• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2415-2418
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• 2008

Polydiacetylenes (PDAs) are very attractive chemical substances which have distinctive features of color change and fluorescence emission by thermal or chemical stress. Especially, when PDAs contact with solutions of a particular pH, such as a strong alkaline sodium hydroxide (NaOH) solution or a strong acidic hydrogen chloride (HCl) solution, PDAs change their color from non-fluorescent blue to fluorescent red. In this study, we propose a novel method to detect alkaline pH using PDAs and NaOH solutions by hydrodynamic focusing on a microfluidic chip. Preliminary results indicate that the fluorescent intensity of PDAs increases in respond to the NaOH solution concentrations. Also, the fluorescence is quenched back when the PDAs are in contact with a HCl solution. These results are useful in a microfluidic PDA sensor chip design for pH detection.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.553-557
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• 2013

The stretching vibration of OH of ice Ih is studied by Car-Parrinello molecular dynamics in regarding the effect of mixed H/D contamination while the vibrational spectrum is considered by velocity-velocity autocorrelations of the sampled ensemble. When hydrogen atoms are immersed randomly into the deuterated ice, a typical vibrational frequency of OH stretching mode is observed to be similar to that from the pure $H_2O$ ice. When focusing on the correlation of isolated neighboring OH stretching, a narrower and blue shifted peak is observed at the high frequency range as a result of the screening from the complex many body correlations by $D_2O$ environment. It is also specifically related to the symmetric intermolecular correlations between neighboring OH stretching modes. More enhanced high frequency range can be explained by the expansion of such two body correlations to collective many body correlations among all possible OH stretching modes. This contribution becomes important when it involves in chemical interactions via excitation of such vibrational states.

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.701-704
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• 2000

Fluorene and carbazole-containing distyrylarylene model and polymeric fluorophores were prepared by reacting 2,7-dibromo-9-butylfluorene and 3,6-dibromo-9-butylcarbazole with styrene and divinylbenzene using the Heck reaction for the chemiluminesc ence. The UV-vis absorbance, photoluminescence (PL) as well as the chemiluminescence (CL) characteristics of the model and polymeric fluorophores were measured. Sodium salicylate-catalyzed reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide produced a strong chemiluminescent blue light emission with 439-489 nm in the presence of the fluorophore. The wave-length of CL light was similar to that of photoluminescence. The chemiluminescent intensity was decayed according to the exponential equation.The glow of CL maintained more than 12 hr and was visible with naked eye.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.704-708
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• 1993

The intramolecular charge transfer (ICT) phenomena of the photoexcited 2-biphenylcarboxylic acid (2BPCA) and 4-biphenylcarboxylic acid (4BPCA) have been investigated in some surfactant micellar solutions. The ICT emission of 4BPCA and 2BPCA in aqueous solution at sufficiently low pH (1-3) has been observed to be markedly quenched and blue-shifted upon addition of a cationic surfactant, cetyltrimethylammonium chloride (CTAC) in contrast to little change in anionic sodium dodecyl sulfate (SDS) and neutral Brij 35. An anionic emission band has been observed to be enhanced at expense of the ICT emission as a function of the concentration of CTAC. These results with the micellar effects on the fluorescence decay kinetics of 4BPCA suggest that formation of the ICT state of the excited acids is inhibited by CTAC-induced proton transfer as well as the decrease in the polarity and/or hydrogen-bonding ability of the micellar microenvironment entrapping the acids.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.727-731
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• 2001

Conjugated-non-conjugated alternating block copolymers containing distyrylarylene units were synthesized via Wittig reaction for chemiluminescent fluorophores. The polymers were differentiated from others by the presence of aromatic unit in the chromophoric block. When UV-VIS, photoluminescence and chemiluminescence spectra of these materials were compared with copolymers, a strong bathochromic effect was observed. A more pronounced red shift and higher chemiluminscence efficiency were observed in the polymer with anthracene ring. Sodium salicylate-catalyzed reaction of bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate with hydrogen peroxide produced a strong chemiluminescence from blue to yellow-green light emission with wavelength of 450-537 nm in the presence of the fluorophore. The chemiluminescent intensity decayed exponentially. The glow of chemiluminescence maintained more than l2 hr and was visible with the naked eye.

• Journal of Life Science
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• v.28 no.9
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• pp.1092-1099
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• 2018

This study was orchestrated with the purpose of uncovering new nutraceutical resources possessing biological activities in the plant kingdom. To fulfill our objective, we analyzed several plant extracts and selected five species possessing powerful anti-oxidative activity. The anti-oxidative effect of these five plants, Apios fortunei Maxim., Colubrina arborescens Sarg., Croton caudatus Geiseler, Osmanthus matsumuranus Hayata and Schima noronhae Reinw. ethanol extracts were then evaluated by using in vitro assay, cell model system, and Western blot analysis of target proteins. As the results, all of them possessed the potent scavenging activity against 1,1-diphenyl-2-picryl hydrazyl (DPPH), similar with that of ascorbic acid, used as a common positive control. Moreover, they strongly inhibited hydrogen peroxide ($H_2O_2$)-induced reactive oxygen species (ROS), in a dose-dependent manner, in RAW 264.7 murine macrophage cells. Furthermore, they induced the protein expression of an anti-oxidative enzyme, heme oxygenase 1 (HO-1), and its upstream transcription factor, nuclear factor-E2-related factor 2 (Nrf2). Taken together, these results indicate that these five plants possess potent anti-oxidative activity and thus appear to be useful sources as potential anti-oxidant agents. Therefore, they might be utilized as promising materials in the field of nutraceuticals.

• Microbiology and Biotechnology Letters
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• v.41 no.4
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• pp.433-441
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• 2013

In this study, the anti-oxidative, anti-inflammatory, anti-melanogenic activities of Endlicheria anomala (Nees) Mez methanol extract (EAME) were evaluated by use of in vitro assays and cell culture model systems. The results revealed that EAME scavenges various radicals such as 1,1-diphenyl-2-picryl hydrazyl hydrogen peroxide induced reactive oxygen species, and lipopolysaccharide induced nitric oxide. Furthermore, EAME induced the expression of anti-oxidative enzymes such as heme oxygenase 1, thioredoxin reductase 1, NAD(P)H dehydrogenase 1, and their upstream transcription factor, nuclear factor-E2-related factor 2. Moreover, EAME inhibited in vitro DOPA oxidation and 3-isobutyl-1-methylxanthine induced melanogenesis in B16F10 cells. Its anti-melanogenic activity will have originated from the inhibition of tyrosinase enzyme activity and melanogenesis related protein expression. Taken together, these results provide the important new insight that E. anomala possesses various biological activities such as anti-oxidative, anti-inflammatory, and anti-melanogenic. Therefore, it might be utilized as a promising material in the fields of nutraceuticals and cosmetics.

• Journal of Life Science
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• v.24 no.7
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• pp.713-720
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• 2014

In this study, the antioxidative and anti-inflammatory activities of Ardisia arborescens ethanol extract (AAEE) were evaluated using in vitro assays and a cell culture model system. AAEE exhibited potent scavenging activity against 1,1-diphenyl-2-picryl hydrazyl (DPPH), similar to ascorbic acid, which was used as a positive control. Moreover, AAEE effectively suppressed lipopolysaccharide (LPS)- and hydrogen peroxide ($H_2O_2$)-induced reactive oxygen species (ROS) in RAW 264.7 cells. Furthermore, AAEE induced the expression of antioxidative enzymes, heme oxygenase 1 (HO-1), and thioredoxin reductase 1 (TrxR1), in addition to their upstream transcription factor, nuclear factor-E2-related factor 2 (Nrf2), in a dose-dependent manner. The upstream signaling pathways of mitogen-activated protein kinases (MAPKs) might regulate the modulation of HO-1, TrxR1, and Nrf2 expression. On the other hand, AAEE inhibited LPS-induced nitric oxide (NO) formation, without cytotoxicity. Suppression of NO formation was the result of AEEE-induced down-regulation of inducible NO synthase (iNOS). The suppression of NO and iNOS by AAEE might be modulated by their upstream transcription factor, nuclear factor (NF)-${\kappa}B$, and activator protein (AP)-1 pathways. Taken together, these results provide important new insights into the antioxidative and anti-inflammatory activities of A. arborescens. AAAEE might represent a promising material in the field of nutraceuticals.

• Journal of Life Science
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• v.27 no.7
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• pp.783-789
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• 2017

Malus melliana (Hand.-Mazz.) Rehder (M. melliana) is a Chinese plant that belongs to the Rosaceae family. There have been no previous reports regarding its bioactivity. In this study, the anti-oxidative and anti-inflammatory activities of M. melliana ethanol extract (MMEE) were evaluated using a 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity assay, reactive oxygen species (ROS) scavenging activity assay, nitric oxide (NO) inhibitory activity assay, and the analysis of related protein expressions through Western blot hybridization. MMEE showed potent scavenging activity against DPPH, similar to ascorbic acid, a well-known anti-oxidative agent, which was used as a positive control. MMEE also inhibited hydrogen peroxide-induced ROS in RAW 264.7 cells. Moreover, MMEE induced the expression of an anti-oxidative enzyme, heme oxygenase 1, and its upstream transcription factor, nuclear factor E2-related factor-2, in a dose-dependent manner. On the other hand, MMEE was associated with a reduction in NO production, which was induced by the lipopolysaccharide treatment of RAW 264.7 cells. The expression of inducible nitric oxide synthase, which is the upstream regulator of NO production, was also inhibited. Taken together, these results suggest that MMEE has anti-oxidative and anti-inflammatory properties, thus appearing to be a potential anti-oxidant and anti-inflammatory agent. The further identification of active compounds that confer the biological activities of MMEE may be necessary.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.67-74
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• 2016

The Prussian Blue Analogue(PBA) has three dimensional structure and the metal - organic framework material, and it has a variety configurations depending on the type of organic ligands. PBA has been receving an attention in the fields of biosensors, optical, catalytic, and hydrogen storage device. Also, it is an environmental friendly substance with a chemical stability. In addition, PBA is widely used in the filed of adsorption art since we can adjust the size of the fine pores. In this study, we synthesized $Mn_3[Fe(CN)_6]_2$, an organometallic framework chains by using a hydrothermal synthesis method. We used $K_4[Fe(CN)_6]$ and $MnCl_2$ as precursors. We also produced a manganese iron oxide, by baking the synthesized material. The effect of the size and shape of the particles was examined by controling pH of the precursor solution, the molar concentration of the precursor, and reaction time as the experimental variables. Synthesized absorbent was analyzed by XRD, SEM, FT-IR, UV-Vis, and TG / DTA to evaluate the adsorption properties of several dyes.