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Daniel Hagan and Martin Hagan

Abstract

In this paper, we describe how several soft computing tools can be used to assist in high throughput screening of potential drug candidates. Individual small molecules (ligands) are assessed for their potential to bind to specific proteins (receptors). Committees of multilayer networks are used to classify protein-ligand complexes as good binders or bad binders, based on selected chemical descriptors. The novel aspects of this paper include the use of statistical analyses on the weights of single layer networks to select the appropriate descriptors, the use of Monte Carlo cross-validation to provide confidence measures of network performance (and also to identify problems in the data), the addition of new chemical descriptors to improve network accuracy, and the use of Self Organizing Maps to analyze the performance of the trained network and identify anomalies. We demonstrate the procedures on a large practical data set, and use them to discover a promising characteristic of the data. We also perform virtual screenings with the trained networks on a number of benchmark sets and analyze the results.

Open access

Melissa Hagan Hughes, Kyle F. Lott and J. Daniel Heck

SUMMARY

Menthol has been measured in cigarettes, in cigarette smoke preparations, and in smokers' blood and urine, but the efficiency of retention of smoke-delivered menthol by the smoker has not previously been reported. Thirteen smokers participated in a study designed to determine the deposition and retention efficiency of menthol in cigarette smoke in the respiratory tract when smoking mentholated cigarettes. This paper describes the results obtained during the measurement of analytes in exhaled cigarette smoke. Solanesol, nicotine, and menthol in exhaled smoke were collected using a vacuum-assisted pump during the smoking session in which each participant smoked three mentholated cigarettes within one hour. The analytes were quantified using a high-performance liquid chromatography (HPLC) method for solanesol and a gas chromatography- flame ionization detection (GC-FID) method for nicotine and menthol. Cigarette butts were collected after smoking and compared against those from machinesmoked cigarettes to provide an estimate of mouth-level exposures to the smoke constituents during normal smoking. An average of 93% of smoke-delivered menthol, 97% of nicotine and 64% of solanesol was retained by smokers of a mentholated cigarette. The results for solanesol and nicotine in this study were in agreement with prior published values for smokers of non-mentholated cigarettes. The findings of this study confirm the general utility of the mouth-level exposure technique to estimate smokers' exposures to mainstream smoke constituents, and are consistent with a considerable body of evidence from investigations of cigarette smoke exposure biomarkers indicating that exposures of smokers to major smoke constituents from menthol and non-menthol cigarettes are essentially identical. [Beitr. Tabakforsch. Int. 26 (2014) 26-33]