5,981 research outputs found
cFFR as an alternative to FFR: please do not contrast simplicity!
info:eu-repo/semantics/publishedVersio
The Multi-center Evaluation of the Accuracy of the Contrast MEdium INduced Pd/Pa RaTiO in Predicting FFR (MEMENTO-FFR) Study.
AIMS:
Adenosine administration is needed for the achievement of maximal hyperaemia fractional flow reserve (FFR) assessment. The objective was to test the accuracy of Pd/Pa ratio registered during submaximal hyperaemia induced by non-ionic contrast medium (contrast FFR [cFFR]) in predicting FFR and comparing it to the performance of resting Pd/Pa in a collaborative registry of 926 patients enrolled in 10 hospitals from four European countries (Italy, Spain, France and Portugal).
METHODS AND RESULTS:
Resting Pd/Pa, cFFR and FFR were measured in 1,026 coronary stenoses functionally evaluated using commercially available pressure wires. cFFR was obtained after intracoronary injection of contrast medium, while FFR was measured after administration of adenosine. Resting Pd/Pa and cFFR were significantly higher than FFR (0.93±0.05 vs. 0.87±0.08 vs. 0.84±0.08, p<0.001). A strong correlation and a close agreement at Bland-Altman analysis between cFFR and FFR were observed (r=0.90, p<0.001 and 95% CI of disagreement: from -0.042 to 0.11). ROC curve analysis showed an excellent accuracy (89%) of the cFFR cut-off of ≤0.85 in predicting an FFR value ≤0.80 (AUC 0.95 [95% CI: 0.94-0.96]), significantly better than that observed using resting Pd/Pa (AUC: 0.90, 95% CI: 0.88-0.91; p<0.001). A cFFR/FFR hybrid approach showed a significantly lower number of lesions requiring adenosine than a resting Pd/Pa/FFR hybrid approach (22% vs. 44%, p<0.0001).
CONCLUSIONS:
cFFR is accurate in predicting the functional significance of coronary stenosis. This could allow limiting the use of adenosine to obtain FFR to a minority of stenoses with considerable savings of time and costs.info:eu-repo/semantics/publishedVersio
Alteration of the subducting oceanic lithosphere at the southern central Chile trench-outer rise
Hydrothermal circulation and brittle faulting processes affecting the oceanic lithosphere are usually confined to the upper crust for oceanic lithosphere created at intermediate to fast spreading rates. Lower crust and mantle rocks are therefore relatively dry and undeformed. However, recent studies at subduction zones suggest that hydration of the oceanic plate is most vigorous at the trench–outer rise, where extensional bending-related faulting affects the hydrogeology of the oceanic crust and mantle. To understand the degree of hydration, we studied the seismic velocity structure of the incoming Nazca plate offshore of southern central Chile (∼43°S); here the deep-sea trench is heavily filled with up to 2 km of sediments. Seismic refraction and wide-angle data, complemented by seismic reflection imaging of sediments, are used to derive a two-dimensional velocity model using joint refraction and reflection traveltime tomography. The seismic profile runs perpendicular to the spreading ridge and trench axes. The velocity model derived from the tomography inversion consists of a ∼5.3-km-thick oceanic crust and shows P wave velocities typical for mature fast spreading crust in the seaward section of the profile, with uppermost mantle velocities as fast as ∼8.3 km/s. Approaching the Chile trench, seismic velocities are significantly reduced, however, suggesting that the structures of both the oceanic crust and uppermost mantle have been altered, possibly due to a certain degree of fracturing and hydration. The decrease of the velocities roughly starts at the outer rise, ∼120 km from the deformation front, and continues into the trench. Even though the trench is filled with sediment, basement outcrops in the outer rise frequently pierce the sedimentary blanket. Anomalously low heat flow values near outcropping basement highs indicate an efficient inflow of cold seawater into the oceanic crust. Hydration and crustal cracks activated by extensional bending-related faulting are suggested to govern the reduced velocities in the vicinity of the trench. Considering typical flow distances of 50 km, water might be redistributed over most of the trench–outer rise area. Where trapped in faults, seawater may migrate down to mantle depth, causing up to ∼9% of serpentinization in at least the uppermost ∼2 km of the mantle between the outer rise and the trench axis
Horner's Syndrome due to a Spontaneous Internal Carotid Artery Dissection after Deep Sea Scuba Diving
Internal carotid artery dissection (ICAD) is a rare entity that either results from traumatic injury or can be spontaneously preceded or not by a minor trauma such as sporting activities. It represents a major cause of stroke in young patients. The diagnosis should be suspected with the combination of Horner''s syndrome, headache or neck pain, and retinal or cerebral ischaemia. The confirmation is frequently made with a magnetic resonance angiography (MRA). Although anticoagulation with heparin followed by vitamin-K-antagonists is the most common treatment, there is no difference in efficacy of antiplatelet and anticoagulant drugs at preventing stroke and death in patients with symptomatic carotid dissection. We describe a patient with ICAD following deep sea scuba diving, who presented with Horner''s syndrome and neck pain and was successfully treated with anticoagulants
Veränderung der subduzierten ozeanischen Lithosphäre am südlichen zentral-chilenischen Trench-Outer Rise
Diamond Color Centers in Diamonds for Chemical and Biochemical Analysis and Visualization
Beyond the sparkle, other properties of diamond havegained increasing attention in the past few decades amongchemists and physicists. Color centers-impurities formed byone or a few foreign atoms or vacancies in the diamondlattice-are one reason for this. While pure diamond istransparent, the presence of color centers causes changes incoloration. Color centers introduce additional electronic statesin the wide band gap of diamond, giving rise to transitions thatabsorb and emit light in the visible spectrum
Catarata pediátrica en un paÃs en vÃas de desarrollo: revisión retrospectiva de 328 casos
Structural Characterisation of Printable Noble Metal/Poly(Vinyl-ÂAlcohol) Nanocomposites for Optical Applications
This work was conducted under the aegis of the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom (EP/I004173/1). Amin Abdolvand is an EPSRC Career Acceleration Fellow at the University of Dundee.In order to enable exploitation of noble metal/poly(vinyl-alcohol) nanocomposites for device fabrication, solutions of poly(vinyl-alcohol) suitable for piezo-driven inkjet printing techniques are identified and discussed in terms of their material properties. The printable poly(vinyl-alcohol) medium is then exploited as a host material through the formation of silver or gold nanoparticles in order to create nanocomposites that exhibit a surface plasmon resonance behaviour associated with the small metallic inclusions. To mitigate some of the material redistribution effects associated with the drying of printed droplets containing finely divided materials, the metallic nanoparticles are formed after the printing and drying process is completed, by way of an in-situ reduction of an appropriate metal salt by the poly(vinyl-alcohol)-host matrix itself, which takes place at modest temperatures compatible with most substrate materials. An obvious application for such nanocomposites is in optical elements whereby the surface plasmon resonance associated with the metal is the functional aspect of devices such as sensors or active optical elements. High Resolution Transmission Electron Microscopy was used to examine the dimensions, distribution, morphology and crystal structure of the silver and gold nanoparticles in detail allowing discussion of their suitability for these applications and what further optimisation may be necessary to adequately control their formation.Publisher PDFPeer reviewe
Performance characterization and near-realtime monitoring of MUSE adaptive optics modes at Paranal
The Multi Unit Spectroscopic Explorer (MUSE) is an integral field
spectrograph on the Very Large Telescope Unit Telescope 4, capable of laser
guide star assisted and tomographic adaptive optics using the GALACSI module.
Its observing capabilities include a wide field (1 square arcmin), ground layer
AO mode (WFM-AO) and a narrow field (7.5"x7.5"), laser tomography AO mode
(NFM-AO). The latter has had several upgrades in the 4 years since
commissioning, including an optimisation of the control matrices for the AO
system and a new sub-electron noise detector for its infra-red low order
wavefront sensor. We set out to quantify the NFM-AO system performance by
analysing 230 spectrophotometric standard star observations taken over
the last 3 years. To this end we expand upon previous work, designed to
facilitate analysis of the WFM-AO system performance. We briefly describe the
framework that will provide a user friendly, semi-automated way for system
performance monitoring during science operations. We provide the results of our
performance analysis, chiefly through the measured Strehl ratio and full width
at half maximum (FWHM) of the core of the point spread function (PSF) using two
PSF models, and correlations with atmospheric conditions. These results will
feed into a range of applications, including providing a more accurate
prediction of the system performance as implemented in the exposure time
calculator, and the associated optimization of the scientific output for a
given set of limiting atmospheric conditions.Comment: SPIE proceedings (2022), Observatory Operations: Strategies,
Processes, and Systems I
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