• 한국광학회지
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• 제10권1호
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• pp.1-4
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• 1999

공초점 현미경 시스템을 사용하여 반복률이 17MHz이며, 중심파장이 638nm인 극초단 펄스 다이오드 레이저에 의해서 여기된 단분자의 형광폭발신호를 게측하였다. 에칠렌글리콜 용액에 있는 적색 색소 분자(JA22)를 시료로 사용하였다. 시상관 단광자 계수기응 사용하여 단분자들의 현광소멸곡선을 수집하였으며, maximum likelihood estimator로 그것들을 분석하였다. 색소 분자당 40개 이상의 광자수를 가지고 분석하였을 때, 21%의 오차 확률로 형광소멸시간을 계측하는 것이 가능하였다.

• 한국광학회지
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• 제8권4호
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• pp.353-355
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• 1997

공초점 형광 현미경과 단일 광자 계수기로 구성되어 있는 단일 분자 검출장치를 사용하여, 색소 농도에 따른 광자 계수율의 변화를 관측하였다. 농도가 증가함에 따라 계수율이 포화하는 경향을 보였으며, 광검출기의 죽은 시간을 고려하여 측정 결과를 설명하였다. 계수율과 검출 부피, 광검출기의 양자효율, 입사 광량 사이의 관계를 나타내는 관계식을 제시하였다. 또한 신호대 잡음비에 대해서도 간략하게 논하였다.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.305-309
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• 2010

Photopolymer films containing fluorescent anthracene polymer, polymethyleneanthracene (PMAn), were prepared with different concentrations of PMAn for holographic recording useful for security documents. The fluorescent photopolymer film showed enhanced fluorescent intensity due to the micro-separation which arose from grating formation and diffusion during photopolymerization. Experimental values of diffraction efficiency were well matched to the simulated values for photopolymers having different PMAn concentrations. Holography patterning was carried out using the fluorescent photopolymer under a photo-mask. A grating was confirmed using microscope techniques in the recorded area under the pattern. Importantly the recorded area showed enhanced fluorescence compared to the unrecorded part, allowing fluorescence patterns at micro scale along with the submicron grating pattern. The fluorescence pattern recorded on the photopolymer film provides additional readability of holographic reading and thus is useful for secure recording and reading of information.

• Applied Microscopy
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• 제51권
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• pp.12.1-12.12
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• 2021

Intravital video microscopy permits the observation of microcirculatory blood flow. This often requires fluorescent probes to visualize structures and dynamic processes that cannot be observed with conventional bright-field microscopy. Conventional light microscopes do not allow for simultaneous bright-field and fluorescent imaging. Moreover, in conventional microscopes, only one type of fluorescent label can be observed. This study introduces multispectral intravital video microscopy, which combines bright-field and fluorescence microscopy in a standard light microscope. The technique enables simultaneous real-time observation of fluorescently-labeled structures in relation to their direct physical surroundings. The advancement provides context for the orientation, movement, and function of labeled structures in the microcirculation.

• 대한약침학회지
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• 제7권3호
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• pp.73-76
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• 2004

We report the new threadlike structures outside the blood vessels of mice. For this, we developed an in-situ searching method of the structure by vital staining with the dye of acridine orange and using a fluorescent stereomicroscope designed specifically for this purpose. We consider that the newly found threadlike structure might be rediscovery of the extra-vascular Bonghan duct which was reported in 1963 by Bonghan Kim.

• Molecules and Cells
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• 제23권2호
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• pp.170-174
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• 2007

High-throughput subcellular imaging is a powerful tool for investigating the function of genes. In order to identify novel regulators of apoptosis we transiently transfected HeLa cells with 938 hypothetical genes of unknown function, and captured their nuclear images with an automated fluorescence microscope. We selected genes that induced greater than 3-fold increase in the percentage of apoptotic nuclei compared with vector-transfected cells. The full-length genes C10orf61, MGC 26717, and FLJ13855 were identified as candidate proapoptotic genes, and their apoptotic effects were confirmed by DNA fragmentation ELISAs and Western blotting for caspase-7 and PARP. We conclude that a subcellular image-based apoptotic screen is useful for identifying genes with proapoptotic activity.

• Genomics & Informatics
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• 제4권2호
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• pp.77-79
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• 2006

In order to identify novel proapoptotic genes, we screened approximately 1,000 hypothetical genes whose functions are completely unknown. After these genes were transiently expressed in HeLa cells, their nuclei images were captured using automated high-speed fluorescence microscope, through which the ratio of apoptotic nuclei was estimated. We selected genes that induce greater than 3-fold increase in apoptotic nuclei compared to that of the vector control. The candidate proapoptotic genes were sequenced and their effects on cell death were further confirmed by the additional assay, DNA fragmentation ELISA. Finally, we were able to identify 4 full-length hypo-thetical genes with proapoptotic activity.

• The Plant Pathology Journal
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• 제35권5호
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• pp.417-424
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• 2019

Melanose, caused by Diaporthe citri, is one of severe diseases in citrus, a major economic resource in Jeju island. To reduce the usage amount of organic synthetic fungicide, bio-sulfur was tested as an alternative chemical to control citrus melanose in the present study. Direct antifungal activity of bio-sulfur against D. citri was determined through in vitro experiment using artificial nutrient media. Disease severity of melanose on bio-sulfur pretreated citrus leaves was lower than that on untreated ones. To illustrate the mechanism of disease suppression by bio-sulfur, infection structures were observed with a fluorescent microscope and a scanning electron microscope. In fluorescent microscopic observation, most conidia rarely germinated. In addition, hyphal growth on leaves pretreated with bio-sulfur was inhibited compared to that on untreated ones. In scanning electron microscope images of bio-sulfur pretreated leaves, surfaces of most conidia were shrunk while hyphae were morphologically changed and frequently branched. Such microscopic observations were also found for leaves pretreated with a commercial fungicide Dithianon. These results suggest that bio-sulfur may be used to control citrus melanose as an environment friendly alternative to organic synthetic fungicides

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.288-288
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• 2010

Photonic Force Microscope (PFM) is a scanning force microscope using an optical trap with several piconewton. In PFM, we can have topological information from the bead position trapped in optical trap. Typically the resolutions of lateral and vertical position are 40 nm and 50 nm respectively. To improve the vertical resolution below 10 nm, we use resonance energy transfer which has 5nm resolution in distance. Here we show preliminary results, including performances of scanning bead and fluorescence imaging system.

• 한국환경과학회지
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• 제11권4호
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• pp.327-332
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• 2002

Optical microscope, SEM (Scanning Electron Microscopy) and fluorescent microscope were used for qualitative and morphological studies of the attached biomass on PE (polyethylene) substratum under anaerobic condition. It was shown by the observation of optical microscope that the initial attachment of biomass began in crevices of the surface of PE. The shape and structure of the attached biofilm could be observed by SEM photographs, but species of bacteria were and methanogens were not classified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation. It was estimated that methanogenic bacteria was also related to initial attachment of biomass under anaerobic condition.