Science & Technology

Physicists have created a new 'time crystal'—it won't power a time machine but could have many other uses

Daniel William Strain — Fri, 05 Sep 2025 14:22:52 +0000

Physicists have created a new 'time crystal'—it won't power a time machine but could have many other uses Daniel William… Fri, 09/05/2025 - 08:22

Daniel Strain

Imagine a clock that doesn’t have electricity, but its hands and gears spin on their own for all eternity.

In a new study, physicists at 91ɫ�� have used liquid crystals, the same materials that are in your phone display, to create such a clock—or, at least, as close as humans can get to that idea. The team’s advancement is a new example of a “time crystal.” That’s the name for a curious phase of matter in which the pieces, such as atoms or other particles, exist in constant motion.

A time crystal as seen under a microscope. (Credit: Zhao & Smalyukh, 2025, Nature Materials; CC image: https://creativecommons.org/licenses/by-nc-nd/4.0/)

The researchers aren’t the first to make a time crystal, but their creation is the first that humans can actually see, which could open a host of technological applications.

“They can be observed directly under a microscope and even, under special conditions, by the naked eye,” said Hanqing Zhao, lead author of the study and a graduate student in the Department of Physics at 91ɫ��.

He and Ivan Smalyukh, professor of physics and fellow with the Renewable and Sustainable Energy Institute (RASEI), published their findings Sept. 4 in the journal "Nature Materials."

In the study, the researchers designed glass cells filled with liquid crystals—in this case, rod-shaped molecules that behave a little like a solid and a little like a liquid. Under special circumstances, if you shine a light on them, the liquid crystals will begin to swirl and move, following patterns that repeat over time.

Under a microscope, these liquid crystal samples resemble psychedelic tiger stripes, and they can keep moving for hours—similar to that eternally spinning clock.

“Everything is born out of nothing,” Smalyukh said. “All you do is shine a light, and this whole world of time crystals emerges.”

Zhao and Smalyukh are members of the Colorado satellite of the International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2) with headquarters at Hiroshima University in Japan, an international institute with missions to create artificial forms of matter and contribute to sustainability.

Video of a time crystal in motion. (Credit: Smalyukh Lab)

A computer simulation reveals the inner workings of a time crystal. A beam of light, blue arrow, causes dye molecules, red rods, to change their orientation, driving motion in liquid crystals below. (Credit: Smalyukh Lab)

By stacking several time crystals on top of each other, physicists can create more complex patterns, including what they refer to as a "time barcode." (Credit: Smalyukh Lab)

Crystals in space and time

Time crystals may sound like something out of science fiction, but they take their inspiration from naturally occurring crystals, such as diamonds or table salt.

Nobel laureate Frank Wilczek first proposed the idea of time crystals in 2012. You can think of traditional crystals as “space crystals.” The carbon atoms that make up a diamond, for example, form a lattice pattern in space that is very hard to break apart. Wilczek wondered if it would be possible to build a crystal that was similarly well organized, except in time rather than space. Even in their resting state, the atoms in such a state wouldn’t form a lattice pattern, but would move or transform in a never-ending cycle—like a GIF that loops forever.

Wilczek’s original concept proved impossible to make, but, in the years since, scientists have created phases of matter that get reasonably close.

In 2021, for example, physicists used Google’s Sycamore quantum computer to create a special network of atoms. When the team gave those atoms a flick with a laser beam, they underwent fluctuations that repeated multiple times.

Dancing crystals

In the new study, Zhao and Smalyukh set out to see if they could achieve a similar feat with liquid crystals.

Smalyukh explained that if you squeeze on these molecules in the right way, they will bunch together so tightly that they form kinks. Remarkably, these kinks move around and can even, under certain conditions, behave like atoms.

“You have these twists, and you can’t easily remove them,” Smalyukh said. “They behave like particles and start interacting with each other.”

In the current study, Smalyukh and Zhao sandwiched a solution of liquid crystals in between two pieces of glass that were coated with dye molecules. On their own, these samples mostly sat still. But when the group hit them with a certain kind of light, the dye molecules changed their orientation and squeezed the liquid crystals. In the process, thousands of new kinks suddenly formed.

Those kinks also began interacting with each other following an incredibly complex series of steps. Think of a room filled with dancers in a Jane Austen novel. Pairs break apart, spin around the room, come back together, and do it all over again. The patterns in time were also unusually hard to break—the researchers could raise or lower the temperature of their samples without disrupting the movement of the liquid crystals.

“That’s the beauty of this time crystal,” Smalyukh said. “You just create some conditions that aren’t that special. You shine a light, and the whole thing happens.”

Zhao and Smalyukh say that such time crystals could have several uses. Governments could, for example, add these materials to bills to make them harder to counterfeit—if you want to know if that $100 bill is genuine, just shine a light on the “time watermark” and watch the pattern that appears. By stacking several different time crystals, the group can create even more complicated patterns, which could potentially allow engineers to store vast amounts of digital data.

“We don’t want to put a limit on the applications right now,” Smalyukh said. “I think there are opportunities to push this technology in all sorts of directions.”

A team at 91ɫ�� has made a curious state of matter in which particles move constantly—like a clock with hands and gears that spin forever, even without electricity to keep them going.

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The stripes in a time crystal seen under the microscope. (Credit: Zhao & Smalyukh, 2025, Nature Materials; CC image: https://creativecommons.org/licenses/by-nc-nd/4.0/)

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The stripes in a time crystal seen under a microscope. (Credit: Zhao & Smalyukh, 2025, Nature Materials; CC image: https://creativecommons.org/licenses/by-nc-nd/4.0/)

New single-dose, temperature-stable rabies vaccines could expand global access

Amber Elise Carlson — Thu, 04 Sep 2025 19:46:39 +0000

New single-dose, temperature-stable rabies vaccines could expand global access Amber Elise Carlson Thu, 09/04/2025 - 13:46

Amber Carlson

A pair of gloved hands holds a syringe and a vial with a vaccine solution. (Credit: Adobe Stock)

Roughly 60,000 people worldwide die every year from rabies, a dreaded virus that attacks the nervous system and can trigger aggression, seizures, paralysis and coma.

In industrialized countries, infections and deaths in humans are rare, thanks to vaccines widely given to pets and people for prevention and available as a life-saving treatment once someone has been exposed. But in developing countries, including rural parts of Asia and Africa, rabies remains a major threat.

Now, 91ɫ�� researchers have discovered a new way to make human rabies vaccines that could greatly expand access to immunization across the globe. The new method, outlined in an August 2025 paper in the Journal of Pharmaceutical Sciences, creates shots that are temperature-stable—meaning they don’t need to be stored at cold temperatures like traditional rabies vaccines.

These innovative shots also combine multiple timed-release doses into a single injection, potentially reducing the number of health care visits each person needs and helping to break down barriers to care. The same process could also be used to create other vaccines, including those for human papillomavirus (HPV) and human immunodeficiency virus (HIV).

“We think the implications of this are huge,” said Ted Randolph, a professor in 91ɫ��’s Department of Chemical and Biological Engineering and the lead author of the new study. “We’re really excited about it.”

Challenges of current rabies vaccines

Vaccines can work in a variety of ways. Some, like vaccines against flu or rabies, expose the body to weakened, inactivated or killed viruses. This teaches the body to recognize proteins found on their surfaces and create antibodies that fight future infections by binding to those proteins. Others, like protein-based vaccines for Covid, contain select proteins from the target pathogen that can trigger a similar immune response.

From left, Ted Randolph and colleague Robert Garcea pose for a photo. (Credit: Glenn Asakawa)

All currently marketed vaccines need to be kept refrigerated or frozen—sometimes at temperatures as low as minus 76 degrees Fahrenheit—because the proteins in them start to degrade at warmer temperatures.

Like milk that sat out on the counter too long, a vaccine solution can curdle as its proteins break down and clump together. At that point, the shots are no longer effective. Cooling them slows down the protein degradation process, said Randolph.

“The proteins basically want to make cheese,” he said. “You have to keep them from making cheese for long enough that you can manufacture the vaccines, get them to pharmacies and hospitals, and get them to patients.”

This makes it difficult, if not impossible, to administer traditional rabies vaccines in regions that lack electricity or don’t have the specialized cold storage equipment needed. In areas with electricity but poor infrastructure, a single power outage can wipe out vaccine supplies for entire communities.

The rabies vaccine also requires between three and five doses at timed intervals, depending on the patient. People in developing countries tend to visit doctors less often and have a harder time accessing medical care, so they are less likely to get all the needed doses.

‘Sapphire-coated Jolly Ranchers’

Even at warm temperatures, the shots developed by Randolph’s team don’t degrade.

To make them, the team sprays sugar solutions containing inactivated rabies viruses and other vaccine components through nozzles that make a fine mist, which dries to form a powder of microparticles. These microparticles have a glassy texture similar to that of a hard candy. The rabies virus proteins are immobilized and preserved in the candy coating, like ancient insect fossils trapped in amber.

Next, the team coats the candied particles with a layer of aluminum oxide (sapphire) of precisely controlled nanoscopic thickness using a process called atomic layer deposition pioneered by Alan Weimer and Steven George, professors in engineering and chemistry at 91ɫ��.

Because sapphire dissolves very slowly once injected into a patient, the nanoscopic sapphire layer protects the sugar-coated vaccine particles for days to weeks, depending on the thickness of the sapphire layer applied on the microparticles. When the sapphire starts to break down, the sugar layer dissolves, and the vaccine particles are released into the body one dose at a time.

A microscopic image shows vaccine particles with a sapphire coating. These particles are fractured to show the coating. (Credit: Ted Randolph)

“We're basically making sapphire-coated Jolly Ranchers,” Randolph said.

These vaccines are stable at high temperatures, can be stored in a dry powder form and delivered in bulk to parts of the world that lack cold-storage capacity.

“You can now take these vaccines to places without refrigeration, and even to places that get hot,” Randolph said. “So transportation through rural India or wherever you're going is no longer a problem.”

It’s too soon to know how effective these vaccines are in humans. Currently, they’re being tested in animals, and human clinical trials are at least a couple of years away. But the results from early testing have been promising.

In mice, the researchers found that even single injections of the spray-dried, sapphire-coated vaccine powders sparked stronger immune responses than multiple doses of traditional liquid rabies vaccines. The immune responses did not weaken after storing the vaccines for three months at temperatures up to 104 degrees Fahrenheit.

Randolph and his colleague Robert Garcea, professor emeritus in 91ɫ��’s Department of Molecular, Cellular and Developmental Biology, have formed a startup company called VitriVax to bring the technology—decades in the making—to market.

“It's been 25 years of lots of talented grad students adding little bits and pieces to the puzzle. It’s the kind of thing that does require long-term dedication, work and funding,” Randolph said.

Beyond the story

Our bioscience impact by the numbers:

Top 7% university for National Science Foundation research funding
No. 30 global university system granted U.S. patents
89-plus biotech startups with roots at 91ɫ�� in past 20 years

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91ɫ�� engineers have developed a new method for making vaccines that combines multiple, timed-release doses into a single injection that doesn't require refrigeration.

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Inside the Colorado Quantum Incubator with Quantum Rings

Megan Maneval — Tue, 02 Sep 2025 12:52:28 +0000

Inside the Colorado Quantum Incubator with Quantum Rings Megan Maneval Tue, 09/02/2025 - 06:52

The Colorado Quantum Incubator—a 91ɫ��-led hub for advancing quantum research, innovation and community engagement—is ramping up operations as it welcomes its first companies, including inaugural tenant Quantum Rings, a rising leader in quantum software simulation.

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New AI tool identifies 1,000 'questionable' scientific journals

Daniel William Strain — Thu, 28 Aug 2025 19:40:06 +0000

New AI tool identifies 1,000 'questionable' scientific journals Daniel William… Thu, 08/28/2025 - 13:40

Daniel Strain

A team of computer scientists led by the 91ɫ�� has developed a new artificial intelligence platform that automatically seeks out “questionable” scientific journals.

The study, published Aug. 27 in the journal “Science Advances,” tackles an alarming trend in the world of research.

Daniel Acuña, lead author of the study and associate professor in the Department of Computer Science, gets a reminder of that several times a week in his email inbox: These spam messages come from people who purport to be editors at scientific journals, usually ones Acuña has never heard of, and offer to publish his papers—for a hefty fee.

Such publications are sometimes referred to as “predatory” journals. They target scientists, convincing them to pay hundreds or even thousands of dollars to publish their research without proper vetting.

Daniel Acuña

“There has been a growing effort among scientists and organizations to vet these journals,” Acuña said. “But it’s like whack-a-mole. You catch one, and then another appears, usually from the same company. They just create a new website and come up with a new name.”

His group’s new AI tool automatically screens scientific journals, evaluating their websites and other online data for certain criteria: Do the journals have an editorial board featuring established researchers? Do their websites contain a lot of grammatical errors?

Acuña emphasizes that the tool isn’t perfect. Ultimately, he thinks human experts, not machines, should make the final call on whether a journal is reputable.

But in an era when prominent figures are questioning the legitimacy of science, stopping the spread of questionable publications has become more important than ever before, he said.

“In science, you don’t start from scratch. You build on top of the research of others,” Acuña said. “So if the foundation of that tower crumbles, then the entire thing collapses.”

The shake down

When scientists submit a new study to a reputable publication, that study usually undergoes a practice called peer review. Outside experts read the study and evaluate it for quality—or, at least, that’s the goal.

A growing number of companies have sought to circumvent that process to turn a profit. In 2009, Jeffrey Beall, a librarian at CU Denver, coined the phrase “predatory” journals to describe these publications.

Often, they target researchers outside of the United States and Europe, such as in China, India and Iran—countries where scientific institutions may be young, and the pressure and incentives for researchers to publish are high.

“They will say, ‘If you pay $500 or $1,000, we will review your paper,’” Acuña said. “In reality, they don’t provide any service. They just take the PDF and post it on their website.”

A few different groups have sought to curb the practice. Among them is a nonprofit organization called the Directory of Open Access Journals (DOAJ). Since 2003, volunteers at the DOAJ have flagged thousands of journals as suspicious based on six criteria. (Reputable publications, for example, tend to include a detailed description of their peer review policies on their websites.)

But keeping pace with the spread of those publications has been daunting for humans.

To speed up the process, Acuña and his colleagues turned to AI. The team trained its system using the DOAJ’s data, then asked the AI to sift through a list of nearly 15,200 open-access journals on the internet.

Among those journals, the AI initially flagged more than 1,400 as potentially problematic.

Acuña and his colleagues asked human experts to review a subset of the suspicious journals. The AI made mistakes, according to the humans, flagging an estimated 350 publications as questionable when they were likely legitimate. That still left more than 1,000 journals that the researchers identified as questionable.

“I think this should be used as a helper to prescreen large numbers of journals,” he said. “But human professionals should do the final analysis.”

A firewall for science

Acuña added that the researchers didn't want their system to be a "black box" like some other AI platforms.

“With ChatGPT, for example, you often don’t understand why it’s suggesting something,” Acuña said. “We tried to make ours as interpretable as possible.”

The team discovered, for example, that questionable journals published an unusually high number of articles. They also included authors with a larger number of affiliations than more legitimate journals, and authors who cited their own research, rather than the research of other scientists, to an unusually high level.

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Our research impact by the numbers:

45 U.S. patents issued for CU inventions through Venture Partners in 2023–24
35 startups launched based on university innovations in 2023–24
$1.2 billion raised by companies built on 91ɫ�� innovations in 2022–24

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The new AI system isn’t publicly accessible, but the researchers hope to make it available to universities and publishing companies soon. Acuña sees the tool as one way that researchers can protect their fields from bad data—what he calls a “firewall for science.”

“As a computer scientist, I often give the example of when a new smartphone comes out,” he said. “We know the phone's software will have flaws, and we expect bug fixes to come in the future. We should probably do the same with science.”

Co-authors on the study included Han Zhuang at the Eastern Institute of Technology in China and Lizheng Liang at Syracuse University in the United States.

Questionable scientific journals, or those that publish studies without proper vetting for a profit, are growing around the world. A new AI system automatically seeks them out.

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Robot regret: New research helps robots make safer decisions around humans

Amber Elise Carlson — Mon, 25 Aug 2025 15:59:28 +0000

Robot regret: New research helps robots make safer decisions around humans Amber Elise Carlson Mon, 08/25/2025 - 09:59

Amber Carlson , Nicholas Goda , Jesse Petersen

Imagine for a moment that you’re in an auto factory. A robot and a human are working next to each other on the production line. The robot is busy rapidly assembling car doors while the human runs quality control, inspecting the doors for damage and making sure they come together as they should.

Robots and humans can make formidable teams in manufacturing, health care and numerous other industries. While the robot might be quicker and more effective at monotonous, repetitive tasks like assembling large auto parts, the person can excel at certain tasks that are more complex or require more dexterity.

But there can be a dark side to these robot-human interactions. People are prone to making mistakes and acting unpredictably, which can create unexpected situations that robots aren’t prepared to handle. The results can be tragic.

New and emerging research could change the way robots handle the uncertainty that comes hand-in-hand with human interactions. Morteza Lahijanian, an associate professor in 91ɫ��’s Ann and H.J. Smead Department of Aerospace Engineering Sciences, develops processes that let robots make safer decisions around humans while still trying to complete their tasks efficiently.

From left, engineering professor Morteza Lahijanian and graduate student Karan Muvvala watch as a robotic arm completes a task using wooden blocks. (Credit: Casey Cass)

In a new study presented at the International Joint Conference on Artificial Intelligence in August 2025, Lahijanian and graduate students Karan Muvvala and Qi Heng Ho devised new algorithms that help robots create the best possible outcomes from their actions in situations that carry some uncertainty and risk.

“How do we go from very structured environments where there is no human, where the robots are doing everything by themselves, to unstructured environments where there are a lot of uncertainties and other agents?” Lahijanian asked.

“If you’re a robot, you have to be able to interact with others. You have to put yourself out there and take a risk and see what happens. But how do you make that decision, and how much risk do you want to tolerate?”

Similar to humans, robots have mental models that they use to make decisions. When working with a human, a robot will try to predict the person’s actions and respond accordingly. The robot is optimized for completing a task—assembling an auto part, for example—but ideally, it will also take other factors into consideration.

In the new study, the research team drew upon game theory, a mathematical concept that originated in economics, to develop the new algorithms for robots. Game theory analyzes how companies, governments and individuals make decisions in a system where other “players” are also making choices that affect the ultimate outcome.

In robotics, game theory conceptualizes a robot as being one of numerous players in a game that it’s trying to win. For a robot, “winning” is completing a task successfully—but winning is never guaranteed when there’s a human in the mix, and keeping the human safe is also a top priority.

So instead of trying to guarantee a robot will always win, the researchers proposed the concept of a robot finding an “admissible strategy.” Using such a strategy, a robot will accomplish as much of its task as possible while also minimizing any harm, including to a human.

“In choosing a strategy, you don't want the robot to seem very adversarial,” said Lahijanian. “In order to give that softness to the robot, we look at the notion of regret. Is the robot going to regret its action in the future? And in optimizing for the best action at the moment, you try to take an action that you won't regret.”

Let’s go back to the auto factory where the robot and human are working side-by-side. If the person makes mistakes or is not cooperative, using the researchers’ algorithms, a robot could take matters into its own hands. If the person is making mistakes, the robot will try to fix these without endangering the person. But if that doesn’t work, the robot could, for example, pick up what it’s working on and take it to a safer area to finish its task.

Karan Muvvala watches the robotic arm pick up a blue block. (Credit: Casey Cass)

Much like a chess champion who thinks several turns ahead about an opponent’s possible moves, a robot will try to anticipate what a person will do and stay several steps ahead of them, Lahijanian said.

But the goal is not to attempt the impossible and perfectly predict a person’s actions. Instead, the goal is to create robots that put people’s safety first.

“If you want to have collaboration between a human and a robot, the robot has to adjust itself to the human. We don't want humans to adjust themselves to the robot,” he said. “You can have a human who is a novice and doesn't know what they're doing, or you can have a human who is an expert. But as a robot, you don't know which kind of human you're going to get. So you need to have a strategy for all possible cases.”

And when robots can work safely alongside humans, they can enhance people's lives and provide real and tangible benefits to society.

As more industries embrace robots and artificial intelligence, there are many lingering questions about what AI will ultimately be capable of doing, whether it will be able to take over the jobs that people have historically done, and what that could mean for humanity. But there are upsides to robots being able to take on certain types of jobs. They could work in fields with labor shortages, such as health care for older populations, and physically challenging jobs that may take a toll on workers’ health.

Lahijanian also believes that, when they're used correctly, robots and AI can enhance human talents and expand what we're capable of doing.

"Human-robot collaboration is about combining complementary strengths: humans contribute intelligence, judgment, and flexibility, while robots offer precision, strength, and reliability," he said.

"Together, they can achieve more than either could alone, safely and efficiently."

Beyond the Story

Our research impact by the numbers:

$742 million in research funding earned in 2023–24
No. 5 U.S. university for startup creation
$1.4 billion impact of 91ɫ��'s research activities on the Colorado economy in 2023–24

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91ɫ�� aerospace engineer Morteza Lahijanian is creating new algorithms that help robots complete tasks while keeping the humans in their midst safer.

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New bio-imaging device holds potential for eye and heart condition detection

Megan Maneval — Fri, 15 Aug 2025 17:50:25 +0000

New bio-imaging device holds potential for eye and heart condition detection Megan Maneval Fri, 08/15/2025 - 11:50

College of Engineering and Applied Science

Researchers at 91ɫ�� have developed a new bio-imaging device that can operate with significantly lower power and in an entirely non-mechanical way. It could one day improve detecting eye and even heart conditions.

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‘Cyborg jellyfish’ could aid in deep-sea research, inspire next-gen underwater vehicles

Amber Elise Carlson — Thu, 14 Aug 2025 18:09:03 +0000

‘Cyborg jellyfish’ could aid in deep-sea research, inspire next-gen underwater vehicles Amber Elise Carlson Thu, 08/14/2025 - 12:09

Amber Carlson

Nicole Xu stands behind the main jellyfish tank in her lab. (Credit: Glenn Asakawa)

In a towering aquarium in a darkened laboratory, moon jellyfish (Aurelia aurita) hover as if floating in space.

The glow of neon lights illuminates their translucent, bell-shaped bodies as they expand and contract rhythmically, their graceful tentacles flowing in wavelike patterns.

91ɫ�� engineer Nicole Xu watches them with fondness. Xu, an assistant professor in the Paul M. Rady Department of Mechanical Engineering, first became fascinated with moon jellies more than a decade ago because of their extraordinary swimming abilities. Today, Xu has developed a way to harness their efficiency and ease at moving through the water in ways that could make some types of aquatic research much easier.

She fits the jellies with microelectronic devices that activate key swimming muscles, enabling researchers to steer them toward remote ocean areas that are hard to access in any other way. Eventually, she plans to add sensors to the devices that can gather critical data on temperature, pH and other environmental characteristics.

“Think of our device like a pacemaker on the heart,” Xu said. “We're stimulating the swim muscle by causing contractions and turning the animals toward a certain direction.”

Going where humans can’t go

Nicole Xu reaches her hand into the tank and touches one of the moon jellyfish. (Credit: Glenn Asakawa)

As climate change accelerates, ocean waters are becoming less hospitable for a variety of marine life. The ocean is getting warmer and more acidic as it absorbs growing amounts of atmospheric carbon dioxide.

Measuring changes in the ocean is essential to understanding how human activities are impacting all life on Earth. But because the ocean is so vast and deep, some parts are hard to study without prohibitively expensive equipment. The cyborg jellies could offer a way for humans to wade into these relatively uncharted waters.

Moon jellyfish are the most energy-efficient animals on the planet. They’re prehistoric, with a simple body structure that has stayed the same for more than 500 million years. As invertebrates, they also lack a brain or spinal cord, though they do have basic organs and a pair of overlapping nerve nets. Importantly, the jellies do not have nociceptors, or sensory receptors that can detect potentially harmful stimuli.

Moon jellies can range from a centimeter to more than a foot in diameter. Their short, fine tentacles help them sting and catch prey like zooplankton, crustacean larvae and small fish. But thankfully for Xu, their sting cells can’t penetrate human skin.

Though they’re often found near coastlines, close to their favorite food sources, moon jellies live in diverse habitats worldwide and can swim to incredible depths: They’ve been found in some of the lowest places on Earth, including the Mariana Trench, which sits roughly 36,000 feet beneath the western Pacific Ocean’s surface at its deepest point.

Xu co-created the biohybrid robotic jellyfish concept with her former academic advisor about five years ago, and she first tested them in the field in 2020, steering them around shallow ocean waters off the coast of Woods Hole, Mass.

On top of the implications for ocean and climate research, Xu believes we can draw inspiration from the jellyfish.

“There’s really something special about the way moon jellies swim. We want to unlock that to create more energy-efficient, next-generation underwater vehicles,” she said.

Striving for ethical research

From left: Nicole Xu and graduate students Marshall Graybill and Charlie Fraga stand next to the main jellyfish tank in Xu's lab. (Credit: Glenn Asakawa)

Today, Xu spends much of her time studying precisely how moon jellies move through the water with such ease.

Xu, research associate Yunxing Su and graduate student Mija Jovchevska published a new study late last month that involved adding biodegradable particles to a jellyfish tank. The researchers then shone a laser through the tank to illuminate the suspended particles in the water and visualize how water flows when jellies swim.

In the past, researchers have used synthetic tracers such as silver-coated glass beads to look at underwater flow patterns, but the new study suggests biodegradable particles, such as corn starch, could be more sustainable, more affordable and less toxic alternatives.

She and graduate student Charlie Fraga are also working on making the jellyfish easier to steer in the wild. Going forward, Xu hopes to design other nature-inspired tools for studying the ocean.

There’s more to learn about the ethics of studying invertebrates. In a paper published earlier this year, Xu and others pointed out the need for more investigation of how research affects invertebrates. It was once widely believed that invertebrates couldn’t feel pain, but there is growing evidence that some do react to aversive stimuli.

Through all of her research, Xu says she strives to minimize harm to the animals she works with. When they’re stressed, moon jellies may secrete extra mucus, and they often stop reproducing. But Xu’s jellies have not shown increased mucus production, and small polyps—baby jellyfish the size of a pinhead whose tentacles are just beginning to form—line the inside of Xu’s jellyfish tanks.

“It's our responsibility as researchers to think about these ethical considerations up front,” Xu said. “But as far as we can tell, the jellyfish are doing well. They're thriving.”

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Our research impact by the numbers:

$742 million in research funding earned in 2023–24
No. 5 U.S. university for startup creation
$1.4 billion impact of 91ɫ��'s research activities on the Colorado economy in 2023–24

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91ɫ�� engineer Nicole Xu fits moon jellyfish with microelectronic devices that enhance their natural swimming ability and will one day be able to gather data.

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Who is afraid of the big, bad (dire) wolf?

Megan Maneval — Tue, 29 Jul 2025 16:16:22 +0000

Who is afraid of the big, bad (dire) wolf? Megan Maneval Tue, 07/29/2025 - 10:16

Colorado Arts and Sciences Magazine

Advancing science may make it possible to bring back extinct species like the dire wolf—but should it? A 91ɫ�� environmental studies and philosophy professor says the answer is complicated.

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Researchers test the trustworthiness of AI—by playing sudoku

Daniel William Strain — Mon, 28 Jul 2025 22:15:49 +0000

Researchers test the trustworthiness of AI—by playing sudoku Daniel William… Mon, 07/28/2025 - 16:15

Daniel Strain

Artificial intelligence tools called large language models (LLMs), such as OpenAI’s ChatGPT or Google’s Gemini, can do a lot these days—dispensing relationship advice, crafting texts to get you out of social obligations and even writing science articles.

But can they also solve your morning sudoku?

In a new study, a team of computer scientists from the 91ɫ�� decided to find out. The group created nearly 2,300 original sudoku puzzles, which require players to enter numbers into a grid following certain rules, then asked several AI tools to fill them in.

The results were a mixed bag. While some of the AI models could solve easy sudokus, even the best struggled to explain how they solved them—giving garbled, inaccurate or even surreal descriptions of how they arrived at their answers. The results raise questions about the trustworthiness of AI-generated information, said study co-author Maria Pacheco.

“For certain types of sudoku puzzles, most LLMs still fall short, particularly in producing explanations that are in any way usable for humans,” said Pacheco, assistant professor in the Department of Computer Science. “Why did it come up with that solution? What are the steps you need to take to get there?”

She and her colleagues published their results this month in Findings of the Association for Computational Linguistics.

Maria Pacheco

Fabio Somenzi

Ashutosh Trivedi

The researchers aren’t trying to cheat at puzzles. Instead, they’re using these logic exercises to explore how AI platforms think. The results could one day lead to more reliable and trustworthy computer programs, said study co-author Fabio Somenzi, professor in the Department of Electrical, Computer and Energy Engineering.

“Puzzles are fun, but they’re also a microcosm for studying the decision-making process in machine learning,” he said. “If you have AI prepare your taxes, you want to be able to explain to the IRS why the AI wrote what it wrote.”

Daily puzzle

Somenzi, who is a self-described sudoku fan, noted that the puzzles tap into a very human way of thinking. Filling out a sudoku grid requires puzzlers to learn and follow a set of logical rules. For example, you can’t enter a two in an empty square if there’s already a two in the same row or column.

Most LLMs today struggle at that kind of thinking, in large part because of how they’re trained.

To build ChatGPT, for example, programmers first fed the AI almost everything that had ever been written on the internet. When ChatGPT responds to a question, it predicts the most likely response based on all that data—almost like a computer version of rote memory.

“What they do is essentially predict the next word,” Pacheco said. “If you have the start to a sentence, what word comes next? They do that by referring to every sentence in the English language that they can get their hands on.”

Pacheco, Somenzi and their colleagues have joined a growing effort in computer science to merge those two ways of thinking—combining the memory of an LLM with a human brain’s capacity for logic, a pursuit known as “neurosymbolic” AI.

Anirudh Maiya and Razan Alghamdi, both former graduate students at 91ɫ��, were also co-authors of the new paper.

How’s the weather?

To begin, the researchers created sudoku puzzles of varying difficulty using a six-by-six grid. (A simpler version of the nine-by-nine puzzles you usually find online).

They then gave the puzzles to a series of AI models, including the preview of OpenAI’s o1 model—which, in 2023, represented the state-of-the-art for its kind of LLM.

The o1 model led the pack, solving roughly 65% of the sudoku puzzles correctly. Then the team asked the AI platforms to explain how they got their answers. That’s when the results got really wild.

“Sometimes, the AI explanations made up facts,” said Ashutosh Trivedi, a co-author of the study and associate professor of computer science at 91ɫ��. “So it might say, 'There cannot be a two here because there’s already a two in the same row,' but that wasn’t the case.”

In a telling example, the researchers were talking to one of the AI tools about solving sudoku when it, for unknown reasons, responded with a weather forecast.

“At that point, the AI had gone berserk and was completely confused,” Somenzi said.

The researchers hope to design their own AI system that can do it all—solving complicated puzzles and explaining how. They’re starting with another type of puzzle called hitori, which, like sudoku, involves a grid of numbers.

“People talk about the emerging capabilities of AI where they end up being able to solve things that you wouldn’t expect them to solve,” Pacheco said. “At the same time, it’s not surprising that they’re still bad at a lot of tasks.”

A team of computer scientists discovered that some AI large language models can solve sudoku puzzles, but even the best ones struggle to explain how they did it.

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Faster, cleaner, better: Revolutionary water treatment

Megan Maneval — Fri, 25 Jul 2025 12:59:14 +0000

Faster, cleaner, better: Revolutionary water treatment Megan Maneval Fri, 07/25/2025 - 06:59

College of Engineering and Applied Science

Anthony Straub is making revolutionary advances in water purification for life on Earth and in space with nanoscale membranes—thinner than 1/100th the width of a human hair.

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