We report here preliminary studies of biocidal effects and cellular internalization of ZnO nanoparticles on Escherichia coli bacteria. ZnO nanoparticles were synthesized in di(ethylene glycol) (DEG) ...medium by forced hydrolysis of ionic Zn super(2+) salts. Particle size and shape were controlled by addition of small molecules and macromolecules such as tri-n-octylphosphine oxide, sodium dodecyl sulfate, polyoxyethylene stearyl ether, and bovine serum albumin. Transmission electron microscopy (TEM) and X-ray diffraction analyses were used to characterize particle structure, size, and morphology. Bactericidal tests were performed in Luria-Bertani medium on solid agar plates and in liquid systems with different concentrations of small and macromolecules and also with ZnO nanoparticles. TEM analyses of bacteria thin sections were used to study biocidal action of ZnO materials. The results confirmed that E. coli cells after contact with OEG and ZnO were damaged showing a Gram-negative triple membrane disorganization. This behavior causes the mcrease of membrane permeability leading to accumulation of ZnO nanoparticles in the bacterial membrane and also cellular internalization of these nanoparticles.
Niobia, zirconia, ceria–niobia and ceria–zirconia oxide nanoparticles are prepared by soft chemical routes and show valuable textural properties. The pore volume and specific surface area keep ...significant values even after calcination at 873
K. According to DRX and STEM-EDX measurements, solid solutions are obtained in the case of ceria–zirconia, whereas separate phases are identified in ceria–niobia; in the latter case, however, UV–Vis diffuse reflectance spectroscopy shows also the formation of defects (color centers) arising from a partial dissolution at the interface of the oxide phases.
O conceito de espaço socialmente organizado, subsidiado por novas técnicas de análise, mapeamento e espacialização da ocorrência de eventos, tem orientado desenvolvimentos metodológicos inovadores no ...campo das intervenções de saúde pública. Este estudo teve por objetivo avaliar a utilização de um indicador sócio-ambiental, construído através da metodologia de aplicação de escores, na estratificação do Município de Olinda, Pernambuco, em áreas com diferentes riscos de transmissão da filariose bancroftiana. Procedeu-se ao mapeamento das áreas, localização dos domicílios amostrados e identificação de todos os moradores com idade entre 5 e 65 anos para realização do inquérito parasitológico. Dentre as 3.232 pessoas examinadas, 42 foram positivas, obtendo-se prevalência de microfilaremia de 1,3%. A análise estatística global da distribuição dos casos mostrou evidências de agregação espacial. Nos dois estratos de mais alto risco de transmissão residiam 85,7% dos positivos. A alta sensibilidade do indicador proposto justifica a sua utilização para o planejamento e execução de intervenções ao predizer o local de ocorrência da maioria dos casos de filariose.
The concept of a "socially organized space" supported by new analytical techniques and mapping of health events has guided innovative methodological developments in public health interventions. This ...study aimed to evaluate a social/environmental indicator constructed with a scoring methodology to stratify areas in the city of Olinda by different levels of risk for Bancroftian filariasis transmission. The study mapped areas and the location of sample households and identified all residents ages 5 to 65 years as part of the parasitological survey. Among the 3,232 individuals who had blood samples taken, 42 were microfilaremic (1.3% prevalence). Global statistical analysis of filarial case distribution has suggested spatial clustering. Some 85.7% of positive individuals resided in the two strata with the highest transmission risk. The high sensitivity of the proposed indicator for predicting the places where the vast majority of filariasis cases occurred justifies its use in planning and implementing interventions.
This paper presents a context-aware tool for remote database administration that is executed in mobile devices, MDBA (mobile database administrator). The MDBA enables database administrators (DBAs) ...to perform their tasks by automatically identifying databases and the wireless communication structure of a given mobile computational environment. The proposed tool has properties, which integrate features of mobile computation pervasive computation paradigms and introduces also the notion of remote database administration, which is supported by a new computational paradigm, denoted ubiquitous computation. Therefore, the MDBA tool provides database administration services anywhere and anytime. Furthermore, the MDBA enables DBAs to manage databases residing in mobile hosts or fixed hosts.
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