• Molecules and Cells
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• v.27 no.2
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• pp.211-215
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• 2009

Toll-like receptors (TLRs) play a critical role in sensing microbial components and inducing innate immune and inflammatory responses by recognizing invading microbial pathogens. Lipopolysaccharide-induced dimerization of TLR4 is required for the activation of downstream signaling pathways including nuclear factor-kappa B ($NF-{\kappa}B$). Therefore, TLR4 dimerization may be an early regulatory event in activating ligand-induced signaling pathways and induction of subsequent immune responses. Here, we report biochemical evidence that 6-shogaol, the most bioactive component of ginger, inhibits lipopolysaccharide-induced dimerization of TLR4 resulting in the inhibition of $NF-{\kappa}B$ activation and the expression of cyclooxygenase-2. Furthermore, we demonstrate that 6-shogaol can directly inhibit TLR-mediated signaling pathways at the receptor level. These results suggest that 6-shogaol can modulate TLR-mediated inflammatory responses, which may influence the risk of chronic inflammatory diseases.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1303-1308
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• 2001

A series of catalysts, NiSO4/TiO2, for ethylene dimerization was prepared by the impregnation method using aqueous solution of nickel sulfate. On the basis of the results obtained from X-ray diffraction, the addition of NiSO4 shifted the transition of TiO2 from the anatase to the rutile phase toward higher temperatures due to the interaction between NiSO4 and TiO2. Nickel sulfate supported on titania was found to be very active even at room temperature. The high catalytic activity of NiSO4/TiO2 closely correlated with the increase of acidity and acid strength due to the addition of NiSO4. It is suggested that the active sites responsible for ethylene dimerization consist of low valent nickel, Ni+, with an acid.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1297-1298
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• 2001

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1029-1030
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• 2005

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.735-738
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• 2009

• BMB Reports
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• v.53 no.3
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• pp.133-141
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• 2020

The epidermal growth factor receptor (EGFR), a member of the ErbB family (EGFR, ErbB2, ErbB3 and ErbB4), plays a crucial role in regulating various cellular responses such as proliferation, differentiation, and survival. As a result, aberrant activation of EGFR, mostly mediated through different classes of genomic alterations occurring within EGFR, is closely associated with the pathogenesis of numerous human cancers including lung adenocarcinoma, glioblastoma, and colorectal cancer. Thus, specific suppression of oncogenic activity of mutant EGFR with its targeted drugs has been routinely used in the clinic as a very effective anti-cancer strategy in treating a subset of tumors driven by such oncogenic EGFR mutants. However, the clinical efficacy of EGFR-targeted therapy does not last long due to several resistance mechanisms that emerge in the patients following the drug treatment. Thus, there is an urgent need for the development of novel therapeutic tactics specifically targeting mutant EGFR with the focus on the unique biological features of various mutant EGFR. Regarding this point, our review specifically emphasizes the recent findings about distinct requirements of receptor dimerization and autophosphorylation, which are critical steps for enzymatic activation of EGFR and signaling cascades, respectively, among wildtype and mutant EGFR and further discuss their clinical significance. In addition, the molecular mechanisms regulating EGFR dimerization and enzymatic activity by a key negative feedback inhibitor Mig6 as well as the clinical use for developing potential novel drugs targeting it are described in this review.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1273-1279
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• 2007

The NiSO4 supported on Fe2O3 catalysts were prepared by the impregnation method. No diffraction line of nickel sulfate was observed up to 30 wt %, indicating good dispersion of nickel sulfate on the surface of Fe2O3. The addition of nickel sulfate to Fe2O3 shifted the phase transition of Fe2O3 (from amorphous to hematite) to higher temperatures because of the interaction between nickel sulfate and Fe2O3. 20-NiSO4/Fe2O3 containing 20 wt % of NiSO4 and calcined at 500 oC exhibited a maximum catalytic activity for ethylene dimerization. The initial product of ethylene dimerization was found to be 1-butene and the initially produced 1-butene was also isomerized to 2-butene during the reaction. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method.

• Analytical Science and Technology
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• v.12 no.3
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• pp.209-217
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• 1999

To elucidate the decay of the rose bengal (RB) sensitized and thiourea (TU) supersensitized photocurrent, spectroscopic analyses of the dye solution were performed. Absorption and fluorescence spectroscopic analyses of sensitizing solution before and after irradiation enabled to conform the new mechanism of the photocatalytic dimerization between RB and TU. And it was also found that the geometrical arrangement of the transition dipole moment is oblique and the angle between the dipoles is $124^{\circ}$ in the dimer of dye molecules.

• Analytical Science and Technology
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• v.11 no.1
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• pp.20-28
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• 1998

Fluorimetric and absorption spectroscopic studies were performed to elucidate the photocurrent decay with time in the conversion process of solar energy into electrical energy using a photoelectrochemical cell containing rose bengal as a sensitizer, and allylthiourea as a supersensitizer. Spectra of dye solution before and after irradiation revealed a new photocatalytic dimerization reaction between sensitizer and supersensitizer. It was also found that the geometrical arrangement of the transition dipoles is oblique in the dimer of dye molecules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.541-544
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• 1999

We synthesised a novel photo-alignment material of PCEMA (poly(cinnamolyethyl methacrylate)) on photo-dimerization reaction. Next we investigated the electro-optical (EO) characteristics of photo-aligned twisted nematic (TN)-liquid crystal display (LCD) with linearly polarized ultraviolet (UV) light irradiation on PCEHA surface. The excellent voltage-transmittance characteristics of photo-aligned TN-LCD on PCEMA surface were obtained. The threshold voltage of photo-aligned TN-LCD decreases with increasing the UV light irradiation time on PCEMA surface. Also, the response time of photo-aligned TN-LCD on PCEMA surface is almost the same as rubbing-aligned TN-LCD.