Mechanisms for Pd-Au enrichment in porphyry-epithermal ores of the Elatsite deposit, Bulgaria.

Porphyry Cu can contain significant concentrations of platinum-group elements (PGE: Os, Ir, Ru, Rh, Pt, Pd). In this study, we provide a comprehensive in situ analysis of noble metals (PGE, Au, Ag) for (Cu-Fe)-rich sulfides from the Elatsite, one of the world's PGE-richest porphyry Cu deposits. These data, acquired using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), indicate that Pd was concentrated in all the (Cu-Fe)-rich sulfides at ppm-levels, with higher values in pyrite (~6 ppm) formed at the latest epithermal stage (i.e., quartz-galena-sphalerite assemblage) than in bornite and chalcopyrite (<5 ppm) from the hypogene quartz-magnetite-bornite-chalcopyrite ores. Likewise, Au is significantly more concentrated in pyrite (~5 ppm) than in the (Cu-Fe)-rich sulfides (≤0.08 ppm). In contrast, Ag reaches hundreds of ppm in pyrite and bornite (~240 ppm) but is in much lesser amounts in chalcopyrite (<25 ppm). The inspection of the time-resolved spectra collected during LA-IPC-MS analyses indicates that noble metals are present in the sulfides in two forms: (1) structurally bound (i.e., solid solution) in the lattice of sulfides and, (2) as nano- to micron-sized inclusions (Pd-Te and Au). These observations are further confirmed by careful investigations of the PGE-rich (Cu-Fe)-rich sulfides by combining high-spatial resolution of field emission scanning electron microscope (FESEM) and focused ion beam and high-resolution transmission electron microscopy (FIB/HRTEM). A typical Pd-bearing mineral includes the composition PdTe2 close to the ideal merenskyite but with a distinct crystallographic structure, whereas Au is mainly found as native element. Our detailed mineralogical study coupled with previous knowledge on noble-metal inclusions in the studied ores reveals that noble metal enrichment in the Elatsite porphyry ores was mainly precipitated from droplets of Au-Pd-Ag telluride melt (s) entrained in the high-temperature hydrothermal fluid. These telluride melts could separate at the time of fluid unmixing from the silicate magma or already be present in the latter either derived from deep-seated crustal or mantle sources. Significant enrichment in Pd and Au (the latter correlated with As) in low-temperature pyrite is interpreted as remobilization of these noble metals from pre-existing hypogene ores during the epithermal overprinting.

Importancia del dióxido de carbono en el paciente crítico: implicaciones a nivel celular y clínico / Importance of carbon dioxide in the critical patient: Implications at the cellular and clinical levels

En los últimos años han surgido importantes descubrimientos sobre el papel del dióxido de carbono (CO2) a nivel celular y molecular, y sobre los efectos de la hipercapnia. Esta última puede tener efectos beneficiosos en pacientes con patología pulmonar aguda, como la reducción de la inflamación pulmonar y del daño oxidativo alveolar, la regulación de la inmunidad innata, la defensa del huésped y la inhibición de la expresión de citoquinas inflamatorias. Sin embargo, otros estudios sugieren que el CO2 puede tener efectos nocivos en el pulmón, como retraso en la reparación alveolar tras la injuria pulmonar, disminución de las tasas de reabsorción del fluido alveolar e inhibición de la proliferación de células alveolares. Por lo tanto, la hipercapnia tiene efectos tanto beneficiosos como nocivos y es importante determinar el efecto neto en condiciones específicas. El propósito de esta revisión es describir los efectos fisiológicos e inmunomoduladores de la hipercapnia, considerando sus potenciales consecuencias en el paciente con insuficiencia respiratoria aguda

Important recent insights have emerged regarding the cellular and molecular role of carbon dioxide (CO2) and the effects of hypercapnia. The latter may have beneficial effects in patients with acute lung injury, affording reductions in pulmonary inflammation, lessened oxidative alveolar damage, and the regulation of innate immunity and host defenses by inhibiting the expression of inflammatory cytokines. However, other studies suggest that CO2 can have deleterious effects upon the lung, reducing alveolar wound repair in lung injury, decreasing the rate of reabsorption of alveolar fluid, and inhibiting alveolar cell proliferation. Clearly, hypercapnia has both beneficial and harmful consequences, and it is important to determine the net effect under specific conditions. The purpose of this review is to describe the immunological and physiological effects of carbon dioxide, considering their potential consequences in patients with acute respiratory failure

Importance of carbon dioxide in the critical patient: Implications at the cellular and clinical levels. / Importancia del dióxido de carbono en el paciente crítico: implicaciones a nivel celular y clínico.

Important recent insights have emerged regarding the cellular and molecular role of carbon dioxide (CO2) and the effects of hypercapnia. The latter may have beneficial effects in patients with acute lung injury, affording reductions in pulmonary inflammation, lessened oxidative alveolar damage, and the regulation of innate immunity and host defenses by inhibiting the expression of inflammatory cytokines. However, other studies suggest that CO2 can have deleterious effects upon the lung, reducing alveolar wound repair in lung injury, decreasing the rate of reabsorption of alveolar fluid, and inhibiting alveolar cell proliferation. Clearly, hypercapnia has both beneficial and harmful consequences, and it is important to determine the net effect under specific conditions. The purpose of this review is to describe the immunological and physiological effects of carbon dioxide, considering their potential consequences in patients with acute respiratory failure.

Mass Spectrometric and Synchrotron Radiation based techniques for the identification and distribution of painting materials in samples from paints of Josep Maria Sert.

BACKGROUND: Establishing the distribution of materials in paintings and that of their degradation products by imaging techniques is fundamental to understand the painting technique and can improve our knowledge on the conservation status of the painting. The combined use of chromatographic-mass spectrometric techniques, such as GC/MS or Py/GC/MS, and the chemical mapping of functional groups by imaging SR FTIR in transmission mode on thin sections and SR XRD line scans will be presented as a suitable approach to have a detailed characterisation of the materials in a paint sample, assuring their localisation in the sample build-up. This analytical approach has been used to study samples from Catalan paintings by Josep Maria Sert y Badía (20th century), a muralist achieving international recognition whose canvases adorned international buildings. RESULTS: The pigments used by the painter as well as the organic materials used as binders and varnishes could be identified by means of conventional techniques. The distribution of these materials by means of Synchrotron Radiation based techniques allowed to establish the mixtures used by the painter depending on the purpose. CONCLUSIONS: Results show the suitability of the combined use of SR µFTIR and SR µXRD mapping and conventional techniques to unequivocally identify all the materials present in the sample and their localization in the sample build-up. This kind of approach becomes indispensable to solve the challenge of micro heterogeneous samples. The complementary interpretation of the data obtained with all the different techniques allowed the characterization of both organic and inorganic materials in the samples layer by layer as well as to establish the painting techniques used by Sert in the works-of-art under study.