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Journal of the Acoustical Society of America

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Jan 2003

Volume 113, Issue 1, pp. 1-660

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Suppression of large intraluminal bubble expansion in shock wave lithotripsy without compromising stone comminution: Refinement of reflector geometry

Yufeng Zhou and Pei Zhong

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 586-597 (2003); (12 pages) | Cited 3 times

Online Publication Date: 08 Jan 2003

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Using the Hamilton model [Hamilton, J. Acoust. Soc. Am. 93, 1256–1266 (1993)], the effects of reflector geometry on the pulse profile and sequence of the shock waves produced by the original and upgraded reflector of an HM-3 lithotripter were evaluated qualitatively. Guided by this analysis, we have refined the geometry of the upgraded reflector to enhance its suppressive effect on intraluminal bubble expansion without compromising stone comminution in shock wave lithotripsy. Using the original HM-3 reflector at 20 kV, rupture of a standard vessel phantom made of cellulose hollow fiber (i.d. = 0.2 mm), in which degassed water seeded with ultrasound contrast agents was circulated, was produced at the lithotripter focus after about 30 shocks. In contrast, using the upgraded reflector at 24 kV no rupture of the vessel phantom could be produced within a 20-mm diameter around the lithotripter focus even after 200 shocks. On the other hand, stone comminution was comparable between the two reflector configurations, although slightly larger fragments were produced by the upgraded reflector. After 2000 shocks, stone comminution efficiency produced by the original HM-3 reflector at 20 kV is 97.15±1.92% (mean±SD), compared to 90.35±1.96% produced by the upgraded reflector at 24 kV (p<0.02). All together, it was found that the upgraded reflector could significantly reduce the propensity for vessel rupture in shock wave lithotripsy while maintaining satisfactory stone comminution. © 2003 Acoustical Society of America.
Show PACS
43.80.Ev Acoustical measurement methods in biological systems and media
43.80.Gx Mechanisms of action of acoustic energy on biological systems: physical processes, sites of action
43.25.Yw Nonlinear acoustics of bubbly liquids

Echolocation signals of wild Atlantic spotted dolphin (Stenella frontalis)

Whitlow W. L. Au and Denise L. Herzing

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 598-604 (2003); (7 pages) | Cited 23 times

Online Publication Date: 08 Jan 2003

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An array of four hydrophones arranged in a symmetrical star configuration was used to measure the echolocation signals of the Atlantic spotted dolphin (Stenella frontalis) in the Bahamas. The spacing between the center hydrophone and the other hydrophones was 45.7 cm. A video camera was attached to the array and a video tape recorder was time synchronized with the computer used to digitize the acoustic signals. The echolocation signals had bi-modal frequency spectra with a low-frequency peak between 40 and 50 kHz and a high-frequency peak between 110 and 130 kHz. The low-frequency peak was dominant when the signal the source level was low and the high-frequency peak dominated when the source level was high. Peak-to-peak source levels as high as 210 dB re 1 μPa were measured. The source level varied in amplitude approximately as a function of the one-way transmission loss for signals traveling from the animals to the array. The characteristics of the signals were similar to those of captive Tursiops truncatus, Delphinapterus leucas and Pseudorca crassidens measured in open waters under controlled conditions. © 2003 Acoustical Society of America.
Show PACS
43.80.Ev Acoustical measurement methods in biological systems and media
43.80.Ka Sound production by animals: mechanisms, characteristics, populations, biosonar
43.80.Jz Use of acoustic energy (with or without other forms) in studies of structure and function of biological systems

Echolocation in the Risso’s dolphin, Grampus griseus

Jennifer D. Philips, Paul E. Nachtigall, Whitlow W. L. Au, Jeffrey L. Pawloski, and Herbert L. Roitblat

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 605-616 (2003); (12 pages) | Cited 5 times

Online Publication Date: 08 Jan 2003

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The Risso’s dolphin (Grampus griseus) is an exclusively cephalopod-consuming delphinid with a distinctive vertical indentation along its forehead. To investigate whether or not the species echolocates, a female Risso’s dolphin was trained to discriminate an aluminum cylinder from a nylon sphere (experiment 1) or an aluminum sphere (experiment 2) while wearing eyecups and free swimming in an open-water pen in Kaneohe Bay, Hawaii. The dolphin completed the task with little difficulty despite being blindfolded. Clicks emitted by the dolphin were acquired at average amplitudes of 192.6 dB re 1 μPa, with estimated sources levels up to 216 dB re 1 μPa-1 m. Clicks were acquired with peak frequencies as high as 104.7 kHz (Mfp = 47.9 kHz), center frequencies as high as 85.7 kHz (Mf0 = 56.5 kHz), 3-dB bandwidths up to 94.1 kHz (MBW = 39.7 kHz), and root-mean-square bandwidths up to 32.8 kHz (MRMS = 23.3 kHz). Click durations were between 40 and 70 μs. The data establish that the Risso’s dolphin echolocates, and that, aside from slightly lower amplitudes and frequencies, the clicks emitted by the dolphin were similar to those emitted by other echolocating odontocetes. The particular acoustic and behavioral findings in the study are discussed with respect to the possible direction of the sonar transmission beam of the species. © 2003 Acoustical Society of America.
Show PACS
43.80.Ka Sound production by animals: mechanisms, characteristics, populations, biosonar
43.80.Jz Use of acoustic energy (with or without other forms) in studies of structure and function of biological systems

The influence of flight speed on the ranging performance of bats using frequency modulated echolocation pulses

Arjan M. Boonman, Stuart Parsons, and Gareth Jones

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 617-628 (2003); (12 pages) | Cited 1 time

Online Publication Date: 08 Jan 2003

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Many species of bat use ultrasonic frequency modulated (FM) pulses to measure the distance to objects by timing the emission and reception of each pulse. Echolocation is mainly used in flight. Since the flight speed of bats often exceeds 1% of the speed of sound, Doppler effects will lead to compression of the time between emission and reception as well as an elevation of the echo frequencies, resulting in a distortion of the perceived range. This paper describes the consequences of these Doppler effects on the ranging performance of bats using different pulse designs. The consequences of Doppler effects on ranging performance described in this paper assume bats to have a very accurate ranging resolution, which is feasible with a filterbank receiver. By modeling two receiver types, it was first established that the effects of Doppler compression are virtually independent of the receiver type. Then, used a cross-correlation model was used to investigate the effect of flight speed on Doppler tolerance and range–Doppler coupling separately. This paper further shows how pulse duration, bandwidth, function type, and harmonics influence Doppler tolerance and range–Doppler coupling. The influence of each signal parameter is illustrated using calls of several bat species. It is argued that range–Doppler coupling is a significant source of error in bat echolocation, and various strategies bats could employ to deal with this problem, including the use of range rate information are discussed. © 2003 Acoustical Society of America.
Show PACS
43.80.Ka Sound production by animals: mechanisms, characteristics, populations, biosonar
43.80.Lb Sound reception by animals: anatomy, physiology, auditory capacities, processing
43.60.Gk Space-time signal processing, other than matched field processing

Measuring hearing in the harbor seal (Phoca vitulina): Comparison of behavioral and auditory brainstem response techniques

Lawrence F. Wolski, Rindy C. Anderson, Ann E. Bowles, and Pamela K. Yochem

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 629-637 (2003); (9 pages) | Cited 11 times

Online Publication Date: 08 Jan 2003

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Auditory brainstem response (ABR) and standard behavioral methods were compared by measuring in-air audiograms for an adult female harbor seal (Phoca vitulina). Behavioral audiograms were obtained using two techniques: the method of constant stimuli and the staircase method. Sensitivity was tested from 0.250 to 30 kHz. The seal showed good sensitivity from 6 to 12 kHz [best sensitivity 8.1 dB (re 20 μPa2⋅s) RMS at 8 kHz]. The staircase method yielded thresholds that were lower by 10 dB on average than the method of constant stimuli. ABRs were recorded at 2, 4, 8, 16, and 22 kHz and showed a similar best range (8–16 kHz). ABR thresholds averaged 5.7 dB higher than behavioral thresholds at 2, 4, and 8 kHz. ABRs were at least 7 dB lower at 16 kHz, and approximately 3 dB higher at 22 kHz. The better sensitivity of ABRs at higher frequencies could have reflected differences in the seal’s behavior during ABR testing and/or bandwidth characteristics of test stimuli. These results agree with comparisons of ABR and behavioral methods performed in other recent studies and indicate that ABR methods represent a good alternative for estimating hearing range and sensitivity in pinnipeds, particularly when time is a critical factor and animals are untrained. © 2003 Acoustical Society of America.
Show PACS
43.80.Lb Sound reception by animals: anatomy, physiology, auditory capacities, processing
43.80.Nd Effects of noise on animals and associated behavior, protective mechanisms

High intensity anthropogenic sound damages fish ears

Robert D. McCauley, Jane Fewtrell, and Arthur N. Popper

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 638-642 (2003); (5 pages) | Cited 13 times

Online Publication Date: 08 Jan 2003

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Marine petroleum exploration involves the repetitive use of high-energy noise sources, air-guns, that produce a short, sharp, low-frequency sound. Despite reports of behavioral responses of fishes and marine mammals to such noise, it is not known whether exposure to air-guns has the potential to damage the ears of aquatic vertebrates. It is shown here that the ears of fish exposed to an operating air-gun sustained extensive damage to their sensory epithelia that was apparent as ablated hair cells. The damage was regionally severe, with no evidence of repair or replacement of damaged sensory cells up to 58 days after air-gun exposure. © 2003 Acoustical Society of America.
Show PACS
43.80.Nd Effects of noise on animals and associated behavior, protective mechanisms
43.64.Wn Effects of noise and trauma on the auditory system

A comparison of the fragmentation thresholds and inertial cavitation doses of different ultrasound contrast agents

Wen-Shiang Chen, Thomas J. Matula, Andrew A. Brayman, and Lawrence A. Crum

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 643-651 (2003); (9 pages) | Cited 13 times

Online Publication Date: 08 Jan 2003

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Contrast bubble destruction is important in several new diagnostic and therapeutic applications. The pressure threshold of destruction is determined by the shell material, while the propensity for of the bubbles to undergo inertial cavitation (IC) depends both on the gas and shell properties of the ultrasound contrast agent (UCA). The ultrasonic fragmentation thresholds of three specific UCAs (Optison, Sonazoid, and biSpheres), each with different shell and gas properties, were determined under various acoustic conditions. The acoustic emissions generated by the agents, or their derivatives, characteristic of IC after fragmentation, was also compared, using cumulated broadband-noise emissions (IC “dose”). Albumin-shelled Optison and surfactant-shelled Sonazoid had low fragmentation thresholds (mean = 0.13 and 0.15 MPa at 1.1 MHz, 0.48 and 0.58 MPa at 3.5 MHz, respectively), while polymer-shelled biSpheres had a significant higher threshold (mean = 0.19 and 0.23 MPa at 1.1 MHz, 0.73 and 0.96 MPa for thin- and thick-shell biSpheres at 3.5 MHz, respectively, p<0.01). At comparable initial concentrations, surfactant-shelled Sonazoid produced a much larger IC dose after shell destruction than did either biSpheres or Optison (p<0.01). Thick-shelled biSpheres had the highest fragmentation threshold and produced the lowest IC dose. More than two and five acoustic cycles, respectively, were necessary for the thin- and thick-shell biSpheres to reach a steady-state fragmentation threshold. © 2003 Acoustical Society of America.
Show PACS
43.80.Qf Medical diagnosis with acoustics
43.25.Yw Nonlinear acoustics of bubbly liquids

Microparticle column geometry in acoustic stationary fields

Andrew Hancock, Michael F. Insana, and John S. Allen

J. Acoust. Soc. Am. Volume 113, Issue 1, pp. 652-659 (2003); (8 pages) | Cited 1 time

Online Publication Date: 08 Jan 2003

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Particles suspended in a fluid will experience forces from stationary acoustic fields. The magnitude of the force depends on the time-averaged energy density of the field and the material properties of the particles and fluid. Forces acting on known particles smaller than 20 μm were studied. Within a 500 kHz acoustic beam generated by a plane-piston circular source, observations were made of the geometry of the particle column that is formed. Varying the acoustic energy altered the column width in a manner predicted by equations for the primary acoustic radiation force from scattering of particles in the long-wavelength limit. The minimum pressures required to trap gas, solid, and liquid particles in a water medium at room temperature were also estimated to within 12%. These results highlight the ability of stationary acoustic fields from a plane-piston radiator to impose nano-Newton-scale forces onto fluid particles with properties similar to biological cells, and suggest that it is possible to accurately quantify these forces. © 2003 Acoustical Society of America.
Show PACS
43.80.Vj Acoustical medical instrumentation and measurement techniques
43.20.Rz Steady-state radiation from sources, impedance, radiation patterns, boundary element methods
43.25.Uv Acoustic levitation
43.25.Qp Radiation pressure
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