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Category: materials – Page 158

Nematodes, a specific sort of microscopic worm, have been proven by Osaka University researchers to be capable of killing cancer cells, according to Interesting Engineering and SciTechDaily.

The study titled “Nematode surface functionalization with hydrogel sheaths tailored in situ” by Wildan Mubarok, Masaki Nakahata, Masaru Kojima and Shinji Sakai showed that Hydrogel-based “sheaths” that can be further modified to transport useful cargo (cancer-killing substances) could be applied to these worms as a coating.

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In 2019, astronomers observed the nearest example to date of a star that was shredded, or “spaghettified,” after approaching too close to a massive black hole.

That tidal disruption of a sun-like star by a black hole 1 million times more massive than itself took place 215 million from Earth. Luckily, this was the first such event bright enough that astronomers from the University of California, Berkeley, could study the optical light from the stellar death, specifically the light’s polarization, to learn more about what happened after the star was torn apart.

Their observations on Oct. 8, 2019, suggest that a lot of the star’s material was blown away at high speed—up to 10,000 kilometers per second—and formed a spherical cloud of gas that blocked most of the high-energy emissions produced as the black hole gobbled up the remainder of the star.

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Waste heat is a promising source of energy conservation and reuse, by means of converting this heat into electricity—a process called thermoelectric conversion. Commercially available thermoelectric conversion devices are synthesized using rare metals. While these are quite efficient, they are expensive, and in the majority of cases, utilize toxic materials. Both these factors have led to these converters being of limited use. One of the alternatives is oxide-based thermoelectric materials, but the primary drawback these suffer from is a lack of evidence of their stability at high temperatures.

A team led by Professor Hiromichi Ohta at the Research Institute for Electronic Science at Hokkaido University has synthesized a barium cobalt oxide thermoelectric converter that is reproducibly stable and efficient at temperatures as high as 600°C. The team’s findings have been published in the journal ACS Applied Materials & Interfaces.

Thermoelectric conversion is driven by the Seebeck effect: When there is a temperature difference across a conducting material, an electric current is generated. However, efficiency of is dependent on a figure called the thermoelectric figure of merit ZT. Historically, oxide-based converters had a low ZT, but recent research has revealed many candidates that have high ZT, but their stability at high temperatures was not well documented.

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The ability to turn superconductivity off and on with a literal flip of a switch in so-called “magic-angle twisted graphene” has allowed engineers at Caltech to observe an unusual phenomenon that may shed new light on superconductivity in general.

The research, led by Stevan Nadj-Perge, assistant professor of applied physics and , was published in the journal Nature on June 15.

Magic-angle twisted graphene, first discovered in 2018, is made from two or three sheets of graphene (a form of carbon consisting of a single layer of atoms in a honeycomb-like lattice pattern) layered atop one another, with each sheet twisted at precisely 1.05 degrees in relation to the one below it. The resulting bilayer or trilayer has unusual electronic properties: for example, it can be made into an insulator or a superconductor depending on how many are added.

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Martin ChartrandListen to the sound, more like a musket than a 3D printed plastic gun.

When it comes to graphene, it appears that superconductivity runs in the family.

Graphene is a single-atom-thin material that can be exfoliated from the same graphite that is found in pencil lead. The ultrathin material is made entirely from carbon atoms that are arranged in a simple hexagonal pattern, similar to that of chicken wire. Since its isolation in 2004, has been found to embody numerous remarkable properties in its single-layer form.

In 2018, MIT researchers found that if two graphene layers are stacked at a very specific “magic” angle, the twisted bilayer structure could exhibit robust superconductivity, a widely sought material state in which an can flow through with zero energy loss. Recently, the same group found a similar superconductive state exists in twisted trilayer graphene—a structure made from three graphene layers stacked at a precise, new magic angle.

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Mars has had its first CT scan, thanks to analyses of seismic waves picked up by NASA’s InSight lander. Diagnosis: The Red Planet’s core is at least partially liquid, as some previous studies had suggested, and is somewhat larger than expected.

InSight reached Mars in late 2018 and soon afterward detected the first known marsquake (SN: 11/26/18; SN: 4/23/19). Since then, the lander’s instruments have picked up more than a thousand temblors, most of them minor rumbles. Many of those quakes originated at a seismically active region more than 1,000 kilometers away from the lander. A small fraction of the quakes had magnitudes ranging from 3.0 to 4.0, and the resulting vibrations have enabled scientists to probe Mars and reveal new clues about its inner structure.

Simon Stähler, a seismologist at ETH Zurich, and colleagues analyzed seismic waves from 11 marsquakes, looking for two types of waves: pressure and shear. Unlike pressure waves, shear waves can’t pass through a liquid, and they move more slowly, traveling side to side through solid materials, rather than in a push-and-pull motion in the same direction a wave is traveling like pressure waves do.

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