共查询到20条相似文献,搜索用时 0 毫秒
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DaZhiLI XinYaHE HuiWANG LiSUN BingChengLIN 《中国化学快报》2004,15(9):1079-1082
The interactions between amnesic red-tide toxin, domoic acid (DA) and 14mer double-stranded DNA (dsDNA with three kinds of sequences) were studied by capillary zone electrophoresis (CZE). For the dsDNA with a sequence of 5‘-CCCCCTATACCCGC-3‘, the amount of free dsDNA decreases with the increase of added DA, and the signal of DA-dsDNA complex was observed. Meanwhile, the other two dsDNAs, 5‘-(C)12GC-3‘ and 5‘-(AT)7-3‘, the existence of DA could not lead to the change of dsDNA signal and indicated that there is no interaction between DA and these two dsDNAs. 相似文献
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用高效毛细管电泳前沿分析法研究了酸性药物那格列奈与人血浆白蛋白的结合常数、结合位点和结合率。使用未涂层的毛细管柱 (4 0cm× 5 0 μmi.d .;有效柱长 32cm) ,磷酸盐缓冲溶液 (pH 7.4 ,离子强度0 .17)为背景溶液 ,在紫外检测波长 2 14nm、运行电压 18kV和重力进样 10 0s的条件下 ,利用那格列奈谱峰的平台高度和游离药物浓度的良好线性关系 (r>0 .999,n =6 ) ,测定了那格列奈的游离药物浓度。固定药物浓度 (2 0 0 μmol L ,2 5 0 μmol L) ,考察不同的蛋白质浓度对结合的影响 ;固定蛋白质浓度 (10 0 μmol L) ,考察不同的药物浓度对结合的影响。实验数据采用非线性拟和程序进行处理 ,得到了那格列奈的蛋白质结合参数。高效毛细管电泳前沿分析法测定的数据重现性良好 (RSD <2 .5 % ,n =3) ,在药代动力学和药效学研究方面具有简便、准确的优点。 相似文献
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The interaction of RT3 (R=Ce, Y; T=Ni, Co) intermetallic compounds (IMC)with alkaline solutions of MBH4 (M=Na, K, Rb, and Cs) was studied in the temperature range of 298–318 K. For all intermetallic compounds, the reaction of
catalytic hydrolysis of NaBH4 is zero order with respect to MBH4 and first order with respect to RT3. The reaction rate decreases and the activation energy of the catalytic hydrolysis of MBH4 increases in the following order. NaBH4, KBH4, RbBH4, and CsBH4. The hydride phases RT3Hx (x2.3—3.9) were synthesized by the interaction of RT3 IMC with alkaline solutions of MBH4. They are similar in composition to the products formed in the reaction of RT3 with gaseous hydrogen at high pressure. The rate of hydrogenation of RT3 in alkaline solutions of MBH4 decreases on going from sodium to cesium.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 921–923, May, 1997. 相似文献
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《Physics and Chemistry of Liquids》2012,50(4):459-473
Abstract The ultrasonic velocity, u, viscosity, η, and density, ρ of dimethylsulphoxide (DMSO), 1-butanol, 1-hexanol, 1-octanol, and of their binary mixtures, where DMSO is common component, have been measured at 303.15 K. From the experimental data, excess isentropic compressibility, K E s, excess intermolecular free length, LE f, excess velocity, u E, excess acoustic impedance, Z E, excess viscosity, ηE, excess free energy of activation of viscous flow, G?E, and excess rheochore, [R E] have been calculated. The behaviours of excess functions with composition of the mixtures suggest that the structure-breaking effect dominates over the interaction effect between the component molecules. Furthermore, the experimental values of u and η were fitted by empirical equations stating their dependence on composition of the mixtures. The experimental values of u have been compared with those calculated by using Nomoto and Van Dael relations. 相似文献
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Three systems of gold(III) complexes in an aqueous solution (I = 0.05 M, 25°C) with slow equilibration were studied by capillary electrophoresis. It was shown on an example of mixed chloride–hydroxide complexes Au(OH) i Cl 4-i - that, despite close sizes and identical charges of the forms, the mixed forms can be separated if they are kinetically inert. For the equilibria AuCl 4 ? + am = AuamCl 2 + + 2Cl– and AuamCl 2 + + am = + Auam23+ + 2Cl–, where am is ethylenediamine (en) and 1,3-diaminopropane (tn), the logarithmic constants were logK2 = 10.4 for en, and logK1 = 16.1 and logK2 = 12.0 for tn, which satisfactorily agrees with the spectrophotometric data. There was a considerable effect of side processes, insignificant under normal conditions. 相似文献
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P. M. Panasyuk S. F. Melnikova I. V. Tselinskii 《Chemistry of Heterocyclic Compounds》2005,41(7):909-913
The effect of substituents in position 6 on the positions of the signals of the carbon atoms in the 13C NMR spectra of substituted 1,2,3,4-tetrahydro-5,10-phenazine N,N′-dioxides has been analyzed, increments of substituents
have been found, and a scheme has been proposed for the calculation of the chemical shifts of carbon atoms in the 13C NMR spectra of 6(7)-R-quinoxaline N,N′-dioxides.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, 1076–1080, July, 2005. 相似文献
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《Physics and Chemistry of Liquids》2012,50(4):449-455
Excess molar enthalpies, $ H_m^E $ of N , N -dimethylacetamide + methanol, + ethanol, + propan-1-ol, + butan-1-ol, + pentan-1-ol, and + hexane-1-ol have been determined at 298.15 K and atmospheric pressure using a Parr 1455 solution calorimeter. While the excess molar enthalpies are negative for methanol and ethanol mixtures, those for propan-1-ol, butan-1-o1, pentane-1-ol, and hexan-1-ol mixtures are positive over the entire range of composition of N , N -dimethylacetamide. The $ H_m^E $ at around x , 0.5 follow the order: methanol<ethanol<propan-1-ol<butan-1-ol<pentan-1-ol<hexan-1-ol. The results are explained in terms of the self-association exhibited by the alkan-1-ols and the formation of aggregates between unlike molecules through OHO hydrogen bonding. The experimental results for mixtures are well represented by the Redlich - Kister equation. 相似文献
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Fullerenes C60 and C70 have high electron affinity ( 2.6 - 2.8 ev ) and readily form anions on electronchemical reduction1, which were famous as electron acceptor in photo-excitation because of symmetrical shape, large size, and properties of its p - electron system2. After observation of molecular ferromagnetism3 in the tetrakis (dimethylamino ) ethylene salt of C60 as well as the occurrence of ultra-fast photoinduced electron transfer within the dimethyl aniline - C60 complex4, prompted us… 相似文献
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The electronic structures of the HXY/XYH compounds (X[Double Bond]C,Si;Y[Double Bond]O,S) on the (2)A(') electronic ground state were investigated by applying the natural bond orbital (NBO) method to the computed B3LYP6-311G(**) wave functions. Different localized structures are proposed for the HXY and XYH isomers and the central XY unit is described as intermediate between a double and a triple bond in HCO, HCS, HSiO, and HSiS, similar to a double bond in COH, CSH, and SiSH, and clearly a single bond in SiOH. Through the comparison between the NBO results for the diatomic and hydrogenated compounds, the energy preferences on each pair of isomers and the computed geometrical parameters are explained. According to the structures proposed, the HXY compounds are sigma radicals with the spin density distributed along the molecular framework, while the XYH compounds are pi radicals with most of the unpaired spin located on an almost pure p orbital of the X atom. Finally, the amounts of spin density on natural atomic orbitals provided by the NBO method are used to explain the computed values of the isotropic and anisotropic hyperfine coupling constants. 相似文献
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Lu W Mi BX Chan MC Hui Z Zhu N Lee ST Che CM 《Chemical communications (Cambridge, England)》2002,(3):206-207
Tridentate cyclometalated platinum(II) complexes bearing sigma-alkynyl ligands exhibit tunable photoluminescence and enhanced stability during vacuum deposition; OLEDs based on these materials display orange to red electrophosphorescence with low turn-on voltages (approximately 4 V), maximum luminance approaching 10,000 cd m-2 and efficiency up to 4.2 cd A-1. 相似文献
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He Ping ZENG 《中国化学快报》2002,13(12)
Photoinduced electron transfer processes between fullerenes (C60 / C70) and N, N, N′, N′- tetra - ( p-methylphenyl ) - 4, 4′- diamino - 1, 1′- diphenyl ether ( TPDAE ) have been studied by nanosecond laser flash photolysis. Quantum yields and rate constants of electron transfer from TPDAE to excited triplet state of fullerenes (C60 / C70 ) in benzonitrile have been evaluated by observing the transient absorption bands in the near-IR region where the excited triplet state, radical anion of fullerenes ( C60 / C70 ) and radical cations of TPDAE appear. 相似文献
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Lowest-energy structures of (C60)nX (X=Li+,Na+,K+,Cl-) and (C60)nYCl (Y=Li,Na,K) clusters for n</=13
Hernández-Rojas J Bretón J Gomez Llorente JM Wales DJ 《The Journal of chemical physics》2004,121(24):12315-12322
Basin-hopping global optimization is used to find likely candidates for the lowest minima on the potential energy surface of (C(60))(n)X (X=Li(+),Na(+),K(+),Cl(-)) and (C(60))(n)YCl (Y=Li,Na,K) clusters with n=13. The energy is evaluated using the Girifalco form for the C(60) intermolecular potential along with a polarization potential, which depends on the first few nonvanishing C(60) multipole polarizabilities. We find that the ions occupy interstitial sites of a (C(60))(n) cluster, the coordination shell being triangular for Li(+), tetrahedral for Na(+) and K(+), and octahedral for Cl(-). When the required coordination site does not exist in the corresponding (C(60))(n) global minimum, the lowest minimum of the doped system may be based on an alternative geometry. This situation is particularly common in the Cl(-) complexes, where the (C(60))(n) global minima with icosahedral packing change into decahedral or closed-packed forms for the ions. In all the ions we find a significant binding energy for the doped cluster. In the alkali chloride complexes the preferred coordination for the diatomic moiety is octahedral and is basically determined by the Cl(-) ion. However, the smaller polarization energies in this case mean that a change in structure from the (C(60))(n) global minimum does not necessarily occur if there is no octahedral site. 相似文献