Despite significant medical advances, spinal cord damage remains one of the most difficult physical injuries to treat. Scarring frequently gets in the way of nerve fiber regrowth, while nerve cells usually cannot regenerate on their own. A possible solution? A fleet of stem cell-infused, injectable nanorobots that can help nerve cells regenerate. The tiny bots are detailed in a study recently published in the journal Nature Materials.

To build their new tools, a team at ETH Zurich in Switzerland engineered microscopic machines that combine living neural progenitor cells (NPCs)—specialized stem cells developed for the spine—with customized nanoparticles. These customized nanoparticles feature two layers—one that is sensitive to magnetic fields and another that translates them into electrical signals.

“We place a reservoir in the center where we trap the cells. Then we inject the nanoparticles and wait for the two components to bind,” Salvador Pané i Vidal, a study co-author and ETH Zurich roboticist, said in a statement.

Each nanorobot is about six micrometers wide, making them smaller than a red blood cell. However, the number of robots required to pull off a procedure is immense. Millions of nanobots are needed during animal trials. Even with such a high number, the initial experimental results are promising. In tests involving mice with severed spinal cords, nerve cells stimulated by the microrobots began reconnecting at the injury site within 28 days. By the end of the trial, the mice displayed major improvements in movement, gait, coordination, and exploratory behavior. 

Significantly more research is required before these nanobots are ready for primetime, but the team hopes to one day begin testing similar devices in humans. Before that, they need to determine the most effective magnetic fields and how long to apply them to patients. In the meantime, the overall design could also be applied to help treat regenerative issues in organs and wounds.

“The reproducible and scalable production of microrobots using our lab-on-a-chip system demonstrates that the platform’s application potential extends beyond basic research,” added Pané i Vidal.

The post Injectable nanorobots may help heal spinal injuries appeared first on Popular Science.

In a groundbreaking review set to reshape public health policies, researchers at the University of Mississippi have presented compelling evidence that ambient air pollution levels deemed safe by current Environmental Protection Agency (EPA) standards may nonetheless pose a significant risk to cardiovascular health. This extensive review, recently published in the scientific journal Environmental Pollution, synthesizes decades of global research, underscoring the urgent need to revisit and potentially lower regulatory thresholds for fine particulate matter, specifically PM2.5.

PM2.5 refers to microscopic particulate matter with a diameter less than 2.5 microns—around 20 times smaller than a human hair—which makes them capable of penetrating deep into the respiratory tract and entering the bloodstream. These particles originate from diverse sources such as vehicular emissions, industrial manufacturing, biomass burning, and dust from agricultural activities. Their diminutive size allows them to circumvent the body’s natural defense mechanisms, reaching vital organs and triggering systemic health effects.

The review meticulously analyzed 95 peer-reviewed studies that addressed cardiovascular impacts related to low-level PM2.5 exposures worldwide. Strikingly, approximately two-thirds of these studies demonstrated significant associations between PM2.5 exposure and adverse cardiovascular outcomes, including heart attacks, strokes, and increased arterial plaque accumulation. Such findings suggest that even concentrations below the EPA’s current allowable limits can compromise cardiovascular function and contribute to disease progression.

One of the most alarming revelations from the review is the heightened vulnerability of specific demographic groups. Older adults, infants, individuals with preexisting heart conditions, socioeconomically disadvantaged communities, and marginalized populations bear a disproportionate burden of the health consequences posed by low-level PM2.5 exposure. The underlying reasons include a combination of biological susceptibility, existing comorbidities, and environmental inequities that result in unequal pollution exposures.

Experts leading the study emphasize that the source of PM2.5 plays a pivotal role in its health impact. Traffic-related pollution, industrial emissions, and rural dust each possess unique chemical compositions and particle characteristics that influence toxicity. For instance, black carbon—a key component of soot prevalent in urban areas—has been linked to respiratory and cardiovascular morbidity. Understanding these nuances is critical for tailoring regulatory actions and mitigation strategies.

Technological advances in air quality monitoring have highlighted the dynamic nature of pollution exposure. Daily fluctuations in PM2.5 concentrations, even within previously considered ‘safe’ ranges, can exacerbate risk. The lack of widespread public awareness regarding these subtleties hampers proactive health protection. Consequently, researchers call for enhanced education campaigns to inform communities about real-time air quality risks and personal protection measures.

Cardiovascular disease remains the leading cause of mortality on a global scale, and these findings carry profound implications for public health. The pathophysiological mechanisms implicate PM2.5 in accelerating atherosclerosis, fostering systemic inflammation, and enhancing thrombogenic potential. These processes collectively escalate the likelihood of acute cardiovascular events. The pervasiveness of PM2.5 exposure across urban, industrial, and rural environments necessitates a broad-reaching response.

Current public health recommendations to mitigate individual risk include monitoring localized air quality indices and adopting practical interventions on high-exposure days. Utilization of high-efficiency particulate air (HEPA) filtration systems within indoor environments, combined with the use of adequately rated masks such as N95 respirators, can substantially reduce personal particulate inhalation. These tools are particularly vital for sensitive populations engaging in outdoor activities during episodes of elevated pollution.

The review underscores the critical interplay between environmental science and clinical health disciplines. Healthcare providers are encouraged to integrate pollution exposure assessments into routine cardiovascular risk evaluations. Furthermore, temporal spikes in air pollution should prompt heightened clinical vigilance among patients with known cardiovascular vulnerabilities.

While treatment modalities for pollution-induced cardiovascular damage remain limited, prevention through regulatory intervention and public engagement is paramount. This study advocates for policy reforms that reflect emerging scientific evidence—ideally, lowering the maximum allowable PM2.5 levels to afford more comprehensive protection for population health. Robust air quality enforcement accompanied by community education initiatives constitutes the frontline defense.

Mississippi’s unique environmental landscape, marked by a blend of rural, industrial, and urban pollution sources, exemplifies the broader challenges in managing fine particulate exposure. Researchers at the University of Mississippi have specifically documented elevated black carbon concentrations across various locations within the state, correlating these findings with increased respiratory admissions. Such regional data, when synthesized with global research, bolster the call for targeted policy improvements.

This collective body of work spotlights the critical need for multi-sectoral collaboration spanning environmental regulation, healthcare, urban planning, and public advocacy. Addressing the insidious cardiovascular risks posed by low-level PM2.5 pollution demands concerted efforts to enhance air quality monitoring infrastructure, refine healthcare response frameworks, and cultivate informed, empowered communities.

Ultimately, the path forward rests on reimagining air quality standards rooted in rigorous health evidence. By recognizing and acting upon the risks associated with fine particulate pollution at even low concentrations, society can better safeguard cardiovascular health and reduce the burden of pollution-related morbidity on a global scale.

Subject of Research: Health impacts of low-level ambient fine particulate matter (PM2.5) exposure and cardiovascular outcomes

Article Title: A systematic review of low-level ambient fine particulate matter (PM2.5) exposures and adverse cardiovascular health outcomes

Web References:

• EPA Air Quality Basics: https://www.epa.gov/pm-pollution/particulate-matter-pm-basics
• EPA Air Pollution and Cardiovascular Disease: https://www.epa.gov/air-research/air-pollution-and-cardiovascular-disease-basics
• WHO Cardiovascular Diseases Overview: https://www.who.int/health-topics/cardiovascular-diseases#tab=tab_1

References:
University of Mississippi Review in Environmental Pollution, DOI: 10.1016/j.envpol.2026.127978

Image Credits: Photo illustration by John McCustion/University Marketing and Communications

Keywords: Air pollution, PM2.5, cardiovascular health, fine particulate matter, environmental toxicology, public health, pollution regulation, black carbon, respiratory health, environmental epidemiology, pollution exposure, air quality monitoring

A groundbreaking study from the University of California, San Francisco (UCSF) has revealed the hidden scientific and industrial strategies employed by Philip Morris Companies Inc. in the creation and marketing of Lunchables, turning what seemed to be a simple children’s convenience food into one of America’s most pervasive ultra-processed food products. This research uncovers how advanced cigarette research, flavor chemistry, and behavioral science were ingeniously adapted to the food industry, reshaping children’s eating habits and fueling public health challenges.

When Philip Morris acquired General Foods in 1985, it gained ownership not just of an existing food company but of an innovative product still in development: Lunchables. This acquisition marked a critical convergence of tobacco industry expertise with food product innovation. The UCSF study, recently published in the American Journal of Public Health, provides the first comprehensive analysis of how this meld of industries engineered ultra-processed foods by applying decades of tobacco research to optimize flavor, texture, and consumer appeal, especially targeting children.

Ultra-processed foods have become a dominant force in the American food landscape, making up nearly two-thirds of caloric intake among U.S. children. These foods are characterized not by their natural ingredients but by complex formulations containing artificial additives and flavor enhancers. Clinical trials consistently demonstrate that such products promote overeating and contribute directly to the rising epidemics of childhood obesity, type 2 diabetes, and metabolic liver diseases. This study thus places Philip Morris’s strategies at the center of an industrial transformation that has long-term public health implications.

Delving into corporate archival documents, including memos and internal strategic reports released during legal processes, the research reveals how tobacco companies like Philip Morris and R.J. Reynolds deliberately ventured into the food industry in the 1980s. These companies owned major food brands such as Nabisco and Del Monte, and their entry into the food sector was not accidental but a carefully crafted business strategy designed to leverage synergies between tobacco and food product development.

Philip Morris’s merger with Kraft General Foods created North America’s largest food conglomerate, facilitating the transfer of proprietary knowledge and experimental techniques developed for cigarette design into food product engineering. This integration allowed for cross-division innovation, particularly in flavor chemistry and packaging technology, maximizing commercial returns by optimizing production efficiency while manipulating sensory experiences in ways that deepen consumer engagement and loyalty—particularly among young consumers.

A key element of the strategy was the concept of “technical synergies.” By adapting shelf-stable packaging technologies originally perfected for tobacco products, the company was able to develop innovative “grab-and-go” meal kits that preserved flavor and texture while appealing immensely to children’s preferences and parental desires for convenience. This packaging also extended product shelf life, thereby reducing costs and enabling rapid nationwide distribution.

Lunchables were particularly designed to tap into children’s behavioral and psychological drives. The product’s segmented packaging encouraged children to interact with their meal—essentially “playing” with food by assembling it according to their preferences—thereby fostering a sense of independence and control. Through vivid branding and familiar processed ingredients, such as Oscar Mayer meats and Kraft cheeses, the product also assuaged parental concerns while embedding itself as a staple in children’s diets across the country.

Intriguingly, when Philip Morris sought to introduce low-fat versions of Lunchables, they adapted neuroscience and behavioral testing techniques originally developed for nicotine research. Tobacco experts well-versed in the neural pathways of flavor perception applied electroencephalography (EEG) and sophisticated sensory tests to optimize the palatability of artificial fats and flavor additives without compromising taste. This crossover exemplifies the complex technological and scientific exchanges that fueled the surging growth of ultra-processed foods.

Laura Schmidt, PhD, the lead author of this study and a professor of medicine at UCSF, explicates that the fundamental difference between ultra-processed and minimally processed foods lies in these additives and flavor engineering technologies. The intricate manipulation of taste and sensory appeal using cigarette technology, she explains, was crucial in creating food products that go beyond mere sustenance to tap into deep neurobehavioral motivators shaping consumer choices—especially in children.

This research was facilitated by the accessibility of Philip Morris’s internal documents housed in the UCSF Industry Documents Library, which offers an unprecedented archive of millions of records across multiple sectors including tobacco, food, chemicals, and fossil fuels. Availability of these records has enabled researchers to reconstruct the corporate strategies behind the rise of ultra-processed foods and their lasting influence on public health.

Facing a wave of litigation and strengthening regulations during the 2000s, tobacco companies gradually divested from their food sector holdings by 2007, refocusing on their core business of cigarette manufacturing. Nevertheless, the ultra-processed food industry, once catalyzed by these tobacco conglomerates, continued its rapid expansion throughout the 21st century, perpetuating a cycle of public health concerns tied to diet-related diseases.

The UCSF study highlights an urgent need to consider the historical and industrial origins of ultra-processed foods when devising public health policies aimed at curbing the rising rates of obesity and metabolic disorders among children. Understanding that these products were engineered with sophisticated neurobehavioral insights borrowed from tobacco science underscores the challenge of addressing their pervasive role in contemporary diets.

By revealing how tobacco companies’ scientific expertise was redirected to engineer enticing food products for children, this research uncovers the hidden industrial forces that have shaped modern American dietary patterns, emphasizing the critical intersection of corporate strategy, neuroscience, and public health.

Subject of Research: Scientific and industrial strategies of tobacco companies applied to ultra-processed food product design, particularly focusing on Lunchables and associated public health impacts.

Article Title: Tobacco Science and Flavor Engineering: How Philip Morris Designed Lunchables to Maximize Children’s Appeal

News Publication Date: June 3, 2026

Web References:
– American Journal of Public Health Article: https://ajph.aphapublications.org/doi/epdf/10.2105/AJPH.2026.308491
– UCSF Industry Documents Library: https://www.industrydocuments.ucsf.edu/food/

References: Internal corporate documents from Philip Morris Companies Inc., legal discovery archives, and neuroscience studies on flavor perception.

Image Credits: Not available

Keywords
Tobacco, Behavioral neuroscience, Social neuroscience, Obesity, Childhood obesity, Children, Type 2 diabetes, Diabetes, Fatty liver disease, Weight gain, Brain

An expert explains.

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An expert explains.

ScienceAlert stories are written, fact-checked, and edited by humans, never generated by AI. Don't miss a story, subscribe here.

A recent cohort study conducted across numerous U.S. households with children sheds light on a critical factor influencing family well-being: the burden of high out-of-pocket medical expenses. This study reveals that such financial strain extends beyond the immediate challenge of covering healthcare costs, potentially undermining the ability of families to meet other essential health-related social needs. These needs encompass access to nutritious food, the capacity to pay essential bills, and securing adequate, quality housing—all foundational elements contributing to both physical and psychological health.

The research underscores a complex and cascading effect where substantial medical expenditures diminish disposable income available for these crucial necessities, exposing families to a heightened risk of adverse health outcomes. This multifaceted relationship highlights the interconnectivity between healthcare costs and social determinants of health, effectively portraying how economic hardship in medical spending can destabilize broader aspects of a household’s life.

By examining data from diverse households, the study articulates a nuanced perspective on how chronic financial pressure from healthcare payments impinges upon the ability of families to maintain food security. Nutrition, a critical pillar of health, becomes compromised when families face choices between procuring medications or purchasing groceries. Such dilemmas can exacerbate existing health conditions or contribute to new health challenges, thereby perpetuating a vicious cycle of poor well-being.

Equally important, the findings draw attention to the impact of medical expenses on a family’s capacity to pay routine bills, including utilities and other fixed costs necessary for sustaining a stable living environment. Disruptions in paying bills not only cause immediate discomfort but can also trigger longer-term economic instability, which is intrinsically linked to stress and mental health disorders.

Furthermore, the study posits that the quality of housing is often deprioritized in the face of mounting medical bills. When forced to allocate substantial funds for health services, households might settle for lower-quality housing or face housing insecurity. Housing inadequacies—such as overcrowding, poor ventilation, or unsafe neighborhoods—are known contributors to significant health disparities, amplifying the social costs of medical financial burdens.

The implications of these findings resonate profoundly within the healthcare policy domain. The study suggests that attempts to curtail high out-of-pocket costs, through policy reform or insurance redesign, could have far-reaching benefits beyond immediate medical affordability. By alleviating financial stress due to healthcare, families might retain or regain their ability to secure other health-promoting resources.

In this context, the study raises important questions about the design and structure of health insurance coverage and the broader social safety net. It indicates the need for more comprehensive approaches that incorporate support for social determinants of health alongside medical care. Such integration could inform future strategies targeting health equity and chronic disease management.

Moreover, it is noteworthy that this relationship between out-of-pocket costs and social needs is not merely correlational but potentially causal through mechanisms related to income allocation and financial decision-making. Families juggling expensive medical bills are more likely to experience trade-offs that adversely affect their health and social stability, evidencing a systemic vulnerability that demands interventions beyond clinical care.

Importantly, the cohort study focuses particularly on households with children, a demographic where the stakes of unmet health-related social needs are exceptionally high. Children’s development and long-term health trajectories are intimately tied to stable nutrition, housing, and economic security. Disruption in any of these domains can have lasting consequences throughout the lifespan.

This comprehensive research also contributes to growing evidence that tackling healthcare costs in isolation cannot fully address health disparities. Instead, it emphasizes a holistic understanding of health economics that encompasses the synergy between medical expenses and social conditions.

For healthcare providers, policymakers, and advocates, these findings underscore the critical role of integrating social support mechanisms with medical treatment plans. Addressing out-of-pocket costs alone, while crucial, must be paired with broader efforts to enhance social needs assistance in order to improve overall population health outcomes.

The evidence from this study invites stakeholders to reconceive health interventions through a multidisciplinary lens, where economic, social, and clinical factors are unified considerations. This paradigm shift is essential for designing effective solutions that mitigate the multifactorial risks posed by healthcare costs on the well-being of vulnerable families.

In summary, this important cohort study enriches our understanding of how high out-of-pocket medical costs can profoundly impair families’ access to essential social supports, risking a cascade of negative health consequences. Its findings advocate for a reformed healthcare system that advances affordability and integrates social determinants to foster healthier communities nationwide.

Subject of Research: Impact of high out-of-pocket medical costs on affordability of health-related social needs in U.S. households with children
Article Title: Not provided
News Publication Date: Not provided
Web References: Not provided
References: (doi:10.1001/jamanetworkopen.2026.16485)
Image Credits: Not provided
Keywords: Health care costs, Out-of-pocket medical expenses, Social determinants of health, Food security, Housing quality, Health disparities, U.S. households with children

It’s four in the morning and you wake from a dream. It wasn’t a nightmare exactly, but it was vivid and unsettling—a circus of imagery in which the other commuters stuck in gridlock beside you were all octopi  or your feet were transformed into a pair of horse hooves while going through airport security. 

Maybe you don’t often remember your dreams but this one, this episode that fused the mundane with the outlandish, it sticks. Even days later, you can still see those tentacles gripping the steering wheels or feel the awkwardness of your gait running to catch your flight. 

It couldn’t have been that joint you smoked before bed, could it? Science says maybe.

How weed effects sleep cycles

Reports of vivid dreams are “very well known” in cannabis and neuroscience research, says Andrew Kesner, assistant professor of psychology at Indiana University in Indianapolis. But “we still don’t really know the neurobiology of dreaming and what sort of features make you remember your dreams better or worse.”

What researchers do know is how consuming weed alters sleep patterns. 

Cannabinoids are found naturally in the brain in a non-psychoactive form called endocannabinoids. Endocannabinoids control our sleep/wake cycle, aka our circadian rhythms, by modulating and maintaining the brain’s biological balance through an abundant receptors neuroscientists call CB1. 

“When people fall asleep, the brain makes its own cannabinoids that increase and decrease throughout the sleep-wake cycle, and throughout the day,” explains Kesner.

Marijuana contains a different form of cannabinoid than the one naturally produced by the brain, THC or tetrahydrocannabinol. THC also works on the brain’s CB1 receptors but, unlike endocannabinoids, it is psychoactive, meaning it makes users feel high by producing feelings like euphoria and paranoia. 

When you smoke weed before bed, the THC added to the brain’s natural endocannabinoids sends the brain’s CB1 receptors into overdrive. And when those CB1 receptors are in overdrive, they change the way you sleep.

Natural sleep in healthy adults begins with a short period of nodding off followed by a stage of “slow-wave” sleep, that deep sleep from which it’s hard to wake someone up. Cycles of lighter sleep punctuated by bouts of REM (rapid eye movement) sleep follow, growing longer and longer throughout the night. 

“REM sleep is classically the time when you’re dreaming,” says Kesner, when “your brain acts like it’s awake but the brain stem paralyzes your body so you can’t act out your dreams.” 

Consuming THC appears to suppress REM sleep: It causes it to arrive later in the sleep cycle and to make up less of the overall percentage of sleep. THC also causes more frequent interruptions to REM sleep. That, says Kesner, may be the origins of its reputation for causing weird dreams. 

“We know if you wake someone up in REM sleep, that’s when they have the highest chance to remember their dreams,” he explains. So, while there’s no evidence that dreams under the influence of THC are any different than THC-free dreams, the ability to remember them more easily may make the sleeper believe they are more bizarre or intense. 

According to one recent study, a dreamer is also likely to feel more rested following a night of vivid dreams, which may be one reason why many people feel smoking a joint or eating a gummy helps them to sleep.

Dreams are slippery suckers

Anything more is hard to say for sure.

“It’s possible that the THC could be making dreams more intense by changing cortical activity [the way the brain functions], making them wonkier and maybe adding some variability to what you’re dreaming about,” Kesner continues. But the huge variability among individuals in both sleep and the effects of THC use makes objectively studying weed-induced dreams “kind of a nightmare”—pun not intended. 

Researchers still don’t even know exactly what dreams are or why they happen—though there’s a good chance that it may be the brain coming up with different learning scenarios, according to Kesner. Someone who plays with puppies all day may, for example, dream that night about being chased by wolves. That way, if it ever happens in real life, the dreamer is better prepared to react to them. 

Whether the weed was smoked or taken in edible form is probably also important; THC immediately affects the brain when smoking while edibles take time for the body to metabolize. One study in which participants reported weird dreams after smoking weed before bedtime, therefore, may have had to do more with the way REM sleep “rebounds,” or immediately returns to longer and more robust natural cycles, when the brain experiences THC withdrawal than with THC’s psychoactive effects. 

It’s well documented, says Kesner, that chronic THC users experience more intense REM sleep after they stop using it. The same might happen in occasional users, whose REM sleep could theoretically become more intense as the acute effects of weed wears off during the night. In other words, you don’t sleep as well while weed’s psychoactive THC is bouncing around your brain but it becomes much more restorative as soon as its effects wear off. 

Ultimately, there probably is no “one-size-fits-all for what cannabis does to sleep or how it affects dreams,” Kesner concludes. As of now, there’s simply not enough data to come to any meaningful verdict. THC or not, dreams are, by their very nature, weird.

In Ask Us Anything, Popular Science answers your most outlandish, mind-burning questions, from the everyday things you’ve always wondered to the bizarre things you never thought to ask. Have something you’ve always wanted to know? Ask us.

The post Weed really does change your dreams appeared first on Popular Science.