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.
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.
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•Physics analysis of Particle induced gamma-ray emission was used to measure F levels.•Exposure of F in the pre and postnatal period promotes alteration in the alveolar bone.•The exposure to F affected the organic bone matrix content, mainly type I collagen.•Indirect exposure to F causes changes in the alveolar bone of the offspring.
Francisco Pacheco (1564–1644) was one of the most important Spanish painters, the author of the famous treatise Art of Painting, and a founder of Seville art school. His painting La Inmaculada (1610) ...forms part of the important art collection in the Archbishop’s Palace in Seville and represents the first realization of a new iconography, established by Pacheco. Later, he carried out several paintings with the same subject which are today in different collections. As part of a larger project, La Inmaculada was recently restored and analysed. The characterization of materials and painting procedures was carried out applying noninvasive in situ analysis by ultraviolet fluorescence (UVF), infrared reflectography (IRR), and X-ray fluorescence spectrometry (XRF). Results revealed many retouches, probably from different periods, as well as some pentimenti in the composition. Chemical analysis indicates a preparation made of Seville clay, lead white and some calcite on an animal glue layer, according to Pacheco’s own treatise, and a corresponding pigment palette for the 17th century: lead white, yellow and red earths, lead–tin yellow, vermilion, azurite, smalt, a copper-based green, umber, and bone black. Furthermore, modern pigments such as titanium and zinc whites, chrome green, and cadmium yellow were also identified as results of later interventions.
The Archbishop’s Palace of Seville harbours an important art collection with mostly works by great Renaissance and Baroque artists. However, the authorship of some paintings is unknown, and, in a few ...cases, there is an interest in discovering the painter due to the quality of the artwork. As a first step for this purpose, a systematic analysis procedure has been established using non-destructive techniques, such as UV photography and IR reflectography, to locate interventions and underpaintings, as well as X-ray fluorescence to identify original pigments and those of later interventions. The study following this established protocol is presented with the example of two paintings by unknown authors. They were made in different centuries representing, consequently, different styles. UV images showed several retouches, while IR reflectography revealed under-drawing and composition corrections (pentimenti). Furthermore, XRF identified the pigments applied in the production of the different colours and tonalities, allowing to characterise the artist’s palette, whose pigments generally agree with the dates when the artworks were produced. This study resulted in valuable information on painting materials and techniques, which will be useful in the search for authorships, among others.
The application of X-ray Fluorescence (XRF) analysis in a non-invasive manner on ancient silver coins may not provide reliable bulk compositional data due to possible presence of a surface, silver ...enriched layer. The present work proposes a set of three complementary analytical methodologies to assess and improve the reliability of XRF data in such cases: a) comparison of XRF data on original and cleaned micro-spots on coin surface, b) Ag K/L ratio test and c) comparison of experimental and theoretically simulated intensities of the Rayleigh characteristic radiation emitted from the anode.
The proposed methodology was applied on 82 silver coins from the collection of Ioannes Demetriou, donated to the Numismatic Museum of Athens in the 1890s. The coins originate from different mints and are attributed to the first five Ptolemaic kings' reign (321–180
B.C.). They were analyzed in-situ by using a milli-probe XRF spectrometer.
The presence of an Ag-enriched layer was excluded for the majority of them. The silver fineness was found to be high, with very low concentrations of copper and lead. The composition data provide important information about possible sources of silver during the Ptolemaic period and indications of a gradual coinage debasement after 270
B.C. due to economic or technical reasons.
Juan Martínez Montañés was one of the most important sculptors and altarpiece architects of the Spanish Golden Age. The restoration of the Santa Clara church in Seville has presented a unique ...opportunity to study the main altarpiece, crafted by Montañés between 1621 and 1623. He was also in charge of the polychromy and gilding, believing that delegating these procedures to others would diminish the quality of his work. This conviction led to a well-known lawsuit with the renowned contemporary Spanish painter Francisco Pacheco. Ultimately, the painter and sculptor Baltasar Quintero performed the polychromy of this altarpiece, but under the strict conditions of Montañés. Various non-invasive analytical techniques, such as CT, UVF, XRF, and digital microscopy, were employed to study wood treatment and polychromy. Additionally, three samples were prepared as cross-sections and analysed by SEM-EDX. The results revealed Montañés’ meticulous woodwork, anticipating its long-term preservation. Consistent with Montañés’ commitment to maintaining the superior quality of his work, the analysis showed an absence of a ground layer in the flesh areas, while the gilding was executed with high-quality gold. The pigment palette corresponds to the treaties and documents of his time, and the extensive areas of later retouches were accurately located. These new data provide a deeper understanding of both the technique and the high standards of one of the most important and globally recognised sculptors.
Summary
Employing genetic transformation using an Atcys‐3A cDNA construct expressing the cytosolic O‐acetylserine(thiol)lyase (OASTL), we obtained two Arabidopsis lines with different capabilities ...for supplying cysteine under metal stress conditions. Lines 1‐2 and 10‐10, grown under standard conditions, showed similar levels of cysteine and glutathione (GSH) to those of the wild‐type. However, in the presence of cadmium, line 10‐10 showed significantly higher levels. The increased thiol content allowed line 10‐10 to survive under severe heavy metal stress conditions (up to 400 µm of cadmium in the growth medium), and resulted in an accumulation of cadmium in the leaves to a level similar to that of metal hyperaccumulator plants. Investigation of the epidermal leaf surface clearly showed that most of the cadmium had accumulated in the trichomes. Furthermore, line 10‐10 was able to accumulate more cadmium in its trichomes than the wild‐type, whereas line 1‐2 showed a reduced capacity for cadmium accumulation. Our results suggest that an increased rate of cysteine biosynthesis is responsible for the enhanced cadmium tolerance and accumulation in trichome leaves. Thus, molecular engineering of the cysteine biosynthesis pathway, together with modification of the number of leaf trichomes, may have considerable potential in increasing heavy metal accumulation for phytoremediation purposes.
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