A stroke therapy using stem cells extracted from patients' bone marrow has shown promising results in the first trial of its kind in humans.

Five patients received the treatment in a pilot study conducted by doctors at Imperial College Healthcare NHS Trust and scientists at Imperial College London.

The therapy was found to be safe, and all the patients showed improvements in clinical measures of disability.

The findings are published in the journal Stem Cells Translational Medicine. It is the first UK human trial of a stem cell treatment for acute stroke to be published.

Researchers working on biomimicry have produced the first structural color change in an animal by influencing evolution: They've changed the color of the butterfly Bicyclus anynana from brown to violet - and needed only six generations of selection to do it.

Little is known about how structural colors in nature evolved, although researchers have studied such mechanisms extensively in recent years. Most attempts at biomimicry involve finding a desirable outcome in nature and simply trying to copy it in the laboratory.

The discovery published in Proceedings of the National Academy of Sciences may have implications for physicists and engineers trying to use evolutionary principles in the design of new materials and devices.

Physicists have identified a mechanism that may help explain Zipf's law – a unique pattern of behavior found in disparate systems, including complex biological ones. Their mathematical models demonstrate how Zipf's law naturally arises when a sufficient number of units react to a hidden variable in a system.

As the complex story of climate change unfolds, many of the forecasts are grim, but there are exceptions - the lowest-oxygen environments in the ocean would get now get worse, they may improve if climate change weakens the trade winds. Areas of extreme low-oxygen waters could shrink.

Warmer water contains less gas, so climate change is expected to reduce oxygen levels worldwide. Observations show this is already taking place in many places. Declines during the past 20 years in the tropical low-oxygen zones, the lowest-oxygen waters on the planet, had led to a 2008 study proposing that these zones would also get worse over time.

Oxazepam, a drug that is commonly used to treat insomnia and anxiety in humans, has been shown to reduce mortality rates in fish when it gets into natural water supplies. 

For their study, researchers retrieved two-year-old Eurasian perch from a lake in Sweden and randomly exposed them to high and low concentrations of Oxazepam, a benzodiazepine which is commonly used to treat anxiety and insomnia in humans and regularly contaminates surface waters via treated wastewater effluent. The researchers have previously found that the drug can increase the activity and boldness of Eurasian perch. 

Researchers have developed a powerful new tool to identify genetic changes in disease-causing bacteria that are responsible for antibiotic resistance. The team looked at the genome of Streptococcus pneumoniae, a bacterial species that causes 1.6 million deaths worldwide each year. In the most detailed research of its kind, scientists used a genome-wide association study (GWAS) to locate single-letter changes in the DNA code of the bacterium, which enable it to evade antibiotic treatment.

While GWAS has been used for a decade to identify gene function in humans, it was thought to be difficult to use the technique on bacterial DNA.