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Comment by Dr. Krishna Kumari Challa on Friday

The AI breakthrough that uses almost no power to create images

From creating art and writing code to drafting emails and designing new drugs, generative AI tools are becoming increasingly indispensable for both business and personal use. As demand increases, they will require even more computing power, memory and, therefore, energy. That's got scientists looking for ways to reduce their energy consumption.

In a paper published in the journal Nature, researchers describe the development of an AI image generator that consumes almost no power.

AI image generators use a process called diffusion to generate images from text. First, they are trained on a large dataset of images and repeatedly add a statistical noise, a kind of digital static, until the image has disappeared.

Then, when you give AI a prompt such as "create an image of a house," it starts with a screen full of static and then reverses the process, gradually removing the noise until the image appears. If you want to perform large-scale tasks, such as creating hundreds of millions of images, this process is slow and energy intensive.

Shiqi Chen et al, Optical generative models, Nature (2025). DOI: 10.1038/s41586-025-09446-5

Daniel Brunner, Machine-learning model generates images using light, Nature (2025). DOI: 10.1038/d41586-025-02523-9

Comment by Dr. Krishna Kumari Challa on Friday

Placebo pain relief works differently across the human body

Researchers have used placebo pain relief to uncover a map-like system in the brainstem that controls pain differently depending on where it's felt in the body. The findings may pave the way for safer, more targeted treatments for chronic pain that don't rely on opioids.

Like a highway, the brainstem connects the brain to the spinal cord and manages all signals going to and from the brain. It produces and releases nearly all the neurochemicals needed for thinking, survival and sensing.

Published in Science, the study used 7-Tesla functional magnetic resonance imaging (fMRI)—one of the most powerful brain scanners available—to pinpoint how two key brainstem regions manage pain through placebo effects. 

Researchers exposed 93 healthy participants to heat pain on different body parts and applied a placebo pain-relief cream while secretly lowering the temperature, conditioning them to believe the cream was alleviating their pain.

The temperature used was individually adjusted to be moderately painful as perceived by each participant. Researchers used a self-report scale, where 0 was no pain and 100 was the worst pain imaginable, and sought a temperature between 40 and 50 for each participant.

Later, the same pain stimulus was applied to the placebo-treated area as well as a separate untreated area for comparison. Up to 61% of participants still reported less pain in the area where the placebo cream was originally applied, typical of a true placebo response.

They  found that upper parts of the brainstem were more active when relieving facial pain, while lower regions were engaged for arm or leg pain.

Two key brainstem regions are involved in this process: the periaqueductal gray (PAG) and the rostral ventromedial medulla (RVM). These areas showed distinct patterns of activity depending on where pain relief was directed, with the upper parts of the PAG and RVM more active for facial pain, while lower parts were more active for arm or leg pain.

The brain has a built-in system to control pain in specific areas. It's not just turning pain off everywhere; but working in a highly coordinated, anatomically precise system.

Understanding which brainstem areas are linked to different parts of the body may open new avenues for developing non-invasive therapies that reduce pain without widespread side effects.

The study also challenges long-held assumptions about how placebo pain relief works. Instead of relying on the brain's opioid system, experts say a different part of the brainstem—the lateral PAG—is not only responsible but works without using opioids and could instead be linked to cannabinoid activity.

Opioid-based pain relief typically activates central areas of the brain and can affect the whole body, whereas the cannabinoid circuit that they identified now appears to operate in more targeted regions of the brainstem.

Knowing exactly where pain relief is happening in the brain means we can target that area or assess whether a drug is working in the right place.

Lewis S. Crawford et al, Somatotopic organization of brainstem analgesic circuitry, Science (2025). DOI: 10.1126/science.adu8846

Comment by Dr. Krishna Kumari Challa on Friday

Inflammation may explain why women with no standard modifiable risk factors have heart attacks and strokes

Several people ask me this question: Why do people who lead very healthy lives get heart attacks and strokes?

Yes why?

Cardiologists have long known that up to half of all heart attacks and strokes occur among apparently healthy individuals who do not smoke and do not have high blood pressure, high cholesterol, or diabetes, the "standard modifiable risk factors" which doctors often call "SMuRFs."

How to identify risk among the "SMuRF-Less" has been an elusive goal in preventive cardiology, particularly in women who are often under-diagnosed and under-treated.

A new study now has found hsCRP—a marker of inflammation—can help identify women who are at risk but are missed by current screening algorithms.

Results were presented at a late-breaking clinical science session at the European Society of Cardiology Congress (ESC) and simultaneously published in The European Heart Journal.

Women who suffer from heart attacks and strokes yet have no standard modifiable risk factors are not identified by the risk equations doctors use in daily practice.

Yet the new data clearly shows that apparently healthy women who are inflamed are at substantial lifetime risk. Medical professionals should be identifying these women in their 40s, at a time when they can initiate preventive care, not wait for the disease to establish itself in their 70s when it is often too late to make a real difference.

As part of the study, researchers studied 12,530 initially healthy women with no standard modifiable risk factors who had the inflammatory biomarker hsCRP measured at study entry and who were then followed over 30 years.

Despite the lack of traditional risks, women who were inflamed as defined by hsCRP levels > 3 mg/L had a 77% increased lifetime risk of coronary heart disease, a 39% increased lifetime risk of stroke, and a 52% increased lifetime risk of any major cardiovascular event.

Additionally, researchers released a new analysis of randomized trial data showing that "SMuRF-Less but Inflamed" patients can reduce their risk of heart attack and stroke by 38% using statin therapy.

While those with inflammation should aggressively initiate lifestyle and behavioral preventive efforts, statin therapy could also play an important role in helping reduce risk among these individuals, say the researchers.

 Paul Ridker et al, C-Reactive Protein and Cardiovascular Risk Among Women with No Standard Modifiable Risk Factors: Evaluating The "SMuRF-Less but Inflamed", (2025). DOI: 10.1093/eurheartj/ehaf658

Comment by Dr. Krishna Kumari Challa on Friday

 Microbes in soil may affect hormones tied to love, mental health and social bonds

Experts are exploring evidence that microbes in the soil and the environments around us can affect human microbiota and the "gut-brain axis," potentially shaping emotional states and relationship dynamics—including aspects of romantic love.

They outline the idea in a review article in mSystems proposing how the human gut microbiome might influence hormonal pathways involved in emotions commonly associated with love.

This is not claiming microbes 'cause' love or hatred. The aim is to map plausible biological routes, grounded in microbiology and endocrinology, that researchers can now evaluate with rigorous human studies.

The mini-review, "Does a microbial-endocrine interplay shape love-associated emotions in humans? A hypothesis," synthesizes evidence that microbes can modulate hormones and key neurotransmitters such as dopamine, serotonin and oxytocin.

The researchers are exploring how the evolutionary underpinnings of microbial-endocrine interactions could provide important insights into how microbes influence emotions beyond love, including hate and aggression.

If these pathways are confirmed, the findings could open avenues for microbiome-informed strategies to support mental health and relational well-being. For now, it provides a roadmap for careful, hypothesis-driven science.

Jake M. Robinson et al, Does a microbial-endocrine interplay shape love-associated emotions in humans? A hypothesis, mSystems (2025). DOI: 10.1128/msystems.00415-25

Xin Sun et al, Unforeseen high continental-scale soil microbiome homogenization in urban greenspaces, Nature Cities (2025). DOI: 10.1038/s44284-025-00294-y

Comment by Dr. Krishna Kumari Challa on Friday

How pigments affect the weight of bird feathers

Birds are some of the most striking creatures on Earth, coming in a rainbow of colors that serve several important functions, such as attracting a mate and communicating with other birds. These vibrant hues are produced by pigments, primarily melanin, but a major unknown until now was how much these pigments weigh. Since wings need to be as light as possible for flight, understanding pigmentation weight may tell us something about the trade-off between the evolutionary benefits of colored feathers and the physical cost of carrying that weight.

In a new study published in the journal Biology Letters, scientists  have investigated how much melanin adds to the weight of feathers and the difference in weight between the two main chemical forms of melanin—eumelanin (responsible for brown and black colors) and pheomelanin (responsible for reds and lighter colors).

The researchers analyzed the feathers from 109 bird specimens across 19 different species, including the common kingfisher (Alcedo atthis), the golden eagle (Aquila chrysaetos) and the Eurasian bullfinch (Pyrrhula pyrrhula). They examined feathers with mixed colors and those with single, pure colors, and used a chemical process involving sodium hydroxide or caustic soda, as it is more commonly known, to extract the pigments. Once extracted, they were weighed and compared to the original weight of the feathers.

According to the scientists, melanin pigments account for about 22% of a feather's total weight, and in the most pigmented feathers, this weight is no more than 25%. Additionally, the two types of pigments don't weigh the same. Eumelanin, which makes feathers black or brown, was significantly heavier than pheomelanin, which produces lighter colors.

The paper suggests that a bird has to expend more energy to carry the weight of certain feather colors, which could explain why birds have evolved such a wide variety of hues, as the scientists write in their paper. 

The researchers suggested that birds in cold climates, like snowy owls, didn't just evolve white feathers for camouflage. The lack of a heavy pigment would allow them to grow thicker, more insulating feathers without adding too much weight. Therefore, they can stay warm and still be able to fly. Additionally, migratory birds may have evolved lighter feathers to reduce the energy cost of flying long distances.

Ismael Galván et al, Pigment contribution to feather mass depends on melanin form and is restricted to approximately 25%, Biology Letters (2025). DOI: 10.1098/rsbl.2025.0299

Comment by Dr. Krishna Kumari Challa on Friday

Glow-in-the-dark succulents that recharge with sunlight could pave way to plant-based lighting systems

From mushrooms that cast a soft green glow to plankton that glimmers sparkling blue, glowing plants are nothing new to nature. Now, scientists are bringing that light to houseplants.

Reporting in the journal Matter, researchers crafted glow-in-the-dark succulents that recharge in sunlight. Injected with light-emitting compounds, the plants can shine in various colors and rival a small night light at their brightest. The simple, low-cost method may help lay the foundation for sustainable, plant-based lighting systems.

Researchers used afterglow phosphor particles—materials similar to those found in glow-in-the-dark toys. These compounds absorb light and release it slowly over time.

For the particles to travel through leaf tissues, the researchers had to get the size just right: around 7 micrometers, roughly the width of a red blood cell.

Smaller, nano-sized particles move easily within the plant but are dimmer. Larger particles glowed brighter but couldn't travel far inside the plant.

The team then injected the particles into several plant species, including succulents and non-succulents like golden pothos and bok choy. But only the succulents produced a strong glow, thanks to the narrow, uniform, and evenly distributed channels within the leaf that helped to disperse the particles more effectively. After a couple of minutes of exposure to sunlight or indoor LED light, the modified plants glowed for up to two hours.

The particles diffused in just seconds, and the entire succulent leaf glowed.

By using different types of phosphors, the researchers created plants that shine in various colors, including green, red, and blue. They even built a glowing plant wall with 56 succulents, bright enough to illuminate nearby objects and read texts.

Each plant takes about 10 minutes to prepare.

The glowing succulents' light fades over time, and the team is still studying the long-term safety of the materials for the plants.

Sunlight-powered multicolor and uniform luminescence in material-engineered living plants, Matter (2025). DOI: 10.1016/j.matt.2025.102370

Comment by Dr. Krishna Kumari Challa on Friday

Cells 'vomit' waste to promote healing, but it comes with a trade-off

When injured, cells have well-regulated responses to promote healing. These include a long-studied self-destruction process that cleans up dead and damaged cells as well as a more recently identified phenomenon that helps older cells revert to what appears to be a younger state to help grow back healthy tissue.

Now, a new study in mice  reveals a previously unknown cellular purging process that may help injured cells revert to a stem cell-like state more rapidly. The investigators have dubbed this newly discovered response cathartocytosis, taking from Greek root words that mean cellular cleansing.

Published in the journal Cell Reports, the study used a mouse model of stomach injury to provide new insights into how cells heal—or fail to heal—in response to damage, such as from an infection or inflammatory disease.

After an injury, the cell's job is to repair that injury. But the cell's mature cellular machinery for doing its normal job gets in the way. So, this cellular cleanse is a quick way of getting rid of that machinery so it can rapidly become a small, primitive cell capable of proliferating and repairing the injury. Researchers identified this process in the GI tract, but they suspect it is relevant in other tissues as well.

The researchers identified cathartocytosis within an important regenerative injury response called paligenosis. 

In paligenosis, injured cells shift away from their normal roles and undergo a reprogramming process to an immature state, behaving like rapidly dividing stem cells, as happens during development. Originally, the researchers assumed the decluttering of cellular machinery in preparation for this reprogramming happens entirely inside cellular compartments called lysosomes, where waste is digested in a slow and contained process. From the start, though, the researchers noticed debris outside the cells. They initially dismissed this as unimportant, but the more external waste they saw in their early studies, the more they began to suspect that something deliberate was going on. They utilized a model of mouse stomach injury that triggered the reprogramming of mature cells to a stem cell state all at once, making it obvious that the "vomiting" response—now happening in all the stomach cells simultaneously—was a feature of paligenosis, not a bug.

In other words, the vomiting process was not just an accidental spill here and there, but a newly identified, standard way cells behaved in response to injury.

Although they discovered cathartocytosis happening during paligenosis, the researchers said cells could potentially use cathartocytosis to jettison waste in other, more worrisome situations, like giving mature cells that ability to start to act like cancer cells.

While the newly discovered cathartocytosis process may help injured cells proceed through paligenosis and regenerate healthy tissue more rapidly, the trade-off comes in the form of additional waste products that could fuel inflammatory states, making chronic injuries harder to resolve and correlating with an increased risk of cancer development.

 Jeffrey W. Brown et al, Cathartocytosis: Jettisoning of cellular material during reprogramming of differentiated cells, Cell Reports (2025). DOI: 10.1016/j.celrep.2025.116070

Comment by Dr. Krishna Kumari Challa on Thursday

Why Were Dinosaurs So Big?

Metabolic adaptations, air sac-filled bones, and evolutionary pressure likely contributed to dinosaurs’ gigantism.

Scientists have found evidence that the long-necked and long-tailed sauropods had a comparatively slower metabolism relative to today’s large mammals, which indicates that they likely didn’t have to eat as much. (1)

And when sauropods did eat, they likely swallowed most of their food whole: Sauropods’ teeth had very little wear, unlike those of other herbivorous species, such as the duck-billed dinosaurs, and even mammals. (2,3)They could ‘vacuum up’ a lot of food without having to spend a lot of time chewing.

Some sauropod bones were also filled with air sacs, which could make even larger body sizes mechanically feasible.  (4)This adaptive anatomical feature is found in many birds, dinosaurs’ closest living relatives, and it helps reduce their body weight and promote flight.

Sources: 

1. Baumgart SL, et al. The living dinosaur: accomplishments and challenges of reconstructi.... Biol Lett. 2025;21(5):20250126.

2. Whitlock JA. Inferences of diplodocoid (Sauropoda: Dinosauria) feeding behavior .... PLoS One. 2011;6(4):e18304.

3. Fiorillo AR. Dental micro wear patterns of the sauropod dinosaurs camarasaurus a.... Hist Biol. 1998;13(1):1-16.

4. Wedel MJ. Evidence for bird-like air sacs in saurischian dinosaurs. J Exp Zool A Ecol Genet Physiol. 2009;311(8):611-628.

5. https://www.the-scientist.com/why-were-dinosaurs-so-big-73254?utm_c...

Comment by Dr. Krishna Kumari Challa on Thursday

Exercise intensity could be impacting your gut

While exercise is great for both your mental and physical health, new research from Edith Cowan University (ECU) has found that exercise intensity could result in changes to the internal gut biome.

Researchers undertook research into the impact of high and low training loads on athletes, in the hope of assisting athletes to improve their overall health, well-being and performance by better understanding the gut microbiome.

It appears that athletes have a different gut microbiota when compared with the general population. This includes greater total short chain fatty acid concentrations, alpha diversity, an increased abundance of some bacteria and a lower abundance of others.

 while the differing microbiome between athletes and the public could likely be due to the differences in their dietary intake , fitness markers, which include oxygen uptake, have also been correlated.

Published in the Journal of the International Society of Sports Nutrition, this research uncovered that training load had an influence on gut health markers in athletes, with differences detected in short-chain fatty acid concentrations and the abundance of specific bacteria.

 One of the potential reasons for the change in the gut could be the higher levels of blood lactate which results from higher intensity training. The lactate produced in muscle is transported to the gut to be metabolized, which could potentially result in increased bacteria in the gut.

The changes found in the gut biome when comparing high training loads to low training loads, were also related to diet.

Another observation made during the research was the significant slowing of gut transit times in athletes during low training loads. That slowing of transit time during the low training load appears to also be impacting the gut microbiome for an athlete.

The gut may play a role in lactate metabolism and regulating pH levels, both of which could impact performance and overall athlete health, say the researchers. 

B. Charlesson et al, Training load influences gut microbiome of highly trained rowing athletes, Journal of the International Society of Sports Nutrition (2025). DOI: 10.1080/15502783.2025.2507952

Comment by Dr. Krishna Kumari Challa on Thursday

Positive emotional bias could be an early sign of cognitive decline in aging populations

As people age, they display a bias in recognizing emotions as positive—to the point of improperly labeling neutral or negative emotions as positive.

Some researchers theorize this bias is an adaptive mechanism to support mental and emotional wellness, but new evidence suggests it may be a sign of cognitive decline.

In a JNeurosci paper, researchers advance understanding of what this positive emotional bias that elders exhibit signifies about their brains' health.

A large pool of participants (665) viewed faces in an emotion recognition task. Age-related positivity bias correlated with poorer cognitive performance in two assessments, but not necessarily emotional decline as measured by examining nonclinical depressive symptoms.

The researchers also observed structural changes in brain areas associated with emotional processing and changes in how these areas communicate to another brain region involved in social decisions. Thus, positivity bias from aging impacts the brain in observable ways that could be leveraged clinically to detect early rising signs of age-related neurodegeneration and cognitive decline.

Researchers are now  exploring how these findings relate to older adults with early cognitive decline, particularly those showing signs of apathy, which is often another early sign of dementia.

 Age-Related Positivity Bias in Emotion Recognition is Linked to Lower Cognitive Performance and Altered Amygdala–Orbitofrontal Connectivity, JNeurosci (2025). DOI: 10.1523/JNEUROSCI.0386-25.2025

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