Atrial fibrillation is a common heart rhythm condition in older adults and also affects many people living with Alzheimer’s disease. Doctors often prescribe blood thinners to these patients to reduce the chance of blood clots and stroke. Earlier research has suggested that anticoagulant treatment may lower the risk of developing dementia, but far less is known about whether these drugs influence cognitive decline after Alzheimer’s disease has already been diagnosed.

“There are reasons to believe that the treatment could have a positive effect on cognition, for example by improving blood flow and reducing small-scale damage in the brain,” says Maria Eriksdotter, professor at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, and senior consultant in geriatric medicine at Karolinska University Hospital, who led the study.

Comparing Newer and Older Blood Thinners

Researchers analyzed information from SveDem (Swedish Register for Cognitive Disorders/Dementia), a national quality registry, and included 7,308 people diagnosed with both atrial fibrillation and Alzheimer’s disease.

Participants were placed into three matched groups. One group received newer anticoagulants known as NOACs, another was treated with the older blood thinner warfarin (Waran), and the third did not receive any anticoagulant medication.

To track changes in thinking and memory over time, researchers used the standardized Mini-Mental State Examination (MMSE).

Slower Cognitive Decline With NOACs

People taking NOACs showed a significantly slower decline in cognitive function than those treated with warfarin or those who received no anticoagulant medication.

The difference amounted to slightly more than 0.2 MMSE points per year. While that change is relatively small over a single year, the researchers say it could become more meaningful if it continues over a longer period.

“The difference is modest for an individual patient from one year to the next, but over a longer period even such an effect could influence how cognitive function develops. Our findings suggest that NOAC treatment may also be significant for cognition in this patient group,” says Nanbo Zhu, researcher at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet.

Lower Risks of Stroke and Other Complications

The potential benefits were not limited to cognition. Compared with people who did not receive anticoagulants, those treated with NOACs also had lower risks of death, stroke, blood clots and fractures.

Warfarin was also associated with lower risks of death, stroke, and blood clots. However, people taking warfarin had a higher risk of major bleeding.

Why the Findings Need Caution

The researchers emphasize that the study has important limitations. Because it was observational, the results cannot prove that NOACs directly caused the slower cognitive decline or the other health benefits seen in the data.

Some factors that could affect both which treatment a patient received and how their health changed over time could not be fully evaluated. The researchers also note that some participants may have switched from one medication to another during the follow-up period.

The study was funded by, amongst others, the Swedish Research Council, the Swedish Brain Foundation, CIMED, ALF project funding and Karolinska Institutet funds. Maria Eriksdotter has participated as a consultant in one-off meetings with BioArctic AB, Roche, Eli Lilly, Biogen/Eisai and Novo Nordisk, and has given lectures at symposia sponsored by Roche and BioArctic/Eisai. No other conflicts of interest are reported.

The findings came from a study published on March 16, 2023, in the open access journal PLOS Biology, led by Lige Leng of Xiamen University in Xiamen, China, and colleagues. The work identified a possible connection between brain inflammation, metabolism, and aging throughout the body. Research published since then has added to that picture, while also showing why the supplement findings require careful interpretation.

How a Brain Protein Could Influence Aging

The researchers focused on the hypothalamus, a small brain region that helps coordinate metabolism and other essential functions. It also appears to influence how the body ages. As inflammatory signaling increases in this region, it can contribute to changes both within the brain and in tissues elsewhere in the body.

Before the 2023 study, Leng and colleagues had found that Menin helps restrain inflammation in the hypothalamus. That raised an important question: Could losing some of this protection help set age-related decline in motion?

The team found that Menin levels fell with age in certain neurons within the ventromedial hypothalamus, an area involved in regulating metabolism. The same decline was not seen in astrocytes and microglia, two types of cells that support and protect the brain. This suggested that the change was specific to particular cells rather than a uniform loss across the region.

To investigate whether Menin loss could actually contribute to aging, rather than simply accompany it, the researchers created conditional knockout mice. These animals were genetically engineered so that Menin could be selectively removed. Reducing Menin in younger mice increased hypothalamic inflammation and brought on several aging-related traits, including lower bone mass, thinner skin, cognitive decline, and a modestly shorter lifespan.

The D-Serine Connection

Menin loss also disrupted a chemical pathway important for communication between brain cells. Mice with less Menin had lower levels of D-serine, an amino acid that helps activate receptors involved in learning and memory. These receptors help neurons adjust the strength of their connections, a process essential for storing information.

An enzyme involved in D-serine production (which was in turn regulated by Menin) became less active, reducing the amino acid’s supply. The findings suggested that Menin could influence cognition not only through inflammation, but also by helping maintain the chemistry that supports brain signaling.

D-serine is sometimes used as a dietary supplement, but an important distinction can get lost in discussions of food sources. Serine occurs in foods such as soybeans, eggs, fish, and nuts, while the form incorporated into dietary proteins is L-serine. The body can convert L-serine into D-serine, but the two forms are not interchangeable, and eating these foods is not equivalent to receiving the experimental D-serine treatment.

Restoring Menin in Older Mice

The researchers next tested whether raising Menin levels could improve the condition of elderly (20-month-old) mice. They delivered the gene for Menin into the hypothalamus, allowing cells in that region to produce more of the protein.

Thirty days later, the treated mice had improvements in skin thickness and bone mass, along with better performance on tests of learning, cognition, and balance. The changes were accompanied by higher D-serine levels in the hippocampus, a brain region essential for learning and memory. The study also reported that restoring Menin extended lifespan in the treated mice.

A separate experiment tested a simpler approach: giving mice D-serine in their drinking water for three weeks. This improved cognitive performance, including in older animals. However, the supplement did not reproduce the broader improvements in physical aging traits seen after Menin restoration. The distinction matters: the study did not show that taking D-serine reversed aging throughout the body.

At the time, Leng described the potential significance of the findings:

“We speculate that the decline of Menin expression in the hypothalamus with age may be one of the driving factors of aging, and Menin may be the key protein connecting the genetic, inflammatory, and metabolic factors of aging. D-serine is a potentially promising therapeutic for cognitive decline.”

Leng added, “Ventromedial hypothalamus (VMH) Menin signaling diminished in aged mice, which contributes to systemic aging phenotypes and cognitive deficits. The effects of Menin on aging are mediated by neuroinflammatory changes and metabolic pathway signaling, accompanied by serine deficiency in VMH, while restoration of Menin in VMH reversed aging-related phenotypes.”

What Later Research Has Added

Subsequent studies have explored related mechanisms, although they should not be treated as direct confirmation of the entire Menin aging pathway.

A study published in the Journal of Physiology and Biochemistry in March 2024 examined Menin in cultured mouse hippocampal cells exposed to the stress hormone corticosterone. A compound called itaconate increased Menin levels and reduced inflammation and a form of cell death. When the researchers silenced Menin, that protection disappeared. The result supported a protective role for Menin in another experimental setting, but it was a cell study, not a demonstration of slower aging in animals or people.

Other work has strengthened the case that communication between the hypothalamus and the rest of the body can influence aging. In a 2024 Cell Metabolism study, researchers at Washington University School of Medicine identified a different group of hypothalamic neurons that communicates with fat tissue. Interventions that maintained or stimulated this system increased physical activity and extended lifespan in mice. The study involved a different molecular pathway from Menin, but reinforced the broader idea that brain signals can affect aging beyond the brain.

A much larger view emerged in January 2025, when an Allen Institute team reported an analysis of roughly 1.2 million mouse brain cells in Nature. Some of the cell types most sensitive to aging were concentrated around the hypothalamus’s third ventricle, a fluid-filled cavity. Many showed reduced activity in genes associated with neuronal function alongside increased activity in genes related to immune responses. That study mapped changes associated with aging rather than testing a treatment, but it highlighted the hypothalamus as an important area for further investigation.

Why More D-Serine Is Not Necessarily Better

Later research also complicates the idea that increasing D-serine should always benefit an aging brain.

In April 2025, a study in Cellular and Molecular Life Sciences examined mice engineered to develop features of Alzheimer’s disease. In that model, an early rise in D-serine accompanied disruptions in brain signaling. Genetically removing the enzyme that produces D-serine prevented or reduced several later cognitive problems. This was a different biological setting from the Menin experiments, but it demonstrated that D-serine can have different effects depending on the underlying disease process.

Research published on September 16, 2026, in the Journal of Alzheimer’s Disease pointed in another direction. In a different Alzheimer’s mouse model, a diet enriched with L-serine increased blood levels of both L-serine and D-serine and partially restored measures of new neuron production in the hippocampus. It did not improve the buildup of amyloid, a protein associated with Alzheimer’s disease. Importantly, this experiment tested L-serine and the production of new neurons, not D-serine supplementation as a treatment for human aging.

Taken together, these findings suggest that serine metabolism is a promising research target, but not a simple case of more being better. The form of serine, the condition being studied, and the outcome being measured all matter. Neither study directly confirms or overturns the original Menin results.

What the Findings Mean for People

There is some human research on D-serine, although it does not establish an aging treatment. A small randomized study published in 2016, before the Menin work, tested a single dose in 50 healthy older adults. Participants improved on one measure of a computerized maze task, but the researchers found no significant benefit on the other cognitive tests or mood measures. The experiment did not establish lasting memory benefits, slower aging, or the safety of prolonged use in older adults.

The Menin findings leave several important questions unresolved. Researchers still need to determine what causes the protein to decline with age, how much of the resulting physical and cognitive deterioration can be prevented, and how long any benefits might last. They also need to understand whether altering Menin or supplementing D-serine could produce unintended effects.

The central possibility remains compelling: some changes associated with aging may be influenced by signals originating in a small part of the brain. Understanding those signals could reveal ways to protect function later in life. For now, however, the evidence points to an experimental pathway worth investigating, not a supplement proven to turn back human aging.

Nanoplastics are ultrafine plastic particles measuring less than 1 micrometer (μm; one-thousandth of a millimeter) that are generated during the degradation of larger plastic materials. These particles can enter the human body through food and drinking water. Due to their extremely small size, nanoplastics may cross the intestinal barrier and accumulate in organs such as the kidneys and brain. However, biological strategies to reduce nanoplastic accumulation in the gastrointestinal tract remain at an early stage of research.

A research team led by Drs. Se Hee Lee and Tae Woong Whon at WiKim investigated the adsorption capacity of a kimchi-derived lactic acid bacterium, Leuconostoc mesenteroides CBA3656, against polystyrene nanoplastics (PS-NPs).

Under standard laboratory conditions, strain CBA3656 showed a high adsorption efficiency of 87%, comparable to that of the reference strain Latilactobacillus sakei CBA3608 (85%). However, a notable difference was observed under simulated human intestinal conditions. While the adsorption rate of strain CBA3608 decreased sharply to 3%, strain CBA3656 maintained a substantially higher adsorption level of 57%. These results indicate that the kimchi-derived strain can stably bind nanoplastics even in environments resembling the human intestinal tract.

Significant findings were also observed in animal experiments using a germ-free mouse model. Compared with the control group that did not receive probiotics, both male and female mice administered strain CBA3656 showed more than a twofold increase in nanoplastics detected in feces. This result suggests that the probiotic may contribute to the excretion of nanoplastics by binding to them in the intestine.

This study provides scientific evidence that kimchi-derived lactic acid bacteria may interact with environmental micropollutants beyond their traditional role in fermentation. The findings provide new insight into potential biological mechanisms that may help reduce nanoplastic accumulation in the gastrointestinal tract.

“Plastic pollution is increasingly recognized not only as an environmental issue but also as a public health concern,” said Dr. Sehee Lee, the lead researcher of the study. “Our findings suggest that microorganisms derived from traditional fermented foods could represent a new biological approach to address this emerging challenge. We will continue to expand the scientific value of kimchi microbial resources to contribute to public health and environmental solutions.”

The discovery also highlights the importance of cryptic diversity, in which animals that look nearly identical can actually belong to separate species. Researchers distinguished the new frog by combining several lines of evidence, including its DNA and distinctive call.

The findings were published in the journal Ichthyology & Herpetology. The research team includes Célio F. B. Haddad, a professor at São Paulo State University (UNESP), and Thiago R. Carvalho, a professor at the Federal University of Minas Gerais (UFMG). Both are part of the Center for Research on Biodiversity Dynamics and Climate Change (CBioClima), a Research, Innovation, and Dissemination Center (RIDC) funded by FAPESP.

A New Frog From the Western Amazon

The discovery grew out of field expeditions in the Upper Juruá River region of western Acre. Scientists surveyed forest fragments near the Moa and Crôa rivers, close to Cruzeiro do Sul.

Confirming that the frog represented a new species required far more than simply examining its appearance. The team compared DNA data, recordings of its calls, body shape (morphology), habitat information, and specimens preserved in scientific collections.

The name varcena refers specifically to Amazonian floodplain forests, ecosystems that are submerged during certain parts of the year. That is the environment where the newly described frog was found.

Its habitat is particularly notable because members of the genus Adenomera are generally associated with dryland forests. Finding Adenomera varcena in seasonally flooded forest therefore reveals a previously unknown habitat association for the genus.

DNA and a Distinctive Call Reveal Its Identity

Although Adenomera varcena closely resembles related frogs, researchers found physical and acoustic features that set it apart. One visible difference is the absence of a dark spot on the underside of its forearm.

Its mating call also has a distinctive signature. The frog produces a short sound at a slow rhythm, along with other specific acoustic characteristics that helped researchers separate it from closely related species.

The discovery offers another example of how much Amazonian biodiversity remains undocumented, particularly among animals that appear almost identical on the outside. This type of hidden variation is known as cryptic diversity.

Researchers also found evidence that numerous Adenomera lineages have still not been formally described. That suggests scientists have much more work to do to understand how these amphibians diversified throughout the Amazon.

Climate Change Could Alter Its Flooded Habitat

Scientists do not yet know enough about the ecology and life history of Adenomera varcena to determine how environmental changes could affect it.

“Since we don’t yet know in detail the species’ ecological requirements and its natural history [reproductive period and mode], it’s difficult to predict the impacts of climate change, which may alter the seasonal flooding patterns of the floodplain forest ecosystem in this region of the Amazon,” says Carvalho. “Since the species has a preference for this specific ecosystem, it’s possible to suggest that these changes in flood dynamics may influence – though we don’t know to what extent – the species’ reproductive behavior. In a scenario of accelerated loss of natural areas, the formal description of a new species underscores how much more effort we still need to make to advance studies on our biodiversity. Species may become locally extinct even before they’re formally recognized as species through their naming and description.”

Because the frog appears to favor this particular floodplain ecosystem, shifts in the timing or extent of seasonal flooding could potentially affect its reproduction. However, researchers do not yet know how large that effect might be.

A Race to Catalog Brazil’s Biodiversity

Haddad notes that new amphibian species are still being discovered regularly, but scientists face increasing pressure to document Brazil’s biodiversity as natural habitats continue to disappear.

“Currently, the pace of ecosystem destruction outpaces the capacity of taxonomic studies to keep up. Consequently, species that haven’t yet been described are omitted from lists of threatened fauna and remain legally and environmentally vulnerable. Thus, describing new species serves as a tool that aids in their protection. Furthermore, deepening our knowledge of actual biodiversity expands our understanding of the evolution of organisms, consolidating an essential pillar for both pure science and conservation strategies,” he says.

Formally identifying a species can therefore have practical consequences for conservation. Animals that have not yet been recognized scientifically may be absent from threatened species lists, environmental policies, and extinction risk assessments.

The identification of Adenomera varcena expands scientific knowledge of Neotropical amphibians while also illustrating why taxonomy matters for conservation. Rare species and those restricted to highly specific environments can be especially easy to overlook if they have not been formally described.

The project brought together researchers from Brazilian and international institutions, including UFMG, UNESP, the University of São Paulo (USP), the Federal University of Uberlândia (UFU), and the University of Ecuador (PUCE-Quito).

Many of these particles are linked to cosmic rays, extremely energetic particles that can come from exploding stars and other violent events far beyond our solar system. When cosmic rays strike atoms high in Earth’s atmosphere, they create showers of secondary particles. Among them are muons, which can travel through the atmosphere and even penetrate underground.

University of Delaware physics professor Spencer Axani has developed a device called CosmicWatch that makes it much easier to detect these otherwise invisible particles. The technology is now being used by everyone from high school students to professional researchers.

A $100 Detector for Invisible Cosmic Particles

CosmicWatch is roughly the size of a box of animal crackers. Built from electronic components costing around $100, the detector flashes and records a count whenever a muon passes through it. The information is stored so users can later download and analyze the data.

The device was initially created as an inexpensive way to introduce students to particle physics. Since then, however, CosmicWatch has found a role in international astrophysics research as well.

“CosmicWatch detectors allow us to do far more physics at a dramatically lower cost, in a compact and portable form, opening the door to many new kinds of experiments and outreach opportunities,” Axani said.

What Muons Can Reveal About the Universe

Scientists study muons because they can provide clues about some of the most powerful events in the cosmos, including supernovae, gamma-ray bursts and blazars. By measuring muons, researchers can estimate properties of the original cosmic ray, including its energy, mass and direction.

Muon flux also played an important role in physics history. In the early 1940s, measurements of these particles provided one of the first experimental confirmations of Einstein’s theory of special relativity.

Muons are useful for studying objects on Earth as well. The particles can travel through solid materials such as walls, rock, or humans without causing damage. Because they leave behind a detectable energy trail, scientists can use them to image structures hidden behind large amounts of matter. In 2016, muon technology uncovered an unknown corridor in the Great Pyramid of Giza.

The challenge is that conventional muon detectors are often bulky and expensive. That limits both the experiments researchers can perform and the number of schools that can give students hands-on access to the technology.

“A typical undergraduate physics lab course uses a rack of electronics about the size of a small bookshelf to measure muons,” Axani said.

How CosmicWatch Began

Axani first created CosmicWatch in 2017 while he was a graduate student at MIT. His original goal was to build a compact, energy-efficient muon detector for use at the IceCube observatory in Antarctica.

IceCube is a massive detector buried beneath the ice that searches for neutrinos, another type of subatomic particle. A muon detector is useful because it helps researchers distinguish muons from the neutrinos they are trying to identify.

As the project developed, Axani realized the same technology could be made portable and inexpensive enough for educational use. CosmicWatch then evolved into an outreach tool for teaching particle physics.

After joining the UD faculty in 2022, Axani continued refining the design. He recently released the third version of CosmicWatch. Improvements described in an article in the Journal of Instrumentation in October allow the new detector to monitor its surroundings, tolerate high radiation levels, and gather data more quickly.

“Even though I had studied cosmic rays, I didn’t fully appreciate the rich physics behind the working of these detectors to actually ‘see’ the world and atmospheric particle production,” said Masooma Sarfraz, a doctoral student in Axani’s lab and primary author on the journal article. “For a student like me who has been working on theoretical ideas, this was a perfect opportunity to dive into the experimental side. It also connects beautifully to my current broader research work with particle physics.”

From Dark Matter Research to Spaceflight

The latest CosmicWatch design is well suited for calibrating large-scale detectors. It is currently being used in the NuDot experiment at UD and at the Coherent CAPTAIN-Mills (CCM) dark matter detector in Los Alamos, New Mexico.

Researchers are also developing another version that could measure primary cosmic rays aboard rockets and spacecraft.

Despite its expanding research role, education remains an important part of CosmicWatch. At UD, Axani uses the detector to teach particle, nuclear, and astrophysics. Students assemble the devices themselves, gaining experience with high-speed electronics before using their finished detectors in experiments they design.

Musarate Shams, a doctoral student in the quantum science and engineering program, modified his own CosmicWatch by adding temperature and pressure sensors. His goal was to study cosmic rays in Earth’s upper atmosphere.

In May, the detector traveled aboard a high-altitude balloon to 100,000 feet, near the edge of space. After examining the measurements, Shams was able to show how the flow of cosmic rays from space changes as altitude increases.

“It’s a very cool thing to build something in the lab in a couple of days that’s able to detect these cool particles from hundreds of light-years away,” he said.

Giving Students a Taste of Real Particle Physics

CosmicWatch is also being used outside the University of Delaware. Natasha Holmes, the Ann S. Bowers Associate Professor of Physics at Cornell University, has students in her introductory physics courses build the detectors and conduct experiments with them.

She said that working directly with the technology gives students an experience that feels much closer to professional experimental physics.

“The students seem really excited about doing this thing that is more like what particle physicists and experimental physicists actually do,” she said. “They get to learn some coding with it, and sometimes they break the devices, and then we have to talk to them about being careful with your equipment. It’s very different from a typical physics lab. We’ve had students say they’re doing ‘real science’ after using it.”

A Possible Global Network of Cosmic Ray Detectors

Axani estimates that thousands of CosmicWatch detectors have been built since the first version appeared eight years ago. He hopes that number could eventually grow much larger through a worldwide “citizen science” effort.

Under that idea, people in different parts of the world could measure local muon rates and send their observations to a central location online. Together, those measurements could create a much broader picture of particle activity around the planet.

Axani is also developing a related detector system that could help groups of satellites respond more intelligently to changes in their environment. The technology could allow satellites to communicate with one another about conditions in space. If a solar flare were detected, for example, the system could alert nearby satellites so they could power down when necessary.

What began as an inexpensive educational project has now spread into several areas of advanced physics, something Axani did not originally expect.

“Although it started as an educational program, it’s found a use in a lot of different areas of physics,” Axani said. “It’s pretty cool.”