Characterization of irradiation channels in the carousel of TRIGA Mark I IPR-R1 research reactor, Brazil, aiming at the application of k 0-standardization method of neutron activation analysis.

New values of neutron fluxes and spectral parameters f and α were determined experimentally in all irradiation devices of the TRIGA Mark I IPR-R1 nuclear research reactor at Nuclear Technology Development Centre (CDTN), Belo Horizonte, Brazil. Sets of monitors Au, Fe, Zn and Zr were irradiated bare and Cd-covered, according to "Cd-ratio for multi-monitor" method. Values were validated by analysing the certified reference material BCR-320R irradiated in chosen channels. The calculations were made based on irradiation channel values and the average values of the Carousel. The results of E n -score point out that the k 0-method is producing reliable results. From now on, the values of mass fractions in several matrices, the production and studies with radioisotopes will be more accurate and the activities calculated more precisely.

Arsenic in Sediments, Soil and Plants in a Remediated Area of the Iron Quadrangle, Brazil, and its Accumulation and Biotransformation in Eleocharis geniculata.

Since arsenic (As) exposure is largely due to geochemical contamination, this study focused on the remediated area of Santana do Morro, a district of Santa Bárbara, Minas Gerais, Brazil, which was previously contaminated with As due to gold mining. Total As concentrations in sediment, soil and plants were determined, next to As species, anionic arsenic compounds As(III), As(V), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), in plants samples. Total As concentrations in soil and sediments were slightly elevated (16-18 µg g-1) and most of the plants contained low levels of As (< 1 µg g-1). The exception was a native plant Eleocharis geniculata (L.) which contained elevated levels of As (4 µg g-1). The exposure of this plant to As under controlled conditions (hydroponics) indicated its possible tolerance to elevated As levels and suggesting its potential use in phytomonitoring of As-contaminated sites. This plant is able to metabolize arsenate to arsenite and contained MMA and DMA, both in its natural habitat and under controlled conditions.

Proposed design for the PGAA facility at the TRIGA IPR-R1 research reactor.

BACKGROUND: This work presents an initial proposed design of a Prompt Gamma Activation Analysis (PGAA) facility to be installed at the TRIGA IPR-R1, a 60 years old research reactor of the Centre of Development of Nuclear Technology (CDTN) in Brazil. The basic characteristics of the facility and the results of the neutron flux are presented and discussed. FINDINGS: The proposed design is based on a quasi vertical tube as a neutron guide from the reactor core, inside the reactor pool, 6 m below the room's level where shall be located the rack containing the set sample/detector/shielding. The evaluation of the thermal and epithermal neutron flux in the sample position was done considering the experimental data obtained from a vertical neutron guide, already existent in the reactor, and the simulated model for the facility. METHODS: The experimental determination of the neutron flux was obtained through the standard procedure of using Au monitors in different positions of the vertical tube. In order to validate both, this experiment and calculations of the simulated model, the flux was also determined in different positions in the core used for sample irradiation. The model of the system was developed using the Monte Carlo code MCNP5. CONCLUSION: The preliminary results suggest the possibility of obtaining a beam with minimum thermal flux of magnitude 10(6) cm(-2) s(-1), which confirm the technical feasibility of the installation of PGAA at the TRIGA IPR-R1 reactor. This beam would open new possibilities for enhancing the applications using the reactor.

Plasma zinc and hair zinc levels, anthropometric status and food intake of children in a rural area of Brazil / Zinco plasmático e zinco capilar, antropometria e consumo alimentar de crianças em uma região rural do Brasil

OBJECTIVE: The objective of this study was to investigate the levels of plasma zinc, hair zinc, growth and food consumption in children aged 6 to 24 months in a rural area of Diamantina (MG), Brazil. METHODS: Plasma and hair zinc concentrations were analyzed using flame atomic absorption spectrometry and neutron activation analysis, respectively. Weight-for-age, weight-for-height and height-for-age, expressed as Z-scores, were measured according to the World Health Organization reference curves. Dietary zinc intake was determined by a 3-day dietary recall filled out by the mother or guardian. RESULTS: Zinc deficiency was found in 11.2 percent and 16.8 percent of the children according to plasma zinc e hair zinc levels, respectively. Mean plasma zinc and hair zinc for children <11 (49) and >11 (127) months of age were 15.4 (SD=4.2) µmol L-1 and 139.5 (SD=72.1) µg g-1 and 16.0 (SD=4.5) µmol L-1 and 134.3 (SD=110.3) µg g-1, respectively. Anthropometric measurements showed that 8.0 percent, 6.8 percent and 3.4 percent of the children were underweight, stunted and wasted, respectively. The mean dietary intake of zinc was 3.2 (SD=2.3) mg/day. One-third of the children did not eat enough foods that contain zinc. There were no correlations among plasma zinc level, hair zinc level, anthropometric parameters and zinc intake. CONCLUION: The results demonstrate that zinc deficiency is a problem in the studied population, not just in malnourished children. Nutritional care should be provided for this population in order to improve their consumption of high-zinc foods and monitor zinc deficiency.

OBJETIVO: Investigar níveis plasmáticos de zinco, concentração de zinco capilar, crescimento físico, e consumo de zinco em crianças de 6 a 24 meses da região de Diamantina (MG), Brasil. MÉTODOS: As concentrações de zinco plasmático e zinco capilar foram analisadas empregando as técnicas de espectrometria atômica de absorção e de ativação neutrônica, respectivamente. Peso-para-idade, peso-para-altura e altura-para-idade, expressos em escore-Z, foram medidos, de acordo as curvas de referência da Organização Mundial de Saúde. O zinco dietético dos sujeitos foi avaliado a partir de três registros alimentares, preenchidos pelas mães ou responsáveis. RESULTADOS: A deficiência de zinco foi observada em 11,2 por cento e em 16,8 por cento das crianças, segundo os níveis de zinco plasmático e zinco capilar, respectivamente. As médias em crianças com 11 meses ou menos (49) e 11 (127) meses ou mais de idade para níveis de zinco plasmático e zinco em cabelos foram 15,4 (DP=4,2) µmol L-1 e 139,5 (DP= 72,1) µg g-1 e 16,0 (DP= 4,5) µmol L-1 e 134,3 (DP=110,3) µg g-1, respectivamente. Os resultados antropométricos mostraram que 8,0 por cento, 6,8 por cento e 3,4 por cento das crianças foram classificadas com baixo peso, baixa estatura e emagrecidas, respectivamente. A média do consumo dietético de zinco pelas crianças foi de 3,2 (DP=2,3) mg/zinco por dia, e um terço das crianças consumiam alimentos fonte de zinco abaixo do recomendado. Não houve correlação entre as variáveis zinco plasmático, zinco em cabelos, antropometria e consumo de zinco. CONCLUSÃO: Os resultados demonstram que a deficiência de zinco é um problema na população estudada, não somente nas crianças desnutridas. Atenção nutricional deverá ser direcionada a esta população, com o intuito de melhorar o consumo de alimentos ricos neste mineral e monitorar a deficiência de zinco.

Avaliação das concentrações de zinco no aparelho reprodutor feminino por ativação neutrônica instrumental / Assessment of zinc concentration in the female reproductive system by instrumental neutron activation

A esterilização feminina não cirúrgica por meio da aplicação intracervical de pastilhas de cloridrato de quinacrina foi considerada um método contraceptivo definitivo de baixo custo, seguro e eficaz. O zinco, presente no útero e nas tubas uterinas, inibe a ação da quinacrina. A adição de cobre aumenta a eficácia da quinacrina, reduzindo o risco de gravidez devido às falhas de obstrução das tubas uterinas. O cobre neutraliza o efeito deletério do zinco, aumentando a eficácia do método. Para obter o mapeamento da concentração de zinco no aparelho reprodutor feminino, amostras de útero e de tubas uterinas foram analisadas por ativação neutrônica instrumental. Os resultados obtidos são apresentados neste trabalho.

Nonsurgical female sterilization through the transcervical insertion of quinacrine pellets was considered a definitive, low-cost, safe and effective contraceptive method. The zinc, present in both uterus and Fallopian tubes, inhibit the action of quinacrine. The addition of copper increases the efficacy of quinacrine, thus reducing the risk of pregnancy due to the failure to obstruct the Fallopian tubes. The copper neutralized the deleterious effect of the zinc and so the treatment efficacy is increased. In order to obtain a mapping to study the zinc concentration in the female reproductive system, samples of both uterus and Fallopian tubes were analyzed by neutron activation. The results are here reported.

Production of the radioactive antitumoral cisplatin.

This work presents the preparation of radiolabelled cis-dichlorodiammineplatinum (II), CDDP*, sealed in a cadmium capsule. The irradiation of CDDP covered by cadmium, employing exposure times longer than 2 h, demonstrated good chemical purity and high specific activity. This finding allowed a better detection of in vivo CDDP* and suggests that it may be a good tool for studies of long-term biodistribution of pharmaceutical formulations containing this drug.

Use of labelled cisplatin obtained by direct irradiation in a preliminary biodistribution study

This work presents the preparation of radiolabelled cis-dichlorodiammineplatinum (II), CDDP*, from its direct irradiation into a cadmium capsule, using the TRIGA MARK I IPR R-1 research reactor of the CDTN. The ability to detect CDDP* in Ehrlich tumour-bearing mice after administration via an intravenous route was evaluated. After 24 hours, blood and some organs were collected to determine the incorporated activity. The CDDP* showed a great chemical purity and high specific activity that resulted in an optimum in vivo detection. The CDDP* was taken up principally by liver, spleen and kidney. The CDDP* obtained from this condition was shown to be a good tool for biodistribution studies.

O presente trabalho refere-se à obtenção de cis-diclorodiaminoplatina (II) radiomarcada, CDDP*, a partir de sua irradiação direta numa cápsula de cádmio. A irradiação foi realizada no reator de pesquisa TRIGA MARK I IPR R-1. Em seguida, foi avaliada a capacidade de detecção da radioatividade emitida por CDDP* após sua administração intravenosa em camundongos acometidos por tumor de Ehrlich. Após 24 horas, fez-se a coleta de amostras de sangue e de alguns órgãos, a fim de se avaliar o nível de radioatividade presente nos mesmos. A CDDP* obtida apresentou uma ótima pureza química e elevada atividade específica que permitiu um excelente nível de detecção. A CDDP* foi captada principalmente pelo fígado, baço e rins. Portanto, a CDDP* obtida na condição de bombardeamento supracitada mostrou ser uma ferramenta útil para a realização de estudos de biodistribuição.

Study of essential elements in cattle tissues from a tropical country using instrumental neutron activation analysis.

There has been increasing interest in the elemental composition of animal tissues to support health and nutritional studies. Determining the elemental concentration in cattle tissues is especially important because these materials are used for multipurpose objectives such as the assessment of animal health, the quality of human foods consumed, and as a potential environmental biomonitor. Chromium, copper, sodium, potassium, iron, and zinc levels were determined in bovine tissues--kidney, liver and muscle--from cattle bred and raised in a potentially metal contaminated region because of mineral activities. The Brazilian data were obtained using k0-instrumental neutron activation analysis, performed at the Nuclear Development Technology Centre/Nuclear Energy National Commission (CDTN/CNEN) in Minas Gerais State. The values of international organizations and the Brazilian analytical data are compatible. This study indicates that the nuclear technique is an efficient tool to determine elemental concentration in animal biological samples.