor. Moreover, through the torque generated by the horizontal component of the lift from the inclined motor on the tail axis, it balances the yaw torque of the three rotors. The dynamic equations of the tri-rotor flying robot are determined in this paper. The relationship between motor thrust, angular acceleration, and voltage input was also studied in this research. In order to study the effect of control parameters on the flight stability completely, this study develops a universal stability experimental platform to help tuning the control parameters safely. Based on this, the tri-rotor flying robot can rapidly change flying gesture and avoid oscillation. Finally, we conducted some indoor and outdoor flight tests. From the experimental results, the tri-rotor flying robot can fly and hover stably in the sky.     

Sensitizing Effect of Mixed Surfactants on the Colouration of Scandium(Ⅲ)with Phenylfluorone or Its Derivatives

In the presence of mixed micelle of a cationic and a nonionic surfactants,the reaction of scandium(Ⅲ)with phenylfluorone or its derivatives results in a very sensitive colouration:furthermore this chromophoricsystem tolerates the existence of a considerable amount of masking agents,so that many interfering ions can bemasked and its selectivity would be further improved.After studying the optimum conditions and main charac-ters of some similar systems,the system of Sc(Ⅲ)—Orthonitrophenyuorone—CetyltrimethylammoniumBromide(CTMAB)—Triton X-200 is chosen for the spectrophotometric determination of microamount ofscandium.The proposed method shows not only high sensitivity(with a molar absorptivity of 2.12×1~sLmol~(-1)·cm~(-1))and selectivity,but also high tolerance of chromophoric conditions.Beer's law is obeyed over arange of 0～6.0 μg Sc/25ml.If the dual-wavelength method is applied,a much higher molar absorptivity o|"3.04×10~5L·mol~(-1)·cm~(-1)than those of other systems ever reported in the literatures can be attained:more-over.its linear range is extended to 0～8.0 μg Sc/25ml and its reproducibility is also improved.     

以1,3-二(4-邻羟基苯亚胺次甲基)苯氧基丙烷为载体的铁离子(Ⅲ)电极的研究

以1,3-二(4-邻羟基苯亚胺次甲基)苯氧基丙烷为中性载体制备了PVC膜Fe3+离子选择性电极。该电极对Fe3+呈现出良好的选择性和近Nernst电位响应性能。电极斜率为21mV/dec,线性范围为3.0×10-5～1.0×10-1mol/L,检出限为1.0×10-5mol/L。采用交流阻抗技术研究了电极的响应机理,并将电极作为指示电极初步用于EDTA的电位滴定。     

基于信息化的地表水水质预测

水利信息化技术指在水质信息管理、水质分析评价、水质预测和抗洪救灾等方面提供了多重应用需求;本文针对目前主流的计算机技术,对地表水常见水质预测方法进行分析与探索。