Electrospun TiO(2) fiber composite photoelectrodes for water splitting.

This work has focused on the development of electrospun TiO2 fiber composite photoelectrodes for hydrogen production by water splitting. For comparison, similar photoelectrodes were also developed using commercial TiO2 (Aeroxide P25) nanoparticles (NPs). Dispersions of either fibers or P25 NPs were used to make homogenous TiO2 films on fluorine-doped SnO2 (FTO) glass substrates by a doctor blade (DB) technique. Scanning electron microscopy (SEM) analysis revealed a much lower packing density of the DB fibers, with respect to DB-P25 TiO2 NPs; this was also directly reflected by the higher photocurrent measured for the NPs when irradiating the photoelectrodes at a light intensity of 1.5AM (1 sun, 1000 W/m(2)). For a better comparison of fibers vs. NPs, composite photoelectrodes by dip-coating (onto FTO) TiO2 sol-gel (SG) matrixes containing an equal amount (5 or 20 wt %) of either fibers or P25 NPs were also investigated. It emerged that the photoactivity of the fibers was significantly higher. For composites containing 5 wt % TiO2 fibers, a photocurrent of 0.5 mA/cm(2) (at 0.23 V vs Ag/AgCl) was measured, whereas 5 wt % P25 NPs only provided 0.2 mA/cm(2). When increasing to 20 wt % fibers or NPs, the photocurrent decreased, because of the formation of microcracks in the photoelectrodes, because of the shrinkage of the sol-gel. The high photoactivity of the fiber-based electrodes could be confirmed by incident photon to current efficiency (IPCE) measurements. Remarkably, the IPCE of composites containing 5 wt % fibers was between 35% and 40% in the region of 380-320 nm, and when accounting for transmission/reflection losses, the absorbed photon to current efficiency (APCE) was consistently over 60% between 380 nm and 320 nm. The superior photoactivity is attributed to the enhanced electron transport in the electrospun fibers, with respect to P25 NPs. According to this study, it is clear that the electronic connectivity ensured by the sol-gel also contributes positively to the enhanced photocurrent.

Immunomodulatory activity of ouabain in Leishmania leishmania amazonensis-infected Swiss mice.

Ouabain is a cardiotonic steroid identified as an endogenous substance of human plasma, being produced by the adrenal, pituitary, and hypothalamus. Despite the studies demonstrating the ability of ouabain to modulate inflammation and other aspects of the immune response, the effects of this substance in Leishmaniasis is unknown. The purpose of this work was to understand the immunomodulatory activity of ouabain in experimental Leishmaniasis in Swiss mice. It was demonstrated that ouabain reduced total cell numbers in the peritoneal cavity as a reflex of the inhibition of neutrophil migration induced by Leishmania (L.) Amazonensis. Furthermore, ouabain reduced TNF-α and IFN-γ levels, without cytotoxicity against peritoneal macrophages. These data showed the anti-inflammatory role of ouabain in the early events of the immune response triggered by Leishmania (L.) Amazonensis infection in murine model.

[Smoking prevalence at the Federal University of São Paulo, 1996--preliminary data of an institutional program]. / Prevalência de tabagismo na Universidade Federal de São Paulo, 1996--dados preliminares de um programa institucional.

PURPOSE: To evaluate the prevalence of tobacco smoking among health workers, professores, nurses and students of Federal University of São Paulo and the acceptance of an institutional program for quitting smoking. METHODS: We analized the answers of a questionnairy with 51 questions, distributed to people from different categories. RESULTS: The total percentage of answered questionnaires was 48.6% (2613). The answers obtained from health workers were 37.3%, professors 49.0%, nurses 52.7% and students 76.5% The total percentage of smokers at UNIFESP was 15.5%:23.7% for health workers, 18% for professors, 16% for nurses and 8.6% for students. There was no significant statistical difference between the prevalence of smoking among females (17.3%) and males (16.3%). The age of major prevalence of smoking was between 31 to 40 years (26.6%). For all ages, people who have university level smoked less, independent of sex. Eighty three percent (83%) of the UNIFESP workers and students are worried of being passive smokers. Between the smokers, 55% were thinking of quiting and 42% declared that need some help to quit. CONCLUSION: We concluded that educational programs and help for cessation at institutional level are necessary and well accepted at UNIFESP, and the completion of these programs will contribute to the obeying of the prohibitive laws of no smoking within the community.

Prevalência de tabagismo na Universidade Federal de Säo Paulo, 1996: dados preliminares de um programa institucional / Smoking prevalence at Universidade Federal de Säo Paulo, 1996: preliminary data of an institutional program

Objetivo. O conhecimento da prevalência do tabagismo é necessário para a realizaçao de programas institucionais adequados que visem a diminuiçao do número de fumantes. O objetivo do trabalho foi verificar a prevalência do tabagismo entre funcionários, docentes, enfermeiros e alunos da Universidade Federal de Sao Paulo e a aceitabilidade de um programa antifumo. Pacientes e Métodos. Foram analisadas as respostas obtidas a partir de um questionário contendo 51 questoes, distribuídos para as diferentes categorias. Resultados. A porcentagem total de questionários respondidos foi de 48,6 por cento (2.613) sendo 37,3 por cento para funcionários, 49,0 por cento para docentes, 52,7 por cento para enfermeiras e 76,5 por cento para alunos. Verificou-se que a porcentagem total de fumantes na UNIFESP foi de 15,5 por cento, sendo 23,7 por cento entre funcionários, 18 por cento entre docentes, 16 por cento entre enfermeiros e 8,6 por cento entre alunos. A faixa etária de maior prevalência de fumantes foi a de 31 a 40 anos (26,6 por cento). Nao houve diferença estatística entre a prevalência de fumantes entre homens e mulheres. Em ambos os sexos, para todas as faixas etárias, os indivíduos com maior nível de instruçao fumavam menos. Das pessoas que responderam o questionário, 82,5 por cento estavam preocupadas em serem fumantes passivas. Dos fumantes, 55 por cento estao pensando em largar de fumar e 42 por cento julgam precisar de algum tipo de ajuda. Conclusao. Programas educacionais e de cessaçao do tabagismo em nível institucional sao necessários e bem aceitos na UNIFESP, devendo ser realizados para que as leis de restriçao do fumo dentro da instituiçao sejam efetivamente cumpridas.