Technology Bulletin

Patients breathe with pacemaker for larynx

A new implantable device helps patients with paralyzed vocal folds breathe on their own. The Implantable Pulse Generator (IPG), developed by doctors at Vanderbilt University Medical Center (Nashville, TN), allows a patient to speak and breathe normally through electrical stimulation. Surgeons insert an electrode next to the opening muscle of the larynx sandwiched between the cricoid cartilage and the muscle. The stimulation is done at the precise moment that the patient inhales, allowing the patient to take a breath," says David L. Zealear, Ph.D., associate professor of Otolaryngology and director of research in the department. The lead wire from the electrode is then brought subcutaneously through a tunnel to an incision below the clavicle. A pocket is made at that incision site and the stimulator is placed in that pocket. It can be re-programmed through the skin by using a microprocessor, Zealear says. "When the stimulus is discontinued, the muscles passively relax back to their midline position to allow normal voice production and airway protection." This is a real breakthrough for the 6,000 or so people stricken annually in the U.S. with bilateral laryngeal paralysis, he says. The condition is created when the two nerves that serve the larynx become paralyzed due to neck surgery. This is a life-threatening situation. Recently, the device was implanted for the first time ever in this country in a Missouri woman. "She has done really well," Zealear said. "We find that her ventilation with the IPG is working just as well as when she used her tracheotomy tube." And 65-year-old Helen Burns is pleased with the device. "It's wonderful to be able to breathe and to not have a trach. It's brought back my life and has helped me so much. I can do almost anything now." E-mail: matt.scanlan@mcmail.vanderbilt.edu   

Coconut oil isn't just for tanning anymore

A solution of coconut oil can power diesel engines while reducing emissions. So concluded researchers from Gunma University (Kiryu City, Japan) who experimented with different blends of gasoline and coconut oil. The group tested the mixtures on a 412-cc direct-injection engine to assess the possibility of using biomass fuels. The results showed that even pure coconut oil could power the engine without compromising brake specific energy consumption, though there was a mild reduction in output. In addition, the oil reduced the black smoke output by as much as 40%, and dropped emissions of nitrogen oxides by 20%. E-mail: s-jun@jimu.gunma-u.ac.jp or wakak@akagi.sb.gunma-u.ac.jp.  

Adding a fifth-layer to MEMS devices

By using a new five-level polysilicon surface micromachining process pioneered at the Department of Energy's Sandia National Laboratories (Albuquerque, NM) manufacturers will be able to produce more reliable microelectromechanical systems (MEMS) capable of doing increasingly complex tasks. "This five-level polysilicon surface micromachining technology has the potential of becoming the industry standard, replacing the more commonly used two- or three-level polysilicon surface micromachining approaches," says Steve Rodgers, Sandia engineer who together with colleague Jeff Sniegowski has spent the past several years prototyping designs and developing the innovative process. The five-level technology permits complex interacting mechanisms to be fabricated on moving platforms. To produce this fifth layer, Sniegowski and Rodgers had to develop a method for flattening the surface. As additional layers are added, more texture appears because the top acquires the characteristics of all the lower ones, including high and low spots. The result is the creation of protrusions, called "mechanical parasitics." These can interfere with operation. If the design doesn't take them into account, they could easily "collide with the teeth and prevent rotation of the gear," says Sniegowski. To eliminate this problem, a Sandia team led by process engineer Dale Hetherington, modified and patented a process commonly used in manufacturing integrated circuits, chemical mechanical polishing. Sandia will begin offering the five-level technology next spring to external customers for prototyping purposes, visit www.mdl.sandia.gov/micromachine. E-mail: Rodgers@sandia.gov. 

3D circuits will change the shape of things to come

Three-dimensional electronic circuits that can be molded into plastic objects will provide weight and space savings for many industries. Telecommunication manufacturers for example could capitalize on the potential weight reduction for the manufacture of mobile and cordless telephone handsets, and TV or video remote controllers. To produce them, a 3D framework of copper interconnection patterns is constructed and plated in a cheap metal foil. The framework is then placed in the mold cavity of an injection-molding machine where molten thermoplastic resin is forced into the cavity against the plated pattern. After cooling, researchers chemically remove the foil from the molding, revealing the 3D molded circuit. According to the October 1999 issue of Materials World, page 621, the materials used in this process provide sufficient resistance to high temperatures to allow operations such as mass soldering. The technology, developed by researchers at Interconnection and Electronics Chemicals in the UK, can be used to produce products that can be assembled with lower production costs than using traditional technologies and are 100% recyclable. The aerospace, automotive, and military industries are also interested in these circuits. E-mail: Materials_ World@materials.org.uk   

Hydrogen-rich liquid brings auto fuel cells one step closer

Researchers at Kogakuin University in Japan together with engineers at Sekisui Chemical say they developed an efficient liquid fuel for fuel cells that should drastically reduce the size of such systems. The new fuel has five to 10 times the hydrogen content of existing fuels, meaning a car can run for 400 km on 500 liters of the fuel. The liquid can also be stored in a plastic tank, which helps reduce the weight of a typical automobile. Fax: 310-375-0523.

Roll up your display and take it with you

New flexible flat panel displays may soon be available. Patterned, aligned carbon nanotubes, developed by researchers at Australia's CSIRO's Division of Molecular Science (Melbourne), are promising new electron field emitters for displays, offering high resolution and energy efficiency while using only a fraction of the power of liquid crystal displays. In addition, they can be rolled up and carried in your pocket. Carbon nanotubes are carbon hexagons arranged in a concentric manner with a diameter of one to tens of nanometers and the length of up to several micrometers. Having a conjugated all-carbon structure, carbon nanotubes can behave as a semiconductor or metal depending on their diameter and helicity of the arrangement of graphitic rings in the walls. The Australians' technique forms micropatterns of aligned carbon nanotubes by pyrolysis of organic-metal complexes containing both the metal catalyst and carbon source required for the nanotube growth. For manufacturing devices, micropatterns of aligned nanotubes can be produced either by patterned growth of the nanotubes on a partially masked/prepatterned surface or through a contact printing process, where substrate-free nanotube films are transferred to other substrates, such as polymer films, which otherwise would not be suitable for growth of the structures at high temperatures. Electrovac (Klosterneuburg, Austria) signed a $195,000 two-year collaborative research agreement with CSIRO to develop the new kind of screen for TV and computers. Visit: www.molsci.csiro.au.   

New building code helps construct earthquake-proof structures

A structural engineer from Purdue University (West Lafayette, IN) proposed an unorthodox approach for simplifying the design of earthquake-resistant buildings in Turkey. "Turkey now has a building code, especially devoted to earthquake-resistant design, that is highly sophisticated and quite scientifically respectable," says Mete Sozen, an expert in the design of earthquake-resistant structures and the Kettelhut Distinguished Professor of Structural Engineering at Purdue. The code, however, appears to be too good. "It's very difficult for run-of-the-mill engineers to deal with calculations and methodologies that require virtually a Ph.D. to use," says Sozen, who was a member of a field-investigation team sent to the site of a devastating temblor that struck his native Turkey on Aug. 17. Usually, an earthquake-resistant building is designed by first defining its architecture: calculating the weight and stiffness of construction materials, as well as the structure's "period of vibration," or how it moves in response to ground motion from quakes. Sozen's method revolves around a simple mathematical expression: one-half the sum of the cross-sectional areas of the building's columns, plus the sum of the areas of the horizontal cross sections of all the load-bearing walls, must be more than the total floor area divided by 1,000. The alternative method does have its limitations, he says. It should not be used for buildings higher than seven stories. However, it could be applied to most buildings and would improve safety in the long run because the present code is so complex that it is difficult to put into practice. E-mail: sozen@ecn.purdue.edu.   

Sensor detects pathogens in meat

A biosensor developed at the Georgia Tech Research Institute (GTRI) simultaneously identifies 12 species and calculates their concentrations of pathogens including E.coli and Salmonella. In less than two hours, the device can determine the safety of poultry and beef while on a processing plant floor. Currently, tests for bacterial pathogens in meat are not required by federal or state food regulators. A few companies who perform laboratory tests find these slow and expensive, requiring 48 to 72 hours before yielding results. The GTRI biosensor operates with three primary components: integrated optics, immunoassay techniques and surface chemistry test. The device indirectly detects pathogens by combining immunoassays with a chemical sensing scheme. Researchers are currently field testing the instrument, though commercialization is still some time away. E-mail: nile.hartman@gtri.gatech.edu.