101 research outputs found
Extracting the Quantum Geometric Tensor of an Optical Raman Lattice by Bloch State Tomography
In Hilbert space, the geometry of the quantum state is identified by the
quantum geometric tensor (QGT), whose imaginary part is the Berry curvature and
real part is the quantum metric tensor. Here, we propose and experimentally
implement a complete Bloch state tomography to directly measure eigenfunction
of an optical Raman lattice for ultracold atoms. Through the measured
eigenfunction, the distribution of the complete QGT in the Brillouin zone is
reconstructed, with which the topological invariants are extracted by the Berry
curvature and the distances of quantum states in momentum space are measured by
the quantum metric tensor. Further, we experimentally test a predicted
inequality between the Berry curvature and quantum metric tensor, which reveals
a deep connection between topology and geometry
Tuning anomalous Floquet topological bands with ultracold atoms
The Floquet engineering opens the way to create new topological states
without counterparts in static systems. Here, we report the experimental
realization and characterization of new anomalous topological states with
high-precision Floquet engineering for ultracold atoms trapped in a shaking
optical Raman lattice. The Floquet band topology is manipulated by tuning the
driving-induced band crossings referred to as band inversion surfaces (BISs),
whose configurations fully characterize the topology of the underlying states.
We uncover various exotic anomalous topological states by measuring the
configurations of BISs which correspond to the bulk Floquet topology. In
particular, we identify an unprecedented anomalous Floquet valley-Hall state
that possesses anomalous helicallike edge modes protected by valleys and a
chiral state with high Chern number
Design & Optimization of the HV divider for JUNO 20-inch PMT
The Jiangmen Underground Observatory (JUNO) is a 20-kton liquid scintillator
detector that employs 20,000 20-inch photomultiplier tubes (PMTs) as photon
sensors, with 5,000 dynode-PMTs from HAMAMATSU Photonics K.K. (HPK), and 15,000
MCP-PMTs from North Night Vision Technology (NNVT) installed in pure water.
JUNO aims to provide long-lasting and the best performance operation by
utilizing a high-transparency liquid scintillator, high detection efficiency
PMTs, and specially designed electronics including water-proof potting for the
high voltage (HV) dividers of PMTs. In this paper, we present a summary of the
design and optimization of HV dividers for both types of 20-inch PMTs, which
includes collection efficiency, charge resolution, HV divider current, pulse
shape, and maximum amplitude restriction. We have developed and finalized four
schemes of the HV divider for different scenarios, including the final version
selected by JUNO. All 20,000 20-inch PMTs have successfully undergone
production and burning tests.Comment: 14pages,28figure
Association of Insulin Resistance with Glucose and Lipid Metabolism: Ethnic Heterogeneity in Far Western China
Genomewide association study of leprosy.
BACKGROUND: The narrow host range of Mycobacterium leprae and the fact that it is refractory to growth in culture has limited research on and the biologic understanding of leprosy. Host genetic factors are thought to influence susceptibility to infection as well as disease progression. METHODS: We performed a two-stage genomewide association study by genotyping 706 patients and 1225 controls using the Human610-Quad BeadChip (Illumina). We then tested three independent replication sets for an association between the presence of leprosy and 93 single-nucleotide polymorphisms (SNPs) that were most strongly associated with the disease in the genomewide association study. Together, these replication sets comprised 3254 patients and 5955 controls. We also carried out tests of heterogeneity of the associations (or lack thereof) between these 93 SNPs and disease, stratified according to clinical subtype (multibacillary vs. paucibacillary). RESULTS: We observed a significant association (P<1.00x10(-10)) between SNPs in the genes CCDC122, C13orf31, NOD2, TNFSF15, HLA-DR, and RIPK2 and a trend toward an association (P=5.10x10(-5)) with a SNP in LRRK2. The associations between the SNPs in C13orf31, LRRK2, NOD2, and RIPK2 and multibacillary leprosy were stronger than the associations between these SNPs and paucibacillary leprosy. CONCLUSIONS: Variants of genes in the NOD2-mediated signaling pathway (which regulates the innate immune response) are associated with susceptibility to infection with M. leprae
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Carboxyamidotriazole reduces programmed cell death 1 expression by inhibiting NFAT2 nuclear transport in murine CD8+T cells
Objective To study the effect of carboxyamidotriazole (CAI) on CD8+T cells, and to explore the critical mechanism of CAI in reinforcing cytotoxicity of activated T cells. Methods CD8+T cells of mouse were isolated by immunomagnetic beads and divided into control group, CAI group, ZK756326 (Ca2+ activator) group and CAI+ZK756326 group. Flow cytometry was used to detect the level of intracellular free calcium ions in CD8+T cells; Enzyme-linked immunosorbent assay was used to detect the expression of intracellular calcineurin (CaN); Immunoflu- orescence staining was used to detect NFAT2 nuclear transportation; Chromatin immunoprecipitation-qPCR was used to detect the expression of PD-1 regulated by NFAT2. Mice spleen cytotoxic T lymphocytes (CTLs) were isolated and examined for the expression of PD-1 in CD8+T cells by flow cytometry. Results Intracellular Ca2+ concentration in CD8+T cells significantly decreased in the CAI group (P<0.001), while intracellular Ca2+ concentration increased in the CAI+ZK756326 group(P<0.01); CAI significantly decreased the content of calcineurin phosphatase in CD8+T cells (P<0.001);CAI significantly inhibited NFAT2 nuclear transportation (P<0.001) and significantly inhibited PD-1 transcription process depend on NFAT2 (P<0.001); CAI significantly reduced the proportion of PD-1+CD8+T cells in mice spleen CTLs cells (P<0.001). Conclusions CAI inhibits NFAT2 nuclear translocation by decreasing the level of calcium ions in the CD8+ T cells and inhibiting the expression of calcineurin, thereby reducing the expression of PD-1 in CD8+ T cells, which facilitated immunotherapy intervention
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