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Comment by Dr. Krishna Kumari Challa on June 26, 2026 at 11:49am

The universe should look the same in all directions at large scales, but DESI data suggest otherwise

Earlier this year, the Dark Energy Spectroscopic Instrument (DESI) completed observations that mapped 47 million galaxies across 11 billion light-years, allowing astronomers to better evaluate the large-scale structure of the visible universe. After studying these data, astronomers say the universe may not look the same in all directions. Their results, published in Nature, contradict a fundamental assumption in modern cosmology.
At the scale of a single galaxy or local groups of galaxies, the universe clearly appears to be anisotropic, meaning the structure is different depending on which direction you look. In one direction, there may be more void space, while another direction may have a cluster of galaxies.

However, the cosmological principle says that at larger scales, the universe consists of matter that is more or less distributed evenly in all directions. This is based on the Copernican principle, which states that there should be no "special observers" in the universe, meaning that at large scales, the universe should look the same from anywhere else in the universe.

For example, if you imagine the universe as a piece of cloth and zoom in to the scale of the individual fibers, you can clearly see areas of empty space and filament-like fibers that connect to make a larger structure. Yet when you zoom out to much larger scales, the cloth appears to be the same everywhere, with evenly distributed materials.
Research focusing on cosmic background radiation has provided some support for the cosmological principle, but other studies have shown that anisotropic structure still exists at scales of tens to hundreds of megaparsecs. However, the statistical significance of these studies is uncertain.
The authors of the new study say that past anisotropy probes tested for preferred directions instead of evaluating more general directional structure.
They found that galaxy samples from DESI show persistent anisotropic structure in galaxy distribution out to roughly gigaparsec scales, meaning galaxies were clumping together more than they should at scales far larger than those previously examined. Taking previous studies suggesting anisotropy at megaparsec scales as an example, this study indicates anisotropy still exists at scales 1,000 times larger.

"These results provide direct evidence that directional coherence persists to larger scales than predicted in the standard framework, challenging the assumption of large-scale isotropy," the study authors write.

Francesco Sylos Labini et al, Detection of anisotropic cosmic structures on a gigaparsec scale, Nature (2026). DOI: 10.1038/s41586-026-10702-5

Comment by Dr. Krishna Kumari Challa on June 26, 2026 at 11:41am

Poor metabolic health can age the brain even in young people, finds new large-scale study
Two people of very different ages can have a similar level of biological aging in their brains. Such an occurrence is possible because aging and metabolic health follow two distinct pathways that influence brain health. While it is known that the brain changes as we get older, a recent study analyzing more than 3,000 brain scans found that metabolic issues affect the brain through a different biological pathway than aging does.
The researchers found that the two axes operate independently of one another, meaning a person can be relatively young yet experience brain changes associated with poor metabolic health. These changes, driven by metabolic factors, were also linked to real-world cognitive performance.

People with poorer metabolic health generally struggled more with tasks that required cognitive flexibility, or the ability to shift between competing demands. The association was strongest in females.

The aging axis affects the brain by eroding its structural integrity. This includes thinning of the brain's outer layer and vascular dysfunction, which slows the flow of blood through the brain's vessels. The metabolic axis works differently. Instead of one main driver, it has an army of factors, including body weight, blood pressure and cholesterol, all acting together.

Their shared effect is a drop in cerebral perfusion, that is, less blood actually reaching the brain.

Asa Farahani et al, Aging and metabolism contribute separately to brain–body health, PLOS Biology (2026). DOI: 10.1371/journal.pbio.3003856

Comment by Dr. Krishna Kumari Challa on June 26, 2026 at 11:38am

A species of gut bacteria could ease anxiety and diarrhea-predominant IBS

Irritable bowel syndrome (IBS) is a condition characterized by abdominal pain, bloating and changes in bowel movements, estimated to affect between 10% and 15% of people worldwide. Past studies suggest that in many cases this condition is accompanied by anxiety, an emotional state marked by worry, fear and/or overthinking about specific life events.
While IBS and anxiety are known to often occur together, the biological processes linking the two have not yet been fully elucidated. One possibility is that bacteria and other microorganisms living in the digestive tract, broadly referred to as gut microbiota, contribute to these biological processes.
Researchers carried out a study aimed at shedding more light on the biological mechanisms linking a type of IBS called diarrhea-predominant IBS (IBS-D), which is associated with frequent loose stools, with anxiety.

Their paper, published in Translational Psychiatry, suggests that a species of gut-inhabiting bacteria called Phocaeicola vulgatus could contribute to easing anxiety associated with IBS-D.
The researchers also carried out a series of genetic analyses on their mouse model of IBS to further explore the effects of the Phocaeicola vulgatus bacteria. The results of these analyses confirmed that the bacteria protected the mouse brain from anxiety.

Finally, giving live Phocaeicola vulgatus to mice eased anxiety by calming brain inflammation and repairing damaged neurons in the amygdala.

Jiacheng Wu et al, Phocaeicola vulgatus improves anxiety-like behavior by ameliorating amygdala neuroinflammation and the neurite impairment in IBS, Translational Psychiatry (2026). DOI: 10.1038/s41398-026-04142-y.

Comment by Dr. Krishna Kumari Challa on June 25, 2026 at 11:41am

Why pollution affects some asthma patients more than others

For many people with asthma, air-quality advisories are harbingers of worsening symptoms. But the extent to which pollution exacerbates asthma varies widely from person to person.
In a study published in eBioMedicine, researchers identified biological pathways that begin to uncover this mystery, showing how air-pollution exposure interacts with a person's genes.

The study—which is among the largest and most comprehensive of its kind to date—could eventually lead to new avenues for asthma drug development, as well as potential new biomarkers and public health interventions targeted to those who are most vulnerable to pollution-exacerbated asthma.
Asthma severity responses to PM2.5 vary due to genetic differences in oxidative stress–related pathways. Whole-genome, exposure, and airway transcriptomic data identified variants in seven genes, including OXSR1, PXDN, and TPO, that alter pollution-induced RNA responses and are associated with lower lung function. These pathways suggest potential targets for precision diagnostics and interventions.

Using data from nearly 1,000 adults with asthma the analysis included a combination of whole-genome sequencing, air-pollution exposure data and gene-expression profiling. Among the thousands of genes in the human genome, the team focused on about 450 genes that control oxidative stress, a process in which highly reactive molecules can damage cells and tissues.
Those stresses on cells can translate into serious physiologic effects, like worsening lung function or asthma exacerbations.
The team focused on how these genes interacted with the environmental stress of exposure to fine particulate matter known as PM2.5. These microscopic particles, with a diameter less than that of a human hair (less than 2.5 microns), are small enough to penetrate deep into the lungs and are widely considered one of the most harmful components of air pollution.
A clear relationship emerged.

In these individuals who were living with asthma, the higher their exposure to this particulate matter, the lower their lung function overall.
The researchers found that the most vulnerable patients carried variants in seven oxidative stress–related genes that shape how the body responds to cellular damage from pollution. These genetic variants appear to influence how airway cells respond to the PM2.5 exposure, with some variants enhancing protection from PM2.5, while others appear to worsen the damage.

Individuals with less common variants in two specific genes, called OXSR1 and PXDN, had disproportionately worse lung function due to lower protective RNA responses to pollution. Those with a specific variant in another gene, called TPO, had worse lung function as well, but for them, it was due to stronger RNA responses.

The molecular pathways described in the study could point to targets for new therapies—and open the door to much more.

A cross-sectional study of oxidative stress pathway genotypes and their interactions with environmental pollutant levels identifies associations with gene expression and lung function, eBioMedicine (2026). DOI: 10.1016/j.ebiom.2026.106334

Comment by Dr. Krishna Kumari Challa on June 25, 2026 at 9:14am

Uneven cerebellum aging may partly explain why some older adults stay mentally sharp

The name "cerebellum" comes from Latin and means "little brain." While it is smaller than the rest of the brain, it contains most of the brain's neurons and coordinates a variety of functions and processes in the brain and body. These include balance, posture and fine motor skills like typing or writing.

Scientists may have discovered a new role for the cerebellum, the part of the brain that sits at the base of the skull. A new paper published in the journal Nature Neuroscience reports that different parts of the cerebellum change at different rates with age, which may be linked to differences in cognitive abilities and memory in later life. This may help explain why some people stay sharper as they get older.
The team analyzed brain scans and cognitive test scores from more than 700 healthy U.S. individuals whose data had been collected as part of the Human Connectome Project. Then they mapped out 11 separate sections on the digital scans and calculated how the volume of each region changed with age.

The scientists discovered that the cerebellum does not age evenly. Regions at the back, which are more connected to higher-order thinking networks, show faster shrinking than front regions involved in basic movement.
"We show a spatially heterogeneous pattern of aging in which specific association and motor-related regions show steeper relationships with age than other lobules," the authors wrote in their paper.

The data also revealed that people with a larger cerebellum scored higher on memory and thinking tests as they aged than people with a smaller cerebellum.

The research team saw a similar trend in a pool of about 47,000 adults in the UK Biobank and Alzheimer's Disease Neuroimaging Initiative. However, in people with Alzheimer's, it appears that support from the cerebellum has its limits as the disease progresses. "This supports a threshold-reserve model, in which the cerebellum helps sustain cognition until pathology becomes widespread."

The researchers cannot say for certain whether a larger cerebellum directly causes better cognition in old age. They have shown a link or association, not a true cause-and-effect relationship. Also, their findings might not apply to everyone globally because most of the study data came from white individuals with high levels of education.

Federico d'Oleire Uquillas et al, Cerebellar aging is spatially heterogeneous and supports cognitive resilience in later life, Nature Neuroscience (2026). DOI: 10.1038/s41593-026-02289-x

Comment by Dr. Krishna Kumari Challa on June 25, 2026 at 9:08am

After the week of light monitoring, the researchers followed the participants' health for an average of nearly eight years. The data pointed to a clear vulnerability threshold for eye health: average exposure to evening light exceeding 1,000 lux. In individuals consistently exposed to light above this level in the evening, the risk of developing major eye diseases rose sharply.

They observed a 31% higher risk of age-related macular degeneration, an 18% higher risk of cataracts and a 47% higher risk of primary open-angle glaucoma. The more time a person spent in bright light, the higher the risk.

Researchers suggest that this damage might be linked to disrupted circadian rhythms and exposure to blue light from modern LEDs, which can trigger oxidative stress and even cause photochemical damage in the delicate cells of the lens and retina.

Since high-intensity evening light is a modifiable risk factor, health care professionals can help people protect their long-term vision by choosing circadian-safe lighting, like dimming screens and using lower-intensity lights before bed.

Xiaoqian Wu et al, Association of high-intensity evening light exposure with risk of incident age-related macular degeneration, cataract, and glaucoma: a prospective cohort study of 82,826 participants, GeroScience (2026). DOI: 10.1007/s11357-026-02307-7

Part 2

Comment by Dr. Krishna Kumari Challa on June 25, 2026 at 9:08am

Exposure to bright evening light linked to higher risk of age-related eye disease

The eye does more than help us see. It also plays a key role in setting our internal body clock, and, as a result, the amount and timing of light exposure may influence how the eye ages over time. Age-related eye diseases (AREDs), such as macular degeneration, cataracts and glaucoma, are a group of conditions that commonly develop in older adults and can lead to significant vision loss.

Many of these conditions share biological processes, including long-term inflammation, oxidative stress and disruptions in cellular energy production.

Every sunrise and sunset sends the body a signal, keeping the circadian clock running on a roughly 24-hour cycle. This clock evolved so organisms could adapt to Earth's daily rotation, syncing their biology to the pattern of day and night. Artificial lighting has freed human societies from relying on the sun to go about daily life, extending activity well into the night, but this convenience comes with a trade-off.
Researchers found that exposure to bright artificial light in the evening, especially between 8 p.m. and 11:30 p.m., may significantly increase the risk of developing serious eye diseases later in life. Those exposed to light levels above 1000 lux during these hours showed a notably higher likelihood of conditions such as age-related macular degeneration (AMD), cataracts and glaucoma.

It is not your living room lamp one needs to worry about, as standard indoor lighting, usually between 100 and 500 lux, stays safely within range. The real risk comes from extreme evening brightness from modern high-brightness screens and electronic displays, or occupational lighting in high-precision fields.

Researchers already knew there is a critical evening transition window when the body's internal clock is especially sensitive to light. However, there was limited real-world data linking specific light levels during this period to the development of actual eye diseases.

In this study, the researchers followed a database of 82,826 participants from the UK Biobank. Anyone who already had eye diseases was excluded to specifically track new cases that developed over time.
Part 1

Comment by Dr. Krishna Kumari Challa on June 24, 2026 at 9:54am

Vitamin D and calcium supplements may not protect against bone fractures, large new study suggests
Calcium or vitamin D supplements alone show little to no reduction in fractures or falls in adults, and combined supplementation yields only very small, clinically marginal benefits. The findings question routine supplementation for community-dwelling adults without deficiency or osteoporosis. Evidence more strongly supports weight-bearing exercise, balance training, and overall lifestyle measures for fracture and fall prevention.

original article.

Comment by Dr. Krishna Kumari Challa on June 24, 2026 at 9:50am

Hope for spinal injuries as pigs walk again after experimental gel treatment for severed spinal cords

In humans and other mammals, spinal cord injuries can be devastating, leading to permanent loss of movement, sensation and bladder control. When severed axons (the long fibers that carry messages between nerve cells) cannot regrow, a dense scar forms, preventing nerve signals from passing the injury site.

But the situation is different for some primitive invertebrates, which can rapidly reconnect severed nerves by fusing them. Inspired by this natural phenomenon, scientists report that they have successfully reconnected severed spinal cords in pigs, enabling them to walk again.

When a spinal cord is completely cut, the two severed ends naturally pull away from each other. In microscopic roundworms, for example, the nerve ends automatically find each other and fuse together. The researchers realized that to recreate a natural fusion process like this, they needed a material to fill the empty space and hold the two ends together.
As they detail in a paper published in the journal PLOS One, they engineered a fusogen-based gel designed to weld damaged nerve membranes back together. It contains a chemical used in medicine, polyethylene glycol, and a biological polymer, chitosan.

Pigs with complete spinal cord transections treated with a polyethylene glycol–chitosan fusogen gel showed rapid sensory recovery, restoration of bladder control by day 5, and independent walking by day 60, unlike untreated controls. Histology indicated reduced scarring and nerve fibers crossing the lesion, consistent with axonal fusion–mediated neurorepair.

Given the rapid clinical improvement observed, the therapeutic effects ... cannot be attributed solely to axonal regeneration ... This points to immediate neurorepair mechanisms, namely axonal fusion, being the primary driver of the initial recovery.
While this pig study is a significant advance, human clinical trials are likely still a long way off, as larger animal studies will be needed first. However, the research has demonstrated that damaged nerve fibers may reconnect after spinal injury, giving hope for future spinal treatments, as the researchers note.

Michael Lebenstein-Gumovski et al, Fusogen-induced recovery of spinal cord function and morphology after complete transection, PLOS One (2026). DOI: 10.1371/journal.pone.0349579

Comment by Dr. Krishna Kumari Challa on June 24, 2026 at 9:45am

White barn owls may use moonlight to startle prey
Male barn owls with white plumage orient flights toward the moon and preferentially hunt in brighter, unshaded areas, increasing exposure of their bright feathers to prey. Dive-level capture probability is similar across colors and light levels, but white males capture more prey per hour on bright nights, supporting a startle rather than background-matching function of whiteness.

Kim Schalcher et al, Barn owl color morphs hunt differently in moonlight, Current Biology (2026). DOI: 10.1016/j.cub.2026.05.020

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