Transcytosis of alpha1-acidic glycoprotein in the continuous microvascular endothelium

By using perfusions and bolus administration, coupled with postembedding immunocytochemical procedures, we have identified the structures involved in the transport of derivatized orosomucoid (alpha1-acidic glycoprotein) across the continuous microvascular endothelium of the murine myocardium. Our findings indicate that: (i) monomeric orosomucoid binds to the luminal surface of the endothelium; (ii) it is restricted to caveolae during its transport across the endothelium; (iii) it is detected in the perivascular spaces at early time points (by 1 min) and in larger quantities at later time points (>5 min) from the beginning of its perfusion or its intravascular administration; (iv) no orosomucoid molecules are found in the intercellular junctions or at the abluminal exits of interendothelial spaces; and (v) the vesicular transport of orosomucoid is strongly inhibited by N-ethylmaleimide (>80%). Because, by size and shape, the orosomucoid qualifies as a preferential probe for the postulated small pore system, our results are discussed in relation to the pore theory of capillary permeability.     

Neuronal units linked to microvascular modules in cerebral cortex: response elements for imaging the brain

How neuronal activity changes cerebral blood flow is of biological and practical importance. The rodent whisker-barrel system has special merits as a model for studies of changes in local cerebral blood flow (LCBF). Stimulus-evoked changes in neural firing and 'intrinsic signals' recorded through a cranial window were used to define regions of interest for repeated flow measurements. Whisker-activated changes in flow were measured with intravascular markers at the pia. LCBF changes were always prompt and localized over the appropriate barrel. Stimulus-related changes in parenchymal flow monitored continuously with H2 electrodes recorded short latency flow changes initiated in middle cortical layers. Activation that increased flow to particular barrels often led to reduced flow to adjacent cortex. Dye was injected into single penetrating arterioles from the pia of the fixed brain and injected into arterioles in slices of cortex where barrels were evident without stains. Arteriolar and venular domains at the surface were not directly related to underlying barrels. Capillary tufts in layer IV were mainly coincident with barrels. The matching between a capillary plexus (a vascular module) and a barrel (a functional neuronal unit) is a spatial organization of neurons and blood vessels that optimizes local interactions between the two. The paths of communication probably include: neurons to neurons, neurons to glia, neurons to vessels, glia to vessels, vessels to vessels and vessels to brain. Matching a functional grouping of neurons with a vascular module is an elegant means of reducing the risk of embarrassment for energy-expensive neuronal activity (ion pumping) while minimizing energy spent for delivery of the energy (cardiac output). For imaging studies this organization sets biological limits to spatial, temporal and magnitude resolution. Reduced flow to nearby inactive cortex enhances local differences.     

微量Si在W—7Ni—3Fe重合金中的行为

研究了掺到原料Ｗ粉中微量Ｓｉ（４００ｐｐｍ）在Ｗ－７Ｎｉ－３Ｆｅ重合金中的分布及在液相烧结过程中的行为。结果表明，Ｓｉ主要以固溶形式分布在Ｗ晶粒中。Ｘ射线光电子能谱（ＸＰＳ）分析发现，在掺杂Ｓｉ的Ｗ－Ｗ及Ｗ－基体相界面富集ＳｉＯ２和Ｎａ２ＳｉＯ３在未掺杂试样的断口表面发现了较弱的ＷＯ２的ＸＰＳ谱，而在掺杂合金中未发现ＷＯ２。     

Endotoxin-induced platelet aggregation in heparinised equine whole blood in vitro

Endotoxaemia is a leading cause of death among horses. Thrombocytopenia is a common finding in clinical and experimentally-induced cases of endotoxaemia and can lead to coagulopathies, including disseminated intravascular coagulopathy which is usually fatal. In this study it was shown that endotoxin (3 ng ml-1 to 25 micrograms ml-1) can aggregate equine platelets in heparinised whole blood in vitro. The endotoxin-induced aggregation (EIA) was shown to be dependent on the presence of leucocytes in the blood and did not occur when detoxified endotoxin was used, suggesting that lipid A was necessary for the response. Aspirin (1 mmol litre-1) had no effect on EIA whereas apyrase (40 micrograms ml-1) completely abolished it and CV3988 (3 to 30 mumol litre-1) (a competitive antagonist of platelet-activating factor) inhibited the response in a concentration-dependent manner. It is concluded that endotoxin activates equine platelets at low concentrations through an indirect mechanism that involves calcium, leucocytes, adenine nucleotides and platelet-activating factor.     

游艇概念设计方法与技术研究

针对游艇的概念设计方法与技术展开研究,从创意设计思维层面入手,建立了游艇设计概念引入、意象及内涵深化的设计创意库,包括海洋生物库、东方文化符号库、其它类产品创意库等三大类;分析了游艇概念设计从抽象到具体的过程,提出了游艇创意概念设计的底影套模法;探讨了游艇设计的参数化、模块化实现技术。     

多输入的二阶广义分布参数系统的控制综合问题

广义分布参数系统具有广泛的实际背景.如复合材料中的温度分布,电缆中的信号传播,电磁耦合超导线路中的电压分布,飞行器姿态控制等问题研究中都会出现这样的系统.极点配置与反馈稳定性是这类系统研究的重要方面.本文应用泛函分析及算子理论讨论了Hilbert空间中多输入的二阶广义分布参数系统的极点配置与反馈稳定性问题,获得了这类系统极点可配置与可镇定的一些充分条件,并利用复分析、复级数、有界线性算子的广义逆等方法建立了反馈控制律的构造性表达式.本文结论不仅具有重要的实际意义,而且对广义分布参数系统的控制综合问题研究具有重要的理论价值.     

双余度DSP数据采集装置在某型控制器中的应用

针对某型控制器设计的双余度DSP数据采集装置,采用以双端口RAM方式进行数据交换。结果表明,此数据采集装置既能快速完成模拟数据的采样,又能快速地在DSP间进行高速数据交换,同时,还能够满足基于DSP数据采集装置的高精度与小型化要求。     

基于虚拟组织的桌面云安全访问与共享机制研究

采用云计算技术实现托管式的虚拟桌面一般被称为桌面云。近年来桌面云被认为是云计算最为成熟的应用之一,本文着重研究桌面云安全访问与共享机制。我们使用基于PKI的证书认证建立了虚拟组织,在其上重点研究了虚拟机的创建,远程桌面访问,共享等应用。证书认证等机制可以使得访问更加安全可靠。而通过虚拟组织的信任关系,多个用户可以共享同一个虚拟机。为了确保远程通道的安全,我们采用了OpenVPN来构建虚拟专用网络,对虚拟机的使用者进行认证并对通信进行加密保护。     

无线传感网络覆盖中概率Voronoi模型及算法研究

覆盖是无线传感网络中最重要的问题之一,随机覆盖是目前研究的主流。基于Voronoi图的随机覆盖算法是无线传感网络领域的研究热点。目前研究中采用的Voronoi图,主要采用基于距离的Voronoi边赋权值模型,存在两个主要问题,即模型粗糙和监测节点不全。以实测的分段概率传感模型为基础,从多传感协同监测的角度构造一种概率Voronoi模型,试图解决以上问题。并且用基于概率Voronoi模型的最大突破路径算法验证了模型有效性。就掌握的文献来看,该模型是首次提出,具有较好的实用推广价值。