Effect Of Water On Brittle Fracture Of Sio2 By Molecular Dynamics Study

The influence of water on the brittle behavior of beta-cristobalite is studied by means of molecular dynamics (MD) simulation With the TTAM potential. Crack extension of mode 1 type is observed as the crack opening is filled LIP With water. The critical stress intensity factor K-lc(MD) is used to characterize the crack extension of MD simulation. The surface energy of SiO2 covered with layers of water is calculated at temperature of 300 K. Based oil the Griffith fracture criterion, the critical stress intensity factor K-lc(Griffith) is calculated, and it is in good agreement with that of MD simulation. (C) 2008 Elsevier B.V. All rights reserved.

Phage M13Ko7 Detection With Biosensor Based On Imaging Ellipsometry And Afm Microscopic Confirmation

A rapid detection and identification of pathogens is important for minimizing transfer and spread of disease. A label-free and multiplex biosensor based on imaging ellipsometry (BIE) had been developed for the detection of phage M13KO7. The surface of silicon wafer is modified with aldehyde, and proteins can be patterned homogeneously and simultaneously on the surface of silicon wafer in an array format by a microfluidic system. Avidin is immobilized on the surface for biotin-anti-M13 immobilization by means of interaction between avidin and biotin, which will serve as ligand against phage M13KO7. Phages M13KO7 are specifically captured by the ligand when phage M13KO7 solution passes over the surface, resulting in a significant increase of mass surface concentration of the anti-M13 binding phage M13KO7 layer, which could be detected by imaging ellipsometry with a sensitivity of 10(9) pfu/ml. Moreover, atomic force microscopy is also used to confirm the fact that phage M13KO7 has been directly captured by ligands on the surface. It indicates that BIE is competent for direct detection of phage M13KO7 and has potential in the field of virus detection. (C) 2008 Elsevier B.V. All rights reserved.