Press releases

FRANKFURT. Atmospheric researchers from Goethe University have demonstrated that air purifiers with a class H13 filter (HEPA) can lower aerosol concentration in a classroom by 90 percent within 30 minutes. Because this significantly reduces the risk of airborne infection with SARS-CoV-2, the scientists recommend placing such air purifiers in classrooms. In most cases, students and teachers did not find the noise made by the purifier disturbing. The study is now available as a preprint, prior to appearing in a scientific journal. (https://doi.org/10.1101/2020.10.02.20205633)

The most dangerous route to an infection with SARS-CoV-2 is via the air: For example, when infected persons sneeze or cough, they catapult relatively large droplets which, however, sink to the ground within a radius of two metres. Important are also aerosols, much smaller droplets, which we emit when speaking or breathing. Studies show that infectious SARS-CoV-2 pathogens can still be detected in such aerosols over three hours after emission and several metres away from an infected person. The fluid in such aerosol particles evaporates quickly, making them smaller and able to disperse in a room within a few minutes.

Together with his team, Joachim Curtius, Professor for Experimental Atmospheric Research at Goethe University, tested four air purifiers in a classroom with 27 students and their teachers over a period of a week. The purifiers had a simple prefilter for coarse dust particles and fluff as well as HEPA and active carbon filters. Together, the filters processed between 760 and 1,460 m3 of air per hour. Apart from aerosol load, the researchers also measured the volume of fine dust particles and CO2 concentration and analysed the noise levels caused by the device. The result: Half an hour after switching it on, the air purifiers had removed 90 percent of the aerosols from the air.

Professor Curtius explains: “On the basis of our measurement data, we've calculated a model that allows the following estimate: An air purifier lowers the amount of aerosols to such a considerable degree that the risk of being infected by a highly contagious person, a superspreader, is greatly reduced. That's why we're recommending that schools use HEPA air purifiers this winter with a sufficiently high air flow rate."

Noise measurements and a survey among students and teachers revealed that in most cases the noise made by the air purifier was not considered disturbing, provided that the appliance was not running at the highest level.

The researchers also measured that the air purifier – apart from lowering the risk of infection –additionally reduced allergens and fine dust particles (PM10). Joachim Curtius: “An air filter does not, however, replace opening the window at regular intervals, which is important for decreasing CO2 concentration in the room. Our measurements in the classrooms showed that levels often exceeded the recommended limits. Here, we recommend installing CO2 sensors so that students and teachers can monitor this themselves."


Publication: Joachim Curtius, Manuel Granzin, Jann Schrod: Testing mobile air purifiers in a school classroom: Reducing the airborne transmission risk for SARS‐CoV‐2. Preprint: medRxiv 2020.10.02.20205633; doi: https://doi.org/10.1101/2020.10.02.20205633

Further information:
Professor Dr. Joachim Curtius
Institute for Atmospheric and Environmental Sciences
Goethe University
Tel.: +49 69 798-40258
curtius@iau.uni-frankfurt.de

FRANKFURT. Geoscientists from Goethe University have found the largest extraterrestrial diamonds ever discovered – a few tenths of a millimetre in size nevertheless – inside meteorites. Together with an international team of researchers, they have now been able to prove that these diamonds formed in the early period of our solar system when minor planets collided together or with large asteroids. These new data disprove the theory that they originated deep inside planets – similar to diamonds formed on Earth - at least the size of Mercury. (PNAS, https://www.pnas.org/content/early/2020/09/22/1919067117)

It is estimated that over 10 million asteroids are circling the Earth in the asteroid belt. They are relics from the early days of our solar system, when our planets formed out of a large cloud of gas and dust rotating around the sun. When asteroids are cast out of orbit, they sometimes plummet towards Earth as meteoroids. If they are big enough, they do not burn up completely when entering the atmosphere and can be found as meteorites. The geoscientific study of such meteorites makes it possible to draw conclusions not only about the evolution and development of planets in the solar system but also their extinction.

A special type of meteorites are ureilites. These are fragments of a larger celestial body – probably a minor planet – which was smashed to pieces through violent collisions with other minor planets or large asteroids. Ureilites often contain large quantities of carbon, among others in the form of graphite or nanodiamonds. The diamonds on the scale of over 0.1 and more millimetres now discovered cannot have formed when the meteoroids hit the Earth. Impact events with such vast energies would make the meteoroids evaporate completely. That is why it was so far assumed that these larger diamonds – similar to those in the Earth's interior – must have been formed by continuous pressure in the interior of planetary precursors the size of Mars or Mercury.  

Together with scientists from Italy, the USA, Russia, Saudi Arabia, Switzerland and the Sudan, researchers from Goethe University have now found the largest diamonds ever discovered in ureilites from Morocco and the Sudan and analysed them in detail. Apart from the diamonds of up to several 100 micrometres in size, numerous nests of diamonds on just nanometre scale as well as nanographite were found in the ureilites. Closer analyses showed that what are known as londsdalite layers exist in the nanodiamonds, a modification of diamonds that only occurs through sudden, very high pressure. Moreover, other minerals (silicates) in the ureilite rocks under examination displayed typical signs of shock pressure. In the end, it was the presence of these larger diamonds together with nanodiamonds and nanographite that led to the breakthrough.

Professor Frank Brenker from the Department of Geosciences at Goethe University explains:
“Our extensive new studies show that these unusual extraterrestrial diamonds formed through the immense shock pressure that occurred when a large asteroid or even minor planet smashed into the surface of the ureilite parent body. It's by all means possible that it was precisely this enormous impact that ultimately led to the complete destruction of the minor planet. This means – contrary to prior assumptions – that the larger ureilite diamonds are not a sign that protoplanets the size of Mars or Mercury existed in the early period of our solar system, but nonetheless of the immense, destructive forces that prevailed at that time."


The international research team comprises scientists from the following institutions:

Department of Geosciences, University of Padova, Italy
Department of Geosciences, Goethe University, Frankfurt, Germany
Lunar and Planetary Institute, USRA, Houston, Texas, USA
Department of Earth and Environmental Sciences, University of Pavia, Italy
Astromaterials Research and Exploration Science Division, Jacobs JETS, Johnson Space Center, NASA, Houston, Texas, USA
CNR Institute of Geosciences and Earth Resources, Padua, Italy
Vereshchagin Institute for High Pressure Physics RAS, Troitsk, Moscow, Russia
NASA Astromaterials Acquisition and Curation Office, Johnson Space Center, NASA, Houston, Texas, USA
Department of Civil, Environmental and Mechanical Engineering, University of Trento, Italy
Saudi Aramco R&D Center, Dhahran, Saudi Arabia
Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
SETI Institute, Mountain View, California, USA
Department of Physics and Astronomy, University of Khartoum, Khartoum, Sudan


Publication: Fabrizio Nestola, Cyrena A. Goodrich, Marta Morana, Anna Barbaro, Ryan S. Jakubek, Oliver Christ, Frank E. Brenker, Maria C. Domeneghetti, Maria C. Dalconi, Matteo Alvaro, Anna M. Fioretti, Konstantin Litasov, Marc D. Fries, Matteo Leoni, Nicola P. M. Casati, Peter Jenniskens, Muawia H. Shaddad: Impact shock origin of diamonds in ureilite meteorites. Proceedings of the National Academy of Science https://www.pnas.org/content/early/2020/09/22/1919067117

Images to download:
Picture1: Planetary collision
Caption: Artist's impression of the collision of two protoplanets. Credits: NASA/SOFIA/Lynette Cook
https://www.nasa.gov/image-feature/what-happens-when-planets-collide

Picture2: Rock sample from ureilite minor planet
Caption: Photo of a rock sample from the ureilite minor planet, found as a meteorite in the Sahara. Length of the fragments about 2cm. Credits: Oliver Christ https://www.muk.uni-frankfurt.de/92537913

Picture3: Colour coded Raman spectroscopic map of the ureilite studied. diamond (red), graphite (blue). Credits: Cyrena Goodrich http://www.uni-frankfurt.de/92538164


Further information:
Professor Frank E. Brenker
Department of Geosciences / NanoGeoscience
Goethe University
Tel: +49 69 798 40134
f.brenker@em.uni-frankfurt.de

FRANKFURT. Researchers at Goethe University Frankfurt and the university of Würzburg have developed a new compound for treating cancer. It destroys a protein that triggers its development.

The villain in this drama has a pretty name: Aurora – Latin for dawn. In the world of biochemistry, however, Aurora (more precisely: Aurora-A kinase) stands for a protein that causes extensive damage. There, it has been known for a long time that Aurora often causes cancer. It triggers the development of leukemias and many pediatric cancers, such as neuroblastomas.

Researchers at the universities of Frankfurt and Würzburg have now developed a drug that can disarm Aurora. Stefan Knapp, Professor of Pharmaceutical Chemistry at Goethe University Frankfurt, and Dr. Elmar Wolf, biochemist and research group leader at the Biocenter of Julius-Maximilians-Universität Würzburg (JMU), have played a leading role in this development. The results of their work have now been published in the latest issue of Nature Chemical Biology.

Making tumor-promoting proteins disappear

Cancers are usually triggered by tumorigenic proteins. Because cancer cells produce more of these proteins than normal cells, the dynamics are additionally increased. A common therapeutic approach is therefore to inhibit the function of these proteins with drugs. Although the proteins are then still there, they no longer function as well. This makes it possible to combat the tumor cells.
 
However, the development of these inhibitors is difficult and has so far not been successful for all tumor-promoting proteins. To date, none of the candidates that inhibit Aurora has shown the desired results in clinical practice. The dream of many scientists is therefore to develop a drug that not only inhibits the tumor-promoting proteins but makes them disappear completely. A promising approach along this path could be a new class of substances with the scientific name “PROTAC".

In vitro cancer cells die

“We have developed such a PROTAC for Aurora," says Elmar Wolf. This PROTAC completely degrades the Aurora protein in cancer cells. Such cells cultivated in the laboratory died as a result. Wolf describes the mode of action of this substance as follows: “The tumor needs certain tumor-promoting proteins, which we can imagine as the pages of a book. Our PROTAC substance tears out the 'Aurora' pages and destroys them with the help of the machinery that every cell has to degrade old and broken proteins." PROTAC thus “shreds" the Aurora protein, as it were, until nothing of it remains.

Professor Stefan Knapp from the Institute of Pharmaceutical Chemistry at Goethe University explains: “Aurora-A kinase is present in much higher concentrations in many cancer tissues than in healthy tissue and it also plays a key role in prostate cancer. Blocking the activity of Aurora-A kinase alone seems not a promising approach as none of the many clinically tested drug candidates has achieved clinical approval. With our PROTAC variant, we inhibit Aurora-A kinase via another, possibly more effective mechanism, which may open up new treatment options. That's why in the next step we'll test effectiveness and tolerance in animal models."


Publication: PROTAC-mediated degradation reveals a non-catalytic function of AURORA-A kinase. Bikash Adhikari, Jelena Bozilovic, Mathias Diebold, Jessica Denise Schwarz, Julia Hofstetter, Martin Schröder, Marek Wanior, Ashwin Narain, Markus Vogt, Nevenka Dudvarski Stankovic, Apoorva Baluapuri, Lars Schönemann, Lorenz Eing, Pranjali Bhandare, Bernhard Kuster, Andreas Schlosser, Stephanie Heinzlmeir, Christoph Sotriffer, Stefan Knapp and Elmar Wolf. Nature Chemical Biology, 28.09.2020. https://www.nature.com/articles/s41589-020-00652-y

PROTACS: The cluster project PROXIDRUGS at Goethe University Frankfurt focuses on PROTACS (Proteolysis Targeting Chimeric Molecules): https://aktuelles.uni-frankfurt.de/englisch/proxidrugs-project-led-by-goethe-university-included-in-clusters4future-programme/

Further Information:
Prof. Dr. Stefan Knapp
Institut of Pharmaceutical Chemistry
Goethe University Frankfurt
Phone: +49 69 798 29871
knapp@pharmchem.uni-frankfurt.de

FRANKFURT. Walter Benjamin's collection of children's books is to be saved for posterity. The national government, the Federal State of Hesse and the Department for Children's and Young Adult Literature Research have joined forces to finance the first restoration work on this valuable historical archive.

The collection previously owned by Walter Benjamin comprises just 204 books. Yet it is particularly valuable in several respects: For research, it delivers important insights into this great intellectual mind, who was a close friend of Theodor W. Adorno and belonged to the circle of the Frankfurt School. Some of the books stem from Benjamin's own childhood, and in his writings and radio broadcasts he also dealt with children's literature based on his collection. Moreover, the collection is composed entirely of beautiful and rare copies: Benjamin, who was born in Berlin, primarily built up his collection according to aesthetic criteria; he was especially interested in illustrated and artistically ornate children's books.

Having been purchased from Benjamin's heirs, the collection came to the Department for Children's and Young Adult Literature Research in the 1980s. It was the explicit wish of Stefan Benjamin, Walter Benjamin's son, that the collection return to Germany. It was displayed at an exhibition at the University Library and an elaborate catalogue was produced (available for download from the department's website: www.uni-frankfurt.de/65668457/Die_Kinderbuchsammlung_Walter_Benjamin_Katalog.pdf).

Since then, the books have been kept in a steel cabinet in the department's library. To be able to continue making them accessible for research, restoration work is urgently required: The books are used a great deal and partially damaged as a result, the ravages of time have done the rest. They will now first be “stabilised". Part of the collection has already been sent to the Centre for Book Conservation in Leipzig, where first of all the paper will be deacidified, the cover and edges stabilised, and customised boxes with hinged lids made for each individual book.

“With modest means, Benjamin assembled the books from his own childhood into a collection," explains Dr Felix Giesa, custodian at the Department for Children's and Young Adult Literature Research. He primarily collected books according to aesthetic criteria, he adds, mostly illustrated works from the 19th century. Apart from various editions of Grimms' Children's and Household Tales, fairytales by Wilhelm Hauff and Charles Perrault are also part of the collection. In addition, what are known as transformation picture books, such as a rare book by Christian Gottfried Heinrich Geissler dated 1815, make up an important part of the valuable collection.

With funds from the government's Coordination Office for the Preservation of Written Cultural Heritage, which will assume 50 percent of the costs, from the Federal State of Hesse, which will bear 40 percent via the Hessian Ministry of Higher Education, Research, Science and the Arts, and from the budget of Professor Ute Dettmar, the collection will first be stabilised and catalogued, after which an exhibition and a symposium are planned. A total of around € 30,000 is available for these measures. Later, the collection will also be digitised so that it is available for Benjamin research in Germany and abroad – without its use leaving further traces in the originals.


Images can be downloaded under the following link: http://www.uni-frankfurt.de/92258379

Caption: Much-used and correspondingly worse for wear: Walter Benjamin's collection of children's books is to be saved for posterity. Funds for this are now available. (Photo: Uwe Dettmar)

The ALICE experiment at the particle accelerator CERN in Geneva has the aim of providing new insights into an extremely hot and dense state of matter, the quark-gluon plasma. The entire matter of the universe was in this state just a few millionths of a second after the big bang, and the ALICE experiment will help researchers discover how the universe developed out of this primordial soup. An international team of scientists led by the physicist Harald Appelshäuser from Goethe University Frankfurt have therefore upgraded the centrepiece of the ALICE detector to current state of the art technology.

FRANKFURT. For the moment, the accelerators at CERN are at rest during the “second long shutdown". During this time, the accelerators undergo upgrades and refurbishments so that more particles can be accelerated and the number of collisions will increase in the future. The detectors are also undergoing upgrades. But while the large all-purpose detectors ATLAS and CMS are not scheduled for larger upgrades until the next, and third long shutdown in 2025, the specialised detector ALICE will enter the upcoming measurement campaign already upgraded.

ALICE is a unique project among the research adventures surrounding CERN's Large Hadron Collider (LHC). While the other three detectors decipher what occurs in collisions of protons, the researchers in the ALICE experiment are concerned with lead ions – particles that are many times heavier. Each year, the LHC is operated with lead ions for one month so that the ALICE detector can collect data. The researchers want to learn more about a particular state of matter: quark-gluon-plasma. It is created inside the ALICE experiment when lead nuclei collide with each other at high energy and are dissolved into their elementary components for a short moment. In this hot and dense soup of matter, quarks and gluons, otherwise firmly attached in the protons and neutrons, can move around virtually freely. What happens during the collisions may provide insight into how our universe as we know it today was formed out of a giant primordial out of quark-gluon plasma.

Recording a movie instead of taking individual pictures

After the shutdown, the upgraded ALICE detector will show what it can now do: previously, the LHC accelerator delivered 10,000 collisions per second. At 18,000 particles per collision this amounts to 180 million particles per second, only a portion of which was able to be recorded by the ALICE detector. After the shutdown, the technological hurdles which have until now limited the number of recorded collisions will have been eliminated. The LHC should then deliver 50,000 collisions of lead ions per second, resulting in 900 million particles per second. “We want to record all collisions in entirety and, in fact, continuously, in other words, to record a movie instead of individual pictures," explains Harald Appelshäuser, Professor at the Institute for Nuclear Physics at Goethe University Frankfurt and project leader of the subdetector that will make the biggest difference after the upgrade.

Detector under construction

To achieve this, one of the central detectors of the 26-metre long and 16-metre high ALICE detector complex, the Time Projection Chamber (TPC), was removed and carefully brought from the underground detector cavern into a clean room on the surface. Different parts that were developed all over the world during the past several years were gradually and carefully installed. Now the technologically upgraded TPC has been returned to its home at the heart of ALICE.

The highlights are the new readout chambers which no longer consist of many fine wires, but basically of about five billion tiny holes. In these holes, the signals of the charged particles will be amplified so that the scientists can precisely calculate the track of each particle. These chambers are called “GEMs" – Gas Electron Multipliers – and are a CERN invention which has already found its way into medical procedures. 500,000 channels ensure that nothing escapes the ALICE experiment. Each second during the collisions later results in 3.4 terabytes of data.

New procedures must also be developed which can process this flood of data. With the participation of high-performance computing expert Professor Volker Lindenstruth and his colleagues, scientists from Goethe University will be playing a leading role here as well.  “We now have the finest of the fine and look forward to the first collisions," says Appelshäuser.

The new GEM readout chambers were custom fit for the ALICE experiment through testing and development in Germany – at Goethe University Frankfurt as well as at the Bonn and Heidelberg Universities, the Technical University Munich, and the GSI Helmholtzzentrum für Schwerionenforschung, and later assembled in different countries which in addition to Germany included Hungary, Finland, Romania and the USA. “The logistics were pretty complicated," explains project leader Appelshäuser. “The TPC was brought to the clean room in 2019 that was where we removed the older chambers and installed and tested the new ones. Luckily, we had just finished before the pandemic started."

During the shutdown ALICE will also receive a new inner tracking chamber, positioned closer to the collision point and further increasing precision compared to its predecessor. And the detectors have to be precise, for only through exact determination of particle paths and particle energies can conclusions be reached about the first split seconds of the universe.

Images may be downloaded here: http://www.uni-frankfurt.de/92047073

Caption: Working on the ALICE detector under corona conditions: from the left: Robert Münzer (Goethe University Frankfurt, GU), Chilo Garabatos (GSI Helmholtzzentrum für Schwerionenforschung), Lars Bratrud (GU), Yiota Chatzidaki (Heidelberg University), Christian Lippmann (GSI).
Credit: Robert Münzer

Additional images for download at CERN:
https://cds.cern.ch/record/2727174#

Further information:
Prof. Dr. Harald Appelshäuser
Institute for Nuclear Physics
Goethe University
Phone: +49 69 798-47034 or 47023
appels@ikf.uni-frankfurt.de