• Journal of the Korean Magnetic Resonance Society
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• v.9 no.1
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• pp.29-37
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• 2005

Intra-cellular drug uptake in Xenopus laevis oocyte has been elucidated using localized MR spectroscopy (MRS) and PFG NMR techniques at a 600 $MH_z$(Bruker, 14.1 T) NMR spectrometer. The localized MRS has been done with a homemade probe, and shows the intra-cellular uptake of nicotinamide. The self-diffusion of the molecule in Xenopus oocyte was obtained by PFG NMR technique. The measured data are well fitted with a linear combination of two exponential functions, which shows that there are two types of drug molecules, intra-and extra-cellular molecules. Diffusion coefficients of intra- and extra-cellular drug molecules are 3.7 $\times$ $10^{-11}$ $\m^{2}/s$and 6.4 $\times$ $10^{-10}$ $\m^{2}/s$, respectively. In the weighting factors there is shown that about 5% of drug molecule is inside the cells. These techniques can be used for drug screening in molecule-, cell-, and tissue-based preclinical test.

• The Korea Journal of Herbology
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• v.23 no.3
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• pp.27-32
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• 2008

Objectives : In this paper, we describe that $^1H-NMR$ spectroscopy may be superior to the conventional HPLC for the quantitative analysis of hesperidin from Citrus unshiu. Methods : $^1H-NMR$ spectra (400 MHz) were recorded in $DMSO-d_6$ using a Varian UNITY Inova AS 400 FT NMR spectrometer. One hundred milligram of powdered Citrus unshiu was weighed out and mixed with 1 ml of $DMSO-d_6$ with sonication for 30 min (room temperature). The extracts were filtrated through a 0.45 ${\mu}m$ PVDF filter and 0.5 ml of filtrated extract used for quantitative $^1H-NMR$ measurement (added 1 mg of dimethyl terephthalate as internal standard). The quantity of hesperidin was calculated by the ratio of the intensity of the compound to the known amount of internal standard. For HPLC analysis, the half gram of plant material was extracted with 60 ml of MeOH for 2 hours. The extracts were made 100 ml volume and analyzed by a Waters HPLC system using a YMC ODS column. The total flow rate was 1.0 ml/min with a sample volume 10 ${\mu}l$ and UV detection at 280nm. Results : The contents of hesperidin in Citrus unshiu was determined $5.33{\pm}0.06$% in the quantitative $^1H-NMR$ method and $5.15{\pm}0.12%$ in HPLC method. Using the quantitative $^1H-NMR$ the contents of hesperidin can be determined in much shorter time than the conventional HPLC measurements. Conclusions : From those results, the advantages of quantitative $^1H-NMR$ analysis are that can be analyzed to identify and quantify, and no reference compounds required for calibration curve. Besides, it allows rapid and simple quantification for hesperidin with an analysis time for only 10 min without any pre-purification steps.

• Journal of the Korean Magnetic Resonance Society
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• v.25 no.2
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• pp.12-16
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• 2021

Daphnia magna is used as target organism for environmental metabolomics. The metabolome of D. magna was studied with NMR spectroscopy. Most studies used the extract of D. magna, but the reproducibility cannot be obtained using extracted sample. In this study, lyophilized D. magna samples were analyzed with two different ¹H NMR techniques, HR-MAS on intact tissues and solution NMR on extracted tissues. Samples were measured three times using 600 MHz NMR spectrometer. Metabolite extraction required more than twice as many D. magna, but the metabolite intensity was lower in solution NMR. In the spectra of HR-MAS NMR, the lipid signal was observed, but they did not interfere with metabolite profiling. We also confirmed the effect of swelling time on signal intensities of metabolites in HR-MAS NMR, and the results suggest that appropriate swelling should be used in lyophilized D. magna to improve the accuracy of metabolite profiles.

• Analytical Science and Technology
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• v.9 no.2
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• pp.203-209
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• 1996

Kaminsky catalyst system($Et(Ind)_2ZrCl_2$ and MAO(methylaluminoxane)) was prepared. Propylene was polymerized at $60^{\circ}C$ in this system. The microstructure was studied by using the $^{13}C$ NMR spectrometer. From the $^{13}C$ NMR data, the 2, 1-insertion of propylene was controlled stereospecific by Kaminsky catalyst due to the structures of meso and racemo I. After the 2, 1-insertion of propylene, 1, 2-insertion of the chain end was less stereospecifically controlled by the catalyst.

• Journal of Biomedical Engineering Research
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• v.8 no.2
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• pp.145-150
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• 1987

Urine NMR analyses made by use of an 80 MHz proton NMR spectrometer show that aromatic proton NMR signals appear in most censer patients'urine. On the assumption that the signals may be caused by the phenolic compound of tyrosine excreted in the urine, a jellied reagent is used for identifying them by observing the urine color reaction. It is observed that the reagent reacted to the cancer urine becomes red. Such a change of the urine color seems to indicate the substance of tyrosine. Recently an attempt to determine the reagent sensitivity an specificity of the urine of 69 persons including cancer and noncancer patients has been made. The results of the attempt are respectively 85.3% for sensitivity and 91.4% for specificity. This seems to show a possibility that the reagent can be used for the diagnosis.

• Journal of the Korean Magnetic Resonance Society
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• v.21 no.4
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• pp.145-151
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• 2017

Rhodiola rosea, also known as gold root or rose root, is a perennial plant in the family of Crassulaceae. The rhizhome of R. rosea has been widely used as a hemostatic, tonic for burns and contusions in traditional Chinese medicine. Recent studies reported its strong antioxidant and adaptogenic properties. In this paper, we attempted to isolate compounds from the methanolic extract of R. rosea rhizomes. Four compounds including one new compound (1), two kaempferol glycosides (3 and 4) were isolated from chloroform and ethyl acetate soluble fraction of R. rosea extract. The structures of 1~4 including relative stereochemistry were determined by MS and NMR analysis.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.2
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• pp.84-90
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• 2012

It is described that the total analysis of CD-R, a digital recording media, including the planning and performing chemical analysis of cross sectional structure of recording layer, dye composition and chemical structure as an example of design for chemical analysis. Since chemical analysis of unknown sample is often involved the complicated process requiring many experiences and knowledge, students feel difficulties in planning the procedure of chemical analysis and selecting analytical methods. Thus, an example of chemical analysis is provided here to help student understanding the hole procedure of CD-R analysis. In this study, SEM is used to determine the cross sectional structure of PC substrate and recoding layer of CD-R. The dyes in recording layer is dissolved with solvent and separated with using TLC, analyzed with using UV-Vis absorption spectrometer. Then, the chemical structure of each component is determined with using GC-MS, NMR and mass spectrometer.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.51-55
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• 2017

To obtain Nuclear Magnetic Resonance (NMR) measurement of membrane protein, an NMR magnet is required to generate high intensity, homogeneity, and stability of field. A High-Temperature Superconducting (HTS) magnet is a promising alternative to a conventional Low-Temperature Superconducting (LTS) NMR magnet for high field, current density, and stability margin. Conventionally, an HTS coil has been wound by several winding techniques such as Single-Pancake (SP), Double-Pancake (DP), and layer-wound. The DP winding technique has been frequently used for a large magnet because long HTS wire is generally difficult to manufacture, and maintenance of magnet is convenient. However, magnetic field generated by the slanted turns and the splice leads to field inhomogeneity in Diameter of Spherical Volume (DSV). The field inhomogeneity degrades performance of NMR spectrometer and thus effect of the slanted turns and the splice should be analyzed. In this paper, field gradient of HTS double-pancake coils considering the slanted turns and the splice was calculated using Biot-Savart law and numerical integration. The calculation results showed that magnetic field produced by the slanted turns and the splice caused significant inhomogeneity of field.

• Progress in Superconductivity and Cryogenics
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• v.18 no.3
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• pp.21-24
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• 2016

Recently, production technique and property of the High-Temperature Superconductor (HTS) tape have been improved. Thus, the study on applying an HTS magnet to the high magnetic field application is rapidly increased. A Nuclear Magnetic Resonance (NMR) spectrometer requires high magnitude and homogeneous of central magnetic field. However, the HTS magnet has fabrication errors because shape of HTS is tape and HTS magnet is manufactured by winding HTS tape to the bobbin. The fabrication errors are winding error, bobbin diameter error, spacer thickness error and so on. The winding error occurs when HTS tape is departed from the arranged position on the bobbin. The bobbin diameter and spacer thickness error occur since the diameter of bobbin and spacer are inaccurate. These errors lead magnitude and homogeneity of central magnetic field to be different from its ideal design. The purpose of this paper is to investigate the effect of winding error, bobbin diameter error and spacer thickness error on the central field and field homogeneity of HTS magnet using the virtual NMR signals in MATLAB simulation.

• Journal of Biosystems Engineering
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• v.28 no.3
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• pp.261-268
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• 2003

Ten MHz pulsed NMR spectrometer was used to measure the magnetic resonance characteristics of Korean red ginseng. The difference in the internal structures of good and bad red ginsengs was examined by their NMR characteristics. Average values of $T_1$ and free induction decay(FID) ratios of under grade Korean red ginseng were the highest among the three groups categorized as normal, medium and under grades Korean red ginseng and average values of $T_2$ and $T_2$$^{＊}$ of them were the lowest among the three groups. Principal component analysis(PCA) was used to observe the contribution of measured NMR values to the grade of Korean red ginseng. The measured $T_1$, $T_2$, $T_2$$^{＊}$ and FID ratio of 79 Korean red ginsengs classified as normal grade, medium grade and under grade were examined using PCA analysis. Cumulative variance of PC1 through PC3 occupied more than 90% of total variance at first and second NMR measurement. Plots of PC scores for the most important PCs showed that normal red ginseng samples were distributed around the left region of PC1 axis and most of the undergrade red ginseng samples were scattered around the right region of PC1 axis.