城市老工业搬迁区河道PAHs分布特征及其生态风险——以沈阳市卫工河为例

为查明城市老工业搬迁区景观河道中多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的分布特征并评估其生态风险,于2011年10月至2012年9月期间,以沈阳市卫工河为研究对象,调查了河水和底泥中16种国家环保部优先控制的PAHs环境滞留情况.通过季节性采样和沿河采样,初步查明了PAHs的时空分布特征,用熵值法初步评价了PAHs滞留的生态风险.结果表明:卫工河水中PAHs的平均质量浓度为0.721μg·L-1,底泥中PAHs平均质量分数为3 777.8 ng·g-1.河水与底泥中PAHs含量与溶解态有机碳含量均呈正相关关系.熵值法分析结果表明,卫工河PAHs滞留存在中度偏低水平的生态风险,但在某些样点区,底泥中萘和蒽的生态风险值较高.     

FM-IM光纤模拟接收机设计

ＦＭ－ＩＭ 模拟信号传输方式的光纤通信系统与直接强度调制、基带模拟传输方式 相比，有明显的优点，其信噪比可提高１．７＋２０１ｏｇβＦＭ（ｄＢ）．本文试图寻求一种适 用于 ＦＭ－ＩＭ光接收机前端的工程设计方法，以便较好地确定光检测器、前置低噪声 放大器的类型及其主要参数．     

Shape change of human blood platelets: Reliable and fast detection by quasi-elastic light scattering

Quasi-elastic light scattering has been used for the first time to obtain reliable information about the morphology of platelets under physiological conditions within a short time. By measuring two independent parameters (electrophoretic mobility and diffusion coefficient) it is possible to distinguish between different stages of shape change on the one hand, and between shape change and binding of particles to the platelet surface without shape change on the other hand.     

Biodegradation of bitumen used for nuclear waste disposal

Summary Studies have been carried out to test microbial degradation of bitumen used for encapsulating radioactive waste in Sweden. Microorganisms have been isolated that degrade bitumen. In ong-term tests under conditions simulating those in the silo part of the final repository for low-and intermediate-level radioactive waste, both aerobic and anaerobic degradation of bitumen has been found, equivalent to 0.6–1.5 moles CO₂/month·mg bitumen and 1.1–1.5 moles CO₂/month·mg bitumen, respectively.     

植物对PAHs胁迫响应及植物修复研究进展

探讨国内外关于植物吸收多环芳烃(PAHs)的途径、PAHs胁迫对植物生长的影响、植物对PAHs胁迫的生理响应,以及PAHs污染的植物修复等方面的研究进展.分析认为,目前的研究缺乏植物对PAHs胁迫响应的生物化学、分子机制的新途径,且现有的植物修复方法存在生物量较低、针对性不强、效率不高等缺点.最后,进一步展望值得探究的相关技术和问题.     

The role of sediment resuspension duration in release of PAHs

Polycyclic aromatic hydrocarbons （PAHs） are ubiquitous environmental pollutants. Due to their low water solubility and high hydrophobicity, PAHs are rapidly sorbed onto particles and subsequently deposit in sediments once introduced into aquatic environment. In such a way, sediments become a huge sink for PAHs. During sediment resuspension, the potential exists for PAHs to be released from sediments into water. Sediment resuspension plays an important role in the transportation and fate of PAHs in the aquatic environment. In this study, release behavior of PAHs on Yangtze River sediment during resuspension was investigated using a particle entrainment simulator （PES）. The role of resuspension duration on release of 16 PAHs was measured by resuspending sediment for 12 h at 0.2 and 0.5N/m^2, respectively. Results indicated that PAH concentrations in TSS increase over time with more increase of phenanthrene and 4-ring PAHs. Comparing with 0.2 N/m2 （30%）, TPAHs concentrations in TSS demonstrated remarkable increase during 0.5 N/m2 resuspension （37%）. Dissolved PAH concentrations increased throughout the duration with more increase of 2-3 ring PAHs （50%-88%）. Dissolved PAH concentrations showed remarkable increase during 0.5 N/m^2 resuspension （50%）. Moreover, PAH concentrations in overlying water throughout the duration of resuspension were higher than toxic effects threshold values in drinking water developed by WHO, which may cause toxic effect on ecosystem.     

不同贮藏方法及光照对马尾松花粉活力的影响

对马尾松花粉在不同贮藏方法及光照下花粉发芽率和花粉和长度变化的分析。结果表明：１．在干燥的状态下,贮藏的温度越低、保存花粉生活力的效果越好;２;在黑光条件下,马尾松花粉发芽率较其它光照条件下高,但它们的差异未达到显著水平;３．在黑光条件下,马尾松花粉和长度较其它光照条件下长,它们之间差异在到极显著水平。最后,对马尾松花粉贮藏方法及光照对花粉萌发的影响进行了讨论。     

Property of alumina to adsorb long chain normal-paraffin hydrocarbons

That alumina can strongly absorb long chain normal-paraffin hydrocarbon was found when alumina was used in the preparative group-type separation of heavy petroleum fractions. The reason for the above property of alumina may be that the normal-paraffin hydrocarbons can extend closely on the alumina surface.One molecule of long chain normal-paraffin hydrocarbon can be adsorbed by many active sites of alumina surface. The longer chain normal-paraffin hydrocarbon can be adsorbed by more active sites of alumina surface; this results in the longer chain normal-paraffin hydrocarbon has a stronger adsorption on alumina.     

Effect of continuous illumination on secretion of pregnane compounds by the rat ovary

Summary Differences in the secretion of pregnance compounds from rats with follicular polycystic ovaries under constant light and with normal preovulatory ovaries under light-dark conditions were compared. The injection of LH greatly increased the secretion of progesterone. 5-pregnane-3,20-dione and 3-hydroxy-5-pregnan-20-one, in both types of ovaries, but the response of the two progesterone metabolites in the polycystic ovaries was low, suggesting low 5-reductase activity.Acknowledgments. The authors thank the Endocrinology Study Section, NIADDK, Bethesda, MD, USA. for their gift of LH. This study was supported by Research Grant No. 466 154 from the Ministry of Education, Science, and Culture, Japan.     

Bifunctional enzyme FBPase/SBPase is essential for photoautotrophic growth in cyanobacterium Synechocystis sp. PCC 6803

From a random insertion mutant library of Synechocystis sp. PCC 6803, a mutant defective in photoautotrophic growth was obtained. The interrupted gene was identified to be slr2094 （fbpl）, which encodes the fructose-1,6-biphosphatase （FBPase）/sedoheptulose-1,7-biphosphatase （SBPase） bifunctional enzyme （F-I）. Two other independently constructed slr2094 mutants showed an identical phenotype. The FBPase activity was found to be virtually lacking in an slr2094 mutant, which was sensitive to light under mixotrophic growth conditions. These results indicate that slr2094 is the only active FBPase-encoding gene in this cyanobacterium. Inactivation of photosystem II by interrupting psbB in slr2094 mutant alleviated the sensitiveness to light. This report provides the direct genetic evidence for the essential role of F-I in the photosynthesis of Synechocystis sp. PCC 6803.