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.
NASA satellites observed the calving, or breaking off, of one of the largest icebergs ever recorded, named C-19.. C-19 separated from the western face of the Ross Ice Shelf in Antarctica in May 2002, splashed into the Ross Sea, and virtually eliminated a valuable food source for marine life. The event was unusual, because it was the second-largest iceberg to calve in the region in 26 months.