氢化物发生—原子荧光光谱法测定桉树叶、皮、躯干、根中硒含量

以铁氰化钾为掩蔽剂,1.5% KBH4为还原剂,10%的盐酸为载流液,微波消解处理样品,氢化物发生-原子荧光法(HG-AFS)分别测定桉树叶、皮、躯干和根中硒元素含量。加标回收验证了结果的准确性。考察了仪器测定硒的检出限。并对铁氰化钾,聚环氧琥珀酸(PESA),酒石酸,柠檬酸,乙二胺五种掩蔽剂对11种常见干扰元素的掩蔽效果进行了探究,为优良掩蔽剂的选择提供了参考性资料。     

一类具有阶段结构的传染病模型的全局分析

通过建立一类具有阶段结构的传染病模型,得到了系统解的永久持续性,并通过构造Liapunov函数和定性分析得到了各类平衡点的全局稳定性的充分条件.     

Autophagy regulates spermatid differentiation via degradation of PDLIM1

Spermiogenesis is a complex and highly ordered spermatid differentiation process that requires reorganization of cellular structures. We have previously found that Atg7 is required for acrosome biogenesis. Here, we show that autophagy regulates the round and elongating spermatids. Specifically, we found that Atg7 is required for spermatozoa flagella biogenesis and cytoplasm removal during spermiogenesis. Spermatozoa motility of atg7-null mice dropped significantly with some extra-cytoplasm retained on the mature sperm head. These defects are associated with an impairment of the cytoskeleton organization. Functional screening revealed that the negative cytoskeleton organization regulator, PDLIM1 (PDZ and LIM domain 1 [elfin]), needs to be degraded by the autophagy-lysosome-dependent pathway to facilitate the proper organization of the cytoskeleton. Our results thus provide a novel mechanism showing that autophagy regulates cytoskeleton organization mainly via degradation of PDLIM1 to facilitate the differentiation of spermatids.     

Eremophilane Sesquiterpenes from the Genus Ligularia

Ligularia speices are widely used in Asian folk medicines for the treatment of various human diseases. Eremophilane‐type sesquiterpenes are abundant and typical secondary metabolites found in this genus. Over 500 eremophilanes reported from members of Ligularia are reviewed in this article together with bioactivity data in an effort to highlight the development in this field.     

Hygiene Behaviors Associated with Influenza-Like Illness among Adults in Beijing,China: A Large,Population-Based Survey

The objective of this study was to identify possible hygiene behaviors associated with the incidence of ILI among adults in Beijing. In January 2011, we conducted a multi-stage sampling, cross-sectional survey of adults living in Beijing using self-administered anonymous questionnaires. The main outcome variable was self-reported ILI within the past year. Multivariate logistic regression was used to identify factors associated with self-reported ILI. A total of 13003 participants completed the questionnaires. 6068 (46.7%) of all participants reported ILI during the past year. After adjusting for demographic characteristics, the variables significantly associated with a lower likelihood of reporting ILI were regular physical exercise (OR 0.80; 95% CI 0.74–0.87), optimal hand hygiene (OR 0.87; 95% CI 0.80–0.94), face mask use when going to hospitals (OR 0.87; 95% CI 0.80–0.95), and not sharing of towels and handkerchiefs (OR 0.68; 95% CI 0.63–0.73). These results highlight that personal hygiene behaviors were potential preventive factors against the incidence of ILI among adults in Beijing, and future interventions to improve personal hygiene behaviors are needed in Beijing.