• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.2
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• pp.134-141
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• 1998

Mutational falsetto is a kind of voice disorders due to the failure to acquire proper low-pitched voice during the puberty. The patients with mutational falsetto can produce the normal low-pitched voice by the surgical treatment, like the type III-thyroplasty, or the voice therapy. The present study is, focusing on the latter treatment, to consider the efficiency of voice therapy for the mutational falsetto. The 7 patients who were diagnosed as mutational falsetto by the laryngologists, and treated by the voice therapist were selected as subjects. Their voices of pretherapy and posttherapy were analyzed on the aspects of acoustics and aerodynamics. Acoustic analysis was done by the MDVP(Multidimensional Voice Program) of CSL(Computerized Speech Lab, Kay Elemetrics, Co.), and aerodynamic analysis, by the Maximum Sustained Phonation of Aerophone II(Kay Elemetrics, Co.). By these measurements, we could find that fundamental frequency(F0) was significantly lowered, on the average, 65Hz. Maximum phonation time(MPT) was increased 4.57 second, and shimmer was decreased 1.644%, respectively, and each changes was statistically significant, too. On the average, jitter was decreased 0.499%, mean flow rate(MFR) was decreased 27.71ml/sec, and NHR was increased 0.023 which was the only parameter not showing improvement. But the changes of jitter, MFR and NHR were not statistically significant.

• Journal of Chest Surgery
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• v.33 no.10
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• pp.792-797
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• 2000

Background : Even though there were developments in various treatment techniques for acute arterial occlusion this disease still has high rate of mortalities and limb amputations. We investigated the combined diseases symptoms location of occlusion type of treatment complication and prognosis in our patients. Meterial and methods: This study recruited 48 patients(42 men, 6 women, mean age 57.7 years) who received the operation from January 1995 toDecember 1998. We investigated the post-operation course via medical record review or telephone interview with patients or their family members. Result: The most common combined diseases were atherosclerosis in 30 patients. other diseases were 17 diabetes mellitus 16 hypertension and 12 atrial firillation. Pain and clod sensation were noticed in all patients paresthesia in 5 patients fibrillation. Pain and cold sensation were noticed in all patients paresthesia in 5 patients and lower extremity paralysis in 11 patients. In 29 patients the time interval from the onset of symptom to admission was over 72 hours and 15 patients were admitted within 24 hours. The distribution of arterial occlusion location was at 28 femoral arteries 14 popliteal arteries and 6 iliac arteries. All the patients were received embolectomy and 5 patients were received additional bypass grafting. Postoperative complications were 12 reocclusions. 6 compartment syndromes 6 skin necrosis and 2 acute renal failure. The mortality rate was 16.7%(8/48) and the amputation rate was 25% Conclusion : This study revealed 25% reocclusion 25% limb amputation and 16.7% mortaliyt. To improve the prognosis of acute lower extrements arterial occlusion early diagnosis and understand the underlying diseases prompt treatment and operation additional operation including interventional radiologic examination and thorough postoperative care would be appreciated.

• Journal of Chest Surgery
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• v.19 no.3
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• pp.363-373
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• 1986

Even though the pathogenesis is still controversial, electrocardiographic changes after congenital open heart surgery depend on various etiologic factors. Author reviewed 261 cases of congenital open heart surgery patient experienced in the Dept. of Thoracic & Cardiovascular Surgery, Pusan National University Hospital, since July, 1981 to Sept., 1985. The results were summarized as followed: 1. The age distribution was from 3 to 29 years old with mean age 10.8 years. And the most frequent congenital heart defect we had done operation was VSD. 2. Preoperatively, the most frequent ECG finding was abnormal QRS complex and postoperatively the most frequent ECG change was arrhythmia. 3. The most frequent arrhythmia before operation was intraventricular conduction disturbance. 4. Right ventriculotomy incision produced the more frequent abnormal ECG changes postoperatively than right atriotomy or pulmonary arteriotomy. 5. According to the operative technique, outflow patch graft of TOF repair produced the highest frequency of ECG changes after operation, and in comparing simple and patch closure of VSD, the latter was higher frequency of ECG changes, in valvotomy and infundibulectomy of PS, the latter was higher too. 6. The common symptom and signs in abnormally ECG changed patients after operation were palpitation, dyspnea, congestive heart failure and murmur in this order., 7. The longer the time of CPB, the more number of abnormally ECG changed patients had been developed after operation. 8. The most of postoperative ECG changed patients recovered spontaneously or with only medication and were clinically insignificant. And the rest other minor group recovered with temporary pacing. Eight cases out of 261 [3.1%], these with abnormal QRS complex and arrhythmia couldn`t recover in spite of every effort and eventually succumbed.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.91-95
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• 2007

Electromigration characteristics of Sn-3.5Ag flip chip solder bump were analyzed using flip chip packages which consisted of Si chip substrate and electroplated Cu under bump metallurgy. Electromigration test temperatures and current densities peformed were $140{\sim}175^{\circ}C\;and\;6{\sim}9{\times}10^4A/cm^2$ respectively. Mean time to failure of solder bump decreased as the temperature and current density increased. The activation energy and current density exponent were found to be 1.63 eV and 4.6, respectively. The activation energy and current density exponent have very high value because of high Joule heating. Evolution of Cu-Sn intermetallic compound was also investigated with respect to current density conditions.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.459-469
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• 2019

It is important to estimate the shear strength of shallow compacted soils as a construction material. A series of constant water content triaxial compression (CWCC) tests under low confining state in this study were performed on compacted geomaterials. For establishing a relationship of the shear strengths between saturated and unsaturated states on compacted geomaterials, the suction stresses were derived by two methods: the conventional suction-measured method and the Suction stress-SWRC Method (SSM). Considering the suction stress as an equivalent confining stress component in the (${\sigma}_{net}$, ${\tau}$) plane, it was found that the peak deviator stress states agree well with the failure line of the saturated state from the triaxial compression test when the SSM is applied to obtain the suction stress. On the other hand, the cavitation phenomenon on the measurement of suction affected the results of the conventional suction-measured method. These results mean that the SSM is distinctly favorable for obtaining the suction value in the CWCC test because the SSM is not restricted by the cavitation phenomenon. It is expected that the application of the SSM would reduce the time required, and the projected cost with the additional equipment such as a pore water measuring device in the CWCC test.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.254-259
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• 2019

Objectives: Crown-root fracture and cervical caries in maxillary premolars constitute a challenge in cases of subgingival placement of restoration margins. Surgical extrusion has been practiced successfully in permanent anterior teeth. The aim of the present retrospective study was to assess the clinical outcome of surgical extrusion after orthodontic extrusion in maxillary premolars. Materials and Methods: Twenty-one single, tapered root maxillary premolars with subgingival crown-root fracture or caries were included. Presurgical orthodontic extrusion was performed on all teeth to prevent root resorption. Extent of extrusion and rotation was determined based on crown/root ratio. The postoperative splinting period was 7 to 14 days. Clinical and radiographic examination was performed at an interval of 1, 2, and 3 months. Results: After the mean follow-up of $41.9{\pm}15.2months$, failure was observed as increased mobility in 3 of 21 cases. No significant difference was observed in the outcome of surgical extrusion based on tooth type, age, sex, $180^{\circ}$ rotation, or time for extraction. Furthermore, marginal bone loss was not observed. Conclusion: Surgical extrusion of maxillary premolars can be a possible therapeutic option in cases of subgingival crown-root fracture.

• Clinical Endoscopy
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• v.55 no.1
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• pp.128-135
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• 2022

Background/Aims: Recent reports suggest that the biliary self-expandable metallic stent (SEMS) is highly effective for maintaining hemostasis when endoscopic hemostasis fails in endoscopic retrograde cholangiopancreatography (ERCP)-related bleeding. We compared whether temporary SEMS offers better efficacy than angioembolization for refractory immediate ERCP-related bleeding. Methods: Patients who underwent SEMS placement or underwent angioembolization for bleeding control in refractory immediate ERCP-related bleeding were included in the retrospective analysis. We evaluated the hemostasis success rate, severity of bleeding, change in hemoglobin levels, amount of transfusion, and delay to the start of hemostasis. Results: A total of 27 patients with SEMS and 13 patients who underwent angioembolization were enrolled. More transfusions were needed in the angioembolization group (1.0±1.4 units vs. 2.5±2.0 units; p=0.034). SEMS failure was successfully rescued by angioembolization. The partially covered SEMS (n=23, 85.1%) was generally used, and the median stent-indwelling time was 4 days. The mean delay to the start of angioembolization was 95.2±142.9 (range, 9-491) min. Conclusions: Temporary SEMS had similar results to those of angioembolization (96.3% vs. 92.3%; p=0.588). Immediate SEMS insertion is considered a bridge treatment modality for immediate refractory ERCP-related bleeding. Angioembolization still has a role as rescue therapy when SEMS does not work effectively.

• Journal of Korean Neurosurgical Society
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• v.65 no.1
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• pp.123-129
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• 2022

Objective : Chronic subdural hematoma (CSDH) is one of the most common pathology in daily neurosurgical practice and incidence increases with age. The aim of this study was to evaluate the prognostic factors and surgical outcome of CSDH in patients aging over 90 years compared with a control group of patients aging under 90 years. Methods : This study reviewed 25 patients with CSDH aged over 90 years of age treated in our department. This group was compared with a younger group of 25 patients aged below their eighties. At admission past medical history was recorded concerning comorbidities (hypertension, dementia, ictus cerebri, diabetes, and heart failure or attack). History of alcohol abuse, anticoagulant and antiplatelet therapy, head trauma and seizures were analyzed. Standard neurological examination and Markwalder score at admission, 48 hours after surgery and 1-6 months follow-up, radiologic data including location and CSDH maximum thickness were also evaluated. Results : Their mean age was 92.8 years and the median was 92.4 years (range, 90-100 years). In older group, the Markwalder evaluation at one month documented the complete recovery of 24 patients out of 25 without statistical difference with the younger group. This data was confirmed at 6-month follow-up. One patient died from cardiovascular failure 20 days after surgery. The presence of comorbidities, risk factors (antiplatelet therapy, anticoagulant therapy, history of alcohol abuse, and head trauma), preoperative symptoms, mono or bilateral CSDH, maximum thickness of hematoma, surgical time and recurrence were similar and statistically not significant in both groups. Conclusion : In this study, we demonstrate that surgery for very old patients above 90 years of age affected by CSDH is safe and allows complete recovery. Comparing two groups of patients above and under 90 years old we found that complication rate and recovery were similar in both groups.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.7
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• pp.569-575
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• 2008

In this study, disk type of thermal barrier coating system for gas turbine blade was isothermally aged in the furnace changing exposure time and temperature. For each aging condition, bond tests for three samples were conducted for evaluating degradation of adhesive or cohesive strength of thermal barrier coating system. For as-sprayed condition, the location of fracture in the bond test was in the middle of epoxy which have bond strength of 57 MPa. As specimens are degraded by thermal aging, bond strength gradually decreased and the location of failure was also changed from within top coat at the earlier stage of thermal aging to the interface between top coat and TGO at the later stage due to the delamination in the coating.

• Tuberculosis and Respiratory Diseases
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• v.61 no.1
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• pp.26-33
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• 2006

Background: Noninvasive positive pressure ventilation(NPPV) has been increasingly used over the past decade in the management of acute or chronic respiratory failure and weaning of mechanical ventilation. We performed this clinical study to evaluate the usefulness of NPPV in patients who developed acute respiratory failure or post-extubation respiratory failure. Methods: We analysed thirty four patients(sixteen males and eighteen females, mean ages 58 years) who applied NPPV(BIPAP S/T, Respironics co., USA) for respiratory failure or weaning difficulty at medical intensive care unit(MICU), emergency room and general ward of a tertiary hospital. We evaluated the underlying causes of respiratory failure, duration of treatment, the degree of adaptation, complication and predictive parameters of successful outcome. Results: The overall success rate of NPPV was seventy-one percent. The duration of NPPV applying time, baseline blood pressure, pulse rate, respiration rate, $PaO_2$, $PaCO_2$, $SaO_2$ were not different between success group and failure group. But, the baseline pH was higher in the success group. Predictors of success were higher baseline pH, patients with underlying disease of COPD, improvement of vital sign and arterial blood gas value after NPPV application. The success rate in patients with post-extubation respiratory failure was eighty percent. There were no serious complication on applying NPPV except minor complications such as facial skin erythema, abdominal distension & dry mouth. Conclusion: NPPV may be effective treatment in patients with acute respiratory failure or post-extubation respiratory failure in selected cases.