바륨 페라이트를 함유한 알지네이트 자성 복합 입자의 제조

이덕연,오영일,김동현,김광만,김경남,이용근 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

Magnetic polymer composite materials with high coercivity have potential applications in medical diagnostic technologies, magnetic drug delivery, and hyperthermic cancer treatment. The purpose of this study was to prepare the magnetic composite particles by encapsulating barium ferrite powders with alginate and to investigate their physical and biological properties. 0.4 g of sodium alginate was dissolved in 20 ml of distilled water and different amount (0.4~4 g) of barium ferrite powder was dispersed in alginate solution using an ultrasonication method. The resulting barium ferrite-alginate slurry was added dropwise to a CaCl2 solution to form magnetic Ca-alginate composite beads. They were separated by filtration and washed several times with water and ethanol. The final product was then completely dried at 40℃ under vacuum to obtain brownish black powders (0.1~1 mm in size) with a high magnetic response when submitted to a small magnet. Average size of magnetic composite particles was dependent on the amount of barium ferrite and the viscosity of slurry . The morphological and dimensional analyses of magnetic composite particles were performed by optical microscopy and scanning electron microscopy. Magnetic polymer composite particle was found to maintain the high coercivity. The saturation magnetization value for magnetic Ca-alginate composites increased with the increase of the barium ferrite/alginate ratio. The amount of self-heating induced by hysteresis under an alternating magnetic field was measured as a function of barium ferrite/alginate ratio in distilled water. According to the results, the encapsulated magnetic composite is expected to be useful for hyperthermia and chemotherapy remarkably.

부가중합형 실리콘 인상재의 표면 친수성이 미세부 재현성에 미치는 영향

오영일,황수영,이덕연,김경남,김광만 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.3

The purpose of this study was to investigate the relationship between surface hydrophilicity and detail reproducibility of die stone for hydrophilic polyvinyl siloxane impression materials modified with nonionic surfactants. Hydrophilic polyvinyl siloxane impression materials were prepared with a polydimethylsiloxane composition and nonionic surfactants. The surfactants used were nonylphenoxy poly(ethyleneoxy) ethanol homologs of varying ethyleneoxy chain length. These homologs are designated NP4, NP6, and NPIO according to the mole number of ethyleneoxy group of 4, 6, and 10, respectively. The contact angle, consistency, and detail reproducibility for hydrophilic polyvinyl siloxane impression materials were tested. The incorporation of nonionic surfactant into polyvinyl siloxanes enhanced their hydrophilicity and consequently led to significant reduction in contact angles. Significant differences in contact angle were found among the samples (P < 0.05). The contact angle was lowest when NP4 was incorporated even though NP4 is less hydrophilic than NP6 and P1O. This implies that the exposed surfactant concentration on the surface was highest when NP4 was used. The consistency of surfactant-modified silicone impression materials were not affected by the type of surfactants used in this study. However, NP4-modified polyvinyl siloxane impression material showed the highest quality reproduction of the thinnest line, indicating highest wettability with gypsum among the samples. In conclusion, the surface concentration of surfactant on the silicone impression material was a crucial factor in determining wettability. The suface hydrophilicity of surfactant-modified silicone impression materials was of major relevance to the detail reproduction of die stone.

Linear Polymerization Shrinkage of Light-Cured Composite Restorative Materials Determined with a Linometer

Lee, Doug-Youn,Lee, Young-Joo,Park, Sung-Ho,Kim, Kyoung-Nam 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.5

Reaction Characteristics of Emulsion Copolymerization of Methyl Methacrylate and Butyl Acrylate with Alkali - Soluble Resin

이동윤(Doug Youn Lee),박영준(Young Joon Park),김중현(Jung Hyun Kim) 한국고분자학회 1995 한국고분자학회 학술대회 연구논문 초록집 Vol.1995 No.4

Fate and Mineralization of Organo-N in Soils Amended with Livestock Manure

Myoung-Youn Lee(이명연),Kyo-Seok Lee(이교석),Dong-Sung Lee(이동성),Jae-Bong Lee(이재봉),Ri-Na Joo(주리나),Doug-Young Chung(정덕영) 한국토양비료학회 2016 한국토양비료학회 학술발표회 초록집 Vol.2016 No.3

기질 및 애착유형이 청소년 시험불안에 미치는 영향

김소연,이영식,한덕현,남규탁,고복자 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.3

목적 시험 불안 원인 파악에 대한 연구의 일환으로 중고등학생을 대상으로 서울시 학교보건원과 연계하여 대규모 설문조사를 통해 개인의 타고난 기질과 어린 시절 형성된 애착유형이 시험불안에 어떤 영항을 미치는지를 파악하고자 본 연구를 시행하였다. 방법 2005년 5월부터 6월까지 서울시내 6개의 중학교와 5개의 인문계 고등학교, 1개의 실업계 고등학생 4,178명을 대상으로 하였다. 시험불안의 측정도구로는 시험불안 목록(Test Anxiety Inventory)을 사용하였고, 애착 형성의 질을 측정하기 위해 애착관계형성 척도-개정판(RAAS : Re-vised Adult Attachment Scale)을 사용하였고, 기질 성격 검사(Junior Temperament Character Inventory, 이하 JTCI)를 사용하여 기질을 측정하였다. 결과 여중생, 남중생, 남고생, 여고생 네 군으로 나누었을 때 시험불안은 여고생이 다른 세 군에 비해 높았다. 애착유형은 네 군간에 의미있는 차이가 없었고, 기질 면에서 여고생이 남고생 보다 사회적 민감성이 큰 반면에 자극 추구요인은 의미있게 낮았다. 중학생의 경우 남녀 간의 차이는 없었다. 시험불안이 높은 군은 낮은 군에 비해 애착유형측면에서 볼 때 불안이 높은 반면 친밀성과 의존성은 낮았으며 기질 면에서는 위험 회피 요인이 높은 반면 인내력이나 사회적 민감성은 낮았다. 네 종류의 기질특성 및 세 종류의 애착유형이 시험불안에 미치는 중요도를 보았을 때 위험 회피 기질 특성이 가장 컸으며 다음으로 불안한 애착형성이었다. 결론 시험불안의 원인적 측면에서 볼 때 기질특성 특히 위험 회피 기질과 불안정한 애착이 중요하다고 판단되었다. Objectives : Through mass survey with Seoul School Health Center, this study was performed to find out any correlational factors that affect test anxiety in individual's temperament and attachment type among middle and high school students in Seoul. Methods : Subjects were 4,178 students from 6 middle schools, 5 high schools and 1 technical high school in this study from May to June, 2005. Test Anxiety Inventory (TAI) by Spielberger, Revised Adult Attachment Scale (RAAS) by Collins and Read and Junior Temperament Character Inventory (JTCI) by Ludy were used in this study. Results : Among 4 groups by sex and age, high school girls had the highest level of test anxiety and high school boys had the lowest level of test anxiety. The attachment subscore showed no significant differences in four groups. High school girls had higher social susceptibility but had lower novelty seeking subscores than high school boys. Middle school students revealed no meaningful differences of temperament between sex. Compared to low test anxiety group, high test anxiety group showed significantly high anxiety subscores in attachment scale and high harm avoidance subscores in temperament scale. However, the results of other three subscores of temperament and two subscores of attachment were reversed. Anxiety subscore of attachment and harm avoidance subscore of temperament positively correlated with test anxiety score (r=0.26, r=0.32). However, other subscores negatively correlated with test anxiety score and the correlation coefficient scores were very low. Conclusion : We concluded that, in temperament and attachment aspect, the most important factor affecting test anxiety was harm avoidance temperament and the next important factor was anxious attachment.

경북 봉화와 강원도 간성 지역의 송이자생지 산림토양의 특성

정덕영(Chung, Doug-Young),이교석(Kyo-S. Lee),이종신(Jong-Shin Lee),윤영남(Young-Nam Youn),Yoon-Cheol Choi 한국토양비료학회 2008 한국토양비료학회지 Vol.41 No.3

본 연구는 2005년에 송이가 자생하고 있는 지역으로 상대적으로 비교가 되는 기후특성을 가지고 있으며 최북단과 최남단 지역인 경북 봉화와 강원 간성지역 토양의 이화학특성을 조사한 것이다. 송이균사는 임목밀도와 유기물층 하부의 토양수분함량이 상대적으로 높은 봉화지역에서 발생비율이 높았다. 그리고 토 양수분함량은 유기물 두께가 증가할수록 토양내 수분 함량도 증가하는 것으로 조사되었다. 따라서 송이균사의 발생과 발생밀도는 토양수분과 밀접한 관련이 있음을 알 수 있다. 한편 토양내 성분을 조사한 결과 송이가 발생한 지점의 철(iron) 이온의 함량이 미 발생지점보다 높았다. 그리고 철이온의 함량이 높은 지점에서 자갈의 비율은 송이균사가 존재하지 않는 지점보다는 상대적으로 낮았다. 이는 토양내 점토 함량이 높을수록 점토입자 표면에 흡착된 철이온의 용탈이 감소된 것으로 추정된다. 결론적으로 송이균사의 존재는 토양수분과 균사가 존재하는 토양내 수분함량과 철이온의 농도에 의해 결정되는 것으로 추정할 수 있다 We observed the physical and chemical properties of a soil on pine mushroom picking areas where were located in the most upper and lower parts showing a comparative climatic characteristics in Korea. The slope gradients within the investigation areas which were divided into 100 quadrates of 1 m<SUP>2</SUP>ranged from 5.7~8.6ß to 24~22.7ß (left to right) and 4.5~6.8ß to 13.5~17.8ß (top to bottom) for Ponghwa and Gansung, respectively. The amount of clay and thickness of organic matter were significantly decreased with increasing slope gradient, resulting in decrease of the soil moisture content around a fairly ring-colony of Tricholoma matsutake which was observed under the relatively thicker organic matter layer beyond 3 cm depth. Soil pHswere weak acid and average EC was 0.44 dS m<SUP>-1</SUP> in both areas. The cations were in the order of Fe K > Na > Mg > Ca and Fe > K > Na > Ca > Mg for the upper(Gansung) and the lower (Ponghwa) part. And the amount of Fe was approximately 80 mg kg<SUP>-1</SUP> or greater in the pine mushroom picking soil. From this, we could assume that the growth of the pine mushroom was closely related not only with iron but also soil moisture content.

The surface profile and biocompatibility of hydroxyapatiteblasted gold membrane as a periodontal guided tissue regeneration membrane

Jin, Kangsik,Youn Lee, Doug,Je, Jina,Keun Lee, Yong,Nam Kim, Kyoung,Mahn Kim, Kwang John Wiley Sons, Ltd. 2010 Surface and interface analysis Vol.42 No.6

<P>Guided tissue regeneration (GTR) membrane is essential for periodontal surgery, GTR membrane can guide successful bone tissue formation. The aim of this study is to assess morphologic property and biocompatibility of hydroxyapatite (HA) blasted gold membrane as a periodontal GTR membrane. 99.99 gold (LS Nikko, Korea) was rolled to 0.025∼0.050 mm thickness, and then, blasted with hydroxyapatite powder (5 ∼ 25 µm, Ossgen, Korea) onto the rolled gold sheets. Contact angle measurement of non-blasted and HA-blasted surface was performed. And, scanning electron microscopy analysis (simple surface profile observation and observation after attachment of human osteosarcoma cell) was performed. In implantation test using adult dog, Ti-membrane (Implantium, Suwon, Korea) was used as a control group, and HA-blasted gold membrane was used as a experimental group. Contact angle of HA-blasted gold membrane was higher than that of non-blasted gold surface (p < 0.05). In SEM analysis, HA-blasted gold membrane showed roughened surface and attachment of MG-63 cell was more than that of non-blasted gold surface. There were not any specific clinical symptoms and histological signs in implantation test. This result shows that HA-blasted gold membrane has a possibility as promising periodontal GTR membrane. Copyright © 2010 John Wiley & Sons, Ltd.</P>

A comparison of chlorhexidine release rate from three polymeric controlled release drug prototypes

Bok, Young-Bin,Lee, Doug-Youn,Lee, Chang-Young,Kim, Kyung-Nam,Kum, Kee-Yeon 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.6

Intracanal disinfection of infected root canal is one of important treatment procedure. This in vitro study aimed to evaluate whether the surface polymers of controlled release drug (CRD) can effectively control the release rate of chlorhexidine for root canal disinfection. Four CRD prototypes were prepared: Group A (n=12); The core device (absorbent paper point) was loaded with 40% CHX solution as control. Group B (n=12); same as group A, but the device was coated with chitosan. Group C (n=12); same as group A and then coated three times with 5% PMMA. Group D (n=12); same as group A and then coated three times with 3% PLGA. All CRD prototypes were soaked in 3 mL distilled water for experimental periods and the concentrations of released CHX from each CRD prototype were determined using a UV spectrophotometer. Results showed that release rate of CHX were the greatest in the non-coated group (control group), followed by the chitosan-coated group, the PLGA-coated group, and the PMMA-coated group (P <0.05). This data indicate that surface polymers can control the release rate of CHX from the CRD prototypes. 본 연구는 제어방출형 근관소독제(CRD)로 부터 chlorhexidine (CHX)의 방출 속도를 제어하기 위한 3가지 polymer (chitosan, PMMA, PLGA) 의 코팅 효과를 평가하기 위함이다. 80번 paper point (Sure-Endo)에 20% CHX를 loading 한 후 각 군당 10개씩 4군으로 분류하였다: Group A: 폴리머를 코팅하지 않은 CRD prototype (control), Group B: chitosan-coated prototype, Group C: PMMA-coated prototype, Group D: PLGA-coated prototype. 모든 시편은 3 ml 증류수가 담긴 큐벳에 넣은 후 3, 6, 10, 20, 30, 40, 50분 마다, 1, 2, 3, 4, 5, 6시간 마다 각각 10 μl 씩 채취하고, 1주일 후 다시 10 μl을 채취한 후 UV 흡광도를 이용하여 CHX의 방출 속도를 비교하였다. 실험결과 제어방출형 근관소독제로부터 CHX의 방출속도는 대조군, 키토산, PLGA, PMMA-군 순으로 천천히 일어났으며 PMMA군에서 가장 천천히 일어났다. 결론적으로 제어방출형 근관소독제 표면의 폴리머는 약물 (CHX) 방출 속도를 효과적으로 제어하였다.

Change of surface property of dental impression materials according to time and disinfection

Kim, Soo-Hwa,Lee, Doug-Youn,Kim, Kwang-Mahn,Kim, Kyoung-Nam John Wiley Sons, Ltd. 2008 Surface and interface analysis Vol.40 No.3

<P>The purpose of this study was to investigate the hydrophilicity of dental impression materials. Two ultrahydrophilic (Fusion, Genie) and four hydrophilic (Imprint II, Aquasilultra, Twinz, Perfect-F) impression materials were used. Initially, 0.5% NaOCl and 1% povidone were used as disinfectants. In order to investigate the change of the surface wettability of impression materials according to the elapsed time after mixing, the contact angles were measured at 30 s and 2 min after mixing, respectively. Contact angles were also measured before and after disinfection. The contact angles of the ultrahydrophilic impression materials were lower at 2 min than at 30 s, whereas those of the hydrophilic impression materials showed the opposite result (p < 0.05). Fusion and Perfect-F had higher contact angles in the NaOCl-group and lower contact angles in the povidone-group than those of nondisinfection group (p < 0.05). The contact angles of Aquasilultra and Twinz in the povidone-group were higher than those in the nondisinfection group (p < 0.05). The elapsed time after mixing and disinfection of impression materials affected the contact angle of water on the surface of the impression materials. These results suggested that impression materials should only be used within the scope that their wettability is not degraded. Copyright © 2008 John Wiley & Sons, Ltd.</P>