What the scientists are saying…

Theia’s crash kindled life on Earth It’s long been known that when Earth was formed, it did not have the ingredients necessary for life. So where did these “volatiles” – elements such as carbon, nitrogen, sulphur and hydrogen that are naturally depleted on rocky planets in our solar system – come from? One theory is that they were delivered by comets and meteorites long after the Earth formed (the so-called late veneer theory). But new research suggests that, in fact, they arrived far earlier, some 4.4 billion years ago, when a Mars-sized planet named Theia is believed to have slammed into the proto-earth. This violent impact threw up vast amounts of debris, some of which coalesced to form the Moon, while other bits of Theia were incorporated into the young Earth – and may have provided it with the building blocks of life, according to a team at Rice University in Texas. Using the results of various lab-based experiments involving a hypothesised Earth core, the researchers ran more than a billion simulations to work out how Earth could have acquired its volatile chemicals; this pointed to a collision with a planet with a sulphur-rich core. Given this planet’s likely size, and the likely time of the impact, they believe the planet must have been Theia. “We connected the dots,” said co-author Rajdeep Dasgupta.

Generating power from thin air The electromagnetic waves in the air all around us could be “harvested” and used to power wireless devices, scientists have claimed. Writing in Nature, researchers from the Massachusetts Institute of Technology describe creating a flexible, super-thin material encasing a semiconductor layer only three atoms thick, which can convert Wi-fi signals and other radio-frequency signals into electrical currents. In lab tests, the device reaped 30 to 50 microwatts from Wi-fi signals of about 100 microwatts. “It doesn’t sound like much compared with the 60 watts that a computer needs, but you can still do a lot with it,” said lead researcher Professor Tomás Palacios. Such a conductor could potentially power many devices, from pacemakers and hearing aids to environmental sensors – making them both lighter and more environmentally friendly.

Ibuprofen’s role in cancer survival Many cancer patients would boost their chances of survival by regularly taking ibuprofen or aspirin, new research suggests. The University of California study focused on a genetic mutation known as PIK3CA, which is present in about a third of head and neck cancer tumours (and is also often present in breast, bowel and endometrial cancers). The team monitored five-year survival rates among 266 head and neck cancer patients whose tumours had been removed. Among patients whose tumours had the mutation, and who took two or more weekly doses of non-steroidal anti-inflammatory drugs (NSAIDS), survival rates were 78%. For everyone else, they were 25%. The researchers believe NSAIDS block the production of an inflammatory molecule called prostaglandin E2, which boosts the growth of tumours with the mutation. “Our results suggest that the use of NSAIDS could significantly improve outcomes for not only head and neck cancer patients, but also patients with other cancers that contained the PIK3CA mutation,” said lead researcher Professor Jennifer Grandis.

Social media and depression The idea that spending time on social media fuels teenage depression may be mistaken: the latest research suggests that depression is what drives many teenagers to social media. Most studies looking at depression and social media have examined the relationship at a single point in time – making it hard to establish which factor is causal. Researchers at Brock University, Canada, adopted a longitudinal approach, surveying teenagers and university undergraduates over several years. This revealed that the amount of time a teenager spent on social media didn’t predict how likely he or she was to develop depression. However, the researchers did observe that girls with depressive symptoms at the outset were more likely, over time, to be heavy users of social media. “Adolescent girls who are feeling down may turn to social media to try and make themselves feel better,” commented lead author Taylor Heffer.