Sleeping With the Light On May Be Harmful To You

“Exposure to even moderate ambient lighting during nighttime sleep, compared to sleeping in a dimly lit room, harms your cardiovascular function during sleep and increases your insulin resistance the following morning,” announced Northwestern Medicine, citing a new study recently published in the Proceedings of the National Academy of Sciences.

The Washington Post reports:
Researchers at Northwestern University had two groups of 10 young adults sleep in differently lit rooms. One group slept in rooms with dim light for two nights; the other slept one night in a room with dim night and the next in a room with moderate overhead light — about the equivalent of an overcast day. Participants wore heart monitors at night. In the morning, they did a variety of glucose tests.

Both groups got the same amount of sleep but their bodies experienced very different nights. Both groups responded well to insulin the first night, when they both slept in dim lighting. On the second night, however, the group sleeping in brighter lighting didn’t respond as well to insulin. The dim light sleepers’ insulin resistance scores fell about 4 percent on the second night, while the bright sleepers’ rose about 15 percent. Their heart rates were faster on the bright night, too.

“[J]ust a single night of exposure to moderate room lighting during sleep can impair glucose and cardiovascular regulation, which are risk factors for heart disease, diabetes and metabolic syndrome,” concludes senior study author Dr. Phyllis Zee. “It’s important for people to avoid or minimize the amount of light exposure during sleep.”
From Northwestern’s announcement:
There is already evidence that light exposure during daytime increases heart rate via activation of the sympathetic nervous system, which kicks your heart into high gear and heightens alertness to meet the challenges of the day. “Our results indicate that a similar effect is also present when exposure to light occurs during nighttime sleep,” Zee said….

An earlier study published in JAMA Internal Medicine looked at a large population of healthy people who had exposure to light during sleep. They were more overweight and obese, Zee said. “Now we are showing a mechanism that might be fundamental to explain why this happens. We show it’s affecting your ability to regulate glucose,” Zee said.

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Researchers Discover a New (intermediate and Tetragonal) Form of Ice

Researchers at the University of Nevada, Las Vegas were trying to understand how water might behave under the high pressures inside distant planets.
But along the way the team discovered a new form of ice, reports, “redefining the properties of water at high pressures.”

Solid water, or ice, is like many other materials in that it can form different solid materials based on variable temperature and pressure conditions, like carbon forming diamond or graphite. However, water is exceptional in this aspect as there are at least 20 solid forms of ice known to us.

A team of scientists working in UNLV’s Nevada Extreme Conditions Lab pioneered a new method for measuring the properties of water under high pressure. The water sample was first squeezed between the tips of two opposite-facing diamonds — freezing into several jumbled ice crystals. The ice was then subjected to a laser-heating technique that temporarily melted it before it quickly re-formed into a powder-like collection of tiny crystals. By incrementally raising the pressure, and periodically blasting it with the laser beam, the team observed the water ice make the transition from a known cubic phase, Ice-VII, to the newly discovered intermediate, and tetragonal, phase, Ice-VIIt, before settling into another known phase, Ice-X….

While it’s unlikely we’ll find this new phase of ice anywhere on the surface of Earth, it is likely a common ingredient within the mantle of Earth as well as in large moons and water-rich planets outside of our solar system. The team’s findings were reported in the March 17 issue of the journal Physical Review B…. The work also recalibrates our understanding of the composition of exoplanets, UNLV physicist Ashkan Salamat added. Researchers hypothesize that the Ice-VIIt phase of ice could exist in abundance in the crust and upper mantle of expected water-rich planets outside of our solar system, meaning they could have conditions habitable for life.

Thanks to long-time Slashdot reader fahrbot-bot for sharing the story…

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Brain-Imaging Studies Hampered by Small Data Sets, Study Finds

For two decades, researchers have used brain-imaging technology to try to identify how the structure and function of a person’s brain connects to a range of mental-health ailments, from anxiety and depression to suicidal tendencies. But a new paper, published Wednesday in Nature, calls into question whether much of this research is actually yielding valid findings. The New York Times reports: Many such studies, the paper’s authors found, tend to include fewer than two dozen participants, far shy of the number needed to generate reliable results. “You need thousands of individuals,” said Scott Marek, a psychiatric researcher at the Washington University School of Medicine in St. Louis and an author of the paper. He described the finding as a “gut punch” for the typical studies that use imaging to try to better understand mental health.

Studies that use magnetic-resonance imaging technology commonly temper their conclusions with a cautionary statement noting the small sample size. But enlisting participants can be time-consuming and expensive, ranging from $600 to $2,000 an hour, said Dr. Nico Dosenbach, a neurologist at Washington University School of Medicine and another author on the paper. The median number of subjects in mental-health-related studies that use brain imaging is around 23, he added. But the Nature paper demonstrates that the data drawn from just two dozen subjects is generally insufficient to be reliable and can in fact yield ‘massively inflated’ findings,” Dr. Dosenbach said. The findings from the Nature paper can “absolutely” be applied to other fields beyond mental health, said Marek. “My hunch this is much more about population science than it is about any one of those fields,” he said.

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Protein Tweak Makes CRISPR Gene Editing 4,000 Times Less Error-Prone

Researchers at the University of Texas at Austin have identified a previously unknown structure of the protein that’s responsible for making edits to the wrong sections of DNA. After some tweaking, they were able to reduce the likelihood of off-target mutations by 4,000 times. New Atlas reports: CRISPR tools use certain proteins, most often Cas9, to make precise edits to specific DNA sequences in living cells. This can involve cutting out problematic genes, such as those that cause disease, and/or slotting in beneficial ones. The problem is that sometimes the tool can make changes to the wrong parts, potentially triggering a range of other health issues. And in the new study, the UT researchers discovered how some of these errors can happen. Usually, the Cas9 protein is hunting for a specific sequence of 20 letters in the DNA code, but if it finds one where 18 out of 20 match its target, it might make its edit anyway. To find out why this occurs, the team used cryo-electron microscopy to observe what Cas9 is doing when it interacts with a mismatched sequence.

To their surprise, they discovered a strange finger-like structure that had never been observed before. This finger reached out and stabilized the DNA sequence so the protein could still make its edit. Having uncovered this mechanism, the team tweaked this finger so that it no longer stabilized the DNA, instead pushing away from it. That prevents Cas9 from editing that sequence, making the tool 4,000 times less likely to produce off-target mutations. The team calls the new protein SuperFi-Cas9. The research was published in the journal Nature.

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Scientists Demonstrate Self-Awareness In Fish

Researchers from the Graduate School of Science, Osaka City University, have provided evidence to suggest that fish have the capacity for MSR, a behavioral test to determine whether an animal possesses the ability of visual self-recognition. As Phys.Org explains, an animal’s capacity for MSR is determined when they “touch or scrape a mark placed on their body in a location that can only be indirectly viewed in a mirror.” From the report: Professor [Masanori Kohda] says, “Previously, using a brown marking on the throat area of [cleaner fish Labroides dimidiatus], we had shown three out of four cleaner fish to scrape their throats several times after swimming in front of a mirror, a number on par with similar studies done on other animals like elephants, dolphins, and magpies.” However, one of the criticisms laid against this result was sample size and the need for repeated studies showing positive results. Teaming up with researchers from the Max Planck Institute of Animal Behavior in Germany and the University of Neuchatel in Switzerland, this study increased the sample size to 18 cleaner fish, with a 94% positive result of 17 of them demonstrating the same behavior from the previous study.
Prof. Kohda says, “Our previous study demonstrated MSR in L. dimidiatus; however, studies with other animals have shown that simply moving a mirror reignites aggressive behavior, suggesting the animal has only learned a spatial contingency, not MSR.” To address this, the team transferred mirror-trained cleaner fish to a tank with a mirror on one side of the tank and then three days later to a tank with a mirror on the other side, and saw the fish show no aggression toward their mirror image in both tanks. Also, to ensure the L. dimidiatus that passed the mark test truly are recognizing themselves, they placed mirror-trained fish in adjacent tanks that were separated by transparent glass. After two to three days, when fish largely reduced their aggressive behavior towards each other, they were marked the standard way the following night. None of the fish scraped their throat during the 120 mins of exposure to each other the following morning. This new experiment was recently published in PLOS Biology.

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Kombucha Cultures Make Excellent Sustainable Water Filters, Study Finds

Long-time Slashdot reader shoor shares a report from Ars Technica: The refreshing kombucha tea that’s all the rage these days among certain global demographics might also hold the key to affordable, environmentally sustainable living membranes for water filtration, according to a recent paper published in the American Chemical Society journal ACS ES&T Water. Experiments by researchers at Montana Technological University (MTU) and Arizona State University (ASU) showed that membranes grown from kombucha cultures were better at preventing the formation of biofilms — a significant challenge in water filtration — than current commercial membranes.

Co-author Katherine Zodrow, an environmental engineer at MTU, led an earlier 2020 study demonstrating the feasibility of making sustainable living filtration membranes (LFMs) out of a bacterial cellulose network and the native microorganisms of a kombucha SCOBY (symbiotic culture of bacteria and yeast) culture. Zodrow and her new collaborators made their membranes for this latest round of experiments the same way: by placing a SCOBY in a growth solution of sugar, black tea, and distilled white vinegar dissolved in deionized water. The researchers then placed the mixture in a temperature-controlled room for 10-12 days until a thick membrane formed on the mixture’s surface. The grown membranes were stored in deionized water and used in experiments within eight days. The 20 liters of raw water samples for the experiments were taken from the three drinking water treatment plants in Butte, Montana: Basin Creek Reservoir, Moulton Reservoir, and Big Hole River. The water samples were then pretreated in accordance with standard practices at each plant.

Both the LFMs and polymer-based filters, the researchers discovered, became clogged over time, causing them to flow and filter more slowly. The LFMs used in the experiments, however, showed between 19 and 40 percent better performance than their commercial counterparts on that score. The SCOBY-based LFMs were also more resistant to befouling. While biofilms eventually formed, fewer microorganisms were found in those films. Zodrow et al. sequenced the DNA of any bacteria and fungi in the SCOBY-based membrane and found that 97 percent of the bacteria present belonged to the genus Acetobacter. This is not surprising, since it’s also the dominant bacteria in kombucha, but it may explain why the LFMs performed so well with regard to biofilms. As the name implies, a defining characteristic of this genus is the ability to oxidize organic carbon sources like sucrose, glucose, and ethanol into acetic acid, which is known for its antimicrobial properties. Acetobacter has also been shown to reduce or even remove biofilms, in keeping with the results of Zodrow et al.’s experiments.

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Florida Manatees Facing Starvation to Be Fed in Trial Program

Wildlife officials in Florida are preparing to feed manatees in the wild, an unprecedented response to the animals’ mass starvation caused by the loss of seagrasses they normally eat. From a report: So far this year, 1,056 manatees have died in Florida, nearly double the average for the same period of the past five years, according to state data. While the record tally includes those killed by watercraft and other causes, malnourishment is the main reason propelling the increase, researchers say. The state’s total manatee population numbered at least 5,733 in 2019, the most recent year in which officials conducted a count. The U.S. Fish and Wildlife Service declared an “unusual mortality event” along Florida’s Atlantic coast this year — a designation indicating a significant die-off that demands an immediate response. The problem can worsen in the winter when the animals congregate in warmer waters that have become devoid of food, researchers say.

“The status of manatees going into this winter is so poor that without this supplemental feeding to help get them through, we’re going to have hundreds and hundreds of [them] dying,” said Patrick Rose, executive director of the advocacy group Save the Manatee Club. Seagrasses are disappearing because of deteriorating water quality caused by improperly treated sewage, leaking septic tanks and runoff containing fertilizer used for lawns and agriculture, researchers say. It’s part of a broader threat to other marine species, they say, and to Florida’s economy, which relies heavily on visitors drawn to the state’s coastline.

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