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21.
This study compared two methods, corrected (separation of T(1) and T(2)* effects) and uncorrected, in order to determine the suitability of the perfusion and permeability measures through Delta R(2)* and Delta R(1) analyses. A dynamic susceptibility contrast dual gradient echo (DSC-DGE) was used to image the fixed phantoms and flow phantoms (Sephadex perfusion phantoms and dialyzer phantom for the permeability measurements). The results confirmed that the corrected relaxation rate was linearly proportional to gadolinium-diethyltriamine pentaacetic acid (Gd-DTPA) concentration, whereas the uncorrected relaxation rate did not in the fixed phantom and simulation experiments. For the perfusion measurements, it was found that the correction process was necessary not only for the Delta R(1) time curve but also for the Delta R(2)* time curve analyses. Perfusion could not be measured without correcting the Delta R(2)* time curve. The water volume, which was expressed as the perfusion amount, was found to be closer to the theoretical value when using the corrected Delta R(1) curve in the calculations. However, this may occur in the low concentration of Gd-DTPA in tissue used in this study. For the permeability measurements based on the two-compartment model, the permeability factor (k(ev); e = extravascular, v = vascular) from the outside to the inside of the hollow fibers was greater in the corrected Delta R(1) method than in the uncorrected Delta R(1) method. The differences between the corrected and the uncorrected Delta R(1) values were confirmed by the simulation experiments. In conclusion, this study proposes that the correction for the relaxation rates, Delta R(2)* and Delta R(1), is indispensable in making accurate perfusion and permeability measurements, and that DSC-DGE is a useful method for obtaining information on perfusion and permeability, simultaneously. 相似文献
22.
Huh S Wiench JW Trewyn BG Song S Pruski M Lin VS 《Chemical communications (Cambridge, England)》2003,(18):2364-2365
A synthetic method has been developed that can control both multifunctionalization and morphology of the mesoporous organic-inorganic hybrid materials by introducing different molar ratios of organoalkoxysilane precursors to a base-catalyzed co-condensation of silicate. 相似文献
23.
Three new tetrahydrofuran-type sesquilignans, called saucerneol A, saucerneol B and saucerneol C were isolated from the underground parts of Saururus chinensis (Saururaceae), together with known lignans, di-O-methyltetrahydrofuriguaiacin B, machilin D and machilin D 4-methyl ether. Their structures were established from several spectral data. 相似文献
24.
Sukmoon Huh 《Annali di Matematica Pura ed Applicata》2011,190(2):195-208
We investigate the jumping conics of stable vector bundles E of rank 2 on a smooth quadric surface Q with the first Chern class c1 = OQ(-1,-1){c_1= \mathcal{O}_Q(-1,-1)} with respect to the ample line bundle OQ(1,1){\mathcal {O}_Q(1,1)} . We show that the set of jumping conics of E is a hypersurface of degree c
2(E) − 1 in
\mathbb P3*{\mathbb {P}_3^{*}} . Using these hypersurfaces, we describe moduli spaces of stable vector bundles of rank 2 on Q in the cases of lower c
2(E). 相似文献
25.
26.
Md. Abdul Aziz Kyungmin Jo Md. Abdul Qaium Chan‐Hwa Huh In Seok Hong Haesik Yang 《Electroanalysis》2009,21(19):2160-2164
We report a versatile platform for highly sensitive alkaline phosphatase (ALP)‐based electrochemical biosensors that uses an avidin‐modified indium tin oxide (ITO) electrode as a sensing electrode and 1‐naphthyl phosphate (NPP) as an ALP substrate. Almost no electrocatalytic activity of NPP and good electrocatalytic activity of 1‐naphthol (ALP product) on the ITO electrodes allow a high signal‐to‐background ratio. The effective surface covering of avidin on the ITO electrodes allows very low levels of nonspecific binding of proteins to the sensing electrodes. The platform technology is used to detect mouse IgG with a detection limit of 1.0 pg/mL. 相似文献
27.
Dal Ho Huh 《Tetrahedron》2004,60(44):9857-9862
Various 2-arylmethylimidazolines were prepared by treating readily available 2-aryl-1,1-dibromoethenes with ethylenediamine under mild conditions and further converted into the corresponding imidazoles smoothly with Swern oxidation. 相似文献
28.
Seong Huh Young Jun Park Alan. J. Lough Moo‐Jin Jun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):416-417
The title compound, [RuH(C6H8BN4)(C21H21P)2(CO)], possesses two trans‐disposed tri‐p‐tolylphosphines in axial positions and the remaining ligands in equatorial positions. The overall geometry of the RuII ion is a distorted octahedral structure. The P—Ru—P axis deviates from linearity by about 13°. This distortion arises mainly from the steric congestion between the bulky phosphine moieties and the tetrahedral dihydrobis(pyrazol‐1‐yl)borate ligands. 相似文献
29.
Young Joo Kim Pil Ho Huh Byung Kyu Kim 《Journal of Polymer Science.Polymer Physics》2015,53(7):468-474
Supramolecular polyurethane ureas are expected to have superior mechanical properties primarily due to the reversible, noncovalent interactions such as hydrogen bonding interactions. We synthesized polyurethane prepolymers from small molecular weight of poly(tetramethylene ether)glycol and isophorone diisocyanates, which were end capped with propylamine to synthesize polyurethane ureas with high contents of urea and urethane groups for hydrogen‐bonding formations to facilitate self‐healing. The effects of polyurethane urea molecular weight (3000 ≤ Mn ≤ 9000), crosslinking, and cutting direction were studied in terms of thermal, mechanical, and morphological properties with an emphasis on the self‐healing efficiency. It was found that the thermal self‐healability was more pronounced as the molecular weight of polyurethane urea decreased, showing a maximum of more than 96% with 3000 Mn when the sample was cut along the stretch direction. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 468–474 相似文献
30.
Hyun‐Chul Kim Ja‐Min Gu Seong Huh Chul‐Hyun Yo Youngmee Kim 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(10):929-935
Two new one‐dimensional CuII coordination polymers (CPs) containing the C2h‐symmetric terphenyl‐based dicarboxylate linker 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate (3,3′‐TPDC), namely catena‐poly[[bis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ4O,O′:O′′:O′′′] monohydrate], {[Cu(C20H12O4)(C2H7N)2]·H2O}n, (I), and catena‐poly[[aquabis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ2O3:O3′] monohydrate], {[Cu(C20H12O4)(C2H7N)2(H2O)]·H2O}n, (II), were both obtained from two different methods of preparation: one reaction was performed in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential pillar ligand and the other was carried out in the absence of the DABCO pillar. Both reactions afforded crystals of different colours, i.e. violet plates for (I) and blue needles for (II), both of which were analysed by X‐ray crystallography. The 3,3′‐TPDC bridging ligands coordinate the CuII ions in asymmetric chelating modes in (I) and in monodenate binding modes in (II), forming one‐dimensional chains in each case. Both coordination polymers contain two coordinated dimethylamine ligands in mutually trans positions, and there is an additional aqua ligand in (II). The solvent water molecules are involved in hydrogen bonds between the one‐dimensional coordination polymer chains, forming a two‐dimensional network in (I) and a three‐dimensional network in (II). 相似文献