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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Magnetic Resonance Society
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Korean Magnetic Resonance Society
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Volume & Issues
Volume 6, Issue 2 - Dec 2002
Volume 6, Issue 1 - Jun 2002
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Solid State NMR Study on the Dynamics of the Poly(vinyl butylal) with Various Water Contents
Hyun Namgoong ; Kim, Jong-Soo ; Han, Oc-Hee ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 1~11
Physical properties of PVB [Poly(vinyl butyral)] polymer are strongly correlated with water contents in the polymer. Thus dynamics of PVB containing 10~50(w/w) ％ of water were studied by
C CP/MAS/DD over the temperature range 293K -348K. From the Peak area, line width, chemical shift, and relaxation times (
) measured at 9.4 T, it was deduced that water facilitates molecular dynamics of the PVB molecules overall including conformational exchange of the racemic and meso butyaldehyde rings in the PVB. However, the influence of water was not linear to the amount of water in the PVB samples. It is suggested that water up to 30 w/w ％ of the sample is closely bound to the PVB polymer and water relatively free from the PVB polymer starts to appear when water is added more than 30 w/w ％.％.
An application of wavelet transform toward noisy NMR peak suppression
Kim, Daesung ; Kim, Dai-Gyoung ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 12~19
A shift-averaged Haar wavelet transform was introduced as a new and excellent tool to distinguish real peaks from the noise contaminated NMR signals. It is based on Haar wavelet transform and translation-invariant denoising process. Donoho＇s universal threshold was newly introduced to the shift-averaged Haar wavelet transform for the purpose of automated noise suppression, and was quantitatively compared with the conventional uniform threshold method in terms or threshold and signal to noise ratio (SNR). New algorithm was combined with a routine to suppress a large solvent peak by singular value decomposition (SVD). Combined algorithm was applied to the real spectrum that containing large solvent peak.
Comparative Evaluation of Mn(II) Framework Substitution in MnAPSO-34 and Mn-impregnated SAPO-34 Molecular Sieves Studied by Electron Spin Resonance and Electron Spin Echo Modulation Spectroscopy
Gernho Back ; Kim, Yanghee ; Cho, Young-Soo ; Lee, Yong-Ill ; Lee, Chul-Wee ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 20~37
MnAPSO-34 and Mn-impregnated SAPO-34(Mn-SAPO-34) sample were prepared with various manganese contents and studied by electron spin resonance(ESR) and electron spin echo modulation(ESEM). Electron spin echo modulation analysis of 0.07mo1 ％ Mn(relative to p) in MnAPSO-34 with adsorbed D
O shows two deuteriums at 0.26 nm and two at 0.36 nm from Mn. This suggests that two waters hydrate an MnO
configuration with a D-O bond orientation for the waters as expect for a negatively charged site at low manganese content (0.1 mol％), the ESR spectra of MnAPSO-34 and MnH-SAPO-34 exhibit the same parameters(g 2.01 and A 89 G), but the spectra obtained from MnAPSO-34 samples are better resolved. The decomposition temperature of as-synthesized MnAPSO-34 were in the range of 200-600
of the morpholine which is 12
higher than that in as-synthesized MnH-SAPO-34. Infrared spectra showed that the position of a band at 3450
/ shifted about 15
/ toward higher energy in MnAPSO-34 versus MnH-SAPO-34. The modulation depth of the two-pulse ESE of MnAPSO-34 with adsorbed D
O is deeper than that of MnH-SAPO-34 with adsorbed D
O. Three-pulse ESEM of MnAPSO-34 and MnH-SAPO-34 with adsorbed deuterium oxide shows that the local environments of manganese in the hydrated samples are different, suggesting that Mn(II) is framework substituted in MnAPSO-34 since it obviously occupies an extraframework position in MnH-SAPO-34.
Comparison of Metal Cleaning Effect on Pt Particles Supported on Carbon and Pt Black Observed by NMR, CV, and TEM
Han, Kee-Sung ; Han, Oc-Hee ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 38~44
60% Pt on Vulcan XC-72 with similar Pt sizes to fuel cell grade Pt black was investigated by
13/C nuclear magnetic resonance spectroscopy (NMR), cyclic voltammery (CV), transmission electron microscopy (TEM). Experiments were carried out on electrochemically cleaned samples as well as as-received. The TEM and CV results showed that the average particle sizes were changed by cleaning. However, the chemical shift （
13/CO absorbed on Pt surfaces did not show any appreciable variation with particle size change as did in Pt black. These results indicate that a combination of different analytic techniques is essential to understand the properties of the metal particle catalysts and that the presence of carbon black support strongly influences the NMR data, probably through metal-support interaction.
Evaluation of SPECT Analysis in Patients with Transient Global Amnesia
Choe, Bo-Young ; Kim, Euy-Neyng ; Chung, Yong-An ; Sohn, Hyung-Sun ; Kim, Sung-Hoon ; Chung, Soo-Kyo ; Lee, Hyoung-Koo ; Suh, Tae-Suk ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 45~53
Objectives: This study investigated alterations in regional cerebral blood flow (rCBF) in patients with transient global amnesia (TGA) using statistical parametric mapping 99 (SPM99). Methods: Noninvasive rCBF measurements using 99mTc-ethyl cysteinate dimer (ECD) SPECT were performed on 8 patients with TGA who have ongoing symptoms and 17 age matched controls. The relative rCBF maps in patients with TGA and controls were compared. Results: In patients with TGA, significant decreased rCBF was found along the L superior temporal extending to L parietal region of the brain and L thalamus. There were areas of increased rCBF in the R temporal, R frontal region and R thalamus. Conclusion: We could demonstrate decreased perfusion in left cerebral hemisphere and increased perfusion in right cerebral hemisphere in patients with TGA using SPM99. The imbalanced change of rCBF between bilateral cerebral hemisphere in patients with TGA might suggest that imbalanced neuronal activity between the bilateral hemispheres may have strong relationship to the pathogenesis of the TGA. For quantitative SPECT analysis in TGA patients, we recommend SPM99 rather than the ROI method because of its definitive advantages.
Structural Studies on RUNX of Caenorhabditis elegans by Spectroscopic Methods
Son, Woo-Sung ; Kim, Jong-Wan ; Ahn, Hee-Chul ; Park, Sung-Jean ; Bae, Suk-Chul ; Lee, Bong-Jin ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 54~68
PEBP2/CBF (Polyomavirus Enhancer-core Binding Protein 2/Core Binding Factor), represents a new family of heterodimeric transcription factor. Those members play important roles in hematopoiesis and osteogenesis in mouse and human. PEBP2/CBF is a sequence-specific DNA binding protein. Each member of the PEBP2/CBF family of transcription factors is composed of two subunits,
. The evolutionarily conserved 128 amino acid region in
subunit has been called the Runt domain, which harbors two different activities, the ability to bind DNA and interact with the
subunit. Recently, cDNA clones encoding the C. elegans Runt domain were isolated by screening a cDNA library. This gene was referred to run (Runt homologous gene). In this study, the basic experiments for the structural characterization of RUN protein were performed using spectroscopic methods. We have identified the structural properties of RUN using bioinformatics, CD and NMR. The limit temperature of the structural stability was up to 60
with irreversible thermal process, and the structure of RUN seems to adopt
helices and one or more
sheet or turn. The degree of NMR peak dispersion and intensity was increased by addition of glycine. Therefore, glycine could be used to alleviate the aggregation property of RUN in NMR experiment.
Isolation, structure elucidation and physicochemical properties of novel antibiotic polypeptide,
polypeptide from Streptomyces sp. DWGS2
Donghyuk Shin ; Kim, Daesung ; Lee, Deoggeun ; Lee, Hyeongkyu ; Hoshik Won ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 69~77
During the screening of material which has the antimicrobial activity against aminoglycoside-resistant bacteria, A new material
-Iysine) polypeptide from a culture medium of Streptomyces sp.(DWGS2) was isolated, and the structure and the physicochemical properties of the new material were elucidated. The new material was separated by column chromatography of the culture medium using Dowex1
2, Silica gel, and Sephadex LH20 etc. The chemical structure and molecular weight were determined with the data of various NMR experiments, MALDI mass, and ESI mass experiments. The antimicrobial activity of
-Iysine) polypeptide is not only better than equal to the activity of known aminoglycoside type of antibiotics(MIC=3.125 - 6.25ug/mL) but also effective against aminoglycoside-resistant bacteria and fungi. If the mechanism of antimicrobial activity against aminoglycoside- resistant bacteria is figured out, the
-Iysine) polypeptide can be utilized for the treatment of diseases caused by aminoglycoside-resistant bacteria.
NMR Signal Assignment of a New Quinolone Antibiotic Substance
Donghyuk Shin ; Kim, Daesung ; Yongho Jung ; Hoshik Won ;
Journal of the Korean Magnetic Resonance Society, volume 6, issue 1, 2002, Pages 78~83
A new fluoroquinolone (DW-116) with a broad antibacterial spectrum was synthesized by introducing functional fluoropyridyl and methylpyrazine groups on N1, C7 position of quinolone moiety, respectively.
C NMR signal assignments and structure were completely elucidated by 2D-NMR methods. Physicochemical properties of products were also investigated. DW-116 is decomposed at 306.9
and the decomposition starts at around 285
. The free base form is melt at 280.7
and started to be decomposed immediately. DW-116 has two kinds of polymorphism which is important in drug action but these two plate and rod types have the same solubility in water. However the solubility is quite different in less or polar solvent. The plate type is more soluble in less polar solvent except in dichloromethane.