INTRODUCTION The purpose of this study was to quantify tooth movement among different retention protocols after the orthodontic appliances were removed. METHODS A total of 90 patients were evaluated using the American Board of Orthodontics discrepancy index and the cast and radiograph evaluation at debond and the 1-year recall. These patients were equally divided into 3 retention protocols: u...

In this work, novel atom-type-based topological indices, named AT indices, were presented as descriptors to encode structural information of a molecule at the atomic level. The descriptors were successfully used for simultaneous quantitative structure-retention relationship (QSRR) modeling of saturated alcohols on different stationary phases (SE-30, OV-3, OV-7, OV-11, OV-17 and OV-25). At first...

This paper reports mass spectra and linear temperature programmed retention indices (I(T)) for 31 esters of mono- and sesquiterpene alcohols with hydroxycinnamic acids. In this study, 14 phenylpropenoids were synthesized by esterification of terpenols with p-coumaric, ferulic, caffeic and sinapinic acids. Other phenylpropenoids were semi-quantitatively isolated by column chromatography from exu...

Gene Expression Programming (GEP) is a novel genetic algorithm, a highly effective, stable random searching method. We take GEP to make models of Quantitative Structure-Retention Relationship (QSRR) for a series of oxygen-containing organic compounds of GC retention index, and compare the predictive results with Artificial Neural Network (ANN) and Multiple Linear Regression (MLR). The correlati...