10,770 research outputs found
Newly developed post-operative atrial fibrillation is associated with an increased risk of late recurrence of atrial fibrillation in patients who underwent open heart surgery: Long-term follow up
Background: Herein is sought to determine whether the occurrence of post-operative atrial fibrillation (POAF) increases the risk of late recurrence of atrial fibrillation (AF) in patients undergoing open heart surgery (OHS).
Methods: This study included 938 patients (56.7 Ā± 13.1 years old, 550 males) with no history of AF who underwent OHS. All patients were monitored continuously for development of POAF after surgery until the time of hospital discharge and received clinical follow up with serial evaluation of rhythm status.
Results: Among the total population, POAF occurred in 207 (22.1%) patients and late AF in 88 (9.4%) patients during the mean follow up period of 78.1 Ā± 39.1 months. Development of late AF ocĀ¬curred more frequently in patients with POAF than in those without [29.0% (60/207) vs. 3.8% (28/731), p < 0.01]. Higher septal E/eā ratio (HR 1.04, 95% CI 1.00ā1.08, p = 0.04) was an independent predicĀ¬tor of late occurrence of AF and an episode of POAF (HR 27.12, 95% CI 8.46ā86.96, p < 0.01) was the most powerful predictor.
Conclusions: POAF is significantly associated with an increased risk of late AF recurrence during long-term follow up. Careful concern regarding late recurrence of AF with serial evaluation of rhythm status is required in patients with POAF
Machine-learning-assisted analysis of transition metal dichalcogenide thin-film growth
In situ reflective high-energy electron diffraction (RHEED) is widely used to
monitor the surface crystalline state during thin-film growth by molecular beam
epitaxy (MBE) and pulsed laser deposition. With the recent development of
machine learning (ML), ML-assisted analysis of RHEED videos aids in
interpreting the complete RHEED data of oxide thin films. The quantitative
analysis of RHEED data allows us to characterize and categorize the growth
modes step by step, and extract hidden knowledge of the epitaxial film growth
process. In this study, we employed the ML-assisted RHEED analysis method to
investigate the growth of 2D thin films of transition metal dichalcogenides
(ReSe2) on graphene substrates by MBE. Principal component analysis (PCA) and
K-means clustering were used to separate statistically important patterns and
visualize the trend of pattern evolution without any notable loss of
information. Using the modified PCA, we could monitor the diffraction intensity
of solely the ReSe2 layers by filtering out the substrate contribution. These
findings demonstrate that ML analysis can be successfully employed to examine
and understand the film-growth dynamics of 2D materials. Further, the ML-based
method can pave the way for the development of advanced real-time monitoring
and autonomous material synthesis techniques.Comment: 21 pages, 4 figure
The fermi arc and fermi pocket in cuprates in a short-range diagonal stripe phase
In this paper we studied the fermi arc and the fermi pocket in cuprates in a
short-range diagonal stripe phase with wave vectors , which
reproduce with a high accuracy the positions and sizes of the fermi arc and
fermi pocket and the superstructure in cuprates observed by Meng et
al\cite{Meng}. The low-energy spectral function indicates that the fermi pocket
results from the main band and the shadow band at the fermi energy. Above the
fermi energy the shadow band gradually departs away from the main band, leaving
a fermi arc. Thus we conclude that the fermi arc and fermi pocket can be fully
attributed to the stripe phase but has nothing to do with pairing.
Incorporating a d-wave pairing potential in the stripe phase the spectral
weight in the antinodal region is removed, leaving a clean fermi pocket in the
nodal region.Comment: 5 pages, 6 figure
Co-delivery of siRNAs and anti-cancer drugs using layered double hydroxide nanoparticles
In this research we employed layered double hydroxide nanoparticles (LDHs) to simultaneously deliver an anticancer drug 5-fluorouracil (5-FU) and Allstars Cell Death siRNA (CD-siRNA) for effective cancer treatment. The strategy takes advantage of the LDH anion exchange capacity to intercalate 5-FU into its interlayer spacing and load siRNA on the surface of LDH nanoparticles. LDH nanoparticles have been previously demonstrated as an effective cellular delivery system for 5-FU and siRNA separately in various investigations. More excitedly, the combination of CD-siRNA and anticancer drug 5-FU with the same LDH particles significantly enhanced cytotoxicity to three cancer cell lines, e.g. MCF-7, U2OS and HCT-116, compared to the single treatment with either CD-siRNA or 5-FU. This enhancement is probably a result of coordinate mitochondrial damage process. Thus, the strategy to co-deliver siRNA and an anticancer drug by LDHs has great potential to overcome the drug resistance and enhance cancer treatment
Universal Transfer of 2D Materials Grown on Au Substrate Using Sulfur Intercalation
Herein, we report on a novel method for transferring two-dimensional (2D) materials grown on Au substrates using sulfur intercalation between the 2D materials and the Au surfaces. The strong nature of the S???Au bond allows intercalation of sulfur atoms into their interface, under a sulfurrich atmosphere, at 600 ???C. The relaxed interfacial interaction achieved via intercalation is carefully confirmed by recovering phonon mode and work function of tungsten disulfide (WS2) in Raman spectra and Kelvin probe force microscopy, and, more importantly, by observing the expansion of the interfacial distance, from 0.24 to 0.44 nm, using cross-sectional transmission electron microscopy. The released interactions facilitate delamination of WS2 from the Au surface, using an electrochemical bubbling method. The resultant Au foil then is reused for repeated WS2 growth. The successful transfer of other 2D materials, including molybdenum disulfide and hexagonal boron nitride, is also demonstrated.
Our strategy advances the use of Au substrates for growing wafer-scale 2D monolayers
Bipolar resistive switching characteristics of poly(3,4-ethylene-dioxythiophene): poly(styrenesulfonate) thin film
We investigated the reversible resistive switching of
poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) thin films
sandwiched between Al electrodes. The J-V sweep curve showed a hysteretic
behavior which depends on the polarity of the applied voltage bias. From the
analysis of I-V curves, it was revealed that the charge transport through the
junction was governed by the bulk space-charge-limited conduction (SCLC) model.
Using transmission electron microscopy (TEM) analysis, it was confirmed that
the initial high resistance state of PEDOT:PSS films is related with the
segregation of PSS- chains induced by redox reaction between a Al metal
electrode and PEDOT:PSS film. Positive space charges present on the top region
of PEDOT:PSS films can be proposed as a possible trap centers of electron
trapping and detrapping process.Comment: 10 pages, 4 figure
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