Peering into the Vortex Core

In an electronic integrated circuit, all of the necessary components are fabricated onto a single semiconductor, which eliminates the need for manual assembly of the individual transistors, capacitors, and resistors. Thorsen et al. (p. 580; see the cover) have now fabricated an analog in a microfluidics system with a set of individually addressable microvalves. Such a system can act as a fluidic random-access memory and can also be used as a series of microreactors in which each reactor can be individually controlled.