Comparative study of CuO supported on CeO2, Ce0.8Zr0.2O2 and Ce0.8Al0.2O2 based catalysts in the CO-PROX reaction

CuO supported on CeO2, Ce0.8Zr0.2O2 and Ce0.8Al0.2O2 based catalysts (6%wt Cu) were synthesized and tested in the preferential oxidation of CO in a H2-rich stream (CO-PROX). Nanocrystalline supports, CeO2 and solid solutions of modified CeO2 with zirconium and aluminum were prepared by a freeze-drying method. CuO was supported by incipient wetness impregnation and calcination at 400 C. All catalysts exhibit high activity in the CO-PROX reaction and selectivity to CO2 at low reaction temperature, being the catalyst supported on CeO2 the more active and stable. The influence of the presence of CO2 and H2O was also studied

Re-examination of effects of alumina on bulk and grain boundary conductivities of CGO solid electrolytes

Identification of secondary phases and their dependence on composition and firing conditions were used as guidelines to re-examine effects of alumina on bulk and grain boundary properties of ceria-gadolinia electrolytes. Solubility of alumina may contribute to enhance bulk properties of samples with low contents of gadolinia, probably by enhancing the concentration of oxygen vacancies as prevailing charge carriers. This gain is slightly reverted for excessive addition of Al, probably combining effects of depletion of Gd in the fluorite phase, due to onset of GdAlO3, and microstructural changes. For samples with intermediate contents of Gd one found that alumina affects mainly the grain boundary properties, as a consequence of depletion of Gd, even for relatively low additions of Al, possibly due to heterogeneities induced by preferential location of secondary phases at grain boundaries. Additions of Al may exert a slight positive effect on bulk conductivity of samples with relatively high contents of Gd, i.e., above the composition with highest bulk conductivity. In this case, precipitation of GdAlO3 may contribute to optimize the final composition of the fluorite phase. (C) 2013 Elsevier B.V. All rights reserved

Enfermedad de Eales: a propósito de un caso

Case report: we report a case of a 18 years old man with decreased vision for two days in his right eye. A fundus examination reveals cloudy vitreous and areas of vascular sheathing. Discusión: Eales disease is a uncommon disorder, with typical no perfusion retinal areas. There is a strong association of Eales¿ disease with purified protein derivate skin positivity.Caso clínico: se presenta el cuadro clínico de un varón de 18 años, que acudió a urgencias por visión borrosa de 2 días de evolución en ojo derecho. Funduscopicamente se aprecia turbidez vítrea, así como envainamiento vascular. Discusión: La enfermedad de Eales es una vasculitis poco frecuente, caracterizada por áreas retinianas no perfundidas, y asociada a un mantoux positiv

La Libreta

Se explica un estudio realizado en un centro preferente de integración de alumnado con discapacidad motriz (DM) que pretende conseguir los siguientes objetivos: de un lado conocer y valorar cómo incide la aplicación de estrategias didácticas en la inclusión del alumnado con DM y del otro, conocer y elaborar, como grupo de trabajo, herramientas de observación y análisis de datos que nos permitan reflexionar sobre la práctica docente inclusiva. Se realiza a partir de un modelo A-B formado por dos sesiones, mediatizadas por un proceso colaborativo de formación-acción.ES