Lifeboat Foundation

Oxidation numbers have so far eluded any rigorous quantum mechanical definition. A new SISSA study, published in Nature Physics, provides such a definition based on the theory of topological quantum numbers, which was honored with the 2016 Nobel Prize in Physics, awarded to Thouless, Haldane and Kosterlitz. This result, combined with recent advances in the theory of transport achieved at SISSA, paves the way to an accurate, yet tractable, numerical simulation of a broad class of materials that are important in energy-related technologies and planetary sciences.

Every undergraduate student in the natural sciences learns how to associate an integer oxidation number to a chemical species participating in a reaction. Unfortunately, the very concept of oxidation state has thus far eluded a rigorous quantum mechanical definition, so that no method was known until now to compute oxidation numbers from the fundamental laws of nature, let alone demonstrate that their use in the simulation of charge transport does not spoil the quality of numerical simulations. At the same time, the evaluation of electric currents in ionic conductors, which is required to model their transport properties, is presently based on a cumbersome quantum-mechanical approach that severely limits the feasibility of large-scale computer simulations. Scientists have lately noticed that a simplified model where each atom carries a charge equal to its oxidation number may give results in surprising good agreement with rigorous but much more expensive approaches.

DARPA-funded chemists at the Massachusetts Institute of Technology (MIT) have devised a way to rapidly synthesize and screen millions of novel proteins that could be used as drugs against Ebola and other viruses. The team supports DARPA’s Fold F(x) synthetic chemistry program.

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Researchers at MIT have developed a system for converting the molecular structures of proteins, the basic building blocks of all living beings, into audible sound that resembles musical passages. Then, reversing the process, they can introduce some variations into the music and convert it back into new proteins never before seen in nature. Credit: Zhao Qin and Francisco Martin-Martinez.

Want to create a brand new type of protein that might have useful properties? No problem. Just hum a few bars.

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Organic solid-state lasers are essential for photonic applications, but current-driven lasers are a great challenge to develop in applied physics and materials science. While it is possible to create charge transfer complexes (i.electron-donor-acceptor complexes among two/more molecules or across a large molecule) with p-/n- type organic semiconductors in electrically pumped lasers, the existing difficulties arise from nonradiative loss due to the delocalized states of charge transfer (CT). In a recent report, Kang Wang and a team of researchers in the departments of chemistry, molecular nanostructure and nanotechnology in China demonstrated the enduring action of CT complexes by exciton funneling in p-type organic microcrystals with n-type doping.

They surrounded locally formed CT complexes containing narrow bandgaps with hosts of high levels of energy to behave as artificial light-harvesting systems. They captured the resulting excitation light energy using hosts to deliver to the CT complexes for their function as exciton funnels in order to benefit lasing actions. Wang et al. expect the preliminary results to offer in depth understanding of exciton funneling in light-harvesting systems to develop high-performance organic lasing devices. The new results are now available on Science Advances.

Organic semiconductor lasers that function across the full visible spectrum are of increasing interest due to their practical applications from multiband communication to full-color laser displays. Although they are challenging to attain, electrically pumped organic lasers can advance the existing laser technology to rival organic light-emitting diodes.

Scientists and non-scientists alike have long been dreaming of elements with mighty properties. Perhaps the fictional materials they have conjured up are not as far from reality as it may at first seem.

The periodic table of elements has become one of the defining symbols of chemistry. It is, of course, a handy chart of the building blocks that make up absolutely anything and everything around us, but it is also the outcome of the work of a huge number of scientists, which led to the current understanding of the elements’ atomic structure and behaviour. For those who like organization, patterns and chemistry, what’s not to love?

We synthesise life de-novo in the lab? This is one of the Grand Challenges of contemporary Science. Overall objective of this project is to set important steps in turning chemistry into biology by building fully synthetic chemical systems that contain and integrate some of the essential elements of life: replication, metabolism and compartmentalisation. Functional coupling of any of life’s essential elements has not been achieved, at least not without making use of biomolecules. We now aim to achieve such coupling and develop fully chemical systems to become increasingly life-like. Specific aims are:

To understand our brains, scientists need to know their components. This theme underlies a growing effort in neuroscience to define the different building blocks of the brain—its cells.

With the mouse’s 80 million neurons and our 86 billion, sorting through those delicate, microscopic building blocks is no small feat. A new study from the Allen Institute for Brain Science, which was published today in the journal Nature Neuroscience, describes a large profile of mouse neuron types based on two important characteristics of the cells: their 3D shape and their electrical behavior.

The study, which yielded the largest dataset of its kind from the adult laboratory mouse to date, is part of a larger effort at the Allen Institute to discover the brain’s “periodic table” through large-scale explorations of brain cell types. The researchers hope a better understanding of cell types in a healthy mammalian brain will lay the foundation for uncovering the cell types that underlie human brain disorders and diseases.

The first time Vayu Maini Rekdal manipulated microbes, he made a decent sourdough bread. At the time, young Maini Rekdal, and most people who head to the kitchen to whip up a salad dressing, pop popcorn, ferment vegetables, or caramelize onions, did not consider the crucial chemical reactions behind these concoctions.

Even more crucial are the reactions that happen after the plates are clean. When a slice of sourdough travels through the digestive system, the trillions of microbes that live in our gut help the body break down that bread to absorb the nutrients. Since the human body cannot digest certain substances — all-important fiber, for example — microbes step up to perform chemistry no human can.

“But this kind of microbial metabolism can also be detrimental,” said Maini Rekdal, a graduate student in the lab of Professor Emily Balskus and first-author on their new study published in Science. According to Maini Rekdal, gut microbes can chew up medications, too, often with hazardous side effects. “Maybe the drug is not going to reach its target in the body, maybe it’s going to be toxic all of a sudden, maybe it’s going to be less helpful,” Maini Rekdal said.

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