Consulta: subjectFacets:"Radioisotopes"
Registros recuperados: 5
Data/hora: 09/06/2024 07:32:43

Análisis de la problemática de la contaminación por Cs-137 en los ecosistemas Antárticos
Provedor de dados: 20
Autores: Vega, M.; Rueda, M.; Valencia T., M.
La sensibilidad del medio ecológico Antártico obliga a conocer los diferentes niveles de contaminación de origen convencional y nuclear, con el fin de establecer posibles acciones tendientes a impedir que futuros accidentes e incidentes atenten contra sus ecosistemas. La evaluación de la concentración de Cs-137, como radionucleído gamma radiante, en agua, suelos y plantas, permite establecer la movilidad de este isótopo, considerando entre los más importantes elementos de contaminación originadas en los procesos de fisión nuclear. Se tomaron muestras de los tres medios anotados anteriormente, se las analizaron luego mediante espectroscopía gamma, encontrándose que en agua y en vegetales, los niveles de Cs-137 están por debajo de los límites de detección,...
Tipo: Journal Contribution
Palavras-chave: Radioisotopes; Radioactive contamination; Gamma radiation; Gamma spectroscopy; Biodiversity; Polar zones; Radioisotopes; Radioactive contamination; Gamma radiation; Biodiversity; Http://aims.fao.org/aos/agrovoc/c_6430; Http://aims.fao.org/aos/agrovoc/c_28321; Http://aims.fao.org/aos/agrovoc/c_3186; Http://aims.fao.org/aos/agrovoc/c_33949.
Ano: 1990
URL: http://hdl.handle.net/1834/3726

Concentración de Cesio-137 en dos perfiles de suelo en el área de Bahías Almirantazgo y Chile
Provedor de dados: 20
Autores: Schuller, P.; Lovengreen, Ch.; Vega, M.
Durante la Segunda Expedición Ecuatoriana a la Antártida, enmarcada en el proyecto de evaluación de radionucleídos en las Islas Shetland del Sur, se tomaron dos perfiles de suelo correspondientes a Bahía Almirantazgo, Isla Rey Jorge, y a Punta Fort Williams, Bahía Chile, Isla Greenwich. Las muestras fueron procesadas en la Universidad Austral de Chile. Los trabajos realizados en dichos perfiles son: Determinación de la concentración de Cs-137 y algunas características edáficas relevantes. Las muestras tomadas de un perfil practicado en Bahía Almirantazgo, se caracterizaron por una actividad superficial de Cs-137 considerablemente superior a la predicha para la banda latitudinal correspondiente. La penetración del Cs-137 es favorecida por la geomorfología y...
Tipo: Journal Contribution
Palavras-chave: Radioisotopes; Radioactive tracers; Radioactive contamination; Polar zones; Radioisotopes; Radioactive tracers; Radioactive contamination.
Ano: 1990
URL: http://hdl.handle.net/1834/3867

Absorption and mobility of radio-labelled calcium in chili pepper plants and sweet cherry trees
Provedor de dados: 63
Autores: Bonomelli,Claudia; Alcalde,Carolina; Aguilera,Camila; Videla,Ximena; Rojas-Silva,Ximena; Nario,Adriana; Fernandez,Victoria.
ABSTRACT: Calcium (Ca) is often supplied to crop species to prevent the occurrence of Ca–related disorders. Mechanisms of Ca absorption and transport are not fully understood and the effectiveness of root and/or foliar Ca fertilization may be variable. To characterize the rate of Ca absorption and transport, trials were developed with chili pepper and sweet cherry plants, using 45CaCl2 as a tracer. The Ca treatments supplied were: (1) No 45Ca (control); (2) 45Ca soil application; (3) 45Ca supply to basal leaves, and (4) 45Ca application to apical leaves. After two months, plants were harvested for biomass and Ca content determination. The recovery of 45Ca in different plant parts was measured with a liquid scintillation counter and leaf traits were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fertilizers; Fertilizer application methods; Horticultural crops; Plant nutrition; Radioisotopes.
Ano: 2021
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162021000601403

Study of gels of molybdenum with cerium in the preparation of generators of 99Mo - 99mTc
Provedor de dados: 52
Autores: Moraes,Vanessa; Marczewski,Bárbara; Dias,Carla Roberta; Osso Junior,João Alberto.
99mTc has ideal nuclear properties for organ imaging in nuclear medicine, and it is obtained from the 99Mo-99mTc generator. Four different types of generators are available: chromatographic that uses 99Mo from fission of uranium; MEK solvent extraction; Tc2O7 sublimation; gel chromatographic. This work presents the preparation of gel generators of molybdenum with cerium and characterization of the gels: mass ratio between molybdenum and cerium, structure, size of particles and elution percentage of 99mTc after irradiating the gels. Eight gels were prepared at the same temperature of 50 ºC with concentrations of NaOH of 2 and 4 mol/L, mass ratio of 0.31 and 0.38 and final pH of 3.5 and 4.5. The analysis of the results proved that these gels are not adequate...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Radioisotopes; Technetium-99m; Molybdenum-99; Gel generator.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000700007

Polymeric micelles and molecular modeling applied to the development of radiopharmaceuticals
Provedor de dados: 60
Autores: Grallert,Sibila Roberta Marques; Rangel-Yagui,Carlota de Oliveira; Pasqualoto,Kerly Fernanda Mesquita; Tavares,Leoberto Costa.
Micelles composed of amphiphilic copolymers linked to a radioactive element are used in nuclear medicine predominantly as a diagnostic application. A relevant advantage of polymeric micelles in aqueous solution is their resulting particle size, which can vary from 10 to 100 nm in diameter. In this review, polymeric micelles labeled with radioisotopes including technetium (99mTc) and indium (111In), and their clinical applications for several diagnostic techniques, such as single photon emission computed tomography (SPECT), gamma-scintigraphy, and nuclear magnetic resonance (NMR), were discussed. Also, micelle use primarily for the diagnosis of lymphatic ducts and sentinel lymph nodes received special attention. Notably, the employment of these diagnostic...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Radiopharmaceuticals/development; Polymeric micelles/diagnostic application; Radioisotopes; Imaging diagnostic agents; Diagnostic techniques.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502012000100002