Science Briefs: Time-honored stethoscope may be replaced by smartphone app

One of the study authors shows how HeartBuds works with smartphone, during the American Heart Association scientific sessions in Orlando, Fla.
One of the study authors shows how HeartBuds works with smartphone, during the American Heart Association scientific sessions in Orlando, Fla. American Heart Association

Smartphone app challenges stethoscope

The stethoscope we’ve become accustomed to seeing draped around the necks of doctors and healthcare providers may someday be replaced by smartphones and a new portable device, called HeartBuds, that is slightly larger than a 25-cent piece.

“They not only detect sounds inside the body just as well – or better – than traditional stethoscopes, but they are more sanitary," said David Bello, MD, department chief of cardiology at Florida’s Orlando Health, and developer of HeartBuds. "And because they incorporate smartphone technology, we can now record, store and share those sounds as well.”

The stethoscope was invented in 1816 and has essentially been unchanged since. But with HeartBuds, doctors use a small, portable plastic listening device shaped much like the head of a traditional stethoscope. But instead of being attached to a Y-shaped tube that feeds into the doctor’s ears, this device is plugged into a smartphone.

When the app is activated, sounds from the hand-held device can be played through the smartphone speaker and images appear on the screen showing rhythmic blips that correspond with each sound. With this technology health care providers can control the volume, listen to and discuss sounds with patients in real time, and record data for future reference.

Technique makes titanium even stronger

Researchers at N.C. State and the Chinese Academy of Sciences have developed a technique to make titanium stronger without sacrificing any of the metal’s ductility – flexibility – a combination that no one has achieved before. The researchers believe the technique could also be used for other metals, and the advance has potential applications for creating more energy-efficient vehicles.

“Historically, a material is either strong or ductile, but almost never both at the same time,” said Yuntian Zhu, a professor of materials science and engineering at N.C. State and an author of a paper describing the work. “We’ve managed to get the best of both worlds. This will allow us to create strong materials for use in making lighter vehicles, but that are sufficiently ductile to prevent the material from suffering catastrophic failure under strain.”

The key idea is grain size – the size of the crystals in the metal. Metals with a small grain size are stronger: They can withstand more force before they start to deform. But metals with a small grain size are also less ductile: They can withstand less strain before breaking. Materials that aren’t ductile won’t bend or stretch much – they just snap. Conversely, metals with a large grain size are more ductile, but have lower strength.

The paper was published in the Proceedings of the National Academy of Sciences.

A better way to remove salt from salt water

University of Illinois engineers have found an energy-efficient material for removing salt from seawater.

The material, a nanometer-thick sheet of molybdenum disulfide (MoS2) riddled with tiny holes called nanopores, is specially designed to let high volumes of water through but keep salt and other contaminates out.

Most available desalination technologies rely on a process called reverse osmosis to push seawater through a thin plastic membrane to make fresh water. The membrane has holes in it small enough to not let salt or dirt through, but large enough to let water through. They are very good at filtering out salt, but yield only a trickle of fresh water.

One way to dramatically increase the water flow is to make the membrane thinner, and researchers have been looking at nanometer-thin membranes such as graphene. However, graphene presents its own challenges.

In a study published in Nature Communications, the Illinois team found that MoS2 showed the greatest efficiency, filtering through up to 70 percent more water than graphene membranes. A single-layer sheet of MoS2 outperformed its competitors thanks to a combination of thinness, pore geometry and chemical properties.