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Impact of cable sag on the efficiency of an inertial mass damper in controlling stay cable vibrations
Zhi-hao Wang,Hui Gao,Yan-wei Xu,Zheng-qing Chen,Hao Wang 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.1
Passive negative stiffness dampers (NSDs) that possess superior energy dissipation abilities, have been proved to be more efficient than commonly adopted passive viscous dampers in controlling stay cable vibrations. Recently, inertial mass dampers (IMDs) have attracted extensive attentions since their properties are similar to NSDs. It has been theoretically predicted that superior supplemental damping can be generated for a taut cable with an IMD. This paper aims to theoretically investigate the impact of the cable sag on the efficiency of an IMD in controlling stay cable vibrations, and experimentally validate superior vibration mitigation performance of the IMD. Both the numerical and asymptotic solutions were obtained for an inclined sag cable with an IMD installed close to the cable end. Based on the asymptotic solution, the cable attainable maximum modal damping ratio and the corresponding optimal damping coefficient of the IMD were derived for a given inertial mass. An electromagnetic IMD (EIMD) with adjustable inertial mass was developed to investigate the effects of inertial mass and cable sag on the vibration mitigation performance of two model cables with different sags through series of first modal free vibration tests. The results show that the sag generally reduces the attainable first modal damping ratio of the cable with a passive viscous damper, while tends to increase the cable maximum attainable modal damping ratio provided by the IMD. The cable sag also decreases the optimum damping coefficient of the IMD when the inertial mass is less than its optimal value. The theoretically predicted first modal damping ratio of the cable with an IMD, taking into account the sag generally, agrees well with that identified from experimental results, while it will be significantly overestimated with a taut-cable model, especially for the cable with large sag.
Vibration control of a stay cable with a rotary electromagnetic inertial mass damper
Zhi Hao Wang,Yan Wei Xu,Hui Gao,Zheng Qing Chen,Kai Xu,Shun Bo Zhao 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.6
Passive control may not provide enough damping for a stay cable since the control devices are often restricted to a low location level. In order to enhance control performance of conventional passive dampers, a new type of damper integrated with a rotary electromagnetic damper providing variable damping force and a flywheel serving as an inertial mass, called the rotary electromagnetic inertial mass damper (REIMD), is presented for suppressing the cable vibrations in this paper. The mechanical model of the REIMD is theoretically derived according to generation mechanisms of the damping force and the inertial force, and further validated by performance tests. General dynamic characteristics of an idealized taut cable with a REIMD installed close to the cable end are theoretically investigated, and parametric analysis are then conducted to investigate the effects of inertial mass and damping coefficient on vibration control performance. Finally, vibration control tests on a scaled cable model with a REIMD are performed to further verify mitigation performance through the first two modal additional damping ratios of the cable. Both the theoretical and experimental results show that control performance of the cable with the REIMD are much better than those of conventional passive viscous dampers, which mainly attributes to the increment of the damper displacement due to the inertial mass induced negative stiffness effects of the REIMD. Moreover, it is concluded that both inertial mass and damping coefficient of an optimum REIMD will decrease with the increase of the mode order of the cable, and oversize inertial mass may lead to negative effect on the control performance.
Wang, Tian-Yan,Xu, Zhi-Wen,Wang, Kun-Hao,Wang, Ning Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9
Abnormally expressed microRNAs (miRNAs) and genes have been found to play key roles in esophageal squamous cell carcinoma (ESCC), but little is known about the underlying mechanisms. The aim of this paper was to assess inter-relationships and the regulatory mechanisms of ESCC through a network-based approach. We built three regulatory networks: an abnormally expressed network, a related network and a global network. Unlike previous examples, containing information only on genes or miRNAs, the prime focus was on relationships. It is worth noting that abnormally expressed network emerged as a fault map of ESCC. Theoretically, ESCC might be treated and prevented by correcting the included errors. In addition, the predicted transcription factors (TFs) obtained by the P-match method also warrant further study. Our results may further guide gene therapy researchers in the study of ESCC.
Wang, Xu De,Su, Guang Yue,Zhao, Chen,Qu, Fan Zhi,Wang, Peng,Zhao, Yu Qing The Korean Society of Ginseng 2018 Journal of Ginseng Research Vol.42 No.2
Background: AD-2 (20(R)-dammarane-3b, 12b, 20, 25-tetrol; 25-OH-PPD) is a ginsenoside and isolated from Panax ginseng, showing anticancer activity against extensive human cancer cell lines. In this study, effects and mechanisms of 1C ((20R)-3b-O-(L-alanyl)-dammarane-12b, 20, 25-triol), a modified version of AD-2, were evaluated for its development as a novel anticancer drug. Methods: MTT assay was performed to evaluate cell cytotoxic activity. Cell cycle and levels of reactive oxygen species (ROS) were determined using flow cytometry analysis. Western blotting was employed to analyze signaling pathways. Results: 1C concentration-dependently reduces prostate cancer cell viability without affecting normal human gastric epithelial cell line-1 viability. In LNCaP prostate cancer cells, 1C triggered apoptosis via Bcl-2 family-mediated mitochondria pathway, downregulated expression of mouse double minute 2, upregulated expression of p53 and stimulated ROS production. ROS scavenger, N-acetylcysteine, can attenuate 1C-induced apoptosis. 1C also inhibited the proliferation of LNCaP cells through inhibition on $Wnt/{\beta}-catenin$ signaling pathway. Conclusion: 1C shows obvious anticancer activity based on inducing cell apoptosis by Bcl-2 family-mediated mitochondria pathway and ROS production, inhibiting $Wnt/{\beta}-catenin$ signaling pathway. These findings demonstrate that 1C may provide leads as a potential agent for cancer therapy.
Wang, Zhi,Xu, Weizhou,Kang, Jiyue,Li, Min,Huang, Jin,Ke, Qingbo,Kim, Ho Soo,Xu, Bingcheng,Kwak, Sang-Soo Elsevier 2018 Vol. No.
<P><B>Abstract</B></P> <P>The multifunctional Orange (Or) protein plays crucial roles in carotenoid homeostasis, photosynthesis stabilization, and antioxidant activity in plants under various abiotic stress conditions. The <I>Or</I> gene has been cloned in several crops but not in alfalfa (<I>Medicago sativa</I> L.). Alfalfa is widely cultivated across the world; however, its cultivation is largely limited by various abiotic stresses, including drought. In this study, we isolated the <I>Or</I> gene from alfalfa (<I>MsOr</I>) cv. Xinjiang Daye. The amino acid sequence of the deduced MsOr protein revealed that the protein contained two trans-membrane domains and a DnaJ cysteine-rich zinc finger domain, and showed a high level of similarity with the Or protein of other plants species. The MsOr protein was localized in leaf chloroplasts of tobacco. The expression of <I>MsOr</I> was the highest in mature leaves and was significantly induced by abiotic stresses, especially drought. To perform functional analysis of the <I>MsOr</I> gene, we overexpressed <I>MsOr</I> gene in tobacco (<I>Nicotiana benthamiana</I>). Compared with wild-type (WT) plants, transgenic tobacco lines showed higher carotenoid accumulation and increased tolerance to various abiotic stresses, including drought, heat, salt, and methyl viologen-mediated oxidative stress. Additionally, contents of hydrogen peroxide and malondialdehyde were lower in the transgenic lines than in WT plants, suggesting superior membrane stability and antioxidant capacity of TOR lines under multiple abiotic stresses. These results indicate the <I>MsOr</I> gene as a potential target for the development of alfalfa cultivars with enhanced carotenoid content and tolerance to multiple environmental stresses.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Orange (<I>MsOr</I>) gene from alfalfa was isolated and characterized in transgenic tobacco. </LI> <LI> <I>MsOr</I> gene was localized to chloroplasts and strongly induced by abiotic stresses including drought. </LI> <LI> <I>MsOr</I> expressing tobacco plants showed enhanced tolerance to drought, heat, salt and oxidative stress. </LI> </UL> </P>
Li, Xin,Wang, Yang,Li, Xing-Wang,Liu, Bao-Cheng,Zhao, Qing-Zhu,Li, Wei-Dong,Chen, Shi-Qing,Huang, Xiao-Ye,Yang, Feng-Ping,Wang, Quan,Wang, Jin-Fen,Xiao, Yan-Zeng,Xu, Yi-Feng,Feng, Guo-Yin,Peng, Zhi-Ha Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5
Colorectal cancer (CRC), now the third most common cancer across the world, is known to aggregate in families. USP7 is a very important protein with an important role in regulating the p53 pathway, which is critical for genomic stability and tumor suppression. We here genotyped eight SNPs within the USP7 gene and conducted a case-control study in 312 CRC patients and 270 healthy subjects in the Chinese Han population. No significant associations were found for any single SNP and CRC risk. Our data eliminate USP7 as a potential candidate gene towards for CRC in the Han Chinese population.
Xue, Lu-Chen,Xu, Zhi-Wen,Wang, Kun-Hao,Wang, Ning,Zhang, Xiao-Xu,Wang, Shang Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.2
Genes and microRNAs (miRNAs) have important roles in human oncology. However, most of the biological factors are reported in disperse form which makes it hard to discover the pathology. In this study, genes and miRNAs involved in human endometrial cancer(EC) were collected and formed into regulatory networks following their interactive relations, including miRNAs targeting genes, transcription factors (TFs) regulating miRNAs and miRNAs included in their host genes. Networks are constructed hierarchically at three levels: differentially expressed, related and global. Among the three, the differentially expressed network is the most important and fundamental network that contains the key genes and miRNAs in EC. The target genes, TFs and miRNAs are differentially expressed in EC so that any mutation in them may impact on EC development. Some key pathways in networks were highlighted to analyze how they interactively influence other factors and carcinogenesis. Upstream and downstream pathways of the differentially expressed genes and miRNAs were compared and analyzed. The purpose of this study was to partially reveal the deep regulatory mechanisms in EC using a new method that combines comprehensive genes and miRNAs together with their relationships. It may contribute to cancer prevention and gene therapy of EC.