The Malaysian Insider :: Features
The Malaysian Insider :: Features |
| Balkan folklore helps puts bite on bedbugs Posted: 14 Apr 2013 04:48 AM PDT  The pesky bedbug may have met its match. — AFP picPARIS, April 14 — It's been frozen, baked, suffocated and sprayed with toxins... and each time the bedbug bounces back, leaving tiny bite marks on legs or arms where it takes a blood meal. But thanks to an unusual combination of Balkan folklore and nanoscale science, the pesky critter may have met its match. In a journal of Britain's prestigious Royal Society, US entomologists on Tuesday reported progress in a quest to emulate anti-bedbug defence found in the hairs of leaves from the kidney-bean plant, known by its Latin name of Phaseolus vulgaris. In rural Bulgaria, Serbia and other parts of the Balkans, these leaves are scattered on the floor next to the bed, snagging the blood-sucking little parasites during their night-time forays. The following day, the bug-encrusted leaves are burned to exterminate the pests. Eager to find how the trick works, the scientists used high-speed video cameras and scanning electron microscopy to study lab bedbugs which had been coaxed into trotting across a bed of leaves. The investigators were surprised to find that the bedbugs were not trapped by some Velcro-like mechanism which entangled their legs or bodies. Instead, they discovered that the leaves are studded with extremely sharp points called trichomes that pierce the bedbugs' legs at critical locations. Impaled on several legs at the same time, the bugs are doomed. The next step was to copy the leaves, using them as a template for biomimickry. The goal is to make a bedbug barrier that is durable and can be used on any surface, not just the floor. In terms of size and geometry, the imitation prototype closely resembles the original. But it needs further work before it can be turned into a useful trap, for the bedbugs are only harpooned temporarily, the biologists admit. The reason may be that the natural trichome, about 60 billionths of a metre thick or 1/60,000th the width of a human hair, has a more flexible tip than the synthetic version. The point of the trichome skitters its way across the bug's cuticle surface before lodging in a leg crevice. "Nature is a hard act to follow, but the benefits could be enormous," said Michael Potter of the University of Kentucky, part of the team led by Catherine Loudon of the University of California at Irvine. "Imagine if every bedbug inadvertently brought into a dwelling was captured before it had a chance to bite and multiply." Bedbugs are an ancient scourge driven back by DDT and other then-legal pesticides in the post-World War II period. They have staged a spectacular comeback in recent years, infesting homes, hotels, schools, cinemas and hospitals. Fixes have ranged from low-tech barriers to carbon-dioxide sprayers to freeze them, and steamers and heaters to cook them. They inflict costs of at least a quarter of a billion dollars each year in the United States alone, according to the US National Pest Management Association. — AFP-Relaxnews |
| Even non-amputees experience ‘phantom limbs’, says study Posted: 14 Apr 2013 01:54 AM PDT  A study has shown that even non-amputees can experience 'phantom limbs'. — shutterstock.com picSTOCKHOLM, April 14 — Amputees often experience "phantom limbs", or the sensation that their missing limb is still present, but a Swedish study published Thursday showed that even non-amputees can experience the bizarre sensation. "Our results show that the sight of a physical hand is remarkably unimportant to the brain for creating the experience of one's physical self," said the lead author of the study, Arvid Guterstam of Sweden's prestigious Karolinska Institute. Phantom limbs can be distressing and painful for amputees, and drugs cannot help as the sensation is essentially a trick of the brain, which imagines the existence of a limb that is not there. Guterstam said his team hoped the results of their study would help lead to future research on amputees' phantom pain. The researchers conducted 11 different experiments creating a perceptual illusion so that volunteers with two arms and hands experienced having an invisible hand. In the experiments, participants sat at a table with their right arm hidden from their view behind a screen. A scientist then touched the participant's right hand with a paintbrush while imitating the exact movements with another paintbrush in mid-air within the participant's full view. "We discovered that most participants, within less than a minute, transfer the sensation of touch to the region of empty space where they see the paintbrush move, and experience an invisible hand in that position," Guterstam said. "Previous research has shown that non-bodily objects, such as a block of wood, cannot be experienced as one's own hand, so we were extremely surprised to find that the brain can accept an invisible hand as part of the body," he added. In another experiment, researchers made a stabbing motion with a knife toward the empty space "occupied" by the invisible hand and measured the participant's sweat response in their palms to the perceived threat. They found that the participants' stress responses were higher when they experienced the illusion, but absent when the illusion was broken. And in a third experiment, the volunteers were asked to close their eyes and point with their left hand to their right hand. After having experienced the illusion for a while, they pointed to the location of their invisible hand instead of the real hand. Researchers also measured brain activity, and found that the invisible hand illusion led to increased activity in the parts of the brain that are normally active when individuals see their real hand being touched. Seventy-four per cent of the 234 volunteers experienced a phantom limb during the experiments, Guterstam said. The results were published Thursday in the US Journal of Cognitive Neuroscience. — AFP-Relaxnews |
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