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Category: chemistry – Page 306

Researchers at Osaka University synthesized twisted molecular wires just one molecule thick that can conduct electricity with less resistance compared with previous devices. This work may lead to carbon-based electronic devices that require fewer toxic materials or harsh processing methods.

Organic conductors, which are carbon-based materials that can conduct electricity, are an exciting new technology. Compared with conventional silicon electronics, can be synthesized more easily, and can even be made into molecular wires. However, these structures suffer from reduced , which prevents them from being used in consumer devices. Now, a team of researchers from The Institute of Scientific and Industrial Research and the Graduate School of Engineering Science at Osaka University has developed a new kind of made from oligothiophene with periodic twists that can carry electric current with less resistance.

Molecular wires are composed by several-nanometer-scale long molecules that have alternating single and double chemical bonds. Orbitals, which are states that electrons can occupy around an atom or molecule, can be localized or extended in space. In this case, the pi orbitals from overlap to form large “islands” that electrons can hop between. Because electrons can hop most efficiently between levels that are close in energy, fluctuations in the can create energy barriers. “The mobility of charges, and thus the overall conductivity of the molecular , can be improved if the charge mobility can be improved by suppressing such fluctuations,” first author Yutaka Ie says.

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A team of researchers affiliated with several institutions in Germany has developed new chemistry for improved control of the volume of liquid in volumetric additive manufacturing. In their paper published in the journal Nature, the group describes their process and how well it worked when tested.

Three-dimensional has made many headlines over the past decade as it has revolutionized the for a wide variety of products. Most 3D printing involves controlling gantries that work together to position a nozzle that applies different types of material to a base to build products. More recently, some new types of 3D printers have been developed for volumetric additive manufacturing, or VAM, that use light to induce polymerization in a liquid to create products. They work by building products a layer at a time. In this new effort, the researchers have improved the way that polymerization starts in VAM applications. By adding the ability to control the volume of liquid precursor involved in the initiation process, they were able to increase the resolution of VAM printing by 10 times. They call their newly improved process xolography because it involves the use of two crossing light beams to solidify a desired object.

The process begins with creating a rectangular sheet of light using a laser fired into a tub of liquid precursor. The laser excites the precursor molecules inside of the rectangle, preparing them for the second beam of light. The second laser is then directed into the rectangle as a preformed image slice. When the slice is projected into the rectangle, the excited precursor molecules solidify into a polymer, forming a solidified slice. The resin volume is then moved (the sheet remains fixed in place) so that the process can be repeated to create another slice. The overall process is repeated, creating more slices as it goes, until the desired shape is achieved.

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German scientists are researching a method to produce hydrogen using light and photoactive compounds on an organic chemical basis.

Hydrogen is considered to be one of the alternative energy sources of the future. So far, however, the costly and energy-intensive production process has been a major problem with regard to the environmental friendliness of this substance, which is in itself CO2 neutral. For this reason, increasing numbers of scientists around the world are researching other methods of producing hydrogen: from algae, for example. (IO reported). Scientists in Germany at the Friedrich Schiller University, the Leibniz Institute for Photonic Technologies (Leibniz IPHT) and the University of Ulm have taken inspiration from nature for their method of producing hydrogen.

To do so, the team from the “CataLight” Collaborative Research Center at the Universities of Jena and Ulm has combined new organic dyes with non-precious metal catalyst molecules that release gaseous hydrogen in water when irradiated with light. This substitute has shown a remarkable impact in terms of longevity and effect after excitation by visible light, they write in their study, published in Chemistry – A European Journal.

Photosynthesis as inspiration

In nature, sunlight is most effectively stored in chemical bonds through photosynthesis, because the light-collecting and reactive complexes in the thylakoid membrane are fixed in chloroplasts. The researchers led by Prof. Felix Schacher have achieved this type of arrangement with the help of polymers that interact with both hydrophilic and hydrophobic substances. These charged, so-called graft copolymers are produced artificially.

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Scientists at Lehigh University are developing a tiny generating plant, housed on a silicon chip, that they believe can produce enough hydrogen to run power-consuming portable devices.

The amount of hydrogen produced was small, but it was enough to demonstrate that the Lehigh project is feasible. Given time the Lehigh group believes they will develop a working generating plant, housed on a silicon chip that produces sufficient quantities of hydrogen to run different types of power consuming portable devices.

‘About 10 years ago people starting thinking: ‘can we take the same fabrication methods for silicon chips and instead of using them for electronics, use them for something else? said Mayuresh Kothare, assistant professor of chemical engineering.

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A team of researchers affiliated with several institutions in the U.K. and one in Saudi Arabia has developed a way to produce jet fuel using carbon dioxide as a main ingredient. In their paper published in the journal Nature Communications, the group describes their process and its efficiency.

As scientists continue to look for ways to reduce the amount of emitted into the atmosphere, they have increasingly focused on certain business sectors. One of those sectors is the , which accounts for approximately 12% of transportation-related carbon dioxide emissions. Curbing in the aviation industry has proved to be challenging due to the difficulty of fitting heavy batteries inside of aircraft. In this new effort, the researchers have developed a that can be used to produce carbon-neutral jet fuel.

The researchers used a process called the organic combustion method to convert carbon dioxide in the air into jet fuel and other products. It involved using an iron catalyst (with added potassium and manganese) along with hydrogen, citric acid and carbon dioxide heated to 350 degrees C. The process forced the apart from the oxygen atoms in CO2 molecules, which then bonded with hydrogen atoms, producing the kind of hydrocarbon molecules that comprise liquid jet fuel. The process also resulted in the creation of water molecules and other products.

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Scientists in Australia have developed a process for calculating the perfect size and density of quantum dots needed to achieve record efficiency in solar panels.

Quantum dots, man-made nanocrystals 100, 000 times thinner than a sheet of paper, can be used as sensitisers, absorbing infrared and and transferring it to other molecules.

This could enable new types of to capture more of the light spectrum and generate more electrical current, through a process of ‘light fusion’ known as photochemical upconversion.

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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 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.

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Summary: Artificial intelligence technology redesigned a bacterial protein that helps researchers track serotonin in the brain in real-time.

Source: NIH

Serotonin is a neurochemical that plays a critical role in the way the brain controls our thoughts and feelings. For example, many antidepressants are designed to alter serotonin signals sent between neurons.

In an article in Cell, National Institutes of Health-funded researchers described how they used advanced genetic engineering techniques to transform a bacterial protein into a new research tool that may help monitor serotonin transmission with greater fidelity than current methods. Preclinical experiments, primarily in mice, showed that the sensor could detect subtle, real-time changes in brain serotonin levels during sleep, fear, and social interactions, as well as test the effectiveness of new psychoactive drugs.

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“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 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.

The health effects of being exposed to nanoplastics was traditionally evaluated in aquatic animals such as molluscs, crustaceans and fish. Recent in vitro analyzes, using cell cultures of fish and mammals, has allowed scientists to analyze the changes in gene expression associated with the presence of nanoplastics from a toxicological viewpoint. The majority of neurological, endocrine and immunological tracts in these vertebrates are very similar to those of humans, and therefore authors warn that some of the effects observed in these models could also be applied to humans. Understanding and analyzing the process through which these plastic fragments penetrate the organism and harm it is fundamental, as is determining precisely the amount and typology of nanoplastics polluting the environment.

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