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  • New programmable photonic chip can control how fast light moves

    New programmable photonic chip can control how fast light moves

    Researchers at Seoul National University and the University of Seoul have developed a programmable photonic integrated circuit that can slow light whenever needed.

    The team was led by Professors Namkyoo Park and Sunkyu Yu of the Department of Electrical and Computer Engineering at Seoul National University, working with Professor Xianji Piao of the School of Electrical and Computer Engineering at the University of Seoul.

    Slowing Light Could Help Solve a Computing Bottleneck

    The rapid growth of generative AI and large scale AI models has sharply increased the amount of computing power required by data centers and servers. Conventional electronic semiconductors are struggling to keep pace because they consume large amounts of energy and face limits in how quickly they can transmit data.

    These challenges have intensified interest in optical computing, which uses light rather than electrical signals to process information. Optical systems could potentially move data at extremely high speeds while using less power.

    However, light also presents a major challenge. Because it naturally moves at a fixed speed, it is difficult to delay optical signals or temporarily hold them in place. Those capabilities are essential for creating buffers and memory functions in optical computers.

    To address this problem, the researchers designed a programmable photonic circuit that can control both the speed and shape of optical signals. Their approach provides more flexibility over “slow light” than previously proposed methods.

    The study was published in the renowned international journal Advanced Science.

    Why Optical Signals Sometimes Need To Wait

    Photonic integrated circuits are emerging as a promising technology for processing information quickly and efficiently with light. In data centers, optical communication networks, and future computing systems, moving signals rapidly is only part of the challenge.

    Systems must also ensure that different signals arrive at the correct time. In some cases, a light signal must be delayed so it can remain synchronized with other information moving through the system.

    One method for creating these delays relies on coupled-resonator-induced transparency (CRIT), which uses interference among several optical resonators.

    CRIT allows light within a selected frequency range to pass through a device while also reducing the speed at which the optical signal travels.

    • Coupled-resonator-induced transparency (CRIT): An optical phenomenon that selectively transmits and delays light within a specific frequency range through interference among multiple resonators.
    • Optical resonator: A photonic device that confines or circulates light of a specific frequency for a certain period; used in signal delay, filtering, and modulation.

    Fixed Optical Devices Limit Flexibility

    Traditional CRIT devices usually have operating characteristics that become permanent once they are manufactured. This makes it difficult to change how they function after fabrication.

    For example, engineers who want to create a longer signal delay or work with a different frequency range often need to design and manufacture an entirely new photonic device.

    That lack of adaptability increases the complexity of optical communication hardware and data center infrastructure. It can also raise costs and extend development schedules whenever new capabilities are needed.

    The problem is especially important for AI servers and next-generation data centers, where enormous amounts of information must be processed in real time. Fixed optical components have therefore remained a major obstacle to more practical optical computing systems.

    A Programmable Design for Controlling Light

    The research team developed a different strategy by treating two optical states in CRIT systems, known as the bright mode and dark mode, as one unified degree of freedom. The researchers also added two controllable loop couplers.

    Together, these changes created a new design principle for programmable photonic integrated circuits. Resonator arrangements that were previously locked into one configuration after fabrication could instead be adjusted for different purposes.

    Using the new CRIT structure, the researchers showed that the movement of light could be delayed and controlled as needed. They also demonstrated that interference between the bright and dark modes could be handled as a single integrated design parameter.

    This approach greatly expanded the flexibility of photonic resonator circuits that had previously been limited by fixed designs.

    Controlling Delay, Bandwidth, and Signal Shape

    The researchers theoretically demonstrated that the two loop couplers could be used to adjust the bandwidth and shape of the passband. They could also control how long signals were delayed and how efficiently those signals traveled through the circuit.

    This means that both the speed and transmission behavior of optical signals could be reconfigured across entire systems containing multiple resonators, rather than only within a single resonator.

    Numerical simulations also showed that the speed of optical pulses could be adjusted dynamically while the circuit was operating.

    The results indicated that signal delay times could be changed without reducing processing performance. The system could also convert the frequency of light without requiring additional specialized components.

    • Optical pulse: A short burst of light used as a basic unit for transmitting information in optical communication and computing systems.

    Simulations Suggest the Chip Could Be Practical

    The researchers used three-dimensional electromagnetic simulations to test whether the CRIT device could be built on a silicon nitride (Si3N4) photonic integrated circuit platform.

    They also evaluated a range of real-world issues that could affect the device during manufacturing and operation. These included material losses, differences in resonator quality, backscattering, coupling fluctuations, phase errors in the loop couplers, and thermal crosstalk.

    The simulations indicated that the proposed structure could continue to operate reliably under realistic conditions.

    • Silicon nitride (Si3N4) photonic integrated circuit: A low-loss and highly stable waveguide platform widely used for optical signal processing and integrated photonic devices.
    • Thermal crosstalk: A phenomenon in which heat generated in one part of a circuit affects neighboring components, potentially altering device performance.

    One Chip Could Perform Several Optical Functions

    The study introduces a programmable photonic platform that can control both the timing and frequency properties of light signals in real time.

    The design could overcome the limitations of conventional optical delay devices, which typically perform only fixed functions. It also suggests that several important capabilities could eventually be combined within one photonic circuit.

    These functions include signal synchronization, adjustable delay lines, optical buffers, and frequency conversion.

    The same design principles may also be useful beyond CRIT systems. The researchers believe the approach could be applied to a broad range of photonic circuits based on resonators, potentially providing a foundation for more adaptable optical signal processing technologies.

    Potential Benefits for AI and Data Centers

    If the technology is commercialized, a single programmable optical chip could perform several tasks, including controlling signal speed and switching between different functions.

    In that sense, the chip could operate in a way similar to a software-defined system, with its behavior adjusted according to changing needs.

    This flexibility could help data centers and AI servers process information more efficiently while reducing energy consumption.

    Combining several signal processing functions on one chip could also make optical communication equipment and sensor systems smaller and less expensive.

    Over the longer term, the technology could support industries that depend on extremely fast information processing, including autonomous driving, next-generation communications, and quantum technologies.

    Researchers Plan Larger Programmable Photonic Systems

    Professor Namkyoo Park, co-corresponding author of the study from Seoul National University, stated, “This research is significant in that it proposes a new design principle that allows the flow of light within photonic integrated circuits to be reconfigured as needed, greatly enhancing design flexibility. We plan to expand this technology toward large-scale programmable photonic integrated circuits based on silicon photonics and photonic AI technologies.”

    Co-first authors Dr. Seungkyun Park and Ph.D. student Beomjoon Chae, who led the theoretical framework and numerical analysis, added, “Through this study, we realized that reinterpreting conventional photonic resonator physics from a different perspective can serve as a starting point for discovering new functionalities in photonic integrated circuits. We plan to further develop this research toward practical device implementation and experimental validation.”

    Dr. Seungkyun Park is affiliated with the InnoCORE PICORE Center at KAIST and is currently conducting research on photonic AI and quantum optics at the Photonic Systems Laboratory, Seoul National University.

    Ph.D. student Beomjoon Chae is conducting research on programmable photonic integrated circuits at the Intelligent Wave Systems Laboratory, SNU.

    The research received support from the Ministry of Science and ICT through the Innovative Research Center (IRC) program, the Basic Research Laboratory (BRL) program, and the Young Researcher Program.

    Dr. Seungkyun Park also participated in the study with support from the InnoCORE program (PICORE Center).

  • Coffee may help the body fight stress and aging through a hidden cellular switch

    Coffee may help the body fight stress and aging through a hidden cellular switch

    Coffee has repeatedly been associated with longer life and a lower risk of several chronic illnesses. Even so, scientists have not fully understood the biological processes that might explain those benefits.

    New findings from the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) point to one possible answer. Researchers found that certain compounds in coffee may activate NR4A1, a receptor that is becoming increasingly important in studies of aging, stress responses and disease.

    The research, recently published in Nutrients, offers one of the first direct links between coffee compounds and NR4A1. That connection may help explain some of the broad health effects associated with drinking coffee.

    “Coffee has well-known health-promoting properties,” said Dr. Stephen Safe, distinguished professor and Sid Kyle Endowed Chair in Veterinary Toxicology in VMBS’ Department of Veterinary Physiology and Pharmacology. “What we’ve shown is that some of those effects may be linked to how coffee compounds interact with this receptor, which is involved in protecting the body from stress-induced damage.”

    How NR4A1 Helps Protect the Body

    NR4A1 is part of a group of nuclear receptors that help control gene activity when the body is exposed to stress or tissue damage.

    In earlier research, Safe and his collaborators described NR4A1 as a “nutrient sensor,” meaning that it can respond to dietary compounds and contribute to the body’s ability to remain healthy with age.

    “If you damage almost any tissue, NR4A1 responds to bring that damage down,” Safe said. “If you take that receptor away, the damage is worse.”

    Studies have connected NR4A1 with inflammation, metabolism and tissue repair. Each of these processes is closely involved in age-related conditions, including cancer, neurodegenerative disease and metabolic disorders.

    A Possible Mechanism Behind Coffee’s Benefits

    Large observational studies have linked coffee consumption with a reduced risk of Alzheimer’s disease, Parkinson’s disease and metabolic disease. However, those studies have generally shown associations rather than explaining exactly how coffee might produce protective effects.

    Safe and his team proposed that NR4A1 could be one part of that explanation.

    The project involved researchers from across Texas A&M, including Dr. Robert Chapkin, Dr. Roger Norton, Dr. James Cai and Dr. Shoshana Eitan. Their work helped show coffee’s protective effects in neurological models.

    The researchers found that several compounds in coffee can bind to NR4A1 and alter its activity. The most active included polyhydroxy and polyphenolic compounds such as caffeic acid.

    “What we’re saying is that at least part of coffee’s health benefits may come through binding and activating this receptor,” Safe said.

    In laboratory models, these compounds also changed cell behavior in ways associated with disease protection. They reduced cellular damage and slowed the growth of cancer cells.

    When the researchers removed NR4A1 from the cells, those protective effects disappeared. That result provided additional evidence that the receptor helps mediate at least some of coffee’s biological effects.

    Coffee’s Benefits May Extend Beyond Caffeine

    Caffeine is the largest individual component in coffee, but the study indicates that it may not be the main source of the beverage’s protective effects.

    Instead, naturally occurring compounds that are also present in many fruits and vegetables appeared to have a stronger influence on NR4A1.

    “Caffeine binds the receptor, but it doesn’t do much in our models,” Safe said. “The polyhydroxy and polyphenolic compounds are much more active.”

    This finding may help explain why large population studies have linked both caffeinated and decaffeinated coffee with similar health benefits.

    One Pathway Among Many

    Safe cautioned that coffee is chemically complex and probably affects the body through multiple biological routes.

    “There are many receptors and many mechanisms involved,” he said. “What we’re showing is that this could be one of the important pathways.”

    The study was designed to investigate biological mechanisms. It does not establish direct cause and effect in people or prove that drinking coffee prevents disease.

    “There’s still a lot of work to be done,” Safe said. “We’ve made the connection, but we need to better understand how important that connection is.”

    The results support a growing body of research showing that diet, especially plant-based compounds, can influence biological pathways involved in aging and disease.

    Because NR4A1 plays a role in several medical conditions, the findings may also contribute to future drug development. Safe’s team is studying synthetic compounds that target the receptor more effectively than natural dietary substances, with the aim of developing possible treatments for cancer and other diseases.

    The work also highlights the potential importance of routine dietary choices.

    “Coffee is a very complex mixture of compounds,” Safe said. “It’s a very potent combination.”

    What the Findings Mean for Coffee Drinkers

    The research does not change current recommendations for coffee consumption. People can also respond differently depending on their health, sensitivity to caffeine and other individual factors.

    Still, the findings provide scientists with something that has been difficult to identify: a possible biological explanation for coffee’s long-standing association with better health and longevity.

    “I think it helps explain why coffee has the effects that it does,” Safe said. “It’s not just an observation — there’s a mechanism behind it.”

  • Tiny plastics in drinking water may be making dangerous bacteria stronger

    Tiny plastics in drinking water may be making dangerous bacteria stronger

    Nanoplastics are already a concern because people may ingest them directly, but new research points to another possible danger. These tiny plastic particles may also make harmful bacteria more difficult to control.

    In a study published in Water Research, Virginia Tech researcher Jingqiu Liao and an international team found that nanoplastics can interact with environmental microbes in ways that may create indirect risks to human health, especially through drinking water systems.

    “It is very important to better understand the adverse effects of the nanoplastics on human health, and not just in humans but also in the environment, which indirectly influences human health,” said Liao, assistant professor of civil and environmental engineering. “The nanoplastics can make the antimicrobial-resistant pathogens better survive, which could be harmful to the environment and would have public health implications.”

    Nanoplastics May Complicate Water Treatment

    The researchers reported that bacteria exposed to nanoplastics can become more resistant to disinfectants. That could create serious problems for water treatment facilities and distribution networks designed to keep drinking water safe.

    “When the nanoplastics interact with the biofilm and the bacteria inside them, they can strengthen the biofilm and make it more resistant to any kind of measures that are going to keep the water clean,” said Liao, who is also an affiliate with Fralin Life Sciences Institute’s Global Change Center.

    Jingqiu Liao is an assistant professor of civil and environmental engineering. Photo by Peter Means for Virginia Tech.

    Nanoplastics are a smaller category of microplastics. They range from about one to 1,000 nanometers in size and cannot be seen with the naked eye. In this study, the researchers examined how these particles affect the formation of biofilms inside drinking water systems.

    How Bacterial Biofilms Form

    Biofilms are groups of bacteria that attach themselves to surfaces, including the inner walls of water pipes. The microbes produce a protective material around themselves that helps shield the community from environmental threats.

    Biofilms are not always harmful. In some settings, they can help remove undesirable substances. Inside drinking water distribution systems, however, they can pose a risk because some of the bacteria they contain may cause disease.

    The issue is further complicated by bacteriophages, which are viruses that infect bacteria. Before this research, scientists knew relatively little about how nanoplastics might affect the relationships among biofilms, bacteria, and these viruses.

    “The primary process that we were particularly interested in is how the bacteria and the bacteriophages interact with each other during the process when the nanoplastics influence the biofilm as a whole,” said Liao, also an affiliate with the Fralin Life Sciences Institute’s Center for Emerging, Zoonotic, and Arthropod-borne Pathogens.

    Studying Microbes and Antibiotic Resistance

    Liao specializes in microbial ecology and metagenomic analysis. Her previous work has explored how soil contributes to the spread of antibiotic resistance.

    She also recently received a Scaling Scholarship Award through the College of Engineering’s Major Grants Initiative for work connected to the Nature Communications publication, “Differential roles of deterministic and stochastic processes in structuring soil bacterial ecotypes across terrestrial ecosystems.”

    Nanoplastics Trigger Multiple Bacterial Responses

    The researchers studied a biofilm made up of E. coli and Pseudomonas aeruginosa. When the biofilm was exposed to nanoplastics, the bacteria responded in several ways:

    Different bacteria “talk” with one another and release substances that make the biofilm thicker, heavier, and more protective.

    Prophages, which are phages that insert their own genomes (DNA) into the genomes of bacterial hosts, become active. They destroy the bacterial cells they inhabit while producing large numbers of new virus particles.

    The bacteria defend themselves against the prophages by using clustered regularly interspaced short palindromic repeats (CRISPR) of DNA or RNA cells to target the viruses as part of an antiviral defense system.

    An illustration of the three responses from the bacteria when the nanoplastics come into contact with the biofilm. Image courtesy of Jingqiu Liao.

    Tougher Biofilms Could Threaten Water Systems

    The study found that exposure to nanoplastics increased the physical strength of the biofilm and made it more resistant to disinfectants.

    The authors conclude that “the increased mechanical strength of the biofilm and its resistance to the disinfectants highlight a potential challenge for water treatment and distribution systems, as nanoplastics may increase the formation of difficult-to-eradicate biofilms on the surface of some water treatment and distribution systems.”

    These findings suggest that nanoplastics may make it easier for stubborn biofilms to develop on surfaces used in water treatment and delivery, increasing the difficulty of removing them.

    More Research Is Needed

    Liao said additional studies are necessary to identify the molecular processes that drive the responses of complex biofilms containing multiple microbial species.

    She also noted that particle size may play an important role. Microplastics are larger than nanoplastics and could affect interactions between bacteria and phages in different ways.

    “Overall, our findings provide novel insights into the interplay between nanoplastics and bacterium-phage dynamics, highlighting increased microbial risks associated with waterborne nanoplastics,” Liao said.

    Other researchers in the study include the following:

    • Haibo Wang, associate professor, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
    • Hui Chen, associate research fellow, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
    • Chujin Ruan, postdoctoral fellow, environmental microbiology, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
    • Cory Schwarz, postdoctoral fellow, civil and environmental engineering and Rice WaTER Institute, Rice University, Texas
    • Baoyou Shi, professor, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
    • Pedro J.J. Alvarez, professor, civil and environmental engineering and Rice WaTER Institute, Rice University, Texas
    • Pingfeng Yu, postdoctoral fellow, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
  • Scientists tested 39 sweeteners and found unexpected gut effects

    Scientists tested 39 sweeteners and found unexpected gut effects

    Commonly used sweeteners can directly interfere with the growth of bacteria that help support a healthy gut, according to laboratory research from the University of Cambridge.

    The strongest effect appeared when researchers combined isosteviol, a sweetener used by the food and beverage industry, with the antidepressant duloxetine. Together, the two compounds sharply reduced the growth of two important bacterial species associated with digestive health, blood sugar regulation, and immune function.

    The scientists caution that the experiments were conducted in a laboratory rather than in people. More research will therefore be needed to determine whether the bacterial changes lead to meaningful health effects under real-world conditions.

    Sweeteners May Not Be Biologically Inactive

    Sweeteners are found in countless everyday products, including soft drinks, candy, desserts, breakfast cereals, snacks, and some medications. They are commonly promoted as alternatives that provide sweetness with less sugar or fewer calories.

    However, growing evidence has linked sweetener consumption with conditions including type 2 diabetes, obesity, and cancer. These associations do not prove that sweeteners directly cause those diseases, and researchers are still working to understand the biological processes that might explain the connections.

    One possible factor is the gut microbiome, the enormous community of bacteria and other microorganisms living in the digestive system. These microbes help break down food, produce useful compounds, train the immune system, and influence metabolism. Changes in the number or balance of these organisms may affect health throughout the body.

    Despite the widespread use of sweeteners, relatively little research has examined whether they directly affect individual gut bacteria.

    Professor Kiran Patil from the Medical Research Council (MRC) Toxicology Unit at the University of Cambridge said: “Most of what we know about the potential impact of sweeteners on our health comes from animal research or from population studies. While these studies have indicated involvement of the microbiome in mediating the effect of sweeteners, it’s difficult to know how sweeteners act in the body — is it through direct interactions with our gut bacteria?”

    “Answering this is further complicated by the fact that we rarely ever take sweeteners by themselves — we take them with drinks, in snacks, or even in medication to mask bitterness,” added Dr. Sonja Blasche, a lead author of the study, also the MRC Toxicology Unit.

    Testing 39 Sweeteners Against Gut Bacteria

    For the study, published in Molecular Systems Biology, Dr. Blasche and her colleagues investigated how artificial and low-calorie sweeteners influence gut bacteria. They also examined whether those effects change when sweeteners are mixed with substances commonly encountered in foods, drinks, and medicines.

    The team grew 25 bacterial species separately in the laboratory. The selection included bacteria considered beneficial, neutral, or potentially harmful.

    Each species was then exposed to 39 commercially used sweeteners, including both natural and artificial varieties. The researchers monitored how quickly each bacterial culture multiplied and whether its growth slowed or stopped.

    About three-quarters of the sweeteners affected the growth of at least one bacterial species. Several reduced or completely halted the growth of bacteria associated with a healthy digestive system.

    These findings suggest that some sweeteners are not simply inactive substances that pass through the digestive tract without interacting with the organisms living there.

    More Than 100 Unexpected Interactions

    People rarely consume a sweetener in isolation. It may appear alongside caffeine in a beverage, flavoring in a dessert, or an active ingredient in a medication.

    To recreate some of that complexity, the researchers paired the sweeteners with substances including caffeine, vanillin (vanilla extract), advantame (an artificial sweetener), and eight commonly used drugs.

    The team identified more than 100 cases in which a sweetener’s effect changed when another compound was present. The combined effects became stronger in 34 cases and weaker in 68 cases.

    This means that the impact of a particular sweetener may depend partly on what else is consumed at the same time.

    Antidepressant Combination Stood Out

    The most dramatic result involved isosteviol and duloxetine, an antidepressant prescribed to treat depression, anxiety, and certain types of chronic pain.

    When used together, the compounds strongly suppressed Roseburia intestinalis and Parabacteroides merdae. Both species are considered important members of the gut microbiome and have been linked to digestive health and metabolic regulation.

    Duloxetine is widely used. More than 4.2 million patients in the US received prescriptions for the drug in 2023.

    Studying bacteria one species at a time can reveal direct effects, but the human gut is a crowded ecosystem in which microbes constantly interact. To better reflect those conditions, the scientists constructed a simplified microbial community containing all 25 bacterial species.

    They allowed the community to develop and then exposed it to different combinations of sweeteners and drugs. The team tracked which species became more abundant, which declined, and whether the community retained its overall variety.

    Gut Microbial Diversity Declined

    The combination of isosteviol and duloxetine reduced microbial diversity within the synthetic community. Greater diversity is generally considered a feature of a resilient and healthy gut microbiome, although the ideal microbial composition can vary between individuals.

    The combination also changed the community’s internal balance by allowing some bacterial species to flourish while others declined.

    Additional experiments suggested that these changes increased toxicity toward certain host cells. They also disrupted the activity of other cells involved in inflammation and immune responses.

    These results raise the possibility that interactions between sweeteners, medications, and microbes could influence more than digestion alone. However, the simplified laboratory system cannot fully reproduce the complexity of the human body.

    Dr. Blasche said: “Sweeteners are often marketed as metabolically neutral, but our study challenges this idea. We found that they can directly affect gut bacteria, particularly when mixed with other compounds such as medication and food additives. These common combinations could have unintended effects on our gut microbiome.”

    Human Studies Are Still Needed

    The researchers emphasize that the findings should not be interpreted as proof that sweeteners or the tested combinations cause harm in people.

    The experiments involved bacteria and cell models under controlled laboratory conditions. In the human digestive system, sweeteners may be absorbed, chemically altered, diluted, or broken down before reaching particular microbes. Diet, genetics, medication use, and the existing composition of a person’s microbiome could also change the outcome.

    Future studies will need to determine whether similar interactions occur in humans, what doses would be required, and whether any microbial changes produce measurable effects on health.

    Professor Patil, the study’s senior author, added: “Our study suggests that artificial sweeteners don’t just pass through the body passively — they can interact with gut microbes, and these effects can be amplified or altered by other substances like medications. These findings can help guide new studies towards understanding how sweeteners might influence health in unexpected ways.”

    The research was funded by the European Union’s Horizon 2020 program and the UK Medical Research Council.

  • Chewing bubble gum after beetroot may help lower blood pressure

    Chewing bubble gum after beetroot may help lower blood pressure

    Researchers at King’s College London have uncovered an unexpected connection between chewing sugary gum after eating nitrate-rich vegetables and a temporary reduction in blood pressure. The findings suggest that, under specific conditions, sugary chewing gum can help the body make better use of dietary nitrate found in foods such as beetroot, spinach, and kale.

    Nitrate naturally accumulates in vegetables from the soil, but it does not benefit the body until bacteria in the mouth convert it into nitrite. Nitrite helps relax and widen blood vessels, improving blood flow and contributing to lower blood pressure.

    How Mouth Acidity Affects Nitrate Conversion

    Scientists have long known that oral bacteria are essential for converting nitrate into nitrite. Because this process limits how much nitrate the body can use, researchers have been searching for ways to make the conversion more efficient.

    One possibility is that increasing the acidity of saliva could speed up this chemical reaction. To investigate, the research team tested whether chewing sugar-containing gum, which lowers the pH inside the mouth, would increase nitrite production.

    Dr. Andrew Webb, Clinical Senior Lecturer in the School of Cardiovascular & Metabolic Medicine & Sciences, King’s College London, said: “Whether and how the acidity of the saliva in the mouth impacts the conversion of the inactive nitrate, to the more active nitrite, is a fundamental question, as it impacts a range of important physiological functions including blood pressure. However, this process has not been studied much.

    “While most research suggests that increasing acidity inhibits the conversion of nitrate, this has never been investigated in the whole body, over several hours.

    “Incidentally, we previously found that combining grapefruit juice with beetroot juice decreased the acidity of the saliva and inhibited the conversion of nitrate to nitrite in the saliva. So, we wanted to formally test whether doing the opposite – increasing the acidity of the saliva – would enhance the conversion of nitrate to nitrite.”

    Beetroot Juice and Chewing Gum Study

    Healthy volunteers took part in a crossover study in which they drank a shot of beetroot juice before chewing either sugar-containing (Hubba Bubba® bubble) gum or sugar-free (Wrigley’s Extra®) gum for three to six hours. Throughout the experiment, researchers collected blood and saliva samples and monitored blood pressure. At least one week later, each participant returned to repeat the study using the other type of gum.

    Compared with the sugar-free gum, chewing Hubba Bubba significantly increased saliva acidity, producing a 1.4 point drop in pH. Participants also showed a 45% increase in nitrite levels in the mouth and a 25% increase in nitrite circulating throughout the body.

    The sugary gum group also experienced a measurable reduction in blood pressure. Systolic blood pressure (when the heart pushes blood out) fell by nearly 3 mmHg, while diastolic blood pressure (when the heart relaxes between beats) dropped by almost 2 mmHg compared with chewing sugar-free gum.

    Not a Blood Pressure Treatment

    The researchers emphasize that these findings should not be interpreted as a recommendation to chew sugary gum as a way to control blood pressure. The effects were temporary, and regular consumption of sugary products carries well known risks for dental and overall metabolic health.

    However, the discovery could prove useful for athletes, many of whom already consume beetroot because dietary nitrate has been shown to support exercise performance.

    Dr. Webb added: “The effects were only short-term, lasting several hours, and long-term use of sugar-containing products would not be recommended for dental health. Nonetheless, the classic culinary tradition of following a starter and a main course, especially if they contain nitrate-rich salad leaves and vegetables, with a sweet dessert – which could be fruit – may temporarily increase blood pressure-lowering and exercise enhancement.

    “We also suggest that sugary chewing gum will have a greater effect compared to drinking sugary drinks, as it stays in the mouth for a longer period of time.”

    Future Research Could Benefit Athletes

    Co-author Dr. Charlotte Mills, University of Reading, explained that the findings point to new ways of improving how the body processes nitrate without relying on long-term sugar consumption.

    “The bacteria that live in our mouths play a critical role in converting nitrate from foods such as beetroot into beneficial compounds that help relax blood vessels and lower blood pressure. Our findings suggest that the presence of sugar may create a more favorable environment for this process.

    “We are certainly not suggesting that people should start chewing sugary gum regularly. Frequent sugar consumption is harmful for dental health and is also detrimental to cardiometabolic health when consumed in excess. Instead, our findings provide a proof of concept that we may be able to improve how the body processes dietary nitrate, and future research should focus on developing tooth-friendly, metabolically sound approaches that achieve the same effect.

    “The challenge now is to identify alternative strategies that are both effective and appropriate for long-term use.

    “Because dietary nitrate is already a recognized sports supplement, there is potential to optimize how athletes use it. If we can enhance nitrate conversion, we may be able to improve the physiological benefits that athletes obtain from nitrate-rich foods.

    “We found that something as simple as the type of chewing gum used alongside beetroot juice can influence how effectively the body converts dietary nitrate into compounds that help lower blood pressure.”

    The research team now plans to conduct a larger study involving athletes to further examine how sugary chewing gum affects nitrate metabolism, blood pressure, and exercise performance.

    The findings were published in the British Journal of Clinical Pharmacology.

  • Alan Turing’s biggest AI assumption may have been wrong

    Alan Turing’s biggest AI assumption may have been wrong

    Alan Turing’s famous ideas about artificial intelligence may have sent AI research down the wrong path for the past 75 years, according to prominent computer scientist Peter J. Denning.

    In his new book, Turing’s Mistake: Escaping the Yoke of Unintelligent Machines, Denning argues that two foundational assumptions made by Turing in 1950 continue to shape AI research today. The first is that intelligence can exist independently of a physical body and therefore be recreated in computer software. The second is that a machine can demonstrate intelligence by successfully imitating a human in conversation, an idea that later became known as the Turing test.

    “These two claims have shaped much of AI research and development,” Denning writes. “My premise is that our acquiescence to these claims has led to the AI mess in which we find ourselves today.”

    Denning argues that pursuing artificial general intelligence (AGI), or machines with human level intelligence, is unlikely to succeed. Instead, he warns, the technologies society is building could introduce significant new risks.

    The Tacit Knowledge Problem

    At the heart of Denning’s argument is the idea of tacit knowledge, the vast amount of human understanding that cannot easily be put into words or represented in a form that computers can process.

    He says machine learning cannot capture five major categories of tacit knowledge: common sense, everyday interactions with people and the environment, emotions and perception, practical performance skills, and the social and historical knowledge embedded in culture.

    Researchers have long attempted to organize common sense into databases. One of the best known efforts was Douglas Lenat’s Cyc project, which began in the 1980s with the goal of creating an extensive collection of common sense facts. After four decades of work, the project contained roughly 25 million entries.

    “Yet even this treasury could not add up to a background of common sense sufficient to make expert systems smart enough to be experts,” Denning notes. “Cyc validated that much of the knowledge that makes people experts cannot be articulated as propositions.”

    Denning believes practical skills present an even greater challenge.

    “Our performance skills in thousands of domains cannot be communicated to machines,” he explains. “Whereas descriptions of skillful outcomes (‘know what’) can often be represented as bits and stored in a machine, we do not know how to encode the embodied knowledge for skillful performance (‘know how’).”

    He points to accomplished musicians as an example.

    “A virtuoso violinist can play beautiful music yet cannot describe to an acolyte how to produce it.

    “Even if a robot could observe and imitate skilled humans, having no biological body, a robot cannot grasp how the musician feels when playing beautiful music or how an audience feels when hearing it.”

    Denning also includes intuition, gut feelings, imagination, and spontaneous creativity among the forms of tacit knowledge that remain beyond the reach of machines.

    Why Human Knowledge Resists Encoding

    Denning argues that all of these limitations stem from what he calls the “representation problem.”

    Computers can only perform calculations using data and instructions that have been encoded into physical forms they can recognize and process. Tacit knowledge, however, does not naturally fit into that framework.

    “Behind every word is a deep well of tacit knowledge that gives it meaning,” Denning says. “Words are but symbolic representations of meanings, not the meanings themselves. Commonly used Large Language Models, such as ChatGPT, Claude and Gemini only manipulate words, they cannot know or understand the meaning of what they are saying.”

    According to Denning, this creates a fundamental divide. Because scientists still cannot fully explain how tacit knowledge works in humans, they also cannot translate it into a form machines can use.

    “How we host tacit knowledge is largely a mystery,” Denning admits. “All we know is that it is embodied. We have no idea what we might observe and measure in our bodies to reveal it.”

    Context and Culture Shape Intelligence

    Denning also argues that intelligence depends heavily on context, the surrounding circumstances that give words, actions, and decisions their meaning.

    Context allows people to recognize sarcasm, humor, sincerity, and emotion. It helps determine when to be diplomatic, when to joke, and how to interpret countless social cues.

    “When you inquire into where an assumption of the current context came from, you discover it rests on previous conversations from previous contexts. Each of those in turn rests on further previous conversations and their contexts. This pattern is endless and fractal,” Denning explains.

    Culture presents another major obstacle for AI.

    Denning describes culture as encompassing values, norms, judgments, history, communities, moods, and even relationships involving power and care.

    “Human conversations are imbued with background assumptions that give meaning and relevance to the words being used,” Denning explains.

    “Scaling up LLMs with ever larger neural networks will not enable them to acquire the embodied human knowledge we call culture. LLMs will not attain the objective of the Turing test: to demonstrate machine thought indistinguishable from human thought.”

    AI Safety and the Limits of Human Understanding

    Denning concludes that humans and AI systems may ultimately develop different forms of tacit knowledge that neither can fully understand.

    “Machines cannot read our tacit knowledge and we cannot read theirs,” he writes. “We are aliens across an uncrossable divide.”

    He argues this gap raises serious concerns about AI safety. If machines cannot interpret the unspoken context behind human intentions, reliably aligning advanced AI systems with human goals may prove impossible.

    “Through AI automation, agentic networks of machines are likely to develop their own machine intelligence that does not reach the level of human general intelligence but is still quite capable of creating severe problems for humans. This threat is a greater than a take-over by superintelligent machines,” he explains.

    “Machine intelligence has different concerns from us and does not appear to care about us. Its ways of thinking and problem-solving look alien to us. We do not yet know how to live safely with these machines.

    “Pulling back from an AI automation singularity will demand much from us. We start by accepting that the familiar culture is fading away as intelligent machines appear in our society and we do not know what is coming. We decline to think like machines or be subservient to machines. We refuse to submit to a yoke imposed by low-intelligence machines. Most importantly, we reassert our humanity, declare once again what makes us different from machines, and celebrate those differences.”

  • Scientists discovered the brain doesn’t make decisions the way we thought

    Scientists discovered the brain doesn’t make decisions the way we thought

    Scientists at the University of Illinois Urbana Champaign have uncovered evidence that could reshape how researchers think about both the brain and artificial intelligence. Their findings suggest that decision making begins much earlier in the brain than traditional theories propose, offering fresh ideas for designing future AI systems that are more capable and far more energy efficient.

    Led by electrical and computer engineering professor Yurii Vlasov at The Grainger College of Engineering, the research was published in Proceedings of the National Academy of Science (PNAS). The study points to an unexpected role for early sensory brain regions in decision making, challenging the long accepted view that decisions emerge only after information moves through a strict hierarchy of brain regions.

    Rethinking How the Brain Makes Decisions

    The human brain is widely regarded as the most complex structure in the known universe. Scientists still do not fully understand how it works, which is why reverse engineering the brain was identified by the National Academy of Engineering in 2008 as one of the 14 grand challenges for engineering in the 21st century.

    For decades, many artificial intelligence systems, including convolutional neural networks, have been inspired by the idea that the brain processes information in a one way sequence. According to this traditional model, sensory information travels upward through increasingly complex brain regions until it reaches the frontal cortex, where decisions are made.

    Vlasov and other researchers have increasingly questioned whether that picture is complete.

    Instead, they are exploring a model based on natural intelligence, which has been refined through evolution over hundreds of millions of years. In this framework, the brain does not rely only on a step by step flow of information. Decision making also depends on interconnected feedback loops that allow information to move in both directions between brain regions.

    Because biological intelligence performs remarkably complex tasks while using far less energy than today’s AI systems, understanding this architecture could help guide the development of future artificial intelligence.

    “We want to learn from a billion years of evolution,” Vlasov said. “How is that biological intelligence organized architecturally? Can we learn from the architectural side of the brain and emulate that to make AI more effective, less power hungry, and more intelligent than it currently is? In the level of decision-making, that’s where current AI is lacking.”

    Early Brain Regions Show Decision Making Activity

    To investigate how these processes work, the research team focused on the brain’s earliest stages of sensing and perception.

    The scientists recorded neural activity in mice as they navigated a virtual reality corridor and made perceptual decisions. They found evidence of decision related activity in the primary somatosensory cortex (S1), one of the brain’s earliest sensory processing areas.

    Rather than simply passing information forward, S1 appeared to be influenced by higher brain regions through feedback loops. This top down regulation suggests that decision making involves continuous communication across multiple brain areas instead of a simple one direction flow of information.

    “The neural code of the brain is still mostly an unknown language,” Vlasov said. “But this systems-level understanding can be viewed as a potential impact on how more efficient artificial neural networks can be built — how the next generation of AI can be thought through. Maybe with these analogies that we learn from real brains, we can improve AI further.”

    What the Findings Could Mean for Future AI

    The researchers emphasize that the study does not provide a blueprint for building better artificial intelligence. Instead, it offers new insights into how the brain organizes decision making that could eventually inspire future AI architectures.

    Next, Vlasov and his team plan to investigate the timing of these brain signals in greater detail. They also intend to develop new technologies for measuring neural activity to better understand how feedback loops emerge and coordinate different levels of brain processing.

    “By looking at the fast temporal dynamics of neural activity, maybe we can understand better how these feedback loops are engaged in making decisions,” Vlasov said. “Maybe that’s the approach that potentially uncovers these currently unknown mechanisms — how these feedback loops are organized dynamically and how they form and shape different levels of processing. Maybe that can be implemented in new architectures for AI.”

  • Why are healthy young non-smokers developing lung cancer?

    Why are healthy young non-smokers developing lung cancer?

    A diet packed with fruits, vegetables, and whole grains is widely considered one of the best ways to support overall health and reduce the risk of many diseases, including cancer.

    But new research from the USC Norris Comprehensive Cancer Center, part of Keck Medicine of USC, suggests an unexpected possibility. Findings presented at the annual meeting of the American Association for Cancer Research indicate that younger Americans under age 50 who have never smoked and consume more of these healthy foods than average may face a higher risk of developing lung cancer.

    “Our research shows that younger non-smokers who eat a higher quantity of healthy foods than the general population are more likely to develop lung cancer,” said Jorge Nieva, MD, a medical oncologist and lung cancer specialist with USC Norris and lead investigator of the study. “These counter-intuitive findings raise important questions about an unknown environmental risk factor for lung cancer related to otherwise beneficial food that needs to be addressed.”

    Researchers Suspect Pesticide Exposure May Play a Role

    The researchers emphasize that the foods themselves are not believed to be the problem. Instead, they suspect pesticide exposure could help explain the surprising pattern.

    According to Nieva, commercially grown (non-organic) fruits, vegetables, and whole grains generally contain higher levels of pesticide residues than dairy products, meat, and many processed foods. He also pointed to previous research showing that agricultural workers with long term pesticide exposure experience higher rates of lung cancer, adding support to the hypothesis.

    The study also found that women under 50 who have never smoked develop lung cancer more often than men in the same age group. Women in the study also tended to eat more fruits, vegetables, and whole grains than their male counterparts.

    Rising Lung Cancer Cases in Young Non-Smokers

    Lung cancer has traditionally been associated with older adults, smokers, and men. The average age at diagnosis is 71.

    Although smoking rates have steadily declined since the mid 1980s, helping reduce lung cancer cases overall in the United States, one group has not followed that trend. Lung cancer has become more common among non-smokers age 50 and younger, particularly women, who are now more likely than men in the same age group to develop the disease.

    To better understand why, researchers launched the Epidemiology of Young Lung Cancer Project. The study included 187 people who had been diagnosed with lung cancer by age 50. Participants provided information about their diet, smoking history, demographics, and cancer diagnosis.

    Most had never smoked and were diagnosed with a form of lung cancer that differs biologically from the type typically caused by tobacco use. A 2021 study from the Epidemiology of Young Lung Cancer Project, the Genomics of Young Lung Cancer Project, also found that lung cancers diagnosed in people younger than 40 represent distinct subtypes compared with those seen in older adults.

    Healthier Diets Were Common Among Patients

    Researchers compared participants’ diets with those of the general U.S. population using the Healthy Eating Index (HEI), a measure of overall diet quality scored from 1 to 100.

    The young non-smoking lung cancer patients had an average HEI score of 65, compared with the national average of 57. Women in the study generally scored higher than men.

    Participants also reported eating more fruits, vegetables, and whole grains than the average American. On average, they consumed 4.3 daily servings of dark green vegetables and legumes and 3.9 servings of whole grains. By comparison, the typical U.S. adult consumes 3.6 servings of dark green vegetables and legumes and 2.6 servings of whole grains each day.

    More Studies Are Needed

    Nieva stressed that the proposed connection between pesticide exposure and lung cancer remains unproven and requires additional investigation, especially among younger adults and women.

    The researchers did not directly measure pesticide levels in individual foods eaten by participants. Instead, they estimated exposure using previously published data on average pesticide residues found in food categories such as fruits, vegetables, and grains.

    The next phase of the research will involve measuring pesticide levels directly in patients’ blood or urine samples. That work could help determine whether certain pesticides are more strongly associated with lung cancer risk than others.

    “This work represents a critical step toward identifying modifiable environmental factors that may contribute to lung cancer in young adults,” said Nieva. “Our hope is that these insights can guide both public health recommendations and future investigation into lung cancer prevention.”

    The research was supported by the Addario Lung Cancer Medical Institute, a nonprofit organization dedicated to advancing lung cancer research and care, along with AstraZeneca, the Beth Longwell Foundation, Genentech, GO2 for Lung Cancer, and Upstage Lung Cancer.

    Additional funding came from the National Institutes of Health through grant number R25CA225513 and the National Cancer Institute through grant number P30CA014089.

  • Common blood pressure drug could make cancer therapy far more powerful

    Common blood pressure drug could make cancer therapy far more powerful

    A medication that has long been used to treat high blood pressure could also help make an important class of cancer drugs much more effective, according to new research from Dartmouth Cancer Center (DCC). The study found that the FDA approved drug telmisartan significantly boosted the cancer killing activity of the targeted therapy olaparib, raising the possibility that more patients could benefit from the treatment. The findings were published in The Journal for ImmunoTherapy of Cancer.

    “This study shows that a common, safe, tolerable, convenient, and inexpensive drug may significantly improve how well an important class of cancer therapies works,” said Tyler J. Curiel, MD, MPH, FACP, the study’s senior and lead author.

    Making PARP Inhibitors Work for More Patients

    Olaparib belongs to a group of targeted cancer drugs known as PARP inhibitors. These medicines work by taking advantage of defects in the way certain cancer cells repair damaged DNA. They are especially effective against tumors with problems in homologous recombination DNA damage repair, including cancers linked to BRCA gene mutations.

    Many cancers, however, do not have those DNA repair defects, which means PARP inhibitors are not effective for a large number of patients. Even when the drugs initially work, tumors often become resistant over time.

    The Dartmouth team found that telmisartan can make tumors more sensitive to PARP inhibitors, even if they do not have the DNA repair weaknesses that these drugs typically rely on.

    Stronger Immune Response Against Tumors

    In preclinical experiments, combining telmisartan with olaparib increased DNA damage inside cancer cells while also activating important immune defenses. The treatment combination boosted production of type I interferons, signaling molecules that help the immune system identify and attack cancer.

    “This immune activation appears to be a key reason the combination works so well,” Curiel said.

    A Unique Effect Among Blood Pressure Medications

    Telmisartan is part of the angiotensin II receptor blocker (ARB) family of drugs, which are widely prescribed to treat hypertension. Researchers compared telmisartan with other ARBs and found that its cancer enhancing effects were unique within the class.

    The drug also lowered levels of PD-L1 inside tumor cells. PD-L1 is a protein that many cancers use to avoid detection by the immune system, making this additional effect another potential advantage.

    “Telmisartan has several distinct anticancer effects that, together with targeted therapy, could make tumors more responsive to distinct types of treatments,” Curiel said. “We showed the improved efficacy with PARP inhibitors in this study, but we also have good data showing that telmisartan improves efficacy of distinct chemotherapy classes and immunotherapies in many other cancer types through related mechanisms.”

    Early Clinical Trials Are Already Underway

    Because telmisartan is taken by mouth, has an established safety record, and is well tolerated even by people without hypertension, researchers believe it is well suited for rapid testing in cancer patients. Curiel and colleagues at DCC have already launched two clinical trials to evaluate the combination.

    One study is testing telmisartan with olaparib in men with metastatic, castration-resistant prostate cancer. According to Curiel, the first participant experienced an exceptional response to treatment. A second trial recently enrolled its first patient with platinum-resistant ovarian cancer.

    “We are encouraged by what we are seeing so far,” Curiel said. “Our goal is to determine whether this combination approach can help more patients benefit from greater effectiveness of PARP inhibitors and other cancer treatment classes and potentially overcome resistance to these drugs.”

    Support from the Guyre fund and Gmelich fund at DCC played a key role in completing the research and launching the clinical trials.

  • Scientists discover the one nutrient beneficial parasites can’t live without

    Scientists discover the one nutrient beneficial parasites can’t live without

    Intestinal worms may help reduce inflammation, but new research suggests they can only do so when they have enough dietary fiber to thrive. Without sufficient fiber, these worms enter a hibernation-like state and lose their ability to provide anti-inflammatory benefits.

    The findings, published in Nature Communications, come from parasitologists at the Biology Centre of the Czech Academy of Sciences.

    Why Scientists Are Studying Intestinal Worms

    For most of human history, intestinal parasites were a normal part of the digestive system. In industrialized countries, however, they have become far less common because of improved hygiene and modern medicine. During that same period, autoimmune disorders and inflammatory bowel diseases have become increasingly common.

    This trend prompted researchers about two decades ago to investigate whether certain intestinal worms could be used to treat inflammatory conditions. The approach, known as helminth therapy, has shown promise, but its results have been inconsistent.

    “However, the results of helminth therapy have been inconsistent — sometimes the worms suppress inflammation, sometimes they do not. That’s why we focused on factors that may influence their effects in the gut,” says Kateřina Jirků from the Institute of Parasitology, Biology Centre CAS.

    The team’s research pointed to one major factor: the amount of dietary fiber in the host’s diet.

    How Fiber Changes Worm Behavior

    To better understand the connection, the researchers examined how an intestinal parasite responds to different levels of dietary fiber. They used the rat tapeworm Hymenolepis diminuta, a non-pathogenic species commonly used to study interactions among parasites, gut microorganisms, and the immune system because of its known anti-inflammatory properties.

    Their experiments revealed a striking difference between fiber-rich and fiber-poor diets.

    “We found that when the diet contains a high proportion of structural fiber, the tapeworm is not only in excellent condition but is also able to induce an anti-inflammatory response in the host. When fiber is lacking, the worm enters an energy-saving state resembling hibernation in mammals, and its anti-inflammatory effect disappears,” explains Jirků.

    When the animals consumed a low-fiber diet, the tapeworms were several times smaller, never reached sexual maturity, and failed to produce eggs. Genetic testing also showed widespread shifts in gene expression affecting the worms’ development, metabolism, and reproduction.

    Fiber Reshapes the Gut Microbiome

    The researchers also found that dietary fiber transformed the host’s gut microbiome.

    A fiber-rich diet encouraged the growth of bacteria associated with a healthy intestinal environment. In contrast, a Western-style diet reduced microbial diversity and allowed bacteria linked to dysbiosis to become more abundant. These microbial changes were mirrored by differences in the host’s immune response.

    According to the researchers, the study highlights how strongly diet influences the entire gut ecosystem, from parasites and microbes to the immune system itself.

    Health organizations generally recommend that adults consume about 25 to 30 grams of fiber each day, yet average intake across many Western countries falls below that level. Traditional populations, by comparison, are estimated to consume between 80 and 120 grams of fiber daily.

    Previous research has shown that too little dietary fiber can weaken the gut microbiome, which plays an important role not only in digestive health but also in immune function, brain health, and mental well-being. An unhealthy microbial balance has been associated with a higher risk of allergies, depression, anxiety, and neurodegenerative diseases, including Alzheimer’s disease.