• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.1032-1040
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• 2001

It is widely accepted that the pressure variation of interstitial fluid is one of the most important factors in bone physiology. In order to understand the role of interstitial fluid on porous bony structure, a consideration for the biomechanical interactions between fluid and solid constituents within bone is required. In this study, a poroelastic theory was applied to investigate the elastic behavior of calf vertebral trabecular bone composed of the porous solid trabeculae and the viscous bone marrow. The poroelastic behavior of trabecular bone in a uniaxial stress condition was simulated using a commercial finite difference analysis software (FLAC, Itasca Consulting Group, USA), and tested for 5 different strain rates, i.e., 0.001, 0.01, 0.1, and 10 per second. The material properties of the calf vertebral trabecular bone were utilized from the previous experimental study. Two asymptotic poroelastic responses, the drained and undrained deformations, were predicted. From the predicted results for the simulated five strain rates, it was found that the pore pressure generation has a linearly increasing behavior when the strain rate is the highest at 10 per second, otherwise it showed a nonlinear behavior. The pore pressure generation with respect to the strain was found to be increased as the strain rate increased. The elastic moduli predicted at each strain were 208.3, 212.2, 337.6, 593.1, and 602.2 MPa, respectively. Based on the results of the present study, it was suggested that the calf vertebral trabecular bone could be modeled as a poroelastic material and its strain rate dependent material behavior could be predicted.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.161-172
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• 2002

The present study evaluated the effects of guided tissue regeneration using xenograft material(deproteinated bovine bone powder), with and without biodegradable membrane in beagle dogs. Contralateral fenestration defects (6 ${\times}$ 4mm) were created 4 mm apical to the buccal alveolar crest of maxillary premolar teeth in 5 beagle dogs. Deproteinated bovine bone powders were implanted into fenestration defect and one randomly covered biodegradable membrane (experimental group). Biodegradable membrane was used to provide GTR. Tissue blocks including defects with soft tissues which were harvested following four & eight weeks healing interval, prepared for histo-phathologic analysis. The results of this study were as follows. 1. In control group, at 4 weeks after surgery, new bony trabecular contacted with interstitial tissue and osteocytes like cell were arranged in new bony trabecule. Bony lamellation was not observed. 2. In control gruop, at 8 weeks after surgery, scar-like interstitial tissue was filled defect and bony trabecule form lamellation. New bony trabecular was contacted with interstitial tissue but defect was not filled yet. 3. In experimental group, at 4 weeks after surgery, new bony trabecular partially recovered around damaged bone. But new bony trabecular was observed as irregularity and lower density. 4. In experimental group, at 8 weeks after surgery, lamella bone trabecular developed around bone cavity and damaged tissue was replaced with dense interstitial tissue. In conclusion, new bone formation regenerated more in experimental than control groups and there was seen observe more regular bony trabecular in experimental than control groups at 4 weeks after surgery. In control group, at 8 weeks after surgery, the defects was filled with scar-like interstitial tissue but, in experimental group, the defects was connected with new bone. Therefore xenograft material had osteoconduction but could not fill the defects. We thought that the effective regeneration of periodontal tissue, could be achieved using GTR with biodegradable membrane.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.519-523
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• 2004

This study investigates micro-structural and mechanical properties of trabecular bone in human femoral head with and without osteoporosis using Micro-CT and finite element-model. 15 cored trabecular bone specimens with 20min of diameter were obtained from femoral heads with osteoporosis (T-score > -2.5 ) resected for total hip arthroplasty, and 5 specimens were removed from femoral head of cadavers, which has no history of musculoskeletal diseases. A high-resolution micro-CT system was used to scan each specimen to obtain histomorphometry indices. Based on obtained micro-images(pixel size=21.31㎛), a FE-model was created to determine mechanical property indices. While non-osteoporosis group had increases trabecular thickness, bone volume, bone volume fraction, degree of anisotropy and trabecular number compared with those of non-osteoporotic group, the non-osteoporotic group showed decreases in trabecular separation and structure model index. Regarding the mechanical property indices, reaction force, apparent stress and young's modulus were 1ower in osteoporotic group than in non-osteoporotic group. Our data shows salient deteriorations in trabecular micro-structural and mechanical properties in human femoral head with osteoporosis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.967-968
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.703-704
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• 2007

• The Journal of the Acoustical Society of Korea
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• v.30 no.3
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• pp.158-166
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• 2011

In the present study, copper and nickel foams with an open-celled structure as trabecular-bone-mimicking phantoms were used to investigate the dependencies of group velocity and attenuation coefficient on structural properties such as trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) in trabecular bone. The group velocity and attenuation coefficient of the copper and nickel foams were measured by a through-transmission method in water, using a pair of broadband, unfocused transducers with a diameter of 12.7 mm and a center frequency of 1.0 MHz. The separation of the Biot's fast and slow waves was consistently observed in the ultrasonic signals transmitted through the copper and nickel foams. The group velocities of the copper and nickel foams showed highly positive correlations with Tb.Th and Tb.Sp. The attenuation coefficient of the copper foam showed a highly negative correlation with Tb.Th and Tb.Sp, whereas that of the nickle foam showed a highly positive correlation with Tb.Th and Tb.Sp. These results advance our understanding of those previously reported by other researchers using trabecular bone samples or phantoms.

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.3.1-3.14
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• 2018

Type 1 diabetes mellitus (T1DM) is a pathological condition associated with osteopenia. $WNT/{\beta}$-catenin signaling is implicated in this process. Trabecular and cortical bone respond differently to $WNT/{\beta}$-catenin signaling in healthy mice. We investigated whether this signaling has different effects on trabecular and cortical bone in T1DM. We first established a streptozotocin-induced T1DM mouse model and then constitutively activated ${\beta}$-catenin in osteoblasts in the setting of T1DM (T1-CA). The extent of bone loss was greater in trabecular bone than that in cortical bone in T1DM mice, and this difference was consistent with the reduction in the expression of ${\beta}$-catenin signaling in the two bone compartments. Further experiments demonstrated that in T1DM mice, trabecular bone showed lower levels of insulin-like growth factor-1 receptor (IGF-1R) than the levels in cortical bone, leading to lower $WNT/{\beta}$-catenin signaling activity through the inhibition of the IGF-1R/Akt/glycogen synthase kinase $3{\beta}$ ($GSK3{\beta}$) pathway. After ${\beta}$-catenin was activated in T1-CA mice, the bone mass and bone strength increased to substantially greater extents in trabecular bone than those in cortical bone. In addition, the cortical bone of the T1-CA mice displayed an unexpected increase in bone porosity, with increased bone resorption. The downregulated expression of WNT16 might be responsible for these cortical bone changes. In conclusion, we found that although the activation of $WNT/{\beta}$-catenin signaling increased the trabecular bone mass and bone strength in T1DM mice, it also increased the cortical bone porosity, impairing the bone strength. These findings should be considered in the future treatment of T1DM-related osteopenia.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.1
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• pp.1-15
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• 2008

Purpose: Osteoporosis that occurred after menopause is one of the most common metabolic disease. and it is that bone mass significant decrease in comparison with normal people. Its symptoms are fracture, decrease of height, etc. The purpose of this study is to examine what are the effects of the Gamisoyosan on the aged ovariectomized rat model of postmenopausal osteoporosis. Methods: 24 female rats were ovariectomized and divided into normal group(normal), ovariectomized group(control), and treated with Gamisoyosan group(treated). During 8 weeks we dosed D.W to sham and control group, and dosed Gamisoyosan(105 mg/100 g) to experimental group. After 8 weeks we sacrificed rats and measured the body weight, albumin, P, Calcium, ALP, total cholesterol, triglyceride, AST, ALT, T4, estradiol, the femur weight, the tibia ash weight, trabecular bone area, trabecular thickness, osteoclast number. Results: The level of serum albumin, calcium, AST, ALT, estradiol in Gamisoyosan group showed significant increase in comparison with control group. The level of serum triglyceride in Gamisoyosan group showed significant decrease in comparison with control group. Trabecular bone area and osteoclast number in Gamisoyosan group showed significant increase in comparison with control group. Conclusions: Reviewing these experimental results, Gamisoyosan has shown to activate osteogenesis and prevent bone resorption, and it should show efficacy on prevention and improvement of osteoporosis after menopause.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.295-300
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• 2005

We introduce an x-ray micro tomography system capable of high resolution imaging of a local region inside a small animal. By combining two kinds of projection data, one from a full field-of-view (FOV) scan of the whole body and the other from a limited FOV scan of the region of interest, we have obtained zoomed-in images of the region of interest without any contrast a nomalies. We have integrated a micro tomography system using a micro-focus x-ray source, a $1248\times1248$ flat-panel x-ray detector, and a precision scan mechanism. Using the cross-sectional images taken with the zoom-in micro tomography system, we measured trabecular thicknesses of femur bones in postmortem rats. To compensate the limited spatial resolution in the zoom-in micro tomography images, we used the fuzzy distance transform for the calculation of the trabecular thickness. To validate the trabecular thickness measurement with the zoom-in micro tomography images, we compared the measurement results with the ones obtained from the conventional micro tomography images of the extracted bone samples.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1078-1080
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• 2002

The pressure variation of interstitial fluid is one of the most important factors in bone physiology. In order to understand the role of interstitial fluid and the biomechanical interactions between fluid and solid constituents within bone, poroelastic theory was applied. The purpose of this study is to describe the behavior of calf vertebral trabecular bone composed of the porous solid trabeculae and the viscous bone marrow by using a commercial finite element analysis program based on the poroelasticity. In this study, the model was numerically tested for 5 different strain rates, i. e., 0.001, 0.01, 0.1, 1.0, and 10 per second. The material properties of the calf vertebral trabecular bone were utilized from the previous experimental study. Two asymptotic poroelastic response, the drained and undrained deformation, were predicted. From the predicted results for the simulated five strain rate, it was found that the pore pressure generation has a linearly increasing behavior when the strain rate is the highest at 10 per second, other wise it showed a nonlinear the strain rate Increased. Based on the results of the present study, it was suggested that the calf vertebral trabecular bone could be modeled as a porous material and its strain rate dependent material behavior could be predicted.