Na,K -ATPase containing the amino acid substitution glutamate to alanine at position 779 of the α... more Na,K -ATPase containing the amino acid substitution glutamate to alanine at position 779 of the α subunit (Glu779Ala) supports a high level of Na-ATPase and electrogenic Na+–Na+ exchange activityin the absence of K +. In microsomal preparations of Glu779Ala enzyme, the Na+ concentration for half maximal activation of Na-ATPase activity was 161 ± 14 mM (n = 3). Furthermore, enzyme activity with 800 mM Na+ was found to be similar in the presence and absence of 20 mM K +. These results showed that Na+, with low affinity, could stimulate enzyme turnover as effectively as K +. To gain further insight into the mechanism of this enzyme activity, HeLa cells expressing Glu779Ala enzyme were voltage clamped with patch electrodes containing 115 mM Na+ during superfusion in K +-free solutions. Electrogenic Na+–Na+ exchange was observed as an ouabain-inhibitable outward current whose amplitude was proportional to extracellular Na+ (Na+o) concentration. At all Na+o concentrations tested (3–148 mM...
O súbito aumento da demanda por higienizantes e sanitizantes, ocasionado pela pandemia de COVID-1... more O súbito aumento da demanda por higienizantes e sanitizantes, ocasionado pela pandemia de COVID-19, desencadeou um crescente aumento no número de empresas produtoras de sanitizantes para as mãos, principalmente, álcool em gel. Dificuldades na elaboração, desenvolvimento e operação do processo produtivo, aliado à insegurança dos colaboradores no desempenho de suas atividades podem ser desafios que interferem na capacidade destes empreendimentos em produzir processos, produtos e um ambiente de trabalho de qualidade. Dentro deste contexto, os sistemas de saúde e segurança do trabalho podem desempenhar um papel fundamental no posicionamento estratégico e no desenvolvimento sustentável de uma empresa, além de contribuir para motivação e bem estar de seus colaboradores, gerando bons resultados e competitividade. Este trabalho teve como objetivo elaborar diretrizes para implantação de um sistema de saúde e segurança do trabalho voltado para o processo produtivo de álcool em gel e para o ma...
Polyurethane is a class of polymer that presents as main feature the versatility in its physical ... more Polyurethane is a class of polymer that presents as main feature the versatility in its physical and chemical properties. Knowing the kinetic parameters of the thermal degradation of these materials collaborates with the development of new applications. Therefore, this work had as objective to s tudy of the kinetic parameters of the thermal decomposition of vegetable oil-based polyurethane (castor oil), through non - isothermal thermogravimetric method. The thermogravimetric curves of the samples showed two decomposition steps, and the kinetic parameters of each step were determined using the Flynn-Wall-Ozawa (FWO) method. The first stage of thermal decomposition presents characteristics of first-order reactions, the second stage of decomposition presented a behavior similar to that of the first stage until α equal to 0.4, in the conversion range between 0.4 and 0.9 a concave profile was observed, characteristic of complex processes, indicating parallel reactions and minimum lifetime of 1650 years old.
Na,K -ATPase containing the amino acid substitution glutamate to alanine at position 779 of the α... more Na,K -ATPase containing the amino acid substitution glutamate to alanine at position 779 of the α subunit (Glu779Ala) supports a high level of Na-ATPase and electrogenic Na+–Na+ exchange activityin the absence of K +. In microsomal preparations of Glu779Ala enzyme, the Na+ concentration for half maximal activation of Na-ATPase activity was 161 ± 14 mM (n = 3). Furthermore, enzyme activity with 800 mM Na+ was found to be similar in the presence and absence of 20 mM K +. These results showed that Na+, with low affinity, could stimulate enzyme turnover as effectively as K +. To gain further insight into the mechanism of this enzyme activity, HeLa cells expressing Glu779Ala enzyme were voltage clamped with patch electrodes containing 115 mM Na+ during superfusion in K +-free solutions. Electrogenic Na+–Na+ exchange was observed as an ouabain-inhibitable outward current whose amplitude was proportional to extracellular Na+ (Na+o) concentration. At all Na+o concentrations tested (3–148 mM...
O súbito aumento da demanda por higienizantes e sanitizantes, ocasionado pela pandemia de COVID-1... more O súbito aumento da demanda por higienizantes e sanitizantes, ocasionado pela pandemia de COVID-19, desencadeou um crescente aumento no número de empresas produtoras de sanitizantes para as mãos, principalmente, álcool em gel. Dificuldades na elaboração, desenvolvimento e operação do processo produtivo, aliado à insegurança dos colaboradores no desempenho de suas atividades podem ser desafios que interferem na capacidade destes empreendimentos em produzir processos, produtos e um ambiente de trabalho de qualidade. Dentro deste contexto, os sistemas de saúde e segurança do trabalho podem desempenhar um papel fundamental no posicionamento estratégico e no desenvolvimento sustentável de uma empresa, além de contribuir para motivação e bem estar de seus colaboradores, gerando bons resultados e competitividade. Este trabalho teve como objetivo elaborar diretrizes para implantação de um sistema de saúde e segurança do trabalho voltado para o processo produtivo de álcool em gel e para o ma...
Polyurethane is a class of polymer that presents as main feature the versatility in its physical ... more Polyurethane is a class of polymer that presents as main feature the versatility in its physical and chemical properties. Knowing the kinetic parameters of the thermal degradation of these materials collaborates with the development of new applications. Therefore, this work had as objective to s tudy of the kinetic parameters of the thermal decomposition of vegetable oil-based polyurethane (castor oil), through non - isothermal thermogravimetric method. The thermogravimetric curves of the samples showed two decomposition steps, and the kinetic parameters of each step were determined using the Flynn-Wall-Ozawa (FWO) method. The first stage of thermal decomposition presents characteristics of first-order reactions, the second stage of decomposition presented a behavior similar to that of the first stage until α equal to 0.4, in the conversion range between 0.4 and 0.9 a concave profile was observed, characteristic of complex processes, indicating parallel reactions and minimum lifetime of 1650 years old.
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