环境介质中有机污染物非靶向筛查技术研究进展

随着质谱质量精度的不断提高和物质数据库的扩大,高通量非靶向筛查技术快速发展,为组成复杂的环境介质中污染物的识别分析提供了有效手段。综述了环境分析中非靶向筛查技术［气相色谱-高分辩率质谱法（GC-HRMS）和液相色谱-高分辨率质谱法（LC-HRMS）］的研究进展,包括样品的前处理方法、非靶向分析平台、数据分析及存在的问题。简述了非靶向筛查技术在分析环境水样、沉积物样品及土壤样品中的应用,并提出该技术存在的问题和应用前景。     

电子产品环境应力筛选的技术及实施办法

环境应力筛选作为装备研制、生产中的一个非常重要的环节,结合有关标准,对环境应力筛选的作用、方法、裁减、实施办法等方面进行了阐述和论述。通过本文,使企业能够了解环境应力筛选的重要性,将此项工作落实到产品的研制/生产过程中,提高产品的可靠性,从而达到提升企业效益。     

金鱼藻中抑藻化感物质的研究

通过静态模拟实验,比较了单独培养和共生培养下,不同初始藻密度时金鱼藻生物量和铜绿微囊藻密度的变化.采用固相萃取的方法对金鱼藻种植水中的化感物质进行富集,经甲醇洗脱、高效液相色谱分析,发现在铜绿微囊藻生长的胁迫下,金鱼藻释放的化学物质组成和含量发生变化,强极性物质含量下降,弱极性物质含量增加.二氯甲烷洗脱物经色谱质谱分析后,检测出15种不同于铜绿微囊藻释放的化合物,其中N-苯基-2-萘胺、脱氢枞酸甲酯和脱氢枞酸乙酯已有文献报道对藻类具有化感作用.     

红壤溶磷菌的筛选及溶磷能力的比较

对不同利用方式下红壤的溶磷菌进行筛选,得到7株优势菌株,观察并测定了各初选菌株的菌落特征、生长速度及溶磷能力。结果表明,7株溶磷菌株的HD/CD值(溶磷圈直径HD与菌落直径CD的比值)范围在1.47~3.45之间,有效溶磷量在11.27~136.27 mg.L-1之间,均具有较强溶磷作用。其中,CY06菌株在固体培养条件下的HD/CD值和液体培养条件下的有效溶磷量均显著高于其他菌株,且该菌株对磷酸铝的有效溶磷量显著高于其他难溶磷酸盐,有望成为开发红壤高效微生物磷肥的优良微生物资源。     

Fetal blood sampling demonstrating chimerism in monozygotic twins discordant for sex and tissue karyotype (46,XY and 45,X)

Fetal blood sampling has been used in the genetic work-up of twin gestations for rapid karotyping. We present a case of twins which on ultrasound evaluation revealed hydrops fetalis in one twin and a normal second twin. Fetal blood sampling revealed the presence of mosaicism for 46,XY/45,X in both twins. HLA antigen testing showed the twins to be identical. The patient elected pregnancy termination. Blood chromosomal analysis after delivery revealed both twins to have 46,XY/45,X mosaicism, but the twin with signs of hydrops fetalis had tissue chromosomes of 45,X and the normal twin had tissue chromosomes of 46,XY. Amniotic fluid chromosomal analysis revealed 46,XY in twin A and 45,X in twin B. This represents a case of identical (monozygotic) twins with sex discordance. In this case, there was the probable occurrence of post-zygotic chromosomal non-disjunction leading to the discordancy of the sex in this set of twins. With the presence of vascular communication in monozygotic twins, there is the possibility of exchange of blood in monozygotic twins and the result of blood chimerism in twins.     

Maternal smoking habits and Down's syndrome

Two series of pregnancies were studied to investigate the relationship between maternal smoking and the risk of fetal Down' s syndrome. In the first series, ascertained in the 1960s, in which smoking habits were determined after the outcome of pregnancy was known, the proportion of smokers (47 per cent) among the 461 women whose pregnancies ended in the birth of an infant with Down' s syndrome was similar to that in the 461 controls (46 per cent) who had pregnancies affected by other congenital disorders. In the second series, ascertained between 1973 and 1984, smoking habits were determined by measurement of cotinine in antenatal serum samples that were routinely collected and stored or, if a serum sample was not available, from information in the antenatal notes. In this series, the proportion of smokers (14 per cent) among the 91 women who had pregnancies associated with Down' s syndrome was lower than that among 413 controls (19 per cent), though this was not statistically significant. Collectively, our results provide no evidence for an association between fetal Down' s syndrome and smoking. Other published studies found a deficit of smokers among women who had pregnancies associated with Down' s syndrome. This may be partly due to some studies not taking adequate account of maternal age (older women are more likely to have had a Down' s syndrome pregnancy but are less likely to be smokers) and partly due to the greater tendency for positive findings to be published than negative ones.