Abductive networks: generalization, pattern recognition, and prediction of chemical behavior

1993 ◽  
Vol 71 (11) ◽  
pp. 1800-1804 ◽  
Author(s):  
John L.E. Campbell ◽  
Keith E. Johnson

Using commercially available software, it is possible to reduce numerical data to a mathematical representation called an abductive network (AN). In the current communication, we describe several simple examples which illustrate the interesting, and potentially useful properties of abductive networks. We show that when applied to the correlation of Kovats indices with molecular refractivities and dipole moments of substituted phenols, abductive networks more accurately predict Kovats indices than do counter-propagation neural networks or linear regression equations. When applied to the modeling of quantitative structure–activity relationships (QSAR) for local anesthetics, AN's are marginally superior to regression. AN's offer the advantage that correlations may be drawn between variables which are not easily related within a mathematical context.

1995 ◽  
Vol 30 (3) ◽  
pp. 324-332 ◽  
Author(s):  
Albert B. DeMilo ◽  
Richard W. Miller ◽  
Barna Bordás ◽  
Robert E. Redfern ◽  
Giles Mills

Larvicidal activity of a congeneric set of N-2-halo- (and 2,6-dihalo) benzoyl-N-phenylureas were determined in in vivo tests against the lesser mealworm, Alphitobius diaperinus (Panzer). Substituent modifications were made in both the benzoyl and anilide portions of the molecule. Linear regression analysis was used to derive quantitative structure-activity relationships (QSAR) from LC50 and LC99 values and a series of physicochemical substituent parameters. The analysis resulted in two significant single parameter regression equations selecting Hammett σp constant as the only relevant chemical descriptor and rejecting the other descriptors as insignificant. Penfluron and 2,6-difluoro-N-[[[4-(trifluoromethoxy) phenyl]amino]carbonyl]benzamide were potent larvicides in these tests and exceeded the effectiveness of diflubenzuron and triflumuron.


1986 ◽  
Vol 51 (1) ◽  
pp. 241-248 ◽  
Author(s):  
Miroslav Polster ◽  
Bohuslav Rittich ◽  
Renata Žaludová

The present work deals with the relationship between biological activities of differently substituted phenols and their physico-chemical parameters expressing the influence of hydrophobic, electronic and steric factors. The testing was performed with the fungi Trychophyton gypseum and Trychophyton gypseum var. Kaufman-Wolf and the yeast Candida albicans. Significant relationship between biological activity and pKA values was calculated. The interactions between individual factors as well as the influence of the position of substituents on quantitative structure-activity relationships are discussed.


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