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- Research DataSwitching Shapes: Reversible Three Species Photoisomerization of Substituted 1,2-Dihydro-1,2-azaborinines2026-02-09Derivatives of 1,2-dihydro-1,2-azaborinines generally undergo selective photochemical electrocyclic ring-closure reactions to the corresponding Dewar isomers (2-aza-3-borabicyclo[2.2.0]hex-5-ene). Depending on the substitution pattern, these photoreactions can also yield benzvalene (3-aza-4-boratricyclo[3.1.0.02.6]hexane) analogues. Here, we report the synthesis of 1,2,3,5-tetrasubstituted dihydroazaborinines by transition-metal-catalyzed late-stage functionalization and the investigation of their photophysical and photochemical properties using transient absorption spectroscopy. The introduction of aryl groups at the 3- and 5-positions induces a pronounced bathochromic shift of the absorption maximum. Under broad-spectrum irradiation (280–400 nm), quantitative conversion to the benzvalene isomer can be achieved. The initial photoisomerization proceeds via excitation to the short-lived singlet excited state (S1) yielding the Dewar isomer, whereas the subsequent conversion of this intermediate occurs through a long-lived excited state. Notably, the second isomerization step is accompanied by an interchange of the carbons C3 and C4. Once formed, the benzvalene isomers exhibit exceptional thermal stability. Cycloreversion to the Dewar isomer and even to the dihydroazaborinine structure can be triggered photochemically through targeted excitation and during both processes the substituents return to the C3 and C5 positions. The thermal cycloreversion of the benzvalene isomer can yield either the educt BN-benzene isomer (1,2,3,5-substitued) or its 1,2,4,5-substituted isomer. Computational studies revealed a stepwise mechanism for the thermal back reaction reforming the educt, while a concerted, energetically less-favorable pathway leads to the 1,2,4,5-substituted analogue.
5 1 - Research DataProkaryotic (6-4) photolyases depend on a one-way bridge for blue-light triggered electron transfer2026-04-07Flavin-dependent enzymes, such as photolyases and cryptochromes, harness blue light to drive photoreduction for the repair of UV-damaged DNA and signaling. Here, we investigate the photoreduction dynamics and protonation pathways of the prokaryotic 6-4 photolyase from Caulobacter crescentus (Cc(6-4)) using ultrafast UV/Vis spectroscopy, X-ray crystallography and molecular dynamics. The Cc(6-4) absorption spectrum is dominated by its three cofactors: FAD, an [4Fe-4S]2+ cluster, and DLZ. FAD photoreduction proceeds via a super-exchange mechanism, with tyrosine serving as primary electron bridge, facilitating forward electron transfer from a tryptophan, the second residue in the highly conserved electron transfer triad. Protonation, crucial for stabilizing the reduced FAD•−, is mediated by residue E402 and a nearby water molecule. Mutagenesis of this residue to glutamine blocks protonation, highlighting its critical role. Finally, the photochemical activity of the [4Fe-4S] cluster is reflected by sub-picosecond oxidation thus making the cluster to a second light-driven electron injector besides the fully reduced flavin cofactor. Given the absence of an ultimate electron acceptor, this cluster undergoes fast recombination within 1.5 ps. Overall, prokaryotic (6-4) photolyases depend for forward, but not backward electron transfer on a unique arrangement of the proximal aromatic residue allowing super-exchange, while protonation of the FAD•− state requires a transient protonation pathway.
9 - Research DataGrowth-Controlled Twinning and Magnetic Anisotropy in CeSb22026-03-13Cerium diantimonide (CeSb2) is a layered heavy-fermion Kondo lattice material that hosts complex magnetism and pressure-induced superconductivity. The interpretation of its in-plane anisotropy has remained unsettled due to structural twinning, which superimposes orthogonal magnetic responses. Here we combine controlled crystal growth with magnetization and rotational magnetometry to disentangle the effects of twinning. Nearly untwinned high-quality single crystals reveal the intrinsic in-plane anisotropy: the in-plane easy axis saturates at M_easy(4 T) ≈ 1.8 µ_B/Ce, while the in-plane hard axis magnetization is strongly suppressed, nearly linear, and comparable to the out-of-plane response. These results resolve long-standing discrepancies in reported magnetic measurements, in which in-plane metamagnetic transition fields and saturation magnetization varied significantly across previous studies. Growth experiments demonstrate that avoiding the proposed α-β structural transition - through Sb-rich flux and slower cooling - systematically reduces twinning. However, powder X-ray diffraction and differential thermal analysis measurements show no clear evidence of a distinct β phase. Our results establish a consistent magnetic phase diagram and provide essential constraints for crystal-electric field models, enabling a clearer understanding of the interplay between anisotropic magnetism and unconventional superconductivity in CeSb2.
29 1 - Research DataInhibition of the neurodevelopmental disorder-associated 16p11.2 gene QPRT leads to altered cell type distribution in human stem cell-derived cerebral organoids2026-03-11The 16p11.2 gene QPRT, encoding a key enzyme of the kynurenine pathway, has been linked to neurodevelopmental disorders including autism spectrum disorder (ASD). To investigate its role in early human brain development, we inhibited QPRT in stem cell-derived cerebral organoids. QPRT inhibition resulted in reduced organoid size, driven by premature neural differentiation resulting in depleted progenitor populations. Single-cell transcriptomics revealed an excitation/inhibition imbalance, with reduced excitatory and increased inhibitory neuron populations. We observed metabolic stress signatures, including pseudo-hypoxia, oxidative stress, and mitochondrial dysfunction, likely linked to NAD⁺ depletion and QUIN accumulation following QPRT inhibition. Notably, downregulation of LHX2 and PRDX1 may underlie impaired neural patterning and excitotoxic vulnerability. In addition, we report astrocytic and radial glia dysfunctions, indicating broad effects across multiple cell types. Disease gene enrichment analyses showed significant overlap with ASD-associated genes, especially during early differentiation. These findings suggest the loss or reduction of QPRT to shift neural development and neuronal homeostasis towards an imbalance in excitatory and inhibitory neuronal populations, a mechanism previously associated with neurodevelopmental disorders. Prepublication of the main manuscript is available at bioRxiv https://doi.org/10.1101/2025.09.08.673916
29 10 - Research DataTwo distinct modes of Vgll4-mediated Tead regulation control organ size in zebrafish - SourceData2026-03-19Control of organ size during development and homeostasis relies on balanced regulation of Hippo pathway transcriptional output, yet how TEAD activity is precisely regulated in vivo remains unclear. Using the zebrafish posterior lateral line (pLL) we show that Yap1 is required early in pLL progenitors to ensure sufficient cell numbers in the migrating primordium. In contrast, the two zebrafish Vgll4 paralogs, Vgll4b and Vgll4l, act partially redundantly to limit pLLP size and cell number. Through loss- and gain-of-function analyses, epistasis experiments, transcriptional reporter quantification and pharmacological treatments, we find that Vgll4 restricts Tead-dependent transcription through two co-existing mechanisms: inhibition of Yap1–Tead–mediated transcriptional activation and Tead-dependent repression. Together, our findings reconcile the competitive and default repression models of VGLL4 function and provide an integrated framework for how VGLL4 fine-tunes TEAD output to control tissue growth in vivo.
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- Research DataThe global water resources and use model WaterGAP v2.2e - model output driven by gswp3-w5e5 and historical setup of direct human impacts2023-10-20Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download model output for the time period 1901-2019 that was computed by driving WaterGAP v2.2e by four alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. For two climate datasets, model runs up to 2021 or 2022 are available. For comparison, output of a version of WaterGAP v2.2d that is calibrated to the same dataset of observed streamflow as WaterGAP v2.2e is provided. Each of the climate forcing-model version combinations is run in two socio-economic settings, histsoc and nosoc. In nosoc, human water use is set to zero and man-made reservoirs are assumed to be non-existant. In the paper connected to this dataset (to be submitted to Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. The most important and requested model outputs (total water storage variations, streamflow and water use) are evaluated against observation data. Standard model output is described as well as the specifics of the WaterGAP contribution within the ISIMIP framework. Müller Schmied, H., Cáceres, D., Eisner, S., Flörke, M., Herbert, C., Niemann, C., Peiris, T. A., Popat, E., Portmann, F. T., Reinecke, R., Schumacher, M., Shadkam, S., Telteu, C.-E., Trautmann, T., Döll, P. (2021): The global water resources and use model WaterGAP v2.2d: Model description and evaluation. Geosci. Model Dev., 14, 1037–1079. https://doi.org/10.5194/gmd-14-1037-2021
1456 981 - Research DataThe global water resources and use model WaterGAP v2.2e - model output driven by gswp3-era5 and historical setup of direct human impacts2023-10-20Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download model output for the time period 1901-2019 that was computed by driving WaterGAP v2.2e by four alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. For two climate datasets, model runs up to 2021 or 2023 are available. For comparison, output of a version of WaterGAP v2.2d that is calibrated to the same dataset of observed streamflow as WaterGAP v2.2e is provided. Each of the climate forcing-model version combinations is run in two socio-economic settings, histsoc and nosoc. In nosoc, human water use is set to zero and man-made reservoirs are assumed to be non-existant. In the paper connected to this dataset (in review with Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. The most important and requested model outputs (total water storage variations, streamflow and water use) are evaluated against observation data. Standard model output is described as well as the specifics of the WaterGAP contribution within the ISIMIP framework. Müller Schmied, H., Cáceres, D., Eisner, S., Flörke, M., Herbert, C., Niemann, C., Peiris, T. A., Popat, E., Portmann, F. T., Reinecke, R., Schumacher, M., Shadkam, S., Telteu, C.-E., Trautmann, T., Döll, P. (2021): The global water resources and use model WaterGAP v2.2d: Model description and evaluation. Geosci. Model Dev., 14, 1037–1079. https://doi.org/10.5194/gmd-14-1037-2021
903 963 - Research DataThe global water resources and use model WaterGAP v2.2e - daily water storage model output driven by gswp3-era5 and historical setup of direct human impacts2024-04-04Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download daily model output for water storage variables for the time period 1901-2019 (2023) that was computed by driving WaterGAP v2.2e by two alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. In the paper connected to this dataset (in review with Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. Here, the single water storage compartments and terrestrial (total) water storage are provided.
402 306 - Research DataA j_eff 12 Kitaev material on the triangular lattice: The case of NaRuO22023-06-07Motivated by recent reports of a quantum disordered ground state in the triangular lattice compound NaRuO$_2$, we derive a $j_{\rm eff}=1/2$ magnetic model for this system by means of first-principles calculations. The pseudospin Hamiltonian is dominated by bond-dependent off-diagonal $\Gamma$ interactions, complemented by a ferromagnetic Heisenberg exchange and a notably \emph{antiferromagnetic} Kitaev term. In addition to bilinear interactions, we find a sizable four-spin ring exchange contribution with a \emph{strongly anisotropic} character, which has been so far overlooked when modeling Kitaev materials. The analysis of the magnetic model, based on the minimization of the classical energy and exact diagonalization of the quantum Hamiltonian, points toward the existence of a rather robust easy-plane ferromagnetic order, which cannot be easily destabilized by physically relevant perturbations.
370 40 - Research DataClimate forcing GSWP3-ERA5 as input for the global hydrological model WaterGAP2024-06-19This dataset contains the climate data for the 4 variables (pr, tas, rsds, rlds) to run the Python-Version of WaterGAP. For details please see the ReWaterGAP documentation (https://hydrologyfrankfurt.github.io/ReWaterGAP/).
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