Patent foramen ovale (PFO) is a flaplike opening in the fossa ovalis; between the septum primum and secundum. It is highly prevalent with approximately 25% of the population having a PFO. It is ...usually asymptomatic but can rarely cause paradoxical embolism leading to stroke and/or significant right to left shunting causing hypoxia. The complications of PFO closure with a percutaneous device include embolization, cardiac perforation, and thrombosis. These are all early complications. We describe the case of a patient with a history of PFO closure who had device thrombosis 3 years after implantation. Management includes anticoagulation with warfarin. Repeat cardiac imaging to document the resolution of thrombosis is recommended.
Nickel hypersensitivity is a rarely reported complication of percutaneous patent foramen ovale/atrial septal defect closure. Herein, we report a case of systemic allergic contact dermatitis to nickel ...present in a GORE CARDIOFORM (W.L. Gore, Flagstaff, Arizona) septal occluder that resolved following explanation. To our knowledge this is the first published case of nickel hypersensitivity associated with this device. (
Level of Difficulty: Beginner.
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Most of the World's germanium (Ge) is mined from Ge-rich lignite, where it is commonly associated with elevated arsenic (As), tungsten (W) and beryllium (Be) contents. Over the past decade, new ...evidence showing that World-class Ge deposits result from the interaction of hydrothermal fluids with organic matter in coal seams has emerged. Yet, the chemical state of Ge and associated metals in lignite remains poorly understood. We used Mega-pixel Synchrotron X-ray Fluorescence (MSXRF), X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) to characterize the oxidation states and chemical bonding environment of Ge, As, and W in two world-class Mesozoic Ge-in-lignite deposits (Lincang, Yunnan, southwestern China; Wulantuga, Inner Mongolia, northeastern China); in lignite-bearing uranium (U) ores from the Beverley deposit (South Australia) hosted in Eocene sandstones; and in lignite and preserved wood in late Oligocene-Miocene fluviatile sediments (Gore, Southland, New Zealand). The aim was to improve our understanding of the enrichment mechanism of Ge in lignite and better evaluate the environmental mobility of Ge and some of the associated metals (specifically As and W) in lignite ores.
In all samples, chemical maps show that Ge is distributed homogeneously (down to 2μm) within the organic matter. XANES and EXAFS data show that Ge exists in the tetravalent oxidation state and in a distorted octahedral coordination with O, consistent with complexing of Ge by organic ligands. In some pyrite-bearing samples, a minor fraction of Ge is also present as Ge(IV) in association with pyrite. In contrast, As displays a more complex speciation pattern, sometimes even in a single sample, including As(III), As(V), and As(−I/+II) in solid solution in sulfides. Arsenic in sulfides occurs in anionic and cationic forms, i.e., it shows both the common substitution for S22− and the substitution for Fe recently discovered in some hydrothermal pyrites. Tungsten was present as W(VI) in distorted octahedral (3+3) coordination. The EXAFS data confirm the absence or minor contribution of individual W-rich minerals such as scheelite or ferberite to W mass balance in the studied samples.
These data show that Ge, W, and probably some As are scavenged via formation of insoluble, oxygen-bridged metal organic complexes in lignite. Destruction of the organic ligands responsible for fixing Ge and W (As) in these lignites is required for liberating the metals, e.g. from waste materials. Geochemical modelling suggests that Ge, W, Be and As all can be extracted from granitic rocks by dilute, low temperature hydrothermal fluids. Germanium is transported mainly as the tetrahedral Ge(OH)4(aq) complex, but fixed as an octahedral oxy-bridged organic complex. The same situation is valid for W, which is transported at the tetrahedral tungstate ion, but most likely scavenged via formation of a 6-coordinated metal-organic species. The Ge-Be-W±As association in Ge-rich coals reflects the source of the metals as well as related scavenging mechanisms.
•The garnet megacrysts of Gore Mountain contain former melt inclusions.•Quartz and feldspar polymorphs commonly found as crystallization products of the trapped melt.•Melt production at ultrahigh ...temperature conditions (≥940°C) as result of H2O-present melting of a lower crustal gabbro.•First instance of TTG embryos found in their mafic source rock.•Their mismatched signature suggests that trace elements may not be diagnostic of depth of melting and geodynamic setting.
The garnet megacrysts of Gore Mountain (Adirondacks, US) are world-renown crystals due to their size, up to 1 m in historical record, which makes them the largest known garnets on the planet. We show here that they are also host to the first primary inclusions of trondhjemitic melt found in natural mafic rocks. The petrological and experimental investigation of the inclusions, coupled with phase equilibrium modelling, shows that this melt is the result of H2O-fluxed partial melting at T>900°C of a lower crustal gabbro. The compositional similarity between the trondhjemitic melt inclusions and tonalitic–trondhjemitic–granodioritic (TTGs) melts makes these inclusions a direct natural evidence that melting of mafic rocks generates TTG-like melts, and provides us with the possibility to clarify processes responsible for the formation of the early continental crust. These TTG embryos represent the trondhjemitic end-member of the melts whose emplacement at upper crustal levels, after being modified by mixing and crystallization-related processes, leads to the formation of the TTG terranes. Moreover, our study shows how the melt from H2O-fluxed melting of mafic lower crust has mismatched major and trace element signatures, previously interpreted as evidence of melting at very different pressures. This poses serious limitations to the established use of some chemical features to identify the geodynamic settings (e.g. subduction versus thickened crust) responsible for TTGs generation and the growth of early crust.
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This work describes the development of a disposable and wearable screen-printed electrochemical sensor for the determination of chloride ions. The sensor includes three screen-printed ...electrodes: a working, an auxiliary (both carbon paste electrodes), and an Ag/AgCl pseudo-reference electrode. The sensor works by measuring the Nernstian shift of the voltammetric peak potential of ferrocenemethanol in the presence of chloride ions, due to the use of a pseudo-reference electrode in the electrodic system. The measurements are easily taken by dropping the sample onto the electrodic surface.
Different flexible materials, including textiles, were studied as substrates of the electrodic system. A study of ink adherence and conductivity in these materials was carried out. The use of Gore-Tex® displayed good ink adherence, acceptable conductivity and waterproof properties. These features make it an excellent support for wearable sensors.
The reproducibility and repeatability, in terms of relative standard deviation values of the developed Gore-Tex sensor, were below 3% (n=5) and the detection limit was 0.2mM (α=β=0.05).
The sensor was successfully applied to determine the chloride content in sea water.
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