• Journal of Korean Neurosurgical Society
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• v.65 no.6
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• pp.841-845
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• 2022

Objective : Chiari III malformations are extremely rare hindbrain malformations that are associated with a high early mortality rate, or severe neurologic deficits in the survivors. The treatment is early operative closure and cerebrospinal fluid diversion (CSF) shunting. Methods : We operated on 15 patients by repair and excision between July 2014 till June 2020 and retrospective data collection was done. Only one patient doesn't need ventriculoperitoneal (VP) shunt and the other 14 patients need a VP shunt. We described stepwise dissection and untethering of the cerebellum from the bony edge to regrowth and herniation of cerebellum again into this potential space and simple dural closure or repair with graft was done. Results : We started with VP in eight patients (53%) and the other seven patients (46.7%) started with excision and then six patients need VP shunt later on because four patients developed CSF leak and two patients developed increased high intracranial tension. Only four patients (26.7%) needed a blood transfusion. Conclusion : There are variations in the outcome and not all cases of Chiari malformation III will die and severe developmental delay is not a must. Proper management and repair carry a good prognosis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.68-75
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• 2018

In this study, to solve the problems of the conventional crack repair and injection method, high elasticity latex was used as the material of the storage tube to withstand the high pressure in the center part differently from the general port. When the repair solution was injected into the crack part, The TPS method was developed so that the air existing in the TPS can be discharged. In addition, a new infusion port in which a valve blocking the backflow of the remediation solution was installed at the injection port was developed and the physical characteristics of the port were analyzed. As a result of the evaluation, it was found that the filling rate of the remedial solution was improved compared to the existing ordinary injector method, and the cracks were completely filled in the test conditions. Compressive strength and tensile strength after repair showed about 20% decrease after repair in case of using ordinary injector method, while TPS method showed about 2~7% increase after repair. The results of this study showed that the injection port method using the elastic storage tube increased the injection performance and the quality after repair compared to the conventional injector method. The result of this study is expected to be utilized as the basic data for application and commercialization of the result to the practical structure.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.124-129
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• 1999

Background: Ventricular septal defect(VSD) that causes pulmonary hypertension increase right ventricular workload. Echocardiographic assessment of right ventricular systolic time interval (RVSTI) has been used to predict pulmonary artery pressure in various cardiopulmonary diseases. This study was undertaken in infants with simple VSD to observe the alteration of the right ventricular workload through the changes of RVSTI after repair of VSD. Material and Method: We evaluated heart rate, the ratio of the left atrium/aortic root diameter (LA/Ao), right ventricular pre-ejection period(RVPEP), right ventricular ejection time(RVET), and its ratio(RVPEP/RVET) as a predictor of right ventricular workload in 12 children with simple VSD. These were measured three times at the preoperative period, at the 3 month and between 6 month and 1 year(average 9.5${\pm}$1.8month) after repair of VSD by M-mode & Doppler echocardiograph from the pulmonic valve echogram. Result: Heart rate was decreased significantly after repair(137.1${\pm}$13.7 vs 114.4${\pm}$21.1 and 104.1${\pm}$10.2, p<0.01). LA/Ao ratio was decreased significantly after repair(1.71${\pm}$0.32 vs 1.47${\pm}$0.33 and 1.39${\pm}$0.23, p<0.05). RVPEP/RVET were decreased after repair (0.38${\pm}$0.09 vs 0.32${\pm}$0.08 and 0.29${\pm}$0.09, p<0.01). Heart rate corrected RVPEP/RVET were significantly decreased only after 6 months(0.32${\pm}$0.03 vs 0.30${\pm}$0.05 and 0.28${\pm}$0.06, p<0.05). Conclusion: We found elevated right ventricular workload was progressively decreased until more than 6 months after repair and the RVSTI may serve a useful guide in postoperative care for children with VSD.

• Journal of Chest Surgery
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• v.24 no.11
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• pp.1115-1124
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• 1991

Recently the thoracic injuries have been markedly increasing due to the vast increase of traffic accident, industrial disaster, and incidental accident as well as the frequent use of the murderous weapons including gun or rifle. Because the thoracic injuries could involve the heart, lung, and great vessels, and would influence the lives, prompt diagnosis and adequate treatment are essential. Most of thoracic injuries can be managed with the conservative treatment and simple surgical procedure such as closed thoracostomy, but certain cases require open thoracotomy to preserve lives and to return to their normal environment. The authors have analysed the result of 53 cases of open thoracotomy after thoracic injuries mainly according to the patient`s chart review. The mean age was 33.4 years old and male to female ratio was about 5: l. Injury mechanisms that elicited thoracic trauma indicated for open thoracotomy were penetrating[47%] and non-penetrating[53%] injuries. The Most common type of the thoracic lesion was hemothorax with or without pneumothorax and diaphragm rupture was the second. 58\ulcornero of thoracic injuries were accompanied by abdominal injuries and 47% by bone fractures. 34 patients were operated within 24 hours after injury and their average elapsed time was 13.6 hour. The remained patients were operated after 24 hours and their average elapsed time was 7.8 days. 71 cases of operative procedures containing some overlappings were performed: diaphragm repair[28], bleeding control[12], pulmonary and cardiac repair[4 cases] Postoperative complication rate was 32.1% and operative mortality rate was 9.4%[5/53].

• Journal of architectural history
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• v.22 no.6
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• pp.59-66
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• 2013

This study progressed an investigation on the cause of the efflorescence phenomenon of bricks in Suwon Hwaseong Fortress, which is designated as a UNESCO World Heritage by using diverse scientific analyses. The samples were taken in Hwaseong and analyzed using XRD and SEM-EDS for the material identification of efflorescence. We observed under a polarizing microscope and measured absorption factors for the basic investigation for traditional bricks. As a result of material identification, soluble salt($Na_2SO_4$, $KNO_3$) and insoluble salt($CaCO_3$) were detected. There was no big difference between original bricks and repaired bricks under the polarizing microscope. However, in terms of the water absorption rate, bricks which were used for repair nowadays showed low water absorption rate(1%). In conclusion, soluble salt and insoluble salt appeared due to an effect of an air pollution and joint mortar. Soluble salt was removed in the rainy season, but insoluble salt was not removed. As a result of the efficiency and safety tests for chemicals removing efflorescence, chemical E is likely to be the suitable chemicals for the efflorescence phenomenon of traditional bricks in Suwon Hwaseong Fortress. In the future, consideration whether the use of lime is available or not should be studied through comprehensive researches including repair work, construction work and the environment factor with lime. Also, physical, chemical identifications of repairing bricks will be required.

• Journal of Korean Society for Quality Management
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• v.48 no.1
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• pp.201-214
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• 2020

Purpose: The purpose of this paper is to determine an optimal number of cycle times for the replacement under the circumstance where the system is replaced at the periodic time and the multiple number of working cycles whichever occurs first and the system is minimally repaired between the replacements if it fails. Methods: The system is replaced at periodic time () or cycle time, whichever occurs first, and is repaired minimally when it fails between successive replacements. To determine the optimal number of cycle times, the expected total cost rate is optimized with respect to the number of cycle times, where the expected total cost rate is defined as the ratio of the expected total cost between replacements to the expected time between replacements. Results: In this paper, we conduct a sensitivity analysis to find the following results. First, when the expected number of failures per unit time increases, the optimal number of cycle times decreases. Second, when the periodic time for replacement becomes longer, the optimal number of cycle times decreases. Third, when the expected value for exponential distribution of the cycle time increases, the optimal number of cycle times increases. Conclusion: A mathematical model is suggested to find the optimal number of cycle times and numerical examples are provided through the sensitivity analysis on the model parameters to see the patterns for changes of the optimal number of cycle times.

• Journal of the Korean Society of Safety
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• v.23 no.6
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• pp.62-69
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• 2008

As the concerns of dermal exposure of spray painters to isocyanates in the automobile industry, glove performance was examined like permeation rate and breakthrough time including fatigue test. Methylene chloride was used as the solvent for derivatization of the isocyanates with a 97.5% recovery. Ghost wipe pads were used to wipe the surface of the glove material after chemical penetration through the glove material placed under a disposable test cell. Several solvents were tested, such as thinner(xylene, toluene) and cleaning agent(acetone) by using a standard permeation test cell(AS/NZS standard 2161. part 10.3). Solvents accelerate chemical permeation through the gloves more quickly than pure HDI hardener products. The longest breakthrough times were from Nitrosolve gloves, not detected in 8 hours, compared with others like Latex, Neoprene, TNT and Dermo Plus. Therefore Nitrosolve gloves could be recommended as personal protective equipment in crash repair shops. In addition, revised exposure limit of korean regulation should be suggested for employee to minimize the risk of health symptoms.

• Archives of Plastic Surgery
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• v.48 no.3
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• pp.287-292
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• 2021

Background We report the efficacy of a dual-plane approach using a Dufourmentel skin flap with a purse-string suture of the de-epithelized dermis to manage pseudoaneurysm at the vascular access site for hemodialysis. Methods A retrospective analysis was conducted of 61 patients from 2013 to 2018 with pseudoaneurysms at the arteriovenous fistula or graft who were treated with rhomboid excision, vessel repair with a purse-string suture, and a full-thickness Dufourmentel skin flap. The success rate was defined as the probability of complete wound closure and intact vascular access patency without infection or other complications. Results The success rate was 93.4% at 6 months postoperatively. Complications included newly occurring pseudoaneurysms (n=2), wound dehiscence (n=1) and bleeding (n=1). There were no complications such as stenosis or thrombosis from the procedure. Conclusions A dual-plane approach using a Dufourmentel skin flap with a purse-string suture for vessel repair was shown to be a favorable option for managing stable, small (diameter <2 cm) pseudoaneurysms without infection, rapid expansion, or patency issues of the vascular access.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.113-122
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• 2008

In this paper, we consider a periodic preventive maintenance policy in which each preventive maintenance reduces the hazard rate of amount proportional to the failure intensity, which increases since the system started to operate. And the effect of preventive maintenance at each preventive maintenance epoch is different. The expected cost rate per unit time for the proposed model is obtained. We discuss the optimal number N of the periodic preventive maintenance and the optimal period x, which minimize the expected cost rate per unit time and obtain the optimal preventive maintenance schedule for given cost structures of the model. A numerical example is given for the purpose of illustrating our results when the failure time distribution is Weibull distribution.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2008.03a
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• pp.123-124
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• 2008