• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.3
• /
• pp.509-516
• /
• 2005

For the purpose of comparing the bond strengths of compomers to composite resin, composite Z250, and two polyacid modified composite resin, Dyract AP and F2000, were selected and investigated using universal testing machine for measuring the shear bond strengths. Additionally, the failure modes were examined by observing the fractured surfaces of each specimen. The following results were obtained. 1. The shear bond strength of Dyract AP to Z250 were higher than those of F2000, but there was no statistically significant difference between group 1 and group 3(p>0.05), and groups using fresh compomers showed higher bond strength than those using aged compomers(p<0.05). 2. After measuring the shear bond strength of each group, it was highest in group 5 and was lowest in group 9(p<0.05). 3. Although there was no statistically significant difference, groups treated with thermocycling showed lower bond strengths than those of non-thermocycling groups. 4. Overall compomer/composite resin failures were adhesive. Cohesive failures occurred mainly in groups using bonding agent. Based on these results, the application of a bonding agent on fresh polyacid-modified resin composite increases the bond strength between polyacid-modified resin composite and composite resin. Additionally, the surface of aged polyacid-modified resin composite has to be roughened mechanically and a bonding agent has to be used in combination with composite resin.

• Journal of Chest Surgery
• /
• v.34 no.6
• /
• pp.477-484
• /
• 2001

Background: Initial symptoms for esophageal perforation have not been clarified, but when there is no early diagnosis and proper treatment to follow immediately after the diagnosis, it is fatal for the patients. Therefore, this study attempted to discover the factors that influence the prognosis of esophageal perforation to contribute to the improvement of the treatment result. Material and Method: The subjects of this study are 32 patients who came to the hospital with esophageal perforation from October, 1984 to June, 2000. This study examined the items for clinical observation such as patients' sex, age, cause of the perforation, perforation site, the time spent until the beginning of the treatment, symptoms caused by the perforation and its complication, and treatment methods. This study tried to find out the relationship between the survival of patients and each item. Result: There were 24 male and 8 female patients and their mean age was 49.7+16.4. For the causes of perforation, there were 14 cases(43%) of iatrogenic perforation, which ranked first, caused by the medical instrument operation and surgical damage. As for the perforation sites, thoracic esophagus was the most common site(26 cases of 81.2%) and chest pain was the most frequent symptom. The complication caused by esophageal perforation showed the highest cases in the order of mediastinitis, empyema, sepsis and peritonitis. After the treatment, there were 23 cases of survival and 9 cases of mortality. The total mortality rate was 28.1% and the main causes of mortality were sepsis and acute respiratory distress syndrome(ARDS). As for the treatment, 8 cases(25.0%) treated the perforation successfully using conservative treatment only. As for the surgical treatment, there were 5 cases(15.6%) of cervical drainage, 7 cases (21.8%) of primary repair and 12 cases(37.5%) of esophageal reconstruction after performing an exclusion-diversion. There were 18 cases(56.2%) of complete treatment of esophageal perforation at its initial treatment and in 14 cases(43.8%) of treatment failure at its initial treatment, patients were completely cured in the next treatment stage or died during the treatment. The cases of perforation in thoracic esophagus, complication into severe mediastinitis or sepsis and the cases of failure at initial treatment showed a statistically significant mortality rate (p<0.05).

• Journal of Chest Surgery
• /
• v.34 no.12
• /
• pp.901-908
• /
• 2001

Background : Coronary artery bypass graft(CABG) in patients with advanced left ventricular dysfunction has often been regarded as having high mortality rate, despite the great improvement in operative result of CABG. With recent advances in surgical technique and myocardial protection, surgical revascularization improved the symptom and long-term survival of these high risk patients more than the medical conservative treatment. Material and Methold : Clinical data of 31(4.1％) patients with preoperative ejection fraction less than 30% among 864 CABGs performed between January 1995 and March 1999 were retrospectively analyzed and pre- and postoperative changes of the ejection fraction on echocardiography were analyzed. There were 26 men and 5 women. The mean age was 60.7 years(range 41 to 72 years). History of myocardial infarction(30 cases, 98％) was the most common preoperative risk factor. There were seven irreversible myocardial infarction on thallium scan. Most patients had triple vessel diseases(26 cases, 84％) and first degree of Rentrop classification(16 cases, 52％) on coronary angiography. The mean number of distal anastomosis during CABG was per patient was 4.9${\pm}$0.8 sites in each patient. In addition to long saphenous veins, the internal mammary artery was used in 20 patients. Total bypass time was 244.7${\pm}$3.7 minutes(range, 117 to 567 minutes), and mean aortic cross-clamp time was 77.9 ${\pm}$ 1.6 minutes(range, 30 to 178 minutes). There were five other reparative procedures such as two left ventricular aneurysrmectomy, two mitral repair, and one aortic valve replacement. There were twelve postoperative complications such as three cardiac arrhythmia, two bleeding(re-operation), one delayed sternal closure, eleven usage of intra-aortic balloon counterpulsation for low cardiac output. Two patients died, postoperative mortality was 6.5% . Twenty-nine patients were relieved of chest pain and left ventricular ejection fraction after operation was significantly higher(38.5${\pm}$11.6%, p 0.001) as compared with preoperative left ventricular ejection fraction(25.3${\pm}$2.3%). The follow up period of out patient was 25. 3 months. Conclusion: In patients with coronary artery disease and advanced left ventricular dysfunction, coronary artery bypass grafting can be performed relatively safely with improvement in left ventricular function, but it will be necessary to study long term results.

• Journal of Chest Surgery
• /
• v.37 no.5
• /
• pp.401-409
• /
• 2004

Background: As the rupture of chordae and/or papillary muscle became the main cause of mitral valve regurgitation, mitral reconstructive surgery has a very important role. In this regard, we analyzed the clinical result and postoperative early result of operative treatment performed in our hospital, Material and Method: For this analysis, forty nine patients (male 26, female 23, mean age 49.0$\pm$16.5) who underwent mitral valve operation caused by the rupture of chordae and/or papillary muscle from August 1991 to April 2002 were reviewed. Among forty nine patients, twenty two (44.9%) received mital valve reconstruction and twenty seven (59.2%) received mitral valve replacement. Result: As to the pathological etiology of rupture of mitral and papillary muscle, twenty five cases (51.0%) were nonspecific degeneration, eleven cases (22.4%) were myxomatous degeneration, seven cases (14.3%) were subacute bacterial endocarditis. Three patients suffered mortality after operation (6.1%) and valve replacement was performed again on one patient because of remnant mitral insufficiency after valve reconstruction. The 5-year survival rate after operation for the entire mitral valve regurgitation patients was 81 .4%. We have also compared and analyzed the operation results of a group of patients who underwent valve reconstruction and the other group of patients who underwent valve replacement from thirty six patients who had suffered from mitral valve regurgitation caused by degenerative disease. The mortalities were 0% and 14.3%, respectively and the 5-year survival rates were 90.2% and 64.3%, respectively, but there were no statistical significance. Conclusion: The most common pathological etiology of mitral valve regurgitation caused by rupture of chordae and/or papillary muscle was nonspecific degeneration, In case of degenerative disease is the cause of mitral valve regurgitation, valve reconstruction showed better long-term effects in many respects and better operation results compared to valve replacement.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.31 no.4
• /
• pp.113-122
• /
• 2013

In this study, the traditional structure of the impact on the stability analysis. Korean traditional landscape architecture column space of stonework stable composition as the foundation of the fence for a long time been known to fall down and not maintained. The destination of research Ohgokmun Damyang Soswaewon fence which is in harmony with nature is one of the traditional structures that affect its shape without being kept so far came true. This includes our ancestral wisdom and that wisdom can guess guesswork. But I let the traditional reproduction incidence structures frequently. This deviation from the traditional method of construction application of shorthand stand. Thus, the subject of this study, the factors that do not fall down fences Ohgokmun solution is to indirectly gain the weak. In addition, epidemiological studies and the methods of calculation of the inferred physical examination, the results of the analysis were derived through the following. First, the internal factors of the fence Ohgokmun constituting the structural member and the coupling of the scheme. 1) based on stable ground. Greater role in the country rock The fact that the settlement will have no symptoms. 2) to minimize the friction caused by hydrological water to remove the two-pronged process through stone work building form and menu sustaining power in hydrology and flooding made against the bypass channel. 3) due to the load bearing capacity and durability to withstand the strength of the material and the construction of structures in the form of a dispersion of power between each individual to maximize the process of getting traction was applied. Second, external factors Ohgokmun fence the results obtained through the calculation of the dynamics of repair, is greatly affected by the wind and the water gate of the fence, but the action of the structural stability of the lack of power that hurt enough conclusion. In this study, the results of the structure of internal and external influence as well through the structure can be viewed as composed consisting. However, over the next follow-up in terms of climate and environmental factors due to the fact that the fall might.

• Korean Journal of Heritage: History & Science
• /
• v.51 no.4
• /
• pp.146-169
• /
• 2018

Artificial or natural artifacts, which have historical, artistic, academic or scenic value as national, ethnic or global assets, are designated as "cultural heritages" under the Act on the Protection of Cultural Heritage. Cultural heritages can be divided into tangible cultural heritages, intangible cultural heritages, and monument and folklore heritages. In addition, depending on the object of designation, a cultural heritage can be designated either as a city or a provincial cultural heritage or a cultural heritage material, by a city mayor or provincial governor, and as a state-designated heritage by the administrator of the Cultural heritage Administration. The regular survey is a part of the policy for the preservation and management of state-designated heritages, which requires that surveys be undertaken every three to five years for the preservation, repair and maintenance of cultural heritages. It was stipulated in the Act on the Protection of Cultural Heritage in 2006, and since then has substantially contributed to the preservation and management of state-designated heritages based on the identification of damage to cultural heritages and the application of appropriate treatment measures. However, some parts of the guidelines on the regular survey, legislated in 2006, occasionally give rise to confusion in managing the regular survey system of state-designated movable cultural heritages, and need to be modified to facilitate the systematic management and improvement of the regular survey system. This study attempts to analyze the structure and operation of the regular survey system of state-designated movable cultural heritages, and proposes plans for improving the way of specifying each department which leads, manages and executes the regular survey, the process of entrusting the survey, and its guidelines and forms. I hope that these plans concerning the regular survey of state-designated movable cultural heritages will contribute to improving the quality and management of the system.

• Journal of Environmental Impact Assessment
• /
• v.28 no.4
• /
• pp.387-399
• /
• 2019

This research aimed to prepare the classification of the damage types and the damage rating system of noise barriers for expressway noise barriers and to develop deterioration evaluation method of noise barriers by reflecting them. The noise barrier consists of soundproof panels, foundations and posts and the soundproof panels with 10 different types of materials are used in a single or mixed form.In this paper, damage of soundproof panel shows a single or composite damage, and thus a evaluation model of deterioration has been developed for noise barriers that can reflect the characteristic of noise barriers. Materials used mainly for soundproof walls were divided into material types for metal, plastic, timber, transparent and concrete. And damage types for noise barrier were classified into corrosion, discoloration, deformation, spalling and dislocation and damage types were subdivided according to the noise barrier's components and materials. Damage rating was divided into good, minor, normal and severe for each major part of noise barrier to assess damage rating of soundproof panel, foundation and post. The deterioration degree of noise barrier was evaluated comprehensively by using the deterioration evaluation method of whole noise barrier using weighted average. Deterioration evaluation method that can be systematically assessed has been developed for noise barrier using single or mixed soundproof panel and noise barrier with single or complex damage types. Through such an evaluation system, it is deemed that the deterioration status of noise barrier installed can be systematically understood and utilized for efficient maintenance planning and implementation for repair and improvement of noise barriers.

• Journal of Korea Water Resources Association
• /
• v.56 no.2
• /
• pp.103-113
• /
• 2023

The river confluence is a section in which two rivers with different topographical and hyrodynamic characteristics are combined into one, and it is a section in which rapid flow, inflow of sediments, and hydrological topographic changes occur. In the confluence section, the flow of fluid occurs due to the difference in density due to the type of material or temperature difference, which is called a density flow. It is necessary to accurately measure and observe the confluence section including a certain section of the main stream and tributaries in order to understand the mixing behavior of the water body caused by the density difference. A comprehensive analysis of this water mixture can be obtained by obtaining flow field and flow rate information, but there is a limit to understanding the mixing of water bodies with different physical properties and water quality characteristics of rivers flowing with stratigraphic flow. Therefore, this study attempts to grasp the density flow through the water temperature distribution in the confluence section. Among the extensive data of the river, vertical data and water surface data were acquired, and through this, the stratification phenomenon of the confluence was to be confirmed. It was intended to analyze the mixed pattern of the confluence by analyzing the water mixing pattern according to the water temperature difference using the vertical data obtained by measuring the repair volume by installing the ADCP on the side of the boat and measuring the real-time concentration using YSI. This study can supplement the analysis results of the existing water quality measurement in two dimensions. Based on the comparative analysis, it will be used to investigate the current status of stratified sections in the water layer and identify the mixing characteristics of the downstream section of the river.

• Journal of Chest Surgery
• /
• v.30 no.5
• /
• pp.471-478
• /
• 1997

Introduction: The use of rabbits as a cardiopulmonary bypass(CPB) animal model is extremely dif%cult mainly due to technical problems. On the other hand, deep hypothermic circulatory arrest(CA) is used to facilitate surgical repair in a variety of cardiac diseases. Although steroids are generally known to be effective in the treatment of cerebral edema, the protective effects of steroids on the brain during CA are not conclusively established. Objectives of this study are twofold: the establishment of CPB technique in rabbits and the evaluation of preventive effect of steroid on the development of brain edema during CA. Material '||'&'||' Methods: Fifteen New Zealan white rabbits(average body weight 3.5kg) were divided into three experimental groups; control CA group(n=5), CA with Trendelenberg position group(n=5), and CA with Trendelenberg position + steroid(methylprednisolone 30 mglkg) administration group(n=5). After anesthetic induction and tracheostomy, a median sternotomy was performed. An aortic cannula(3.3mm) and a venous ncannula(14 Fr) were inserted, respectively in the ascending aorta and the right atrium. The CPB circuit consisted of a roller pump and a bubble oxygenator. Priming volume of the circuit was approximately 450m1 with 120" 150ml of blood. CPB was initiated at a flow rate of 80~85ml/kg/min, Ten min after the start of CPB, CA was established with duration of 40min at $20^{\circ}C$ of rectal temperature. After CA, CPB was restarted with 20min period of rewarming. Ten min after weaning, the animal was sacrif;cod. One-to-2g portions of the following tissues were rapidly d:ssected and water contents were examined and compared among gr ups: brain, cervical spinal cord, kidney, duodenum, lung, heart, liver, spleen, pancreas. stomach. Statistical significances were analyzed by Kruskal-Wallis nonparametric test. Results: CPB with CA was successfully performed in all cases. Flow rate of 60-100 mlfkgfmin was able to be maintained throughout CPB. During CPB, no significant metabolic acidosis was detected and aortic pressure ranged between 35-55 mmHg. After weaning from CPB, all hearts resumed normal beating spontaneously. There were no statistically significant differences in the water contents of tissues including brain among the three experimental groups. Conclusion: These results indicate (1) CPB can be reliably administered in rabbits if proper technique is used, (2) the effect of steroid on the protection of brain edema related to Trendelenburg position during CA is not established within the scope of this experiment.

• Journal of Chest Surgery
• /
• v.39 no.8 s.265
• /
• pp.588-597
• /
• 2006

Background: The surgical repair of a tetralogy of Fallot (TOF) has been performed successfully with a favorable early and late outcome. However, the later development of pulmonary regurgitation and stenosis remains a problem. The development of pulmonary regurgitation and stenosis may be changed by the size of right ventricular outflow tract (RVOT) reconstruction at the initial total correction. Hence, it is necessary to investigate the ideal size of RVOT reconstruction. Material and Method: This prospective study was carried out to determine how a surgical strategy and the RVOT size affect the occurrence of pulmonary regurgitation and stenosis. From January 2002 to December 2004, 62 patients underwent the TOF total correction. The RVOT size (diameter of pulmonary valve annulus) of each case was measured after the RVOT reconstruction and converted to a Z value. A pre-scheduled follow up (at discharge, 6 months, 1 year, 2 years and 3 years) was carried out by echocardiography to evaluate the level of pulmonary regurgitation and stenosis. Result: The patients were divided to two groups (transannular group n=12, nontransannular group n=50) according to the method of a RVOT reconstruction. The Z value of RVOT=iameter of pulmonary valve annulus) (transannular group -1, $range\;-3.6{\sim}-0.8;$ nontransannular group -2.1, $range\;-5.2{\sim}-1.5)$ and the average pRV/LV after surgery ${(transannular group 0.44{\pm}0.09,\;nontransannular group\;0.42{\pm}0.09)}$ did not show any significant difference between two groups. The occurrence of pulmonary regurgitation above a moderate degree was more frequent in the transannular group (p<0.01). In nontransannular group, the development of pulmonary regurgitation more than moderate degree occurred to the patients with larger RVOT size (Z value>0, p<0.02) and the progressing pulmonary stenosis more than mild to moderate degree developed in the patients with smaller RVOT size (Z value<-1.5, p<0.05). A moderate degree of pulmonary stenosis developed for 4 nontransannular patients. Three underwent additional surgery and one underwent a balloon valvuloplasty. Their Z value of RVOT were -3.8, -3.8 -2.9, -1.8, respectively. Conclusion: When carring out a TOF total correction, transannular RVOT reconstruction group has significantly more pulmonary regurgitation. In the nontransannular RVOT reconstruction. the size of the RVOT should be maintained from Z value -1.5 to 0. If the Z value is less than -1.5, we should follow up carefully for the possibility of pulmonary stenosis.