The proliferation of cell phones that have Internet access is
making it possible for people to find information about the everyday objects
around them, and the likely proliferation of Radio Frequency Identification
(RFID) tags in consumer products would make it easy to link physical objects
with digital information.
Researchers from the Massachusetts Institute of Technology have developed
a hands-free and eyes-free system that allows people to find information
about objects without having to actively scan them, use a keypad, or use
a speech interface in noisy or socially awkward settings.
The system, dubbed ReachMedia,
consists of a bracelet that reads radio frequency identification tags
to detect objects the user is holding, an accelerometer to detect hand
gestures and a cell phone that connects to the Internet, plays sounds
when objects and gestures are recognized, and provides audio information
about the object in hand.
A person could, for example, pick up a book to search for reviews
of the book online. She would hear a sound from her phone indicating information
was available about the book, and would use gestures -- a downward flick
and right and left rotation -- to select or go to the previous or next
menu item of available information.
(ReachMedia: On-the-Move Interaction with Everyday Objects, International
Symposium on Wearable Computers (ISWC'05), Osaka Japan, October 18 - 21,
Nanotube bombs kill cancer
Scientists and medical professionals often use violent imagery
to depict techniques of destroying cancer cells. A type of cancer-killing
carbon nanotubes more than lives up to the language.
Researchers from the University of Delaware have found a way to
detonate nanotubes that have been absorbed by cancer cells to blow
up the cells. The microscopic explosions kill cells containing the
nanotubes but leave surrounding cells intact.
Carbon nanotubes are rolled-up sheets of carbon atoms and are
extremely small. Single-walled carbon nanotubes are typically one nanometer
in diameter, or about 5,000 times smaller than a red blood cell.
The detonation nanotubes are filled with water molecules. When
the nanotubes are exposed to laser light, the water molecules vaporize,
which produces enough pressure to blow up the tubes and any cancer cells
in the immediate vicinity. Other researchers have developed ways of causing
cancer cells to absorb nanotubes, which would be required to use the method
for treating patients.
The explosion method has a distinct advantage over using carbon
nanotubes to deliver anti-cancer drugs to cancer cells, according to the
researchers. The explosions destroy the nanotubes along with the cancer
cells, greatly reducing the risk that the tubes themselves could cause
problems in the body.
Scientists have previously detonated carbon nanotubes, but only
in air (see Light
flashes fire up nanotubes, TRN May 1/8, 2002) by exposure to flashes
(Single Wall Carbon Nanotube Nanobombs Kill Cancer Cells, Nanobiotechnology,
scheduled for publication Fall 2005)
Mesh networks best
There are many kinds of networks, both natural and artificial.
Here's just a sampling: connections among computers, social relationships
among people, and interactions among chemicals used in the body.
With the advent of the easily-studied Internet, scientists have
begun mapping the general properties of networks. Many networks are scale-free,
meaning they have a few heavily-linked central hubs -- large Internet
sites, people with many social contacts, or chemicals involved in many
reactions -- and many more nodes that contain just a few links.
Physicists from the University of Granada in Spain and Boston
University have found that more homogenous entangled
networks, which have no central hubs, are more efficient than scale-free
Entangled networks are more resistant to errors and attacks, more
amenable to search algorithms and provide more efficient communication.
They are, however, not common in the natural world, in part because this
type of structure does not tend to grow naturally over time.
Entangled network structures could make computer networks more
efficient and improve our understanding of how the brain works.
(Entangled Networks, Synchronization, and Optimal Network Topology,
Physical Review Letters, accepted in October 2005)
DNA sensor shines brightly
One way to detect a type of DNA that indicates disease is to form
strands of DNA that contain fluorescent molecules and can combine with
the DNA to be detected. Combined, or hybridized, DNA boosts the energy
of the fluorescent molecules, causing them to emit more light.
Researchers from Johns Hopkins University have dramatically improved
this type of DNA detection with a sensor
whose fluorescent molecules do not emit any light before the disease,
or target, DNA has been captured, and emit a lot of concentrated light
when it is captured. This increases the sensitivity of the sensor 100
The sensor sandwiches the target DNA with a pair of DNA molecules.
One of the pair contains the fluorescent molecule and the other contains
a molecule that links to a layer of molecules coating a nanoscale speck
of semiconductor material. Many captured DNA molecules can link to a single
nanoparticle, concentrating the fluorescent markers. In addition, when
the quantum dot is lit by a laser, it transfers energy to the fluorescent
markers, making them still brighter.
The researchers tested the sensor by detecting DNA from ovarian
tumors. The method could also be used to detect other molecules like proteins
and peptides, and to detect the presence of several types of biological
molecules at once, which could make for more accurate medical diagnosis.
(Single-Quantum-Dot-Based DNA NanoSensor, Nature Materials,
Bits and pieces
A protein from insect joints yields a super
elastic rubber that could make for better medical implants; grids
of radio frequency identification (RFID) tags promise to help
blind people navigate unfamiliar places; bent copper nanowires recover
their original shape when heated, making them potentially useful ingredients
of nanodevices like biosensors.