How to Restore Walking After Spinal Cord Injury

A new study by scientists at the .NeuroRestore research center has identified the type of neuron that is activated and remodeled by spinal cord stimulation, allowing patients to stand up, walk and rebuild their muscles – thus improving their quality of life. This discovery, made in  nine patients, marks a fundamental, clinical breakthrough.

In a multi-year research program coordinated by the two directors of  .NeuroRestore – Grégoire Courtine, a neuroscience professor at EPFL, and  Jocelyne Bloch, a neurosurgeon at Lausanne University Hospital (CHUV) – patients who had been paralyzed by a spinal cord injury and who underwent  targeted epidural electrical stimulation of the area that controls leg movement  were able to regain some motor function.

You must be logged in to view this content.

AI Can Control SuperHeated Plasma Inside a Fusion Reactor

DeepMind’s streak of applying its world-class AI to hard science problems continues. In collaboration with the Swiss Plasma Center at EPFL—a university in Lausanne, Switzerland—the UK-based AI firm has now trained a deep reinforcement learning algorithm to control the superheated soup of matter inside a nuclear fusion reactor. The breakthrough, published in the journal Nature, could help physicists better understand how fusion works, and potentially speed up the arrival of an unlimited source of clean energy.

This is one of the most challenging applications of reinforcement learning to a real-world system,” says Martin Riedmiller, a researcher at DeepMind.

In nuclear fusion, the atomic nuclei of hydrogen atoms get forced together to form heavier atoms, like helium. This produces a lot of energy relative to a tiny amount of fuel, making it a very efficient source of power. It is far cleaner and safer than fossil fuels or conventional nuclear power, which is created by fissionforcing nuclei apart. It is also the process that powers stars.

Controlling nuclear fusion on Earth is hard, however. The problem is that atomic nuclei repel each other. Smashing them together inside a reactor can only be done at extremely high temperatures, often reaching hundreds of millions of degreeshotter than the center of the sun. At these temperatures, matter is neither solid, liquid, nor gas. It enters a fourth state, known as plasma: a roiling, superheated soup of particles.

The task is to hold the plasma inside a reactor together long enough to extract energy from it. Inside stars, plasma is held together by gravity. On Earth, researchers use a variety of tricks, including lasers and magnets. In a magnet-based reactor, known as a tokamak, the plasma is trapped inside an electromagnetic cage, forcing it to hold its shape and stopping it from touching the reactor walls, which would cool the plasma and damage the reactor. Controlling the plasma requires constant monitoring and manipulation of the magnetic field. The team trained its reinforcement-learning algorithm to do this inside a simulation. Once it had learned how to control—and change—the shape of the plasma inside a virtual reactor, the researchers gave it control of the magnets in the Variable Configuration Tokamak (TCV), an experimental reactor in Lausanne. They found that the AI was able to control the real reactor without any additional fine-tuning. In total, the AI controlled the plasma for only two seconds—but this is as long as the TCV reactor can run before getting too hot.


Mind-controlled Robots

Two EPFL research groups teamed up to develop a machine-learning program that can be connected to a human brain and used to command a robot. The program adjusts the robot’s movements based on electrical signals from the brain. The hope is that with this invention, tetraplegic patients will be able to carry out more day-to-day activities on their own. Tetraplegic patients are prisoners of their own bodies, unable to speak or perform the slightest movement. Researchers have been working for years to develop systems that can help these patients carry out some tasks on their own.

People with a spinal cord injury often experience permanent neurological deficits and severe motor disabilities that prevent them from performing even the simplest tasks, such as grasping an object,” says Prof. Aude Billard, the head of EPFL’s Learning Algorithms and Systems Laboratory. “Assistance from robots could help these people recover some of their lost dexterity, since the robot can execute tasks in their place.”

Prof. Billard carried out a study with Prof. José del R. Millán, who at the time was the head of EPFL’s Brain-Machine Interface Laboratory but has since moved to the University of Texas. The two research groups have developed a computer program that can control a robot using electrical signals emitted by a patient’s brain. No voice control or touch function is needed; patients can move the robot simply with their thoughts. The study has been published in Communications Biology, an open-access journal from Nature Portfolio.

To develop their system, the researchers started with a robotic arm that had been developed several years ago. This arm can move back and forth from right to left, reposition objects in front of it and get around objects in its path. “In our study we programmed a robot to avoid obstacles, but we could have selected any other kind of task, like filling a glass of water or pushing or pulling an object,” says Prof. Billard. This entailed developing an algorithm that could adjust the robot’s movements based only on a patient’s thoughts. The algorithm was connected to a headcap equipped with electrodes for running electroencephalogram (EEG) scans of a patient’s brain activity. To use the system, all the patient needs to do is look at the robot. If the robot makes an incorrect move, the patient’s brain will emit an “error message” through a clearly identifiable signal, as if the patient is saying “No, not like that.” The robot will then understand that what it’s doing is wrong – but at first it won’t know exactly why. For instance, did it get too close to, or too far away from, the object? To help the robot find the right answer, the error message is fed into the algorithm, which uses an inverse reinforcement learning approach to work out what the patient wants and what actions the robot needs to take. This is done through a trial-and-error process whereby the robot tries out different movements to see which one is correct.

The process goes pretty quickly – only three to five attempts are usually needed for the robot to figure out the right response and execute the patient’s wishes. “The robot’s AI program can learn rapidly, but you have to tell it when it makes a mistake so that it can correct its behavior,” says Prof. Millán. “Developing the detection technology for error signals was one of the biggest technical challenges we faced.” Iason Batzianoulis, the study’s lead author, adds: “What was particularly difficult in our study was linking a patient’s brain activity to the robot’s control system – or in other words, ‘translating’ a patient’s brain signals into actions performed by the robot. We did that by using machine learning to link a given brain signal to a specific task. Then we associated the tasks with individual robot controls so that the robot does what the patient has in mind.


There’s No Theoretical Limit to Human Lifespan, New Study Says

Humans can probably live to at least 130, and possibly well beyond, though the chances of reaching such super old age remain vanishingly small, according to new research. The outer limit of the human lifespan has long been hotly debated, with recent studies making the case we could live up to 150 years, or arguing that there is no maximum theoretical age for humans.

The new research, published Wednesday in the Royal Society Open Science journal, wades into the debate by analyzing new data on supercentenarians – people aged 110 or more – and semi-supercentenarians, aged 105 or more.While the risk of death generally increases throughout our lifetime, the researchers’ analysis shows that risk eventually plateaus and remains constant at approximately 50-50.

Beyond age 110 one can think of living another year as being almost like flipping a fair coin,” said Anthony Davison, a professor of statistics at the Swiss Federal Institute of Technology in Lausanne (EPFL), who led the research. “If it comes up heads, then you live to your next birthday, and if not, then you will die at some point within the next year,” he told AFP. Based on the data available so far, it seems likely that humans can live until at least 130, but extrapolating from the findings “would imply that there is no limit to the human lifespan,” the research concludes.

The conclusions match similar statistical analyses done on datasets of the very elderly. “But this study strengthens those conclusions and makes them more precise because more data are now available,” Davison said.


New Molecule Kills The Flu Virus

Influenza is one of the most widespread viral diseases and constitutes a major public health problem. For some, it means spending a week in bed; for others, it could lead to hospitalization or, in the most severe cases, death. Scientists at the Ecole Polytechnique Fédérale de Lausanne (EPFL)’s Supramolecular Nano-Materials and Interfaces Laboratory (SuNMIL) within the School of Engineering, working in association with the team headed by Caroline Tapparel, a professor at the University of Geneva’s Department of Microbiology and Molecular Medicine, have synthesized a compound that can kill the virus that causes influenza. Their discovery paves the way to effective drug therapies against the seasonal disease.

With the flu virus, the risk of a pandemic is high,” says Francesco Stellacci, the EPFL professor who heads SuNMIL. “Scientists have to update the vaccine every year because the strain mutates, and sometimes the vaccine turns out to be less effective. So it would be good to also have antivirals that could limit the effects of large-scale infection.

“Antiviral drugs already exist, and Tamiflu is the most well-known. But it has one major drawback – it has to be taken within 36 hours of infection or it loses its efficacy completely. And with influenza, symptoms generally start appearing 24 hours after infection. “By the time patients seek medical treatment, it’s often too late for Tamiflu,” explained Stellacci. “In addition, for antivirals to really work, they have to be virucidal – that is, they have to irreversibly inhibit viral infectivity. But today that’s not the case.

The research has been published in Advanced Science.


How To Protect Cells From Premature Aging

Molecules that accumulate at the tip of chromosomes are known to play a key role in preventing damage to our DNA. Now, researchers at EPFL (Ecole Polytechnique Fédérale de Lausanne in Switzerland) have unraveled how these molecules home in on specific sections of chromosomes—a finding that could help to better understand the processes that regulate cell survival in aging and cancer.

Much like an aglet of a shoelace prevents the end of the lace from fraying, stretches of DNA called telomeres form protective caps at the ends of chromosomes. But as cells divide, telomeres become shorter, making the protective cap less effective. Once telomeres get too short, the cell stops dividing. Telomere shortening and malfunction have been linked to cell aging and age-related diseases, including cancer.

A new study by EPFL researchers shows how RNA species called TERRA muster at the tip of chromosomes, where they help to prevent telomere shortening and premature cell aging

Scientists have known that RNA species called TERRA help to regulate the length and function of telomeres. Discovered in 2007 by postdoc Claus Azzalin in the team of EPFL Professor Joachim Lingner, TERRA belongs to a class of molecules called noncoding RNAs, which are not translated into proteins but function as structural components of chromosomes. TERRA accumulates at chromosome ends, signaling that telomeres should be elongated or repaired.

However, it was unclear how TERRA got to the tip of chromosomes and remained there. “The telomere makes up only a tiny bit of the total chromosomal DNA, so the question is ‘how does this RNA find its home?’”, Lingner says. To address this question, postdoc Marianna Feretzaki and others in the teams of Joachim Lingner at EPFL and Lumir Krejci at Masaryk University set out to analyze the mechanism through which TERRA accumulates at telomeres, as well as the proteins involved in this process. The findings are published in Nature.

By visualizing TERRA molecules under a microscope, the researchers found that a short stretch of the RNA is crucial to bring it to telomeres. Further experiments showed that once TERRA reaches the tip of chromosomes, several proteins regulate its association with telomeres. Among these proteins, one called RAD51 plays a particularly important role, Lingner says.

RAD51 is a well-known enzyme that is involved in the repair of broken DNA molecules. The protein also seems to help TERRA stick to telomeric DNA to form a so-called “RNA-DNA hybrid molecule”. Scientists thought this type of reaction, which leads to the formation of a three-stranded nucleic acid structure, mainly happened during DNA repair. The new study shows that it can also happen at chromosome ends when TERRA binds to telomeres. “This is paradigm-shifting,” Lingner says.

The researchers also found that short telomeres recruit TERRA much more efficiently than long telomeres. Although the mechanism behind this phenomenon is unclear, the researchers hypothesize that when telomeres get too short, either due to DNA damage or because the cell has divided too many times, they recruit TERRA molecules. This recruitment is mediated by RAD51, which also promotes the elongation and repair of telomeres. “TERRA and RAD51 help to prevent accidental loss or shortening of telomeres,” Lingner says. “That’s an important function.”


Nanodevice 100 Times Faster Than The Usual Transistor

Researchers at Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have developed a nanodevice that operates more than 10 times faster than today’s fastest transistors, and about 100 times faster than the transistors you have on your computers. This new device enables the generation of high-power terahertz waves. These waves, which are notoriously difficult to produce, are useful in a rich variety of applications ranging from imaging and sensing to high-speed wireless communications. The high-power picosecond operation of these device also hold immense promise to some advanced medical treatment techniques such as cancer therapy. The team’s pioneering compact source, described today in Nature, paves the way for untold new applications.

Terahertz (THz) waves fall between microwave and infrared radiation in the electromagnetic spectrum, oscillating at frequencies of between 100 billion and 30 trillion cycles per second. These waves are prized for their distinctive properties: they can penetrate paper, clothing, wood and walls, as well as detect air pollution. THz sources could revolutionize security and medical imaging systems.

What’s more, their ability to carry vast quantities of data could hold the key to faster wireless communications.

THz waves are a type of non-ionizing radiation, meaning they pose no risk to human health. The technology is already used in some airports to scan passengers and detect dangerous objects and substances.

Despite holding great promise, THz waves are not widely used because they are costly and cumbersome to generate. But new technology developed by researchers at EPFL could change all that. The team at the Power and Wide-band-gap Electronics Research Laboratory (POWERlab), led by Prof. Elison Matioli, built a nanodevice (1 nanometer = 1 millionth of a millimeter) that can generate extremely high-power signals in just a few picoseconds, or one trillionth of a second, – which produces high-power THz waves.

The technology, which can be mounted on a chip or a flexible medium, could one day be installed in smartphones and other hand-held devices. The work first-authored by Mohammad Samizadeh Nikoo, a PhD student at the POWERlab, has been published in the journal Nature.


Personalized cancer vaccines

Therapeutic cancer vaccines were first developed 100 years ago and have remained broadly ineffective to date. Before tangible results can be achieved, two major obstacles must be overcome. Firstly, since tumor mutations are unique to each patient, cancer cell antigens must be targeted extremely precisely, which is very hard to achieve. Secondly, a safe system is needed to deliver the vaccine to the right location and achieve a strong and specific immune response.

Li Tang’s team at EPFL’s School of Engineering in Switzerland is coming up with a solution to the delivery problem. The researchers have used a polymerization technique called polycondensation to develop a prototype vaccine that can travel automatically to the desired location and activate immune cells there. The patented technique has been successfully tested in mice and is the topic of a paper appearing in ACS Central Science. Li Tang has also co-founded a startup called PepGene, with partners that are working on an algorithm for quickly and accurately predicting mutated tumor antigens. Together, the two techniques should result in a new and better cancer vaccine in the next several years.

Helping the body to defend itself

Most vaccines – against measles and tetanus for example – are preventive. Healthy individuals are inoculated with weakened or inactivated parts of a virus, which prompt their immune systems to produce antibodies. This prepares the body to defend itself against future infection.

However, the aim of a therapeutic cancer vaccine is not to prevent the disease, but to help the body defend itself against a disease that is already present. “There are various sorts of immunotherapies other than vaccines, but some patients don’t respond well to them. The vaccine could be combined with those immunotherapies to obtain the best possible immune response,” explains Li Tang. Another advantage is that vaccines should reduce the risk of relapse.

Delivering a cancer vaccine to the immune system involves various stages. First, the patient is inoculated with the vaccine subcutaneously. The vaccine will thus travel to the lymph nodes, where there are lots of immune cells. Once there, the vaccine is expected to penetrate dendritic cells, which act as a kind of alert mechanism. If the vaccine stimulates them correctly, the dendritic cells present specific antigens to cancer-fighting T-cells, a process that activates and trains the T-cells to attack them.

The procedure appears simple, but is extremely hard to put into practice. Because they are very small, the components of a vaccine tend to disperse or be absorbed in the blood stream before reaching the lymph nodes.

To overcome that obstacle, Li Tang has developed a system that chemically binds the vaccine’s parts together to form a larger entity. The new vaccine, named Polycondensate Neoepitope (PNE), consists of neoantigens (mutated antigens specific to the tumor to be attacked) and an adjuvant. When combined within a solvent, the components naturally bind together, forming an entity that is too large to be absorbed by blood vessels and that travels naturally to the lymph nodes.


How To Offer Commercially Attractive Carbon-Capturing

Chemical engineers from the Ecole Polytechnique Fédérale de Lausanne  (EPFL ) in Switzerland have designed an easy method to achieve commercially attractive carbon-capturing with metal-organic frameworksMetal-organic frameworks (MOFs) are versatile compounds hosting nano-sized pores in their crystal structure. Because of their nanopores, MOFs are now used in a wide range of applications, including separating petrochemicalsmimicking DNA, and removing heavy metals, fluoride anions, hydrogen, and even gold from waterGas separation in particular is of great interest to a number of industries, such as biogas production, enriching air in metal working, purifying natural gas, and recovering hydrogen from ammonia plants and oil refineries.

The flexible ‘lattice’ structure of metal-organic frameworks soaks up gas molecules that are even larger than its pore window making it difficult to carry out efficient membrane-based separation,” says Kumar Varoon Agrawal, who holds the GAZNAT Chair for Advanced Separations at EPFL Valais Wallis.

Now, scientists from Agrawal’s lab have greatly improved the gas separation by making the MOF lattice structure rigid. They did this by using a novel “post-synthetic rapid heat treatment” method, which basically involved baking a popular MOF called ZIF-8 (zeolitic imidazolate framework 8) at 360°C for a few seconds. The method drastically improved ZIF-8’s gas-separation performance – specifically in ‘carbon capture’, a process that captures carbon dioxide emissions produced from the use of fossil fuels, preventing it from entering the atmosphere. “For the first time, we have achieved commercially attractive dioxide sieving performance a MOF membrane,” says Agrawal.


Optical Circuits Up To 100 Times Faster Than Electronic Circuits

Optical circuits are set to revolutionize the performance of many devices. Not only are they 10 to 100 times faster than electronic circuits, but they also consume a lot less power. Within these circuits, light waves are controlled by extremely thin surfaces called metasurfaces that concentrate the waves and guide them as needed. The metasurfaces contain regularly spaced nanoparticles that can modulate electromagnetic waves over sub-micrometer wavelength scales.

Metasurfaces could enable engineers to make flexible and ultra-thin optics for a host of applications, ranging from flexible tablet computers to solar panels with enhanced light-absorption characteristics. They could also be used to create flexible sensors for direct placement on a patient’s skin, for example, in order to measure things like pulse and blood pressure or to detect specific chemical compounds.

The catch is that creating metasurfaces using the conventional method, lithography, is a fastidious process that takes several hours and must be done in a cleanroom. But EPFL engineers from the Laboratory of Photonic Materials and Fiber Devices (FIMAP) in Switzerland have now developed a simple method for making them in just a few minutes at low temperatures—or sometimes even at room temperature—with no need for a cleanroom. The EPFL‘s School of Engineering method produces dielectric glass metasurfaces that can be either rigid or flexible. The results of their research appear in Nature Nanotechnology.

The new method employs a natural process already used in : dewetting. This occurs when a thin film of material is deposited on a substrate and then heated. The heat causes the film to retract and break apart into tiny nanoparticles.

Dewetting is seen as a problem in manufacturing—but we decided to use it to our advantage,” says Fabien Sorin, the study’s lead author and the head of FIMAP.

With their method, the engineers were able to create dielectric glass metasurfaces, rather than metallic metasurfaces, for the first time. The advantage of dielectric metasurfaces is that they absorb very little light and have a high refractive index, making it possible to modulate the light that propagates through them.