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Vertical marginal gap &retention of ceramic full coverage &inlay retained ceramic fixed partial dentures

Open Journal of Stomatology 2011年第4期1卷 140-149页

作者： cherif mohsen 不详

Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were construc- ted and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-pro- ximal inlay + proximal box), tub-shaped (occluso-pro- ximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shap- ed inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was signifi-cant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant dif-ference than the other two inlay retained FPDs de-signs. Conclusions: There was no significant differ- ence between full coverage FPDs, tub-shaped & pro- ximal box shaped inlay retained FPDs as regard ver- tical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrep- ancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical mar- ginal discrepancies were in the range of clinical ac- ceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs de- signs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay re- tained FPDs designs. There was no difference as re- gard retentive strengths between tub-shaped & pro- ximal box shaped inlay retained FPDs.

关键词： Inlay Retained FPDs Full Coverage FPDs Retentive Strengths Vertical Marginal Discrepancies

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Corrosion effect on the flexural strength &micro-hardness of ips e-max ceramics

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Open Journal of Stomatology 2011年第2期1卷 29-35页

作者： cherif mohsen 不详

Objectives: The effect of ceramics construction (press- able, machinable) and corrosion on flexural strength and micro-hardness was studied. Materials & Methods: Two types of ceramics were tested: IPS e-max Press and IPS e-max CAD. Forty samples were constructed and divided into 2 groups according to the type of ceramics. Each group was then subdivided into 2 subgroups. Subgroups 1 were not subjected to corrosion while subgroups 2 were subjected to corro-sion test. Finally each subgroup was divided into 2 classes according to the type of test: biaxial flexural strength, micro-hardness. Results: There was a sig-nificant difference between the two tested ceramics as regard weight loss as IPS e-max CAD recorded less weight loss than IPS e-max Press. As regard the flex-ural strength, IPS e-max CAD recorded significant higher strength than IPS e-max Press. Corroded sam- ples recorded significant lower flexural strength than non-corroded samples for the two tested ceramics. As regard the Vickers micro-hardness test, the results showed significant difference between the two tested ceramics. IPS e-max CAD recorded higher mi-cro-hardness values than IPS e-max Press. The results also showed that the corroded samples recorded no significant micro-hardness values than non- corroded samples for the two tested ceramics. Conclusions: IPS e-max CAD recorded less weight loss weight loss after being subjected to corrosion test than IPS e-max Press. The method of fabrication affected the flexural strength µ-hardness of ceramic as machinable ceramic (e-max CAD) recorded significant higher data than pressable ceramic (e-mas Press). Corrosion decreased the flexural strength of both tested ceramics but had no effect on micro- hardness.

关键词： IPS E-Max Corrosion Flexural Strength Micro-Hardness

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New results for a Lasota-Wazewska model

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International Journal of Biomathematics 2019年第2期12卷 143-162页

作者： Farouk cherif mohsen Miraoui MaPSFA LR11ES35ISSATUniversity of Sousse4002 SousseTunisia IPEIK University of Kairouan3100 KairouanTunisia LR11ES53Faculty of Sciences of Sfax University of SfaxTunisia

In nature there is no phenomenon that is purely periodic,and this gives the idea to consider the measure pseudo almost periodic *** this paper,by employing a suitable fixed point theorem,the proper ties of the measure pseudo almost periodic functions and differential inequality,we investigate the existence and uniqueness of the measure pseudo almost periodic solutions for some models of Lasota-Wazewska equation with measure pseudo almost periodic coefficients and mixed *** suppose that the linear part has almost periodic and the nonlinear part is assumed to be measure pseudo almost ***,the global attractivity and the exponential stability of the measure pseudo almost periodic solutions are also considered for the *** application,an illustrative numerical example is given to demonstrate the effectiveness of the obtained results.

关键词： Lasota Wazewska model measure pseudo almost periodic function fixed point theorem

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Numerical Investigation of the Influence of a Magnetic Field on the Laminar Flow of a Yield-Stress Nanofluid over a Backward Facing Step

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Frontiers in Heat and Mass Transfer 2025年第1期23卷 185-206页

作者： Karim Amrani Eugenia Rossi di Schio Mohamed Bouzit Abderrahim Mokhefi Abdelkader Aris cherif Belhout Paolo Valdiserri Mechanical Manufacturing Technology Research Laboratory (LaRTFM) National Polytechnic School of Oran Maurice Audin El mnaouar Bp 1523 Es-senia Oran 31000 Algeria Department of Industrial Engineering DIN Alma Mater Studiorum-University of Bologna Viale Risorgimento 2 Bologna 40136 Italy Laboratory of Maritime Sciences and Engineering LSIM Faculty of Mechanical Engineering University of Science and Technology of Oran Mohamed Boudiaf El Mnaouer Oran 31000 Algeria Mechanics Modeling and Experimentation Laboratory L2ME Faculty of Sciences and Technology Bechar University Bechar 08000 Algeria

The present study focuses on the flow of a yield-stress (Bingham) nanofluid, consisting of suspended Fe 3 O 4 nanoparticles, subjected to a magnetic field in a backward-facing step duct (BFS) configuration. The duct is equipped with a cylindrical obstacle, where the lower wall is kept at a constant temperature. The yield-stress nanofluid enters this duct at a cold temperature with fully developed velocity. The aim of the present investigation is to explore the influence of flow velocity (Re = 10 to 200), nanoparticle concentration ( φ = 0 to 0.1), magnetic field intensity (Ha = 0 to 100), and its inclination angle (γ = 0 to 90) and nanofluid yield stress (Bn = 0 to 20) on the thermal and hydrodynamic efficiency inside the backward-facing step. The numerical results have been obtained by resolving the momentum and energy balance equations using the Galerkin finite element method. The obtained results have indicated that an increase in Reynolds number and nanoparticle volume fraction enhances heat transfer. In contrast, a significant reduction is observed with an increase in Hartmann and Bingham numbers, resulting in quasi-immobilization of the fluid under the magnetic influence and radical solidification of this type of fluid, accompanied by the suppression of the vortex zone downstream of the cylindrical obstacle. This study sheds light on the complexity of this magnetically influenced fluid, with potential implications in various engineering and materials science fields.

关键词： Yield-stress nanofluid Bingham nanofluid backward-facing step BFS magnetic field heat transfer hydrodynamics

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Cervical Compressive Myeloradiculopathy in Neurosurgery Consultation at Kipe Sino-Guinea Friendship Hospital: Epidemiological, Diagnostic and Therapeutic Aspects

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Open Journal of Modern Neurosurgery 2025年第1期15卷 48-55页

作者： Ibrahima Sory Souaré Jnr Mohamed cherif D. T. Boubane Seylan Diawara Ibrahima Sory Souaré Department of Neurosurgery Sino Guinean Friendship Hospital Conakry Guinea Department of Neurosurgery Hpital National Donka Conakry Guinea

Objective: To describe the epidemiological, clinical and therapeutic aspects of cervical compressive myeloradiculopathy seen in neurosurgery consultation at the Sino-Guinean Friendship Hospital (HASIGUI). Material and Methods: A prospective descriptive study was conducted at the Neurosurgery Department of the Sino-Guinean Friendship Hospital (Guinea, Conakry) over a 6-month period between May and November 2021. All patients seen in consultation, in whom the diagnosis of cervical compressive myeloradiculopathy (CRM) was established, were included. A survey form was used to collect epidemiological, clinical and therapeutic characteristics. Results: The hospital prevalence of cervical compressive myeloradiculopathy was 13.33%, or 42 cases among 315 neurosurgical pathologies. Men predominated (n = 34;81%) with a mean age of 52.8 ± 11.4 years and extremes of 38 and 81 years;the professional categories of administrators and professionals were affected in the same proportion (15 cases, or 35.7% of cases);chronic neck pain was found in 38 patients (88.4%) as a previous history. The most common reasons for consultation were: neck pain (100% of cases), paresthesia of the fingertips (92.9% of cases), cervicobrachial neuralgia (78.6% of cases), weakness of the upper limbs (64.3% of cases), cramps (61.9%), sphincter disorders (38.1% of cases). The most common cause found on the basis of neuroimaging was cervicarthrosis in 40.3% of the cases, with an improvement of medical treatment in 59.5% and surgical decompression in 19% of the cases. Conclusion: Cervical compressive myeloradiculopathy is increasingly diagnosed in our working environment. It is the prerogative of the elderly subject, who has male predominance. Neurological signs are in the foreground. CT and/or MRI is the imaging test of choice for diagnosis.

关键词： MRCC Neurochirurgie HASIGUI

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Imaging of target with complicated motion using ISAR system based on IPHAF-TVA

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Chinese Journal of Aeronautics 2021年第2期34卷 252-264页

作者： Abdelkader ALI cherif Yong WANG Algerian Space Agency Satellite Development CenterOran 31000Algeria Research Institute of Electronic Engineering Technology Harbin Institute of TechnologyHarbin 150001China

The technique of imaging a target with a complicated motion using an Inverse Synthetic Aperture Radar(ISAR) system is an effective tool in the field of radar signal processing. After the translational compensation, the received signal reflected from the target can take the form of a multi-component Polynomial Phase Signal(m-PPS), and the high quality ISAR image can be provided via the combination between the estimated parameters of the m-PPS and the Range Instantaneous-Doppler technique(RID). For a target with a high maneuvrability, the occurrence of scatterers Migration Through Resolution Cell(MTRC), caused by the rotational movement could be appearing. That is why the variation in the amplitude of the echo during the time of observation cannot be neglected. The purpose of this study is the parameters estimation of the m-PPS signal with order three in the case of the Time Varying Amplitude(TVA). The Improved-version of the Product High-order Ambiguity Function(IPHAF) with TVA is proposed to improve the quality of the ISAR image compared with traditional techniques based on a constant amplitude;the experimental outcomes confirm that the new IPHAF-TVA method presented in this study is an effective technique to make the ISAR image very clear.

关键词： Inverse Synthetic Aperture Radar(ISAR) Maneuvering target Multi-component Polynomial Phase Signal(m-PPS) Product High-Order Ambiguity Function(IPHAF) Time Varying Amplitude(TVA)

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Thermal performance of lightweight concrete applications in building envelopes in Lebanon

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Building Simulation 2021年第5期14卷 1359-1375页

作者： Emilio Sassine Elias Kinab Yassine cherif Emmanuel Antczak Michel Nasrallah Lebanese University Habitat and Energy UnitGroup of Thermal and Renewable Energies-Laboratory of Applied Physics(LPA-GMTER)Faculty of SciencesFanar CampusLebanon Lebanese University Faculty of EngineeringRoumiehEl MetnLebanon Univ.Artois ULR4515Laboratoire de Genie Civil et geo-Environnement(LGCgE)BethuneF-62400France CC Technique Memari StreetHamraBeirutLebanon

Innovative building materials are being used in building envelopes for reducing their heating and cooling *** paper aims to assess the thermal impact of using lightweight concrete in Lebanese building constructions by pouring an 8 cm thickness of lightweight concrete on the roof and the slab and replacing traditional hollow concrete block by lightweight concrete *** properties of two different samples were experimentally determined:the first one(558 kg/m^(3))used for the roof and the slab and the second one(1074 kg/m^(3))used for the *** numerical simulations were carried out for a Lebanese traditional detached house using the characteristics of these two *** thermally improved Light Weight Concrete building(LWC)was compared to a traditional Lebanese house base case(BC)using a dynamic building energy simulation tool in the four different Lebanese climate zones:coastal,mid-mountain,mountain,and inland *** results highlight the effectiveness of integrating LWC to building envelopes by reducing energy consumption and improving thermal comfort in both winter and summer climate conditions and in the different Lebanese climatic *** paper demonstrates that the use of LWC in the vertical walls replacing the traditional hollow blocks can reduce the heating needs by up to 9%and by up to 13%for cooling *** the other hand,adding a LWC roof screed has a very high impact on cooling and heating energy consumption,which can reach up to 74%in cooling energy savings and up to 24%in heating energy savings.

关键词： lightweight concrete thermal properties building energy simulation thermal insulation climatic conditions

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Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants (Solanum lycopersicum)

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Journal of Environmental Sciences 2011年第5期23卷 837-844页

作者： Jaouhra cherif Chamseddine Mediouni Wided Ben Ammar Fatma Jemal Unit of Research "Nitrogenized Nutrition and Metabolism and Stress Proteins" UR 99/09-20 Department of BiologyFaculty of Science University of Tunis Tunis 2092 Tunisia Unit of Research "Nitrogenized Nutrition and Metabolism and Stress Proteins" UR 99/09-20 Department of BiologyFaculty of ScienceUniversity of Tunis Tunis 2092 Tunisia

The interaction between zinc and cadmium was investigated in tomato plants （Solanum lycopersicum）. Ten-day-old seedlings were treated with 10 μmol/L CdC12 associated to different concentrations of ZnC12 （10, 50, 100, and 150 μmol/L）. Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances （TBARS） level and chlorophyll breakdown. Furthermore, compared with control, Cd- treated plants had significantly higher activities of superoxide dismutase （SOD, EC 1.***.1.1）, whereas, catalase （CAT, EC 1.***.1.6）, ascorbate peroxidase （APX, EC 1.***.1.11）, and glutathione reductase （GR, EC 1.***.4.2） activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes （SOD, CAT, APX and GR） as compared to Cd-alone-treated plants. The beneficial effect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their effect on plant growth parameters and oxidative stress.

关键词： Solanum lycopersicum cadmium zinc oxidative stress antagonism synergism.

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Extracts from Marine Macroalgae and Opuntia ficus-indica Cladodes Enhance Halotolerance and Enzymatic Potential of Diazotrophic Rhizobacteria and Their Impact on Wheat Germination Under Salt Stress

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Pedosphere 2018年第2期28卷 241-254页

作者： Abdelwahab RAI Ameur cherif Cristina CRUZ Elhafid NABTI Département de Microbiologie Faculté des Sciences de la Nature et de la Vie Université Ferhat Abbas Sdtif-1 19000 (Algdrie) Universitg de Béjaia FSNV Laboratoire de Maitrise des Energies Renouvelables (LMER) Equipe de Biomasse et Environnement Targa Ouzemmour Béaia 06000 (Algérie) LR Biotechnology and Bio-Geo Resources Valorization Higher Institute for Biotechnology University of Manouba Sidi Thabet Biotechpole 2020 Sidi Thabet Ariana 2080 (Tunisia) cE3c-Centre for Ecology Evolution and Environmental Changes Campo Grande Bloco C-2 Piso 5 Sala 03 Lisboa 1749-016 CPor- tugal)

Soil salinity, which affects more than 6% of the earth’s land surface and more than 20% of its irrigated areas, is a major threat to agriculture. Diazotrophic bacteria are among the functional groups of soil microbiota that are threatened by this abiotic stress, as their activity is mostly inhibited by salt stress. Seventy bacterial strains with distinct characteristics were isolated from soils by using N-free Jensen’s selective medium. Based on their ability to produce metabolites of agricultural interest, four strains were selected and identified as Flavobacterium johnsoniae, Pseudomonas putida, Achromobacter xylosoxidans, and Azotobacter chroococcum. The selected strains were grown at different NaCl concentrations (0–600 mmol L^(-1) in N-free broth and 0–2 000 mmol L^(-1) in Luria-Bertani medium) in the presence and absence of glycine betaine (GB), aqueous and hydro-alcoholic extracts from marine macroalgae, Ulva lactuca and Enteromorpha intestinalis, and Opuntia ficus-indica cladodes. The selected bacterial strains, GB, and the aforementioned extracts were tested for their ability to promote the germination of wheat (Triticum durum) seeds at 0–300 mmol L^(-1) NaCl. Compared with the results obtained with the synthetic osmoprotectant GB, the extracts from O. ficus-indica, U. lactuca, and E. intestinalis significantly promoted bacterial growth and seed germination under salt stress.

关键词： glycine betaine Ulva lactuca Enteromorpha intestinalis plant growth-promoting rhizobacteria (PGPR) seed germi-nation Triticum durum

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DYNAMICS OF NEW CLASS OF HOPFIELD NEURAL NETWORKS WITH TIME-VARYING AND DISTRIBUTED DELAYS

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Acta Mathematica Scientia 2016年第3期36卷 891-912页

作者： Adnene ARBI Farouk cherif Chaouki AOUITI Abderrahmen TOUATI Department of Mathematics Facultd des Sciences de BizerteUniversity of CarthageJarzouna 7021BizerteTunisia Department of Computer Science ISSATSLaboratory of Math PhysicsUniversity of SousseSpecials Functions and Applications LR11ES35ecole suprieure des sciences et de technologieSousse 4002Tunisia

In this paper, we investigate the dynamics and the global exponential stability of a new class of Hopfield neural network with time-varying and distributed delays. In fact, the properties of norms and the contraction principle are adjusted to ensure the existence as well as the uniqueness of the pseudo almost periodic solution, which is also its derivative pseudo almost periodic. This results are without resorting to the theory of exponential dichotomy. Furthermore, by employing the suitable Lyapunov function, some delayindependent sufficient conditions are derived for exponential convergence. The main originality lies in the fact that spaces considered in this paper generalize the notion of periodicity and almost periodicity. Lastly, two examples are given to demonstrate the validity of the proposed theoretical results.

关键词： delayed functional differential equations neural networks pseudo-almost peri- odic solution global exponential stability time-varying and distributed delays fixed point theorem

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