Goethe University research team investigates aerosal formation from iodine-containing vapours in international CLOUD project
When sea ice melts and the water surface increases, more iodine-containing vapours rise from the sea. Scientists from the international research network CLOUD have now discovered that aerosol particles form rapidly from such iodine vapours, which can serve as condensation nuclei for cloud formation. The CLOUD researchers, among them atmospheric scientists from the Goethe University Frankfurt, fear a mutual intensification of sea ice melt and cloud formation, which could accelerate the warming of the Arctic and Antarctic.
FRANKFURT. More than two thirds of the earth is covered by clouds. Depending on whether they float high or low, how large their water and ice content is, how thick they are or over which region of the Earth they form, it gets warmer or cooler underneath them. Due to human influence, there are most likely more cooling effects from clouds today than in pre-industrial times, but how clouds contribute to climate change is not yet well understood. Researchers currently believe that low clouds over the Arctic and Antarctic, for example, contribute to the warming of these regions by blocking the direct radiation of long-wave heat from the Earth's surface.
All clouds are formed by aerosols, suspended particles in the air, to which water vapour attaches. Such suspended particles or aerosols naturally consist of dusts, salt crystals or molecules released by plants. Human activities cause above all soot particles to be released into the atmosphere, but also sulphuric acid and ammonia molecules, which can cluster and form new aerosol particles in the atmosphere. Model calculations show that more than half of the cloud droplets are formed from aerosol particles that have formed in the atmosphere. For the formation of clouds, it is not decisive what the aerosol particles are made of; what matters most is their size: Aerosol particles only become condensation nuclei for cloud droplets from a diameter of about 70 nanometres and up.
In the atmosphere over the sea, aerosols released by humans play a much smaller role in the formation of low clouds than over land. Besides salt crystals originating from sea spray, aerosol particles over the sea mainly originate from certain sulphur compounds (dimethyl sufide) that are released from phytoplankton and react to form sulphuric acid, for example. At least, that is what previous research concluded.
Scientists from the CLOUD consortium have now studied the formation of aerosol particles from iodine-containing vapours. The slightly pungent smell of iodine is part of the aroma of the sea air you breathe when walking along the North Sea. Every litre of seawater contains 0.05 milligrams of iodine, and when it enters the atmosphere, iodic acid or iodous acid is formed through sunlight and ozone. The scientists simulated atmospheric conditions in mid-latitudes and arctic regions in the CLOUD experimental chamber at the CERN particle accelerator centre in Geneva, including cosmic rays simulated by an elementary particle beam.
Their findings: aerosol particle formation by iodic acid takes place very rapidly, much more rapidly than the particle formation of sulphuric acid and ammonia under comparable conditions. Ions produced by cosmic rays further promote particle formation. For the transformation of the molecular iodine into the iodine-containing acids, not even UV radiation and only a little daylight are necessary. In this way, very large aerosol quantities can be formed very quickly.
Atmospheric researcher Prof. Joachim Curtius from Goethe University explains: "Iodine aerosols can form faster than almost all other aerosol types we know. If ions produced by cosmic rays are added, each collision leads to the growth of the molecular clusters." Curtius added that this is particularly important because global iodine emissions on Earth have already tripled over the past 70 years. "A vicious circle may have been set in motion here: The pack ice thaws, which increases the water surface area and more iodine enters the atmosphere. This leads to more aerosol particles, which form clouds that further warm the poles. The mechanism we found can now become part of climate models, because iodine may play a dominant role in aerosol formation, especially in the polar regions, and this could improve climate model predictions for these regions."
The CLOUD experiment (Cosmics Leaving OUtdoor Droplets) at CERN studies how new aerosol particles are formed in the atmosphere out of precursor gases and continue to grow into condensation seeds. CLOUD thereby provides fundamental understanding of the formation of clouds and particulate matter. CLOUD is carried out by an international consortium consisting of 21 institutes. The CLOUD measurement chamber was developed with CERN know-how and is one of the cleanest experimental rooms in the world. CLOUD measurement campaigns use a variety of different measuring instruments to characterise the physical and chemical state of the particles and gases that make up the atmosphere. The team led by Joachim Curtius from the Institute for Atmosphere and Environment at Goethe University Frankfurt developes and operates two mass spectrometers in the CLOUD project to detect trace gases such as iodic acid and iodous acid even in the smallest concentrations.
Publication: Xu-Cheng He, Yee Jun Tham, Lubna Dada, Mingyi Wang, Henning Finkenzeller, Dominik Stolzenburg, Siddharth Iyer, Mario Simon, Andreas Kürten, et. al. Role of iodine oxoacids in atmospheric aerosol nucleation, Science 05 Feb 2021: Vol. 371, Issue 6529, pp. 589-595, https://doi.org/10.1126/science.abe0298
Prof. Joachim Curtius
Institute for Atmosphere and Environment
Goethe University Frankfurt am Main
Tel: +49 69 798-40258
Dr. Andreas Kürten
Institute for Atmosphere and Environment
Goethe University Frankfurt am Main
Tel: +49 (69) 798-40256
Researchers from Frankfurt and Grenoble observe disulphide bridge formation in gamma-B crystalline for the first time in the ribosomal exit tunnel
Chemical bonds within the eye-lens protein gamma-B crystallin hold the protein together and are therefore important for the function of the protein within the lens. Contrary to previous assumptions, some of these bonds, called disulphide bridges, are already formed simultaneously with the synthesis of the protein in the cell. This is what scientists at Goethe University Frankfurt, Max Planck Institute of Biophysics and the French Institute de Biologie Structurale in Grenoble have discovered.
FRANKFURT. The lens of the human eye gets its transparency and refractive power from the fact that certain proteins are densely packed in its cells. These are mainly crystallines. If this dense packing cannot be maintained, for example due to hereditary changes in the crystallines, the result is lens opacities, known as cataracts, which are the most common cause of vision loss worldwide.
In order for crystallins to be packed tightly in lens fibre cells, they must be folded stably and correctly. Protein folding already begins during the biosynthesis of proteins in the ribosomes, which are large protein complexes. Ribosomes help translate the genetic code into a sequence of amino acids. In the process, ribosomes form a protective tunnel around the new amino acid chain, which takes on three-dimensional structures with different elements such as helices or folded structures immediately after the tunnel's formation. The gamma-B crystallines studied in Frankfurt and Grenoble also exhibit many bonds between two sulphur-containing amino acids, so-called disulphide bridges.
The production of these disulphide bridges is not easy for the cell, since biochemical conditions prevail in the cell environment that prevent or dissolve such disulphide bridges. In the finished gamma-B crystalline protein, the disulphide bridges are therefore shielded from the outside by other parts of the protein. However, as long as the protein is in the process of formation, this is not yet possible.
But because the ribosomal tunnel was considered too narrow, it was assumed - also on the basis of other studies - that the disulphide bridges of the gamma-B crystallins are formed only after the proteins have been completed. To test this assumption, the researchers from Frankfurt and Grenoble used genetically modified bacterial cells as a model system, stopped the synthesis of the gamma-B crystallins at different points in time and examined the intermediate products with mass spectrometric, nuclear magnetic resonance spectroscopic and electron microscopic methods, and supplemented these with theoretical simulation calculations. The result: The disulphide bridges are already formed on the not yet finished protein during the synthesis of the amino acid chain.
"We were thus able to show that disulphide bridges can already form in the ribosomal tunnel, which offers sufficient space for this and shields the disulphide bridges from the cellular milieu," says Prof. Harald Schwalbe from the Institute of Organic Chemistry and Chemical Biology at Goethe University. "Surprisingly, however, these are not the same disulphide bridges that are later present in the finished gamma-B crystallin. We conclude that at least some of the disulphide bridges are later dissolved again and linked differently. The reason for this probably lies in the optimal timing of protein production: the 'preliminary' disulphide bridges accelerate the formation of the 'final' disulphide bridges when the gamma-B crystallin is released from the ribosome."
In further studies, the researchers now want to test whether the synthesis processes in the slightly different ribosomes of higher cells are similar to those in the bacterial model system.
Publication: Linda Schulte, Jiafei Mao, Julian Reitz, Sridhar Sreeramulu, Denis Kudlinzki,
Victor-Valentin Hodirnau, Jakob Meier-Credo, Krishna Saxena, Florian Buhr, Julian D. Langer, Martin Blackledge, Achilleas S. Frangakis, Clemens Glaubitz, Harald Schwalbe: Cysteine oxidation and disulfide formation in the ribosomal exit tunnel. Nature Communications https://doi.org/10.1038/s41467-020-19372-x
Prof. Dr. Harald Schwalbe
Institute for Chemistry and Chemical Biology
Center for Biomolecular Magnetic Resonance (BMRZ)
Goethe University Frankfurt
Tel +49 69 798-29137
Goethe University honours patron, romantic arts lover and doctor Klaus Heyne
FRANKFURT. For the first time in 2021, innovative contributions to the study of Romanticism can be awarded the Goethe University’s Klaus Heyne-Award. The new award, endowed with 15,000 euros, is aimed at early-career scholars from Germany and abroad who are in a phase of academic qualification and have made an outstanding contribution to Romanticism research.
The new award has been made possible by a generous bequest from the paediatrician Professor Klaus Heyne (1937-2017), whose had a particular passion for the arts and literature of German Romanticism. Frankfurt literary scholar Professor Frederike Middelhoff says: "We are very grateful that we can support young scholars with this award which is also significantly benefits Romanticism research at Goethe University."
The Klaus Heyne-Award, which is meant to be conferred every two years, consists of two components: 5,000 euros will be awarded on a non-earmarked basis; 10,000 euros will be made available for the organisation of a conference on Romantic Studies to be hosted at Goethe University in 2022 and supported by the Frankfurt Chair of Modern German Literature with a Focus on Romantic Studies.
The award winner is to be honoured at a ceremony in October 2021 (currently planned as an in-person event but will be organised online if necessary).
Interested researchers please contact:
Prof. Dr. Frederike Middelhoff
Chair of Modern German Literature with a focus on Romantic Studies
Researchers develop robust approach for detecting market manipulation
Social media is increasingly used to spread fake news. The same problem can be found on the capital market – criminals spread fake news about companies in order to manipulate share prices. Researchers at the Universities of Göttingen and Frankfurt and the Jožef Stefan Institute in Ljubljana have developed an approach that can recognise such fake news, even when the news contents are repeatedly adapted. The results of the study were published in the Journal of the Association for Information Systems.
FRANKFURT. In order to detect false information – often fictitious data that presents a company in a positive light – the scientists used machine learning methods and created classification models that can be applied to identify suspicious messages based on their content and certain linguistic characteristics.
"Here we look at other aspects of the text that makes up the message, such as the comprehensibility of the language and the mood that the text conveys," says Professor Jan Muntermann from the University of Göttingen. The approach is already known in principle from its use by spam filters, for example. However, the key problem with the current methods is that to avoid being recognised, fraudsters continuously adapt the content and avoid certain words that are used to identify the fake news.
This is where the researchers' new approach comes in: to identify fake news despite such strategies to evade detection, they combine models recently developed by the researchers in such a way that high detection rates and robustness come together. So even if "suspicious" words disappear from the text, the fake news is still recognised by its linguistic features. "This puts scammers into a dilemma. They can only avoid detection if they change the mood of the text so that it is negative, for instance," explains Dr Michael Siering. "But then they would miss their target of inducing investors to buy certain stocks."
The new approach can be used, for example, in market surveillance to temporarily suspend the trading of affected stocks. In addition, it offers investors valuable information to avoid falling for such fraud schemes. It is also possible that it could be used for criminal prosecutions in the future.
Publication: Michael Siering, Jan Muntermann, Miha Grčar. Design Principles for Robust Fraud Detection: The Case of Stock Market Manipulations. Journal of the Association for Information Sys-tems (2021). https://aisel.aisnet.org/jais/vol22/iss1/4
Dr Michael Siering
Goethe University Frankfurt
Economics and Business Administration
Chair of e-Finance
Professor Jan Muntermann
University of Göttingen
Faculty of Business and Economics
Professor of Electronic Finance and Digital Markets
Tel: +49 (0)551 39 27062
Findings of the PREDICT study on acute decompensation and acute-on-chronic liver failure
Acute-on-chronic liver failure (ACLF) is a common cause of death in patients with cirrhosis. In ACLF the progressive loss of function of the scarred liver can no longer be compensated (acute decompensation). As a result, other organs such as the kidney or brain fail. The triggers for acute decompensation of liver cirrhosis and an ACLF are most frequently bacterial infections, liver inflammation caused by alcohol, or a combination of both factors. This was revealed by the evaluation of the PREDICT study, which was conducted by an international team of researchers led by Professor Jonel Trebicka from the University Hospital Frankfurt.
FRANKFURT. Chronic liver disease and even cirrhosis can go unnoticed for a long time because many patients have no symptoms: the liver suffers silently. When the body is no longer able to compensate for the liver's declining performance, the condition deteriorates dramatically in a very short time: tissue fluid collects in the abdomen (ascites), internal bleeding occurs in the oesophagus and elsewhere, and the brain is at risk of being poisoned by metabolic products. This acute decompensation of liver cirrhosis can develop into acute-on-chronic liver failure with inflammatory reactions throughout the body and failure of several organs.
In the PREDICT study, led by Professor Jonel Trebicka, scientists from 15 European countries observed 1273 patients who were hospitalized with acute decompensation of their liver cirrhosis. The current evaluation of the study focused on the question of what can trigger acute decompensation of liver cirrhosis. The result: in the vast majority of cases (>90%), a bacterial infection, liver inflammation caused by alcohol consumption, or both together could be identified as the trigger.
Bleeding in the digestive tract and brain dysfunction induced by painkillers or sedatives (drug-induced toxic encephalopathy) were identified as further trigger, although at a lower rate.
Lead investigator Professor Jonel Trebicka, gastroenterologist and hepatologist at the Medical Clinic I of the University Hospital Frankfurt, explains: "The acute decompensation of liver cirrhosis demands rapid and targeted action. In the PREDICT study, we therefore want to learn a lot about the triggering factors of this life-threatening disease in order to be able to derive recommendations for diagnostics and therapy. Knowing what the most likely triggers of acute decompensation are will help to further develop diagnostic and treatment strategies for patients with this life-threatening disease."
The pan-European PREDICT study has monitored the clinical course of acute decompensations of liver cirrhosis to find early signs of the development of acute-on-chronic liver failure (ACLF). PREDICT is funded by the European Foundation for the Study of Chronic Liver Failure. A total of 136 scientists from 47 centres and institutions in 15 European countries are participating in PREDICT.
Publication: Jonel Trebicka, Javier Fernandez, et al. for the PREDICT STUDY group of the EASL-CLIF CONSORTIUM: PREDICT identifies precipitating events associated with the clinical course of acutely decompensated cirrhosis. Journal of Hepatology (2020), https://doi.org/10.1016/j.jhep.2020.11.019
University Hospital Frankfurt, Goethe University Frankfurt
Medical Clinic I
Professor Jonel Trebicka
Section Translational Hepatology,
Medical Clinic I (Director: Professor Stefan Zeuzem)
Goethe University/University Hospital Frankfurt
Tel. +49 69 6301 80789 (Jennifer Biondo, secretarial office)
European Foundation for the Study of Chronic Liver Failure (EF Clif) is a private, non-profit Foundation whose mission is to promote study
and research on Acute-on-Chronic Liver Failure and thus, contribute to
improving both the quality of life and survival of patients with liver
The EF Clif was created in 2015 to support the research work carried out by the EASL Clif Consortium, a research network of more than 100 European University Hospitals and 200 clinical investigators. In 2013, the Consortium described a new syndrome: Acute-on-Chronic Liver Failure (ACLF), which is the most common cause of death in cirrhosis.
Currently, the research activity of the EF Clif is fostered through two chairs: the EASL Clif Chair, to promote observational, pathophysiological and therapeutic studies through the EASL-Clif Consortium's hospital network; and the Grifols Chair, which promotes the development of translational research projects with the creation of a network of centres across Europe: The European Network for Translational Research in Chronic Liver Failure (ENTR-CLIF).
To know more about the EF Clif: http://www.efclif.com Twitter: @ef_clif