• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.80-88
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• 2003

Object The purpose of this study were to evaluate the microtensile bond strength of resin fiber reinforced post to radicular dentin using resin cement according to various dentin surface treatment and to observe the inter face between post and root dentin under SEM Material and Method A total 16 extracted human single rooted teeth were used. A lingual access was made using a #245 carbide bur in a high-speed handpiece with copious air water spray. The post space was mechanically enlarged using H-file(up to #60) and Gates Glidden bures(#3). This was followed by refining of the canal space using the calbrating drill set provided in ER Dentinpost(GEBR, BRASSELER GmbH&Co. KG). The 16 teeth were randomly distributed into 4 group of 4 teeth. Group 1 teeth had their post space prepared using 10% phosphoric acid as root canal surface treatment agent during 20s. The canal was then rinsed with saline and dried with paper point. Group 2 teeth had their post space prepared using 3% NaOCl as root canal surface treatment agent during 30min. The canal was then rinsed with saline and dried with paper point. Group 3 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. The canal was then rinsed with saline and dried with paper point. Group 4 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. After rinsing with saline, the canal was rinced 10m1 of 3% NaOCl for 30min. After drying with paper point, the post(ER Dentinpost, GEBR, BRASSELER GmbH&Co. KG) was placed in the treated canals using resin cement. Once the canal was filled with resin cement(Super bond C&B sunmedical co. Ltd.), a lentulo was inserted to the depth of the canal to ensure proper coating of the root canal wall. After 24 hours, acrylic resin blocks($10{\cdot}10{\cdot}50mm$) were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strengths for each stick was measured with Microtensile Tester. Failure pattern of the specimen at the interface between post and dentin were observed under SEM. Results 1. Tensile bond strengths(meen{\pm}SD$) ) were expressed with ascending order as follows group 4, $12.52{\pm}6.60$ ; group 1, $7.63{\pm}5.83$ ; group 2, $4.13{\pm}2.31$ ; group 3, $3.31{\pm}1.44$. 2. Tensile bond strengths of Group 4 treated with 17% EDTA +3%NaOCl were significant higher than those of group 1, 2 and 3 (p<0.05). 3. Tensile bond strengths of Group 1 treated with 10% phosphoric acid were significant higher than those of group 2 (p<0.05). Tensile bond strengths of Group 4 treated with 17% EDTA +3% NaOCl was significant higher than those of other groups.

• Journal of the Korean Society of Clothing and Textiles
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• v.5 no.1
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• pp.9-14
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• 1981

The influence of laundering conditions on calcium deposition on the fabric was studied by repeated laundering the cotton fabric with soap in the hard water of 200 P.P.M. $CaCO_3$. The experimental variables were: 1) soap concentrations ($0.06\%$, $0.13\%$, $0.25\%$), 2) water contents in the fabric after hydroextraction. ($65\%$, $150\%$, $315\%$), 3) builders (Na-EDTA, sodium carbonate, sodium metasilicate), 4) washing cycle (5, 10, 15, 20 cycles). The fabric was washed for 15 minutes at $23\pm1^{\circ}C$ in a washing machine (Model; Gold Star Wp-2005) under the similar conditions with those of home laundering, and rinsed 5 times for 5 minutes. The amount of calcium deposits on the fabric was determined by the EDTA-Back titration method described by Wasserman and Basch. Results of this study were follows: 1) The amount of calcium deposits on the fabric increased with increasing wash cycles. 2) During the rinsing process, residual calcium content on the fabric increased with water content in the fabric after hydroextraction. 3) The amount of calcium deposits on the fabric decreased with the increasing soap concentration above the equivalent amount of calcium ion content in the water. 4) Sequestering agents and alkaline builders influenced the amount of calcium deposits on the fabric. The amount of calcium deposits on the fabric was in the order of sodium metasilicate, sodium carbonate, nonbuilder, and EDTA.

• Conservation Science in Museum
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• v.9
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• pp.31-49
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• 2008

We have investigated and conserved three small Buddha statues dating from Joseon period that were purchased by the National Museum of Korea. Chemical analysis and investigation of internal structures were enabled us to identify its compositions and hollow spaces which have various materials just like fabrics, silver ornaments, beads and wood fragments. The fabrics date from the early years of the Joseon dynasty to the middle one. The compositions of matrix of the Buddha statues vary 80-90 wt% Ag and 7-15 wt% Cu. And its surface layers were gilt with amalgam. Mechanical and chemical cleaning with EDTA-2Na were applied together during the cleaning process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.3
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• pp.348-355
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• 1989

This experiment was conducted to investigate the characteristics of alkaline protease from Aspergillus fumigatus which was isolated from soil as a superior strain for the production of the alkaline protease. The optimum temperature for enzyme activity was $50^{\circ}C$ and optimum pH was 9.0. The enzyme was stable at pH 8.0 to 10.0 and thermal inactivation was shown $30^{\circ}C$. The activity of the enzyme was increased by the addition of $Mn^{++},\;Cu^{++},\;Ba^{++},\;Mg^{++},\;$wheras it was inhibitied by $K^+,\;Fe^{+++},\;Ag^+,\;Pb^{++},\;Na^+,\;Ca^{++},\;Hg^+,\;Zn^{++}$. EDTA. 2, 4-DNP, ${\varepsilon}-amino$ caproic acid did not show inhibitory effect on the proteolytic activity of alkaline protease but P-chloromercuribenzoic acid inhibited the enzyme activity, indicating that reactive sulfhydryl group is required for the enzymatic activity. The reaction of this enzyme followed typical Michael-Menten Kinetics with the Km value of $8.33{\times}10^{-4}mole/{\ell}$ with the Vmax of $47.62{\mu}g/min$. This enzyme had stronger proteolytic activity than trypsin on substrate such as casin and hemoglibin.

• Korean Journal of Microbiology
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• v.24 no.1
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• pp.24-31
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• 1986

The optimal conditions for the formation and the regeneration of Pseudomonas spheroplast were measured. Pseudomonas spp. cells were transformed to spheroplasts from 99.0% to 99.9% by treatment of $100{\mu}g/ml$ lysozyme and 10mM EDTA at room temperature. The optimal pH for the spheroplast formation was pH 8.0. Magnecium chloride, calcium chloride and streptomycin were effective on the stabilization of Pseudomonas spheroplast, while $Mg^+\;and\;Na^+$ ions were effective on the formation of Pseudonomas spheroplast. Rich Regeneration Medium was used for the regeneration of Pseudonomas spheroplast. To improve regeneration frequency, Bovin Serum Albumine and cationic ions were added to the spheroplast dilution beffer and regeneration environment respectively. Treatment of 20mM calcium chloride in ehr Rich Regeneration Medium could improve the yield of regenerants as much as 28-fold. Treatment of 1% Bovin Serum Albumine in the spgeroplast formation and dilution buffer increased the yield of regenerants to 10-fold. Also, the regeneration frequency was improved to 14-fold shen Rich Regeneration Meidum containing 0.5% Gelatin was used for regeneration as well as 1% Bovin Serum Albumine.

• Restorative Dentistry and Endodontics
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• v.49 no.3
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• pp.25.1-25.9
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• 2024

Objectives: This study aimed to evaluate the color stability and solubility of Biodentine and NeoPutty in contact with different irrigation solutions. Materials and Methods: Biodentine and NeoPutty were set in cylindrical molds with 7 mm diameter and 1.5 mm high and immersed in distilled water, 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), 9% 1-hydroxyethylidene 1,1-diphosphonate (HEDP), and 5% sodium hypochlorite (NaOCl) solutions for 24 hours. The color change was measured with a spectrophotometer. The solubility values were calculated as the mass loss was expressed as a percentage of the original mass using an analytical balance with 10^-4 g accuracy. Data were analyzed with Kruskal-Wallis followed by Mann-Whitney U tests, and 2-way analysis of variance test followed by Bonferroni corrections for pairwise comparisons for solubility and color stability with a 5% significance threshold, respectively. Results: Biodentine exhibited higher color changes compared to the NeoPutty contact with all solutions except distilled water (p < 0.05). Both hydraulic cements (HCs) showed higher discoloration values immersion in CHX followed by NaOCl. No statistically significant difference was found between Biodentine and NeoPutty regardless of irrigation solution in terms of solubility (p > 0.05). Solubility values were lower in the distilled water group compared to EDTA and CHX (p < 0.05). Conclusions: Tested HCs showed solubility and color changes at various rates. NeoPutty could be an appropriate material in aesthetic areas. The usage of HEDP as an irrigant solution can be considered suitable for various endodontic treatments due to its relatively lower solubility and discoloration values.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.5
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• pp.922-932
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• 1997

Blue jeans are finished with stonewashing process to give it optimal softness and color contrast of blue and white. So, Yellowing may well be generated during storage or use and thereby, their appearance may be damaged much. So, this study was aimed at finding the solutions to reduce the yellowing problem caused by residual metals after stonewshing. To this end, sample blue jeans were made to be finished with various methods of wet-treatment and then, be subject to daylight to check their photoyellowing. The results of this test can be summarized as follows; Since the stonewashing process was found to affect the yellowing, the residual metals of stone- washed blue jeans was analyzed. And it was found that it contained such residual metal as Al, Ca, Cu, Ti, Si, K and Zn. In particular, it was conceived that Al was a prime cause affecting the yellowing. Meanwhile, when the blue jeans were treated by the metal ionchelating agent of EDTA-2Na, the residual levels of Al and Ti were reduced by about 50%, while the photoyellolving was lowered by 75%, which is suggesed that EDTA is very effective in preventing the yellowing. On the other hand, when the blue jeans were bleached by the hypochlorite, chlorine remained in blue jean accelerated the yellowing. However, when this blue jean was treated again by the sodium thiosulfate for its dechloridization, the residual of chlorine was reduced, and the yellowing was lowered by about 43%.

• Analytical Science and Technology
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• v.8 no.2
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• pp.215-220
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• 1995

A simple, efficient and sensitive method was described for the simultaneous determination of catecholamine, indoleamine and related metabolites from the homogenates of the rat brain striatum by HPLC-ECD. The optimum mobile phase on a reverse phase $C_{18}$ column was 35mM sodium acetate buffer(included 10mM citric acid, 0.13mM $Na_4EDTA$, 0.58mM SOS, pH3-4):MeOH=85:15. The column temperature was $30^{\circ}C$. Dopamine(DA), 3, 4-dihydroxyphenyl acetic acid(DOPAC), homovanilic acid(HVA), 5-hydroxyindole acetic acid(5-HIAA), serotonin(5-HT) and noradrenaline(NA) could be separated and analysed to very small amount. The detection limits of this method were 2~10pg per injection for all components. The effects of age and sex of rat on the contents of the catecholamines and their metabolites in rat brain striatum were studied. The levels of DA and 5-HT contents of the 7 week old female rats were higher than those of the 7 week old male rats. As the age of rat increases, the contents of DOPAC increased significantly.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.1
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• pp.16-22
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• 2024

The conventional degreasing process involves removing oil and contaminants at temperatures above 80℃, resulting in excessive energy consumption, increased process costs, and environmental issues. In this study, we aimed to find the optimal degreasing conditions for the pre-treatment process of electro-galvanizing cold-rolled steel sheets, conducted efficiently at room temperature without the need for a separate heating device. To achieve this, we developed a room temperature degreasing solution and a brush-type degreasing tool, aiming to reduce energy consumption and normalize the decrease in degreasing efficiency caused by temperature reduction. Alkaline degreasing solution were prepared using KOH, SiO₂, NaOH, Na₂CO₃, and Sodium Lauryl Sulfate, with KOH and NaOH as the main components. To enhance the degreasing performance at room temperature, we manufactured additives including sodium oleate, sodium stearate, sodium palmitate, sodium lauryl sulfate, ammonium lauryl sulfate, silicone emulsion, and EDTA-Na. Room temperature additives were added to the alkaline degreasing solution in quantities ranging from 0.1 to 20 wt.%, and the uniformity of degreasing and the adhesion of the galvanized layer were evaluated through Dyne Test, T-bending Test, OM, SEM, and EDS analyses. The results indicated that the optimal degreasing solution composition consisted of NaOH (30 g/L), Na₂CO₃ (30 g/L), SLS (6 g/L), and room temperature additives (≤1 wt%).

• Journal of Environmental Science International
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• v.21 no.3
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• pp.369-375
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• 2012

We investigated usefulness of chicken feather as bioadsorbent for removal of hexavalent chromium[Cr(VI)] and oil from aqueous solution. Chicken feather was chemically treated with DTPA, EDTA, NaOH and SDS, respectively. Among them, EDTA was the most effective in adsorbing Cr(VI). Cr(VI) uptake by chicken feather was increased with decreasing pH; the highest Cr(VI) uptake was observed at pH 2.0. By increasing Cr(VI) concentration, Cr(VI) uptake was increased, and maximum Cr(VI) uptake was 0.34 mmol/g. Cr(VI) adsorption by chicken feather was well described by Freundlich isotherm than Langmuir isotherm and Freundlich constant(1/n) was 0.476. As the concentration of chicken feather was increased, Cr (VI) removal efficiency was increased but Cr(VI) uptake was decreased. Most of Cr(VI) was adsorbed at early reaction stage(1 h) and adsorption equilibrium was established at 5 h. On the other hand, chicken feather adsorbed effectively oils including bunker-A and bunker-C. In conclusion, our results suggest that chicken feather waste could be used to remove heavy metal and oil; it is a potential candidate for biosorption material.