Rather than use scissors as per traditional technique, he operated with a flexible laser scalpel that a small manufacturer called OmniGuide had started selling earlier that year. It enabled Michaelides to avoid touching the inner ear’s delicate bones, which could cause more damage and more hearing loss. “It’s very accurate because you can place the tip of the instrument exactly where you want, change angles, and deliver precise amounts of cutting energy and coagulation throughout the middle ear,” says Michaelides. “The bottom line is that it is very precise and safe.”
Operating with flexible lasers isn’t new—surgeons have been using versions powered by carbon dioxide since the 1980s. Compared with a metal scalpel, carbon dioxide laser cuts are shallower, which means patients experience less postoperative pain, heal more quickly, and scar less. OmniGuide’s laser is one of the first to use optical fiber to guide its beam; previous versions used hollow metal tubes. The fiber permits even more precision, says OmniGuide founder Yoel Fink, making tricky procedures in challenging areas of the body safer.
OmniGuide, which has $80 million in venture capital investment, is one of a handful of companies that make flexible optical lasers. While competitors such as LuxarCare market mostly to small medical offices and veterinarians, OmniGuide, a 130-employee Cambridge (Mass.) manufacturer, has been gaining traction at hospitals across the U.S. So far, surgeons in about 500 hospitals are using OmniGuide's devices to perform about 1,400 surgeries a month—mostly for surgeries above the neck.
Now the company, which Fink expects will generate $21 million to $22 million in 2011 revenue, up from $18 million in 2010, is expanding its factory and developing a new line of laser fibers for procedures to treat disorders such as fibroids and other gynecological disorders.
Dr. Sharyn Lewin, a gynecologist specializing in oncology at Columbia University Medical Center, has used OmniGuide’s system to treat growths from papilloma virus and sees potential advantages for other procedures, such as endometriosis. “It’s a little more flexible for getting into smaller crevices,” says Lewin, comparing it with a traditional carbon dioxide laser. “It’s more precise, and there’s less tissue trauma. It’s easy to use and appears to be quite safe.”
Laser surgery isn’t without hazards. Accidents can happen if, for example, the laser beam touches a patient's sterile coverings or if oxygen and anesthetic gases build up while a surgeon is operating on the patient’s airway, says Michaelides. “But these instances are rare. It’s not a dangerous tool any more than a scalpel is, and surgeons are trained to use both to minimize risk.”
OmniGuide’s laser scalpel, which attaches to a small machine typically mounted on a rolling stand in an operating room, costs about $80,000, including two years of service. The laser, controlled by the doctor holding the fiber, acts as a scalpel to cut tissue close to the fiber’s tip. The fibers, which are designed to be used during a surgery and then thrown away, cost $500 to $1,500, depending on the procedure. "We try to be as [clinically] specific as we can," says Fink. "It's important because we want to do value pricing ... obviously the amount a patient or insurance agency will pay to restore hearing is less than to remove cancer from your brain."
Worldwide sales for surgical lasers will be $1.3 billion this year, up from $96 million in 2000, according to a 2010 report on medical laser systems by market research firm Global Industry Analysts.
Fink’s invention was sparked by a 1996 challenge by the Defense Advanced Research Projects Agency to scientists to design a highly reflective mirror. Then-graduate student Fink’s winning structure reflected objects from all angles, what he calls a “perfect mirror.” Fink’s mirror worked on differently shaped surfaces—flat, cubic, tubular. He reasoned that alternating rings of the chemical linings—an insulator and a semiconductor—would transmit the light through a hollow glass fiber. Because the laser beam could be controlled with the fiber’s tip, he envisioned, it would enable surgeons to reach difficult nooks and crannies more easily.
Fink, who holds a PhD in materials science from MIT, returned to academia this fall to run MIT’s Research Laboratory of Electronics, passing the reins at OmniGuide to Chief Executive Scott Flora, formerly a division president at surgical products maker Covidien. Fink’s lab is looking for other applications for his fibers, using funding from the U.S. Army to research material that images surroundings and garments that capture information from the body such as blood flow, temperature, and calories burned. And he envisions clothing woven of fibers that recharge cell phones, as well as chameleon-like apparel that changes color when the wearer leaves work. “Material will become a high-tech object, or the object of high-tech,” says Fink.
2011年12月26日星期一
2011年10月25日星期二
Digital isolation rivals optocouplers in terms of power, size and performance
For years, designers of industrial, medical and other isolated systems had limited options when implementing safety isolation: the only reasonable choice was the optocoupler. Today, digital isolators offer advantages in performance, size, cost, power efficiency and integration.
Understanding the nature and interdependence of the three key elements of a digital isolator is important in choosing the right digital isolator. These elements are: the insulation material: the structure: and the data transfer method.
Designers incorporate isolation either because of safety regulations or to reduce noise from such features as ground loops. Galvanic isolation ensures data transfer without an electrical connection or leakage path that might create a safety hazard. Yet isolation imposes a number of constraints, such as delays, power consumption, cost and size. A digital isolator's goal is, therefore, to meet safety requirements while minimising incurred penalties.
Optocouplers, a traditional isolation approach, incur the greatest number of penalties, consuming high levels of power and limiting data rates to less than 1Mbit/s. While more power efficient and higher speed optocouplers are available, these impose a higher cost penalty.
Digital isolators were introduced more than a decade ago to reduce penalties associated with optocouplers. These use cmos based circuitry and offer significant cost and power savings, while improving data rates significantly. They are defined by the elements noted above: insulating material determines inherent isolation capability and is selected to ensure compliance to safety standards; structure and data transfer method are chosen to overcome the cited penalties. All three elements must work together to balance design targets, but the one target that cannot be compromised and 'balanced' is the ability to meet safety regulations.
Digital isolators use foundry cmos processes and are limited to materials commonly used in foundries. Non standard materials complicate production, resulting in poor manufacturability and higher costs. Common insulating materials include polymers such as polyimide (PI), which can be spun on as a thin film, and silicon dioxide (SiO2). Both have well known insulating properties and have been used in standard semiconductor processing for years. Polymers have been the basis for many optocouplers, giving them an established history as a high voltage insulator.
Safety standards typically specify a one minute voltage withstand rating (typically 2.5kV rms to 5kV rms) and working voltage (typically 125V rms to 400V rms). Some standards also specify shorter duration, higher voltage (for example, 10kV peak for 50µs) as part of certification for reinforced insulation. Polymer/polyimide-based isolators yield the best isolation properties.
Polyimide based digital isolators are similar to optocouplers and exceed lifetime at typical working voltages. SiO2 based isolators, however, provide weaker protection against surges, preventing their use in medical and other applications.
The inherent stress of each film is also different. Polyimide has lower stress than SiO2 and can be increased in thickness as needed. The thickness of SiO2 and, therefore its isolation capability, is limited; stress beyond 15 µm may result in cracked wafers during processing or delamination over the life of the isolator. Polyimide based digital isolators, however, use isolation layers as thick as 26µm
Understanding the nature and interdependence of the three key elements of a digital isolator is important in choosing the right digital isolator. These elements are: the insulation material: the structure: and the data transfer method.
Designers incorporate isolation either because of safety regulations or to reduce noise from such features as ground loops. Galvanic isolation ensures data transfer without an electrical connection or leakage path that might create a safety hazard. Yet isolation imposes a number of constraints, such as delays, power consumption, cost and size. A digital isolator's goal is, therefore, to meet safety requirements while minimising incurred penalties.
Optocouplers, a traditional isolation approach, incur the greatest number of penalties, consuming high levels of power and limiting data rates to less than 1Mbit/s. While more power efficient and higher speed optocouplers are available, these impose a higher cost penalty.
Digital isolators were introduced more than a decade ago to reduce penalties associated with optocouplers. These use cmos based circuitry and offer significant cost and power savings, while improving data rates significantly. They are defined by the elements noted above: insulating material determines inherent isolation capability and is selected to ensure compliance to safety standards; structure and data transfer method are chosen to overcome the cited penalties. All three elements must work together to balance design targets, but the one target that cannot be compromised and 'balanced' is the ability to meet safety regulations.
Digital isolators use foundry cmos processes and are limited to materials commonly used in foundries. Non standard materials complicate production, resulting in poor manufacturability and higher costs. Common insulating materials include polymers such as polyimide (PI), which can be spun on as a thin film, and silicon dioxide (SiO2). Both have well known insulating properties and have been used in standard semiconductor processing for years. Polymers have been the basis for many optocouplers, giving them an established history as a high voltage insulator.
Safety standards typically specify a one minute voltage withstand rating (typically 2.5kV rms to 5kV rms) and working voltage (typically 125V rms to 400V rms). Some standards also specify shorter duration, higher voltage (for example, 10kV peak for 50µs) as part of certification for reinforced insulation. Polymer/polyimide-based isolators yield the best isolation properties.
Polyimide based digital isolators are similar to optocouplers and exceed lifetime at typical working voltages. SiO2 based isolators, however, provide weaker protection against surges, preventing their use in medical and other applications.
The inherent stress of each film is also different. Polyimide has lower stress than SiO2 and can be increased in thickness as needed. The thickness of SiO2 and, therefore its isolation capability, is limited; stress beyond 15 µm may result in cracked wafers during processing or delamination over the life of the isolator. Polyimide based digital isolators, however, use isolation layers as thick as 26µm
2011年9月22日星期四
Secret 3M material is at heart of new superfast chip
When it comes to computer chips, the world has always been flat. Their circuitry is etched onto a thin piece of silicon about the size of your thumbnail.
But that slice of silicon is getting full, and not much more microscopic circuitry can be squeezed onto it, analysts say.
So IBM and 3M have become partners in a new effort to make the chip world three-dimensional. They plan to stack circuitry in high-rise towers on top of computer chips in order to make computing modules that are 1,000 times more powerful than the chips used today in smartphones and other consumer electronics gadgets. This video helps explain the concept.
"You're talking about taking something that would normally sit under a desk being put into a package the size of a thumbnail," said Bernie Meyerson, IBM's vice president of innovation in Yorktown Heights, N.Y. The first thumbnail-sized computer modules are expected to be available in two to five years, he said.
3M, which admittedly is not a computer company, is nonetheless essential to the chip's design. Each layer of silicon circuitry in the "tower" would be separated from its neighbors above and below by layers of a 3M polymer that acts as an adhesive, an electrical insulator and a cooling material to carry away heat. The company declined to provide any details about the new material.
How is it possible to make thumbnail-sized computers? With ultra-thin computer layers. Only the bottom chip in the stack needs to be thick enough to be structurally strong, Meyerson said. The others can be much thinner. As a result, despite its "tower" description, an IBM-3M chip with 100 layers of circuitry stacked on top would not, to the unaided eye, be noticeably thicker than a normal computer chip, he said.
Smallness has its rewards. One of the keys to the IBM-3M package is that its compact size cuts the distance electronic signals must travel from one chip to the other, allowing the chips to run faster and use less electricity.
"So you're saving power and getting tremendous amounts of speed," Meyerson said.
"The fascinating aspect of these chips is that you can put phenomenal capability in a very tiny area," Meyerson said. "But logic chips generate large amounts of heat, and we must get that heat to propagate to the top and sides of the chip to get rid of it. And heat just hates to do that."
Enter the 3M polymer layer, which allows heat to flow through it to get out of the chip. Without that layer, the chip's self-generated heat would cause it to expand and break apart, Meyerson said.
"Without getting into any detail about what's in the 3M polymer, I can tell you that it works because of the linkages between atoms," Meyerson said. "If you can change the way the atoms bond to one another, you can increase or decrease a property of the polymer. This is the miracle of what they do at 3M. It's really magic unless you're a Ph.D in chemistry."
The technology will be watched closely in the competitive semiconductor industry.
"If the 3M-IBM film is truly an electrical insulator and a heat conductor, it is revolutionary, since such materials don't exist in nature and have to be engineered," said Mali Venkatesan, a semiconductor analyst at research firm IDC in San Mateo, Calif. "We have to wait and see the results."
But that slice of silicon is getting full, and not much more microscopic circuitry can be squeezed onto it, analysts say.
So IBM and 3M have become partners in a new effort to make the chip world three-dimensional. They plan to stack circuitry in high-rise towers on top of computer chips in order to make computing modules that are 1,000 times more powerful than the chips used today in smartphones and other consumer electronics gadgets. This video helps explain the concept.
"You're talking about taking something that would normally sit under a desk being put into a package the size of a thumbnail," said Bernie Meyerson, IBM's vice president of innovation in Yorktown Heights, N.Y. The first thumbnail-sized computer modules are expected to be available in two to five years, he said.
3M, which admittedly is not a computer company, is nonetheless essential to the chip's design. Each layer of silicon circuitry in the "tower" would be separated from its neighbors above and below by layers of a 3M polymer that acts as an adhesive, an electrical insulator and a cooling material to carry away heat. The company declined to provide any details about the new material.
How is it possible to make thumbnail-sized computers? With ultra-thin computer layers. Only the bottom chip in the stack needs to be thick enough to be structurally strong, Meyerson said. The others can be much thinner. As a result, despite its "tower" description, an IBM-3M chip with 100 layers of circuitry stacked on top would not, to the unaided eye, be noticeably thicker than a normal computer chip, he said.
Smallness has its rewards. One of the keys to the IBM-3M package is that its compact size cuts the distance electronic signals must travel from one chip to the other, allowing the chips to run faster and use less electricity.
"So you're saving power and getting tremendous amounts of speed," Meyerson said.
"The fascinating aspect of these chips is that you can put phenomenal capability in a very tiny area," Meyerson said. "But logic chips generate large amounts of heat, and we must get that heat to propagate to the top and sides of the chip to get rid of it. And heat just hates to do that."
Enter the 3M polymer layer, which allows heat to flow through it to get out of the chip. Without that layer, the chip's self-generated heat would cause it to expand and break apart, Meyerson said.
"Without getting into any detail about what's in the 3M polymer, I can tell you that it works because of the linkages between atoms," Meyerson said. "If you can change the way the atoms bond to one another, you can increase or decrease a property of the polymer. This is the miracle of what they do at 3M. It's really magic unless you're a Ph.D in chemistry."
The technology will be watched closely in the competitive semiconductor industry.
"If the 3M-IBM film is truly an electrical insulator and a heat conductor, it is revolutionary, since such materials don't exist in nature and have to be engineered," said Mali Venkatesan, a semiconductor analyst at research firm IDC in San Mateo, Calif. "We have to wait and see the results."
2011年6月12日星期日
Govt swings into action in flamingos death case
BHAVNAGAR: The officials who had ignored complaints by nature lovers about hundreds of flamingos being electrocuted daily as they flew into high tension wires swung into action after TOI reported the incident.
Officials of Gujarat Energy Transmission Corporation Limited (GETCO) visited the 300-hectare marsh on the outskirts of Bhavnagar on Sunday and camped there throughout the day. ''We have visited the site and carried out video recordings of the incident to ascertain the cause of
the birds' death. We are also getting a post-mortem done to ascertain whether they died of electrocution or some other cause,'' said
N P Maheshwari, superintending engineer, Amreli circle, GETCO.
''It seems that there may be reasons other than electrocution as our sub-stations have not reported as to when the birds hit the wires,'' Maheshwari said. However, members of the Dharmakumarsinhji Nature Conservation Society, which had reported the incident, said the bodies of the flamingoes were found mostly below the wires. They also said the flamingos could be seen falling after hitting the wires.
''If the wires are the reason behind the deaths of the birds, we will find a solution immediately,'' Maheswari said.
The solutions involve coating the wires with an insulator, diverting the line or taking it underground.
According to locals, the situation is made worse by stray dogs who attack these birds, causing the flock to take off in panic and hit the 66KV high tension cables.
''To minimise the casualty, the forest department should at least catch the stray dogs,'' said Harshil Shah, a member of Black Buck Nature Club, Bhavnagar. ''We tried to carry out
a rescue operation but
are unable to save their lives as they are injured badly,'' he said.
Officials of Gujarat Energy Transmission Corporation Limited (GETCO) visited the 300-hectare marsh on the outskirts of Bhavnagar on Sunday and camped there throughout the day. ''We have visited the site and carried out video recordings of the incident to ascertain the cause of
the birds' death. We are also getting a post-mortem done to ascertain whether they died of electrocution or some other cause,'' said
N P Maheshwari, superintending engineer, Amreli circle, GETCO.
''It seems that there may be reasons other than electrocution as our sub-stations have not reported as to when the birds hit the wires,'' Maheshwari said. However, members of the Dharmakumarsinhji Nature Conservation Society, which had reported the incident, said the bodies of the flamingoes were found mostly below the wires. They also said the flamingos could be seen falling after hitting the wires.
''If the wires are the reason behind the deaths of the birds, we will find a solution immediately,'' Maheswari said.
The solutions involve coating the wires with an insulator, diverting the line or taking it underground.
According to locals, the situation is made worse by stray dogs who attack these birds, causing the flock to take off in panic and hit the 66KV high tension cables.
''To minimise the casualty, the forest department should at least catch the stray dogs,'' said Harshil Shah, a member of Black Buck Nature Club, Bhavnagar. ''We tried to carry out
a rescue operation but
are unable to save their lives as they are injured badly,'' he said.
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