Plant mineral nutrition,gas exchange and photosynthesis in space: A review

Successful growth and development of higher plants in space rely on adequate availability and uptake of water and nutrients, and efficient energy distribution through photosynthesis and gas exchange. In the present review, literature has been reviewed to assemble the relevant knowledge within space plant research for future planetary missions. Focus has been on fractional gravity, space radiation, magnetic fields and ultimately a combined effect of these factors on gas exchange, photosynthesis and transport of water and solutes.     

Protein expression profile changes in human fibroblasts induced by low dose energetic protons

Extrapolation of known radiation risks to the risks from low dose and low dose-rate exposures of human population, especially prolonged exposures of astronauts in the space radiation environment, relies in part on the mechanistic understanding of radiation induced biological consequences at the molecular level. While some genomic data at the mRNA level are available for cells or animals exposed to radiation, the data at the protein level are still lacking. Here, we studied protein expression profile changes using Panorama antibody microarray chips that contain antibodies to 224 proteins (or their phosphorylated forms) involved in cell signaling that included mostly apoptosis, cytoskeleton, cell cycle and signal transduction. Normal human fibroblasts were cultured until fully confluent and then exposed to 2 cGy of 150 MeV protons at high-dose rate. The proteins were isolated at 2 or 6 h after exposure and labeled with Cy3 for the irradiated cells and with Cy5 for the control samples before loading onto the protein microarray chips. The intensities of the protein spots were analyzed using ScanAlyze software and normalized by the summed fluorescence intensities and the housekeeping proteins. The results showed that low dose protons altered the expression of more than 10% of the proteins listed in the microarray analysis in various protein functional groups. Cell cycle (24%) related proteins were induced by protons and most of them were regulators of G1/S-transition phase. Comparison of the overall protein expression profiles, cell cycle related proteins, cytoskeleton and signal transduction protein groups showed significantly more changes induced by protons compared with other protein functional groups.     

论我国人大立法过程中的利益表达

社会分层与社会利益多元化,必然导致社会各阶层谋求自己利益的立法认可。人民代表大会作为调控利益冲突、进行立法选择的主要场所,在组织结构、代表的组成与职责、立法程序．等方面,滞后于市场经济中社会利益多元化这一现实,有必要从强化代表的职责、优化代表大会的结构,规范立法程序,完善立法权的划分等方面加强我国的人大代表制度,以实现利益的有效表达,应对利益分化这一社会现实。     

最小支撑树算法在基因表达数据聚类分析中的应用

聚类分析已成为对基因表达数据进行挖掘以提取生物医学信息的主要方法.本文提出了基于图论的最小支撑树(Minimum spanning tree,MST)聚类算法,用MST表示多维基因表达数据,可将数据的聚类转换为对最小支撑树的分割,相对于传统聚类方法,最小支撑树算法具有形象直观、对一些准则函数能产生全局最优解等优点;将MST算法分别与Memetic algorithm及人工免疫算法(Artificial immune network,aiNet)相结合,则产生更优化的聚类结果.对酵母基因表达数据的实验结果表明,最小支撑树聚类算法是一种有效的基因表达数据的聚类方法.     

碰撞概率对轨道误差和接近几何条件的灵敏度分析

基于显式表达式对碰撞概率的灵敏度进行解析分析,给出其对接近距离的RSW分量、轨道误差、接近角度和目标大小的两类灵敏度（绝对灵敏度和相对灵敏度）。以美俄卫星碰撞事件为例进行计算和分析,得到灵敏度的变化曲线和数值。该解析方法可以克服数值分析方法中普遍存在的使用不便、计算量大、精度不高等问题。     

BHU人脸表情数据库的设计与实现

提供了一个较为全面的人脸表情数据库,它包含3类人脸表情:单一表情、混合表情和复杂 表情.本数据库具有在其它人脸数据库中未曾出现的情感表情,对世界人脸表情数据库进行 了有益的补充.对数据库单一表情的部分样本进行了问卷调查,给出了对每个样本的评价, 并通过统计分析给出了对数据库中单一表情可识别性的评价.通过对9 种单一表情的识别实验,说明了多类表情识别的可行性.本表情数据库对人脸表情识别和人 机交互领域的研究具有积极的促进作用.      

战术无人机总体与性能参数相关性分析

按照飞行器设计的基本原理并结合无人机特点,对侦察、监视类战术无人机总体参数与性能参数进行了相关性分析,找出了两者可能存在的数学关系,得到10个经验公式和一些重要参数的取值范围,可为战术无人机的概念设计提供有用的数据和参考。     

面向机务维护模拟机知识表达方法的研究

通过分析模拟机知识的特点和训练等级要求,根据模拟机系统功能原理操作和排故过程,提出面向对象的框架规则知识表达法。介绍该表达法的设计思路,建立框架结构、规则树和堆栈转换模式。最后进行实例分析,结果表明该方法具有可行性,为模拟机开发人员提供有效的仿真依据。     

Effects of space flight exposure on cell growth,tumorigenicity and gene expression in cancer cells

It is well recognized that harsh outer space environment, consisting of microgravity and radiation, poses significant health risks for human cells. To investigate potential effects of the space environment exposure on cancer cells we examined the biological changes in Caski cells carried by the “Shen Zhou IV” spaceship. After exposure for 7 days in spaceflight, 1440 survival subclonal cell lines were established and 4 cell lines were screened. 44F10 and 17E3 were selected because of their increased cell proliferation and tumorigenesis, while 48A9 and 31F2 had slower cytological events. Experiments with cell proliferation assay, flow cytometry, soft agar assay, tumorigenesis assay and DNA microarray analysis have shown that selected cell lines presented multiple biological changes in cell morphology, cell growth, tumorigenicity and gene expression. These results suggest that space environment exposure can make significant biological impact on cancer cells and provide an entry point to find the immunological target of tumorigenesis.