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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Biomedical Engineering Research
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Journal DOI :
The Korea Society of Medical and Biological Engineering
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Volume & Issues
Volume 12, Issue 4 - Dec 1991
Volume 12, Issue 3 - Sep 1991
Volume 12, Issue 2 - Jun 1991
Volume 12, Issue 1 - Mar 1991
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Dynamic Behavior Analysis of Mechanical Bileaflet Heart Valve Prosthesis
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 149~156
In this paper, fluttering behavior of mechanical bileaflet heart valve prosthesis was analyzed taking into consideration of the impact between valve plate and stopper Vibration system of the valve was modeled as a rotating system, and equations are induced by moment equilibrium equations. Lift force, drag force, gravity and buoyancy were considered as external forces acting on the valve plate/ The 4th order Runge-Kutta method was used to solve the equations. Valve plate does not come to the static equilibrium position at a stretch, but come to that position after under damping vibration. Damping ratio increases as the cardiac optput increases, and the mean damping ratio is in the range of 0.16~40.25. Fluttering frequency does not have any specific value, but varies as a function of time. It is in the range of 10~40Hz. Valve opening appears to be affected by the orientation of the of the valve relative to gravitational forces.
Algin-Impregnated Vascular Graft II. Preliminary Animal Study
Jin Ho Lee ; Byu ;
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 157~164
double velour graft impregnated with a biodegradable algin was studied as a new vatscular graft. It is impervious to blood but still retains high porosity. This graft does not require preclotting during implantation and has good tissue ingrowth and biological healing properties. Two vascular grafts impregnated with algin (6mm in diameter) were implanted in the aorta of mongrel dogs without preclotting. Two identical grafts were preclctted and served as controls. The grafts were harvested 2 and 4 months postoperatively, and the healing pattern was examined by a light microscope after hemRtoxylineosin staining. It was observed that endothelial cells were incompletely covered on both algin-impregnated and control grafts after 2 month Implantation, while they were fully covered on both grafts after 4 month. There were no significant differences in subendothelial granulation tissue organization and fibrinoid material absorption between the algin-impregnated and control grafts. The algin-impregnated graft did not show any harmful effect on the healing and thus can be a new promising graft which is not necessary preclotting during the implantation.
Endothelial Cell Seeding onto Extracellular Matrix for Development of Polyurethane Vascular Prosthesis
Lee, Yoon-Shin ; Park, Dong-Kook ; Min, Byoung-Goo ;
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 165~170
Many experiments about endothelial cell seeding on artificial vessels were studied and conducted For this one or a combination of the extramatrix was used for the underlying matrix. But we used the whole ECM(extracellular matrix) that made excreated from flbroblasl. In thls study, we obtained human adult omental microvascular endothelium by collagenase digestion and used polyurthane sheets in order to make a new artificial vessel material. We cultured fibroblast on the polyurethane and gelatin - coated polyurethane. After confluent ingrowth we treated the polyure thane with triton in order to destroy the cytoskeleton and nucleus. We observed the preformed extra cellular matrix on the ployurethane and cultured the isolated microvascular endothelium. We also ok served the growth of microvascular endothelium on the polyurethane and gelatin. We conclude that the use of the whole ECM is promising fair as a new underying substrate for endothelial cell seeding on artificial vessels.
A Study on the Solution of the Epidemic Model Using Elementary Series Expansions
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 171~176
A solution for the course of the general deterministic epidemic model is obtained by elementary series expansion. This is valid over all times, and appears to hold accurate]y over a very wide range of population and threshould parameter values. This algorithm can be more efficient than either numerical or recursive procedures in terms of the number of operations required to evaluate a sequence of points along the course of the epidemic.
Measurements of Temperature Characteristics of The Lung Inflation and Deflation Reflexes Using Automated Vagal Cooling System in Anesthetized Dogs
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 177~184
Characteristics of the lung inflation and deflation reflexes were measured at various temperatrues on the cervical vagi in five anesthetized mongrel dogs. Nerve temperature was maintained at the body temperature, and
apart using a specially designed automated vagal cooling apparatus with an accuracy to within
at each temperature. The inflation reflex was blocked abruptly at
. The deflation reflex started weakened at
, thereafter showed a gradual blockade with the temperature decreased with a substantial variance among the animals. It was approximately 75% blocked at
. These differences in temperature characteristics made it hard to differentiate the deflation reflex from the inflation reflex. In one animal, however, the inflation reflex was completely blocked with the deflation reflex almost alive at
. This suegests that differential cold blockade of the vagal reflexes can be done only in selected subjects. Fur- thermore, the fact that these two reflexes were blocked at different temperatures may be due to the differences in the nerve fiber size and the changes in the conduction velocity with temperature.
Mesurement of Evoked Otoacoustic Emission Latency Using Linear Prediction Coding Spectrum
An, Jung-Il ; Choi, Jin-Young ; Lee, Kuhn-Il ;
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 185~190
An automatized latency calculation method of an e-OAE(evoked otacoustic emission) is proposed. The e-OAE signal measured from a normal adult is averaged 1000 times to remove noises. This averaged signal is converted to digital signal and that is processed by IBM-AT computer for latency calculation. we separate the stimulated and the emitted signal on the time domain by a modified LPC (linear prediction coding) spectrum, and the latency is calculated by cross-correlation method. By proposed latency calculation method the latency is 7.9[ms] for normal adult. The performance of the proposed method is also compared with that of the auto-correlation and cross performance of the proposed method is also compared with that of the auto-correlation and cross-correlation method. The result show that the proposed method has same precision with the conventional methods and can automatically calculate latency without subjective observation.
A Study on ECG Oata Compression Algorithm Using Neural Network
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 191~202
This paper describes ECG data compression algorithm using neural network. As a learning method, we use back error propagation algorithm. ECG data compression is performed using learning ability of neural network. CSE database, which is sampled 12bit digitized at 500samp1e/sec, is selected as a input signal. In order to reduce unit number of input layer, we modify sampling ratio 250samples/sec in QRS complex, 125samples/sec in P & T wave respectively. hs a input pattern of neural network, from 35 points backward to 45 points forward sample Points of R peak are used.
Fuzzy Control Method for Balancing Left and Right Cardiac Output in Total Artificial Heart
Shin, In-Sun ; Kim, Bo-Yeon ; Lee, Sang-Hoon ; Choi, Jin-Wook ; Min, Byoung-Goo ;
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 203~208
Balancing left/right cardiac output is essential for the automatic control of total artificial hearts(TAH). A fuzzy logic-based control method is presented. We use left atrial pressure( LAP) ann right a'rial pressure( RAP ) as indicators for left/right balancing. The fuzzy controller has four input variables which are measured LAP and RAP and their gradients. Desired variations in left cardiac output(LCO) and right cardiac output(RCO) are cal- culated to keep LAP and RAP within the Physiological limlts. Computer simulations were performed to adjust fuzzy membership functions for variables and verify this control method. Results from simulations showed that LAP and RAP returned to the physiological limits while AoP and PAP stayed within the physiological limits.
A Study on The Davelopement of Electronic Fetal Heart Rate Monitoring System Using Personal Computer
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 209~214
Digital fetal monitoring system based on the personal computer combined with the digital signal processing (DSP) board was implemented. The DSP board acquires and digitally processes ultra- sound fetal Doppler signal for digital signal conditioning, rectification, low -pass filtering, autocorrealtion function calculation and its peak detection. The personal computer interfaced with the DSP board is in charge of graphic display, hardcopy, data transmission and on -line analysis of fetal heart rate change including on - line warning system, base -line estmation, acceleration, deceleration and variability. It is one of the most suitable situation to apply the DSP chip for siganl conditioning, digital filtering of ultrasound fetal Dopier signal and fetal heart rate estimation using autocorrelation technique .
A Study on the Development of a MPACS
Journal of Biomedical Engineering Research, volume 12, issue 3, 1991, Pages 215~222
In this paper, we present a result of our study on how to construct a pilot MPACS (medical hic lure archiving and communication System) based on X -Window system. The proposed MPACS Is composed of image acquisition units, image archiving and processing units, display units, and all units are Interfaced with a LAN The image management is done according to the TIFF (Tagged Image File Format) , and the dis- play system is built upon generally accepted software packages, namely the X -Window system. Also, lossless and lossy digital image compression methods were implemented and tested with X -ray and CT images.