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Polycrystalline samples of Sr 0.95 Eu 0.05 Ba 8 [BN 2 ] 6 and Eu 0.937 Ba 8 [BN 2 ] 6 were synthesized via conventional solid-state reaction from the binary precursor compounds Sr 3 N 2 , EuN, Ba 3 N 2 and BN at 1000 °C. The structure of Eu 0.937 Ba 8 [BN 2 ] 6 was refined from single crystal X-ray diffractometer data: Eu 0.937 Ba 8 [BN 2 ] 6 type, Fd 3 ¯ m, a = 1594.54(9) pm, w R 2 = 0.0654, 380 F 2 values and 23 variables. The 8 a europium site shows an occupancy of only 93.7(9) % suggesting partial oxidation of europium to fulfil an electron-precise description, i. e. Eu II 0.81 Eu III 0.13 Ba 8 [BN 2 ] 6 . The mixed europium valence was confirmed by magnetic susceptibility measurements (reduced magnetic moment of 7.28 μ B per europium atom) and 151 Eu Mossbauer spectroscopy (Eu II : Eu III = 82: 18). The nitridoborate anions are coordinated by slightly distorted, mono-capped (europium) square prisms formed by the barium atoms. All metal cations are hexa-coordinated by nitrogen atoms. The EPR spectra of Eu x Sr 1-x Ba 8 [BN 2 ] 6 samples (0.001 ≤ x ≤ 0.01) suggest close to cubic local symmetry of the Eu 2+ dopant ions and reveal some highly unusual features: Magnetic hyperfine splitting is only observed with one of the Eu nuclear isotopes, and the coupling constant of 243.6 MHz is extremely large compared to values (90–100 MHz) typically observed in the literature for Eu 2+ doped crystalline materials.

Since the 1980s, the broad application of gadolinium(Gd)-based contrast agents for magnetic resonance imaging (MRI) has led to significantly increased concentrations of Gd in the aqueous environment. Little is known about the stability of these highly polar xenobiotics under environmental conditions, in wastewater and in drinking water treatment. Therefore, the stability of frequently applied Gd-based MRI contrast agents towards UV radiation was investigated. The hyphenation of hydrophilic interaction liquid chromatography (HILIC) with inductively coupled plasma mass spectrometry (ICP-MS) and of HILIC with electrospray ionization mass spectrometry (ESI-MS) provided quantitative elemental information as well as structural information. The contrast agents Gd-DTPA, Gd-DOTA and Gd-BT-DO3A showed a high stability in irradiation experiments applying a wavelength range from 220 nm to 500 nm. Nevertheless, the degradation of Gd-BOPTA as well as the formation of Gd-containing transformation products was observed by means of HILIC-ICP-MS. Matrix-dependent irradiation experiments showed a degradation of Gd-BOPTA down to 3% of the initial amount in purified water after 300 min, whereas the degradation was slowed down in drinking water and surface water. Furthermore, it was observed that the sum of species continuously decreased with proceeding irradiation in all matrices. After irradiation in purified water for 300 min only 16% of the sum of species was left. This indicates a release of Gd(III) ions from the complex in course of irradiation. HILIC-ESI-MS measurements revealed that the transformation products mostly resulted from O-dealkylation and N-dealkylation reactions. In good correlation with retention times, the majority of transformation products were found to be more polar than Gd-BOPTA itself. Based on accurate masses, sum formulas were obtained and structures could be proposed.

A new and powerful active anode system that can be operated in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) has been discovered. In HFIP the molybdenum anode forms a compact, conductive, and electroactive layer of higher-valent molybdenum species. This system can replace powerful but stoichiometrically required MoV reagents for the dehydrogenative coupling of aryls. This electrolytic reaction is more sustainable and allows the conversion of a broad scope of activated arenes.

Laser ablation-inductively coupled plasma-optical emission spectroscopy (LA-ICP-OES) is presented as a valuable tool for elemental bioimaging of alkali and earth alkali elements in plants. Whereas LA-ICP-OES is commonly used for micro analysis of solid samples, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) has advanced to the gold standard for bioimaging. However, especially for easily excitable and ubiquitous elements such as alkali and earth alkali elements, LA-ICP-OES holds some advantages regarding simultaneous detection, costs, contamination, and user-friendliness. This is demonstrated by determining the calcium, sodium and potassium distribution in tobacco plant stem and leaf petiole tissues. A quantification of the calcium contents in a concentration range up to 1000 μg g−1 using matrix-matched standards is presented as well. The method is directly compared to a LA-ICP-MS approach by analyzing parallel slices of the same samples.

Calcium-alginate aerogels augmented with zinc and silver can provide the next generation superabsorbent medical devices for advanced wound care with high cell and tissue tolerability and controlled compound release rates during wound healing. In this study, we addressed the fabrication and metal detection of alginate-based aerogels with these immunoactive cations. All three cations were incorporated into the alginate aerogel, albeit in different quantities, due to different magnitudes of leaching during solvent exchange step; an effect not reported previously. Silver addition led to an increase in aerogel zinc content without influencing calcium incorporation. All three metal ions were released into supernatants upon swelling aerogels in aqueous solutions, comparable to those measured for common wound dressings in human and animal injury models. The in vitro bioactivity studies showed that Zn-enriched swelling supernatants were able to suppress NO production in stimulated RAW 264.7 macrophages, indicating an effective anti-inflammatory activity.

The plant-specific calcium binding protein CAS (calcium sensor) has been localized in chloroplast thylakoid membranes of vascular plants and green algae. To elucidate the function of CAS in Chlamydomonas reinhardtii, we generated and analyzed eight independent CAS knockdown C. reinhardtii lines (cas-kd). Upon transfer to high-light (HL) growth conditions, cas-kd lines were unable to properly induce the expression of LHCSR3 protein that is crucial for nonphotochemical quenching. Prolonged exposure to HL revealed a severe light sensitivity of cas-kd lines and caused diminished activity and recovery of photosystem II (PSII). Remarkably, the induction of LHCSR3, the growth of cas-kd lines under HL, and the performance of PSII were fully rescued by increasing the calcium concentration in the growth media. Moreover, perturbing cellular Ca2+ homeostasis by application of the calmodulin antagonist W7 or the G-protein activator mastoparan impaired the induction of LHCSR3 expression in a concentration-dependent manner. Our findings demonstrate that CAS and Ca2+ are critically involved in the regulation of the HL response and particularly in the control of LHCSR3 expression.