Amorphous Doped Indium Tin Oxide Thin‐Films by Atomic Layer Deposition.Insights into Their Structural, Electronic and Device Reliability

Thin semiconducting films of magnesium doped indium‐ and tin oxide are prepared by thermal atomic layer deposition (ALD). The metal oxide films are deposited at 200 °C from the precursors trimethylindium, tetrakis(dimethylamido)tin, bis(ethylcyclopentadienyl)magnesium and water as oxidant. These thin‐films are observed to be amorphous by electron microscopy and X‐ray diffraction. However, they exhibited a near‐range atomic order with correlation lengths of up to 10 Å, as demonstrated by high energy total scattering at grazing incidence employing synchrotron radiation. Even minor alterations in composition reveal a significant impact on the thin‐film transistor (TFT) device parameters, due to magnesium's high oxygen binding capability and its ability to inhibit the formation of oxygen vacancies, resulting in a decrease of free charge carriers in the material. Stability tests indicate a device degradation after storage in ambient conditions due to water adsorption on the surface, which could be reversed by an additional annealing step which qualify the films as robust. This studie demonstrate the possibility of employing minor amounts of high band gap oxides such as MgO to manipulate and control the electric behavior of the active channel layer performance in inorganic TFT devices

Tailoring superstructure units for improved oxygen redox activity in Li-rich layered oxide battery’s positive electrodes

The high-voltage oxygen redox activity of Li-rich layered oxides enables additional capacity beyond conventional transition metal (TM) redox contributions and drives the development of positive electrode active materials in secondary Li-based batteries. However, Li-rich layered oxides often face voltage decay during battery operation. In particular, although Li-rich positive electrode active materials with a high nickel content demonstrate improved voltage stability, they suffer from poor discharge capacity. Here, via physicochemical and electrochemical measurements, we investigate the correlation between oxygen redox activity and superstructure units in Li-rich layered oxides, specifically the fractions of LiMn₆ and Ni⁴⁺-stabilized LiNiMn₅ within the TM layer. We prove that an excess of LiNiMn₅ hinders the extraction/insertion of lithium ions during Li metal coin cell charging/discharging, resulting in incomplete oxygen redox activity at a cell potential of about 3.3 V. We also demonstrate that lithium content adjustment could be a beneficial approach to tailor the superstructure units. Indeed, we report an improved oxygen redox reversibility for an optimized Li-rich layered oxide with fewer LiNiMn5 units

Vor 50 Jahren: die erste drittelparitätische Senatssitzung an der Technischen Hochschule Darmstadt

Als 1966 das Hessische Hochschulgesetz (HHG) verabschiedet wurde, brachte die Hessische Landesregierung in Darmstadt einen Stein ins Rollen, der nach turbulenten Zeiten 1970 wieder abrupt zum Stehen kam: In § 6 des HHG wurden alle hessischen Hochschulen aufgefordert, sich eine Satzung zu geben. Diese sollte unter anderem die Zusammensetzung des Senats festlegen. Unter der Leitung von Rektor Dietrich Schultz bildete sich daraufhin an der damaligen TH eine Verfassungskommission, in der neben sieben Hochschullehrern auch ein Assistent und zwei Studierende mitwirkten. Es entstand ein 50-seitiger Entwurf, der dem Senat vorgelegt und nach umfassenden Diskussionen am 28. Juni 1967 verabschiedet wurde

Mutation induced infection waves in diseases like COVID-19

After more than 6 million deaths worldwide, the ongoing vaccination to conquer the COVID-19 disease is now competing with the emergence of increasingly contagious mutations, repeatedly supplanting earlier strains. Following the near-absence of historical examples of the long-time evolution of infectious diseases under similar circumstances, models are crucial to exemplify possible scenarios. Accordingly, in the present work we systematically generalize the popular susceptible-infected-recovered model to account for mutations leading to repeatedly occurring new strains, which we coarse grain based on tools from statistical mechanics to derive a model predicting the most likely outcomes. The model predicts that mutations can induce a super-exponential growth of infection numbers at early times, which self-amplify to giant infection waves which are caused by a positive feedback loop between infection numbers and mutations and lead to a simultaneous infection of the majority of the population. At later stages—if vaccination progresses too slowly—mutations can interrupt an ongoing decrease of infection numbers and can cause infection revivals which occur as single waves or even as whole wave trains featuring alternative periods of decreasing and increasing infection numbers. This panorama of possible mutation-induced scenarios should be tested in more detailed models to explore their concrete significance for specific infectious diseases. Further, our results might be useful for discussions regarding the importance of a release of vaccine-patents to reduce the risk of mutation-induced infection revivals but also to coordinate the release of measures following a downwards trend of infection numbers

Urban megaprojects, nation-state politics and regulatory capitalism in Central and Eastern Europe: The Belgrade Waterfront project

In this paper, we explore how state-led regulatory planning is utilised to push for delivery of an urban megaproject (UMP) in the specific context of post-socialist Central and Eastern Europe. Our focus is on the large-scale brownfield redevelopment project ‘Belgrade Waterfront’ under implementation in the Serbian capital, a joint venture between the Republic of Serbia and Abu Dhabi-based investor Eagle Hills. We show this UMP to be an extreme example of state-led regulatory intervention, characterised by lack of transparency and haste in decision-making processes, all of which serve to prioritise private investors’ interests in project delivery above the principles of representative democracy. Through analysis of legislative and planning documents, expert reports and media coverage from the period between 2012 and 2017, we explore the legislative mechanisms, contractual strategies and modes of governance involved in the project’s delivery. This provides two insights: first, it reveals that, in contrast with the active role of local governments in conceiving entrepreneurial strategies that is often assumed today, in the case of Belgrade Waterfront, the national government has instead played the decisive role; second, it shows how modifications to national law were instrumental in defining public interest, in enabling certain types of contracts to become technically legal, and in minimising risks for the private investor. We conclude by highlighting the need to further conceptualise nation-state politics and autocratic rule as driving forces of urban development processes

Enzyme-mediated radical polymerization for intracellular and solution reactions

Protein-mediated polymerization represents a rapidly expanding field at the interface between biotechnology and materials science, combining the catalytic function of proteins to the formation of polymeric structures under mild, biological conditions. More recently, intracellular polymerization has raised great interest because of its underlying potential to modify and functionalise living organisms. Through intracellular polymerisation, living cells' behaviour can be modulated to achieve cryostasis, tumour-specific targeting, or vaccine development. Furthermore, cells can be fixed to study or modify the bio-membranes, expose pathogenic peptides for T cell expression or constitute the base for regenerative medicine. Initial efforts to achieve intracellular polymerization focused on biorthogonal chemical reactions to avoid cell death or destruction, maintaining cell structures and functions unaltered. In this thesis, a further investigation of protein-mediated radical polymerization and its implementation into intracellular polymerization strategies in prokaryotic cells was conducted. Starting from previous knowledge about protein-mediated ATRP-like reactions in aqueous solutions, a novel application in intracellular polymerisation has been investigated. The well-known bacteria Escherichia coli BL21 has been chosen as a model organism for this purpose. Surprisingly, E. coli has demonstrated intrinsically pro-polymerisation properties, being able to autonomously polymerise a variety of monomers under anaerobic conditions and the presence of a classical water-soluble ATRP initiator. This new ability has been used to achieve a fast and effective cytoplasmatic polymerisation in living bacteria cells that show high biocompatibility and led to an unchanged proliferation capability of polymerised E. coli cells. The intrinsic ability of E. coli to autonomously trigger polymerisation reactions through ATRP initiators raised the question about the biocatalyst responsible for the activity. Through a series of molecular biology and proteomics techniques, the responsible catalyst has been revealed to be the enzyme succinyl ornithine transaminase. This discovery is the first example of a non-metal-based protein catalyst able to trigger an ATRP-like reaction in aqueous and complex media, showing a direct catalytic dehalogenation activity on alkyl halide initiators. On the topic of non-metal-based catalysts for radical polymerisation, another enzyme was found to have an unexpected catalytic activity. Glucose oxidase can indeed start a polymerisation reaction with a direct activity on certain monomer structures, producing free radicals that can start the polymerisation, without the need for initiators or metals. This finding enriches the knowledge of this versatile flavoprotein already used as a mediator for polymerisation reactions under mild and open-to-air conditions. Finally, some other open projects are briefly discussed, which can be linked to the main topics addressed in this thesis. Specifically, protein-mediate RAFT polymerisation in complex solutions derived from cellular lysis and the polymerization ability of yeast cells remains an open topic that requires further investigation. Together, these results further enriched the knowledge of protein-initiated polymerisation and intracellular polymerization. This work not only characterizes the catalytic machinery responsible for polymer formation in E. coli but also proposes new catalytic activity to well-known enzymes. Ultimately, this work deepens our understanding of enzyme-mediated polymerization and opens new avenues for the implementation of living cells as bio factories for next-generation materials

Terminologische Integration in akademischen Fachkulturen. Ein korpuspragmatischer Zugang

Der Beitrag beschäftigt sich damit, wie Termini in wissenschaftliche Texte eingeführt werden. Dabei gibt es grundsätzlich zwei Fälle: Erstens kann ein bestehender Terminus in einen Text eingeführt werden; zweitens kann ein Terminus neu eingeführt und im Fachdiskurs vorgeschlagen werden. In diesem Beitrag wird untersuchen wir den ersten, wesentlich häufigeren Fall. Unser Fokus liegt dabei auf den Textroutinen der Implementierung von Termini - bspw. unterschiedlichen Referenzierungspraktiken, Relevanzmarkierungen, Formen der Differenzierung, Strukturierung, Einordnung und Abgrenzung sowie der Kontextualisierung. Wir beleuchten Gemeinsamkeiten und Unterschiede solcher Fälle in der Breite der akademischen Fachkulturen

Sprachmittlung in der Projektarbeit im universitären Herkunftssprachenunterricht Polnisch

In der vorliegenden Arbeit wurde im Rahmen einer qualitativen Studie untersucht, wie Studierende mit der Herkunftssprache Polnisch bei einer Sprachmittlungshandlung im Rahmen einer Projektarbeit vorgehen, welche spezifischen Sprachmittlungsprozesse sich daraus ableiten lassen und wie diese in der Projektarbeit zu verorten sind. Durch die Methodentriangulation von Videografie, teilnehmender Beobachtung und Leitfadeninterviews konnten Daten gewonnen werden, die einen tiefen Einblick in das Vorgehen der herkunftssprachlichen Studierenden und ihren Einsatz von Sprachmittlungsprozessen in einer als Projektarbeit konzipierten Sprachmittlungshandlung gewähren. Es konnte gezeigt werden, dass die Sprachmittlungshandlung in der Projektarbeit ein komplexer und zyklischer Prozess ist, der von dem Projektziel, den Projektteilnehmenden und dem festgelegten Projektprodukt abhängt, und die identifizierten Sprachmittlungsprozesse in der gesamten Projektarbeit jedoch mit unterschiedlicher Häufigkeit auftreten

Breaking it down, to build it back up: Attacks and Defenses for RPKI

The Border Gateway Protocol (BGP) is the glue that holds the Internet together and enables packets to reach their destinations. However, BGP is not secure by design. It is vulnerable to hijacking attacks and route leaks, and the community has tried for decades to find a solution for this design error. The Resource Public Key Infrastructure (RPKI) has emerged as the only currently feasible solution to BGP's woes. It is an intuitive, flexible infrastructure that allows any BGP security protocol that relies on distributed, cryptographically verifiable data, to get incorporated and effectively deployed across BGP routers. RPKI already covers over 50% of network prefixes and is deployed by at least 27% of networks in the world. It has already proven its benefits over the past few years due to many BGP hijacks, which went unnoticed by those deploying RPKI, but caused severe consequences for those who didn't. RPKI has proven itself so successful, that the Federal Communications Commission (FCC) published a recommendation on routing security, where they suggested mandating the use of RPKI for all major ISP providers in the US. However, not all that glitters is gold. While RPKI is an excellent approach to solving the security issues of BGP, it is not perfect. In this work, the author evaluates the security of the RPKI ecosystem as a whole, and that of all RPKI software components individually. The author discovers a range of attacks that lead to the silent downgrade of RPKI protection, or the Denial-of-Service (DoS) of RPKI components, and evaluates current RPKI deployment practices only to discover trends that are concerning when extrapolated to full RPKI deployment. Finally, this work also provides the first attempt to mitigate all above mentioned RPKI issues through a distributed infrastructure that enhances RPKI component security and efficiency, and is backwards compatible with the current RPKI environment. This thesis is based on work published in 6 full papers and 2 posters in international academic conferences. This work resulted in the discovery of 18 vulnerabilities in RPKI code, and the issuance of 5 Common Vulnerabilities and Exposures (CVEs)

PUMA, antiProton unstable matter annihilation

PUMA, antiProton Unstable Matter Annihilation, is a nuclear-physics experiment at CERN aiming at probing the surface properties of stable and rare isotopes by use of low-energy antiprotons. Low-energy antiprotons offer a very unique sensitivity to the neutron and proton densities at the annihilation site, i.e. in the tail of the nuclear density. Today, no facility provides a collider of low-energy radioactive ions and low-energy antiprotons: while not being a collider experiment, PUMA aims at transporting one billion antiprotons from ELENA, the Extra-Low-ENergy Antiproton ring, to ISOLDE, the rare-isotope beam facility of CERN. PUMA will enable the capture of low-energy antiprotons by short-lived nuclei and the measurement of the emitted radiations. In this way, PUMA will give access to the so-far largely unexplored isospin composition of the nuclear-radial-density tail of radioactive nuclei. The motivations, concept and current status of the PUMA experiment are presented