分子环境变化对振动退相时间影响的实验研究

物质分子振动退相时间测量是一种非标记无损分子检测方法, 用超连续谱时间分辨相干反斯托克斯拉曼散射方法可同时获得分子振动谱和退相时间. 实验以苯甲腈和甲醇为样品, 研究当分子环境变化时, 其主要振动谱的振动退相时间变化情况. 将苯甲腈与无水乙醇混合, 测量了苯甲腈分子1017, 2247和3085 cm^-1三个典型分子振动的退相时间随环境变化的规律, 并得到了变化后的振动退相时间. 测量了甲醇分子2851, 2960 cm^-1两个相邻分子振动的退相时间随环境的变化情况, 给出实验变化规律. 这种方法具有检测分子所处环境变化和分子相互作用的能力, 在生命科学、分子生物学和材料科学等研究领域中具有重要的应用前景.     

Computational discovery and experimental verification of tyrosine kinase inhibitor pazopanib for the reversal of memory and cognitive deficits in rat model neurodegeneration

Cognition and memory impairment are hallmarks of the pathological cascade of various neurodegenerative disorders. Herein, we developed a novel computational strategy with two-dimensional virtual screening for not only affinity but also specificity. We integrated the two-dimensional virtual screening with ligand screening for 3D shape, electrostatic similarity and local binding site similarity to find existing drugs that may reduce the signs of cognitive deficits. For the first time, we found that pazopanib, a tyrosine kinase inhibitor marketed for cancer treatment, inhibits acetylcholinesterase (AchE) activities at sub-micromolar concentration. We evaluated and compared the effects of intragastrically-administered pazopanib with donepezil, a marketed AchE inhibitor, in cognitive and behavioral assays including the novel object recognition test, Y maze and Morris water maze test. Surprisingly, we found that pazopanib can restore memory loss and cognitive dysfunction to a similar extent as donepezil in a dosage of 15 mg kg^–1, only one fifth of the equivalent clinical dosage for cancer treatment. Furthermore, we demonstrated that pazopanib dramatically enhances the hippocampal Ach levels and increases the expression of the synaptic marker SYP. These findings suggest that pazopanib may become a viable treatment option for memory and cognitive deficits with a good safety profile in humans.     

Structure theorem for dual quasi-hopf bicomodules and its application

We present a structure theorem for dual quasi-Hopf bicomodules, and also obtain the structure theorem C ≌ D ? H for dual quasi-Hopf module coalgebras, where H is a dual quasi-Hopf algebra, C a right H-module coalgebra, and D a left H-comodule coalgebra in the tensor category ^H M induced from C, and D ? H the smash coproduct introduced by Bulacu and Nauwelaerts.     

Sensitive Determination of Thiols Using SPE Coupled to LC with Fluorescence Detection

The purpose of the present work is to develop a simple, rapid, sensitive and accurate method for the derivatization and subsequently preconcentration of Hg(II) and the determination of its derivative, diphenylmercury, in natural water samples using gas chromatography-flame ionization detection. The method is based on the diphenylation using phenyl boronic acid, subsequent extraction of phenylmercury into a single drop of an organic solvent (toluene), followed by gas chromatography-flame ionization detection GC-FID analysis of the extract. The pH of the feed solution was kept in pH 5 with acetate buffer solution. Thus, the optimized conditions are: organic solvent, toluene; derivatization time, 10 min; extraction time, 15 min; microdrop volume, 1.6 μL; stirring rate, 600 rpm; sample volume, 5 mL. The limit of detection (LOD), calculated on the basis of five replicates was 0.02 μg mL^?1. The relative standard deviation of the method (RSD%, n = 5) was 3.0. Linear range was between 0.05 and 5 μg mL^?1 and preconcentration factor obtained for phenyl-mercury was 105.     

Separation and Determination of Monovalent and Divalent Cations by the Facile Propylsulfonic Acid Functionalized Silica Stationary Phase

A facile strong cation-exchange stationary phase based on propylsulfonic acid functionalized silica was prepared through the oxidation in situ of 3-mercaptopropyl silica and characterized by elemental analysis and X-ray photoelectron spectroscopy. The phase was used to separate monovalent and divalent inorganic cations with strong acid as mobile phase. Simultaneous separation of alkali metals and alkaline earth metals was examined and the cations sodium, magnesium and calcium in tap water were determined.     

Preparation of carbon coated Fe3O4 nanoparticles and their application for solid-phase extraction of polycyclic aromatic hydrocarbons from environmental water samples

The carbon coated Fe₃O₄ nanoparticles (Fe₃O₄/C) were synthesized by a simple hydrothermal reaction and applied as solid-phase extraction (SPE) sorbents to extract trace polycyclic aromatic hydrocarbons (PAHs) from environmental water samples. The Fe₃O₄/C sorbents possess high adsorption capacity and extraction efficiency due to strong adsorption ability of carbon materials and large surface area of nanoparticles, and only 50 mg of sorbents are required to extract PAHs from 1000 mL water samples. The adsorption attains equilibrium rapidly and analytes are eluted with acetonitrile readily. Salinity and solution pH have no obvious effect on the recoveries of PAHs, which avoids fussy adjustment to water sample before extraction. Under optimized conditions, the detection limits of PAHs are in the range of 0.2–0.6 ng L⁻¹. The accuracy of the method was evaluated by the recoveries of spiked samples. Good recoveries (76–110%) with low relative standard deviations from 0.8% to 9.7% are achieved. This new SPE method provides several advantages, such as high extraction efficiency, high breakthrough volumes, convenient extraction procedure, and short analysis times. To our knowledge, this is the first time that Fe₃O₄/C nanoparticles are used for the pretreatment of environmental water samples.     

One dimensional molecular dipole chain arrays on graphite via nanoscale phase separation

Molecular dipole chain arrays of chloroaluminium phthalocyanine (ClAlPc) on the graphite surface have been investigated by scanning tunneling microscopy. The inter-chain spacing can be tuned by the co-adsorption of di-indenoperylene (DIP) via nanoscale phase separation.     

Tunable activity in electrochemical reduction of oxygen by gold–polyaniline porous nanocomposites

Oxygen electrochemical reduction on gold–polyaniline (Au–PANI) porous nanocomposite-modified glassy carbon electrode in basic media was described. The as-prepared Au–PANI porous nanocomposite showed superior tunable activity for electrochemical reduction of oxygen. The specific surface area of Au–PANI porous nanocomposites was evaluated to be about 11.3 m² g⁻¹ through a convenient voltammetric approach. Rotating ring-disk electrode experiments further demonstrated the number of electrons exchanged in oxygen reduction increased from 2e to 4e with increasing the trigger potential from 300, to 500, 700 mV. The tunable activity in electrochemical reduction of oxygen was achieved as a result of positive potential-induced formation and reduction of Au surface oxide. However, the tunable oxygen reduction reaction is fit for applying potential in a linear positive-going potential sweep. Irreversible ORR tunability was found after a more active surface formed at 700 mV. To optimize the applied potential window on these Au-based porous materials has potential applications such as in electrochemical sensing, fuel cells, or getting rid of the interference from the coexisted substances.     

Synthesis of nano/microstructures at fluid interfaces

The generation of novel multifunctional materials with hierarchical ordering is a major focus of current materials science and engineering. For such endeavors, fluid interfaces, such as air-liquid and liquid-liquid interfaces, offer ideal platforms where nanoparticles or colloidal particles can accumulate and self-assemble. Different assembly processes and reactions have been performed at fluid interfaces to generate hierarchical structures, including two-dimensional crystalline films, colloidosomes, raspberry-like core-shell structures, and Janus particles, which lead to broad applications in drug delivery and controlled release, nanoelectronics, sensors, food supplements, and cosmetics.