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In recent years, Brazilian Nuclear Programme has been reviewed and updated by government authorities in face of the demand for energy supply and its associated environmental constraints. The immediate impact of new national programmes and projects in nuclear field is the increase in the number of exposed personnel and the consequent need for reliable dosimetry services in the country. Several Technical Documents related to internal dosimetry have been released by the International Atomic Energy Agency and International Commission on Radiological Protection. However, standard bioassay procedures and methodologies for bioassay data interpretation are still under discussion and, in some cases, both in routine and emergency internal monitoring, procedures can vary from one laboratory to another and responses may differ markedly among Dosimetry Laboratories. Thus, it may be difficult to interpret and use bioassay data generated from different laboratories of a network. The main goal of this work is to implement a National Network of Laboratories aimed to provide reliable internal monitoring services in Brazil. The establishment of harmonised in vivo and in vitro radioanalytical techniques, dose assessment methods and the implementation of the ISO/IEC 17025 requirements will result in the recognition of technical competence of the network.

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Internal exposures may occur in nuclear power plants, radioisotope production, and in medicine and research laboratories. Such practices require quick response in case of accidents of a wide range of magnitudes. This work presents the design and calibration of a mobile laboratory for the assessment of accidents involving workers and the population as well as for routine monitoring. The system was set up in a truck with internal dimensions of 3.30 m × 1.60 m × 1.70 m and can identify photon emitters in the energy range of 100-3,000 keV in the whole body, organs, and in urine. A thyroid monitor consisting of a lead-collimated NaI(Tl)3" × 3" (7.62 × 7.62 cm) detector was calibrated with a neck-thyroid phantom developed at the IRD (Instituto de Radioproteção e Dosimetria). Whole body measurements were performed with a NaI(Tl)8" × 4" (20.32 × 10.16 cm) detector calibrated with a plastic-bottle phantom. Urine samples were measured with another NaI(Tl) 3" × 3" (7.62 × 7.62 cm) detector set up in a steel support. Standard solutions were provided by the National Laboratory for Metrology of Ionizing Radiation of the IRD. Urine measurements are based on a calibration of efficiency vs. energy for standard volumes. Detection limits were converted to minimum committed effective doses for the radionuclides of interest using standard biokinetic and dosimetric models in order to evaluate the applicability and limitations of the system. Sensitivities for high-energy activation and fission products show that the system is suitable for use in emergency and routine monitoring of individuals under risk of internal exposure by such radionuclides.

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In Brazil, the radionuclides used for therapy are: (131)I, (153)Sm, (90)Y and (177)Lu, both for routine or research protocols. The radionuclide activity excreted by patients may be quantified by bioassay analysis and constitutes a powerful tool for individual treatment planning. The Bioassay Laboratory (LBIOVT) of the Institute of Radiation Protection and Dosimetry (IRD) has equipments for gamma and beta spectroscopy. These systems are calibrated in energy and efficiency using reference sources supplied by the National Laboratory of Radiation Metrology (LMNRI/IRD). The LBIOVT has operational procedures according ISO-ABNT-17025 recommendations and participates of international and national intercomparisons. The patient samples are collected immediately after radiopharmaceutical administrations, at the hospital or at the patient residence, and are handled, stored and transported according national radiation protection regulations. The radionuclide specific activity (Bq/L) is referenced to date and time of excretion, for the estimation of the individual biological half-live. The volume of excreta may carefully manipulated in order to avoid losses and misinterpretation in the activity quantification. The process of the LBIOVT accreditation and its participation in intercomparisons may guarantee the confidence of the results, allowing the minimization of the uncertainties in the individual monitoring.

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Under the auspices of the Regional Coordination Agreement for Latin America, representatives of the eight member states have participated in a project to improve radiological protection for workers exposed to unsealed sources of radiation. The design of the project was based on information obtained from a questionnaire circulated among the participants, from which the initial status of internal dosimetry services in each country was characterised. The objective of the project is to harmonize internal dosimetry procedures, with reference to International Atomic Energy Agency recommendations. After the implementation of new procedures and personnel training, four intercomparison exercises were carried out: measurement of iodine in thyroid phantoms, measurement of gamma emitters in urine samples, measurement of beta emitters in urine samples and internal dose assessments. This project has resulted in important improvements in internal dosimetry services in the region.

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A composição do óleo essencial de Lippia alba apresenta variação quantitativa e qualitativa, levando à separação em quimiotipos. O trabalho tem como objetivo analisar o óleo essencial de folhas de três quimiotipos de Lippia alba, provenientes de diferentes regiões do Brasil, cultivados em condições semelhantes, a fim de verificar se as diferenças na composição do óleo devem-se a fatores ambientais ou a variação genética infraespecífica e se a floração influencia o rendimento e a composição do óleo. Os quimiotipos produtores de citral, carvona e linalol, foram denominados Lippia alba 1, 2 e 3, respectivamente. Os óleos essenciais foram extraídos por hidrodestilação de folhas e analisados por cromatografia com fase gasosa e cromatografia com fase gasosa acoplada ao espectrômetro de massas. O melhor rendimento foi obtido das plantas no estágio vegetativo. A composição do óleo essencial manteve-se inalterada para os três quimiotipos após cultivo em condições semelhantes e também não variou qualitativamente durante o crescimento vegetativo e floração. Os dados obtidos reforçam a idéia que as diferenças na composição do óleo essencial dos quimiotipos refletem variações genotípicas entre as plantas e que a extração de óleo essencial de L. alba deve ser efetuada na fase de crescimento vegetativo, quando é maior o rendimento do óleo e a porcentagem dos componentes majoritários.

The composition of Lippia alba essential oil varies in a manner that different chemotypes are recognized. This work deals with the analysis of the essential oil from three chemotypes of L. alba from different regions of Brazil, cultivated in similar conditions, to verify if the differences in their chemical composition can be due to environmental conditions or may be due to infra-specific genetic variation. The influence of flowering was investigated regarding essential oil yield and composition. The chemotypes producing citral, carvone and linalol were denominated chemotypes 1, 2 and 3, respectively. The essential oils were obtained by hydrodistillation of the leaves, at flowering and vegetative growth stages. Essential oils were analyzed by GC and GC/MS. A better yield was obtained from plants at vegetative stage. The composition of the essential oils remained unchanged after cultivation in the same conditions, and did not vary qualitatively during flowering and vegetative periods. Relative percentages of the major compounds changed during flowering period. Data obtained allow us to reinforce the idea that differences in the essential oil composition of the three chemotypes are due to genotypic variations and that the essential oil extraction during the vegetative period enables a better yield and higher percentages of the major compounds.

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The high concentration of uranium and thorium in certain Brazilian areas provides an opportunity to evaluate the radiation exposure due to intake of radionuclides by the populations that live and work in areas with a high natural radiation background. Buena, where this study was conducted, is a small village on the coast in the northern part of Rio de Janeiro State, characterised by the presence of a large deposit of monazite sand. In this paper, the concentrations of 238U, 234U, 232Th, 228Th, 228Ra, 226Ra and 210Pb in faecal samples from inhabitants of this area were determined by a sequential analytical method. The results of the average concentrations in faeces of inhabitants of Buena are 9.4 +/- 3.4 mBq g(ash)(-1) for 238U, 9.2 +/- 4.0 mBq g(ash)(-1) for 234U, 7.0 +/- 4.2 mBq g(ash)(-1) for 232Th, 256.1 +/- 134.6 mBq g(ash)(-1) for 228Th, 335.5 +/- 192.8 mBq g(ash)(-1) for 228Ra, 156.6 +/- 74.1 mBq g(ash)(-1) for 226Ra and 66.7 +/- 17.7 mBq g(ash)(-1) for 210Pb. The results were compared with background concentrations from faecal samples from individuals living in Rio de Janeiro City. For most of the radionuclides analysed, the average concentration in faeces from inhabitants of the high natural radiation background was higher than the concentration found in Rio de Janeiro, considered a 'normal' background area.

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O presente trabalho apresenta os cromatogramas em camada fina dos óleos essenciais, do extrato etanólico e do extrato diclorometano de folhas de três quimiotipos de Lippia alba. Os quimiotipos foram denominados I, II e III para as diferenças no constituinte majoritário dos seus óleos essenciais: citral, carvona e linalol, respectivamente. O óleo e os extratos foram comparados com padrões de citral, carvona e linalol. Etanol e diclorometano podem ser usados para extração desde que ambos os extratos tenham perfis cromatográficos semelhantes. Não houve nenhuma diferença entre os extratos de folhas frescas e secas. Os resultados mostram uma rápida e eficiente identificação dos três quimiotipos através da cromatografia de camada fina.

The present work shows the thin layer chromatography of the essential oils, the ethanolic extract and the dicloromethane extract obtained from leaves of three chemotypes of Lippia alba. The chemotypes were denominated chemotype I, II and III for the differences in the majoritary compound of their essential oils: citral, carvone and linalol, respectivelly. The oil and the extracts were compared with standards of citral, carvone and linalool. Ethanol and dicloromethane can be used for extraction since both extracts have similar cromathografic profiles. There was no diference between extracts of fresh and dried leaves. The results show a fast and eficcient identification of the three chemotypes by thin layer cromatoghraphy.

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The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. A preliminary survey pilot program, that included six mines in Brazil (two coal mines, one niobium mine, one nickel mine, one gold mine and one phosphate mine), was launched in order to determine the need to control the radioactive exposure of the mine-workers. Our survey consisted of the collection and analysis of urine samples, complemented by feces and air samples. The concentrations of uranium, thorium and polonium were measured in these samples and compared to background data from family members of the workers living in the same dwelling and from residents from the general population of Rio de Janeiro. The results from the coal mines indicated that the inhalation of radon progeny may be a source of occupational exposure. The workers from the nickel, gold and phosphate mines that were visited do not require a program to control internal radiological doses. The niobium mine results showed that in some areas of the industry exposure to thorium and uranium might occur.

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In the Goiânia accident, many individuals suffered external and internal contamination. The screening of internal contamination was done through 137Cs urinary excretion. During the first month after the accident, only in-vitro bioassay procedures were done. Incorporation into the body and committed doses were estimated using age-specific mathematical models correlating these quantities to the 137Cs excreted in urine. The ratio of feces to urine of 137Cs excretion was used to evaluate the effectiveness of the administration of Prussian Blue on removal of 137Cs from the body.

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