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Ferrocenes were studied as cyclopentadiene ring surrogates enroute to non-metallocene targets such as the aminofulveno[1,2-b]chromone natural product chalaniline A. Ferroceno[b]chromone, as an archetype of interest, was prepared from ferrocenecarboxylic acid (4 steps, 24% yield) via N,N-diethyl 2-iodoferrocenecarboxamide by Ullmann etherification with phenol followed by LDA-mediated anionic cyclization. Reactivity studies revealed that this planar chiral analogue of xanthone readily fragments into non-metallocene products upon reaction with electrophiles. 1-Methoxy-3-methylferroceno[b]chromone, prepared similarly by substituting O-methylorcinol for phenol, was advanced to chalaniline A and a transposed regioisomer by concomitant deferration and demethylation with AlCl3; formylation of the resulting cyclopentadiene-fused chromone with excess Vilsmeier reagent; and then Pinnick oxidation (NaClO2), methylation (TMSCHN2), and final transamination (PhNH2). Four compounds, including ferroceno[b]chromone and the C11/C12-transposed regioisomer of chalaniline A, were characterized by single crystal X-ray diffraction analysis. 

PurposeThis study aims to introduce the University Handprint Framework – a novel method for quantifying the external positive impacts (“handprints”) of sustainability actions undertaken by higher education institutions. It aims to fill a critical gap in current sustainability tracking systems by enabling universities to measure their contributions to societal and environmental outcomes beyond campus boundaries. Design/methodology/approachThe study presents a case study of a project-based sustainability course that partnered students with external organizations to implement climate-related solutions. The study calculated the university’s potential handprint associated with the course and informed the development of the University Handprint Framework. Data challenges, such as availability, tracking, attribution and double counting of emissions, were addressed in the method’s development to ensure methodological rigor. FindingsThis study results revealed that the course enabled partner organizations to reduce greenhouse gas emissions by an estimated 7.04E + 05 kg CO2-eq, which demonstrated a quantifiable, university-enabled carbon handprint beyond campus boundaries. Practical implicationsThe framework offers universities a practical tool to highlight their broader societal contributions and can inform policy, reporting and investment in sustainability education and research. Given universities’ pivotal role in research dissemination, sustainability education and climate change mitigation, showcasing these positive impacts is essential. Originality/valueThis is the first known framework tailored to higher education that enables structured quantification of both potential (ex ante) and realized (ex-post) handprints. It complements existing tools and adds a new dimension to sustainability planning and impact tracking in academia. 

We derive the explicit embedding of the effective Kerr spacetimes, which are pertinent to the vanishing of static Love numbers, soft hair descriptions of Kerr black holes, and low-frequency scalar-Kerr scattering amplitudes, as solutions within $N=2$supergravity. These spacetimes exhibit a hidden $SL(2,R)\times U\left(1\right)$or $SO(4,2)$symmetry resembling the so called subtracted geometries with $SL(2,R)\times SL(2,R)$symmetry, which accurately represent the near-horizon geometry of Kerr black holes and, as we will argue most accurately represents the internal structure of the Kerr black hole. To quantify the differences among the effective Kerr spacetimes, we compare their physical quantities, internal structures, and geodesic equations. Although their thermodynamic properties, including entropy, match those of Kerr, our study uncovers significant differences in the interiors of these effective Kerr solutions. A careful examination of the internal structure of the spacetimes highlights the distinctions between various effective Kerr geometries and their quasinormal spectra. Published by the American Physical Society2025 

Abstract Sodium ions (Na⁺) are major charge carriers mediating neuronal excitation and play a fundamental role in brain physiology. Glutamatergic synaptic activity is accompanied by large transient Na⁺increases, but the spatio-temporal dynamics of Na⁺signals and properties of Na⁺diffusion within dendrites are largely unknown. To address these questions, we employed multi-photon Na⁺imaging combined with whole-cell patch-clamp in dendrites of CA1 pyramidal neurons in tissue slices from mice of both sexes. Fluorescence lifetime microscopy revealed a dendritic baseline Na⁺concentration of ~10 mM. Using intensity-based line-scan imaging we found that local, glutamate-evoked Na⁺signals spread rapidly within dendrites, with peak amplitudes decreasing and latencies increasing with increasing distance from the site of stimulation. Spread of Na⁺along dendrites was independent of dendrite diameter, order or overall spine density in the ranges measured. Our experiments also show that dendritic Na⁺readily invades spines and suggest that spine necks may represent a partial diffusion barrier. Experimental data were well reproduced by mathematical simulations assuming normal diffusion with a diffusion coefficient of. Modeling moreover revealed that lateral diffusion is key for the clearance of local Na⁺increases at early time points, whereas when diffusional gradients are diminished, Na⁺/K⁺-ATPase becomes more relevant. Taken together, our study thus demonstrates that Na⁺influx causes rapid lateral diffusion of Na⁺within spiny dendrites. This results in an efficient redistribution and fast recovery from local Na⁺transients which is mainly governed by concentration differences. Significance statementActivity of excitatory glutamatergic synapses generates large Na⁺transients in postsynaptic cells. Na⁺influx is a main driver of energy consumption and modulates cellular properties by modulating Na⁺-dependent transporters. Knowing the spatio-temporal dynamics of dendritic Na⁺signals is thus critical for understanding neuronal function. To study propagation of Na⁺signals within spiny dendrites, we performed fast Na⁺imaging combined with mathematical simulations. Our data shows that normal diffusion, based on a diffusion coefficient of 600 µm²/s, is crucial for fast clearance of local Na⁺transients in dendrites, whereas Na⁺export by the Na⁺/K⁺-ATPase becomes more relevant at later time points. This fast diffusive spread of Na⁺will reduce the local metabolic burden imposed by synaptic Na⁺influx.