The Influence of AH-26 and Zinc Oxide-Eugenol Root Canal Sealer on the Shear Bond Strength of Composite Resin to Dentin

Cho, Ju-Yeon,Jin, Myoung-Uk,Kim, Young-Kyung,Kim, Sung Kyo 大韓齒科保存學會 2006 Restorative Dentistry & Endodontics Vol.31 No.3

AH-26 근관실러가 상아질에 대한 복합레진의 전단결합강도에 미치는 영향을 평가하기 위하여 144개의 발거된 대구치를 실린더형의 몰드에 매식한 다음 치관부의 상아질 표면을 노출시킨 후 편평하게 연마하고 AH-26을 도포한 군, ZOE paste를 도포한 군 및 실러를 도포하지 않은 대조군으로 나누어 One-step 상아질 접착제를 처리한 후에 Charisma (Heraeus Kulzer, Germany) 복합레진을 적용하고 광중합시켰다. 시편을 분리하여 37℃ 항온조에 24시간 보관후 Instron test machine (Model 4202, Instron Corp., USA)을 이용하여 시편의 전단 결합 강도를 측정하고 one-way ANOVA 및 Tukey's studentized rank test로 통계 분석하였다. AH-26 근관실러로 처리한 군과 대조군은 ZOE 근관실러 처리군에 비해 유의하게 놓은 접착강도를 나타내었다 (p<0.05). AH-26 근관실러 처리군과 아무 처리하지 않은 대조군 사이에는 결합강도에 있어 유의한 차이를 나타내지 않았다 (p>0.05). 본 연구의 조건에서는 ZOE 근관실러는 상아질에 대한 복합레진의 전단결합강도를 저하시키는 반면 AH-26 근관실러는 유의한 영향을 미치지는 않는 것으로 보인다. 따라서 임상에서 근관실러로 AH-26을 사용한 근관충전 후에는 즉시 복합레진 코어를 해 주어도 결합력에 저해가 없을 것으로 여겨진다. The purpose of this study was to evaluate the influence of the AH-26 root canal sealer on the shear bond strength of composite resin to dentin. One hundred and forty four (144) extracted, sound human molars were used. After embedding in a cylindrical mold, the occlusal part of the anatomical crown was cut away and trimmed in order to create a flat dentin surface. The teeth were randomly divided into three groups; the AH-26 sealer was applied to the AH-26 group, and zinc-oxide eugenol (ZOE) paste was applied to the ZOE group. The dentin surface of the control group did not receive any sealer. A mount jig was placed against the surface of the teeth and the One-step dentin bonding agent was applied after acid etching. Charisma composite resin was packed into the mold and light cured. After polymerization, the alignment tube and mold were removed and the specimens were placed in distilled water at 37℃ for twenty four hours. The shear bond strength was measured by an Instron testing machine. The data for each group were subjected to one-way ANOVA and Tukey's studentized rank test so as to make comparisons between the groups. The AH-26 group and the control group showed significantly higher shear bond strength than the ZOE group (p<0.05). There were no significant differences between the AH-26 group and the control one (p>0.05). Under the conditions of this study, the AH-26 root canal sealer did not seem to affect the shear bond strength of the composite resin to dentin while the ZOE sealer did. Therefore, there may be no decrease in bond strength when the composite resin core is built up immediately after a canal filling with AH-26 as a root canal sealer.

Metal stain on monolithic zirconia restoration: A case report

Min-Sang Cha,Sang-Woon Lee,Yoon-Hyuk Huh2,Lee-Ra Cho2,Chan-Jin Park 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.2

In restorative treatment using fixed dental prostheses, dentists should select appropriate restoration material among various types of dental materials. The strength, marginal fit, esthetics, wear resistance, biocompatibility, and cost are important factors in the choice of restoration materials. The present case showed a surface stain on a monolithic zirconia restoration that was due to wear between the monolithic zirconia restoration and the base metal alloy restoration. This phenomenon was confirmed by surface roughness measurement and electron probe micro-analysis.

시뮬레이션을 이용한 역사적 전투사례의 승패요인 분석

조성진(Sung-jin Cho) 한국경영과학회 2010 經營 科學 Vol.27 No.1

Purpose of the War history's study is getting instruction by analyzing victory and defeat factor. This study is studied by qualitative form in war study mainly. In case recording literature is full, victory and defeat factor analysis is easy, but occasionally definite analysis that recording literature is feeble is difficult. Also, when it is battle result that escape common sense, about victory and defeat factor, various estimations are brought. As such example, there is Myeong-Ryang sea-battle at Japanese Invasion of Korea in 1592 and Korea(Cho-Sun) naval forces did big victory in 13 vs. 133 numerical inferiorities. This study presented method of study that using agent based simulation model for quantitative analysis of these victory and defeat factor.

시뮬레이션을 이용한 역사적 전투사례의 승패요인 분석

조성진(Cho Sung-jin) 한국경영과학회 2009 한국경영과학회 학술대회논문집 Vol.2009 No.10

War history’s study purpose is getting instruction by analyzing victory and defeat factor. This study is studied by qualitative form in war study mainly. In case recording literature is full, victory and defeat factor analysis is easy, but occasion definite analysis that recording literature is feeble is difficult. Also, when it is battle result that escape common sense, about victory and defeat factor, various estimations are brought. As such example, there is Myeong-Ryang sea-battle at Japanese Invasion of Korea in 1592 and Korea(Cho-Sun) naval forces did big victory in 13 vs. 133 numerical inferiorities. This study presented method of study that using agent based simulation model for quantitative analysis of these victory and defeat factor.

The Evolving Policy Debate on Border Closure in Korea

Su-Jin Kang,Jihyun Moon,Heewon Kang,Heekyoung Nam,Sangwoo Tak,Sung-Il Cho 대한예방의학회 2020 Journal of Preventive Medicine and Public Health Vol.53 No.5

302 Copyright © 2020 The Korean Society for Preventive Medicine J Prev Med Public Health 2020;53:302-306 • https://doi.org/10.3961/jpmph.20.213 The Evolving Policy Debate on Border Closure in Korea SuJin Kang1, Jihyun Moon2, Heewon Kang1, Heekyoung Nam3, Sangwoo Tak1, Sung-il Cho1,3 1Institute of Health and Environment, Seoul National University, Seoul, Korea; 2Samsung Advanced Institute of Health Science and Technology, Sungkyunkwan University, Seoul, Korea; 3Department of Public Health Sciences, Graduate School of Public Health, Seoul National University, Seoul, Korea Brief Report Objectives: In this paper, we aimed to investigate the evolving debate over border closure in Korea during the coronavirus disease 2019 (COVID-19) pandemic, to address the main themes associated with border closure, and to discuss the factors that need to be considered when making such decisions. Methods: We collated and reviewed previously conducted review studies on border closures during infectious disease outbreaks to derive relevant themes and factors. Results: According to our systematic review on border closures and travel restrictions, the effects of such containment efforts are limited. We suggest considering the following factors when determining whether to impose border closure measures: (1) disease characteristics, (2) timeliness of implementation, (3) transmission delay and the basic reproduction number, (4) globalization and pandemics, and (5) social and economic costs. Conclusions: Our assessment indicates that the effects of border closures are at best temporary and limited. Alternative measures must be contemplated and implemented to suppress the spread of COVID-19 in particular and infectious diseases more broadly.

재무분석가의 낙관주의가 walkdown에 미치는 영향과 예측어려움의 조절효과

곽상진(Kwak, Sang-Jin),조용언(Cho, Yong-Eon),하순금(Ha, Soon-Gum) 한국경영교육학회 2020 경영교육연구 Vol.35 No.5

[연구목적] 본 연구는 재무분석가의 낙관주의 동기 유인이 예측 walkdown에 미치는 영향을 인지심리적 측면에서 검증하고 예측어려움이 높을수록 재무분석가의 낙관주의 동기유인이 예측 walkdown을 보다 강화하는지를 분석하였다. [연구방법] 이를 위해 재무분석가의 낙관주의 동기 유인과 예측어려움과 관련된 국내외 선행연구에 관한 문헌을 바탕으로 실증분석에 필요한 가설을 설정하였다. 가설 검증에 사용된 표본은 2011년부터 2016년까지 유가증권 시장의 상장기업 중 820개의 기업-연도표본이다. 재무분석가 이익예측자료와 재무자료는 Kis-Value에서 수집하였다. 수집된 자료를 바탕으로 Bradshaw et al.(2016)가 제시한 연구모형에 대한 회귀분석을 실시하였다. [연구결과] 본 연구의 분석결과는 첫째, 재무분석가의 낙관주의 동기 유인이 클수록 예측walkdown이 커지는 것으로 나타났다. 둘째, 예측어려움이 높을수록 재무분석가의 낙관주의 동기 유인이 예측walkdown을 강화하는 것으로 나타났다. 이는 재무분석가의 지향성 있는 결론에 대한 낙관주의 동기 유인이 클수록 매출액과 영업이익의 walkdown이 커지며, 이 과정에서 예측어려움이 조절작용을 하고 있음을 의미한다. [연구의 시사점] 본 연구는 낙관적 예측 편의가 존재하는 재무분석가의 보고서를 이용하는 시장참여자들이 합리적 판단을 할 수 있는 근거를 제공하고 재무분석가의 낙관적 예측편의에서 파생되는 시장의 부정적인 영향을 사전에 차단할 수 있는 정책수립의 근거를 제공하는데 시사점을 준다. [Purpose] This study examines the pattern of analysts’ forecasts within a fiscal year, which begins with optimism and declines as the earnings announcement date approaches, and also does that one factors, forecasting difficulty, interact with analysts’ incentives for optimism to induce cross-sectional variation in the steepness of forecast walkdown. [Methodology] As follows are univariate t-test and multivariate regressions results from a sample of 820 firm-years listed in Korea Exchange between 2011 and 2016. [Findings] The general association between analysts’ incentives for optimism and forecast walkdown is supported by empirical evidence. In addition, it is supported that as difficulty is higher, forecast walkdown becomes steeper. [Implications] This result means that analysts begin with optimism to react to motivation for a directional conclusion at the beginning of the year, adjust downward their forecast to react to motivation for accuracy as the earnings announcement date approaches. In addition, this means forecasting difficulty is in the highest at longer forecast horizons, it declines with the release of information during the year. Then, based on Kunda’s(1990) work, the biased accessing of information to support optimistic forecasts declines, leading to a forecast walkdown.

연구보문 : 식물환경 ; 폐가축사체의 농업적 재활용을 위한 가축사체 액상부산물의 액비화 조건 구명

서영진 ( Young Jin Seo ),서동철 ( Dong Cheol Seo ),강세원 ( Se Won Kang ),이상규 ( Sang Gyu Lee ),박주왕 ( Ju Wang Park ),최익원 ( Ik Won Choi ),성환후 ( Hwan Hoo Sung ),강석진 ( Seog Jin Kang ),조주식 ( Ju Sik Cho1 ) 한국환경농학회 2013 한국환경농학회지 Vol.32 No.4

가축사체 액상부산물을 이용하여 액비의 최적조건(미생물, pH, 미생물 주입량)을 조사하였고, 이들 최적 조건하에서 112일간 부숙하여 액비의 품질을 평가하였다. 가축사체 액상 부산물 액비 부숙시 최적 LP 미생물의 주입량은 0.5 mL/100mL이었으며, pH는 7 조건에서 각각 50점으로 완숙판정을 받았다. 최적조건하에서 112일 동안 부숙시킨 액비의 부숙도 는 부숙 후 28일에 50점을 받아 완숙판정을 받았으며, 부숙기 간이 길어짐에 따라 부숙 56일에는 온도가 60℃를 넘어 최고 점인 55점을 받았고, 이후 온도가 조금씩 낮아져 부숙 후 112 일에는 실온조건에 이르렀다. 완숙된 가축사체 액상부산물 액 비의 품질을 평가해본 결과, 최적조건하에서 부숙시킨 액비의 경우에는 T-N, P2O5 및 K2O의 함량이 28일에 가장 높았으며, 시간이 경과함에 따라 약간 감소하는 경향이었다. 또한, 유해성분(As, Cd, Cu, Cr, Hg, Ni, Pb 및 Zn)의 함량은 28일, 56일 및 112일 부숙시킨 액비에서 모두 비료공정규격 기 준치에 적합하였다. 이상의 결과를 미루어 볼 때 가축사체 액상부산물을 농업적 재활용을 위한 액비화 조건은 pH 7조건 에서 LP 미생물을 0.5 mL/100 mL 주입한 경우이다. 하지 만 본 연구에서 비교된 가축분뇨 발효액은 공시재료(가축사체)가 상이하여 향후 가축사체를 이용한 액비의 부숙도 기준이 개선되어야 할 것으로 판단된다. BACKGROUND: Globally, concern about emerging infectious diseases of livestock is growing. For the disposal of the animal carcass, it is necessary to recycle the carcass into an agriculturally usable product. The objective of this study was to investigate the composting conditions of liquid by-product obtained from degradation of animal carcass. METHODS AND RESULTS: Optimum conditions of liquid fertilizer were investigated using different microorganisms, pHs, and volumes of microorganisms (Lactobacillus rhamnosus + Pichia deserticola). Based on the results from the optimum conditions, compost maturity and quality of liquid fertilizer were evaluated for 112 days. The compost maturity of liquid fertilizer were higher in the order of LP(Lactobacillus rhamnosus + Pichia deserticola) > BC(Bacillus cereus) > BS (Bacillus subtilis). The optimum condition under different volumes of LP was injection of 0.5 mL/100 mL. The compost maturity under different pHs were higher in the order of pH 7 > 5 ≥ 9 ÷ 11. The liquid by-product at 56 days after composting was completely decomposed. The concentrations of T-N, T-P and K2O in liquid fertilizer at 56 days were 0.94, 0.17 and 3.78%, respectively, and the sum of those concentrations was 4.89%. CONCLUSION(S): Liquid fertilizer of by-product using pig carcass was decomposed with optimum conditions(LP, pH 7, injection of 0.5 mL/100 mL) in 56 days after composting, and was suitable for official standard of commercial fertilizer.

설화그림카드를 활용한 자기성장 집단 문학치료 프로그램 사례연구 : <해와 달>그림카드를 중심으로

배진형(Bae, Jin Hyoung),조은상(Cho, Eun Sang) 한국독서치료학회 2020 독서치료연구 Vol.12 No.2

이 연구에서는 자기성장을 원하는 참여자들이 설화 <해와 달이 된 오누이>와 <해와 달이 된 오누이>설화 그림카드를 활용한 ‘다시쓰기’ 활동을 하고, 이를 집단 문학치료프로그램에서 나누는 과정을 통해 ‘부모로부터의 심리적 독립’을 탐색해볼 수 있도록 하였다. 설화 선정은 참여자들이 <해와 달이 된 오누이>에 대해 ‘부모로부터의 심리적 독립’의 이야기로 읽고 반응한다는 기존 연구를 근거로 이루어졌다. 연구 결과는 다음과 같다. 첫째, 연구 참여자 대부분은 자신이 부모에게 바라는 욕구에 대해 알아차릴 수 있었다. 둘째, 참여자들은 부모와의 관계를 탐색하거나 재조정해보는 통찰을 얻을 수 있었다. 셋째, 설화뿐 아니라, 제시된 설화 그림카드는 참여자들이 정서적 갈등을 투사하고 촉진하도록 도울 수 있었다. 넷째, ‘다시쓰기’ 전과 후, 설화 그림카드 작업들은 참여자들이 이야기의 방향과 줄거리, 주인공을 선정하는 데에도 효과적인 역할을 하였다. 문학치료에서 이야기를 재구성하는 과정이 자신의 내면을 탐색하는 데 있어 효과적이라는 것은 조은상의 이전 논문에서 검증된 결과이나, 설화 그림카드를 개발하여 활용하는 것은 아직 연구 중에 있다. 추후 지속적인 연구를 통해 설화 그림카드의 유용성과 효과성에 대한 검증이 이루어져야 하겠지만, 이 연구를 통해 설화 그림카드를 설화와 함께 사용하는 것이 참여자들이 내면에 있는 갈등을 투사하는 데에 효과적이고, 보다 명확히 자신의 내면을 표현할 수 있도록 도움을 주었음이 밝혀졌다는 점이 이 연구의 의의라 하겠다. In this study, participants wanting to mature, engaged in ‘re-writing’ activities using a folktale “The Brother and Sister Who Became the Sun and the Moon” and folktale picture cards <The Brother and Sister Who Became the Sun and the Moon>, and explored their psychological independence from their parents through sharing their stories in a group setting. This specific folktale was selected based on existing research where participants read and responded to “The Brother and Sister Who Became the Sun and the Moon” as a story of psychological independence from parents. The results of the study are as follows. Firstly, most of the participants in the study were able to recognize what they need from their parents. Secondly, participants were able to gain insights necessary for exploring or readjusting the relationship with their parents. Thirdly, the suggested folktale picture cards along with the folktale were useful for the participants to project and examine their emotional conflicts. Lastly, before and after re-writing activities, the folktale picture card work played an effective role in participants choosing the direction, plot, and protagonists of their stories. Even though the effectiveness of reconstructing stories in literary therapy to explore one’s inner self has been researched in previous studies, such as Cho Eun Sang’s papers, the topic of developing and utilizing folktale picture cards is still being explored. This study examined the ways in which using folktale picture cards in a literary therapy group helped participants project their inner conflicts and express themselves more clearly and effectively. This study also suggests that future studies will verify the usefulness and effectiveness of folktale picture cards.

최적의 상호상관관계를 갖는 이진 수열의 설계

최언숙,조성진,Choi, Un-Sook,Cho, Sung-Jin 한국전자통신학회 2011 한국전자통신학회 논문지 Vol.6 No.4

Balanced binary sequences of period $2^n-1(n{\geq}1)$ having the two-valued autocorrelation function have many applications in spread-spectrum communications system. In this paper we propose new nonlinear binary sequences which are constructed from Legendre sequences with the same cross-correlation as the sequences proposed by Cho. These sequences include the m-sequences, GMW sequences, Kasami sequences and No sequences which are described in terms of the trace function over a finite field. Also the proposed sequences have more low cross-correlation distribution than the quadratic form sequences proposed by Klapper. 적당한 정수 $n({\geq}1)$에 대하여 2-valued 자기상관관계를 갖는 주기가 $2^n-1$인 균형 이진 수열(balanced binary sequences)은 대역확산 통신 시스템(spread-spectrum communication system)에서 많이 응용되고 있다. 본 논문에서는 르장드르 수열에 의해 구성되는 새로운 3-valued 비선형 이진 수열을 제안한다. 이 수열은 유한체 위에서 트레이스를 이용해 생성하는 가장 우수한 수열인 m-수열, GMW 수열, Kasami 수열, No 수열을 모두 포함한다. 제안된 수열은 Klapper에 의해 제안된 이차형식 수열보다 더 낮은 상호상관관계를 갖는다.

Original Articles : Clinical significance of occult hepatitis B virus infection in chronic hepatitis C patients

( Jae Young Jang ),( Soung Won Jeong ),( Sung Ran Cheon1 ),( Sae Hwan Lee1 ),( Sang Gyune Kim ),( Young Koog Cheon ),( Young Seok Kim1 ),( Young Deok Cho1 ),( Hong Soo Kim ),( So Young Jin ),( Yun Soo 대한간학회 2011 Clinical and Molecular Hepatology(대한간학회지) Vol.17 No.3

Background/Aims: We investigated the frequency of occult hepatitis B virus (HBV) infection in anti-hepatitis C virus (HCV)-positive individuals and the effects of occult HBV infection on the severity of liver disease. Methods: Seventy-one hepatitis B virus surface-antigen (HBsAg)-negative patients were divided according to their HBV serological status into groups A (anti-HBc positive, anti-HBs negative; n=18), B (anti-HBc positive, anti-HBs positive; n=34), and C (anti-HBc negative, anti-HBs positive/negative; n=19), and by anti-HCV positivity (anti-HCV positive; n=32 vs. anti-HCV negative; n=39). Liver biopsy samples were taken, and HBV DNA was quantified by real-time PCR. Results: Intrahepatic HBV DNA was detected in 32.4% (23/71) of the entire cohort, and HBV DNA levels were invariably low in the different groups. Occult HBV infection was detected more frequently in the anti-HBc-positive patients. Intrahepatic HBV DNA was detected in 28.1% (9/32) of the anti-HCV-positive and 35.9% (14/39) of the anti-HCV-negative subjects. The HCV genotype did not affect the detection rate of intrahepatic HBV DNA. In anti-HCV-positive cases, occult HBV infection did not affect liver disease severity. Conclusions: Low levels of intrahepatic HBV DNA were detected frequently in both HBsAg-negative and anti-HCV-positive cases. However, the frequency of occult HBV infection was not affected by the presence of hepatitis C, and occult HBV infection did not have a significant effect on the disease severity of hepatitis C. (Korean J Hepatol 2011;17:206-212)