• IMMUNE NETWORK
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• 제4권4호
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• pp.250-254
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• 2004

Background: It is necessary for human beings to uptake vitamin C through diet or supplements. It is also well-known that vitamin C plays an important role in the prevention of scurvy, enhancement of collagen synthesis and anti-tumor immune response. In addition, there are several recent reports regarding the effective role of vitamin C on the regulation of allergic responses, such as atopic dermatitis and asthma. However, the effective therapeutic and preventive measures using vitamin C are not established yet, since vitamin C is seriously unstable in aqueous solution. Therefore, we have investigated the best way to maintain the stability of vitamin C. Methods: After we making a mixture of polyphenol (0.001, 0.01, 0.1%) and vitamin C (1 mM), the mixtures were placed at room temperature both with/without light protection. And then the concentration of ascorbic acid was measured with HPLC. To analyze the in vivo effect of vitamin C on the regulation of skin allergic reaction, polyphenol (0.1%)-vitamin C (1 mM) mixture was applied to the skin and the production of histamine from mast cell was analyzed by Evans blue dye staining. Results: We have found that the polyphenol has preventive power of oxidation of vitamin C. In addition, the production of histamine was suppressed by the polyphenol (0.1%)-vitamin C (1 mM) mixture. Conclusion: We have reached the conclusion that our study suggests the research guideline for the therapy of atopic dermatitis through vitamin C.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.254-266
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• 1996

The purpose of this study was to evaluate the degree of marginal leakage that is made by wet bonding to dentin and dissolution of dentinal collagen layer in vivo and in vitro. Class V cavities were prepared to 32 cat's canine teeth and they were randomly assigned into the following 4 groups : Group 1 (not acid conditioned) ; Group 2 (acid-conditioned and blot-dried) ; Group 3 (acid-conditioned and air-dried for 30 seconds) ; Group 4 (acid-conditioned and retreated with 10% NaOCl solution). The acetone-based primer and bonding agent of All Bond 2(Bisco Inc., U.S.A.) and composite resin(Z-100, 3M. Dent. Prod., U.S.A.) were then applied. The resin collar and cap attached to each specimen and 50% silver nitrate solution was placed inside the resin cap for 3 hours. After the canine tooth was resected in level of cervical third, specimens were highly polished and observed the degree of the dye penetration on incisal and gingival margins. The results were as follows ; 1. There was no significant difference of marginal leakage in all the groups between in vivo and in vitro. 2. In vivo, the degree of leakage on the gingival margin showed the lowerest in group 4 and followed by group 2, 3 and group 1 with ascending order. However, there was no statistical difference among all the groups(p>0.05). 3. In vitro, the degree of leakage on the gingival margin showed the lowerest in group 2 and followed by group 4, 3 and group 1 with ascending order. However, there was no significant difference among the experimental groups(p>0.05). 4. The marginal leakage of the incisal margin in vitro was significantly higher in group 1 than the remaining groups(p<0.05).

• 대한치과교정학회지
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• 제41권1호
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• pp.51-58
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• 2011

Objective: To evaluate the shear bond strength (SBS), fracture mode, wire pull out (WPO) resistance and microleakage between low-shrinking and conventional composites used as a lingual retainer adhesive. Methods: A total of 120 human mandibular incisor teeth, extracted for periodontal reasons, were collected. Sixty of them were separated into two groups. To determine the SBS, either Transbond-LR (3M-Unitek) or Silorane (3M-Espe) was applied to the lingual surface of the teeth by packing the material into standard cylindrical plastic matrices (Ultradent) to simulate the lingual retainer bonding area. To test WPO resistance, 20 samples were prepared for each composite where the wire was embedded in the composite materialand cured. Then tensile stress was applied until failure of the composite occurred. The remaining 60 teeth were divided into two groups and multi-stranded 0.0215-inch diameter wire was bonded with the same composites. Microleakage was evaluated by the dye penetration method. Statistical analyses were performed by Wilcoxon, Pearson chi-square, and Mann-Whitney-U tests at p < 0.05 level. Results: The SBS and WPO results were not statistically significant between the two groups. Significant differences were found between the groups in terms of fracture mode (p < 0.001). Greater percentages of the fractures showed mix type failure (85%) for Silorane and adhesive (60%) for Transbond-LR. Microleakage values were lower in low-shrinking composite than the control and this difference was found to be statistically significant (p < 0.001). Conclusions: Low-shrinking composite produced sufficient SBS, WPO and microleakage values on the etched enamel surfaces, when used as a lingual retainer composite.

• 마이크로전자및패키징학회지
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• 제15권2호
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• pp.47-54
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• 2008

컴포넌트에서의 비정상적인 금속간화합물 성장이 보드 레벨 기계적 신뢰성에 미치는 영향을 연구하기 위하여, 전기 도금된 Ni/Au UBM과 Sn2.5Ag0.5Cu 솔더의 리플로우 횟수 및 고온 시효 시간에 따른 금속간 화합물 성장거동을 관찰하였다. 각 조건별로 처리된 컴포넌트에서 솔더 접합부의 기계적 특성을 비교하기 위하여, 전단 속도 변화에 따른 볼 전단 시험을 실시하여 전단에너지 값을 측정하였다. 마지막으로, 보드 레벨에서의 기계적 신뢰성 시험을 위하여 조건별로 처리된 컴포넌트를 PCB 보드에 실장하여, 3점 굽힘 시험 및 충격 시험을 실시한 후 파괴모드를 분석하였다.

• 구강회복응용과학지
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• 제27권3호
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• pp.305-316
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• 2011

균열치는 저작운동과 온도자극에 대한 치아의 통증을 호소하는 환자에서 자주 발견되는 질환으로 균열의 진행정도에 따라 다양하게 분류할 수 있다. 가장 흔한 원인으로는 저작과정 중의 갑작스러운 사고로 알려져 있지만 대부분 증령, 기존 수복물 또는 의원성 응력집중과 같은 기여요인이 있을 때 발생한다. 균열의 진행정도 및 치수침범에 대한 정확한 진단이 필수적이며 저작시 통증을 확인한 후 균열을 가급적 눈으로 확인하는 것이 좋다. 이를 위해 투과광이나 염색과 같은 보조적 방법을 이용할 수 있다. 치료는 즉각적인 통증완화를 위한 교합조정이나 파절편 고정이 필요하며 치수의 상태에 따라 근관치료가 추가적으로 필요할 수도 있다. 궁극적인 치료로는 복합레진이나 접착 아말감으로 균열부위에 가해지는 충격을 완화시킨 후 주조수복물을 이용한 교두보호가 필요하다. 이 논문에서는 균열치에 대한 다양한 원인, 치료, 예후 등에 관한 문헌을 고찰할 것이다.

• Journal of Pharmaceutical Investigation
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• 제36권1호
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• pp.1-9
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• 2006

Human solid tumors exhibit a multicellular resistance (MCR) resulting from limited drug penetration and decreased sensitivity of tumor cells when interacting with their microenvironments. Multicellular cultures represent solid tumor condition in vivo and provide clinically relevant data. There is little data on antitumor effect of paclitaxel (PTX) in multicellular cultures although its MCR has been demonstrated. In the present study, we evaluated antiproliferative effects of PTX in multicellular layers (MCL) of DLD-1 human colorectal carcinoma cells. BrdU labeling index (LI), thickness of MCL, cell cycle distribution and cellular uptake of calcein were measured before and after exposure to PTX at 0.1 to 50 ${\mu}M$ for 24, 48 and 72 hrs. BrdU LI and thickness of MCL showed a concentration- and time-dependent decrease and the changes in both parameters were similar, i.e., 34.2% and 40.6% decrease in BrdU LI and thickness, respectively, when exposed to $50\;{\mu}M$ for 72 hr. The DLD-1 cells grown in MCL showed increase in $%G_{0}/G_{1}$ and resistance to cell cycle arrest and apoptosis compared to monolayers. Calcein uptake in MCL did not change upon PTX exposure, indicating technical problems in multicellular system. Overall, these data indicate that antitumor activity of PTX may be limited in human solid tumors (a multicellular system) and MCL may be an appropriate model to study further pharmacodynamics of PTX.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.447-462
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• 1993

To evaluate the marginal leakage in Class V cavity this study has been undertaken to compare the sandwich technique with the conventional method, and find out the effect of lining material, lining method, and polishing time on sandwich technique. Ninty extracted teeth were divided into eight test groups and a control group, and were prepared with a buccal Class V cavity. Four test groups were lined with Dentin Cement whereas the other four test groups were lined with Vitrabond. Half of the either group were lined 0.5mm short of the carvosurface margin and the rest were lined completely to the carvosurface margin. The four subgroups were further divided into specimens which were polished immediately and 24 hours after resin filling. The polished specimens were immersed in $37^{\circ}C$, 0.5% methylene blue solution for 24 hous after thermocycling at $5^{\circ}C$ and $55^{\circ}C$, 200 times and buccolingually sectioned. The sectioned specimens were examined dye penetration under the light microscope. The following results were obtained, 1. At the enamel margin, the conventional method showed a lower microleakage than the sandwich technique. The difference between the control and Vitrabond group was statistically significant(P<0.05), but no difference between the control and Dentin Cement group, and between the lining materials was observed. 2. At the dentinal margin, the sandwich technique showed a significant lower amount of microleakage (P<0.05), but there was no significant difference between the lining materials. 3. Regardless of the lining material, lining method, and polishing time used, values of microleakage were significantly higher at the dentinal margin compared to the enamel margin(P<0.05). 4. In specimens till the cavosurface margin, microleakage at the dentinal margin was less with the light-cured base than with the chemically-cured base, but there was no siginificantly difference between the lining materials regarding the lining method and polishing time. 5. The lining material, lining method, and polishing time did not affect the amount of micro leakage in the sandwich technique(P<0.05).

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.172-179
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• 2014

Objectives: This study aimed to assess the effect of 38% carbamide peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites. Materials and Methods: A total of 96 class V cavities were prepared on the buccal surface of extracted human teeth with both enamel and dentin margins and were randomly assigned into three groups of Filtek P90 (3M-ESPE) + P90 system adhesive (3M-ESPE)(group A), Filtek Z250 (3M-ESPE) + Adper Prompt L-Pop (3M-ESPE)(group B) and Filtek Z350XT (3M-ESPE) + Adper Prompt L-Pop (group C). Half of the teeth were randomly underwent bleaching (38% carbamide peroxide, Day White, Discus Dental, applying for 15 min, twice a day for 14 day) while the remaining half (control) were not bleached. Dye penetration was measured following immersion in basic fuchsine. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at a level of 0.05. Results: No significant differences were found between composites in the control groups in enamel (p = 0.171) or dentin (p = 0.094) margins. After bleaching, microleakage of Z250 (in enamel [p = 0.867] or dentin [p = 0.590] margins) and Z350 (in enamel [p = 0.445] or dentin [p = 0.591]margins) did not change significantly, but the microleakage of P90 significantly increased in both enamel (p = 0.042) and dentin (p = 0.002) margins. Conclusions: No significant differences were noted between the bleached and control subgroups of two methacrylate-based composites in enamel or dentin margins. Microleakage of silorane-based composite significantly increased after bleaching.

• 한국염색가공학회지
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• 제29권3호
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• pp.122-130
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• 2017

In the direct digital textile printing process, the pre-treatment process is an essential condition for products by forming a clear pattern by sticking and penetration of DTP dye without spreading on the fabric. Recently, pre-treatment agent is changing from high viscosity to low viscosity in order to reduce defects of fabric during pre-treatment process. In this study, pre-treatment agent of acrylic polymer with low viscosity(less than 50cps) was prepared according to the solid content of the polymer, pre-treated on the cotton fabric, and direct DTP printing was performed to compare the color and sharpness. As a result, it showed high color at a viscosity of 50cps or less. When the solid content of the polyacrylic acid having a high molecular weight(A1) was 2.5wt%, when the solid content of the polyacrylic acid having a low molecular weight(A2) was 1 - 1.5wt%, the color was the best. And when the solid content of A1 and A2 was 1.5wt%, the degree of spreading was small and A1 was superior to A2 at the sharpness.

• Restorative Dentistry and Endodontics
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• 제14권2호
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• pp.5-19
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• 1989

The purpose of this study was to observe the microleakage of composite resin filling using several glass ionomer cements. The Class V cavities of eighty noncarious human molars were prepared at the cementoenamel juction on the facial and lingual surfaces of each tooth with a No.330 carbide bur in a high speed handpiece. The cavity dimensions were $3.0{\pm}0.5mm$ wide, $2.0{\pm}0.5mm$ high, and $1.5{\pm}0.5mm$ deep and all enamel cavosurface margins were beveled with a No.558 carbide bur in low speed handpiece. The bevel was approximately $45^{\circ}$ and 0.5-1.0mm in width. A total of the 160 cavities was divided into four groups, and then 144 cavities among them were three experimental groups and remaining sixteen cavities were control group. All of the prepared cavities were restored as follows: group 1 : Preparations were restored with there three glass ionomer cements. group 2 : Preparations were restored with a composite resin with three glass ionomer cement bases placed $0.2{\pm}0.1mm$ short of the cavosurface margin. group 3 : Preparations were restored with a composite resin with three glass ionomer cement bases extened to the cavosurface margin. group 4 : As control group, preparations were restored with a composite resin, PALFIQUE. The specimens were then thermocycled in a range of $6^{\circ}C-60^{\circ}C$ and immersed in a bath of 2.0% aqueous basic fuchsin solution for 24 hours. Dye penetration was read on a scale of 0 to 4 by Tani and Buonocore's method. The following conclusions were derived from the results obtained; 1. All groups showed significantly more leakage at the gingival margins than at the occlusal margins(p<0.0005). 2. At the gingival margins, group 1 showed less leakage than group 3(p<0.01) and group 4(p<0.0005), while group 3 exhibited less leakage than group 2(p<0.01) and group 4(p<0.0005). 3. At the occlusal margins, group 4 showed less leakage than group 3(p<0.1) and group 1(p<0.005), while group 3 exhibited less leakage than group 2(p>0.1) and group 1(p<0.025).