812 research outputs found

    Hydrothermal synthesis to water-stable luminescent carbon dots from acerola fruit for photoluminescent composites preparation and its application as sensors

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    Carbon dots (C-dots) possess the attractive properties of high stability, low toxicity, good water solubility, simple synthetic routes as well as size and excitation-dependent photoluminescence (PL).The aim of this work was to synthesize photoluminescent C-dots by hydrothermal method using acerola fruit (Malpighiaemarginata) as a row material, since this fruit contains large number of organic molecules. Studies about the optimal synthesis conditions were performed, where these organic molecules were converted into C-dots by hydrothermal carbonization at 180 ºC for 18 h. The C-dots exhibited a green emission light at 459 nm when excited under UV-light (λ ex= 370 nm). These nanomaterials were also successfully used to prepare C-dots/poly (vinyl alcohol) luminescent composites (C-dots/PVA). Both C-dots and C-dots/PVA composite films were investigated by using colorimetric visual sensor for Fe3+ metal ions detection. The results show that the prepared C-dots and C-dots/poly presented strong green emission light. The emission spectra of above materials were quenched in the presence of Fe3+ ions. Thus, highly specific “turn off” fluorescence sensing of Fe3+ was achieved using fluorescent C-dots. Regarding, this work describe that the polymeric films as sensors of metallic ions in aqueous solution appears as a new perspectives to design new composite materials22

    Evaluation of the fungitoxic activity and isolation of alloaromadendrene - 4α, 10 β - diol in Hypericum cordatum

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    The Hypericum cordatum is a species of the Brazilian Cerrado that was selected in a screening of plants with fungitoxic activities. The aim of this work was to isolate and identify the compounds with antifungal activity in leaf extracts in dichloromethane. For this end, the powder made from the leaves of the plants was submitted to exhaustive extraction with petroleum ether and dichloromethane. The extract in dichloromethane and the active fractions were submitted to bioassay-guided fractionation in Sephadex LH - 20 column, respectively, with the following eluents chloroform:methanol (1:1) and a gradient of hexane:dichlorometane (1:4); dichloromethane:acetone (3:3 and 1:4), methanol and water. Afterward, the fractions that showed some activity were submitted to preparative thin layer chromatography of silica gel GF254 and the material with the greatest mass was submitted to semi-preparative HPLC. The active fraction obtained was analyzed by ¹H NMR, and the main component identified was alloaromadendrene-4α-10β - diol. We may then conclude that this is one of the compounds responsible for the fungitoxic activity of Hypericum cordatum.Hypericum cordatum é uma espécie do cerrado que foi selecionada em triagem de plantas com atividade fungitóxica. O objetivo do presente trabalho foi isolar e identificar compostos com atividade antifúngica em extratos de folhas em diclorometano. O pó das folhas das plantas foi submetido à extração exaustiva com éter de petróleo e diclorometano. O extrato em diclorometano, e as frações ativas, foram submetidos à fracionamentos biomonitorados em coluna de Sephadex LH-20, respectivamente, com os eluentes clorofórmio:metanol (1:1) e com um gradiente de hexano:diclorometano (1:4); diclorometano:acetona (3:2 e 1:4), metanol, e água. As frações que mostraram atividade foram submetidas à cromatografia em camada delgada preparativa de sílica gel GF254, sendo que o material de maior massa foi analisado em CLAE semipreparativa. A fração ativa foi analisada por RMN de ¹H, tendo sido identificado o aloaromadendrano - 4α -10β - diol como componente principal da fração. Conclui-se, portanto, que este é um dos compostos responsáveis pela atividade fungitóxica de Hypericum cordatum.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Instituto de Botânica Núcleo de Pesquisa em Fisiologia e BioquímicaUniversidade Federal de São Paulo (UNIFESP) Departamento de Ciências Exatas e da TerraUNIFESP, Depto. de Ciências Exatas e da TerraSciEL

    Gomphrena claussenii, the first South-American metallophyte species with indicator-like Zn and Cd accumulation and extreme metal tolerance

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    Plant species with the capacity to tolerate heavy metals are potentially useful for phytoremediation since they have adapted to survive and reproduce under toxic conditions and to accumulate high metal concentrations. Gomphrena claussenii Moq., a South-American species belonging to the Amaranthaceae, is found at a zinc (Zn) mining area in the state of Minas Gerais, Brazil. Through soil and hydroponic experiments, the metal tolerance and accumulation capacities of G. claussenii were assessed and the effects on physiological characteristics were compared with a closely related non-tolerant species, G. elegans Mart. G. claussenii plants grown in soil sampled at the Zn smelting area accumulated up to 5318µgg-1 of Zn and 287 µg g-1 of cadmium (Cd) in shoot dry biomass after 30 days of exposure. Plants were grown in hydroponics containing up to 3000 µM of Zn and 100 µM of Cd for G. claussenii and 100 µM of Zn and 5 µM of Cd for G. elegans. G. claussenii proved to be an extremely tolerant species to both Zn and Cd, showing only slight metal toxicity symptoms at the highest treatment levels, without significant decrease in biomass and no effects on root growth, whereas the non-tolerant species G. elegans showed significant toxicity effects at the highest exposure levels. Both species accumulated more Zn and Cd in roots than in shoots. In G. elegans, over 90% of the Cd remained in the roots, but G. claussenii showed a root:shoot concentration ratio of around 2, with shoots reaching 0.93% Zn and 0.13% Cd on dry matter base. In G. claussenii shoots, the concentrations of other minerals, such as iron (Fe) and manganese (Mn), were only affected by the highest Zn treatment while in G. elegans the Fe and Mn concentrations in shoots decreased drastically at both Zn and Cd treatments. Taking together, these results indicate that G. claussenii is a novel metallophyte, extremely tolerant of high Zn and Cd exposure and an interesting species for further phytoremediation studies Keywords: phytoremediation, Zn/Cd hypertolerance, hyperaccumulation, metal contamination, Gomphrena claussenii, Gomphrena elegan

    FGFR1 and PROKR2 rare variants found in patients with combined pituitary hormone deficiencies.

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    The genetic aetiology of congenital hypopituitarism (CH) is not entirely elucidated. FGFR1 and PROKR2 loss-of-function mutations are classically involved in hypogonadotrophic hypogonadism (HH), however, due to the clinical and genetic overlap of HH and CH; these genes may also be involved in the pathogenesis of CH. Using a candidate gene approach, we screened 156 Brazilian patients with combined pituitary hormone deficiencies (CPHD) for loss-of-function mutations in FGFR1 and PROKR2. We identified three FGFR1 variants (p.Arg448Trp, p.Ser107Leu and p.Pro772Ser) in four unrelated patients (two males) and two PROKR2 variants (p.Arg85Cys and p.Arg248Glu) in two unrelated female patients. Five of the six patients harbouring the variants had a first-degree relative that was an unaffected carrier of it. Results of functional studies indicated that the new FGFR1 variant p.Arg448Trp is a loss-of-function variant, while p.Ser107Leu and p.Pro772Ser present signalling activity similar to the wild-type form. Regarding PROKR2 variants, results from previous functional studies indicated that p.Arg85Cys moderately compromises receptor signalling through both MAPK and Ca(2) (+) pathways while p.Arg248Glu decreases calcium mobilization but has normal MAPK activity. The presence of loss-of-function variants of FGFR1 and PROKR2 in our patients with CPHD is indicative of an adjuvant and/or modifier effect of these rare variants on the phenotype. The presence of the same variants in unaffected relatives implies that they cannot solely cause the phenotype. Other associated genetic and/or environmental modifiers may play a role in the aetiology of this condition

    Comparação Da Qualidade Nutricional Das Refeições Antes E Depois Do Plano Nacional De Assistência Estudantil No Rj, Brasil

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    The Brazilian National Plan for Student Assistance (NPSA) aims at improving overall academic performance of undergraduate student. It is important to identify whether the investment in food assistance had a positive impact on the nutritional quality of meals. Aims: To compare the nutritional quality of meals in a university restaurant (UR) before and after the restructure by NPSA. Methods: The portioning of meals at lunch as served to students was registered in 2011 (Phase I) and 2013 (Phase II) for determination of percent carbohydrates, proteins and lipids, as well as the total energy value (TEV), cholesterol, sodium, and fruits and vegetables (FV). The meal quality index (MQI) was estimated from those observations at both phases. Portioning of meals and MQI were compared between phases, and according to current recommendations. Results: Significant lower values of TEV, lipid, cholesterol and sodium were observed at Phase II (p<0.001 all comparisons). Conversely, significant higher values of proteins and FV were observed at Phase II (p<0.001 both comparisons). The number of meals within the recommended MQI was significantly higher (p<0.001) at Phase II (73.1%) than Phase I (47.7%), whereas the proportion of meals with proteins, FV, cholesterol and sodium was significantly higher (p<0.001). Conclusions: Nutritional quality of meals at an UR improved after the implementation of the NPSA. Nonetheless, serving standard meals is strongly recommended, mainly regarding salt intake. Finally, these data highlight the need for educational actions with undergraduate students aiming to reduce salt intake and proper portioning of the meal. © Copyright 2012. Fundación Alimentación Saludable.362748

    EFEITO DA UMIDADE E DA TEMPERATURA NO PROCESSAMENTO DE FARINHA DE BANANA VERDE (Musa acuminata, GRUPO AAA) POR EXTRUSÃO TERMOPLÁSTICA

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    Testou-se a utilização de farinha de banana da variedade Nanicão no processo de extrusão termoplástico, visando analisar as características dos produtos obtidos em função das variáveis umidade e temperatura de extrusão. Os experimentos variaram em torno dos pontos centrais de umidade e temperatura de 20% e 150ºC, respectivamente, observando-se o efeito conjugado dessas variáveis sobre as características físicas e físico-químicas dos produtos extrusados. O processo de extrusão propiciou grande degradação do amido de banana e as amostras apresentaram elevado grau de gelatinização em todas as condições estudadas. O índice de solubilidade aumentou com a elevação da temperatura e diminuição da umidade. Verificou-se maior viscosidade de pasta a frio e a quente com aumento da umidade da matéria-prima. As maiores taxas de expansão foram obtidas com temperaturas mais elevadas e umidades mais baixas. A energia mecânica específica foi reduzida conforme o aumento da umidade e da temperatura de extrusão. Confirmou-se a quebra da molécula de amido sob as condições de extrusão pela redução do conteúdo de amido das amostras

    Relationship between the amount of AgNORs, proliferative activity and stage of placental development in horses

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    As Regiões Organizadoras de Nucléolo (NORs - nucleolar organizer regions) são utilizadas para descrever regiões de cromatina coradas por Nitrato de Prata e estão relacionados com a atividade de síntese de RNAr e com a agilidade e rapidez na proliferação celular nos tecidos estudados. O objetivo deste trabalho foi relacionar a quantidade de AgNORs, a atividade proliferativa e o estágio da gestação em equinos, utilizando a coloração de Nitrato de Prata. Os anexos embrionários foram coletados, fixados em solução de formaldeído tamponado 10%, emblocadas em paraplast e submetidos à coloração de Nitrato de Prata. Os grupos foram determinados de acordo com a idade gestacional. A quantidade de NORs encontrada no cório no começo da gestação indica início da atividade celular e na medida em que a gestação avança, a quantidade de NORs aumenta, sugerindo maior atividade de síntese e aumento da sua importância na manutenção do feto. Ao contrário do que ocorre no cório, a quantificação das NORs foram maiores no final da gestação do que no inicio, sugerindo a estabilização destas membranas no final da gestação. A cinta coriônica e o saco vitelino foram encontrados no início da gestação e apresentaram grande quantidade de NORs, sugerindo função de síntese e proliferação no inicio da gestação, visto que suas funções é manutenção do embrião até a formação completa da placenta verdadeira (cório-alantoide). Concluímos que as membranas que se desenvolvem de maneira progressiva de acordo com o crescimento embrionário/fetal (cório, alantoide e âmnio) têm aumento no número de NORs e as membranas que involuem após a formação do embrião/feto (saco vitelino e cinta coriônica) têm um decréscimo neste número, sugerindo a diminuição da atividade proliferativa nestas membranas
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