Analysis of the Surface Ozone During Summer and Autumn at a Coastal Site in East China

The levels and temporal variations of surface ozone at a coastal site in East China during summer and autumn were analyzed and the influences of meteorological parameters on ozone were investigated. An inland city was chosen as a comparison site. The main results and conclusions of this study are: (1) ozone pollution, with a maximum 1 h concentration of 150.98 ppbv, was severe during summer and autumn at the coastal site; (2) the ozone level was obviously higher at the coastal site than that at the inland site in September; (3) besides temperature and solar radiation, sea-land breeze circulation is an important factor influencing the ozone level at the coastal site, and sea breeze often induce high ozone levels (the average ozone concentration for sea breeze was about 13 ppbv higher than that for land breeze).     

Working‐correlation‐structure identification in generalized estimating equations

Selecting an appropriate working correlation structure is pertinent to clustered data analysis using generalized estimating equations (GEE) because an inappropriate choice will lead to inefficient parameter estimation. We investigate the well‐known criterion of QIC for selecting a working correlation structure, and have found that performance of the QIC is deteriorated by a term that is theoretically independent of the correlation structures but has to be estimated with an error. This leads us to propose a correlation information criterion (CIC) that substantially improves the QIC performance. Extensive simulation studies indicate that the CIC has remarkable improvement in selecting the correct correlation structures. We also illustrate our findings using a data set from the Madras Longitudinal Schizophrenia Study. Copyright © 2008 John Wiley & Sons, Ltd.     

枯草杆菌Bacillus sp F26产过氧化氢酶的发酵条件

从内蒙古呼伦贝尔草原的盐碱湖中分离到的一株低度嗜盐嗜碱细菌Bacillus sp F26，能积累高水平过氧化氢酶（CAT）。对Bacillus sp F26发酵产过氧化氢酶的环境与营养条件的研究结果表明，其积累高水平过氧化氢酶的适宜环境条件为：温度37℃，种龄20-22h，接种量5％，装液量50mL／（250mL的摇瓶）。适宜发酵培养基组成（g／L）为：葡萄糖15，牛肉膏10，玉米浆10，酵母膏5，磷酸二氢钾1，氯化镁0．2，氯化钠50，碳酸钠10。采用上述条件进行摇瓶分批发酵实验，发酵20h，过氧化氢酶酶活达到16．32U／mL，细胞干重为4．12g／L。进一步研究发现，在对数生长后期（16h）添加2mmol／L的H2O2可以明显刺激产酶，在5L的发酵罐上进一步以指数速率方式流加H2O2，由于该流加方式可降低H2O2对细胞的毒害作用，过氧化氢酶酶活达到29．89U／mL，与分批发酵相比提高了92．8％。     

Biochemical analysis of human milk treated with sodium dodecyl sulfate, an alkyl sulfate microbicide that inactivates human immunodeficiency virus type 1.

Reduction of transmission of human immunodeficiency virus type 1 (HIV-1) through human milk is needed. Alkyl sulfates such as sodium dodecyl sulfate (SDS) are microbicidal against HIV-1 at low concentrations, have little to no toxicity, and are inexpensive. The authors have reported that treatment of HIV-1-infected human milk with < or = 1% (10 mg/mL) SDS for 10 minutes inactivates cell-free and cell-associated virus. The SDS can be removed with a commercially available resin after treatment without recovery of viral infectivity. In this article, the authors report results of selective biochemical analyses (ie, protein, immunoglobulins, lipids, cells, and electrolytes) of human milk subjected to SDS treatment and removal. The SDS treatment or removal had no significant effects on the milk components studied. Therefore, the use of alkyl sulfate microbicides to treat milk from HIV-1-positive women may be a simple, practical, and nutritionally sound way to prevent or reduce transmission of HIV-1 while still feeding with mother's own milk.