23 research outputs found

    Normas e protocolos de biossegurança na clínica odontológica

    Get PDF
    Aprovado por unanimidade em Reunião Colegiada do ODT, no. 06/2015, em 07 de agosto de 2015.Este manual tem por objetivo apresentar protocolos e rotinas para tornar as atividades clínicas e laboratoriais mais seguras e organizadas para um melhor rendimento e qualidade do estudante da odontologia e futuro cirurgião-dentista

    Fast and low-cost synthesis of MoS2 nanostructures on paper substrates for near-infrared photodetectors

    Get PDF
    Recent advances in the production and development of two-dimensional transition metal dichalcogenides (2D TMDs) allow applications of these materials, with a structure similar to that of graphene, in a series of devices as promising technologies for optoelectronic applications. In this work, molybdenum disulfide (MoS2) nanostructures were grown directly on paper substrates through a microwave-assisted hydrothermal synthesis. The synthesized samples were subjected to morphological, structural, and optical analysis, using techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman. The variation of synthesis parameters, as temperature and synthesis time, allowed the manipulation of these nanostructures during the growth process, with alteration of the metallic (1T) and semiconductor (2H) phases. By using this synthesis method, two-dimensional MoS2 nanostructures were directly grown on paper substrates. The MoS2 nanostructures were used as the active layer, to produce low-cost near-infrared photodetectors. The set of results indicates that the interdigital MoS2 photodetector with the best characteristics (responsivity of 290 mA/W, detectivity of 1.8 × 109 Jones and external quantum efficiency of 37%) was obtained using photoactive MoS2 nanosheets synthesized at 200◦C for 120 min.publishersversionpublishe

    Modulation of the pharmacological effects of enzymatically-active PLA2 by BTL-2, an isolectin isolated from the Bryothamnion triquetrum red alga

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>An interaction between lectins from marine algae and PLA<sub>2 </sub>from rattlesnake was suggested some years ago. We, herein, studied the effects elicited by a small isolectin (BTL-2), isolated from <it>Bryothamnion triquetrum</it>, on the pharmacological and biological activities of a PLA<sub>2 </sub>isolated from rattlesnake venom (<it>Crotalus durissus cascavella</it>), to better understand the enzymatic and pharmacological mechanisms of the PLA<sub>2 </sub>and its complex.</p> <p>Results</p> <p>This PLA<sub>2 </sub>consisted of 122 amino acids (approximate molecular mass of 14 kDa), its pI was estimated to be 8.3, and its amino acid sequence shared a high degree of similarity with that of other neurotoxic and enzymatically-active PLA<sub>2</sub>s. BTL-2 had a molecular mass estimated in approximately 9 kDa and was characterized as a basic protein. In addition, BTL-2 did not exhibit any enzymatic activity.</p> <p>The PLA<sub>2 </sub>and BTL-2 formed a stable heterodimer with a molecular mass of approximately 24–26 kDa, estimated by molecular exclusion HPLC. In the presence of BTL-2, we observed a significant increase in PLA<sub>2 </sub>activity, 23% higher than that of PLA<sub>2 </sub>alone. BTL-2 demonstrated an inhibition of 98% in the growth of the Gram-positive bacterial strain, <it>Clavibacter michiganensis michiganensis </it>(Cmm), but only 9.8% inhibition of the Gram-negative bacterial strain, <it>Xanthomonas axonopodis </it>pv <it>passiflorae </it>(Xap). PLA<sub>2 </sub>decreased bacterial growth by 27.3% and 98.5% for Xap and Cmm, respectively, while incubating these two proteins with PLA<sub>2</sub>-BTL-2 inhibited their growths by 36.2% for Xap and 98.5% for Cmm.</p> <p>PLA<sub>2 </sub>significantly induced platelet aggregation in washed platelets, whereas BTL-2 did not induce significant platelet aggregation in any assay. However, BTL-2 significantly inhibited platelet aggregation induced by PLA<sub>2</sub>. In addition, PLA<sub>2 </sub>exhibited strong oedematogenic activity, which was decreased in the presence of BTL-2. BTL-2 alone did not induce oedema and did not decrease or abolish the oedema induced by the 48/80 compound.</p> <p>Conclusion</p> <p>The unexpected results observed for the PLA<sub>2</sub>-BTL-2 complex strongly suggest that the pharmacological activity of this PLA<sub>2 </sub>is not solely dependent on the presence of enzymatic activity, and that other pharmacological regions may also be involved. In addition, we describe for the first time an interaction between two different molecules, which form a stable complex with significant changes in their original biological action. This opens new possibilities for understanding the function and action of crude venom, an extremely complex mixture of different molecules.</p

    Pervasive gaps in Amazonian ecological research

    Get PDF

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Desenvolvimento e avaliação de fluxímetros termoelétricos para medidas de fluxo de calor

    No full text
    O presente trabalho, realizado no Laboratório de Instrumentação do Departamento de Física da UFV, consistiu no desenvolvimento de fluxímetros termoelétricos de boa precisão e baixo custo. Os fluxímetros desenvolvidos, que têm como sensores termopilhas obtidas por eletrodeposição, foram calibrados, usando-se uma metodologia de calibração simples e eficiente. Foram determinados também os tempos de resposta dos mesmos. Os fluxímetros foram testados, em campo, no experimento micrometeorológico realizado no Centro Experimental Aramar (CEA), em Iperó, SP, de 11 a 22 de março de 1991, coordenado pelo Departamento de Ciências Atmosféricas do Instituto Astronômico e Geofísico da USP. Foram feitas medidas de condutividade térmica para diversos tipos de solo, inclusive em função do seu teor de umidade, com a finalidade de se poder quantificar as perturbações ocasionadas pela diferença de condutividade térmica do sensor e do meio onde ele está inserido.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

    Oligodramnia sem rotura das membranas amnióticas: resultados perinatais

    No full text
    OBJETIVO: avaliar os resultados perinatais em casos de oligodramnia sem rotura de membranas amnióticas. MÉTODOS: foram estudados retrospectivamente 51 casos consecutivos de oligodramnia (índice de líquido amniótico (ILA) menor que 5 cm) em nascimentos ocorridos no período de março de 1998 a setembro de 2001. Compararam-se os dados obtidos aos de 61 casos com quantidade intermediária e normal de líquido amniótico (ILA >5 cm). Analisaram-se variáveis maternas e neonatais, bem como taxas de mortalidade fetal, neonatal precoce e perinatal. As avaliações estatísticas foram realizadas mediante a aplicação do teste não paramétrico do c² com a correção de Yates, e do teste t de Student. Adotou-se o nível de significância de 5%. RESULTADOS: não houve diferença significante entre os grupos estudados, ao se analisar a ocorrência de síndrome hipertensiva, presença de mecônio, índice de Apgar inferior a sete no primeiro e quinto minuto, internação na unidade de tratamento intensivo neonatal e prematuridade. A oligodramnia associou-se significantemente ao tipo de parto (p<0,0002; RR=0,32), sofrimento fetal agudo (p<0,0004; RR=2,2) e presença de malformações fetais (p<0,01; RR=5,4). Os percentuais de malformações fetais foram de 17,6 e 3,3% nos grupos de oligodramnia e normal, respectivamente. As taxas de mortalidade fetal (2,0 vs 1,6%), neonatal (5,9 vs 1,6%) e perinatal (7,8 vs 3,3%), em ambos os grupos, não apresentaram diferença significante. CONCLUSÃO: a oligodramnia se associou a um aumento do risco para operação cesariana, sofrimento fetal agudo e malformações fetais
    corecore