································································································································································································································Abstract In this study, an aluminum oxide layer for sealing treatment of nano-diamond powder was synthesized by anodizing under constant current. The produced pore size and oxide thickness were investigated using scanning electron microscopy. The pore size increased as the treatment time increased, current density increased, sulfuric acid concentration decreased, which is different from the results under constant voltage, due to a dissolution of the oxide layers. The oxide layer thickness by the anodizing increased as temperature, time, and current density increased. The results of this study can be applied to optimize the sealing treatment process of nano-diamond particles of 4-10 nm to enhance the resistances of corrosion and wear of the matrix.
This study investigated optimal extraction conditions for application of Ulmus pumila L. as a natural antioxidant. U. pumila L. was extracted using ethanol (EtOH) at various concentrations (0, 40, and 80%) and extraction times (1, 2, and 3 h) at 70°C and then evaluated for extraction yield, total phenolic contents, total flavonoid contents, as well as antioxidant activities [2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, reducing power, and oxygen radical absorbing capacity (ORAC)]. Antioxidant activities were correlated with total phenolic and flavonoid contents. Of the solvent conditions, 80% EtOH extracts for 3 h at 70°C showed the highest total phenolic and flavonoid contents with strong antioxidant activities, although there were no significant time effects on DPPH and ABTS radical scavenging activities and reducing power. However, ORAC values of all EtOH extracts remarkably increased in a time-dependent manner. In addition, 80% EtOH extract for 3 h exhibited strong antioxidant effects on HDF and 3T3-L1 cells. Therefore, the antioxidant capacity of U. pumila L., may due to phenolic and flavonoid contents, and extraction conditions were 80% EtOH for 3 h at 70°C. This extract could be a good source for natural antioxidants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.