192 research outputs found

    Influence of different protecting groups on the regioselectivity of the hydrotelluration reaction of hydroxy alkynes

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    The influence of protecting groups on the synthesis of regio- and stereodefined vinyl tellurides derived from the reaction of BuTeNa and propargylic- or homo-propargylic alcohols showed that TIPS silyl ether is useful as a regiodirecting group. The application of the methodology to the synthesis of a fragment of (±)-Seselidiol, a natural product, demonstrated the applicability of the new methodology

    Technological Applications of Porphyrins and Related Compounds: Spintronics and Micro-/Nanomotors

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    The vital role played by porphyrins in cells and their use in therapeutic processes are well known. More recently, the technological applications of porphyrins have attracted the attention of researchers. Porphyrins have the property of half-metallic material, i.e., molecules that can host transition metals making feasible the production of spin-polarized electronic states at different channels. Therefore, porphyrins and hemeproteins are among the materials that have spin-filtering property to be applied in spintronics. Molecular spintronics is an emerging and highly relevant field due to their applications to the development of high-capacity information-storage devices and quantum computers. The catalytic properties of porphyrins and related compounds such as the hemeproteins are also applicable in the fabrication of micro-/nanomotors (MNMs). In this chapter, we describe the advances and future perspectives in the technological applications of porphyrins and related compounds in spintronic devices and micro-/nanomotors

    Diversidade de Coccinellidae (Coleoptera) em plantas aromáticas (Apiaceae) como sítios de sobrevivência e reprodução em sistema agroecológico.

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    Studies show that Apiaceae may provide concentrated vital resources for predator insects,stimulating their abundance, diversity and persistence in agricultural systems, thereby increasing their effi ciency as biological control agents. Among the predatory insects, Coccinellidae (Coleoptera) on many different species both as larvae and adults, complementing their diet with pollen and/or nectar. This study aimed to determine the diversity and relative abundance of Coccinellidae species visiting plants of Anethum graveolens (dill), Coriandrum sativum (coriander) and Foeniculum vulgare (sweet fennel) (all Apiaceae), particularly in their blooming seasons, and to evaluate the potential of these aromatic species for providing the resources for survivorship and reproduction of coccinelids. Coccinellids were collected by removal of samplings from September to October, 2007. Besides one unidentifi ed species of Chilocorinae, five species of Coccinellinae were collected: Coleomegilla maculata DeGeer, Coleomegilla quadrifasciata (Schönherr), Cycloneda sanguinea (L.), Eriopis connexa (Germar) and Hippodamia convergens Guérin-Meneville. Dill provided a signifi cant increase in the abundance of coccinellids as compared to coriander and sweet fennel. These aromatic species were used by coccinellids as survival and reproduction sites, providing food resources (pollen and/or prey), shelter for larvae, pupae and adults, and mating and oviposition sites as well

    ESPAÇO COLABORATIVO COMO FERRAMENTA DE GESTÃO: UM ESTUDO DE CASO EM UMA INSTITUIÇÃO DE ENSINO SUPERIOR

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    A proposta central deste artigo está na sistematização do espaço colaborativo como meio para o gerenciamento das atividades dos tutores presenciais, voltado para o suporte das atividades administrativas dos cursos de graduação em Administração e Administração Pública na modalidade a distância, ofertados pela Universidade Federal de Santa Catarina (UFSC). Em relação aos procedimentos metodológicos a pesquisa classificou-se como descritiva, aplicada, estudo de caso, documental e bibliográfica. Para a coleta de dados foram realizadas entrevistas com os envolvidos (tutores presenciais, coordenadores de pólo e supervisora). Observou-se que o espaço colaborativo constitui-se em um elemento facilitador das atividades de ordem administrativa, no sentido de melhoria na qualidade do feedback, bem como agilidade no tempo de resposta e, principalmente, pela facilidade de acesso as informações, tornando-as comuns a toda a equipe

    A Autocaptura Ventricular e o Aumento da Longevidade da Bateria do Marcapasso

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    Uma das grandes restriçoes para o aumento da longevidade dos marcapassos é a necessidade de grandes quantidades de energia (acima do limiar de estimulaçao) para garantir uma estimulaçao segura. O objetivo deste trabalho é analisar a performance de um algoritmo baseado na presença ou ausência do potencial evocado pós-estimulaçao ventricular, que permite reduzir com segurança a energia do pulso do marcapasso a valores próximos do limiar crônico de estimulaçao. Entre Janeiro e Agosto de 1997 um marcapasso Logos DDD (Biotronik), que apresenta este algoritmo foi instalado, em 10 pacientes, sendo 7 do sexo masculino e 3 do sexo feminino. Pela análise do algoritmo constatou-se a efetividade do auto-teste no controle da captura ventricular, bem como a confiabilidade e a segurança na estimulaçao através da análise do Holter 24 horas. Verificou-se assim que é possível aumentar com segurança a longevidade do marcapasso através da diminuiçao da energia do pulso

    A Autocaptura Ventricular e o Aumento da Longevidade da Bateria do Marcapasso

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    Uma das grandes restriçoes para o aumento da longevidade dos marcapassos é a necessidade de grandes quantidades de energia (acima do limiar de estimulaçao) para garantir uma estimulaçao segura. O objetivo deste trabalho é analisar a performance de um algoritmo baseado na presença ou ausência do potencial evocado pós-estimulaçao ventricular, que permite reduzir com segurança a energia do pulso do marcapasso a valores próximos do limiar crônico de estimulaçao. Entre Janeiro e Agosto de 1997 um marcapasso Logos DDD (Biotronik), que apresenta este algoritmo foi instalado, em 10 pacientes, sendo 7 do sexo masculino e 3 do sexo feminino. Pela análise do algoritmo constatou-se a efetividade do auto-teste no controle da captura ventricular, bem como a confiabilidade e a segurança na estimulaçao através da análise do Holter 24 horas. Verificou-se assim que é possível aumentar com segurança a longevidade do marcapasso através da diminuiçao da energia do pulso

    A comparison of two distinct murine macrophage gene expression profiles in response to Leishmania amazonensis infection

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    <p>Abstract</p> <p>Background</p> <p>The experimental murine model of leishmaniasis has been widely used to characterize the immune response against <it>Leishmania</it>. CBA mice develop severe lesions, while C57BL/6 present small chronic lesions under <it>L. amazonensis </it>infection. Employing a transcriptomic approach combined with biological network analysis, the gene expression profiles of C57BL/6 and CBA macrophages, before and after <it>L. amazonensis </it>infection in vitro, were compared. These strains were selected due to their different degrees of susceptibility to this parasite.</p> <p>Results</p> <p>The genes expressed by C57BL/6 and CBA macrophages, before and after infection, differ greatly, both with respect to absolute number as well as cell function. Uninfected C57BL/6 macrophages express genes involved in the deactivation pathway of macrophages at lower levels, while genes related to the activation of the host immune inflammatory response, including apoptosis and phagocytosis, have elevated expression levels. Several genes that participate in the apoptosis process were also observed to be up-regulated in C57BL/6 macrophages infected with <it>L. amazonensis</it>, which is very likely related to the capacity of these cells to control parasite infection. By contrast, genes involved in lipid metabolism were found to be up-regulated in CBA macrophages in response to infection, which supports the notion that <it>L. amazonensis </it>probably modulates parasitophorous vacuoles in order to survive and multiply in host cells.</p> <p>Conclusion</p> <p>The transcriptomic profiles of C57BL/6 macrophages, before and after infection, were shown to be involved in the macrophage pathway of activation, which may aid in the control of <it>L. amazonensis </it>infection, in contrast to the profiles of CBA cells.</p

    Interference with Hemozoin Formation Represents an Important Mechanism of Schistosomicidal Action of Antimalarial Quinoline Methanols

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    Heme is an essential molecule to most living organisms, but once in a free state it exerts toxic effects. Blood-feeding organisms evolved efficient ways to detoxify free heme derived from hemoglobin digestion. A key mechanism present in some hematophagous organisms consists of the crystallization of heme into a pigment named hemozoin. Schistosoma mansoni is one of the etiologic agents of human schistosomiasis, a parasitic disease that affects over 200 million people in tropical and subtropical areas. Hemozoin formation represents the main heme detoxification pathway in S. mansoni. Here, we report that the antimalarial quinoline methanols quinine and quinidine exert schistosomicidal effects notably due to their capacity to interfere with hemozoin formation. When quinine or quinidine were administered intraperitoneally during seven days to S. mansoni-infected mice (75 mg/kg/day), both worm and eggs burden were significantly reduced. Interestingly, hemozoin content in female worms was drastically affected after treatment with either compound. We also found that quinine caused important changes in the cellular organization of worm gastrodermis and increased expression of genes related to musculature, protein synthesis and repair mechanisms. Together, our results indicate that interference with hemozoin formation is a valid chemotherapeutic target for development of new schistosomicidal agents
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