Synthesis of Copper Nanowires and Their Antimicrobial Activity on Strains Isolated Persistent Endodontic Infections.

Copper nanowires, Cu-NWs may have a good antimicrobial effect in endodontic treatment. The objective of this work was to synthesize, characterize and evaluate the antibacterial activity of Cu-NWs on strains obtained from human root canal. A wide distribution of Cu-NWs diameters from 30 to 90 nm was obtained with lengths ranging from 5 to 40 µm. Structural analysis of Cu-NWs showed crystalline planes, which corresponded to Cu, with preferential growth in the direction [110]. The geometric mean MICs was of 289.30 µg/mL, with a MIC50 of 256 µg/mL and a MIC90 of 512 µg/mL for Cu-NWs. Cellular viability of 28 a biofilm tends to decrease the longer it is exposed to Cu-NWs. Synthesized and characterized Cu-NWs have a good antimicrobial effect against clinical strains used in the present study and has a potential to be used for disinfection of the root canal system.

Towards recycling of waste carbon fiber: Strength, morphology and structural features of recovered carbon fibers.

Carbon fiber is one of the most widely used materials in high demand applications due to its high specific properties, however, its post-recycling properties limit its use to low performance applications. In this research, the carbon fiber recovering is examined using two methods: two-step pyrolysis and microwave-assisted thermolysis. The results indicate that the fibers recovered by pyrolysis show reduced surface and structural damage, maintaining the original mechanical properties of the fiber with losses below 5%. The fibers recovered by microwaves undergo significant surface changes that reduce their tensile strength by up to 60% and changes in their graphitic structure, increasing their degree of crystallinity by Raman index ID/IG from 1.98 to 2.86 and their amorphous degree by ID"/IG ratio from 0.411 to 1.599. Recovering fibers from microwave technique is 70% faster compared to two step pyrolysis, and provides recycled fibers with superior surface activation with the presence of polar functional groups -OH, -CO, and -CH that react with the epoxy matrix. The thermal, morphological, structural and mechanical characterizations of the recovered fibers detailed in this work provide valuable findings to evaluate their direct reuse in new composite materials.