Researchers at Tohoku University and the University of Gothenburg have established a new spintronic technology for brain-inspired computing.
Their achievement was published in the journal Nature Materials (“Memristive control of mutual SHNO synchronization for neuromorphic computing”).
Sophisticated cognitive tasks, such as image and speech recognition, have seen recent breakthroughs thanks to deep learning. Even so, the human brain still executes these tasks without exerting much energy and with greater efficiency than any computer. The development of energy-efficient artificial neurons capable of emulating brain-inspired processes has therefore been a major research goal for decades.
Researchers demonstrated the first integration of a cognitive computing nano-element – the memristor – into another – a spintronic oscillator. Arrays of these memristor-controlled oscillators combine the non-volatile local storage of the memristor function with the microwave frequency computation of the nano-oscillator networks and can closely imitate the non-linear oscillatory neural networks of the human brain.
Resistance of the memristor changed with the voltage hysteresis applied to the top Ti/Cu electrode. Upon voltage application to the electrode, an electric field was applied at the high-resistance state, compared to electric current flows for the low-resistance state. The effects of electric field and current on the oscillator differed from each other, offering various controls of oscillation and synchronization properties.
Professor Johan Åkerman of the University of Gothenburg and leader of the study expressed his hopes for the future and the significance of the finding. “We are particularly interested in emerging quantum-inspired computing schemes, such as Ising Machines. The results also highlight the productive collaboration that we have established in neuromorphic spintronics between the University of Gothenburg and Tohoku University, something that is also part of the Sweden-Japan collaborative network MIRAI 2.0.”
“So far, artificial neurons and synapses have been developed separately in many fields; this work marks an important milestone: two functional elements have been combined into one,” said professor Shunsuke Fukami, who led the project on the Tohoku University side. Dr. Mohammad Zahedinejad of the University of Gothenburg and first author of the study adds, “Using the memristor-controlled spintronic oscillator arrays, we could tune the synaptic interactions between adjacent neurons and program them into mutually different and partially synchronized states.”
To put into practice their discovery, the researchers examined the operation of a test device comprising one oscillator and one memristor. The constricted region of W/CoFeB stack served as an oscillator, i.e., the neuron, whereas the MgO/AlOx/SiNx stack acted as a memristor, i.e., the synapse.
Resistance of the memristor changed with the voltage hysteresis applied to the top Ti/Cu electrode. Upon voltage application to the electrode, an electric field was applied at the high-resistance state, compared to electric current flows for the low-resistance state. The effects of electric field and current on the oscillator differed from each other, offering various controls of oscillation and synchronization properties.
Professor Johan Åkerman of the University of Gothenburg and leader of the study expressed his hopes for the future and the significance of the finding. “We are particularly interested in emerging quantum-inspired computing schemes, such as Ising Machines. The results also highlight the productive collaboration that we have established in neuromorphic spintronics between the University of Gothenburg and Tohoku University, something that is also part of the Sweden-Japan collaborative network MIRAI 2.0.” [sic]
It is a staple of science fiction to mock sutures as outdated. The technique has, after all, been in use for at least 5,000 years. Surely medicine should have advanced since ancient Egypt. Professor Hossam Haick from the Wolfson Department of Chemical Engineering at the Technion has finally turned science fiction into reality. His lab succeeded in creating a smart sutureless dressing that binds the wound together, wards off infection, and reports on the wound’s condition directly to the doctors’ computers. Their study was published in Advanced Materials.
Current surgical procedures entail the surgeon cutting the human body, doing what needs to be done, and sewing the wound shut – an invasive procedure that damages surrounding healthy tissue. Some sutures degrade by themselves – or should degrade – as the wound heals. Others need to be manually removed. Dressing is then applied over the wound and medical personnel monitor the wound by removing the dressing to allow observation for signs of infection like swelling, redness, and heat. This procedure is painful to the patient, and disruptive to healing, but it is unavoidable. Working with these methods also mean that infection is often discovered late, since it takes time for visible signs to appear, and more time for the inspection to come round and see them. In developed countries, with good sanitation available, about 20% of patients develop infections post-surgery, necessitating additional treatment and extending the time to recovery. The figure and consequences are much worse in developing countries.
How will it work with Prof. Haick’s new dressing?
Prior to beginning a procedure, the dressing – which is very much like a smart band-aid – developed by Prof. Haick’s lab will be applied to the site of the planned incision. The incision will then be made through it. Following the surgery, the two ends of the wound will be brought together, and within three seconds the dressing will bind itself together, holding the wound closed, similarly to sutures. From then, the dressing will be continuously monitoring the wound, tracking the healing process, checking for signs of infection like changes in temperature, pH, and glucose levels, and report to the medical personnel’s smartphones or other devices. The dressing will also itself release antibiotics onto the wound area, preventing infection.
“I was watching a movie on futuristic robotics with my kids late one night,” said Prof. Haick, “and I thought, what if we could really make self-repairing sensors?”
Most people discard their late-night cinema-inspired ideas. Not Prof. Haick, who, the very next day after his Eureka moment, was researching and making plans. The first publication about a self-healing sensor came in 2015 (read more about it on the Technion website here). At that time, the sensor needed almost 24 hours to repair itself. By 2020, sensors were healing in under a minute (read about the study by Muhammad Khatib, a student in Prof. Haick’s lab here), but while it had multiple applications, it was not yet biocompatible, that is, not usable in contact with skin and blood. Creating a polymer that would be both biocompatible and self-healing was the next step, and one that was achieved by postdoctoral fellow Dr. Ning Tang.
The new polymer is structured like a molecular zipper, made from sulfur and nitrogen: the surgeon’s scalpel opens it; then pressed together, it closes and holds fast. Integrated carbon nanotubes provide electric conductivity and the integration of the sensor array. In experiments, wounds closed with the smart dressing healed as fast as those closed with sutures and showed reduced rates of infection.
“It’s a new approach to wound treatment,” said Prof. Haick. “We introduce the advances of the fourth industrial revolution – smart interconnected devices, into the day-to-day treatment of patients.”
Prof. Haick is the head of the Laboratory for Nanomaterial-based Devices (LNBD) and the Dean of Undergraduate Studies at the Technion. Dr. Ning Tang was a postdoctoral fellow in Prof. Haick’s laboratory and conducted this study as part of his fellowship. He has now been appointed an associate professor in Shanghai Jiao Tong University.
I usually like to have three links to a news/press release and in my searches for a third source for this press release, I stumbled onto the technioncanada.org website. They seemed to have scooped everyone including Technion as they have a November 25, 2021posting of the press release.
A team of University of Arizona researchers has developed an ultra-thin wireless device that grows to the surface of bone and could someday help physicians monitor bone health and healing over long periods. The devices, called osseosurface electronics, are described in a paper published Thursday [November 18, 2021] in Nature Communication
“As a surgeon, I am most excited about using measurements collected with osseosurface electronics to someday provide my patients with individualized orthopedic care – with the goal of accelerating rehabilitation and maximizing function after traumatic injuries,” said study co-senior author Dr. David Margolis, an assistant professor of orthopedic surgery in the UArizona College of Medicine – Tucson and orthopedic surgeon at Banner – University Medical Center Tucson.
Fragility fractures associated with conditions like osteoporosis account for more days spent in the hospital than heart attacks, breast cancer or prostate cancer. Although not yet tested or approved for use in humans, the wireless bone devices could one day be used not only to monitor health, but to improve it, said study co-senior author Philipp Gutruf, an assistant professor of biomedical engineering and Craig M. Berge faculty fellow in the College of Engineering.
“Being able to monitor the health of the musculoskeletal system is super important,” said Gutruf, who is also a member of the university’s BIO5 Institute. “With this interface, you basically have a computer on the bone. This technology platform allows us to create investigative tools for scientists to discover how the musculoskeletal system works and to use the information gathered to benefit recovery and therapy.”
Because muscles are so close to bones and move so frequently, it is important that the device be thin enough to avoid irritating surrounding tissue or becoming dislodged, Gutruf explained.
“The device’s thin structure, roughly as thick as a sheet of paper, means it can conform to the curvature of the bone, forming a tight interface,” said Alex Burton, a doctoral student in biomedical engineering and co-first author of the study. “They also do not need a battery. This is possible using a power casting and communication method called near-field communication, or NFC, which is also used in smartphones for contactless pay.”
Ceramic Adhesive Grows to Bone
The outer layers of bones shed and renew just like the outer layers of skin. So, if a traditional adhesive was used to attach something to the bone, it would fall off after just a few months. To address this challenge, study co-author and BIO5 Institute member John Szivek – a professor of orthopedic surgery and biomedical engineering – developed an adhesive that contains calcium particles with an atomic structure similar to bone cells, which is used as to secure osseosurface electronics to the bone.
“The bone basically thinks the device is part of it, and grows to the sensor itself,” Gutruf said. “This allows it to form a permanent bond to the bone and take measurements over long periods of time.”
For instance, a doctor could attach the device to a broken or fractured bone to monitor the healing process. This could be particularly helpful in patients with conditions such as osteoporosis, since they frequently suffer refractures. Knowing how quickly and how well the bone is healing could also inform clinical treatment decisions, such as when to remove temporary hardware like plates, rods or screws.
Some patients are prescribed drugs designed to speed up bone healing or improve bone density, but these prescriptions can have side effects. Close bone monitoring would allow physicians to make more informed decisions about drug dosage levels.
For a change this October 19, 2021 item on phys.org isn’t highlighting a single research paper so much as it provides a history of graphene and context for research being done at the Joint Quantum Institute (JQI) at the University of Maryland (US),
Carbon is not the shiniest element, nor the most reactive, nor the rarest. But it is one of the most versatile.
Carbon is the backbone of life on earth and the fossil fuels that have resulted from the demise of ancient life. Carbon is the essential ingredient for turning iron into steel, which underlies technologies from medieval swords to skyscrapers and submarines. And strong, lightweight carbon fibers are used in cars, planes and windmills. Even just carbon on its own is extraordinarily adaptable: It is the only ingredient in (among other things) diamonds, buckyballs and graphite (the stuff used to make pencil lead).
This last form, graphite, is at first glance the most mundane, but thin sheets of it host a wealth of uncommon physics. Research into individual atom-thick sheets of graphite—called graphene—took off after 2004 when scientists developed a reliable way to produce it (using everyday adhesive tape to repeatedly peel layers apart). In 2010 early experiments demonstrating the quantum richness of graphene earned two researchers the Nobel Prize in physics.
In recent years, graphene has kept on giving. Researchers have discovered that stacking layers of graphene two or three at a time (called, respectively, bilayer graphene or trilayer graphene) and twisting the layers relative to each other opens fertile new territory for scientists to explore. Research into these stacked sheets of graphene is like the Wild West, complete with the lure of striking gold and the uncertainty of uncharted territory.
Researchers at JQI and the Condensed Matter Theory Center (CMTC) at the University of Maryland, including JQI Fellows Sankar Das Sarma and Jay Sau and others, are busy creating the theoretical physics foundation that will be a map of this new landscape. And there is a lot to map; the phenomena in graphene range from the familiar like magnetism to more exotic things like strange metallicity, different versions of the quantum Hall effect, and the Pomeranchuk effect—each of which involve electrons coordinating to produce unique behaviors. One of the most promising veins for scientific treasure is the appearance of superconductivity (lossless electrical flow) in stacked graphene.
“Here is a system where almost every interesting quantum phase of matter that theorists ever could imagine shows up in a single system as the twist angle, carrier density, and temperature are tuned in a single sample in a single experiment,” says Das Sarma, who is also the Director of the CMTC. “Sounds like magic or science fantasy, except it is happening every day in at least ten laboratories in the world.”
The richness and diversity of the electrical behaviors in graphene stacks has inspired a stampede of research. The 2021 American Physical Society March Meeting included 13 sessions addressing the topics of graphene or twisted bilayers, and Das Sarma hosted a day long virtual conference in June for researchers to discuss twisted graphene and the related research inspired by the topic. The topic of stacked graphene is extensively represented in scientific journals, and the online arXiv preprint server has over 2,000 articles posted about “bilayer graphene”—nearly 1,000 since 2018.
Perhaps surprisingly, graphene’s wealth of quantum research opportunities is tied to its physical simplicity.
An October 18, 2021 JQI news release by Bailey Bedford, which originated the news item, explains why researchers have described a twist found in graphene as ‘magic’,
Researchers have discovered that at a special, small twist angle (about 1.1 degrees)—whimsically named the “magic angle”—the environment is just right to create strong interactions that radically change its properties. When that precise angle is reached, the electrons tend to cluster around certain areas of the graphene, and new electrical behaviors suddenly appear as if summoned with a dramatic magician’s flourish. Magic angle graphene behaves as a poorly-conducting insulator in some circumstances and in other cases goes to the opposite extreme of being a superconductor—a material that transports electricity without any loss of energy.
The discovery of magic-angle graphene and that it has certain quantum behaviors similar to a high-temperature superconductor was the Physics World 2018 Breakthrough of the Year. Superconductors have many valuable potential uses, like revolutionizing energy infrastructure and making efficient maglev trains. Finding a convenient, room-temperature superconductor has been a holy grail for scientists.
I haven’t done to justice to this piece and, so, for anyone interested in graphene, superconductors, and electronics I recommend reading the piece (October 18, 2021 JQI news release by Bailey Bedford) in its entirety where you’ll also find references to these articles and more,
The word ‘living’ isn’t usually associated with optical fibers and the addition had me thinking that this October 11, 2021 Nanowerk Spotlight story by Michael Berger would be a synthetic biology story. Well, not exactly. Do read on for a good introduction describing glass, fiber optics, and optogenetics,
Glass is one of the oldest manufactured materials used by humans and glass making dates back at least 6000 years, long before humans had discovered how to smelt iron. Glasses have been based on the chemical compound silica – silicon dioxide, or quartz – the primary constituent of sand. Soda-lime glass, containing around 70% silica, accounts for around 90% of manufactured glass.
Historically, we are familiar with glasses’ decorative use or as window panes, household items, and in optics such as eyeglasses, microscopes and telescopes. More recently, starting in the 1950s, glass has been used in the manufacture of fiber optic cables, a technology that has revolutionized the communications industry and helped ring in the digital revolution.
Fiber optic cables propagate a signal as a pulse of light along a transparent medium, usually glass. This is not only used to transmit information but, for instance in many healthcare and biomedical applications, scientists use optical fibers for sensing applications by shining light into a sample and evaluating the absorbed or transmitted light.
A recent development in this field is optogenetics, a neuromodulation method that uses activation or deactivation of brain cells by illumination with different colors of light in order to treat brain disorders.
Berger goes on to explain the latest work and reveals what ‘living’ means where this work is concerned,
This work represents a simple and low-cost approach to fabricating optical fibers made from biological materials. These fibers can be easily modified for specific applications and don’t require sophisticated equipment to generate relevant information. This method could be used for many practical sensing and biological modeling applications.
“We use a natural, ionic, and biologically compatible crosslinking approach, which enables us to produce flexible hydrogel fibers in continuous multi-layered architectures, meaning they are easy to produce and can be modified after fabrication,” explains Guimarães [Carlos Guimarães, the paper’s first author]. “Similarly to silica fibers, the core hydrogel of our structures can be exposed, fused to another fiber or reassembled if they break, and efficiently guide light through the established connection.”
These flexible hydrogel fibers are made from sugars and work just like solid-state optical fibers used to transmit data. However, they are biocompatible so they can be easily integrated with biological systems.
“We could even consider them to be alive [emphasis mine] since we can use them to grow living cells inside the fiber,” says Guimarães. “As these embedded cells grow over time, we can then use light to inform on living dynamic events, for example to track cancer invasive proliferation into optical information.” [emphasis mine]
As to what constitutes optical information in this context,
Another intriguing aspect of these hydrogel fibers is that their permeable mesh enables the inclusion of biological targets of interest for detection. For example, the scientists observed that fibers were able to soak SARS-CoV-2 viruses, and by integrating nanoparticles for their binding and detection, shifts in visible light could be observed for detecting the accumulation of viral particles within the fiber.
“When light moving through the fiber encounters living cells, it changes its characteristics depending on cellular density, invasive proliferation, expression of molecules, etc.” Guimarães notes. “This light-cell interaction can digitize complex biological events, converting responses such as cancer cell progression in 3D environments and susceptibility to drugs into numbers and data, very fast and without the need for sample destruction.”
I have not seen aluminum called aluminium in quite some time. (I’ve always had a fondness for that extra syllable.) I first saw notice of this work from Austria in an October 11, 2021 news item on Nanowerk,
A novel electronic component from TU Wien (Vienna) could be an important key to the era of quantum information technology: Using a special manufacturing process, pure germanium is bonded with aluminium in a way that atomically sharp interfaces are created. This results in a so-called monolithic metal-semiconductor-metal heterostructure.
This structure shows unique effects that are particularly evident at low temperatures. The aluminium becomes superconducting – but not only that, this property is also transferred to the adjacent germanium semiconductor and can be specifically controlled with electric fields. This makes it excellently suited for complex applications in quantum technology, such as processing quantum bits.
A particular advantage is that using this approach, it is not necessary to develop completely new technologies. Instead, mature and well established semiconductor fabrication techniqueses can be used to enable germanium-based quantum electronics.
Germanium: difficult to form high-quality contacts
“Germanium is a material which will definitely play an important role in semiconductor technology for the development of faster and more energy-efficient components,” says Dr. Masiar Sistani from the Institute for Solid State Electronics at TU Wien. However, if it is used to produce components on a nanometre scale, major problems arise: the material makes it extremely difficult to produce high-quality electrical contacts. This is related to the high impact of even smallest impurities at the contact points that significantly alter the electrical properties. “We have therefore set ourselves the task of developing a new manufacturing method that enables reliable and reproducible contact properties”, says Masiar Sistani.
The key is temperature: when nanometre-structured germanium and aluminium are brought into contact and heated, the atoms of both materials begin to diffuse into the neighbouring material – but to very different extents: the germanium atoms move rapidly into the aluminium, whereas aluminium hardly diffuses into the germanium at all. “Thus, if you connect two aluminium contacts to a thin germanium nanowire and raise the temperature to 350 degrees Celsius, the germanium atoms diffuse off the edge of the nanowire. This creates empty spaces into which the aluminium can then easily penetrate,” explains Masiar Sistani. “In the end, only a few nanometre area in the middle of the nanowire consists of germanium, the rest has been filled up by aluminium.”
Normally, aluminium is made up of tiny crystal grains, but this novel fabrication method forms a perfect single crystal in which the aluminium atoms are arranged in a uniform pattern. As can be seen under the transmission electron microscope, a perfectly clean and atomically sharp transition is formed between germanium and aluminium, with no disordered region in between. In contrast to conventional methods where electrical contacts are applied to a semiconductor, for example by evaporating a metal, no oxides can form at the boundary layer.
Quantum transport in Grenoble
In order to take a closer look at the properties of this monolithic metal-semiconductor heterostructure of germanium and aluminium at low temperature, we collaborated with Dr. Olivier Buisson and Dr. Cécile Naud from the quantum electronics circuits group at Néel Institute – CNRS-UGA [Centre National de la Recherche Scientifique; Université Grenoble Alpes] in Grenoble. It turned out that the novel structure indeed has quite remarkable properties: “Not only were we able to demonstrate superconductivity in pure, undoped germanium for the first time, we were also able to show that this structure can be switched between quite different operating states using electric fields. Such a germanium quantum dot device can not only be superconducting but also completely insulating, or it can behave like a Josephson transistor, an important basic element of quantum electronic circuits,” explains Masiar Sistani.
This new heterostructure combines a whole range of advantages: The structure has excellent physical properties needed for quantum technologies, such as high carrier mobility and excellent manipulability with electric fields, and it has the additional advantage of fitting well with already established microelectronics technologies: Germanium is already used in current chip architectures and the temperatures required for heterostructure formation are compatible with well-established semiconductor processing schemes. The novel structures not only have theoretically interesting quantum properties, but also opens up a technologically very realistic possibility of enabling further novel and energy-saving devices.
Here’s a link to and a citation for the paper,
Al–Ge–Al Nanowire Heterostructure: From Single-Hole Quantum Dot to Josephson Effect by Jovian Delaforce, Masiar Sistani, Roman B. G. Kramer, Minh A. Luong, Nicolas Roch, Walter M. Weber, Martien I. den Hertog, Eric Robin, Cecile Naud, Alois Lugstein, Olivier Buisson. Advanced Materials Volume 33, Issue 39 October 1, 2021 2101989 DOI: https://doi.org/10.1002/adma.202101989 First published [online]: 08 August 2021
This story got me to thinking about what happens when any kind of implant company (pacemaker, deep brain stimulator, etc.) goes bankrupt or is acquired by another company with a different business model.
As I worked on this piece, more issues were raised and the scope expanded to include prosthetics along with implants while the focus narrowed to neuro as in, neural implants and neuroprosthetics. At the same time, I found salient examples for this posting in other medical advances such as gene editing.
In sum, all references to implants and prosthetics are to neural devices and some issues are illustrated with salient examples from other medical advances (specifically, gene editing).
Medical implants are devices or tissues that are placed inside or on the surface of the body. Many implants are prosthetics, intended to replace missing body parts. Other implants deliver medication, monitor body functions, or provide support to organs and tissues.
As for what constitutes a neural implant/neuroprosthetic, there’s this from Emily Waltz’s January 20, 2020 article (How Do Neural Implants Work? Neural implants are used for deep brain stimulation, vagus nerve stimulation, and mind-controlled prostheses) for the Institute of Electrical and Electronics Engineers (IEEE) Spectrum magazine,
A neural implant, then, is a device—typically an electrode of some kind—that’s inserted into the body, comes into contact with tissues that contain neurons, and interacts with those neurons in some way.
Now, let’s start with the recent near bankruptcy of a retinal implant company.
Barbara Campbell was walking through a New York City subway station during rush hour when her world abruptly went dark. For four years, Campbell had been using a high-tech implant in her left eye that gave her a crude kind of bionic vision, partially compensating for the genetic disease that had rendered her completely blind in her 30s. “I remember exactly where I was: I was switching from the 6 train to the F train,” Campbell tells IEEE Spectrum. “I was about to go down the stairs, and all of a sudden I heard a little ‘beep, beep, beep’ sound.’”
It wasn’t her phone battery running out. It was her Argus II retinal implant system powering down. The patches of light and dark that she’d been able to see with the implant’s help vanished.
Terry Byland is the only person to have received this kind of implant in both eyes. He got the first-generation Argus I implant, made by the company Second Sight Medical Products, in his right eye in 2004, and the subsequent Argus II implant in his left 11 years later. He helped the company test the technology, spoke to the press movingly about his experiences, and even met Stevie Wonder at a conference. “[I] went from being just a person that was doing the testing to being a spokesman,” he remembers.
Yet in 2020, Byland had to find out secondhand that the company had abandoned the technology and was on the verge of going bankrupt. While his two-implant system is still working, he doesn’t know how long that will be the case. “As long as nothing goes wrong, I’m fine,” he says. “But if something does go wrong with it, well, I’m screwed. Because there’s no way of getting it fixed.”
Ross Doerr, another Second Sight patient, doesn’t mince words: “It is fantastic technology and a lousy company,” he says. He received an implant in one eye in 2019 and remembers seeing the shining lights of Christmas trees that holiday season. He was thrilled to learn in early 2020 that he was eligible for software upgrades that could further improve his vision. Yet in the early months of the COVID-19 pandemic, he heard troubling rumors about the company and called his Second Sight vision-rehab therapist. “She said, ‘Well, funny you should call. We all just got laid off,’ ” he remembers. “She said, ‘By the way, you’re not getting your upgrades.’ ”
These three patients, and more than 350 other blind people around the world with Second Sight’s implants in their eyes, find themselves in a world in which the technology that transformed their lives is just another obsolete gadget. One technical hiccup, one broken wire, and they lose their artificial vision, possibly forever. To add injury to insult: A defunct Argus system in the eye could cause medical complications or interfere with procedures such as MRI scans, and it could be painful or expensive to remove.
After Second Sight discontinued its retinal implant in 2019 and nearly went out of business in 2020, a public offering in June 2021 raised US $57.5 million at $5 per share. The company promised to focus on its ongoing clinical trial of a brain implant, called Orion, that also provides artificial vision. But its stock price plunged to around $1.50, and in February 2022, just before this article was published, the company announced a proposed merger with an early-stage biopharmaceutical company called Nano Precision Medical (NPM). None of Second Sight’s executives will be on the leadership team of the new company, which will focus on developing NPM’s novel implant for drug delivery.The company’s current leadership declined to be interviewed for this article but did provide an emailed statement prior to the merger announcement. It said, in part: “We are a recognized global leader in neuromodulation devices for blindness and are committed to developing new technologies to treat the broadest population of sight-impaired individuals.”
It’s unclear what Second Sight’s proposed merger means for Argus patients. The day after the merger was announced, Adam Mendelsohn, CEO of Nano Precision Medical, told Spectrum that he doesn’t yet know what contractual obligations the combined company will have to Argus and Orion patients. But, he says, NPM will try to do what’s “right from an ethical perspective.” The past, he added in an email, is “simply not relevant to the new future.”
Second Sight may have given up on its retinal implant, but other companies still see a need—and a market—for bionic vision without brain surgery. Paris-based Pixium Vision is conducting European and U.S. feasibility trials to see if its Prima system can help patients with age-related macular degeneration, a much more common condition than retinitis pigmentosa.
Daniel Palanker, a professor of ophthalmology at Stanford University who licensed his technology to Pixium, says the Prima implant is smaller, simpler, and cheaper than the Argus II. But he argues that Prima’s superior image resolution has the potential to make Pixium Vision a success. “If you provide excellent vision, there will be lots of patients,” he tells Spectrum. “If you provide crappy vision, there will be very few.”
Some clinicians involved in the Argus II work are trying to salvage what they can from the technology. Gislin Dagnelie, an associate professor of ophthalmology at Johns Hopkins University School of Medicine, has set up a network of clinicians who are still working with Argus II patients. The researchers are experimenting with a thermal camera to help users see faces, a stereo camera to filter out the background, and AI-powered object recognition. These upgrades are unlikely to result in commercial hardware today but could help future vision prostheses.
Failure is an inevitable part of innovation. The Argus II was an innovative technology, and progress made by Second Sight may pave the way for other companies that are developing bionic vision systems. But for people considering such an implant in the future, the cautionary tale of Argus patients left in the lurch may make a tough decision even tougher. Should they take a chance on a novel technology? If they do get an implant and find that it helps them navigate the world, should they allow themselves to depend upon it?
Abandoning the Argus II technology—and the people who use it—might have made short-term financial sense for Second Sight, but it’s a decision that could come back to bite the merged company if it does decide to commercialize a brain implant, believes Doerr.
For anyone curious about retinal implant technology (specifically the Argus II), I have a description in a June 30, 2015 posting.
Speculations and hopes for neuroprosthetics
The field of neuroprosthetics is very active. Dr Arthur Saniotis and Prof Maciej Henneberg have written an article where they speculate about the possibilities of a neuroprosthetic that may one day merge with neurons in a February 21, 2022 Nanowerk Spotlight article,
For over a generation several types of medical neuroprosthetics have been developed, which have improved the lives of thousands of individuals. For instance, cochlear implants have restored functional hearing in individuals with severe hearing impairment.
Further advances in motor neuroprosthetics are attempting to restore motor functions in tetraplegic, limb loss and brain stem stroke paralysis subjects.
Currently, scientists are working on various kinds of brain/machine interfaces [BMI] in order to restore movement and partial sensory function. One such device is the ‘Ipsihand’ that enables movement of a paralyzed hand. The device works by detecting the recipient’s intention in the form of electrical signals, thereby triggering hand movement.
Another recent development is the 12 month BMI gait neurohabilitation program that uses a visual-tactile feedback system in combination with a physical exoskeleton and EEG operated AI actuators while walking. This program has been tried on eight patients with reported improvements in lower limb movement and somatic sensation.
Surgically placed electrode implants have also reduced tremor symptoms in individuals with Parkinson’s disease.
Although neuroprosthetics have provided various benefits they do have their problems. Firstly, electrode implants to the brain are prone to degradation, necessitating new implants after a few years. Secondly, as in any kind of surgery, implanted electrodes can cause post-operative infection and glial scarring. Furthermore, one study showed that the neurobiological efficacy of an implant is dependent on the rate of speed of its insertion.
But what if humans designed a neuroprosthetic, which could bypass the medical glitches of invasive neuroprosthetics? However, instead of connecting devices to neural networks, this neuroprosthetic would directly merge with neurons – a novel step. Such a neuroprosthetic could radically optimize treatments for neurodegenerative disorders and brain injuries, and possibly cognitive enhancement [emphasis mine].
An interesting feature of their nanobot neuroprosthetic is that it has been inspired from nature by way of endomyccorhizae – a type of plant/fungus symbiosis, which is over four hundred million years old. During endomyccorhizae, fungi use numerous threadlike projections called mycelium that penetrate plant roots, forming colossal underground networks with nearby root systems. During this process fungi take up vital nutrients while protecting plant roots from infections – a win-win relationship. Consequently, the nano-neuroprosthetic has been named ‘endomyccorhizae ligand interface’, or ‘ELI’ for short.
The Spotlight article goes on to describe how these nanobots might function. As for the possibility of cognitive enhancement, I wonder if that might come to be described as a form of ‘artificial intelligence’.
(Dr Arthur Saniotis and Prof Maciej Henneberg are both from the Department of Anthropology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences; and Biological Anthropology and Comparative Anatomy Research Unit, Adelaide Medical School, University of Adelaide. Abdul-Rahman Sawalma who’s listed as an author on the 2018 paper is from the Palestinian Neuroscience Initiative, Al-Quds University, Beit Hanina, Palestine.)
Saniotis and Henneberg’s Spotlight article presents an optimistic view of neuroprosthetics. It seems telling that they cite cochlear implants as a success story when it is viewed by many as ethically fraught (see the Cochlear implant Wikipedia entry; scroll down to ‘Criticism and controversy’).
Technologist: What are the potential consequences of accepting the “augmented human” in society?
Gregor Wolbring: There are many that we might not even envision now. But let me focus on failure and obsolescence [emphasis mine], two issues that are rarely discussed. What happens when the mechanisms fails in the middle of an action? Failure has hazardous consequences, but obsolescence has psychological ones. …. The constant surgical intervention needed to update the hardware may not be feasible. A person might feel obsolete if she cohabits with others using a newer version.
T. Are researchers working on prosthetics sometimes disconnected from reality?
G. W. Students engaged in the development of prosthetics have to learn how to think in societal terms and develop a broader perspective. Our education system provides them with a fascination for clever solutions to technological challenges but not with tools aiming at understanding the consequences, such as whether their product might increase or decrease social justice.
Wolbring is a professor at the University of Calgary’s Cumming School of Medicine (profile page) who writes on social issues to do with human enhancement/ augmentation. As well,
Some of his areas of engagement are: ability studies including governance of ability expectations, disability studies, governance of emerging and existing sciences and technologies (e.g. nanoscale science and technology, molecular manufacturing, aging, longevity and immortality, cognitive sciences, neuromorphic engineering, genetics, synthetic biology, robotics, artificial intelligence, automatization, brain machine interfaces, sensors), impact of science and technology on marginalized populations, especially people with disabilities he governance of bodily enhancement, sustainability issues, EcoHealth, resilience, ethics issues, health policy issues, human rights and sport.
I’d classify Second Sight as a tech startup company and they have a high rate of failure, which may not have been clear to the patients who had the implants. Clinical trials can present problems too as this excerpt from my September 17, 2020 posting notes,
“In 2003, neurologist Helen Mayberg of Emory University in Atlanta began to test a bold, experimental treatment for people with severe depression, which involved implanting metal electrodes deep in the brain in a region called area 25 [emphases mine]. The initial data were promising; eventually, they convinced a device company, St. Jude Medical in Saint Paul, to sponsor a 200-person clinical trial dubbed BROADEN.
This month [October 2017], however, Lancet Psychiatry reported the first published data on the trial’s failure. The study stopped recruiting participants in 2012, after a 6-month study in 90 people failed to show statistically significant improvements between those receiving active stimulation and a control group, in which the device was implanted but switched off.
… a tricky dilemma for companies and research teams involved in deep brain stimulation (DBS) research: If trial participants want to keep their implants [emphases mine], who will take responsibility—and pay—for their ongoing care? And participants in last week’s meeting said it underscores the need for the growing corps of DBS researchers to think long-term about their planned studies.”
“It becomes part of you,” Patient 6 said, describing the technology that enabled her, after 45 years of severe epilepsy, to halt her disabling seizures. Electrodes had been implanted on the surface of her brain that would send a signal to a hand-held device when they detected signs of impending epileptic activity. On hearing a warning from the device, Patient 6 knew to take a dose of medication to halt the coming seizure.
“You grow gradually into it and get used to it, so it then becomes a part of every day,” she told Frederic Gilbert, an ethicist who studies brain–computer interfaces (BCIs) at the University of Tasmania in Hobart, Australia. “It became me,” she said. [emphasis mine]
Symbiosis is a term, borrowed from ecology, that means an intimate co-existence of two species for mutual advantage. As technologists work towards directly connecting the human brain to computers, it is increasingly being used to describe humans’ potential relationship with artificial intelligence. [emphasis mine]
For a lot of people these devices are or could be life-changing. At the same time, there are a number of different issues related to implants/prosthetics; the following is not an exhaustive list. As Wolbring notes, issues that we can’t begin to imagine now are likely to emerge as these medical advances become more ubiquitous.
Assistive technologies are almost always portrayed as helpful. For example, a cochlear implant gives people without hearing the ability to hear. The assumption is that this is always a good thing—unless you’re a deaf person who wants to define the problem a little differently. Who gets to decide what is good and ‘normal’ and what is desirable?
While the cochlear implant is the most extreme example I can think of, there are variations of these questions throughout the ‘disability’ communities.
Also, as Wolbring notes in his interview with the Technologist.eu, the education system tends to favour technological solutions which don’t take social issues into account. Wolbring cites social justice issues when he mentions failure and obsolescence.
Technical failures and obsolescence
The story, excerpted earlier in this posting, opened with a striking example of a technical failure at an awkward moment; a blind woman depending on her retinal implant loses all sight as she maneuvers through a subway station in New York City.
Aside from being an awful way to find out the company supplying and supporting your implant is in serious financial trouble and can’t offer assistance or repair, the failure offers a preview of what could happen as implants and prosthetics become more commonly used.
Keeping up/fomo (fear of missing out)/obsolescence
It used to be called ‘keeping up with the Joneses, it’s the practice of comparing yourself and your worldly goods to someone else(‘s) and then trying to equal what they have or do better. Usually, people want to have more and better than the mythical Joneses.
These days, the phenomenon (which has been expanded to include social networking) is better known as ‘fomo’ or fear of missing out (see the Fear of missing out Wikipedia entry).
Whatever you want to call it, humanity’s competitive nature can be seen where technology is concerned. When I worked in technology companies, I noticed that hardware and software were sometimes purchased for features that were effectively useless to us. But, not upgrading to a newer version was unthinkable.
Call it fomo or ‘keeping up with the Joneses’, it’s a powerful force and when people (and even companies) miss out or can’t keep up, it can lead to a sense of inferiority in the same way that having an obsolete implant or prosthetic could.
Could there be a neural implant/neuroprosthetic divide? There is already a digital divide (from its Wikipedia entry),
The digital divide is a gap between those who have access to new technology and those who do not … people without access to the Internet and other ICTs [information and communication technologies] are at a socio-economic disadvantage because they are unable or less able to find and apply for jobs, shop and sell online, participate democratically, or research and learn.
After reading Wolbring’s comments, it’s not hard to imagine a neural implant/neuroprosthetic divide with its attendant psychological and social consequences.
What kind of human am I?
There are other issues as noted in my September 17, 2020 posting. I’ve already mentioned ‘patient 6’, the woman who developed a symbiotic relationship with her brain/computer interface. This is how the relationship ended,
… He [Frederic Gilbert, ethicist] is now preparing a follow-up report on Patient 6. The company that implanted the device in her brain to help free her from seizures went bankrupt. The device had to be removed.
… Patient 6 cried as she told Gilbert about losing the device. … “I lost myself,” she said.
“It was more than a device,” Gilbert says. “The company owned the existence of this new person.”
More recently, Hugh Herr, an Associate Professor at the Massachusetts Institute of Technology (MIT), leader of the Biomechatronics research group at MIT’s Media Lab, a double amputee, and prosthetic enthusiast, starred in the recent (February 23, 2022) broadcast of ‘Augmented‘ on the Public Broadcasting Service (PBS) science programme, Nova.
I found ‘Augmented’ a little offputting as it gave every indication of being an advertisement for Herr’s work in the form of a hero’s journey. I was not able to watch more than 10 mins. This preview gives you a pretty good idea of what it was like although the part in ‘Augmented, where he says he’d like to be a cyborg hasn’t been included,
At a guess, there were a few talking heads (taking up from 10%-20% of the running time) who provided some cautionary words to counterbalance the enthusiasm in the rest of the programme. It’s a standard approach designed to give the impression that both sides of a question are being recognized. The cautionary material is usually inserted past the 1/2 way mark while leaving several minutes at the end for returning to the more optimistic material.
Written by Paul Hochman for Fast Company, Bionic Legs, iLimbs, and Other Super-Human Prostheses [ETA March 23, 2022: an updated version of the article is now on Genius.com] delves further into the world where people may be willing to trade a healthy limb for a prosthetic. From the article,
There are many advantages to having your leg amputated.
Pedicure costs drop 50% overnight. A pair of socks lasts twice as long. But Hugh Herr, the director of the Biomechatronics Group at the MIT Media Lab, goes a step further. “It’s actually unfair,” Herr says about amputees’ advantages over the able-bodied. “As tech advancements in prosthetics come along, amputees can exploit those improvements. They can get upgrades. A person with a natural body can’t.”
Herr is not the only one who favours prosthetics (also from the Hochman article),
This influx of R&D cash, combined with breakthroughs in materials science and processor speed, has had a striking visual and social result: an emblem of hurt and loss has become a paradigm of the sleek, modern, and powerful. Which is why Michael Bailey, a 24-year-old student in Duluth, Georgia, is looking forward to the day when he can amputate the last two fingers on his left hand.
“I don’t think I would have said this if it had never happened,” says Bailey, referring to the accident that tore off his pinkie, ring, and middle fingers. “But I told Touch Bionics I’d cut the rest of my hand off if I could make all five of my fingers robotic.”
But Bailey is most surprised by his own reaction. “When I’m wearing it, I do feel different: I feel stronger. As weird as that sounds, having a piece of machinery incorporated into your body, as a part of you, well, it makes you feel above human.[emphasis mine] It’s a very powerful thing.”
My September 17, 2020 posting touches on more ethical and social issues including some of those surrounding consumer neurotechnologies or brain-computer interfaces (BCI). Unfortunately, I don’t have space for these issues here.
In the IEEE Spectrum article, a tech start-up company, Second Sight, ran into financial trouble and is acquired by a company that has no plans to develop Second Sight’s core technology. The people implanted with the Argus II technology have been stranded as were ‘patient 6’ and others participating in the clinical trial described in the July 24, 2019 article by Liam Drew for Nature Outlook: The brain mentioned earlier in this posting.
I don’t know anything about the business bankruptcy mentioned in the Drew article but one of the business problems described in the IEEE Spectrum article suggests that Second Sight was founded before answering a basic question, “What is the market size for this product?”
On 18 July 2019, Second Sight sent Argus patients a letter saying it would be phasing out the retinal implant technology to clear the way for the development of its next-generation brain implant for blindness, Orion, which had begun a clinical trial with six patients the previous year. …
“The leadership at the time didn’t believe they could make [the Argus retinal implant] part of the business profitable,” Greenberg [Robert Greenberg, Second Sight co-founder] says. “I understood the decision, because I think the size of the market turned out to be smaller than we had thought.”
The question of whether a medical procedure or medicine can be profitable (or should the question be sufficiently profitable?) was referenced in my April 26, 2019 posting in the context of gene editing and personalized medicine
Edward Abrahams, president of the Personalized Medicine Coalition (US-based), advocates for personalized medicine while noting in passing, market forces as represented by Goldman Sachs in his May 23, 2018 piece for statnews.com (Note: A link has been removed),
Goldman Sachs, for example, issued a report titled “The Genome Revolution.” It argues that while “genome medicine” offers “tremendous value for patients and society,” curing patients may not be “a sustainable business model.” [emphasis mine] The analysis underlines that the health system is not set up to reap the benefits of new scientific discoveries and technologies. Just as we are on the precipice of an era in which gene therapies, gene-editing, and immunotherapies promise to address the root causes of disease, Goldman Sachs says that these therapies have a “very different outlook with regard to recurring revenue versus chronic therapies.”
The ‘Glybera’ story in my July 4, 2019 posting (scroll down about 40% of the way) highlights the issue with “recurring revenue versus chronic therapies,”
It cost $1M for a single treatment and that single treatment is good for at least 10 years.
Pharmaceutical companies make their money from repeated use of their medicaments and Glybera required only one treatment so the company priced it according to how much they would have gotten for repeated use, $100,000 per year over a 10 year period. The company was not able to persuade governments and/or individuals to pay the cost
In the end, 31 people got the treatment, most of them received it for free through clinical trials.
For rich people only?
Megan Devlin’s March 8, 2022 article for the Daily Hive announces a major research investment into medical research (Note: A link has been removed),
Vancouver [Canada] billionaire Chip Wilson revealed Tuesday [March 8, 2022] that he has a rare genetic condition that causes his muscles to waste away, and announced he’s spending $100 million on research to find a cure.
His condition is called facio-scapulo-humeral muscular dystrophy, or FSHD for short. It progresses rapidly in some people and more slowly in others, but is characterized by progressive muscle weakness starting the the face, the neck, shoulders, and later the lower body.
“I’m out for survival of my own life,” Wilson said.
“I also have the resources to do something about this which affects so many people in the world.”
Wilson hopes the $100 million will produce a cure or muscle-regenerating treatment by 2027.
“This could be one of the biggest discoveries of all time, for humankind,” Wilson said. “Most people lose muscle, they fall, and they die. If we can keep muscle as we age this can be a longevity drug like we’ve never seen before.”
According to rarediseases.org, FSHD affects between four and 10 people out of every 100,000 [emphasis mine], Right now, therapies are limited to exercise and pain management. There is no way to stall or reverse the disease’s course.
Wilson is best known for founding athleisure clothing company Lululemon. He also owns the most expensive home in British Columbia, a $73 million mansion in Vancouver’s Kitsilano neighbourhood.
Let’s see what the numbers add up to,
4 – 10 people out of 100,000
40 – 100 people out of 1M
1200 – 3,000 people out of 30M (let’s say this is Canada’s population)\
12,000 – 30,000 people out of 300M (let’s say this is the US’s population)
42,000 – 105,000 out of 1.115B (let’s say this is China’s population)
The rough total comes to 55,200 to 138,000 people between three countries with a combined population total of 1.445B. Given how business currently operates, it seems unlikely that any company will want to offer Wilson’s hoped for medical therapy although he and possibly others may benefit from a clinical trial.
Should profit or wealth be considerations?
The stories about the patients with the implants and the patients who need Glybera are heartbreaking and point to a question not often asked when medical therapies and medications are developed. Is the profit model the best choice and, if so, how much profit?
I have no answer to that question but I wish it was asked by medical researchers and policy makers.
As for wealthy people dictating the direction for medical research, I don’t have answers there either. I hope the research will yield applications and/or valuable information for more than Wilson’s disease.
It’s his money after all
Wilson calls his new venture, SolveFSHD. It doesn’t seem to be affiliated with any university or biomedical science organization and it’s not clear how the money will be awarded (no programmes, no application procedure, no panel of experts). There are three people on the team, Eva R. Chin, scientist and executive director, Chip Wilson, SolveFSHD founder/funder, and FSHD patient, and Neil Camarta, engineer, executive (fossil fuels and clean energy), and FSHD patient. There’s also a Twitter feed (presumably for the latest updates): https://twitter.com/SOLVEFSHD.
Low Tide Properties, the real estate arm of Lululemon founder Chip Wilson [emphasis mine], has submitted a new development permit application to build a 148-ft-tall, eight-storey, mixed-use commercial building in the False Creek Flats of Vancouver.
The proposal, designed by local architectural firm Musson Cattell Mackey Partnership, calls for 236,000 sq ft of total floor area, including 105,000 sq ft of general office space, 102,000 sq ft of laboratory space [emphasis mine], and 5,000 sq ft of ground-level retail space. An outdoor amenity space for building workers will be provided on the rooftop.
[next door] The 2001-built, five-storey building at 1618 Station Street immediately to the west of the development site is also owned by Low Tide Properties [emphasis mine]. The Ferguson, the name of the existing building, contains about 79,000 sq ft of total floor area, including 47,000 sq ft of laboratory space and 32,000 sq ft of general office space. Biotechnology company Stemcell technologies [STEMCELL] Technologies] is the anchor tenant [emphasis mine].
I wonder if this proposed new building will house SolveFSHD and perhaps other FSHD-focused enterprises. The proximity of STEMCELL Technologies could be quite convenient. In any event, $100M will buy a lot (pun intended).
Issues I’ve described here in the context of neural implants/neuroprosthetics and cutting edge medical advances are standard problems not specific to these technologies/treatments:
What happens when the technology fails (hopefully not at a critical moment)?
What happens when your supplier goes out of business or discontinues the products you purchase from them?
How much does it cost?
Who can afford the treatment/product? Will it only be for rich people?
Will this technology/procedure/etc. exacerbate or create new social tensions between social classes, cultural groups, religious groups, races, etc.?
Of course, having your neural implant fail suddenly in the middle of a New York City subway station seems a substantively different experience than having your car break down on the road.
There are, of course, there are the issues we can’t yet envision (as Wolbring notes) and there are issues such as symbiotic relationships with our implants and/or feeling that you are “above human.” Whether symbiosis and ‘implant/prosthetic superiority’ will affect more than a small number of people or become major issues is still to be determined.
There’s a lot to be optimistic about where new medical research and advances are concerned but I would like to see more thoughtful coverage in the media (e.g., news programmes and documentaries like ‘Augmented’) and more thoughtful comments from medical researchers.
Of course, the biggest issue I’ve raised here is about the current business models for health care products where profit is valued over people’s health and well-being. it’s a big question and I don’t see any definitive answers but the question put me in mind of this quote (from a September 22, 2020 obituary for US Supreme Court Justice Ruth Bader Ginsburg by Irene Monroe for Curve),
Ginsburg’s advocacy for justice was unwavering and showed it, especially with each oral dissent. In another oral dissent, Ginsburg quoted a familiar Martin Luther King Jr. line, adding her coda:” ‘The arc of the universe is long, but it bends toward justice,’” but only “if there is a steadfast commitment to see the task through to completion.” …
Martin Luther King Jr. popularized and paraphrased the quote (from a January 18, 2018 article by Mychal Denzel Smith for Huffington Post),
His use of the quote is best understood by considering his source material. “The arc of the moral universe is long, but it bends toward justice” is King’s clever paraphrasing of a portion of a sermon delivered in 1853 by the abolitionist minister Theodore Parker. Born in Lexington, Massachusetts, in 1810, Parker studied at Harvard Divinity School and eventually became an influential transcendentalist and minister in the Unitarian church. In that sermon, Parker said: “I do not pretend to understand the moral universe. The arc is a long one. My eye reaches but little ways. I cannot calculate the curve and complete the figure by experience of sight. I can divine it by conscience. And from what I see I am sure it bends toward justice.”
I choose to keep faith that people will get the healthcare products they need and that all of us need to keep working at making access more fair.
A team of physicists at CU Boulder [University of Colorado at Boulder] has solved the mystery behind a perplexing phenomenon in the nano realm: why some ultra-small heat sources cool down faster if you pack them closer together. The findings, published today in the journal Proceedings of the National Academy of Sciences (PNAS), could one day help the tech industry design faster electronic devices that overheat less.
“Often, heat is a challenging consideration in designing electronics. You build a device then discover that it’s heating up faster than desired,” said study co-author Joshua Knobloch, postdoctoral research associate at JILA, a joint research institute between CU Boulder and the National Institute of Standards and Technology (NIST). “Our goal is to understand the fundamental physics involved so we can engineer future devices to efficiently manage the flow of heat.”
The research began with an unexplained observation: In 2015, researchers led by physicists Margaret Murnane and Henry Kapteyn at JILA were experimenting with bars of metal that were many times thinner than the width of a human hair on a silicon base. When they heated those bars up with a laser, something strange occurred.
“They behaved very counterintuitively,” Knobloch said. “These nano-scale heat sources do not usually dissipate heat efficiently. But if you pack them close together, they cool down much more quickly.”
Now, the researchers know why it happens.
In the new study, they used computer-based simulations to track the passage of heat from their nano-sized bars. They discovered that when they placed the heat sources close together, the vibrations of energy they produced began to bounce off each other, scattering heat away and cooling the bars down.
The group’s results highlight a major challenge in designing the next generation of tiny devices, such as microprocessors or quantum computer chips: When you shrink down to very small scales, heat does not always behave the way you think it should.
Atom by atom
The transmission of heat in devices matters, the researchers added. Even minute defects in the design of electronics like computer chips can allow temperature to build up, adding wear and tear to a device. As tech companies strive to produce smaller and smaller electronics, they’ll need to pay more attention than ever before to phonons—vibrations of atoms that carry heat in solids.
“Heat flow involves very complex processes, making it hard to control,” Knobloch said. “But if we can understand how phonons behave on the small scale, then we can tailor their transport, allowing us to build more efficient devices.”
To do just that, Murnane and Kapteyn and their team of experimental physicists joined forces with a group of theorists led by Mahmoud Hussein, professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. His group specializes in simulating, or modeling, the motion of phonons.
“At the atomic scale, the very nature of heat transfer emerges in a new light,” said Hussein who also has a courtesy appointment in the Department of Physics.
The researchers, essentially, recreated their experiment from several years before, but this time, entirely on a computer. They modeled a series of silicon bars, laid side by side like the slats in a train track and heated them up.
The simulations were so detailed, Knobloch said, that the team could follow the behavior of each and every atom in the model—millions of them in all—from start to finish.
“We were really pushing the limits of memory of the Summit Supercomputer at CU Boulder,” he said.
The technique paid off. The researchers found, for example, that when they spaced their silicon bars far enough apart, heat tended to escape away from those materials in a predictable way. The energy leaked from the bars and into the material below them, dissipating in every direction.
When the bars got closer together, however, something else happened. As the heat from those sources scattered, it effectively forced that energy to flow more intensely away from the sources—like a crowd of people in a stadium jostling against each other and eventually leaping out of the exit. The team denoted this phenomenon “directional thermal channeling.”
“This phenomenon increases the transport of heat down into the substrate and away from the heat sources,” Knobloch said.
The researchers suspect that engineers could one day tap into this unusual behavior to gain a better handle on how heat flows in small electronics—directing that energy along a desired path, instead of letting it run wild and free.
For now, the researchers see the latest study as what scientists from different disciplines can do when they work together.
“This project was such an exciting collaboration between science and engineering—where advanced computational analysis methods developed by Mahmoud’s group were critical for understanding new materials behavior uncovered earlier by our group using new extreme ultraviolet quantum light sources,” said Murnane, also a professor of physics.
This breakthrough in neuromorphic (brainlike) computing is being attributed to the pandemic (COVID-19) according to a September 3, 2021 news item on phys.org,
Isaac Newton’s groundbreaking scientific productivity while isolated from the spread of bubonic plague is legendary. University of California San Diego physicists can now claim a stake in the annals of pandemic-driven science.
A team of UC San Diego [University of California San Diego] researchers and colleagues at Purdue University have now simulated the foundation of new types of artificial intelligence computing devices that mimic brain functions, an achievement that resulted from the COVID-19 pandemic lockdown. By combining new supercomputing materials with specialized oxides, the researchers successfully demonstrated the backbone of networks of circuits and devices that mirror the connectivity of neurons and synapses in biologically based neural networks.
As bandwidth demands on today’s computers and other devices reach their technological limit, scientists are working towards a future in which new materials can be orchestrated to mimic the speed and precision of animal-like nervous systems. Neuromorphic computing based on quantum materials, which display quantum-mechanics-based properties, allow scientists the ability to move beyond the limits of traditional semiconductor materials. This advanced versatility opens the door to new-age devices that are far more flexible with lower energy demands than today’s devices. Some of these efforts are being led by Department of Physics Assistant Professor Alex Frañó and other researchers in UC San Diego’s Quantum Materials for Energy Efficient Neuromorphic Computing (Q-MEEN-C), a Department of Energy-supported Energy Frontier Research Center.
“In the past 50 years we’ve seen incredible technological achievements that resulted in computers that were progressively smaller and faster—but even these devices have limits for data storage and energy consumption,” said Frañó, who served as one of the PNAS paper’s authors, along with former UC San Diego chancellor, UC president and physicist Robert Dynes. “Neuromorphic computing is inspired by the emergent processes of the millions of neurons, axons and dendrites that are connected all over our body in an extremely complex nervous system.”
As experimental physicists, Frañó and Dynes are typically busy in their laboratories using state-of-the-art instruments to explore new materials. But with the onset of the pandemic, Frañó and his colleagues were forced into isolation with concerns about how they would keep their research moving forward. They eventually came to the realization that they could advance their science from the perspective of simulations of quantum materials.
“This is a pandemic paper,” said Frañó. “My co-authors and I decided to study this issue from a more theoretical perspective so we sat down and started having weekly (Zoom-based) meetings. Eventually the idea developed and took off.”
The researchers’ innovation was based on joining two types of quantum substances—superconducting materials based on copper oxide and metal insulator transition materials that are based on nickel oxide. They created basic “loop devices” that could be precisely controlled at the nano-scale with helium and hydrogen, reflecting the way neurons and synapses are connected. Adding more of these devices that link and exchange information with each other, the simulations showed that eventually they would allow the creation of an array of networked devices that display emergent properties like an animal’s brain.
Like the brain, neuromorphic devices are being designed to enhance connections that are more important than others, similar to the way synapses weigh more important messages than others.
“It’s surprising that when you start to put in more loops, you start to see behavior that you did not expect,” said Frañó. “From this paper we can imagine doing this with six, 20 or a hundred of these devices—then it gets exponentially rich from there. Ultimately the goal is to create a very large and complex network of these devices that will have the ability to learn and adapt.”
With eased pandemic restrictions, Frañó and his colleagues are back in the laboratory, testing the theoretical simulations described in the PNAS [Proceedings of the National Academy of Sciences] paper with real-world instruments.
More than 3 million people in America have dental implants, used to replace a tooth lost to decay, gum disease, or injury. Implants represent a leap of progress over dentures or bridges, fitting much more securely and designed to last 20 years or more.
But often implants fall short of that expectation, instead needing replacement in five to 10 years due to local inflammation or gum disease, necessitating a repeat of a costly and invasive procedure for patients.
“We wanted to address this issue, and so we came up with an innovative new implant,” says Geelsu Hwang, an assistant professor in the University of Pennsylvania School of Dental Medicine, who has a background in engineering that he brings to his research on oral health issues.
The novel implant would implement two key technologies, Hwang says. One is a nanoparticle-infused material that resists bacterial colonization. And the second is an embedded light source to conduct phototherapy, powered by the natural motions of the mouth, such as chewing or toothbrushing. In a paper in the journal ACS Applied Materials & Interfaces and a 2020 paper in the journal Advanced Healthcare Materials, Hwang and colleagues lay out their platform, which could one day be integrated not only into dental implants but other technologies, such as joint replacements, as well.
“Phototherapy can address a diverse set of health issues,” says Hwang. “But once a biomaterial is implanted, it’s not practical to replace or recharge a battery. We are using a piezoelectric material, which can generate electrical power from natural oral motions to supply a light that can conduct phototherapy, and we find that it can successfully protect gingival tissue from bacterial challenge.”
In the paper, the material the researchers explored was barium titanate (BTO), which has piezoelectric properties that are leveraged in applications such as capacitators and transistors, but has not yet been explored as a foundation for anti-infectious implantable biomaterials. To test its potential as the foundation for a dental implant, the team first used discs embedded with nanoparticles of BTO and exposed them to Streptococcus mutans, a primary component of the bacterial biofilm responsible for tooth decay commonly known as dental plaque. They found that the discs resisted biofilm formation in a dose-dependent manner. Discs with higher concentrations of BTO were better at preventing biofilms from binding.
While earlier studies had suggested that BTO might kill bacteria outright using reactive oxygen species generated by light-catalyzed or electric polarization reactions, Hwang and colleagues did not find this to be the case due to the short-lived efficacy and off-target effects of these approaches. Instead, the material generates enhanced negative surface charge that repels the negatively charged cell walls of bacteria. It’s likely that this repulsion effect would be long-lasting, the researchers say.
“We wanted an implant material that could resist bacterial growth for a long time because bacterial challenges are not a one-time threat,” Hwang says.
The power-generating property of the material was sustained and in tests over time the material did not leach. It also demonstrated a level of mechanical strength comparable to other materials used in dental applications.
Finally, the material did not harm normal gingival tissue in the researchers’ experiments, supporting the idea that this could be used without ill effect in the mouth.
The technology is a finalist in the Science Center’s research accelerator program, the QED Proof-of-Concept program. As one of 12 finalists, Hwang and colleagues will receive guidance from experts in commercialization. If the project advances to be one of three finalists, the group has the potential to receive up to $200,000 in funding.
In future work, the team hopes to continue to refine the “smart” dental implant system, testing new material types and perhaps even using assymetric properties on each side of the implant components, one that encourages tissue integration on the side facing the gums and one that resists bacterial formation on the side facing the rest of the mouth.
“We hope to further develop the implant system and eventually see it commercialized so it can be used in the dental field,” Hwang says.