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      Beating the heat: These plant-based iridescent films stay cool in the sun

      news.movim.eu / ArsTechnica · Tuesday, 30 May, 2023 - 21:58 · 1 minute

    A colorful, textured bi-layer film made from plant-based materials cools down when it’s in the sun.

    Enlarge / A colorful, textured bi-layer film made from plant-based materials cools down when it’s in the sun. (credit: Qingchen Shen)

    Summer is almost here, bringing higher temperatures and prompting many of us to crank up the air conditioning on particularly hot days. The downside to A/C is that the units gobble up energy and can emit greenhouse gases, contributing further to global warming. Hence, there is strong interest in coming up with eco-friendly alternatives. Scientists from the University of Cambridge have developed an innovative new plant-based film that gets cooler when exposed to sunlight, making it ideal for cooling buildings or cars in the future without needing any external power source. They described their work at a recent meeting of the American Chemical Society.

    The technical term for this approach is passive daytime radiative cooling (PDRC), so named because it doesn't require an injection of energy into the system to disperse heat. The surface emits its own heat into space without being absorbed by the air or atmosphere, thereby becoming several degrees cooler than the surrounding air without needing electrical energy.

    "We know there is spontaneous thermal transfer between objects with different temperatures," Qingchen Shen said at a press conference during the meeting. Their cooling technology exploits that thermal transfer, with a twist. Most PDRC materials (paints, films, and so forth) are white, or have a mirrored finish, to achieve a broadband reflection of sunlight. Pigments or dyes interfere with that since they absorb specific wavelengths of light and only reflect certain colors, thereby transforming energy from the light into heat. The films created by Shen et al . are colored, but it is structural color in the form of nanocrystals, not due to adding pigments or dyes. So color can be added without sacrificing the passive cooling efficiency.

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      Life on Earth might have gotten a boost from the Sun’s mega-tantrums

      news.movim.eu / ArsTechnica · Monday, 22 May, 2023 - 18:55

    Image of eruptions on the surface of the Sun.

    Enlarge (credit: NASA/SDO )

    How, exactly, living things emerged on Earth remains a mystery. Now a new experiment has revealed that blasts of solar particles could have kickstarted the process by creating some of the basic components of life.

    Time in the sun

    Before so much as the first microbe existed, there had to be amino acids thought to have formed in one of the primordial oozes of early Earth. It was previously thought that lightning might have supercharged the formation of amino acids. However, Kensei Kobayashi of Yokohama National University in Japan, along with astrophysicist Vladimir Airapetian of NASA’s Goddard Space Flight Center and a team of researchers from both institutions, have found another possibility: The young Sun’s superflares probably helped give rise to the stuff of life.

    “[Galactic cosmic rays] and [solar energetic particle] events from the young Sun represent the most effective energy sources for the prebiotic formation of biologically important organic compounds,” the researchers said in a study recently published in Life .

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      Researchers craft a fully edible battery

      news.movim.eu / ArsTechnica · Tuesday, 9 May, 2023 - 17:33 · 1 minute

    Image of a gloved hand holding a device, with the ingredients of the device in the background.

    Enlarge (credit: Istituto Italiano di Tecnologia )

    Can you tell me how many batteries you use in a year? A report from the University of Illinois reveals that Americans buy about 3 billion dry-cell batteries annually, which means that an average American ends up using nearly 10 batteries a year. Of course, this shouldn’t come as a surprise given that almost everything we use runs on batteries. What’s shocking is that out of these billions of batteries, about 2,500 end up in the stomachs of kids.

    Almost every day, there are numerous cases of kids swallowing batteries that power their toys, watches, or gadgets; this results in many cases of internal injuries or stomach infections.

    A team of researchers at the Italian Institute of Technology (IIT) in Milan recently created a fully rechargeable battery using nontoxic edible components. This is probably the world’s first battery that is safe to ingest and entirely made of food-grade materials. “Given the level of safety of these batteries, they could be used in children's toys, where there is a high risk of ingestion,” said Mario Caironi, a senior researcher at IIT. However, this isn’t the only solution the edible battery could provide.

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      Elemental music: Interactive periodic table turns He, Fe, Ca into Do, Re, Mi

      news.movim.eu / ArsTechnica · Wednesday, 29 March, 2023 - 15:40 · 1 minute

    A recent college graduate has converted the visible light given off by the elements into audio, creating unique, complex sounds for each one.

    Enlarge / Graduate student W. Walker Smith converted the visible light given off by the elements into audio, creating unique, complex sounds for each one. His personal favorites are helium and zinc. (credit: W. Walker Smith and Alain Barker)

    We're all familiar with the elements of the periodic table, but have you ever wondered what hydrogen or zinc, for example, might sound like? W. Walker Smith, now a graduate student at Indiana University, combined his twin passions of chemistry and music to create what he calls a new audio-visual instrument to communicate the concepts of chemical spectroscopy.

    Smith presented his data sonification project—which essentially transforms the visible spectra of the elements of the periodic table into sound—at a meeting of the American Chemical Society being held this week in Indianapolis, Indiana. Smith even featured audio clips of some of the elements, along with "compositions" featuring larger molecules, during a performance of his "The Sound of Molecules" show.

    As an undergraduate, "I [earned] a dual degree in music composition and chemistry, so I was always looking for a way to turn my chemistry research into music," Smith said during a media briefing . "Eventually, I stumbled across the visible spectra of the elements and I was overwhelmed by how beautiful and different they all look. I thought it would be really cool to turn those visible spectra, those beautiful images, into sound."

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      Human cells hacked to act like squid skin cells could unlock key to camouflage

      news.movim.eu / ArsTechnica · Tuesday, 28 March, 2023 - 17:18 · 1 minute

    Certain squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration.

    Enlarge / Certain squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration. (credit: YouTube/KQED Deep Look )

    Certain cephalopods like cuttlefish, octopuses, and squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration. Scientists would like to learn more about the precise mechanisms underlying this unique ability, but it's not possible to culture squid skin cells in the lab. Researchers at the University of California, Irvine, have discovered a viable solution: replicating the properties of squid skin cells in mammalian (human) cells in the lab. They presented their research at a meeting of the American Chemical Society being held this week in Indianapolis.

    "In general, there's two ways you can achieve transparency," UC Irvine's Alon Gorodetsky, who has been fascinated by squid camouflage for the last decade or so, said during a media briefing at the ACS meeting. "One way is by reducing how much light is absorbed—pigment-based coloration, typically. Another way is by changing how light is scattered, typically by modifying differences in the refractive index." The latter is the focus of his lab's research.

    Squid skin is translucent and features an outer layer of pigment cells called chromatophores that control light absorption. Each chromatophore is attached to muscle fibers that line the skin's surface, and those fibers, in turn, are connected to a nerve fiber. It's a simple matter to stimulate those nerves with electrical pulses, causing the muscles to contract. And because the muscles pull in different directions, the cell expands, along with the pigmented areas, which changes the color. When the cell shrinks, so do the pigmented areas.

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      Tiny “nano-sponges” inspire killer moves in 2023 Dance Your PhD winning video

      news.movim.eu / ArsTechnica · Monday, 20 March, 2023 - 18:26 · 1 minute

    Checkers Marshall’s award-winning dance depicted electrons moving around in crystalline materials that have a variety of applications.

    University of Oregon chemist Checkers Marshall took top honors in the 2023 Dance Your PhD contest, combining hand fans, blue balloons, and original lyrics to make a dance video explaining their work on "nano-sponge" materials for use in carbon capture and drug delivery. Other winning videos provided creative takes on how local trees in the Amazon rainforest produce a protective hormone in response to drought; diffusing ions at the nanoscale, illustrated with a tango; and an artificial intelligence model called PsychGenerator that aims to bring personality and mental health attributes to AI.

    As we've reported previously , the Dance Your PhD contest was established in 2008 by science journalist John Bohannon. It was previously sponsored by Science magazine and the American Association for the Advancement of Science (AAAS) and is now sponsored by AI company Primer, where Bohannon is the director of science. Bohannon told Slate in 2011 that he came up with the idea while trying to figure out how to get a group of stressed-out PhD students in the middle of defending their theses to let off a little steam. So he put together a dance party at Austria's Institute of Molecular Biotechnology , including a contest for whichever candidate could best explain their thesis topics with interpretive dance.

    The contest was such a hit that Bohannon started getting emails asking when the next would be—and Dance Your PhD has continued ever since. It's now in its 15th year. There are four broad categories: physics, chemistry, biology, and social science, with a fairly liberal interpretation of what topics fall under each. Winners were chosen from 28 entries submitted from 12 different countries. All category winners receive $500, while Marshall, as the overall champion, will receive an additional $2,000. And the contest has a new sponsor this year: Sandbox AQ , an Alphabet spinoff focused on tackling large problems by bringing together artificial intelligence and quantum technologies.

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      Kombucha tea inspires new “living material” for biosensing applications

      Jennifer Ouellette · news.movim.eu / ArsTechnica · Friday, 12 February, 2021 - 19:33 · 1 minute

    Brewing kombucha tea. Note the trademark gel-like layer of SCOBY (symbiotic culture of bacteria and yeast).

    Enlarge / Brewing kombucha tea. Note the trademark gel-like layer of SCOBY (symbiotic culture of bacteria and yeast). (credit: Olga Pankova/Getty Images)

    Kombucha tea is all the rage these days as a handy substitute for alcoholic beverages and for its supposed health benefits. The chemistry behind this popular fermented beverage is also inspiring scientists at MIT and Imperial College London to create new kinds of tough "living materials" that could one day be used as biosensors, helping purify water or detect damage to "smart" packing materials, according to a recent paper published in Nature Materials.

    You only need three basic ingredients to make kombucha . Just combine tea and sugar with a kombucha culture known as a SCOBY (symbiotic culture of bacteria and yeast), aka the "mother," also known as a tea mushroom, tea fungus, or a Manchurian mushroom. (It's believed that kombucha tea originated in Manchuria, China, or possibly Russia.) It's basically akin to a sourdough starter. A SCOBY is a firm, gel-like collection of cellulose fiber (biofilm), courtesy of the active bacteria in the culture, creating the perfect breeding ground for the yeast and bacteria to flourish. Dissolve the sugar in non-chlorinated boiling water, then steep some tea leaves of your choice in the hot sugar water before discarding them.

    Once the tea cools, add the SCOBY and pour the whole thing into a sterilized beaker or jar. Then cover the beaker or jar with a paper towel or cheesecloth to keep out insects, let it sit for two to three weeks, and voila! You've got your own home-brewed kombucha. A new "daughter" SCOBY will be floating right at the top of the liquid (technically known in this form as a pellicle). But be forewarned: it's important to avoid contamination during preparation because drinking tainted kombucha can have serious, even fatal, adverse effects . And despite claims that drinking kombucha tea can treat aging, arthritis, cancer, constipation, diabetes, or even AIDS, to date there is no solid scientific evidence to back those claims.

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      Rather than copying Titan, Pluto’s haze may have different origin

      Scott K. Johnson · news.movim.eu / ArsTechnica · Monday, 28 December, 2020 - 16:29 · 1 minute


    Enlarge / Pluto's atmosphere is fairly hazy. (credit: NASA )

    Saturn’s moon Titan is distinctive, in part for its orange-ish and hazy atmosphere. It’s virtually impossible to see surface features because the haze is so opaque in the visible portion of the spectrum; what we know of it comes from things like radar imagery, instead. The haze is the product of chemical reactions in the upper atmosphere, driven by ultraviolet radiation. These then cascade into larger and more complex organic (reminder: that doesn’t mean biological) molecules.

    The New Horizons mission to Pluto showed that the dwarf planet, too, has a haze. It’s less prominent in Pluto’s meager atmosphere, but it is there (it's actually similar to the one on Neptune’s moon Triton ). Because Pluto’s atmosphere isn’t that different from the upper reaches of Titan’s atmosphere, it has been thought that the same chemistry is responsible.

    But a new study led by Panayotis Lavvas at the University of Reims Champagne-Ardenne shows that Pluto’s haze may require a different explanation. On both bodies, the atmosphere contains methane, carbon monoxide, and nitrogen. But if Titan’s process worked at the same rate on Pluto, it wouldn’t make enough haze particles to match what we’ve measured there. As Pluto’s atmosphere is even colder than the upper atmosphere on Titan, that haze particle chemistry should be running slower on Pluto.

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      Don’t try this at home: George’s Marvelous Medicine is quite toxic

      Jennifer Ouellette · news.movim.eu / ArsTechnica · Thursday, 17 December, 2020 - 12:52 · 1 minute

    George's Marvelous Medicine, could be harmful—even fatal—to grandmas, new BMJ study finds.' src='https://cdn.arstechnica.net/wp-content/uploads/2020/12/george2-800x533.jpg' >

    Enlarge / The concoction featured in Road Dahl's 1981 children's book, George's Marvelous Medicine , could be harmful—even fatal—to grandmas, new BMJ study finds. (credit: YouTube/Storyvision Studios UK )

    Famed children's author Roald Dahl greatly admired doctors who pioneered new medicines, and even dedicated his 1981 book, George's Marvelous Medicine —in which a young boy cooks up a potion using various ingredients around his family farm—to "doctors everywhere." Copies of the book contain a disclaimer to readers, warning them not to try to make George's concoction at home, as it could be dangerous. And now a recent paper published in the annual Christmas issue of the British Medical Journal (BMJ) has determined just how toxic the concoction could be if ingested.

    The BMJ's Christmas issue is typically more light-hearted in nature, although the journal maintains that the papers published therein still "adhere to the same high standards of novelty, methodological rigour, reporting transparency, and readability as apply in the regular issue." Past years have included papers on such topics as why 27 is not a dangerous age for musicians, and the side effects of sword swallowing, among others. The most widely read was 1999’s infamous “ Magnetic resonance imaging of male and female genitals during coitus and female sexual arousal .” (We wrote about the paper last year to mark the 20th anniversary of its publication.)

    (Spoilers for the 1981 children's book below.)

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