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1.
Increasing the reaction temperature of the living cationic polymerization of isobutylene is crucial for industrial production due to the cost of refrigeration. The reaction temperature increase was achieved with an accelerated reaction rate using a flow reaction system. The polymerization conditions, including the flow reactor design, were based on the results of kinetic studies. Utilizing a milli‐scale flow reactor, polyisobutylene, which has a narrow molecular weight distribution, was obtained within a considerably short residence time at a high temperature. Furthermore, it was confirmed that the value of Mw/Mn correlates with the product of the Reynolds number and the angle of collision. 相似文献
2.
3.
Toshiyuki MasuiTakanobu Chiga Nobuhito Imanaka Gin-ya Adachi 《Materials Research Bulletin》2003,38(1):17-24
Fine particles of a blue emission phosphor Sr2CeO4 have been synthesized using a chemical co-precipitation technique, and the textual and luminescent properties were compared with the one synthesized by the conventional solid-state reaction method. Particle size and distribution of the Sr2CeO4 fine powder prepared by the co-precipitation process were smaller and narrower than those obtained by the samples prepared from the conventional one. The emission intensity of the fine particles was equal to that of the larger particles prepared from the solid-state reaction, on the contrary to the general tendency that emission intensity decrease with particle size reduction. Although no Ce3+ peaks were observed in EPR measurements, X-ray photoelectron spectra of the samples clearly elucidated the existence of Ce3+ only on the surface of Sr2CeO4. 相似文献
4.
Jinting Jiu Seiji Isoda Motonari Adachi Hao Wang 《Journal of Materials Science: Materials in Electronics》2007,18(6):593-597
Nanocrystalline TiO2 with 3–10 nm in diameter was prepared with a surfactant-template method. Dye-sensitized solar cells were assembled using
the prepared nanocrystalline TiO2 with large surface area and high crystallinity, which achieved significant higher Jsc when compared to cells fabricated with
bigger particles of 25 nm in diameter. In the cells with nanocrystalline TiO2, the sintering temperature drastically affected the conversion performance of the cells. 相似文献
5.
Masatsune Kato Takaaki Aoki Takashi Noji Yasuhiro Ono Yoji Koike Tomoyuki Hikita Yoshitami Saito 《Journal of Superconductivity and Novel Magnetism》1994,7(1):37-38
We have investigated the relation between the crystal structure and superconductivity in La1.9Bi0.1CuO4+δ , in which the phase separation observed in La2CuO4+δ is suppressed. A phase diagram in theT?δ plane is given for La1.9Bi0.1CuO4+δ with excess oxygen. For very smallδ values, the crystal structure is orthorhombic, and an orthorhombic-tetragonal phase transition occurs markedly atδ ~ 0.03 in the measured temperature range between 13 and 293 K. Superconductivity is observed in the range of 0.04<δ<0.11. This is clear evidence thathigh-T c superconductivity also appears in the tetragonal phase. 相似文献
6.
Interleukin-5 (IL-5) regulates the growth and function of eosinophils. It induces rapid tyrosine phosphorylation of Lyn and Jak2 tyrosine kinases. The role of tyrosine phosphatases in IL-5 signal transduction has not been investigated. In this study, we provide first evidence that SH2 protein tyrosine phosphatase 2 (SHPTP2) phosphotyrosine phosphatase plays a key role in prevention of eosinophil death by IL-5. We found that IL-5 produced a rapid activation and tyrosine phosphorylation of SHPTP2 within 1 min. The tyrosine phosphorylated SHPTP2 was complexed with the adapter protein Grb2 in IL-5-stimulated eosinophils. Furthermore, SHPTP2 appeared to physically associate with beta common (betac) chain of the IL-5 receptor (IL-5betacR). The association of SHPTP2 with IL-5betacR was reconstituted using a synthetic phosphotyrosine-containing peptide, betac 605-624, encompassing tyrosine (Y)612. The binding to the phosphotyrosine-containing peptide increased the phosphatase activity of SHPTP2, whereas the same peptide with the phosphorylated Y612--> F mutation did not activate SHPTP2. Only SHPTP2 antisense oligonucleotides, but not sense SHPTP2, could inhibit tyrosine phosphorylation of microtubule-associated protein kinase, and reverse the eosinophil survival advantage provided by IL-5. Therefore, we conclude that the physical association of SHPTP2 with the phosphorylated betac receptor and Grb2 and its early activation are required for the coupling of the receptor to the Ras signaling pathway and for prevention of eosinophil death by IL-5. 相似文献
7.
P Trifillis K Adachi T Yamaguchi E Schwartz S Surrey 《Canadian Metallurgical Quarterly》1996,271(43):26931-26938
We previously identified five delta-globin gene alleles associated with reduced hemoglobin (Hb) A2 (Trifillis, P., Ioannou, P., Schwartz, E., and Surrey, S. (1991) Blood 78, 3298-3305). We have now evaluated functional consequences of the changes after expression in COS-1 cells to monitor effects on RNA splicing. In addition, variant Hb A2 tetramers were expressed in yeast to assess effects of amino acid changes on oxygen binding and stability to heat and mechanical agitation. The G --> T change at codon 27 and the A --> G change in IVS-2 both affect RNA splicing, whereas the C --> T change at codon 97 and the AT deletion in IVS-2 have no effect. Oxygen equilibrium curves of the Hb A2 variants expressed in yeast were similar to that of wild type Hb A2. None of the three variant Hb A2 tetramers (Thr --> Ile at codon 4 (Hb deltaT4I), Ala --> Ser at codon 27 (Hb deltaA27S), and Arg --> Cys at codon 116 (Hb deltaR116C)) showed decreased heat stability compared with Hb A2, whereas the Hb deltaT4I variant showed highest instability to mechanical agitation. Co-expression in yeast of alpha-globin chain and the delta-chain variant containing a Leu --> Pro change at codon 141 yielded no identifiable tetramers, suggesting lack of assembly or severe tetramer instability. These studies show the probable cause for decreased Hb A2 for two alleles is due to defective splicing, whereas decreased protein stability, increased tetramer association with red cell membranes, increased interdisulfide bond formation of delta-chains, which inhibits assembly with alpha-chains, and/or reduced assembly is suggested for the other three alleles. 相似文献
8.
K Yoshida Y Takamatsu Y Adachi M Kishi H Sekine T Shigematsu 《Canadian Metallurgical Quarterly》1996,37(2):55-62
Endoglucanase production was measured in culture filtrates of four species of Saccobolus growing in media containing glucose or crystalline cellulose as the only carbon sources. Enzyme activity was four to seven times higher in the presence of cellulose than glucose. S. saccoboloides showed maximal growth and enzyme production. The extracellular proteins secreted during growth on cellulose were separated by polyacrylamide gel electrophoresis and stained for proteins. A zymogram technique was used to visualize bands with endoglucanase activity. The four species showed different protein and isoenzyme patterns. 相似文献
9.
Y Koya T Matsubara T Ikeuchi S Adachi K Yamauchi 《Canadian Metallurgical Quarterly》1997,118(4):1217-1223
Vitellogenin of matrotrophic viviparous eelpout (Zoarces elongatus) was purified from estradiol-17 beta (E2) treated immature male sera by gel chromatography and anion exchange chromatography. Isolated vitellogenin has a molecular weight of 540 kDa estimated by gel chromatography. Serum levels of vitellogenin in females were measured during oocyte development and gestation by single radial immunodiffusion. Serum vitellogenin level was low (less than 0.2 mg/ml) during the early vitellogenic period, increased in the late vitellogenic period to a peak level (6.4 +/- 2.1 mg/ml) at the beginning of gestation. After that it rapidly decreased to a low level (0.1 +/- 0.1 mg/ml) during the early gestation period. Levels of vitellogenin remained low throughout the gestation period. Serum E2 levels in females showed increased from 1.3 to 3.0 ng/ml during the late vitellogenic period, and declined to 0.4 ng/ml during the early gestation period. Serum levels of E2 showed good correlation with serum vitellogenin levels, suggesting that the vitellogenin synthesis is controlled by E2 in this species. These results combined with the matrotrophic growth of embryo during gestation suggest that there is a shift in the synthesis of maternal nutritional products for embryos from the yolk to other nutrients. 相似文献
10.
Phospholipase A2 [EC 3.1.1.4] treatment of pig kidney Na+,K(+)-ATPase [EC 3.6.1.3] labeled with fluorescence probes at the alpha-chain reduced the extent of the fluorescence intensity change of an N-[p-(2-benzimidazolyl)phenyl]maleimide (BIPM) probe at Cys-964 to below one-third of the control level accompanying the accumulation of phosphoenzymes. However, it only induced a slight decrease in that of a fluorescence isothiocyanate (FITC) probe at Lys-501 with a large decrease in the rate of change. The addition of phosphatidylserine (PS) or phosphatidylinositol (PI) to the phospholipase-treated BIPM-FITC-labeled enzyme increased the rate of the FITC fluorescence change. Phospholipase treatment of the BIPM-enzyme greatly reduced the Na+,K(+)-ATPase activity. The addition of PS or PI to the treated enzyme induced reactivation. These data and others suggest that Cys-964 and Glu-953 (Rb+ protectable dicyclohexyl carbodiimide binding site) are located in the vicinity of the surface area of the enzyme where hydrocarbon chains of phospholipids are present, and conserved H-bonding amino acids, Thr-955 and Ser-962, are located rather near the center of a domain forming a cation binding route or cage with other hydrophobic transmembrane segments. These data may indicate that the interaction between the BIPM probe and the hydrocarbon chains of phospholipids changes in such a way as to sense the change in the binding state of various ligands accompanying the sequential appearance of reaction intermediates of the enzyme. 相似文献