Duke has made a name for itself in groundbreaking scientific research earning a Nobel prize, numerous grants and countless headlines. Through the practical application of technologies, researchers have been able to solve diverse sets of problems. In the past year, Duke researchers have made major headway on an HIV vaccine, created a working “invisibility cloak” and used lasers to analyze ancient art.
Mischief Managed: Real world invisibility cloaking
The David R. Smith Research group— also known as the Meta Group—is incorporating meta-materials in a wide range of applications, including cloaking objects from detectors and recreating 3D images.
Meta-materials are synthesized molecules that have electromagnetic properties that exceed those of regular chemically engineered ones. One such property is to accurately alter the electromagnetic field of waves, allowing light waves to be bent.
The group—funded primarily by the Department of Homeland Security, the Air Force Office of Scientific Research and the Department of Defense’s Multidisciplinary University Research Initiative program—focuses primarily in three research areas: electromagnetic meta-materials, transformation optics and plasmonics.
“We have a lab space set up for microwave meta-material measurements,” said Jack Mock, a research associate and technician for the group. “Right now they’re trying to accomplish compressive imaging using meta-materials.”
By using electromagnetic waves from a meta-material source, John Hunt, a graduate student in electrical and computer engineering working on compressive imaging, explained that compressive imaging is able to create images with just one sensor, and without the lenses and mirrors required by normal cameras. In addition, compressive imaging technology is much more cost-effective.
“If you could make a new type of lens that focuses different points in a scene onto the same detector for each different frequency, you could make a fast, cheap, monochrome microwave imaging system—with no moving parts,” Hunt wrote in an email June 24. “Our group has recently demonstrated a way to use meta-materials to build a lens that does exactly this—we steer light to make things visible!”
Hunt hopes to improve this technology to create more complicated image replications, applications could potentially lead to systems that help prevent automobile collisions and more efficient, line-free airport security.
This process is the opposite of another application made possible through the use of meta-materials—electromagnetic cloaking. Instead of having electromagnetic waves collect at a source, researchers have been working on perfecting cloaking technologies which instead bend waves away from a single point in order to make an object effectively undetectable.
Yaroslav Urzhumov, a research faculty member in the department of electrical and computer engineering, recently created a 3D-printed cloaking device that could hide virtually any object from microwave detectors in a single plane. Nathan Landy, a graduate student in electrical and computer engineering, earlier created an advanced cloaking device using meta-materials making objects undetectable at higher frequencies.
The lab hopes to continue their research into devices with further cloaking abilities, Urzhumov said in an earlier interview with The Chronicle.
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Although transformation optics, the field that deals with bending light fields with metamaterials, have come a long way, it becomes difficult to construct devices that can cloak objects from very high wave frequencies, Mock explained. Thus, researchers have turned to plasmonics, which are bound by normal elemental properties unlike metamaterials, and have nanotechnological applications..
Plasmonic nanostructure technology has now become the avenue for scientists to attempt to develop cloaking devices at visible wavelengths which metamaterials have not been able to do, Mock said.
“The elements we usually make meta-material objects from are resonant, meaning that they’re like little antennas that have a very strong resonant frequency at a microwave-frequency which then strongly affect an electromagnetic wave,” Mock said. “It turns out that plasmonics is the obvious way to create a resonant element in visible wavelength.”
The applications that arise from the study of plasmonics include new DNA markers and nano-sensing technologies, Mock said.
Although the David R. Smith group still has a ways to go before coming out with a Harry Potter cloaking device, researchers are optimistic about continued interest by the government in their cloaking and meta-material research.
Searching for the HIV solution
The Center for HIV-AIDS Vaccine Immunology at Duke is edging closer to overcoming one of the most challenging scientific endeavors of the modern era—to find a preventative cure for HIV.
CHAVI director Barton Haynes, who has been working on finding a vaccine for the HIV infection for the past 25 years, has helped lead one of the most comprehensive national efforts on the topic, funded by the National Institutes of Health.
Using samples found from individuals who produce broad-neutralizing antibodies, Haynes, in collaboration with scientists from all over the world, has traced and identified important trends in the virus and the mechanisms which are most vulnerable.
“The HIV virus is a very formidable foe, and changes its outer coat all the time and keeps the immune system confused,” Haynes said. “We know what we need to do, now we need to take that information and develop a practical vaccine.”
CHAVI, one of 16 centers funded initially by a $350 million grant from the National Institute of Allergy and Infectious Diseases in 2005, received continued funding in June 2012 to further its efforts in finding a vaccine. Other universities involved in the research at CHAVI include Harvard University, the University of Alabama-Birmingham, Oxford University in England, University of North Carolina at Chapel Hill and several universities across Africa.
“We are being asked to do something that no vaccine is being asked to do, and that is to totally prevent infections,” Haynes said.
Unlike measles or mumps which, due to vaccines, remain in the human genome without the occurrence of disease, the eradication of AIDS rests upon preventing completely the implanting of HIV to the genome.
Haynes and his research collaborators have found nearly 20 individuals who produce the “right kind of broad-neutralizing antibodies” that can prevent AIDS implantation and are beginning to create clinical trial vaccines using these individuals’ genetic codes.
“We have some fabulous people working with us, and we have some collaborative teams working in England and the United states,” Haynes said. “We need to hit the virus in four or five different places so that it can’t mutate.”
Cracking the next Da Vinci code
Researchers at the Warren Group are using advanced laser techniques to uncover hidden truths in ancient art.
“In general, what we do that’s different than everyone else is advanced laser technology applied in very unique ways,” said Warren Warren, James B. Duke professor of chemistry.
The group developed a laser system based on pump-probe spectrometry, explained Warren. The technique aims two laser pulses through a series of lenses and finally to a custom-built microscope. The pulses excite the molecules at the focal point of the microscope’s lens and, after a billionth of a millisecond delay, a second pulse goes to the same spot, yielding different properties. This process therefore leaves a unique signature on each spot, and properties about the material are gathered based on the signature.
This laser fixture has been used already in different pottery samples, a variety of ancient artifacts and Puccio Capanna’s painting “Crucifixion,” lent to the lab from the North Carolina Museum of Art. Projects concerning art analysis for conservationist scientist are being carried out in the lab by Tana Villafaña, a graduate student in chemistry.
The group mainly focuses on providing biomedical researchers with tools to more easily identify problems through laser and MRI technologies, explained Warren. The lab has also developed techniques to analyze moles and see whether or not they may lead to melanoma, a dangerous skin cancer.
“We do optical imaging, we’ve developed technologies that nobody else has,” Warren said. “In medical research, we know what this technology is good for—things like finding a way to improve the way to increase doctors’ ability to diagnose melanoma are important.”
Analyzing ancient art is still on the agenda in the future. Having recently received a large National Science Foundation grant to develop a portable version of the laser-pulse technology found at Duke, the Warren group hopes to analyze many more pieces, including the mysterious Terracotta Warriors found in Shaanxi Province, China.
“We’ve been doing a lot of work on pottery, and a variety of work on ancient artifacts,” Warren said. “We can learn a lot of important things, like stopping photodegradation.”
Creating robots and predicting protein mutations
From creating the world’s smallest untethered controllable microrobots to predicting drug resistance, the Donald Lab uses advanced technologies to solve a myriad of biomedical problems.
“We extended the boundaries of what is possible with provable algorithms,” explained Bruce Donald, James B. Duke professor of computer science and biochemistry, in an email June 19.
A few years ago, when the lab was working with industrial robots, students decided to program one of them to cut an ice-cream cake for the lab’s namesake professor Bruce Donald’s birthday, with only minor complications.
The lab has conducted successful research on reprogramming an antibiotic-producing enzyme, predicting MRSA resistance mutations using “Open Source Protein Design For You” software developed by the lab and designing molecular probes to selectively pull down broadly neutralizing antibodies against HIV-1, Donald said. The software has also helped design protein to peptide interactions to elucidate underlying structures in cystic fibrosis.
“Drug resistance resulting from mutations to the target is an unfortunately common phenomenon that limits the lifetime of many of the most successful drugs,” Donald, James B. Duke professor of computer science and biochemistry, said. “OSPREY’s prospective predictions will enable the possibility to overcome drug resistance early in the iterative drug discovery process.”
The lab also uses microelectronic systems for biomedical purposes, including the creation of the first untethered controllable microrobots, massively-parallel distributed micromanipulation and microassembly and nanotechnological approaches to neuroscience, Donald said.
The lab hopes that through collaborative effort with other Duke scientists, they will be able to continue their work in biomedical studies.
“We’re interested in developing drug-like proteins, peptides, and other molecules that could help with bacterial infections, fungal infections, cystic fibrosis and HIV, and we have collaborations to do that,” Donald said.