Effect of two different calcium hydroxide paste removal techniques on apical leakage : an electrochemical study

Park, Chan-Je,Jeon, Kyung-A,Kwon, Ho-Beom 大韓齒科保存學會 2006 Restorative Dentistry & Endodontics Vol.31 No.3

본 연구의 목적은 근관내 약제로 사용되는 수산화칼슘의 제거방법이 근관충전 후 치근단 미세누출에 미치는 영향을 알아보기 위함이다. 70개의 발거된 단근치를 엔진구동형 ProFile로 근관형성한 후 수용성 수산화칼슘 제제를 1주일간 적용하고 두 군으로 나누어 각기 다른 방법으로 제거하였다. A군은 NaOCI로 근관세정만을 시행하였으며, B군은 근관형성 시 사용된 file보다 한 단계 큰 크기의 ProFile을 사용하여 근관을 재형성한 후 NaOCI로 세척하였다. 근관충전 후 전기화학적 방법으로 24일 동안 치근단 누출을 측정, 비교하였다. 본 연구의 결과 수산화 칼슘 제거를 위한 두가지 방법은 근관충전후 치근단 미세누출에 있어서 차이가 없음을 알 수 있었다. This study evaluated the effect of two different calcium hydroxide (Ca(OH)_(2)) paste removal techniques on the apical leakage of canals obturated with gutta percha cones and sealer after removing a Ca(OH)_(2) dressing using an electrochemical method. Seventy extracted single-rooted teeth were instrumented on with Profile rotary files under NaOCI irrigation. Fifty-eight canals were filled with calcium hydroxide paste, which was then removed using one of the following two techniques. In group A, calcium hydroxide was removed using only NaOCI irrigation, and in group B, the canals were re-prepared with a Profile rotary files-one size larger than the previous instrument and were irrigated with NaOCI. In both groups, the root surfaces were coated twice with nail varnish from CEJ to an area 4㎜ away from the apex after canal obturation. Apical leakage was measured using an electrochemical method for 24 days. All the specimens showed leakddffqage that increased markedly in the first three days. There was no significant difference between the two groups (p > 0.05). The effect of two calcium hydroxide paste removal techniques on the apical leakage was not different during a short period.

경주지역 여고생의 초경과 체성장간의 관계

김준섭,권오구,박진석,오종수,박정현,박제식,안세한,이용환,서정호,신태섭,최영배,김덕수,이관,박수경 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

본 연구는 경주지역 1개 고등학교 3학년 여고생을 대상으로 초경 시작 전인 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레 수치와 초경 연령을 파악하여 여성의 초경이 빠를수록 체성장 속도의 변화가 있을 것이라는 가설을 기초로 두 요인간의 관련성을 파악하고자 시행되었다. 경주시 1개 여자고등학교 3학년생 총 317명에 대해 ㅊ경 나이, 초경시 심리 상태, 초경이 시작되었을 때의 상담 여부와 상담하였던 사람, 부모 신장과 초경전후의 식사 규칙성, 다이어트 경험, 수면시간, 스트레스, 음주/흡연 여부, 질병력 등에 대한 설문 조사를 시행하였고, 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레에 대한 정보는 건강기록부에서 확보하였다. 상기 대상자 중 건강기록부가 분실된 39명, 초경나이에 대해 응답하지 않았던 29명 및 결석 등으로 조사를 하지 못하였던 42명을 제외한 조사 대상자는 206명으로 선정하였다. 대상자들의 초경연령 평균값(Mean±SD)은 13.0±1.11이었고, 초등학교 4학년부터 고등학교 2학년까지의 초경 이후 신장 성장률은 감소하였으며, 초경연령이 빠른 군이 초등학교 때는 신장에 있어서 우위를 차지하나 고등학교에 오면서 신장은 비슷한 수준이 되었다. 초경후 1-2년 사이에 체중과 흉위의 증가율은 감소하였고, 초경연령이 빠른 군이 초등학교와 고등학교 사이에 체중과 흉위에서 모두 우위를 차지하였다. 본 연구의 결과는, 흔히 이차 성징의 시작 시점 혹은 사춘기의 시작 시점으로 보고있는 초경 연령이 청소년기의 성장과 밀접한 관련성이 있고, 특히 체중과 흉위의 성장 속도와 밀접한 관련성이 있음을 시사한다. To understand the onset of menarche in relation to changes in physical growth that take place during female adolescence, especially the changes in height and weight velocity. The 207 senior in one women high school of Kyongju were investigated in April 3 to 8, 2001. We collected the information, relation in the age at menarche, height & weight of parents, regularity of eating, and obesity diet, duration of sleeping, sickness & stress near age at menarche, by self-recording. The status of height, weight & chest circumference between the 4th grade of primary school and the junior of high school was collected by individual Health Record. The results were followed; The average age at menarche was 12.95±1.11 years old and the most frequent age of menarche is 13 years. After menarche, the velocity of height, weight and chest circumference were decreased. The most rapid group of menarche hold dominant position in height during elementary school. As time passed, they dont hold dominant position in height. The most rapid group of menarche get an advantage in the weight and the girth of chest after elementary school. The height of subjects is directly proportional to the height of their parents. These results suggest that the starting age at menestuation can be closely associated with physical growth and development.

식품 기준·규격의 합리적 관리 ·운영에 관한 연구(Ⅰ) : 두부,식용유지, 전분의 분말상 원료에 관하여 Powdered marerials of Tofu, Edible oil, Starch

김희연,홍진환,박혜경,한상배,박종석,이은주,이정성,송경희,최은희,최영준,소경아,성영제,이주엽 식품의약품안전청 2000 식품의약품안전청 연보 Vol.4 No.-

본 연구는 분말상 원료(전분, 대두분)의 저장유통시 품질변화를 건전성과 안전성 측면에서 검토하여 식품의 기준 ·규격 설정f.」 합지적으로 반영하고자 하였다. 전분과 패두분의 이물을 검사하고, 2종 대두분(중국산, 미국산)을 ?0일간 IS'c와 30t에 저장하면서 성상, 수분, 산가, 과산화물가, 지방산 조성,아플라톡신 BB의 생성여부를 분석하였다. 중국산 대두분 30'』 저장군에서 50일 이후 곰팡이가 발생한 것 이외에 모든 시료에서 양호한 성상을 나타내었고, 전분과 대두닥 모든 시료에서 이물은 검출되지 않았다. 산가는 중국산과 미국산 시료간에 편차를 보여 증국산 30"C, 50일 저장시료에서 약 10배끙도 증가하였고, 과산화물가는 저장 90일후 15'E 저장군은 약 2.3배, 30'c 저장군은 3배정도 증가하였다. 대두분의 주요 지방산은 linoleic acidf18. 2), oleic acid(18 : 1), palmitic acid(16 : 0)이었으며, 3개월 저장에 따른 지방산 함량의 변화는 미미하였다. 아플라톡신 B₁은 모든 시료에서 검출되지 않았다. The objective of this study was to investigate auality changes of type raw materials(starch, soy flour) during various storage conditions. Starchflour(source of China, U.S.A) were slfred under two temperature(15'C, 30'c) forSensory evaluation, (o.reign material test, moisture content, acid value, peroxide ualue,composition, aflatorin Bi were analyzed. China soy flour(stor·ed 30'f) was contaminated by fungj on 50 days. Except for soy flour contardnated by fungi, sensory characteristics were not changed and foreign mater;als were notdetected. Acid value of China soy flour(stored at 30'C, 90 days) was about 10 times higherlevel before storage and acid value was more influenced by source(China, USA). Peroxide valuewas in proportion with the storage period slightly. The major fatty acid of soy flour waslinoleic acid(18 . 2), an(3 the change of fatty acid composition was not observed. Aflatoxlrl Blwas not detected.

Protective Effects of N-acetylcystenine and Selenium against Doxorubicin Toxicity in Rats

Yeo-sung Yoon,Sun-don Kim,Min-hye Lee,Heung-shik S.Lee,In-se Lee,Je-kyung Sung,Eun-sung Park 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Effects of N-acetylcysteine and Selenium against Doxorubicin Toxicity in RatsEun-sung Park, Sun-don Kim1, Min-hye Lee, Heung-shik S. Lee, In-se Lee, Je-kyung Sung and Yeo-sung Yoon*

국민학교 아동의 체력실태 : 형태와 운동능력 중심으로 Based on Physique and Motor Fitness

朴庄平,李光宰,盧成圭,洪寬伊,李京濟 江原大學校附設體力硏究所 1980 江原大學校附設體育科學硏究所論文集 Vol.- No.5

시멘트 콘크리트의 건조수축균열 특성

박제선,윤경구,이주형,김태환,정원경 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

콘크리트는 본질적으로 인장강고와 휨강도가 약하며 취성적 성질을 나타내는 결점을 가지고 있으므로 이를 보강할 목적으로 콘크리트에 섬유를 혼입한 섬유보강 콘크리트가 크게 각광받고 있다. 특히 폴리프로필렌 섬유보강은 모르타르 및 콘크리트가 건조나 동해에 의해 수축될 때 구속에 의해 발생되는 인장응력 및 균열을 제어하고 인성의 증가와 충격, 마모, 피로에 대한 저항성, 내구성을 증대시키는 장점을 가지는 것으로 보고 되고 있다. 1축으로 구속된 건조수축의 구속으로 인한 조강형 콘크리트의 잔류응력을 선형모델을 이용하여 예측할 수 있었고 조강형 콘크리트에 섬유보강으로 인한 건조수축 제어효과는 일반큰코리트에 비해 효과가 매우 큰 것으로 나타났다. 따라서 폴리크로필렌 섬유의 혼입으로 인해 콘크리트의 균열제어가 가능하며, 균열 폭이 큰 균열보다는 많은 미세 균열을 유도하는 것을 알 수 있었다. 섬유보강 조강형 큰크리트의 동결융해저항특성은 거의 동해의 손상을 받지 않으며 좋은 내구성을 유지하고 있는 것으로 나타났다. 이는 불규칙하게 배향된 섬유가 공극수의 이동을 효과적으로 제어함으로써 메트릭스 내의 팽창압으로 인한 파괴를 최대한 줄였기 때문이라고 보여진다. 표면손상과 박리저항에 매우 우수하며 저항성을 증진시키는 효과가 뛰어남을 확인할 수 있었다. 따라서, 내구적 측면의 유지, 보수에 있어서도 섬유보강은 그 효과가 큰 것으로 나타났다. To improve the brittle nature of concrete, discrete fibers can be adapted in concrete. Since polypropylene fiber has many advantages in many points on its chemical stability and good durability, its usages have been increased gradually. It has been reported than polypropylene fibers can not only control restrained tensional stresses and cracks, but also increase toughness, resistance to impact, corrosion, fatigue, and durability. Although the polypropylene fiber reinforced concretes with ordinary cement have been studied so much, those with very early strength concretes have not studied at all. Therefore, it is necessary to initiate and conduct the researches for the polypropylene fiber reinforced very early strength concretes which has enough workability and durability. This study of polypropylene fiber reinforced very early strength concrete focused on the investigation each material's effect into strength development with analysis of restrained shrinkage properties with one-dimensional concrete members. The results showed that more optimized mixture combinations could be selected in very early strength concrete by incorporating polypropylene fibers, keeping in same strength levels at urgent repair works. The formation of needle-shape ettringite helps the early strength development, specially at flexural and this enables the repaired concrete structures or pavements to be opened to traffic after 3 hours of concrete placement. A residual stress of early strength concrete caused by one-dimensional restrained drying shrinkage was predicted from linear model. the control of shrinkage crack by fiber reinforcement at early strength concrete was better than that of ordinary portland cement concrete because of bridging effect of fiber at early age and resulting of more hair cracks rather than fewer wider cracks. As a results, this dissertation clearly validated the fiber reinforcement on the strength development and durability of polypropylene fiber reinforced very early strength concrete, and characteristic of restrained shrinkage. The proposed optimized concrete mixtures might be satisfactory applied at the repair works in fields, because of its durability and crack control capacity against freeze-thaw and contraction at early age, respectively.

양생온도변화에 따른 콘크리트의 강도 예측

박제선,김태경,이주형,윤청호 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

The maturity concept was adopted to predict the strength of concrete, which was subjected to several temperature levels and variable curing conditions. Penetration test and compressive test were conducted to measure the initial and final setting time and the compressible strength of concrete specimen, respectively. Also, the temperature and time were measured at some time intervals for calculating the maturity. The initial and final setting were delayed as the w/c ration increased and curing temperature decreased. The relationships at the relative strength and the equivalent age were proposed at different w/c ratio for the several temperature curing conditions, and these were applied for the variable curing conditions.

액상 실리카륨을 혼입한 콘크리트의 파괴특성

박제선,민창동,김태경,이주형 江原大學校 産業技術硏究所 1995 産業技術硏究 Vol.15 No.-

The experimental study is conducted to analyze the characteristics of concrete included silica fume. The workability of concrete is controled by the ratio of mixture, such as superplastcizer, based on the constant rates of sand and cement. It is concluded that the strength and the frectu Toughness of concrete with silica fume are very improved.

폐주물사를 혼입한 콘크리트의 최적배합설계를 위한 기초적 연구

박제선,김태경 江原大學校 産業技術硏究所 1996 産業技術硏究 Vol.16 No.-

The waste foundry sand might be recycled in concrete, resulting in energy saving and enviromental protection. An half Factorial Experiments were performed with the variables of W/C ratio, S/A, Sand/Waste foundry sand ratio and Slump as a preliminary study for optimum mis design of concrete. The resutls show that then W/C ratio is the most important factor to the concrete strength. The substitute fo waste foundry sand uo to 305 has little influence, saying that it can substitute the fine aggregate without damaging the concrete properties.

CuO-ZnO-Al₂O₃촉매상에서 메탄올의 수증기개질반응에 관한 연구

박해경,김문찬,김경림,이용제 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.1

The steam reforming of methanol was studied over CuO-ZnO-Al₂O₃catalyst at the range of temperatures between 150℃ and 300℃, the atmospheric pressure, the contact times between 0.04g cat h/mL and 0.1g cat h/mL and mole ratios of water/methanol between 0.67 and 1.5 in a fixed bed continuous flow reactor. The conversion of methanol and the yield of H₂increased with the increase of pH in the precipitate solution and mole ratio of water/methanol. In the precipitate solution of pH 10, as the temperature increases especially above 250℃, the yield of H₂increased but the selectivity of H₂decreased due to side reaction. The activation energy of steam reforming of methanol was found to be 4.44 kcal/mol over CuO-ZnO-Al₂O₃catalyst at the mole ratio of Cu/Zn, 8:1.