Paula Noaker Powell

Senior Editor, Laser Focus World

Paula Noaker Powell was a senior editor for Laser Focus World.

In five out of seven humans tested in a recent experiment, scientists at the University of Illinois demonstrated the correlation between hemodynamic signals obtained with frequency-domain near-IR spectroscopy and functional MRI. The arrow in the image indicates the location of the optical center. The yellow color corresponds to the highest area of correlation.

Spectroscopy allows study of brain activity

Oct. 1, 2001

Researchers at the University of Illinois (UI; Champaign, IL) are exploring the use of frequency-domain near-infrared spectroscopy (NIRS) as a noninvasive diagnostic tool to study...

Research

Silicon LED is efficient at room temperature

Paula Noaker Powell

May 1, 2001

Current light-emitting diodes (LEDs) are based on gallium arsenide and are incompatible with silicon-based circuits, which has created a bottleneck for further circuit-miniaturization...

Under nanosecond laser pulsing, an asymmetrical rotaxane molecule based on hydrogen bonding has demonstrated linear motion similar to that of a simple piston. At room temperature in acetonitrile, a macrocyclic bead-like structure locked onto linear thread in the molecule is induced to shuttle to a second location, in a process that takes about 1 µs (similar to the power stroke of a piston). If necessary, after a charge-recombination process lasting roughly 100 µs, the macrocycle can then shuttle back to its original.

Research

Light drives molecular linear motor

Paula Noaker Powell

May 1, 2001

Although researchers have known about the existence of catenane and rotaxane molecules for a couple of decades, it wasn't until the early 1990s that they were first considered...