Vascular endothelial growth factor (VEGF) induces rapid prourokinase (pro-uPA) activation on the surface of endothelial cells

Vascular endothelial growth factor (VEGF) is the pivotal angiogenic growth factor activating endothelial cells to migrate, proliferate, and form capillary tubes. For an ordered endothelial cell migration, tissue invasion, and degradation of the extracellular matrix, proteolytic machinery is indispensable. Such machinery, suitable for localized proteolysis, is provided by the prourokinase-urokinase-plasmin system. Prourokinase (pro-uPA), the initial component of this system, is, however, synthesized in its inactive precursor form and as such bound to its cellular receptor uPAR. Here we identify a mechanism via which VEGF(165) interacting with its receptor VEGFR-2 rapidly induces prourokinase activation that is dependent on a change in integrin affinity, activation of matrix metalloproteinase 2 (MMP-2), and pro-uPA being bound to its surface receptor uPAR. This VEGF-induced pro-uPA activation on endothelial cells is responsible for VEGF-dependent local fibrinolytic activity and might be one of the initial steps in the angiogenic process.     

Delay-dependent criteria for robust stability of time-varying delay systems

This paper deals with the problem of delay-dependent robust stability for systems with time-varying structured uncertainties and time-varying delays. Some new delay-dependent stability criteria are devised by taking the relationship between the terms in the Leibniz-Newton formula into account. Since free weighting matrices are used to express this relationship and since appropriate ones are selected by means of linear matrix inequalities, the new criteria are less conservative than existing ones. Numerical examples suggest that the proposed criteria are effective and are an improvement over previous ones.     

Licorice-induced hypertension and syndromes of apparent mineralocorticoid excess

Excessive ingestion of licorice induces a syndrome of hypokalemia and hypertension that reflects increased activation of renal mineralocorticoid receptors by cortisol. A similar syndrome of cortisol-dependent mineralocorticoid excess occurs in congenital deficiency of the enzyme 11 beta-hydroxysteroid dehydrogenase, which normally inactivates cortisol to cortisone. It has been shown that licorice inhibits 11 beta-dehydrogenase, preventing local inactivation of cortisol and allowing cortisol inappropriate access to intrinsically nonspecific renal mineralocorticoid receptors. Further studies with licorice and its derivatives have revealed a widespread role for 11 beta-dehydrogenase in regulating tissue sensitivity to cortisol. Deficient 11 beta-dehydrogenase activity provides a novel pathogenetic mechanism for hypertension, and current research suggests that several common forms of hypertension can be explained by the mechanisms that operate in licorice-induced hypertension.     

一种结合数据融合与树状小波的鲁棒数字水印算法

利用树状小波分解结合人类视觉系统(HVS)的特性,提出一种基于数据融合的鲁棒性数字水印算法,向载体图像中自适应的嵌入多个数字水印副本;在提取水印时,在每个块中使用独立分量分析ICA的方法提取水印,并对提取出的多个水印副本图像进行融合操作,以提高水印的鲁棒性.仿真试验表明了该方法的有效性,嵌入的水印具有较高的透明性,同时对常见图像处理攻击有很强的鲁棒性.     

基于单片机的无线测温系统设计

利用短距离无线通信技术构成一个基于单片机的简易、低功耗的无线多点温度测量系统。系统以AT89C2051、AT89C51单片机为核心,采用数字式温度传感器DS18B20、无线收发芯片nRF24L01实现了温度的采集、控制、无线收发等,给出了系统硬件及软件的具体设计思想与实现方法。     

一种适合Underlay认知无线传感网络的跨层路由算法

在Underlay认知无线传感网络（Underlay Cognitive Radio Sensor Network,Underlay CRSN）中,由于每个信道被主用户所使用的状态随机变化,设计路由算法不仅需要考虑网络中节点的能量消耗以及延长网络寿命的需求,还要考虑路由路径上各链路的信道选择策略对路径数据传输可靠性的影响。该文研究了Underlay认知无线电模型下的CRSN路由问题,提出了一种适合该路由问题的链路Utility函数,并将这类问题建模为以最小化Utility为目标的最优化问题。在讨论了几种传统的无线传感器网络（Wireless Sensor Network,WSN）路由算法之后,提出了一种适合Underlay CRSN的跨层路由算法,并给出了该算法的分布式实现方案。计算机仿真表明所提出的路由算法能很好地适应UnderlayCRSN中信道可用状态的随机变化。     

Delay-dependent robust stability criteria for uncertain neutral systems with mixed delays

This paper concerns the problem of the delay-dependent robust stability of neutral systems with mixed delays and time-varying structured uncertainties. A new method based on linear matrix inequalities is presented that makes it easy to calculate both the upper stability bounds on the delays and the free weighting matrices. Since the criteria take the sizes of the neutral- and discrete-delays into account, it is less conservative than previous methods. Numerical examples illustrate both the improvement this approach provides over previous methods and the reciprocal influences between the neutral- and discrete-delays.     

基于SaaS模式的电子政务架构研究

SaaS模式作为云计算的一种形式,在互联网技术的发展和应用软件成熟的基础上,成为一种创新的软件应用模式。如何保证系统安全与设计高效安全的数据架构是决定SaaS应用成败的关键问题。本文将以基于SaaS的政务系统为业务依托,以数据库设计和系统安全、SoA为理论基础,提出STEG解决方案。此解决方案在SaaS软件中能很好的解决数据建模、系统安全和软件架构方面的问题,对SaaS下的软件研究具有深刻借鉴意义。     

Singularity‐avoiding swing‐up control for underactuated three‐link gymnast robot using virtual coupling between control torques

An underactuated three‐link gymnast robot (UTGR) is a simple model of a gymnast on a high bar. The control objective of a UTGR is to swing it up from a point near the straight‐down position and to stabilize it at the straight‐up position. To achieve this, we first divide the motion space into two subspaces, swing‐up area and balancing area, and design a controller for each. The design of a swing‐up control law that ensures that the UTGR enters the balancing area is crucial because the UTGR is subject to a nonholonomic constraint and is highly nonlinear during the swing‐up motion. This study focused on how to design a swing‐up control law that contains no singularities. The key concept is the introduction of a virtual coupling between control torques, which converts the problem of avoiding singularities to one of imposing constraints on the parameters of the control law and properly selecting those parameters. A swing‐up control law thus designed ensures that the UTGR enters the balancing area in a natural stretched‐out posture. This makes it easy to stabilize the UTGR in the balancing area. Copyright © 2013 John Wiley & Sons, Ltd.