• Journal of the Korean Magnetic Resonance Society
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• v.22 no.2
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• pp.26-33
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• 2018

Xanthium sibiricum is used as a traditional folk medicine for the treatment of cancer, fever, headache, nasal sinusitis, and skin pruritus. This study aimed to identify components from Xanthium sibiricum extracts using an SPE-800MHz NMR-MS hyphenated system. The simultaneous acquisition of MS and NMR spectra from the same chromatographic peaks significantly increases the depth of information acquired for the compound and allows the elucidation of structures that would not be possible using MS or NMR data alone. LC -NMR analysis was conducted using a HPLC separation system coupled to 800 MHz spectrometer equipped with a cryoprobe, and a SPE unit was used to automatically trap chromatographic peaks using a HPLC pump. LC-MS analysis was conducted with a Q-TOF MS instrument using ESI ionization in the negative ion mode. Using the hyphenated analysis, several secondary metabolites were identified, such as 3',5'-O-dicaffeoylquinic acid, 1',5'-O-dicaffeoyl- quinic acid, and ethyl caffeate. These results demonstrate that the SPE-800MHz NMR-MS hyphenated system can be used to identify metabolites within natural products that have complex mixtures.

• Analytical Science and Technology
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• v.23 no.1
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• pp.97-101
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• 2010

(R)-N-3,5-dinitrobenzoyl (DNB) phenylglycinol derived chiral selector was used as a HPLC chiral stationary phase (CSP) for the resolution of racemic N-acylnaphthylalkylamines. In this study, determination of optical purity was performed by both chiral chromatography and NMR spectroscopy by using the (R)-phenylglycinol derived chiral selector. The data of accuracy and precision of each optical purity value are calculated from the results of NMR and HPLC experiments by comparing with true value. Average error of the NMR method was +2.2% with average RSD of 4.54%, while that of HPLC method was -3.5% with average RSD of 3.23%.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.539-542
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• 2001

$^1H$-NMR spectroscopy was used to detect apoptosis in HL-60 cells in vitro. The relationship between cell apoptosis and NMR data was validated by the flow cytometry assay. To evaluate the NMR apoptosis results, the ratio of methylene and methyl groups caused by lipids was used. In addition, an identical analysis was applied to HepG2 cells. Detection of apoptotic cell death by NMR spectroscopy was oserved.

• Archives of Pharmacal Research
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• v.17 no.6
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• pp.393-397
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• 1994

Rhomobifoline and 5,6-dehydrolupanine were isolated for the frist time from the leaves and stems of A. foetida L. indigenous to Saudil Arabia. In addition, five other alkaloids, previously identified in A, foetidia L., namely N-methylcytisine, sparteine, anagyrine, lupanine and cytisine, were isolated. The isolated alkaloids were characterized by UV, $^1-NMR,{\;}^{13}H-NMR,{\;}^{13}C-NMR{\;}and{\;}Mass{\;}spectral{\;}data.{\;}^{13}C-NMR$ data of rhombifoline and 5,6-dehydroupanine are reported for the first time.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1559-1562
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• 2009

The influence of hot pressing on the pore structures of Nafion membranes was investigated by observing the Nafion before and after hot pressing with $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The freezing point depression and chemical shift data of water in the Nafion indicated the presence of two different pore size ranges in Nafion. Hot pressing mainly reduced the sizes and number of the big pores. The reduction of water uptake and proton conductivity after hot pressing was explained by this variation of pore size and number. We demonstrated the potential application of chemical shift data and NMR cryoporometry experiments to measure the relative pore sizes, on a nano scale, and numbers.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.201-205
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• 1997

A very high content (at least 0.23%) of ergosterol peroxide was isolated from Naematoloma fasciculare Karst. Not only ergosterol peroxide but also ergosterol showed very strong anticomplementary activity on the classical pathway, the $IC_{50}$ values being $5.0 {\mu}M$ and $1.0 {\mu}M$, respectively. The $ ^{1}H $and $^{13}C$ NMR data of ergosterol peroxide were revised and completely assigned by DEPT, $^{1}H-^{1}H$ COSY, HMQC and HMBC correlations.

• Bulletin of the Korean Chemical Society
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• v.22 no.5
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• pp.507-513
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• 2001

Histones, nuclear proteins that interact with DNA to form nucleosomes, are essential for both the regulation of transcription and the packaging of DNA within chromosomes. The N-terminal domain of histone H4 which contains four acetylation sites at lysines, may play a separate role in chromatin structure from the remainder of the H4 chain. NMR data suggest that H4NTP peptide does have relating disordered structure at physiological pH, however, it has a defined structure at lower pH conditions. The solution structure calculated from NMR data shows a well structured region comprising residues of Val21-Asp24. In addition, our results suggest that the H4NTP prefers an extended backbone conformation at acetylation sites, however, it (especially Lys 12 ) became more defined structures after acetylation for its optimum function.

• Neonatal Medicine
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• v.18 no.2
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• pp.182-188
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• 2011

Purpose: Recently in Korea, there have been significant improvements in neonatal mortality rate (NMR) and infant mortality rate (IMR). This study aimed to investigate the proportion of the NMR among IMR, with the goal of discerning the influence of improved NMR on the reduction of IMR in the last 5 years in Korea. Methods: All data were from Statistics Korea. Changes in the NMR percentage among IMR and the percentage of the death by the distribution of the birth weight and gestational were investigated. Results: The total birth rate decreased, but the total number of preterm and low birth weight infants increased. These was a large decrease in NMR and IMR. The proportion of NMR among INR exceeded 50%. Early NMR was higher than late NMR. Among the total infant death, the mortality of preterm and low birth weight infants was high. Conclusion: Between 2005 and 2009, the total birth has declined in Korea, but the frequency of low birth weight infants is trending upward. The improvements in NMR and IMR, and the downtrend of the NMR percentage in IMR, are encouraging. It seems that the continued decrease of mortality of preterm and LBWI is required for better improvements NMR and IMR in Korea. This result is expected to be used for the basic data to improve the management of the newborns in Korea.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3644-3649
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• 2011

Multinuclear solid-state nuclear magnetic resonance (NMR) experiments were performed to investigate the local structure changes of nanoporous silica during hydrothermal treatment and surface modification with 3-aminopropyltriethoxysilane (3-APTES). The nanoporous silica was prepared by sol-gel polymerization using inexpensive sodium silicate as a silica precursor. Using $^1H$ magic angle spinning (MAS) NMR spectra, the hydroxyl groups, which play an important role in surface reactions, were probed. Various silicon sites such as $Q^2$, $Q^3$, $Q^4$, $T^2$, and $T^3$ were identified with $^{29}Si$ cross polarization (CP) MAS NMR spectra and quantified with $^{29}Si$ MAS NMR spectra. The results indicated that about 25% of the silica surface was modified. $^1H$ and $^{29}Si$ NMR data proved that the hydrothermal treatment induced dehydration and dehyroxylation. The $^{13}C$ CP MAS and $^1H$ MAS NMR spectra of 3-APTES attached on the surface of nanoporous silica revealed that the amines of the 3-aminopropyl groups were in the chemical state of ${NH_3}^+$ rather than $NH_2$.

• Applied Biological Chemistry
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• v.37 no.2
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• pp.100-104
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• 1994

From the 48 hour-cultured mycelial broth of Phellinus linteus, six compounds were isolated by means of ethyl acetate extraction, silica gel column chromatography and preparative thin layer chromatography, consecutively. Compound 1 was identified as a succinic acid by the comparison of its spectral data with authentic sample. Compounds 2 and 3 were identified as p-hydroxyphenyl acetic acid methyl ester and p-hydroxybenzaldehyde by spectroscopic studies, respectively. NMR and MS studies of compound 6 revealed that it was 2,5-dihydroxymethyl furan. Compound 4, which showed similar NMR absorptions and MS fragmentation pattern with those of compound 6 was identified as 2-hydroxymethyl-5-methoxymethylfuran. These structures were verified by the spectral data of the acetate derivatives of the compounds. Compound 5 was supposed to be a N-acetyltyramine from its $^1H-NMR$ and EI-MS data, and its structure was confirmed by a synthesis starting from tyramine.