摘要:

Molecular Quantum Similarity is discussed to be a satisfactory chemical tool to develop QSARs for the toxicity of aromatic narcotic pollutants to fishPoecilia reticulata.The method is presented as a possible alternative to the use of classical 2D QSAR descriptors, such as logP, Hammett's sigma, or HOMO and LUMO energies, and it is based upon the information extracted from the quantitative similarity measures between the overall molecular pairs of the studied set. A systematic study of medium size homogeneous sets is performed, and finally an analysis of the full set is carried out. In all cases, satisfactory prediction models are achieved using few parameters. The stability and reliability of QSARs are tested by cross-validation, randomisation and real prediction.

ISSN:1062-936X    

DOI:10.1080/10629369908039109

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Toxicities of ten organophosphorus (OP) insecticides were measured against midge larvae (Chironomus riparius) under varying temperature (11, 18, and 25°C) and pH (6, 7, and 8) conditions and with and without sediment. Toxicity usually increased with increasing temperature and was greater in the absence of sediment. No trend was found with varying pH. A series of unidimensional parameters and multidimensional models were used to describe the changes in toxicity. LogKowwas able to explain about 40–60% of the variability in response data for aqueous exposures while molecular volume and aqueous solubility were less predictive. Likewise, the linear solvation energy relationship (LSER) model only explained 40–70% of the response variability, suggesting that factors other than solubility were most important for producing the observed response. Molecular connectivity was the most useful for describing the variability in the response. In the absence of sediment,1χvand3κ were best able to describe the variation in response among all compounds at each pH (70–90%). In the presence of sediment, even molecular connectivity could not describe the variability until the partitioning potential to sediment was accounted for by assuming equilibrium partitioning. After correcting for partitioning, the same molecular connectivity terms as in the aqueous exposures described most of the variability, 61–87%, except for the 11°C data where correlations were not significant. Molecular connectivity was a better tool than LSER or the unidimensional variables to explain the steric fitness of OP insecticides which was crucial to the toxicity.

ISSN:1062-936X    

DOI:10.1080/10629369908039110

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

We consider the construction of optimal molecular descriptors for characterization of the C˭C bond in alkenes. In particular we consider the use of path numbers and weighted path numbers as molecular descriptors and molar refraction as the molecular property on which the new descriptors are tested.

ISSN:1062-936X    

DOI:10.1080/10629369908039111

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Literature data on the toxicity of chlorophenols for three luminescent bacteria (Vibrio fischeri, and thelux-markedPseudomonas fluorescens10586spUCD607 andBurkholderia spp. RASC c2 (Tn4431)) have been analysed in relation to a set of computed molecular physico-chemical properties. The quantitative structure-toxicity relationships of the compounds in each species showed marked differences when based upon semi-empirical molecular-orbital molecular and atom based properties.

ISSN:1062-936X    

DOI:10.1080/10629369908039112

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1062-936X    

DOI:10.1080/10629369908039113

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:1062-936X    

DOI:10.1080/10629369908039108

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor