首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6篇
  免费   0篇
综合类   3篇
基础理论   2篇
污染及防治   1篇
  2016年   2篇
  2013年   1篇
  2006年   1篇
  1990年   1篇
  1986年   1篇
排序方式: 共有6条查询结果,搜索用时 138 毫秒
1
1.
2.
The determination of Ce, Co, Cr, Cs, Eu, Fe, Gd, Hf, Mn, Rb, Sb, Sc, Ta, Tb, Th, Zn, Zr and Yb by instrumental neutron activation analysis in sediment samples collected from the Gulf of Gaeta (Central Tyrrhenian Sea) is described. The granulometric fractions of the sediments were grouped by cluster analysis into three granulometric facies (sand, clayey silt, and silty clay) which were then assumed to be the main factors controlling the distribution patterns of the elements. This assumption was confirmed by a discriminant analysis carried out on the trace element data.  相似文献   
3.
The notorious difficulties encountered in species identification of bivalve larvae through morphological characters have given rise to several alternative molecular approaches. In the present work, we propose a method based on PCR-SSCP combined with sequencing of partial 18S rDNA region, in which a large number of larvae can be scored and species identified with minimum sequencing effort. A primer set was developed to amplify a taxonomically informative 18S region of fragment size suitable for high resolution PCR-SSCP. The method developed is fast processing and has the potential of identifying most species present in a plankton sample with low economic efforts. Those species for which partial 18S sequences are not yet available from GenBank, can be identified in families or at higher categories. The method was also tested on nine species and two subspecies of commercial importance in Italy to be carried out by the use of PCR-SSCP alone without sequencing.  相似文献   
4.
5.
Abstract

Mikania glomerata Sprengel, popularly known as “guaco,” is used in Brazilian folk medicine for several inflammatory and allergic conditions. Besides, the popular use “guaco” is indicated by the Brazilian Ministry of Health as a safe and effective herbal medicine. The biological activity of M. glomerata extracts is due to the presence of the coumarins, a large family of phenolic substances found in plants and is made of fused benzene and α-pyrone rings. Considering that there are few data on the biological effects of the extracts of M. glomerata, mainly in genetic level, this work aims to evaluate, in vitro, the genotoxicity and coumarin production in M. glomerata in conventional and organic growing. The data showed that the organic culture system showed double the concentration of coumarin being significantly more productive than the conventional system. Besides, the results of comet assay suggest that extracts of M. glomerata cultivated in a conventional system was genotoxic, increased DNA damage levels while the organic extracts seem to have antigenotoxic effect possibly due to the concentration of coumarins. Additional biochemical investigations are necessary to elucidate the mechanisms of action of M. glomerata extracts, which were found to have a role in protection against DNA damage.  相似文献   
6.
Five hundred cordocenteses were performed between 12 and 21 weeks. The indications were thalassaemia (386), rapid karyotyping (97), feto-maternal allo-immunization (10), rubella (6), and toxoplasmosis (1). One hundred and ten pregnancies underwent termination on the basis of the result, while 20 of the 370 pregnancies intended to continue were lost to follow-up. Amongst these were 16 fetal losses (4·3 per cent) and 22 premature deliveries (5·9 per cent); no other complications were reported. Four adverse prognostic factors were identified: (a) cord bleeding; (b) fetal bradycardia; (c) prolonged procedure time; and (d) anterior insertion of the placenta. There was no‘obvious’ difference in fetal loss rate with advancing gestation until 19–21 weeks, when the risk of fetal loss decreased to 2·5 per cent.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号