Science  14 Dec 2012:
Vol. 338, Issue 6113, pp. 1403

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  1. Using Satellites to Detect Buried Nuclear Blasts

    Global satellite networks could become a powerful new tool for detecting clandestine underground nuclear explosions. Those explosions send up giant electromagnetic pulses that ripple through Earth's ionosphere, the portion of the upper atmosphere that is ionized by solar radiation. Although in theory, global satellite networks and radio telescopes should be able to spot the pulses, global monitoring efforts have instead relied on seismic, hydroacoustic, and radionuclide detection networks because earthquakes and major storms also cause ionospheric ripples. Last year, geodesist Dorota Grejner-Brzezinska and postdoc Jihye Park at Ohio State University, Columbus, and their colleagues pinpointed the 2009 nuclear blast in North Korea from these ripples. Last week at the fall meeting of the American Geophysical Union in San Francisco, they described algorithms for both GPS satellites and radio telescopes that enabled them to home in on two underground tests in the United States in 1992. However, even after the researchers work out the kinks, it's not clear that countries would add this technology to their monitoring efforts given that the Comprehensive Nuclear-Test-Ban Treaty has yet to be fully ratified.

  2. Porcupine Quills Could Inspire Better Medical Devices


    Tiny barbs coat the tips of porcupine quills.


    The secret behind a porcupine's painful quills are tiny barbs that help quills go in smoothly and not come out. Research into the function of these barbs could lead to improvements in bandages and hypodermic needles, says Jeffrey Karp, a bioengineer at Harvard Medical School in Boston. His team plunged barbed quills from North American porcupines, quills whose barbs they had sanded off, quills from an African porcupine that naturally lack barbs, and a quill-sized hypodermic needle into samples of pig skin, measuring how much force it took to pierce the flesh and then how much force was required to extricate the quill. To the researchers' surprise, barbed quills required only about half as much force as the barbless quills (whether naturally barbless or sanded clean) or the hypodermic needle did to breach the skin, they reported this week in the Proceedings of the National Academy of Sciences. Possible applications: wound dressings attached with tiny barbed needles instead of potentially allergenic chemical adhesives, and hollow versions of quill-inspired needles in drug-delivery patches.