Bennu is known as a carbonaceous asteroid, meaning it is rich in carbon-based material, including organic compounds. These compounds are important because they are similar to the chemical ingredients needed for life. The asteroid itself is made up of fragments from a much larger parent body that broke apart long ago. Because Bennu orbits relatively close to Earth, it became a prime target for NASA’s OSIRIS-REx mission.

Pristine Samples From the Early Solar System

One of the most valuable aspects of Bennu samples is that they have remained untouched by Earth’s atmosphere and environment. This makes them especially useful for scientists studying conditions in the early Solar System. By examining these samples, researchers can see how water, minerals, and organic matter originally formed and interacted billions of years ago.

In this study, Mehmet Yesiltas and his team focused on a specific sample labeled OREX-800066-3. This material was collected directly from Bennu by the OSIRIS-REx spacecraft and returned to Earth in September 2023. Because the sample was carefully sealed and protected, it provides a rare and reliable record of Bennu’s original chemistry.

Studying Bennu at the Nanoscale

To investigate the sample, the researchers used advanced techniques called nanoscale infrared spectroscopy and Raman spectroscopy. These methods allow scientists to identify chemical compounds by measuring how they interact with light. Importantly, they can do this at extremely small scales, down to about 20 nanometers. For comparison, a nanometer is one billionth of a meter, far smaller than anything visible to the human eye.

This level of detail revealed that Bennu’s internal chemistry is not uniform. Instead, the material forms three repeating types of organic-mineral regions, each with its own distinct composition.

Three Distinct Chemical Domains

The study identified three main types of regions within the sample. One type contains high amounts of aliphatic organic compounds, which are simple carbon-based molecules made of chains of carbon and hydrogen. Another region is rich in carbonate minerals, which often form in the presence of water and can provide clues about past watery environments. The third region contains organic compounds that include nitrogen, an element that plays a key role in biological molecules such as amino acids.

These differences show that Bennu’s chemistry varies significantly from place to place, even at extremely small scales.

Water’s Uneven Impact on Bennu

The uneven distribution of these chemical regions suggests that water did not affect Bennu in a single, uniform way. Instead, liquid water likely interacted with different parts of the asteroid under varying conditions, creating a patchwork of chemical environments. This process is known as nanoscale heterogeneity, meaning that the composition changes depending on the exact location being studied.

Despite this history of water interaction, the researchers found that fragile organic molecules were still preserved. This is an important discovery because it shows that key chemical ingredients can survive even when exposed to water-related changes.

Insights Into the Origins of Life’s Ingredients

Overall, the findings provide new insight into how water, minerals, and organic matter interacted on primitive asteroids like Bennu. These interactions are thought to have played a major role in shaping the early Solar System and may have contributed to the delivery of life’s building blocks to Earth.

By studying Bennu at such a fine scale, scientists are gaining a clearer picture of how complex chemistry developed in space long before planets like ours fully formed.

The research, published in the journal Advanced Materials, introduces a scalable method for producing these nanoscrolls from MXene precursors while precisely controlling their shape and chemical composition.

“Two-dimensional morphology is very important in many applications. However, there are applications where 1D morphology is superior,” said Yury Gogotsi, PhD, Distinguished University and Bach professor in Drexel’s College of Engineering, who was a corresponding author of the paper. “It’s like comparing steel sheets to metal pipes or rebar. One needs sheets to make car bodies, but to pump water or reinforce concrete, long tubes or rods are needed.”

From Flat Sheets to Tubular Nanostructures

The team created the nanoscrolls by rolling flat MXene flakes into tiny tubular structures that are about ten thousand times thinner than a water pipe. These tube-like materials can strengthen polymers and metals or guide the movement of ions in batteries and desalination systems with far less resistance.

“With standard 2D MXenes, the flakes lay flat on top of each other, which creates a confined-space and a difficult path for ions or molecules to navigate and move between the layers,” said Teng Zhang, PhD, a postdoctoral researcher in the College of Engineering and co-author of the study. “By converting 2D nanosheets into 1D scrolls, we prevent this nano-confinement effect. The open, tubular geometry effectively creates ‘highways’ for rapid transport, allowing ions to move freely.”

While similar structures made from graphene, such as carbon nanotubes, are already well known, producing consistent, high-quality MXene nanoscrolls has been difficult. MXenes offer advantages over graphene, including richer chemistry, easier processing, and higher conductivity, but earlier attempts to form scrolls often led to uneven results.

Scalable Method for Producing MXene Nanoscrolls

To make the nanoscrolls, researchers start with multilayer MXene flakes. By carefully adjusting the chemical environment, they use water to change the surface chemistry of the material. This triggers a structural imbalance called a Janus reaction, which creates internal strain within the layers. As this strain is released, the layers peel apart and curl into tight scrolls.

The team successfully applied this method to six types of MXenes, including two forms of titanium carbide, as well as niobium carbide, vanadium carbide, tantalum carbide, and titanium carbonitride. They were able to consistently produce 10 grams of nanoscrolls with controlled chemical and physical properties.

Improved Conductivity and Sensing Capabilities

The scroll-like structure not only improves electrical conductivity and mechanical strength, but also changes how the material interacts with molecules. This makes it especially promising for sensing applications and advanced composite materials.

“In a standard stacked 2D structure, the active sites for molecular adsorption are often hidden between layers, making it difficult for molecules, especially large biomolecules to reach them,” Gogotsi said. “The open, hollow structure of the scroll solves this by allowing the analytes easy access to the MXene surface. Combining with the material’s high conductivity and mechanical stiffness, this ensures we get a strong, stable signal. Thus, we envision the use of scrolls in biosensing. The same accessible surface of conductive scrolls may be useful for gas sensors, electrochemical capacitors and other devices that require access of ions and molecules to the surfaces.”

Applications in Wearable Electronics and Smart Textiles

The researchers also see strong potential for MXene nanoscrolls in wearable electronics, also known as ionotronic devices. In these systems, the scrolls could both reinforce materials and improve conductivity. Their rigid structure allows them to anchor within soft polymers, adding strength while maintaining a reliable conductive network.

This combination could lead to stretchable materials that continue to function even under repeated bending and movement.

The team also discovered that the orientation of nanoscrolls in solution can be controlled using an electric field. This means they can be aligned with fibers in textiles, creating more durable and conductive coatings for smart fabrics.

“Imagine manipulating millions of tubules 100 times thinner than a human hair to make them build a wire or stand up vertically to make a brush,” Zhang said. “This is real nanotechnology, as we can manipulate matter at the nanoscale. It is also a critical development for functional textiles, as the scrolls could be incorporated as reinforcement materials in synthetic fibers.”

Superconductivity and Future Quantum Applications

Looking ahead, the researchers plan to further investigate how these nanoscrolls behave at the quantum level, particularly their potential for superconductivity.

“Until now, superconductivity in this class of MXenes was limited to pressed pellets of particles and powders, having never been realized in solution-processed films with mechanical flexibility,” Gogotsi said. “By using niobium carbide scrolls, we observed the change of the material enough to enable superconductivity in free-standing, macroscopic films for the first time. The scrolling process introduces specific lattice strain and curvature that are absent in flat sheets. While the exact physical mechanism is still being explored, we hypothesize that this strain, combined with the continuous 1D structure, stabilizes the superconducting state.”

As interest in quantum materials grows, nanomaterials like MXenes are gaining attention for their ability to improve computing power and data storage. This work marks an important step forward by turning MXene superconductivity into a more practical and usable property.

“Using the methods described in this paper, we can now process superconducting MXenes into flexible films, coatings or wires at room temperature for potential superconducting interconnectors or quantum sensors,” Zhang said. “We expect many other interesting phenomena caused by scrolling and are going to study them.”

High blood pressure develops when the force of blood pushing through the arteries stays consistently elevated. Over time, this can damage blood vessels and significantly raise the risk of heart attacks, strokes, and other serious conditions.

Between 2017 and 2020, about 122.4 million (46.7%) adults in the United States were living with high blood pressure, contributing to more than 130,000 deaths. Diet plays a major role. Consuming too much sodium and not enough potassium are key contributors to elevated blood pressure.

Salt Substitutes: A Low-Cost but Underused Option

“Overall, less than 6% of all U.S. adults use salt substitutes, even though they are inexpensive and can be an effective strategy to help people control blood pressure, especially people with difficult-to-treat high blood pressure,” said lead study author Yinying Wei, M.C.N., R.D.N., L.D., and Ph.D. candidate in the departments of applied clinical research and hypertension section, cardiology division, at UT Southwestern Medical Center in Dallas.

“Health care professionals can raise awareness about the safe use of salt substitutes by having conversations with their patients who have persistent or hard-to-manage high blood pressure.”

Salt substitutes work by replacing some or all of the sodium in regular salt with potassium. While potassium salt has a similar flavor, it can develop a slightly bitter taste when heated.

Although many foods naturally contain sodium, most people consume the majority of it through processed foods, packaged items, and restaurant meals. The American Heart Association recommends limiting sodium intake to no more than 2,300 mg per day, with an ideal target of less than 1,500 mg for most adults, especially those with high blood pressure. Even reducing intake by 1,000 mg per day can lead to meaningful improvements in blood pressure and overall heart health.

Two Decades of Data Reveal a Persistent Gap

This study is the first to track long-term trends in salt substitute use across a nationally representative group of U.S. adults. Researchers analyzed data from the National Health and Nutrition Examination Survey (NHANES) collected between 2003 and 2020, focusing on products that replace traditional salt with potassium-enriched or alternative salts.

Who Can Safely Use Salt Substitutes?

The research paid special attention to people with high blood pressure and also examined a subgroup of adults considered safe candidates for salt substitutes. This included individuals with normal kidney function and those not taking medications or supplements that influence potassium levels.

Some salt substitutes contain potassium, which can build up to dangerous levels in people with kidney disease or those taking certain medications or supplements. High potassium levels can lead to abnormal heart rhythms. Because of this, people with high blood pressure should consult a health care professional before making the switch.

Key Findings: Usage Remains Surprisingly Low

The analysis showed that salt substitute use has remained consistently low across the U.S. population:

• Use peaked at 5.4% in 2013-2014 but dropped to 2.5% by 2017-March 2020. Data collection for 2020 ended early due to the pandemic.
• Among people eligible to safely use salt substitutes, only 2.3% to 5.1% reported using them.
• Usage was highest among individuals with high blood pressure controlled by medication (3.6%-10.5%), followed by those whose blood pressure remained uncontrolled despite treatment (3.7%-7.4%).
• Fewer than 5.6% of people with untreated high blood pressure or normal blood pressure used salt substitutes.
• People who ate at restaurants three or more times per week appeared less likely to use salt substitutes, although this difference was not statistically significant after adjusting for demographic factors.

“Salt substitute use remained uncommon over the last two decades including among people with high blood pressure,” Wei said. “Even among individuals with treated and poorly managed or untreated high blood pressure, most continued to use regular salt.”

Experts Call It a Missed Opportunity

“This study highlights an important and easy missed opportunity to improve blood pressure in the U.S. — the use of salt substitutes,” said Amit Khera, M.D., M.Sc., FAHA, an American Heart Association volunteer expert.

“The fact that use of salt substitutes remains so low and has not improved in two decades is eye-opening and reminds patients and health care professionals to discuss the use of these substitutes, particularly in visits focused on high blood pressure.”

Khera, who was not involved in the research, is a professor of medicine, clinical chief of cardiology, and director of preventive cardiology at UT Southwestern Medical Center in Dallas.

Study Limitations and Future Questions

The researchers note several limitations. Salt substitute use was self-reported, which may have led to underreporting or misclassification. The study also grouped all types of salt substitutes together, so it could not distinguish potassium-based products from other alternatives. In addition, the data did not track how much salt substitute participants used.

“Future research should explore why salt substitute-use remains low by investigating potential barriers, such as taste acceptance, cost and limited awareness among both patients and clinicians,” said Wei. “These insights may help guide more targeted interventions.”

Study Design and Participant Details

The analysis included 37,080 adults ages 18 and older (37.9% were aged 18-39, 36.9% were aged 40-59 years, and 25.2% were aged 60 and older). 50.6% of participants were women, 10.7% self-identified as non-Hispanic Black, and 89.3% reported other racial and ethnic backgrounds.

Participants were grouped based on whether they had high blood pressure (≥130/80 mm Hg) and whether they were using medication: controlled hypertension, uncontrolled hypertension, untreated hypertension, or normal blood pressure.

Salt use was categorized as ordinary salt (iodized salt, sea salt, kosher salt), salt substitute (potassium-enriched or other salt substitute), or no salt use.

A subgroup analysis focused on people eligible for salt substitutes, defined as those with healthy kidney function (estimated glomerular filtration rate ≥ 60) and no use of medications or supplements that affect potassium levels. Researchers also examined how often participants ate at restaurants. All results accounted for NHANES sampling methods and survey design.

Research Highlights

• Salt substitutes remain rarely used despite their ability to lower sodium intake and help manage blood pressure.
• Increasing awareness could help improve outcomes, especially for people with difficult-to-treat hypertension.
• The study was funded by the National Institutes of Health.

Note: The study featured in this article is a research abstract. Abstracts presented at American Heart Association’s scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

At the center of all this is growth hormone, which surges during sleep. But scientists have long puzzled over why poor sleep, especially the early deep stage known as non-REM sleep, leads to lower levels of this critical hormone.

Scientists Discover the Brain Circuit Behind It

Researchers at the University of California, Berkeley, have now uncovered the answer. In a study published in Cell, they mapped the brain circuits that control growth hormone release during sleep and identified a new feedback system that keeps those levels in balance.

This discovery offers a clearer understanding of how sleep and hormones work together. It may also open the door to new treatments for sleep disorders linked to metabolic diseases like diabetes, as well as neurological conditions such as Parkinson’s and Alzheimer’s.

“People know that growth hormone release is tightly related to sleep, but only through drawing blood and checking growth hormone levels during sleep,” said study first author Xinlu Ding, a postdoctoral fellow in UC Berkeley’s Department of Neuroscience and the Helen Wills Neuroscience Institute. “We’re actually directly recording neural activity in mice to see what’s going on. We are providing a basic circuit to work on in the future to develop different treatments.”

Lack of sleep does more than leave you tired. Because growth hormone helps control how the body processes sugar and fat, poor sleep can increase the risk of obesity, diabetes, and heart disease.

The Brain Regions Driving Growth Hormone

The system behind this process is buried deep in the hypothalamus, an ancient part of the brain shared by all mammals. Here, specialized neurons release signals that either trigger or suppress growth hormone.

Two key players are growth hormone releasing hormone (GHRH), which stimulates release, and somatostatin, which inhibits it. Together, they coordinate hormone activity across the sleep-wake cycle.

Once growth hormone enters the system, it activates the locus coeruleus, a brainstem region that controls alertness, attention, and cognitive function. Disruptions in this area are linked to a wide range of neurological and psychiatric disorders.

“Understanding the neural circuit for growth hormone release could eventually point toward new hormonal therapies to improve sleep quality or restore normal growth hormone balance,” said Daniel Silverman, a UC Berkeley postdoctoral fellow and study co-author. “There are some experimental gene therapies where you target a specific cell type. This circuit could be a novel handle to try to dial back the excitability of the locus coeruleus, which hasn’t been talked about before.”

How Sleep Stages Control Hormone Release

To study this system, researchers recorded brain activity in mice by inserting electrodes and stimulating neurons with light. Because mice sleep in short bursts throughout the day and night, they provided a detailed view of how growth hormone changes across sleep stages.

The team found that GHRH and somatostatin behave differently depending on whether the brain is in REM or non-REM sleep.

During REM sleep, both hormones increase, leading to a surge in growth hormone. During non-REM sleep, somatostatin drops while GHRH rises more modestly, still boosting hormone levels but in a different pattern.

A Surprising Feedback Loop in the Brain

The researchers also uncovered a feedback loop that links growth hormone to wakefulness. As sleep continues, growth hormone gradually builds up and stimulates the locus coeruleus, nudging the brain toward waking.

But there is a twist. When this brain region becomes too active, it can actually trigger sleepiness instead, creating a delicate balance between sleep and alertness.

“This suggests that sleep and growth hormone form a tightly balanced system: Too little sleep reduces growth hormone release, and too much growth hormone can in turn push the brain toward wakefulness,” Silverman said. “Sleep drives growth hormone release, and growth hormone feeds back to regulate wakefulness, and this balance is essential for growth, repair and metabolic health.”

Why It Matters for Brain and Body

This balance does more than affect physical growth. Because growth hormone works through brain systems that control alertness, it may also influence how clearly you think and how focused you feel.

“Growth hormone not only helps you build your muscle and bones and reduce your fat tissue, but may also have cognitive benefits, promoting your overall arousal level when you wake up,” Ding said.

Funding and Research Team

The research was supported by the Howard Hughes Medical Institute (HHMI) and the Pivotal Life Sciences Chancellor’s Chair fund. Yang Dan holds the Pivotal Life Sciences Chancellor’s Chair in Neuroscience. The study also included collaborators from UC Berkeley and Stanford University.