• 상하수도학회지
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• 제29권1호
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• pp.77-88
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• 2015

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.

• 한국응용과학기술학회지
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• 제30권4호
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• pp.635-648
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• 2013

This study was carried out to investigate the emulsifying properties of surface-active substances from defatted rapeseed cake by supercritical $CO_2$ extraction. Based on the interfacial tension data, a supercritical fluid extract (SFE) with the lowest value of 14.16 mN/m was chosen for evaluation which was obtained from No. 2 extraction condition (150 bar, $65^{\circ}C$, 250 g). For emulsions with SFE, some physicochemical properties (i.e., fat globule size, creaming stability, zeta potential etc) were investigated according to changes in SFE concentration, pH, and NaCl addition in an emulsion. It was found that fat globule size was decreased with increasing SFE concentration in emulsion, with showing a critical value at 0.5 wt%, thereby resulting in less susceptibility to creaming behavior. The SFE emulsion also showed instability at acidic conditions (pH<7.0) as well as by NaCl addition. This was coincided with zeta potential data of emulsion. In addition, SSL (sodium stearoyl lactylate) found to be suitable as a co-surfactant, as it helped considerably in decreasing fat globule size in emulsions and its optimum concentration to be over 0.03 wt%, based on 0.1 wt% SFE in emulsion.

• 공업화학
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• 제35권2호
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• pp.67-78
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• 2024

흡광은 측정이 간편하고 해석의 직관성이 높다는 점에서 생화학 기반 분석법의 신호로서 강점을 가진다. 흡광을 가지는 물질 중에서 금 나노입자는 화학적 안정성, 생물학적 친화성, 가시광선 범위에서 야기되는 국소 표면 플라즈몬 공명(localized surface plasmon resonance, LSPR)에 의한 독특한 광학적 특성 등의 유용한 성질을 지니며, 특정 표적 물질에만 유효한 다른 발색물질과 비교해 항체나 압타머 등 다양한 검출 활성물질과 접합이 용이하여 확장성을 가진다. 특히, 기질의 산화로 발색을 야기하는 효소 기반 발색법에 비해 낮은 가격, 쉬운 입자 합성, 높은 환경안정성 등의 장점으로 인해 비색화 분석법의 신호물질로서 광범위하게 연구되고 있다. 본 총설에서는 이와 같은 금 나노입자를 신호물질로 활용하는 다양한 전략을 최근의 연구들을 중심으로 요약 정리하였으며, 입자의 형태에 광학 특성이 영향을 받는 금 나노입자의 특징에 착안하여 신호생성 시에 활용한 금 나노입자의 형태 제어 전략을 기준으로 문헌들을 분류하고 검토하였다. 이를 통해 이미 오랜 기간 활용되어온 금 나노입자가 현재에도 흡광 신호물질로서 여전히 활발하게 연구되고 있다는 사실을 고찰하고, 향후에도 광범위하고 지속적으로 개선될 여지를 가진다는 점을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1635-1643
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• 2009

The aim of this study was to provide new insight into the mechanism whereby the housekeeping enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) locates to cell walls of Lactobacillus plantarum 299v. After purification, cytosolic and cell wall GAPDH (cw-GAPDH) forms were characterized and shown to be identical homotetrameric active enzymes. GAPDH concentration on cell walls was growth-time dependent. Free GAPDH was not observed on the culture supernatant at any time during growth, and provoked cell lysis was not concomitant with any reassociation of GAPDH onto the cell surface. Hence, with the possibility of cw-GAPDH resulting from autolysis being unlikely, entrapment of intracellular GAPDH on the cell wall after a passive efflux through altered plasma membrane was investigated. Flow cytometry was used to assess L. plantarum 299v membrane permeabilization after labeling with propidium iodide (PI). By combining PI uptake and cw-GAPDH activity measurements, we demonstrate here that the increase in cw-GAPDH concentration from the early exponential phase to the late stationary phase is closely related to an increase in plasma membrane permeability during growth. Moreover, we observed that increases in both plasma membrane permeability and cw-GAPDH activity were delayed when glucose was added during L. plantarum 299v growth. Using a double labeling of L. plantarum 299v cells with anti-GAPDH antibodies and propidium iodide, we established unambiguously that cells with impaired membrane manifest five times more cw-GAPDH than unaltered cells. Our results show that plasma membrane permeability appears to be closely related to the efflux of GAPDH on the bacterial cell surface, offering new insight into the understanding of the cell wall location of this enzyme.

• 한국정밀공학회지
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• 제2권2호
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• pp.69-75
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• 1985

The object of this study is to discuss the effect of cutting fluid on the mechanism of chip formation in orthogonal cutting. Rehbinder effect has been known as a phenomenon, the reduction of mechanical strength, when the metal is exposed in a polar organic environment or the surface of metal is coated with some polar organic substances. About the cause of Rehbinder effect there have been many different ideas by Rehbinder, Merchant, Shaw, Sakakida and etc. In this report, the effects of surface active medium (magic ink) upon the mechanism of chip formation on the orthogonal cutting of copper and the mechanical properties of the work material are experimentally discussed with constant rake angle. Under the condition of polar organic environment the experimental results are as follows; 1) The chip thickness becomes thinner and slip line pitch on the free surface of chip becomes smaller than that of dried cutting area. 2) The order of alternation of cutting ratio was changed. 3) The friction angle on the tool face is not affected by the depth of cut. 4) The cutting force and shear strain on the shear plane decrease remarkably, therefore the work material must be embrittled under polar organic environment.

• 한국수산과학회지
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• 제30권3호
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• pp.451-458
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• 1997

The oxygen transfer coefficient was not significantly affected by either flow pattern, initial bubble size or the wastes present in the water studied. Surface active substances in the water did however influence the transition from bubble to slug flow. Airlift with length to diameter ratios less than 50 suffered from considerable losses in efficiency. When properly designed, airlift pumping efficiencies were comparable to those of conventional centrifugal pumps and the oxygen transfer efficiency were as high as or higher than those of diffused aeration systems.

• Anatomy and Cell Biology
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• 제56권2호
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• pp.166-178
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• 2023

Undeniably, endothelial cells (EC) contribute to the maintenance of the homeostasis of the organism through modulating cellular physiology, including signaling pathways, through the release of highly active molecules as well as the response to a myriad of extrinsic and intrinsic signaling factors. Review the data from the current literature on the EC role in norm and disease. Endothelium maintains a precise balance between the released molecules, where EC dysfunction arises when the endothelium actions shift toward vasoconstriction, the proinflammatory, prothrombic properties after the alteration of nitric oxide (NO) production and oxidative stress. The functions of the EC are regulated by the negative/positive feedback from the organism, through EC surface receptors, and the crosstalk between NO, adrenergic receptors, and oxidative stress. More than a hundred substances can interact with EC. The EC dysfunction is a hallmark in the emergence and progression of vascular-related pathologies. The paper concisely reviews recent advances in EC (patho) physiology. Grasping EC physiology is crucial to gauge their potential clinical utility and optimize the current therapies as well as to establish novel nanotherapeutic molecular targets include; endothelial receptors, cell adhesion molecules, integrins, signaling pathways, enzymes; peptidases.

• 한국미생물·생명공학회지
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• 제7권3호
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• pp.165-173
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• 1979

자연선조사한 대장균B주의 세포분열회복활성분을 구명코저 자외선내성균인 대장균 B/r 주의 초음파추출액으로부터 활성성분分을 분리한 결과 $\beta$-NAD가 관여함이 발표되었다. 본고에서는$\beta$-NAD 이외 Magnesium이 활성물질의 안정화가 중요한 역할을 나타냄을 구명하였으며 10~30%의 서당밀 도구배원심분리에 의해 2 개의 새로운 활성부분이 있음을 확인하였다. 2 개의 활성물질 가운데 하나는 원심관의 최하부에 위치하였으며 또 다른 하나는 상부의 분자량 45,000 부위에서 회수되었다. 하부에 위치한 활성획분은 Mg++이 그 활성에 무관하였으나 상부의 저분자 활성부분은 $Mg^{++}$을 첨가하지 않으면 회수가 불가능하였다. 저분자활성부분은 pronase에 대해 감수성이었으며 DNA-ligase 는 아님이 추정되었다. 초원심분리과정에 $N_2$ gas를 처리할 경우 aeration에 비해 약 2 배의 활성이 나타났다. $Mg^{++}$은 $\beta$-NAD에 또하나의 회복활성 및 필수적인자로 요구된다고 생각된다.

• The Plant Pathology Journal
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• 제20권4호
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• pp.293-296
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• 2004

During the screening of antiviral substances having inhibitory effects on Tobacco mosaic virus (TMV) infection on tobacco plants, we found a bacterial isolate KTB3, and identified it as Acinetobacter sp. which strongly inhibited the infection of TMV When the culture filtrate from KTB3 was applied on the upper surface of the Xanthi-nc tobacco leaves at the same time, or 24 hours before TMV inoculation, almost complete inhibition was achieved. Likewise, 86% inhibition was achieved, when the culture filtrate was applied on the underside of the leaves. In field trials, transmission of TMV from diseased seedlings to healthy ones during transplanting work was reduced by 92%, when the culture filtrate was sprayed onto the tobacco seedlings, cv. NC82, 24 hours before transplanting. No toxic effect was observed on the tobacco plants. Antiviral substance from the culture filtrate was purified by ethanol precipitation, dialysis, DEAE-cellulose, and Sephadex G75 gel column chromatography. The partially purified active material which showed positive color reaction to sugar and protein inhibited TMV infection by 60% at 1 ${\mu}$g/ml.

• 환경생물
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• 제22권1호
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• pp.184-191
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• 2004

To investigate bacteria with algalytic activities against Anabaena cylindrica when water blooming occurs and to study enzyme profiles associated with alga-lytic activity, various bacterial strains were isolated from surface waters and sediments in eutrophic lakes or reservoirs in Korea. Among 178 isolates, only nine isolates exhibited lytic abilities against A cylindrica on the agar plates, and then the isolate AK-13 was selected as the strongest in lysing the cyanobacterium A. cytindrica. The strain AK-13 was characterized and identified as Sinorhizobium sp. based on fatty acid methyl ether profiles and 16S rDNA sequence. According to the results of the enzyme assays, in the strain An-13 of Sinorhizobium sp., alginase, amylase, proteinase (caseinase and gelatinase), carboxymethyl-cellulase (CMCase), laminarinase, and lipase was produced, namely CMCase, laminarinase and protease were highly active. None of glycosidase was produced. Therefore, enzyme systems of Sinorhizobium sp. AK-13 were very complex to degrade cell walls of A. cylindrica. The peptidoglycans of A. cylindrica mat be hydrolyzed and metabolized to a range of easily utilizable monosaccharides or other low molecular weight organic substances by Sinorhizobium sp. AK-13.