Editor's choice: Blood, ants to the rescue and solar cells
A round-up from the scientific and technical journals.
Is young blood the elixir of youth?
Maybe vampires were on to something. Last year, scientists at Harvard connected the blood circulation of an old and a young mouse for 30 days and found the hearts of the older mice were rejuvenated. Now in two new papers, the same Harvard group showed that a protein from young blood called GDF 11, that declines with age, has the same effect as young blood and can rejuvenate not only ageing hearts but also blood vessels, skeletal muscle and brain cells. The authors say GDF11 stimulates stem cells and Harvard has filed for patents. In a similar report, a team from the University of California, San Francisco, showed that blood from young mice triggered in old mice the growth of cells in the hippocampus, that part of the brain associated with memory. The two new papers can be found here and here.
Ants lead disaster victims to safety
Ant colonies have inspired a method for helping evacuees find the most direct way out of disaster zones. Whereas ants leave a trail of pheromones that their colony mates can follow to find the quickest path from A to B, people leave an electronic trail, via their smartphones. Researchers envisage using smartphones as networked, mobile sensors feeding information back to emergency centres. In simulated emergencies such as earthquakes and tsunamis, the researchers could track the movement of evacuees and rescue workers via their phones to create live maps that show the fastest route to safety. Even with telecoms infrastructure down, smartphones could network directly with each other to build an active map to circumvent fires or other blockages in escape routes. A report of the research can be found here.
Minerals turn up the voltage
Researchers making solar cells based on cheap, naturally occurring minerals called perovskites have made startling progress in the past three months, Science reports. Perovskites have been known to geologists since the 19th century, but only in 2009 were their photovoltaic properties discovered. At the time, the best perovskites showed a paltry 3.8% efficiency at turning sunlight into electricity. In February, cells with 16.8% efficiency were reported; this week three groups announced they had shattered that record, reaching almost 20%. That still trails the best solar material, gallium arsenide, which shows efficiencies above 40%, but perovskites are much easier and cheaper to make. The challenge researchers are now addressing is perovskites’ low tolerance to moisture.