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Spinal implant grows with the child
Technology
AMOS WINTER, a graduate student at the Massuchusetts Institute of Technology, has a new skill to add to his resumé. “Amos is now a licensed clam digger in the state of Massachusetts,” his supervisor, Anette Hosoi, says proudly. Razor clams retreat rapidly into the sand when threatened, making them elusive prey. The clams move with ease into muddy silt and gravelly sand, despite being able to exert a force only one-tenth that required for a person to push a clam shell into the sand. Winter dug up some clams to observe their uncanny burrowing ability, and then built a “roboclam” that is able to burrow into the sand by mimicking their action. “That’s what got the oil industry interested,” says Hosoi. If the clam’s technique can be replicated mechanically, it could
Spinal implant that’s ahead of the curve
CHILDREN suffering from the spinal condition scoliosis face the prospect of major surgery with lifelong complications. To try to avoid this, a new corrective implant is under development that “grows” with the child, harvesting the energy it needs from its host’s movements. 26 | NewScientist | 12 July 2008
Opponents say such drilling will threaten marine ecosystems and coastal fisheries while doing nothing to relieve the immediate energy crunch. But with US gasoline prices averaging over $4 per gallon, the oil industry’s enthusiasm for deep-water reserves is running high – though getting the oil out presents a major challenge. “As we move to deeper water everything becomes harder and vastly more expensive,” says Owen Oakley, a consultant with the research arm of Chevron. The high pressures and low temperatures at depths greater than 2500 metres will require more robust equipment and better communications. So the –Digging in– order-of-magnitude leap in digging efficiency demonstrated by the razor clam would be of The roboclam project is being sponsored by energy multinational great benefit to anchoring Chevron to the tune of $6.5 million systems, which are heavy and over the next five years. Chevron’s costly to deploy. The roboclam will be tested motivation grows more obvious in the field this autumn. Hosoi with every hike in oil prices. The admits the roboclam may not industry is hoping that sooner scale up to oil-rig proportions, but or later that the ban on offshore drilling will be lifted. Last month, even so it could be used to anchor and move smaller pieces of both US president George Bush equipment on the seabed. The and presidential candidate John industry is interested enough to McCain advocated lifting keep funding the work. “These are the ban, as did Florida governor not people worried about the end Charlie Crist, whose state has of oil,” she says. Ivan Semeniuk ● large offshore oil reserves. DAVID NUNUK/ALAMY
To put up an oil rig, follow that clam
prove ideal for anchoring offshore rigs in the soft seabed of the Gulf of Mexico and other oil-rich waters around the world. So how do the clams do it? A slowed-down video of a clam digging offers some clues. The clam first braces itself by opening its long shell, then extends its muscular foot forward. Then it partly closes its shell and backs off, which temporarily loosens the sediment in front. The clam then darts forward, gaining ground in the process.
Scoliosis affects as many as 1 in 50 adult women and 1 in 200 men, causing their spines to curve from side to side into unnatural “C” or “S” shapes. In severe cases, it is treated by grafting sections of bone or metallic fixators onto the spine to help straighten it. But this “spinal fusion” surgery usually cannot be done until a child is almost fully grown, by which time the symptoms are already advanced. The technique has other drawbacks, too: it restricts movement, and can cause surrounding muscles and ligaments to atrophy. “Vertebral fusion drastically [weakens] the strength of the skeleton,” says Jose Alvarez Canal, a mechanical engineer who has been working on the new
implant at NADAR Computerized Medical Systems in Langreo, Spain. Canal says that controllable machines are needed that progressively manipulate the spine over time. The new implant,
“A hydraulic piston applies a force between two points along the spine” developed in collaboration with spine experts from Spain and France, uses a hydraulic piston to apply a force between two points along the spine, gradually correcting its curvature. The device can be fitted to relatively young children, but as they grow and the piston moves, the force it exerts inevitably reduces. To correct
this, doctors need to top up the pressure on the piston. The NADAR device is designed to allow some free movement of the spine, some of which it harnesses to pump hydraulic fluid from a low-pressure reserve within the device into a highpressure reservoir. When adjustment is needed, the doctors use wireless telemetry to open a valve that releases fluid from the reservoir into the piston. The device is removed completely once the spine is straight, reducing the risk of complications. Tests on sheep have been very promising, Canal says, but it will be at least three years before it’s ready to be tried in humans (Mechatronics, DOI: 10.1016/ j.mechatronics.2008.04.006).
Duncan Graham-Rowe ● www.newscientist.com
AMOS WINTER, a graduate student at the Massuchusetts Institute of Technology, has a new skill to add to his resumé. “Amos is now a licensed clam digger in the state of Massachusetts,” his supervisor, Anette Hosoi, says proudly. Razor clams retreat rapidly into the sand when threatened, making them elusive prey. The clams move with ease into muddy silt and gravelly sand, despite being able to exert a force only one-tenth that required for a person to push a clam shell into the sand. Winter dug up some clams to observe their uncanny burrowing ability, and then built a “roboclam” that is able to burrow into the sand by mimicking their action. “That’s what got the oil industry interested,” says Hosoi. If the clam’s technique can be replicated mechanically, it could
Spinal implant that’s ahead of the curve
CHILDREN suffering from the spinal condition scoliosis face the prospect of major surgery with lifelong complications. To try to avoid this, a new corrective implant is under development that “grows” with the child, harvesting the energy it needs from its host’s movements. 26 | NewScientist | 12 July 2008
Opponents say such drilling will threaten marine ecosystems and coastal fisheries while doing nothing to relieve the immediate energy crunch. But with US gasoline prices averaging over $4 per gallon, the oil industry’s enthusiasm for deep-water reserves is running high – though getting the oil out presents a major challenge. “As we move to deeper water everything becomes harder and vastly more expensive,” says Owen Oakley, a consultant with the research arm of Chevron. The high pressures and low temperatures at depths greater than 2500 metres will require more robust equipment and better communications. So the –Digging in– order-of-magnitude leap in digging efficiency demonstrated by the razor clam would be of The roboclam project is being sponsored by energy multinational great benefit to anchoring Chevron to the tune of $6.5 million systems, which are heavy and over the next five years. Chevron’s costly to deploy. The roboclam will be tested motivation grows more obvious in the field this autumn. Hosoi with every hike in oil prices. The admits the roboclam may not industry is hoping that sooner scale up to oil-rig proportions, but or later that the ban on offshore drilling will be lifted. Last month, even so it could be used to anchor and move smaller pieces of both US president George Bush equipment on the seabed. The and presidential candidate John industry is interested enough to McCain advocated lifting keep funding the work. “These are the ban, as did Florida governor not people worried about the end Charlie Crist, whose state has of oil,” she says. Ivan Semeniuk ● large offshore oil reserves. DAVID NUNUK/ALAMY
To put up an oil rig, follow that clam
prove ideal for anchoring offshore rigs in the soft seabed of the Gulf of Mexico and other oil-rich waters around the world. So how do the clams do it? A slowed-down video of a clam digging offers some clues. The clam first braces itself by opening its long shell, then extends its muscular foot forward. Then it partly closes its shell and backs off, which temporarily loosens the sediment in front. The clam then darts forward, gaining ground in the process.
Scoliosis affects as many as 1 in 50 adult women and 1 in 200 men, causing their spines to curve from side to side into unnatural “C” or “S” shapes. In severe cases, it is treated by grafting sections of bone or metallic fixators onto the spine to help straighten it. But this “spinal fusion” surgery usually cannot be done until a child is almost fully grown, by which time the symptoms are already advanced. The technique has other drawbacks, too: it restricts movement, and can cause surrounding muscles and ligaments to atrophy. “Vertebral fusion drastically [weakens] the strength of the skeleton,” says Jose Alvarez Canal, a mechanical engineer who has been working on the new
implant at NADAR Computerized Medical Systems in Langreo, Spain. Canal says that controllable machines are needed that progressively manipulate the spine over time. The new implant,
“A hydraulic piston applies a force between two points along the spine” developed in collaboration with spine experts from Spain and France, uses a hydraulic piston to apply a force between two points along the spine, gradually correcting its curvature. The device can be fitted to relatively young children, but as they grow and the piston moves, the force it exerts inevitably reduces. To correct
this, doctors need to top up the pressure on the piston. The NADAR device is designed to allow some free movement of the spine, some of which it harnesses to pump hydraulic fluid from a low-pressure reserve within the device into a highpressure reservoir. When adjustment is needed, the doctors use wireless telemetry to open a valve that releases fluid from the reservoir into the piston. The device is removed completely once the spine is straight, reducing the risk of complications. Tests on sheep have been very promising, Canal says, but it will be at least three years before it’s ready to be tried in humans (Mechatronics, DOI: 10.1016/ j.mechatronics.2008.04.006).
Duncan Graham-Rowe ● www.newscientist.com