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Category: nanotechnology – Page 146

Mimicking the human body, specifically the actuators that control muscle movement, is of immense interest around the globe. In recent years, it has led to many innovations to improve robotics, prosthetic limbs and more, but creating these actuators typically involves complex processes, with expensive and hard-to-find materials.

Researchers at The University of Texas at Austin and Penn State University have created a new type of fiber that can perform like a muscle actuator, in many ways better than other options that exist today. And, most importantly, these muscle-like fibers are simple to make and recycle.

In a new paper published in Nature Nanotechnology (“Nanostructured block copolymer muscles”), the researchers showed that these fibers, which they initially discovered while working on another project, are more efficient, flexible and able to handle increased strain compared to what’s out there today. These fibers could be used in a variety of ways, including medicine and robotics.

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Our cells perform a marvel of engineering when it comes to packing information into small spaces. Every time a cell divides, it bundles up an amazing 4 meters of DNA into 46 tiny packages, each of which is only several millionths of a meter in length. Researchers from EMBL Heidelberg and the Julius-Maximilians-Universität Würzburg have now discovered how a family of DNA motor proteins succeeds in packaging loosely arranged strands of DNA into compact individual chromosomes during cell division.

The researchers studied , a critical to the process of chromosome formation. Although this complex was discovered more than three decades ago, its mode of action remained largely unexplored. In 2018, researchers from the Häring group at EMBL Heidelberg and their collaborators showed that condensin molecules create loops of DNA, which may explain how chromosomes are formed. However, the inner workings by which the complex achieves this feat remained unknown.

“We have been working on this problem for a long time. But only now, by combining different experimental approaches, we have found an answer to this long-standing question,” said Christian Häring, former Group Leader at EMBL Heidelberg and now Professor at the Julius-Maximilians-Universität Würzburg.

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A new technology is using particles of gold to make colors. With further work, the method developed at Aalto University could herald a new display technology.

The technique uses nanocylinders suspended in a gel. The gel only transmits certain colors when lit by polarized light, and the color depends on the orientation of the gold nanocylinders. In a clever twist, a collaboration led by Anton Kuzyk’s and Juho Pokki’s research groups used DNA molecules to control the orientation of gold nanocylinders in the gel.

“DNA isn’t just an information carrier—it can also be a building block. We designed the DNA molecules to have a certain melting temperature, so we could basically program the material,” says Aalto doctoral candidate Joonas Ryssy, the study’s lead author. When the gel heats past the , the DNA molecules loosen their grip and the gold nanocylinders change orientation. When the temperature drops, they tighten up again, and the nanoparticles go back to their original position.

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Nanosheets are finely structured two-dimensional materials and have great potential for innovation. They are fixed on top of each other in layered crystals, and must first be separated from each other so that they can be used, for example, to filter gas mixtures or for efficient gas barriers. A research team at the University of Bayreuth has now developed a gentle, environmentally-friendly process for this difficult process of delamination that can even be used on an industrial scale. This is the first time that a crystal from the technologically attractive group of zeolites has been made usable for a broad field of potential applications.

The delamination process developed in Bayreuth under the direction of Prof. Dr. Josef Breu is characterized by the fact that the structures of the isolated from each other remain undamaged. It also has the advantage that it can be used at normal room temperature. The researchers present their results in detail in Science Advances.

The two-dimensional nanosheets, which lie on top of each other in layered crystals, are held together by electrostatic forces. In order for them to be used for technological applications, the electrostatic forces must be overcome, and the nanosheets detached from each other. A method particularly suitable for this is osmotic swelling, in which the nanosheets are forced apart by water and the molecules and ions dissolved in it. So far, however, it has only been possible to apply it to a few types of crystals, including some clay minerals, titanates, and niobates. For the group of , however, whose nanosheets are highly interesting for the production of functional membranes due to their silicate-containing fine structures, the mechanism of osmotic swelling has not yet been applicable.

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It’s a hot topic, at least on social media: tiny plastic particles allegedly end up not only in oceans and lakes, but also in drinking water—and, yes, even in bottled mineral water. Eawag and the Zurich Water Works launched a joint project in 2019 to find out whether the tiniest of particles, measuring less than a thousandth of a millimeter across, actually find their way from lake water into drinking water pipes and therefore into homes, hospitals and restaurants.

The results are now in, and they include some reassuring findings. In a report published today in the Journal of Hazardous Materials, the researchers show that even if untreated water contained considerable quantities of nanoplastics, these particles were retained in sand filters very efficiently during water treatment. Both in and in a larger test facility located directly on the premises of the Zurich Water Works, the biologically active slow sand filter was the most effective at retaining nanoparticles—achieving an efficacy level in the region of 99.9%.

So far, there has only been limited research into how exactly nanoplastics are formed. “But it would appear that the degradation of larger plastic particles in the environment eventually results in nanoplastics,” says Ralf Kägi, Head of Eawag’s Particle Laboratory. However, even the process of identifying nanoplastic particles is anything but easy. For this, the team of researchers from Eawag, ETH Zurich, EPFL and the Politecnico di Torino used labeled nanoplastic particles, whose route through—or final location in—the water treatment process could be tracked using a mass spectrometer. This process is similar to that used in medicine, where are specifically labeled in order to monitor their potential distribution in the human body.

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Once the tiny, iron-based particles are added to the water, the lithium is drawn out of the water and binds to them. Then with the help of a magnet, the nanoparticles can be collected in just minutes with the lithium hitching a ride, no longer suspended in the liquid and ready for easy extraction. After the lithium is extracted, the recharged nanoparticles can be used again.

New approach uses magnetic nanoparticles to extract valuable rare earth elements from geothermal fluids.

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On-surface synthesis made the fabrication of extended, atomically precise π-conjugated nanostructures on solid supports possible, with graphene nanoribbons (GNRs) and porphyrin-derived oligomers standing out. To date, examples combining these two prominent material classes are scarce, even though the chemically versatile porphyrins and the atomistic details of the nanographene spacers promise an easy tunability of structural and functional properties of the resulting hybrid structures. Here, we report the on-surface synthesis of extended benzenoid-and nonbenzenoid-coupled porphyrin–graphene nanoribbon hybrids by sequential Ullmann-type and cyclodehydrogenation reactions of a tailored Zn(II) 5,15-bis(5-bromo-1-naphthyl)porphyrin (Por(BrNaph)2) precursor on Au(111) and Ag(111).

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