• 미생물학회지
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• 제37권3호
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• pp.234-238
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• 2001

배추김치와 부추김치의 발효양상을 비교하기 위해 $20^{\circ}C$와 $10^{\circ}C$로 나누어 발효과정 중의 총 균수, 젖산균 수, pH 및 총 당함량을 비교 분석하였다. $20^{\circ}C$에서 발효한 배추김치의 경우 총 균수와 Leuconastoc속과 Lactobacillus속 젖산균 모두 발효 초기인 2일째에 최대에 도달하다가 그 이후에는 점점 감소하였다. 그러나 $20^{\circ}C$에서 발효한 부추김치의 경우에는 Leucanostoc속은 발효 3일째에 최대에 도달한 후 점차 감소하였지만 Lactobacillus속은 발효 15일 이후까지 그 균수가 유지되었다. $10^{\circ}C$에서 발효한 경우에는 배추김치, 부추김치 모두 $20^{\circ}C$에서 발효한 경우보다 Leuconostoc속과 Lactobacillus 속의 균수가 서서히 중가하다가 감소하였다. pH 변화는 배추김치 경우에는 3일 후에 적숙기 김치의 pH인 4.2 부근에 도달한 후 발효 5일째에 3.5 까지 낮아져 그 후에도 계속 유지되었으나 부추김치의 경우에는 발효 10일째까지 적숙기 김치의 pH인 4.2 이상으로 유지되었다. $10^{\circ}C$의 경우 배추김치는 6일 후 pH 4.2 정도였으나 부추김치는 24일 후에도 pH 4.2 이상으로 유지하였다. 발효 기간에 따른 총 환원당의 함량은 배추김치와 부추김치 모두에서 발효초기부터 발효가 진행됨에 따라 계속적으로 감소하였지만 $10^{\circ}C$에서 발효한 부추김치의 경우에는 감소정도가 매우 완만하였다. 이상의 결과로부터 부추김치가 배추김치보다 젖산균의 종식이 더디어 배추김치에 비해 발효가 서서히 진행됨을 알았다.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.8-13
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• 1998

Animal cells in culture typically convert most of the glucose they consume into lactate. The accumulation of lactate, however, is commonly cited as one of the factors that inhibit cell growth and limit the maximum cell concentration that can be achieved in culture. The specific production of lactate and the amount of glucose converted to lactate can be reduced when cells are grown in a fed-batch culture in which the residual glucose concentration is maintained at low levels. Such a fed-batch culture was used to grow and adapt hybridoma cells into a low-lactate-producing state before changing into continuous culture. The cells reached and maintained a high viable cell concentration at steady state. In a similar manner, cells that were initially grown in batch culture and a glucose-rich environment reached a steady state with a cell concentration that is much lower. The feed composition and dilution rates for both cultures were similar, suggesting steady state multiplicity. From a processing perspective the desired steady state among those is the one with the least metabolite production. At such seady state nutrient concentration in the feed can be further increased to increase cell and product concentrations without causing the metabolite inhibitory effect typically seen in a cell culture. Controlling cell metabolism in a continuous culture to reduce or eliminate waste metabolite production may significantly improve the productivity of mammalian cell culture processes.

• 치과방사선
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• 제25권2호
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• pp.331-341
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• 1995

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. For this study, cell surviving curves were obtained for murine melanoma Bl6 cell line using semiautomated M1T assay. 2,4,6,8, 10Gy were irradiated at a dose rate of 210cGy/min using /sup 60/Co Irradiator ALOORADO 8. After irradiatior, B16 cell lines(2.5×10⁴ cells/ml) were exposed to bleomycin and cisplatin at concentration of 0.2㎍/㎖, 2㎍/㎖ and 20㎍/㎖ for I hour respectively. The viable cells were determined for each radiation dose and/or each concentration of drug. And they were compared to control values. The obtained results were as follows : 1. There was significant difference of surviving fraction at 4, 6, 8, 10Gy on B16 cell line(P<0.05). 2. There was significant difference of cytotoxicity between bleomycin and cisplatin at concentration of 0.2㎍/㎖ and 2㎍/㎖(P<0.05) on B16 cell line, but there was no significant difference of cytotoxicity at concentration of 20㎍/㎖ on B16 cell line. 3. There was significant difference of cytotoxicity of bleomycin after irradiation of 2Gy and 10Gy on B16 cell line(P<0.01). 4. There was significant difference of cytotoxicity of cisplatin at concentration of 20㎍/㎖ after irradiation on B16 cell line.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.123.1-123.1
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• 2010

The solid oxide fuel cell (SOFC) has attracted great deal of attention due to its high electrical efficiency, high waste-heat utilization, fuel flexibility, and application versatility. However, SOFC technology is still not matured enough to fulfill the practical requirements for commercialization. Therefore, all the research and development activities are mainly focused on a development of practically viable SOFCs with higher performance and better reliability. We were successful in fabricating high-performance anode-supported unit cells by employing hierarchically controlled multi-layered electrodes for both structural reliability and high performance. In addition, a novel composite sealing gasket made it possible to achieve excellent sealing integrity even with considerable surface irregularities in a multi-cell planar arrayed stack.

• Journal of Chest Surgery
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• 제43권6호
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• pp.833-837
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• 2010

이 보고는 고환종자세포암 치료 후 폐전이를 폐절제술을 시행하여 성공적으로 치료한 증례이다. 항암치료 후 양전자방출단층촬영상 FDG의 유의한 섭취는 없었고 잔존종양을 원발 병소와 조직학적 비교를 위해 전이암을 제거하였다. 본 증례는 잔존종양에 생존세포가 관찰되지 않아 부가적인 항암치료는 시행하지 않았으며, 현재 술 후 6개월로 현재 재발이나 합병증 없이 잘 지내고 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.689-696
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• 2001

Exergetic and thermoeconomic analysis were performed for a 200kW Phosphoric Acid Fuel Cell(PAFC) plant which offers many advantage for cogeneration in the aspect of high electrical efficiency and low emission. This analytical study was based on the data obtained by in-field measurement of PC25 fuel cell plant to find whether this system is viable economically. For 100% load condition, the electrical efficiency and the unit cost of electricity are about 45% and 0.032 $/kWh respectively, which turn out to be much better than those for the 1000kW gas turbine cogeneration plant. Further, at lower loads, the unit costs of electricity and hot water increase slightly and consequently more economic operation is possible at any loads.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.102-105
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• 1997

In cultivating human neuroblastoma cells maximum number of neurites per cell and length of the neurite were estimated as 5.5 and 2.2 (nm), respectively It was found that there was correlation between growth and differentiation of nerve cells. Maximum specific BDNF production rate was also calculated as 2.5$\times $10$^{-5}$(ng/cell/day) at 7$\times $ 10$^{5}$ (viable cells/ml) of maximum cell density, corresponding to 100 (ng/mL) of BDNF. The secretion of BDNF was occurred most in the later peroids of the cultivation, yielding 75 (ng/mL) of BDNF. The production of rate of BDNF was elongated in adding 1 ($\mu $g/mL) of BDNF as well as 40% increase of the length of the BDNF. It proves that BDNF can be used as one of biopharmaceuticals to treat age-related diseases such as Alzheimer's disease and Prakinson's disease. It can also provide the information of scaling-up mammalian cell cuture system to economically produce BDNF.

• 한국미생물·생명공학회지
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• 제21권2호
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• pp.176-180
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• 1993

Survival and heat resistance of Listeria monocytogenes Scott A in various nutritional environments and cell type on stainless steel were determined. Viable cell of L. monocytogenes Scott A was most rapidly decreased in phosphate buffer among various media such as NSM (30 g TSB/1 l D.W.), LNM (2 g TSB/1 l D.W.) and phosphate buffer (pH=7) during incubation at 21 and 35C but survived for 15 days at 21C. Vegetative and starved L. monocytogenes Scott A were survived after heat treatment for 5 min at 65C while not detected at 72C.

• 한국식품영양과학회지
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• 제28권4호
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• pp.805-809
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• 1999

The growth of Lactobacillus casei in milk was enhanced by adding yams. Addition of 1% yam(raw or dry) promoted the cell growth and acid production in fermented milk. The milk containing 1% yams formed the complete curd by lactic acid fermentation at 37oC for 19hr while the milk without yams showed the incomplete curd formation. The crude mucilage extracted from a raw yam also enhanced the cell growth as well as the acid production. Addition of mucilage(0.08%) showed the similar effects with adding heat treated yam(1%). The milk fermented by adding various yams showed the high scores for sensory evaluation comparing with the milk fermented without yams. The fermenting ability of Lactobacillus acidophilus, Lactobacillus kefir and Leuconostoc mesenteroides was evaluated by adding 1% of a dry yam in milk. A dry yam also enhanced the cell growth of L. acidophilus resulting in the high acid production. The viable cell counts of L. casei, L. acidophilus and Leuc. mesenteroides except L. kefir were increased by adding 1% of a dry yam.

• The Plant Pathology Journal
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• 제29권4호
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• pp.374-385
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• 2013

Environmental stresses induce several plant pathogenic bacteria into a viable but nonculturable (VBNC) state, but the basis for VBNC is largely uncharacterized. We investigated the physiology and morphology of the copper-induced VBNC state in the plant pathogen Ralstonia solanacearum in liquid microcosm. Supplementation of $200{\mu}M$ copper sulfate to the liquid microcosm completely suppressed bacterial colony formation on culture media; however, LIVE/DEAD BacLight bacterial viability staining showed that the bacterial cells maintained viability, and that the viable cells contain higher level of DNA. Based on electron microscopic observations, the bacterial cells in the VBNC state were unchanged in size, but heavily aggregated and surrounded by an unknown extracellular material. Cellular ribosome contents, however, were less, resulting in a reduction of the total RNA in VBNC cells. Proteome comparison and reverse transcription PCR analysis showed that the Dps protein production was up-regulated at the transcriptional level and that 2 catalases/peroxidases were present at lower level in VBNC cells. Cell aggregation and elevated levels of Dps protein are typical oxidative stress responses. $H_2O_2$ levels also increased in VBNC cells, which could result if catalase/peroxidase levels are reduced. Some of phenotypic changes in VBNC cells of R. solanacearum could be an oxidative stress response due to $H_2O_2$ accumulation. This report is the first of the distinct phenotypic changes in cells of R. solanacearum in the VBNC state.