Preparation and characterization of erbium and ytterbium co-doped sol-gel SiO2 : HfO2 films for planar waveguides

This work reports on the preparation of erbium and ytterbium co-doped SiO2:HfO2 single mode planar waveguides using the sol-gel method. Silica nanoparticles were prepared from tetraethylorthosilicate in basic media and the films were characterized by transmission electron microscopy, scanning electron microscopy, mechanical profilometry, M-lines spectroscopy based on prism coupling technique, X-ray diffractometry, infrared spectroscopy and photoluminescence spectroscopy. The film thicknesses and the refractive indexes were adjusted in order to satisfy a future efficient coupling to single mode optical fiber. Films suitable for both weak and strong light confinement were prepared varying hafnia concentration into the silica matrix. The lifetime values of erbium I-4(13/2) state were measured in order to investigate the influence of clustering and hydroxyl groups on the fluorescence quantum efficiency of the I-4(13/2) level, responsible for the emission at 1.55 mu m attributed to the I-4(13/2) -> I-4(15/2) transition. The high lifetime values suggest the absence of erbium clusters and the elimination of hydroxyl groups by rapid thermal process. (c) 2007 Elsevier B.V. All rights reserved.30460060

Synergic effect of allopurinol in combination with nitro-heterocyclic compounds against Trypanosoma cruzi.

Combination therapy has gained attention as a possible strategy for overcoming the limitations of the present therapeutic arsenal for Chagas disease. The aim of this study was to evaluate the effect of allopurinol in association with nitroheterocyclic compounds on infection with the Y strain of Trypanosoma cruzi. The in vitro effect of allopurinol plus benznidazole or nifurtimox on intracellular amastigotes in infected H9c2 cells was assessed in a 72-h assay. The interactions were classified as synergic for both allopurinol-nifurtimox (sums of fractional inhibitory concentrations [FICs] 0.49 0.08) and allopurinol-benznidazole (FICs 0.48 0.09). In the next step, infected Swiss mice were treated with allopurinol at 30, 60, and 90 mg/kg of body weight and with benznidazole at 25, 50, and 75 mg/kg in monotherapy and in combination at the same doses; as a reference treatment, another group of animals received benznidazole at 100 mg/kg. Allopurinol in monotherapy led to a smaller or nil effect in the reduction of parasite load and mortality rate. Treatment with benznidazole at suboptimal doses induced a transient suppression of parasitaemia with subsequent relapse in all animals treated with 25 and 50 mg/kg and in 80% of those that received 75 mg/kg. Administration of the drugs in combination significantly increased the cure rate to 60 to 100% among mice treated with benznidazole at 75 mg/kg plus 30, 60, or 90 mg/kg of allopurinol. These results show a positive interaction between allopurinol and benznidazole, and since both drugs are commercially available, their use in combination may be considered for the assessment in the treatment of Chagas disease patients

Formação em ciências da saúde: diálogos em saúde coletiva e a educação para a cidadania Health sciences education: dialogues in public health and the education for the citizenship

Nas últimas décadas, tem havido discussões acerca do processo de formação de profissionais da saúde no Brasil. Os temas tratados se baseiam na constatação de pontos precários em relação a uma formação que deveria se voltar ao atendimento das demandas da população, para os princípios do SUS e uma compreensão ampliada da saúde. Buscamos pensar alternativas em relação à graduação nas ciências da saúde e analisar de que maneira esta formação se inscreve no contexto do ensino superior.<br>In the last decades there have been discussions concerning the educational process of health professionals in Brazil. The discussed subjects are based on the verification of precarious aspects concerning a kind of formation that should be focused on attending the demands of the population, on the principles of SUS and an extended understanding of healthcare. We intended to think about alternatives in relation to the graduation in health sciences and in analyzing the way education in health is registered in the context of higher education