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OALib Journal期刊

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Evaluation of Cardiovascular Risk Factors in Tunisian Coronary Patients  [PDF]
Grira Nadra, Sandesni Rihab, Lamine Ossama, Aboulkassem Sana, Ayoub Manel, El Oudi Mabrouka, Stambouli Najla, Lahidheb Thaker, Haouala Habib, Mazigh Chakib, Aouni Zied
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104214
Abstract:
Introduction: Ischemic heart disease ranked among the leading causes of death worldwide. Several biological and genetic risk factors associated with acute coronary syndrome. By addressing the risk factors, it is possible to prevent most of the cardiovascular diseases and contribute to the reduction of complications of acute coronary syndrome. Material and Methods: Our study is a prospective study that was conducted to the main military hospital of instruction of Tunis. Recruitment involved 122 coronary (n = 122) and 705 controls (n = 705) totaling a population of 827 subjects. Data collection concerned socio-demographic characteristics, anthropometric measurements, habits and lifestyle, health status and biological assessment. Results: Our study reported a high prevalence of cardiovascular classic risk factor particularly overweight (62.3%), diabetes (63.1%) and hypertension (50%). In 55% of coronary patients, moderate to intermediate hyperhomocysteinemia was found, but it appears to be an independent risk factor. The results of our study show a significant difference in the genotypic frequencies of the C677T mutation in the MTHFR gene between the two populations, cases and controls. Conclusion: Acute coronary syndromes are the leading cause of sudden death in adults. The evaluation of risk factors after acute coronary syndrome episode is essential for a better management according to the recommendations of learned societies and standards of good practice.
A SINGLE PHOTON SOURCE MODEL BASED ON QUANTUM DOT AND MICROCAVITY
Moez ATTIA,Rihab CHATTA
International Journal of Distributed and Parallel Systems , 2011,
Abstract: We report a single photon source model which consists on InAs/GaAs pyramidal quantum dot (QD)model based on effective mass theory to calculate the emitted photons energies. We study the choice ofgeometrics parameters of QD to obtain emission at 1550 nm. This quantum dot must be embedded on amicrocavity to improve the live time of photon at 1550 nm and inhibit the others photons to increase theprobability to obtain only one emitted photon. We present two kinds of microcavities; the first based ontwo dimensional photonic crystal over GaAs, we study the geometric parameters choice to obtain a heightdensity of mode (DOM) at 1550 nm; the second microcavity is based on microdisk structure over GaAswe evaluate the impact of radius variation to obtain whispering-gallery mode at 1550 nm. This study canserve for the conception of new quantum communications protocols.
ELabMate: A Tool for Delivering Programming Courses Effectively
Rihab Eltayeb Ahmed
International Journal of Advanced Corporate Learning (iJAC) , 2012, DOI: 10.3991/ijac.v5i3.2189
Abstract: In the Sudan, at the university level, mastering one of the current programming languages is typically required in order for a student to graduate from computer science majors. In Sudan University of Science and Technology (SUST), Traditional teaching methods of introductory programming courses involve lectures and practical sessions where students and teachers meet and discuss. Other resources are devoted to the courses including free lab sessions and tutorials with supporting staff and teaching assistants. Learning management systems and page-turning courses are available, complemented by a mass of online information, little of which is structured or written to help students learn successfully. To help students in the learning process, more training and practice on lab problems with a guided help is needed in addition to the normal sessions. As a result finding the middle ground between student’s needs and the limited staff and time schedules is challenging. In this context we propose the development of an e-learning tool (ELabMate) to provide assistance to students and teachers. The two main potential users of the tool would be students and teachers with a dedicated interface for each, other administrative users can be found with respect to the academic rules drawing attention to the active role of every part involved in the learning process. The goal is to help students learn programming concepts based on assisting and engaging them in their learning process in a way that improves their performance. The tool real innovation is not being a text editor, but the ability to monitor students while writing their code and to provide hints the way the instructors do.
Maximum Power Point Tracking Control Using Neural Networks for Stand-Alone Photovoltaic Systems  [PDF]
Rihab Mahjoub Essefi, Mansour Souissi, Hsan Hadj Abdallah
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.33008
Abstract:

The employment of maximum power point tracking techniques in the photovoltaic power systems is well known and even of immense importance. There are various techniques to track the maximum power point reported in several literatures. In such context, there is an increasing interest in developing a more appropriate and effective maximum power point tracking control methodology to ensure that the photovoltaic arrays guarantee as much of their available output power as possible to the load for any temperature and solar radiation levels. In this paper, theoretical details of the work, carried out to develop and implement a maximum power point tracking controller using neural networks for a stand-alone photovoltaic system, are presented. Attention has been also paid to the command of the power converter to achieve maximum power point tracking. Simulations results, using Matlab/Simulink software, presented for this approach under rapid variation of insolation and temperature conditions, confirm the effectiveness of the proposed method both in terms of efficiency and fast response time. Negligible oscillations around the maximum power point and easy implementation are the main advantages of the proposed maximum power point tracking (MPPT) control method.

Essential oil of Thymus vulgaris L. and Rosmarinus officinalis L.: Gas chromatography-mass spectrometry analysis, cytotoxicity and antioxidant properties and antibacterial activities against foodborne pathogens  [PDF]
Hanene Miladi, Rihab Ben Slama, Donia Mili, Sami Zouari, Amina Bakhrouf, Emna Ammar
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.56090
Abstract:

The essential oil composition of Thymus vulgaris L. and Rosmarinus officinalis L. endemic to France were determined by GC and GC-MS. Oils were assessed for their cytotoxic, antioxidant and antimicrobial activity. 31 and 37 different compounds were identified representing 99.64% and 99.38% of the thyme and rosemary oils respectively, where oxygenated monoterpenes constituted the main chemical class. Thymol (41.33%) and 1.8-cineole (24.10%) were identified as the main constituents of T. vulgaris L. and R. officinalis L., respectively. Essential oils (EOs) of selected plant species were evaluated for their in vitro cytotoxicity against the human lung adenocarcinoma epithelial cell line (A549). Cytotoxicity was measured using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphynyltetra-zolium bromide] colorimetric assay. Dose-dependent studies revealed IC50 of 8.50 ± 0.01 μg/mL and 10.50 ± 0.01 μg/mL after 72 h on the A549 cells for R. officinalis L. and T. vulgaris L., respectively. Antioxidant activity was determined using a quantitative DPPH (1,1-diphenyl- 2-picryl hydrazyl) assay. Thymus and rosemary EOs exhibited effective radical scavenging capacity with 50% inhibitory concentration (IC50) of 437 ± 5.46 μg/mL and 189 ± 2.38 μg/mL respectively and therefore acts as a natural antioxidant agent. The antimicrobial activity of these species has also been studied against several foodborne pathogens and food isolated Salmonella spp. including S. enteritidis of significant importance. According to the results, T. vulgaris L. showed higher bactericidal effect than those from R. officinalis L. These results suggest that the essential oil from T. vulgaris L. and R. officinalis L. have potential to be used as a natural cytotoxic, antioxidant and antimicrobial agent in food processing.

Dissipative systems: uncontrollability, observability and RLC realizability
Selvaraj Karikalan,Madhu N. Belur,Rihab Abdulrazak
Mathematics , 2011,
Abstract: The theory of dissipativity has been primarily developed for controllable systems/behaviors. For various reasons, in the context of uncontrollable systems/behaviors, a more appropriate definition of dissipativity is in terms of the dissipation inequality, namely the {\em existence} of a storage function. A storage function is a function such that along every system trajectory, the rate of increase of the storage function is at most the power supplied. While the power supplied is always expressed in terms of only the external variables, whether or not the storage function should be allowed to depend on unobservable/hidden variables also has various consequences on the notion of dissipativity: this paper thoroughly investigates the key aspects of both cases, and also proposes another intuitive definition of dissipativity. We first assume that the storage function can be expressed in terms of the external variables and their derivatives only and prove our first main result that, assuming the uncontrollable poles are unmixed, i.e. no pair of uncontrollable poles add to zero, and assuming a strictness of dissipativity at the infinity frequency, the dissipativities of a system and its controllable part are equivalent. We also show that the storage function in this case is a static state function. We then investigate the utility of unobservable/hidden variables in the definition of storage function: we prove that lossless autonomous behaviors require storage function to be unobservable from external variables. We next propose another intuitive definition: a behavior is called dissipative if it can be embedded in a controllable dissipative {\em super-behavior}. We show that this definition imposes a constraint on the number of inputs and thus explains unintuitive examples from the literature in the context of lossless/orthogonal behaviors.
Energy-Aware Forwarding Strategy for Metro Ethernet Networks
Rihab Maaloul,Lamia Chaari Fourati,Bernard Cousin
Computer Science , 2015,
Abstract: Energy optimization has become a crucial issue in the realm of ICT. This paper addresses the problem of energy consumption in a Metro Ethernet network. Ethernet technology deployments have been increasing tremendously because of their simplicity and low cost. However, much research remains to be conducted to address energy efficiency in Ethernet networks. In this paper, we propose a novel Energy Aware Forwarding Strategy for Metro Ethernet networks based on a modification of the Internet Energy Aware Routing (EAR) algorithm. Our contribution identifies the set of links to turn off and maintain links with minimum energy impact on the active state. Our proposed algorithm could be a superior choice for use in networks with low saturation, as it involves a tradeoff between maintaining good network performance and minimizing the active links in the network. Performance evaluation shows that, at medium load traffic, energy savings of 60% can be achieved. At high loads, energy savings of 40% can be achieved without affecting the network performance.
Induction of epstein-barr virus (EBV) lytic cycle in vitro causes lipid peroxidation, protein oxidation and DNA damage in lymphoblastoid B cell lines
Bochra Gargouri, Rihab Nasr, Malek Mseddi, Riadh benmansour, saloua Lassoued
Lipids in Health and Disease , 2011, DOI: 10.1186/1476-511x-10-111
Abstract: After 48 h (peak of lytic cycle), a significant increase in conjugated dienes level was observed in B95-8 and Raji cell lines (p = 0.0001 and p = 0.019 respectively). Malondialdehyde adduct, protein carbonyl levels were increased in B95-8 and Raji cell lines after EBV lytic cycle induction as compared to controls (MDA-adduct: p = 0.008 and p = 0.006 respectively; Carbonyl: p = 0.003 and p = 0.0039 respectively). Proteins thiol levels were decreased by induction in B95-8 and Raji cell lines (p = 0.046; p = 0.002 respectively). DNA fragmentation was also detected in B95-8 and Raji cell lines after EBV lytic cycle induction as compared to controls.The results of this study demonstrate the presence of increased combined oxidative modifications in lipids, proteins in B95-8 and Raji cells lines after EBV lytic cycle induction. These results suggest that lipid peroxidation, protein oxidation and DNA fragmentation are generally induced during EBV lytic cycle induction and probably contribute to the cytopathic effect of EBV.Epstein Barr virus (EBV) is a ubiquitous gammaherpesvirus that infects more than 90% of the human population. The EBV can infect its target cells in both a latent and a lytic mode. The latent cycle is characterized by the expression of six Epstein-Barr nuclear antigens (EBNAs), three latent membrane proteins LMP1, LMP2A, and LMP2B, two untranslated RNAs (EBER), and a family of transcripts from the BMH1A region of the genome [1,2]. Upon EBV reactivation, two key immediate early (IE) lytic genes, BZLF1 and BRLF1, encoding Zta (BZLF1 transcription activator) and Rta (BRLF1 transcription activator) respectively, are transcribed, and consequently activate several downstream viral promoters and lead to an ordered cascade of viral gene expression [3]. The latent form of EBV can be induced to enter the lytic form in vitro by treatment with various chemicals, including 12- 0-tetradecanoylphorbol-13-acetate (TPA) [4], halogenated pyrimidine [5], n-butyrate [6], cal
Modelling and Control of an Optimized PV Array with Hydrogensystem Comprising a PEMFC and an Electrolyzer
Rihab Jallouli,Lotfi Krichen,Bruno Francois,Abderrazak Ouali
International Journal of Electrical and Power Engineering , 2012,
Abstract: This research deals with the modelling and the control of a hydrogen system comprising a Proton Exchange Membrane Fuel Cell (PEMFC) and an Electrolyzer (EL) to optimize the power use of a small photovoltaic source. The Photovoltaic panel (PV) provides energy to the load, the excess energy produced, with respect to the load requirements will be sent to the electrolyzer for hydrogen production and storage. Dynamic modelling of various components of this small system is presented. The performances of this source are demonstrated by digital simulation.
Redox-responsive probes for selective chelation of bivalent cations
Noureddine Raouafi,Janet Bahri,Rihab Sahli,Khaled Boujlel
QScience Connect , 2012, DOI: 10.5339/connect.2012.8
Abstract: N,N-disubstituted bis(furanyl-2-methyl)aminoanilines are new electrochemically-active probes for cations relying on the phenylenediamine moiety as an electroactive transducer and the difuranylamino group as an ionophore site. The electrochemical investigations, by means of cyclic and Osteryoung square wave voltammetries (CV and SWV, respectively), showed that these compounds are able to bind Mg2+, Ca2+, Ni2+ and Zn2+ cations with strong affinities. The addition of catalytic amounts of trifluoromethanesulfonic acid (TfOH) was found necessary to achieve rapid cation complexation. The electroactive redox features of the probes were drastically modified when the ionophore site was bonded to the cations. The anodic potential shifts of the oxidation peaks were between 905 and 1030 mV depending on the cations.
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