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.
Denaliâs Howl is the white-knuckle account of one of the most deadly climbing disasters of all time. In 1967, twelve young men attempted to climb Alaskaâs Mount McKinleyâknown to the locals as Denaliâone of the most popular and deadly mountaineering destinations in the world. Only five survived.