Amplitude dependency of damping of tall structures by the random decrement technique

An Xu,Zhuangning Xie,Ming Gu,Jiurong Wu 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.21 No.2

This study focuses on the amplitude dependency of damping of tall structures by the random decrement technique (RDT). Many researchers have adopted RDT to establish the amplitude dependency of damping ratios in super-tall buildings under strong wind loads. In this study, a series of simulated examples were analyzed to examine the reliability of this method. Results show that damping ratios increase as vibration amplitudes increase in several cases; however, the damping ratios in the simulated signals were preset as constants. This finding reveals that this method and the derived amplitude-dependent damping ratio characteristics are unreliable. Moreover, this method would obviously yield misleading results if the simulated signals contain Gaussian white noise. Full-scale measurements on a super-tall building were conducted during four typhoons, and the recorded data were analyzed to observe the amplitude dependency of damping ratio. Relatively wide scatter is observed in the resulting damping ratios, and the damping ratios do not appear to have an obvious nonlinear relationship with vibration amplitude. Numerical simulation and field measurement results indicate that the widely-used method for establishing the amplitude-dependent damping characteristics of super-tall buildings and the conclusions derived from it might be questionable at the least. More field-measured data must be collected under strong wind loads, and the damping characteristics of super-tall buildings should be investigated further.

Static behaviors of self-anchored and partially earth-anchored long-span cable-stayed bridges

Xie, Xu,Yamaguchi, Hiroki,Nagai, Masatsugu Techno-Press 1997 Structural Engineering and Mechanics, An Int'l Jou Vol.5 No.6

In this paper, three dimensional static behaviors of the self-anchored and partially earth-anchored cable-stayed bridges, with a span of 1400 meters, under wind loading are studied by using a 3D geometrical nonlinear analysis. In this analysis, the bridges both after completion and under construction are dealt with. The wind resistant characteristics of the both cable-stayed systems are made clear. In particular, the characteristics of the partially earth-anchored cable systems, which is expected to be a promising solution for extending the span of the cable-stayed systems further, is presented.

Luciferase Assay to Screen Tumour-specific Promoters in Lung Cancer

Xu, Rong,Guo, Long-Jiang,Xin, Jun,Li, Wen-Mao,Gao, Yan,Zheng, You-Xian,Guo, You-Hong,Lin, Yang-Jun,Xie, Yong-Hua,Wu, Ya-Qing,Xu, Rui-An Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11

Objective: Specific promoters could improve efficiency and ensure the safety of gene therapy. The aim of our study was to screen examples for lung cancer. Methods: The firefly luciferase gene was used as a reporter, and promoters based on serum markers of lung cancer were cloned. The activity and specificity of seven promoters, comprising CEACAM5 (carcinoembryonic antigen, CEA), GRP (Gastrin-Releasing Peptide), KRT19 (cytokeratin 19, KRT), SFTPB (surfactant protein B, SP-B), SERPINB3 (Squamous Cell Carcinoma Antigen, SCCA), SELP (Selectin P, Granule Membrane Protein 140kDa, Antigen CD62, GMP) and DKK1 (Dickkopf-1) promoters were compared in lung cancer cells to obtain cancer-specific examples with strong activity. Results: The CEACAM5, DKK1, GRP, SELP, KRT19, SERPINB3 and SFTPB promoters were cloned. Furthermore, we successfully constructed recombinant vector pGL-CEACAM5 (DKK1, GRP, SELP, KRT19, SERPINB3 and SFTPB) contained the target gene. After cells were transfectedwith recombinant plasmids, we found that the order of promoter activity from high to low was SERPINB3, DKK1, SFTPB, KRT19, CEACAM5, SELP and GRP and the order for promoters regarding specificity and high potential were SERPINB3, DKK1, SELP, SFTPB, CEACAM5, KRT19 and GRP. Conclusion: The approach adopted is feasible to screen for new tumour specific promoters with biomarkers. In addition, the screened lung-specific promoters might have potential for use in lung cancer targeted gene therapy research.

Synthesis and Characterization of pH and Temperature Sensitive Hydrogel Based on Poly(N-isopropylacrylamide), Poly(ε-caprolactone), Methylacrylic Acid, and Methoxyl Poly(ethylene glycol)

Xu Xu,Jia Song,Ke Wang,YingChun Gu,Feng Luo,XiaoHai Tang,Ping Xie,ZhiYong Qian 한국고분자학회 2013 Macromolecular Research Vol.21 No.8

In this paper, a novel biodegradable and pH/thermo-sensitive hydrogel based on poly(ε-caprolactone),methoxyl poly(ethylene glycol), methylacrylic acid and N-isopropylacrylamide was prepared by UV-initiated free radical polymerization. The hydrogels were characterized by Fourier transforms infrared ray. The thermal responsibility was investigated with the help of differential scanning calorimetry. Swelling behavior in aqueous medium with different pH value was studied in detail. When the pH value of the aqueous medium was increased from 1.2 to 7.2,the swelling ratio of the hydrogels increased accordingly. The morphology was observed by scanning electron microscopy, and the hydrolytic degradation behavior in different aqueous media (pH 1.2 and pH 7.2) was also investigated in detail. The prepared biodegradable pH/thermo-sensitive hydrogel based on poly(ε-caprolactone), methoxyl poly(ethylene glycol), methylacrylic acid and N-isopropylacrylamide hold great promise in the development of a smart drug delivery system.

Effects of Arachidonic Acid on the Calcium Channel Current $(I_{Ba})$ and on the Osmotic Stretch-induced Increase of $I_{Ba}$ in Guinea-Pig Gastric Myocytes

Xu, Wen-Xie,Kim, Sung-Joon,So, In-Suk,Suh, Suk-Hyo,Kim, Ki-Whan The Korean Society of Pharmacology 1997 The Korean Journal of Physiology & Pharmacology Vol.1 No.4

We employed the whole-cell patch clamp technique to investigate the effects of arachidonic acid (AA) on barium inward current through the L-type calcium channels ($I_{Ba}$) and on osmotic stretch-induced increase of $I_{Ba}$ in guinea-pig antral gastric myocytes. Under isosmotic condition, AA inhibited $I_{Ba}$ in a dose-dependent manner to $91.1{\pm}1.4,\;72.0{\pm}3.2,\;46.0{\pm}1.8,\;and\;20.3{\pm}2.3%$ at 1, 5, 10, 30 mM, respectively. The inhibitory effect of AA was not affected by 10 ${\mu}M$ indomethacin, a cyclooxygenase inhibitor. Other unsaturated fatty acids, linoleic acid (LA) and oleic acid (OA) were also found to suppress $I_{Ba}$ but stearic acid (SA), a saturated fatty acid, had no inhibitory effect on $I_{Ba}$. The potency sequence of these inhibitory effects was AA ($79.7{\pm}2.3%$) > LA ($43.1{\pm}2.7%$) > OA ($14.2{\pm}1.1%$) at 30 ${\mu}M$. On superfusing the myocyte with hyposmotic solution (214 mOsm) the amplitude of $I_{Ba}$ at 0 mV increased ($38.0{\pm}5.5%$); this increase was completely blocked by pretreatment with 30 mM AA, but not significantly inhibited by lower concentrations of AA (1, 5 and 10 ${\mu}M$) (P>0.05). Unsaturated fatty acids shifted the steady-state inactivation curves of $I_{Ba}$ to the left; the extent of shift caused by AA was greater than that caused by LA. The activation curve was not affected by AA or LA. The results suggest that AA and other unsaturated fatty acids directly modulate L-type calcium channels and AA might modulate the hyposmotic stretch- induced increase of L-type calcium channel current in guinea-pig gastric smooth muscle.

Meta-Analysis of the Diagnostic Efficacy of the Luminex xTAG Respiratory Viral Panel FAST v2 Assay for Respiratory Viral Infections

Xu-Guang Guo,Li-Min Xie,Xin Yin,Tian-Ao Xie,Jian-Wen Su,Qin Huang,Jing-Hao Zhang,Yin-Fei Huang 연세대학교의과대학 2022 Yonsei medical journal Vol.63 No.1

Purpose: Acute respiratory viral infections pose significant morbidity and mortality, making it essential to diagnose respiratory viral infections rapidly. In this study, the diagnostic efficacy of the Luminex xTAG Respiratory Virus Panel (RVP) FAST v2 test was evaluated on respiratory viral infections. Materials and Methods: Information was retrieved from electronic databases, including Embase, Web of Science, PubMed, and Cochrane Library, for systematic review. Studies that fulfilled predefined inclusion criteria were included. After the extraction of information, statistical software was utilized for quality evaluation, data analysis, and assessment of publication bias. Results: Eighty groups in fourfold tables from nine articles were included to perform statistical analyses. Therein, the mean specificity and mean sensitivity of Luminex xTAG RVP FAST v2 test for the detection of respiratory viral infections were 0.99 (0.98–0.99) and 0.88 (0.87–0.90), respectively. Additionally, the negative and positive likelihood ratios were 0.14 (0.11–0.19) and 87.42 (61.88–123.50), respectively. Moreover, the diagnostic odds ratio and area under the curve of summary receiver operating characteristic were 714.80 and 0.9886, respectively. Conclusion: The Luminex xTAG RVP FAST v2 test could be a reliable and rapid diagnostic method for multiple respiratory viral infections.

A Deformation History-Based Approach for Ultra-Low Cycle Fatigue Damage Evaluation of Steel Structures

Xie Xu,Cheng Cheng,Shuailing Li 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.4

Ultra-low cycle fatigue (ULCF) damage is one of the main failure modes of steel structures when subjected to intense earthquake action, such as near-fi eld action. However, existing ULCF evaluation methods are based on the plastic strain history of structures, which requires fi ne numerical simulation and causes high calculation cost. In order to improve and simplify the ULCF evaluation process for steel structures, a new damage index based on the structure deformation history was proposed in this paper, with the application of structure life curve and Miner’s rule. Two types of steel components, notched round steel bar and steel pier, were employed as the research objectives to verify the accuracy of proposed damage index. The predicted ULCF life was compared with the results of tests and fi nite element simulations, which showed that the application of damage index was of acceptable accuracy. Compared with the traditional plastic strain history-based ULCF evaluation methods, the advantage of proposed damage index is that ULCF life of a given steel structure can be determined quickly according to the loading condition once its life curve is realized, thus eliminating the cumbersome numerical simulation process.

Positive Real Control for Uncertain 2-D Singular Roesser Models

Huiling Xu,Lihua Xie,Shenyuan Xu,Yun Zou 대한전기학회 2005 International Journal of Control, Automation, and Vol.3 No.2

MicroRNA-576-3p Inhibits Proliferation in Bladder Cancer Cells by Targeting Cyclin D1

Liping Xie,Zhen Liang,Shiqi Li,Xin Xu,Xianglai Xu,Xiao Wang,Jian Wu,Yi Zhu,Zhenghui Hu,Yiwei Lin,Yeqing Mao,Hong Chen,Jindan Luo,Ben Liu,Xiangyi Zheng 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.2

MicroRNAs (miRNAs) are small, endogenous RNAs that play important gene-regulatory roles by binding to the imperfectly complementary sequences at the 3 -UTR of mRNAs and directing their gene expression. Here, we first discovered that miR-576-3p was down-regulated in human bladder cancer cell lines compared with the non-malignant cell line. To better characterize the role of miR-576-3p in bladder cancer cells, we over-expressed or down-regulated miR-576-3p in bladder cancer cells by transfecting with chemically synthesized mimic or inhibitor. The overexpression of miR-576-3p remarkably inhibited cell proliferation via G1-phase arrest, and decreased both mRNA and protein levels of cyclin D1 which played a key role in G1/S phase transition. The knock-down of miR-576-3p significantly promoted the proliferation of bladder cancer cells by accelerating the progression of cell cycle and increased the expression of cyclin D1. Moreover, the dual-luciferase reporter assays indicated that miR-576-3p could directly target cyclin D1 through binding its 3 -UTR. All the results demonstrated that miR-576-3p might be a novel suppressor of bladder cancer cell proliferation through targeting cyclin D1.

Effects of Arachidonic Acid on the Calcium Channel Current (<I>I</I><SUB>Ba</SUB>) and on the Osmotic Stretch-induced Increase of <I>I</I><SUB>Ba</SUB> in Guinea-Pig Gastric Myocytes

Wen Xie Xu,Sung Joon Kim,Insuk So,Suk Hyo Suh,Ki Whan Kim 대한생리학회-대한약리학회 1997 The Korean Journal of Physiology & Pharmacology Vol.1 No.4

<P> We employed the whole-cell patch clamp technique to investigate the effects of arachidonic acid (AA) on barium inward current through the L-type calcium channels (<I>I</I><SUB>Ba</SUB>) and on osmotic stretch-induced increase of <I>I</I><SUB>Ba</SUB> in guinea-pig antral gastric myocytes. Under isosmotic condition, AA inhibited <I>I</I><SUB>Ba</SUB> in a dose-dependent manner to 91.1⁑1.4, 72.0⁑3.2, 46.0⁑1.8, and 20.3⁑2.3% at 1, 5, 10, 30 mM, respectively. The inhibitory effect of AA was not affected by 10 ㄍM indomethacin, a cyclooxygenase inhibitor. Other unsaturated fatty acids, linoleic acid (LA) and oleic acid (OA) were also found to suppress <I>I</I><SUB>Ba</SUB> but stearic acid (SA), a saturated fatty acid, had no inhibitory effect on <I>I</I><SUB>Ba</SUB>. The potency sequence of these inhibitory effects was AA (79.7⁑2.3%) > LA (43.1⁑2.7%) > OA (14.2⁑1.1%) at 30 ㄍM. On superfusing the myocyte with hyposmotic solution (214 mOsm) the amplitude of <I>I</I><SUB>Ba</SUB> at 0 mV increased (38.0⁑5.5%); this increase was completely blocked by pretreatment with 30 mM AA, but not significantly inhibited by lower concentrations of AA (1, 5 and 10 ㄍM) (P>0.05). Unsaturated fatty acids shifted the steady-state inactivation curves of <I>I</I><SUB>Ba</SUB> to the left; the extent of shift caused by AA was greater than that caused by LA. The activation curve was not affected by AA or LA. The results suggest that AA and other unsaturated fatty acids directly modulate L-type calcium channels and AA might modulate the hyposmotic stretch- induced increase of L-type calcium channel current in guinea-pig gastric smooth muscle.