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19 result(s) for "Ben Yahia, Hamza"
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EP163/#1029 Expression of human leucocyte antigen G (HLA-G) is associated with deep myometrial invasion and worse survival in endometrial carcinoma
ObjectivesHuman leukocyte antigen G (HLA-G) is a non-classical class I molecule that regulates many immune functions. This molecule has been proposed to be involved in tumor escape mechanisms. We aimed to investigate immunohistochemical expression of HLA-G molecules in endometrial carcinoma (EC) and its association with myometrial invasion and overall survival rate.MethodsImmunohistochemical analysis using the 4H84 anti-HLA-G monoclonal antibody was performed on a total of 31 patients with EC. Tumor cells that exhibited granular cytoplasmic brown staining were considered to be positive. The association between HLA-G status and myometrial invasion was analyzed using Chi-square test. The survival analysis was evaluated by Kaplan-Meier method.ResultsImmunohistochemical analysis of EC revealed HLA-G protein immunoreactivity in 38.7% (12/31) of specimens. We identify 58% (18/13) of patients with more than 50% myometrial invasion. Statistically significant association was found between HLA-G expression and depth of myometrial invasion (p=0,02). Patients with HLA-G positive tumors had a shorter survival time than those patients with tumors that were HLA-G negative (mean survival = 48 and 84 months, respectively) with significance trend (log-rank p=0.09).ConclusionsOur preliminary data suggest that HLA-G expression in EC may be potentially predictive of extrauterine metastases which are more observed in patients with more than 50% myometrial invasion. Likewise, this expression should be considered as prognostic indicator. This parameter should be evaluated to ensure better management of these patients.
Pregnancy and breastfeeding: a new theory for sHLA-G in breast cancer patients?
It is now widely recognized that HLA-G molecule is implicated in immune tolerance and particularly in immune subversion of tumor cells. In this study, we explored levels of soluble HLA-G (sHLA-G) in plasma samples obtained from women with breast cancer (BC). Additionally, we correlated sHLA-G concentration with pregnancy and breastfeeding history. We reported in this preliminary work significant differences in sHLA-G levels between BC patients with/without breastfeeding experience ( p  = 0.04). Interestingly, among women with BC, only those without previous pregnancy experience present significant increase in sHLA-G ( p  = 0.02). Of relevance, we demonstrated that patients without both pregnancy and breastfeeding history have advanced SBR III grade, associated with significant enhancement in tumor size compared with patients who had both experiences ( p  = 0.028). Taken together, our results indicate the potential implication of previous pregnancy and breastfeeding experience in sHLA-G expression during BC. We theorized that having pregnancy and breastfeeding history may protect against advanced BC stages.
Human leukocyte antigen (HLA-F) polymorphism is associated with chronic HBV infection
Human leukocyte antigen (HLA)-F has been involved in immune regulation of infectious diseases. However, the role of HLA-F polymorphisms in hepatitis B infection outcomes remains unclear. Here, we aimed to determine HLA-F polymorphism implication in chronic HBV. Genotype analysis was performed for three single nucleotide polymorphisms (SNPs) of HLA-F and one SNP of HLA-E using PCR-SSP, in 252 Tunisian patients with chronic HBV infection stratified according to their HBV DNA levels (140 patients with low HBV DNA levels < 2000 IU/mL and 112 patients with high HBV DNA levels ≥ 2000 IU/mL) and 240 healthy controls (CTRL). The three HLA-F SNPs (HLA-F*01:02, -F*01:03 and -F*01:04) have the same allelic and genotypic frequencies in patients and in CTRL. We reported a low HLA-F*01:02 and F*01:04 allelic frequencies in the Tunisian population; however, high HLA-F*01:03 allele frequencies were observed (17%). A significant association was found between the HLA-F*01:03 allele and decreased level of HBV DNA (P = 0.02 OR 0.56, 95% CI 0.35–0.92). No significant differences were observed in haplotype distribution between patients and CTRL. A significant association of HLA-F*01:03 with the level of HBV DNA suggests an important role of HLA-F in HBV replication control.
Association of HLA-G 3′UTR polymorphisms with hepatitis B virus infection in Tunisian population
Hepatitis B virus (HBV) infection is a major public health burden. The mechanisms of immune evasion during chronic HBV (CHB) infection are poorly understood. Human leukocyte antigen (HLA)-G, an immune checkpoint molecule, plays a crucial role in the tolerance mechanisms of various infectious diseases. The 3′ untranslated region (3′UTR), including the HLA-G + 3142 C > G polymorphism (rs1063320) and the 14-pb Ins/Del (rs66554220) has been strongly suggested to influence HLA-G expression. This study conducted a case-control analysis to evaluate the potential correlation between the HLA-G + 3142 C > G polymorphism and HBV infection outcome in a Tunisian cohort. The HLA-G + 3142 C > G polymorphism was analysed by PCR-RFLP in 242 patients with chronic HBV infection (116 males and 126 females), 241 healthy controls (116 males and 125 females), and 100 spontaneously resolved subjects (52 males and 48 females). Patients with chronic HBV infection showed a higher frequency of the + 3142G allele compared to healthy controls and spontaneously resolved subjects (p = 0.001 and p = 0.002, respectively). An association between the + 3142G allele and high HBV DNA levels was observed when HBV patients were stratified based on their HBV DNA levels (p = 0.016). Furthermore, the dominant model (GG + GC vs CC) was associated with liver function parameters, including AST, ALT, and high HBV DNA levels (p = 0.04, p < 0.001 and p = 0.002, respectively). However, there was no significant association found between this polymorphism and the fibrosis stage (p = 0.32). The haplotype analysis, using a subset of previously published data on the HLA-G 14-pb Ins/Del polymorphism, revealed an association between the Ins/G haplotype and chronic HBV infection (H1: InsG, p < 0.001). Our findings suggest that the + 3142G allele is a risk factor for the persistence and progression of HBV infection, while the + 3142C allele serves as a protective allele associated with the spontaneous resolution of the infection. Additionally, the HLA-G 3′UTR haplotype Ins/G is associated with chronic HBV infection in the Tunisian population.
Experimental Study and Numerical Modelling of Low Velocity Impact on Laminated Composite Reinforced with Thin Film Made of Carbon Nanotubes
In this work, polymer laminated composites based on Epon 862 Epoxy resin, T300 6 k carbon fibers and carbon nanotubes (CNTs) were tested with the aim to elucidate the effect of CNTs on impact properties including impact force and capacity to absorb impact energy. The polymer matrix was reinforced by a random distribution of CNTs with fraction ranging from 0.5 to 4.wt%. Composite panels were manufactured by using the infusion process. Taylor impact test was used to obtain the impact response of specimens. Projectile manufactured from a high strength and hardened steel with a diameter of 20 mm and 1.5 kg of mass was launched by a compressed gas gun within the velocity of 3 m/s. Impact force histories and absorbed energy of specimens were recorded. A numerical model was employed to simulate the impact performance. This model has been accomplished by forming a user established subroutine (VUMAT) and executing it in ABAQUS software. Finally, the effect of CNTs amount on dynamic properties of laminated composites was discussed.
Association of HLA-G +3142 C>G polymorphism and breast cancer in Tunisian population
HLA-G is highly expressed in cancer. Also, it is associated to its progression. Here, we explored the relationship between two HLA-G polymorphisms with breast cancer (BC) and tried to make a correlation with sHLA-G levels. We genotyped 104 patients with BC and 83 controls (CTRL) for HLA-G 14-bp insertion/deletion (Ins/Del) and HLA-G +3142 C>G polymorphisms. The mutations were identified with PCR and PCR–RFLP. The sHLA-G dosage was performed on plasma samples by a specific ELISA. A significant association with BC was found concerning the G allele in the +3142 C>G polymorphism ( p  = 0.0004). The G/G genotype is the protective genotype (1 % in BC patients vs. 13.1 % in CTRL, OR 0.065, 95 % CI 0.008–0.523). No statistically significant differences were observed for the 14-bp Ins/Del polymorphism between BC patients and controls frequencies. The protection by G/G genotype of +3142 C>G polymorphism is maintained in young patients (<50 years, p  = 0.0006) and in early-diagnosed BC patients (<50 years, p  = 0.0033). In addition, an association was found between the haplotypes inferred by both HLA-G polymorphisms and BC susceptibility. Indeed, the (DelG) haplotype is found as the protective haplotype against BC (OR 0.269, 95 % CI 0.081–0.895, p  = 0.023). The ELISA dosage of sHLA-G revealed increased levels in BC compared to CTRL ( p  < 0.0001). We demonstrated also that sHLA-G is closely associated with advanced stages of BC without significance. sHLA-G is increased in TNM IV and SBR III subgroups. It is also enhanced in patients with a tumor size over 20 mm and in triple-negative patients. Taken together, our findings demonstrate, for the first time, the association of HLA-G +3142 C>G polymorphism with BC susceptibility in Tunisian population. Our results revealed also a potential implication of sHLA-G in advanced stages of BC.
Design and Hydrodynamic Performance of a Horizontal Axis Hydrokinetic Turbine
Marine energy is gaining more and more interest in recent years and, in comparison to fossil energy, is very attractive due to predictable energy output, renewable and sustainable, the Horizontal Axis Hydrokinetic Turbine (HAHT) is one of the most innovative energy systems that allow transforms the kinetic energy into electricity. This work presents a new series of hydrofoil sections, named here NTSXX20, and was designed to work at different turbine functioning requirement. These hydrofoils have excellent hydrodynamic characteristics at the operating Reynolds number. The design of the turbine has been done utilising XFLR5 code and QBlade which is a Blade-Element Momentum solver with a blade design feature. Tidal current turbine has been able to capture about 50% from TSR range of 5 to 9 with maximum CPower of 51 % at TSR=6,5.   The hydrodynamics performance for the CFD cases was presented and was employed to explain the complete response of the turbine.
Numerical Evaluation of Dynamic Response for Flexible Composite Structures under Slamming Impact for Naval Applications
The deformable composite structures subjected to water-entry impact can be caused a phenomenon called hydroelastic effect, which can modified the fluid flow and estimated hydrodynamic loads comparing with rigid body. This is considered very important for ship design engineers to predict the global and the local hydrodynamic loads. This paper presents a numerical model to simulate the slamming water impact of flexible composite panels using an explicit finite element method. In order to better describe the hydroelastic influence and mechanical properties, composite materials panels with different stiffness and under different impact velocities with deadrise angle of 100 have been studied. In the other hand, the inertia effect was observed in the early stage of the impact that relative to the loading rate. Simulation results have been indicated that the lower stiffness panel has a higher hydroelastic effect and becomes more important when decreasing of the deadrise angle and increasing the impact velocity. Finally, the simulation results were compared with the experimental data and the analytical approaches of the rigid body to describe the behavior of the hydroelastic influence.
A new approach to controlling an active suspension system based on reinforcement learning
Active suspension provides better vehicle control and safety on the road with optimal driving comfort compared to passive suspension. Achieving this requires a good control system that can adapt to any environment. This article uses a deep reinforcement learning method to develop an optimal neural network that meets the comfort requirements according to ISO 2631-5 standards. The algorithm trains the agent without any prior knowledge of the environment. Various simulations were performed, and the results were validated with the literature and the standard until the appropriate reward function was found. Simple and consistent road profiles were used while maintaining constant system parameters during training. The results show that suspension based on deep reinforcement learning reduces vehicle body acceleration and improves ride comfort without sacrificing suspension deflection and dynamic tire loading. The controller expects the RMS value of the acceleration to be 0.228 with a minimum overrun of the suspended mass.