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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 16, Issue 4 - Dec 1995
Volume 16, Issue 3 - Sep 1995
Volume 16, Issue 2 - Jun 1995
Volume 16, Issue 1 - Mar 1995
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Endothelial Cell Seeding Onto the Extracellular Matrix of Fibroblasts for the Developement of Small Diameter Polyurethane Vessel
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 1~8
A variety of experiments of endothelial cell seeding onto artificial vessels have been performed. To improve endothelialization, one or two components of the extracellular matrix (ECM) have been used as an underlying matrix. In this study, the whole ECM excreted from fibroblasts was used as an underlying matrix. Fetal human fibroblasts were cultured on a polyurethane (PU) sheet. After a conflu; ence was attained, the cytoskeleton and the nuclei of the fibroblast were destroyed using Triton-X. Mitomycin, or irradiation. Omental microvascular endothelial cells from adult human were seeded onto various substrates. After 12 days in culture, the cells were counted. It was observed that the ECM treated by irradiation had the highest cell number. In addition, the cells on this substrate exhibited the most typical endothelial cell morphology. For preliminary animal experiments the PU vessels (inner diameter, 1.5mm) coated with ECM were implanted in the infrarena] abdominal aorta of rat. After the vessels had been implanted for 5 weeks, it was found that the surface of the PU vessels was completely covered with endothelia] cells. In conclusion, we can state that the fibroblast-derived whole ECM makes a better underlying substrate for the endothelialization of small diameter artificial vessels.
Synthesis and Characterization of Biocompatible and Biodegradable Polyesters (II):Crystallization and Biodegradation of Poly (1,4-butanediol succinate)
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 9~16
Biodegradable poly (I ,4-butanediol succinate) (PBS) was synthesized from 1,4-butanediol and succinic anhydride. The glass transition temperature of poly (I, 4-butanediol succinate) was revealed at
. The crystallization and cold crystallization of the polymers were investigated as a function of holding time in melt state, cooling rate. reheating, and molecular weight. Chain scission and/or cmsslinking did not occur in the melt state at var.ious holding times. Slower scanning rate can allow more times for nucleation, rearrangement, and packing of the polymer chain, so the onset temperature of crystallization from the melt was increased. PBS crystallized from the melt was found to have spherulitic structure. The degradation behavior of PBS was studied under basic conditions and with microorganisms using the modified ASTM method. In the basic solution. PBS lost up to 85% of its mass within two days. Based upon visual observation, the crystalline structure of films composed of larger molecular weight polymers retained their crystallinity longer than similar structures in low molecular weight samples.
A Study on the Holter Data Compression Algorithm -Using Piecewise Self-Affine Fractal Model-
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 17~24
This paper presents a new compression method (or ECG data using iterated contractive transformations. The method represents any range of ECG signal by piecewise self-afrine fractal Interpolation (PSAFI). The piecewise self-afrine rractal model is used where a discrete data set is viewed as being composed of contractive arfine transformation of pieces of itself. This algorithm was evaluated using MIT/BIH arrhythmia database. PSAFI is found to yield a relatively low reconstruction error for a given compression ratio than conventional direct compression methods. The compression ratio achieved was 883.9 bits per second (bps) - an average percent rms difference (AFRD) of 5.39 percent -with the original 12b ECG samples digitized at 400 Hz.
Two-Dimensional Finite Element Analysis of Bone Resorption from the Artificial Hip Replacement
Choi, Hyung-Yeon ; Chae, Soo-Won ; Kim, Sung-Kon ;
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 25~32
Clinically, proximal bone resorption in the femur is frequently seen postoperatively on the follow up XI-rays after total hip replacement (THR). We developed the finite element model of cementless THR. The model is two dimensional side plate model, whereby the three dimensional structural integrity of the bone can be accounted for by a separate two dimensional mesh, a side plate. The subject of this article is the development and application of this two dimensional side plate FEM to study the reverse effect of the various degree of bone resorption of femur after THR. The results of this study indicates that 1) two dimensional side plate model is good and simple alternative to complex three dimensional model and 2) the severity of the proximal bone resorption has the effect of more increasing stress on the cortex at the level of femoral stem tip.
Design of a pattern recognizing neural network using information-processing mechanism in optic nerve fields
Kang, Ick-Tae ; Kim, Wook-Hyun ; Lee, Gun-Ki ;
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 33~42
A new neural network architecture for the recognition of patterns from images is proposed, which is partially based on the results of physiological studies. The proposed network is composed of multi-layers and the nerve cells in each layer are connected by spatial filters which approximate receptive fields in optic nerve fields. In the proposed method, patterns recognition for complicated images is carried out using global features as well as local features such as lines and end-points. A new generating method of matched filters representing global features is proposed in this network.
Realization of a High Speed Optic Scanner for Infrared Thermal Imaging
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 43~48
Realization of a High Speed Optic Scanner for Infrared Thermal Imaging A high speed optic scanner capable of 16 frames/sec imaging has been developed for the realization of the infrared thermal Imaging system with a single element infrared sensor. The high speed optic scanner is composed of a rotating polygon mirror for horizontal scanning, a flat mirror mounted on a galvanometer for vertical scanning, and a spherical mirror. It has been experimentally found that the optic scanner is capable of 16 framesllsec imaging with the frame matrix size of 256 x 64
Design of Two Stage Amative Filters for Real time QRS Detection
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 49~56
This paper is a study on the design of adptive filter for QRS complex detection. We propose a simple adaptive algorithm to increase capability of noise cancelation in QRS complex detection with two stage adaptive filter. At the first stage, background noise is removed and at the next stage, only spectrum of QRS complex components is passed. Two adaptive filters can afford to keep track of the changes of both noise and QRS complex. Each adaptive filter consists of prediction error filter and FIR filter. The impulse response of FIR filter uses coefficients of prediction error filter. The detection rates for 105 and 108 of MIT/BIH data base were 99.3% and 97.4% respectively.
Biodegradable Inorganic-Organic Composite Artificial Bone Substitute
Suh, Hwal ; Lee, Jong-Eun ; Ahn, Sue-Jin ; Lee, Choon-Ki ;
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 57~60
To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed and produced a composite that is consisted of calcium phosphate and collagen. Human umbilical cord origin pepsin treated type I atelocollagen was used as the structural matrix, by which sintered or non-sintered carbonate apatite was encapsulated to form an inorganic-organic composite. With cross linking atelocollagen by UV ray irradiation, the resistance to both compressive and tensile strength was increased. Collagen degradation by the collagenase induced collagenolysis was also decreased.
Hemodynamic Evaluation of Monoleaflet Polymer Valve
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 61~66
We have developed a monoleaflet polymer valve as an inexpensive and viable alternative, especially for short-term use in the ventricular assist device or total artificial heart. The frame and leaflet of the polymer valve were made from polyurethane. To evaluate the hemodynamic performance of the polymer valve a comparative study of flow dynamics past a polymer valve and a St. Jude Medicals prosthetic valve under physiological pulsatile flow conditions in vitro was made. Comparisons between the valves were made on the transvalvular pressure drop, regurgitation volume and maximum valve opening area. The polymer valve showed smaller regurgitation volllme and transvalvular pressure drop compared to the mechanical valve at higher heart rate. The results showed that the functional characteristics of the polymer valve compared favorably with those of the mechanical valve at higher heart rate.
Effect of Parameters in Evaporative Removal Process by Absorption of a CW Laser
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 67~76
Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd: YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as BrJ, and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased. To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained.
N1-N2 Audiograms of the Guinea Pig Cochlea
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 77~84
Nl and N2 gross neural action potentials were measured from the round window of the guinea pig cochlea at the onset of the acoustic stimuli. Nl -N2 audiograms were made by means of regulating stimulant intensities in order to produce constant Nl -N2 potentials as criteria for different input tone pip frequencies. The lowest threshold was measured with an input tone pip 15 dB SPL in intensity and 12 KHz in frequency when the animal was in normal physiological condition. The procedure of experimental measurements is explained in detail. This experimental approach is very useful for the investigation of the Cochlear function. Both nonlinear and active functions of the Cochlea can be monitored by Nl -N2 audiograms. Key words : Guinea Pig, Cochlea, Wl and N2 Gross Neural Action Potential, Nl -N2 Audiogram
Development of Measurement System of Public Strength for Physical Fitness
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 85~94
We have developed MSPF (measurement system for physical fitness) which measures physical strength and body dimensions. This system has two main features, one is an automatic measurement of physical fitness, and the other is reducement of reading and writing errors caused by human during measurement. Using the MSPF, total ten items can be measured such as weight, height, sit up, push up,. etc. Since the system which have objectification and high precision has been needed, we used a memory card. By using this, it was easy to save and archive data by computer.
Assessment of Laryngeal Function by Pitch Perturbation Analysis and Hilbert Transform of EGG Signal
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 95~100
In this study, we have evaluated the effect of amplitude and frequency perturbation of EGG signal for single vowels associated with laryngeal pathology. The normal EGG signal was properly characterized by an autoregressive model which has an optimal order of ninth using the parametric method. This can be analyzed by determining the transfer function. Perturbations in the fundamental pitch and in the peak amplitude of EGG signal measured with a four-electrode system using the modulation/demodulation techniques were investigated for the purpose of developing a decision criteria for the laryngeal function analysis. The abnormal EGG signal has nonperiodic and unstable characteristics. It can be discriminated by the calculation of opening and closing time of glottis using the EGG signal. In case of normal and abnormal subjects, m
0.5*sd was discriminating line for frequency perturbation and m
2*sd for normal amplitude perturbations, respectively. Also, The normal and abnormal cases of the subjects can be discriminated effectively using the pattern of attractor derived with Hilbert transform of EGG signal.
Development of the Patient Monitor Using Microprocessor(II)
Kim, Nam-Hyun ; Kim, Jeong-Lae ; Huh, Jae-Man ;
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 101~106
In this paper, the patient monitor consisting of ECG/Respiration Amplification, Front end CPU, Main CPU, Main Controller, Video Amplifier, Display Controller, Waveform Generator, Bus & Power Supply, 8097 Processor was developed. This patient monitor measures the patient's states in the hospital such as elecctro-cardiography, respiration, blood pressurae and temperature. The control and processing methods based on micro-processor employ the flexibility, extensibility over other conventional system. The followings are incorporated in this system. First, ECG/RESP measures the respiration by impedence pneumography. Second, FECPU utilizes an Intel 8031 microcontroller. Third, Controller function originate from a LSI CRT controller.
64 channels computerized cardiac mapping system
Journal of Biomedical Engineering Research, volume 16, issue 1, 1995, Pages 107~113
It is well known that multipoint and computerized intraoperative mapping systems improve the results of surgery for Wolff-Parkinson-White syndrome and show tremendous potential for opening an entirely new era of surgical intervention for the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, the ability to map and ablate the sometimes fleeting automatic atrial tachycardia is greatly enhanced by computerized mapping systems. In this study, we have developed 64 channel computerized data analysis system using microcomputer (Macintosh
) for basic research of electrophysiology and electrical propagation. The bipolar electrogram information is acquired from 64 cardiac sites simultaneously at a sampling rate of 1 ksampls/sec with continuous and total data storage of up to 30 seconds. When the reference electrogram is selected and reference point is picked up, delay time from the reference point is displayed on two dimensional diagram of the heart. System design permits easy expansion to almost 256 simultaneous sites. this system is expected to enable us to study pathophysiology of cardiac arrhythmia and to improve the result of diagnosis and surgical treatment for cardiac arrhythmia.