I write brief summaries of peer-reviewed articles in the Journal of the American Chemical Society. They appear on the journal’s website: here.
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Biometric Bracelet Lets a Medical Device Recognize its Wearer
A device that measures someone’s unique response to a weak electric signal could let medical devices such as blood-pressure cuffs automatically identify the wearer and send measurements straight to his or her electronic medical record.
For now, nurses, patients, and doctors juggle the job of keeping patients’ identities straight. But computer scientist Cory Cornelius at Dartmouth College, in New Hampshire, has developed a wristwatch-like device that measures a person’s “bioimpedance” to identify him or her to medical monitoring devices.
Cornelius and colleagues presented a prototype sensor at the Usenix Advanced Computing System Association workshop in Bellevue, Washington, on Monday. Individual impedance varies because each person’s wrist, for example, is a unique jumble of bone, flesh, and blood vessels. Continue reading Biometric Bracelet Lets a Medical Device Recognize its Wearer
Point-of-care tests poised to alter course of HIV treatment
Testing for HIV does not simply end with the diagnosis that the virus is present in a patient; caregivers also need to track the disease’s progress to adjust ongoing treatment. Yet tests for monitoring HIV infection require sophisticated instruments, well-trained clinicians and expensive lab ware. All those are in short supply on HIV’s front line in places such as rural sub-Saharan Africa. “It’s a problem not just of cost,” explains hematologist Helen Lee of the University of Cambridge in the UK. “It’s a problem of having access.” In the last year, stripped-down standalone tests have appeared on the market, offering rural patients a cheaper, faster count of their CD4 immune cells. And in the coming months, a class of tests that measure viral load should enter routine point-of-care use, too, offering caregivers a choice of simple tools for measuring HIV infections.
Continue reading Point-of-care tests poised to alter course of HIV treatment
Lithium-Air Batteries Get a Recharge
Lithium, the lightest metal, when paired with oxygen from the atmosphere, makes for a tantalizing partnership in a lightweight battery. In theory, this “lithium-air battery” offers several times the energy per kilogram of today’s lithium-ion batteries. But so far, in laboratory tests the lithium gets distracted by dead-end chemical reactions that prevent the batteries from recharging. A one-shot battery is fine for a wristwatch, but not for a next-generation electric vehicle.
Last month, researchers in Rome and Seoul, South Korea, reported designing a lithium-air battery that did not have the recharging problem, achieving approximately 100 charge and discharge cycles with little capacity loss. And this week, a research team led by chemist Peter Bruce of the University of St. Andrews, in Scotland, reports in the journal Science a differently designed lithium-air battery that reached 100 cycles, losing only 5 percent of its capacity in the process. Bruce says that these recent results show that lithium-air batteries can sustain “a truly reversible reaction.” The group measured the mix of chemicals involved, showing that the lithium was really being recycled through a reversible substance, lithium peroxide (Li2O2), during each charge and discharge. Continue reading Lithium-Air Batteries Get a Recharge