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Exposure to trivalent lanthanides (Ln) and actinides (An) poses a serious health risk to animals and humans. Since both Lan and An are mainly excreted with the urine, we investigated the effect of La, Ce, Eu, and Yb (as representatives of Ln) as well as Am (as representative of An) exposure on a rat renal cell line (NRK-52E) for 8, 24, and 48 h in vitro. Cell viability studies using the XXT assay and fluorescence microscopic investigations were combined with solubility and speciation studies using ICP-MS and time-resolved laser-induced fluorescence spectroscopy (TRLFS). Thermodynamic modeling was applied to predict the speciation of Ln and Am in cell culture medium. All Ln show a concentration- and time-dependent effect on NRK-52E cells with Ce being the most potent element. Effective Ln concentrations reducing the cell viability to 50 % (EC50 values) range from 340 µM for Ce to 1.1 mM for Eu. In general, light and heavy Ln seem to exhibit a greater effect than middle Ln. In cell culture medium with 10 % fetal bovine serum (FBS), the Ln are completely soluble and complexed with proteins from FBS. Ln speciation is time-independent. Comparative experiment with Am are ongoing and will reveal analogies and differences in the effect of trivalent Ln and An on rat kidney cells. The results of this study underline the importance of combining biological, chemical, and spectroscopic methods in studying the effect of Ln and An on cells in vitro and may contribute to the improvement of the current risk assessment for Ln in the human body. Furthermore, they demonstrate that Ln seem to have no effect on rat renal cells in vitro at environmental trace concentrations. Nevertheless, especially Ce has the potential for harmful effects at elevated concentrations observed in mining and industrial areas. References: [1] A. Heller, Ecotox. Environ. Safe. 2019, 173.

Exposure to trivalent lanthanides (Ln) and actinides (An) poses a serious health risk to animals and humans. Since both Ln and An are mainly excreted with the urine, we investigated the effect of La, Ce, Eu, and Yb (as representatives of Ln) as well as Am (as representative of An) exposure on a rat kidney cell line (NRK-52E) for 8, 24, and 48 h in vitro. Cell viability studies using the XTT assay and fluorescence microscopic investigations were combined with solubility and speciation studies using ICP-MS and time-resolved laser-induced fluorescence spectroscopy (TRLFS). Thermodynamic modeling was applied to predict the speciation of Ln and Am in cell culture medium. All Ln show a concentration- and time-dependent effect on NRK-52E cells with Ce being the most potent element. Effective Ln concentrations reducing the cell viability to 50 % (EC50 values) range from 340 µM for Ce to 1.1 mM for Eu. In general, light and heavy Ln seem to exhibit a greater effect than middle Ln. In cell culture medium with 10 % fetal bovine serum (FBS), the Ln are completely soluble and complexed with proteins from FBS. Ln speciation is time-independent. Comparative experiments with Am are ongoing and will reveal analogies and/or differences in the effect of trivalent Ln and An on rat kidney cells. This is the first study revealing the effects of Ln onto mammalian kidney cells. Furthermore, our laboratory is one of the few worldwide, which is able to perform cell culture studies using radioactive elements like Am. The results of this study underline the importance of combining biological, chemical, and spectroscopic methods in studying the effect of Ln and An on cells in vitro and may contribute to the improvement of the current risk assessment for Ln in the human body. Furthermore, they demonstrate that Ln seem to have no effect on rat renal cells in vitro at environmental trace concentrations. Nevertheless, especially Ce has the potential for harmful effects at elevated concentrations observed in mining and industrial areas.

Concrete widely serves as an engineering barrier and for waste conditioning in nuclear waste re-positories. Organic additives like poly(hydroxyl)carboxylates are commonly used for tuning the physico-chemical and mechanical properties of fresh concrete. In the worst-case scenario of wa-ter intrusion into the waste repository, the concrete may degrade, so that the soluble organic ad-ditives will be leached out and may form stable radionuclide (RN) complexes. Consequently, for a long-term risk assessment in nuclear waste repositories, the interactions of RNs with cement additives and CSH phases (main phase of cement) must be known. Americium(III) is one of the RN that will determine the radiotoxicity of a waste repository for a long time. As a model com-pound for cement additives malic acid (α-hydroxydicarboxylic acid) was chosen...

Concrete widely serves as an engineering barrier and for waste conditioning in nuclear waste re-positories. Organic additives like poly(hydroxyl)carboxylates are commonly used for tuning the physico-chemical and mechanical properties of fresh concrete. In the worst-case scenario of wa-ter intrusion into the waste repository, the concrete may degrade, so that the soluble organic ad-ditives will be leached out and may form stable radionuclide (RN) complexes. Consequently, for a long-term risk assessment in nuclear waste repositories, the interactions of RNs with cement additives and CSH phases (main phase of cement) must be known. Americium(III) is one of the RN that will determine the radiotoxicity of a waste repository for a long time. As a model com-pound for cement additives malic acid (α-hydroxydicarboxylic acid) was chosen...

Threats to control have been found to increase belief in conspiracy theories. We argue, however, that previous research observing this effect was limited in two ways. First, previous research did not exclude the possibility that affirming control might reduce conspiracy beliefs. Second, because of artificial lab procedures, previous findings provide little information about the external validity of the control threat-conspiracy belief relationship. In Study 1, we address the first limitation and find that affirming control indeed reduces belief in conspiracy theories as compared with a neutral baseline condition. In Study 2, we address the second limitation of the literature. In a large-scale US sample, we find that a societal threat to control, that citizens actually experienced, predicts belief in a range of common conspiracy theories. Taken together, these findings increase insight in the fundamental relationship between the human need for control and the tendency to believe in conspiracy theories.

The similar chemical properties of f-block elements are still a challenging task in the separation of nuclear fuel waste material by hydrometallurgical methods. Extractants based on phosphorus (e.g. D2EHPA, PC88A, TBP) are typically used in industrial recovery processes.1, 2 Chelating agents, such as 4-acylpyrazolones received remarkable attention as extractants for rare earth elements.3 Our approach is to achieve suitable reagents for selective separation of lanthanides and actinides by implementing the phosphoryl group in the backbone of pyrazolones. This is the first publication on 4-phosphorylpyrazolones4, 5 with respect to their coordination behaviour towards f-block elements.

Small organic molecules like lactic acid (HO-CH(CH3)-COOH), which can bind heavy metal ions, are ubiquitous in nature. They can be found in nearly all biological systems as a product of various biochemical processes and in the geosphere as well, i.e. as part of organic matter of argillaceous rocks. This renders lactate a suitable model molecule for a multi-technique structure determination. Eu(III) was chosen as non-radioactive model for trivalent actinides. Current structural suggestions for the Eu(III) lactate are only assumptions from indirect methods [1,2]. We want to provide direct structural information. ATR FT-IR spectroscopy combined with calculations of structure and spectroscopic data using DFT reveals structural features. Lanthanide induced shifts (LIS) in NMR spectroscopy as caused by the interaction of nuclear spins with electronic unpaired spins can be used as a helpful tool for signal separation, probing the potential binding sites and structure including geometries and distances [3]. The combination of all these methods offers new insights concerning the structure of the Eu(III) lactate 1:1 complex thereby resolving contradictions in the previous works whether the hydroxyl group is protonated or not. From ATR FT-IR measurements, bidentate coordination of exclusively the carboxylate group could be ruled out because of the characteristic degree of spectral splitting of the asymmetric and symmetric stretching vibrations νas and νs of the carboxylate group. The best accordance of the DFT calculated vibrational spectra to the measured spectrum is given for monodentate coordinating carboxylate group and additional coordination of the deprotonated hydroxyl group (Fig. 1). NMR findings strongly support the results obtained from ATR FT-IR measurements in combination with DFT calculations. The correlation between the chemical shift changes of the 13C NMR signals and the Eu-C distances calculated by DFT suites perfectly this structure model [4]. The finding that the hydroxyl group seems to be deprotonated under complex formation [4] contradicts former structure suggestions, which suppose a coordination of the trivalent metal ion with the protonated hydroxyl group [1,2]. Both experimental methods, ATR FT-IR and NMR, as well as the DFT calculations yielded an impressively homogeneous structural explanation of the investigated Eu(III) lactate 1:1 species. [1] Tian, G.X. et al. (2010) Inorg. Chem. 49, 10598-10605. [2] Dickins, R.S. et al. (2002) J. Am. Chem. Soc. 124, 12697-12705. [3] Mayo, B.C. (1973) Chem. Soc. Rev. 2, 49-74. [4] Barkleit, A. et al. (2014) Dalton Trans. DOI: 10.1039/c4dt00440j

Thermodynamic parameters for the complex formation of Am(III) and Eu(III) with lactate were determined with UV-vis and time-resolved laser-induced fluorescence spectroscopy (TRLFS) in a temperature range between 25 and 70 °C. The reaction enthalpy decreased with increasing ionic strength. FT-IR and NMR spectroscopy in combination with density functional theory (DFT) calculations revealed structural details of the Eu(III) lactate complex: a chelating coordination mode of the lactate with a monodentate binding carboxylate group and the hydroxyl group being deprotonated.