Controlling the Phase Transformation of Alumina for Enhanced Stability and Catalytic Properties.

Current transition alumina catalysts require the presence of significant amounts of toxic, environmentally deleterious dopants for their stabilization. Herein, we report a simple and novel strategy to engineer transition aluminas to withstand aging temperatures up to 1200 °C without inducing the transformation to low-surface-area α-Al2O3 and without requiring dopants. By judiciously optimizing the abundance of dominant facets and the interparticle distance, we can control the temperature of the phase transformation from θ-Al2O3 to α-Al2O3 and the specific surface sites on the latter. These specific surface sites provide favorable interactions with supported metal catalysts, leading to improved metal dispersion and greatly enhanced catalytic activity for hydrocarbon oxidation. The results presented herein not only provide molecular-level insights into the critical factors causing deactivation and phase transformation of aluminas but also pave the way for the development of catalysts with improved activity for catalytic hydrocarbon oxidation.

Treatment of branchial cleft cyst with intracystic injection of OK-432.

CONCLUSIONS: The data suggest that branchial cleft cyst (BCC) can be primarily treated with OK-432 sclerotherapy and only the remaining lesions with excision. OBJECTIVES: To evaluate the effectiveness of sclerotherapy using OK-432 in the treatment of BCC. MATERIALS AND METHODS: We treated 12 BCC patients (3 males and 9 females; mean age 25 years) with OK-432 sclerotherapy at an outpatient clinic. The cystic fluids were aspirated and diagnosed by cytomorphology and DNA cytometric analysis to exclude malignancy. The fluid aspirated from the cyst was replaced with an equal volume of OK-432 solution. The sizes of cysts were measured and compared before and after injection. The remaining cysts were excised and histopathologically compared with the excised BCCs that had not been treated with OK-432. RESULTS: Seven of 12 patients (58%) showed a complete response after OK-432 injection, administered one to three times. Three patients (25%) had only partial response and two (17%) were stationary. Five patients with remaining lesions underwent excision. There was no difficulty in dissecting around the cysts and no increased morbidity during operation. None of the patients had evidence of recurrences or malignancies developing during the follow-up period (mean 21 months, range 17-26 months). There were no major side effects except fever after sclerotherapy.