• Journal of Animal Environmental Science
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• v.11 no.3
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• pp.161-168
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• 2005

The disinfectants are important to prevention of infectious diseases for livestock and have been used widespreadly in recent years. This study was conducted to determine the effect of the disinfectants on microorganisms with reference to disinfectants concentration and application period in piggery slurry. As material, chemically different four disinfectants were used and no disinfectant, as control. These four disinfectants were Acids, Basic, Aldehydes and Alkalis, respectively. The characteristics pH, moisture content and organic matter of the piggery slurry used in this study were 8.2, $98.6\%,\;0.4\%$, respectively. The initial total microorganisms of piggery slurry were $6.3\times10^5$ cfu/ml, and Escherichia coli, Staphylococcus aureus, Bacillus cereus were $1.2\times10^4,\;4.1\times10^4,\;1.7\times10^4 cfu/ml,$ respectively. The disinfectants were applied at $100\%,\;200\%\;and\;300\%$ concentrations on the piggery slurry surface. It was determined that the effect of disinfectants varied accordance to concentration and application time. The most sensitive microorganisms were Escherichia coli and Staphylococcus aureus, while Bacillus cereus was found to be durable. As a result of this study, the microorganinsms of the piggery slurry are on the decrease by all disinfectants during 2 weeks, but showed a tendency to increase in number after that time. Accordingly, the microorganisms which are concerned in the liquid composting of piggery slurry were not affected by the disinfectant after 2 weeks.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.263-268
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• 2009

The Yellow Sea is extremely important to the economy and to the health and well-being of surrounding countries, Korea and China. Recently, the Yellow Sea is under constantly increasing threat of degradation due to the increase of environmental pollution and over-fishing. The governments of Korea and China have been aware of the importance of the Yellow Sea and reached an Environmental Agreement between Korea and China at the governmental level(November, 1993) According to this environmental agreement the Yellow Sea Environmental Cooperative Research between Korea and China has been undertaken since 1997. The joint cruise had been conducted once a year at 33 stations in the 4 lines of the Yellow Sea where the 9 stations of the D line was newly added in the 7th cruise in 2003. The samples were analyzed by scientists of both countries at the WSFRI, Korea and the OEMNC of the SEPA, China in turn, the annual report has been published every year during 1998-2008. The scientific efforts to fix the cruise time in October and to extend research frequency, as twice a year, should be considered, and this requires the governmental supports such as research funds and other related administrational assistance on both sides. Finally, scientists should also pay a concentrated attention to standardize the analytical methods including quality control and to improve this Yellow Sea research as one of the most representative international projects in the Yellow Sea where sharing additional informations available, if exist of dumping sites and material content, and of the freshwater quality will be of great help to broaden the output of this joint research project.

• Journal of the Korean Society of Food Science and Nutrition
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• v.10 no.1
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• pp.93-101
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• 1981

This study is designed to investigate the properties of caramel color made by corn sugar molasses, a new material. Com sugar refined and then caramelized in the solution of pH 2-10 ranges using catalysts such as ammonium carbonate, glycine and lysine. The control solution are 10% hydrochloric acid and sodium carbonate. The result were as follow; The caramelization showed the intensity of very strong color when added 0.4% ammonium carbonate as a catalyst. Color hue appeared to have the same color hue of the yellow belt and the red belt when compared with standard color hue in alkali, but the samples blue belt in all pH ranges showed a strong color hue than the standard color hue. Also, the stability of tannin, table salt and alcohol was transparent in all pH ranges, but the stability of acid appeared hazy at pH 9-10. In the case of glycine as a catalyst, caramelization showed the intensity of strong color when added 0.8% glycine at pH 9. Color hue showed in the yellow belt, strong in the red belt and very strong in the blue belt in all pH ranges when compared with standard color hue. Stability of tannin, table salt, acid alcohol was quite stable. In the case of lysine as a catalyst, caramelization showed strong color intensity when added 0.4% lysine in pH 9. Stability of tannin, table salt, acid and alcohol was quite stable.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.813-823
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• 1998

The frictional force has been considered as an harmful factor in an active unit where tooth movement occurs, but as an advantageous factor in anchor unit that resist tooth movement. That is, efficient tooth movement is planned by using ligation methods that have low levels of bracket-wire frictional force and the anchorage control can be achieved by using ligation methods that have high levels of bracket-wire frictional force that result in binding of the bracket accompanied by little or no tooth movement. The purpose of this study was to evaluate the frictional force generated between bracket and wire in accordance with the methods of ligation, the material of ligation and the passage of time under artificial saliva. Tested were 0.017x0.022 inch stainless steel wires in standard edgewise twin brackets for upper central incisors in a 0.018-inch slot. The wires were ligated into the brackets with elastomeric modules and stainless steel ligatures. Whole tie, half tie, twisting tie and double overlay tie were done with elastomeric modules. With 0.009-inch stainless steel ligature whole tie and half tie were done by needle holder and whole tie by ligature tying plier. With 0.012-inch stainless steel ligature whole ties were done by needle holder. Whole tie groups of elastomeric module were kept in artificial saliva bath at $37^{\circ}C$ for 28 days. The frictional force was recorded by means of an Instron universial testing instrument (4202 INSTRON, Instron Co., U.S.A.) at initial, 7, 14, 21, and 28 days. The results for ligated samples in a simulated oral environment revealed the fellowing : ${\cdot}$In elastomeric module whole tie, 28 days group was significantly greater mean static frictional force than any other group but there were no significant differences among any other group (p>0.05). ${\cdot}$Elastomeric module twisting ties were significantly greater mean static frictional forces than any other ligation method but there were no significant differences between twisting tie and double overlay tie (p>0.05). Twisting tie, double overlay tie, whole tie, half tie showed differences in decreasing order. ${\cdot}$Stainless steel half tie produced lower mean static frictional force than whole tie, ligation by ligature tying plier produced greater mean static frictional force than by needle holder and ligation with 0.012-inch stainless steel ligature produced greater mean static frictional force than with 0.009-inch stainless steel ligature (p<0.05). ${\cdot}$There were no significant differences between the mean static frictional forces of elastomeric whole tie and stainless steel whole tie (p>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.203-215
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• 2007

Statement of problem: Titanium and its alloy, with their excellent bio-compatibility and above average resistance to corrosion, have been widely used in the field of dentistry. However, the excessive oxidization of titanium which occurs during the process of firing on porcelain makes the bonding of titanium and porcelain more difficult than that of the conventional metal-porcelain bonding. To solve this problem related to titanium-porcelain bonding, several methods which modify the surfaces, coat the surfaces of titanium with various pure metals and ceramics, to enable the porcelain adhesive by limiting the diffusion of oxygen and forming the adhesive oxides surfaces, have been investigated. Purpose: The purpose of this study was to know whether the titanium-porcelain bonding strength could be enhanced by treating the titanium surface with gold and TiN followed by fabrication of clinically applicable porcelain-fused-to-titanium crown Material and method: The porcelain-fused-to-titanium crown was fabricated after sandblasting the surface of the casting titanium coping with $Al_2O_3$ and treating the surface with gold and TiN coating followed by condensation and firing of ultra-low fusing porcelain. To compare with porcelain-fused-to-titanium crowns, porcelain-fused-to-gold crowns were fabricated and used as control groups. The bonding strengths of porcelain-fused-to-gold crowns and porcelain-fused-totitanium crowns were set for comparison when the porcelain was fractured on purpose to get the experimental value of fracture strength. Then, the surface were examined by SEM and each fracturing pattern were compared with each other Result:Those results are as follows. 1. The highest value of fracture strength of porcelain-fused-to-titanium crowns was in the order of group with gold coating, group with TiN coating, group with $Al_2O_3$ sandblasting. No statistically significant difference was found among the three (P>.05). 2. The porcelain-fused-to-gold crowns showed the highest value in bonding strength. The bonding strength of crowns porcelain-fused-to-titanium crowns of rest groups showed bonding strength reaching only 85%-94% of that of PFG, though simple comparision seemed unacceptable due to the difference in materials used. 3. The fracturing patterns between metal and porcelain showed mixed type of failure behavior including cohesive failure and adhesive failure as a similar patterns by examination with the naked eye and SEM. But porcelain-fused-to-gold crowns showed high incidence of adhesive failure and porcelain-fused-to-titanium crowns showed high incidence of cohesive failure. Conclusion: Above results proved that when fabricating porcelain-fused-to-titanium crowns, treating casting titanium surface with gold or TiN was able to enhance the bonding strength between titanium and porcelain. Mean value of masticatory force was found to showed clinically acceptable values in porcelain bonding strength in all three groups. However, more experimental studies and evaluations should be done in order to get better porcelain bonding strength and various surface coating methods that can be applied on titanium surface with ease.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.2
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• pp.144-150
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• 2017

Purpose: The aim of this in vitro study is to investigate load bearing capacity of esthetic abutments according to the type of material and wall thickness. Materials and methods: 70 specimens equally divided into seven groups according to their abutment wall thicknesses. The abutments prepared with titanium 0.5 mm wall thickness were used as a control group (Ti-0.5), whereas zirconia abutments and resin nano ceramic abutments with wall thickness 0.5 mm, 0.8 mm and 1.0 mm were prepared as test groups (Zir-0.5, Zir-0.8, Zir-1.0 and RNC-0.5, RNC-0.8, RNC-1.0). All specimens were tested in a universal testing machine to evaluate their resistance to fracture and all of them underwent thermo-cycling before loading test. Mean fracture values of the groups were measured and statistical analyses were made using two-way ANOVA. Results: Zir-1.0 showed the highest mean strength ($2,476.3{\pm}342.0N$) and Zir-0.8 ($1,518{\pm}347.9N$), Ti-0.5 ($1,041.8{\pm}237.2N$), Zir-0.5 ($631.4{\pm}149.0N$) were followed. The strengths of RNC groups were significantly lower compared to other two materials (RNC-1.0 $427.5{\pm}72.1$, RNC-0.8 $297.9{\pm}41.2$) and the strengths of all the test groups decreased as the thickness decreases (P < .01). RNC-0.5 ($127.4{\pm}35.3N$) abutments were weaker than all other groups (P < .05). Conclusion: All tested zirconia abutments have the potential to withstand the physiologic occlusal forces in anterior and posterior regions. In resin nano ceramic abutments, wall thickness more than 0.8 mm showed the possibility of withstanding the occlusal forces in anterior region.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.408-419
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• 2007

In the child, it is very important that he/she will have the ability to suppress aesthetic restorative materials of secondary caries. With the representative preventive material against caries, the importance of fluoride is more emphasized. This study examined the differences in fluoride release and re-uptake among some restorative materials, following a treatment of APF gel and fluoride varnish. The surface roughness was observed under scanning electron microscope. Studying this will provide for the research to find effective restorative materials and fluoride type in tooth caries prevention. It is applied from presence at a clinic that restorative materials are resin, flowable resin, compomer and glass ionomer. Fluoride release was measured at 24-hour intervals for 7 days, 3-day intervals from 8th to 38th day using an ion-selective electrode and analyzer. Then, the materials were treated with the fluoride gel and fluoride varnish respectively, fluoride release was measured and specimens were evaluated under scanning electron microscope for 4 weeks. It was concluded that 1. Fluoride was released for 38 days from restorative materials under 1 ppm in case of flowable resin, 1-2 ppm in compomer and 2-8 ppm in glass ionomer, a few of fluoride was released after 45 days 2. Fluoride has more releasing after application of APF gel than fluoride varnish. Fluoride re-uptake was observed under 0.6-0.2 ppm in fluoride varnish and 0.6-2.6 ppm in APF gel after starting the procedure one day(p<0.05). For the remaining 4 weeks, they demonstrated a similar release. 3. Specimens were evaluated under scanning electron microscope. Applied fluoride in the experimental group surface was rougher than the control group that did not receive fluoride application. Fluoride varnish group had a smoother surface than both the APF gel group and the varnish APF gel group that received a fluoride application.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.28-37
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• 2017

Mineral trioxide aggregate have been used for many years as a pulp therapy material. The most widely used product, Proroot white $MTA^{(R)}$ has a major drawback that it causes tooth discoloration. This study assessed discoloration of crown when various MTA-based materials were placed in the coronal aspect of the root canal. Seventy-five single-rooted, unrestored premolar teeth were selected. The teeth were randomly assigned to four experimental groups, each of $Biodentine^{(R)}$, Proroot $wMTA^{(R)}$, $Endocem^{(R)}$, $RetroMTA^{(R)}$ and one negative control groups. Color measurements were utilized by the Commission International de I'Eclairage's L*a*b* system with spectrophotometer. The color was assessed eight times : initial, 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 16 weeks after the placement. Statistical analysis was performed using the 2-way repeated analysis of variance and Bonferroni's method with p < 0.05. Proroot $wMTA^{(R)}$ induced significant decreases in $L^*$ values during experiment period. Tooth samples from the $Endocem^{(R)}$ group presented indistinct grayish color changes. The $Biodentine^{(R)}$ and $RetroMTA^{(R)}$ showed color stability. Consequently, while Proroot $wMTA^{(R)}$ and $Endocem^{(R)}$ that contain bismuth oxide as a radiopacifier showed tooth discoloration, displayed no sign of discoloration $Biodentine^{(R)}$ and $RetroMTA^{(R)}$ that contain zirconium oxide as a radiopacifier.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1949-1957
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• 2013

The contents of ${\beta}$-carotene and retinol in processed and restaurant foods, such as Korean noodles, mandus, rice cakes and bread products, were quantified by high-performance liquid chromatography (HPLC) with UV/visible and fluorescence detector, respectively. Samples were collected from different local areas (i.e. Gangwon-do, Gyeonggi-do, Gyeongsang-do, Seoul, Jeolla-do, and Chungcheong-do). After homogenization, samples were hydrolyzed by direct alkali saponification; thereafter, fat-soluble components were extracted by a mixture of n-hexane/ethylacetate (85:15, v/v), containing 0.01% butylated hydroxytoluene (BHT). ${\beta}$-carotene and retinol contents in infant formula used as an in-house material for the analytical quality control. Among 14 Korean noodles, high contents of ${\beta}$-carotene were found in Bibim-Guksu (average 442.43 ${\mu}g/100g$) and Jjolmyeon (average 301.39 ${\mu}g/100g$). In 4 Korean mandus, the highest contents of ${\beta}$-carotene was determined in Kimchi-mandu (average 197.64 ${\mu}g/100g$), resulting in 33.3 RE of the converted vitamin A. Among 12 Korean rice cakes, Maeun-Tteokbokki and Modm-Chaltteok contained relatively high content of ${\beta}$-carotene with 205.11 and 41.33 ${\mu}g/100g$, respectively, while retinol was detected only in Maeun- Tteokbokki (1.65~10.45 ${\mu}g/100g$). In addition, among 8 bread products, 77.3 RE of pastry, 51.2 RE of buttercream- bread, and 41.4 RE of morning roll were found as the contents of the converted vitamin A.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1792-1798
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• 2016

This study investigated quality characteristics, antioxidant activities, and retarding retrogradation of Sulgidduck, traditional rice cake of Korea, prepared using rice flour added with 0%, 1%, 2%, 3%, and 4% pumpkin leaf powder. Moisture content of pumpkin leaf Sulgidduck showed a tendency to increase in the 1% and 2% added group but decrease in the 3% and 4% added group. pH level significantly increased (4.50~6.16) with an increase in content of pumpkin leaf powder (P<0.05). For color, as content of pumpkin leaf powder increased, L-value decreased and b-value increased. Hardness tended to increase with addition of pumpkin leaf powder except for the 1% added group. Springiness was not significantly different (P<0.05). Chewiness and adhesiveness increased according to addition level increase. Retarding retrogradation showed that the pumpkin leaf powder added group had a stronger effect compared to the control, whereas the 2% added group presented the most retarding retrogradation effect with the lowest Avrami exponent. Total phenols content and ABTS radical scavenging activity tended to increase as content of pumpkin leaf powder increased. Sensory properties by 7-point scale test showed that the 2% added group had the highest scores, whereas the 4% added group had the lowest scores. These results suggest that pumpkin leaf is considered as a good material to improve quality characteristics, antioxidant activities, and retarding retrogradation of Sulgidduck. The most appropriate proportion for the greatest effect of retarding retrogradation in Sulgidduck was considered to be 2%.