Entity

Time filter

Source Type

Batna, Algeria

Benounis M.,University of Khenchela | Benounis M.,University of Guelma
Sensors and Actuators, B: Chemical | Year: 2015

A new phosphate-selective poly[vinylchloride-co-vinylacetate-co-vinylalcohol] membrane with Trioctyl-tin-chloride (Carrier I) and Methylenebis[dibromo(phenyl)stannane] (carrier II) were proposed to invert the Hofmeister behaviour and to form strong complexes with the hydrophilic target anion. Plasticizers effect and selectivities for phosphate over many common anions, such as nitrate, chloride, fluoride and bicarbonate, at pH 3.6 are studied for several membranes formulations. We show that the phosphate selectivity is better and comparable to required values for membranes based on tin compound plasticized with low dielectric constant solvent and the sensor exhibits a LOD of about 6.5 × 10-08 M with a linear response towards phosphate ion over a wide concentration range of 10-5-10-3 M. The response times and lifetime of copolymer-membranes-optodes were studied. The response times of the membranes with copolymer based on carriers I and II were 20 s and 40 s, when changing from 10-4 M phosphate to 10-3 M. The lifetime of the copolymer-based-membrane was higher than that of PVC-based-membrane with the same carrier and the optode is adequate for phosphate ion detection in real water. © 2015 Elsevier B.V. All rights reserved. Source


Boudjemaa K.-E.,University of Mentouri Constantine | Boudjemaa K.-E.,University of Khenchela | Guenouche M.,University of Mentouri Constantine | Zouzou S.R.,University of Mentouri Constantine
General Relativity and Gravitation | Year: 2011

We compute the time delay of strong lensing in the framework of the Einstein-Straus solution in presence of a cosmological constant and restrict ourselves to the case of a spatially flat universe. The calculations are done to first order in the ratio of Schwarzschild radius to peri-lens. We apply our results to the lensed quasar SDSS J1004+4112. Our predictions for the time delay between the images C and D of the quasar range from 6 to 13years and are compatible with the experimental lower bound. © 2011 Springer Science+Business Media, LLC. Source


Hemam M.,University of Khenchela | Hemam M.,University of Mentouri Constantine | Boufaida Z.,University of Mentouri Constantine
International Journal of Reasoning-based Intelligent Systems | Year: 2011

Domain ontologies are intended to provide a commonly shared understanding among several user communities. Concepts and their relationships are used to explicitly model the realworld phenomena that are of interest to users of specific domain. In practice, a set of a specificdomain applications use different representations of the same real-world entity due to various viewpoints, context and specific interest. In this paper, we are interested in the problem of representing an ontology in heterogeneous organisation by taking into account different viewpoints and different terminologies of various users, groups or even communities in the organisation. Such ontology, called Multi-Viewpoints Ontology, allows heterogeneity and consensus in a heterogeneous organisation. So, our goal is to propose a Multi-Viewpoints Ontology Web Language, which is an extension of OWL-DL language, to allow the multiviewpoints ontologies representation for the Semantic Web. Copyright © 2011 Inderscience Enterprises Ltd. Source


Derouiche F.,University of Mentouri Constantine | Derouiche F.,University of Khenchela | Bole-Feysot C.,University of Rouen | Naimi D.,University of Mentouri Constantine | Coeffier M.,University of Rouen
Biochemical and Biophysical Research Communications | Year: 2014

Background and aims Hyperhomocysteinemia (HHcy) is associated with cardiovascular diseases and is thought to induce endogenous oxidative stress and causes many cellular damages. Proteasome that degrades oxidized and ubiquitinated proteins can regulate the cellular response to oxidative stress. We aimed to investigate whether hyperhomocysteinemia induces oxidative stress and alters proteasome function and composition in heart and aorta tissues of rat. Methods and results To create hyperhomocysteinemia, male Wistar rats (Pasteur Institute-Algiers) were received daily intraperitoneal injections of dl-homocysteine (0.6-1.2 μM/g body weight) for 3 weeks. Biomarkers of oxidative stress (malondialdehyde (MDA), protein carbonyl (PC), superoxide dismutase (SOD) and catalase (CAT)) were first measured by biochemical methods and tissue damages by histological sections. Proteasome activities were quantitated using fluorogenic synthetic peptides; ubiquitinated proteins and proteasome subunits expression were then evaluated by SDS PAGE and Western blot analysis. We showed increased MDA and PC but decreased SOD and CAT levels both in plasma, heart and aorta accompanied by histological changes. A significant decrease of proteasome activities was observed in heart, whereas proteasome activity was not affected in aorta. However proteasome composition was altered in both tissues, as the accumulation of ubiquitinated proteins. Conclusion Data demonstrated an alteration of the ubiquitin-proteasome system in hyperhomocysteinemia as a result of accumulating oxidized and ubiquitinated proteins in response to oxidative stress. Further studies must be conducted to better understanding mechanisms responsible of proteasome alterations in hyperhomocysteinemia. © 2014 Elsevier Inc. All rights reserved. Source


Fouad A.,University of Khenchela | Boukhetela D.,Polytechnic School of Algiers | Boudjema F.,Polytechnic School of Algiers
International Journal of Control and Automation | Year: 2013

A new type controller, recurrent fuzzy neural networks-fuzzy-sliding mode controller (FRNN-FSMC), is developed for a class of large-scale systems with unknown bounds of high-order interconnections and disturbances. The main purpose is to eliminate the chattering phenomenon and to overcome the problem of the equivalent control computation. The FRNN-FSMC, which incorporates the recurrent fuzzy neural network (RFNN), fuzzy logic controller (FLC) and the SMC, can eliminate chattering using a fixed boundary layer around the switch surface. Within the boundary layer, where the FLC is applied, the chattering phenomenon, which is inherent in a SMC, is avoided by smoothing the switch signal. Moreover, to compute the equivalent controller, a feed-forward RFNN is used. The stability of the whole system is analyzed via the Lyapunov methodology. In this study, we propose an effective method to select some key controller parameters in an optimal manner by using the genetic algorithm (GA), so that a high performance of the overall system's response can be achieved. The effectiveness and efficiency of the proposed controller and optimization method were tested using highly interconnected nonlinear systems as examples. Source

Discover hidden collaborations