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This week the Alchemist catches sight of nanoscopic Turing patterns, learns about supramolecular polymer control, hears about acoustic tweezers for improving protein X-ray studies, spreads out a sheet of penta-graphene, theoretically, and digs in a green approach to agricultural fertilizer. Finally, a grant for homeland security in Houston.




British mathematician Alan Turing, perhaps most famous as the father of modern computing and a veteran of the World War II codebreaking centre at Bletchley Park, was also fascinated by how animals get their pigment patterns, the zebra its stripes, the leopard its spots, for instance. His chemical explanation of the emergence of such pelt patterns remains relevant today and has been extrapolated to other areas of animal development. Now, a collaboration between researchers in Denmark and Poland has revealed that the chaotic fluctuations of atoms and molecules can also give rise to Turing patterns on the nanoscopic scale. "So far, no-one has even studied the possibility of the formation of Turing patterns by single atoms or molecules. However, our results show that Turing nanostructures may exist. And since this is the case, we will be able to find very specific applications for them in nanotechnology and materials science," explains Bogdan Nowakowski of the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw.





Researchers from the RIKEN Center for Emergent Matter Science have developed a new approach for constructing supramolecular polymers with electronic and other desirable properties in a stepwise and highly selective manner. The work builds on the accidental discovery that corannulene, while usually stable, can undergo polymerization in a self-assembly process if an initiator is added to its solvent. If the initiator is removed, the polymerization stops, and product chirality depends on initiator chirality the team found. The team was also able to disassemble their polymers with near 100 percent efficiency.





Fragile proteins can now be studied with X-ray crystallography thanks to the application of microfluidic acoustic "tweezers" that use sound waves to hold the protein in the path of an X-ray beam for diffraction analysis. Tony Jun Huang and colleagues Penn State University explain that acoustic tweezers sidestep the difficulties in manually mounting a crystal using a microscope and a needle-like cryoloop to hold microscopic samples. Acoustic tweezers promise to improve efficiency and throughput of serial crystallography methods and more conventional data collection approaches, the team reports.





An international collaboration between scientists in China, Japan and the USA suggests that a pentagonal form of graphene might be possible. The material would not be perfectly flat but would nevertheless resemble the "chicken wire" structure of graphene with its hexagons of carbon atoms but where they form pentagons instead. "Carbon is an amazing material showing many faces [pardon the pun] - from graphite to graphene, nanotubes, and fullerenes where hexagons are the basic building blocks," Qian Wang of Peking University says. "With the exception of [20]fullerene, carbon structures made exclusively of pentagons are not known." This novel structure would resemble Cairo tiling, the team reports in the Proceedings of the National Academy of Sciences.





A photochemical approach to nitrogen fixation has been developed by US researchers, the discovery of a light-activated catalyst for converting nitrogen gas into ammonia could lead to low-cost agricultural fertilizers. "Scientists have been fascinated by the biological enzyme nitrogenase, which catalyzes the [nitrogen fixation] reaction in nature," explains team member Mercouri Kanatzidis of Northwestern University. "Now, we have created a successful mimic of nature's process." The team's catalyst is a porous chalcogel containing clusters of iron, molybdenum and sulfur (FeMoS), the three key chemical components at the heart of the nitrogenase enzyme. In their successful proof of principle experiments, the team concedes that the reaction rate is a thousand times lower than that observed with nitrogenase, but this is an important first step towards a synthetic approach to fixing nitrogen that avoids the high temperatures and pressures of conventional industrial processes.





The US Department of Homeland Security has awarded researchers at the University of Houston, Texas, a grant to boost the SenseNet project, which is being developed as a multi-tiered, multi-component aerosol detection sensor system for biological and chemical weapons. The three phase project with a total planned budget of $1.8 million over three years will design and implement faster, more autonomous, less expensive bio-threat detection systems.