• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1042-1047
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• 1998

The fluorescence excitation (FE) spectrum of the S1-S0 (1B2-1A1) transition of dimethyldiazirine cooled in supersonic jet expansions has been obtained. Dispersed fluorescence (DF) spectra have also been taken for some prominent features of the FE spectrum. Vibrational analyses of the FE and DF spectra with the help of an ab initio molecular orbital calculation lead to some new vibrational assignments and refined fundamental frequencies.

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1043-1045
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• 1995

The overtone of the ν2 vibrational mode in Cr(CO)6 are observed for the first time in cyclohexane and methanol at both the 266 and 213 nm excitations. The appearance of the overtones due to the displacement of the electronic excited state with respect to the ground state along the ν2 vibrational mode is interpreted in terms of wavepacket concept and molecular orbital (MO) theory. Our Raman results suggest a new interpretation for the excited state potential.

• BMB Reports
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• v.37 no.3
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• pp.304-313
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• 2004

Three-dimensional (3D) models for the 65-kDa activated Cry4A and Cry4B $\delta$-endotoxins from Bacillus thuringiensis subsp. israelensis that are specifically toxic to mosquito-larvae were constructed by homology modeling, based on atomic coordinates of the Cry1Aa and Cry3Aa crystal structures. They were structurally similar to the known structures, both derived 3D models displayed a three-domain organization: the N-terminal domain (I) is a seven-helix bundle, while the middle and C-terminal domains are primarily comprise of anti-parallel $\beta$-sheets. Circular dichroism spectroscopy confirmed the secondary structural contents of the two homology-based Cry4 structures. A structural analysis of both Cry4 models revealed the following: (a) Residues Arg-235 and Arg-203 are located in the interhelical 5/6 loop within the domain I of Cry4A and Cry4B, respectively. Both are solvent exposed. This suggests that they are susceptible to tryptic cleavage. (b) The unique disulphide bond, together with a proline-rich region within the long loop connecting ${\alpha}4$ and ${\alpha}5$ of Cry4A, were identified. This implies their functional significance for membrane insertion. (c) Significant structural differences between both models were found within domain II that may reflect their different activity spectra. Structural insights from this molecular modeling study would therefore increase our understanding of the mechanic aspects of these two closely related mosquito-larvicidal proteins.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.582-584
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• 2004

The light-emitting properties of poly(2-triethylgermyl-1,4-phenylenevinylene) (TEG-PPV) are compared with those of the silyl-substituted PPV homologue, poly(2-trimethylsilyl-1,4phenylenevinylene) (TMS-PPV). The precursor polymer is solution-processable. After carrying out thermal elimination on the precursor polymer film, the resulting fully conjugated polymer film was found to exhibit high thermal stability in air, and absorption that is shifted to the longer wavelength region owing to the extension of the n-conjugated system. TEG-PPV exhibits efficient green light emission; the maximum PL emission of a TEG-PPV thin film was found to be at 515 nm. The HOMO and LUMO energy levels were also determined using photo-emission spectroscopy. The performance of the TEG-PPV EL device was found to be comparable to that of the TMS-PPV device.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.630-633
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• 2003

The mussel adhesive protein Mefp-1 is a natural, strong and durable adhesive that is stable under corrosive, saline conditions. Mefp-1 is found in the marine mussel Mytilus edulis and it has a molecular weight of ca. 130,000. The primary structure is mainly composed of repeating decapetides: Ala-Lys-Pro -Ser-Tyr Hyp-Hyp-Thr-DOPA-Lys. To elucidate the mechanism by which Mefp-1 bonds to metal surfaces, we have used surface-enhanced Raman spectroscopy to study the interactions of peptides related to the Mefp-1 decapeptide repeat with gold surfaces. We have concluded that the tyrosine residue and the carboxyl terminus interact strongly with the gold surface, and that proline and hydroxyproline constrain the conformations of the peptides, thereby limiting the types of possible interactions of the functional groups with the gold surface.

• KSBB Journal
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• v.15 no.3
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• pp.293-298
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• 2000

${\beta}$-Glucan a kind of polysaccharide which is particularly abundant in Agaricus blazei is known as the bioactive materials especially anticancer agents. The process development of the isolation and the purification process of water soluble ${\beta}$-glucans from A. blazei was achieved. and the process operation variables were optimized. Crude polysaccharides (CR.PS) were obtained from A. blazei by hot water extraction filtration solvent precipitation dialysis and freeze drying. Neutral and acidic fraction of polysaccharides were separated from crude polysaccharides by ion chromatography and then high molecular weight and low molecular weight fraction were separated from neutral fraction by gel chromatography. Quantitative and qualitative analysis of each compounds were performed with FT-IR NMR spectroscopy. Based on these analysis the optimal conditions of temperatures operating time organic solvent volume for precipitation and dialysis time were determined.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.795-800
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• 2005

The optical properties of $ZnS_{y}Se_{1-x-y}:Te_x\;(x\;<\;0.08,\;y\∼0.11$) alloys grown by molecular beam epitaxy (MBE) have been investigated by photoluminescence (PL) and PL-excitation (PLE) spectroscopy. Good optical properties and high crystal quality were established with lattice match condition to GaAs substrate. At room temperature, emission in the visible spectrum region from blue to green was obtained by varying the Te content of the ZnSSe:Te alloy. The efficient blue and green emission were assigned to $Te_{1}$Tel and $Te_{n}$ (n$\geq$2) cluster bound excitons, respectively. Bright blue (462 nm) and green (535 nm) light emitting diodes (LEDs) have been developed using ZnSSe:Te system as an active layer.

• BMB Reports
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• v.38 no.2
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• pp.243-247
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• 2005

Dishevelled (Dvl) is a positive regulator of the canonical Wnt signaling pathway, which regulates the levels of $\beta$-catenin. The $\beta$-catenin oncoprotein depends upon the association of Dvl and Axin proteins through their DIX domains, and its accumulation directs the expression of specific developmental-related genes at the nucleus. Here, the $^1H$, $^{13}C$, and $^{15}N$ resonances of the human Dishevelled 2 DIX domain are assigned using heteronuclear nuclear magnetic resonance (NMR) spectroscopy. In addition, helical and extended elements are identified based on the NMR data. The results establish a structural context for characterizing the actin and phospholipid interactions and binding sites of this novel domain, and provide insights into its role in protein localization to stress fibers and cytoplasmic vesicles during Wnt signaling.

• Tribology and Lubricants
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• v.9 no.2
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• pp.16-21
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• 1993

Alkylbenzenes used as the synthetic lubricant base stocks were composed of the mixture of the various kinds of aromatic hydrocarbons. Their compositions have affected on the quality of synthetic alkylbenzene lubricants. Therefore, the rapid and accurate methods for the composit ional analysis are important. In this study, the compositions of the alkylbenzenes (Hv. LAB, FHv. LAB, Hv, BAB, DAB[HF], DAB[$AlCl_3$]) as synthetic base stocks have been investigated according to six average structural parameters(Tar, Nal, Asub, $\bar{n}$, nb, $T\alpha$) in the view of the molecular structures by $^{13}C-NMR$ spectroscopy. The experimental results of the oxidation $\varepsilon$ thermal stability tests have been related to the results of the molecular structural analysis.

• Mycobiology
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• v.48 no.1
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• pp.51-57
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• 2020

A polysaccharide (LVP) was purified from fruiting body of Lentinus velutinus by ethanol precipitation fractionation and DEAE and Sephadex G-100 column chromatography. The yield of purified polysaccharide was 0.025%. Molecular characteristics of LVP were determined by gel permeation chromatography, FT-IR spectroscopy, and thin-layer chromatography. Our results revealed that LVP is a polysaccharide composed of only glucose units, and has a molecular weight of 336 kDa. Biological activity assays indicated that LVP exhibits both cytotoxic and antioxidant activity. LVP showed specific cytotoxicity against cancer cells (HeLa and HepG2 cells), and alterations in cancer cell morphology were found after LVP treatment.