from wastewater, researchers reported in March 2012. Their findings suggest that sewage treatment plants could one day be harnessed to produce energy rather than consuming it as they do today. The group from Pennsylvania State University in the US combined two types of energy-producing technologies in a bid to improve efficiency: a microbial fuel cell and a reverse electrodialysis system (Science, doi: 10.1126/science.1219330). In a microbial fuel cell, microbes consume plant or human waste and generate an electrical current. In reverse electrodialysis, solutions of saltwater and freshwater are pumped across specialised
A
compound similar to baking powder could be the key to producing electrical energy
membranes that allow only positively or negatively charged ions through; movement of these ions towards their respective electrodes generates an electrical current. By using ammonium bicarbonate as the fuel for reverse electrodialysis, rather than the usual seawater, the researchers were able to regenerate the salt solution continuously by harnessing small amounts of heat such as are produced by waste treatment. The group reported that their microbial reverse- electrodialysis cell (MRC) produced 0.94kWh of electricity/ kg of wastewater organic matter, against an energy consumption of 1.2kWh/kg on treatment with activated sludge.
US researchers reported in Ju Institute, slipped the genetic and injected it into nicotine- given the therapy continuou reached the brain. Their bra in untreated mice. The appro proved difficult to make as n
medication at the push of a remote-controlled button. In February, researchers in Denmark reported the results of the first clinical trial of such a wirelessly controlled microchip – to deliver an osteoporosis drug (Science Transl. Med., doi: 10.1126/scitranslmed.3003276). The team implanted the pacemaker-sized chip just below the waistlines of seven women with the disease, aged between 65 and 70, and reported that the implant delivered the drug teriparatide just as effectively as daily injections for 12 months.
Medicines on chip I
t could be the future for drug delivery: an implantable microchip that releases a patient’s
Biomarkers indicated improved bone formation and a reduced risk of bone fracture. The microchip could be an alternative to daily drug injections for severe osteoporosis sufferers and may boost quality of life and patient compliance. It could have much wider application beyond teriparatide, and may one day allow doctors to adjust a patient’s medication by computer or smartphone.
reported evidence that neonicotinoid insecticides, among the world’s most widely used pesticides, are harmful to bees. Both honeybee and bumble populations have declined rapidly in recent years, with multiple causes blamed for the fall in numbers. In the first study, researchers at the universities of Stirling and Lancaster exposed developing colonies of bumblebees to low levels of the insecticide imidacloprid, then placed them in an enclosed field site for six weeks (Science, doi: 10.1126/science.1215025). Compared with the control bee colonies that had not been exposed to imidacloprid, the treated colonies were on average 8 to 12% smaller than the control colonies at the end of the experiment – and produced about 85% fewer queens. In the second study, researchers in France
tagged free-ranging honeybees with tiny RFID microchips that were glued to each bee’s thorax. They then gave some of the bees a sub-lethal dose of the pesticide thiamethoxam
32 Chemistry&Industry • November 2012
Insecticide harms bees I
t had long been suspected, but in March 2012, two groups of researchers finally
and tracked the insects as they came and went from their hives (Science, doi: 10.1126/science.1215039). They reported that the treated bees were two to three times more likely to die while away from their nests and predicted by mathematical computation that honeybee populations exposed to the pesticide would drop to a point from which it would be difficult to recover – putting them at risk of colony collapse disorder. However, subsequent research
by the UK’s University of Exeter and the Food and Environment Agency, reported in the autumn, argues that the calculations in the latter study included an inappropriately low birth rate (Science, doi: 10.1126/science.1224930). When the experiment was repeated with a higher birth rate value, the researchers found the risk of colony collapse disorder disappeared.
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