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71.
72.
We revealed that in ATX-S10.Na(II)(13,17-bis (1-carboxypropionyl) carbamoylethyl-8-etheny-2-hydroxy-3-hydroxyiminoethylidene-2,7,12,18-tetraethyl porphyrin sodium)-mediated photodynamic therapy using 667 nm nanosecond-pulsed light excitation at a peak intensity of 2.0 MW/cm(2), phototoxicity increased with decreasing pulse repetition rate in the range of 5-30 Hz for A549 cell cultures. To examine the relation between the reaction mechanism and measured phototoxicity, we carefully measured the kinetics of photochemical oxygen consumption and photobleaching during irradiation of ATX-S10.Na(II)-sensitized A549 monolayer cultures. Measurements of oxygen consumption with a microelectrode, which was performed just above the cells, showed that there was no significant difference between the magnitudes of decrease in oxygen at the three repetition rates at the same cumulative fluence. Loss of ATX-S10.Na(II) fluorescence intensity also exhibited little repetition rate dependence when compared at the same cumulative fluence. We investigated the correlation between oxygen consumption and photobleaching during irradiation and obtained "fluorescence-oxygen diagrams." The diagrams showed dynamic changes between oxygen-dependent and oxygen-independent photobleaching at the higher repetition rates of 10 and 30 Hz, whereas such change was not clearly seen over the whole irradiation time at 5 Hz. These results suggest that the reduced phototoxicity at high repetition rates might be due to an oxygen-independent reaction. We presumed that the change in the reaction mechanism was associated with the local concentrations of the photosensitizer and oxygen in cells during irradiation. 相似文献
73.
Imai M Sakai K Kikuchi M Nakaya K Saeki A Teramoto T 《The Journal of chemical physics》2005,122(21):214906
We have investigated the structural development during order-order transitions to the double-gyroid (DG) phase of nonionic surfactant/water systems based on two-dimensional small-angle x-ray scattering patterns from highly oriented ordered mesophases. The lamellar (L) to DG transition proceeds through two intermediate structures, a fluctuating perforated layer structure having ABAB stacking and a hexagonal perforated lamellar structure with ABCABC stacking (HPLABC). For a hexagonally packed cylinder (H) to DG transition, we also observed the HPLABC structure as the intermediate phase, thus the HPLABC is an entrance structure for the DG phase. The hexagonal perforated lamellar (HPL) structure consists of hexagonally packed holes surrounded by the planar tripods, and the transition from HPL structure to the DG phase proceeds by rotation of the dihedral angle of connected tripods. A geometrical consideration shows that large deformations of HPL planes are necessary to form the DG structure from the HPLABC structure, whereas the transition from a HPL structure with ABAB stacking (HPLAB) to the DG structure is straightforward. In spite of the topological constraints, the HPLABC structure is observed in the kinetic pathway to the DG structure. 相似文献
74.
Four new iridoid glycosides, named L-phenylalaninosecologanin (1), 7-O-(4-beta-D-glucopyranosyloxy-3-methoxybenzoyl)secologanolic acid (2), 6'-O-(7alpha-hydroxyswerosyloxy)loganin (3) and (Z)-aldosecologanin (5), were isolated, together with a known one, newly named (E)-aldosecologanin (4), from the stems and leaves of Lonicera japonica. Their structures were established on the basis of chemical and spectral data. 相似文献
75.
Katsuhiko Ono Kyohei Yoshikawa Hiroyuki Yamaguchi Masaaki Tomura Katsuhiro Saito 《Tetrahedron》2007,63(38):9354-9358
BF2 complexes with 1,3-diketone ligands were synthesized, and their optical and electrochemical properties were studied. The colors of the complexes varied depending on the structures of the 1,3-diketone ligands. The absorption and emission maxima of the complexes with 1,3-diaryl-1,3-diketone ligands were considerably red shifted as compared to those of the complexes with 1-aryl-3-trifluoromethyl-1,3-diketone ligands, suggesting an extended π-conjugation of the 1,3-diaryl-1,3-diketone moieties. The molar absorption coefficients and quantum yields of the complexes with 1,3-diaryl-1,3-diketone ligands were larger than those of the complexes with 1-aryl-3-trifluoromethyl-1,3-diketone ligands. Cyclic voltammetry measurements revealed that the reduction potentials of the BF2 complexes were higher than those of the free ligands. These complexes exhibited various emission colors in the solid states due to the intermolecular interactions. 相似文献
76.
The aerial parts of Erigeron annuus (L.) PERS., E. philadelphicus L. and E. sumatrensis RETZ. (Compositae) have been investigated chemically. A new sesquiterpenoid, 6beta,14-epoxyeudesm-4(15)-en-1beta-ol (1), and a new diterpenoid, philadelphinone (6), have been isolated from E. philadelphicus. Four new sesquiterpenoids, (7R*)-opposit-4(15)-ene-1beta,7-diol (2), 11-methoxyopposit-4(15)-en-1beta-ol (3), 15-methoxyisodauc-3-ene-1beta,5alpha-diol (4) and 10alpha-hydroxycadin-4-en-15-al (5), have been isolated from E. annuus. Compounds 2 and 4 were also isolated from E. sumatrensis. The structures of the new compounds were elucidated on the basis of their spectral data. 相似文献
77.
Biomimetic formation of gramicidin S by dimerization-cyclization of pentapeptide precursor on solid support 总被引:1,自引:0,他引:1
The biomimetic formation of gramicidin S, cyclo(-d-Phe-Pro-Val-Orn-Leu-)2, by the dimerization and cyclization of pentapeptide precursor without the protection of δ-amino group of the Orn residue was examined on a solid support. The cyclization of H-d-Phe-Pro-Val-Orn-Leu-oxime on a resin with an oxime group of 0.62 mmol/g in 1,4-dioxane directly gave gramicidin S in a 50% yield. The dimerization-cyclization mode on the solid support was similar to that of the biosynthesis of gramicidin S on an enzyme. 相似文献
78.
Hiroyoshi Nakajima Katsuhiro Yamada Yuki Iseki Satoru Hosoda Ayako Hanai Yasunori Oumi Toshiharu Teranishi Tsuneji Sano 《Journal of polymer science. Part A, Polymer chemistry》2003,41(24):3324-3332
Polypropylene (PP)/Ti-MCM-41 nanocomposites were prepared by isospecific propylene polymerization with Ti-MCM-41/Al(i-C4H9)3 catalyst. The cross polarization/magic angle spinning (CP/MAS) 13C NMR spectrum of the composite was similar to that of the conventional isotactic PP, and the decrease in the pore volume of Ti-MCM-41 in the nanocomposites, as measured by N2 adsorption, was consistent with the value calculated from the weight loss in the thermogravimetric analysis (TGA) curve; both these facts attest to propylene polymerization within the mesopores of Ti-MCM-41. Alkali treatment followed by extraction with o-dichlorobenzene allows us to extract the confined PP out of the Ti-MCM-41 mesopores. Although the PP/Ti-MCM-41 nanocomposites do not exhibit a crystalline melting point, the same PP when extracted from the mesopores showed a clear melting point at 154.7 °C; this indicates that the crystallization of PP confined in mesopores is strongly hindered. For the PP polymerized within the confinement, the molecular weight (Mw) and molecular weight distribution (Mw/Mn) were 84,000 and 4.3, respectively; these values were considerably smaller than those of the PP polymerized concurrently outside the Ti-MCM-41 mesopores (Mw = 200,000–450,000, Mw/Mn = 40–75). Therefore, the confinement also has a marked effect on the molecular weight of the PP. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3324–3332, 2003 相似文献
79.
Belik AA Azuma M Matsuo A Whangbo MH Koo HJ Kikuchi J Kaji T Okubo S Ohta H Kindo K Takano M 《Inorganic chemistry》2005,44(19):6632-6640
SrCu2(PO4)2 was prepared by the solid-state method at 1153 K. Its structure was solved by direct methods in the space group Pccn (No. 56) with Z = 8 from synchrotron X-ray powder diffraction data measured at room temperature. Structure parameters were then refined by the Rietveld method to obtain the lattice parameters, a = 7.94217(8) A, b = 15.36918(14) A, and c = 10.37036(10) A. SrCu2(PO4)2 presents a new structure type and is built up from Sr2O16 and Cu1Cu2O8 units with Cu1...Cu2 = 3.256 A. The magnetic properties of SrCu2(PO4)2 were investigated by magnetic susceptibility, magnetization up to 65 T, Cu nuclear quadrupole resonance (NQR), electron-spin resonance, and specific heat measurements. With spin-dimer analysis, it was shown that the two strongest spin-exchange interactions between Cu sites result from the Cu1-O...O-Cu2 and Cu2-O...O-Cu2 super-superexchange paths with Cu1...Cu2 = 5.861 A and Cu2...Cu2 = 5.251 A, and the superexchange associated with the structural dimer Cu1Cu2O8 is negligible. The magnetic susceptibility data were analyzed in terms of a linear four-spin cluster model, Cu1-Cu2-Cu2-Cu1 with -2J(1)/kB = 82.4 K for Cu1-Cu2 and -2J(2)/k(B) = 59 K for Cu2-Cu2. A spin gap deduced from this model (Delta/kB = 63 K) is in agreement with that obtained from the Cu NQR data (Delta/kB = 65 K). A one-half magnetization plateau was observed between approximately 50 and 63 T at 1.3 K. Specific heat data show that SrCu2(PO4)2 does not undergo a long-range magnetic ordering down to 0.45 K. SrCu2(PO4)2 melts incongruently at 1189 K. We also report its vibrational properties studied with Raman spectroscopy. 相似文献
80.
Noboru Kikuchi 《Numerische Mathematik》1981,37(1):105-120
Summary This study establishes an error estimate for a penalty-finite element approximation of the variational inequality obtained by a class of obstacle problems. By special identification of the penalty term, we first show that the penalty solution converges to the solution of a mixed formulation of the variational inequality. The rate of convergence of the penalization is where is the penalty parameter. To obtain the error of finite element approximation, we apply the results obtained by Brezzi, Hager and Raviart for the mixed finite element method to the variational inequality. 相似文献