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325 results on '"Crum, L. A."'

1. Comments on 'Evidence for Nuclear Emissions During Acoustic Cavitation' by R.P. Taleyarkhan et al., Science volume 295,p.1868, March 8, 2002

Author

Putterman, S. J., Crum, L. A., and Suslick, K.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

In a paper recently published in Science, Taleyarkhan et al. claimed to observe fusion from acoustic cavitation and the associated phenomenon of sonoluminescence. Although, this is a worthwhile line of investigation we explain why, in our opinion, their data neither proves nor disproves this possibility., Comment: 3 pages

Published
2002

2. Understanding the impacts of anthropogenic sound on beaked whales

Author

Cox, T. M., primary, Ragen, T. J., additional, Read, A. J., additional, Vos, E., additional, Baird, R. W., additional, Balcomb, K., additional, Barlow, J., additional, Caldwell, J., additional, Cranford, T., additional, Crum, L., additional, D'Amico, A., additional, D'Spain, G., additional, Fernandez, A., additional, Finneran, J., additional, Gentry, R., additional, Gerth, W., additional, Gulland, F., additional, Hildebrand, J., additional, Houser, D., additional, Hullar, T., additional, Jepson, P. D., additional, Ketten, D., additional, MacLeod, C. D., additional, Miller, P., additional, Moore, S., additional, Mountain, D. C., additional, Palka, D., additional, Ponganis, P., additional, Rommel, S., additional, Rowles, T., additional, Taylor, B., additional, Tyack, P., additional, Wartzok, D., additional, Gisiner, R., additional, Mead, J., additional, and Benner, L., additional

Published
2023
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11. Therapeutic ultrasound: a promising future in clinical medicine

Author

Crum, L, Bailey, M, Kaczkowski, P, Makin, I, Mourad, P, Beach, K, Carter, S, Schmiedl, U, Chandler, W, Martin, R, Vaezy, S, Keilman, G, Cleveland, R, and Roy, R

Abstract

Although diagnostic ultrasound is now a multi-billion dollar a year industry, the therapeutic applications of ultrasound were initially thought to have more promise. Indeed, the Fry brothers were performing brain surgery on human patients in the early 1950’s, and with considerable success [1]. However, therapeutic ultrasound has still not yet gained its promising potential. Recently, there has been an enormous resurgence of interest in this topic, and several major projects are underway at various facilities around the world. We shall review our own substantial efforts in this area, with brief discussions of topics in lithotripsy, ultrasound-enhanced drug delivery, and acoustic hemostasis.

Published
2019

12. Low-frequency scattering from resonant bubble clouds

Author

Roy, R, Carey, W, Nicholas, M, and Crum, L

Abstract

Preliminary results are presented from a recent experiment carried out at the NUWC Seneca Lake test facility and designed to investigate the scattering properties of bubble clouds produced in fresh water in the absence of boundaries and under known propagation conditions. The test range consisted of both conventional and parametric sources, conventional receivers, and a transient bubbler that was submerged to 91 m. The cloud possessed an elongated teardrop shape (length≊1.4 m, diameter≊0.5 m) with a void fraction of 0.25% and a mean bubble radius of 1.5 mm, which corresponds to a single‐bubble resonance frequency of 6.6 kHz at depth. Backscatter target strengths were measured for frequencies ranging from 300 Hz to 14 kHz. These measurements revealed high target strengths (up to +1 dB) and distinctive peaks in the spectrum at 450 Hz, and 1.3, 3.0, 6.5, and 11 kHz. The low‐frequency results are consistent with calculations (based on the theory of collective bubble oscillations) of the resonance frequency and target strength of a comparably sized, spherical bubble cloud. Certain features of the high‐frequency backscatter data are consistent with single‐bubble resonance scattering. These preliminary results are consistent with the notion that, at low frequencies, the scattering characteristics of a bubble cloud are determined, not by the bubble sizes and number density, but rather by the free‐gas volume fraction and the length scales of the cloud proper.

Published
2019

18. Lack of the receptor for advanced glycation end-products attenuates e. coli pneumonia in mice

Author

Ramsgaard, L, Englert, JM, Manni, ML, Milutinovic, PS, Gefter, J, Tobolewski, J, Crum, L, Coudriet, GM, Piganelli, J, Zamora, R, Vodovotz, Y, Enghild, JJ, Oury, TD, Ramsgaard, L, Englert, JM, Manni, ML, Milutinovic, PS, Gefter, J, Tobolewski, J, Crum, L, Coudriet, GM, Piganelli, J, Zamora, R, Vodovotz, Y, Enghild, JJ, and Oury, TD

Abstract

Background: The receptor for advanced glycation end-products (RAGE) has been suggested to modulate lung injury in models of acute pulmonary inflammation. To study this further, model systems utilizing wild type and RAGE knockout (KO) mice were used to determine the role of RAGE signaling in lipopolysaccharide (LPS) and E. coli induced acute pulmonary inflammation. The effect of intraperitoneal (i.p.) and intratracheal (i.t.) administration of mouse soluble RAGE on E. coli injury was also investigated. Methodology/Principal Findings: C57BL/6 wild type and RAGE KO mice received an i.t. instillation of LPS, E. coli, or vehicle control. Some groups also received i.p. or i.t. administration of mouse soluble RAGE. After 24 hours, the role of RAGE expression on inflammation was assessed by comparing responses in wild type and RAGE KO. RAGE protein levels decreased in wild type lung homogenates after treatment with either LPS or bacteria. In addition, soluble RAGE and HMGB1 increased in the BALF after E. coli instillation. RAGE KO mice challenged with LPS had the same degree of inflammation as wild type mice. However, when challenged with E. coli, RAGE KO mice had significantly less inflammation when compared to wild type mice. Most cytokine levels were lower in the BALF of RAGE KO mice compared to wild type mice after E. coli injury, while only monocyte chemotactic protein-1, MCP-1, was lower after LPS challenge. Neither i.p. nor i.t. administration of mouse soluble RAGE attenuated the severity of E. coli injury in wild type mice. Conclusions/Significance: Lack of RAGE in the lung does not protect against LPS induced acute pulmonary inflammation, but attenuates injury following live E. coli challenge. These findings suggest that RAGE mediates responses to E. coli-associated pathogen-associated molecular pattern molecules other than LPS or other bacterial specific signaling responses. Soluble RAGE treatment had no effect on inflammation. © 2011 Ramsgaard et al.

Published
2011

19. Understanding the Impacts of Anthropogenic Sound on Beaked Whales

Author

SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA, Cox, T M, Ragen, T J, Read, A J, Vos, E, Baird, R W, Balcomb, K, Barlow, J, Caldwell, J, Cranford, T, Crum, L, SPACE AND NAVAL WARFARE SYSTEMS CENTER SAN DIEGO CA, Cox, T M, Ragen, T J, Read, A J, Vos, E, Baird, R W, Balcomb, K, Barlow, J, Caldwell, J, Cranford, T, and Crum, L

Abstract

This review considers the effect of anthropogenic sound on beaked whales. Two major conclusions are presented: (1) gas-bubble disease induced in supersaturated tissue by a behavioural response to acoustic exposure, is a plausible pathologic mechanism for the morbidity and mortality seen in cetaceans associated with sonar exposure and merits further investigation; and (2) current monitoring and mitigation methods for beaked whales are ineffective for detecting these animals and protecting them from adverse sound exposure. In addition, four major research priorities, needed to address information gaps on the impacts of sound on beaked whales, are identified: (1) controlled exposure experiments to assess beaked whale responses to known sound stimuli; (2) investigation of physiology, anatomy, pathobiology and behaviour of beaked whales; (3) assessment of baseline diving behaviour and physiology of beaked whales; and (4) a retrospective review of beaked whale strandings., Published in the Journal of Cetacean Research and Management, v7 n3 p177-187, 2006. Prepared in collaboration with the Southwest Fisheries Science Center, National Marine Fisheries Service, La Jolla, CA, the Office of Protected Resources, National Marine Fisheries Service, Silver Spring, MD, the Navy Experimental Diving Unit, Panama City, FL, the Northeast Fisheries Science Center, National Marine Fisheries Service, Woods Hole, MA, the Office of Naval Research, Alexandria, VA, the National Museum of Natural History, Washington, D.C., and the US Commission on Ocean Policy, Washington, D.C. Sponsored in part by the US Marine Mammal Commission.

Published
2006

25. 2074

Author

Vaezy, S, primary, Zderic, V, additional, Starr, F, additional, Luo, W, additional, Foley, J, additional, and Crum, L, additional

Published
2006
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27. The role of cavitation in therapeutic ultrasound

Author

Crum, L., primary, Bailey, M., additional, Khokhlova, V., additional, Sapozhnikov, O., additional, Rabkin, B., additional, Evan, A., additional, McAteer, J., additional, Pishchalnikov, Y., additional, Williams, J., additional, and Cleveland, R., additional

Published
2006
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34. Po-topic IV-09

Author

Vaezy∗, S., primary, Martin, R., additional, Carter, S., additional, and Crum, L., additional

Published
2003
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38. Acoustic hemostasis

Author

Crum, L., primary, Andrew, M., additional, Bailey, M., additional, Beach, K., additional, Brayman, A., additional, Curra, F., additional, Kaczkowski, P., additional, Kargl, S., additional, Martin, R., additional, and Vaezy, S., additional

Published
2003
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39. Nonlinear Mechanisms of Lesion Formation by High Intensity Focused Ultrasound.

Author

Khokhlova, V. A., Bailey, M. R., Reed, J., Canney, M. S., Kaczkowski, P. J., and Crum, L. A.

Subjects
NONLINEAR mechanics, ANALYTICAL mechanics, POLYACRYLAMIDE, POLYMERS, CAVITATION, HYDRODYNAMICS, PHYSICS
Abstract

Nonlinear mechanisms of lesion formation by high intensity focused ultrasound (HIFU) were investigated experimentally and numerically in a transparent polyacrylamide gel phantom. Numerical predictions were made with a finite-amplitude acoustic propagation model. A 2-MHz transducer of 42-mm diameter and 44.5-mm radius of curvature was operated above the cavitation threshold of the gel phantom at various peak acoustic powers and duty cycles. Acoustic waveforms were recorded in the gel by a fiber optic hydrophone. Bubble activity was detected actively by B-mode diagnostic imaging, passively by a remote focused hydrophone, and optically by CCD and high-speed cameras. Elevated static pressure was applied to suppress bubble activity and increase the boiling temperature, thus isolating the pure effect of acoustic nonlinearity. In overpressure experiment performed at 32 W acoustic power, both cavitation and nonlinear ultrasound propagation accelerated lesion inception and growth, but acoustic nonlinearity, which led to shock formation, played the dominant role. Rapid localized heating, particularly by increased absorption in the shocked wave, led to boiling and then to proximal growth and migration of the lesion even at low overpressure. At 90W acoustic power, boiling was observed and predicted in less than 50 ms. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2006
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41. Effect of selective absorption on nonlinear interactions in high intensity acoustic beams.

Author

Khokhlova, V. A., Kashcheeva, S. S., Averkiou, M. A., and Crum, L. A.

Subjects
ACOUSTIC surface waves, NONLINEAR acoustics
Abstract

The effect of second harmonic selective absorption on nonlinear interactions in high intensity acoustic beams is studied. Diffraction and focusing phenomena are taken into account in addition to nonlinearity and selective absorption. The results are compared with those obtained for one-dimensional plane waves in a selective absorption medium and for the focused beams in a medium without absorption. It is shown that selective absorption of the second harmonic does not prevent shock formation, but results in specific waveform distortion, less asymmetry of the waveform in case of the beam, less amplitude of the shock and corresponding nonlinear attenuation. [ABSTRACT FROM AUTHOR]

Published
2000

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