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261.
262.
Xudong Jin Yuwei Guo Jun Wang Zhiqiu Wang Jingqun Gao Baoxin Wang Shujun Wang Yongnan Xu 《Journal of solution chemistry》2012,41(1):112-129
Sonodynamic therapy (SDT) is an innovative cancer treatment involving a tumor-localizing sonosensitizer. The synthesis, modification
and activity of novel sonosensitizers have attracted more and more researchers’ attention. In the present study, chlorophyll-magnesium
(Chl-Mg) and metronidazole (MTZ) were used as reactants and the chlorophyll-magnesium linked metronidazole complex (chlorophyll-magnesium-metronidazole,
Chl-Mg-MTZ) was synthesized and characterized. Bovine serum albumin (BSA) was selected as the target protein; the biomolecule
affinity and sonodynamic activity of Chl-Mg-MTZ were assessed by their UV–vis and fluorescence spectra. The results indicate
that the interaction of Chl-Mg-MTZ to BSA is comparable with that of chlorophyll-magnesium (Chl-Mg). However, during damage
of BSA, Chl-Mg-MTZ shows a higher sonodynamic activity than chlorophyll-magnesium (Chl-Mg). Moreover, synchronous fluorescence
spectroscopy indicates that Chl-Mg-MTZ has similar binding ability with the tyrosine (Tyr) and tryptophan (Trp) residues of
BSA molecules. However, the damage is mainly focused on the Trp residues. In addition, the production of reactive oxygen species
(ROS) in the sonodynamic process was detected through the oxidation-extraction of 1,5-diphenylcarbazide (DPCI). The results
promote the potential of Chl-Mg-MTZ as a new sonosensitive drug for use in SDT, encouraging further study on tumor treatment. 相似文献
263.
Mingshan Xue Juan Xie Wen Li Fajun Wang Junfei Ou Chenggang Yang Changquan Li Zhenchen Zhong Zhonghao Jiang 《Journal of Physics and Chemistry of Solids》2012,73(6):781-787
Corrosion behavior of a material is complicated and can affect strongly its surface physical and chemical properties. In this study, the effect of corrosion on surface morphology and electron work function (EWF) of various Al alloys was comparatively investigated using a scanning electron microscopy and a scanning Kelvin probe. The experimental results showed that the change in EWF with corrosion time was not linear, but firstly increased and then decreased. The theoretical treatments demonstrated that such a change in EWF did not only depend on the surface roughness, but also correlate with oxide layers formed at the surfaces of Al alloys. The present results can also be used to reasonably explain the correlation between surface roughness and EWF reported previously. 相似文献
264.
Statistical properties of the electrophoretic collision of a long DNA molecule with a small obstacle
We present experimental results for the collision of a single λ-DNA molecule with isolated cylindrical nanoposts whose radii range from 350 nm to 1.37 μm. The experimental apparatus was fabricated in oxidized silicon using a plasma-thinning method. The probability density for the dimensionless holdup time is described by a gamma distribution, which accurately represents the behavior of the probability density for X collisions and U/J collisions for short-lived and long-lived collisions, respectively. The shape parameter of the gamma distribution reflects the nature of the short-lived collisions, whereas the scaling parameter captures the role of the finite size of the post on the U/J collisions. When rendered in an appropriate dimensionless form, the existing models for the role of electric field gradients extend to all post sizes, indicating that 350 nm is still well above the point-sized limit. Our experiments provide insights into a regime that is very challenging for numerical simulations but highly relevant for separation processes. 相似文献
265.
In this work a chip-based nano HPLC coupled MS (HPLC-chip/MS) method with a simple sample preparation procedure was developed for the flavonoid profiling of soybean. The analytical properties of the method including the linearity (R(2) , 0.992-0.995), reproducibility (RSD, 1.50-7.66%), intraday precision (RSD, 1.41-5.14%) and interday precision (RSD, 2.76-16.90%) were satisfactory. Compared with the conventional HPLC/MS method, a fast extraction and analysis procedure was applied and more flavonoids were detected in a single run. Additionally, 13 flavonoids in soybean seed were identified for the first time. The method was then applied to the profiling of six varieties of soybean sowed at the same place. A clear discrimination was observed among different cultivars, three isoflavones, accounting for nearly 80% of total flavonoid contents, were found increased in the spring soybeans compared with the summer cultivars. 相似文献
266.
Five meso-substituted cobalt(III) corroles were examined as to their catalytic activity for the electoreduction of O(2) when coated on an edge-plane pyrolytic graphite electrode in 1.0 M HClO(4). The investigated compounds are represented as (TpRPCor)Co(PPh(3)), where TpRPCor is the trianion of a para-substituted triphenylcorrole and R = OMe, Me, H, F, or Cl. Three electrochemical techniques, cyclic voltammetry, linear sweep voltammetry with a rotating disk electrode (RDE), and voltammetry at a rotating ring disk electrode (RRDE), were utilized to evaluate the catalytic activity of the corroles in the reduction of O(2). Cobalt corroles containing electron-withdrawing substituents were shown to be better catalysts than those having electron-donating groups on the three meso-phenyl rings of the triarylcorroles. 相似文献
267.
Effects of the structural order of canthaxanthin on the Raman scattering cross section in various solvents: A study by Raman spectroscopy and ab initio calculation
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In this work,we measure the Raman scattering cross sections(RSCSs) of the carbon-carbon(CC) stretching vibrational modes of canthaxanthin in benzene,acetone,n-heptane,cyclohexane,and m-xylene.It is found that the absolute RSCS of CC stretching mode of canthaxanthin reaches a value of 10 24 cm 2 ·molecule 1 ·sr 1 at 8×10 5 M,which is 6 orders of magnitude larger than general RSCS(10 30 cm 2 ·molecule 1 ·sr 1),and the RSCSs of canthaxanthin in various solvents are very different due to the hydrogen bond.A theoretical interpretation of the magnetic experimental results is given,which is introduced in a qualitative nonlinear model of coherent weakly damped electron-lattice vibration in the structural order of polyene chains.In addition,the optimal structure and the bond length alternation(BLA) parameter of canthaxanthin are calculated using quantum chemistry calculation(at the b3lyp/6-31g(d,p) level of theory).The theoretical calculations are in good agreement with the experimental results.Furthermore,the combination of Raman spectroscopy and the quantum chemistry calculation study would be a quite suitable method of studying the structures and the properties of the π-conjugated systems. 相似文献
268.
BEHAVIOR OF AIR-ENTRAINED CONCRETE AFTER FREEZE-THAW CYCLES 总被引:2,自引:0,他引:2
Huaishuai Shang Yupu Song Jinping Ou 《Acta Mechanica Solida Sinica》2009,22(3):261-266
The experimental study of air-entrained concrete specimens subjected to different cycles of freeze-thaw was completed. The dynamic modulus of elasticity, weight loss, the cubic compressive strength, compressive strength, tensile strength and cleavage strength of air-entrained concrete were measured after 0, 100, 200, 300, 400 cycles of freeze-thaw. The experimental results showed that the dynamic modulus of elasticity and strength decreased as the freeze-thaw was repeated. The influences of freeze-thaw cycles on the mechanical properties, the dynamic modulus of elasticity and weight loss were analyzed according to the experimental results. It can serve as a reference for the maintenance, design and the life prediction of dams, hydraulic structures, offshore structures, concrete roads and bridges in northern cold regions. 相似文献
269.
表面等离子共振技术测定生长抑素含量 总被引:1,自引:1,他引:0
应用表面等离子共振(SPR)技术建立了一种快速检测生长抑素(SST)含量的方法, 在pH=5.0, SST浓度为75 μg/mL的最佳偶联条件下, SST在CM5芯片上的偶联值为1231.7 Response unit(RU). 选择117.7 nmol/L作为固定的大分子量抗体浓度, 用抗原-抗体-抗原结合法检测SST纯品, 在20~2000 pg范围内, SST纯品含量和RU值之间可建立直线相关的标准曲线, R=-0.824, p<0.05, 变异系数CV=1.3%. 所建立的方法测定SST含量的范围为20~2000 pg, 重复性好且可随时检测, 有望用于SST的临床即时检测. 相似文献
270.