RESUMO
An electromagnetic field-assisted (EMF-assisted) laser cladding technique was used to prepare Norem02 iron-based cemented carbide coatings on 304 stainless steels. The coatings then were characterized in terms of their microstructure, microhardness, residual stress, and wear resistance. The results indicated that EMF did not change the phase composition of the Norem02 iron-based cemented carbide coating, but significantly affected its microstructure and properties. EMF accelerated the formation of more uniform and refined microstructure. With an increasing current intensity of EMF to 40 A, the dendritic and columnar crystal structure of the coating gradually transformed into uniform and fine equiaxed grains. However, when the EMF current intensity was increased to 80 A, a small number of small dendrites and columnar crystals began to appear at the top and bottom of the coating. Accordingly, the microhardness first increased, then decreased, and achieved a max of 376.9 HV0.2 at EMF current intensity of 40 A. EMF also improved the wear resistance of the coatings, reduced the cracking sensitivity, and reduced residual stress on the surface by 45.2%.
RESUMO
Exogenous insulin therapy is the mainstay treatment for Type-1 diabetes (T1D) caused by insulin deficiency. A fine-tuned insulin supply system is important to maintain the glucose homeostasis. In this study, we present a designed cell system that produces insulin under an AND gate control, which is triggered only in the presence of both high glucose and blue light illumination. The glucose-sensitive GIP promoter induces the expression of GI-Gal4 protein, which forms a complex with LOV-VP16 in the presence of blue light. The GI-Gal4:LOV-VP16 complex then promotes the expression of UAS-promoter-driven insulin. We transfected these components into HEK293T cells, and demonstrated the insulin was secreted under the AND gate control. Furthermore, we showed the capacity of the engineered cells to improve the blood glucose homeostasis through implantation subcutaneously into Type-1 diabetes mice.
RESUMO
Juglone is a plant-derived 1,4-naphthoquinone with confirmed antibacterial activity. However, the mechanism of action of juglone against Staphylococcus aureus remains unclear. Possible mechanisms were explored by a proteomic analysis of S. aureus proteins that are inhibited by juglone. Two-dimensional gel electrophoresis revealed that 21 protein spots were differentially expressed between juglone-treated and untreated cells of which 13 were identified. A bioinformatic analysis revealed that proteins participating in protein synthesis, the tricarboxylic acid cycle, as well as DNA and RNA synthesis were inhibited by juglone, thus leading to cell collapse. These findings provide clues regarding the mechanism of action of juglone, which can be effective for treating cases of S. aureus infection.
