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장영복,정태영,차기철,정형근,김성헌,김동진,유익근 한국물환경학회 2004 한국물환경학회지 Vol.20 No.4
The characteristics of H₂ production from livestock wastewater were investigated through an anaerobic acid forming process using Clostridium beijerinckii and the photosynthetic process using Rhodobacter sphaeroides. The submerged separation membrane was installed in the acid forming reactor. The photosynthetic process is composed of two reactors(photosynthetic reactor 1 and photosynthetic reactor 2) which is connected continually. The removal rate of COD and the production of volatile fatty acid(VFA) in the acid forming process were approximately 50% and 1000㎎/ L, respectively. The 70% of COD in the effluent of acid forming process was removed through the photosynthetic process. The production of H₂ in the photosynthetic reactor 1 and 2 was 50 and 25mLH₂/gVFA_(COD), respectively. The values of Y in acid forming reactor, photosynthetic reactor 1 and 2 was 0.2263, 0.0601 and 0.0393, respectively. The acetic acid and butyric acid produced in acid forming process were converted to H₂ by photosynthetic bacteria.
Yoo, Ik-Keun,Chang, Ho-Nam,Lee, Eun-Gyo,Chang, Yong-Keun,Moon, Seung-Hyeon The Korean Society for Microbiology and Biotechnol 1996 Journal of microbiology and biotechnology Vol.6 No.6
Batch fermentations of lactic acid were performed with Lactobacillus casei to investigate the effect of pH on cell growth and production of lactic acid and by-products. Maximum productivity of lactic acid increased with increasing pH from 5.0 to 6.5, and the extent of D-lactate production was different at each pH. Acetate and D-lactate concentrations increased even after the complete consumption of glucose in the medium. While a pH range of 6.0-6.5 was optimal for cell growth and lactic acid production, superior results were achieved at pH 6.0 when both maximum lactic acid productivity and minimum by-product formation were considered.
연구논문 : Biological Aerated Filter에서 유입 질소농도에 따른 아질산화 특성
유익근 ( Ik Keun Yoo ) 한국물환경학회(구 한국수질보전학회) 2014 한국물환경학회지 Vol.30 No.1
The purpose of this study was to investigate the nitrification characteristics of biological aerated filter (BAF) packed with Ceramic media, especially focusing on nitrite build-up during nitrification. When increasing the nitrogen load above 1.63 kgNH4(+)-N/m3d, ammonium removal efficiency decreased to less than 60% and the nitrite ratio (NO2+-N/NOx-N) of higher than 75% was achieved due to the inhibitory free ammonia (FA, NH3-N) concentration and oxygen limitation. FA inhibition, however, is not recommended strategy to promote nitrite build-up since FA concentration in the reactor is coupled with decreased ammonium removal efficiency. Nitrite ratio in the effluent was also affected by aeration rate and influent ammonium concentration. Ammonium oxidation was enhanced at a higher aeration rate regardless of influent ammonium concentration but, the nitrite ratio was dependent on both aeration rate and influent ammonium concentration. While a higher nitrite ratio was obtained when BAFs were fed with 50 mgNH4(+)-N/L of influent, the nitrite ratio significantly decreased for a greater influent concentration of 200-300 mgNH4(+)-N/L. Taken together, aeration rate, influent ammonium concentration and FA concentrations kept in the BAF were found to be critical variables for nitrite accumulation in the BAF system.
전단 응력에 의해 유도되는 혈관내피세포 Hsp70 의 발현
유소영,김동익,이병봉,장준근 대한혈관외과학회 2001 Vascular Specialist International Vol.17 No.2
Purpose: Endothelial cells (Ecs) are exposed to continuous shear stress due to the blood flow. Heat shock protein (hsp) 70 is a well-known stress-response protein. The objective of this study is to investigate the expression of hsp70 in human umbilical vein endothelial cells induced by shear stress. Method: The pattern of hsp70 was investigated by the in vitro laminar flow system and its image was analyzed by PV-WAVE software program. The image of heat shock-induced hsp70 expression was analyzed and compared with that of shear stress-induced hsp70 expression. Result: Under the condition of shear stress produced by flow, the Ecs change their morphology and lineup along the flow direction. As to expression of flow stress-induced hsp70, it was accumulated in perinuclear region of endothelial cells, which is different from heat shock-induced hsp70 expression. Conclusion: Ecs alignment along the direction of the flow shear stress and changes their phenotype are due to the remodeling of the actin microfilaments. Perinuclear expression of hsp70 may play an important roles in this shear stress induced remodeling response.
유소영,박찬영,정석,김동익,이병붕,허세호,한동철,장준근 대한혈관외과학회 2002 Vascular Specialist International Vol.18 No.2
Purpose: The spreading, orientation, and chemotaxis the gradient of a chemoattractant of smooth muscle cells (SMCs) were studied on the micro-grooved substrata by the light, fluorescence and scanning electron microscopy. Method: Vertical-walled grooves were produced in silicon wafers by the micromachining technique. All grooves were 4~20㎛ deep and 10~80㎛ wide, SMCs were cultured on each microgroove and examined under stereo-microscope. Result: Cell clusters were markedly oriented by all the grooved substrata examined. Tim-lapse images acquired from CCD (Charge Coupled Device) showed that the grooves directed the migration of SMCs. There was no prominent difference in the migration speed of SMCs according to the grooves. All the cytoskeletal fibers were reoragnized in the same direction with grooves. Especially the alignments of microtubule and intermediate filaments were distinguished in the SMCs on the micro grooves. Conclusion: These results could be applied to the analysis of vascular restenosis and the development of artificial blood vessels.
유익근,장호남 한국산업미생물학회 1994 한국미생물·생명공학회지 Vol.22 No.3
젖산균의 회분식 발효를 통해 균체 성장 및 젖산 생산은, 생산되는 젖산에 의한 생산물 저해 현상과 배지 중의 복합질소원 농도, 이 두가지 요인에 크게 좌우됨을 확인했다. 따라서 이를 개선하기 위한 방법으로 균체 재순환에 의한 연속발효를 시도했으며 특히 기존의 균체 재순환 연구에 비해, 생산되는 젖산의 농도를 높이고자 했다. 포도당 100 g/ℓ, yeast extract 15 g/ℓ의 배지를 이용한 완전 균체 재순환 발효에서 균체 농도는 145 g/ℓ, 젖산 농도는 85 g/ℓ, 생산성은 73 g/hr까지 올라갔으며 이는 같은 농도의 yeast extract를 사용한 회분식 발효보다 균체 농도는 16배, 생산성은 23배 정도 높은 값이다. 또한 희석율을 0.2로 일정하게 유지시켰을 때 전체적으로 10일 이상 연속 조업할 수 있었고, 이때 젖산 농도는 70 g/ℓ 정도로 높게 유지되었다. 그러나 yeast extract 농도를 3 g/ℓ로 감소시켰을 때 균체 농도는 거의 정상상태를 보였지만 젖산 농도는 약간 감소하여 50∼55 g/ℓ의 값에서 유지되었다. 생산되는 젖산의 광학 특성을 검토해 봤을 때 포도당 제한에 의해 D-lactate의 비율이 늘어나는 것으로 생각되며, 따라서 포도당 제한이 안 걸리는 경우의 완전 균체 재순환 발효에서 D-lactate의 비율 증가는 없었다. 또한 D-lactate의 생성은 acetate 생성과 밀접한 관계가 있는 것으로 보인다. In batch cultures of Lactobacillus delbrueckii, cell growth and lactic acid production were affected by two main factors, inhibition by lactic acid and limitation by nutritional components. In order to increase the productivity significantly, a continuous stirred tank reactor with cell recycle was employed. A cell density of 145 g dry weight/ℓ and a volumetric productivity of 73 g/ℓ·h were obtained with an effluent concentration of 85 g/ℓ lactic acid. The productivity achieved by this system was 23-fold higher than those obtained by the corresponding batch cultivations. Once the lactic acid concentration reached the steady state, lowering the yeast extract concentration caused the reduction of the lactic acid concentration without affecting the biomass concentration. Finally, the formation of D-lactate was investgated. During the various cultures, a small amount of D-lactate always formed, even though a majority of lactate was L-isomer. It was supposed that the relative amount of the D-lactate was affected by glucose limitation, and there seems to exist a certain relationship between the concentration of D-lactate and acetate.
장현용,Yoo-Sung Jung,김종택,Chun-Keun Park,정희태,Choung-Ik Kim,양부근 사단법인 한국동물생명공학회 2006 Reproductive & developmental biology Vol.30 No.1
Hypoosmotic swelling test (HOST) is used for evaluating the plasma membrane function and fertilizing ability in mammal spermatozoa. However, HOS solutions and experimental conditions have not been determined clearly for assessing canine spermatozoa. This study was conducted to examine the HOS solutions and assay conditions, including incubation time (30 to 120 min), storage temperature (4, 17 and 20℃), semen status (fresh and frozen). Maximum spermatozoal plasma membrane swelling was obtained in an 150 mOsm Na-citrate/Fructose solutions with an incubation time for 45 min. The storage temperature and semen status affected the percentage of HOS positive spermatozoa. The HOS test adapted to canine spermatozoa in this study was simple and highly consistent assay with good repeatability. The optimal condition of HOST in canine spermatozoa is an 150 mOsm Na-citrate/Fructose solutions with an incubation time for 45 min regardless of semen storage temperature and semen status.