A new bonded RP-18 sintered silica gel plate for use in reversed-phase planar electrochromatography has been prepared in our laboratory by fusing a mixture of silica gel and glass powder then reaction with octadecyltrichlorosilane. The plates have good chromatographic characteristics and other useful properties, for example mechanical stability, and can be regenerated by soaking the chromatogram in acetone. Use of the new plate in a development chamber designed for planar electrochromatography, with a 2-kV intermittent voltage supply and a mobile phase prepared from aqueous acetonitrile containing 25 mM
sodium acetate buffer, pH 5.0, resulted in good separation of five dyes.
Authors:Jie Wang, Dongyuan Wang, Gaohong She, Zuo Wang, Jing Wang, Hongxia Zhang, Ledao Li and Ge Wang
In this paper a semi-automatic sample applicator made in an ordinary laboratory without help from others is described in detail. All the components of the applicator are available commercially at low cost and the process of assembly of the applicator is very simple and practical, especially the spraying head and the applicator mechanism. Factors that could affect the function of the applicator, for example the type and position of the spraying head, the gas pressure, and the application speed were tested. The type and position of the spraying head have a discernible effect whereas gas pressure does not. The relative standard deviation of band length and band width are <1% and <2.5%, respectively. The errors mainly arise from the clearance of the screw used for transmission of the shaft. The mechanism of the processes affecting band uniformity were researched and are described in detail. The application speed is an important factor, the faster the application speed, the better.
Authors:Yuping Wang, Dongyuan Wang, Jie Wang, Zhili Xiong, Hongxia Zhang, Gaohong She, Jian Li and Shengtao Xiao
A new AMD instrument made in our laboratory is described in this paper. The main advantages of the instrument are very low cost both of construction and in use. Compared with ascending development in conventional instruments, a laboratory-made horizontal sandwich chamber is used for development, and, with the help of a series of special accessories, no obvious mobile phase remains in the distributor after each step; this saves a large amount of solvent. All the components of the instrument are easy to obtain, so the average worker in a chemical laboratory could construct all the instrument except the control unit. An application of the instrument is described; the results obtained were satisfactory.
Authors:Hongxia Wang, Yan Sun, Fan Lan and Yan Liu
Background and aims
The working memory (WM) ability of internet addicts and the topology underlying the WM processing in internet addiction (IA) are poorly understood. In this study, we employed a graph theoretical framework to characterize the topological properties of the IA brain network in the source cortical space during WM task.
A sample of 24 subjects with IA and 23 matched healthy controls (HCs) performed visual 2-back task. Exact Low Resolution Electromagnetic Tomography was adopted to project the pre-processed EEG signals into source space. Subsequently, Lagged phase synchronization was calculated between all pairs of Brodmann areas, the graph theoretical approaches were then employed to estimate the brain topological properties of all participants during the WM task.
We found better WM behavioral performance in IA subjects compared with the HCs. Moreover, compared to the HC group, more integrated and hierarchical brain network was revealed in the IA subjects in alpha band. And altered regional centrality was mainly resided in frontal and limbic lobes. In addition, significant relationships between the IA severity and the significant altered graph indices were found.
In conclusion, these findings provide evidence to support the notion that altered topological configuration may underline changed WM function observed in IA.