Journal of Oleo Science
Online ISSN : 1347-3352
Print ISSN : 1345-8957
ISSN-L : 1345-8957
General Subjects
Short-time Fourier Transform of Free Induction Decays for the Analysis of Serum Using Proton Nuclear Magnetic Resonance
Keiko HirakawaKaoru KoikeYoshimasa KanawakuTsuyoshi MoriyamaNorio SatoTakao SuzukiKenichi FurihataYoukichi Ohno
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2019 Volume 68 Issue 4 Pages 369-378


Proton nuclear magnetic resonance (NMR) is useful for the analysis of biological samples such as serum. Free induction decays (FIDs) are NMR signals that follow a radio-frequency pulse applied at the resonance frequency. Short-time Fourier transform (STFT) is a basic method for time-frequency analyses. The purpose of this study was to ascertain whether the STFT of FIDs enables the sensitive detection of changes and differences in serum properties. FIDs were obtained from serum collected from young, healthy, male volunteers ≤ 40 years of age and seniors ≥ 65 years of age. Temporal changes in the instantaneous amplitudes for the time-domain analysis, fast Fourier transform for frequency-domain analysis, and STFT were applied to the FIDs. The STFT-based spectrogram represented the complex frequency components that changed dynamically over time, indicating that the spectrogram enabled the visualization of the features of an FID. Furthermore, the results of a partial least-squares discriminant analysis demonstrated that the STFT was superior to the other two methods for discriminating between serum from younger and older subjects. In conclusion, the STFT of FIDs obtained from proton NMR measurements was useful for evaluating similarities and dissimilarities in the FIDs obtained from serum samples.

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© 2019 by Japan Oil Chemists' Society
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