330 research outputs found
Gramatica românească
No full textGramatica românească / alcătuită de Radu Tempea. - Sibiu : în tipografia lui Petru Bart, 1979. - [8] f., 218 p., [1] f. : frontisp., vig. ; 17,5 cm.
Text în limba română cu caractere chirilice. - Însemnări
Principles of QSAR Modeling
No full textAt the end of her academic career, the author summarizes the main aspects of QSAR modeling, giving comments and suggestions according to her 23 years’ experience in QSAR research on environmental topics. The focus is mainly on Multiple Linear Regression, particularly Ordinary Least Squares, using a Genetic Algorithm for variable selection from various theoretical molecular descriptors, but
the comments can be useful also for other QSAR methods. The need for rigorous validation, also external, and for applicability domain check to guarantee predictivity and reliability of QSAR models is particularly highlighted. The commented approach is the “predictive” one, based on chemometrics, and is usefully applied to the prioritization of environmental pollutants. All the discussed points and
the author’s ideas are implemented in the software QSARINS, as a legacy to the QSAR community
Gramatica românească pentru îndreptarea tinerilor
No full textGramatica românească pentru îndreptarea tinerilor / acum întâia oară lucrată prin Constantin Diaconovici Loga. - Buda : în Crăiasca Tipografie a Universităţii Ungarii, 1822. - [8] f., 206 p., [5] f. ; 20 cm.
Text în limba română cu caractere chirilice. - Însemnăr
WHIM descriptors of shape
No full textWHIM descriptors are 3D structural descriptors obtained from the (x,y,z)-atomic coordinates of a molecular conformation of a chemical, and are used successfully in QSAR modelling. They are built in so as to capture relevant 3D information regarding different features of molecular structure: size, shape, symmetry and atom distribution.
Different weights are used to obtain particular information for each set of descriptors.
Recently, some doubts have been raised in the literature regarding the ability of Weighted
Holistic Invariant Molecular (WHIM) descriptors of shape (the K non-directional WHIM descriptors) to describe the difference between linear and non-linear molecules. A data set of seventy aliphatic and aromatic chemicals of different shape (linear and branched
congeners) has been studied here, and is represented by K descriptors (global nondirectional WHIM descriptors of shape) based on different weights. The K descriptors range from 0 for a spherical molecule to 1 for a perfectly linear molecule. The present
study confirms the findings, already reported by the author, that the WHIM descriptors of shape (K) are unequivocally able to differentiate linear and non-linear molecules
Distribuzione di metalli pesanti in suoli e muschi di Piemonte e Sicilia: analisi mediante metodi chemiometrici
No full textOrganic pollutants environmental fate:modelling and prediction of global persistence by molecular descriptors
No full text- …
