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Determination of flutter derivatives by stochastic subspace identification technique
Qin, Xian-Rong,Gu, Ming Techno-Press 2004 Wind and Structures, An International Journal (WAS Vol.7 No.3
Flutter derivatives provide the basis of predicting the critical wind speed in flutter and buffeting analysis of long-span cable-supported bridges. In this paper, one popular stochastic system identification technique, covariance-driven Stochastic Subspace Identification(SSI in short), is firstly presented for estimation of the flutter derivatives of bridge decks from their random responses in turbulent flow. Secondly, wind tunnel tests of a streamlined thin plate model and a ${\Pi}$ type blunt bridge section model are conducted in turbulent flow and the flutter derivatives are determined by SSI. The flutter derivatives of the thin plate model identified by SSI are very comparable to those identified by the unifying least-square method and Theodorson's theoretical values. As to the ${\Pi}$ type section model, the effect of turbulence on aerodynamic damping seems to be somewhat notable, therefore perhaps the wind tunnel tests for flutter derivative estimation of those models with similar blunt sections should be conducted in turbulent flow.
Expression and Functional Role of ALDH1 in Cervical Carcinoma Cells
Rao, Qun-Xian,Yao, Ting-Ting,Zhang, Bing-Zhong,Lin, Rong-Chun,Chen, Zhi-Liao,Zhou, Hui,Wang, Li-Juan,Lu, Huai-Wu,Chen, Qin,Di, Na,Lin, Zhong-Qiu Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4
Tumor formation and growth is dictated by a very small number of tumor cells, called cancer stem cells, which are capable of self-renewal. The genesis of cancer stem cells and their resistance to conventional chemotherapy and radiotherapy via mechanisms such as multidrug resistance, quiescence, enhanced DNA repair abilities and anti-apoptotic mechanisms, make it imperative to develop methods to identify and use these cells as diagnostic or therapeutic targets. Aldehyde dehydrogenase 1 (ALDH1) is used as a cancer stem cell marker. In this study, we evaluated ALDH1 expression in CaSki, HeLa and SiHa cervical cancer cells using the Aldefluor method to isolate ALDH1-positive cells. We showed that higher ALDH1 expression correlated with significantly higher rates of cell proliferation, microsphere formation and migration. We also could demonstrate that SiHa-ALDH1-positive cells were significantly more tumorigenic compared to SiHa-ALDH1-negative cells. Similarly, SiHa cells overexpressing ALDH1 were significantly more tumorigenic and showed higher rates of cell proliferation and migration compared to SiHa cells where ALDH1 expression was knocked down using a lentivirus vector. Our data suggested that ALDH1 is a marker of cervical cancer stem cells and expand our understanding of its functional role.
Peng Zhu,An-Qin Duan,Ting-Xian Deng,Xing-Rong Lu,Xiao-Ya Ma,Sha-Sha Liang,Chun-Ying Pang,Xian-Wei Liang 한국생물공학회 2017 Biotechnology and Bioprocess Engineering Vol.22 No.5
In recent years, CRISPR/Cas9 has rapidly become one of the most promising genome editing tools because it is simple and easy to use and cost effective. However, the large size of Cas9 sequences limits its application in clinically promising vectors and it also impacts non-viral transfection. In this study, CRISPR/Cas9 adenovirus vectors that target the buffalo 18s rDNA gene were constructed, transfected into 293 cells for adenovirus packaging, and the adenovirus was used to knockout the 18s rDNA gene in buffalo mammary epithelial cells. The results demonstrated that the CRISPR/Cas9 adenovirus vectors for the buffalo 18s rDNA gene could efficiently target the sites as revealed by the fluorescence reporter system. After amplification, the adenovirus titer of Sn458- 18s1 and Sn458-18s2 reached 1.03 × 109PFU/mL and 1.05 × 109 PFU/mL, respectively. For buffalo mammary epithelial cell infection, the efficiency was 100% when the multiplicity of infection (MOI) 100 PFU/mL. There were 9 mutational clones found in the 20 clones, and the gene mutagenesis rate reached 45%. Of these, 2 clones were 35-bp deleted and 7 clones were 12-bp deleted. These results suggested that the adenovirus system overcame the low transfection efficiency of the buffalo mammary epithelial cells associated with using lipid-based methods or electroporation. Moreover, we preliminary developed an efficient technique for multiple-locus gene targeting at repeated sequences of the buffalo genome.
Yuantao Sun,Zengzeng Zhang,Qing Zhang,Xian-rong Qin,Lifu Luo 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10
The fatigue failure of crack structure is influenced by fracture failure and static strength failure in the process of its growth. And the correlation characteristics between them change with the crack growth, which brings difficulties to safety assessment. To solve this problem, we propose a reliability model of failure crack propagation (FCP) based on time-varying copula. Meanwhile, a dynamic parameter estimation is put forward to build the time-varying copula. First, a flexible mixed copula model was constructed, by means of linear weighted model, to describe the nonlinear dependence among failure modes. Then the time-varying correlation parameters of copula were obtained by maximum likelihood estimation and least square polynomial fitting. Therefore, the dynamic parameter estimation of copula was realized, and then we used the built time-varying copula model to solve the reliability of joint failure. Finally, a numerical example was provided to illustrate the feasibility and application of the built time-varying copula model.
Research on reliability analytical method of complex system based on CBN model
Yuantao Sun,Kaige Chen,Chao Liu,Qing Zhang,Xian-rong Qin 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1
Considering that there are often many variables correlated to each other in complex system, copula functions are introduced into reliability analysis. While with the increase of variables, the dimension of copula function will be high. For the above problems, Bayesian network (BN) is introduced into reliability analysis and a copula Bayesian network (CBN) model is proposed. Taking driving system of new rail mounted container gantry (NRMG) as an example, Gaussian copula and t-copula are used and compared in the process of generating correlation data. Additionally, in order to construct local copula function between parent and descendent nodes, Gumbel and Clayton copulas are compared based on Akaike information criterion. Finally, the reliability inference based on CBN model is performed. Compared with BN model, the rationality of CBN model is verified, and the results show that the reliability calculated by CBN model is smaller, which will put forward higher requirements for the driving system.
Zhao, Fang-Hui,Tiggelaar, Sarah M.,Hu, Shang-Ying,Zhao, Na,Hong, Ying,Niyazi, Mayinuer,Gao, Xiao-Hong,Ju, Li-Rong,Zhang, Li-Qin,Feng, Xiang-Xian,Duan, Xian-Zhi,Song, Xiu-Ling,Wang, Jing,Yang, Yun,Li, Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5
Objectives: To assess knowledge of HPV and attitudes towards HPV vaccination among the general female population, government officials, and healthcare providers in China to assist the development of an effective national HPV vaccination program. Methods: A cross-sectional epidemiologic survey was conducted across 21 urban and rural sites in China using a short questionnaire. 763 government officials, 760 healthcare providers, and 11,681 women aged 15-59 years were included in the final analysis. Data were analyzed using standard descriptive statistics and logistic regression. Results: Knowledge of HPV among the general female population was low; only 24% had heard of HPV. Less than 20% of healthcare providers recognized sexually na$\ddot{i}$ve women as the most appropriate population for HPV vaccination. There was high acceptance of the HPV vaccine for all categories of respondents. Only 6% of women were willing to pay more than US $300 for the vaccine. Conclusions: Aggressive education is necessary to increase knowledge of HPV and its vaccine. Further proof of vaccine safety and efficacy and government subsidies combined with increased awareness could facilitate development and implementation of HPV vaccination in China.