CONTRIBUTION A L’ETUDE DE LA FORMATION DU SILICIURE DE TITANE Ti/Si(B), TiN/Ti/Si(B) MISE EN EVIDENCE D’UN MODELE THERMODYNAMIQUE

Dans les nouvelles technologies des circuits intégrés, il est nécessaire que la résistivité des interconnexions soit très faibles, laconcentration des dopants aux contacts siliciure/silicium détermine directement cette résistance. Parmi ces dopants il y al’arsenic et le bore qui se caractérisent par des comportements variés d’un siliciure à un autre.Dans ce travail nous allons suivre le comportement du bore implanté dans un substrat de silicium avant le dépôt de la couchemétallique. Le titane est un métal très réactif avec l’oxygène pour cela nous avons utilisé l’encapsulation. Nous faisons le pointquant à l’effet de l’encapsulation par rapport à des échantillon non encapsulés.Cette étude a été menée en recuit thermique rapide. L’analyse des échantillons se fait par le rétro diffusion des particules(RBS). Les résultats seront traité par un modèle basé sur la chaleur effective de formation ce modèle qui s’appliquer bien pourles siliciures pures (sans présence des dopants ou autres impuretés). Nous avons élaboré un modèle général qui tient comptedes impureté

Effects of Juglans regia Root Bark Extract on Platelet Aggregation, Bleeding Time, and Plasmatic Coagulation: In Vitro and Ex Vivo Experiments

Platelets have an important role in thrombosis and haemostasis. Hyperactivity of the platelets has been associated with thromboembolic diseases and represents the main cause of complications of cardiovascular diseases. Crude aqueous extract (CAE) of Juglans regia root bark was evaluated for bleeding time, antiaggregant activity by using agonists, thrombin, ADP, collagen, or arachidonic acid (in vitro and ex vivo), and anticoagulant activity by measuring the clotting parameters: activated partial thromboplastin time, prothrombin time, thrombin time, and fibrinogen dosage (in vitro and ex vivo). The result of this study reported that the strongest antiaggregant effect of CAE in vitro was observed on the ADP-induced aggregation with inhibitions up to 90 %, while, in ex vivo experiments, the inhibition (more than 80 %) was observed with all agonists. Anticoagulant effect of CAE significantly prolonged the TT and decreased the fibrinogen level in vitro and ex vivo without interfering with APTT and PT. The bleeding time in mice and rats was significantly increased by CAE. The antiplatelet and anticoagulant effect observed in this study suggest that Juglans regia could have antithrombotic and/or thrombolytic activities and provide an alternative therapy against thrombotic complications related to cardiovascular diseases

Natural product based composite for extraction of arsenic (III) from waste water

Abstract Natural based composites of hydroxyapatite/Gum Arabic designed for removal of toxic metal arsenic (III) from waste water were synthesized and evaluated. Several composites with various compositions were prepared by the wet chemical method and analyzed using various spectroscopic and analytical methods such as: Fourier transform infrared spectroscopy, total organic carbon production, XRD analysis and scanning electron microscope. The rates of weight loss and water absorption of the HAp/GA composites as a function of time were evaluated in phosphate-buffered saline solution at 37 °C and a pH of 7.4. The effects of several variables on adsorption of arsenic (III) by HAp/GA composites were evaluated. The variables include arsenic (III) concentration, contact time (t) and complex surface nature of HAp/GA composite. Three surface complexation models were used to study the mechanisms controlled the adsorption. The models were Langmuir, Freundlich and Dubinin Radushkevich. The adsorption kinetic of arsenic (III) on the composite surface was described by three modes: pseudo first order, pseudo second order and the intra particle diffusion. The results revealed that, the rate of adsorption of arsenic (III) by HAp/GA composites was controlled by two main factors: the initial concentration of arsenic (III) and the contact time. The kinetic studies also showed that, the rate of adsorption is a second order. The results indicate that, composite offered in this study could be a valuable tool for removing toxic metals for contaminated water by adsorption. Graphical abstract