29 research outputs found

    The role of backstop shape during inversion tectonics physical models.

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    O estilo da deforma??o de sequ?ncias sedimentares de bacias submetidas a uma invers?o tect?nica positiva foi discutido a partir da an?lise de modelos laboratoriais, desenvolvidos em caixas de experimentos, com camadas de areia depositadas no espa?o entre dois blocos de madeira. O espa?o simulava est?gios de extens?o crustal que conduziram ? forma??o de (1) um hemi-graben, gerado sobre um descolamento basal l?strico, com os blocos simulando o teto e o muro; e (2) um graben, com os blocos representando as margens externas que se distanciaram ao longo de um descolamento horizontal. Combina??es de dois angulos diferentes foram usadas para simular o mergulho das falhas normais curvas ao longo da face interna dos blocos de madeira. Nos hemi-grabens, os anteparos possu?am geometria convexa, e, nos grabens, geometria c?ncava. No pacote de areia, o encurtamento foi particionado em movimentos dirigidos a p?s e antepa?s, e a cinem?tica da contra??o foi fortemente influenciada pela geometria convexa ou c?ncava das faces internas dos anteparos. Um efeito obst?culo, caracterizado por rota??o do pacote de areia, pr?ximo ao bloco do muro, foi mais elevado junto ?s faces internas dos blocos de mais alto angulo de mergulho. Os resultados foram comparados a outros experimentos f?sicos e aplicados a uma bacia invertida encontrada na natureza.The style of deformation of rocks from basin-infilling sequences in positively inverted natural basins was discussed upon the results of laboratory experiments carried out in sandboxes with sand packs laid down in the space between two wooden blocks. The space simulated stages of crustal extension leading to (1) a half graben due to extension above a listric extensional detachment, with the blocks simulating the footwall and hanging wall, or (2) a graben, with the blocks simulating the external margins that drifted apart above a horizontal detachment. Combinations of two diferente angles were used to simulate the dip of curved normal faults along the internal face of the wooden blocks. Backstops in the half graben had a convex up internal face. Backstops in the graben had a concave up internal face. Shortening was partitioned in forward and backward movements within the sand packs, and the kinematics of contraction was largely influenced by the convex or concave internal faces. A buttress effect characterized by rotation of the sand pack close to the footwall was stronger for footwall with steeper-dipping internal faces. The results were compared to other physical experiments and applied to an inverted basin found in nature

    Sensor Surface Design with NanoMaterials: A New Platform in the Diagnosis of COVID-19

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    Mass testing for COVID-19 is essential to defining patient management strategies, choosing the best clinical management, and dimensioning strategies for controlling viral dissemination and immunization strategies. Thus, it is of utmost importance to search for devices that allow a quick and reliable diagnosis of low cost that can be transposed from the bench to the bedside, such as biosensors. These devices can help choose the correct clinical management to minimize factors that lead to infected patients developing more severe diseases. The use of nanomaterials to modify biosensors’ surfaces to increase these devices’ sensitivity and their biofunctionality enables high-quality nanotechnological platforms. In addition to the diagnostic benefits, nanotechnological platforms that facilitate the monitoring of anti-SARS-CoV-2 antibodies may be the key to determining loss of protective immune response after an episode of COVID-19, which leads to a possible chance of reinfection, as well as how they can be used to assess and monitor the success of immunization strategies, which are beginning to be administered on a large scale and that the extent and duration of their protection will need to be determined. Therefore, in this chapter, we will cover nanomaterials’ use and their functionalities in the surface design of sensors, thus generating nanotechnological platforms in the various facets of the diagnosis of COVID-19

    Post-acute COVID-19 syndrome after reinfection and vaccine breakthrough by the SARS-CoV-2 Gamma variant in Brazil.

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    We describe a case of prolonged COVID-19 caused by the SARS-CoV-2 Gamma variant in a fully vaccinated healthcare worker, 387 days after an infection caused by lineage B.1.1.33. Infections were confirmed by whole-genome sequencing and corroborated by the detection of neutralizing antibodies in convalescent serum samples. Considering the permanent exposure of this healthcare worker to SARS-CoV-2, the waning immunity after the first infection, the low efficacy of the inactivated vaccine at preventing COVID-19, the immune escape of the Gamma variant (VOC), and the burden of post-COVID syndrome, this individual would have benefited from an additional dose of a heterologous vaccine

    Photoluminescence and Magnetism in Mn2+-Doped ZnO Nanostructures Grown Rapidly by the Microwave Hydrothermal Method

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    Zn1-xMnxO nanostructures were synthesized via the microwave-assisted hydrothermal method, which rapidly produces particles of controlled size and morphology. Samples were analyzed considering the effects of manganese ion concentration. XRD revealed that all samples had wurtzite-type structure with Mn2+ ions incorporated in the oxide lattice. UV-vis spectra showed absorption bands from the d-d transitions of Mn2+ ions. As the doping concentration increased, the value of the energy gap decreased, indicating intermediary energy levels within the band gap in the Mn-doped ZnO samples. All samples produced broadband photoluminescence (PL) emissions in the yellow-orange-red range. Additionally, the PL intensity decreased with Mn2+ ion incorporation into the ZnO lattice due to the creation of new recombination centers. Microscopy images showed that manganese in the ZnO matrix produced homogeneously distributed nanostructures. EPR results indicated two locations of Mn2+ ions in the ZnO lattice, lower concentrations in the core of the lattice and higher concentrations at the surface.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Rede Nanobiotec/BrasilRede Mineira de Quimica (RQ:MG)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ Fed Uberlandia, Inst Quim, BR-38400902 Uberlandia, MG, BrazilUniv Fed Uberlandia, Inst Fis, LNMIS, BR-38400902 Uberlandia, MG, BrazilUniversidade Federal de São Paulo, Dept Ciencias Mar, BR-11030400 Santos, BrazilUniversidade Federal de São Paulo, Dept Ciencias Mar, BR-11030400 Santos, BrazilCNPq: 477150/2008-0FAPEMIG: APQ-01842-09Web of Scienc

    Torque, myoeletric sygnal and heart rate responses during concentric and eccentric exercises in older men

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    Background: The literature reports that the eccentric muscular action produces greater force and lower myoelectric activity than the concentric muscular action, while the heart rate (HR) responses are bigger during concentric contraction. Objectives: To investigate the maximum average torque (MAT), surface electromyographic (SEMG) and the heart rate (HR) responses during different types of muscular contraction and angular velocities in older men. Methods: Twelve healthy men (61.7 +/- 1.6years) performed concentric (C) and eccentric (E) isokinetic knee extension-flexion at 60 degrees/s and 120 degrees/s. SEMG activity was recorded from vastus lateralis muscle and normalized by Root Mean Square-RMS (mu V) of maximal isometric knee extension at 60 degrees. HR (beats/min) and was recorded at rest and throughout each contraction. The data were analyzed by the Friedman test for repeated measures with post hoc Dunn's test (p<0.05). Results: The median values of MAT (N.m/kg) was smaller and the RMS (mu V) was larger during concentric contraction (C60 degrees/s=2.80 and 0.99; C120 degrees/s=2.46 and 1.0) than eccentric (E60 degrees/s=3.94 and 0.85; E120 degrees/s=4.08 and 0.89), respectively. The HR variation was similar in the four conditions studied. Conclusion: The magnitude of MAT and RMS responses in older men were dependent of the nature of the muscular action and independent of the angular velocity, whereas HR response was not influenced by these factors.CONTEXTUALIZAÇÃO: A literatura refere que a ação muscular excêntrica produz maior força e menor atividade mioelétrica que a concêntrica, enquanto a resposta da frequência cardíaca (FC) é maior durante a contração concêntrica que durante a excêntrica. OBJETIVOS: Investigar as respostas de torque médio máximo (TMM), eletromiografia de superfície (EMGs) e FC durante diferentes tipos de contração muscular e velocidades angulares em homens idosos. MATERIAIS E MÉTODOS: Doze homens saudáveis (61,7±1,6 anos) realizaram flexões e extensões do joelho concêntrica (C) e excêntrica (E) em 60º/s e 120º/s. Registrou-se a atividade EMGs do músculo vasto lateral e normalizou-se pela RMS (µV) da extensão isométrica máxima do joelho em 60º. A FC (bpm) foi registrada em repouso e durante cada contração. Os dados foram analisados utilizando-se o teste de Friedman para medidas repetidas com post hoc de Dunn (p<0,05). RESULTADOS: Os valores médios de TMM (N.m/kg) foram menores e os de RMS (µV) foram maiores (p<0,05) nas contrações concêntricas (C60º/s=2,80 e 0,99; C120º/s=2,46 e 1,0) comparativamente com as excêntricas (E60º/s=3,94 e 0,85; E120º/s=4,08 e 0,89), respectivamente. Já a variação da FC foi semelhante nas quatro condições estudadas. CONCLUSÃO: A magnitude das respostas de TMM e RMS em homens idosos foi dependente da natureza da ação muscular e independente da velocidade angular, enquanto as respostas da FC não foram influenciadas por esses fatores
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