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Category: nanotechnology – Page 106

High-performance, realistic computer simulations are crucially important for science and engineering, even allowing scientists to predict how individual molecules will behave.

Watch the Q&A here: https://youtu.be/aRGH5lC0pLc.
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Scientists have always used models. Since the ancient Ptolemaic model of the universe through to renaissance astrolabes, models have mapped out the consequences of predictions. They allow scientists to explore indirectly worlds which they could never access.

Join Sir Richard Catlow as he explores how high-performance computer simulations have transformed the way scientists comprehend our world. From testing hypotheses at planetary scale to developing a personalised approach for the fight against Covid.

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X-ray diffraction has been used for more than a hundred years to understand the structure of crystals or proteins—for instance, in 1952 the well-known double helix structure of the DNA that carries genetic information was discovered in this way. In this technique, the object under investigation is bombarded with short-wavelength X-ray beams. The diffracted beams then interfere and thus create characteristic diffraction patterns from which one can gain information about the shape of the object.

For several years now it has been possible to study even single nanoparticles in this way, using very short and extremely intense X-ray pulses. However, this typically only yields a two-dimensional image of the particle. A team of researchers led by ETH professor Daniela Rupp, together with colleagues at the universities of Rostock and Freiburg, the TU Berlin and DESY in Hamburg, have now found a way to also calculate the three-dimensional structure from a single , so that one can “look” at the particle from all directions. In the future it should even be possible to make 3D-movies of the dynamics of nanostructures in this way. The results of this research have recently been published in the scientific journal Science Advances.

Daniela Rupp has been assistant professor at ETH Zurich since 2019, where she leads the research group “Nanostructures and ultra-fast X-ray science.” Together with her team she tries to better understand the interaction between very intense X-ray pulses and matter. As a model system they use nanoparticles, which they also investigate at the Paul Scherrer Institute. “For the future there are great opportunities at the new Maloja instrument, on which we were the first user group to make measurements at the beginning of last year. Right now our team there is activating the attosecond mode, with which we can even observe the dynamics of electrons,” says Rupp.

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This is a clip from Technocalyps, a documentary in three parts about the exponential growth of technology and trans-humanism, made by Hans Moravec. The documentary came out in 1998, and then a new version was made in 2006. This is how the film-makers themselves describe what the movie is about:

“The accelerating advances in genetics, brain research, artificial intelligence, bionics and nanotechnology seem to converge to one goal: to overcome human limits and create higher forms of intelligent life and to create transhuman life.”

You can see the whole documentary here: https://www.youtube.com/watch?v=fKvyXBPXSbk. Or, if you’re more righteous then I am, you can order the DVD on technocalyps.com.

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Graphene is a strange material. Understanding its properties is both a fundamental question of science and a promising avenue for new technologies. A team of researchers from the Institute of Science and Technology Austria (ISTA) and the Weizmann Institute of Science has studied what happens when they layer four sheets of it on top of each other and how this can lead to new forms of exotic superconductivity.

Imagine a sheet of material just one layer of atoms thick—less than a millionth of a millimeter. While this may sound fantastical, such a material exists: it is called graphene.

Graphene is an allotrope of carbon in the form of a single layer of atoms in a two-dimensional hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes of carbon, including graphite, charcoal, carbon nanotubes, and fullerenes. In proportion to its thickness, it is about 100 times stronger than the strongest steel.

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Studying the relationship between the arrangement of water molecules incorporated into layered materials like clays and the arrangement of ions within these materials has been a difficult experiment to conduct.

However, researchers have now succeeded in observing these interactions for the first time by utilizing a technique commonly used for measuring extremely small masses and molecular interactions at the nanoscale.

The nanoscale refers to a length scale that is extremely small, typically on the order of nanometers (nm), which is one billionth of a meter. At this scale, materials and systems exhibit unique properties and behaviors that are different from those observed at larger length scales. The prefix “nano-” is derived from the Greek word “nanos,” which means “dwarf” or “very small.” Nanoscale phenomena are relevant to many fields, including materials science, chemistry, biology, and physics.

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Similar in function to ballast tanks in submarines or fish bladders, many water-based bacteria use gas vesicles to regulate their floatability. In a new publication in Cell, scientists from the Departments of Bionanoscience and Imaging Physics now describe the molecular structure of these vesicles for the first time. These gas vesicles were also recently repurposed as contrast agents for ultrasound imaging.

Gas vesicles (GVs) are hollow, cylindrical nanostructures made of a thin protein-based shell and filled with gas. Similar in function to ballast tanks in submarines or fish bladders, many water-based bacteria use these structures to regulate their floatability. “For example, certain cyanobacteria use gas vesicles to float to the surface in order to harvest light for photosynthesis, a phenomenon sometimes seen at enormous scale in toxic algal blooms,” says Arjen Jakobi, Assistant Professor at the Department of Bionanoscience.

There are very specific requirements for such structures: for bacteria to stay afloat, GVs must occupy a substantial proportion of the cell, which involves forming compartments that extend over hundreds of nanometers in size. To maximize floatability, the shell must be constructed from minimal material. At the same time, the shell needs to provide resistance to the pressure from the surrounding water to maintain the ability to float with changes in water depth. GVs have therefore evolved as rigid, thin-walled structures composed of a single protein that repeats many thousands of times to form the GV shell.

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Glass nanoparticles trapped by lasers in extreme vacuum are considered a promising platform for exploring the limits of the quantum world. Since the advent of quantum theory, the question at which sizes an object starts being described by the laws of quantum physics rather than the rules of classical physics has remained unanswered.

A team formed by Lukas Novotny (ETH Zurich), Markus Aspelmeyer (University of Vienna), Oriol Romero-Isart (University of Innsbruck), and Romain Quidant (Zurich) is attempting to answer precisely this question within the ERC-Synergy project Q-Xtreme. A crucial step on the way to this goal is to reduce the energy stored in the motion of the nanoparticle as much as possible, i.e. to cool the particle down to the so-called quantum ground-state.

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Lipid nanoparticles (LNPs) transport small molecules into the body. The most well-known LNP cargo is mRNA, the key constituent of some of the early vaccines against COVID-19. But that is just one application: LNPs can carry many different types of payload, and have applications beyond vaccines.

Barbara Mui has been working on LNPs (and their predecessors, liposomes) since she was a PhD student in Pieter Cullis’s group in the 1990s. “In those days, LNPs encapsulated anti-cancer drugs,” says Mui, who is currently a senior scientist at Acuitas, the company that developed the LNPs used in the Pfizer-BioNTech mRNA vaccine against SARS-CoV-2. She says it soon became clear that LNPs worked even better as carriers of polynucleotides. “The first one that worked really well was encapsulating small RNAs,” Mui recalls.

But it was mRNA where LNPs proved most effective, primarily because LNPs are comprised of positively charged lipid nanoparticles that encapsulate negatively charged mRNA. Once in the body, LNPs enter cells via endocytosis into endosomes and are released into the cytoplasm. “Without the specially designed chemistry, the LNP and mRNA would be degraded in the endosome,” says Kathryn Whitehead, professor in the departments of chemical engineering and biomedical engineering at Carnegie Mellon University.

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Experts consider glass nanoparticles kept inside extreme vacuum layers as potential platforms for examining the quantum world’s limits. However, a question in the field of quantum theory remains unanswered: at which size does an object start being described by quantum physics laws rather than classical physics laws?

Achieving Quantum-State Cooling in More Than One Direction Is Challenging

SciTechDaily reports that a research team attempted to precisely answer the question through the ERC-Synergy project Q-Xtreme. The team comprised Lukas Novotny from ETH Zurich, Markus Aspelmeyer from the University of Vienna, Oriol Romero-Isart from the University of Innsbruck, and Romain Quidant from Zurich.

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The soot produced by unburnt hydrocarbon flames is the second largest contributor to global warming, while also harming human health. Researchers have developed state-of-the-art, high-speed imaging techniques to study turbulent flames, yet they are limited to an imaging rate of million-frames-per-second. Physicists are therefore keen to obtain a complete picture of flame-laser interactions via single-pulse imaging.

In a new report published in Light: Science & Applications, Yogeshwar Nath Mishra and a research team at the Caltech Optical Imaging Laboratory, the NASA Jet propulsion lab, department of physics, and the Institute of Engineering Thermodynamics in the U.S., and Germany, used single-shot laser-sheet comprised ultrafast photography per billion frames per second, for the first time, to observe the dynamics of laser-flames.

The team noted laser-induced incandescence, elastic light scattering and the fluorescence of soot precursors such as polycyclic aromatic hydrocarbons in , with a single nanosecond laser pulse. The research outcomes provide strong experimental evidence to support soot inception and growth mechanisms in flames. Mishra and the team combined a variety of techniques to probe the short-lived species in turbulent environments to unravel the mysteries of hot plasma, nuclear fusion and sonoluminescence.

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