Guided by previous research of spider brains, the scientists uncovered evidence of a “waste canal system” in the human brain that internalizes waste from healthy neurons. They discovered that this system can undergo catastrophic swelling, which leads to the degeneration of brain tissue, a hallmark of Alzheimer’s disease.

With over 50 million affected people worldwide, Alzheimer’s disease is among the leading causes of death in the U.S.

The findings, which have been published by The Journal of Comparative Neurology, offer a compelling new explanation for commonly described brain pathologies observed in Alzheimer’s disease, including amyloid-beta plaques, tau tangles, and spongiform abnormalities.

Supported by the Vermont Biomedical Research Network (VBRN), the research was carried out in collaboration among Dr. Ruth Fabian-Fine (Saint Michael’s College, UVM Robert Larner, M.D. College of Medicine), Dr. John DeWitt (UVM Robert Larner, M.D. College of Medicine, UVM Medical Center), Dr. Adam Weaver (Saint Michael’s College), and Saint Michael’s undergraduate research students Abigail Roman and Melanie Winters, both members of the Class of 2025.

“The Vermont Biomedical Network has been thrilled to support Dr. Fabian-Fine’s research from its initial focus on animal neuroscience to the more recent and potentially groundbreaking emphasis on the cellular basis of human neurodegeneration,” said UVM’s Dr. Christopher Francklyn, the Director of VBRN. “Her exciting work, and the outstanding training she has provided to her undergraduate co-investigators, epitomizes what NIH hopes to accomplish with its national IDEA program.”

Neuroscientist Dr. Fabian-Fine and her team initially investigated the underlying causes for neurodegeneration in Central American wandering spiders that suffer from conditions similar to degenerative diseases in humans. Because the spider neurons were a larger size, the scientists were better able to observe their brain functions. They quickly discovered a waste-internalizing glial canal system that undergoes structural abnormalities in degenerating spider brains, which leads to uncontrolled depletion and death of brain cells.

This discovery prompted Fabian-Fine, a Vermont Center for Cardiovascular and Brain Health Pipeline Investigator, to explore whether a similar system could be found in both rodent and human brain tissue, so she teamed up with neuropathologist Dr. DeWitt at UVM’s Larner College of Medicine. The collaborative undertaking led the scientists to gather overwhelming evidence that neurodegeneration in human and rodent brains may have similar underlying causes compared to those observed in spider brains. The scientists’ report outlines possible underlying causes for neurodegeneration that may offer a promising new avenue for drug development that can address the structural abnormalities that lead to neurodegeneration.

Dozens of student researchers at Saint Michael’s College contributed to the multi-year research that provided the foundation for this breakthrough. Experiments occurred at Saint Michael’s College, the University of Vermont Medical Center, and at the UVM’s Center for Biomedical Shared Resources.

Further, the results of the study by Oregon Health & Science University involving neurosurgery patients suggests new possibilities for tapping into those areas to improve learning among people bedeviled by math.

“This work lays the foundation to deeper understanding of number, math and symbol cognition — something that is uniquely human,” said senior author Ahmed Raslan, M.D., professor and chair of neurological surgery in the OHSU School of Medicine. “The implications are far-reaching.”

The study published today in the journal PLOS ONE.

Raslan and co-authors recruited 13 people with epilepsy who were undergoing a commonly used surgical intervention to map the exact location within their brains where seizures originate, a procedure known as stereotactic electroencephalography. During the procedure, researchers asked the patients a series of questions that prompted them to think about numbers as symbols (for example, 3), as words (“three”) and as concepts (a series of three dots).

As the patients responded, researchers found activity in a surprising place: the putamen.

Located deep within the basal ganglia above the brain stem, the putamen is an area of the brain primarily associated with elemental functions, such as movement, and some cognitive function, but rarely with higher-order aspects of human intelligence like solving calculus. Neuroscientists typically ascribe consciousness and abstract thought to the cerebral cortex, which evolved later in human evolution and wraps around the brain’s outer layer in folded gray matter.

“That likely means the human ability to process numbers is something that we acquired early during evolution,” Raslan said. “There is something deeper in the brain that gives us this capacity to leap to where we are today.”

Researchers also found activity as expected in regions of the brain that encode visual and auditory inputs, as well as the parietal lobe, which is known to be involved in numerical and calculation-related functions.

From a practical standpoint, the findings could prove useful in avoiding important areas during surgeries to remove tumors or epilepsy focal points, or in placing neurostimulators designed to stop seizures.

“Brain areas involved in processing numbers can be delineated and extra care taken to avoid damaging these areas during neurosurgical interventions,” said lead author Alexander Rockhill, Ph.D., a postdoctoral researcher in Raslan’s lab.

Researchers credited the patients involved in the study.

“We are extremely grateful to our epilepsy patients for their willingness to participate in this research,” said co-author Christian Lopez Ramos, M.D., a neurosurgical resident at OHSU. “Their involvement in answering our questions during surgery turned out to be the key to advancing scientific understanding about how our brain evolved in the deep past and how it works today.”

Indeed, the study follows previous lines of research involving mapping of the human brain during surgery.

“I have access to the most valuable human data in nature,” Raslan said. “It would be a shame to miss an opportunity to understand how the brain and mind function. All we have to do is ask the right questions.”

In the next stage of this line of research, Raslan anticipates discerning areas of the brain capable of performing other higher-level functions.

In addition to Raslan, Rockhill and Lopez Ramos, co-authors include Hao Tan, M.D., Beck Shafie, Maryam Shahin, M.D., Adeline Fecker, Mostafa Ismail, Daniel Cleary, M.D., and Kelly Collins, M.D., of OHSU; and Caleb Nerison, D.O., now of Lexington Medical Center in South Carolina.

Combining two materials that selectively absorb short and long wavelengths, e.g., blue/green and red/infrared parts of the spectrum, makes the best use of our sunlight and is a well-known strategy to increase efficiency in solar cells. Best red/infrared absorbing parts of solar cells so far were, however, made from traditional materials, such as silicon or CIGS (copper indium gallium selenide). Unfortunately, these require high processing temperatures, and thus exhibit a relatively high carbon footprint.

In their work, now published in Nature, Lang and colleagues combine two emerging solar cell technologies, namely perovskite and organic solar cells, that both are processed at low temperatures with a low carbon footprint. Achieving a record level of 25.7 % efficiency for this new combination, however, was not easy, says Felix Lang: “This was only possible by combining two major breakthroughs.” First, Meng and Li synthesized a novel red/infrared absorbing organic solar cell that extends its absorption even further into the infrared. “Still, tandem solar cells were limited by the perovskite layer, which shows strong efficiency losses if adjusted to absorb only blue/green parts of the sun spectrum,” he explains. “To tackle this, we utilized a novel passivation layer applied to the perovskite that reduces material defects and improves the performance of the whole cell.”

The incidence of kidney cancer in the United States rose by an average of 1.2 percent each year between 2011 and 2019 to become the seventh most common cancer. In the meantime, smoking — a well-established risk factor for kidney cancer — has continued to decline.

This led researchers to consider other possible contributing factors, including arsenic, a known cause of various cancers that is naturally occurring in groundwater in Texas and other areas. Unlike previous studies, the Texas A&M study focused on low levels of arsenic exposure (below the regulatory threshold of 10 parts per billion) in both public water systems, which are regulated by various government agencies, and private well systems, which are not regulated.

“Some public water systems are poorly managed and could expose customers to arsenic, but the 40 million people in the United States who rely on private wells are particularly vulnerable,” said Taehyun Roh, with the Department of Epidemiology and Biostatistics.

Others involved with the study were Daikwon Han, Xiaohui Xu, and then-doctoral student Nishat Tasnim Hasan, with the Department of Epidemiology and Biostatistics, and Garett Sansom, with the Department of Environmental and Occupational Health. The project was supported by grants from the Houston Methodist Research Institute, Robert and Janice McNair Foundation and National Institute of Environmental Health Sciences.

Their findings, published in Environmental Pollution, examined the relationship between kidney cancer rates and arsenic levels in drinking water across 240 Texas counties. The team analyzed cancer data from the Surveillance, Epidemiology, and End Results on 28,896 cases of cancer among adults in Texas aged 20 and older, alongside water testing data from the Texas Department of State Health Services and the Texas Water Development Board.

They used a statistical model that accounts for geographic location and adjusted the model for demographic and socioeconomic factors and cancer risk factors such as obesity, smoking and diabetes. They also adjusted for covariates that included pesticide density, social vulnerability, income level, rurality, cardiovascular disease hospitalization rates and the prevalence of chronic kidney disease.

The analysis found that exposure to between 1 and 5 parts per billion raised kidney cancer risk by 6 percent, and exposure above 5 parts per billion raised the risk by 22 percent. In addition, the risk of cancer increased by 4 percent with each doubling of water arsenic levels.

“This suggests that even low-level arsenic exposure in drinking water may be associated with an increased risk of kidney cancer, which aligns with previous research indicating an association between this exposure and lung, bladder and skin cancers,” Roh said.

Hasan noted that their study design can indicate associations between factors but not causality and recommended that future studies focus on individual-level and biometric data — rather than the county-level data used here — to better assess the effects of factors such as lifestyle, family history of kidney cancer and other possible sources of arsenic exposure.

“Still, our findings indicate that reducing arsenic exposure could reduce the incidence of kidney cancer, and this could be achieved through efforts such as enhanced regulatory oversight and targeted public health interventions,” Hasan said.

The international team of scientists buried 19,000 bags of green tea and rooibos in 180 wetlands across 28 countries to measure the ability for wetlands to hold carbon in their soil, known as wetland carbon sequestration.

While tea bags may seem an unusual instrument to measure this phenomenon, it is a proven proxy method to measure carbon release from soil into the atmosphere. However, this is the first time teabags have been used for a large-scale, long-term study and the tea leaves have revealed which types of wetlands are leaking the most carbon.

RMIT University’s Dr Stacey Trevathan-Tackett led the study published in Environmental Science and Technology as part of an Australian Research Council DECRA Fellowship while at Deakin University.

The global study involved 110 co-authors on the paper, along with many others who helped such as undergraduate students and citizen scientists. Core team members included Dr Martino Malerba and Professor Peter Macreadie from Deakin University and RMIT, Dr Sebastian Kepfer-Rojas from the University of Copenhagen in Denmark and Dr Ika Djukic from The Swiss Federal Institute for Forest, Snow and Landscape Research WSL.

“This is the first long-term study of its kind, using this tea bags method, which will help guide how we can maximise carbon storage in wetlands and help lower emissions globally,” said Trevathan-Tackett, who is now in RMIT’s School of Science.

“Changes in carbon sinks can significantly influence global warming — the less carbon decomposed means more carbon stored and less carbon in the atmosphere.”

Reading the tea leaves

Tea bags provide a simple and standardised way to identify how climate, habitat type and soil type influence carbon breakdown rates in wetlands.

At each site, scientists buried between 40 and 80 tea bags about 15 cm underground and collected these at various time intervals over three years, tagging their GPS location. They then measured their remaining organic mass to assess how much carbon had been preserved in the wetlands.

The project used the two types of tea bags (green and rooibos) as measures for different kinds of organic matter found in soils. Green tea consists of organic matter that decomposes easily, whereas rooibos decomposes more slowly. Using both types of tea bags in this project enabled the researchers to gain a more comprehensive picture of the wetlands’ capacity for carbon storage.

“This data shows us how we can maximise carbon storage in wetlands globally,” Trevathan-Tackett said.

The findings

The team studied the effect of temperature in two ways: using local weather station data for each site and comparing differences in climate regions.

“Generally, warmer temperatures led to increased decay of organic matter, which translates to reduced carbon preservation in soil,” Trevathan-Tackett said.

The two tea types acted differently with increasing temperature.

“For the harder to degrade rooibos tea, it didn’t matter where it was — higher temperature always led to more decay, which indicates that types of carbon we’d typically expect to see last longer in the soil were vulnerable to higher temperatures,” Trevathan-Tackett said.

“With increasing temperatures, the green tea bags decayed at different rates depending on the type of wetland — it was faster in freshwater wetlands but slower in mangrove and seagrass wetlands.

“Increasing temperatures may also help boost carbon production and storage in plants, which could help offset carbon losses in wetlands due to warmer weather, but this warrants further investigation with future studies.”

Freshwater wetlands and tidal marshes had the highest tea mass remaining, indicating a greater potential for carbon storage in these ecosystems.

The study’s findings are helping piece together the puzzle of wetland carbon sequestration on a global scale. Within the terrestrial TeaComposition initiative led by Djukic, information on litter decomposition has been collected at about 500 sites worldwide resulting in several peer-review publications.

“Applying the common metric across aquatic, wetland, marine and terrestrial ecosystems allows for a conceptual comparison and understanding of key drivers involved in the control of global litter carbon turnover,” Djukic said.

“Now that we are starting to get a better understanding of which environments are storing more carbon than others, we can use this information to ensure we protect these areas from environmental or land-use change.”

Next steps

The researchers will combine the data from this project with data from similar studies of land-based carbon sinks, including forests, to inform designs of predictive global models.