Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [142]-144).

An experimental investigation of the velocity of sound in liquid helium at temperatures near 1° K was abandoned (at an early stage)^when the results of Whitney and Chase(16) became available. The original investigation, which had been motivated by the idea that the peak in the attenuation-temperature curve near 1° K is related to a corresponding feature in the velocity-temperature curve, evolved into a search for mathematical relations connecting the temperature variations of velocity and attenuation. Classical dispersion theory is reviewed, with emphasis on its physical and mathematical foundations. Applications of the theory in the fields of electrical network design, dielectric dispersion and ultrasonics are described in order to illustrate the use and the limitations of the Kramers-Kronig relations. The possibility of extending the scope of the Kramers-Kronig relations, by using variables other than frequency, is discussed. A brief sketch of the quantum mechanical basis of linear response theory is given in support of a proposal to use reciprocal temperature as a variable in dispersion-type relations. An attempt was made to apply dispersion relations in reciprocal temperature to the problem of ultrasonic propagation in liquid helium and a comparison of the predicted and the experimentally observed attenuations at the λ point was found to give encouraging results. The interferometer, to have been used in the proposed experiment is described. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Thesis (M.Sc.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 77-78.

Sonoporation, referring to transient membrane permeation phenomenon generated by acoustic cavitation, has spurred significant scientific interests for its potential applications in facilitating uptake of drugs and genes into living cells. With an increasing level of technical maturity in realizing sonoporation, scientists are trying to gain a deeper understanding of the cellular responses related to this biophysical phenomenon from the standpoint for drug/gene delivery. However, challenges and difficulties remain to be overcome including providing direct evidences for the microbubble-cell wave matter interaction mechanism, obtaining controllable sonoporation at the desired locations on the cell membrane, maintaining the viability of the sonoporated cells with high efficiency delivery outcomes and so on. Such a lack of scientific foundations has been recognized as a fundamental obstacle in substantiating the application merit of sonoporation. In this study, the overall objective is to stepwise unravel the cellular stress induced by microbubble-mediated sonoporation after resealing. To achieve it, two kinds of well-calibrated ultrasound exposure platforms are designed. One of them can be used for the in situ observation of the wave matter interaction ways during sonoporation via the confocal microscope. The other ultrasound exposure setup can be used for the studies of the sonoporation induced bio-effects which need many cells for analysis. With these designed and well calibrated ultrasound exposure platforms, new insights for the cellular impacts induced by sonoporation are provided. As demonstrated in vitro, sonoporation may inadvertently induce repressive cellular features even whilst enhancing exogenous molecule uptake. Both suspension-type (HL-60) and adherence-type (ZR-75-30) cells were employed in this investigation. They were routinely exposed to 1 MHz pulsed ultrasound with calibrated acoustic field profile and in the presence of microbubbles. The post-exposure morphology and the intracellular actin cytoskeletons dynamics of sonoporated cells were examined in situ using confocal microscopy. Furthermore, the cell-cycle progression kinetics of the viable sonoporated cells were analyzed using flow cytometer. Results show that, for both investigated cell types, viable sonoporated cells would exhibit membrane and nucleus shrinkage, intracellular lipid accumulation and actin deploymerization over a two hours period. On the other hand, as compared to the sham control cells, the deoxyribonucleic acid (DNA) synthesis duration of sonoporated cells is significantly lengthened as indicative of a delay in cell-cycle progression. These features are known to be characteristics of a cellular stress response, suggesting that sonoporation indeed constitutes itself as a cellular stress to living cells even after the cells are resealed. In terms of the implication of this work, this study has shown that sonoporation can be a significant cellular stress both short term and long term after ultrasound exposure. In particular, the intracellular homeostasisis found disrupted even with membrane resealing. Therefore, if sonoporation is to be used for drug delivery, efficiency may be a problem that really needs to be solved in optimizing sonoporation for drug/gene delivery purposes. On the other hand, it raises opportunities for developing other therapeutic applications via sonoporation. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Therapeutic ultrasound employs the acoustic energy carried by high-frequency mechanical wave to induce beneficial effects on living systems. This therapeutic approach is advantageous in that its energy could be remotely focused on the targeted tissue in a non-invasive manner. Although ultrasound therapy has been shown to be feasible and effective in both laboratory experiments and clinical trials, its safety and efficacy are still challenged by the lack of fundamental knowledge of how ultrasound wave exerts physical effects on the cell system and how the cell functionally responds to the ultrasound stimulation. Motivated by the above insight, this thesis aims to provide direct experimental evidence for illustrating the biophysical details of how ultrasound wave (alone or combined with microbubble) interacts with live cells. An acoustic experimental platform with well-calibrated ultrasound field and live-cell imaging modality was developed to observe ultrasound-cell interaction. Based on this platform, a series of single-cell studies was then conducted to monitor the structural and functional changes of the live cell as well as its fluorescently-labelled components over the course of ultrasound exposure. Results obtained in this thesis provided image-level evidence for characterizing the ultrasound-cell interactions in the following three aspects. First, it was found that low-intensity ultrasound pulsing could directly perturb the plasma membrane, the cytoskeletal network and the inner nucleus of live neuroblastoma cells. This cytomechanical perturbation would result in reversible and structural alternations of subcellular components. Second, low-intensity pulsed ultrasound, when applied on neuronal cells, could exert morphological impact through inducing neurite retraction and cell body displacement, and electrophysiological impact in the form of membrane depolarization and calcium influx. This finding verified the potential of ultrasound in modulating neuronal development and excitability. Last, the cell membrane perforation and resealing dynamics induced by the ultrasound-activated microbubble were visualized and characterized. The subsequent cellular responses to this ultrasound-induced sonoporation were also identified at both membrane and cytoskeleton levels. The significance of this study is to provide direct and solid experimental evidence for understanding the biophysical interactions between ultrasound wave and live cell. This advanced scientific interpretation is definitely crucial for establishing the cellular mechanisms of therapeutic ultrasound and for providing technical insights into ultrasound treatment. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Laurence J. Jacobs; Committee Member: Jianmin Qu; Committee Member: Jin-Yeon Kim. Part of the SMARTech Electronic Thesis and Dissertation Collection.

No description available.

No description available.

Dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Chiropractic, Technikon Natal, Durban, 1998. / The aim of this study was to determine the effectiveness of adjustments versus the use of ultrasound in the treatment of mechanical neck pain. It was hypothesized that treatment with adjustments over a four week period, with a further four week follow-up period, would be more effective than ultrasound in terms of improving patients' cervical ranges of motion and their perceptions of pain and disability. Thirty consecutive patients suffering from mechanical neck pain were randomly assigned to either the adjustment or ultrasound groups. An experimental design was employed, whereby both groups received treatment twice a week for four weeks. After a follow-up period of a month, the patients were re-assessed. Measurements of the cervical spine ranges of motion with the CROM goniometer, algometer readings, and the completion of the Numerical Pain Rating Scale-101, CMCC Neck Disability Index and the Short Form McGill Pain questionnaires were performed before the first, fourth and final treatments as well as at the one month follow-up consultation. The data were then transferred to spreadsheets and underwent statistical analyses, using a 95 % confidence level. Analyses within each group were performed, using the Wilcoxon Signed Rank test and various readings were compared. The reading taken before the first treatment was compared to the reading taken before the final treatment. The initial reading was then again compared with the reading taken at the one month follow-up consultation. Comparison of the results of both treatment groups was statistically evaluated, using the Mann-Whitney U-Test. The comparison was made using the readings of the first, fourth and final treatments, as well as the one month follow-up consultation. This was done for all measurement parameters. / M