New frontier for 3D printing developed state-of-the-art soft materials able to self-heal

Research by the MP4MNT (Materials and Processing for Micro and Nanotechnologies) team of the Politecnico di Torino published in the journal Nature Communication

POLITECNICO DI TORINO

Research News

 

The scientific community is focusing its research into the multiple applications of Hydrogels, polymeric materials which contains a large amount of water, that have the potential to reproduce the features of biological tissues. This aspect is particularly significant in the field of regenerative medicine, which since a long time has already recognised and been using the characteristics of these materials. In order to be used effectively to replace organic tissues, hydrogels must meet two essential requirements: possessing great geometric complexity and, after suffering of a damage, being able to self-heal independently, exactly like living tissues.

The development of these materials may now be easier, and cheaper, thanks to the use of 3D printing: the researchers in the MP4MNT (Materials and Processing for Micro and Nanotechnologies) team of the Department of Applied Science and Technology of the Politecnico di Torino, coordinated by Professor Fabrizio Pirri, have demonstrated, for the first time, the possibility of manufacturing hydrogels with complex architectures capable of self-healing following a laceration, thanks to 3D printing activated by light. The research was published by the prestigious journal Nature Communication in an article entitled "3D-printed self-healing hydrogels via Digital Light Processing" (DOI 10.1038/s41467-021-22802-z).

Up to now, hydrogels either with self-healing properties or modellable in complex architectures using 3D printing, had already been created in the laboratory, but in the present case, the discovered solution encompasses both features: architectural complexity and the ability to self-heal following damage. In addition, the hydrogel was created using materials available on the market, processed using a commercial printer, thus making the approach proposed extremely flexible and potentially applicable anywhere, opening new possibilities for development both in the biomedical and soft-robotics fields.

The research was carried out in the context of the HYDROPRINT3D doctoral project, funded by the Compagnia di San Paolo, in the frame of "Joint Research Projects with Top Universities" initiative, by the PhD student Matteo Caprioli, under the supervision of the DISAT researcher Ignazio Roppolo, in collaboration with Professor Magdassi's research group of the Hebrew University of Jerusalem (Israel).

"Since many years", Ignazio Roppolo recounts, "in the MP4MNT group, a research unit coordinated by Dr Annalisa Chiappone and I is specifically devoted to development of new materials that can be processed using 3D printing activated by light. 3D printing is able to offer a synergistic effect between the design of the object and the intrinsic properties of materials, making possible to obtain manufactured items with unique features. From our perspective, we need to take advantage of this synergy to best develop the capabilities of 3D printing, so that this can truly become an element of our everyday life. And this research falls right in line with this philosophy".

This research represents a first step towards the development of highly complex devices, which can exploit both the complex geometries and the intrinsic self-healing properties in various application fields. In particular, once the biocompatibility studies underway at the interdepartmental laboratory PolitoBIOMed Lab of the Politecnico have been refined, it will be possible to use these objects both for basic research into cellular mechanisms and for applications in the field of regenerative medicine.

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Processed diets might promote chronic infections that can lead to disorders such as diabetes

GEORGIA STATE UNIVERSITY

Research News

ATLANTA--Processed diets, which are low in fiber, may initially reduce the incidence of foodborne infectious diseases such as E. coli infections, but might also increase the incidence of diseases characterized by low-grade chronic infection and inflammation such as diabetes, according to researchers in the Institute for Biomedical Sciences at Georgia State University.

This study used mice to investigate how changing from a grain-based diet to a highly processed, high-fat Western style diet impacts infection with the pathogen Citrobacter rodentium, which resembles Escherichia coli (E. coli) infections in humans. The findings are published in the journal PLOS Pathogens.

Gut microbiota, the microorganisms living in the intestine, provide a number of benefits, such as protecting a host from infection by bacterial pathogens. These microorganisms are influenced by a variety of environmental factors, especially diet, and rely heavily on complex carbohydrates such as fiber.

The Western-style diet, which contains high amounts of processed foods, red meat, high-fat dairy products, high-sugar foods and pre-packaged foods, lacks fiber, which is needed to support gut microbiota. Changes in dietary habits, especially a lack of fiber, are believed to have contributed to increased prevalence of chronic inflammatory diseases such as inflammatory bowel disease, metabolic syndrome and cancer.

In this study, the researchers found switching mice from a standard grain-based rodent chow to a high-fat, low-fiber Western-style diet resulted in a rapid reduction in the number of gut bacteria. Mice fed the Western-style diet were frequently unable to clear the pathogen Citrobacter rodentium from the colon. They were also prone to developing chronic infection when re-challenged by this pathogen.

The researchers conclude the Western-style diet reduces the numbers of gut bacteria and promotes encroachment of microbiota into the intestine, potentially influencing immune system readiness and the body's defense against pathogenic bacteria.

"We observed that feeding mice a Western-style diet, rather than standard rodent grain-based chow, altered the dynamics of Citrobacter infection, reducing initial colonization and inflammation, which was surprising. However, mice consuming the Western-style diet frequently developed persistent infection that was associated with low-grade inflammation and insulin resistance," said Dr. Andrew Gewirtz, senior co-author of the study and professor in the Institute for Biomedical Sciences. "These studies demonstrate potential of altering microbiota and their metabolites by diet to impact the course and consequence of infection following exposure to a gut pathogen."

"We speculate that reshaping gut microbiota by nutrients that promote beneficial bacteria that out-compete pathogens may be a means of broadly promoting health," said Dr. Jun Zou, senior co-author of the study and assistant professor in the Institute for Biomedical Sciences at Georgia State.

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Additional co-authors of the study include Junqing An, Xu Zhao, Yanling Wang and Juan Noriega.

The study was funded by the National Institutes of Health and the American Diabetes Association.

To read the study, visit https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1009497.

 

Using nanobodies to block a tick-borne bacterial infection

In cells and mice, tiny molecules stop bacteria from hijacking cells

OHIO STATE UNIVERSITY

Research News

 

COLUMBUS, Ohio - Tiny molecules called nanobodies, which can be designed to mimic antibody structures and functions, may be the key to blocking a tick-borne bacterial infection that remains out of reach of almost all antibiotics, new research suggests.

The infection is called human monocytic ehrlichiosis, and is one of the most prevalent and potentially life-threatening tick-borne diseases in the United States. The disease initially causes flu-like symptoms common to many illnesses, and in rare cases can be fatal if left untreated.

Most antibiotics can't build up in high enough concentrations to kill the infection-causing bacteria, Ehrlichia chaffeensis, because the microbes live in and multiply inside human immune cells. Commonly known bacterial pathogens like Streptococcus and E. coli do their infectious damage outside of hosts' cells.

Ohio State University researchers created nanobodies intended to target a protein that makes E. chaffeensis bacteria particularly infectious. A series of experiments in cell cultures and mice showed that one specific nanobody they created in the lab could inhibit infection by blocking three ways the protein enables the bacteria to hijack immune cells.

"If multiple mechanisms are blocked, that's better than just stopping one function, and it gives us more confidence that these nanobodies will really work," said study lead author Yasuko Rikihisa, professor of veterinary biosciences at Ohio State.

The study provided support for the feasibility of nanobody-based ehrlichiosis treatment, but much more research is needed before a treatment would be available for humans. There is a certain urgency to coming up with an alternative to the antibiotic doxycycline, the only treatment available. The broad-spectrum antibiotic is unsafe for pregnant women and children, and it can cause severe side effects.

"With only a single antibiotic available as a treatment for this infection, if antibiotic resistance were to develop in these bacteria, there is no treatment left. It's very scary," Rikihisa said.

The research is published this week in Proceedings of the National Academy of Sciences.

The bacteria that cause ehrlichiosis are part of a family called obligatory intracellular bacteria. E. chaffeensis not only requires internal access to a cell to live, but also blocks host cells' ability to program their own death with a function called apoptosis - which would kill the bacteria.

"Infected cells normally would commit suicide by apoptosis to kill the bacteria inside. But these bacteria block apoptosis and keep the cell alive so they can multiply hundreds of times very rapidly and then kill the host cell," Rikihisa said.

A longtime specialist in the Rickettsiales family of bacteria to which E. chaffeensis belongs, Rikihisa developed the precise culture conditions that enabled growing these bacteria in the lab in the 1980s, which led to her dozens of discoveries explaining how they work. Among those findings was identification of proteins that help E. chaffeensis block immune cells' programmed cell death.

The researchers synthesized one of those proteins, called Etf-1, to make a vaccine-style agent that they used to immunize a llama with the help of Jeffrey Lakritz, professor of veterinary preventive medicine at Ohio State. Camels, llamas and alpacas are known to produce single-chain antibodies that include a large antigen binding site on the tip.

The team snipped apart segments of that binding site to create a library of nanobodies with potential to function as antibodies that recognize and attach to the Etf-1 protein and stop E. chaffeensis infection.

"They function similarly to our own antibodies, but they're tiny, tiny nano-antibodies," Rikihisa said. "Because they are small, they get into nooks and crannies and recognize antigens much more effectively.

"Big antibodies cannot fit inside a cell. And we don't need to rely on nanobodies to block extracellular bacteria because they are outside and accessible to ordinary antibodies binding to them."

After screening the candidates for their effectiveness, the researchers landed on a single nanobody that attached to Etf-1 in cell cultures and inhibited three of its functions. By making the nanobodies in the fluid inside E. coli cells, Rikihisa said her lab could produce them at an industrial scale if needed - packing millions of them into a small drop.

She collaborated with co-author Dehua Pei, professor of chemistry and biochemistry at Ohio State, to combine the tiny molecules with a cell-penetrating peptide that enabled the nanobodies to be safely delivered to mouse cells.

Mice with compromised immune systems were inoculated with a highly virulent strain of E. chaffeensis and given intracellular nanobody treatments one and two days after infection. Compared to mice that received control treatments, mice that received the most effective nanobody showed significantly lower levels of bacteria two weeks after infection.

With this study providing the proof of principle that nanobodies can inhibit E. chaffeensis infection by targeting a single protein, Rikihisa said there are multiple additional targets that could provide even more protection with nanobodies delivered alone or in combination. She also said the concept is broadly applicable to other intracellular diseases.

"Cancers and neurodegenerative diseases work in our cells, so if we want to block an abnormal process or abnormal molecule, this approach may work," she said.

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This study was supported by the National Institutes of Health.

Additional co-authors, all from Ohio State, include Wenqing Zhang, Mingqun Lin, Qi Yan, Khemraj Budachetri, Libo Hou, Ashweta Sahni, Hongyan Liu and Nien-Ching Han.

Contact: Yasuko Rikihisa, Rikihisa.1@osu.edu

Written by Emily Caldwell, Caldwell.151@osu.edu

Uncertainty of future Southern Ocean CO2 uptake cut in half

UNIVERSITY OF BERN

Research News

 

IMAGE: SALINITY MEASUREMENTS IN THE SOUTHERN OCEAN ARE KEY TO REDUCE UNCERTAINTY IN MODEL PROJECTIONS OF ANTHROPOGENIC CO2 UPTAKE. view more 

CREDIT: © OSCAR SCHOFIELD, RUTGERS UNIVERSITY

Anyone researching the global carbon cycle has to deal with unimaginably large numbers. The Southern Ocean - the world's largest ocean sink region for human-made CO2 - is projected to absorb a total of about 244 billion tons of human-made carbon from the atmosphere over the period from 1850 to 2100 under a high CO2 emissions scenario. But the uptake could possibly be only 204 or up to 309 billion tons. That's how much the projections of the current generation of climate models vary. The reason for this large uncertainty is the complex circulation of the Southern Ocean, which is difficult to correctly represent in climate models.

"Research has been trying to solve this problem for a long time. Now we have succeeded in reducing the great uncertainty by about 50 percent," says Jens Terhaar of the Oeschger Centre for Climate Change Research at the University of Bern.

Together with Thomas Frölicher and Fortunat Joos, who are also researchers at the Oeschger Centre, Terhaar has just presented in the scientific journal "Sciences Advances" a new method for constraining the Southern Ocean's CO2 sink. The link between the uptake of human-made CO2 and the salinity of the surface waters is key to this. "The discovery that these two factors are closely related helped us to better constrain the future Southern Ocean CO2 sink " explains Thomas Frölicher.

Towards achieving the Paris climate target

A better constraint Southern Ocean carbon sink is a prerequisite to understand future climate change. The ocean absorbs at least one fifth of human-made CO2 emissions, and as such slows down global warming. By far the largest part of this uptake, about 40 percent, occurs in the Southern Ocean.

The new calculations from Bern not only reduce uncertainties in CO2 uptake and thus allow more accurate projections, but also show that by the end of the 21st century the Southern Ocean will absorb around 15 percent more CO2 than previously thought. This is only a tiny bit of help on the extremely challenging path to achieving the Paris temperature goal of 1.5 degree. "The reduction of human-made CO2 emissions resulting from the combustion of fossil fuels remains extremely urgent if we are to achieve the goals of the Paris climate agreement," clarifies Fortunat Joos.

Better model predictions possible

In their study, the three climate scientists show why the salinity content of the ocean surface waters is a good indicator of how much human-made CO2 is transported into the ocean interior. Models that simulate low salinity in the Southern Ocean surface waters have too light waters and therefore transport less water and CO2 into the ocean interior. As a result, they also absorb less CO2 from the atmosphere. Models with higher salinity, on the other hand, show higher absorption of CO2 from the atmosphere. The salinity of the Southern Ocean surface waters, determined through observations, allowed the researchers from Bern to narrow down the uncertainty in the various model projections.

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Publication details:

J. Terhaar, T. L. Frölicher, F. Joos: Southern Ocean anthropogenic carbon sink constrained by sea surface salinity. Sci. Adv. 7, eabd5964 (2021), April 28, 2021, doi: 10.1126/sciadv.abd5964 https://advances.sciencemag.org/content/7/18/eabd5964

Oeschger Centre for Climate Change Research

The Oeschger Centre for Climate Change Research (OCCR) is one of the strategic centers of the University of Bern. It brings together researchers from 14 institutes and four faculties. The OCCR conducts interdisciplinary research right on the frontline of climate change research. The Oeschger Centre was founded in 2007 and bears the name of Hans Oeschger (1927-1998), a pioneer of modern climate research, who worked in Bern. http://www.oeschger.unibe.ch

 

Wasps are valuable for ecosystems, economy and human health (just like bees)

UNIVERSITY COLLEGE LONDON

Research News

 

IMAGE: SOCIAL PAPER WASP (POLISTES SATAN) PREDATING ON FALL ARMY WORM view more 

CREDIT: PROFESSOR SEIRIAN SUMNER, UCL

Wasps deserve to be just as highly valued as other insects, like bees, due to their roles as predators, pollinators, and more, according to a new review paper led by UCL and University of East Anglia researchers.

The study, published in Biological Reviews, compiles evidence from over 500 academic papers to review how roughly 33,000 species of stinging (aculeate) wasps contribute to their ecosystems, and how this can benefit the economy, human health, and society.

Lead author Professor Seirian Sumner (UCL Centre for Biodiversity & Environment Research, UCL Biosciences) said: "Wasps are one of those insects we love to hate - and yet bees, which also sting, are prized for pollinating our crops and making honey. In a previous study, we found that the hatred of wasps is largely due to widespread ignorance about the role of wasps in ecosystems, and how they can be beneficial to humans.

"Wasps are understudied relative to other insects like bees, so we are only now starting to properly understand the value and importance of their ecosystem services. Here, we have reviewed the best evidence there is, and found that wasps could be just as valuable as other beloved insects like bees, if only we gave them more of a chance."

Wasps are top predators of other insects. Predation by insects - as biocontrol to protect crops - is worth at least $416 billion (US) per year worldwide. Yet, this figure almost completely overlooks the contributions of hunting wasp predation. The review highlights how wasps' role as predators makes them valuable for agriculture. Wasps regulate populations of arthropods, like aphids and caterpillars that damage crops. Solitary wasp species tend to be specialists, which may be suited to managing a specific pest, while social wasps are generalist predators, and may be especially useful as a local source of control for a range of crop-eating pests.

The researchers say that wasps could be used as sustainable forms of pest control in developing countries, especially tropical ones, where farmers could bring in populations of a local wasp species with minimal risk to the natural environment. Professor Sumner and colleagues recently published a study finding that common wasp species are effective predators that can manage pests on two high-value crops, maize and sugarcane, in Brazil.

The review also highlights the pollination services provided by wasps. Pollination by insects is vital for agriculture, and its economic importance has been valued at greater than $250 billion (US) per year worldwide.

The researchers found evidence of wasps visiting 960 plant species. This included 164 species that are completely dependent on wasps for pollination, such as some orchid species that have evolved adaptations to attract the wasps they rely on, such as an appearance that mimics the back end of a female wasp. Many wasps are also generalist pollinators that visit a wide variety of plants, so the researchers say they could serve as 'backup pollinators' if a plant loses its local primary pollinator.

The review also describes other uses for wasps such as wasp-derived medications, as their venom and saliva have antibiotic properties, while yellowjacket wasp venom has shown promise in treating cancer. Wasps may even be a valuable food source, as their larvae are already harvested in some tropical countries for food.

Co-author Dr Alessandro Cini (UCL Centre for Biodiversity & Environment Research, UCL Bioscience and University of Florence) said: "The value of wasps in supporting our crops remains poorly understood; we hope that by rehabilitating their bad reputation, we can collectively get the most value out of these fascinating creatures."

The paper's first author, Ryan Brock (University of East Anglia) said: "Alongside other insects, many wasp species are declining from factors such as climate change and habitat loss. As such, there is urgent need to address their conservation and ensure that habitats continue to benefit from the far-reaching ecosystem services that wasps provide."

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The research was supported by the Natural Environment Research Council and a Marie Curie fellowship from the European Commission.

CAPTION

Social paper wasp (Polistes satan) with pest larva

CREDIT

Professor Seirian Sumner, UCL

Hidden air pollutants on the rise in cities in India and the UK - study

UNIVERSITY OF BIRMINGHAM

Research News

 

Levels of air pollutants in cities in India are on the rise, according to scientists using observations from instruments on satellites that scan the global skies every day.

Researchers used a long record of data gathered by space-based instruments to estimate trends in a range of air pollutants for 2005 to 2018, timed to coincide with well-established air quality policies in the UK and rapid development in India.

The study was led by the University of Birmingham and UCL and included an international team of contributors from Belgium, India, Jamaica and the UK. The researchers published their findings in the journal Atmospheric Chemistry and Physics, noting that fine particles (PM2.5) and nitrogen dioxide (NO2), both hazardous to health, are increasing in Kanpur and Delhi.

Delhi is a fast-growing megacity and Kanpur was ranked by the WHO in 2018 as the most polluted city in the world. The researchers speculated that increases in PM2.5 and NO2 in India reflect increasing vehicle ownership, industrialisation and the limited effect of air pollution policies to date.

This contrasts with trends in the UK cities London and Birmingham, which show modest but ongoing declines in PM2.5 and NOx, reflecting the success of policies targeting sources that emit these pollutants.

They also found increases in the air pollutant formaldehyde in Delhi, Kanpur and London. Formaldehyde is a marker for emissions of volatile organic compounds that include a large contribution from vehicle emissions in India, and, in the UK, an increasing contribution from personal care and cleaning products and a range of other household sources.

Karn Vohra, study lead author and PhD student at the University of Birmingham, commented: "We wanted to demonstrate the utility of satellite observations to monitor city-wide air pollution in the UK where ground-based measurements are in abundance and in India where they are not. Our approach will be able to provide useful information about air quality trends in cities with limited surface monitoring capabilities. This is critical as the WHO estimates that outdoor air pollution causes 4.2 million deaths a year."

Study co-author Professor William Bloss, also from the University of Birmingham, commented "We were surprised to see the increase in formaldehyde above Delhi, Kanpur and London - a clue that emissions of other volatile organic compounds may be changing, potentially driven by economic development and changes in domestic behaviour. Our results emphasise the need to monitor our air for the unexpected, and the importance of ongoing enforcement of measures for cleaner air."

"There is more than a decade of freely available observations from instruments in space to monitor and assess air quality in cities throughout the world. Greater use of these in the UK, India, and beyond is paramount to successful air quality policies", stated Dr Eloise Marais, Earth observation expert at UCL and conceptual lead of the study.

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For more information, interviews or an embargoed copy of the research paper, please contact Tony Moran, International Communications Manager, University of Birmingham on +44 (0)782 783 2312 or t.moran@bham.ac.uk. For out-of-hours enquiries, please call +44 (0) 7789 921 165.

Notes to Editors

* The University of Birmingham is ranked amongst the world's top 100 institutions, its work brings people from across the world to Birmingham, including researchers and teachers and more than 6,500 international students from over 150 countries.

* 'Long-term trends in air quality in major cities in the UK and India: A view from space' - Karn Vohra, Eloise A. Marais, Shannen Suckra, Louisa Kramer, William J. Bloss, Ravi Sahu, Abhishek Gaur, Sachchida N. Tripathi, Martin Van Damme, Lieven Clarisse and Pierre F. Coheur is published in Atmospheric Chemistry and Physics.

* Partner research institutions include: University of Birmingham; University College London; University of Leicester; Indian Institute of Technology Kanpur; Université libre de Bruxelles (ULB), Belgium; National Environment & Planning Agency, Kingston, Jamaica and Ricardo Energy & Environment, Harwell, UK

New report highlights the benefits of bringing nature into our cities

BRITISH ECOLOGICAL SOCIETY

Research News

 

The report highlights planting urban trees, increasing community green spaces, utilising brownfield sites and building sustainable drainage systems as effective nature-based solutions in cities to improve wellbeing, bring economic benefit, increase biodiversity and fight climate change.

These conclusions, released today (29 April), form part of the Nature-based Solutions report produced by the British Ecological Society which will be published in full on the 12th May. The report will offer, for the first time, a complete assessment of the potential of nature-based solutions to mitigate climate change and benefit biodiversity in the UK.

Our cities and towns may not seem an obvious place to tackle climate change and biodiversity loss. But the high concentration of people mean that nature-based solutions can have significant and direct impacts on people's lives.

Professor Marc Cadotte of University of Toronto-Scarborough and lead author of the built environment chapter of the report said: "Cities are a place where most people interact with nature so improving this environment with nature-based solutions makes a lot of sense. Any space, no matter how small, has value and can have a major contribution to environmental wellbeing.

"The multiple benefits that nature-based solutions bring to cities are inseparable from each other. For example, a project to improve biodiversity in a park will also directly benefit local people, providing access to nature and the wellbeing benefits associated with that."

A key message from the authors' assessment of all the evidence is that there is no single nature-based solution that should be applied to cities. Multiple approaches are needed across different contexts and these need to be diverse, multifaceted and inclusive.

Professor Cadotte added "The implementation of nature-based solutions in cities is inherently complex and at odds with siloed governance structures. Unified top-level vision is needed to coordinate nature-based solutions across disparate agencies in urban areas, such as parks, construction and sewerage."

Examples of nature-based solutions

The report reviews a wide range of evidence to highlight several ways nature-based solutions can be used to tackle the sustainability and resilience challenges our cities face, such as air pollution, rising temperatures, flood risk and a disconnect with the natural world.

Storing carbon

The report finds that urban areas have substantial potential for carbon capture. One case featured in the report found that despite the city Leicester covering 0.03% of Britain's land area, it accounts for approximately 0.2% of Britain's aboveground carbon store, with over 97% of this is attributable to trees.

Urban soils can also act as an important carbon sink if managed correctly. The retention of fine material derived from demolition on urban brownfield land can result in carbon sequestration. Providing a source of calcium, in the form of crushed concrete or other sources to just 1% of the UK's urban and suburban soils could remove up to 1 million tonnes carbon dioxide annually.

Providing shade

Planting urban trees can also help cool cities and mitigate air pollution. UK cities already experience average day and night temperatures 1 to 3°C warmer than surrounding natural and agricultural areas. Urban temperatures and the frequency of extreme heatwaves in the UK are predicted to increase.

Nature-based solutions such as planting street trees and green roofs can reduce urban temperatures through shading and the movement of water to the air (termed evapotranspiration). In Greater London, current greenspace reduces temperatures by over 0.5°C on clear, still and warm nights.

Removing particulates

40,000 premature deaths each year are attributable to exposure to outdoor air pollution in the UK, and cities are focal points for the production of these pollutants. The report details how urban trees and other vegetation can both sequester carbon dioxide and intercept airborne particulate matter (PM) and other aerial emissions. Modelling in Glasgow has shown that current tree cover in the city removes 3% of the primary particulate matter.

Reducing flood risk while benefiting biodiversity

Storms and the severe flooding they cause are predicted to become more frequent. Sustainable drainage systems which include wetlands, swales and raingardens can be combined with green roofs, urban forests and meadows to reduce flood surges and mover water safely.

By incorporating these features into our built environments, we also encourage greater biodiversity and there is the potential to support rare species. For example, in London, the building of green roofs has provided habitats for black redstarts. Brownfields can also be used to mimic many of the traditional habitats used by rare butterflies.

Access to green space

Nature-based solutions in cities can also help solve a disconnect many urban populations have with nature, as well as improve health and wellbeing. Green spaces are known to reduce stress and increase physical activity while the presence of urban forests has been shown to reduce incidence of cardiovascular and pulmonary disease.

Access to green space is often a socio-economic issue with marginalised communities having less access. Brownfield sites are common in areas of high deprivation and the report highlights that through working with local communities, nature-based solutions can turn these sites into resilient, accessible, and useable assets that provide considerable health, economic, climate and biodiversity benefits.

Economic benefits

Nature-based solutions can also provide considerable economic benefits through improved population health, climate change mitigation and green job creation. Attempts to account for the monetary value of ecosystem benefits have shown that natural systems add millions of pounds of value to cities. For instance, Birmingham valued its ecosystem services at £11.66 million per year, recognising that this was a substantial undervaluation. The City of London calculated the annual economic contribution of its eight million trees to be £132.7 million annually, equalling about £15 per tree.

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Using cosmic-ray neutron bursts to understand gamma-ray bursts from lightning

An 'accidental discovery' confirms what simulations show

DOE/LOS ALAMOS NATIONAL LABORATORY

Research News

 

IMAGE: A LIGHTNING MAPPER AT THE HIGH ALTITUDE WATER CHERENKOV (HAWC) COSMIC RAY OBSERVATORY IN MEXICO UNEXPECTEDLY OBSERVED THAT GAMMA RAYS PRODUCE MORE NEUTRONS THAN PREVIOUSLY KNOWN. view more 

CREDIT: JORDAN GOODMAN, HAWC COLLABORATION (NSF.GOV)

LOS ALAMOS, N.M., April 28, 2021--Analysis of data from a lightning mapper and a small, hand-held radiation detector has unexpectedly shed light on what a gamma-ray burst from lightning might look like - by observing neutrons generated from soil by very large cosmic-ray showers. The work took place at the High Altitude Water Cherenkov (HAWC) Cosmic Ray Observatory in Mexico.

"This was an accidental discovery," said Greg Bowers, a scientist at Los Alamos National Laboratory and lead author of the study published in Geophysical Research Letters. "We set up this system to study terrestrial gamma-ray flashes - or gamma-ray bursts from lightning - that are typically so bright you can see them from space. The idea was that HAWC would be sensitive to the gamma-ray bursts, so we installed a lightning mapper to capture the anatomy of the lightning development and pinpoint the lightning processes producing them."

The team, including Xuan-Min Shao and Brenda Dingus also from Los Alamos, used a small, handheld particle detector, expecting that a terrestrial gamma-ray flash would generate a clear gamma-ray signal in the small particle detector.

"Our system ran for almost two years, and we saw a lot of lightning," said Bowers. But during those storms, they did not observe anything that looked like terrestrial gamma-ray flashes. "We did, however, see large count-rate bursts during clear, fair-weather days, which made us scratch our heads."

HAWC data gathered during these times showed that, in every case, the large array that comprises HAWC had been overwhelmed by extremely large cosmic-ray showers--so large that the Los Alamos researchers couldn't estimate their size.

UC Santa Cruz collaborator David Smith found that these fair-weather bursts had previously been observed by scientists in Russia, who called them "neutron bursts," and determined that they were the result of neutron production in the soil around the impact point of cosmic ray shower cores.

Previous work that simulated these events had only considered hadrons - a type of subatomic particle - in the core of the showers. In addition to hadrons and other particles, cosmic-ray shower cores also contain a lot of gamma rays.

For this work, William Blaine, also of Los Alamos, simulated large cosmic ray-showers, and included both hadrons and gamma rays. "We were able to match our observations with the simulations," said Bowers. "We found that the gamma rays produce the same type of neutron burst as the hadrons."

This study suggests that any natural phenomena that produces a beam of gamma-rays pointed towards the ground (such as downward terrestrial gamma-ray flashes), could produce a similar "neutron burst" signature. This is significant for future terrestrial gamma-ray flash observation modeling efforts.

"It tell us that you can't just model the gamma rays hitting your detector, you'll also have to consider the neutron burst that's happening nearby," said Bowers.

The HAWC Observatory comprises an array of water-filled tanks high on the flanks of the Sierra Negra volcano in Puebla, Mexico, where the thin atmosphere offers better conditions for observing gamma rays. When gamma rays strike molecules in the atmosphere they produce showers of energetic particles. When some of those particles strike the water inside the HAWC detector tanks, they produce flashes of light called Cherenkov radiation. By studying these Cherenkov flashes, researchers reconstruct the sources of the showers to learn about the particles that caused them.

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Paper: Bowers, G. S., Shao, X.?M., Blaine, W., Dingus, B., Smith, D. M., Chaffin, J., et al. (2021). Fair weather neutron bursts from photonuclear reactions by extensive air shower core interactions in the ground and implications for Terrestrial gamma?ray flash signatures. Geophysical Research Letters, 48, e2020GL090033. https://doi.org/10.1029/2020GL090033

Funding: Los Alamos Laboratory Directed Research and Development Program, U.S. National Science Foundation, U.S. Department of Energy Office of High-Energy Physics

About Los Alamos National Laboratory (http://www.lanl.gov)

Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is managed by Triad, a public service oriented, national security science organization equally owned by its three founding members: Battelle Memorial Institute (Battelle), the Texas A&M University System (TAMUS), and the Regents of the University of California (UC) for the Department of Energy's National Nuclear Security Administration.

Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.

LA-UR-21-23994

The state of China's climate in 2020: Warmer and wetter again

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

Research News

 

IMAGE: AUTOMATIC WEATHER STATION NEAR THE YANGTZE RIVER IN NANJING, WHICH FLOODED ON 23 JULY 2020 view more 

CREDIT: BING ZHOU

The National Climate Center (NCC) of China has just completed a report that gives an authoritative assessment of China's climate in 2020. It provides a summary of China's climate as well as the major weather and climate events that took place throughout the year. This is the third consecutive year that the NCC has published an annual national climate statement in Atmospheric and Oceanic Science Letters (AOSL).

"Against the background of global warming, extreme weather and climate events occur more frequently and have wide influence on society and economies. Last year, floods, droughts, typhoons, low-temperature freezing and snow disasters, and dust storms attacked China and caused severe losses," says Wei Li, Director of the Climate Services Division of the NCC.

According to the report, in 2020, China's climate was warm and wet on the whole, and disasters caused by rainstorms and flooding were more serious than those by drought. The mean air temperature in China was 0.7? above normal, and the annual rainfall was 694.8 mm, which was 10.3% above normal.

In summer, southern China experienced the most severe flooding with extreme heavy rainstorms since 1998. Drought brought slight impacts and losses in China. High temperatures occurred earlier than normal with extreme values, and lasted longer than normal in summer over the south of China. The number of landfalling typhoons was lower than normal, while three typhoons successively affected Northeast China from late August to early September, which was the first time since 1949. Cold-air processes had a wide influence and brought a substantial decrease in air temperature in local areas.

Compared with the average values of the past 10 years, the affected crop area and the numbers of deaths and missing persons in 2020 were significantly smaller, while direct economic losses were slightly larger.

Nonetheless, Li warns that the hazards of climate disasters are increasing: "The WMO announced in January 2021 that the global average air temperature in 2020 was 1.2°C ± 0.1°C above the pre-industrial level and one of the three warmest on record. China also experienced a serious heatwave in summer and the mean air temperature in China was warmer than normal. Disaster prevention and reduction remains the focus of society."

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New computer model helps brings the sun into the laboratory

DOE/PRINCETON PLASMA PHYSICS LABORATORY

Research News

 

IMAGE: PPPL PHYSICIST ANDREW ALT IN FRONT OF AN IMAGE OF THE SUN view more 

CREDIT: COMPOSITE IMAGE BY ELLE STARKMAN / SOLAR IMAGE BY NASA GODDARD MEDIA STUDIOS

Every day, the sun ejects large amounts of a hot particle soup known as plasma toward Earth where it can disrupt telecommunications satellites and damage electrical grids. Now, scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) and Princeton University's Department of Astrophysical Sciences have made a discovery that could lead to better predictions of this space weather and help safeguard sensitive infrastructure.

The discovery comes from a new computer model that predicts the behavior of the plasma in the region above the surface of the sun known as the solar corona. The model was originally inspired by a similar model that describes the behavior of the plasma that fuels fusion reactions in doughnut-shaped fusion facilities known as tokamaks.

Fusion, the power that drives the sun and stars, combines light elements in the form of plasma -- the hot, charged state of matter composed of free electrons and atomic nuclei -- that generates massive amounts of energy. Scientists are seeking to replicate fusion on Earth for a virtually inexhaustible supply of power to generate electricity.

The Princeton scientists made their findings while studying roped-together magnetic fields that loop into and out of the sun. Under certain conditions, the loops can cause hot particles to erupt from the sun's surface in enormous burps known as coronal mass ejections. Those particles can eventually hit the magnetic field surrounding Earth and cause auroras, as well as interfere with electrical and communications systems.

"We need to understand the causes of these eruptions to predict space weather," said Andrew Alt, a graduate student in the Princeton Program in Plasma Physics at PPPL and lead author of the paper reporting the results in the Astrophysical Journal.

The model relies on a new mathematical method that incorporates a novel insight that Alt and collaborators discovered into what causes the instability. The scientists found that a type of jiggling known as the "torus instability" could cause roped magnetic fields to untether from the sun's surface, triggering a flood of plasma.

The torus instability loosens some of the forces keeping the ropes tied down. Once those forces weaken, another force causes the ropes to expand and lift further off the solar surface. "Our model's ability to accurately predict the behavior of magnetic ropes indicates that our method could ultimately be used to improve space weather prediction," Alt said.

The scientists have also developed a way to more accurately translate laboratory results to conditions on the sun. Past models have relied on assumptions that made calculations easier but did not always simulate plasma precisely. The new technique relies only on raw data. "The assumptions built into previous models remove important physical effects that we want to consider," Alt said. "Without these assumptions, we can make more accurate predictions."

To conduct their research, the scientists created magnetic flux ropes inside PPPL's Magnetic Reconnection Experiment (MRX), a barrel-shaped machine designed to study the coming together and explosive breaking apart of the magnetic field lines in plasma. But flux ropes created in the lab behave differently than ropes on the sun, since, for example, the flux ropes in the lab have to be contained by a metal vessel.

The researchers made alterations to their mathematical tools to account for these differences, ensuring that results from MRX could be translated to the sun. "There are conditions on the sun that we cannot mimic in the laboratory," said PPPL physicist Hantao Ji, a Princeton University professor who advises Alt and contributed to the research. "So, we adjust our equations to account for the absence or presence of certain physical properties. We have to make sure our research compares apples to apples so our results will be accurate."

Discovery of the jiggling plasma behavior could also lead to more efficient generation of fusion-powered electricity. Magnetic reconnection and related plasma behavior occur in tokamaks as well as on the sun, so any insight into these processes could help scientists control them in the future.

Support for this research came from the DOE, the National Aeronautics and Space Administration, and the German Research Foundation. Research partners include Princeton University, Sandia National Laboratories, the University of Potsdam, the Harvard-Smithsonian Center for Astrophysics, and the Bulgarian Academy of Sciences.

PPPL, on Princeton University's Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas -- ultra-hot, charged gases -- and to developing practical solutions for the creation of fusion energy. The Laboratory is managed by the University for the U.S. Department of Energy's Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science