Effect of Phase Contrast and Geometrical Parameters on Bending Behavior of Sandwich Beams with FG Isotropic Face Sheets

Our work is to study the bending behavior of sandwich beams with functional gradient by constituting an isotropic material whose material properties vary smoothly in the z direction only (FGM), where the central layer presents purely a homogeneous and isotropic ceramic. The mechanical properties of FG sandwich beams are assumed to be progressive in thickness according to a power law (P-FGM). Generally, the principle of virtual works is used to obtain the equilibrium equations, and their solutions are obtained based on Navier's solution technique. The present model is based on a shear deformation theory of 2D and 3D beams which contains four unknowns to extract the equilibrium equations of FG sandwich beams. In addition, analytical solutions for bending are used and numerical models are presented to verify the accuracy of the present theory. All the results obtained show that the stiffness of the FG beam decreases as a function of the increase in the volume fraction index k, leading to an increase in the deflections. However, FG beams become flexible by increasing the proportion of the metal to the ceramic part. Furthermore, the influences of material volume fraction index, layer thickness ratio, side-to-height ratio, and the effect of the phase contrast, on the deflections, normal and shear stress of simply supported sandwich FG beams are taken into investigation and discussed in detail. Finally, all our results obtained are in agreement with other previous theoretical works

CX3CR1 knockout aggravates Coxsackievirus B3-induced myocarditis

Studies on inflammatory disorders elucidated the pivotal role of the CX3CL1/CX3CR1 axis with respect to the pathophysiology and diseases progression. Coxsackievirus B3 (CVB3)-induced myocarditis is associated with severe cardiac inflammation, which may progress to heart failure. We therefore investigated the influence of CX3CR1 ablation in the model of acute myocarditis, which was induced by inoculation with 5x105 plaque forming units of CVB3 (Nancy strain) in either CX3CR1-/- or C57BL6/j (WT) mice. Seven days after infection, myocardial inflammation, remodeling, and titin expression and phosphorylation were examined by immunohistochemistry, real-time PCR and Pro-Q diamond stain. Cardiac function was assessed by tip catheter. Compared to WT CVB3 mice, CX3CR1-/- CVB3 mice exhibited enhanced left ventricular expression of inflammatory cytokines and chemokines, which was associated with an increase of immune cell infiltration/presence. This shift towards a pro- inflammatory immune response further resulted in increased cardiac fibrosis and cardiomyocyte apoptosis, which was reflected by an impaired cardiac function in CX3CR1-/- CVB3 compared to WT CVB3 mice. These findings demonstrate a cardioprotective role of CX3CR1 in CVB3-infected mice and indicate the relevance of the CX3CL1/CX3CR1 system in CVB3-induced myocarditis

Strategies for optimizing the mechanical strengths of raw earth-based mortars

International audienc

Нова теорія високого порядку для аналізу температури жолоблення функціонально градуйованих сендвіч-пластин, що спираються на пружну основу

Використовуючи теорію високого порядку (HSDT), у роботі представлено дослідження термічного жолоблення функціонально градуйованих (FG) сендвіч-пластин, підданих різному підвищенню температури по всій їх товщині, що спираються на двопараметричну пружну основу. Передбачається, що механічні властивості FG сендвіч-пластин поступово змінюються з товщиною відповідно до степеневого закону (P-FGM). Проміжний шар однорідний і виготовлений з чисто керамічного матеріалу. Принцип віртуальних робіт використовується для отримання рівнянь стійкості, розв’язки яких отримують на основі методики розв’язування рівнянь Нав’є. Отримані результати порівнюються з результатами інших досліджень. Потім проводиться параметричне дослідження для вивчення впливу геометричних і механічних характеристик, таких як співвідношення розмірів (ширина, довжина і товщина), індекс матеріалу (k) та вплив пружної основи на критичну температуру жолоблення.Using a high order theory (HSDT), this work presents a study of thermal buckling of functionally graded (FG) sandwich plates subjected to various temperature rises across their thickness and resting on a twoparameter elastic foundation. The mechanical properties of the FG sandwich plates are supposed to change gradually through the thickness according to a power law (P-FGM). The intermediate layer is homogeneous and made of a purely ceramic material. The principle of virtual works is used to obtain stability equations, and their solutions are obtained based on Navier’s solution technique. The obtained results are compared with other studies in the literature. Then, a parametric study is conducted to investigate the influence of geometric and mechanical characteristics such as the ratios of dimensions (width, length, and thickness), the material index (k), and the effect of the elastic foundation on the critical buckling temperature

Rapid screening and characterization of bacteria associated with hospital cockroaches ( Blattella germanica L.) using MALDI‐TOF mass spectrometry

International audienc

Diversity and enzymatic potential of thermophilic bacteria associated with terrestrial hot springs in Algeria

21 páginas.- 7 figuras.- 1 tablas.- 96 referencias.- Electronic supplementary material The online version of this article (https://doi.org/10.1007/s42770-020-00376-0) contains supplementary material, which is available to authorized users.This study aims to determine the diversity of culturable thermophilic bacteria isolated from eight terrestrial hot springs in Northeastern of Algeria using the conventional methods, SDS-PAGE fingerprinting of whole-cell proteins and 16S rRNA gene sequencing. In addition, their hydrolytic enzyme activities were also investigated. A total of 293 strains were isolated from the hot springs’ water and sediment using different culture media. Overall, five distinct bacterial groups were characterized by whole-cell protein pattern analysis. Based on the 16S rRNA gene sequencing of 100 selected strains, the isolates were assigned to the following three major phyla: Firmicutes (93%), Deinococcus-Thermus (5%), and Actinobacteria (2%), which included 27 distinct species belonging to 12 different phylotypes, Aeribacillus, Aneurinibacillus, Anoxybacillus, Bacillus, Brevibacillus, Geobacillus, Laceyella, Meiothermus, Saccharomonospora, Thermoactinomyces, Thermobifida, and Thermus. The screening for nine extracellular enzymes showed that 65.87% of the isolates presented at least five types of enzyme activities, and 6.48% of strains combined all tested enzymes (amylase, cellulase, pectinase, esculinase, protease, gelatinase, lipase, lecithinase, and nuclease). It was found that Bacillus, Anoxybacillus, Aeribacillus, and Aneurinibacillus were the genera showing the highest activities. Likewise, the study showed an abundant and diverse thermophilic community with novel taxa presenting a promising source of thermozymes with important biotechnological applications. This study showed that a combined identification method using SDS-PAGE profiles of whole-cell proteins and subsequent 16S rRNA gene sequence analysis could successfully differentiate thermophilic bacteria from Algerian hot springs.Peer reviewe