. Scientific Frontline

Thursday, November 18, 2021

Revolution in imaging with neutrons

Instrument scientist Adrian Losko at the neutron radiography instrument NECTAR.
Image Credit: Bernhard Ludewig / FRM II / TUM

An international research team at the Research Neutron Source Heinz Maier-Leibnitz (FRM II) of the Technical University of Munich (TUM) have developed a new imaging technology. In the future this technology could not only improve the resolution of neutron measurements by many times but could also reduce radiation exposure during x-ray imaging.

Modern cameras still rely on the same principle they used 200 years ago: Instead of a piece of film, today an image sensor is exposed for a certain period of time in order to record an image. However, the process also records the noise of the sensor. This constitutes a considerable source of interference especially with longer exposure times.

Together with colleagues from Switzerland, France, the Netherlands and the USA, Dr. Adrian Losko and his TUM colleagues at the Heinz Maier-Leibnitz Zentrum (MLZ) have now developed a new imaging method which measures individual photons on a time-resolved and spatially-resolved basis. This makes it possible to separate photons from noise, greatly reducing the interference.

"Our new detector lets us capture every individual photon and thus overcome many of the physical limitations of traditional cameras," says Dr. Adrian Losko, instrument scientist at the NECTAR neutron radiography facility of the Heinz Maier-Leibnitz Zentrum at the Technical University of Munich.

Research Finds Venom of Cone Snail Could Lead to Future Diabetes Treatments

The cone shell is known for its serene mottled colors but researchers at the
University of New Hampshire found variants of the venom spewed by
the cone snail living inside may offer possibilities for
developing new fast-acting drugs to help treat diabetes.
Photo credit: Wikimedia Commons
The tapered cone shell is popular among seashell collectors for its colorful patterns, but the smooth mottled shells are also home to the cone snail which is capable of spewing a potent insulin-like venom that can paralyze its prey. Researchers at the University of New Hampshire have found that variants of this venom, known as cone snail insulin (Con-Ins), could offer future possibilities for developing new fast-acting drugs to help treat diabetics.

“Diabetes is rising at an alarming rate and it’s become increasingly important to find new alternatives for developing effective and budget-friendly drugs for patients suffering with the disease,” said Harish Vashisth, associate professor of chemical engineering. “Our work found that the modeled Con-Ins variants, or analogs, bind even better to receptors in the body than the human hormone and may work faster which could make them a favorable option for stabilizing blood sugar levels and a potential for new therapeutics.”

In their study, recently published in the journal Proteins: Structure, Function, and Bioinformatics, researchers looked more closely at the cone snail venom which induces a hypoglycemic reaction00 that lowers blood sugar levels. Unlike insulin made in the body, the venom’s peptide sequence - which allows it to bind to human insulin receptors – is much shorter. To test whether it would still bind effectively, the researchers used sequences of the insulin-like peptides in the venom of the cone snail C. geographus as a template to model six different Con-Ins analogs. The newly created variants were made up of much shorter peptide chains than human insulin - lacking the last eight residues of the B-chain of the human insulin.

Wednesday, November 17, 2021

New Technique Improves Conversion of Carbon Dioxide Into Liquid Fuels

Schematic of a two-layer coating of films, called ionomers, on top of a copper surface. The negatively charged ionomer, Nafion, raises the pH near the surface. The positively charged ionomer, Sustainion, more strongly attracts CO2. These effects combined with a pulsed voltage result in substantially enhanced rates of CO2 conversion to valuable carbon-rich products.
Credit: Berkeley Lab

Carbon dioxide (CO2), a product of burning fossil fuels and the most prevalent greenhouse gas, has the potential to be sustainably converted back into useful fuels. A promising route for turning CO2 emissions into a fuel feedstock is a process known as electrochemical reduction. But to be commercially viable, the process needs to be improved, to select for, or to yield, a higher amount of desirable carbon-rich products.

Now, as reported in the journal Nature Energy, researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) have improved the process’s selectivity by developing a new approach to modify the surface of the copper catalysts used to assist the reaction.

“Although we know copper is the best catalyst for this reaction, it doesn’t give high selectivity to the desired products,” said Alexis Bell, a faculty senior scientist in Berkeley Lab’s Chemical Sciences Division and professor of chemical engineering at UC Berkeley. “Our group has found that you can do various tricks with the local environment of the catalyst to provide that selectivity.”

Simple, synthetic structure that mimics surface of SARS-CoV-2 mounts robust immune response in mice

Wei Cheng
In a viral infection, what’s the signal from the virus that alerts the immune system to produce protective neutralizing antibodies?

That’s a big question that scientists seek to answer when trying to understand disease or develop drugs to treat or vaccinate against COVID-19 and other viruses.

“The answer to this question is not simple,” said Wei Cheng, associate professor at the University of Michigan College of Pharmacy. “Most infectious viral agents identified to date are made of complex assemblies of proteins and nucleic acids, along with other constituents that are important for viral fitness and used by viruses to their advantage for replication and proliferation in the infected host.”

To that end, Cheng’s lab developed a simple, synthetic structure that mimics the surface of SARS-CoV-2, that when injected into mice, mounted a robust protective antibody response to SARS-CoV-2, without the need of any other disease fighting agents, called adjuvants. The findings appear in the journal Bioconjugate Chemistry and were featured as an ACS Editors’ Choice. Co-authors are Wei-Yun Wholey, senior staff member, and doctoral student Sekou-Tidiane Yoda.

“This question of what signals an immune response is important for rational design of vaccines and also important for understanding the early events in a viral infection that could be targeted for therapeutic intervention,” Cheng said. “What this result implies is that an ordered assembly of the viral entry protein is all that is needed to initiate an antiviral response. The detailed molecular mechanisms behind this phenomenon remain unclear, but this study made an interesting step forward in our understanding toward viral immunogenicity.”

Research maps milestone stage of human development for the first time

Scientists have shed light on an important stage of early embryonic development that has never been fully mapped out in humans before.

Due to more readily available samples, studies so far have focused on the first week after conception and at later stages beyond a month into pregnancy, during which organs form and mature. However, there is currently very little understanding of events that take place in the intervening days, which includes the crucial gastrulation stage that occurs shortly after the embryo implants in the womb.

Analysis of a unique sample by researchers from the Department of Physiology, Anatomy and Genetics, University of Oxford and Helmholtz Zentrum München helps fill this gap in our knowledge of early human embryogenesis. Their findings, published in the journal Nature, will contribute to the improvement of experimental stem cell models.

Gastrulation is one of the most critical steps of development, and takes place roughly between days 14 and 21 after fertilization. A single-layered embryo is transformed into a multi-layered structure known as the gastrula. During this stage, the three main cell layers that will later give rise to the human body’s tissues, organs and systems are formed. Principal Investigator Professor Shankar Srinivas said: 'Our body is made up of hundreds of types of cells. It is at this stage that the foundation is laid for generating the huge variety of cells in our body – it’s like an explosion of diversity of cell types.'

Feral Hog Invasions Leave Coastal Marshes More Susceptible to Climate Change

Coastal marshes that have been invaded by feral hogs recover from disturbances up to three times slower than non-invaded marshes and are far less resilient to sea-level rise, extreme drought and other impacts of climate change, a new study led by scientists at Duke University and the University of Massachusetts Boston (UMB) finds.

“Under normal circumstances, marshes can handle and recover from drought or sea level rise, given time, but there is no safety net in place for hog invasions,” said Brian Silliman, Rachel Carson Distinguished Professor of Marine Conservation Biology at Duke, who co-authored the study.

“Marshes that are invaded by hogs recover slower from drought, are less resilient to erosion, and hemorrhage carbon dioxide back into the air as hogs turn vast areas of the marsh into mud pits,” Silliman said.

“Based on data from our experiments, our disturbance-recovery model suggests full marsh recovery could take an extra 80 to 100 years,” he said.

Feral hogs are ravenous predators with an insatiable hunger for ribbed mussels, a shellfish species that is one of the most common – and ecologically important – inhabitants of southeastern salt marshes.

There May Be More Bird Species in The Tropics Than We Know

White-crowned Manakin
Image Credit: Phillip Edwards, Macaulay Library, Cornell Lab of ornithology. 
Study of a perky little bird suggests there may be far more avian species in the tropics than those identified so far. After a genetic study of the White-crowned Manakin, scientists say it's not just one species and one of the main drivers of its diversity is the South American landscape and its history of change. These results are published in the journal Molecular Phylogenetics and Evolution. "We found that the White-crowned Manakin probably originated in the highland forests of the Andes Mountains in northern Peru," explains lead author Jacob Berv. "Today, this bird is also found across the Amazon Basin, in the lowland rainforests of Brazil, Peru, and many other countries, including parts of Central America." Berv conducted this research while a Ph.D. student at the Cornell Lab of Ornithology and is currently a Life Sciences Fellow at the University of Michigan. "This study shows that there is a lot of evolutionary history embedded in what is commonly referred to as a 'single widespread' species in Amazonia," says co-author Camila Ribas at Brazil's National Institute of Amazonian Research. "The White-crowned Manakin is an example of a phenomenon that is probably more the rule than the exception in Amazonia—diversity is vastly underestimated by the current taxonomy."

Food waste at East Coast Lagoon Food Village to be turned into energy and fertilizer under pilot project

Associate Professor Tong Yen Wah, who leads the NUS team,
is pictured next to the anaerobic digester at the
East Coast Lagoon Food Village.
An anaerobic digestion system for food waste treatment is being piloted at the East Coast Lagoon Food Village. The system was developed by a team of researchers from the National University of Singapore (NUS) and converts food waste generated by food stalls and patrons at East Coast Lagoon Food Village into biogas and bio-fertilizer. A biogas engine converts the biogas into electricity, while the bio-fertilizer is used in landscaping applications. The onsite treatment of food waste reduces the need to send food waste for incineration.

Food waste is one of the priority waste streams identified under Singapore’s Zero Waste Masterplan. In 2020, food waste accounted for about 11 per cent of the total waste generated in Singapore, but only 19 per cent of the food waste was recycled. The rest of it was disposed of at waste-to-energy (WTE) plants. Therefore, reducing food wastage, redistributing unsold or excess food, and recycling/treating food waste are important food waste management strategies. Food waste needs to be managed holistically, as it can contaminate other recyclables when they are disposed of together, making the recyclables unsuitable or difficult to recycle. It can also give rise to odor nuisance and vermin proliferation issues, if not managed properly or in a timely manner.

As part of efforts to treat food waste and demonstrate the feasibility of on-site food waste treatment, the National Environment Agency (NEA) is supporting NUS in conducting a pilot trial of their containerized Anaerobic Digestion system at East Coast Lagoon Food Village, under the Closing the Waste Loop (CTWL) R&D Initiative. The NUS team, led by Associate Professor Tong Yen Wah from the NUS Department of Chemical and Biomolecular Engineering, oversees the operation and maintenance of the Anaerobic Digestion system. The team is concurrently studying the human psychology and behavioral factors in encouraging hawkers and cleaners to segregate food waste from other waste.

Fraternizing vampire bats share 'social microbiomes'

Microbes that make their homes on the skin or in the digestive tracts of animals can be beneficial or pathogenic to the individual and to the community. A new study finds that the gut microbiomes of vampire bats become more similar the more often the bats engage in social behaviors with one another.  Image Credit: Uwe Schmidt
In an unusual study, researchers brought vampire bats from distant Panamanian populations together for four months in a laboratory setting and tracked how the bats’ gut microbes changed over time. They found that bats that interacted closely with one another shared much more than body heat.

Reported in the journal Biology Letters, the study revealed that the gut microbiomes of bats became more similar the more often they engaged in social behaviors with one another. Such behaviors included huddling together for warmth, grooming themselves and their neighbors, and – in rare cases – sharing food via regurgitation.

This is the first study of social microbiomes to control for other factors – such as diet and environment – that could contribute to microbiome similarities, the researchers said. The study kept all the bats together in one enclosure and the bats consumed the same, laboratory-prepared food: cattle and pig blood.

Tuesday, November 16, 2021

Research Reveals How to Design a Better Next-Generation Lithium-Ion Battery

A solid-state lithium-ion battery is composed of an anode, a cathode, and a solid electrolyte separating the two. Rapidly cycling (repeatedly charging and discharging) a lithium-ion battery limits the battery's performance over time by significantly increasing the battery's internal impedance (its time-dependent resistance), which hinders the flow of current. NIST researchers, in collaboration with Sandia National Laboratories, have combined two complementary techniques – contact potential difference measurements and neutron depth profiling – to precisely determine which parts of the battery contribute most to its impedance. 
Credit: S. Kelley/NIST

The newest generation of lithium-ion batteries now under development promises a revolution in powering cell phones, electric vehicles, laptops and myriad other devices. Featuring all solid-state, nonflammable components, the new batteries are lighter, hold their charge longer, recharge faster and are safer to use than conventional lithium-ion batteries, which contain a gel that can catch on fire.

However, like all batteries, solid-state lithium-ion batteries have a drawback: Due to electro-chemical interactions, impedance--the AC analog of DC electrical resistance--can build up within the batteries, limiting the flow of electric current. Researchers at the National Institute of Standards and Technology (NIST) and their colleagues have now pinpointed the location where most of this buildup occurs. In so doing, the team has suggested a simple redesign that could dramatically limit the buildup of impedance, enabling the batteries to fulfill their role as the next-generation power source.

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