A pilot study on the use of neutron activation analysis and multivariate statistics for the provenance of Jamaican Cannabis sativa L (Marijuana).

The aim of this study was to use instrumental neutron activation analysis and multivariate analysis to determine the provenance of Jamaican Cannabis sativa L. Sixty-three samples were collected from various areas in Jamaica, with no other data but their known or self-reported growing regions. The samples were analysed for Al, As, Br, Ca, Cd, Co, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sb, Sc, Sm, Sr, V, and Zn. The resulting elemental data were statistically evaluated using agglomerative hierarchical cluster analysis and principal component analysis. Cluster analysis was able to group the samples into their known or reported growing regions with a high degree of accuracy. Principal component analysis was also able to elucidate some of the underlying geochemical factors that could explain the clustering. These included the underlying bauxitic geochemistry and the influence of fertilizer inputs. Of the analysed elements, Al, As, Cd, Co, Fe, K, La, Mg, Mn, Sc, Sm, V, and Zn appear to be most significant in identifying the growing regions of the cannabis samples. Results indicate the promise of this methodology with an increased dataset and potentially further refinement of the identifying elements.

Neutron Autoradiography Combined With UV-C Sensitization: Toward the Intracellular Localization of Boron.

Our group has reported the imprint formation of biological material on polycarbonate nuclear track detectors by UV-C exposure, which is used as an approach to simultaneously visualize cell imprints and nuclear tracks coming from the boron neutron capture reaction. Considering that the cell nucleus has a higher UV-C absorption than the cytoplasm and that hematoxylin preferentially stains the nucleus, we proposed to enhance the contrast between these two main cell structures by hematoxylin staining before UV-C sensitization. In this study, several experiments were performed in order to optimize UV-C exposure parameters and chemical etching conditions for cell imprint formation using the SK-BR-3 breast cancer cell line. The proposed method improves significantly the resolution of the cell imprints. It allows clear differentiation of the nucleus from the rest of the cell, together with nuclear tracks pits. Moreover, it reduces considerably the UV-C exposure time, an important experimental issue. The proposed methodology can be applied to study the boron distribution independently from the chosen cell line and/or boron compounds.

Analysis of saliva from Amblyomma cajennense (Acari: Ixodidae)species from Brazil by NAA

The Amblyomma cajennense tick species is considered one of the most important and widespread species in Brazil. It salivary secretion has been a target ofseveral studies in biocenology, as the vector of diseases and in investigations related to antihemostatic properties andantitumor. To complement this investigation, neutron activation analysis (NAA) was applied to determine concentrationsof elements in saliva samples of this tick species. The saliva samples (50–554 lL) were collected at Butantan Institute (São Paulo city, Brazil) and they were investigated using the IEA-R1 nuclear reactor at IPEN/ CNEN-SP-Brazil. These data were compared with the values established for Amblyomma americanum and Amblyomma variegatum species emphasizing agreement only for Cl, K and Na with the A. americanum species,suggesting similarities in the mechanisms that regulate the osmotic pressure in this hematophagous animal. The knowledge of these limits contributes for tick saliva characterization as well as for the understanding of the many physiological processes, especially those related to salivary secretion.

Determination of the neutron spectrum shape parameter alpha in k0 NAA methodology using covariance analysis.

The k(0) method for quantitative reactor neutron activation analysis (NAA) has been applied in several laboratories for the determination of multi-elemental concentrations in different materials. The general formula that yields the concentration value can be divided in two parts: one involving detection parameters and the other involving irradiation parameters. A rigorous uncertainty calculation must take into account the correlations between each of these parameters. The Nuclear Metrology Laboratory at IPEN has a research program intended to develop a methodology applying covariance analysis in order to obtain the overall uncertainty in the concentrations of different elements in a given sample, and the correlation between each pair of them. The present paper concentrates in the determination of the neutron spectrum shape factor alpha by two methods: Cd-covered and Cd-ratio, using experimental data obtained in the IEA-R1 research reactor. The final values for alpha were: (0.001+/-0.018) and (0.001+/-0.019) for the Cd-covered and Cd-ratio methods, respectively, in good agreement with each other.

A comparative neutron activation analysis study of common generic manipulated and reference medicines commercialized in Brazil.

In this work, a comparative study of neutron activation analysis (NAA) was performed by the nuclear institutes: CDTN/CNEN-Brazil, CCHEN-Chile and the SCK.CEN-Belgium aiming to investigate some generic, manipulated and reference medicines largely commercialized in Brazil. Some impurities such as: As, Ba, Br, Ce, Co, Cr, Eu, Fe, Hf, Sb, Sc, Sm, Ti and Zn were found, and the heterogeneity of the samples pointed out the lack of an efficient public system of quality control.

Assessment of atmospheric metallic pollution in the metropolitan region of São Paulo, Brazil, employing Tillandsia usneoides L. as biomonitor.

Tillandsia usneoides L. is an epiphytic bromeliad plant able to absorb water and nutrients directly from the air. For this reason this species was selected to carry out a monitoring study of air pollution in the metropolitan region of São Paulo, Brazil. Five consecutive transplantation experiments (8 weeks each) were performed in 10 sites of the city, submitted to different sources of air pollution (industrial, vehicular), using plants collected from an unpolluted area. After exposure, trace metals were analyzed in the plant by instrumental neutron activation analysis. Traffic-related elements such as Zn and Ba presented high concentrations in exposure sites near to heavy traffic avenues (cars, buses and trucks) and may be associated to vehicular sources. For Zn and Co the highest contents were related to industrial zones and can be associated to the presence of anthropogenic emission sources. The rare earth elements, Fe and Rb, probably have soil particles as main source.

In situ gamma spectroscopy measurement of 41Ar during neutron activation analysis with the SLOWPOKE II reactor in Jamaica.

In situ gamma spectroscopy was used to measure 41Ar released into the laboratory due to the activation of air in the irradiation tubes of SLOWPOKE reactor during routine neutron activation analysis. The data obtained were used to predict the 41Ar distribution in the laboratory for various operating conditions of the reactor. The dose received by the analyst from the immersion in 41Ar was calculated to be 2.36 microSv gamma(-1), which is approximately 1% of the normal background exposure.

Instrumental nuclear activation analysis (INAA) characterization of environmental air filter samples.

Nuclear techniques have been used in quantitations of environmental pollutants, and instrumental neutron activation analysis (INAA) has turned out to be particularly useful in the analysis of airborne suspended particles. This work describes the INAA characterization of the particulate material in the environmental samples obtained in a monitoring campaign in Mexico City's Metropolitan Area. As the types of the irradiation facilities and gamma-ray detection system impose some limitations on the possibilities of INAA analysis, the actual experimental conditions at Gamma Spectroscopy Laboratory, where the analysis was performed, had been assessed. The facilities had been found suitable for the analysis of samples from this campaign, in which 22 elements were determined.

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.

Selenium determination in whole human blood by radiochemical neutron activation analysis: preliminary results in Argentina.

In Argentina there are no values regarding the content selenium in food or its effect on nutritional status. Neutron activation analysis and a radiochemical separation scheme for selenium has been adjusted for blood samples from healthy adult individuals. Fasting whole blood was collected, lyophilized, packed, and irradiated in a nuclear reactor. Selenium was determined by a radiochemical separation. The method was validated using certified reference materials. The selenium concentrations (mean value +/- SD) from five pools and from 22 individual samples were 0.070 +/- 0.020 microgram/ml and 0.071 +/- 0.014 microgram/ml, respectively, ranging between 0.047 to 0.105 microgram/ml. These preliminary results show values close to those published for the population living in areas with adequate selenium intake, but lower values than those published for the USA population. However, it will be necessary to carry out nutritional status studies in other areas of Argentina, taking into account the geographic and topographic diversity of the country.

Explosives detection using prompt-gamma neutron activation and neural networks.

This work describes a study of the application of a neural network to determine the presence of explosives using the neutron capture prompt gamma-ray spectra of the substances as patterns which were simulated via Monte Carlo N-particle transport code, version 4B. After the training of the neural networks, it was possible to determine the presence of the C-4 explosive, even when they were occluded by several materials. The neural network was a powerful tool, able to recognize prompt gamma-ray explosive patterns in spite of the presence of occluding materials. Besides that, the network was able to generalize, identify the presence of explosive in cases in which it had not been trained. In that way, it was revealed as a potential tool for in situ inspection systems.

Shielding design studies for a neutron irradiator system based on a 252Cf source.

This study aims to investigate a shielding design against neutrons and gamma rays from a source of 252Cf, using Monte Carlo simulation. The shielding materials studied were borated polyethylene, borated-lead polyethylene and stainless steel. The Monte Carlo code MCNP4B was used to design shielding for 252Cf based neutron irradiator systems. By normalising the dose equivalent rate values presented to the neutron production rate of the source, the resulting calculations are independent of the intensity of the actual 252Cf source. The results show that the total dose equivalent rates were reduced significantly by the shielding system optimisation.

Neutron activation analysis of Se in bovine plasma samples.

Elemental concentration of selenium in bovine plasma at parts-per-billion levels was determined using radiochemical neutron activation analysis (RNAA). This study was connected with the relation between the Enteque Seco, a toxic bovine calcinosis, and the Se status. The technique developed is based on the coprecipitation of Se with HgS. Good agreement with certified reference materials have been found. The values for the Se contents in normal bovine samples were in concordance with literature values.

Determination of trace elements in aerosol samples by instrumental neutron activation analysis.

Two nuclear techniques, Energy-Dispersive X-Ray Fluorescence Analysis (EDXRF) and Instrumental Neutron Activation Analysis (INAA), were used to analyze aerosol samples collected in the city of São Paulo, Brazil. Na, Cl, Mn, V, Al, Sm, Mo, W, La, As, Br, Sb, K, Ba, Se, Th, Cr, Rb, Ca, Fe, Ce, and Sc were determined by INAA, and Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Hg, and Pb were determined by EDXRF. A preliminary identification of the main source of the atmospheric aerosol was performed based on enrichment factor and correlation coefficient calculations.