Perimeter institute for Theoretical Physics (located in Waterloo, Ontario, Canada) is presenting one of its public lectures according to a March 31, 2023 PI announcement (received via email),
The Jazz of Physics FRIDAY, APRIL 14  at 7:00 pm ET Stephon Alexander, Brown University
Take a musical journey of the mind and the cosmos with scientist and musician Stephon Alexander. A professor of physics at Brown University, Alexander began his journey to science in high school, where a teacher introduced him to the magic of jazz, fostering a connection between John Coltrane and Albert Einstein.
In his April 14  lecture, Alexander will demonstrate how the search for answers to deep cosmological puzzles has parallels to jazz improvisation. He will also explore new ways that music, particularly jazz, mirrors concepts in modern physics such as quantum mechanics, general relativity, and the early universe.
The Black Hole Bistro will not be available for dinner service the evening of the event.
Don’t forget to try to sign into your PI account before Monday morning, so you are ready when tickets go on sale.
If you didn’t get tickets for the lecture, not to worry – you can always catch the livestream on Inside the Perimeter or watch it on YouTube after the fact.
I checked and, at this point, you have to go on a waiting list for tickets. Here’s more about the process and your other options, from the The Jazz of Physics event page,
Waiting Line On the night of the lecture, there will be a waiting line at Perimeter for last minute cancelled tickets. Come to Perimeter after 6:00 PM and pick up a waiting line chit from the ticket table. While you wait, participate in pre-lecture activities. An announcement will be made in the Atrium at 6:50 PM if theatre seats are available. Note: You must arrive in person to be part of the waiting line, and be in the Atrium when the announcement is made.
No Disappointments Everyone who comes to Perimeter will be able to enjoy this lecture. If you do not manage to obtain a theatre ticket, you can join our waiting line and watch live from the quiet of the Time Room.
All of our lectures are streamed live. You can watch the live stream of this lecture here [not yet active; check on day of event], or watch the recordings at your leisure on our YouTube Channel.
Stephon Alexander has his own website here where you’ll find (amongst other things like his TEDx talk and various interviews; he doesn’t seem to have updated the content since 2022) his 2021 book “Fear of a Black Universe; An Outsider’s Guide to the Future of Physics.” You can see what Kirkus Reviews had to say about the book here.
In an important step toward a fully implantable intracortical brain-computer interface system, BrainGate researchers demonstrated human use of a wireless transmitter capable of delivering high-bandwidth neural signals.
Brain-computer interfaces (BCIs) are an emerging assistive technology, enabling people with paralysis to type on computer screens or manipulate robotic prostheses just by thinking about moving their own bodies. For years, investigational BCIs used in clinical trials have required cables to connect the sensing array in the brain to computers that decode the signals and use them to drive external devices.
Now, for the first time, BrainGate clinical trial participants with tetraplegia have demonstrated use of an intracortical wireless BCI with an external wireless transmitter. The system is capable of transmitting brain signals at single-neuron resolution and in full broadband fidelity without physically tethering the user to a decoding system. The traditional cables are replaced by a small transmitter about 2 inches in its largest dimension and weighing a little over 1.5 ounces. The unit sits on top of a user’s head and connects to an electrode array within the brain’s motor cortex using the same port used by wired systems.
For a study published in IEEE Transactions on Biomedical Engineering, two clinical trial participants with paralysis used the BrainGate system with a wireless transmitter to point, click and type on a standard tablet computer. The study showed that the wireless system transmitted signals with virtually the same fidelity as wired systems, and participants achieved similar point-and-click accuracy and typing speeds.
“We’ve demonstrated that this wireless system is functionally equivalent to the wired systems that have been the gold standard in BCI performance for years,” said John Simeral, an assistant professor of engineering (research) at Brown University, a member of the BrainGate research consortium and the study’s lead author. “The signals are recorded and transmitted with appropriately similar fidelity, which means we can use the same decoding algorithms we used with wired equipment. The only difference is that people no longer need to be physically tethered to our equipment, which opens up new possibilities in terms of how the system can be used.”
The researchers say the study represents an early but important step toward a major objective in BCI research: a fully implantable intracortical system that aids in restoring independence for people who have lost the ability to move. While wireless devices with lower bandwidth have been reported previously, this is the first device to transmit the full spectrum of signals recorded by an intracortical sensor. That high-broadband wireless signal enables clinical research and basic human neuroscience that is much more difficult to perform with wired BCIs.
The new study demonstrated some of those new possibilities. The trial participants — a 35-year-old man and a 63-year-old man, both paralyzed by spinal cord injuries — were able to use the system in their homes, as opposed to the lab setting where most BCI research takes place. Unencumbered by cables, the participants were able to use the BCI continuously for up to 24 hours, giving the researchers long-duration data including while participants slept.
“We want to understand how neural signals evolve over time,” said Leigh Hochberg, an engineering professor at Brown, a researcher at Brown’s Carney Institute for Brain Science and leader of the BrainGate clinical trial. “With this system, we’re able to look at brain activity, at home, over long periods in a way that was nearly impossible before. This will help us to design decoding algorithms that provide for the seamless, intuitive, reliable restoration of communication and mobility for people with paralysis.”
The device used in the study was first developed at Brown in the lab of Arto Nurmikko, a professor in Brown’s School of Engineering. Dubbed the Brown Wireless Device (BWD), it was designed to transmit high-fidelity signals while drawing minimal power. In the current study, two devices used together recorded neural signals at 48 megabits per second from 200 electrodes with a battery life of over 36 hours.
While the BWD has been used successfully for several years in basic neuroscience research, additional testing and regulatory permission were required prior to using the system in the BrainGate trial. Nurmikko says the step to human use marks a key moment in the development of BCI technology.
“I am privileged to be part of a team pushing the frontiers of brain-machine interfaces for human use,” Nurmikko said. “Importantly, the wireless technology described in our paper has helped us to gain crucial insight for the road ahead in pursuit of next generation of neurotechnologies, such as fully implanted high-density wireless electronic interfaces for the brain.”
The new study marks another significant advance by researchers with the BrainGate consortium, an interdisciplinary group of researchers from Brown, Stanford and Case Western Reserve universities, as well as the Providence Veterans Affairs Medical Center and Massachusetts General Hospital. In 2012, the team published landmark research in which clinical trial participants were able, for the first time, to operate multidimensional robotic prosthetics using a BCI. That work has been followed by a steady stream of refinements to the system, as well as new clinical breakthroughs that have enabled people to type on computers, use tablet apps and even move their own paralyzed limbs.
“The evolution of intracortical BCIs from requiring a wire cable to instead using a miniature wireless transmitter is a major step toward functional use of fully implanted, high-performance neural interfaces,” said study co-author Sharlene Flesher, who was a postdoctoral fellow at Stanford and is now a hardware engineer at Apple. “As the field heads toward reducing transmitted bandwidth while preserving the accuracy of assistive device control, this study may be one of few that captures the full breadth of cortical signals for extended periods of time, including during practical BCI use.”
The new wireless technology is already paying dividends in unexpected ways, the researchers say. Because participants are able to use the wireless device in their homes without a technician on hand to maintain the wired connection, the BrainGate team has been able to continue their work during the COVID-19 pandemic.
“In March 2020, it became clear that we would not be able to visit our research participants’ homes,” said Hochberg, who is also a critical care neurologist at Massachusetts General Hospital and director of the V.A. Rehabilitation Research and Development Center for Neurorestoration and Neurotechnology. “But by training caregivers how to establish the wireless connection, a trial participant was able to use the BCI without members of our team physically being there. So not only were we able to continue our research, this technology allowed us to continue with the full bandwidth and fidelity that we had before.”
Simeral noted that, “Multiple companies have wonderfully entered the BCI field, and some have already demonstrated human use of low-bandwidth wireless systems, including some that are fully implanted. In this report, we’re excited to have used a high-bandwidth wireless system that advances the scientific and clinical capabilities for future systems.”
Brown has a licensing agreement with Blackrock Microsystems to make the device available to neuroscience researchers around the world. The BrainGate team plans to continue to use the device in ongoing clinical trials.
Carbon nanotubes, buckminsterfullerenes (also known as, buckyballs), and/or graphene are names for different carbon nanoscale structures and, as far as I’m aware,carbon is the only element that merits some distinct names at the nanoscale. By comparison, gold can be gold nanorods, gold nanostars, gold nanoparticles, and so on. In short, nanostructures made of gold (and most other elements) are always prefaced with the word ‘gold’ followed by a word with ‘nano’ in it.
Scientists naming a new boron nanoscale structure seem to have adopted both strategies for a hybrid name. Here’s more from a June 25, 2020 news item on phys.org,
The discovery of carbon nanostructures like two-dimensional graphene and soccer ball-shaped buckyballs helped to launch a nanotechnology revolution. In recent years, researchers from Brown University [located in Rhode Island, US] and elsewhere have shown that boron, carbon’s neighbor on the periodic table, can make interesting nanostructures too, including two-dimensional borophene and a buckyball-like hollow cage structure called borospherene.
Now, researchers from Brown and Tsinghua University have added another boron nanostructure to the list. In a paper published in Nature Communications, they show that clusters of 18 boron atoms and three atoms of lanthanide elements form a bizarre cage-like structure unlike anything they’ve ever seen.
“This is just not a type of structure you expect to see in chemistry,” said Lai-Sheng Wang, a professor of chemistry at Brown and the study’s senior author. “When we wrote the paper we really struggled to describe it. It’s basically a spherical trihedron. Normally you can’t have a closed three-dimensional structure with only three sides, but since it’s spherical, it works.”
The researchers are hopeful that the nanostructure may shed light on the bulk structure and chemical bonding behavior of boron lanthanides, an important class of materials widely used in electronics and other applications. The nanostructure by itself may have interesting properties as well, the researchers say.
“Lanthanide elements are important magnetic materials, each with very different magnetic moments,” Wang said. “We think any of the lanthanides will make this structure, so they could have very interesting magnetic properties.”
Wang and his students created the lanthanide-boron clusters by focusing a powerful laser onto a solid target made of a mixture of boron and a lanthanide element. The clusters are formed upon cooling of the vaporized atoms. Then they used a technique called photoelectron spectroscopy to study the electronic properties of the clusters. The technique involves zapping clusters of atoms with another high-powered laser. Each zap knocks an electron out of the cluster. By measuring the kinetic energies of those freed electrons, researchers can create a spectrum of binding energies for the electrons that bond the cluster together.
“When we see a simple, beautiful spectrum, we know there’s a beautiful structure behind it,” Wang said.
To figure out what that structure looks like, Wang compared the photoelectron spectra with theoretical calculations done by Professor Jun Li and his students from Tsinghua. Once they find a theoretical structure with a binding spectrum that matches the experiment, they know they’ve found the right structure.
“This structure was something we never would have predicted,” Wang said. “That’s the value of combining theoretical calculation with experimental data.”
Wang and his colleagues have dubbed the new structures metallo-borospherenes, and they’re hopeful that further research will reveal their properties.
Here’s a link to and a citation for the paper,
Spherical trihedral metallo-borospherenes by Teng-Teng Chen, Wan-Lu Li, Wei-Jia Chen, Xiao-Hu Yu, Xin-Ran Dong, Jun Li & Lai-Sheng Wang. Nature Communications volume 11, Article number: 2766 (2020) DOI: https://doi.org/10.1038/s41467-020-16532-x Published: 02 June 2020
The celebrated painter Jackson Pollock created his most iconic works not with a brush, but by pouring paint onto the canvas from above, weaving sinuous filaments of color into abstract masterpieces. A team of researchers analyzing the physics of Pollock’s technique has shown that the artist had a keen understanding of a classic phenomenon in fluid dynamics — whether he was aware of it or not.
In a paper published in the journal PLOS ONE, the researchers show that Pollock’s technique seems to intentionally avoid what’s known as coiling instability — the tendency of a viscous fluid to form curls and coils when poured on a surface.
“Like most painters, Jackson Pollock went through a long process of experimentation in order to perfect his technique,” said Roberto Zenit, a professor in Brown’s School of Engineering and senior author on the paper. “What we were trying to do with this research is figure out what conclusions Pollock reached in order to execute his paintings the way he wanted. Our main finding in this paper was that Pollock’s movements and the properties of his paints were such he avoided this coiling instability.”
Pollock’s technique typically involved pouring paint straight from a can or along a stick onto a canvas lying horizontally on the floor. It’s often referred to as the “drip technique,” but that’s a bit of a misnomer in the parlance of fluid mechanics, Zenit says. In fluid mechanics, “dripping” would be dispensing the fluid in a way that makes discrete droplets on the canvas. Pollock largely avoided droplets, in favor of unbroken filaments of paint stretching across the canvas.
In order to understand exactly how the technique worked, Zenit and colleagues from the Universidad Nacional Autonoma de Mexico analyzed extensive video of Pollock at work, taking careful measure of how fast he moved and how far from the canvas he poured his paints. Having gathered data on how Pollock worked, the researchers used an experimental setup to recreate his technique. Using the setup, the researchers could deposit paint using a syringe mounted at varying heights onto a canvas moving at varying speeds. The experiments helped to zero in on the most important aspects of what Pollock was doing.
“We can vary one thing at a time so we can decipher the key elements of the technique,” Zenit said. “For example, we could vary the height from which the paint is poured and keep the speed constant to see how that changes things.”
The researchers found that the combination of Pollock’s hand speed, the distance he maintained from the canvas and the viscosity of his paint seem to be aimed at avoiding coiling instability. Anyone who’s ever poured a viscous fluid — perhaps some honey on toast — has likely seen some coiling instability. When a small amount of a viscous fluid is poured, it tends to stack up like a coil of rope before oozing across the surface.
In the context of Pollock’s technique, the instability can result in paint filaments making pigtail-like curls when poured from the can. Some prior research had concluded that that the curved lines in Pollock’s paintings were a result of this instability, but this latest research shows the opposite.
“What we found is that he moved his hand at a sufficiently high speed and a sufficiently short height such that this coiling would not occur,” Zenit said.
Zenit says the findings could be useful in authenticating Pollock’s works. Too many tight curls might suggest that a drip-style painting is not a Pollock. The work could also inform other settings in which viscous fluids are stretched into filaments, such as the manufacture of fiber optics. But Zenit says his main interest in the work is that it’s simply a fascinating way to explore interesting questions in fluid mechanics.
“I consider myself to be a fluid mechanics messenger,” he said. “This is my excuse to talk science. It’s fascinating to see that painters are really fluid mechanicians, even though they may not know it.”
I could not find any videos related to this research that I know how to embed but Palacios, Zetina, and Zenit have investigated Polock’s ‘physics’ before,
If you want to see Pollock dripping his painting in action, there’s a 10 min. 13 secs. film made in 1950 (Note: Links have been removed from text; link to 10 min. film is below),
In the summer of 1950, Hans Namuth approached Jackson Pollock and asked the abstract expressionist painter if he could photograph him in his studio, working with his “drip” technique of painting. When Namuth arrived, he found:
“A dripping wet canvas covered the entire floor. Blinding shafts of sunlight hit the wet canvas, making its surface hard to see. There was complete silence…. Pollock looked at the painting. Then unexpectedly, he picked up can and paintbrush and started to move around the canvas. It was as if he suddenly realized the painting was not finished. His movements, slow at first, gradually became faster and more dancelike as he flung black, white and rust-colored paint onto the canvas.”
The images from this shoot “helped transform Pollock from a talented, cranky loner into the first media-driven superstar of American contemporary art, the jeans-clad, chain-smoking poster boy of abstract expressionism,” one critic later wrote in The Washington Post.
You can find the film and accompanying Open Culture text intact with links here.
A new software system developed by Brown University [US] researchers turns cell phones into augmented reality portals, enabling users to place virtual building blocks, furniture and other objects into real-world backdrops, and use their hands to manipulate those objects as if they were really there.
The developers hope the new system, called Portal-ble, could be a tool for artists, designers, game developers and others to experiment with augmented reality (AR). The team will present the work later this month at the ACM Symposium on User Interface Software and Technology (UIST 2019) in New Orleans. The source code for Andriod is freely available for download on the researchers’ website, and iPhone code will follow soon.
“AR is going to be a great new mode of interaction,” said Jeff Huang, an assistant professor of computer science at Brown who developed the system with his students. “We wanted to make something that made AR portable so that people could use anywhere without any bulky headsets. We also wanted people to be able to interact with the virtual world in a natural way using their hands.”
Huang said the idea for Portal-ble’s “hands-on” interaction grew out of some frustration with AR apps like Pokemon GO. AR apps use smartphones to place virtual objects (like Pokemon characters) into real-world scenes, but interacting with those objects requires users to swipe on the screen.
“Swiping just wasn’t a satisfying way of interacting,” Huang said. “In the real world, we interact with objects with our hands. We turn doorknobs, pick things up and throw things. So we thought manipulating virtual objects by hand would be much more powerful than swiping. That’s what’s different about Portal-ble.”
The platform makes use of a small infrared sensor mounted on the back of a phone. The sensor tracks the position of people’s hands in relation to virtual objects, enabling users to pick objects up, turn them, stack them or drop them. It also lets people use their hands to virtually “paint” onto real-world backdrops. As a demonstration, Huang and his students used the system to paint a virtual garden into a green space on Brown’s College Hill campus.
Huang says the main technical contribution of the work was developing the right accommodations and feedback tools to enable people to interact intuitively with virtual objects.
“It turns out that picking up a virtual object is really hard if you try to apply real-world physics,” Huang said. “People try to grab in the wrong place, or they put their fingers through the objects. So we had to observe how people tried to interact with these objects and then make our system able accommodate those tendencies.”
To do that, Huang enlisted students in a class he was teaching to come up with tasks they might want to do in the AR world — stacking a set of blocks, for example. The students then asked other people to try performing those tasks using Portal-ble, while recording what people were able to do and what they couldn’t. They could then adjust the system’s physics and user interface to make interactions more successful.
“It’s a little like what happens when people draw lines in Photoshop,” Huang said. “The lines people draw are never perfect, but the program can smooth them out and make them perfectly straight. Those were the kinds of accommodations we were trying to make with these virtual objects.”
The team also added sensory feedback — visual highlights on objects and phone vibrations — to make interactions easier. Huang said he was somewhat surprised that phone vibrations helped users to interact. Users feel the vibrations in the hand they’re using to hold the phone, not in the hand that’s actually grabbing for the virtual object. Still, Huang said, vibration feedback still helped users to more successfully interact with objects.
In follow-up studies, users reported that the accommodations and feedback used by the system made tasks significantly easier, less time-consuming and more satisfying.
Huang and his students plan to continue working with Portal-ble — expanding its object library, refining interactions and developing new activities. They also hope to streamline the system to make it run entirely on a phone. Currently the infrared sensor requires an infrared sensor and external compute stick for extra processing power.
Huang hopes people will download the freely available source code and try it for themselves. “We really just want to put this out there and see what people do with it,” he said. “The code is on our website for people to download, edit and build off of. It will be interesting to see what people do with it.
Co-authors on the research paper were Jing Qian, Jiaju Ma, Xiangyu Li, Benjamin Attal, Haoming Lai, James Tompkin and John Hughes. The work was supported by the National Science Foundation (IIS-1552663) and by a gift from Pixar.
This is the first time I’ve seen an augmented reality system that seems accessible, i.e., affordable. You can find out more on the Portal-ble ‘resource’ page where you’ll also find a link to the source code repository. The researchers, as noted in the news release, have an Android version available now with an iPhone version to be released in the future.
The debate takes place in New York City on Thursday, January 31, 2019. Ticket prices and more follow in the information from the January 17, 2019 IQ2US (Intelligence Squared) debates announcement received via email,
Intelligence Squared U.S. Debates De-Extinction, in NYC and Online January 31 
While bringing extinct species back to life was once a sci-fi fantasy out of ‘Jurassic Park’, recent biological and technological breakthroughs indicate that reviving creatures like the woolly mammoth and the passenger pigeon could someday become a reality. De-extinction’s proponents argue that benefits include correcting mistakes of the past and helping to curb climate change. But others aren’t so sure de-extinction is ethical, or even feasible, they worry that the resources channeled to support de-extinction efforts could compete with current work to save the over 16,000 endangered species on Earth today. On Thursday, January 31, veteran debate series Intelligence Squared U.S. continues their explorations into science and technology with a live debate on the motion “Don’t Bring Extinct Creatures Back to Life.” Environmentalist Stewart Brand, who founded the Whole Earth Catalog, and Harvard professor Dr. George Church, who is working to revive the woolly mammoth, will argue in favor of de-extinction. Debating against them and against de-extinction will be Dr. Ross MacPhee, curator at the American Museum of Natural History, and evolutionary biologist Dr. Lynn J. Rothschild, a senior scientist at NASA’s Ames Research Center.
The debate will be held at NYC’s Kaye Playhouse and stream live online, then air soon after as part of the syndicated public radio show and podcast “Intelligence Squared U.S.” On January 31 , online viewers can tune in at IQ2US’s website: https://www.intelligencesquaredus.org
WHAT: Intelligence Squared U.S. Debates “Don’t Bring Extinct Creatures Back to Life”
WHEN: Thursday, January 31 / 7:00-8:30 PM EDT
WHERE: The Kaye Playhouse at Hunter College, 115 E. 68th Street, New York, NY
* Dr. Ross MacPhee: Curator, Department of Mammalogy, Division of Vertebrate Zoology, American Museum of Natural History Dr. Ross MacPhee is the former chairman of the Department of Mammalogy at the American Museum of Natural History, where he has been curator since 1988. Known for his paleomammalogical research on island extinctions, he has focused his most recent work on extinctions occurring during the past 50,000 years, or “Near Time.” He is the author of the new book “End of the Megafauna: The Fate of the World’s Hugest, Fiercest, and Strangest Animals” (Norton, 2019). Dr. MacPhee has also collaborated with geneticists and molecular biologists to develop the new tool of “ancient DNA” for studying the ultimate collapse of Pleistocene mammals.
* Dr. Lynn J. Rothschild: Evolutionary Biologist & Astrobiologist Dr. Lynn Rothschild is an evolutionary biologist and astrobiologist who focuses on the origin and evolution of life on Earth, while at the same time pioneering the use of synthetic biology to enable space exploration. She is a senior scientist at NASA’s Ames Research Center as well as an adjunct professor of molecular biology, cell biology, and biochemistry at Brown University. Since 2011, Rothschild has been the faculty adviser of the award-winning Stanford-Brown iGEM team, which has pioneered the use of synthetic biology to accomplish NASA’s missions, including the human settlement of Mars.
Arguing Against the Motion
* Stewart Brand: Co-Founder, Revive & Restore & Founder, Whole Earth Catalog Stewart Brand is a futurist, environmentalist, and proponent of de-extinction who promotes the use of science to preserve the planet. He is the co-founder of Revive & Restore, which facilitates extinct species revival, and the Long Now Foundation, of which he is co-chair and president. He was the founder and editor of the award-winning Whole Earth Catalog and is the author of several books, including “Whole Earth Discipline: An Ecopragmatist Manifesto.” In 2013, Brand organized the TEDxDeExtinction conference in partnership with the National Geographic Society.
* Dr. George Church: Professor of Genetics, Harvard and MIT & Founder, Personal Genome Project Dr. George Church is a geneticist and molecular engineer who is working to revive the extinct woolly mammoth. He is the Robert Winthrop professor of genetics at Harvard Medical School and professor of health sciences and technology at Harvard and MIT. Dr. Church developed methods used for the first genome sequence and founded the Personal Genome Project. He has earned dozens of awards and honors, including Time’s “100 Most Influential People,” and is the author of 490 papers, 130 patent publications, and the book “Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves.”
ABOUT INTELLIGENCE SQUARED U.S. DEBATES (IQ2US) A non-partisan, non-profit organization, Intelligence Squared U.S. was founded in 2006 to address a fundamental problem in America: the extreme polarization of our nation and our politics. Their mission is to restore critical thinking, facts, reason, and civility to American public discourse. The award-winning debate series reaches over 30 million American households through multi-platform distribution, including radio, television, live streaming, podcasts, interactive digital content, and on-demand apps on Roku and Apple TV. With over 150 debates and counting, Intelligence Squared U.S. has encouraged the public to “think twice” on a wide range of provocative topics. Author and ABC News correspondent John Donvan has moderated IQ2US since 2008.
The only speaker who’s been previously mentioned on this blog is George Church. In particular, 2018 seems to have been his year although it’s possible 2019 may beat that record for appearances on this blog.
Etc.: use ‘George Church’ as the search term in the blog search engine for more
Coming January 30, 2019: Watch this spot for a link to the live stream: Here you go on January 31, 2019 at 4 pm PT or 7 pm ET: <iframe width=”560″ height=”315″ src=“https://www.youtube.com/embed/N-1iqmKlTs8” frameborder=”0″ allow=”accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture” allowfullscreen></iframe>
*Removed redundant word ‘back’ from head on February 8, 2022.
It took me a few minutes to figure out why this item about a quadriplegic (also known as, tetraplegic) man is news. After all, I have a May 17, 2012 posting which features a video and information about a quadri(tetra)plegic woman who was drinking her first cup of coffee, independently, in many years. The difference is that she was using an external robotic arm and this man is using *his own arm*,
Bill Kochevar grabbed a mug of water, drew it to his lips and drank through the straw.
His motions were slow and deliberate, but then Kochevar hadn’t moved his right arm or hand for eight years.
And it took some practice to reach and grasp just by thinking about it.
Kochevar, who was paralyzed below his shoulders in a bicycling accident, is believed to be the first person with quadriplegia in the world to have arm and hand movements restored with the help of two temporarily implanted technologies.
A brain-computer interface with recording electrodes under his skull, and a functional electrical stimulation (FES) system* activating his arm and hand, reconnect his brain to paralyzed muscles.
Holding a makeshift handle pierced through a dry sponge, Kochevar scratched the side of his nose with the sponge. He scooped forkfuls of mashed potatoes from a bowl—perhaps his top goal—and savored each mouthful.
“For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me,” said Kochevar, 56, of Cleveland. “It’s better than I thought it would be.”
Kochevar is the focal point of research led by Case Western Reserve University, the Cleveland Functional Electrical Stimulation (FES) Center at the Louis Stokes Cleveland VA Medical Center and University Hospitals Cleveland Medical Center (UH). A study of the work was published in the The Lancet March 28  at 6:30 p.m. U.S. Eastern time.
“He’s really breaking ground for the spinal cord injury community,” said Bob Kirsch, chair of Case Western Reserve’s Department of Biomedical Engineering, executive director of the FES Center and principal investigator (PI) and senior author of the research. “This is a major step toward restoring some independence.”
When asked, people with quadriplegia say their first priority is to scratch an itch, feed themselves or perform other simple functions with their arm and hand, instead of relying on caregivers.
“By taking the brain signals generated when Bill attempts to move, and using them to control the stimulation of his arm and hand, he was able to perform personal functions that were important to him,” said Bolu Ajiboye, assistant professor of biomedical engineering and lead study author.
Technology and training
The research with Kochevar is part of the ongoing BrainGate2* pilot clinical trial being conducted by a consortium of academic and VA institutions assessing the safety and feasibility of the implanted brain-computer interface (BCI) system in people with paralysis. Other investigational BrainGate research has shown that people with paralysis can control a cursor on a computer screen or a robotic arm (braingate.org).
“Every day, most of us take for granted that when we will to move, we can move any part of our body with precision and control in multiple directions and those with traumatic spinal cord injury or any other form of paralysis cannot,” said Benjamin Walter, associate professor of neurology at Case Western Reserve School of Medicine, clinical PI of the Cleveland BrainGate2 trial and medical director of the Deep Brain Stimulation Program at UH Cleveland Medical Center.
“The ultimate hope of any of these individuals is to restore this function,” Walter said. “By restoring the communication of the will to move from the brain directly to the body this work will hopefully begin to restore the hope of millions of paralyzed individuals that someday they will be able to move freely again.”
Jonathan Miller, assistant professor of neurosurgery at Case Western Reserve School of Medicine and director of the Functional and Restorative Neurosurgery Center at UH, led a team of surgeons who implanted two 96-channel electrode arrays—each about the size of a baby aspirin—in Kochevar’s motor cortex, on the surface of the brain.
The arrays record brain signals created when Kochevar imagines movement of his own arm and hand. The brain-computer interface extracts information from the brain signals about what movements he intends to make, then passes the information to command the electrical stimulation system.
To prepare him to use his arm again, Kochevar first learned how to use his brain signals to move a virtual-reality arm on a computer screen.
“He was able to do it within a few minutes,” Kirsch said. “The code was still in his brain.”
As Kochevar’s ability to move the virtual arm improved through four months of training, the researchers believed he would be capable of controlling his own arm and hand.
Miller then led a team that implanted the FES systems’ 36 electrodes that animate muscles in the upper and lower arm.
The BCI decodes the recorded brain signals into the intended movement command, which is then converted by the FES system into patterns of electrical pulses.
The pulses sent through the FES electrodes trigger the muscles controlling Kochevar’s hand, wrist, arm, elbow and shoulder. To overcome gravity that would otherwise prevent him from raising his arm and reaching, Kochevar uses a mobile arm support, which is also under his brain’s control.
Eight years of muscle atrophy required rehabilitation. The researchers exercised Kochevar’s arm and hand with cyclical electrical stimulation patterns. Over 45 weeks, his strength, range of motion and endurance improved. As he practiced movements, the researchers adjusted stimulation patterns to further his abilities.
Kochevar can make each joint in his right arm move individually. Or, just by thinking about a task such as feeding himself or getting a drink, the muscles are activated in a coordinated fashion.
When asked to describe how he commanded the arm movements, Kochevar told investigators, “I’m making it move without having to really concentrate hard at it…I just think ‘out’…and it goes.”
Kocehvar is fitted with temporarily implanted FES technology that has a track record of reliable use in people. The BCI and FES system together represent early feasibility that gives the research team insights into the potential future benefit of the combined system.
Advances needed to make the combined technology usable outside of a lab are not far from reality, the researchers say. Work is underway to make the brain implant wireless, and the investigators are improving decoding and stimulation patterns needed to make movements more precise. Fully implantable FES systems have already been developed and are also being tested in separate clinical research.
Kochevar welcomes new technology—even if it requires more surgery—that will enable him to move better. “This won’t replace caregivers,” he said. “But, in the long term, people will be able, in a limited way, to do more for themselves.”
Bill Kochevar, 53, has had electrical implants in the motor cortex of his brain and sensors inserted in his forearm, which allow the muscles of his arm and hand to be stimulated in response to signals from his brain, decoded by computer. After eight years, he is able to drink and feed himself without assistance.
“I think about what I want to do and the system does it for me,” Kochevar told the Guardian. “It’s not a lot of thinking about it. When I want to do something, my brain does what it does.”
The experimental technology, pioneered by the Case Western Reserve University in Cleveland, Ohio, is the first in the world to restore brain-controlled reaching and grasping in a person with complete paralysis.
For now, the process is relatively slow, but the scientists behind the breakthrough say this is proof of concept and that they hope to streamline the technology until it becomes a routine treatment for people with paralysis. In the future, they say, it will also be wireless and the electrical arrays and sensors will all be implanted under the skin and invisible.
Although only tested with one participant, the study is a major advance and the first to restore brain-controlled reaching and grasping in a person with complete paralysis. The technology, which is only for experimental use in the USA, circumvents rather than repairs spinal injuries, meaning the participant relies on the device being implanted and switched on to move.
“Our research is at an early stage, but we believe that this neuro-prosthesis could offer individuals with paralysis the possibility of regaining arm and hand functions to perform day-to-day activities, offering them greater independence,” said lead author Dr Bolu Ajiboye, Case Western Reserve University, USA. “So far it has helped a man with tetraplegia to reach and grasp, meaning he could feed himself and drink. With further development, we believe the technology could give more accurate control, allowing a wider range of actions, which could begin to transform the lives of people living with paralysis.” 
Previous research has used similar elements of the neuro-prosthesis. For example, a brain-computer interface linked to electrodes on the skin has helped a person with less severe paralysis open and close his hand, while other studies have allowed participants to control a robotic arm using their brain signals. However, this is the first to restore reaching and grasping via the system in a person with a chronic spinal cord injury.
In this study, a 53 year-old man who had been paralysed below the shoulders for eight years underwent surgery to have the neuro-prosthesis fitted.
This involved brain surgery to place sensors in the motor cortex area of his brain responsible for hand movement – creating a brain-computer interface that learnt which movements his brain signals were instructing for. This initial stage took four months and included training using a virtual reality arm.
He then underwent another procedure placing 36 muscle stimulating electrodes into his upper and lower arm, including four that helped restore finger and thumb, wrist, elbow and shoulder movements. These were switched on 17 days after the procedure, and began stimulating the muscles for eight hours a week over 18 weeks to improve strength, movement and reduce muscle fatigue.
The researchers then wired the brain-computer interface to the electrical stimulators in his arm, using a decoder (mathematical algorithm) to translate his brain signals into commands for the electrodes in his arm. The electrodes stimulated the muscles to produce contractions, helping the participant intuitively complete the movements he was thinking of. The system also involved an arm support to stop gravity simply pulling his arm down.
During his training, the participant described how he controlled the neuro-prosthesis: “It’s probably a good thing that I’m making it move without having to really concentrate hard at it. I just think ‘out’ and it just goes.”
After 12 months of having the neuro-prosthesis fitted, the participant was asked to complete day-to-day tasks, including drinking a cup of coffee and feeding himself. First of all, he observed while his arm completed the action under computer control. During this, he thought about making the same movement so that the system could recognise the corresponding brain signals. The two systems were then linked and he was able to use it to drink a coffee and feed himself.
He successfully drank in 11 out of 12 attempts, and it took him roughly 20-40 seconds to complete the task. When feeding himself, he did so multiple times – scooping forkfuls of food and navigating his hand to his mouth to take several bites.
“Although similar systems have been used before, none of them have been as easy to adopt for day-to-day use and they have not been able to restore both reaching and grasping actions,” said Dr Ajiboye. “Our system builds on muscle stimulating electrode technology that is already available and will continue to improve with the development of new fully implanted and wireless brain-computer interface systems. This could lead to enhanced performance of the neuro-prosthesis with better speed, precision and control.” 
At the time of the study, the participant had had the neuro-prosthesis implanted for almost two years (717 days) and in this time experienced four minor, non-serious adverse events which were treated and resolved.
Despite its achievements, the neuro-prosthesis still had some limitations, including that movements made using it were slower and less accurate than those made using the virtual reality arm the participant used for training. When using the technology, the participant also needed to watch his arm as he lost his sense of proprioception – the ability to intuitively sense the position and movement of limbs – as a result of the paralysis.
Writing in a linked Comment, Dr Steve Perlmutter, University of Washington, USA, said: “The goal is futuristic: a paralysed individual thinks about moving her arm as if her brain and muscles were not disconnected, and implanted technology seamlessly executes the desired movement… This study is groundbreaking as the first report of a person executing functional, multi-joint movements of a paralysed limb with a motor neuro-prosthesis. However, this treatment is not nearly ready for use outside the lab. The movements were rough and slow and required continuous visual feedback, as is the case for most available brain-machine interfaces, and had restricted range due to the use of a motorised device to assist shoulder movements… Thus, the study is a proof-of-principle demonstration of what is possible, rather than a fundamental advance in neuro-prosthetic concepts or technology. But it is an exciting demonstration nonetheless, and the future of motor neuro-prosthetics to overcome paralysis is brighter.”
 Quote direct from author and cannot be found in the text of the Article.
This high-resolution transmission electron micrograph of particles made by the research team shows the particles’ highly uniform size and shape. These are iron oxide particles just 3 nanometers across, coated with a zwitterion layer. Their small size means they can easily be cleared through the kidneys after injection. Courtesy of the researchers
A new, specially coated iron oxide nanoparticle developed by a team at MIT [Massachusetts Institute of Technology] and elsewhere could provide an alternative to conventional gadolinium-based contrast agents used for magnetic resonance imaging (MRI) procedures. In rare cases, the currently used gadolinium agents have been found to produce adverse effects in patients with impaired kidney function.
The advent of MRI technology, which is used to observe details of specific organs or blood vessels, has been an enormous boon to medical diagnostics over the last few decades. About a third of the 60 million MRI procedures done annually worldwide use contrast-enhancing agents, mostly containing the element gadolinium. While these contrast agents have mostly proven safe over many years of use, some rare but significant side effects have shown up in a very small subset of patients. There may soon be a safer substitute thanks to this new research.
In place of gadolinium-based contrast agents, the researchers have found that they can produce similar MRI contrast with tiny nanoparticles of iron oxide that have been treated with a zwitterion coating. (Zwitterions are molecules that have areas of both positive and negative electrical charges, which cancel out to make them neutral overall.) The findings are being published this week in the Proceedings of the National Academy of Sciences, in a paper by Moungi Bawendi, the Lester Wolfe Professor of Chemistry at MIT; He Wei, an MIT postdoc; Oliver Bruns, an MIT research scientist; Michael Kaul at the University Medical Center Hamburg-Eppendorf in Germany; and 15 others.
Contrast agents, injected into the patient during an MRI procedure and designed to be quickly cleared from the body by the kidneys afterwards, are needed to make fine details of organ structures, blood vessels, and other specific tissues clearly visible in the images. Some agents produce dark areas in the resulting image, while others produce light areas. The primary agents for producing light areas contain gadolinium.
Iron oxide particles have been largely used as negative (dark) contrast agents, but radiologists vastly prefer positive (light) contrast agents such as gadolinium-based agents, as negative contrast can sometimes be difficult to distinguish from certain imaging artifacts and internal bleeding. But while the gadolinium-based agents have become the standard, evidence shows that in some very rare cases they can lead to an untreatable condition called nephrogenic systemic fibrosis, which can be fatal. In addition, evidence now shows that the gadolinium can build up in the brain, and although no effects of this buildup have yet been demonstrated, the FDA is investigating it for potential harm.
“Over the last decade, more and more side effects have come to light” from the gadolinium agents, Bruns says, so that led the research team to search for alternatives. “None of these issues exist for iron oxide,” at least none that have yet been detected, he says.
The key new finding by this team was to combine two existing techniques: making very tiny particles of iron oxide, and attaching certain molecules (called surface ligands) to the outsides of these particles to optimize their characteristics. The iron oxide inorganic core is small enough to produce a pronounced positive contrast in MRI, and the zwitterionic surface ligand, which was recently developed by Wei and coworkers in the Bawendi research group, makes the iron oxide particles water-soluble, compact, and biocompatible.
The combination of a very tiny iron oxide core and an ultrathin ligand shell leads to a total hydrodynamic diameter of 4.7 nanometers, below the 5.5-nanometer renal clearance threshold. This means that the coated iron oxide should quickly clear through the kidneys and not accumulate. This renal clearance property is an important feature where the particles perform comparably to gadolinium-based contrast agents.
Now that initial tests have demonstrated the particles’ effectiveness as contrast agents, Wei and Bruns say the next step will be to do further toxicology testing to show the particles’ safety, and to continue to improve the characteristics of the material. “It’s not perfect. We have more work to do,” Bruns says. But because iron oxide has been used for so long and in so many ways, even as an iron supplement, any negative effects could likely be treated by well-established protocols, the researchers say. If all goes well, the team is considering setting up a startup company to bring the material to production.
For some patients who are currently excluded from getting MRIs because of potential side effects of gadolinium, the new agents “could allow those patients to be eligible again” for the procedure, Bruns says. And, if it does turn out that the accumulation of gadolinium in the brain has negative effects, an overall phase-out of gadolinium for such uses could be needed. “If that turned out to be the case, this could potentially be a complete replacement,” he says.
Ralph Weissleder, a physician at Massachusetts General Hospital who was not involved in this work, says, “The work is of high interest, given the limitations of gadolinium-based contrast agents, which typically have short vascular half-lives and may be contraindicated in renally compromised patients.”
The research team included researchers in MIT’s chemistry, biological engineering, nuclear science and engineering, brain and cognitive sciences, and materials science and engineering departments and its program in Health Sciences and Technology; and at the University Medical Center Hamburg-Eppendorf; Brown University; and the Massachusetts General Hospital. It was supported by the MIT-Harvard NIH Center for Cancer Nanotechnology, the Army Research Office through MIT’s Institute for Soldier Nanotechnologies, the NIH-funded Laser Biomedical Research Center, the MIT Deshpande Center, and the European Union Seventh Framework Program.
Here’s a link to and a citation for the paper,
Exceedingly small iron oxide nanoparticles as positive MRI contrast agents by He Wei, Oliver T. Bruns, Michael G. Kaul, Eric C. Hansen, Mariya Barch, Agata Wiśniowsk, Ou Chen, Yue Chen, Nan Li, Satoshi Okada, Jose M. Cordero, Markus Heine, Christian T. Farrar, Daniel M. Montana, Gerhard Adam, Harald Ittrich, Alan Jasanoff, Peter Nielsen, and Moungi G. Bawendi. PNAS February 13, 2017 doi: 10.1073/pnas.1620145114 Published online before print February 13, 2017
Researchers at Australia’s University of New South of Wales (UNSW) have devised a means of ‘weaving’ a material that mimics *bone tissue, periosteum according to a Jan. 11, 2017 news item on ScienceDaily,
For the first time, UNSW [University of New South Wales] biomedical engineers have woven a ‘smart’ fabric that mimics the sophisticated and complex properties of one nature’s ingenious materials, the bone tissue periosteum.
Having achieved proof of concept, the researchers are now ready to produce fabric prototypes for a range of advanced functional materials that could transform the medical, safety and transport sectors. Patents for the innovation are pending in Australia, the United States and Europe.
Potential future applications range from protective suits that stiffen under high impact for skiers, racing-car drivers and astronauts, through to ‘intelligent’ compression bandages for deep-vein thrombosis that respond to the wearer’s movement and safer steel-belt radial tyres.
Many animal and plant tissues exhibit ‘smart’ and adaptive properties. One such material is the periosteum, a soft tissue sleeve that envelops most bony surfaces in the body. The complex arrangement of collagen, elastin and other structural proteins gives periosteum amazing resilience and provides bones with added strength under high impact loads.
Until now, a lack of scalable ‘bottom-up’ approaches by researchers has stymied their ability to use smart tissues to create advanced functional materials.
UNSW’s Paul Trainor Chair of Biomedical Engineering, Professor Melissa Knothe Tate, said her team had for the first time mapped the complex tissue architectures of the periosteum, visualised them in 3D on a computer, scaled up the key components and produced prototypes using weaving loom technology.
“The result is a series of textile swatch prototypes that mimic periosteum’s smart stress-strain properties. We have also demonstrated the feasibility of using this technique to test other fibres to produce a whole range of new textiles,” Professor Knothe Tate said.
In order to understand the functional capacity of the periosteum, the team used an incredibly high fidelity imaging system to investigate and map its architecture.
“We then tested the feasibility of rendering periosteum’s natural tissue weaves using computer-aided design software,” Professor Knothe Tate said.
The computer modelling allowed the researchers to scale up nature’s architectural patterns to weave periosteum-inspired, multidimensional fabrics using a state-of-the-art computer-controlled jacquard loom. The loom is known as the original rudimentary computer, first unveiled in 1801.
“The challenge with using collagen and elastin is their fibres, that are too small to fit into the loom. So we used elastic material that mimics elastin and silk that mimics collagen,” Professor Knothe Tate said.
In a first test of the scaled-up tissue weaving concept, a series of textile swatch prototypes were woven, using specific combinations of collagen and elastin in a twill pattern designed to mirror periosteum’s weave. Mechanical testing of the swatches showed they exhibited similar properties found in periosteum’s natural collagen and elastin weave.
First author and biomedical engineering PhD candidate, Joanna Ng, said the technique had significant implications for the development of next-generation advanced materials and mechanically functional textiles.
While the materials produced by the jacquard loom have potential manufacturing applications – one tyremaker believes a titanium weave could spawn a new generation of thinner, stronger and safer steel-belt radials – the UNSW team is ultimately focused on the machine’s human potential.
“Our longer term goal is to weave biological tissues – essentially human body parts – in the lab to replace and repair our failing joints that reflect the biology, architecture and mechanical properties of the periosteum,” Ms Ng said.
An NHMRC development grant received in November  will allow the team to take its research to the next phase. The researchers will work with the Cleveland Clinic and the University of Sydney’s Professor Tony Weiss to develop and commercialise prototype bone implants for pre-clinical research, using the ‘smart’ technology, within three years.
In searching for more information about this work, I found a Winter 2015 article (PDF; pp. 8-11) by Amy Coopes and Steve Offner for UNSW Magazine about Knothe Tate and her work (Note: In Australia, winter would be what we in the Northern Hemisphere consider summer),
Tucked away in a small room in UNSW’s Graduate School of Biomedical Engineering sits a 19th century–era weaver’s wooden loom. Operated by punch cards and hooks, the machine was the first rudimentary computer when it was unveiled in 1801. While on the surface it looks like a standard Jacquard loom, it has been enhanced with motherboards integrated into each of the loom’s five hook modules and connected to a computer. This state-of-the-art technology means complex algorithms control each of the 5,000 feed-in fibres with incredible precision.
That capacity means the loom can weave with an extraordinary variety of substances, from glass and titanium to rayon and silk, a development that has attracted industry attention around the world.
The interest lies in the natural advantage woven materials have over other manufactured substances. Instead of manipulating material to create new shades or hues as in traditional weaving, the fabrics’ mechanical properties can be modulated, to be stiff at one end, for example, and more flexible at the other.
“Instead of a pattern of colours we get a pattern of mechanical properties,” says Melissa Knothe Tate, UNSW’s Paul Trainor Chair of Biomedical Engineering. “Think of a rope; it’s uniquely good in tension and in bending. Weaving is naturally strong in that way.”
The interface of mechanics and physiology is the focus of Knothe Tate’s work. In March , she travelled to the United States to present another aspect of her work at a meeting of the international Orthopedic Research Society in Las Vegas. That project – which has been dubbed “Google Maps for the body” – explores the interaction between cells and their environment in osteoporosis and other degenerative musculoskeletal conditions such as osteoarthritis.
Using previously top-secret semiconductor technology developed by optics giant Zeiss, and the same approach used by Google Maps to locate users with pinpoint accuracy, Knothe Tate and her team have created “zoomable” anatomical maps from the scale of a human joint down to a single cell.
She has also spearheaded a groundbreaking partnership that includes the Cleveland Clinic, and Brown and Stanford universities to help crunch terabytes of data gathered from human hip studies – all processed with the Google technology. Analysis that once took 25 years can now be done in a matter of weeks, bringing researchers ever closer to a set of laws that govern biological behaviour. [p. 9]
I gather she was recruited from the US to work at the University of New South Wales and this article was to highlight why they recruited her and to promote the university’s biomedical engineering department, which she chairs.
Getting back to 2017, here’s a link to and citation for the paper,
You wouldn’t think a sponge (the sea creature) was particularly tough but it is according to a Jan. 4, 2017 news item on Nanowerk,
Judging by their name alone, orange puffball sea sponges might seem unlikely paragons of structural strength. But maintaining their shape at the bottom of the churning ocean is critical to the creatures’ survival, and new research shows that tiny structural rods in their bodies have evolved the optimal shape to avoid buckling under pressure.
The rods, called strongyloxea spicules, measure about 2 millimeters long and are thinner than a human hair. Hundreds of them are bundled together, forming stiff rib-like structures inside the orange puffball’s spongy body. It was the odd and remarkably consistent shape of each spicule that caught the eye of Brown University engineers Haneesh Kesari and Michael Monn. Each one is symmetrically tapered along its length — going gradually from fatter in the middle to thinner at the ends.
Caption: Tiny rods found inside the bodies of orange puffball sea sponges have an interesting tapered shape. That shape, new research shows, turns out to be a match for the Clausen profile, a column shape shown to be optimal for resistance to buckling failure. Credit: Michael Monn, Haneesh Kesari / Brown University
Using structural mechanics models and a bit of digging in obscure mathematics journals, Monn and Kesari showed the peculiar shape of the spicules to be optimal for resistance to buckling, the primary mode of failure for slender structures. This natural shape could provide a blueprint for increasing the buckling resistance in all kinds of slender human-made structures, from building columns to bicycle spokes to arterial stents, the researchers say.
“This is one of the rare examples that we’re aware of where a natural structure is not just well-suited for a given function, but actually approaches a theoretical optimum,” said Kesari, an assistant professor of engineering at Brown. “There’s no engineering analog for this shape — we don’t see any columns or other slender structures that are tapered in this way. So in this case, nature has shown us something quite new that we think could be useful in engineering.”
The findings are published in the journal Scientific Reports.
Function and form
Orange puffball sponges (Tethya aurantia) are native to the Mediterranean Sea. They live mainly in rocky coastal environments, where they’re subject to the constant stress of underwater waves and tidal forces. Sponges are filter feeders — they pump water through their bodies to extract nutrients and oxygen. To do this, their bodies need to be porous and compliant, but they also need enough stiffness to avoid being deformed too much.
“If you compress them too much, you’re essentially choking them,” Kesari said. “So maintaining their stiffness is critical to their survival.”
And that means the spicules, which make up the rib-like structures that give sponges their stiffness, are critical components. When Monn and Kesari saw the shapes of the spicules under a microscope, the consistency of the tapered shape from spicule to spicule was hard to miss.
“We saw the shape and wondered if there might be an engineering principle at work here,” Kesari said.
To figure that out, the researchers first needed to understand what forces were acting on each individual spicule. So Monn and Kesari developed a structural mechanics model of spicules bundled within a sponge’s ribs. The model showed that the mismatch in stiffness between the bulk of the sponge’s soft body and the more rigid spicules causes each spicule to experience primarily one type of mechanical loading — a compression load on each of its ends.
“You can imagine taking a toothpick and trying to squeeze it longways between your fingers,” Monn said. “That’s how these spicules see the world.”
The primary mode of failure for a structure with this mechanical load is through buckling. At a certain critical load, the structure starts to bend somewhere along its length. Once the bending starts, the force transferred by the load is amplified at the bending point, which causes the structure to break or collapse.
Once Kesari and Monn knew what forces were acting on the spicules and how they would fail, the next step was looking to see if there was anything special about them that helped them resist buckling. Scanning electron microscope images of the inside of a spicule and other tests showed that they were monolithic silica — essentially glass.
“We could see that there was no funny business going on with the material properties,” Monn said. “If there was anything contributing to its mechanical performance, it would have to be the shape.”
Kesari and Monn combed the literature to see if they could find anything on tapering in slender structures. They came up empty in the modern engineering literature. But they found something interesting published more than 150 years ago by a German scientist named Thomas Clausen.
In 1851, Clausen proposed that columns that are tapered toward their ends should have more buckling resistance than plain cylinders, which had been and still are the primary design for architectural columns. In the 1960s, mathematician Joseph Keller published an ironclad mathematical proof that the Clausen column was indeed optimal for resistance to buckling — having 33 percent better resistance than a cylinder. Even compared to a very similar shape — an ellipse, which is slightly fatter in the middle and pointier at the ends — the Clausen column had 18 percent better buckling resistance.
Knowing what the optimal column shape is, Monn and Kesari started making precise dimensional measurements of dozens of spicules. They showed that their shapes were remarkably consistent and nearly identical to that of the Clausen column.
“The spicules were a match for the best shape of all possible column shapes,” Monn said.
It seems in this case, natural selection figured out something that engineers have not. Despite the fact that it’s been mathematically shown to be the optimal column shape, the Clausen profile isn’t widely known in the engineering community. Kesari and Monn hope this work might bring it out of the shadows.
“We see this as an addition to our library of structural designs,” Monn said. “We’re not just talking about an improvement of a few percent. This shape is 33 percent better than the cylinder, which is quite an improvement.”
In particular, the shape would be particularly useful in a new generation of materials made from nanoscale truss structures. “It would be easy to 3-D print the Clausen profile into these materials, and you’d get a tremendous increase in buckling resistance, which is often how these materials fail.”
Lessons from nature
The field of bio-inspired engineering began at a time when many people viewed adaptive evolution as an unceasing march toward perfection. If that were true, scientists should find untold numbers of optimal structures in nature.
But the modern understanding of evolution is a bit different. It’s now understood that in order for a trait to be conserved by natural selection, it doesn’t need to be optimal. It just needs to be good enough to work. That has put a bit of a damper on the enthusiasm for bio-inspired engineering, Kesari and Monn say.
However, they say, this work shows that nearly optimal structures are out there if researchers look in the right places. In this case, they looked at creatures from a very old phylum — sea sponges are among the very first animals on Earth — with plenty of time to evolve under consistent selection pressures.
Sponges are also fairly simple creatures, so understanding the function of a given trait is relatively straightforward. In this case, the spicule appears to have one and only one job to do — provide stiffness. Compare that to, for example, human bone, which not only provides support but must also accommodate arteries, provide attachment points for muscles and house bone marrow. Those other functions may cause tradeoffs in adaptations for strength or stiffness.
“With the sponges, you have lots of evolutionary pressure, lots of time and opportunity to respond to that pressure, and functional elements that can be easily identified,” Kesari said.
With those as guiding principles, there may well be more ideal structures out there waiting to be found.
“This work shows that nature can hit an optimum,” Kesari said, “and the biological world can still be hiding completely new designs of considerable technological significance in plain sight.”