Researchers led by a team at the Center for Advanced Systems Understanding (CASUS) at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) have now introduced a dependable and reproducible theoretical approach to tackle this problem. Their predictions were validated through measurements on real material samples. The team believes this advance could significantly accelerate research on polyheptazine imides and spark rapid growth in the field.

Carbon Nitride Materials and Visible Light Absorption

Polyheptazine imides belong to the broader class of carbon nitrides. These materials consist of layered structures that resemble graphene but are built from nitrogen rich ring shaped molecular units.

While graphene is known for exceptional electrical conductivity, it does not function well as a photocatalyst. Polyheptazine imides differ in a crucial way. Their electronic band gaps allow them to absorb visible light, which makes them suitable for sunlight driven chemical reactions.

Carbon nitride materials also offer several practical advantages. They are relatively inexpensive to produce, non toxic, and thermally stable. However, early versions of these materials did not perform well as photocatalysts because their internal properties limited effective charge separation.

When a photon strikes a material, it can excite an electron and move it away from its original position, leaving behind a positively charged hole. If the electron quickly recombines with the hole, the energy is released only as heat or light instead of driving chemical reactions.

“Polyheptazine imides containing positively charged metal ions exhibit markedly improved charge separation. This feature renders them highly suitable for practical applications,” says first author Dr. Zahra Hajiahmadi.

Computer Modeling Speeds the Search for Better Catalysts

Improved materials are needed to unlock the economic potential of several photocatalytic processes. These include water splitting (to produce hydrogen as a fuel), carbon dioxide reduction (to produce basic carbohydrates as fuels or industrial chemicals), and hydrogen peroxide production (as a basic industrial chemical).

Designing a polyheptazine imide catalyst that performs well for a specific reaction requires careful control over many aspects of its structure. Creating and testing every possible material candidate in the laboratory would be unrealistic. Computational methods therefore play an essential role in narrowing down the possibilities.

“The design space is enormous,” explains Prof. Thomas D. Kühne, Director of CASUS, head of the CASUS research team “Theory of Complex Systems” and senior author of the study. “One can for example add functional groups on the surface or substitute specific nitrogen or carbon atoms with oxygen or phosphorus atoms.”

Kühne’s research group is developing advanced numerical techniques designed to be both efficient and capable of accurately reproducing the chemical and physical behavior of complex materials.

Systematically Testing 53 Metal Ions

A defining feature of polyheptazine imides is the presence of negatively charged pores within the material. These pores can host positively charged metal ions, which can significantly enhance catalytic performance.

Hajiahmadi’s work represents the first comprehensive investigation of how different metal ions influence the optoelectronic properties of these materials. The study examined 53 metal ions in total, categorizing them according to where they sit within the structure (in plane or between layers) and how they alter the geometry of the material (resulting in a distortion or not).

“We used a reliable and reproducible computational framework that goes beyond conventional modeling approaches,” says Hajiahmadi. “Standard computational studies of photocatalysts typically focus on ground-state properties and neglect excited-state effects, despite the fact that photocatalysis is inherently driven by photoexcited charge carriers. Specifically, we employ many-body perturbation theory methods.”

These methods begin with a simplified model system that does not include particle interactions. Interactions are then added as small corrections, allowing researchers to approximate how large numbers of particles affect each other. Although such calculations require substantial computing power and are rarely applied in this field, the new study demonstrates their value. The framework provides an accurate description of how these materials absorb light and how their electronic structure behaves under illumination.

Experiments Confirm Theoretical Predictions

Using their computational approach, the researchers explored how different metal ions alter the structure of the polyheptazine imide network. Their analysis revealed that introducing ions can cause measurable structural changes, including shifts in the spacing between layers and modifications to local bonding environments. These structural variations directly influence the electronic band structure and optical properties of the materials, affecting how efficiently they capture light.

To test their predictions, the team synthesized eight polyheptazine imide materials, each incorporating a different metal ion. The materials were then evaluated for their ability to catalyze hydrogen peroxide production.

“The results clearly showed a high degree of agreement to our predictions and outperformed competing calculation methods,” Hajiahmadi concludes.

Kühne adds: “If there was some doubt about polyheptazine imides being one of the most promising platforms for next-generation photocatalytic technologies, I believe this work put them to rest. The path toward the targeted design of efficient polyheptazine imide photocatalysts for sustainable reactions is clearer now. I firmly believe that it will be taken often and successfully.”

Melatonin appears to provide clear benefits for sleep difficulties in children with neurodevelopmental conditions. Yet for children without these conditions, strong evidence remains limited. Researchers are also concerned about inconsistent dosing in over the counter products, use without medical supervision, and a growing number of accidental ingestions. Taken together, these concerns point to the need for more caution, stronger regulation, and clearer evidence based guidance when melatonin is used to address sleep problems in children.

Why Families Are Turning to Melatonin

Sleep difficulties are becoming increasingly common among children and teenagers. Poor sleep can influence emotional regulation, cognitive development, and overall health. As parents look for quick and convenient solutions, melatonin supplements have become widely used because they are easy to obtain, often come in child friendly forms, and are widely perceived as a safe alternative to prescription medications.

Despite that perception, melatonin is actually a hormone that affects more than just sleep cycles. It plays roles in regulating the immune system, metabolism, and reproductive processes. Research on melatonin use in children is still uneven. Many studies only examine short term outcomes or focus on specific clinical populations. Because of these limitations, researchers say there is an urgent need to carefully evaluate the safety, effectiveness, and appropriate use of melatonin in pediatric care.

Review Examines Global Melatonin Use in Kids

A narrative review published in World Journal of Pediatrics, by researchers at Boston Children’s Hospital explored the rapid rise of melatonin use among children and adolescents worldwide. The review analyzed clinical evidence related to melatonin’s effectiveness, safety profile, and patterns of real world use.

Researchers found a clear mismatch between the widespread use of melatonin and the limited amount of long term scientific data available. The review also highlighted concerns about inappropriate use, inconsistent product quality, and the lack of strong regulatory oversight for sleep supplements marketed to children.

Evidence Shows Benefits for Some Children

According to the review, melatonin use among children has increased sharply over the past decade. This growth is especially noticeable in countries where the supplement is sold over the counter.

Strong clinical evidence supports melatonin’s short term benefits for children with neurodevelopmental disorders such as autism and attention deficit hyperactivity disorder. In these cases, melatonin can help children fall asleep more quickly, extend total sleep time, and improve overall quality of life for caregivers.

Limited Data for Typically Developing Children

The situation is less clear for children who do not have underlying developmental conditions. Research in this group is limited and often inconsistent. Most randomized clinical trials have been short in duration and focus primarily on older children or teenagers. As a result, researchers cannot draw strong conclusions about younger children, even though melatonin use in that age group is becoming more common.

Long term safety data are especially limited. Scientists still have unanswered questions about whether melatonin could influence puberty, immune function, metabolism, or neurological development when used over extended periods.

Safety Concerns About Melatonin Products

The review also highlights several safety issues that may occur outside controlled clinical environments. Testing of commercial melatonin supplements has revealed major differences between labeled doses and the actual amount of melatonin contained in some products. In some cases, supplements contained several times the stated dose or unexpected compounds such as serotonin.

Data from pediatric poison control centers also show a sharp increase in accidental melatonin ingestions among children. Young children appear particularly vulnerable, often due to gummy formulations that resemble candy and improper storage at home. These findings suggest that the risks associated with real world melatonin use may be higher than previously assumed.

Experts Urge Careful and Limited Use

Researchers caution that melatonin should not be treated as a quick fix for childhood sleep problems. Although it can be useful in certain carefully selected situations, particularly when guided by a healthcare professional, it should not replace thorough sleep assessments or behavioral interventions.

The review stresses that both clinicians and caregivers should view melatonin as a biologically active hormone rather than a harmless supplement. Without stronger evidence and better regulation, routine or unsupervised use could expose children to unnecessary risks while drawing attention away from proven non pharmacological strategies that support healthy sleep.

Behavioral Sleep Strategies Remain First Line Treatment

The findings have important implications for pediatric medicine, public health policy, and caregiver education. Behavioral approaches to sleep should remain the primary treatment for childhood insomnia. These strategies include maintaining consistent bedtime routines, limiting screen exposure before bed, and setting age appropriate sleep expectations.

If melatonin is used, the review recommends starting with the lowest effective dose, limiting the duration of treatment, and using it only under medical supervision. Researchers also emphasize the need for stronger oversight of melatonin products designed for children, clearer labeling standards, and more long term clinical research. These steps could help ensure that children receive safe, effective, and evidence based support for healthy sleep.

Fast radio bursts are incredibly powerful flashes of radio energy that travel across vast distances in the universe. Scientists believe they are produced by extreme astrophysical events, though the exact cause remains uncertain. Since 2018, the Canadian Hydrogen-Intensity Mapping Experiment, or CHIME, has detected thousands of these bursts. However, determining their exact positions in the sky has remained a major challenge.

CHIME Outrigger Array Pinpoints the Burst

The newly detected signal, named FRB 20250316A and nicknamed RBFLOAT (“Radio Brightest Flash Of All Time”), was localized with remarkable precision using the CHIME/FRB Outrigger array. These smaller versions of the CHIME instrument are installed in British Columbia, Northern California and West Virginia. Working together, they allow astronomers to use Very Long Baseline Interferometry (VLBI), a technique that combines signals from widely separated telescopes to determine an object’s position in the sky with exceptional accuracy.

“We were ultimately extremely lucky that we were able to pinpoint the precise sky position of this rare event,” said Mattias Lazda, doctoral student at the University of Toronto, and an author on both papers. “A few hours after we detected it, we experienced a power outage at one of our telescope sites that played a critical role in telling us where the burst came from. Had the event happened any later that day, we would’ve completely missed our chance.”

A Powerful Burst From a Nearby Galaxy

Although fast radio bursts rank among the most intense radio sources known, they appear only briefly. Each burst typically lasts from a few milliseconds to a few seconds, temporarily shining brighter than every other radio signal in its host galaxy. RBFLOAT, detected on March 16, 2025, lasted about one fifth of a second.

“Cosmically speaking, this fast radio burst is just in our neighborhood,” says Kiyoshi Masui, associate professor of physics and affiliate of MIT’s Kavli Institute for Astrophysics and Space Research, and a U of T alum. “This means we get this chance to study a pretty normal FRB in exquisite detail.”

The burst appeared exceptionally bright partly because its source lies relatively close to Earth. It originated near the outer region of the galaxy NGC 4141, located about 130 million light-years away in the constellation Ursa Major. Researchers were able to narrow the signal’s origin to a region only 45 light-years across, which is smaller than the typical size of a star cluster. Achieving this level of precision is comparable to spotting a guitar pick from 1000 kilometers away.

“The discovery was very exciting, because we had our brightest ever event right after all three outriggers were online,” said Amanda Cook, Banting Postdoctoral Researcher at McGill University and a U of T alum who led the paper describing RBFLOAT. “Immediately, even though it was a Sunday afternoon, a bunch of us piled into a zoom room and started hacking away at the research, hoping to get follow-up observations on source as quickly as possible.”

JWST Observations Reveal a Faint Infrared Signal

The precise location provided by the CHIME/FRB Outrigger array allowed the team to conduct follow-up observations with the James Webb Space Telescope (JWST). During those observations, scientists detected a faint infrared signal at the same location where RBFLOAT originated. The finding was unexpected, and researchers are still exploring what it might represent. One possibility is that the signal comes from a red giant star, while another idea is that it could be a fading light echo related to the burst itself.

“The high resolution of JWST allows us to resolve individual stars around an FRB for the first time. This opens the door to identifying the kinds of stellar environments that could give rise to such powerful bursts, especially when rare FRBs are captured with this level of detail.” said Peter Blanchard, a Harvard postdoctoral fellow and lead author of the companion paper describing the JWST observation.

A Burst That Challenges Current Theories

Even though this event is the brightest FRB ever detected by CHIME, astronomers have not observed any repeat bursts from the same source. Scientists examined hundreds of hours of CHIME data covering the region over more than six years but found no additional signals.

“This burst doesn’t seem to repeat, which makes it different from most well-studied FRBs,” said Cook. “That challenges a major idea in the field, that all FRBs repeat, and opens the door to reconsidering more ‘explosive’ origins for at least some of them.”

Two scientific papers describing the discovery were published in the Astrophysical Journal Letters. One focuses on the original radio detection and precise localization of the burst, while the other reports the JWST near-infrared observations of the same region. Together, the studies provide new insights into fast radio bursts and suggest they could become valuable tools for studying the universe, rather than remaining mysterious cosmic oddities.

The research, published in the Journal of Geophysical Research – Planets, focuses on ancient sand dunes located in Gale Crater, an area explored by NASA’s Curiosity rover. According to the study, these dunes slowly hardened into rock billions of years ago after interacting with groundwater moving beneath the Martian surface.

Curiosity Rover Data and Earth Desert Comparisons

The investigation was led by Dimitra Atri, Principal Investigator of NYUAD’s Space Exploration Laboratory, together with research assistant Vignesh Krishnamoorthy. To better understand what happened on Mars, the team compared observations from the Curiosity rover with similar rock formations found in the deserts of the United Arab Emirates that formed under comparable conditions on Earth.

Their analysis suggests that water from a nearby Martian mountain gradually seeped into the dunes through tiny fractures. As the moisture moved upward through the sand, it left behind minerals such as gypsum, which is commonly found in desert environments on Earth. These minerals are especially important to scientists because they can capture and preserve traces of organic material. As a result, such deposits are considered promising places for future missions searching for evidence of ancient life.

Subsurface Water May Have Supported Microbial Life

“Our findings show that Mars didn’t simply go from wet to dry,” said Atri. “Even after its lakes and rivers disappeared, small amounts of water continued to move underground, creating protected environments that could have supported microscopic life.”

New Clues About Mars’ Evolution and Habitability

The discovery sheds new light on how Mars changed over billions of years. It also strengthens the idea that underground environments could be some of the best places to look for signs of past life on the planet.

The work was supported by the NYUAD Research Institute and carried out at NYUAD’s Center for Astrophysics and Space Science. The center conducts advanced research aimed at improving scientific understanding of the universe while supporting the United Arab Emirates’ expanding role in global space exploration. The project also involved collaboration with James Weston of NYUAD’s Core Technology Platform and Panče Naumov’s research group.

For roughly six months, NASA’s Curiosity rover has been studying an area covered with geological features known as boxwork. These formations appear as narrow ridges about 3 to 6 feet (1 to 2 meters) tall separated by sandy depressions. Stretching across the terrain for miles, the crisscrossing ridges hint that groundwater once flowed through this region of Mars later than scientists previously believed. If that is true, it raises new questions about how long microscopic life might have survived on the planet billions of years ago, before its rivers and lakes disappeared and Mars became the cold desert we see today.

From orbit, the boxwork ridges create patterns that look like massive spiderwebs spread across the landscape. Researchers believe the shapes formed when groundwater moved through fractures in the bedrock, depositing minerals along those cracks. Over time, the mineral deposits hardened the fractured zones into ridges. Surrounding rock that lacked this reinforcement gradually eroded away, leaving behind the web-like network visible today.

Before Curiosity reached this region, scientists could only study the formations from orbital images, leaving many questions about their true structure and origin.

Exploring Martian Boxwork Up Close

Boxwork formations also exist on Earth, but they are usually only a few centimeters tall and often appear in caves or dry sandy environments. The Martian versions are far larger. To understand them better, the Curiosity team aimed to investigate the ridges directly and collect detailed measurements.

Navigating the terrain has not been easy. Engineers must carefully guide Curiosity, an SUV-size rover weighing nearly a ton (899 kilograms), along ridge tops that are sometimes only slightly wider than the rover itself.

“It almost feels like a highway we can drive on. But then we have to go down into the hollows, where you need to be mindful of Curiosity’s wheels slipping or having trouble turning in the sand,” said operations systems engineer Ashley Stroupe of NASA’s Jet Propulsion Laboratory in Southern California, which built Curiosity and leads the mission. “There’s always a solution. It just takes trying different paths.”

Scientists are also working to understand how such an extensive network of ridges formed on Mount Sharp, the 3-mile-tall (5-kilometer-tall) mountain that Curiosity has been climbing. Each layer of the mountain represents a different chapter in Mars’ ancient climate history. As the rover ascends, the landscape increasingly shows signs that water gradually disappeared over time, although occasional wetter periods allowed rivers and lakes to return.

“Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high,” said Tina Seeger of Rice University in Houston, one of the mission scientists leading the boxwork investigation. “And that means the water needed for sustaining life could have lasted much longer than we thought looking from orbit.”

Evidence of Ancient Groundwater

Earlier satellite images revealed another intriguing feature: dark lines running through the spiderweb-like ridges. In 2014, researchers suggested these streaks might represent central fractures where groundwater once seeped through cracks in the rock and concentrated minerals.

Curiosity’s close examination has confirmed that these dark lines are indeed fractures, supporting the idea that groundwater shaped the formation of the ridges.

The rover also spotted small, bumpy structures called nodules. These textures are commonly linked to ancient groundwater activity and have been observed by Curiosity and other Mars missions in the past. Surprisingly, the nodules were not located near the central fractures. Instead, they appeared along the sides of the ridges and within the sandy hollows between them.

“We can’t quite explain yet why the nodules appear where they do,” Seeger said. “Maybe the ridges were cemented by minerals first, and later episodes of groundwater left nodules around them.”

Curiosity Acts as a Mobile Chemistry Lab

A key part of Curiosity’s mission involves collecting rock samples with a drill attached to the end of its robotic arm. The drill grinds rock into powder, which is then delivered to sophisticated instruments inside the rover for analysis.

Last year, scientists analyzed three samples taken from the boxwork region. One came from the top of a ridge, another from bedrock inside a hollow, and a third from an area Curiosity passed through before reaching the ridges. Using X-ray analysis and a high-temperature oven, the rover detected clay minerals within the ridge and carbonate minerals in the hollow. These discoveries provide additional hints about the processes that formed the unusual terrain.

More recently, the rover collected a fourth sample for a specialized analysis reserved for particularly interesting targets. After the powdered rock was heated in the rover’s oven, chemical reagents were introduced to perform what scientists call wet chemistry. This method helps reveal certain organic compounds, carbon-based molecules that play an important role in the chemistry of life.

Continuing the Search for Mars’ Climate History

Curiosity is expected to move on from the boxwork region sometime in March. The area lies within a layer of Mount Sharp rich in salty minerals known as sulfates. These minerals formed as water on Mars gradually disappeared.

Over the coming year, the rover will continue traveling through this sulfate-rich layer, gathering new clues about how the climate of the ancient Red Planet changed billions of years ago.

About the Curiosity Rover

Curiosity was built by NASA’s Jet Propulsion Laboratory, which is managed by Caltech in Pasadena, California. JPL operates the mission for NASA’s Science Mission Directorate in Washington as part of NASA’s Mars Exploration Program portfolio.