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).
The ice island, which is about half the height of the Empire State Building, is the biggest piece of ice to break away from the Arctic icecap since 1962 and amounts to a quarter of the Petermann 70-kilometer floating ice shelf, according to research leader Andreas Muenchow.
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.