Category: science

Thiomargarita magnifica, a bacteria discovered on sunken red mangrove leaves in Guadeloupe, Lesser Antilles, has blown this standard scale out of the water. The species has evolved filamentary cells that are “larger than all other known giant bacteria by ~50-fold,” making them “visible to the naked eye,” according to a study published on Thursday in Science.
Scientists led by Jean-Marie Volland, a marine biologist who holds joint appointments at the Laboratory for Research in Complex Systems and the Joint Genome Institute (JGI), a U.S. Department of Energy office at Lawrence Berkeley National Laboratory, suspect that this record-breaking adaptation is partly due to the astonishing number of duplicated genes wielded by T. magnifica, an ability that is known as polyploidy. […]

The results revealed that these bacteria contain DNA clusters in their cells, which are located in compartments bordered by membranes that the team called “pepins.” These organized pepins provide a stark contrast to the free-floating DNA seen in the cells of most bacteria. In addition, the team’s genetic sequencing revealed that T. magnifica contains hundreds of thousands of genome copies that are dispersed across the cell, adding up to about three times the number of genes in most bacteria, which is an extreme example of polyploidy. “These cellular features likely allow the organism to grow to an unusually large size and circumvent some of the biophysical and bioenergetic limitations on growth,” Volland and his colleagues said.

Atom lasers that scientists have managed to achieve to date have been of the pulsed, rather than continuous variety; and involve firing off just one pulse before a new BEC needs to be generated. In order to create a continuous BEC, a team of researchers at the University of Amsterdam in the Netherlands realized something needed to change. “In previous experiments, the gradual cooling of atoms was all done in one place. In our setup, we decided to spread the cooling steps not over time, but in space: we make the atoms move while they progress through consecutive cooling steps,” explained physicist Florian Schreck. “In the end, ultracold atoms arrive at the heart of the experiment, where they can be used to form coherent matter waves in a BEC. But while these atoms are being used, new atoms are already on their way to replenish the BEC. In this way, we can keep the process going — essentially forever.” The research has been published in the journal Nature.

The research paper includes a description of the technology called focused rotary jet spinning, a process by which the biopolymer is produced, and quantitative assessments showing the coating extended the shelf life of avocados by 50 percent. The coating can be rinsed off with water and degrades in soil within three days, according to the study. […] The paper describes how the new fibers encapsulating the food are laced with naturally occurring antimicrobial ingredients — thyme oil, citric acid and nisin. Researchers in the Demokritou research team can program such smart materials to act as sensors, activating and destroying bacterial strains to ensure food will arrive untainted. This will address growing concern over food-borne illnesses as well as lower the incidence of food spoilage […].

“Every pharmaceutical we produce at some point or another has a palladium-catalysed step in it,” says Per-Ola Norrby, a pharmaceutical researcher at drug giant AstraZeneca in Gothenburg, Sweden. Palladium-catalysed reactions are so valuable that, in 2010, their discoverers shared a Nobel prize. But despite its versatility, chemists are trying to move away from palladium. The metal is more expensive than gold, and molecules that contain palladium can also be extremely toxic to humans and wildlife. Chemical manufacturers have to separate out all traces of palladium from their products and carefully dispose of the hazardous waste, which adds extra expense. Thomas Fuchb, a medicinal chemist at the life-sciences company Merck in Darmstadt, Germany, gives the example of a reaction to make 3 kilograms of a drug molecule for which the ingredients cost US$250,000. The palladium catalyst alone adds $100,000; purifying it out of the product another $30,000.

Finding less-toxic alternatives to the metal could help to reduce environmental harm from palladium waste and move the chemicals industry towards ‘greener’ reactions, says Tianning Diao, an organometallic chemist at New York University. Researchers hope to swap palladium for more common metals, such as iron and nickel, or invent metal-free catalysts that sidestep the issue altogether. Several times in the past two decades, researchers have reported finding palladium-free catalysts. But in what has become a recurring pattern for the field, each heralded discovery turned out to be a mistake.

[…] Part of the challenge of preventing rip-related drownings stems from the lack of a simple method to escape them. Rip currents form when waves pile water near the shoreline. The water then gushes back out to sea, taking the path of least resistance. It might flow along channels carved in between sandbars or next to solid structures, such as jetties or rocky headlands. These types of rips can stick around year after year. Others are more erratic, creating fleeting bursts of seaward-flowing water on smooth, open beaches. People often mislabel rip currents as undertows or rip tides. Rip currents are not caused by tides, however, and undertows are a different, weaker current, formed when water pushed onto the beach moves back offshore along the seabed. Some telltale signs of a rip include a streak of churned-up, sandy water or a dark, flat gap between breaking waves.

It’s not surprising that rip currents are often misunderstood by the public because, for decades, beach-safety experts also had an oversimplified perception of their mechanics. In some of the earliest research on rips in the mid-20th century, American scientists watched sticks, pieces of kelp, and volleyballs float out to sea and described lanes of flowing water extending more than 300 meters offshore. This work formed the basis for the popular view of rip currents as jets flowing perpendicular to the beach, shooting out past the surf. To escape the river of current, experts recommended that bathers swim parallel to the beach — a message once broadcast through education campaigns and warning signs in the United States and Australia. As it turns out, that approach may not always work.

Elsewhere on the continent things are even worse. One study of male high-school leavers in Seoul found 97% were short-sighted. Hong Kong and Singapore are not far behind. And although the problem is worst in East Asia, it is not unique to it. Reliable numbers for America and Europe are harder to come by. But one review article, published in 2015, claimed a European rate of between 20% and 40% — an order of magnitude higher than that which people working in the field think is the “natural,” background rate. For most of those affected, myopia is a lifelong, expensive nuisance. But severe myopia can lead to untreatable vision loss, says Annegret Dahlmann-Noor, a consultant ophthalmologist at Moorfields Eye Hospital, in London. A paper published in 2019 concluded that each one-dioptre worsening in myopia was associated with a 67% increase in prevalence of myopic maculopathy, an untreatable condition that causes blindness. (A dioptre is a measure of a lens’s focusing power.) In some parts of East Asia, 20% of young people have severe myopia, defined as -6 dioptres or worse (see chart 2 in linked story). “This is storing up a big problem for the coming decades,” says Kathryn Rose, head of orthoptics at the University of Technology, Sydney.

In the early spring semester, Lau, also working with Cornell’s Milk Quality Improvement Program, connected with the Cornell Dairy Bar, which sells fluid milk in addition to ice cream on campus. She wanted to assess consumer acceptance for QR code technology that may one day replace the static best-by or sell-by dates commonly found on food products. Customers had a choice: purchasing milk with printed best-by dates, or buying containers with QR codes, which when scanned by a smart phone, would display the best-by date.

In the same Cornell Dairy Bar study, Lau placed a dynamic pricing element where consumers were encouraged to purchase milk with a shorter remaining shelf life — by offering a price discount as the best-by date approached. “During two-month study, over 60% of customers purchased the milk with the QR code, showing a considerable interest in using this new technology,” Lau said. “This revealed that the use of QR codes on food products can be an innovative way to address the larger issue of food waste.” Wiedmann says the technology also exists where smart milk cartons could communicate with smart refrigerators to inform a household of the need for fresh milk.

The study has been published in the Journal of Dairy Science.

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…

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.