• 한국자기공명학회:학술대회논문집
• /
• 한국자기공명학회 2000년도 제17회 학술발표회
• /
• pp.31-31
• /
• 2000

• Archives of Pharmacal Research
• /
• 제12권4호
• /
• pp.310-312
• /
• 1989

Three new sesquiterpene alkaloids, tripterregeline, A, B and C were isolated from the stem bark of Tripterygium regelii and their partial structures were determined by various spectroscopic methods.

• Bulletin of the Korean Chemical Society
• /
• 제34권3호
• /
• pp.823-826
• /
• 2013

A low-${\varepsilon}$ solid-state NMR(Nuclear Magnetic Resonance) probe was developed for the spectroscopic analysis of two-dimensional $^{15}N-^1H$ heteronuclear dipolar coupling in dilute membrane proteins oriented in hydrated and dielectrically lossy lipid environments. The system employed a 800 MHz narrow-bore magnet. A solenoid coil strip shield was used to reduce deleterious RF sample heating by minimizing the conservative electric fields generated by the double-tuned resonator at high magnetic fields. The probe's design, construction, and performance in solid-state NMR experiments at high magnetic fields are described here. Such high-resolution solid-state NMR spectroscopic analysis of static oriented samples in hydrated phospholipid bilayers or bicelles could aid the structural analysis of dilute biological membrane proteins.

• 한국자기공명학회논문지
• /
• 제4권2호
• /
• pp.125-132
• /
• 2000

The detailed $^1$H and $^{13}$ C NMR assignments of a novel sucrose isovaleryl ester isolated from the seed of Euphorbia Lathyris L., were achieved by one-and two-dimensional techniques. The new sucrose ester was characterized as an $\alpha$-D-glucopyranoside, 3,4,6-tris-O-(3-methyl-1-oxobutyl)-$\beta$-D-fructofuranosyl, 2,6-bis(3-methylbutanoate); sucrose 4,7,8,11,12-pentaisovalerate by MS and NMR experiments.

• 대한의용생체공학회:의공학회지
• /
• 제15권4호
• /
• pp.413-418
• /
• 1994

In electrical impedance tomography (EIT), we use boundary current and voltage measurements to provide the information about the cross-sectional distribution of electrical impedance or resistivity One of the major problems in EIT has been the inaccessibility of internal voltage or current data in finding the internal impedance values. We propose a new image reconstruction method using internal current density data measured by NMR. We obtained a two-dimensional current density distribution within a phantom by processing the real and imaginary MR images from a 4.7T NMR machine. We implemented a resistivity image reconstruction algorithm using the finite element method and sensitivity matrix. We presented computer simulation results of the image reconstruction algorithm and furture direction of the research.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
• /
• pp.179.2-179.2
• /
• 2003

The cytotoxic activity of 13(E)-Labd-13-ene-8$\alpha$, 15-diol(1), isolated from the ethanol extract of Brachyglottis monroi was evaluated against tumor cell lines such as P388, SNU-C4 MDA-MB231, B 16 melanoma and A549 in vitro. By mean of spectral analysis particularly by the aid of various two dimensional NMR experiments, 1H-NMR and 13C-NMR signals of (1) was completely assigned, and thus the structure of (1) was established unambiguously. (omitted)

• BMB Reports
• /
• 제32권3호
• /
• pp.288-293
• /
• 1999

In order to understand the initial interaction of the substrates malonate, ATP, and CoA with malonyl-CoA synthetase, the catalytic product malonyl-CoA was characterized by NMR spectroscopy and molecular modeling. To assign proton and carbon chemical shifts, two-dimensional $^1H-^1H$ DQF-COSY and $^1H-^{13}C$ HMBC experiments were used. The structure of malonyl-CoA in the solution phase was determined based on distance constraints from NOESY and ROESY spectra. The structures were well-converged around the pantetheine region with the pairwise RMSD value of 0.08 nm. The solution structure exhibited a compact folded conformation with intramolecular hydrogen bonds among its carbonyl and hydroxyl groups. These findings will help us to understand the initial interaction of malonate and CoA with malonyl-CoA synthetase.

• 한국자기공명학회논문지
• /
• 제5권1호
• /
• pp.29-36
• /
• 2001

The structures of two VBS (viral binding site) RNAs, SL1 and SL2, of Yeast Saccharomyces cerevisiae vims have been studied by 2D and 3D NMR experiments. VBSs play a crucial role in viral particle binding to the plus strand and packaging of the RNA. The secondary structures of the two VBS RNAs share a common feature of the stem-internal loop-stem-hairpin loop structure although the size of the internal loops of SL1 and SL2 differs. 2D experiments were sufficient for fill assignments of SL1. However, isotope labeling of the sample and multidimensional experiments were required for 28-nucleotide-long SL2 due to the spectral overlap. Several 3D HCCH experiments have accomplished full assignment of SL2 RNA.

• Bulletin of the Korean Chemical Society
• /
• 제28권8호
• /
• pp.1294-1298
• /
• 2007

Two new compounds lanast-5,8-dien-3β-ol-27-oic acid-3β-D-glucopyranosyl (4'-1'')-10'',11''-dimethoxy anthracene (1), 2-methoxy-6-(n-nonacontan-5'',6''-dionyl)-11-hydroxy-13-methyl-11β-D-rhamnopyranoside anthracene (2) have been isolated from the hairy root cultures of Catharanthus roseus. Their structures have been elucidated with the help of 500 MHz NMR using one- and two-dimensional NMR in combination with IR, EI/MS, FAB/MS and HRFABMS spectroscopy.

• Bulletin of the Korean Chemical Society
• /
• 제31권2호
• /
• pp.379-383
• /
• 2010

Metabolites of colorectal cancer tissues from 12 patients were analyzed and compared with those of the normal tissues by two-dimensional NMR spectroscopy. NMR data were analyzed with the help of the metabolome database and the statistics software. Cancerous tissues showed significantly altered metabolic profiles as compared to the normal tissues. Among such metabolites, the concentrations of taurine, glutamate, choline were notably increased in the cancerous tissues of most patients, and those of glucose, malate, and glycerol were decreased. Changes in individual metabolites varied significantly from patient to patient, but the combination of such changes could be used to distinguish cancerous tissues from normal ones, which could be done by PCA analysis. The traditional chemometric analysis was also performed using AMIX software. By comparing those two results, the analysis via $^1H-^{13}C$ HSQC spectra proved to be more robust and effective in assessing and classifying global metabolic profiles of the colorectal tissues.