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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 26, Issue 6 - Dec 2005
Volume 26, Issue 5 - Oct 2005
Volume 26, Issue 4 - Aug 2005
Volume 26, Issue 3 - Jun 2005
Volume 26, Issue 2 - Apr 2005
Volume 26, Issue 1 - Feb 2005
Selecting the target year
Design and Implementation of HL 7-based Real-time Data Communication for Mobile Clinical Information System
Choi Jinwook ; Yoo Sooyoung ; Chun Jonghoon ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 65~71
The main obstacles for adopting a mobile health information system to existing hospital information system are the redundancy of clinical data and the additional workload for implementing the new system. To obtain a seamless communication and to reduce the workload of implementation, an easy and simple implementation strategy is required. We propose a mobile clinical information system (MobileMed) which is specially designed for the easy implementation. The key elements of MobileMed are a smart interface, an HL7 message server, a central clinical database (CCDB), and a web server. The smart interface module transfers the key information to the HL7 message server as new clinical tests data is recorded in the existing laboratory information system. The HL7 message server generates the HL7 messages and sends them to the CCDS. As a central database the CCDS collects the HL7 messages and presents them to the various mobile devices such as PDA. Through this study we might conclude that the architecture for the mobile system will be efficient for real-time data communication, and the specially designed interface will be an easy tool for implementing the mobile clinical information system.
Topology Correction for Flattening of Brain Cortex
Kwon Min Jeong ; Park Hyun Wook ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 73~86
We need to flatten the brain cortex to smooth surface, sphere, or 2D plane in order to view the buried sulci. The rendered 3D surface of the segmented white matter and gray matter does not have the topology of a sphere due to the partial volume effect and segmentation error. A surface without correct topology may lead to incorrect interpretation of local structural relationships and prevent cortical unfolding. Although some algorithms try to correct topology, they require heavy computation and fail to follow the deep and narrow sulci. This paper proposes a method that corrects topology of the rendered surface fast, accurately, and automatically. The proposed method removes fractions beside the main surface, fills cavities in the inside of the main surface, and removes handles in the surface. The proposed method to remove handles has three-step approach. Step 1 performs smoothing operation on the rendered surface. In Step 2, vertices of sphere are gradually deformed to the smoothed surfaces and finally to the boundary of the segmented white matter and gray matter. The Step 2 uses multi-resolutional approach to prevent the deep sulci from geometrical intersection. In Step 3, 3D binary image is constructed from the deformed sphere of Step 2 and 3D surface is regenerated from the 3D binary image to remove intersection that may happen. The experimental results show that the topology is corrected while principle sulci and gyri are preserved and the computation amount is acceptable.
Real- Time Estimation of the Ventricular Relaxation Time Constant
Chun Honggu ; Kim Hee Chan ; Sohn Daewon ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 87~93
A new method for real-time estimating left ventricular relaxation time constant (T) from the left ventricular (LV) pressure waveform, based on the isovolumic relaxation model, is proposed. The presented method uses a recursive least squares (RLS) algorithm to accomplish real-time estimation. A new criterion to detect the end-point of the isovolumic relaxation period (IRP) for the estimation of T is also introduced, which is based on the pattern analysis of mean square errors between the original and reconstructed pressure waveforms. We have verified the performance of the new method in over 4,600 beats obtained from 70 patients. The results demonstrate that the proposed method provides more stable and reliable estimation of τ than the conventional 'off-line' methods.
EEG Current Source Imaging using VEP Data Recorded inside a 3.0T MRI Magnet
Han Jae Y. ; Choi Young H. ; Im Chang H. ; Kim Tae-S. ; Lee Soo Y. ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 95~99
We have performed EEG current source imaging on the cortical surface using visual evoked potentials (VEPs) recorded inside a 3.0 T MRI magnet. In order to remove ballistocardiogram (BCG) artifacts in the VEPs, an improved BCG template subtraction technique is devised. Using the cortically constrained current source imaging technique and pattern-reversal visual stimulations, we have obtained current source maps from 10 subjects. To validate the EEG current source imaging inside the magnet, we have compared the current source maps to the ones obtained outside the magnet. The experimental results demonstrate that there is a strong correspondence between the current source maps, proving that current source imaging is feasible with the evoked potentials recorded inside a 3.0 T MRI magnet.
Osteogenic Potential of the Periosteum and Periosteal Augmentation for Bone-tunnel Healing
Youn Inchan ; Suh J-K Francis ; Choi Kuiwon ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 101~110
Periosteum and periosteum-derived progenitor cells have demonstrated the potential for stimulative applications in repairs of various musculoskeletal tissues. It has been found that the periosteum contains mesenchymal progenitor cells capable of differentiating into either osteoblasts or chondrocytes depending on the culture conditions. Anatomically, the periosteum is a heterogeneous multi-layered membrane, consisting of an inner cambium and an outer fibrous layer. The present study was designed to elucidate the cellular phenotypic characteristics of cambium and fibrous layer cells in vitro, and to assess whether structural integrity of the tendon in the bone tunnel can be improved by periosteal augmentation of the tendonbone interface. It was found the cells from each layer showed distinct phenotypic characteristics in a primary monolayer culture system. Specifically, the cambium cells demonstrated higher osteogenic characteristics (higher alkaline phosphatase and osteocalcin levels), as compared to the fibrous cells. Also in vivo animal model showed that a periosteal augmentation of a tendon graft could enhance the structural integrity of the tendon-bone interface, when the periosteum is placed between the tendon and bone interface with the cambium layer facing toward the bone. These findings suggest that extra care needs to be taken in order to identify and maintain the intrinsic phenotypes of the heterogeneous cell types within the periosteum. This will improve our understanding of periosteum in applications for musculoskeletal tissue repairs and tissue engineering.
Effects of Stimulation Conditions and Waveforms on Muscle Contractile Characteristics
Song Tongjin ; Khang Gon ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 111~116
This study was designed to apply the stimulation system developed in our laboratory to investigate how the stimulation conditions affect the muscle contractile characteristics in the isometric condition as well as during the FES standing/walking. Four paraplegic and ten healthy subjects participated in this study, and their knee extensors were voluntary contracted or electrically stimulated to measure the muscle force and the fatigue index for different waveforms of the pulse train. We also investigated different combinations of the electrode positions during standing/walking. It was confirmed that continuous and high-frequency stimulation causes faster fatigue than intermittent and low-frequency stimulation. Fatigue resistance was higher around the optimal muscle length than at a stretched position in healthy subjects, whereas the opposite was observed in paralyzed subjects. The paired t-test results with the level of significance at 0.01 indicated that the sinusoidal waveform generated the largest torque among the four typical waveforms. Although statistically not very significant, the sinusoidal waveform also generated, in general, the highest fatigue resistance at an intensity level below the supramaximal stimulation. One of the paraplegic subject who participated in the standing/walking program can now stand up for 1 minute and 50 seconds with the knee extensors, and walk for about 5 minutes at the speed of 12m/sec.
Nondestructive Estimation of Mechanical Orthogonality of Human Trabecular Bone by Computed Tomography and Spherical Indentation Test
Bae Tae Soo ; Lee Tae Soo ; Choi Kuiwon ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 117~122
The elastic modulus and the apparent density of the trabecular bone were evaluated from spherical indentation tests and Computed Tomography (CT) and their relationship was quantified. The femurs were prepared for trabecular bone analysis. Embedded with respect to their anatomical orientation, the transverse planes of the trabecular bone specimens were scanned at 1㎜ intervals using a CT scanner. The metaphyseal regions of femurs were sectioned with a diamond-blade saw, producing 8㎜ cubes. Using a specially made spherical indentation tester, the cubes were mechanically tested in the anterior-posterior (AP), medial-lateral (ML), and inferior-superior (IS) directions. After determination of modulus from the mechanical testing, the apparent densities of the specimens were measured. The results showed that the IS modulus was significantly greater than both the AP and ML moduli with the AP modulus greater than the ML modulus. This demonstrated that orthogonality was a structural characteristic of the trabecular bone. The power relationship between the modulus and the apparent density was also found to be statistically significant.
Changes In Mechanical Strength of Compression HIP Screws in Relation to Design Variations - A Biomechanical Analysis
Moon S. J. ; Lee H. S. ; Jun S. C. ; Jung T. G. ; Ahn S. Y. ; Lee H. ; Lee S. J. ;
Journal of Biomedical Engineering Research, volume 26, issue 2, 2005, Pages 123~127
Compression Hip Screw (CHS) is one of the most widely-used prostheses for the treatment of intertrochanteric fractures because of its strong fixation capability. Fractures at the neck and screw holes are frequently noted as some of its clinical drawbacks, which warrant more in-depth biomechanical analysis on its design variables. The purpose of this study was to evaluate changes in the strength with respect to the changes in design such as the plate thickness and the number of screw holes. Both mechanical test and FEM analysis were used to systematically investigate the sensitivities of the above-mentioned design variables. For the first part of the mechanical test, CHS (n=20) were tested until failure. The CHS specimens were classified into four groups: Group Ⅰ was the control group with the neck thickness of 6-㎜ and 5 screw holes on the side plate, Group Ⅱ 6-㎜ thick and 8 holes, Group Ⅲ 7.5-㎜ thick and 5 holes, and Group Ⅳ 7.5-㎜ thick and 8 holes. Then, the fatigue test was done for each group by imparting 50% and 75% of the failure loads for one million cycles. For the FEM analysis, FE models were made for each group. Appropriate loading and boundary conditions were applied based on the failure test results. Stresses were assessed. Mechanical test results indicated that the failure strength increased dramatically by 80% with thicker plate. However, the strength remained unchanged or decreased slightly despite the increase in number of holes. These results indicated the higher sensitivity of plate thickness to the implant strength. No fatigue failures were observed which suggested the implant could withstand at least one million cycles of fatigue load regardless of the design changes. Our FEM results also supported the above results by showing a similar trend in stress as those of mechanical test. In summary, our biomechanical results were able to show that plate thickness could be a more important variable in design for reinforcing the strength of CHS than the number of screw holes.