• 한국식품저장유통학회지
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• 제23권2호
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• pp.275-282
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• 2016

본 연구는 4종의 별의별간(SS) 음료의 간보호 소재로서의 이용 가능성을 조사하고자 항산화능 평가, t-BHP 와 $CCl_4$로 산화적 손상 및 급성 간독성 유도한 in vitro, in vivo 모델을 활용하여 간보호능을 평가하였다. 실험결과, 별의별간 01~04는 $50{\mu}M$ vitamin C 와 유사한 항산화 효과를 나타내었다. HepG2 세포에 t-BHP로 산화 스트레스를 유도한 뒤 나타나는 세포독성에 대해 별의별간 01 및 04에서 농도 의존적인 세포 보호효과를 보였으며, ROS 생성 억제에서 별의별간 01, 03, 04에서 농도의존적인 억제를 나타내었다. 미나리가 혼합된 별의별간 04에 대한 급성 간손상 in vivo 모델을 활용하여 간보호능 검증 결과, 별의별간 04는 $CCl_4$로 증가된 혈중 ALT, AST의 유의적 감소, 간 조직중 증가된 MDA 함량 감소 및 감소된 GSH의 유의적 증가를 나타내었다. 또한, 혈청 및 간 조직에서 증가된 중성지방과 콜레스테롤을 유의적으로 감소시켰다. 이러한 결과를 종합하며, 별의별간 04는 in vitro 및 in vivo 모델에서 산화적 손상에 대해 간보호 효과를 나타내었다.

• 기술혁신학회지
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• 제22권3호
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• pp.382-415
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• 2019

본 연구는 수 위탁거래의 전속성이 수탁 중소벤처기업의 R&D투자, R&D인력, 외부 조직과 협력 범위, 특허출원건수, 신제품에 의한 매출 및 누적 매출성장률에 미치는 영향을 분석한다. 벤처기업정밀실태조사의 원자료를 이용하여 6,029개 중소벤처기업의 병합된 횡단면 데이터를 분석한 결과 첫째, 대기업 및 1 2차 협력업체와 전속거래를 하는 중소벤처기업의 R&D투자수준은 시장판매 중소벤처기업의 투자수준보다 낮음을 실증하였다. 둘째, 전속거래를 하는 중소벤처기업의 혁신활동, 즉 R&D인력 비율 및 외부 조직과 협력 제휴 범위는 시장판매하는 중소벤처기업에 비해 낮음을 확인하였다. 셋째, 전속거래를 하는 중소벤처기업의 혁신성과, 즉 특허출원건수, 신제품에 의한 매출비중, 누적매출성장률은 시장판매하는 중소벤처기업에 비해 모두 낮음을 검증하였다. 네 번째로 수탁 중소벤처기업이 위탁 대기업의 1 2차 협력업체와 전속거래를 하는 경우가 가치사슬 상위의 대기업과 전속거래를 하는 경우에 비해 혁신 투입, 활동, 성과의 모든 측면에서 낮은 성과를 보이고 있었다. 위탁대기업 또는 1 2차 협력업체와 전속거래여부는 중소벤처기업의 혁신프로세스를 전반적이고 체계적으로 약화시켜서 혁신을 통한 성장을 기대하기 어려운 일종의 시장 실패를 가져오므로 중소벤처기업의 혁신정책은 이를 반영하여 설계될 필요가 있다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 1998년도 가을 학술발표회 프로그램
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• pp.2-4
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• 1998

Proliferation of Nocardia amarae cells in activated sludge has often been associated with the generation of nuisance foams. Despite intense research activities in recent years to examine the causes and control of Nocardia foaming in activated sludge, the foaming continued to persist throughout the activated sludge treatment plants in United States. In addition to causing various operational problems to treatment processes, the presence of Nocardia may have secondary effects on the fate of heavy metals that are not well known. For example, for treatment plants facing more stringent metal removal requirements, potential metal removal by Nocardia cells in foaming activated sludge would be a welcome secondary effect. In contrast, with new viosolid disposal regulations in place (Code o( Federal Regulation No. 503), higher concentration of metals in biosolids from foaming activated sludge could create management problems. The goal of this research was to investigate the metal sorption property of Nocardia amarae cells grown in batch reactors and in chemostat reactors. Specific surface area and metal sorption characteristics of N. amarae cells harvested at various growth stages were compared. Three metals examined in this study were copper, cadmium and nickel. Nocardia amarae strain (SRWTP isolate) used in this study was obtained from the University of California at Berkeley. The pure culture was grown in 4L batch reactor containing mineral salt medium with sodium acetate as the sole carbon source. In order to quantify the sorption of heavy metal ions to N amarae cell surfaces, cells from the batch reactor were harvested, washed, and suspended in 30mL centrifuge tubes. Metal sorption studies were conducted at pH 7.0 and ionlc strength of 10-2M. The sorption Isotherm showed that the cells harvested from the stationary and endogenous growth phase exhibited significantly higher metal sorption capacity than the cells from the exponential phase. The sequence of preferential uptake of metals by N. amarae cells was Cu>Cd>Ni. The specific surFace area of Nocardia cells was determined by a dye adsorption method. N.amarae cells growing at ewponential phase had significantly less specific surface area than that of stationary phase, indicating that the lower metal sorption capacity of Nocardia cells growing at exponential phase may be due to the lower specific surface area. The growth conditions of Nocardia cells in continuous culture affect their cell surface properties, thereby governing the adsorption capacity of heavy metal. The comparison of dye sorption isotherms for Nocardia cells growing at various growth rates revealed that the cell surface area increased with increasing sludge age, indicating that the cell surface area is highly dependent on the steady-state growth rate. The highest specific surface area of 199m21g was obtained from N.amarae cell harvested at 0.33 day-1 of growth rate. This result suggests that growth condition not only alters the structure of Nocardia cell wall but also affects the surface area, thus yielding more binding sites of metal removal. After reaching the steady-state condition at dilution rate, metal adsorption isotherms were used to determine the equilibrium distributions of metals between aqueous and Nocardia cell surfaces. The metal sorption capacity of Nocardia biomass harvested from 0.33 day-1 of growth rate was significantly higher than that of cells harvested from 0.5- and 1-day-1 operation, indicatng that N.amarae cells with a lower growth rate have higher sorpion capacity. This result was in close agreement with the trend observed from the batch study. To evaluate the effect of Nocardia cells on the metal binding capacity of activated sludge, specific surface area and metal sorption capacity of the mixture of Nocardia pure cultures and activated sludge biomass were determined by a series of batch experiments. The higher levels of Nocardia cells in the Nocardia-activated sludge samples resulted in the higher specific surface area, explaining the higher metal sorption sites by the mixed luquor samples containing greater amounts on Nocardia cells. The effect of Nocardia cells on the metal sorption capacity of activated sludge was evaluated by spiking an activated sludge sample with various amounts of pre culture Nocardia cells. The results of the Langmuir isotherm model fitted to the metal sorption by various mixtures of Nocardia and activated sludge indicated that the mixture containing higher Nocardia levels had higher metal adsorption capacity than the mixture containing lower Nocardia levels. At Nocardia levels above 100mg/g VSS, the metal sorption capacity of activate sludge increased proportionally with the amount of Noeardia cells present in the mixed liquor, indicating that the presence of Nocardia may increase the viosorption capacity of activated sludge.