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Komeda S Lutz M Spek AL Yamanaka Y Sato T Chikuma M Reedijk J 《Journal of the American Chemical Society》2002,124(17):4738-4746
The reactions of the dinuclear platinum(II) complexes, [[cis-Pt(NH(3))(2)](2)(mu-OH)(mu-pz)](NO(3))(2) (1, pz = pyrazolate), [[cis-Pt(NH(3))(2)](2)(mu-OH)(mu-1,2,3-ta-N1,N2)](NO(3))(2) (2, 1,2,3-ta = 1,2,3-triazolate), and a newly prepared [[cis-Pt(NH(3))(2)](2)(mu-OH)(mu-4-phe-1,2,3-ta-N1,N2)](NO(3))(2) (3, 4-phe-1,2,3-ta = 4-phenyl-1,2,3-triazolate), whose crystal structure was determined, with 9-ethylguanine (9EtG) have been monitored in aqueous solution at 310 K by means of (1)H NMR spectroscopy. The dinuclear platinum(II) complexes 1-3 each react with 9EtG in a bifunctional way to form 1:2 complexes, [[cis-Pt(NH(3))(2)(9EtG-N7)](2)(mu-pz)](3+) (4), [[cis-Pt(NH(3))(2)(9EtG-N7)](2)(mu-1,2,3-ta-N1,N3)](3+) (5), and [[cis-Pt(NH(3))(2)(9EtG-N7)](2)(mu-4-phe-1,2,3-ta-N1,N3)](3+) (6). The reactions of 2 and 3 involve a novel isomerization, in which the Pt atom, initially bound to N2 on the 1,2,3-ta, migrates to N3 after the first substitution by N7 of 9EtG. This isomerization reaction has been unambiguously characterized by 1D and 2D NMR spectroscopy and pH titration. The reactions of 2 and 3 with 9EtG show faster kinetics, and the second-order rate constants (k) for the reactions of 1-3are 1.57 x 10(-4), 2.53 x 10(-4), and 2.56 x 10(-4) M(-1) s(-1), respectively. The pK(a) values at the N1H site of 9EtG were determined for 4-6 from the pH titration curves. Cytotoxicity assays of 1-3 were performed in L1210 murine leukemia cell lines, respectively sensitive and resistant to cisplatin. In the parent cell line, 2 and 3 exhibit higher cytotoxicity compared to cisplatin, especially, 2 is 10 times as active as cisplatin. 1 was found to be less cytotoxic than cisplatin, but still in the active range and more active than cisplatin in a cisplatin-resistant cell line. 相似文献
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用于高分辨率 PET探测器的LSO闪烁晶体的研究 总被引:6,自引:1,他引:5
LSO晶体具有密度大光输出量强和衰减时间短的特性使其成为在PET探测器领域的应用潜在的闪烁晶体材料.按照辐射成象系统应用的性能要求我们对LSO晶体的闪烁特性进行了评价.为了获取较高的光输出量,研究和验证了许许多多的晶体表面的状况对光输出量的影响.对于单个LSO晶体和R5900-00-C12位敏管相耦合的系统,钠伽马射线源的511keV的能量峰处的能量分辨率为15%,时间分辨率为0.65ns,最后对三个LSO阵列分别成象验证了其空间分辨本领. 相似文献
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T. Nishiyama S. Yasuda T. Inamuro 《The European physical journal. Special topics》2009,171(1):145-149
The deformation and breakup processes of a particle-cluster aggregate under shear flows are investigated by the two-phase
lattice Boltzmann method. In the simulation the particle is modeled by a hard droplet with large viscosity and strong surface
tension. The van der Waals attraction force is taken into account for the interaction between the particles. Also, the Brownian
motion is considered for nano-particles. Two important dimensionless parameters are introduced in order to classify calculated
results. One is the ratio of fluid force to the maximum inter-particle force, Y, and the other is the Péclet number which is the ratio of the rate of diffusion by a shear flow to the rate of diffusion
by Brownian motion. It is found that Y is the key factor in dispersion and that the Brownian motion retards the dispersion. 相似文献
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Motomasa Kobayashi Byeng Wha Son Takaji Fujiwara Yoshimasa Kyogoku Isao Kitagawa 《Tetrahedron letters》1984,25(48):5543-5546
A new diterpene named neodolabelline (5), having a methyl migrated dolabellane-type skeleton, was isolated from the stoloniferan soft coral Clavularia koellikeri, together with clavukerins (trinor-sesquiterpenes) and bicyclo-germacrene, and the absolute configuration was determined. 相似文献
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Fluid flow in a rotating cylindrical container of radius Rw and height H with a co-axially rotating disk of radius Rd at the fluid surface is numerically investigated. The container and the disk rotate with angular velocities Ωw and Ωd, respectively. We solve the axisymmetric Navier-Stokes equations using a finite-volume method. The effects of the relative directions and magnitudes of the disk and container rotations are studied. The calculations are carried out with various ratios of Ωw and Ωd for H/Rw = 2 and Rd/Rw = 0.7. Streamlines and velocity vectors in the meridional plane and azimuthal velocities are obtained. The flow fields in the meridional plane are discussed with relation to azimuthal velocities in the interior of the container. The numerical results are also compared with experimental data. 相似文献
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The lattice Boltzmann method for two-phase fluid flows is applied to the simulations of gas-liquid two-phase flows in a micro
porous structure for various capillary numbers at low Reynolds numbers. The behaviors of the gas-liquid interface and the
velocities of the two-phase fluid in the structure are simulated, and the permeability of gas and liquid through the structure
are estimated from the calculated results. By changing the void fraction, the contact angle of the interface on walls, and
the surface tension, the effect of these properties on the behaviors and the permeability of the two-phase flows in the micro
porous structure is investigated. It is found that the permeability of liquid flows depends on the contact angle and it increases
for hydrophobic walls. It is also seen that liquid flows are choked in pores for large void fractions and low capillary numbers. 相似文献
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