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  • Hindawi Limited  (4)
  • 1
    Online Resource
    Online Resource
    Hindawi Limited ; 2021
    In:  Mathematical Problems in Engineering Vol. 2021 ( 2021-1-21), p. 1-11
    In: Mathematical Problems in Engineering, Hindawi Limited, Vol. 2021 ( 2021-1-21), p. 1-11
    Abstract: Deformation mechanism in the core rockfill dams with heavy load and high-stress level is difficult to predict and control, which is one of the key problems to be solved in the dam operation safety management and control. Aiming at the large error problems obtained by the parameter-based functional models (regression model, grey theory model, etc.) in the deformation prediction of the core rockfill dams, a fractal prediction method and its technical process by combining the variable dimension fractal dimension and the "metabolism" of prediction data are proposed through analyzing the fractal adaptability and deformation characteristics of original monitoring data based on the resealed-range (R/S) method and fractal dimension theory. It effectively solves the error in the process of constant dimension fractal accumulation and transformation greatly in dam deformation prediction and provides a new way for dam safety monitoring deformation prediction and early warning. The trend analysis of deformation monitoring data of the Pubugou core rockfill dam and the deformation prediction show that the fractal prediction information of dam deformation has a good corresponding relationship with its physical causes, which is in line with the actual deformation trend and operation state of the dam. Compared with the traditional stepwise regression method, the prediction results obtained by the proposed method in this paper are of high accuracy, implying that the improved fractal prediction of dam deformation is effective and the Hurst fractal index is applicable in the evaluation of the dam deformation trend.
    Type of Medium: Online Resource
    ISSN: 1563-5147 , 1024-123X
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2021
    detail.hit.zdb_id: 2014442-8
    SSG: 11
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  • 2
    Online Resource
    Online Resource
    Hindawi Limited ; 2013
    In:  Advances in Materials Science and Engineering Vol. 2013 ( 2013), p. 1-9
    In: Advances in Materials Science and Engineering, Hindawi Limited, Vol. 2013 ( 2013), p. 1-9
    Abstract: The tube numerical control (NC) bending process is a much complex physical process with multifactors coupling interactive effects. The mandrel is the key to improve forming quality and to enhance forming limit. In this study, based on the platform of ABAQUS/Explicit, a 3D elastic-plastic finite element model of NC bending process of 2169 (0Cr21Ni6Mn9N) stainless steel tube was established, key technological problems were solved, and its reliability was validated. Then, simulation and analysis of the processes were carried out, and the influence laws of mandrel types and mandrel parameters on cross-section quality were obtained. The results show that the wall thinning or cross section deformation is serious at the middle part and small in the vicinity of the bending plane or initial bending plane; the wall thinning degree increases or the cross section deformation degree decreases with the increase of mandrel diameter or mandrel extension length; the effect of bulb mandrel on the cross section quality is more significant than that of cylinder mandrel. And the reasonable mandrel types and mandrel parameters are chosen for the 2169 high-pressure hydraulic tube with small diameter. The results may lead to better understanding of mandrel role in the improvement of forming quality and forming limit in the NC bending process.
    Type of Medium: Online Resource
    ISSN: 1687-8434 , 1687-8442
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2013
    detail.hit.zdb_id: 2501025-6
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  • 3
    In: Oxidative Medicine and Cellular Longevity, Hindawi Limited, Vol. 2022 ( 2022-3-10), p. 1-30
    Abstract: Postoperative peritoneal adhesion (PPA) is a major clinical complication after open surgery or laparoscopic procedure. Ligustrazine is the active ingredient extracted from the natural herb Ligusticum chuanxiong Hort, which has promising antiadhesion properties. This study is aimed at revealing the underlying mechanisms of ligustrazine in preventing PPA at molecular and cellular levels. Both rat primary peritoneal mesothelial cells (PMCs) and human PMCs were used for analysis in vitro. Several molecular biological techniques were applied to uncover the potential mechanisms of ligustrazine in preventing PPA. And molecular docking and site-directed mutagenesis assay were used to predict the binding sites of ligustrazine with PPARγ. The bioinformatics analysis was further applied to identify the key pathway in the pathogenesis of PPA. Besides, PPA rodent models were prepared and developed to evaluate the novel ligustrazine nanoparticles in vivo. Ligustrazine could significantly suppress hypoxia-induced PMC functions, such as restricting the production of profibrotic cytokines, inhibiting the expression of migration and adhesion-associated molecules, repressing the expression of cytoskeleton proteins, restricting hypoxia-induced PMCs to obtain myofibroblast-like phenotypes, and reversing ECM remodeling and EMT phenotype transitions by activating PPARγ. The antagonist GW9662 of PPARγ could restore the inhibitory effects of ligustrazine on hypoxia-induced PMC functions. The inhibitor KC7F2 of HIF-1α could repress hypoxia-induced PMC functions, and ligustrazine could downregulate the expression of HIF-1α, which could be reversed by GW9662. And the expression of HIF-1α inhibited by ligustrazine was dramatically reversed after transfection with si-SMRT. The results showed that the benefit of ligustrazine on PMC functions is contributed to the activation of PPARγ on the transrepression of HIF-1α in an SMRT-dependent manner. Molecular docking and site-directed mutagenesis tests uncovered that ligustrazine bound directly to PPARγ, and Val 339/Ile 341 residue was critical for the binding of PPARγ to ligustrazine. Besides, we discovered a novel nanoparticle agent with sustained release behavior, drug delivery efficiency, and good tissue penetration in PPA rodent models. Our study unravels a novel mechanism of ligustrazine in preventing PPA. The findings indicated that ligustrazine is a potential strategy for PPA formation and ligustrazine nanoparticles are promising agents for preclinical application.
    Type of Medium: Online Resource
    ISSN: 1942-0994 , 1942-0900
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2022
    detail.hit.zdb_id: 2455981-7
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  • 4
    In: BioMed Research International, Hindawi Limited, Vol. 2014 ( 2014), p. 1-7
    Abstract: Previous studies reported discrepant white matter diffusivity in mild traumatic brain injury (mTBI) on the base of Glasgow Coma Scale, which are unreliable for some TBI severity indicators and the frequency of missing documentation in the medical record. In the present study, we adopted the Mayo classification system for TBI severity. In this system, the mTBI is also divided into two groups as “probable and symptomatic” TBI. We aimed to investigate altered microstructural integrity in symptomatic acute TBI ( 〈 1 week) by using tract-based spatial statics (TBSS) approach. A total of 12 patients and 13 healthy volunteers were involved and underwent MRI scans including conventional scan, and SWI and DTI. All the patients had no visible lesions by using conventional and SWI neuroimaging techniques, while showing widespread declines in the fractional anisotropy (FA) of gray matter and white matter throughout the TBSS skeleton, particularly in the limbic-subcortical structures. By contrast, symptomatic TBI patients showed no significant enhanced changes in FA compared to the healthy controls. A better understanding of the acute changes occurring following symptomatic TBI may increase our understanding of neuroplasticity and continuing degenerative change, which, in turn, may facilitate advances in management and intervention.
    Type of Medium: Online Resource
    ISSN: 2314-6133 , 2314-6141
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2014
    detail.hit.zdb_id: 2698540-8
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