6 resultados para stems
em Universidade do Minho
Resumo:
The aim of this study was to characterize sweet cherry regarding nutritional composition of the fruits, and individual phytochemicals and bioactive properties of fruits and stems. The chromatographic profiles in sugars, organic acids, fatty acids, tocopherols and phenolic compounds were established. All the preparations (extracts, infusions and decoctions) obtained using stems revealed higher antioxidant potential than the fruits extract, which is certainly related with its higher phenolic compounds (phenolic acids and flavonoids) concentration. The fruits extract was the only one showing antitumor potential, revealing selectivity against HCT-15 (colon carcinoma) (GI50~74 μg/mL). This could be related with anthocyanins that were only found in fruits and not in stems. None of the preparations have shown hepatotoxicity against normal primary cells. Overall, this study reports innovative results regarding chemical and bioactive properties of sweet cherry stems, and confirmed the nutritional and antioxidant characteristics of their fruits.
Resumo:
Tese de Doutoramento em Ciências da Educação (área de especialização em Tecnologia Educativa)
Resumo:
The employ of vegetal fibers for textiles and composites represents a great potential in economic and social sustainable development. Some Malvaceae species are considered tropical cosmopolitans, such as from Sida genus. Several species of this genus provide excellent textile bast fibers, which are very similar in qualities to the jute textile fiber. The objective of the present study is present the physicochemical characterization of six Brazilian vegetal fibers: Sida rhombifolia L.; Sida carpinifolia L. f.; Sidastrum paniculatum (L.) Fryxell; Sida cordifolia L.; Malvastrum coromandelianum (L.) Gurck; Wissadula subpeltata (Kuntze) R.E.Fries. Respectively the two first species are from Brazilian Atlantic Forest biome and the four remaining from Brazilian Cerrado biome, despite of present in other regions of the planet. The stems of these species were retted in water at 37oC for 20 days. The fibers were tested in order to determine tensile rupture strength, tenacity, elongation, Young’s modulus, cross microscopic structure, Scanning Electronic Microscopy (SEM), regain, combustion, acid, alkali, organic solvent and cellulase effects, pH of the aqueous extract, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The obtained values were compared with those from fibers of recognized applicability in the textile industry including hemp. The results are promising in terms of their employment in thermoset and thermoplastic medium resistance composites.
Resumo:
Tese de Doutoramento em Biologia de Plantas
Resumo:
Tese de Doutoramento (Programa Doutoral em Engenharia Biomédica)
Resumo:
O texto que propomos parte de uma pesquisa longitudinal, realizada em Portugal entre 2008 e 2010, com professores do 1º Ciclo do Ensino Básico. Procura evidenciar os conflitos e incertezas que a avaliação do desempenho docente tem produzido e a busca de sentido(s) para esta avaliação e para o ‘ser professor/a’. A implementação de sistemas de avaliação do desempenho dos professores insere-se na procura de soluções para esta inquietação. Foi o que aconteceu em Portugal, em Janeiro de 2007, com a publicação em Diário da República do novo Estatuto da Carreira Docente e o Decreto que regulamentava a Avaliação do Desempenho Docente. As tensões emergiram entre docentes e Ministério da Educação, agudizaram-se com a tomada de consciência da problemática da avaliação do desempenho dos docentes com impacto na carreira profissional e provocaram incertezas e desmotivação face ao sentido do trabalho docente com impacto na identidade profissional dos professores.