• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.80-87
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• 2024

Silver diamine fluoride, which can arrest dental caries, is alkaline and may cause mild soft tissue irritation. Water-based silver fluoride has a neutral pH, which is closer to the physiological range, and is biocompatible for use in the oral environment. This study aimed to evaluate the effect of water-based silver fluoride on remineralizing early enamel lesions by comparing it with other fluoride agents through microhardness and quantitative light-induced fluorescence measurements. An in vitro study with intact bovine incisors was performed. Artificial enamel lesions were induced and subjected to microhardness and quantitative light-induced fluorescence testing. Specimens were randomly divided into 4 groups for treatment. The specimens in group I were treated with water-based silver fluoride and potassium iodide, group II with silver diamine fluoride and potassium iodide, group III with sodium fluoride varnish, and group IV with distilled water. After 8 days of pH cycling, the specimens were subjected to microhardness and quantitative light-induced fluorescence testing. Water-based silver fluoride and silver diamine fluoride showed the greatest increases in microhardness and quantitative light-induced fluorescence, with no significant differences between the two. Sodium fluoride varnish also exhibited a significant increase in microhardness and quantitative light-induced fluorescence, but the differences were smaller than those for water-based silver fluoride and silver diamine fluoride. Water-based silver fluoride is considered useful in a clinical setting for remineralizing enamel lesions, with the advantages of no risk of tissue burn and improved taste and smell.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1685-1688
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• 2002

• Journal of Microbiology
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• v.40 no.4
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• pp.319-326
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• 2002

Cellular DNA in prokaryotes is organized in nucleic acid-protein self-assemblies referred to as the nucleoid. The physical forces responsible for its stability inside the poor solvent properties of the cytoplasm and their functional implications are not understood. Studies on the organisation and functioning of the cytosol of cells largely rely on experimental protocols performed in highly dilute solutions using biochemically purified molecules, which is not a reliable substitute for the situation existing in vivo. Our current research interest is focused on the characterization of biological and physical forces determining the compaction and phase separation of DNA in Escherichia coli cytoplasm. We have emphasized the effect of excluded volume in solutions with high macromolecular concentrations (macromolecular crowding) upon self-association patterns of reactions. The prokaryotic cytosol was simulated by addition of inert polymer polyethylene glycol (PEG) (average molecular weight 20000), as an agent which afterwards facilitates the self-association of macromolecules. Fluorescence microscopy was used for direct visualization of nucleoids in intact cells, after staining with DAPI (4',6-diamidino-2-phenylindole dihydrochloride). Addition of the crowding agent PEG 20,000, in increasing concentrations generated progressively enhanced nucleoid compaction, the effect being stronger in the presence of 0.2 M NaCl and 5 mM MgCl$\_$2/. Under these conditions, the nucleoids were compacted to volumes of around 2 ㎛$\^$3/ or comparable sizes with that of living cells.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.117.1-117.1
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• 2011

We have demonstrated Forst-type resonance energy transfer (FRET) in the quasi-solid type dye-sensitized solar cells between organic fluorescence materials as an energy donor doped in polymeric gel electrolyte and ruthenium complex as an energy acceptor on surface of $TiO_2$. The strong spectral overlap of emission/absorption of energy donor and acceptor is required to get high FRET efficiency. The judicious choice of energy donor allows the enhancement of light harvesting characters of energy acceptor in quasi-solid dye sensitized solar cells which increase the power conversion efficiency. The enhanced light harvesting effect by the judicious choice/design of the fluorescence materials and sensitizing dyes permits the enhancement of photovoltaic performance of DSSC.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.77-83
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• 2005

The influence of fluorescence, scattering, and absorbance in turbid material by light scattering was interpreted by the scattered fluorescence intensity and wavelength. The effect of optical property in scattering media was investigated. It is very important to study the charge coupled device(CCD) in spectrometry because we can use the molecular energy level, molecular structure, absorption or emission, intermolecular reaction, weakly bound molecular energy, photochemistry, fluorescence and photodynamic therapy. CCD is very essential to study the molecular structure and medical engineering combined laser spectroscopy in the modem physical and chemistry. Accordingly, this study has designed and manufactured the electromagnetic spectrometry with CCD, and has analyzed the hematoporphyrin derivative.

• Journal of Plant Biology
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• v.31 no.3
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• pp.217-226
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• 1988

Effects of simazine [2-chloro-4,6-bis(methylamino)-s-triazine] on the photochemical reactions of isolaed spinach chloroplasts and crude thylakoids of Anabaena inequalis UTEX B-381 were compared. Simazine inhibited photosynthetic O2 evolution and increased the chlorophyll fluorescence in whole cells of Anabaena. The electron transfer from diphenylcarbazide to 2,6-dichlorophenolindophenol was inhibited by simazine treatment in spinach chloroplasts, but not in crude thylakoids of Anabaena. In spinach chloroplasts, the chlorophyll fluorescence was increased by simazine treatment in the presence of diphenylcarbazide and ferricyanide, but not in the presence of diphenylcarbazide and silicomolybdate. In crude thylakoids of Anabaena, simazine treatment did not increase the chlorophyll fluorescence in the presence of either diphenylcarbazide and silicomolybdate, or diphenylcarbazide and ferricyanide. There results suggest that the inhibitory site of simazine on photosynthetic electron transport chain of anabaena is different from that of spinach chloroplasts. And there may be a possiblity that the inhibition site of simazine in Anabaena lies on the donor side of photosystem II, before the site of electron donation by diphenylcarbazide.

• Journal of Photoscience
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• v.6 no.4
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• pp.193-198
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• 1999

Various arylidene- or alkylidenemalononitriles are condensed with electrophilic ethylenes to obtain polycyanoaniline derivatives. All the anilines showed strong fluorescence and the fluorescence intensities was evaluated to the effect of substituents.

• Journal of Photoscience
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• v.12 no.3
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• pp.113-117
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• 2005

Spectroscopic investigations on the interaction of gabapentin (GBP) with bovine serum albumin (BSA) were reported. The association constant of GBP-BSA system was determined at different temperatures (298, 302, 306 and 311 K) based on the fluorescence quenching results. The GBP was found to quench the fluorescence of BSA through static mechanism. Thermodynamic parameters, the standard enthalpy change, $({\Delta}H^o)$ and the standard entropy change $({\Delta}S^o)$ were observed to be $-9.61{\pm}0.008\;kJ\;mol^{-1}$ and $3.58{\pm}0.011\;Jmol^{-1}K{-1}$ respectively. These indicated that the hydrophobic and electrostatic forces played a role in the interaction of GBP with BSA. The negative value of ${\Delta}G^o$ revealed that the binding reaction is spontaneous. The circular dichroism studies indicated the conformational changes in BSA upon interaction with GBP. The effect of some metal ions on the binding constant was also investigated.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2988-2996
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• 2011

Shape memory polyurethane (SMPU), grafted with a fluorescent dye (Rhodamine, Mehylene violet, or Fluorescein) through an allophanate linking, was tested for the fluorescence and the shape recovery effect. The main chain of SMPU was composed of 4,4'-methylenebis(phenylisocyanate) (MDI), poly(tetramethyleneglycol) (PTMG), and 1,4-butanediol (BD), and a fluorescent dye was connected through a second MDI linked to the carbamate moiety of the main chain. Three series of SMPU, differing according to their dye content, were prepared to compare their shape recovery and fluorescence properties. In tensile mechanical property, maximum stress increased up to 350% compared to the linear SMPU, and strain remained above 2000%. Shape recovery went to as high as 97%, and remained almost same after repetitive shape recovery test cycles. Finally, the fluorescence emission of SMPU was demonstrated in the luminescence spectrum and fluorescent light emission pictures. In addition, the response of SMPU to external stimuli such as metal ions was investigated.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3261-3266
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• 2011

The interaction of bilobalide (BB) and ginkgolides B (GB) with bovine serum albumin (BSA) was investigated by fluorescent technique and UV/vis absorption spectroscopy. The results showed that BB and GB could intensively quench the fluorescence of BSA through a static quenching procedure. The binding constants (Ka) and the average binding distance between the donor (BSA) and the acceptor (ginkgolides) were obtained ($r_{BB}$ = 5.33 nm and $r_{GB}$ = 4.20 nm) by the theory of non-radiation energy transfer, and then the thermodynamic parameters such as ${\Delta}S^0$ (0.17-0.32 kJ/mol), ${\Delta}G^0$ (-20.76 ~ -17.79 kJ/mol) and ${\Delta}H^0$ (32.47-76.52 kJ/mol) could be calculated, respectively. All these results revealed that the interaction of BB and GB with BSA were driven mainly by hydrophobie force. The synchronous fluorescence spectroscopy was applied to examine the effect of two ginkgolides on the configuration of BSA. The configuration alteration of BSA could be induced by the hydrophobicitv environment of tyrosine with the increase of the drug concentration.