2,230 research outputs found
Pressure-induced one-dimensional oxygen ion diffusion channel in lead-apatite
Recently, Lee et al. claimed that the experimental observation of
room-temperature ambient-pressure superconductivity in a Cu-doped lead-apatite
(Pb10-xCux(PO4)6O). The study revealed the Cu doping induces a chemical
pressure, resulting in a structural contraction of one-dimensional Cu-O-Cu
atomic column. This unique structure promotes a one-dimensional electronic
conduction channel along the c-axis mediated by the O atoms, which may be
related to superconductivity. These O atoms occupy 1/4 of the equivalent
positions along the c-axis and exhibit a low diffusion activation energy of 0.8
eV, indicating the possibility of diffusion between these equivalent positions.
Here, using machine-learning based deep potential, we predict the
pressure-induced fast diffusion of 1/4-occupied O atoms along the
one-dimensional channel in Pb10(PO4)6O at 500 K, while the frameworks of Pb
triangles and PO4 tetrahedrons remain stable. The calculation results also
indicate Cu doping can provide appropriate effective chemical pressure,
indicating the one-dimensional ion diffusion channel may appear in
Pb9Cu(PO4)6O, even at ambient pressure. Our finding shows that the
one-dimensional ions diffusion channel may be an important factor to affects
the fabrication and electrical measurement of doped lead-apatite.Comment: 15 pages, 7 figure
Uncertainty-Guided Spatial Pruning Architecture for Efficient Frame Interpolation
The video frame interpolation (VFI) model applies the convolution operation
to all locations, leading to redundant computations in regions with easy
motion. We can use dynamic spatial pruning method to skip redundant
computation, but this method cannot properly identify easy regions in VFI tasks
without supervision. In this paper, we develop an Uncertainty-Guided Spatial
Pruning (UGSP) architecture to skip redundant computation for efficient frame
interpolation dynamically. Specifically, pixels with low uncertainty indicate
easy regions, where the calculation can be reduced without bringing undesirable
visual results. Therefore, we utilize uncertainty-generated mask labels to
guide our UGSP in properly locating the easy region. Furthermore, we propose a
self-contrast training strategy that leverages an auxiliary non-pruning branch
to improve the performance of our UGSP. Extensive experiments show that UGSP
maintains performance but reduces FLOPs by 34%/52%/30% compared to baseline
without pruning on Vimeo90K/UCF101/MiddleBury datasets. In addition, our method
achieves state-of-the-art performance with lower FLOPs on multiple benchmarks.Comment: ACM Multimedia 202
Atomistic simulations of thermodynamic properties of liquid gallium from first principles
In the research of condensed matter, atomistic dynamic simulations play a
crucial role, particularly in revealing dynamic processes, phase transitions
and thermodynamic statistics macroscopic physical properties in systems such as
solids and liquids. For a long time, simulating complex and disordered liquids
has been a challenge compared to ordered crystalline structures. The primary
reasons for this challenge are the lack of precise force field functions and
the neglect of nuclear quantum effects. To overcome these two limits in
simulation of liquids, we use a deep potential (DP) with quantum thermal bath
(QTB) approach. DP is a machine learning model are sampled from density
functional theory and able to do large-scale atomic simulations with its
precision. QTB is a method which incorporates nuclear quantum effects by
quantum fluctuation dissipation. The application of this first principles
approach enable us to successfully describe the phase transition processes in
solid and liquid Gallium (Ga) as well as the associated dynamic phenomena. More
importantly, we obtain the thermodynamic properties of liquid Ga, such as
internal energy, specific heat, enthalpy change, entropy and Gibbs free energy,
and these results align remarkably well with experiments. Our research has
opened up a new paradigm for the study of dynamics and thermodynamics in
liquids, amorphous materials, and other disordered systems, providing valuable
insights and references for future investigations.Comment: 7 pages, 11 figures for maintext; 6pages, 8 figures for supplementary
material
Current trends in the surgical management of Dupuytren’s disease in Europe: the surgeon’s perspective
Potential super-hard Osmium di-nitride with fluorite structure: First-principles calculations
We have performed systematic first-principles calculations on di-carbide,
-nitride, -oxide and -boride of platinum and osmium with the fluorite
structure. It is found that only PtN, OsN and OsO are
mechanically stable. In particular OsN has the highest bulk modulus of
360.7 GPa. Both the band structure and density of states show that the new
phase of OsN is metallic. The high bulk modulus is owing to the strong
covalent bonding between Os 5\textit{d} and N 2\textit{p} states and the dense
packed fluorite structure.Comment: Phys. Rev. B 74,125118 (2006
Clinical characteristics of bloodstream infections due to ampicillin-sulbactam-resistant, non-extended-spectrum-β-lactamase-producing Escherichia coli and the role of TEM-1 hyperproduction
Ampicillin-sulbactam is commonly used as an empirical therapy for invasive infections where Escherichia coli is a potential pathogen. We evaluated the clinical and microbiologic characteristics of bloodstream infection due to E. coli, with focus on cases that were nonsusceptible to ampicillin-sulbactam and not producing extended-spectrum beta-lactamase (ESBL). Of a total of 357 unique bacteremic cases identified between 2005 and 2008, 111 (31.1%) were intermediate or resistant to ampicillin-sulbactam by disk testing. In multivariate analysis, a history of liver disease, organ transplant, peptic ulcer disease, and prior use of ampicillin-sulbactam were independent risk factors for bloodstream infection with ampicillin-sulbactam-nonsusceptible E. coli. Among cases that received ampicillin-sulbactam as an empirical therapy, an early clinical response was observed in 65% (22/34) of susceptible cases but in only 20% (1/5) of nonsusceptible cases. Among 50 ampicillin-sulbactam-resistant isolates examined, there was no clonal relatedness and no evidence of production of inhibitor-resistant TEM (IRT). Instead, the resistance was attributed to hyperproduction of TEM-1 beta-lactamase in the majority of isolates. However, promoter sequences of bla(TEM-1) did not predict resistance to ampicillin-sulbactam. While the plasmid copy number did not differ between representative resistant and susceptible isolates, the relative expression of bla(TEM-1) was significantly higher in two of three resistant isolates than in three susceptible isolates. These results suggest high-level bla(TEM-1) expression as the predominant cause of ampicillin-sulbactam resistance and also the presence of yet-unidentified factors promoting overexpression of bla(TEM-1) in these isolates
Different endoscopic treatments for small colorectal polyps: A systematic review, pair-wise, and network meta-analysis
Background and study aimsIn recent years, cold snare polypectomy (CSP) has been increasingly used for small polyps (<10 mm) instead of hot snare polypectomy (HSP). However, evidence-based research regarding the effectiveness and safety of CSP and HSP are still lacking. Additionally, for 4–10 -mm non-pedunculated polyps, the polyp removal method is still controversial. Therefore, it is clinically significant to conduct pair-wise and network meta-analyses to assess such resection methods.MethodsWe searched PubMed, Embase, and the Cochrane library for randomized controlled trials (RCTs). Only studies that involved the resection of polyps <10 mm were included. Outcomes included the complete resection rate, polyp retrieval rate, procedure-related complications, and procedure times.ResultsOverall, 23 RCTs (5,352 patients) were identified. In meta-analysis compared CSP versus HSP for polyps <10 mm, CSP showed lower complete resection rate than HSP although with no statistically significant difference [odds ratio (OR): 0.77, 95% confidence interval (CI): 0.56–1.06]. CSP showed a lower risk of major post-polypectomy complications compared to HSP (OR: 0.28, 95% CI: 0.11–0.73). In the network meta-analysis for 4–10 mm non-pedunculated polyps, HSP, and endoscopic mucosal resection (EMR) showed a higher complete resection rate than CSP (OR: 2.7, 95% CI: 1.3–9.2 vs. OR: 2.6, 95% CI: 1.0–10) but a significantly longer time than CSP (WMD: 16.55 s, 95% CI [7.48 s, 25.25 s], p < 0.001), (WMD: 48.00 s, 95% CI [16.54 s, 79.46 s], p = 0.003). Underwater CSP ranked third for complete resection with no complications.ConclusionFor <10 mm polyps, CSP is safer than HSP, especially for patients taking antithrombotic drugs. For 4–10 mm non-pedunculated polyps, HSP, and EMR have higher complete resection rates than CSP.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022315575
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