Elemental composition of vegetables cultivated over coal-mining waste

ABSTRACT We assessed elemental composition of the liver in mice subjected to one-time or chronic consumption of the juice of vegetables cultivated in a vegetable garden built over deposits of coal waste. Lactuca sativa L. (lettuce), Beta vulgaris L. (beet), Brassica oleracea L. var. italica (broccoli) and Brassica oleracea L. var. acephala (kale) were collected from the coal-mining area and from a certified organic farm (control). Elemental composition was analyzed by particle-induced X-ray emission (PIXE) method. Concentrations of Mg, S, and Ca of mice subjected to one-time consumption of broccoli and concentrations of these same elements plus Si of mice receiving kale were higher in the coal-mining area. Concentrations of P, K, and Cu were increase after chronic consumption of lettuce from the coal-mining area, whereas the levels of Si, P, K, Fe, and Zn were higher in the group consuming kale from the coal-mining area. Our data suggests that people consuming vegetables grown over coal wastes may ingest significant amounts of chemical elements that pose a risk to health, since these plants contain both essential and toxic metals in a wide range of concentrations, which can do more harm than good.

Análisis químico elemental y de fases por medio de PIXE, DSC, TGA y DRX en MTA Angelus® y un cemento Portland blanco / Elemental chemical composition and phase analysis by means of PIXE, DSC, TGA, and DRX of MTA Angelus® and a white Portland cement

Resumen: El mineral trióxido agregado (MTA) es un cemento usado principalmente para sellar perforaciones en órganos dentales debido a que endurece en presencia de humedad, está compuesto por cemento Portland y trióxido de bismuto. Objetivo: Analizar y comparar por medio de PIXE, DSC, TGA y DRX la composición química elemental y de fases del cemento MTA Angelus® y de un cemento Portland blanco (CPB-CA). Material y métodos: MTA Angelus® blanco y un cemento Portland blanco fueron analizados con PIXE en un acelerador de partículas; el análisis de fases cristalinas se realizó por medio de DRX y contrastado los picos con los de base de datos del ICDD, el DSC se realizó en un calorímetro hasta 900 °C. Resultados: PIXE detectó como elementos de mayor porcentaje fueron aluminio, silicio y calcio para ambos cementos; habiendo diferencias en los porcentajes de azufre; el bismuto sólo se detectó en MTA Angelus®. Se detectaron como elementos traza cobre y estroncio en el MTA Angelus®, además de zirconio en CPB-CA. La relación entre silicio-calcio y silicio-aluminio en los dos cementos es similar. Se identificaron tres fases cristalinas en ambos cementos, silicato dicálcico, silicato tricálcico y aluminato tricálcico; sin embargo, se identificó Bismita en el MTA Angelus® y sulfato de calcio en forma de yeso en CPB-CA, que se logró corroborar con la ayuda de la técnica DSC. Conclusiones: Se logró observar la baja cantidad de yeso en MTA Angelus® por medio de la calorimetría. Tanto las fases cristalinas como la composición química elemental son similares en ambos cementos.

Abstract: Mineral trioxide aggregate (MTA) is a cement mainly used to seal tooth perforations; this is due to the fact that it hardens when in presence of humidity. It is composed of Portland cement and Bismuth trioxide. Objective: To analyze and compare with PIXE, DSC, TGA and DRX elementary chemical and phase composition of MTA Angelus® cement with a white Portland cement (WPC). Material and methods: MTA Angelus® white and a white Portland cement were analyzed with PIXE in a particle accelerator, phase analyses were conducted with XRD contrasting peaks with those in the ICDD database. DSC was conducted in a calorimeter up to 900 oC. Results: PIXE detected the following as greater percentage elements: aluminum, silica and calcium for both cements. Differences were found with sulfur percentages; Bismuth was only detected in MTA Angelus®. Trace elements of copper and strontium were detected in MTA Angelus® and zirconium in WPC. Relationship between silica-calcium and silica-aluminum was similar in both cements. In both cements, three crystalline phases were detected: dicalcium silicate, tricalcium silicate and tricalcium aluminate. Nevertheless, Bismite was identified in MTA Angelus® and calcium sulfate in the form of gypsum in WPC, this was corroborated with DSC technique. Conclusions: In MTA Angelus®, low gypsum amounts were observed by means of calorimetry. In both cements, crystalline phases and elemental chemical composition were similar.

External pixe – A novel approach for determining trace elements in fermentation process.

External Particle Induced X-ray Emission technique was employed in the study of submerged fermentation of ethanol from Jaggery using Saccharomyces cerevisiae as the organism. Effect of KNO3 as a nitrogen source was studied and the uptake of the supplement was monitored. A Proton beam of 3MeV from the 3MV Tandom type pelletron accelerator was used for the multi-elemental analysis. Apart from K, other elements like Cr, Fe, Cu and Zn were identified. The sensitivity of the technique was also determined by varying the sample size between 2mm and 10mm.

Trace elemental analysis of dental caries in human teeth by external pixe.

The elemental profiles of the dental caries in human teeth were analyzed by the external proton induced X-ray emission (External PIXE) studies. A total of ten elements including trace namely P, Ca, V, Mn, Fe, Cu, Zn, As, Sr and Pb were estimated in the present study. P and Ca were found to be the major elements whereas all other elements were in trace level. It was observed that the concentration of elements Phosphorus and Calcium varied between the range 7.98% and 19.26% and 19.83% and 35.2% respectively in dental caries.

Use of PIXE analysis to study urban atmospheric aerosols from downtown Havana City / Aplicación del análisis PIXE al estudio de aerosoles atmosféricos urbanos en el centro de Ciudad de La Habana

ABSTRACT The present work shows the results of a first study aimed at determining the elemental composition in airborne particulate matter (in fine and coarse particle size fractions). It was collected at the Atmospheric Monitoring Station in the Municipality of Centro Habana, using the Particle Induced Xray Emission (PIXE) technique. At present, there is no information available about elemental contents in airborne particulate matter from this region. For this study, we carried out a sampling campaign during five months (November 14, 2006 to April 19, 2007). The samples were collected every second day during 24 h under an air flux of 20 l/min. The air sampler used was a Gent Sampler equipped with a Stacked Filter Unit (SFU) system which allows the aerosol collection in both size fractions simultaneously. A total of 144 aerosol samples were collected (72 correspond to the fine mass particle and 72 to the coarse mass particle). For PIXE analysis, the samples were irradiated by 2.0 MeV energy protons from the 2 MV Tandetron Accelerator from the Laboratory of PIXE analysis at ININ, Mexico. A total of 14 elements (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb) were consistently detected in both of particle size fractions with minimum detection limits in the range of 1-10 ng/ . The quantitative results obtained from PIXE elemental analysis for mass of particles in both fractions have revealed important information that has been used in a first attempt to understand and characterize the atmospheric pollution in this area. A general discussion about these results is presented in this paper.

RESUMEN El presente trabajo reporta los resultados de un primer estudio realizado para determinar la composición elemental en material particulado atmosférico (en tamaños de partícula fina y gruesa) colectado en la Estación de Monitoreo Ambiental del Instituto Nacional de Higiene y Epidemiología, del Municipio de Centro Habana, utilizando la técnica PIXE (emisión de rayos X inducida por partículas). Para este estudio se realizó una campaña de muestreo durante cinco meses, entre los meses de noviembre, 2006 y abril, 2007, con un período de colección de una toma cada segundo día y 24 horas de duración. Se utilizó un muestreador de aire del tipo Gent con posibilidades de colectar de forma simultánea el material particulado fino y grueso. Un total de 144 muestras de MPA se colectaron para este estudio (72 de fracción fina y 72 de fracción gruesa). Las muestras se irradiaron tras la incidencia de un haz de protones de 2,5 MeV. Un total de 14 elementos (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br y Pb) fueron consistentemente detectados en la mayoría de las muestras, con límites mínimos de detección entre 1-10 ng de partículas/ de aire. Los resultados del análisis PIXE para ambos tamaños de partícula revelaron una importante información que se ha utilizado en una primera intención para entender y caracterizar la contaminación atmosférica del área muestreada. Se presenta una discusión general de estos resultados en este trabajo.

Microanálisis de capas pictóricas en esculturas policromadas / Microanalysis of pictorial layers in polychrome sculptures

RESUMEN Se analizan muestras de secciones transversales de esculturas en madera policromadas por los métodos de microanálisis: Microscopía óptica, las técnicas nucleares: microfluorescencia de rayos X y microemisión de rayos X inducida por protones con sistema de detección por dispersión de Rutherford acoplado y el método tradicional de Microscopía Electrónica de Barrido con detección de fluorescencia de rayos X dispersiva en energía acoplada. Se enfatiza en la microfluorescencia de rayos X por ser un método novedoso a partir del desarrollo alcanzado en la óptica de rayos X y que se puede implementar en un sistema convencional de FRX. Los resultados se comparan en cuanto a resolución espacial para diferenciar la estructura de capas pictóricas y sensibilidad elemental. Se determinaron el número de capas, su posición relativa, su espesor y la composición química de los pigmentos para caracterizar valiosas policromías de la otrora iglesia habanera San Juan de Letrán con el objetivo de obtener información acerca de la "historia materia"; que deba contribuir a su investigación de procedencia y atribución. Los pigmentos usados en esta obra artística se identificaron por los elementos característicos. Los mapas de distribución elemental obtenidos por las técnicas nucleares usadas, reproducen exactamente las estructuras observadas en las fotomicrografías obtenidas por medio de la microscopía de luz.

ABSTRACT Cross section samples from polychrome wood sculpture are analyzed by optical microscopy, the nuclear techniques: micro-X Ray Fluorescence, micro- Proton induced X-ray Emission coupled with Rutherford Backscattering and the traditional method by Scanning Electronic Microscopy with Energy Dispersive X-ray fluorescence detection (SEM-EDX) micro-analytical methods. Special emphasis is dedicated to µXRF, a novel advanced technique developed thanks to the last achievements of the X-ray optics that can be available by modifying conventional laboratory XRF spectrometer, representing an alternative to the traditional and expensive SEM-EDX stratigraphic analysis of pictorial works. The results are compared with respect to spatial resolution to differentiate pictorial layer structure and elemental sensitivity. Number of layer, relative position of layer, layer thickness and chemical composition of pigments are determined in the characterization of valuable polychromies of once church San Juan de Letrán in order to obtain information about their "material history" that should contribute to its provenance and attribution research. The pigments used in this artistic works were identified by their characteristic elements. The elemental distribution maps obtained by the used nuclear techniques precisely reproduced microphotographies obtained by means of Light Microscopy.