Potential applications as nano semiconductor materials
Chemists at Goethe University Frankfurt have developed two new classes of materials in the field of nanomaterials and investigated them together with their cooperation partners at the University of Bonn: for the first time, they have succeeded in producing a nano sphere of silicon atoms and a building block for a diamond-like crystal of the semiconductor elements silicon and germanium. The two new classes of materials have potential applications in the miniaturisation of computer chips, in high-resolution screens for smartphones, and in solar cells and light-emitting diodes with the highest levels of efficiency.
FRANKFURT. The latest generations of computer chips are only a few nanometres in size and are becoming ever more energy-saving and powerful as a result of progressive miniaturisation. Since the etching processes traditionally used in chip production are increasingly reaching their limits, the development of new, nanostructured semiconductor materials is essential. Such nano semiconductors also play a central role in converting electricity into light and vice versa.
A team at Goethe University Frankfurt led by Matthias Wagner has now succeeded in synthesising molecular nano "spheres" made of 20 silicon atoms, so-called silafulleranes. The second new class of materials are crystal building blocks made of 10 silicon and germanium atoms that have a diamond-like structure. Decisive insights into the electronic structures of the new compounds were provided by computer-based theoretical analyses from Stefan Grimme's research group in Bonn.
The 20 silicon atoms of silafullerane form a dodecahedron, a body composed of regular pentagons. It encapsulates a chloride ion. A hydrogen atom protrudes outward at each silicon corner of the body. Doctoral student Marcel Bamberg, who synthesised the molecule, explains: "Our silafullerane is the long-sought progenitor of this new class of substances. The hydrogen atoms can easily be replaced with functional groups, thus giving the silafullerane different properties." Bonn quantum chemist Markus Bursch adds: "We support the targeted generation of potentially useful properties with theoretical predictions of their resulting effects."
The silicon-germanium adamantane represents the building block of a mixed silicon-germanium alloy. Benedikt Köstler, who is developing the compounds as part of his doctoral thesis, says: "Recent studies have shown that silicon-germanium alloys are superior to pure silicon semiconductors in important application areas. However, the production of such alloys is very difficult and you often get mixtures of different compositions. We have succeeded in developing a simple synthesis path for the basic building block of silicon-germanium alloys. Our silicon-germanium adamantane therefore enables the investigation of important chemical and physical properties of silicon-germanium alloys on the molecular model. We also want to use it in the future to produce silicon-germanium alloys with faultless crystal structures."
Carbon, which is chemically very similar to the elements silicon and germanium, occurs in comparable forms to the two new classes of substances: Hollow spheres of carbon atoms ("fullerenes") correspond to silafulleranes, and diamonds consisting of carbon are composed of adamantane subunits. Among other things, fullerenes increase the efficiency of organic solar cells, could make the batteries of electric cars safer, and promise progress in high-temperature superconductivity. Nanodiamonds also have a wide range of applications, from pharmaceuticals to catalysis research.
Against this background, the researchers in Frankfurt and Bonn are excited to see in which fields their silafulleranes and silicon-germanium adamantanes will become established. Matthias Wagner says: "It is already possible to generate light in all colours of the visible spectrum with nanostructured silicon and germanium in the form of quantum dots, and this is being tested for computer and mobile phone displays, as well as in telecommunications. Apart from the chemical-technical potential, I am personally fascinated by the high symmetry of our compounds: For example, our silafullerane is one of the five Platonic solids and possesses a timeless beauty."
(1) Marcel Bamberg, Markus Bursch, Andreas Hansen, Matthias Brandl, Gabriele Sentis, Lukas Kunze, Michael Bolte, Hans-Wolfram Lerner, Stefan Grimme, Matthias Wagner: [Cl@Si20H20]−: Parent Siladodecahedrane with Endohedral Chloride Ion. J. Am. Chem. Soc. 2021, 143, 10865–10871 https://doi.org/10.1021/jacs.1c05598
(2) Benedikt Köstler, Michael Bolte, Hans-Wolfram Lerner, Matthias Wagner: Selective One-Pot Syntheses of Mixed Silicon-Germanium Heteroadamantane Clusters. Chem. Eur. J. https://doi.org/10.1002/chem.202102732 Images for download: https://www.uni-frankfurt.de/105049499
(1) The silicon sphere [Cl@Si20H20]−, synthesised for the first time by chemists from Goethe University Frankfurt, promises new applications in semiconductor technology. Blue: silicon, green: chloride ion, grey: hydrogen. Graphic: Goethe University Frankfurt
(2) Building block for silicon-germanium alloys: A section of the silicon-germanium adamantane synthesised in Frankfurt (shown here without substituents). Blue: silicon, magenta: germanium. Graphic: Goethe University Frankfurt
Professor Matthias Wagner
Institute for Inorganic and Analytical Chemistry
Goethe University Frankfurt
Tel.: +49 69 798 29156
Researchers from Goethe University present review on the release of pollutants from sediments
A long-term hazard from flood water is often underestimated: The raging rivers swirl up pollutants out of their sediments that stem from environmental pollution decades or centuries ago. Such harmful substances can not only cause ecological damage in the river. They can also deposit themselves on flooded areas and affect crops, grazing livestock and humans. This has been pointed out by an international research team in a review of scientific studies on flood events throughout the world. The paper has been published in the Journal of Hazardous Materials and was produced under the leadership of Goethe University.
FRANKFURT. Sediments are regarded as a river's long-term memory. They mainly comprise particles that are eroded from the ground, ending up at some point in river deltas or the sea. However, sediments can also remain stable for a relatively long time – and bind pollutants which, for example, have entered the rivers through mining or industrial wastewater. As a consequence, many old river sediments contain pollutants as “chemical time bombs", such as heavy metals or dioxins and dioxin-like compounds that are not easily degradable.
During flood events in the more industrial regions of Europe, North America and Asia, old sediments can be churned up as a result of the high speeds at which the water is flowing. In the process, the pollutants bound in them are regularly released in one go and contaminate flooded areas. An interdisciplinary team of researchers from Goethe University, RWTH Aachen University and the University of Saskatchewan in Canada, along with other partners, has compiled a review of previous scientific studies on this topic. In it, the researchers, headed by junior research group leader Dr Sarah Crawford in Frankfurt and Canadian researcher Professor Markus Brinkmann, show, for example, which pollutant loads were measured after various flood events, which test systems were developed for different pollutants and how different sediments behave when water flows at high speeds. It describes the risks for drinking water production, the influence of temperature on pollutant intake by fish and methods for assessing the economic costs associated with the remobilisation of pollutants.
Despite the many years of research on this subject, Henner Hollert, professor of environmental toxicology at Goethe University and senior author of the publication in hand, is greatly concerned: “I have the impression that the problem of pollutants from old sediments is greatly underestimated in Germany and also in Europe as a whole. One reason for this could also be that to date there have been practically no studies at all on the economic consequences of this problem, as we've been able to show. However, contaminated sediments are a ticking time bomb that can explode each time there's a flood. What we need now is good river management across the board that not only looks at immediate hazards for humans, animals and infrastructure but also at the long-term consequences resulting from pollutants in the riverbeds. It's imperative, for example, that we examine flooded areas used agriculturally for river-specific pollutants so that these do not end up on our plates in the form of meat and dairy products."
In an interdisciplinary approach, researchers
from Goethe University Frankfurt, in collaboration with RWTH Aachen University,
the University of Saskatchewan in Canada, the Helmholtz Centre for
Environmental Research in Leipzig, the Institute for Social-Ecological Research
(ISOE), the Senckenberg Institute, the LOEWE Centre for Translational Biodiversity
Genomics and many other partners, are also studying the recent extreme flood
events in Rhineland-Palatinate and North Rhine-Westphalia in terms of hydraulic
engineering and the biological, ecotoxicological, ecological, geoscientific but
also the social-ecological and economic consequences. These studies are
embedded in the new research cluster RobustNature at Goethe University, which is
examining the robustness and resilience of nature-society systems in the
changing Anthropocene and aims to contribute to knowledge-based transformation
research using the examples of biodiversity and water – that is, from knowledge
Publication: Sarah E. Crawford, Markus Brinkmann, Jacob D. Ouellet, Frank Lehmkuhl, Klaus Reicherter, Jan Schwarzbauer, Piero Bellanova, Peter Letmathe, Lars M. Blank, Roland Weber, Werner Brack, Joost T. van Dongen, Lucas Menzel, Markus Hecker, Holger Schüttrumpf & Henner Hollert: Remobilization of pollutants during extreme flood events poses severe risks to human and environmental health. Journal of Hazardous Materials 421 (2022) 126691 https://doi.org/10.1016/j.jhazmat.2021.126691
The article is freely accessible from the publisher's following link for the next six weeks: https://authors.elsevier.com/c/1dSu515DSlK2Np
material can be
Caption: The remobilisation of pollutants from sediments during severe flooding is a so far underestimated consequence of extreme events. Graphics: Crawford, S. et al. (2021) J. Haz. Mat.
Professor Henner Hollert
Department of Evolutionary Ecology and Environmental Toxicology
Institute of Ecology, Diversity and Evolution
LOEWE Centre for Translational Biodiversity Genomics
Phone +49 69 798-42171 and +49-151-14042119
Korean Studies at Goethe University receives € 700,000 to further develop its work / From 20 to 400 students in ten years
Korean Studies at Goethe University is one of what are known as “rare disciplines" (subjects with a small number of professors taught in only a few locations), so it is all the more impressive that it has now secured € 700,000 in third-party funding. The money is being invested in the project “Cultivating diversity: The global in Korea, Korea in the global" and should contribute to advancing teaching, research and regional collaboration in the field of Korean Studies.
FRANKFURT. Since 2010, there has been an area studies section at Goethe University dedicated to Korean Studies, hosted by the Institute of East Asian Philology. The number of students has risen from 20 at the outset to 400 today – and interest is continuing to grow, says Yonson Ahn, who, as the only professor for this subject, teaches Korean culture and society at the university. With the support of third-party funding, she can now better meet the growing demand for courses in this subject. The Academy of Korean Studies (AKS) has pledged around € 700,000 in funding for the next five years, which will be invested in research, teaching and outreach.
“I'm very pleased about this successful acquisition of third-party funds. Korean Studies is a rare discipline with considerable appeal. Thanks to Professor Ahn, Goethe University has made a name for itself in this field beyond geographical borders," says Professor Bernhard Brüne, Goethe University's vice president for research. The funds, provided by the South Korean Ministry of Education, are intended to boost Korean Studies abroad (from a Korean perspective – “Empowering Korean Studies through innovative education, research and regional cooperation in Germany"). Apart from Goethe University, the University of Oxford was the only other European beneficiary awarded funding in 2021. The Frankfurt research project deals with ethnic and cultural diversity in Korea and in Korean populations in other countries. The title is: “Cultivating diversity: The global in Korea, Korea in the global".
Funding approval was preceded by two successfully completed projects financed with third-party funds within the Seed Programme for Korean Studies, which each ran for three years – from 2015 to 2021. Their purpose too was research and the further development of the Korean Studies programme. Within the framework of the Korean Studies Promotion Programme of the AKS, Korean Studies at Goethe University has now qualified for the follow-up project “Core University Programme for Korean Studies", which will last five years – from June 2021 to May 2026.
In this project, Korean Studies in Frankfurt, headed by Professor Ahn, is working closely together with Korean Studies at the University of Hamburg under Professor Yvonne Schulz Zinda and Korean Studies at the University of Bonn under Junior Professor Nadeschda Bachem. The aim, in particular, is to establish a comprehensive cross-university network between the institutes in order to further develop teaching, support for early career researchers, public relations work and joint research projects, and in so doing also boost Korean Studies within the Interdisciplinary Centre for East Asian Studies (IZO) at Goethe University.
In the area of teaching, new seminars are to be designed and implemented within the framework of the project and digital teaching expanded. To support young students, the intention is to jointly supervise their master's theses and doctoral dissertations. In addition, there are plans to work together more closely with secondary school pupils. In order to make Korean Studies more visible, special attention will be given to public relations work. Low-threshold offers should facilitate access to topics in the field of Korean Studies.
A total of nine further researchers are working on a broad spectrum of interdisciplinary, transnational and intersectional topics in the framework of the project “Cultivating diversity: The global in Korea, Korea in the global" led by Yonson Ahn. Migration, gender, art and media, among others, are featured topics.
Goethe University remains Hessen's only university with a focus on area studies in Asian studies. After other Asia-related institutes were transferred to Frankfurt in 2008, the Interdisciplinary Centre for East Asian Studies (IZO) was established at the university. Since then, Korean Studies has grown in significance both qualitatively and quantitatively. Students can start the Korean Studies programme without any previous knowledge. Apart from the language itself, the programme also covers the country's politics, culture and literature. Professor Yonson Ahn attributes its great popularity to the success of Korean film and pop culture, such as the boy band BTS or the films Parasites and Minari, which have won Oscars as well as prizes in Cannes. Graduates definitely have good future prospects: Frankfurt is home to the second largest number of Korean expatriates in Europe, while a large number of Korean companies, a Korean trade agency (KOTRA) and a Korean consulate are located in the city.
A photograph of Professor Yonson Ahn can be downloaded from: www.uni-frankfurt.de/103380737
Caption: Professor Yonson Ahn teaches Korean culture and society at Goethe University Frankfurt.
Professor Yonson Ahn
Phone: +49 (0)69 798-23769 / -22872
Fax: +49 (0)69 798-24969
Research team with Goethe University participation successfully proposes former quarry in Lower Saxony as Global Stratotype Section and Point
A team of scientists from Goethe University Frankfurt, the University of Warsaw, the State Authority for Mining, Energy and Geology (LBEG) in Hanover, and from other institutions world-wide, has found what researchers have been searching for worldwide for more than 20 years in Salzgitter-Salder: A geological formation that perfectly represents the transition from the Cretaceous Turonian to the Coniacian Age. The team has characterised the former limestone quarry so precisely that it is now considered a global reference point for the turn of the ages 89.4 million years ago. This was announced by the International Union of Geological Sciences, which awarded the stratotype profile the title "Global Stratotype Section and Point" (GSSP).
FRANKFURT/HANNOVER. The international team of geoscientists led by Prof. Silke Voigt from the Goethe University Frankfurt, Prof. Ireneusz Walaszczyk from the University of Warsaw and Dr André Bornemann from LBEG have thoroughly investigated 40 metres of the geological strata sequence in the former limestone quarry at Hasselberg. The researchers determined that this is only sequence in the transition between Turonian and Coniacian without gaps and it therefore represents a perfect rock sequence to serve geoscientists from all over the world as a reference for their research - a "Global Stratotype Section and Point (GSSP)" or, in the jargon of geosciences, a "golden nail".
Certain group of bivalve mollusks of the family Inoceramidae, first appeared in the Coniacian, and are found in large numbers in Salder. In Bed 46 of the quarry, the German-Polish scientific team found the oldest appearance of the Inoceramid species Cremnoceramus deformis erectus, which marks the time boundary. Careful studies also revealed other microfossils and a characteristic change in the ratio of the carbon isotopes 12C and 13C, a so-called negative anomaly in the carbon cycle.
"This means that variable geological sequences, such as marine shelf sediments in Mexico or the deep sea in the tropical Atlantic, can now be compared and classified in time," explains Prof. Silke Voigt. "This is important in order to be able to make an exact chronological classification even in the case of incomplete successions and ultimately to see, for example, what the climate was like at a certain time in the past in different places in the world."
Professor Ireneusz Walaszczyk says: "The sequence in Salzgitter-Salder prevails over other candidates, for example from the USA, India, Madagascar, New Zealand and Poland, because we have a perfect rock boundary sequence here over 40 metres, with a well-defined record of events which took place in this interval of geological time."
"The Zechstein Sea left behind massive salt layers in the North German Basin more than 250 million years ago," explains André Bornemann. "The rock layers deposited later exerted pressure on these salt layers, some of which bulged up into large salt domes, deforming younger layers in the process. Salder is located near such a salt dome, so that here the fossil-rich rock layers of the Cretaceous period are steeply upright, resulting in a wonderful profile that is very accessible for scientific investigations. That's why we at LBEG have designated this place as a geotope, and this is one of the most important geopoints of the Harz-Braunschweiger Land-Ostfalen UNESCO Global Geopark."
In the limestone quarry at Hasselberg near Salder in the north-east of the Salzgitter mountain range, limestone and marl used to be quarried for the cement industry and later for ore processing. Today, it is the location of a well-known biotope and geotope which is the property of the Stiftung Naturlandschaft (Natural Landscape Foundation) and established by the BUND regional association of Lower Saxony. While the care of the quarry site has been entrusted to the Salzgitter district group of BUND, the Harz-Braunschweiger Land-Ostfalen UNESCO Global Geopark looks after the geoscientific part of the quarry. The quarry is not freely accessible for nature conservation reasons, but guided walks are occasionally offered.
90 million years ago, in the second half of the Cretaceous, it was tropically warm on Earth: the ice-free poles ensured high sea levels, and Central Europe consisted of a cluster of islands. In the sea, ammonites developed a tremendous variety of forms, while dinosaurs reigned on land. The first flowering plants began to compete with horsetails and ferns. About 89.39 million years ago, the climate began to cool slightly, sea levels began sink, and a new period in Earth history, the Coniacian, replaced the Turonian.
Voigt S, Püttmann T, Mutterlose J, Bornemann A, Jarvis I, Pearce M, Walaszczyk, I (2021) Reassessment of the Salzgitter-Salder section as a potential stratotype for the Turonian–Coniacian Boundary: stable carbon isotopes and cyclostratigraphy constrained by nannofossils and palynology. Newsl Stratigr, 54/2, 209–228, https://doi.org/10.1127/nos/2020/0615
Walaszczyk, I., Čech, S., Crampton, J.S., Dubicka, Z., Ifrim, C., Jarvis, I., Kennedy, W.J., Lees, J.A., Lodowski, D., Pearce, M. Peryt, D., Sageman, B., Schiøler, P., Todes, J., Uličný, D., Voigt, S., Wiese, F., With contributions by, Linnert, C., Püttmann, T., and Toshimitsu, S. (2021) The Global Boundary Stratotype Section and Point (GSSP) for the base of the Coniacian Stage (Salzgitter-Salder, Germany) and its auxiliary sections (Słupia Nadbrzeżna, central Poland; Střeleč, Czech Republic; and El Rosario, NE Mexico). Episodes 2021; 44(2): 129-150l. https://doi.org/10.18814/epiiugs/2020/020072
Salzgitter-Salder: A perfect rock boundary sequence over 40 metres. (Photo: Silke Voigt, Goethe University Frankfurt)
GSSP in Salzgitter-Salder: Layer 46 marks the transition from the Cretaceous Turonian to the Coniacian Age. Photo and montage: Silke Voigt, Goethe University Frankfurt. Fossil: Walaszczyk et al. (2010)
Professor Silke Voigt
Goethe University Geocentre
Tel: +49 69 798-40190
Professor Ireneusz Piotr Walaszczyk
Institute for Historical and Regional Geology and Paleology
Researchers at Goethe University find small molecules as binding partners for genomic RNA of the coronavirus
Certain regions of the SARS-CoV-2 genome might be a suitable target for future drugs. This is what researchers at Goethe University, together with their collaborators in the international COVID-19-NMR consortium, have now discovered. With the help of dedicated substance libraries, they have identified several small molecules that bind to certain areas of the SARS-CoV-2 genome that are almost never altered by mutations.
FRANKFURT. When SARS-CoV-2 infects a cell, it introduces its RNA into it and re-programmes it in such a way that the cell first produces viral proteins and then whole viral particles. In the search for active substances against SARS-CoV-2, researchers have so far mostly concentrated on the viral proteins and on blocking them, since this promises to prevent, or at least slow down, replication. But attacking the viral genome, a long RNA molecule, might also stop or slow down viral replication.
The scientists in the COVID-19-NMR consortium, which is coordinated by Professor Harald Schwalbe from the Institute of Organic Chemistry and Chemical Biology at Goethe University, have now completed an important first step in the development of such a new class of SARS-CoV-2 drugs. They have identified 15 short segments of the SARS-CoV-2 genome that are very similar in various coronaviruses and are known to perform essential regulatory functions. In the course of 2020 too, these segments were very rarely affected by mutations.
The researchers let a substance library of 768 small, chemically simple molecules interact with the 15 RNA segments and analysed the result by means of NMR spectroscopy. In NMR spectroscopy, molecules are first labelled with special types of atoms (stable isotopes) and then exposed to a strong magnetic field. The atomic nuclei are excited by means of a short radio frequency pulse and emit a frequency spectrum, with the help of which it is possible to determine the RNA and protein structure and how and where small molecules bind.
This enabled the research team led by Professor Schwalbe to identify 69 small molecules that bound to 13 of the 15 RNA segments. Professor Harald Schwalbe: “Three of the molecules even bind specifically to just one RNA segment. Through this, we were able to show that the SARS-CoV-2 RNA is highly suitable as a potential target structure for drugs. In view of the large number of SARS-CoV-2 mutations, such conservative RNA segments, like the ones we've identified, are particularly interesting for developing potential inhibitors. And since the viral RNA accounts for up to two thirds of all RNA in an infected cell, we should be able to disrupt viral replication on a considerable scale by using suitable molecules." Against this background, Schwalbe continues, the researchers have now already started follow-up trials with readily available substances that are chemically similar to the binding partners from the substance library.
Publication: Sridhar Sreeramulu, Christian Richter, Hannes Berg, Maria A Wirtz Martin, Betül Ceylan, Tobias Matzel, Jennifer Adam, Nadide Altincekic, Kamal Azzaoui, Jasleen Kaur Bains, Marcel J.J. Blommers, Jan Ferner, Boris Fürtig, M. Göbel, J Tassilo Grün, Martin Hengesbach, Katharina F. Hohmann, Daniel Hymon, Bozana Knezic, Jason Martins, Klara R Mertinkus, Anna Niesteruk, Stephen A Peter, Dennis J Pyper, Nusrat S. Qureshi, Ute Scheffer, Andreas Schlundt, Robbin Schnieders, Elke Stirnal, Alexey Sudakov, Alix Tröster, Jennifer Vögele, Anna Wacker, Julia E Weigand, Julia Wirmer-Bartoschek, Jens Wöhnert, Harald Schwalbe: Exploring the druggability of conserved RNA regulatory elements in the SARS-CoV-2 genome, Angewandte Chemie International Edition, https://doi.org/10.1002/anie.202103693
the COVID-19-NMR consortium
Worldwide, over 40 working groups from 18 countries with a total of 230 scientists are conducting research within the COVID-19-NMR consortium. In Frankfurt, 45 doctoral and post-doctoral candidates have partly been working in two shifts per day, seven days a week, since the end of March 2020. www.covid19-nmr.de
Earlier press release: “Folding of SARS-CoV2 genome reveals drug targets – and preparation for “SARS-CoV3" https://tinygu.de/sEhyDScientific contact: