Petrography and mineral chemistry of carbonatites and mica-rich rocks from the Araxá complex (Alto Paranaíba Province, Brazil)

The Araxá complex (16 km²) comprises carbonatites forming a central core and a complex network of concentric and radial dykes as well as small veins; additionally, it includes mica-rich rocks, phoscorites and lamprophyres. Fenites also occur and are represented by Proterozoic quartzites and schists of the Araxá Group. The petrographic study of 130 borehole samples indicates that the complex is basically made up by two rock-types, carbonatites and mica-rich rocks, and subordinately by a third unit of hybrid composition. Carbonatites range chemically in composition, the most abundant type being magnesiocarbonatites. Dolomite and calcite correspond to the chief constituents, but other carbonate phases, including the Ce-group RE minerals, are also recognized. Phosphates and oxides are widespread accessories whereas silicate minerals consist of olivine, clinopyroxene, mica and amphibole. Mica-rich rocks are represented by abundant glimmeritic rocks and scarce cumulitic phlogopite-, olivine- and diopside-bearing pyroxenites. Hybrid rocks mainly contain phlogopite and tetraferriphlogopite as cumulus and intercumulus phases, respectively; carbonate minerals may also be found. Chemical data indicate that the carbonatites are strongly enriched in REE and have lower contents of Nb, Zr, V, Cr, Ni and Rb compared to the mica-rich rocks. The higher K, Nb and Zr contents of the latter rocks are believed to be related to metasomatic processes (glimmeritization) of the pyroxenites. Similar REE patterns for carbonatites and mica-rich rocks seem to suggest that they are related to a single parental magma, possibly of ijolitic composition. Steep LREE/HREE fractionation and high sigmaREE content of some carbonatite samples would be explained by hydrothermal and supergenic processes

Pesaro. Il piano particolareggiato e le architetture del piano. Video, soggetto di Riccarda Cantarelli, a cura di Serena Maffioletti. Video prodotto da Archivio Progetti Iuav

L’Archivio Progetti Iuav, in occasione del decennale della morte di Carlo Aymonino, ha dato un incarico di studio a Riccarda Cantarelli per indagare sul “Piano particolareggiato del Centro Storico di Pesaro”: un’opera collettiva, espressione dell’unità architettura-urbanistica, che costituisce il manifesto più completo e maturo della ricerca e dell’attuazione delle teorie del Gruppo Architettura dell’IUAV. Il video documentale è parte di questa ricerca

Petrography and mineral chemistry of carbonatites and mica-rich rocks from the Araxá complex (Alto Paranaíba Province, Brazil)

The Araxá complex (16 km²) comprises carbonatites forming a central core and a complex network of concentric and radial dykes as well as small veins; additionally, it includes mica-rich rocks, phoscorites and lamprophyres. Fenites also occur and are represented by Proterozoic quartzites and schists of the Araxá Group. The petrographic study of 130 borehole samples indicates that the complex is basically made up by two rock-types, carbonatites and mica-rich rocks, and subordinately by a third unit of hybrid composition. Carbonatites range chemically in composition, the most abundant type being magnesiocarbonatites. Dolomite and calcite correspond to the chief constituents, but other carbonate phases, including the Ce-group RE minerals, are also recognized. Phosphates and oxides are widespread accessories whereas silicate minerals consist of olivine, clinopyroxene, mica and amphibole. Mica-rich rocks are represented by abundant glimmeritic rocks and scarce cumulitic phlogopite-, olivine- and diopside-bearing pyroxenites. Hybrid rocks mainly contain phlogopite and tetraferriphlogopite as cumulus and intercumulus phases, respectively; carbonate minerals may also be found. Chemical data indicate that the carbonatites are strongly enriched in REE and have lower contents of Nb, Zr, V, Cr, Ni and Rb compared to the mica-rich rocks. The higher K, Nb and Zr contents of the latter rocks are believed to be related to metasomatic processes (glimmeritization) of the pyroxenites. Similar REE patterns for carbonatites and mica-rich rocks seem to suggest that they are related to a single parental magma, possibly of ijolitic composition. Steep LREE/HREE fractionation and high sigmaREE content of some carbonatite samples would be explained by hydrothermal and supergenic processes

Analytical characterization of Pd/ZrO2 composite nanoparticles employed in heterogeneous catalysis

Pd/ZrO2 nanocomposite materials were synthesised following a two-step procedure. Firstly, tetragonal zirconia was prepared via a chemical route; then it was subjected to an in-situ electrochemical impregnation with palladium nanoparticles. Different process times lead to a different Pd loading in the resulting material. Pd/ZrO2, powders were subjected to morphological and spectroscopic characterisation. Transmission electron microscopy (TEM) analysis showed that ZrO2 nanograins have an average size of 150±70nm, and are composed of smaller sub-grains (average diameter = 40±10 nm). Spherical Pd nanoparticles are evenly dispersed on the oxide support, their average core diameter being 6.9±1.8 nm. X-ray Photoelectron Spectroscopy (XPS) was used to asses the materials surface chemical composition. Testing the catalysts for the CO oxidation revealed an appreciable activity of the Pd-modified ZrO2 samples. TEM and XPS analyses were also performed on materials exposed to prolonged catalytic runs and contributed to shed light on the catalysis mechanism. A rationale for the results obtained on the CO conversion process was proposed, invoking a key- catalytic role of finely dispersed PdO sites. The nanomaterial morphological stability and reactivity encouraged to employ it in the Heck synthesis of butyl cinnamate. This process was demonstrated to take place with high conversion values and interesting stability towards catalyst recycling

Insights in the etiopathology of galactosyltransferase II (GalT-II) deficiency from transcriptome-wide expression profiling of skin fibroblasts of two sisters with compound heterozygosity for two novel B3GALT6 mutations

Mutations in B3GALT6, encoding the galactosyltransferase II (GalT-II) involved in the synthesis of the glycosaminoglycan (GAG) linkage region of proteoglycans (PGs), have recently been associated with a spectrum of connective tissue disorders, including spondyloepimetaphyseal dysplasia with joint laxity type 1 (SEMDJL1) and Ehlers–Danlos-like syndrome. Here, we report on two sisters compound heterozygous for two novel B3GALT6 mutations that presented with severe short stature and progressive kyphoscoliosis, joint hypermobility and laxity, hyperextensible skin, platyspondyly, short ilia, and elbow malalignment. Microarray-based transcriptome analysis revealed the differential expression of several genes encoding extracellular matrix (ECM) structural components, including COMP, SPP1, COL5A1, and COL15A1, enzymes involved in GAG synthesis and in ECM remodeling, such as CSGALNACT1, CHPF, LOXL3, and STEAP4, signaling transduction molecules of the TGFβ/BMP pathway, i.e., GDF6, GDF15, and BMPER, and transcription factors of the HOX and LIM families implicated in skeletal and limb development. Immunofluorescence analyses confirmed the down-regulated expression of some of these genes, in particular of the cartilage oligomeric matrix protein and osteopontin, encoded by COMP and SPP1, respectively, and showed the predominant reduction and disassembly of the heparan sulfate specific GAGs, as well as of the PG perlecan and type III and V collagens. The key role of GalT-II in GAG synthesis and the crucial biological functions of PGs are consistent with the perturbation of many physiological functions that are critical for the correct architecture and homeostasis of various connective tissues, including skin, bone, cartilage, tendons, and ligaments, and generates the wide phenotypic spectrum of GalT-II-deficient patients

Copper nanoparticles/polymer composites with antifungal and bacteriostatic properties

A spinnable coating capable of releasing metal species to a broth of living organisms in a controlled manner is an extremely interesting material for a number of biotechnological applications. Polymer/ metal nanocomposites are a viable choice but very little is known about their biological properties. Here, a polymer based nanocomposite loading stabilized copper nanoparticles is proposed as a biostatic coating and systematic correlations between material properties and biological effects are established. Experimental proof of the nanocomposite capability to release metal species in a controlled manner and eventually to slow or even inhibit the growth of living organisms, such as fungi and other pathogenic microorganisms, are provided. The biostatic activity is correlated to the nanoparticle loading that controls the release of copper species, independently evaluated by means of electro-thermal atomic absorption spectroscopy. Insights into the understanding of the controlled releasing process, involving CuO dissolution through the nanoclusters stabilizing layer, are also proposed