Chemometrics & Informatics / Ezine
Calculating spectra: quantum insights into Raman
Date: Oct 15, 2011
Author: David Bradley
The first calculations of Raman optical activity spectra using coupled-cluster theory - one of the most reliable quantum chemical methods available - have been used to provide new insights into the scattering of polarized light from chiral molecules.
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Journal Highlight: Characterisation of Slovenian honeys on the basis of sensory and physicochemical analysis with a chemometric approach
Date: Sep 20, 2011
Author:
The purpose of this study was sensory and physicochemical characterisation of Slovenian honeys with a chemometric approach. Honey samples were obtained from the beekeepers in different natural geographical macroregions of Slovenia. The sensory characteristics of the seven main types of Slovenian honeys are described, together with the physicochemical analyses.
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Algorithmic cancer diagnosis: Raman spectra reveal pre-cancer
Date: Sep 15, 2011
Author: David Bradley
A genetic algorithm can be applied to Raman spectra for the rapid, in vivo identification of pre-cancerous tissues in the cervix, according to work recently published in The Analyst.
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Journal Highlight: OnPLS - a novel multiblock method for the modelling of predictive and orthogonal variation
Date: Aug 30, 2011
Author:
OnPLS is a novel multiblock analysis method that is equivalent to O2PLS in cases with two matrices, but which generalises symmetrically to cases involving more than two matrices. The method's utility was demonstrated by its application to three synthetic data sets. It was shown that OnPLS affords a reduced number of globally predictive components and increased intercorrelations of scores, and that it greatly facilitates interpretation of the predictive model.
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Red, red, red wine: A touch too much anthocyanin?
Date: Aug 15, 2011
Author: David Bradley
Various approaches to statistical analysis of spectroscopic data can reveal whether red wine has been adulterated with anthocyanins to artificially improve, or "correct", its red colour.
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Journal Highlight: Predictive power of LDA to discriminate abnormal wine fermentations
Date: Jul 19, 2011
Author:
Predictive power of Stepwise Linear Discriminant Analysis (SLDA) was evaluated to discriminate the behavior of wine fermentation. Information of different chemical concentrations from industrial wine fermentations was used. Procedure consisted of non linear curve fitting and SLDA applied to the parameters of the curve. The correlation coefficient of alcoholic degree, initial concentration of glucose, initial density and correlation coefficient of tartaric acid were the variables more discriminant and they...
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Open source laboratory data: Small-scale management
Date: Jul 15, 2011
Author: David Bradley
The management of chemical structures in a small laboratory is an important and often tedious daily task. Proprietary software is costly and by definition closed, but an open source modifiable and redistributable application, MyMolDB, described in the Journal of Computational Chemistry could make life easier for small lab managers.
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Journal Highlight: Comparison of novel sensory panel performance evaluation techniques with e-nose analysis integration
Date: Jun 30, 2011
Author:
A complex approach was used to evaluate the performance of a sensory panel with two novel techniques: GCAP (Gravity Center Area/Perimeter) and CRRN (Compare Ranks with Random Numbers). Profile analysis was performed on Sri Lanka black tea batches from different plantations; for the prediction of sensory data from electronic nose results partial least square regression and support vector machine regression were used. Prediction by support vector machine gave close correlation between the results of...
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Healthier skin: It's in the trees
Date: Jun 15, 2011
Author: David Bradley
Antioxidants are popular as so-called anti-aging ingredients in skin creams. Now, an analysis of HPLC, MS, NMR and assay data reveals how these healthful substances might be present in the leaf buds of poplar trees.
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Journal Highlight: Quantification of magnetic resonance spectroscopy signals with lineshape estimation
Date: May 24, 2011
Author:
Quantification of MRS signals is required for providing metabolite concentrations of the tissue under investigation. However, inhomogeneities of the static magnetic field and tissue heterogeneities affect the lineshape of MRS signals and thus quantification. We propose an extension of the self-deconvolution method, by estimating and smoothing a common lineshape using a robust method with local regression.
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