Search

Studying the effects of heating, reheating and exposure to microwave radiation on the structure of five types of edible oils such as olive oil, corn oil, cotton seeds oil, supply oil and sunflower oils in which used two kilograms for each sample and were collected from the origin of production in the local market and considered as fresh oils. Studying the change in the structure of edible oils by nuclear magnetic resonance (NMR) spectra, describe ,in general, a number of regions which can be considered as a base line of comparison to differentiate the properties of fresh oils from that exposed to normal heating or exposure to microwave once or several times. The NMR results revealed changes in the chemical structures of the considered edible oils. The changes occurred in the function groups of the oils especially; the alylic region of the oil (between 1.93 – 2.13 ppm), the bis-alylic region (2.72 – 2.84 ppm), olefeinic region ( 5.2 – 5.4 ppm), hydroproxide region ( 5.9 – 7.2 ppm), and the aldehyde region ( 9.5 – 9.7 ppm). The changes in these regions, indicate degradation and the formation of new complex chemical structures as a result of normal heating. Negligible changes in the chemical structures of the considered oils occurred by microwave heating, this give an impression that microwave heating even with more exposure frequency does not induce any hazards i.e., the absence of aldehyde groups.

The present study was undertaken to investigate the effect of heating, reheating and exposure to microwave radiation on some biophysical and biochemical properties of edible oils. In homes and restaurants, vegetable oils used for cooking are usually heated to very high temperatures, and may be reused several times to save costs. The recycling process involves repetitive heating of the oils may be bad for health. In this study used four samples of edible oils such as olive oil, cotton seeds oil, supply oil and corn oils in which used two kilograms for each sample and were collected from the origin of production in the local market and considered as fresh oils. The biophysical results showed that viscosity, refractive index of edible oils increase with the increase of heating frequency, this increase is higher in case of normal heating than microwave heating, the color intensity increased with normal heating and decreased with microwave exposure. The biochemical results revealed that the saponification number, the acid and peroxide values increased with increasing frequency of heating by both methods and the iodine number decrease by increased heating by the two methods. From this results it is concluded that the normal heating for four times induced biophysical and biochemical changes that must be taken in consideration, using microwave exposure induces minor changes in biophysical and biochemical properties and the olive oil showed the lowest level of changes which may be due to its high content of monounsaturated fatty acids, which may be the reason of its least autoxidation of rancidity

Ciprofloxacin hydrochloride is a broad spectrum antibiotic, effective against various types of micro-organisms but its controlled release formulation is recommended due to its short biological half-life (4 hrs). It was the aim of the present work to prolong its release after administration. So, Ciprofloxacin HCl loaded Chitosan Nanoparticles were prepared by the ionic gelation method. Characterization and evaluation of the in vitro release of Chitosan Nanoparticles loaded with Ciprofloxacin hydrochloride were studied. The data of the study clearly demonstrated that, Ciprofloxacin HCl loaded Chitosan Nanoparticles were 60.175 ± 4.973 nm in size with almost 90.713 % Ciprofloxacin HCl encapsulation efficiency. The TEM micrographs showed that the Nanoparticles surface looked spherical or oval and Ciprofloxacin HCl incorporation increases size of Nanoparticles loaded with Ciprofloxacin HCl compared to the empty ones. In vitro release of Ciprofloxacin HCl from Ciprofloxacin HCl loaded CS Nanoparticles was determined in phosphate buffered saline (PBS, pH 7.4), and the data showed an initial burst release followed by slow sustained drug release rate (81.698 % within 24 hour ). These observations suggest that the Nanoparticles prepared by ionic gelation process without using harsh organic chemicals might be recommended as a controlled drug delivery systems to improve efficacy, reduce toxicity, and improve patient compliance.

Cette communication s’intéresse à la problématique du détourage des composites à renfort en fibres de verre (GFRP). Après avoir montré en quoi cette problématique est d’actualité, les objectifs du travail sont présentés. Puis les conditions expérimentales retenues (éprouvettes, machine, outils et stratégie d’usinage) sont décrites. Ensuite, différentes expérimentations sont détaillées. Les premiers essais, dits « de base », permettent de tester les conditions de coupe initialement préconisées pour différents outils et de comparer ceux-ci. Ils permettent aussi de comparer l’incidence de la direction d’usinage par rapport à l’orientation des fibres. Dans les essais suivants, l’incidence de l’évolution de deux paramètres de coupe autour de leurs valeurs de base (la vitesse de coupe Vc et l’avance par dent fz) sur la qualité de la surface détourée est étudiée.