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Understanding Why Alzheimer’s Disease-Related Brain Damage Doesn’t Immediately Trigger Symptoms

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Examining Resilience to Alzheimer’s Disease: Why Some Individuals Remain Symptom-Free

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Recent studies reveal that some individuals exhibit brain changes tied to Alzheimer’s disease yet show no symptoms like memory loss. Though the reasons remain unclear, innovative research is uncovering protective factors that may prevent cognitive decline.

Alzheimer’s disease is marked by amyloid plaques and tau tangles accumulating in the brain, widely believed to contribute to cognitive decline. However, some individuals, known for their resilience, defy this notion. In 2022, Henne Holstege and her team at the University Medical Center in Amsterdam discovered that certain centenarians retain good cognitive function despite these pathological changes.

Expanding on this research, the team conducted a new study involving 190 deceased individuals. Among them, 88 had Alzheimer’s diagnoses, while 53 showed no signs of the disease at death. Their ages ranged from 50 to 99, and 49 were centenarians with no dementia, though 18 exhibited cognitive impairment previously.

The focus was on the middle temporal gyrus—an early site of amyloid plaques and tau tangles in Alzheimer’s. Interestingly, centenarians with elevated amyloid levels had tau levels akin to those without Alzheimer’s, suggesting that limiting tau accumulation is critical for resilience, according to Holstege.

While amyloid plaques are linked to cognitive decline, Holstege posits that tau accumulation may activate a cascade of symptoms. Notably, amyloid plaques alone may not cause significant tau tangling. “Without amyloid, tau can’t spread,” she explains.

Further analysis of approximately 3,500 brain proteins revealed only five were significantly associated with high amyloid plaques, while nearly 670 correlated with tau tangles. Many of these proteins are involved in crucial metabolic processes like cell growth and waste clearance. Holstege emphasizes, “With amyloid, everything changes; with tau, it’s a different story.”

In the cohort of 18 centenarians with high amyloid levels, 13 showed significant tau spread throughout the middle temporal gyrus, a pattern similar to Alzheimer’s, but the overall tau presence remained low.

This distinction is vital, as diagnosis hinges on tau spread, indicating that accumulation, not just proliferation, triggers cognitive decline. “We must understand that proliferation doesn’t mean abundance,” Holstege clarifies.

In a second study, Katherine Prater and her team at the University of Washington examined 33 deceased individuals—10 diagnosed with Alzheimer’s, 10 showing no signs, and 13 deemed resilient. Most subjects were over 80 and underwent cognitive assessments within a year before death.

In line with previous findings, the research indicated that tau was present but not accumulated in resilient brains. Though the mechanisms remain elusive, Prater theorizes that microglia—immune cells regulating brain inflammation—might play a crucial role in maintaining cognitive function in resilience.

Previous research has shown that microglia often become dysfunctional in Alzheimer’s disease, contributing to degenerative processes. While the researchers could not analyze microglia extensively, Holstege noted their significance.

The team also conducted genetic studies on microglia from the dorsolateral prefrontal cortex, essential for managing complex tasks. They discovered that resilient individuals’ microglia exhibited heightened activity in messenger RNA transport genes compared to those with Alzheimer’s. This suggests effective gene transport, vital for protein synthesis, is preserved in resilient brains.

“Disruptions in this process can severely impact cell function,” Dr. Prater remarked at the Neuroscience Society meeting in San Diego. However, its direct relationship to Alzheimer’s resilience remains to be elucidated.

Moreover, resilient microglia demonstrated reduced activity in metabolic energy genes compared to those in Alzheimer’s patients, mirroring patterns in healthy individuals. This suggests heightened energy expenditure in Alzheimer’s due to inflammatory states that disrupt neuronal connections and lead to cell death.

“Both studies indicate that the human brain possesses mechanisms to mitigate tau burdens,” Prater concludes. Insights gained from this research could pave the way for new interventions to delay or even prevent Alzheimer’s disease. “While we aren’t close to a cure, the biology offers hope,” she stated.

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  • Brain/
  • Alzheimer’s Disease

Source: www.newscientist.com

Interstellar Objects Such as 3I/ATLAS May Trigger Planet Formation Around High-Mass Stars

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The findings of 1I/Oumuamua, 2I/Borisov, and 3I/ATLAS have revealed a substantial number of interstellar objects in the cosmos. Their widespread presence suggests that such objects are also found in protoplanetary disks, essential sites for planet formation. In these disks, interstellar objects could potentially bypass the 1-meter (3.3-foot) barrier in the traditional model of planet formation, initiating the creation of giant exoplanets.

This colorized image was taken by the CaSSIS instrument aboard ESA’s Trace Gas Orbiter on October 3, 2025, and displays the interstellar comet 3I/ATLAS. Image credit: ESA/TGO/CaSSIS.

Interstellar objects, including asteroids and comets, are those that have been expelled from their original star systems and are now traversing interstellar space, occasionally intersecting with other star systems.

Since 2017, astronomers have identified three interstellar objects passing through our solar system: 1I/’Oumuamua, 2I/Borisov, and the latest, 3I/ATLAS.

“Nevertheless, interstellar objects may exert a more significant influence than it appears at first glance,” states Professor Susanne Falzner, an astronomer at Jülich National Park.

“Interstellar objects could potentially incite planet formation, particularly around high-mass stars.”

Planets are formed from dusty disks that surround young stars through a process known as accretion. This theory posits that smaller particles gradually coalesce into larger objects, culminating in the formation of planet-sized bodies.

However, researchers have faced challenges in explaining how accretion can create objects larger than a meter amidst the chaotic collisions of planet-forming disks surrounding young stars. In simulations, the rocks tend to either bounce off each other or break apart upon collision, rather than adhering together.

Interstellar objects might help circumvent this issue. The researchers’ model illustrates how the dust-laden disks surrounding young stars can gravitationally capture millions of interstellar objects akin to 1I/’Oumuamua, which is estimated to be around 100 meters (328 feet) long.

“Interstellar space will supply ready-made seeds for the next phase of planet formation,” said Professor Falzner.

If interstellar objects could act as seeds for planets, it would also resolve another enigma.

Gas giant planets like Jupiter are scarce around smaller and colder stars, referred to as M dwarfs, but are more frequently found around larger stars similar to the Sun.

However, the lifespan of a planet-forming disk around a Sun-like star lasts only about 2 million years before dissipating, complicating the formation of gas giant planets in such a brief time frame.

That said, if captured interstellar objects serve as seeds for accretion, the planet-forming process could hasten, allowing giant planets to form within the lifetime of the disk.

“The more massive a star is, the more effectively it can capture interstellar objects in its disk,” Professor Falzner explained.

“As a result, planet formation seeded with interstellar objects should proceed more efficiently around these stars, offering a rapid pathway to forming giant planets.”

“And their swift formation is precisely what we’ve observed.”

Professor Falzner presented her findings in September 2025 during the EPSC-DPS2025 joint meeting in Helsinki, Finland.

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S. Falzner. 2025. Interstellar objects primarily function as seeds for planet formation surrounding high-mass stars. EPSC abstract 18: EPSC-DPS2025-1927; doi: 10.5194/epsc-dps2025-1927

Source: www.sci.news

The Elusive Trigger Behind Parkinson’s Disease Finally Unveiled

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For the first time, researchers have successfully visualized and quantified small protein clusters in the human brain that may signal the onset of Parkinson’s disease.

These clusters, known as alpha-synuclein oligomers, have long been implicated in some of the fastest-expanding neurological disorders worldwide but had never been observed in brain tissue until now.

To identify these elusive proteins, the research team utilized a novel imaging method called Advanced Sensing of Parkinson’s Disease (ASA-PD) aggregates, which renders these nanometer-scale (one billionth of a meter) oligomers visible.

For decades, clinicians could confirm a diagnosis of Parkinson’s disease only by detecting larger deposits of proteins that build up in neurons. However, many researchers believe the disease actually initiates with these smaller oligomers.

“You can think of Lewy bodies as a sort of morbid gravestone,” stated Professor Stephen Lee from Cambridge’s Yusuf Hameed Department of Chemistry, who co-led the study. BBC Science Focus. “They indicate where the disease resides and its progression.”

To investigate the earlier phases of the disease, the team compared post-mortem brain samples from individuals with Parkinson’s disease to those from healthy individuals. Oligomers were present in both cohorts, surprising scientists, but were more abundant and vibrant in the brains of Parkinson’s patients.

“This marks the first occasion we’ve directly observed oligomers in human brain tissue at this scale, akin to spotting stars in daylight,” commented Dr. Rebecca Andrews, Co-First Author and former postdoctoral researcher in Lee’s lab.

The researchers also discovered subtle variations in the distribution of oligomers, which could signify the earliest stages of the disease prior to the onset of symptoms.

Scientists were able to visualize and count α-synuclein oligomers (shown in red) in brain tissue samples. Interestingly, these puncta were present in both Parkinson’s patients and healthy individuals, as depicted in the images of two Parkinson’s patients (top) and two healthy controls (bottom) – credits: Andrews et al. (2025)

Lee emphasized that while this study is a significant advancement, it should not be misconstrued as a means to directly find treatments. “We’re not at that stage,” he noted. “This research actually allows us to engage with the very early stages of the disease. From a therapeutic standpoint, it lays the groundwork for future developments.”

Currently, over 10 million people globally suffer from Parkinson’s disease, which lacks a treatment that addresses the underlying condition. Existing medications can manage symptoms like tremors, but none target the disease’s root cause or halt its progression.

A collaborative team from the University of Cambridge, the University of London, the Francis Crick Institute, and Polytechnique Montreal aims to utilize these findings to enhance methods for monitoring the efficacy of diagnostic tests and experimental treatments.

This imaging technique is also applicable beyond just Parkinson’s disease. “This approach provides more than just a snapshot,” said Professor Lucian Weiss from Polytechnique Montréal, who co-led the study. “It maps protein changes throughout the brain and similar techniques can be applied to other neurodegenerative disorders such as Alzheimer’s and Huntington’s diseases.”

“Oligomers were once like needles in a haystack, and now that we know their precise locations, it enables us to target specific cell types in designated areas of the brain.”

The findings of this study have been published in Nature Biomedical Engineering.

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Source: www.sciencefocus.com

Hidden Food Allergens Often Trigger Serious Reactions

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Buckwheat seems to be a significant contributor to severe food allergies

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It appears that roughly one in seven instances of life-threatening allergic reactions is triggered by foods that lack allergen labeling, prompting researchers to call for policy changes in this area.

Food allergies are rising in prevalence; however, many regulatory allergen lists have not been updated in many years. For instance, the European Union’s Essential labeling of food lists mandates the disclosure of 14 different food allergens, like peanuts and soy, but relies on data that dates back to 2011.

To explore less recognized allergens, Dominique Sabouraud-Leclerc from Centre Hosvia University in France conducted an analysis along with her colleagues, examining 2,999 reports of food-induced anaphylaxis that were voluntarily submitted by medical professionals within an allergenic environment network from 2002 to 2023.

The research aimed to identify emerging food allergens, defined as substances not listed in the European Essential Labeling List but responsible for at least 1% of reported cases.

The researchers found that goat milk, sheep milk, and buckwheat accounted for 2.8% and 2.4% of cases, respectively. Following these, peas, lentils, and alphagal (sugars that can induce allergies to lean meat and other mammalian products) each contributed to 1-2% of reported incidences. Apple products and beeswax items, such as edible pollen, honey, and royal jelly, were also responsible for 1% of cases.

In total, new food allergies constituted 413 cases, approximately 14% of the overall reports.

In terms of reaction severity, goat and sheep cheese elicited particularly dangerous responses, especially among young boys, leading to two fatalities. Recurrent reactions and unexpected exposures, often found in sauces and thickeners primarily made from goat and sheep dairy, were most prevalent, followed by peas, lentils, buckwheat, and pine nuts.

In light of these findings, the team recommended incorporating these four food types into the essential European warning labels. These ingredients should be clearly highlighted on packaging, such as through bold text.

“Our primary aim is to safeguard allergic consumers and ensure they have access to clear information,” said Sabouraud-Leclerc. “This encompasses quality patient care, including proper diagnosis, education, emergency preparation, and understanding food labels.”

The data collected were primarily from France, Belgium, and Luxembourg, but the findings are likely relevant to other nations, with some variations in prevalence based on local culinary practices, according to Sabouraud-Leclerc. “Updating the EU list could inspire similar actions in other countries, creating a snowball effect,” she added.

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Source: www.newscientist.com

Could Israeli Airstrikes Trigger a Nuclear Incident in Iran?

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Iran’s Arak Heavy Water Nuclear Facility was damaged by Israeli bombing

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Israel’s assault regarding Iran’s nuclear activities has raised concerns about potential radioactive incidents, according to experts, including the director of the International Atomic Energy Agency (IAEA). New Scientist While there have been reports of radiological and chemical contamination at one nuclear enrichment facility, the overall risk remains low.

Peter Bryant from the University of Liverpool notes that the terms “nuclear” and “radiation” understandably provoke fear, but despite extensive bombings, there have been no reported external leaks as of now.

Iran’s nuclear ambitions trace back to the 1950s, including attempts to develop nuclear weapons. The country pledged to allow IAEA inspections to verify that its energy facilities are not being utilized for weapon production; however, the agency recently issued a report criticizing Iran for failing to comply with non-proliferation obligations. Evidence of uranium traces at certain plants suggests that a covert nuclear weapons program might still be in progress.

Following reports regarding Iranian facilities responsible for uranium enrichment, Israel launched its strikes. Naturally occurring uranium exists in a mixture of three isotopes, but the enriched variant has a greater proportion of uranium-235, which can be used for both electrical generation in reactors and for nuclear arms. Given this dual-purpose potential, Iran has committed to restricting enrichment under the Treaty on the Non-Proliferation of Nuclear Weapons.

Philip Bleak from the Middlebury International Institute in California points out that the IAEA reports indicate Iran has already accumulated over 400 kilograms of uranium concentrated to 60%. This quantity is adequate for multiple rudimentary nuclear weapons, and Israeli intelligence suggests that the actual figures may be underreported to the IAEA. Even uranium at 60% purity significantly exceeds the requirements for fueling a power plant, implying that Iran harbors intentions to develop nuclear capabilities.

Iran maintains two primary enrichment sites: the Fordow Fuel Enrichment Plant (FFEP) and the Natanz Nuclear Facility. Israel’s strikes on Natanz resulted in internal radiation leaks; however, according to the IAEA, there have been no signs of external contamination.

In contrast, the Fordow facility remains operational due to its underground location, making it susceptible to destruction only by powerful US munitions. Only a powerful US bomb could destroy it. Former President Donald Trump has indicated he might assess support for Israel in this matter.

The Arak Heavy Water Reactor has also been targeted in bombings; however, it was never commissioned and housed no radioactive substances. If operational, it could have enabled the conversion of uranium into plutonium, a material viable for nuclear weaponry. Additionally, the Isfahan Nuclear Technology Center and certain missile sites designed for nuclear weapons launch were also bombed.

Bleak asserts that fresh uranium poses “very modest” health risks irrespective of enrichment levels. “A significant amount must enter your body to have a meaningful impact, similar to what uranium miners experienced,” he explains.

This is why the enrichment facilities targeted in strikes represent minimal risk outside their immediate vicinity, according to Bryant. Moreover, since these plants are built deep underground for resistance against attacks, any radioactive emissions would be further contained. “Uranium fuel can be handled without issue,” states Bryant. “You would need to physically ingest it to face health problems.”

Nonetheless, should a working reactor be targeted and operational for months prior to an attack, it may accumulate “dangerous fission byproducts,” which represent a more significant radiological threat. Bleak warns that if such materials escape, scenarios akin to Chernobyl or Fukushima could arise.

Bryant expresses confidence that such leaks are exceedingly unlikely, attributing this to advancements in reactor design that can withstand heavy bombardments. Furthermore, civilian power plants are not core to Iran’s nuclear weapons program and are unlikely to be prioritized targets for Israel, he says. Bushehr, Iran’s only functioning nuclear power facility, has not been targeted thus far.

Despite assurances from scientific experts, New Scientist reports that IAEA Director Rafael Grossi cautioned earlier this week about the real risks of harm.

“I have consistently stated that we should never attack nuclear facilities, irrespective of the circumstances, as they can pose hazards to both humanity and the environment,” he asserted.

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Source: www.newscientist.com

Excessive salt intake may trigger eczema symptoms

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It is already known that excessive salt intake increases blood pressure.

Toufik Ahmed/iStockphoto/Getty Images

Researchers have found that people with the skin condition have higher levels of sodium in their urine, suggesting that excessive salt intake may be linked to eczema.

Over 200 million people Eczema affects many people around the world and is a skin condition that causes dry, cracked, itchy skin. Common causes include irritants in soaps and detergents, as well as environmental and food allergens. Previous studies have shown that: Frequent fast food consumption linked to increased risk of severe eczema For the children.

To see if salt plays a role, Katrina Abuaballah Researchers at the University of California, San Francisco (UCSF) looked at urine sample data from more than 215,800 adults who took part in the UK Biobank study, more than 10,800 of whom had eczema.

The researchers used each participant's urine sample to estimate urinary sodium excretion over a 24-hour period. About 90% of dietary sodium is excreted in the urine.This waste product therefore provides a relatively reliable way of measuring a person's salt intake.

Overall, study participants were estimated to have excreted an average of 3.01 grams of sodium in their urine over a 24-hour period. Typically around 2.5 grams per dayThis is the equivalent of 6 grams of salt, or 1 teaspoon.

The researchers found that for every gram of sodium excreted, participants were 11 percent more likely to be diagnosed with eczema, and their risk of ever developing eczema at any one time increased by 16 percent.

The team acknowledges that a single urine sample may not accurately reflect an individual's typical salt intake, but in another part of the study, the researchers looked at the daily diet of a different group of more than 13,000 U.S. adults and found further correlations between high salt intake and eczema.

In previous studies, Sodium activates immune system cells“The immune system responds to allergens and irritants in a way that triggers several inflammatory pathways,” Abuaballah said. People with eczema have an overactive immune response to allergens and irritants, which causes skin inflammation and subsequent symptoms.

Although the study suggests a link between high urinary sodium levels and eczema, team members say more research is needed to prove that the former causes the latter. Brenda Chanalso at UCSF.

“It's too early to say whether lowering sodium in the diet can reduce the severity or risk of developing eczema,” he said. Karsten Flor At King's College London.

Abuaballah said her team will soon begin enrolling participants for a National Institutes of Health-funded study that will look at the relationship between dietary sodium, sodium levels on the skin, and eczema severity.

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Source: www.newscientist.com

Greenland’s melting ice could trigger a heat wave in Europe this year

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Melting ice in Greenland could worsen extreme weather across Europe

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Europe's 10 hottest and driest summers in the past 40 years have all come after a particularly large amount of fresh water was released from the Greenland ice sheet, meaning southern Europe will experience an especially hot summer this year. Maybe you are doing it.

They say this link occurs because the excess meltwater triggers a series of amplifying feedbacks that affect the strength and position of the atmospheric jet stream over Europe. Marilena Ortmans At the UK National Marine Centre.

“2018 and 2022 were the most recent examples,” she says. 2022 saw extreme heat and numerous bushfires across Europe, with high temperatures reaching 40°C (104°F) in parts of the UK for the first time.

These feedback effects, on top of the underlying warming trend from fossil fuel emissions, mean Europe will become even hotter and drier in coming decades as the melting of the Greenland ice sheet accelerates. Then Mr. Ortmans says:

“This is on top of the warming that is already happening due to increases in greenhouse gases,” she says.

Hotter heat waves and drier droughts are expected as the planet warms, but in some regions, such as Europe, recent heat waves and droughts have been even more extreme than climate modeling projects. Several studies have linked these extreme events to changes in the strength and position of the Arctic jet stream. The Arctic jet stream is a band of upper-level winds whose location and strength have a significant impact on weather.

But it's not clear what causes these changes, Ortmans says. Now, she and her colleagues are analyzing weather observations from the past 40 years, and the results show that extreme weather is ultimately the result of a period of increased ice melt in Greenland. It is said that there is.

“Observational statistical associations are very powerful,” she says.

The excess meltwater leads to a shallow layer of freshwater that extends south of the North Atlantic Ocean. This layer does not easily mix with the warm, salty ocean water below, causing the ocean surface to be colder than normal in winter.

This makes the gradient between this colder water and warmer water further south even more extreme, strengthening the weather front aloft. As a result, wind patterns strengthen, pushing warm water flowing northward, the North Atlantic Current, further north than usual. This further amplifies the temperature gradient.

“The front that forms between an area of ​​cold fresh water and an area of ​​warm ocean water is the main source of energy for storms,” ​​she says.

In a 2020 study, Ortmans suggested: This process leads to an increase in storms. during one winter.

Now, Oltmans' team suggests that these winter changes have lasting effects into the following summer. “Two years after the freshwater anomaly occurred, we are still seeing significant signs,” she says.

The researchers found that stronger temperature gradients lead to stronger jet streams across Europe, making the weather in southern Europe even hotter and drier. Then, as the unusually cold water recedes, the jet stream moves north, bringing hot, dry weather to northern Europe.

“We have discussed the individual links in this feedback chain before,” Ortmans says. “What we did in this study is bring these links together.”

Computer models miss this chain of feedback because they don't include factors such as large fluctuations in meltwater from year to year, she says.

“The association between Atlantic freshwater anomalies and subsequent European summer weather proposed in this study is interesting and relevant to current scientific research on long-term predictions of summer weather, especially “If that relationship holds true for future summers,” he says. adam scaife He works on long-term forecasts at the UK Met Office.

“I think this study is somewhat convincing,” he says. Fei Luo At the Singapore Climate Research Center. But when it comes to predicting summer weather, looking at the previous year's snowmelt isn't as helpful as looking at winter weather conditions, Luo said.

But Oltmans is confident enough to predict that Europe will experience more heatwaves and droughts in the coming years as Greenland's ice melts further in the summer of 2023. “I think southern Europe will experience strong heat anomalies this summer,” she says.

These are likely to become even more powerful in 2025, after which they will begin to impact Northern Europe. “We expect Northern Europe to experience another strong heatwave and drought, not this year, but in the next few years.”

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Source: www.newscientist.com