• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.477-482
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• 2014

We immobilized Thermomyces lanuginosus lipase to catalyze transesterification reaction in DMF. This lipase was selected after screening among other commercial lipases. We found that prepared immobilized lipase is particularly useful for preparation of 6-O-acylsucrose with higher conversion rate even in 10 g scale. Several solvents were evaluated for selective transesterification reaction. We noticed that the immobilized lipase retained more than 80 % activity after 5 cycles of 96 h reaction. A general method was also developed to purify the products using simple crystallization and precipitation process. Furthermore, 6-O-vinyladipoylsucrose was subjected to synthesis of the corresponding polymer by radical initiator. The sucrose branched polymer can be used further for evaluation of its biodegradability and other biological applications.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.19-22
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• 1989

The suitability of BMPI (2-bromo-N-methyl pyridinium iodide) for solid-phase peptide synthesis was investigated. The coupling rate of BMPI/HOBT procedure. BMPI/HOBT was superior to DCC/HOBT couplings using the solid-phase peptide bond formation proceeded to a greater degree of completion than DCC/HOBT method did. Double couplings with 2 equiv. of Bocamino acids and 1.5 equiv. of BMPI and $NEt_3$ and 2 equiv. of HOBT in DMF/MC (1:1 v/v) gave the best result for the preparation of a model compound. Stepwise solid phase peptide synthesis using BMPI/HOBT procedure was successfully utilized for the preparation of $(D-Ala)^2$-dynorphine A. BMPI/HOBT procedure for the synthesis of $(D-Ala)^2$-dynorphine gave better yield (20%) than DCC/HOBT procedure did.

• Journal of the Korean Ceramic Society
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• v.55 no.1
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• pp.90-93
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• 2018

In this study, n-type $Bi_2Te_3$ in thermoelectric scrap is recovered through a wet reduction process. The recovered powder (tellurium) is grafted onto gas sensor in a new application that is not a thermoelectric device. Bismuth-rich powder is prepared by adding hydrazine when pH of the solution is brought to 13 using NaOH. The pH of the filtered solution was reduced using $HNO_3$, and then hydrazine was added to perform the re-reduction reaction. The tellurium-rich powder can be obtained through this reaction. The elemental analysis for these powders is confirmed by energy dispersive X-ray spectroscopy (EDS) analysis ; the successful separation of bismuth and tellurium is confirmed. Separated tellurium powder is mixed with DMF solvent and ethyl cellulose binder to confirm gas sensing properties. The tellurium paste was exposed in $NO_x$ atmosphere and exhibited a rapid reaction rate and recovery rate of less than 3 minutes for the gas.

• Journal of agricultural medicine and community health
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• v.21 no.2
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• pp.221-230
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• 1996

This study was purposed to develop the fluoride mouthrinsing project through the public health system in a rural area. This project was performed under the management of the public health dentist for the 3rd grade students selected from the 5 primary schools at Goksunggun in Chonnam area. Fluoride mouthrinsing was executed with 0.2% neutral sodium fluoride solution once a week. After 1 year's fluoride mouthrinsing project, DMFT index, DMF rate frequencies of toothbrushing, simplified oral hygiene index, and the responses to fluoride mouthrinsing project of the school children participated were examined. The results obtained from this study were as follows: 1. The fluoride mouthrinsing project for school children was performed average 10 times a year by the public health dentist. They were relatively little active to perform this project. 2. There was no significant difference in the increasement of DMFT index and DMF rate during 1 year between control and fluoride mouthrinsing group. 3. Control group was increased higher than fluoride mouthrinsing group in simplified oral hygiene index. 4. Toothbrushing frequencies increased in both groups. 5. 80.4% of school children participated in fluoride mouthrinsing project was responded to like it, and 78.2% among them was responded the project to be beneficial for their dental health. 6. 39.2% of school children was responded to have water-like taste for fluoride solution. But 34.0% of them was done to have strange taste. On consideration of above findings, this fluoride mouthrinsing project was not well performed by the public health dentists and also the oral health status of school children participated was not significantly improved by this project. Therefore, to perform continually this project well, it was recommended that this project should be performed by other person such as dental hygienist rather than public health dentist.

• Journal of dental hygiene science
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• v.11 no.5
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• pp.423-430
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• 2011

This study aims to provide basic information for conducting reducing children's dental caries, and proper eating habits and ineffective oral health education activities by survey of children's oral examination and their mothers based on 9 elementary school at a local area in Gyeonggi Province from May, 4 until July, 20 2009, and the results were as follows: 1. The children's DMF rate by gender was higher in men than women, the children's dental caries by grades was higher in higher grades than lower grades, so there were statistically significant differences between children's dental caries experiences in gender and grades(p<0.05). 2. Mother's socio-economic characteristics, mother's detergent food intake frequency, the mother's protective food intake frequency and the snack consumption etc. had not great effects on the children's dental caries(p>0.05). In the dental caries experience in children according to the maternal eating behavior, there were the significant differences(p<0.05) between the degree of unbalanced diet in mother and dental caries experience df index in children. Proper eating behavior of balanced diet in mother must take precedence for children's oral health, and required for their children to have interests about proper eating habits and oral health.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.348-351
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• 2003

산소 과전압이 낮은 $MnO_2$를 촉매로 사용하여 반도체 산화물계의 산소선택성 전극을 제조하고 산화물 coating층의 미세구조와 전기화학적 특성을 분석하였다. Ti 기판에 열분해 법을 이용하여 $MnO_2$ 피막을 형성하였고, 또한 PVDF : $MnO_2$의 함량비를 1 : 1에서 1 : 40까지 정량적으로 변화시키고 DMF의 함량을 각각의 고정된 PVDF : $MnO_2$의 함량비에서 변화시켜 Pb전극에 1.5 mm/sec의 속도로 5회 dipping하여 $MnO_2$ 피막층을 형성 하였다. $450^{\circ}C$에서 1시간 열분해하여 약 $1\;{\mu}m$의 $MnO_2$ 피막층이 형성되었으나 Ti 기판과의 접착력이 약하여 피막자체에 대한 전기화학적 특성을 관찰할 수 없었다. PVDF : DMF = 4 : 96인 경우 pb 전극의 피막층이 얇기 때문에 박리현상이 일어났으며 이는 산화물 용제의 낮은 점도 때문인 것으로 판단된다. 또한 PVDF : DMF = 10 : 90의 경우는 5회 dipping 하여 약 $150\;{\mu}m$의 피막층을 형성하였다. PVDF : $MnO_2$의 함량비가 1:1에서 1:6 까지는 DMF의 함량에 무관하게 전극 특성이 나타나지 않았지만 $MnO_2$의 양이 상대적으로 증가하면 cycle이 증가하더라도 거의 일정한 전류 값을 갖고 $MnO_2$와 PVDF의 비가 20:1 이상의 조성에서는 균일한 CV 특성을 나타냈다. 이는 $MnO_2$가 효과적으로 촉매 작용을 한 것으로 판단되며 anodic polarization에 의한 산소 발생 과전압도 약 1.4V 정도로 감소되었다.동등한 MSIL 코드를 생성하도록 시스템을 컴파일러 기법을 이용하여 모듈별로 구성하였다.적용하였다.n rate compared with conventional face recognition algorithms. 아니라 실내에서도 발생하고 있었다. 정량한 8개 화합물 각각과 총 휘발성 유기화합물의 스피어만 상관계수는 벤젠을 제외하고는 모두 유의하였다. 이중 톨루엔과 크실렌은 총 휘발성 유기화합물과 좋은 상관성 (톨루엔 0.76, 크실렌, 0.87)을 나타내었다. 이 연구는 톨루엔과 크실렌이 총 휘발성 유기화합물의 좋은 지표를 사용될 있고, 톨루엔, 에틸벤젠, 크실렌 등 많은 휘발성 유기화합물의 발생원은 실외뿐 아니라 실내에도 있음을 나타내고 있다.>10)의 $[^{18}F]F_2$를 얻었다. 결론: $^{18}O(p,n)^{18}F$ 핵반응을 이용하여 친전자성 방사성동위원소 $[^{18}F]F_2$를 생산하였다. 표적 챔버는 알루미늄으로 제작하였으며 본 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화가 선조체 영역에서 국한되어 나타나며 그 유의성이 움직임 보정 전에 비하여 낮음을 알 수 있었다. 결론: 뇌활성화 과제 수행시에 동반되는 피험자의 머리 움직임에 의하여 도파민 유리가 과대평가되었으며 이는 이 연구에서 제안한 영상정합을 이용한 움직임 보정기법에 의해서 개선되었다. 답이 없는 문제, 문제 만들기, 일반화가 가능한 문제 등으로 보고, 수학적 창의성 중 특히 확산적 사고에 초점을 맞추어 개방형 문제가 확산적 사고의 요소인 유창성, 독창성, 유연성 등에 각각 어떤 영향을 미치는지 20주의 프로그램을 개발, 진행하여 그 효과를 검증하고자

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.262-273
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• 2000

The purpose of this study was to investigate the difference between the children who experienced nursing caries and the children who were caries-free in the prevalence of enamel hypoplasia and DMF rate and to analyse causal factors from questionnaires. Oral examination was performed on 101 children(nursing caries group-45, caries-free group-56)in the 1994 at first, later in 1999. Parents were asked to write questionnaires. As a cotrol group, 50 children were chosen randomly. The results obtained from this study were as follow: 1. The prevalence of enamel hypoplasia of the children who experienced nursing caries was higher significantly than that of the all of the examined children (P<0.01). 2. DMF Tate of the children who experienced nursing caries was higher significantly than that of the children who were caries-free (P<0.01), and higher than that of the all of the examined children also(P<0.05). 3. The children who experienced nursing caries performed tooth brushing less frequently (P<0.05) and started tooth brushing later than the children who were caries-free (P<0.01). 4. The children who experienced nursing caries ate cariogenic food more frequently(P<0.05) and had higher preference(P<0.05) than the children who were caries free. 5. The children who experienced nursing caries showed lower frequency of periodic dental examination than the children who were caries-free or centre) group(P<0.05).

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.476-481
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• 2004

The aim of this study was to formulate a sustained release system for indomethacin (IND) with rosin gum obtained from a pine tree. Rosin microparticles were prepared by a disper­sion and dialysis method without the addition of surfactant. In order to investigate the influence of solvents on the formation of colloidal microparitcles, various solvents like ethanol, DMF, DMAc, and acetone were used. The rosin microparticles containing IND were characterized by X­ray differactometry (XRD) and differential scanning calorimetry (DSC). The morphologies of rosin microparticles observed by scanning electron microscopy (SEM) were spherical. The solvents used to dissolve rosin significantly affected the drug content and drug release rate of IND. The release behaviors of IND from the rosin microparticles were dependent on the drug content and size of the particles. Rosin micorparticles with a higher drug content and of a larger particle size had a slower drug release rate. Also, the IND release rate from the rosin microparticles could be regulated by the rosin content in the microparticles. From these results, rosin microparticles have the potential of being used as a sustained release system of IND.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1579-1584
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• 2002

Since surfactant or emulsifiers remained on the nanoparticle surface significantly affect the physicochemical properties, the biodegradation rate, the biodistribution, and the biocompatibility of nanoparticles, surfactant-free nanoparticles should be good candidate. surfactant-free PLGA nanoparticles were successfully prepared by both the dialysis method and the solvent diffusion method. The PLGA nanoparticles prepared using the solvent diffusion method has a smaller particle size than the dialysis method. The solvent diffusion method was better for a higher loading efficiency than the dialysis method but the nanoparticle yield was lower. Testosterone (TST) release from the PLGA nanoparticles was dependent on the particle size rather than the drug contents. Testosterone release from the PLGA nanoparticles prepared by the solvent diffusion method using acetone was faster than those prepared by the dialysis method. TST release from the PLGA nanoparticles prepared by the solvent diffusion method using acetone and the dialysis method using dimethylformamide (DMF) was completed for 4 days while the PLGA nanoparticles prepared by the dialysis method using acetone showed approximately 80% TST release after 4 days. Since the PLGA nanoparticle degradation ratio was below 20% within 5 days at all samples while TST release completed within 4 days, TST release was dependent on the diffusion mechanism rather than degradation.

• The Korean Journal of Food And Nutrition
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• v.13 no.4
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• pp.360-364
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• 2000

We studied the degree of rancidity of linoleic acid for the electrochemical redox reaction in time course and the kinetic parameters. The current of the linoleic acid was increased and the potential was shifted to the positive potential when scan rates were faster. The redox reaction of the linoleic acid was proceeding to totally irreversible and diffusion controlled reaction. From these results, diffusion coefficient(D$\_$o/) of linoleic acid was observed to 2.61$\times$10$\^$-6/ ㎠/s in the 0.1 M TEAP/DMF electrolyte solution. Also, exchange rate constant(K$\^$o/) was observed to 9.79$\times$10$\^$-11/ cm/s. The leaving time in air condition was found to affect the rancidity. We predicted that the product was carbonyl compounds.