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ABSTRACT: We present a new method measuring body impedance using a thigh-to-thigh current path, which can reflect the abdominal fat portion more sensitively and can be conveniently applied during the daily use on a toilet seat. Two pairs of electrodes were installed on a toilet seat to provide current and to permit voltage measurement through a thigh-to-thigh current path. The effectiveness of the method was compared with conventional foot-to-foot and hand-to-foot current paths by simulation and by experiments referenced to computed tomography (CT) image analysis. Body impedance using three different current paths was measured, and abdominal CT images were acquired for eight subjects. Measured body impedances were compared with the visceral to subcutaneous fat ratio (VF/SF) calculated from the CT-determined abdominal fat volume. The thigh-to-thigh current path was about 75% more sensitive in abdominal fat measurement than the conventional current paths in simulation experiments and displayed a higher VF/SF correlation (r = 0.768) than the foot-to-foot (r = 0.425) and hand-to-foot (r = 0.497) current paths.
Medical & Biological Engineering 11/2009; 47(12):1265-71. · 1.76 Impact Factor
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ABSTRACT: Polysomnography (PSG) involves simultaneous and continuous monitoring of relevant normal and abnormal physiological activity during sleep. At present, an electroencephalography-based rule is generally used for classifying sleep stages. However, scoring the PSG record is quite laborious and time consuming. In this paper, movement and cardiac activity were measured unobtrusively by a load-cell-installed bed, and sleep was classified into two stages: slow-wave sleep and non-slow-wave sleep. From the measured cardiac activity, we extracted heartbeat data and calculated heart rate variability parameters: standard deviation of R-R intervals SDNN, low frequency-to-high frequency ratio, alpha of detrended fluctuation analysis and correlation coefficient of R-R interval. The developed system showed a substantial concordance with PSG results when compared using a contingency test. The mean epoch-by-epoch agreement between the proposed method and PSG was 92.5% and Cohen's kappa was 0.62.
Physiological Measurement 10/2009; 30(11):1163-70. · 1.68 Impact Factor
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ABSTRACT: In this study, optimal methods for re-sampling and spectral estimation in frequency-domain heart rate variability (HRV) analysis were investigated through a simulation using artificial RR-interval data. Nearest-neighbour, linear, cubic spline and piecewise cubic Hermite interpolation methods were considered for re-sampling and representative non-parametric, parametric, and uneven approaches were used for spectral estimation. Based on this result, the effects of missing RR-interval data on frequency-domain HRV analysis were observed through the simulation of missing data using real RR-interval tachograms. For this simulation, data including the simulated artefact section (0-100 s) were used; these data were selected randomly from the real RR data obtained from the MIT-BIH normal sinus rhythm RR-interval database. In all, 7182 tachograms of 5 min durations were used for this analysis. The analysis for certain missing data durations is performed by 100 Monte Carlo runs. TF, VLF, LF and HF were estimated as the frequency-domain parameters in each run, and the normalized errors between the data with and without the missing data duration for these parameters were calculated. Rules obtained from the results of these simulations were evaluated with real missing RR-interval data derived from a capacitive-coupled ECG during sleep.
Physiological Measurement 09/2009; 30(10):1039-50. · 1.68 Impact Factor
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ABSTRACT: A helmet-based system that was able to monitor the drowsiness of a soldier was developed. The helmet system monitored the electrocardiogram, electrooculogram and electroencephalogram (alpha waves) without constraints. Six dry electrodes were mounted at five locations on the helmet: both temporal sides, forehead region and upper and lower jaw strips. The electrodes were connected to an amplifier that transferred signals to a laptop computer via Bluetooth wireless communication. The system was validated by comparing the signal quality with conventional recording methods. Data were acquired from three healthy male volunteers for 12 min twice a day whilst they were sitting in a chair wearing the sensor-installed helmet. Experimental results showed that physiological signals for the helmet user were measured with acceptable quality without any intrusions on physical activities. The helmet system discriminated between the alert and drowsiness states by detecting blinking and heart rate variability (HRV) parameters extracted from ECG. Blinking duration and eye reopening time were increased during the sleepiness state compared to the alert state. Also, positive peak values of the sleepiness state were much higher, and the negative peaks were much lower than that of the alert state. The LF/HF ratio also decreased during drowsiness. This study shows the feasibility for using this helmet system: the subjects' health status and mental states could be monitored without constraints whilst they were working.
Arbeitsphysiologie 12/2008; 105(3):365-72. · 2.15 Impact Factor
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ABSTRACT: Inadequate bowel preparation is important because it can result in missed lesions, cancelled procedures, increased procedural time, and a potential increase in complication rates. This prospective study was designed to look at the quality of colon preparation using polyethylene glycol solution and evaluate potential associations between specific patient characteristics and inadequate bowel preparation.
A total of 362 patients who were compliant with preparation instructions were enrolled. All colonoscopic examinations were performed by an experienced endoscopist and the quality of the preparation was graded by the endoscopist (excellent to poor). Patient demographic and medical history information was gathered before the procedure. Possible predictors of inadequate colonic preparation were analyzed using univariate statistics and multivariate logistic regression models.
An inadequate bowel preparation was reported in 28.2% of observed colonoscopies. In multivariate regression analysis, age greater than 60 years [odds ratio (OR) 2.8, 95% confidence interval (CI) 1.04-7.4], a history of diabetes (OR 8.6, 95% CI 6.3-19.4), a history of appendectomy (OR 4.6, 95% CI 2.0-10.5), a history of colorectal resection (OR 7.5, 95% CI 3.4-17.6), and a history of hysterectomy (OR 3.4, 95% CI 1.1-10.4) were independent predictors of an inadequate colon preparation.
This prospective study identified several factors that may predict inadequate polyethylene glycol preparation independent of compliance with preparation instructions and procedure starting time. This result may help to identify patients at an increased risk for inadequate bowel preparation for whom alternative preparation protocols would be beneficial.
Journal of clinical gastroenterology 11/2008; 43(5):448-52. · 2.21 Impact Factor
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ABSTRACT: The effects of timing jitter in direct sequence binary phase shift keying (DS-BPSK) ultra wideband (UWB) systems applying the FCC-constraint pulses are investigated under at Nakagami-m fading channel and additive white Gaussian noise (AWGN). The numerical results show that two FCC-constraint pulses, Low band (LB)-PSP and LB-MMNHP, have almost same sensitivity to the timing jitter even though they have different transceiver complexity. Additionally, the additional power caused by the timing jitter exponentially increases, but the additional power caused by the amplitude fading is not exceeded over 7 dB.
TENCON 2004. 2004 IEEE Region 10 Conference; 12/2004
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ABSTRACT: In the field of image technology, three-dimensional (3D) image display can give the intuitive information more efficiently. In medical science, 3D visualization is used for the purpose of education and diagnosis and is becoming increasingly more important. In this article, several structures of the larynx are visualized by 3D image and displayed on the Web to provide users an easy approach to the image. VRML is used on Web3D display because it is popular and easy to manipulate.
Journal of Digital Imaging 02/2002; 15 Suppl 1:264-6. · 1.25 Impact Factor
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ABSTRACT: This study was to observe the changes of blastogenic responses of splenic lymphocytes to T-cell mitogens, N. fowleri lysate and concanavalin A, and serum antibody titer during the course of experimental PAM in mice. Naegleria fowleri, strain 0359, was cultured in the CGVS medium axenically and inoculated intranasally with 7 x 10(4) trophozoites for the development of experimental PAM in mice. The amoebae were subjected to ultrasonication and centrifuged at 20,000 g for 60 minutes, and filtered through 0.2 micro-m filter membrane. The supernatant, N. fowleri lysate, was used as T-cell mitogen, and antigen for ELISA. The serum antibody was examined by ELISA using peroxidase conjugate. Two hundred micro-l of 10(6) splenocytes in RPMI 1640 containing 10% fetal calf serum were added to each well of a microtiter plate. To each well was added T-cell mitogens, 100 micro-g/ml of N. fowleri lysate or 4 micro-g/ml of con. A, and the plates were incubated for 42 hours at 37 C in 5% CO(2) incubator. Cultures were pulsed with 1 micro-Ci of methyl-(3H)-thymidine 6 hour before harvesting. The mean blastogenic response of the splenocytes to N. fowleri lysate was reduced, whereas that to con. A was also reduced up to on day 11 after infection. Both of these results were statistically significant compared with those of uninfected control group. The serum antibody titers were increased gradually up to day 15. The results indicated that there was an impairment of the blastogenic response of splenocytes to N. fowleri lysate during the acute course of experimental PAM in mice.
Kisaengch'unghak chapchi. The Korean journal of parasitology. 07/1987; 25(1):1-6.
