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 world's biggest iceberg: 19-mile crack in the ice breaking away from Antarctica. An astonishing photograph taken from outer-space illustrates how an iceberg the size of New York is close to breaking off from Antarctica. A 19-mile crack in Pine Island Glacier's ice is clearly visible, leading some scientists to speculate that the world's biggest berg could soon be on the move. The picture, taken by NASA's Terra spacecraft in November 2011 but only released today, shows how the crack is quickly growing.