• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.95-99
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• 1995

We have previously established a system for plant regeneration through somatic embryogenesis and Agrobacterium-mediated transformation of Korean ginseng. In this study to produce a fungus-resistant plant, we introduced a bean chitinase gene into ginseng using the transformation system. A binary vector pChi/748 was constructed by introducing the bean basic chitinase gene into EcoRI site of pGA748 which carries the CaMV 35S promoter governing the introduced gene and neomycin phosphotransferase II(NPT-II)gene as a positive selection marker. Cotyledonary explants were cocultured with A. tumefaciens strain LBA4404 harboring the binary vertor pChi/748 for 48 h, and transferred to MS medium supplemented with l mg/L2,4-D,0.1mg/L kinetin, 100 mg/L kanamycin, and 500mg/L carbenicillin. Kanamycin-resistant calli were formed on the cut surface of cotyledonary explants after one month of culture, and subsequently they gave rise to somatic embryos. Upon transfer onto medium containing 1 mg/L each of BA and GA$_3$, most of them converted to plantlets after 5 weeks of culture. The genomic DNA of eight kanamycin-resistant regenerants was subjected to polymerase chain reaction (PCR) using two specific 21-mer oligonucleotides derived from the chitinase gene. PCR-Southern blot analysis confirmed that the chitinase gene was incorporated into six out of the eight regenerants..

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.422-428
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• 2006

Dentin bonding system have recently been developed in an effort to simplify and shorten bonding procedure. The intent of this study was to evaluate microleakage of newer generation of dentin bonding system comparing with other generations. Forty extracted human premolar teeth were randomly assigned to four groups for bonding : the 4th generation bonding system (Scotchbond Multi-Purpose). the 5th generation bonding system (Clearfil SE Bond), 6th generation bonding system (AQ bond) and 7th generation bonding $system(i-bond)^{TM}$ Class V cavities were prepared in buccal and lingual surface. The cavities were restored with composite resin (Z100) after the application of dentin bonding systems according to the instructions of the manufacturer Samples were thermocycled and immersed in methylene blue dye(2%). Each sample was sectioned with Isomet and evaluated for microleakage using stereomicroscopy. The mean value of the microleakage in 7th generation bonding system was greater than those of 4, 5, 6th generation dentin bonding system. Statistically, the mean values of microleakage between 4th and 7th generation bonding system were significantly different from each other (p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.247-252
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• 2013

Pit and fissure sealant prevents biofilm accumulation, plays a role in forming a barrier to acidic substance made by the bacteria. The Surface reaction-type pre-reacted glass ionomerI(S-PRG) filler was developed in 1999. S-PRG filler releases fluoride continuously and does not decompose under wet conditions. The aim of this study was to test the microleakage and anticariogenic effect to adjacent enamel of S-PRG filler-containing pit and fissure sealant. Sound premolars and molars were used in this study. A S-PRG filler-containing pit and fissure sealant, Beautisealant$^{(R)}$(Shofu, Japan) was used for this experiment, the composite resin sealant Concise$^{(R)}$(3M ESPE, USA) was used as control. For the microleakage test, all teeth surface were double coated with finger nail varnish, with the exception of a 1.0 mm window around the restoration margins. The teeth were immersed in 2% methylene blue solution for 24 hours and then rinsed in tap water. For the anticariogenic effect evaluation, all tooth were immersed in artificial carious solution for 9 days and rinsed with tap water. Each tooth was embedded in orthodontic acrylic rein and subsequently sectioned longitudinally in a bucco-lingual direction with a low-speed diamond saw. The cut sections were examined using a stereomicroscope. Differences in microleakage between the two groups were not different significantly. But the S-PRG filler-containing pit and fissure sealant showed higher anticariogenic effect than that of flowable resin sealant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.383-389
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• 2012

The objective of this study was to develop and standardize a preparation method for low-salt yacon jangachi using rice wine lees. The proximate composition of yacon was 81.08% (moisture), 0.77% (crude protein), 0.14% (crude lipid) and 0.70% (crude ash). In order to determine the preferred sodium concentrations of soaking solution and rice wine lees, we investigated the quality characteristics of yacon jangachi during storage for 50 days at $18^{\circ}C$. The salinity of yacon jangachi using rice wine lees with 2% and 4% salt increased with storage time, but the salinity did not rise above 3% during storage for 50 days. The salinity of rice wine lees with 4% salt decreased during storage time. a and b color values along with sheared force of yacon jangachi increased as storage time increased, but L color value was reversed. In the sensory evaluation, the color preference for yacon jangachi increased during storage time, and the taste preference was highest at day 30. The flavor preference decreased during storage time, but the texture preference was reversed. In the sensory evaluation of overall preference, yacon jangachi using rice wine lees with 0% salt decreased at day 30, whereas yacon jangachi using rice wine lees with 2% and 4% salt increased during storage time. In conclusion, the salinity of yacon jangachi stored for 50 days with 4% salt did not rise above 3%, and softening was not observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.965-970
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• 2002

This study was conducted to investigate inhibition effect of sanitizers against E. coli and a hygienic condition on the surface of utensils and equipments which were used to food service. Samples swabbed using cotton were collected from the surface of stainless steel, wood and plastic utensils and equipments which were used to food service at four elementary schools in Busan and analyzed by measuring the total, coliform and Salmonella spp. count. Total plate counts were 10$^4$~10$^{5}$ CFU/100 cm$^2$ in most of utensils and equipments except plastic cutting board. There were lots of coliforms in slicer (2.8$\times$10$^1$CFU/100 cm$^2$) and peeler (1.1$\times$10$^1$CFU/100 cm$^2$). It was indicated that the sanitary condition of some utensils and equipments such as slicer and peeler should be improved promptly. To investigate inhibition effect of sanitizers against E. coli, the surface of utensils and equipments used in food service was treated at different concentration of sodium hypochlorite for 1 minute and 3 minutes, respectively. The plastic utensils and equipments were most effective aganist E. coli at 100 ppm sodium hypochlorite for 3 minutes. But the stainless steel and wood were most effective at 200 ppm sodium hypochlorite for 3 minutes. It was also treated with 70% ethyl alcohol for 10 seconds and 30 seconds, respectively. The stainless steel utensils and equipments were most effective aganist E. coli at 10 seconds, but plastic and wood were most effective at 30 seconds. Therefore, the results of this study indicated that standardization of disinfection method of utensils and equipments used in food service should be given and sanitation training for dietition should be conducted continuously.

• Polymer(Korea)
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• v.25 no.1
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• pp.142-150
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• 2001

Until now rubber industry field has used organic solvent base adhesive, there was always existed a fire risk, variety of quality and harmfulness of human body. To solve this problem we were developed a new adhesive that was maked by raw materials of hydrocarbon series which has the properties of nonvolatile and high flash point. Because of this new adhesive has the properties of nonvolatile and non-harmfulness to the human body, we expected to solve the problems of a fire hazard and the pollution of the environmental. Instead of the rubber binder that is used to a present adhesive, the new idea is adopted in a new type of adhesive. Nonvolatile solvent penetrated to the rubber surface and caused the swelling in rubber surface and as a result of this action, it has the self-adhesive power. In comparision with the present adhesive a new type of adhesive remarkably improved the maintenance time of adhesion and the durability of this adhesive showed similar aspect. Because it did not exhibit a drop of physical properties of rubber which was caused by swelling effect, we estimate that new type adhesive are very stable and not reacted to several rubber additives. While present adhesive appear the crack at cutting surface of curing rubber that caused by gas, new type adhesive not exist these crack.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.543-549
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• 2000

Gutta-percha와 근관sealer를 사용한 근관 충전은 가장 많이 이용되고 성공률이 높은 방법이지만, 현재 사용되는 모든 근관sealer는 미세누출을 나타낸다. 따라서 더 효과적인 근관 폐쇄를 이루기 위한 재료 및 방법들이 연구되어왔다. 이중 상아질 접착제는 근관 충전재와 함께 사용되어 미세누출을 감소시키지만, 근관 내에 사용하기에 술식이 복잡하고 기술이 요구된다. 본 연구의 목적은 gutta-percha와 레진계 근관 sealer로 충전한 근관에서 self-etching primer를 미리 도포한 경우와 도포하지 않은 경우의 치근단 미세누출을 비교하고, self-etching primer를 도포함에 있어 근관 내에 적용하는 방법에 따른 미세누출을 비교하는 것이다. 또한 근관sealer와 상아질 계면을 주사전자현미경으로 관찰하여, 이 결과를 미세누출과 관련시켜보고자 하였다. 36개의 발거된 사람의 단근치에서 치관부를 절단, 제거하고 ProFile로 근관 형성한 후, 무작위로 선택하여 4개의 군으로 분류하였다. 1군에서는 주사기와 30게이지 주사 바늘로 self-etching primer를 근관 내에 적용하였고, 2군에서는 self-etching primer를 paper point에 적셔 근관 내에 적용하였다. 3군에서는 self-etching primer를 적용하지 않았다. 1, 2, 3군의 치아를 gutta-percha와 AH26 sealer를 사용하여 continuous wave 충전법으로 충전한 후 치근단공 주위 3mm를 제외한 치근변에 nail polish를 2회 도포하였고, 4군(음성 대조군)은 치근면 전체에 도포하였다. 1군과 2군에서 각각 2개의 치아는 주사전자현미경적 관찰을 위해 준비하였다. 모든 치아를 Methylene Blue 수용액에 48시간동안 침적, 수세한 후 치아 장축에 평행하게 양분하여 10배의 실물확대현미경 하에서 치근단 색소 침투를 관찰하였다. Self-etching primer를 도포한 군과 도포하지 않은 군 사이에는 평균 미세누출량에 유의한 차이가 없었다. 주사 바늘로 적용한 군과 paper point로 적용한 군 사이에도 평균 미세누출량에 유의한 차이가 없었다. 상아질과 근관 sealer계면의 주사전자현미경 관찰 결과 일부분에서 긴밀한 접착 관계를 나타내었고, 다른 부분에서는 간극을 나타내었다.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.257-266
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• 2010

The purpose of this study was to determine the effect of post types and sizes on fracture resistance in immature tooth model with various restorative techniques. Bovine incisors were sectioned 8 mm above and 12 mm below the cementoenamel junction to simulate immature tooth model. To compare various post-and-core restorations, canals were restored with gutta-percha and resin core, or reinforced dentin wall with dual-cured resin composite, followed by placement of D.T. LIGHT-POST, ParaPost XT, and various sizes of EverStick Post individually. All of specimens were stored in the distilled water for 72 hours and underwent 6,000 thermal cycles. After simulation of periodontal ligament structure with polyether impression material, compressive load was applied at 45 degrees to the long axis of the specimen until fracture was occurred. Experimental groups reinforced with post and composite resin were shown significantly higher fracture strength than gutta-percha group without post placement (p < 0.05). Most specimens fractured limited to cervical third of roots. Post types did not influence on fracture resistance and fracture level significantly when cement space was filled with dual-cured resin composite. In addition, no statistically significant differences were seen between customized and standardized glass fiber posts, which cement spaces were filled with resin cement or composite resin individually. Therefore, root reinforcement procedures as above in immature teeth improved fracture resistance regardless of post types and sizes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1566-1571
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• 2005

Consumer's perception and consumption pattern of fresh-cut agri-food Products were surveyed to Provide basic information for quality enhancement. The results are summarized as follows: The respondents had a preference for a discount store (60.5$\%$) to purchase fruits and vegetables and the frequency of purchase was one time Per week (46.1$\%$). Fruits and vegetables were purchased frequently by full-time housewives compared with workers. The reasons for purchasing fresh-cut agri-food generally resulted from a consideration of the saving in cooking time, the ease of handling and the desire to serve appropriate portions. On the other hand, the reasons for not purchasing fresh-cut agri-food Products were the comparatively high price, a perception of unsanitary handling. Freshness was considered to be the most important factor when purchasing these products. The preferred price for the fresh-cut agri-food products were approximately 110 $\∼$ 140$\%$ of that for the unprocessed products. 87.7$\%$ of respondents answered that they will purchase fresh-cut agri-food products continuously if some problems that they considered, would be improved.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.3-3
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• 2009

선박의 건조과정에서 필수적으로 선체 외판에는 선박의 안전과 운항 및 정비 등에 필요한 정보를 나타내기 위해 다양한 종류의 마크 및 문자가 마킹되어진다. 하지만, 단순한 도장 작업만으로는 해상과 같은 부식 환경에서 마크 및 문자가 쉽게 지워지거나 손상되기 때문에 마크 및 문자를 용접 비드(welding bead)로 표시하거나 미리 절단된 강판(steel plate)을 수동으로 용접한 뒤 도장을 함으로써 마크 및 문자의 손상을 방지하고 있다. 이러한 문자마킹작업을 하기 위해서는 작업자가 수작업으로 기준선과 마크 및 문자의 위치를 먹줄 등을 이용하여 마킹을 하고, 해당 마크 및 문자의 템플렛(template)을 이용하여 펀칭을 실시한 후 수동으로 용접을 실시한다. 하지만, 수작업을 통한 선체외판 문자마킹 작업은 작업자의 기량에 따라 품질이 상이하여 품질 저하의 원인이 된다. 또한 대조립 및 탑재 단계에서 문자 마킹 작업시 수직자세의 용접을 요구함으로써 작업자가 안전사고에 노출되어 있으며, 선박의 각 단계별 주요 공정보다 작업시간이 길어져 전체 선박 건조공정을 지연시키는 문제점 등을 야기시킬 수 있다. 이러한 문제점들을 해결하기 위해 조선업계에서는 선체 외판의 마크 및 문자를 자동으로 용접할 수 있는 장치를 개발하기 위해 노력해왔으며, 몇몇 개발 사례가 보고되고 있다. 하지만, 그 실효성 부분에서는 아직까지 해결하지 못한 문제점들로 인해 현장 적용에는 어려움을 보이고 있다. 본 연구에서는 선박외판 문자 자동용접장치의 기능성뿐만 아니라 현업 적용성을 가장 우선적으로 고려하여 문자마킹장치(Marking Robot for Shipbuilding) 개발을 진행하였다. 우선, 적절한 용접 재료를 선정하기 위해서 솔리드 와이어(Solid Wire)와 플럭스 코어드 와이어(Flux Cored Wire)에 대한 비드온 용접(Bead-On Welding)을 아래보기자세와 수직자세에 대해서 실시하여 적절한 용접 조건을 설정하였다. 본 연구에서 개발된 문자마킹 자동용접장치는 3축으로 구성되어 있으며 각 축들을 분리할 수 있도록 개발하여 이동성을 향상시켰으며, 작업면과 용접토치간의 거리를 일정하게 유지시킬 수 있도록 용접전류 센서(Welding Current Sensor)를 이용하여 토치 높이(Wire Extension)를 제어함으로써 균일한 품질의 용접비드를 얻을 수 있었다. 또한 문자마킹 자동용접장치는 본체 구동부와 제어부(Touch Screen)가 쉽게 분리되고 장착이 가능한 구조로 개발되었으며, 용접시 각 용접자세별로 용접전압, 전류 그리고 용접속도 설정이 가능하여 아래보기 자세뿐만 아니라 어떠한 자세에서도 같은 모양의 비드형상을 가지는 문자마킹용접이 가능하도록 개발하였으며, 이는 실험과 현장적용을 통해 검증하였다.