• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.363-382
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• 2015

This paper presents a numerical study on the effect of segment assembly characteristics on the TBM segmental lining member section forces. Analyses have been carried out through the two-ring beam finite element model by Midas civil 2012+. TBM segment lining member forces are determined by various joint characteristics. In this study, the segmental member forces were investigated with various joint number and orientation at fixed values of joint stiffness, ground spring parameters. The numerical results were used to identify trends of the member forces in the tunnel lining with the segment assembly characteristics.

• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.741-750
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• 2018

The aim of this study was to investigate the mechanical responses of a high-speed railway shield tunnel subjected to impact by a derailed train, with emphasis on the protective effect of the secondary lining. To do so, the extended finite element method was used to develop two numerical models of a shield tunnel including joints and joint bolts, one with a cast-in-situ concrete secondary lining and one without such a lining. The dynamic responses of these models upon impact were analyzed, with particular focus on the distribution and propagation of cracks in the lining structures and the mechanical responses of the joint bolts. The numerical results showed that placing a secondary lining significantly constricted the development of cracking in the segmental lining upon the impact load caused by a derailed train, reduced the internal forces on the joint bolts, and enhanced the safety of the segmental lining structure. The outcomes of this study can provide a numerical reference for optimizing the design of shield tunnels under accidental impact loading conditions.

• Journal of Korean Neurosurgical Society
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• v.45 no.3
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• pp.192-195
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• 2009

We present a case of an acute psoas muscle hematoma following percutaneous endoscopic lumbar discectomy. A 60-year-old female who presented with far lateral lumbar disc herniation underwent endoscopic discectomy on the right side at the L4-5 level. On the second postoperative day, the patient complained of severe right flank and leg pain and her blood pressure decreased. A computed tomography scan showed a large acute psoas muscle hematoma at right L4-5 level. The patient was transfused with packed red blood cells and placed at absolute bed rest. After observing the patient in intensive care, the severe flank and leg pain subsided, but the mild back pain persisted. Although percutaneous endoscopic lumbar discectomy is an effective minimally invasive surgical technique for the treatment of lumbar disc herniation, this case highlights the inherent risks of acute lumbar segmental vessel injury.

• Korean Journal of Veterinary Research
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• v.57 no.2
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• pp.113-116
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• 2017

The aim of this study was to examine normal bronchi in dogs by using virtual bronchoscopy (VB) and to evaluate the utility of VB in clinical practice. The bronchi of six dogs without tracheobronchial disease were visualized by VB. Airways from the tracheal bifurcation to the lobar bronchi were well visualized in all dogs. Segmental and subsegmental bronchi were also well identified, but the degree and number of those varied with dog size. The mean numbers of segmental and subsegmental bronchi identified in the six dogs were 41.83 and 50.17, respectively, whereas, the mean numbers in medium- and large-sized dogs were 55.00 and 82.67, respectively, and in small-sized dogs, the means were 28.67 and 17.67, respectively. Although there were size-dependent differences in VB visualization of the bronchi, it was possible to identify peripheral airways to the subsegmental bronchi level, which can rarely be accomplished via conventional bronchoscopy. VB is the noninvasive method that can be used to examine bronchial anatomy, and our results suggest that VB can be useful for evaluating bronchi, including segmental and subsegmental ones that cannot be examined routinely by conventional bronchoscopy. Thus, VB has potential as an alternative to conventional bronchoscopy in the examination of bronchi in dogs.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.115-125
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• 2003

This paper presents the results of design case study on soil-reinforced segmental retaining walls in tiered configuration. Six different field walls were examined to investigate the appropriateness of their designs within the context of the current design guidelines based on limit equilibrium. Slope stability analysis against the compound failure mode, which is frequently ignored during design, was additionally performed based on the method recommended by FHWA design guidelines. The results indicate that the as-built designs of some of the walls examined do not meet the minimum factors of safety for the external and Internal stabilities, and for the compound failure mode. The implications of the findings from this study are discussed.

• Journal of Chest Surgery
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• v.48 no.4
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• pp.285-288
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• 2015

In coronary artery bypass grafting, a diffusely diseased left anterior descending coronary artery (LAD) is an obstacle to achieving complete revascularization, consequently leading to the possibility of a poor prognosis. Long segmental reconstruction with or without endarterectomy is a revascularization method for treating diffusely diseased coronary arteries. Herein, we report a successful case of long segmental reconstruction of a diffusely diseased LAD using a left internal thoracic artery onlay patch after endarterectomy.

• Geomechanics and Engineering
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• v.23 no.4
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• pp.351-364
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• 2020

This paper numerically investigates the effects of a dip-slip fault (a normal or a reverse fault) movement on a segmental tunnel which transversely crosses either of this kind of faults. After calibration of the numerical model with results from literature of centrifuge physical tests, a parametric study is conducted to evaluate the effects of various parameters such as the granular soil properties, the fault dip angle, the segments thickness, and their connections stiffnesses on the tunnel performance. The results are presented and discussed in terms of the ground surface and tunnel displacements along the longitudinal axis for each case of faulting. The gradient of displacements and deformations of the tunnel cross section are also analyzed. It is shown that when the fault dip angle becomes greater, the tunnel and ground surface displacements are smaller, in the case of reverse faulting. For this type of fault offset, increasing the tunnel buried depth causes tunnel displacements as well as ground surface settlements to enhance which should be considered in the design.

• Clinical and Experimental Pediatrics
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• v.59 no.5
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• pp.242-245
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• 2016

Thromboembolic complications (TECs) are clinically important sequelae of nephrotic syndrome (NS). The incidence of TECs in children is approximately 2%-5%. The veins are the most commonly affected sites, particularly the deep veins in the legs, the inferior vena cava, the superior vena cava, and the renal veins. Arterial thrombosis, which is less common, typically occurs in the cerebral, pulmonary, and femoral arteries, and is associated with the use of steroids and diuretics. Popliteal artery thrombosis in children has been described in cases of traumatic dissection, osteochondroma, Mycoplasma pneumoniae infection, and fibromuscular dysplasia. We report of a 33-month-old girl with bilateral iliac and popliteal arterial thrombosis associated with steroid-resistant NS due to focal segmental glomerulosclerosis. Her treatment involved thrombectomy and intravenous heparinization, followed by oral warfarin for 8 months. Herein, we report a rare case of spontaneous iliac and popliteal arterial thrombosis in a young child with NS.

• The korean journal of orthodontics
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• v.50 no.4
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• pp.278-289
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• 2020

Orthodontic treatment of posterior bite collapse due to early loss of molars and the consequent drift of adjacent teeth is complicated. When the posterior bite collapse occurs in patients with facial asymmetry, both transverse and vertical compensation are necessary for camouflage orthodontic treatment. In such cases, posterior maxillary segmental osteotomy (PMSO) can be an effective alternative procedure that simplifies the orthodontic treatment and shows long-term stability through dental compensation within the alveolar bone housing. This case report aimed to describe the orthodontic treatment of maxillary occlusal plane canting caused by severely extruded maxillary teeth in a patient with skeletal facial asymmetry that was corrected with PMSO along with protraction of the lower second molar to replace the space of the extracted first molar. The treatment duration was 18 months, and stable results were obtained after 2 years of retention.

• Archives of Plastic Surgery
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• v.41 no.5
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• pp.584-587
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• 2014

In the present study, a fibular osteotomy guide based on a computer simulation was applied to a patient who had undergone mandibular segmental ostectomy due to oncological complications. This patient was a 68-year-old woman who presented to our department with a biopsy-proven squamous cell carcinoma on her left gingival area. This lesion had destroyed the cortical bony structure, and the patient showed attenuation of her soft tissue along the inferior alveolar nerve, indicating perineural spread of the tumor. Prior to surgery, a three-dimensional computed tomography scan of the facial and fibular bones was performed. We then created a virtual computer simulation of the mandibular segmental defect through which we segmented the fibular to reconstruct the proper angulation in the original mandible. Approximately 2-cm segments were created on the basis of this simulation and applied to the virtually simulated mandibular segmental defect. Thus, we obtained a virtual model of the ideal mandibular reconstruction for this patient with a fibular free flap. We could then use this computer simulation for the subsequent surgery and minimize the bony gaps between the multiple fibular bony segments.