• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.44-52
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• 2009

Purpose: We assessed the radiographic and clinical results of one surgeon's experience treating proximal humerus fractures with a locked proximal humeral plate. Materials and Methods: Twenty patients with unstable proximal humerus fractures were treated with a locking compression plate between February 2005 and September 2007. The average age of the patients was 60.6 years, and the average postoperative follow-up period was 22.3 months. The clinical results were evaluated using the Constant and DASH scores. The radiologic results were evaluated by the Paavolainen method, which measures the neck shaft angle and humeral head height. Results: At the last follow-up examination, the mean Constant score was 75.3 and 15 cases (75%) had excellent or good results; the mean DASH score was 16.4. The mean neck shaft angle was $137.1^{\circ}$, and 19 cases (95%) had good results by the Paavolainen method. There was one delayed union, malunion, and screw loosening. Conclusion: The patients treated with a locking compression plate had relatively good clinical and radiologic results, and a low complication rate. Moreover, the patients could exercise earlier due to good reduction and initial stability. Treatment of unstable proximal humerus fractures with a locking compression plate is a reliable method.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.111-125
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• 2022

Since landslide can cause huge damages to many facilities, close characterization of slopes is needed for appropriate reinforcements for the unstable ones in order to prevent the damages. Geophysical surveys, which can characterize a large area at a relatively low cost without disturbing slopes, have been widely employed for the assessment of slope stability in other countries. However, only conventional direct investigation methods are mainly used in Korea. In this paper, we analyzed various cases, which evaluated slope stabilities by characterizing slopes using geophysical exploration. First, we introduced changes in geophysical properties due to unstable media of slope like fracture location, fracture connectivity and distribution of groundwater level, and subsequently discussed the applicability of geophysical methods to the detection of the changes; the methods include electrical resistivity survey, seismic survey, self-potential survey, induced polarization survey and ground penetrating radar. Based on this description, we analyzed how geophysical surveys were performed on various slopes.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.295-304
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• 2011

The first step in improving our understanding of uncertainties suclt as rock mass strength parameters and deformation modulus in rock masses around high-level radioactive waste disposal repositories, for improved safety, is to study the process of crack development in intact rock. Therefore, in this study, the fracture process and crack development were examined in samples of KURT granite taken from the KAERI Underground Research Tunnel (KURT), based on acoustic emission (AE) and moment tensor analysis. The results show that crack initiation, coalescence, and unstable crack occurred at rock uniaxial compressive strengths of 0.45, 0.73, and 0.84, respectively. In addition, moment tensor analysis indicated that during the early stage of loading, tensile cracks were predominant. With increasing applied stress, the number of shear cracks gradually increased. When the applied stress exceeded the stress level required for crack damage, unstable shear cracks which directly result in failure of the rock were generated along the failure plane.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.2
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• pp.115-120
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• 2009

Purpose: To evaluate the outcomes of three different surgical approaches in treating a distal radius fracture with dorsal communition. Materials and Methods: From April, 2006 to May, 2009, 49 patients over age of 60years old with unstable dorsal communition distal radius fracture were analyzed. We compared maintainability of reduction by radiological follow-up observations and clinical outcomes using Mayo wrist scores. One-Way ANOVA test was performed to examine the statistical correlation between the methods. Results: All three approaches provided satisfactory post-op reduction results. However, follow-up observations showed significant loss of reduction in the external fixation only group compared to the added bone graft group and the volar anatomical locking plate group (P<0.05). Mayo wrist score was indifferent between the three groups. Conclusion: Treatment of a distal radius fracture with severe dorsal communition using an external fixation only appears to be insufficient in maintaining reduction of a cancellous bone defect.

• Geomechanics and Engineering
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• v.8 no.4
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• pp.541-557
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• 2015

This research aims to analyze the fracture coalescence characteristics of brittle sandstone specimen ($80{\times}160{\times}30mm$ in size) containing various flaws (a single fissure, double squares and combined flaws). Using a rock mechanics servo-controlled testing system, the strength and deformation behaviours of sandstone specimen containing various flaws are experimentally investigated. The results show that the crack initiation stress, uniaxial compressive strength and peak axial strain of specimen containing a single fissure are all higher than those containing double squares, while which are higher than those containing combined flaws. For sandstone specimen containing combined flaws, the uniaxial compressive strength of sandstone increase as fissure angle (${\alpha}$) increases from $30^{\circ}$ to $90^{\circ}$, which indicates that the specimens with steeper fissure angles can support higher axial capacity for ${\alpha}$ greater than $30^{\circ}$. In the entire deformation process of flawed sandstone specimen, crack evolution process is discussed detailed using photographic monitoring technique. For the specimen containing a single fissure, tensile wing cracks are first initiated at the upper and under tips of fissure, and anti-tensile cracks and far-field cracks are also observed in the deformation process; moreover anti-tensile cracks usually accompanies with tensile wing cracks. For the specimen containing double squares, tensile cracks are usually initiated from the top and bottom edge of two squares along the direction of axial stress, and in the process of final unstable failure, more vertical splitting failures are observed in the ligament region. When a single fissure and double squares are formed together into combined flaws, the crack coalescence between the fissure tips and double squares plays a significant role for ultimate failure of the specimen containing combined flaws.

• Journal of Yeungnam Medical Science
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• v.5 no.1
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• pp.61-67
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• 1988

The treatment of tibial shaft fracture has become one of the most controversial subjects in orthopedic surgery. Comminuted, segmental and rotationally unstable fractures or bone defect at fracture site have problems of the fixation. The interlocking nail solve these problems. We have experienced 8 cases of the tibial shaft fractures treated with interlocking nail from 1986 to 1988. Authors analysed these cases and our own clinical study. The results were as follows. 1. The average bone union rate was about 15 weeks. 2. The interval between operation and crutch walking was 4:3 weeks. 3. The merits of this operation were the short hospitalization and early adaptation of social activity. 4. The advantage is be able to do early ambulation without following muscular atrophy or joint stiffness. 5. The results were assessed on clinical examination and radiographic appearance by Hamza et al. An excellent results were 7 cases and good result was 1 case.

• Journal of the Korean Society for Railway
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• v.12 no.1
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• pp.16-24
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• 2009

In this study, fatigue crack growth rate of a cracked railway bogie frame under variable amplitude loading is predicted by applying linear elastic fracture mechanics. For this purpose, we find the critical points by reference surveying on cracked railway bogie frames. And we make an effective load history by synthesizing the dynamic load measured from the critical points of railway bogie frame during commercial line operation and the static load calculated from structural analysis. Crack growth analyses are performed at the 3 critical points under the commercial operation loading condition by assuming an initial crack size as 40 mm. and the results are compared with the experimental results from Japanese railway bogie frame crack growth case. From the analysis results, we find that around 500,000 km operating distance is necessary to bring crack growth from the initial crack to unstable crack. And it takes around 3.8 normal operating years. We conclude that it is enough time to detect the crack between normal maintenance period.

• Journal of Korean Neurosurgical Society
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• v.39 no.2
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• pp.92-95
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• 2006

Objective : Severe vertebral body collapse [vertebra plana] is considered a contraindication to vertebroplasty by most authors. The purpose of this study is to determine the efficacy of vertebroplasty in treating severe compression fracture patients with osteoporosis. Methods : 16 patients underwent 18 vertebroplasties following postural reduction for vertebra plana. The fractures were defined vertebrae that have collapsed to more than 75% of their original height. Imaging and clinical features were analyzed, including involved vertebrae level, vertebral height after postural reduction for 2 days, injected cement volume, clinical outcome and complications. Results : Involved veretebra were located from level T7 to L4. Vertebral body collapse averaged 79% [range $12{\sim}25%$] of the original height. After pillow reduction for 2 days, vertebral body height increased 35% of the original height [range $15{\sim}45%$]. The kyphotic wedge was $12^{\circ}$ before procedure and was decreased $7.0^{\circ}$ after vertebroplasty. The mean injected cement volume was 3.8ml [range $2.0{\sim}4.9ml$]. After the procedure, surgical outcome was excellent in 8 [50%] of 16 patients, good in 7 [42%] and unchanged in one [8%]. The mean pain score [VAS score] prior to vertebroplasty was 8.3 and it changed 3.2 after the procure. Cement leakage to the adjacent disc [5 cases] and paravertebral soft tissues [4 cases] developed but there were no major complications. Conclusion : We propose that vertebra plana due to osteoporosis is not a contraindication to vertebroplasty. Vertebroplasty following postural reduction for severe compression fracture is safe and effective treatment.

• Archives of Plastic Surgery
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• v.34 no.3
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• pp.358-364
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• 2007

Purpose: A life-threatening hemorrhage resulting from a severe facial fracture is rare, but it needs a prompt and aggressive treatment. Especially, a massive oronasal bleeding combined with midfacial fracture which may result from the rupture of the internal maxillary artery. With the recent advances in the radiologic intervention, its use has increased for managing these life threatening case. We reviewed its usefulness with our experiences and literatures. Methods: A retrospective review was performed to determine the usefulness of the transcatheter arterial embolization in patients with panfacial trauma. If the vital signs were unstable, cardiopulmonary resuscitation was performed. Oronasal bleeding was controlled with nasal packing and electrocautery. All injured regions were studied by radiologic study including CT. Even after primary management, if the oronasal bleeding was persistent, radiologic intervention was performed 10 patients were treated with transcatheter arterial embolization and the bleeding focus controlled by embolization with polyvinyl alcohol and gelfoam. Results: After the intervention, the vital signs became stable and there were no complications from embolization in the follow-up for 6 months. Also patients could recover through appropriate operations. Conclusion: Transcatheter arterial embolization for maxillofacial injury has many advantages for both, the doctor and the patient. First, less pain is induced than a compression device or an operation, which is another way to treat oronasal bleeding. Second, it does not need general anesthesia. And through a single procedure not only we can know the accurate bleeding point, but we can also bleeding by embolization.

• Geomechanics and Engineering
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• v.11 no.5
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• pp.657-670
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• 2016

The energy dissipation of coal under dynamic loads is a major issue in geomechanics and arising extensive concerns recently. In this study, dynamic loading tests of coal were conducted using a split Hopkinson pressure bar (SHPB) system, the characteristics of dynamic behavior and energy dissipation of coal were analyzed, and the mechanism of energy dissipation was discussed based on the fracture processes of coal under dynamic loads. Experimental results indicate that the energy dissipation of coal under dynamic loads has a positive linear correlation with both incident energy and dynamic compressive strength, and the correlation coefficients between incident energy, dynamic compressive strength and the energy dissipation rate are 0.74 and 0.98, respectively. Theoretical analysis demonstrates that higher level of stress leads to greater energy released during unstable crack propagation, thus resulting in larger energy dissipation rate of coal under dynamic loads. At last, a semi-empirical energy dissipation model is proposed for describing the positive relationship between dissipated energy and stress.