Penicillin in oral aphthosis, new insight for an old drug: A randomized, double-blind, controlled clinical trial.

Background: Oral aphthosis is a painful ulceration of mucus membranes characterized by round or oval lesions with central necrosis and erythematous haloes. Due to unknown etiology, treatment is highly controversial and based mainly on individual experience. The aim of this study was to investigate the safety and efficacy of topical penicillin 6.

First-principles study of bandgap effects in graphene due to hydrogen adsorption.

Hydrogen adsorption on graphene in commensurate periodic arrangements leads to bandgap opening at the Dirac point and the emergence of dispersionless midgap bands. We study these bandgap effects and their dependence on periodicity for a single hydrogen adsorbate on periodic graphene supercells using spin-polarized density-functional theory calculations. Our results show that for certain periodicities, marked by a scale factor of three, the bandgap is suppressed to a great extent, and has a special level structure around the neutrality point.