3,614 research outputs found

    Avaliação química e biológica da proteína do grão em cultivares de milho de alta qualidade protéica.

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    Cultivares de milho de alta qualidade protéica (QPM) desenvolvidos pela Embrapa Milho e Sorgo foram avaliados quanto ao conteúdo de aminoácidos essenciais e aproveitamento biológico da proteína, em ratos Wistar machos, recém-desmamados. Sete grupos de seis animais foram mantidos durante dez dias sob condições ambientais padronizadas, recebendo cada grupo uma das seguintes rações: a) controle a 10% e a 7% de proteína (caseína), b) aprotéica, c) experimentais com milho a 7% de proteína (QPM amarelo - BR 473, QPM branco - BR 451 e milho comum - BR 136), d) mistura arroz-feijão a 10% de proteína (1:1 em base protéica). A qualidade protéica do milho BR 473 foi semelhante à do milho BR 451 e significativamente superior (p<O,05) à do milho BR 136, segundo os índices NPR (Net Protein Ratio- 3,37; 3,54 e 2,58, respectivamente para BR 473, BR 451 e BR 136) e NPU (Net Protein Utilization - 56%,58% e 43%, respectivamente). Os milhos QPM possuem valor protéico elevado (média de 83% em relação à proteína de referência), similar ao da mistura arroz-feijão, constituindo-se em alimentos promissores para uso em programas de combate à desnutrição no Brasil, em especial para crianças de baixa renda

    Vertical accretion rates of mangroves in northeast Brazil:Implications for future responses and management

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    Northeast (NE) Brazil has a semi-arid climate and low plant diversity mangroves confined to estuaries influenced by a meso-tidal regime (∼2.5 m). Whilst these mangroves are protected by state and federal legislation, large areas have been lost to urban encroachment and shrimp farms, a situation continuing today. This work discusses the potential impacts of sea level rise on mangroves in three estuaries in NE Brazil. The three sites witness decreasing annual precipitation associated with global climate change, which will have the dual effect of increasing water and salinity stress, decreasing productivity, as well as reducing inputs of allochthonous fluvial material. Simultaneously, since the 1990's local sea level rise (3.5 mm/yr) has been greater than the global average (3.2 mm/yr). Average accretion rates, derived from 137Cs and 210Pb dating in fringing mangroves in this study, are likely to be insufficient to maintain surface elevation and keep pace with sea level rise. Notwithstanding, historical data suggest that there has been no recorded mangrove loss as a result of sea level rise and in some areas a recorded gain in the upper estuarine mangrove reaches. At present there are limited inputs from the watershed in all three estuaries, mostly due to decreasing annual rainfall and river damming, limiting the transport capacity and hampering the export of sediments to the fringing mangroves and the sea and limiting the ability of the fringing mangroves to respond to sea level rise. However, this has been suggested to result in the accumulation of soils along river margins further upstream forming new islands and potentially expanding estuarine mangroves upstream. Both the fringing and the estuarine mangroves are surrounded by both licensed and unlicensed settlements, as well as dunes preventing expansion into higher elevation areas as a response to sea level rise. Recent changes to legislation protecting these ecosystems put a further strain on adaptation and resilience capacity, increasing the threat to these important coastal systems and the ecosystem services they provide

    Evaluación de reservas corporales de grasa de vacas lecheras a través de un sistema de análisis de imagen

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    publishedTomo I . Sección: Sistemas Ganaderos-Economía y Gestión. Sesión: Producción de leche. Ponencia nº 3

    Relación entre la condición corporal y medidas de grasa y de músculo obtenidas por ultrasonografía en tiempo real con vacas de raza Barrosã

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    publishedTomo I . Sección: Sistemas Ganaderos-Economía y Gestión. Sesión: Vacuno carne II. Ponencia nº 1

    Poloxamer 407 based-nanoparticles for controlled release of methotrexate

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    Poloxamer 407 (P407)-based nanoparticles were produced by the high pressure homogenization method for the encapsulation and delivery of methotrexate (MTX), aiming intravenous therapeutic applications. The surface of these nanoparticles was functionalized by conjugation of P407 with folic acid (FA) or with MTX, which served as targeting ligand agents. MTX-P407 conjugate was also developed to increase the final drug cargo. Two hydrophobic derivatives of MTX, MTX di-ethylated ester (MTX-OEt) and the ionic complex MTX-dimethyldioctadecylammonium bromide (MTX-DODAB) were produced and entrapped onto P407-based nanoparticles. All formulations developed revealed a monodisperse character comprising small and narrow nanoparticles (<100 nm). P407 nanoparticles (functionalized with FA) and MTX-P407 nanoparticles, both loaded with MTX-OEt, demonstrated a slow drug release profile. The effect of lipase from Aspergillus oryzae on the hydrolysis of the linkage between the P407 and MTX, and consequent MTX release profile, was also evaluated. We observed a controlled and slow release of MTX (<50% of release after 11 days) in the presence of enzyme. These MTX-P407 nanoparticles loaded with MTX-OEt induced a great effect against Caco-2 cancer cells (40% of cell death after 72 h of incubation), demonstrating higher efficiency than the free MTX at the same concentration.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors also thanks to FCT for funding their scholarship: Jennifer Noro (SFRH/BD/121673/2016) and Carla Silva (SFRH/IF/00186/2015). This work has also received funding from the European Union Horizon 2020 research and innovation program under grant agreement NMP-06-2015-683356 FOLSMART.info:eu-repo/semantics/publishedVersio

    Una revisión de los discos de Fortios

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    We have used EDXRF, Micro-PIXE and optical microscopy (metallographic analysis), complemented with SEM-EDS, to first determine the elemental content, and second, to identify the process used to join the components (disk, peripheral rod and tab) of several Iron Age gold buttons. These have a very similar typology and were found at three archaeological sites in the South-Western part of the Iberian Peninsula. A set of 35 buttons from Castro dos Ratinhos (7), Outeiro da Cabeça (23) and Fortios (5) were analyzed and the results published in Trabajos de Prehistoria (Soares et al. 2010). Recently Perea et al. (2016) have published analyses of other 4 gold buttons from Fortios with the same purpose, but only using one technique, SEM-EDS. As they only analysed the rough surface layer, the results are neither effective nor reliable, taking into account the constraints associated with the technique, namely the small depth reached (< 2 ?m) by the incident beam and, consequently, its sensitivity to the topography of the analyzed surface. Despite these constraints, they have accepted uncritically their results and, at the same time, question our own analyses and results and the interpretation we have made. Here we discuss the approach of Perea et al. in order to determine not only the elemental content of the Fortios gold buttons, but also to identify the joining process used in their manufacture.Hemos empleado fluorescencia de rayos X por energía dispersiva (EDXRF), emisión de rayos X inducida por partículas (Micro-PIXE) y microscopía (análisis metalográfico), complementada con microscopia electrónica de barrido y espectroscopia de rayos X en energía dispersiva (SEM-EDS), primero para determinar el contenido elemental y segundo para identificar el proceso empleado para unir los componentes (disco, anillo periférico y presilla) de varios de los discos de oro de la Edad del Hierro. Su tipología es muy similar y fueron encontrados en tres yacimientos arqueológicos de la zona suroccidental de la Península Ibérica. Una serie de 35 discos del Castro dos Ratinhos (7), Outeiro da Cabeça (23) y Fortios (5) fueron analizados y sus resultados publicados en Trabajos de Prehistoria (Soares et al. 2010). Recientemente Perea et al. (2016) han publicado análisis de otros 4 discos de oro de Fortios con el mismo propósito pero usando solo SEM-EDS. Al haber analizado solo la capa superficial irregular, los resultados no son reales, ni fiables, considerando las limitaciones asociadas con la técnica, especialmente la escasa profundidad alcanzada (< 2 ?m) por el haz incidente y, consecuentemente, su sensibilidad a la topografía de la superficie analizada. A pesar de esas limitaciones, han aceptado acríticamente sus resultados y, a la vez, han puesto en cuestión nuestros análisis y resultados y las interpretaciones que hemos hecho. Aquí discutimos el enfoque de Perea et al. para determinar no solo el contenido elemental de los discos de oro de Fortios, sino también para identificar el proceso de unión empleado en su manufactura

    Estudio de botones de oro de la primera Edad del Hierro del Sudoeste de la Península Ibérica. Identificación de un taller metalúrgico de oro

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    Early Iron Age gold buttons from Castro dos Ratinhos, Fortios and Outeiro da Cabeça were analysed by conventional EDXRF, Micro-PIXE, SEM-EDS and Optical Microscopy. EDXRF results point out to a rather homogeneous alloy composition throughout all the analysed buttons. PIXE microanalyses show that all the button components (disk, tab and peripheral grooved decorated rod) have the same alloy composition. PIXE and SEM-EDS microanalyses, supplemented with optical microscopy characterization, show the absence of chemical composition differences between distinct components and joining zones, suggesting that no solder had been applied, i.e. that a partial melting/solid state diffusion process had been used for the welding of button components. Finally, the noticeable similar compositions together with the use of the same welding process and the very similar artefact typologies suggest that those small gold treasures could be interpreted as the result of the work of a single metallurgical workshop, probably located somewhere in the South-Western Iberian Peninsula.Botones de oro pertenecientes a la primera Edad del Hierro, procedentes de Castro dos Ratinhos, Fortios e Outeiro da Cabeça (Portugal), fueron analizados por EDXRF y Micro-PIXE. Los resultados de los análisis por EDXRF mostraron una composición similar en todos los botones, independientemente de su procedencia. Por otra parte, los microanálisis por PIXE permitieron verificar que los componentes soldados de cada botón (disco, presilla y cordón exterior) tienen la misma composición química. Además de eso, las áreas de soldadura fueron estudiadas mediante Micro-PIXE, SEM-EDS y posterior análisis metalográfico por microscopia óptica de reflexión. Estos análisis permitieron comprobar la ausencia de soldaduras en las zonas de unión de estos componentes, lo que nos permite concluir que debe haber tenido lugar un proceso de fusión parcial y de difusión en estado sólido para unir los componentes de estos botones. La gran semejanza en la composición química, junto a la presencia del mismo tipo de soldadura y tipologías similares, nos sugiere que todas estas piezas fueron resultado del trabajo de un mismo artesano-joyero, cuyo taller se encontraría localizado en el sudoeste de la Península Ibérica

    Extraction and characterization of polysaccharides from non-traditional Brazilian Amazon sources

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    [Excerpt] Cupuassu (Theobroma grandiflorum), tucumã (Astrocaryum aculeatum), peach palm (Bactris gasipaes) and abricó (American Mammea L.) are exotic fruits found in the Brazilian Amazon rainforest. All of them are well known by the native populations, and for centuries the pulps have been used in the production of juices, deserts, jams, syrups, and alcoholic beverages, among others. Additionally, the fruit seeds have been used as animal feed, fertilizers or to plant new seedlings, but a great part of these seeds are usually discarded. (...
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