Breakthroughs, Briefly

Breathless in Beijing

Yi Cui may have made his name with cutting-edge battery advances—the kind of clean tech that could one day vastly reduce the smog smothering cities across the developing world. But about two years ago, repeated experiences with choking pollution in his native China compelled him to start looking for more immediate relief.

"It's personal for me. I wanted to do something about it," says Cui, an associate professor of materials science and engineering. "That's what engineers like to do, to solve problems."

The result, in Cui's words, could be a "game changer": a cheap, efficient and versatile filter made by spinning a polymer commonly found in surgical gloves into a finely threaded barrier that blocks tiny particulates yet remains open to light and air.

That last characteristic is critical, he says. Existing filters can already form a wall to pollutants, but typically at the expense of airflow and transparency, making them poor choices for use as window screens or face masks. His lab's prototypes, by contrast, make for more discriminating gatekeepers.

During a field test on a bad summer day in Beijing last July, the filter—using fibers a thousandth of the diameter of a human hair—trapped nearly 99 percent of soot, dust and other harmful particulates while retaining its transparency. It's a virtue particularly attractive for protecting buildings without having to turn to expensive, energy-sucking ventilation systems.

Photo: Stanford News Service

"It might be the first time in years that people in Beijing can open their window and let in a fresh breeze," he says.

The filters are strong but short-lived. In a week of heavy use, they can snatch up particles equal to 10 times their weight, but then they grow saturated and need replacing, Cui says. Their predicted low cost would make that fairly painless.

The filters might also have industrial applications, scrubbing car exhaust or power plant emissions, but such adaptations would require additional testing. The filter's ability to shield against viruses and bacteria is also being tested.

Cui has a patent pending and may start a company around the product. It's an area with no shortage of potential customers, but Cui, whose passion for renewable energy and environmental technology endures, certainly wouldn't mind if that changed.

That might sound like surreal humor, but when a 4-year-old girl arrived at the Children's Hospital of Michigan bleeding from the nose, no one was laughing.

Stanford otolaryngologist Ian Humphreys, then a resident at Detroit Medical Center, and his team stemmed the bleeding and sent her on her way. But the next morning she was back, her face pale and her nose bleeding briskly.

"This time, she had to be intubated," Humphreys said, to prevent the blood from blocking her airway.

The girl had Glanzmann thrombasthenia, a rare disorder that prevents blood from clotting. For a week and a half the doctors tried surgical tactics. None could stop the hemorrhage.

Typically, doctors would next resort to sealing off the nearby artery. But in this case, doing so could have left the child blind.

Running out of options, Humphreys dug into the medical literature. That's when he stumbled upon the idea of using salt pork. Evidently, infantrymen during World War I put pork on their wounds to control bleeding until they could find medical care.

Robert Jackler, chair of Stanford's otolaryngology, head and neck surgery department, said he's found references to its use against nosebleeds in materials dating back to the 1800s.

 "God knows who figured this out," he said. But it worked.

After a brief discussion, Humphreys and his team decided to try it before resorting to a more dangerous procedure. They crafted two porcine plugs and inserted them into the girl's nose. To everyone's relief, the bleeding stopped. When she returned a month later with another nosebleed, the doctors knew just what to do.

Even now, doctors aren't sure how the pork works. Wanting to spur further research on the subject, Humphreys's team published a paper about the episode.

For their ingenuity, the group received the 2014 Ig Nobel Prize in Medicine—a sort of anti-Nobel that aims to "celebrate the unusual [and] honor the imaginative."

While Humphreys said he was pleased to receive the honor, he hopes the work will lead to something bigger, "something that will have a positive impact for a wider swath of the population."

"For now, though," he said, "there's at least one little girl who's happy."