83 results on '"Sonnleitner M"'
Search Results
2. Ultrasensitive Microscopy of the Plasma Membrane of Living Cells
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Schütz, G. J., Sonnleitner, M., and Schindler, H.
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- 2001
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3. Mixing of a Model Substrate in a Scale-down Laboratory Digester and Processing with a Computational Fluid Dynamics Model
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FOSCA CONTI, Wiedemannn, L., Saidi, A., Sonnleitner, M., and Goldbrunner, M.
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Biomass - Abstract
Energy demand for mixing of biomass digesters is a crucial parameter in design and operation of biogas plants. Optimization of flow characteristics in the fermentation process is usually focused on the stirrers where their placement, shape and number, as well as their rotational speed and switching sequence are all important decision variables for overall energy efficiency planning. Digester stirring was analyzed in a cylindrical transparent physical digester model located in our laboratories in Ingolstadt. Real biomass was substituted with a chemical substrate based on cellulose exhibiting transparency, physico-chemical stability, ease of use and rheological behavior comparable to real biomass. Different mixing regimes were configured using propellers and paddle stirrers located in various positions. The motion of the liquid within the tank was investigated with optical and acoustic techniques in a non-invasive way. The software tool StarCCM + was used to develop a computational fluid dynamics (CFD) model to simulate the mixing process and the flow patterns within the digester. The results of the laboratory experiments were used to validate the CFD model., Proceedings of the 26th European Biomass Conference and Exhibition, 14-17 May 2018, Copenhagen, Denmark, pp. 811-815
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- 2018
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4. How to measure flexibility – Performance indicators for demand driven power generation from biogas plants
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Dotzauer, M., Pfeiffer, D., Lauer, M., Pohl, M., Mauky, E., Bär, K., Sonnleitner, M., Zörner, W., Hudde, J., Schwarz, B., Faßauer, B., Dahmen, M., Rieke, C., Herbert, J., Thrän, Daniela, Dotzauer, M., Pfeiffer, D., Lauer, M., Pohl, M., Mauky, E., Bär, K., Sonnleitner, M., Zörner, W., Hudde, J., Schwarz, B., Faßauer, B., Dahmen, M., Rieke, C., Herbert, J., and Thrän, Daniela
- Abstract
Flexible power provision from biogas can significantly contribute to energy systems with high shares of renewables. However, the characteristics and demands for this flexibility are not clearly defined or measured. In this paper eight indicators are defined to shape “flexibility” and perform a downstream investigation of eight research projects focusing on flexible energy provision of biogas plants. The indicators are structured in three dimensions (1) velocity (ramps) by which the system can be modulated, (2) power range (bandwidth) and (3) duration for specific load conditions. Based on these indicators bottlenecks for the flexibility potential were identified. One crucial result shows that short-term flexibility of biogas plants is mainly driven by properties of the combined heat and power unit (velocity and bandwidth). The long-term flexibility depends mainly on gas storage, mode of operation and ability for modulation of the target gas production.
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- 2018
5. Model-based assessment of partially upgraded biogas and the decentralized utilization for mobility in agriculture
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Saidi, A., FOSCA CONTI, Sonnleitner, M., and Goldbrunner, M.
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decentralized ,biogas ,modeling ,Biomass ,biogas, upgrading, decentralized, fuel, combustion, modeling ,fuel ,upgrading ,combustion - Abstract
Since almost 100 % of worldwide farm machinery is operated on fossil fuels, the agricultural sector shows a great demand for the implementation of environmental power train concepts. Taking the general immediate vicinity between biogas plants and farms into account, a promising approach is given by the decentralized utilization of biogas as fuel for agricultural vehicles. The aim of the study is to provide a model based assessment system of the production, storage, and consumption of partially upgraded biogas as tractor fuel. In contrast to common upgrading systems, the methane enrichment is reduced to a certain extent enabling a suitable combustion process operating the vehicle engine. Through extensive market research of commercially available technologies, upgrading, storage and fueling concepts have been developed and evaluated for technical and economic feasibility. The evaluation includes model based investigations of several processes for the upgrading and storage system. An overall model summarizing the process-related design, peripheral sub-processes, safety requirements and economic analysis, conceived as an evaluation tool represents the key purpose of the research project. The following explanations are focused on the modeling approach for the methane enrichment process., Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 1358-1361
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- 2017
6. Synthesizing variable particle interaction potentials via spectrally shaped spatially coherent illumination
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Holzmann, D, primary, Sonnleitner, M, additional, and Ritsch, H, additional
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- 2018
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7. Microstructural Characterization of Ultra-High Strength Martensitic Steels
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Esterl, R., primary, Sonnleitner, M., additional, Stadler, M., additional, Wölger, G., additional, and Schnitzer, R., additional
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- 2018
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8. Imaging individual molecules by two-photon excitation
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Sonnleitner, M, Schütz, G.J, and Schmidt, Th
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- 1999
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9. Optimized Operation of Flexible Biogas Plants
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Braun, T., Dotzauer, M., Goldbrunner, M., Häring, G., Hanby, V., Krautz, A., Pfeiffer, D., Sonnleitner, M., and Zörner, W.
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Biomass - Abstract
The Federal Ministry for the Environment, Nature Conservation and Nuclear Safety in Germany has been giving biogas power a key-role as balancing electricity. It can supply power only when needed to balance intermittent renewable energy sources such as wind or photovoltaic electricity. But currently conventional biogas plants are operated continuously and at a high rate of full load hours. Otherwise biogas plants are also forced to limit their electricity production and have to flare the surplus gas in the case of insufficient gas storage capacity, in order to ensure power system stability and reliability during high feed-in periods from wind and solar energy. However, these modes of operation are not in compliance with the requirements of an electricity grid based on renewable power generation. Technology development is still needed for many plants to reach the necessary flexibility. Two exemplary projects funded by the German Federal Ministry for the Environment in the program for “Promoting Projects to Optimize the Use of Biomass for Energy Production” are developing systems for the controllable generation of electricity by biogas plants to meet consumer demands. The projects are described below., Proceedings of the 22nd European Biomass Conference and Exhibition, 23-26 June 2014, Hamburg, Germany, pp. 530-538
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- 2014
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10. Technical Modifications and Concepts for a Controllable Electricity Production via Biogas Plants in Germany
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Häring, G., Sonnleitner, M., Zörner, W., Hanby, V., and Bichlmeier, S.
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Biomass - Abstract
With the expansion of renewable but fluctuating power generation from wind and solar energy, the demand placed on the security and reliability of electricity supply is increasing. To ensure grid stability in the future, controllable power production via biogas plants has a great technical and economic potential. In this context, the CENTRE OF EXCELLENCE FOR RENEWABLE ENERGY RESEARCH at Ingolstadt University of Applied Sciences and the biogas plant manufacturer UTS Biogastechnik GmbH, Hallbergmoos, Germany, are working on the research project “BioStrom – Controllable Electricity Production via Biogas Plants”, funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. This paper describes first results regarding technical modifications for acontrollable electricity production via biogas plants. Furthermore, the operational mode of CHPUnits in accordance with the demand of the electricity grid and achievable additional revenues are shown by taking the limited gas storage volume into account., Proceedings of the 21st European Biomass Conference and Exhibition, 3-7 June 2013, Copenhagen, Denmark, pp. 635-641
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- 2013
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11. Efficiency Enhancement of Biogas Plants - Results from the National Funding Program 'Biomass Energy Use'
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Pfeiffer, D., Krebs, C., Liebetrau, J., Zosel, J., Schelter, M., Häring, G., Sonnleitner, M., and Zörner, W.
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Biomass - Abstract
Three exemplary projects within the program for "Promoting Projects to Optimize the Use of Biomass for Energy Production" ("Biomass energy use") funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) are presented. All projects aim to support the increase of renewable energies fraction of electricity supply and contribute to the environmentally friendly energy production and recycling of waste materials. One project gives a detailed analysis of greenhouse gas emissions by production of biogas from organic waste material at biogas plants. In the second project a mobile testing plant is developed to optimize decentralized small and medium sized biogas plants, which convert also agro-industrial biogenic waste and/or biomass from landscape conservation. The third project presents approaches to implement a system for the controllable generation of electricity by biogas plants to meet consumer demands. The provided results of the projects can be used to support the reduction of greenhouse gases in biogas production and contribute to a climate-efficient technology in general., Proceedings of the 20th European Biomass Conference and Exhibition, 18-22 June 2012, Milan, Italy, pp. 1450-1456
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- 2012
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12. Toughness and ductility improvement in complex microstructure HSS by means of microstructural parameters optimization (MISTRETO)
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DI SCHINO, Andrea, López, I. G. u. t. i. e. r. r. e. z. B., Alonso, E., Jorge, D., Medina, S., Rancel, L., Cobo, S., Eliasson, J., Zajac, S., Pettersson, H., Östberg, G., Klein, M., and Sonnleitner, M.
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- 2009
13. Scattering approach to two-colour light forces and self-ordering of polarizable particles
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Ostermann, S, primary, Sonnleitner, M, additional, and Ritsch, H, additional
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- 2014
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14. Attractive Optical Forces from Blackbody Radiation
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Sonnleitner, M., primary, Ritsch-Marte, M., additional, and Ritsch, H., additional
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- 2013
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15. Light scattering, optomechanical trapping, strain and deformation of elastic dielectric objects
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Sonnleitner, M., primary, Ritsch-Marte, M., additional, and Ritsch, H., additional
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- 2013
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16. Self-consistent optomechanical trapping, strain and deformation of elastic dielectrics
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Sonnleitner, M., primary, Ritsch-Marte, M., additional, and Ritsch, H., additional
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- 2012
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17. Optomechanical deformation and strain in elastic dielectrics
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Sonnleitner, M, primary, Ritsch-Marte, M, additional, and Ritsch, H, additional
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- 2012
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18. Optical forces, trapping and strain on extended dielectric objects
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Sonnleitner, M., primary, Ritsch-Marte, M., additional, and Ritsch, H., additional
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- 2011
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19. Ultra-Sensitive Immunodetection of 5'Methyl Cytosine for DNA Methylation Analysis on Oligonucleotide Microarrays
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Proll, J., primary, Fodermayr, M., additional, Wechselberger, C., additional, Pammer, P., additional, Sonnleitner, M., additional, Zach, O., additional, and Lutz, D., additional
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- 2006
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20. High precision densitometry of small specimen
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Sonnleitner, M., primary and Danzer, R., additional
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- 2004
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21. Hydraulic and transport properties of the plant–soil system estimated by inverse modelling
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Sonnleitner, M. A., primary, Abbaspour, K. C., additional, and Schulin, R., additional
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- 2003
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22. Single-Molecule Anisotropy Imaging
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Harms, G.S., primary, Sonnleitner, M., additional, Schütz, G.J., additional, Gruber, H.J., additional, and Schmidt, Th., additional
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- 1999
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23. A sequence in the carboxy-terminus of the a1C subunit important for targeting, conductance and open probability of L-type Ca2+ channels
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Kepplinger, K. J., Kahr, H., Forstner, G., Sonnleitner, M., Schindler, H., Schmidt, T., Groschner, K., Soldatov, N. M., and Romanin, C.
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- 2000
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24. Single-molecule anisotropy imaging
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Harms, Gs, Sonnleitner, M., and Schutz, Gj
25. Roll-to-roll manufacturing of microfluidic chips for bioanalytical applications
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Hesse, J., Anja Haase, Nees, D., Ruttloff, S., Götz, J., Özgün, P. T., Rumpler, M., Smolka, M., Kokkinis, G., Kriechhammer, G., Scheidl, D., Wilfing, B., Katzmayr, I., Sonnleitner, M., Lohse, M., and Thesen, M.
26. Designing an optimally ethanol producing E. coli strain using constrained minimal cut sets
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Jungreuthmayer, C., Sonnleitner, M., gerald striedner, Mairhofer, J., and Zanghellini, J.
27. Ecological segregation drives fine-scale cytotype distribution of Senecio carniolicus in the eastern Alps,Ekologická diferenciace jako faktor určující rozšíření cytotypů Senecio carniolicus na malém prostorovém měřítku ve východních alpách
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Hülber, K., Sonnleitner, M., Flatscher, R., Andreas Berger, Dobrovsky, R., Niessner, S., Nigl, T., Schneeweiss, M. G., Kubešová, M., Rauchová, J., Suda, J., and Schönswetter, P.
28. Ecological segregation drives fine-scale cytotype distribution of Senecio carniolicus in the Eastern Alps
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Hülber K, Sonnleitner M, Flatscher R, Berger A, Dobrovsky R, Niessner S, Nigl T, Gm, Schneeweiss, Kubešová M, Rauchová J, Suda J, and Peter Schönswetter
29. Investigation and optimization of the mixing in a biogas digester with a laboratory experiment and an artificial model substrate
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Wiedemann, L., FOSCA CONTI, Sonnleitner, M., Saidi, A., and Goldbrunner, M.
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Biomass - Abstract
The flow and mixing dynamic of biogas digester substrates are challenging to be described. Rheology has to be considered as a non-Newtonian fluid, whose viscosity changes with the strain rate. The Ostwald-de Waele power law is a well applicable mathematical relationship, which useful describes the complexity of the flow behavior, permits mathematical predictions and experimental correlations. A home-made laboratory scale-down digester has been developed at the German Technische Hochschule Ingolstadt (THI) to investigate in scientific laboratory the fluid dynamics. The real substrate has been replaced with an artificial substrate to facilitate the investigation. The fluid velocity has been observed using Particle Image Velocimetry (PIV) and Acoustic Doppler Velocimetry (ADV). Three different configurations for the mixers have been developed and investigated, using propellers with different dimensions and a paddle-mixer system. The fluid dynamics have been computational modelled with numerical methods based on the Ostwald-de Waele power law. Specific algorithms have been developed using the commercial software tool StarCCM+. The simulation outputs have been evaluated and interpreted in relation with the experimental data to validate the mixing concepts. The success of our work confirms the good correlation of numerical simulations and laboratory experimental models. It contributes to a better understanding of the mixing process in real biogas digesters, what supports the competitiveness of biogas plants in future, Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 889-892
30. Atoms crystallised by light for precision measurement.
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Holzmann, D., Sonnleitner, M., and Ritsch, H.
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QUANTUM scattering , *PHOTONS - Abstract
An abstract of the article "Self-ordering and collective dynamics of transversely illuminated point-scatterers in a 1D trap" by D. Holzmann and colleagues is presented.
- Published
- 2015
31. Thliphthisasapphus (Rubiaceae, Rubieae), a new species from Lefkada (Ionian Islands, Greece) and its ecological position.
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Gutermann W, Jang TS, Kästner A, Prehsler D, Reich D, Berger A, Flatscher R, Gilli C, Hofbauer M, Lachmayer M, Sander R, Sonnleitner M, and Mucina L
- Abstract
The new species, Thliphthisasapphus sp. nov. (Rubiaceae, Rubieae), a narrow endemic of the white cliffs of Lefkátas on the southwest coast of Lefkada (Greece) is described and illustrated and an IUCN assessment is presented. Vegetation relevés were performed at the single known locality, limestone cliffs facing the sea and revealed a new association, the Thliphthisasapphus - Lomelosietumdallaportae . The chromosome number of Thliphthisasapphus was determined as 2 n = 4 x = 44, being the single tetraploid species in the genus to date. The species also differs markedly morphologically from its morphologically closest relatives, two Greek steno-endemic oreophytes, Th.baenitzii and Th.muscosa by the following characters: densely setose mericarps and corolla, tetraploidy and by its distribution. An identification key for the Greek species of Thliphthisa is provided. Th.sapphus constitutes the westernmost outpost of a group of Greek steno-endemics, highlighting the importance of coastal habitats and their protection as refugia for poorly competitive chamaephytes., Competing Interests: The authors have declared that no competing interests exist., (Walter Gutermann, Tae-Soo Jang, Arndt Kästner, David Prehsler, Dieter Reich, Andreas Berger, Ruth Flatscher, Christian Gilli, Markus Hofbauer, Margarita Lachmayer, Ruth Sander, Michaela Sonnleitner, Ladislav Mucina.)
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- 2024
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32. An Escape Room to Teach First- and Second-Year Medical Students Nephrology.
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Hu J, Sonnleitner M, Weldon E, Kejriwal S, Brown B, and Shah A
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An escape room is a team-based activity that requires players to solve a series of puzzles to complete a story and "break out" of a room. It has recently gained traction in medical education for its ability to interactively and effectively present learning objectives. This was a prospective educational study that describes the successful application of a nephrology themed escape room for first- and second-year medical students. Compared to pre-escape room participation, the 52 students demonstrated a statistically significant improvement in self-reported knowledge for renal physiology ( p < 0.01), pharmacology ( p < 0.01), pathology ( p < 0.01), and relevant clinical practice guidelines ( p < 0.01). A majority of the students also claimed that the escape room was "more effective" than traditional lectures (80.8%) and textbooks (73.1%) and "equally effective" as third-party board preparation resources (69.2%) and their institution's problem-based learning curriculum (51.9%). The escape room also facilitated a high-level peer-to-peer collaboration with 82.7% and 76.9% of students reporting that they worked with someone in their year and outside of their year for at least half of the game, respectively. Ninety-five percent of the first-years and 84.6% of the second-years believed that the escape room was effective at preparing them for their respective exams, and an overwhelming majority (90.4%) described the escape room as "very enjoyable." Overall, this nephrology themed escape room was an engaging and well received educational modality and may be an effective supplemental study resource for medical students. Further studies are needed to assess knowledge acquisition., Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-023-01917-6., Competing Interests: Conflict of InterestThe authors declare no competing interests., (© The Author(s) under exclusive licence to International Association of Medical Science Educators 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
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- 2023
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33. Low-entry-barrier point-of-care testing of anti-SARS-CoV-2 IgG in the population of Upper Austria from December 2020 until April 2021-a feasible surveillance strategy for post-pandemic monitoring?
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Doppler C, Feischl M, Ganhör C, Puh S, Müller M, Kotnik M, Mimler T, Sonnleitner M, Bernhard D, and Wechselberger C
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- Antibodies, Viral, Austria epidemiology, Humans, Immunoglobulin G, Point-of-Care Testing, SARS-CoV-2, Seroepidemiologic Studies, COVID-19 diagnosis, COVID-19 epidemiology, Pandemics
- Abstract
Already at the very beginning of the COVID-19 pandemic, an extensive PCR and antigen testing strategy was considered necessary and subsequently also proved successful in order to limit the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections on international and national levels. However, equally important will be the continuous monitoring of the seroprevalence status of populations from defined regions to detect-in a timely manner-any recurrence of infections or an eventual decline in antibody levels of vaccinated individuals, especially in the emerging post-pandemic situation. The aim of this study was to estimate the prevalence of SARS-CoV-2-specific immunoglobulin G antibodies in the federal state of Upper Austria (Austria) during the period of December 2020 until April 2021. To achieve this goal, we have analyzed anonymized data on the immune status of self-referral volunteers that have been determined at local pharmacies through a low-entry-barrier point-of-care analysis approach. The seroprevalence values for immunoglobulin type G antibodies against SARS-CoV-2 antigens obtained by rapid diagnostic testing on peripheral blood from volunteers reflect the current population-based estimates reported in the literature as well as the positivity rates detected by PCR-screening analyses. In conclusion, broad-based monitoring of IgG antibodies by means of a point-of-care testing network represents a valuable tool to assess the current immune situation within regionally defined populations., (© 2022. The Author(s).)
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- 2022
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34. Point-of-care testing for emergency assessment of coagulation in patients treated with direct oral anticoagulants including edoxaban.
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Härtig F, Birschmann I, Peter A, Hörber S, Ebner M, Sonnleitner M, Spencer C, Bombach P, Stefanou MI, Tünnerhoff J, Mengel A, Kuhn J, Ziemann U, and Poli S
- Abstract
Background: Direct oral anticoagulants (DOAC) including edoxaban are increasingly used for stroke prevention in atrial fibrillation. Despite treatment, annual stroke rate in these patients remains 1-2%. Rapid assessment of coagulation would be useful to guide thrombolysis or reversal therapy in this growing population of DOAC/edoxaban-treated stroke patients. Employing the Hemochron™ Signature Elite point-of-care test system (HC-POCT), clinically relevant plasma concentrations of dabigatran and rivaroxaban can be excluded in a blood sample. However, no data exists on the effect of edoxaban on HC-POCT results. We evaluated whether edoxaban plasma concentrations above the current treatment thresholds for thrombolysis or anticoagulation reversal (i.e., 30 and 50 ng/mL) can be ruled out with the HC-POCT., Methods: We prospectively studied patients receiving a first dose of edoxaban. Six blood samples were collected from each patient: before, 0.5, 1, 2, 8, and 24 h after drug intake. HC-POCT-based INR (HC-INR), activated clotting time (HC-ACT+ and HC-ACT-LR), activated partial thromboplastin time (HC-aPTT), and mass spectrometry for edoxaban plasma concentrations were performed at each time-point. We calculated correlations, receiver operating characteristics (ROC) and test-specific cut-offs for ruling out edoxaban concentrations > 30 and > 50 ng/mL in a blood sample., Results: One hundred twenty blood samples from 20 edoxaban-treated patients were analyzed. Edoxaban plasma concentrations ranged from 0 to 512 ng/mL. HC-INR/HC-ACT+/HC-ACT-LR/HC-aPTT ranged from 0.7-8.3/78-310 s/65-215 s/19-93 s, and Pearson's correlation coefficients showed moderate to very strong correlations with edoxaban concentrations (r = 0.95/0.79/0.70/0.60). With areas under the ROC curve of 0.997 (95% confidence interval: 0.991-0.971) and 0.989 (0.975-1.000), HC-INR most reliably ruled out edoxaban concentrations > 30 and > 50 ng/mL, respectively, and HC-INR results ≤1.5 and ≤ 2.1 provided specificity/sensitivity of 98.6% (91.2-99.9)/98.0% (88.0-99.9) and 96.8% (88.0-99.4)/96.5% (86.8-99.4)., Conclusions: Our study represents the first systematic evaluation of the HC-POCT in edoxaban-treated patients. Applying sufficiently low assay-specific cut-offs, the HC-POCT may not only be used to reliably rule out dabigatran and rivaroxaban, but also very low edoxaban concentrations in a blood sample. Because the assay-specific cut-offs were retrospectively defined, further investigation is warranted., Trial Registration: ClinicalTrials.gov, registration number: NCT02825394 , registered on: 07/07/2016, URL.
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- 2021
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35. Lab-on-a-foil devices with integrated retro-reflective structures for multiplexed DNA testing.
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Toren P, Proksch A, Smolka M, Haase A, Nees D, Ruttloff S, Goetz J, Wolf C, Hierschlager B, Katzmayr I, Sonnleitner M, Stadlober B, and Hesse J
- Abstract
Abstract: With the Covid-19-based global pandemic that started in the beginning of 2020, the vital importance of accelerated, reliable and affordable virus testing systems has once again become clearer. Besides, we all learned very well that the disposable biochips, to be used in these in vitro diagnostic (IVD) testing systems, supposed to be produced in large amounts in a very short time to be widely available for the use of humanity to save more and more lives. That is why; roll-to-roll (R2R) polymer structuring manners offer such large quantities for the production of in vitro biochips. Our technology, based on R2R UV nanoimprint lithography (UV-NIL), has superior features. Via our pilot line, robust 7500 biochip components per 100 meter of a flexible, polymer foil coated with a UV curable photo-resin (i.e., parts with capillary fluidic channels or optical structures for IVDs) can be generated. This study shows an example of a prototype of a R2R UV-NIL generated chip: a foil, capillary flow-based IVD biochip for multiplexed DNA detection purposes (i.e., a Lab-on-a-Foil device). The biochip performance was further increased dramatically by integrating UV-NIL produced retro-reflective microstructures, which reflects the light back, to its design to enhance optical signal detection in a commercial IVD device, detecting DNA on a chemiluminescent-reaction basis., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s), under exclusive licence to The Materials Research Society 2021.)
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- 2021
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36. High-throughput roll-to-roll production of polymer biochips for multiplexed DNA detection in point-of-care diagnostics.
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Toren P, Smolka M, Haase A, Palfinger U, Nees D, Ruttloff S, Kuna L, Schaude C, Jauk S, Rumpler M, Hierschlager B, Katzmayr I, Sonnleitner M, Thesen MW, Lohse M, Horn M, Weigel W, Strbac M, Bijelic G, Hemanth S, Okulova N, Kafka J, Kostler S, Stadlober B, and Hesse J
- Subjects
- DNA genetics, Nucleic Acid Hybridization, Point-of-Care Testing, Polymers, Methicillin-Resistant Staphylococcus aureus genetics
- Abstract
Roll-to-roll UV nanoimprint lithography has superior advantages for high-throughput manufacturing of micro- or nano-structures on flexible polymer foils with various geometries and configurations. Our pilot line provides large-scale structure imprinting for cost-effective polymer biochips (4500 biochips/hour), enabling rapid and multiplexed detections. A complete high-volume process chain of the technology for producing structures like μ-sized, triangular optical out-couplers or capillary channels (width: from 1 μm to 2 mm, height: from 200 nm up to 100 μm) to obtain biochips (width: 25 mm, length: 75 mm, height: 100 μm to 1.5 mm) was described. The imprinting process was performed with custom-developed resins on polymer foils with resin thicknesses ranging between 125-190 μm. The produced chips were tested in a commercial point-of-care diagnostic system for multiplexed DNA analysis of methicillin resistant Staphylococcus aureus (e.g., mecA, mecC gene detections). Specific target DNA capturing was based on hybridisation between surface bound DNA probes and biotinylated targets from the sample. The immobilised biotinylated targets subsequently bind streptavidin-horseradish peroxidase conjugates, which in turn generate light upon incubation with a chemiluminescent substrate. To enhance the light out-coupling thus to improve the system performance, optical structures were integrated into the design. The limits-of-detection of mecA (25 bp) for chips with and without structures were calculated as 0.06 and 0.07 μM, respectively. Further, foil-based chips with fluidic channels were DNA functionalised in our roll-to-roll micro-array spotter following the imprinting. This straightforward approach of sequential imprinting and multiplexed DNA functionalisation on a single foil was also realised for the first time. The corresponding foil-based chips were able to detect mecA gene DNA sequences down to a 0.25 μM concentration.
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- 2020
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37. Point-of-care testing of coagulation in patients treated with edoxaban.
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Härtig F, Birschmann I, Peter A, Hörber S, Ebner M, Sonnleitner M, Spencer C, Bombach P, Stefanou MI, Kuhn J, Mengel A, Ziemann U, and Poli S
- Subjects
- Aged, Atrial Fibrillation drug therapy, Blood Coagulation Tests, Drug Monitoring, Factor Xa Inhibitors blood, Factor Xa Inhibitors pharmacology, Female, Humans, International Normalized Ratio, Male, Middle Aged, Point-of-Care Testing, Prospective Studies, Pyridines blood, Pyridines pharmacology, Stroke drug therapy, Thiazoles blood, Thiazoles pharmacology, Blood Coagulation drug effects, Factor Xa Inhibitors therapeutic use, Pyridines therapeutic use, Thiazoles therapeutic use
- Abstract
Edoxaban, alongside other direct oral anticoagulants (DOAC), is increasingly used for prevention of thromboembolism, including stroke. Despite DOAC therapy, however, annual stroke rate in patients with atrial fibrillation remains 1-2%. Rapid exclusion of relevant anticoagulation is necessary to guide thrombolysis or reversal therapy but, so far, no data exists on the effect of edoxaban on available point-of-care test systems (POCT). To complete our previous investigation on global coagulation-POCT for the detection of DOAC, we evaluated whether CoaguChek®-INR (CC-INR) is capable of safely ruling out edoxaban concentrations above the current treatment thresholds of 30/50 ng/mL in a blood sample. We studied patients receiving a first dose of edoxaban; excluding subjects receiving other anticoagulants. Six blood samples were collected from each patient: before drug intake, 0.5, 1, 2 and 8 h after intake, and at trough (24 h). CC-INR and mass spectrometry for edoxaban concentrations were performed for each time-point. One hundred and twenty blood samples from 20 patients contained 0-302 ng/mL of edoxaban. CC-INR ranged from 0.9 to 2.3. Pearson's correlation coefficient showed strong correlation between CC-INR and edoxaban concentrations (r = 0.73, p < 0.001). Edoxaban concentrations > 30 and > 50 ng/mL were ruled out by CC-INR ≤ 1.0 and ≤ 1.1, respectively, with high specificity (> 95%), and a sensitivity of 44% (95%-confidence interval: 30-59%) and 86% (74-93%), respectively. Our study represents the first evaluation of coagulation-POCT in edoxaban-treated patients. CC-POCT is suitable to safely exclude clinically relevant edoxaban concentrations prior to thrombolysis, or guide reversal therapy in stroke patients.
- Published
- 2020
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38. A novel method to infer the origin of polyploids from Amplified Fragment Length Polymorphism data reveals that the alpine polyploid complex of Senecio carniolicus (Asteraceae) evolved mainly via autopolyploidy.
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Winkler M, Escobar García P, Gattringer A, Sonnleitner M, Hülber K, Schönswetter P, and Schneeweiss GM
- Subjects
- DNA, Plant genetics, Europe, Evolution, Molecular, Amplified Fragment Length Polymorphism Analysis methods, Asteraceae genetics, Computational Biology methods, Polyploidy
- Abstract
Despite its evolutionary and ecological relevance, the mode of polyploid origin has been notoriously difficult to be reconstructed from molecular data. Here, we present a method to identify the putative parents of polyploids and thus to infer the mode of their origin (auto- vs. allopolyploidy) from Amplified Fragment Length Polymorphism (AFLP) data. To this end, we use Cohen's d of distances between in silico polyploids, generated within a priori defined scenarios of origin from a priori delimited putative parental entities (e.g. taxa, genetic lineages), and natural polyploids. Simulations show that the discriminatory power of the proposed method increases mainly with increasing divergence between the lower-ploid putative ancestors and less so with increasing delay of polyploidization relative to the time of divergence. We apply the new method to the Senecio carniolicus aggregate, distributed in the European Alps and comprising two diploid, one tetraploid and one hexaploid species. In the eastern part of its distribution, the S. carniolicus aggregate was inferred to comprise an autopolyploid series, whereas for western populations of the tetraploid species, an allopolyploid origin involving the two diploid species was the most likely scenario. Although this suggests that the tetraploid species has two independent origins, other evidence (ribotype distribution, morphology) is consistent with the hypothesis of an autopolyploid origin with subsequent introgression by the second diploid species. Altogether, identifying the best among alternative scenarios using Cohen's d can be straightforward, but particular scenarios, such as allopolyploid origin vs. autopolyploid origin with subsequent introgression, remain difficult to be distinguished., (© 2016 John Wiley & Sons Ltd.)
- Published
- 2017
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39. Image reconstruction from photon sparse data.
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Mertens L, Sonnleitner M, Leach J, Agnew M, and Padgett MJ
- Abstract
We report an algorithm for reconstructing images when the average number of photons recorded per pixel is of order unity, i.e. photon-sparse data. The image optimisation algorithm minimises a cost function incorporating both a Poissonian log-likelihood term based on the deviation of the reconstructed image from the measured data and a regularization-term based upon the sum of the moduli of the second spatial derivatives of the reconstructed image pixel intensities. The balance between these two terms is set by a bootstrapping technique where the target value of the log-likelihood term is deduced from a smoothed version of the original data. When compared to the original data, the processed images exhibit lower residuals with respect to the true object. We use photon-sparse data from two different experimental systems, one system based on a single-photon, avalanche photo-diode array and the other system on a time-gated, intensified camera. However, this same processing technique could most likely be applied to any low photon-number image irrespective of how the data is collected., Competing Interests: The authors declare no competing financial interests.
- Published
- 2017
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40. Will a Decaying Atom Feel a Friction Force?
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Sonnleitner M, Trautmann N, and Barnett SM
- Abstract
We show how a simple calculation leads to the surprising result that an excited two-level atom moving through a vacuum sees a tiny friction force of first order in v/c. At first sight this seems to be in obvious contradiction to other calculations showing that the interaction with the vacuum does not change the velocity of an atom. It is even more surprising that this change in the atom's momentum turns out to be a necessary result of energy and momentum conservation in special relativity.
- Published
- 2017
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41. Evaluation of novel inducible promoter/repressor systems for recombinant protein expression in Lactobacillus plantarum.
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Heiss S, Hörmann A, Tauer C, Sonnleitner M, Egger E, Grabherr R, and Heinl S
- Subjects
- Base Sequence, Blotting, Western, DNA-Directed RNA Polymerases metabolism, Isopropyl Thiogalactoside pharmacology, Lactobacillus plantarum drug effects, Lactobacillus plantarum growth & development, Lactose pharmacology, Molecular Sequence Data, Plasmids metabolism, Viral Proteins metabolism, Xylose pharmacology, Lactobacillus plantarum genetics, Promoter Regions, Genetic, Recombinant Proteins metabolism, Repressor Proteins metabolism
- Abstract
Background: Engineering lactic acid bacteria (LAB) is of growing importance for food and feed industry as well as for in vivo vaccination or the production of recombinant proteins in food grade organisms. Often, expression of a transgene is only desired at a certain time point or period, e.g. to minimize the metabolic burden for the host cell or to control the expression time span. For this purpose, inducible expression systems are preferred, though cost and availability of the inducing agent must be feasible. We selected the plasmid free strain Lactobacillus plantarum 3NSH for testing and characterization of novel inducible promoters/repressor systems. Their feasibility in recombinant protein production was evaluated. Expression of the reporter protein mCherry was monitored with the BioLector(®) micro-fermentation system., Results: Reporter gene mCherry expression was compared under the control of different promoter/repressor systems: PlacA (an endogenous promoter/repressor system derived from L. plantarum 3NSH), PxylA (a promoter/repressor system derived from Bacillus megaterium DSMZ 319) and PlacSynth (synthetic promoter and codon-optimized repressor gene based on the Escherichia coli lac operon). We observed that PlacA was inducible solely by lactose, but not by non-metabolizable allolactose analoga. PxylA was inducible by xylose, yet showed basal expression under non-induced conditions. Growth on galactose (as compared to exponential growth phase on glucose) reduced basal mCherry expression at non-induced conditions. PlacSynth was inducible with TMG (methyl β-D-thiogalactopyranoside) and IPTG (isopropyl β-D-1-thiogalactopyranoside), but also showed basal expression without inducer. The promoter PlacSynth was used for establishment of a dual plasmid expression system, based on T7 RNA polymerase driven expression in L. plantarum. Comparative Western blot supported BioLector(®) micro-fermentation measurements. Conclusively, overall expression levels were moderate (compared to a constitutive promoter)., Conclusions: We evaluated different inducible promoters, as well as an orthologous expression system, for controlled gene expression in L. plantarum. Furthermore, here we provide proof of concept for a T7 RNA polymerase based expression system for L. plantarum. Thereby we expanded the molecular toolbox for an industrial relevant and generally regarded as safe (GRAS) strain.
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- 2016
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42. Ecological differentiation of diploid and polyploid cytotypes of Senecio carniolicus sensu lato (Asteraceae) is stronger in areas of sympatry.
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Sonnleitner M, Hülber K, Flatscher R, Escobar García P, Winkler M, Suda J, Schönswetter P, and Schneeweiss GM
- Subjects
- Diploidy, Ecosystem, Ecotype, Europe, Models, Genetic, Monte Carlo Method, Senecio genetics, Polyploidy, Senecio physiology, Sympatry
- Abstract
Background and Aims: Ecological differentiation is recognized as an important factor for polyploid speciation, but little is known regarding whether the ecological niches of cytotypes differ between areas of sympatry and areas where single cytotypes occur (i.e. niche displacement)., Methods: Ecological niches of four groups of Senecio carniolicus sensu lato (s.l.) (western and eastern diploid lineages, tetraploids and hexaploids) were characterized via Landolt indicator values of the accompanying vascular plant species and tested using multivariate and univariate statistics., Key Results: The four groups of S. carniolicus s.l. were ecologically differentiated mainly with respect to temperature, light and soil (humus content, nutrients, moisture variability). Niche breadths did not differ significantly. In areas of sympatry hexaploids shifted towards sites with higher temperature, less light and higher soil humus content as compared with homoploid sites, whereas diploids and tetraploids shifted in the opposite direction. In heteroploid sites of tetraploids and the western diploid lineage the latter shifted towards sites with lower humus content but higher aeration., Conclusions: Niche displacement can facilitate the formation of stable contact zones upon secondary contact of polyploids and their lower-ploid ancestors and/or lead to convergence of the cytotypes' niches after they have attained non-overlapping ranges. Niche displacement is essential for understanding ecological consequences of polyploidy., (© The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Published
- 2016
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43. Underestimated diversity in one of the world's best studied mountain ranges: The polyploid complex of Senecio carniolicus (Asteraceae) contains four species in the European Alps.
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Flatscher R, García PE, Hülber K, Sonnleitner M, Winkler M, Saukel J, Schneeweiss GM, and Schönswetter P
- Abstract
Senecio carniolicus (Asteraceae) is an intricate polyploid complex distributed in the European Alps (di-, tetra- and hexaploids) and Carpathians (hexaploids only). Molecular genetic, ecological, and crossing data allowed four evolutionary groups within S. carniolicus to be identified. Here, we establish that these four groups (two vicariant diploid lineages, tetraploids and hexaploids) are also morphologically differentiated. As a consequence, we draw taxonomic conclusions by characterizing four species, including the more narrowly circumscribed S. carniolicus (lectotypified here), the taxonomically elevated S. insubricus comb. nov. (lectotypified here), and the two newly described species S. disjunctus and S. noricus .
- Published
- 2015
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44. Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae).
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Hülber K, Sonnleitner M, Suda J, Krejčíková J, Schönswetter P, Schneeweiss GM, and Winkler M
- Abstract
Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.
- Published
- 2015
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45. Parental ploidy strongly affects offspring fitness in heteroploid crosses among three cytotypes of autopolyploid Jacobaea carniolica (Asteraceae).
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Sonnleitner M, Weis B, Flatscher R, García PE, Suda J, Krejčíková J, Schneeweiss GM, Winkler M, Schönswetter P, and Hülber K
- Subjects
- Asteraceae physiology, Endosperm genetics, Pollination genetics, Seedlings genetics, Asteraceae genetics, Genetic Fitness, Hybridization, Genetic, Polyploidy
- Abstract
Reproductive interactions among cytotypes in their contact zones determine whether these cytotypes can co-exist and form stable contact zones or not. In autopolyploids, heteroploid cross-compatibilities might depend on parental ploidy, but tests of this hypothesis in autopolyploid systems with more than two ploidies are lacking. Here, we study Jacobaea carniolica, which comprises diploid, tetraploid, and hexaploid individuals regularly forming contact zones. Seeds obtained from in situ cross-pollinations within and among cytotypes were subjected to DNA flow cytometry and greenhouse germination experiments. Hybrid fitness and parental effects on hybrid fitness were tested with regression models comparing fitness parameters of early life stages. Irrespective of the direction of crosses, seed viability and seedling survival in diploid-polyploid crosses were substantially lower than in tetraploid-hexaploid crosses. In contrast, seedling growth traits indicated neither transgressive character expression nor any selection against hybrid offspring. Congruent with a model of genome dosage effects, these traits differed between reciprocal crosses, especially of diploids and tetraploids, where trait values resembled those of the maternal parent. The strong effect of parental ploidy on offspring fitness in heteroploid crosses may cause contact zones involving exclusively polyploid cytotypes to be less stable over longer terms than those involving diploids and polyploids.
- Published
- 2013
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46. Tackling the minority: sulfate-reducing bacteria in an archaea-dominated subsurface biofilm.
- Author
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Probst AJ, Holman HY, DeSantis TZ, Andersen GL, Birarda G, Bechtel HA, Piceno YM, Sonnleitner M, Venkateswaran K, and Moissl-Eichinger C
- Subjects
- Archaea classification, Archaea genetics, Archaea metabolism, Bacteria classification, Bacteria genetics, Bacteria metabolism, DNA, Bacterial genetics, Hydrogensulfite Reductase genetics, In Situ Hybridization, Fluorescence, Natural Springs chemistry, Phylogeny, RNA, Ribosomal, 16S genetics, Spectroscopy, Fourier Transform Infrared, Archaea physiology, Bacterial Physiological Phenomena, Biodiversity, Biofilms, Natural Springs microbiology
- Abstract
Archaea are usually minor components of a microbial community and dominated by a large and diverse bacterial population. In contrast, the SM1 Euryarchaeon dominates a sulfidic aquifer by forming subsurface biofilms that contain a very minor bacterial fraction (5%). These unique biofilms are delivered in high biomass to the spring outflow that provides an outstanding window to the subsurface. Despite previous attempts to understand its natural role, the metabolic capacities of the SM1 Euryarchaeon remain mysterious to date. In this study, we focused on the minor bacterial fraction in order to obtain insights into the ecological function of the biofilm. We link phylogenetic diversity information with the spatial distribution of chemical and metabolic compounds by combining three different state-of-the-art methods: PhyloChip G3 DNA microarray technology, fluorescence in situ hybridization (FISH) and synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy. The results of PhyloChip and FISH technologies provide evidence for selective enrichment of sulfate-reducing bacteria, which was confirmed by the detection of bacterial dissimilatory sulfite reductase subunit B (dsrB) genes via quantitative PCR and sequence-based analyses. We further established a differentiation of archaeal and bacterial cells by SR-FTIR based on typical lipid and carbohydrate signatures, which demonstrated a co-localization of organic sulfate, carbonated mineral and bacterial signatures in the biofilm. All these results strongly indicate an involvement of the SM1 euryarchaeal biofilm in the global cycles of sulfur and carbon and support the hypothesis that sulfidic springs are important habitats for Earth's energy cycles. Moreover, these investigations of a bacterial minority in an Archaea-dominated environment are a remarkable example of the great power of combining highly sensitive microarrays with label-free infrared imaging.
- Published
- 2013
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47. Extensive range persistence in peripheral and interior refugia characterizes Pleistocene range dynamics in a widespread Alpine plant species (Senecio carniolicus, Asteraceae).
- Author
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Escobar García P, Winkler M, Flatscher R, Sonnleitner M, Krejčíková J, Suda J, Hülber K, Schneeweiss GM, and Schönswetter P
- Subjects
- Amplified Fragment Length Polymorphism Analysis, Arctic Regions, Bayes Theorem, DNA, Chloroplast genetics, DNA, Plant genetics, DNA, Ribosomal Spacer genetics, Europe, Geography, Haplotypes, Ice Cover, Senecio classification, Sequence Analysis, DNA, Genetic Variation, Phylogeography, Senecio genetics
- Abstract
Recent evidence suggests that survival of arctic-alpine organisms in peripheral or interior glacial refugia are not mutually exclusive and may both be involved in shaping an organism's Pleistocene history, yet potentially at different time levels. Here, we test this hypothesis in a high-mountain plant (diploid lineage of Senecio carniolicus, Asteraceae) from the Eastern European Alps, in which patterns of morphological variation and current habitat requirements suggest survival in both types of refugia. To this end, we used AFLPs, nuclear and plastid DNA sequences and analysed them, among others, within a graph theoretic framework and using novel Bayesian methods of phylogeographic inference. On the basis of patterns of genetic diversity, occurrence of rare markers, distribution of distinct genetic lineages and patterns of range connectivity both interior refugia in the formerly strongly glaciated central Alps and peripheral refugia along the southern margin of the Alps were identified. The presence of refugia congruently inferred by markers resolving at different time levels suggests that these refugia acted as such throughout several glacial cycles. The high degree of range persistence together with gradual range expansion, which contrasts with the extent of range shifts implied for other Alpine species, is likely responsible for incipient lineage differentiation evident from the genetic data. Replacing a simplistic peripheral vs. interior refugia dualism by more complex models involving both types of refugia and considering different time levels will help identifying common phylogeographic patterns with respect to, for instance, location of refugia and colonization routes and elucidating their underlying genetic and/or ecological causes. DNA sequences have been deposited in GenBank under accession nos. FR796701–FR797793 and nos. HE614296–HE614583., (© 2012 Blackwell Publishing Ltd.)
- Published
- 2012
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48. Distribution and habitat segregation on different spatial scales among diploid, tetraploid and hexaploid cytotypes of Senecio carniolicus (Asteraceae) in the Eastern Alps.
- Author
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Sonnleitner M, Flatscher R, Escobar García P, Rauchová J, Suda J, Schneeweiss GM, Hülber K, and Schönswetter P
- Subjects
- Ecosystem, Asteraceae genetics, Asteraceae growth & development, Diploidy, Polyploidy, Tetraploidy
- Abstract
Background and Aims: The spatial distribution of cytotypes can provide valuable insights into evolutionary patterns of polyploid complexes. In a previous study the macro-scale distribution of the three main cytotypes in Senecio carniolicus (Asteraceae) within the Eastern Alps was characterized. Employing a roughly 12-fold extended sampling, the present study focuses on unravelling patterns of cytotype distribution on the meso- and microscale and on correlating those with ecological properties of the growing sites., Methods: DAPI flow cytometry of dried samples was used to determine DNA ploidy level in 5033 individuals from 100 populations spread over the entire Eastern Alpine distribution area of S. carniolicus. Descriptors of microhabitats as well as spatial data were recorded in the field, and analysed with a mixed-effects ANOVA., Key Results: Extensive variation in DNA ploidy levels (2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x) was detected. Of the main cytotypes, diploids and hexaploids were widespread and had strongly overlapping distributions resulting in the frequent occurrence of cytotype mixtures (half of the investigated populations), whereas tetraploids were disjunctly distributed and occurred in the south-west and the east of the species' distribution area. In spite of the frequent co-occurrence of cytotypes, only 1 % of the samples belonged to secondary cytotypes (3x, 5x, 7x, 8x, 9x). Diploids, tetraploids and hexaploids were altitudinally segregated, but with broad overlap. Similarly, highly significant differences in vegetation and rock cover as well as microhabitat exposure were found between the main cytotypes., Conclusions: Senecio carniolicus shows a remarkable diversity of cytotypes. The distribution of the three main cytotypes (2x, 4x, 6x) has been shaped by Pleistocene glaciations to different extents. Whereas tetraploids are nearly entirely restricted to refugia, hexaploids colonized areas that were extensively glaciated. Diploid and hexaploid individuals often co-occur in mixed populations, where they are spatially and ecologically segregated at both the meso-scale (altitudinal differentiation, exposure of the growing site) and the micro-scale (cover of vegetation and bare rock). With regard to the ecological parameters investigated, the tetraploid cytotype occupies an intermediate position. The rareness of secondary cytotypes suggests the presence of strong pre- or post-zygotic mating barriers.
- Published
- 2010
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49. Organic photodiodes for biosensor miniaturization.
- Author
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Wojciechowski JR, Shriver-Lake LC, Yamaguchi MY, Füreder E, Pieler R, Schamesberger M, Winder C, Prall HJ, Sonnleitner M, and Ligler FS
- Subjects
- Biosensing Techniques methods, Dose-Response Relationship, Drug, Electrodes, Electronics, Enterotoxins isolation & purification, Glass chemistry, Luminescence, Sensitivity and Specificity, Biosensing Techniques instrumentation, Miniaturization, Organic Chemicals chemistry
- Abstract
Biosensors have successfully demonstrated the capability to detect multiple pathogens simultaneously at very low levels. Miniaturization of biosensors is essential for use in the field or at the point of care. While microfluidic systems reduce the footprint for biochemical processing devices and electronic components are continually becoming smaller, optical components suitable for integration--such as LEDs and CMOS chips--are generally still too expensive for disposable components. This paper describes the integration of polymer diodes onto a biosensor chip to create a disposable device that includes both the detector and the sensing surface coated with immobilized capture antibody. We performed a chemiluminescence immunoassay on the OPD substrate and measured the results using a hand-held reader attached to a laptop computer. The miniaturized biosensor with the disposable slide including the organic photodiode detected Staphylococcal enterotoxin B at concentrations as low as 0.5 ng/mL.
- Published
- 2009
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50. Ecological segregation drives fine-scale cytotype distribution of Senecio carniolicus in the Eastern Alps.
- Author
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Hülber K, Sonnleitner M, Flatscher R, Berger A, Dobrovsky R, Niessner S, Nigl T, Schneeweiss GM, Kubešová M, Rauchová J, Suda J, and Schönswetter P
- Abstract
In order to uncover patterns and processes of segregation of co-existing cytotypes, we investigated a zone in the eastern Alps (Austria) where diploid and hexaploid individuals of the alpine herb Senecio carniolicus Willd. (Asteraceae) co-occur. Linking the fine-scale distribution of cytotypes to environmental and spatial factors revealed segregation along an ecological gradient, which was also reflected in the cytotype-associated plant assemblages. Compared to diploids, hexaploids are found in more species-rich and denser communities. This may be due to their better competitive ability and lower tolerance of abiotic stress compared to the diploids. The lack of any intermediate cytotypes suggests the presence of strong reproductive isolation mechanisms, whose nature is, however, elusive.
- Published
- 2009
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