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61.
S. Iijima A. Nomura F. Mizukami S. Shin F. Mizutani 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(2):297-302
Spinel iron oxide (Fe3O4-γ-Fe2O3) particles were supported on microbeads of silica gel by the calcination of the silica gel base adsorbing citric acid and Fe3+ ions. The X-ray diffraction patterns and the57Fe Mössbauer spectra measured for the spinel iron oxide indicated that the particle size of the oxide was regulated by the mean pore diameter (4–82 nm) of the silica gel support employed. In the case of α-Fe2O3 particles prepared by using the same silica gel beads, it was revealed by the Mössbauer spectra and the electron micrographs that there were relatively large particles of the oxide on the surface of the beads, in addition to the particles in the silica gel micropores. 相似文献
62.
Tatsuya Nakamura Dr. Hisashi Matsushita Dr. Fuminori Sugihara Prof. Yoshichika Yoshioka Dr. Shin Mizukami Prof. Kazuya Kikuchi 《Angewandte Chemie (International ed. in English)》2015,54(3):1007-1010
19F magnetic resonance imaging (MRI) probes that can detect biological phenomena such as cell dynamics, ion concentrations, and enzymatic activity have attracted significant attention. Although perfluorocarbon (PFC) encapsulated nanoparticles are of interest in molecular imaging owing to their high sensitivity, activatable PFC nanoparticles have not been developed. In this study, we showed for the first time that the paramagnetic relaxation enhancement (PRE) effect can efficiently decrease the 19F NMR/MRI signals of PFCs in silica nanoparticles. On the basis of the PRE effect, we developed a reduction‐responsive PFC‐encapsulated nanoparticle probe, FLAME‐SS‐Gd3+ (FSG). This is the first example of an activatable PFC‐encapsulated nanoparticle that can be used for in vivo imaging. Calculations revealed that the ratio of fluorine atoms to Gd3+ complexes per nanoparticle was more than approximately 5.0×102, resulting in the high signal augmentation. 相似文献
63.
Synthesis of protein-silica hybrid hollow particles through the combination of protein catalysts and sonochemical treatment 总被引:1,自引:0,他引:1
Shiomi T Tsunoda T Kawai A Chiku H Mizukami F Sakaguchi K 《Chemical communications (Cambridge, England)》2005,(42):5325-5327
Hollow spherical particles with protein-silica hybrid shell structures have been synthesized through a combination of the catalytic activity of the protein and sonochemical treatment; the morphologies of the particles were controlled by varying the protein concentration. 相似文献
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65.
We used both localized and periodic calculations on a series of monovalent (Li+, Na+, K+, Rb+, Cs+) and divalent (Mg2+, Ca2+, Sr2+, Ba2+) cations to monitor their effect on the swelling of clays. The activity order obtained for the exchangeable cations among all the monovalent and divalent series studied: Ca2+ > Sr2+ > Mg2+ > Rb+ > Ba2+ > Na+ > Li+ > Cs+ > K+. We have shown that, in case of dioctahedral smectite, the hydroxyl groups play a major role in their interaction with water and other polar molecules in the presence of an interlayer cation. We studied both type of clays, with a different surface structure and with/without water using a periodic calculation. Interlayer cations and charged 2:1 clay surfaces interact strongly with polar solvents; when it is in an aqueous medium, clay expands and the phenomenon is known as crystalline swelling. The extent of swelling is controlled by a balance between relatively strong swelling forces and electrostatic forces of attraction between the negatively charged phyllosilicate layer and the positively charged interlayer cation. We have calculated the solvation energy at the first hydration shell of an exchangeable cation, but the results do not correspond directly to the experimental d-spacing values. A novel quantitative scale is proposed with the numbers generated by the relative nucleophilicity of the active cation sites in their hydrated state through Fukui functions within the helm of the hard soft acid base principle. The solvation effect thus measured show a perfect match with experiment, which proposes that the reactivity index calculation with a first hydration shell could rationalize the swelling mechanism for exchangeable cations. The conformers after electron donation or acceptance propose the swelling mechanism for monovalent and divalent cations. 相似文献
66.
A simple method to synthesize (+/-)-2-O-(4-coumaroyl)-3-(4-hydroxyphenyl)lactic acid (1), a key intermediate in rosmarinic acid biosynthesis in higher plant cells, was established by condensation of protected 4-coumaric acid and (+/-)-3-(4-hydroxyphenyl)lactic acid followed by deprotection. A stable supply of 1 thus attained will lead to biochemical and molecular biological characterization of later steps of rosmarinic acid biosynthesis. 相似文献
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68.
Associate Professor W. Liu Dr. S. W. Peng Professor K. Mizukami 《Heat and Mass Transfer》1995,31(1-2):49-55
The present paper develops a general mathematical model with some improvements in mass, momentum and energy equations, which introduce more transport mechanisms to simulate simultaneous transfer of heat and mass in the porous media unsaturated with liquid. Numerical calculation results in two-dimension are obtained for the vertical packed bed with its right opening surface exposing to atmospherical environment. The calculating data can demonstrate the cooling effect of the water evaporation for the bed if it is used as a cooling wall of building for room air-conditioning in the hot and dry climate. 相似文献
69.
Multifunctional Core–Shell Silica Nanoparticles for Highly Sensitive 19F Magnetic Resonance Imaging
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Hisashi Matsushita Dr. Shin Mizukami Dr. Fuminori Sugihara Yosuke Nakanishi Prof. Yoshichika Yoshioka Prof. Kazuya Kikuchi 《Angewandte Chemie (International ed. in English)》2014,53(4):1008-1011
19F magnetic resonance imaging (19F MRI) is useful for monitoring particular signals from biological samples, cells, and target tissues, because background signals are missing in animal bodies. Therefore, highly sensitive 19F MRI contrast agents are in great demand for their practical applications. However, we have faced the following challenges: 1) increasing the number of fluorine atoms decreases the solubility of the molecular probes, and 2) the restriction of the molecular mobility attenuates the 19F MRI signals. Herein, we developed novel multifunctional core–shell nanoparticles to solve these issues. They are composed of a core micelle filled with liquid perfluorocarbon and a robust silica shell. These core–shell nanoparticles have superior properties such as high sensitivity, modifiability of the surface, biocompatibility, and sufficient in vivo stability. By the adequate surface modifications, gene expression in living cells and tumor tissue in living mice were successfully detected by 19F MRI. 相似文献
70.
Akira Mizukami 《国际流体数值方法杂志》1985,5(3):281-292
In this paper a fully explicit finite element method (FEFEM) is presented for solving steady incompressible viscous flow problems. This full explicitness is achieved by combining the multiplier (or augmented Lagrangian) method with a pseudo-time-iteration method. FEFEM needs no global matrix at all and is of great advantage to large-scale problems because they can be solved within the limit of core memory. The optimum choice of a time increment and a penalty parameter is discussed and the driven cavity flow at a Reynolds number of 1000 is computed with a refined mesh (60 × 60 elements). 相似文献