stiffness

Stiffness

Stiffness variance

Just a little stiffness. That's all.

Here you've got the aortic valve.

We call that the aortic arch.

That's not guessing. The child has a fever, headache, stiffness.

That external aortic root, it will never work, you know.

So I set out to change the entire treatment for aortic dilation.

You can see two of the leaflets of the aortic valve working there.

It has a funny tri lobal shape at the bottom, which contains the aortic valve.

So when you have dub, you have noise coming from the pulmonic and the aortic valve snapping shut.

You can see how the pulmonary and aortic valve are closed when the mitral and tricuspid valve are open.

In the middle, you can see that little structure squeezing out, that's the left ventricle, pushing blood out through the aortic valve.

like Richard, or a cockroach, or a crab, or a kangaroo, the relative leg stiffness of that spring is the same for everything we've seen so far.

And then the final valve, I need to find a nice spot to write it maybe to right here, this final valve that passes through is called the Aortic valve.

If you compare our new treatment to the existing alternative, the composite aortic root graft, there are one or two startling comparisons which I'm sure will be clear to all of you.

What's happening between these two, time like here, is that blood is actually squeezing out because the pulmonic and aortic valves just opened, blood is squeezing out and going to the whole body.

But you also know that if that is what's making the noise, you can kind of guess, and it's a smart guess that at the same time the pulmonic and the aortic valve just opened.

It's an observation with obvious medical applications in humans as well, but it's also relevant in a broad sense, I think, to the design of prosthetics, soft robots, basically anything where changes of shape and stiffness are important.

So if you're ever thinking about the issue of compliance, when we're talking about stiffness, think about these curves and the fact that where the slope is tells you how compliant something is, and that arteries are going to be more compliant than a stiff pipe, certainly, but less compliant than the veins.

This painting is often compared to an early renaissance painting by Raphael's teacher Perugino The Giving of the Keys to Saint Peter and you can begin to see here in this early work by Raphael indications of what we understand now as the high renaissance style as opposed to the kind of stiffness of the 15th century of the early renaissance.