QSARs were derived for 103 analogues of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), a potent inhibitor of the HIV-1 reverse transcriptase (RT). The activity of these compounds was investigated by means of multiple linear regression (MLR) and artificial neural network (ANN) techniques. Considering the relevant descriptors obtained from the MLR, a correlation coefficient of 0.92 (n = 95) was obtained with a 4-5-1 ANN model. The contribution of each descriptor to the structure-activity relationships was evaluated. The results showed that the anti-HIV activity of HEPT derivatives was strongly dependent on hydrophobic character and also steric factors of substituents.

Oxidative stress induced by nickel sulfide appears to cause loss of p16 and activation of MAP kinase signaling. These findings support the hypothesis of synergistic interactions between MAP kinase activation and p16 loss in carcinogenesis.

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Fuzzy logic has been used as a tool in structure-camphoraceous odor relationships. The data base studied included 99 molecules. The rules used to discriminate between camphor and non camphor molecules lead to 77% correct discrimination. Such rules account for the shape and the size of the molecule. Their adjustment by means of genetic algorithms led to 84% correct discrimination between camphor and non-camphor molecules. [figure: see text]. Membership function for the chosen variables.