Atoms in most organic molecules are often carbon,oxygen,nitrogen,sulfur,halogens,etc. Based on the three-dimensional structure of a molecule,a molecular structural characterization（MSC） method called improved molecu...Atoms in most organic molecules are often carbon,oxygen,nitrogen,sulfur,halogens,etc. Based on the three-dimensional structure of a molecule,a molecular structural characterization（MSC） method called improved molecular electronegativity-distance vector（I-MEDV） was developed. It was used to describe the structures of 37 compounds of styrax japonicus sieb flowers. Through multiple linear regression（MLR）,a QSRR model was built up. The correlation coefficient（R1） of the model was 0.980. Then,4 vectors were selected to build another model through the method of stepwise multiple regression（SMR） ,and the correlation coefficient（R2） of the model was 0.975. Moreover,all the two models were evaluated by performing the crossvalidation with the leave-one-out（LOO） procedure and the correlation coefficients（Rcv） were 0.948 and 0.968,respectively. The results show that the I-MEDV could successfully describe the structures of organic compounds. The stability and predictability of the models were good.展开更多
将食用植物油中的脂肪酸转化为相应的脂肪酸甲酯,并采用立体结构参数Steric and Electronic Descriptors(SEDs)表征其分子结构,然后运用多元线性回归(MLR)方法,建立了预测食用植物油中脂肪酸(甲酯)的定量结构-色谱保留相关(QSRR)模型,...将食用植物油中的脂肪酸转化为相应的脂肪酸甲酯,并采用立体结构参数Steric and Electronic Descriptors(SEDs)表征其分子结构,然后运用多元线性回归(MLR)方法,建立了预测食用植物油中脂肪酸(甲酯)的定量结构-色谱保留相关(QSRR)模型,同时采用内部及外部双重验证的方法对所建模型的稳定性能和预测能力进行了分析和验证。建模计算值、留一法(LOO)交互检验(CV)预测值和外部样本预测值的相关系数R、R LOO、Q2ext分别为0.9990、0.9970、0.9860。结果表明,SEDs参数能较好地表征食用植物油中的脂肪酸甲酯分子的结构信息,所建立的QSRR模型具有良好的稳定性和预测能力,为间接分析鉴定食用植物油中脂肪酸提供了一种方便有效的新途径。展开更多
综述了QSRR中的多元线性回归(Multple Linear Regresion,MLR)、偏最小二乘回归(Partial Least Squares Regression,PLSR)、人工神经网络(Artificial Neural Networks,ANN)三种常用建模方法、分子描述符的选取的要点及原则及相关模型的...综述了QSRR中的多元线性回归(Multple Linear Regresion,MLR)、偏最小二乘回归(Partial Least Squares Regression,PLSR)、人工神经网络(Artificial Neural Networks,ANN)三种常用建模方法、分子描述符的选取的要点及原则及相关模型的建立和评价等方法在食品分析中的应用现状,并对QSRR在该领域的研究方向和发展前景进行了展望,以期为今后更深层次的研究作综合性的参考。展开更多
基金supported by the Youth Foundation of Education Bureau,Sichuan Province (09ZB036)Technology Bureau,Sichuan Province (2006j13-141)
文摘Atoms in most organic molecules are often carbon,oxygen,nitrogen,sulfur,halogens,etc. Based on the three-dimensional structure of a molecule,a molecular structural characterization（MSC） method called improved molecular electronegativity-distance vector（I-MEDV） was developed. It was used to describe the structures of 37 compounds of styrax japonicus sieb flowers. Through multiple linear regression（MLR）,a QSRR model was built up. The correlation coefficient（R1） of the model was 0.980. Then,4 vectors were selected to build another model through the method of stepwise multiple regression（SMR） ,and the correlation coefficient（R2） of the model was 0.975. Moreover,all the two models were evaluated by performing the crossvalidation with the leave-one-out（LOO） procedure and the correlation coefficients（Rcv） were 0.948 and 0.968,respectively. The results show that the I-MEDV could successfully describe the structures of organic compounds. The stability and predictability of the models were good.
文摘将食用植物油中的脂肪酸转化为相应的脂肪酸甲酯,并采用立体结构参数Steric and Electronic Descriptors(SEDs)表征其分子结构,然后运用多元线性回归(MLR)方法,建立了预测食用植物油中脂肪酸(甲酯)的定量结构-色谱保留相关(QSRR)模型,同时采用内部及外部双重验证的方法对所建模型的稳定性能和预测能力进行了分析和验证。建模计算值、留一法(LOO)交互检验(CV)预测值和外部样本预测值的相关系数R、R LOO、Q2ext分别为0.9990、0.9970、0.9860。结果表明,SEDs参数能较好地表征食用植物油中的脂肪酸甲酯分子的结构信息,所建立的QSRR模型具有良好的稳定性和预测能力,为间接分析鉴定食用植物油中脂肪酸提供了一种方便有效的新途径。
文摘综述了QSRR中的多元线性回归(Multple Linear Regresion,MLR)、偏最小二乘回归(Partial Least Squares Regression,PLSR)、人工神经网络(Artificial Neural Networks,ANN)三种常用建模方法、分子描述符的选取的要点及原则及相关模型的建立和评价等方法在食品分析中的应用现状,并对QSRR在该领域的研究方向和发展前景进行了展望,以期为今后更深层次的研究作综合性的参考。
