September/October 2010

A dying cancer patient is in excruciating pain. The doctor must choose between alleviating pain or shortening life: the painkillers that would help the patient could kill them quicker than the cancer. Suddenly the Hippocratic Oath may not seem guidance enough.

According to Clive Seale’s research, doctors dealing with death, despite their best efforts to act objectively, may turn to faith to make such ethically-challenging decisions.

Seale, a medical sociologist with Queen Mary University of London, surveyed doctors of varying specialties within Great Britain, asking them to report, among other things, on both the care of their last patient who died and their religious beliefs.

Questions covered a number of moral gray areas in end-of-life care, from withholding risky treatments from an elderly stroke patient to assisted suicide.

For his analysis, Seale lumped all of these types of decisions together to facilitate a simple yes/no comparison between doctors who made decisions that shortened a patient’s life and those who did not. read more »

The sensor is sensitive enough to easily detect this Peruvian butterfly
(Chorinea faunus) with transparent wings and red-tipped tails,
positioned on a sheet of the sensors.
Credit: Linda Cicero, Stanford University News Service

There’s nothing quite like human touch. Or is there? In September, two groups of California researchers introduced artificial skins that use electricity to sense even the slightest stroke. It’s not the first time electricity has been used in artificial skins, but the new ones are much quicker to conduct current than older efforts. At less than a millimeter thick, the flexible, stretchable sheets could someday be useful in giving prosthetic devices the sensation of touch.

The thin sheets, reported in Nature Materials, can sense pressure changes up to twenty times subtler than previous faux skins. They can even register the tiny touch of a fly’s feet, all in a tenth of a second. This is because “they are basically able to build up more electricity” than older models, says Benjamin Tee, who worked on the Stanford University skins.

To make the skins, Stanford researchers molded mini pyramid shapes onto a thin rubber sheet and attached electrodes—metal strips that conduct charge—to either side. When the pyramid shapes squish under pressure, electricity flow grows, making pressure to the skin register as a difference in touch. read more »

PET film with microstructured PDMS on aluminium metal lines
Adapted by permission from Macmillan Publishers Ltd:
Nature Materials doi:10.1038/nmat2861, copyright 2010

Mummies, look alive: the same triangular shapes in which you were buried for thousands of years—pyramids—are now an essential element in the scientific push for better artificial skin.

The Bao Research Group at Stanford University just concluded a five-year effort to develop an “e-skin” that mimics the sensitivity and flexibility of human skin. While artificial skin can’t be grafted (yet), the research, funded by the Department of Defense, could vastly improve prosthetics and robotic touch.

The unparalleled elasticity and sensitivity of the new material comes from its rubbery inner layer, which is sandwiched between two thin layers of electrodes. Less than a millimeter thick, this silicate material is made using a substance called Polydimethylsiloxane (PDMS)—the stuff that gives Silly Putty its bounce and elasticity—and which stores electric charge. read more »

This artist’s concept illustrates the two Saturn-sized planets
discovered by NASA’s Kepler mission.
Image credit: NASA/Ames/JPL-Caltech

Nearly 2,200 light-years away, a planet just one-and-a-half times the size of Earth may be orbiting the star Kepler-9. Though it is dwarfed by its two Saturn-sized companions, this small object could be the most important part of a newly discovered system of planets.

Kepler-9 is one of roughly 150,000 stars being monitored by the Kepler mission in an attempt to find earth-like planets orbiting sun-like stars, and perhaps, eventually, life on one of those planets.

Since March 2009, the Kepler spacecraft has been identifying these possible exoplanets by measuring differences in the amount of light given off by a star. A star grows dimmer when an object, such as a planet, crosses its path. Researchers can then determine the size of the object from the amount the star’s brightness changes.

Even multiple planets around a single star can be detected, because each planet takes a unique amount of time to complete an orbit. Yet, the gravitational tug the planets have on each other makes a multi-planet system more difficult to measure. read more »