5,818 research outputs found
Long time clinical outcomes of limus-eluting stent versus paclitaxel-eluting stent in patients undergoing percutaneous coronary artery intervention: A meta-analysis of randomized controlled clinical trials
Background: The meta-analysis was aimed to compare the long time (> 2 year) clinical outcomes of limus-based stents (LBS) and paclitaxel-eluting stents (PES). LBS and PES are two kinds of most common coronary artery stents in clinics.Methods: Electronic data bases of PubMed, Cochrane, and EMBASE were searched. We included randomized controlled clinical trials (RCT) comparing LBS and PES with long time clinical outcomes. Methodological quality of eligible trials was assessed using “risk of bias” tool. The efficacy endpoints included target lesion revascularization (TLR), target vessel revascularization (TVR), and stent thrombosis (ST), and the safety endpoints included all cause death, cardiac death, and myocardial infarction (MI). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for each endpoint.Results: A total of 23 RCTs and 19,319 participants were included and analyzed in this meta-analysis. All trials were of an acceptable quality. At 2 years, LBS showed reduced risk of revascularization and ST (TLR: OR = 0.59, 95% CI 0.44–0.78; TVR: OR = 0.63, 95% CI 0.55–0.71; ST: OR = 0.55, 95% CI 0.41–0.73) and a lower rate of MI (OR = 0.67, 95% CI 0.57–0.79). Subgroup analysis showed that both everolimus-eluting stents and sirolimus-eluting stents had better clinical outcomes compared with PES. The comparisons of 3, 4 and 5 year follow-up results revealed that the clinical outcomes of PES were non-inferior to those of LBS but LBS was associated with reduced risk of MI and ST at 3 years.Conclusions: LBS is associated with better clinical outcomes at 2 years. Both LBS and PES showed similar efficacy and safety at long time period.
Towards a reliable prediction of the infrared spectra of cosmic fullerenes and their derivatives in the JWST era
Fullerenes, including C60, C70, and C60+, are widespread in space through
their characteristic infrared vibrational features (C60+ also reveals its
presence in the interstellar medium through its electronic transitions) and
offer great insights into the carbon chemistry and stellar evolution. The
potential existence of fullerene-related species in space has long been
speculated and recently put forward by a set of laboratory experiments of C60+,
C60H+, C60O+, C60OH+, C70H+, and [C60-Metal]+ complexes. The advent of the
James Webb Space Telescope (JWST) provides a unique opportunity to search for
these fullerene-related species in space. To facilitate JWST search, analysis,
and interpretation, an accurate knowledge of their vibrational properties is
essential. Here, we compile a VibFullerene database and conduct a systematic
theoretical study on those species. We derive a set of range-specific scaling
factors for vibrational frequencies, to account for the deficiency of density
functional theory calculations in predicting the accurate frequencies. Scaling
factors with low root-mean-square and median errors for the frequencies are
obtained, and their performance is evaluated, from which the best-performing
methods are recommended for calculating the infrared spectra of fullerene
derivatives which balance the accuracy and computational cost. Finally, the
recommended vibrational frequencies and intensities of fullerene derivatives
are presented for future JWST detection.Comment: 19 pages, 8 figures, 5 tables. Accepted for publication in MNRA
Realizing bending waveguides with anisotropic epsilon-near-zero metamaterials
We study metamaterials with an anisotropic effective permittivity tensor in
which one component is near zero. We find that such an anisotropic metamaterial
can be used to control wave propagation and construct almost perfect bending
waveguides with a high transmission rate (>95%). This interesting effect
originates in the power flow redistribution by the surface waves on the input
and output interfaces, which smoothly matches with the propagating modes inside
the metamaterial waveguide. We also find that waves in such anisotropic
epsilon-near-zero materials can be reflected by small-sized perfect magnetic
conductor defects. Numerical calculations have been performed to confirm the
above effects
Radial Angular Momentum Transfer and Magnetic Barrier for Short-Type Gamma-Ray Burst Central Engine Activity
Soft extended emission (EE) following initial hard spikes up to 100 seconds
was observed with {\em Swift}/BAT for about half of short-type gamma-ray bursts
(SGRBs). This challenges the conversional central engine models of SGRBs, i.e.,
compact star merger models. In the framework of the black hole-neutron star
merger models, we study the roles of the radial angular momentum transfer in
the disk and the magnetic barrier around the black hole for the activity of
SGRB central engines. We show that the radial angular momentum transfer may
significantly prolong the lifetime of the accretion process and multiple
episodes may be switched by the magnetic barrier. Our numerical calculations
based on the models of the neutrino-dominated accretion flows suggest that the
disk mass is critical for producing the observed EE. In case of the mass being
, our model can reproduce the observed timescale and
luminosity of both the main and EE episodes in a reasonable parameter set. The
predicted luminosity of the EE component is lower than the observed EE with
about one order of magnitude and the timescale is shorter than 20 seconds if
the disk mass being . {\em Swift}/BAT-like instruments may
be not sensitive enough to detect the EE component in this case. We argue that
the EE component would be a probe for merger process and disk formation for
compact star mergers.Comment: 9 pages, 3 figures, accepted for publication in Ap
Pentagon, Hexagon, or Bridge? Identifying the Location of a Single Vanadium Cation on Buckminsterfullerene Surface
Buckminsterfullerene C60 has received extensive research interest ever since
its discovery. In addition to its interesting intrinsic properties of
exceptional stability and electron-accepting ability, the broad chemical
tunability by decoration or substitution on the C60-fullerene surface makes it
a fascinating molecule. However, to date there is uncertainty about the binding
location of such decorations on the C60 surface, even for a single adsorbed
metal atom. In this work, we report the gas-phase synthesis of the C60V+
complex and its in-situ characterization by mass spectrometry and in-frared
spectroscopy with the help of quantum chemical calculations and molecular
dynamics simulations. We identify the most probable binding position of a
vanadium cation on C60 above a pentagon center in eta5-fashion, demonstrate a
high thermal stability for this complex, and explore the bonding nature between
C60 and the vanadium cation, reveal-ing that large orbital and electrostatic
interactions lie at the origin of the stability of the eta5-C60V+ complex.Comment: 29 pages (11 pages for main text and 17 pages for the supporting
information
Tunable superluminal propagation at spectral hole-burning regions in magneto-optical atomic medium
In the context of spectral hole-burning, normal dispersion with subluminal propagation is usually observed in the spectral hole-burning depth region. However, anomalous dispersion can occur in the continuous absorption peak region, which leads to superluminal light propagation. In this paper, we report an unusual behavior of dispersion at discontinued absorption kink regions. We demonstrate both normal dispersion at the kink absorption region and anomalous dispersion at the spectral hole-burning depth region. The unusual dispersion leads to a positive group index in the absorption kink region and a negative group index in the spectral hole-burning depth region. The spectral hole-burning is due to variation of magnetization rather than the molecular distribution. The outcomes of our work offer promising applications in communication technologies and storage devices
ConstGCN: Constrained Transmission-based Graph Convolutional Networks for Document-level Relation Extraction
Document-level relation extraction with graph neural networks faces a
fundamental graph construction gap between training and inference - the golden
graph structure only available during training, which causes that most methods
adopt heuristic or syntactic rules to construct a prior graph as a pseudo
proxy. In this paper, we propose , a novel graph
convolutional network which performs knowledge-based information propagation
between entities along with all specific relation spaces without any prior
graph construction. Specifically, it updates the entity representation by
aggregating information from all other entities along with each relation space,
thus modeling the relation-aware spatial information. To control the
information flow passing through the indeterminate relation spaces, we propose
to constrain the propagation using transmitting scores learned from the Noise
Contrastive Estimation between fact triples. Experimental results show that our
method outperforms the previous state-of-the-art (SOTA) approaches on the DocRE
dataset
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