• Restorative Dentistry and Endodontics
• /
• v.31 no.3
• /
• pp.147-152
• /
• 2006

The purpose of this study was to evaluate the influence of the AH-26 root canal sealer on the shear bond strength of composite resin to dentin. One hundred and forty four (144) extracted, sound human molars were used. After embedding in a cylindrical mold, the occlusal part of the anatomical crown was cut away and trimmed in order to create a flat dentin surface. The teeth were randomly divided into three groups; the AH-26 sealer was applied to the AH-26 group, and zinc-oxide eugenol (ZOE) paste was applied to the ZOE group. The dentin surface of the control group did not receive any sealer. A mount jig was placed against the surface of the teeth and the One-step dentin bonding agent was applied after acid etching. Charisma composite resin was packed into the mold and light cured. After polymerization, the alignment tube and mold were removed and the specimens were placed in distilled water at $37^{\circ}C$ for twenty four hours. The shear bond strength was measured by an Instron testing machine. The data for each group were subjected to one-way ANOVA and Tukey's studentized rank test so as to make comparisons between the groups. The AH-26 group and the control group showed significantly higher shear bond strength than the ZOE group (p<0.05). There were no significant differences between the AH-26 group and the control one (p>0.05). Under the conditions of this study, the AH-26 root canal sealer did not seem to affect the shear bond strength of the composite resin to dentin while the ZOE sealer did. Therefore, there may be no decrease in bond strength when the composite resin core is built up immediately after a canal filling with AH-26 as a root canal sealer.

• Restorative Dentistry and Endodontics
• /
• v.32 no.1
• /
• pp.1-8
• /
• 2007

This study compared the microshear bond strength (${\mu}SBS$) of light-cured and dual-cured composites to enamel bonded with three self-etching adhesives. Crown segments of extracted human molars were cut mesiodistally, and 1 mm thickness of specimen was made. They were assigned to three groups by used adhesives: Xeno group (Xeno III), Adper group (Adper Prompt L-Pop), and AQ group (AQ Bond). Each adhesive was applied to cut enamel surface as per manufacturer's instruction. Light-cured (Filtek Z 250) or dual-cured composite (Luxacore) was bonded to enamel of each specimen using Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to ${\mu}SBS$ testing with a crosshead speed of 1 mm/minute. The mean ${\mu}SBS$ (n = 20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at the 0.05 probability level, The results of this study were as follows ; 1. The ${\mu}SBS$ of light-cured composite was significantly higher than that of dual-cured composite when same adhesive was applied to enamel. 2. For Z 250, the ${\mu}SBS$ of AQ group ($9.95{\pm}2.51 MPa$) to enamel was significantly higher than that of Adper soup ($6.74{\pm}1.80 MPa$), but not significantly different with Xeno group ($7.73{\pm}2.01 MPa$). 3. For Luxacore, the ${\mu}SBS$ of Xeno group ($5.19{\pm}1.32\;MPa$) to enamel was significantly higher than that of Adper group ($3.41{\pm}1.19\;MPa$), but not significantly different with AQ group ($4.50{\pm}0.96\;MPa$).

• Resources Recycling
• /
• v.15 no.4 s.72
• /
• pp.3-12
• /
• 2006

The feasibility for the employment of manganese nodule as an adsorbent for $SO_{2}$ gas has been investigated. The specific surface area of manganese nodule particle, which used in the experiments, was ca. $221.5m^{2}/g$ and the content of sulfur in manganese nodule was observed to significantly increase after $SO_{2}$ was adsorbed on it. The EPMA for the distilled water-washed and methanol-washed manganese nodule particle after $SO_{2}$ adsorption showed that its sulfur content was slightly decreased to 14.7% and 13.1% respectively, from 15.4% before washing. The XRD analysis of manganese nodule showed that todorokite and birnessite, which are manganese oxides, and quartz and anorthite were the major mineralogical components and weak $MnSO_{4}$ peaks were detected after $SO_{2}$ was adsorbed on manganese nodule. For an comparative investigation, limestone was also tested as an adsorbent for $SO_{2}$, however, no peaks for $CaSO_{4}$ were found by XRD analysis after the adsorption of $SO_{2}$. As the size of adsorbent increased, time for breakthrough was decreased and the adsorbed amount of $SO_{2}$ was also diminished. The $SO_{2}$ adsorption was hindered when its flow rate became high and the adsorption capacity of manganese nodule was observed to be superior to that of limestone. In addition, the mixture of manganese nodule and limestone did not show an increase in the adsorption of $SO_{2}$. Finally, as the temperature was raised, the adsorbed amount of adsorbate on manganese nodule was found to be decreased.

• Korean Journal of Heritage: History & Science
• /
• v.43 no.3
• /
• pp.242-281
• /
• 2010

There are a large number of Buddhist cultural relics in Mt. Namsan. The cultural relics carry the spirit of people of Shila who dream of Buddhist Elysium and the establishment of Buddhist nation. In the valley and the top of the mountain and on various rock cliff, stone statues of Buddha and stone pagodas stand in harmony with nature. For that reason, Mt. Namsan is called an open-air museum. And it played an important role in establishing 'The UNESCO World Heritage' status for Gyeongdju in December 2000. But sadly, there are many stone relics that have eroded away and damaged from collapsing in the passage of time. The seated stone statue of Buddha in Samreoung valley of Mt. Namsan is one of them. It was created between the 8th and 9th century, and restored without much care nor extensive historical research in 1923. As a result, The face of the Buddha remained with concrete mortar and its nimbus fallen backward and destroyed. Therefore, restoration and repair as well as creation of a statue environment for the statue were urgent. So we immediately started in restoration and repair. First, through the archaeological excavation around the stone Buddha, we carried the stone Buddha on the original position. In order to restore the statues to its original glory created by the Unified Shila Dynasty, we created a restoration plan in corporation with art historians and historians, then restored the jaw and the damage nimbus. Second, we made the weathering & damage map of the stone Buddha. In order to prevent second damage, we cleaned the surface of contaminants with distilled water. Third, we studied restoration method to prevent artificial damage. We recreated parts of his face and halo. Then each parts of the statue were restored to their original position. In the whole process of restoration, we tried to use traditional techniques.

• The Journal of the Convergence on Culture Technology
• /
• v.5 no.3
• /
• pp.271-282
• /
• 2019

This study was conducted to evaluate physiological activity of Robinia pseudo-acacia leaf and its skin penetration using polymer micelles and skin penetrating peptide. After extraction with Robinia pseudo-acacia using the ethanol and distilled water, various physiological activities were examined. The total concentration of polyphenol compounds was determined to be 47.42 mg/g (ethanol extract), 56.88 mg/g (hydrothermal extract) and DPPH radical scavenging ability at $1,000{\mu}g/mL$ was 44.24% in ethanol extract and it is higher than value(41.50%) in hydrothermal extract. The elastase inhibitory assay showed concentration dependence and elastase inhibition of Robinia pseudo acacia leaf ethanol extract was 54.09%, which was the highest at $500{\mu}g/mL$. In the SOD-like experiments, the concentration-dependent results were showed and the SOD-like activity of the Robinia pseudo-acacia leaf ethanol extract was higher than that of the Robinia pseudo acacia leaf hydrothermal extract at all concentrations. At a concentration of $500{\mu}g/mL$, Robinia pseudo acacia leaf ethanol extract showed the highest SOD-like activity of 76.41%. The tyrosinase inhibition at $20{\mu}g/mL$ was determined to be 56.47% (ethanol extract), 23.05% (hydrothermal extract). In the antimicrobial experiments, the hydrothermal extract had no effect, but ethanol extract represented maximum clear zone of 11.00 mm in Propionbacterium acnes strain and maximum clear zone of 10.50 mm. in Bacillus subtilis strain. To solve the problem of insolubility and to improve skin penetration, PCL-PEG polymer micelles containing Robinia pseudo-acacia leaf ethanol extracts and 1.0% cell permeable peptide, hexa-D-arginine (R6) were successfully prepared with particle size of 108.23 and 126.47 nm and excellent skin permeation effects could be showed.

• Journal of Bio-Environment Control
• /
• v.28 no.4
• /
• pp.404-410
• /
• 2019

This study was performed to investigate the seed morphological characteristics and dormancy type of Adenophora triphylla var. japonica Hara that high valued medicinal crop and to select the disinfectants and light quality for germination rate improvement. The seed disinfection was carried out using distilled water (control), NaClO 4%, $H_2O_2$ 4%, and benomyl $500mg{\cdot}L^{-1}$. The light quality treatments were set to dark condition (control I), fluorescent lamp (control II), LEDs [red, blue, green, and combined RB LEDs (red:blue = 8:2, 6:4, 4:6, 2:8)] with a photoperiod of 12/12 (light/dark) and light intensity $150{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density. Although the Adenophora triphylla var. japonica Hara seed was an underdeveloped embryo (E) and seed (S) with an embryo (E):seed (S) ratio of 0.4, it is germinated within 30 days, and seed moisture saturation was reached within 6 hours after immersion. After seed disinfection, the mold incidence rate was significantly inhibited, and the final germination rate was the highest at 87% in the benomyl seed disinfection. The final germination rate was the highest at 92% in the red light, and the mean daily germination was the lowest in the R2B8. Therefore, there is almost no dormancy in the Adenophora triphylla var. japonica Hara seed, and benomyl seed disinfectant and red light were effective in the improvement of germination rate. So it is considered to the high value of use for medicinal crop Adenophora triphylla var. japonica Hara cultivation.

• Journal of Bio-Environment Control
• /
• v.30 no.1
• /
• pp.37-45
• /
• 2021

This study was conducted to evaluate the growth characteristics, phenolic concentration and antioxidant capacity of safflower (Carthamus tinctorius L.) and amaranth (Amaranthus spp.) sprout and investigate the possibility of using super absorbent polymer (SAP) as a medium in hydroponic cultivation in a plant factory. The control was used a commercial sprout cultivation tool (19 × 14 × 9 cm, W × D × L), and a treatment (SAP) was added on the cultivation tool to compare the effect of SAP. Safflower sprouts were immersed in a distilled water at 30 ℃ for 5 hours, and then grown in a plant growth chamber. The temperature and relative humidity were maintained at 25 ± 1℃ and 70 ± 4%, respectively. The light condition was maintained at 35 ± 6 μmol·m-2·s-1 (12h). Amaranth sprouts were grown in a plant growth chamber maintained with temperature of 25 ± 2℃, relative humidity of 70 ± 5% and light condition of 188 ± 10 μmol·m-2·s-1 (16h). A physical and chemical characteristic of SAP, and a germination rate, growth characteristics and secondary metabolites were analyzed in both safflower and amaranth. There was no significant effect on SAP in a germination rate, growth and secondary metabolites of safflower compared to the control, whereas amaranth grown under SAP was higher in germination rate, dry weight, phenolic concentration, and antioxidant capacity compared to the control. As a result, this study was suggested that cultivation of sprouts using SAP would be possible in a plant factory, and further studies on SAP on plant physiological response are required.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.4
• /
• pp.467-475
• /
• 2021

The purpose of this study was to compare the effect of sodium fluoride(NaF) varnish and potassium iodide(KI) on remineralization efficacy of silver diamine fluoride(SDF) by measuring microhardness and evaluating surface morphology by scanning electron microscope(SEM). Artificial caries lesions were induced on extracted primary molars and vickers microhardness was measured. Specimens were randomly separated into 4 groups for treatment. The specimens in group I were treated with SDF, group II with NaF varnish after SDF, group III with KI after SDF and group IV with distilled water. After 8 days of pH cycling, vickers microhardness was measured and difference before and after treatment was calculated. For SEM, 2 samples were evaluated respectively after enamel polishing, lesion formation and after pH cycling. Group III showed highest increase in microhardness. Group I showed higher increase in microhardness than Group II but without statistical difference. Group IV showed lowest increase in microhardness value among 4 groups. On SEM image, group I, II and III showed smoother and less irregular surface compared to group IV. Amorphous crystal pellicles were observed in group III. In conclusion, SDF, SDF and NaF, SDF and KI groups showed smoother surface and increase in microhardness suggesting the possibility that remineralization effect might take place in oral conditions. In addition, in limited conditions of this study, applying NaF varnish after SDF did not increase the remineralization efficacy of SDF while KI significantly increased the remineralization efficacy of SDF. However, additional study considering various conditions that might affect demineralization and remineralization in clinical situations need to be conducted.

• Korean Journal of Poultry Science
• /
• v.49 no.4
• /
• pp.287-298
• /
• 2022

This study evaluated the efficacy of chlorine dioxide (ClO₂) as an oxidant to reduce malodor emission from chicken feces. Two experiments were performed with the following four treatments in parallel: 1) fresh chicken feces with only distilled water added as a control, 2) a commercial germicide as a positive control, and 3) 2,000 or 4) 3,000 ppm of ClO₂ supplementation. Aluminum gas bags containing chicken feces sealed with a silicone plug were used in both experiments, and each treatment was tested in triplicate. In Experiment 1, 10 mL of each additive was added on the first day of incubation, and malodor emissions were then assessed after 10 days of incubation. In Experiment 2, 1 mL of each additive was added daily during a 14-day incubation period. At the end of the incubation, gas production, malodor-causing substances (H₂S and NH₃ gases), dry matter, pH, volatile fatty acids (VFAs), and microbial enumeration were analyzed. Supplementing ClO₂ at 2,000 and 3,000 ppm significantly reduced the pH and the ammonia-N, total VFA, H₂S, and ammonia gas concentrations in chicken feces compared with the control feces (P<0.05). Additionally, microbial analysis indicated that the number of coliform bacteria was decrease after ClO₂ treatment (P<0.05). In conclusion, ClO₂ at 2,000 and 3,000 ppm was effective at reducing malodor emission from chicken feces. However, further studies are warranted to examine the effects of ClO₂ at various concentrations and the effects on malodor emission from a poultry farm.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.4
• /
• pp.379-391
• /
• 2022

The current study aimed to compare the pH, solubility value, and ion release capability of premixed mineral trioxide aggregates (MTAs) versus conventional pulp capping materials before and after setting. The following materials were used: resin-modified calcium silicate cement (TheraCal LC^®, TLC), resin-modified calcium hydroxide cement (Ultra-Blend^TM plus, UBP), and 2 kinds of premixed MTA (Endocem MTA^® premixed regular [EMPR] and Well-Root^TM PT [WRP]). The specimens of each material were prepared before and after setting and were immersed in distilled water. The materials' pH and solubility value were assessed. Next, three kinds of ion (calcium, sulfide, and strontium) released by pulp capping materials were evaluated via inductively coupled plasma atomic emission spectrometry. In the after-setting group, the pH of TLC and UBP decreased. However, the pH of the premixed MTAs increased with time. TLC released a higher concentration of strontium ion compared with the other materials. Meanwhile, EMPR released a significantly high concentration of sulfide ion (p < 0.05). In the after-setting group, the 2 kinds of premixed MTAs released a significantly higher concentration of calcium ion compared with the other materials (p < 0.05). In the after-setting group, EMPR had a significantly low solubility value (p < 0.05). The Kruskal-Wallis test, followed by the Mann-Whitney U test with Bonferroni correction, was used in statistical analysis. In conclusion, resin-modified calcium silicate cement, modified calcium hydroxide cement, and the 2 kinds of premixed MTAs had an alkaline pH and low solubility value and they released various concentrations of ions after setting.