Determination of gold leaf thickness using X-ray fluorescence spectrometry: Accuracy comparison using analytical methodology and Monte Carlo simulations.

In this work, we compared the accuracy of gold leaves thickness determination using X-ray Fluorescence (XRF) setups for different X-ray excitation sources. The sources used consisted on: a) direct Bremsstrahlung from an Amptek Mini-X X-ray tube with Rh target, b) partially monochromatized radiation of the same X-ray tube using combination of Al and Ag filters and, c) monochromatic radiation using secondary target, in a portable setup with triaxial geometry. The performance of the used setups was compared using model samples made with gold foil standard reference materials of known thicknesses (1, 2 and 2.5 µm). Thickness determination was based on the selective attenuation that the different energies of a given element of an under-layer undergo in the gilded layer. Ideally, as it can be expected from physics fundamentals, monochromatic radiation is needed for improved accuracy. However, considering the difficulties in using monochromatic radiation in portable instrumentation applicable in Cultural Heritage studies, filtered radiation can also be used for reliable results. Moreover, Monte Carlo simulations of the portable setup with conventional planar geometry were performed for comparison and for future application in more complex samples.

Assessment of Toxic Metals and Hazardous Substances in Tattoo Inks Using Sy-XRF, AAS, and Raman Spectroscopy.

Synchrotron radiation X-ray fluorescence spectroscopy, in conjunction with atomic absorption and Raman spectroscopy, was used to analyze a set of top brand tattoo inks to investigate the presence of toxic elements and hazardous substances. The Cr, Cu, and Pb contents were found to be above the maximum allowed levels established by the Council of Europe through the resolution ResAP(2008)1 on requirements and criteria for the safety of tattoos and permanent makeup. Raman analysis has revealed the presence of a set of prohibited substances mentioned in ResAP(2008)1, among which are the pigments Blue 15, Green 7, and Violet 23. Other pigments that were identified in white, black, red, and yellow inks are the Pigment White 6, Carbon Black, Pigment Red 8, and a diazo yellow, respectively. The present results show the importance of regulating tattoo ink composition.

Microscopy and X-ray spectroscopy analyses for assessment of gilding and silvering techniques of Portuguese illuminated manuscripts.

The objects of this study are various local charters (cartas de foral, in Portuguese) granted by Dom Manuel I, King of Portugal (1495-1521), which substituted for medieval ones and were intended to achieve an administrative unification. These are luxuriously illuminated manuscripts, and our study aims at obtaining a better understanding of the gilding and silvering techniques applied to the parchments, in which the forais were written, between 1500 and 1520. The combined use of microscopy and X-ray spectroscopy analyses allowed us to identify the vestigial materials used for making the parchments, including products such as salt (NaCl), lime (CaO), pumice stone (SiO2+Al2O3), and chalk (CaCO3). Chalk was employed as a whitening agent to give the parchment its final color and opacity. Shell-gold and shell-silver mixed in with animal glue or gum binding media were directly applied on type 1 and 3 forais, while very thin gold leaves (<1 µm) were applied over lead-based tempera grounds (50-180 µm thick) in type 2 forais. Silver was always employed in its finest form without a further protective layer (thus its recursive state of corrosion), while gold was used in various alloy grades.

Total reflection X-ray spectrometry (TXRF) for trace elements assessment in edible clams.

The present contribution presents a preliminary investigation of the chemical composition with respect to major, minor, trace, and ultratrace elements in several clam species that are frequently used for human consumption in Portuguese markets and worldwide. In order to use a simple and rapid analytical methodology for clam analysis, energy dispersive X-ray fluorescence (EDXRF) spectrometry and total reflection X-ray fluorescence (TXRF) spectrometry were selected as analytical techniques. The analytical capabilities of TXRF spectrometry were evaluated for the determination of minor and trace elements in commercial edible clams. We compared the direct analysis of powdered suspensions (using different sample amounts and dispersant agents) with the analysis of the digested samples for trace element determination. Inductively coupled plasma mass spectrometry analysis of clam digests was also performed to evaluate the analytical possibilities of TXRF spectrometry for trace and ultratrace analysis.

From fish chemical characterisation to the benefit-risk assessment--part A.

Proximate composition, fatty acid profile, cholesterol, α-tocoferol content and essential (K, Na, Cl, S, Mg, Ca, Zn, Cu, Fe, Mn, and Se) and contaminant element (Hg/MeHg, Cd, Pb, and As) levels in silver scabbardfish (Lepidopus caudatus), hake (Merluccius merluccius), and ray (Raja spp.) were investigated. Results showed that these species contain high protein, low cholesterol and energy levels, being its consumption recommended. Polyunsaturated fatty acids (PUFA) were the dominant group of the fatty acids, being 80% of the n-3 family. Attending to the dietary reference intakes (DRIs), these fish species are a good source of Se and the other minerals can give a relevant contribution to the DRIs in a balanced diet. More than one weekly meal of silver scabbardfish has to be avoided due to the organic mercury concentration. More accurate dietary recommendations require a probabilistic assessment, which will be the focus of this study's Part B.

Economia de comunhão: responsabilidade social, ideología e representações sociais / Economia de comunion / responsabilidad social, ideologia y representaciones sociales / Communion economy: social responsibility, ideology and social representations

O artigo analisa um caso particular de responsabilidade social - a Economia de Comunhão (EdC) - buscando identificar as representações sociais (Moscovici, 2003) que a constituem e se as mesmas possuem ou não um caráter ideológico (Thompson, 1995). Os dados foram coletados através de visitas a empresas, participação em congressos, pesquisas documental e bibliográfica e a análise realizada a partir da hermenêutica da profundidade (Thompson, 1995). Os resultados indicaram que, através de representações de origem religiosa (lucro como benção divina), de outras já sedimentadas pelo capitalismo (ex. lucro como fruto da competência empresarial) e de representações emergentes (ex. empresário como modelo de ética e competência) a EdC cumpre, ideologicamente, a função de legitimar as mudanças nas relações de trabalho requeridas pelos modelos flexíveis de gestão e suprimir as contradições e conflitos sociais à medida que apresenta o empresário como o grande pai, capaz de oferecer sustento, proteção e afeto a pobres e trabalhadores

The article analyzes a peculiar case of social responsibility - the economy of communion (EdC) - trying to identify the social representations (Moscovici, 2003) that constitute it and whether they possess or not an ideological character (Thompson, 1995). The data were collected through visits to companies, participation in congresses, documental and bibliographical research and the analysis that was accomplished based on the depth hermeneutics (Thompson, 1995). The results indicated that, through representations of religious origin (profit as divine blessing), through other values accepted by capitalism (profit as a result of business competence) and of emerging representations (the entrepreneur as a model of ethics and competence), EdC accomplishes, ideologically, the function of legitimating the changes in the work relationships requested by the flexible models of administration and of suppressing the contradictions and social conflicts in a way that presents the entrepreneur as the great father, capable of offering sustenance, protection and affection to the poor and to the workers.