• Journal of Periodontal and Implant Science
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• v.38 no.4
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• pp.611-620
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• 2008

Purpose: The purpose of this study was to assess the long term survival rates of the most posterior single tooth implant and to evaluate the influence of implant characteristics on implant survival. Material and Methods: This retrospective report presents findings on 37 patients with 43 implants replacing single molars. The inclusion criteria were having implants replacing a molar of the most posterior region and follow-up data over at least 6 months. Data were recorded regarding the incidence of complications and survival rates of these implants. Results: The range of follow-up was from 9 to 66 months(mean: 40.2 months). The cumulative survival rate of total implants was 93.0% which reflects the loss of three implants: one had broken neck, one implant failed because of infection, one implant showed failed osseointegration. Abutment- screws loosening occurred in five implants(11.6%). Conclusion: Within the limits of this study, a single tooth-implant can serve as a good long-term and predictable treatment modality to replace the most posterior teeth with low complication and failure rates.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.30 no.2
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• pp.77-81
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• 2019

Dysphagia may result from dysfunction of any of the components involved in the complex neuromuscular interaction of swallowing. Hyperfunction of any of the muscles involved in swallowing is a frequent cause of dysphagia. The cricopharyngeus muscle (CPM) is a key component of the upper esophageal sphincter. Cricopharyngeus muscle dysfunction (CPD) refers to the muscle's failure to appropriately and completely relax or expand during deglutition. A variety of disease processes may cause CPD and accurate diagnosis is paramount for appropriate treatment. In appropriately selected patients, intervention at the CPM may yield significant improvement in dysphagia. Interventions include nonsurgical, pharyngoesophageal segment dilatation, botulinum toxin (BoNT) injection, and criccopharyngeal myotomy. Injections of BoNT in patients with CPD have been reported to result in marked relief of dysphagia. Different techniques for instilling BoNT into the CPM have been described. Awake, in-office CPM BoNT injection with electromyography and/or fluoroscopic or ultrasound guidance is performed transcervically or via flexible endoscopy. Operative CPM BoNT injection involves rigid laryngoscopy and esophagoscopy with direct visualization of the CPM. BoNT should be prepared in low-volume, high-concentration dilutions to minimize the potential for undesired diffusion of the toxin. The effects of BoNT occur within weeks of injection and typically last up to 5 or 6 months.

• Archives of Reconstructive Microsurgery
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• v.9 no.1
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• pp.49-55
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• 2000

Nonunion and avascular necrosis are well-recognized complications of severe ankle injury especially aftrer talar neck fracture. The treatment of avascular necrosis is controversial and methods of treatment are limited. Many modalities have been introduced for the treatment of avascular necrosis of talus. The prolonged non-weight bearing for 2~3 years is not practical but also is occasionally complicated by late segmental collapse. Operative treatment includes tibiotalar arthrodesis and talectomy with tibiocalcaneal arthrodesis, but arthrodesis in patients with talar avascular necrosis is technically demanding and cause stiff, immobile foot and relatively high failure rate was reported. It is desirable to preserve their original joint if possible. Vascularized fibular grafting has been reported as a joint preserving treatment option for osteonecrosis of the hip but has not been described for the ankle. The authors applied free vascularized fibular grafts for 3 cases of avascular necrosis of talus. We observed evidences of revascularization of necrotic talar body and progression of fracture healing and obtained satisfactory results at mean 8 months of follow-up. Vascularized fibular grafting is one of the better alternatives for treating avascular necrosis of talus. It is expected that vascularized fibular grafting can prevent the necrotic talar dome from progressing to collapse and promote directly restored vascularization and new bone formation.

• Journal of Chest Surgery
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• v.22 no.1
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• pp.67-73
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• 1989

Forty two patients with chronic constrictive pericarditis, who were admitted to the Yonsei University College of medicine over a period of 18 years from January, 1970 to August, 1988, were analyzed retrospectively. Mean age of the patient was 33.5 year ranging from 6.8 to 60 years old. Male to female ratio was 1.3 to 1. Twenty-one cases [50%] were tuberculous origin [based on either associated pulmonary tuberculosis and/or caseous necrosis in thickened pericardial specimen] and 17 cases [40.5%] were idiopathic [non specific chronic inflammatory change was considered to be idiopathic]. Dyspnea on exertion was evident in 30 cases [71.4%] and abdominal distention in 21 cases [50%]. On physical examination, hepatomegaly [83.3%], neck vein distention [54.8%], distant heart sound [47.6%] and ascites were found. Thirty-nine patients showed low voltage of QRS and/or T wave flattening or inversion on EKG. Thirty-one cases had undergone cardiac catheterization which showed data compatible with chronic constrictive pericarditis. Midsternostomy group [n=15] had shown the most remarkable CVP decline [12.20 mmHg] as compared with bilateral submammary incision group [n=25, 8.96 mmHg] and left thoracotomy group [n=2, 7.75 mmHg] but difference was not significant statistically There was four early death among 42 patients [9.5%] including 3 cases of left ventricular failure and one cardiac tamponade. Main postoperative complications were wound infection [6 cases] and arrhythmia [3 cases]. Follow-up of 24 patients [mean; 55.3 months, ranging from 2 months to 155 months] revealed good functional status.

• Transactions of Materials Processing
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• v.21 no.5
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• pp.285-290
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• 2012

In spite of progress in predicting ductile failure, the development of a macroscopic yield criterion to describe damage evolution in HCP (hexagonal close-packed) materials remains a challenge. HCP materials display strength differential effects (i.e., different behavior in tension versus compression) in their plastic response due to twinning. Cazacu and Stewart(2009) developed an analytical yield criterion for porous material containing randomly distributed spherical voids in an isotropic, incompressible matrix that shows tension-compression asymmetry. The goal of the calculations in this paper is to investigate the effect of the tension-compression asymmetry on necking induced by void nucleation, evolution and consolidation. In order to investigate the effect of the tension-compression asymmetry of the matrix on necking and fracture initiation, three isotropic materials A, B, and C were examined with different ratios of tension-compression asymmetry. The various types of material had BCC, FCC, and HCP crystal structures, respectively. The ratio between tension and compression in plastic flow significantly influences the fracture shape produced by damage propagation as well as affecting the localized neck.

• Journal of Chest Surgery
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• v.24 no.1
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• pp.98-105
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• 1991

There have been reports concerning the association of laryngeal carcinoma and lung cancer. Second primary respiratory tract malignancies occur frequently in patients who have undergone the treatment of laryngeal cancer probably because they are exposed to the same carcinogen. Recently, we have experienced two patients who developed second primary lung cancer 30 and 41 months after the first diagnosis of laryngeal cancer at the Department of Thoracic & Cardiovascular Surgery, Yonsei University College of Medicine. Relative long interval between the two carcinomas indicated metastasis unlikely. From a therapeutic standpoint, it is of great importance that they should be regarded as separate primaries and not as metastasis. Longevity will depends on a presumption that the lesions are separate primaries and the status of stage at the time of detection of second primary lesion. The follow-up of patients who are seen with carcinomas of the head and neck should be done at regular interval and include a chest roentgenogram and cytologic examination of sputum to detect early changes before the tumors becomes incurable. The first 76 year old patient with left upper lobectomy due to the T2N0M0 lung cancer has been in good condition to present. But the second 55 year old patient with right pneumonectomy due to the T2N0M0 lung cancer died of respiratory failure and septic pneumonia 3 months after operation and chemotherapy.

• Journal of Korean Neurosurgical Society
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• v.52 no.1
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• pp.21-26
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• 2012

Objective : To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. Methods : We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. Results : Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. Conclusion : Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.

• Journal of Korea Foundry Society
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• v.24 no.6
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• pp.323-330
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• 2004

This study aims to investigate on the effects of the microstructures on the wear characteristics of the different grey cast iron(GC) and spheroidal ductile cast iron(DCI). Wear test using wear tester of pin-on-disc type was carried out under the conditions of load 47.2N , velocity 0.2m/s, distance 4000m. At the GC, Wear rates depend on graphite type and oxide layer formed at wear surface. Weak rosette graphites are easily broken and formed wear debris over 30 ${\mu}m$. This wear debris occurs scuffing at wear surface. As a result of surface deformation, Narrow regions of the matrix between the graphite flakes and the contact surface lead to the failure of the necks. Wear rate for the DCI depended on hardness of matrix more than size of graphite.

• Journal of The Korean Dental Society of Anesthesiology
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• v.13 no.3
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• pp.127-131
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• 2013

We experienced failed airway management in a patient who had partial mandibulectomy and reconstruction with free-flap. 40 year-old man (height: 164 cm, body weight: 59 kg) with malignant melanoma on #38 tooth area of mandibular body was scheduled for partial mandibulectomy and reconstruction with free flap. Approximately fifteen-hours after surgery, the patient was extubated without complication. Seven hours after extubation, we experienced respiratory failure andfailed airway managementdue to airway edema and neck. We failed orotracheal intubation with direct laryngoscopy andlaryngeal mask airway, thus we tried tracheostomy but the patient was hypoxic state for more than 30 minutes. The patient had got hypoxic brain damage in whole cerebral cortex and basal ganglia. We should have the policy of airway management of the patients who have massive oro-maxillo-facial surgery and all medical personnel who treat these patients should be educated the policy and airway management methods.

• Structural Engineering and Mechanics
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• v.36 no.4
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• pp.481-497
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• 2010

The shaking table tests were conducted on two small-scale models (Model 1 and Model 2) to examine the earthquake-induced damage of a concrete gravity dam, which has been planned for the construction with the recommendation of the peak ground acceleration of the maximum credible earthquake of 0.42 g. This study deals with the numerical simulation of shaking table tests for two smallscale dam models. The plastic damage constitutive model is used to simulate the crack/damage behavior of the bentonite-concrete mixture material. The numerical results of the maximum failure acceleration and the crack/damage propagation are compared with experimental results. Numerical results of Model 1 showed similar crack/damage propagation pattern with experimental results, while for Model 2 the similar pattern was obtained by considering the modulus of elasticity of the first and second natural frequencies. The crack/damage initiated at the changing point in the downstream side and then propagated toward the upstream side. Crack/damage accumulation occurred in the neck area at acceleration amplitudes of around 0.55 g~0.60 g and 0.65 g~0.675 g for Model 1 and Model 2, respectively.