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Contents

• New Fellows of the Acoustical Society of America
• F. V. Hunt Postdoctoral Research Fellowship awarded to Erica E. Bowden
• Reports from F. V. Hunt Postdoctoral Fellows
  • Report of the 25th F. V. Hunt Post-Doctoral Fellow (2002–03)
  • Report of the 26th F. V. Hunt Postdoctoral Fellow (2003-04)
  • Report of the 27th F. V. Hunt Postdoctoral Fellow (2004-05)
• USA Meetings Calendar
• Cumulative Indexes to the Journal of the Acoustical Society of America

Carol Espy-WilsonFor contributions to speech communication and mentoring

Lee A. MillerFor elucidating the mechanisms of insect countermeaures to echolocating bats

Shrekanth NarayananFor contributions in speech production and imaging

Simon D. RichardsFor contributions to high frequency acoustics in littoral waters

Gail ter HaarFor contributions to ultrasound safety and standardization

The 2006-07 F. V. Hunt Postdoctoral Research Fellowship in Acoustics has been awarded to Erica E. Bowden. Erica Bowden received a B.S. degree in Architectural Engineering from Kansas State University, Manhattan, KS. She is now enrolled in the University of Nebraska and expects to receive a Ph.D. degree in Architectural Engineering in May 2006. Her Ph.D. thesis is titled "Relating indoor noise criteria systems to human performance and noise perception."During her Hunt Fellowship year, Ms. Bowden will undertake a research program in the Department of Environmental Medicine at the Sahlgrenska Academy at Göteborg University in Göteborg, Sweden. The subject of her research will be "Establishing a hospital soundscape through qualitative and quantitative observation."

The Hunt Fellowship is granted each year to an ASA member who has recently received his or her doctorate or will be receiving the degree in the year in which the fellowship is to be granted. The recipient of the fellowship is that individual who, through personal qualifications and a proposed research topic, is judged to exhibit the highest potential for benefiting any aspect of the science of sound and promoting its usefulness to society. Further information about the fellowship is available from the Acoustical Society of America, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502. Telephone: 516-576-2360; Fax: 516-576-2377. Electronic mail: asa@aip.org; Web: asa.aip.org/fellowships.html

Constantin C. Coussios, Magdalen College, Oxford, OX1 4AU, U.K.

As the 2003-2004 F. V. Hunt Postdoctoral Fellow, I had the privilege of working under the guidance of Professor Ronald A. Roy in the Department of Aerospace and Mechanical Engineering at Boston University. The primary objective of my research was to develop a method for monitoring and controlling cavitation induced by high-intensity focused ultrasound (HIFU) in human tissue.

Real-time detection and monitoring of inertial cavitation are becoming increasingly important in the context of therapeutic ultrasound in general and thermal ablation by high-intensity focused ultrasound (HIFU) in particular. Earlier studies at Boston University and elsewhere had indicated that generating and sustaining inertial cavitation could lead to as much as a fivefold increase in the rate of tissue heating during HIFU exposure. However, once nucleated and excited, cavitating microbubbles tend to grow unstably towards the HIFU transducer, shielding the original focus and causing undesirable thermal damage in the prefocal region. Developing an ability to monitor and detect inertially cavitating microbububbles in real time is therefore key to preventing undesired bioeffects and to controlling the extent of the thermally ablated region. By performing simultaneous cavitation detection in tissue-mimicking materials using both a passive cavitation detector (PCD) and a clinical 5  MHz ultrasound imaging head, it was concluded that the appearance of a hyperechogenic region in B-mode images is neither a necessary nor a sufficient condition for cavitation to have occurred at the HIFU focus. In addition, the PCD system developed enabled real-time monitoring of the microbubble field, as well as of the bubble cloud shift towards the transcranial ultrasound therapy system transducer during prolonged exposure. Excellent agreement was found between the peak-detected PCD value and broadband noise emissions in the frequency-domain, which are indicative of inertial cavitation activity: it was therefore concluded that the developed peak-detected PCD system constitutes a cost-effective yet sensitive means of real-time cavitation detection during HIFU exposure. This work was presented at the 147th meeting of the ASA in New York. It is anticipated that this will form the basis of a feedback control system for inertial cavitation during clinical HIFU application.

Two further research activities took place during my Hunt fellowship year, triggered by the opportunity to build two active cavitation detectors (ACD) pretty much from scratch. The first was used not to detect cavitation, but to determine the effect that the presence of red blood cells have on the acoustic response of stabilized gas bubbles (ultrasound contrast agents—UCAs). This study, conducted in collaboration with Paolo Zanetti, led to the conclusion that high concentrations of red blood cells inhibit the response of UCAs to acoustic excitation. Ultrasound attenuation through UCA suspensions in blood was also found to be dominated by red blood cells at low UCA concentrations, and by the gas bubbles at high UCA concentrations. This work was presented by Paolo Zanetti at the 147th Meeting of the ASA in New York, where he was awarded the Best Student Paper Award in Biomedical Ultrasond/Bioresponse to Vibration. The second ACD was taken to the Department of Biomedical Engineering at the University of Cincinnati where, under the guidance of Professor Christy K. Holland, it was utilized in conjunction with a custom-built PCD to assess the relative role played by inertial and stable cavitation during ultrasound-assisted thrombolysis.

I am extremely grateful to Professor Roy for his selfless mentorship and guidance, and for spending countless hours debating theoretical and experimental aspects of acoustics with me. He repeatedly placed my best interests above his own and was a truly exceptional scientific and career mentor. During my time at Boston University, I also greatly benefited from challenging interactions with Professors Glynn Holt, Robin Cleveland, Paul Barbone, Michael Howe, Allan Pierce, and William Carey, to name but a few. I am also extremely grateful to the exceptional graduate students that I worked with throughout my time in Boston, and in particular to Paolo Zanetti, Caleb Farny, and Charles Thomas: They made invaluable contributions to both the quality and quantity of research carried out during my Hunt Fellowship year. Finally, I would like to thank the Acoustical Society for the most formative and intellectually challenging year of my life to date. Given my research interests, I could not have hoped for a better research environment and better conditions under which to carry out my Hunt fellowship, which ended with my appointment to a joint University Lecturership in Biomedical Engineering and a Magdalen College Tutorial Fellowship at the University of Oxford (UK). This has now become the home of the newly established Biomedical Acoustics Laboratory, in which I hope to perpetuate the excellence in research, acoustics education, and graduate mentoring to which I was exposed at Boston University and through the Acoustical Society.

Tyrone Porter, Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio 45267.

My tenure as the 26th Frederick V. Hunt Fellow was spent under the mentorship of Dr. Christy K. Holland at the University of Cincinnati. Dr. Holland had recently received funding for a joint project with scientists at Northwestern University to develop a Transcranial Ultrasound Therapy System (TUTS) for the treatment of stroke. After injection of targeted liposomes specially formulated to encapsulate air and a clot-busting drug, ultrasound would be used to break the vesicles and release the drug at the site of the clot. Additionally, these echogenic liposomes (ELIP) could be used as targeted ultrasound contrast agents for diagnostic ultrasound imaging of atherosclerotic plaques. The primary goals of my project were: (1) To determine the backscatter and attenuation coefficients for echogenic liposomes as a function of frequency, and (2) to identify the pressure threshold(s) for the destruction of these liposomes and Optison®, a commercially available ultrasound contrast agent.

The backscatter coefficient is a parameter that describes the effectiveness with which a given mass scatters acoustic power. Its magnitude is dependent upon the several factors, including the scattering cross section of the insonated media, and, in the case of ultrasound contrast agents, the viscoelastic properties of the outer shell. Therefore, it is possible to calculate the mean volume of gas trapped inside a single liposome. Additionally, the evaluation of the backscatter and attenuation coefficients as a function of frequency provides information on the resonant behavior of the encapsulated microbubbles. This information can be used to guide the selection of acoustic parameters to optimize contrast enhancement in ultrasound images.

I spent the first part of my fellowship learning the measurement and data reduction techniques developed by several research groups over the past twenty years for determining the backscatter coefficient. After spending considerable time carefully characterizing the acoustic output of several transducers for the study, I collected backscatter data at 3.5, 7.5, 10.0, and 15.0  MHz. Using the experimentally derived backscatter coefficients, I was able to theoretically determine the shell properties of the liposomes with the help of Dr. Constantin-C. Coussios, the 25th recipient of the Frederick V. Hunt Fellowship. This work was presented at the 147th meeting of ASA in New York, and a manuscript is currently being drafted for submission to JASA

I began work on the destruction thresholds of ELIP at various frequencies toward the end of my fellowship year. Reviewing the literature, I learned that there are several mechanisms for ultrasound contrast agent (UCA) destruction. Since then, I have worked with two graduate students, Denise Smith and Saurabh Datta, on designing data collection and processing techniques for distinguishing between acoustically driven diffusion and fragmentation. Using a laboratory assembled pulse-echo system and a clinical diagnostic ultrasound scanner, Denise and I investigated the behavior of Optison at varying incident pressures. Plotting the backscattered intensity and mean grey-scale values from a region of interest in the B-mode images as a function of time, we identified the pressure threshold for acoustically driven diffusion of Optison® at 3.5  MHz. The measurement and processing techniques and initial results were presented at the 149th meeting of ASA in Vancouver, British Columbia, and a manuscript is in preparation for journal submission.

My year as the Hunt Fellow was fulfilling both scientifically and professionally. Based upon my work during that year, I submitted for and was awarded an NIH supplemental grant. I had the opportunity to gain valuable teaching experience by managing a graduate level course in the Department of Biomedical Engineering. Dr. Holland has been an amazing mentor, and we have developed a professional relationship that I am sure will continue throughout my career. I would like to thank Dr. George Shaw, Dr. Jason Chang, Dr. Lou McAdory, and our collaborators at Northwestern University for stimulating conversation on the various chemical, biological, and medical aspects of liposomes, stroke, and cardiovascular disease. Finally, I would like to thank the Hunt family and the Acoustical Society of America for providing funding and the support as I begin my post-graduate career.

The following is a list of presentations resulting in part from my year as Hunt Fellow:

Porter, T. M., Smith, D. A. B., and Holland, C. K. "Quantification of the pressure threshold for Optison® destruction," (Accepted for oral presentation at the American Institute of Ultrasound in Medicine Annual Convention, March 24, 2006).

Porter, T. M., Vaidya, S. S., Holland, C. K., Huang, S. L., MacDonald, R. C., and McPherson, D. D. (2005) "Evaluation of backscattered intensity to quantify the destruction rate of echogenic liposomes," 149th Meeting of The Acoustical Society of America joint meeting with the Canadian Acoustical Association, Vancouver, British Columbia, May 16–20.

Porter, T. M., Holland, C. K., Huang, S., McDonald, R. C., and McPherson, D. D. (2004) "In vitro characterization of echogenic liposomes by acoustic scattering at 3.5–15.0  MHz," 147th Meeting of The Acoustical Society of America, New York, NY, May 24–28.

Xuedong Zhang, Auditory Perception Group, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.

Although it is widely accepted that the responses to sounds in the high-frequency, basal, end of the cochlea are highly nonlinear and sharply tuned, our knowledge of how the cochlea responds to sounds in the low-frequency apical region is sparse and highly controversial due to the technical difficulties of measuring directly from the apex of the mammalian cochlea. As the 2004-2005 F. V. Hunt Postodctoral Fellow, I worked with Dr. Andrew J. Oxenham at the Massachusetts Institute of Technology to study human cochlear mechanics in the low-frequency region, by combining behavioral and quantitative modeling techniques. The specific goal of the research is to estimate the human cochlear tuning at low frequencies using both nonsimultaneous (forward) and simultaneous masking techniques, and to explore whether any differences in the estimates can attribute to the nonlinear interactions between the masker and signal within the cochlea.

In the behavioral study, auditory filter shapes were estimated by measuring signal threshold in the presence of a noise masker with a spectral notch centered around the signal. Twelve normal-hearing subjects participated. The results show that forward masking provides sharper auditory filter estimates than simultaneous masking for all low frequencies tested (250, 500, and 1000  Hz). The filter bandwidth ratios of simultaneous and forward masking are between 1.5 and 2 for all three frequencies, which is comparable with the data from previous studies at higher frequencies. This suggests that, contrary to expectations, nonlinear processing in the low-frequency region of the cochlea may be similar to that found in higher-frequency regions.

Computational modeling was used to simulate the psychophysical results for both forward and simultaneous masking, using the same parameters and tracking procedure as in the behavioral studies. Auditory models with different cochlear nonlinearities were tested in the simulations. The simulation results suggest that suppression could be used to explain the difference of auditory filter estimates between forward and simultaneous masking. The results therefore provide strong constraints on models of cochlear processing and should help in the development of functional models that are valid at all audio frequencies.

Results from our work have been presented in two conferences [Zhang, X., and Oxenham, A. J., "Estimates of auditory filter shapes at low frequencies using forward and simultaneous masking," 28th Annual MidWinter Research Meeting of ARO, (2005); Zhang, X., and Oxenham, A. J., "Modeling study of the influence of the cochlear nonlinearity on psychophysical tuning," 149th Meeting Acoustical Society of America (2005)]. A paper with more recent findings is in preparation and should be submitted by the end of the year.

During my tenure as a Hunt Fellow, I was able to learn the behavior techniques used in hearing studies and to collaborate with distinguished scientist Dr. Oxenham. I am most grateful to the Hunt family and the Acoustical Society for this opportunity.

Editor's note: Please note that the spelling error of the name "Klepper" in "Acoustic analysis in Mudejar-Gothic churches: Experimental results" by Miguel Galindo, Teófilo ZamarreZo, and Sara Girón [J. Acoust. Soc. Am. 117(5), 2783–2888 (2005)] on page 2873 in the fourth paragraph of the Introduction section has been corrected in the online version of JASA. The same misspelling has been corrected in the reference number six within that paper.

Listed below is a summary of meetings related to acoustics to be held in the U.S. in the near future. The month/year notation refers to the issue in which a complete meeting announcement appeared.

	2006
5–9 June	151st Meeting of the Acoustical Society of America, Providence Rhode Island [Acoustical Society of America, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502; Tel.: 516-576-2360; Fax: 516-576-2377; Email: asa@aip.org; Web: http://asa.aip.org].
17–21 Sept.	INTERSPEECH 2006 (ICSLP 2006), Pittsburgh, PA [www.interspeech2006.org]
28 Nov.–2 Dec.	152nd Meeting of the Acoustical Society of America joint with theAcoustical Society of Japan, Honolulu, Hawaii [Acoustical Society of America, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502; Tel.: 516-576-2360; Fax: 516-576-2377; Email: asa@aip.org; Web: http://asa.aip.org]. Deadline for receipt of abstracts: 30 June 2006.
2007
4–8 June	153rd Meeting of the Acoustical Society of America, Salt Lake City, Utah [Acoustical Society of America, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502; Tel.: 516-576-2360; Fax: 516-576-2377; Email: asa@aip.org; Web: http://asa.aip.org].
27 Nov.–2 Dec.	154th Meeting of the Acoustical Society of America, New Orleans, Louisiana (note Tuesday through Saturday) [Acoustical Society of America, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502; Tel.: 516-576-2360; Fax: 516-576-2377; Email: asa@aip.org; Web: http://asa.aip.org].
2008
28 July–1 Aug.	9th International Congress on Noise as a Public Health Problem (Quintennial meeting of ICBEN, the International Commission onBiological Effects of Noise). Foxwoods Resort, Mashantucket, CT [Jerry V. Tobias, ICBEN 9, Post Office Box 1609, Groton CT 06340-1609, Tel. 860-572-0680; Web: www.icben.org. Email icben2008@att.net.

Ordering information: Orders must be paid by check or money order in U.S. funds drawn on a U.S. bank or by Mastercard, Visa, or American Express credit cards. Send orders to Circulation and Fulfillment Division, American Institute of Physics, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502; Tel.: 516-576-2270. Non-U.S. orders add $11 per index.

Some indexes are out of print as noted below.

Volumes 1–10, 1929–1938: JASA, and Contemporary Literature, 1937–1939. Classified by subject and indexed by author. Pp. 131. Price: ASA members $5; Nonmembers $10.

Volumes 11–20, 1939–1948: JASA, Contemporary Literature and Patents. Classified by subject and indexed by author and inventor. Pp. 395. Out of Print.

Volumes 21–30, 1949–1958: JASA, Contemporary Literature and Patents. Classified by subject and indexed by author and inventor. Pp. 952. Price: ASA members $20; Nonmembers $75.

Volumes 31–35, 1959–1963: JASA, Contemporary Literature and Patents. Classified by subject and indexed by author and inventor. Pp. 1140. Price: ASA members $20; Nonmembers $90.

Volumes 36–44, 1964–1968: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 485. Out of Print.

Volumes 36–44, 1964–1968: Contemporary Literature. Classified by subject and indexed by author. Pp. 1060. Out of Print.

Volumes 45–54, 1969–1973: JASA and Patents. Classified by subject and indexed by author and inventor Pp. 540. Price: $20 (paperbound); ASA members $25 (clothbound); Nonmembers $60 (clothbound).

Volumes 55–64, 1974–1978: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 816. Price: $20 (paperbound); ASA members $25 (clothbound); Nonmembers $60 (clothbound).

Volumes 65–74, 1979–1983: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 624. Price: ASA members $25 (paperbound); Nonmembers $75 (clothbound).

Volumes 75–84, 1984–1988: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 625. Price: ASA members $30 (paperbound); Nonmembers $80 (clothbound).

Volumes 85–94, 1989–1993: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 736. Price: ASA members $30 (paperbound); Nonmembers $80 (clothbound).

Volumes 95–104, 1994–1998: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 632, Price: ASA members $40 (paperbound); Nonmembers $90 (clothbound).

Volumes 105–114, 1999–2003: JASA and Patents. Classified by subject and indexed by author and inventor. Pp. 616, Price: ASA members $50; Nonmembers $90 (paperbound).

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