Interactive computer simulations of genetics, biochemistry, and molecular biology.

This article describes three interactive software simulations targeted to key domains of modern molecular genetics: genetics, biochemistry, and molecular biology. These simulations allow students to deepen their understanding of key principles in these domains by setting up crosses, designing proteins, and designing genes; the simulations then apply these principles to produce results that the students can interpret. Using this software, students can confront their misconceptions and connect these disciplines in a way that is difficult if not impossible without an interactive environment. We present lab exercises that guide the students as they use the software in a series of activities that begin by introducing the tools and build towards more open inquiry. Preliminary evaluation shows that students enjoy the software and that it promotes active engagement and application of the material. The open-source Java software and the relevant lab manuals are available free of charge on line.

Innovative design to prevent reversal of roller blood pump rotation in the event of electromechanical failure: an easy solution to a devastating problem.

Despite the advanced technologies of battery back-up for heart-lung consoles and the availability of system-wide generators, electromechanical failure is still occurring. Several heart-lung machine manufacturers still provide unsafe handcranking devices to use in the case of an emergency while using a roller blood pump. A new design has been engineered to eliminate safety and quality issues for the perfusionist and the patient when the need for handcranking presents itself. A ratchet-style handcranking device was fabricated by means of a steel plate with adjustable pins. The adjustable pins allow for use with different models of the Cobe, Stockert, and Jostra heart-lung consoles, which contain roller pumps with 1800 roller heads. Additional modifications such as a 1:2 transmission and fluorescent markers are also used in the design. This innovative design is an improvement in safety compared with the current handcrank provided by Cobe, Stockert, and Jostra. With this modified handcranking device, accidental reverse rotation of the roller pump head cannot occur. Fluorescent markers will improve visualization of the pump head in low-light situations. The ergonomic design improves efficiency by reducing fatigue. Most importantly, a "safe" safety device will replace the current design provided by these manufacturers, thus improving the quality of care by health care providers.