A two-dimensional retention index system for fatty acid methyl esters (2D-FARI) is proposed. The system is based on the application of different temperature and pressure programs on a single capillary column. A calibration sample is analysed and the retention data is calibrated against a set of reference 2D-FARI values. The calibration models are then applied to predict the 2D-FARI values for c...

In the present work, an artificial neural network (ANN) model was used to study the quantitative structure retention relationship (QSRR) of retention index (RI) of some volatile compounds in natural cocoa and conched chocolate powder. Molecular structural descriptors are selected using genetic algorithm to construct the nonlinear QSRR models, kernel partial least squares PLS (KPLS) and Levenber...

A method was developed to calculate the second dimension retention index of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC/TOF-MS) data using n-alkanes as reference compounds. The retention times of the C(7)-C(31) alkanes acquired during 24 isothermal experiments cover the 0-6s retention time area in the second dimension retention time space, which make...

abstract different definitions have been proposed for soil quality. various soil properties have been suggetsted as soil quality indices by researchers. this research was conducted to study the relationship between slope of retention curve at its inflection point (s index) and other soil physical quality indices, because the reserches between s index and soil physical properties are little. thi...

UNLABELLED The purpose of this study was to determine whether 201Tl retention in focal intracranial lesions can help distinguish central nervous system (CNS) lymphoma from toxoplasmosis and other nonmalignant CNS lesions in patients with acquired immunodeficiency syndrome. METHODS Forty-nine patients who presented with focal lesions on CT and/or MRI had 201Tl brain SPECT studies (early and de...

This article presents case base maintenance policies for case index revision and case retention The policies are formulated in the context of case based planners performing case adaptation by derivational replay We implemented these policies on a particular case based planner and claim that our case index revision policy improves the accuracy of the retrieval and that the case retention policy ...

In order to obtain the soil water retention curve of an unsaturated soil which is defined as the relationship between water content and suction, extensive laboratory tests are essential. These laboratory tests are usually costly and time consuming. Moreover, for most practical problems, it has been found that approximate unsaturated soil properties are adequate for analysis. Thus, empirical pro...