Studies on seismic performance of the new section steel beam-wall connection joint

Weicheng Su,Jian Liu,Changjiang Liu,Chiyu Luo,Weihua Ye,Yaojun Deng 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.5

This paper introduces a new hybrid structural connection joint that combines shear walls with section steel beams, fundamentally resolving the construction complexity issue of requiring pre-embedded connectors in the connection between shear walls and steel beams. Initially, a quasi-static loading scheme with load-deformation dual control was employed to conduct low-cycle repeated loading experiments on five new connection joints. Data was acquired using displacement and strain gauges to compare the energy dissipation coefficients of each specimen. The destruction process of the new connection joints was meticulously observed and recorded, delineating it into three stages. Hysteresis curves and skeleton curves of the joint specimens were plotted based on experimental results, summarizing the energy dissipation performance of the joints. It's noteworthy that the addition of shear walls led to an approximate 17% increase in the energy dissipation coefficient. The energy dissipation coefficients of dog-bone-shaped connection joints with shear walls and cover plates reached 2.043 and 2.059, respectively, exhibiting the most comprehensive hysteresis curves. Additionally, the impact of laminated steel plates covering composite concrete floors on the stiffness of semi-rigid joint ends under excessive stretching should not be disregarded. A comparison with finite element analysis results yielded an error of merely 2.2%, offering substantial evidence for the wide-ranging application prospects of this innovative joint in seismic performance.

Construction of a Streptomyces lydicus A01 Transformant with a chit42 Gene from Trichoderma harzianum P1 and Evaluation of Its Biocontrol Activity against Botrytis cinerea

Qiong Wu,Linquan Bai,Weicheng Liu,Yingying Li,Caige Lu,Yaqian Li,Kehe Fu,Chuanjin Yu,Jie Chen 한국미생물학회 2013 The journal of microbiology Vol.51 No.2

Streptomyces lydicus A01 and Trichoderma harzianum P1are potential biocontrol agents of fungal diseases in plants. S. lydicus A01 produces natamycin to bind the ergosterol of the fungal cell membrane and inhibits the growth of Botrytis cinerea. T. harzianum P1, on the other hand, features high chitinase activity and decomposes the chitin in the cell wall of B. cinerea. To obtain the synergistic biocontrol effects of chitinase and natamycin on Botrytis cinerea, this study transformed the chit42 gene from T. harzianum P1 to S. lydicus A01. The conjugal transformant (CT) of S. lydicus A01 with the chit42 gene was detected using polymerase chain reaction (PCR). Associated chitinase activity and natamycin production were examined using the 3, 5-dinitrosalicylic acid (DNS)method and ultraviolet spectrophotometry, respectively. The S. lydicus A01-chit42 CT showed substantially higher chitinase activity and natamycin production than its wild type strain (WT). Consequently, the biocontrol effects of S. lydicus A01-chit42 CT on B. cinerea, including inhibition to spore germination and mycelial growth, were highly improved compared with those of the WT. Our research indicates that the biocontrol effect of Streptomyces can be highly improved by transforming the exogenous resistance gene, i.e. chit42from Trichoderma, which not only enhances the production of antibiotics, but also provides a supplementary function by degrading the cell walls of the pathogens.

A Novel Relational Database Watermarking Algorithm Based on Clustering and Polar Angle Expansion

Zhiyong Li,Junmin Liu,Weicheng Tao 보안공학연구지원센터 2013 International Journal of Security and Its Applicat Vol.7 No.2

Ginsenoside F2 enhances glucose metabolism by modulating insulin signal transduction in human hepatocarcinoma cells

Shengqiang Han,Long You,Yeye Hu,Tingwu Liu,Jae Youl Cho,Weicheng Hu,Shuai Wei The Korean Society of Ginseng 2023 Journal of Ginseng Research Vol.47 No.3

Background: Ginsenoside F2 (GF2), a minor component of Panax ginseng, has been reported to possess a wide variety of pharmacological activities. However, its effects on glucose metabolism have not yet been reported. Here, we investigated the underlying signaling pathways involved in its effects on hepatic glucose. Methods: HepG2 cells were used to establish insulin-resistant (IR) model and treated with GF2. Cell viability and glucose uptake-related genes were also examined by real-time PCR and immunoblots. Results: Cell viability assays showed that GF2 up to 50 μM did not affect normal and IR-HepG2 cell viability. GF2 reduced oxidative stress by inhibiting phosphorylation of the mitogen-activated protein kinases (MAPK) signaling components such as c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 MAPK, and reducing the nuclear translocation of NF-κB. Furthermore, GF2 activated PI3K/AKT signaling, upregulated the levels of glucose transporter 2 (GLUT-2) and GLUT-4 in IR-HepG2 cells, and promoted glucose absorption. At the same time, GF2 reduced phosphoenolpyruvate carboxykinase and glucose-6-phosphatase expression as well as inhibiting gluconeogenesis. Conclusion: Overall, GF2 improved glucose metabolism disorders by reducing cellular oxidative stress in IR-HepG2 cells via MAPK signaling, participating in the PI3K/AKT/GSK-3β signaling pathway, promoting glycogen synthesis, and inhibiting gluconeogenesis.

Two new triterpenoid saponins derived from the leaves of Panax ginseng and their antiinflammatory activity

Fuli Li,Yufeng Cao,Tingwu Liu,Guilong Yan,Liang Chen,Lilian Ji,Lun Wang,Bin Chen,Aftab Yaseen,Ashfaq A. Khan,Guo-Lin Zhang,Yunyao Jiang,Jianxun Liu,Gongcheng Wang,Ming-Kui Wang,Weicheng Hu 고려인삼학회 2019 Journal of Ginseng Research Vol.43 No.4

Background: The leaves and roots of Panax ginseng are rich in ginsenosides. However, the chemical compositionsof the leaves and roots of P. ginseng differ, resulting in different medicinal functions. In recent years,the aerial parts of members of the Panax genus have received great attention fromnatural product chemistsas producers of bioactive ginsenosides. The aim of this study was the isolation and structural elucidation ofnovel, minor ginsenosides in the leaves of P. ginseng and evaluation of their antiinflammatory activity in vitro. Methods: Various chromatographic techniques were applied to obtain pure individual compounds, andtheir structures were determined by nuclear magnetic resonance and high-resolution mass spectrometry,as well as chemical methods. The antiinflammatory effect of the new compounds was evaluated onlipopolysaccharide-stimulated RAW 264.7 cells. Results and conclusions: Two novel, minor triterpenoid saponins, ginsenoside LS1 (1) and 5,6-didehydroginsenoside Rg3 (2), were isolated from the leaves of P. ginseng. The isolated compounds 1and 2 were assayed for their inhibitory effect on nitric oxide production in LPS-stimulated RAW 264.7cells, and Compound 2 showed a significant inhibitory effect with IC50 of 37.38 mM compared with that ofNG-monomethyl-L-arginine (IC50 ¼ 90.76 mM). Moreover, Compound 2 significantly decreased secretionof cytokines such as prostaglandin E2 and tumor necrosis factor-a. In addition, Compound 2 significantlysuppressed protein expression of inducible nitric oxide synthase and cyclooxygenase-2. These resultssuggested that Compound 2 could be used as a valuable candidate for medicinal use or functional food,and the mechanism is warranted for further exploration.

AR model-based crosstalk cancellation method for operational transfer path analysis

Wei Cheng,Yan Zhu,Xuefeng Chen,Chao Song,Le Zhang,Lin Gao,Yilong Liu,Zelin Nie,Hongrui Cao,Yang Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.3

To reduce the crosstalk effects between the signals at reference points in operational transfer path analysis (OTPA) and improve the reliability of solutions, a novel OTPA method based on auto-regressive (AR) model is proposed in this paper. The key to this method is to obtain the power spectrum by AR model for estimating the prior transmissibility function matrix. Firstly, in view of the lack of noise reduction process in conventional crosstalk cancellation method, singular value decomposition (SVD) is applied to reduce the noise of original signals. Secondly, Burg algorithm is used to calculate AR model parameters. Thirdly, auto-power spectrum and cross-power spectrum are obtained by AR model and the periodogram method respectively. Fourthly, the transmissibility function matrix is obtained by Landweber iterative method based on corrected signals at reference points. Finally, the proposed method can significantly reduce the crosstalk effects, resulting in more accurate evaluation of transfer path contributions. Generally, this study can provide accurate and reliable evidences for vibration & noise monitoring and reduction for mechanical systems, and thus benefit for the active control of vibration & noise.