Kinetic evaluation of the size-dependent decomposition performance of solvent-free microcellular polylactic acid foams

A thermal gravimetric method is described for evaluating the kinetics of cell size-dependent decomposition and lifetime estima- tion for microcellular tissue engineering scaffolds made of biodegradable polylactic acid(PLA)foams.PLA foam cell sizes from 550 to 20?m were fabricated experimentally using a solvent-free solid-state foaming technique under saturation pressures from 1 to 5 MPa.The thermal properties of the PLA foams with respect to the cell sizes were measured using thermal gravimetric analy- sis in a nitrogen atmosphere and the activation energy and pre-exponential factor were derived to evaluate the decomposition ki- netics and estimate lifetime.It was found that small cell sizes can be achieved under high saturation pressures and that the thermal stability of PLA decreases after the fabrication process.The cell size-dependent thermal stability and degradation rate indicate that a PLA foam of larger cell sizes has a shorter degradation time,a few tenths that of the PLA raw material,at a temperature of 37°C. The results suggest that it is feasible to optimize fabrication parameters to obtain appropriate cell sizes and lifetimes that satisfy the application requirements for various organs.This study provides the basis for precise scaffold design and quantitative analysis of PLA foams in tissue engineering applications.     

自体造血干细胞移植后的胸腺近期输出功能

目的:了解血液病患者接受自体造血干细胞移植(auto-HSCT)后外周血中的T细胞受体重排删除环(TRECs)水平,从而了解其胸腺近期输出功能和T细胞免疫重建情况。方法:采用实时定量PCR法检测9例血液病患者经auto-HSCT治疗后外周血单个核细胞(PBMNCs)中的TRECs水平;22例正常人外周血样本作为对照。结果:PBMNCs中的TRECs水平有着较大的个体差异,年龄与PBMNCs中的TRECs水平呈负相关;auto-HSCT组的每1 000个PBMNCs中的TRECs平均拷贝数(2.533±4.194)明显低于正常组(4.367±3.626)(P<0.05),但部分病例的TRECs水平已基本达到正常水平。结论:在一定时间内,auto-HSCT后的胸腺近期输出功能仍较低,不同个体T细胞免疫重建时间存在差异。     

多尺度自适应加权形态边缘检测方法

针对常用的多尺度边缘检测方法因卷积运算造成模糊图像边缘，提出一种多尺度自适应加权形态边缘检测方法，利用大小不同的结构元素提取图像边缘特征，在大尺度下抑制噪声，可靠地识别边缘，在小尺度下定位，再由粗到细跟踪边缘，得到边缘的位置，再由各尺度结构元的抗噪性确定加权值的大小，然后加权处理得到最后的边缘结果，实验表明，用多尺度自适应加权形态边缘检测算法可得到较理想的图像边缘。     

肾癌淋巴结切除术的进展

本文对肾癌治疗中淋巴结切除的问题作了回顾性总结，当前，在肾癌术中作出行淋巴结切除术的决定仍是复杂的。尽管如此，对那些有淋巴结转移高风险或者已有明确淋巴结转移，但没有远处转移的患者来说，淋巴结切除术仍有可能起到根治的作用。我们也探讨了腹腔镜肾癌根治术和保留肾单位肾癌切除术中淋巴结切除术的原则，一般情况下，不采用典型区域淋巴结切除术。     

靶向survivin基因的shRNA慢病毒载体的构建及其对膀胱癌EJ细胞凋亡的影响

目的:构建survivin基因特异性shRNA慢病毒干扰载体,转染膀胱癌EJ细胞,研究survivin基因在膀胱癌细胞株中的表达抑制情况,观察survivin shRNA慢病毒载体对EJ细胞凋亡的影响.方法:以survivin基因为靶标设计shRNA干扰序列,克隆至p SIH1-H1-cop GFP慢病毒载体.干扰载体鉴定正确后转染膀胱癌细胞株EJ细胞,荧光显微镜下观察GFP表达情况,实时荧光定量PCR检测survivin基因mRNA含量变化,Western blotting法检测survivin蛋白表达,Annexin V-FITC/PI双染法检测EJ细胞凋亡情况.结果:PCR扩增鉴定、DNA测序证实survivin慢病毒干扰载体构建成功;EJ细胞经干扰载体处理后,EJ细胞survivin基因mRNA水平下调了73.33%,蛋白表达受到显著抑制,EJ细胞凋亡率达到24.39%.结论:成功构建了靶向survivin基因的shRNA重组慢病毒干扰载体,可以显著降低转染细胞survivin基因的表达水平,并有效提高膀胱癌细胞凋亡率.     

Control system design of hybrid fuel cell city bus

This paper introduced the design of the hybrid powertrain of the Fuel Cell City Bus demonstrated in 2008 Beijing Olympic Games. The configuration of the hybrid fuel cell powertrain was introduced. The safety of hydrogen storage and delivery system, the hydrogen leakage alarm system were developed. The real-time distributed control and diagnosis system based on the Time Trigger Controller Area Network (TTCAN) with 10 ms basic control period was developed. The concept and implementation of processor (or controller) monitor and process (or task) monitor technique based on the TTCAN were applied in this paper. The fault tolerant control algorithm of the fuel cell engine and the battery management system were considered. The demonstration experience verified that the fault tolerant control was very important for the fuel cell city bus.     

TiO2薄膜结构特征初探

主要研究了半导体材料TiO2的部分特征,光谱吸收率与TiO2膜厚度成正比,TiO2膜在烧结前呈水合物团块状结构,表面粗糙度大, 空气中烧结后呈等粒或椭圆粒状镶嵌结构, 表面粗糙度比未烧的小,在抽真空加氮气烧结后成等粒状结构,表面较光滑,在空气中烧结的TiO2膜放至光敏染料中泡1 h后呈等粒状结构,表面较光滑.从TiO2光电池器件输出电功率来看,TiO2膜在空气中烧至450 ℃时的电输出的功率比在氮气中烧至530 ℃的高,印刷TiO2膜的丝网目数为500目时,电输出功率较佳.     

Multifunctions of histone H1 proteins

Among various histones, histone H1 proteins have been appreciated for their multiple functions in diverse biological processes. In addition to being a structural protein in chromatin, H1 proteins also play critical roles in cell cycle, gene expression, and development. Recent studies reveal the possible effects of H1 in some diseases, such as cancer and neurodegenerative diseases. Here, we review different variants of HI, the functions, and post translational modifications of ill variants are also discussed.     

碳纳米管光伏器件的研究进展

碳纳米管（CNT）具有优异的电学特性和独特的一维纳米结构,是制作光伏器件的良好材料.文中介绍了单根/多根CNT光伏器件、CNT薄膜光伏器件、CNT 有机光伏器件、杯状叠层CNT光伏器件等典型CNT光伏器件,并阐述了这些CNT光伏器件的结构及特性,分析了CNT在器件中的作用.     

灵菌红素及其应用前景

灵菌红素是一类含甲氧基吡咯骨架结构的天然色素,是一些放线菌、沙雷菌及其他细菌的次级代谢产物,具有免疫抑制、抗细菌、抗真菌和抗疟疾等多种生物活性。最近研究表明灵菌红素有很强的抗肿瘤及免疫抑制活性,因而成为研究热点。本文结合本实验室所开展的相关研究工作对灵菌红素的种类、理化性质、生物活性及应用前景作一综述。