Lifeboat Foundation

Astrophysicists at the University of Jena (Germany) prove that dust particles in space are mixed with ice.

The matter between the stars in a galaxy – called the interstellar medium – consists not only of gas, but also of a great deal of dust. At some point in time, stars and planets originated in such an environment, because the dust particles can clump together and merge into celestial bodies. Important chemical processes also take place on these particles, from which complex organic – possibly even prebiotic – molecules emerge. However, for these processes to be possible, there has to be water. In particularly cold cosmic environments, water occurs in the form of ice. Until now, however, the connection between ice and dust in these regions of space was unclear. A research team from Friedrich Schiller University Jena and the Max Planck Institute for Astronomy has now proven that the dust particles and the ice are mixed. They report their findings in the current issue of the research journal Nature Astronomy.

Better modelling of physico-chemical processes in space.

Physicists at Chalmers, together with colleagues in Russia and Poland, have managed to achieve ultrastrong coupling between light and matter at room temperature. The discovery is of importance for fundamental research and might pave the way for advances within, for example, light sources, nanomachinery, and quantum technology.

A set of two coupled oscillators is one of the most fundamental and abundant systems in physics. It is a very general toy model that describes a plethora of systems ranging from guitar strings, acoustic resonators, and the physics of children’s swings, to molecules and chemical reactions, from gravitationally bound systems to quantum cavity electrodynamics. The degree of coupling between the two oscillators is an important parameter that mostly determines the behavior of the coupled system. However, the question is rarely asked about the upper limit by which two pendula can couple to each other – and what consequences such coupling can have.

The newly presented results, published in Nature Communications, offer a glimpse into the domain of the so-called ultrastrong coupling, wherein the coupling strength becomes comparable to the resonant frequency of the oscillators. The coupling in this work is realized through interaction between light and electrons in a tiny system consisting of two gold mirrors separated by a small distance and plasmonic gold nanorods. On a surface that is a hundred times smaller than the end of a human hair, the researchers have shown that it is possible to create controllable ultrastrong interaction between light and matter at ambient conditions – that is, at room temperature and atmospheric pressure.

Lil bits of info on DNA methylation, clocks.

Breakthrough advances in medicine and better nutrition have dramatically improved the longevity of the average human over the past two centuries. But that’s not to say that some couldn’t go on to live a long life even before the advent of modern medicine. As long as they were spared by disease, wars, and other risks that can bring an untimely death, humans could live to see their 70s, 80s, and even reach 100 years old as far back as ancient Rome.

The longevity of humans is somewhat exceptional among primates. Chimpanzees, our closest living relatives, rarely make it past age 50, despite them sharing over 99% of our DNA. In a new study, researchers think they’ve found our secret: chemical changes along our genome that occurred around 7–8 million years ago when our ancestors branched away from the lineage of chimps.

Continue reading “Humans live much longer than chimps due to a slower epigenetic ‘clock’” »

Particle accelerators generate high-energy beams of electrons, protons and ions for a wide range of applications, including particle colliders that shed light on nature’s subatomic components, X-ray lasers that film atoms and molecules during chemical reactions and medical devices for treating cancer.

As a rule of thumb, the longer the accelerator, the more powerful it is. Now, a team led by scientists at the Department of Energy’s SLAC National Accelerator Laboratory has invented a new type of accelerator structure that delivers a 10 times larger energy gain over a given distance than conventional ones. This could make accelerators used for a given application 10 times shorter.

The key idea behind the technology, described in a recent article in Applied Physics Letters, is to use terahertz radiation to boost particle energies.

Physicists at Chalmers University of Technology in Sweden, together with colleagues in Russia and Poland, have managed to achieve ultra-strong coupling between light and matter at room temperature. The discovery is of importance for fundamental research and might pave the way for advances in light sources, nanomachinery and quantum technology.

A set of two coupled oscillators is one of the most fundamental and widely used systems in physics. It is a very general toy model that describes a plethora of systems including guitar strings, acoustic resonators, the physics of children’s swings, molecules and chemical reactions, gravitationally bound systems, and quantum cavity electrodynamics.

The degree of coupling between the two oscillators is an important parameter that mostly determines the behavior of the coupled system. However, not much is known about the upper limit by which two pendula can couple to each other—and what consequences such coupling can have.

Researchers have created a molecule in a single, precisely characterized quantum state by merging two carefully prepared atoms.

Researchers have demonstrated a quantum molecular assembler—a device that takes individual atoms as inputs and merges them into a molecule in a desired quantum state. The team used lasers to trap and cool one sodium (Na) atom and one cesium (Cs) atom, bring them together, and merge them into an NaCs molecule in a specific quantum state. Such a quantum-controlled molecule is a promising building block for quantum computers and could help researchers study the quantum details of chemical reactions.

Circa 2008

Cytokinesis partitions the cell by a cleavage furrow in animals but by a new cross wall in plants. How this new wall assembles at the molecular level and connects with the mother cell wall remains unclear. A lethal Arabidopsis embryogenesis mutant designated root-, shoot-, hypocotyl-defective (rsh) provides some clues: RSH encodes extensin AtEXT3, a structural glycoprotein located in the nascent cross wall or “cell plate” and also in mature cell walls. Here we report that electron micrographs of rsh mutant cells lacking RSH extensin correspond to a wall phenotype typified by incomplete cross wall assembly. Biochemical characterization of the purified RSH glycoprotein isolated from wild-type Arabidopsis cell cultures confirmed its identity as AtEXT3: a (hydroxy)proline-rich glyco protein comprising 11 identical amphiphilic peptide repeats with a 28-residue periodicity: SOOOOKKHYVYKSOOOOVKHYSOOOVYH (O = Hyp), each repeat containing a hydrophobic isodityrosine cross-link motif (YVY, underlined). Atomic force microscopy of RSH glycoprotein imaged its propensity for self-assembly into a dendritic scaffold. Extensin peroxidase catalyzed in vitro formation of insoluble RSH gels with concomitant tyrosine cross-linking, hence this likelihood in muro. We conclude that self-assembling amphiphiles of lysine-rich RSH extensin form positively charged scaffolds in the cell plate. These react with negatively charged pectin to create an extensin pectate coacervate that may template further orderly deposition of the new cross wall at cytokinesis.

Conflict of interest statement

Continue reading “Self-assembly of the plant cell wall requires an extensin scaffold” »

Eindhoven University of Technology researchers found five different phases in mixtures of two substances.

Frozen water can take on up to three forms at the same time when it melts: liquid, ice, and gas. This principle, which states that many substances can occur in up to three phases simultaneously, was explained 150 years ago by the Gibbs phase rule. Today, researchers from Eindhoven University of Technology and University Paris-Saclay are defying this classical theory, with proof of a five-phase equilibrium, something that many scholars considered impossible. This new knowledge yields useful insights for industries that work with complex mixtures, such as in the production of mayonnaise, paint, or LCD’s. The researchers have published their results in the journal Physical Review Letters.

The founder of contemporary thermodynamics and physical chemistry is the American physicist Josiah Willard Gibbs. In the 1870s he derived the phase rule, which describes the maximum number of different phases a substance or mixture of substances can assume simultaneously. For pure substances, the Gibbs Phase Rule predicts a maximum of 3 phases.

CIEQSFTTLFACQTAAEIWRAFGYTVKIMVDNGNCRLHVC: these forty letters are a set of instructions for building a sophisticated medical device designed to recognize the flu virus in your body. The device latches onto the virus and deactivates the part of it that breaks into your cells. It is impossibly tiny—smaller than the virus on which it operates—and it can be manufactured, in tremendous quantities, by your own cells. It’s a protein.

Proteins—molecular machines capable of building, transforming, and interacting with other molecules—do most of the work of life. Antibodies, which defend our cells against invaders, are proteins. So are hormones, which deliver messages within us; enzymes, which carry out the chemical reactions we need to generate energy; and the myosin in our muscles, which contract when we move. A protein is a large molecule built from smaller molecules called amino acids. Our bodies use twenty amino acids to create proteins; our cells chain them together, following instructions in our DNA. (Each letter in a protein’s formula represents an amino acid: the first two in the flu-targeting protein above are cysteine and isoleucine.) After they’re assembled, these long chains crumple up into what often look like random globs. But the seeming chaos in their collapse is actually highly choreographed. Identical strings of amino acids almost always “fold” into identical three-dimensional shapes. This reliability allows each cell to create, on demand, its own suite of purpose-built biological tools. “Proteins are the most sophisticated molecules in the known universe,” Neil King, a biochemist at the University of Washington’s Institute for Protein Design (I.P.D.), told me. In their efficiency, refinement, and subtlety, they surpass pretty much anything that human beings can build.

Today, biochemists engineer proteins to fight infections, produce biofuels, and improve food stability. Usually, they tweak formulas that nature has already discovered, often by evolving new versions of naturally occurring proteins in their labs. But “de novo” protein design—design from scratch—has been “the holy grail of protein science for many decades,” Sarel Fleishman, a biochemist at the Weizmann Institute of Science, in Israel, told me. Designer proteins could help us cure diseases; build new kinds of materials and electronics; clean up the environment; create and transform life itself. In 2018, Frances Arnold, a chemical engineer at the California Institute of Technology, shared the Nobel Prize in Chemistry for her work on protein design. In April, when the coronavirus pandemic was peaking on the coasts, we spoke over video chat. Arnold, framed by palm trees, sat outside her home, in sunny Southern California. I asked how she thought about the potential of protein design. “Well, I think you just have to look at the world behind me, right?” she said. “Nature, for billions of years, has figured out how to extract resources from the environment—sunlight, carbon dioxide—and convert those into remarkable, living, functioning machines. That’s what we want to do—and do it sustainably, right? Do it in a way that life can go on.”