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The Alchemist kicks off the 2017 with antibiotic spider silk, nanochimneys for nanoelectronics, roadkill chemistry, and an explanation as to why warm water freezes faster than cold. We also hear how iodine could improve insulin and pick up the UK's New Year Honours.
Molecular diversity can be found in the most peculiar of environments. A team from the University of Oklahoma suggests that animals killed on the road might offer a surprising source of novel molecular structures. The source of the novelty lies in the obscure microorganisms that colonize the carcasses and produce a diverse range of natural products and metabolites any one of which might have any of the desirable range of properties in screening assays for physiologically active compounds. For instance, cyclic lipodepsipeptides produced by two bacteria isolated from the ear canal of a dead opossum showed activity in limiting biofilm formation by fungal cells associated with yeast infections.
Why does warm water freeze faster than cold water in the so-called Mpemba effect? For more than fifty years scientists have sought to explain or debunk the phenomenon, but it is only in considering that range of hydrogen bond types in water that exist at different temperatures have US chemists finally found a plausible explanation. They demonstrate that in warmer water, there is an abundance of one particular type of hydrogen bond whereas in colder there is more of another class. The hot water hydrogen bonds are more electrostatic in character as opposed to the more "covalent" colder hydrogen bonds. As such, the hydrogen bond network is stronger in hotter water - yet another anomaly of this endlessly anomalous material. Given the stronger network sudden cooling can lock in this more "frozen" structure without having to dissipate quite so much energy as with the more fluid cold water hydrogen bond network.
Swapping out a hydrogen atom for an iodine atom in the glucose-controlling hormone insulin makes it much faster acting, according to scientists in Switzerland. Fundamentally, the presence of the iodine in a specific position allows the natural, inactive hexamer form of insulin to break apart into six active monomers with greater efficiency and so make them available to the body for carrying out their job of modulating glucose levels in the blood more immediately. The insulin analog might offer a more effective way to control diabetes mellitus than unmodified insulin for patient although clinical trials to test safety and efficacy are yet to be undertaken.
Several scientists in the UK will receive awards for their efforts from in the "New Year Honours" bestowed by Her Majesty the Queen. Professor Shankar Balasubramanian, a chemist at the University of Cambridge, will become a knight of the realm, and thus a "Sir". John Pyle, also of Cambridge, will receive a CBE "Commander of the British Empire" while Professor Sir Alec Jeffreys who "invented" DNA fingerprinting will receive an additional award to become a "Companion of Honour."
Chemically functionalized spider silk could be woven into drug delivery, regenerative medicine and wound healing technology, according to UK scientists. The serendipitous discovery involves "click chemistry" in which functional groups can be clicked into place in soluble silk proteins before they form fibers. Tests on spider silk modified with the antibiotic levofloxacin show that the drug is released slowly from the silk extending activity for at least five days. Such a material might be useful in new types of wound dressings, for instance.
A cone-like graphene 'chimney' could carry heat away from a working nano-electronic circuit, according to research by scientists at Rice University. The heat is dissipated through quasiparticles known as phonons and could open up the possibility of keeping such futuristic circuitry cool. The Rice team's simulations of the structure at first suggested these wouldn't be able to carry phonons away and that the energy would simply be scattered reducing considerably the cooling effect. Structural tweaks revealed by the computer simulations now show that the nano chimneys could work well. Moreover, the structures can be tuned to almost any configuration for a range of applications.