54 research outputs found

    Credit Risk Assessment of Banks' Loan Enterprise Customer Based on State-Constraint

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    Commercial banks are facing increasingly complex enterprise loan customers and businesses. It is important for banks' enterprise loan business to efficiently assess credit risks. Our study builds an enterprise credit risk assessment model based on the state and constraint of bank and customer, and get empirical researches with RF, SVM and DT algorithms. The results show that our model has excellent performance with accuracy 99 % and great characteristic importance in the evaluation of enterprise credit risk. The study can provide important decision-making reference for bank loan business and enrich the theoretical system of bank credit risk research

    3D-U-SAM Network For Few-shot Tooth Segmentation in CBCT Images

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    Accurate representation of tooth position is extremely important in treatment. 3D dental image segmentation is a widely used method, however labelled 3D dental datasets are a scarce resource, leading to the problem of small samples that this task faces in many cases. To this end, we address this problem with a pretrained SAM and propose a novel 3D-U-SAM network for 3D dental image segmentation. Specifically, in order to solve the problem of using 2D pre-trained weights on 3D datasets, we adopted a convolution approximation method; in order to retain more details, we designed skip connections to fuse features at all levels with reference to U-Net. The effectiveness of the proposed method is demonstrated in ablation experiments, comparison experiments, and sample size experiments.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Self-compression of femtosecond pulses in normally dispersive media

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    Self-compression is a simple method to achieve ultrashort and ultraintense pulses. By solving a modified nonlinear Schrodinger equation considering the fifth-order susceptibility, it is found that self-compression appeared even in normally dispersive media owing to the negative fifth-order susceptibility inducing a mass of negative frequency chirp. Furthermore, negatively pre-chirped pulses help to achieve pulse self-compression at lower input peak intensity which will avoid the damage of media. The optimized-choosing of pre-chirp, input intensity and length of media are numerically analyzed. Proof-of-principle experiments successfully prove the above theoretical findings. It is expected that petawatt laser pulses with 25 fs/15 fs transform limited pulse duration can be self-compressed to about 10.7 fs/8.8 fs in normally dispersive media such as fused silica glass plates.Comment: 24 pages, 8 figures, 1 tabl

    Myogenic progenitors contribute to open but not closed fracture repair

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    <p>Abstract</p> <p>Background</p> <p>Bone repair is dependent on the presence of osteocompetent progenitors that are able to differentiate and generate new bone. Muscle is found in close association with orthopaedic injury, however its capacity to make a cellular contribution to bone repair remains ambiguous. We hypothesized that myogenic cells of the MyoD-lineage are able to contribute to bone repair.</p> <p>Methods</p> <p>We employed a <it>MyoD</it>-Cre<sup>+</sup>:Z/AP<sup>+ </sup>conditional reporter mouse in which all cells of the MyoD-lineage are permanently labeled with a <it>human alkaline phosphatase (hAP) </it>reporter. We tracked the contribution of MyoD-lineage cells in mouse models of tibial bone healing.</p> <p>Results</p> <p>In the absence of musculoskeletal trauma, MyoD-expressing cells are limited to skeletal muscle and the presence of reporter-positive cells in non-muscle tissues is negligible. In a closed tibial fracture model, there was no significant contribution of hAP<sup>+ </sup>cells to the healing callus. In contrast, open tibial fractures featuring periosteal stripping and muscle fenestration had up to 50% of hAP<sup>+ </sup>cells detected in the open fracture callus. At early stages of repair, many hAP<sup>+ </sup>cells exhibited a chondrocyte morphology, with lesser numbers of osteoblast-like hAP<sup>+ </sup>cells present at the later stages. Serial sections stained for hAP and type II and type I collagen showed that MyoD-lineage cells were surrounded by cartilaginous or bony matrix, suggestive of a functional role in the repair process. To exclude the prospect that osteoprogenitors spontaneously express MyoD during bone repair, we created a metaphyseal drill hole defect in the tibia. No hAP<sup>+ </sup>staining was observed in this model suggesting that the expression of MyoD is not a normal event for endogenous osteoprogenitors.</p> <p>Conclusions</p> <p>These data document for the first time that muscle cells can play a significant secondary role in bone repair and this knowledge may lead to important translational applications in orthopaedic surgery.</p> <p>Please see related article: <url>http://www.biomedcentral.com/1741-7015/9/136</url></p

    Myoblast sensitivity and fibroblast insensitivity to osteogenic conversion by BMP-2 correlates with the expression of Bmpr-1a

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    <p>Abstract</p> <p>Background</p> <p>Osteoblasts are considered to primarily arise from osseous progenitors within the periosteum or bone marrow. We have speculated that cells from local soft tissues may also take on an osteogenic phenotype. Myoblasts are known to adopt a bone gene program upon treatment with the osteogenic bone morphogenetic proteins (BMP-2,-4,-6,-7,-9), but their osteogenic capacity relative to other progenitor types is unclear. We further hypothesized that the sensitivity of cells to BMP-2 would correlate with BMP receptor expression.</p> <p>Methods</p> <p>We directly compared the BMP-2 sensitivity of myoblastic murine cell lines and primary cells with osteoprogenitors from osseous tissues and fibroblasts. Fibroblasts forced to undergo myogenic conversion by transduction with a MyoD-expressing lentiviral vector (LV-MyoD) were also examined. Outcome measures included alkaline phosphatase expression, matrix mineralization, and expression of osteogenic genes <it>(alkaline phosphatase, osteocalcin </it>and <it>bone morphogenetic protein receptor-1A) </it>as measured by quantitative PCR.</p> <p>Results</p> <p>BMP-2 induced a rapid and robust osteogenic response in myoblasts and osteoprogenitors, but not in fibroblasts. Myoblasts and osteoprogenitors grown in osteogenic media rapidly upregulated <it>Bmpr-1a </it>expression. Chronic BMP-2 treatment resulted in peak <it>Bmpr-1a </it>expression at day 6 before declining, suggestive of a negative feedback mechanism. In contrast, fibroblasts expressed low levels of <it>Bmpr-1a </it>that was only weakly up-regulated by BMP-2 treatment. Bioinformatics analysis confirmed the presence of myogenic responsive elements in the proximal promoter region of human and murine <it>BMPR-1A/Bmpr-1a</it>. Forced myogenic gene expression in fibroblasts was associated with a significant increase in <it>Bmpr-1a </it>expression and a synergistic increase in the osteogenic response to BMP-2.</p> <p>Conclusion</p> <p>These data demonstrate the osteogenic sensitivity of muscle progenitors and provide a mechanistic insight into the variable response of different cell lineages to BMP-2.</p

    Interplay of Nkx3.2, Sox9 and Pax3 Regulates Chondrogenic Differentiation of Muscle Progenitor Cells

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    Muscle satellite cells make up a stem cell population that is capable of differentiating into myocytes and contributing to muscle regeneration upon injury. In this work we investigate the mechanism by which these muscle progenitor cells adopt an alternative cell fate, the cartilage fate. We show that chick muscle satellite cells that normally would undergo myogenesis can be converted to express cartilage matrix proteins in vitro when cultured in chondrogenic medium containing TGFß3 or BMP2. In the meantime, the myogenic program is repressed, suggesting that muscle satellite cells have undergone chondrogenic differentiation. Furthermore, ectopic expression of the myogenic factor Pax3 prevents chondrogenesis in these cells, while chondrogenic factors Nkx3.2 and Sox9 act downstream of TGFß or BMP2 to promote this cell fate transition. We found that Nkx3.2 and Sox9 repress the activity of the Pax3 promoter and that Nkx3.2 acts as a transcriptional repressor in this process. Importantly, a reverse function mutant of Nkx3.2 blocks the ability of Sox9 to both inhibit myogenesis and induce chondrogenesis, suggesting that Nkx3.2 is required for Sox9 to promote chondrogenic differentiation in satellite cells. Finally, we found that in an in vivo mouse model of fracture healing where muscle progenitor cells were lineage-traced, Nkx3.2 and Sox9 are significantly upregulated while Pax3 is significantly downregulated in the muscle progenitor cells that give rise to chondrocytes during fracture repair. Thus our in vitro and in vivo analyses suggest that the balance of Pax3, Nkx3.2 and Sox9 may act as a molecular switch during the chondrogenic differentiation of muscle progenitor cells, which may be important for fracture healing

    Role of Endoplasmic Reticulum Stress, Autophagy, and Inflammation in Cardiovascular Disease

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    Cardiovascular diseases are a class of heart or blood vessels diseases, which are now considered to be the leading cause of death globally. A number of recent studies have reported key roles for inflammation in the progression of diseased vessels and systematic heart failure. In particular, endoplasmic reticulum (ER) stress, which is mechanistically implicated in inflammation and autophagy, has now been associated with pathophysiological states in the cardiovascular system. Autophagy has also been identified as an important process in the progression of multiple cardiovascular diseases such as in atherosclerosis plaque progression and ischemia and/or reperfusion. In light of the above, it has been proposed that a link between inflammation, autophagy, and ER stress may exist that contribute to diseases of the heart and its supporting vessels. This review highlights current knowledge on the cross talk between these three biological processes, and the potential of targeting this pathway as a therapeutic approach for cardiovascular disorders and its related diseases
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