This is
actually a neat solution with the conditions and constraints at hand. We will likely find ways of applying this
method in engineering problems. In fact
it points to handling nano tech problems in which perfect uniformity is mostly
too difficult. It may become possible to
order several types of particles using this natural system.
Battery
assembly in particular comes to mind.
At least
we already know that it can be done in nature.
Now we need to discover now nature actually does it.
Strange State of
Matter Found in Chicken's Eye
By Megan Gannon, News
Editor | February 27, 2014 02:19pm ET
This
diagram depicts the spatial distribution of the five types of light-sensitive
cells known as cones in the chicken retina. Scientists have proposed that this
arrangement could be a new state of matter, called disordered hyperuniformity.
Credit:
Courtesy of Joseph Corbo and Timothy Lau, Washington University in St. Louis
Never before seen in biology, a state of
matter called "disordered hyperuniformity" has been discovered in the
eye of a chicken.
This arrangement of
particles appears disorganized over small distances but has a hidden order that
allows material to behave like both a crystal and a liquid.
The discovery came as
researchers were studying cones, tiny light-sensitive cells that allow
for the perception of color, in the eyes of chickens.
For chickens and other birds that
are most active during the daytime, these photoreceptors come in four different
color varieties — violet, blue, green and red — and a fifth type for detecting
light levels, researchers say. Each type of cone is a different size.
These cells are
crammed into a single tissue layer on the retina. Many animals have cones
arranged in an obvious pattern. Insect cones, for example, are laid out in a
hexagonal scheme. The cones in chicken eyes, meanwhile, appear to be in
disarray.
But researchers who
created a computer model to mimic the arrangement of chicken cones discovered a
surprisingly tidy configuration.
Around each cone is a
so-called exclusion region that bars other cones of the same variety from
getting too close. This means each cone type has its own uniform arrangement,
but the five different patterns of the five different cone types are layered on
top of each other in a disorderly way, the researchers say.
"Because the
cones are of different sizes it's not easy for the system to go into a crystal
or ordered state," study researcher Salvatore Torquato, a professor
of chemistry at Princeton University, explained in a statement. "The
system is frustrated from finding what might be the optimal solution, which
would be the typical ordered arrangement. While the pattern must be disordered,
it must also be as uniform as possible. Thus, disordered hyperuniformity is
an excellent solution."
Materials in a state
of disordered hyperuniformity are like crystals in that they keep the density
of particles consistent across large spatial distances, Torquato and
colleagues said. But these systems are also like liquids, because they have the same physical
properties in all directions.
Researchers say this
may be the first time disordered hyperuniformity has been observed in a
biological system; previously it had only been seen in physical systems like liquid helium and simple plasmas.
For chicken eyes, the
researchers speculate this cone arrangement allows the birds to sample incoming
light evenly. Engineers may be able to take inspiration from disordered
hyperuniformity in nature to create optical circuits and light detectors that
are sensitive or resistant to certain light wavelengths, the researchers say.
Their findings were detailed on Feb. 24 in the journal Physical Review E.
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