Quantitative structure-activity relationships , applied

PW91 (Perdew, Wang 1991) a gradient corrected DFT method QCI (quadratic conhguration interaction) a correlated ah initio method QMC (quantum Monte Carlo) an explicitly correlated ah initio method QM/MM a technique in which orbital-based calculations and molecular mechanics calculations are combined into one calculation QSAR (quantitative structure-activity relationship) a technique for computing chemical properties, particularly as applied to biological activity QSPR (quantitative structure-property relationship) a technique for computing chemical properties... 

BT Luke. Evolutionary programming applied to the development of quantitative structure-activity relationships and quantitative structure-property relationships. J Chem Inf Comput Sci 34(6) I279-1287, 1994. 

More recently (2006) we performed and reported quantitative structure-activity relationship (QSAR) modeling of the same compounds based on their atomic linear indices, for finding fimctions that discriminate between the tyrosinase inhibitor compounds and inactive ones [50]. Discriminant models have been applied and globally good classifications of 93.51 and 92.46% were observed for nonstochastic and stochastic hnear indices best models, respectively, in the training set. The external prediction sets had accuracies of 91.67 and 89.44% [50]. In addition to this, these fitted models have also been employed in the screening of new cycloartane compounds isolated from herbal plants. Good behavior was observed between the theoretical and experimental results. These results provide a tool that can be used in the identification of new tyrosinase inhibitor compounds [50]. 

Among the possible alternative methods, in vitro assay (for ATMs) and quantitative structure-activity relationships (QSARs) models (for ANTMs) are the most applied approaches in the toxicological and ecotoxicological evaluation of chemicals profiles, even in the field of environmental research and risk assessment. 

D-QSAR Three-dimensional quantitative structure-activity relationships lUPAC International Union of Pure and Applied Chemistry... 

Methods for Applying the Quantitative Structure-Activity Relationship Paradigm... 

Israels, A.Z. Applied Stochastic Models and Data Analysis 1986, 2, 121-130. Johnels, P. Gilner, M. Norden, B. Toftgard, R. Gustafsson, Quantitative Structure-Activity Relationships 1989, 8, 83-89. 

Quantitative Structure—Activity Relationships (QSAR). Quantitative Structure—Activity Relationships (QSAR) is the name given to a broad spectmm of modeling methods which attempt to relate the biological activities of molecules to specific structural features, and do so in a quantitative manner (see Enzyme inhibitors). The method has been extensively applied. The concepts involved in QSAR studies and a brief overview of the... 

Quantitative structure-activity relationships (QSARs) are important for predicting the oxidation potential of chemicals in Fenton s reaction system. To describe reactivity and physicochemical properties of the chemicals, five different molecular descriptors were applied. The dipole moment represents the polarity of a molecule and its effect on the reaction rates HOMo and LUMO approximate the ionization potential and electron affinities, respectively and the log P coefficient correlates the hydrophobicity, which can be an important factor relative to reactivity of substrates in aqueous media. Finally, the effect of the substituents on the reaction rates could be correlated with Hammett constants by Hammett s equation. 

Methods to predict the hydrolysis rates of organic compounds for use in the environmental assessment of pollutants have not advanced significantly since the first edition of the Lyman Handbook (Lyman et al., 1982). Two approaches have been used extensively to obtain estimates of hydrolytic rate constants for use in environmental systems. The first and potentially more precise method is to apply quantitative structure/activity relationships (QSARs). To develop such predictive methods, one needs a set of rate constants for a series of compounds that have systematic variations in structure and a database of molecular descriptors related to the substituents on the reactant molecule. The second and more widely used method is to compare the target compound with an analogous compound or compounds containing similar functional groups and structure, to obtain a less quantitative estimate of the rate constant. 

The quantitative structure-activity relationship (QSAR) model is by definition a model. Any model, such as animal model (also called in vivo) or in vitro model, is a system that applies to a specific situation, and thus, it is useful to study, evaluate, or assess a more complex system, which cannot be used experimentally for investigation. Thus, any model is a simplification of the target object of the study, and the model is useful for this or not depending on its purpose. It is also possible to imagine a series of models, each addressing one or more features of the more complex system. 

Quantitative Structure-Activity Relationships (QSARs) in the European REACH System Could These Approaches be Applied to Nanomaterials ... 

The prediction of toxicity through the use of quantitative structure-activity relationships ([Q]SAR) is the most basic of effect extrapolations and is applied when no toxicity or response data have been measured for the substances in question. (Q)SAR... 

Ambrose Amin E, Welsh WJ (2001) Three-dimensional quantitative structure-activity relationship (3D-QSAR) models for a novel class of piperazine-based stromelysin-1 (MMP-3) inhibitors applying a divide and conquer strategy. J Med Chem 44 3849-3855... 

These efforts were guided by the study of quantitative structure-activity relationships (QSAR) following the Hansch approach. In this method linear free-energy related and other electronic, hydrophobic, and steric substituent constants are used for a quantitative analysis of the possible ways in which substituents may modulate bioactivity in a congeneric series. In the QSAR studies of benzoylphenyl ureas the electronic Hammett a-constants and the hydro-phobic Hansch n-constants were used. To measure the steric influences, steric substituent constants of a new type (B1,B2,B3,B4, and L) were applied which had recently been introduced by us and which give improved correlations in comparison with the steric Es constants used in the literature hitherto (21, 22). The constants B- toBj are measures of the widths of substituents in four rectangular directions. The L-constant accounts for the length of a substituent ... 

Abraham MH, Hassanisadi M, Jalali-Heravi M et al. (2003) Draize rabbit eye test compatibility with eye irritation thresholds in humans a quantitative structure-activity relationship analysis. Toxicol Sci 76 384-391 Curren RD, Harbell JW (1998) In vitro alternatives for ocular irritation. Environ Health Perspect 106, Suppl 2 485M92 Draize JH, Woodard G, Calvery HO (1944) Methods for the study of irritation and toxicity of substances applied topically to the skin and mucous membranes. J Pharmacol Exp Ther 82 377-390... 

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