108 research outputs found
Relationship between membrane sterol composition and responsiveness to 12-O-tetradecanoylphorbol 13-acetate in HL-60 human promyelocytic leukaemia cell lines
Subduction metamorphism of serpentiniteâhosted carbonates beyond antigorite-serpentinite dehydration (NevadoâFilĂĄbride Complex, Spain)
I. MartĂnez Segura and M. J. RomĂĄn Alpiste are thanked for their kind assistance during sample preparation and SEM operation, and M. T. GĂłmezâPugnaire and A. Jabaloy for early work on Almirez ophicarbonates. We are grateful to the Sierra Nevada National Park for providing permits for fieldwork and sampling at the Almirez massif. We further acknowledge the editorial handling by D. Whitney and D. Robinson and the reviews of M. Galvez and T. Pettke, whose comments and constructive criticism helped to improve the manuscript.
We acknowledge funding from the European Union FP7 MarieâCurie Initial Training Network ABYSS under REA Grant Agreement no. 608001 in the framework of M.D.M.'s PhD project, the Spanish âAgencia Estatal de InvestigaciĂłnâ (AEI) grants no. CGL2016â75224âR to V.L.S.âV and CGL2016â81085âR to C.J.G and C.M and grant no. PCINâ2015â053 to C.J.G. The âJunta de AndalucĂaâ is also thanked for funding under grants no. RNMâ131, RNMâ374 and P12âRNMâ3141. C.M. thanks MINECO for financing a RamĂłn y Cajal fellowship no. RYCâ2012â11314 and K.H. for a Juan de la Cierva Fellowship no. FPDIâ2013â16253 and a research contract under grant no. CGL2016â81085âR. This work and the research infrastructure at the IACT have received (co)funding from the European Social Fund and the European Regional Development Fund.At subâarc depths, the release of carbon from subducting slab lithologies is mostly
controlled by fluid released by devolatilization reactions such as dehydration of antigorite (Atgâ) serpentinite to prograde peridotite. Here we investigate carbonateâsilicate rocks hosted in Atgâserpentinite and prograde chlorite (Chlâ) harzburgite in the
Milagrosa and Almirez ultramafic massifs of the palaeoâsubducted NevadoâFilĂĄbride
Complex (NFC, Betic Cordillera, S. Spain). These massifs provide a unique opportunity to study the stability of carbonate during subduction metamorphism at PâT
conditions before and after the dehydration of Atgâserpentinite in a warm subduction
setting. In the Milagrosa massif, carbonateâsilicate rocks occur as lenses of Tiâclinohumiteâdiopsideâcalcite marbles, diopsideâdolomite marbles and antigoriteâdiopsideâdolomite rocks hosted in clinopyroxeneâbearing Atgâserpentinite. In Almirez,
carbonateâsilicate rocks are hosted in Chlâharzburgite and show a highâgrade assemblage composed of olivine, Tiâclinohumite, diopside, chlorite, dolomite, calcite, Crâ
bearing magnetite, pentlandite and rare aragonite inclusions. These NFC
carbonateâsilicate rocks have variable CaO and CO2 contents at nearly constant Mg/
Si ratio and high Ni and Cr contents, indicating that their protoliths were variable
mixtures of serpentine and Caâcarbonate (i.e., ophicarbonates). Thermodynamic
modelling shows that the carbonateâsilicate rocks attained peak metamorphic conditions similar to those of their host serpentinite (Milagrosa massif; 550â600°C and
1.0â1.4 GPa) and Chlâharzburgite (Almirez massif; 1.7â1.9 GPa and 680°C).
Microstructures, mineral chemistry and phase relations indicate that the hybrid carbonateâsilicate bulk rock compositions formed before prograde metamorphism,
likely during seawater hydrothermal alteration, and subsequently underwent subduction metamorphism. In the CaOâMgOâSiO2 ternary, these processes resulted in a
compositional variability of NFC serpentiniteâhosted carbonateâsilicate rocks along
the serpentineâcalcite mixing trend, similar to that observed in serpentiniteâhosted
carbonateârocks in other palaeoâsubducted metamorphic terranes. Thermodynamic modelling using classical models of binary H2OâCO2 fluids shows that the compositional variability along this binary determines the temperature of the main devolatilization reactions, the fluid composition and the mineral assemblages of reaction
products during prograde subduction metamorphism. Thermodynamic modelling
considering electrolytic fluids reveals that H2O and molecular CO2 are the main fluid
species and charged carbonâbearing species occur only in minor amounts in equilibrium with carbonateâsilicate rocks in warm subduction settings. Consequently, accounting for electrolytic fluids at these conditions slightly increases the solubility of
carbon in the fluids compared with predictions by classical binary H2OâCO2 fluids,
but does not affect the topology of phase relations in serpentiniteâhosted carbonateâ
rocks. Phase relations, mineral composition and assemblages of Milagrosa and
Almirez (meta)âserpentiniteâhosted carbonateâsilicate rocks are consistent with local
equilibrium between an infiltrating fluid and the bulk rock composition and indicate
a limited role of infiltrationâdriven decarbonation. Our study shows natural evidence
for the preservation of carbonates in serpentiniteâhosted carbonateâsilicate rocks beyond the Atgâserpentinite breakdown at subâarc depths, demonstrating that carbon
can be recycled into the deep mantle.Funding from the European Union FP7 MarieâCurie Initial Training Network ABYSS under REA Grant Agreement no. 608001Spanish âAgencia Estatal de InvestigaciĂłnâ (AEI) grants no. CGL2016â75224âR to V.L.S.âV and CGL2016â81085âR to C.J.G and C.M and grant no. PCINâ2015â053 to C.J.GJunta de AndalucĂa Funding under grants no. RNMâ131, RNMâ374 and P12âRNMâ3141MINECO for financing a RamĂłn y Cajal fellowship no. RYCâ2012â11314 and K.H. for a Juan de la Cierva Fellowship no. FPDIâ2013â16253 and a research contract under grant no. CGL2016â81085â
The impact of antiretroviral therapy on iron homeostasis and inflammation markers in HIV-infected patients with mild anemia
Magmatism, serpentinization and life: Insights through drilling the Atlantis Massif (IODP Expedition 357)
IODP Expedition 357 used two seabed drills to core 17 shallow holes at 9 sites across Atlantis Massif ocean core complex (Mid-Atlantic Ridge 30°N). The goals of this expedition were to investigate serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. More than 57 m of core were recovered, with borehole penetration ranging from 1.3 to 16.4 meters below seafloor, and core recovery as high as 75% of total penetration in one borehole. The cores show highly heterogeneous rock types and alteration associated with changes in bulk rock chemistry that reflect multiple phases of magmatism, fluid-rock interaction and mass transfer within the detachment fault zone. Recovered ultramafic rocks are dominated by pervasively serpentinized harzburgite with intervals of serpentinized dunite and minor pyroxenite veins; gabbroic rocks occur as melt impregnations and veins. Dolerite intrusions and basaltic rocks represent the latest magmatic activity. The proportion of mafic rocks is volumetrically less than the amount of mafic rocks recovered previously by drilling the central dome of Atlantis Massif at IODP Site U1309. This suggests a different mode of melt accumulation in the mantle peridotites at the ridge-transform intersection and/or a tectonic transposition of rock types within a complex detachment fault zone. The cores revealed a high degree of serpentinization and metasomatic alteration dominated by talc-amphibole-chlorite overprinting. Metasomatism is most prevalent at contacts between ultramafic and mafic domains (gabbroic and/or doleritic intrusions) and points to channeled fluid flow and silica mobility during exhumation along the detachment fault. The presence of the mafic lenses within the serpentinites and their alteration to mechanically weak talc, serpentine and chlorite may also be critical in the development of the detachment fault zone and may aid in continued unroofing of the upper mantle peridotite/gabbro sequences.
New technologies were also developed for the seabed drills to enable biogeochemical and microbiological characterization of the environment. An in situ sensor package and water sampling system recorded real-time variations in dissolved methane, oxygen, pH, oxidation reduction potential (Eh), and temperature and during drilling and sampled bottom water after drilling. Systematic excursions in these parameters together with elevated hydrogen and methane concentrations in post-drilling fluids provide evidence for active serpentinization at all sites. In addition, chemical tracers were delivered into the drilling fluids for contamination testing, and a borehole plug system was successfully deployed at some sites for future fluid sampling. A major achievement of IODP Expedition 357 was to obtain microbiological samples along a westâeast profile, which will provide a better understanding of how microbial communities evolve as ultramafic and mafic rocks are altered and emplaced on the seafloor. Strict sampling handling protocols allowed for very low limits of microbial cell detection, and our results show that the Atlantis Massif subsurface contains a relatively low density of microbial life
Point sur les appareils domestiques de traitement d'eau
L'installation d'appareils domestiques de traitement d'eau est de plus en plus courante en France, et pour le moment non contrĂŽlĂ©e par les autoritĂ©s sanitaires. Ce travail a eu pour objet d'Ă©tablir un Ă©tat des lieux de la situation en France afĂn d'aider a le prise de decision en la matiĂšre.
Un court recensement des différents appareils de traitement met en avant leurs avantages et inconvénients et fournit des indications sur leur efficacité.
Les quelques Ă©tudes menees Ă ce jour ne permettent pas de conclure Ă l'absence de risques pour la santĂ© des consommateurs. Le risque liĂ© ĂĄ une contamination microbienne semble cependant le plus important, et principalement liĂ© Ă la qualitĂ© de la maintenance. Des Ă©tudes devraient ĂȘtre poursuivies pour Ă©tablir de façon plus precise les risques sanitaires encourus par les utilisateurs de tels dispositifs.
Le marché des appareils de traitement d'eau est un marché éclaté, difficile a appréhender et a contrÎler. Les outils disponibles (réglementation, normalisation et certification) ne garantissent pas, dans leurs modalités d'application actuelles, leur efficacité et leur innocuité.
DiffĂ©rents types de controles peuvent ĂȘtre imagines Ă divers stades de la chame de fabrication et de distribution de ces produits. Pour ce qui concerne les produits neufs, le dĂ©veloppement et la mise en ceuvre d'un essai de controle de l'innocuitĂ© sanitaire des appareils est important.
Un protocole existe, mais il pourrait largement simplifié sans impacter de maniere significative sur sa dimension sanitaire. Les protocoles établis par NSF, DWI et la circulaire du 25 novembre 2002 constituent d'autres bonnes sources d'inspiration.
Quant au contrĂŽle de leur efficacitĂ© il ne semble pas constituer un enjeu sanitaire majeur en France dans la mesure oĂč l'eau est supposĂ©e potable au compteur. Cet aspect ne nĂ©cessite done sans doute pas un cadre rĂ©glementaire.
Avant tout, les efforts devraient étre concentres sur l'installation et la maintenance des systémes domestiques de traitement et sur le professionnalisme des techniciens intervenant sur ces produits
A new radiochemical assay for gamma-glutamyl transpeptidase. Its application to the analysis of the hepatic subcellular distrubition of the enzyme.
Hepatic microsomal metabolism of 1,3-butadiene.
1. In rat liver microsomes, 1,3-butadiene was metabolized to butadiene monoxide, which was subsequently transformed into 3-butene-1,2-diol by microsomal epoxide hydrolase. 2. In the metabolism of butadiene oxide in microsomes, four metabolites were detected, namely two stereoisomers of DL-diepoxybutane, and two stereoisomers of 3,4-epoxy-1,2-butanediol. No meso-diepoxybutane was detected
Characterization of a secreted form of measles virus haemagglutinin expressed from a vaccinia virus recombinant
- âŠ