• 제목/요약/키워드: bond test

검색결과 1,572건 처리시간 0.025초

제 2급 와동에서 구치부 복합레진의 미세변연누출에 관한 연구 (MICROLEAKAGE OF POSTERIOR PACKABLE COMPOSITE RESIN hi THE GINGIVAL MARGINS OF CLASS II CAVITIES)

  • 최수진;김미자;권혁춘
    • Restorative Dentistry and Endodontics
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    • 제27권3호
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    • pp.249-256
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    • 2002
  • The use of flowable composite resins as liners in class II packable composite restoration has been suggested by some manufacturers. However, the contributions of this technique are unproven. The purpose of this study was to compare the gingival microleakage in class II packable composite restorations with or without the use of flowable composite resins as liners. Slot cavities were prepared on both proximals of 80 extracted human molars and randomly assigned to 8 groups of 20 each. The gingival margins were located at 1mm above CEJ in 80 cavities (group1-4) and 1mm below CEJ in 80 cavities (group5-8). The prepared teeth were mounted in the customized tray with adjacent teeth to simulate clinical conditions and metallic matrix band (Sectional matrix) and wooden wedges were applied. After acid etching and application of Single Bond, each group was restored with the following materials using incremental placement technique: Group 1,5 (Filtek P60), group 2, 3, 4 and group 6, 7, 8 (AeliteFlo, TetricFlow, Revolution/ Filtek P60). All specimens were thermocycled 500 times between 5$^{\circ}C$ and 55$^{\circ}C$ with 1 mimute dwell time, immersed 2% methylene blue dye for 24 hours and then rinsed with tab water. The specimens were embedded in clear resin and sectioned longitudinally through the center of restoration with a low speed diamond saw. Dye penetration at gingival margin was viewed at 20 magnification and analyzed on a scale of 0 to 4. Kruscal-Wallis One way analysis and Mann-Whitney Rank sum test were used to analyze the results. The results of this study were as follows. 1. The leakage values seen at the enamel margin were significantly lower than those seen at the dentin margin(P<0.05). 2. On the enamel margin, packable composite resins with flowable liners showed lower leakage than those without flowable liners, but there were no significant differences among the four groups(P>0.05). 3. On the dentin margin, four groups demonstrated moderate to severe leakage, and there were no significant differences in leakage values(P>0.05).

음이온 계면활성제에서 파파인 효소의 안정도에 관한 연구 (A Study on the Stabilization of the Papain Enzyme in the Moderately Concentrated Anionic Surfactant System)

  • 김지영;김진우;김용진;이재욱;이해광;강학희
    • 대한화장품학회지
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    • 제33권2호
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    • pp.93-97
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    • 2007
  • 일반적으로 음이온 계면활성제는 효소의 disulfide bond를 분해시켜 효소의 활성이 없어진다. 따라서 특정한 캡슐에 효소를 포집하여 안정도를 증대시킨다. 본 연구에서는 polyethylene glycol (PEG), polypropylene glycol (PPG), 그리고 PEG-PPG-PEG block copolymer 등의 폴리올을 이용하여 papain 효소의 안정도를 증대시켰다. Energy dispersive spectroscopy (EDS)와 confocal laser scanning microscope (CLSM) 분석을 통하여 폴리올은 고분자층과 효소의 중간에 위치하며, 이들은 완충액으로 작용하여 효소의 안정도를 증대시키는 것으로 확인하였다. 또한, 이온 복합체를 이용하여 다층 캡슐을 제조하여 wash-off 형태의 세정제에 응용하였다. 세정제 내에서 계면활성제와 물은 효소캡슐의 표면에 분산되었으며, 캡슐의 중앙부분으로 서서히 침투되었다. 반면에 본 연구에서 사용된 sodium lauroyl sarcosinate와 polyguaternium-6는 물이 효소부분으로 침투하지 않는 것을 in vivo 시험을 통하여 확인하였다.

Pharmacophore Identification for Peroxisome Proliferator-Activated Receptor Gamma Agonists

  • Sohn, Young-Sik;Lee, Yu-No;Park, Chan-In;Hwang, S-Wan;Kim, Song-Mi;Baek, A-Young;Son, Min-Ky;Suh, Jung-Keun;Kim, Hyong-Ha;Lee, Keun-Woo
    • Bulletin of the Korean Chemical Society
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    • 제32권1호
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    • pp.201-207
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    • 2011
  • Peroxisome proliferator-activated receptors (PPARs) are members of nuclear receptors and their activation induces regulation of fatty acid storage and glucose metabolism. Therefore, the $PPAR\gamma$ is a major target for the treatment of type 2 diabetes mellitus. In order to generate pharmacophore model, 1080 known agonists database was constructed and a training set was selected. The Hypo7, selected from 10 hypotheses, contains four features: three hydrogen-bond acceptors (HBA) and one general hydrophobic (HY). This pharmacophore model was validated by using 862 test set compounds with a correlation coefficient of 0.903 between actual and estimated activity. Secondly, CatScramble method was used to verify the model. Hence, the validated Hypo7 was utilized for searching new lead compounds over 238,819 and 54,620 chemical structures in NCI and Maybridge database, respectively. Then the leads were selected by screening based on the pharmacophore model, predictive activity, and Lipinski's rules. Candidates were obtained and subsequently the binding affinities to $PPAR\gamma$ were investigated by the molecular docking simulations. Finally the best two compounds were presented and would be useful to treat type 2 diabetes.

섬유혼입조건 및 팽창재 대체에 따른 변형 경화형 시멘트 복합체 내의 철근 겹침이음 성능 (Effects of Fiber Blending Condition and Expansive Admixture Replacement on Tensile Performance of Rebar Lap Splice in Strain-Hardening Cement-Based Composites (SHCCs))

  • 류승현;이영오;윤현도
    • 콘크리트학회논문집
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    • 제24권2호
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    • pp.111-120
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    • 2012
  • 이 연구는 섬유 보강 시멘트 복합체(SHCC) 내에 매립된 철근의 겹침이음 성능을 평가하고자 하였으며, 이에 따라 단조 및 반복 재하시의 겹침이음된 철근의 인장 실험을 실시하였다. 총 10개의 SHCC 및 콘크리트 배합이 계획되었으며, 실험체의 변수는 보강섬유 종류(폴리에틸렌 및 강섬유), 팽창재 대체율(0% 및 10%) 및 실험체의 설계강도(30 MPa 및 100 MPa)로 계획하였다. SHCC 및 콘크리트 배합에 매립된 철근의 겹침이음 길이는 각각 콘크리트 구조설계 기준에 의거하여 산정된 겹침이음 길이의 60% 및 100%를 적용하였다. 실험 결과 SHCC에 철근이 매립될 경우 철근의 겹침이 음 성능을 향상시키는 것으로 나타났으며, SHCC 배합에서 보강 섬유 종류(PE-SHCC 및 PESF-SHCC)에 관계없이 겹침 이음된 철근의 인장강도 및 부착강도 증진에 기여하는 것으로 나타났다. 또한 SHCC에 팽창재를 대체할 경우 SHCC에 매립된 철근 겹침이음부의 거동 특성을 개선하는 특징을 보였다. 한편 균열 특성에서는 배합조건 및 재료특성에 따라 PE-SHCC가 PESF-SHCC에 비해 보다 많은 미세균열 특성을 나타내었다. 전언한 바와 같이 이 연구는 SHCC의 변형경화 특성에 따라 매립된 철근과의 상호작용을 증진시킴에 따라, SHCC에 매립된 철근 겹침이음 길이를 감소할 경우에도 양호한 거동 특성을 보이는 것으로 판단된다.

벼멸구의 저항성 유발, 교차저항성 및 저항성 유전에 관한 연구 (Cross-resistance and Inheritance of Resistance in Laboratory-selected Strains of the Brown Planthopper(Nilaparvata lugens Stal))

  • 박형만;최승윤
    • 한국응용곤충학회지
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    • 제30권1호
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    • pp.1-9
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    • 1991
  • 벼멸구를 fenobucarb, carbofuran및 diazinon 등 3종의 살충제로 누대선발하여 얻어진 저항성 별멸구를 대상으로 저항성 유발, 교차저항성 및 저항성 유전에 대해서 조사한 결과를 보고하고자 한다. Fenobucarb, carbofuran으로 18세대, diazinon으로 14세대 누대선발한 결과 각 선발 계통의 반수치사약량은 50.3배, 49.2배 및 5.8배씩 증가하였다. Fenobucarb 및 carbofuran 선발계통은 carbamate계 살충제에 각각 17.7-42.2배, 19.4-40.8배의 높은 교차저항성을 보였고, 분지구조 중 carboxyl ester bond를 가지고 있는 malathion, phenthoate에 대해서도 13.0-12.0배, 8.5-7.5배로 다른 유기인계 살충제에 비하여 높은 교차저항성를 나타내었으며, cypermethrin및 deltamethrin에도 diazinon선발계통에 비하여 3-7배 정도 높은 교차저항성을 보였다. diazion선발계통은 유기인계 살충제(평균 5.0배) 및 카바메이트계 살충제(평균 7.0배)에서 diazion 수준(5.8배)의 교차저항성을 보였다. Fenvalerate에 대한 교차 저항성은 fenobucarb 및 carbofuran 선발 계통에서 낮았으며 diazinon 선발계통에서는 역상관 교차저항성으로 나타났다. 벼멸구의 살충제 저항성은 교잡종($F_1$)의 우성도가 암컷에서 0.54-0.70, 수컷에서 0.45-0.80으로 나타나 상염색체상의 불완전우성 유전자에 의해 유전되는 것으로 판단된다.

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대도시, 중소도시, 농촌 노인의 건강상태에 관한 연구 (A Study of the Health Status of Elderly Residing in Large city, Medium and Small city, Rural areas in Korea)

  • 최영희;신윤희
    • 대한간호학회지
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    • 제21권3호
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    • pp.365-382
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    • 1991
  • This study was designed to measure the physical, mental-emotional and social health status of elderlies according to rural areas, medium - small cities, and large city environment. Data collection was done from July 18 to August 17 1990. The subjects were a convenience sample after their place of residence was stratified into large, medium- small cities and rural areas. Those who attended elderly centers in Seodaemun, Mapo, and Kangnam districts in Seoul were considered to be residents of a large city and interviewed by trained research assistants and student nurses. Elderlies living in Chungju, Jinju, Chuncheon, and Jeonju cities were coded as residents of medium-small cities and were interviewed by professors of nursing colleges. Rural residents were interviewed by the community health practioners working in community health clinics in North and South Kyongsang, North and South Jeolla, and Kyonggi provinces. The tool used in this study was the health assessment tool developed by Choi, Young Hee in 1990. This tool was organized into 20 physical health status, 17 mental - emotional health status, and 37 social health ststus items. Physical health status items consisted of six factors - personal hygiene activity ability, external activity utilizing traffic, mass media, and spare time ability, sexual ability, digestive system related ability, sexual ability, sensory ability, and elimination ability. Mental - emotional health status items consisted of two factors - mental health factor and emotional health factor. Social health status items consisted of seven factors -grandparental role ability, parental role ability, spoused role ability, friendship role ability, kinship role ability, group member role ability, and religious believer role ability. Data Analysis included frequencies, percentage, mean, standard deviation, ANOVA, and chi - square test. The results of the analysis are as follows : 1. The mean physical health status score for large city residents was 4.1132, for rural residents 4.0787, and for medium and small city residents 3.9565. There were significant differences according to residential area for personal hygiene activity ability, external activity ability, sexual ability, and digestive system related ability items 2. The mean mental -emotional health status score for rural residents was 3.8291, for medium and small city residents 3.7967, and for large city residents 3.7807. There was a significant difference according to residential area in the mental health ability item. 3. The mean social health status score for medium and small city residents was 3.0000, for rural residents 2.9362, and for large city residents 2.8960. There were significant differences according to residential area for kinship role ability and religious believer role ability items. The following conclusion was derived from the above results 1. The physical health status of elderlies residing in medium - small cities and in rural areas was lower than that of those residing in Seoul, a large urban area. Therefore, more medical facilities are needed in rural area so as to monitor their health, prevent disease, and promote their health. 2. The mental -emotional ststus and social health status of elderlies residing in the large city were lower than that of those residing in medium - small cities and rural areas. This may reflect weakening of the strong traditional family bond that may happen with urbanization. Continued support for elderly parents is essential and education should emphasize the traditional cultural norm and value of filial piety. 3. Facilities and programs for elderly are needed so that they may spend their time more valuably in their urban environment.

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Surface characteristics of a novel hydroxyapatite-coated dental implant

  • Jung, Ui-Won;Hwang, Ji-Wan;Choi, Da-Yae;Hu, Kyung-Seok;Kwon, Mi-Kyung;Choi, Seong-Ho;Kim, Hee-Jin
    • Journal of Periodontal and Implant Science
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    • 제42권2호
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    • pp.59-63
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    • 2012
  • Purpose: This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. Methods: HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. Results: A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. Conclusions: These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants.

알카리저항 초단유리섬유를 리브에 사용한 유리섬유 보강근의 내구성능 (Durability of GFRP Rebar with Ribs Containing Milled Alkaline Resistant Glass Fibers)

  • 문도영;오홍섭
    • 한국구조물진단유지관리공학회 논문집
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    • 제15권1호
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    • pp.281-287
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    • 2011
  • GFRP 보강근은 콘크리트의 알칼리성분에 의해 손상 받을 수 있다. 본 논문은 이형 GFRP 보강근의 알칼리에 대한 내구성을 증진시키기 위한 방법에 대한 실험적 연구이다. 기존 개발된 이형 GFRP 보강근의 표면물질에 삽입되는 초단유리섬유는 콘크리트와의 부착성능을 향상시키는 것으로 알려져 있다. 본 논문에서는 초단 알칼리저항섬유(AR-glass)와 E-glass 섬유를 표면이형의 구성물질로 활용하였을 때, 보강근의 내구성능에 미치는 영향을 흡습시험과 ISS 실험을 통하여 규명하고자 하였다. 혹독한 실내실험조건을 위하여 $40^{\circ}C$의 온도가 적용되었다. 실험결과, 표면성형을 위한 레진과의 합성물로써, E-glass와 AR-glass를 사용하였을 때, 내구성능에 큰 차이는 없는 것을 확인하였다. 오히려, 레진과 섬유의 혼합비가 작업성과 성형성에 영향을 미치고, 이것이 표면 이형부에 공극을 만들게 됨으로써, 큰 영향을 미치는 것으로 나타났다. 따라서, 장기적인 내구성능 확보를 위해서 혼입률의 결정에 주의를 기울여야 한다.

제초성 Benzenesulfonyl urea계 화합물의 형태와 반응성 (Conformation and Reactivity of Herbicidal Benzenesulfonyl urea Compounds)

  • 유성재;이상호;고영관;성낙도
    • Applied Biological Chemistry
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    • 제39권3호
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    • pp.235-240
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    • 1996
  • 제초성 비치환(H) benzenesulfonyl urea 분자, 1은 sulfonyl group 인접의 amino group과 pyrimidinyl group의 N원자 사이에 회합(H-결합)된 형태(II-keto)가 제일 안정하였으며 phenyl 치환$(R_2$$R_3)$유도체, 2는 전자를 밀수록$(\sigma<0)$ LUMO(ev.)는 음의 값으로 증가하여 물 분자의 HOMO(ev.)사이에 궤도 조절반응(p<0)에따른 전형적인 친핵 반응성을 나타낸다. N-(4,6-이치환-pyrimidine-2-yl)aminocarbonyl-2-(1,1-dimethoxy-2-fluoro)ethylbenzenesulfonamides, 3 및 N-(4,6-이치환-triazine-2-yl)aminocarbonyl-2-(1,1-dimethoxy-2-리uoro)ethylbenzenesulfonamide, 4 유도체의 4,6-이치환기(X 및 Y) 와 헤테로 고리의 변화에 따른 올챙이고랭이(Scirpus juncodies.) 에 대한 제초활성은 소수성$((log\;P)_{opt.}=0.89)$이 가장 큰 영향을 미치는 요인이었다. 또한, pyrimidine-치환체, 3이 triazine-치환체, 4보다 양호한 제초활성을 나타내었으며 dimethoxypyrimidine-치환체, 3a가 가장 큰 제초활성을 보였다.

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소변 중 4-hydroxyproline 분석에 관한 연구 (Determination of Free 4-hydroxyproline with Dansylchloride by HPLC in Human Urine)

  • 이규원;조영봉;이경종
    • Journal of Preventive Medicine and Public Health
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    • 제35권4호
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    • pp.282-286
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    • 2002
  • Objectives : The level of 4-hydroxyproline (4-Hyp) in human urine was measured using high performance liquid chromatography (HPLC) with a fluorescence detector. This method is useful for medical examinations and investigating the radicals induced by physical, chemical, mental stresses. This method is superior to many published several methods in terms of its low cost and ability to analyze many samples. Methods : The urine from workers in a tire manufacturing company (22 male pre- and post-shift workers) and 18 office-workers as controls were analyzed. Data concerning age, the cumulative drinking amount and the cumulative smoking amount was collected with a questionnaire. The optimum applied amount of dansyl-Cl, the optimum reaction temperature and time, the recoveries and the optimum pH of the eluent and buffer were determined.4-Hyp from human urine was derivatized with dansyl-Cl (dimethylamino-naphthalene-1-sulfonyl chloride) after removing the a-amino acid by a treatment with phthalic dicarboxaldehyde (OPA) and cleaned with Bond Elut C18 column. The 4-Hyp derivatives were separated on a reversed phase column by gradient elution with a phosphate buffer (5 mmol, pH 8.0) and acetonitrile, and detected by fluorescence measurements at 340 nm (excitation) and 538 nm (emission). Results : The detection limit for the urinary free 4-Hyp was $0.364{\mu}mol/l$. The recovery rate of 4-Hyp was 99.7%, and the effective pH of the phosphate buffer and borate buffer were 3.0 and 8.0, respectively. From statistical analysis, age, drinking and smoking did not affect the urinary free 4-Hyp in both the controls and workers. The range of urinary 4-Hyp in the controls, pre-shift, and post-shift workers were 0.33-16.44, N.D-49.06, and $0.32-56.27{\mu}mol/l$. From the pared-sample t-test, the urinary 4-Hyp levels in post-shift workers ($11.82{\pm}6.73\;nmmol/mg\;Cre$) were 2-fold higher than in pre-shift workers ($5.36{\pm}5.53\;nmol;/mg\;Cre$) and controls ($4.91{\pm}4.89\;nmol;/mg\;Cre$). Conclusions : This method was developed with high sensitivity, accuracy, and precision. The present method was effectively applied to analyze the urinary free 4-Hyp in both controls and workers.