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Search Results: 1 - 10 of 6478 matches for " Gilvan Caetano Duarte "
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Use of Residual Biomass from the Textile Industry as Carbon Source for Production of a Low-Molecular-Weight Xylanase from Aspergillus oryzae
Gilvan Caetano Duarte,Leonora Rios de Souza Moreira,Diana Paola Gómez-Mendoza,Félix Gon?alves de Siqueira,Luís Roberto Batista,Lourdes Isabel Velho do Amaral,Carlos André Ornelas Ricart,Edivaldo Ximenes Ferreira Filho
Applied Sciences , 2012, DOI: 10.3390/app2040754
Abstract: Pretreated dirty cotton residue (PDCR) from the textile industry was used as an alternative carbon source for the submerged cultivation of Aspergillus oryzae and the production of xylanases. The filtered culture supernatant was fractionated by ultrafiltration followed by three chromatographic steps, which resulted in the isolation of a homogeneous low-molecular-weight xylanase (Xyl-O1) with a mass of 21.5 kDa as determined by sodium dodecyl sulfate-polyacrilamide gel electrophoresis (SDS-PAGE) co-polymerized with 0.1% oat spelt xylan. Enzyme catalysis was the most efficient at 50 °C and pH 6.0. The K m values (mg·mL ?1) for the soluble fraction of oat spelt and birchwood xylans were 10.05 and 3.34, respectively. Xyl-O1 was more stable in the presence of 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB), 1,4-dithiothreitol (DTT), l-cysteine or β-mercaptoethanol, which increased the rate of catalysis by 40%, 14%, 40% or 37%, respectively. The enzyme stability was improved at pH 7.0 in the presence of 20 mM l-cysteine, with the retention of nearly 100% of the activity after 6 h at 50 °C. Xyl-O1 catalyzed the cleavage of internal β-1,4 linkages of the soluble substrates containing d-xylose residues, with a maximum efficiency of 33% for the hydrolysis of birchwood xylan after 12 h of incubation. Identification of the hydrolysis products by high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) indicated the predominance of the hydrolysis products X2-X6 during the first 12 h of incubation and the accumulation of higher xylooligomers after the elution of the last xylooligomer standard, xylohexaose.
An Acidic Thermostable Recombinant Aspergillus nidulans Endoglucanase Is Active towards Distinct Agriculture Residues
Eveline Queiroz de Pinho Tavares,Marciano Regis Rubini,Thiago Machado Mello-de-Sousa,Gilvan Caetano Duarte,Fabrícia Paula de Faria,Edivaldo Ximenes Ferreira Filho,Cynthia Maria Kyaw,Ildinete Silva-Pereira,Marcio Jose Po?as-Fonseca
Enzyme Research , 2013, DOI: 10.1155/2013/287343
Abstract: Aspergillus nidulans is poorly exploited as a source of enzymes for lignocellulosic residues degradation for biotechnological purposes. This work describes the A. nidulans Endoglucanase A heterologous expression in Pichia pastoris, the purification and biochemical characterization of the recombinant enzyme. Active recombinant endoglucanase A (rEG A) was efficiently secreted as a 35?kDa protein which was purified through a two-step chromatography procedure. The highest enzyme activity was detected at C/pH 4. rEG A retained 100% of activity when incubated at 45 and C for 72?h. Purified rEG A kinetic parameters towards CMC were determined as ?mg/mL, ?mmol/min, and 55.8?IU (international units)/mg specific activity. Recombinant P. pastoris supernatant presented hydrolytic activity towards lignocellulosic residues such as banana stalk, sugarcane bagasse, soybean residues, and corn straw. These data indicate that rEG A is suitable for plant biomass conversion into products of commercial importance, such as second-generation fuel ethanol. 1. Introduction One of the major challenges of modern society is to promote economic growth in a sustainable model. Global demands of energy consumption stimulate the research on alternative fuels, aiming the reduction of the dependence on nonrenewable energy sources. For some decades now, Brazil and the USA have successfully produced bioethanol from sugarcane and corn, respectively. Nonetheless, plant biomass generated by extensive cultures, and which is not totally converted into useful by-products such as fertilizers and animal feed, tends to accumulate and cause environmental problems. Numerous efforts have been made in order to develop biotechnological routes to produce the so-called second-generation bioethanol from agriculture residues such as corn stover, rice straw, sorghum bagasse, corncobs, wheat bran, wheat straw, and sugarcane bagasse. The limiting step of this process is the availability of low-cost efficient enzymes to convert lignocellulose into fermentable glucose units. Filamentous fungi can produce and secrete enzymes which efficiently degrade cellulose, a linear polymer of glucopyranose units connected by β-1,4 bonds, to oligosaccharides and glucose. Based on model organisms from the genera Trichoderma and Phanerochaete, fungi cellulolytic enzymes acting in synergism have been classified as (1) endoglucanases or endo-β-1,4-glucanases (EC 3.2.1.4), responsible for the random attack of internal glycosidic bonds of the cellulose amorphous region, generating oligosaccharides of various sizes and new chain ends
Incorporando a variabilidade no processo de identifica??o do modelo de máximo global no Grade of Membership (GoM): considera??es metodológicas
Guedes, Gilvan Ramalho;Siviero, Pamila Cristina Lima;Caetano, André Junqueira;Machado, Carla Jorge;Brondízio, Eduardo;
Revista Brasileira de Estudos de Popula??o , 2011, DOI: 10.1590/S0102-30982011000200006
Abstract: the availability of increasingly complex and multidimensional datasets is one of the main causes for the increase in studies employing multivariate analyses based on fuzzy sets. even though the grade of membership method has been widely used in brazil for empirical studies in health and social sciences, issues regarding identifiability and stability of the final parameters estimated by gom 3.4 software have not been thoroughly examined. given the relevance of unique and stable parameters, guedes et al. (2010) proposed an empirical method to locate a global maximum (gm) with stable parameters. however, the gm locator does not incorporate variability. in the present article, this limitation is circumvented by employing a weighted statistic - weight global maximum (wgm) - similar to the variation coefficient. this indicator does not affect disproportionately situations with very low mean deviations. the wgm locator is shown to decrease the distance of the identified model from the real structure, when compared with the gm locator.
Identificabilidade e estabilidade dos parametros no método Grade of Membership (GoM): considera??es metodológicas e práticas
Guedes, Gilvan Ramalho;Caetano, André Junqueira;Machado, Carla Jorge;Brondízio, Eduardo Sonewend;
Revista Brasileira de Estudos de Popula??o , 2010, DOI: 10.1590/S0102-30982010000100003
Abstract: the grade of membership (gom) method has been increasingly employed by brazilian demographers, and has the advantage of including a parameter that measures individual heterogeneousness on the basis of non-observable correlations among the categories of responses to variables of interest. the parameter shows each individual's degree of membership to extreme profiles. several authors, however, have called attention to important issues in adjusting the final models that use 3.4 version of the gom program, such as the problem of identifiability - multiple solutions for estimated parameters. in this article a procedure is discussed that is able to identify a final model with a single solution that describes the pure types that are the most reliable for the database, in an attempt at streamlining. to illustrate this process, a database was used with data corresponding to an economic and sociodemographic study of a population of small farmers living along the transamazon highway, in the northern state of pará, brazil. the existence of instability in the parameters estimated by the gom 3.4 program was also identified and a method of stabilization of its values was proposed. with these combined procedures, users of the gom 3.4 program will be able to describe their databases more adequately and respond to criticisms regarding the identifiability and stability of the resulting models. these empirical solutions are significant. not only do they affect calculations of prevalence and incidence of events of interest, they also bring about important consequences at the correct point and correct moment for interventions of public policies or of prospective planning in projection analyses.
The Forward Proton Detector at D0
Gilvan Alves
Physics , 1998,
Abstract: We present the first results of detector R & D done for the proposed Forward Proton Detector at D0. From a menu of options we have chosen a scintillating fiber based detector with multi-anode photomultiplier readout.
Influência do nível de for?a máxima na produ??o e manuten??o da potência muscular
Paulo, Anderson Caetano;Tavares, Lucas Duarte;Cardoso, Ronaldo Kobal;Lamas, Leonardo;Pivetti, Bruno;Tricoli, Valmor;
Revista Brasileira de Medicina do Esporte , 2010, DOI: 10.1590/S1517-86922010000600005
Abstract: it seems that stronger subjects present less strength endurance compared to weaker subjects at the same relative intensity. since the level of maximum strength affects power production, it is also expected that stronger subjects present lower power endurance. the aim of this study was to evaluate the effects of maximum strength on power production and endurance over multiple sets and repetitions of the half-squat exercise. forty- two subjects were classified according to the result in the 1rm test and the 10 strongest and 10 weakest were selected to participate. in order to evaluate power endurance, both groups performed 10 sets of 6 repetitions at 40% and 60% 1rm as fast as possible. the absolute power (ap) and relative power (rp) (corrected by body weight) developed in half-squat concentric phase were measured. analysis of variance for repeated measures (two-way anova) revealed that the stronger subjects decreased ap from 4th repetition on and rp from 5th repetition on at 60% 1rm. the weakest subjects decreased ap from 6th repetition on and maintained rp production over the ten series. there was no significant effect on 40% 1rm. this result suggests that stronger subjects fatigue first at higher intensities. the early fatigue in stronger subjects could be associated with different factors related to body control of homeostasis such as blood pressure, motor units recruitment and proportion of types i and ii muscle fibers.
Distribui??o e abundancia relativa de cumbaca Trachelyopterus striatulus Steindachner (Osteichthyes, Auchenipteridae) no reservatório de Lajes, Rio de Janeiro, Brasil
Duarte, Silvana;Caetano, Carla de Brito;Vicentini, Rafaela Nascimento;Araújo, Francisco Gerson;
Revista Brasileira de Zoologia , 2002, DOI: 10.1590/S0101-81752002000300029
Abstract: the catfish trachelyopterus striatulus steindachner, 1877 is a very abundant fish species in reservoirs in southeast brazil, and its relative abundance seems to be increasing in several lentic environments. despite of being a very common species, few information is available on its distribution and other aspects of ecology. the lajes reservoir (22o42'-22o50's e 43o53'-44o05'w) is the largest manmade lake for hydropower purposes in rio de janeiro state, where this species rank among the top abundant fishes, both in number and in biomass. its relative abundance were compared in three zones of the reservoir (upper, central and lower), based on a standardized program, during three annual periods (monthly sampling in 1994 and bi-monthly sampling in 1996 and 1997), with a total of three hundred twenty samples, using gill nets. environmental variables of water temperature, ph and transparency were taken in each sampling occasion, and information on rainfall and level of the water were recorded. trachelyopterus striatulus showed an increasing abundance during the study period, rising from fifty rank in 1994 to the most abundant fish in 1997, coinciding with decreasing water level, and suggesting that this species take advantage of the harsh conditions in the reservoir to increase population. highest number and weight were recorded in the upper zone, which presented the lowest transparency. seasonally no significance (p > 0,05) difference in abundance was found over the whole period.
Motor development of kindergarten in 13 months interval
Maria Joana Duarte Caetano,Carolina Rodrigues Alves Silveira,Lilian Teresa Bucken Gobbi
Revista Brasileira de Cineantropometria e Desempenho Humano , 2005,
Abstract: Motor development is a changing process of individual functioning level where a better capacity to control movements is acquiring with time. Then, the purpose of this study was to analyze the changes in children motor behavior in 13 months interval. Thirty-five children ranging from 3 to 7 years of age participated and were distributed in 4 age groups. The motor performance of each participant were evaluated and reevaluated after 13 months by means of the Motor Development Scale, which is a test battery with specific tasks according to the age for each component: fine skill, global skill, balance, body schema/fastness, and spatial organization. Motor performance was compared inter and intra groups for each component. The results showed that the motor performance in the balance tasks improved after the 13 months for all age groups; for fine skill, global skill, and body schema children of 3, 4, and 5 years of age improved their performances between the evaluations; for spatial organization only children of 3 and 5 years of age improved their performances when reevaluated. These results suggest that the development in this age range occurs in a no homogeneous way, i.e., it presents different rhythms for the motor components. Environmental, individual and task factors can explain the developmental changes in a 13 months period. We conclude that the developmental process of each motor component is dynamic and it presents no linearity aspects. RESUMO O desenvolvimento motor é um processo de mudan as no nível de funcionamento de um indivíduo, onde uma maior capacidade de controlar movimentos é adquirida ao longo do tempo. Assim, o objetivo principal deste estudo foi analisar as mudan as no comportamento motor de crian as no intervalo de 13 meses. Participaram deste estudo 35 crian as entre 3 e 7 anos de idade distribuídas por faixa etária em 4 grupos. O desempenho motor de cada participante foi avaliado e re-avaliado após 13 meses por meio da Escala de Desenvolvimento Motor, que compreende uma bateria de testes envolvendo tarefas específicas por idade nos itens motricidade fina, motricidade global, equilíbrio, esquema corporal/rapidez e organiza o espacial. Foram realizadas compara es do desempenho motor intra e entre os grupos, para cada item da bateria. Os resultados mostraram que o desempenho motor nas tarefas de equilíbrio melhorou após 13 meses para todos os grupos etários; para motricidade fina, motricidade global e esquema corporal as crian as de 3, 4 e 5 anos melhoraram seu desempenho entre as avalia es; para organiza o espacial somente as crian a
Construction validity in equilibrium tests: chronological order in tasks presentation
Carolina Silveira,Marcos Trindade Pinheiro Menuchi,Carolina Sant’Ana Sim?es,Maria Duarte Caetano
Revista Brasileira de Cineantropometria e Desempenho Humano , 2006,
Abstract: The equilibrium tests of the Rosa Neto1 Motor evelopment Scale are constituted by ten tasks related to the chronological ages from 2 to 11 years and they determine the participants Motor Age. The tests presentation order is crescent from the child chronological age and the motor age is based on the success or failure in each task. The aim of this study was to analyze the construction validity of the equilibrium motor tests observing the ordering the levels of task difficulty. 76 children with 6 to 9 years of chronological age participated and were assigned in two groups: control group, tests presentation in increased order; and inverted group, tests presentation in decreased order. The results did not revealed statistical significant differences between groups, which indicatethat the presentation order of the tests did not interfere in the children performance, independently of the chronological age. Low success rates occurred in some specific tasks followed by success in advanced tasks. As the results revealed that the participants could perform the tasks after that in which the failure happened the motor age ascribed by the Motor Development Scale can underestimate the children motor development. The variation of the children performance in the tasks suggests that the motor development process is nonlinear. The equilibrium motor tasks purposed in the Motor Development Scale show construction validity. RESUMO Os testes de equilíbrio da Escala de Desenvolvimento Motor de Rosa Neto1 s o constituídos por dez tarefas correspondentes às idades cronológicas de 2 a 11 anos e determinam a Idade Motora dos participantes. A ordem de apresenta o dos testes é crescente, partindo da idade cronológica da crian a e a idade motora baseia-se no sucesso ou fracasso em cada tarefa. O objetivo deste estudo foi analisar a validade de constru o dos testes motores em equilíbrio, observando a ordena o e os graus de dificuldade da tarefa. Participaram 76 crian as, com idade cronológica de 6 a 9 anos, que foram distribuídas em dois grupos: grupo controle, aplica o dos testes em ordem crescente; grupo invertido, aplica o dos testes em ordem decrescente. Os resultados n o apresentaram diferen as estatisticamente significativas no desempenho entre os grupos, indicando que a ordem de apresenta o dos testes n o interferiu no desempenho das crian as, independente da idade cronológica. Baixas taxas de sucesso ocorreram em algumas tarefas específicas, seguidas por sucesso em tarefas posteriores. Como os resultados demonstraram que os participantes conseguem executar tarefas segui
Construction validity in equilibrium tests: chronological order in tasks presentation
Carolina Silveira,Marcos Trindade Pinheiro Menuchi,Carolina Sant’Ana Sim?es,Duarte Caetano
Revista Brasileira de Cineantropometria e Desempenho Humano , 2006,
Abstract: The equilibrium tests of the Rosa Neto1 Motor evelopment Scale are constituted by ten tasks related to the chronological ages from 2 to 11 years and they determine the participants Motor Age. The tests presentation order is crescent from the child chronological age and the motor age is based on the success or failure in each task. The aim of this study was to analyze the construction validity of the equilibrium motor tests observing the ordering the levels of task difficulty. 76 children with 6 to 9 years of chronological age participated and were assigned in two groups: control group, tests presentation in increased order; and inverted group, tests presentation in decreased order. The results did not revealed statistical significant differences between groups, which indicatethat the presentation order of the tests did not interfere in the children performance, independently of the chronological age. Low success rates occurred in some specific tasks followed by success in advanced tasks. As the results revealed that the participants could perform the tasks after that in which the failure happened the motor age ascribed by the Motor Development Scale can underestimate the children motor development. The variation of the children performance in the tasks suggests that the motor development process is nonlinear. The equilibrium motor tasks purposed in the Motor Development Scale show construction validity. RESUMO Os testes de equilíbrio da Escala de Desenvolvimento Motor de Rosa Neto1 s o constituídos por dez tarefas correspondentes às idades cronológicas de 2 a 11 anos e determinam a Idade Motora dos participantes. A ordem de apresenta o dos testes é crescente, partindo da idade cronológica da crian a e a idade motora baseia-se no sucesso ou fracasso em cada tarefa. O objetivo deste estudo foi analisar a validade de constru o dos testes motores em equilíbrio, observando a ordena o e os graus de dificuldade da tarefa. Participaram 76 crian as, com idade cronológica de 6 a 9 anos, que foram distribuídas em dois grupos: grupo controle, aplica o dos testes em ordem crescente; grupo invertido, aplica o dos testes em ordem decrescente. Os resultados n o apresentaram diferen as estatisticamente significativas no desempenho entre os grupos, indicando que a ordem de apresenta o dos testes n o interferiu no desempenho das crian as, independente da idade cronológica. Baixas taxas de sucesso ocorreram em algumas tarefas específicas, seguidas por sucesso em tarefas posteriores. Como os resultados demonstraram que os participantes conseguem executar tarefas segui
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