@article{SchaeferHildenbrandHausmann2024, author = {Sch{\"a}fer, Myriam and Hildenbrand, Georg and Hausmann, Michael}, title = {Impact of Gold Nanoparticles and Ionizing Radiation on Whole Chromatin Organization as Detected by Single-Molecule Localization Microscopy}, series = {International Journal of Molecular Sciences}, volume = {25}, journal = {International Journal of Molecular Sciences}, number = {23}, publisher = {MDPI AG}, issn = {1422-0067}, doi = {https://doi.org/10.3390/ijms252312843}, year = {2024}, abstract = {In radiation tumor therapy, irradiation, on one hand, should cause cell death to the tumor. On the other hand, the surrounding non-tumor tissue should be maintained unaffected. Therefore, methods of local dose enhancements are highly interesting. Gold nanoparticles, which are preferentially uptaken by very-fast-proliferating tumor cells, may enhance damaging. However, the results in the literature obtained from cell culture and animal tissue experiments are very contradictory, i.e., only some experiments reveal increased cell killing but others do not. Thus, a better understanding of cellular mechanisms is required. Using the breast cancer cell model SkBr3, the effects of gold nanoparticles in combination with ionizing radiation on chromatin network organization were investigated by Single-Molecule Localization Microscopy (SMLM) and applications of mathematical topology calculations (e.g., Persistent Homology, Principal Component Analysis, etc.). The data reveal a dose and nanoparticle dependent re-organization of chromatin, although colony forming assays do not show a significant reduction of cell survival after the application of gold nanoparticles to the cells. In addition, the spatial organization of γH2AX clusters was elucidated, and characteristic changes were obtained depending on dose and gold nanoparticle application. The results indicate a complex response of ALU-related chromatin and heterochromatin organization correlating to ionizing radiation and gold nanoparticle incorporation. Such complex whole chromatin re-organization is usually associated with changes in genome function and supports the hypothesis that, with the application of gold nanoparticles, not only is DNA damage increasing but also the efficiency of DNA repair may be increased. The understanding of complex chromatin responses might help to improve the gold nanoparticle efficiency in radiation treatment.}, subject = {Krebs, Medizin}, language = {en} } @article{RodenerSchaeferHausmannetal.2022, author = {Rodener, Daniel and Sch{\"a}fer, Myriam and Hausmann, Michael and Hildenbrand, Georg}, title = {Assessing the Potential for Liquid Solvents from X-ray Sources: Considerations on Bodies Orbiting Active Galactic Nuclei}, series = {Galaxies}, volume = {10}, journal = {Galaxies}, number = {5}, publisher = {MDPI AG}, issn = {2075-4434}, doi = {https://doi.org/10.3390/galaxies10050101}, year = {2022}, abstract = {We aim to establish a rough first prospect on the potential of certain biorelevant solvents (water, ammonia, and methane) being present in liquid form inside the uppermost few meters of several modeled rocky and icy surfaces of hypothetical bodies orbiting active galactic nuclei (AGNs) and investigate under which constraints this might occur. For this, we adjust and average X-ray spectra from a sample of 20 Type-1 Seyfert galaxies to calculate the mean snowline of the sample used. We then vary the hypothetical body's orbit between 10\% and 100\% of the snowline radius and calculate a sub-surface attenuation within four different model surface compositions for each. We then use this as a continuous source term for a thermal model. Example bodies are systematically investigated with sizes between 1/30 and 20 earth radii, with further variations also considered (such as possible bound rotation), to end up with a perspective of solvent phases under a wide slew of different conditions. We find that liquid solvents are possible under a multitude of parameters, with temperature being the main constraint to liquid water whereas body size and pressure are the main constraint to liquid methane and ammonia.}, subject = {L{\"o}sungsmittel}, language = {en} } @incollection{HildenbrandPaschekSchaeferetal.2022, author = {Hildenbrand, Georg and Paschek, Klaus and Sch{\"a}fer, Myriam and Hausmann, Michael}, title = {Cryovolcanism in the Solar System and beyond: Considerations on Energy Sources, Geological Aspects, and Astrobiological Perspectives}, series = {Astronomy and Planetary Science - From Cryovolcanism to Black Holes and Galactic Evolution}, booktitle = {Astronomy and Planetary Science - From Cryovolcanism to Black Holes and Galactic Evolution}, publisher = {IntechOpen}, isbn = {9781803561196}, doi = {https://doi.org/10.5772/intechopen.105067}, year = {2022}, abstract = {Volcanism based on melting rocks (silicate volcanism) is long known on Earth and has also been found on Jupiter's moon Io. Remnants of this type of volcanism have been identified also on other bodies in the solar system. Energy sources powered by accretion and the decay of radioactive isotopes seem to be dominant mainly inside larger bodies, which have enough volume to accumulate and retain this energy in significant amounts. On the other hand, the impact of tidal forces allows even tiny bodies to melt up and pass into the stage of cryovolcanism. The dependence of tidal heating on the size of the object is minor, but the masses of and the distances to accompanying bodies as well as the inner compositions of the heated body are central factors. Even though Io as an example of a body supporting silicate volcanism is striking, the physics of tidal forces might suggest a relatively high probability for cryovolcanism. This chapter aims at considering the parameters known and objects found so far in our solar system to give insights into where in our system and other planetary systems cryovolcanism might be expected.}, subject = {Sonnensystem}, language = {en} }