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Search Results: 1 - 10 of 4685 matches for " Olaya Lorenzo "
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Characterization of Doped Amorphous Silicon Thin Films through the Investigation of Dopant Elements by Glow Discharge Spectrometry: A Correlation of Conductivity and Bandgap Energy Measurements
Pascal Sánchez,Olaya Lorenzo,Armando Menéndez,Jose Luis Menéndez,David Gomez,Rosario Pereiro,Beatriz Fernández
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12042200
Abstract: The determination of optical parameters, such as absorption and extinction coefficients, refractive index and the bandgap energy, is crucial to understand the behavior and final efficiency of thin film solar cells based on hydrogenated amorphous silicon (a-Si:H). The influence of small variations of the gas flow rates used for the preparation of the p-a-SiC:H layer on the bandgap energy, as well as on the dopant elements concentration, thickness and conductivity of the p-layer, is investigated in this work using several complementary techniques. UV-NIR spectrophotometry and ellipsometry were used for the determination of bandgap energies of four p-a-SiC:H thin films, prepared by using different B 2H 6 and SiH 4 fluxes (B 2H 6 from 12 sccm to 20 sccm and SiH 4 from 6 sccm to 10 sccm). Moreover, radiofrequency glow discharge optical emission spectrometry technique was used for depth profiling characterization of p-a-SiC:H thin films and valuable information about dopant elements concentration and distribution throughout the coating was found. Finally, a direct relationship between the conductivity of p-a-SiC:H thin films and the dopant elements concentration, particularly boron and carbon, was observed for the four selected samples.
La promesa de igualdad, en la democracia, sigue siendo un debate para las mujeres
Olaya, Eucaris;
Revista Katálysis , 2010, DOI: 10.1590/S1414-49802010000100007
Abstract: this article offers a critical reflection on the inequalities that women confront in situations considered democratic and plural. nevertheless, it is necessary to question the "promise of political equality for women" in contexts controlled by the market economy, war and corruption, which are factors that impede the construction of democracy and citizenship. throughout history, women have conducted a permanent debate with what is considered democracy, equality, citizenship and development. the social movement of women and feminists in colombia presents various proposals for the construction of a true democracy that guarantees equality and complete rights of citizenship, in contrast to the logic of violence and war that confronts the country.
Liisa Flora Voionmaa Tanner, Escultura Pública. Del Monumento Conmemorativo a la Escultura Urbana. Santiago 1792-2004
Olaya Sanfuentes
Historia (Santiago) , 2006,
Abstract:
PABLO LACOSTE, La Mujer y el Vino. Entre el Reino de Chile y el Virreinato del Río de la Plata, 1561-1810
Olaya Sanfuentes
Historia (Santiago) , 2009,
Abstract:
ALONSO DE GóNGORA Y MARMOLEJO, Historia de todas las cosas que han acaecido en el reino de Chile y de los que lo han gobernado
OLAYA SANFUENTES
Historia (Santiago) , 2012,
Abstract:
ISABEL CRUZ AMENáBAR, Lily Garafulic. Forma y signo en la escultura chilena contemporánea
OLAYA SANFUENTES
Historia (Santiago) , 2004,
Abstract:
Aplicación del método de mínimos cuadrados al ajuste de curvas granulométricas de áridos
Olaya, Manuel
Materiales de Construccion , 1978,
Abstract: A partir de la lectura del artículo original rese ado en la llamada (1), en el Departamento de Materiales de Construcción del I.E.T.c.c, se han comprobado algunos ajustes granuiométricos de áridos obtenidos por otros métodos clásicos con los resultados que se obtienen aplicando el presente método. La buena correspondencia entre unos y otros ha sido el motivo que ha impulsado a darlo mayor difusión.
Consideraciones sobre granulometrías discontinuas de máxima compactación
Olaya, Manuel
Materiales de Construccion , 1978,
Abstract: Los materiales conglomerados que se presentan en la naturaleza deben su génesis estructural a la acomodación geométrica de unos y otros componentes. Tras un proceso de "cimentación", este acomodo, según sea la disposición particular, conlleva por parte del material una respuesta resistente frente a las acciones exteriores impuestas. Sobre esta idea cabe suponer que los conglomerados más resistentes serán aquellos que tengan su estructura fundamentada en los interapoyos de los granos más duros y resistentes. ya que de por sí el material cementante proviene en la mayoría de los casos de otros previamente meteorizados a los que la evolución geológica ha colocado entre los primeros.
Oxidative stress and inflammation in liver carcinogenesis
Natalia Olaya
Iatreia , 2007,
Abstract: Inflammation is a common response in the human liver. It is involved in chronic hepatitis, cirrhosis, steatosis, ischemiareperfusion damage, hepatocarcinomas and in the development of metastasis. Reactive oxygen species (ROS) production is part of the inflammatory processes. It is implicated in many physiological and pathological situations and can induce mutations in key cancer genes. Normally, this process is prevented by DNA repair enzymatic systems that maintain sequence fidelity during DNA replication. However, overproduction of free radicals in chronic inflammatory diseases is thought to saturate the ability of the cell to repair DNA damage prior to replications. Inflammation-induced genetic damage is not unique to the liver, and it might contribute to the development of mutations in several organs. An example is the chronic inflammatory response in ulcerative colitis that ultimately could lead to neoplasia. There is compelling evidence to suggest that most known environmental risk factors for HCC development lead to generation of reactive oxygen species (ROS). Indeed, hepatitis C virus (HCV), alcohol and hepatitis B virus (HBV) have all been associated with oxidative stress. Direct production of oxidative stress by HCV core protein has been shown. A link between oxidative stress and liver pathogenesis is also supported by the successful use of antioxidant therapy to treat liver injury caused by chronic HCV infection, although it is not currently used for effective therapy. Ethanol metabolism via the alcohol dehydrogenase pathway and microsomal ethanol oxidizing system contribute substantially to the production of acetaldehyde and generation of ROS. HBx via its association with mitochondria has been shown to induce oxidative stress which in turn leads to activation of a series of transcription factors. Moreover, in addition to direct production of ROS by these pathogens, liver infiltration by activated phagocytic cells provides an additional source of ROS production that promotes oxidative stress via interleukin or NO production that can damage proteins, lipids and DNA. Nuclear MSI was demonstrated first in familial hereditary colorectal cancer (HNPCC) and then in sporadic cancers, primarily digestive tract cancers such as colorectal, gastric and pancreatic cancers.In HCC, although nuclear MSI has been shown in some studies (15,18), there is as yet no direct evidence of alteration of the MMR genes and the biological and the clinicopathological significance of the lowlevel MSI seen in HCC is unclear. MSI has also been shown to occur in inflammatory
Una visión más allá de la enfermedad
Olaya Patricia
Avances en Enfermería , 1991,
Abstract: A medida que acontecen situaciones de evolución mundial, se hacen replanteamientos en las formulaciones, acciones y definiciones para abordar los problemas sociales. En particular, los de salud-enfermedad, se han caracterizado por ser resueltos de una manera unilateral, contestataria, desacorde con las causas socio-económicas y hasta descontextualizadas de las prácticas, creencias y valores de quienes en el tercer mundo padecemos los problemas.
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