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排序方式: 共有468条查询结果,搜索用时 15 毫秒
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Takeo Hattori Atsushi Shigemori Jun-Ichi Mohri Masahiro Yoshimura Shigeyuki Somiya 《Journal of the American Ceramic Society》1982,65(9):c142-c142
Powder compacts of synthetic mica (fluorphlogopite) encapsulated in a boro–silicate glass tube were isostatically hot–pressed in a Roy–Tuttle–type pressure vessel. Synthetic mica was sintered to a density of 2.60 g/cm3 (91.2% of theoretical density) without additives under 98 MPa of water at 800°C for 45 min. 相似文献
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Noriaki Takagi Yoshinobu Izumi Kimiko Ema Tadashi Yamamoto Kazushige Nishizawa 《溶剂提取与离子交换》2013,31(6):1461-1471
ABSTRACT Dicyclohexano- 18-crown-6 (DC18C6), dissolved in chloroform, 1-octanol, toluene or cyclohexane, was irradiated by 60Co γ-rays. Radiolytic destruction of DC18C6, measured by gas chromatography, decreased in the order: chloroform > cyclohexane > 1-octanol > toluene. Distribution coefficients in the solvent extraction of strontium from nitric acid solution were measured. These distribution coefficients were minimally affected by γ-irradiation in toluene solution, but decreased with the absorbed dose in chloroform solution. It was suggested that the distribution coefficient for the liquid-liquid extraction system was influenced by radiolytic products. The effect of radiolytic products on the distribution coefficients was evaluated by considering DC18C6 remaining in the organic phase after irradiation. The distribution coefficient measured for the organic phase with radiolytic products was larger than that without radiolytic products. The radiolytic products were thus shown to contribute to the increase in the distribution coefficient. 相似文献
15.
Kinetically Stable Bicelles with Dilution Tolerance,Size Tunability,and Thermoresponsiveness for Drug Delivery Applications 下载免费PDF全文
Dr. Noriyuki Uchida Dr. Noriko Nishizawa Horimoto Kuniyo Yamada Dr. Takaaki Hikima Dr. Yasuhiro Ishida 《Chembiochem : a European journal of chemical biology》2018,19(18):1922-1926
Mixtures of a phospholipid (1,2‐dipalmitoyl‐sn‐glycero‐3‐phosphatidylcholine, DPPC) and a sodium‐cholate‐derived surfactant (SC‐C5) at room temperature formed phospholipid bilayer fragments that were edge‐stabilized by SC‐C5: so‐called “bicelles”. Because the bilayer melting point of DPPC (41 °C) is above room temperature and because SC‐C5 has an exceptionally low critical micelle concentration (<0.5 mm ), the bicelles are kinetically frozen at room temperature. Consequently, they exist even when the mixture is diluted to a concentration of 0.04 wt %. In addition, the lateral size of the bicelles can be fine‐tuned by altering the molar ratio of DPPC to SC‐C5. On heating to ≈37 °C, the bicelles transformed into micelles composed of DPPC and SC‐C5. By taking advantage of the dilution tolerance, size tunability, and thermoresponsiveness, we demonstrated in vitro drug delivery based on use of the bicelles as carriers, which suggests their potential utility in transdermal drug delivery. 相似文献
16.
Sudo J Iwase H Higashiyama K Kakuno K Miyasaka F Meguro T Takayama K 《Drug development and industrial pharmacy》2002,28(1):59-65
To increase delivery of L-dopa in its transdermal absorption, a new lipophilic derivative of L-dopa, L-dopa-butylester, was synthesized. An in-vitro study employing two-chamber diffusion cells, in which the excised rat abdominal skin was mounted, revealed that, in the presence of L-menthol and ethanol, L-dopa-butylester penetrated in its original form more effectively than L-dopa. L-Dopa-butylester sheets were made by immersing wiper sheets in methanol containing the compound, and then evaporating the methanol. An extraction study of the compound from the sheets revealed that its stability was maintained for at least 12 weeks. In an in-vivo cutaneous absorption study, an L-dopa-butylester sheet was attached to the shaved rat abdominal skin. A hydrogel containing L-menthol and ethanol was spread on vinyl tape, and this sheet was placed over it. In plasma, the L-dopa level rose linearly between 30 and 180 min after the cutaneous application; L-dopa-butylester was not detected. The L-dopa level was higher than that in which L-dopa was applied. These findings indicated that the lipophilic nature of L-dopa-butylester further increased its penetration through the skin, and that L-dopa-butylester that was taken up into the general circulation system was rapidly converted to L-dopa by hydrolysis in the body. 相似文献
17.
Counter-selections for the loss of introduced plasmid sequences are useful for gene manipulations in yeast. We have used GAL10 promoter-mediated overexpression of GIN sequences, which inhibit the growth of cells, to develop a novel counter-selection system. Yeast cells carrying a GIN sequence grow normally on glucose medium but are unable to grow on galactose medium, whereas derivatives that have lost the GIN sequence are able to grow in the presence of galactose. We constructed autonomously replicating, integrating, and disruption plasmids carrying GIN sequences and tested their use to select for loss of the plasmid. The results showed that the GIN sequences provide a selection for efficient loss of plasmids or integrated constructs from yeast during growth on galactose medium, indicating that this system can be used for plasmid shuffling, gene replacements and marker gene recycling. This counter-selection system has wide application, because any Gal+ strain and a wide variety of marker genes can be used. In addition, counter-selection systems using growth-inhibitory sequences should be applicable to other yeasts and possibly to other organisms. 相似文献
18.
K. Nishizawa H. Kato K. Mimori T. Yoshida N. Hasegawa M. Tsuji Y. Tamaura 《Journal of Materials Science》1994,29(3):768-772
Methanation reactivity was studied for the surface carbon deposited from CO2 on the surface of Rh-bearing activated magnetite. The most active material (Rh=0.83 wt %) for methanation was prepared by the impregnation method at 60°C and showed 98% conversion at 300°C. The surface carbon was composed of elemental carbon (-carbon) and polymerized carbon (-carbon), the proportion being dependent on the density of carbon deposited. In temperature-programmed surface reaction, the extent of conversion of the - and -carbon to CH4 was 0.34 (-carbon) and 0.53 (-carbon), respectively, and the total conversion was 0.87. This result indicates that not only elemental carbon but polymerized carbon (-carbon) could be converted to CH4 on the Rh-bearing activated (-carbon) magnetite, whereas -carbon is not hydrogenated on activated magnetite. 相似文献
19.
Yukito Murakami Jun-Ichi Kikuchi Kazunari Akiyoshi Nobuyuki Shiratori 《Israel journal of chemistry》1987,28(1):23-28
The transamination reaction of l-phenylalanine with pyruvate as catalyzed by the artificial transaminase formed with synthetic bilayer aggregates was examined in aqueous media under mild kinetic conditions. Each catalyst system was constructed with a combination of a synthetic peptide lipid, a hydrophobic vitamin B6 derivative, and metal ions. Modification of the active site in the present artificial transaminase was performed by changing a combination of molecular components constituting the catalytic system. While the catalytic activity was scarcely influenced by differences in aggregate structure, single- or multi-walled bilayer, and in copper-(II) concentration, molecular structures of the hydrophobic vitamin B6 and an amino acid residue of the peptide lipid had significant effects on the reactivity. 相似文献
20.
A novel cross-correlation measurement system without mechanical action has been demonstrated in which the delay time between the reference and signal pulse can be electronically scanned by utilising the soliton self-frequency shift and the chromatic dispersion in the optical fibre. In this system, the reference pulse is the ideal femtosecond soliton pulse. The scanning range, the resolution and the scanning speed of the delay time can be arbitrarily changed only by the electronic control 相似文献