| 1. |
- Biber, H., et al.
(författare)
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Sputtering Behavior of Rough, Polycrystalline Mercury Analogs
- 2022
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Ingår i: The Planetary Science Journal. - : Institute of Physics (IOP). - 2632-3338. ; 3:12
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Tidskriftsartikel (refereegranskat)abstract
- The solar wind continuously impacts on rocky bodies in space, eroding their surface, thereby contributing significantly to the exosphere formations. The BepiColombo mission to Mercury will investigate the Hermean exosphere, which makes an understanding of the precise formation processes crucial for evaluation of the acquired data. We therefore developed an experimental setup with two microbalances that allows us to compare the sputter behavior of deposited thin solid layers with that of real mineral samples in the form of pressed powder. In addition, this technique is used to study the angular distribution of the sputtered particles. Using 4 keV He+ and 2 keV Ar+ ions, the sputter behavior of pellets of the minerals enstatite (MgSiO3) and wollastonite (CaSiO3) is studied, because these minerals represent analogs for the surface of the planet Mercury or the Moon. Pellets of powdered enstatite show significantly lower sputter yields than thin amorphous enstatite films prepared by pulsed laser deposition. 3D simulations of sputtering based on surface topography data from atomic force microscopy show that the observed reduction can be explained by the much rougher pellet surface alone. We therefore conclude that sputter yields from amorphous thin films can be applied to surfaces of celestial bodies exposed to ion irradiation, provided the effects of surface roughness, as encountered in realistic materials in space, are adequately accounted for. This also implies that taking surface roughness into account is important for modeling of the interaction of the solar wind with the surface of Mercury.
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| 2. |
- Mezger, A, et al.
(författare)
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High-throughput chromatin accessibility profiling at single-cell resolution
- 2018
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1, s. 3647-
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Tidskriftsartikel (refereegranskat)abstract
- Here we develop a high-throughput single-cell ATAC-seq (assay for transposition of accessible chromatin) method to measure physical access to DNA in whole cells. Our approach integrates fluorescence imaging and addressable reagent deposition across a massively parallel (5184) nano-well array, yielding a nearly 20-fold improvement in throughput (up to ~1800 cells/chip, 4–5 h on-chip processing time) and library preparation cost (~81¢ per cell) compared to prior microfluidic implementations. We apply this method to measure regulatory variation in peripheral blood mononuclear cells (PBMCs) and show robust, de novo clustering of single cells by hematopoietic cell type.
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| 3. |
- Palm, Anna-Karin E., et al.
(författare)
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Function and regulation of self-reactive marginal zone B cells in autoimmune arthritis
- 2015
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Ingår i: Cellular & Molecular Immunology. - : Springer Science and Business Media LLC. - 1672-7681 .- 2042-0226. ; 12:4, s. 493-504
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Tidskriftsartikel (refereegranskat)abstract
- Polyreactive innate-type B cells account for many B cells expressing self-reactivity in the periphery. Improper regulation of these B cells may be an important factor that underlies autoimmune disease. Here we have explored the influence of self-reactive innate B cells in the development of collagen-induced arthritis (CIA), a mouse model of rheumatoid arthritis. We show that splenic marginal zone (MZ), but not B-1 B cells exhibit spontaneous IgM reactivity to autologous collagen II in naive mice. Upon immunization with heterologous collagen II in complete Freund's adjuvant the collagen-reactiveMZ B cells expanded rapidly, while the B-1 B cells showed a modest anti-collagen response. The MZ B cells were easily activated by toll-like receptor (TLR) 4 and 9-ligands in vitro, inducing proliferation and cytokine secretion, implying that dual engagement of the B-cell receptor and TLRs may promote the immune response to self-antigen. Furthermore, collagen-primed MZ B cells showed significant antigen-presenting capacity as reflected by cognate T-cell proliferation in vitro and induction of IgG anti-collagen antibodies in vivo. MZ B cells that were deficient in complement receptors 1 and 2 demonstrated increased proliferation and cytokine production, while Fc gamma receptor IIb deficiency of the cells lead to increased cytokine production and antigen presentation. In conclusion, our data highlight self-reactive MZ B cells as initiators of the autoimmune response in CIA, where complement and Fc receptors are relevant in controlling the self-reactivity in the cells.
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| 4. |
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| 5. |
- Pandey, Om Prakash, et al.
(författare)
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Geochronology, whole-rock geochemistry and Sr-Nd isotopes of the Bhanupratappur mafic dyke swarm : Evidence for a common Paleoproterozoic LIP event at 2.37–2.36 Ga in the Bastar and Dharwar cratons
- 2020
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Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268. ; 347
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Tidskriftsartikel (refereegranskat)abstract
- Mafic dykes and dyke swarms in continental settings provide information on the evolution of the subcontinental mantle and can be key elements in the reconstruction of paleo-geographic settings of now separated crustal terranes. This study focuses on the petrogenesis and geochronology of mafic dykes of the WNW (~125°) trending Bhanupratappur swarm in the central Bastar Craton, central India. Dykes of the Bhanupratappur swarm yield an average U-Pb (ID-TIMS) baddeleyite age of 2360 ± 4 Ma, which is interpreted as their emplacement age. The compositions of the dykes range from tholeiitic basalt to basaltic-andesite. Their rare earth element and multi-element patterns indicate the involvement of a crustal component in their petrogenesis. The whole rock initial 87Sr/86Sr2360 Ma ranges from 0.70097 to 0.70506 with most being more radiogenic than the contemporaneous undifferentiated mantle reservoir (i.e. 87Sr/86Sr2360 Ma = 0.70173). The initial εNd 2360 Ma (+0.85 to −2.7) are chondritic to sub-chondritic. The Sr-Nd Isotope composition and major- and trace element chemistry suggest an enriched-heterogeneous mantle source. The closely matching ages and chemistry of the Bhanupratappur swarm (2360 Ma) and the Karimnagar-Bangalore swarms (2363–2369 Ma) of the Dharwar Craton indicate affinities to a common Large Igneous Province, which further implies that the Bastar and Dharwar cratons were already juxtaposed at 2.37–2.36 Ga. The dykes of the Bhanupratappur (WNW-trending) and Bangalore (E-W trending) swarms converge towards the east indicating a plume center in the east. If the Karimnagar swarm was also linked (and was converging) to the same plume, the present-day mismatch in the orientations of the Karimnagar dykes (NE- to ENE-trending) with the Bangalore and Bhanupratappur dykes may indicate a ~55° counterclockwise rotation of the northern block of the Eastern Dharwar Craton with respect to the southern block after 2.37–2.36 Ga.
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| 6. |
- Roszjar, J., et al.
(författare)
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Prolonged magmatism on 4 Vesta inferred from Hf–W analyses of eucrite zircon
- 2016
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Ingår i: Earth and Planetary Science Letters. - : Elsevier BV. - 0012-821X .- 1385-013X. ; 452, s. 216-226
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Tidskriftsartikel (refereegranskat)abstract
- The asteroid 4 Vesta is the second most massive planetesimal in the Solar System and a rare example of a planetary object that possibly can be linked to a specific group of differentiated meteorites, the howardite–eucrite–diogenite suite. The 182Hf–182W chronometry of individual zircon grains from six basaltic eucrites revealed distinct growth episodes ranging from 4532 −11/+6 Ma−11/+6 Ma to 4565.0±0.9 Ma4565.0±0.9 Ma and constrains the early thermal history of 4 Vesta, indicating that its mantle generated basaltic melts for at least 35 million years (Myr). Initially, the energy needed for melting was provided by decay of short-lived isotopes, mostly 26Al. The long duration of magmatism despite the short lifetime of 26Al implies that the asteroid must have accreted within the first ∼4 Myr of Solar System formation, similar to the formation of iron meteorite parent bodies, and that its interior must have been thermally well insulated by an early-formed crust that prevented heat loss.
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| 7. |
- Szabo, P. S., et al.
(författare)
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Experimental Insights Into Space Weathering of Phobos : Laboratory Investigation of Sputtering by Atomic and Molecular Planetary Ions
- 2020
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Ingår i: Journal of Geophysical Research - Planets. - : AMER GEOPHYSICAL UNION. - 2169-9097 .- 2169-9100. ; 125:12
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Tidskriftsartikel (refereegranskat)abstract
- Investigating the space weathering of the Martian moon Phobos represents an important step toward understanding the development from its origin to its present-day appearance. Depending on Phobos' orbital position, its surface is continuously sputtered by the solar wind and planetary ions that originate in the Martian atmosphere. Based on Mars Atmosphere and Volatile Evolution measurements, it has been proposed that sputtering by planetary O+ and O-2(+) ions dominates in the Martian tail region, where the planet mostly shadows Phobos from the solar wind. In these models, uncertainties for sputtering yield inputs still exist due to the lack of sufficient analog experiments. Therefore, sputtering measurements with O+, O-2(+), C+, and CO2+ ions between 1 and 5 keV were performed using augite samples as Phobos analogs. The experimental results for O+ irradiations show smaller mass changes than predicted by SDTrimSP simulations, which probably can be attributed to O implantation enabled by the Fe content of the target. Sputtering with O-2(+) and CO2+ in the low keV range shows no deviations in the sputtering yields attributable to molecular effects. Therefore, CO2+ ions will most likely be negligible for the sputtering of Phobos according to the current understanding of ion fluxes on the Martian moon. Ultimately, our experiments suggest that the sputtering contribution on Phobos by O ions is about 50% smaller than previously assumed. This does not change the qualitative outcome from previous modeling stating that planetary O ions are by far the dominant sputtering contribution on Phobos in the Martian tail region.
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| 8. |
- Wabnitz, K, et al.
(författare)
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National Planetary Health learning objectives for Germany: A steppingstone for medical education to promote transformative change
- 2023
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Ingår i: Frontiers in public health. - : Frontiers Media SA. - 2296-2565. ; 10, s. 1093720-
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Tidskriftsartikel (refereegranskat)abstract
- Physicians play an important role in adapting to and mitigating the adverse health effects of the unfolding climate and ecological crises. To fully harness this potential, future physicians need to acquire knowledge, values, skills, and leadership attributes to care for patients presenting with environmental change-related conditions and to initiate and propel transformative change in healthcare and other sectors of society including, but not limited to, the decarbonization of healthcare systems, the transition to renewable energies and the transformation of transport and food systems. Despite the potential of Planetary Health Education (PHE) to support medical students in becoming agents of change, best-practice examples of mainstreaming PHE in medical curricula remain scarce both in Germany and internationally. The process of revising and updating the Medical Licensing Regulations and the National Competency-based Catalog of Learning Objectives for Medical Education in Germany provided a window of opportunity to address this implementation challenge. In this article, we describe the development and content of national Planetary Health learning objectives for Germany. We anticipate that the learning objectives will stimulate the development and implementation of innovative Planetary Health teaching, learning and exam formats in medical schools and inform similar initiatives in other health professions. The availability of Planetary Health learning objectives in other countries will provide opportunities for cross-country and interdisciplinary exchange of experiences and validation of content, thus supporting the consolidation of Planetary Health learning objectives and the improvement of PHE for all health professionals globally.
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