283 research outputs found

    Protein kinase Cδ and c-Abl kinase are required for transforming growth factor β induction of endothelial-mesenchymal transition in vitro.

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    OBJECTIVE: The origin of the mesenchymal cells responsible for the intimal fibrosis in systemic sclerosis (SSc) has not been fully identified. The present study was undertaken to investigate whether subendothelial mesenchymal cells may emerge through transdifferentiation of endothelial cells (ECs) into myofibroblasts via endothelial-mesenchymal transition (EndoMT) in vitro and to explore the signaling pathways involved in this process. METHODS: Primary mouse pulmonary ECs isolated by immunomagnetic methods with sequential anti-CD34 and anti-CD102 antibody selection were cultured in monolayers. Cell morphology and diacetylated low-density lipoprotein uptake assays confirmed their EC characteristics. The induction of EndoMT was assessed by determination of α-smooth muscle actin (α-SMA), type I collagen, and VE-cadherin expression, and the expression of the transcriptional repressor Snail-1 was analyzed. The signaling pathways involved were examined using small-molecule kinase inhibitors and RNA interference. RESULTS: Transforming growth factor β1 (TGFβ1) induced α-SMA and type I collagen expression and inhibited VE-cadherin. These effects were mediated by a marked increase in Snail-1 expression and were abolished by treatment with either the c-Abl tyrosine kinase inhibitor imatinib mesylate or the protein kinase Cδ (PKCδ) inhibitor rottlerin. The inhibitory effects of imatinib mesylate and rottlerin were mediated by inhibition of phosphorylation of glycogen synthase kinase 3β at residue Ser(9). These observations were confirmed in experiments using small interfering RNA specific for c-Abl and PKCδ. CONCLUSION: These results indicate that c-Abl and PKCδ are crucial for TGFβ-induced EndoMT and that imatinib mesylate and rottlerin or similar kinase inhibitor molecules may be effective therapeutic agents for SSc and other fibroproliferative vasculopathies in which EndoMT plays a pathogenetic role

    Contrast-Phys+: Unsupervised and Weakly-supervised Video-based Remote Physiological Measurement via Spatiotemporal Contrast

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    Video-based remote physiological measurement utilizes facial videos to measure the blood volume change signal, which is also called remote photoplethysmography (rPPG). Supervised methods for rPPG measurements have been shown to achieve good performance. However, the drawback of these methods is that they require facial videos with ground truth (GT) physiological signals, which are often costly and difficult to obtain. In this paper, we propose Contrast-Phys+, a method that can be trained in both unsupervised and weakly-supervised settings. We employ a 3DCNN model to generate multiple spatiotemporal rPPG signals and incorporate prior knowledge of rPPG into a contrastive loss function. We further incorporate the GT signals into contrastive learning to adapt to partial or misaligned labels. The contrastive loss encourages rPPG/GT signals from the same video to be grouped together, while pushing those from different videos apart. We evaluate our methods on five publicly available datasets that include both RGB and Near-infrared videos. Contrast-Phys+ outperforms the state-of-the-art supervised methods, even when using partially available or misaligned GT signals, or no labels at all. Additionally, we highlight the advantages of our methods in terms of computational efficiency, noise robustness, and generalization

    Stimulation of Transforming Growth Factor-β1-Induced Endothelial-To-Mesenchymal Transition and Tissue Fibrosis by Endothelin-1 (ET-1): A Novel Profibrotic Effect of ET-1.

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    TGF-β-induced endothelial-to-mesenchymal transition (EndoMT) is a newly recognized source of profibrotic activated myofibroblasts and has been suggested to play a role in the pathogenesis of various fibrotic processes. Endothelin-1 (ET-1) has been implicated in the development of tissue fibrosis but its participation in TGF-β-induced EndoMT has not been studied. Here we evaluated the role of ET-1 on TGF-β1-induced EndoMT in immunopurified CD31+/CD102+ murine lung microvascular endothelial cells. The expression levels of α-smooth muscle actin (α-SMA), of relevant profibrotic genes, and of various transcription factors involved in the EndoMT process were assessed employing quantitative RT-PCR, immunofluorescence histology and Western blot analysis. TGF-β1 caused potent induction of EndoMT whereas ET-1 alone had a minimal effect. However, ET-1 potentiated TGF-β1-induced EndoMT and TGF-β1-stimulated expression of mesenchymal cell specific and profibrotic genes and proteins. ET-1 also induced expression of the TGF-β receptor 1 and 2 genes, suggesting a plausible autocrine mechanism to potentiate TGF-β-mediated EndoMT and fibrosis. Stimulation of TGF-β1-induced skin and lung fibrosis by ET-1 was confirmed in vivo in an animal model of TGF-β1-induced tissue fibrosis. These results suggest a novel role for ET-1 in the establishment and progression of tissue fibrosis

    Energy-resolved Photoconductivity Mapping in a Monolayer-bilayer WSe2 Lateral Heterostructure

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    Vertical and lateral heterostructures of van der Waals materials provide tremendous flexibility for band structure engineering. Since electronic bands are sensitively affected by defects, strain, and interlayer coupling, the edge and heterojunction of these two-dimensional (2D) systems may exhibit novel physical properties, which can be fully revealed only by spatially resolved probes. Here, we report the spatial mapping of photoconductivity in a monolayer-bilayer WSe2 lateral heterostructure under multiple excitation lasers. As the photon energy increases, the light-induced conductivity detected by microwave impedance microscopy first appears along the hetero-interface and bilayer edge, then along the monolayer edge, inside the bilayer area, and finally in the interior of the monolayer region. The sequential emergence of mobile carriers in different sections of the sample is consistent with the theoretical calculation of local energy gaps. Quantitative analysis of the microscopy and transport data also reveals the linear dependence of photoconductivity on the laser intensity and the influence of interlayer coupling on carrier recombination. Combining theoretical modeling, atomic scale imaging, mesoscale impedance microscopy, and device-level characterization, our work suggests an exciting perspective to control the intrinsic band-gap variation in 2D heterostructures down to the few-nanometer regime.Comment: 18 pages, 5 figures; Nano Lett., Just Accepted Manuscrip

    ANALYSIS OF LATERAL DISPLACEMENT AND EVALUATION OF TREATMENT MEASURES OF CURVED BEAM: A CASE STUDY

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    The curved beam bridge exhibits lateral displacement during construction and operation. Taking a curved beam bridge as an example, the status of lateral displacement of the bridge is investigated in detail in this paper. To understand the mechanism of the curved beam lateral displacement, further to determine the curved beam lateral displacement under temperature effect, using ANSYS software to establish solid element model of the curved beam, steady state thermal analysis method is applied to analyze temperature field. Based on the analysis, the lateral displacement under temperature effect is analyzed. Then in order to further explain the lateral displacement mechanism, to discuss the frictional force causing the residual deformation of the rubber bearing to make the lateral displacement of the curved beam, the mechanical mechanism of curved beam under temperature effect is approximately analyzed. On the basis of clarifying the mechanism of lateral displacement, the paper puts forward the reinforcement measures for the curved beam bridge. In order to verify the treatment effect, long-term displacement monitoring is performed on the bridge. Numerical studies and monitoring data show that temperature is the main factor that causes the lateral displacement. Monitoring data over the past year shows that the displacement of the bearing is less than the value of allowable displacement after the reinforcement measures are adopted, and the bridge is in a safe state
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