3D imaging shows how shark guts work like Tesla valves


Born in Serbia in 1920 inventor Nikola Tesla Designed and obtained what he called “Valve catheter”: A pipe whose internal design ensures that fluid flows in a preferred direction without moving parts, making it ideal for microfluidic applications and other uses.according to A recent paper published in Proceedings of the Royal Society BThe Tesla valve also provides a useful model for how food passes through the digestive systems of many sharks.Based on a new CT scan of the shark’s intestines, scientists have concluded that the intestine is formed naturally Tesla valve.

“It’s time to use some modern technology to observe these truly amazing shark spiral intestines,” Co-author Samantha Leigh says California State University Dominguez Hills. “We have developed a new method to digitally scan these tissues, and now it is possible to observe soft tissues in great detail without having to slice them.”

The key to Tesla’s ingenious valve design is a set of interconnected, asymmetric, teardrop-like circuits.exist His patent applicationTesla described the series of 11 flow control segments as “composed of enlarged, recessed, protruding, baffle or barrel, although in addition to surface friction, there is almost no resistance to the passage of fluid in one direction, but It almost constitutes an insurmountable obstacle for it to flow in the opposite direction.” And because it achieves this without moving parts, the Tesla valve is more resistant to wear from frequent operations.

Tesla claims that the water flowing through his valve in one direction is 200 times slower than the other, which may be an exaggeration.A team of scientists from New York University A working Tesla valve was built in 2021According to the inventor’s design, the claim was tested by measuring the water flow through the valve in two directions under different pressures. Scientists have discovered that the flow of water in non-preferred directions is only about twice slower.

However, the flow rate Proved to be a key factorThe valve provides very little resistance at low flow rates, but once the rate increases above a certain threshold, the resistance of the valve will also increase, resulting in reverse turbulence, causing the pipeline to be “blocked” by eddy currents and destructive currents. Therefore, according to co-author Leif Ristroph, it is actually more like a switch and can also help smooth the flow of pulses, similar to how an AC/DC converter converts alternating current to direct current. In fact, Ristoph thinks this may be Tesla’s intention to design the valve, because his greatest reputation is the invention of AC motors and AC/DC converters.

Now, Tesla Valve is gaining insight into the unusual structure of shark intestines, thanks to a team of researchers from three universities: CSU, Dominguez Hills; the University of Washington; and the University of California, Irvine.

shark It is a top predator and feeds on a variety of species, so it is important for controlling biodiversity in a larger ecosystem. Most sharks have a spiral intestine, which is composed of a different number of folds in the intestinal tissue, and is usually one of four basic structures: columnar, curled, funnel directed toward the back, or funnel directed toward the front. These four types of intestines are usually depicted in 2D sketches, which are expanded in two dimensions after anatomy, or are imaged into two-dimensional slices through three-dimensional structure imaging. But this did not give scientists insight into how the structure works in situ.

Last year, Japanese researchers Reconstructed micrographs of tissue sections According to the author of this latest paper, from a cat shark to a three-dimensional model, it provides “a tempting glimpse of the anatomical structure of the scroll-shaped spiral intestine.” Adam Summers, a co-author of the Friday Harbor Laboratory at the University of Washington, and his colleagues believe that CT scans might accomplish a similar thing because the technique involves taking a series of X-ray images from different angles and then combining them into a 3D image. picture.


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