Search results for: Abderraouf Messai

Authors: Boualem Mekimah, Abderraouf Messai, Abdelkrim Belhedri

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Dielectric substrates have an important attention in the fabrication of microstrip patch antennas. The effects of the uniaxial anisotropy and the loss tangent on resonant frequencies of microstrip patches consist of two perfectly conducting rectangular patches in stacked and offset configuration, embedded in a bilayer medium containing isotropic or uniaxial anisotropic materials. The Green’s functions are discussed in detail and numerical results are validated by comparing the computed results with previously published data. The numerical results show, that the uniaxial anisotropy has more effects on resonant frequencies according to the optical axis. However, the loss tangent of dielectric substrates has almost no effect on resonant frequencies, but it strongly affects the imaginary parts of the resonant frequencies of the antenna. The dielectric constant has no effect on the separation in terms of frequencies.

Keywords: resonant frequencies, loss tangent, microstrip patches, stacked, anisotropic materials, optical axis

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Authors: N. Messai, A. Boumali

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In this work, we aim to solve the two dimensional Kemmer equation including Dirac oscillator interaction term, in the background space-time generated by a cosmic string which is submitted to an uniform magnetic field. Eigenfunctions and eigenvalues of our problem have been found and the influence of the cosmic string space-time on the energy spectrum has been analyzed.

Keywords: Kemmer oscillator, cosmic string, Dirac oscillator, eigenfunctions

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Authors: Khouadjia Mohamed Lyes Kamel, Bensalem Sara, Abdou Kamel, Belkadi Ahmed Abderraouf, Kessal Oussama

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The experimental study was conducted on sediments dredging from the dam of Bni Haroun, the most important and the largest dam in Algeria. The first phase of the work was to substitution of crushed sand with sediments to study the workability and compressive strength of ordinary concretes. The second phase of the work is to study the behavior of concrete with sediment under the effect of the freeze-thaw cycles. The results showed that the mechanical performance of concretes with sediments is better with a substitution rate of 10%.

Keywords: sediments, concrete, dam, workability, compressive strength, freeze-thaw cycles

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Authors: Aymen Gammoudi, Hamza Labbaci, Nizar Messai, Yacine Sam

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Web Service Composition (Mash-up) has been considered as a new approach used to offer the user a set of Web Services responding to his request. These approaches can return a set of similar Mash-ups in a given context that makes users unable to select the perfect one. Recent approaches focus on computing the skyline over a set of Quality of Service (QoS) attributes. However, these approaches are not sufficient in a dynamic web service environment where the delivered QoS by a Web service is inherently uncertain. In this paper, we treat the problem of computing the skyline over a set of similar Mash-ups under certain dimension values. We generate dimensions for each Mash-up using aggregation operations applied to the QoS attributes. We then tackle the problem of computing the skyline under uncertain dimensions. We present each dimension value of mash-up using a frame of discernment and introduce the d-dominance using the Evidence Theory. Finally, we propose our experimental results that show both the effectiveness of the introduced skyline extensions and the efficiency of the proposed approaches.

Keywords: web services, uncertain QoS, mash-ups, uncertain dimensions, skyline, evidence theory, d-dominance

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Authors: Messai Amel, Badis Zakaria, Benali-Cherif Nourredine, Dominique Luneaub

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We are interested in molecular polymetallic species having high spin and nuclearities in relation to the field of so call single-molecule magnets (SMMs). The goal is to find a way to synthesis metal clusters which may have application in magnetism and nano sciences. With this purpose, we decided to investigate the coordination chemistry of the Schiff base. Along this way we were able to create cubane-like complexes and elaborate new Single Molecule-Magnets. The idea was to use Schiff base ligands and different metals to generate high nuclear complexes. Complexation of Shiff base with copper (II) has been investigated. Tetra nuclear complex with a cubane like core have been synthesized with (Sciff base), with the same base and cobalt (II) we obtain an other single magnetic complex completely different. In this presentation, we report the synthesis, crystal structure and magnetic properties of the tetranuclear compound (Cu4 L4), and the tetranuclear compound. (Co4L4)

Keywords: cluster-assembled materials, magnetic compounds, Sciff base, cupper, cobalt

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Authors: Bouchaïb Gazzaz, Hamid El Amri, Hind Dehbi, Abderraouf Hilali

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Medical cannabis has been cultivated and used in many countries around the world. The story of the use of cannabis as a therapeutic agent is difficult to trace, in particular, because the laws regulating its production, distribution, possession, and consumption are relatively recent. Nowadays, in countries where it is authorized, medical cannabis is used in a very wide variety of illnesses and pathologies, particularly in cancer cures. Presently, cannabinoid receptor agonists (like nabilone and dronabinol) are used for reducing chemotherapy induced vomiting. This review aims to discuss a recent finding on the use of therapeutic cannabis in patients with cancer. First, this work addresses the progress made in the use of cannabinoids as therapeutic agent and their application in the treatment of different types of cancer. Secondly, a detailed analysis of the pharmacogenetic aspect of cannabis will be discussed.

Keywords: cannabinoids, endocannabinoids system, cancer treatment, cannabinoid receptors, genetic polymorphism, pharmacogenomics

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Authors: Awatif Boumaza, Abderraouf Hilali, Hayat Talbi, Houda Sbayou

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The methanolic extract of Zygophyllum cornutun coss, an Algerian medicinal plant, was screened to the presence of mutagenic activity and genotoxic effect using the Ames test (Salmonella/microsome) and the micronucleus assay respectively. Positive results were obtained with both tests. The Ames test showed mutagenic activity in the presence of microsomal activation, while negative result was observed without microsomal activation. In the micronucleus test, two parameters were evaluated: the frequency of the micronucleus that increased in a dose dependent way and the proliferation index that decreased according to the micronucleus frequency. Even that further studies must be carried out, the mutagenic activity and the genotoxic effect of Zygophyllum cornutum should be taken in consideration when used as therapeutic plant.

Keywords: ames test, micronucleus test, mutagenic activity, genotoxicity, Zygophyllum cornutum

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Authors: Abderraouf Gaaloul, Faouzi Msahli

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The use of standard sliding mode controller, usually, leads to the appearing of an undesirable chattering phenomenon affecting the control signal. Such problem can be overcome using a higher-order sliding mode controller (HOSMC) which preserves the main properties of the standard sliding mode and deliberately increases the control smoothness. In this paper, we propose a new HOSMC for a class of uncertain multi-input multi-output nonlinear systems. Based on high gain and integral sliding mode paradigms, the established control scheme removes theoretically the chattering phenomenon and provides the stability of the control system. Numerical simulations are developed to show the effectiveness of the proposed controller when applied to solve a control problem of two water levels into a quadruple-tank process.

Keywords: nonlinear systems, sliding mode control, high gain, higher order

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Authors: Alouache Souhila, Messai Yamina, Torres Carmen, Bakour Rabah

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Objective: It has often been reported an association between antibiotic resistance and virulence. However, resistance to quinolones seems to be an exception, it tends instead to be associated with an attenuation of virulence, particularly in clinical strains. The purpose of this study was to evaluate the potential virulence of 28 quinolone-resistant E. coli strains recovered from water at the inflow (n=16) and outflow (n=12) of an urban wastewater treatment plant (WWTP). Methods: E. coli isolates were selected on Tergitol-7 agar supplemented with 2µg/ml of ciprofloxacin, they were screened by PCR for 11 virulence genes related to Extraintestinal pathogenic E. coli (ExPEC): papC, papG, afa/draBC, sfa/foc, kpsMTII, iutA, iroN, hlyF, ompT, iss and traT. The phylogenetic groups were determined by PCR and clonal relationship was evaluated by ERIC-PCR. Results: Genotyping by ERIC-PCR showed 7 and 12 DNA profiles among strains of wastewater (inflow) and treated water (outflow), respectively. Strains were assigned to the following phylogenetic groups: B2 (n = 1, 3.5%), D (n = 3, 10.7%), B1 (n = 10, 35.7%.) and A (n = 14, 50%). A total of 8 virulence-associated genes were detected, traT (n=19, 67.8%), iroN (n= 16, 57 .1%), hlyF (n=15, 53 .5%), ompT (n=15, 53 .5%), iss (n=14, 50%), iutA (n=9, 32.1%) , sfa/foc (n=7, 25%) and kpsMTII (n=2, 7.1%). Combination of virulence factors allowed to define 16 virulence profiles. The pathotype APEC was observed in 17.8% (D=1, B1=4) and human ExPEC in 7% (B2=1, D=1) of strains. Conclusion: The study showed that quinolone-resistant E. coli strains isolated from wastewater and treated water in WWTP harbored virulence genes with the presence of APEC and human ExPEC strains.

Keywords: E. coli, quinolone-resistance, virulence, WWTP

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Authors: Alya Harichane, Abderraouf Achour, Abdelbaki Benmounah

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The main difficulty encountered in the formulation of high-performance concrete (HPC) consists in choosing the most efficient cement-superplasticizer pair allowing to obtain maximum water reduction, good workability of the concrete in the fresh state, and very good mechanical resistance in the hardened state. The aim of this work is to test the efficiency of three polycarboxylate ether-based superplasticizers (PCE) marketed in Algeria with CEMI 52.5 R cement and to study the effect of chemical structure of PCE on zeta potential, rheological and mechanical properties of cement pastes. The property of the polymers in cement was tested by a Malvern Zetasizer 2000 apparatus and VT 550 viscometer. Results showed that the zeta potential and its rheological properties are related to the molecular weight and the density carboxylic of PCE. The PCE with a moderate molecular weight and the highest carboxylic groups had the best dispersion (high value of zeta potential) and lowest viscosity. The effect of the chemical structure of PCEs on mechanical properties is evaluated by the formulation of cement mortar with these PCEs. The result shows that there is a correlation between the zeta potential of polymer and the compressive strength of cement paste.

Keywords: molecular weight, polycarboxylate-ether superplasticizer, rheology, zeta potential

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Authors: Sana El Adlani, Yassir Ait Ben Kaddour, Abdelhafid Benksim, Abderraouf Soummani, Mohamed Cherkaoui

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Background: Infertility in all countries of the word is on an increase, it’s why the World Health Organization included an investigation into young people's fertility. In this sense, it’s important to increase efforts to improve the knowledge about fertility for the young population. The aim of this study is to describe the difference between knowledge and attitude of medical and non-medical Moroccan young people. Materials and Methods: 100 medical Moroccan students (group 1) participated in the study, between 18 and 30 years, by a simple random sampling method, during 2020 and using a previously validated questionnaire. The answers were confronted to the result of our same study among 355 non-medical Moroccan young people (group 2) in 2019. Statistical analyses were performed using Statistical Package for the Social Sciences (version 10). Result: Medical students had a significantly higher level of knowledge about infertility than non-medical young people. However, both groups were aware of the impact of lifestyle on infertility. The knowledge state of the first group about infertility management was higher than the second group. Moreover, all non-medical Moroccan young people believed that it is easier to conceive if the couples had already their first baby, whereas, among medical students, only 53% had confirmed this belief. The results showed that 65% of medical students had proposed to try fertility treatments more than one time if treatment fails. Besides, the first advice of the second group was polygamy and adoption. Conclusion: Following the result of our study, the investigation of young people is the measure to optimize reproductive health. So, it’s crucial that the government increase efforts to improve the knowledge about infertility not only for medical universities but for all scholar programs.

Keywords: attitude, infertility, knowledge, medical, non-medical, young people

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Authors: Insaf Sayar, Moôtez Marzougui, Abderraouf Ben Abderrahman

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Background: Physical Education and Sports (PES) plays an important role in the overall education of the student. It has physical, affective, psychological, and social repercussions. In fact, overweight children are sometimes underestimated by their lower physical performance and suffer from discriminatory attitudes by their peers and their physical education (PE) teachers. Objectives: The aim of this study was to investigate the impacts of both teacher’s pedagogy and overweight or obesity on the inclusion of obese students in physical education classes in the school setting in the Emirate of Ajman (United Arab Emirates) and to understand how physical education and sports (PES) teachers adapt their pedagogical interventions towards this category. Methods: A sample of 48 overweight or obese students and 20 teachers were approached from different schools in Ajman Emirate. Two standardized questionnaires for obese students and PSE teachers were used. Overweight and obesity were defined using age and sex-specific Body Mass Index (BMI). Results: Our results showed that the average BMI of the surveyed students is 28.58 ± 3.14 kg/m². According to the collected data, 85.42% of obese students report that they do not practice physical activity or rarely practice outside of school, and 73.42% go to school by bus or car. In addition, 66.7% of the surveyed students said that being overweight is a barrier to PES practice, and 100% of obese or overweight students do not prefer some physical activities such as running and jumping. Similarly, 75% of the surveyed teachers said that obese students are not integrated into the PES course, but only 55% of teachers reported that the obese student became an obstacle in PES sessions, while 80% of teachers reported that obese or overweight students were marginalized by their colleagues. In the same way, most of them (75%) said that obese students are exempted from PES courses. Conclusion: Overweight/obesity is prevalent among school children in the Emirate of Ajman, with a high correlation with sedentary behavior. The study confirmed an urgent need and effective teaching strategies/ pedagogies for including overweight or obese students in physical education engagement and learning.

Keywords: adolescent, mainstreaming, obesity, PES education, UAE

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Authors: Wafa Toumi, Alessandro Ripalti, Luigi Ricciardiello, Dalila Gargouri, Jamel Kharrat, Abderraouf Cherif, Ahmed Bouhafa, Slim Jarboui, Mohamed Zili, Ridha Khelifa

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Background & aims: Colorectal cancer (CRC) is one of the most common malignancies throughout the world. Several risk factors, both genetic and environmental, including viral infections, have been linked to colorectal carcinogenesis. A few studies report the detection of human polyomavirus JC (JCV) DNA and transformation antigen (T-Ag) in a fraction of the colorectal tumors studied and suggest an association of this virus with CRC. In order to investigate whether such an association of JCV with CRC will hold in a different epidemiological setting, we looked for the presence of JCV DNA and T-Ag expression in a group of Tunisian CRC patients. Methods: Fresh colorectal mucosa biopsies were obtained from 17 healthy volunteers and from both colorectal tumors and adjacent normal tissues of 47 CRC patients. DNA was extracted from fresh biopsies or from formalin-fixed, paraffin-embedded tissue sections using the Invitrogen Purelink Genomic DNA mini Kit. A simple PCR and a nested PCR were used to amplify a region of the T-Ag gene. The obtained PCR products revealed a 154 bp and a 98 bp bands, respectively. Specificity was confirmed by sequencing of the PCR products. T-Ag expression was determined by immunohistochemical staining using a mouse monoclonal antibody (clone PAb416) directed against SV40 T-Ag that cross reacts with JCV T-Ag. Results: JCV DNA was found in 12 (25%) and 22 (46%) of the CRC tumors by simple PCR and by nested PCR, respectively. All paired adjacent normal mucosa biopsies were negative for viral DNA. Sequencing of the DNA amplicons obtained confirmed the authenticity of T-Ag sequences. Immunohistochemical staining showed nuclear T-Ag expression in all 22 JCV DNA- positive samples and in 3 additional tumor samples which appeared DNA-negative by PCR. Conclusions: These results suggest an association of JCV with a subpopulation of Tunisian colorectal tumors.

Keywords: colorectal cancer, immunohistochemistry, Polyomavirus JC, PCR

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