3,178 research outputs found
Tirofiban and NSTE-ACS: The Current Perspective
Acute coronary syndromes without persistent ST segment elevation (NSTE-ACS) are common manifestations of coronary artery disease and represent one of the most important reasons for emergency medical care and hospitalisation, accounting for approximately 2.5 million hospital admissions annually worldwide Considerable progress has been made recently in the optimal management of these patients, particularly with regard to (1) the introduction of new powerful antiplatelet drugs (mainly the IIb/IIIa platelet receptor inhibitors) and (2) the demonstration that, in selected cases, an aggressive approach with early coronary angiography and percutaneous coronary interventions (PCI) can be safely performed with low risk of procedural complications and with improved in-hospital and long-term outcome. IIb/IIIa Platelet Receptor Inhibitors It has recently been shown that the addition of glycoprotein (GP) IIb/IIIa receptor inhibitors to unfractionated heparin and aspirin further improves the clinical outcome of patients with NSTE-AC
Revealing the nature of magnetic shadows with numerical 3D-MHD simulations
We investigate the interaction of magneto-acoustic waves with magnetic
network elements with the aim of finding possible signatures of the magnetic
shadow phenomenon in the vicinity of network elements. We carried out
three-dimensional numerical simulations of magneto-acoustic wave propagation in
a model solar atmosphere that is threaded by a complexly structured magnetic
field, resembling that of a typical magnetic network element and of
internetwork regions. High-frequency waves of 10 mHz are excited at the bottom
of the simulation domain. On their way through the upper convection zone and
through the photosphere and the chromosphere they become perturbed, refracted,
and converted into different mode types. We applied a standard Fourier analysis
to produce oscillatory power-maps of the line-of-sight velocity. In the power
maps of the upper photosphere and the lower chromosphere, we clearly see the
magnetic shadow: a seam of suppressed power surrounding the magnetic network
elements. We demonstrate that this shadow is linked to the mode conversion
process and that power maps at these height levels show the signature of three
different magneto-acoustic wave modes.Comment: Astronomy & Astrophysics Letters, in print 4 pages, 4 figure
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bitstream/CNPC-2010/23051/1/doc89.pd
Radiative transfer effects on Doppler measurements as sources of surface effects in sunspot seismology
We show that the use of Doppler shifts of Zeeman sensitive spectral lines to
observe wavesn in sunspots is subject to measurement specific phase shifts
arising from, (i) altered height range of spectral line formation and the
propagating character of p mode waves in penumbrae, and (ii) Zeeman broadening
and splitting. We also show that these phase shifts depend on wave frequencies,
strengths and line of sight inclination of magnetic field, and the polarization
state used for Doppler measurements. We discuss how these phase shifts could
contribute to local helioseismic measurements of 'surface effects' in sunspot
seismology.Comment: 12 pages, 4 figures, Accepted for publication in the Astrophysical
Journal Letter
Protective effects of exosomes derived from lyophilized porcine liver against acetaminophen damage on HepG2 cells
Background: Recently, extracellular vesicles have come to the fore following their emerging role in cell communication, thanks to their ability to reach cells into the human body without dissipating their cargo, transferring biological active molecules, such as proteins, nucleic acids, lipids, etc. They appear as a promising tool in medicine, because of their capability to modulate cellular response in recipient cells. Moreover, a considerable number of publications suggests that exosome uptake is selective but not specific, and it can cross species and cell-type boundaries. This study aims to explore the potential role of porcine liver derived extracellular vesicles, exosomes in particular, to protect human cells from acute damage induced by acetaminophen. Methods: Extracellular vesicles were isolated from porcine lyophilized liver using polymer-based precipitation and a further enrichment was performed using affinity beads. The effects of obtained fractions, total extracellular vesicles and enriched extracellular vesicles, were assessed on human liver derived HepG2 cells. Cell growth and survival were tested, with MTT and area coverage analysis designed by us, as well as protein expression, with immunofluorescence and Western blot. Oxidative stress in live cells was also measured with fluorogenic probes. Results: After proving that porcine extracellular vesicles did not have a toxic effect on HepG2, quite the contrary total extracellular vesicle fraction improved cell growth, we investigated their protective capability with a preconditioning strategy in APAP-induced damage. EVs displayed not only the ability to strongly modulate cell survival responses, but they also were able to boost cell cycle progression. Conclusions: Extracellular vesicles derived from farm animal food derivatives are able to modulate human hepatic cell metabolism, also improving cell survival in a damaged context
Bias Dependence of the Depletion Layer Width in Semi-Insulating GaAs by Charge Collection Scanning Microscopy
A procedure for the evaluation of the depletion region width of a Schottky barrier diode made on semi-insulating materials has been assessed and applied to gallium arsenide nuclear detectors. This procedure, which makes use of the optical beam induced current method of charge collection scanning microscopy, allows the direct measurement of the depletion layer width. By taking into account the high resistivity of the material under examination and measuring the diode reverse current, it is possible to evaluate the actual voltage applied at the depletion layer boundaries. It was found that, at low actual bias values, the voltage dependence of the depletion layer follows the usual square root power law, while at increasing voltages, it changes into a linear behavior. An explanation in terms of deep trap effect and trap field-enhanced capture cross-section is proposed even though further work must be done to explain the space charge width dependence on bias applied in terms of the deep trap influence
Breakdown at Medium Frequencies of Thermally-Aged Polyester Films
This article investigates the evolution of electrical properties of polyethylene terephthalate (PET) with thermal aging. Electrical tests are performed within a wide range of frequencies in order to simulate the application conditions of insulating materials in inverter-fed machines. In particular, for the aging conditions considered, the real part of permittivity showed to be correlated with the concentration of the degradation species, investigated through FTIR. On the contrary, the dielectric breakdown at high frequencies showed to be independent from the corresponding values of the dissipation factor (tanδ). This behavior would imply that thermal runaway is not the principal phenomenon leading to the dielectric failure
Investigation of corrosion-erosion phenomena in the primary cooling system of SPIDER
SPIDER dedicated cooling plant has to remove up to 10 MW thermal power from in-vessel components and auxiliary systems. The circuit is characterized by three main heat transfer systems: primary, secondary and tertiary systems. The primary system is made of four circuits, with only three operating so far, these are called PC01, PC02 and PC03. These three circuits respectively cool SPIDER power supplies and the beam source components using ultrapure water. During 2019 SPIDER experimental campaigns, it was observed that electrical resistivity of water degraded considerably and more quickly (∼25 MΩ cm h−1 in PC01) than estimated by design. To overcome this issue, water had to be restored very frequently to maintain the desired characteristics and avoid possible detrimental leakage currents throughout the circuit. The reason for this severe water degradation has to be better understood before issues such as abrupt failures may arise. This work presents a preliminary analysis of the two main circuits (PC01 and PC02) where an estimation of water degradation induced by general corrosion of stainless steels and copper components was made. This preliminary estimation showed that PC01 could be more prone to general corrosion than PC02; however, the rate of water conductivity increase was 5.3 times smaller than that observed during experiments in 2019 and 2020
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