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11.
Tsutomu Kagiya Shizuo Narisawa Taizo Ichida Kenichi Fukui Hisao Yokota Masatsune Kondo 《Journal of polymer science. Part A, Polymer chemistry》1966,4(2):293-299
The copolymerization of carbon monoxide and aziridines such as ethylenimine and propylenimine was carried out by γ-ray irradiation. Aziridines and carbon monoxide were allowed to copolymerize under γ-ray irradiation from a Co60 source and gave a crystalline solid copolymer. The yield of the copolymer increased with reaction temperature. The composition of copolymers obtained did not depend on the feed ratio of monomers and was found to be almost equimolar. The copolymer of ethylenimine and carbon monoxide melted at about 322–335°C. with decomposition and has an infrared spectrum identical with that of poly-β-alanine obtained by the hydrogen-migration polymerization of acrylamide. The hydrolyzed product of the ethylenimine–carbon monoxide copolymer was confirmed to be β-alanine by paper chromatography. These results lead to the conclusion that the copolymerization of aziridines and carbon monoxide took place alternatively by γ-ray irradiation, and produced crystalline poly-β-alanines. 相似文献
12.
Akiko Sekihara Hidekazu Honma Tadahiro Fukuju Kiminori Maeda Hisao Murai 《Research on Chemical Intermediates》1998,24(8):859-877
Photooxidation (charge transfer) reactions of carbazole derivatives by maleic anhydride (MA) in alcoholic media are studied
by a time-resolved cw-ESR (TRESR) and Fourier transform ESR (FTESR) techniques. The CIDEP spectra observed in the systems
(methyl-, ethyl-, and phenyl-substituted carbazoles with MA) remarkably depend on the MA concentration. Under the high concentration
conditions, an emissive TM (triplet mechanism) polarization with a slight A/E (absorption/emission) pattern of the RPM (radical
pair mechanism) is observed. In the low concentration of MA, a TM-like absorptive polarization is superimposed on the A/E
pattern of the RPM. Since this reaction takes place exclusively through the triplet state, this spectral phase reveals that
the singlet state of the radical-ion pair (RIP) has an energy higher than that of the triplet state, in other words, the sign
of the apparent exchange interaction of the present RIP systems is positive. The total absorptive polarization observed in
the low concentration of MA is tentatively explained by the polarization transfer from the excited triplet state of carbazoles
in thermal equilibrium. 相似文献
13.
Ia specificities 22 and 23 were found to be determinants on hybrid Ia molecules, formed by the noncovalent binding of a 26,000--28,000 dalton beta polypeptide chain (Ae) coded by the I-A subregion and a 32,000--35,000 dalton alpha chain (E alpha) coded by the I-E subregion. For expression of Ia.23 the Ae chain, coded by the I-A subregion, must be derived from the H-2d haplotype, while Ab, As, or Ak can provide the complementing beta chain for the expression of Ia.22. For expression of Ia.22 and Ia.23, most Ia.7 positive strains can provide the complementing alpha chain (E alpha), with the one exception of B10.PL (Eu), which is Ia.7 positive but will not complement with Ad to express Ia.23. Antisera were also produced against hybrid Ia antigens by immunizing with F1 cells expressing Ia.22 or Ia.23 generated by generated by trans-complementation. These antisera detect the same specificities as conventional anti-Ia.22 and anti-Ia.23 sera produced against cis-complementing Ia antigens. It is postulated that hybrid Ia determinants are involved in recognition and generation of immune response to antigens under dual Ir gene control. It is also suggested that there are 2 types of Ia specificities: 1) allotypic Ia specificities expressed on the alpha or beta chains (for example, Ia.7 on the E alpha chain) and 2) hybrid Ia specificities, which are unique interaction determinants formed by the association of alpha and beta chains (for example, Ia.22 and Ia.23). These interaction gene products may be involved in antigen recognition and presentation. 相似文献
14.
Tsutomu Takeichi Nobuyuki Takahashi Rikio Yokota 《Journal of polymer science. Part A, Polymer chemistry》1994,32(1):167-174
Polyimide/polyimide molecular composite (MC) films comprised of a rigid polyimide derived from biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) and a flexible polyimide derived from BPDA and bis (3,3'-diaminodiphenyl) acetylene (intA) and/or oxydianiline (ODA) were prepared by blending the polyamic acid solutions in 7 : 3 weight ratio, and then imidizing the blend films. Acetylene content in the flexible polyimide backbone was controlled by the ratio of intA and ODA. Cold-drawing of the blend polyamic acid films, followed by imidization, gives high modulus polyimide/polyimide MC films. The modulus of the MC films increased almost linearly with the draw ratio, reaching 25.5 GPa for the 40% drawn film. Acetylene groups in the flexible polyimide can be thermally cured to crosslink. The onset of exotherm appeared at 340°C on DSC, reaching maximum at 398°C. After the thermal crosslinking, the MC films maintained the high modulus, though elongation became small. Taking advantage of the crosslinkable acetylene units, two MC films were laminated and processed at 400°C for 20 min under 100 kg/cm2 to give a good-quality laminate film. The interface of the two films was strongly bonded through the crosslinking of acetylene groups. Laminate films maintained the high modulus afforded by the cold-drawing. © 1994 John Wiley & Sons, Inc. 相似文献
15.
Chemical ionization (CI) and fast atom bombardment (FAB) mass spectra of simple bifunctional aromatic compounds were compared. Some significant differences were revealed with respect to the site of protonation and extent of fragmentations. Unlike conventional CI ionization, the protonated molecule formation by FAB could not be accounted for by ordinary proton transfer reactions in the gas phase. The observed ions under FAB conditions appear to be regulated by proton exchange reactions through frequent collisions in some particular region between the matrix and the gas phase. 相似文献
16.
Akihiko Sugie Hiromi Shimomura Junki Katsube Hisao Yamamoto 《Tetrahedron letters》1979,20(28):2607-2610
A stable PGI2 analog (methanoprostacyclin ) was synthesized starting from 5-norbornene-2,3-dicarboxylic anhydride. 相似文献
17.
The equations for a barotropic viscous gas in one space dimensiondν=(μ(?νε)ε?p ε)dt+dG,? t +?2νε=0,p=?γ with a perturbationdG are considered under the assumption thatG is only a function of bounded variation inL 2(Θ) orH 0 1 (Θ) (Θ=]0, α[) and the esistence and the uniqueness of the global solution in a class of solutions of «strong type» as well as in a class of solutions of «weak type» are proved. This result constitutes a generalization of the result of Kazhikhov [8] and that of Shelukhin [10] and contains preliminary considerations for the corrisponding stochastic equations. 相似文献
18.
Kondo F Saito H Hayashi R Onda H Kobayashi S Matsumoto M Suzuki M Ito Y Oka H Nakanishi T Shimizu A 《The Analyst》2003,128(11):1360-1364
We developed a rapid and reliable identification method for Shiga toxins in Shiga toxin-producing Escherichia coli (STEC) using immunoprecipitation and high-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS). Polyclonal antisera specific for Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2) were raised in rabbits so as to be used for the immunoprecipitation. The immunoprecipitaion was carried out by mixing sample solutions with 50 microl each of the antisera to Stx1 and Stx2 followed by allowing the mixed solutions to stand for 30 min. The quantity required to obtain the immunoprecipitate was more than 0.5 microg of Shiga toxins. HPLC-ESI-MS analysis of the resulting immunoprecipitates provided accurate molecular weight information on Shiga toxins, leading to direct evidence for the presence of these toxins. It requires at most two days to perform our procedure from toxin extraction to measurement of HPLC-ESI-MS whereas the previous method using isolation procedures required about two weeks to complete. The usefulness of the present method has been demonstrated by identifying Stx1, Stx2 and a variant of Stx2 (Stx2e) in the immunoprecipitates prepared from STEC strains. 相似文献
19.
Carbazoledioxazines with an angular type structure (5,15-dialkyl-7,17-dialkyloxy-9,19-dichloro-5,15-dihydrodiindolo[2,3-c:2′,3′-n]triphenodioxazines) were selectively synthesized by electrochemical oxidative ring closure of precursors (2,5-bis(9-alkyl-2-alkyloxy-3-carbazolylamino)-3,6-dichloro-1,4-benzoquinones). The structure was confirmed by 1H-nmr and other instrumental analyses. Their thermal properties and solubilities were investigated and were compared with those of carbazoledioxazines with a linear type structure. 相似文献
20.
Certain amides and thioamides can easily be methylated with diazomethane in the presence of silica gel. 相似文献