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Since recent research indicates that the addition of graphene increases the mechanical and biological properties of calcium phosphates simultaneously, graphene oxide (GO) was used in this research to enhance the properties of brushite cement. The main objective of this study is to investigate the mechanism of nucleation and growth of brushite crystals on GO sheets. Calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as calcium and phosphate precursors. The brushite chemical precipitation method on graphene sheets was used in this study and computer-assisted modeling was used to understand the process. The results of this study showed that the hybrid powders contained brushite and GO. Brushite crystals were grown after nucleation in proportion to the three main planes containing (020), (121¯), and (141). The final particles were plate shaped. The results of setting time tests showed that increasing the GO% decreases the setting time and this trend continues with an increasing amount of GO. The results of the mechanical evaluation showed that increasing the GO by up to 2% increased the mechanical properties and more than that decreased the mechanical properties.

AbstractThe present study was carried out to investigate the effect of γ-irradiation at two irradiation doses of 10 and 25 kGy, on the antibacterial activities of cumin essential oils (E.Os) in vitroand in vivosystems. For this purpose, the cumin seeds were irradiated with Co60 source (0, 10 and 25 kGy) and subjected to Clevenger extraction to obtain E.Os. In vitroantibacterial activities of cumin E.Os was determined on Gram-negative and Gram-positive bacterial strains including E. coli, P. aeroginosa, B. cereusand S. aureususing agar well diffusion method, disk diffusion method and, MIC and MBC determinations. In vivoantibacterial activity was performed on polymicrobial infection induced by cecal ligation and puncture (CLP) in rat through blood colony forming units (CFUs) determination. The results showed that CLP operation caused a marked increase in bacterial load of blood which was reduced in rats treated with fresh and irradiated cumin oils. In vitroresults also showed the sensitivity of all tested bacterial strains against the fresh and irradiated cumin E.Os. These data may suggest that cumin E.O has potential antibacterial activity both in vivoand in vitrosystems. Also, γ-irradiation to cumin seeds at 10 and 25 kGy has no significant effects on the antibacterial properties of cumin E.Os.