Simulation of microalgal growth in a continuous photobioreactor with sedimentation and partial biomass recycling

Microalgae are considered as promising feedstocks for the third generation of biofuels. They are autotrophic organisms with high growth rate and can stock an enormous quantity of lipids (about 20 \u2013 40% of their dried cellular weight). This work was aimed at studying the cultivation of Scenedesmus obliquus in a two-stage system composed of a photobioreactor and a settler to concentrate and partially recycle the biomass as a way to enhance the microalgae cellular productivity. It was attempted to specify by simulation and experimental data a relationship between the recycling rate, kinetic parameters of microalgal growth and photobioreactor operating conditions. Scenedesmus obliquus cells were cultivated in a lab-scale flat-plate reactor, homogenized by aeration, and running in continuous flow with a residence time of 1.66 day. Experimental data for the microalgal growth were used in a semi-empirical simulation model. The best results were obtained for Fw = 0.2FI , when R = 1 and kd = 0 and 0.05 day-1, with the biomass production in the reactor varying between 8 g L -1 and 14 g L-1, respectively. The mathematical model fitted to the microalgal growth experimental data was appropriate for predicting the efficiency of the reactor in producing Scenedesmus obliquus cells, establishing a relation between cellular productivity and the minimum recycling rate that must be used in the system

Determinant factors in an expressive increasing of liver transplant in a single center

INTRODUÇÃO: O Hospital das Clinicas da Universidade de São Paulo é o maior hospital do Brasil. Seu programa de transplante foi o pioneiro neste país e realizou seu primeiro transplante de fígado em 1968. A lista de espera para transplante de fígado tem cerca de 700 pacientes, e ultrapassou mil há alguns anos. Apesar deste fato, nosso numero de transplantes de fígado não era muito elevado (cerca de 50/ano) e tínhamos, como esperado, alta mortalidade na lista de espera. Este ano aumentamos significativamente o numero de transplantes de fígado, atingindo 3 vezes a média dos últimos anos. OBJETIVO: Nosso objetivo é explicitar os fatores determinantes neste aumento expressivo do numero de transplantes de fígado em um único centro no Brasil. MÉTODOS: Analisamos o numero de transplantes de fígado no mesmo período do ano (de janeiro a setembro) em 2008 e 2009 no Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo. Foram avaliadas as razões deste aumento de transplantes de fígado em 2009 neste centro. RESULTADOS: Comparando o período de janeiro a setembro de 2008 com o mesmo período de 2009, o número de transplantes de fígado aumentou em 200% (35 para 105). A imprensa, o sistema de saúde pública, a organização da equipe transplantadora, a internação de pacientes críticos, o preparo pré-operatório, a aceitação de doadores com critérios expandidos, o programa de doadores vivos, e os fígados bipartidos foram determinantes neste aumento de transplantes de fígado nesta instituição. A sobrevida atuarial melhorou com o aumento do número de transplantes (75% para 85%). CONCLUSÃO: Ainda é possível aumentar o número de transplantes de fígado em países em desenvolvimento. O mecanismo desta transformação é multifatorial e necessita de esforço do governo, institucional e multidisciplinar. Apesar do uso de fígados marginais e bipartidos, o aumento do número de transplantes está relacionado a melhor resultado.INTRODUCTION: The Clinical Hospital of Sao Paulo University is the biggest hospital of Brazil. Its transplant program was the pioneer in this country and it performed its first liver transplant in 1968. The adult waiting list for liver transplant has about 700 patients nowadays, and it has had more than a thousand some years ago. Even though, our number of liver transplants was not so high (about 50 a year) and we had, as expected, high waiting list mortality. This year we raised significantly our liver transplant number, increasing in 3 times our past few years’ average. AIM: We would like to highlight the determinant factors in this expressive increasing number of liver transplants in a single center in Brazil. METHODS: We analyzed the number of liver transplants in the same period of the year (from January to September) in 2008 and 2009 at the Clinical Hospital of Sao Paulo University Medical School. It was evaluated the reasons of the increasing rate of liver transplants in 2009 at this center. RESULTS: Comparing the period from January to September 2008 with the same period of 2009, the liver transplant number increased 200% (35 to 105) .Mass media, public health system policy, transplant team organization, hospitalization of critical patients, preoperative prepare, acceptance of expanded criteria donors, living donor program, and split livers were determinant in this raising of liver transplants at this institution. The actuarial survival rate improved with the increasing number of liver transplants (75% to 85%). CONCLUSION: It is still possible to increase the number of liver transplants in developing countries. The mechanism of such change is multifactorial and it needs government, institutional and multidisciplinary efforts. Besides the use of marginal and split livers, the increasing rate of transplants is related to better outcome

Bioethanol from Microalgal Biomass: A Promising Approach in Biorefinery

Abstract The development of new technologies which increase the production of biofuel without directly compete with food production is required. Microalgal biomass has recently been in the highlight. The role of this biomass is here discussed within the concept of biorefinery and industrial sustainability of bioethanol production. The process of cultivation in order to accumulate around 50% of carbohydrates in the biomass (dry weight) and the importance of water and nutrient recycling are reviewed. Saccharification of biomass using enzymes or acids and alternative processes such as hydrothermal liquefaction and flash hydrolysis are addressed. Since the main monosaccharide in microalgal biomass is glucose, high rates of hydrolysis and fermentation were, generally, achieved (more than 80% of the efficiency as a sum of these two processes). Anaerobic digestion to treat vinasse and the recycling of CO2 from the ethanolic fermentation and biogas could increase the process sustainability. Alternative techniques for the concentration of bioethanol from fermentation broth and for the optimization of fuel transportation are mentioned. Finally, the advantage of using microalgae rather than other sources is estimated with reference to the production rate, even though the cultivation costs are still high

When the voices are multiple

Interview with Prof. Juan-Carlos Molleda, University of OregonInterview with Prof. Juan-Carlos Molleda, University of OregonInterview with Prof. Juan-Carlos Molleda, University of Orego

Expressões naturais, artificialismo e indivíduos especiais

Orientadora : Leila Juliette KalóMonografia (especialização) - Universidade Federal do Paraná, Setor de Educação, Curso de Especialização em Educação Especial.Inclui referências

Parece un teorema, pero solo es una distracción

CHARAUDEAU, P. A conquista da opinião pública – como o discurso manipula as escolhas políticas. Trad. Angela M. S. Corrêa. São Paulo: Contexto, 2020.Resenha de CHARAUDEAU, P. A conquista da opinião pública – como o discurso manipula as escolhas políticas. Trad. Angela M. S. Corrêa. São Paulo: Contexto, 2020.Resenha de CHARAUDEAU, P. A conquista da opinião pública – como o discurso manipula as escolhas políticas. Trad. Angela M. S. Corrêa. São Paulo: Contexto, 2020

Miradas en perspectiva sobre la comunicación organizacional

Resenha do Livro: Comunicação organizacional: dimensões epistemológicas e discursivasAutoras: Ângela Cristina Salgueiro Marques; Ivone de Lourdes Oliveira (Org.)Resenha do Livro: Comunicação organizacional: dimensões epistemológicas e discursivasAutoras: Ângela Cristina Salgueiro Marques; Ivone de Lourdes Oliveira (Org.