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There’s locks to
learn about hair
By Rachel Ehrenberg
Scientists are closer to understanding
the forces that conspire to create a bad
hair day, thanks to a new technique that
allows researchers to measure friction
and other forces between two hairs.
Understanding such hair-on-hair
interactions may lead to new cosmetic
products for taming hair or to more realistic computer-animated coifs. It also
may help researchers better understand
interactions among other fibers, such as
those used in clothing or bandages.
“ What is interesting about hair — while
it has been with us for a long time, it
is still very unknown,” says Gustavo
Luengo, a research scientist with L’Oréal
in Paris. Luengo and coauthors Mark
Rutland and Hiroyasu Mizuno of KTH
Royal Institute of Technology in Stock-
holm describe the new work online
November 30 in Langmuir.
Hornet pigment can drive solar cell
an insect’s light-harvesting apparatus intrigues scientists
By Rachel Ehrenberg
The possibility that a hornet might
be harvesting sunlight for energy has
researchers abuzz. Scientists have constructed an electricity-generating solar
cell using a pigment from the oriental
hornet, a team reports in the December
Naturwissenschaften — but much more
evidence would be needed to link solar
input to power output in the living beast.
Oriental hornets (Vespa orientalis)
spend their days clearing soil from their
underground nests. While many wasps
would go about such business in the
cooler morning hours, previous research
led by the late Jacob Ishay of Tel Aviv
University noted that this hornet’s activity peaks in sweltering midday. Experiments also showed that shining a light
on the hornets generated voltage differences across their hard exoskeletons.
The yellow stripe on the backside of
an oriental hornet (shown) contains a
pigment capable of capturing light.
These and other finds suggested that
the hornets were maximizing exposure
to sunlight. So Ishay’s student, Marian
Plotkin, decided to further investigate
the brown and yellow pigment on the
insect’s cuticle.
Examination of the striped patch on the
hornet’s backside revealed a microstructure that traps incoming light. And when
Plotkin and his colleagues extracted a yellow pigment called xanthopterin from the
hornet’s outer shell and plopped it into a
solar cell that uses dyes to absorb light,
the device squeaked out some electricity.
The find is interesting but not surprising, says Andrew Parker of the Natural
History Museum in London. The skins
and shells of organisms from butterflies
to diatoms can have complex microstructures that manipulate light.
The researchers have a long way to go
to demonstrate that the oriental wasp
is solar-powered, says Parker. The team
hasn’t shown that xanthopterin is linked
to production of ATP, the energy-storing
molecule of cells. And any number of pigments might eke out some electricity if
stuck in a dye-sensitized solar cell.
Even if it turns out that this wasp uses
the sun in a more ordinary manner, the
idea that insects might get an energy
buzz from sunlight isn’t so farfetched.
“Virtually everything that’s been engineered in the physics world,” Parker
says, “turns up in nature.”
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