Picasso‘s favorite pigment may one day recycle metals from your cell phone

A new method helps recover gold from E-waste at a higher rate than it can be extracted from fresh ore.

Enlarge / A new method helps recover gold from E-waste at a higher rate than it can be extracted from fresh ore. (credit: Reiko Matsushita/Shinta Watanabe)

Gold and certain other precious metals are key ingredients in computer chips, including those used in consumer electronics such as smart phones. But it can be difficult to recover and recycle those metals from electronic waste. Japanese researchers have found that a pigment widely used by artists called Prussian blue can extract gold and platinum-group metals from e-waste much more efficiently than conventional bio-based absorbents, according to a recent paper published in the journal Scientific Reports.

“The amount of gold contained in one ton of mobile phones is 300-400 grams, which is much higher by 10-80 times than that in one ton of natural ore,” the authors wrote. “The other elements have a similar situation. Consequently, the recovery of those precious elements from e-wastes is much more effective and efficient when compared to their collections from natural ore.”

Prussian blue is the first modern synthetic pigment. Granted, there was once a pigment known as Egyptian blue used in ancient Egypt for millennia; the Romans called it caeruleum. But after the Roman empire collapsed, the pigment wasn’t used much, and eventually the secret to how it was made was lost. (Scientists have since figured out how to recreate the process.) So before Prussian blue was discovered, painters had to use indigo dye, smalt, or the pricey ultramarine made from lapis lazuli for deep blue hues.

Read 6 remaining paragraphs | Comments

#chemistry, #electronic-waste, #physics, #recycling, #science

X-ray imaging reveals why this 17th century painted yellow rose lost its luster

The pigments used to create the yellow rose in Abraham Mignon's <em>Still Life with Flowers and a Watch</em> have degraded, giving the rose a flatter appearance—the opposite of the 3D illusory effect intended by the artist.

Enlarge / The pigments used to create the yellow rose in Abraham Mignon’s Still Life with Flowers and a Watch have degraded, giving the rose a flatter appearance—the opposite of the 3D illusory effect intended by the artist.

The 17th century still-life painter Abraham Mignon was known for his depictions of flowers, fruit, forests, and grottoes, among other objects. But over time, certain pigments have degraded to such an extent as to alter the artist’s intent. Most notably, a yellow rose prominently featured in Mignon’s Still Life with Flowers and a Watch has become flattened and monochrome, particularly compared to the other blooms featured in the painting.

A team of Dutch and Belgian scientists used chemical and optical imaging techniques to examine the elemental distribution of the various pigments, according to a recent paper published in the journal Science Advances. In this way, they could infer Mignon’s original painting technique—specifically how the artist built up layers to create what would have been a 3D appearance for the original rose.

According to the authors, over time, artist pigments and binders in oil paintings inevitably deteriorate when exposed to external factors such as light, relative humidity, temperature, and/or exposure to solvents, as well as incompatible pigment mixtures. The result was discoloration and color changes that can affect the paint’s structural integrity, causing such defects as loss of transparency, brittleness, or micro-cracks.

Read 10 remaining paragraphs | Comments

#art-conservation, #chemistry, #gaming-culture, #science, #spectroscopy, #x-ray-fluorescence

Mysterious Hypatia stone might hold earliest evidence of Type Ia supernova

Tiny samples of the Hypatia stone next to a small coin. Rare type Ia supernovas are some of the most energetic events in the universe. Researchers found a consistent pattern of 15 elements in the Hypatia stone, unlike anything in our solar system or in the Milky Way

Enlarge / Tiny samples of the Hypatia stone next to a small coin. Rare type Ia supernovas are some of the most energetic events in the universe. Researchers found a consistent pattern of 15 elements in the Hypatia stone, unlike anything in our solar system or in the Milky Way (credit: Jan Kramers)

In 1996, an archaeologist named Aly A. Barakat was doing fieldwork in an Egyptian desert and stumbled across an unusual shiny black pebble now known as the Hypatia stone (after Hypatia of Alexandria). Studies conducted over the last several years indicate that the stone is of extraterrestrial origin. And according to a recent paper published in the journal Icarus, the stone’s parent body was likely born in the aftermath of a rare type Ia supernova explosion.

The  Hypatia stone was found in an area of southwest Egypt known for its Libyan Desert glass, produced by an extreme surface heating event, quite possibly a meteorite. The Hypatia stone may have also come from that impact, although more recent evidence suggests a comet would be a more likely parent body.

The University of Johannesburg’s Jan Kramers and several colleagues have investigated the Hypatia stone for many years. Kramers compared the Hypatia stone’s internal structure to a fruitcake: a poorly mixed dough forming the bulk of the pebble (mixed matrices), with the mineral grains lurking in the stone’s inclusions representing the cherries and nuts. He likened the secondary substances in the stone’s cracks to the flour dusting the gaps in a fruitcake.

Read 11 remaining paragraphs | Comments

#archaeoastronomy, #astronomy, #astrophysics, #chemistry, #forensic-archaeology, #hypatia-stone, #science

Corals convert sunscreen chemical into a toxin that kills them

Image of a coral reef.

Enlarge (credit: Justin Lewis)

Medical authorities have spent years convincing people to use sunscreen to limit their exposure to UV light. But that effort has had a bit of a setback, as several locations have recently banned the use of sunblocks by beachgoers. Those bans took effect after local waters were found to have high levels of some of the chemicals in sunblock, which was associated with the lower health of nearby coral reefs.

Several studies have indicated that one specific sunblock component, a chemical called oxybenzone, is at the root of the problem. But the mechanism by which oxybenzone could harm corals wasn’t clear. And, without that understanding, it’s difficult to tell which sunblocks might pose a risk.

Now, researchers from Stanford University have identified the problem. The corals convert oxybenzone from a chemical that can harmlessly absorb UV light to one that damages biological molecules after being exposed to UV. And there’s evidence that coral bleaching makes matters worse, as the coral is less able to withstand exposure.

Read 10 remaining paragraphs | Comments

#biochemistry, #biology, #chemistry, #corals, #science, #sunscreen

Turning waste into gold drugs

Image of green colored solutions in glass vials.

Enlarge (credit: Krisana Antharith / EyeEm)

Earth Day was April 22, and its usual message—take care of our planet—has been given added urgency by the challenges highlighted in the latest IPCC report. This year, Ars is taking a look at the technologies we normally cover, from cars to chipmaking, and finding out how we can boost their sustainability and minimize their climate impact.

Countless things we use in modern societies, from food to food containers, rely on industrial-scale chemistry. That chemistry often produces materials that aren’t useful to us—and in some cases, they’re hazardous or toxic. Not only are these materials wasteful, but paying to dispose of them safely can add to the costs of materials.

Early developments in green chemistry have mostly focused on finding reaction pathways that limit the production of unwanted byproducts and the use of toxic solvents. But researchers are looking beyond that, trying to find ways to better integrate chemistry into a circular economy, where source materials are either sustainable or recycled.

Read 13 remaining paragraphs | Comments

#chemistry, #green, #green-chemistry, #science, #software, #sustainability

Atomically thin electronics built using chemical reactions

cartoon diagram of a sheet of graphene.

Enlarge (credit: Getty images)

There have been a variety of demonstrations of the capabilities that atomically thin materials can bring to electronics—extremely small size, excellent performance, and some distinctive properties. But almost all of these demonstrations required that the electronics being tested were essentially assembled by hand. Materials like graphene are often placed on a surface at random, and then the wiring needed for it to function is built around that location. It’s not exactly a recipe for mass production.

To the extent there’s been some progress, it’s been limited. One of the more recent efforts involved using graphene and molybdenum disulfide to make the transistor with the smallest gate length. In this case, the two atomically thin materials had to be placed carefully, but not exactly. Any excess material was etched away, and a key feature was made by cutting through the graphene sheet.

This week saw a somewhat different take on constructing these minuscule devices: chemistry. A research team linked up the two materials used in the earlier study, graphene and molybdenum disulfide, using a single bridging molecule that could react with each of them. The chemistry of the bridging molecule also influenced the behavior of a device made using this approach.

Read 12 remaining paragraphs | Comments

#chemistry, #electronics, #graphene, #materials-science, #science

Scientists solve mystery of why these rare spider fossils were preserved

Fossilized spider from the Aix-en-Provence formation in France seen in hand sample overlain with fluorescent microscopy image of the same fossil. UV illumination causes the fossil to glow brightly, revealing more details about its preservation.

Enlarge / Fossilized spider from the Aix-en-Provence formation in France seen in hand sample overlain with fluorescent microscopy image of the same fossil. UV illumination causes the fossil to glow brightly, revealing more details about its preservation. (credit: Olcott et al., 2022)

Scientists have long puzzled over the exceptional preservation of certain fossils of Cenozoic-era biota, including plants, fish, amphibians, spiders, and other insects. The secret: The presence of mats comprised of single-celled microalgae (diatoms) created an anaerobic environment for fossilization and chemically reacted with the spiders’ organic polymers to turn them into thin carbon-rich films. The process is similar to a common industrial treatment to preserve rubber, according to a recent paper published in the journal Communications Earth & Environment.

Most fossils are basically mineralized body parts: shells, bones, and teeth. But softer tissues are far more likely to decay than fossilize, including chitinous exoskeletons, skin, and feathers. Soft-tissue organisms tend to be under-represented among fossils, except for unusual deposits (called Fossil-Lagerstätten) that boast rich arrays of such fossils in remarkable preservation.

“Most life doesn’t become a fossil,” said Alison Olcott, a geologist at the University of Kansas. “It’s hard to become a fossil. You have to die under very specific circumstances, and one of the easiest ways to become a fossil is to have hard parts like bones, horns, and teeth. So, our record of soft-body life and terrestrial life, like spiders, is spotty—but we have these periods of exceptional preservation when all circumstances were harmonious for preservation to happen.”

Read 10 remaining paragraphs | Comments

#aix-en-provence-formation, #chemistry, #diatom, #fluorescent-microscopy, #fossils, #paleontology, #scanning-electron-imaging, #science

New ‘Ionogels’ Are Tough, Stretchable and Easy to Make

They could find use as protective material, 3-D printer “ink” or longer-lasting batteries

— Read more on ScientificAmerican.com

#chemistry, #electronics, #materials-science, #technology

Plant-based nanocrystals could be the secret to preventing crunchy ice cream

Don't you hate it when ice crystals form and make your ice cream all crunchy? Scientists at the University of Tennessee found that plant cellulose could work better than the additives manufacturers currently use to slow the growth of ice crystals.

Enlarge / Don’t you hate it when ice crystals form and make your ice cream all crunchy? Scientists at the University of Tennessee found that plant cellulose could work better than the additives manufacturers currently use to slow the growth of ice crystals. (credit: Sally Anscombe/Getty Images)

We’ve all made the mistake of leaving a container of ice cream on the kitchen counter for a bit too long. Sure, you can refreeze the half-melted treat, but you may find that the texture is far more crunchy than delectably creamy afterward. The culprit is overly large ice crystals. Scientists at the University of Tennessee think they’ve found a plant-based additive to stop the formation of these crystals, and it’s more effective and cheaper than the additives currently used by ice cream manufacturers. The researchers presented their work at this past week’s meeting of the American Chemical Society in San Diego.

“Food science is not cooking,” Tao Wu, a food scientist specializing in carbohydrate chemistry, said during a press conference. “It’s a multi-disciplinary field that uses chemistry, biology, and engineering to solve real-world problems in the production of food. For instance, we must use good chemistry knowledge to produce high-quality ice cream.”

The basic science involved in making ice cream is well known. (Physics students have even been known to use liquid nitrogen to make their own ice cream in the lab.) Just heat milk, cream, and sugar until the sugar dissolves; cool the mixture; and add any flavorings. Then slowly churn that mixture as it freezes. This adds air to the mixture, inflating the volume (overrun). The best ice creams, including gelato, have an overrun of less than 25 percent compared to cheap commercial ice creams, where the overrun can be as high as 100 percent. That higher overrun is why cheap ice creams melt more quickly and don’t store as well. Finally, pack the soft ice cream mixture into containers for the final step in the process (hardening).

Read 9 remaining paragraphs | Comments

#cellulose, #chemistry, #food-science, #ice-cream, #ice-crystals, #science

See Crystals Form a Mesmerizing World of Microscopic Landscapes

A pandemic micrography project

— Read more on ScientificAmerican.com

#basic-chemistry, #chemistry

Shining an infrared light on how “metal soaps” threaten priceless oil paintings

NIST researchers collaborated with the National Gallery of Art and other organizations to study "metal soaps" found in oil paintings. The soaps can cause the painting to degrade over time.

Enlarge / NIST researchers collaborated with the National Gallery of Art and other organizations to study “metal soaps” found in oil paintings. The soaps can cause the painting to degrade over time. (credit: National Gallery of Art/A. Centrone/NIST)

Scientists at the National Institute of Standards and Technology collaborated with the National Gallery of Art and other institutions to study the deterioration of an oil painting, entitled Gypsy Woman with Mandolin (circa 1870), by the 19th-century French landscape and portrait painter Jean-Baptiste-Camille Corot. The researchers used three complementary techniques to analyze paint samples under infrared light to determine the composition of the damaging metal carboxylate soaps that had formed on the top layer of paint, according to a recent paper published in the journal Analytical Chemistry.

“The painting had some problems that art conservators pointed out,” said co-author and NIST researcher Andrea Centrone. “It has 13 layers, many due to restorations that occurred long after the painting was made, and at the very least, the top layer was degrading. They wanted to restore the painting to its original state of appearance and find out what was happening on a microscopic level on the top layer of the painting, and that’s where we started to help.”

Back in 2019, we reported on how many of the oil paintings at the Georgia O’Keeffe Museum in Santa Fe, New Mexico, had been developing tiny, pin-sized blisters, almost like acne, for decades. Conservationists and scholars initially assumed the blemishes were grains of sand trapped in the paint. But then the protrusions grew, spread, and started flaking off, leading to mounting concern. Some paintings have more pronounced protrusions than others, but even when the conservators restored the most damaged canvases, the pimpling (or “art acne”) returned.

Read 11 remaining paragraphs | Comments

#art-and-science, #art-conservation, #chemistry, #gaming-culture, #jean-baptiste-camille-corot, #metal-carboxylates, #national-gallery-of-art, #nist, #physics, #science, #spectroscopy

How Migrating Birds Use Quantum Effects to Navigate

New research hints at the biophysical underpinnings of their ability to use Earth’s magnetic field lines to find their way to their breeding and wintering grounds

— Read more on ScientificAmerican.com

#animals, #biology, #chemistry, #features, #quantum-physics, #spacephysics

Quantum Friction Explains Water’s Freaky Flow

Physicists have finally solved the long-standing mystery of why water moves faster through narrower nanotubes

— Read more on ScientificAmerican.com

#chemistry, #materials-science, #spacephysics

Kombucha cultures make excellent sustainable water filters, study finds

Close-up of fresh SCOBY

Enlarge / Close-up of fresh SCOBY (symbiotic culture of bacteria and yeast) used in kombucha. (credit: Whitepointer/Getty Images)

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.

As we’ve reported previously, 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). The culture is also known as the “mother,” tea mushroom, tea fungus, or Manchurian mushroom. (Kombucha tea is believed to have originated in Manchuria, China, or possibly Russia.)

Whatever you call it, 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 yeast and bacteria. Dissolve the sugar in non-chlorinated boiling water, then steep some tea leaves of your choice in the hot sugar-water before discarding them.

Read 9 remaining paragraphs | Comments

#chemistry, #filtration, #kombucha, #science

Ancient Peruvians partied hard, spiked their beer with hallucinogens to win friends

A vessel from the Wari site of Conchopata features the tree and its tell-tale seed pods sprouting from the head of the Staff God.

Enlarge / A vessel from the Wari site of Conchopata features the tree and its tell-tale seed pods sprouting from the head of the Staff God. (credit: J. Ochatoma Paravicino/M.E. Biwer et al., 2022)

Lacing the beer served at their feasts with hallucinogens may have helped an ancient Peruvian people known as the Wari forge political alliances and expand their empire, according to a new paper published in the journal Antiquity. Recent excavations at a remote Wari outpost called Quilcapampa unearthed seeds from the vilca tree that can be used to produce a potent hallucinogenic drug. The authors think the Wari held one big final blowout before the site was abandoned.

“This is, to my knowledge, the first finding of vilca at a Wari site where we can get a glimpse of its use,” co-author Matthew Biwer, an archaeobotanist at Dickinson College, told Gizmodo. “Vilca seeds or residue has been found in burial tombs before, but we could only assume how it was used. These findings point to a more nuanced understanding of Wari feasting and politics and how vilca was implicated in these practices.”

The Wari empire lasted from around 500 CE to 1100 CE in the central highlands of Peru. There is some debate among scholars as to whether the network of roadways linking various provincial cities constituted a bona fide empire as opposed to a loose economic network. But the Wari’s construction of complex, distinctive architecture and the 2013 discovery of an imperial royal tomb lend credence to the Wari’s empire status. The culture began to decline around 800 CE, largely due to drought. Many central buildings were blocked up, suggesting people thought they might return if the rains did, and there is archaeological evidence of possible warfare and raiding in the empire’s final days as the local infrastructure collapsed and supply chains failed.

Read 13 remaining paragraphs | Comments

#archaeology, #beer, #chemistry, #gaming-culture, #hallucinogens, #history, #science, #wari

How AI Could Prevent the Development of New Illicit Drugs

The DarkNPS algorithm has predicted the formulas of millions of potential drugs

— Read more on ScientificAmerican.com

#artificial-intelligence, #basic-chemistry, #chemistry, #drug-use, #health, #technology

A “war of experts”: revisiting the infamous 19th century Flores Street poisonings

Two recovered and restored portraits of 19th century Portuguese physician Vicente Urbino de Freitas, suspected of poisoning several of his wife's family members in the "Crime of Flores Street"—Portugal's first major forensic case.

Enlarge / Two recovered and restored portraits of 19th century Portuguese physician Vicente Urbino de Freitas, suspected of poisoning several of his wife’s family members in the “Crime of Flores Street”—Portugal’s first major forensic case. (credit: Ricardo Jorge Dinis-Oliveira, 2019)

On January 2, 1890, a Portuguese man named Jose Antonio Sampaio, Jr., died in terrible agony while staying at the Grand Hotel de Paris in Porto, Portugal. The son of a wealthy and highly respected linen merchant, Sampaio Jr. showed signs of poisoning in his final hours, including blood in his vomit. He was attended by his brother-in-law, a physician named Vicente Urbino de Freitas.

Sampaio Jr. was nonetheless buried without incident, and the family might have grieved their loss and moved on. But in late March, Sampaio Jr.’s son and two nieces suddenly became ill after eating almonds with liquor and coconut and chocolate cakes, which had arrived at the Sampaio house on Flores Street via a mysterious package. The children’s uncle, the aforementioned de Freitas, prescribed lemon balm enemas. While the girls recovered, 12-year-old Mario Guilherme Augusto de Sampaio died in spasms and convulsions on April 2.

Once again, the symptoms were consistent with poisoning, and suspicion soon fell on de Freitas. He was arrested, tried, and convicted in 1893, although he maintained his innocence for the rest of his life. This was the infamous “Crime of Flores Street” and it made headlines around the world. The case continues to fascinate Ricardo Jorge Dinis-Oliveira, a forensic toxicologist at the University of Porto, more than 130 years later, because it gave birth to forensic toxicology studies in Portugal and still informs present-day Portuguese medico-legal procedures. It’s also one hell of a story: “It will certainly make a good movie,” Dinis-Oliveira wrote.

Read 22 remaining paragraphs | Comments

#12-days-of-christmas, #chemistry, #flores-street-poisonings, #forensic-toxicology, #forensics, #gaming-culture, #history, #poisoning, #science

Soil Microbe Could Clean Up Nuclear Waste

A bacteria-produced protein could help snag, detect or filter radioactive particles

— Read more on ScientificAmerican.com

#advances, #biochemistry, #chemistry

Robert H. Grubbs, 79, Dies; Chemistry Breakthrough Led to a Nobel

He helped perfect the manufacturing of compounds that are now used to make everything from plastics to pharmaceuticals, marking an advance in “green chemistry.”

#california-institute-of-technology, #chemicals, #chemistry, #deaths-obituaries, #grubbs-robert-h-1942-2021, #kentucky, #nobel-prizes

A sublime landscape: New model explains Pluto’s lumpy plains

Greyscale image of topographic features.

Enlarge / The polygons of Sputnik Planitium. (credit: NASA/JHUAPL/SwRI)

Expectations for active geology on Pluto were pretty low prior to the arrival of the New Horizons probe. But the photos that came back from the dwarf planet revealed a world of mountains, ridges, and… strange lumpy things that don’t have an obvious Earthly analog. One of the more prominent oddities was the plain of Sputnik Planitia, filled with nitrogen ice that was divided into polygonal shapes separated by gullies that were tens of meters deep.

Scientists quickly came up with a partial explanation for these structures: convection, where heat differences cause deeper, warmer nitrogen ices to bubble through the soft material toward the surface. The problem is that the planet has no obvious sources of heat deep inside. Now, however, a group of European researchers is suggesting that the convection could be driven by surface cooling, rather than heat from the planet’s interior. The secret is the sublimation of nitrogen ices directly into vapors.

Lacking heat

Explaining the formations on small, icy bodies like Pluto is difficult because scientists expect that they lack the heat sources that drive plate tectonics, like those on Earth. These icy bodies are small enough that any heat generated by the collisions that built them, and the dwarf planet, dissipated long ago. And they don’t have enough metallic materials for radioisotopes to provide ongoing heat generation. The few exceptions to this, like Europa and Enceladus, are heated by gravitational interactions with the giant planets they orbit, but that’s not an option for Pluto, either.

Read 10 remaining paragraphs | Comments

#chemistry, #geology, #planetary-science, #science

Shirley McBay, Pioneering Mathematician, Is Dead at 86

The first Black student to receive a doctorate from the University of Georgia, she devoted her life to advocating for diversity in science and math education.

#black-people, #chemistry, #colleges-and-universities, #deaths-obituaries, #education-k-12, #equal-educational-opportunities, #massachusetts-institute-of-technology, #mathematics, #mcbay-shirley-1935-2021, #race-and-ethnicity, #spelman-college, #university-of-georgia

Mammoth Tusk Reveals Ancient Mammal’s Travels

Chemical analyses showed an individual mammoth made an epic journey across Alaska

— Read more on ScientificAmerican.com

#basic-chemistry, #chemistry, #graphic-science

See Strands of Ice That Look like Hair Build up on a Dead Tree Branch

This mesmerizing ice formation has befuddled scientists for a century

— Read more on ScientificAmerican.com

#advances, #biochemistry, #chemistry

Secret of tempera’s pleasing properties is how egg yolk interacts with pigment

Renaissance painting of angels and babies.

Enlarge / Detail of Michelangelo’s unfinished painting The Virgin and Child with Saint John and Angels (tempera on wood, ca. 1497), aka The Manchester Madonna. The outlines of two angelic figures on left are rendered in green earth tempera underpaint. (credit: The National Gallery London/Public domain)

Tempera is a painting medium that has been used to decorate everything from early Egyptian sarcophagi to India’s rock-cut temples. The medium was particularly popular with medieval and early Renaissance artists until it was eventually supplanted by oil-based paints. But while there has been a great deal of research on the chemistry of oil paints, tempera has been largely neglected in the scientific literature, according to researchers at the Sorbonne University in France.

To remedy that, the Sorbonne scientists recreated recipes for tempera written down by a medieval Tuscan painter, the better to analyze the flow properties and molecular organization of the paints, according to a recent paper published in the journal Angewandte Chemie. The aim is to gain a more precise understanding of the underlying chemistry in order to aid in ongoing conservation efforts on tempera-based artworks from the Middle Ages in particular.

Tempera in this context refers to a fast-drying paint in which colored pigments are mixed with a water-soluble binder—traditionally egg yolk, often augmented with an agent such as a few drops of vinegar to prevent cracking once the tempera has dried. The powdered pigment and distilled water would be mixed with binder directly onto the palette, or in a bowl. Liquid myrrh was sometimes added to offset the tempera’s rather pungent odor. Artists had to keep adding water as they worked because the medium dried so quickly, and in those days, tempera could not be stored because the yolk would begin to cure, thickening the paint. While tempera fell out of favor after 1500, it is periodically rediscovered. For instance, 20th-century artists like Jacob Lawrence and Andrew Wyeth used tempera in their work.

Read 9 remaining paragraphs | Comments

#art-conservation, #art-history, #chemistry, #gaming-culture, #science, #tempera

Tiny Vibrating Bubbles Could Make Mining More Sustainable

An updated bubbling process allows for more efficient mineral separation

— Read more on ScientificAmerican.com

#advances, #basic-chemistry, #chemistry

The Gene-Synthesis Revolution

Researchers can now design and mass-produce genetic material — a technique that helped build the mRNA vaccines. What could it give us next?

#2021-tech-and-design, #antibiotics, #bacteria, #biology-and-biochemistry, #biotechnology-and-bioengineering, #chemistry, #crispr-dna, #dna-deoxyribonucleic-acid, #genetics-and-heredity, #ginkgo-bioworks-inc, #synthetic-biology

Why Frozen Turkeys Explode When Deep-Fried

When water and boiling oil mix, the result can be volatile

— Read more on ScientificAmerican.com

#basic-chemistry, #chemistry

New iodine-based plasma thruster tested in orbit

Image of a jet of glowing material emerging from a metal box.

Enlarge / A demo version of the new thruster in operation. (credit: ThrustMe)

Most people are probably familiar with iodine through its role as a disinfectant. But if you stayed awake through high school chemistry, then you may have seen a demonstration where powdered iodine was heated. Because its melting and boiling points are very close together at atmospheric pressures, iodine will readily form a purple gas when heated. At lower pressures, it’ll go directly from solid to gas, a process called sublimation.

That, as it turns out, could make it the perfect fuel for a form of highly efficient spacecraft propulsion hardware called ion thrusters. While it has been considered a promising candidate for a while, a commercial company called ThrustMe is now reporting that it has demonstrated an iodine-powered ion thruster in space for the first time.

Ion power

Rockets rely on chemical reactions to expel a large mass of material as quickly as possible, allowing them to generate enough thrust to lift something into space. But that isn’t the most efficient way to generate thrust—we end up trading efficiency in order to get the rapid expulsion needed to overcome gravity. Once in space, that need for speed goes away; we can use more efficient means of expelling material, since a slower rate of acceleration is acceptable for shifting things between different orbits.

Read 13 remaining paragraphs | Comments

#chemistry, #iodine, #ion-thruster, #materials-science, #physics, #rocketry, #science, #spacecraft

What’s Brewing in a Beer Is Startling Complexity

High-powered chemistry lets researchers trace a beer back to its ingredients

— Read more on ScientificAmerican.com

#advances, #basic-chemistry, #chemistry

Researchers demonstrate complete solar-powered hydrocarbon production

Image of mirror and associated hardware.

Enlarge / Either of two reaction chambers (bottom) can be targeted by concentrated sunlight. (credit: ETH Zurich)

Carbon capture. Hydrogen production. Synthetic fuels. All of these technologies have been proposed as potential resources for dealing with the crises created by our carbon dioxide emissions. While they have worked in small pilot demonstrations, most of them haven’t demonstrated that they can scale to provide the economical solutions we need.

In the meantime, a group of European researchers sees the methods as part of a single coherent production platform, one that goes from sunlight and air to kerosene. Thanks to a small installation on the roof of a lab in Zurich, the team has been producing small amounts of different fuels using some mirrors and a handful of reaction chambers. While the full production process would also need to demonstrate that it can scale, the researchers calculate that the platform could fuel the entire commercial aircraft industry using a small fraction of the land in the Sahara.

The process

There are only three steps involved in the process of turning air into fuels. The first is separating out the raw ingredients, specifically carbon dioxide and water. This is done using a small commercial unit from a spinoff of ETH Zurich; the device uses a heating/cooling cycle and amines that absorb both CO2 and H2O at environmental temperatures, releasing them when they are heated. Critically, the supplied water is highly pure and doesn’t compete with the many other uses we have for clean water.

Read 10 remaining paragraphs | Comments

#chemistry, #fuels, #green, #green-chemistry, #science, #solar-power, #sustainability

Hate broccoli and cauliflower? Your microbiome might be partially to blame

Many kids (and adults) don't much like broccoli, cauliflower, brussels sprouts, and other types of cruciferous vegetables. Taste perception is complicated, but per a new study, our unique oral microbiomes might be one reason why.

Enlarge / Many kids (and adults) don’t much like broccoli, cauliflower, brussels sprouts, and other types of cruciferous vegetables. Taste perception is complicated, but per a new study, our unique oral microbiomes might be one reason why. (credit: DNY59/Getty Images)

For many people, nothing is less tantalizing than a big plate of steamed cruciferous vegetables at dinner. Yes, it’s supposed to be good for us, but that bitter taste is just too overpowering and unpleasant. This is especially true for young children, as any frustrated parent can attest. But an aversion to broccoli, cauliflower, and similar foods is not just people being finicky; some genetics are at play. And according to a recent paper in the Journal of Agricultural and Food Chemistry, a person’s oral microbiome may also be an important factor.

In 1931, a chemist named Arthur L. Fox accidentally released the powdered form of phenylthiocarbamide (PTC) in his lab. He didn’t notice anything unusual, but his lab mate sensed a bitter taste. Subsequent experiments confirmed that this variation existed in the broader population and that not being able to taste bitterness was a recessive genetic trait. For instance, about 25 percent of the population can’t taste propylthiouracil (PROP), a chemical that is similar to the bitter compounds found in cabbage, raw broccoli, coffee, tonic water, and dark beers. That population is, like Fox, essentially “taste blind.”

There are 25 “bitterness” genes known thus far; different bitter foods act through different receptors, and people can be high or low responders for one but not another. Many scientists think that those who can sense bitterness are probably responding to compounds called glucosinolates, present in most cruciferous vegetables, like broccoli, Brussels sprouts, and cauliflower. Those glucosinolates are responsible for much of the nutritional benefits of those veggies, but they also break down into pungent compounds that can negatively trigger many people’s bitter taste receptors. (I happen to dislike all three, as well as raw tomatoes, and I refuse to feel bad about that.)

Read 10 remaining paragraphs | Comments

#chemistry, #cruciferous-vegetables, #food-chemistry, #food-science, #human-microbiome, #science, #taste-perception

Searching for solutions to a crisis decades in the making

A worker stands in front of a giant mound of plastic waste.

Enlarge (credit: Makiko Tanigawa / Getty Images)

Island Press is “the nation’s leading publisher on environmental issues.” In its latest release, Thicker than Water, Erica Cirino, a photojournalist and licensed wildlife rehabilitator, explores what becomes of plastic—all 8 billion or so tons of it that humans have manufactured in the last seventy-ish years. 

Plastic’s greatest strength is also its greatest flaw: It takes eons to break down. It breaks apart, into smaller and smaller micro- and nano-sized particles. But unlike natural materials like wood and glass, plastic doesn’t break down into its constituent chemicals. Those micro- and nano-sized particles are still plastic. According to Alice Zhu, a graduate student studying plastics at the University of Toronto, this is because the carbon-carbon bonds that form the backbone of most plastic polymers require an immense amount of energy to break apart. And because these bonds are in synthetic arrangements, there are no microorganisms that can break most of them down (yet).

The big asymmetry

There is a marked disconnect between how long plastic sticks around and how long we get utility from it. Many single-use items, like straws and cutlery, are used for only minutes; thin plastic bags, like those needlessly wrapped around produce and almost everything we order online (and even plastic cutlery), are immediately thrown away. This thin plastic is made of low density polyethylene, which is the most difficult kind to recycle and emits more climate-warming methane and ethylene when exposed to sunlight than other, harder types of plastic. It is also one of the most commonly produced.

Read 10 remaining paragraphs | Comments

#book-review, #chemistry, #plastics, #science

How We Detect Caramel Candy Scent

Pinpointing the receptor responsible for the tasty treat’s aroma underscores the importance of smell

— Read more on ScientificAmerican.com

#biochemistry, #chemistry, #physiology

Scientists recreated classic origin-of-life experiment and made a new discovery

Stanley Miller with the original laboratory equipment used in the 1952 Miller-Urey Experiment, which gave credence to the idea that organic molecules could have been created by the conditions of the early Earth's atmosphere.

Enlarge / Stanley Miller with the original laboratory equipment used in the 1952 Miller-Urey Experiment, which gave credence to the idea that organic molecules could have been created by the conditions of the early Earth’s atmosphere. (credit: Roger Ressmeyer/Corbis/VCG/Getty Images)

In 1952, a University of Chicago chemist named Stanley Miller and his adviser, Harold Urey, conducted a famous experiment. Their results, published the following year, provided the first evidence that the complex organic molecules necessary for the emergence of life (abiogenesis) could be formed using simpler inorganic precursors, essentially founding the field of prebiotic chemistry. Now a team of Spanish and Italian scientists has recreated that seminal experiment and discovered a contributing factor that Miller and Urey missed. According to a new paper published in the journal Scientific Reports, minerals in the borosilicate glass used to make the tubes and flasks for the experiment speed up the rate at which organic molecules form.

In 1924 and 1929, respectively, Alexander Oparin and J.B.S. Haldane had hypothesized that the conditions on our primitive Earth would have favored the kind of chemical reactions that could synthesize complex organic molecules from simple inorganic precursors—sometimes known as the “primordial soup” hypothesis. Amino acids formed first, becoming the building blocks that, when combined, made more complex polymers.

Miller set up an apparatus to test that hypothesis by simulating what scientists at the time believed Earth’s original atmosphere might have been. He sealed methane, ammonia, and hydrogen inside a sterile 5-liter borosilicate glass flask, connected to a second 500-ml flask half-filled with water. Then Miller heated the water, producing vapor, which in turn passed into the larger flask filled with chemicals, creating a mini-primordial atmosphere. There were also continuous electric sparks firing between two electrodes to simulate lighting. Then the “atmosphere” was cooled down, causing the vapor to condense back into water. The water trickled down into a trap at the bottom of the apparatus.

Read 10 remaining paragraphs | Comments

#abiogenesis, #chemistry, #history-of-science, #miller-urey-experiment, #organic-molecules, #origin-of-life, #prebiotic-chemistry, #science

Seminal Michael Faraday paper digitally stored in fluorescent dyes

Harvard researchers have developed a data-storage approach based on mixtures of fluorescent dyes that are printed onto an epoxy surface in tiny spots. The mixture of dyes at each spot encodes information that is then read with a fluorescent microscope.

Optical disks, flash drives, and magnetic hard disk drives can only store digital information for a few decades, and they tend to require a lot of energy to maintain, making these methods less than ideal for long-term data storage. So researchers have been looking into using molecules as alternatives, most notably in DNA data storage. Those methods come with their own challenges, however, including high synthesis costs and slow read and write rates.

Now, Harvard University scientists have figured out how to use fluorescent dyes as bits for a cheaper, faster means of data storage, according to a new paper published in the journal ACS Central Science. The researchers tested their method by storing one of 19th-century physicist Michael Faraday‘s seminal papers on electromagnetism and chemistry, as well as a JPEG image of Faraday.

“This method could provide access to archival data storage at a low cost,” said co-author Amit A. Nagarkar, who conducted the research as a postdoctoral fellow in George Whitesides’ Harvard lab. “[It] provides access to long-term data storage using existing commercial technologies—inkjet printing and fluorescence microscopy.” Nagarkar is now working for a startup company that wants to commercialize the method.

Read 10 remaining paragraphs | Comments

#chemistry, #data-storage, #fluorescent-dyes, #michael-faraday, #science

Self-healing quasicrystals may resurrect hopes of practical applications

X-ray tomography visualization showing two quasicrystals as they start to meld together during cooling. University of Michigan scientists have discovered that quasicrystals exhibit a self-healing phenomenon that could reduce defects.

Enlarge / X-ray tomography visualization showing two quasicrystals as they start to meld together during cooling. University of Michigan scientists have discovered that quasicrystals exhibit a self-healing phenomenon that could reduce defects. (credit: Shahani Group/University of Michigan)

Quasicrystals are a unique class of materials with considerable promise for practical applications because of their unusual properties. But progress toward realizing that commercial potential has been hampered by the fact that the usual manufacturing processes for quasicrystals are prone to producing defects in the form of tiny cracks between crystals known as grain boundaries. A new paper published in the journal Nature Communications found that under certain conditions, quasicrystals can heal themselves—potentially reviving commercial interest in these materials.

The earliest quasicrystals found were metal alloys, usually aluminum with one or more other metals. That has made them useful for a handful of practical applications, such as non-stick coatings for frying pans and anti-corrosive coatings for surgical equipment. But scientists would love to create more complex quasicrystals that are capable, for example, of manipulating light to create new kinds of camouflage or cloaking.

“One reason why industry gave up on quasicrystals is because they’re full of defects,” said co-author Ashwin Shahani, a materials scientist at the University of Michigan. “But we’re hoping to bring quasicrystals back into the mainstream. And this work hints that it can be done.”

Read 11 remaining paragraphs | Comments

#chemistry, #materials-science, #physics, #quasicrystals, #science

This Chemist’s Pandemic Hobby? Firing Medieval Cannonballs.

Gunpowder used in cannons helped change the nature of warfare, but it took a while to get the recipe just right.

#bombs-and-explosives, #chemistry, #middle-ages-historical-period, #omega-journal, #research, #united-states-military-academy, #your-feed-science

Nobel awarded for making common, cheap chemicals into catalysts

Image of a line diagram of a chemical.

Enlarge / Proline is a common amino acid. It’s also an effective catalyst. (credit: Wikimedia Commons )

Platinum is a ferociously expensive metal that is difficult to obtain and purify. Most of the small supply we produce every year isn’t put to use for its properties as a metal. Instead, it’s used as a catalyst for producing a variety of chemicals—and for cleaning up your car’s exhaust. Everything made with platinum carries an added burden of cost and environmental damage because of that use.

This year, the Nobel Prize in Chemistry honors two researchers for helping to trigger a burst of research into catalysts that leave the metals behind. Benjamin List and David MacMillan made key discoveries that started the field of organocatalysis, developing catalysts that could be made from cheap, common chemicals. Their work took a disorganized set of anecdotes and gave it a strong conceptual footing that allowed many other labs to build on their work.

Not so metal

At their heart, chemical reactions involve the transfer of electrons, either between atoms or into new configurations of chemical bonds. Metals are often effective catalysts because they ease the process of transferring electrons. Many metals will easily make a temporary loan of their electrons during a reaction or, if properly prepared, can draw electrons from other chemicals in order to hasten a process.

Read 12 remaining paragraphs | Comments

#catalyst, #chemistry, #nobel-prize, #science

Nobel Prize in Chemistry Awarded for Tool to Build Molecules

Benjamin List and David W.C. MacMillan were honored for work that spurred research into new drugs and reduced the effect of chemistry on the environment.

#chemistry, #nobel-prizes, #research, #science-and-technology, #your-feed-science

New Molecular Tool Kit Wins Chemistry Nobel

Two chemists devised a faster, cleaner and more precise way to construct drug molecules and other modern materials

— Read more on ScientificAmerican.com

#basic-chemistry, #chemistry

The Mystery of Water Drops That Skate Across Oil at Impossible Speeds

The speed of these self-propelling droplets on a hot oil surface seemed to defy physics until researchers broke out the super slow motion camera.

— Read more on ScientificAmerican.com

#chemistry, #materials-science

High-Flying Sensor Detects Living Things from Far Above

A new detector could keep tabs on life on Earth—and maybe beyond

— Read more on ScientificAmerican.com

#advances, #biochemistry, #chemistry

Scientists test medieval gunpowder recipes with 15th-century cannon replica

Researchers tested medieval gunpowder recipes in this replica of an early 15th-century stone-throwing cannon.

Enlarge / Researchers tested medieval gunpowder recipes in this replica of an early 15th-century stone-throwing cannon. (credit: T.S. Ritchie et al., ACS Omega 2021)

Gunpowder—as opposed to modern smokeless powder—isn’t used much these days in current weaponry, although it’s still useful for historical weapons and remains popular for fireworks and other pyrotechnics. An interdisciplinary team of chemists and historians wanted to learn more about how various recipes for gunpowder evolved over the centuries as master gunners tweaked the basic components to achieve better results. The researchers described their findings in a recent paper published in the journal ACS Omega. They even tested a few of the recipes by firing a replica of a 15th-century stone-throwing cannon at a West Point firing range—you know, for science.

Also known as black powder, gunpowder is simple enough, chemically speaking. It’s a mix of sulfur and charcoal (carbon), which serve as fuels, and potassium nitrate (KNO3), an oxidizer also known as saltpeter. First used for warfare around 904 CE in China, its use had spread throughout Europe and Asia by the late 13th century. Modern black powder recipes call for 75 percent saltpeter, 15 percent charcoal, and 10 percent sulfur. But medieval master gunners experimented with many different recipes over the centuries, many of which included additives such as camphor, varnish, or brandy—the purpose of which is still unknown.

By the late 14th century, manufacturers had discovered that one could improve the performance of gunpowder through a wet-grinding process called “corning.” Some kind of liquid (often distilled spirits) would be added as the other ingredients were being ground together, producing a moist paste. The paste would be rolled into balls and then dried, and those balls would be crushed in a mortar by a gunner in the field right before it was used.

Read 10 remaining paragraphs | Comments

#bomb-calorimetry, #chemistry, #combustion, #gunpowder, #medieval-history, #science, #thermodynamics

Immigrants in U.S. Detention Exposed to Hazardous Disinfectants Every Day

The chemical concentrations exceed EPA limits, and new human studies suggest they could do long-term damage

— Read more on ScientificAmerican.com

#chemistry, #health, #toxicology

Study confirms superior sound of a Stradivari is due to the varnish

Violin against a red background.

Enlarge / A 1729 Stradivari known as the “Solomon, Ex-Lambert” on display at Christie’s in New York in March 2007. (credit: Don Emmert/AFP/Getty Images)

Along with Andrea Amati and Andrea Guarneri, Antonio Stradivari dominated the so-called Golden Age of Violins (roughly 1660 to 1750), and the instruments they crafted remain the gold standard today in terms of acoustic quality. World-renowned cellist Yo-Yo Ma has long favored a Stradivarius instrument, as does violinist Joshua Bell. But scientists have been arguing for years about precisely why these instruments have such superior sound. A recent paper published in the journal Angewandte Chemie confirms a theory dating back to 2006: the secret lies in the chemicals used to soak the wood, most notably borax, zinc, copper, alum, and lime water.

I’ve written extensively about this topic in the past. The (perceived) unique sound can’t just be due to the instrument’s geometry, although Stradivari’s geometrical approach did give us the violin’s signature shape. One hypothesis is that Stradivari may have used Alpine spruce that grew during a period of uncommonly cold weather, which caused the annual growth rings to be closer together, making the wood abnormally dense. Another prevailing theory has to do with the varnish: namely, that Stradivari used an ingenious cocktail of honey, egg whites, and gum arabic from sub-Saharan trees—or perhaps salts or other chemicals.

Then again, the difference may be all in our heads. A player’s instrument preference is highly subjective, and there’s some evidence of so-called “psychoacoustics” at play: that is, we’ve become so awed by the name Stradivarius that it influences how we evaluate or respond to the sound of one of Stradivari’s instruments.

Read 14 remaining paragraphs | Comments

#acoustics, #antonio-stradivarius, #chemistry, #gaming-culture, #musical-instruments, #science, #stradivarius-violins

Recreating a medieval mead calls for a giant cauldron to caramelize honey

Screenshot of honey caramelizing in pot

Enlarge / A medieval form of mead called “bochet” calls for caramelizing raw honey in a cauldron over an open flame. (credit: Screenshot/Gemma Tarlach/Gastro Obscura)

Ah, mead, that sweet, honeyed alcoholic beverage that has been a staple at Renaissance Fairs for decades (along with giant turkey legs). It’s also increasingly popular among home craft brewers since it’s relatively easy to make. Those in search of a unique challenge, however, are turning to a special kind of medieval mead called bochet. The only known detailed recipe for bochet dates back to the late 14th century and was lost for centuries, until it was rediscovered around 2009.

Fermentation in general has been around for millennia, and mead (“fermented honey drink”) in particular was brewed throughout ancient Europe, Africa, and Asia. Perhaps the earliest known reference to such a beverage (soma) is found in a sacred Vedic book called the Rigveda, circa 1700-1100 BCE. Mead was the drink of choice in ancient Greece; Danish warriors in the Old English epic poem Beowulf cavort in King Hrothgar’s mead hall; the Welsh bard Taliesin (circa 550 CE) is credited with composing a “Song of Mead”; and mead features heavily in Norse mythology.

There are many different varieties of mead from all over the world. But bochet is a special variety because it calls for caramelized honey; additional spices are optional. This makes it attractive to craft brewers looking for something a little bit different—brewers like Gemma Tarlach, who recently detailed her experiments making bochet in a fascinating article for Atlas Obscura.

Read 11 remaining paragraphs | Comments

#alcoholic-beverages, #chemistry, #fermentation, #gaming-culture, #history, #honey, #mead, #medieval-history, #science

The Science Inside Your Ice Cream

A new video series from Scientific American and Spektrum der Wissenschaft gives you a serving of science.

— Read more on ScientificAmerican.com

#basic-chemistry, #chemistry

A Flexible Fabric Could Harden into a Temporary House or Bridge

Ancient chain mail served as an inspiration for a highly unusual material that might one day lead to such applications

— Read more on ScientificAmerican.com

#chemistry, #materials-science

German chemists identified over 7,700 different chemical formulas in beers

A cold, frosty mug of beer.

Enlarge / German chemists combined two complementary mass spectrometry techniques to analyze 467 different commercial beers from around the world. (credit: Natasha Breen/Getty Images)

People have been brewing beer for millennia, and the basic chemistry of fermentation is well understood. But thanks to advanced analytical techniques, scientists continue to learn more about the many different chemical compounds that contribute to the flavor and aroma of different kinds of beer. The latest such analysis comes courtesy of a team of German scientists who analyzed over 400 commercial beers from 40 countries. The scientists identified at least 7,700 different chemical formulas and tens of thousands of unique molecules, according to a recent paper published in the journal Frontiers in Chemistry. And they did it with a new approach that can analyze a sample in just 10 minutes.

“Beer is an example of enormous chemical complexity,” said co-author Philippe Schmitt-Kopplin of the Technical University of Munich and the Helmholtz Center in Munich. “And thanks to recent improvements in analytical chemistry, comparable in power to the ongoing revolution in the technology of video displays with ever-increasing resolution, we can reveal this complexity in unprecedented detail. Today it’s easy to trace tiny variations in chemistry throughout the food production process, to safeguard quality or to detect hidden adulterations.”

As I’ve written previously, all beer contains hops, a key flavoring agent that also imparts useful antimicrobial properties. To make beer, brewers mash and steep grain in hot water, which converts all that starch into sugars. This is traditionally the stage when hops are added to the liquid extract (wort) and boiled. That turns some of the resins (alpha acids) in the hops into iso-alpha acids, producing beer’s hint of bitterness. Yeast is then added to trigger fermentation, turning the sugars into alcohol. Some craft brewers prefer dry-hopping—hops are added during or after the fermentation stage, after the wort has cooled. They do this as a way to enhance the hoppy flavors without getting excessive bitterness, since there is no isomerization of the alpha acids.

Read 9 remaining paragraphs | Comments

#beer, #chemistry, #food-chemistry, #liquid-chromatography, #mass-spectrometry, #science

Ugly Diamonds Hold a Billion-Plus Years of Earth History

Tiny pockets of fluid inside imperfect diamonds show how Earth changed

— Read more on ScientificAmerican.com

#advances, #chemistry, #geology