chemistry (28)

OPVs...

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V. ALTOUNIAN/SCIENCE

Topics: Alternate Energy, Applied Physics, Chemistry, Materials Science, Solar Power

As ultrathin organic solar cells hit new efficiency records, researchers see green energy potential in surprising places.

In November 2021, while the municipal utility in Marburg, Germany, was performing scheduled maintenance on a hot water storage facility, engineers glued 18 solar panels to the outside of the main 10-meter-high cylindrical tank. It’s not the typical home for solar panels, most of which are flat, rigid silicon and glass rectangles arrayed on rooftops or in solar parks. The Marburg facility’s panels, by contrast, are ultrathin organic films made by Heliatek, a German solar company. In the past few years, Heliatek has mounted its flexible panels on the sides of office towers, the curved roofs of bus stops, and even the cylindrical shaft of an 80-meter-tall windmill. The goal: expanding solar power’s reach beyond flat land. “There is a huge market where classical photovoltaics do not work,” says Jan Birnstock, Heliatek’s chief technical officer.

Organic photovoltaics (OPVs) such as Heliatek’s are more than 10 times lighter than silicon panels and in some cases cost just half as much to produce. Some are even transparent, which has architects envisioning solar panels, not just on rooftops, but incorporated into building facades, windows, and even indoor spaces. “We want to change every building into an electricity-generating building,” Birnstock says.

Heliatek’s panels are among the few OPVs in practical use, and they convert about 9% of the energy in sunlight to electricity. But in recent years, researchers around the globe have come up with new materials and designs that, in small, lab-made prototypes, have reached efficiencies of nearly 20%, approaching silicon and alternative inorganic thin-film solar cells, such as those made from a mix of copper, indium, gallium, and selenium (CIGS). Unlike silicon crystals and CIGS, where researchers are mostly limited to the few chemical options nature gives them, OPVs allow them to tweak bonds, rearrange atoms, and mix in elements from across the periodic table. Those changes represent knobs chemists can adjust to improve their materials’ ability to absorb sunlight, conduct charges, and resist degradation. OPVs still fall short of those measures. But, “There is an enormous white space for exploration,” says Stephen Forrest, an OPV chemist at the University of Michigan, Ann Arbor.

Solar Energy Gets Flexible, Robert F. Service, Science Magazine

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The Nobel Prize in Chemistry 2022...

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Topics: Chemistry, Nobel Laureate, Nobel Prize

The Nobel Prize in Chemistry 2022 was awarded jointly to Carolyn R. Bertozzi, Morten Meldal, and K. Barry Sharpless "for the development of click chemistry and bioorthogonal chemistry"

The 2022 Nobel Prize in Chemistry is about making the difficult simple. Barry Sharpless and Morten Meldal have laid the foundations for a functional form of chemistry – click chemistry – where molecular building blocks quickly and efficiently snap into each other. Carolyn Bertozzi has taken click chemistry to a new dimension and brought it into living organisms.

Chemists have long been driven by the desire to be able to build increasingly complicated molecules. In pharmaceutical research, it has often been about being able to artificially recreate natural molecules that have healing properties. This has led to many admirable molecular constructions, which unfortunately are also generally time-consuming and very expensive to produce.

- This year's chemistry prize is about not fussing about it so much and instead starting from the easy and simple. Even if you choose a simple route, you can build advanced and useful molecules, says Johan Åqvist, chairman of the Nobel Committee for Chemistry.

Source: https://www.kva.se/nyheter/nobelpriset-i-kemi-2022/

The Nobel Prize in Chemistry 2022. NobelPrize.org. Nobel Prize Outreach AB 2022. Wed. 5 Oct 2022. < https://www.nobelprize.org/prizes/chemistry/2022/summary/ >

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5 Elements...

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(Credit: concept w/Shutterstock)

Topics: Chemistry, Nobel Laureate, Nobel Prize

Currently, there are 118 elements on the periodic table. If a new element is discovered, naming it involves several factors. Elements can be named after how they were obtained, their attributes, the compound they were isolated from, and places they were discovered. However, they can also be named after the people who found them. Fifteen elements have been named after scientists — here are five of them.

1. Curium (Cm)

2. Fermium (Fm)

3. Meitnerium (Mt)

4. Nobelium (No)

5. Oganesson (Og)

5 Elements Named in Honor of Notable Scientists, Allison Futterman, Discovery Magazine

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WASP-39b and CO2...

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Researchers detected carbon dioxide in WASP-39b’s atmosphere when the exoplanet crossed in front of its star. The data plot shows a telltale blip where infrared wavelengths from the star’s light were absorbed by carbon dioxide on the exoplanet. Credit: NASA, ESA, CSA, Leah Hustak (STScI), Joseph Olmsted (STScI)

Topics: Astrophysics, Chemistry, ESA, Exoplanets, James Webb Space Telescope, NASA

The James Webb Space Telescope — already famous for its mesmerizing images of the cosmos — has done it again. The telescope has captured the first unambiguous evidence of carbon dioxide in the atmosphere of a planet outside the Solar System.

The finding not only provides tantalizing hints about how the exoplanet formed but is also a harbinger for what’s to come as Webb studies more and more alien worlds. It was reported in a manuscript posted on the preprint server arXiv1, ahead of peer review, and is expected to be published in Nature in the coming days. (Nature’s news team is independent of its journals team.)

The discovery is presented in a data plot with none of the luster of Webb’s previous images — which showed galaxies locked in a cosmic dance and radiant clouds in a stellar nursery. But Jessie Christiansen, an astronomer at the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena, describes the data as “gorgeous”.

The plot, or spectrum, reveals detailed information about the atmosphere of the exoplanet WASP-39b, called a hot Jupiter by scientists because it has a diameter similar to Jupiter’s but orbits its star much more closely than Mercury orbits the Sun, making it incredibly hot. The planet, which is more than 200 parsecs from Earth, was initially discovered during ground-based observations2 and later detected by NASA’s Spitzer Space Telescope, which operated between 2003 and 2020. Data from the latter suggested3 that WASP-39b’s atmosphere might contain carbon dioxide, but they were inconclusive.

Webb telescope spots CO2 on exoplanet for first time: what it means for finding alien life, Sharron Hall, Nature

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Perovskite and Maxima...

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The effective mass of the electrons can be derived from the curvature around the maxima of the ARPES measurement data (image, detail). (Courtesy: HZB)

Topics: Alternate Energy, Applied Physics, Battery, Chemistry, Civilization, Climate Change

A longstanding explanation for why perovskite materials make such good solar cells has been cast into doubt thanks to new measurements. Previously, physicists ascribed the favorable optoelectronic properties of lead halide perovskites to the behavior of quasiparticles called polarons within the material’s crystal lattice. Now, however, detailed experiments at Germany’s BESSY II synchrotron revealed that no large polarons are present. The work sheds fresh light on how perovskites can be optimized for real-world applications, including light-emitting diodes, semiconductor lasers, and radiation detectors as well as solar cells.

Lead halide perovskites belong to a family of crystalline materials with an ABXstructure, where A is cesium, methylammonium (MA), or formamidinium (FA); B is lead or tin; and X is chlorine, bromine, or iodine. They are promising candidates for thin-film solar cells and other optoelectronic devices because their tuneable bandgaps enable them to absorb light over a broad range of wavelengths in the solar spectrum. Charge carriers (electrons and holes) also diffuse through them over long distances. These excellent properties give perovskite solar cells a power conversion efficiency of more than 18%, placing them on a par with established solar-cell materials such as silicon, gallium arsenide, and cadmium telluride.

Researchers are still unsure, however, exactly why charge carriers travel so well in perovskites, especially since perovskites contain far more defects than established solar-cell materials. One hypothesis is that polarons – composite particles made up of an electron surrounded by a cloud of ionic phonons, or lattice vibrations – act as screens, preventing charge carriers from interacting with the defects.

Charge-transport mystery deepens in promising solar-cell materials, Isabelle Dumé, Physics World

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Helium and Ukraine...

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Transport dewars like this carry crucial cryogens for scientific instruments.

Topics: Chemistry, Instrumentation, Nuclear Magnetic Resonance, Physics, Research

Scientists who need the gas face tough choices in the face of reduced supply and spiking prices.

Helium supplies, already dicey, got worse this past week when production shut down in Arzew, Algeria. The curtailment joins ongoing disruptions in supplies from Russia and the US Federal Helium Reserve as well as planned maintenance at facilities in Qatar. Helium users in several locations say they are struggling to get the gas they need to keep their scientific instruments running.

“The shortage is scaring most NMR spectroscopists,” says Martha Morton, the director of research instrumentation at the University of Nebraska–Lincoln. Nuclear magnetic resonance instruments and related tools use liquid helium to cool superconducting magnets.

War in Ukraine makes helium shortage more dire, Craig Bettenhausen, Chemical & Engineering News

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Cobalt and Caveats...

Video Source: New York Times

Topics: Battery, Chemistry, Climate Change, Environment, Politics

KASULO, Democratic Republic of Congo — A man in a pinstripe suit with a red pocket square walked around the edge of a giant pit one April afternoon where hundreds of workers often toil in flip-flops, burrowing deep into the ground with shovels and pickaxes.

His polished leather shoes crunched on dust the miners had spilled from nylon bags stuffed with cobalt-laden rocks.

The man, Albert Yuma Mulimbi, is a longtime power broker in the Democratic Republic of Congo and chairman of a government agency that works with international mining companies to tap the nation’s copper and cobalt reserves, used in the fight against global warming.

Mr. Yuma’s professed goal is to turn Congo into a reliable supplier of cobalt, a critical metal in electric vehicles, and shed its anything-goes reputation for tolerating an underworld where children are put to work and unskilled and ill-equipped diggers of all ages get injured or killed.

“We have to reorganize the country and take control of the mining sector,” said Mr. Yuma, who had pulled up to the Kasulo site in a fleet of SUVs carrying a high-level delegation to observe the challenges there.

But to many in Congo and the United States, Mr. Yuma himself is a problem. As chairman of Gécamines, Congo’s state-owned mining enterprise, he has been accused of helping to divert billions of dollars in revenues, according to confidential State Department legal filings reviewed by The New York Times and interviews with a dozen current and former officials in both countries.

Hunt for the ‘Blood Diamond of Batteries’ Impedes Green Energy Push, Dionne Searcey, and Eric Lipton, New York Times

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Lithium and Caveats...

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Image Source: Visual Capitalist

Topics: Alternate Energy, Battery, Biofuels, Chemistry, Climate Change, Environment

California and the Biden administration are pushing incentives to make the United States a global leader in a market that’s beginning to boom: the production of lithium, the lightweight metal needed for the batteries of electric vehicles, and for the storage of renewable energy from power plants.

At the moment nearly all the lithium used in the United States must be imported from China and other nations. But that trend could shift within two years if an efficient method is found to remove lithium from power plant waste in California.

Since the 1970s, California has built power plants that make electricity from geothermal energy—steam from saltwater heated by magma from the molten core of the Earth. It now accounts for 6 percent of California’s power, but it is more expensive to produce than other forms of renewable energy, such as solar and wind power.

But that calculus could change if the wastewater from the process—a whitish, soup-like brine that contains a mixture of dissolved minerals and metals including lithium—can be separated so the lithium could be extracted.

According to a study by the Department of Energy, the Salton Sea in California’s Imperial Valley—one of two large geothermal energy production sites in the state—could produce as much as 600,000 tons of lithium annually.

U.S. Looks to Extract Lithium for Batteries from Geothermal Waste, John Fialka, Scientific American

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Kilonovas and Gold...

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Artist's impression of a neutron-star merger (Courtesy: NASA)

Topics: Astronomy, Astrophysics, Chemistry, Materials Science, Neutron Stars

The amounts of heavy elements such as gold created when black holes merge with neutron stars have been calculated and compared with the amounts expected when pairs of neutron stars merge. The calculations were done by Hsin-Yu Chen and Salvatore Vitale at the Massachusetts Institute of Technology and Francois Foucart at the University of New Hampshire using advanced simulations and gravitational-wave observations made by the LIGO–Virgo collaboration. Their results suggest that merging pairs of neutron stars are likely to be responsible for more heavy elements in the universe than mergers of black holes with neutron stars.

Today, astrophysicists have an incomplete understanding of how elements heavier than iron are made. In this nucleosynthesis process, lighter nuclei must be able to capture neutrons from their surroundings. Astrophysicists believe this can happen in two ways, each producing about half of the heavy elements in the universe. These are the slow process (s-process) that occurs in large stars and the rapid process (r-process), which is believed to occur in extreme conditions such as the explosion of a star in a supernova. However, exactly where the r-process can take place is hotly debated.

One event that could support the r-process is the merger of a pair of neutron stars, which can result in a huge explosion called a kilonova. Indeed, such an event was seen by LIGO–Virgo in 2017, and simultaneous observations using light-based telescopes suggest that heavy elements were created in that event.

Merging neutron stars create more gold than collisions involving black holes, Sam Jarman, Physics World

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Quantum Exorcism...

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Figure 2. Maxwell’s demon is a hypothetical being that can observe individual molecules in a gas-filled box with a partition in the middle separating chambers A and B. If the demon sees a fast-moving gas molecule, it opens a trapdoor in the partition to let fast-moving molecules into chamber B while leaving slow-moving ones behind. Repeating that action would allow the buildup of a temperature difference between the two sides of the partition. A heat engine could use that temperature difference to perform work, which would contradict the second law of thermodynamics.

Topics: Chemistry, History, Materials Science, Quantum Mechanics, Thermodynamics

Thermodynamics is a strange theory. Although it is fundamental to our understanding of the world, it differs dramatically from other physical theories. For that reason, it has been termed the “village witch” of physics.1 Some of the many oddities of thermodynamics are the bizarre philosophical implications of classical statistical mechanics. Well before relativity theory and quantum mechanics brought the paradoxes of modern physics into the public eye, Ludwig Boltzmann, James Clerk Maxwell, and other pioneers of statistical mechanics wrestled with several thought experiments, or demons, that threatened to undermine thermodynamics.

Despite valiant efforts, Maxwell and Boltzmann were unable to completely vanquish the demons besetting the village witch of physics—largely because they were limited to the classical perspective. Today, experimental and theoretical developments in quantum foundations have granted present-day researchers and philosophers greater insights into thermodynamics and statistical mechanics. They allow us to perform a “quantum exorcism” on the demons haunting thermodynamics and banish them once and for all.

Loschmidt’s demon and time reversibility

Boltzmann, a founder of statistical mechanics and thermodynamics, was fascinated by one of the latter field’s seeming paradoxes: How does the irreversible behavior demonstrated by a system reaching thermodynamic equilibrium, such as a cup of coffee cooling down or a gas spreading out, arise from the underlying time-reversible classical mechanics?2 That equilibrating behavior only happens in one direction of time: If you watch a video of a wine glass smashing, you know immediately whether the video was in rewind or not. In contrast, the underlying classical or quantum mechanics are time-reversible: If you were to see a video of lots of billiard balls colliding, you wouldn’t necessarily know whether the video was in rewind or not. Throughout his career, Boltzmann pursued a range of strategies to explain irreversible equilibrating behavior from the underlying reversible dynamics. Boltzmann’s friend Josef Loschmidt famously objected to those attempts. He argued that the underlying classical mechanics allow for the possibility that the momenta are reversed, which would lead to the gas retracing its steps and “anti-equilibrating” to the earlier, lower-entropy state. Boltzmann challenged Loschmidt to try to reverse the momenta, but Loschmidt was unable to do so. Nevertheless, we can envision a demon that could. After all, it is just a matter of practical impossibility—not physical impossibility—that we can’t reach into a box of gas and reverse each molecule’s trajectory.

Technological developments since Loschmidt’s death in 1895 have expanded the horizons of what is practically possible (see figure 1). Although it seemed impossible during his lifetime, Loschmidt’s vision of reversing the momenta was realized by Erwin Hahn in 1950 in the spin-echo experiment, in which atomic spins that have dephased and become disordered are taken back to their earlier state by an RF pulse. If it is practically possible to reverse the momenta, what does that imply about equilibration? Is Loschmidt’s demon triumphant?

The demons haunting thermodynamics, Katie Robertson, Physics Today

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Peat Batteries...

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An aerial view of peat fields in Elva, Estonia. September 30, 2021. REUTERS/Janis Laizans

Topics: Battery, Biofuels, Chemistry, Energy, Green Tech

TARTU, Estonia, Oct 11 (Reuters) - Peat, plentiful in bogs in northern Europe, could be used to make sodium-ion batteries cheaply for use in electric vehicles, scientists at an Estonian university say.

Sodium-ion batteries, which do not contain relatively costly lithium, cobalt, or nickel, are one of the new technologies that battery makers are looking at as they seek alternatives to the dominant lithium-ion model.

Scientists at Estonia's Tartu University say they have found a way to use peat in sodium-ion batteries, which reduces the overall cost, although the technology is still in its infancy.

"Peat is a very cheap raw material - it doesn't cost anything, really," says Enn Lust, head of the Institute of Chemistry at the university.

Energy from bogs: Estonian scientists use peat to make batteries, Janis Laizans and Andrius Sytas, Reuters Science

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Cold Atmospheric Plasmas...

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FIG. 1. Schematic of the motivation and the method for this paper.

Topics: Applied Physics, Chemistry, Physics, Plasma, Research

ABSTRACT

Cold atmospheric plasmas have great application potential due to their production of diverse types of reactive species, so understanding the production mechanism and then improving the production efficiency of the key reactive species are very important. However, plasma chemistry typically comprises a complex network of chemical species and reactions, which greatly hinders the identification of the main production/reduction reactions of the reactive species. Previous studies have identified the main reactions of some plasmas via human experience, but since plasma chemistry is sensitive to discharge conditions, which are much different for different plasmas, widespread application of the experience-dependent method is difficult. In this paper, a method based on graph theory, namely, vital nodes identification, is used for the simplification of plasma chemistry in two ways: (1) holistically identifying the main reactions for all the key reactive species and (2) extracting the main reactions relevant to one key reactive species of interest. This simplification is applied to He + air plasma as a representative, chemically complex plasma, which contains 59 species and 866 chemical reactions, as reported previously. Simplified global models are then developed with the key reactive species and main reactions, and the simulation results are compared with those of the full global model, in which all species and reactions are incorporated. It was found that this simplification reduces the number of reactions by a factor of 8–20 while providing simulation results of the simplified global models, i.e., densities of the key reactive species, which are within a factor of two of the full global model. This finding suggests that the vital nodes identification method can capture the main chemical profile from a chemically complex plasma while greatly reducing the computational load for simulation.

Simplification of plasma chemistry by means of vital nodes identification

Bowen Sun, Dingxin Liu, Yifan Liu, Santu Luo, Mingyan Zhang, Jishen Zhang, Aijun Yang, Xiaohua Wang, and Mingzhe Rong, Journal of Applied Physics

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Interstellar Cellular Membranes...

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Topics: Astrobiology, Biology, Chemistry, Cosmology

The origin of life is one of the great unanswered questions in science. One piece of this puzzle is that life started on Earth 4.5 billion years ago, just a few hundred million years after the formation of the Solar System, and involved numerous critical molecular components. How did all these components come to be available so quickly?

One potential explanation is that the Earth was seeded from space with the building blocks for life. The idea is that space is filled with clouds of gas and dust that contain all the organic molecules necessary for life.

Indeed, astronomers have observed these buildings blocks in interstellar gas clouds. They can see amino acids, the precursors of proteins, and the machinery of life. They can also see the precursors of ribonucleotides, molecules that can store information in the form of DNA.

But there is another crucial component for life – molecules that can form membranes capable of encapsulating and protecting the molecules of life in compartments called protocells. On Earth, the membranes of all cells are made of molecules called phospholipids. But these have never been observed in space. Until now.

First evidence of cell membrane molecules in space, Physics arXiv blog, Astronomy

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Women's History Month, and CRISPR...

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Topics: Biology, Chemistry, DNA, Nobel Prize, Research, Women in Science

This year’s (2020) Nobel Prize in Chemistry has been awarded to two scientists who transformed an obscure bacterial immune mechanism, commonly called CRISPR, into a tool that can simply and cheaply edit the genomes of everything from wheat to mosquitoes to humans. 

The award went jointly to Emmanuelle Charpentier of the Max Planck Unit for the Science of Pathogens and Jennifer Doudna of the University of California, Berkeley, “for the development of a method for genome editing.” They first showed that CRISPR—which stands for clustered regularly interspaced short palindromic repeats—could edit DNA in an in vitro system in a paper published in the 28 June 2012 issue of Science. Their discovery was rapidly expanded on by many others and soon made CRISPR a common tool in labs around the world. The genome editor spawned industries working on making new medicines, agricultural products, and ways to control pests.

Many scientists anticipated that Feng Zhang of the Broad Institute, who showed 6 months later that CRISPR worked in mammalian cells, would share the prize. The institutions of the three scientists are locked in a fierce patent battle over who deserves the intellectual property rights to CRISPR’s discovery, which some estimate could be worth billions of dollars.

“The ability to cut DNA where you want has revolutionized the life sciences. The genetic scissors were discovered 8 years ago, but have already benefited humankind greatly,” Pernilla Wittung Stafshede, a chemical biologist at the Chalmers University of Technology, said at the prize briefing.

CRISPR was also used in one of the most controversial biomedical experiments of the past decade, when a Chinese scientist edited the genomes of human embryos, resulting in the birth of three babies with altered genes. He was widely condemned and eventually sentenced to jail in China, a country that has become a leader in other areas of CRISPR research.

Although scientists were not surprised Doudna and Charpentier won the prize, Charpentier was stunned. “As much as I have been awarded a number of prizes, it’s something you hear, but you don’t completely connect,” she said in a phone call with the Nobel Prize officials. “I was told a number of times that when it happens, you’re very surprised and feel that it’s not real.”

At a press briefing today, Doudna noted she was asleep and missed the initial calls from Sweden, only waking up to answer the phone finally when a Nature reporter called. "She wanted to know if I could comment on the Nobel and I said, Well, who won it? And she was shocked that she was the person to tell me."

CRISPR, the revolutionary genetic ‘scissors,’ honored by Chemistry Nobel, Jon Cohen, Science Magazine, AAAS

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Snapping Polymer Discs...

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Thin polymer discs self-propel by repeated "snapping" motions. Credit: Yongjin Kim, UMass Amherst

Topics: Chemistry, Polymer Science, Materials Science, Research

A polymer-based gel made by researchers in the US and inspired by the Venus flytrap plant can snap, jump and “reset” itself autonomously. The new self-propelled material might have applications in micron-sized robots and other devices that operate without batteries or motors.

“Many plants and animals, especially small ones, use special parts that act like springs and latches to help them move really fast, much faster than animals with muscles alone,” explains team leader Alfred Crosby, a professor of polymer science and engineering in the College of Natural Sciences at UMass Amherst. “The Venus flytraps are good examples of this kind of movement, as are grasshoppers and trap-jaw ants in the animal world.”

Snapping instabilities
The Venus flytrap plant works by regulating the way its turgor pressure – that is, the swelling produced as stored water pushes against a plant cell wall – is distributed through its leaves. Beyond a certain point, this swelling leads to a condition known as snapping instability, where the tiny additional pressure of a fly’s footsteps is enough to cause the plant to snap shut. The plant then automatically regenerates its internal structures in readiness for its next meal.

Polymer gels snap and jump on their own, Isabelle Dumé, Physics World

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Einsteinium Chemistry...

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Topics: Chemistry, Einstein, Materials Science, Research

To date, researchers have created more than two dozen synthetic chemical elements that don’t exist naturally on Earth. Neptunium (atomic number Z = 93) and plutonium (Z = 94), the first two artificial elements after naturally occurring uranium, are produced in nuclear reactors by thousands of kilograms. But the accessibility of transuranic elements drops quickly with Z: Einsteinium (Z = 99) can be made only in microgram quantities in specialized laboratories, fermium (Z = 100) is produced by the picogram and has never been purified, and all elements after that are made just one atom at a time.

There are ways to probe the atomic properties of elements produced atom by atom (see, for example, Physics Today, June 2015, page 14). But when it comes to the traditional way of investigating how atoms behave—mixing them with other substances in solution to form chemical compounds—Es is effectively the end of the periodic table.

Now Rebecca Abergel (head of Lawrence Berkeley National Laboratory’s heavy element chemistry program) and her colleagues have performed the most complicated and informative Es chemistry experiment to date. They chose to react Es with a so-called octadentate ligand—a single organic molecule, held together by the backbone shown in blue, that wraps around a central metal atom and binds to it from all sides—to create the molecular structure shown in the figure. In their previous work, Abergel and colleagues used the same ligand to study transition metals, lanthanides, and lighter actinides. When they were fortunate enough to acquire a few hundred nanograms of Es from Oak Ridge National Laboratory, they used it on that as well.

Einsteinium chemistry captured, Johanna L. Miller, Physics Today

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3D Hydrogel Polymers...

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Fig. 1 Multimaterial 3D printing hydrogel with other polymers. (A) Illustration of the DLP-based multimaterial 3D printing apparatus. (B and C) Processes of printing elastomer and hydrogel structures, respectively. (D) Snapshot of a diagonally symmetric Kelvin form made of AP hydrogel and elastomer. (E) Demonstration of the high deformability of the printed diagonally symmetric Kelvin form. (F) Snapshot of a printed Kelvin foam consisting of rigid polymer, AP hydrogel, and elastomer. (G) Demonstration of the high stretchability of the printed multimaterial Kelvin foam. Scale bar, 5 mm. (Photo credit: Zhe Chen, Zhejiang University.)

Topics: Chemistry, Materials Science, Polymer Science

Abstract
Hydrogel-polymer hybrids have been widely used for various applications such as biomedical devices and flexible electronics. However, the current technologies constrain the geometries of hydrogel-polymer hybrid to laminates consisting of hydrogel with silicone rubbers. This greatly limits the functionality and performance of hydrogel-polymer–based devices and machines. Here, we report a simple yet versatile multimaterial 3D printing approach to fabricate complex hybrid 3D structures consisting of highly stretchable and high–water content acrylamide-PEGDA (AP) hydrogels covalently bonded with diverse UV curable polymers. The hybrid structures are printed on a self-built DLP-based multimaterial 3D printer. We realize covalent bonding between AP hydrogel and other polymers through incomplete polymerization of AP hydrogel initiated by the water-soluble photoinitiator TPO nanoparticles. We demonstrate a few applications taking advantage of this approach. The proposed approach paves a new way to realize multifunctional soft devices and machines by bonding hydrogel with other polymers in 3D forms.

3D printing of highly stretchable hydrogel with diverse UV curable polymers, Science Advances

Qi Ge1,*,†, Zhe Chen2,*, Jianxiang Cheng1, Biao Zhang3,†, Yuan-Fang Zhang4, Honggeng Li4,5, Xiangnan He1, Chao Yuan4, Ji Liu1, Shlomo Magdassi6, and Shaoxing Qu2,†

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COVID, and Math...

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Image Source: Link below

Topics: Biology, Chemistry, COVID-19, Mathematics, Physics

The year 2020 has been defined by the COVID-19 pandemic: The novel coronavirus responsible for it has infected millions of people and caused more than a million deaths. Like HIV, Zika, Ebola, and many influenza strains, the coronavirus made the evolutionary jump from animals to humans before wreaking widespread havoc. The battle to control it continues. When a disease outbreak is identified—usually through an anomalous spike in cases with similar symptoms—scientists rush to understand the new illness. What type of microbe causes the infection? Where did it come from? How does the infection spread? What are its symptoms? What drugs could treat it? In the current epidemic, science has proceeded at a frenetic pace. Virus genomes are quickly sequenced and analyzed, case and death numbers are visualized daily, and hundreds of preprints are shared every day.

Some scientists rush for their microscopes and lab coats to study a new infection; others leap for their calculators and code. A handful of metrics can characterize a new outbreak, guide public health responses, and inform complex models that can forecast the epidemic’s trajectory. Infectious disease epidemiologists, mathematical biologists, biostatisticians, and others with similar expertise try to answer several questions: How quickly is the infection spreading? What fraction of transmission must be blocked to control the spread? How long is someone infectious? How likely are infected people to be hospitalized or die?

Physics is often considered the most mathematical science, but theory and rigorous mathematical analysis also underlie ecology, evolutionary biology, and epidemiology.1 Ideas and people constantly flow between physics and those fields. In fact, the idea of using mathematics to understand infectious disease spread is older than germ theory itself. Daniel Bernoulli of fluid-mechanics fame devised a model to predict the benefit of smallpox inoculations2 in 1760, and Nobel Prize-winning physician Ronald Ross created mathematical models to encourage the use of mosquito control to reduce malaria transmission.3 Some of today’s most prolific infectious disease modelers originally trained as physicists, including Neil Ferguson of Imperial College London, an adviser to the UK government on its COVID-19 response, and Vittoria Colizza of Sorbonne University in Paris, a leader in network modeling of disease spread.

This article introduces the essential mathematical quantities that characterize an outbreak, summarizes how scientists calculate those numbers, and clarify the nuances in interpreting them. For COVID-19, estimates of those quantities are being shared, debated, and updated daily. Physicists are used to distilling real-world complexity into meaningful, parsimonious models, and they can serve as allies in communicating those ideas to the public.

The math behind epidemics, Alison Hill, Physics Today

Alison Hill is an assistant professor in the Institute for Computational Medicine and the infectious disease dynamics group at Johns Hopkins University in Baltimore, Maryland. She is also a visiting scholar at Harvard University in Cambridge, Massachusetts.

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Nobel Prize in Chemistry...

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Topics: Chemistry, Nobel Laureate, Nobel Prize

The Nobel Prize in Chemistry 2020 was awarded jointly to Emmanuelle Charpentier and Jennifer A. Doudna "for the development of a method for genome editing."

The Nobel Prize in Chemistry 2020. NobelPrize.org. Nobel Media AB 2020. Wed. 7 Oct 2020. <https://www.nobelprize.org/prizes/chemistry/2020/summary/>

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Figure

The spike protein of the SARS-CoV-2 virus (gray) is shown with three small antibodies (pink) attached to its receptor binding domains. The spike attaches at the left to the viral membrane (not shown). DIAMOND LIGHT SOURCE

Topics: Chemistry, COVID-19, Physics, Research

As the world anxiously awaits development of one or more vaccines to tame the SARS-CoV-2 virus, other research continues at a feverish pace to find effective treatments for the disease it causes, COVID-19. That work, in which physicists and chemists are deeply involved, has made significant strides in the past several months and has turned up a few surprises. Researchers at the University of Alberta reported at the August virtual meeting of the American Crystallographic Association that a dipeptide-based protease inhibitor used to treat a fatal coronavirus infection in cats also blocks replication of the SARS-CoV-2 virus in samples of monkey lung tissue. Joanne Lemieux, a biochemist at the university, says the antiviral, known as GC373, works by blocking the function of the main protease (Mpro), an enzyme that cleaves the polyproteins translated from viral RNA into individual proteins once it enters human cells.

Lemieux says GC373 has been shown to have no toxic effects in cats. Anivive, a California company that develops pet medicines, has applied for US Food and Drug Administration approval to begin trials in humans. Lemieux’s group crystallized the Mpro in combination with the drug and produced three-dimensional images of how the drug binds strongly to the active pocket on the enzyme. Although GC373 should be effective in its current form, the group is planning further crystallography experiments at the Stanford Synchrotron Radiation Lightsource (SSRL) and the Canadian Light Source to see if a reformulation could optimize it for human use, she says.

Cats and llamas could offer a path to coronavirus therapies, David Kramer, Physics Today

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