Starker Start ins Studium: Qualitätspakt Lehre
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Professionalization of service-learning in higher education – an academic development approach
(2018)
In an attempt to professionalize service-learning in higher education, teachers and their teaching skills are considered a determining factor and require particular attention. To promote the teaching skills necessary for service-learning courses, an academic development approach addressing these specific requirements has been implemented at Goethe University Frankfurt as part of the academic development program for teaching staff. This article presents the particularities of this approach and illustrates one of its central elements, i.e., the concept of a workshop on planning service-learning courses. Both practical and research implications are discussed.
PELDOR (pulse electron-electron double resonance) is an established method to study intramolecular distances and can give evidence for conformational changes and flexibilities. However, it can also be used to study intermolecular interactions as for example oligerimization. Here, we used PELDOR to study the ‘end-to-end’ stacking of small double stranded (ds)RNAs. For this study, the dsRNA molecules were only singly labelled with the spin label TPA to avoid multi-spin effects and to measure only the intermolecular stacking interactions. It can be shown that small dsRNAs tend to assemble to rod-like structures due to π-π-interactions between the base pairs at the end of the strands. On the one hand, these interactions can influence or complicate measurements aimed at the determining of the structure and dynamics of the dsRNA molecule itself. On the other hand, it can be interesting to study such intermolecular stacking interactions in more detail, as for example their dependence on ion concentration. We quantitatively determined the stacking probability as a function of the monovalent NaCl salt and the dsRNA concentration. From this data the dissociation constant Kd was deduced and found to depend on the ratio between the NaCl salt and dsRNA concentrations. Additionally, the distances and distance distributions obtained predict a model for the stacking geometry of dsRNAs. Introducing a nucleotide overhangs at one end of the dsRNA molecule restricts the stacking to the other end, leading only to dimer formations. Introducing such an overhang at both ends of the dsRNA molecule fully suppresses stacking, as we could demonstrate by PELDOR experiments quantitatively.
A new method for size resolved chemical analysis of nucleation mode aerosol particles (size range from ~10 to ~30 nm) is presented. The Thermal Desorption Differential Mobility Analyzer (TD-DMA) uses an online, discontinuous principle. The particles are charged, a specific size is selected by differential mobility analysis and they are collected on a filament by electrostatic precipitation. Subsequently, the sampled mass is evaporated in a clean carrier gas and analyzed by a chemical ionization mass spectrometer. Gas phase measurements are performed with the same mass spectrometer during the sampling of particles. The characterization shows reproducible results, with a particle size resolution of 1.19 and the transmission efficiency for 15 nm particles being slightly above 50 %. The signal from the evaporation of a test substance can be detected starting from 0.01 ng and shows a linear response in the mass spectrometer. Instrument operation in the range of pg/m3 is demonstrated by an example measurement of 15 nm particles produced by nucleation from dimethylamine, sulfuric acid and water.
A new method for size-resolved chemical analysis of nucleation mode aerosol particles (size range from ∼10 to ∼30 nm) is presented. The Thermal Desorption Differential Mobility Analyzer (TD-DMA) uses an online, discontinuous principle. The particles are charged, a specific size is selected by differential mobility analysis and they are collected on a filament by electrostatic precipitation. Subsequently, the sampled mass is evaporated in a clean carrier gas and analyzed by a chemical ionization mass spectrometer. Gas-phase measurements are performed with the same mass spectrometer during the sampling of particles. The characterization shows reproducible results, with a particle size resolution of 1.19 and the transmission efficiency for 15 nm particles being slightly above 50 %. The signal from the evaporation of a test substance can be detected starting from 0.01 ng and shows a linear response in the mass spectrometer. Instrument operation in the range of pg m−3 is demonstrated by an example measurement of 15 nm particles produced by nucleation from dimethylamine, sulfuric acid and water.
Introduction Current: evidence suggests that the loss of mechanoreceptors after anterior cruciate ligament (ACL) tears might be compensated by increased cortical motor planning. This occupation of cerebral resources may limit the potential to quickly adapt movements to unforeseen external stimuli in the athletic environment. To date, studies investigating such neural alterations during movement focused on simple, anticipated tasks with low ecological validity. This trial, therefore, aims to investigate the cortical and biomechanical processes associated with more sport-related and injury-related movements in ACL-reconstructed individuals.
Methods and analysis: ACL-reconstructed participants and uninjured controls will perform repetitive countermovement jumps with single leg landings. Two different conditions are to be completed: anticipated (n=35) versus unanticipated (n=35) successful landings. Under the anticipated condition, participants receive the visual information depicting the requested landing leg prior to the jump. In the unanticipated condition, this information will be provided only about 400 msec prior to landing. Neural correlates of motor planning will be measured using electroencephalography. In detail, movement-related cortical potentials, frequency spectral power and functional connectivity will be assessed. Biomechanical landing quality will be captured via a capacitive force plate. Calculated parameters encompass time to stabilisation, vertical peak ground reaction force, and centre of pressure path length. Potential systematic differences between ACL-reconstructed individuals and controls will be identified in dependence of jumping condition (anticipated/ unanticipated, injured/uninjured leg and controls) by using interference statistics. Potential associations between the cortical and biomechanical measures will be calculated by means of correlation analysis. In case of statistical significance (α<0.05.) further confounders (cofactors) will be considered.
Ethics and dissemination: The independent Ethics Committee of the University of Frankfurt (Faculty of Psychology and Sports Sciences) approved the study. Publications in peer-reviewed journals are planned. The findings will be presented at scientific conferences.
Trial status: At the time of submission of this manuscript, recruitment is ongoing.
Trial registration number: NCT03336060; Pre-results.