307 research outputs found
Chern insulators and high Curie temperature Dirac half-metal in two-dimensional metal-organic frameworks
Two-dimensional (2D) magnetic materials with nontrivial topological states
have drawn considerable attention recently. Among them, 2D metal-organic
frameworks (MOFs) are standing out due to their advantages, such as the easy
synthesis in practice and less sensitivity to oxidation that are distinctly
different from inorganic materials. By means of density-functional theory
calculations, we systematically investigate the electronic and topological
properties of a class of 2D MOFs X(C21H15N3) (X = transition metal element from
3d to 5d). Excitingly, we find that X(C21H15N3) (X = Ti, Zr, Ag, Au) are Chern
insulators with sizable band gaps (~7.1 meV). By studying a four-band effective
model, it is revealed that the Chern insulator phase in X(C21H15N3) (X = Ti,
Zr, Ag, Au) is caused cooperatively by the band inversion of the p orbitals of
the C21H15N3 molecule and the intrinsic ferromagnetism of X(C21H15N3).
Additionally, Mn(C21H15N3) is a Dirac half-metal ferromagnet with a high Curie
temperature up to 156 K. Our work demonstrates that 2D MOFs X(C21H15N3) are
good platforms for realizing Quantum anomalous Hall effect and designing novel
spintronic devices based on half-metals with high-speed and long-distance spin
transport.Comment: 16 pages, 4 figure
Amelioration of Inflammatory Cytokines Mix Stimulation: A Pretreatment of CD137 Signaling Study on VSMC
Highly Selective Production of Ethylene by the Electroreduction of Carbon Monoxide.
Conversion of carbon monoxide to high value-added ethylene with high selectivity by traditional syngas conversion process is challenging because of the limitation of Anderson-Schulz-Flory distribution. Herein we report a direct electrocatalytic process for highly selective ethylene production from CO reduction with water over Cu catalysts at room temperature and ambient pressure. An unprecedented 52.7 % Faradaic efficiency of ethylene formation is achieved through optimization of cathode structure to facilitate CO diffusion at the surface of the electrode and Cu catalysts to enhance the C-C bond coupling. The highly selective ethylene production is almost without other carbon-based byproducts (e.g. C1 -C4 hydrocarbons and CO2 ) and avoids the drawbacks of the traditional Fischer-Tropsch process that always delivers undesired products. This study provides a new and promising strategy for highly selective production of ethylene from the abundant industrial CO
Orbital-Dependent Electron Correlation in Double-Layer Nickelate La3Ni2O7
The latest discovery of high temperature superconductivity near 80K in
La3Ni2O7 under high pressure has attracted much attention. Many proposals are
put forth to understand the origin of superconductivity. The determination of
electronic structures is a prerequisite to establish theories to understand
superconductivity in nickelates but is still lacking. Here we report our direct
measurement of the electronic structures of La3Ni2O7 by high-resolution
angle-resolved photoemmission spectroscopy. The Fermi surface and band
structures of La3Ni2O7 are observed and compared with the band structure
calculations. A flat band is formed from the Ni-3dz2 orbitals around the zone
corner which is 50meV below the Fermi level. Strong electron correlations are
revealed which are orbital- and momentum-dependent. Our observations will
provide key information to understand the origin of high temperature
superconductivity in La3Ni2O7.Comment: 18 pages, 4 figure
The LAMOST Survey of Background Quasars in the Vicinity of the Andromeda and Triangulum Galaxies -- II. Results from the Commissioning Observations and the Pilot Surveys
We present new quasars discovered in the vicinity of the Andromeda and
Triangulum galaxies with the LAMOST during the 2010 and 2011 observational
seasons. Quasar candidates are selected based on the available SDSS, KPNO 4 m
telescope, XSTPS optical, and WISE near infrared photometric data. We present
509 new quasars discovered in a stripe of ~135 sq. deg from M31 to M33 along
the Giant Stellar Stream in the 2011 pilot survey datasets, and also 17 new
quasars discovered in an area of ~100 sq. deg that covers the central region
and the southeastern halo of M31 in the 2010 commissioning datasets. These 526
new quasars have i magnitudes ranging from 15.5 to 20.0, redshifts from 0.1 to
3.2. They represent a significant increase of the number of identified quasars
in the vicinity of M31 and M33. There are now 26, 62 and 139 known quasars in
this region of the sky with i magnitudes brighter than 17.0, 17.5 and 18.0
respectively, of which 5, 20 and 75 are newly-discovered. These bright quasars
provide an invaluable collection with which to probe the kinematics and
chemistry of the ISM/IGM in the Local Group of galaxies. A total of 93 quasars
are now known with locations within 2.5 deg of M31, of which 73 are newly
discovered. Tens of quasars are now known to be located behind the Giant
Stellar Stream, and hundreds behind the extended halo and its associated
substructures of M31. The much enlarged sample of known quasars in the vicinity
of M31 and M33 can potentially be utilized to construct a perfect astrometric
reference frame to measure the minute PMs of M31 and M33, along with the PMs of
substructures associated with the Local Group of galaxies. Those PMs are some
of the most fundamental properties of the Local Group.Comment: 26 pages, 6 figures, AJ accepte
Identification of Mouse Serum miRNA Endogenous References by Global Gene Expression Profiles
MicroRNAs (miRNAs) are recently discovered small non-coding RNAs and can serve as serum biomarkers for disease diagnosis and prognoses. Lack of reliable serum miRNA endogenous references for normalization in miRNA gene expression makes single miRNA assays inaccurate. Using TaqMan® real-time PCR miRNA arrays with a global gene expression normalization strategy, we have analyzed serum miRNA expression profiles of 20 female mice of NOD/ShiLtJ (n = 8), NOR/LtJ (n = 6), and C57BL/6J (n = 6) at different ages and disease conditions. We identified five miRNAs, miR-146a, miR-16, miR-195, miR-30e and miR-744, to be stably expressed in all strains, which could serve as mouse serum miRNA endogenous references for single assay experiments
Elevated transcriptional levels of aldolase A (ALDOA) associates with cell cycle-related genes in patients with NSCLC and several solid tumors
Elevated C1orf63 expression is correlated with CDK10 and predicts better outcome for advanced breast cancers: a retrospective study
Clopidogrel Plus Aspirin vs Aspirin Alone in Patients With Acute Mild to Moderate Stroke
Importance
Dual antiplatelet therapy has been demonstrated to be superior to single antiplatelet in reducing recurrent stroke among patients with transient ischemic attack or minor stroke, but robust evidence for its effect in patients with mild to moderate ischemic stroke is lacking.
Objective
To evaluate whether dual antiplatelet therapy is superior to single antiplatelet among patients with mild to moderate ischemic stroke.
Design, Setting, and Participants
This was a multicenter, open-label, blinded end point, randomized clinical trial conducted at 66 hospitals in China from December 20, 2016, through August 9, 2022. The date of final follow-up was October 30, 2022. The analysis was reported on March 12, 2023. Of 3065 patients with ischemic stroke, 3000 patients with acute mild to moderate stroke within 48 hours of symptom onset were enrolled, after excluding 65 patients who did not meet eligibility criteria or had no randomization outcome.
Interventions
Within 48 hours after symptom onset, patients were randomly assigned to receive clopidogrel plus aspirin (n = 1541) or aspirin alone (n = 1459) in a 1:1 ratio.
Main Outcomes and Measures
The primary end point was early neurologic deterioration at 7 days, defined as an increase of 2 or more points in National Institutes of Health Stroke Scale (NIHSS) score, but not as a result of cerebral hemorrhage, compared with baseline. The superiority of clopidogrel plus aspirin to aspirin alone was assessed based on a modified intention-to-treat population, which included all randomized participants with at least 1 efficacy evaluation regardless of treatment allocation. Bleeding events were safety end points.
Results
Of the 3000 randomized patients, 1942 (64.6%) were men, the mean (SD) age was 65.9 (10.6) years, median (IQR) NIHSS score at admission was 5 (4-6), and 1830 (61.0%) had a stroke of undetermined cause. A total of 2915 patients were included in the modified intention-to-treat analysis. Early neurologic deterioration occurred in 72 of 1502 (4.8%) in the dual antiplatelet therapy group vs 95 of 1413 (6.7%) in the aspirin alone group (risk difference −1.9%; 95% CI, −3.6 to −0.2; P = .03). Similar bleeding events were found between 2 groups.
Conclusions and Relevance
Among Chinese patients with acute mild to moderate ischemic stroke, clopidogrel plus aspirin was superior to aspirin alone with regard to reducing early neurologic deterioration at 7 days with similar safety profile. These findings indicate that dual antiplatelet therapy may be a superior choice to aspirin alone in treating patients with acute mild to moderate stroke.Trial RegistrationClinicalTrials.gov Identifier: NCT0286900
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Joint analysis of three genome-wide association studies of esophageal squamous cell carcinoma in Chinese populations
We conducted a joint (pooled) analysis of three genome-wide association studies (GWAS) 1-3 of esophageal squamous cell carcinoma (ESCC) in ethnic Chinese (5,337 ESCC cases and 5,787 controls) with 9,654 ESCC cases and 10,058 controls for follow-up. In a logistic regression model adjusted for age, sex, study, and two eigenvectors, two new loci achieved genome-wide significance, marked by rs7447927 at 5q31.2 (per-allele odds ratio (OR) = 0.85, 95% CI 0.82-0.88; P=7.72x10−20) and rs1642764 at 17p13.1 (per-allele OR= 0.88, 95% CI 0.85-0.91; P=3.10x10−13). rs7447927 is a synonymous single nucleotide polymorphism (SNP) in TMEM173 and rs1642764 is an intronic SNP in ATP1B2, near TP53. Furthermore, a locus in the HLA class II region at 6p21.32 (rs35597309) achieved genome-wide significance in the two populations at highest risk for ESSC (OR=1.33, 95% CI 1.22-1.46; P=1.99x10−10). Our joint analysis identified new ESCC susceptibility loci overall as well as a new locus unique to the ESCC high risk Taihang Mountain region
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