Meghan Huber wearing the hip exoskeleton with Mark Price and Banu Abdikadirova (credit: Derrick Zellmann). Credit: Derrick Zellmann

More than 80% of stroke survivors experience walking difficulty, significantly impacting their daily lives, independence, and overall quality of life. Now, new research from the University of Massachusetts Amherst pushes forward the bounds of stroke recovery with a unique robotic hip exoskeleton designed as a training tool to improve walking function.

This invites the possibility of new therapies that are more accessible and easier to translate from practice to daily life compared to current rehabilitation methods.

Following a stroke, people often experience walking asymmetry, where one step is shorter than the other. The study, published in IEEE Transactions on Neural Systems and Rehabilitation Engineering, reveals that the robotic hip exoskeleton has the potential to effectively train individuals to modify their walking asymmetry, presenting a promising avenue for stroke rehabilitation.

The approach employed by the robotic exoskeleton is inspired by split-belt treadmills, which are specialized machines with two side-by-side belts moving at different speeds. Prior research has shown that repeated training on a split-belt treadmill can reduce walking asymmetry in stroke patients.

Wouter Hoogkamer, assistant professor of kinesiology and author of the paper, has spent the last decade studying split-belt treadmills. “Split-belt treadmill training is designed to exaggerate a stroke patient’s walking asymmetry by running the belts under each foot at different speeds. Over time, the nervous system adapts, such that when the belts are set to the same speed, they walk more symmetrically.”

Unfortunately, there are limits to the benefits gained from treadmill-based training methods. “What is learned on a treadmill does not completely transfer to overground contexts,” says Banu Abdikadirova, mechanical and industrial engineering doctoral candidate and lead study author. “This is because walking on a treadmill is not exactly the same as walking overground.”

“The ultimate goal of gait rehabilitation is not to improve walking on a treadmill—it is to improve locomotor function overground,” says Meghan Huber, assistant professor of mechanical and industrial engineering and senior author on the paper. “With this in mind, our focus is to develop methods of gait rehabilitation that translate to functional improvements in real-world contexts.”

This proof-of-concept study showed that applying resistive forces about one hip joint and assistive forces about the other with their exoskeleton mimicked the effects of split-belt treadmill training in neurologically intact individuals.

Now that the research team has proven that the exoskeleton can alter gait asymmetry, they are eager to move their research into overground contexts that are more akin to the real world.

“Because our exoskeleton is portable, it can be used during overground walking,” says Mark Price, a postdoctoral researcher in mechanical and industrial engineering and kinesiology and author on the paper. “We can build upon the successes of split-belt treadmill training with this device to enhance the accessibility of gait training and enhance the transfer of training benefits into everyday walking contexts.”

The researchers also plan to expand their work by measuring the neural changes caused by walking with the exoskeleton and testing this new method on stroke survivors.

“A portable exoskeleton offers numerous clinical benefits,” says Abdikadirova. “Such a device can be seamlessly integrated into the daily lives of chronic stroke survivors, offering an accessible way to increase training time, which is critical for improving walking. It can also be used during early intervention in hospitals for improved functional outcomes.”

The robotic hip exoskeleton is just one of the innovative devices designed to study and enhance gait function developed by the collaborative team of undergraduate students, graduate students, and postdoctoral researchers from the Human Robot Systems Lab, led by Huber, and the Integrative Locomotion Lab, led by Hoogkamer.

“It is inspiring to witness the innovations that emerge when individuals from diverse backgrounds unite under a shared mission,” says Huber. “Only through this type of cross-disciplinary research can we engineer technologies that can have a meaningful impact on people’s lives.”

This image shows a flattened (Mercator) projection of the Huygens probe’s view of Saturn’s moon Titan from 10 kilometers altitude. The images that make up this view were taken on Jan. 14, 2005, with the descent imager/spectral radiometer onboard the European Space Agency’s Huygens probe. The Huygens probe was delivered to Titan by the Cassini spacecraft, managed by NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Credit: ESA/NASA/JPL/University of Arizona photo

A study led by Western astrobiologist Catherine Neish shows the subsurface ocean of Titan—the largest moon of Saturn—is most likely a non-habitable environment, meaning any hope of finding life in the icy world is dead in the water.

This discovery means it is far less likely that space scientists and astronauts will ever find life in the outer solar system, home to the four ‘giant’ planets: Jupiter, Saturn, Uranus and Neptune.

“Unfortunately, we will now need to be a little less optimistic when searching for extraterrestrial lifeforms within our own solar system,” said Neish, an Earth sciences professor. “The scientific community has been very excited about finding life in the icy worlds of the outer solar system, and this finding suggests that it may be less likely than we previously assumed.”

The identification of life in the outer solar system is a significant area of interest for planetary scientists, astronomers and government space agencies like NASA, largely because many icy moons of the giant planets are thought to have large subsurface oceans of liquid water. Titan, for example, is thought to have an ocean beneath its icy surface that is more than 12 times the volume of Earth’s oceans.

“Life as we know it here on Earth needs water as a solvent, so planets and moons with lots of water are of interest when looking for extraterrestrial life,” said Neish, a member of Western’s Institute for Earth and Space Exploration.

In the study, published in the journal Astrobiology, Neish and her collaborators attempted to quantify the amount of organic molecules that could be transferred from Titan’s organic-rich surface to its subsurface ocean, using data from impact cratering.

Comets impacting Titan throughout its history have melted the surface of the icy moon, creating pools of liquid water that have mixed with the surface organics. The resulting melt is denser than its icy crust, so the heavier water sinks through the ice, possibly all the way to Titan’s subsurface ocean.

Using the assumed rates of impacts on Titan’s surface, Neish and her collaborators determined how many comets of different sizes would strike Titan each year over its history. This allowed the researchers to predict the flow rate of water carrying organics that travel from Titan’s surface to its interior.

Neish and the team found the weight of organics transferred in this way is quite small, no more than 7,500 kg/year of glycine—the simplest amino acid, which makes up proteins in life. This is approximately the same mass as a male African elephant. (All biomolecules, like glycine, use carbon—an element—as the backbone of their molecular structure.)

“One elephant per year of glycine into an ocean 12 times the volume of Earth’s oceans is not sufficient to sustain life,” said Neish. “In the past, people often assumed that water equals life, but they neglected the fact that life needs other elements, in particular carbon.”

Other icy worlds (like Jupiter’s moons Europa and Ganymede and Saturn’s moon Enceladus) have almost no carbon on their surfaces, and it is unclear how much could be sourced from their interiors. Titan is the most organic-rich icy moon in the solar system, so if its subsurface ocean is not habitable, it does not bode well for the habitability of other known icy worlds.

“This work shows that it is very hard to transfer the carbon on Titan’s surface to its subsurface ocean—basically, it’s hard to have both the water and carbon needed for life in the same place,” said Neish.

An artist’s rendering shows a Dragonfly quadcopter landing on the surface of Saturn’s moon Titan, unfolding its rotors and lifting off again to survey the landscape and atmosphere. Credit: Steve Gribben/Johns Hopkins

Flight of the Dragonfly

Despite the discovery, there is still much more to learn about Titan, and for Neish, the big question is, what is it made of?

Neish is a co-investigator on the NASA Dragonfly project, a planned 2028 spacecraft mission to send a robotic rotorcraft (drone) to the surface of Titan to study its prebiotic chemistry, or how organic compounds formed and self-organized for the origin of life on Earth and beyond.

“It is nearly impossible to determine the composition of Titan’s organic-rich surface by viewing it with a telescope through its organic-rich atmosphere,” said Neish. “We need to land there and sample the surface to determine its composition.”

To date, only the Cassini–Huygens international space mission in 2005 has successfully landed a robotic probe on Titan to analyze samples. It remains the first spacecraft to land on Titan and the farthest landing from Earth a spacecraft has ever made.

“Even if the subsurface ocean isn’t habitable, we can learn a lot about prebiotic chemistry on Titan, and Earth, by studying the reactions on Titan’s surface,” said Neish. “We’d really like to know if interesting reactions are occurring there, especially where the organic molecules mix with liquid water generated in impacts.”

When Neish started her latest study, she was worried it would negatively impact the Dragonfly mission, but it has actually led to even more questions.

“If all the melt produced by impacts sinks into the ice crust, we wouldn’t have samples near the surface where water and organics have mixed. These are regions where Dragonfly could search for the products of those prebiotic reactions, teaching us about how life may arise on different planets,” said Neish.

“The results from this study are even more pessimistic than I realized with regards to the habitability of Titan’s surface ocean, but it also means that more interesting prebiotic environments exist near Titan’s surface, where we can sample them with the instruments on Dragonfly.”

A shallow coral reef on Australia’s Great Barrier Reef. Credit: Chris Roelfsema

University of Queensland-led research has shown there is more coral reef area across the globe than previously thought, with detailed satellite mapping helping to conserve these vital ecosystems.

Dr. Mitchell Lyons from UQ’s School of the Environment, working as part of the Allen Coral Atlas project, said scientists have now identified 348,000 square kilometers of shallow coral reefs, up to 20–30 meters deep. The research paper is published in Cell Reports Sustainability.

“This revises up our previous estimate of shallow reefs in the world’s oceans,” Dr. Lyons said.

“Importantly, the high-resolution, up-to-date mapping satellite technology also allows us to see what these habitats are made from.

“We’ve found 80,000 square kilometers of reef have a hard bottom, where coral tends to grow, as opposed to soft bottom like sand, rubble or seagrass.

“This data will allow scientists, conservationists, and policymakers to better understand and manage reef systems.”

More than 1.5 million samples and 100 trillion pixels from the Sentinel-2 and Planet Dove CubeSat satellites were used to capture fine-scale detail on a high-resolution global map.

“This is the first accurate depiction of the distribution and composition of the world’s coral reefs, with clear and consistent terminology,” Dr. Lyons said.

“It’s more than just a map—it’s a tool for positive change for reefs and coastal and marine environments at large.”

A diver on a shallow coral reef on Australia’s Great Barrier Reef. Credit: Chris Roelfsema

UQ’s Associate Professor Chris Roelfsema said the reef mapping project, a collaboration with more than 480 contributors, is already being used in coral reef conservation around the world.

“The maps and associated data are publicly accessible through the Allen Coral Atlas and Google Earth Engine, reaching a global audience,” Dr. Roelfsema said.

“They’re being used to inform projects in Australia, Indonesia, the Timor and Arafura Seas, Fiji, Solomon Islands, Tonga, Vanuatu, Panama, Belize, Bangladesh, India, Maldives, Sri Lanka, Kenya and western Micronesia.

“The details provided by these maps empower scientists, policymakers and local communities to make informed decisions for the preservation of our coral reefs.”

The Allen Coral Atlas was conceived by the late Paul Allen’s Vulcan Inc. and managed by Arizona State University along with partners from Planet, the Coral Reef Alliance and The University of Queensland.

Tridentinosaurus antiquus was discovered in the Italian alps in 1931 and was thought to be an important specimen for understanding early reptile evolution—but has now been found to be, in part a forgery. Its body outline, appearing dark against the surrounding rock, was initially interpreted as preserved soft tissues but is now known to be painted. Credit: Dr. Valentina Rossi

A 280-million-year-old fossil that has baffled researchers for decades has been shown to be—in part—a forgery, following new examination of the remnants.

The discovery has led the team, headed by Dr. Valentina Rossi of University College Cork, Ireland (UCC) to urge caution in how the fossil is used in future research.

Tridentinosaurus antiquus was discovered in the Italian Alps in 1931 and was thought to be an important specimen for understanding early reptile evolution. Its body outline, appearing dark against the surrounding rock, was initially interpreted as preserved soft tissues. This led to its classification as a member of the reptile group Protorosauria.

However, this new research, published in the journal Palaeontology, reveals that the fossil renowned for its remarkable preservation is mostly just black paint on a carved lizard-shaped rock surface.

The purported fossilized skin had been celebrated in articles and books but never studied in detail. The somewhat strange preservation of the fossil had left many experts uncertain about which group of reptiles this strange lizard-like animal belonged to, and more generally its geological history.

Dr. Valentina Rossi with an image of Tridentinosaurus antiquus. The fossil, discovered in the Italian alps in 1931, was thought to be an important specimen for understanding early reptile evolution—but has now been found to be, in part a forgery. Its body outline, appearing dark against the surrounding rock, was initially interpreted as preserved soft tissues but is now known to be paint. Credit: Zixiao Yang

Dr. Rossi, of UCC’s School of Biological, Earth and Environmental Sciences, said, “Fossil soft tissues are rare, but when found in a fossil they can reveal important biological information, for instance, the external coloration, internal anatomy and physiology. The answer to all our questions was right in front of us; we had to study this fossil specimen in details to reveal its secrets—even those that perhaps we did not want to know.”

The microscopic analysis showed that the texture and composition of the material did not match that of genuine fossilized soft tissues.

Preliminary investigation using UV photography revealed that the entirety of the specimen was treated with some sort of coating material. Coating fossils with varnishes and/or lacquers was the norm in the past and sometimes is still necessary to preserve a fossil specimen in museum cabinets and exhibits. The team was hoping that beneath the coating layer, the original soft tissues were still in good condition to extract meaningful paleobiological information.

The findings indicate that the body outline of Tridentinosaurus antiquus was artificially created, likely to enhance the appearance of the fossil. This deception misled previous researchers, and now caution is being urged when using this specimen in future studies.

The team behind this research includes contributors based in Italy at the University of Padua, Museum of Nature South Tyrol, and the Museo delle Scienze in Trento.

Co-author Prof Evelyn Kustatscher, coordinator of the project “Living with the supervolcano,” said, “The peculiar preservation of Tridentinosaurus had puzzled experts for decades. Now, it all makes sense. What it was described as carbonized skin is just paint.”

However, not all is lost, and the fossil is not a complete fake. The bones of the hindlimbs, in particular, the femurs seem genuine, although poorly preserved. Moreover, the new analyses have shown the presence of tiny bony scales called osteoderms—like the scales of crocodiles—on what perhaps was the back of the animal.

This study is an example of how modern analytical paleontology and rigorous scientific methods can resolve an almost century-old paleontological enigma.