• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.41-48
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• 2002

The barks of oak trees (Quercus acutissima and Quercus variabilis) were collected, extracted with acetone-$H_2O$ (7:3, v/v), fractionated with hexane, $CH^2C1^2$ EtOAc and -$H_2O$, then freeze dried to give dark brown powder. The EtOAc soluble mixtures of the trees were chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The structures of isolated compounds were characterized by $^1H$, $^13C$ and 2D-NMR spectroscopy and molecular weights were determined by FAB-MS spectra. The isolated compounds from Quercus acutissima were (+)-catechin, (+)-gallocatechin, gallic acid and taxifolin-3-O-$\beta$-D-glucopyranoside and the compounds from Quercus variahilis (+)-catechin, caffeic acid and taxifolin-3-O-$\beta$-D-glucopyranoside.

• BMB Reports
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• v.44 no.4
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• pp.244-249
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• 2011

The quality of a phage-displayed antibody library deteriorates with clonal variations, which are caused by differentially expressed Escherichia coli antibody genes. Using the human Fab SP114 against the pyruvate dehydrogenase complex-E2 (PDCE2), we created four E. coli TOP10F' clones with a pCMTG phagemid encoding Fab-pIII (pCMTG-Fab), Fd ($V_H+C_{H1}$)-pIII (pCMTG-Fd), or light chain (L) (pCMTG-L), or the vector only (pCMTG-${\Delta}Fab$) to investigate the effect of clonal variations in a defined manner. Compared to the others, the E. coli clone with pCMTG-Fab was growth retarded in liquid culture, but efficiently produced phage progenies by Ex12 helper phage superinfection. Our results suggest that an antibody library must be cultured for a short duration before helper phage superinfection, and that the Ex12 helper phage helped to alleviate the detrimental effect of clonal variation, at least in part, by preferentially increasing functional phage antibodies during phage amplification.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.76-82
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• 2006

The dried ground needles (2.0 kg) of Chamaecyparis pisifera (Sieb. et Zucc.) Endlicher were extracted with acetone-$H_2O$ (7:3, v/v), concentrated, and fractionated with a series of n-hexane, methylene chloride, ethyl acetate and water on a separation funnel. Each fraction was freeze dried, then a portion of ethyl acetate soluble powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-n-hexane mixture as eluents. The isolated compounds were identified by cellulose TLC, $^1H$-, $^{13}C$-NMR, COSY, HETCOR, FAB and EI-MS. (+)-catechin, taxifolin-3-O-${\beta}$-D-xylopyrano-side, quercetin-3-O-${\alpha}$-L-rhamnopyranoside were isolated from the ethyl acetate soluble fraction of Chamaecypairs pisifera needle. Antioxidative tests on the isolated compounds indicated that all of the compounds showed similar values to ${\alpha}$-tocopherol and BHT as controls.

• Journal of Forest and Environmental Science
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• v.18 no.1
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• pp.53-60
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• 2001

2kg of the dried leaves of chamaecyparis obtusa Endlicher were ground, extracted with acetone-$H_2O$(7:3, v/v), concentrated, and fractionated with a series of hexane, $CH_2Cl_2$, EtOAc and water on a separatory funnel. Each fraction was freeze dried to give dark-brown powder and a EtOAc soluble portion of the powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. Spectrometric analyses such as NMR and FAB-MS including TLC were performed to characterize the structures of the isolated compounds. The leaves of chamaecyparis obtusa Endlicher contained a large amount of taxifolin-3-O-${\beta}$-D-xylopyranoside and (+)-catechin in addition to a small amount of quercetin-3-O-${\alpha}$-L-rhamnopyranoside.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.56-64
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• 2002

2kg of the dried leaves of Thuja orientalis Linnaeus were ground, extracted with acetone-$H_2O$(7:3, v/v), concentrated, and fractionated with a series of hexane, $CH_2C1_2$ EtOAc and water on a separators funnel. Each fraction was freeze dried to give dark-brown powder and a EtOAc soluble portion. of the powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. Spectrometric analyses such as NMR and FAB-MS including TLC were performed to characterize the structures of isolated compounds. The leave of Thuja orientalis Linnaeus contained a large amount of flavononol derivatives such as quercetin-3-O-$\alpha$-L-rhamnopyranoside and myricetin-3-O-$\alpha$-L-rhamnopyranoside in addition to a small amount of flavan compounds such as (+)-catechin and (+)-gallocatechin. The antioxidative activities of each fractions and isolated compounds were done by DPPH radical scavenging test, and all of them were indicated strong antioxidative activities.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.59-66
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• 2004

The dried neeldes(1.5 kg) of Juniperus rigida were ground, extracted with acetone-H₂O(7:3, v/v), concentrated, and fractionated with a series of hexane, CH₂Cl₂, EtOAc and water on a separatory funnel. Each fraction was freeze dried to give dark-brown powder and EtOAc and water soluble fractions were chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluent. Spectrometric analysis such as NMR and FAB or EI-MS including TLC were performed to characterize the structures of the isolated compounds. The needles of Juniperus rigida contained a large amount of (+)-catechin, quercetin-3-O-α-L-rhamnopyranoside and isoconiferin, in addition to a small amount of umbelliferone and quercetin-3-O-β-D-rutinoside. The antioxidative activities of each fraction and isolated compounds were tested by DPPH radical scavenging method, and EtOAc soluble fraction, (+)-catechin and quercetin-3-O-α-L-rhamnopyranoside were effective.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.217-227
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• 2012

Syntheses of some novel oxomolybdenum(V) and dioxomolybdenum(VI) complexes with an azo dye methoxyphenolazoantipyrine (HL) derived from 4-aminoantipyrine and 2-methoxyphenol are reported. The complexes have been characterized by elemental analyses, molar conductance, magnetic susceptibility data, IR, UV-Vis, $^1H$ NMR, EPR and FAB mass spectral studies. The physicochemical studies and spectral data indicate that HL acts as a bidentate chelating ligand. The complexes have the general formulae [$MoO(HL)XCl_2$] and [$MoO_2(HL)XCl$],where X=Cl, NCS or $NO_3$. All the complexes are found to have distorted octahedral geometry. Structural and morphological characterization of the complexes [$MoO(HL)Cl_3$](1) and [$MoO_2(HL)Cl_2$](4) before and after gamma ray irradiation,was performed by X-ray diffraction and scanning electron microscopy( SEM).The ligand and the complexes were screened for their possible antimicrobial activities.

• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.288-292
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• 2013

In this paper, a carbon implant is investigated in detail from the perspectives of performance advantages and side effects for the thick n-type metal-oxide-semiconductor field-effect transistor (n-MOSFET). Threshold voltage ($V_{th}$) adjustment using a carbon implant significantly improves the $V_{th}$ mismatch performance in a thick (3.3-V) n-MOS transistor. It has been reported that a bad mismatch occurs particularly in the case of 0.11-${\mu}m$ $V_{th}$ node technology. This paper investigates a carbon implant process as a promising candidate for the optimal $V_{th}$ roll-off curve. The carbon implant makes the $V_{th}$ roll-off curve perfectly flat, which is explained in detail. Further, the mechanism of hot carrier injection lifetime degradation by the carbon implant is investigated, and new process integration involving the addition of a nitrogen implant in the lightly doped drain process is offered as its solution. This paper presents the critical side effects, such as Isub increases and device performance shifts caused by the carbon implant and suggests an efficient method to avoid these issues.

• YAKHAK HOEJI
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• v.40 no.4
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• pp.422-427
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• 1996

The anti-Ex-A IgG was specifically labeled with stable isotopes, DL-His-2,4-$d_2$, L-Phe-$d_5$, L-Trp-$d_5$, L-Tyr-2,6-$d_2$ and L-[1-$^{13}C$]Trp, by growing hybridoma cell in serum-free medium. By use of NMR spectroscopy with selectively labeled Fab fragment, we applied a paratope mapping on antigen-antibody complex. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C$-$^{15}N$ double labeling method in order to assign the Trp resonances. Photo CIDNP was also applied to investigate the antigen-binding site(s) on the surface residues of antibody. We found that Trp 36, which is located at the $V_H$ domain, is an important residue to bind to Ex-A, however, two Tyr on the surface of anti-Ex-A IgG plays no crucial role to bind to antigen. On the basis of these results, we demonstrate that stable isotope-aided NMR strategy can be extended to molecular structural analyses of the complex of an Fab fragment and a protein antigen.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.73-83
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• 2006

The dried needles (1.5 kg) of Abies koreana and Abies holophylla were ground, extracted with acetone-$H_2O$ (7:3, v/v), concentrated, and fractionated with a series of hexane, methylene chloride, ethyl acetate and water on a separatory funnel. Each fraction was freeze dried, then a portion of ethyl acetate soluble powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The isolated compounds were identified by cellulose TLC, $^1H$, $^{13}C-NMR$, COSY, HETCOR, FAB and EI-MS. The needles of Abies koreana and Abies holophylla contained a large amount of aromadendrin-7-O-${\beta}$-D-glucopyranoside (compound III), polydatin (compound VI), (-)-rhododendrol-2-O-${\beta}$-D-glucopyranoside (compound VII), in addition to a small amount of (+)-catechin (compound I), kaempferol-3-O-${\beta}$-D-glucopyranoside (compound IV), myricetin-3-O-${\beta}$-D-glucopyranoside (compound V), naringenin-7-O-${\beta}$-D-glucopyranoside (compound II). DPPH analysis was also tested to investigate the antioxidative effects on the isolated compounds and (+)-catechin and polydatin were effective.