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Park Kyueun Kim Youngjin Lee Kyung Jin 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(2):487-531
Journal of Radioanalytical and Nuclear Chemistry - An extensive series of evaluations have been performed as part of an IAEA coordinated research project to study a set of nuclear reactions that... 相似文献
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Enhanced solubility of galangin based on the complexation with methylated microbial cyclosophoraoses
Hwanhee Kim Jae Min Choi Youngjin Choi Muhammad Nazir Tahir Yung-Hun Yang Eunae Cho Seunho Jung 《Journal of inclusion phenomena and macrocyclic chemistry》2014,79(3-4):291-300
Methylated cyclosophoraoses (M-Cys) were synthesized by reaction using dimethyl sulfate with native Cys (unbranched cyclic β-1,2-d-glucans) isolated from Rhizobium leguminosarum biovar viciae VF-39. Its structure was proven using nuclear magnetic resonance (1H NMR) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Based on the enhanced hydrophobicity by methylation of Cys, we investigated the inclusion property with the water-insoluble flavonoid, galangin, through a phase solubility study using ultraviolet–visible spectroscopy. The solubility of galangin was enhanced 5.6-fold according to the added concentrations (1 mM) of M-Cys, compared to the 1.9-fold and 3.4-fold enhancements by β-Cyclodextrin (β-CD) and heptakis (2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD), respectively. M-Cys was also shown to have the highest binding constant (5,534 M?1) with galangin among the tested host molecules (β-CD, DM-β-CD, Cys, and M-Cys). From this result, we can infer that the complex of galangin with M-Cys is more stable than any of the other host molecules. The continuous variation method showed that the galangin/M-Cys complex was suitable for 1:1 stoichiometry. The formation of the complex was confirmed with 1H NMR, FT-IR, differential scanning calorimetry, and scanning electron microscopy. Furthermore, the hypothetical molecular model of 1:1 galangin/M-Cys complex was suggested by molecular docking simulations. The cytotoxicity to the human cervical adenocarcinoma cell lines was enhanced by the galangin/M-Cys complex compared with free galangin. The obtained results indicate that M-Cys can be utilized as an effective complexing agent for galangin. 相似文献
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Youngjin Bae 《Israel Journal of Mathematics》2014,204(1):417-430
We study the growth rate of a sequence which measures the uniform norm of the differential under the iterates of maps. On symplectically hyperbolic manifolds, we show that this sequence has at least linear growth for every non-identical symplectomorphisms which are symplectically isotopic to the identity. 相似文献
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[Structure: see text] Unique core-modified porphyrinoids, such as oxabenziporphyrins, oxapyriporphyrins, and thiapyriporphyrins, bearing exocyclic C-C double bonds at meso-positions, have been synthesized and characterized. The synthesis was accomplished by utilizing typical "3+1"-type condensation. Two different stable tautomeric forms were isolated, and the two tautomeric forms can be interconvertible upon treatment with base. In contrast, only the structure bearing an exocyclic double bond was isolated in the case of oxapyriporphyrin and oxabenziporphyrin. 相似文献
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A novel chemical cyclization method using BBr3 has been successfully developed to prepare ladder-type conjugated systems. The cyclized ladder compounds revealed an extended conjugation due to planarization of the structures. The extended ladder polymer can also be easily prepared by our chemical cyclization method using a soluble precursor. 相似文献
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In this Letter, we explore plasmonics-based spatially activated light microscopy (PSALM) for sub-diffraction-limited imaging of biomolecules. PSALM is based on the spatially switched activation of local amplified electromagnetic hot spots under multiple light incidence conditions. The hot spots are associated with surface plasmons that are excited and localized by surface nanostructures. The feasibility of the concept was demonstrated by imaging fluorescent nanobeads on a two-dimensional gold nanograting of a 100-nm-wide grating ridge, the size of which is the measure of the imaging resolution. The result confirms the performance of PSALM for imaging nanobeads at a resolution below the conventional diffraction limit. 相似文献