Strange State of Matter Found in Chicken's Eye
Never before seen in biology, a state of matter called disordered hyperuniformity has been discovered in the eye of a chicken.
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.
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.
Original article on Live Science.
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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.
Nikon held its annual Small World Photomicrography competition, and the winners for 2013 did not disappoint. Judged on both artistic and technical merits, their work brought the very small into dazzlingly sharp focus. Let's zoom in for a look at the competition's top 10 winners. Taking first prize for 2013 was freelance photographer and artist Wim van Egmond, of The Netherlands, for his image of
(marine diatom), a colonial plankton organism. For his winning creation, Egmond, who has more than 20 still images credited as finalists in the Cool World competition over the last decade, used a partial image stack of more than 90 images.
Second place went to Dr. Joseph Corbo, of the Washington University School of Medicine in St. Louis, for his
(painted turtle) retina. He used differential interference contrast microscopy at 400X.
University of Sao Paulo's Dr. Alvaro Esteves Migotto took third place for this 20X darkfield stereomicroscopy marine worm.
The fourth-place Small World prize went to Rogelio Moreno Gill, of Panama City, Panama, for his
, showing the nucleus, mouth and water expulsion vacuoles.
Fifth place was awarded to University of Glasgow's Dr. Kieran Boyle for "Hippocampal neuron receiving excitatory contacts." He used fluorescence and confocal microscopy at 63X.
Small World winner number six was Dorit Hockman, of the University of Cambridge, Cambridge, U.K., for her
(veiled chameleon) embryo showing cartilage (blue) and bone (red), achieved using brightfield microscopy.
Dr. Jan Michels, out of Christian-Albrechts-Universität zu Kiel, Kiel Germany, created "Adhesive pad on a foreleg of
(ladybird beetle)" and took a seventh place Small World prize.
Magdalena Turzańska, eighth-place finisher, of the University of Wrocław, Wrocław, Poland, was honored for
(a leafy liverwort, bryophyte plant) and cyanobacteria.
Mark A. Sanders, of Minneapolis, Minn., took ninth place for his insect wrapped in a spider web, which used confocal, autofluorescence image stacking at 85X.
Rounding out the top 10 of Nikon's Small World winners was Ted Kinsman, Department of Imaging and Photo Technology, Rochester Institute of Technology, Rochester, N.Y. He was honored for this thin section of a dinosaur bone preserved in clear agate. To learn about other Small World winners and see more great images, visit the competition