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In the absence of experimental investigations on column members of underground structures, full‐scale column specimens were tested to explore the seismic behavior of shallow‐buried subway stations at various depths. The axial compression ratios of internal column specimens were set as 0.16, 0.33, and 0.40. Both hybrid simulations and quasi‐static tests were performed on the station columns. The hybrid simulations illustrated the drift demands of internal columns, while the load‐carrying capacity and deformation capacity were obtained from the quasi‐static tests. Hybrid simulations at low, moderate, and high‐intensity levels were conducted to study the seismic responses of shallow‐buried rectangular stations. The hybrid simulations suggest that the most severe damage occurred in the station when the axial compression ratio of the tested column reached 0.40. Central columns suffered severe stiffness deterioration under high‐level earthquake excitation, especially in stations at greater depths. Meanwhile, the quasi‐static test results indicate that the ultimate load of the central columns increases with increasing axial compression, but this leads to a significant decrease in the ductility of columns. Besides, the sectional analysis results show that the central columns are prone to tension‐controlled failure, and the safety margin for flexural response deteriorates with an increasing axial compression ratio. The test results indicate that shallow‐buried rectangular stations are susceptible to flexure‐controlled structural failure when their central columns possess a relatively low axial compression ratio and a high shear span‐to‐depth ratio. The failure mechanism of station columns is revealed by both the hybrid simulations and quasi‐static tests, and the findings from the full‐scale tests are beneficial for the practical design of shallow‐buried rectangular stations. [ABSTRACT FROM AUTHOR]

The first 500 kV AC cross‐linked polyethylene (XLPE) cable in the world has been installed in China in 2019. The insulation performance of insulation material under the electro‐thermal stress is the basis for its service life. At here, the AC breakdown voltage values and the breakdown time of the 500 kV AC XLPE submarine cable insulation material under the electro‐thermal step stress was analyzed. The lifetime prediction accuracy of a new proposed model was compared to the classic FALLOU, SIMONI/RAMU and CRINE lifetime model. Results show that the AC breakdown strength and lifetime of the XLPE samples increase slowly at low temperatures (40–65°C) and decrease rapidly at high temperatures (65–85°C). The lifetime prediction error of the classic FALLOU, SIMONI/RAMU and CRINE models present that their fit goodness cannot meet the accuracy requirement. The new lifetime model using stepwise regression method could optimize the combination of variables, which considers the coupling effect of electrical and thermal stress. The evaluation error of the new proposed model is better than the FALLOU, SIMONI/RAMU and CRINE model, which is suitable for analyzing the lifetime of the AC 500 kV XLPE submarine cable insulation material. [ABSTRACT FROM AUTHOR]

In recent years, an increasing number of circular RNAs (circRNAs) have been discovered in hepatocellular carcinoma (HCC). However, the functions of most circRNAs require further investigation. Here, we found that circBACH1 was significantly upregulated in HCC tissues and that high circBACH1 levels were closely associated with poor prognosis. In addition, circBACH1 could promote HCC growth by accelerating cell cycle progression in vitro and in vivo. We next investigated the cellular and molecular mechanisms and discovered that circBACH1 inhibited p27 translation, which influenced cell cycle progression. Moreover, we revealed that circBACH1 could combine directly with HuR using RNA immunoprecipitation assays, pull‐down assays, and electrophoretic mobility shift assays. The combination of these molecules facilitated HuR translocation from the nucleus to the cytoplasm according to the fluorescence in situ hybridization and immunofluorescence results. Finally, silencing HuR abrogated circBACH1's inhibition of p27 translation and abolished the circBACH1‐induced effect on HCC proliferation. In sum, circBACH1 plays a significant role as an oncogene through the circBACH1/HuR/p27 axis in HCC development. [ABSTRACT FROM AUTHOR]

Metabolite analysis or metabolomics is an important component of systems biology in the post-genomic era. Although separate liquid chromatography (LC) methods for quantification of the major classes of polar metabolites of plants have been available for decades, a single method that enables simultaneous determination of hundreds of polar metabolites is possible only with gas chromatography-mass spectrometry (GC-MS) techniques. The rapid expansion of new LC stationary phases in the market and the ready access of mass spectrometry in many laboratories provides an excellent opportunity for developing LC-MS based methods for multi-target quantification of polar metabolites. Although various LC-MS methods have been developed over the last 10 years with the aim to quantify one or more classes of polar compounds in different matrices, currently there is no consensus LC-MS method that is widely used in plant metabolomics studies. The most promising methods applicable to plant metabolite analysis will be reviewed in this paper and the major problems encountered highlighted. The aim of this review is to provide plant scientists, with limited to moderate experience in analytical chemistry, with up-to-date and simplified information regarding the current status of polar metabolite analysis using LC-MS techniques. [ABSTRACT FROM AUTHOR]