• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1509-1512
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• 2008

Monomer and aggregate of $Bebq_2$ give fluorescence at 492 and 511 nm at 12 K, respectively. Intense T1 emission with vibronic structure was observed from $Bebq_2$ and $Alq_3$ below 70 K by heavily doping with phosphorescent $Ir(ppy)_3$. Energy transfer from $Ir(ppy)_3$ was clarified by photoluminescence excitation spectra.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.296-301
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• 1999

Different papers such as toilet and towel tissue, newsprint and copy paper made from reclaimed fibres were characterized using UV-VIS reflectance and fluorescence spectroscopy. The emission properties of the extracts of the papers were also evaluated. Photochemical irradiation at ambient temperatures, and thermal aging of the copy papers at 105$^{\circ}C$ and 150$^{\circ}C$ were performed. Post-colour numbers (PC) were calculated from the reflectance values measured from the corresponding UV-VIS reflectance spectra. Light absorption coefficient spectra were calculated before and after irradiation, and the changes in absorption coefficient were related to the content of chromophores in the papers. Photochemical and thermal discolouration of the copy papers, similar to that of virgin fibres, was readily observed. The influence of changes in the concentrations of fluorescent brightening agents and dyes on the spectral properties was also assessed. Photostabilization studies of the copy papers were performed with the use of polymer additives polyethylene glycol (PEG) and polytetrahydrofuran (PTHF).

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3241-3246
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• 2010

NHERF ($Na^+/H^+$ exchanger regulatory factor) and E3KARP (NHE3 kinase A regulatory protein) play important roles in membrane targeting, trafficking and sorting of ion channels, transmembrane receptors and signaling proteins in many tissues. Each of these proteins contains two PDZ (PSD-95/Dlg-1/ZO-1) domains, which mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. The interaction between NHERF and E3KARP was investigated by surface plasmon resonance spectroscopy (BIAcore), fluorescence measurement, His-tagged pull-down experiment, and size-exclusion column (SEC) chromatography. BIAcore experiments revealed that NHERF bound to E3KARP with an apparent $K_D$ of 7 nM. Fluorescence emission spectra of the NHERF-E3KARP complex suggested that the tight interaction between these proteins was accompanied by significant conformational changes in one or both. The CD spectra of NHERF and E3KARP show that the conformational changes of these proteins were dependent on pH and temperature. These results implicate that the NHERF-E3KARP complex allows intracellular signaling complexes to form through PDZ-PDZ interactions.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.105-110
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• 2012

A europium (III)-sensitized, spectrofluorimetric (FL) method is presented for the determination of sparfloxacin (SPAR) using an anionic surfactant, sodium dodecyl benzene sulphonate (SDBS). The method is based on the strong fluorescence (FL) enhancement of SPAR after the addition of $Eu^{3+}$ ions as fluorescence probes. The experimental results indicated that the FL intensity of the SPAR-$Eu^{3+}$ system was enhanced markedly by SDBS. The maximum FL emission signal was obtained at about 615 nm when excited at 372 nm. The experimental conditions that affected the FL intensity of the SPAR-$Eu^{3+}$-SDBS system were optimized systematically. The enhanced FL intensity of the system exhibited a good linear relationship with the SPAR concentration over the range of $1.5{\times}10^{-9}-1.2{\times}10^{-7}mol\;L^{-1}$ with a correlation coefficient (r) of 0.9987. The limit of detection ($3{\delta}$) was $4.15{\times}10^{-10}mol\;L^{-1}$ with a relative standard deviation (RSD) of 1.65%. This method was successfully applied for the determination of SPAR in pharmaceuticals, and human serum and urine samples with higher sensitivity, wide dynamic range and better stability. The possible interaction mechanism of the system is also discussed in detail by ultraviolet absorption spectra and FL spectra.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.193-201
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• 1996

In order to study the role of C-terminal aromatic region of T4 endonuclease V in the interaction with substrate DNA, NMR and Fluorescence spectrum were recorded. Analysis of flu orescence emission spectra showed that C-terminal region of T4 endonuclease V is in or very near the binding site. In the HSQC spectrum of $^{15}N$-Tyr-labeled T4 endonuclease V*DNA complex, the broadening of a peak was observed. It is presumed that this peak corresponds to one among three tyrosine residues which belong to the WYKYY segment of C-terminal region of T4 endonuclease V. Interactions of peptide fragments consisting of C-terminal residues of T4 endonuclease V with DNAs(TT-, T^T-DNA) were investigated by NMR and Fluorescence experiment. The results suggest that two peptide fragments themselves bind to DNAs and their binding pattern is not an intercalation mode.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3610-3613
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• 2011

CdS nanoparticles (NPs) were synthesized in an aqueous phase in order to investigate their spectral behaviors as efficient fluorescence resonance energy transfer (FRET) donors for various organic dye acceptors. Our prepared CdS NPs exhibiting strong and broad emission spectra between 480-520 nm were able to transfer energy in a wide wavelength region from green to red fluorescence dyes. Rhodamine 6G (Rh6G), rhodamine B (RhB), and sulforhodamine 101 acid (Texas red) were tested as acceptors of the energy transfer from the CdS NPs. The three dyes and synthesized CdS NPs exhibited good FRET behaviors as acceptors and donors, respectively. Energy transfers from the CdS NPs and organic Cy3 dye were compared to the same acceptor Texas red dye at different concentrations. Our prepared CdS NPs appeared to exhibit better FRET behaviors comparable to those of the Cy3 dye. These CdS NPs in an aqueous solution may be efficient FRET donors for various organic dyes in a wide wavelength range between green and red colors.

• Journal of the Korean Chemical Society
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• v.34 no.1
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• pp.91-97
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• 1990

Copolymers (PSAA) of styrene-acrylic acid were prepared through a free radical mechanism using azobisisobutyronitrile as an initiator. The fluorescence emission spectra of PSAA and the styrene-acrylic acid copolymers complexed with $Eu^{3+}$ (PSAA-Eu) were studied. The excimer fluorescence, centered at 330 nm, increases when the styrene mole fraction increases. Since the excimer fluorescence intensities of PSAA-EU, PSAA-Tb and PSAA-Eu-Tb were almost same, it appears that the kind of metal ion does not affect the excimer fluorescence. An interpretation of the results which takes into account the statistical composition of the copolymers, indicates that energy migration can occur from isolated to non-isolated styrene units.

• BMB Reports
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• v.35 no.5
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• pp.488-493
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• 2002

IgY was separated from a hen's egg yolk that was immunized with Helicobacter pyroli. The anti-H. pyroli IgY activity at acidic pH and the suppressive effect of polyol on acid-induced inactivation of IgY were investigated. Sorbitol and xylitol were used as polyols. IgY was quite stable at pH 5~7. Irreversible inactivation of IgY was observed at pH below 4, and proceeded rapidly at pH below 3. The acid stability of IgY was enhanced in the presence of 30% sorbitol or above. In a 50% aqueous sorbitol solution, an acid-induced inactivation was almost completely suppressed at pH 3. However, the improvement of IgY activity was not observed in the aqueous xylitol solution. IgY showed almost the same activity as native IgY when sucrose was substituted for sorbitol. On the other hand, the xylitol replacement with sucrose did not enhance the acid stability of IgY. The acid-induced inactivation of IgY was related to tryptophyl fluorescence. Fluorescence emission spectra suggested that structural changes near the tryptophan residues may occur under acidic conditions. An increase in sorbitol concentration induced a blue shift. The fluorescence emission of IgY in a 50% sorbitol solution had a peak at 330 nm, which was the same emission peak that was exhibited by native IgY. Sorbitol could, therefore, be used as a good stabilizer of IgY under acidic conditions.

• Journal of Photoscience
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• v.9 no.2
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• pp.512-514
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• 2002

S-aminolevulinic acid (ALA) is a new kind drug used in photodynamic therapy. ALA-PDT have successfully used in superficial malignancies and some skin diseases. Here the effects of ALA-PDT were studied on leukemia cells and hepatoma cells to explore the application on different kind cancers. It was found from the fluorescence emission spectra, that after ALA incubation the sensitizer - protoporphyrin IX (PpIX) was endogenously produced in both leukemia and hepatoma cells. The fluorescence images showed that the PpIX distribute in cytoplasm. However the efficiency of ALA photodynamic inactivation to two cell lines was different. The leukemia cells were more sensitive for ALA-PDT than hepatoma cells, revealing that the ALA-PDT effect is cell line dependent. However by using ALA-Hexyl ester (He-ALA) instead of ALA, the cell photo-inactivation was improved. The PDT efficiency of He-ALA was 10 times high than that of ALA, showing He-ALA is a very promising drug in ALA-PDT.

• Publications of The Korean Astronomical Society
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• v.12 no.1
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• pp.85-98
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• 1997

The A-X (0-0) band of CS, which appears in high dispersion IUE spectra of comets Halley (1982i) and Wilson (19861), has been investigated in detail. We developed models, which include fluorescence and collisional processes We found that in order to account for the observed emission band precisely, IUE tracking errors should be included in line shape calculations it has been found that rotational excitation by electrons is a dominant process in determining populations of rotational ground states. We derived an electron density of $2.0\times10^4/cm^3$ at several thousand kilometers from the comet Wilson's nucleus by examining collisional influence on the CS band structure. We presented a band model for the 0-0 band of $C^{34}S$ and discussed the detectability of $^{34}S$ spectroscopically.