In 1952, the legendary British mathematician and cryptographer Alan Turing proposed a model, which assumes formation of complex patterns through chemical interaction of two diffusing reagents. Russian scientists managed to prove that the corneal surface nanopatterns in 23 insect orders completely fit into this model. Their work is published in the ("Diverse set of Turing nanopatterns coat corneae across insect lineages"). 
The diversity of corneal nanostructural patterns among arthropod groups: (AandB) Corneal nanostructures of Trichoptera. Merged as well as undersized nipples in an irregular nipple array of the Phryganeidaefamily (A) and maze-like nanocoating of the Limnephilidae family (B). (C) Clearly expressed parallel strands in a true spider. (D) Dimpled nanopattern of an earwig (Dermaptera). (E) Nipples merging into maze on stonefly (Plecoptera) corneae. (FandG) Merging of individual Dipteran nipples into parallel strands and mazes: full merging of nipples into strands and mazes on the entire corneal surface in Tabanidae (F); partial merging of nipples in the center of Tipulidae cornea into elongated protrusions and then complete fusion into an array of parallel strands near the ommatidial edge (G). (H) Merging of individual burrows and dimples into a maze-like structure on bumblebee (Apidae, Hymenoptera) corneae. All image dimensions are 5×5?m, except forH, which is 3×3?m. Surface height in nanometers is indicated by the color scale shown next to 2-D images. (Image: Artem Blagodatsky et al) (click on image to enlarge) The work was done by a team working in the Institute of Protein Research of the Russian Academy of Sciences, (Pushchino, Russia) and the Department of Entomology at the Faculty of Biology of the Lomonosov Moscow State University. It was supervised by Professor Vladimir Katanaev, who also leads a lab in the University of Lausanne, Switzerland. Artem Blagodatskiy and Mikhail Kryuchkov performed the choice and preparation of insect corneal samples and analyzed the data. Yulia Lopatina from the Lomonosov Moscow State University played the role of expert entomologist, while Anton Sergeev performed the atomic force microscopy. The initial goal of the study was to characterize the antireflective three-dimensional nanopatterns covering insect eye cornea, with respect to the taxonomy of studied insects and to get insight into their possible evolution path. The result was surprising as the pattern morphology did not correlate with insect position on the evolutionary tree. Instead, Russian scientists have characterized four main morphological corneal nanopatterns as well as transition forms between them, omnipresent among the insect class. Another finding was that all the possible forms of the patterns directly matched to the array of patterns predicted by the famous Turing reaction-diffusion model published in 1952, what Russian scientists confirmed not by mere observation, but by mathematical modeling as well. The model assumes formation of complex patterns through chemical interaction of two diffusing reagents. The analysis of corneal surface nanopatterns in 23 insect orders has been performed by means of atomic force microscopy with resolution up to single nanometers. "This method allowed us to drastically expand the previously available data, acquired through scanning electron microscopy; it also made possible to characterize surface patterns directly, not based upon analysis of metal replicas. When possible, we always examined corneae belonging to distinct families of one order to get insight into intra-order pattern diversity," Artem Blagodatskiy says. The main implication of the work is the understanding of the mechanisms underlying the formation of biological three-dimensional nano-patterns, demonstrating the first example of Turing reaction-diffusion model acting in the bio-nanoworld. Interestingly, the Turing nanopatterning mechanism is common not only for the insect class, but also for spiders, scorpions and centipedes in other words - universal for arthropods. Due to the antireflective properties of insect corneal nanocoatings, the revealed mechanisms are paving the way for design of artificial antireflective nanosurfaces. "A promising future development of the project is planned to be a genetic analysis of corneal nanopattern formation on platform of a well studied Drosophila melanogaster (fruitfly) model. The wild-type fruitflies possess a nipple array type nanocoating on their eyes," Artem Blagodatskiy summarized. Different combinations of overexpressed and underexpressed proteins known to be responsible for corneal development in Drosophila may alter the nipple pattern to another pattern type and thus shed the light on chemical nature of compounds, forming the Turing-type structures upon insect eyes. Revealing of proteins and\or other agents responsible for nanopattern formation will be a direct clue to artificial design of nanocoatings with desired properties. Another direction of project development will be the comparison of antireflective features of different types of characterized nanocoatings.
read more "Diverse set of Turing nanopatterns coat corneae of insects"
The diversity of corneal nanostructural patterns among arthropod groups: (AandB) Corneal nanostructures of Trichoptera. Merged as well as undersized nipples in an irregular nipple array of the Phryganeidaefamily (A) and maze-like nanocoating of the Limnephilidae family (B). (C) Clearly expressed parallel strands in a true spider. (D) Dimpled nanopattern of an earwig (Dermaptera). (E) Nipples merging into maze on stonefly (Plecoptera) corneae. (FandG) Merging of individual Dipteran nipples into parallel strands and mazes: full merging of nipples into strands and mazes on the entire corneal surface in Tabanidae (F); partial merging of nipples in the center of Tipulidae cornea into elongated protrusions and then complete fusion into an array of parallel strands near the ommatidial edge (G). (H) Merging of individual burrows and dimples into a maze-like structure on bumblebee (Apidae, Hymenoptera) corneae. All image dimensions are 5×5?m, except forH, which is 3×3?m. Surface height in nanometers is indicated by the color scale shown next to 2-D images. (Image: Artem Blagodatsky et al) (click on image to enlarge) The work was done by a team working in the Institute of Protein Research of the Russian Academy of Sciences, (Pushchino, Russia) and the Department of Entomology at the Faculty of Biology of the Lomonosov Moscow State University. It was supervised by Professor Vladimir Katanaev, who also leads a lab in the University of Lausanne, Switzerland. Artem Blagodatskiy and Mikhail Kryuchkov performed the choice and preparation of insect corneal samples and analyzed the data. Yulia Lopatina from the Lomonosov Moscow State University played the role of expert entomologist, while Anton Sergeev performed the atomic force microscopy. The initial goal of the study was to characterize the antireflective three-dimensional nanopatterns covering insect eye cornea, with respect to the taxonomy of studied insects and to get insight into their possible evolution path. The result was surprising as the pattern morphology did not correlate with insect position on the evolutionary tree. Instead, Russian scientists have characterized four main morphological corneal nanopatterns as well as transition forms between them, omnipresent among the insect class. Another finding was that all the possible forms of the patterns directly matched to the array of patterns predicted by the famous Turing reaction-diffusion model published in 1952, what Russian scientists confirmed not by mere observation, but by mathematical modeling as well. The model assumes formation of complex patterns through chemical interaction of two diffusing reagents. The analysis of corneal surface nanopatterns in 23 insect orders has been performed by means of atomic force microscopy with resolution up to single nanometers. "This method allowed us to drastically expand the previously available data, acquired through scanning electron microscopy; it also made possible to characterize surface patterns directly, not based upon analysis of metal replicas. When possible, we always examined corneae belonging to distinct families of one order to get insight into intra-order pattern diversity," Artem Blagodatskiy says. The main implication of the work is the understanding of the mechanisms underlying the formation of biological three-dimensional nano-patterns, demonstrating the first example of Turing reaction-diffusion model acting in the bio-nanoworld. Interestingly, the Turing nanopatterning mechanism is common not only for the insect class, but also for spiders, scorpions and centipedes in other words - universal for arthropods. Due to the antireflective properties of insect corneal nanocoatings, the revealed mechanisms are paving the way for design of artificial antireflective nanosurfaces. "A promising future development of the project is planned to be a genetic analysis of corneal nanopattern formation on platform of a well studied Drosophila melanogaster (fruitfly) model. The wild-type fruitflies possess a nipple array type nanocoating on their eyes," Artem Blagodatskiy summarized. Different combinations of overexpressed and underexpressed proteins known to be responsible for corneal development in Drosophila may alter the nipple pattern to another pattern type and thus shed the light on chemical nature of compounds, forming the Turing-type structures upon insect eyes. Revealing of proteins and\or other agents responsible for nanopattern formation will be a direct clue to artificial design of nanocoatings with desired properties. Another direction of project development will be the comparison of antireflective features of different types of characterized nanocoatings.
All-optical data memory: Ultra-short light pulses make the GST material change from crystalline to amorphous and back. Weak light pulses read out the data. (Image: C. Rios/Oxford University) Light determines the future of information and communication technology: With optical elements, computers can work more rapidly and more efficiently. Optical fibers have long since been used for the transmission of data with light. But on a computer, data are still processed and stored electronically. Electronic exchange of data between processors and the memory limits the speed of modern computers. To overcome this so-called von Neumann bottleneck, it is not sufficient to optically connect memory and processor, as the optical signals have to be converted into electric signals again. Scientists, hence, look for methods to carry out calculations and data storage in a purely optical manner. Scientists of KIT, the University of Münster, Oxford University, and Exeter University have now developed the first all-optical, non-volatile on-chip memory. “Optical bits can be written at frequencies of up to a gigahertz. This allows for extremely quick data storage by our all-photonic memory,” Professor Wolfram Pernice explains. Pernice headed a working group of the KIT Institute of Nanotechnology (INT) and recently moved to the University of Münster. “The memory is compatible not only with conventional optical fiber data transmission, but also with latest processors,” Professor Harish Bhaskaran of Oxford University adds. The new memory can store data for decades even when the power is removed. Its capacity to store many bits in a single cell of a billionth of a meter in size (multi-level memory) also is highly attractive. Instead of the usual information values of 0 and 1, several states can be stored in an element and even autonomous calculations can be made. This is due to so-called phase change materials, novel materials that change their optical properties depending on the arrangement of the atoms: Within shortest periods of time, they can change between crystalline (regular) and amorphous (irregular) states. For the memory, the scientists used the phase change material Ge2Sb2Te5 (GST). The change from crystalline to amorphous (storing data) and from amorphous to crystalline (erasing data) is initiated by ultrashort light pulses. For reading out the data, weak light pulses are used. Permanent all-optical on-chip memories might considerably increase future performance of computers and reduce their energy consumption. Together with all-optical connections, they might reduce latencies. Energy-intensive conversion of optical signals into electronic signals and vice versa would no longer be required.
In coherent diffraction imaging, extreme ultraviolet light scatters off the target and produces a diffraction pattern. A computer analyzes the pattern to reconstruct an image of the target material. (Image: Dr. Michael Zürch, Friedrich Schiller University Jena, Germany) The researchers' wanted to improve on a lensless imaging technique called coherent diffraction imaging, which has been around since the 1980s. To take a picture with this method, scientists fire an X-ray or extreme ultraviolet laser at a target. The light scatters off, and some of those photons interfere with one another and find their way onto a detector, creating a diffraction pattern. By analyzing that pattern, a computer then reconstructs the path those photons must have taken, which generates an image of the target material -- all without the lens that's required in conventional microscopy. "The computer does the imaging part -- forget about the lens," explained Michael Zürch, Friedrich Schiller University Jena, Germany and lead researcher. "The computer emulates the lens." Without a lens, the quality of the images primarily depends on the radiation source. Traditionally, researchers use big, powerful X-ray beams like the one at the SLAC National Accelerator Laboratory in Menlo Park, California, USA. Over the last ten years, researchers have developed smaller, cheaper machines that pump out coherent, laser-like beams in the laboratory setting. While those machines are convenient from the cost perspective, they have drawbacks when reporting results. The table-top machines are unable to produce as many photons as the big expensive ones which limits their resolution. To achieve higher resolutions, the detector must be placed close to the target material -- similar to placing a specimen close to a microscope to boost the magnification. Given the geometry of such short distances, hardly any photons will bounce off the target at large enough angles to reach the detector. Without enough photons, the image quality is reduced. Zürch and a team of researchers from Jena University used a special, custom-built ultrafast laser that fires extreme ultraviolet photons a hundred times faster than conventional table-top machines. With more photons, at a wavelength of 33 nanometers, the researchers were able to make an image with a resolution of 26 nanometers -- almost the theoretical limit. "Nobody has achieved such a high resolution with respect to the wavelength in the extreme ultraviolet before," Zürch said. The ultrafast laser also overcame another drawback of conventional table-top light sources: long exposure times. If researchers have to wait for images, they can't get real-time feedback on the systems they study. Thanks to the new high-speed light source, Zürch and his colleagues have reduced the exposure time to only about a second -- fast enough for real-time imaging. When taking snapshots every second, the researchers reached a resolution below 80 nanometers. The prospect of high-resolution and real-time imaging using such a relatively small setup could lead to all kinds of applications, Zürch said. Engineers can use this to hunt for tiny defects in semiconductor chips. Biologists can zoom in on the organelles that make up a cell. Eventually, he said, the researchers might be able to cut down on the exposure times even more and reach even higher resolution levels. About the Presentation The presentation, "Approaching the Abbe Limit in the Extreme Ultraviolet: Ultrafast Imaging Using a Compact High Average Power High Harmonic," by Michael Zürch, will take place from 13:00 - 14:45, Thursday, 22 October 2015, in The Fairmont Hotel, San Jose, California, USA. Media Registration: A media room for credentialed press and analysts will be located on-site in The Fairmont Hotel, 18-22 October 2015. Media interested in attending the event should register on the FiO website media center: Media Center.