Zurbarán attribution hypothesis supported by pigment analysis and multiband images observation of four paintings by his workshop.

Francisco de Zurbarán was one of the greatest painters of the Spanish Golden Age, with artworks scattered all over the world. Unfortunately, there are hardly any exhaustive studies on the pigments that he used. In this work, four canvas paintings attributed to the Zurbarán Workshop were studied. Each of them presents the figure of a different saint in a particular isolation scene: Saint Bruno, Saint Francis of Assisi, Saint Dominic of Guzman, and Saint Peter Martyr. Nevertheless, the painting of Saint Peter Martyr shows superior quality in both technique and colours, so it is not clear whether this canvas was also made by the Workshop or by Zurbarán himself, as some art historians claim. Coinciding with conservation and restoration works, the paintings were initially analysed with non-invasive techniques such as ultraviolet photography (UV), infrared reflectography (IRR) and X-ray fluorescence (XRF) to determine the characterization of the pigments. Those studies were complemented by stratigraphic analysis of some extracted samples with optical microscopy (OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Among a number of results obtained, we found significant differences between the pigment palette used in Saint Peter Martyr and the other paintings, supporting the hypothesis that this painting was done by Zurbarán himself instead of his workshop. These results could also help to distinguish other authentic paintings by the master's hand from very similar paintings by his workshop or by other artists.

Fluoride exposure duringintrauterine and lactation periods promotes changes in the offspring rats' alveolar bone.

The importance of fluoride (F) for oral health is well established in the literature. However, evidence suggests that excessive exposure to this mineral is associated with adverse effects at different life stages and may affect many biological systems, especially mineralized tissues. The purpose of this study was to investigate the effects of F exposure during pregnancy and breastfeeding on the alveolar bone of the offspring since the alveolar bone is one of the supporting components of the dental elements. For this, the progeny rats were divided into three groups: control, 10 mg F/L, and 50 mg F/L for 42 (gestational and lactation periods). Analysis of the quantification of F levels in the alveolar bone by particle-induced gamma emission; Raman spectroscopy to investigate the physicochemical aspects and mineral components; computed microtomography to evaluate the alveolar bone microstructure and analyses were performed to evaluate osteocyte density and collagen quantification using polarized light microscopy. The results showed an increase in F levels in the alveolar bone, promoted changes in the chemical components in the bone of the 50 mg F/L animals (p < 0.001), and had repercussions on the microstructure of the alveolar bone, evidenced in the 10 mg F/L and 50 mg F/L groups (p < 0.001). Furthermore, F was able to modulate the content of organic bone matrix, mainly collagen; thus, this damage possibly reduced the amount of bone tissue and consequently increased the root exposure area of the exposed groups in comparison to a control group (p < 0.001). Our findings reveal that Fcan modulate the physicochemical and microstructural dimensions and reduction of alveolar bone height, increasing the exposed root region of the offspring during the prenatal and postnatal period. These findings suggest that F can modulate alveolar bone mechanical strength and force dissipation functionality.

Characterization of Castellani nineteenth-century gold jewellery by in situ micro-XRF spectroscopy.

The material characterization of nineteenth-century artifacts is of great interest, due both to the breakthrough technological advances and to the unprecedented spread of forgeries of antiquities which took place in that period. However, this type of artifacts has been largely overlooked in the past. In this paper we present the compositional analysis of gold jewels by the Castellani, one of the most important families of goldsmiths in nineteenth-century Europe. The use of a portable micro-XRF spectrometer, specifically developed for jewellery analysis at the Centro Nacional de Aceleradores (Seville), allowed us to analyse, in a completely non-invasive way, the alloys, joining techniques and surface treatments of the jewels of the Castellani collection at the National Etruscan Museum of Villa Giulia in Rome. The addition to the spectrometer of a second X-rays detector with a zinc filter allowed us to check the possible presence of low amounts of cadmium, a metal added to gold soldering only from the nineteenth century and often used in authenticity studies. Moreover, the relative intensities of the Au X-ray lines were studied in order to check non-invasively the presence of surface enrichments in gold.