Mechanism of Action. Levocetirizine, the active enantiomer of cetirizine, is an anti histamine; its principal effects are mediated via selective inhibition of H1 receptors. The antihistaminic activity of levocetirizine has been documented in a variety of animal and human models. In vitro binding studies revealed that levocetirizine has an affinity for the human H1-receptor 2-fold higher than that of cetirizine (Ki = 3 nmol/L vs. 6 nmol/L, respectively).
Glacier Calf That Broke Off Greenland's Jakobshavn Could Be Largest Ever. The Jakobshavn glacier-Greenland's fastest-moving glacier located near Ilulissat-is seen in a NASA image taken by the Operational Land Imager (OLI) on the Landsat 8 satellite August 16, 2015.
The upper 50 meters of a glacier is not under enough pressure to have plastic flow. The surface of the glacier behaves differently than the ice below. This uppermost zone of a glacier is brittle, and it si referred to as the zone of fracture. This brittle topmost ice piggybacks a ride on the flowing ice below. The zone of fracture experiences tension when the glacier moves over irregular terrain. This tension results in gaping cracks called crevasses.