Molecular simulation study on the self-assembly behaviors of zwitterionic heterogemini surfactant in aqueous solution

The self-assembly behaviors of a series of zwitterionic heterogemini surfactants C_mH_2m+1-PO^4–(CH₂)₂-N⁺(CH₃)₂-C_nH_2n+1, abbreviated as C_m-P-N-C_n (m, n?=?9, 9; 9, 12; 9, 15; 9, 18; 12, 12; 12, 15; 12, 18; 15, 15; 15, 18; 18, 18), have been investigated in aqueous solution by the dissipative particle dynamics (DPD) method. Morphologies such as sphere (S), rod (R), planar grid (PG), lamella (L), honeycomb (H), one-, two-, and three-dimensional tunnels (1DT, 2DT, and 3DT) have been observed showing more diversities than those of the corresponding symmetric gemini surfactants C_m-N-N-C_m (m?=?9, 12, 15, 18). With the increase of surfactant concentration in the aqueous solution, a distinct transition path ‘‘S—R—PG—3DT—L—2DT—1DT’’ is proved to be common for all the C_m-P-N-C_n systems. Besides, the hydrophobic chain length has a significant influence on the self-assembly behaviors in the case of m?≠?n. Radial distribution function is an effective method to quantitatively evaluate the interaction and relationship between each functional group in the surfactant molecule and water. Results can provide a new insight into the self-assembly behaviors of zwitterionic heterogemini surfactants and the corresponding applications.     

Microwave‐assisted extraction in combination with HPLC‐UV for quantitative analysis of six bioactive oxoisoaporphine alkaloids in Menispermum dauricum DC

A novel and reliable method based on microwave‐assisted extraction (MAE) followed by HPLC‐UV was developed and validated for the simultaneous quantification of six pharmacologically important oxoisoaporphine alkaloids in the total plants of Menispermum dauricum DC. The optimal MAE extraction condition was performed at 60°C for 11 min with ethanol–water (70:30, v/v) as the extracting solvent, and the solvent to solid ratio was 20:1. Chromatographic separation was achieved on a reversed‐phase YMC C₁₈ column (250 × 4.6 mm, i.d., 5 µm) with a gradient mobile phase consisting of A (1% aqueous formic acid) and B (acetonitrile containing 1% formic acid) at a flow rate of 1.5 mL/min. The detection wavelength was set at 422 nm. Excellent linearity over the investigated concentration ranges was observed with values of r >0.999 for all analytes. The method developed was validated with acceptable sensitivity, intra‐ and inter‐day precision and extraction recoveries. It was successfully applied to the determination of six alkaloids in Menispermum dauricum DC from different sources and different parts of Menispermum dauricum DC. The results obtained indicated that the method is suitable for the quality control of Menispermum dauricum DC. Copyright © 2015 John Wiley & Sons, Ltd.     

平面钢筋混凝土框架结构优化

采用Matlab和ANSYS混合编程的方法编写了平面钢筋混凝土框架结构的优化设计程序,充分发挥了各自的优势,节约了结构优化程序的开发成本.程序中调用ANSYS完成结构有限元分析,而后采用Matlab中遗传算法(GA函数)完成优化分析,二者之间通过调用磁盘文件的方法进行数据传递.最后通过算例分析证明了程序的可行性,同时根据结果对比进一步验证了遗传算法在结构优化方面的优势.程序用户界面友好,操作方便,对结构优化实用化的发展起到一定促进作用.     

Theoretical and experimental studies on a compact stretcher with large spectral bandwidth and high transmission efficiency

To ensure safe and effective amplification for the chirped pulse amplification laser facility, many factors such as pulse spectral width, pulse duration, grating parameters and incidence angle parameter are considered carefully in the design of the pulse stretcher. A compact four pass Offner stretcher design is given out. Experiment results show that the stretcher has broad spectral width, large stretching ratio and high transmission efficiency. By comparison, the calculated result of the dispersion effect on the pulse duration is completely consistent with the experiment result.     

A facile one-step route to synthesize titania hollow microspheres with incontinuous multicavities

The titania hollow microspheres with incontinuous multicavities were successfully fabricated via an oil/ water(O/W) emulsion process accompanied by sol–gel reaction in the presence of polyvinylpyrrolidone(PVP). In the one-step route, the addition of PVP to the tetrabutyl titanate(TBT) 1-octanol solution as the oil phase of the O/W emulsion clearly expands the size of the cavities inside the microspheres. The and atoleine alters the polarity of the oil phase to affect the interior structure significantly. The Span 80 is used as a stabilizer to preserve spherical shape. A preliminary mechanism based on phaseseparation for the structural evolution of titania hollow microspheres with multicavities is suggested. Zirconia and alumina hollow microspheres with incontinuous multicavities can also be prepared by this one-step route successfully.     

Standing Waves for Discrete Nonlinear Schrödinger Equations with Nonperiodic Bounded Potentials

Acta Mathematicae Applicatae Sinica, English Series - In this paper, we investigate standing waves in discrete nonlinear Schrödinger equations with nonperiodic bounded potentials. By using the...     

有限CN-p-群

每个子群都C-正规的有限群称为CN-群.本文首先给出二元生成的CN-p-群的完全分类.在此基础上得到CN-p-群的结构:当p为奇素数时,有限群G为CNp-群当且仅当G的每个元都平凡地作用在Φ(G)上;有限群G为CN-2-群当且仅当对任意给定的a∈G,都有对任意g∈Φ(G),g~a=g或者对任意g∈Φ(G),g~a=g~(-1).最后给出两个CN-p-群的直积是CN-p-群的判定条件.     

Low‐Magnetization Magnetic Microcapsules: A Synergistic Theranostic Platform for Remote Cancer Cells Therapy and Imaging

Multifunctional magnetic microcapsules (MMCs) for the combined cancer cells hyperthermia and chemotherapy in addition to MR imaging are successfully developed. A classical layer‐by‐layer technique of oppositely charged polyelectrolytes (poly(allylamine hydrochloride) (PAH) and poly(4‐styrene sulfonate sodium) (PSS)) is used as it affords great controllability over the preparation together with enhanced loading of the chemotherapeutic drug (doxorubicin, DOX) in the microcapsules. Superparamagnetic iron oxide (SPIOs) nanoparticles are layered in the system to afford MMC1 (one SPIOs layer) and MMC2 (two SPIOs layers). Most interestingly, MMC1 and MMC2 show efficient hyperthermia cell death and controlled DOX release although their magnetic saturation value falls below 2.5 emu g^?1, which is lower than the 7–22 emu g^?1 reported to be the minimum value needed for biomedical applications. Moreover, MMCs are pH responsive where a pH 5.5 (often reported for cancer cells) combined with hyperthermia increases DOX release predictably. Both systems prove viable when used as T2 contrast agents for MR imaging in HeLa cells with high biocompatibility. Thus, MMCs hold a great promise to be used commercially as a theranostic platform as they are controllably prepared, reproducibly enhanced, and serve as drug delivery, hyperthermia, and MRI contrast agents at the same time.