• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.268-268
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• 1994

포자의 전자현미경사진과 mycelium의 광학현미경사진을 찍어 strain V-8 균주의 형태학적인 특성을 조사하였을 때 방선균 계열인 streptomyces로 확인되었다. 이 균주의 배양액은 노란색을 띠고 있고 이 노란색은 430 nm에서 특징적인 흡광을 보였다. 이 물질은 유기 용매로 추출되었다. 이 물질의 자외선 흡광스펙트럼의 특징을 기존에 보고된 화합물과 비교하여 이 물질이 actinomycin계열에 속함을 발견하였다. 이 물질의 FAB mass spectrum에서 각 분획들의 주성분들의 분자의 질량 + H 이온이 1290과 1292에서 각각 관찰되었다. 이 화합물들은 분자량이 1258인 actinomycin D와는 상이한 구조를 소유하고 있는 것으로 확인되었다. 각 분획 성분들의 proton 및 carbon HIR spectra를 얻어 기존에 알려진 화합물의 자료와 비교하였을 때 actinomycin계열에 속하는 신물질로 생각되었다. 지금까지 actinomycin 계열의 항생물질이 adenosine deaminase의 효소 활성을 저해한다는 사실은 보고된바 없다. 본 연구자는 분리한 2개의 화합물에 대하여 구조 연구를 계속하고 있다.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.159-165
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• 1999

Pseudomonas aeruginosa JRT-4 strain was used as a biosurfactant-producing microorganism in this study. It was one of the microorganisms isolated from the sewage sludge, the main and branch streams of Han river. The surface tension of the culture broth of P. aeruginosa JRT-4 decreased to 30mN/m. The crude biosurfactant was obtained from the culture broth by acid precipitation, solvent extraction, evaporation, and freeze drying. The CMC value of the crude biosurfactant was 0.006%(w/v). From analysis of the chemical structure of biosurfactant, it was determined as rhamnolipid 1 and 3 structures by FAB mass spectrometer. In the washing test for artificially contaminated textiles, the biosurfactant showed better bleachness than the two chemically synthesized surfactant, LAS and SLES. Finally, the biodegradation and ecotoxidolorical tests showed that the biosurfactant was readily biodegradable in the environment and a mild material for microorganisms and green algae.

• IMMUNE NETWORK
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• v.10 no.2
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• pp.35-45
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• 2010

Background: Expression of recombinant antibodies and their derivatives fused with other functional molecules such as alkaline phosphatase in Escherichia coli is important in the development of molecular diagnostic reagents for biomedical research. Methods: We investigated the possibility of applying a well-known Fos-Jun zipper to dimerize $V_H$ and $V_L$ fragments originated from the Fab clone (SP 112) that recognizes pyruvate dehydrogenase complex-E2 (PDC-E2), and demonstrated that the functional zipFv-112 and its alkaline phosphatase fusion molecules (zipFv-AP) can be produced in the cytoplasm of Origami(DE3) trxB gor mutant E. coli strain. Results: The zipFv-AP fusion molecules exhibited higher antigen-binding signals than the zipFv up to a 10-fold under the same experimental conditions. However, conformation of the zipFv-AP seemed to be influenced by the location of an AP domain at the C-terminus of $V_H$ or $V_L$ domain [zipFv-112(H-AP) or zipFv-112(L-AP)], and inclusion of an AraC DNA binding domain at the C-terminus of VH of the zipFv-112(L-AP), termed zipFv-112(H-AD/L-AP), was also beneficial. Cytoplasmic co-expression of disulfide-binding isomerase C (DsbC) helped proper folding of the zipFv-112(H-AD/L-AP) but not significantly. Conclusion: We believe that our zipFv constructs may serve as an excellent antibody format bi-functional antibody fragments that can be produced stably in the cytoplasm of E. coli.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.105-113
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• 2009

The freezed Mulberry (10 kg) was extracted with 80% EtOH, concentrated, and fractionated with a series of n-hexane, ethyl acetate, and water on a separatory funnel. A portion of ethyl acetate soluble (22 g) was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol as eluents. The isolated compounds were identified by cellulose TLC, $^1H-$,$^{13}C$-NMR, FAB, and EI-MS. Quercetin-3-O-${\beta}$-D-glucopyranoside (Compound I), protocatechuic acid (Compound II), p-hydroxybenzoic acid (Compound III) were isolated from the ethyl acetate soluble fraction. In antioxidative activities of the fractionated extractives using DPPH radical scavenging test, EtOAc and water soluble fractions indicated better than BHT as contro and in in vitro tests using MTT assay, there was no cytotoxicity. Also, tyrosinase inhibition and anticancer activities were not so good, but there may be a potential as a cosmetic raw material because the cell extension effect was excellent.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.201-206
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• 2019

This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide ($Ga_2O_3$) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating ${\beta}-Ga_2O_3$ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of $10{\times}15mm^2$. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length ($L_g$) of $2{\mu}m$ and a gate-drain spacing ($L_{gd}$) of $5{\mu}m$. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for $V_{gs}<-6V$, and the three-terminal off-state breakdown voltage was over 482 V in a $L_{gd}=5{\mu}m$ device measured in Fluorinert ambient at $V_{gs}=-10V$. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately $5.3{\times}10^5$. These device characteristics indicate the promising potential of $Ga_2O_3$-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.977-982
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• 2004

The reaction of $cis-[Cr([14]-decane)(OH_2)_2]^+$ ([14]-decane = rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-teraazacyclotetradecane) with auxiliary ligands {$L_a$ = benzoate(bz) or chlorobenzoate(cbz)} leads to a new compound $[Cr([14]-decane)(bz)_2]ClO_4$ or $[Cr([14]-decane)(cbz)_2]ClO_4$. These complexes have been characterized by a combination of elemental analysis, conductivity, IR and Vis spectroscopy, mass spectrometry, and X-ray crystallography. The crystal structure of $[Cr([14]-decane)(cbz)_2]^+$ was determined. The complex shows a distorted octahedral coordination environment with the macrocycle adopting a folded cis-V conformation. The angle $N_{axial}-Cr-N_{axial}$ deviates by $14.5^{\circ}$ from the ideal value of $180^{\circ}$for a perfect octahedron. The bond angle cis-O-Cr-O between the Cr(III) ion and the two carboxylate oxygen atoms of the monodentate p-chlorobenzoate ligands is close to 90$^{\circ}$. The FAB mass spectra of the $cis-[Cr([14]-decane)(La)_2]ClO_4$ display peaks due to the molecular ions $[Cr([14]-decane)(bz)_2-H]^\;,\;[Cr([14]-decane)(cbz)_2-2H]^$ at m/z 578, 646, respectively.

• Journal of the Korean institute of surface engineering
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• v.41 no.1
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• pp.38-42
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• 2008

316L stainless steel welding tube was electrolytically polished and the inner surface characteristics of the tube were tested. Electro-polishing variables such as current, voltage, concentration of electrolyte and electropolishing time were changed to seek for optimum condition. These makes a optimum conditions for the electro-polishing as 4000 A, 9 V, 1.7 specific gravity of electrolyte, and 30 minute of electro-polishing time. It makes the surface roughness as Ra < $0.25{\mu}m$. XPS test resulted as the ratio of CrO/FeO equals or more to 3/1. AES test resulted as the thickness of CrO film of $38{\AA}$. DTA test resulted as the tube did not react with $N_2,\;H_2\;and\;O_2$ gas below 1073K. As summarize above results, the electro- polished 316L stainless steel welding tube satisfied the conditions to apply as a pipeline for semi- conductor production facility and clean room.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.722-726
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• 1993

Organotin(IV) complexes of ylidenemalonates $(R_xSn)_{x-1}(O_2C)_2C=C(SR')_2\;(R=n-C_4H_9,\;C_6H_5,\;cyclo-C_6H_{11},\;CH_3OOCCH_2CH_2;\;x=2,3;\;R'=CH_3,\;R_2'=-CHCH-,\;-CH_2CH_{2^-})$ have been synthesized and characterized by means of various spectroscopic methods. The X-ray crystal structure of $(Ph_3Sn)_2(O_2C)_2C=C(SCH_3)_2$ has been determined (Pi; a= 9.704(2) ${\AA}$, b= 14.412(1) ${\AA}$, c= 14.760(3) ${\AA}$, ${alpha}$=74.26(1)$^{\circ}$, ${beta}$=99.38(l)$^{\circ}$, ${\gamma}$=79.09(1)$^{\circ}$, $V= 1950.7(7){\AA}^3$) and refined to R= 0.045. The crystal structure discloses a discrete molecule with bidentate-like carboxylate ligand. For diorganotin analogues, the structures are discussed in terms of IR, $^1H-NMR,\;^{13}C-NMR$, and FAB mass spectrometry. The mass spectrum indicates that the diorganotin complexes of ylidenemalonates are dimeric.

• Animal cells and systems
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• v.15 no.4
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• pp.259-267
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• 2011

This study was undertaken to produce a $F_{ab}$ fragment of a human monoclonal antibody reactive to oxidized and carbamylated low-density lipoprotein (oxLDL and cLDL) using phage display technology. An analysis of DNA sequences of this $F_{ab}$, termed plaque 15,16-46 $F_{ab}$, revealed that the rearranged $V_H$ was highly mutated. Complementarity-determining regions of the $V_H$ showed a very high R/S ratio and contained many positively charged amino acids. In direct binding and competitive ELISA, the $F_{ab}$ reacted strongly with both MDA-LDL and Cu-oxLDL forms of oxLDL, and also showed high affinity for cLDL. Immunofluorescence and immunohistochemical analyses showed that this $F_{ab}$ positively stained atherosclerotic aortic plaques in $ApoE^{-/-}$ mice as well as those in patients with atherosclerosis. The $F_{ab}$ also showed positive staining in placental decidua from patients with preeclampsia. It is suggested that the plaque 15,16-46 $F_{ab}$ against oxLDL and cLDL might possibly be applicable for developing a diagnostic reagent for both human and rodent animal research to detect and characterize atherosclerotic disease progression in atherosclerotic lesions as well as exploring the pathogenesis of atherogenic diseases such as preeclampsia.

• YAKHAK HOEJI
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• v.52 no.4
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• pp.241-251
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• 2008

In this study, isolation of antioxidative compounds was performed for development of anti-oxidizing agent. $CHCl_{3}$, $H_{2}O$, 30%, 60% MeOH, MeOH fractions were examined antioxidative activity by DPPH method, TBARS assay, and SOD like activity. It was revealed that 30%, 60% MeOH fractions had significant antioxidative activity. From 30%, 60% MeOH fraction, nine compounds were isolated and elucidated kaempferol $3-O-{\alpha}-L-rhamnopyranosyl$ $(1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (1), quercetin $7-O-{\beta}-D-glucopyranoside$ (II), quercetin $3-O-{\alpha}-L-rhamnopyranosyl$ $(1{\rightarrow}6)$ ${\beta}-D-glucopyranoside(rutin)$ (III), 6-hydroxykaempferol $3-O-{\beta}-D-glucopyranoside$ (lV), kaempferol $3-O-{\beta}-D-glucopyranosyl$ $(1{\rightarrow}2)$ ${\beta}-D-glucopyranoside$ (V), kaempferol $3-O-{\beta}-D-glucopyranoside$ (VI), luteolin (VII), quercetin $3-O-{\beta}-D-glucopyranoside$ (VIII), apigenin $7-O-{\beta}-D-glucuronopyranoside$ (IX) through physicochemical data and spectroscopic methods (Negative FAB-MS, $^1H-NMR$, $^{13}C-NMR$). Entirely, all compounds had similar antioxidative activity, but more OH group had more antioxidative activity.