University News

U. T. Dallas-Led Research Team Produces Strong, Transparent Carbon Nanotube Sheets

University of Texas at Dallas (UTD) nanotechnologists and an Australian colleague have produced transparent carbon nanotube sheets that are stronger than the same-weight steel sheets and have demonstrated applicability for organic light-emitting displays, low-noise electronic sensors, artificial muscles, conducting appliqués and broad-band polarized light sources that can be switched in one ten-thousandths of a second.

Carbon nanotubes are like minute bits of string, and untold trillions of these invisible strings must be assembled to make useful macroscopic articles that can exploit the phenomenal mechanical and electronic properties of the individual nanotubes. In the Aug. 19 issue of the prestigious journal Science, scientists from the NanoTech Institute at UTD and a collaborator, Dr. Ken Atkinson from Commonwealth Scientific and Industrial Research Organization (CSIRO), a national laboratory in Australia, report such assembly of nanotubes into sheets at commercially useable rates.

Starting from chemically grown, self-assembled structures in which nanotubes are aligned like trees in a forest, the sheets are produced at up to seven meters per minute by the coordinated rotation of a trillion nanotubes per minute for every centimeter of sheet width. By comparison, the production rate for commercial wool spinning is 20 meters per minute. Unlike previous sheet fabrication methods using dispersions of nanotubes in liquids, which are quite slow, the dry-state process developed by the UTD-CSIRO team can use the ultra-long nanotubes needed for optimization of properties.

Strength normalized to weight is important for many applications, especially in space and aerospace, and this property of the nanotube sheets already exceeds that of the strongest steel sheets and the Mylar and Kapton sheets used for ultralight air vehicles and proposed for solar sails for space applications, according to the researchers. The nanotube sheets can be made so thin that a square kilometer of solar sail would weigh only 30 kilograms. While sheets normally have much lower strength than fibers or yarns, the strength of the nanotube sheets in the nanotube alignment direction already approaches the highest reported values for polymer-free nanotube yarns.

The nanotube sheets combine high transparency with high electronic conductivity, are highly flexible and provide giant gravimetric surface areas, which has enabled the team to demonstrate their use as electrodes for bright organic light emitting diodes for displays and as solar cells for light harvesting. Electrodes that can be reversibly deformed over 100 percent without losing electrical conductivity are needed for high stroke artificial muscles, and the Science article describes a simple method that makes this possible for the nanotube sheets.

The use of the nanotube sheets as planar incandescent sources of highly polarized infrared and visible radiation is also reported in the Science article. Since the nanotube sheets strongly absorb microwave radiation, which causes localized heating, the scientists were able to utilize a kitchen microwave oven to weld together plexiglas plates to make a window. Neither the electrical conductivity of the nanotube sheets nor their transparency was affected by the welding process -- which suggests a novel way to imbed these sheets as transparent heating elements and antennas for car windows. The nanotube sheets generate surprisingly low electronic noise and have an exceptionally low dependence of electronic conductivity on temperature. That suggests their possible application as high-quality sensors – which is a very active area of nanotube research.

“Rarely is a processing advance so elegantly simple that rapid commercialization seems possible, and rarely does such an advance so quickly enable diverse application demonstrations,” said the article’s corresponding author, Dr. Ray H. Baughman, Robert A. Welch Professor of Chemistry and director of the UTD NanoTech Institute. “Synergistic aspects of our nanotube sheet and twisted yarn fabrication technologies likely will help accelerate the commercialization of both technologies, and UTD and CSIRO are working together with companies and government laboratories to bring both technologies to the marketplace.”

The breakthroughs resulted from the diverse expertise of the article’s co-authors. Dr. Mei Zhang and Dr. Shaoli Fang, NanoTech Institute research scientists, first demonstrated the nanotube sheet fabrication process, and this result was translated into diverse applications by the entire team. The other team members include Dr. Anvar Zakhidov, associate director of the NanoTech Institute; Christopher Williams, Zakhidov’s graduate student from the UTD Physics Department; Dr. Sergey Lee and Dr. Ali Aliev, research scientists at NanoTech Institute, in addition to Atkinson and Baughman.

The applications possibilities seem even much broader than the present demonstrations, Baughman said. For example, researchers from the Regenerative Neurobiology Division at Texas Scottish Rite Hospital for Children, Dr. Mario Romero, Director, and Dr. Pedro Galvan-Garcia, Senior Researcher Associate, and Dr. Larry Cauller, associate professor in UTD’s neuroscience program, have initial evidence suggesting that healthy cells grow on these sheets – so they might eventually be applied as scaffolds for tissue growth.

Baughman said that numerous other applications possibilities exist and are being explored at UTD, including structural composites that are strong and tough; supercapacitors, batteries, fuel cells and thermal-energy-harvesting cells exploiting giant-surface-area nanotube sheet electrodes; light sources, displays, and X-ray sources that use the nanotube sheets as high-intensity sources of field-emitted electrons; and heat pipes for electronic equipment that exploit the high thermal conductivity of nanotubes. Multifunctional applications like nanotube sheets that simultaneously store energy and provide structural reinforcement for a side panel of an electrically powered vehicle also are promising, he said.

UTD researchers began collaborating with their counterparts at CSIRO last year. In November 2004, the organizations achieved a breakthrough by downsizing to the nanoscale methods used to spin wool and other fibers to produce futuristic yarns made from carbon nanotubes.

The latest research was funded by the Defense Advanced Research Projects Agency, an agency of the United States Department of Defense, the U.S. Air Force Office of Scientific Research, the Texas Advanced Technology Program, the Robert A. Welch Foundation and the Strategic Partnership for Research in Nanotechnology.

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2005 Seed Grants Launch New Collaborations Between Argonne National Laboratory, University of Chicago

The University of Chicago’s Board of Governors for Argonne National Laboratory has selected seven proposals for 2005 Collaborative Research Seed Grants of $80,000 to $100,000 each. The grants are renewable for a second year.

The awardees come from three divisions of the University and its medical school and six divisions at Argonne. Five of the awards involve researchers in more than one discipline, such as chemistry and biosciences, or anthropology and energy technology. They are the most recent beneficiaries of a program that began in 1996 to enhance the intellectual relationship between the University and Argonne, which have been research partners since the latter was established as the nation’s first national laboratory in 1946.

Argonne is operated by the University of Chicago for the U.S. Department of Energy’s Office of Science and has been the University’s research partner throughout its history. Argonne was formed in 1946 as an outgrowth of the Manhattan Project’s Metallurgical Laboratory at the University of Chicago, which in 1942 produced the first controlled, self-sustaining nuclear chain reaction.

The 2005 awardees and their projects are:

• Rustem Ismagilov, University of Chicago Chemistry Department, and Philip Laible, Argonne’s Biosciences Division, “Microfluidic strategies for high-throughput crystallization of membrane proteins.”
• Lin Chen, Argonne’s Chemistry Division, and Luping Yu, University of Chicago Chemistry Department, “Fundamental electronic processes and rational design of novel organic photovoltaic materials for future generation of solar cells.”
• Henry Frisch, University of Chicago Physics Department, and Carlos Wagner, Argonne’s High Energy Physics Division, “Joint institute on high energy collider physics.”
• Melina Hale, University of Chicago’s Organismal Biology & Anatomy Department, and Wah-Keat Lee, Argonne’s Advanced Photon Source, “Use of the Advanced Photon Source to identify physiological and functional anomalies in Drosophila models of disease and development.”
• William Ellingson, Argonne’s Energy Technology Division, Adam T. Smith, University of Chicago’s Anthropology Department, “The making of ancient Eurasia: Objects within and between the social worlds of the Caucasus, the Steppe and China.”
• Chin-tu Chen, the University of Chicago’s Radiology Department, and Liaohai Chen, Argonne’s Biosciences Division, “Radiophage: A new generation of radiotracer and molecular imaging.”
• Andrew Davis, the University of Chicago’s Geophysical Sciences Department, and Zheng-Tian Lu, Argonne’s Physics Division, “Proposal to develop a novel atom counter for applications in cosmochemistry and geochemistry.”

The seed grant to Ismagilov and Laible will combine two unique technologies, microfluidics from the University and membrane protein expression from Argonne, to expedite the study of important biological processes at the molecular level.

The team is especially interested in determining the three-dimensional structure of membrane proteins, which help regulate what goes into or out of a cell, using the high-brilliance X-rays of the Advanced Photon Source at Argonne. Once the sample materials are obtained using Argonne’s membrane protein expression techniques, it takes weeks or months to produce crystals suitable for structural analysis.

Ismagilov and Laible aim to cut down crystal-production time to days using microfluidics, a technology that enables researchers to precisely control the flow of fluids through channels thinner than a human hair.

Hale and Lee will use the Advanced Photon Source to learn how genetic mutations affect the biomechanics and physiology of fruit flies. This study will be done in collaboration with Urs Schmidt-Ott in the University’s Department of Organismal Biology & Anatomy, Kamel Fezzaa at the Advanced Photon Source, and of the Field Museum and the University’s Committee on Evolutionary Biology.

In earlier research involving beetles and ants, Lee and Westneat demonstrated that the Advanced Photon Source can produce detailed X-ray images of the internal structures of living insects. In its follow-up studies, the team will focus on Drosophila, the fruit fly, a genetic and developmental model organism.

The researchers also will examine how tracheae that have mutated into odd forms in fruit flies affect their breathing.

The grant to Ellingson and Smith will enable the duo to analyze ancient artifacts with a variety of innovative scientific instruments at Argonne to gain new insights into how the artifacts were manufactured and used. Which instruments to be used will depend upon the material in question.

This technology will include an X-ray CAT scanner built at Argonne that generates three-dimensional images. The research team also may use some of Argonne’s patented laser-based analysis systems, or its advanced ultrasound systems.

Ellingson and Smith also will use the high-brilliance X-rays of the Advanced Photon Source at Argonne to analyze large assemblages of materials. The seed grant program has awarded $6.6 million in research funding since the 1996 and has helped bring about several ongoing collaborations. These include the Center for Astrophysical Thermonuclear Flashes (involving Argonne’s Mathematics and Computer Science Division, the University’s Department of Astronomy & Astrophysics, and other departments); the Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (three Argonne divisions, three University departments and 19 other upper-Midwest institutions); and a project for modeling ancient settlement systems (Argonne’s Decision and Information Systems Division and the University’s Oriental Institute).

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U. T. Dallas’ Brian Berry to Receive World’s Top Honor for Geographers

Dr. Brian J. L. Berry, dean of the School of Social Sciences at The University of Texas at Dallas (UTD), has been named the 2005 recipient of the Vautrin Lud Prize, the highest award that can be bestowed on a geographer. Berry will receive the award at a ceremony on Sept. 29 at the International Festival of Geography in Saint-Dié-des-Vosges, France.

The prize, which was created in 1991 and is officially known by its French name Lauréat Prix International de Géographie Vautrin Lud, is awarded each autumn to an intellectual leader in the field, as determined by a five-person international jury.

The award is modeled after the Nobel Prize, which does not have a category for geography. Vautrin Lud was a French scholar who was instrumental in naming America for the Florentine navigator Amerigo Vespucci, whose account of landing on the North American continent found its way to a group of Saint-Dié-des-Vosges scholars directed by Lud. In 1507, the group used Vespucci’s accounts to publish one of the earliest geographical treatises regarding the New World.

Berry is one of the world’s leading social scientists, widely acclaimed for his work with spatial analysis and urban theory. He is credited with helping transform geography as a discipline, elevating it to a respected and competitive science. Due to the groundbreaking nature of his work, Berry was ranked as the world’s most frequently cited geographer for more than a quarter century.

Berry is the Lloyd V. Berkner Regental Professor in UTD’s School of Social Sciences and a long-time leader of the university’s political economy program. On July 1, he became dean of the school, which has 60 faculty members and more than 1,300 students and which offers bachelor’s, master’s and doctoral degrees in a broad range of fields, including crime and justice studies, economics and finance, geospatial science, political science, public administration, public policy and sociology.

Berry became a faculty member at UTD in 1986, after holding faculty and administrative positions at Carnegie Mellon University (where he also served as a dean), Harvard University and the University of Chicago. He helped found and was the first director of UTD’s Bruton Center for Development Studies.

Among the many awards and other forms of recognition Berry has received for his work are the Victoria Medal bestowed by Britain’s Royal Geographical Society in 1988 and his election as a Fellow in the British Academy in 1989. In 1975, he became the youngest social scientist ever elected to the National Academy of Sciences, the most prestigious scientific association in the United States, and in 1999 he became the first geographer elected to the academy’s council.

A native of England, Berry earned a B.Sc. degree in economics from University College, London. He received a M.A. degree and a Ph.D. degree, both in geography, from the University of Washington, Seattle.

He is the author of more than 500 books, articles and other professional publications.

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UTMB Pediatrician Garners International Award

Dr. Rueben Matalon, professor of pediatric cytogenetics at the University of Texas Medical Branch at Galveston, recently received a rare honorary professorship from Kharkiv National University Medical School in Ukraine. The award recognizes Matalon’s work with Ukrainian physicians and health officials to establish screening and treatment programs for infants with phenylketonuria (PKU), a dangerous, genetic metabolic disorder.

Ukrainian physicians at the university’s Center for Genetics contacted Matalon in 2002 to get his expert advice on starting a PKU program. Matalon began working with them long-distance, and he now advises on PKU screening equipment, screening procedures and diet treatments. He has made three trips to the university, giving lectures and assisting with PKU patients. He also has appeared on Ukrainian national television and has met Ukrainian Deputy Minister of Health, Rayisa Bohatyrova.

PKU affects only one out of every approximately 10,000 babies born in the U.S. Without proper screening and treatment within the first weeks of life, the disorder—which renders the body unable to metabolize the essential amino acid, phenylalanine—results in mental retardation and other neurological problems. When a very strict diet is begun early and well-maintained, affected children can expect normal development and a normal life span.

Newborn screening for PKU began in the United States in the mid-1960s, and today it is routinely carried out in every state and in many other countries. Matalon is helping health officials in the Ukraine to make screening and treatment programs available there as well.

Matalon, a pediatrician at UTMB Children’s Hospital, will return to Kharkiv in October to serve as president of the Second Ukrainian Congress on Clinical Genetics. The meeting is sponsored by the Ukraine’s Ministry of Health, the Kharkiv Regional State Administration, the Kharkiv Municipal Executive Committee, the Kharkiv State Medical University and the Kharkiv Medical-Genetic Centre, and calls together internationally renowned scientists looking for ways to detect and treat rare diseases such as PKU.

Kharkiv National University is one of Eastern Europe’s oldest institutions of higher education. Three Nobel laureates sit on its faculty, and Matalon shares the school’s honorary professorship distinction with such legends as German poet Johann W. Goethe, German geographer Alexander von Humboldt, and Russian novelist Leo Tolstoy. Founded in 1804, the university has awarded degrees to more than 130,000 students.

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Richard Billo Named Associate Dean of Engineering at UTA

University of Texas at Arlington Dean of Engineering Dr. Bill Carroll has announced the appointment of Richard E. Billo as Associate Dean of Engineering for Research. Dr. Billo was formerly the Intel Faculty Fellow and chair of the Department of Industrial and Manufacturing Engineering at Oregon State University.

Billo received his Ph.D. from Arizona State University, where he concentrated on Information Systems Engineering. He also holds a master’s degree in Organizational Management from the University of the Pacific and has a distinguished career in education and industrial consulting.

Billo is a known innovator in engineering education, receiving a commendation from the Accreditation Board for Engineering and Technology for his leadership in curriculum development. At Oregon State, he developed a new bachelor’s degree program in manufacturing engineering, created undergraduate options in information systems and business engineering, and modernized the graduate curriculum to include information systems, nanotechnology, management systems and manufacturing systems.

Also at Oregon State, Billo directed a $20 million fundraising campaign for nanoscience and microtechnology programs and secured more than $16 million in new research grants and gifts. Research expenditures tripled during his four years of leadership of the Department of Industrial and Manufacturing Engineering.

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Sapiro Named Interim Provost at UW-Madison

Virginia Sapiro, associate vice chancellor for teaching and learning at UW-Madison, will become interim provost and vice chancellor for academic affairs when Provost Peter Spear retires in late October, Chancellor John D. Wiley announced Wednesday.

In June, Wiley appointed a search and screen committee to help find Spear's successor. Leading that effort is Mary Behan, professor and chair of the Department of Comparative Biosciences.

Sapiro, a political scientist and former chair of the Department of Political Science and the Women's Studies Program, has been on the faculty since 1976. She has served as associate vice chancellor since 2002; in that post, she assists the provost and works with deans, directors and campuswide groups to carry out UW-Madison's teaching and learning missions. Her associate vice chancellor position will not be filled during her interim appointment.

Spear announced his retirement in April. He recently moved up the timing of his departure from the end of December to the end of October.

Spear has served on the faculty since 1976, except for a five-year period as dean of the College of Arts and Sciences at the University of Colorado at Boulder. He returned to UW-Madison in 2001 to assume his current position as provost and vice chancellor. He will continue to handle all of the duties of this position until his departure.

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Three Finalists Named for Dean of UGA Veterinary College

Three finalists have been chosen for the position of dean of the University of Georgia College of Veterinary Medicine. They will be visiting campus beginning Aug. 17 to meet with college faculty, staff and students and to present a seminar.

The new dean will fill the vacancy created when Keith Prasse retired March 1 after serving as dean for nine years.

Each candidate will present a seminar titled “View of the Future of Veterinary Medicine” at 10 a.m. in room H237 of the veterinary college building. The candidates and the dates of their visits are:

* Lee Myers, state veterinarian and assistant commissioner of animal industry with the Georgia Department of Agriculture, Aug. 17.

* Kent Hoblet, professor and chair of the department of veterinary preventative medicine in the Ohio State University College of Veterinary Medicine, Sept. 8

* Sheila Allen, interim dean of the UGA College of Veterinary Medicine and former associate dean for academic affairs in the college, Sept. 19.

The candidates were identified in a national search conducted by a 19-member committee that includes faculty, staff, a student and two alumni. Richard Porterfield, dean of UGA’s Warnell School of Forest Resources and chair of the committee, said the goal is to have a new dean chosen during fall semester.

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Customized Y-Shaped Carbon Nanotubes Can Compute

Researchers at UCSD and Clemson University have discovered that specially synthesized carbon nanotube structures exhibit electronic properties that are improved over conventional transistors used in computers. In a paper published in the September issue of Nature Materials and released online on August 14, UCSD engineering professors Prabhakar Bandaru and Sungho Jin, graduate student Chiara Daraio, and Clemson physicist Apparao M. Rao reported that Y-shaped nanotubes behave as electronic switches similar to conventional MOS (metal oxide semiconductor) transistors, the workhorses of modern microprocessors, digital memory, and application-specific integrated circuits.

The stunning increase in the speed and power efficiency of electronics over the past two decades was primarily due to the steady shrinkage in size of conventional transistors. Chip makers have reduced the minimum feature size of transistors to about 100 nanometers, and that dimension is expected to shrink by the end of this decade. However, industry experts predict that fundamental technological and financial limits will prevent the makers of conventional MOS transistors to reduce their size much further. However, the Y-shaped nanotubes discussed in the Nature Materials paper are only a few tens of nanometers thick and can be made as thin as a few nanometers.

The new transistors were initially grown as straight nanotube elements. Titanium-modified iron catalyst particles added to the synthesis mixture are then attached to the straight nanotubes, nucleating additional growth, which continued like branches growing from a tree trunk. Consequently, the nascent nanotubes assumed a Y-shape with the catalyst particle gradually becoming absorbed at the junction of the stem and two branches.

When electrical contacts are attached to the nanotube structures, electrons travel into one arm of the Y, hop onto the catalyst particle, and then hop to the other arm and flow outward. Experiments conducted in Bandaru’s lab at UCSD’s Jacobs School of Engineering showed that the movement of electrons through the Y-junction can be finely controlled, or gated, by applying a voltage to the stem. Bandaru hypothesized that positive charge applied to the stem enhances the flow of electrons through the two arms, producing a strong “on” signal. However, when the polarity of the charge is reversed, the movement of electrons through the arms essentially stops, creating an “off” signal. Such binary logic is the basis of nearly all transistors.

“Among electrical device engineers, this phenomenon is called gating,” said Bandaru. He said the phenomenon effectively makes Y-shaped nanotubes the smallest ready-made transistor yet, with rapid switching speeds and possible three-way gating capability. In earlier attempts to make carbon nanotube-based transistors, separate gates were added rather than built in.

“We think this discovery extends the paradigm of nanotechnology beyond just making things small,” said Bandaru. “We can synthesize functionality at the nanoscale, in this case to include the three elements of a circuit – the gate, source, and drain – and we don’t have to go to the trouble of making them separately and assembling them.”

The researchers plan to experiment with various other catalyst particles in order to tailor the three-way gating properties of the Y-junctions. “If we can easily fabricate, manipulate, and assemble these nano-devices on a large scale they could become the basis of a new kind of transistor and nanotechnology,” said Bandaru.

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Soft Body Fossils of Extinct “Lamp Shell” Digitally Reconstructed

A team of American and British scientists have identified and digitally reconstructed the first example of a fossilized brachiopod complete with its pedicle, the stalk attaching it to the sea floor, and its lophophore or feeding organ, according to a report in the journal Nature.

Brachiopods, the so called “lamp shells,” are rare today, but are some of the best known fossils from the Paleozoic era — 542 to 251 million years ago. Our knowledge of these extinct forms was previously based almost entirely on their shells, which are all that normally fossilize.

Derek Briggs, professor of geology and geophysics, and director of the Yale Institute of Biospheric Studies, with his colleagues Mark Sutton at the Imperial College, University of London, Derek Siveter at University of Oxford and Professor David Siveter at University of Leicester conducted their research on the fossil deposits in Herefordshire, U.K.

This extraordinary trove of fossil records was buried under the sea in volcanic ash that is 425 million years old. The site is unusual because it yields fossils of the entire animals, including soft body parts that the researchers then can reconstruct digitally.

The brachiopod belongs to an extinct group, and this work reveals that its pedicle differs from that on living forms. Previous assumptions that extinct brachiopods were very similar to modern examples may thus be too simplistic.

Other specimens of interest from the volcanic ash at Herefordshire that were recently reconstructed by the team include an ancient sea spider and the oldest fossil animal that is “definitively male.”

This work was supported by the Leverhulme Trust, Natural Environment Research Council and English Nature.

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Study Reveals a Way Disease Bacteria Initiate Counter-Defense

Many living things, from fruit flies to people, naturally produce disease-fighting chemicals, called antimicrobial peptides, to kill harmful bacteria. In a counter move, some disease-causing bacteria have evolved microbial detectors. The bacteria sense the presence of antimicrobial peptides as a warning signal. The alarm sets off a reaction inside the bacteria to avoid destruction.

University of Washington (UW) and McGill researchers have revealed a molecular mechanism whereby bacteria can recognize tiny antimicrobial peptide molecules, then respond by becoming more virulent. Their studies were done on the bacterium Salmonella typhimurium. The findings were published in the Aug. 12 edition of the journal Cell.

Salmonella typhimurium can contaminate meats such as beef, pork, and chicken, as well as cereals and other foods, and cause severe intestinal illness. Certain strains of the bacteria are difficult to treat, and are behind the increase of salmonellosis in people. Some food science institutes anticipate that virulent strains of salmonella will become more common throughout the food chain. Learning how this sometimes deadly organism fights back against the immune system may lead to treatments that get around bacterial resistance.

Work in this area may also suggest ways other disease-causing Gram-negative bacteria maintain a stronghold in the midst of the body's attempts to get rid of them.

Strangely enough, the same molecules that the body sends out to help destroy salmonella inadvertently launch bacterial defenses. It is as if missles armed, rather than demolished, the target. The body's antimicrobial peptides bind to an enzyme, PhoQ, which acts as a watchtower and interceptor near the surface of bacterial cell membranes. The peptide binding activates PhoQ, which sets off a cascade of signals. The signals turn on a large set of bacterial genes. Some of the genes are responsible for products that fortify the bacterial cell surface and protect the bacteria from being killed.

The research was done in the UW laboratory of Dr. Samuel Miller, professor of microbiology and of medicine, Division of Infectious Diseases. The Miller Lab explores the molecular aspects of bacteria-induced illness, and how disease-causing bacteria interact with cells in the host they have infected, and adapt to environments inside the body, such as the airway.

The lead author of the August 12 Cell article was Dr. Martin Bader, a UW senior fellow in microbiology and genome sciences. The research team, under the direction of Miller, included Dr. Sarah Sanowar of the Department of Microbiology and Immunology at McGill University; Dr. Margaret Daley, a UW senior fellow in biochemistry; Anna SChneider, a UW undergraduate majoring in mathematics and biochemistry; Uhn Soo Cho, a graduate studenty in biological structure; Dr. Wenqing Xu, assistant professor of biological structure; Dr. Rachel Klevit, professor of biochemistry; and Dr. Herve Le Moual on the McGill Faculty of Dentistry.

Grants from the National Institute of Allergy and Infectious Diseases and from the Canadian Institutes of Health Research funded the study.