• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1985년도 춘계학술대회
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• pp.44-47
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• 1985

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1998년도 동계 학술대회 논문집
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• pp.331-336
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• 1998

• Natural Product Sciences
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• 제22권1호
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• pp.30-34
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• 2016

A simple and rapid method based on proton nuclear magnetic resonance spectroscopy was developed for determination of trans-anethole content in fennel essential oil. Spectra of pure trans-anethole, of the pure essential oil of fennel, and of the pure oil of fennel with thymol internal standard were recorded. The signal of $H-1^/$ was used for quantification of trans-anethole. This proton signal is well separated in the proton magnetic resonance spectrum of the compound. No reference compound is needed and cheap internal standard was used. The results obtained from spectroscopic analysis were compared with those obtained by gas chromatography. Additionally, the developed method was used for determination of the type of vegetable oil used as a carrier in commercial products, which cannot be quantified as such by gas chromatography. This study demonstrates the application of proton nuclear magnetic resonance spectroscopy as a quality control method for estimation of essential oil components.

• 대한화학회지
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• 제19권4호
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• pp.233-239
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• 1975

세개의 二重結合에 衣하여 conjugate된 비대칭화합물 cis-2-bitenedialdioxime의 두 oxime group의 configuration을 溶媒, 溫度 및 濃度의 影響에 대한 NMR 硏究로서 決定하였다. 溶液狀態에서의 이 化合物은 $-35^{circ}$∼$-95^{\circ}C$의 溫度條件下에서는 항상 "syn-syn" configuration으로 存在함을 알았다. 또한 이 化合物의 oxime group과 溶媒사이의 水素結合의 相對的强度와 溫度 및 濃度에 의 피리딘의 考察하고 몇가지 水素結合의 모델을 提示하였다. 特히 피리딘溶媒 속에서는 水素結合은 한 영향을 窒素가 갖고 있는 非共有電子雙에 衣해서 일어나지 않고, oxime 의 hydroxyl proton과 피리딘의 $\pi$軌道函數 사이에 形成되는 $\pi$-착물의 結果임을 알았다.

• Journal of Animal Science and Technology
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• 제64권2호
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• pp.247-261
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• 2022

Ketosis is associated with high milk yield during lactating or insufficient feed intake in lactating dairy cows. However, few studies have been conducted on the metabolomics of ketosis in Korean lactating dairy cows. The present study aimed to investigate the serum and urine metabolites profiling of lactating dairy cows through proton nuclear magnetic resonance (¹H-NMR) spectroscopy and comparing those between healthy (CON) and subclinical ketosis (SCK) groups. Six lactating dairy cows were categorized into CON and SCK groups. All experimental Holstein cows were fed total mixed ration. Serum and urine samples were collected from the jugular vein of the neck and by hand sweeping the perineum, respectively. The metabolites in the serum and urine were determined using ¹H-NMR spectroscopy. Identification and quantification of metabolites was performed by Chenomx NMR Suite 8.4 software. Metabolites statistical analysis was performed by Metaboanalyst version 5.0 program. In the serum, the acetoacetate level was significantly (p < 0.05) higher in the SCK group than in the CON group, and whereas acetate, galactose and pyruvate levels tended to be higher. CON group had significantly (p < 0.05) higher levels of 5-aminolevulinate and betaine. Indole-3-acetate, theophylline, p-cresol, 3-hydroxymandelate, gentisate, N-acetylglucosamine, N-nitrosodimethylamine, xanthine and pyridoxine levels were significantly (p < 0.05) higher in the urine of the SCK group than that in the CON group, which had higher levels of homogentisate, ribose, gluconate, ethylene glycol, maltose, 3-methyl-2-oxovalerate and glycocholate. Some significantly (p < 0.05) different metabolites in the serum and urine were associated with ketosis diseases, inflammation, energy balance and body weight. This study will be contributed useful a future ketosis metabolomics studies in Korea.

• Journal of Photoscience
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• 제9권2호
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• pp.110-113
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• 2002

We demonstrate here a dynamic structure of bacteriorhodopsin (bR) as revealed by $^{13}$ C NMR studies on [3_$^{13}$ C]_,[1-$^{13}$ C]Ala- and/or Val-labeled wild type and a variety of site-directed mutants at ambient temperature. For this purpose, well-resolved (up to twelve) I$^{13}$ C NMR peaks were assigned with reference to the displacement of peaks due to the conformation-dependent I$^{13}$ C chemical shifts and reduced peak-intensities due to site-directed mutations. Revealed bR structure was not rigid as anticipated from 2D crystals of hexagonal array but a dynamically heterogeneous, undergoing a variety of local fluctuations depending upon specific site with frequency range of 10$^2$ -10$^{8}$ Hz. In particular, dynamics- dependent suppression of peaks turned out to be very sensitive to the motion of 10$^{-4}$ s and 10$^{-5}$ s interfered with frequency of magic angle spinning and proton decoupling, respectively. It is also noteworthy that such dynamic feature is strongly dependent upon the manner of 2D crystalline packing: $^{13}$ C NMR peaks of monomeric bR yielded either highly broadened or completely suppressed signals, depending upon the type of $^{13}$ C-labeled amino-acid residues.

• Macromolecular Research
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• 제15권2호
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• pp.160-166
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• 2007

Novel multiblock copolymers, based on segmented sulfonated hydrophilic-hydrophobic blocks, were synthesized and investigated for their application as proton exchange membranes. A series of segmented sulfonated poly(arylene ether sulfone)-b-polyimide multiblock copolymers, with various block lengths, were synthesized via the coupling reaction between the terminal amine moieties on the hydrophilic blocks and naphthalene anhydride functionalized hydrophobic blocks. Successful imidization reactions required a mixed solvent system, comprised of NMP and m-cresol, in the presence of catalysts. Proton conductivity measurements revealed that the proton conductivity improved with increasing hydrophilic and hydrophobic block lengths. The morphological structure of the multiblock copolymers was investigated using tapping mode atomic force microscopy (TM-AFM). The AFM images of the copolymers demonstrated well-defined nanophase separated morphologies, with the changes in the block length having a pronounced effect on the phase separated morphologies of the system. The self diffusion coefficient of water, as measured by $^1H$ NMR, provided a better understanding of the transport process. Thus, the block copolymers showed higher values than Nafion, and comparable proton conductivities in liquid water, as well as under partially hydrated conditions at $80^{\circ}C$. The new materials are strong candidates for use in PEM systems.

• 한국자기공명학회논문지
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• 제10권2호
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• pp.163-174
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• 2006

Luteinizing Hormone Releasing Hormone(LHRH) is a decapeptide neurotransmitter known to be regulated by metal ions in the hyperthalamus. Zn-binding LHRH complex was systhesized, and zinc-LHRH complex was studied to understand what kinds of structural modifications would be critical in the LHRH releasing mechanism. Both nonexchangeable and exchangeable $^1H-NMR$ signal assignments were accomplished by pH-dependent and COSY NMR experiments. In addition, $^1H-NMR$ chemical shift changes of a-proton and peptide NH NMR signals at different pH condition, and $^1H-NMR$ signal differences between metal free and metallo-LHRH complex was monitored. NMR signals exhibit that primary metal-binding sites are nitrogens donor of imidazole ring and Arg, and peptide oxygen of Pro-His in the sequence. Structure obtained in this study has a cyclic conformation which is similar to that of energy minimized, and exhibits a specific a-helical turn with residue numbers $(2{\sim}7)$ out of 10 amino acids.

• 한국자기공명학회논문지
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• 제23권4호
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• pp.93-97
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• 2019

Black ginger (Kaempferia parviflora) is a short-lived ginger plant with dark purple colored root and is known to be effective in treating diabetes and obesity. To find out the difference in the characteristics of the black ginger according to the variety of production, 1D proton NMR experiments were performed on 4 types of black gingers from different regions. The NMR spectra of all black ginger showed the characteristic peaks of the polymethoxy flavone compounds, and the chemical shifts and intensity of peaks showed slight differences depending of the type of black ginger implying the difference in molecular environment. These initial NMR experiments can be applied to the identification of the diversity of black ginger in physiological function according to the climate of regions using SNIF-NMR (Site-specific Natural Isotope Fractionation studied by NMR).

• 대한의용생체공학회:의공학회지
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• 제10권3호
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• pp.285-288
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• 1989

A characteristic proton NMR signal is found in human cancer serums. The signal is given by $6.43{\pm}0.06$ ppm on average. An attempt is made to find a certain correlation between the appearance of the signal and the amounts of CEA and AFP in the serums.