Spotlight on 2009 CAREER award recipients
The National Science Foundation is supporting early-career engineering research in such areas as cell fusion, data processing in digital communication, and breast cancer screening and diagnosis methods. Earning prestigious CAREER awards in 2009 are Industrial and Systems Engineering Professor Oguzhan Alagoz, Electrical and Computer Engineering Assistant Professor Stark Draper, Biomedical Engineering Assistant Professor Brenda Ogle, and Mechanical Engineering Assistant Professors Dan Negrut and Kevin Turner.
Oguzhan Alagoz: Breast cancer screening models
Tailoring clothing to fit a woman is a straightforward process: take measurements and alter accordingly. Similarly, tailoring breast cancer screening to fit a woman involves taking into account individual risk factors, like age and family history, and altering a mammogram schedule accordingly.
Alagoz is working to optimize breast cancer screening policies for various populations of women and optimize follow-up decisions, such as recommendations for biopsies or additional mammograms. He will explore whether a dynamic screening interval, such as testing younger women every six months (since breast cancer is more aggressive in younger women) and testing older women every two years, is a better strategy than the current static strategy that tests every woman every year after age 40. Alagoz will also examine the effects of using sensitive but expensive technologies like MRI.
In addressing these issues, Alagoz may answer complex questions about why certain demographics of women suffer from higher breast cancer mortality rates.
Alagoz’s work is the first study to use stochastic optimization techniques and clinical data to find cost-effective strategies for personalized breast cancer screening, which could reduce the number of unnecessary biopsies and short-term follow-up mammograms conducted in the United States each year. His models could also provide a framework to develop appropriate screening schedules for other cancers and diseases, such as prostate and colorectal cancers.
The larger objective of Alagoz’s work is to introduce medical researchers to engineering tools and techniques, and he frequently collaborates with medical researchers to explain his models and show them how engineering can tackle health-related problems.
An example is Alagoz’s work with Radiology Associate Professor Elizabeth Burnside to develop a breast cancer prediction model. The model relies on sequential decision techniques, which account for decisions that are made multiple times and have a cascading effect, such as an abnormal mammogram prompting a woman to have another mammogram in six months. Using this model, a radiologist could tell a woman that a mammogram abnormality has, for example, a 10 percent chance of being cancerous, so if the woman is advised to undergo a biopsy, she will understand the realistic likelihood of cancer.
The National Institutes of Health originally funded the model, and Alagoz will now expand it as part of his CAREER award.
The work has been a success, Alagoz says, because he collaborated closely with Burnside. “You must involve healthcare professionals in research like this because the math won’t work without their help, and you must use real data when it comes to health-related issues,” says Alagoz.
He is also working to bring more engineers into healthcare by training PhD students and involving undergraduate students in his research.
“We have to remove inefficiencies from the healthcare system, and I think industrial engineering can play a big role in that,” he says. “We can truly make a difference.”
Stark Draper: Accelerating digital communications
Electrical and Computer Engineering Assistant Professor Stark Draper is a computer philosopher of sorts, as evidenced by some of the questions he poses to his students: What kind of digital communication technologies are possible and what are not? What are the implications from the way we conceive and design real-world systems? Draper sees possibilities in new architectural models for digital communications, and his work has earned him a CAREER award.
His research suggests a re-thinking of important classes of digital communication systems. Traditionally, communication systems are designed to handle data as large, discrete and unrelated units of information. However, in many modern applications — including high-quality video conferencing, wireless media streaming and wireless factory automation — data unfurls in a stream. To be useful for real-time decision-making, streaming data needs to be conveyed in a continuous and time-sensitive fashion.
“When the current architecture was originally developed, it didn’t matter if an email arrived immediately or ten minutes after it was sent,” explains Draper. “The underlying assumption of the model was that if you needed instant communication, you picked up the phone.”
Draper will redefine assumptions and design models to meet user demands for networks to handle streaming data more efficiently and reliably. In current models, when a computer sends a data packet to another computer, the latter either confirms that the packet has arrived or asks for it to be resent, and the turnaround time can be lengthy. A more efficient “conversation” between computers could increase the speed of data transfer.
He has already developed tools to improve this conversation and now is studying how to integrate them into both larger-scale and wireless networks. He is also working with industrial collaborators to develop an application that will test the ideas and algorithms he developed. The applications for the algorithms could be far-reaching and benefit a variety of industries that rely on sensing, communication and control. “I’ve been fortunate to find such talented and energetic collaborators across the campus,” Draper says. “My research has been strengthened and broadened here at UW-Madison.”
Enabling cheaper, faster and more reliable digital communication is also important for a global society that is increasingly reliant on massive exchanges of information, says Draper, whose interests have led him to join the team of UW-Madison faculty members who teach InterEngineering 102: Introduction to Society's Engineering Grand Challenges. Based on challenges outlined by the National Academy of Engineering, the class aims to aims to demonstrate to students how engineers are crucial to improving the quality of life around the world. Draper will begin co-teaching the course in 2010.
At the graduate level, Draper teaches courses on information theory, error-correction coding, and statistical signal processing, and he is developing a course on large-scale statistical inference with applications in machine learning, signal processing, and communications. Draper is also working to pique the interest of pre-collegiate students: He was a guest speaker at the 2009 UW-Madison Engineering Summer Program, which encourages underrepresented high school students to pursue engineering and science.
Brenda Ogle: Contributions to stem cell analysis
While a benefit of stem cells lies in their potential to develop into many cell types, that tendency to differentiate also frustrates researchers trying to study stem cells without disturbing them. “Many stimuli — whether it be mechanical, electrical, chemical — can induce this differentiation,” says Biomedical Engineering Assistant Professor Brenda Ogle. “Often we don’t realize we’re inducing these changes, and so the cells have to be constantly monitored. The large numbers of cells to be analyzed, and the sensitivity of stem cells to external stimuli, makes this a difficult task. ”
As part of her CAREER award, Ogle is developing stem cell analysis tools that offer researchers the flexibility to study not only individual cells, but also multicellular entities and small tissue-engineered constructs. One technology builds on a flow cytometer, an analysis tool in which large volumes of individual cells flow quickly through a chamber. There, a laser hits the cells and reflects light that provides researchers information about physical and chemical characteristics of a cell.
Called multi-photon flow cytometry, Ogle’s technology incorporates fluidics that can handle not only single cells and larger, multicellular aggregates or tissue-engineered constructs. In addition, it employs multiphoton optics that enable researchers to move beyond surface analysis and probe deep within the larger cellular structures.
To develop their technology, Ogle and her students drew on UW-Madison experts in optics (Biomedical Engineering and Molecular Biology Assistant Scientist Kevin Eliceiri) and microfluidics (Biomedical Engineering Professor David Beebe and Assistant Professor Justin Williams).
The team has filed a patent application for the technology — an add-on to the current cytometer — through the Wisconsin Alumni Research Foundation. With the CAREER funding, Ogle and her students plan not only to improve their proof-of-concept prototype and share it with other stem cell researchers, but also use it to study stem cell fusion processes.
Ogle and others are exploring the therapeutic benefits of fusing stem cells with mature cells, such as cardiomyocytes, or heart muscle cells. While researchers have demonstrated cell fusion in vivo and in vitro, only recently have they begun to study how this fusion occurs. “We want to know what happens to cells that undergo fusion over time, and so a nice way to analyze them in a high-throughput way is with this multi-photon flow cytometer,” says Ogle.
She and her students also hope to develop sorting capabilities for the technology, so that if they or other researchers identify cells that exhibit certain properties, they can isolate, culture and study those cells separately.
Currently, the multi-photon flow cytometer resides in the campus Laboratory for Optical and Computational Instrumentation, and she aims to make it available to a broader range of researchers both on and off campus. Her efforts may lead to a consortium that enables member companies to collaboratively generate new technologies that advance stem cell biology and help translate stem cell research into commercial products.
Dan Negrut: Granular flow simulations
In summer 2008, 12 African American high school students from Madison, Milwaukee and Chicago spent a week on campus with Mechanical Engineering Assistant Professor Dan Negrut. The students participated in a pilot program designed by Negrut to promote computational science, engineering and college in general.
In addition to being a fun experience for the students, the program, dubbed Promoting the Computational Science Initiative, or ProCSI, attracted the attention of the National Science Foundation, which awarded Negrut a CAREER award. Negrut’s high school program exposes students to the work of his team at the UW-Madison Simulation-Based Engineering Laboratory. The lab focuses on using computer modeling and simulations to understand the dynamics, or motion, of complex mechanical systems. One of the group’s projects is to calculate granular flow dynamics with high-performance parallel computational hardware.
Negrut and his students have developed simulations that can calculate all the collisions between 10 million bodies, such as grains of sand, in as little as four seconds. To do this, the team uses parallel processing units that execute commands simultaneously, rather than sequentially as in regular computer processors. The parallel solution developed by Negrut can perform a multi-million body collision detection task about 40 times faster than can a regular computer. (View simulations at sbel.wisc.edu/Animations/index.htm.)
The next step for Negrut’s research is to compute the friction and contact forces between grains by solving differential equations that explain exactly how each grain moves and interacts with other grains. Solving dynamics equations with parallel computers has applications far beyond granular material, as differential equations are used in a broad range of engineering problems. For example, Negrut’s research could eventually be used to look at the movement of atoms. For now, his work has applications in construction vehicle and military vehicle design, and he has ongoing projects with P&H Mining of Milwaukee and the U.S. Army. Negrut is also collaborating with Professor Alessandro Tasora from the University of Parma, Italy, and Mihai Anitescu, a computational mathematician from Argonne National Laboratory.
How does Negrut make his research accessible to high school students? He explains problem-solving as a step-by-step process where each component builds on itself. The first day of ProCSI, the students learn about mechanical engineering problems. The next day they learn how math is used to solve engineering problems. Then they learn how computers can be used to solve the math that solves the engineering problem. On the final day, the students learn how to put all of the problem-solving components together and actually run simulations themselves.
Kevin Turner: Research on micro-devices
Imagine reading this article on an electronic screen that could be rolled up and put into a pocket. Someday, the electronics to power this kind of screen may be produced by a process that relies on a very simple tool: a stamp.
Reliable flexible displays are only one of a variety of new microelectronic and micromechanical devices that may become possible thanks to fundamental research by Mechanical Engineering Assistant Professor Kevin Turner. Turner is studying the underlying physics and mechanics of adhesion during a process called microtransfer printing. He will use his research to improve microtransfer printing manufacturing processes, which eventually could be used to produce a host of innovative technologies, such as advanced optoelectronic devices, high efficiency solar cells, and new types of microelectromechanical systems. His work has garnered a CAREER award.
Microtransfer printing is essentially a process that “prints” with solid materials rather than ink. A silicone stamp is designed with a smooth side that is used to pick up micro- or nanostructures from the substrate on which they are originally fabricated. The stamp is used to transfer these structures — which may be fully processed integrated circuits or building blocks for more complex devices — and places them down on another substrate or functional device.
Traditional silicon-based microelectronic devices are constructed on thick wafers, which produce rigid devices. To create a flexible device, such as a flexible display or processor, very thin layers of single crystal silicon can be peeled from a thick substrate and placed onto a compliant substrate. Even though silicon is a stiff, brittle material, it can be made extremely flexible by making it less than 1-micron thick. However, a key challenge is that there are few techniques available to move large-area thin layers, which are floppy and fragile. Microtransfer printing has emerged as a potential option for thin layer transfer since it can be done quickly and used to create a large number of devices.
Microtransfer printing relies on surface adhesion that occurs thanks to a force known as the van der Waals force. At room temperature, the smooth surface of the silicone stamp bonds directly to micro- or nanostructures via these forces, allowing the structures to be picked up. Turner will use a combination of modeling and experiments to investigate the fundamental behavior of van der Waals-based adhesion in microtransfer printing processes. Based on this fundamental study, he will explore using surface texture and geometric structures on the surfaces of the silicone stamps to control adhesion. He also will identify optimal stamp designs for the pick up and release of micro- and nanostructures, will research new types of composite stamps based on materials other than silicone, and will examine how different loading techniques can be used to further control adhesion.
“If we measure the forces that govern microtransfer processes and develop computational models that capture the fundamental interfacial behavior, then we can examine higher-level manufacturing questions, ” Turner says. “We then can use that knowledge to design more effective manufacturing processes and techniques.”
He plans to develop advanced graduate courses in adhesion and contact mechanics, as well as an undergraduate elective in the design and manufacturing of nano- and microsystems. He also will host local K-12 teachers in his lab during the summer and will work with the teachers to develop lesson plans about nanotechnology for elementary and high school students.