Carbocations are species bearing a formal + charge on carbon. The have sp2 hybridization and trigonal planar geometry, with an empty p orbital on carbon, perpendicular to the plane containing the substituents (see diagrams shown to the right).
Aortic cross-clamp. An aortic cross-clamp is a surgical instrument used in cardiac surgery to clamp the aorta and separate the systemic circulation from the outflow of the heart. An aortic cross-clamping procedure serves, for example, in the repairing of coarctation of the aorta.
SHOE CLAMPS. The SHOE CLAMP series is single window specialty clamp designed especially for sewing on the sides of soccer shoes. The clamps are build with high strength aluminum and are very heavy duty. The clamping pressure required to hold a stiff leather shoe while sewing over a machine sewing arm is extreme, and the SHOE CLAMP is up to the task.