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biomechanics

From Juggling to Biomechanics

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For any aspiring juggler, the path to greatness requires mastering the dreaded “five-club backcross.” It’s a move that begins by juggling five clubs in front of your body and transitions to doing the same thing behind your back! Dr. Noah Cowan has nailed it once, and vows to do it again one day.

But this NIH-funded neuroscientist and bioengineer, who directs the Locomotion in Mechanical and Biological Systems (LIMBS) Laboratory at Johns Hopkins University’s Whiting School of Engineering in Baltimore, doesn’t have much time to practice his juggling these days. Instead, he is focusing on ways to use virtual juggling, such as the ball-and-paddle system shown in the video above, to explore the biomechanics of motion. His ultimate goal?  To apply what he’s learned to advance the fields of robotics, prosthetics development, and physical therapy.


Watching Cancer Cells Play Ball

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Credit: Ning Wang, University of Illinois at Urbana-Champaign

As tumor cells divide and grow, they push, pull, and squeeze one another. While scientists have suspected those mechanical stresses may play important roles in cancer, it’s been tough to figure out how. That’s in large part because there hadn’t been a good way to measure those forces within a tissue. Now, there is.

As described in Nature Communications, an NIH-funded research team has developed a technique for measuring those subtle mechanical forces in cancer and also during development [1]. Their ingenious approach is called the elastic round microgel (ERMG) method. It relies on round elastic microspheres—similar to miniature basketballs, only filled with fluorescent nanoparticles in place of air. In the time-lapse video above, you see growing and dividing melanoma cancer cells as they squeeze and spin one of those cell-sized “balls” over the course of 24 hours.


Robotic Exoskeleton Could Be Right Step Forward for Kids with Cerebral Palsy

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More than 17 million people around the world are living with cerebral palsy, a movement disorder that occurs when motor areas of a child’s brain do not develop correctly or are damaged early in life. Many of those affected were born extremely prematurely and suffered brain hemorrhages shortly after birth. One of the condition’s most common symptoms is crouch gait, which is an excessive bending of the knees that can make it difficult or even impossible to walk. Now, a new robotic device developed by an NIH research team has the potential to help kids with cerebral palsy walk better.

What’s really cool about the robotic brace, or exoskeleton, which you see demonstrated above, is that it’s equipped with computerized sensors and motors that can detect exactly where a child is in the walking cycle—delivering bursts of support to the knees at just the right time. In fact, in a small study of seven young people with crouch gait, the device enabled six to stand and walk taller in their very first practice session!


A Look Inside a Beating Heart Cell

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Caption: Microtubules (blue) in a beating heart muscle cell, or cardiomyocyte. Credit: Lab of Ben Prosser, Ph.D., Perelman School of Medicine, University of Pennsylvania

You might expect that scientists already know everything there is to know about how a healthy heart beats. But researchers have only recently had the tools to observe some of the dynamic inner workings of heart cells as they beat. Now an NIH-funded team has captured video to show that a component of a heart muscle cell called microtubules—long thought to be very rigid—serve an unexpected role as molecular shock absorbers.

As described for the first time recently in the journal Science, the microtubules buckle under the force of each contraction of the muscle cell before springing back to their original length and form. The team also details a biochemical process that allows a cell to fine-tune the level of resistance that the microtubules provide. The findings have important implications for understanding not only the mechanics of a healthy beating heart, but how the abnormal stiffening of heart cells might play a role in various forms of cardiac disease.


Snapshots of Life: Green Eggs and Heart Valves

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three-day old chicken embryo

Credit: Jessica Ryvlin, Stephanie Lindsey, and Jonathan Butcher, Cornell University, Ithaca, NY

What might appear in this picture to be an exotic, green glow worm served up on a collard leaf actually comes from something we all know well: an egg. It’s a 3-day-old chicken embryo that’s been carefully removed from its shell, placed in a special nutrient-rich bath to keep it alive, and then photographed through a customized stereo microscope. In the middle of the image, just above the blood vessels branching upward, you can see the outline of a transparent, developing eye. Directly to the left is the embryonic heart, which at this early stage is just a looped tube not yet with valves or pumping chambers.

Developing chicks are one of the most user-friendly models for studying normal and abnormal heart development. Human and chick hearts have a lot in common structurally, with four chambers and four valves pumping two circulations of blood in parallel. Unlike mammalian embryos tucked away in the womb, researchers have free range to study the chick heart in or out of the egg as it develops from a simple looped tube to a four-chambered organ.

Jonathan Butcher and his NIH-supported research group at Cornell University, Ithaca, NY, snapped this photo, a winner in the Federation of American Societies for Experimental Biology’s 2015 BioArt competition, to monitor differences in blood flow through the developing chick heart. You can get a sense of these differences by the varying intensities of green fluorescence in the blood vessels. The Butcher lab is interested in understanding how the force of the blood flow triggers the switching on and off of genes responsible for making functional heart valves. Although the four valves aren’t yet visible in this image, they will soon elongate into flap-like structures that open and close to begin regulating the normal flow of blood through the heart.


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