170 research outputs found

    Key Success Factors and Future Perspective of Silicon-Based Solar Cells

    Get PDF
    Today, after more than 70 years of continued progress on silicon technology, about 85% of cumulative installed photovolatic (PV) modules are based on crystalline silicon (c-Si). PV devices based on silicon are the most common solar cells currently being produced, and it is mainly due to silicon technology that the PV has grown by 40% per year over the last decade. An additional step in the silicon solar cell development is ongoing, and it is related to a further efficiency improvement through defect control, device optimization, surface modification, and nanotechnology approaches. This paper attempts to briefly review the most important advances and current technologies used to produce crystalline silicon solar devices and in the meantime the most challenging and promising strategies acting to increase the efficiency to cost/ratio of silicon solar cells. Eventually, the impact and the potentiality of using a nanotechnology approach in a silicon-based solar cell are also described

    Mineral content, phenolic compounds and bioactive amines of cheese bread enriched with cowpea.

    Get PDF
    Cheese bread presents great acceptance and market expansion. Due to the lack of standardization in its manufacturing, various ingredients can be added. It was aimed to determine the content of minerals, bioactive compounds and antioxidant activity in cheese bread enriched with biofortified cowpea. Two formulations were prepared, standard cheese bread (without cowpea) and enriched cheese bread. The minerals were analyzed using the plasma emission spectrometry technique with inductive coupling, phenolic compounds and antioxidant activity were determined by spectrophotometry and the amines by High Performance Liquid Chromatography. All analyzes were performed in triplicate and for the comparison of the means between two variables, Student?s t-test was applied and for multiple comparisons, the Tukey test. It was observed that the enriched cheese bread is source of copper, zinc and sodium and presents high content of calcium, phosphorus and magnesium, considering the recommendations for the children?s audience. The concentrations of total phenolics, flavonoids and condensed tannins increased significantly with the introduction of cowpea. It was also observed an significant increase of spermidine, cadaverine and agmatine. The antioxidant activity was statistically higher in enriched cheese bread. It is concluded, therefore, that cheese bread with cowpea contributes to the supply of minerals and bioactive compounds

    PGC-1α induced browning promotes involution and inhibits lactation in mammary glands

    Get PDF
    The PPARγ coactivator 1α (PGC-1α) is a transcriptional regulator of mitochondrial biogenesis and oxidative metabolism. Recent studies have highlighted a fundamental role of PGC-1α in promoting breast cancer progression and metastasis, but the physiological role of this coactivator in the development of mammary glands is still unknown. First, we show that PGC-1α is highly expressed during puberty and involution, but nearly disappeared in pregnancy and lactation. Then, taking advantage of a newly generated transgenic mouse model with a stable and specific overexpression of PGC-1α in mammary glands, we demonstrate that the re-expression of this coactivator during the lactation stage leads to a precocious regression of the mammary glands. Thus, we propose that PGC-1α action is non-essential during pregnancy and lactation, whereas it is indispensable during involution. The rapid preadipocyte–adipocyte transition, together with an increased rate of apoptosis promotes a premature mammary glands involution that cause lactation defects and pup growth retardation. Overall, we provide new insights in the comprehension of female reproductive cycles and lactation deficiency, thus opening new roads for mothers that cannot breastfeed

    Características físico-químicas de farinhas de duas cultivares de feijão-caupi (Vigna unguiculata l. Walp): BRS Tumucumaque e BRS Aracê.

    Get PDF
    O feijão-caupi (Vigna unguiculata (L.) Walp.) é uma leguminosa amplamente cultivada no Brasil com valor nutritivo elevado quanto a proteínas, minerais e componentes bioativos e cultivares biofortificadas com melhoria do teor de nutrientes tem sido desenvolvidas pela Empresa Brasileira de Pesquisa Agropecuária, Embrapa. Há uma crescente utilização das farinhas mistas na composição de alimentos enriquecidos, sendo importante estudos de viabilidade de utilização de matérias-primas de elevado valor nutritivo, como o feijão-caupi, para elaboração destas farinhas. Tendo em vista essa necessidade, desenvolveu-se o presente trabalho com o objetivo de concretizar física e quimicamente farinhas de duas cultivares de feijão caupí biofortificados. As análises físicas e químicas das farinhas de ambas as cultivares foram realizadas em triplicata. As farinhas apresentaram de Índice de Solubilidade em Água superiores aos das referências consultadas, bom indicativo para produção de alimentos como sopa e mingaus. Quanto a composição centesimal, destacam-se os teores de proteínas e cinzas, como esperado devido a biofortificação e baixo teor de umidade que prediz estabilidade das farinhas. Ao analisar a concentração de minerais, as farinhas de feijão-caupi mostraram alto conteúdo de Fe, Zn, P, K e Mg. A cultivar BRS Tumucumaque apresentou teores de alguns minerais estatisticamente (p<0.05) superior em relação a cultivar BRS Aracê. Assim, as farinha de cultivares biofortificadas de feijão-caupi demonstraram possuir propriedades físicas, químicas e valor nutritivo favoráveis para o desenvolvimento de produtos alimentícios, devido a boa estabilidade, elevado teor de proteínas, alto conteúdo de minerais e ISA elevado.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/038b.pdf. Acesso em: 03 jul. 2013

    Composição centesimal e teor de minerais em pão de queijo enriquecido com farinha de feijão-caupi.

    Get PDF
    O feijão-caupi (Vigna unguiculata (L.) Walp) apresenta um importante papel na nutrição humana por constituir uma fonte de proteínas, carboidratos, fibras alimentares, vitaminas e minerais. A escolha do pão de queijo para o enriquecimento foi devido à importância dos produtos de panificação na lista de compra dos brasileiros, ocupando a terceira colocação e representando, em média, 12% do orçamento familiar para alimentação. Logo, objetivou-se o enriquecimento de pão de queijo, um produto que faz parte do consumo alimentar, com ascensão de mercado e utilizando-se matéria-prima regional. Determinou-se umidade, cinzas, proteínas, lipídios e carboidratos conforme AOAC (1995) e valor calórico pelos fatores de conversão de Atwater. A técnica de espectrometria de emissão atômica com fonte de plasma indutivamente acoplado (ICP OES) foi utilizada para a quantificação dos minerais. Utilizou-se o Programa EPI ? INFO, versão 6.04b para análise dos dados. Os resultados da composição centesimal e conteúdo de minerais foram analisados por ANOVA. Para verificar diferença entre as médias foi aplicado o teste de Tukey. O nível de significância foi de 5%. Como resultado, observou-se que o pão de queijo formulado com feijão-caupi apresentou valor superior de cinzas, proteínas, carboidratos e minerais (cobre, ferro, fósforo, magnésio, manganês e zinco) além de redução da umidade, do teor de lipídios, valor energético total e sódio comparando-se com a formulação padrão. Assim, o produto elaborado apresentou-se enriquecido, com o acréscimo de minerais e macronutrientes, tornando a substituição parcial de polvilho doce por farinha de feijão-caupi (FFC) na elaboração de pães de queijo possível e relevante.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/377a.pdf. Acesso em: 09 ago. 2013

    Cheese bread enriched with biofortified cowpea and theirsensory, and nutritional characteristics.

    Get PDF
    Biofortified agricultural products complement existing nutritional interventions. These foods reach populations with limited access to formal health and market systems

    The effect of seasoning with herbs on the nutritional, safety and sensory properties of reduced-sodium fermented Cobrançosa cv. table olives

    Get PDF
    This study aimed at evaluating the effectiveness of seasoning Cobrancosa table olives in a brine with aromatic ingredients, in order to mask the bitter taste given by KCl when added to reduced-sodium fermentation brines. Olives were fermented in two different salt combinations: Brine A, containing 8% NaCl and, Brine B, a reduced-sodium brine, containing 4% NaCl + 4% KCl. After the fermentation the olives were immersed in seasoning brines with NaCl (2%) and the aromatic herbs (thyme, oregano and calamintha), garlic and lemon. At the end of the fermentation and two weeks after seasoning, the physicochemical, nutritional, organoleptic, and microbiological parameters, were determined. The olives fermented in the reduced-sodium brines had half the sodium concentration, higher potassium and calcium content, a lower caloric level, but were considered, by a sensorial panel, more bitter than olives fermented in NaCl brine. Seasoned table olives, previously fermented in Brine A and Brine B, had no significant differences in the amounts of protein (1.23% or 1.11%), carbohydrates (1.0% or 0.66%), fat (20.0% or 20.5%) and dietary fiber (3.4% or 3.6%). Regarding mineral contents, the sodium-reduced fermented olives, presented one third of sodium, seven times more potassium and three times more calcium than the traditional olives fermented in 8% NaCl. Additionally, according to the panelists' evaluation, seasoning the olives fermented in 4% NaCl + 4% KCl, resulted in a decrease in bitterness and an improvement in the overall evaluation and flavor. Escherichia coli and Salmonella were not found in the olives produced.info:eu-repo/semantics/publishedVersio
    corecore