Newest Story/Headline on Pratt Epress

Sledgehammer Saturdays May Lead to Educational Experience

admin — Fri, 20 Nov 2009 10:26:32 -0500

Pratt junior James Wu was covered in it from head to toe like a living dryer vent.

Coloradoan Hillary Cavanaugh, with slight irony, called it the best powder she’d ever seen.

Using a plastic garbage can, Kathy Kay filled an industrial dumpster with it.

The “it” is decades-old tufts of insulation ripped out of the walls and ceilings of a home in a modest neighborhood in southern Durham. Five miles away, a second group of Pratt student volunteers tore sheet rock out of a two-story home or removed anything that wasn’t nailed down in five other homes, including a wooden back deck.

More than 30 Pratt students worked a good part of a recent “Sledgehammer Saturday” preparing empty homes for renovation or relocation to a low-income neighborhood. This, and subsequent such Saturdays, may also be small steps toward a new experience for students wanting to incorporate into their education hands-on experience making existing homes greener and more energy efficient.

The Sledgehammer Saturday, as well as its November 21 sequel, was organized by Builders of Hope, a non-profit organization that renovates abandoned and boarded-up homes and makes them available for sale to low-income families. The homes are either renovated in their neighborhoods, or more likely moved to other areas to create neighborhoods of “recycled” homes. The group frequently recruits volunteer groups – like the Duke engineering students – to assist their own professionals.

While alone a worthy effort to help the community, a handful of Duke faculty members and staff saw in the activities of Builders of Hope a unique learning opportunity. Like a counterpoint to the Smart Home Program, where students designed from scratch and now tinker in a home with all the latest green technologies, working with Builders of Hope could provide students real-world experiences in sustainability and energy efficiency.

“The Smart Home is a fantastic educational facility, however it’s not like the housing most people live in,” said Pratt’s David Schaad, associate professor of the practice. “In our discussions, we quickly recognized that we really don’t have a vehicle for getting students first-hand experience in understanding how to make conventional homes more efficient. We could see for example students performing energy audits, implementing actions based on the findings, and then measuring their effectiveness.”

Discussions are ongoing between Builders of Hope, the Pratt School of Engineering and the Nicholas School of the Environment about possibly working together on a new educational experience. Those involved in these early discussions are Schaad, Jim Gaston, Smart Home Program director; and Nicholas professors Lincoln Pratson and Jonathan Weiner.

“Duke and Builders of Hope are very much interested in the possibility of collaborating in a way that provides one or more new, hands-on learning opportunities for Duke students,” Pratson said. “The volunteer weekends are an easy and immediate way to engage students in Builders of Hope projects while we pursue developing other activities in the projects with educational content.

“For example, each home Builders of Hope renovates has its own set of particular problems,” Pratson continued. “There could be a home that is a huge energy sink. It would be a great opportunity for students to figure out how the energy is being wasted and design solutions to the problem.”

After their first encounter with Duke students, Builders of Hope officials were impressed with the spirit of the volunteers.

“The students are such good workers -- they worked hard and stayed on task, just as you expect from engineers,” said Emily Egge, director of development for Builders of Hope and on-site at the insulation removal. “They worked with speed and diligence. They shifted gears without complaint – when they originally signed up it was supposed to be a more of painting and landscaping day. But, just like in most projects, things change.”

John Jenkins, Builders of Hope coordinator at the second site, added with a chuckle, “The students were great – especially when they’re tearing up stuff like sheetrock. I guess it relieves some tension. It’s funny though, they didn’t seem to go after the cleaning up with the same vigor as they went at the walls with sledgehammers.”

Diver, Chemist Joins Pratt Faculty

admin — Wed, 04 Nov 2009 09:52:13 -0500

For centuries, the forces of weather and winds have sent more than 500 ships to the bottom of the Atlantic Ocean off North Carolina’s coast. Some were also brought down by another terrifying force -- German U-boat torpedoes during the Second World War.

Forty miles off the coast from Morehead City and in more that 120 feet of water lie two particular victims of U-boat attacks that are of interest to environmental chemist and scuba diver Lee Ferguson. In a way, visiting these wrecks fulfills his main recreational and professional passions – exploring the ocean’s depths and applying his chemistry skills to better understand environmental contamination.

In early November Ferguson, a diver with more than 20 years of experience, and his graduate student Ashley Parks led a team to retrieve specially developed semipermeable membrane devices (SPMDs). These devices are designed to collect samples of oil-derived environmental contaminants that may still be released by the two wrecks into the surrounding waters. The devices had been placed by divers on his team a month earlier.

They also retrieved an SPMD that had been deployed in a ship sunk intentionally as an artificial reef off the Morehead City coast. Because that ship had been carefully scrubbed of all potential contaminants before sinking, it served as a “negative control”. The samples are now being analyzed to determine risks of toxic chemical releases from deteriorating shipwrecks.

“After all this time, there is still fuel oil in these ships,” Ferguson said. “One ship is upside down, trapping much of the oil in the hull. Over time, most the more volatile and water-soluble components have leached out, leaving behind a heavy, gooey residue. In one of the ships, I was able to use a syringe with a specially-designed needle to draw out some samples for chemical analysis.”

Ferguson’s route through his career has been circuitous, and it’s the diverse experiences he has gained personally and professionally which he believes give him a unique perspective and set of skills to apply to the field of Environmental Engineering at Duke. Earlier this summer, he joined the Pratt School of Engineering as associate professor of Civil and Environmental Engineering. He also holds a joint appointment in the Nicholas School of the Environment.

He was drawn to the study of environmental contaminants because it involves scientists of many stripes working together to solve a particular problem. Fittingly, his introduction to the Pratt community was through a seminar in the recently organized New Faculty Lecture Series, entitled “Emerging Contaminants and Interdisciplinary Research: A Chemist's Journey into Environmental Science.”

After receiving bachelors of science degrees in both chemistry and marine science from the University of South Carolina, he earned a Ph.D. in coastal oceanography from Stony Brook University.

“I started at South Carolina as a marine science major,” he recalls. “After the first year, my advisor said that if I wanted a job after I graduated, I should think hard about adding a hard science major. By my senior year, I was doing research in an environmental toxicology laboratory. I haven’t looked back”

After he completed his education and postdoctoral work, Ferguson returned to his alma mater as a faculty member in the Department of Chemistry and Biochemistry.

“Among the scientists I worked with was my former undergraduate faculty mentor, who by then was the chair of the Department of Environmental Health Sciences at South Carolina,” Ferguson said. “I spent the next six years as an assistant professor cutting my teeth in environmental chemistry while surrounded by chemists who knew a lot more than me. They really pushed me to make my science better and I learned a great deal. I feel confident that I can apply the skills and knowledge I gained to new lines of research in environmental engineering.”

When he came to Duke, Ferguson was no stranger to North Carolina; the coast of is one his favorite places to dive. Among the sites he has visited are the two known U-boats off the North Carolina coast – U-352 and U-85.

“Although I am not trained as an engineer, I am a scientist,” Ferguson said. “As such, I want to better understand both natural and engineered systems in the environment. What are the scientific principles that govern how chemicals move in the environment? As an analytical chemist, my research is driven by the desire to measure new things, in this case contaminants in the aquatic environment. With the tools I have available, I think I can add a new dimension to the study of the environmental science and engineering here at Duke.”

To help him accomplish this goal, Ferguson has just installed in his laboratory a state-of-the-art high-resolution tandem mass spectrometer. While chemists and biochemists have been using this technology for several years primarily for biomolecular and biomedical research, Ferguson plans to use it to identify and quantitatively measure what he calls emerging contaminants, or substances entering the environment that are beginning to be appreciated as potentially harmful.

“These include such compounds as bisphenol-A, certain endocrine disruptors or pharmaceuticals that are showing up in our water supply,” Ferguson said. “Our approach, using high-resolution tandem mass spectrometry to identify emerging contaminants in the aquatic environment is relatively unique within the field of environmental chemistry.”

One of the reasons Ferguson decided to join the faculty at Duke is the recent establishment of the Center for Environmental Implications of NanoTechnology (CEINT). For this effort, the National Science Foundation and the Environmental Protection Agency awarded Duke and its collaborators $14.4 million to explore the potential ecological hazards of nanoparticles.

“I spent some time with Mark Wiesner (CEINT director and Pratt professor) at a conference in Switzerland last year, and we talked at length about the center,” Ferguson said. “I was already involved in research that relates to the work being done at CEINT, and it was one of the major reasons I decided to come here. I hope I can use my expertise in environmental and analytical chemistry of nanomaterials in the environment to help them position Duke as one of the leaders in the field.”

Duke Develops Nano-Scale Drug Delivery for Chemotherapy

admin — Mon, 02 Nov 2009 10:00:29 -0500

DURHAM, N.C. -- Going smaller could bring better results, especially when it comes to cancer-fighting drugs.

Duke University bioengineers have developed a simple and inexpensive method for loading cancer drug payloads into nano-scale delivery vehicles and demonstrated in animal models that this new nanoformulation can eliminate tumors after a single treatment. After delivering the drug to the tumor, the delivery vehicle breaks down into harmless byproducts, markedly decreasing the toxicity for the recipient.

Nano-delivery systems have become increasingly attractive to researchers because of their ability to efficiently get into tumors. Since blood vessels supplying tumors are more porous, or leaky, than normal vessels, the nanoformulation can more easily enter and accumulate within tumor cells. This means that higher doses of the drug can be delivered, increasing its cancer-killing abilities while decreasing the side effects associated with systematic chemotherapy.

“When used to deliver anti-cancer medications in our models, the new formulation has a four-fold higher maximum tolerated dose than the same drug by itself, and it induced nearly complete tumor regression after one injection,” said Ashutosh Chilkoti, Theo Pilkington Professor of Biomedical Engineering at Duke’s Pratt School of Engineering. “The free drug had only a modest effect in shrinking tumors or in prolonging animal survival.”

The results of Chilkoti’s experiments were published early online in the journal Nature Materials.

“Just as importantly, we believe, is the novel method we developed to create these drugs,” Chilkoti said. “Unlike other approaches, we can produce large quantities simply and inexpensively, and we believe the new method theoretically could be used to improve the effectiveness of other existing cancer drugs.”

Central to the new method is how the drug is “attached” to its polypeptide delivery system and whether or not a drug can be dissolved in water.

The delivery system makes use of the bacterium Escherichia coli (E. coli) which has been genetically altered to produce a specific artificial polypeptide known as a chimeric polypeptide. Since E. coli are commonly used to produce proteins, it makes for a simple and reliable production plant for these specific polypeptides with high yield.

When attached to one of these chimeric polypeptides, the drug takes on characteristics that the drug alone does not possess. Most drugs do not dissolve in water, which limits their ability to be taken in by cells. But being attached to a nanoparticle makes the drug soluble.

“When these two elements are combined in a container, they spontaneously self-assemble into a water-soluble nanoparticle,” Chilkoti said. “They also self-assemble consistently and reliably in a size of 50 nanometers or so that makes them ideal for cancer therapy. Since many chemotherapeutic drugs are insoluble, we believe that this new approach could work for them as well.”

The latest experiments involved doxorubicin, a commonly used agent for the treatment of cancers of the blood, breast, ovaries and other organs. The researchers injected mice with tumors implanted under their skin with either the chimeric polypeptide-doxorubicin combination or doxorubicin alone.

The mice treated with doxorubicin alone had an average tumor size 25 times greater than those treated with the new combination. The average survival time for the doxorubicin-treated mice was 27 days, compared to more than 66 days for mice getting the new formulation.

The Duke researchers now plan to test the new combination on different types of cancer, as well as tumors growing within different organs. They will also try combining these chimeric polypeptides with other insoluble drugs and test their effectiveness against tumors.

The research was supported by the National Institutes of Health. Other Duke team members were Mingnan Chen, Jonathan McDaniel, Wenge Liu, J. Andrew Simnick, and J. Andrew MacKay, now at the University of Southern California.

Harvesting Energy from Nature’s Motions

admin — Fri, 30 Oct 2009 12:42:20 -0400

DURHAM, N.C. -- By taking advantage of the vagaries of the natural world, Duke University engineers have developed a novel approach that they believe can more efficiently harvest electricity from the motions of everyday life.

Energy harvesting is the process of converting one form of energy, such as motion, into another form of energy, in this case electricity. Strategies range from the development of massive wind farms to produce large amounts of electricity to using the vibrations of walking to power small electronic devices.

Although motion is an abundant source of energy, only limited success has been achieved because the devices used only perform well over a narrow band of frequencies. These so-called “linear” devices can work well, for example, if the character of the motion is fairly constant, such as the cadence of a person walking. However, as researchers point out, the pace of someone walking, as with all environmental sources, changes over time and can vary widely.

“The ideal device would be one that could convert a range of vibrations instead of just a narrow band,” said Samuel Stanton, graduate student in Duke’s Pratt School of Engineering, working in the laboratory of Brian Mann, assistant professor of mechanical engineering and materials sciences. The team, which included undergraduate Clark McGehee, published the results of their latest experiments in Applied Physics Letters.

“Nature doesn’t work in a single frequency, so we wanted to come up with a device that would work over a broad range of frequencies,” Stanton said. “By using magnets to ‘tune’ the bandwidth of the experimental device, we were able verify in the lab that this new non-linear approach can outperform conventional linear devices.”

Although the device they constructed looks deceptively simple, it was able to prove the team’s theories on a small scale. It is basically a small cantilever, several inches long and a quarter inch wide, with an end magnet that interacts with nearby magnets. The cantilever base itself is made of a piezoelectric material, which has the unique property of releasing electrical voltage when it is strained.

The key to the new approach involved placing moveable magnets of opposing poles on either side of the magnet at the end of the cantilever arm. By changing the distance of the moveable magnets, the researchers were able to “tune” the interactions of the system with its environment, and thus produce electricity over a broader spectrum of frequencies.

“These results suggest to us that this non-linear approach could harvest more of the frequencies from the same ambient vibrations,” Mann said. “More importantly, being able to capture more of the bandwidth makes it more likely that these types of devices could someday rival batteries as a portable power source.”

The range of applications for non-linear energy harvesters varies widely. For example, Mann is working on a project that would use the motion of ocean waves to power an array of sensors that would be carried inside ocean buoys.

“These non-linear systems are self-sustaining, so they are ideal for any electrical device that needs batteries and is in a location that is difficult to access,” Mann said.

For example, the motion of walking could provide enough electricity to power an implanted device, such as a pacemaker or cardiac defibrillator. On a larger scale, sensors in the environment or spacecraft could be powered by the everyday natural vibrations around them, Mann said.

Mann’s research is supported by the Office of Naval Research.

The Secret Behind Super Water Repellancy

admin — Mon, 26 Oct 2009 10:27:20 -0400

DURHAM, N.C. –- What do spore-launching mushrooms have in common with highly water-repellant surfaces?

According to Duke University engineers, the answer is “jumping” water droplets. As it turns out, the same phenomenon that occurs when it’s time for certain mushrooms to eject spores also occurs when dew droplets skitter across a surface that is highly water repellant, or superhydrophobic.

Using a specially designed high-speed camera and microscope set-up, the engineers for the first time captured the actions of tiny water droplets on a man-made superhydrophobic surface, and to their surprise found that the droplets literally jumped straight up and off the surface. Watch Jonathan Boreyko explain.

Simply put, when two tiny water droplets – whether on a mushroom’s spore or on a water-repellent surface – meet to form a larger drop, enough energy is released in the formation of the new droplet to cause it to “jump” off the surface.

“This spontaneous jumping is powered by the surface energy released when droplets coalesce,” said Jonathan Boreyko, a third-year graduate student at Duke’s Pratt School of Engineering, who works in the laboratory of Assistant Professor Chuan-Hua Chen. “Because this process involves very tiny droplets at high speeds, no one had captured this phenomenon before.”

The results of the team’s experiments were published in the journal Physics Review Letters.

“A similar phenomenon occurs with the ejection of spores, known as ballistospores, from certain kinds of mushrooms,” Boreyko said. “When a drop of water condensate at the base of the spore comes into contact with the wetted spore, it triggers the propulsion of the spore into the air.”

Chen and Boreyko’s research is the first known engineering reproduction of the ballistospore ejection process.

The work also has immediate applications in energy harvesting and thermal management, Chen said. For example, the spontaneous jumping motion offers an internal mechanism, independent of gravity, to remove condensate from the condensers in power plants.

The superhydrophobic surface used by the researchers is characterized by rows and rows of tiny bumps, covered with even tinier hairs projecting upward. When a water droplet lands on this type of surface, it only touches the ends of the tiny hairs. This creates pockets of air underneath the droplet that keeps it from touching the surface. This cushion of air keeping the droplet aloft is much like a puck in an air-hockey game. The same principle allows water striders to skim along the surface of ponds without falling into the water, Chen said.

“When two of these condensate drops coalesce into one, they jump at very high speeds,” Boreyko said. “They move as fast as one meter per second. By taking a side view of the phenomenon, we can plainly see the droplets jump. You wouldn’t see it looking down on the surface.”

Interestingly, the researchers found that the mechanism used to eject ballistospores is almost identical. The critical size of the droplet on the spore for the jumping to occur is the same as that on the man-made superhydrophobic surface, and spores “jump” off the mushroom at about the same speed.

Chen said knowing how superhydrophobic surfaces are able to repel condensate drops could lead to improvements in many types of systems where heat needs to be removed through condensation.

“Smaller water droplets are much more efficient at transferring heat,” Chen explained. “With the jumping mechanism, the average droplet size is about one hundred times smaller.

“In conventional cooling systems, as in big industrial plants, condensate must be removed using external forces for continuous operation,” Chen said. “One of the main benefits of this superhydrophobic surface is that it needs no external energy – the coalescing of the droplets provides all the energy needed to remove the condensate.”

Chen’s research is supported by the National Science Foundation. Jonathan Boreyko is supported by the Pratt-Gardner Fellowship.

Unsticking the Sticky: The Lotus’s Clever Way of Staying Dry

admin — Thu, 22 Oct 2009 09:29:12 -0400

DURHAM, N.C. –- An ancient Confucian philosopher once said, “I love the lotus because while growing from mud, it is unstained.”

Now, almost one thousand years since Zhou Dunyi wrote these lines in China, scientists finally understand how the plant keeps itself clean and dry. It took an ultra high speed camera, a powerful microscope and an audio speaker to unlock a secret that has puzzled scientists for ages.

The process of solving this biological problem inspired Duke University engineers to make use of man-made surfaces resembling the lotus to improve the efficiency of modern engineering systems, such as power plants or electronic equipment, which must be cooled by removing heat through water evaporation and condensation.

For the first time, scientists were able to observe water as it condensed on the leaf’s surface, and more importantly, how the water condensate left the leaf.

The trick lies in the surface of the plant’s large leaves, and the subtle vibrations of nature. The leaves are covered with tiny irregular bumps spiked with even tinier hairs projecting upward. When a water droplet lands on this type of surface, it only touches the ends of the tiny hairs. The droplet is buoyed by air pockets below and ultimately is repelled off the leaf.

“We faced a tricky problem – water droplets that fall on the leaf easily roll off, while condensate that grows from within the leaf’s nooks and crannies is sticky and remains trapped,” said Jonathan Boreyko, a third-year graduate student at Duke’s Pratt School of Engineering, who works in the laboratory of assistant professor Chuan-Hua Chen. The results of the team’s experiments were published in the journal Physics Review Letters. Watch Boreyko explain phenomenon.

“Scientists and engineers have long wondered how these sticky drops are eventually repelled from the leaf after their impalement into the tiny projections,” Boreyko said. “After bringing lotus leaves into the lab and watching the condensation as it formed, we were able to see how the sticky drops became unsticky.”

The key was videotaping the process while the lotus leaf rested on top of the woofer portion of a stereo speaker at low frequency. Condensation was created by cooling the leaf. It turned out that after being gently vibrated for a fraction of a second, the sticky droplets gradually unstuck themselves and jumped off the leaf.

Voila, a dry leaf.

“This solves a long-standing puzzle in the field,” Chen said. “People have observed that condensation forms every night on the lotus leaf. When they come back in the morning the water is gone and the leaf is dry. The speaker reproduced in the lab what happens every day in nature, which is full of subtle vibrations, especially for the lotus, which has large leaves atop long and slender stems.”

The results of these experiments, as well as earlier ones showing for the first time that water droplets spontaneously “jump” off a highly water-repellent, or superhydrophobic, surface, will allow engineers to employ man-made surfaces much like the lotus leaf in settings where the removal of condensation and the transfer of heat are necessary.

"We have revealed the physics behind anti-dew superhydrophobicity, a vital property for water-repellent materials to be deployed in the real world,” Chen said. “These materials will be used in humid or cold environments where condensation will naturally occur. Our findings point to a new direction to develop water-repellent materials that would survive in demanding natural environments, and have strong implications for a variety of engineering applications including non-sticking textiles, self-cleaning optics and drag-reducing hulls.”

Chen’s research is supported by Pratt startup funds.

New Strategy for Mending Broken Hearts?

admin — Mon, 12 Oct 2009 15:34:12 -0400

DURHAM, N.C. -- By mimicking the way embryonic stem cells develop into heart muscle in a lab, Duke University bioengineers believe they have taken an important first step toward growing a living “heart patch” to repair heart tissue damaged by disease.

In a series of experiments using mouse embryonic stem cells, the bioengineers used a novel mold of their own design to fashion a three-dimensional “patch” made up of heart muscle cells, known as cardiomyocytes. The new tissue exhibited the two most important attributes of heart muscle cells -– the ability to contract and to conduct electrical impulses. The mold looks much like a piece of Chex cereal in which researchers varied the shape and length of the pores to control the direction and orientation of the growing cells.

The researchers grew the cells in an environment much like that found in natural tissues. They encapsulated the cells within a gel composed of the blood-clotting protein fibrin, which provided mechanical support to the cells, allowing them to form a three-dimensional structure. They also found that the cardiomyocytes flourished only in the presence of a class of “helper” cells known as cardiac fibroblasts, which comprise as much as 60 percent of all cells present in a human heart.

“If you tried to grow cardiomyocytes alone, they develop into an unorganized ball of cells,” said Brian Liau, graduate student in biomedical engineering at Duke’s Pratt School of Engineering. Liau, who works in the laboratory of assistant professor Nenad Bursac, presented the results of his latest experiments during the annual scientific sessions of the Biomedical Engineering Society in Pittsburgh.

“We found that adding cardiac fibroblasts to the growing cardiomyocytes created a nourishing environment that stimulated the cells to grow as if they were in a developing heart,” Liau said. “When we tested the patch, we found that because the cells aligned themselves in the same direction, they were able to contract like native cells. They were also able to carry the electrical signals that make cardiomyocytes function in a coordinated fashion.”

“The addition of fibroblasts in our experiments provided signals that we believe are present in a developing embryo,” Liau said. The need for helper cells is not uncommon in mammalian development. For example, he explained, nerve cells need “sheathe” cells known as glia in order to develop and function properly.

Bursac believes that the latest experiments represent a proof-of-principle advance, but said there are still many hurdles to overcome before such patches could be implanted into humans with heart disease.

“While we were able to grow heart muscle cells that were able to contract with strength and carry electric impulses quickly, there are many other factors that need to be considered,” Bursac said. “The use of fibrin as a structural material allowed us to grow thicker, three-dimensional patches, which would be essential for the delivery of therapeutic doses of cells. One of the major challenges then would be establishing a blood vessel supply to sustain the patch.”

The researchers plan to test their model using non-embryonic stem cells. For use in humans, this is important for many reasons, both scientifically and ethically, Bursac said. Recent studies have demonstrated that some cells from human adults have the ability to be reprogrammed to become similar to embryonic stem cells.

“Human cardiomyocytes tend to grow a lot slower than those of mice,” Bursac said. “Since it takes nine months for the human heart to complete development, we need to find a way to get the cells to grow faster while maintaining the same essential properties of native cells.”

If they could use a patient’s own cells, the patch would also evade an immune system reaction, Bursac added.

The research was supported by National Institutes of Health, the National Heart Lung Blood Institute and Duke’s Stem Cell Innovation program. Other Duke members of the research team were Weining Bian and Nicolas Christoforou.

Understanding a Cell's Split Personality Aids Synthetic Circuits

admin — Mon, 05 Oct 2009 10:25:05 -0400

DURHAM, N.C. -- As scientists work toward making genetically altered bacteria create living “circuits” to produce a myriad of useful proteins and chemicals, they have logically assumed that the single-celled organisms would always respond to an external command in the same way.

Alas, some bacteria apparently have an individualistic streak that makes them zig when the others zag.

A new set of experiments by Duke University bioengineers has uncovered the existence of “bistability,” in which an individual cell has the potential to live in either of two states, depending on which state it was in when stimulated.

Taking into account the effects of this phenomenon should greatly enhance the future efficiency of synthetic circuits, said biomedical engineer Lingchong You of Duke’s Pratt School of Engineering and the Duke Institute for Genome Sciences & Policy.

In principle, re-programmed bacteria in a synthetic circuit can be useful for producing proteins, enzymes or chemicals in a coordinated way, or even delivering different types of drugs or selectively killing cancer cells, the scientists said.

Researchers in this new field of synthetic biology “program” populations of genetically altered bacteria to direct their actions in much the same way that a computer program directs a computer. In this analogy, the genetic alteration is the software, the cell the computer. The Duke researchers found that not only does the software drive the computer’s actions, but the computer in turn influences the running of the software.

“In the past, synthetic biologists have often assumed that the components of the circuit would act in a predictable fashion every time and that the cells carrying the circuit would just serve as a passive reactor,” You said. “In essence, they have taken a circuit-centric view for the design and optimization process. This notion is helpful in making the design process more convenient.”

But it's not that simple, say You and his graduate student Cheemeng Tan, who published the results of their latest experiments early online in the journal Nature Chemical Biology.

“We found that there can be unintended consequences that haven’t been appreciated before,” said You. “In a population of identical cells, some can act one way while others act in another. However, this process appears to occur in a predictable manner, which allows us to take into account this effect when we design circuits.”

Bistability is not unique to biology. In electrical engineering, for example, bistability describes the functioning of a toggle switch, a hinged switch that can assume either one of two positions – on or off.

“The prevailing wisdom underestimated the complexity of these synthetic circuits by assuming that the genetic changes would not affect the operation of the cell itself, as if the cell were a passive chassis,” said Tan. “The expression of the genetic alteration can drastically impact the cell, and therefore the circuit.

“We now know that when the circuit is activated, it affects the cell, which in turn acts as an additional feedback loop influencing the circuit,” Tan said. “The consequences of this interplay have been theorized but not demonstrated experimentally.”

The scientists conducted their experiments using a genetically altered colony of the bacteria Escherichia coli (E.coli) in a simple synthetic circuit. When the colony of bacteria was stimulated by external cues, some of the cells went to the “on” position and grew more slowly, while the rest went to the “off” position and grew faster.

“It is as if the colony received the command not to expand too fast when the circuit is on,” Tan explained. “Now that we know that this occurs, we used computer modeling to predict how many of the cells will go to the ‘on’ or ‘off’ state, which turns out to be consistent with experimental measurements”

The experiments were supported by the National Science Foundation, the National Institutes of Health and a David and Lucille Packard Fellowship. Duke’s Philippe Marguet was also a member of the research team.

DARPA-Funded Duke Study to Detect Viral Infection Before Symptoms Appear

admin — Mon, 28 Sep 2009 09:24:41 -0400

The Defense Advanced Research Projects Agency (DARPA), the research arm of the U.S. Department of Defense, has awarded Duke University $19.5 million for an effort led by the Duke Institute for Genome Sciences & Policy (IGSP) to design a portable, easy-to-use diagnostic device that can reveal who is infected with an upper respiratory virus before the first cough or sneeze.

DARPA is interested in such a device because it could offer military commanders in the field valuable information about which soldiers are likely to become sick and potentially unfit for duty.

The project, under the direction of Geoffrey Ginsburg, MD, PhD, director of the IGSP's Center for Genomic Medicine, is being conducted by a broad and experienced team of investigators including Christopher Woods, MD, MPH; and Aimee Zaas, MD, MPH, from Duke's Division of Infectious Disease; Lawrence Carin, PhD, from Duke's Pratt School of Engineering; and Alfred Hero, PhD, from the University of Michigan's College of Engineering.

Using advanced genomic and statistical tools, investigators have already made considerable progress.

In the first phase of the project, researchers discovered a genomic "signature" of infection -- a set of changes in gene expression that occurred in people who became symptomatic after exposure to a rhinovirus, the influenza A virus, or the respiratory syncytial virus.

They found that in some cases, those changes became apparent hours or even days before symptoms arose.

Biomedical engineers in Duke's Pratt School of Engineering have already designed a prototype of the device that can "read" the genomic signatures of infection.

Over the next two years, in the second phase of the study, researchers will refine the probe and further validate the genomic signature of infections by additional pathogens, including the seasonal H1N1 virus.

Some of those studies will include human viral challenge studies already underway at Retroscreen Virology, Ltd., in London, U.K. Other viral challenge studies are contemplated later in the program in the United States.

One aspect of the research focuses on the natural history of viral infections among college students living in close quarters.

This fall, investigators are enrolling Duke students in freshman dormitories in a study of the onset and spread of upper respiratory infections, including influenza. Participants will use a special website to file daily reports about their health and provide blood and other specimens as needed.

Investigators hope to enroll from 500 to 800 students and follow them for the entire academic year.

"We expect to gather valuable data about the novel H1N1 virus from these studies," says Ginsburg. "Presymptomatic detection of a cold or flu would be a significant advance in maintaining the health of our troops and will certainly be a breakthrough for the public's health and well being, as well."

Collaborators in the project include researchers at the University of Wisconsin, the University of Virginia, and the National Center for Genome Resources in New Mexico.

Room’s Ambience Fingerprinted By Cell Phone

admin — Thu, 24 Sep 2009 09:19:25 -0400

DURHAM, N.C. -- Your smart phone may soon be able to know not only that you're at the mall, but whether you're in the jewelry store or the shoe store.

Duke University computer engineers have made use of standard cell phone features – accelerometers, cameras and microphones – to turn the unique properties of a particular space into a distinct fingerprint. While standard global positioning systems (GPS) are only accurate to 10 meters (32 feet) and do not work indoors, the new application is designed to work indoors and can be as precise as telling if a user is on one side of an interior wall or another.

The system, dubbed SurroundSense, uses the phone’s built-in camera and microphone to record sound, light and colors, while the accelerometer records movement patterns of the phone’s user. This information is sent to a server, which knits the disparate information together into a single fingerprint.

“You can’t tell much from any of the measurements individually, but when combined, the optical, acoustic and motion information creates a unique fingerprint of the space,” said Ionut Constandache, graduate student in computer science. He presented the details of SurroundSense at the 15th International Conference on Mobile Computing and Networking in Bejing.

For example, in a bar, people spend little time moving and most time sitting, while the room is typically dark and noisy. In contrast, a Target store will be brightly lit with vibrant colors – especially red – with movement up and down aisles. SurroundSense can tell these differences.

Students of Romit Roy Chouhury, Duke assistant professor of electrical and computer engineering and senior member of the research team, fanned out across Durham, N.C. with their cell phones, collecting data in different types of businesses. So that they would not bias the measurements, the students “mirrored” the actions of selected customers.

“We went to 51 different stores and found that SurroundSense achieved an average accuracy of about 87 percent when all of the sensing capabilities were used,” Constandache said.

As more people use the application, it gets “smarter.”

“As the system collects and analyzes more and more information about a particular site, the fingerprint becomes that much more precise,” said Roy Choudhury. “Not only is the ambience different at different locations, but also can be different at different times at the same location."

SurroundSense collects data at different time points, so it would be able to distinguish a Starbucks store at the morning rush when there are many customers from the slower period in mid-afternoon.

“We believe that SurroundSense is an early step toward a long-standing challenge of improving indoor localization,” Roy Choudhury said.

Currently, in order for the phone to collect data, it must be held with the camera facing down, though the researchers are working on strategies for the application to work if the phone is in a pocket, case or handbag. However, as the researchers pointed out, phones are now coming onto the market that are worn on the wrist or around the neck on a necklace.

As in many technical advances, it appears that batteries can be an Achilles' heel. The Duke researchers are now considering the tradeoffs between having the application “on” all the time, which drains the battery faster, or having it take measurements at regular intervals. They are also trying to determine whether the entire application should be housed on the server, the phone, or some combination of the two.

Roy Choudhury’s research is supported by the National Science Foundation, Nokia, Verizon and Microsoft Research. Duke undergraduate Martin Azizyan also participated in the project.

headliners

admin — Tue, 15 Sep 2009 09:00:44 -0400

When Nano May Not Be Nano

admin — Mon, 14 Sep 2009 10:36:35 -0400

DURHAM, N.C. – The same properties of nanoparticles that make them so appealing to manufacturers may also have negative effects on the environment and human health.

However, little is known which particles may be harmful. Part of the problem is determining exactly what a nanoparticle is.

A new analysis by an international team of researchers from the Center for the Environmental Implications of NanoTechnology (CEINT), based at Duke University, argues for a new look at the way nanoparticles are selected when studying the potential impacts on human health and the environment. They have found that while many small particles are considered to be "nano," these materials often do not meet full definition of having special properties that make them different from conventional materials.

Under the prevailing definition, a particle is deemed nano if its diameter is between 1 and 100 nanometers (nm) – about 1/10,000 the diameter of a human hair – and if it has properties that significantly differ from its naturally occurring, or bulk, counterpart.

The special properties of nanoparticles come from their high surface-area-to-volume ratio. They also have a considerably higher percentage of atoms on their surface compared to bulk particles, which can make them more reactive. These man-made materials can be found in a vast array of consumer products, including paints and sunscreens, as well as in water treatment plants and drug delivery systems.

For most of this decade, discussions of nanoparticles have tended to focus more on their size than their properties. However, after reviewing the scientific literature, the Duke-led team believes that the old definition is not specific enough. A definition that focuses on properties is critical, they say, to help scientists determine which particular nanoparticles are the most likely to represent a threat to the environment or human health.

Generally speaking, it is the very smallest particles (less than 30 nanometers) that should receive the most attention in studying the environmental and human health impacts of nanomaterials, according to Mark Wiesner, a Duke professor of civil and environmental engineering and director of the federally funded CEINT.

“There are an infinite number of potential new man-made nanoparticles, so we need to find a way to narrow our efforts to those that have the greatest likelihood of having the unique properties with unique effects,” Wiesner said.

“A key question to be answered is whether or not a particular nanoparticle has toxic or hazardous properties that are truly different from identical particles in their bulk form,” Wiesner continued. “This question has not been answered. To do so, we need to be speaking the same language when assessing any unique properties of these novel materials.”

The results of Wiesner’s analysis were published in the journal Nature Nanotechnology. The study was supported by CEINT, which is jointly funded by the National Science Foundation and Environmental Protection Agency.

Specifically, the researchers found that nanoparticles approaching the 100 nm end of the size spectrum tend to have fewer special properties when compared to their bulk counterparts. Furthermore, they found that nanoparticles smaller than 30 nm tend to exhibit the unique properties that should command increased scrutiny, Wiesner said.

“Many nanoparticles smaller than 30 nanometers undergo drastic changes in their crystalline structure that enhance how the atoms on their surface interact with the environment,” Wiesner said.

For example, because of the increased surface-area-to-volume ratio, nanoparticles can be highly reactive with other chemicals in the environment and can also disrupt certain activities within cells.

“While there have been reports of nanoparticle toxicity increasing as the size decreases, it is still uncertain whether this increase in reactivity is harmful to the environment or human safety,” Wiesner said. “To settle this issue, toxicological studies should contrast particles that exhibit novel size-dependant properties, particularly concerning their surface reactivity, and those particles that do not exhibit these properties.”

Other members of the research team include Melanie Auffan, Duke; Jerome Rose and Jean-Yves Bottero, Aix-Marseille Universite, France; Gregory Lowry, Carnegie Mellon University; and Jean-Pierre Jolivet, Laboratoire de Chimie de la Matiere Condensee de Paris, France.

Smart Home Recognized for Innovations

admin — Fri, 11 Sep 2009 14:11:56 -0400

Once again, the Smart Home Program has received national attention for its contributions to making the world a greener place.

This time, it was the U.S. Green Building Council (USGBC), who recently cited the Duke program as one of the recipients of its Excellence in Green Building Curriculum Recognition Awards for 2009.

Duke’s Smart Home Program was one of five award winners in the category covering colleges and universities. The award recognizes innovative green building curricula at all levels of education and provides financial support for promising new programs

“The Duke Smart Home Program continues to grow and attract students interested in smart technology and sustainable lifestyles,” said Jim Gaston, Duke Smart Home Program director. “It is exciting to see students connect with industry and the community to develop innovative solutions that utilize new technologies. This award for excellence by the USGBC confirms that Duke is at the forefront of the green movement.”

Now in its second year, the USGBC initiative is a central component of its commitment to identify and disseminate innovative green building curricula to educators across the country.

“Through this initiative, USGBC is recognizing those organizations that are taking the lead in the development of innovative green building knowledge and resources,” said Rebecca Flora, USGBC senior vice president for education & research. “The extraordinary rise in green building in recent years has accelerated the need for relevant and engaging educational programs, and all of our participating organizations are playing an active role in helping USGBC meet this important need.”

Recognition Awards honor existing green building education projects, activities or programs, and includes a $1,000 honorarium

The centerpiece of Duke’s program is the Home Depot Smart Home, which is a 10-person student residence hall for green living and learning. Completed in 2007, the home is the world's first LEED Platinum live-in laboratory. Students can participate in the program in a variety of ways: independent study for credit, house courses focused on sustainability topics, as senior capstone design projects, and as members of the Smart Home student club.

Primarily focused on undergraduates, the program encourages students from different academic disciplines to form teams and explore ways to use technology in the home. Smart Home Project students are encouraged to explore new technologies that aren't being addressed through commercially available technology.

The USGBC awards were judged on demonstrated success, ability to be replicated, the scope of influence, advancement of green principles within the educational community and the fostering of a collaborative or interdisciplinary approach. The USGBC is made up of 78 local affiliates, more than 20,000 member companies and organizations, and more than 131,000 LEED accredited professionals.

Buildings in the U.S. are responsible for 39 percent of CO2 emissions, 40 percent of energy consumption, 13 percent of water consumption and 15 percent of GDP per year, according to the USGBC, which means that greater building efficiency can meet 85 percent of future U.S. demand for energy, and a national commitment to green building has the potential to generate 2.5 million American jobs.

Back in the Bicycle Seat Again

admin — Fri, 11 Sep 2009 09:04:55 -0400

For Claude Flynn, long bicycle rides in the fresh air were therapy for the mind and exercise for the body. Every Sunday, she’d ride her bike 35 to 40 miles through the rolling Chatham County countryside south of Chapel Hill, N.C. Often, she would stop in a meadow, take in the sun, listen to the birds singing and enjoy a sandwich and bottled water.

That all changed in 2003, when a car accident left her unable to flex her left knee enough to the pedal a bicycle.

“Since the accident, I haven’t ridden my bike at all,” said Flynn, 59, an occupational therapist assistant who hails from France. “I had assumed that I wouldn’t ever be able to ride again.”

However, the ingenuity of three recently graduated Pratt School of Engineering undergrads put Flynn once again behind the handlebars.

“I’ve gotten up to about 15 miles, which is pretty good,” she said. “I might try to work my way back up to 35 miles, but I don’t have to do 35 to be happy. I’m just so excited to be riding again.”

Watch her ride (movie goes here, awaiting URL)

The students – Stephanie Tupi, Winston Lynk and Megan Toney – devised and built a modified crank arm – the metal part of the bike that “holds” the pedal itself on one end and attaches to the main gear on the other. By altering the left crank arm, they were able to compensate for her inability to completely extend her left leg.

“We came up with a pivoting left crank arm that allows the pedal to drop to a lower height at the peak of the pedal motion,” explained Lynk, a BME graduate (’09) from Coral Gables, Fla. “This decreased the degree of knee flexion she needed for pedaling.”

The story begins in BME 260: Devices for People with Disabilities, a course taught every year by Larry Bohs, assistant research professor in biomedical engineering. Now in its 12th year, the semester-long course matches small groups of students with a specific problem hindering the quality of life of a real person. Each team’s mission is to conceive, design and manufacture a solution.

The first thing the team did when they settled on their project was to visit Flynn at her Chapel Hill home.

“They asked a lot questions and made measurements of my knee and its capability to move,” Flynn recalls. “Throughout the whole process, there were many phone calls, e-mails and visits to my house. I was very impressed by their determination to make sure I got what I needed. They were very considerate and involved in the process. It was quite touching seeing three kids being so very thorough making sure to get everything right.”

By the end of the semester, the device was complete. The team took it to Flynn’s house and installed it on her bike.

“She kept going around circles in a parking lot, and we couldn’t get her off,” said Toney, a BME graduate from Wrentham, Mass.

This summer, the team entered their invention into the annual competition held by the Rehabilitation and Assistive Technology Society of North America (RESNA). Out of more than 60 teams from across the country, the Duke team was honored as one the top five during a ceremony in New Orleans. Teams from Northeastern, Georgia Tech, University of North Carolina and Rice were the other winning teams.

For team members, the experience of developing a device, and then completing all the work that goes into preparing the presentation for the competition, reinforced the choices they made for their future endeavors.

“I am considering working in product development and design, and after this experience, my decision was solidified,” Lynk said. “What exactly I want to build I’m not sure yet, but I know I want to make things that can help people.”

Toney echoed her classmate’s sentiments.

“This class helped me to decide on a career working in assistive engineering,” Toney said. “I like helping people, not just sitting in an office all day. Ultimately I’d like to develop prosthetic devices that will improve someone’s quality of life.”

Bohs said that his class is unique from most in that students not only get hands-on practical experience, but they also have the opportunity to work and interact with the real person who will use their device. In the process, he said, they learn about tools, materials, how to use their hands and machine tools in the course of a semester.

Over the years, Bohs has made contacts with patients, therapists and teachers who provide him with ideas for individuals that could use his class’s help. After a vigorous screening process, he selects those challenges that offer the most potential help for the client, as well as those offering a unique learning experience for his students.

“It’s important to not only give the students a challenging project, but also one that by the end of the semester they can feel a true sense of accomplishment,” Bohs said. “For me, I get satisfaction knowing we are doing something for someone that makes a difference, while hopefully awakening some new interests in the students.”

For Flynn, the students’ efforts truly have improved her quality of life.

“Biking had always been such an important part of my life, both physically and spiritually,” she said. “It was very frustrating not being able to ride. I did take up swimming, and while I enjoyed it, it just wasn’t the same. Being outdoors in nature is such a totally different experience.”

Back in the Bicycle Seat Again

admin — Tue, 08 Sep 2009 12:31:09 -0400

For Claude Flynn, long bicycle rides in the fresh air were therapy
for the mind and exercise for the body. Every Sunday, she’d ride her
bike 35 to 40 miles through the rolling Chatham County countryside
south of Chapel Hill, N.C. Often, she would stop in a meadow, take in
the sun, listen to the birds singing and enjoy a sandwich and bottled
water.

That all changed in 2003, when a car accident left her unable to flex her left knee enough to the pedal a bicycle.

“Since the accident, I haven’t ridden my bike at all,” said Flynn, 59,
an occupational therapist assistant who hails from France. “I had
assumed that I wouldn’t ever be able to ride again.”

However, the ingenuity of three recently graduated Pratt School of
Engineering undergrads put Flynn once again behind the handlebars.

“I’ve gotten up to about 15 miles, which is pretty good,” she said. “I
might try to work my way back up to 35 miles, but I don’t have to do 35
to be happy. I’m just so excited to be riding again.”

The students – Stephanie Tupi, Winston Lynk and Megan Toney –
devised and built a modified crank arm – the metal part of the bike
that “holds” the pedal itself on one end and attaches to the main gear
on the other. By altering the left crank arm, they were able to
compensate for her inability to completely extend her left leg.

“We came up with a pivoting left crank arm that allows the pedal to
drop to a lower height at the peak of the pedal motion,” explained
Lynk, a BME graduate (’09) from Coral Gables, Fla. “This decreased the
degree of knee flexion she needed for pedaling.”

The story begins in BME 260: Devices for People with Disabilities, a
course taught every year by Larry Bohs, assistant research professor in
biomedical engineering. Now in its 12th year, the semester-long course
matches small groups of students with a specific problem hindering the
quality of life of a real person. Each team’s mission is to conceive,
design and manufacture a solution.

The first thing the team did when they settled on their project was to visit Flynn at her Chapel Hill home.

“They asked a lot questions and made measurements of my knee and its
capability to move,” Flynn recalls. “Throughout the whole process,
there were many phone calls, e-mails and visits to my house. I was very
impressed by their determination to make sure I got what I needed. They
were very considerate and involved in the process. It was quite
touching seeing three kids being so very thorough making sure to get
everything right.”

By the end of the semester, the device was complete. The team took it to Flynn’s house and installed it on her bike.

“She kept going around in circles in a parking lot, and we couldn’t get her off,” said Toney, a BME graduate from Wrentham, Mass.

This summer, the team entered their invention into the annual
competition held by the Rehabilitation and Assistive Technology Society
of North America (RESNA). Out of more than 60 teams from across the
country, the Duke team was honored as one the top five during a
ceremony in New Orleans. Teams from Northeastern, Georgia Tech,
University of North Carolina and Rice were the other winning teams.

For team members, the experience of developing a device, and then
completing all the work that goes into preparing the presentation for
the competition, reinforced the choices they made for their future
endeavors.

“I am considering working in product development and design, and after
this experience, my decision was solidified,” Lynk said. “What exactly
I want to build I’m not sure yet, but I know I want to make things that
can help people.”

Toney echoed her classmate’s sentiments.

“This class helped me to decide on a career working in assistive
engineering,” Toney said. “I like helping people, not just sitting in
an office all day. Ultimately I’d like to develop prosthetic devices
that will improve someone’s quality of life.”

Bohs said that his class is unique from most in that students not only
get hands-on practical experience, but they also have the opportunity
to work and interact with the real person who will use their device. In
the process, he said, they learn about tools, materials, how to use
their hands and machine tools in the course of a semester.

Over the years, Bohs has made contacts with patients, therapists and
teachers who provide him with ideas for individuals that could use his
class’s help. After a vigorous screening process, he selects those
challenges that offer the most potential help for the client, as well
as those offering a unique learning experience for his students.

“It’s important to not only give the students a challenging project,
but also one that by the end of the semester they can feel a true sense
of accomplishment,” Bohs said. “For me, I get satisfaction knowing we
are doing something for someone that makes a difference, while
hopefully awakening some new interests in the students.”

For Flynn, the students’ efforts truly have improved her quality of life.

“Biking had always been such an important part of my life, both
physically and spiritually,” she said. “It was very frustrating not
being able to ride. I did take up swimming, and while I enjoyed it, it
just wasn’t the same. Being outdoors in nature is such a totally
different experience.”

Medical Device Internship Inspires Pleatman

admin — Wed, 02 Sep 2009 10:37:17 -0400

What do you get when you put 28 college students from across the nation into the same apartment complex in Cincinnati, Ohio? An amazing summer internship experience with a Johnson & Johnson company called Ethicon Endo-Surgery.

Alaina Pleatman, a member of Duke’s class of 2010 and a biomedical engineering major, is one of the students selected for the summer internship in Ethicon Endo-Surgery’s Research and Development Department.

Ethicon Endo-Surgery is a medical device company that focuses on creating products for minimally invasive endoscopic surgery, a modern alternative for traditional operations that are usually more traumatic and painful. Pleatman is working on several complex projects aimed at enhancing medical surgery practices.

In the first of two projects Pleatman is working on, she is part of a team that is working on developing a new device for minimally invasive surgery. By speaking to various surgeons and gathering information such as how different types of procedures can be improved, the team is analyzing the risks of entering this new market.

“The ultimate goal is for the new device is to help make operations faster with less bleeding to decrease the recovery time for the patient,” she said. Pleatman has been helping to develop a piece of equipment that will be used to test the device presently used by surgeons against the new one that is in the works.

Her second, more hands-on project has her helping with is the design of a blade for an electrosurgical device used for cutting and coagulating blood vessels. This is where her engineering background comes into play. To test the functionality of the blade, she drew free body diagrams to analyze the stresses that it will see and also developed prototypes using CAD (Computer-Aided Design) software.

This sounds like a serious, complex job for a mere college student, but Pleatman assures that her educational skills have been put to good use. “Duke prepared me well. Since I’m majoring in biomedical engineering, I have taken a lot of classes that allow me to apply class knowledge to my work here.”

Her bio focus has paid off as well, Pleatman explains. “Since I work mostly with mechanical engineers here, as a BME major I’ve been able to help with the biological aspect of the job that the mechanical engineers don’t know, such as tissue identification and composition,” she said.

The internship has exposed her to many facets of the medical device market. She better understand that in order to pursue an engineering career with a company such as Ethicon, she needs to develop a good foundation in mechanical engineering design principles. This is something she is more open to after her experience as an intern.

She has also been inspired to explore the marketing side of the company. Seeing what the marketing people has been interesting, and Pleatman is now entertaining the thought of getting an MBA, although her future plans aren’t set just yet. She has plans to interview in the fall for an engineering position at a medical device company, is considering Pratt’s 4+1 program to obtain her masters. She is also considering healthcare consulting as well as graduate school.

Pleatman is a native of West Bloomfield, MI and the president of the Society of Women Engineers here at Duke.

Learns Insider Secrets of Pharmaceutical Biz

admin — Thu, 27 Aug 2009 11:09:12 -0400

Brianna Vey, a rising senior and a biomedical engineering major, is spending her summer far from her hometown of Raleigh, North Carolina. Temporarily at home in Philadelphia, the famed “City of Brotherly Love,” Vey is interning at Accenture, a consulting firm specializing in information technology consulting, and learning what it takes to operate an organized company.

“I’m working with performance data analysis right now, and trying to figure out the best ways to work with the data, present it, and make up reports,” Vey explains.

Accenture is currently working a project with a global pharmaceutical company, and Vey is helping out on the database management incentive. This is Vey’s first exposure to the data management world. This is a seemingly unusual concentration for a biomedical engineering major, but it’s something she has taken a great liking to.

“The reason someone with a BME degree would join Accenture isn't perhaps to do this work—reports and analysis duties, specifically, but to be in Accenture to meet and work with a variety of health and pharmaceutical companies in the span of one job,” she explains.

She’s quick to mention that her experience and skills with computer design proved to be an advantage for report writing as well.

“The database management is for clinical trial data, specifically,” Vey explains. “For example, they have to put a new drug through testing and Accenture is making a database that can make the trial time for the drug shorter, which is beneficial for the company because it gives them a more competitive edge if they can get their drug out on the market sooner than other companies.”

Accenture’s goal is to improve the efficiency and organization of various drug and medical companies. So it goes without saying that consulting company itself needs to be very organized, and Vey is involved in the process for this goal as well, compiling the company’s various databases into a larger, more accessible one.

Vey is excited to contribute to the company’s business objective. “Eventually, we’re going to combine all databases and move all of our reports so we only have to maintain one database. This will make it so the information is more valid and a lot more accurate… making things go smoothly all around” she says.

Vey said she was well prepared to take on this job, and notes that her education at Duke has been on target. “The Duke curriculum helped a lot” she says, and because of her demanding schedule at school, she’s learned to juggle many tasks at once with ease. “The school puts a lot of pressure on you. You’re trying to do six activities all at once within a short amount of time—Accenture is a lot like that, and I’ve really learned about time management.”

Vey heard about the internship first through word of mouth and then was able to apply for it through Duke’s eRecruiting online job resource. “I talked with people that were already in the intern program, people that were full time employees after interning, and anyone that would talk to me about Accenture and what it was like to work there. Aside from putting a lot of time into interview preparation and research, I think extensive networking helped me get a spot.”

Mystery Shopping Across Generations

admin — Mon, 24 Aug 2009 13:09:52 -0400

Jamie Heller, a rising junior and mechanical engineer here at Duke, is getting a taste of office life this summer. He is currently working as an intern at Wilkinson Real Estate Advisors in Atlanta. Heller heard about the internship through the Pratt career advisers, and decided to take a chance on a career experience outside of the engineering field.

Heller turns out to be lucky twice over. He gets to stay close to his hometown interning for Wilkinson’s offices in Atlanta, and he also works under the direction of a former Pratt alumnus, Jerry Wilkinson, who graduated with an electrical engineering degree. Heller says he is fortunate to work under Wilkinson because Jerry showed him that engineers are versatile in the job market.

Ironically, although he intended to have a non-engineering experience, Heller said he has learned a lot about the value of engineering as a career. “Engineering is putting in the hours and doing the hard work, and if you like it enough, go into that.”

But perhaps more importantly, an engineering base also provided a lot of flexibility in the real world, Heller adds. “It prepares you to be able to work hard and solve problems.”

Heller says that his engineering education at Duke prepared him for the job in several ways. “My education gave me confidence and problem-solving skills, if they (office personnel) ask me to do something I know how to do it without having to ask questions,” he said.

Besides helping to consolidate phone bills, creating spreadsheets, and doing other office necessities, Heller spends time driving out to various properties and doing what the real estate business calls “mystery shopping.” Mystery shopping involves going out to a property and essentially pretending to be interested in it for the purpose of gathering information for market analysis.

Heller says that his summer employment has been a great real world experience but hasn’t changed his study plan much. “I’m more inclined to continue studying sciences.”

As for Heller’s career or future plans? Heller says, “I have no idea yet. I’m thinking maybe grad school.”

Perhaps that will remain a mystery as well, at least for now.

Lightning’s Mirror Image, Only Much Bigger

admin — Mon, 24 Aug 2009 10:40:14 -0400

DURHAM, N.C. -- With a very lucky shot, Duke University scientists have captured a one-second image and the electrical fingerprint of a huge jolt of lightning that flowed 40 miles upward from the top of an offshore tropical storm.

These rarely seen, highly charged meteorological events are known as gigantic jets, and they flash up to the lower levels of space, or ionosphere. While they do not occur every time there is lightning, they are substantially larger than their downward striking cousins.

Watch video

Images of gigantic jets have only been recorded on five occasions since 2001. The Duke team caught a one-second view and magnetic field measurements that are now giving scientists a much clearer understanding of these rare events.

The gigantic jet was recorded during Tropical Storm Cristobal, which skirted the North Carolina coast in July 2008. The camera that caught it was near Duke University in Durham, more than 150 miles inland.

“Despite poor viewing conditions as a result of a full moon and a hazy atmosphere, we were able to clearly capture the gigantic jet,” said study leader Steven Cummer, Jeffrey N. Vinik associate professor of electrical and computer engineering. Cummer’s report appeared in the journal Nature Geoscience.

“Our measurements show that gigantic jets are capable of transferring a substantial electrical charge to the lower ionosphere,” Cummer said. “They are essentially upward lightning from thunderclouds that deliver charge just like conventional cloud-to-ground lightning. What struck us was the size of this event.”

It appears from the Duke measurements that the amount of electricity discharged by conventional lightning and gigantic jets is comparable, Cummer said.

But the gigantic jets travel farther and faster than conventional lightning because thinner air between the clouds and ionosphere provides less resistance. Whereas a conventional lightning bolt follows a six-inch channel and travels about 4.5 miles down to earth, the gigantic jet recorded by the Duke team contained multiple channels and traveled about 40 miles upward.

“Given that reservoirs of electric charge in thunderstorms are the sources for both lightning and gigantic jets, and that both events involve contact between these reservoirs and a very large conducting surface, it is not surprising that their charge transfers are comparable,” he said.

Scientists do not know what conditions or what types of storms are conducive to gigantic jet formation.

It has been difficult in the past to obtain images of gigantic jets because they occur so quickly that cameras have to be trained on them at the precise moment they occur.

Cummer caught the gigantic jet almost by accident. The equipment had been set to capture another phenomenon known as sprites, which were first photographed in 1989. They are electrical discharges that occur above storm clouds and are colored red or blue, with jellyfish-like tendrils hanging down.

He maintains a low-light video camera trained to the sky and programmed to start recording when specific meteorological conditions occur. At the same time, other equipment constantly measures radio emissions in the same sector to capture electrical events. A special GPS system ensures that the readings from all the equipment are synchronized.

Cummer is planning to install a low-light, high-speed camera to capture gigantic jet images in color, which could provide additional information about chemical processes and temperatures inside the phenomenon.

The research was supported by the National Science Foundation. Other Duke team members were Jingbo Li, Feng Han, Gaopeng Lu and Nicolas Jaugey. Walter Lyons and Thomas Nelson from FMA Research, Fort Collins, Colo., also participated.

Novel Approach Could Improve Protein-Based Drugs

admin — Thu, 20 Aug 2009 10:43:23 -0400

DURHAM, N.C. – A new method for attaching a large protective polymer molecule to a protein appears to improve protein drugs significantly.

Bioengineers at Duke University developed the new approach and demonstrated in an animal model that the newly created protein-polymer combinations, known as conjugates, remained in circulation significantly longer than an unprotected protein.

The scientists say they are encouraged that their findings represent a new strategy to improve the efficacy of protein drugs.

Protein-based drugs are an increasingly important new class of drugs, said Ashutosh Chilkoti, Theo Pilkington Professor of Biomedical Engineering at Duke’s Pratt School of Engineering. He cited such examples as insulin for the treatment of diabetes and more exotic “magic bullet” antibodies like herceptin that are used to treat certain cancers.

Unmodified proteins that are injected into the blood are quickly recognized by the body and broken down or cleared by the body’s defense system, which limits their effectiveness as drugs. To get around this problem, drug makers have been attaching another molecule, a polymer known as polyethyleneglycol (PEG), to the protein in order to protect it. But this approach has its own drawbacks.

“The current method of combining the two molecules often only works with 10 to 20 percent efficiency, so that a lot of the very expensive starting materials are wasted,” said Chilkoti, who had the results of his team’s experiments published the Proceedings of the National Academy of Sciences. “Additionally, the two large molecules are attached by a small chemical link and often these linkages can occur at many different sites on the protein, so the final product is poorly defined.”

Chilkoti took a different approach. Instead of combining two large molecules, he grew the polymer out from the protein itself, increasing the efficiency of the protein by more than 70 percent and greatly extending the amount of time it remained active in a living model.

“We also addressed the problem of getting a pure and well-defined product by growing the polymer from a single, unique site on the protein,” he said. “Another twist to our work is that instead of using PEG, we used a somewhat different polymer that turns out to be as good and perhaps even better than PEG in extending circulation of the protein in the body.”

There are many protein-polymer based medications in use today, such as human growth hormones, drugs to stimulate blood cell formation in cancer patients and anti-viral agents. Chilkoti will be reviewing existing protein-polymer drugs to determine if the new technique can improve their effectiveness.

In their experiments, the researchers used myoglobin, a protein responsible for creating the red pigments that give meat its color. Instead of creating a chemical bond between myoglobin and the polymer, the Duke researchers chose a specific spot on the protein, known as the N-terminus, and then grew the polymer from that specific location. Every protein has an N-terminus, so this method should be broadly useful, Chilkoti said.

After demonstrating they could create a stable compound using the new method, the researchers tested how well it worked by comparing its actions to the conventional compound in mice.

“The conventional compound – myoglobin – had a half-life of three minutes and was totally eliminated by two hours,” Chilkoti explained. “By contrast, the new compound had a half-life 40 times greater and remained in circulation for 18 hours. The longer a protein remains in the system and is active, the more it helps the patient.”

“The dramatic improvement in how the new compound acted encourages us that this new approach will have broad applications in improving the efficacy of many protein drugs,” Chilkoti said.

Another benefit of this approach, according to Chilkoti, is that the polymer should naturally degrade in the body over time and be easily excreted. “Because the compound is biodegradable, we should in principle be able to make even larger protein-polymer combinations with potentially even better pharmacologic properties,” he said.

The researchers plan to apply their invention to other protein-based therapies, such as for cancer and diabetes, to determine if they can improve effectiveness of the protein drug while reducing its undesirable toxic effects.

Other Duke team members were Weiping Gao, Wenge Liu, J. Andrew Mackay, Michael Zalutsky and Eric Toone.