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 158 out of 330

Title Intracellular microcurrents caused by ultrasound waves.
Author El'Piner IE, Faikin IM, Basurmanova OK.
Journal Biofizika
Volume
Year 1964
Abstract No abstract available.


Title Intracellular temperature distribution produced by ultrasound.
Author Love LA, Kremkau FW.
Journal J Acoust Soc Am
Volume
Year 1980
Abstract The steady-state temperature profile of a biological cell exposed to ultrasound was calculated by solving the time-independent driven heat flow equation. Three concentric spheres with different thermal conductivities and acoustic absorption coefficients, immersed in a nonabsorbing infinite medium, were used to represent each cell in a dilute aqueous suspension exposed to ultrasound. The inner sphere represented the nucleus, the middle shell the cytoplasm, and the outer shell the plasma membrane. Using representative radii, absorption coefficients, and thermal conductivities, a steady-state temperature rise of 0.13 mK at the cell center was calculated for frequency 1 MHz and intensity 1 W/cm2. Two forms of temperature (T) dependence on distance ( r) from sphere center were calculated: (1) T = D - Er2 and (2) T = G + (F/r), where D, E, F, and G are constants which are determined by the intensity, sphere radii, thermal conductivities, and absorption coefficients. The inner sphere had form (1) dependence, the shells had both types of dependence, and the outside medium had form (2) dependence. Variation of the absorption and conductivity parameters indicated a stronger dependence of temperature on absorption coefficients than on thermal conductivities. Temperature rises greater than one degree were not obtained unless the intensity, absorption coefficient, or the inverse of the conductivity was increased by four orders-of-magnitude above the representative values used to calculate the 0.13-mK temperature rise.


Title Intracranial anatomy visualized in vivo by ultrasound.
Author Fry WJ.
Journal Invest Radiol
Volume
Year 1968
Abstract Ultrasonic visualization in vivo of anatomic features of the ventricles, cisterns, sulci and major blood vessels of the brain and the internal surface configuration of the cranial vault of the rhesus monkey, using recently developed instrumentation incorporating omnidirectional scanning, relief presentation and computer control of transducer positioning, data handling and display parameters, is illustrated. Results are presented in cross-sectional views of the tissue. In this study the acoustic energy had access to intracranial structures via an opening in the skull, but traversed the intact scalp, thus achieving separation of the problems associated with the traversal of bone from those concerned with identification of interfaces detectable by examining pulses alone. A resolution capability of 1 mm and an accuracy of localization of ?0.5 mm are achieved. All definitive echoes in the echograms are identified, and quantitative comparison of the anatomic information obtained with brain atlases is presented. The analytic determination of length scaling factors and relative angular orientation values for the subject's ultrasonically-viewed tissue cross sections and those of an atlas are also illustrated.


Title Intracranial temperature elevation from diagnostic ultrasound.
Author Barnett SB.
Journal Ultrasound Med Biol
Volume
Year 2001
Abstract Tissues of the central nervous system are sensitive to damage by physical agents, such as heat and ultrasound. Exposure to pulsed spectral Doppler ultrasound can significantly heat biologic tissue because of the relatively high intensities used and the need to hold the beam stationary during examinations. This has significant implications for sensitive neural tissue such as that exposed during spectral Doppler flow studies of fetal cerebral vessels. Recent changes in the FDA regulation allow delivery of almost eight times higher intensity into the fetal brain by ultrasound devices that incorporate an approved real-time output display in their design. In this situation, ultrasound users are expected to assess the risk/benefit ratio based on their interpretation of equipment output displays (including the thermal index, TI) and an understanding of the significance of biologic effects. To assist in the assessment of potential thermally mediated bioeffects, a number of conclusions can be drawn from the published scientific literature: the amount of ultrasound-induced intracranial heating increases with gestational age and the development of fetal bone; pulsed spectral Doppler ultrasound can produce biologically significant heating in the fetal brain; the rate of heating near bone is rapid, with approximately 75% of the maximum heating occurring within 30 s; blood flow has minimal cooling effect on ultrasound-induced heating of the brain when insonated with narrow focused clinical beams; the threshold for irreversible damage in the developing embryo and fetal brain is exceeded when a temperature increase of 4 degrees C is maintained for 5 min; an ultrasound exposure that produces a temperature increase of up to 1.5 degrees C in 120 s does not elicit measurable electrophysiologic responses in fetal brain; for some exposure conditions, the thermal index (TI), as used in the FDA-approved output display standard, underestimates the extent of ultrasound-induced intracranial temperature increase.


Title Intramembrane cavitation as a unifying mechanism for ultrasound-induced bioeffects.
Author Krasovitski B, Frenkel V, Shoham S, Kimmel E.
Journal Proc Natl Acad Sci USA
Volume
Year 2011
Abstract The purpose of this study was to develop a unified model capable of explaining the mechanisms of interaction of ultrasound and biological tissue at both the diagnostic nonthermal, noncavitational (<100 mW·cm−2) and therapeutic, potentially cavitational (>100 mW·cm−2) spatial peak temporal average intensity levels. The cellular-level model (termed “bilayer sonophore”) combines the physics of bubble dynamics with cell biomechanics to determine the dynamic behavior of the two lipid bilayer membrane leaflets. The existence of such a unified model could potentially pave the way to a number of controlled ultrasound-assisted applications, including CNS modulation and blood–brain barrier permeabilization. The model predicts that the cellular membrane is intrinsically capable of absorbing mechanical energy from the ultrasound field and transforming it into expansions and contractions of the intramembrane space. It further predicts that the maximum area strain is proportional to the acoustic pressure amplitude and inversely proportional to the square root of the frequency (Graphic) and is intensified by proximity to free surfaces, the presence of nearby microbubbles in free medium, and the flexibility of the surrounding tissue. Model predictions were experimentally supported using transmission electron microscopy (TEM) of multilayered live-cell goldfish epidermis exposed in vivo to continuous wave (CW) ultrasound at cavitational (1 MHz) and noncavitational (3 MHz) conditions. Our results support the hypothesis that ultrasonically induced bilayer membrane motion, which does not require preexistence of air voids in the tissue, may account for a variety of bioeffects and could elucidate mechanisms of ultrasound interaction with biological tissue that are currently not fully understood.


Title Intramyocardial variability in integrated backscatter: Effects of coronary occlusion and reperfusion.
Author Sagar KB, Rhyne TL, Warltier DC, Pelc L, Wann LS.
Journal Circulation
Volume
Year 1987
Abstract The present study was undertaken to characterize regional myocardial alterations of reflected ultrasound during the cardiac cycle in normal, ischemic, and postischemic reperfused myocardium. Time-averaged integrated backscatter (IB) and cardiac cycle-dependent amplitude modulation were measured from subepicardial, midmyocardial, and subendocardial regions of the left ventricular apex and the midportion of the right ventricular free wall under normal conditions (n = 5), after 1 hr of 100% acute left anterior descending (LAD) occlusion (n = 8), and after 15 min LAD occlusion plus 120 min reperfusion (n = 5) in anesthetized, ventilated open-chest dogs. A significant increase in time-averaged IB was observed in the subepicardium, the midmyocardium, and the subendocardium during ischemia and reperfusion, but there was no intramyocardial variability. Cardiac cycle-dependent amplitude modulation of IB was significantly higher in the normal subendocardium than in the subepicardium (4.3 +/- 0.6 vs 2.9 +/- 0.8 dB, p less than .01) and midmyocardium (2.8 +/- .05 dB, p less than .01). This transmural gradient in amplitude modulation was abolished during ischemia and reperfusion. We conclude that cardiac cycle-dependent amplitude modulation in IB has a transmural dependence in the normal myocardium and this is abolished during acute myocardial ischemia.


Title Intravascular mural thrombi produced by acoustic microstreaming.
Author Williams AR.
Journal Ultrasound Med Biol
Volume
Year 1977
Abstract A discrete portion of the wall of an intact blood vessel may be driven to oscillate at an ultrasonic frequency in vivo by the external application of a vibrating metal probe. The hydrodynamic forces generated within the local intravascular microstreaming field at the site of contact with the probe tip increase with increasing amplitude of oscillation of the ultrasonic driver. Under the appropriate experimental conditions one may produce (1) no detectable effects; (2) adhesion of platelets to apparently intact endothelium; (3) fibrin-free mural aggregates of platelets with the concomitant production of platelet micro-emboli; (4) mural thrombi of platelets permeated with fibrin and enveloped within a mixed clot and (5) obvious damage to the vessel wall and its endothelium with widespread clot formation. This technique might be of use in the in vivo screening of drugs which may interact with the haemostatic system..


Title Intravascular therapeutic ultrasound thrombolysis in acute myocardial infarctions.
Author Hamm CW, Steffen W, Terres W, de Scheerder I, Reimers J, Cumberland D, Siegel RJ, Meinertz T.
Journal Am J Cardiol
Volume
Year 1997
Abstract Catheter-delivered, therapeutic ultrasound was shown to effectively dissolve thrombus in vitro and in vivo. This first study in 14 patients with acute myocardial infarctions demonstrates that it is a safe and effective treatment alternative that deserves further clinical evaluation.


Title Intravesical growth of murine bladder tumors assessed by transrectal ultrasound.
Author Alexander AA, Liu J, McCue P, Gomella LG, Ross RP, Lattime EC.
Journal J Urol
Volume
Year 1993
Abstract Experimental studies in the therapy of intravesically growing bladder tumors in mice have been hampered by an inability to monitor tumor growth before and during treatment. To establish a repeatable, noninvasive method to monitor the intravesical growth of bladder tumors, MB49 murine bladder tumor cells were instilled into the bladders of syngeneic C57BL/6 mice. Following 3 weeks of growth, the bladders of tumor-bearing and control mice were imaged using a 20 mHz, 6.2 F catheter-based ultrasound transducer inserted rectally. Bladders of tumor implanted and control mice were identified by high resolution endoluminal ultrasound after distension with 0.15 ml. of normal saline. When compared with the results of histologic analysis, transrectal ultrasound (TRUS) accurately identified tumor presence, size, and location.


Title Intrinsic spin-lattice relaxation rates in MgO:Fe(2+) from nonresonant ultrasonic measurements.
Author Yuhas MP, Bolef DI, Miller JG.
Journal Phys Rev B
Volume
Year 1978
Abstract Low-frequency nonresonant (delta m = 0) ultrasound has been used to measure the intrinsic direct and Orbach electron spin-lattice relaxation rates Gamma(0) in single crystal MgO:Fe(2+). The relaxation rates were determined from measurements of acoustic absorption and acoustical dispersion as a function of magnetic field and of temperature. Characteristics of nonresonant ultrasonic absorption and dispersion in MgO:Fe(2+) were studied experimentally and compared with predictions of theory. Comparable values of the relaxation rates were found for two specimens of MgO:Fe(2+) with Fe(2+) concentrations of 30 and 125 ppm. These, however, are not in agreement with values obtained by investigators using resonant techniques.


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