Luiza Silva

The objective of this study was to develop and validate a fast, sensitive and simple liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the screening of six classes of antibiotics (aminoglycosides, beta-lactams, macrolides, quinolones, sulfonamides and tetracyclines) in fish. Samples were extracted with trichloroacetic acid. LC separation was achieved on a Zorbax Eclipse XDB C18 column and gradient elution using 0.1% heptafluorobutyric acid in water and acetonitrile as mobile phase. Analysis was carried out in multiple reaction monitoring mode via electrospray interface operated in the positive ionization mode, with sulfaphenazole as internal standard. The method was suitable for routine screening purposes of 40 antibiotics, according to EC Guidelines for the Validation of Screening Methods for Residues of Veterinary Medicines, taking into consideration threshold value, cut-off factor, detection capability, limit of detection, sensitivity and specificity. Real fish samples (n=193) from aquaculture were analyzed and 15% were positive for enrofloxacin (quinolone), one of them at a higher concentration than the level of interest (50µgkg(-1)), suggesting possible contamination or illegal use of that antibiotic.

Este trabalho analisa relatos de vida e de formação de professores concluintes de uma licenciatura em Matemática ofertada a distância, por uma instituição de natureza público-privada, no Tocantins. Os dados foram gerados em entrevistas realizadas ao longo de 2012 com cinco professores recém-formados, que encontraram no curso a distância a possibilidade de conciliação entre educação e exercício profissional. Na geração dos dados, mobilizamos orientações trazidas pela metodologia da história oral, que parte da perspectiva de que as histórias singulares e particulares dialogam expressamente com a história coletiva e plural e, desse modo, os relatos de experiência desses docentes poderiam contribuir para a compreensão de questões mais amplamente vividas na educação no contexto das práticas do Norte do país. Para análise das narrativas, utilizamos fundamentos da semiótica discursiva, mais especificamente relacionados ao que essa teoria denomina como sintaxe do nível narrativo. Pelas reit...

The (liquid+liquid) equilibrium (LLE) data for two systems containing heptane, toluene, and 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide ([mpim][Tf2N]) or 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([amim][Tf2N]) ionic liquids (ILs) were determined at T=313.2K and atmospheric pressure. The effect of a double bond in an alkyl side chain in the imidazolium cation was evaluated in terms of selectivity and extractive capacity. The results show a decrease of the