TOP QUARK MASS AND THE FOURTH GENERATION OF QUARK

To explain CP violation in Kaon system in the light of the recently measured b - lifetime within the framework of three generations of quarks, the top quark mass has to be greater than 50GeV if the current algebra value of the factor BK is adopted and | ε’/ε|< 0.01. In this letter a fourth generation of quark is considered which can fit the present experimental data on CP violation, and KL→ μ ^(+) μ^(- )decay rate for top quark mass is around 40GeV. The mass of the new charge 2/3 quark is predicted to be over 100Gev.

An Exact Numerical Approach to Calculate the First Passage Time for General Random Walks on a Network

We present an exact numerical method to calculate the mean first passage time for the random walk on the network between any source node and any target which contains an arbitrary number of nodes.For the network with the average degree<k>~O(1)and the effective diameter D~lnN or less,the efficiency of our numerical approach is found to exceed all other general numerical methods presented in the literature.Our method can also calculate the average of any function of the first passage time,provided it is finite.

应用多重荧光PCR快速筛查作物中转基因成分研究

通过对我国批准进口的和获得农业转基因生物安全证书的转基因玉米转化体的序列分析发现,除DAS40278-9和BLVA430101外,CaMV35s启动子、NOS终止子、Cry1Ab/Ac基因和pat基因覆盖了21种玉米转基因转化体。通过引物组合筛选、反应体系优化、灵敏度测试、适用性测试等实验,建立了基于4个通用筛选元件及zSSIIb内源基因的五重荧光PCR和基于转化体特异性序列的二重荧光PCR检测转基因成分方法体系。方法参数测定结果表明,此方法特异性强、稳定性好,检测灵敏度达到0.05%。同时,此方法体系不仅适用于转基因玉米成分筛查,对大豆、水稻等多种作物进行转基因成分筛选鉴定也有良好的适用性。

转基因耐除草剂玉米ZZM030对草铵膦、草甘膦及非靶标除草剂的耐受性评价

采用田间试验,鉴定小区随机区组排列,对转基因玉米ZZM030和对应的非转基因对照祥249进行不同用量的草甘膦、草铵膦及非靶标除草剂的喷施处理,分别在用药后7、14、28 d调查和记录成苗率、植株高度、药害症状,评价该转基因玉米品系的目标性状有效性和对非靶标除草剂耐受性。结果表明,转基因玉米ZZM030对草铵膦和草甘膦具有良好的耐受性,对玉米田其他常用除草剂阿特拉津和烟嘧磺隆也具有良好的耐受性,不耐受玉米敏感型除草剂精喹禾灵和稀禾啶。

脂蛋白在药物递送中的应用研究进展

脂蛋白是脂质-蛋白质类球形大分子复合物,在控制脂质代谢中起主要作用,可用于治疗剂的靶向输送。近年来,随着纳米药物的不断创新,脂蛋白被应用到不同的药物递送系统中,靶向递送脂溶性化疗药物是近年来兴起的一种极具发展潜力的药物递送载体。该文对脂蛋白的分类、特点和不同类型脂蛋白作为纳米药物递送载体的研究进展进行了综述。