Dynamic response analysis of generally damped linear system with repeated eigenvalues

Yu, Rui-Fang,Zhou, Xi-Yuan,Yuan, Mei-Qiao Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4

For generally damped linear systems with repeated eigenvalues and defective eigenvectors, this study provides a decomposition method based on residue matrix, which is suitable for engineering applications. Based on this method, a hybrid approach is presented, incorporating the merits of the modal superposition method and the residue matrix decomposition method, which does not need to consider the defective characteristics of the eigenvectors corresponding to repeated eigenvalues. The method derived in this study has clear physical concepts and is easily to be understood and mastered by engineering designers. Furthermore, this study analyzes the applicability of step-by-step methods, including the Newmark beta and Runge-Kutta methods for dynamic response calculation of defective systems. Finally, the implementation procedure of the proposed hybrid approach is illustrated by analyzing numerical examples, and the correctness and the effectiveness of the formula are judged by comparing the results obtained from the different methods.

Practical coherency model suitable for near- and far-field earthquakes based on the effect of source-to-site distance on spatial variations in ground motions

Rui-fang Yu,Abduwahit Abduwaris,Yan-Xiang Yu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.6

In this study, the spatial variation mechanisms of large far-field earthquakes at engineering scales are first investigated with data from the 2008 Ms 8.0 Wenchuan earthquake. And a novel ‘coherency cut-off frequency’ is proposed to distinguish the spatial variations in ground motions in the low-frequency and high-frequency ranges. Then, a practical piecewise coherency model is developed to estimate and characterize the spatial variation in earthquake ground motions, including the effects of source-to-site distances, site conditions and neighboring topography on these variations. Four particular earthquake records from dense seismograph arrays are used to investigate values of the coherency cut-off frequency for different source-to-site distances. On the basis of this analysis, the model is established to simulate the spatial variations, whose parameters are suitable for both near- and far-field earthquake conditions. Simulations are conducted to validate the proposed model and method. The results show that compared to the existing models, the proposed model provides an effective method for simulating the spatial correlations of ground motions at local sites with known source-to-site distances.

Dynamic response analysis of generally damped linear system with repeated eigenvalues

Rui-fang Yu,Xi-yuan Zhou,Mei-qiao Yuan 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.42 No.4

For generally damped linear systems with repeated eigenvalues and defective eigenvectors, this study provides a decomposition method based on residue matrix, which is suitable for engineering applications. Based on this method, a hybrid approach is presented, incorporating the merits of the modal superposition method and the residue matrix decomposition method, which does not need to consider the defective characteristics of the eigenvectors corresponding to repeated eigenvalues. The method derived in this study has clear physical concepts and is easily to be understood and mastered by engineering designers. Furthermore, this study analyzes the applicability of step-by-step methods, including the Newmark beta and Runge-Kutta methods for dynamic response calculation of defective systems. Finally, the implementation procedure of the proposed hybrid approach is illustrated by analyzing numerical examples, and the correctness and the effectiveness of the formula are judged by comparing the results obtained from the different methods.

5,10-Methylenetetrahydrofolate Reductase Polymorphisms and Colon Cancer Risk: a Meta-analysis

Fang, Xin-Yu,Xu, Wang-Dong,Huang, Qian,Yang, Xiao-Ke,Liu, Yan-Yan,Leng, Rui-Xue,Pan, Hai-Feng,Ye, Dong-Qing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19

Previous studies investigating the association between 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and colon cancer risk have generated conflicting results. The aim of our meta-analysis was to clarify the precise association. A systematic literature search was conducted to identify all relevant studies. Pooled odds ratio (ORs) with 95% confidence interval (CI) were used to estimate the strength of the association. In this meta-analysis, a total of 13 articles, involving 5,386 cases and 8,017 controls met the inclusion criteria. Overall, a significant association was found between colon cancer risk and the MTHFR C667 polymorphism (TT vs CC+CT: OR=0.79; 95%CI=0.65-0.96; p=0.017). Stratification by ethnicity revealed that MTHFRC667 was associated with colon cancer risk in the non-Asian group (TT vs CC+CT:OR=0.77, 95%CI=0.68-0.89, p=0.000; TT vs CC: OR=0.84, 95%CI=0.73-0.97, p=0.016). Stratification by source of control indicated that MTHFR C667 also correlated with colon cancer risk in the population-based subgroup (TT vs CC: OR=0.85, 95%CI=0.74-0.97, p=0.017; TT vs CC+CT: OR=0.78, 95%CI=0.68-0.89, p=0.000) and hospital-based subgroup (TT vs CC+CT: OR=0.65, 95%CI=0.49-0.86, p=0.003). However, risk was significantly increased for MTHFR A1298C polymorphisms and colon cancer risk in hospital-based studies (C vs A: OR=1.52, 95%CI=1.26-1.83, p=0.000; CC+AC vs AA: OR=1.93, 95%CI=1.47-2.49, p=0.000) but reduced in population-based studies (CC vs AA: OR=0.83, 95%CI=0.70-0.99, p=0.042). In conclusion, the results of our meta-analysis suggest that the MTHFR C667 polymorphism is associated with reduced colon cancer risk, especially for non-Asian populations.

Gut Microbiota Community and Its Assembly Associated with Age and Diet in Chinese Centenarians

( Fang Wang ),( Ting Yu ),( Guo Hong Huang ),( Da Cai ),( Xiaolin Liang ),( Hai Yan Su ),( Zhenjun Zhu ),( Danlei Li ),( Yang Yang ),( Pei Hong Shen ),( Rui Feng Mao ),( Lian Yu ),( Mou Ming Zhao ),( 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8

Increasing evidence suggests that gut microbiota underpin the development of health and longevity. However, our understanding of what influences the composition of this community of the longevous has not been adequately described. Therefore, illumina sequencing analysis was performed on the gut microbiota of centenarians (aged 100-108 years; RC) and younger elderlies (aged 85-99 years; RE) living in Bama County, Guangxi, China and the elderlies (aged 80-92 years; CE) living in Nanning City, Guangxi, China. In addition, their diet was monitored using a semiquantitative dietary questionary (FFQ 23). The results revealed the abundance of Roseburia and Escherichia was significantly greater, whereas that of Lactobacillus, Faecalibacterium, Parabacteroides, Butyricimonas, Coprococcus, Megamonas, Mitsuokella, Sutterella, and Akkermansia was significantly less in centenarians at the genus level. Both clustering analysis and UniFraq distance analysis showed structural segregation with age and diet among the three populations. Using partial least square discriminate analysis and redundancy analysis, we identified 33 and 34 operational taxonomic units (OTUs) as key OTUs that were significantly associated with age and diet, respectively. Age-related OTUs were characterized as Ruminococcaceae, Clostridiaceae, and Lachnospiraceae, and the former two were increased in the centenarians; diet-related OTUs were classified as Bacteroidales, Lachnospiraceae, and Ruminococcaceae. The former two were deceased, whereas the later one was increased, in the high-fiber diet. The age and high-fiber diet were concomitant with changes in the gut microbiota of centenarians, suggesting that age and high-fiber diet can establish a new structurally balanced architecture of gut microbiota that may benefit the health of centenarians.

Processing, microstructure and mechanical properties of porous silicon nitride by a slip casting method using petroleum coke as pore former

Huan-Rui Wang,Ji-Qiang Gao,Fang-Li Yu,Yuan Li,Jian-Feng Yang 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6

In this study, porous Si3N4 ceramics were obtained by a slip casting method which would be easier applied in industry. The most stable and dispersing aqueous suspension was obtained from a solid slurry content of 56.2%, a carboxymethyl cellulose concentration of 0.3% as the adhesive and 0.05% glycerol as the defoamer. Petroleum coke was used as pore-former, and at the same time, it was helpful for the stability of the suspension. The burning-out of the petroleum coke seemed to be an economical way for increasing the porosity of porous Si3N4. After sintering at 1,800℃ for 2 h, samples with a pore size about 10 μm, porosities of 45-60%, and flexural strength of 52.0-112.1MPa were obtained. In this study, porous Si3N4 ceramics were obtained by a slip casting method which would be easier applied in industry. The most stable and dispersing aqueous suspension was obtained from a solid slurry content of 56.2%, a carboxymethyl cellulose concentration of 0.3% as the adhesive and 0.05% glycerol as the defoamer. Petroleum coke was used as pore-former, and at the same time, it was helpful for the stability of the suspension. The burning-out of the petroleum coke seemed to be an economical way for increasing the porosity of porous Si3N4. After sintering at 1,800℃ for 2 h, samples with a pore size about 10 μm, porosities of 45-60%, and flexural strength of 52.0-112.1MPa were obtained.

중국 허난성(河南省)의 도시화와 시민화에 대한 연구

방유옥(Fang Wei Yu),예동근(Rui Dong Gen) 한국공공사회학회 2016 공공사회연구 Vol.6 No.3

Prognostic Role of Nucleophosmin in Colorectal Carcinomas

Yang, Yu-Feng,Zhang, Xi-Ying,Yang, Mei,He, Ze-Hua,Peng, Ning-Fu,Xie, Shu-Rui,Xie, Yan-Fang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Aim: Recent research suggests that nucleophosmin (NPM) may be a prognostic marker in colorectal carcinomas (CRC). We here tested its use to predict the survival of CRC patients. Methods: We investigated NPM expression by immunohistochemistry in histologically normal to malignant colorectal tissues and evaluated its association with clinicopathological variables. Overall and disease-free survival after tumor removal were calculated by the Kaplan-Meier method, and differences in survival curves were analyzed by the log-rank test. The Cox proportional hazards model was used for multivariate analysis of prognostic factors. Results: NPM expression was found significantly upregulated in CRC compared to adjacent colorectal tissue, villous adenoma, tubular adenoma and normal colorectal mucosa (p<0.05 for all). NPM expression was statistically linked to cancer embolus, lymph node metastasis, differentiation grade, and recurrence of CRC. Overall and disease-free survival of NPM-negative CRC patients tended to be better than those for patients with NPM-positive lesions (log-rank statistic, p<0.05 for all). Multivariate analysis indicated NPM expression as an independent prognostic indicator for CRC patients (p<0.05 ). Conclusion: Our results suggest that NPM expression can predict the survival of CRC patients. Prognosis of CRC is determined by not only many known prognostic factors but also by NPM expression.

A Simplified Model for Crack Width Prediction of Flexural-Strengthened High Pre-Damaged Beams with CFRP Sheet

Feng Yu,Yuan Fang,Hao Zhou,Rui Bai,Changfeng Xie 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12

Fibre reinforced polymer (FRP) is extensively applied in the field of maintenance and reinforcement. In the actual reinforcement of concrete structures, most reinforced concrete (RC) members are in a cracked state and the existing calculation methods seldom consider the initial damage of concrete, especially the effect of severe damage on the crack of RC members. Therefore, it is necessary to propose a model for accurately evaluating the crack width of the repaired different damage state concrete members with carbon fiber reinforced plastic (CFRP) sheet. This study presents an experimental investigation on the crack behaviors of the CFRP sheet flexural-strengthened pre-damaged RC beams based on the results of an experimental program involving ten specimens. The influence of the pre-damaged level, reinforcement ratio and CFRP sheet strengthening layer on the crack development, failure characteristics, crack spacing and crack width is analyzed and discussed. Taking into account the influence of the CFRP sheet strengthening layer and pre-damaged level, a formula for predicting the average crack spacing is proposed, and then an analytical model for the crack width prediction of the flexural-strengthened high pre-damaged beams is established based on the calculation model of the crack width of the ordinary RC beams. The predicted results agree well with test values including data of this study and experimental data of 64 sets of references.

Preparation of Lysine-Coated Magnetic Fe₂O₃ Nanoparticles and Influence on Viability of A549 Lung Cancer Cells

Ma, Yu-Hua,Peng, Hai-Ying,Yang, Rui-Xia,Ni, Fang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Objective: To explore the effect of lysine-coated oxide magnetic nanoparticles (Lys@MNPs) on viability and apoptosis of A549 lung cancer cells. Methods: Transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and Zeta potentiometric analyzer were employed to characterize Lys@MNPs. Then Lys@MNPs and lung cancer A549 cells were co-cultured to study the effect of Lys@MNPs on cell viability and apoptosis. The pathway of Lys@MNPs entering A549 cells was detected by TEM and cell imaging by 1.5 T MRI. Results: Lys@MNPs were 10.2 nm in grain diameter, characterized by small size, positive charge, and superparamagnetism. Under low-dose concentration of Lys@MNPs (< $40{\mu}g/mL$), the survival rate of A549 cells was decreased but remained higher than 95% while under high-dose concentration ($100{\mu}g/mL$), the survival ratewas still higher than 80%, which suggested Lys@MNPs had limited influence on the viability of A549 cells, with good biocompatibility and and no induction of apoptosis. Moreover, high affinity for cytomembranes, was demonstrated presenting good imaging effects. Conclusion: Lys@MNPs can be regarded as a good MRI negative contrast agents, with promising prospects in biomedicine.