1,910 research outputs found

    Segregation-induced grain boundary electrical potential in ionic oxide materials: A first principles model

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    A first principles continuum analytical model for cationic segregation to the grain boundaries in complex ceramic oxides is presented. The model permits one to determine the electric charge density and the segregation-induced electric potential profiles through the grain and can be extrapolated to the range of nanostructured grain sizes. The theoretical predictions are compared with existing data for yttria-stabilized tetragonal zirconia polycrystals. The implications for physical properties (mainly high temperature plasticity and hardening behaviour) are then discussed.Gobierno de España MAT2009-14351-C02-01, MAT2009-14351-C02-0

    Systematic Study of the Content of Phytochemicals in Fresh and Fresh-Cut Vegetables

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    Vegetables and fruits have beneficial properties for human health, because of the presence of phytochemicals, but their concentration can fluctuate throughout the year. A systematic study of the phytochemical content in tomato, eggplant, carrot, broccoli and grape (fresh and fresh-cut) has been performed at different seasons, using liquid chromatography coupled to triple quadrupole mass spectrometry. It was observed that phenolic acids (the predominant group in carrot, eggplant and tomato) were found at higher concentrations in fresh carrot than in fresh-cut carrot. However, in the case of eggplant, they were detected at a higher content in fresh-cut than in fresh samples. Regarding tomato, the differences in the content of phenolic acids between fresh and fresh-cut were lower than in other matrices, except in winter sampling, where this family was detected at the highest concentration in fresh tomato. In grape, the flavonols content (predominant group) was higher in fresh grape than in fresh-cut during all samplings. The content of glucosinolates was lower in fresh-cut broccoli than in fresh samples in winter and spring sampling, although this trend changes in summer and autumn. In summary, phytochemical concentration did show significant differences during one-year monitoring, and the families of phytochemicals presented different behaviors depending on the matrix studied

    Lectotypification, geographic distribution and conservation status of Cephalanthus glabratus (Naucleeae-Rubiaceae)

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    Cephalanthus glabratus is an imperfectly known species of the family Rubiaceae. It is a medicinal plant widely used by the locals in its area of distribution, however until now it has received little attention from the scientific community, which is evidenced in the few articles treating the species. The species is a much-branched shrub, with whorled leaves, glomeriform inflorescences, schizocarpic fruits with 1-seeded mericarps, and seeds with a large spongy strophiole. It grows only in the vegetation of the lowlands and is always related to the basins of the main rivers of the region, Paraguay, Paraná, Uruguay and Río de la Plata, and therefore is strongly threatened by the human activities along them (hydroelectric dams, deforestation, advances of urban areas, reduction of the wetlands, etc.). Following IUCN guidelines and all available distributional data, we rated it NT (Near Threatened). Despite the fact that the genus was taxonomically revised, the nomenclatural type of Cephalanthus glabratus was not correctly clarified, so we have done so here. A detailed description, ecological and distributional data are provided.Cephalanthus glabratus é uma espécie imperfeitamente conhecida da família Rubiaceae. Esta é uma planta medicinal muito utilizada pelos habitantes locais em sua área de distribuição, porém até agora tem recebido escassa atenção da comunidade científica, o qual é evidenciado na escassa literatura que trata do táxon. A espécie é um arbusto muito ramificado, com folhas verticiladas, inflorescências em glomérulos, fruto esquizocárpico, uma semente por mericarpo, e sementes com um estrofiolo proeminente e esponjoso. A espécie cresce somente em vegetação de áreas baixas alagáveis e está sempre relacionada às bacias dos principais rios da região, Paraguai, Paraná, Uruguai e Rio da Prata, e, portanto, é fortemente ameaçada pelas atividades humanas ao longo delas (hidrelétricas, desmatamento, avanços das áreas urbanas, redução das zonas úmidas etc.). Seguindo as diretrizes da IUCN e baseado em todos os dados disponíveis de distribuição, classificamos como NT (Near Threatened, quase ameaçada). Apesar de que gênero foi taxonomicamente revisado, a nomenclatura do tipo de Cephalanthus glabratus não foi por enquanto corretamente estudada, portanto, é revisada aqui. Uma descrição detalhada, dados ecológicos e de distribuição são adicionalmente fornecidos.Fil: Romero, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Salas, Roberto Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: González, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

    Modificación de un sistema diseñado para la producción y la purificación de hidrógeno sin emisiones de CO2 mediante el proceso “steam iron”: adición de óxido de molibdeno al sólido utilizado en el reactor

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    - Determinación de la concentración óptima de molibdeno en el sólido preparando diferentes muestras de sólido dentro de un rango de concentraciones. - Comprobar si se produce descomposición de metano en el proceso “steam-iron” utilizando el sólido optimizado. - Comprobación de la estabilidad del mejor sólido de molibdeno en sucesivos ciclos de oxidación y reducción en termobalanza y lecho fijo y la comparación con la de otros sólidos

    Monitoring of Volatile Additives from Plant Protection Products in Tomatoes Using HS-SPME-GC-HRMS: Targeted and Suspect Approaches

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    Additives present in plant protection products (PPPs) are normally not monitored after sample treatments. In this study, the fate of additives detected by targeted and nontargeted analysis in tomato samples treated with two PPPs was carried out. The study was carried out in a greenhouse for 12 days, in which two applications with each PPP were made. Compounds were extracted by applying a headspace solid phase microextraction (HS-SPME) and analyzed by gas chromatography coupled to high resolution mass spectrometry (GC-HRMS), performing targeted and suspect approaches. Three targeted and 15 nontargeted compounds were identified at concentration levels of up to 150 μg/kg. Compounds detected encompassed benzene, toluene, indene, and naphthalene derivatives, as well as conservatives and flavouring compounds. Most of them degraded in less than 7 days after the second application, following first-order kinetic. This study aims to reduce knowledge gaps regarding additives and their fate under real climatic conditions of greenhouses cultivations.Spanish Ministry of Economy and Competitiveness (MINECO)FEDER-EU (project PID2019-106201RB-I00)Regional Government of Andalusia, SpainEuropean funds for financial support (project P18- RT-2329)Andalusian Ministry of Economic Transformation, Industry, Knowledge and Universities for financial support from “Ayudas para Captación, Incorporación y Movilidad de Capital Humano de I+D+i (PAIDI 2020)”University of Almería for his “Convocatoria de Recualificación do Sistema Universitario Español-Margarita Salas”“Plan de Recuperación Transformación” program funded by the Spanish Ministry of UniversitiesEuropean Union’s NextGenerationEU fund

    Determination of atropine and scopolamine in bluckwheat and related products using modified QuEChERS and liquid chromatography tándem mass spectrometry

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    Buckwheat is a healthy pseudo cereal widely cultivated over the world as an important raw material used for functional food because it becomes a dietary source of bioactive compounds, such as nutritionally valuable protein, phenolic compounds, starch and dietary fiber, essential minerals and trace elements. However, buckwheat can be contaminated by stramonium (Datura stramonium), which can contain high concentration of tropane alkaloids, and therefore, these toxic substances can be found in buckwheat and related matrices at concentrations higher than 100 μg/kg [1]. Tropane alkaloids are synthesized by the plants of the genus from Solanaceae family, although they are also produced in smaller quantities in plants from other families. They can affect human and animal health due to their high toxicity and intake of contaminated food or animal feed. Although there are more than 200 tropane alkaloids, atropine and scopolamine are the most common compounds of this family. According to the EFSA scientific opinion in 2013 [1] more attention must be focused on the contaminated levels of atropine and scopolamine in food from plant origin, such as cereal products, grain-based baby-food, buckwheat grain and food products and tea and herbal infusions. Therefore, the development of quick, easy and reliable analytical methods for the trace analysis of tropane alkaloids at trace levels in food from plant origin is desirable. Therefore the aim of this study is the development and validation of an analytical method for the simultaneous determination of atropine and scopolamine residues in buckwheat and related products. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction method with acidified acetonitrile (1% formic acid v/v) followed by a clean-up step using graphitized black carbon (GBC) and primary secondary amine (PSA) was applied. For the separation and quantification of the target compounds, ultra high performance liquid chromatography (UHPLC)-coupled to tandem mass spectrometry (MS/MS), utilizing triple quadrupole (QqQ) as analyzer, was used. The method was validated, determining linearity, trueness, precision, limits of detection (LODs) and quantification (LOQs). Recoveries ranged from 75 to 92% with precision below 17% (RSD values) for all the compounds studied. Both LODs and LOQs were below 2 μg kg-1. The validated method was tested in eight commercial samples (buckwheat, wheat, soy, buckwheat flour, buckwheat noodle, amaranth grain, chia seeds and peeled millet). Target compounds were not found above the detection limits of the method

    Extracting diagnostic knowledge from MedLine Plus: a comparison between MetaMap and cTAKES Approaches

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    The development of diagnostic decision support systems (DDSS) requires having a reliable and consistent knowledge base about diseases and their symptoms, signs and diagnostic tests. Physicians are typically the source of this knowledge, but it is not always possible to obtain all the desired information from them. Other valuable sources are medical books and articles describing the diagnosis of diseases, but again, extracting this information is a hard and time-consuming task. In this paper we present the results of our research, in which we have used Web scraping, natural language processing techniques, a variety of publicly available sources of diagnostic knowledge and two widely known medical concept identifiers, MetaMap and cTAKES, to extract diagnostic criteria for infectious diseases from MedLine Plus articles. A performance comparison of MetaMap and cTAKES is also presented

    A self-determined exploration of adolescents’ and parents’ experiences derived from a multidimensional school-based physical activity intervention

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    Purpose: Adolescents’ and parents’ experiences within a multidimensional schoolbased physical activity intervention grounded on self-determination theory were explored. Method: Qualitative data from 29 adolescents (aged 15-17 years) and three parents on behalf of the total students' families were collected via participant observation (research diary), semistructured interviews, and focus groups. Results: Adolescents perceived that the application of motivational strategies, based on selfdetermination theory, satisfied their basic psychological needs for autonomy, competence and relatedness, favored self-determined motivation, and gave rise to adaptive consequences (improved physical activity knowledge, creation of affective bonds, and increased leisure-time physical activity). These results were supported by the information reported by the students' parents. Discussion/Conclusions: The findings support the implementation of self-determination theory-based multidimensional interventions to promote adolescents’ physical activity participation. This study also presents several motivational strategies which could be useful for the design and implementation of future school-based physical activity intervention
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