• Journal of Mechanical Science and Technology
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• 제15권7호
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• pp.1022-1031
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• 2001

The elastic modulus and fatigue properties of canine and human trabecular bone tissues (single trabecular) were experimentally determined on a microstructural level using four-point bending cyclic test, and they were compared based on microstructural characteristics and mineral density. The results showed that canine trabecular bone tissue had significantly lower modulus and lower fatigue strength than human tissue. The observed microstructural differences between the two tissues may be more responsible for the differences, although the lower mineral density in canine tissue might also have contributed to the lower modulus and fatigue strength.

• Experimental and Molecular Medicine
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• 제50권12호
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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.

• 대한의용생체공학회:의공학회지
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• 제33권2호
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• pp.78-88
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• 2012

Knee joint instability by anterior cruciate ligament(ACL) rupture is allowing the abnormal loading condition at the tibial epiphysis locally, resulting in producing locally different bone bruise. The study examined difference between local alteration patterns of trabecular bone microarchitecture at medial and lateral parts of the tibial epiphysis by ACL rupture. Fourteen SD rats were divided into Control(CON; n = 7) and Anterior Cruciate Ligament Transection(ACLT; n = 7) groups. The tibial joints were then scanned by in vivo ${\mu}$-CT at 0, 4, and 8 weeks post-surgery. The results showed that alteration pattern on trabecular bone microarchitecture at medial part was significantly higher than that at lateral part of the tibial epiphysis in ACLT group from 0 to 8 weeks(P < 0.05). Tb.Th and Tb.Sp distributions were well corresponded with differences between aforementioned trabecular bone microarchitectural alteration pattens at medial and lateral parts of the tibial epiphysis in ACLT group from 0 to 8 weeks(P < 0.05). These findings suggest that the alteration patterns of trabecular bone microarchitecture should be locally and periodically considered, particularly with respect to the prediction of bone fracture risk by ACL rupture. Improved understanding of the alteration patterns at medial and lateral trabecular bone microarchitectures at the tibial epiphysis may assist in developing more targeted treatment interventions for knee joint instability secondary to ACL rupture.

• Journal of Korean Neurosurgical Society
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• 제61권5호
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• pp.559-567
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• 2018

Objective : The aim of this study was to evaluate the effect for biodegradable screws containing bone morphogenetic protein-2 (BMP-2) in an osteoporotic rat model. Methods : Twenty-four female Wistar rat (250-300 g, 12 weeks of age) were randomized into four groups. Three groups underwent bilateral ovariectomy (OVX). Biodegradable screws with or without BMP-2 were inserted in the proximal tibia in two implantation groups. The extracted proximal metaphysis of the tibiae were scanned by exo-vivo micro-computed tomography. Evaluated parameters included bone mineral density (BMD), trabecular bone volume (BV/TV), trabecular number, trabecular thickness, and trabecular separation (Tb.Sp). The tibia samples were pathologically evaluated by staining with by Hematoxylin and Eosin, and trichrome. Results : Trabecular formation near screw insertion site was evident only in rats receiving BMP-2 screws. BMD and BV/TV significantly differed between controls and the OVX and OVX with screw groups. However, there were no significant differences between control and OVX with screw BMP groups. Tb.Sp significantly differed between control and OVX and OVX with screw groups (p<0.05), and between the OVX and OVX with screw BMP group (p<0.05), with no statistically significant difference between control and OVX with screw BMP groups. Over the 12 weeks after surgery, bone lamellae in direct contact with the screw developed more extensive and thicker trabecular bone around the implant in the OVX with screw BMP group compared to the OVX with screw group. Conclusion : Biodegradable screws containing BMP-2 improve nearby bone conditions and enhance ostoeintegration between the implant and the osteoporotic bone.

• Journal of Mechanical Science and Technology
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• 제15권7호
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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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.923-926
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• 2005

To investigate the relationship between BMD, micro-structural and mechanical properties in intertrochanteric trabecular bone, the PIXI-mus2 system, micro-CT and FE model were used. The purpose of this study were (1) to apply high-resolution imaging techniques (micro-CT imaging) in combination with new computer modeling techniques (FEA) to quantify 3D microstructural and biomechanical properties of trabecular bone in the intertrochanteric region, and (2) determine if the prediction of bone elastic constant can be improved with structural index.

• 대한치과보철학회지
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• 제38권1호
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• pp.12-25
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• 2000

To demonstrate possible influences of general bone density on the mandible, histomorphometric analysis was carried out in mandibles and iliac bones and the correlation of the two bone densities was tested. Comparison of bony density in women and men over 60 years in the mandible was carried out too. Quantitative computed tomography(QCT) was taken in cross-section of mandibles at the same site where histomorphometric analysis was peformed to evaluate the reliability of QCT. The analysis included 40 cadavers with no known diseases affecting the bones. The subjects consisted of 15 females and 25 males with a mean age of 60.3 years. Spearman correlation analysis and Wilcoxon rank sum test was performed. The results were as follows. 1. There was statistically no correlation between the mandible and iliac bone in the values of corrected cortical width(CCW), cortical porosity(POR) in cortex, and total bone volume(TBV), mean trabecular plate thickness(MTPT), mean trabecular plate density(MTPD), and mean trabecular plate separation(MTPS) in trabecular bone. 2. Comparison of women and men over 60 years, men had statistically higher bone density than women except fir POR of buccal and lingual cortex, and WTPD of alveolar trabeculae in mandible. 3. There was statistically significant correlation between TBV of trabecular bone and CT No., but not between POR and CT No. in mandible. According to the results above, there was no correlation between mandible and iliac bone density and between mandibular bony density and age. Further studies are required to support the results. A more noninvasive method to be able to measure the bone density of mandible should be developed and it is necessary to accumulate data on the normal values of bone density of mandible according to age and sex. Further study should be carried out about QCT to measure mandibular bony density using QCT.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.892-895
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• 2005

This study investigated changes of mechanical characteristics in the trabecular and cortical bone of the lumbar vertebrae of the ovariectomised(OVX) rat. In previous researches, there were many studies for morphology of osteoporotic bones based on Micro-CT (Micro - Computed Tomography). However, there were few studies for detecting and tracking changes of mechanical characteristics in the trabecular bone and cortical bone of the lumbar vertebrae for the OVX rat. For this study, one female Sprague-Dawley rat was used: an OVX rat. The 4th lumbar of the OVX rat was utilized as a specimen. Detecting and tracking changes of mechanical characteristics could be investigated in the trabecular and cortical bone of the lumbar vertebrae for an OVX rat using In-vivo Micro-CT. An OVX rat was scanned at week 0 (just before surgery), at week 4, and week 8 after surgery. Micro finite element(${\mu}\;FE$) analysis was used to investigate mechanical characteristics in the trabecular and cortical bone of the lumbar vertebrae for an OVX rat.

• 대한소아치과학회지
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• 제31권2호
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• pp.228-235
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• 2004

하악 과두의 발달과 증식은 측두하악관절 부위의 생역학적 환경의 변화에 따라 변경될 수 있다. 이 부위에 전달되는 생역학적 하중은 섭취하는 음식물의 경도를 다르게 함으로써 변화시킬 수 있다. 이번 연구의 목적은 성장 중인 쥐에서 부드러운 음식물의 섭취에 의해 저작력을 변화시키는 것이 하악 과두의 해면골의 형태를 변화시킬 수 있는지 미세전산화 단층촬영을 이용하여 분석하는 것이었다. 생후 21일 된 C57BL/6 쥐 36마리를 무작위로 두 그룹으로 나누었다. 8주 동안 대조군의 쥐들은 일반적인 딱딱한 덩어리의 사료를, 실험군의 쥐들은 덩어리의 사료를 잘게 갈은 후 물과 섞어 부드럽게 만들어 먹였다. 또한 실험군의 쥐들의 하악 절치를 일주일에 두 번씩 잘라서 짧게 만들었다. 8주 후 모든 쥐들을 희생하여 우측 하악 과두를 준비하였다. 미세전산화 단층촬영과 삼차원 영상 분석프로그램을 이용하여 하악 과두 해면골의 bone volume(BV), bone surface(BS), total volume(TV) bone volume fraction(BV/TV), surface to volume ratio(BS/BV), trabecular thickness(Tb. Th.), structure model index(SMI)와 degree of anisotropy(DA)를 측정하고 이들 값으로부터 trabecular number(Tb. N.)와 trabecular separation (Tb. Sp.)을 계산하였다 미세전산화 단층영상을 얻은 후 하악 과두의 조직 표본을 만들었다. 연구 결과는 다음과 같았다. 1. Bone volume fraction(BV/TV), trabecular thickness(Tb. Th.)와 trabecular number(Tb. N.)가 대조군에 비해 부드러운 음식을 먹인 실험군에서 유의하게 감소되었다(p<0.05). 2. Trabecular separation(Tb. Sp.)은 부드러운 음식을 먹인 실험군에서 유의하게 증가하였다(p<0.05). 3. Surface to volume ratio(BS/BV), structure model index(SMI), degree of anisotropy (DA)는 두 군 사이에 유의한 차이를 보이지 않았다(p>0.05). 4. 조직 절편을 관찰한 결과, 부드러운 사료를 먹인 실험군에서 하악 과두의 연골층의 증식 층과 전체 두께가 상당히 감소하였다.

• 한국정보전자통신기술학회논문지
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• 제14권1호
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• pp.104-107
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• 2021

The orientation of trabeculae and porosity determine the wave propagation in cancellous bone. Wave propagation, as well as charge density and piezoelectricity, stimulate bone remodeling. Also, Charged ions in the fluid affect wave propagation in cancellous bone. But the trabecular struts' piezoelectricity does not change the waveform of cancellous bone. However, the underlying mechanism is unknown yet why trabecula struts' piezoelectricity does not change wave propagation through cancellous bone. Thus, we derived the governing equation indicating that trabecular struts' piezoelectric properties show that those do not affect wave propagation in cancellous bone.