Lenz, Markus

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Markus
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Lenz, Markus

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Thema: 500 - Naturwissenschaften ×

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  • Vorschaubild
    Publikation
    Rapid sequestration of perovskite solar cell-derived lead in soil
    (Elsevier, 08/2022) Schmidt, Felix; Ledermann, Luca; Schäffer, Andreas; Snaith, Henry J.; Lenz, Markus [in: Journal of Hazardous Materials]
    Efficient and stable perovskite solar cells rely on the use of Pb species potentially challenging the technologies’ commercialisation. In this study, the fate of Pb derived from two common perovskite precursors is compared to cationic lead in soil-water microcosm experiments under various biogeochemical conditions. The rapid and efficient removal of Pb from the aqueous phase is demonstrated by inductively coupled plasma mass spectrometry. Sequential soil extraction results reveal that a substantial amount of Pb is associated with immobile fractions, whereas a minor proportion of Pb may become available again in the long term, when oxygen is depleted (e.g. during water logging). X-ray absorption spectroscopy results reveal that the sorption of Pb on mineral phases represents the most likely sequestration mechanism. The obtained results suggest that the availability of leached Pb from perovskite solar cells is naturally limited in soils and that its adverse effects on soil biota are possibly negligible in oxic soils. All three Pb sources used behaved very similar in the experiments, wherefore we conclude that perovskite derived Pb will have a similar fate compared to cationic Pb, so that established risk assessment considerations for Pb remain legitimate.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Nanofiltration-enhanced solvent extraction of scandium from TiO acid waste
    (American Chemical Society, 27.04.2022) Yagmurlu, Bengi; Huang, Danyu; von Arx, Oliver; Dittrich, Carsten; Constable, Edwin; Friedrich, Bernd; Hedwig, Sebastian; Lenz, Markus [in: ACS Sustainable Chemistry & Engineering]
    Scandium is a critical raw material with a technological potential to reduce transportation costs and CO2 emissions. However, global supply and market adoption are crucially impaired by the lack of high-grade Sc ores and recovery strategies. A tandem nanofiltration solvent extraction route is demonstrated to enable effective Sc recovery from real-world acid waste from the chloride TiO2 production route. The process involving several filtration stages, solvent extraction, and precipitation was optimized, ultimately producing >97% pure (NH4)3ScF6.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Magnesium sensing via LFA-1 regulates CD8+ T cell effector function
    (Cell Press, 2022) Lötscher, Jonas; Martí i Líndez, Adrià-Arnau; Kirchhammer, Nicole; Cribioli, Elisabetta; Giordano Attianese, Greta Maria Paola; Trefny, Marcel P.; Rothschild, Sacha I.; Strati, Paolo; Künzli, Marco; Lotter, Claudia; Schenk, Susanne H.; Dehio, Philippe; Löliger, Jordan; Litzler, Ludivine; Schreiner, David; Koch, Victoria; Page, Nicolas; Lee, Dahye; Grählert, Jasmin; Kuzmin, Dmitry; Burgener, Anne-Valérie; Merkler, Doron; Pless, Miklos; Balmer, Maria L.; Reith, Walter; Huwyler, Jörg; Irving, Melita; King, Carolyn G.; Zippelius, Alfred; Hess, Christoph; Lenz, Markus [in: Cell]
    The relevance of extracellular magnesium in cellular immunity remains largely unknown. Here, we show that the co-stimulatory cell-surface molecule LFA-1 requires magnesium to adopt its active conformation on CD8+ T cells, thereby augmenting calcium flux, signal transduction, metabolic reprogramming, immune synapse formation, and, as a consequence, specific cytotoxicity. Accordingly, magnesium-sufficiency sensed via LFA-1 translated to the superior performance of pathogen- and tumor-specific T cells, enhanced effectiveness of bi-specific T cell engaging antibodies, and improved CAR T cell function. Clinically, low serum magnesium levels were associated with more rapid disease progression and shorter overall survival in CAR T cell and immune checkpoint antibody-treated patients. LFA-1 thus directly incorporates information on the composition of the microenvironment as a determinant of outside-in signaling activity. These findings conceptually link co-stimulation and nutrient sensing and point to the magnesium-LFA-1 axis as a therapeutically amenable biologic system.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Recovery of scandium from acidic waste solutions by means of polymer inclusion membranes
    (Elsevier, 2022) Hedwig, Sebastian; Kraus, Manuel; Amrein, Meret; Stiehm, Johannes; Constable, Edwin C.; Lenz, Markus [in: Hydrometallurgy]
    Scandium is a raw material with properties that promise considerable potential for application in alloys to enable aviation fuel savings and as dopants for use in sustainable energy production using solid oxide fuel cells. Despite these attractive properties, scandium is rarely used due to its scarcity and unreliable supply. Therefore, new strategies for scandium recovery are of economic priority. In this study, polymer inclusion membranes (PIMs) consisting of PVDF-HFP, 2-NPOE and DEHPA, were optimised for selective scandium separation from real TiO2 production waste. With the optimised system, >60% of the scandium was recovered with high selectivity, resulting in scandium mole fraction at more than two orders of magnitude higher in the receiving phase than in the original waste. This suggests PIMs may be an effective way to recover scandium from bulk waste, thus easing the scarcity and insecurity that currently limit its bulk application.
    01A - Beitrag in wissenschaftlicher Zeitschrift