• Restorative Dentistry and Endodontics
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• 제45권1호
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• pp.2.1-2.7
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• 2020

Objectives: This study aimed to evaluate the cell viability and migration of Endosequence Bioceramic Root Canal Sealer (BC Sealer) compared to MTA Fillapex and AH Plus. Materials and Methods: BC Sealer, MTA Fillapex, and AH Plus were placed in contact with culture medium to obtain sealers extracts in dilution 1:1, 1:2 and 1:4. 3T3 cells were plated and exposed to the extracts. Cell viability and migration were assessed by 3-(4,5-dimethylthiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and Scratch assay, respectively. Data were analyzed by Kruskal-Wallis and Dunn's test (p < 0.05). Results: The MTT assay revealed greater cytotoxicity for AH Plus and MTA Fillapex at 1:1 dilution when compared to control (p < 0.05). At 1:2 and 1:4 dilutions, all sealers were similar to control (p > 0.05) and MTA Fillapex was more cytotoxic than BC Sealer (p < 0.05). Scratch assay demonstrated the continuous closure of the wound according to time. At 30 hours, the control group presented closure of the wound (p < 0.05). At 36 hours, only BC Sealer presented the closure when compared to AH Plus and MTA Fillapex (p < 0.05). At 42 hours, AH Plus and MTA Fillapex showed a wound healing (p > 0.05). Conclusions: All tested sealers demonstrated cell viability highlighting BC Sealer, which showed increased cell migration capacity suggesting that this sealer may achieve better tissue repair when compared to other tested sealers.

• 한국구조물진단유지관리공학회 논문집
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• 제22권3호
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• pp.84-89
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• 2018

최근 자기치유 재료에 대한 연구는 보수하기 힘들거나, 보수비용이 많이 소요되는 구조물에 대해 구조물 스스로 손상을 치유하여 사용수명을 증가시키기 위해 많이 수행되어오고 있다. 현재 널리 사용되고 있는 자기치유 평가 방법으로는 투수시험이 있다. 하지만, 자기치유 평가 방법에서 자기치유 성능은 콘크리트의 초기 균열 폭에 큰 영향을 받지만 일관된 기준을 가지고 있지 않은 실정이다. 따라서, 본 연구에서는 기존 연구에서 사용한 균열 폭과 투수량을 기반으로 균열 폭-투수량의 상관관계와 시간-투수량의 상관관계를 분석하였다. 또한, 광학현미경을 이용하여 측정한 초기 균열 폭은 신뢰성이 떨어지므로 Poiseuille flow에서 ${\alpha}$값을 도출하여 시간-균열 폭에 대한 상관관계를 분석하여 시간-투수량과 시간-균열 폭에 대한 경향을 분석하였다.

• 한국콘텐츠학회논문지
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• 제6권1호
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• pp.80-84
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• 2006

모음을 삽입시키거나 자음을 탈락시킴으로써 한 음절 내의 영어 연속음을 없애는 자음군 축약 전략이 기존의 연구들마다 다르다는 점에 동기를 부여받아서 한국 학생들의 영어 자음군 축약 전략을 탐구하게 되었다. 대학생 60명의 어두와 어말 자음군 발음을 조사한 결과, 초성이냐 종성이냐 하는 운율적 위치와 자음군이 몇 개로 구성되어 있느냐는 자음군 숫자에 따라 모음 삽입이냐 자음 탈락이냐 하는 자음군 축약 전략에 영향을 미치는 것으로 나타났다. 삽입과 탈락의 오류 비율은 초성보다는 종성에서 높았고 두 개의 자음군보다는 세 개의 자음군에서 높았다. 전반적으로 삽입 오류 비율이 탈락 오류 비율보다 높았으나, 종성 위치의 세 개의 자음군에서는 탈락 비율이 삽입 비율보다 중요하게 높았다. 종성 위치 세 개의 자음군에서 탈락 비율이 높은 것 때문에 운율 위치에 상관없이 세 개의 자음군에서 삽입보다 탈락 비율이 높게 나타났으며 전반적으로 종성에서 탈락 비율이 높이 나타났다.

• Archives of Plastic Surgery
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• 제36권1호
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• pp.46-50
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• 2009

Purpose: Finger injury by green onion cutting machine is one of the common hand injuries in the kitchen. It has a unique feature: there are multiple parellel laceration 3 - 5 mm wide. There are two directions of injuries(vertical, oblique). It may involve bone, tendon, nerve, and vessel injuries. We discuss its management and the long - term progress. Methods: We have treated six patients from 2003 to 2007. We carried out low tension approximation with thin suture materials to avoid ischemia and performed the additional operation as nail bed repair, tenorrhaphy, open reduction, vessel anastomosis, and composite graft. We reviewed the record of initial injury and collected the follow - up record. Results: They were all middle aged - women who had worked in the kitchen. Right hand was dominent over left hand. The ratio of the directions was 3 : 3 (vertical : oblique). They were all competely healed although there were three atrophy, four hyperesthesia, and one nail deformity. Conclusion: Finger injury by green onion cutting machine is a unique pattern of laceration with various accompanied injuries. It may look like a severe form of injury, but in most cases have relatively favorable progress. We have to perform careful examination of accompanied injuries and carry out the proper management. First and foremost, the user especially in the middle aged women should be warned to be careful in handling this risky machine.

• Clinics in Shoulder and Elbow
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• 제14권1호
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• pp.134-139
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• 2011

목적: 광범위한 Hill-Sachs 병변을 동반한 전방 견관절 불안정성에 대한 관절경 하 Remplissage 술기를 고찰하고 저자들의 경험을 소개하고자 한다. 대상 및 방법: 골관절염이 없고, 견관절 주위의 골절이 없으며, 10회 이상의 재발성 탈구를 경험하였던 환자들 중에, 30~40% 이상의 광범위한 Hill-Sachs 병변 및 관절와 골 결손이 20% 미만인 경우를 대상으로 관절경 하 Bankart 병변 복원술과 함께 Remplissage 술기를 시행하였다. 결과 및 결론: 광범위한 Hill-Sachs 병변이 동반된 전방 견관절 불안정성에 대한 Remplissage 술기는 견관절의 안정성 및 임상적, 기능적으로 양호한 결과를 보여줄 수 있을 것으로 생각된다.

• Journal of Welding and Joining
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• 제28권3호
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• pp.79-85
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• 2010

Hardfacing is one of the frequently applying method to increase surface hardness in hot forging die. Recently, hardfacing receives great attention due to it's repair availability and low cost. In hot forging die, crack resistance and thermal shock resistance have been considered as major properties, However there are few studies for the assessment of these properties. So, it is necessary to establish the assessment method for crack resistance and thermal shock resistance in hardfacing for hot forging die. In this study, flux cored arc welding was applied to make hardfacing welds. Three point bending test was carried out to assess hardfacing weld's crack resistance, and high temperature bending test using salt bath was developed for thermal shock resistance. Consequently, it was possible to assess crack resistance and thermal shock resistance of hardfacing welds for hot forging die quantitatively.

• 대한음성언어의학회:학술대회논문집
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• 대한음성언어의학회 2003년도 제19회 학술대회
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• pp.183-183
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• 2003

Background and Objectives : Cartilage reconstruction is one of medical issue in otolaryngology. Tissue engineering is presently being utilized in part of cartilage repair. Sources of cells for tissue engineering are chondrocyte from mature cartilage and bone marrow mesenchymal stem cells that are able to differentiate into chondrocyte. Recent studies have shown that adipose tissue have mesenchymal stem cells which can differentiate into adipogenic, chondrogenic myogenic osteogenic cells and neural cell in vitro. In this study, we have examined chondrogenic potential of the canine adipose tissue-derived mesenchymal stem cell(ATSC). Materials and Methods : We harvested canine adipose tissue from inguinal area. ATSCs were enzymatically released from canine adipose tissue. Under appropriate culture conditions, ATSCs were induced to differentiate into the chondrocyte lineages using micromass culture technique. We used immunostain to type II collagen and toluidine blue stain to confirm chondrogenic differentiation of ATSCs. Results : We could isolate ATSCs from canine adipose tissue. ATSCs expressed CD29 and CD44 which are specific surface markers of mesenchymal stem cell. ATSCs differentiated into micromass that has positive response to immunostain of type II collagen and toluidine blue stain. Conclusion : In vitro, ATSCs differentiated into cells that have characteristic cartilage matrix molecules in the presence of lineage-specific induction factors. Adipose tissue may represent an alternative source to bone marrow-derived MSCs.

• 한국레이저가공학회지
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• 제14권2호
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• pp.17-23
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• 2011

Active thin films are ubiquitous in the manufacture of all forms of flat panel display (FPD). One of the most widely employed thin films is indium tin oxide (ITO) and metal films used electrically conductive materials in display industries. ITO is widely used for fabrication of LCD, OLED device, and many kinds of optical applications because of transparency in visible range and its high conductivity and metal films are also widely employed as electrodes in various electric and display industries. It is important that removing specific area of layer, such as ITO or metal film on substrate, to fabricate and repair electrode in display industries. In this work, we demonstrate efficient selective ablation process to ITO and aluminum film on glass using a femtosecond laser (${\lambda}p=1025nm$) respectively. The femtosecond laser with wavelength of 1025nm, pulse duration of 400fs, and the repetition rate of 100kHz was used for selectively removing ITO and Al on glass in the air. We can successfully remove the ITO and Al films with various pulse energies using a femtosecond laser.

• 한국도로학회논문집
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• 제14권1호
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• pp.17-24
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• 2012

본 연구에서는 다양한 실내시험을 통하여 국내에서 개발된 에폭시 아스팔트 혼합물의 공용성을 평가하였다. 최대입경 13mm의 밀입도 혼합물을 기초로 하여 아스팔트 바인더의 20% 또는 40%를 국산 및 일본산 에폭시 수지로 치환하여 4종류의 에폭시 아스팔트 혼합물의 배합 설계를 실시하였다. 에폭시 아스팔트의 가사시간이 에폭시 수지가 40% 사용한 경우 3시간, 20% 사용한 경우 6시간 정도임을 확인할 수 있었다. 휠트랙킹 시험, 간접인장 반복시험, 그리고 저온 휨 시험 결과 국산 및 일본산 에폭시 아스팔트 혼합물의 공용성이 일반 아스팔트 혼합물 보다 상당히 우수한 것으로 나타났다. 하지만 일부 에폭시 아스팔트 혼합물에서는 수분손상 가능성을 확인할 수 있었다. 또한 일본산 에폭시 아스팔트 혼합물과 국산 에폭시 아스팔트는 유사한 성능을 나타냈다. 또한 콘크리트 보수재로 개발한 국산 에폭시 아스팔트의 적합성을 평가하기 위하여 추가적으로 열팽창계수, 부착강도, 인장강도를 측정한 결과, 일반 콘크리트와의 부착력은 우수하고 인장강도는 유사한 것으로 나타났으나 열팽창계수는 5배정도 큰 것으로 나타났다.

• Journal of Chest Surgery
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• 제16권4호
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• pp.584-593
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• 1983

Esophageal reconstruction was performed in 344 patients with irreversible stricture of the esophagus resulting from caustic burns at National Medical Center from 1959 to 1982.There were 113 males and 231 females, and ranging from 2.5 to 58 years of age, and mean age was 26.5 years, and 25 cases were less than 10 years old. Caustic materials were 286 [83.2%] alkali and 50[14.5%] acid. The most frequent stricture site was upper thoracic esophagus as 56.7%, and the next was cervical as 31.4%, and lower, 11.9%. The stomach was involved in 10.8% totally, and hypopharyngeal stricture was also noticed in 3.2%, and in 3 cases, hypopharyngeal reconstruction was needed due to extensive scar change. In 329 of total 344 cases, colon interposition was performed without resection of the strictured esophagus except 4 cases which were complicated T-E fistula or perforation, and most of them, about 10-15 cm of terminal ileum with right half of the colon was used as the graft. The left colon with anti-peristalsis was used as graft only in 30 cases. The most common postoperative complication was anastomotic leak as 16.7% of total cases, and it was 12.5% from neck, 3.3% from ileocolostoma and 0.9% from cologastrostoma. Next common complication was neck stenosis [8.8%], aspiration pneumonia [6.4%], and graft necrosis [3.9%] in order. Overall operative mortality was 5.5% [14/329], and main causes of death were graft necrosis, sepsis due to anastomotic leak, gastric bleeding, and intestinal obstruction. Besides of colon interposition, according to shape or level of the stricture, plastic repair or segmental resection and direct anastomosis was done in 9, and 1 of them were complicated stenosis at the anastomotic site. In lower stricture, esophagogastrostomy was done in 10 cases, and 1 case expired due to hepatitis, and anastomotic stenosis was occurred in 2 cases at 1.5 months and 2.4 years later. During follow-up of 298 cases colon interposition from 6 months to 22 years, 82.6% was excellent, and 2.9% was complained of mild discomfort, and 4 cases were dead laterly, but 3 of them were not related to reconstruction.