Background Bone morphogenetic protein （BMP）-2, alkaline phosphatase （ALP）, and collagen type I are known to play a critical role in the process of bone remodeling. However, the relationship between mechanical stra...Background Bone morphogenetic protein （BMP）-2, alkaline phosphatase （ALP）, and collagen type I are known to play a critical role in the process of bone remodeling. However, the relationship between mechanical strain and the expression of BMP-2, ALP, and COL-I in osteoblasts was still unknown. The purpose of this study was to investigate the effects of different magnitudes of mechanical strain on osteoblast morphology and on the expression of BMP-2, ALP, and COL-I. Methods Osteoblast-like cells were flexed at four deformation rates （0, 6%, 12%, and 18% elongation）. The expression of BMP-2 mRNA, ALP, and COL-I in osteoblast-like cells were determined by real-time quantitative reverse transcription polymerase chain reaction, respectively. The results were subjected to analysis of variance （ANOVA） using SPSS 13.0 statistical software. Results The cells changed to fusiform and grew in the direction of the applied strain after the mechanical strain was loaded. Expression level of the BMP-2, ALP, and COL-I increased magnitude-dependently with mechanical loading in the experimental groups, and the 12% elongation group had the highest expression （P 〈0.05）. Conclusion Mechanical strain can induce morphological change and a magnitude-dependent increase in the expression of BMP-2, ALP, and COL-I mRNA in osteoblast-like cells, which might influence bone remodeling in orthodontic treatment.展开更多
To solve the topology optimization of complicated multi-objective continuous/discrete design variables in aircmit structure design, a Parallel Pareto Genetic Algorithm （PPGA） is presented based on grid platform in t...To solve the topology optimization of complicated multi-objective continuous/discrete design variables in aircmit structure design, a Parallel Pareto Genetic Algorithm （PPGA） is presented based on grid platform in this paper. In the algorithm, the commercial finite element analysis （FEA） software is integrated as the calculating tool for analyzing the objective functions and the filter of Pareto solution set based on weight information is introduced to deal with the relationships among all objectives. Grid technology is utilized in PPGA to realize the distributed computations and the user interface is developed to realize the job submission and job management locally/remotely. Taking the aero-elastic tailoring of a composite wing for optimization as an example, a set of Pareto solutions are obtained for the decision-maker. The numerical results show that the aileron reversal problem can be solved by adding the limited skin weight in this system. The algorithm can be used to solve complicated topology optimization for composite structures in engineering and the computation efficiency can be improved greatly by using the grid platform that aggregates numerous idle resources.展开更多
Least Absolute Shrinkage and Selection Operator (LASSO) is used for variable selection as well as for handling the multicollinearity problem simultaneously in the linear regression model. LASSO produces estimates havi...Least Absolute Shrinkage and Selection Operator (LASSO) is used for variable selection as well as for handling the multicollinearity problem simultaneously in the linear regression model. LASSO produces estimates having high variance if the number of predictors is higher than the number of observations and if high multicollinearity exists among the predictor variables. To handle this problem, Elastic Net (ENet) estimator was introduced by combining LASSO and Ridge estimator (RE). The solutions of LASSO and ENet have been obtained using Least Angle Regression (LARS) and LARS-EN algorithms, respectively. In this article, we proposed an alternative algorithm to overcome the issues in LASSO that can be combined LASSO with other exiting biased estimators namely Almost Unbiased Ridge Estimator (AURE), Liu Estimator (LE), Almost Unbiased Liu Estimator (AULE), Principal Component Regression Estimator (PCRE), r-k class estimator and r-d class estimator. Further, we examine the performance of the proposed algorithm using a Monte-Carlo simulation study and real-world examples. The results showed that the LARS-rk and LARS-rd algorithms,?which are combined LASSO with r-k class estimator and r-d class estimator,?outperformed other algorithms under the moderated and severe multicollinearity.展开更多
2015年6月9日,2015 e Net16论坛在北京798艺术区尤伦斯当代艺术中心举行。来自母婴、生鲜电商、在线教育、数字营销、云计算等互联网热门创新领域的十五家成长型企业代表、以及部分业内专家围绕＂电商如何联接家庭厨房＂、＂寻找家庭服...2015年6月9日,2015 e Net16论坛在北京798艺术区尤伦斯当代艺术中心举行。来自母婴、生鲜电商、在线教育、数字营销、云计算等互联网热门创新领域的十五家成长型企业代表、以及部分业内专家围绕＂电商如何联接家庭厨房＂、＂寻找家庭服务产业的风口＂、＂从蛮荒到文明,在线教育的品牌成长之路＂三轮主题对话交流,就2015上半年互联网行业的整体发展和显著特点进行了深入的探讨和总结,阐述了各自企业的价值主张。展开更多
文摘Background Bone morphogenetic protein （BMP）-2, alkaline phosphatase （ALP）, and collagen type I are known to play a critical role in the process of bone remodeling. However, the relationship between mechanical strain and the expression of BMP-2, ALP, and COL-I in osteoblasts was still unknown. The purpose of this study was to investigate the effects of different magnitudes of mechanical strain on osteoblast morphology and on the expression of BMP-2, ALP, and COL-I. Methods Osteoblast-like cells were flexed at four deformation rates （0, 6%, 12%, and 18% elongation）. The expression of BMP-2 mRNA, ALP, and COL-I in osteoblast-like cells were determined by real-time quantitative reverse transcription polymerase chain reaction, respectively. The results were subjected to analysis of variance （ANOVA） using SPSS 13.0 statistical software. Results The cells changed to fusiform and grew in the direction of the applied strain after the mechanical strain was loaded. Expression level of the BMP-2, ALP, and COL-I increased magnitude-dependently with mechanical loading in the experimental groups, and the 12% elongation group had the highest expression （P 〈0.05）. Conclusion Mechanical strain can induce morphological change and a magnitude-dependent increase in the expression of BMP-2, ALP, and COL-I mRNA in osteoblast-like cells, which might influence bone remodeling in orthodontic treatment.
文摘To solve the topology optimization of complicated multi-objective continuous/discrete design variables in aircmit structure design, a Parallel Pareto Genetic Algorithm （PPGA） is presented based on grid platform in this paper. In the algorithm, the commercial finite element analysis （FEA） software is integrated as the calculating tool for analyzing the objective functions and the filter of Pareto solution set based on weight information is introduced to deal with the relationships among all objectives. Grid technology is utilized in PPGA to realize the distributed computations and the user interface is developed to realize the job submission and job management locally/remotely. Taking the aero-elastic tailoring of a composite wing for optimization as an example, a set of Pareto solutions are obtained for the decision-maker. The numerical results show that the aileron reversal problem can be solved by adding the limited skin weight in this system. The algorithm can be used to solve complicated topology optimization for composite structures in engineering and the computation efficiency can be improved greatly by using the grid platform that aggregates numerous idle resources.
文摘Least Absolute Shrinkage and Selection Operator (LASSO) is used for variable selection as well as for handling the multicollinearity problem simultaneously in the linear regression model. LASSO produces estimates having high variance if the number of predictors is higher than the number of observations and if high multicollinearity exists among the predictor variables. To handle this problem, Elastic Net (ENet) estimator was introduced by combining LASSO and Ridge estimator (RE). The solutions of LASSO and ENet have been obtained using Least Angle Regression (LARS) and LARS-EN algorithms, respectively. In this article, we proposed an alternative algorithm to overcome the issues in LASSO that can be combined LASSO with other exiting biased estimators namely Almost Unbiased Ridge Estimator (AURE), Liu Estimator (LE), Almost Unbiased Liu Estimator (AULE), Principal Component Regression Estimator (PCRE), r-k class estimator and r-d class estimator. Further, we examine the performance of the proposed algorithm using a Monte-Carlo simulation study and real-world examples. The results showed that the LARS-rk and LARS-rd algorithms,?which are combined LASSO with r-k class estimator and r-d class estimator,?outperformed other algorithms under the moderated and severe multicollinearity.
文摘2015年6月9日,2015 e Net16论坛在北京798艺术区尤伦斯当代艺术中心举行。来自母婴、生鲜电商、在线教育、数字营销、云计算等互联网热门创新领域的十五家成长型企业代表、以及部分业内专家围绕＂电商如何联接家庭厨房＂、＂寻找家庭服务产业的风口＂、＂从蛮荒到文明,在线教育的品牌成长之路＂三轮主题对话交流,就2015上半年互联网行业的整体发展和显著特点进行了深入的探讨和总结,阐述了各自企业的价值主张。
