• BMB Reports
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• 제34권6호
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• pp.489-495
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• 2001

DNA damage by UV and environmental agents are the major cause of genomic instability that needs to be repaired, otherwise it give rise to cancer. Accordingly, mammalian cells operate several DNA repair pathways that are not only responsible for identifying various types of DNA damage but also involved in removing DNA damage. In mammals, nucleotide excision repair (NER) machinery is responsible for most, if not all, of the bulky adducts caused by UV and chemical agents. Although most of the proteins involved in NER pathway have been identified, only recently have we begun to gain some insight into the mechanism by which proteins recognize damaged DNA. Binding of Xeroderma pigmentosum group C protein (XPC)-hHR23B complex to damaged DNA is the initial damage recognition step in NER, which leads to the recruitment of XPA and RPA to form a damage recognition complex. Formation of damage recognition complex not only stabilizes low affinity binding of XPA to the damaged DNA, but also induces structural distortion, both of which are likely necessary for the recruitment of TFIIH and two structure-specific endonucleases for dual incision.

• 대한치과기공학회지
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• 제46권1호
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• pp.15-19
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• 2024

An ideal post material should have physical properties similar to those of dentin. Post materials with high elastic moduli may cause root fractures. This clinical report describes the treatment of a severely damaged tooth using a recently introduced material. Polyetherketoneketone (PEKK) is a semicrystalline high-performance thermoplastic polymer. PEKK is a promising material for custom post-and-core fabrication because of its elasticity close to that of dentin, good shock absorbance, machinability, and low cost. A laboratory scanner was used to digitize the conventional impression of a severely damaged maxillary right first molar. A custom PEKK post-and-core was designed and milled using computer-aided design and computer-aided manufacturing technology. Using the proposed technique, a custom PEKK post-and-core was fabricated accurately and human error was reduced. Restoration was luted with resin cement. Custom PEKK post-and-core restorations are a viable alternative for treating severely damaged teeth.

• 한국안전학회지
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• 제16권3호
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• pp.31-34
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• 2001

Cause of Bucheon LPG refueling station accident could not be clearly verified because of opposite talking of men reponsible for the accident the accident, damaged by BLEVE and fire, and no systematic fire investigation. After two and half years, recently first judgement has been carried out. But competitive arguement is going on and first leak point of massive LPG will not be clearly identified with evidences acquired by now. This accident gave us many instructions and advices. Specially, massive LPG leak can result in pool fire and safety of underground-installed storage tank is proved by no damage in the strong BLEVE.

• 한국환경복원기술학회지
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• 제13권4호
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• pp.65-74
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• 2010

This study is for Hanbuk Mountain Range within Gyeonggi province which is to propose the conservation plan by each damage pattern through site survey of the mountain range. The damage patterns are classified by siding, pointing and lining. The total damaged area is 103 areas: The siding pattern is damaged by developing farmland, mineral and quarry mining, dam, large scale development complex and cemetery park; The pointing pattern is including the development of road, transmission tower and way and mountaineering trail; The construction of electricity and communication facility, military facility, mobile communication station, heliport and shelter. The damages by developing road and large scale development complex are the most cause, and military facility, dam and reservoir, and residential area are the main causes, respectively. One of the compromised situation Hanbuk-Mountain Range usage as per section 7 section (18.45%), 12 section (18.45%) is the largest number of compromised has been surveyed, undermine the situation if you look at the usage by the road 25 locations (24.22%), military facilities and dam and reservoir to undermine this 11 established respectively (10.68%) were the most undermine. Therefore, this research propose the conservation plan as follow: first, need to understand, educate and publicize on Hanbuk-Mounatin Range; second, manage through the regulations and ordinance of Gyeonggi province; third build and expand the law for protecting Baekdu-Great Mountain Range.

• Steel and Composite Structures
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• 제29권6호
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• pp.689-701
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• 2018

Corrosion of steel reinforcement is a principal cause of deterioration of RC columns. Making these corrosion-damaged columns conform to new safety regulations and functions is a tremendous technological challenge. This study presented an experimental investigation on steel-concrete jacketed corrosion-damaged RC columns. The influences of steel jacket thickness and concrete strength on the enhancement performance of the strengthened specimens were investigated. The results showed that the use of steel-concrete jacketing is efficient since the stub strengthened columns behaved in a more ductile manner. Moreover, the ultimate strength of the corrosion-damaged RC columns is increased by an average of 5.3 times, and the ductility is also significantly improved by the strengthening method. The bearing capacity of the strengthening columns increases with the steel tube thickness increasing, and the strengthening concrete strength has a positive impact on both bearing capacity, whereas a negative influence on the ductility. Subsequently, a numerical model was developed to predict the behavior of the retrofitted columns. The model takes into account corrosion-damage of steel rebar and confining enhancement supplied by the steel tube. Comparative results with the experimental results indicated that the developed numerical model is an effective simulation. Based on extensive verified numerical studies, a design equation was proposed and found to predict well the ultimate eccentric strength of the strengthened columns.

• 대한한방내과학회지
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• 제32권1호
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• pp.43-55
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• 2011

Objectives : Sokmyeung-tang(SMT) has been used for treatment of CVA in traditional oriental medicine, so this study was designed to evaluate the effect of SMT's protection on brain cell damage against the oxidative stress that was affected by CVA, We also investigated the effect of motor function improvement and neurotrophic factor in ischemic cerebral damaged rats. Methods : We measured cell viability after administrating SMT, chemicals(Paraquat, SNP, rotenone, and $H_2O_2$) which cause oxidative stress, and both SMT and chemicals. We carried out neurobehavioral evaluation(Rotarod test, Beam-walking test, postural reflex test) and observed BDNF (brain-derived neurotrophic factor) expression by injecting SMT into ischemic cerebral damaged rat. Results : Through this study, we observed the following three results. First, brain cell death caused by paraquat, rotenone, and $H_2O_2$ significantly decreased with the treatment of SMT. Second, neuronal movement function in ischemic cerebral damaged rats was significantly improved by the treatment of SMT. Third, BDNF in ischemic cerebral damaged rats increased with the treatment of SMT. Conclusions : SMT protects brain cells from damage induced by oxidative stress (Paraquat, rotenone, $H_2O_2$). SMT also improves neuronal movement function and increases BDNF in ischemic cerebral damaged rats.

• 한국화재소방학회논문지
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• 제20권2호
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• pp.54-63
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• 2006

최근 14년간('91-'04) 산림청에 보고된 전국 산불발생 통계자료를 변수로 SPSS Ver 13.0 프로그램을 이용하여 연도별, 월별, 시간대별, 요일별, 지역별, 피해 수종별, 원인별, 피해면적별, 진화 소요시간별 빈도분석을 실시하였다. 그 결과 연도별 산불발생건수는 2001년도에 가장 많았고, 월별로는 매년 4월에, 시간대 별로는 $14{\sim}15$시 사이에, 요일별로는 일요일에, 지역별로는 경북 > 강원 > 전남 > 경기 순으로, 피해 수종별로는 소나무림에서 가장 많이 발생하였다. 또한 원인별로는 입산자실화와 논 밭두렁소각 등이 주요 원인이지만 최근에는 방화에 의한 산불발생이 증가하는 경향이었다. 피해면적별로는 5 ha 미만의 소형 산불이 93.7%로 가장 많이 발생하는 경향이었고, 30 ha 이상의 대형 산불은 강원도 지역이 44.2%로서 가장 많이 발생하였다. 진화소요 시간별로는 30 ha 이상의 대형 산불(1,113분)이 5 ha 미만의 소형 산불(148분)보다 7.5배 더 소요되는 것으로 나타났다. 특히 대형 산불에 의한 피해면적은 건당 평균 470 ha로 나타났다.

• 한국안전학회지
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• 제33권3호
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• pp.15-20
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• 2018

There have been a number of major fatal fire accidents in Korea recently. The number of fires in 2017 were 44,178, which is not only increasing number of fires but also increasing in casualties. Particularly, the fire at Jecheon Sports Center, which suffered many casualties, is expected to have a huge impact. The cause of the fire has not been determined yet, but heat waves on the ceiling have also been pointed out. As such, the copper heating waves, which are used as a preventive measure against damage of pipes due to freezing of pipes, etc., always have a fire hazard. To determine the possibility of a flame-resistant heated fire, a positive electric cable product was used to artificially ignite and analyze the results. In case of a short circuit, the external covering of the positive electric cable is damaged, but not short circuit unless the heating material surrounding the wire is damaged. Due to the characteristics of heating cable for preventing copper waves, the chances of insulation becoming more severe due to moisture and temperature changes are higher than normal wires. If the internal heating system is carbonized by insulating deterioration without damage to the outer coating, it is likely to cause trekking, to form a winding loop in the heating materials, and to cause short circuit in the heated materials. For the positive temperature line, if the middle is shorted, the current continues to flow to the short circuit unless the breaker disconnects. Consequently, a heated fire that does not cut off the power immediately may leave multiple marks or cuts.

• 한국치위생학회지
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• 제11권1호
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• pp.127-136
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• 2011

Objectives : The writer aimed to examine the dynamic aspect on damage and to be conducive to the swift cure according to right treatment to educate prevention of injury through surveying on the number of the damaged teeth given injury, tooth kind, type in damage, place and cause for being damaged, frequency by month and by time level, and location of the damaged tooth. Methods : Targeting 343 teeth of receiving injury in 201 patients who visited the department of pediatric dentistry, the department of preservation, and the oral and maxillofacial surgery in a dental hospital in Cheonan city from April 2007 to April 2009, by having the dental injury as the main reason, the following conclusions were obtained. Results : 1. Deciduous teeth were indicated to be the highest in imperfect luxation with 60.7%, and were indicated to be in order of crown fracture with 25.5%, root fracture with 12.4%, and perfect luxation with 1.4%. The permanent teeth were indicated to be the highest in crown with 58.1%, and were indicated to be in order of imperfect luxation with 27.3%, root fracture with 13.1%, and perfect luxation with 1.5%(p<0.001). 2. In case of deciduous teeth for a place with damage, the home was indicated to be the highest with 31.7%. The permanent teeth were indicated to be the highest(p<0.001) in the road and stairs with 40.4%. As to a cause for damage, both deciduous and permanent teeth were indicated to be the highest(p<0.001) in a cause for falling with 53.1% and 30.8%, respectively. 3. As for a treatment method, in case of deciduous teeth, the close observation was indicated to be the highest with 46.9%. In permanent teeth, the resin restoration was indicated to be the highest(p<0.001) with 22.2%. Dental injuries in deciduous teeth and permanent teeth are showing diverse aspects. Conclusions : It is important to arrange guidelines on cure of the damaged teeth by injury through continuing a dynamic research on these aspects. Also, the damage in deciduous teeth may have direct and indirect influence upon growth in successional permanent teeth. Thus, through careful treatment, the injury needs to be minimized. It is considered to be likely necessary for a right coping method when injury occurs, and above all, for enough prior education so that injury cannot occur.

• 한국압력기기공학회 논문집
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• 제5권2호
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• pp.20-26
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• 2009

The dominant incidents category for onshore and offshore natural gas transmission pipelines in the world is associated with outside forces. Incidents in the outside forces category embrace acts of nature, which typically cause widespread structural damage, as well as act of man, whose effects tend to cause dents and/or gouges localized at point of contact that are referred to as mechanical damage. Therefore, these damage types must be better addressed to avoid unnecessary and costly repairs and the possibility of catastrophic events. First of all, the characterizing features of mechanical damage in gas pipelines were evaluated by using of excavator or boring machine. There is no reliable method for evaluating the safe operating pressure of pipeline affected by mechanical damage. It is especially important to evaluate the remaining strength of damaged pipelines due to outside force. Therefore, the full scale burst tests were conducted to evaluate the remaining strength of pipe with mechanical damage that combines a dent and a gouge. This paper is supposed to provide information that will assist in developing a criterion to assess serviceability in pipelines with mechanical damage.