• 공학교육연구
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• 제13권1호
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• pp.17-22
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• 2010

이 논문에서는 공학소양교육의 사례로서 기술사의 연구성과를 활용하여 에디슨의 주요 활동과 그 의미를 검토하였다. 에디슨은 시스템 구축가로서 전등을 사용하는 데 필요한 모든 기술을 확보했으며, 전등의 상업화를 위한 활동도 포괄적으로 전개하였다. 이에 반해 직류와 교류 사이의 전류전쟁에서 에디슨은 새로운 기술에 완강하게 저항하는 모습을 보였다. 또한 에디슨은 축음기와 영화를 개발했지만 그것을 배경으로 성장한 대중문화를 이해하지 못했다. 이러한 연구는 그 자체로서 공학소양교육을 위한 콘텐츠를 제공해 줄 수 있을 뿐만 아니라 기술혁신의 역동적인 성격과 바람직한 기술자의 모습을 모색하는 데 도움을 줄 수 있다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.223-227
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• 2003

Mevinolic acid (MA), a secondary metabolite produced by a filamentous fungus Aspergillus terreus, is acidic form of lovastatin which has been identified as a powerful cholesterol-lowering agent in humans. When immobilized cell culture was performed, MA production was about 5.3-fold higher than the parallel suspended cell culture. Although the immobilized cells proliferated slowly during exponential in comparison with the suspended cells, oxygen uptake rate and oxygen mass transfer coefficient of the immobilized cell culture were about 1.3- and 2.5- fold higher respectively than those of the parallel suspended cell culture. From these results, it was concluded that MA biosynthesis was closely dependent on the cell growth rate, morphology and oxygen availability.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권2호
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• pp.146-149
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• 2000

Biologically active porcine Interleukin-2(poIL-2) was produced from in vitro and in viva baculovirus expression system, namely the Autographa californica nuclear polyhedrosis virus (ACNPV)-cell culture system and the Hybrid nucler polthedrosis virus (HyNPV)-sillkworm larva system. The concentration of the recombinant poIL-2(rpoIL-2) in the larvae hemolymph was 1 to 3 mg/mL, which was about 7 to 20 times those of the cell culture systems. The level of this expression efficiency is equal to that with transgenic livestock, secretion products in milk.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2000년도 국제심포지움
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• pp.9-9
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• 2000

The mammalian ovary has a large number of primordial and preantral follicles, which are a potential source of oocytes for the in vitro mass production of embryos. Several in vitro culture systems have been developed to support the growth and development of oocytes from mouse preantral follicles. Under the appropriate condition, meiotically incompetent oocytes from preantral follicles can grow to final size and complete nuclear maturation in vitro. Furthermore, the successful production of live young from in vitro grown and matured oocytes demonstrates that oocytes from preantral follicles are able to acquire full developmental capacity in vitro. However, the efficiency of in vitro production of embryos from mouse preantral follicles is still low. In farm animals as well as human, the growth of oocyte from preantral follicle to the meiotic competence stage has yet to be demonstrate. Therefore, further studies to improve the culture condition or to develope new culture system should be needed in the future. In addition, the visible progress in the establishment of the in vitro culture system for preantral follicles of farm animals and human could help to enlarge the populations of valuable agricultural, phamaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that jeopardize oocytes.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.751-756
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• 1999

For mass production of poly(3-hydroxybutyrate) (PHB), high cell density cultures of Ralstonia eutropha were carried out in 2.5-1 and 60-1 fermentors by two fed-batch culture techniques of nitrogen and phosphate limitation. When the nitrogen limitation technique was employed using both an on-line glucose monitoring and control system, a high concentration level of PHB (121g/l) was obtained in the small-scale fermentor of 2.5 1. However, the PHB concentration obtained in a large-scale fermentor of 60 1 only turned out to be 60g/l. In contrast, when another fed-batch culture technique of the phosphate-limitation employing dissolved oxygen (DO) stat glucose feeding was used, a large amount of PHB was successfully produced in both 60-1 and 2.5-1 fermentors. In a 2.5-1 fermentor, concentrations of PHB and cells obtained in 58 h were 175 and 210 g/l, respectively, which corresponded to the PHB productivity level of 3.02 g/l/h. In a 60-1 fermentor, a final cell concentration of 221 g/l and a PHB concentration of 180 g/l with PHB productivity level of 3.75 g/l/h were obtained in 48h. PHB content and yield from glucose were 81% and 0.38g PHB/g glucose, respectively. These data suggest that the phosphate limitation technique is more effective compared to nitrogen limitation in the mass production of PHB by R. eutropha of a large scale.

• 한국미생물·생명공학회지
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• 제21권4호
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• pp.348-353
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• 1993

The optimal conditions for operating a moving-aeration bioreactor were determined as 30rpm and 150 (ml/min) of air flow rate, which can yield ca. 7.3 (l/h)of maximum mass transfer coefficient. It was also found that the agitation speed played much much important role than air input rate in oxgen transfer into the medium. $2.6{\times}10^6$ (cells/ml) and 0.6 (ml/l) of maximum cell denisty and IL-2 production were observed in batch cultivation of IL-2 producing BHK cell line. 0.53 (mM/l/h) of oxygen uptake rate was also estimated. The performance of a moving-aeration bioreactor (specific growth rate and oxygen uptake rate, etc.) was superior to other culture systems, such as cell-life and static membrane aeration bioreactors. Ii must be useful to apply this reactor to many culture processes by improving structural limitations in scaling-up the system.

• 한국수산과학회지
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• 제31권1호
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• pp.139-142
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• 1998

미세 조류의 생장에는 적당한 영양염 이외에 온도, pH, 조도 및 $CO_2$ 공급 등을 필요로 한다. 이들 증식 속도에 영향을 미치는 인자를 고려한 대량 배양 시스템을 제작하고자, VT-PBR을 이용하여 국내 해수산 Chlorella sp.의 배양 조건을 검토하였다. 국립수산진흥원 남해수산연구소 충무분소에서 어민에게 공급하고 있는 Chlorella sp.의 배양 최적 조건은 온도 $20^{\circ}C$, 조도 6,0001ux, 공기 공급속도 0.56vvm, 그리고 $CO_2$ 공급속도는 0.028vvm였다.

• 한국언론정보학보
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• 제36권
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• pp.287-323
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• 2006

이 연구는 조직문화와 조직지원요소가 방송프로그램 제작단위인 팀 몰입에 영향을 주는 주요한 요소로 작용하고 있음을 실증적으로 분석하였다. 특히 조직문화 유형에 따라 조직지원요소 및 팀 몰입에 차별적인 영향을 미치고 있음을 구조방정식 모형을 이용해 밝혀내고자 하였다. 연구결과 조직문화 유형에 따라 조직지원요소 및 팀 몰입에 영향을 주는 경로 및 영향력에 차이가 있음을 확인할 수 있었다. 또한 보상평가요소를 제외하고는 교육훈련, 제작지원 등의 조직지원요소는 제작진의 몰입에 별다른 영향을 미치지 못했다. 이와 같은 결과는 방송 조직이 전략을 수립 집행함에 있어 제작진이 인식하고 있는 지배적인 조직문화 유형을 고려해야 보다 실효성을 높일 수 있음을 보여준 결과라 할 수 있다. 이밖에 현재의 교육훈련 프로그램과 제작지원 방식을 보완할 필요성이 있음을 확인할 수 있었다.

• Journal of Microbiology
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• 제45권2호
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• pp.122-127
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• 2007

Factors indicating culture status of two Spirulina platensis strains were monitored in a batch mode cultivation for 36 days. Changing mode in all factors showed a common turning point, indicating shift of cell or culture status. Mean biomass productivity was highly sustained until day 22, chlorophyll a concentration peaked on day 22, pH value was > 12 on day 22, coil number was abruptly shortened on day 22, and floating activity was sustained at greater than 79% after day 22, indicating that day 22 is a criterion reflecting phase-transfer in cell physiology in a batch culture system. Many of these changes may have been caused by increased pH, suggesting that pH control is essential for mass production of S. platensis. Fluctuations in floating activity were likely induced by the number of cellular gas vacuoles. Consequently, coil number per trichome and floating activity of S. platensis could readily act as simple indicators for determination of culture status or harvesting time of cells.

• Journal of Plant Biotechnology
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• 제4권1호
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• pp.23-27
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• 2002

To establish an in vitro mass production system of grape anthocyanin pigments through callus and cell suspension culture, the effects of nitrogen source and sucrose on fresh weight and anthocyanin production in cell suspension culture of 'Sheridan' grape level were studied. When the medium was devoid of $NO_3^-$, cell fresh weight was either remained stable (1% sucrose) or slightly decreased with culture time (2,3, and 4% sucrose). When $NH_4^-$ was lacking, 3% sucrose was most favorable for cell growth. When $NH_4^-$ was supplied as N source, the anthocyanin content of 2% sucrose containing medium was maintained 2 times higher than other levels till day 8 in culture, then that of 3 and 4% sucrose which peaked at day 12 thereafter. The anthocyanin content was low than $NO_3^-$-free media. Total anthocyanin content in $NH_4^-$-free medium was just about a half of that of $NH_4^+$ medium. Anthocyanin production of 2% sucrose in $NH_4^+$ medium was maintained about 3-fold till day 8, then decreased thereafter. In $NH_4^+$ medium, pH decreased gradually with final pH of 3.5 to 4.0, while pH in $NH_4^+$-free medium increased with final pH of 6.5 to 7.5.