Recalcitrant bubbles

We demonstrate that thermocapillary forces may drive bubbles against liquid flow in ‘anomalous' mixtures. Unlike ‘ordinary' liquids, in which bubbles migrate towards higher temperatures, we have observed vapour bubbles migrating towards lower temperatures, therefore against the flow. This unusual behaviour may be explained by the temperature dependence of surface tension of these binary mixtures. Bubbles migrating towards their equilibrium position follow an exponential trend. They finally settle in a stationary position just ‘downstream' of the minimum in surface tension. The exponential trend for bubbles in ‘anomalous' mixtures and the linear trend in pure liquids can be explained by a simple model. For larger bubbles, oscillations were observed. These oscillations can be reasonably explained by including an inertial term in the equation of motion (neglected for smaller bubbles)

Electrified falling film flow over topography in the presence of a finite electrode

The effect of an electric field on a liquid film flowing down an inclined wall is examined. The liquid film is treated as a perfect conductor and the air above the film is treated as a perfect dielectric. The electric field is created by a single or periodically repeated electrode of arbitrary shape charged to establish a prescribed potential difference between itself and the liquid-film surface. The steady deformation of the free surface in the presence of the electric field is computed first on the assumption of a thin film and next within the Stokes-flow regime. Calculations are performed for flow over a plane wall and over a step of asymptotically small height. In the latter case, the focused electric field obtained by positioning a circular electrode directly above the step is found to eliminate the capillary ridge identified by previous authors without significantly disrupting the flow away from the step. This result is confirmed numerically for Stokes flow over a step of arbitrary height using the boundary-element method

Phosphopeptide Selective Coordination Complexes as Promising Src Homology 2 Domain Mimetics

Src Homology 2 (SH2) domains are the paradigm of phosphotyrosine (pY) protein recognition modules and mediate numerous cancer-promoting protein–protein complexes. Effective SH2 domain mimicry with pY-binding coordination complexes offers a promising route to new and selective disruptors of pY-mediated protein–protein interactions. We herein report the synthesis and in vitro characterization of a library of coordination complex SH2 domain proteomimetics. Compounds were designed to interact with phosphopeptides via a two-point interaction, principally with pY, and to make secondary interactions with pY+2/3, thereby achieving sequence-selective discrimination. Here, we report that lead mimetics demonstrated high target phosphopeptide affinity (<i>K</i>_a ∼ 10⁷ M^–1) and selectivity. In addition, biological screening in various tumor cells for anticancer effects showed a high degree of variability in cytotoxicity among receptors, which supported the proposed two-point binding mode. Several receptors potently disrupted cancer cell viability in breast cancer, prostate cancer, and acute myeloid leukemia cell lines