304 research outputs found
Lattice QCD calculation of scattering length
We study s-wave pion-pion () scattering length in lattice QCD for
pion masses ranging from 330 MeV to 466 MeV. In the "Asqtad" improved staggered
fermion formulation, we calculate the four-point functions for isospin
I=0 and 2 channels, and use chiral perturbation theory at next-to-leading order
to extrapolate our simulation results. Extrapolating to the physical pion mass
gives the scattering lengths as and for isospin I=2 and 0 channels, respectively. Our lattice
simulation for scattering length in the I=0 channel is an exploratory
study, where we include the disconnected contribution, and our preliminary
result is near to its experimental value. These simulations are performed with
MILC 2+1 flavor gauge configurations at lattice spacing fm.Comment: Remove some typo
Half-Quantized Hall Effect at the Parity-Invariant Fermi Surface
Condensed matter realization of a single Dirac cone of fermions in two
dimensions is a long-standing issue. Here we report the discovery of a single
gapless Dirac cone of half-quantized Hall conductance in a magnetically-doped
topological insulator heterostructure. It demonstrates that the Hall
conductance is half-quantized in the unit e^{2}/h when the parity symmetry is
invariant near the Fermi surface. The gapless Dirac point is stable and
protected by the local parity symmetry and the topologically nontrivial band
structure of the topological insulator. The one-half Hall conductance observed
in a recent experiment [Mogi et al, Nat. Phys. 18, 390 (2022)] is attributed to
the existence of the gapless Dirac cone. The results suggest a condensed matter
realization of a topological phase with a one-half topological invariant.Comment: 6 pages with 4 figure
MicroRNA-1 acts as a tumor suppressor microRNA by inhibiting angiogenesis-related growth factors in human gastric cancer
Background
We recently reported that miR-1 was one of the most significantly downregulated microRNAs in gastric cancer (GC) patients from The Cancer Genome Atlas microRNA sequencing data. Here we aim to elucidate the role of miR-1 in gastric carcinogenesis.
Methods
We measured miR-1 expression in human GC cell lines and 90 paired primary GC samples, and analyzed the association of its status with clinicopathological features. The effect of miR-1 on GC cells was evaluated by proliferation and migration assay. To identify the target genes of miR-1, bioinformatic analysis and protein array analysis were performed. Moreover, the regulation mechanism of miR-1 with regard to these predicted targets was investigated by quantitative PCR (qPCR), Western blot, ELISA, and endothelial cell tube formation. The putative binding site of miR-1 on target genes was assessed by a reporter assay.
Results
Expression of miR-1 was obviously decreased in GC cell lines and primary tissues. Patients with low miR-1 expression had significantly shorter overall survival compared with those with high miR-1 expression (P = 0.0027). Overexpression of miR-1 in GC cells inhibited proliferation, migration, and tube formation of endothelial cells by suppressing expression of vascular endothelial growth factor A (VEGF-A) and endothelin 1 (EDN1). Conversely, inhibition of miR-1 with use of antago-miR-1 caused an increase in expression of VEGF-A and EDN1 in nonmalignant GC cells or low-malignancy GC cells.
Conclusions
MiR-1 acts as a tumor suppressor by inhibiting angiogenesis-related growth factors in human gastric cancer. Downregulated miR-1 not only promotes cellular proliferation and migration of GC cells, but may activates proangiogenesis signaling and stimulates the proliferation and migration of endothelial cells, indicating the possibility of new strategies for GC therapy
Automatic and Rapid Discrimination of Cotton Genotypes by Near Infrared Spectroscopy and Chemometrics
This paper reports the application of near infrared (NIR) spectroscopy and pattern recognition methods to rapid and automatic discrimination of the genotypes (parent, transgenic, and parent-transgenic hybrid) of cotton plants. Diffuse reflectance NIR spectra of representative cotton seeds (n = 120) and leaves (n = 123) were measured in the range of 4000ā12000ācmā1. A practical problem when developing classification models is the degradation and even breakdown of models caused by outliers. Considering the high-dimensional nature and uncertainty of potential spectral outliers, robust principal component analysis (rPCA) was applied to each separate sample group to detect and exclude outliers. The influence of different data preprocessing methods on model prediction performance was also investigated. The results demonstrate that rPCA can effectively detect outliers and maintain the efficiency of discriminant analysis. Moreover, the classification accuracy can be significantly improved by second-order derivative and standard normal variate (SNV). The best partial least squares discriminant analysis (PLSDA) models obtained total classification accuracy of 100% and 97.6% for seeds and leaves, respectively
Cognitive decline and white matter changes in mesial temporal lobe epilepsy
Noninvasive imaging plays a pivotal role in assessing the brain structural and functional changes in presurgical mesial temporal lobe epilepsy (MTLE) patients. Our goal was to study the relationship between the changes of cerebral white matter (WM) and cognitive functions in MTLE patients.Voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) MRI were performed on 24 right-handed MTLE patients (12 with left MTLE and 12 with right MTLE) and 12 matching healthy controls. Gray matter (GM), WM, and whole brain (WB) volumes were measured with VBM while fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were measured with TBSS. All patients and controls also underwent Montreal Cognitive Assessment (MoCA) before MRI.WM volume and the ratio of WM volume versus WB volume were significantly lower in MTLE patients compared with controls. WM volume in MTLE patients had a positive correlation with MoCA score (rā=ā0.71, Pā<ā.001) and a negative correlation with the duration of epilepsy (rā=ā-0.693, Pā<ā.001). Volumetric differences were mainly located in the corpus callosum, uncinate fasciculus, inferior longitudinal fasciculus, and superior longitudinal fasciculus. FA of both left MTLE and right MTLE groups was significantly decreased, while MD, AD, and RD were significantly increased. Most left MTLE patients showed bilateral WM fiber tract changes versus ipsilateral changes for right MTLE patients.Changes in DTI parameters and WM volume were found in MTLE patients and more ipsilateral changes were seen with right-sided MTLE. Cognitive changes of MTLE patients were found to be correlated with the changes in WM structure. These findings not only provide useful information for lateralization of the seizure focus but can also be used to explain functional connectivity disorders which may be an important physiological basis for cognitive changes in patients with MTLE
Development and application of software system for dynamic analysis of grain condition cloud map
Based on the theory of grain storage ecosystem, multi-field coupling and ventilation window, the dynamic analysis software of grain condition cloud map is researched and developed by WU model,sinusoidal model of grain temperature change, heat and mass transfer model and related empirical model.By drawing visual dynamic cloud maps of grain condition, combining with the warehouse types, grain storage characteristics and regional environment, the state and change of grain storage can be analyzed and predicted,then the quantity and quality can be distinguished.In addition, the software system has been applied and improved in the national warehouse inventory in 2018 and 2019.It provides effective technical support and tool services for the realization of the whole process of grain storage quantity and quality safety management
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Sulfated tyrosines 27 and 29 in the N-terminus of human CXCR3 participate in binding native IP-10
Aim: Human CXCR3, a seven-transmembrane segment (7TMS), is predominantly expressed in Th1-mediated responses. Interferon-Ī³-inducible protein 10 (IP-10) is an important ligand for CXCR3. Their interaction is pivotal for leukocyte migration and activation. Tyrosine sulfation in 7TMS is a posttranslational modification that contributes substantially to ligand binding. We aimed to study the role of tyrosine sulfation of CXCR3 in the protein's binding to IP-10. Methods: Plasmids encoding CXCR3 and its mutants were prepared by PCR and site-directed mutagenesis. HEK 293T cells were transfected with plasmids encoding CXCR3 or its variants using calcium phosphate. Transfected cells were labeled with [35S]-cysteine and methionine or [35S]-Na2SO3 and then analyzed by immunoprecipitation to measure sulfation. Experiments with 125I-labeled IP-10 were carried out to evaluate the affinity of CXCR3 for its ligand. Calcium influx assays were used to measure intercellular signal transduction. Results: Our data show that sulfate moieties are added to tyrosines 27 and 29 of CXCR3. Mutation of these two tyrosines to phenylalanines substantially decreases binding of CXCR3 to IP-10 and appears to eliminate the associated signal transduction. Tyrosine sulfation of CXCR3 is enhanced by tyrosyl protein sulfotransferases (TPSTs), and it is weakened by shRNA constructs. The binding ability of CXCR3 to IP-10 is increased by TPSTs and decreased by shRNAs. Conclusions: This study identifies two sulfated tyrosines in the N-terminus of CXCR3 as part of the binding site for IP-10, and it underscores the fact that tyrosine sulfation in the N-termini of 7TMS receptors is functionally important for ligand interactions. Our study suggests a molecular target for inhibiting this ligand-receptor interaction
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