48 research outputs found

    T Cell–specific Ablation of Fas Leads to Fas Ligand–mediated Lymphocyte Depletion and Inflammatory Pulmonary Fibrosis

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    To study the role of Fas–Fas ligand (FasL) interaction-mediated apoptosis in lymphocyte homeostasis, we generated a mutant fas allele allowing conditional inactivation of the fas gene through Cre-mediated recombination. Experiments in which Fas was ablated in T cells, B cells, T and B cells, or in a more generalized manner demonstrated that the development of lymphoproliferative disease as seen in Fas-deficient mice requires Fas ablation in lymphoid and nonlymphoid tissues. Selective inactivation of Fas in T cells led to a severe lymphopenia over time, accompanied by up-regulation of FasL on activated T cells and apoptosis of peripheral lymphocytes. In addition, the mutant animals developed a fatal wasting syndrome caused by massive leukocyte infiltration in the lungs together with increased inflammatory cytokine production and pulmonary fibrosis. Inhibition of Fas–FasL interaction in vivo completely prevented the loss of lymphocytes and initial lymphocyte infiltration in the lungs. Thus, FasL-mediated interaction of activated, Fas-deficient T cells with Fas-expressing cells in their environment leads to break down of lymphocyte homeostasis and development of a lung disease strikingly resembling idiopathic pulmonary fibrosis in humans, a common and severe disease for which the mutant mice may serve as a first animal model

    Mule Regulates the Intestinal Stem Cell Niche via the Wnt Pathway and Targets EphB3 for Proteasomal and Lysosomal Degradation

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    The E3 ubiquitin ligase Mule is often overexpressed in human colorectal cancers, but its role in gut tumorigenesis is unknown. Here, we show in vivo that Mule controls murine intestinal stem and progenitor cell proliferation by modulating Wnt signaling via c-Myc. Mule also regulates protein levels of the receptor tyrosine kinase EphB3 by targeting it for proteasomal and lysosomal degradation. In the intestine, EphB/ephrinB interactions position cells along the crypt-villus axis and compartmentalize incipient colorectal tumors. Our study thus unveils an important new avenue by which Mule acts as an intestinal tumor suppressor by regulation of the intestinal stem cell niche

    Solutions of the Two-Dimensional Hubbard Model: Benchmarks and Results from a Wide Range of Numerical Algorithms

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    Numerical results for ground-state and excited-state properties (energies, double occupancies, and Matsubara-axis self-energies) of the single-orbital Hubbard model on a two-dimensional square lattice are presented, in order to provide an assessment of our ability to compute accurate results in the thermodynamic limit. Many methods are employed, including auxiliary-field quantum Monte Carlo, bare and bold-line diagrammatic Monte Carlo, method of dual fermions, density matrix embedding theory, density matrix renormalization group, dynamical cluster approximation, diffusion Monte Carlo within a fixed-node approximation, unrestricted coupled cluster theory, and multireference projected Hartree-Fock methods. Comparison of results obtained by different methods allows for the identification of uncertainties and systematic errors. The importance of extrapolation to converged thermodynamic-limit values is emphasized. Cases where agreement between different methods is obtained establish benchmark results that may be useful in the validation of new approaches and the improvement of existing methods

    K48-linked KLF4 ubiquitination by E3 ligase Mule controls T-cell proliferation and cell cycle progression.

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    peer reviewedT-cell proliferation is regulated by ubiquitination but the underlying molecular mechanism remains obscure. Here we report that Lys-48-linked ubiquitination of the transcription factor KLF4 mediated by the E3 ligase Mule promotes T-cell entry into S phase. Mule is elevated in T cells upon TCR engagement, and Mule deficiency in T cells blocks proliferation because KLF4 accumulates and drives upregulation of its transcriptional targets E2F2 and the cyclin-dependent kinase inhibitors p21 and p27. T-cell-specific Mule knockout (TMKO) mice develop exacerbated experimental autoimmune encephalomyelitis (EAE), show impaired generation of antigen-specific CD8+ T cells with reduced cytokine production, and fail to clear LCMV infections. Thus, Mule-mediated ubiquitination of the novel substrate KLF4 regulates T-cell proliferation, autoimmunity and antiviral immune responses in vivo

    Foreign-Object Detection in High-Voltage Transmission Line Based on Improved YOLOv8m

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    The safe operation of high-voltage transmission lines ensures the power grid’s security. Various foreign objects attached to the transmission lines, such as balloons, kites and nesting birds, can significantly affect the safe and stable operation of high-voltage transmission lines. With the advancement of computer vision technology, periodic automatic inspection of foreign objects is efficient and necessary. Existing detection methods have low accuracy because foreign objects attached to the transmission lines are complex, including occlusions, diverse object types, significant scale variations, and complex backgrounds. In response to the practical needs of the Yunnan Branch of China Southern Power Grid Co., Ltd., this paper proposes an improved YOLOv8m-based model for detecting foreign objects on transmission lines. Experiments are conducted on a dataset collected from Yunnan Power Grid. The proposed model enhances the original YOLOv8m by incorporating a Global Attention Module (GAM) into the backbone to focus on occluded foreign objects, replacing the SPPF module with the SPPCSPC module to augment the model’s multiscale feature extraction capability, and introducing the Focal-EIoU loss function to address the issue of high- and low-quality sample imbalances. These improvements accelerate model convergence and enhance detection accuracy. The experimental results demonstrate that our proposed model achieves a 2.7% increase in mAP_0.5, a 4% increase in mAP_0.5:0.95, and a 6% increase in recall
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