• Journal of Korean Foot and Ankle Society
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• v.22 no.4
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• pp.135-144
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• 2018

Acute lateral ankle sprain, which is the most common musculoskeletal injury, can be treated effectively with appropriate evidence-based initial care using PRICE (protection, rest, ice, compression, and elevation) and functional rehabilitation. Many systemic reviews reporting a high-level of evidence supporting the clinical usefulness and necessity of primary surgical repair for acute lateral ankle sprain have been insufficient. Regardless of the severity of ligament complex injuries, the surgical treatment for acute lateral ankle sprain without concomitant pathologies is not recommended and should be considered only in young professional athletes with complete ligament rupture (grade III) and severe instability.

• Steel and Composite Structures
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• v.38 no.1
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• pp.103-120
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• 2021

This research examines the eccentric compression performance of composite columns composed of recycled aggregate concrete (RAC)-filled square steel tube and profile steel. A total of 17 specimens on the composite columns with different recycled coarse aggregate (RCA) replacement percentage, RAC strength, width to thickness ratio of square steel tube, profile steel ratio, eccentricity and slenderness ratio were subjected to eccentric compression tests. The failure process and characteristic of specimens under eccentric compression loading were observed in detail. The load-lateral deflection curves, load-train curves and strain distribution on the cross section of the composite columns were also obtained and described on the basis of test data. Results corroborate that the failure characteristics and modes of the specimens with different design parameters were basically similar under eccentric compression loads. The compression side of square steel tube yields first, followed by the compression side of profile steel. Finally, the RAC in the columns was crushed and the apparent local bulging of square steel tube was also observed, which meant that the composite column was damaged and failed. The composite columns under eccentric compression loading suffered from typical bending failure. Moreover, the eccentric bearing capacity and deformation of the specimens decreased as the RCA replacement percentage and width to thickness ratio of square steel tube increased, respectively. Slenderness ratio and eccentricity had a significantly adverse effect on the eccentric compression performance of composite columns. But overall, the composite columns generally had high-bearing capacity and good deformation. Meanwhile, the mechanism of the composite columns under eccentric compression loads was also analysed in detail, and the calculation formulas on the eccentric compression capacity of composite columns were proposed via the limit equilibrium analysis method. The calculation results of the eccentric compression capacity of columns are consistent with the test results, which verify the validity of the formulas, and the conclusions can serve as references for the engineering application of this kind of composite columns.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.249-257
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• 1999

A three dimensional finite model of a human neck has been developed in an effort to study the mechanics of cervical spin while subjected to vertical impact. This model consisting of the vertebrae from C1 through C7 including posterior element and ligaments was constructed by 2mm thick transverse CT cross-sections and X-ray film taken at lateral side. Geometrical nonlinearity was also considered for the large deformation on the disc. ABAQUS package was used for calculation and its results were verified comparing with responses of a model under static loading condition with published in-vitro experimental data. There were more cervical fracture in the restrained (compression) mode than in the nonrestrained (flexion-compression and extension-compression) mode. Upper cervical(C1-C2) injuries were observed under compression-extension modes, while lower cervical injuries occurred undjer compression-flexion modes. Posterior ligament distraction without bony damage at the upper cervical spin(C1-C2) were observed secondary to C5-C7 trauma in compression-flexion modes.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.61-69
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• 2008

To examine the compression properties of structural members, the compression and bearing tests were conducted in parallel- and perpendicular-to-grain loading using domestic Japanese larch (Larix kaempferi (Lamb.) Carriere). Compression (bearing) properties with the length of a specimen and the contact length of the bearing plate were investigated, and deformations at each specimen length from the point of bearing force were measured to evaluate the effective end distance tabulated in the present practice (Korean Building Code). Compression (bearing) properties varied with the size of the bearing plate, and the end distance for dowel-type fastener taken into consideration of the specimen's deformation, for the safe design, should be applied with over 7 D.

• Structural Engineering and Mechanics
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• v.86 no.5
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• pp.687-704
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• 2023

This study aims to examine the structural response of glass fibre-reinforced polymer (Glass-FRP) reinforced geopolymer electronic waste aggregate concrete (GEWC) compression elements under axial compression for sustainable development. The research includes the fabrication of nine GEWC circular compression elements with different reinforcement ratios and a 3-D nonlinear finite element model using ABAQUS. The study involves a detailed parametric analysis to examine the impact of various parameters on the behavior of GEWC compression elements. The results indicate that reducing the vertical distance of glass-FRP ties improves the ductility of GEWC compression elements, and those with eight longitudinal rebars have higher axial load-carrying capacities. The finite element predictions were in good agreement with the testing results, and the put forwarded empirical model shows higher accuracy than previous models by involving the confinement effect of lateral glass-FRP ties on the axial strength of GEWC compression elements. This research work contributes to minimizing the carbon footprint of cement manufacturing and electronic waste materials for sustainable development.

• The Korean Journal of Emergency Medical Services
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• v.20 no.1
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• pp.7-15
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• 2016

Purpose: There are few studies on the quality of cardiopulmonary resuscitation (CPR) performed by a single rescuer using a bag-valve-mask device. The aim of this study is to compare CPR quality outcomes according to the rescuer's position or mask fixation grip method and to determine the optimal means of achieving therapeutic goals. Methods: The three CPR methods were defined as over-the-head, lateral-superior, and lateral-inferior, depending on the rescuer's position or mask fixation hand placement. CPR quality was estimated for 83 paramedic students who performed 5 minutes of CPR in a randomized sequence on a manikin using each of the three methods. Results: The over-the-head method showed no advantage for cardiac compression and ventilation quality, but minimized the rescuer's fatigue score. Conclusion: In contrast to previous studies or prevailing beliefs, the lateral-superior position is optimal for achieving therapeutic goals with moderate or minimal rescuer fatigue.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.61-70
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• 2005

This study investigated the spinal loads(L5/S1 disc compression and shear forces) predicted from four biomechanical models: one EMG model and three optimization models. Three objective functions used in the optimization models were to miminize 1) the cubed muscle forces : MF3, 2) the cubed muscle stress : MS3, 3) maximum muscle intensity : MI. Twelve healthy male subjects participated in the isometric voluntary exertion tests to six directions : flexion/extension, left/right lateral bending, clockwise/ counterclockwise twist. EMG signals were measured from ten trunk muscles and spinal loads were assessed at 10, 20, 30, 40, 50, 60, 70, 80, 90%MVE(maximum voluntary exertion) in each direction. Three optimization models predicted lower L5/S1 disc compression forces than the EMG model, on average, by 31%(MF3), 27%(MS3), 8%(MI). Especially, in twist and extension, the differences were relatively large. Anterior-posterior shear forces predicted from optimization models were lower, on average, by 27%(MF3), 21%(MS3), 9%(MI) than by the EMG model, especially in flexion(MF3 : 45%, MS3 : 40%, MI : 35%). Lateral shear forces were predicted far less than anterior-posterior shear forces(total average = 124 N), and the optimization models predicted larger values than the EMG model on average. These results indicated that the optimization models could underestimate compression forces during twisting and extension, and anterior-posterior shear forces during flexion. Thus, future research should address the antagonistic coactivation, one major reason of the difference between optimization models and the EMG model, in the optimization models.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.24 no.1
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• pp.77-83
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• 2018

Background: The purpose of this study is to investigate that effect of manual therapy using pelvic compression belt on hip abductor strength and balance ability in total knee replacement (TKR) patients. Methods: The subjects consisted of twenty two post-TKR patients. Participants were randomly assigned to a pelvic belt group (n=11) and a placebo group (n=11). All participants underwent manual therapy including range of motion exercise, soft tissue mobilization around knee joint, strengthening exercise (Quad set, SLR, sidelying hip abduction, standing hamstring curls, sitting knee extension, step-up, wall slide to $45^{\circ}$ knee flexion). Manual therapy was executed five times a week for 2 weeks. Outcome measures included hip abductor strength by using Biodex system 4 pro, anterior to posterior balance, medial to lateral balance, total balance by using Biodex balance system SD. Results: After the completion of the manual therapy, hip abductor strength was showed statistically significant improvements in pelvic belt group (p<.05). Anterior to posterior balance, medial to lateral balance, total balance were showed statistically significant improvements in pelvic belt group and placebo group (p<.05). There was a statistically significant difference between the two groups in hip abductor strength and there was no statistically significant difference in balance. Conclusions: This results suggest that manual therapy using pelvic compression belt has could be used for selective muscle activation of the hip abductor muscle and has useful in hip abductor strength and balance ability in TKR patients.

• Tunnel and Underground Space
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• v.32 no.3
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• pp.219-230
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• 2022

The Geo-Reservoir Experimental Analogue Technology (GREAT) cell was designed to recreate the thermal-hydro-mechanical conditions of deep subsurface in the laboratory. This apparatus can generate a polyaxial stress field using lateral loading elements, which rotate around the longitudinal axis of a sample and is capable of performing a fluid flow test for samples containing fractures. In the present study, numerical simulations were carried out for triaxial compression tests using the GREAT cell and the mechanical behavior of samples under different conditions of lateral loading was investigated. We simulated an actual case, in which triaxial compression tests were conducted for a polymer sample without fractures, and compared the results between the numerical analysis and experiment. The surface strain (circumferential strain) of the sample was analyzed for equal and non-equal horizontal confining pressures. The results of the comparison showed a good consistency. Additionally, for synthetic cases with a fracture, we investigated the effect of the friction and type of fracture surface on the deformation behavior.

• Journal of Trauma and Injury
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• v.18 no.2
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• pp.107-111
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• 2005

Backgrounds: To evaluate the effectiveness of conservative treatment in osteoporotic thoraco-lumbar compression fractures and to identify the factors influencing the progression of compression. Materials and Methods: From January 2003 to October 2004, Patients who were admitted to our hospital for osteoporotic thoraco-lumbar compression fractures were reviewed retrospectively with follow-up more than 12 months (ave. 14.6 months). With simple x-ray lateral view, we evaluate wedge compression ratio (WCR) and kyphotic angle (KA) at initial and final follow-up. We separate the patients into two groups baesed on the amount of progression of vertebral compression and evaluate a relation with BMD, vertebral fracture level, initial WCR, initial KA. All datas were statistically analyzed. Results: An average of T-score was -3.5 and the changes of KA between initial and final follow-up were average $3.5^{\circ}$. Compression of anterior column were progressed to 8.5%. The changes between initial and final WCR in Group I (N=24) was 17.8%, and Group II (N=18) was 3.3%. T-score in group I was -3.4 and group II was -3.8 (p=0.228). vertebral fracture level were 10 T12, 12 L1, 2 L2 in group I; 6 T12, 6 L1, 6 L2 in group II (p=0.156). Initail WCR was 0.74 in group I, 0.63 in group II, and there was statistical difference between two groups(p=0002). Initial kyphotic angle was $13.9^{\circ}$in group I, $16.2^{\circ}$in group II repectively (p=0.392). Conclusion: The conservative treatment with short-term bed rest and early embulation is effective and valuable method to patients who have osteoporotic thoraco-lumbar compression fractures. There was no statistical difference between two groups according to BMD, vertebral fracture level, KA. But in comparison with initail WCR between two groups, there was statistical difference. That means, in the case of small initial compression of anterior column, the progression of compression was bigger than else. In these patients, more strict use of appropriate brace and careful follow-up should be needed.