Shape-matching techniques

J., Zheng, W. (2008) Novel approach to structure-based pharmacophore search using computational geometry and shape matching techniques. / Chem Inf Model 48, 889-901. 

Increased computational resources allow the widespread application of fundamental kinetic models. Relumped single-event microkinetics constitute a subtle methodology matching present day s analytical techniques with the computational resources. The singleevent kinetic parameters are feedstock invariant. Current efforts are aimed at mapping catal) t properties such as acidity and shape selectivity. The use of fundamental kinetic models increases the reliability of extrapolations from laboratory or pilot plant data to industrial reactor simulation. 

In matched-mold forming, a heated sheet is placed between a matched female and male mold parts. As the two mold halves close, they distort the sheet to their shape. The air between the mold halves is removed. The article walls are more uniform than for many of the thermoforming techniques. This technique is used for the production of foamed PS and foamed polyolefins food containers. 

Further, in atomic spectrometry we must face the serious problem that the behaviour (atomisation/excitation characteristics) of the analyte in the calibration samples should be the same as in the future unknown samples where the analyte of interest has to be quantified, otherwise peak displacement and changes of the peak shape may cause serious bias in the predictions. Fortunately, many atomic techniques analyse aqueous extracts or acid solutions of the (pretreated) samples and current working procedures match the amount of acids in the calibration and treated samples, so the matrices become rather similar. Current practices in method development involve studying potential interferents. The analyte is fixed at some average concentration (sometimes studies are made at different concentrations) and the effects of a wide number of potential interferents are tested. They include major cations, anions and... 

It must be emphasized that visual matching of the densities tends to give a measure of the peak rather than the integrated intensity. Only when the spots are all of the same size and shape can one obtain fairly reliable integrated intensities. Though no longer used for obtaining data for structure determinations, the technique is still used in routine identification. 

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