The use of ultrasound phased array, high-intensity focusing systems for ablation of tissue (surgery) allows electronic control of focal size and shape, as well as position, thus eliminating the necessity of a cumbersome mechanical scanning apparatus. While phased arrays have been employed for medical diagnostic and therapeutic applications (hyperthermia), they often require a prohibitively large number of elements. This study will determine if sparsely filled arrays, with the individual elements randomly located on the array surface, will facilitate the use of larger elements and spacing than used currently, reducing the number of elements and amplifiers required.

This study involves the continued development of a new generation of commercial ultrasound applicators and associated hardware/software capable of improved heating uniformity and depth control within the body, with specific application to thermal therapy for breast cancer and chest wall recurrence. Specifically, applicators will be constructed and tested that will offer (1) higher frequency operation to limit penetration depth where indicated, (2) simultaneous dual frequency operation so the frequency can be independently selected for the different elements in the applicator array, and (3) an improved means for coupling these new applicators for breast and chest wall treatments.

This pilot research study is aimed at the development of a dynamic dermofluorometer for the rapid and continuous recording of tissue fluorescence. Such an instrument should increase the diagnostic information provided by fluorescence tissue measurements when incorporated into a pharmacokinetic model of dye distribution. Thus, tissue fluorescence changes in response to exercise, localized heating, or drug therapy could be used to obtain dynamic information on the physiological state of tissue.

The general goal of this project is the development of improved teaching methods and materials for preparing science and mathematics teachers. The specific aim is to develop models and examples that incorporate new science and engineering instructional materials into teacher preparation courses for elementary and secondary education teachers. This effort is a collaboration between the College of Education and the College of Engineering at UIUC. Current advances in science, engineering, and bioengineering research in the College of Engineering are being transferred into teacher preparation courses and internships offered by the College of Education.

The objective of this project is a systematic study of the ultrasonic propagation properties of muscle using the scanning laser acoustic microscope. The study explores the acoustic heterogeneity of individual muscles and its relationship to the muscle's physical properties. The physical processes are known to affect muscle quality and the acoustic assessment is aimed at a noninvasive means to evaluate muscle quality.

The objective of the research program is to develop the basic acoustic propagation and backscattering database to evaluate the acoustic imaging tradeoffs for detecting and characterizing buried artifacts in ground soil.

The specific research aims are to measure the ultrasonic energy delivered to the human ovary, early embryo, and mid-trimester fetus using currently available diagnostic imaging equipment. Specially designed hydrophones will be placed as close as possible to the ovaries in normal volunteers. Exposure to the embryo will be determined by placing the hydrophones as close as possible to the embryo in utero. Once the dosimetry in these clinical situations has been established, then meaningful data regarding the effect of diagnostic ultrasound in human pregnancy can be ob tained and ``safe'' levels of ultrasonic energy established for patients of varying size and gestation.

The objective of this research is to evaluate theoretical tissue temperature increases due to focused diagnostic ultrasound fields under various realistic tissue models. The approach is to apply the point-source, harmonic, spherical solution of the linear acoustic wave equation to the appropriate source aperture geometry for the particular tissue model, from which the general acoustic pressure field distribution is obtained. The tissue transient and steady-state temperature increase are then calculated by applying the point-source solution of the bioheat transfer equation to the calculated field distribution.

The long-term objective is to further the state of the art of detecting defects that will compromise the integrity of new types of food packages by using a research team approach (experts in packaging, acoustic imaging, and challenge testing). The SLAM technology also operates at much higher frequencies (commercially available up to 500 MHz), thus providing the capability of achieving resolution limits of 4;gmm. The short-term objective of this pilot study is to identify the fundamental resolution limit by the Bioacoustics Research Laboratory's SLAM (operates at 100 MHz) of detecting packaging defects in order to develop a theoretical basis to improved image resolution capabilities.

The objective of the research program is to evaluate the feasibility for subsurface detection of cultural artifacts. The hypothesis is that subsurface artifacts can be detected using various acoustic imaging approaches. The principal unknowns are the axial and lateral spatial resolutions required as a function of buried artifacts in ground soil and the contrast resolution at which detection can be achieved for various soil types and conditions.

One-dimensional (linear) array transducers are used with virtually every diagnostic ultrasound imaging system with major efforts to develop efficient 2-D array transducers. Array imaging requires a medium with a homogeneous propagation speed to yield the optimal resolution. However, phase aberration results from tissue microstructure inho mogeneities, which seriously degrades the focusing of the ultrasonic beam and thus limits the resolution of modern ultrasonic imaging systems. This study aims to solve the 3-D (spatial) or 4-D (spatial and temporal) acoustic wave equation in a medium of variable propagation speed and density with the finite-difference time domain (FDTD) method and to analyze the time delay dependence of ultrasonic pulses on the tissue properties.

The longer service life of structures such as pipelines means that they must be monitored for damage more thoroughly and over a longer period of time. Using coupled surface waves may be one way to inspect the inner (not easily accessible) surface of a pipe from its outer surface. Moreover, if the damage were a small surface-breaking fatigue crack, then a surface wave would readily detect the crack because the surface wave would strike the crack broadside, or if the damage were corrosion, then a surface wave would be more severely attenuated by the patch of corrosion at the surface than a bulk wave. The study aims to evaluate coupled surface waves so that they can be used for such nondestructive testing.

T ypical real-time ultrasonic imaging is performed with phased array ultrasonic transducers using the ultrasonic backscattered signal. Previously we demonstrated that ultrasonic backscattered signal evaluation can detect packaging defects better than the system's resolution limit. This was accomplished with the development of a new pulse-echo image processing strategy called BII (backscattered integrated imaging)-mode imaging. These images were constructed under laboratory (static) conditions with off-line computer processing (nonreal-time processing). The research aim is to evaluate the extent to which the BII-mode pulse-echo technique can detect and classify packaging defects under real-time, production-line speed conditions.

Applications for microelectrical-mechanical systems (MEMS) which are being developed include low-cost microoptical mechanical switches for telecommunications, mechanical devices for microsurgery, and masks for biological molecule deposition. This project is aimed at high-force and displacement devices, as well as using dissimilar materials and creating 3-D utility from planar elements. One approach is to combine wafer-scale and laser-material processing to join elements which cannot be fabricated in the same process as silicon. Research in silicon and laser-material processing is currently being developed to solve the fundamental issues of MEMS.

Neuronal pattern analysis documents the dynamic brain processes of sensation, perception, learning, and cognition by recording the electrical activity of brain neurons. Recent advances in multiarray recording have greatly expanded the rate at which these data can be obtained, making possible the study of dynamic intercorrelations in neuronal networks. Computational modeling has fostered major increments in data-processing requirements, which call for parallel development of adequate database systems for organization, rapid access, and sharing of these data. This work establishes a database system for time series neurophysiological data recorded by the Neuronal Pattern Analysis Group at the Beckman Institute, carried out with collaboration from the National Center for Supercomputing Applications.

Neural net and other pattern recognition techniques are to be used to analyze Fourier transform infrared photo acoustic spectroscopic (FTIR-PAS) data from samples of corn in order to automate the detection of contaminated corn.

We propose to use morphological and morphometric, electrophysiological, immunocytochemical, and behavioral methods in mature adult and aging cerebellar cortex to determine which synapse and neuron types in cerebellar cortex exhibit plasticity in response to learning and to physical exercise; which nonneuronal elements exhibit plasticity; the molecular mechanisms underlying this plasticity; and functional correlates.