• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.37-45
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• 2015

In this experimental study, effect of milled glass fibers was investigated on corrosion resistance of PSC grout mortar. In order to check whether the mortar mixture with milled glass fibers satisfy the required properties as a PSC grout, time of flow, bleeding and compressive strength measured. The corrosion resistance were investigated through chloride ion migration test, mortar absorption test and surface resistivity measurement. It is confirmed that all proportions with milled glass fibers have better corrosion resistance than that with only OPC binder. Time of flow was reduced but the bleeding was increased to unacceptable level by using milled glass fibers. Consequently, the mix proportion with milled glass fibers for a PSC grout should be modified to have lower water/binder ratio.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.275-282
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• 2002

High fluidity concrete needs high dosage of superplasticizer to acquire sufficient fluidity and high contents of fine powder and viscosity agents to prevent segregation. But it requires high manufacturing cost and has difficult in quality control. Therefore, in this paper, determination of optimal mixture proportion of segregation type superplasticizer for high fluidity concrete and manufacturing high fluidity concrete by applying developed segregation reducing type superplasticizer are discussed using flowing concrete method. According to test results, as dosage of superplasticizer increases, it shows that fluidity and bleeding increase, while air contents and ratio of segregation resistance decrease. It also shows that adding viscosity agent into it reduce bleeding and improve segregation resistance. Dosage of AE agent into it containing viscosity agent recovers loss of air contents during flowing procedure. Combination of proper contents of superplasticizer, viscosity agent and AE agent make possible to develope segregation reducing type superplasticizer Compressive strength of high fluidity concrete applying flowing method with it is higher than that of base concrete. No differences of compressive strength between compacting methods are found.

• Journal of Chest Surgery
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• v.56 no.5
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• pp.346-352
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• 2023

Background: A significant proportion of cardiac surgery intensive care unit (CSICU) patients require long-term ventilation, necessitating tracheostomy placement. The goal of this study was to evaluate the long-term postoperative outcomes and complications associated with percutaneous dilatational tracheostomy (PDT) in CSICU patients. Methods: All patients undergoing PDT after cardiac, thoracic, or vascular operations in the CSICU between January 1, 2013 and January 1, 2021 were identified. They were evaluated for mortality, decannulation time, and complications including bleeding, infection, and need for surgical intervention. Multivariable regression models were used to identify predictors of early decannulation and the complication rate. Results: Ninety-three patients were identified for this study (70 [75.3%] male and 23 [24.7%] female). Furthermore, 18.3% of patients had chronic obstructive pulmonary disease (COPD), 21.5% had history of stroke, 7.5% had end-stage renal disease, 33.3% had diabetes, and 59.1% were current smokers. The mean time from PDT to decannulation was 39 days. Roughly one-fifth (20.4%) of patients were on dual antiplatelet therapy and 81.7% had anticoagulation restarted 8 hours post-tracheostomy. Eight complications were noted, including 5 instances of bleeding requiring packing and 1 case of mediastinitis. There were no significant predictors of decannulation prior to discharge. Only COPD was identified as a negative predictor of decannulation at any point in time (hazard ratio, 0.28; 95% confidence interval, 0.08-0.95; p=0.04). Conclusion: Percutaneous tracheostomy is a safe and viable alternative to surgical tracheostomy in cardiac surgery ICU patients. Patients who undergo PDT have a relatively short duration of tracheostomy and do not have major post-procedural complications.

• Journal of Korean society of Dental Hygiene
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• v.23 no.1
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• pp.73-82
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• 2023

Objectives: This study aimed to evaluate the oral symptoms experiences of Korean adolescents among multicultural families. Methods: Data on 985 participants from the 16th Korea Youth Risk Behavior Web-based Survey were collected and analyzed using complex sample descriptive statistics. Results: The foreign-born mother, foreign-born parents, and foreign-born father rates were 77.2%, 17.3%, and 5.4%, respectively. The toothache, gingival bleeding, tooth fracture, and tooth sensitivity experience rates were 21.3%, 18.8%, 13.3%, and 30.4%, respectively. The tooth fracture rate was highest in the foreign-born parents group (24.6%). The toothache odds ratio (OR) was 1.71 (95% CI: 1.24-2.37) times higher in girls. The foreign-born mother group was 2.47 (95% CI: 1.09-5.60) times higher than that of the foreign-born father or both parents foreign-born groups. The smoking group was 2.03 (95% CI: 1.20-3.43) times higher than that of the non-smoking group. The gingival bleeding OR was 5.11 (95% CI: 1.80-14.53) times higher in the lowest economic status group. The tooth fracture OR was 3.44 (95% CI: 1.01-11.70) times higher in the lowest economic status group. The tooth sensitivity OR was 1.53 (95% CI: 1.14-2.04) times higher in girls. Conclusions: It is necessary to establish a program to promote oral health of adolescents from multicultural families.

• Land and Housing Review
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• v.14 no.2
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• pp.137-145
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• 2023

In this study, the characteristics such as flowability, bleeding rate, and strength of the CLSM (Controlled Low Strength Material) according to physical properties such as particle size distribution and particulate content of the pond ash were investigated as part of the practical development of technology for CLSM using pond ash. As a result of analyzing the properties of the collected pond ash, it was found that the density and particle size distribution characteristics were different. And that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for four hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it was determined that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.133-138
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• 1976

The author reviewed 263 cases of pulmonary tuberculosis operated on at the Department of Thoracic Surgery, Seoul National University Hospital during the 19 year period, from January, 1957 to December 1975. Following observations were made: 1) The sex ratio was 2.8: 1 in male's favor, and 83.6% of the patients were between 20 and 49 years of age. 2) The trends in operative procedures revealed that surgical collapse as a definitive therapy of pulmonary tuberculosis has virtually disappeared and operations required for residuals of pleural diseases have increased. 3) The overall hospital mortality rate was 3-8%. The highest mortality rate was encountered in the cases of resection and decortication with 28.6%, 4) The rate of overall postoperative complications was 24.7%, the highest being encountered in decortication with 56.4%. 5) The most frequent cause of death was bleeding, while the dead space was the most frequent complication.

• Journal of Chest Surgery
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• v.28 no.9
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• pp.842-846
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• 1995

Recently, the trauma patients have been markedly increasing due to the vast increase of traffic accident, industrial disaster, incidental accident and violence. The authors have analysed of 22 patients of thoracic injuries combined with abdominal injuries and summarized as follows. The ratio of male to female was 3.4:1 and their age distribution was from 5 years to 68 years and mean age was 34.4 years. The etiologies of injury were traffic accident, stab wound, fall down and violence. Associated injuries were fractures, bowel perforation, kidney rupture, head injury, liver laceration, spleen rupture and so forth. The modes of treatment were closed thoracostomy, repair of diaphragm, ruptured bowel repair, explo-thoracotomy, splenectomy, hepatic lobectomy in this order of frequency. The postoperative complications were atelectasis, wound infection, pneumonia, empyema, acute renal failure, respiratory failure and bleeding. The mortality rate was 13.6% [3/22 and the causes of death were respiratory failure 1 case, acute renal failure 1 case and hypovolemic shock 1 case.

• Proceedings of the Korea Concrete Institute Conference
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• 1989.10a
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• pp.15-20
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• 1989

The effect of superplasticizing agents on the sorkability performance in fresh concrete have been analyzed and investigated under various mix proportions of water cement ratio of 0.40, 0.50, 0.60 and 0.70, superplasticizing agents of NL-4000 and Rheobuild-716, and addition rate of sp. agents of 0.0, 0.5, 1.0, 1.5 and 2.0 in the practical range. It is the aim of this study to provide the fundamental data on the fluidity performance and workability improvement of superplasticized concrete such as time-dependent change of slump, flow value and compacting factor, air content, bleeding, mixing temperature and setting rate of fresh concrete comparing with base concrete and conventional concrete for the practical use and research data accumulation of superplasticized concrete in the side of development of concrete construction technology and management.

• Journal of Chest Surgery
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• v.15 no.1
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• pp.3-12
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• 1982

Although most patients with penetrating injuries can be managed successfully with early tube thoracotomy, blood volume replacement & close observation, the remainder can be saved only by an aggressive operative intervention. From January 1959, to August 1980, 176 cases with penetrating injuries had been treated at the Department of Cardiothoracic Surgery, National Medical Center. The ratio of male to female patient of penetrating chest wounds was 4.3:1 in male predominance and age from 10 to 40 occupied 76.7% of the total cases. Stab wounds was the most common penetrating injuries and followed by gunshot & glass wounds. To prevent early complications of penetrating chest injuries, thoracentesis were done in 29 cases [16%], and closed thoractomy in 40 cases [22.7%]. Open thoractomy, however, had to be done in 37 cases [21%] because of massive bleeding, hemopericardium, foreign body.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.780-785
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• 1984

We had studied 20 cases of VSD patients whose murmur was sustained after open heart surgery from 1977 to 1984. The postoperative cardiac catheterization was performed on post-op. 20th day. Their ages ranged from 5 to 25 years old. Among them, 4 patients had significant residual shunt which required reoperation. [1 patient; re-op, 3 patient; refused]. Sex ratio was 13:7 in male and female. Associated anomalies were PDA, ASD, Pulmonary stenosis, Mitral insufficiency. Except 1 case, all of them was Kirklin type II VSD. Postoperative complications were I RBBB, residual shunt, cardiac tamponade due to bleeding, wound infection. Preoperative pulmonary artery systolic pressure was highly related to residual shunt in our study. Postoperative LVEDV returned to normal range on the 3rd week.