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Search Results: 1 - 10 of 235644 matches for " Raúl Jorge Hernan;Mauro "
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Avalia??o da mutagenicidade e antimutagenicidade de um biopolímero extraído do microorganismo Agrobacterium radiobacter em camundongos Swiss
Primo, Milka Selestina;Calliari, Caroline Maria;Castro-Gómez, Raúl Jorge Hernan;Mauro, Mariana de Oliveira;Mantovani, Mário Sérgio;Oliveira, Rodrigo Juliano;
Revista Brasileira de Farmacognosia , 2010, DOI: 10.1590/S0102-695X2010000300009
Abstract: this study evaluated the mutagenic and ant mutagenic action of a biopolymer of glucose extracted from agrobacterium radiobacter (biopolymer of agrobacterium radiobacter). the experiment was conducted with swiss male mice divided into eight groups. treatment with the biopolymer was performed in a single dose by gavage at a dose of concomitant phosphate buffer groups in the evaluation of mutagenicity, or the agent of inducing dna damage, cyclophosphamide, the concentration of 50 mg/kg (body weight --b.w.), in groups of assessment ant mutagenic. we used the micronucleus test in peripheral blood. the blood sample was held 24 and 48 h after application of the test substances. statistical analysis showed that the biopolymer has no mutagenic activity and it is effective in preventing damage to dna. the percentages of damage reduction in groups of ant mutagenic were 83.9%, 89.1% and 103.1% in 24 h and 101.24%, 98.14% and 120.64% at doses of 48 to 75, 150 and 300 mg/kg (b.w.) respectively. the high percentage of damage reduction associated with the absence of mutagenic effects indicates the possibility of biopolymer chemoprotection action. it can also be considered a functional food candidate to be used as co-adjuvant chemotherapy to prevent side effects.
Production, characterization and technological properties of biopolymer produced by Agrobacterium radiobacter k84 Produ o, caracteriza o e propriedades tecnológicas de um biopolímero produzido por Agrobacterium radiobacter k84
Caroline Maria Calliari,Marciane Magnani,Raúl Jorge Hernan Castro Gómez
Semina : Ciências Agrárias , 2011,
Abstract: In this study, a biopolymer composed of carbohydrates (35%), protein (15%) and minerals (40%) was obtained through fermentation using sugar cane molasses as the sole carbon source for Agrobacterium radiobacter k84. The process yield was 10 gL-1 of biopolymer, which showed high solubility in water, neutral pH in aqueous solution and low water activity (0.52). The analysis in Scanning Electron Microscopy revealed microstructure characteristic of an amorphous solid, with particles of irregular shapes and sizes. In the evaluation of technological properties, the biopolymer showed formation of viscous solutions at room temperature from concentration of 0.5% in aqueous solution, gelling activity in solution at 2%, emulsifying (56.11±1.39%) and stabilizing activity (98.02±0.78%). The results suggest that the biopolymer from Agrobacterium radiobacter k84 is a promising candidate for industrial use. No presente estudo, utilizando mela o de cana-de-a úcar como única fonte de carbono para Agrobacterium radiobacter k84 foi obtido, em processo fermentativo, um biopolímero composto por carboidratos (35%), proteínas (15%) e minerais (40%). O rendimento do processo foi de 10 g.L-1 do biopolímero que apresentou elevada solubilidade em água, pH neutro em solu o aquosa e baixa atividade de água (0.52). As análises em Microscopia Eletr nica de Varredura revelaram microestrutura característica de um sólido amorfo, com partículas de formas irregulares e tamanhos variáveis. Na avalia o das propriedades tecnológicas, o biopolímero mostrou viscosidade à temperatura ambiente a partir da concentra o 0.5% em solu o aquosa, atividade geleificante em solu o a 2%, atividade emulsificante (56.11±0.78%) e estabilizante (98.02±1.39%). Os resultados sugerem o biopolímero de Agrobacterium radiobacter k84 como um candidato promissor para uso industrial.
Bacillus thuringiensis: general characteristics and fermentation Bacillus thuringiensis: características gerais e fermenta o
Elisangela Andrade Angelo,Gislayne Trindade Vilas-B?as,Raúl Jorge Hernan Castro-Gómez
Semina : Ciências Agrárias , 2010,
Abstract: The insect control is carried out mostly by chemical products, whose cumulative effects cause serious losses to environmental and human health, highlighting rapid selection of resistant insects. Biological control by entomopathogenic bacteria is an efficient alternative, mainly due to high specificity, absence of resistance in the target insects and low environment residual effect. Bacillus thuringiensis is a Gram-positive spore-forming bacterium that produces a parasporal crystal protein toxic for many insect species. Despite the widespread use of B. thuringiensis based products in biological control of insects, there are little studies about its multiplication, sporulation and crystal production, as so many trade secrets information. This revision was aimed at gathering general information about B. thuringiensis, as well as its production in culture media. O controle de insetos é realizado, em sua maioria, por produtos químicos; cujos efeitos cumulativos ocasionam grandes prejuízos ambientais e à saúde humana, destacando-se ainda a rápida sele o de insetos resistentes. O controle biológico por entomopatógenos é uma alternativa eficiente, principalmente devido a sua alta especificidade, ausência de resistência nos insetos alvos e baixo efeito residual no ambiente. Bacillus thuringiensis é uma bactéria Gram-positiva esporulante, produtora de cristais protéicos com atividade inseticida. Apesar do amplo uso B. thuringiensis no controle biológico, há poucos trabalhos publicados quanto a sua multiplica o, esporula o e produ o de cristais, visto que muitas informa es s o segredos industriais. Esta revis o teve por objetivo reunir informa es gerais sobre B. thuringiensis, bem como quanto sua produ o em meios de cultivo.
Antimicrobial activity of Lactobacillus and Bifidobacterium strains against pathogenic microorganisms “in vitro” Atividade antimicrobiana de Lactobacillus e Bifodobacterium frente a microrganismos patogênicos “in vitro”
Giselle Nobre Costa,Helio Hiroshi Suguimoto,Lucia Helena da Silva Miglioranza,Raúl Jorge Hernan Castro Gómez
Semina : Ciências Agrárias , 2012,
Abstract: Lactobacilli and bifidobacteria have a long history of safe use in foods. These bacteria have biotechnological characteristics of interest such as the inhibition of pathogens. In this work, two lactobacilli strain and a bifidobacterium strain isolated from human gut were evaluated concerning to their ability to inhibit pathogenic microorganisms in foods by diffusion agar tests. Moreover, we assessed the metabolites produced in culture broth under static and shaking growth to simulate anaerobiosis and aerobiosis conditions, respectively. L. acidophilus LA5, L. plantarum DCTA 8420 and B. lactis DCTA 8724 showed ability to inhibit S. aureus FRI 196, strains producer toxins A and D, as well as B. cereus ATCC 25923, E. coli ATCC 25922 and S. Enteritidis, whose inhibition halos reached, on average, 24 mm in diameter. In the agar diffusion method with concentrated culture medium, it was possible to observe the effect of oxygen on the production of toxic substances. This result showed that cultivation of Lactobacillus under aerobic conditions seems to exert greater inhibitory effect, whereas for Bifidobacterium strain the effect was the opposite. Lactobacilos e bifidobactérias apresentam um longo histórico de uso seguro em alimentos, além de apresentarem características de interesse biotecnológico como a inibi o de patógenos. Neste trabalho duas linhagens de lactobacilos e uma de bifidobactéria, isoladas do intestino humano, foram avaliadas em testes de difus o em ágar, quanto à capacidade de inibi o de microrganismos patogênicos de ocorrência comuns em toxinfec es alimentares. Adicionalmente, foram avaliados os metabólitos produzidos em caldo de cultivo estático e em agita o para simular condi es de anaerobiose a aerobiose, respectivamente. As três bactérias, L. acidophilus LA5, L. plantarum DCTA 8420 e B. lactis DCTA 8724 apresentaram capacidade de inibi o para S. aureus FRI 196 linhagem produtora de toxinas A e D, assim como para B. cereus ATCC 25923, E. coli ATCC 25922 e S. Enteritidis, cujos halos de inibi o apresentaram em média 24 mm de diametro. No método de difus o em ágar com meio de cultivo concentrado, foi possível observar o efeito do oxigênio sobre a produ o de substancias tóxicas aos microrganismos indicadores, evidenciando que Lactobacillus cultivados em aerobiose, parece produzir metabólitos com maior efeito inibitório, enquanto que, para a linhagem de Bifidobacterium, o efeito foi oposto.
Política y Filosofía en Lisandro de la Torre
De Miguel,Jorge Raúl;
Estudios de filosof?-a pr??ctica e historia de las ideas , 2006,
Abstract: the article analyses lisandro de la torre's philosophical ideas. he was an important argentinian politician, who had an active public life, mainly, as a legislator, between 1890 and 1937. the study is based upon some lectures and writings from his last years. his cosmological view is examined through the relation among philosophy, science and religion, on one hand, and through his anthropological account, on the other hand. the influence of pantheism and positivism is pointed out in both perspectives. it is criticised de la torre's claim about politics as an anti-philosophical activity by arguing that philosophy and politics may be considered as foundations of his thought.
Cableando el norte de México: la evolución de la industria maquiladora de arneses
Jorge Carrillo,Raúl Hinojosa
Región y sociedad , 2001,
Abstract: La industria de los cables de arneses automotrices en México se inició en los ochentas y actualmente es el principal producto de exportación maquilador, y el segundo después de los motores dentro de la industria. Desde sus orígenes como una industria de ensamble simple con algunas plantas, ha logrado convertirse en el principal conglomerado industrial en estados como el de Chihuahua. Productores, competidores, proveedores y empresas de servicios dan cuenta de un cambio sustantivo en este proceso de aglomeración. El volumen de empleo ha aumentado considerablemente, y empresas de auto partes como Delphi son actualmente la principal fuente de ocupación privada en México. Tan sólo en materia de arneses, cuenta con 40,000 empleados. La evolución de esta industria se refleja en el cambio de rol del producto y en el avance tecnológico. Se ha convertido en el sistema nervioso central del automóvil, y en la medida en que aumentan el contenido tecnológico de los vehículos y la producción de sistemas integrados y modulares, su papel es cada vez más relevante. El artículo concluye, sin embargo, con la observación de que en el largo plazo las empresas de ensamble de arneses pueden emigrar hacia otras regiones más baratas como China.
Contenido de flavonoides y compuestos fenólicos de mieles chilenas e índice antioxidante
Mu?oz, Orlando;Copaja, Silvia;Speisky, Hernan;Pe?a, Raúl C.;Montenegro, Gloria;
Química Nova , 2007, DOI: 10.1590/S0100-40422007000400017
Abstract: a comparison of the phenolic content of several chilean honeys showed great variations in flavonoid concentration among the samples analysed. higher amounts of phenolics are found in honey from dry climates. the antioxidant effect of extracts, using orac analysis, did not correlate with the flavonoid content or with the total phenolic concentration.
Rainfall Rate Duration Study for Performance Assessment of Satellite Communication Links
Jorge L. Cerqueira,Mauro S. Assis
International Journal of Microwave Science and Technology , 2013, DOI: 10.1155/2013/209067
Abstract: The duration of rainfall events as a function of precipitation rate is investigated in this paper. The experimental data used in this study were measured along a rain gauge network with 8 pluviographs located in the Amazon region. The most important point to be highlighted in this study is the evidence of a correlation between rain and fade events durations observed in a 12?GHz satellite link. This result is quite important under the engineering point of view, once it can be used in the design of improvement techniques for low availability satellite systems. 1. Introduction In the planning of low availability satellite systems, an outage of 1% to 0.1% in the worst month is normally acceptable. In these systems the temporal variability of fading has a strong impact on system design. Consequently, the knowledge of rain dynamics is of fundamental relevance. It is recognized that the conversion of rain rate duration to slant path duration statistics is not an easy task [1]. The main problems are the vertical nonhomogeneity of rain structure and the possibility of having more than one rain cell along the propagation path. However, according to Timothy et al. [2], if the vertical distribution of rain is uniform from the earth surface to a height near the 0° isotherm level and the elevation angle is higher than 30°, the measured rainfall rate threshold at a given probability level may be used to obtain information on the dynamics associated with the attenuation in slant path. A study by Lekkla and Prapinmongkolkarn [3] corroborates this assertion. In this context, based on measurements carried out in the Brazilian Amazon region, this paper investigates the duration of rainfall events as a function of precipitation rate. Figure 1 shows the rain gauge network used in the study described here and details about these sites are presented in Table 1. Table 1: Description of the experimental sites. Figure 1: Rain gauge network. 2. Rainfall Rate Events Duration Statistics In each site shown in Figure 1, measurements of rain duration were carried out for a total period of one year between 2003 and 2005. The integration time of precipitation rate was 10s to be near the instantaneous value and more adequate to be aligned with the dynamics of signal attenuation. An example of rain duration statistics for the 8 sites illustrated in Figure 1 and a rain rate threshold of 50?mm/h is depicted in Figure 2. It is noted that, with only one exception, all the other sites have shown the same behaviour. The exception was in the site of Cruzeiro do Sul [7°36′S; 72°40′W] where a large
Telemedicina: aprovechando las tecnologías para favorecer el impacto social Telemedicina: aprovechando las tecnologías para favorecer el impacto social
Guillermo Rodolfo Friedrich,Jorge Raúl Ardenghi
Revista Eletr?nica de Sistemas de Informa??o , 2006,
Abstract: En general la palabra telemedicina se asocia con cuestiones muy complejas y sofisticadas, como por ejemplo la realización de una cirugía a distancia, en la que están involucrados sistemas de comunicación, visualización y robótica basados en tecnologías de punta y de costos muy elevados. Si bien este tipo de aplicaciones es una de las más notorias dentro del campo de la telemedicina, tiene por ahora un costo muy elevado y un impacto social muy bajo. Si se plantea como un objetivo de la telemedicina acercar lacatención médica a poblaciones alejadas de los centros urbanos, y que por lo general cuentan con recursos económicos limitados, el punto de vista es otro. En lugar de buscar el desarrollo de nuevas tecnologías de punta se debe tratar de aprovechar y potenciar las tecnologías existentes. Como la base de cualquier sistema de telemedicina es la infraestructura de comunicaciones, en el presente trabajo se analizan las posibilidades de algunas tecnologías de comunicación e incluso la complementación entre ellas. En general la palabra telemedicina se asocia con cuestiones muy complejas y sofisticadas, como por ejemplo la realización de una cirugía a distancia, en la que están involucrados sistemas de comunicación, visualización y robótica basados en tecnologías de punta y de costos muy elevados. Si bien este tipo de aplicaciones es una de las más notorias dentro del campo de la telemedicina, tiene por ahora un costo muy elevado y un impacto social muy bajo. Si se plantea como un objetivo de la telemedicina acercar la atención médica a poblaciones alejadas de los centros urbanos, y que por lo general cuentan con recursos económicos limitados, el punto de vista es otro. En lugar de buscar el desarrollo de nuevas tecnologías de punta se debe tratar de aprovechar y potenciar las tecnologías existentes. Como la base de cualquier sistema de telemedicina es la infraestructura de comunicaciones, en el presente trabajo se analizan las posibilidades de algunas tecnologías de comunicación e incluso la complementación entre ellas.
Diagnóstico de instalaciones de transporte de hidromezcla afectadas por cavitación
Jorge L. Reyes-Cruz,Raúl Izquierdo-Pupo
Minería y Geología , 2007,
Abstract: Se fundamenta de forma experimental la relación entre niveles de vibración y altura de succión en bombas centrífugas de instalaciones de transporte de hidromezclas en la industria del níquel. Se establecen las etapas del régimen cavitacional y se plantea el procedimiento para el diagnóstico de instalaciones afectadas por la cavitación. La presencia de cavitación se define a partir del conocimiento de los factores hidráulicos que influyen sobre la carga neta de succión de la instalación. Se ofrecen las ecuaciones que rigen la presencia de este fenómeno y se establecen los niveles de vibraciones en los que la instalación debe operar para garantizar los parámetros técnicos y económicos.
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