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91.
A facile method for the construction of an immunoconjugate which displays targeting ligands, such as antibody fragments, with a high density is reported. For this purpose, we synthesized a novel trifunctional crosslinking reagent. By the use of this reagent, ligands targeting the specific cell can be displayed on the surface of the drug carrier with a high density. In this study, we display HER2 (human epidermal growth‐factor receptor‐2) binding ligands on branched polyethylenimine (PEI), which can form polyplexes with plasmid DNA. Kinetic analysis of the binding to the extracellular domain of HER2 show the PEI displaying a high density of ligands binds to the target more strongly compared to the PEI displaying ligands at a low density. The increased density of HER2 ligands displayed on the gene carrier contributes to the improved transfection efficiency. This approach can be applied to other drug delivery systems, including liposome, micelle, and so on. 相似文献
92.
The reaction between glass-like carbon (GC) and chlorine trifluoride (ClF3) gas was investigated with weight measurements, surface analysis, and gas desorption measurements, where the ClF3 gas is used for the in situ cleaning of tubes in silicon-related fabrication equipment. From Auger electron spectroscopy and X-ray photoelectron spectroscopy measurements, a carbon mono-fluoride, –(CF)n–, film near the surface of GC is considered to be grown onto the GC surface above 400 °C by the chemical reaction with ClF3, and this thickness of the fluoride film depends on the temperature. The grown fluoride film desorbs by annealing in a vacuum up to 600 °C. Although GC is apparently etched by ClF3 over 600 °C, the etch rate of GC is much lower than that of SiC and quartz. 相似文献
93.
Metal-ion complexation of 7-benzylimidazo[1,2-a]pyrazin-3(7H)-one derivative (2) with Li+, Mg2+, Ca2+, Ba2+, Sc3+, and La3+ in acetonitrile resulted in successive modulations of its UV/vis absorption and fluorescence spectroscopic properties. This result indicates that 2 can be used as a colorimetric and fluorometric sensor of the Lewis acidity of a metal ion in aprotic solutions. The hypothesis that the metal-ion complex has a O10(imidazopyrazinone)-metal ion bond was supported by X-ray crystallographic analysis and quantum chemical calculations for a Li+ complex of 7-methylimidazo[1,2-a]pyrazin-3(7H)-one derivative (1). 相似文献
94.
Arthur G. Maki 《Journal of Molecular Spectroscopy》2011,269(2):166-174
The high-resolution spectrum of cyanogen (14N12C12C14N) has been measured from 500 to 4900 cm−1. For this isotopomer many combination levels with both degenerate fundamentals, ν4 and ν5, have been measured for the first time and the effects of vibrational l-type resonance are observed as well as rotational l-type resonance. The effects of the vibrational resonance coupling ν2 and 2ν4 have also been studied. The data have been combined with earlier measurements below 500 cm−1 to give a comprehensive catalog of the vibrational energy levels and the rovibrational constants for the normal isotopomer of cyanogen. A comparison of the term value constants for the three major symmetric isotopomers is given and they are compared with a recent ab initio calculation. The present data were combined with earlier work on the two symmetric isotopomers, 13C214N2 and 12C215N2, to obtain the equilibrium bond lengths, rCC = 138.109(60) pm and rCN = 115.976(40) pm. 相似文献
95.
I. Tsukada M. Hanawa Seiki Komiya A. Ichinose T. Akiike Y. Imai A. Maeda 《Physica C: Superconductivity and its Applications》2011,471(21-22):625-629
The Hall effect is investigated in thin-film samples of iron–chalcogenide superconductors in detail. The Hall coefficient (RH) of FeTe and Fe(Se1–xTex) exhibits a similar positive value around 300 K, indicating that the high-temperature normal state is dominated by hole-channel transport. FeTe exhibits a sign reversal from positive to negative across the transition to the low-temperature antiferromagnetic state, indicating the occurrence of drastic reconstruction in the band structure. The mobility analysis using the carrier density theoretically calculated reveals that the mobility of holes is strongly suppressed to zero, and hence the electric transport looks to be dominated by electrons. The Se substitution to Te suppresses the antiferromagnetic long-range order and induces superconductivity instead. The similar mobility analysis for Fe(Se0.4Te0.6) and Fe(Se0.5Te0.5) thin films shows that the mobility of electrons increases with decreasing temperature even in the paramagnetic state, and keeps sufficiently high values down to the superconducting transition temperature. From the comparison between FeTe and Fe(Se1–xTex), it is suggested that the coexistence of ‘itinerant’ carriers both in electron and hole channels is indispensable for the occurrence of superconductivity. 相似文献
96.
We derive time dependent Ginzburg-Landau equations for strong coupling superconductors. It is shown that due to a certain separability of the order parameter the equation for it’s time dependent fluctuations is again of diffusion type. Strong coupling effects show up only in the numerical coefficients of the diffusion equation. We apply our findings to the problem of electrical resistivity in strong coupling superconducting materials above the transition temperatureT c. 相似文献
97.
98.
d-wave superconductor as a model of high-Tc superconductors 总被引:1,自引:0,他引:1
99.
Ohyama K Oyamada K Kishikawa N Ohba Y Wada M Maki T Nakashima K Kuroda N 《Journal of chromatography. A》2008,1208(1-2):242-245
Three new chiral stationary phases with different lengths of l-phenylalanine peptide were prepared by solid-phase synthesis with tert-butoxycarbonyl (Boc)-l-phenylalanine on silica. The effect of phenylalanine peptide length on enantioselectivity was studied. The best separation of R/S-warfarin was achieved by the chiral stationary phase with intermediate peptide length. These stationary phases were found to exist mainly in alpha-helical conformation by using FT-IR spectra. The end-capping reagents for the N-terminus of the peptide were also evaluated. 相似文献
100.
Fujimori I Mita T Maki K Shiro M Sato A Furusho S Kanai M Shibasaki M 《Journal of the American Chemical Society》2006,128(51):16438-16439
New chiral ligands for asymmetric polymetallic catalysts were designed on the basis of the assumption that the higher-order assembly structure is stabilized by modifying the modular unit. The designed ligands 6 and 7 contained a scaffolding cyclohexane ring with a Lewis base phosphine oxide directly attached to the scaffold. A module in the polymetallic complex contains two metals per ligand, and a stable 6-, 5-, 5-membered fused chelation ring system should be generated. Synthesis of these ligands is simple and high yielding, using a catalytic dynamic kinetic resolution promoted by the Trost catalyst as a key step. Ligand function was assessed in a catalytic asymmetric ring-opening reaction of meso-aziridines with TMSCN, a useful reaction for the synthesis of optically active beta-amino acids. The Gd complex generated from Gd(OiPr)3 and the ligand was a highly active and enantioselective catalyst in this reaction. Enantioselectivity was reversed compared to the previously reported d-glucose-derived catalyst containing the same chirality of the individual module. ESI-MS analysis and X-ray crystallographic studies indicate that the assembly state of the modules in the polymetallic catalysts differs depending on the chiral ligand. The difference in the higher-order structure stems from a subtle change (one carbon) in the position of the Lewis base relative to the Gd metal. The change in the higher-order structure of the polymetallic complex led to a dramatic reversal of the enantioselectivity and increased catalyst activity. 相似文献