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Abstract Chromium(III)-trisoxalate, [Cr(ox) 3 ] 3− (ox=C 2 O 4 2− ), incorporated into polymeric networks of composition [NaCr(ox) 3 ][M II (bpy) 3 ] and [NaCr(ox) 3 ][M III (bpy) 3 ]ClO 4 (ox=C 2 O 4 2− , bpy=2,2′-bipyridine, M II =Zn, Fe, Ru; M III =Rh, Cr), results in interesting features ranging from phonon-assisted and resonant energy migration within the R 1 line the 2 E state to persistent spectral side-hole burning via the latter, and manifestations of specific nearest-neighbour π – π interactions between bipyridine and oxalate.

Abstract Chromium(III)-trisoxalate, [Cr(ox) 3 ] 3− (ox=C 2 O 4 2− ), incorporated into polymeric networks of composition [NaCr(ox) 3 ][M II (bpy) 3 ] and [NaCr(ox) 3 ][M III (bpy) 3 ]ClO 4 (ox=C 2 O 4 2− , bpy=2,2′-bipyridine, M II =Zn, Fe, Ru; M III =Rh, Cr), results in interesting features ranging from phonon-assisted and resonant energy migration within the R 1 line the 2 E state to persistent spectral side-hole burning via the latter, and manifestations of specific nearest-neighbour π – π interactions between bipyridine and oxalate.

Nucleotides are key players in the central energy metabolism of cells. Here we show how to estimate the energy charge from cell lysates by direct negative ion matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using 9-aminoacridine as matrix. We found a high level of in-source decay of all the phosphorylated nucleotides, with some of them producing considerable amounts of adenosine-5'-diphosphate (ADP) fragment ions. We investigated the behavior of adenosine-5'-monophosphate (AMP), ADP, and adenosine-5'-triphosphate (ATP) as well as the cofactors coenzyme A (CoA) and acetyl-coenzyme A (ACoA) and nicotinamide adenine dinucleotides (NAD⁺ and NADH) in detail. In-source decay of these compounds depends strongly on the applied laser power and on the extraction pulse delay. At standard instrument settings, the 9-aminoacridine (9-AA) matrix resulted in a much higher in-source decay compared with 2,4,6-trihydroxyacetophenone (2,4,6-THAP). By adding ¹³C-labeled ATP to a cell lysate, we were able to determine the degree of in-source decay during an experiment. Analyzing a cell extract of the monocytic cell line THP-1 with [¹³C]ATP as internal standard, we were able to obtain values for the energy charge that were similar to those determined by a reference liquid chromatography electrospray ionization coupled to mass spectrometry (LC-ESI-MS) method.

Nucleotides are key players in the central energy metabolism of cells. Here we show how to estimate the energy charge from cell lysates by direct negative ion matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using 9-aminoacridine as matrix. We found a high level of in-source decay of all the phosphorylated nucleotides, with some of them producing considerable amounts of adenosine-5'-diphosphate (ADP) fragment ions. We investigated the behavior of adenosine-5'-monophosphate (AMP), ADP, and adenosine-5'-triphosphate (ATP) as well as the cofactors coenzyme A (CoA) and acetyl-coenzyme A (ACoA) and nicotinamide adenine dinucleotides (NAD⁺ and NADH) in detail. In-source decay of these compounds depends strongly on the applied laser power and on the extraction pulse delay. At standard instrument settings, the 9-aminoacridine (9-AA) matrix resulted in a much higher in-source decay compared with 2,4,6-trihydroxyacetophenone (2,4,6-THAP). By adding ¹³C-labeled ATP to a cell lysate, we were able to determine the degree of in-source decay during an experiment. Analyzing a cell extract of the monocytic cell line THP-1 with [¹³C]ATP as internal standard, we were able to obtain values for the energy charge that were similar to those determined by a reference liquid chromatography electrospray ionization coupled to mass spectrometry (LC-ESI-MS) method.

ABSTRACTThe primary production of fjords across the Arctic and Subarctic is undergoing significant transformations due to the climatically driven retreat of glaciers and ice sheets. However, the implications of these changes for upper trophic levels remain largely unknown. In this study, we employ both bulk and compound‐specific stable isotope analyses to investigate how shifts at the base of fjord food webs impact the carbon and energy sources of consumers. Focusing on two rapidly changing fjords in Southern Greenland, we used the migratory Arctic char as an indicator species, sampling populations along environmental gradients within the fjords, building upon the assumption that char populations feed primarily close to their natal stream, thereby integrating a dietary gradient. Our analysis of bulk stable isotopes in Arctic char tissue confirmed this premise, revealing a consistent change in resource use from the outer to the inner fjord, which nonetheless served as preferred feeding grounds. Essential amino acid analysis further indicated shifts in carbon and nitrogen sources, consistent with changes in nutrient use near glacier inputs characterized by low turbidity and high iron levels. Notably, these changes in the source of primary production were associated with shifts in trophic positions and the transfer of polyunsaturated fatty acids, with Arctic char in glacier‐influenced inner fjords feeding at lower trophic level (size‐corrected) and accumulating higher levels of high‐quality docosahexaenoic acid (DHA). These findings highlight the usefulness of new analytical tools in revealing that glacial retreat can substantially alter food web dynamics, enhancing both carbon flow and the nutritional quality of fish in fjord ecosystems. The two Southern Greenland fjords studied could represent the future of other fjords, where retreating glaciers become land‐terminating and glacial inputs decrease. Our study underscores the critical role of glacier dynamics in affecting high‐level consumers, such as salmonids, with implications for fjords globally.

ABSTRACTThe primary production of fjords across the Arctic and Subarctic is undergoing significant transformations due to the climatically driven retreat of glaciers and ice sheets. However, the implications of these changes for upper trophic levels remain largely unknown. In this study, we employ both bulk and compound‐specific stable isotope analyses to investigate how shifts at the base of fjord food webs impact the carbon and energy sources of consumers. Focusing on two rapidly changing fjords in Southern Greenland, we used the migratory Arctic char as an indicator species, sampling populations along environmental gradients within the fjords, building upon the assumption that char populations feed primarily close to their natal stream, thereby integrating a dietary gradient. Our analysis of bulk stable isotopes in Arctic char tissue confirmed this premise, revealing a consistent change in resource use from the outer to the inner fjord, which nonetheless served as preferred feeding grounds. Essential amino acid analysis further indicated shifts in carbon and nitrogen sources, consistent with changes in nutrient use near glacier inputs characterized by low turbidity and high iron levels. Notably, these changes in the source of primary production were associated with shifts in trophic positions and the transfer of polyunsaturated fatty acids, with Arctic char in glacier‐influenced inner fjords feeding at lower trophic level (size‐corrected) and accumulating higher levels of high‐quality docosahexaenoic acid (DHA). These findings highlight the usefulness of new analytical tools in revealing that glacial retreat can substantially alter food web dynamics, enhancing both carbon flow and the nutritional quality of fish in fjord ecosystems. The two Southern Greenland fjords studied could represent the future of other fjords, where retreating glaciers become land‐terminating and glacial inputs decrease. Our study underscores the critical role of glacier dynamics in affecting high‐level consumers, such as salmonids, with implications for fjords globally.

Abstract This paper discusses the impact of bulk electric storage on the production from dispatchable power plants for rising variable renewable electricity shares. Two complementary optimization frameworks are used to represent power systems with a varying degree of complexity. The corresponding models approximate the wholesale electricity market, combined with the rational retirement of dispatchable capacity. Two different generic storage technologies are introduced exogenously to assess their impact on the system. The analysis covers two countries: France, where the power supply’s large nuclear share allows for the discussion of storage impact on a single generator type; and Germany, whose diverse power supply structure enables storage interactions with multiple electricity generators. In the most general case, additional storage capacity increases dispatchable power production (e.g. nuclear, coal) for small wind and solar shares, i.e. it compensates the replacement induced by renewable energies. For larger variable renewable electricity volumes, it actively contributes to dispatchable power replacement. In a diverse power system, this results in storage-induced sequential mutual replacements of power generation from different plant types, as wind and solar capacities are increased. This mechanism is strongly dependent on the technical parameters of the storage assets. As a result, the impact of different storage types can have opposite signs under certain circumstances. The influence of CO2 emission prices, wind and solar profile shapes, and power plant ramping costs is discussed.

Abstract This paper discusses the impact of bulk electric storage on the production from dispatchable power plants for rising variable renewable electricity shares. Two complementary optimization frameworks are used to represent power systems with a varying degree of complexity. The corresponding models approximate the wholesale electricity market, combined with the rational retirement of dispatchable capacity. Two different generic storage technologies are introduced exogenously to assess their impact on the system. The analysis covers two countries: France, where the power supply’s large nuclear share allows for the discussion of storage impact on a single generator type; and Germany, whose diverse power supply structure enables storage interactions with multiple electricity generators. In the most general case, additional storage capacity increases dispatchable power production (e.g. nuclear, coal) for small wind and solar shares, i.e. it compensates the replacement induced by renewable energies. For larger variable renewable electricity volumes, it actively contributes to dispatchable power replacement. In a diverse power system, this results in storage-induced sequential mutual replacements of power generation from different plant types, as wind and solar capacities are increased. This mechanism is strongly dependent on the technical parameters of the storage assets. As a result, the impact of different storage types can have opposite signs under certain circumstances. The influence of CO2 emission prices, wind and solar profile shapes, and power plant ramping costs is discussed.