尺寸排阻色谱-电感耦合等离子体质谱联用技术研究牛血清白蛋白与顺铂的反应动力学

顺铂是广泛应用的抗肿瘤药物,生理盐水稀释后通过静脉注射到体内.研究顺铂和血浆蛋白间的相互作用对理解其药效十分重要.本实验利用尺寸排阻色谱-电感耦合等离子体质谱(SEC/ICP-MS)联用技术研究了顺铂和牛血清白蛋白(BSA)的反应速率常数.顺铂与BSA于37℃孵育3,6,9,17和24 h后,用SEC/ICPMS分析顺铂及顺铂-BSA复合物铂,从而计算出顺铂和BSA的反应速率常数为0.077 h-1.方法对于铂的检出限为0.19 ng/g.     

Evaluation of Metal Ions and Surfactants Effect on Cell Growth and Exopolysaccharide Production in Two-Stage Submerged Culture of Cordyceps militaris

During the two-stage submerged fermentation of medicinal mushroom Cordyceps militaris, it was found that K⁺, Ca²⁺, Mg²⁺, and Mn²⁺ were favorable to the mycelial growth. The EPS production reached the highest levels in the media containing Mg²⁺ and Mn²⁺. However, Ca²⁺ and K⁺ almost failed to increase significantly exopolysaccharides (EPS) production. Sodium dodecyl sulfate (SDS) significantly enhanced EPS production compared with that of without adding SDS when SDS was added on static culture stage of two-stage cultivation process. The presence of Tween 80 in the medium not only simulated mycelial growth but also increased EPS production. By response surface methods (RSM), EPS production reached its peak value of 3.28?g/L under optimal combination of 27.6?mM Mg²⁺, 11.1?mM Mn²⁺, and 0.05?mM SDS, which was 3.76-fold compared with that of without metal ion and surfactant. The results obtained were useful in better understanding the regulation for efficient production of EPS of C. militaris in the two-stage submerged culture.     

Facile synthesis of 1-bromo-7-alkoxyl perylene diimide dyes: toward unsymmetrical functionalizations at the 1,7-positions

In this Letter, we report a facile approach to synthesize unsymmetrical 1-bromo-7-alkoxyl perylene diimides by the nucleophilic substitution of one of the two 1,7-dibromo units with an alkyl alcohol using K₂CO₃ as the base. A further replacement of another bromo, for example, by using 4-hydroxylpyridine resulted in unsymmetrical functionalizations at the 1,7-positions. The optical properties of the unsymmetrical PDI derivative were reported and compared with those of the symmetrical derivative.     

Synthesis, characterization, and antibacterial activity of a cobalt(II) Schiff base complex derived from pyridoxal and sulfanilic acid

Reaction of pyridoxal hydrochloride and sulfanilic acid with CoCl₂ in aqueous methanol solution afforded a Co(II) Schiff base complex, which was characterized by physico-chemical and spectroscopic methods. The structure of the complex was determined by single crystal X-ray diffraction. In the complex, the Co(II) is sandwiched at the edge of two parallel Schiff base ligands, being coordinated by two phenolic O and two imine N atoms of two Schiff base ligands plus two O atoms of water ligands, forming a distorted octahedral coordination environment. Thermal stability measurements showed that the skeleton of the complex is stable up to 500?K. The antibacterial activity of the complex was screened using the paper disc diffusion method.     

偶联剂对Mn-Zn铁氧体颗粒分散性及磁性能的影响

本研究采用沸腾回流共转化法制备锰锌铁氧体纳米颗粒的基础上,分别采用TC-114(钛酸酯)、KH-151(硅烷)、TC-114与KH-15复配对铁氧体颗粒进行包覆。结果表明:包覆后的锰锌铁氧体纳米颗粒均是尖晶石结构,偶联剂包覆使纳米锰锌铁氧体颗粒尺寸变小,其中TC-114与KH-151复配后包覆得到的锰锌铁氧体纳米颗粒粒径最小(17.7 nm),比未包覆的颗粒减少10.9 nm。经TC-114、KH-151包覆后的锰锌铁氧体颗粒FT-IR光谱中分别出现了Ti-O-Fe,Si-O-S两个新的吸收峰。Zeta电位测试结果表明其有最低电位-46.1 mV,在所测pH范围最稳定(绝对值均大于30 mV),分散效果最佳。烧结后包覆颗粒的饱和磁化强度大幅提高,其中经TC-114与KH-151复配包覆的颗粒比未包覆提高了29.5%,矫顽力降低了32.3%。     

Studies on the interaction of gliclazide with bovine serum albumin by fluorescence and synchronous fluorescence spectroscopy

The interaction between gliclazide and bovine serum albumin was investigated by fluorescence and synchronous fluorescence spectroscopy. From the experimental results, it was found that the quenching mechanism was static. The results of the synchronous fluorescence obtained indicated that the binding of gliclazide with bovine serum albumin could affect conformation in bovine serum albumin. In addition, the binding constants (K_a), binding sites (n), thermodynamic parameters, binding forces, Hill’s coefficient, and binding rate of gliclazide to protein calculated from two methods using the same equation were consistent at three different temperatures (298, 310, 318 K). This indicated that as a useful supplement to the conventional method, synchronous fluorescence spectroscopy could be used to study the mechanism of drugs and proteins. The conclusion was verified by UV/vis method.     

Numerical and experimental analysis of the critically refracted longitudinal beam

The critically refracted longitudinal (L_CR) wave can be used in numerous non-destructive testing (NDT) applications, such as characterization of surface geometric aspects, subsurface defect detection and mostly for residual stress measurement. However, very few works characterize the associated ultrasonic beam. This paper deals with characterization of the L_CR beam profile both numerically and experimentally in order to optimize the incident angle choice in order to have sufficient energy in the experimental signal. The simulations are performed in time and frequency domains concerning solid elastic, homogenous and isotropic materials taking into account the liquid–solid interaction of the excitation by a water-coupled transducer. In the obtained results all components of the refracted acoustical field are demonstrated, as well as energy distributions of L_CR wave obtained with different incident angles.     

Numerical study of the advantages of ultraviolet light-emitting diodes with a single step quantum well as the electron blocking layer

The advantages of ultraviolet light-emitting diodes with a single step quantum well used as electron blocking layer (EBL) are studied numerically. The energy band diagrams, hole concentrations, electrostatic field near the EBL, current–voltage curve and internal quantum efficiency (IQE) are investigated by using the Crosslight simulation programs. The simulation results show that the structure with a single step quantum well has better performance over the conventional one, which can be attributed to the mitigated band bending near the EBL due to the change of electrostatic field by using a step well. Therefore, the efficiency of hole injection is improved, with which both the IQE and the total lighting power are increased.     

Efficient scheme for three-photon Greenberger–Horne–Zeilinger state generation

We propose an efficient scheme for the generation of three-photon Greenberger–Horne–Zeilinger (GHZ) state with linear optics, nonlinear optics and postselection. Several devices are designed and a two-mode quantum nondemolition detection is introduced to obtain the desired state. It is worth noting that the states which have entanglement in both polarization and spatial degrees of freedom are created in one of the designed setups. The method described in the present scheme can create a large number of three-photon GHZ states in principle. We also discuss an approach to generate the desired GHZ state in the presence of channel noise.