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The Alchemist gets down with the geckos this week, or not, as the case may be. Meanwhile learns how to make multi-layered graphene flakes with ultrasound and finds caffeine, cocaine and more in ultratrace quantities in the water supply. In ancient news, we hear that Libyans have been dairy farming for at least 7000 years. The newest bond on the block is the halogen bond. Finally, PhD recognition in the form of this year's Reaxys PhD Prize.

Researchers have taken another step forward in understanding how gecko's feet are so simultaneously sticky and non-sticky. These lizards famously cling to almost any surface with little effort it seems whether horizontal, vertical or upside down, and yet the adhesive properties of their hairy feet are not fully understood. After all, if the foot pads are so sticky, how does the creature unstick its feet to move? Shihao Hu at the University of Akron and colleagues have demonstrated how the toe-peeling action of the gecko's stride allows dirt particles that adhere to the setae, the sticky hairs, to be dislodged with each step, refreshing the hairy surface ready to stick to the next point on the rock face, tree, or ceiling. Researchers are keen to understand such details in their quest to find novel adhesive materials that work in a wide range of conditions for countless engineering applications.

The most well known approach to making the carbon allotrope graphene, which is akin to single graphite sheets, was to peel pencil "lead" (graphite) from a glass surface using sticky tape. Making multilayer graphene flakes however was a little harder. Now, researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw, and the Interdisciplinary Research Institute in Lille, France, have developed a low cost method for manufacturing multilayered graphene sheets. The team begins with graphene oxide and mixed it with tetrathiafulvalene in an ultrasonic cleaner to remove oxygen atoms from the graphene flakes through the formation of non-covalent pi-pi stacking interactions. Other than the sonicator, the approach needs no specialist equipment, nor sticky tape.

A team based in Spain has tested drinking water samples from Europe, Japan and South America for various legal and illicit drugs. Their analysis revealed the presence of caffeine and nicotine as well as cotinine, cocaine and its metabolite benzoylecgonine, methadone and its metabolite EDDP. However, while caffeine was present at relatively high levels, the researchers describe the presence of cocaine and illicit drugs as at only ultratrace levels on the boundary of detectability. The presence of pharmacologically active agents in the water supply has been an ongoing environmental concern, with worries about the presence of estrogenic compounds and toxic chemicals. The work by the team provides a new baseline for a wide range of compounds for future studies and epidemiological work.

Humans were dairy farming in Saharan Africa at least 7000 years ago, according to a new analysis of pottery from an archeological site in Libya. Around 10,000 years ago the people of the Sahara region enjoyed a wetter and more verdant environment than we see today and lived the hunter-gatherer lifestyle. However, evidence of cattle bones in cave deposits and river camps suggests that these people began herding cattle between 5000 and 7000 years ago. Now, a team at the University of Bristol, UK, working with colleagues at La Sapienza, University of Rome, Italy, have used lipid biomarkers and stable carbon isotope analysis to investigate organic residues, preserved fatty acids, in pottery from the Takarkori rock shelter. The work confirms the use of cattle for milk 7000 years ago. The work also provides new clues to the emergence of the evolution of a lactase persistence gene which arose at this time in prehistoric people.

A new type of bond not dissimilar to the hydrogen bond but involving a halogen atom has been uncovered by chemists in Switzerland. The so-called "halogen bond" could have implications for the behavior of biomolecules in fatty environments. Stefan Matile points out that the halogen bond operated in hydrophobic conditions whereas the hydrogen bond works only in aqueous systems. Earlier research has hinted at a halogen bond in the context of the iodine atom and thyroid function. The team has now created a non-covalent halogen bond between a carbon and an iodine atom and demonstrated that it can interact with anions and transport them across a model cell membrane in the form of a phospholipid bilayer.

This year's winners of the Reaxys PhD prize have been announced. Candidates submitted a representative peer-reviewed paper, their PhD supervisor's letter of recommendation and their CV. Submissions were reviewed by the Reaxys board of more than 80 leading chemists from around the world and judged on originality, innovation, importance to the field, applicability, rigor of approach and publication quality. The three regional coordinators from Europe, USA and Asia made the final selections to Gregory Hamilton for asymmetric transition metal catalysis, Debashis Mandal for synthesis of dragmacidin D, and Craig Stivala for traceless auxiliaries.