UNO Magazine: Walk This Way

The following story appeared in the most recent issue of the UNO Magazine, which highlighted how professors are serious about play, studying how it aids learning and development, using it to teach math or to aid recovery from a stroke, or just to have fun. Read the magazine online as a Flipbook or download a PDF.

Nate Hunt can’t help himself. He finds that whenever he spots a fox squirrel on the move he must stop, watch and wonder.

“I tend to nerd out and stare,” the UNO biomechanics assistant professor says.

Hunt finds himself thinking about the interaction between their cognitive and movement control capabilities. He studies the way their bodies are built — the interaction between their neural control and morphology. He postulates how those capabilities interact to allow the fox squirrel to move as it does.

Basically, he marvels at how the fox squirrel glides through complex, three-dimensional canopies – his word for trees – with such proficiency. His attention then turns to what humans can learn from fox squirrels to improve the way they get about and, most important, get about without falling.

Hunt’s investigation of how the fox squirrel’s leaps, lunges and safe landings translate to better human mobility is one example of why UNO’s biomechanics faculty attract national attention and earn widespread funding support, says Nick Stergiou, founding biomechanics department chair. “We have some very smart people working here.”

“Here” is the recently expanded Biomechanics Research Building, which anchors the southeast corner of UNO’s main campus. Inside, 13 faculty members, along with staff, postdoctoral, graduate and undergraduate students, conduct their research, which often includes animals. Some of those animals – including Hunt’s cockroaches (the other focus of his work) are kept at the research building; others are kept elsewhere or studied in their natural environment.

“Studying animal behavior, we can massively improve the way humans would engage their environment,” Stergiou says. “Animals, many times, are way better than we are.”

Pigs

When Alexey Kamenskiy went looking to create an animal model to better understand how human tissues interact with surgical devices, he chose pigs.

“The best animal for cardiovascular research is probably a pig, says Kamenskiy, who joined the biomechanics department earlier this year. A pig’s cardiovascular system, he explains, is similar to that of humans. Pigs respond similarly to surgical treatments. Their vessel size is compatible with most of the devices used in surgery with humans.

He dispels some common misperceptions people have of pigs, saying they’re smart and clean. “They’re fun to work with,” Kamenskiy says.

Nebraska is a good place for large-animal research, he says, pointing out that the pig population in Nebraska (3 million) exceeds its number of humans (1.92 million).

Kamenskiy studied human tissues while earning his doctoral degree in engineering mechanics at UNL. That led to him creating a computational model to understand how these tissues interact with surgical devices. Next came creating an animal model to test the peripheral stents he is working to perfect.

Mice, a standard suggestion for a research subject, aren’t an option, he says, because their blood vessels are too small. His research animals are kept at nearby UNMC.

Kamenskiy’s work began with a five-year grant from the National Institutes of Health to determine which commercially made surgical devices resulted in the best patient outcomes. “The outcome is there are some a little better, some are worse,” he says. “Bottom line is, none of them are good.”

His current task — funded through an additional five-year grant – is to develop a device to encourage better flow through blood vessels. The typical approach through surgery is a bypass graft around the blockage. A stent is placed inside the blood vessel, pushing plaque to the side. Blood then can flow through the wound.

Such interventions don’t work well in leg injuries, though, and one-third to one-half of patients have recurring symptoms that require further intervention. The stent sometimes breaks or rubs on the vessel in a way that causes the vessel to try to repair itself. Sometimes, the vessel is compromised.

Along the way, Kamenskiy says, his study of human tissues provided insight into how vessels are affected when a person smokes or has diabetes.

Another research focus is how to buy time for those who suffer tears in a major artery or a severe chest injury to get medical care. Kamenskiy and UNMC vascular surgeon Jason MacTaggart are developing a device to be inserted through the injured person’s groin, with multiple balloons connected by a shunt that can isolate the wound but allow blood to continue to flow to vital organs.

The goal is to train non-clinicians, for use in such places as battlefields, to insert the device. “What’s the best animal to use for training? Pigs.”

The Fox Says …

Hunt’s research subject of choice is the fox squirrel because of the strong muscles on its hind legs and large, sharp claws.

“These things allow them to do huge leaping jumps, land, and maintain attachment,” Hunt says.

In order to use those capabilities, he says, the fox squirrel must have neural capabilities to allow it to learn and make decisions affecting its movement control.

His next preference is the cockroach. His intrigue stems from how the insect – colloquially known as the water bug – can travel along canopies (in this case, his word for bushes) at such a fast clip. The American cockroach is potentially the fastest animal on earth relative to its body size, able to take 45 steps in one second.

His experiments focus on how American cockroaches run across branches with different diameters and slopes. He’s especially interested in how they change their locomotor patterns as they move across these branches.

Hunt, who earned his doctorate at the University of California Berkeley, typically has a colony of 100 to 200 cockroaches in his lab ready to run. He entices fox squirrels to participate in his outdoor experiments with peanuts. He films them with drones at high speed as they maneuver through his obstacle courses, then breaks down their movements and responses for closer study.

Experiments using animals are monitored through the Institutional Animal Care and Use Committee – a joint UNO-UNMC committee, Stergiou says.

Hunt says he has two current lines of research – the first involves animals indirectly and the second directly:

• Balance in adults, especially what causes people to slip. So he causes people to slip then studies their reaction. “There are good and bad responses.” How animals move and stabilize themselves can provide direction.

• Movement along terrain. This is where studying fox squirrels and American cockroaches apply. Squirrels make long leaps relative to their body size. What happens when their leap is not accurate? “Do you try to stick the landing or rather grab on with legs or arms and try to recover? Do you try to reduce the consequences of the coming fall? Put your arms down and brace for impact?” Responses must occur in milliseconds to be effective. Research suggests that our neural responses are plastic, meaning they can change.

Hunt’s research on how animals move through their terrains extends beyond humans and into robotics. “We want robots to navigate the kinds of environments we do,” he says.

Only better. Truth be told, Hunt says, humans aren’t the best subject. “In terms of high performance and to be mobile in a variety of terrains, I would not consider humans to be the model organism for these endeavors.” Thus for Hunt, fox squirrels and American cockroaches.

More recently, Hunt finds himself intrigued with dragonflies and the way they can change directions on a dime. He’s yet to determine how the dragonfly might be part of a future study. “Dragonflies often are compared to jet fighter planes. That interests me. And the fact they can mate on the fly. Humans can’t do anything near that.”

Growing By Leaps and Bounds

Nate Hunt’s cockroaches have room to roam in UNO’s recently expanded Biomechanics Research Building.

Not that they have free rein in the building. But Hunt, assistant professor of biomechanics, wants to see how humans can improve their mobility by studying the way cockroaches move about.

Space in the recently expanded 53,000-square-foot research building already is in demand, says Nikolaos Stergiou, director of biomechanics at UNO. The 30,000-square-foot addition, dedicated in October, already is full of activity, he says.

Credit the additional space for giving Stergiou and his colleagues some wiggle room. The added space translates to eight additional research labs, a data processing center, and workspace for the 13 faculty members, 35 undergraduate students, and 25 graduate students.

And people are noticing their handiwork. Four biotechnology companies wish to locate in the Biomechanics Research Building. “They want to work side-by-side with our people, shouldering in research greatness,” Stergiou says.

And they are intrigued by what’s inside the Biomechanics Research Building. Stergiou described some highlights, which all are geared toward the study of the mechanical laws relating to the movement or structure of living organisms:

• A second virtual reality laboratory. This one comes with a treadmill that has 6 degrees of freedom of movement. “Not only up and down, but sideways as well. Just imagine something like that.”
• A machine shop large enough for people to drive their vehicles inside. Not to have their oil changed, Stergiou says, but to have sensors installed that will assist scientists to study how we drive when we get older.” Scientists can, for example, track acceleration time for older motorists and the types of abrupt reactions they make while driving, Stergiou says, which will determine who should drive and who shouldn’t.
• An underwater treadmill that allows scientists to test the effects of gravity at different levels other than the earth’s 9.8g. Scientists can study, for example, how buoyancy and subsequently decreased gravity could help rehabilitate injuries by determining how much weight the joint can bear.

Finally, the research building has a laboratory that houses Jorge Zuniga’s 3-D printing capabilities, which the associate professor uses to build prostheses for children with congenital deformities. He’s studying how congenital deformities create an imbalance in a person’s brain. “But what if I give you this prosthesis? Does this affect again the way the brain works?” The laboratory also houses a 3-D printer that, instead of plastic, creates in metal.

Stergiou says he wants Nebraskans to know that the Biomechanics Dept. is paying its own way through private donors and research funding. The department recently received a National Institutes of Health $10.3 million grant – the largest in university history – which allows the department to establish three new research cores: the Movement Analysis Core, the Nonlinear Analysis Core, and the Machining and Prototyping Core.

In 2013, the biomechanics building housed Stergiou’s research group. Six years later, the Biomechanics Research Building houses a department (biomechanics), a center (for Research in Human Movement Variability), and a division (for biomechanics and research development).

Stergiou says the department isn’t finished growing — a theme he repeated at the building addition’s dedication.

“If anyone thinks we are finished, I beg to differ.”