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ZrB2–SiC coating on C/C composites was prepared through vapor silicon infiltration process. The coated C/C composites showed excellent oxidation performance at 1500°C. Isothermal oxidation results showed that there was weight gain accompanied in the whole oxidation process and no evidence of oxidation of C/C composite substrate was observed. The thickness of coating increased from 120 μm to about 200 μm after oxidizing at 1500°C. Three distinct layers could be observed in the coating, namely, outer SiO2‐rich layer, middle ZrB2‐rich layer, and inner SiC‐rich layer. ZrB2 particles were coarsened after oxidation.

Elemental sulfur‐promoted cyclization for the one‐pot synthesis of tetra‐substituted imidazoles from benzylamines and ketones is described. Elemental sulfur combined with molecular oxygen as the benign co‐oxidant was found to be the key for the high efficiency of this transformation under metal‐free conditions. A range of tetrasubstituted imidazoles were synthesized from simple ketones and amines with good functional group tolerance.magnified image

In order to prevent postoperative adhesion and the related complications, a thermally crosslinked gelatin (TCG) film was developed and the basic biological properties were examined, paying special attention to the relationship between these properties and the extent of crosslinking of the film. The gelatin films crosslinked thermally for five different time periods (0, 1, 3, 8, and 14 hours) were developed and the following tests were performed. Regarding the material characterization of the films, the water content, the water solubility, and the enzymatic degradation for collagenase were found to be closely related to the duration of thermal crosslinking. In an in vitro study conducted to examine the cell growth of fibroblasts cultured on the films, the degree of cell growth, except no crosslinked film, was less than that observed in the control group, thus suggesting that such effects of the films on fibroblast cell growth may be related with their anti-adhesive effects. In in vivo tests, the films crosslinked for longer time periods (3, 8, and 14 hours) were retained for longer after being implanted into the abdominal cavity in rats and showed a significant anti-adhesive effect in the rat cecum adhesion models, indicating that the biodegradability and anti-adhesive effects of the TCG films depend on the duration of thermal crosslinking. In order to develop useful and effective anti-adhesive gelatin film, it is very important to optimize duration of the thermal crosslinking.