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Category: chemistry – Page 412

Progress Towards Using Quantum Computers for Solving Quantum Chemistry and Machine Learning

IonQ used its trapped-ion computer and a scalable co-design framework for solving chemistry problems. They applied it to compute the ground-state energy of the water molecule. The robust operation of the trapped ion quantum computer yields energy estimates with errors approaching the chemical accuracy, which is the target threshold necessary for predicting the rates of chemical reaction dynamics.

Quantum chemistry is a promising application where quantum computing might overcome the limitations of known classical algorithms, hampered by an exponential scaling of computational resource requirements. One of the most challenging tasks in quantum chemistry is to determine molecular energies to within chemical accuracy.

At the end of 2018, IonQ announced that they had loaded 79 operating qubits into their trapped ion system and had loaded 160 ions for storage in another test. This new research shows that they are making progress applying their system to useful quantum chemistry problems. They are leveraging the trapped-ions system longer stability to process many steps. The new optimization methods developed for this first major quantum chemistry problem can also be used to solve significant optimization and machine learning problems.

Professor JohnJoe McFadden Quantum Biology — IdeaXme — Ira Pastor


A new chemical process could turn a quarter of our plastic waste into clean fuel

A new chemical process could turn about 90% of the world’s grocery bags, shrink wrap, and other polypropylene waste into clean fuel.

Grocery bags and other trash could be melted down to yield useful products like oil and gas.

The problem: The world’s landfill sites and oceans are being flooded with plastic. A mere 9% of the 8.3 billion tons of plastic produced over the last 65 years has been recycled, according to the United Nations. Over eight million tons of plastic flow into our oceans every year, harming wildlife.

How it works: The technology works on polyolefin waste, the sort of plastic used for grocery bags, toys, and shrink wrap. This sort of plastic accounts for about 23% of plastic waste, according to researchers who describe the process in a paper published in Sustainable Chemistry and Engineering. The new technique uses a process called hydrothermal liquefaction, in which very high temperatures melt pellets of polyolefin and then dissolve them in water. The by-products of this process are oil, gas, or solvents.

Cleaning up the clutter: How proto-biology arose from the prebiotic clutter

‘’We find selection rules driving interactions in chemistry as a result of environmental conditions; or emergent properties such as catalytic activity, self-assembly and self-replication; or even as a result of the specifics of chemical reactions.’’

Just like the mythical creation stories that depict the formation of the world as the story of order from chaos, the early Earth was home to a chaotic clutter of organic molecules from which, somehow, more complex biological structures such as RNA and DNA emerged.

There was no guiding hand to dictate how the molecules within that prebiotic clutter should interact to form life. Yet, had those molecules just interacted randomly then, in all likelihood, that they would never have chanced upon the right interactions to ultimately lead to life.

“The question is, out of all the random possibilities, are there any rules that govern these interactions?” asks Ramanarayanan Krishnamurthy, an organic chemist at the Scripps Research Institute in California.

Plastics are being glued together in the ocean by bacteria, scientists find

Researchers at Heriot-Watt University in Edinburgh used water collected from the Faroe-Shetland Channel and the Firth of Forth to set up their experiments. Plastics were added to the seawater and then incubated in conditions simulating the ocean’s surface. Within minutes, the minuscule pieces of plastic grouped together with bacteria, algae and other organic particles. The scientists are said to have been surprised to discover large masses of biopolymers formed the bulk of these plastic agglomerates. Team member Stephen Summers said: “This is a first step towards understanding how nanoplastics interact with natural biopolymers throughout the world’s oceans. ”This is very important, as it is at this small scale that much of the world’s biogeochemistry occurs. ”We found that the biopolymers envelope or engulf the nanoplastic particles, which caused the plastics to agglomerate into clumps. ”The nanoplastics, which are 100–200 times smaller than a bacterial cell, were actually incorporated into the agglomerates, which became visible to the naked eye in our lab experiments. ”The fact that these agglomerates become large enough to see raises concern, as they are likely to be seen as a food source by small marine animals.” We found that the biopolymers envelope or engulf the nanoplastic particles, which caused the plastics to agglomerate into clumps.

Researchers said micro and nano plastic particles mix with the bacteria secretions within minutes, forming clumps.

Press Association

Celebrate the women behind the periodic table

#HiddenFigures #Friday Here we spotlight some of the women who revolutionized our understanding of the elements. Marie Curie is the most celebrated, for her double Nobel-prizewinning research on radioactivity and for discovering polonium and radium. Stories of other women’s roles are scarce. So, too, is an appreciation of the skills required, including tenacity and diligence in performing experiments, sifting through data and reassessing theories.

Brigitte Van Tiggelen and Annette Lykknes spotlight female researchers who discovered elements and their properties.

New insight into cell membranes could improve drug testing and design

Research at the University of Arkansas on membrane proteins could lead to better development and testing of drugs. Chemistry researchers studied a type of membrane protein that expels drugs from a cell, contributing to drug resistance. They found that the lipid composition of the cell membrane has an effect on the behavior of these proteins, which should be taken into account when testing drugs that target membrane proteins. Their results are available open-access in the journal ACS Central Science.

New scale for electronegativity rewrites the chemistry textbook

Electronegativity is one of the most well-known models for explaining why chemical reactions occur. Now, Martin Rahm from Chalmers University of Technology, Sweden, has redefined the concept with a new, more comprehensive scale. His work, undertaken with colleagues including a Nobel Prize-winner, has been published in the Journal of the American Chemical Society.

The theory of is used to describe how strongly different atoms attract electrons. By using electronegativity scales, one can predict the approximate charge distribution in different molecules and materials, without needing to resort to complex quantum mechanical calculations or spectroscopic studies. This is vital for understanding all kinds of materials, as well as for designing new ones. Used daily by chemists and materials researchers all over the world, the concept originates from Swedish chemist Jöns Jacob Berzelius’ research in the 19th century and is widely taught at high-school level.

Now, Martin Rahm, Assistant Professor in Physical Chemistry at Chalmers University of Technology, has developed a brand-new scale of electronegativity.

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