Coordinated induction of plasminogen activator inhibitor-1 (PAI-1) and inhibition of plasminogen activator gene expression by hypoxia promotes pulmonary vascular fibrin deposition

PURPOSE: In a rabbit model, transposition of a muscle pedicle flap to an ischemic hind limb has been shown to result in the development of new blood vessels that connect the arterial circulation of the flap to the circulation of the limb. The hypothesis that exogenous recombinant basic fibroblast growth factor (bFGF) would enhance the development of this new blood supply was examined and the regulation of bFGF in this process was investigated. METHODS: The right common iliac artery was ligated in 12 male New Zealand white rabbits. An abdominal wall muscle flap based on the left inferior epigastric artery was transposed to the right thigh. bFGF in phosphate-buffered saline (PBS) at 3 ng/h (n = 6), or PBS alone (n = 6), was infused for 7 days via mini-osmotic pumps with an infusion catheter positioned at the flap-muscle interface. The flap-muscle interface was immunostained with anti-alpha-actin antibody to determine blood vessel density (number of vessels/mm) and with anti-bFGF antibody to evaluate bFGF distribution. RNA was isolated from these sections, and polymerase chain reaction (PCR) was used to examine endogenous bFGF messenger RNA (mRNA) expression. RESULTS: Blood vessel density was significantly increased in animals receiving exogenous bFGF (22. 0 +/- 10.6 vessels/mm vs. 10.7 +/- 8.8 vessels/mm, P =.009). In the controls, neovessels were arranged in clusters with endogenous bFGF concentrated around these clusters. In bFGF-treated animals, vessels were diffusely scattered throughout the flap-limb interface, corresponding to the distribution pattern of infused bFGF. There was no difference in bFGF mRNA expression between the control and the bFGF-treated groups. CONCLUSION: Exogenous bFGF infusion significantly augmented new blood vessel development at the flap-limb interface. Endogenous bFGF was up-regulated around the newly developed microvessels in control animals, and vessel growth correlated with the diffuse distribution of exogenous bFGF, implicating bFGF as an important factor in angiogenesis. Exogenous bFGF did not affect bFGF mRNA expression, suggesting that the regulation of bFGF is not under autocrine control.     

一种新的薄壁铜管切割方法

介绍了一种新的直型刀具切割薄壁铜管的方法，提供了其主要参数的计算．     

Emission cross section and fluorescence efficiency of Nd-pentaphosphate

The room-temperature cross sections for the Nd³⁺⁴F_{3/2}levels to the⁴I_{11/2}and⁴I_{9/2}manifolds (lower laser state and ground state, respectively) in NdP5O14are measured by two spectroscopic methods. A value for the largest cross section ofsigma(R_{1} - Y_{2}) = 1.7 times 10^{-19}cm²is found. The highest effective cross section, resulting from superposition of two lines at 1.051 μm, gives a laser gain per Nd ion which is about 2/3 of the maximum gain in YAG:Nd. The relative branching ratio into the⁴I_{11/2}and⁴I_{9/2}manifolds is 0.65:0.35. Comparison of the integrated cross sections with the measured lifetime for 1-percent Nd in LaP5O14indicates a combined efficiency <0.1 for the remaining transitions, namely radiative decay into the⁴I_{13/2}and⁴I_{15/2}manifolds and multiphonon quenching. A measurement of temperature dependence of fluorescence lifetime supports this last result.     

解非串并联系统可靠性最优化问题的一个简捷算法

本文分析了非串并联的桥式网络和混联网络在最佳冗余分配方面的特点,提出了以桥式 和混联网络作为典型环节的复杂系统可靠性最优化问题的简化原则,并推广应用文献[1]的简 捷算法来解复杂系统可靠性最优化问题.     

Application of the theory of optimal experiments to adaptive electromagnetic-induction sensing of buried targets

A mobile electromagnetic-induction (EM I) sensor is considered for detection and characterization of buried conducting and/or ferrous targets. The sensor maybe placed on a robot and, here, we consider design of an optimal adaptive-search strategy. A frequency-dependent magnetic-dipole model is used to characterize the target at EMI frequencies. The goal of the search is accurate characterization of the dipole-model parameters, denoted by the vector /spl Theta/; the target position and orientation are a subset of /spl Theta/. The sensor position and operating frequency are denoted by the parameter vector p and a measurement is represented by the pair (p, O), where O denotes the observed data. The parameters p are fixed for a given measurement, but, in the context of a sequence of measurements p may be changed adaptively. In a locally optimal sequence of measurements, we desire the optimal sensor parameters, p/sub N+1/ for estimation of /spl Theta/, based on the previous measurements (p/sub n/, O/sub n/)/sub n=1,N/. The search strategy is based on the theory of optimal experiments, as discussed in detail and demonstrated via several numerical examples.     

颌骨重建中的图像分割和轮廓对应及分支问题

根据人体颌骨的形状特征,提出一系列有针对性的方法,在CT断层数据的基础上重建三维表面模型．研究的内容包括医学图像的分割和从轮廓线重建表面两个方面．首先,采用一种称为“非种子区域分割”方法提取物体的轮廓线;然后,建立一条反应颌骨走向的弓形“参照基准线”,充分利用轮廓线相对于它的“归一化位置”信息解决表面重建中的对应和分支问题;同时考虑相邻层的影响,使生成的表面更加光滑、自然．最后,提出“多阶凸包点对应匹配”的思想,用分层分段迭代的方法拼接三角面片．     

Synthesis and biocompatibility of porous nano-hydroxyapatite/collagen/alginate composite

Porous nano-hydroxyapatite/collagen/alginate (nHAC/Alginate) composite containing nHAC and Ca-crosslinked alginate is synthesized biomimetically. This composite shows a significant improvement in mechanical properties over nHAC material. Mechanical test results show that the compressive modulus and yield strength of this composite are in direct proportion to the percentage of Ca-crosslinked alginate in the composite. Primary biocompatibility experiments in vitro including fibroblasts and osteoblasts co-culture with nHAC/alginate composite indicated the high biocompatibility of this composite. Therefore the composite can be a promising candidate of scaffold material for bone tissue engineering.     

数字区调新技术新方法—RS_OrthoMapper系统研制开发

为了适应当今数字区调工作的需要,开发一套3S技术有机结合简单实用的数字区调野外工作平台或软件系统,已成为燃眉之急。论文介绍了数字区调新技术新方法--RS_OrthoMapper系统研制与开发的基本需求、系统的总体结构与设计、系统实现等,并给出了系统中一些重要的逻辑视图。该系统在西藏昌务场和青海阿拉克湖等地区数字区调填图中示范应用,获得良好效果。     

Determination of alkylbenzyldimethylammonium chlorides in river water and sewage effluent by solid-phase extraction and gas chromatography/mass spectrometry

This study presents a modified method to analyze alkylbenzyldimethylammonium chlorides (ABDACs) in river water and sewage effluent. The method involves mixed samples with linear alkylbenzenesulfonates (LAS) as a counterion to enhance the extraction of ABDAC residues from an RP-18 solid-phase cartridge by formation of hydrophobic ion-pair complexes. The ABDACs were then eluted with methanol-ethyl acetate (1:1, v/v) and formed to their corresponding alkyldimethylamines by the Hofmann degradation with potassium tert-butoxide. The alkyldimethylamines were then identified and quantitated by gas chromatograph/mass spectrometry (GC/MS). The results indicate that, in the presence of LAS, debenzylation of ABDACs occurs selectively at a temperature higher than 90 degrees C to produce the corresponding nonionic alkyldimethylamines. The method proposed herein provides a high precision and sensitivity for ABDACs, to quantitation at < or =0.1 microg/L in 500 mL of the water samples. The average recovery of ABDAC spiked water samples was 95% with relative standard deviations (RSD, n = 7) of 9%. The RSDs of three replicate environmental sample analyses ranged from 5 to 11%. Direct HPLC method was applied to evaluate the GC/MS method, and compatible results were observed.