Biocatalytic CO2 absorption and structural studies of carbonic anhydrase under industrially-relevant conditions

UIDB/50006/2020 IF/00505/2014/CP1224/CT0004The unprecedently high CO2 levels in the atmosphere evoke the urgent need for development of technologies for mitigation of its emissions. Among the alternatives, the biocatalytic route has been claimed as one of the most promising. In the present work, the carbonic anhydrase from bovine erythrocytes (BCA) was employed as a model enzyme for structural studies in an aqueous phase at alkaline pH, which is typical of large-scale absorption processes under operation. Circular dichroism (CD) analysis revealed a high enzymatic stability at pH 10 with a prominent decrease of the melting temperature above this value. The CO2 absorption capacity of the aqueous solutions were assessed by online monitoring of pressure decay in a stainless-steel cell, which indicated a better performance at pH 10 with a kinetic rate increase of up to 43%, as compared to non-biocatalytic conditions. Even low enzyme concentrations (0.2 mg g−1) proved to be sufficient to improve the overall CO2 capture process performance. The enzyme-enhanced approach of CO2 capture presents a high potential and should be further studied.publishersversionpublishe

Ideias educacionais para adiar o fim do mundo

This paper refers to the book by Ailton Krenak (2019), Ideas to postpone the end of the world. The work brings a present hope in the possibility of “postponement”. Extending time, postponing the end of the world, would allow us to envision the construction of social relations beyond capital. The educational ideas highlighted in this text have in common the principle of inserting educators and students in the reins of the pedagogical process, inquiring and defining their purposes, thus acting consciously on behalf of collective objectives. We think that only through a path in which we are genuinely builders of reality is there a possibility of postponing the end of the world. And so, fight so that, perhaps, this is just the end of the world ruled by capital and not the end of the human species.Este artículo hace referencia al libro de Ailton Krenak (2019), Ideas para posponer el fin del mundo. La obra trae una esperanza presente en la posibilidad de “aplazamiento”. Prolongar el tiempo, posponer el fin del mundo, permitiría vislumbrar la construcción de relaciones sociales más allá del capital. Las ideas educativas destacadas en este texto tienen en común el principio de insertar a educadores y educandos en las riendas del proceso pedagógico, indagando y definiendo sus fines, actuando así conscientemente en pro de objetivos colectivos. Pensamos que sólo a través de un camino en el que seamos genuinamente constructores de realidad existe la posibilidad de postergar el fin del mundo. Y así, luchar para que, quizás, este sea solo el fin del mundo gobernado por el capital y no el fin de la especie humana.Este texto faz referência ao livro de Ailton Krenak (2019), Ideias para adiar o fim do mundo. A obra traz uma esperança presente na possibilidade de “adiamento”. Estender o tempo, postergar o fim do mundo, nos permitiria vislumbrar a construção de relações sociais para além do capital. As ideias educacionais destacadas neste texto têm em comum o princípio de inserir educadores e educandos nas rédeas do processo pedagógico, indagando e definindo suas finalidades, agindo, desse modo, conscientemente em nome de objetivos coletivos. Pensamos que somente por um caminho em que sejamos genuinamente construtores da realidade há possibilidade de adiar o fim do mundo. E assim, lutar para que, quiçá, seja este apenas o fim do mundo regido pelo capital e, não, o da espécie humana

Hepatitis B virus: molecular genotypes and HBeAg serological status among HBV-infected patients in the southeast of Brazil

<p>Abstract</p> <p>Background</p> <p>Knowledge of HBV genotype is very important for clinical treatment. Studies have suggested possible pathogenic and therapeutic differences among HBV genotypes. The aim of this study was to determine HBV subtypes and genotypes in HBV-infected patients in our region (southeast Brazil) and to correlate results with clinical and histopathological data.</p> <p>Methods</p> <p>One hundred and thirty-nine HBsAg-positive patients were included in the study. All patients were anti-HCV and anti-HIV negative (64% male; mean age 42 ± 14.5 years; range 7-80 years; 84% Caucasian) and were followed up at the University Hospital. A method for genotyping and subtyping HBV by partial HBsAg gene sequencing with primers common to all known genotypes was used. The viral load was measured by Amplicor Monitor assay (Roche).</p> <p>Results</p> <p>HBV genotype A was the most prevalent (55%), while genotypes C, D and F were found in 3%, 38% and 4% of HBV-infected patients, respectively. Among the patients infected by genotype A, 18.3% (14/76) were African descendents and, among the patients infected by genotype D, 11.3% (6/53) were also African descendents. In the four patients infected with genotype C, 2 were Asian descendents and 2 were Caucasians. All (7) genotype F infected patients were Caucasians. Seventy percent of our HBsAg-positive patients were HBeAg negative (62% genotypes A; 26.2% D; 7.1% C and 4.7%F). The viral load of HBV-DNA was about 5 times higher in HBeAg-positive than in HBeAg-negative patients. About 40% of these patients had alanine aminotransferase of up to 1.5 times the normal level. The mean stage of fibrosis in genotype A patients (2.8) was significantly higher than the mean stage of fibrosis in genotype D patients (2.0) (P = 0.0179).</p> <p>Conclusion</p> <p>The genotypes encountered in our HBV-infected patients were apparently a consequence of the types of immigration that occurred in our region, where European and African descendents predominate. The HBeAg-negative status predominated, possibly due to the length of time of infection. The viral load in HBeAg-positive patients was higher than in HBeAg-negative individuals. The fibrosis grade in genotype A-infected patients was more advanced than genotype D-infected patients.</p