|
|
|
BRL Abstracts Database |
|
Your search for ultrasound produced 3296 results. Page 256 out of 330
| Title |
The effect of ultrasound on the transmissible Walker rat carcinoma. |
| Author |
Schroder JD, Herrick JF, Karlson AG |
| Journal |
Arch Phys Med |
| Volume |
|
| Year |
1952 |
| Abstract |
No abstract available. |
| Title |
The effect of various physical parameters on the size and shape of necrosed tissue volume during ultrasound surgery. |
| Author |
Damianou C, Hynynen K. |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
1994 |
| Abstract |
The purpose of this study was to test the concept of using calculated thermal dose as a predictor for the necrosed tissue volume. A parametric study was conducted where the sonication parameters (pulse duration, power), transducer parameters (frequency, F number) and tissue properties (perfusion rate, attenuation) were varied and their effect on the lesion size was investigated. In vivo experiments where a focused ultrasound beam was used to induce tissue necrosis in thigh muscle of dog and rabbit were also conducted to obtain the reliability of the predictions. The experimental and simulated lesion sizes compared well. From the parametric study the threshold intensity for 1- and 5-s sonications were found to be about 1000 and 400 W/cm2, respectively. It was found that the lesion size was practically perfusion independent for pulses 5 s or shorter. The lesion size increases with increased pulse duration, acoustical power, and F number, but decreases with increased frequency provided that the focal intensity is kept constant. It was found also that the deeper the focus is in the tissue, the smaller the frequency range that causes selective tissue necrosis in the focal zone. |
| Title |
The effect on cleavage of Arabica eggs of ultrasound applied to a small area of the cell surface. |
| Author |
Wilson WL,Schnitzler RM. |
| Journal |
Biol Bull |
| Volume |
|
| Year |
1963 |
| Abstract |
No abstract available. |
| Title |
The effects of 2H2O on the phase transition of large.unilamellar vesicle (LUV) suspensions as detected by ultrasound spectroscopy and electron spin resonance. |
| Author |
Ma LD, Magin RL, Bacic G, Dunn F. |
| Journal |
Biochim Biophys Acta |
| Volume |
|
| Year |
1989 |
| Abstract |
The importance of water in the molecular dynamics of large unilamellar vesicle (LUV) suspensions, in which increasing portions of the water were replaced by 2H2O, was.investigated. Determinations of the ultrasonic absorption coefficient per wavelength, alpha.lambda, were performed as a function of temperature and frequency for LUVs (LUVs: 4:1 (w/w).mixture of dipalmitoylphosphatidylcholine, DPPC, and dipalmitoylphosphatidylglycerol, DPPG).in the vicinity of their phospholipid phase transition, using a double crystal acoustic interferometer. Electron spin resonance (ESR) and differential scanning calorimetry (DSC) were also employed to probe this system. When increasing portions of the aqueous content of the LUV suspensions were replaced by 2H2O the phase transition temperature increased from 42.0 degrees C to 42.9 degrees C (indicating an increase in the activation energy of the transition), and the amplitude of alpha lambda at the phase transition increased. However, alpha lambda max as a.function of frequency at the phase transition did not change with the addition of 2H2O, indicating that the relaxation time of the event responsible for the absorption of ultrasound was unaffected. The increase in the activation energy of the transition with the addition of 2H2O suggested that the mobility of phospholipids near the membrane/aqueous interface was changed. Electron spin resonance (ESR) experiments on LUVs with nitroxide spin probes positioned at the membrane/aqueous interface (5-doxyl stearate and CAT16) showed that LUVs in 2H2O have a broader splitting, Amax, at the membrane/aqueous interface than do LUVs in H2O. These results suggest that 2H2O changes the mobility and/or structure of the phospholipids in the region of the membrane/aqueous interface. This difference in Amax was not seen for the probe PC-12-doxyl stearate, which resides at the C-12 position of the bilayer. |
| Title |
The effects of A23187 on the phospholipid phase transition of large unilamellar vesicles (LUVs) as detected by ultrasound spectroscopy. |
| Author |
Ma LD, Magin RL, Dunn F. |
| Journal |
Biochim Biophys Acta |
| Volume |
|
| Year |
1990 |
| Abstract |
The effect of the hydrophobic Ca2+ ionophore, A23187, on the phospholipid dynamics of large unilamellar vesicle (LUVs: 4: 1 (w/w) mixture of dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG] membranes, as a function of A23187.content, was investigated using techniques sensitive to the phospholipid phase transition. The ultrasonic absorption per wavelength, alpha lambda, was determined with a double crystal acoustic interferometer, as a function of temperature and frequency for LUVs in.the vicinity of their phospholipid phase transition. Differential scanning calorimetry (DSC) and electron spin resonance (ESR) were also employed to probe the thermodynamics and molecular environment of the hydrocarbon side chains. With increasing A23187 content, the phase transition temperature (Tm) of the LUV suspensions remained near 42.0 degrees C, while the amplitude of alpha.lambda at the phase transition increased dramatically. At Tm the relaxation frequency, where alpha lambda max occurs, decreased with A23187 content, suggesting that the relaxation rate of the event responsible for the absorption of ultrasound decreased. The ESR studies showed no change in the fluidity of the bilayer with the inclusion of 2 and 5 mol% A23187 in the C-12 region of the bilayer. Therefore, A23187 in LUV membranes slows the structural relaxation of the hydrocarbon side chains of the phospholipid bilayer at the phase transition. |
| Title |
The effects of biological tissues on 15-mc pulsed ultrasound. |
| Author |
Wild JJ, Reid JM. |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
1953 |
| Abstract |
The subject of this paper, which is mainly descriptive, grew out of the desire of a biologist to measure the thickness of the human bowel wall in the living intact subject. [J. J. Wild, Surgery 27, 183 (1950)]. The object was to justify certain methods of treatment for the suspected underlying mechanisms at work, the results of which are lumped together by surgeons under the title of bowel distension. The approach to the subject has been almost entirely biological, not ignoring, however, the theory of sound where applicable. It will be seen that biological methods of control are used as a first approximation in order to justify more detailed examination of the system. Some of the difficulties of the exact approach from theory will be discussed after presentation of the experimental theory will be discussed after presentation of the experimental facts. It may be of interest to the more exact-thinking members of the audience to note that a system having a nightmare of complexity to the physicist may be considered simple by the biologist in his blissful ignorance. This situation is perhaps fortunate because otherwise the biologist might be tempted to give up too easily. It is the duty of the biologist to try to simplify complex phenomena so that his more able colleagues in more exact branches of science will be stimulated to "pitch in" and help. We hope that today we shall be able to bring about this desirable end and succeed in stimulating more workers to investigate this field. It should, however, be realized at the outset that the increasing exploitation of the observed phenomena does not necessarily need to wait upon whatever fundamental explanations may be forthcoming. The experimental results will not necessarily be presented in chronological sequence but an attempt will be made to present some of our collected experimental data in as logical a manner as possible. |
| Title |
The effects of continuous wave and pulsed ultrasound on rat thymocytes in vitro. |
| Author |
Dooley DA, Child SZ, Carstensen EL, Miller MW. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1983 |
| Abstract |
Rat thymocytes in suspension were exposed to continuous wave and pulsed ultrasound at frequencies of 0.5 and 1 MHz. In qualitative confirmation of the observations of Chapman et al. (1979), cell lysis and cell survival were found to depend upon ultrasound intensity, frequency and time of exposure. Cell survival.after 10 min, 2 W/cm2, 0.5 MHz was approx. 40 percent of control. Pulsed exposures at 0.5 MHz with the same temporal average intensity but with a temporal peak intensity of 30 W/cm2 showed no statistically significant decrease in survival in comparison with controls. The thymocyte observations provide no support for the belief that diagnostic ultrasound may cause biological effects in the fluids of the body. |
| Title |
The effects of diagnostic ultrasonography on the frequencies of sister chromatid exchanges in Chinese hamster cells and human lymphocytes. |
| Author |
Wegner RD, Meyenburg M. |
| Journal |
J Ultrasound Med |
| Volume |
|
| Year |
1982 |
| Abstract |
Human lymphocytes as well as Chinese hamster ovary cells were sonicated with either a fetal pulse detector (Siemens, Eucotone) or a compound scanner (Kretz, Combison 4100) at diagnostic energy levels. In one experimental series the cells.were treated in the G1-phase of the cell cycle, in the other during late S-phase. The frequency of sister chromatid exchanges was determined in the metaphase chromosomes of the following mitosis. No significant increase in the frequency of SCEs per cell was observed as compared with the controls. |
| Title |
The effects of high intensity ultrasound on the ultrastructure of mammalian central nervous tissue. |
| Author |
Borrelli MJ. |
| Journal |
Thesis(PhD): Univ of Illinois |
| Volume |
|
| Year |
1984 |
| Abstract |
No abstract available. |
| Title |
The effects of high intensity ultrasound on the ultrastructure of mammalian central nervous tissue. |
| Author |
Borrelli MJ. |
| Journal |
Thesis(MS): Univ of Illinois |
| Volume |
|
| Year |
1984 |
| Abstract |
No abstract available. |
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
|
|
|
|
