• Geomechanics and Engineering
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• 제29권6호
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• pp.645-655
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• 2022

Granular columns have recently found widespread use in underground construction. The behaviour of granular columns under vertical loads has been extensively studied, specifically in relation to vertical load capacity obtained by bulging of the column body, including the behaviour after encasement of material. Determining the shear strength of loose soils reinforced with granular columns has received less attention. After the observations of lateral deformation near the toe of the embankment, attempts have been made to strengthen the lateral strength of granular columns. The purpose of this research is to look into the effects of different encasement conditions on the lateral load capacity of granular columns. This was accomplished by three-dimensional finite element analysis with FEM software. Various normal pressures and two different encasement configurations, namely single layer encasement and double layer encasement, with differing tensile strengths, were used in this study to determine their effect on lateral resistance. The failure envelope for a single column planted in loose sand was used to analyse the findings for three different granular column diameters, as well as the impact of different encasement conditions. According to the findings, the inclusion of a Granular Column enhanced the shear strength and overall stiffness of the loose sand bed, and the encasement of the Granular Column helped in deriving higher lateral resistance.

• Journal of the Korean Orthopaedic Association
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• 제55권6호
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• pp.457-471
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• 2020

Fingers are body parts with a complex structure and essential functions that are the most prone to trauma. The principle of treatment for finger fractures is to determine the balance between obtaining stable fracture fixation and early joint movement. Despite proper treatment, there are many cases of functional and cosmetic problems caused by stiffness or deformation as complications. This review article introduces the latest knowledge in the treatment of finger fractures focusing on fractures and dislocations around the interphalangeal joints, including joint surface damage, which is difficult to treat and leads to poor results. This article consists of fracture cases and describes the methods and solutions to address these complications.

• Clinics in Shoulder and Elbow
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• 제26권2호
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• pp.126-130
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• 2023

Background: Arm swing plays a role in gait by accommodating forward movement through trunk balance. This study evaluates the biomechanical characteristics of arm swing during gait. Methods: The study performed computational musculoskeletal modeling based on motion tracking in 15 participants without musculoskeletal or gait disorder. A three-dimensional (3D) motion tracking system using three Azure Kinect (Microsoft) modules was used to obtain information in the 3D location of shoulder and elbow joints. Computational modeling using AnyBody Modeling System was performed to calculate the joint moment and range of motion (ROM) during arm swing. Results: Mean ROM of the dominant elbow was 29.7°±10.2° and 14.2°±3.2° in flexion-extension and pronation-supination, respectively. Mean joint moment of the dominant elbow was 56.4±12.7 Nm, 25.6±5.2 Nm, and 19.8±4.6 Nm in flexion-extension, rotation, and abduction-adduction, respectively. Conclusions: The elbow bears the load created by gravity and muscle contracture in dynamic arm swing movement.

• Journal of the Korean Arthroscopy Society
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• 제12권3호
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• pp.211-216
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• 2008

Purpose: The frequency of foreign body in the knee joint is not as high, but it sometimes required wide or multiple arthrotomy in order to remove, which can baffle the surgeon in some ways. Our study is to evaluate for effectiveness of arthroscopic retrieval for intra-articular foreign body in the knee joint. Materials and Methods: The 22 patients(16 males, 6 females) had received arthroscopic foreign body retrieval in the knee joint from March 1983 to September 2006. The causes of foreign bodies of the knee joint were 7 of trauma (31.9%) related cases, 13 of surgery related cases (59.0%), 2 found during follow up after operation (8.1%) in pathologies of foreign body. Results: There were 15 of metal showed the most percentage (68.1%), 7 of non-metal (31.9%) in types of foreign bodies, and others included bullet, suture material, pencil lead, broken wire etc. All cases were used by arthroscopic techniques. All foreign bodies were removed easily and were showed no complication such as postoperative joint stiffness. Conclusion: Arthroscopic foreign body retrieval in the knee joint is effective surgery in terms of easy access to foreign body and less postoperative complication.

• Journal of the Korea Concrete Institute
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• 제19권5호
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• pp.623-630
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• 2007

Grouting materials are used for the unification of superstructural and substructural body like bridge seat (shoe) or machinery pedestal and e.t.c by filling their intercalary voids. Accordingly, grouting materials have been developed and used mainly with products of high strength because those materials are constructed specially in a part receiving large or impact load. In this situation, the structural body constructed by grouting materials with high stiffness-centered (caused by high strength) products is apt to cause brittle failure when receiving over a limit stress and to cause cracks according to cumulative fatigue by continuous and cyclic load. In addition, grouting materials are apt to cause cracks by using too much rapid hardening agents that give rise to high heat of hydration to maintain high strength at early age. In this study, to overcome these problems, cement type grouting materials including powder of waste tire and resin as elastic materials which aim to be more stable construction and to be improvement of mother-body's unification are developed and endowed with properties of high toughness and high durability add to existing properties of high flowability, non-shrinkage and high strength. Besides, this study contribute to of for green construction materials for being possible recycling industrial waste like waste tire and flyash. On the whole, seven type mixing conditions are tested and investigated to choose the best mixing condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제21권10호
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• pp.283-290
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• 2020

In this study, a floater was developed for a frame-type solar power plant. The floater supports the frame and the solar panels. A finite element analysis was performed to design its shape and thickness, and the floater was manufactured by a rotational molding method using linear low-density polyethylene. It was found that the floater did not cause collapse and it maintained its stiffness even at 4 times the maximum load of 322.7 kgf. To perform a long-term compression test, a weight-type load application device that uses gravity was designed and manufactured. The amount of compressive deformation was measured for 7 days, and a long-term deformation equation was obtained. Even under small loads, continuous deformation was observed. However, the 10-year deformation amount for a constant load of 100 kgf was predicted to be small at about 4.64 mm. As a result, it was found that the developed floater could be used in a solar power plant on a body of water.

• The Journal of Korean Physical Therapy
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• 제15권1호
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• pp.61-81
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• 2003

There can be little dissension that the ultimate goal of all physical therapy interventions with the elderly is to restore or maintain the highest level of function possible for the individual. Whenever physical therapists take on this challenge, they assist elders in maintaining their identities as competent adults. Advancing age is associated with profound changes in body composition, including increased fat mass, decreased fat-free mass(particularly muscle), decreased total body water and decreased bone density. Along with these changes in body compositions, and perhaps as a direct result of them, elderly people have lower energy needs, reduced strength and functional capacity and a greatly increased risk for such diseases as noninsulin-dependent diabetes mellitus and osteoporosis. Resistance training is considered a promising intervention for reversing the loss of muscle function and the deterioration of muscle structure that is associated with advanced age. This reversal is thought to result in improvements in functional abilities and health status in the elderly by increasing muscle mass, strength and power and by increasing bone mineral density. In the past couple of decades, many studies have examined the effects of Resistance training on risk factors for age-related diseases or disabilities. We have explored the positive and negative aspects of older adults' participation in resistance training programs. The benefits to older adults are reported to be increased strength, endurance, muscle capacity, and flexibility; more energy; and improved self-image and confidence. The negative aspects include some pain or stiffness and other nonspecific problems. The positive and negative aspects of resistance training are therefore very similar to those in younger populations. Scientific investigations over the past 10 years have demonstrated that resistance training can be safely and successfully implemented in older populations. Even the frail and very sick elderly can benefit and improve their quality of life. Proper design and progression of a resistance training program for older adults is vital to optimal benefits from resistance exercise. The results of data provided by this research on resistance training for health shows that there is enough existing evidence to conclude that resistance training, particularly when incorporated into a comprehensive fitness program, can offer substantial health benefits which can be obtained by persons of all ages. These benefits, including improvements in functional capacity, translate into an improved quality of life.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권6호
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• pp.19-26
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• 2021

The lattice structure is attracting attention from industry because of its excellent strength and stiffness, ultra-lightweight, and energy absorption capability. Despite these advantages, widespread commercialization is limited by the difficult manufacturing processes for complex shapes. Additive manufacturing is attracting attention as an optimal technology for manufacturing lattice structures as a technology capable of fabricating complex geometric shapes. In this study, a unit cell was formed using a three-dimensional coordinate method. The relative density relational equation according to the boundary box size and strut radius of the unit cell was derived. Simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC) with a controlled relative density were designed using modeling software. The accuracy of the equations for calculating the relative density proposed in this study secured 98.3%, 98.6%, and 96.2% reliability in SC, BCC, and FCC, respectively. A simulation of the lattice structure revealed an increase in compressive yield load with increasing relative density under the same cell arrangement condition. The compressive yield load decreased in the order of SC, BCC, and FCC under the same arrangement conditions. Finally, structural optimization for the compressive load of a 20 mm × 20 mm × 20 mm structure was possible by configuring the SC unit cells in a 3 × 3 × 3 array.

• Clinical and Experimental Pediatrics
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• 제50권6호
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• pp.549-555
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• 2007

Purpose : Pulse wave velocity (PWV) and ankle brachial index (ABI) are simple, non-invasive methods to assess arterial stiffness. These parameters are also known to be closely related to cardiovascular risk factors and diseases. The purposes of this study were to measure blood pressure, PWV, ABI in healthy Korean adolescents, set up their normal values and assess their correlations. Methods : Three hundred ninety two healthy adolescents (213 boys and 179 girls) underwent measurement of brachial ankle pulse wave velocity (baPWV), ABI, body mass index(BMI) and blood pressure from four extremities. Linear regression analysis was performed to reveal the correlations between PWV, ABI and independent variables. Results : Blood pressure and PWV were significantly higher in all extremities in males compared to females. Blood pressure of both brachial and ankle showed positive correlation with body weight, height, and BMI, whereas ABI showed no correlation with any of these indices. Conclusion : Blood pressure increases as body weight, height and BMI increases. PWV shows positive correlation with blood pressure. It will be helpful to predict the risks of cardiovascular diseases in adolescents.

• Clinical and Experimental Pediatrics
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• 제49권4호
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• pp.368-374
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• 2006

Purpose : The prevalence of obesity in children is increasing rapidly. Epidemiologic studies suggest that obesity induced atherosclerosis may start in childhood. We investigated whether obese children show early abnormalities of the arterial wall and endothelial dysfunction. Methods : Thirty-eight obese children(14-16 years old of age, male, body mass index $29.40{\pm}3.18kg/m^2$) and forty-five age and sex-matched healthy control children(body mass index $18.43{\pm}1.01kg/m^2$) were enrolled. Their carotid artery intima-media thickness(IMT) and brachial artery flowmediated dilation(FMD) response were measured by high-quality ultrasound system, and compliance, distensibility, stiffness index, incremental elastic modulus and wall stress were calculated by equation. In addition, we looked at the relations between these arterial features and metabolic cardiovascular risk factors. Results : The obese children had significantly increased IMT($0.52{\pm}0.09mm$ vs $0.40{\pm}0.07mm$, P< 0.001) and markedly impaired FMD($7.35{\pm}7.78$ percent vs $20.34{\pm}16.81$ percent, P<0.001) than the healthy controls. But the compliance and distensibility were lower, and the stiffness index, incremental elastic modules and wall stress were higher in the obese group than the control group, but not statistically significantly. Body mass index was highly associated with increased IMT(r=0.612, P<0.001) and reduced FMD(r=-0.414, P<0.001). Conclusion : We showed the deleterious effect of child obesity on both early functional and structural atherosclerotic markers. The ultrasonic findings will be used for screening and follow up markers to identify high-risk patients among obese children.