Hichem Chaker

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OprF is a general outer membrane porin of Pseudomonas aeruginosa, a well-known human opportunistic pathogen associated with severe hospital-acquired sepsis and chronic lung infections of cystic fibrosis patients. A multiphenotypic approach, based on the comparative study of a wild-type strain of P. aeruginosa, its isogenic oprF mutant, and an(More)
Pseudomonas aeruginosa is responsible for persistent infections in cystic fibrosis patients, suggesting an ability to circumvent innate immune defenses. This bacterium uses the kynurenine pathway to catabolize tryptophan. Interestingly, many host cells also produce kynurenine, which is known to control immune system homeostasis. We showed that most strains(More)
The Pseudomonas aeruginosa type III secretion system (T3SS) is known to be a very important virulence factor in acute human infections, but it is less important in maintaining chronic infections in which T3SS genes are downregulated. In vitro, the activation of T3SS expression involves a positive activating loop that acts on the transcriptional regulator(More)
Recently, due to their effective ability to deliver antigen to antigen-presenting cells in vivo, type III secretion system-based attenuated bacterial vectors have increasingly attracted attention for their potential interest in cancer vaccine development. We have previously developed live attenuated Pseudomonas aeruginosa type III secretion system-based(More)
In this paper, a technique based on hybrid particle swarm optimiser with breeding and subpopulation is presented for optimal design of reconfigurable dual-beam linear array antennas and planar arrays. In the amplitudephase synthesis, the design of a reconfigurable dual-pattern antenna array is based on finding a common amplitude distribution that can(More)
Modern systems of Wireless Communications have limited capacity and processing techniques are required more sophisticated in order to improve system performance. One of the techniques in vogue is the application of MIMO (Multiple Input Multiple Output), known to improve the channel capacity and or the probability of bit error. The purpose of this paper is(More)
In this paper a new effective optimization algorithm called hybrid particle swarm optimizer with breeding and subpopulation is presented. This algorithm is essentially, as PSO and GA, a population-based heuristic search technique, now in use for the optimization of electromagnetic structures, modeled on the concepts of natural selection and evolution (GA)(More)
A major problem in telecommunications is to adapt the information to be transmitted to the propagation channel. This, in order to obtain a good quality of wireless communications with high transmission rates , and the release cable users to allow them to move in large buildings. In this type of communication systems must be properly fight one effect of(More)
A computationally efficient global optimization method, the adaptive particle swarm optimization (APSO), is proposed for the synthesis of uniform and Gaussian amplitude arrays of two cases, i.e., the prior constraint in the synthesis of the element positions for both the cases is dmin = 0.5 λ, where dmin is the minimum distance between two adjacent(More)
In this paper, we intend to study the synthesis of the multibeam arrays. The synthesis implementation’s method for this type of arrays permits to approach the appropriated radiance’s diagram. An adaptive particle swarm optimization algorithm (APSO) is proposed to synthesis multibeam antenna arrays. The problem is formulated and solved by means of the(More)