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Copyright of Biotechnology Bulletin is the property of Biotechnology Bulletin Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biotechnology Bulletin is the property of Biotechnology Bulletin Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shanxi Agricultural Sciences is the property of Shanxi Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of National Chiayi University Journal of Educational Research is the property of National Chiayi University, Department of Education and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biotechnology Bulletin is the property of Biotechnology Bulletin Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quantitative structure-property relationship (QSPR) method is performed to study the relationship between Pka values and molecular descriptors of 34 sorts of substituted carboxylic acids. With the DRAGON 5.4 software and HyerChem 7, 568 structural parameters and 12 quantum chemistry parameters for 34 sorts of substituted carboxylic acids are calculated. 61 structural descriptors are chosen by using the variable selection method of weighted deviation. Through stepwise regress, a equation of QSAR of 34 sorts of substituted carboxylic acids has been successfully proposed. The R (correlation) and S (standard error) are 0.990 and 0.170, respectively. Furthermore, the two-sided t-test was used to validate the significance of the 6 descriptors. With the statistically significance (<0.05), correlation coefficients of descriptors show that the 6 descriptors have important impaction the pKa values. Furthermore, leave-one-out cross validation as performed, the results confirmed the good stability and powerful prediction of this model. The physical meaning and the influence of the 6 parameters on pKa of substituted carboxylic acids were investigated. The two parameters, net charge of the hydrogen atoms in carboxyl (QH) and net charge of the oxygen atom in non-hydroxyl (Q=O) are the key factors affecting the acid intensity of substituted carboxylic acids. [ABSTRACT FROM AUTHOR]