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September 30, 2004

Research Notes

NFS grant awarded to SIS

Pitt’s School of Information Sciences (SIS) is developing a Security Assured Information Systems (SAIS) curriculum to teach students to design secure and reliable computer systems and networks. SIS received a two-year, $286,710 award from the National Science Foundation, to build on existing multidisciplinary strengths in computer science, intelligent systems, and other areas within SIS’ Department of Information Science and Telecommunications.

“We’ll be training the cadre of engineers and scientists who will ensure that every computer user in this country will some day receive the same kind of reliable service that we’ve come to expect from the telephone system,” said SIS Associate Professor Michael Spring, one of four co-investigators on the SAIS project. “That’s a lofty goal, but it’s based on the simple fact that what hackers do is exploit weaknesses in software design. If the software is designed right from the start, it’s impervious to attack.”

With the Internet’s global reach, Spring noted, it’s currently all-too-easy for a lone hacker in Asia or Europe to infect a desktop computer in Pennsylvania just by exploiting a tiny, inadvertent coding error made years ago.

Faculty from the Department of Information Science and Telecommunications will develop four SAIS courses to add to three already being offered, and will add SAIS content to a dozen existing graduate and undergraduate courses. James B.D. Joshi, another co-principal investigator on the SAIS project, said, “There is general agreement, both within our school and the National Science Foundation, that information security cannot be treated as a separate discipline but must be developed by incorporating it into various disciplines.” By fall 2006, about 20 percent of the content of every course offered by Pitt’s Department of Information Science and Telecommunications will be devoted to security issues, Joshi said.

All three of the SAIS courses that Pitt currently offers have been certified by the U.S. government’s Committee on National Security Systems (CNSS) as meeting national standards for instruction of information systems security professionals, including system administrators. Pitt also will seek CNSS certification for the four new SAIS courses that the University plans to offer.

According to Spring, creating impervious software is a very achievable goal; it simply wasn’t as important in the past as making software user friendly, which sometimes was accomplished at the expense of security. Spring compared the software code-writing process to crafting a grammatically perfect English sentence. “If, in effect, you dangle a participle in computer programming, you may allow a hacker to get into a user’s computer and violate it,” Spring noted.

In addition to Spring and Joshi, co-principal investigators on the SAIS project are SIS Assistant Professor Prashant Krishnamurthy and Associate Professor David Tipper, each of whose research focuses on network aspects of security, particularly as related to wireless networks.

Pitt’s SAIS award, made by the National Science Foundation’s Division of Undergraduate Education, took effect Sept. 1.

Researchers create self-assembling nanotubes

Pitt researchers have synthesized a simple molecule that not only produces perfectly uniform, self-assembled nanotubes but creates what they report as the first “nanocarpet,” whereby these nanotubes organize themselves into an expanse of upright clusters that when magnified a million times resemble the fibers of a shag rug. Moreover, unlike other nanotube structures, these tubes display sensitivity to different agents by changing color and can be trained to kill bacteria, such as E. coli, with just a jab to its cell membrane.

How a single-step synthesis of a hydrocarbon and a simple salt compound produced these unique nanotube structures with antimicrobial capability is described in a paper posted on the Web site for the Journal of the American Chemical Society. The findings have implications for developing products that can simultaneously detect and kill biological weapons.

“In these nanotube structures, we have created a material that has the ability to sense their environment. The work is an outgrowth of our interest in developing materials that both sense and decontaminate chemical or biological weapons,” said senior author Alan J. Russell, professor of surgery at Pitt’s School of Medicine and director of the University’s McGowan Institute for Regenerative Medicine.

The research, funded by the Department of Defense’s Army Research Office, has as its goal the development of a paint that in the event of biological or chemical agents being deployed would change color and simultaneously destroy the deadly substances.

The researchers thought that by combining a chemical structure called a quarternary ammonium salt group, known for its ability to disrupt cell membranes and cause cell death, with a hydrocarbon diacetylene, which can change colors when appropriately formulated, the resulting molecule would have the desired properties of both biosensor and biocide. Remarkably, in addition to being able to kill cells, the resulting reaction mixture has the ability to self assemble into beautiful nanotubes of uniform structure. After searching for what was forming the tubes, the researchers discovered that synthesis of a secondary salt and diacetylene, thereby creating a lipid molecule, also resulted in production of absolutely pure self-assembling nanotubes, all having the same diameter (89 nanometers) and wall thickness (27 nanometers). By comparison, a human hair is about 1,000 times wider.

When dried from water and other solvents, and under magnification, these nanostructures look much like a heaping serving of macaroni or ziti pasta. When coaxed with simple processing, the tubes align into the more formal pattern of a nanocarpet. Just like any rug, a backing, also self-assembled from the same material, holds it all together. The nanocarpet measures about one micrometer in height, approximately the same height as the free-form nanotubes.

“This alignment of nanotubes in the absence of a template is an accomplishment that has eluded researchers,” said Dr. Russell, who also is a professor of chemical and bioengineering at the University of Pittsburgh School of Engineering.

“To our knowledge, the remarkable self-assembly of this inexpensive and simple lipid is unprecedented and represents an important step toward rational design of bioactive nanostructures. In addition, because they form within hours under room-temperature conditions, the significant costs of synthesizing carbon nanotubes can be reduced,” explained Sang Beom Lee, research assistant professor of bioengineering in the School of Engineering, who is listed as first author.

To test the nanostructure’s potential as a biosensor and antimicrobial, the authors conducted studies using the water-based nanotubes. Normally a neutral color, when exposed to ultraviolet light the nanotubes changed to a permanent deep blue. The process also chemically altered the nanotubes so that they became polymerized, giving them a more firm structure. Polymerized, these nanotubes could change from blue to other colors, depending on its exposure to different materials. For instance, in tests with acids and detergents, they turned red or yellow.

The most critical tests, say the researchers, were those involving E. coli, which were conducted to assess the material’s interactions with living cells. In the presence of E. coli, some strains of which are food-borne pathogens, the nanotubes turned shades of red and pink. Moreover, with the aid of an electron microscope, the researchers observed the tubes piercing the membranes of the bacteria like a needle being inserted into the cell. Both the polymerized (those that can change color) and the unpolymerized nanotube structures were effective antimicrobials, completely killing all the E. coli within an hour’s time.

In addition to Russell and Lee, other authors, all from Pitt, include Richard Koepsel, department of chemical and petroleum engineering, School of Engineering; Donna B. Stolz, Center for Biologic Imaging, School of Medicine, and Heidi E. Warriner, department of chemistry, School of Arts and Sciences.

Filed under: Feature,Volume 37 Issue 3

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