Lifeboat Foundation

Nanoparticle superlattice films that form at the solid-liquid interface are important for mesoscale materials but are challenging to analyze on the onset of formation at a solid-liquid interface. In a new report on Science Advances, E. Cepeda-Perez and a research team in materials, physics and chemistry in Germany studied the early stages of nanoparticle assembly at solid-liquid interfaces using liquid-phase electron microscopy. They observed oleylamine-stabilized gold nanoparticles to spontaneously form thin layers on a silicon nitride membrane window of the liquid enclosure. In the first monolayer, the assembly maintained dense packings of hexagonal symmetry independent of the nonpolar solvent type. The second layer displayed geometries ranging from dense packing in a hexagonal honeycomb structure to quasi-crystalline particle arrangements—based on the dielectric constant of the liquid. The complex structures made of weaker interactions remained preserved, while the surface remained immersed in liquid. By fine-tuning the properties of materials involved in nanoparticle superlattice formation, Cepeda-Perez et al. controlled the three-dimensional (3D) geometry of a superlattice, including quasi-crystals (a new state of matter).

Nanoparticles that are densely packed into two or three dimensions can form regular arrays of nanoparticle superlattices. For example, semiconductor particle superlattices can act as “meta” semiconductors when doped with particles to form new mesoscale materials, while plasmonic particles in dense superlattices can couple to form collective modes with angle-dependent and tunable wavelength responses. Large electric fields can occur between such particles for surface-enhanced Raman spectroscopy. Superlattices can be developed at liquid-liquid, gas-liquid and solid-liquid interfaces, where static and dynamic interactions between particle-substrate, particle-particle and particle-liquid interactions can dictate the structure of superlattices. However, it remains difficult to predict such structures in advance. For example, simulating the assembly of superlattices at multiple stages is not yet possible, with very little in-lab real-space data available for modeling.

Meticulously organised fatty acids are responsible for the bacteria-killing, superhydrophobic nanostructures on cicada wings. The team behind the discovery hopes that its work will inspire antimicrobial surfaces that mimic cicada wings for use in settings such as hospitals.

When in contact with dust, pollen and – importantly – water, the cicadas’ superhydrophobic wings repel matter to self-clean. These extraordinary properties are down to fatty acid nanopillars, periodically spaced and of nearly uniform height, that cover the wings.

Past work has generally only described cicadas’ wings as ‘waxy’ and not explained how these fatty acids nanopillars give rise to unique traits. Nor is it known exactly why cicada wings evolved antibacterial nanostructures. These gaps in our knowledge exist, in part, because of how diverse the cicada family is. But Marianne Alleyne’s group at the University of Illinois, Urbana–Champaign, along with colleagues at Sandia National Labs, set out to understand what role chemistry plays in the wings of two evolutionarily divergent species.

Circa 2019 o.o

There are enormous methods such as physical, chemical, and biological, for the synthesis of metallic nanoparticles (MNPs), which has become a matter of focus among material scientists. Green chemistry-based MNP synthesis is an area, which has gained much importance presently due to their non-toxicity and monodispersed nanoparticle preparation methodologies. Among green synthesis methods, plants are considered as efficient candidates for nanoparticle synthesis. The meticulous formation of different sizes and shapes of the nanoparticles using plants has spurred encouraging interest. The rate kinetics and stability of nanoparticle synthesis are well studied as well as appreciated in the arena of materials. Their capability to sequester metal ions and fastidiously define the dimensions using a plethora of capping proteins such as glutathione and phytochelatins is intriguing giving it a monodispersed size. This review is a comprehensive understanding of the metal nanoparticles synthesized by plants and apprehends the mechanism of nanoparticle synthesis exhaustively.

A key epigenetic mark can block the binding of an important gene regulatory protein, and therefore prohibit the gene from being turned off, a new UNSW study in CRISPR-modified mice—published this month in Nature Communications —has shown.

The study has implications for understanding how epigenetics works at a molecular level—and down the track, the scientists hope the research will help them to investigate new treatments for blood disorders.

“Epigenetics looks at how non-permanent, acquired chemical marks on DNA determine whether or not particular genes are expressed,” study leader and UNSW Professor Merlin Crossley says.

A new “all-plant” drink bottle is underway at a Netherlands biochemicals company. These bottles are made from sustainable crops and decompose within a year.

The bottle is made from plant sugars instead of traditional fossil fuels. Avantium is the company behind the bottle. They have already found support from beer company Carlsberg, who plans to sell a plant-plastic lined cardboard bottle in future beverage releases. Coca-Cola and Danone have also backed the product.

Avantium’s chief executive, Tom van Aken told the Guardian that the plan should be finalized by the end of the year, with the bottles hitting supermarket shelves by 2023. “This plastic has very attractive sustainability credentials because it uses no fossil fuels, and can be recycled – but would also degrade in nature much faster than normal plastics do,” says Van Aken.

Circa 2018

E-noses come in a variety of architectures, but most rely exclusively on chemical sensors, such as metal oxides or conducting polymers. The TruffleBot goes a step further: A 3.5-inch-by-2-inch circuit board that sits atop a Raspberry Pi contains eight pairs of sensors in four rows of two. Each sensor pair includes a chemical sensor to detect vapors and a mechanical sensor (a digital barometer) to measure air pressure and temperature.

Then comes the sniffing bit: Odor samples are pushed across these sensors by small air pumps that can be programmed to take up puffs of air in a pattern. “When animals want to smell something, they don’t just passively expose themselves to the chemical. They’re actively sniffing for it—sampling the air and moving around—so the signals that are being received are not static,” says Rosenstein.

Continue reading “Meet the E-Nose That Actually Sniffs” »

A team of researchers from the University of Lille, CNRS, Centrale Lille, University of Artois, in France, and Keele University in the U.K has developed a way to produce ethane from methane using a photochemical looping strategy. In their paper published in the journal Nature Energy, the group describes their process. Fumiaki Amano with the University of Kitakyushu in Japan has published a News & Views piece on the work done by the team in the same journal issue.

Over the past several years, methane has become important for the production of fuels and other chemicals. But due to its stability, converting methane to desired products requires high temperatures and results in less-than-desired selectivity. Developing a way to carry out such conversions without the need for energy intensive heat production has been a goal of chemists in the field for several years. Prior research has suggested that methane coupling is an attractive option due to the ease with which it can be dehydrogenated to ethylene. In this new effort, the researchers followed up on such suggestions, and in so doing, have developed a way to produce ethane from methane that overcomes prior problems.

Amano suggests the success factor used by the researchers centered around the development of a three-part nanocomposite material—by adding phosphotungstic acid and silver cations to a traditional TiO₂ photocatalyst. The resulting Ag–HPW/TiO₂ nanocomposites induced methane coupling which resulted in the production of ethane—and also small amounts of propane and CO₂. The final result was a two-stage looping process that was based on photochemical conversions. Amano notes that the process resulted in silver cation reduction to a metallic, which was followed up by reoxidization of a metallic silver species using oxygen that was irradiated with ultraviolet light. He also points out that the HPW coating that was used on the particles was a major factor in improving selectivity, and suggests that the looping redox cycle is similar in some ways to the reactions that happen in rechargeable batteries.

Magnesium dimer (Mg₂) is a fragile molecule consisting of two weakly interacting atoms held together by the laws of quantum mechanics. It has recently emerged as a potential probe for understanding fundamental phenomena at the intersection of chemistry and ultracold physics, but its use has been thwarted by a half-century-old enigma—five high-lying vibrational states that hold the key to understanding how the magnesium atoms interact but have eluded detection for 50 years.

The lowest fourteen Mg₂ vibrational states were discovered in the 1970s, but both early and recent experiments should have observed a total of nineteen states. Like a quantum cold case, experimental efforts to find the last five failed, and Mg₂ was almost forgotten. Until now.

Piotr Piecuch, Michigan State University Distinguished Professor and MSU Foundation Professor of chemistry, along with College of Natural Science Department of Chemistry graduate students Stephen H. Yuwono and Ilias Magoulas, developed new, computationally derived evidence that not only made a quantum leap in first-principles quantum chemistry, but finally solved the 50-year-old Mg₂ mystery.

Molecular dynamics is at the point of simulating bulk matter – but don’t expect it to predict the future.

The TV series Devs took as its premise the idea that a quantum computer of sufficient power could simulate the world so completely that it could project events accurately back into the distant past (the Crucifixion or prehistory) and predict the future. At face value somewhat absurd, the scenario supplied a framework on which to hang questions about determinism and free will (and less happily, the Many Worlds interpretation of quantum mechanics).

Quite what quantum computers will do for molecular simulations remains to be seen, but the excitement about them shouldn’t eclipse the staggering advances still being made in classical simulation. Full ab initio quantum-chemical calculations are very computationally expensive even with the inevitable approximations they entail, so it has been challenging to bring this degree of precision to traditional molecular dynamics, where molecular interactions are still typically described by classical potentials. Even simulating pure water, where accurate modelling of hydrogen bonding and the ionic disassociation of molecules involves quantum effects, has been tough.