The Food and Drug Administration said Tuesday it approved a nerve-stimulating headband as the first medical device to prevent migraine headaches.

Agency officials said the device provides a new option for patients who cannot tolerate migraine medications.

With its exploding urban population burning ever more coal and wood, Africa could contribute as much as 55 percent of the world's particle pollutants by 2030, a study said Tuesday.

In 2005, the continent's global share of these atmospheric pollutants ranged from a five percent for sulphur dioxide and nitrogen oxide to 20 percent for organic carbon, according to the findings published in the journal Environmental Research Letters.

Nicotine patches fail to help pregnant women to stop smoking, according to a study published by the British Medical Journal (BMJ) Tuesday.

Researchers in France asked more than 400 women who smoked at least five cigarettes a day to try either a nicotine patch or a dummy patch called a placebo.

A natural compound hidden away in spinach has been shown to reduce food cravings between meals and could help prevent obesity, a Swedish scientist said on Monday.

Charlotte Erlanson-Albertsson, a professor of appetite regulation at Lund University, found the compound, known as thylakoid, while looking for ways to slow digestion and alleviate hunger pangs.

A sharp rise in US deaths from heroin and prescription abuse has created an "urgent public health crisis," Attorney General Eric Holder declared Monday, promising tougher enforcement and improved drug treatment.

In a statement on the Department of Justice website, Holder said deaths from overdosing on heroin had risen by 45 percent between 2006 and 2010.

A co-author of a Japanese study that promised a revolutionary way to create stem cells has called for the headline-grabbing research to be retracted over claims its data was faulty.

The findings, published by Japanese researcher Haruko Obokata and U.S.-based scientists in the January edition of British journal Nature, outlined a simple and low-tech approach in the quest to grow transplant tissue in the lab.

The handful of poultry dealers lingering at Chengbei Market have had little to do since Chinese authorities shut down their livelihoods after H7N9 bird flu began stalking the country again, killing scores of people this year.

They spend their days counting the losses to their business, gambling at cards and cleaning the cages which once held thousands of live birds, hoping the government will allow the trade to resume.

The Philippines plans to vaccinate seven million dogs within two years to end its status as one of the world's most rabies-prone nations, the health department said Monday.

By making at least 70 percent of the country's 10 million dogs resistant to the rabies virus, the department hopes to remove the disease as a cause of human death by 2016, four years earlier than originally targeted, health officials said.

An 11-year-old Cambodian boy has died of bird flu, a hospital official said Monday, the impoverished kingdom's third confirmed fatality -- all children -- from the illness this year.

The boy, who was from northern Kampong Chhnang province, died on Friday morning six hours after he was admitted to hospital, according to Denis Laurent, deputy director of Kantha Bopha Hospital in the capital.

Researchers in the United States say they have developed a prototype blood test that can tell with 90-percent accuracy whether a healthy person will develop Alzheimer's disease within three years.

The test looks for 10 signatures of fatty proteins called lipids, according to a study published on Sunday in the journal Nature Medicine.