• Journal of Korean Medicine Rehabilitation
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• v.21 no.4
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• pp.87-96
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• 2011

Objectives: This study aims to systematically evaluate the effectiveness of Eastern-Western integrative medicine for musculoskeletal disorders compared with Eastern or Western Medicine. Methods: Systematic sea-mes of 9 major Korean databases were conducted for articles published up to July 2011. Searching keyword was "Integrative Medicine". Prospective studies dealt with musculoskeletal disorders by Eastern-Western integrative medicine were included. Quality assessment of included studies was evaluated by Cochrane risk of bias tool. Results: 470 studies in total were seamed, Amalg them 7 studies met our inclusion criteria(3 randomized controlled clinical trials, 2 non-randomized controlled trials and 2 uncontrolled clinical trials). Included studies dealt with lumbar pan(3), shoulder pain(2), pain after traffic injury(1), spinal compression fracture(1). Eastern-Western integrative medicine showed better or equal effect for the treatment of various muscloskeletal disorders compared with Eastern or Western medicine alone. Conclusions: There is very weak evidence for the effectiveness of Eastern-Western integrative medicine for musculoskeletal disorders compared with Eastern or Western medicine alone. Well designed randomized controlled trials with rigorous methodology are needed to evaluate the effectiveness of Eastern-Western integrative medicine objectively in the future.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.4
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• pp.42-50
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• 2008

Various researches to reduce weight of a vehicle are achieving. One of these researches is tendencious to manufacture the hollow piston rod using friction welding instead of solid one of the vehicle shock absorber. This study deals with the friction welding of SM45C to SM20C-pipe that is used normally in the vehicle shock absorber. The friction time was variable conditions under the conditions of spindle revolution of 2,000rpm, friction pressure of 55MPa, upset pressure of 75MPa, and upset time of 2.0seconds. Under these conditions, the microstructure of weld interface, tensile fracture surface and mechanical tests of friction weld were studied and so the results were as follows. When the friction time was l.5seconds under the conditions, the maximum tensile strength of the friction weld happened to be 837MPa, which is 113% of SM20C's tensile strength and 97% of SM45C's. The optimal welding conditions were n=2,000rpm, $P_1=55MPa$, $P_2=75MPa$, $t_1=1.5sec$, $t_2=2.0sec$ when the total upset length is 1.7mm.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.65-70
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• 2008

This study deals with the friction welding of SKH55 and SM45C; The friction time was variable conditions under the conditions of spindle revolution 2,000rpm, friction pressure of 190MPa, upset pressure of 270MPa and upset time of 2.0 seconds. Under these conditions, the microstructure of weld interface, tensile fracture surface and mechanical tests were studied, and so the results were as follows. 1. When the friction time is 1.0 seconds, the tensile strength of friction welds was 926MPa, which is around as much as 84% of the tensile strength of base metal(SKH55), the bending strength of friction welds was 1,542MPa, which is around as much as 80% of the bending strength of base metal(SKH55), the shear strength of friction welds was 519MPa, which is around as much as 70% of the shear strength of base metal(SKH55). 2 According to the hardness test, the hardness distribution of the weld interface was formed from 964Hv to 254Hv. HAZ(Heat Affected Zone) was formed from the weld interface to 1.5mm of SKH55 and 2mm of SM45C.

• Nuclear Engineering and Technology
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• v.19 no.3
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• pp.169-179
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• 1987

The change of material J-R (J-T) curve with crack extension and J-calculation method was investigated to give experimental and analytical method for reliable J-R (J-T) curve, which was adapted recently as a tool for instability analysis of Nuclear Pressure Vessel. Experiments were carried out by Single Specimen Unloading Compliance Method using 1/2"T, Compact-Tension Type fracture mechanic specimens which were the same size and material as domestic nuclear pressure vessel material surveillance specimens. The results revealed that crack extension up to 25~30% of initial uncracked ligament and JD (Deformation theory J) calculation method, currently being used in NUREG-0744, could give rather reliable material J-R (J-T) curve than the small crack extension and JM (Modified J) calculation method. But as JM results more or less higher J at instability, the application of JM should be considered regarding to the problem of power plant availability.lity.

• Journal of Trauma and Injury
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• v.21 no.1
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• pp.15-21
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• 2008

Purpose: National Emergency X-Radiography Utilization Study (NEXUS) criteria and the Canadian Cervical Spine rule (CCR) are commonly used in cervical trauma patients to determine whether a plain cervical X-ray should be performed. However, plain cervical X-rays are so inaccurate that cervical spine computed tomography (CT) is often considered as a screening test. We studied the usefulness of the NEXUS criteria and the CCR for determining the need for a CT evaluation in the emergency department (ED). Methods: This prospective observational study was conducted from January 2007 to March 2008. Plain X-ray and CT scans of the cervical spine were performed on blunt trauma patients with neck pain. The relevancy of CT was examined using the NEXUS criteria and the CCR. Sensitivity, specificity, positive predicted value, and negative predicted value analyses were performed to diagnose the cervical spine injury. Results: During the study period, 284 patients were enrolled in this study. The sensitivity, specificity, positive predicted value, and negative predicted value of the NEXUS criteria were 87.5%, 1.1%, 5.0%, and 60.0% respectively, while those of the CCR were 87.5%, 8.2%, 5.3%, and 91.6%. There were two missed fracture cases when the NEXUS criteria and the CCR were applied independently, however, no cases were missed when both were applied. Conclusion: This study suggests the NEXUS and the CCR in combination can be used as a guide to CT evaluation for cervical spine injury in the ED.

• Journal of Korean Neurosurgical Society
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• v.29 no.3
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• pp.365-371
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• 2000

Objectives : To describe a technique for percutaneous vertebroplasty of osteoporotic vertebral body compression fractures and to report preliminary results of its use. Methods : The technique was used over a 8-month period in 9 patients with 10 painful vertebral fractures. The technique involves percutaneous puncture of the involved vertebrae with a Jamshidi needle via a transpedicular approach followed by injection of polymethylmethacrylate(PMMA) into the vertebral body. Results : The procedure was technically successful in all patients, with an average injection amount of 5.9 cc per vertebral body. One patient complained of flank pain postoperatively in spite of improvement in back pain caused by the fractured vertebra. Remaining eight patients reported significant pain relief early after treatment. The patients were followed up for 3 to 15 months(average 7.2 months) and demonstrated no recurrence of pain or aggravation of deformity. Conclusion : Vertebroplasty appears to be a valuable tool in the treatment of painful osteoporotic vertebral fractures, providing acute pain relief and early mobilization in appropriate patients. However, it needs to have more extensive prospective clinical study to confirm its definitive role in the management of this condition.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.221-230
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• 2019

In this paper, shear behavior of non-persistent joint surrounded in concrete and gypsum layers has been investigated using experimental test and numerical simulation. Two types of mixture were prepared for this study. The first type consists of water and gypsum that were mixed with a ratio of water/gypsum of 0.6. The second type of mixture, water, sand and cement were mixed with a ratio of 27%, 33% and 40% by weight. Shear behavior of a non-persistent joint embedded in these specimens is studied. Physical models consisting of two edge concrete layers with dimensions of 160 mm by 130 mm by 60 mm and one internal gypsum layer with the dimension of 16 mm by 13 mm by 6 mm were made. Two horizontal edge joints were embedded in concrete beams and one angled joint was created in gypsum layer. Several analyses with joints with angles of $0^{\circ}$, $30^{\circ}$, and $60^{\circ}$ degree were conducted. The central fault places in 3 different positions. Along the edge joints, 1.5 cm vertically far from the edge joint face and 3 cm vertically far from the edge joint face. All samples were tested in compression using a universal loading machine and the shear load was induced because of the specimen geometry. Concurrent with the experiments, the extended finite element method (XFEM) was employed to analyze the fracture processes occurring in a non-persistent joint embedded in concrete and gypsum layers using Abaqus, a finite element software platform. The failure pattern of non-persistent cracks (faults) was found to be affected mostly by the central crack and its configuration and the shear strength was found to be related to the failure pattern. Comparison between experimental and corresponding numerical results showed a great agreement. XFEM was found as a capable tool for investigating the fracturing mechanism of rock specimens with non-persistent joint.

• Korean Journal of Radiology
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• v.21 no.7
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• pp.891-899
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• 2020

Objective: To assess the diagnostic performance of a deep learning-based algorithm for automated detection of acute and chronic rib fractures on whole-body trauma CT. Materials and Methods: We retrospectively identified all whole-body trauma CT scans referred from the emergency department of our hospital from January to December 2018 (n = 511). Scans were categorized as positive (n = 159) or negative (n = 352) for rib fractures according to the clinically approved written CT reports, which served as the index test. The bone kernel series (1.5-mm slice thickness) served as an input for a detection prototype algorithm trained to detect both acute and chronic rib fractures based on a deep convolutional neural network. It had previously been trained on an independent sample from eight other institutions (n = 11455). Results: All CTs except one were successfully processed (510/511). The algorithm achieved a sensitivity of 87.4% and specificity of 91.5% on a per-examination level [per CT scan: rib fracture(s): yes/no]. There were 0.16 false-positives per examination (= 81/510). On a per-finding level, there were 587 true-positive findings (sensitivity: 65.7%) and 307 false-negatives. Furthermore, 97 true rib fractures were detected that were not mentioned in the written CT reports. A major factor associated with correct detection was displacement. Conclusion: We found good performance of a deep learning-based prototype algorithm detecting rib fractures on trauma CT on a per-examination level at a low rate of false-positives per case. A potential area for clinical application is its use as a screening tool to avoid false-negative radiology reports.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.281-293
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• 2011

We investigated the causes and characteristics of a landslide at Hwangryeong Mountain, Busan, based on aerial photos, annual precipitation data, rock fracture patterns, and geomorphic features using GIS Software, and a statistical analysis of tilted trees. The analyzed slope shows evidence of a previous slope failure event and the possibility of future failures. Although the NW-SE trending slope was relatively stable until 1975, a large-scale slope failure occurred between 1975 and 1985 due to complex factors, including favorably oriented geologic structures, human activity, and heavy rain. This indicates that a detailed study of geologic structures, slope stability, and rainfall characteristics is important for slope cuttings that could be a major factor and cause of urban landsliding events. The statistic analysis of tilted trees shows a slow progressive creeping type of mass wasting with rock falls oblique to the dip of the slope, with the slope having moved towards the west since 1985. A concentration of tree tilting has developed on the northwestern part of the slope, which could reach critical levels in the future. The analysis of deformed trees is a useful tool for understanding landslides and for predicting and preventing future landslide events.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.87-101
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• 2012

Bruxism is extensively defined as a diurnal or nocturnal parafunctional habit of tooth clenching or grinding. The etiology of bruxism may be categorized as central factors or peripheral factors and according to previous research results, central factors are assumed to be the main cause. Bruxism may cause tooth attrition, cervical abfraction, masseter hypertrophy, masseter or temporalis muscle pain, temporomandibular joint arthralgia, trismus, tooth or restoration fracture, pulpitis, trauma from occlusion and clenching in particularly may cause linea alba, buccal mucosa or tongue ridging. An oral appliance, electromyogram or polysomnogram is used as a tool for diagnosis and the American Sleep Disorders Association has proposed a clinical criteria. However the exact etiology of bruxism is yet controversial and the selection of treatment should be done with caution. When the rate of bruxism is moderate or greater and is accompanied with clinical symptoms and signs, treatment such as control of dangerous factors, use of an oral appliance, botulinum toxin injection, pharmacologic therapy and biofeedback therapy may be considered. So far, oral appliance treatment is known to be the most rational choice for bruxism treatment. For patients in need of esthetic correction of hypertrophic masseters, as well as bruxism treatment, botulinum toxin injection may be a choice.