• Natural Product Sciences
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• v.11 no.1
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• pp.41-44
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• 2005

Chemical investigation of the aerial parts of Chloranthus japonicus Sieb. led to the isolation a new compound, 9-hydroxy heterogorgiolide (1) and $isofraxidin-7-O-{\beta}-D-glucopyranoside$ (2), the isolation of which is reported for the first time from this plant, along with the known components, ${\beta}-sitosterol,\;{\beta}-sitosterol-3-O-{\beta}-D-glucopyranoside$, palmitic acid and octacosanoic acid. The structures of compound 1 and 2 were determined on the basis of spectroscopic data including two dimensional NMR and high resolution MS.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.17-20
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• 1999

Facile synthetic methods of 2',5'-dideoxy-, 2',3'-dideoxy- and 3'-deoxy-1, N6-ethenoadenosine nucleosides by either an enzymatic dideoxyribosyl transfer reaction or a simple chemical reaction were proposed. The synthesis products were isolated and purified by preparative HPLC and their structures were confirmed by 1H NMR (500 MHz) and FAB-MS including high resolution mass measurement. These modified nucleoside analogs have not been reported yet. Therefore, these modified nucleoside analogs are of potential value to be studied further for biological activity such as anticancer or antiviral.

• Journal of the Korean Magnetic Resonance Society
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• v.15 no.1
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• pp.80-89
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• 2011

3D structures of STAM1 UIM-ubiquitin complex were presented to predict and analyze the interaction between UIM and ubiquitin. To generate the protein-peptide complex structure, the RosettaDock method was used with and without NMR restraints. High resolution complex structure was acquired successfully and evaluated electrostatic interaction in the protein-peptide binding with several charged residues at the binding site. From docking results, the Rosettadock method could be useful to acquire essential information of protein-protein or protein-peptide interaction with minimal biological evidences.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.150.1-150.1
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• 2011

Structure-II hydrate has been highlighted due to its higher gas storage capacity and favorable thermodynamic conditions. In this study, we introduce a new structure-II hydrate former, tert-butyl hydroperoxide (TBHP) and confirm the structural characteristics through High-Resolution Powder Diffraction (HRPD), $^{13}C$ solide-state NMR and Ramanspectroscopy. Here,we also investigated the thermodynamic stability of binary(TBHP+gaseous) clathrate hydrates. The experimental data were generated using an isochoric pressure-search method. The dissociation data for (TBHP +gaseous) clathrate hydrates are compared with the other hydrocarbon hydrate and pure gaseous hydrate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.1
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• pp.53-58
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• 2013

The active antifouling compounds coumarin and its derivatives were isolated from the cinnamon tree Cinnamomum loureiroi. The antifouling activities were determined using representative soft fouling organisms: the seaweed Ulvapertusa and diatom Navicula annexa. The chemical constituents with antifouling activities were identified as coumarin, hydroxylcoumarin, coumaric acid, and cinnamaldehyde by interpreting nuclear magnetic resonance, and high-resolution mass spectroscopy data. These compounds were isolated from 1.09 g of crude Cinnamomum sp. methanol extract, yielding approximately 18.4, 6.3, 9.8, and 14.7 mg of coumarin, hydroxylcoumarin, coumaric acid, and cinnamaldehyde, respectively. The compounds inhibited U. pertusa zoospores with $EC_{50}$ values of $0.13-0.25{\mu}g/mL$, and the diatom N. annexa with $EC_{50}$ of $0.21-0.81{\mu}g/mL$.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.31-34
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• 2000

this paper deals with the initial magnetic field decay for a large scale superconducting magnet e.g. NMR/MRI magnet. The high resolution image can not be obained during the periods of the initial field decay. It is known that all superconducting materials have the property of diamagnetism. This diamagnetism is usually explained with the concept of screening current. We assumed that the existence of the screening currebt. we assumed that the existence of the screening current makes the current distribution in the superconducting wire non-uniform. And the initial magnetic field decay is caused steady current state in the view of its pattern. The initial magnetic field decay is caused by the change of the current distribution between the energizing state and persistent current mode. in this paper the theoretical analysis for the current distributions has been introduced for each state. The experiments have been carried out to verify transport currents in order to veperiments, it small at the higher transport current.

• Natural Product Sciences
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• v.27 no.3
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• pp.183-186
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• 2021

A new acridone alkaloid, melixyloidin (1), and two known alkaloids (2-3) were isolated from Melicope xanthoxyloides (F. Muell) T.G. Hartley leaves. The structure of melixyloidin were elucidated using NMR spectra and high-resolution ESIMS data. Acridone alkaloids 1-3 were evaluated against MCF-7 and HeLa cells. 1,3,4-Trimethoxy-10-methylacridin-9-one (2) showed potent cytotoxic activity against MCF-7 cells with an IC₅₀ value of 5.31 μM.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.890-893
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• 2012

Gas hydrates are solid crystal structures formed by enclathration of gaseous guest species into 3-dimensional lattice structure of hydrogen-bonded water molecules. These compounds can be potentially used as an energy storage/transportation medium because they can hold a large amount of gas in a small volume of the solid phase. In addition, huge amount of natural gas, buried in seabeds or permafrost region in the form of the solid hydrate, is regarded as a future energy source. In this study, synthesized natural gas, whose composition is 90.0 mol% of methane, 7.0 mol% of ethane, and 3.0 mol% of propane, was used to identify formation behaviors of natural gas hydrates for the purpose of applying the gas hydrate to a storage/transportation medium of natural gas. According to the experimental results obtained by means of the solid-state NMR and high-resolution powder XRD methods, it is found that formed natural gas hydrates have crystal structure of the structure-II hydrate, and that methane occupies both small and large cages, while the others only occupy large ones. In addition, both the NMR spectroscopy and the gas chromatograph showed that there exists preferential occupation among the natural gas components during the hydrate formation. Compositional changes after the hydrate formation revealed that the preferential occupation is in order of propane, ethane, and methane (propane is the most preferential guest species when forming natural gas hydrates).

• Mycobiology
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• v.49 no.4
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• pp.434-437
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• 2021

In our ongoing search for new secondary metabolites from fungi, a basidiomycete fungus Irpex consors was selected for mycochemical investigation, and three new zwitterionic alkaloids (1-3) and five known compounds (4-8) were isolated from the culture broth (16 l) of I. consors. The culture filtrate was fractionated by a series of column chromatography including Diaion HP-20, silica gel, and Sephadex LH-20, Sep-Pak C₁₈ cartridge, medium pressure liquid chromatography (MPLC), and high pressure liquid chromatography (HPLC) to yield eight compounds (1-8). The structures of the isolated compounds were elucidated by the interpretation of nuclear magnetic resonance (NMR) spectra and high-resolution mass spectrometry (HR-MS). Their antioxidant and antibacterial activities were examined. The zwitterionic structures of three new sesquiterpene alkaloids (1-3) were determined together with five known compounds identified as stereumamide E (4), stereumamide G (5), stereumamide H (6), stereumamide D (7), and sterostrein H (8). This is the first report of the zwitterionic alkaloids in the culture broth of I. consors. Three new zwitterionic alkaloids were named as consoramides A-C (1-3).

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.4
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• pp.91-100
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• 2018

Benzisothiazolinone (BIT) is the preservative that is widely used in industrial and household products. In this study, zebrafish (Danio rerio) was exposed to BIT at different concentrations (control, 0.5 g/L, 1.0 g/L and 2.0 g/L) for 72 hours. The techniques of nuclear magnetic resonance (NMR) spectroscopy were applied to analyze the effects of BIT on zebrafish. The advantages of NMR are the minimal sample preparation and high reproducibility of experimental results. With the multivariate statistical analysis, dimethylamine, N-acetylaspartate, glycine and histidine were identified as an important metabolite in differentiating between the control and BIT-exposed group. This study will improve the understanding the metabolite changes in the zebrafish in response to BIT exposure.