Researchers at the University of Kentucky in Lexington have developed a wireless magnetoelastic medical sensor that provides easier, less-invasive diagnosis of stress-related gastroesophageal reflux disease. Developed with the support of the National Science Foundation and the National Institutes of Health, the sensor consists of a polymer-coated magnetoelastic film that changes shape according to the level of gastric acidity. Changes in the film's shape alter its resonant frequency, which is then measured using a receiver coil worn by the patient. Doctors may either insert the sensor into the esophagus using a thin, removable tube or have the patient swallow it. Powered by the interrogation signal, the sensor needs no batteries, and the materials cost just a few cents. In addition to its proposed medical uses, this technology may be applied to remotely measure a variety of parameters, including temperature, pressure, fluid-flow velocity, chemical analyte concentrations, and liquid viscosity.
Magnesium diboride (MgB2), an inexpensive and readily available chemical compound, may one day serve as a cost-effective superconducting material. That speculation comes in the wake of research performed at Aoyama-Gakuin University in Tokyo, Japan, where Jun Akimitsu and colleagues demonstrated that MgB2 superconducts at −234ºC. These findings, reported in the March 1 issue of Nature (see www.nature.com), suggest that MgB2 could overcome the two drawbacks that make existing superconductors impractical. The superconductors now available are based either on expensive materials or on compounds that require expensive cooling to low temperatures. Although the critical temperature (Tc) observed for MgB2 is relatively low when measured against that required by some other superconductors, it's considerably higher than what's been previously obtained with relatively simple, readily available compounds. Also, scientists believe it may be possible to raise the Tc of MgB2 dramatically merely by making some minor changes in the material's composition. That assessment is based on previous experience with other superconducting materials.
The wavelet group in the department of applied science at the Lawrence Livermore National Laboratory (LLNL) is studying signal processing using the wavelet transform. A relatively new mathematical tool, the wavelet transform has proven useful in the analysis of various types of signals, from 1D speech, biomedical, and seismic signals to 2D images. A key property is its ability to locate short-time, high-frequency features of a signal and at the same time resolve low-frequency behavior. This constant-Q type of analysis suits "real-world" phenomena very well. LLNL's research is targeting electrocardiogram compression, seismic signal feature extraction, and feature-based wavelet design.
Sharp's improved TFT LCD technology, ASV (advanced super view), has a 170° viewing angle horizontally and vertically, with response time confined to 25 ms or less. Competitive TFT LCD technologies offer response times between 80 and 150 ms. With such a short response time, ASV becomes a strong candidate for full-motion video. Other benefits include the total elimination of bright pixel defects that can be annoying artifacts when a TFT LCD is used in the black mode. Sharp plans to convert much of its TFT LCD production to ASV over the balance of this year. Products incorporating this technology will come along shortly.
Supported by a NASA grant, Nano-Sciences Corp. will develop a solar-blind, ultraviolet-sensitive photocathode based on III-IV aluminum gallium nitride (AlGaN). Coupling the photodiode with NanoSciences' micromachined silicon microchannel plate and miniature photomultiplier tube technologies should produce high-gain UV detectors that operate at low power and high speed over a large dynamic range. These detectors will have potential applications in astronomy, missile detection, atmospheric ozone monitoring, and other areas. To build the diode, NanoSciences will exploit molecular beam epitaxy to grow ordered thin-film AlGaN crystals on sapphire substrates, which will then be processed into photodiodes. In its pursuit of the desired UV frequency response, the company will investigate the detector's sensitivity to varying concentrations of aluminum and gallium and to changes in surface conditioning.