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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 85 out of 330
| Title |
Development of a high intensity focused ultrasound (HIFU) hydrophone system. |
| Author |
Schafer ME. |
| Journal |
J. Acoust. Soc. Am |
| Volume |
|
| Year |
2009 |
| Abstract |
No Abstract Available. |
| Title |
Development of a theoretical model describing sonoporation activity of cells exposed to ultrasound in the presence of contrast agents. |
| Author |
Forbes MM, O'Brien WD Jr. |
| Journal |
J Acoust Soc Am |
| Volume |
|
| Year |
2012 |
| Abstract |
Sonoporation uses ultrasound, with the aid of ultrasound contrast agents (UCAs), to enhance cell permeabilization, thereby allowing delivery of therapeutic compounds noninvasively into specific target cells. The objective of this study was to determine if a computational model describing shear stress on a cell membrane due to microstreaming would successfully reflect sonoporation activity
with respect to the peak rarefactional pressure. The theoretical models were compared to the sonoporation results from Chinese hamster ovary cells using DefinityVR at 0.9, 3.15, and 5.6 MHz and were found to accurately describe the maximum sonoporation activity, the pressure where a decrease in sonoporation activity occurs, and relative differences between maximum activity and
the activity after that decrease. Therefore, the model supports the experimental findings that shear stress on cell membranes secondary to oscillating UCAs results in sonoporation. |
| Title |
Development of a thermoelectric sensor for ultrasonic intensity measurement. |
| Author |
Romdhane M, Gourdon C, Casamatta G. |
| Journal |
Ultrasonics |
| Volume |
|
| Year |
1995 |
| Abstract |
The design of ultrasonic reactors lies partly upon the description of the ultrasonic intensity space and time distribution. Among other techniques, the thermoelectric probe seems to be one of the most appropriate tools to measure the intensity available. It consists of a thermocouple embedded in an absorbing material (silicone). The modeling of the heat transfer allows the establishment of the relationship between the temperature signal response of the probe and the ultrasound intensity. It is shown that either the initial rate of temperature rise or the difference between the steady-state probe temperature and the medium temperature can be used. In addition, the measurements show the importance of the height and nature of the liquid sonicated on the ultrasonic intensity distribution. |
| Title |
Development of an ultrasonic method to detect cervical remodeling in vivo in full-term pregnant women |
| Author |
McFarlin BL, Balash J, Kumar V, Bigelow TA, Pombar X, Abramowicz JS, O'Brien WD Jr. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
2015 |
| Abstract |
The objective of this study was to determine whether estimates of ultrasonic attenuation could detect changes in the cervix associated with medically induced cervical remodeling. Thirty-six full-term pregnant women underwent two transvaginal ultrasonic examinations separated in time by 12 h to determine cervical attenuation, cervical length and changes thereof. Ultrasonic attenuation and cervical length data were acquired from a zone (Zonare Medical Systems, Mountain View, CA, USA) ultrasound system using a 5–9 MHz endovaginal probe. Cervical attenuation and cervical length significantly decreased in the 12 h between the pre-cervical ripening time point and 12 h later. The mean cervical attenuation was 1.1 ± 0.4 dB/cm-MHz before cervical ripening agents were used and 0.8 ± 0.4 dB/cm-MHz 12 h later (p , 0.0001). The mean cervical length also decreased from 3.1 ± 0.9 cm before the cervical ripening was administered to 2.0 ± 1.1 cm 12 h later (p, 0.0001). Cervical attenuation and cervical length detected changes in cervical remodeling 12 h after cervical ripening administration. (E-mail: bmcfar1@uic.edu) |
| Title |
Development of localized gene delivery using a dual-intensity ultrasound system in the bladder. |
| Author |
Horie S,Watanabe Y,Chen R,Mori S,Matsumura Y,Kodama T. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
2010 |
| Abstract |
A dual-intensity ultrasound system (DIUS) using nanobubbles offers opportunities for localized gene delivery. This system consists of low-/high-ultrasound intensities. The bladder is a balloon-shaped closed organ in which the behavior of nanobubbles can be controlled spatially and temporally by ultrasound exposure. We hypothesized that when a DIUS with nanobubbles was used, low-intensity ultrasound would direct nanobubbles to targeted cells in the bladder, whereas high-intensity ultrasound intensity would collapse nanobubbles and increase cell membrane permeability, facilitating entry of exogenous molecules into proximate cells. A high-frequency ultrasound imaging system characterized movement and fragmentation of nanobubbles in the bladder. Confocal microscopy revealed that fluorescent molecules were delivered in the localized bladder wall, whereas histochemical examination indicated that the molecular transfer efficiency depended on the acoustic energy. A bioluminescence imaging system showed luciferase plasmid DNA was actually transfected in the bladder wall and subsequent transfection depended on acoustic energy. These findings indicate that delivery of exogenous molecules in the bladder using this approach results in high localization of molecular delivery, facilitating gene therapy for bladder cancer. |
| Title |
Development of methods of precise ultrasonic measurements in small volumes of liquids. |
| Author |
Sarvazyan AP. |
| Journal |
Ultrasonics |
| Volume |
|
| Year |
1982 |
| Abstract |
The application of ultrasonic methods to investigation of problems of molecular physics and molecular biology is greatly limited by the necessity of precise measurements of ultrasound velocity and absorption in small volumes of liquids. Fixed path interferometric methods are the most adequate for such measurements in the low MHz region. In this paper disadvantages of the present interferometric methods of ultrasonic measurements are considered and new resonator cells and a simple device for such measurements are described. Accuracies of 10(exp)-4 % for the velocity change and to better than 1% for the attenuation change, at frequencies of about 7 MHz, are obtained by the device described. The volumes of the resonator cells vary within 0.1 to 0.8 ml depending on the purpose of investigation. |
| Title |
Development of ultrasonic investigations in medicine and biology in the U.S.S.R. |
| Author |
Mayev RG. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1985 |
| Abstract |
Ultrasonic research in biology and medicine, both fundamental and applied, has become so vast in scope, that a mere listing of specific subject-areas would take up too much space. This article is intended to give an overview of Soviet scientists' contribution to the field, with the emphasis on the most important and promising subject-areas which are now given priority in the U.S.S.R. Among specific subject-areas in ultrasonics are the studies of the biological action of ultrasound.and ultrasonic safety in medicine, the effect of focused ultrasound, acoustic spectroscopy of solutions of biological media and acoustic specification of biological objects, acoustic visualization and microscopy and clinical ultrasonics. |
| Title |
Deviations from Rayleigh statistics in ultrasonic speckle. |
| Author |
Tuthill TA, Sperry RH, Parker KJ. |
| Journal |
Ultrason Imaging |
| Volume |
|
| Year |
1988 |
| Abstract |
The statistics of speckle patterns in ultrasound images have potential for tissue characterization. In "fully developed speckle" from many random scatterers, the amplitude is widely recognized as possessing a Rayleigh distribution. This study examines how scattering populations and signal processing can produce non-Rayleigh distributions. The first order speckle statistics are shown to depend on random scatterer density and the amplitude and spacing of added periodic scatterers. Envelope detection, amplifier compression, and signal bandwidth are also shown to cause distinct changes in the signal distribution. |
| Title |
Diagnostic applications of ultrasound in cardiology. |
| Author |
Kossoff G. |
| Journal |
Australas Radiol |
| Volume |
|
| Year |
1966 |
| Abstract |
No abstract available. |
| Title |
Diagnostic insonation of extra utero human placentas: no effect of lymphocytic sister chromatid exchange. |
| Author |
Brulfert A, Ciaravino V, Miller MW, Maulik D, Carstensen EL. |
| Journal |
Hum Genet |
| Volume |
|
| Year |
1984 |
| Abstract |
Freshly delivered human placentas were exposed to ultrasound for 30 min using a diagnostic linear array unit. Blood was then drawn and cultured in the presence of bromodeoxyuridine, and the frequencies of sister chromatid exchanges (SCE) in the lymphocytes determined. There was no statistically significant difference in SCE frequencies between control and exposed cells; the frequencies of SCEs per cell ranged from 4.50 to 6.02 for control and from 4.66 to 6.10 for exposed cells in five separate experiments. Positive control mitomycin C treated cells were significantly affected, with more than 50 SCEs per cell. |
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