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This week The Alchemist learns about porous shape shifters, the return of the ozone eaters, X-rayed water at 100,000 degrees, optical fingerprinting, and a repurposing of erectile dysfunction drugs to prevent the post-operative spread of cancer. Finally, two sustainable awards for chemists.
Atmospheric levels of an ozone-destroying chemical,
trichlorofluoromethane, or CFC-11, are on the rise again despite it being banned under the Montreal Protocol in 2010. CFC-11 was widely used as a foaming agent, but phased out almost a decade ago because of its role in helping to form the ozone hole over Antarctica that begins to form each year in September. The US National Oceanic & Atmospheric Administration based at the University of Boulder Colorado says that emissions of this problematic gas are increasing which points to an unknown and unreported production source. Chlorofluorocarbons CFCs, were once widely used as refrigerants and as foaming agents. Alternatives were found and manufacture of this large class of materials was were phased out because of their damaging effects on the ozone layer. There still exist reservoirs of CFC-11 and other compounds in old refrigeration units and insulating construction materials. The NOAA is yet to identify the cause of this recent rise in atmospheric CFC-11 concentration.
An X-ray laser can heat water to 100,000 degrees Celsius in less than a tenth of a picosecond, creating a plasma of the familiar substance which could shed light on some of the bizarre properties of water. Of course, that amount of energy is not simply super-super-heating the water, rather the X-rays completely ionize the water leading to strong repulsive forces between the atoms. Bizarrely, although the water has been converted to the plasma state it retains the original density of water. The phenomenon could help guide X-ray studies of biological molecules in aqueous samples.
Supercharged biomacromolecules can maintain their reordered structures induced, for example, by a fingertip touch, according to work by scientists in China and The Netherlands. Stimuli-sensitive materials respond to physical forces with structural phase transitions and this also applies to biopolymer-surfactant mixtures, the team reports. The system uses a complex of a supercharged polypeptide with a cationic surfactant. This viscous liquid adopts birefringence patterns after being touched and so can reveal details such as fingerprints.
Mopping up cancer cells left behind after surgery might be possible by combining two very disparate medications - a common drug for erectile dysfunction and the flu vaccine. Rebecca Auer of The Ottawa Hospital and the University of Ottawa and her colleagues have demonstrated that a combination of either sildenafil (Viagra) or tadalafil (Cialis) with the inactivated influenza vaccine (Agriflu) can halt cancer metastasis after surgery, in mice. A trial in 24 human patients using Cialis and Agriflu is now under way. The mode of action seems to hinge on the fact that surgery leads to one type of immune cell that would normal kill metastatic cancer cells being blocked. The erectile dysfunction drugs block the blockers and the flu vaccine further stimulates the cells to kill the metastatic cancer cells.
Two projects that propose innovative solutions to sustainability problems are the winners of the third Elsevier Foundation Green and Sustainable Chemistry Challenge. The Challenge is run jointly by the Elsevier Foundation and the company's chemistry journals team. First prize winner is Prajwal Rabhindari, President of the Research Institute for Bioscience & Biotechnology (RIBB) in Nepal, will receive €50,000. The second prize winner is Alessio Adamiano, a researcher at the Italian National Research Council (CNR) Rabhindari has shown how guava leaves can be used to prevent food spoilage while Adamiano's work demonstrated how natural extracts of fish byproducts can be used as agricultureal fertilizer in Senegal.
There is huge potential in technology for shape-memory materials. They could be used in microelectromechanical systems (MEMS) and other devices as actuators, valves and artificial muscles as well as body implants for tissue engineering and bone regeneration in the wake of injury or disease. Now, shape-shifting, porous materials could be on the horizon through work carried out in Japan. X-ray diffraction reveals how these porous materials change through shape-memory effect. The phenomenon is well known in ceramics and metal alloys, but this is pioneering work in the area of porous crystalline solids.