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유기용매 추출법에 의한 포플라의 전처리 및 당화 조건의 최적화
박정극,전영삼 東國大學校 1990 論文集 Vol.29 No.-
The effect of the pretreatment by solvent extraction with various solvent on the saccharification of poplar (Populus euramericana)was studied. The solvent system was phenol/H_2O (uncatalyzed, HCl and NaOH catalyzed), butanol/H_2O, ethanol/H_2O and ethylendiamine/H_2O solvent system. When the poplar was pretreated by phenol/H_2O uncatalyzed system, the best result of the enzymatic saccharification was total of 43.87 g/L reducing sugar produced and 83.35% of carbohydrated conversion was obatined at 190℃, 60 minutes. Total wood yield and the lignin removal were 46.3% and 96.17%, respectively. The use of acid, base catalyst and the others solvents was unsuitable to increase the efficiency of saccharification.
박정극,윤희훈,양은경 동국대학교 산업기술연구원 1999 산업기술논문집 Vol.14 No.-
본 논문에서는 화학물질의 안전성평가를 위한 동물실험의 대안으로서 피부에 대한 자극성 시험에 조직공학적으로 재구성한 인공피부를 이용하고자 하였다. 자극성물질로서 glutaraldehyde, toluene, sodium lauryl sulfate, 그리고 비자극성물질로서 polyethylene glycol 등을 사용하여 단층으로 배양된 피부세포와 제조된 진피조직, 그리고 제조된 인공피부에 노출시켰다. 이에 대한 인공피부의 독성 반응은 MTT전환율, interleukin-1α(IL-1α), 그리고 hydroxyeicosatetraenoic acid(HETE) 생성량을 지표로 하여 검사한 결과, 인공피부의 MTT전환율이 세포의 단층배양과 진피조직의 경우보다 더 높게 나타났다. 전염증성 조절인자인 interleukin-1α와 HETE 생성량의 검사결과에서도 전층 인공피부가 시험물질에 대한 저항성이 더 높은 것으로 나타났으며, 이는 인공피부가 실제피부와 같이 중층화된 표피를 지니므로 시험물질의 국소적 노출이 가능하고 시험물질의 흡수 및 분산 효과를 유지할 수 있어 실제 피부에 대한 현실적인 모델이 됨을 보여주고 있다. We examined toxicological responses of artificial skin using MTT conversion, interleukin-1α and hydroxyeicosatetraenoic acid productions when it was exposed to glutaraldehyde, toluene, sodium lauryl sulfate known as irritants and polyethylene glycol known as non-irritant. Artificial skin showed higher MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) conversion than those of monolayer and dermal equivalent. Interleukin-1α productions had reasonable difference between dermal equivalent and artificial skin in respect to tendency. Dermal equivalent had maximum production of interleukin-1α at 0.4% concentration of sodium lauryl sulfate, while it was 1.0% in the case of artificial skin. It suggests that artificial skin is more resistant to toxicant and can be a good in vitro model system to mimic the natural skin.
박정극,송계용,권순용,Kyung-Min Choi,Young-Kwon Seo,윤희훈,Hwa-Sung Lee 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.6
To support and enhance the in vitro growth and activity of mesenchymal stem cells (MSCs), the cell culture medium may be supplemented with various proteins and factors to mimic the physiological environment in which the cells optimally proliferate and differentiate. In this study, the effects of mechanical factors on cellular metabolic responses were investigated experimentally using a bioreactor. The effects of various chemical factors, such as growth factors, cytokines, and hormones, were also investigated. Based on previous reports demonstrating the important roles of mechanical factors in the growth and activity of MSCs, we sought to evaluate the effects of mechanical stimuli on the proliferation of bone marrow-derived MSCs using a cell training bioreactor that imposed cyclic mechanical stretch, with parameters of 240 min/day, 0.03 Hz, and 5~15% strain. The application of cyclic stretch (5~15% strain) to the MSCs enhanced their proliferation during the early stage (3 days), but not the late stage (14 days), of batch culture. Mechanical stretch did not increase the release of lactate dehydrogenase (LDH) from the MSCs during culture. Appropriate levels of mechanical stretch (5~10% strain) increased collagen synthesis, but did not alter MSC surface antigen expression. It is thought that the appropriate level of mechanical stretch was able to serve as a potent positive modulator of MSC proliferation during the initial stages of culture.
산소전달계수 및 경험적 기질공급방법이 Baker's Yeast 의 유가식배양에 미치는 영향
박정극,윤문영 한국화학공학회 1999 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.37 No.1
Baker's yeast 유가식배양에서 최적의 수율과 생산성을 위하여 K_La(산소전달계수)와 3가지 경험적 기질공급방법의 영향을 조사하였다. 발효기내의 교반속도(100에서 600rpm)와 통기속도(1.0, 1.5, 2.0vvm)를 변화시키면서 K_La값을 측정하였고, 통기속도는 1.5vvm으로 일정하게 유지하고 각각의 교반속도(300에서 600rpm)에서 유가식배양을 실시하여 수율과 생산성을 조사하였다. K_La값은 교반속도와 통기속도에 비례하여 빠르게 증가하였다. 기질공급 pattern은 sigmoidal한 공급이 최적으로 나타났고, 최적의 총 기질공급량과 생산성은 K_La값에 크게 의존하였으나 500rpm부터는 일정한 값을 유지하였고, 수율을 K_La값이 증가함에 따라 약간씩 감소하는 경향을 나타냈다. 이것은 molasses 투입량 증가에 의한 molasses내에 존재하는 저해작용물질축적과 발효대사산물의 축적, 점도의 증가, cell농도의 증가 등에 의해 cell 성장속도와 산소전달속도가 감소한 것으로 사료되고, 본 발효기는 500에서 600rpm부근에서 운전하는 것이 최적조건으로 판단된다. The effect of K_La(Oxygen Transfer Coefficient) and substrate feeding policy on the optimum cell yield and productivity was investigated in the baker's yeast fed-batch cultivation. K_La was measured at various agitation speed(100 to 600 rpm) and aeration rate (1.0, 1.5, 2.0 vvm), and the cell yield and productivity of fed-batch cultivation was determined at each agitation speeds (300 to 600 rpm) and constant aeration rate (1.5 vvm). K_La value was increased proportionally with increasing agitation speeds and aeration rate. Substrate feeding pattern was optimum in sigmoidal feeding. The optimum total fed-sugar and productivity was largely dependent on the K_La and did not change at above 500rpm, and the cell yield was decreased gradually as the K_La increased. It is considered that the increase of the accumulation of inhibitory substances in the molasses by the increase of molasses feeding, the accumulation of fermentation metabolites, the viscosity and cell concentration of fermentation broth, and so forth was decreased the cell growth rate and oxygen transfer rate. So, the optimum operation condition of this fermentor was estimated to near 500 to 600 rpm.
빙축열 냉방시스템과 흡수식 냉온수기의 경제성 비교 : 생인공전피의 냉도보존 방법의 개발에 관한 연구
박정극,박재섭 동국대학교 산업기술연구원 2001 산업기술논문집 Vol.12 No.2
본 연구에서는 조직공학적으로 만든 생인공진피를 그들의 기능적 특성을 유지하면서 장기간 냉동보존할 수 있는 방법을 개발하고자 하였는데, 이를 위해 내동보존시 세포에 가장 중요한 영향을 주는 인자들을 지표로하여 살펴보았고 thiazolyl blue (MTT) 분석을 통하여 세포의 회복률을 평가하였다. 또한 냉동속도 정확하게 원하는 속도로 맞추기 위해서 냉동프로그램을 개발하여 조직의 냉동에 사용하였다. 결과적으로 생인공진피는 냉동보호용액의 노출온도가 낮을수록 그리고 냉각속도가 느릴수록 보다 높은 세포 생존율을 나타내었으며, -196℃의 저장온도에서는 조직이 형태학적으로 변형을 일으킨 반면 -130℃ 이상의 저장온도에서는 조직이 육안적으로 integrity를 완전하게 유지하였다는 사실을 관찰할 수 있었다. In this study, out efforts were made to develope the long-term cryopreservation method of tissue-engineered bioartificial dermal equivalent keeping his own biological function. For this purpose, we studied the primary factors exerting on cell recovery at cryopreservation and thiazolyl blue (MTT) assay was carried out to measure cell recovery. Also new freezing program used for cooling bioartificial dermal equivalent was set up to lower a temperature to -90℃ at cooling rate of 1℃/min. As a conclusion, it was found that cell recovery tended to increase as the exposure temperature of cryoprtectant solution was down, and the cooling rate became lower. It was also shown that the samples cryopreserved at -196℃ didn't retain their integrity but ones cryopreserved above -130℃ retained it. So, this fact implies that storage above -130℃ is the safe way fitted in cryopreserving bioartificial dermal equivalent.
박정극,김영진,송계용,유보영,Youn-Ho Shin,윤희훈,Sung-Joo Hwang 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.1
Hair follicle is a small but very complex and dynamic miniorgan of the human body. It is easy to isolate and culture mesenchymal cells but not epithelial cells of hair follicle. It is necessary for intact and healthy outer root sheath (ORS) cells to be isolated and cultured. In this study we developed an appropriate isolation method to yield 6.4 ± 0.75 × 104 cells/hair follicle, which is about 9-fold comparing to our previous data. This yield was achieved by modifications such as different kinds of enzyme uses, fragmentation, and mechanical stimuli. Especially we detected that the different kinds of isolation enzyme could affect proliferation of ORS cells during primary culture. In addition, bovine pituitary extract (BPE) was needed for ORS cells to proliferate and to form colonies under serum-free, feeder layer-free culture condition, but type I collagen as a substratum did not have any positive effect. Moreover, ORS cells under BPE-added condition contained stem/progenitor cells expressing β1-integrin, CK19, and CD34. These results can provide useful cell culture information, not only in the study of hair biology but also in the field of tissue engineering and cell therapy for the treatment of alopecia.