27 research outputs found
Superconducting fluctuations and charge-4 plaquette state at strong coupling
Recent experiments indicate that superconducting fluctuations also play an
important role in overdoped cuprates. Here we apply the static auxiliary field
Monte Carlo approach to study phase correlations of the pairing fields in a
microscopic model with spin-singlet pairing interaction. We find that the
short- and long-range phase correlations are well captured by the phase mutual
information, which allows us to construct a theoretical phase diagram
containing the uniform -wave superconducting region, the phase fluctuating
region, the local pairing region, and the disordered region. We show that the
gradual development of phase coherence has a number of consequences on
spectroscopic measurements, such as the development of the Fermi arc and the
anisotropy in the angle-resolved spectra, scattering rate, entropy, specific
heat, and quasiparticle dispersion, in good agreement with experimental
observations. For strong coupling, our Monte Carlo simulation reveals an
unexpected charge-4 plaquette state with -wave bonds, which competes with
the uniform -wave superconductivity and exhibits a U-shaped density of
states
Energy landscape and phase competition of CsV3Sb5-, CsV6Sb6-, and TbMn6Sn6-type Kagome materials
Finding viable Kagome lattices is vital for materializing novel phenomena in
quantum materials. In this work, we performed element substitutions on CsV3Sb5
with space group P6/mmm, TbMn6Sn6 with space group P6/mmm, and CsV6Sb6 with
space group R-3 m, respectively, as the parent compounds. A total of 4158
materials were obtained through element substitutions, and these materials were
then calculated via density function theory in high-throughput mode. Afterward,
48 materials were identified with high thermodynamic stability
(E_hull<5meV/atom). Furthermore, we compared the thermodynamic stability of
three different phases with the same elemental composition and predicted some
competing phases that may arise during material synthesis. Finally, by
calculating the electronic structures of these materials, we attempted to
identify patterns in the electronic structure variations as the elements
change. This work provides guidance for discovering promising AM3X5/AM6X6
Kagome materials from a vast phase space
High-energy magnetic excitations from heavy quasiparticles in CeCuSi
Magnetic fluctuations is the leading candidate for pairing in cuprate,
iron-based and heavy fermion superconductors. This view is challenged by the
recent discovery of nodeless superconductivity in CeCuSi, and calls for
a detailed understanding of the corresponding magnetic fluctuations. Here, we
mapped out the magnetic excitations in \ys{superconducting (S-type)}
CeCuSi using inelastic neutron scattering, finding a strongly
asymmetric dispersion for ~meV, which at higher energies evolve
into broad columnar magnetic excitations that extend to meV. While
low-energy magnetic excitations exhibit marked three-dimensional
characteristics, the high-energy magnetic excitations in CeCuSi are
almost two-dimensional, reminiscent of paramagnons found in cuprate and
iron-based superconductors. By comparing our experimental findings with
calculations in the random-phase approximation,we find that the magnetic
excitations in CeCuSi arise from quasiparticles associated with its
heavy electron band, which are also responsible for superconductivity. Our
results provide a basis for understanding magnetism and superconductivity in
CeCuSi, and demonstrate the utility of neutron scattering in probing
band renormalization in heavy fermion metals
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
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Extensive sequencing of seven human genomes to characterize benchmark reference materials
The Genome in a Bottle Consortium, hosted by the National Institute of Standards and Technology (NIST) is creating reference materials and data for human genome sequencing, as well as methods for genome comparison and benchmarking. Here, we describe a large, diverse set of sequencing data for seven human genomes; five are current or candidate NIST Reference Materials. The pilot genome, NA12878, has been released as NIST RM 8398. We also describe data from two Personal Genome Project trios, one of Ashkenazim Jewish ancestry and one of Chinese ancestry. The data come from 12 technologies: BioNano Genomics, Complete Genomics paired-end and LFR, Ion Proton exome, Oxford Nanopore, Pacific Biosciences, SOLiD, 10X Genomics GemCode WGS, and Illumina exome and WGS paired-end, mate-pair, and synthetic long reads. Cell lines, DNA, and data from these individuals are publicly available. Therefore, we expect these data to be useful for revealing novel information about the human genome and improving sequencing technologies, SNP, indel, and structural variant calling, and de novo assembly
Application of a Bentonite Slurry Modified by Polyvinyl Alcohol in the Cutoff of a Landfill
Soil-bentonite cutoff walls are usually used to contain the contaminants of landfills. The pumpability, permeability, and adsorption capability of the slurry are all crucial to the performance of the cutoff wall. In this study, the effect of polyvinyl alcohol (PVA) was used to improve the performance of bentonite slurry. A series of lab tests were conducted to evaluate the pumpability, permeability, and adsorption capacity with different concentrations of PVA treatment. Results show that the addition of PVA can increase the fluidity and pumpable period of slurry, which facilitates the casting and grouting during construction. The addition of PVA also helps to reduce the permeability coefficient of slurry and improve the adsorption capability which enhances the cutoff performance of the walls
Predicting the cognitive function status in end-stage renal disease patients at a functional subnetwork scale
Brain functional networks derived from functional magnetic resonance imaging (fMRI) provide a promising approach to understanding cognitive processes and predicting cognitive abilities. The topological attribute parameters of global networks are taken as the features from the overall perspective. It is constrained to comprehend the subtleties and variances of brain functional networks, which fell short of thoroughly examining the complex relationships and information transfer mechanisms among various regions. To address this issue, we proposed a framework to predict the cognitive function status in the patients with end-stage renal disease (ESRD) at a functional subnetwork scale (CFSFSS). The nodes from different network indicators were combined to form the functional subnetworks. The area under the curve (AUC) of the topological attribute parameters of functional subnetworks were extracted as features, which were selected by the minimal Redundancy Maximum Relevance (mRMR). The parameter combination with improved fitness was searched by the enhanced whale optimization algorithm (E-WOA), so as to optimize the parameters of support vector regression (SVR) and solve the global optimization problem of the predictive model. Experimental results indicated that CFSFSS achieved superior predictive performance compared to other methods, by which the mean absolute error (MAE), mean absolute percentage error (MAPE), and root mean square error (RMSE) were up to 0.5951, 0.0281 and 0.9994, respectively. The functional subnetwork effectively identified the active brain regions associated with the cognitive function status, which offered more precise features. It not only helps to more accurately predict the cognitive function status, but also provides more references for clinical decision-making and intervention of cognitive impairment in ESRD patients
Essential roles of EphrinB2 in mammalian heart: from development to diseases
Abstract EphrinB2, a membrane-tethered ligand preferentially binding to its receptor EphB4, is ubiquitously expressed in all mammals. Through the particular bidirectional signaling, EphrinB2 plays a critical role during the development of cardiovascular system, postnatal angiogenesis physiologically and pathologically, and cardiac remodeling after injuries as an emerging role. This review highlights the pivotal involvement of EphrinB2 in heart, from developmental cardiogenesis to pathological cardiac remodeling process. Further potential translational therapies will be discussed in targeting EphrinB2 signaling, to better understand the prevention and treatment of cardiovascular diseases