842 research outputs found

    Mathematical model of brain tumour with glia-neuron interactions and chemotherapy treatment

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    Acknowledgements This study was possible by partial financial support from the following Brazilian government agencies: Fundação Araucåria, EPSRC-EP/I032606/1 and CNPq, CAPES and Science Without Borders Program Process nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPreprin

    Effect of the KMnO4 treatment on the "pinhĂŁo" starch.

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    O pinhĂŁo, sementes de Araucaria angustifolia, tem o amido como componente principal. Os amidos oxidados melhoram as caracterĂ­sticas fĂ­sico-quĂ­mica, de pasta e tĂ©rmicas dos produtos em processos industriais. O amido de pinhĂŁo nativo foi tratado com soluçÔes padronizadas de permanganato de potĂĄssio (KMnO4) e as amostras foram analisadas por tĂ©cnicas termoanalĂ­ticas (TG-DTA) em atmosfera inerte. As amostras foram oxidadas da seguinte forma: quatro porçÔes de 20 g (base seca) foram separadas e trĂȘs foram suspensas em solução de KMnO4 (0,001; 0,002; 0,005 mol L-1) em agitação constante durante 30 minutos, a quarta amostra foi mantida como recebida. As suspensĂ”es de amido foram filtradas, lavadas, secas e analisadas. As modificaçÔes oxidativas provocaram mudanças estruturais das molĂ©culas de amido, registradas pelos diferentes resultados calculados a partir das curvas TGA e DTA. A amostra (3) teve as mudanças mais significativas na degradação com o 3ÂȘ evento exotĂ©rmico com temperaturas acima de 330 °C

    Relação de Meloidogyne arenaria com o desenvolvimento radicular do porta-enxerto SO4. de videira

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    O objetivo deste trabalho foi avaliar a relação entre a presença de Meloidogyne arenaria no solo e o desenvolvimento radicular do porta-enxerto SO4 de videira. Foram avaliados, alĂ©m deste porta-enxerto, o ?Harmony? e o ?IAC 766? por serem amplamente utilizados na vitivinicultura do SubmĂ©dio do Vale do SĂŁo Francisco. O enraizamento foi feito em solo autoclavado contido em sacos para formação de mudas. ApĂłs 40 dias, as mudas foram transplantadas para vasos com capacidade de 20 L, conforme os seguintes tratamentos: 1) solo natural -- infestado com M. arenaria -- 2) solo autoclavado e com inoculação das mudas e 3) solo autoclavado e sem inoculação das mudas com M. arenaria. ApĂłs 6 meses, nenhuma anormalidade foi observada, visualmente, no sistema radicular dos porta-enxertos avaliados. Observou-se que o nematoide nĂŁo se multiplicou de forma diferenciada nos trĂȘs porta-enxertos, mas que o porta-enxerto ?Harmony? pode vir a se tornar uma opção de substituição do ?SO4? por se apresentar com tendĂȘncias a maior vigor do sistema radicular, visto nĂŁo ter ocorrido diferença significativa no nĂșmero de ovos quantificados nos trĂȘs porta-enxertos

    Evaluation of double treated starches using thermal tools.

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    Starch is the main polysaccharide found in cereals, composed by amylose and amylopectin. Corn is the principal source of starches worldwide. Starches treatment, through physical, chemical and/or biological methods, can improve the applications range. Acid modification in alcoholic solution promotes minimally degradation in the granule. Ball mill is one physical method poorly explored. The aim was to treat the starches using HCl 0.5 mol L-1 for 1 hour in 100 ml of aqueous, ethanol or methanol solutions with subsequent ball milling processes. One sample was selected as native sample. The four others, one native sample and three acid modified samples, were treated by physical process with the oscillating ball mill. The DTG-60H equipment was used for the TG and DTA analysis. The TG curves showed three mass losses related to dehydration, decomposition and oxidation. The native sample without physical modification showed major resistance to total degradation. This occurs because the physical modification cleaves hydrogen bonds, leaving a weakened granule. The TGDTA results showed that the mass loss in the 2nd event was minor in the hydrolyzed samples compared with native samples. The acid modification can provide starch higher resistance to degradation up to 340 °C. These results showed that chemical and physical treatment changed the thermal behaviors of the starches

    Evaluation of antifungal activity of essential oils against potentially mycotoxigenic Aspergillus flavus and Aspergillus parasiticus

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    The antifungal activity of essential oils of fennel (Foeniculum vulgare Mill., Apiaceae), ginger (Zingiber officinale Roscoe, Zingiberaceae), mint (Mentha piperita L., Lamiaceae) and thyme (Thymus vulgaris L., Lamiaceae) was evaluated against mycotoxin producers Aspergillus flavus and A. parasiticus. High Resolution Gas Chromatography was applied to analyze chemical constituents of essential oils. The effect of different concentrations of essential oils was determined by solid medium diffusion assay. Mycelial growth and sporulation were determined for each essential oil at the concentrations established by solid medium diffusion assay. At the fifth, seventh and ninth days the mycelial diameter (Ø mm) and spore production were also determined. FUN-1 staining was performed to assess cell viability after broth macrodilution assay. Trans-anethole, zingiberene, menthol and thymol are the major component of essential oils of fennel, ginger, mint and thyme, respectively. The effective concentrations for fennel, ginger, mint and thyme were 50, 80, 50 and 50% (oil/DMSO; v/v), respectively. The four essential oils analysed in this study showed antifungal effect. Additionally, FUN-1 staining showed to be a suitable method to evaluate cell viability of potential mycotoxigenic fungi A. flavus and A. parasiticus after treatment with essential oils.The authors are grateful to the colleagues from Laboratory of EPAMIG and Microbiology DEB/UFLA and the Micoteca da Universidade do Minho, Center for Biological Engineering, UMINHO for their support to perform this work. A special aknowledgment is also due to the FAPEMIG and MUM-UMINHO for the financial support of bench work and to CAPES for granting the first author with a PhD scholarship

    Relação custo-benefício de alguns produtos låcteos comparados com alimentos da cesta båsica de Juiz de Fora.

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