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Category: chemistry – Page 383

Unlocking the secrets of chemical bonding with machine learning

A new machine learning approach offers important insights into catalysis, a fundamental process that makes it possible to reduce the emission of toxic exhaust gases or produce essential materials like fabric.

In a report published in Nature Communications, Hongliang Xin, associate professor of chemical engineering at Virginia Tech, and his team of researchers developed a Bayesian learning model of chemisorption, or Bayeschem for short, aiming to use to unlock the nature of chemical bonding at surfaces.

“It all comes down to how catalysts bind with molecules,” said Xin. “The interaction has to be strong enough to break some at reasonably low temperatures, but not too strong that catalysts would be poisoned by reaction intermediates. This rule is known as the Sabatier principle in catalysis.”

Hidden structure found in essential metabolic machinery

**Peroxisomes are compartments where cells turn fatty molecules into energy and useful materials, like the myelin sheaths that protect nerve cells. In humans, peroxisome dysfunction has been linked to severe metabolic disorders, and peroxisomes may have wider significance for neurodegeneration, obesity, cancer and age-related disorders.**

Peroxisomes are also highly conserved, from plants to yeast to humans, and Bartel said there are hints that these structures may be general features of peroxisomes.

“Peroxisomes are a basic organelle that has been with eukaryotes for a very long time, and there have been observations across eukaryotes, often in particular mutants, where the peroxisomes are either bigger or less packed with proteins, and thus easier to visualize,” she said. But people didn’t necessarily pay attention to those observations because the enlarged peroxisomes resulted from known mutations.

The researchers aren’t sure what purpose is served by the subcompartments, but Wright has a hypothesis.

“When you’re talking about things like beta-oxidation, or metabolism of fats, you get to the point that the molecules don’t want to be in water anymore,” Wright said. “When you think of a traditional kind of biochemical reaction, we just have a substrate floating around in the water environment of a cell—the lumen—and interacting with enzymes; that doesn’t work so well if you’ve got something that doesn’t want to hang around in the water.”

“So, if you’re using these membranes to solubilize the water-insoluble metabolites, and allow better access to lumenal enzymes, it may represent a general strategy to more efficiently deal with that kind of metabolism,” he said.

Bartel said the discovery also provides a new context for understanding peroxisomal disorders.

Continue reading “Hidden structure found in essential metabolic machinery” | >

Dr. Amilcar dos Santos MD — Exploring Far Frontiers of Neural, Spinal, and Brain-Computer Interfaces

Exploring the frontiers of neuromodulation, neurostimulation, and neural interfaces.

Neuromodulation is defined as “the alteration of nerve activity through targeted delivery of a stimulus, such as electrical stimulation or chemical agents, to specific neurological sites in the body”. It is carried out to normalize – or modulate – nervous tissue function.

Neuromodulation is an evolving therapy that can involve a range of electromagnetic stimuli such as a magnetic field, an electric current, or a drug instilled directly in the sub-dural space (i.e. intra-thecal drug delivery).

Emerging applications involve targeted introduction of genes or gene regulators and light (optogenetics), but most clinical experience has been with electrical stimulation.

Existing and emerging neuromodulation treatments also include application in medication-resistant epilepsy, chronic head pain conditions, and functional therapy ranging from bladder and bowel or respiratory control, to improvement of sensory deficits, such as hearing and vision.

Continue reading “Dr. Amilcar dos Santos MD — Exploring Far Frontiers of Neural, Spinal, and Brain-Computer Interfaces” | >

Periodic Table Of The Elements Turns 150

Maybe you’ve felt a certain chemistry with 2019 but don’t know why? Maybe it’s because this year marks the 150th anniversary of the Periodic Table of the Elements. It’s considered the founding document of modern chemistry, one you may have studied in school.

UW-Madison professor of chemistry Bassam Shakhashiri knows both the history of the table, and its modern relevance. He says the table came about through a collaboration of a few scientists but that Dmitri Mendeleev properly gets much of the credit.

“Dimitri Mendeleev, the Russian chemist, he proposed — sometimes people say he discovered — the pattern of similar behavior [of certain elements] and arranged them,” Shakhashiri explains.

Cockroaches Are Rapidly Evolving To Become ‘Almost Impossible’ To Kill

Don’t worry, they aren’t immune to a good slipper…for now.

The rise of the superbug cockroach is upon us. A new study has found that German cockroaches (Blattella germanica) are rapidly evolving to become resistant to many widely used bug sprays and insecticides, as well as chemicals they’ve never been directly exposed to, making them near-impossible to eliminate and one step closer to taking over the world.

Remarkably, the study published in Scientific Reports revealed these scuttling pests could even develop resistance within a single generation. Others also developed cross-resistance, meaning they gained a tolerance to a usually toxic substance just through contact with a similar type of insecticide.

Privacy Overview

Warrior for our planet!

Commissioner Virginijus Sinkevicius:

Commissioner Sinkevičius is the youngest EU Commissioner appointed to the EU Commission. He is a Lithuanian politician, a European Commissioner since 2019. Prior to his appointment as Commissioner, he was the Minister of the Economy and Innovation of the Republic of Lithuania.

Andrea Macdonald founder of ideaXme Commissioner Virginijus Sinkevičius, European Commissioner for the Environment, Oceans and Fisheries.

European Commission:

The Commission helps to shape the EU’s overall strategy, proposes new EU laws and policies, monitors their implementation and manages the EU budget. It also plays a significant role in supporting international development and delivering aid.

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Rivers could generate thousands of nuclear power plants worth of energy, thanks to a new ‘blue’ membrane

There are several ways to generate power from that mixing. And a couple of blue energy power plants have been built. But their high cost has prevented widespread adoption. All blue energy approaches rely on the fact that salts are composed of ions, or chemicals that harbor a positive or negative charge. In solids, the positive and negative charges attract one another, binding the ions together. (Table salt, for example, is a compound made from positively charged sodium ions bound to negatively charged chloride ions.) In water, these ions detach and can move independently.

By pumping the positive ions—like sodium or potassium—to the other side of a semipermeable membrane, researchers can create two pools of water: one with a positive charge, and one with a negative charge. If they then dunk electrodes in the pools and connect them with a wire, electrons will flow from the negatively charged to the positively charged side, generating electricity.

In 2013, French researchers made just such a membrane. They used a ceramic film of silicon nitride—commonly used in industry for electronics, cutting tools, and other uses—pierced by a single pore lined with a boron nitride nanotube (BNNT), a material being investigated for use in high-strength composites, among other things. Because BNNTs are highly negatively charged, the French team suspected they would prevent negatively charged ions in water from passing through the membrane (because similar electric charges repel one another). Their hunch was right. They found that when a membrane with a single BNNT was placed between fresh- and saltwater, the positive ions zipped from the salty side to the fresh side, but the negatively charged ions were mostly blocked.

A strategy to transform the structure of metal-organic framework electrocatalysts

The oxygen evolution reaction (OER) is a chemical process that leads to the generation of molecular oxygen. This reaction is of key importance for the development of clean energy technologies, including water electrolyzers, regenerative fuel cells and rechargeable metal-air batteries.

The extent to which this reaction occurs has so far been limited in many materials, which has restricted the conversion efficiency of some types of technologies. Materials scientists have thus been trying to identify alternative materials, including metals, and hydroxides, that could be used as electrocatalysts to fuel this reaction. The materials identified so far, however, are far from ideal for large-scale implementation, as they are either not particularly resistant or too expensive.

A class of materials widely investigated as possible electrocatalysts for the OER are (MOFs), hybrid and crystalline compounds that consist of a regular array of positively charged metal ions surrounded by organic molecules. While these materials have promising , scientists have yet to identify optimal strategies to enhance their performance.

New family of quasiparticles appears in graphene

Researchers identify Brown-Zak fermions in superlattices made from the carbon sheet.

Researchers at the University of Manchester in the UK have identified a new family of quasiparticles in superlattices made from graphene sandwiched between two slabs of boron nitride. The work is important for fundamental studies of condensed-matter physics and could also lead to the development of improved transistors capable of operating at higher frequencies.

In recent years, physicists and materials scientists have been studying ways to use the weak (van der Waals) coupling between atomically thin layers of different crystals to create new materials in which electronic properties can be manipulated without chemical doping. The most famous example is graphene (a sheet of carbon just one atom thick) encapsulated between another 2D material, hexagonal boron nitride (hBN), which has a similar lattice constant. Since both materials also have similar hexagonal structures, regular moiré patterns (or “superlattices”) form when the two lattices are overlaid.

If the stacked layers of graphene-hBN are then twisted, and the angle between the two materials’ lattices decreases, the size of the superlattice increases. This causes electronic band gaps to develop through the formation of additional Bloch bands in the superlattice’s Brillouin zone (a mathematical construct that describes the fundamental ideas of electronic energy bands). In these Bloch bands, electrons move in a periodic electric potential that matches the lattice and do not interact with one another.

How to make the food and water Mars-bound astronauts will need for their mission

The technology doesn’t seem to be here yet; obviously, the ice on Mars will be harvested to provide drinking and irrigation water.

If we ever intend to send crewed missions to deep-space locations, then we need to come up with solutions for keeping the crews supplied. For astronauts aboard the International Space Station (ISS), who regularly receive resupply missions from Earth, this is not an issue. But for missions traveling to destinations like Mars and beyond, self-sufficiency is the name of the game.

This is the idea behind projects like BIOWYSE and TIME SCALE, which are being developed by the Centre for Interdisciplinary Research in Space (CIRiS) in Norway. These two systems are all about providing astronauts with a sustainable and renewable supply of drinking water and plant food. In so doing, they address two of the most important needs of humans performing long-duration missions that will take them far from home.

Even though the ISS can be resupplied in as little as six hours (the time between launch and the time a supply capsule will dock with the station), astronauts still rely on conservation measures while in orbit. In fact, roughly 80% of the water aboard the ISS comes from airborne water vapor generated by breathing and sweat, as well as recycled shower water and urine—all of which is treated with chemicals to make it safe for drinking.

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