Highlighted papers, November 2024

Every month, the FSE Science Newsroom publishes a number of short articles on recent scientific publications from the faculty. Below you can read about the highlighted papers of last month.

Producing liquid hydrogen using environmentally friendly technology

If we want to use hydrogen as fuel for cars or airplanes, or for chemical storage of excess renewable energy, it would be most efficient if it were liquid. However, this would require cooling it down to minus 253°C or 20°K, which is very energy-consuming when using a conventional cooling technology.

A team of scientists led by Graeme Blake, assistant professor of Inorganic Chemistry at the University of Groningen (the Netherlands), has been researching a more energy-efficient cooling method called magnetocaloric cooling. This method involves using materials that will heat up when they are exposed to a magnetic field. The heat is then transferred to a ‘heat sink’, which leaves the material - and its surroundings - colder once the magnetic field is removed. The method not only consumes less energy, but also eliminates the need for refrigerant gases, which have a strong greenhouse effect.

Blake used magnetocaloric cooling to reach 20°K, cold enough to liquify hydrogen. This has been done before, but only with materials containing rare-earth metals. The mining of these metals consumes a lot of energy and can lead to environmental problems. What’s revolutionary about Blake’s material is that it does not contain these metals: ‘Our material, or a future variant of it, could probably reduce the cost and improve the environmental friendliness of this cooling technology.’

Reference: J.J.B. Levinsky, B. Beckmann, T. Gottschall, D. Koch, M. Ahmadi, O. Gutfleisch & G.R. Blake: Giant magnetocaloric effect in a rare-earth-free layered coordination polymer at liquid hydrogen temperatures, Nature Communications. November 4, 2024

Microbiologists join the battle against climate change

Micro-organisms, such as bacteria or algae, offer numerous potential solutions to mitigate the effects of climate change. They can capture and store carbon, for example in soils and oceans, or break down the potent greenhouse gas methane. Additionally, they can  produce biofuel, break down pollutants, or strengthen ecosystems.

Eighteen microbiologists, including University of Groningen Professor Joana Falcao Salles, have written an editorial outlining how microorganisms can provide solutions for problems caused by climate change. Published in 14 different journals, the article is a call to action from microbiology societies and institutions, supported by editors and publishers.

Ecological knowledge

‘The most important message of our editorial is that microorganisms can provide solutions to help us fight climate change,’ says Falcao Salles. The paper emphasizes their pivotal yet often overlooked role in climate regulation. To address this, the authors propose establishing a global, science-based climate task force, in which microbial ecologist representatives from scientific societies and institutions contribute to developing and implementing microbiological solutions grounded in ecological knowledge.

‘Writing this paper has already initiated several important conversations’, says Falcao Salles. ‘The next steps are to bring this discussion to next year’s climate conference in Brazil and to have microbial ecologists included in the IPCC committee.’

Reference: Peixoto, R., Voolstra, C.R., Stein, L.Y. et al. Microbial solutions must be deployed against climate catastrophe. Nature Microbiology (and 13 other journals), November 11, 2024

Robot flies like a bird

Have you ever wondered why an airplane has a vertical tailfin? The plane needs it to stabilize its flight. Since flying without a vertical tail is much more energy-efficient, the aviation industry has worked hard to accomplish this – so far without much success. However, birds don’t need a vertical fin, which raises the question: how do they do it? 

David Lentink, Professor of Biomimetics at the University of Groningen, has developed a robotic bird model with real pigeon feathers to show how they do it. In previous work, he found that birds continuously adjust the shape of their wings and tail. In his latest paper, he shows that his pigeon-like robot can replicate these movements.

Fuel-efficient airplanes

An algorithm controls nine servo motors which move the feathers to continuously change the shape of the wings and tail. The algorithm mimics reflexes, which are thought to be used by birds to stabilize themselves. In 1929, German scientist Franz Groebbels proposed that this enables birds to fly like ‘automatic airplanes’. Almost a century later, the robotic bird ‘PigeonBot II’ confirms his idea, as it was successfully tested in a wind tunnel, and then flown autonomously in the open air.

Apart from showing how birds manage to fly without vertical tailfins, Lentink opened the way to designing more fuel-efficient airplanes: ‘The European Airbus group created a concept, visualizing how such a plane should look. Our study provides the knowledge to realize their ideas.’ Furthermore, the new design concept reduces a plane’s radar signature, which can improve jet fighters operations.

Reference: Eric Chang, Diana D. Chin, David Lentink: Bird-inspired reflexive morphing enables rudderless flight. Science Robotics, November 20, 2024.

What came first, life or evolution?

Darwinian rules can act on non-living material

We know that Darwinian evolution acts on all forms of life, but does evolution act on non-living materials as well? In a paper published in Nature Chemistry on 29 November, Sijbren Otto, Professor of Systems Chemistry at the University of Groningen, demonstrates that key principles of Darwinian evolution, such as survival of the fittest, also manifest themselves in simple non-living systems.

Otto and his team used a system of three different self-replicating molecules, that, under the right conditions, grow and divide spontaneously. When set up to compete against each other, all requiring the same chemical building block to grow and replicate, one of them eventually outcompeted the others. This is an example of ‘survival of the fittest’. However, when they required different building blocks, all replicators were able to ‘survive’ and co-exist. This resembles how species co-exist in different ecological niches.

These results demonstrate that the basic principles of Darwinian evolution can act on non-living materials, suggesting that evolution predates life. The next step is to investigate where Darwinian evolution can lead such non-living materials. ‘This work sheds new light on how life may have emerged from non-living materials and marks an important step in the synthesis of new forms of life in the laboratory.’

Reference: Marcel J. Eleveld, Yannick Geiger, Juntian Wu, Armin Kiani, Gaël Schaeffer & Sijbren Otto: Competitive exclusion among self-replicating molecules curtails the tendency of chemistry to diversify. Nature Chemistry, November 29, 2024