نتایج جستجو برای: quantitative structure property relationships qspr

تعداد نتایج: 2151093  

Journal: :Annali di chimica 2007
Jahanbakhsh Ghasemi Shahin Ahmadi

Quantitative structure-property relationship (QSPR) analysis has been directed to a series of pure nonionic surfactants containing linear alkyl, cyclic alkyl, and alkey phenyl ethoxylates. Modeling of cloud point of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and partial least squares (PLS) regression. In this study,...

2010
Jiwei Hu Xiaoyi Zhang Zhengwu Wang

This paper presents a review on recent progress in quantitative structure-property relationship (QSPR) studies of surfactants and applications of various molecular descriptors. QSPR studies on critical micelle concentration (cmc) and surface tension (gamma) of surfactants are introduced. Studies on charge distribution in ionic surfactants by quantum chemical calculations and its effects on the ...

2014
Rudolf Kiralj

Sign change problem (SCP) in multivariate Quantitative Structure-Activity/Property Relationships (QSAR/QSPR) is the inconsistency in the direction of association between molecular descriptors and the dependent variable. Sign change is observed when the signs of the elements of the reference vector (correlation vector for the data set obtained from variable selection) are compared to the signs o...

1999
David A. Gallagher

THE PHYSICAL AND chemical properties of a compound are a function of its molecular structure. Structure-property relationships are developed by finding one or more molecular descriptors that explain variations in the physical or chemical properties of a group of congeners/analogs. While some descriptors can be determined experimentally, deriving them from either the two-dimensional (2-D) or thr...

Journal: :Journal of chemical information and computer sciences 1998
Matthew D. Wessel Peter C. Jurs John W. Tolan Steven M. Muskal

The absorption of a drug compound through the human intestinal cell lining is an important property for potential drug candidates. Measuring this property, however, can be costly and time-consuming. The use of quantitative structure-property relationships (QSPRs) to estimate percent human intestinal absorption (%HIA) is an attractive alternative to experimental measurements. A data set of 86 dr...

Journal: :Computers & Chemical Engineering 2007
Alan R. Katritzky Svetoslav H. Slavov Dimitar A. Dobchev Mati Karelson

A novel QSPR development technique is proposed with the aim to combine the advantages of the two methods most frequently applied. A quantitative structure-property relationship (QSPR) is developed using this technique to relate the molecular structures of 645 diverse organic compounds to their vapor pressures at 25 C expressed as logVP. The compounds are encoded with topological, electronic, ge...

Journal: :International Journal of Molecular Sciences 2009
Lars Carlsen

The often observed scarcity of physical-chemical and well as toxicological data hampers the assessment of potentially hazardous chemicals released to the environment. In such cases Quantitative Structure-Activity Relationships/Quantitative Structure-Property Relationships (QSAR/QSPR) constitute an obvious alternative for rapidly, effectively and inexpensively generatng missing experimental valu...

1999
P. Gramatica N. Navas

Different sets of molecular descriptors using the k-nearest neighbor classi¢cation method were used to make a general classi¢cation of 152 organic solvents, the classi¢cation being further improved by performing the counterpropagation arti¢cial neural network. An extensive investigation was made of the physico-chemical properties of 152 solvents in a search for quantitative structure^property r...

Journal: :International Journal of Molecular Sciences 2002

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