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).
A glacier calf, or chunk of ice, measuring nearly five square miles broke away from Greenland's Jakobshavn glacier sometime in August, making it the largest piece to ever break away from one of the world's fastest melting glaciers. glacier, calf, iceberg, jakobshavn, greenland.
The process of icebergs breaking off of a glacier is called calving. Icebergs consist of freshwater ice, pieces of debris, and trapped bubbles of air. The combination of ice and air bubbles causes sunlight shining on the icebergs to color the ice spectacular shades of blue, green, and white.