938 resultados para Biogeochemistry|Analytical chemistry|Environmental science


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A sample preparation method based on ultrasound assisted-extraction (UAE) of Ca, Mg and P from swine feed has been described. The experiment was performed to cover the variables influencing the sonication process and, the method validation using standard reference material. Final solutions obtained upon sonication were analyzed by flame atomic absorption spectrometry (for Ca and Mg) and by UV-vis spectrophotometry (for P). The best conditions for metal extraction were as follows: sample mass: 100 mg in 20 mL 0.10 mol/L HCl, a particle size: <60 μm, sonication time: 5 cycles of 10 s and ultrasound power: 102 W. The UAE method was applied in digestibility assays in different piglet feeds and their results showed that it is highly comparable (P > 0.05) to the other methods used for such purposes, as block digestion, and offered a Ca, Mg and P method of quantification limit of 10.6, 12.4 and 14 mg/kg, respectively. The major advantages of the UAE method compared to other methods are the high treatment rate, low reagent usage in the extracts and, it does not generate toxic residues that might negatively affect human health and the environment, accompanied by good precision and accuracy.

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Fusidic acid, an antibiotic produced from the Fusidium coccineum fungus, belongs to the class of steroids, but has no corticosteroid effects. It is indicated for the treatment of infections caused by methicillin-resistant Staphylococcus aureus strains. The aim of this study was to search for the properties of fusidic acid published so far in the literature, as well as the methods developed for its determination in biological samples and pharmaceutical formulations. From the findings, we can conclude that fusidic acid has been used for decades and is indicated for the treatment of serious infections caused by Gram-positive microorganisms to this day. Furthermore, it is a hypoallergenic agent, has low toxicity, shows low resistance, and has no cross-resistance with other clinically used antibiotics. The analytical method of high-performance liquid chromatography has been widely used, since it can reduce the cost and time of analysis, making it more viable for routine quality control in the pharmaceutical industry.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Antimicrobials have unquestionable importance in the control of many diseases; however the constant concern with evolution of resistant microorganisms is increasing. The ertapenem sodium is a β-lactam antibiotic of the carbapenem class, which it has a broader activity spectrum than most other β-lactam antimicrobials, and is more resistant to the enzyme β-lactamase, which is the main mechanism of resistance of many bacteria. The progress of microbial resistance to existing antibiotics is alarming. Thus we need to preserve antimicrobials that still have activity against these pathogens. In this context, the quality control has a key role to ensure the correct dosage, by contributing preventively to minimize the development of resistant microorganisms. Study of the physicochemical characteristics of the drug and the quantification of the content of active substance are of fundamental importance for the pharmaceutical industry to ensure the quality of the product sold. This work presents a literature survey of existing methods for ertapenem sodium quantification which was performed. Ertapenem sodium can be analyzed by many types of assays; however the HPLC is the most used method. This review will examine the published analytical methods reported for determination of ertapenem sodium, in biological fluids and formulations.

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Twenty six bottom sediment samples were collected from the Cananeia estuary in summer and winter of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis. Total mercury was determined by cold vapor atomic absorption. As, Cr, Hg and Zn concentrations were compared to the Canadian oriented values (TEL and PEL). Sample points 4 and 9 presented higher concentration for most elements and As and Cr exceeded the TEL values. Organic matter (>10%) associated with siltic and clay sediments was observed. Climatic conditions, hydrodynamic and biogeochemical processes promote differences in seasonal concentrations of elements at some points, which contribute to special distributions.