Monovalent, reduced-size quantum dots for imaging receptors on living cells
We describe a method to generate monovalent quantum dots (QDs) using agarose gel electrophoresis. We passivated QDs with a carboxy-terminated polyethylene-glycol ligand, yielding particles with half the diameter of commercial QDs, which we conjugated to a single copy of a high-affinity targeting moiety (monovalent streptavidin or antibody to carcinoembryonic antigen) to label cell-surface proteins. The small size improved access of QD-labeled glutamate receptors to neuronal synapses, and monovalency prevented EphA3 tyrosine kinase activation.
Barack Obama said his plan to end the Iraq war was unchanged and he was puzzled by the sharp reaction to his statement that he might "refine" his timetable for withdrawing U.S. combat troops.
AFP - The United States military wanted to test deadly nerve gases on Australian troops in a remote area of far north Queensland in the 1960s but Canberra refused, a report said Sunday.
