INFLUENCE OF SHEAR ON POLYMER ADSORPTION-KINETICS

Kinetics of poly(methylmethacrylate) adsorption onto a single surface from dilute carbon tetrachloride solution is reported. From stagnant solution the well-known steady-state plateau level of mass adsorbed is approached at long times. However, the mass adsorbed resumes its rise when moderate shear flow is initiated. For adsorption onto an initially bare surface, at a shear rate of 3 sec ???1, there is no sign of plateau on the logarithmic time scale

Sonic Hedgehog regulates Hes1 through a novel mechanism that is independent of canonical Notch pathway signalling

Aberrant regulation of signalling mechanisms that normally orchestrate embryonic development, such as the Hedgehog, Wnt and Notch pathways, is a common feature of tumorigenesis. In order to better understand the neoplastic events mediated by Hedgehog signalling, we identified over 200 genes regulated by Sonic Hedgehog in multipotent mesodermal cells. Widespread crosstalk with other developmental signalling pathways is evident, suggesting a complex network of interactions that challenges the often over-simplistic representation of these pathways as simple linear entities. Hes1, a principal effector of the Notch pathway, was found to be a target of Sonic Hedgehog in both C3H/10T1/2 mesodermal and MNS70 neural cells. Desert Hedgehog also elicited a strong Hes1 response. While Smoothened function was found necessary for upregulation of Hes1 in response to Sonic Hedgehog, the mechanism does not require [gamma]-secretase-mediated cleavage of Notch receptors, and appears to involve transcription factors other than RBP-J[kappa]. Thus, we have defined a novel mechanism for Hes1 regulation in stem-like cells that is independent of canonical Notch signalling