RESUMO
Understanding the nature of the interaction between a metal and support, which is known as the metal-support interaction, in supported metal catalysts is crucial to design catalysts with desired properties. Here, we have developed model Pt/TiO2 catalysts based on the deposition of colloidal Pt nanoparticles and studied their atomic and electronic structures before and after a postdeposition treatment that induces catalytic activity using aberration-corrected scanning transmission electron microscopy, electron energy loss spectroscopy, and first-principles calculations. Direct contact between Pt nanoparticles and TiO2 is realized after the postdeposition treatment, which is accompanied by the formation of a Ti3+ state on the TiO2 surface close to the Pt nanoparticles and a Ptδ+ state on the Pt nanoparticles. The origin of these two states and their effect on the catalytic properties are discussed. These findings pave the way for a comprehensive understanding of metal-support interactions in supported metal catalysts.
RESUMO
BACKGROUND: The evaluation of intravitreal bevacizumab treatment for delayed radiation maculopathy and papillopathy after irradiation for maxillary sinus cancer. CASE REPORT: A patient with radiation maculopathy and papillopathy was treated with intravitreal bevacizumab (1.25 mg). Main outcome measures included fundus photography, angiography, and optical coherence tomography (OCT). Two weeks after intravitreal bevacizumab, visual acuity improved from 0.4 to 1.2. Fundus examination revealed decreased disc swelling, peripapillary hemorrhage, and macular edema. OCT demonstrated complete resolution of serous retinal detachment. At the 12-month follow-up, there was no exudation recurrence. No ocular or systemic side effects were observed. CONCLUSION: Intravitreal bevacizumab can be used to treat radiation maculopathy and papillopathy. Antivascular endothelial growth factor therapy may decrease tissue injury associated with radiation vasculopathy.
