483 research outputs found

    Molecular model of TriBP1, a protein involved in nuclear import.

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    Further structural analysis will be performed in order to understand the biological properties and roles of TriBP1 and TriBP2.X-meeting 2007

    Development and performance analysis of a metallic passive micro-direct methanol fuel cell for portable applications

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    Due to the growing interest on miniaturization for application on portable devices, the Micro Direct Methanol Fuel Cells (Micro-DMFC) proved to have great benefits. Passive fuel cells have extra advantages leading to less complex and cheaper systems. In the present work, an experimental study on the performance of a passive Micro-DMFC with an active area of 2.25 cm2 working at ambient conditions is described. Several commercially available materials for Membrane Electrode Assembly (MEA) are tested including materials with low platinum content to achieve lower prices. The effect of methanol concentration on the cell performance is evaluated. The performance is compared with the one obtained using an active Micro-DMFC with the same active area. A optimized design is proposed corresponding to a maximum power density, 19.2 mW/cm2, obtained using a Nafion 117 membrane, 3 mg/cm2 Pt–Ru and 0.5 mg/cm2 Pt as, respectively, anode and cathode catalyst loading, carbon paper as anode gas diffusion layer (GDL) and Sigracet carbon paper with micro porous layer (MPL) as cathode GDL at methanol feed concentration of 3 M. This result higher than the optimal power obtained with the active Micro-DMFC clearly demonstrates that membranes with low catalyst content could be used in passive MicroDMFC with success. This is an important result bearing in mind the use of micro-DMFCs in portable applications

    An indirect evidence of the Fibonacci String model for DNA repetitive sequence growth.

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    In this work, we present some results that are indirect evidences of Fibonacci String model fro DNA repetitive sequences growth.X-Meeting 2007

    Motion-resolved fat-fraction mapping with whole-heart free-running multiecho GRE and pilot tone.

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    To develop a free-running 3D radial whole-heart multiecho gradient echo (ME-GRE) framework for cardiac- and respiratory-motion-resolved fat fraction (FF) quantification. (N <sub>TE</sub> = 8) readouts optimized for water-fat separation and quantification were integrated within a continuous non-electrocardiogram-triggered free-breathing 3D radial GRE acquisition. Motion resolution was achieved with pilot tone (PT) navigation, and the extracted cardiac and respiratory signals were compared to those obtained with self-gating (SG). After extra-dimensional golden-angle radial sparse parallel-based image reconstruction, FF, R <sub>2</sub> *, and B <sub>0</sub> maps, as well as fat and water images were generated with a maximum-likelihood fitting algorithm. The framework was tested in a fat-water phantom and in 10 healthy volunteers at 1.5 T using N <sub>TE</sub> = 4 and N <sub>TE</sub> = 8 echoes. The separated images and maps were compared with a standard free-breathing electrocardiogram (ECG)-triggered acquisition. The method was validated in vivo, and physiological motion was resolved over all collected echoes. Across volunteers, PT provided respiratory and cardiac signals in agreement (r = 0.91 and r = 0.72) with SG of the first echo, and a higher correlation to the ECG (0.1% of missed triggers for PT vs. 5.9% for SG). The framework enabled pericardial fat imaging and quantification throughout the cardiac cycle, revealing a decrease in FF at end-systole by 11.4% ± 3.1% across volunteers (p < 0.0001). Motion-resolved end-diastolic 3D FF maps showed good correlation with ECG-triggered measurements (FF bias of -1.06%). A significant difference in free-running FF measured with N <sub>TE</sub> = 4 and N <sub>TE</sub> = 8 was found (p < 0.0001 in sub-cutaneous fat and p < 0.01 in pericardial fat). Free-running fat fraction mapping was validated at 1.5 T, enabling ME-GRE-based fat quantification with N <sub>TE</sub> = 8 echoes in 6:15 min

    Management oriented mathematical modelling of Ria Formosa (South Portugal)

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    1 - Ria Formosa is a large (c.a. 100 km2) mesotidal lagoon system included in a Natural Park, with large intertidal areas and several uses such as fisheries, aquaculture, tourism and nature conservation. Its watersheds cover an area of approximately 864 km2, with a hydrographic network of small and, mostly, ephemeral rivers. 2 - The Soil and Water Assessment Tool (SWAT model) has been applied to the catchments in order to simulate water discharges to Ria Formosa, providing forcing to a two-dimensional vertically integrated model, implemented with EcoDynamo – an object oriented modelling software – including hydrodynamics, water column, sediment biogeochemistry and growth models for some important benthic species. 3 - The main objectives of this work are to: (i) Analyse model performance in the light of available data; (ii) Evaluate the effects of dredging operations and changes in biomass densities of cultivated clams, on lagoon biogeochemistry and water quality. 4 - This work is part of a larger project where many possible management scenarios are being analysed following concerns expressed by the project end-users – Ria Formosa Natural Park authority. 5 - Results obtained so far suggest that bivalve rearing areas are probably being exploited close to their carrying capacity. Furthermore, it is apparent that some improvement on water quality could be achieved by reducing bivalve densities, without significant losses of harvest yields

    CĂĄlculo analĂ­tico de parĂąmetros estruturais de proteĂ­nas usando a teoria Alpha Shapes.

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    bitstream/CNPTIA/11660/1/bp17.pdfAcesso em 28 maio 2008

    Detecção de erros de montagens em regiĂ”es gĂȘnicas.

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    Muitos genomas ainda apresentam erros de montagem. Tais erros sĂŁo particularmente graves se ocorrerem em regiĂ”es gĂȘnicas, pois muitos trabalhos cientĂ­ficos se concentram exatamente nessas regiĂ”es por razĂ”es Ăłbvias. Uma forma de tentar identificar erros de montagens em regiĂ”es gĂȘnicas Ă© utilizar sequencias adquiras de forma independente, como, por exemplo bases de ESTs ou bases de Full length cDNA (FlcDNA). O foco deste trabalho Ă© propor uma metodologia de BioinformĂĄtica que utiliza bibliotecas de FlcDNA para detectar tais erros

    Avaliação genĂ©tica de progĂȘnies e indivĂ­duos de açaizeiro para nĂșmero de perfilhos e Ă­ndice de produtividade volumĂ©trica de palmito.

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    Este trabalho teve como objetivo a avaliação genotĂ­pica de progĂȘnies e indivĂ­duos de uma população de açaizeiro e estimação de parĂąmetros genĂ©ticos para os caracteres nĂșmero de perfilhos e Ă­ndice de produtividade volumĂ©trica de palmito nos perfilhos
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