. Scientific Frontline

Wednesday, September 28, 2022

Scientists bring the fusion energy that lights the sun and stars closer to reality on Earth

Physicist Min-Gu Yoo with slides from his paper in background.
Photo credit: Elle Starkman/PPPL Office of Communications; collage by Kiran Sudarsanan

Physicists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have proposed the source of the sudden and puzzling collapse of heat that precedes disruptions that can damage doughnut-shaped tokamak fusion facilities. Coping with the source could overcome one of the most critical challenges that future fusion facilities will face and bring closer to reality the production on Earth of the fusion energy that drives the sun and stars.

Researchers traced the collapse to the 3D disordering of the strong magnetic fields that bottle up the hot, charged plasma gas that fuels the reactions. “We proposed a novel way to understand the [disordered] field lines, which was usually ignored or poorly modeled in the previous studies,” said Min-Gu Yoo, a post-doctoral researcher at PPPL and lead author of a Physics of Plasmas paper selected as an editor’s pick together with a figure placed on the cover of the July issue. Yoo has since become a staff scientist at General Atomics in San Diego.

The strong magnetic fields substitute in fusion facilities for the immense gravity that holds fusion reactions in place in celestial bodies. But when disordered by plasma instability in laboratory experiments the field lines allow the superhot plasma heat to rapidly escape confinement. Such million-degree heat crushes plasma particles together to release fusion energy and can strike and damage fusion facility walls when released from confinement.

Set up reserve lab capacity now for faster response to next pandemic, say researchers

Female scientist in laboratory 
Photo credit: Diane Serik

The researchers, who were on the front line of the UK’s early response to COVID-19 in 2020, say a system of reservist lab scientists should to be set up now to provide surge capacity that will help the country respond faster – and more effectively – to future outbreaks of infectious disease.

They considered a number of options for providing scientific surge capacity and concluded that the best scenario would be a mix of highly skilled paid reservists, and volunteers who could be called on when required and trained rapidly.

In their report, published today in the journal The BMJ, the researchers say the lack of early COVID-19 PCR testing capacity had a knock-on effect on other health services in 2020. This included delaying the ability to make sure hospitals were COVID-secure and patients had surgery as safely as possible, and slowing down the identification of people with COVID-19 in the community – which delayed contact tracing.

“Because COVID-19 testing wasn’t scaled up quickly enough, we couldn’t detect all cases quickly enough to try and stop the spread of the disease,” said Dr Jordan Skittrall in the University of Cambridge’s Department of Pathology and first author of the report.

“It was frustrating to hear politicians’ promises to repeatedly scale up COVID-19 testing capacity during the early stage of the pandemic. The scale-up was extremely challenging: a lot of expertise is needed to get the tests working in the early stages of dealing with a new pathogen,” he added.

Scientists chip away at a metallic mystery, one atom at a time

In this photo from 2020, Christopher Barr, right, a former Sandia National Laboratories postdoctoral researcher, and University of California, Irvine, professor Shen Dillon operate the In-situ Ion Irradiation Transmission Electron Microscope. Barr was part of a Sandia team that used the one-of-a-kind microscope to study atomic-scale radiation effects on metal.
Photo credit: Lonnie Anderson

Gray and white flecks skitter erratically on a computer screen. A towering microscope looms over a landscape of electronic and optical equipment. Inside the microscope, high-energy, accelerated ions bombard a flake of platinum thinner than a hair on a mosquito’s back. Meanwhile, a team of scientists studies the seemingly chaotic display, searching for clues to explain how and why materials degrade in extreme environments.

Based at Sandia, these scientists believe the key to preventing large-scale, catastrophic failures in bridges, airplanes and power plants is to look — very closely — at damage as it first appears at the atomic and nanoscale levels.

“As humans, we see the physical space around us, and we imagine that everything is permanent,” Sandia materials scientist Brad Boyce said. “We see the table, the chair, the lamp, the lights, and we imagine it’s always going to be there, and it’s stable. But we also have this human experience that things around us can unexpectedly break. And that’s the evidence that these things aren’t really stable at all. The reality is many of the materials around us are unstable.”

No difference between spinal versus general anesthesia in patients having hip fracture surgery

Image credit: Fernando zhiminaicela

There are no differences in the safety or effectiveness of the two most common types of anesthetics (spinal versus general anesthesia) in patients undergoing hip fracture surgery, according to the findings of a new study led by the University of Bristol in collaboration with University of Warwick researchers. The findings, published in the British Journal of Anesthesia, analyzed previously published data on nearly 4,000 hip fracture patients.

The research was funded by The Academy of Medical Sciences and supported by the NIHR Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol.

Hip fractures are devastating injuries and remain one of the largest healthcare challenges of the twenty-first century. The incidence increases with advancing age and the number of hip fractures is expected to rise to 6.26 million per year in 2050. In 2017, hip fractures cost the National Health Service (NHS) over £1 billion, which is projected to increase to £5.6 billion in 2033. Patients with hip fractures have a relatively high risk of dying within a year of their injury.

Almost all patients with a hip fracture undergo surgery, requiring anesthesia to be performed so that surgery is safe and not painful. Nearly all patients will receive either spinal or general anesthesia. Given the risk profile of hip fracture patients (older age, frailty, and comorbidities like cardiac and respiratory diseases), surgery is associated with a high risk of developing post-operative complications including delirium, myocardial infarction, pneumonia, stroke, and death.

After wildfires, do microbes exhale potent greenhouse gas?

UCR mycologist and project lead Sydney Glassman sampling burn scar soil.
Photo credit: Sydney Glassman/UCR

Laughing gas is no laughing matter — nitrous oxide is a greenhouse gas with 300 times the warming potential of carbon dioxide. Scientists are racing to learn whether microorganisms send more of it into the atmosphere after wildfires.

A research team led by UC Riverside mycologist Sydney Glassman will spend the next three years answering this question, examining how bacteria, viruses, fungi and archaea work together in post-fire soils to affect nitrous oxide emissions.

Their work is supported by a new $3.1 million grant from the U.S. Department of Energy.

“Because carbon dioxide is the largest contributor to global warming, it’s easy to focus on,” Glassman said.

“Nitrogen in the form of nitrous oxide, and the microbes that regulate it, are a less well-studied aspect of the problem, but an aspect we must solve to more fully understand how the planet is changing, and how much we can expect it to keep changing,” she said.

Novel Carrier Doping in p-type Semiconductors Enhances Photovoltaic Device Performance by Increasing Hole Concentration

The carrier concentration and conductivity in p-type monovalent copper semiconductors can be significantly enhanced by adding alkali metal impurities, as shown recently by Tokyo Tech researchers. Doping with isovalent and larger-sized alkali metal ions effectively increased the free charge carrier concentration and the mechanism was unraveled by their theoretical calculations. Their carrier doping technology enables high carrier concentration and high mobility p-type thin films to be prepared from the solution process, with photovoltaic device applications.

Perovskite solar cells have been the subject of much research as the next generation of photovoltaic devices. However, many challenges remain to be overcome for the practical application. One of them concerns the hole transport layer (p-type semiconductor) in photovoltaic cells that carries holes generated by light to the electrode. In conventional p-type organic transport semiconductors, hole dopants are chemically reactive and degrade the photovoltaic device. Inorganic p-type semiconductors, which are chemically stable, are promising alternatives, but fabrication of conventional inorganic p-type semiconductors requires high temperature treatment. In this regard, the p-type inorganic semiconductors that can be fabricated at low temperatures and have excellent hole transport ability have been desired.

Inorganic p-type copper iodide (CuI) semiconductor is a leading candidate for such hole transport materials in photovoltaic device applications. In this material, native defects give rise to charge imbalance and free charge carriers. However, the overall number of defects is generally too low for satisfactory device performance.

Ural Scientists Propose to Create Citric Acid Using Microorganisms

More than 60% of citric acid is used annually in industry: metallurgy, oil production, medicine and related fields.
Photo credit: Alina Spiridonova

New scientific development will help to create Russia's own production of citric acid, which is currently fully imported. The new method is more technologically advanced and environmentally friendly, as it involves more rational use of microscopic mushrooms for biosynthesis of acid from waste sugar production or products of deep processing of grain. It also avoids large amounts of waste, wastewater and gas emissions. Aleksey Byuler from the UrFU Research Laboratory "Mathematical Modeling in Physiology and Medicine Based on Supercomputers" talked about it on the air of the radio "Komsomolskaya Pravda".

In Russia, the traditional method of citric acid extraction from beet molasses using calcium citrate was used for citric acid production. This led to the formation of significant amounts of waste production: 1 kg of the obtained product had 2 kg of gypsum waste. Such gypsum is not applicable to construction purposes, and its processing requires a lot of energy, so all the gypsum was usually sent to waste, which created a serious impact on the environment. For this reason, the only Russian plant producing citric acid was shut down several years ago. A new linear method using membrane (ultrafiltration) and electrodialysis technologies proposed by the scientists will make it possible to synthesize and isolate citric acid without harming the environment.

Tuesday, September 27, 2022

A Different Kind of Chaos

The experimental setup used by the Weld Lab.
Photo Credit: Tony Mastres

Physicists at UC Santa Barbara and the University of Maryland, and also at the University of Washington have found an answer to the longstanding physics question: How do interparticle interactions affect dynamical localization?

“It’s a really old question inherited from condensed matter physics,” said David Weld, an experimental physicist at UCSB with specialties in ultracold atomic physics and quantum simulation. The question falls into the category of ‘many-body’ physics, which interrogates the physical properties of a quantum system with multiple interacting parts. While many-body problems have been a matter of research and debate for decades, the complexity of these systems, with quantum behaviors such as superposition and entanglement, lead to multitudes of possibilities, making it impossible to solve through calculation alone. “Many aspects of the problem are beyond the reach of modern computers,” Weld added.

Fortunately, this problem was not beyond the reach of an experiment that involves ultracold lithium atoms and lasers. So, what emerges when you introduce interaction in a disordered, chaotic quantum system?

A “weird quantum state,” according to Weld. “It’s a state which is anomalous, with properties which in some sense lie between the classical prediction and the non-interacting quantum prediction.”

The physicists’ results are published in the journal Nature Physics.

Trees get overheated in a warmer rainforest

Maria Wittemann has been conducting field studies in Rwanda with colleagues from the University of Rwanda.
Photo credit: Myriam Mujawamariya

The ability of rainforests to store carbon can decrease in pace with climate change. This is due to photosynthesis rates in the leaves of rainforest species falling at higher temperatures and the trees’ natural cooling systems failing during droughts. Increased heat threatens especially the species that store most carbon. This has been shown in a new thesis from the University of Gothenburg.

Some species of trees are able to handle rising heat in the tropics by sucking up large quantities of water to their leaves and transpiring through wide-opened pores in their leaves. These are mainly fast-growing trees that establish themselves early as a rainforest grows up. The same cannot be said for the trees that make up the canopy of rainforests in old growth forests. They grow slower, but get bigger and taller, and their leaves do not have the same ability to cool themselves via transpiration.

Water powers the ‘air conditioning’

“The tropics have not experienced Ice Ages and have thus had a relatively stable climate historically as well as seasonally. With climate change, it has started to get warmer and then we have seen that some species of trees are showing increased mortality rates, but we have not really known why before,” says Maria Wittemann, who wrote the thesis.

Neurodegenerative disease can progress in newly identified patterns

Neurodegenerative diseases — like amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease), Alzheimer’s, and Parkinson’s — are complicated, chronic ailments that can present with a variety of symptoms, worsen at different rates, and have many underlying genetic and environmental causes, some of which are unknown. ALS, in particular, affects voluntary muscle movement and is always fatal, but while most people survive for only a few years after diagnosis, others live with the disease for decades. Manifestations of ALS can also vary significantly; often slower disease development correlates with onset in the limbs and affecting fine motor skills, while the more serious, bulbar ALS impacts swallowing, speaking, breathing, and mobility. Therefore, understanding the progression of diseases like ALS is critical to enrollment in clinical trials, analysis of potential interventions, and discovery of root causes.

However, assessing disease evolution is far from straightforward. Current clinical studies typically assume that health declines on a downward linear trajectory on a symptom rating scale, and use these linear models to evaluate whether drugs are slowing disease progression. However, data indicate that ALS often follows nonlinear trajectories, with periods where symptoms are stable alternating with periods when they are rapidly changing. Since data can be sparse, and health assessments often rely on subjective rating metrics measured at uneven time intervals, comparisons across patient populations are difficult. These heterogenous data and progression, in turn, complicate analyses of invention effectiveness and potentially mask disease origin.

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