• 한국미생물·생명공학회지
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• 제25권6호
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• pp.586-591
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• 1997

In the course of screening for the tipA promoter-inducing substances, we isolated an active compound, sulfomycin Ia, from the mycelium of a microorganism designated 50634. The producing organism was identified as Streptomyces sp. on the basis of taxonomic studies. Sulfomycin Ia was purified from mycelial extract by silica gel column chromatography, LH-20 column chromatography, silica gel TLC, and preparative HPLC. The molecular weight of sulfomycin Ia was determined to be m/z 1129 (M+Na)$^{+}$ by FAB mass measurement and $^{1}$H NMR spectroscopic analysis. The structure was assigned as a derivative of sulfomycin I with thiazole, methyloxazole, oxazole, and pyridine rings by $^{1}$H NMR spectral data.

• Journal of Applied Biological Chemistry
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• 제61권1호
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• pp.79-82
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• 2018

An ${\alpha}-{\text\tiny{D}}-glucoside$ of sesterterpene, 11-epiterpestacin, was isolated from the culture of a filamentous fungus Bipolaris sorokiniana NSDR-011. The structure was elucidated by chemical studies and spectroscopic methods including NMR and ESI-MS. 11-ETG (1) named arbitrarily did not inhibit the root growth of Italian ryegrass seedlings even at the level of 200 ppm, while its aglycone 11-ET (2) completely inhibited root growth at level of 100 ppm.

• 분석과학
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• 제18권1호
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• pp.1-4
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• 2005

반응 속도를 조절하기 위하여 유기 첨가제인 아세트산을 사용해 치환된 티타늄 이소프로폭사이드를 합성한 뒤 가수분해 시킨 실리콘(IV)에톡사이드와 반응시켜 $TiO_2-SiO_2$ 분말을 얻었다. 반응 과정 동안의 구조 변화와 특징을 NMR과 FT-IR을 통해서 살펴보았다. 열처리 과정을 거친 분말의 FT-IR 결과로부터 상 분리를 관찰하였다.

• Journal of Astronomy and Space Sciences
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• 제29권1호
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• pp.63-67
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• 2012

Observations with milliarsecond resolution using the Navy Optical Interferometer have been obtained for a number of stellar systems which include high-mass binaries, eclipsing binaries, and radio stars. These observations also reveal the previously unseen companions in single-lined spectroscopic binaries via directly measured flux ratios. We will present examples of published and ongoing research efforts of these systems to illustrate how an optical interferometer contributes to our knowledge of stars, their environment, and companions. These studies include a conclusive revealing of the previously unseen companion in the single-lined binary ${\Phi}$ Herculis, the direct determination of orbital parameters in the wide and close orbits of Algol, and revealing the orbit of ${\beta}$ Lyrae with spatially resolved images of the $H{\alpha}$ emission.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.209-213
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• 1995

During the screening of inhibitors of melanin biosynthesis from microbial secondary metabolites, a fungal strain MR-93 which was capable of producing high level of an inhibitor was selected from plant leaf. Based on taxonomic studies, the fungus could be classified as a strain of Trichoderma sp.. The active compound (MR-93D) was purified from the culture broth by Diaion HP-20 column chromatography, ethylacetate extraction, Sephadex LH-20 column chromatography and HPLC. The inhibitor was identified as 4-hydroxy-8-isocyano-l-oxaspiro[4-4]cyclonon-8-en-2- one by spectroscopic methods of UV, $^{1}$H-NMR, ESIMS and IR. MR-93D showed a strong tyrosinase inhibitory activity with 0.03 $\mu$g/m of IC$_{50}$ value. It also inhibited melanin biosynthesis with 35 mm inhibition zone at 30 $\mu$g/paper disc in Streptomyces bikiniensis, a bacterium used as an indicator organism in this work.

• 한국약용작물학회지
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• 제3권2호
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• pp.91-95
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• 1995

국내(國內)에서 생산(生産)된 백화사설초(百花蛇舌草) Oldenlandia diffusa(WiIId.) Roxb. 의 전초로 부터 얻은 MeOH extract를 $CHCl_3, EtOAc$ 및 BuOH로 분획하여 얻은 fraction으로 부터 column chromatography를 실시하여 3종의 화합물을 분리하였다. 이들의 이화학적(理化學的) 및 분광학적(分光學的) data를 종합하여 화합물 I의 화학구조는 ${\beta}-sitosterol$에 소양(小量)의 stigmasterol이 함유된 sterol이며, 화합물 II는 ursolic acid이고, 화합물 III은 ${\beta}-sitostero\;3-0-{\beta}-D-glucoside$임을 밝혔다. 이 식물은 다양한 생리활성(生理活性)이 보고(報告)된 ursolic acid의 중요한 자원식물(資源植物)이 될 수 있음을 본실험을 통하여 밝혔으며 문헌(文獻)에 보고(報告)된 oleanolic acid는 함유(含有)되어 있지 않음을 알았다.

• Journal of Radiation Protection and Research
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• 제45권1호
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• pp.11-15
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• 2020

Background: There have been various studies to investigate the mechanisms of DNA damage from low-energy electrons. To understand the mechanism of these strand breaks, it is necessary to investigate the dissociation mechanism of the DNA constituents, that is, bases, sugars, and phosphates. Materials and Methods: We studied the dissociation of thymine base upon interaction with low-energy electrons. For this experiment, thymine powder was pressed onto the indium base and irradiated by 5 eV electrons. Results and Discussion: Non-irradiated and irradiated thymine samples were compared and analyzed using the X-ray photoelectron spectroscopic technique to analyze the dissociation patterns of the molecular bonds after low-energy electron irradiation of thymine. Conclusion: With 5 eV electron irradiation, C-C and N-C = O bonds are the primary dissociations that occur in thymine molecules.

• 천문학회보
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• 제39권2호
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• pp.75.1-75.1
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• 2014

We present the result of a long-slit spectroscopic study of DG Tau, which is known to emanate parsec-scale outflows. To study the kinematics and physical properties of the jet, we obtained the optical emission lines of $H{\alpha}$, [OI], [NII], and [SII] from HH 158 and HH 702 using the long-slit spectrograph at Bohyunsan Optical Astronomical Observatory. HH 158 shows the peak radial velocity in a range of ~ - 270 to - 30 km s-1. HH 702, located at 11' away from DG Tau shows the velocity of ~ - 80 km s-1. The proper motion velocities of detected knots are estimated through the comparisons with the locations of those knots in the previous studies. We also examine the variations of physical parameters depending on the velocity distribution and the distance from the source using line ratio maps derived from obtained forbidden emission lines.

• 한국세라믹학회지
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• 제52권6호
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• pp.502-507
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• 2015

We examined the photo catalytic activity and catalytic recyclability of CdSe/graphene nanocomposites fabricated via modified hydrothermal technique. The prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Raman spectroscopic analysis, and X-ray photoelectron spectroscopy (XPS). The photocatalytic behavior was investigated through decomposition of RBB as a standard dye under visible light radiation. Our results indicate that there is significant potential for graphene based semiconductor hybrids materials to be used as photocatalysts under visible light irradiation for the degradation of organic dyes from industry effluents.

• BMB Reports
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• 제32권1호
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• pp.76-81
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• 1999

Dihydrolipoamide dehydrogenase (E3) belongs to the protein family of pyridine nucleotide-disulfide oxidoreductases, including glutathione reductase (GR). The two subunits of human GR are covalently linked by an intersubunit disulfide bond between the pair of the Cys-90 residues. The corresponding residue (Ser-79) in human E3 was substituted to Cys using site-directed mutagenesis. The mutant was expressed in Escherichia coli and highly purified using an affinity column. About 40% of the mutants formed a spontaneous intersubunit disulfide bond linkage. This result implies that Ser-79 and possibly surrounding residues constitute one of the several intersubunit contact regions in human E3. It provides another good piece of evidence for the predicted high degree of the structural homology between human E3 and GR. Spectroscopic studies indicate conformational changes in the mutant.