weakening glass can make it stronger

Glass may be hard, but it's all too easy to break. Now scientists have discovered that they can make glass 200 times tougher than normal by making it "weaker" — using a laser to etch wavy micro-cracks. The discovery, described in Nature Communications, borrows secrets from mollusk shells. Seashells lined with iridescent mother-of-pearl are more than just pretty — they're a remarkable feat of microengineering, said co-author Francois Barthelat, a mechanical engineer at McGill University in Quebec, Canada. The secret is in the shell's nacre, the iridescent material lining the inner surface. It's made of 95 percent chalk — hexagonal plates of calcium carbonate in a crystalline form that interlock like Lego blocks. But the boundaries between these hard layers are filled with soft material that can deform. The team used this bio-inspired method on glass slides for microscopes, but it should be able to scale up for dinnerware, windowpanes and even car windshields.

How dogs know what you're feeling

When you hear a friend's voice, you picture her, even if you can't see her. And from the tone of her speech, you gauge if she's happy or sad. You can do this because your human brain has a "voice area." Now, scientists have discovered that dog brains, too, have voice areas. It helps explain how canines can be so attuned to their owners' feelings. "It's absolutely brilliant, groundbreaking research," says Pascal Belin, a neuroscientist at the University of Glasgow in Scotland, who was part of the team that identified voice areas in the human brain in 2000. Brain scans revealed that dog brains have voice areas and that they process voices in the same way that human brains do, the team reported online in Current Biology. And because these voice areas are found in similar locations in the brains of dogs and humans, the scientists suggest that they likely evolved at least 100 million years ago, when humans and dogs last shared a common ancestor, an insectivore. news services