24 research outputs found

    Effect of narrow groove MAG welding oscillation parameters on weld formation

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    In order to solve the problem of narrow groove wall fusion, improving the weld formation, the welding test of different oscillation width and frequency is carried out by adopting the narrow high-speed swing MAG welding torch. On the basis of measuring the macro metallographic to determine the weld cross section size, the curve fitting of the variation trend of the weld section size with the swing width and the swing frequency is carried out. The effect of the high speed swing arc narrow groove welding MAG parameters on weld formation is studied. The results show that increasing the swing width or frequency can reduce the weld penetration and increase lateral wall penetration; when the swinging width makes side spacing greater than -05 mm and less than 1 mm, good weld forming will be gained; when the oscillation frequency increases to more than 5 Hz, weld finger penetration can be eliminated, but when it is above 9 Hz, increasing the swing frequency cannot cause obvious change of the dimension of weld. The effects of these oscillating parameters on weld formation can provide guidance for the selection of welding parameters

    Research status of seam tracking methods for orbital pipe welding robots

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    This paper first outlines the worldwide oil and gas pipeline laying situation by 2013 and industrial applications, the working characteristics and advantages of orbital pipe welding robots using the gas metal arc metal(GMAW). Then the classifications of commonly used welding seam tracking sensors are comprehensively introduced. The sensor working principles, advantages and disadvantages and the application situation in pipeline welding are analysed in details. The studies show that arc sensors and visual sensors have many advantages such as good real-time characteristic, informativeness and high tracking precision, and are most widely used in pipeline welding. Using single sensor in different process can limit the tracking precision easily, but a system with multiple sensors will greatly improve the tracking precision in oil and gas pipeline welding. A system using visual sensor and arc sensor has been used in the gas field pipeline welding in Japan and a good effect has been achieved. Finally the conclusion is drawn that suitable seam tracking sensor should be chosen according to the process features and methods, and using a variety of sensors can improve the welding seam tracking precision, which will become the focus of future researches

    Upregulation of LncDQ is Associated with Poor Prognosis and Promotes Tumor Progression via Epigenetic Regulation of the EMT Pathway in HCC

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    Background/Aims: Long noncoding RNAs (lncRNAs) are key regulators of cancer initiation and progression. In this study, we investigated the clinical value and functional role of LncRNA DQ786243 (LncDQ) in the pathogenesis of hepatocellular carcinoma (HCC). Methods: To investigate the expression level of LncDQ in HCC, we performed quantitative real-time PCR using total RNA extracted from HCC tumor tissues and their matched non-neoplastic counterparts, as well as from the serum of HCC patients and healthy volunteers. The correlation of LncDQ expression with clinicopathologic features and prognosis was analyzed. The functional role of LncDQ in cell proliferation, migration, and invasion were evaluated by MTT cell viability, wound healing, and transwell assays in vitro and in vivo. RNA immunoprecipitation and chromatin immunoprecipitation assays were performed to analyze the potential mechanism of LncDQ in HCC cells. Results: LncDQ was upregulated in both HCC tissue samples and serum and was correlated with low survival rate and adverse clinical pathological characteristics. Multivariate analysis demonstrated that LncDQ expression was an independent prognostic factor for HCC. The area under the receiver operating characteristic curve was 0.804 with a sensitivity of 0.72 and a specificity of 0.8. Knockdown of LncDQ induced inhibition of cell proliferation, migration, and invasion in vitro and in vivo. Mechanistically, LncDQ regulated the epithelial–mesenchymal transition pathway by interacting with EZH2, to epigenetically repress the expression of E-cadherin in HCC cells. Conclusions: Taken together, the results of our study indicate that LncDQ plays a critical role in HCC progression, and may serve as a potential diagnostic and prognostic biomarker for HCC

    UBQLN1 deficiency leads to DNA replication stress.

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    (A) RPA1 foci increased in UBQLN1 depleted VA13 cells. Cells were transfected with indicated siRNAs for 72 h and IF was performed. Scale bars, 5μm. (B-C) Quantification of (A). Cells contain more than one RPA1 foci were calculated. Total (B) or telomere localized (C) RPA1 foci were counted respectively. All values are means ± SEM of more than three independent experiments (* P (TIF)</p

    UBQLN1 is involved in DNA replication.

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    (A) RPA1 foci increased in UBQLN1 depleted HeLa cells. Cells were transfected with indicated siRNAs for 72 h and IF was performed. Scale bars, 5μm. (B-C) Quantification of A. Cells contain more than one RPA1 foci were calculated. Total (B) or telomere localized (C) RPA1 foci were counted respectively. (D-F) Experiments in A-C were repeated in U2OS cells. (G) Protein levels in UBQLN1 knockdown cells. Immunoblot analysis of indicated proteins in HeLa cells 72 h after siRNA transfection (n = 3). (H) DNA fiber assay in UBQLN1 knockdown cells. HeLa cells were transfected with indicated siRNAs for 72 h. Cells were labeled with CldU for 30 min and subsequently with IdU for 20 min during the last 50 minutes, then the DNA fiber assay was performed. (I) Quantification of H. The length of IdU labeled DNA (green) was calculated (n ≥ 500 DNA). All values are means ± SEM of more than three independent experiments (* P<0.05, ** P<0.01, *** P<0.001, ****P<0.0001).</p
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