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.
One-Hand Clamp. The one-hand clamp is a special type of bar clamp that can be applied with one hand by squeezing a trigger. As the trigger is squeezed, the jaw closes, and more squeezes equals more pressure. They also feature a quick-release mechanism.