• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.743-750
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• 1997

Direct measurement of the kinetics of free fatty acid transfer between phospholipid model membrane is technically limited by the rapid nature of the transfer process. Separation of membrane-bound fatty acid by centrifugation has shown that although the equilibrium distribution of free fatty acid is determined by this method, fatty acid transfer occurs too rapidly for accurate kinetic measurements. Recently fluorescence resonance energy transfer(FRET) assay has been developed to examine transfer of fatty acids between membranes. Donor membranes which has fluorescent fatty acid, anthroyloxy fatty acid(AOFA), is mixed with acceptor membranes which has non-interchangeable fluorescent quencher, nitrobenzo-xadiazol(NBD), using stopped flow apparatus. As the fluorescent fatty acids transfer from donor membrane to acceptor membrane, fluorescence intensity would be decreased and the rate and degree of fatty acid transfer can be analyzed. Fatty acid transfer between micelles is more complicated because of bile salt. Therefore in experiments with micelles, fluorescence self quenching assay is used. At high concentrations, a fluorophore tends to quench its own fluorescence causing a reduction in fluorescence intensity. Donor micelles contained self quenching concentrations of fluorophore and acceptor micelles had no fluorophore. Upon mixing of donor and acceptor micelles, the rate of transfer of the fluorophore from the donor to the acceptor was measured by monitoring the release in self quenching when its concentration in donor decreased over time.

• Applied Biological Chemistry
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• v.25 no.4
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• pp.224-231
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• 1982

${\alpha}-Tocopherol$ was found to be a fluorescent probe in determination of the phasetransition temperature of liposome. Since this was a discovery of a new aspect of ${\alpha}-tocopherol$ as an important biochemical molecule, its molecular spectroscopic characterization was carried out in order to obtain some informations on its spectral and, structural properties in various media, anticipating that the compound may entertain a wide applications in biochemical systems as a spectroscopic probe. Two species of α${\alpha}-tocopherol$, monomer and dimer, were found to exist in organic media, especially in solvents of nonhydrogen bonding ability. Monomer with maximum UV-absorption around $(291{\sim}294nm)$ is highly fluorescent, while dimer which is formed by intermolecular hydrogen bonds and absorbes with spectral peak at 298nm is nonfluorescent. ${\alpha}-tocopherol$ incorporated to liposome exhibits emission property quite different from that in various organic media showing broad and red-shifted fluorescence excitation and emission spectra. This spectral abnormality is to be interpreted to arise from chromanolate-type ion, H-dissociated ${\alpha}-tocopherol$.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.120-120
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• 2012

최근 주야간 산업현장의 근로자 안전성을 위한 식인성이 우수한 Hi-vis. 염색이 work-wear에 많이 적용되고 있으며, Hi-vis. 염색에서의 형광색상은 차별화된 패션성을 원하는 소비자에게도 레져용, 아웃도어용, 캐쥬얼 등에 많이 사용되고 있다. 형광염료는 주로 안료나 PET용 분산염료로의 전개가 일반적이며, 예전에는 형광안료 코팅을 통한 필름이나 테이프 등이 많이 사용되었으나 최근에는 의류에 직접 염색공정을 적용하는 기법으로 형광분산염료가 많은 용도에 적용된다. 이러한 고가시 산업용 work-wear는 주간에는 선명한 색상을 띄며, 야간에는 빛나는 재귀 반사의 성능을 지니며 대표적인 형광컬러는 Yellow, Red-Orange, Red, Yellow-Orange, Pink, Green, Yellow-Green 등 색상이 있다. 고가시성 안전의류(High Visibility Warning Clothing) 기준의 색도 좌표 및 일광 견뢰도 등 성능을 만족해야 하며, 대표적인 규격은 유럽의 EN-471로 일광, 마찰, 세탁, 땀, 드라이클리닝, 염소 등 견뢰도에 대한 각각의 합격기준이 있으며, 색도 및 형광팩터 등의 기준에 맞는 염색처방이 필요하다.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.26-28
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• 1990

Cw arc 램프로 펌핑하는 Alexandrite 레이저의 형광을 optical Spectrum Analyzer를 이용하여 측정하였다. Vibronic 천이에 해당하는 광대역 형광 스펙트럼이 관측되었고, arc 램프 입력에 따른 peak 형광의 세기 및 peak intensity 파장의 입력 power 의존성을 조사하였다. 형광의 세기는 입력 power에 따라 0.16 /kw의 비율로 증가하였고, peak intensity 파장은 입력 power가 5kw 까지는 5 nm/kw 비율로 장파장쪽으로 이동하였다.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.940-948
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• 2006

Fluorescence measurements of dissolved organic matter(DOM) have the superior advantages over other analysis tools for applying to water quality management. They are simple and fast and require minimal pretreatment of samples. Fluorescence index($F_{450}/F_{500}$), synchronous spectra, and fluorescence excitation-emission matrices(EEM) of various DOM samples were investigated to discriminate autochthonous/allochthonous composition, protein-like fluorescence, fulvic-like fluorescence, humic-like fluorescence, terestrial humic-like fluorescence by comparing among the real DOM samples of different origins with the help of literature. The samples used included standard purified DOM, lake, river and wastewater treatment effluent. The relative distribution of various DOM composition was derived from the ratios of each fluorescence region. The results were very consistent with those expected from the sample properties. Allochthonous and terrestrial humic-like fluorescence were more prominent in the samples with abundant soil-derived DOM components. In addition, the protein-like fluorescence property was more pronounced in the samples where strong algal or microbial activities were expected. It was also shown that the ratio of protein-like/terrestrial humic-like fluorescence obtained from synchronous spectrum and fluorescence EEM could be used as an indicator for the evaluation of wastewater treatment on the downstream water quality of rivers and for the prediction of the degree of algal/microbial activities in lakes. It is expected that the results of this study will provide the basic information to develop the future water quality management techniques using DOM fluorescence measurements.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.236-246
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• 2004

Artificial carious lesions in various depths were observed with visual examination using light transillumination, bite-wing radiography, laser fluorescence, and dye-enhanced laser fluorescence to determine the reproducibility, correlation of each diagnostic method, diagnostic sensitivity and diagnostic specificity. And optical densities according to demineralized times were measured whether laser fluorescence could be used as a quantitative diagnostic method. The following results were obtained whether laser fluorescence could be used for diagnosis of initial proximal caries. 1. Tau-c values of visual examination was 0.08 which showed lowest reproducibility and those of bite-wing radiography, laser fluorescence, dye-enhanced laser fluorescence were 0.60, 0.48, and 0.64, respectively which showed relatively high reproducibility. 2. The correlation between demineralization time and each examination was the highest in dye-enhanced laser fluorescence$({\gamma}=0.51)$ followed by laser fluorescence$({\gamma}=0.43)$, bite-wing radiograph$({\gamma}=0.35)$, and visual examination$({\gamma}=0.33)$. Dye-enhanced laser fluorescence and laser fluorescence showed significant correlation with demineralization time. 3. The sensitivity of laser fluorescence and dye-enhanced laser fluorescence for diagnosing approximal caries based on bite-wing radiography were 67%, 100% and those of specificity were 57%, 11% which showed diagnostic specificity was relatively lower than sensitivity. 4. The difference in optical density(DFR) between sound teeth and carious lesions according to lesion depth was high with dye-enhanced laser fluorescence compared with laser fluorescence. DFR measured with laser fluorescence according to changes in lesion depth was statistically significant but was not statistically significant with dye-enhanced laser fluorescence. Based on these results, laser fluorescence and dye-enhanced laser fluorescence have comparable diagnostic power as bite-wing radiography in early diagnosis of proximal caries.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1996.11a
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• pp.21-25
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• 1996

형광램프 시스템의 설계에서 안정기의 실패는 형광램프의 특성을 고려하는 것이 매우 중요하다. 특히, 시동시 과도특성에 근거한 형광램프의 동작모델을 등가회로로 알아내기 위해 실험에 의해 얻어진 결과를 등가희로 모델링과 Pspice 시뮬레이션에 의해 나타난 결과와 비교 분석하였으며, 특히 고주파용 형광램프의 동작 특성은 동작주파수, 형상, 램프 전압 및 전류값에 따라 차이가 많기 때문에 형광램프의 특성은 안정기의 특성을 고려한 형광램프 시스템에 동작특성 정합성에 매우 중요하다. 형광램프에 대한 고주파 특성으로 가장 많이 사용되는 주파수 영역(12Khz - 50Khz)에 대해서 실험, 분석한 결과 형광램프의 부(負)임피던스 동작특성을 파악하고 고주파 형광램프의 최적 특성치를 선택할 수 있는 방법을 제시하였다.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.826-831
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• 2018

This study presents fabrication of bi-compartmental particles labeled by multiple fluorescence. To compartmentalize fluorescent expression at the particle, two fluorescent dyes with less overlap of the excitation and emission spectra are selected. To ensure the fluorescence stability, the fluorescent dyes contain acrylate functional groups in the molecules so that they can be cross-linked together with monomers constituting the particle. Strong fluorescent expression and compartmentalization were observed at the particle fabricated using the selected fluorescent dyes through confocal microscopy. Furthermore, long-term fluorescence stability was verified by measuring fluorescent expression and intensity for 4 weeks. We anticipate that the bi-compartmental particles labeled by multiple fluorescence can be widely used for multi-target drug delivery system, analysis of 3 dimensional Brownian motion, and investigation of 3 dimensional complex self-assembled morphologies.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.221-221
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• 2016

최근에 희토류 이온이 도핑된 텅스텐산(tungstates) 형광체에 대한 연구가 재조명되고 있다. 텅스텐산 형광체는 우수한 광학적 특성과 높은 화학적 안정성을 나타내기 때문에 X-선 증강 스크린(X-ray intensifying screens), 광고판용 형광 램프, 발광 다이오드, 레이저, 섬광체(scintillator), 전계방출 디스플레이 영역에 그 응용성을 넓히고 있다. 본 연구는 모체 결정 MgWO4에 희토류 이온인 Tb3+와 융제(flux)의 몰 비를 변화 시켜 고상반응법을 사용하여 합성을 하였다. 합성한 형광체를 여기 파장 281 nm로 제어하였을 시, 545 nm의 녹색 발광 스펙트럼을 관찰 하였다. Tb3+이온이 0.10 mol일 때, 가장 발광 세기가 컸으며, 몰비가 증가 할수록 발광의 세기는 점차 커지다가 0.12 mol에서 작아졌다. 주 발광 신호 이외에도 489 nm, 586 nm, 621 nm에서 상대적으로 작은 발광 스펙트럼을 보였다. XRD를 통해 분석한 결정구조는 단사정계임을 알 수 있었으며 주 피크는 $23.9^{\circ}$에서 발생 하였고 이는 (110)면에서 발생한 회절 신호이다.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.205-210
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• 2013

Lumazine protein is a fluorescent protein isolated from the bioluminescent bacteria of Photobacterium species. To generate minimal size of lumazine protein with possessing fluorescent characteristic, the gene coding for the wild type N-terminal domain of lumazine protein (N-LumP 118) containing amino acids up to 118 from Photobacterium leiognathi was produced. In addition, the genes coding for the variant proteins of N-LumP 118, replaced with one tryptophan amino acid (N-LumP 118 V41W, S48W, T50W, D64W, and A66W), were also constructed by Polymerase Chain Reaction and Site Directed Mutagenesis. These proteins were expressed in Escherichia coli by transformation with recombinant plasmids and purified by 6X-His tagging system. Spectroscopic studies have show that the purified proteins are capable of binding to the fluorescent ligand 6,7-dimethyl-8-ribityllumazine, resulted in showing of fluorescent characteristic with the minimal size of protein. From these studies, the mutant proteins containing single tryptophan amino acid residue, possessing its own intrinsic flouophore character at the different position, will be able to the use as a probe for further studies to deduce their three dimensional structure and the binding modes.