Effect of heat treatment on bioelectronic coordinates and antibacterial activities of natural and synthetic clays

Our work consists in studying the effect of the thermal treatment at 900°C of three clays “two anionic clays of synthesis ' Double lamellar hydroxide' Zn3Al-CO3 and Mg3Al-CO3, and another natural cationic: Ghassoul (Gh)”, on their antibacterial and bioelectronic power. Their chemical characteristics such as pH at zero charge point (pHzcp), redox potential (Eh), index of oxidizing/reducing power (rH2), and electrochemical potential to dissipate energy (W), as well as the type of oxide formed as a result of this treatment; were also determined. The materials were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and scanning electron microscopy (SEM). Antibacterial activity was tested for four bacteria: two Gram positive (Staphylococcus aureus, Enterococcus faecalis) and two Gram negative (Escherichia coli, Salmonella spp). The antibacterial power of the three clays was evaluated by their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), using the microtiter plate technique. The results showed that the pHzcp, rH2, W and antibacterial power of the two lamellar double hydroxides increased as a result of heat treatment. While the test on the heat treated cationic clay showed an opposite result. It thus appears that the changes in the physicochemical and electrochemical characteristics of the clays following their calcination at 900°C; are at the origin of the change in their antibacterial powe

Critical Field Strength in an Electroclinic Liquid Crystal Elastomer

We elucidate the polymer dynamics of a liquid crystal elastomer based on the time-dependent response of the pendent liquid crystal mesogens. The molecular tilt and switching time of mesogens are analyzed as a function of temperature and cross-linking density upon application of an electric field. We observe an unexpected maximum in the switching time of the liquid crystal mesogens at intermediate field strength. Analysis of the molecular tilt over multiple time regimes correlates the maximum response time with a transition to entangled polymer dynamics at a critical field strength.Comment: 4 pages, 3 figure

Genetic and nongenetic effects on the number of ovarian follicles and oocyte yield and quality in the bovine local (Oulmes Zaer), exotic breeds and their crosses in Morocco

The effects of genetic and non genetic factors on the number of ovarian follicles and oocyte yield and quality in the bovine local breed (Oulmes Zaer), exotic breeds and their crosses in Morocco was investigated. In this study, females in very bad body conditions (BCS < 2) were not slaughtered and the average. The body condition scores (BCS) was 2.94 ± 0.89. Although some individual values were out of the normal ranges, mean values of total proteins, albumin, urea, &#946;-OH and GOT remain normal and were 77.83 ± 8.74 g/l, 32.4 ± 4.41g/l, 4.43 ± 2.13 mmol/l , 0.83± 0.48 mmol/l et 45.55 ± 11.95 UI/l, respectively. The mean number of ovarian follicles per cow (2-8 mm) was high (22.98 ± 8.41) whereas the oocyte yield (and 2.60 ± 1.53) was very low. The effects of genetic group, age and BCS on the number of follicles, oocyte yield and the quality were significant. Key Words: Cows, follicular population, oocyte yield and quality. African Journal of Biotechnology Vol.4(1) 2005: 9-1

Removing polyphenols contained in olive mill wastewater by membrane based on natural clay and Hydrotalcite Mg-Al

The purpose of this work is to study the performance of a membrane based on Ghassoul and Hydrotalcite (GHTM) in the retention of polyphenols (organic pollutants). This membrane was elaborated and characterized in our laboratory and was used in the filtration of olive mill wastewaters (OMW) of semi-modern unit of the olives. The choice of these materials depends essentially on their interesting properties (low cost, abundantly in nature and the ease of the preparation).The diluted OMW (40%, 60% and 80%) were very acidic with a pH between 5.29-5.64 and had a high concentration of polyphenols from 30-60mg/L. However, after treatment the permeate revealed a significant decrease in polyphenols of61% and a complete disappearance of brown coloration for 80% OMW.The results show that the membrane developed is efficient to remove the polyphenols and reduce the turbidity, COD and BOD5 of OMW

Solvent-free aldol condensation of furfural and acetone on calcined Mg-Al hydrotalcites

Une série de matériaux de type hydrotalcite Mg X Al-CO 3 , où X correspond au rapport molaire nominal Mg / Al (X: 2, 2,5, 3 et 3,5), ont été préparés et caractérisés par fluorescence X (XRF ), X - diffraction des rayons (XRD), spectroscopie infrarouge (FT-IR) et analyse thermique (TG-DTA). L'oxyde mixte (Mg X Al-O) avec un rapport Mg / Al de 3,5 dérivé de l'hydrotalcite calcinée à 450 ° C s'est avéré être le catalyseur optimal qui peut donner la basicité la plus élevée et la plus grande activité catalytique pour la condensation aldolique sans solvant du furfural et de l'acétone.L'activité des hydrotalcites de Mg-Al calciné pour cette réaction était corrélée à leur basicité telle que déterminée par l'adsorption de phénol. La meilleure conversion du furfural et la sélectivité du furfural-acétone (FA) ont été obtenues à 90 ° C après 2 heures sur le Mg 3,5 Al-O avec 98% de conversion et une sélectivité de 78% en (FA). L'activation pour la condensation d'aldol entre le furfural et l'acétone s'est avérée être de 24,8 KJ / mol en catalyze hétérogène avec des hydrotalcites de Mg-Al calciné par rapport à la valeur augmentée en catalyze homogène avec NaOH qui était de 55,8 KJ / mol

Problématique du contrôle et de la prévention de la coccidiose du poulet

La coccidiose chez le poulet est une pathologie digestive causée par les sept espèces du genre Eimeria dont les plus pathogènes sont: E. tenella, E. acervulina, E. brunetti et E. maxima. Le cycle de vie des coccidies est direct et très court souvent réalisé en sept jours et qui débouche sur laformation des oocystes excrétés à travers les fèces. L’incidence économique de la maladie est estimée à 2,3 milliards d’Euro mondialement avec 70% des pertes attribuables à la coccidiose sub-clinique, difficilement perceptible, qui déprime le gain de poids vif corporel et l’indice de consommation alimentaire du poulet. L’utilisation du PCR (Polymerase Chain Reaction) permet d’identifier les espècesde coccidies par l’analyse du génome. Les mesures de prévention et de contrôle sont basées sur l’utilisation des anticoccidiens et des vaccins. Toutefois, les problèmes de résistance des coccidies aux médicaments, la présence de résidus médicamenteux dans les produits avicoles et la forme sub-clinique de la maladie engendrée par la réplication des coccidies vaccinales dans les entérocytes, constituent de graves menaces pour la filière poulet. D’autres moyens de lutte continuent de faire l’objetd’expérimentation à travers les plantes médicinales, et les vaccins recombinés. L’utilisation de la résistance naturelle aux coccidies de certains génotypes de poulet est une perspective envisageable quipeut définitivement mettre l’aviculture à l’abri des pertes énormes engendrées par les mesures de contrôle actuelles et la forme sub-clinique de la maladie.Mots clés: Eimeria, anticoccidien, vaccin, plante médicinale, résistance naturelle

Orientational order of a ferroelectric liquid crystal with small layer contraction

We present spectroscopic and optical studies of a non-layer-shrinkage ferroelectric liquid crystal DSiKN65. The orientational order parameters S, measured with respect to the smectic layer normal using IR spectroscopy on a sample aligned homeotropically, does not exhibit any significant variation between the smectic-A* and smectic-C* phases. In contrast the birefringence of a planar homogenous sample abruptly increases at the smectic-A* to smectic-C* transition. This suggests a general increase in the orientational order, which can be described by the orientational order parameters S\u27 defined with respect to the director. Simultaneous increase of S\u27 and the director tilt θ may explain the low shrinkage of smectic layers, which is consistent with recent theoretical models describing the smectic-A* to smectic-C* transition for such materials

Recent colonization of the Galápagos by the tree Geoffroea spinosa Jacq. (Leguminosae)

This study puts together genetic data and an approximate bayesian computation (ABC) approach to infer the time at which the tree Geoffroea spinosa colonized the Galápagos Islands. The genetic diversity and differentiation between Peru and Galápagos population samples, estimated using three chloroplast spacers and six microsatellite loci, reveal significant differences between two mainland regions separated by the Andes mountains (Inter Andean vs. Pacific Coast) as well as a significant genetic differentiation of island populations. Microsatellites identify two distinct geographical clusters, the Galápagos and the mainland, and chloroplast markers show a private haplotype in the Galápagos. The nuclear distinctiveness of the Inter Andean populations suggests current restricted pollen flow, but chloroplast points to cross-Andean dispersals via seeds, indicating that the Andes might not be an effective biogeographical barrier. The ABC analyses clearly point to the colonization of the Galápagos within the last 160 000 years and possibly as recently as 4750 years ago (475 generations). Founder events associated with colonization of the two islands where the species occurs are detected, with Española having been colonized after Floreana. We discuss two nonmutually exclusive possibilities for the colonization of the Galápagos, recent natural dispersal vs. human introduction.Fil: Caetano S.. No especifíca;Fil: Currat M.. Universidad de Ginebra; SuizaFil: Pennington, R. T.. Royal Botanic Gardens; Reino UnidoFil: Prado, Darien Eros. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Departamento de Biología. Cátedra de Botánica Morfológica y Sistemática Agronómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Excoffier L.. University of Bern; SuizaFil: Naciri, Y.. No especifíca

Strain Analysis of a Chiral Smectic A Elastomer

We present a detailed analysis of the molecular packing of a strained liquid crystal elastomer composed of chiral mesogens in the smectic A phase. X-ray diffraction patterns of the elastomer collected over a range of orientations with respect to the X-ray beam were used to reconstruct the three-dimensional scattering intensity as a function of tensile strain. For the first time, we show that the smectic domain order is preserved in these strained elastomers. Changes in the intensity within a given scattering plane are due to reorientation, and not loss, of the molecular order in directions orthogonal to the applied strain. Incorporating the physical parameters of the elastomer, a nonlinear elastic model is presented to describe the rotation of the smectic-layered domains under strain, thus providing a fundamental analysis to the mechanical response of these unique materials.Comment: 28 Page

A supervised learning regression method for the analysis of oral sensitivity of healthy individuals and patients with chemosensory loss

The gustatory, olfactory, and trigeminal systems are anatomically separated. However, they interact cognitively to give rise to oral perception, which can significantly affect health and quality of life. We built a Supervised Learning (SL) regression model that, exploiting participants' features, was capable of automatically analyzing with high precision the self-ratings of oral sensitivity of healthy participants and patients with chemosensory loss, determining the contribution of its components: gustatory, olfactory, and trigeminal. CatBoost regressor provided predicted values of the self-rated oral sensitivity close to experimental values. Patients showed lower predicted values of oral sensitivity, lower scores for measured taste, spiciness, astringency, and smell sensitivity, higher BMI, and lower levels of well-being. CatBoost regressor defined the impact of the single components of oral perception in the two groups. The trigeminal component was the most significant, though astringency and spiciness provided similar contributions in controls, while astringency was most important in patients. Taste was more important in controls while smell was the least important in both groups. Identifying the significance of the oral perception components and the differences between the two groups provide important information to allow for more targeted examinations supporting both patients and healthcare professionals in clinical practice