Photocatalytic Degradation of Diclofenac Using Al2O3-Nd2O3 Binary Oxides Prepared by the Sol-Gel Method.

This paper reports the sol-gel synthesis of Al2O3-Nd2O3 (Al-Nd-x; x = 5%, 10%, 15% and 25% of Nd2O3) binary oxides and the photodegradation of diclofenac activated by UV light. Al-Nd-based catalysts were analyzed by N2 physisorption, XRD, TEM, SEM, UV-Vis and PL spectroscopies. The inclusion of Nd2O3 in the aluminum oxide matrix in the 10-25% range reduced the band gap energies from 3.35 eV for the γ-Al2O3 to values as low as 3.13-3.20 eV, which are typical of semiconductor materials absorbing in the UV region. γ-Al2O3 and Al-Nd-x binary oxides reached more than 92.0% of photoconverted diclofenac after 40 min of reaction. However, the photocatalytic activity in the diclofenac degradation using Al-Nd-x with Nd2O3 contents in the range 10-25% was improved with respect to that of γ-Al2O3 at short reaction times. The diclofenac photoconversion using γ-Al2O3 was 63.0% at 10 min of UV light exposure, whereas Al-Nd-15 binary oxide reached 82.0% at this reaction time. The rate constants determined from the kinetic experiments revealed that the highest activities in the aqueous medium were reached with the catalysts with 15% and 25% of Nd2O3, and these compounds presented the lowest band gap energies. The experimental results also demonstrated that Nd2O3 acts as a separator of charges favoring the decrease in the recombination rate of electron-hole pairs.

Use of OCT Angiography in Choroidal Melanocytic Tumors.

OBJECTIVE: To describe OCTA findings in choroidal melanocytic tumors, especially the microcirculation patterns, and to try to correlate with the histopathological studies. METHODS: Cross-sectional, comparative, observational study. 70 cases, including 55 choroidal nevi and 15 choroidal melanomas. Three different observers evaluated specific variables in the choriocapillaris layer on AOCT images and searched for images which described histopathologic vascular patterns, and also, a general description of the images was made. Complementary multi-imaging studies included EDI SD-OCT, color and autofluorescence fundus imaging, Doppler ultrasound, and indocyanine/fluorescein angiography. MAIN RESULTS: Good quality studies were acquired in 80% of the cases, with kappa indexes 0.768-0.958. Nevus OCTA images were described mainly as hyperreflective (72.7%), whereas choroidal melanoma as iso/hyporeflective (62.5%). Avascular areas were found in 50.96% and in 33.3% of choroidal nevus and choroidal melanomas, respectively. A neovascular membrane was found only in cases of choroidal nevus (16.3%). Only in cases of choroidal melanomas, we found vascular loops (6.6%) or vascular networks (6.6%). CONCLUSION: OCTA is a promising new technology that can be used to study in vivo the differential characteristics of microcirculations between posterior segment melanocytic lesions. Today, larger studies are needed to corroborate these findings and to correlate it with malignancy.