Melville, New York, April 26, 2000
Does nicotine improve a person's ability to filter out background noise? Have singing whales in Australia experienced their version of the "British invasion"? Can sound waves detect plastic landmines?
These and other questions will be addressed at the 139th Meeting of the Acoustical Society of America (ASA), which will be held at the Westin Peachtree Plaza Hotel from May 30-June 3, 2000 in Atlanta, Georgia. Approximately 650 papers will be presented. The ASA is the largest scientific organization in the United States devoted to acoustics, with over 7000 members.
We encourage you to visit ASA's "ASA Press Room" (http://www.acoustics.org) before and during the meeting. Starting the week of May 8 the site will contain lay-language versions of selected papers at the Atlanta meeting.
Does Nicotine Affect Hearing? Acoustics of Political Conventions Catching Dangerous Leaks The Humpback Whale Equivalent of the British Invasion? Sonic Diagnosis of Glaucoma? Solar-Powered Acoustic Refrigerators The Resonance of the Human Lung Acoustical Landmine Detectors Opening the Blood-Brain Barrier with Sound The Science of Vocal Warm-Ups Delivering Drugs with Imploding Bubbles Crime Clues From Recorded Gunshots A New Way to Deliver Insulin The History of Acoustics Neural Causes of Age-Related Hearing Loss? Improving Acoustics in Classrooms Human Capabilities of Dereverberation Detecting Intoxication in Speech
Nicotine may improve the ability of humans to focus on auditory information and filter out background noise. These are the conclusions of a new, exploratory study on 20 nonsmokers with normal hearing. Although follow-up studies need to be carried out, and the results must be replicated elsewhere, the work supports the possibility of using nicotine in a controlled fashion to relieve some symptoms of brain diseases. Nicotine is one of approximately 4000 components in cigarettes, strongly linked to lung cancer and heart disease, but the role of nicotine itself as a carcinogen is controversial. Many of its effects on the human body have been shown to be harmful, while a few have been reported to be beneficial. In the body, nicotine binds to one kind of receptor for the neurotransmitter acetylcholine, thereby classifying it as a "cholinergic drug." Depending on the dose and the length of exposure to nicotine, its binding with cholinergic receptors in the body can activate several pathways in the central nervous system. Scientists have long realized that some regions of the auditory pathway have a lot of the kind of cholinergic receptors which bind with nicotine. Indeed, previous studies in humans have suggested that nicotine has an effect on the auditory pathway, but most were done with smokers in which potentially complex withdrawal symptoms during the study were hard to separate. In addition, it was difficult to know if effects were due to nicotine or the many other compounds associated with smoking. Now, Ashley Harkrider of the University of Tennessee (865-974-1810, aharkrid@utk.edu) and Craig Champlin of the University of Texas studied the response of 20 normal-hearing nonsmokers who received nicotine through the skin. Attaching electrodes to the scalp, they determined electrical activity at several points in the auditory system in response to sound. These measurements indicated that nicotine in these nonsmokers appeared to affect the transmission of information in the midbrain and cortex. These areas are believed to involve processing of auditory information related to alertness to changes in the environment and also to the screening of sensory input. (Paper 4pPP7)
It's a presidential election year in the US, and that means several things to US television viewers: primaries, televised debates, and political conventions. Political conventions are only rivaled by the stock exchange in their raucous clamor. These events pose a challenge to organizers who want to create acoustically intelligible conditions for both the delegates and the broadcast audience. Discussing his experiences with the 1992 Republican Convention in the Houston Astrodome in Houston, the 1996 Republican National Convention in San Diego, and the plans for the 2000 Republican National Convention in Philadelphia, Texas-based acoustical consultant Jack Randorff (806-829-2176) will discuss how best to manage these unruly sonic environments. (2pAA3)
A new "photoacoustic" technique takes just seconds to detect and pinpoint leaks in sealed containers to within a millimeter, even if the leak is so small that it would take a week for it to fill a thimble. No other technique can locate such tiny leaks so quickly. Many consumer or industrial products such as automobiles, refrigerators, and air conditioners include parts that contain liquids or pressurized gases which in some cases may be combustible or hazardous. In a technique developed at the University of Michigan, Serdar Yonak and David Dowling (drd@engin.umich.edu) fill the part being tested for leaks with a tracer gas. A carbon dioxide laser then scans the sample. When the laser beam passes over the cloud formed by the leaking gas, the beam rapidly heats the gas which then expands and generates a sound pulse. This process of producing sound with light is known as "photoacoustics" and it was discovered by Alexander Graham Bell in the 19th century. However, determining the exact location of the leak can be extremely difficult. To do this, the researchers analyze the photoacoustic sound using a state-of-the-art sonar signal processing technique known as matched field processing (MFP). Detecting these leaks and determining their location is a critical process which the researchers hope will lead to safer and more reliable consumer products, safer industrial workplaces, and a reduction of hazardous gas emissions. (2aPA3)
Researchers in Australia have discovered a surprising whale song phenomenon that differs from anything previously reported. Normally, humpback whales in a particular region collaborate with others in their vicinity to develop songs which evolve slowly over the seasons. Observing humpbacks in east Australia, Michael Noad of the University of Sydney (mnoad@mail.usyd.edu.au) and his colleagues noticed the spontaneous appearance of a brand new song among some of the whales. It completely replaced the original song within two years. During that time, they observed whales in the group to sing either their old song or the new song, but nothing in between. The researchers ultimately realized that the new song originated from a completely distinct region, on the west coast of Australia. Previously, researchers did not think that a song could be introduced from this other region. This finding may revise conventional notions of whale songs. As the authors write, "The rapid rise to dominance of an introduced song indicates that song change is not necessarily evolutionary, gradual, or internally driven." (1pAB3)
Mardi Hastings of Ohio State and her colleagues (hastings.6@osu.edu) are studying a new use of ultrasound which may eventually lead to a safe, noninvasive probe of glaucoma and other eye disorders. In their experiments, ultrasound detected low-frequency motion of the cornea which was induced by sound from a separate loudspeaker. The cornea's oscillations provided information on its stiffness. Increasing pressure in the eyeball, a sign of glaucoma, created changes in the cornea's stiffness which could easily be detected. With further development, such noninvasive assessment of corneal stiffness can potentially be applied to diagnosing and treating glaucoma, and monitoring healing after eye injury and cornea surgery. (2pBB11)
Over the past decade, researchers have introduced various designs for thermoacoustic refrigerators, devices that chill objects by using sound waves and inert gases instead of mechanical parts and chemically reactive fluids. Now, two research groups report on a thermoacoustic refrigerator that is powered by the sun. Jay Adeff and Thomas Hofler of the Naval Postgraduate School (hofler@physics.nps.navy.mil) report on a device fully powered by focused sunlight, which then creates the necessary sound waves to begin refrigeration (2aPA4). David Holmberg and colleagues at the National Taiwan University (david@spring.iam.ntu.edu.tw) have built a type of "hybrid" model that runs on both electricity and solar power. (2aPA5) Although further development is required, such sound-based refrigerators could be used for intriguing applications, such as storing ice and other medical supplies in a cooler while in the desert. On a smaller size scale, Ran Yaron of Advanced Refrigeration Technologies in Colorado and colleagues (303-447-2917) are exploring the use of hot exploding bubbles (such as the ones produced by inkjet printers) as heat-exchanging materials which could conceivably be components in tiny "microrefrigerators" and micropumps (2aPA4).
Human activities now produce a significant amount of low-frequency underwater sounds such as sonar. By far the loudest of these are recently developed sonar systems employed by the Navy and by oceanographers. In continuing efforts to ensure that these sounds are safe for all in the ocean environment, including human divers, Peter Rogers and colleagues at Georgia Tech (peter.rogers@me.gatech.edu) set out to determine the response of the human lung to low-frequency underwater sound below 500 Hertz (Hz). Conducting experiments in a high-pressure chamber with 10 human subjects, the researchers measured a strong, depth-dependent "resonance" that occurred on average, at 39 Hz near the surface and 71 Hz at a seawater depth of 120 feet. This, according to the researchers, appears to be "the fundamental resonance of the lungs." In other words, the lung motion produced by sound is greater at these frequencies than at any others--an effect that is likely to make the lungs most susceptible to damage. However, carefully controlled application of sound at the resonance frequency may, ironically, also have beneficial effects. In an ongoing collaborative effort, researchers at Georgia Tech and Emory University are investigating the potential to exploit these effects for the removal of unwanted material from the lungs of cystic fibrosis patients who suffer from an excess buildup of thick mucus in the lungs. (2pBB2)
An estimated 200 million antipersonnel mines have been manufactured over the past 25 years, and more than 350 types of these mines exist, according to the International Campaign to Ban Landmines, a 16-organization group that shared the 1997 Nobel Peace Prize. Joining other researchers worldwide, many acoustical scientists are working to develop significantly improved landmine detectors, ones that can pinpoint as many of the different designs as possible. Waymond Scott and colleagues at Georgia Tech (waymond.scott@ee.gatech.edu) have developed a new detection system that generates gentle seismic waves in the ground, then measures the resulting vibrations with an acoustic sensor. In laboratory experiments, the Georgia Tech system could easily discern antipersonnel mines from buried clutter such as rocks and sticks (4pPA4). In another promising system, James Sabatier of the University of Mississippi and colleagues (sabatier@olemiss.edu) broadcast sound to the ground, producing telltale vibrations which are then monitored with a laser sensor. Having detected a record 95 percent of all buried mines at a challenging Army field test last year, the researchers are developing their system to detect different types of mines in different soil types and at different burial depths. Such acoustic-based systems offer hope for detecting all types of mines, not just ones that are made of metal. (4pPA1)
A major problem with delivering drugs into the brain is the presence of the "blood-brain barrier" (BBB), the protective barricade that obstructs the passage of material between blood and brain tissue. In new studies, Pierre Mourad and colleagues at the University of Washington (pierre@apl.washington.edu) have shown that high- intensity focused ultrasound can disrupt the BBB in a reversible and controlled manner--and conceivably allow the transfer of drugs--without injuring the surrounding central nervous system. In addition, this effect reverses within 96 hours. High-intensity focused ultrasound can induce normally impermeable dyes from the bloodstream into the brain without damaging the central nervous system. While this work needs further development, it may eventually lay the groundwork for providing a safe, effective way to deliver drugs through the blood-brain barrier. (2aBB9)
The key to a successful vocal performance (or even a rehearsal) is to do the proper warm-ups. Traditionally, soloists or choirs sing a few scales or series of notes on selected vowels. However, greater understanding of the human voice and exercise physiology, have transformed vocal warm-ups into a science. Presenting a system of warm-up exercises that have become part of modern regimens, Ingo Titze of the University of Iowa (ingo-titze@uiowa.edu) will explain how these exercises actively target specific muscles and even regions of the vocal tract (3pMU1). Using real-time voice synthesis techniques, Sten Ternstrom of the Royal Institution of Technology in Stockholm, Sweden (sten@speech.kth.se) will illustrate the differences between solo and choral voices and explore the acoustical nature of the "chorus effect" and the child's singing voice (3pMU3). Seung-Jae Moon of Ajou University in Korea (sjmoon@madang.ajou.ac.kr) will discuss the unique characteristics of the Korean singing voice, called "Pansori"; his work shows that trained singers of this style exhibit preferred vocal frequencies (formants) that differ from those of non-singers, and suggests that this may be due to permanent changes in the vocal cords. (3pMU4)
Evan Unger of the University of Arizona and ImaRx Therapeutics in Tucson (eunger@imarx.com) has developed tiny micron-sized bubbles that carry drugs and genes into cells. Irradiated by ultrasound, these bubbles can implode next to a cell, temporarily disrupting the cell membrane and enabling a desired drug or gene to enter the cell. This technique offers a promising avenue to site-specific drug delivery or gene therapy. Also, the microbubbles can potentially be used for sonothrombolysis, or dissolving blood clots with sound. For traditional applications of therapeutic ultrasound like breaking kidney stones, the microbubbles may also enable use of lower power levels (2aBB1). Hector Guzman of Georgia Tech (hg31@prism.gatech.edu) will also discuss efforts in determining the optimal conditions for using sound to introduce large amounts of molecules into cells (2pBB6). In efforts to monitor these treatments, Mark Prausnitz of Georgia Tech (mark.prausnitz@che.gatech.edu) will describe how the successful introduction of material into cells seems to be linked with sonoluminescence, the emission of light from acoustically imploding bubbles (2pBB5).
In attempts to better reconstruct crime scenes or other incidents involving gunfire, a Federal Bureau of Investigation-US Army-industrial collaboration (including Steven Beck of BAE Systems in Austin, Texas, sbeck@tracor.com) has developed a new method for analyzing recorded gunshots and determining such factors as the kind of weapon that was used. At an outdoor range, the researchers recorded sounds from a variety of weapons, from handguns to military rifles. Using these recorded sounds, they developed a computer model for reproducing the different gunshot sounds in this environment. This computer model could potentially be used to reconstruct crime scenes. In addition, the researchers developed a forensic procedure that can incorporate prior knowledge of the incident into the analysis of the gunshot signals. (2aSP8)
Advances continue in the efforts to use sound waves in place of needles for the treatment of diabetes. Earlier this year, researchers from Israel and the US reported an ultrasound technique that temporarily opens tiny pores in the skin and enables a small sample of glucose molecules to reach the surface, allowing diabetes patients to monitor their blood sugar levels without drawing blood. Researchers have also been developing the reverse technique: using ultrasound to deliver insulin through a patch directly into the skin. However, this technique has been hampered by the fact that the insulin leaks into the skin even without the application of ultrasound. Now, Pierre Mourad and colleagues at the University of Washington (pierre@apl.washington.edu) have developed a drug-carrying polymer with a self-assembling membrane that acts as an effective barrier before and after the application of ultrasound. During and shortly after the application of ultrasound, the self-assembling membrane temporarily disassembles--releasing the drug--and then reassembles. The work, which requires further development, could eventually make ultrasound-based insulin delivery a reality. (2aBB6)
In preparation for ASA's 75th anniversary in 2004, an ongoing lecture series on the history of acoustics specialties will be continued at the Atlanta meeting. Stanley Ehrlich (74670.3527@compuserve.com), an acoustical consultant from Newport, Rhode Island, will recount the history of engineering acoustics, the discipline that deals with instruments and devices for such applications as medical diagnosis and movie sound systems. He will describe some of the first engineering acousticians: Alexander Graham Bell, Thomas Edison, and Benjamin Franklin (generally credited with the first repeatable experiments in this field) (2aEAb1). Recounting the "flowering of architectural acoustics in the 20th century," Ewart Wetherill of Paoletti Associates in San Francisco (paoletti@csi.com) will also discuss how it has set the stage for the advanced building designs that lie ahead in the 21st century (4aAAb1).
Hearing loss with age may be caused by more than physical wear-and-tear on the sensory cells in the inner ear: researchers are acquiring evidence that the brain and central nervous system may gradually decline in its ability to process the auditory information associated with speech. This would make it more difficult for older adults to perceive fast speech, or speech in noisy environments. Session 2aPP is devoted to the possible neural causes of age-related hearing loss. Joseph Walton of the University of Rochester (jwalton@cc.urmc.rochester.edu) found a degraded response to certain aspects of auditory signals in many aged neurons (2aPP5). Presenting findings on age-related changes in the structure and chemistry of the central auditory system, Robert Frisina of the University of Rochester (rdf@q.ent.rochester.edu) will show PET imaging experiments depicting changes in activity of the human brain during the processing of speech in background noise (2aPP7).
Classrooms often have surprisingly poor acoustics, including high levels of reverberation and background noise from such sources as room fans and air-conditioning systems. Session 3aAA addresses the often simple and inexpensive improvements that can be made in a variety of learning spaces, such as university classrooms (3aAA5), schools for children who are hearing-impaired (3aAA2), school concert halls (3aAA4), and multimedia environments (3aAA1). Matthew Golden of Penn State University (golden@sabine.acs.psu.edu ) will present results of an ongoing study on the noise conditions in seven day-care centers (3aAA6). Gary Siebein of the University of Florida (siebein@nervm.nerdc.ufl.edu) will discuss the effects of background noise and room-finish materials on speech intelligibility in classrooms (3aAA2).
Humans can understand speech even in very reverberant areas. Remarkably, we are often completely unconscious of the reverberation if it occurs in a sufficiently small space where echo times are small. Does the human brain remove reverberation, or does it have the ability to understand echo-filled speech? Brad Libbey and Peter Rogers of Georgia Tech (peter.rogers@me.gatech.edu) set out to address this question. First, they conducted experiments investigating how characteristics of simulated reverberation such as room size, absorption of walls, and listener position affect intelligibility. Further experiments address the effects of reverberation time, the use of two ears, and the type of reverberation on neurological speech processing. The authors plan to present new data which sheds some light on the extent of "neurological dereverberation." (2pPPb3)
How well can intoxication be determined from a person's speech? This question has importance in many areas, including the training of law-enforcement officials. Harry Hollien of the University of Florida and colleagues (hollien@ufcc.ufl.edu) carried out a series of experiments in which subjects produced speech when sober and at three highly controlled levels of intoxication. Listeners included university students and professionals. The researchers found that speakers were judged as drunker than they actually were at mild levels of intoxication but the listeners sharply underestimated intoxication levels for severe inebriation. Interestingly, no significant differences in judging ability existed between nonprofessionals and professionals, or between men and women. (5aSC10)
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