• Journal of Chest Surgery
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• v.44 no.2
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• pp.137-141
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• 2011

Background: There is controversy about the benefit of surgical correction of an atrial septal defect (ASD) in patients over 60 years old. The purpose of this study was to determine whether surgical treatment is beneficial in those 60 years of age or older. Materials and Methods: We reviewed the clinical course of 57 patients (mean age: $63.54{\pm}5.59$ years) diagnosed with an isolated secundum ASD after the age of 60. The 24 patients (group A) who underwent surgical repair were compared with the 33 patients (group B) who were treated non-surgically. The mean follow-up period was $6.8{\pm}4.5$ years. Results: One operative death, 5 late deaths (20.8%) in group A, and 9 deaths (27.3%) in group B occurred in the study period. Symptomatic improvement was noted in 18 patients (75%) of group A after surgery. However 13 patients (39.4%) of group B showed symptomatic improvement during the follow-up period (p=0.012). The incidence of new atrial arrhythmia of the two groups was significantly different (16.7% vs 36.7%, p=0.038). The actuarial 10 year survival rate was 79% in group A and 73% in group B. Conclusion: Although surgical correction of ASD did not increase survival in patients over 60 years old, the surgical outcomes of ASD showed low operative mortality and resulted in symptomatic improvement in the majority of these patients. This study has shown the benefits of surgical closure of ASD even in advanced age in comparison to medical treatment.

• Journal of Life Science
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• v.17 no.2 s.82
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• pp.230-234
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• 2007

Oxygen is required for many important aerobic cellular reactions, it may undergo electrontransfer reactions, which generate highly reactive membrane-toxic intermediates (reactive oxygen species, ROS), such as hydrogen peroxide, singlet oxygen, superoxide radical, hydroxyl radical, hydroperoxyl radical, hydroxy ion. Various mechanisms are available to protect cells against damage caused by oxidative free radicals, including scavenging enzyme systems such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). This antioxidant defense system is a very complex and finely tuned system consisting of enzymes capable of detoxifying oxygen radicals as well as low molecular weight antioxidants. In addition, repair and turnover processes help to minimize subcellular damage resulting from free radical attack. $H_2O_2$,one of the major ROS, is produced at a high rate as a product of normal aerobic metabolism. The primary cellular enzymatic defense systems against $H_2O_2$ are the glutathione redox cycle and catalase. From Northern blot analysis of total RNAs from cultured cell with $H_2O_2$ treatment, various results were obtained. Expression of Cu/Zn SOD decreased when cell passage increased, but the level of the Cu/Zn SOD was scarcely expressed in 35 passage.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.3
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• pp.151-156
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• 2003

This study was performed to develop a useful nerve conduit which provides favorable environment for Schwann cell viability and proliferation. Milipore membrane of $0.45{\mu}m$ pore size was selected because it permits nutritional inflow from the outside of the conduit and prevents from invading the fibrotic tissue into the conduit. The membrane was rolled and sealed to form a conduit of 2mm diameter and 20mm length. To improve the axonal regeneration and to render better environment for endogenous and exogenous Schwann cell behaviour, the microgeometry and surface of conduit was modified by coating with thin film of calcium phosphate. Cellular viability within the conduit and attachment to its wall were assessed with MTT assay and SEM study. Milipore filter conduit showed significantly higher rate of Schwann cell attachment and viability than the culture dish. However, the reverse was true in case of fibroblast. Coating with thin film of low crystalline calcium phosphate made more favorable environment for both cells with minimal change of pore size. These findings means the porous calcium phosphate coated milipore nerve conduit can provide much favorable environment for endogenous Schwann cell proliferation and exogenous ones, which are filled within the conduit for the more advanced strategy of peripheral nerve regeneration, with potential of reducing fibrotic tissue production.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.527-537
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• 2007

To evaluate criteria, indications, and prognosis of the various reconstructive methods on the patients with intraoral soft tissue defect who had been treated at Dept. of Oral and Maxillofacial Surgery, Pusan National University Hospital from 2003 to 2005, we have reviewed the clinical data of the patients and analysed. The results were as follows: 1. Tongue flaps have been mainly applied on anterior portion of palate and maxilla. The survival rate was high percent, but the cooperation of patient was inevitable for the success. 2. Palatal mucosa rotational flaps were available on relative large defect on palate, oroantral fistula site. The side effect was a scaring band from secondary healing on denuded donor palate site. Sometimes the band came to be a hinderance to swallowing, phonation. 3. Forearm free flap was a workhorse flap for everywhere in intraoral defects. We had used the flap on cheek, floor of mouth, tongue without any significant complications. But the application of the flap was required for long operation time, which was disadvantageous to the old, weak patients. 4. Cervical platysmal flap could be easily applicable for buccal cheek, floor of mouth after excision of the cancer lesion. The design of the flap could be made simultaneously on neck dissection, but the danger of cancer remnants on the flap always might be remained. 5. Buccal fat pad pedicled flap must have been a primary flap for repair of oroantral fistula especially on posterior maxilla. The flap survival will be expected if the considerations for above reconstructive methods on site, size, condition of defects primarily could be made.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.1
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• pp.13-25
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• 2009

Purpose: The DNA repair protein, $O^6$-methylguanine-DNA methyltransferase (MGMT), removes alkyl adducts from the $O^6$ position of guanine. Epigenetic inactivation of MGMT has been found in human neoplasia and considered one of the implicated factors in chemoresistance. Materials and Methods: Sixty-two patiensts with soft tissue sarcomas (STS) were analyzed for the status of MGMT protein expression by immunohistochemistry and the promoter hypermethylation of the MGMT gene using methylation-specific PCR. Result: The loss of MGMT expression was found in 20 cases (32.3%) of total 62 STS. MGMT promoter hypermethylation rate was 25.0% (11/44 cases). The loss of MGMT expression showed significant association with high AJCC stage, high FNCLCC grade, and aggressive behavior. However,when the group who received chemotherapy was analyzed (n=27), loss of MGMT expression was correlated with worse survival in multivariate analysis (p=0.024). MGMT promoter hypermethylation is associated with high FNCLCC grade. MGMT promoter hypermethylation status had a strong correlation with loss of MGMT expression (p=0.000). Conclusion: Our results suggest that MGMT promoter hypermethylation and loss of MGMT expression had a tendency to be associated with poor prognosis and that loss of MGMT protein expression is frequently occurs via MGMT promoter hypermethylation.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.489-498
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• 2005

Recently, the deterioration of concrete structures have been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the deterioration of concretes have been taken. Among them, it has been often used that surface treatment which cut off the deterioration factors of durability by protecting the surface of concrete. The water proof and repair materials for concrete mainly use organic materials such as epoxy, these materials excel in intial bonding force and resistance to chemical agents. But they cause difference in the modulus of elasticity and the rate of shrinkage and expansion of concrete, and thus result in such problems as scaling and spatting in the progress of time. Therefore in this study it develop the performance Improving agent of concrete surface that can block a deterioration cause such as $CO_2$ gas, chloride ion and water from the outside and enhance waterproofing ability by reinforcing the concrete surface when applying it to concrete structures.

• Journal of Korean Society of Rural Planning
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• v.22 no.2
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• pp.19-29
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• 2016

Disasters that occur most frequently in rural areas are drought, flood, damages from wind and cold weather. Among these, damages from storm and flood and drought are the main disasters and recently, these are occurring on a large scale due to unusual weather conditions. Under such circumstances, projects and researches on disasters in rural areas are under way but they are mostly targeting one area or making approaches focusing on repair facilities, maintenance project of facilities in small streams, and disaster management, so there have not been enough studies on the current status of overall damaged facilities in the rural areas. Against this backdrop, through the analysis of the current status of damaged facilities due to storm and flood in rural areas, this study aims to provide base data for policies needed for disaster recovery planning and maintenance work of rural areas. For the analysis of damaged facilities due to storm and flood in rural areas, using the annual report on disasters issued by Ministry of Public Safety and Security and based on the occurrence rate of estimated damage in each city and district for the past 10 years(2004~2013), 8 areas with the highest number of occurrence and cost of damage were found from each province and target areas were selected. Then, regarding the selected target areas, the General Plan for Reducing Damages from Storm and Flood, which is the report on top-level plan for preventing disasters, was secured and the current status of damaged facilities were analyzed. After organizing the analysis of current status, the tendency of damaged facilities due to storm and flood in rural areas, the items of damaged facilities depending on the types of storm and flood damages, and risk factors were suggested. Based on this result, in order to generalize the results of follow-up researches, it is thought that disaster recovery planning and establishing the system of remodeling items necessary for maintenance work would be possible by analyzing damage investigation items recorded in additional researches on rural areas, researches on natural disasters, and recovery plan instructions and by conducting on-site investigation on the damaged villages from storm and flood in rural areas.

• Journal of the Korean Arthroscopy Society
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• v.4 no.2
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• pp.134-137
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• 2000

Purpose : To evaluate tile clinical results of resorbable meniscal arrow fixation for repairable meniscal tear with concurrent anterior cruciate ligament(ACL) reconstruction. Materials and Methods : Between April, 1997 and June, 1999, we performed resorbable meniscal arrow fixation and ACL reconstruction simultaneously for 18 cases of repairable meniscal tears with ACL injuries. Nine cases were acute injuries, 5 cases, subacute and 4 cases, chronic. The average follow-up was 21.5 months($12\~38$ months). Results : The healing rate was $89\%$ for acute injuries, $80\%$ for subacute injuries and $50\%$ for chronic injuries. Conclusion : Resorbable meniscal arrow fixation with concurrent ACL reconstruction is a good treatment modality for acute and subacute injuries.

• Journal of the Korean GEO-environmental Society
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• v.16 no.7
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• pp.35-42
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• 2015

Grouting method has been widely used for the ground improvement and stabilization: mostly to block or control the ground water in the early years and to improve the ground, repair the structure in recent years, ever increasing its use. Despite many advantages so far, the existing grouting method also has some shortcomings including uncertain permeation of grouting with gravity type if the voids between the soil particles are narrow, and problems due to the relaxation of the neighboring ground when injected using injection pressure. As an alternative, a vibration injection method with constant amplitude and frequency has been developed in recent years, with the vibration grouting being reported to have a permeability increasing effect of grout material compared with the positive pressure injection type. Accordingly, the purpose of this study is to investigate the improvement effect of the vibration grouting that applies short-period vibration energy by varying vibration cycle, vibration time and ground conditions to evaluate the strength enhancing effect of grouting materials, expansion effect of grouting body, ground improvement effect of the grouting and the penetration characteristics of the rock joint. The findings of this study show the improved compressive strength of grout, expansion of grouting body and increased penetration rate, according to the vibration compared with non-vibration under the loose soil condition.

• Clean Technology
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• v.27 no.4
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• pp.297-305
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• 2021

In the domestic aluminum industry, the extrusion process is a major process accounting for more than 40% of the total production. However, most domestic aluminum extrusion companies produce aluminum using old equipment that is more than 30 years old. Extrusion press is when the equipment is not replaced before the wear and breakage of major parts occur, reducing productivity and increasing the defect rate compared to new equipment. The old extrusion press often loses part drawings, so it is difficult to repair them properly on-site and to remanufacture them due to the lack of technical skills for maintenance. Therefore, a systematic remanufacturing plan must be designed from dismantling the equipment. In this study, remanufacturing FMEA was devised to remanufacture old extrusion press. The risk priority was analyzed by considering the degree of damage to the recycled parts, the cycle due to breakage/damage during the extrusion process, and the value of recycling resources due to remanufacturing. To standardize the remanufacturing process, remanufactured FMEA was performed through part analysis according to the structural analysis of the extrusion press. In addition, remanufacturing priorities were selected for each part, while remanufacturing itself was studied for efficiency of resource circulation and product quality stabilization.