EVENTS, ADVANCES, AND NEWS
■ BY JEFF ECKERT
BUBBLES ARE BACK?
PHOTO COURTESY OF MANU PRAKASH.
stances that don’t mix (e.g., oil and
water, wine and whiskey). The team has
demonstrated, at least in theory, all elements needed for any new logic family,
including gates, memories, amplifiers,
and oscillators. One main drawback at
this point, however, is speed — they run
about 0.1 percent of the speed of a
typical microprocessor, so a computer
driven by them would have slightly
more power than a Commodore
VIC- 20. But the devices may also prove
useful in programmable print heads
and various medical applications.
wide), with a layer of the switches
sandwiched between the wires.
Commercial use of the concept is
still a few years off, but one of the collaborators noted, “Our goal was not to
demonstrate a robust technology; the
memory circuit we have reported on
is hardly that. Instead, our goal was to
demonstrate that large-scale, working
electronic circuits could be constructed at a density that is well beyond (10-
15 years) where many of the most
optimistic projections say is possible.”
■ MIT researchers have developed
a computer chip that runs on
microbubbles like these.
BUT MAYBE MOLECULES
ARE MORE MIRACULOUS
ON THE WAY
It looks a little like a damaged
compound eye from a mechanical
insect, but what you’re really looking
at is a new device that could derive —
among other things — computing
capabilities from microfluid bubbles. A
team of scientists from MIT’s Center
for Bits and Atoms (http://cba.mit.
edu/) recently reported the development of “bubble logic,” which “merges
chemistry with computation, allowing
a digital bit to carry a chemical payload.” This should not be mistaken for
the bubble memories of a few decades
ago, which showed promise but
ultimately were too slow and expensive
for widespread commercialization.
Although bubble logic functions
in a manner that is analogous to electronics, what you really have is a tiny
chip in which nanoliters of fluid flow
from one part to the other and undergo controlled chemical reactions.
Instead of using electrical states to
indicate a 1 or a 0, it bases its logic on
the presence or absence of a bubble.
The demonstrated approach
employs nitrogen bubbles in water, but
you can use pretty much any two sub-
8 April 2007
PHOTO COUR TESY OF
J. FRASER STODDAR T
CHEMISTRY GROUP, UCLA.
■ These switches store information in
an ultra-dense 160 kilobit memory
made up of a 400 x 400 grid of
Approaching high logic density
from a different direction is a project from UCLA ( www.ucla.edu), where
researchers have created a dense
memory device, said to be about the
size of a white blood cell, that could be
an important step toward the creation
of molecular computers to replace
today’s silicon-based technology.
The switches (right side of illustration) are made up of a molecular ring
that encircles the dumbbell-shaped
molecule. When the switch is
triggered, the ring slides between two
locations to control conductivity. The
present device contains 160 kbits that
are arranged on a grid (left side of
illustration) of nanowires (400 silicon
crossed by 400 titanium, each 16 nm
The notoriously bad handwriting of physicians has been a
joke for as long as anyone can
remember, but when it comes to
writing prescriptions, some of the
humor disappears. According to the
National ePrescribing Safety Initiative
(NEPSI, www.nationaleRx.com), medication errors injure at least 1.5 million
Americans and kill 7,000 every year.
Although many of these are unrelated
to penmanship and are caused by common adverse reactions and such, it does
appear that switching US doctors over
to electronic prescription filing could
improve the situation. Unfortunately,
fewer than 1 in 5 MDs have adopted it,
so NEPSI, a coalition of health care and
technology companies too numerous
to mention, is now providing such
capabilities free of charge.
The backbone of the NEPSI
program is eRx NOW™ — web-based
software from Allscripts ( www.all
scripts.com) powered by the same
engine used today by more than
20,000 physicians already. Designed
for physicians in solo practice or small