Relation structure/ facteur acentrique d'alcools et de phénols: approche algorithme génétique – régression linéaire multiple

Les facteurs acentriques de 18 composés hydroxylés (alcools, phénols), ont été corrélés linéairement avec 2 descripteurs moléculaires de type géométrique sélectionnés par algorithme génétique, parmi plus de 1600 calculés en utilisant le logiciel de modélisation moléculaire DRAGON. Les différentes statistiques établies (coefficient de détermination multiple et de prédiction ; racines des erreurs quadratiques moyennes ; test de randomisation) montrent la qualité, la robustesse et les bonnes capacités prédictives internes du modèle construit. Aucune observation aberrante ou influente n’a été relevée.Mots clés: Alcools et phénols – Représentation numérique de la structure chimique – Facteur acentrique – Régression linéaire multiple – Modèle RSP hybrideEnglish Title: Structure / acentric factor relationship of alcohols and phenols: genetic algorithm – multiple linear regression approachEnglish AbstractThe acentric factors of 18 hydroxy compounds (alcohols, phenols) were linearly correlated with 2 molecular descriptors of geometrical type selected by genetic algorithm, among more than 1600 derived from the molecular modeling software DRAGON. The different statistics calculated (multiple determination and prediction coefficients; roots of the mean quadratic errors; Y-scrambling) show the quality, the robustness and the good internal predictive capacity of the constructed model. No outliers or influential observation was found.Keywords: Alcohols and phenols – Numerical representation of chemical structure – Acentric factor – Multiple linear regression – Hybrid SPR mode

Modeling Retention Indices of a Series Components Food and Pollutants of the Environment: Methods; OLS, LAD

The gas chromatographic retention indices for 89 pyrazines of test and 25 of validation on O V-101 and Carbowax -20M are successfuty modeled with the ald of a computer and the Software system Structural descriptors are calculated and multiple linear regression analysis are used to generate model equations relating structural features to observed retention characteristics then was treated with two methods The detection of influential observations for the standard least squares regression model is a problem which has been extensively studied LAD regression diagnostics offers alternative dicapproaches whose main feature is the robustness Here a nonparametric method for detecting influential observations is presented and compared with other classical diagnostics methods Comparisons are between models generated for the two stationary was carried out with two methods and descriptors that may encode differences in solute interactions with stationary phases of differing polarity are discussed and validated results in the state approached by the tests statistics Test of Anderson-Darling shapiro-wilk Agostino Jarque-Bera and the confidence interval thanks to the concept of robustness to check if the distribution of the errors is really approximat

Modeling Retention Indices of a Series Components Food and Pollutants of the Environment: Methods; OLS, LAD

The gas chromatographic retention indices for 89 pyrazines of test and 25 of validation on O V-101 and Carbowax -20M are successfuty modeled with the ald of a computer and the Software system Structural descriptors are calculated and multiple linear regression analysis are used to generate model equations relating structural features to observed retention characteristics then was treated with two methods The detection of influential observations for the standard least squares regression model is a problem which has been extensively studied LAD regression diagnostics offers alternative dicapproaches whose main feature is the robustness Here a nonparametric method for detecting influential observations is presented and compared with other classical diagnostics methods Comparisons are between models generated for the two stationary was carried out with two methods and descriptors that may encode differences in solute interactions with stationary phases of differing polarity are discussed and validated results in the state approached by the tests statistics Test of Anderson-Darling shapiro-wilk Agostino Jarque-Bera and the confidence interval thanks to the concept of robustness to check if the distribution of the errors is really approximat

Etude de la diffusion du dioctylphtalate du P V C plastifié trempé dans du n-heptane

Le transfert de D O P du PVC plastifié dans le n-Heptane liquide a été étudié en fonction des paramètres : concentration de D O P entre 35,5 et 50 % ; température entre 30 et 55 °C. L'agitation de la solution est importante, ainsi que la concentration en D O P du P V C, alors que l'influence de la température est négligeable. La cinétique du transfert dans la solution peut être représentée par la diffusion en régime transitoire. Le coefficient de diffusion est égal à 0,87.10–7 cm2/s lorsque le pourcentage de D O P est égal à 35,5 %

QSPR study of the water solubility of a diverse set of agrochemicals: hybrid (GA/ MLR) approach

A quantitative structure- property relationship (QSPR) was performed for the  prediction of the aqueous solubility of pesticides belonging to four chemical classes: acid, urea, triazine, and carbamate. The entire set of 77 pesticides was  divided into a training set of 58 pesticides and a test set of 19 pesticides according to the Snee technique. A six descriptor model, with squared correlation coefficient  (R2) of 0.8895 and standard error of estimation (s) of 0.52 log unit, was developed  by applying multiple linear regression analysis using the ordinary least square  regression method and genetic algorithm- variable subset selection. The reliability of the proposed model was further illustrated using various evaluation techniques:  leave- one- out cross- validation, bootstrap, randomization tests, and validation through the test set.Key Words: pesticides- aqueous solubility- QSPR- molecular descriptors- multiple  linear regression. Etude QSPR de la solubilité aqueuse d'un ensemble de divers produitsagrochimiques: approche hybride (AG/RLM)Une relation quantitative structure-propriété (QSPR) a été réalisée pour la prédiction de la solubilité aqueuse despesticides appartenant aux quatre classes chimiques: acide, urée, triazine, et carbamate. L'ensemble des 77pesticides a été divisé en un ensemble de calibrage de 58 pesticides et un ensemble de test de 19 pesticides selonla technique de Snee. Un modèle de six descripteurs, avec un coefficient de corrélation (R2) de 0,8895 et uneerreur standard d'estimation (s) de 0,52, a été développé en appliquant une analyse de régression linéaire multipleen utilisant la méthode de régression des moindres carrés ordinaires et les algorithme-génétiques pour lasélection des sous-ensembles de variables. La fiabilité du modèle proposé a été en outre illustrée en utilisantdiverses techniques d'évaluation: validation croisée par leave- one- out, bootstrap, tests de randomisation, et lavalidation par l'ensemble de test.Mots clés: pesticides- solubilité aqueuse- QSPR- descripteurs moléculaires- régression linéaire multiple

Pharmacological Molecule Based on Nanocarbon Container Encapsulated Ferromagnet by Combustion Synthesis for Cancer Therapy

Abstract Combustion synthesis in electrothermal explosion mode can be regarded as an efficient method to obtain new nanomaterials. Different starting mixtures of magnesium powder with various carbonates (Li 2 CO 3 , Na 2 CO 3 , CaCO 3 , FeCO 3 , (NH 4 ) 2 CO 3 ) were tried and the self-thermal reactions were carried out under both reactive (air) and neutral atmosphere (argon) with an initial pressure of 10 atm to yield novel nanomaterials. Fe, Co, Ni, Pd, Nd, Ta, Ti, Nb, W and NiO powders were used as catalysts and their synthesis and purification have been optimized. Under the applied conditions the presence of crystalline MgO and NaO 2 in products confirmed by XRD analysis, even for the reaction under neutral atmosphere, points to the deep conversion of carbonates. For producing fibrous products the Na 2 CO 3 system proved to be the most promising one. FESEM images show the morphology of the products with some 1-D nanostructures resembling carbon nanotubes and nanosized metal/carbon composite (carbon-encapsulated metal-based iron nanoparticles with a core-shell structure with interesting magnetic properties by combustion was obtained. Different magnetic metals (Fe, Ni, and Co) that can be encapsulated by the carbon shell, graphite layers and nanofibers. After purification procedure, we will only obtain core-shell or graphite layers encapsulated by metal magnetic nanoparticles without impurity like noncoated iron or carbides and amorphous carbon. The characterization techniques include the chemical analysis, HRTEM, XRD and FESEM.. The obtained novel pharmacological molecular nanostructure will be injected in the cancer tumor cell (prostate) after sterilization. The nanocontainer will be heated by microwave at the Laboratory Central of Anatomie and Cytology Pathology of the CHU Annaba. The reaction will be observed in the HRTEM