ABSTRACT
The micropipette aspiration technique was improved by selecting the uniform cells in round shape (UCR) from a number of adhered cells on the testing surface so as to measure the adhesion forces during the initial adhesion stage. Silk fibroin film and silk fibroin/fucoidan film were used as testing substrates. The testing results revealed that the modified micropipette method was more rapid for testing. The tendency of cell adhesion force on different materials surface under different conditions remained unchanged. The testing results showed good reproducibility. It was easy to distinguish small differences in the adhesiveness of endothelial cell on the silk fibroin based materials, thus exhibiting the high sensitivity of the improved method.
Subject(s)
Humans , Cell Adhesion , Physiology , Cells, Cultured , Endothelial Cells , Cell Biology , Fibroins , Umbilical Veins , Cell BiologyABSTRACT
Objective To establish a method for determination of trace lead in alginate sodium.Method The lead in the samples was determined by fluorescence spectroscopy after been digested by hydrothermal decomposition.Results The detection limit of lead was 2.71?10-2?g?mL-1.The relative standard deviation of the three samples were 4.06%,1.57% and 2.12% respectively,the average recovery was 88.32%～100.8%.Conclusion The method had the advantages of simple operation,higher precision,higher sensitivity and repeatability and was suitable for the determination of trace lead in the alginate sodium
ABSTRACT
Objective Rheological properties and gelation properties of agar were investigated. Methods The gelling point,melting point and the gel strength of agar were detected with MCR101 rheometer and TA texture testing instrument. Results and Conclusion Rheological properties of agar were affected by its concentration ,temperature and the addition of salt (such as NaCl ,CaCl2) and sucrose. Apparent viscosity exhibited shear thinning behavior following the power law model. Apparent viscosity increased with the increase of concentration,and decreased with the rise of temperature. The decrease in viscosity followed an Arrhenius temperature dependence. Agar solutions exhibited typical "weak gel" properties by small strain oscillatory measurements. The results indicated that the agar solution was characterized as a gel properties ,and which could form a kind of heat reversible gel. The gelling point of agar was lower than its melting point. The gel strength of agar could be affected by its gel time,and the addition of salt (such as NaCl,CaCl2) and sucrose.