Perivascular spaces are involved in clearing waste and toxins from the brain and may be associated with the brain changes associated with aging.

The study involved 414 people with an average age of 80. Participants took cognitive tests of thinking and memory skills and were assessed for the presence of dementia at the beginning of the study and every two years for eight years. The participants had MRI brain scans to check for enlarged perivascular spaces in two key areas of the brain at the start of the study and then every two years for eight years. The top quarter of the people with the largest number of enlarged perivascular spaces, designated as severe cases, were compared to those with fewer or no enlarged spaces.

“Severe perivascular space disease may be a marker for an increased risk of cognitive decline and dementia,” said study author Matthew Paradise, MB.Ch.B., M.Sc., of the University of New South Wales in Sydney, Australia. “More research is needed to understand how these enlarged spaces develop, as they could be an important potential biomarker to help with early diagnosis of dementia.”

Researchers found that people with the largest number of enlarged perivascular spaces in both areas of the brain were nearly three times more likely to develop dementia during the study than people with fewer or no enlarged spaces.

A total of 97 people, or 24%, were diagnosed with dementia during the study. Of the 31 people with severe cases in both areas of the brain, 12 people, or 39%, were diagnosed with dementia.

The people with severe enlargement of perivascular spaces in both areas of the brain were also more likely to have greater decline four years later on their overall scores of cognition than the people with mild or absent enlargement of spaces.

The results persisted after researchers adjusted for other factors that could affect either scores on tests or the development of dementia, such as age, high blood pressure and diabetes. The researchers also took into account other signs of disease in the small blood vessels in the brain, which can also be a sign of risk of dementia.

“These results suggest that there is an independent mechanism for the perivascular spaces as a biomarker of cognitive impairment and dementia apart from being a general marker of disease in the small vessels,” Paradise said. “For example, enlarged perivascular spaces may be a biomarker of impaired waste clearance in the brain.”

Paradise noted that the study does not prove that enlarged perivascular spaces cause these thinking and memory problems over time; it only shows an association.

Limitations of the study include that cognitive test data was only available over four years and that imaging data could have missed some enlarged perivascular spaces in the brain.

The study was supported by the Australian National Health and Medical Research Council and the Josh Woolfson Memorial Scholarship.

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As described in the journal Sciences Advances today [27 January], researchers from Bristol’s School of Earth Sciences were able to document the decay process of eukaryotic algal cells, showing that nuclei, chloroplasts and pyrenoids (organelles found within chloroplasts) can persist for weeks and months after cell death in eukaryote cells, long enough to be preserved as fossils.

Emily Carlisle, a PhD student from Bristol’s School of Earth Sciences and co-author, was able to characterise the transformation of the organelles into something resembling snot. She said: “I spent several weeks photographing algal cells as they decayed, checking the condition of the nuclei, chloroplasts and pyrenoids. From this, we could tell that these organelles don’t decay immediately after cell death, but actually take many weeks to dissolve.”

When life first appeared on Earth it was limited to simple bacteria. Two billion years later, complex life emerged in the form of large eukaryote cells with membrane-bound organelles, such as a nucleus and chloroplasts. The evolution of fungi, plants and animals followed.

However, precisely when complex life emerged has proved difficult to say. Previous genomic studies suggested that eukaryote cells could have evolved anywhere from 800 million to 1,800 million years ago, an imprecise range that needs fossils to narrow it down.

“The evolution of eukaryotes was a hugely important event in the history of life on Earth, but fossils of these cells are difficult to interpret,” said Professor Phil Donoghue, expert in molecular palaeobiology and one of the co-authors of the study. “Some of them have structures that could be organelles, but there’s long been this assumption that organelles cannot be preserved because they would decay too quickly.”

Although living eukaryotes include large forms that are easily spotted, early eukaryotes were predominantly single cells, difficult to distinguish from bacterial cells.

Historically, large size and intricate cell walls have been used to identify early eukaryotes, but some bacteria can attain large size, and cell wall decorations might be lost to the ravages of time and erosion. Organelles such as nuclei and chloroplasts are not found in bacteria, and would therefore be a definitive indicator of complex life, but they have been assumed to decay too quickly to be fossilised.

The results of these experiments shed light on the controversial fossils of early complex life that include structures within the cells. Dr John Cunningham, a Bristol co-author, said: “The structures in Shuiyousphaeridium, a fossil from 1,700 million years ago, closely resemble nuclei. This interpretation has previously been dismissed because of the assumed rapid decay of nuclei. Our decay experiments have shown that nuclei can persist for several weeks, meaning the structures in Shuiyousphaeridium are likely to be nuclei.”

By revealing the decay patterns of organelles, the study’s authors say they can demonstrate the presence of complex life to 1,700 million years ago, helping to elucidate their evolutionary history with greater precision and clarity.

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Precarious employment, or P.E., is defined as low-quality employment, which is often characterized by low wages, job insecurity and irregular hours, making employment risky and stressful for the worker.

In her study, “Changes in precarious employment in the United States: A longitudinal analysis,” Vanessa Oddo, assistant professor in UIC’s School of Applied Health Sciences, sought to create a multidimensional and continuous measure of P.E. in the U.S. She also set out to describe changes in precarious employment over time, both overall and within subgroups. The paper is published in the Scandinavian Journal of Work, Environment & Health.

A better understanding of long-term trends is a critical first step for informing future policies aimed at improving P.E. and population health in the U.S., Oddo said.

Previously, the focus for measuring P.E. was on wages, hours and union membership. For this longitudinal study, she expanded the measurement criteria to add P.E. indicators including:

Material rewards — the wage and non-wage benefits afforded by employment.

Working-time arrangements — the length and intensity of working hours, underemployment and schedule predictability.

Employment stability — employment continuity, contractual temporariness and/or organizational changes (e.g., downsizing).

Workers’ rights — describes welfare state provisions associated with employment, such as access to health insurance or pensions.

Collective organization — the possibilities (or lack thereof) for employee representation, most commonly measured through union representation.

Interpersonal relations — employees’ power relative to management (e.g., their ability to make decisions or control their schedule) and can include exposure to discrimination.

Training opportunities — opportunities for promotion or to enhance skills.

Characterizing trends in P.E. using a multidimensional indicator is critical given that employment quality is increasingly recognized as a social determinant of health, according to Oddo.

P.E. can result in insufficient income, which compromises access to food and other necessities; greater exposure to adverse physical working conditions, such as toxic exposure, and limited control over both personal and professional lives, leading to stress.

“Importantly, poor employment quality may be contributing to widening health inequities, as women, people with lower education levels, and minorities have a higher prevalence of P.E.,” Oddo said.

The research revealed P.E. score was significantly higher among people of color, women, people with lower levels of education and people with lower income. Between 1988 and 2016, the overall P.E. scores significantly increased indicating worsening employment quality over time.

However, the study showed the largest increases in P.E. among males, people with a college education, and higher-income individuals.

“These results suggest long-term decreases in employment quality are widespread in the U.S., rather than just confined to marginalized segments of the labor market,” Oddo said.

According to the study, the largest change over time in employment precarity among males and college-educated and higher-income individuals could be because their P.E. score was lower at the study’s beginning in 1988, leaving a greater opportunity for declines. Additionally, the large increase in P.E. among males may also be due to the declining rate of union membership in the U.S., as union membership is associated with better employment quality and, historically, was more common among males.

Oddo said P.E. has been studied more broadly after the 2008 recession when employment quality worsened and there was a notable shift toward contract work and the emergence of the gig economy. She added that there is speculation as to how the COVID-19 pandemic will affect P.E., both during the pandemic and after when work from home measures are lifted.

A holistic approach to studying P.E. is important in the future as data can inform employment policy decisions. For example, a better understanding of P.E. in the U.S. may be helpful for informing future policies around secure scheduling (i.e. advanced notice of schedules) or gig work, like California’s Assembly Bill 5, which changed the rules employers must use to determine whether workers are employees or independent. The distinction is important because independent contractors are not entitled to?most of the protections and benefits?that employees get, Oddo explained.

Also, precarious employment could slow our ability to get back to work after COVID-19, as precariously employed individuals could face additional barriers to COVID-19 vaccination; for example, if they are undocumented workers or independent contractors.

One approach, which was approved by the Environmental Protection Agency in May, will release more than 750 million genetically modified mosquitos into the Florida Keys in 2021 and 2022. These “suicide mosquitoes” are genetically-altered to produce offspring that die before emerging into adults and therefore cannot bite humans and spread disease.

However, wiping out future generations of mosquitoes may cause environmental complications, such as potentially disrupting food chains. A new research study at the University of Missouri offers another option: genetically modifying mosquitoes to be resistant to Zika virus altogether.

Alexander Franz, an associate professor in the MU College of Veterinary Medicine, collaborated with researchers at Colorado State University by using CRISPR gene-editing technology to produce mosquitoes that are unable to replicate Zika virus and therefore cannot infect a human through biting.

“We genetically manipulated these mosquitoes by inserting an artificial gene into their genome that triggers one of the immune pathways in the midgut to recognize and destroy the RNA genome of Zika virus,” Franz said. “By developing these mosquitoes that are resistant to the virus, the disease cycle is interrupted so transmission to humans can no longer take place.”

Franz added that the genetic modification is inheritable, so future generations of the altered mosquitoes would be resistant to Zika virus as well.

“We are interested in strategies for controlling insect vectors like mosquitoes that transmit various viruses affecting human health,” Franz said. “Public health experts suggest having a toolbox with different approaches available to tackle a virus such as Zika, and unfortunately right now there are limited options. There is no vaccine for the Zika virus widely available and spraying insecticides has become ineffective since the mosquitoes can develop resistance, so we are simply trying to expand the toolbox and provide a solution by genetically modifying the mosquitoes to become Zika-resistant while keeping them alive at the same time.”

Franz’ research is designed to help prevent another outbreak of Zika virus disease from occurring.

“If you can ever find a way to block the transmission of a pathogen that negatively affects humans, that is good news,” Franz said. “We have shown this is a viable option for genetically modifying mosquitos in a lab setting. There would need to be thorough discussions about regulatory compliance to see if this can be a solution out in the field down the road, and who knows when another Zika outbreak might happen in the future, which is why this research is so important.”

The study was funded by the National Institutes of Health.

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Humans have been breeding corn to make it more useful for thousands of years. Jackson says:

“Ten thousand years ago, corn did not exist, right? There was a wild plant called teosinte. Teosinte itself only makes about 10 seeds. It makes these really tiny ears that don’t give much nutrition. In fact, the seeds they make are so tough that they would break your teeth if you try to eat them anyway.”

The secret to more and bigger kernels is found by looking at baby ears of corn 1-10 mm long. The scientists used a technique that allowed them to track every cell. They gave each cell a genetic ID tag, called a barcode. Xiaosa Xu, the lead author of the study, compares it to building a building. Xu says:

“We are able to use this single-cell RNA-seq technology to identify which block is what kind of identity: if this block is from our kitchen room or that block is from our bedroom.”

The scientists took corn plants at early stages of development, broke them into individual cells, barcoded them, and then saw what genes were turned on in each one. Jackson notes, “in the past we haven’t been able to separate the cells and figure out the genetic information that’s specific to each cell. So that’s really, what’s new and exciting.” They could then reconstruct an anatomical map to pinpoint where genes important for corn development were used.

Crops are still evolving. Jackson looks forward to developing different kinds of corn plants to fill new ecological niches. He also hopes this new technique will help other plant geneticists in their efforts to sustainably improve crop yields.

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Materials provided by Cold Spring Harbor Laboratory. Original written by Luis Sandoval. Note: Content may be edited for style and length.

“Whenever there is a large volcanic eruption, there is a chance that if a flank of the volcano is unstable there could be a collapse,” said Judit Gonzalez-Santana, a doctoral student in the Department of Geosciences. “To better explore this hazard, we applied an increasingly popular and more sensitive time-series method to look at these movements, or surface deformation, over longer time periods.”

Using the time-series technique, the scientists found surface deformation related to flank motion had occurred at Pacaya, an active volcano in Guatemala, from 2011 to 2013 when the volcano was largely quiet, and increased leading up to an eruption in 2014. Previous work had not identified flank motion during this time, the scientists said.

“People have looked at that volcano with satellite remote sensing but did not detect this long-term flank motion or creep,” said Christelle Wauthier, associate professor of geosciences. “Because the surface deformation changes are pretty small per year, it can easily be below the detection limits of conventional methods, but still within the limits of Judit’s work using a time-series approach.”

Scientists track surface deformation using radar satellites sensitive enough to spot changes of just a few inches on the ground. Comparing two of these images using the conventional Interferometric Synthetic Aperture Radar (InSAR) technique creates an interferogram, essentially a map of surface movement. But the quality of the InSAR results decreases with the time separating two images and can be affected by even small changes, like from vegetation growth or a buildup of ash spewed from a volcano, the scientists said.

The team instead conducted an InSAR time-series analysis using hundreds of satellite images taken over years and identifying surface deformation between each.

“You can use many of these short-term surface movement maps to give you information of surface displacement over a long time period,” Gonzalez-Santana said. “Then you can look at the surface deformation maps and see how much each pixel has been moving since the date the first image was acquired, for example.”

The results, published in the Journal of Volcanology and Geothermal Research, provide finer detail of volcanic flank motion, and can reveal upticks in the rate that creep is occurring, like at Pacaya before the eruption in 2014, the scientists said. The team has shared the results with officials in Guatemala who monitor the volcano.

“This kind of creep is not uncommon and not particularly dangerous on its own, but if you have extra forcings like from magma being pressurized and pushing against the wall of the chamber or intrusion, it can trigger a catastrophic collapse,” Wauthier said. “To be able to understand the behavior of the instability and potentially detect changes in rates of motion is very critical for monitoring that potential collapse.”

The method shows promise for identifying deformation particularly at volcanoes that lack expensive real-time monitoring networks and those located in tropical areas with thick vegetation that create problems for traditional InSAR, the scientists said.

Flank instability is often studied at oceanic volcanoes, where a collapse could trigger a deadly tsunami, according to the scientists. But collapses also happen inland, including prominently at Mount St. Helens in 1980.

Pacaya itself experienced a collapse sometime around 1,000 years ago, creating a debris avalanche that traveled more than 15 miles, and leaving a prominent scar on the volcano. Subsequent eruptions have built the volcano back up and it could someday again collapse, the scientists said.

“More than 10,000 people live within about three miles of the volcano,” Gonzalez-Santana said. “If you take into consideration the last avalanche traveled 15 miles away, anyone living in the valleys around the volcano could be at risk.”

A NASA Earth Surface and Interior grant, a Future Investigators in NASA Earth and Space Science and Technology grant, and an Institute for Computational and Data Sciences seed grant funded this research.

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Materials provided by Penn State. Original written by Matthew Carroll. Note: Content may be edited for style and length.