• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2003년도 추계국제학술대회
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• pp.160-161
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• 2003

In Korea, 1, 357 tonnes of benzoyl peroxide was produced as a white granule with purities ranging 22 to 95％ in 2001. 75% of benzoyl peroxide is mainly used in the manufacture of expandable styrene polymer and other resins as initiators of polymerization and also been used in the treatment of acne vulgaris and the medical product contains mainly 5 to 10% of it. A very small portion of benzoyl Peroxide is used as flour bleaching agent, Potential human exposure from workplaces is expected to be negligible because this chemical is produced in closed system in only one company in Korea and when a production facility monitors its workplace for the worker exposure annually, the concentration of airborne aerosols at the personal sampling has been less than 1mg/㎥.

• 전기화학회지
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• 제10권4호
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• pp.235-238
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• 2007

과산화수소의 발생은 일반적으로 유기 산화제를 포함한 산업적 프로세스의 넓은 분야에 응용된다. 과산화수소는 펄프와 제지 공업의 기계적, 화학적 처리를 위하여 사용되고 염소를 기초로 둔 화학제품에 알칼리 처리로 사용된다. 본 연구에서는 Nafiom과 러시아 양이온 교환막인 MK-40, 제조된 SPEEK막을 가스확산전극이 포함된 과산화수소 발생용 전해 셀에서 비교 실험한다. 다른 양성자 교환막에 효과에 따른 과산화수소 발생의 전기화학적 셀의 전압과 전류 효율, 에너지 소모를 연구한다.

• Restorative Dentistry and Endodontics
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• 제36권4호
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• pp.271-279
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• 2011

임상에서 복합 레진을 이용하여 자연치를 재현하는 과정은 매우 어려우며 이를 위해서는 색과 사용하는 재료에 대한 충분한 이해가 필요하다. 복합 레진은 자연치와 화학적 조성과 미세구조가 다르기 때문에 광학적 특성도 다를 수 밖에 없다. 본 논문에서는 색에 대한 기본적인 지식과 색을 측정하는 장비에 대한 이해, 그리고 자연치의 색에 대한 분석을 살펴보고, shade tab의 정확도에 대한 평가, 복합 레진의 중합 전후의 색 변화, 수분과 물에 의한 영향, 미백제의 의한 영향 및 투명도, 유백광 성질(opalescence), 형광성(fluorescence)에 대해 알아보고자 하였다.

• 한국식품위생안전성학회지
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• 제35권3호
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• pp.261-270
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• 2020

식품첨가물 중 주용도로 보존료가 제시되어 있는 발색제 3품목, 보존료 17품목 및 표백제 6품목을 대상으로 가공식품 유형별 사용 현황을 조사하였다. 발색제 3품목 중 아질산나트륨이 257건으로 가장 많이 사용되었으며, 양념젓갈(71.21%), 즉석섭취식품(7.78%), 빵류(7.00%) 등에 사용하였다. 보존료로 사용되는 안식향산류 중 안식향산나트륨의 사용 건수는 1,215건으로 안식향산류(총 1,236건)의 대부분을 차지하였고, 음료베이스(39.51%), 혼합음료(22.47%), 인삼·홍삼음료(8.89%) 등 음료류에 81.16%를 사용하였다. 데히드로초산나트륨은 총 57건 중 빵류(49.12%)와 마가린(21.05%)에 주로 사용하였다. 자몽종자추출물은 3,291건 사용되어 보존료 중 가장 많이 사용된 것으로 나타났다. 자몽종자추출물은 소스(54.65%), 액상차(10.46%), 기타가공품(5.15%), 인삼·홍삼음료(3.83%) 등 가공식품 식품유형 44종류에 사용되었다. 파라옥시안식향산에틸의 사용 건수는 2,957건으로서 파라옥시안식향산류의 대부분을 차지하였고, 소스(92.15%), 혼합간장(2.77%), 절임식품(1.52%) 등의 식품유형에 96.44%를 사용하였다. 프로피온산류 3종은 거의 대부분 빵류에 사용되었다. 소브산칼륨은 789건 중 절임식품(40.43%), 어묵(34.09%), 조미건어포(7.22%), 소스(4.06%) 등 주로 절임식품과 수산물가공식품류(총 47.15%)에 사용한 것으로 나타났다. 소브산은 27건의 사용사례 모두 어묵(100%)에 사용된 것으로 나타났다. 표백제로 사용되는 아황산염류 6품목 중 산성아황산나트륨과 차아황산나트륨은 주로 과자류, 빵류 또는 떡류에, 메타중아황산칼륨, 메타중아황산나트륨 및 무수아황산은 주로 과실주 등 주류에, 아황산나트륨은 절임식품에 주로 사용하는 것으로 나타났다. 본 연구 결과는 보존료를 주용도로 하는 식품첨가물을 가공식품에 사용하는데 유용하게 이용될 수 있을 것으로 생각된다.

• 대한화학회지
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• 제4권1호
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• pp.70-77
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• 1957

4,5-Diphenyl Imidazolone is synthesized from Benzoin, Urea, and Acetic acid catalyser. Nowadays, it is being used as an optical bleaching agent for wool and nylon textiles. Up to now, only one process of synthesis has been known. In order to find out the best conditions governing the yield were examined under various catalysers and conditions. In this experiment, the summary of results were as follows. a. On Acetic acid catalyser. The maximum yield conditions were mol ratio (Benzoin: Urea: Acetic acid) 1 : 2 : 14, Acetic acid concentration 99.9%. Reaction temperature 115$^{\circ}$. Under reaction time of 2 hours, above yield was 96.4%. b. On Mineral acid Catalyser. In using of Sulfonic acid, the color of solution was changed dark purlish black. With other mineral acid catalysers, in spite of increasing of temperature, it was proved that Benzoin floats on the solution, so that this reaction could not be continue. c. On Phosphoric acid catalyser. It was made clear that it can not be used for this reaction. d. On Sodium hydroxide catalyser. As one of Alkali catalyser, Sodium hydroxide was examined but this was unsuitable substance for this reaction. e. On Formic acid catalysers. The maximum yield conditions were mol ratio (Benzoin: Urea: Formic acid) 1: 2: 30. Formic acid concentration 85.%. Reaction temperature 150∼110$^{\circ}$. Under reaction time of 90 minutes, the best yield was 87%. Hereby, it was proved that organic acids such as Acetic acid and Formic acid can be used. When using Acetic acid, the yield was better than Formic acid, but it takes longer reaction time than Formic acid. About the fluorescent effect, the temperature of dye-bath must not be over 904,5-Diphenyl Imidazolone is synthesized from Benzoin, Urea, and Acetic acid catalyser. Nowadays, it is being used as an optical bleaching agent for wool and nylon textiles. Up to now, only one process of synthesis has been known. In order to find out the best conditions governing the yield were examined under various catalysers and conditions. In this experiment, the summary of results were as follows. a. On Acetic acid catalyser. The maximum yield conditions were mol ratio (Benzoin: Urea: Acetic acid) 1 : 2 : 14, Acetic acid concentration 99.9%. Reaction temperature 115$^{\circ}$. Under reaction time of 2 hours, above yield was 96.4%. b. On Mineral acid Catalyser. In using of Sulfonic acid, the color of solution was changed dark purlish black. With other mineral acid catalysers, in spite of increasing of temperature, it was proved that Benzoin floats on the solution, so that this reaction could not be continue. c. On Phosphoric acid catalyser. It was made clear that it can not be used for this reaction. d. On Sodium hydroxide catalyser. As one of Alkali catalyser, Sodium hydroxide was examined but this was unsuitable substance for this reaction. e. On Formic acid catalysers. The maximum yield conditions were mol ratio (Benzoin: Urea: Formic acid) 1: 2: 30. Formic acid concentration 85.%. Reaction temperature 150∼110$^{\circ}$. Under reaction time of 90 minutes, the best yield was 87%. Hereby, it was proved that organic acids such as Acetic acid and Formic acid can be used. When using Acetic acid, the yield was better than Formic acid, but it takes longer reaction time than Formic acid. About the fluorescent effect, the temperature of dye-bath must not be over 90$^{\circ}$. and the ratio of 4,5-Diphenyl Imidazolone and water should be from 1:50000. to 1:10000. It proved that the best effect on textiles, and the best condition were dye-temperature near 704,5-Diphenyl Imidazolone is synthesized from Benzoin, Urea, and Acetic acid catalyser. Nowadays, it is being used as an optical bleaching agent for wool and nylon textiles. Up to now, only one process of synthesis has been known. In order to find out the best conditions governing the yield were examined under various catalysers and conditions. In this experiment, the summary of results were as follows. a. On Acetic acid catalyser. The maximum yield conditions were mol ratio (Benzoin: Urea: Acetic acid) 1 : 2 : 14, Acetic acid concentration 99.9%. Reaction temperature 115$^{\circ}C$. . Under reaction time of 2 hours, above yield was 96.4%. b. On Mineral acid Catalyser. In using of Sulfonic acid, the color of solution was changed dark purlish black. With other mineral acid catalysers, in spite of increasing of temperature, it was proved that Benzoin floats on the solution, so that this reaction could not be continue. c. On Phosphoric acid catalyser. It was made clear that it can not be used for this reaction. d. On Sodium hydroxide catalyser. As one of Alkali catalyser, Sodium hydroxide was examined but this was unsuitable substance for this reaction. e. On Formic acid catalysers. The maximum yield conditions were mol ratio (Benzoin: Urea: Formic acid) 1: 2: 30. Formic acid concentration 85%. Reaction temperature 150∼110$^{\circ}C$. Under reaction time of 90 minutes, the best yield was 87%. Hereby, it was proved that organic acids such as Acetic acid and Formic acid can be used. When using Acetic acid, the yield was better than Formic acid, but it takes longer reaction time than Formic acid. About the fluorescent effect, the temperature of dye-bath must not be over 90$^{\circ}C$. and the ratio of 4,5-Diphenyl Imidazolone and water should be from 1:50000. to 1:10000. It proved that the best effect on textiles, and the best condition were dye-temperature near 70$^{\circ}C$. and dye-time 15 minutes. . and dye-time 15 minutes. . and the ratio of 4,5-Diphenyl Imidazolone and water should be from 1:50000. to 1:10000. It proved that the best effect on textiles, and the best condition were dye-temperature near 70$^{\circ}C$. and dye-time 15 minutes.

• Restorative Dentistry and Endodontics
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• 제19권2호
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• pp.585-601
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• 1994

The purpose of this study was to evaluate the ability of several intracoronal base materials to prevent cervical leakage of a bleaching agent into the dentinal tubules and along the root canal. In this study, thirty-two anterior teeth were used. After lingual access was prepared in each tooth, tooth was instrumented with a step-back technique to a Nos. 40-50 using K-type files. All teeth were obturated with a lateral condensation technique. Excess gutta percha was removed with a warm instrument to the facial level of the CEJ. Teeth were divided into four groups : Teeth in control group were not filled with base material. Teeth in groups 1, 2, and 3 had 2mm of gutta percha removed with a warm instrument, then Dycal, Fuki II LC and Z-100 were filled with palstic instruments on the top of the gutta percha respectively. All teeth were bleached for 7 days, fresh bleach was added for another 7 days, then a 10 % methylene blue dye was placed inside the access preparation. They were stored at $37^{\circ}C$ and $100^{\circ}C$ humidity for 5 days. Each tooth was sectioned perpendicular to the long axis using a diamond disk. Initial cuts were made at the most coronal level of facial and lingual CEJ's, then another cuts continued appically in the levels of 0.5mm, 1.5mm, and 2.0mm respectively. The amount of dye leakage through the dentinal tubules was determined at each cut section. In addition, when the cut specimen was determined to be last penetration of any dye, this level was recorded as depth of apical leakage from the coronal terminus of the gutta percha, Dycal, Fuji II LC and Z-100. The acquired data were analyzed by Tukey's Multiple Range Test adn Cochran-Mantel-Haenszel Test to see if there was any statistically significant difference in dye penetration and linear apical leakage among the groups. The results were as follows : 1. Control group at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 AND 3 at level of 2.0mm showed the least dye penetration through the facial or lingual dentinal tubules, but there were no significant difference among three groups. 2. Group 2 at levels of CEJ and 0.5mm, group 3 at level of 1.5mm, and group 2 and 3 at level of 2.0mm showed the least dye penetration through the proximal dentinal tubules, but there were no significant difference among control group, group 2, and group 3. 3. Group 1 showed the greatest dye penetration through the facial or lingual and proximal dentinal tubules at all levels, and there were significant difference with other three groups. 4. Control group and group 1 showed 2mm apical dye leakage at facial or lingual and proximal aspects, group 2 showed 1.5mm, and group 3 showed 0.5mm.

• Restorative Dentistry and Endodontics
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• 제34권2호
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• pp.154-161
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• 2009

8.3%의 carbamide peroxide를 함유한 펜형 코팅용 미백제인 BlancTis Forte (NIBEC, Seoul & JinCheon)를 실험군으로, 3% hydrogen peroxide를 함유한 Whitening Effect Pen (LG, Seoul) 제재를 대조군으로 각각 피험자 20명에게 2시간씩 1일 2회 제조사의 지시대로 치아표면에 4주간 적용하도록 지시하고 색조개선 효능과 안전성을 평가하였다. 미백 효과는 미백 전 및 미백 2주, 4주, 및 미백 종료 4주 후에 $Shadepilot^{TM}$을 이용하여 색 변화를 측정하였고. 매 내원시기마다 모든 환자는 치수생활력 검사와 치주 및 치태 검사를 통해 부작용 여부 (치아과민증 및 구강 내 연조직의 부작용)를 기록한 후 다음과 같은 결과를 얻었다. 1, 실험군 및 대조군의 색 변화량 (${\Delta}E$)은 2이상으로 인지할 수 있는 색 변화를 보였으며, 두 제품간에는 통계적으로 유의한 차이를 보이지 않아 (p > 0.05) 유사한 미백효능을 나타냄을 알 수 있었다. 2. 미백효과는 명도의 개선보다는 주로 a, b값의 변화에 의한 것으로 특히 실험군에서 b값의 변화, 즉 황색조의 개선효과가 대조군에 비해 유의성 있게 높은 것으로 나타났다 (p < 0.05). 3. 치아나 치은의 과민증이나 이상증상을 호소하는 피험자는 없어 두 제품 모두 안전성을 확인할 수 있었다.

• Natural Product Sciences
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• 제19권1호
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• pp.54-60
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• 2013

Rhus verniciflua Stokes (Anacadiaceae) is a plant that is native to East Asian countries, such as Korea, China, and Japan, and it has been found to exert various biological activities including antioxidative, anti-aggregatory, anti-inflammatory, anti-mutagenic, and apoptotic effects. Sulfuretin is one of the major flavonoid component isolated from the heartwood of R. verniciflua. Reactive oxygen species (ROS), produced via dental adhesive bleaching agents and pulpal disease, can cause oxidative stress. In the present study, we isolated sulfuretin from R. verniciflua and demonstrated that sulfuretin possesses cytoprotective effects against hydrogen peroxide ($H_2O_2$)-induced dental cell death. $H_2O_2$ is a representative ROS and causes cell death through necrosis in human dental pulp (HDP) cells. $H_2O_2$-induced cytotoxicity and production of ROS were blocked in the presence of sulfuretin, and these effects were dose dependent. Sulfuretin also increased heme oxygenase-1 (HO-1) protein expression. In addition, to determine whether sulfuretin-induced HO-1 expression mediated this cytoprotective effect, HDP cells were cotreated with sulfuretin in the absence or presence of SnPP, an inhibitor of HO activity. Sulfuretin-dependent HO-1 expression was required for suppression of $H_2O_2$-induced HDP cell death and ROS generation. These results indicate that sulfuretin-dependent HO-1 expression was required for the inhibition of $H_2O_2$-induced cell death and ROS generation. In addition, sulfuretin may be used to prevent functional dental cell death and thus may be useful as a pulpal disease agent.

• 한국환경과학회지
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• 제13권12호
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• pp.1109-1115
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• 2004

This study was investigated the residual contents of sulfur dioxide on the 373 kinds of herbal medicine distributed from Korea, China, and Japan. A modified Monier-Williams method was described for the determination of $SO_{2}$ contents in herbal medicines. The residual contents of $SO_{2}$ were not detected at 221 products$(59.8{\%})$ in total 373 products. Regardless of region, $SO_{2}$ contents were not found at Farfarae Flos, Zizyphi Spinosi Semen, Castanea crenata, and Strychni Ignatii Semen. But it's found at Asparagi Radix, Codonopsitis Radix, Lilii Bulbus, and Kaempferiae Rhizoma of every region collected the samples. Also, $SO_{2}$ contents were not detected at the herbal medicines which collected cultural fields of dometic. $SO_{2}$ contents ranged 11$\~$3990 mg/kg(mean 152 mg/kg) at domestic samples, 11$\~$3440 mg/kg(mean 603 mg/kg) at imported samples. After treated with water wash and hot water extraction, the reduction rates of sulfur dioxide were appeared with $24.4{\%}\~68.7{\%}\;and\;83.8{\%}\~100.0{\%},$ respectively. These data will be used to establish a criteron of residual sulfur dioxide in herbal medicines.

• 펄프종이기술
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• 제45권6호
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• pp.17-23
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• 2013

The reduction of metal ion from the cotton linter for the preparation of NMMO (N-methylmorpholine N-oxide)-based dissolving pulp was investigated. The NMMO-based dissolving pulp was usually used for the manufacture of high quality fabrics, and need to have high alpha cellulose content and high brightness. NMMO, which is environmentally friendly, and reusable after recovering process, is very sensitive to the metal ions such as Cu, Fe, Mg, and Cr. Electron beam, sulfuric acid, acetic acid, and ozone treatment before bleaching were used and the concentration changes of the metal ions were compared to that of EDTA, a chelating agent. It was found that both acid treatments (sulfuric and acetic acid) were very effective and comparable to EDTA treatment at the same dosage in metal ion reduction, but electron beam and ozone treatment were not. The sulfuric acid treatment turned out to be effective in metal ion reduction, and most inexpensive.