The Alchemist Newsletter: Oct 26, 2012

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Graphite is well known as a lubricant material but researchers at the National Institute of Standards and Technology (NIST) have found that graphite can exhibit a negative coefficient of friction if a nanoscopic "pencil" tip of graphite is tested using atomic force microscopy and varying the amount of oxygen on the surface of a graphene sheet. Team member Zhao Deng found that the adhesive force between the graphene and the stylus became greater than the graphene layer's attraction to the graphite below, reducing the pressure on the stylus made it harder to drag the tip across the surface—a negative differential friction.

Slip Sliding Our Way: At the Nanoscale, Graphite Can Turn Friction Upside Down

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Carob is a well-known substitute for chocolate. Now, Nadhem Aissani of the University of Cagliari, Italy, and colleagues there and at the National Institute of Applied Sciences and Technology, in Tunisia, have shown that a methanolic extract of the leaves of the carob plant, Ceratonia siliqua, can inhibit the growth of Listeria monocytogenes in the laboratory. Listeria bacteria are a major cause of potentially lethal food poisoning in meat, fish and dairy products. As such, food researchers are keen to find safe and effective growth inhibitors that could be used as protecting agents to reduce the risk of listeria food poisoning in people eating such products.

Leaves of carob tree, source of chocolate substitute, fight virulent food-poisoning bacteria

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Everyday manufacturing often requires the bending and shaping of metallic components. Researchers at Aalto University in Finland and the University of Washington in the US have now demonstrated that the same approach might be possible on the nanoscale, allowing them to shear, bend and stamp out metallic for nanotechnology components. Writing in the journal Advanced Materials, the team reveals how it observed irregular folding at the nanoscale and realized that this behavior in thin metal films might be exploited to construct three-dimensional structures with design. The phenomenon is akin to the formation of 3D structures by Asian chefs who slice vegetable thinly and produce beautiful flower-like shapes when the slices are placed in water. The researchers have found that a focused ion beam can do the job of the water with their metal slices.

Manufacturing complex 3D metallic structures at nanoscale made possible

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An interdisciplinary team has developed a technique for "coloring in" the cell wall of bacteria to allow researchers to follow how bacteria grow more easily. The system could allow the effects of novel antibiotics to be monitored more easily. Indiana University chemist Michael VanNieuwenhze and biologist Yves Brun explain how multicolored probes target cell wall synthesis and allow the processes involved in bacterial replication to be filmed for diagnostic purposes as well as studies of antibiotics that might ultimately defeat bacterial resistance to conventional drugs. "Understanding the mechanisms controlling bacterial cell growth and shape is of tremendous importance in any area where we seek strategies for controlling bacteria, be it for the eradication of pathogens from the human body or the improvement of bacterial growth in bioremediation and industrial processes," VanNieuwenhze explains.

Filming bacterial life in multicolor as a new diagnostic and antibiotic discovery tool

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Avoiding the use of costly and rate platinum as the basic ingredient of fuel cells catalysts might be possible thanks to the development of an alternative based on cobalt and graphene developed by researchers at Brown University. Shouheng Sun and his colleagues have coated a graphene sheet with cobalt and cobalt-oxide nanoparticles, which they say can catalyze oxygen reduction almost as well as platinum but have the distinct advantage of being far more durable. The optimization of this new catalyst might displace platinum and lead to the more widespread adoption of this essentially nineteenth century technology by using 21st century materials.

Can cobalt-graphene catalyst beat platinum?

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The European Research Council (ERC) has awarded Achim Mueller of the University of Bielefeld, Germany, its biggest scientific award amounting to 1.2 million Euros (about $1.6m). Mueller's research focuses on the assembly of organometallic clusters and capsules with nanoscopic dimensions and has featured on numerous occasions in the popular press because of the visually stunning structures of these species as well as for their wide-ranging potential. Applications of his work might lie in catalysis, separations, carbon sequestration and sensors.

Bielefeld Chemist receives top EU science award

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