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      • KCI등재

        Thermal and Mechanical Response of Soil and Tunnel during Replacement of Shield Tail Brush by Freezing Method

        Xu-Yang Wang,Da-Jun Yuan,Da-Long Jin,Wei-Lin Su 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.5

        In the long-distance shield tunneling process, the shield tail brush needs to be replaced after wear failure, especially in cross-river and cross-sea tunnel projects. Taking the shield tail brush replacement project of Qingchun Road tunnel in Hangzhou, China as the research background, a three-dimensional sequential thermo-mechanical coupled numerical simulation was carried out to study the shield tail brush replacement with liquid nitrogen freezing by ABAQUS software. The development of temperature fields and displacement fields of soil, and the deformations of the tunnel sections along the longitudinal direction induced by freezing were obtained. The numerical model was further validated by site measurement. In addition, the effects of the frozen wall thickness, buried depth, excavation radius, and coefficients of linear thermal expansion of soils on the frost heave were studied.

      • KCI등재

        RNAi suppression of nuclear receptor genes results in increased susceptibility to sulfoxaflor in brown planthopper, Nilaparvata lugens

        Lu Xu,Chun-Qing Zhao,De-Jin Xu,Guang-Chun Xu,Xiao-Long Xu,Zhao-Jun Han,Ya-Nan Zhang,Zhong-Yan Gu 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.2

        Nuclear receptors (NRs), which belong to a superfamily of ligand-dependent transcription factors, play essential roles in gene regulation to affect numerous physiological pathways. Twenty NR genes were identified in Nilaparvata lugens by using genomic, transcriptomic and GenBank databases, and categorized into NR0-NR6 subfamilies according to standard nomenclature. Among them, three NR geneswere classed into NR0, four into NR1, eight into NR2, one into NR3, one into NR4, two into NR5, and one into NR6, respectively. A phylogenetic tree of NRs from N. lugens and other representative species was constructed, which provided evolutionary insight into genetic distance. In order to investigate the NRs,whichwere induced by sulfoxaflor, time- and tissue-specific expression profiles of NR genes in fourth-instar nymphs were determined following LD50 sulfoxaflor treatment (0.28 ng/insect) and compared with control samples. NlUSP, NlE78, NlTLL, NlHR51, NlHR83, NlPNR and NlFTZ-F1 were highly expressed following 12–48 h of sulfoxaflor treatment. NlHR39 and NlDSF transcripts were detected in the head and the thorax, respectively. High-level and constitutive expression of NlHR3, NlTLL, NlHR83, NlFTZF1 and NlHR4 were found in the abdomen. Feeding of dsRNAs reduced the expression of NlHR3, NlUSP, NlTLL, NlHR83, NlPNR, NlFTZ-F1 and NlHR4 (35.48–49.77%) and caused significant nymph mortality (69.21–81.45%). These NRs, considered as insecticide targets, may play important function in sulfoxaflor detoxification.

      • KCI등재

        Modeling and Simulation of the Magnetic Method for High Voltage Direct Current Inspection Robot

        Xian-jin Xu,Cheng-hui Liu,Yu Yan,Hao-da Chen,Lei Fang,Yun-long Wang,Long-hui Wu 한국자기학회 2018 Journal of Magnetics Vol.23 No.3

        In order to solve the slipping problem of a two-arm-wheel combined inspection robot, a maglev system based on the magnetic field of a high voltage direct current (HVDC) is proposed. The magnetic system comprises of two parts: a magnetic levitation system and a magnetic drive system. The levitation component overcomes the gravity of the robot by the Ampere force generated by current-carrying coils in the magnetic field of HVDC. The drive component utilizes the Ampere force generated by current-carrying coils in the magnetic field of HVDC as the driving force. Simulation results of the model are compared with the calculated values. The results show that the magnetic levitation method and the magnetic drive method are theoretically feasible, and the model is accurate and effective, which is of great practical significance to the physical realization of the inspection robot.

      • KCI등재후보

        Displacement-based design approach for highway bridges with SMA isolators

        Jin-long Liu,Songye Zhu,You-lin Xu,Yunfeng Zhang 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.8 No.2

        As a practical and effective seismic resisting technology, the base isolation system has seen extensive applications in buildings and bridges. However, a few problems associated with conventional leadrubber bearings have been identified after historical strong earthquakes, e.g., excessive permanent deformations of bearings and potential unseating of bridge decks. Recently the applications of shape memory alloys (SMA) have received growing interest in the area of seismic response mitigation. As a result, a variety of SMA-based base isolators have been developed. These novel isolators often lead to minimal permanent deformations due to the self-centering feature of SMA materials. However, a rational design approach is still missing because of the fact that conventional design method cannot be directly applied to these novel devices. In light of this limitation, a displacement-based design approach for highway bridges with SMA isolators is proposed in this paper. Nonlinear response spectra, derived from typical hysteretic models for SMA, are employed in the design procedure. SMA isolators and bridge piers are designed according to the prescribed performance objectives. A prototype reinforced concrete (RC) highway bridge is designed using the proposed design approach. Nonlinear dynamic analyses for different seismic intensity levels are carried out using a computer program called “OpenSees”. The efficacy of the displacement-based design approach is validated by numerical simulations. Results indicate that a properly designed RC highway bridge with novel SMA isolators may achieve minor damage and minimal residual deformations under frequent and rare earthquakes. Nonlinear static analysis is also carried out to investigate the failure mechanism and the self-centering ability of the designed highway bridge.

      • SCOPUSKCI등재

        Synthesis of a Novel Phosphorus-containing Flame Retardant for Epoxy Resins

        Xu, Hong-Jun,Jin, Fan-Long,Park, Soo-Jin Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.11

        In this study, a novel phosphorus-containing flame retardant copolymer of spirocyclic pentaerythritol di(phosphate monochloride) and bisphenol S (SPD-BS) was successfully synthesized and used as a flame retardant in diglycidyl ether of bisphenol A (DGEBA) epoxy resins. The chemical structure of the SPD-BS was characterized using FT-IR and $^1H$ NMR spectra. The thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The effects of SPD-BS and nano-$CaCO_3$ on the flame-retardant properties of DGEBA/SPD-BS systems were evaluated by measurement of the burning rate. As a result, the thermal stabilities of the DGEBA/SPD-BS systems were decreased with increasing SPD-BS content. The flame-retardant properties and char yields of the systems were significantly increased when SPD-BS content increased. The synergism of nano-$CaCO_3$ incorporation on flame retardancy was found for the DGEBA/SPD-BS systems.

      • KCI등재

        Tentative identification of 20(S)-protopanaxadiol metabolites in human plasma and urine using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry

        Jin Ling,Yingjia Yu,Jiakun Long,Yan Li,Jiebing Jiang,Liping Wang,Changjiang Xu,Gengli Duan 고려인삼학회 2019 Journal of Ginseng Research Vol.43 No.4

        Background: 20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides,possesses antidepressant activity among many other pharmacological activities. It is currently undergoingclinical trial in China as an antidepressant. Methods: In this study, an ultra-performance liquid chromatography coupled with triple quadrupoletime-of-flight mass tandem mass spectrometry method was established to identify the metabolites ofPPD in human plasma and urine following oral administration in phase IIa clinical trial. Results: A total of 40 metabolites in human plasma and urine were identified using this method. Fourmetabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidatethe exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compoundswere found as metabolites in human for the first time. Upon comparing our findings with the findings ofthe in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metaboliteswith m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments. Conclusion: The metabolites identified using ultra-performance liquid chromatography coupled withtriple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. Themain metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolicpathways of PPD in vivo (human) were proposed based on structural analysis.

      • Loss of Heterozygosity at the Calcium Regulation Gene Locus on Chromosome 10q in Human Pancreatic Cancer

        Long, Jin,Zhang, Zhong-Bo,Liu, Zhe,Xu, Yuan-Hong,Ge, Chun-Lin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

        Background: Loss of heterozygosity (LOH) on chromosomal regions is crucial in tumor progression and this study aimed to identify genome-wide LOH in pancreatic cancer. Materials and Methods: Single-nucleotide polymorphism (SNP) profiling data GSE32682 of human pancreatic samples snap-frozen during surgery were downloaded from Gene Expression Omnibus database. Genotype console software was used to perform data processing. Candidate genes with LOH were screened based on the genotype calls, SNP loci of LOH and dbSNP database. Gene annotation was performed to identify the functions of candidate genes using NCBI (the National Center for Biotechnology Information) database, followed by Gene Ontology, INTERPRO, PFAM and SMART annotation and UCSC Genome Browser track to the unannotated genes using DAVID (the Database for Annotation, Visualization and Integration Discovery). Results: The candidate genes with LOH identified in this study were MCU, MICU1 and OIT3 on chromosome 10. MCU was found to encode a calcium transporter and MICU1 could encode an essential regulator of mitochondrial $Ca^{2+}$ uptake. OIT3 possibly correlated with calcium binding revealed by the annotation analyses and was regulated by a large number of transcription factors including STAT, SOX9, CREB, NF-kB, PPARG and p53. Conclusions: Global genomic analysis of SNPs identified MICU1, MCU and OIT3 with LOH on chromosome 10, implying involvement of these genes in progression of pancreatic cancer.

      • SCIESCOPUSKCI등재

        Tentative identification of 20(S)-protopanaxadiol metabolites in human plasma and urine using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry

        Ling, Jin,Yu, Yingjia,Long, Jiakun,Li, Yan,Jiang, Jiebing,Wang, Liping,Xu, Changjiang,Duan, Gengli The Korean Society of Ginseng 2019 Journal of Ginseng Research Vol.43 No.4

        Background: 20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides, possesses antidepressant activity among many other pharmacological activities. It is currently undergoing clinical trial in China as an antidepressant. Methods: In this study, an ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass tandem mass spectrometry method was established to identify the metabolites of PPD in human plasma and urine following oral administration in phase IIa clinical trial. Results: A total of 40 metabolites in human plasma and urine were identified using this method. Four metabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidate the exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compounds were found as metabolites in human for the first time. Upon comparing our findings with the findings of the in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metabolites with m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z 505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments. Conclusion: The metabolites identified using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. The main metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolic pathways of PPD in vivo (human) were proposed based on structural analysis.

      • Prognostic Significance of Overexpression of EZH2 and H3k27me3 Proteins in Gastric Cancer

        He, Long-Jun,Cai, Mu-Yan,Xu, Guo-Liang,Li, Jian-Jun,Weng, Zi-Jin,Xu, Da-Zhi,Luo, Guang-Yu,Zhu, Sen-Lin,Xie, Dan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

        The enhancer of zeste homolog 2 (EZH2) methyl transferase and histone 3 lysine 27 (H3K27me3) protein can repress gene transcription, and their aberrant expression has been observed in various human cancers. This study determined their expression levels in gastric cancer tissues with reference to clinicopathological features and patient survival. We collected 117 gastric cancer and corresponding normal tissues for immunohistochemistry analysis. In gastric cancers, 82/117 (70.1%) were positive for EZH2 and 66/117 (56.4%) for H3K27me3 proteins in contrast to only 5.41% and 7.25% of normal gastric mucosa specimens, respectively. Kaplan-Meier survival data showed the average overall and disease-free survival of EZH2 high expression patients was 25.2 and 20.2 months, respectively, shorter than that with EZH2 low expression (40.5 and 35.9 months). The average overall survival and disease-free survival of high H3K27me3 expression patients was 23.4 and 17.4 months, shorter than without H3K27me3 expression (37.6 and 34.5 months). The average overall survival and disease-free survival of patients with both EZH2 and H3K27me3 expression was 18.8 and 12.9 months, respectively, shorter than that with either alone (34.7 and 31.2 months) or with low levels of both (43.9 and 39.9 months). Multivariate Cox regression analysis showed that H3K27me3 and EZH2 expression, tumor size differentiation and clinical stage were all independent prognostic factors for predicting patient survival. This study demonstrated that detection of both EZH2 and H3K27me3 proteins can predict poor survival of gastric cancer patients, superior to single protein detection. In addition, H3K27me3 and EZH2 protein expression could predict lymph node metastasis.

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