Feature selection aims to remove irrelevant and redundant features from input data. For gene expression, selecting important genes from gene expression data is essential since the gene expression data often consists of a large number of genes. However, the commonly-used feature selection methods are usually biased toward the highest rank features, and the correlation of these selected features may be high. To overcome these problems, we propose an informative feature clustering and selection method to select informative and diverse genes from the gene expression data. The method consists of two steps. In the first step, a feature clustering (FC) method is designed to cluster total genes into several gene clusters. In FC, a set of feature weights are computed to respect the importance of each gene, and we sort the genes in different gene clusters based on the feature weights. In the second step, we propose a stratified feature selection (SFS) method to select genes from different gene clusters and combine them to form the final feature set. Experiments on several gene expression data demonstrate the superiority of the proposed method over six popular feature selection methods.

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The transformation mechanism and kinetics of 2‐chloro‐1,1,2‐trifluoroethyl‐difluoromethyl‐ether (CTDE, CHF2OCF2CHFCl) triggered by OH radicals are studied by density‐functional theory methods and canonical variational transition state theory. The computational rate constant including small‐curvature tunneling correction is found to be in commendable agreement with the experimental data. Two hydrogen abstraction channels to form the alkyl radicals of C·F2OCF2CHFCl and CHF2OCF2C·FCl are observed, and the formation of CHF2OCF2C·FCl is found to be more favorable than C·F2OCF2CHFCl kinetically and thermodynamically. Subsequent evolution of CHF2OCF2C·FCl in the presence of NO and O2 indicates that the organic nitrate (CHF2OCF2CONO2FCl) is the stable product. The dechlorinate of alkoxy radical (CHF2OCF2C(O·)FCl) is the most favorable degradation channel, and the estimated ozone depletion potential for CTDE relative to chlorofluorocarbon‐11 is 0.0204, which could lead to ozone depletion as a consequence. The computed atmospheric lifetime for CTDE is found to be 3.69 years by considering the combined contributions from OH radicals and Cl atoms. The total radiative forcing and global warming potential of CTDE are, respectively, 0.547 W m−2 ppbv and 628.58 (100 years) at 298 K, suggesting that the contribution of CTDE to the greenhouse effect is moderate.

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