• 대한의용생체공학회:의공학회지
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• 제7권1호
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• pp.75-79
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• 1986

In this paper, a multigate pulsed doppler system with parallel signal processing which enables the transcutaneous assesment of the blood-flow velocities of five adjacent sample volumes is developed. The outputs of the system are audio signals, velocity curves and velocity profiles of 5 adjacent sample volumes. We have applied to the major superficial arteries and obtained the detailed information about the time dependent blood-flow behavior.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.746-749
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• 2003

Alignment of 2D-gel images of biological samples can visualize the difference of expression profiles and also inform us candidates of protein spots to be further analyzed. However, comparison of two proteome images between case and control does not always successfully identify differentially expressed proteins due to sample-to-sample variation. Because of poor reproducibility of 2D-gel electrophoresis, sample-by-sample variations and inconsistent electrophoresis conditions, multiple number of 2D-gel image must be processed to align each other to visualize the difference of expression profiles and to deduce the protein spots differentially expressed with reliability. Alignment of multiple 2D-Gel images and their clustering were carried out by applying various algorithms and statistical methods. In order to align multiple images, multiresolution-multilevel algorithm was found out to be suitable for fast alignment and for distorted images. Clustering of 12 different images implementing a k-means algorithm gives a phylogenetic tree of distance map of the proteomes. Microsoft Visual C++ was used to implement the algorithms in this work.

• Archives of Pharmacal Research
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• 제17권5호
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• pp.360-363
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• 1994

Column--swtiching technique with a reversed-phase high performance liquid chromatographic method has been developed for the routine analysis of radioiodinated insulin and its degadation products in biological fluids. The diluted biological samples were loaded onto a precolumn packed with LiChrosorb RP-8 $(25-40{\;}{\mu}m)$ using 0.1% trifuoroacetic acid (TFA) in water as a washing solvent. After valve switching, the concentrated insulins were eluted in the back-flush mode and separated by a W-Porex $C_{18}$ column with a gradient of 0.1% TFA in water and 0.1% TFA in acetonitrile as the mobile phase. The method showed good precision, accuracy and speed with the detection limit of 20 pg/ml. Total analysis time per sample was about 40 min and the coefficients of variation were less than 8, 2%.

• 생태와환경
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• 제43권4호
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• pp.477-491
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• 2010

Benthic macroinvertebrates were collected two times from 116 sites at the $1^{st}{\sim}4^{th}$ order streams in forest areas in Gyungsang province in late spring and late summer. The sample sites belonged to slightly and moderately polluted states. When communities were classified by the Self-Organizing Map (SOM), the gradient was observed according to degree of pollution. Within clusters of slightly polluted sites, however, seasonality was further observed. Scrapers, gatherer-collectors, and filterer-collectors were abundantly observed in late spring while shredders appeared more in late summer. The number of predator species increased in late summer. Behavior types were mostly clingers in two seasons. Community compositions at the moderately polluted sites were not much differentiated in different seasons. Gatherer-collectors and burrowers were dominantly collected in both seasons.

• Applied Microscopy
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• 제42권1호
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• pp.49-52
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• 2012

For TEM study of biological samples or polymers that are contained in organic structure, it is often required that the sample is prepared by using ultramicrotome and stained with proper agents to increase the contrast of organic structure. In this study, we investigated an efficient TEM sample preparation method for ductile heterogeneity material by using ultramicrotomy. Cryo-ultramicrotomy is a suitable method that is capable of rendering sample hardness for various ductile materials. However, it has several factors to consider, such as experimental cost, working time and finding the optimal staining conditions. To satisfy these considerations, we prepared TEM sample by using ultramicrotome without cryofunction, and secured the sample hardness by applying the staining process prior to ultrathin sectioning. The cross-linked polyethylene structure in the sample was stained with the 2% $RuO_4$ solution in a sealed test tube for 24 hours at $4^{\circ}C$. After the sample staining, ultrathin sections of sample were prepared using ultramicrotome. As a result, it was revealed that the difficulties associated with staining of ultrathin sections prepared by low-temperature conditions were improved. In addition, appropriate staining depth of sample could be selected for sectioning process. The quality of TEM sample obtained by using this method was better than that of cryo-ultramicroscopy. Finally, it is expected that our method could be effectively applied in TEM sample preparation for a variety of nano-bio convergence materials.

• 생태와환경
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• 제35권4호통권100호
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• pp.295-305
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• 2002

1996년 4월부터 1998년 3월까지 서울의 한강지류 3차 하천인 양재천 200m구간에서 저서성 대형 무척추동물을 채집하였다. 유기물 오염으로 인해 종풍부도가 상대적으로 낮았지만 군집 풍부도양상은 조사지점에 따라 다르게 나타났다. 유속이 높고 큰 하상구성물이 많은 직류부 조사지점에서는 종풍부도가 높았고 유기물오염에 상대적으로 내성이 낮은 종들이 추가적으로 출현하였다. 반대로 유속이 느리고 퇴적이 많이 이루어진 소(pool)에 위치한 조사지점에서는, 종풍부도는 낮았고, 유기오염물에 내성이 강한 수종이 많이 채집되었다. 중요요인분석에서 직류부의 조사지점은 유속, 마찰유속(shear velocity)과 관련성이 있었고, 유기물오염에 내성이 비교적 낮은 다양한 종들과 연관성을 나타냈다. 특히 큰 하상구성물을 심은 지점은 하상구성물의 다양도나 조도(roughness)와같은 수리학적 (hydraulics)특징과 관련되었고, 하천의 부분적 회복을 나타내는 종들과 관계가 있었다. 소에 위치하는 조사지점은 하상구성물에 퇴적한 유기물과 유기물오염에 내성이 강한 빈모류나 깔따구류와 연관을 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1071-1077
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• 2019

Natural gamma-decalactone (GDL) produced by biotransformation is an essential food additive with a peach-like aroma. However, the difficulty of effectively controlling the concentration of the substrate ricinoleic acid (RA) in water limits the biotransformation productivity, which is a bottleneck for industrialization. In this study, expanded vermiculite (E-V) was utilized as a carrier of RA to increase its distribution in the medium. E-V and three commonly used organic compounds were compared with respect to their effects on the biotransformation process, and the mechanism was revealed. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis indicated that RA was physically adsorbed onto the surface of and inside E-V instead of undergoing a chemical reaction, which increased the opportunity for interactions between microorganisms and the substrate. The highest concentration of GDL obtained in the medium with E-V was 6.2 g/l, which was 50% higher than that in the reference sample. In addition, the presence of E-V had no negative effect on the viability of the microorganisms. This study provides a new method for producing natural GDL through biotransformation on an industrial scale.

• 한국식품영양과학회지
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• 제33권1호
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• pp.28-33
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• 2004

여러 가지 생약재와 녹용이 첨가되어 보혈 강장제, 활력강화 및 성장촉진 효과가 있는 전통 한약탕제인 녹용대보탕에 대하여 in vitro에 의한 전자 공여작용과 지질과산화 억제효과 등의 항산화 활성과 아질산염 소거효과, tyrosinase 억제효과 그리고 혈소판 응집 억제활성 등을 분석하였다. 본 실험에서 사용한 한약탕제의 총 페놀함량은 151.3$\pm$2.6 mg%로 확인되었으며, 80.9%의 전자 공여효과를 나타냈다. 리놀레산을 이용한 지질과산화 억제효과는 88.1%로 나타났으며, pH에 따른 아질산염 소거효과를 비교 검토한 결과 시료의 아질산염 소거 효과는 산성 pH에서 70%정도의 활성을 나타냈으며 pH 1.2에서 가장 높고, pH 6.0에서 가장 낮은 소거효과를 나타내 pH가 높아질수록 그 활성이 낮았다. Tyrosinase 억제효과는 80%이상으로 나타났으며, SD rat의 혈소판을 ADP로 자극하였을 때 일어나는 혈소판 응집 에 대한 저해활성을 측정한 결과 약30%의 혈소판 응집 억제효과를 보였다. 또한 이들 억제효과는 농도 의존적으로 일어남을 알 수 있었다.

• 환경생물
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• 제26권3호
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• pp.183-191
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• 2008

The effect of silver ion solution on the growth of Microcystis aeruginosa UTEX 2388 (cyanobacterium) and Chlorella sp. KCTC AG20136 (green alga) was investigated using separated and mixed culture in filtered natural water and BG11 medium. In separated culture, M. aeruginosa UTEX 2388 and Chlorella sp. KCTC AG20136 were found to be sensitive to 0.01 and 0.1 mg L$^{-1}$ of silver ion, respectively. Also, the silver ion concentrations for the growth inhibition of M. aeruginosa UTEX 2388 and Chlorella sp. KCTC AG20136 in the mixed culture were same in separated culture. Cyanobacteria were more sensitive to the silver ion solution than green algae. In bloom sample, the minimal inhibition concentration of silver ion solution for the low Chl-${\alpha}$ sample (110$\sim$190 ${\mu}g$ L$^{-1}$) and high Chl-${\alpha}$ sample (1,500$\sim$1,900 ${\mu}g$ L$^{-1}$) was about 0.1 and 3.0 mg L$^{-1}$, respectively. The silver ion concentration for the inhibition of algal bloom sample was affected by the algal biomass. In order to use silver ion solution for the control of algal bloom, the silver ion concentration must be determined in consideration of a minimal effect on the environment.

• Applied Biological Chemistry
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• 제35권4호
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• pp.265-271
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• 1992

키틴과 키토산으로부터 carboxymethylchitin, acetylchitin, ethylchitosan, N-acetylchitosan 및 chitosansulfate를 합성하여 그 물리화학적 기능특성을 키틴 및 키토산과 비교 검토 하였다. Carboxymethylchitin은 물과 아세트산에 용해되었지만 ethylchitin은 아세트산에만 용해되었다. 보수력은 N-acetylchitosan이 1194%로 키틴에 비해 약 2배 정도 높았으며, 지방흡수력은 carboxymethylchitin이 1800%로 키틴 511%에 비해 월등히 높았다. Carboxymethylchitin의 유화성이 75.91%로 가장 높았으며 그 다음이 미세결정형 키틴으로 57.02%였으나 키틴 및 키토산은 유화성이 나타나지 않았다. 색소흡착능은 acetylchitin이 0.93 mg dye/g sample(Blue R-250), 0.96 mg dye/g sample(Red-2)로 키틴 및 키토산 보다 높았다. 따라서 carboxymethylchitin은 유화제로서, acetylchitosan은 색소흡착제로서 이용이 가능할 것으로 판단된다.