SUN2 contributes to vascular smooth muscle cell alterations induced by matrix rigidity

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A Statistical Analysis of Size, Shape and Tensile Properties of Fibres Extracted from Date Palm (Phoenix Dactylifera L.) Rachis

Algeria is the largest country in Africa by in terms of land area, which makes it contain large quantities of agricultural residues. The aim of this study is the valorisation of the huge amount of agricultural residue of date palm rachis available in Algeria to be used as reinforcement in bio-composite materials for various industrial applications. The analysis of the morphology of the of the date palm rachis cross-section allowed us to identify two main types of fibres according to their microstructure: vascular bundles and fibre strands. The chemical and molecular structure analysis of the date palm rachis fibres was examined by Fourier transform infrared spectroscopy (FTIR). The tensile properties of the fibre extracted were investigated under tensile loading test. The experimental results obtained for the tensile strength, Young’s modulus and strain at break of the fibres have been analysed, because of their dispersion, using three-parameter and two-parameter Weibull statistical laws. The tensile strength and Young’s modulus of the fibre strand were found to be about than four times higher than for the vascular bundle and their predicted model was determined. The tensile properties obtained for the investigated fibre were compared with other lignocelluloses fibres, existing in the literature, and it shows its great potential for use as reinforcement in bio-composite materials

Cellular and Molecular Responses to Gravitational Force-Triggered Stress in Cells of the Immune System

Sensitivity of the human immune system to microgravity has been supposed since the first Apollo missions and was demonstrated during several space missions in the past. In vitro experiments demonstrated that cells of the immune system are exceptionally sensitive to microgravity. Therefore, serious concerns arose whether spaceflight-associated immune system weakening ultimately precludes the expansion of human presence beyond Earth’s orbit. In human cells, gravitational forces may be sensed by an individual cell in the context of altered extracellular matrix mechanics, cell shape, cytoskeletal organization, or internal prestress in the cell–tissue matrix. The development of cellular mechanosensitivity and signal transduction was probably an evolutionary requirement to enable our cells to sense their individual microenvironment. Therefore it is possible that the same mechanisms, which enable human cells to sense and to cope with mechanical stress, are potentially dangerous in microgravity. This chapter reviews the most recent developments in investigation to elucidate the influence of microgravity on immune cell signaling and functions and hereby bridges the phenotypic changes to transcriptome and epigenetic regulators