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 191 out of 330

Title On the measurement of frequency dependent attenuation in biological tissues using broadband pulsed ultrasound.
Author Akiyama I, Nishida Y, Nakajima M, Yuta S.
Journal Proc Ultrason Symp IEEE
Volume
Year 1983
Abstract It is expected that biological tissues can be characterized by the ultrasound transmission measurement of frequency dependant attenuation (FDA) of the tissue specimen. This method could be performed by comparing the amplitude of the transmitting wave with the incident wave at every frequency. We can use either a continuous sinusoidal wave (CW) or a broadband pulsed ultrasound wave. We experimentally measured the frequency vs. attenuation curve by these techniques, and observed the following inexplicable phenomenon. It is that we observed in CW measurement, whenever the pulse transmission technique was adopted. As well as we found the similar relation in some data of the previous other works. We discussed this phenomenon by computer simulations and it is confirmed that this phenomenon results in the waveform distortion according of a finite amplitude sound wave propagation.


Title On the mechanism of biological effects produced by ultrasound.
Author Hueter TF.
Journal Chem Eng Prog Symp Ser
Volume
Year 1951
Abstract No abstract available.


Title On the quenching of ultrasonic waves in aqueous solutions of nucleic acids.
Author El'Piner IE, Sadikhova SK, Braginskaya FI.
Journal Biofizika
Volume
Year 1970
Abstract There was studied the absorption of ultrasonic energy by the solutions of nucleic acids, native ones and under various exposures (chemical agents, heat, ultrasound of high intensity). An impluse device with working range of 12-68 mcycles/sec was used for measuring. The studies enabled the following conclusion. The change of the secondary structure of RNA molecules by some chemical agents (formaldehyde, hydroxylamine) results in the increased absorption of ultrasonic waves, while the breakes of the polymer chain under ultrasonic effect of high intensity, or induced by hydrolisis or urea bring about the reduced quenching of acoustic energy in the fequency range studied.


Title On the role of shear viscosity in mediating inertial cavitation from short-pulse, megahertz-frequency ultrasound.
Author Allen JS, Roy RA, Church CC.
Journal IEEE Trans UFFC
Volume
Year 1997
Abstract Pressure thresholds for inertial cavitation in water and biological media modeled as a viscous fluid are calculated using a numerical implementation of the Gilmore equation for adiabatic bubble oscillations. The threshold criterion is chosen to be a bubble collapse temperature of 5000 K in order to facilitate comparison with the analytical theory of others. There is a trend toward increasing pressure thresholds with increasing frequency and/or viscosity. The frequency dependence of the inertial cavitation pressure threshold becomes more pronounced as the fluid viscosity is increased. There is a clear indication of two regimes of bubble behavior in which “small” and “large” bubbles exhibit elevated thresholds due to surface tension and mass loading, respectively. The “nonlinear resonance size” demarcates these two regimes and provides a descriptor of the initial bubble sizes most likely to undergo inertial cavitation for a given frequency and viscosity. The physical effects of the liquid's viscosity on the subsequent bubble dynamics are discussed and comparison made with experimental measurements.


Title On the suitability of broadband attenuation measurement for characterizing contrast microbubbles.
Author Chatterjee D, Sarkar K, Jain P, Schreppler.
Journal Ultrasound Med Biol
Volume
Year 2005
Abstract previous termBroadband attenuation measurementnext term has been widely used previous termfor characterizingnext term ultrasound previous termcontrastnext term agents. Chen et al. (2002) recently suggested that previous termbroadband attenuationnext term data depend on the center frequency of the previous termbroadbandnext term excitation pulse and, therefore, that they are not a reliable measure of the bubble behavior. We investigated the previous termsuitability of measurement of broadband attenuationnext term as a previous termcharacterizingnext term tool using the previous termcontrastnext term agent Definity® as a test case. Analyzing the previous termattenuationnext term data obtained with three previous termbroadbandnext term unfocused transducers with different center frequencies (2.25, 3.5 and 5 MHz), we found that previous termattenuationnext term is independent of the transducer used and matches in the overlap regions of any two transducers. previous termAttenuationnext term does not depend on excitation pressure amplitude as long as the excitation amplitude remains below a critical value (≈ 0.26 MPa), indicating that the previous termmeasurement of broadband attenuationnext term below critical excitation can, indeed, be used previous termfornext term characterization. Furthermore, the linear relationship of previous termattenuationnext term with concentrations of Definity® is also investigated.


Title On the ultrasound diffraction losses for circular transducers of different radii.
Author Khimunin AS.
Journal Acustica
Volume
Year 1983
Abstract Qualitative relationships are analysed in the behaviour of average pressure on a receiver of radius b, located in the near-field of a radiator of radius a. Some new relationships are found in the behaviour of the transfer factor of such an acoustic system in terms of the distance between transducers. In particular, the proportionality of responses was established for two coaxial acoustic systems with two equi-dimensional pairs of transducers (a1 = b2 and b1 = a2) which can be utilized for transducer calibration purposes. Simple relations are discussed for defining the maximum permissible size of a measuring hydrophone according to a given reproducibility error for a field structure under investigation. The results of experimental research are presented in the behaviour of average acoustic pressure for various relations between the dimensions of a radiator and a receiver.


Title On the ultrasound scattering from blood as a function of hematocrit.
Author Shung KK.
Journal IEEE Trans Sonics Ultrason
Volume
Year 1982
Abstract Volumetric ultrasonic scattering coefficient for blood defined as the power scattered per unit volume of erythrocytes per unit incident intensity has been measured as a function of frequency and hematocrit. An experimental scattering peak was observed to occur at a hematocrit between 20 percent and 30 percent for all frequencies investigated. This is not in good agreement with Twersky?s earlier theories which assumed independent scatterers and predicted a maximum at 50 percent. This assumption certainly does not apply to blood with large fractional volume of erythrocytes (hematocrit greater than 8 percent). To consider interactions among scatterers at large fractional volume, pair distribution function of scatterer positions must be specified. A number of approximations for this function have been developed. Pair distribution functions derived by Twersky using theorems in statistical mechanics, which also could be obtained from Percus-Yevick equation, are used to describe the experimental ultrasonic scattering data on blood. It is shown that the shift of the scattering peak from a hematocrit of 50 percent to lower hematocrits is not unexpected and could be explained in terms of the interaction among scatterers.


Title On the use of ultrasound for tumor detection.
Author Ballantine HT Jr., Hueter TF, Bolt RH.
Journal J Acoust Soc Am
Volume
Year 1954
Abstract Results are reported on recent investigations to test the possibility of detecting brain tumors by ultrasonic scanning. It is concluded that though compensated ultrasonograms (sound shadow pictures) may contain some information on brain structure, they are too sharply ?noise? limited to be of unqualified clinical value. Letter to the editor.


Title On the usefulness of the mechanical index displayed on clinical ultrasound scanners for predicting contrast microbubble destruction.
Author Forsberg F, Shi WT, Merritt CR, Dai Q, Solcova M, Goldberg BB.
Journal J Ultrasound Med
Volume
Year 2005
Abstract OBJECTIVE: The purpose of this study was to evaluate the mechanical index (MI) displayed on clinical ultrasound scanners as a predictor of exposure conditions related to the destruction of sonographic microbubble contrast agents. METHODS: Sonazoid (GE Healthcare, Oslo, Norway) and Optison (GE Healthcare, Princeton, NJ) microbubbles were injected into a tissue-mimicking flow phantom. Gray scale imaging was performed with 4 different scanners and 3 different transducers (3.5 MHz curved linear, 2.5 MHz convex, and 7.5 MHz linear array), and the MI displayed by the scanner was varied from 0.2 to 1.5 by changing the system output power. All other scanning parameters were kept constant. Downstream changes in echogenicity were monitored with a PowerVision 7000 scanner (Toshiba America Medical Systems, Tustin, CA) as an indirect measure of bubble destruction. Video intensity changes within the flow tube were determined as a function of MI for the different scanner/transducer combinations, and the best linear fit was determined. RESULTS: At a displayed MI of 0.7, different scanner/transducer combinations exhibited a range in video intensity from +16% to -3% of baseline for Sonazoid and from +8% to -71% for Optison. At an MI of 0.3, reductions in video intensity of up to 32% were produced. These results indicate a wide range in bubble destruction at identical MI values. Likewise, regression analysis found no linear fits for all scanner/transducer combinations (r2 < 0.046). CONCLUSIONS: The MI displayed on clinical ultrasound scanners does not predict the degree of microbubble destruction and should not be used by itself to define exposure conditions for destruction of microbubble contrast agents.


Title On viscoelastic models of the cell membrane.
Author Lewin PA, Chivers RC.
Journal Acoust Lett
Volume
Year 1980
Abstract Some evidence for the viscoelasticity of cell membranes is presented and a Burgers model is proposed as the basis of a discussion of the biological effects of pulsed ultrasound. Using the inadequate data available in the literature, a minimum relaxation time of 0.2 sec is obtained, which differs significantly from an experimental estimate for liver tissue of 300 ?s. The causes of the difference are discussed, and a series of experiments is suggested which may elucidate potential mechanical mechanisms connected with the repetition frequency of the pulses used for irradiation.


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