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Image: Robert Scoble, Flickr.com
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Issue no. 14, 2012
Published: May 11, 2012 |
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 Magnetic bacteria create a biological hard drive | | Middle ear MEMS microphone could restore hearing | | Silicon 'prism' bends gamma rays | | Silicon cracks could make a lab-on-a-chip | | Roulette beater spills physics behind victory | | Does literature impact what scientists study? |
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| Magnetic bacteria create a biological hard drive |
Hard drives store data on discs coated with a metallic film divided into
tiny magnetic regions, each of which stores a single bit - the more
regions you can squeeze on to a disc, the bigger the capacity. Now, a
team at the University of Leeds, UK, have borrowed a trick from nature
to build a new kind of hard drive.
Certain strains of bacteria absorb iron to make magnetic nanoparticles
that let them navigate using the Earth's magnetic field. The team have
extracted the protein behind this process and used it to create magnetic
patterns that can store data.
Hard drives are usually made by 'sputtering', in which clouds of argon
ions are fired at a sheet of magnetic material, knocking off particles
which are deposited as a thin film on a disc. Groups of these particles,
called grains, form the magnetic regions on the drive, with around 100
grains corresponding to one bit.
Instead of granular media, the Leeds team produce bit-patterned media.
They start with a gold surface coated in chemicals in a chessboard
pattern so that one set of squares binds proteins and the other repels
them. They then apply the magnet-producing protein and coat the surface
with an iron solution, which the protein-covered squares convert into
magnetic material.
Each magnetic square in bit-patterned media can store one bit. Each
square the team have so far produced is around 20 micrometres wide, far
too bulky to store data with a density comparable to today's hard
drives. They now plan to test out nano-sized squares, much closer to
existing drive density. Eventually, they hope to create a disk with a
single iron particle per square, which will store as much as 1 terabyte
of data per square inch - far beyond the capability of most hard drives. |
| New Scientist / Small
May 09, 2012 |
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| Middle ear MEMS microphone could restore hearing |
Researchers at the University of Utah have developed a MEMS microphone
that can be implanted in the middle ear to restore hearing and requires
no clunky external electronics. The device improves upon conventional
cochlear implants, which require a microphone and related electronics to
be worn outside the head, creating reliability issues and social stigma.
Sound normally moves into the ear canal and makes the eardrum vibrate.
At a structure known as the umbo, the eardrum connects to a chain of
three tiny bones-the hammer, anvil and stirrup-that vibrate. The stirrup
touches the cochlea, the inner ear's fluid-filled chamber, and hair
cells on the cochlea's inner membrane move, triggering the release of a
neurotransmitter chemical that carries the sound signals to the brain.
In profoundly deaf people the hair cells don't work. So in a traditional
cochlear implant, the microphone, signal processor and transmitter coil,
which are worn outside the head, send signals to a receiver-stimulator
under the skin, which then sends the signals to electrodes implanted in
the cochlea and stimulates auditory nerves. The ear canal, eardrum and
hearing bones are bypassed.
The system developed in Utah moves all the external components inside
the body. Sound moves through the ear canal to the eardrum, which
vibrates as it does normally. An accelerometer is attached to the umbo
to detect the vibration. The accelerometer is also attached to a chip,
and together they serve as a microphone that picks up the sound
vibrations and converts them into electrical signals sent to the
electrodes in the cochlea.
The package is glued to the umbo so the accelerometer vibrates in
response to eardrum vibrations. The moving mass generates an electrical
signal that is amplified by the chip, which then connects to the a
speech processor and stimulator wired to the electrodes in the cochlea. |
| IEEE Transactions on Biomedical Engineering
May 03, 2012 |
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| Silicon 'prism' bends gamma rays |
Physicists have always believed that it would be impossible to create a
practical lens that could focus gamma rays like light. Now, however, an
unexpected discovery suggests gamma-ray focusing is indeed possible.
When electromagnetic radiation travels through a medium, its speed is
given by the index of refraction of the material. When radiation goes
from one medium to another, the change in the index of refraction causes
its path to bend - and this forms the basis of classical optics. For
X-rays, the index of refraction is defined by Rayleigh scattering.
While physicists have used Rayleigh scattering to focus X-rays, the
strength of the effect drops off as the inverse square of the X-ray
energy. This means that at high X-ray energies - and on into low
gamma-ray energies - the radiation is not bent enough for a lens to work
effectively. One way round this is to put the radiation through a large
number of successive lenses. However, no lens is perfectly transparent
and at higher energies the large number of lenses needed would result in
practically all of the radiation being absorbed.
According to classical physics and conventional quantum physics, this
trend should continue at higher energies. This is what researchers at
Ludwig Maximilians University in Munich, Germany, and at the Institut
Laue-Langevin in Grenoble, France, set out to measure in silicon. But
instead they discovered that the exact opposite occurs - the index of
refraction starts to make a comeback at energies greater than about 700
keV. What is more, while the index of refraction is negative for X-rays,
it becomes positive for gamma rays.
Possible applications are medical imaging where gamma rays could be used
to track lithium in the brains of patients being treated for bipolar
disorders. The discovery could also result in a better fundamental
understanding of how light interacts with matter. |
| PhysicsWorld / Physical Review Letters
May 09, 2012 |
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| Silicon cracks could make a lab-on-a-chip |
Sometimes you need to break things to fix them. Researchers from of Ewha
Womans University in Seoul, South Korea, have developed a way of
controlling patterns of cracks in silicon chips to create atomic-scale
features such as nano-channels.
The researchers etched a pattern of notches into a silicon wafer and
deposited a layer of silicon nitride on top. The notches set up stresses
within the nitride layer that cause it to crack in line with the
underlying wafer's crystal structure, which acts as a guide.
The nano-cracks could serve as channels for lab-on-a-chip type
applications such as single-molecule sensing. Electron beams are
currently used to etch atomic-scale patterns, but this is time-consuming
and expensive. By contrast, cracks form instantaneously, according to
the scientists. |
| New Scientist / Nature
May 09, 2012 |
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| Roulette beater spills physics behind victory |
In the 1970s, Doyne Farmer used the world's first wearable computer to
beat roulette tables in Nevada, but never revealed how he did it. Now he
has decided to break his long silence after a pair of researchers
developed and published their own method of beating the house.
Farmer's paper is a response to recent research by Michael Small from
the University of Western Australia in Perth and Michael Tse from Hong
Kong Polytechnic University. They demonstrate that with a few
measurements and a small computer or smartphone, you can indeed tip the
odds in your favour. The trick is to record when the ball and a set part
of the rotating wheel both pass a chosen point.
Their model divides the game into two parts: what happens while the ball
rolls around the rim of the wheel and then falls, which is highly
predictable, and what happens after the ball starts bouncing around,
which is chaotic and hard to predict. Because the first part is
predictable, Small and Tse were able to calculate roughly where the ball
would begin its erratic bouncing and therefore in which part of the
wheel it was more likely to land.
Using a subtle counting device, the pair was able to predict in which
half of the wheel the ball would fall in 13 out of 22 trials. In three
trials, the model predicted the exact pocket. That is equivalent to
taking the odds from 2.7% in the house's favour to 18% in the player's
favour. They confirmed their technique via 700 trials using an automated
camera system, which would be too conspicuous to use in a casino.
Farmer says Small and Tse's model is very similar to his own, except
that they assume that the main force slowing the ball down is friction
with the rim, whereas he found that it is air resistance. Small is
confident that casinos are aware of the trick. Casinos could guard
against it by closing bets before the wheel has rotated enough times for
sufficient measurements. |
| New Scientist
May 10, 2012 |
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| Does literature impact what scientists study? |
How does art inspire science? It may seem a difficult question to answer
with any empirical evidence, but in a new research project Scottish
scientists aim to do just that.
Launched yesterday, What Scientists Read? will aim to find out what
influence literature has on scientists and the decisions they make.
Asking questions like 'how does reading literature affect scientific
thought and practice?' and 'does reading literature affect the career
decision to become a scientist?', the project team will conduct
interviews with scientists in Scotland to try to unravel the influence
on science of the creative arts.
Fear not, though. Even if you’re ruled out of the interviews due to
geographical disadvantages you can still take part in the study. The
project's website hosts a forum where any scientist can go and add to
the discussion. See http://www.whatscientistsread.com. |
| New Scientist
May 10, 2012 |
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