997 resultados para Representaciones moleculares


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Tras el fallecimiento del presidente venezolano Hugo Chávez, en el año 2013, el gobierno venezolano ha utilizado la figura líder revolucionario como eje de articulación para realizar trabajos de encuadramiento de la memoria en distintos espacios públicos del país. Lo anterior se ha traducido en la resignificación de lugares, acontecimientos, personajes y planteamientos políticos relacionados con la Revolución Bolivariana. El siguiente ensayo aborda al mausoleo presidencial "Cuartel de la Montaña 4-F" como objeto de estudio para analizar, a través de las representaciones simbólicas realizadas por los sectores civiles y militares que conviven dentro del chavismo, cómo son las relaciones de articulación y disputas de estos actores sociales en torno a la memoria de Chávez que cada uno construye actualmente

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En la actualidad, la localidad de Dock Sud es uno de los lugares más contaminados del país y, cuando esta cuestión ambiental es tratada en los medios de comunicación, se instala en la agenda pública. El propósito de este trabajo consistió en explorar, desde una perspectiva integral del paisaje, las representaciones sociales que tiene la población de Dock Sud de su problemática ambiental teniendo en cuenta los valores simbólicos, la representación paisajística y el referente ambiental. Para ello, se plantearon dos objetivos específicos de investigación. En primer lugar, identificar la noción de paisaje en las representaciones sociales que tiene la población de Dock Sud; y, en segundo, explorar las estrategias de resistencia y adaptación llevadas a cabo por la población ante el avance de la actividad industrial-petroquímica en el área. Se utilizaron técnicas cualitativas, específicamente, entrevistas en profundidad, que se realizaron a pobladores representativos de distintos grupos delimitados según su tiempo de residencia en el lugar y la participación en actividades políticas. También se analizaron artículos periodísticos sobre la cuestión ambiental publicados en un diario local y en uno de alcance nacional, con el fin de relevar comparativamente cómo se construye el tema en los distintos medios

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En este trabajo se propone investigar sobre las representaciones que tienen los habitantes de la localidad de Dock Sud ante la grave situación ambiental del área e indagar si han tenido la capacidad para formular estrategias y acciones comunes, en procura de una solución al problema ambiental. Para ello se analizarán los factores y características económicas y territoriales que propiciaron tal situación de riesgo ambiental, para poder así identificar y describir a los actores implicados y a sus estrategias de lucha. El interés en esta cuestión nace del hecho de que la zona que se quiere investigar es de alto riesgo ambiental por la instalación cercana del puerto y del polo petroquímico que contiene dársenas de inflamables y propano. Además por estar instalado en medio de una alta densidad poblacional y ocasionando gravísimos daños ambientales con impacto adverso en la salud de la gente, se han levantado voces solicitando la relocalización del mismo o de la población. Por ello y ante esta situación con este trabajo se tratará de explorar la actitud de los habitantes ante el peligro, identificar la existencia de formas organizativas cuyo propósito sea accionar para solucionar el problema ambiental e indagar acerca de cómo se fueron gestando esas organizaciones, cómo son las formas de participación, qué acciones se realizaron y con que resultados, y cuál es la situación organizativa actual

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Thesis (Master's)--University of Washington, 2016-06

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The use of fossil fuels has been considered one of reason for the increase of pollution in the atmosphere and it may be related to the climate changes. Then, the research of the new sources of fuels will be important. Considering this, the use of biodiesel has been considered not as bad as petrol. The castor bean (Ricinus communis L.) is an important oilseed, which belongs to Euphorbiaceae family, and the oil found in the seed has important characteristics for biodiesel. This plant is considered as “rustic” as it does not need so much water for its development and oil production. Due to this, this plant has been considered to be ideal in semi-arid regions, such as the Northeast of Brazil. The aim of his study is to better understand the responses to abiotic stresses (drought and salinity) from castor bean plants using morphological, physiological and molecular tools. In order to do this, the castor bean plants were subjected to salt stress (50, 100, 150 and 200 mM NaCl) in a controlled environment and drought stress (5, 10, 15 days and 10 days cyclic). After these treatments, these plants were subjected to different analyzes: a) the expansion and retention of water from leaves; b) anatomy using leaves and roots. Based on these results, we found that castor suffered decrease in leaf area with increase drought stress, however restricted water loss, probably by accumulation of compatible solutes in the leaves. The anatomy data showed modifications in the vascular system. These modifications observed suggested that castor bean plant may be resistant to stress as it was verified in 5 days of drought as well as in 100 mM NaCl. In both conditions, these plants were fine. Probably these plants keep some solutes in the cell and then maintain the cell tugor. The data obtained in this study gave a better idea how castor bean plant responds to abiotic stress conditions - drought and salt stress

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Brazil is among the largest cashew nut producers of the world. However, the roasting process is still carried out artisanally, especially in the Brazilian semiarid region. In face of this occupational problem, the aim of this study was to perform a physical-chemical characterization of the particulate matter (PM) emitted by the roasting of cashew nuts, as well as to determine the occupational risk and molecular mechanisms associated. The most evident PM characteristics were the prevalence of fine particles, typical biomass burning morphologies such as tar ball and the presence of the elements K, Cl, S, Ca and Fe. In addition, atmospheric modeling analyses suggest that these particles can reach neighboring regions of the emission source. Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic potential, such as benzo[a]pyrene, dibenz[a,h]anthracene, benzo[a]anthracene, benzo[b]fluoranthene, chrysene, benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene and benzo[j]fluoranthene were the most abundant PAHs found in the two air monitoring campaigns. Among the identified oxy-PAH the benzanthrone (7H-benz[d,e]anthracen-7-one) had the highest concentration and the evaluation of lifetime cancer risk showed an increase of 12 to 37 cases of cancer for every 10,000 exposed people. Chemical analysis of roasted cashew nuts identified the PAHs: phenanthrene, benzo[g,h,i]perylene, pyrene and benzo[a]pyrene, besides the 3-pentadecilfenol allergen (urushiol analogue) as prevalent. Occupational exposure to PAHs was confirmed by the increase of urinary 1-hydroxypyrene levels and genotoxic effects were evidenced by the increase on micronuclei and nuclear bud frequency in exfoliated buccal mucosa cells among the exposed workers. Other biomarkers of effects such as karyorrhexis, pyknotic, karyolytic, condensed chromatin and binucleated cells also have their frequencies increased when compared to an unexposed control group. The investigation of the molecular mechanisms associated with the PM organic extract showed cytotoxicity in human lung cell lines (A549) at concentrations ≥ 4 nM BaPeq. Using non-cytotoxic doses the extract was able to activate proteins involved in the DNA damage response pathway (Chk1 and p53). Moreover, the specific contribution of the four most representative PAHs in the cashew nut roasting sample showed that benzo[a]pyrene was the most efficient to activate Chk1 and p53. Finally, the organic extract was able to increase persistently the mRNA expression involved in the PAHs metabolism (CYP1A1 and CYP1B1), inflammatory response (IL-8 and TNF-α) and cell cycle arrest (CDKN1A) for DNA repair (DDB2). The high PM concentrations and its biological effects associated warn of the serious harmful effects of artisanal cashew nut roasting and urgent actions should be taken to the sustainable development of this activity.

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Brazil is among the largest cashew nut producers of the world. However, the roasting process is still carried out artisanally, especially in the Brazilian semiarid region. In face of this occupational problem, the aim of this study was to perform a physical-chemical characterization of the particulate matter (PM) emitted by the roasting of cashew nuts, as well as to determine the occupational risk and molecular mechanisms associated. The most evident PM characteristics were the prevalence of fine particles, typical biomass burning morphologies such as tar ball and the presence of the elements K, Cl, S, Ca and Fe. In addition, atmospheric modeling analyses suggest that these particles can reach neighboring regions of the emission source. Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic potential, such as benzo[a]pyrene, dibenz[a,h]anthracene, benzo[a]anthracene, benzo[b]fluoranthene, chrysene, benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene and benzo[j]fluoranthene were the most abundant PAHs found in the two air monitoring campaigns. Among the identified oxy-PAH the benzanthrone (7H-benz[d,e]anthracen-7-one) had the highest concentration and the evaluation of lifetime cancer risk showed an increase of 12 to 37 cases of cancer for every 10,000 exposed people. Chemical analysis of roasted cashew nuts identified the PAHs: phenanthrene, benzo[g,h,i]perylene, pyrene and benzo[a]pyrene, besides the 3-pentadecilfenol allergen (urushiol analogue) as prevalent. Occupational exposure to PAHs was confirmed by the increase of urinary 1-hydroxypyrene levels and genotoxic effects were evidenced by the increase on micronuclei and nuclear bud frequency in exfoliated buccal mucosa cells among the exposed workers. Other biomarkers of effects such as karyorrhexis, pyknotic, karyolytic, condensed chromatin and binucleated cells also have their frequencies increased when compared to an unexposed control group. The investigation of the molecular mechanisms associated with the PM organic extract showed cytotoxicity in human lung cell lines (A549) at concentrations ≥ 4 nM BaPeq. Using non-cytotoxic doses the extract was able to activate proteins involved in the DNA damage response pathway (Chk1 and p53). Moreover, the specific contribution of the four most representative PAHs in the cashew nut roasting sample showed that benzo[a]pyrene was the most efficient to activate Chk1 and p53. Finally, the organic extract was able to increase persistently the mRNA expression involved in the PAHs metabolism (CYP1A1 and CYP1B1), inflammatory response (IL-8 and TNF-α) and cell cycle arrest (CDKN1A) for DNA repair (DDB2). The high PM concentrations and its biological effects associated warn of the serious harmful effects of artisanal cashew nut roasting and urgent actions should be taken to the sustainable development of this activity.

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La esofagitis eosinofílica (EEo) es una enfermedad esofágica alérgica de creciente incidencia. Afecta a niños y adultos jóvenes, principalmente hombres (razón 3:1), encontrándose enfermedades atópicas subyacentes (asma y/o rinoconjuntivitis estacional, dermatitis atópica, alergia alimentaria) en el 80%-90% de los casos. Los primeros criterios diagnósticos para la EEo, publicados en el año 2007, se basaban en la conjunción de tres criterios mayores: datos clínicos (síntomas de disfunción esofágica), datos histológicos (infiltración epitelial esofágica por eosinófilos > 15 eos/cga) y ausencia de respuesta a inhibidores de la bomba de protones (IBP) o pHmetría esofágica normal. Sin embargo, la gran mayoría de los pacientes con síntomas de disfunción esofágica e inflamación esofágica eosinofílica eran diagnosticados de EEo sin confirmación de la respuesta a IBP o realización de pHmetría. Por tanto, existía un riesgo evidente de infraestimación de la respuesta a IBP en estos pacientes. Este incumplimiento de las premisas diagnósticas de consenso no sólo impedía cuantificar el porcentaje de pacientes que eran respondedores a IBP, sino que hacía que pacientes potencialmente respondedores a IBP recibieran otros tratamientos específicos para la EEo (corticoides tópicos, dietas de eliminación), los cuales, comparados con los IBP, provocan mayor cantidad de efectos adversos o podían limitar notablemente la calidad de vida de los pacientes. Inmediatamente después de la publicación de las primeras recomendaciones diagnósticas en el año 2007, se comunicaron pequeñas series retrospectivas de pacientes pediátricos con eosinofilia esofágica sintomática que alcanzaron remisión completa con IBP, tanto con pHmetría normal como patológica. Por tanto, estas series iniciales comenzaron cuestionar el papel diagnóstico de la pHmetría y su capacidad para predecir la respuesta a IBP...

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Fil: Manuele, Matías Eugenio. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.