Physics tip sheet #11 - M...( 1) Experimental control of heart rhythm...),Health

Alternans is a periodic heart rhythm that can cause fibrillation and heart attacks. An experimental study in bullfrog hearts showed that alternans was reliably suppressed and prevented from re-occurring. Electrical activity in the heart was monitored and a feedback cycle applied small electrical impulses to the heart. The authors suggest that a modification of this procedure may be able to maintain normal heart function in humans.

Journal article: http://link.aps.org/abstract/PRL/v88/e198102

2) How drops drip
A. D'Innocenzo, F. Paladini, and L. Renna
Physical Review E (Print issue: May 2002)

Understanding dripping has engineering applications from control of ink-jet printers to biochip arrayers. Dripping shows a wide variety of characteristics from periodic to chaotic but has never been clearly connected with the physical properties of a system. A set of experiments explores the connections between nozzle sizes, nozzle shapes, flow rates and dripping patterns. The researchers found that for large nozzles, the dripping patterns are mainly dependent on flow rates. For small nozzles, the patterns depend on the shape of the nozzle such as whether it is flat or beveled. By reducing the diameter and wall thickness of nozzles, satellite drops (small drops accompanying larger drops) are practically eliminated.

Journal article: http://link.aps.org/abstract/PRE/v65/e056208

3) Hydrogen at extremely high pressures
M. Knudson, R. Cauble
APS April Meeting/Physics News Update

Hydrogen at extremely high pressures, upwards of a million times that on the Earth's surface, can now be produced in physics laboratories. Understanding hydrogen's behavior under such extreme conditions
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Contact: David Harris
harris@aps.org
301-209-3238
American Physical Society
1-May-2002