用电荷检测离子阱质谱技术测量聚苯乙烯球粒子的质量

采用高速电荷检测离子阱质谱技术(CDIT-MS)测量了聚苯乙烯球的质荷比和所带电荷数,得到了聚苯乙烯球粒子的质量;通过对数百次测量结果的统计,给出了粒子的质量分布图,并用Gaussian线型对质量分布图进行了拟合,得到聚苯乙烯球的平均质量为1.93×10-13kg,与理论质量(~2.03×10-13kg)接近.结果表明,电荷检测离子阱质谱技术能有效测量微米离子的质量,且测量时间短、准确性高.     

关于物质颜色起因的探讨

从分子内部结构的角度对物质颜色的起因进行了探讨     

大体积混凝土施工防裂技术探讨

;从混凝土原材料选择、拌和、运输、浇筑、养护等方面阐述了大体积混凝土施工的防裂技术。     

CD95's deadly mission in the immune system

Apoptosis in the immune system is a fundamental process regulating lymphocyte maturation, receptor repertoire selection and homeostasis. Thus, death by apoptosis is as essential for the function of lymphocytes as growth and differentiation. This article focuses on death receptor-associated apoptosis and the role of CD95 (Apo-1/Fas)-mediated signalling in T-cell and B-cell development and during the course of an immune response. Gaining an insight into these processes improves our understanding of the pathogenesis of diseases such as cancer, autoimmunity and AIDS, and opens new approaches to rational treatment strategies.     

温州市群众体育现状调查与分析

通过对温州市区群众体育活动情况的抽样调查并对温州市群众体育体育活动情况的现状进行分析,提出了发展温州市群众性体育活动的一些建议。     

探讨群众体育发展的现状与对策

采用文献资料，逻辑演绎，归纳等研究方法，对上饶市群众体育发展的现状作调查分析，并针对我市群众体育的落后现状，对照国内其它城市群众体育的先进经验，提出对我市群众体育的改革对策。     

对科学发展观下拓宽城镇群众体育道路的研究探讨

就国务院未来发展群众体育的政策,分析当前群众体育面临的机遇与挑战,如何就现有的条件拓宽群众体育的外部环境,对现有资源进行有效整合等问题展开研究探讨。虽然目前群众体育没有竞技体育那样辉煌和受人关注,但随着经济的发展和人民生活水平的提高,余暇时间的增多,会有越来越多的市民参与到群众体育中来。因此,根据城市现有经济条件和体育设施开展好群众体育显得尤为重要。     

摩托化行军模拟分析与设计

分析了摩托化行军的特性以及影响摩托化机动的各种因素,从保证行车安全和拒绝插车两方面考虑,确定了车头时距和车头间距,建立了摩托化行军车辆跟驰计算模型,并介绍了摩托化行军计算机模拟系统的组成.     

白蚁mtDNA提取方法改良及检测

利用mtDNA多态性进行种类鉴定是一种分子生物学常用方法,从DNA水平对白蚁进行物种鉴别并探讨物种的进化,其必要前提是提取到一定数量和质量的mtDNA．在分离得到线粒体后,分别采用CTAB、SDS2种方法提取mtDNA．紫外分光光度计检~I]DNA纯度及浓度,用mtDNA特异性引物进行PCR扩增检测．试验证明2种方法均能成功提取白蚁的mtDNA,SDS法提取效果较好．     

Biomechanics: deadly strike mechanism of a mantis shrimp

Stomatopods (mantis shrimp) are well known for the feeding appendages they use to smash shells and impale fish. Here we show that the peacock mantis shrimp (Odontodactylus scyllarus) generates an extremely fast strike that requires major energy storage and release, which we explain in terms of a saddle-shaped exoskeletal spring mechanism. High-speed images reveal the formation and collapse of vapour bubbles next to the prey due to swift movement of the appendage towards it, indicating that O. scyllarus may use destructive cavitation forces to damage its prey.     

承台大体积混凝土温度应力分析与裂缝控制探讨

从弹性地基上长条板受力计算模型出发,分析了其温度应力的变化规律,指出温度应力的变化规律可作为判断承台大体积混凝土是否开裂的依据,并给出了施工现场温度裂缝控制的一些建议。     

J^pc相同的共振态的质量、宽度公式

本文提出J~(pc)相同的介子共振态质量公式是等距的M=M_0 BI推广到重子共振态,对Λ和Σ取平均值则质量公式为M=M_0 AS。它们和实验很好符合。相应的共振态宽度也是等距的。     

Sub-poissonian loading of single atoms in a microscopic dipole trap.

The ability to manipulate individual atoms, ions or photons allows controlled engineering of the quantum state of small sets of trapped particles; this is necessary to encode and process information at the quantum level. Recent achievements in this direction have used either trapped ions or trapped photons in cavity quantum-electrodynamical systems. A third possibility that has been studied theoretically is to use trapped neutral atoms. Such schemes would benefit greatly from the ability to trap and address individual atoms with high spatial resolution. Here we demonstrate a method for loading and detecting individual atoms in an optical dipole trap of submicrometre size. Because of the extremely small trapping volume, only one atom can be loaded at a time, so that the statistics of the number of atoms in the trap, N, are strongly sub-poissonian (DeltaN2 approximately 0.5N). We present a simple model for describing the observed behaviour, and we discuss the possibilities for trapping and addressing several atoms in separate traps, for applications in quantum information processing.     

李普曼的"拟态环境"理论的传播学意义探微

美国新闻工作者李普曼在<舆论学>一书中提出了"拟态环境"理论.这一理论在新闻传播史上极具理论价值,揭示了大众传播媒介的隐性功能,又是议程设置理论的思想渊源,同时对于我国开展好舆论引导工作也颇有现实指导意义.     

白蚁消化系统解剖构造及共生物研究进展

对白蚁消化系统的解剖结构与功能、白蚁消化道内外共生生物区系及其消化机理等方面的研究进行了综述.大量研究表明,白蚁消化系统具有发达的唾腺和后肠,不同种类和品级个体间消化道各组成部分的发达程度和折叠方式存在明显差异,在结构上呈现由低等白蚁向高等白蚁渐变复杂的趋势.白蚁消化道内共生生物包括原生动物、螺旋体和细菌,蚁巢伞属真菌以菌圃的形式与高等培菌白蚁建立消化道外的共生关系.目前,消化营养已经成为白蚁取食引诱等防治技术开发的重要靶标.     

EphrinB2 is the entry receptor for Nipah virus, an emergent deadly paramyxovirus

Nipah virus (NiV) is an emergent paramyxovirus that causes fatal encephalitis in up to 70 percent of infected patients, and there is evidence of human-to-human transmission. Endothelial syncytia, comprised of multinucleated giant-endothelial cells, are frequently found in NiV infections, and are mediated by the fusion (F) and attachment (G) envelope glycoproteins. Identification of the receptor for this virus will shed light on the pathobiology of NiV infection, and spur the rational development of effective therapeutics. Here we report that ephrinB2, the membrane-bound ligand for the EphB class of receptor tyrosine kinases (RTKs), specifically binds to the attachment (G) glycoprotein of NiV. Soluble Fc-fusion proteins of ephrinB2, but not ephrinB1, effectively block NiV fusion and entry into permissive cell types. Moreover, transfection of ephrinB2 into non-permissive cells renders them permissive for NiV fusion and entry. EphrinB2 is expressed on endothelial cells and neurons, which is consistent with the known cellular tropism for NiV. Significantly, we find that NiV-envelope-mediated infection of microvascular endothelial cells and primary cortical rat neurons is inhibited by soluble ephrinB2, but not by the related ephrinB1 protein. Cumulatively, our data show that ephrinB2 is a functional receptor for NiV.     

Characterization of enhancer trap and gene trap harboring Ac／Ds transposon in transgenic rice

Insertion mutagenesis has become one of the most popular methods for gene functions analysis.Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice.The excision of Ds element was examined by PCR amplification.The excision frequency of Ds element varied from 0% to 40% among 20 F2 populations derived from 11 different Ds parents.Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice.The result of histochemical GUS analysis indicated that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots,flowers or seeds.The GUS positive lines will be useful for identifying gene function in rice.