• Mass Spectrometry Letters
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• v.12 no.4
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• pp.179-185
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• 2021

Collision-induced dissociation (CID) combined with electrospray ionization mass spectrometry (ESI-MS) was used to obtain structural information on rat islet amyloid polypeptide (rIAPP) monomers (M) and dimers (D) observed in the multiply charged state in the MS spectrum. MS/MS analysis indicated that the rIAPP monomers adopt distinct structures depending on the molecular ion charge state. Peptide bond dissociation between L₂₇ and P₂₈ was observed in the MS/MS spectra of rIAPP monomers, regardless of the monomer molecular ion charge state. MS/MS analysis of the dimers indicated that D⁵⁺ comprised M²⁺ and M³⁺ subunits, and that the peptide bond dissociation process between the L₂₇ and P₂₈ residues of the monomer subunit was also maintained. The observation of (M+ b₂₇)⁴⁺ and (M+ y₁₀)³⁺ fragment ions were deduced to originate from the two different D⁵⁺ complex geometries, the N-terminal and C-terminal interaction geometries, respectively. The fragmentation pattern of the [M_rIAPP + M_hIAPP]⁵⁺ MS/MS spectrum showed that the interaction occurred between the two N-terminal regions of M_rIAPP and M_hIAPP in the heterogeneous dimer (hetero-dimer) D⁵⁺ structure.

• Clinical and Experimental Pediatrics
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• v.50 no.12
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• pp.1247-1251
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• 2007

Purpose : Pathologically, Kawasaki disease (KD) is associated with widespread vascular endothelial damage in the acute phase. The vasculitis induced endothelial injury leads to coagulation abnormalities. Abnormalities of endothelial function, platelet activation, and fibrinolysis are present during acute phase and long after the onset of KD. The aim of study is to evaluate the change of hemostatic markers in the clinical stages of KD and to assess the hemostatic markers to be a useful indicator of the development of coronary artery lesion (CAL). Methods : Seventy four KD patients diagnosed in Chungnam National University Hospital from November 2004 to June 2007. Eleven febrile control and eleven healthy children were selected for healthy control. All blood samples were collected before and after Intravenous gammaglobulin (IVGG), $2^{nd}$ week, and $4^{th}-8^{th}$ week of illness of KD. Results : Initial D-dimer level of Kawasaki disease showed meaningful difference compared to control group (P<0.05). D-dimer and fibrinogen degradation products (FDP) before IVGG increased compared with normal control group and decreased after IVGG administration. It is normalized until 2 weeks later, and continue to decreasing. D-dimer and FDP were significantly different according to the CAL before IVGG. Conclusion : The hemostatic markers may change to the clinical stage of KD, which may suggest the degree of endothelial injury. Increased some hemostatic markers may be the predictors for development of CAL.

• Mass Spectrometry Letters
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• v.14 no.4
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• pp.153-159
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• 2023

The copper ion, Cu(II), binding sites for amyloid fragment Aβ1-16 (=Aβ16 ) were investigated to explain the biological activity difference in the Aβ16 aggregation process. The [M+Cu+(z-2)H]^z+ (z = 2, 3 and 4, M = Aβ16 monomer) and [D+Cu+(z-2)H]^z+ (z = 3 and 5, D = Aβ16 dimer) structures were investigated using electrospray ionization (ESI) mass spectrometry (MS) and tandem mass spectrometry (MS/MS). Fragment ions of the [M+Cu+(z-2)H]^z+ and [D+Cu+(z-2)H]^z+ complexes were observed using collision-induced dissociation MS/MS. Three different fragmentation patterns (fragment "a", "b", and "y" ion series) were observed in the MS/MS spectrum of the (Aβ16 monomer or dimer-Cu) complex, with the "b" and "y" ion series regularly observed. The "a" ion series was not observed in the MS/MS spectrum of the [M+Cu+2H]⁴⁺ complex. In the non-covalent bond dissociation process, the [D+Cu+3H]⁵⁺ complex separated into three components ([M+Cu+H]³⁺, M³⁺, and M²⁺), and the [M+Cu]²⁺ subunit was not observed. The {M + fragment ion of [M+Cu+H]³⁺} fragmentation pattern was observed during the covalent bond dissociation of the [D+Cu +3H]⁵⁺ complex. The {M + [M+Cu+H]³⁺} complex geometry was assumed to be stable in the [D+Cu+3H]⁵⁺ complex. The {M + fragment ion of [M+Cu]²⁺} fragmentation pattern was also observed in the MS/MS spectrum of the [D+Cu+H]³⁺ complex. The {M + [y₉+Cu]¹⁺} fragment ion was the characteristic fragment ion. The [D+Cu+H]³⁺ and [D+Cu+3H]⁵⁺ complexes were likely to form a monomer-monomer-Cu (M-M-Cu) structure instead of a monomer-Cu-monomer (M-Cu-M) structure.

• Korean Journal of Crystallography
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• v.15 no.1
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• pp.29-34
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• 2004

The crystal structure of cholesteryl hemisuccinate ($C_{31}H_{50}O_4$) was investigated by X-ray diffraction method. The cholesterol fragment of the title compound were in good agreement with those for related cholesterol derivatives. The unit cell contains four cholesteryl hemisuccinate molecules that are not related by crystal symmetry and have their tetracyclic system almost parellel to each other. There are two pairs of hydrogen-bonded dimer between A and D molecules and B and C molecules. These two hydrogen-bonded dimers are parallel to the c-axis, and are closely packed.

• Journal of the Korean Magnetic Resonance Society
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• v.10 no.1
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• pp.38-45
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• 2006

The NMR and MS techniques were applied to identification and quantitative analysis of oligomers in a commercialized poly (trimethylene terephthalate). Oligomers in a commercialized poly (trimethylene terephthalate) were extracted via a dissolving and reprecipitation method. Analysis of the components of the extract using NMR and MS revealed that it contained mainly cyclic oligomers with degrees of polymerization of 2, 4 and 5 (dimer, tetramer and pentamer). Trimer and cyclic oligomers with degrees of polymerization of more than 6 were not found in the extract in the present study. Quantitative analysis of dimer was performed by NMR spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1422-1432
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• 2014

Convergent all-electron multi-reference configuration-interaction (MRCI) calculations are performed for a lithium dimer with Kaufmann's Rydberg basis functions. A comparison of the results of these calculations with those of the effective core potential/core polarization potential (ECP/CPP) method and experimental data reveals the deficiency of the all-electron ab initio method. The deficiency is related to the mere 51.9% attainment of electron correlation for the ground state. The percent attainment of electron correlation for the first excited state is slightly better than that for the ground state, preventing us from obtaining better agreements with experimental data by means of increasing the size of basis sets. The Kaufmann basis functions are then used with the ECP/CPP method to obtain the accurate convergent potential energy curves for the $^1\prod_u$ states correlated to Li(2p) + Li(2p) and Li(2s) + Li(n = 2, 3, 4). Quantum defect curves (QDCs) calculated for both the $X^2\sum_g$ and 1 $^2\prod_u$ states of the $Li{_2}^+$ ion and the Lu-Fano plot reveal a strong series-series interaction between the two $2snp{\pi}$ and $2pnp{\pi}$ Rydberg series. The QDCs are then used to resolve assignment problems in the literature. The reassignments, performed by Jedrzejewski-Szemek et al., of the dissociation product of the D $^1\prod$ state from (2s+3d) to (2s+3p) and that of the 6 $^1\prod_u$ from (2s+4d) to (2s+4p) are found to be incorrect. It may be more natural to assign their $2snp{\pi}$ Rydberg series as a $2snd{\pi}$ series. The state, assigned as 5p $^1\prod_u$ by Ross et al. and 4d $^1\prod$ by Jedrzejewski-Szemek et al., is assigned as the 7 $^1\prod_u$ state, correlated to the Li(2s) + Li(4f) limit.

• YAKHAK HOEJI
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• v.39 no.6
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• pp.666-670
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• 1995

The plasmin activity of euglobulin fraction treated with earthworm extract(EWE) increased concentration dependently when EWE(0.5, 1.0 and 2.0 mg each) were added to normal plasma. It was shown that lumbrokinase in EWE may be moved to euglobulin fraction and activated plasminogen. Also anticoagulation and fibbrinolysis were studied when EWE(7.5, 30 and 120 mg/kg) were added to rat model. Prothrombin time (PT) were 19.7${\pm}$ 3.8, 22.5${\pm}$ 2.5 and 24.5${\pm}$ 5.0sec. activated partial thromboplastin time (APTT) were 25.7${\pm}$ 5.9, 28.7${\pm}$ 5.2 and 36.5${\pm}$ 19.1 sec. After 15 days, the production of D-dimer were 242.3${\pm}$ 47.4, 250.0${\pm}$ 11.9 and 205.8${\pm}$ 12.2mg/ml plasma, respectively. These data showed that EWE acted on the coagulation factor of intrinsic and extrinsic system.

• Bulletin of the Korean Chemical Society
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• v.21 no.8
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• pp.797-800
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• 2000

The reaction of o-acylthiophenacyl chloride 5a with onc equivalent ofsodium azide in aqueous acetone at-10~ $-5^{\circ}C$ gave 2,9-dimethyl-6H,I3H-dibenzo[d,i][1,6]dithiecin-7,14-dione 7(10%),acyclic dimer 8(64%),and tri-mer 9 (8%). Dimer 8 and trimer 9 we re converted readily to 7 under the similar conditions at room temperature in yields of 72% and 53%,respectivel. Also, one pot synthesis of 7 (64%, 45%) from the reaction of 5a or 5b with two equivalents of sodium azide at room temperature was very successful.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.183-183
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• 1996

Bacteriophage T4 endonuclease V initiates the repair of ultraviolet (UV)-induced pyrimidine dimer photoproducts in duplex DNA. The mechanism of DNA strand cleavage involves four sequential stens: linear diffusion along dsDNA, pyrimidine dimer-specific binding,l pyrimidine dimer-DNA glycosylase activity, and Af lyase activity. Although crystal structure is known for this enzyme, solution structure has not been yet known. In order to elucidate the solution structure of this enzyme NMR spectroscopy was used. As a basis for the NMR peak assignment of the protein, HSQC spectrum was obtained on the uniformly $\^$15/N-labeled T4 endonuclease V. Each amide peak of the spectrum were classified according to amino acid spin systems by interpreting the spectrum of $\^$15/N amino acid-specific labeled T4 endonuclease V. The assignment was mainly obtained from three-dimensional NMR spectra such as 3D NOESY-HMQC, 3D TOCSY-HMQC. These experiments were carried out will uniformly $\^$15/N-labeled sample. In order to assign tile resonance of backbon atom, triple-resonance theree-dimensional NMR experiments were also performed using double labeled($\^$15/N$\^$13/C) sample. 3D HNCA, HN(CO)CA, HNCO, HN(CA)HA spectra were recorded for this purpose. The results of assignments were used to interpret the interaction of this enzyme with DNA. HSQC spectrum was obtained for T4 endonuclease V with specific $\^$15/N-labeled amino acids that have been known for important residue in catalysis. By comparing the spectrum of enzyme*DNA complex with that of the enzyme, we could confirm the important role of some residues of Thr, Arg, Tyr in activity. The results of assignments were also used to predict the secondary structure by chemical shift index (CSI).

• Journal of Neurocritical Care
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• v.11 no.2
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• pp.102-109
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• 2018

Background: A sians were known to have a relatively lower incidence of venous thromboembolism (VTE), and there is insufficient evidence to suggest a specific D-dimer threshold level for screening VTE in patients with acute stroke. Methods: We prospectively enrolled patients with acute ischemic stroke admitted to Jeju National University Hospital. The inclusion criteria were: 1) aged ${\geq}18$ years, 2) admission within seven days of symptom onset, and 3) an initial National Institute of Health Stroke Scale (NIHSS) score >1 for the affected lower limb. Ultrasound scans of the lower limbs and plasma D-dimer assays were performed on days 7-14 and 15-28 after stroke onset. Results: Of 285 patients admitted during the study period, 52 patients met inclusion criteria (mean age 74.5, male 40.4%, median initial NIHSS score 12, and unable to walk unassisted at discharge 76.9%). During 7-14 days, 23 of 52 patients (44.2%) had a D-dimer level above 1.57 mg/L, and 9.6% had a level above 5.50 mg/L. Proximal deep vein thrombosis (DVT) was detected in 3 patients (5.8%, 95% confidence Interval 1.2-16.0%) on ultrasound examination. All DVTs were found in elderly female patients with severe leg weakness. No patient was diagnosed with pulmonary embolism during the study period. Conclusion: The incidence of VTE seems to be very low among Korean patients with acute ischemic stroke. Advanced age, female sex, and severe leg weakness were important risk factors for developing DVT in this study.