918 research outputs found

    Structure, electronic properties, morphology evolution, and photocatalytic activity in PbMoO4 and Pb12xCaxSrxMoO4 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) solid solutions

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    In this work PbMoO4 and Pb12xCaxSrxMoO4 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) solid solutions have been successfully prepared, for the first time, by a simple co-precipitation method and the as-synthesized samples were subjected to a water-based reflux treatment. Structural characterization of these samples was performed using X-ray diffraction with Rietveld refinement analysis and Raman spectroscopy. Their optical properties were investigated by UV-Vis absorption spectroscopy and PL emissions, and the photocatalytic activity of the as-synthesized samples for the degradation process of Rhodamine B has been demonstrated. The surface structure and morphologies were characterized by field emission scanning electron microscopy. To complement and rationalize the experimental results, the geometry, electronic structures, and morphologies of as-synthesized samples were characterized by first-principles quantum-mechanical calculations at the density functional theory level. By using Wulff construction, based on the values of the surface energies for the (001), (100), (110), (111), (011) and (112) surfaces, a complete map of the available morphologies for PbMoO4 was obtained and a good agreement between the experimental and theoretical predicted morphologies was found. The structural and electronic changes induced by the substitution of Pb by Ca and Sr allow us to find a relationship among morphology, the electron-transfer process at the exposed surfaces, optical properties, and photocatalytic activity. We believe that our results offer new insights regarding the local coordination of superficial Pb/Ca/Sr and Mo cations (i.e., clusters) on each exposed surface of the corresponding morphology, which dictate the photocatalytic activities of the as-synthesized samples, a field that has so far remained unexplored. The present study, which combines multiple experimental methods and first-principles calculations, provides a deep understanding of the local structures, bonding, morphologies, band gaps, and electronic and optical properties, and opens the door to exploit the electrical, optical and photocatalytic activity of this very promising family of materials

    Valorization of Oleuropein via Tunable Acid-Promoted Methanolysis

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    The acid-promoted methanolysis of oleuropein was studied using a variety of homogeneous and heterogeneous acid catalysts. Exclusive cleavage of the acetal bond between the glucoside and the monoterpene subunits or further hydrolysis of the hydroxytyrosol ester and subsequent intramolecular rearrangement were observed upon identification of the most efficient catalyst and experimental conditions. Furthermore, selected conditions were tested using oleuropein under continuous flow and using a crude mixture extracted from olive leaves under batch. Formation of (−)-methyl elenolate was also observed in this study, which is a reported precursor for the synthesis of the antihypertensive drug (−)-ajmalicine.Centro de Investigación y Desarrollo en Ciencias Aplicada

    Estudos sobre a paz e cultura da paz

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    Segundo o autor, a cultura da paz implica uma mudança quer na forma como a “alta cultura” lida com a realidade quer no tipo de abordagem que o senso comum faz às relações sociais, sendo que a ruptura com a ideologia conservadora, ou seja, com o senso comum realista só é possível graças a estas alterações. O autor realça tanto a importância que os estudos sobre a paz têm para o surgimento de um conceito amplo de paz, desenvolvido por Johan Galtung, como o facto destes estarem estrategicamente orientados para a transformação do sistema internacional. Sequentemente, conclui que a paz é uma categoria moral e cultural que só pode ser alcançada através do comportamento quotidian

    Shedding light on the Holocephali taxonomy, the mitogenome of Chimaera opalescens

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    Cartilaginous fish (Chondrichthyes), i.e. sharks, rays, and chimaeras, are extremely interesting from a biological perspective as they represent one of the oldest and most ecologically diverse groups of jawed vertebrates. Their K-selective reproductive traits, make them vulnerable to overfishing. Chimaerid are also a frequent by-catch of deep-water fisheries. Holocephalans comprise a single surviving order, the Chimaeriformes, and are allocated into three different families: Callorhinchidae, Rhinochimaeridae and Chimaeridae (Weigmann 2016). Furthermore, the family Chimaeridae only includes two genera: Chimera and Hydrolagus. Recently, several new species have been described (Iglesias et al., 2022), including Chimera opalescens from deep-sea assemblages (Luchetti et al., 2011). However, previous records of C. opalescens were erroneously classified as Chimera monstrosa (Luchetti et al., 2011; Catarino et al., 2020), due to the similar morphology (Luchetti et al., 2011), which highlights the critical importance of molecular approaches to support species identification. Mitogenomes have been a powerful tool used to elucidate phylogenetic relationships, both at deep and at shallow evolutionary nodes. The development of long-read sequencing technologies a precise and reliable assembly of complete mtDNA genomes. The sequencing and characterization of the complete mitogenome of the opal chimera Chimera opalescens (Luchetti, Iglesias et al., 2011) was carried out, using the long-read technique PacBio HiFi. The entire mitogenome was 23,411 bp long and shows the same overall content, i.e. 13 protein-coding genes, 22 transfer RNA and 2 ribosomal RNA genes, as all other examined chondrichthyan mitogenomes. Phylogenetic reconstructions using all available Chondrichthyan mitogenomes, including 11 Holocephali (chimeras and ratfishes), places C. opalescens within the Chimaeridae family. Furthermore, the results reinforce previous findings, showing the genus Chimera as paraphyletic and thus highlighting the need to expand molecular approaches in this group of cartilaginous fishes

    INTOXICAÇÃO POR PTERIDIUM ARACHNOIDEUM NO OESTE DE SANTA CATARINA - ESTUDO RETROSPECTIVO (2013-2017)

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    Samambaia (Pteridium arachnoideum) é uma das plantas tóxicas mais importantes na criação de bovinos de todo o Brasil. O objetivo desse trabalho foi descrever os diagnósticos de intoxicação por samambaia, em bovinos na região oeste de Santa Catarina, realizados pelo Laboratório de Patologia Veterinária (LPV) do IFC – Campus Concórdia, no período entre 2013 e 2017. No período, foram realizadas 641 necropsias de bovinos, sendo que 22 dessas tiveram o diagnóstico de intoxicação por samambaia, totalizando 3,4% da casuística total de necropsias em bovinos. Foram 13 casos de síndrome hemorrágica aguda, seis casos de carcinomas de células escamosas na base da língua, esôfago ou rúmen, e três casos de hematúria enzoótica bovina. Apesar dos inúmeros trabalhos científicos a respeito da toxicidade do P. arachnoideum, o número de diagnósticos dessa intoxicação é alto na região, e a planta ainda é facilmente encontrada. A melhor forma de diminuir as intoxicações é o adequado manejo das pastagens e a correta adubação do solo, evitando com que a planta esteja disponível ao consumo dos animais, porém essa informação precisa ser difundida aos produtores rurais.  Palavras-chave: diagnóstico, patologia, samambaia, hematúria, carcinoma.

    INTOXICAÇÃO POR NITRATO/NITRITO NO OESTE DE SANTA CATARINA - ESTUDO RETROSPECTIVO (2013-2017)

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    A intoxicação por nitrato/nitrito é uma enfermidade comum no estado de Santa Catarina, e que leva a morte súbita em bovinos. Trata-se de um distúrbio ocasionado pela utilização excessiva de adubação nitrogenada nas pastagens e condições climáticas adversas, como diminuição de luminosidade ou déficit hídrico, levando ao acúmulo de nitrato na pastagem. Este trabalho teve como objetivo relatar a ocorrência dos casos de intoxicação por nitrato/nitrito em bovinos na região oeste de Santa Catarina, diagnosticados pelo Laboratório de Patologia Veterinária (LPV) do Instituto Federal Catarinense – Campus Concórdia. Entre os anos de 2013 e 2017, foram diagnosticados por necropsia 10 surtos de intoxicações por nitrato/nitrito. De um total de 641 bovinos necropsiados pelo LPV nesse período, 19 correspondem a essa intoxicação, representando 2,96% da casuística de necropsias e 2,20% da casuística total de diagnósticos (necropsias e histopatológico). Ainda que seja um número expressivo de causa mortis, acredita-se que existam muitos outros casos não diagnosticados pelo LPV, visto que nem todos os animais são remetidos para necropsia. Conclui-se que as intoxicações por nitrato/nitrito são expressiva causa de morte nos rebanhos bovinos da região, devendo serem adotadas medidas de controle e prevenção. Palavras-chave: metemoglobina, patologia, bovino, diagnóstico, necropsia. 

    Application of the comet assay in the evaluation of the semi-synthetic n-butyl dillapiole ether in Balb/C mice.

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    The semi-synthetic n-butyl ether dillapiole (EBD) has a potential effect on the control of Aedes aegypti, the vector of the dengue, Zika, chikungunya, and yellow fever virus. However, there are no studies on the risk of exposure to this compound to the health of humans and other animals. In this sense, the Comet Assay Test is used to detect genomic lesions that can result in mutations. Objective: evaluate the incidence of DNA damage in blood cells of isogenic mice treated with EBD
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