• The Journal of Korean Academy of Prosthodontics
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• v.38 no.4
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• pp.427-437
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• 2000

Recently the 2nd generation laboratory composite resins were introduced. Although the mechanical properties of these composite resins have been improved, there were some disadvantages such as discoloration, low abrasion resistance and debonding between metal and resin. The purpose of this study was to evaluate the tensile bond strength between non-pecious dental alloy(verabond) and four veneering reinforced composite resins ; Targis(Ivoclar Co., U.S.A.), Artglass(Kulzer CO., Germany), Sculpture(Jeneric Pentron Co., U.S.A.), and Estonia(Kurary Co., Japan). All test metal specimens were polished with #1,000 SiC paper, and sandblasted with $250{\mu}m$ aluminum oxide. After then. according to manufacturer's instructions metal adhesive primer and veneering resins were applied. All test specimens were divided into two groups. One group was dried in a desiccator at $25^{\circ}C$ for 3 days, the other group was subjected to thermal cycling($2,000{\times}$) in water($5/55^{\circ}C$). Tensile bond strength was measured using Instron Universal Testing machine and the fractured surface was examined under the naked eyes and scanning electron microscope. Within the limitations imposed in this study, the following conclusions can be drawn: 1. In no-thermal cycling groups, there were no significant differences between Estenia and VMK68 but there were significant differences between Targis, Artglass, Sculpture and VMK68(p<0.05). 2. In no-thermal cycling resin groups, the highest tensile bond strength was observed in Estenia and there were significant differences between Estenia and the other resins(p<0.05). 3. Before and after thermal cycling, there were significant differences in tensile bond strength of Targis and Artglass(p<0.05). The tensile bond strength of Artglass was decreased and that of Targis was increased. 4. In no-thermal cycling groups, Artglass showed mixed fracture modes(95%), but after thermal cycling, Artglass showed adhesive fracture modes(75%).

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.3
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• pp.101-110
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• 2021

Purpose: In this study, we intended to study the change in bond strength according to the thermal cycling of provisional resin and 3D printed resin for making provisional restoration. Materials and Methods: Through DLP method, 3D printed resin powder was used to produce 3D printed resin samples. The samples were grouped into eight groups, according to types of provisional resin (PMMA, bis-acryl resin) which is to be bonded on the samples and numbers of thermal cycling (control, 2,000, 3,000, 5,000 cycles). Shear bond strength of the bonded samples was measured on the universal testing machine. Results: As the number of thermal cycling increased, the shear bond strength of PMMA and bis-acryl resin for 3D printed resins decreased except between 3,000 cycles and 5,000 cycles in PMMA groups. In the PMMA group, there were significant differences in shear bond strength between less number than 3,000 cycles (P < 0.05) and no significant differences between more number than 3,000 cycles (P > 0.05). In the bis-acryl resin group, there were significant differences in shear bond strength between control and 2,000 cycles, control and 3,000 cycles, and control and 5,000 cycles (P < 0.05), no significant difference between 2,000 and 3,000 cycles, between 3,000 and 5,000 cycles (P > 0.05). Conclusion: The shear bond strength between 3D printed resin and provisional resin tended to decrease after thermal cycling.

• Journal of Ginseng Research
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• v.43 no.4
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• pp.580-588
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• 2019

Background: Ginsenoside Rg1 has been shown to clear senescence-associated beta-galactosidase (SA-${\beta}$-gal) in cultured cells. It remains unknown whether Rg1 can influence SA-${\beta}$-gal in exercising human skeletal muscle. Methods: To examine SA-${\beta}$-gal change, 12 young men (age $21{\pm}0.2years$) were enrolled in a randomized double-blind placebo controlled crossover study, under two occasions: placebo (PLA) and Rg1 (5 mg) supplementations 1 h prior to a high-intensity cycling (70% $VO_{2max}$). Muscle samples were collected by multiple biopsies before and after cycling exercise (0 h and 3 h). To avoid potential effect of muscle biopsy on performance assessment, cycling time to exhaustion test (80% $VO_{2max}$) was conducted on another 12 participants (age $23{\pm}0.5years$) with the same experimental design. Results: No changes of SA-${\beta}$-gal were observed after cycling in the PLA trial. On the contrary, nine of the 12 participants showed complete elimination of SA-${\beta}$-gal in exercised muscle after cycling in the Rg1 trial (p < 0.05). Increases in apoptotic DNA fragmentation (PLA: +87% vs. Rg1: +133%, p < 0.05) and $CD68^+$ (PLA:+78% vs. Rg1:+121%, p = 0.17) occurred immediately after cycling in both trials. During the 3-h recovery, reverses in apoptotic nuclei content (PLA:+5% vs. Rg1 -32%, p < 0.01) and increases in inducible nitrate oxide synthase and interleukin 6 mRNA levels of exercised muscle were observed only in the Rg1 trial (p < 0.01). Conclusion: Rg1 supplementation effectively eliminates senescent cells in exercising human skeletal muscle and improves high-intensity endurance performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.981-982
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1477-1478
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.997-998
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1415-1416
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• 2013

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.1-5
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• 2005

An experimental study was conducted to develop an understanding of failure of ceramic coating when subjected to a thermal cycling. Number of cycles to failure were decreased as the coating thickness and the oxide of bond coat were increased. Using the finite element method, an analysis of stress distribution in ceramic coatings was performed. Radial compressive stress was increased in the top/bond coat interface with increasing coating thickness and oxide of bond coat.

• Journal of the Korean Magnetic Resonance Society
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• v.21 no.4
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• pp.131-134
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• 2017

Proton detected Heteronuclear Multiple Quantum Coherence (HMQC) and Heteronuclear Single Quantum Coherence (HSQC) essentially provide the same information - correlation of the chemical shift of the proton to J-coupled hetero nuclei such as $^{13}C$ or $^{15}N$ nuclei. This paper is a practical note for the students who ask which one is better and which methods they use routinely. Artifact suppression using phase cycling and gradient pulses are discussed.

• The monthly packaging world
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• s.249
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• pp.70-78
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• 2014