On the web

Virginia Tech Magazine's online feature, "On the Web," gives Web-savvy readers more news and stories about some of the exciting things happening at the university today. "On the Web" will be updated with Web-only content on a quarterly basis.

by Susan Trulove

Scientists interested in ancient life have a wealth of fossils and impressions frozen in rocks that they can study from as far back as 540 million years ago--when animals with shells and bones began to become plentiful. But evidence of complex life older than 540 million years is scant and difficult to study.A research team from Virginia Tech in the United States and Nanjing Institute of Geology and Paleontology in China has discovered uniquely well-preserved fossils form from 550-million-year-old rocks of the Ediacaran Period. Shuhai Xiao, geoscientist from Virginia Tech, with Bing Shen, a Virginia Tech graduate student, and Chuanming Zhou, Guwei Xie, and Xunlai Yuan, all of the Nanjing Instititue of Geology and Paleontology, report in the Proceedings of the National Academy of Sciences (PNAS) the discovery of these unusually preserved fossils, which reveals unprecedented information about the body construction of macroscopic organisms more than half billion years ago. The article has been published in the PNAS Online Early Edition the week of July 11-15.


Ediacara fossils, named after Ediacara Hill in the Flinders Ranges of South Australia where such fossils are best known, are some of the oldest fossils with large body size and complex morphology. "Present in rocks ranging from 575 to 540 million years in age, these fossils provide the key to understand the prelude to the Cambrian Explosion when animals with skeletons and familiar morphologies began to bloom about 540 to 520 million years ago," Xiao said. "However, classic Ediacara fossils are mostly preserved in sandstone, and the coarse sand grains limit how much we can learn about the fine-scale morphologies of these fossils."

Partly because of this limitation, scientists cannot agree on the fine-scale anatomy of Ediacara organisms and have been debating for decades their relationships with animals and other macroscopic life forms. Traditionally, Ediacara organisms are thought to be related to such animals as jellyfishes and worms. Other scientists, however, believe that they may be plants or fungi. Twenty years ago, however, Adolf Seilacher, a paleontologist now retired from University of Tubingen (Universität Tübingen) and Yale University, argued that many Ediacara organisms were built of tube-like elements and are only distantly related to living animals. "But direct observation of the hypothesized tube-like elements has been difficult because such tubes tend to be deflated and squashed prior to their preservation in sandstones," Xiao said.

This may change with the new discovery of Ediacara fossils from fine-grained limestone of the Dengying Formation in South China by Xiao and his collaborators. "The Ediacara fossils from China were not deflated before they were incorporated in the rock," Shen said. "Instead, they are preserved three-dimensionally in the rock." Using serial thin sectioning techniques, Shen and Xiao cut the decimeter-sized fossils into many paper-thin slices and looked at them under a microscope. They saw organic remains of millimeter-sized tubes that were the building blocks of the Ediacara fossils from China. Their discovery thus directly confirms Seilacher's hypothesis.

The new fossils also help to refine the Seilacher hypothesis. Seilacher originally hypothesized that Ediacara tubes had closed ends and were filled with cytoplasm, or cell contents. The fossils from China, however, appear to have an open end that is connected with the external environment. Thus, Xiao and his colleagues infer that the tubes of their Ediacara fossils were probably not filled with cytoplasm.

Ediacara organisms had no shells or bones. How could such soft and delicate organisms be preserved in rocks? Working with geosciences professor Fred Read at Virginia Tech, geology professor Guy Narbonne at Queen's University, and paleontologist James Gehling at South Australia Museum, Xiao and his colleagues carefully examined the calcite crystals that replicate the tubes. They believe that the crystals were emplaced shortly after the death, burial, and decay of the Ediacara organisms, thus replicating the three-dimensional shape of the tubular structures.

How did these Ediacara organisms live? "We think that the fossils were preserved where they lived. In other words, they had not been transported a long way from their deathbed to their graveyard." Zhou said. "And the way they occur in the rocks suggests that they were flat-lying organisms sprawling on the ocean floor 550 million years ago, much like some fungi, lichen, or algae do today."

The resemblance to modern fungi, lichen, or algae may stop at the seemingly similar life position on ocean floor. "In fact, the morphology of the new fossils is unlike any living macroscopic life," Xiao said, "and at this time it is still uncertain how the Ediacara fossils from South China are related to other Ediacara organisms and to living organisms."

But the new fossils surely will enlighten the ongoing debate on the nature of Ediacara organisms that lived just before the evolution of familiar animals about 540 to 520 million years ago.

For more on the project, go to http://www.geol.vt.edu/paleo/Xiao/.

by Sally Harri

Virginia Tech's new Multicultural Programs and Services unit, established July 1 following the merger of two existing offices and other resources dedicated to multicultural issues, will approach student growth and development holistically, said Karen Eley Sanders, assistant provost and director of Academic Support Services.

As a result of this new structure, Multicultural Programs and Services will provide an educational focus that will include institutionalized partnerships with the Africana Studies Program, the Center for Academic Enrichment and Excellence, the Department of Interdisciplinary Studies, and the Race and Social Policy Research Center. The new administrative unit will now encompass academic-support services, education and research, and advocacy, as well as advising and cultural programs.

"It's an exciting opportunity," Sanders said. "We'll be able to create an environment at Virginia Tech that is more welcoming, supportive, and inclusive, and one that addresses the transition and support issues that led some of our constituent groups to feel their needs are not being met."

Besides increasing the efficiency in coordinating and delivering services and programs to Virginia Tech's diverse student body, Multicultural Programs and Services will add to the positive diversity climate by increasing the visibility of programs and services. It will help retain students, develop and expand on-campus partnerships, aid in the recruitment and retention of faculty "as a demonstration of the university's commitment to diversity," send a positive message to alumni about the university's commitment to serving a diverse student body, and enhance Virginia Tech’s national message of providing a positive climate for all students.

Karen Eley SandersKaren Eley Sanders

Multicultural Programs and Services will support programs and activities specific to the interest of unrepresented groups. Such things as arts events, concerts, educational programs, and development opportunities will provide an academic, social, and emotional support to help students feel comfortable and be successful on campus, Sanders said.

The new unit will oversee the Black Cultural Center and Multicultural Center (located in Squires Student Center), cultural-awareness programs, advising for multicultural student organizations (Black Student Alliance, Asian American Student Union, Latino Association of Student Organizations, and Lesbian, Gay, Bisexual, Transgender Alliance), education and research, advocacy, and recruitment and retention.

In its first year, Multicultural Programs and Services will focus on cultural celebrations, entertainment, film series, lecture series, and awareness of such things as disabilities and the Holocaust.

Multicultural Programs and Services also will work with faculty to help them infuse multiculturalism into their classes. Besides providing multicultural support, Multicultural Programs and Services will educate other students, faculty, and staff about multicultural programs on campus, where programs can be part of the academic and intellectual development of the 26,000 students and more than 5,000 faculty and staff.

"We want Multicultural Programs and Services to be fully integrated into the life of the campus, not marginalized or separate," Sanders said. "We want to serve the entire Virginia Tech community."

A new director of Multicultural Programs and Services will be hired and will report to Sanders. An assistant director for advising, an assistant director for programming, a coordinator of academic support (who will be shared with the Center for Academic Enrichment and Excellence), as well as those to provide office and technical support, graduate assistants for programming and advising, and work-study students will round out the staff. Personnel from the merging areas will fill most of those positions.

Multicultural Programs and Services was established following the consolidation of several positions that were a part of the Division of Student Affairs. Specifically, the assistant director of cultural programs (formerly in Student Activities) and the coordinator of multicultural programs (formerly in the Student Life Office), will become a part of Multicultural Programs and Services. The new unit will be a part of the Division of Academic Affairs.

by Sally Harris

Expansion ManagementThe Blacksburg/Christiansburg/Radford area is among the communities cited in Expansion Management magazine's third annual "Knowledge Worker Quotient," a designation that "identifies metro areas that are exceptionally well placed to attract and nurture high-tech companies and entrepreneurs because of their concentration of extremely well-educated workers."

In the accompanying article, "America's Super Cities of the Future," the Blacksburg/Christiansburg/Radford area placed second in the category of "Top Metros: Ph.D.s Per Capita," following only Ithaca, N.Y. The area also placed 14th in the category of "Best Educated Technical Work Force." Blacksburg/Christiansburg/Radford also made the list of "Five-Star Knowledge Worker Metros."

"Clearly," the story by Chief Editor Bill King and Senior Research Editor Michael Keating said, "having a well-educated work force--engineers, scientists, Ph.D.s--in proximity to a major university, with its world-class faculty and buckets of R&D [research and development] dollars, is a major drawing card for technology-driven companies in the Knowledge Economy."

The full article can be found on Expansion Management magazine's website at http://www.expansionmanagement.com/smo/articleviewer/default.asp?cmd=articledetail&articleid=16423&st=2

by Liz Crumbley

Sandeep Shukla, an assistant professor in the Bradley Department of Electrical and Computer Engineering at Virginia Tech, is among 88 of the nation's outstanding young engineers invited by the National Academy of Engineering (NAE) to participate in the 11th annual Frontiers of Engineering Symposium, Sept. 22-24 at the General Electric Research Center in Niskayuna, N.Y.

Sandeep ShuklaShukla and the other attendees--engineers 30 to 45 years of age and representing academia, industry, or government--were nominated and selected in recognition of their contributions to the advancement of engineering and their potential as future leaders in their fields.

Shukla, who came to Virginia Tech in 2002, is a leading researcher in designing, analyzing, and predicting performance of electronic systems, particularly systems embedded in automated systems. In September 2004, he was honored at the White House as a recipient of a Presidential Early Career Award for Scientists and Engineers (PECASE), which is the highest national honor for researchers in the early stages of their careers.

"The computing world is moving from the desktop and workstation to an arena of embedded and wearable computers," Shukla said. More and more, embedded computers are becoming the brains behind mechanisms that we rely on in our everyday lives--such as wireless devices, cars, automated elevators, climate control systems, traffic signals, and washing machines. Embedded computers also constitute the backbone of our complex systems, including space mission controls, avionics, and weapons systems.

In 2003, Shukla and a group of colleagues in electrical and computer engineering, computer science, and mathematics founded the Center for Embedded Systems for Critical Applications with the goal of moving Virginia Tech to the forefront of research and education in the area of embedded systems.

Shukla received his bachelor's degree in computer science and engineering from Jadavpur University in India and his master's degree and Ph.D. in computer science from the State University of New York at Albany. He began studying embedded computers while working as an engineer with Verizon and, later, Intel. Before coming to Virginia Tech, he was a member of the research faculty of the Center for Embedded Computer Systems at the University of California at Irvine.

Frontiers of Engineering participants will hear presentations from the world's leading engineers and scientists on the topics of ID verification technologies, the engineering of complex systems, engineering for developing communities, and energy.

"Significant advances in engineering are occurring where disciplines intersect," said NAE President William A. Wulf. "Frontiers of Engineering provides an opportunity for engineers to learn about techniques and challenges in areas other than their own. This new knowledge can spark insights and collaborations that might not have occurred otherwise."

This year's symposium is sponsored by the NAE, General Electric Co., the Air Force Office of Scientific Research, the U.S. Department of Defense (DDR&E–Research), DARPA, Microsoft Corp., and Cummins Inc., as well as individual donors.

The National Academy of Engineering is an independent, nonprofit institution that serves as an adviser to government and the public on issues in engineering and technology. Its members consist of the nation's premier engineers, who are elected by their peers for their distinguished achievements. Established in 1964, NAE operates under the congressional charter granted to the National Academy of Sciences in 1863.

by Lynn Nystrom

A well-respected researcher who is now a chief of an immunology laboratory of the National Institutes of Health (NIH) has rocked the boat in the past few years for the experts in the understanding of the autoimmune system.

NIH's Polly Matzinger has developed the "danger model," suggesting that the immune system is more concerned with damage detected on the basis of a biological cell's death than with the introduction of foreign invaders, such as viruses. If Matzinger is correct, then decades of scientific and medical diagnostic thinking could be in jeopardy.

As immunologists consider the relatively new concept, a new NIH grant, awarded to Amy Bell, an electrical and computer engineer (ECE), and Karen Duca, a research assistant professor at the Virginia Bioinformatics Institute (VBI), both of Virginia Tech, could answer some of the questions about the human body's responses to viruses. Viruses cause a number of diseases, from the common cold, to herpes, to AIDS. Even some types of cancer have been linked to viruses.

Amy BellAmy Bell

Karen DucaKaren Duca

Prior to Matzinger's model, the common assumption was that the body's cells recognize substances or germs that do not come from within the body. The recognition triggers the immune system's attempt to eliminate the invader. What the immune system actually does, according to Matzinger, is discriminate between things that are dangerous and things that are not. And it does this by defining anything that does damage as dangerous. Through this selectivity process, the immune system does not respond to things that don't do damage. Examples she uses to support her thesis that the body recognizes some invading substances are not dangerous include the development of a fetus during a woman's pregnancy and the production of milk by lactating women.

So the question remains: do we really know what a body's host cell does when a virus infects it?

Bell and Duca's collaboration is an attempt to profile the host-virus system using the electrical engineering concepts of signal and image processing. As Duca, a biophysicist, introduces viruses into cells in a laboratory dish, she infects only the cell's center. Then, she and Bell, who is also currently associated with VBI as one of its faculty fellows, study the response as the virus moves outward. Their method differs from conventional laboratory studies of viruses that generally involve infecting the entire dish at once.

As the virus moves out from the center in its attempt to infect other healthy cells, Duca identifies and stains relevant markers from the virus and the host. Under ultraviolet lighting, the chemical stains become fluorescent, allowing Bell and Duca to capture images of the laboratory dish at regular time intervals as the infection progresses. The images then provide Bell and Duca with information about innate immune responses to viruses.

Using the NIH support of almost $400,000, Bell plans to next remove the noise from these low-resolution images, creating what she calls a clean immuno-fluorescent intensity signal. The noise she refers to is not audible to the human ear. From an electrical engineering standpoint, noise in this example includes the spurious artifacts that appear in the image due to the microscope’s uneven source illumination. Noise can also result from the spectral overlap of the fluorescent markers that Duca uses.

Also, since the microscope cannot capture the entire laboratory dish at once, multiple sub-images must be taken quickly, then reassembled in the proper matrix. The "montage" artifact arises from the microscope's uneven illumination, which is brighter in the center and dissipates nearer the edges of the dish for each sub-image.

To compensate for this artifact or noise, Bell's lab has developed "a method to remove the grid created by assembling the montage of sub-images. Our method--based on a model we developed that reflects the physics of fluorescent microscopy--also estimates and corrects the effect of the microscope's uneven illumination and the markers' spectral overlap," Bell explains.

As Bell and Duca are able to develop their composite images, they will be able to mathematically produce a quantitative description of the spreading of the virus as well as the host-virus interaction. "The immuno-fluorescent intensity signals (IIS) depict how the virus and host are interacting over time, from the point of origin to the point of infection," Bell says.

Ultimately, the interdisciplinary team hopes their efforts will provide a quantitative method that derives a characteristic profile or fingerprint from the IIS of any host-virus system. If their method can achieve results in hours instead of days, their techniques could be used in clinical and field settings to quickly identify known viruses, or to map unknown viruses to existing profiles to better predict their behavior and start appropriate treatment.

Ultimately, their work should contribute to what starts an immune response. And as NIH's Matzinger says, knowing what initiates an immune response will affect and, researchers hope, improve medical treatment.

Bell is an associate member of the Virginia Tech-Wake Forest University's School of Biomedical Engineering and Science (SBES). SBES research focuses on imaging and medical physics, as well as biomechanics and cell and tissue engineering. Imaging has the invaluable potential to greatly extend the reach of medical research beyond detecting the anatomical presence of the disease. Employing applied engineering technologies to treatment will allow more intensive study of diseases at the cellular level. A greater understanding of the physiology of an illness will lead to more targeted treatments.