Impact of substrate topology, chemical stimuli and Janus nanoparticles on cellular properties

Cellular behavior is influenced by many biochemical but also physical factors in the direct cellular environment. Thereby, cells not only react to external cues, the interaction between cells and their environment is also dependent on the properties of the cell itself. The endocytosis of nanoparticles for example depends on the intermolecular forces between plasma membrane and particle as well as on the mechanical properties of the membrane. In the first part of this thesis I focus on the interaction between inorganic Janus nanoparticles, a new type of nanomaterials, which possess amphiphilic properties, and model membranes. In coarse grain simulations it has been demostrated that incubation of membranes with these particles lead either to pore formation in the lipid bilayer or to tubulation and vesiculation by long-range attractive interaction between particles bound to the membrane. Conducting surface plasmon resonance spectroscopy experiments I show that the binding energy of the used inorganic Janus particles to a solid supported monolayer could be sufficient to induce tubulation of tension-free membranes but is to small to provide the energy necessary to form a vesicle. This result is confirmed by fluorescence microscopic examination of giant unilamellar vesicles serving as a model system for the plasmamembrane, which were treated with Janus particles. Vesicles incubated with Janus particles show inwards directed membrane tubes, while incubation of vesicles with isotropic control particles had no effect on the membrane or could be attributed to an osmotic gradient. However, uptake experiments into living cells and cytotoxicity assays show no obvious difference between spherical particles and Janus particles, which hints for a negligible contribution of nanoparticle-induced tubulation or vesiculation to cellular uptake of nanoparticles and cytotoxicity. On the one hand mechanical properties of the cell influence the interaction between the cell and its environment. On the other hand, mechanical properties of cells change in response to environmental cues. Therefore, in the next part, atomic force microscopy-based microrheology is used to measure frequency-dependent mechanical properties of cells in different conditions. Fixation of cells with different chemical fixatives and transformation of epithelial cells to mesenchymal cells lead to more solid-like mechanical properties, while interaction with the actin cytoskeleton lead to more fluid-like properties. A comparison between malignant cells and non-malignant cells shows that malignant cells are more fluid-like compared to their non-malignant counterparts. Furthermore, the influence of substrate topology on cellular mechanics and cytoskeletal arrangement is examined. Changing physical properties of the substrate such as stiffness or topography has been shown to affect plenty of cellular processes like migration, proliferation, morphology or differentiation. Here, I investigate the impact of porous substrates on cellular morphology, cytoskeletal organization and elasticity in the context of confluent epithelial monolayers. I found that cells eventually self-organize to match the geometry of the pore pattern and remodel their actin cytoskeleton to reinforce their adhesion zone. Cells fluidize with increasing pore size up to 2 µm but eventually become stiffer if grown on very large pores up to 5 µm. The adhesion of cells to substrates is further researched by application of metal-induced energy transfer fluorescence lifetime imaging, which is used for the first time for this purpose. The fluorescence lifetime of a fluorophore in proximity to a metal layer is a function of the distance between fluorophore and metal layer. Applying a quantitative model of this interaction facilitates locating the fluorophore with nanometer precision in the axial direction up to 200 nm above the metal layer. By staining of the plasmamembrane I was able to image to basal membrane of three different cell lines and follow spreading of cells with high axial resolution. The introduced method is not restricted to measurement of cell/substrate distance and can be used for applications, which necessitate axial nanometer resolution in a range up to 200 nm

Measuring Luttinger Liquid Correlations from Charge Fluctuations in a Nanoscale Structure

We suggest an experiment to study Luttinger liquid behavior in a one-dimensional nanostructure, avoiding the usual complications associated with transport measurements. The proposed setup consists of a quantum box, biased by a gate voltage, and side-coupled to a quantum wire by a point contact. Close to the degeneracy points of the Coulomb blockaded box, and in the presence of a magnetic field sufficiently strong to spin polarize the electrons, the setup can be described as a Luttinger liquid interacting with an effective Kondo impurity. Using exact nonperturbative techniques we predict that the differential capacitance of the box will exhibit distinctive Luttinger liquid scaling with temperature and gate voltage.Comment: REVTeX, 4 pages, 1 figure included. Final version, two references adde

Professionalisierung von Lehrkräften für Digitalität und Inklusion

Durch verändertes Lehren und Lernen in einer Kultur der Digitalität und steigende Heterogenität im Zuge inklusiver Schulentwicklungen stehen Lehrkräfte vor der Herausforderung, Unterricht mit und über digitale Medien in inklusiven Lehr-Lernkontexten gewinnbringend zu gestalten. Bei der professionellen Initiierung von inklusiven Medienbildungsprozessen kommt Lehrkräften eine Schlüsselaufgabe zu. Universitäre Lehr- und Lernkonzepte können angehende Lehrkräfte auf die Gestaltung, Durchführung und Reflexion digital-inklusiver Lehr- und Lernsituationen vorbereiten. Konzepte, die zu einer systematischen Qualifizierung angehender Lehrkräfte in den Kompetenzbereichen im Kontext von Digitalität und Inklusion beitragen, sind bislang jedoch eher eine Ausnahme. Folglich stellt sich die Frage, wie universitäre Lehrveranstaltungen im Rahmen der Lehrkräftebildung gestaltet werden können, um angehende Lehrkräfte in diesem Bereich zu professionalisieren. Im vorliegenden Beitrag wird zunächst herausgearbeitet, welche Lehrkräftekompetenzen im Rahmen von Digitalität und Inklusion bedeutsam sind. Die Grundlage dafür bilden Publikationen zu Rahmenmodellen und Kompetenzkatalogen aus medienpädagogischen und inklusionsbezogenen Diskursen, deren zentrale Aussagen mittels eines narrativen Reviews in einem Modell zusammengeführt werden, das aus sieben Kompetenzbereichen besteht. Im Anschluss wird ein universitäres Seminarkonzept vorgestellt, das an vier Kompetenzbereichen dieser Modellierung ausgerichtet ist. In der Lehrveranstaltung erstellen Studierende des Lehramts an Grundschulen sowie des Lehramts für Sonderpädagogik in interdisziplinär zusammengesetzten Kleingruppen digitale Bilderbücher, die im Beitrag exemplarisch vorgestellt werden. Abschließend wird das entwickelte Modell sowie die darauf aufbauende Konzeption des Seminarangebots diskutiert und mit Blick auf ihre Bedeutung für die Professionalisierung von (angehenden) Lehrkräften für einen digital-inklusiven Unterricht reflektiert.   Abstract Due to changes in teaching and learning in a culture of digitality and increasing heterogeneity, resulting from recent inclusive school developments, teachers face the challenge of designing lessons with and about digital media in an inclusive context. Teachers play a key role in initiating inclusive media education processes as professionals. University teaching and learning concepts can prepare future teachers for the design, implementation and reflection of digital and inclusive teaching and learning situations. However, concepts that contribute to a systematic qualification of future teachers in the areas of competence regarding digitality and inclusion have so far been the exception rather than the rule. Consequently, the question arises as to how university courses can be designed within the framework of teacher training to professionalize future teachers in this area. In this article, the relevant teacher competencies in the context of digitality and inclusion are first outlined. The basis for this is formed by publications on framework models and competency catalogs from media-educational and inclusion-related discourses, whose central statements are combined in a model containing seven areas of competence through a narrative review. Subsequently, a university course concept will be presented, which is based on four of the seven aforementioned areas of competence. In this course, future primary school and special education teachers together, in small interdisciplinary groups, create digital picture books – some of which are presented as examples in this article. Finally, the developed model, as well as the course concept, are discussed and reflected upon regarding their contribution to the professionalization of (future) teachers for digital-inclusive teaching

Late Pleistocene Glacial Geology of the Hope-Waiau Valley System in North Canterbury, New Zealand

This thesis presents stratigraphic, sedimentological and geochronological results from valley fill and glacial moraines of the Hope-Waiau Valleys in North Canterbury, New Zealand. The findings demonstrate that a substantial portion of the modern valley fill comprises in-situ sedimentary sequences that were deposited during the penultimate glaciation (OIS 6), the last interglacial (OIS 5) and during the mid-late last glacial cycle (OIS 3/2). The sediments survived at low elevations in the valley floor despite overriding by later glacial advances. Sedimentologically, the fill indicates deposition in an ice marginal zone and consists of paraglacial/distal-proglacial aggradation gravels and ice-proximal/marginal-subglacial sediments. Deposition during glacial advance phases was characterized by the sedimentation of outwash gravels and small push moraines while glacial retreat phases are dominated by glaciolacustrine deposits which are frequently interbedded with debris flow diamictons. The overall depositional arrangement indicates that glacial retreat from the lower valley portion occurred via large scale ice stagnation. Results from infra-red stimulated luminescence (IRSL) dating gives evidence for five large aggradation and degradation phases in the Hope-Waiau Valleys over the last 200 ka. Combined with surface exposure dating (SED) of moraines the geochronological results indicate that glacial advances during OIS 6 were substantially larger in both ice extent and ice volume than during OIS 4-2. The last glacial maximum (LGM) ice advance occurred prior to 20.5 ka and glacial retreat from extended ice positions began by ~18 ka BP. A late glacial re-advance (Lewis Pass advance) occurred at ~13 ka BP and is probably associated with a regional cooling event correlated to the Antarctic Cold Reversal (ACR). The findings from the Hope-Waiau Valleys were integrated into a model for glaciations in the Southern Alps which uses data from a snow mass balance model to analyse the sensitivity of glacial accumulation to temperature forcing. Model results indicate that in the central hyperhumid sector of the Southern Alps ice would expand rapidly with minor cooling (2-4℃) suggesting that full glaciation could be generated with little thermal forcing. Some Quaternary glacial advances in the Southern Alps may have been triggered by regional climate phenomena (e.g. changes in ENSO mode) rather than requiring a thermal trigger from the Northern Hemisphere

Late Glacial to Holocene dune development at southern Krakower See

The site at the southern shore of Krakower See shows the Quaternary geology of the surrounding area. The local Quaternary sequence comprises a thickness of 50–100m of Quaternary deposits while the surface morphology is dominated by the ice marginal position of the Pomeranian moraine, which passes through the area. The bathymetry of the lake basin of Krakower See indicates a predominant genesis by glaciofluvial erosion in combination with glacial exaration. Past research in this area has focussed on the reconstruction of Pleniglacial to Holocene environmental changes, including lake-level fluctuations, aeolian dynamics, and pedological processes and their modification by anthropogenic land use

Distribution and timing of Holocene and late Pleistocene glacier fluctuations in western Mongolia

Despite being a key location for paleoglaciological research in north-central Asia, with the largest number of modern and Pleistocene glaciers, and in the transition zone between the humid Russian Altai and dry Gobi Altai, little is known about the precise extent and timing of Holocene and late Pleistocene glaciations in western Mongolia. Here we present detailed information on the distribution of modern and late Holocene glaciers, and new results addressing the geomorphological differentiation and numerical dating (by optically stimulated luminescence, OSL) of Pleistocene glacial sequences in these areas. For the Mongolian Altai, geochronological results suggest large ice advances correlative to marine isotope stages (MIS) 4 and 2. This is in contrast to results from the Khangai mountains, central Mongolia, showing that significant ice advances additionally occurred during MIS3. During the Pleistocene, glacial equilibrium-line altitudes (ELAs) were �500 to >1000m lower in the more humid portion of the Russian and western Mongolian Altai, compared to 300–600m in the drier ranges of the eastern Mongolian Altai. Pleistocene ELAs in the Khangai mountains were depressed by 700–1000 m, suggesting more humid conditions at times of major glaciation than in the eastern Mongolian Altai. This paleo-ELA pattern reveals that the precipitation gradient from the drier to the more humid regions was more pronounced during glacial times than at present

Digital lesen und erzählen. Eine Projektwoche für den inklusiven Anfangsunterricht

Das Digital Storytelling bietet Schüler:innen im inklusiven Anfangsunterricht vielfältige Möglichkeiten der Teilhabe am Unterricht. Lesen Sie in diesem Beitrag, wie die Kinder eine digitale Geschichte auf unterschiedliche Art rezipieren und weitererzählen können