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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 238 out of 330
| Title |
Stress-wave-induced membrane permeation of red blood cells is facilitated by aquaporins. |
| Author |
Lee S, McAuliffe DJ, Zhang H, Xu Z, Taitelbaum J, Flotte TJ, Doukas AG. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1997 |
| Abstract |
Stress waves generated by lasers and extracorporeal lithotripters have been shown to transiently increase the permeability of the plasma membrane, without affecting cell viability. Molecules present in the medium can diffuse into the cytoplasm under the concentration gradient. Molecular uptake under stress waves correlates with the presence of functioning aquaporins in the plasma membrane.
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| Title |
Structural and functional changes in the cochlea following ultrasonic irradiation. |
| Author |
Barnett SB. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1980 |
| Abstract |
Following ultrasonic irradiation of the cochlea cellular damage was observed within the hair cells of the organ of Corti and in the stria vascularis. The outer hair cells were more susceptible to damage than the inner hair cells. These immediate morphological changes did not occur when the intracochlear temperature was raised in the absence of ultrasound. Functional changes were determined from measurements of the cochlear microphonic response and the endolymphatic potential during ultrasonic irradiation. Cochlear irradiation produced a permanent depression in the positive E.P. In addition a depression in the microphonic response occurred which comprised two distinct phases the slower of which was reversible. The permanent depression resulted from the combined effect of ultrasonic and thermal energy. The reversible change may be due to restriction in the energy available to the organ of Corti resulting from the influence of ultrasound on the stria vascularis. |
| Title |
Structural characteristics of protein gels as determined by an ultrasound imaging technique. |
| Author |
Acton JC, Clay DL, Robinson KE, Dick RL, Acton WC. |
| Journal |
J Food Sci |
| Volume |
|
| Year |
1986 |
| Abstract |
Structural density features of gels formed with gelatin, egg albumen, and poultry thigh natural actomyosin were determined with an ultrasound system equipped with a real time monitor, imager, and photographic unit. Echo recordings of the acoustic impedance showed that all protein gels were similar in respect to structural density differential patterns. Increases in protein concentration increased the net area occupied by protein junctions and interlinks. The ultrasound imaging technique confirmed the aggregated junction, interlink, and interstitial regions that are common features of protein gels. |
| Title |
Structural studies of fibrinogen by ultrasound irradiation. |
| Author |
Albert A, Ayuso MR, Usobiaga P. |
| Journal |
Thromb Diath Haemorrh |
| Volume |
|
| Year |
1975 |
| Abstract |
Low frequency ultrasound irradiation of purified fibrinogen solutions produces a precipitation of protein and a loose on clottability due to molecular fragmentation, both depending in different ways on the irradiation dose. Precipitation seems to be closely related to free radical formation, the fragmentation being due mainly to the shearing forces appearing during cavitation. The high molecular weight fragments obtained by ultrasound irradiation of fibrinogen have been isolated by gel filtration and studied by disc gel electrophoresis and analytical ultracentrifugation. They show molecular properties similar to those of the fragments obtained by endopeptidase incubation and the protein degradation proceeds in a similar way. All that can be interpreted according to a trinodular model for the fibrinogen molecule, with two elongated fibrous zones more easily cleaved by mechanical forces and less compact parts of the molecule that are mostly constituted by the alpha-chains. |
| Title |
Structure function: theory, ultrasonic measurement, and histology |
| Author |
Han A, O'Brien WD Jr. |
| Journal |
IEEE Int Ultrasonics Symp Proc |
| Volume |
|
| Year |
2015 |
| Abstract |
Ultrasonic scattering is determined by not only the properties of individual scatterers, but also the correlation among scatterer positions. The role of scatterer spatial correlation is significant for dense medium, but has not been
fully understood. The effect of scatterer spatial correlation may be modeled by a structure function (three-dimensional Fourier transform of the scatterer positions) as a frequency-dependent factor in the backscatter coefficient (BSC) expression. To study the structure function, we have performed three steps: 1) we
developed theoretical structure function models that take into account the polydispersity of spherical scatterers; 2) we developed the cell pellet biophantom technique to estimate the structure function from ultrasound backscattered data (11 – 105 MHz); 3) we developed algorithms for estimating the structure function from histology, independent of the acoustic measurements. The acoustically estimated and histologically estimated structure functions show consistent frequency dependency, which demonstrates the correlation between
acoustically estimated structure function and scatterer position distribution observed in histology. Furthermore, fitting the theoretical polydisperse structure function model to the experimental structure functions yielded relatively accurate cell radius estimates (error < 16%). Our results suggest that the structure function is required for accurately modeling the acoustic scattering in dense medium.
Keywords—Structure function; acoustic scattering; dense medium; histology; quantitative ultrasound |
| Title |
Studien uber die Beugung von Licht an Ultraschallwellen. II. (Studies on diffraction of light by ultrasound waves.) Article is in German. |
| Author |
Nomoto VO. |
| Journal |
Proc Physico-Math Soc Jpn 3 |
| Volume |
|
| Year |
1942 |
| Abstract |
No abstract available. |
| Title |
Studies assess the safety of ultrasound. |
| Author |
Lapayowker MS. |
| Journal |
The American College of Radio |
| Volume |
|
| Year |
1982 |
| Abstract |
No abstract available. |
| Title |
Studies of inhomogeneous substances by ultrasonic back-scattering. |
| Author |
Fay B, Brendel K, Ludwig G. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1976 |
| Abstract |
A method is outlined by which ultrasonic back-scattering measurements may reveal information concerning both the scattering and absorption properties of inhomogeneous substances. After a description of the principle of the measuring method, experimental studies of a sample consisting of four layers with different scattering properties are discussed. To carry out measurements on substances, the acoustic properties of which are similar to those of biological tissues, inhomogeneous gelatine gels are investigated. The gels are produced using appropriate ethanol-glycerine mixtures. The inhomogeneities were introduced by adding tiny plastic spheres to the gel. It is shown, that the ultrasonic back-scattering method allows separation of the attenuation into scattering and sbroption as functions of the location. In this way recognition of the inhomogeneities is possible. This fact should be helpful in the field of medical diagnostics. |
| Title |
Studies of the biological effects of ultrasound and of synergism between ultrasound and x-rays. |
| Author |
Clarke PR. |
| Journal |
Thesis(PhD): Univ of London |
| Volume |
|
| Year |
1969 |
| Abstract |
No abstract available. |
| Title |
Studies of the cavitational effects of clinical ultrasound by sonoluminescence: 1. Correlation of sonoluminescence with the standing wave pattern in an acoustic field produced by a therapeutic unit. |
| Author |
Leighton TG, Pickworth MJW, Walton AJ, Dendy PP. |
| Journal |
Phys Med Biol |
| Volume |
|
| Year |
1988 |
| Abstract |
No abstract available. |
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