Multicomponent Analysis of Near-Infrared Spectra of Anesthetized Rat Head: (I) Estimation of Component Spectra by Principal Component Analysis
Near-infrared (NIR) spectrophotometry has been proposed for continuous and noninvasive monitoring of Hb oxygenation (So2) and redox state of cyt. aa3 in living tissues (Jöbsis, 1977 and others). In the previous articles, however, it has been assumed that only Hb and cyt. aa3 contribute to changes in NIR spectra of the tissues. Since various biological materials exist in the living organs, spectral changes of the other kinds of biological chromophores may be involved in the changes in NIR spectra of the tissues. We attempted to establish a method for quantitating near-infrared spectra of anesthetized rat head using multiple regression analysis of the spectral data which is so-called the ‘curve-fitting technique’ (Araki and Nashimoto, this volume). However, the number and standard spectral curves of ingredients of the mixtures must be already known to establish quantitative analysis by this technique (Leggett, 1977).
KeywordsPrincipal Component Analysis Methyl Orange Data Spectrum Acute Hypoxia Component Spectrum
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