Bioacoustics Research Lab
University of Illinois at Urbana-Champaign | Department of Electrical and Computer Engineering | Department of Bioengineering
Department of Statistics | Coordinated Science Laboratory | Beckman Institute | Food Science and Human Nutrition | Division of Nutritional Sciences | College of Engineering
 Friday, March 29th, 2024
BRL Home
About BRL
Publications
Projects
People
History
Facilities
Abstracts Database
Seminars
Downloads
Archives
Bioengineering Research Partnership
William D. O'Brien, Jr. publications:

Michael L. Oelze publications:

Aiguo Han publications:

BRL Abstracts Database

Search - a quick way to search the entire Abstracts Database.
 
Advanced Search - search specific fields within the Abstracts Database.
Title
Author
Journal
Volume
Year
Abstract Text
Sort by:     Title     Author     Journal     Year
Number of records to return:     10     20     30     50

Your search for ultrasound produced 3296 results.

Page 281 out of 330

Title Transient excitation of insonated bubbles.
Author Leighton TG.
Journal Ultrasonics
Volume
Year 1989
Abstract When a previously non-oscillating bubble is first insonated, its radical motion can contain transients. Before the oscillation settles down to the steady-state, these transients may enhance the violence of the volume pulsations. The temperature attained within the bubble can be much greater than that reached during the steady-state motion. This phenomenon may contribute to the increased cavitational effects (such as sonoluminescence or ultrasonic bioeffects) observed when ultrasound is pulsed, and when the transducer and liquid sample are in relative motion.


Title Transient modification of membrane potential and conductance by single ultrasound bursts modulates neuronal excitability.
Author Mihran RT, Barnes FS, Wachtel H.
Journal Proc Twelfth Annu Int Conf IEEE Eng Med Biol Soc
Volume
Year 1990
Abstract The effect of short ultrasound bursts on the electrochemical characteristics of both myelinated and unmyelinated nerves was studied in vitro. These studies have revealed excitability changes occurring in a window of 40-50 ms following a single submillisecond exposure, which include periods of both relative enhancement and suppression of excitability. These modulations of excitability have now been associated with changes of membrane rest potential and conductance, as measured with intracellular electrodes. It is postulated that the radiation pressure transient accompanying the envelope of the acoustic pulse is the effective field parameter in this phenomenon, and may act by the gating of stretch-sensitive channels in the membrane.


Title Transient pulsations of small gas bubbles in water.
Author Flynn HG,Church CC.
Journal J Acoust Soc Am
Volume
Year 1988
Abstract Transient behavior of small gas bubbles in a liquid set into violent motion by ultrasonic pressure waves is of interest because of widespread use of microsecond pulses in diagnostic ultrasound. Such pulses contain only a few pressure cycles and the transient pulsations of bubbles set in motion by such pulses would determine the bubble–ultrasound interaction. A computer study has been made to obtain a global representation of the pulsation amplitudes R(t) of small gas bubbles (nuclei) in water during the first few cycles of a cw ultrasonic pressure. One objective was to obtain a better understanding of cavitation phenomena where many nuclei with initial radii Rn from 0.1–20 µm are set in motion at pressures ranging from 0.5–5 bars and at frequencies from 0.1–10 MHz. Results allowed construction of surfaces showing the relative bubble amplitude R/Rn as a function of Rn and of the time t/TA, where TA is the acoustic period. One finding is that, in the range of peak pressures found in diagnostic pulses, transient cavities would be generated during the first pressure cycle from nuclei with initial radii as small as a few microns (µm). Nuclei that grow into transient cavities in the first pressure cycle are here called ``prompt'' nuclei. At a specified pressure, the size range of radii Rn in which they occur decreases with increasing frequency. At 5 bars, the range of Rn for prompt nuclei is 0.166–11.35 µm at 0.5 MHz and vanishes at 10 MHz.


Title Transient pulsations of small gas bubbles in water.
Author Flynn HG, Church CC.
Journal J Acoust Soc Am
Volume
Year 1988
Abstract Transient behavior of small gas bubbles in a liquid set into violent motion by ultrasonic pressure waves is of interest because of widespread use of microsecond pulses in diagnostic ultrasound. Such pulses contain only a few pressure cycles and the transient pulsations of bubbles set in motion by such pulses would determine the bubble-ultrasound interaction. A computer study has been made to obtain a global representation of the pulsation amplitudes R (t) of small gas bubbles (nuclei) in water during the first few cycles of a cw ultrasonic pressure. One objective was to obtain a better understanding of cavitation phenomena where many nuclei with initial radii Rn from 0.1-20 microns are set in motion at pressures ranging from 0.5-5 bars and at frequencies from 0.5-10 MHz. Results allowed construction of surfaces showing the relative bubble amplitude R/Rn as a function of Rn and of the time t/TA, where TA is the acoustic period. One finding is that, in the range of peak pressures found in diagnostic pulses, transient cavities would be generated during the first pressure cycle from nuclei with initial radii as small as a few microns (micron). Nuclei that grow into transient cavities in the first pressure cycle are here called "prompt" nuclei. At a specified pressure, the size range of radii Rn in which they occur decreases with increasing frequency. At 5 bars, the range of Rn for prompt nuclei is 0.166-11.35 microns at 0.5 MHz and vanishes at 10 MHz.


Title Transkull transmission of an intense focused ultrasonic beam.
Author Fry FJ.
Journal Ultrasound Med Biol
Volume
Year 1977
Abstract An intense focused ultrasonic beam was used in the transkull transmission mode to produce focal thermal ?lesions? in a lucite block. This result was accomplished with a 1 MHz beam transmitted through an excised adult human skull section which had been shown by low intensity measurements to have 13 dB attenuation of sound pressure at this frequency. The essential focal beam dimensions and temporal coherence of the sound wave have been preserved at this frequency after transmission through this particular skull. Other studies indicate that no adult human skull should have a higher attenuation value at a frequency of 500 kHz than this skull shows at 1 MHz.


Title Transkull transmission of axisymmetric focused ultrasonic beams in the 0.5 to 1 MHz frequency range: Implications for brain tissue visualization, interrogation, and therapy.
Author Fry FJ.
Journal Proc Second Int Symp Ultrason Tissue Character
Volume
Year 1977
Abstract In order for ultrasound to become a practical clinical technique for diagnosis of many intracerebral diseases in the adult human, it has been necessary to answer questions concerning insertion loss of skull, temporal, and spatial characteristics of beams operating in the 0.5 to 1.0 MHz range (the requisite frequency is a function of the particular adult skull) have a maximum single pass skull insertion loss of nearly 10 dB (20 dB for a pulse echo system) which can be handled with present techniques to provide adequate signal strength from normal and pathological features of brain. In this frequency range, for skulls in our studies, the appropriately selected frequency is unchanged after double pass skull transmission, the 6 dB beam width is increased by a maximum of 40 percent and the beam focus is shifted laterally by a maximum of 3 mm. Resolution of string targets or live brain targets has been demonstrated to be in the 2 to 3 mm range at 1 MHz and at 0.5 MHz it appears that 4 to 6 mm resolution can be achieved. A high intensity focused ultrasonic beam (1 MHz) has been transmitted through an excised adult skull and used to produce a focal thermal flaw in lucite. This simultaneous test indicates that the induction of transkull focal lesions in live adult brain may now be possible.


Title Transkull visualization of brain using ultrasound: an experimental model study.
Author Fry FJ, Eggleton RC, Heimburger RF
Journal Proc Second World Congr Ultrason Med - Rotterdam
Volume
Year 1973
Abstract No abstract available.


Title Transmission of auditory information to man by means of focused ultrasound.
Author Gavrilov LR, Tsirul'nikov EM.
Journal Proc Tenth Int Congr Acoust - Sidney
Volume
Year 1980
Abstract No abstract available.


Title Transmission of ultrasound through living human thorax.
Author Crawford HD, Wild JJ, Wolf PI, Fink JS.
Journal IRE Trans Med Electron
Volume
Year 1959
Abstract Experiments are described demonstrating the passage of one-mic/sec continuous wave ultrasound through the heart and lungs at power levels of 100 mw/cm^2 at the transducer terminals (a total of 1.25 watts). When the sound was directed through the region of the heart, the ultrasound was modulated by the moving intra-thoracic structures in synchronism with the heart beat. The records obtained were modified both by exercise and by amyl nitrtite administered to the subject, but remained synchronous with the heart rate. Modulation of the ultrasound did not occur in two warm corpses. Sonic energy at the levels used to traverse the thorax did not affect a simultaneously recorded electrocardiogram. Nodeleterious effects have been observed on a subject whose heart was irradiated at 1 watt/cm^2 and 3 watts/cm^2 (totals of 12.5 and 37.5 watts, respectively) applied to transducer terminals at intervals over a aperiod of one year. When continuous wave ultrasound was directed through a lung field clear of the heart, it was found that the attenuation varied 50 db between full inspiration and a lung emptying of 3400 cubic cm (0 db = full inspiration). In addition to direct transmission, sound is scattered throught the thorax. The mechanics of the ultrasonic phenomena are described.


Title Transmission-reflection technique for measurement of frequency characteristics of ultrasound attenuation constant.
Author Soetanto K, Tanaka M, Ohtsuki S, Okujima M.
Journal Jpn J Appl Phys
Volume
Year 1987
Abstract A technique for obtaining the attenuation constant alpha and its frequency characteristics from the echo signal of a point reflector is proposed. Experiments were conducted using specimens of fine glass balls dispersed in agar and gelatin as an ultrasonic medium. The experimentally obtained value of alpha was close to the data obtained by relative attenuation technique.


Page 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107 | 108 | 109 | 110 | 111 | 112 | 113 | 114 | 115 | 116 | 117 | 118 | 119 | 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 | 128 | 129 | 130 | 131 | 132 | 133 | 134 | 135 | 136 | 137 | 138 | 139 | 140 | 141 | 142 | 143 | 144 | 145 | 146 | 147 | 148 | 149 | 150 | 151 | 152 | 153 | 154 | 155 | 156 | 157 | 158 | 159 | 160 | 161 | 162 | 163 | 164 | 165 | 166 | 167 | 168 | 169 | 170 | 171 | 172 | 173 | 174 | 175 | 176 | 177 | 178 | 179 | 180 | 181 | 182 | 183 | 184 | 185 | 186 | 187 | 188 | 189 | 190 | 191 | 192 | 193 | 194 | 195 | 196 | 197 | 198 | 199 | 200 | 201 | 202 | 203 | 204 | 205 | 206 | 207 | 208 | 209 | 210 | 211 | 212 | 213 | 214 | 215 | 216 | 217 | 218 | 219 | 220 | 221 | 222 | 223 | 224 | 225 | 226 | 227 | 228 | 229 | 230 | 231 | 232 | 233 | 234 | 235 | 236 | 237 | 238 | 239 | 240 | 241 | 242 | 243 | 244 | 245 | 246 | 247 | 248 | 249 | 250 | 251 | 252 | 253 | 254 | 255 | 256 | 257 | 258 | 259 | 260 | 261 | 262 | 263 | 264 | 265 | 266 | 267 | 268 | 269 | 270 | 271 | 272 | 273 | 274 | 275 | 276 | 277 | 278 | 279 | 280 | 281 | 282 | 283 | 284 | 285 | 286 | 287 | 288 | 289 | 290 | 291 | 292 | 293 | 294 | 295 | 296 | 297 | 298 | 299 | 300 | 301 | 302 | 303 | 304 | 305 | 306 | 307 | 308 | 309 | 310 | 311 | 312 | 313 | 314 | 315 | 316 | 317 | 318 | 319 | 320 | 321 | 322 | 323 | 324 | 325 | 326 | 327 | 328 | 329 | 330