Search

Observations of OH airglow provide an important opportunity for tracing the variability of the mesosphere lower thermosphere (MLT) on time scales from minutes to decades. While OH rotational temperatures are derived on a routine basis, precise absolute radiances of OH airglow are usually only available from satellite missions or astronomical sites. In order to provide traceability also to the ground-based Network for the Detection of Mesosphere Change (NDMC) a new calibration approach was developed and applied to observations performed at UFS “Schneefernerhaus” (11.0°E, 47.0° N).Both OH temperatures and OH radiances show a positive correlation with solar activity (i.e. with F10.7cm). However, the increase of MLT temperatures during the maximum of solar cycle 24 was of similar magnitude as reported for previous cycles, despite the solar forcing being much weaker resulting in a strong relative forcing term of approximately 6K/100sfu. This suggests the presence of an indirect dynamical feedback mechanism rather than a direct forcing and there are indications for atmospheric solar tides playing an important role in this coupling.The high data quality allows for sophisticated analyses in the spectral range from days to years. These analyses reveal pronounced oscillations in the period range of 30 to 180 days between 2011 and 2015, followed by rather quite years until these oscillations reemerge again in 2020. The observations are confirmed by data from other NDMC sites. However, the physical nature of these oscillations and their apparent link to solar activity is not yet understood and open for discussion., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

In November 2022 the OASIS measurement system (Observations of Airglow with Spectrometer and Imager Systems) for airglow observations was set up right next to ESO's Very Large Telescope (VLT) in Chile. It aims for observing OH nightglow with high temporal resolution in order to investigate natural hazards emitting waves (e.g. tsunamis, earthquakes, storms). Furthermore, general middle atmospheric dynamics are studied in greater detail above the Andes region, among others to develop precise methods for providing valuable near-real time data about the airglow variability for the astronomic observation scheduling of the VLT. The OASIS system consists of three airglow instruments, one spectrometer with a pan-tilt mechanism to observe selected events at any direction on the nightsky on demand, and two imager systems, an allsky camera and a narrower field-of-view camera. All three instruments have a high temporal resolution of (15s, 2s, and 1.5s, respectively) and observe the short-wave infrared part of OH nightglow around 1.5µm to 1.6µm. The good observation conditions at the astronomic site with clear sky conditions throughout the entire year give a very good data coverage allowing for unique analyses on a statistical basis as well as on specific case studies e.g. of waves emitted by natural hazard events propagating up to the mesosphere and lower thermosphere. We present the OASIS measurement system, its mission objectives, and first results from the first nine months of observations concerning general gravity wave activity above the Andes, stunning gravity wave events, and extraordinary variations of airglow intensity., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The cortisol awakening response (CAR), the marked increase in cortisol secretion over the first 30–45 min after morning awakening, has been related to a wide range of psychosocial, physical and mental health parameters, making it a key variable for psychoneuroendocrinological research. The CAR is typically assessed from self-collection of saliva samples within the domestic setting. While this confers ecological validity, it lacks direct researcher oversight which can be problematic as the validity of CAR measurement critically relies on participants closely following a timed sampling schedule, beginning with the moment of awakening. Researchers assessing the CAR thus need to take important steps to maximize and monitor saliva sampling accuracy as well as consider a range of other relevant methodological factors. To promote best practice of future research in this field, the International Society of Psychoneuroendocrinology initiated an expert panel charged with (i) summarizing relevant evidence and collective experience on methodological factors affecting CAR assessment and (ii) formulating clear consensus guidelines for future research. The present report summarizes the results of this undertaking. Consensus guidelines are presented on central aspects of CAR assessment, including objective control of sampling accuracy/adherence, participant instructions, covariate accounting, sampling protocols, quantification strategies as well as reporting and interpreting of CAR data. Meeting these methodological standards in future research will create more powerful research designs, thus yielding more reliable and reproducible results and helping to further advance understanding in this evolving field of research.

Creating filled or hollow channels within 3D tissues has become increasingly important in tissue engineering. Channels can serve as vasculature enhancing medium perfusion or as conduits for nerve regeneration. The 3D biofabrication seems to be a promising method to generate these structures within 3D constructs layer-by-layer. In this study, geometry and interface of bioprinted channels were investigated with micro-computed tomography and fluorescent imaging. In filament printing, size and shape of printed channels are influenced by their orientation, which was analyzed by printing horizontally and vertically aligned channels, and by the ink, which was evaluated by comparing channels printed with an alginate-gelatin hydrogel or with an emulsion. The influence of geometry and cell-embedding in the hydrogel on feature size and shape was investigated by printing more complex channels. The generation of hollow channels, induced through leaching of a support phase, was monitored over time. Horizontally aligned channels provided 16× smaller cross-sectional areas than channels in vertical orientation. The smallest feature size of hydrogel filaments was twice as large compared to emulsion filaments. Feature size and shape depended on the geometry but did not alter when living cells were embedded. With that knowledge, channels can be consciously tailored to the particular needs

Three-dimensional (3-D) bioprinting is the layer-by-layer deposition of biological material with the aim of achieving stable 3-D constructs for application in tissue engineering. It is a powerful tool for the spa- tially directed placement of multiple materials and/or cells within the 3-D sample. Encapsulated cells are protected by the bioink during the printing process. Very few materials are available that fulfill require- ments for bioprinting as well as provide adequate properties for cell encapsulation during and after the printing process. A hydrogel composite including alginate and gelatin precursors was tuned with differ- ent concentrations of hydroxyapatite (HA) and characterized in terms of rheology, swelling behavior and mechanical properties to assess the versatility of the system. Instantaneous as well as long-term struc- tural integrity of the printed hydrogel was achieved with a two-step mechanism combining the thermo- sensitive properties of gelatin with chemical crosslinking of alginate. Novel syringe tip heaters were developed for improved temperature control of the bioink to avoid clogging. Human mesenchymal stem cells mixed into the hydrogel precursor survived the printing process and showed high cell viability of 85% living cells after 3 days of subsequent in vitro culture. HA enabled the visualization of the printed structures with micro-computed tomography. The inclusion of HA also favors the use of the bioink for bone tissue engineering applications. By adding factors other than HA, the composite could be used as a bioink for applications in drug delivery, microsphere deposition or soft tissue engineering.

Defining the most adequate architecture of a bone substitute scaffold is a topic that has received much attention over the last 40 years. However, contradictory results exist on the effect of grain size and microporosity. Therefore, the aim of this study was to determine the effect of these two factors on the in vivo behaviour of ß-tricalcium phosphate (ß-TCP) scaffolds. For that purpose, ß-TCP scaffolds were produced with roughly the same macropore size (˜ 150 µm), and porosity (˜ 80 %), but two levels of microporosity (low: 10 % / high: ˜ 25 %) and grain size (small: 1.3 µm /large: ˜ 3.3 µm). The sample architecture was characterised extensively using materialography, Hg porosimetry, micro-computed tomography (µCT), and nitrogen adsorption. The scaffolds were implanted for 2, 4 and 8 weeks in a cylindrical 5-wall cancellous bone defect in sheep. The histological, histomorphometrical and µCT analysis of the samples revealed that all four scaffold types were almost completely resorbed within 8 weeks and replaced by new bone. Despite the three-fold difference in microporosity and grain size, very few biological differences were observed. The only significant effect at p