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Marrakesh, Morocco

Ahboucha S.,Cadi Ayyad University
Current Molecular Pharmacology | Year: 2011

Cerebral complications of liver failure either due to chronic or acute manifestations lead to a neurological disorder known as Hepatic encephalopathy (HE). Neurosteroids, synthesized in the brain mainly by astrocytes but also in other brain cells independently from peripheral steroidal sources such as adrenal and gonads, are suggested to play a role in the pathogenesis of HE. The mechanisms by which neurosteroids affect brain function are not totally elucidated but may involve both genomic and non genomic effects. On the one hand, neurosteroids bind and modulate different types of neuronal memebrane receptors. While neurosteroids may affect directly postsynaptic receptors including GABAA, 5-HT3, NMDA, glycine, and opioid receptors which have been involved in HE, neurosteroids effects through GABAA receptors may also compromise indirectly the function of neurons networking with GABAergic interneurons. On the other hand, some neurosteroids bind to intracellular receptors through which they also regulate gene expression, and there is substantial evidence confirming that expression of genes coding for key astrocytic and neuronal proteins is altered in HE. The mechanisms that trigger brain neurosteroid changes in HE are not yet established, but could involve (i) ammonia and manganese (in chronic HE)-induced translocator protein (TSPO) activation, (ii) neuroinflammation or (iii) blood-brain transfer of lipophylic neuroactive steroids. The present review summarizes evidence for the involvement of neurosteroids in HE and possible mechanisms for their altered brain production and central effects in human and experimental HE. © 2011 Bentham Science Publishers Ltd. Source

Benzaouia A.,Cadi Ayyad University | El Hajjaji A.,University of Picardie Jules Verne
International Journal of Innovative Computing, Information and Control | Year: 2011

This paper deals with the problem of delay-dependent stability and the stabilization of Takagi-Sugeno (T-S) fuzzy systems with a time-varying delay while imposing positivity in closed-loop. The stabilization conditions are derived using the single Lyapunov-Krasovskii Functional (LKF) combining the introduction of free-single matrices. A memory feedback control is also used in case the delay matrix is not nonnegative. An example ofa real plant is studied to show the advantages of the design procedures. ICIC International © 2011. Source

Benbrik R.,Cadi Ayyad University | Chen C.-H.,National Cheng Kung University | Nomura T.,Korea Institute for Advanced Study
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

ATLAS and CMS recently showed the first results from run 2 of the Large Hadron Collider (LHC) at s=13 TeV. A resonant bump at a mass of around 750 GeV in the diphoton invariant mass spectrum was indicated and the corresponding diphoton production cross section is around 3-10 fb. Motivated by the LHC diphoton excess, we propose that the possible resonance candidate is a Higgs singlet. To produce the Higgs singlet via the gluon-gluon fusion process, we embed the Higgs singlet in the framework of the vector-like triplet quark (VLTQ) model. As a result, the Higgs singlet decaying to the diphoton final state is via VLTQ loops. Using the enhanced number of new quarks and new Yukawa couplings of the VLTQs and Higgs singlet, we successfully explain the diphoton production cross section. We find that the width of the Higgs singlet is below 1 GeV, its production cross section can be of the order of 1 pb at s=13 TeV, and the branching ratio for it decaying to a diphoton is around 0.017 and is insensitive to the masses of VLTQs and new Yukawa couplings. We find a strong correlation between the Higgs Yukawa couplings to s-b and c-t; the resulted branching ratio for t→ch can be 1.1×10-4 when the constraint from Bs oscillation is applied. With the constrained parameter values, the signal strength for the standard model Higgs decaying to a diphoton is μγγ<1.18, which is consistent with the current measurements at ATLAS and CMS. © 2016 American Physical Society. Source

El Modafar C.,Cadi Ayyad University
Physiological and Molecular Plant Pathology | Year: 2010

The Bayoud disease, caused by Fusarium oxysporum f. sp. albedinis (Foa), represents a major limiting factor of date palm culture in Morocco and constitutes a serious threat to the date palm plantations in Algeria and all other countries. Efficient disease prevention requires the development of resistant cultivars. In Morocco, among the cultivars listed, only six appear to be resistant to Bayoud disease, but they produce poor quality fruit. Thus, the Moroccan program of date palm genetic improvement is based on directed crossing between resistant cultivars and susceptible cultivars with good date quality traits to select resistant genotypes producing high quality fruits. In addition to the separation of the resistance to Bayoud disease and quality of the fruits characters, this breeding program is really complex due to the sex separation in the date palm, the duration of juvenile phase which is very long, and the lifespan of the date palm which requires a durable polygenic resistance. Then, the selected genotypes must be of female sex, of good date quality, and possess effective defense mechanisms against the pathogen. Moreover, the selection of the date palm resistance must necessarily take into account the mechanisms of pathogen aggressiveness. In this review, we will present and discuss studies developed on the Bayoud disease of the date palm, particularly on the disease control, the biochemical and molecular markers of resistance, the program of date palm genetic improvement of resistance, the Foa pathogenicity factors, and host defense mechanisms. It will also highlight the recent studies that showed that differential behaviour of the resistant and susceptible cultivars was not related to a difference of induction of the defense mechanisms, but to the suppression of their elicitation in the susceptible cultivars. © 2010 Elsevier Ltd. Source

Bellouquid A.,Cadi Ayyad University | De Angelis E.,Polytechnic University of Turin
Nonlinear Analysis: Real World Applications | Year: 2011

This paper deals with the derivation of macroscopic equations of biological tissues for a class of nonlinear equations, with quadratic type nonlinearity, modeling complex multicellular systems. Cellular interactions generate both modification of biological functions and proliferative/destructive events. The asymptotic analysis refers to the derivation of hyperbolic models focused on the influence of existence of a global equilibrium solution. The asymptotic analysis shows how the macroscopic tissue behavior can be described from the underlying cellular description and that this specific biological state modifies the structure of the models obtained by different assumptions. The approach is proposed as an alternative to the phenomenological of continuum mechanics for growing tissues. © 2010 Elsevier Ltd. All rights reserved. Source

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