|
|
|
BRL Abstracts Database |
Your search for ultrasound produced 3296 results. Page 131 out of 330
Title |
Further skeptical comment on reported adverse effects of alleged low intensity ultrasound |
Author |
Edmonds PD. |
Journal |
Proc Twenty-fifth Annu Meet AIUM - New Orleans |
Volume |
|
Year |
1980 |
Abstract |
No abstract available. |
Title |
Further studies of the transkull transmission of an intense focused ultrasonic beam: Lesion production at 500 kHz. |
Author |
Fry FJ, Goss SA. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
1980 |
Abstract |
Focal lesions in lucite blocks and live brain tissue produced by an intense focused 500 kHz ultrasonic beam which had first been transmitted through an excised adult human skull section (formalin fixed) are described. The incident acoustic intensities ranged from about 880 to 1200 W/cm(^2) with exposure duration of 5-6 sec. The character of such lesions suggest that essential focal beam dimensions and temporal coherence of the sound wave were preserved with minimal distortion after transmission through this particular skull section (7-8 mm thickness over the region of sound transmission), which has been determined to exhibit sound intensity losses of about 16 dB at 500 kHz. There appears to be little heating of the skull section during irradiation at this incident intensity. |
Title |
Further studies on acoustic impedance of major bovine blood vessel walls. |
Author |
Geleskie JV, Shung KK. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1982 |
Abstract |
Data on ultrasound velocity and specific impedance of major bovine blood vessel walls are compared to structural protein content measured by hydroxypoline assay as well as total solid tissue content of these tissues. Results indicate that acoustic velocity in these tissues is determined largely by the collagen and elastin contents of the tissues. However, acoustic impedance, which is the product of density and velocity, shows a stronger dependence on the total tissue content, suggesting that other solid tissues, in particular, muscle in blood vessel walls, may also play a significant role in the determination of acoustic impedance. |
Title |
Gas-body-based contrast agent enhances vascular bioeffects of 1.09 MHz ultrasound on mouse intestine. |
Author |
Miller DL, Gies RA. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
1998 |
Abstract |
Anesthetized hairless mice were exposed to continuous or pulsed 1.09-MHz ultrasound with or without prior injection of a gas-body-based ultrasound contrast agent. Albunex at a dose of 10 mL/kg increased the production of intestinal hyperemia, petechia and hemorrhages by continuous ultrasound. For pulsed ultrasound, with 10 microsecond pulses and 0.01 duty cycle, petechiae were produced for exposures as low as 1 MPa spatial peak pressure amplitude with added gas bodies. The enhancement of petechiae production was robust for pulsed exposure; for example, at 2.8 MPa, an average of 227 petechiae was obtained with added gas bodies, which was 30 times more than without the agent. The production of petechia was roughly proportional to the dosage of Albunex for pulsed exposure. Results did not appear to be strongly dependent on pulsing parameters, but long bursts (0.1 s) were somewhat more effective than pulses (10 microsecond). The observed vascular bioeffects appeared to involve both thermal and nonthermal mechanisms for continuous exposure, but to result primarily from gas-body activation for pulsed exposure. |
Title |
Gauging the likelihood of cavitation from short-pulse, low-duty cycle diagnostic ultrasound. |
Author |
Apfel RE, Holland CK. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
1991 |
Abstract |
Although no deleterious effects form diagnostic ultrasound have been reported in epidemiologic studies and surveys of widespread.clinical usage (Ziskin and Petitti 1988), the conditions for the onset of transient cavitation must be investigated in the total.evaluation of potential risks associated with diagnostic ultrasound applications. An extension of the results from the approximate.theory developed by Holland and Apfel (1989) is applied in this paper to a population of nuclei to predict the onset of cavitation in.host fluids with physical properties similar to those of biological fluids. From this analysis and from results of recent in vitro.cavitation experiments, an index is developed which can gauge the likelihood of substantial microbubble growth in the presence of.short-pulse, low-duty cycle diagnostic ultrasound. . |
Title |
Gene therapy progress and prospects:Ultrasoud for gene transfer. |
Author |
Newman CMH,Betinger T. |
Journal |
Gene Ther |
Volume |
|
Year |
2007 |
Abstract |
Ultrasound exposure (USE) in the presence of microbubbles (MCB) (e.g. contrast agents used to enhance ultrasound imaging) increases plasmid transfection efficiency in vitro by several orders of magnitude. Formation of short-lived pores in the plasma membrane ('sonoporation'), up to 100 nm in effective diameter lasting a few seconds, is implicated as the dominant mechanism, associated with acoustic cavitation. Ultrasound enhanced gene transfer (UEGT) has also been successfully achieved in vivo, with reports of spatially restricted and therapeutically relevant levels of transgene expression. Loading MCB with nucleic acids and/or disease-targeting ligands may further improve the efficiency and specificity of UEGT such that clinical testing becomes a realistic prospect. |
Title |
Gene transfection and drug delivery. |
Author |
Miller MW. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
2000 |
Abstract |
No abstract available. |
Title |
Generalized description and tracking estimation of the frequency dependent attenuation of ultrasound in biological tissues. |
Author |
Cloostermans MJ, Verhoef WA, Thijssen JM. |
Journal |
Ultrason Imaging |
Volume |
|
Year |
1985 |
Abstract |
In this paper a general model for the attenuation in biological tissues is proposed. The model consists of a series expansion of the attenuation coefficient, thereby covering the whole range of frequency dependencies from zero to four. Therefore, effects like pure specular reflections and negligible absorption at one extreme, as well as attenuation due to Rayleigh scattering, at the other extreme, are incorporated. A technique is described to estimate the attenuation in the range of frequency powers in a sampled depth ranging form. The applicability of the technique is illustrated by the results of the simulation. |
Title |
Generation of coherent ultrasonic waves with gaAs gunn oscillator. |
Author |
Hayakawa H, Ishiguro T, Mikoshiba N, Kikuchi M. |
Journal |
Appl Phys Lett |
Volume |
|
Year |
1969 |
Abstract |
The experimental success in the generation of coherent ultrasonic waves from a GaAs Gunn oscillator with a dc pulse is reported. The frequency of the ultrasound is independent of the mechanical eigenfrequency of the oscillator. |
Title |
Generation of transient cavities in liquids by microsecond pulses of ultrasound. |
Author |
Flynn HG. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1982 |
Abstract |
Calculations reported here show that small gas nuclei in a liquid acted on by microsecond ultrasonic pulses may grow into transient cavities that collapse violently. The maximum pressures and temperatures generated by such collapsing cavities are found in these calculations to be of the order of 1000 to 70000 bars and 1000 to 20000 degrees K. |
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
|
|
|
|