• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.20-20
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• 2011

It has been known that, under certain conditions, application of low-temperature atmospheric-pressure plasmas can enhance proliferation of cells. In this study, conditions for optimal cell proliferation were examined for various cells relevant for orthopaedic applications. Plasmas used in our experiments were generated by dielectric barrier discharge (DBD) with a helium flow (of approximately 3 litter/min) into ambient air at atmospheric pressure by a 10 kV~20 kHz power supply. Such plasmas were directly applied to a medium, in which cells of interest were cultured. The cells examined in this study were human synoviocytes, rat mesenchymal stem cells derived from bone marrow or adipose tissue, a mouse osteoblastic cell line (MC3T3-E1), a mouse embryonic mesenchymal cell line (C3H-10T1/2), human osteosarcoma cells (HOS), a mouse myoblast cell line (C2C12), and rat Schwann cells. Since cell proliferation can be enhanced even if the cells are not directly exposed to plasmas but cultured in a medium that is pre-treated by plasma application, it is surmised that long-life free radicals generated in the medium by plasma application stimulate cell proliferation if their densities are appropriate. The level of free radical generation in the medium was examined by dROMs tests and correlation between cell proliferation and oxidative stress was observed. Other applications of plasma medicine in orthopaedics, such as plasma modification of artificial bones and wound healing effects by direct plasma application for mouse models, will be also discussed. The work has been done in collaboration with Prof. H. Yoshikawa and his group members at the School of Medicine, Osaka University.

• 한국균학회지
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• 제27권4호통권91호
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• pp.243-248
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• 1999

야생에서 Cordyceps militaris를 채집하여 실험실에서 균을 분리하였으며, 형태적, 배양적 특징 및 인공자실체 형성조건에 관하며 몇 가지 실험을 하였다. 인공자실체에 형성된 C. militaris의 자좌는 곤봉형 또는 막대 형태로 야생에서와 같이 오랜지색을 띄었다. 자좌에 형성된 자낭각은 달걀모양으로 반나생 하며, 크기는 $30{\sim}90{\times}90{\sim}130\;{\mu}m$로 원주상의 자낭과 장방추형의 자낭포자를 가지고 있었다. C. militaris의 불완전 세대는 구형이나 땅콩모양의 분생포자를 형성하며, PDA 배지에서 양모상으로 중앙 융기한다. 인공자실체 형성조건에 관하며 배양용기로는 생육일수가 빠르고, 발이율과 수량이 높은 PP 배양병이 적당하였으며, 조명도는 1,000 lx에서 자실체 생육이 우수한 결과를 얻었다. 자실체 행성에 적합한 염가의 배지는 누에 번데기 보다 쌀보리, 밀과 현미 등의 곡물배지이며, 자실체 형성을 위해 종균제조에 사용되는 균주는 3회 이상 계대배양 할 경우 급격한 수량 감소의 요인으로 작용하였다.

• 식물조직배양학회지
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• 제27권3호
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• pp.185-189
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• 2000

카사바 (Manihot esculenta Crantz, cv. MCol 22)의 마디 절편을 MS 기본배지에 3종류의 사이토키닌을 여러 농도로 첨가한 조건에서 2주동안 현탁배양한 결과, 고체배지에서 3주 배양된 것보다 훨씬 생장이 효과적이었다. 현탁배양된 유식물에서는 과수화현상이 나타났으나, 이들을 세사 (마사토 + 1/2농도의 크놉씨액)를 담은 유리배양병에 이식하여 생육시킨 결과, 유경에서 새 잎이 신장되면서 과수화를 벗어나 4주후에는 4~6개의 마디를 가진 유경길이 3~5 cm의 정상 유묘로 생장됨으로서, 목본식물인 카사바의 경우 마디절편의 현탁배양에 의한 대량증식의 가능성을 확인했다. 현탁배양시 저농도의 제아틴 (0.01-0.05 mg 1$^{-1}$) 처리는 BAP 최적조건에서 보다 2배나 길게 부정아 길이를 신장시켰다. 사이토키닌 처리로 부정아가 잘 발생된 유식물은 토양이식 작업을 간편하게 했으며, 토양 이식 후 부정근을 활발히 발생시켜 one step culture시스템 배양이 가능하게 했다. 과수화된 유식물은 기외에서 순화가 어려웠으나 유기물이 혼입되지 않은 세사를 담은 유리배양병에서는 비무균조건일지라도 95% 이상 순화될 수 있었다.

• 한국수정란이식학회지
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• 제11권3호
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• pp.301-307
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• 1996

This study was carried out to produce twin calves by embryo transfer in Hanwoo and investigate the pregnancy and twin rate by recipient's conditions. All recipients were bred at estrus by artificial insemination with Hanwoo semen and then transfered an additional embryo produced in vivo or in vitro to tbe uterine horn contralateral to the corpus luteum on Day 7. The results obtained were as follows ; 1. The pregnancy rate was higher in young recipients of 3 years (68.8%) than in old ones of 10 years and greater(36.4%). And for CL size pregnancy rate was 57.9, 45.4 and 60.1% in large, medium and small size of CL of recipients, respectively. 2. 447recipients were transferred an additional embryos at 7th day after Al and average pregnancy rate was 57.5% and twin production rate was 22.2%. 3. Average pregnancy and twin production rate by direct transfer methods of frozenthawed IVF embryos was 56.0 and 16.7%. 4. The ratio of male to female twin in a total of 55 twin pairs was 54.6%, and average gestation lengths of male to female and female to female twin were 280.6$\pm$5.4 and 279.715.4 days, respectively. Average birth weight of twins was beavior in male and male twin(23.2i5.8kg) than in male and female twin(20.5$\pm$2.6kg).

• Journal of Plant Biotechnology
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• 제1권1호
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• pp.31-38
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• 1999

An artificial symbiosis was established between diazotropic Azomonas insignis and strawberry (Fragaria x ananassa). The partnership was created by in vitro techniques through callus induction and organogenesis. The basis of this partnerships is the bacterial dependence on the plants metabolic activity, using maltose in the medium as a carbon and energy source which can be utilized by the plant cells only. The presence of bacteria in the intercellular spaces of the callus tissues and regenerated plants was proven by microscopic techniques. Nitrogenase activity could also be detected in the plant tissues. For successful and high frequency introduction of bacteria to the plant tissues, biolistic gun method was used. On the basis of the DNA transfer method, Azotobacter vinelandii bacteria were delivered directly into strawberry tissues by the particle bombardment. This was the first use of living bacteria as microprojectils for bombardment of plant tissues. The treatment was successful, the presence of bacteria in the developing callus tissue and regenerated plants were detected by light and electron microscopy.

• Computers and Concrete
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• 제21권1호
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• pp.21-30
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• 2018

In this study, we analyze the behavior of concrete which contains zeolite and diatomite. In order to achieve the goal, we utilize expert system methods. The utilized methods are artificial neural network and adaptive network-based fuzzy inference systems. In this respect, we exploit seven different mixes of concrete. The concrete mixes contain zeolite, diatomite, mixture of zeolite and diatomite. All seven concrete mixes are exposed to 28, 56 and 90 days' compressive strength experiments with 63 specimens. The results of the compressive strength experiments are used as input data during the training and testing of expert system methods. In terms of artificial neural network and adaptive network-based fuzzy models, data format comprises seven input parameters, which are; the age of samples (days), amount of Portland cement, zeolite, diatomite, aggregate, water and hyper plasticizer. On the other hand, the output parameter is defined as the compressive strength of concrete. In the models, training and testing results have concluded that both expert system model yield thrilling medium to predict the compressive strength of concrete containing zeolite and diatomite.

• 식물조직배양학회지
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• 제21권3호
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• pp.183-186
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• 1994

태백벼의 현탁배양세포주로부터 유도된 체세포배를 낱개로 알진산 캡슐화하여 인공종자화하였다. 인공종자는 1/2 MS 고체배지에서 73%의 발아율을 나타내었으며 알진산 캡슐은 체세포배의 발아율에 영향을 주지 않았다. 그러나 멸균되지 않은 여과지에서는 발아율이 60%로 낮아졌다. 캡슐화된 진정종자는 무균상태여부에 관계없이 높은 발아율을 나타내었다. 이상의 결과로 무균상태가 유지되지 않을 때 인공종자 발아율이 낮아지는 것은 체세포배가 진정종자의 접합자배보다 오염을 견디기 어렵기 때문인 것으로 사료된다.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.397-401
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• 2011

The response of lightning impulse voltage was explored in dielectric liquids employing hydrodynamic modeling with three charge carriers using the finite element method. To understand the physical behavior of discharge phenomena in dielectric liquids, the response of step voltage has been extensively studied recently using numerical techniques. That of lightning impulse voltage, however, has rarely been investigated in technical literature. Therefore, in this paper, we tested impulse response with a tip-sphere electrode which is explained in IEC standard #60897 in detail. Electric field-dependent molecular ionization is a common term for the breakdown process, so two ionization factors were tested and compared for selecting a suitable coefficient with the lightning impulse voltage. To stabilize our numerical setup, the artificial diffusion technique was adopted, and finer mesh segmentation was generated along with the axial axis. We found that the velocity from the numerical result agrees with that from the experimental result on lightning impulse breakdown testing in the literature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.293-296
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• 1998

Surface electrical conduction in insulator is most important factor to assess the insulation performances of outdoor insulating materials. In this paper, contamination performance of the widely used materials for outdoor insulator - porcelain, EPDM, Silicone rubber - were discussed by measuring properties of average leakage current and scintillation discharge pulses under artificial contamination conditions. The artificial contaminations used were deionized distilled water fog, 0.5wt% NaCl salt fog of light pollution and 2wt% NaCl salt fog of medium pollution. The average leakage current was appeared linearly with applied voltage at dry and clean surface condition. The magnitude of leakage current was almost same at different kinds of samples. In case of deionized distilled water fog, the characteristics of leakage current and applied voltage was most different to that in case of dry and clean condition. In case of salt fog pollution condition, The leakage current was increased above critical voltage. The scintillation discharges were also activated at the level. the leakage current and scintillation discharges were increased with increasing pollution degree. The resistance to pollution properties of silicone rubber appeared excellent among them.

• BMB Reports
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• 제40권1호
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• pp.53-57
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• 2007

The enzymatic properties of NADH:quinone oxidoreductase were examined in Triton X-100 extracts of Bacillus cereus membranes by using the artificial electron acceptors ubiquinone-1 and menadione. Membranes were prepared from B. cereus KCTC 3674 grown aerobically on a complex medium and oxidized with NADH exclusively, whereas deamino-NADH was determined to be poorly oxidized. The NADH oxidase activity was lost completely by solubilization of the membranes with Triton X-100. However, by using the artificial electron acceptors ubiquinone-1 and menadione, NADH oxidation could be observed. The activities of NADH:ubiquinone-1 and NADH:menadione oxidoreductase were enhanced approximately 8-fold and 4-fold, respectively, from the Triton X-100 extracted membranes. The maximum activity of FAD-dependent NADH:ubiquinone-1 oxidoreductase was obtained at about pH 6.0 in the presence of 0.1M NaCl, while the maximum activity of FAD-dependent NADH:menadione oxidoreductase was obtained at about pH 8.0 in the presence of 0.1M NaCl. The activities of the NADH:ubiquinone-1 and NADH:menadione oxidoreductase were very resistant to such respiratory chain inhibitors as rotenone, capsaicin, and $AgNO_3$, whereas these activities were sensitive to 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO). Based on these results, we suggest that the aerobic respiratory chain-linked NADH oxidase system of B. cereus KCTC 3674 possesses an HQNO-sensitive NADH:quinone oxidoreductase that lacks an energy coupling site containing FAD as a cofactor.