Engineering and Technology Updates


Engineering and Technology Updates

New method simplifies the construction process for complex materials

Engineers are constantly searching for materials with novel, desirable property combinations. For example, an ultra-strong, lightweight material could be used to make airplanes and cars more fuel-efficient, or a material that is porous and biomechanically friendly could be useful for bone implants. Cellular metamaterials — artificial structures composed of units, or cells, that repeat in various patterns — can help achieve these goals. But it is difficult to know which cellular structure will lead to the desired properties. Even if one focuses on structures made of smaller building blocks like interconnected beams or thin plates, there are an infinite number of possible arrangements to consider. So, engineers can manually explore only a small fraction of all the cellular metamaterials that are hypothetically possible. Researchers from MIT and the Institute of Science and Technology Austria have developed a computational technique that makes it easier for a user to quickly design a metamaterial cell from any of those smaller building blocks, and then evaluate the resulting metamaterial’s properties. Their approach, like a specialized CAD (computer-aided design) system for metamaterials, allows an engineer to quickly model even very complex metamaterials and experiment with designs that may have otherwise taken days to develop. The user-friendly interface also enables the user to explore the entire space of potential metamaterial shapes, since all building blocks are at their disposal. When a scientist develops a cellular metamaterial, the researcher typically begins by choosing a representation that will be used to describe her potential designs. This choice determines the set of shapes that will be available for exploration. For instance, one may choose a technique that represents metamaterials using many interconnecting beams. However, this prevents one from exploring metamaterials based on other elements, such as thin plates or 3D structures like spheres. Those shapes are given by different representations, but so far, there hasn’t been a unified way to describe all shapes in one method. The scientists took a step back and closely examined different metamaterials. They saw that the shapes that comprise the overall structure could be easily represented by lower-dimensional shapes — a beam could be reduced to a line or a thin-shell could be compressed to a flat surface. They also noticed that cellular metamaterials often have symmetries, so only a small part of the structure needs to be represented. The rest can be built by rotating and mirroring that initial piece. With their graph-based representation, a user builds a metamaterial skeleton using building blocks that are created by vertices and edges. For instance, to create a beam structure, one places a vertex at each end point of the beam and connects them with a line. Then the user employs a function over that line to specify the thickness of the beam, which can be varied so one part of the beam is thicker than another. The process for surfaces is similar — the user marks the most important features with vertices and then chooses a solver that infers the rest of the surface. These easy-to-use solvers even allow users to quickly construct a highly complex type of metamaterial, called a triply periodic minimal surface (TPMS). These structures are incredibly powerful, but the usual process to develop them is arduous and prone to failure. At the end of the process, the system outputs the entire graph-based procedure, showing every operation the user took to reach the final structure — all the vertices, edges, solvers, transformations, and thickening operations.Within the user interface, designers can preview the current structure at any point in the building procedure and directly predict certain properties, such as its stiffness. Then, the user can iteratively tweak some parameters and evaluate it again until a suitable design is reached. The researchers used their system to recreate structures that spanned many unique classes of metamaterials. Once they had designed the skeletons, each metamaterial structure took only seconds to generate. They also created automated exploration algorithms, giving each a set of rules and then turning it loose in their system. In one test, an algorithm returned more than 1,000 potential truss-based structures in about an hour. In addition, the researchers conducted a user-study with 10 individuals who had little prior experience modeling metamaterials. The users were able to successfully model all six structures they were given, and most agreed that the procedural graph representation made the process easier.

Source: https://www.sciencedaily.com/releases/2023/08/230802132059.htm

Denial of service threats detected thanks to asymmetric behavior in network traffic

Scientists have developed a better way to recognize a common internet attack, improving detection by 90 percent compared to current methods. The new technique developed by computer scientists at the Department of Energy’s Pacific Northwest National Laboratory works by keeping a watchful eye over ever-changing traffic patterns on the internet. The scientists modified the playbook most commonly used to detect denial-of-service attacks, where perpetrators try to shut down a website by bombarding it with requests. Motives vary: Attackers might hold a website for ransom, or their aim might be to disrupt businesses or users. Many systems try to detect such attacks by relying on a raw number called a threshold. If the number of users trying to access a site rises above that number, an attack is considered likely, and defensive measures are triggered. But relying on a threshold can leave systems vulnerable. A threshold can also create false alarms that have serious consequences themselves. False positives can force defenders to take a site offline and bring legitimate traffic to a standstill — effectively doing what a real denial-of-service attack, also known as a DOS attack, aims to do. To improve detection accuracy, the PNNL team sidestepped the concept of thresholds completely. Instead, the team focused on the evolution of entropy, a measure of disorder in a system. Usually on the internet, there’s consistent disorder everywhere. But during a denial-of-service attack, two measures of entropy go in opposite directions. At the target address, many more clicks than usual are going to one place, a state of low entropy. But the sources of those clicks, whether people, zombies or bots, originate in many different places — high entropy. The mismatch could signify an attack. In PNNL’s testing, 10 standard algorithms correctly identified on average 52 percent of DOS attacks; the best one correctly identified 62 percent of attacks. The PNNL formula correctly identified 99 percent of such attacks. The improvement isn’t due only to the avoidance of thresholds. To improve accuracy further, the PNNL team added a twist by not only looking at static entropy levels but also watching trends as they change over time. In addition, the researcher explored alternative options to calculate entropy. Many denial-of-service detection algorithms rely on a formula known as Shannon entropy. They instead settled on a formula known as Tsallis entropy for some of the underlying mathematics. Researchers found that the Tsallis formula is hundreds of times more sensitive than Shannon at weeding out false alarms and differentiating legitimate flash events, such as high traffic to a World Cup website, from an attack. That’s because the Tsallis formula amplifies differences in entropy rates more than the Shannon formula. Think of how we measure temperature. If our thermometer had a resolution of 200 degrees, our outdoor temperature would always appear to be the same. But if the resolution were 2 degrees or less-like most thermometers-we’d detect dips and spikes many times each day. They showed that it’s similar with subtle changes in entropy, detectable through one formula but not the other. The PNNL solution is automated and doesn’t require close oversight by a human to distinguish between legitimate traffic and an attack. The researchers say that their program is “lightweight” — it doesn’t need much computing power or network resources to do its job. This is different from solutions based on machine learning and artificial intelligence, said the researchers. While those approaches also avoid thresholds, they require a large amount of training data. Now, the PNNL team is looking at how the buildout of 5G networking and the booming internet of things landscape will have an impact on denial-of-service attacks.

Source: https://www.sciencedaily.com/releases/2023/08/230803132226.htm

Robotic grippers offer unprecedented combo of strength and delicacy

Researchers at North Carolina State University have developed a robotic gripping device that is gentle enough to pick up a drop of water, strong enough to pick up a 6.4kilogram (14.1 pound) weight, dexterous enough to fold a cloth, and precise enough to pick up microfilms that are 20 times thinner than a human hair. In addition to possible manufacturing applications, the researchers also integrated the device with technology that allows the gripper to be controlled by the electrical signals produced by muscles in the forearm, demonstrating its potential for use with robotic prosthetics. The design for the new grippers builds on an earlier generation of flexible, robotic grippers that drew on the art of kirigami, which involves both cutting and folding two-dimensional sheets of material to form three-dimensional shapes. The new design is able to achieve high degrees of strength and gentleness because of how it distributes force throughout the structure of the gripper. “The strength of robotic grippers is generally measured in payload-to-weight ratio,” a researcher says. “Our grippers weigh 0.4 grams and can lift up to 6.4 kilograms. That’s a payload-to-weight ratio of about 16,000. That is 2.5 times higher than the previous record for payload-to-weight ratio, which was 6,400. Combined with its characteristics of gentleness and precision, the strength of the grippers suggests a wide variety of applications.” Another benefit of the new technology is that its attractive characteristics are driven primarily by its structural design, rather than by the materials used to fabricate the grippers. “In practical terms, this means that you could fabricate the grippers out of biodegradable materials, such as sturdy plant leaves,” says another researcher. “That could be particularly useful for applications where you would only want to use the grippers for a limited period of time, such as when handling food or biomedical materials. For example, we’ve demonstrated that the grippers can be used to handle sharp medical waste, such as needles.” The researchers also integrated the gripping device with a myoelectric prosthetic hand, meaning the prosthesis is controlled using muscle activity. The new gripper can’t replace all of the functions of existing prosthetic hands, but it could be used to supplement those other functions. One of the advantages of the kirigami grippers is that you would not need to replace or augment the existing motors used in robotic prosthetics. You could simply make use of the existing motor when utilizing the grippers. In proof-of-concept testing, the researchers demonstrated that the kirigami grippers could be used in conjunction with the myoelectric prosthesis to turn the pages of a book and pluck grapes off a vine.”We think the gripper design has potential applications in fields ranging from robotic prosthetics and food processing to pharmaceutical and electronics manufacturing,” a researcher says. “We are looking forward to working with industry partners to find ways to put the technology to use.”

Source: https://www.sciencedaily.com/releases/2023/08/230802132108.htm

New, simple and accessible method creates potency-increasing structure in drugs

Chemical structures called cyclopropanes can increase the potency and fine-tune the properties of many drugs, but traditional methods to create this structure only work with certain molecules and require highly reactive — potentially explosive — ingredients. Now, a team of researchers from Penn State has identified and demonstrated a safe, efficient and practical way to create cyclopropanes on a wide variety of molecules using a previously undescribed chemical process. With additional development, the new method could transform how this important process occurs during drug development and creation. Cyclopropanes are a key feature in many drugs currently approved by the U.S. Food and Drug Administration, including those used to treat COVID-19, asthma, hepatitis C, and HIV/AIDs. These structures can increase a drug’s potency, alter its ability to dissolve in the body, minimize its interactions with unintended targets, and otherwise fine-tune performance. Cyclopropanes are a ring of three connected carbon atoms, with one carbon attached to the rest of the drug molecule and the other two each attached to two hydrogen atoms. “Cyclopropanes are an essential component of many drugs and adding them to drug candidates can be an important part of the drug discovery process,” said Ramesh Giri, professor of chemistry in the Eberly College of Science at Penn State and leader of the research team. “Previous efforts to improve the creation of cyclopropanes have focused on altering a mechanistic pathway devolved more than 60 years ago. We approached this from a different angle and identified a completely new pathway that is a simple, practical, and broadly applicable.” The new method transforms a specific chemical structure on compounds called alkenes — used in the synthesis of many molecules — into cyclopropanes. The method takes advantage of “radical chemistry,” where intermediate steps of reactions leave some carbon atoms with unpaired electrons called free radicals that propel the reaction forward. This specific method uses visible light to initiate the reaction and uses common chemical ingredients, including oxygen. Traditional methods to create cyclopropanes require highly reactive and difficult-to-acquire ingredients and must be conducted under controlled conditions, and the resulting compounds often have a very short shelf life. These unstable ingredients are critical to producing an intermediate compound in the process called a carbene — a highly reactive carbon atom with two unpaired electrons. The new method completely bypasses the carbene intermediate, producing the unpaired electrons one at a time as radicals. “All of the ingredients used in this pathway are commercially available or easy to create in the lab and do not require any special safety precautions, and the end product can be stored for prolonged periods,” Giri said. “We can add all the ingredients together in one mixture while exposed to air with as little as 10% oxygen, and it proceeds in one step. The reaction is simple and safe enough that we are even planning to include it as part of an undergraduate chemistry lab.” Another shortcoming of traditional methods is that they generally do not work with complex molecules. For this reason, cyclopropanes are typically installed early in the synthesis when the molecule is less complex but following steps can cause the ring to open up, and later attempts to make derivatives of the molecule would require backtracking to those early steps. Using the new method, the researchers successfully transformed a variety of alkenes with a wide range of complexities into cyclopropanes, including pharmaceutically relevant compounds such as the steroid estrone, penicillin and vitamin B. Some of the ingredients in the reaction can also be swapped out to add additional chemical groups to the final product to achieve various therapeutic goals. One of the reaction’s ingredients is as a type of compound called a methylene. There are hundreds of different methylenes that are commercially available, each with a specific chemical group that makes it a methylene as well as other groups that differ and could theoretically be added to the alkene as a cyclopropane Is created. The researchers demonstrated the breadth of the new method using 19 different methylene compounds. Next, Giri and his lab plan to scale up the method so that it is industrially viable.

Source: https://www.sciencedaily.com/releases/2023/08/230803141658.htm

Thermal imaging innovation allows AI to see through pitch darkness like broad daylight

Researchers at Purdue University are advancing the world of robotics and autonomy with their patent-pending method that improves on traditional machine vision and perception. Zubin Jacob, the Elmore Associate Professor of Electrical and Computer Engineering in the Elmore Family School of Electrical and Computer Engineering, and research scientist Fanglin Bao have developed HADAR, or heat-assisted detection and ranging. Jacob said it is expected that one in 10 vehicles will be automated and that there will be 20 million robot helpers that serve people by 2030. “Each of these agents will collect information about its surrounding scene through advanced sensors to make decisions without human intervention,” Jacob said. “However, simultaneous perception of the scene by numerous agents is fundamentally prohibitive.” Traditional active sensors like LiDAR, or light detection and ranging, radar and sonar emit signals and subsequently receive them to collect 3D information about a scene. These methods have drawbacks that increase as they are scaled up, including signal interference and risks to people’s eye safety. In comparison, video cameras that work based on sunlight or other sources of illumination are advantageous, but low-light conditions such as night-time, fog or rain present a serious impediment. Traditional thermal imaging is a fully passive sensing method that collects invisible heat radiation originating from all objects in a scene. It can sense through darkness, inclement weather and solar glare. But Jacob said fundamental challenges hinder its use today. HADAR combines thermal physics, infrared imaging and machine learning to pave the way to fully passive and physics-aware machine perception. “Our work builds the information theoretic foundations of thermal perception to show that pitch darkness carries the same amount of information as broad daylight. Evolution has made human beings biased toward the daytime. Machine perception of the future will overcome this long-standing dichotomy between day and night,” Jacob said. Bao said, “HADAR vividly recovers the texture from the cluttered heat signal and accurately disentangles temperature, emissivity and texture, or TeX, of all objects in a scene. It sees texture and depth through the darkness as if it were day and also perceives physical attributes beyond RGB, or red, green and blue, visible imaging or conventional thermal sensing. It is surprising that it is possible to see through pitch darkness like broad daylight.” The team tested HADAR TeX vision using an off-road night-time scene. “HADAR TeX vision recovered textures and overcame the ghosting effect,” Bao said. “It recovered fine textures such as water ripples, bark wrinkles and culverts in addition to details about the grassy land.” Additional improvements to HADAR are improving the size of the hardware and the data collection speed. “The current sensor is large and heavy since HADAR algorithms require many colours of invisible infrared radiation,” Bao said. “To apply it to self-driving cars or robots, we need to bring down the size and price while also making the cameras faster. The current sensor takes around one second to create one image, but for autonomous cars we need around 30 to 60 hertz frame rates, or frames per second.” HADAR TeX vision’s initial applications are automated vehicles and robots that interact with humans in complex environments. The technology could be further developed for agriculture, defence, geosciences, health care and wildlife monitoring applications.

Source: https://www.sciencedaily.com/releases/2023/08/230801131652.htm

The Low Earth Orbit Satellite Space Race: Starlink Versus AST SpaceMobile

Today, a new space race is emerging in telecommunications. Low earth orbit (LEO) satellite constellations promise to disrupt mature, higher-altitude geosynchronous earth orbit (GEO) deployments. The communications advantages of LEO are undeniable—lower latency given the shorter distance, lower power requirements and flexibility, because unlike GEO, the technology does not require a fixed connection point. GEO’s limitations have also made it very expensive for subscribers and challenging to scale, given the significant investment required in both satellite construction and terrestrial infrastructure. The latter is what LEO hopes to disrupt. Starlink and AST SpaceMobile are emerging as the early front-runners in the LEO telecommunications world. Starlink probably needs no introduction, given its association with Musk’s SpaceX operations. It offers broadband internet services to rural locations underserved by cable, fiber, LTE and 5G fixed wireless access services, and is supported by more than 4,000 satellites launched to date. In the long term, Musk promises to raise that number to 30,000 birds in the sky with a reusable design that aims to lower the cost of satellite construction. With that said, Musk has a track record of over-promises and under-delivery, as evidenced in his Tesla operations and recent stumbles with SpaceX. One of the other significant challenges is that Starlink’s initial service has been fraught with both expensive consumer premise equipment and poor performance. These challenges could resolve themselves over time with scale, but the company’s partnership announcement with T-Mobile late last year might be premature. Initially, the Starlink service is focused on enabling emergency text messaging in areas lacking coverage using T-Mobile’s mid-band spectrum assets, with plans to add voice and data later. What needs to be clarified now are the specific deployment plans and whether they could create interference with terrestrial mobile networks. Avellan has laid a solid foundation for AST SpaceMobile. It is rooted in a direct-to-device connection, unlike Starlink’s focus on fixed-point broadband services. However, Starlink seems to be moving beyond that focus, considering that it now also offers a mobility solution for recreational vehicles. So far, AST SpaceMobile has launched two LEO satellites, and the second one integrates phased-array and digital beam-forming technologies to focus and pinpoint signals more accurately. However, more satellite launches are planned in the future. AST SpaceMobile has also signed agreements and understandings with more than 35 mobile network operators globally, including AT&T in the U.S., and the company is content to serve as a wholesaler to provide connectivity gap coverage. That gives AST SpaceMobile a decided edge over Starlink in driving scale and adoption; the wholesaler approach will allow it to serve a large swath of operators to monetize services, including fixed wireless access broadband, where Starlink is a direct competitor. Maybe the most powerful proof suggesting AST SpaceMobile’s potential to lead in LEO was the first smartphone-to-satellite phone call, made in April on a Samsung device over the AT&T network. The latter is an extraordinary accomplishment that eclipses emergency text messaging support. LEO satellite connectivity will play a major role in bridging the digital divide for nearly three billion people globally who don’t have access to the internet.

Source: https://www.forbes.com/sites/moorinsights/2023/06/15/the-low-earth-orbit-satellite-space-race-starlink-versus-ast-spacemobile/

India ISRO’s Aditya-L1 solar mission reaches destination

The Indian Space Research Organisation’s inaugural solar mission, Aditya-L1, has reached its destination within the anticipated four-month timeframe. Launched on September 2, 2023 the spacecraft positioned itself at Lagrange Point 1, from where it will undertake a comprehensive study of the sun, focusing on the solar corona and its influence on space weather. The satellite covered approximately 1.5 million kilometers (930,000 miles) over the span of four months, just a fraction of the Earth-sun distance of 150 million kilometers. The Lagrange Point, where the satellite is stationed, benefits from gravitational forces that allow objects to remain relatively stationary, reducing fuel consumption for the spacecraft. Equipped with seven payloads, Aditya-L1 is slated to conduct remote sensing of the sun and in-situ observations for an estimated five years. Named after the Hindi word for the sun, this mission follows India’s recent achievement of being the first country to successfully land on the moon’s south pole, surpassing Russia’s failed Luna-25 with the Chandrayaan-3 mission. Chandrayaan-3 landed on the unexplored south pole of the moon in August last year. Scientists involved in the project aim to gain insights into the impact of solar radiation on the increasing number of satellites in orbit, with a particular focus on phenomena affecting ventures like Elon Musk’s Starlink communications network. The low earth orbit is going to get “super” crowded over the coming years, said an engineer. “Satellites are going to become the main stay of all tech on Earth with Quantum implemented, with internet connectivity, disaster warning system, resource utilisation and many more applications,” he said. Stationing a spacecraft at L1 acts as an early warning system, with roughly one-hour advantage, for an upcoming storm from the Sun, he said. The mission to study the sun is among a slate of projects ISRO has lined up through the year, key among them its first human space mission and a low-Earth orbit observatory system jointly developed by NASA and ISRO, called NISAR. NISAR will map the entire planet once every 12 days, providing data for understanding changes in ecosystems, ice mass, vegetation biomass, sea level rise, ground water and natural hazards including earthquakes, tsunamis, volcanoes and landslides.

Source: https://www.reuters.com/science/india-isros-aditya-l1-solar-mission-reaches-destination-2024-01-06/

Butterfly-inspired films create vibrant colors while passively cooling objects

On a hot summer day, white clothing feels cooler than other colours due to reflecting — not absorbing — sunlight. Other colours like blue or black, will undergo a heating effect as they absorb light. To circumvent this heating effect in coloured cooling films, researchers drew inspiration from nanostructures in butterfly wings. The new films, which don’t absorb any light, could be used on the outside of buildings, vehicles and equipment to reduce the energy needed for cooling while preserving vivid colour properties. The researchers showed that the films they developed lower the temperature of colourful objects to about 2 °C below the ambient temperature. They also found that when left outside all day, the blue version of the films was approximately 26°C cooler than traditional blue car paint. This represents an annual energy savings of approximately 1377 MJ/m2 per year. A car with blue paint appears blue because it absorbs yellow light and reflects blue light. The large amount of light that is absorbed heats the car. Morpho butterflies, however, produce their highly saturated blue colour based on the nanostructure of their wings. The design of the cooling nanofilm mimics these structures to produce vibrant colours that don’t absorb light like traditional paint. To create their Morpho-inspired nanofilms, the researchers placed a disordered material (rough frosted glass) under a multilayer material made of titanium dioxide and aluminium dioxide. They then placed this structure on a silver layer that reflects all light, thus preventing the absorption of solar radiation and the heating associated with that absorption. The film’s colour is determined by how components within its multi-layered structure reflect light. To create blue, for example, the multilayer material is designed to reflect yellow light in a very narrow range of angles while the disordered structure diffuses the blue light across a broad area. Although this type of passive photonic thermal management has been accomplished before, it has only been used with white or clear objects because it is difficult to maintain a wide viewing angle and high colour saturation. To test the new technology, the researchers created blue, yellow and colourless films, which they placed outdoors at Shenzhen University, on surfaces such as roofs, cars, cloth and cell phones, from 9 a.m. to 4 p.m. in both winter and summer. Using thermocouple sensors and infrared cameras to measure temperature, they found that the cooling films were much cooler than the surfaces they were placed on in the winter and further cooler in the summer. The researchers point out that replacing the silver film with an aluminium film would make the films less expensive and manufacturable by a scalable fabrication method such as electron beam evaporation and magnetron sputtering. Now that they have demonstrated the cooling and colour performance of the films, the researchers plan to study and optimize other properties such as mechanical and chemical robustness.

Source: https://www.sciencedaily.com/releases/2023/08/230803112920.htm

Faster thin film devices for energy storage and electronics

An international research team from the Max Planck Institute of Microstructure Physics, Halle (Saale), Germany, the University of Cambridge, UK and the University of Pennsylvania, USA reported the first realization of single-crystalline T-Nb2O5 thin films having two-dimensional (2D) vertical ionic transport channels, which results in a fast and colossal insulator-metal transition via Li ion intercalation through the 2D channels. Since the 1940s, scientists have been exploring the use of niobium oxide, specifically a form of niobium oxide known as T-Nb2O5, to create more efficient batteries. This unique material is known for its ability to allow lithium ions, the tiny charged particles that make batteries work, to move quickly within it. The faster these lithium ions can move, the faster a battery can be charged. The challenge, however, has always been to grow this niobium oxide material into thin, flat layers, or ‘films’ that are of high enough quality to be used in practical applications. This problem stems from the complex structure of T-Nb2O5 and the existence of many similar forms, or polymorphs, of niobium oxide. Researchers from the Max Planck Institute of Microstructure Physics, University of Cambridge and the University of Pennsylvania have successfully demonstrated the growth of high-quality, single-crystal thin films of T-Nb2O5, aligned in such a way that the lithium ions can move even faster along vertical ionic transport channels. The T-Nb2O5 films undergo a significant electrical change at an early stage of Li insertion into the initially insulating films. This is a dramatic shift — the resistivity of the material decreases by a factor of 100 billion. The research team further demonstrate tunable and low voltage operation of thin film devices by altering the chemical composition of the ‘gate’ electrode, a component that controls the flow of ions in a device, further extending the potential applications. The Max Planck Institute of Microstructure Physics group realized the growth of the single-crystalline T-Nb2O5 thin films and showed how Li-ion intercalation can dramatically increase their electrical conductivity. Together with the University of Cambridge group multiple previously unknown transitions in the material’s structure were discovered as the concentration of lithium ions was changed. These transitions change the electronic properties of the material, allowing it to switch from being an insulator to a metal, meaning that it goes from blocking electric current to conducting it. Researchers from the University of Pennsylvania rationalized the multiple phase transitions they observed, as well as, how these phases might be related to the concentration of lithium ions and their arrangement within the crystal structure. These results could only have been successful through synergies between the three international groups with diverse specialties: thin films from the Max Planck Institute of Microstructure Physics, batteries from the University of Cambridge, and theory from the University of Pennsylvania. The ability to control the orientation of these films allows the researches to explore anisotropic transport in this technologically-important class of materials, which is fundamental to the understanding of how these materials operate.

Source: https://www.sciencedaily.com/releases/2023/08/230802105803.htm

Surgical and engineering innovations enable unprecedented control over every finger of a bionic hand

Prosthetic limbs are the most common solution to replace a lost extremity. However, they are hard to control and often unreliable with only a couple of movements available. Remnant muscles in the residual limb are the preferred source of control for bionic hands. This is because patients can contract muscles at will, and the electrical activity generated by the contractions can be used to tell the prosthetic hand what to do, for instance, open or close. A major problem at higher amputation levels, such as above the elbow, is that not many muscles remain to command the many robotic joints needed to truly restore the function of an arm and hand. A multidisciplinary team of surgeons and engineers has circumvented this problem by reconfiguring the residual limb and integrating sensors and a skeletal implant to connect with a prosthesis electrically and mechanically. By dissecting the peripheral nerves and redistributing them to new muscle targets used as biological amplifiers, the bionic prosthesis can now access much more information, so the user can command many robotic joints at will. The research was led by Professor Max Ortiz Catalan, Founding Director of the Centre for Bionics and Pain Research (CBPR) in Sweden, Head of Neural Prosthetics Research at the Bionics Institute in Australia, and Professor of Bionics at Chalmers University of Technology in Sweden. The researchers show that rewiring nerves to different muscle targets in a distributed and concurrent manner is not only possible but also conducive to improved prosthetic control. A key feature of the work is that they have the possibility to clinically implement more refine surgical procedures and embed sensors in the neuromuscular constructs at the time of the surgery, which is then connected to the electronic system of the prosthesis via an osseo-integrated interface. A.I. algorithms take care of the rest. Prosthetic limbs are commonly attached to the body by a socket that compresses the residual limb causing discomfort and is mechanically unstable. An alternative to socket attachment is to use a titanium implant placed within the residual bone which becomes strongly anchored — this is known as osseointegration. Such skeletal attachment allows for comfortable and more efficient mechanical connection of the prosthesis to the body. The cutting-edge surgical and engineering innovation can provide a high level of functionality for an individual with an arm amputation. The surgery took place at the Sahlgrenska University Hospital, Sweden, where CBPR is located. The neuromuscular reconstruction procedure was conducted by Dr. Paolo Sassu, who also led the first hand transplantation performed in Scandinavia. “The incredible journey we have undertaken together with the bionic engineers at CBPR has allowed us to combine new microsurgical techniques with sophisticated implanted electrodes that provide single-finger control of a prosthetic arm as well as sensory feedback. Patients who have suffered from an arm amputation might now see a brighter future,” says Dr. Sassu, who is presently working at the Istituto Ortopedico Rizzoli in Italy. The research article illustrates how the transferred nerves progressively connected to their new hosting muscles. Once the innervation process had advanced enough, the researchers connected them to the prosthesis, so the patient could control every finger of a prosthetic hand as if it would be his own. The researchers also demonstrated how the system respond in activities of the daily life and are currently in the process of further improving the controllability of the bionic hand.

Source: https://www.sciencedaily.com/releases/2023/07/230712165138.htm