• Title/Summary/Keyword: biomechanics

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A Novel Kinematic Design of a Knee Orthosis to Allow Independent Actuations During Swing and Stance Phases (회전기 및 착지기 분리 구동을 가능케 하는 새로운 무릎 보장구의 기구부 설계)

  • Pyo, Sang-Hun;Kim, Gab-Soon;Yoon, Jung-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.8
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    • pp.814-823
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    • 2011
  • Nowadays many neurological diseases such as stroke and Parkinson diseases are continually increasing. Orthotic devices as well as exoskeletons have been widely developed for supporting movement assistance and therapy of patients. Robotic knee orthosis can compensate stiff-knee gait of the paralyzed limb and can provide patients consistent assistance at wearable environments. With keeping a robotic orthosis wearable, however, it is not easy to develop a compact and safe actuator with fast rotation and high torque for consistent supports of patients during walking. In this paper, we propose a novel kinematic model for a robotic knee orthosis to drive a knee joint with independent actuation during swing and stance phases, which can allow an actuator with fast rotation to control swing motions and an actuator with high torque to control stance motions, respectively. The suggested kinematic model is composed of a hamstring device with a slide-crank mechanism, a quadriceps device with five-bar/six-bar links, and a patella device for knee covering. The quadriceps device operates in five-bar links with 2-dof motions during swing phase and is changed to six-bar links during stance phase by the contact motion to the patella device. The hamstring device operates in a slider-crank mechanism for entire gait cycle. The kinematics and velocity/force relations are analyzed for the quadriceps and hamstring devices. Finally, the adequate actuators for the suggested kinematic model are designed based on normal gait requirements. The suggested kinematic model will allow a robotic knee orthosis to use compact and light actuators with full support during walking.

Animals Physical Therapy (동물물리치료)

  • Kim, Jin-Ung;Bae, Soo-Chan
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.8 no.2
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    • pp.45-55
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    • 2002
  • This article review the animals physical therapy. It is so called veterinary physical therapy. The animals physical therapist is working to physical therapy for animals in veterinary clinical field. The veterinary medicine has not veterinary rehabilitation medicine or physical therapy for animals, also physical therapy field in Korea. So, This research will explain about animals physical therapy of Korea and other countries' by journals and internet information and suggest the future of the animals physical therapist. Finally, The veterinary physical therapy is not used to veterinary clinical field in now. But, The veterinary physical therapy will desire to the view of medical serve and economy by the host of animals and clinical veterinarian the future. Animal physical therapy is a new and rapidly developing field of health care for animals. The benefits of physical therapy have long been recognized in humans. More recently, work in the veterinary field has shown the same benefits of physical therapy to be true for animal patients. Performing orthopaedic or neurological surgery, or fitting a human patient with a cast or splint, and then discharging the patient is an outdated approach. In such cases, physical therapy is clearly warranted. Similarly, recent research has shown that post-surgical rehabilitation and therapy after injuries significantly improves the functional outcomes for animals. Physical Therapy is a healthcare profession directed at evaluating, restoring and maintaining physical function and movement. Working with the owner, veterinarian and often other healthcare professionals, a physiotherapist helps your animal to achieve and maintain optimal health and well-being. Equipped with a specialized university Bacheloriate education and intensively educated in Anatomy, Physiology, Biomechanics, Histology, Neurology, and Pathology, PT's are able to assess, diagnose and treat movement and function. Physical Therapy, Sports Medicine and Rehabilitation are recognized sciences applied to both humans and animals. The goals of physiotherapy are to relieve pain, restore range of motion/movement, improve function, prevent injuries and expand the physical potential of the patient. Once in the field, physical therapists actively continue their education to keep up to date on the latest treatments and technologies. Via continuing education courses, physiotherapists can learn how to apply their unique and specialized knowledge to other animal species.

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Effects of Balance and Kinematic Factors on Archery Score during Archery Shooting (양궁 슈팅 시 균형성과 운동학적 요인이 양궁 점수에 미치는 영향)

  • An, Hyung-Seung
    • Journal of the Korea Convergence Society
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    • v.9 no.5
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    • pp.239-246
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    • 2018
  • In this study, we analyzed the balance of the both legs and the kinematic analysis of the upper limb segments and joints during archery shooting and compared the differences according to the scores. 9 K-university elite archery athletes participated. Each archer was asked to shoot 3-shots and 5-ends on a 122 cm target at a distance of 70 m. Seven infrared cameras (Qualisys, sweden) and two force plates (Kistler, Switerland) were used to calculate the upper limb segments and joint movements and the center of pressure (COP). When the archers shot 8 points, range of motion of elbow joint angle on drawing-arm and mediolateral COP range of motion on the left foot were larger than when 9-10 points were shot (p<.05). In order to maintain a high score in the archery game, constant balance is required, and the balance of the left foot supporting the bow during the shooting is an important factor. In addition, minimizing elbow joint movement of the drawing-arm supporting the bow will help stabilized shooting.

Three-dimensional optimization and sensitivity analysis of dental implant thread parameters using finite element analysis

  • Geramizadeh, Maryam;Katoozian, Hamidreza;Amid, Reza;Kadkhodazadeh, Mahdi
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.44 no.2
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    • pp.59-65
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    • 2018
  • Objectives: This study aimed to optimize the thread depth and pitch of a recently designed dental implant to provide uniform stress distribution by means of a response surface optimization method available in finite element (FE) software. The sensitivity of simulation to different mechanical parameters was also evaluated. Materials and Methods: A three-dimensional model of a tapered dental implant with micro-threads in the upper area and V-shaped threads in the rest of the body was modeled and analyzed using finite element analysis (FEA). An axial load of 100 N was applied to the top of the implants. The model was optimized for thread depth and pitch to determine the optimal stress distribution. In this analysis, micro-threads had 0.25 to 0.3 mm depth and 0.27 to 0.33 mm pitch, and V-shaped threads had 0.405 to 0.495 mm depth and 0.66 to 0.8 mm pitch. Results: The optimized depth and pitch were 0.307 and 0.286 mm for micro-threads and 0.405 and 0.808 mm for V-shaped threads, respectively. In this design, the most effective parameters on stress distribution were the depth and pitch of the micro-threads based on sensitivity analysis results. Conclusion: Based on the results of this study, the optimal implant design has micro-threads with 0.307 and 0.286 mm depth and pitch, respectively, in the upper area and V-shaped threads with 0.405 and 0.808 mm depth and pitch in the rest of the body. These results indicate that micro-thread parameters have a greater effect on stress and strain values.

Effects of Walking Speed on Foot Joint Motion and Peak Plantar Pressure in Healthy Subjects (정상인에서 보행속도가 발관절의 관절각과 발바닥 최대 압력 분포에 미치는 영향)

  • Park, Kyung-Hee;Kwon, Oh-Yun;Kim, Young-Ho
    • Physical Therapy Korea
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    • v.10 no.1
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    • pp.77-95
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    • 2003
  • Many factors affect foot and ankle biomechanics during walking, including gait speed and anthropometric characteristics. However, speed has not been taken into account in foot kinematics and kinetics during walking. This study examined the effect of walking speed on foot joint motion and peak plantar pressure during the walking phase. Eighty healthy subjects (40 men, 40 women) were recruited. Maximal dorsiflexion and excursion were measured at the first metatarsophalangeal joints during walking phase at three different cadences (80, 100, and 120 step/min) using a three dimensional motion analysis system (CMS70P). At the same time, peak plantar pressure was investigated using pressure distribution platforms (MatScan system) under the hallux heads of the first, second, and third metatarsal bones and heel. Maximal dorsiflexion and excursion and excursion at the ankle joint decreased significantly with increasing walking speed. Peak plantar pressure increased significantly under the heads of the first of the first, second, and third metatarsal bones, and heel with increasing walking speed: three was no change under the hallux. There were no significant changes in maximal dorsiflexion or excursion at the first metatarsophalangeal joint. The results show that walking speed should be considered when comparing gait parameters. The results also suggest that slow walking speeds may decrease forefoot peak plantar pressure in patients with peripheral neuropathy who have a high risk of skin breakdown under the forefoot.

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Prediction of Cement Volume for Vertebroplasty Based on Imaging and Biomechanical Results

  • Lee, Sung-Jae;Tack, Gye-Rae;Lee, Seung-Yong;Jun, Bong-Jae;Lim, Do-Hyung;Shin, Jung-Woog;Kim, Jeong-Koo;Shin, Kyu-Chul
    • Journal of Mechanical Science and Technology
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    • v.15 no.7
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    • pp.1041-1050
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    • 2001
  • Control of bone cement volume (PMMA) may be critical for preventing complications in vertebroplasty, the percutaneous injection of PMMA into vertebra. The purpose of this study was to predict the optimal volume of PMMA injection based on CT images. For this, correlation between PMMA volume and textural features of CT images was examined before and after surgery to evaluate the appropriate PMMA amount. The gray level run length analysis was used to determine the textural features of the trabecular bone. Extimation of PMMA volume was done using 3D visualization with semi-automatic segmentation on postoperative CT images. Then, finite element (FE) models were constructed based on the CT image data of patients and PMMA volume. Appropriate material properties for the trabecular bone were assigned by converting BMD to elastic modulus. Structural reinforcement due to the changes in PMMA volume and BMD was assessed in terms of axial displacement of the superior endplate. A strong correlation was found between the injected PMMA volume and the area of the intertrabecular space and that of trabecular bone calculated from the CT images (r=0.90 and -0.90, respectively). FE results suggested that vertebroplasty could effectively reinforce the osteoporotic vertebra regardless of BMD or PMMA volume. Effectiveness of additional PMMA injection tended to decrease. For patients with BMD well lower than 50mg/ml, injection of up to 30% volume of the vertebral body is recommended. However, less than 30% is recommended otherwise to avoid any complications from excessive PMMA because the strength has already reached the normal level.

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A Study of Fiber-Reinforced Material Models for the Mechanical Characteristics of Human Annulus Fibrosus (인체의 윤상인대의 역학적 특성 모사를 위한 섬유 강화 모델에 관한 연구)

  • Lim, Jun-Taek;Choi, Deok-Kee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.6
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    • pp.619-628
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    • 2011
  • Human soft tissues, including muscles, ligaments, skin, and blood vessels, are an interesting subject because damage to them can be observed in everyday life. Besides the lack of available experimental data and the large deformation upon loading, the anisotropic and compressible nature of annulus fibrosus makes it more difficult to find a simple material model. A fiber-reinforced hyperelastic material model is used to determine the stress-strain curves upon uniaxial loading. The energy potential function for annulus fibrosus is composed of three different parts: matrix, fibers, and matrix-fiber interaction, which accounts for the angles between two families of fibers. In this paper, two different types of energy potential function for the matrix are considered, and are inserted into the fiber-reinforced model. The calculated results are compared with the Neo-Hookean model and experimental data, and reasonable agreement is observed overall.

Effects of Dietary from Safflower Bud on the Osteoporosis in Ovariectomized Rats

  • Lim, Seul Ki;Kim, Dong Il;Park, Min Jung;Choi, Joo Hee;Kim, Young Kuk;Lee, An Chul;Choi, Mi Young;Park, Soo Hyun
    • Biomedical Science Letters
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    • v.20 no.3
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    • pp.156-161
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    • 2014
  • It has been reported that safflower seeds have preventive effects against osteoporosis. Recently, safflower buds (SB) were found to have more useful functional ingredients than safflower seeds. In the current study, we evaluated the anti-osteoporosis effects of SB diet in ovariectomized (OVX) rats. The rats were divided into five groups; sham operated group, OVX alone group, OVX plus $17{\beta}$-estradiol ($E^2$ $10{\mu}g/kg$, i.p.) and OVX plus SB diet feeding group (0.3% or 1%). Feeding of SB diet (0.3% or 1%) to OVX rats markedly increased bone mineral density (BMD) of femurs, compared to the OVX group. The OVX rats exhibited a marked increase in trabecular separation (Tb.Sp) and this change was inhibited by the feeding of SB diet, similar to that seen with OVX+E2 group. Moreover, feeding of SB diet to OVX rats decreased the markers of bone turnover, including osteocalcin and alkaline phosphatase (ALP). These results suggest that SB extract has a bone sparing effect in OVX-induced trabecular bone loss and prevents deterioration of bone microarchitecture by suppressing the rate of bone turnover. Therefore, SB may be useful for preserving bone mass and structure in estrogen deficient women with a potential role in reducing postmenopausal osteoporosis.

Liraglutide Inhibits the Apoptosis of MC3T3-E1 Cells Induced by Serum Deprivation through cAMP/PKA/β-Catenin and PI3K/AKT/GSK3β Signaling Pathways

  • Wu, Xuelun;Li, Shilun;Xue, Peng;Li, Yukun
    • Molecules and Cells
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    • v.41 no.3
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    • pp.234-243
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    • 2018
  • In recent years, the interest towards the relationship between incretins and bone has been increasing. Previous studies have suggested that glucagon-like peptide-1 (GLP-1) and its receptor agonists exert beneficial anabolic influence on skeletal metabolism, such as promoting proliferation and differentiation of osteoblasts via entero-osseous-axis. However, little is known regarding the effects of GLP-1 on osteoblast apoptosis and the underlying mechanisms involved. Thus, in the present study, we investigated the effects of liraglutide, a glucagon-like peptide-1 receptor agonist, on apoptosis of murine MC3T3-E1 osteoblastic cells. We confirmed the presence of GLP-1 receptor (GLP-1R) in MC3T3-E1 cells. Our data demonstrated that liraglutide inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as detected by Annexin V/PI and Hoechst 33258 staining and ELISA assays. Moreover, liraglutide upregulated Bcl-2 expression and downregulated Bax expression and caspase-3 activity at intermediate concentration (100 nM) for maximum effect. Further study suggested that liraglutide stimulated the phosphorylation of AKT and enhanced cAMP level, along with decreased phosphorylation of $GSK3{\beta}$, increased ${\beta}-catenin$ phosphorylation at Ser675 site and upregulated nuclear ${\beta}-catenin$ content and transcriptional activity. Pretreatment of cells with the PI3K inhibitor LY294002, PKA inhibitor H89, and siRNAs GLP-1R, ${\beta}-catenin$ abrogated the liraglutide-induced activation of cAMP, AKT, ${\beta}-catenin$, respectively. In conclusion, these findings illustrate that activation of GLP-1 receptor by liraglutide inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation through $cAMP/PKA/{\beta}-catenin$ and $PI3K/Akt/GSK3{\beta}$ signaling pathways.

A Study on Kinematic Analysis of Trunk and Lower Extremities in Stance Phase of Walking according to Turning Direction (보행 방향 전환 시 입각기 하지 및 체간의 운동형상학적 분석)

  • Oh, Tae-Young
    • The Journal of Korean Physical Therapy
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    • v.25 no.2
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    • pp.88-95
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    • 2013
  • Purpose: The purpose of this study was to conduct an analysis of kinematics of lower extremities and trunk in stance phase of walking according to turning direction. Methods: Ten university students (five male, five female) who were in their 20s (mean age was 20.6 years old) participated in this study. Participants did not have participants did not have any problem with skeletal muscular system. We used the "Qualisys motion capture system" for analysis of trunk and lower extremity movement in stance phase of walking according to turning direction. We collected data while subjects walked a distance of 10 m, and at the 6 m line, subjects were required to turn to the left side and the right leg was positioned in stance phase and the left leg was positioned in swing. For data analysis, the SPSS for Windows ver. 20.0 statistics program was used in performance of one way analysis of variance according to turning direction. Results: Significant difference of trunk and lower extremities was observed for turning direction according to walking cycle (p<0.05). Upper trunk movement showed a greater increase at three dimensions than lower trunk, and in heel off phase, pelvic movement showed a greater increase than lower trunk (p<0.05). In 45 degree and 90 degrees of turning direction, all movements of trunk and lower extremities were significantly different among three events of stance phase (p<0.05). Conclusion: We suggest that three-dimensional movement analysis of trunk and lower extremities during turning movement was very important in order to indicate increasing balance or walking ability for people with impaired movement or walking.