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The use of 3-aminopropyltriethoxy silane (APS) as inorganic precursor in the synthesis of hybrid materials in substitution of traditional alkoxides such as tetraethylorthosilicate (TEOS), opens up the possibility of incorporate reactive amine groups into the three-dimensional network. These groups can be used in order to link different organic compounds to the material. On the other hand, the short times of APS hydrolysis, allow to work under very soft conditions, such us non acid media and room temperature, hence avoiding the decomposition of the organic active compounds. The aim of this work is the synthesis and characterization of nanocomposites in which traditional alkoxides are replace by APS. Primary amine groups incorporated into the inorganic network and present on the material surface are determined by reaction with specific chromophores.El uso de 3-aminopropiltrietoxi silano (APS) como precursor inorgánico en la síntesis de materiales híbridos, en sustitución de otros alcóxidos tradicionales como el tetraetilortosilicato (TEOS), abre la posibilidad de incorporar grupos amino reactivos en la red tridimensional. Estos grupos pueden ser utilizados para anclar diferentes compuestos orgánicos al material. Por otro lado, la rápida velocidad de hidrólisis del APS, así como su autocatálisis permite trabajar en condiciones de síntesis muy suaves, tales como medios no ácidos y temperatura ambiente, evitando así la descomposición de los compuestos orgánicos activos. El objetivo de este trabajo es la síntesis y caracterización de nanocomposites en los que los alcóxidos tradicionales han sido sustituidos por APS. Los grupos amino primarios incorporados a la red inorgánica y presentes en la superficie del material se determinan mediante reacciones con cromóforos específicos.

PtPd and Li–PtPd catalysts were prepared by incipient wetness impregnation of the sol–gel prepared mixed γ-Zr phosphate–SiO2 carrier. The catalytic behavior of the Li-modified and its Li-free PtPd/ZPS systems was compared in the simultaneous hydrogenation (HYD) of toluene and naphthalene (NP) in the presence of dibenzothiophene (DBT). Irrespective of the reacting molecule, the Li-modified sample showed higher activity at zero time than its Li-free counterpart. The binding energies of Pt4f7/2 and Pd3d5/2 levels for the Li–PtPd sample were lower than for the PtPd counterpart. This observation suggests that the enhancement in activity at short times on-stream of the Li–PtPd catalyst might be due to the interaction of Li with the support surface that then weakens the metal–support interaction. At times on-stream operation longer than 1 h, the H2S produced in the hydrodesulfurization of dibenzothiophene tends to eliminate the beneficial effect of Li. [Copyright &y& Elsevier]

The study and the characterisation of modern and contemporary oil paintings is still a challenging issue, in particular considering the significant changes in paint production across the 19th and 20th centuries. This paper presents the results of the first physico-chemical integrated study of the artistic materials used in six paintings from the School of Art and Higher Design of Valencia (Escola d'Art i Superior de Disseny, EASD-Valencia), artworks created between 1871 and 1943 by four famous Valencian artists: Salustiano Asenso Arozarena, Salvador Abril I Blasco, Enrique Navas Escuriet and José Bellver Delmás. A wide range of inorganic and organic compounds was identified through a multi-analytical approach by means of visible reflectance spectroscopy, XRF, μ-Raman, FTIR and GC-MS. The investigation on the binding media suggests the use of commercial paint formulations including mixtures of drying, slow- and non-drying oils and the presence of Gum Arabic as well. Traditional pigments (such as vermillion, earth pigments, lead white) and modern pigments (such as zinc white, cobalt and chromium-based pigments) were identified together with fillers and extenders. Degradation products, in particular zinc and lead soaps having strong conservation implications, were also detected. This work, focusing on the identification of the palettes and the binding media used by the selected artists, aims at providing meaningful data and interesting case studies that are useful beyond the Valencian painters solely. This study provides new insight into the use of 19th-20th century commercial oil paints and the selection of painters' palette and their artistic production techniques. Besides, this work highlights the necessity of a multi-analytical approach to obtain valuable information for documentation and preventive conservation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The Iberian Mediterranean Basin is home to one of the largest groups of prehistoric rock art sites in Europe. Despite the cultural relevance of prehistoric Spanish Levantine rock art, pigment composition remains partially unknown, and the nature of the binders used for painting has yet to be disclosed. In this work, we present the first omic analysis applied to one of the flagship Levantine rock art sites: the Valltorta ravine (Castellón, Spain). We used high-throughput sequencing to provide the first description of the bacterial communities colonizing the rock art patina, which proved to be dominated by Firmicutes species and might have a protective effect on the paintings. Proteomic analysis was also performed on rock art microsamples in order to determine the organic binders present in Levantine prehistoric rock art pigments. This information could shed light on the controversial dating of this UNESCO Cultural Heritage, and contribute to defining the chrono-cultural framework of the societies responsible for these paintings.

We present a new multi-analytical approach to the characterization of black pigments in Spanish Levantine rock art. This new protocol seeks to identify the raw materials that were used, as well as reconstruct the different technical gestures and decision-making processes involved in the obtaining of these black pigments. For the first of these goals, the pictorial matter of the black figurative motifs documented at the Les Dogues rock art shelter (Ares del Maestre, Castellón, Spain) was characterized through the combination of physicochemical and archeobotanical analyses. During the first stage of our research protocol, in situ and non-destructive analyses were carried out by means of portable Energy Dispersive X-Ray Fluorescence spectrometry (EDXRF); during the second stage, samples were analyzed by Optical Microscopy (OM), Raman spectroscopy, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM-EDX). Two major conclusions have been drawn from these analyses: first, charred plant matter has been identified as a main component of these prehistoric black pigments; and second, angiosperm and conifer charcoal was a primary raw material for pigment production, identified by means of the archaeobotanical study of plant cells. For the second goal, black charcoal pigments were replicated in the laboratory by using different raw materials and binders and by reproducing two main chaînes opératoires. The comparative study of the structure and preservation of plant tissues of both prehistoric and experimental pigments by means of SEM-EDX underlines both a complex preparation process and the use of likely pigment recipes, mixing raw material with fatty or oily binders. Finally, the formal and stylistic analysis of the motifs portrayed at Les Dogues allowed us to explore the relationship between identified stylistic phases and black charcoal pigment use, raising new archaeological questions concerning the acquisition of know-how and the transfer of traditionally learned chaînes opératoires in Spanish Levantine rock art.

In this work we analyze the pigments used in the decoration of red and yellow motifs present in the portable art of the Parpalló Cave (Gandía, Spain), one of the most important Palaeolithic sites in the Spanish Mediterranean region. Energy dispersive X-ray fluorescence spectrometry (EDXRF) and spectrophotometry in the visible region (CIEL*a*b*color coordinates and spectral reflectance curves) were used to perform in situ fast analyses of the red and yellow motifs with portable equipment and to characterize their elemental composition and their colorimetric perception, respectively. According to the elemental composition, the intensity of the fluorescence iron signals in red and yellow motifs are higher than average values in the rock substrates. As expected, red motifs possess high values of the chromatic coordinate a* and yellow motifs possess high values of b*. This characterization was complemented with FT-IR analyses of microsamples detached from the red and yellow colored zones of a small set of plaquettes. Our results show that the artists used red and yellow pigments in the decoration likely derived from natural iron oxides as hematite and goethite., Competing Interests: The authors have declared that no competing interests exist.

Nanoparticulate bimodal porous silica-based materials have been prepared through a surfactant-assisted procedure by using a simple template and starting from inexpensive sodium silicate as silicon source. Different procedural variables, such as pH or the nature and concentration of the surfactant, have been explored to optimize the preparative protocol, which allows, in turn, improved understanding of the formation process. The final bulk materials (called UVM-10 or M-UVM-10) are formed by pseudomorphic transformation of fresh silica-based xerogels under mild basic conditions. The UVM-10 architecture is constructed from small mesoporous nanoparticles, the aggregation of which generates a disordered secondary 3 D pore system (large-meso/macropores) defined by interparticle voids. Modulation of the intraparticle mesopore size is achieved by using surfactants with variable tail lengths, while maintaining the same head group. Textural porosity has been handled independently by hydrothermally modifying the particle size of the reactive silica-based xerogel. By simply adding metal alkoxides to the initial reaction mixture, the preparative protocol allows for functionalizing the silica walls by incorporating relatively high proportions of homogeneously dispersed heteroelements, such as Al and Ti., (Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The elemental distribution of self-organized In-rich In(x)Ga1-xN nanowires grown by plasma-assisted molecular beam epitaxy has been investigated using three different techniques with spatial resolution on the nanoscale. Two-dimensional images and elemental profiles of single nanowires obtained by x-ray fluorescence and energy-dispersive x-ray spectroscopy, respectively, have revealed a radial gradient in the alloy composition of each individual nanowire. The spectral selectivity of resonant Raman scattering has been used to enhance the signal from very small volumes with different elemental composition within single nanowires. The combination of the three techniques has provided sufficient sensitivity and spatial resolution to prove the spontaneous formation of a core–shell nanowire and to quantify the thicknesses and alloy compositions of the core and shell regions. A theoretical model based on continuum elastic theory has been used to estimate the strain fields present in such inhomogeneous nanowires. These results suggest new strategies for achieving high quality nonpolar heterostructures.

Two sites of the Neandertal-associated Middle Paleolithic of Iberia, dated to as early as approximately 50,000 years ago, yielded perforated and pigment-stained marine shells. At Cueva de los Aviones, three umbo-perforated valves of Acanthocardia and Glycymeris were found alongside lumps of yellow and red colorants, and residues preserved inside a Spondylus shell consist of a red lepidocrocite base mixed with ground, dark red-to-black fragments of hematite and pyrite. A perforated Pecten shell, painted on its external, white side with an orange mix of goethite and hematite, was abandoned after breakage at Cueva Antón, 60 km inland. Comparable early modern human-associated material from Africa and the Near East is widely accepted as evidence for body ornamentation, implying behavioral modernity. The Iberian finds show that European Neandertals were no different from coeval Africans in this regard, countering genetic/cognitive explanations for the emergence of symbolism and strengthening demographic/social ones.

The topotactic reaction of gamma-ZrPO(4)[O(2)P(OH)(2)].2H(2)O (gamma-ZrP) with benzenediphosphonic acid was examined in water and in acetone-water mixtures. This reaction was found to take place in water only on the external surface of the microcrystals, and pillared compounds were never obtained, even after very long reaction times. On the contrary, covalently pillared compounds were quickly obtained in acetone-water mixtures. The mechanism of the latter topotactic reaction was investigated by determining the rate of the phosphate groups released and the rate of the benzenediphosphonates taken up by gamma-ZrP over a long time (50 days). These data showed that pillared derivatives of gamma-ZrP can be obtained because colloidal dispersions of exfoliated lamellae are formed in acetone-water mixtures. The diphosphonate group acts initially as a monovalent species, replacing only one dihydrogen phosphate group on the surface of the exfoliated gamma-lamellae. The colloidal and partially derivatized lamellae thus formed can interact with each other by forming polylamellar pillared systems. When the number of pillared lamellae exceeds a given value (usually 5-6), flocculation of the colloidal gamma-ZrP takes place. Topotactic reactions between packets of pillared lamellae may also continue in the flocculated system. Therefore, the average number of the pillared lamellae slowly increases over time.

The rates of the topotactic reactions between gamma-zirconium phosphate and phenylphosphonic acid in water and water-acetone mixtures at various temperatures were investigated. The slow rates of the process in aqueous medium or in water-acetone mixtures at temperatures lower than 50 degrees C were attributed to a slow interdiffusion of O(2)P(OH)(2)(-) and O(2)P(OH)(C(6)H(5))(-) groups in the interlayer region of gamma-ZrP. Similar to ion-exchange processes, the replacement begins in the external part of the interlayer region and progresses toward the central region with the formation of an advancing phase boundary. In water-acetone mixtures at temperatures higher than 60 degrees C an exfoliation of gamma-ZrP was found. Thus, the initial process is very fast since the substitution can take place directly on the surface of the exfoliated gamma-lamellae. However, after a certain degree of substitution, a flocculation of the colloidal dispersion, which slows down the rate of the further topotactic substitution, was observed. Some considerations on the topotactic substitution occurring on the surface of the exfoliated lamellae and on the mechanism of the diffusion of the exchanging species in the interlayer region are also reported.