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Heart rate variability and motion artifact are two major obstacles to the photoplethysmographic (PPG) signal analysis, which is a very promising tool to derive useful information about the hemodynamics as well as autonomic nerve system. This paper suggests employing a truncation/extrapolation method on the PPG signal or its first order derivative to overcome the heart rate variability problem while...
Previous studies used fixed wavelength modulated light to demonstrate the relationship between critical flicker frequency threshold (CFFT) and the factors of the subjects. We address a method to assess the whole human visual spectral sensitivity curve (with the visible range of wavelength) to CFFT by frequency modulated light. The color sensitivity curve of three cones of human eyes is discussed as...
Cerebral oxygenation especially regional cerebral oxygen saturation (rSO2) needs to be monitored to avoid irreversible damages induced by hypoxia. Based on steady-state spatially resolved spectroscopy (SRS), rSO2 was obtained by the NIRS oximeter developed by our group. The oximeter was calibrated by blood gas analyzer using the liquid tissue model made up by our group. The results indicate that the...
This paper proposes to use the pulse transit time variability (PTTV) as an indicator of the variability in hemodynamics and studies its correlation with other cardiovascular variabilities, especially the blood pressure variability (BPV), which receives increasing attentions as an independent indicator of autonomic regulation and abnormalities in cardiovascular system. Continuous blood pressure (BP),...
Genetic algorithm is used to perform variable selection to determine the ranges of wavelengths in NIR spectral data suitable to be used as predictors in multivariate calibration model via partial least squares. The NIR spectral data consists of three components of active substances, namely human serum albumin (HSA), gamma-globulin and glucose. The wavelength selection is able to improve the calibration...
The terahertz pulse (THz pulse) propagation in biological tissue is simulated by Monte Carlo method (MCM). The migratory route of THz pulse in the tissue is presented. The computation model is based on the assumption that the refraction indexes of tissue and air are mismatch and both surfaces of the tissue have the reflection effect for THz pulse
Laser-induced fluorescence spectroscopy (LIF) and Raman spectrum of serum for detection of colon cancer and rectum cancer were investigated in this paper. The aim of this study was that using Raman spectrum and LIF analysis the serum of colon cancer and rectum cancer for found the difference compared to normal, the difference was found. For example: the peaks intensity and red shift are both different...
This study assessed the feasibility of neonatal cerebral oxygen monitoring by near-infrared light spectroscopy (NIRS) using a light emitting diode (LED) based system. We aimed to measure the changes in cerebral oxygen saturation, as regional oxygen saturation and tissue oxygenation index, in response to auditory stimuli. Documenting changes in oxygenation in response to such stimuli will help validate...
Brain hemodynamic responses (BHR) of healthy subjects and migraineurs performing a breath holding task are measured by functional near-infrared spectroscopy (fNIRS) method. The response curves are deconvolved from a rectangular input function to yield the impulse response (IR) function of BHR which was then modeled by a summation of three gaussians. Our results show that the amplitude coefficients...
A Barker sequence is employed for the synchronization of two photoplethysmogram (PPG) channels. The correctness of this technique is demonstrated by recording a PPG signal, injecting a Barker sequence at the start of this trace and producing a delayed version of it. After preprocessing, cross-correlation techniques are utilized for accurate time alignment of the two traces. The algorithm can correct...
We developed a brand-new method that fits the non-invasive blood component concentration measurement: the dynamic spectrum (DS) method. With use of this method, it was possible to eliminate the main interference of the individual discrepancy and extract some kinds of the blood component concentration by the analytic method. The definition, principle and measure method of the dynamic spectrum are presented...
An analysis of pulse-to-pulse interval (PPI) derived from non-contact photoplethysmography (PPG) is performed using the Poincare plot technique. Eleven healthy volunteers participated in a protocol utilising both spontaneous and paced breathing methodologies with a customised non-contact PPG system to obtain adequate quality signals for a distance of 80 mm between source and detector. An adaptive...
Automation in near-patient ABO testing has been prohibitive due to cost. Recently, a spectrophotometric approach to blood typing has been developed by examining the spectral slopes of RBC suspensions in saline, in the presence and absence of various antibodies. In this paper, we present a simplified method and a sensor that can replace the spectral imaging component of the diode-array spectrophotometer...
We could get valuable information about various diseases by analyzing urine of patients. For the diabetics, it has been very important to know the glucose concentration in their urine. Until now, there have been many methods to estimate the concentration but they were invasive and annoyed patients. The low-resolution Raman spectroscopy (LRRS) could be an alternative method to be non-invasive and unconscious...
The development of near-infrared-based techniques for the noninvasive determination of blood component concentrations has attracted significant interest in recent years. Therefore, the noninvasive measurement of blood compositions has not yet been applied to the clinical field. The most important difficult problems are the effects of the individual discrepancy and other complicated measurement detection...
The present work shows the development of a low-cost system to measure on-line blood urea concentration during dialysis procedures using optical sensor in the visible range. The objective in this project is obtaining the quantification of urea on-line during practices of the hemodialysis treatments. For which it has been considered to be a hypothesis that the dependence in the volume change of the...
To estimate the oxygen consumption rate of arteriolar walls we measured the intra- and perivascular partial oxygen tension (PO2 ) of arterioles in rat cremaster muscle, both at resting and vasodilating states by phosphorescence quenching technique. Using measured intra- and perivascular PO2 values, oxygen consumption rates were determined based on Krogh-Erlang analysis. We found a significant drop...
Many researches for useful status information on humans have been done using the bio-signals. The bio-signal acquisition systems can be used to connect a user and a ubiquitous computing environment. The ubiquitous computing environment has to give various services anywhere, anytime. Consequently, ubiquitous computing requires new technology, such as a new user interface, dynamic service mechanism...
With the evolution of m-Health, an increasing number of biomedical sensors will be worn on or implanted in an individual in the future for the monitoring, diagnosis, and treatment of diseases. For the optimization of resources, it is therefore necessary to investigate how to interconnect these sensors in a wireless body area network, wherein security of private data transmission is always a major...
Optical properties of living tissues have not been well established even today, and biooptic instrumentations have to be based on empirical formulae. In order to examine optical properties of the tissue having pulsating blood perfusion, we investigated the relation between optical density (defined as O.D.) of whole blood and hematocrit by transmission spectrophotometry. We used Waseda mock circulatory...
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