• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.374-382
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• 2001

The purpose of this study was to investigate the surface morphology and measure shear bond strength of Er : YAG lased enamel. To determine the most effective energy density of laser for improving bonding strength of human enamel, 24 specimen were lased from 30mJ to 150mJ at 1Hz used focused, defocused beam. After irradiation, the lased specimen were observed scanning electron microscope. To determine the resin shear bond strength of Er : YAG lased enamel, the 90 specimen were divided into 3 groups. The Control group was etched with 37% phosphoric acid for 15seconds and rinsed. Group 1 was only laser irradiaton(60mJ, 10Hz), Group 2 was irradiated as Group 1 regimen, followed 37% phosphoric acid etching. The following results were obtained: 1. In both focused and defocused Er : YAG lased enamel surface are similar to acid-etched enamel more than 60mJ in SEM evaluation. 2. The more increased laser energy, the more observed fissuring surface. 3. The highest mean shear bond strength value was observed in control group with the statistical significance(p<0.05) between all the other groups and the shear bond strength in group 1 was the lowest with significant difference among the other groups.

• Restorative Dentistry and Endodontics
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• v.34 no.3
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• pp.223-231
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• 2009

The purpose of this study was to evaluate the effect of a desensitizer on dentinal bond strength in cementation of composite resin inlay. Fifty four molar teeth were exposed the occlusal dentin. Class I inlay cavities were prepared and randomly divided into six groups. Control group: no agent, Group 1 : Isodan, Group 2 : One-step, Group 3 : All-Bond SE, Group 4 : Isodan + One-step, Group 5 : Isodan + All-Bond SE. Desensitizing agent and dentin bonding agents were applied immediately after the completion of the preparations. Impressions were then made. The composite resin inlays (Tescera, Bisco) were fabricated according to the manufacturers' guidelines. Cementation procedures followed a standard protocol by using resin cement (Bis-Cem, Bisco). Specimens were stored in distilled water at $37^{\circ}C$ for 24 hours. All specimens were sectioned to obtained sticks with $1.0{\times}1.0\;mm^2$ cross sectional area. The microtensile bond strength (${\mu}TBS$) was tested at crosshead speed of 1 mm/min. The data was analyzed using one way ANOVA and Tukey's test. Scanning electron microscopy analysis was made to examine the details of the bonding interface, 1. Group 1 showed significantly lower ${\mu}TBS$ than other groups (p<0.05). 2. There was no significant difference between the ${\mu}TBS$ of Group 3 and Group 5. 3. The ${\mu}TBS$ of Group 4 showed significantly lower than that of Group 2 (p<0.05). In conclusion, a desensitizer (Isodan) might have an adverse effect on the bond strength of composite resin inlay to dentin.

• Polymer(Korea)
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• v.39 no.2
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• pp.240-246
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• 2015

Formation of a strong 3-dimensional interfacial network structure via chemical reaction between hydroxyl group on silica surface and NR chain by the addition of bis(triethoxysilylpropyl)tetrasulfide (TESPT) into silica-filled NR compound was observed by using Py-GC/MS and SEM. Addition of TESPT into silica-filled NR compound decreased scorch time ($t_{10}$) due to increased sulfur content, and reduced cure rate index (CRI) via continuous reaction between sulfur atoms in TESPT, which acted as a sulfur donor, and activators and/or accelerators. Addition of TESPT in the compound improved processability and mechanical properties of the compound. Overall, we observed that the addition of TESPT into the silica-filled NR compound formed a silica-TESPT-NR network, and thus the degree of crosslinking was increased resulting in improved mechanical properties.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.217-225
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• 2002

When we use the flowable resin on the primary molars for quick handling, one of the most important property is the wear resistance. This study was performed to compare the wear resistance characteristics of four flowable composite resins [Arabesk flow (group 1), Tetric flow (group 2), Aeliteflow (group 3), Filtek flow (group 4)] to that of one control composite resin [Z100 (group 5)]. Specimen discs(n=10), 10mm wide and 2mm thick, were stored in distilled water at $37^{\circ}C$ for 7 days prior to testing. The specimens were subjected to 50,000 strokes at 2 Hz on the MTS system. During the test, the following parameters were maintained: the lateral excursion at 0.4mm, occlusal force at 2-100N with a force profile in the form of a half sine wave. The measurements of volume loss, depth of wear, and Vicker's hardness number of composite resins, and SEM observations of the polished and abraded surfaces were established. One-way ANOVA and Scheffe's multiple comparison test were employed to detect statistically significant differences among the flowable composite resin groups and the control composite group at P<.05. The following results were obtained: 1. Group 3 showed the least volume loss, while group 4 showed the greatest. The mean volume loss increased in the following order: group 3

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.440-447
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• 2009

This study was performed to compare the wear resistance of sealant and flowable resins for analyzing the effect of flowable resin as a sealant in preventive resin restorations. Specimens were made and Vicker's hardness number and surface roughness were measured. SEM observations of the polished and abraded surfaces were established. Kruskal-Wallis rank test and Mann-Whitney U test at the significant level of ${\alpha}$=0.05 were used. The following results were obtained: 1. The microhardness was decreased among groups in following order: Z350 (3M ESPE, U.S.A), Estelite (Tokuyama Dental, Japan) and Ultraseal (Ultradent, U.S.A). There were significant differences in all groups (p<0.0001). 2. The surface roughness was decreased among groups in following order: Ultraseal XT plus, Palfique Estelite LV and Filtek Z350 flowable. However, there is no statistically significant differences in roughness among Estellite, Z350 and Ultraseal at the significance level of ${\alpha}$=0.05, with p=0.116 3. SEM observation of the unworn and worn surfaces revealed the qualitative differences in the wear appearance among groups. The results in this study indicate that flowable resin is better than sealant in aspect of physical properties.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.111-118
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• 1992

The curing acceleration of epoxy/amine system was investigated by using differential scanning calorimeter(DSC), The epoxy, diglycidylether of bisphenol A (DGEBA) was cured with methylene dianiline (MDA) with or without accelerators. Two kinds of accelerators were tested for the study ; tris(dimethylaminomethyl)phenol (DMP - 30) and 3 - (3,4 - dichlorophenyl)-1, 1-dimethylurea (DIURON). Heats of reaction and glass transition temperatures ($T_g$) of the cured epoxy system were analyzed by DSC along with the estimation of activation energy by the dynamic DSC studies. It was found that DMP - 30 is more effective accelerator than DIURON which showed faster curing and lower activation energy.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.283-292
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• 2016

The purpose of this study was to explore the cultural perspectives and experiences relating to insulin therapy among the diabetes. The authors conducted four semi-structured focus groups and individual interviews with 19 adults with type 1 and 2 diabetes, focusing on the personal experiences and thoughts regarding insulin therapy. Patients' perspectives and experiences relating to taking insulin formed three categories of themes: preoccupations about insulin, barriers to taking insulin, and benefits to taking insulin. The theme for preoccupations about insulin was "vague fear," while the theme of barriers to taking insulin were "worrisome insulin-related issues", "ambivalent feelings (trust/mistrust) about healthcare providers," "dependent life," "feeling about supporters(family, friends, and religion)," "inconvenience," "regret about the past," and "embarrassment." The theme of benefits to taking insulin were "recognition" and "physical recovery and confidence in regulating blood glucose". Based on this study, patients' feelings about their insulin should be respected by healthcare providers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.323-332
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• 2021

This study was undertaken to develop a new combination tablet containing silodosin and solifenacin succinate for treating urination disorders, for which a simultaneous analytical method of silodosin and solifenacin succinate was established. The aqueous solubility of silodosin and solifenacin succinate was determined to be higher than 1 mg/ml in various buffers, and dissolution of the silodosin and solifenacin succinate commercial products was accomplished within 30 minutes. The drug-excipients compatibility test was subsequently evaluated using differential scanning calorimetry. Excipients without compatibility were selected, and various combination formulations were prepared applying the wet granulation method. Of these, the formulation comprising silodosin, solifenacin succinate, lactose hydrate, MCC PH101, sodium lauryl sulfate (SLS), Povidone K30, crospovidone and magnesium stearate, having a weight ratio of 8/10/56/112/2/6/6/2, respectively, showed equivalence comparative to the dissolution achieved with the commercial products of silodosin (Thrupas tab) and solifenacin succinate (Vesicare tab). Thus, we propose that compared to the currently available commercial products, this novel combination tablet containing silodosin and solifenacin succinate is an effective alternative for the treatment of urination disorders.

• Journal of Life Science
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• v.28 no.1
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• pp.90-98
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• 2018

Eggshell (ES) is a by-product of table eggs with high content of calcium carbonate which can be used as a calcium source in feed. In this study, we have first illuminated the potential application of ES as a novel carrier for probiotics. The carriers used in the study include a SBM (Soybean meal), ESL (Eggshell powder with large particles), ESF (Eggshell powder with fine particles), and the complex carriers (SBM+ESL, SBM+ESF). The structure of carriers absorbed by L. plantarum was confirmed by SEM image. Among these carriers, the complex carrier SBM+ESF showed the highest viability of L. plantarum with pH 7~8 during four weeks storage at room temperature. The SBM+ESF was further tested as a carrier for various probiotic strains at $4^{\circ}C$ or $30^{\circ}C$. All the probiotic strains showed high viability at $4^{\circ}C$ storage. However, a significant reduction of Lactobacillus cells was observed at $30^{\circ}C$ storage. B. lichenifomis maintained high viability whereas B. subtilis, B. amyloliquefaciens, and S. cerevisiae showed the reduction of $2{\log}_{10}$ (CFU/g). These results suggest that if the ESF as a calcium source in feed was mixed with SBM, it can be used as an effective complex carrier for improving the viability of some probiotics including B. licheniformis.

• Polymer(Korea)
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• v.28 no.6
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• pp.551-555
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• 2004

Cellulose diacetate (CDA) nanocomposite films were prepared by using various plasticizer and montmorillonite nanofiller in methylene chloride/ethanol (9:1 w/w) mixed solution. The thermal property (T$_{g}$) of prepared CDA films was observed by DSC and T$_{g}$ of the films was decreased with the increase in the plasticizer content. The degree of dispersion of MMT in the CDA film was observed by XRD and mechanical property of CDA film was measured by tensile strength and Young's modulus. When the plasticizer was added into the CDA film upto 30 wt%, the Young's modulus of film was decreased from 1930 MPa to 1131 MPa but was increased from 1731 MPa to 2272 MPa when the MMT was added into the film upto 7 wt%. The mechanical properties of CDA films were decreased by addition of plasticizer but strengthened by the incorporation of MMT.