. Scientific Frontline

Tuesday, February 8, 2022

Self-assembling and complex, nanoscale mesocrystals can be tuned for a variety of uses

A magnified view reveals nanoscale mesocrystals (inset) starting to assemble and form an ordered supracrystal structure, seen in green.
Credit: Inna Soroka

A research team from KTH Royal Institute of Technology and Max Planck Institute of Colloids and Interfaces report to have found the key to controlled fabrication of cerium oxide mesocrystals. The research is a step forward in tuning nanomaterials that can serve a wide range of uses —including solar cells, fuel catalysts and even medicine.

Mesocrystals are nanoparticles with identical size, shape and crystallographic orientation, and they can be used as building blocks to create artificial nanostructures with customized optical, magnetic or electronic properties.

In nature, these three-dimensional structures are found in coral, sea urchins and calcite desert rose. Artificially-produced cerium oxide (CeO2) mesocrystals—or nanoceria—are well-known as catalysts, with antioxidant properties that could be useful in pharmaceutical development.

The early cooling of the universe

A look into the past: Cosmic microwave radiation (left) was released 380,000 years after the Big Bang and serves as the background for all galaxies in the universe. The starburst galaxy HFLS3 (centre) is embedded in a cloud of cold-water vapor and appears as it did 880 million years after the Big Bang. Because of its low temperature, the water casts a dark shadow on the microwave background (detail enlargement on the left). This represents a contrast about 10,000-fold stronger than its intrinsic variations of only 0.001% (light/dark spots). 
Credit: ESA and the Planck Collaboration; zoom-in panel: Dominik Riechers/University of Cologne; image composition: Martina Markus/University of Cologne

The shadow of a cosmic water cloud reveals the temperature of the young universe

A telescope in the French Alps has allowed researchers to peer deep into the past of the universe. For the first time, they were able to observe an extremely distant hydrogen cloud that shadows the cosmic background radiation created shortly after the Big Bang. The shadow is created because the colder water absorbs the warmer background radiation on its way to Earth. This provides information about the temperature of the cosmos just 880 million years after the Big Bang. To measure the early history of the universe, an international team used the Northern Extended Millimeter Array (NOEMA), the most powerful radio telescope in the northern hemisphere.

The universe came into being around 13.8 billion years ago with the Big Bang. At that time, a hot, dense fog of radiation and elementary particles wafted in space, which was rapidly expanding. The density and temperature decreased just as quickly, and the light particles (photons) lost increasingly more energy. After about 380,000 years, this plasma had cooled down to 3000 Kelvin. It was then possible for stable atoms to be created. And the photons had a free path and spread out into space. The cosmos became transparent so to speak.

Don’t lose your marbles: realizing the potential of liquid marbles

Griffith University researchers have solved a problem plaguing droplet-sized micro-reactors which could improve the viability for applications like drug delivery and waste management.

Published in Applied Physics Letters, the technique the team developed uses condensation to noninvasively refill the liquid marbles that previously collapse due to evaporation.

“Liquid marbles are droplets of solution that we wrap in a thin layer of microparticles which can be used for a number of biological, chemical, and biochemical applications,” said co-author Professor Nam-Trung Nguyen from the Queensland Micro and Nanotechnology Centre.

“Liquid marbles are used as microreactors to house various chemical, biochemical and biological purposes like growing cells and applications such as the common PCR, a DNA amplification technique used to detect COVID-19.

“Utilizing liquid marbles for these purposes significantly reduces the amounts of reactants and plastic consumables needed.”

To create the marbles a drop of the reaction solution is rolled over a powder bed of hydrophobic (water resistant) particles or oleophobic (oil resistant) particles, so they create a barrier around the drop that isolates its content from the surrounding.

Dog feces and urine could be harming nature reserves

Sign prohibiting dogs at one of the nature reserves.
Credit: Pieter De Frenne

New research finds that dogs being walked in nature reserves contribute a significant amount of nutrients to the environment through their feces and urine, which researchers warn could negatively impact local biodiversity. The research is published in the British Ecological Society journal, Ecological Solutions and Evidence.

Significant levels of fertilization

Researchers at Ghent University have estimated that each year dog feces and urine add an average of 11kg of nitrogen and 5kg of phosphorous per hectare to nature reserves near the Belgian city of Ghent. The researchers say that the nutrients added through this neglected form of fertilizations are substantial and could be detrimental to biodiversity and ecosystem functioning.

The estimates for the amount of nitrogen being added by this previously unrecorded source are particularly significant when compared to the total levels of nitrogen being added across most of Europe through fossil fuel emissions and agriculture, which range from 5 to 25kg of nitrogen per hectare.

Professor Pieter De Frenne of Ghent University and lead author of the research said: “We were surprised by how high nutrient inputs from dogs could be. Atmospheric nitrogen inputs from agriculture, industry and traffic rightfully receive a lot of policy attention, but dogs are entirely neglected in this respect.”

Five tips for nature-based solutions to combat climate change consequences

The recreational value of a landscape is also taken
 into account in nature-based solutions.
Credit: RUB, Marquard
What works in pilot projects does not have to work in real life.

In order to stop climate change and reduce its consequences, nature-based solutions are well suited: Inspired or supported by nature, they can preserve biodiversity and prevent flooding from flooding. Their implementation works in pilot projects - but how can they be implemented on a large scale under normal conditions? A team from Müncheberg, Hanover, Leipzig, Potsdam and Bochum proposes five principles - among other things, to take advantage of the opportunities of the Corona crisis. The suggestions are on 8. February 2022 published in the magazine npj Urban Sustainability.

Inspired by nature

Nature-based solutions master ecological, social and economic challenges in a way that is inspired or supported by nature. This includes green infrastructure that cushions the effects of climate change in cities, the restoration of meadows and wetlands, the effects of flooding rivers, and measures in agriculture to preserve biodiversity. Many countries see nature-based solutions as a central contribution to reducing and adapting to climate change. They can help achieve global sustainability goals, such as health and well-being, sustainable cities and towns, and sustainable land use.

Mineral dating reveals new clues about important tectonic process

Mantle Peridotite in the Samail Ophiolite, Oman

Ancient rocks on the coast of Oman that were once driven deep down toward Earth’s mantle may reveal new insights into subduction, an important tectonic process that fuels volcanoes and creates continents, according to an international team of scientists.

“In a broad sense this work gives us a better understanding of why some subduction zones fail while others set up as long-term, steady-state systems,” said Joshua Garber, assistant research professor of geosciences at Penn State.

Subduction occurs when two tectonic plates collide, and one is forced under the other. Where oceanic and continental plates meet, the denser oceanic plates normally subduct and descend into the mantle, the scientists said.

Occasionally, oceanic plates move on top, or obduct, forcing continental plates down toward the mantle instead. But the buoyancy of the continental crust can cause the subduction to fail, carrying the material back toward the surface along with slabs of oceanic crust and upper mantle called ophiolites, the scientists said.

“The Samail Ophiolite on the Arabian Peninsula is one of the largest and best exposed examples on the surface of the Earth,” Garber said. “It’s one of the best studied, but there have been disagreements about how and when the subduction occurred.”

Phosphate nutrition of plants through symbiosis with fungi

Prof. Dr. Caroline Gutjahr Professorship for Plant Genetics at the TUM School of Life Sciences, Prof. Dr. Caroline Gutjahr looks at Lotus japonicus seedlings that grow on a petri dish. It stands in front of a climate chamber, in the plant breeding room; The seedlings were subjected to a hairy root transformation with Agrobacterium rhizogenes. This gives transgenic roots for the investigation of molecular processes during the arbusculative mycorrhizal symbiosis. If the plants have grown even more, they are converted into pots and inoculated (stained) with the symbiotic mushroom.
Credit: Uli Benz / TUM

Phosphorus is one of the most important nutrients for plants. Among other functions, it is needed to create substances for the plant’s immune system, for the healthy development of seeds and for root growth. A team of researchers led by the Technical University of Munich (TUM) and the Chinese University of Hong Kong have now demonstrated how a root symbiosis with fungi is driven at the molecular level by the plant’s phosphate status.

Study in mice shows potential for gene-editing to tackle mitochondrial disorders

Mitochondria - 3D illustration 
Credit: wir0man/Getty Images
Our cells contain mitochondria, which provide the energy for our cells to function. Each of these mitochondria contains a tiny amount of mitochondrial DNA. Mitochondrial DNA makes up only 0.1% of the overall human genome and is passed down exclusively from mother to child.

Faults in our mitochondrial DNA can affect how well the mitochondria operate, leading to mitochondrial diseases, serious and often fatal conditions that affect around 1 in 5,000 people. The diseases are incurable and largely untreatable.

There are typically around 1,000 copies of mitochondrial DNA in each cell, and the percentage of these that are damaged, or mutated, will determine whether a person will suffer from mitochondrial disease or not. Usually, more than 60% of the mitochondria in a cell need to be faulty for the disease to emerge, and the more defective mitochondria a person has, the more severe their disease will be. If the percentage of defective DNA could be reduced, the disease could potentially be treated.

A cell that contains a mixture of healthy and faulty mitochondrial DNA is described as ‘heteroplasmic’. If a cell contains no healthy mitochondrial DNA, it is ‘homoplasmic’.

In 2018, a team from the MRC Mitochondrial Biology Unit at the University of Cambridge applied an experimental gene therapy treatment in mice and were able to successfully target and eliminate the damaged mitochondrial DNA in heteroplasmic cells, allowing mitochondria with healthy DNA to take their place.

Sunday, February 6, 2022

Study finds large new source of greenhouse gas emissions

An international team has discovered hundreds of large bursts of methane from oil and gas production activities across the globe. The bursts account for 10% of global oil and gas methane emissions and are missing from most greenhouse gas emissions inventories.

Carbon Mapper, a nonprofit organization that partners with the University of Arizona to mitigate methane and carbon emissions and accelerate climate conservation, contributed to the study, which is published in the journal Science.

The team performed a systematic analysis of thousands of images produced daily by the European Space Agency satellite mission Sentinel-5P to estimate the amount of methane released into the atmosphere by oil and gas production activities.

Over a two-year period, they detected 1,200 "ultra-emitters" attributed to oil and gas facilities and long major transmission pipelines that sporadically release greater than 25 tons of methane per hour over most of the largest oil and gas basins worldwide.

Together, these facilities represent more than 50% of the total onshore natural gas production. Most of these ultra-emitters were short-lived, and many are likely due to planned maintenance activities.

The study revealed that in total, these unreported ultra-emitters contribute to approximately 10% of all methane emissions from the oil and gas sector across the six major oil and gas producing countries – an incredibly large contribution for such a limited number of events.

New highly virulent and damaging HIV variant discovered in the Netherlands

A new HIV variant with higher virulence and more damaging health impacts has been discovered in a study led by the University of Oxford.

As the ongoing coronavirus pandemic has demonstrated, new mutations in viral genetic sequences can have significant impacts on the virus’s transmissibility and the damage it causes. For many years, there have been concerns that this could arise in the HIV-1 virus, which already affects 38 million people worldwide, and has caused 33 million deaths to date (www.unaids.org). This has now been confirmed with the discovery of a new, highly virulent HIV strain in the Netherlands, in an international collaborative study with key contributions from the Dutch HIV Monitoring Foundation and led by researchers from the University of Oxford’s Big Data Institute. The results are published today in Science.

Individuals infected with the new “VB variant” (for virulent subtype B) showed significant differences before antiretroviral treatment compared with individuals infected with other HIV variants:

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