Resumo Os óxidos de molibdênio são materiais tecnológicos muito interessantes, que apresentam diversos usos industriais. A adição de um segundo metal pode melhorar suas propriedades catalíticas, bem como alterar o comportamento eletrônico. Várias metodologias para adicionar um segundo metal podem ser encontradas na literatura, porém a comparação entre elas é dificilmente encontrada. Aqui duas rotas de processamento foram aplicadas para a síntese de óxido de molibdênio com adição de cobalto: via sólida e via úmida. Molibdato de amônio e nitrato de cobalto foram usados como materiais de partida e a adição de cobalto foi realizada antes da calcinação. Os materiais iniciais foram caracterizados por MEV, FTIR, FRX e DRX. Os produtos de calcinação foram avaliados por MEV, FRX, DRX e espectroscopia UV-vis. Produto calcinado cuja dopagem foi realizada via estado sólido apresentou menor tamanho de cristal (~25 nm), maior retenção de cobalto (desvio, δ ~10%) e band gap levemente menor em comparação com aquele dopado por via úmida (~40 nm e δ>11%).

Abstract Molybdenum oxides are very interesting technologic materials, which present several industrial uses. The addition of a second metal may enhance its catalytic properties as well as change electronic behavior. Several methodologies for adding a second metal can be found in the literature, however, the comparison between them is hardly ever found. Here two processing routes were tested for the synthesis of molybdenum oxide with cobalt addition: solid-state and wet routes. Ammonium molybdate and cobalt nitrate were used as starting materials and cobalt addition was carried out before calcination. Starting materials were characterized by SEM, FTIR, XRF, and XRD. Calcination products were evaluated by SEM, XRF, XRD and UV-vis spectroscopy. Calcined products whose doping was performed via solid-state presented smaller crystal size (~25 nm), larger cobalt retention (deviation, δ ~10%) and slightly smaller band gap in comparison to those doped via the wet route (~40 nm and δ>11%).

Resumo Zeólitas LTA e FAU foram sintetizadas com brometo de cetiltrimetilamônio (CTAB) visando avaliar os efeitos das razões Si/Al, Na/Al e H2O/Al, do tempo e da temperatura no rendimento de cada estrutura. A significância de cada variável foi determinada através de planejamentos experimentais, cujas variáveis resposta foram as áreas de picos de difração de raios X específicos. O CTAB não agiu como direcionador estrutural, mas sim como modificador de crescimento, aumentando a taxa de crescimento dos cristais. Em temperatura baixa, LTA foi obtida em baixas razões Si/Al, enquanto FAU cristalizou-se em razões maiores, indicando uma competição entre as duas estruturas. O aumento da temperatura aumentou a cinética de recristalização das fases LTA e FAU, menos densas e metaestáveis, em fases mais densas e mais estáveis, como sodalita e cancrinita. A diminuição de concentração de Na+ e água reduziu a cristalinidade das estruturas, enquanto que o aumento de Na+ favoreceu a formação de FAU em detrimento de LTA.

Abstract LTA and FAU zeolites were synthesized with the addition of cetyltrimethylammonium bromide (CTAB) to assess the effects of Si/Al, Na/Al and H2O/Al ratios, time and temperature on the yield of each structure. The significance of each variable was determined by means of experimental designs, whose response variables were the areas of specific XRD peaks. CTAB did not act as a structure-directing agent, but rather as a growth modifier, increasing the growth rate of LTA and FAU crystals. At low temperature, LTA was afforded at low Si/Al ratio, while FAU crystallized at higher ratios, indicating a competition between the phases. Increasing temperature accelerated the kinetics of recrystallization of the less dense and metastable LTA and FAU phases in denser and more stable phases, such as sodalite and cancrinite. Decreasing the concentration of Na+ and water reduced the crystallinity of both structures, while increasing the concentration of Na+ favored LTA over FAU.

Cryptococcosis is a systemic mycosis usually affecting immunodeficient individuals. In contrast, immunologically competent patients are rarely affected. Dissemination of cryptococcosis usually involves the central nervous system, manifesting as meningitis or meningoencephalitis. Prostatic lesions are not commonly found. A case of prostate cryptococcal infection is presented and cases of prostatic cryptococcosis in normal and immunocompromised hosts are reviewed. A fifty-year-old HIV-negative man with urinary retention and renal insufficiency underwent prostatectomy due to massive enlargement of the organ. Prostate histopathologic examination revealed encapsulated yeast-like structures. After 30 days, the patient's clinical manifestations worsened, with headache, neck stiffness, bradypsychia, vomiting and fever. Direct microscopy of the patient's urine with China ink preparations showed capsulated yeasts, and positive culture yielded Cryptococcus neoformans. This fungus was later isolated from cerebrospinal fluid and blood cultures, demonstrating thus its dissemination. The patient was discharged after 27 days in hospital and, despite a regimen of amphotericin B, he died four months later. This case points to cryptococcosis as a possible cause of prostatic disease and reinforces the importance of communication between the medical team and pathology and microbiology laboratories aiming at a more accurate diagnosis and successful treatment.

To improve the performance of critical part components, new methods for surface strengthening are being developed with success, like plasma immersion ion implantation (PIII) and hybrid surface treatments mixing PIII and ion nitriding processes. A combination of high pressure (4 × 10¹Pa), moderate temperature (up to 450ºC) glow discharge nitriding with low pressure (8 × 10-2Pa) and low DC bias voltage ion nitriding (or DC PIII) was implemented. Depending on the particular conditions of the treatment and the depth probed, mixed phases of gammaN and epsilon were measured in the treated SS304 steel sample. This near surface modification resulted in an improved hardness (up to a factor of 2.7 ×) of the sample which could also enhance its wear properties. Surface modification of Ti6Al4V alloy and SS304 steel by a combination of PIII and subsequent ion nitriding was investigated as well. Nitrogen ions were implanted into the specimens at 15 keV and then ion nitrided at low pressure (7 × 10-2Pa) with a bias of -800 V. Compared to the untreated samples, the hardness of Ti6Al4V alloy and the steels could be improved significantly. AES results indicated high retained doses in both samples, confirming the high efficiency of this hybrid process.

Foi utilizado novo dispositivo para amostragem de macroinvertebrados bênticos de água doce num segmento do curso inferior arenoso de um rio brasileiro subtropical (Rio Caí, Triunfo, RS) e de seu pequeno tributário, Arroio Bom Jardim. Neste estudo, a efetividade do amostrador PET foi testada em locais diferentes do rio e do arroio e ao longo das quatro estações do ano, entre 2001-2002. Foram realizadas comparações por PCA e ANOVA, ambos empregando um procedimento "bootstrap" com base em matrizes de similaridade. O amostrador PET é confiável para detecção de diferenças sazonais e espaciais de riqueza, abundância total de organismos e diversidade de Shannon no rio e no arroio, sendo, portanto, recomendável para o monitoramento de comunidades de macroinvertebrados nesse sistema.

A new device to sample freshwater benthic macroinvertebrates was used in a low and sandy stretch of a Brazilian sub-tropical river (the River Caí, Triunfo, RS) and in one of its small tributaries, Bom Jardim brook (Arroio Bom Jardim). In this study, the effectiveness of this device, a PET sampler, was tested at different sites in the river and the brook throughout the four seasons between 2001-2002. Comparisons were made by PCA and ANOVA, both employing a bootstrap procedure based on similarity matrices. The PET sampler proved to be a reliable tool for detection of seasonal and spatial differences in richness, total abundance of organisms, and Shannon's diversity index in both river and brook and is therefore recommended for use in the monitoring of macroinvertebrate communities in this system.