A fingertip-type magnetic pulse detection device for unusual monitoring conditions

Figures

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  Fig. 1. Schematic of the fingertip-type MDVS device and measurement setup. a Measurement setup. b Photograph of assembled fingertip-type MDVS.

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  Fig. 2. Magnetic and vibrational signals obtained from two healthy subjects. a–c are signals obtained from subject A: a magnetic sensor output signal for a duration of 16 s, b average single pulse signal from (a), and c second derivative of (b). d–f are the corresponding magnetic signals measured from subject B. For comparison, g–i shows the vibrational signals measured simultaneously with d–f: g is the time-dependent displacement signal, h is the average single pulse signal and i is the average acceleration detected directly by the vibrometer.

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  Fig. 3. Pulse signals measured under diffident conditions. a Fingertip wrapped by a black tape, b fingertip wrapped by a plaster, and c fingertip immersed in water. Left panel: photography of the MDVS and fingertip during measurement; right panel: measured signals.

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  Fig. 4. Correlation analysis of magnetic and vibrational signals. a, b Comparison of single pulse signal magnetic and vibrational signals. The vibrational signals are measured using VibroFlex QTec (a) and VibroGo (b), respectively. c, d Bland–Altman plots based on repeated measurements using VibroFlex QTec (c) and VibroGo (d). The two blue dashed-lines denote ±1.96 SD, and the red dash-dotted line denotes mean bias of difference between the two signals.

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  Fig. 5. Simulated stationary field distribution and field change caused by magnet movement on the xz plane. Contour plots of a \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${H}_{x}$$\end{document}Hx in the range of ±100 Oe, b \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\triangle H}_{x}$$\end{document}△Hx caused by vertical shift of the top magnet by 50 μm, c \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\triangle H}_{x}$$\end{document}△Hx caused by a pitch rotation of 0.0033 rad, and d \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs}…

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