Study of blister formation in GRP laminates in water

Glass fibre reinforced polyesters (GRP) are widely used in boat and swimming pool manufacture. One drawback for these materials is that they may develop blistering after prolonged and continuous contact with water. The aim of the research programme reported in this thesis is to understand the fundamental reasons for the blister formation, as well as the factors affecting it. Various polyester resins, epoxy resin, vinyl ester resin, different chopped strand glass mats (CSM) and initiators were used for GRP laminates and blister trials carried out. Blisters were examined visually and by an optical microscope; they are classified into four groups according to their origins: (1) contaminants, (2) bubbles, (3) pre-cracks, (4) glass fibre bundles. Detailed study of their relative importance shows that the last two categories are most significant. [Continues.

Study of blister formation in GRP laminates in water

Glass fibre reinforced polyesters (GRP) are widely used in boat and swimming pool manufacture. One drawback for these materials is that they may develop blistering after prolonged and continuous contact with water. The aim of the research programme reported in this thesis is to understand the fundamental reasons for the blister formation, as well as the factors affecting it. Various polyester resins, epoxy resin, vinyl ester resin, different chopped strand glass mats (CSM) and initiators were used for GRP laminates and blister trials carried out. Blisters were examined visually and by an optical microscope; they are classified into four groups according to their origins: (1) contaminants, (2) bubbles, (3) pre-cracks, (4) glass fibre bundles. Detailed study of their relative importance shows that the last two categories are most significant. [Continues.

Enhanced Cell Osteogenesis and Osteoimmunology Regulated by Piezoelectric Biomaterials with Controllable Surface Potential and Charges

Bone regeneration is a well-orchestrated process involving electrical, biochemical, and mechanical multiple physiological cues. Electrical signals play a vital role in the process of bone repair. The endogenous potential will spontaneously form on defect sites, guide the cell behaviors, and mediate bone healing when the bone fracture occurs. However, the mechanism on how the surface charges of implant potentially guides osteogenesis and osteoimmunology has not been clearly revealed yet. In this study, piezoelectric BaTiO3/β-TCP (BTCP) ceramics are prepared by two-step sintering, and different surface charges are established by polarization. In addition, the cell osteogenesis and osteoimmunology of BMSCs and RAW264.7 on different surface charges were explored. The results showed that the piezoelectric constant d33 of BTCP was controllable by adjusting the sintering temperature and rate. The polarized BTCP with a negative surface charge (BTCP−) promoted protein adsorption and BMSC extracellular Ca2+ influx. The attachment, spreading, migration, and osteogenic differentiation of BMSCs were enhanced on BTCP–. Additionally, the polarized BTCP ceramics with a positive surface charge (BTCP+) significantly inhibited M1 polarization of macrophages, affecting the expression of the M1 marker in macrophages and changing secretion of proinflammatory cytokines. It in turn enhanced osteogenic differentiation of BMSCs, suggesting that positive surface charges could modulate the bone immunoregulatory properties and shift the immune microenvironment to one that favored osteogenesis. The result provides an alternative method of synergistically modulating cellular immunity and the osteogenesis function and enhancing the bone regeneration by fabricating piezoelectric biomaterials with electrical signals

Polypyrrole-Wrapped SnS₂ Vertical Nanosheet Arrays Grown on Three-Dimensional Nitrogen-Doped Porous Graphene for High-Performance Lithium and Sodium Storage

The two-dimensional layered material tin disulfide (SnS2) has a high theoretical capacity for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) due to its combination of conversion and alloying reactions during the charge-storage process. However, the intrinsic poor conductivity and huge volume changes impede its practical applications. In this work, a design of in situ growth and polymerization is developed to synthesize polypyrrole wrapped SnS2 vertical nanosheet arrays grown on nitrogen-doped three-dimensional graphene (PPy@SnS2@N3DG). The PPy@SnS2@N3DG composite, with the unique free-standing hierarchical structure and the synergy of three components, exhibits excellent rate capability and superior cycling stability. Based on the features of high capacity, lightweight, and facile preparation, the PPy@SnS2@N3DG composite can be considered as a promising electrode for energy storage devices

Selective Inhibition of Matrix Metalloproteinase Isozymes and in Vivo Protection against Emphysema by Substituted γ-Keto Carboxylic Acids

The synthesis and matrix metalloproteinase (MMP) inhibitory activity of a series of γ-keto carboxylic acids are described. Among nine MMP isozymes tested, compound 1j displays selective inhibition of MMP-2, -9, and -12 with IC50 values between 0.20 and 1.51 μM, and in male golden Syrian hamsters, it shows protection against PPE-induced emphysema

data_sheet_1_Inducible T-Cell Co-Stimulator Impacts Chronic Graft-Versus-Host Disease by Regulating Both Pathogenic and Regulatory T Cells.PDF

<p>The incidence of chronic graft-versus-host disease (cGVHD) is on the rise and still the major cause of morbidity and mortality among patients after allogeneic hematopoietic stem cell transplantation (HCT). Both donor T and B cells contribute to the pathogenesis of cGVHD. Inducible T-cell co-stimulator (ICOS), a potent co-stimulatory receptor, plays a key role in T-cell activation and differentiation. Yet, how ICOS regulates the development of cGVHD is not well understood. Here, we investigated the role of ICOS in cGVHD pathogenesis using mice with germline or regulatory T cell (Treg)-specific ICOS deficiency. The recipients of ICOS^−/− donor grafts had reduced cGVHD compared with wild-type controls. In recipients of ICOS^−/− donor grafts, we observed significant reductions in donor T follicular helper (Tfh), Th17, germinal center B-cell, and plasma cell differentiation, coupled with lower antibody production. Interestingly, Tregs, including follicular regulatory T (Tfr) cells, were also impaired in the absence of ICOS. Using ICOS conditional knockout specific for Foxp3⁺ cells, we found that ICOS was indispensable for optimal survival and homeostasis of induced Tregs during cGVHD. Furthermore, administration of anti-ICOS alleviated cGVHD severity via suppressing T effector cells without affecting Treg generation. Taken together, ICOS promotes T- and B-cell activation and differentiation, which can promote cGVHD development; however, ICOS is critical for the survival and homeostasis of iTregs, which can suppress cGVHD. Hence, ICOS balances the development of cGVHD and could offer a potential target after allo-HCT in the clinic.</p