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A multitasking nanomachine that can act as a heat engine and a refrigerator at the same time has been created by RIKEN engineers. The device is one of the first to test how quantum effects, which govern the behavior of particles on the smallest scale, might one day be exploited to enhance the performance of nanotechnologies.

Conventional heat engines and refrigerators work by connecting two pools of fluid. Compressing one pool causes its fluid to heat up, while rapidly expanding the other pool cools its fluid. If these operations are done in a periodic cycle, the pools will exchange energy and the system can be used as either a heat engine or a fridge.

It would be impossible to set up a macroscale machine that does both tasks simultaneously—nor would engineers want to, says Keiji Ono of the RIKEN Advanced Device Laboratory. “Combining a traditional heat engine with a refrigerator would make it a completely useless machine,” he says. “It wouldn’t know what to do.”

New research demonstrates a way to use quantum properties of light to transmit information, a key step on the path to the next generation of computing and communications systems.

Researchers at the University of Rochester and Cornell University have taken an important step toward developing a communications network that exchanges information across long distances by using photons, mass-less measures of light that are key elements of quantum computing and quantum communications systems.

The research team has designed a nanoscale node made out of magnetic and semiconducting materials that could interact with other nodes, using laser light to emit and accept photons.

Severe allergy-like reactions in at least eight people who received the COVID-19 vaccine produced by Pfizer and BioNTech (and Moderna now) over the past 2 weeks may be due to a compound in the packaging of the messenger RNA (mRNA) that forms the vaccine’s main ingredient, scientists say. A similar mRNA vaccine developed by Moderna, which was authorized for emergency use in the United States on Friday, also contains the compound, polyethylene glycol (PEG) PEG has never been used before in an approved vaccine, but it is found in many drugs that have occasionally triggered anaphylaxis—a potentially life-threatening reaction that can cause rashes, a plummeting blood pressure, shortness of breath, and a fast heartbeat. Some allergists and immunologists believe a small number of people previously exposed to PEG may have high levels of antibodies against PEG, putting them at risk of an anaphylactic reaction to the vaccine.

Life-threatening responses seen in at least eight people could be linked to polyethylene glycol, known to trigger reactions to some drugs.

Researchers from Tokyo Metropolitan University have discovered a way to make self-assembled nanowires of transition metal chalcogenides at scale using chemical vapor deposition. By changing the substrate where the wires form, they can tune how these wires are arranged, from aligned configurations of atomically thin sheets to random networks of bundles. This paves the way to industrial deployment in next-gen industrial electronics, including energy harvesting, and transparent, efficient, even flexible devices.

Electronics is all about making things smaller—smaller features on a chip, for example, means more computing power in the same amount of space and better efficiency, essential to feeding the increasingly heavy demands of a modern IT infrastructure powered by machine learning and artificial intelligence. And as devices get smaller, the same demands are made of the intricate wiring that ties everything together. The ultimate goal would be a wire that is only an atom or two in thickness. Such nanowires would begin to leverage completely different physics as the electrons that travel through them behave more and more as if they live in a one-dimensional world, not a 3D one.

In fact, scientists already have materials like carbon nanotubes and transition metal chalcogenides (TMCs), mixtures of transition metals and group 16 elements which can self-assemble into atomic-scale nanowires. The trouble is making them long enough, and at scale. A way to mass produce nanowires would be a game changer.

“Once they are ingested, up to 90% of the plastic fragments that reach the intestine are excreted. However, one part is fragmented into nanoplastics which are capable, due to their small size and molecular properties, to penetrate the cells and cause harmful effects. The study establishes that alterations in food absorption have been described, as well as inflammatory reactions in the intestinal walls, changes in the composition and functioning of the gut microbiome, effects on the body’s metabolism and ability to produce, and lastly, alterations in immune responses. The article alerts about the possibility of a long-term exposure to plastic, accumulated throughout generations, could give way to unpredictable changes even in the very genome, as has been observed in some animal models.”

We live in a world invaded by plastic. Its role as a chemically stable, versatile and multi-purpose fostered its massive use, which has finally translated into our current situation of planetary pollution. Moreover, when plastic degrades it breaks into smaller micro and nanoparticles, becoming present in the water we drink, the air we breathe and almost everything we touch. That is how nanoplastics penetrate the organism and produce side effects.

A revised study led by the Universitat Autónoma de Barcelona (UAB), the CREAF and the Centre for Environmental and Marine Studies (CESAM) at the University of Aviero, Portugal, and published in the journal Science Bulletin, verifies that the nanoplastics affect the composition and diversity of our intestinal microbiome and that this can cause damage to our health. This effect can be seen in both vertebrates and invertebrates, and has been proved in situations in which the exposure is widespread and prolonged. Additionally, with alteration of the gut microbiome come alterations in the immune, endocrine and nervous system and therefore, although not enough is known about the specific physiological mechanisms, the study alerts that stress to the gut microbiome could alter the health of humans.

Continue reading “Nanoplastics alter intestinal microbiome and threaten human health” »

On the electromagnetic spectrum, terahertz light is located between infrared radiation and microwaves. It holds enormous potential for tomorrow’s technologies: Among other things, it might succeed 5G by enabling extremely fast mobile communications connections and wireless networks. The bottleneck in the transition from gigahertz to terahertz frequencies has been caused by insufficiently efficient sources and converters. A German-Spanish research team with the participation of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has now developed a material system to generate terahertz pulses much more effectively than before. It is based on graphene, i.e., a super-thin carbon sheet, coated with a metallic lamellar structure. The research group presented its results in the journal ACS Nano.

Some time ago, a team of experts working on the HZDR accelerator ELBE were able to show that graphene can act as a frequency multiplier: When the two-dimensional carbon is irradiated with light pulses in the low terahertz frequency range, these are converted to higher frequencies. Until now, the problem has been that extremely strong input signals, which in turn could only be produced by a full-scale particle accelerator, were required to generate such terahertz pulses efficiently.“This is obviously impractical for future technical applications,” explains the study’s primary author Jan-Christoph Deinert of the Institute of Radiation Physics at HZDR. “So, we looked for a material system that also works with a much less violent input, i.e., with lower field strengths.”

For this purpose, HZDR scientists, together with colleagues from the Catalan Institute of Nanoscience and Nanotechnology (ICN2), the Institute of Photonic Sciences (ICFO), the University of Bielefeld, TU Berlin and the Mainz-based Max Planck Institute for Polymer Research, came up with a new idea: the frequency conversion could be enhanced enormously by coating the graphene with tiny gold lamellae, which possess a fascinating property: “They act like antennas that significantly amplify the incoming terahertz radiation in graphene,” explains project coordinator Klaas-Jan Tielrooij from ICN2. “As a result, we get very strong fields where the graphene is exposed between the lamellae. This allows us to generate terahertz pulses very efficiently.”

Hydrogen is a sustainable source of clean energy that avoids toxic emissions and can add value to multiple sectors in the economy including transportation, power generation, metals manufacturing, among others. Technologies for storing and transporting hydrogen bridge the gap between sustainable energy production and fuel use, and therefore are an essential component of a viable hydrogen economy. But traditional means of storage and transportation are expensive and susceptible to contamination. As a result, researchers are searching for alternative techniques that are reliable, low-cost and simple. More-efficient hydrogen delivery systems would benefit many applications such as stationary power, portable power, and mobile vehicle industries.

Now, as reported in the journal Proceedings of the National Academy of Sciences, researchers have designed and synthesized an effective material for speeding up one of the limiting steps in extracting hydrogen from alcohols. The material, a catalyst, is made from tiny clusters of nickel metal anchored on a 2-D substrate. The team led by researchers at Lawrence Berkeley National Laboratory’s (Berkeley Lab) Molecular Foundry found that the catalyst could cleanly and efficiently accelerate the reaction that removes hydrogen atoms from a liquid chemical carrier. The material is robust and made from earth-abundant metals rather than existing options made from precious metals, and will help make hydrogen a viable energy source for a wide range of applications.

“We present here not merely a catalyst with higher activity than other nickel catalysts that we tested, for an important renewable energy fuel, but also a broader strategy toward using affordable metals in a broad range of reactions,” said Jeff Urban, the Inorganic Nanostructures Facility director at the Molecular Foundry who led the work. The research is part of the Hydrogen Materials Advanced Research Consortium (HyMARC), a consortium funded by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy Hydrogen and Fuel Cell Technologies Office (EERE). Through this effort, five national laboratories work towards the goal to address the scientific gaps blocking the advancement of solid hydrogen storage materials. Outputs from this work will directly feed into EERE’s H2@Scale vision for affordable hydrogen production, storage, distribution and utilization across multiple sectors in the economy.

One step closer to a light into matter molecular synthesizer: 3.

Molecular machine-track conjugate 1 (Figure 1) was designed to use iterative Wittig reactions to form carbon-carbon double bonds between a macrocycle and building blocks abstracted one at a time and in sequence from a track. The Wittig reaction 24, 25, 26 was chosen as it is robust and structurally tolerant, lending itself to exploitation in a range of contexts, including dynamic DNA-template synthesis.⁹ Our machine is based on a rotaxane architecture, in which the macrocycle has a reactive aldehyde attachment and the axle has the building-block sequence encoded as phosphonium salts during its synthesis. The 2, 2-diphenylpropane phosphonium units act both to restrict the position of the ring on the track and, upon deprotonation, as reactive ylide functionalities. Each ylide is large enough to block the passage of the macrocycle, trapping the ring within a compartment defined by the bulky stopper at the terminus of original threading and the next ylide along the track. Once a reactive building block can be reached by the macrocycle-appended aldehyde, it can be removed from the track through a Wittig reaction that adds it to the terminus of the growing chain. Each barrier also contains an aldehyde unit, so that once the building block is added to the end of the chain, it is able to react with the next barrier on the track that the macrocycle can access, enabling the alkene-connected oligomer to grow through successive Wittig reactions.

The specific size and constitution of the 2, 2-diphenylpropane motif of the building blocks proved important for successful machine operation. Early track designs in which the ylide and aldehyde were attached to the same aromatic ring or extended conjugated system proved insufficiently reactive (see Section S7 for a brief discussion of initial designs). Embedding the phosphorus atoms within the vector of the track allowed synthetically accessible triaryl phosphines to be the basis of the track design, expediting the synthesis (see Sections S2 and S3). The phenyl substituent at each phosphorus center (e.g., 4a–4D) also proved important: when a tolyl (4-methylphenyl) linking group was investigated, it proved difficult to develop macrocycles that could both thread during the rotaxane-forming reaction and, subsequently, pass over the phosphine oxide in the track formed from the Wittig reaction.

Continue reading “A Track-Based Molecular Synthesizer that Builds a Single-Sequence Oligomer through Iterative Carbon-Carbon Bond Formation” »

How electrons move together as a group inside cylindrical nanoparticles?

Scientists from the University of Exeter seems to find out the answer to this question. They even have made a breakthrough in the field of electromagnetism, with perspectives for metamaterials research.

In collaboration with the University of Strasbourg, scientists hypothesized how electrons move collectively in tiny metal nanoparticles shaped like cylinders.