Non-destructive characterization of artworks in paper support using spectroscopic techniques

Tese de doutoramento, Física, Universidade de Lisboa, Faculdade de Ciências, 2013The work here presented aims at demonstrating the efficacy of X-ray fluorescence (XRF) with portable setups, sometimes complemented by Raman spectroscopy in providing answers for characterization, conservation and authentication issues related with artworks in paper and parchment support. The work begins with a short section regarding the state of the art on the use of portable XRF and Raman spectroscopy in the study of artworks in paper and parchment support. The suitability of the techniques has already been greatly established, however constant improvements from the technological point of view, grant different capabilities. The work is presented as a group of case studies with the intention of providing answers in three major topics: the application of μ-XRF to the study of discolorations in paper documents and drawings, the study of the pigments used in Namban paper folding screens to accomplish their characterization, dating and authentication and the establishment of methodologies for determining/evaluating the thickness of gold leaf used for gilding. In some of these case studies we were approached by conservators who had specific demands and then we pursued similar artworks to improve the corpus of study. The most remarkable aspect of these studies is that all XRF analyses were performed in situ and when there was need for complementary information micro-samples were collected for Raman analysis. This way, the main goals in Cultural Heritage studies were obtained: the artworks were not damaged nor removed from their original location.Fundação para a Ciência e a Tecnologia (FCT, PhD grant SFRH/BD/60778/2009

Fostering collaboration in kindergarten through an augmented reality game

Kindergarten children are a very special class of users, since they are in a primary stage of life, when they must learn how to live in society, e.g. to listen and respect the others’ opinions, share the same objects and also help each other. This study presents an Augmented Reality game, in which kinder garten children were able to collaborate in a spontaneous way supported by motivation, enjoyment and curiosity. This game allows children to explore concepts like the animals and the en vironments they live in by using Augmented Reality markers and a wooden board. These markers are the game pieces and through them children are able to manipulate 3D virtual models. Experiments were performed with several classes of students in different schools. Results suggest that the game is effective in maintaining high levels of motivation and collaboration among children, particularly when using immediate feedback.info:eu-repo/semantics/publishedVersio

A Case Study

This research was funded by FCT-Fundação para a Ciência e a Tecnologia, Portugal, grant number UID/FIS/04559/2020. Publisher Copyright: © 2023 by the authors.Micrometric 2D mapping of distinct elements was performed in distinct soil grain-size fractions of a sample using the micro-X-ray Fluorescence (µ-XRF) technique. The sample was collected in the vicinity of São Domingos, an old mine of massive sulphide minerals located in the Portuguese Iberian Pyrite Belt. As expected, elemental high-grade concentrations of distinct metals and metalloids in the dependence of the existent natural geochemical anomaly were detected. Clustering and k-means statistical analysis were developed considering Red–Green–Blue (RGB) pixel proportions in the produced 2D micrometric image maps, allowing for the identification of elemental spatial distributions at 2D. The results evidence how elemental composition varies significantly at the micrometric scale per grain-size class, and how chemical elements present irregular spatial distributions in the direct dependence of distinct mineral spatial distributions. Due to this fact, elemental composition is more differentiated in coarser grain-size classes, whereas griding-milled fraction does not always represent the average of all partial grain-size fractions. Despite the complexity of the performed analysis, the achieved results evidence the suitability of µ-XRF to characterize natural, heterogeneous, granular soils samples at the micrometric scale, being a very promising investigation technique of high resolution.publishersversionpublishe

In vitro polarized Raman analysis for the evaluation of the efficacy of CPP-ACP remineralizing mousse in tooth hypomineralization

UID/FIS/ 04559/2020The purpose of this in vitro study is to evaluate the efficacy of a commercially available tooth mousse in the remineralization of human enamel in cases of Molar-incisor-hypomineralization (MIH). Treatment protocol with GC Tooth Mousse containing Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) was applied to 12 teeth (4 healthy, 4 hypomineralized with white opacities and 4 hypomineralized with yellow opacities) and the samples were evaluated with polarized Raman microscopy. The depolarization ratio of the symmetric stretching band of phosphate band was compared in each sample before and after treatment with the tooth mousse. The mean depolarization ratio values decreased in all three groups, after the treatment protocol, with significant differences (p < 0.05) for the two hypomineralized teeth’ groups. These results allowed us to conclude that there was an improvement in mineral density and organization of the hypomineralized enamel after treatment with CPP-ACP tooth mousse.publishersversionpublishe

Evaluation of the Efficacy of CPP-ACP Remineralizing Mousse in MIH White and Yellow Opacities—In Vitro Vickers Microhardness Analysis

Funding Information: This research was funded by Fundação para a Ciência e Tecnologia (FCT) (Portugal) by the research center grant UID/FIS/04559/2021 to LIBPhys from the FCT/MCTES/PIDDAC, Portugal. This research was also funded by Cuf, SA by Inês Cardoso-Martins PhD scholarship. Publisher Copyright: © 2022 by the authors.Remineralization of tooth enamel can be partially achieved by the application of a casein phosphopeptides and amorphous phosphate (CPP-ACP) complex. However, evidence to support its effectiveness in Molar-incisor-hypomineralization (MIH)-affected teeth is scarce. The study’s aim is to evaluate the efficacy of CPP-ACP mousse in remineralizing MIH-affected enamel using a Vickers microhardness test. Two groups of enamel opacities of hypomineralized permanent teeth, white (group A) and yellow (group B) lesions (n = 14), went through a 28-day treatment protocol with GC Tooth Mousse. Before and after treatment, microhardness was measured in three different areas of each tooth (hypomineralized, transition, and outside the hypomineralized area). Data were analyzed using parametric and non-parametric tests with a significance of p < 0.05. The mean microhardness values increased in the hypomineralized and transition areas in both groups after the treatment protocol (in group A, 105.38 ± 11.70 to 158.26 ± 37.34; 123.04 ± 22.84 to 156.33 ± 35.70; in group B, 108.63 ± 14.66 to 143.06 ± 22.81; 132.55 ± 20.66 to 146.00 ± 12.88) and the differences pre/post-treatment were statistically significant within each group (p < 0.001 for both groups). Between groups, there was a statistically significant difference in the same areas (hypomineralized: p = 0.003; transition: p = 0.008) with a higher improvement in enamel hardness in group A. Topical application of CPP-ACP showed an increase in the physical strength of the hypomineralized and transition areas of MIH-affected enamel, likely due to an increase in mineral content.publishersversionpublishe

Monte Carlo simulation of portable XRF setup: Non-invasive determination of gold leaf thickness in indo-Portuguese panel paintings

S. Pessanha, M. Manso and V. Antunes also acknowledge FCT for the post-doc grants SFRH/BPD/94234/2013, and SFRH/BPD/103315/2014In this work, we present the combined use of in situ X ray Fluorescence spectroscopy and Monte Carlo simulation using PENELOPE code for the completely non-invasive determination of gold leaf thickness in artworks using lead white as mordant. The methodology used is based on the detection of different characteristic lines of Pb in the X ray fluorescence spectra, attenuated trough the gold leaves, and determining the thickness of gilding by comparing their attenuation. Firstly, this methodology was calibrated using model samples of simple stratigraphy, namely pure Au leafs of 1, 2 and 2.5 μm thickness covering a Pb infinitely thick sheet. The modelled X ray setup was then used to study the gilding thickness of three panel paintings belonging to the Museum of Christian Art in Old Goa (India): two paintings, from the 18th century, concerning to the same series but different themes: Our Lady of Sorrows (MoCA1) and Our Lady of Seven Sorrows (MoCA2), and a third painting entitled Monstrance (MoCA3), from the 17th century. These panel paintings were analyzed to understand the differences and similarities between techniques, according to the time/epoch and technique of its manufacture. The obtained values for MoCA2 tend to be slightly lower than for MoCA1, however, the t student test revealed that the differences were not statistically different (p = .37). Regarding the MoCA3 painting, the average thickness was determined to be statistically different (p < .001) and higher than for the other two paintings. These results emphasize the use of different techniques concerning gold leaf beating. In the 17th century painting it was verified the use of a thicker gold leaf while in the group of the 18th century gold leaf was thinner and manufactured with a similar thickness in both paintings. These results are in consonance with the accuracy of leaf beating technology, increasing with the experience acquired during the ages.authorsversionpublishe

The Dual Paradigm of Mining Waste: “From Ecotoxicological Sources to Potential Polymetallic Resources” - An Example from Iberian Pyrite Belt (Portugal)

GeoBioTec/NOVA UIDP/GEO/04035/2020The main goal of this study was to identify potential chemical elements present in three types of polymetallic mine waste, stored in the old mine site of São Domingos, located in the Iberian Pyrite Belt, Alentejo, Southern Region of Portugal. This study involves the characterization of potential resources in those mine residues, bearing in mind that its reprocessing can facilitate the environmental remediation and rehabilitation activities which are underway at the site. X-ray Fluorescence (XRF) and micro (μ)-XRF 2D mapping surveys were performed. Univariate and multivariate data analysis reveal that differences in compositions are mainly related with element concentration per type of waste. Image processing and clustering analysis allowed the recognition of distinct elemental spatial distribution patterns. Some of these residues, although classified as archeological-industrial heritage materials may present toxicity to the ecological environment and to human health. This fact enhances, therefore, geoethical doubts regarding its remining and exploitability. In this context, a multi-criteria decision analysis considering two geoethical alternatives was performed.publishersversionpublishe

Exploring High-Resolution Chemical Distribution Maps of Incompatible and Scarce Metals in a Nepheline Syenite from the Massif of “Serra de Monchique” (Portugal, Iberian Peninsula)

Funding Information: This research was funded by FCT-Fundação para a Ciência e a Tecnologia, Portugal, grants number UIDB/04035/2020, and UID/FIS/04559/2020. Publisher Copyright: © 2022 by the authors.In this case study, 2D micro energy dispersive X-ray fluorescence (µ-EDXRF) surveys were performed in the nepheline syenite (NS) of “Serra de Monchique” located in the southwest region of Portugal (Algarve, Iberian Peninsula). The results allow the identification in the mineral matrix of certain elements classified as critical raw materials (CRMs). Due to substitution effects, some scarce transition elements, such as Zn and Ni, are present and camouflaged in alkali silicate minerals, while others, such as Co, are included in ferromagnesian mineral phases. As expected, incompatible elements are preferably distributed on the surface of aluminosilicate mineral phases such as Rb and Ga, or exclusively in K-bearing feldspar phases, as it is the case of Sr. Interesting CRMs such as Ti, Zr, and Nb are well individualized in oxides, as well as in sphene and apatite. The detected antagonistic chemical distribution between Ti and Fe, and the good spatial relation between Ti and Ca confirms that Ti is present as sphene and, in areas with absent Si, probably occurs as rutile. Nb has a distribution pattern quite similar to Zr and occurs due to substitution effects. It was possible to conclude that there is probable co-existence of Zr-REE-Nb in specific mineral phases such as apatite, zircon, and other Zr-oxides. These results evidence and confirm NS as a potential source of multiple industrial minerals and distinct scarce elements which are incorporated in oxide or phosphate phases that can be more effectively separated in the beneficiation process.publishersversionpublishe

A non-destructive X-ray fluorescence method of analysis of formalin fixed-paraffin embedded biopsied samples for biomarkers for breast and colon cancer

Authors acknowledge Centro Hospitalar Barreiro-Montijo for allowing the current investigation and providing the samples. Publisher Copyright: © 2023 The AuthorsIn this work we present a methodology for the non-destructive elemental determination of formalin-fixed paraffin-embedded (FFPE) human tissue samples based on the Fundamental Parameters method for the quantification of micro Energy Dispersive X Ray Fluorescence (micro-EDXRF) area scans. This methodology intended to overcome two major constraints in the analysis of paraffin embedded tissue samples – retrieval of optimal region of analysis of the tissue within the paraffin block and the determination of the dark matrix composition of the biopsied sample. This way, an image treatment algorithm, based on R® tool to select the regions of the micro-EDXRF area scans was developed. Also, different dark matrix compositions were evaluated using varying combinations of H, C, N and O until the most accurate matrix was found: 8% H, 15% C, 1% N and 60% O for breast FFPE samples and 8% H, 23% C, 2% N and 55% O for colon. The developed methodology was applied to paired normal-tumour samples of breast and colon biopsied tissues in order to gauge potential elemental biomarkers for carcinogenesis in these tissues. The obtained results showed distinctive biomarkers for breast and for colon: there was a significant increase of P, S, K and Fe in both tissues, while a significant increase of Ca an Zn concentrations was also determined for breast tumour samples.publishersversionpublishe