30 Jun 2014

Editor's choice: Fishing spiders, solar cells, PET and pot

A round-up from the scientific and technical journals.

A Dolomedes facetus spider catches a tooth carp in a garden pond near Brisbane, Australia.Credit: Peter Liley

Fishing spiders take to the water

Once considered an oddity, fish-hunting spiders now appear to be widespread. Several species have become semi-aquatic hunters, swimming, diving or walking across water to capture pond insects. But occasionally they have also been spotted hauling ashore small fish. Trawling the scientific literature for examples of fishing spiders, researchers have now found that a diverse range of spider species across the planet have been photographed clutching their catch. The researchers suspect fish might be a rare, but nutritionally important, part of these spiders’ diets.

Bath salts clean up solar cells

A cheap, non-toxic salt could replace a problematic compound used in the manufacture of thin-film solar cells. So far, this has required washing with cadmium chloride, which is expensive and highly toxic. UK scientists have now shown that non-toxic, cheap magnesium chloride, which is used in bath salts, can substitute with no loss of performance. Thin-film cells currently cost a little less than traditional silicon cells, but are also less efficient. Any trick to cut their manufacturing costs could dramatically up their appeal. The author of the study said the simple fix took so long to find because “the cadmium chloride process wasn’t broken so no one wanted to fix it”.

Producing plastic from plants not petrol

The polymer PET (polyethylene terephthalate), used in everything from polyester to plastic drink bottles, requires a key ingredient that until now could only be made from crude oil. Chemists have discovered a way to produce PET entirely from renewable, plant-based materials. The key finding is a catalyst that can convert biomass into PET. Expect to find “green-labelled” slacks and plastic bottles coming to a store near you soon.

Research links schizophrenia and marijuana

Regular smokers of marijuana are twice as likely to suffer from schizophrenia as non-smokers. Some interpret this to mean that marijuana has caused it. Others argue that since the disorder is caused largely by the genes you inherit, the same set of genes that predispose a person to schizophrenia could also predispose them to using marijuana. A new study has found evidence supporting the latter view. Past studies identified schizophrenia’s genetic signature in people with the condition. Researchers have now shown that regular marijuana smokers are more likely than non-smokers to carry the same signature.