Oldest army ant ever discovered reveals iconic predator once raided Europe

A rare 35-million-year-old fossil army ant, discovered in a 100-year-old museum collection, uncovers previously unknown European relatives of the infamously voracious insect

Peer-Reviewed Publication

NEW JERSEY INSTITUTE OF TECHNOLOGY

 

IMAGE: RESEARCHERS AT NEW JERSEY INSTITUTE OF TECHNOLOGY AND COLORADO STATE UNIVERSITY HAVE REPORTED THE DISCOVERY OF THE OLDEST ARMY ANT ON RECORD, PRESERVED IN BALTIC AMBER DATING TO THE EOCENE (~35 MILLION YEARS AGO). view more 

CREDIT: SOSIAK ET AL. 2022, MUSEUM OF COMPARATIVE ZOOLOGY, HARVARD UNIVERSITY; ©PRESIDENT AND FELLOWS OF HARVARD COLLEGE

Their nomadic lifestyle and ravenous raiding have taken army ants (Dorylinae) to most continents on Earth, but a rare fossil discovery is now offering first evidence that the infamous predators once swarmed a land they are strikingly absent from today — Europe.

In the journal Biology Letters, researchers at New Jersey Institute of Technology and Colorado State University have reported the discovery of the oldest army ant on record, preserved in Baltic amber dating to the Eocene (~35 million years ago).

The eyeless specimen Dissimulodorylus perseus (D. perseus) — named after the mythical Greek hero Perseus who famously defeated Medusa with the limited use of sight — marks just the second fossil army ant species ever described, and the first army ant fossil recovered from the Eastern Hemisphere.

Sized at roughly 3 millimeters in length, researchers say the ant fossil brings to light previously unknown army ant lineages that would have existed across Continental Europe before undergoing extinction in the past 50 million years.

Remarkably, the fossil had been kept in obscurity for nearly 100 years in the Museum of Comparative Zoology at Harvard University, before being identified by the paper’s lead author and NJIT Ph.D. candidate, Christine Sosiak.

“The museum houses hundreds of drawers full of insect fossils, but I happened to come across a tiny specimen labeled as a common type of ant while gathering data for another project,” said Sosiak. “Once I put the ant under the microscope, I immediately realized the label was inaccurate … I thought, this is something really different.”

“This amber would have been excavated around or before the 1930s, so to now learn it contained a rare army ant is surprising enough, much less one that demonstrates these ants roamed Europe,” said Phillip Barden, assistant professor of biology at NJIT and senior author of the paper. “From everything we know about army ants living today, there’s no hint of such extinct diversity. … With this fossil now out of obscurity, we’ve gained a rare paleontological porthole into the history of these unique predators.”

A Paleontological Porthole into a Unique Predator’s History

Today, there are about 270 army ant species living in the Eastern Hemisphere, and roughly 150 across North and South America.

Based on X-ray and CT-scan analysis of the fossil, the NJIT team gathered phylogenetic and morphological data that places D. perseus as a close relative to eyeless species of army ants currently found in Africa and Southern Asia, called Dorylus.

“At the time the fossil formed, Europe was hotter and wetter than it is today and may have provided an ideal habitat for ancient army ants,” said Barden. “Europe underwent several cooling cycles over tens of millions of years since the Eocene, however, which may have been inhospitable to these tropical-adapted species.”

The team’s analysis further revealed that the ant possessed an enlarged antibiotic gland, typically found in other army ants for sustaining life underground, suggesting the long-lost European army ant lineage was similarly suited to subterranean living.

It’s a factor Sosiak says makes this fossil, and other fossil army ants, a rarity. Only one definitive fossil had been recorded until now, unearthed from the Caribbean (16 ~Ma.).

“This was an incredibly lucky find. Because this ant was probably subterranean like most army ants today, it was much less likely to come into contact with tree resin that forms such fossils,” said Sosiak. “We have a very small window into the history of life on our planet, and unusual fossils such as this provide fresh insight.”

Sosiak says D. perseus’ anatomical traits — including its sharply pointed mandibles and lack of eyes — help classify the specimen as a worker ant in its colony, which would have been involved in carrying its queen’s larvae and raiding for food with soldier ants when it was alive.

“Army ant workers participate in raiding swarms, hunting other insects and even vertebrates. Because these army ants are blind, they use chemical communication to stay coordinated with one another to take down large prey,” explained Sosiak. “This worker may have strayed too far from its fellow hunters and into sticky tree resin, which eventually solidified and encased the ant as we see it today.”

Army ants’ distinct combination of behavior and traits is so unusual in the ant world, that it’s warranted its own name — army ant syndrome.

In contrast with other ant lineages, army ants have wingless queens capable of laying millions of eggs a day, while their nomadic colonies temporarily occupy nests between phases of travel that take the shape of bivouacs, sometimes involving millions of ants stretching for 100m.

The carnivores are perhaps best known for their highly coordinated foraging that can involve consuming upwards of 500,000 prey a day.

Barden says army ant syndrome is a case of convergent evolution that would have occurred twice — once in the Neotropics and once in the Afrotropics.

“The discovery is the first physical evidence of the army ant syndrome in the Eocene, establishing that hallmarks of these specialized predators were in place even before the ancestors of certain army ants like Dorylus,” said Barden.

For now, the newly identified fossil joins just eight fossil species within the ant subfamily that army ants belong to, called Dorylinae — five from Dominican amber (16 ~Ma.), and three species known from Baltic amber (34 ~Ma.).

D. perseus will remain deposited at the Museum of Comparative Zoology at Harvard University for future study.

Reconstruction of D. perseus from NJIT’s Barden Lab shows anatomical similarities with certain army ants alive today.

CREDIT

Museum of Comparative Zoology, Harvard University; ©President and Fellows of Harvard College

Sosiak CE, Borowiec ML, Barden P. 2022 An Eocene army ant. Biol. Lett.

https://doi.org/10.1098/rsbl.2022.0398

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JOURNAL

Biology Letters

DOI

10.1098/rsbl.2022.0398 

NTU Singapore scientists convert waste paper into battery parts for smartphones and electric vehicles

Peer-Reviewed Publication

NANYANG TECHNOLOGICAL UNIVERSITY

 

IMAGE: ASSISTANT PROFESSOR LAI CHANGQUAN, FROM NTU’S SCHOOL OF MECHANICAL & AEROSPACE ENGINEERING, THE LEAD SCIENTIST THAT DEVELOPED THE TECHNIQUE TO CREATE ANODES FROM WASTE PAPER. view more 

CREDIT: NTU SINGAPORE

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a technique to convert waste paper, from single-use packaging and bags, and cardboard boxes, into a crucial component of lithium-ion batteries.

 

Through a process called carbonisation which converts paper into pure carbon, the NTU researchers turned the paper’s fibres into electrodes, which can be made into rechargeable batteries that power mobile phones, medical equipment, and electric vehicles.

 

To carbonise the paper, the team exposed the paper to high temperatures, which reduces it to pure carbon, water vapour and oils that can be used for biofuel. As carbonisation takes place in the absence of oxygen, this emits negligible amounts of carbon dioxide, and the process is a greener alternative to disposing of kraft paper through incineration, producing large amounts of greenhouse gasses.

 

The carbon anodes produced by the research team also demonstrated superior durability, flexibility, and electrochemical properties. Laboratory tests showed that the anodes could be charged and discharged up to 1,200 times, which is at least twice as durable as anodes in current phone batteries. The batteries that use the NTU-made anodes could also withstand more physical stress than their counterparts, absorbing crushing energy up to five times better.

 

The NTU-developed method also uses less energy-intensive processes and heavy metals compared to current industrial methods of manufacturing battery anodes. As the anode is worth 10 per cent to 15 per cent of the total cost of a lithium-ion battery[1], this latest method, which uses a low-cost waste material, is expected to also bring down the cost of manufacturing them.

 

The findings were published in the scientific peer-reviewed journal Additive Manufacturing in October.

Using waste paper as the raw material to produce battery anodes would also ease our reliance on conventional sources for carbon, such as carbonaceous fillers and carbon-yielding binders, which are mined and later processed with harsh chemicals and machinery.

 

Paper waste, which comprises disposed paper bags cardboard, newspaper, and other paper packaging, accounted for nearly a fifth of the waste generated in Singapore in 2020[2].

 

Kraft paper bags, which make up the bulk of Singapore’s paper waste, were also found to have large environmental footprints compared to their counterparts made of cotton and plastic, due to their greater contribution to global warming when incinerated and the eco-toxicity potential in producing them, a separate 2020 NTU study[3] found.

 

The current innovation which presents an opportunity to upcycle waste products and reduce our dependence on fossil fuels, accelerating our transition towards a circular economy, green materials, and clean energy, reflects NTU's commitment to mitigate our impact on the environment, which is one of four humanity’s grand challenges that the University seeks to address through its NTU 2025 strategic plan.

 

Assistant Professor Lai Changquan, from NTU’s School of Mechanical & Aerospace Engineering, who led the project, said: “Paper is used in many facets in our daily lives, from gift wrapping and arts and crafts, to a myriad of industrial uses, such as heavy-duty packaging, protective wrapping, and the filling of voids in construction. However, little is done to manage it when it is disposed of, besides incineration, which generates high levels of carbon emissions due to their composition. Our method to give kraft paper another lease of life, funnelling it into the growing need for devices such as electric vehicles and smartphones, would not only help cut down on carbon emissions but would also ease the reliance on mining and heavy industrial methods.”

 

The research team has filed for a patent with NTUitive, NTU’s innovation and enterprise company. They are also working towards commercialising their invention.

The recipe for greener battery parts

To produce the carbon anodes, the NTU researchers joined and laser cut several thin sheets of kraft paper to form different lattice geometries, some resembling a spikey piñata (see Figure 1). The paper was then heated to 1200°C in a furnace without the presence of oxygen, to convert it into carbon, forming the anodes.

The NTU team attributes the anode’s superior durability, flexibility, and electrochemical properties to the arrangement of the paper fibres. They said the combination of strength and mechanical toughness shown by the NTU-made anodes would allow batteries of phones, laptops and automobiles to better withstand shocks from falls and crashes.

 

Current lithium battery technology relies on internal carbon electrodes that gradually crack and crumble after physical shocks from being dropped, which is one of the main reasons why battery life gets shorter with time.

 

The researchers say that their anodes, which are hardier than current electrodes used in batteries, would help address this problem and extend the life of batteries in a wide array of uses, from electronics to electric vehicles.

 

Co-author of the study Mr Lim Guo Yao, a research engineer from NTU’s School of Mechanical & Aerospace Engineering, said: “Our anodes displayed a combination of strengths, such as durability, shock absorption, electrical conductivity, which are not found in current materials. These structural and functional properties demonstrate that our kraft paper-based anodes are a sustainable and scalable alternative to current carbon materials, and would find economic value in demanding, high-end, multifunctional applications, such as the nascent field of structural batteries.”

 

Asst Prof Lai added: “Our method converts a common and ubiquitous material – paper – into another that is extremely durable and in high demand. We hope that our anodes will serve the world’s quickly growing need for a sustainable and greener material for batteries, whose manufacturing and improper waste management have shown to have a negative impact on our environment.”

 

Highlighting the significance of the work done by the NTU research team, Professor Juan Hinestroza from the Department of Human Centered Design of Cornell University, US, who was not involved in the research, said: “As kraft paper is produced in very large quantities and disposed likewise all over the world, I believe that the creative approach pioneered by the researchers at NTU Singapore has a great potential for impact at a global scale. Any discovery that will allow the use of waste as a raw material for high-value products like electrodes and foams is indeed a great contribution. I think that this work may open a new avenue and motivate other researchers to find pathways for the transformation of other cellulose-based substrates, such as textiles and packaging materials, which are being discarded in large quantities all over the globe.”

 

The NTU team will be conducting further research to improve the energy storage capacity of their material and minimise the heat energy required to convert the paper into carbon.

 

###

 

Figure 1: Illustration of the process to convert kraft paper into anodes, developed by NTU Singapore. The structures were turned into carbon anodes at high temperatures in a subsequent step.

 

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[1] Lux Research. Li-ion Battery Innovation Roadmap (2019).

[2] Singapore National Environmental Agency. Reduction In Overall Waste Generation In 2020, With Less Waste Sent To Semakau Landfill (2021).

[3] Nanyang Technological University. NTU Singapore scientists report that plastic bags could be 'ecofriendlier' than paper and cotton bags in cities like Singapore (2020).

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JOURNAL

Additive Manufacturing

DOI

10.1016/j.addma.2022.102992 

METHOD OF RESEARCH

Experimental study

ARTICLE TITLE

Exceptional energy absorption characteristics and compressive resilience of functional carbon foams scalably and sustainably derived from additively manufactured kraft paper

Biovac signs deal with IVI to develop and manufacture oral cholera vaccine for African and global markets

Business Announcement

INTERNATIONAL VACCINE INSTITUTE

South African based Bio-pharmaceutical company, Biovac, has concluded a ground-breaking licensing and technology transfer agreement with the International Vaccine Institute (IVI), a non-profit international organisation headquartered in South Korea, for the manufacture of an oral cholera vaccine (OCV).

 

The project is significant for Biovac as it enables drug substance manufacturing capability to be built, that is, production of the antigen/raw material needed to manufacture actual vaccines. This is one of the remaining steps in the vaccine manufacturing value chain that is currently missing not only at Biovac but across the African vaccine manufacturing landscape.

 

The agreement comes at a time as cholera outbreaks – prompted by climate change, armed conflict and displacements – wreak havoc on fragile health systems, as observed in Pakistan, Nigeria and Malawi as recent examples. This places additional demand on already-limited supply of cholera vaccines globally.[1] The extent of cholera outbreaks in recent years has escalated while there has been an increasing gap between supply and demand for cholera vaccines.

 

The partnership with IVI aims to license and transfer technology with the ultimate aim of increasing production volumes in order to reduce the critical shortage of vaccines needed to prevent cholera globally. This transfer of technology[2] will also establish and demonstrate capacity for Good Manufacturing Process (GMP) scale-up, local manufacture of clinical trial product, and end-to-end production of vaccines in Africa for African and worldwide usage. After many decades, this will be a critical step forward for vaccine production on the continent.

 

This is in a market (Africa) where less than 1% of vaccines are locally manufactured and where infectious diseases are still the leading cause of death, especially in children under five years.[3]

 

Notably, African leaders have committed to creating an indigenous vaccine industry, with the goal of boosting the share of vaccines manufactured in Africa from 1% in 2021 to 60% in 2040.[4]

 

The agreement is underpinned by collective support of R120 million ($6.9 million) from Wellcome and the Bill & Melinda Gates Foundation for the first phase of the project. It will allow Biovac to expand its capabilities from filling and packaging of vaccine vials to end-to-end vaccine product development and drug substance manufacture.

 

Biovac CEO, Dr Morena Makhoana, says the COVID-19 pandemic exposed Africa’s lack of local production capacity. “It became clear that increasing self-sufficiency is important if Africa is to have better control over its own public health and vaccine supply chains.” He says for African vaccine manufacture to be sustainable, the continent needs to ensure that R&D, technology transfers, scale up, drug substance manufacture and licensing all take place on African soil, alongside already established fill-finish manufacturing activities.

 

“This initiative will be the beginning of end-to-end vaccine manufacture at Biovac, while at the same time addressing an ongoing and increasing cholera disease burden globally. In addition, this feeds directly into Biovac’s facilities expansion plan to scale up production capacity and will most likely be the first product (drug substance and drug product) to be manufactured in our new facility when it comes on line.”

 

The technology transfer process will commence in January 2023, with the first clinical trial batches expected to be produced in 2024 and licensing of the product by the South African National Regulatory Authority (SAHPRA) to be concluded in 2026 alongside WHO Prequalification certification which will follow shortly thereafter

 

Makhoana highlights the importance of achieving pre-qualification from the World Health Organization (WHO). “Through this and other projects, Biovac plans to attain WHO pre-qualification. We will then be well placed to supply UN agencies such as WHO and UNICEF/GAVI as many African countries and other least developed countries source their vaccines through this mechanism.

 

Director of IVI’s Cholera Program, Dr Julia Lynch, says IVI’s technical know-how and required materials to produce OCV have been transferred to four different manufacturers to date.

 

“OCV is a proven, highly effective preventive measure against a disease that strikes the most vulnerable. Enthusiastic uptake of the vaccine by countries has resulted in a demand that exceeds current supply, and the supply shortage has been made worse amid an increasing number of cholera outbreaks in 2022.

 

“We are thrilled to partner with Biovac to complete a technology transfer of OCV that will add another manufacturer to the marketplace and expand production capacity. With Biovac and the support of the Gates Foundation and Wellcome, we aim to expand the global supply of OCV and prevent cholera worldwide.”

 

IVI Director-General, Jerome Kim, concurs with Lynch and says maintaining a global supply of the cholera vaccine is critical for preventing cholera and controlling outbreaks. “In the face of a supply shortage, IVI’s collaboration with Biovac to complete the transfer of OCV technology will make a significant impact on our ability to protect communities at highest risk of this deadly, although vaccine-preventable, disease.”

 

President of the Bill & Melinda Gates Foundation’s Global Health Program, Trevor Mundel, says the foundation is excited to support this important project to increase access to lifesaving oral cholera vaccines.

 

“Unfortunately, we are seeing now more than ever that it will be essential to have a robust and diverse supply of the vaccine to prevent death and disability from this persistent scourge. We see this type of tech transfer to manufacturing partners as a key way to ensure a strong supply of high-quality, affordable vaccines.”

 

Professor Gordon Dougan, Director of Infectious Diseases at Wellcome Trust, says the tools needed to control cholera exist – a combination of good epidemiology, water management and vaccines – but now we urgently need to increase access to an affordable, effective vaccine to meet the growing demand. 

 

“We are proud to be funding this project to build capacity to manufacture this much-needed vaccine and generate a sustainable vaccine supply within the countries that need them most. For the first time in recent history, an affordable life-saving oral cholera vaccine will be made on the African continent, for the African people,” concludes Dougan.

 

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[1] https://www.nytimes.com/2022/10/31/health/cholera-outbreaks-vaccine.html?searchResultPosition=1

[2] https://www.twi-global.com/technical-knowledge/faqs/what-is-technology-transfer

[3] https://www.who.int/news-room/fact-sheets/detail/levels-and-trends-in-child-under-5-mortality-in-2020

[4] https://www.nature.com/articles/d41586-021-01048-1

Democracy after COVID-19: Pandemic fatigue fueled political mistrust and conspiracy beliefs across Europe and the United States

In a new study, researchers find a significant societal impact of the pandemic beyond the domain of health and raise concerns about the ability of democratic societies to cope with future crises such as the climate crisis

Peer-Reviewed Publication

AARHUS UNIVERSIty

 

IMAGE: PROFESSOR MICHAEL BANG PETERSEN, AARHUS UNIVERSITY. PHOTO: IDA MARIE JENSEN, AARHUS UNIVERSITY view more 

CREDIT: PHOTO: IDA MARIE JENSEN, AARHUS UNIVERSITY

Many of us found it hard to keep up with official restrictions as the COVID-19 pandemic dragged on. We experienced  pandemic fatigue. And this fatigue led to wide-spread political discontent in Western democracies, according to a new study from Aarhus University, which has now been published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).

“Prior research has found that small groups of people have been radicalised and that pandemic fatigue has proven a health challenge, but our new study shows that we are facing challenges far beyond the domain of health or the radicalisation of some groups,” says Michael Bang Petersen, professor of political science at Aarhus University and one of the researchers behind the study.

For instance, broad segments of the public respond that they support protests against the government’s policies, that they are concerned about their own democratic rights or that they believe the government is hiding important information from the public about the coronavirus.  

Such political discontent is closely linked with the feeling of pandemic fatigue, according to the study.

“Based on our research method, we can be quite confident that there is not just a correlation between pandemic fatigue and political discontent. Rather, fatigue is a direct cause of political discontent,” says Frederik Jørgensen, assistant professor of political science at Aarhus University and the lead author of the study.

Political and academic debate on ‘fatigue’
During the pandemic, both researchers and authorities have discussed the concept of pandemic fatigue and whether it exists in populations. For one thing, the British government was met with criticism for delaying their lockdown during the first wave of the pandemic based on the exact argument that restrictions could generate fatigue.

“Our results are important in this debate, because they demonstrate that citizens do experience fatigue during this type of crisis, in which the government imposes strict but often necessary measures on its citizens. And it turns out that loneliness during the pandemic in particular served to induce fatigue,” says Frederik Jørgensen.

Authorities may prevent fatigue
The researchers have collected 13 rounds of data in Denmark, the United Kingdom, Germany, France, Italy, Hungary, Sweden and the United States. The surveys were fielded on a regular basis in 2020 and 2021, while the epidemic curves and restrictions in each country increased and decreased at different paces, some countries more burdened by the COVID-19 pandemic than others. But there is a clear pattern across national borders: Fatigue increases as time goes by, when the stringency of restrictions goes up and when death numbers go down.

According to the researchers, the latter is significant in terms of adopting suitable policies. When death counts are high, citizens report lower levels of fatigue.

“Citizens are able to keep up with restrictions when these are necessary. This means there may be a sound basis for tightening and loosening restrictions as needed, instead of keeping them at a constant level as Germany and other countries did. By tightening and loosening restrictions, the authorities appear to be able to minimise pandemic fatigue and prevent it from sticking – and thus prevent political discontent from increasing even further,” says professor Michael Bang Petersen, who is head of the research project on the pandemic that this study is part of.

More crises, more fatigue and more political discontent
The head of the research project notes that several Western democracies were strained by polarisation and destabilisation even before the COVID-19 pandemic. He also notes that the world is facing a series of other crises which could add fuel to the fire. For instance the climate crisis and the current energy crisis.

"Citizens may feel fatigued and direct their frustrations towards the authorities in these crises as well. Fatigue during a crisis is something that the authorities should take very seriously and take active steps to avoid. One such step could be open communication that explains why action is necessary,” says professor of political science at Aarhus University Michael Bang Petersen.

  ____

Facts
We strive to comply with Universities Denmark’s principles for good research communication. For this reason, we provide the following information as a supplement to this article: 

Type of study:
Longitudinal and panel surveys collected in the United States, the United Kingdom, Germany, France, Italy, Hungary, Sweden and Denmark.

External collaborators:
None.

External funding:
The study is part of the research project How Democracies Cope with COVID-19: A Data-Driven Approach (HOPE), which is funded by the Carlsberg Foundation.

Conflict of interest:
None.

Link to the scientific article:
www.pnas.org/doi/10.1073/pnas.2201266119

 

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2201266119 

ARTICLE TITLE

Pandemic fatigue fueled political discontent during the COVID-19 pandemic

Study examines racial disparities in older patients hospitalized for heart attacks

Peer-Reviewed Publication

WILEY

In an analysis in the Journal of the American Geriatrics Society that included data on 2,918 patients aged 75 years or older who were hospitalized for heart attacks at 94 US hospitals from 2013–2016, Black participants were more likely than white participants to have impairments in cognition (37.6% versus 14.5%), mobility (66.0% versus 54.6%) and vision (50.1% versus 35.7%) at the time of admission to the hospital. 

Black participants were also more likely to report a disability in one or more activities of daily living (22.4% versus 13.0%) and an unintentional loss of more than 10 lbs in the year prior to hospitalization (37.2% versus 13.0%). 

Black participants had 2-fold higher odds of dying within 6 months, but this elevated risk was no longer significant after adjusting for age, clinical characteristics, and functional/geriatric conditions.

“Functional impairments are powerful predictors of post–heart attack mortality among older adults. These impairments disproportionately affect Black patients who have traditionally been underserved by home health care services,” said corresponding author Patrick C. Demkowicz, BS, of the Yale University School of Medicine. “Our work highlights a pressing need for health systems to routinely screen for functional impairments and to ensure access to home health care services for all patients with such impairments.”

URL upon publication: https://onlinelibrary.wiley.com/doi/10.1111/jgs.18084

 

Additional Information

NOTE: The information contained in this release is protected by copyright. Please include journal attribution in all coverage. For more information or to obtain a PDF of any study, please contact: Sara Henning-Stout, newsroom@wiley.com.

About the Journal

Journal of the American Geriatrics Society (JAGS) is the go-to journal for clinical aging research. We provide a diverse, interprofessional community of healthcare professionals with the latest insights on geriatrics education, clinical practice, and public policy—all supporting the high-quality, person-centered care essential to our well-being as we age. 

About Wiley

Wiley is one of the world’s largest publishers and a global leader in scientific research and career-connected education. Founded in 1807, Wiley enables discovery, powers education, and shapes workforces. Through its industry-leading content, digital platforms, and knowledge networks, the company delivers on its timeless mission to unlock human potential. Visit us at Wiley.com. Follow us on Facebook, Twitter, LinkedIn and Instagram.

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JOURNAL

Journal of the American Geriatrics Society

DOI

10.1111/jgs.18084 

ARTICLE TITLE

Racial disparities among older adults with acute myocardial infarction: The SILVER-AMI study

ARTICLE PUBLICATION DATE

23-Nov-2022

A nanoscale view of bubble formation

A new model now describes the boiling process with much greater precision

Peer-Reviewed Publication

HELMHOLTZ-ZENTRUM DRESDEN-ROSSENDORF

 

IMAGE: A VERY THIN FILM OF LIQUID FORMS UNDER A STEAM BUBBLE DURING BOILING. IT DETERMINES HOW PRECISELY THE BUBBLES GROW AND DETACH FROM DIFFERENT SURFACES. A GERMAN-CHINESE RESEARCH TEAM LED BY THE HZDR OBSERVED THESE PROCESSES ON THE NANOMETER SCALE FOR THE FIRST TIME. view more 

CREDIT: HZDR/BLAUROCK

When a liquid boils in a vessel, tiny vapor bubbles form at the bottom and rise, transferring heat in the process. How these small bubbles grow and eventually detach was previously not known in any great detail. A German-Chinese research team under the leadership of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has now managed to fundamentally expand this understanding.

Using computer simulation, the experts succeeded in modeling the behavior of molecules at the liquid–gas interface at the nanometer scale, enabling them to describe the boiling process with extreme precision. The findings could be applied to future cooling systems for microprocessors, or to the production of carbon-neutral hydrogen, known as green hydrogen, as the team reported in the Journal of Colloid and Interface Science (DOI: 10.1016/j.jcis.2022.10.062).

How droplets or vapor bubbles wet a surface depends on the type and nature of the surface material. For example, spherical drops form on hydrophobic materials, with minimum contact area to the base. With hydrophilic materials, however, the liquid tends to create flat deposits – the solid-liquid interface is then much larger. Such processes can be described theoretically by the Young–Laplace equation. This equation yields a contact angle that characterizes droplet behavior on the surface: large angles indicate poor wetting, whereas small angles indicate good wetting.

When a vapor bubble forms on a wall in a boiling liquid, a very thin film of liquid – invisible to the eye – remains beneath it. This film determines how the bubble grows and how it detaches from the wall. The contact angle also plays a key role in this respect.

The underlying theory is based on a relatively simple approach. “It takes into account both the pressure exerted externally by the liquid and the vapor pressure inside the bubble,” explained Professor Uwe Hampel, Head of Experimental Thermal Fluid Dynamics at the HZDR. “Then there is capillary pressure, which is created by the curvature of the bubble surface.”

Recently, however, a range of experiments using laser measurement have demonstrated that this established theory fails for very small droplets and bubbles: on the nanoscale, the measured contact angles deviated significantly in some cases from the theoretical predictions.

A complex interaction of molecules

To solve this problem, the German-Chinese research team set about revising the theory. To do this, they took a closer look at the processes that occur when a liquid boils. “We considered in detail the interfacial behavior of molecules,” explained HZDR researcher Dr. Wei Ding. “Then we used a computer to simulate the interaction between these molecules.”

In doing so, the research group discovered a significant difference from previous approaches: the forces acting between the molecules do not simply add up linearly. Instead, the interaction is much more complex, resulting in distinct nonlinear effects. These are precisely the effects that the experts consider in their new, expanded theory.

“Our hypothesis provides a good explanation for the results obtained in recent experiments,” stated Ding with delight. “We now have a far more precise understanding of the behavior of tiny droplets and vapor bubbles.”

Besides completing our understanding of the theoretical basis, the findings also hold the promise of progress in several areas of technology, such as microelectronics. In this area, processors are now so powerful that they give off increasing amounts of heat, which must then be dissipated by cooling systems.

“There are ideas to remove this heat by boiling a liquid,” remarked Uwe Hampel. “With our new theory, we should be able to determine the conditions under which rising vapor bubbles can dissipate heat energy most efficiently.” The equations could also help to cool fuel elements in a nuclear reactor more effectively than in the past.

More efficient hydrogen production

The electrolysis of water to produce carbon-neutral hydrogen, referred to as green hydrogen, is another potential application. Countless gas bubbles form on the membrane surfaces of an electrolyzer during water splitting. With this new theory, it seems conceivable that these bubbles can be influenced more specifically than before, enabling more efficient electrolysis in the future. The key to all these potential applications lies in the selection and structuring of appropriate materials.

“Adding nanogrooves to a surface, for example, can significantly accelerate the detachment of gas bubbles during boiling,” explained Wei Ding. “With our new theory, such structuring can now be more finely tailored – a project on which we are already working.”

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JOURNAL

Journal of Colloid and Interface Science

DOI

10.1016/j.jcis.2022.10.06 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Microscopic liquid–gas interface effect on liquid wetting

Egyptian lagoon vital to Cyprus turtles

Peer-Reviewed Publication

UNIVERSITY OF EXETER

 

IMAGE: AN ADULT GREEN TURTLE FROM KARPAZ NESTING BEACH view more 

CREDIT: FINLAY PITT

The number of green turtles breeding in Cyprus has risen in recent years – but this bounce-back depends heavily on an Egyptian lagoon where many turtles feed, new research shows.

Green turtles, an endangered species, spend most of their lives foraging in a single area, but they return to the beach where they hatched to lay eggs.

The new study, by the University of Exeter and the North Cyprus Society for the Protection of Turtles (SPOT), tagged and tracked females laying eggs at key rookeries (breeding beaches) in Cyprus, and found 74% forage at Lake Bardawil in Egypt.

The study found that nest numbers have almost tripled since the early 1990s – but the dependence on a few feeding sites, especially Lake Bardawil, leaves turtle populations vulnerable if conditions there change.

“Since about 2010, our tracking of turtles from Cyprus has shown a large increase in the number foraging at Lake Bardawil,” said Dr Robin Snape, of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

“At the same time, the number of adult turtles foraging around Cyprus and Turkey has declined – possibly due to high bycatch (accidental catch) of turtles in fisheries there.

“The overall increase in nest numbers appears to be driven by protection of nesting sites in Cyprus and conditions at Lake Bardawil.

“It’s possible that the lake will reach its capacity, and at that point the green turtle population could stop increasing.”

Lake Bardawil is a lagoon with a man-made opening that connects to the sea, allowing marine life including turtles to swim in and out.  

It was created in the 1950s as a fishery, but it has become an ideal seagrass habitat for adult green turtles, which are typically over a metre in length and weigh more than 100kg.

The new study used long-term satellite tagging to track 19 female turtles nesting at major rookeries on the Karpaz Peninsula, Cyprus.

While most of the turtles went to Lake Bardawil, one migrated 1,500 miles (2,400km) to Djerba island, Tunisia – the longest distance yet recorded for a Mediterranean green turtle.

Comparing the oldest available three-year nest count averages (1993–1995) with nest counts undertaken as part of this study (2017–2019), average annual nest numbers increased from 186 to 554.

“Given the importance of Lake Bardawil for green turtles in the Eastern Mediterranean, it’s vital that the habitat there is managed in a way that protects turtles and supports the livelihoods of fishers,” said Professor Annette Broderick, from the University of Exeter.

“Reducing bycatch and protecting habitats in other locations could also increase green turtle numbers and reduce reliance on this single location.”

The study was funded by the MAVA Foundation and the Natural Environment Research Council.

The paper, published in the journal Global Ecology and Conservation, is entitled: “Mediterranean green turtle population recovery increasingly depends on Lake Bardawil, Egypt.”

The tracks of turtles involved in the study can be viewed at SPOT’s website here.

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JOURNAL

Global Ecology and Conservation

DOI

10.1016/j.gecco.2022.e02336 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Mediterranean green turtle population recovery increasingly depends on Lake Bardawil, Egypt

New study on morphine treatment in people with COPD and severe, long term breathlessness

Peer-Reviewed Publication

LUND UNIVERSITY                        

Sometimes healthcare professionals treat patients with opioids such as morphine to relieve symptoms, but there has been a lack of evidence as to whether this helps with severe chronic breathlessness. A randomised Phase 3 study conducted by Swedish and Australian researchers now finds that morphine does not reduce worst breathlessness.

The study is published in JAMA. 

Long term shortness of breath is a common cause of ongoing suffering that often occurs with advanced serious illness and at the end of life. COPD can cause breathlessness by damaging the lungs and airways and for seriously ill people with severe long term breathlessness, physical activity is often a challenge. 

"Many people live with shortness of breath. It is distressing that no better treatment exists, but based on the results we’ve seen, we cannot generally recommend giving morphine to people with chronic breathlessness", says Magnus Ekström, a researcher in Palliative Medicine and Pulmonary Medicine at Lund University in Sweden and Chief Physician in Pulmonary Medicine at Blekinge Hospital.

The researchers included 156 patients, each for three weeks, with chronic obstructive pulmonary disease (COPD) who suffered from severe long term breathlessness. In the first week, the participants were randomised into three groups, two to regular low doses of once daily morphine (8 milligrams daily or 16 milligrams daily), and a third control group that received a placebo. 

During the subsequent two weeks, participants were randomized to receive either an additional 8 milligrams of morphine or placebo, in addition to the previous treatment. This was done to investigate the efficacy of the treatment and the risk of side effects resulting from an increased dose of morphine. The treatment was ‘double-blind’, which means the participants and those who treated them didn’t know what treatment each group was receiving. 

"Given the prevalence of long term breathlessness across the world, it is crucial that we find ways that safely and predictably reduce the suffering that this causes people, often for years", says David Currow, a palliative medicine physician at the University of Wollongong in Australia whose team worked on the study as a part of a national program to improve symptom control of people with advanced, life-limiting illnesses. 

The researchers then compared the groups to see how they rated their experience of shortness of breath. With the help of motion sensors, the researchers also measured the participants’ physical activity during the study.

"Some probably expected that the study would show that regular, low dose morphine may allow people to be more physically active. Unfortunately, across all participants, we did not see this. We didn’t see any improvements in terms of the worst breathlessness that participants experienced", says Magnus Ekström.  

According to Ekström, the use of regular low dose morphine for severe long term breathlessness should not be widely used in healthcare as a treatment for groups that experience chronic, activity-limiting shortness of breath.

"However, the study should not be interpreted as that morphine does not provide any relief to patients with severe shortness of breath at rest, or in palliative care at the end of life. We didn’t investigate that in the study. In most cases, our patients did not have shortness of breath at rest. Clinical experience shows that at the end of life and in crisis situations, morphine treatment can help", says Magnus Ekström. 

The next step will be to investigate in greater detail whether certain groups respond better to morphine, as well as which ones are at a higher risk of experiencing side effects.

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JOURNAL

JAMA

DOI

10.1001/jama.2022.20206 

ARTICLE TITLE

Effect of Regular, Low-Dose, Extended-release Morphine on Chronic Breathlessness in Chronic Obstructive Pulmonary Disease