Detection of malignant tumours by multivariate analysis of proton magnetic resonance spectra of serum

Pretreatment of Mass Spectral Profiles: Application to Proteomic Data

“…The reduction in signal intensity accompanying the n th root transform also impacts regions with intensity close to noise level, and this may lead to loss of information for such regions. In such cases, it may be convenient to do a normalization and local PCA just on these regions without the n th root transform since without the presence of high-intensity regions, normalization of data is less influenced by heteroscedastic noise …”

Pretreatment of Mass Spectral Profiles: Application to Proteomic Data

“…The reduction in signal intensity accompanying the n th root transform also impacts regions with intensity close to noise level, and this may lead to loss of information for such regions. In such cases, it may be convenient to do a normalization and local PCA just on these regions without the n th root transform since without the presence of high-intensity regions, normalization of data is less influenced by heteroscedastic noise …”

Quantification of plasma lipids and apolipoproteins by use of proton NMR spectroscopy, multivariate and neural network analysis

“…It has earlier been reported that shifting of just a few points of the lactate peaks from spectra to spectra might be fatal for PCA of 1 H NMR spectra of blood plasma. 64 Leaving out the lactate peaks from the spectra in our X-matrix caused no differences in calibration (results not shown). The reason for this is probably based on both that the chemical shift of the lactate peaks in our spectra is relatively constant, and that the variation in lactate signal amplitude (concentration) is not systematic.…”

Mrs-based Metabolomics in Cancer Research

“…1,2 Another frequently used method is principal component analysis, widely used in chemical and biological sciences. 3 Once the critically sensitive spectral components have been identified, a method to quantify this sensitivity is necessary. One commonly used method is partial least squares discriminant analysis (PLS-DA), where assessment of goodness of fit is taken to indicate the accuracy of the method.…”

“…1,2 Another frequently used method is principal component analysis, widely used in chemical and biological sciences. 3…”

Pretreatment of Mass Spectral Profiles: Application to Proteomic Data

“…The reduction in signal intensity accompanying the n th root transform also impacts regions with intensity close to noise level, and this may lead to loss of information for such regions. In such cases, it may be convenient to do a normalization and local PCA just on these regions without the n th root transform since without the presence of high-intensity regions, normalization of data is less influenced by heteroscedastic noise …”

Quantification of plasma lipids and apolipoproteins by use of proton NMR spectroscopy, multivariate and neural network analysis

“…It has earlier been reported that shifting of just a few points of the lactate peaks from spectra to spectra might be fatal for PCA of 1 H NMR spectra of blood plasma. 64 Leaving out the lactate peaks from the spectra in our X-matrix caused no differences in calibration (results not shown). The reason for this is probably based on both that the chemical shift of the lactate peaks in our spectra is relatively constant, and that the variation in lactate signal amplitude (concentration) is not systematic.…”

Mrs-based Metabolomics in Cancer Research

“…1,2 Another frequently used method is principal component analysis, widely used in chemical and biological sciences. 3 Once the critically sensitive spectral components have been identified, a method to quantify this sensitivity is necessary. One commonly used method is partial least squares discriminant analysis (PLS-DA), where assessment of goodness of fit is taken to indicate the accuracy of the method.…”

“…1,2 Another frequently used method is principal component analysis, widely used in chemical and biological sciences. 3…”

Pretreatment of Mass Spectral Profiles: Application to Proteomic Data

“…The reduction in signal intensity accompanying the n th root transform also impacts regions with intensity close to noise level, and this may lead to loss of information for such regions. In such cases, it may be convenient to do a normalization and local PCA just on these regions without the n th root transform since without the presence of high-intensity regions, normalization of data is less influenced by heteroscedastic noise …”

Quantification of plasma lipids and apolipoproteins by use of proton NMR spectroscopy, multivariate and neural network analysis

“…It has earlier been reported that shifting of just a few points of the lactate peaks from spectra to spectra might be fatal for PCA of 1 H NMR spectra of blood plasma. 64 Leaving out the lactate peaks from the spectra in our X-matrix caused no differences in calibration (results not shown). The reason for this is probably based on both that the chemical shift of the lactate peaks in our spectra is relatively constant, and that the variation in lactate signal amplitude (concentration) is not systematic.…”

Mrs-based Metabolomics in Cancer Research

“…1,2 Another frequently used method is principal component analysis, widely used in chemical and biological sciences. 3 Once the critically sensitive spectral components have been identified, a method to quantify this sensitivity is necessary. One commonly used method is partial least squares discriminant analysis (PLS-DA), where assessment of goodness of fit is taken to indicate the accuracy of the method.…”

“…1,2 Another frequently used method is principal component analysis, widely used in chemical and biological sciences. 3…”