• 한국식품조리과학회지
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• 제24권6호
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• pp.735-741
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• 2008

The principal objective of this study was to evaluate the quality characteristics of yogurt to which had been added extracts of low quality dried persimmons, in an attempt to expand the range of use of low-quality dried persimmons. In the results of our sensory evaluation, our optimal results were attained with the addition of 5 g of dried persimmon extracts, 90 g of water, 20 g of oligosaccharide, and 50 g of fructose at a specific level of 1000 mL. During the 20-day storage period, the pH value of the dried persimmon yogurt was lowest on the 15th day in the control group and the 20th day in the yogurt to which 0.5% extract had been added. The titratable acidity was lowest by a significant margin on the 10th day for all types of yogurt. Viscosity assays showed a stable level of acidity over different storage periods. The number of viable cells demonstrated a trend toward increase with passing time, and the number of viable cells in the dried-persimmon yogurt was higher than that in the control yogurt.

• 한국식품과학회지
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• 제30권4호
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• pp.902-907
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• 1998

본 연구에서는 세포 고정화를 위해 기존의 고정화 방법의 단점을 보완하기 위하여 새롭게 개발된 GFM 시스템에 Paracoccus denitrificans를 고정화하여 물속의 nitrate를 분해하는데 적용하였다. 고정화 조건으로써 스폰지 구멍의 크기 20 P.P.I. (pore per inch)와 겔로서 alginate가 이미 최적의 조건으로서 선택되었다. 고정화 세포의 연속 nitrate 분해능력을 air-lift reactor내에서 측정한 결과, 물속의 nitrate함량이 증가함에 따라 분해능력이 증가함을 나타내었다. 또한 연속운전에서 본 시스템은 기존의 고정화시스템인 bead 겔포괄법과 비교할 때 $1.2{\sim}2.1$배 정도 분해능력이 향상되었다. 최고 nitrate 분해속도는 buffer를 함유한 medium에 있어서 177 mg/L h이었으나 buffer를 첨가하지 않은 경우에 있어서는 33 mg/L h이었다. 또한 저장안정성을 측정한 결과, $5^{\circ}C$에 저장하였을 때 분해능력은 16주간 거의 변화가 없었으며 고정화하지 않은 자유세포나 bead에 고정화된 세포에 비하여 저장안정성이 두드러지게 뛰어났음을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제6권1호
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• pp.36-42
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• 1996

The production of sorbitol by permeabilized cells of Zymomonas mobilis immobilized in $\kappa$-carrageenan was investigated. Cetyltrimethylammoniumbromide (CTAB) permeabilized cells were treated with glutaraldehyde prior to immobilization for cross-linking of enzymes, glucose-fructose oxidoreductase (GFOR) in cells. Rigidity of the immobilized beads was increased two-fold with 90$\%$ conversion efficiency by the additions of 40$\%$ (w/v) polyols (glycerol 25 g + propylene glycol 15 g) to 60$\%$ (w/v) distilled water containing 2.5$\%$ (w/v) $\kappa$-carrageenan as a final concentration, prior to immobilization. $\kappa$-Carrageenan beads entrapping permeabilized cells were dried to improve bead rigidity and storage stability. During s6mi-batch process for 72 h with dry beads, there was an improvement of the loss of enzyme activity (less than 10$\%$). In batch process, the kinetic results of $K_m.fructose$ value for the free cells, wet beads and dry $\kappa$-carrageenan beads were 71.7, 72.4 and 116.7 g/l, respectively. Higher productivity was obtained with two-stage continuous packed bed reactors with both wet and dry $\kappa$-carrageenan beads at 25.00 and 21.15 g/l/h, respectively, when measured at second stage.

• 한국환경과학회지
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• 제19권11호
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• pp.1445-1456
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• 2010

This study presented seasonal changes of the phytoplankton community in Junam reservoir by pollution and water quality of the lake. The water storage of the reservoir is 5.3 million ton, most of which are being utilized for agricultural, industrial and residential purposes. The annual precipitation during the investigation period was 1,868.9 mm, increasing by 20% from the average annual level of 1,506.7 mm in 2009. The annual average water storage was 57.3%. It decreased during agricultural season and then increased again after monsoon rainfall. The loads of BOD were $3,799kgday^{-1}$, and 81% of them came from livestock and household. The TN and TP loads were $1,164kgday^{-1}$ and $170kgday^{-1}$, respectively, and 76% of them came from livestock. We assessed water quality of the Junam reservoir using 17 variables. According to the result, the reservoir met the fourth grade, meaning slightly bad, because of high concentration of COD, SS and chlorophyll-a. Eutrophication assessment was conducted by revised Carlson's Index (TSIm, Aizaki), and it was found that the entire lake was eutrophicated with high chlorophyll-a concentration all through the year, except during February to April and in July. A total of 76 phytoplankton species were identified from the samples. Among them, the largest number of species were Chlorophyceae with 33 species(43.4%), followed by Bacilliophyceae with 27 species(35.5%), Cyanophyceae with 8 species(10.5%), and Cryptophyceae with species(10.5%). The total cell number of phytoplankton was the highest in October(7,884 cells $mL^{-1}$) among Cyanophyceae and Bacilliophyceae. The seasonal succession of Chlorophyceae (Chlamydomonas spp.), Cyanophyceae(Microcystis aeruginosa) and Cryptophyceae(Rhodomonas spp.) was observed during January to May, July to September and October to December respectively.

• Applied Microscopy
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• 제19권1호
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• pp.49-58
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• 1989

Ultrastructure of the excretory duct of the small ampullate gland in the orb web spider, Nephila clavata L. Koch are studied with light and electron microscopes. The small ampullate glands, located near the midline portion of the abdominal cavity, are connected with the spigots(large spinning tubes) on the middle spinnerets and composed of three parts which are the excretory duct, the storage sac and the convoluted tail. The excretory duct of this gland is enclosed by a thin layer of the outer connective tissues. By the morphology of the apical cuticles and internal textures of the epithelial cells, the duct is subdivided into two regions which are proximal duct region near the sac and distal duct region near the spinnerets. At the distal region of the ducts, the subcuticle which had the function of water removal form the progenetive silk material is well developed, whereas at the proximal region this cuticle disappeared and instead of these, endocuticle is developed. Moreover the epithelium of the distal duct region is composed of columnar epithelial cells, but at the proximal region the epithelium is changed to squamous or cuboidal forms. In the cytoplasm of the epithelial cells, rough endoplasmic reticula, Golgi comlexes and large secretory vesicles related to the production of the cuticular materials are well developed. And between the adjacent epithelial cells, specialized septate junction and desmosomes are formed along the plasma membrane.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.262-267
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• 2004

This study was done to observe the occurrence of heterotrophic bacteria in terms of free chlorine residuals in two different water distribution systems, which belongs to both K and Y water treatment plant of S city in Korea. The data analyzed in the distribution systems show that the free chlorine residuals decreased from 0.10 to 0.56 mg/l for K, and 0.51 to 0.78 mg/l for Y. The decay of free chlorine is clearly higher in both March and August than in January. The HPC in the distribution systems are ranged from 0 to 40 cfu/ml for K, 0 to 270 cfu/ml for Y, on $R_2$A medium. In particular, its level is relatively high at the consumer's ground storage tanks, taps, and the point-of-end area of Y. The predominant genera that were studied in the distribution systems were Acinetobacter, Sphingomonas (branch of Pseudomonas), Micrococcus, Bacillus, Staphylococcus. The diversity of heterotrophic bacteria increases in the end-point area. Most of them are either encapsulated cells or of Gram-positve cocci. In conclusion, the point-of-end area in distribution systems shows the longer flow distance from the water treatment plants, along with a greater diversity and a higher level of heterotrophic bacteria, due to the significant decay of free chlorine residuals.

• Biomaterials and Biomechanics in Bioengineering
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• 제1권3호
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• pp.163-174
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• 2014

The objective of this study is to prepare an artificial extracellular matrix (ECM) for cell culture by using polymer hydrogels. The polymer used is a cytocompatible water-soluble phospholipid polymer: poly[2-methacryloyloxyethyl phosphorylcholine (MPC)-n-butyl methacrylate-p-nitrophenyloxycarbonyl poly(ethylene oxide) methacrylate (MEONP)] (PMBN). The hydrogels are prepared using a cross-linking reaction between PMBN and diamine compounds, which can easily react to the MEONP moiety under mild conditions. The most favorable diamine is the bis(3-aminopropyl) poly(ethylene oxide) (APEO). The effects of cross-linking density and the chemical structure of cross-linking molecules on the mechanical properties of the hydrogel are evaluated. The storage modulus of the hydrogel is tailored by tuning the PMBN concentration and the MEONP/amino group ratio. The porous structure of the hydrogel networks depends not only on these parameters but also on the reaction temperature. We prepare a hydrogel with $40-50{\mu}m$ diameter pores and more than 90 wt% swelling. The permeation of proteins through the hydrogel increases dramatically with an increase in pore size. To induce cell adhesion, the cell-attaching oligopeptide, RGDS, is immobilized onto the hydrogel using MEONP residue. Bovine pulmonary artery endothelial cells (BPAECs) are cultured on the hydrogel matrix and are able to migrate into the artificial matrix. Hence, the RGDS-modified PMBN hydrogel matrix with cross-linked APEO functions as an artificial ECM for growing cells for applications in tissue engineering.

• 에너지공학
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• 제25권2호
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• pp.65-78
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• 2016

광촉매 연구의 초기는 태양에너지의 전환 및 저장에 관련된 분야들로부터 개발되어 왔다. 최근에는 광 또는 광촉매의 존재 하에서 자외선을 조사하여 물의 정제 및 폐수처리와 각종 유기화합물의 분해연구가 활발하게 진행되고 있다. 또한 산화물질-카본나노튜브, 그래핀 나노복합체 등이 광촉매물질로서 연구되고 있다. 이와 같은 복합체는 열적, 화학적으로 안정하기 때문에 플렉서블 소자를 포함한 광분해 태양전지 및 나노전자 소자를 구성하는 재료로서 적당하다.

• 한국식품저장유통학회지
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• 제17권4호
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• pp.457-465
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• 2010

다양한 건강 기능성을 가진 오미자 추출물을 첨가하여 맛과 색상이 우수한 정과를 개발할 목적으로 연근 정과를 제조한 후 $25^{\circ}C$에 12주간 저장하면서 종합적인 품질특성 변화를 조사하였다. 연근 정과의 pH와 산도는 오미자 첨가량이 많을수록 pH가 낮고 산도가 높았다. 저장초기의 수분함량은 약 8%였으며, 저장 2주까지 수분함량이 14-17%까지 증가한 후, 저장말기까지 큰 변화가 없었으며 대조군은 오미자 첨가구보다 수분함량이 낮았다. 연근 정과의 총균수는 저장 초기에 2.4~3.2 log CFU/g이었으며 저장 말기까지 4 log CFU/g에 미달되었으며 오미자의 첨가량이 증가할수록 총균수와 효모 곰팡이수는 낮은 균수를 유지하여 저장성이 향상되었다. 연근 정과의 저장중 색상은 오미자 첨가량이 많을수록 명도(L), 적색도(a), 황색도(b) 모두 대조군이 가장 높았으며 오미자 첨가량이 많을수록 유의적으로 낮은 색도를 유지하였다(p<0.001). 연근 정과의 저장중 물성은 저장초기에 오미자 첨가농도에 따른 차이가 컸으나 저장기간이 길어질수록 각 시료간의 물성 차이가 감소하였으며, 오미자 첨가량이 많을수록 견고성(hardness)과 강도(strength)가 유의적으로 낮았다(p<0.05). 연근 정과의 저장중 기호도는 색상(color), 단맛(sweet taste), 신맛(sour taste), 씹힘성(chewiness), 뒷맛(after taste)과 종합적인 기호도(overall preference)에서 2~4% 첨가군에서 유의적으로 높은 기호성을 나타내어, 연근 정과 제조시에 오미자의 최적 첨가농도는 2~4%가 적절한 것으로 판단되었다.

• 생명과학회지
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• 제11권5호
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• pp.489-495
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• 2001

대두 발아종 오존수 처리에 의한 배유세포와 산성 인산호효소의 변화에 관해서 전자현미경으로 조사한 결과는 다음과 같다. 산성 인산화효소의 활성은 발달하고 있는 종자 배유의 여러 소기관에 나타났는데, 효소의 활성은 0.5 ppm 오존수를 처리한 후 12시간 배양중에 나타났다. 오존수를 처리한 후 배유가 분화함에 따라 산성 인산화효소의 반응산물은 액포내에 축적되는 것으로 나타나는데, 이것은 산성 인산화효소가 세포간 저장물질의 분해와 이동에 관여하는 것으로 여겨진다.