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Early transition metal alkyl and hydride complexes have been widely explored for their propensity to faciltate C–H activation through a concerted σ-bond metathesis mechanism. Herein, we report the synthesis of a tris(amido) Zr(IV) alkyl complex 1 as a precursor of accessing a proposed transient Zr(IV)-hydride. Upon intramolecular C–H activation of a pendent methyl group, a strained cyclometalated complex 2 is obtained. Relief of ring strain and cooperative metal–ligand C–H activation provided access to Zr-acetylide complex 3, which is capable of undergoing insertion reactivity into carbonyl containing compounds, like aldehydes and ketones. Complexes 1–3 are characterized using multinuclear NMR spectroscopy, UV–vis spectroscopy, and X-ray crystallography. Newly reported electron-rich propargylic alcohols 6 and 7 are isolated and fully characterized using multinuclear NMR spectroscopy, ESI-MS, and FTIR. 

Nanoindentation was performed on individual grains of a polycrystalline Mg sample with c-axis declination angles ranging from parallel (0°) to perpendicular (90°) to the c-axis. Hardness was highest at ∼0°, decreased up to ∼55°, and then increased at ∼90° to an intermediate level. At ∼0°, high-density 〈c + a〉 dislocations extended deep into the crystal, contributing to high hardness. At ∼55°, 〈c + a〉 dislocations were confined near the indent, and occasional extension twinning reoriented the crystal to ∼45°, promoting 〈a〉 slip in both matrix and twin, leading to low hardness. At ∼90°, extension twinning reoriented the crystal to ∼0°, inducing texture hardening and intermediate hardness. Despite the complex stress state in nanoindentation, which fundamentally differs from the uniaxial stress in bulk tensile and compression tests, the combined contributions of dislocation and twinning still give rise to measurable hardness anisotropy, suggesting nanoindentation as a high-throughput technique for probing orientation-dependent mechanical behavior in Mg. 

The indirect detection of dark matter (DM) through its annihilation products is one of the primary strategies for DM detection. One of the least constrained classes of models is neutrinophilic DM, because the annihilation products, weakly interacting neutrinos, are challenging to observe. Here, we consider a scenario where MeV-mass DM exclusively annihilates to the third neutrino mass eigenstate, which is predominantly of tau and muon flavor. In such a scenario, the potential detection rate of the neutrinos originating from the DM annihilation in our Galaxy in the conventional detectors would be suppressed by up to approximately two orders of magnitude. This is because the best sensitivity of such detectors for neutrinos with energies below approximately 100 MeV is for electron neutrino flavor. In this work, we highlight the potential of large-scale DM detectors in uncovering such signals in the tens of MeV range of DM masses. In addition, we discuss how coincident signals in direct detection DM experiments and upcoming neutrino detectors such as DUNE, Hyper-Kamiokande, and JUNO could provide new perspectives on the DM problem. Published by the American Physical Society2025 

A non-isocyanate synthetic route was used to generate 20 different ionic liquids containing either a carbamate or thiocarbamate functional group. 

We calculate the extent to which collisionless dark matter impacts the stability of supermassive stars (M>10^4 solar masses). We find that, depending on the star’s mass, a dark matter content in excess of ~ 1% by mass throughout the entire star can raise the critical central density for the onset of general relativistic instability, in some cases by orders of magnitude. We consider implications of this effect for the onset of nuclear burning and significant neutrino energy losses. 

We present a mechanism for producing a cosmologically significant relic density of one or more sterile neutrinos. This scheme invokes two steps: First, a population of “heavy” sterile neutrinos is created by scattering-induced decoherence of active neutrinos. Second, this population is transferred, via sterile neutrino self-interaction-mediated scatterings and decays, to one or more lighter mass ( $\sim 10\mathrm{keV}$to $\sim 1\mathrm{GeV}$) sterile neutrinos that are far more weakly (or not at all) mixed with active species and could constitute dark matter. Dark matter produced this way can evade current electromagnetic and structure-based bounds, but may nevertheless be probed by future observations. Published by the American Physical Society2024 

Abstract Understanding healthy human brain function is crucial to identify and map pathological tissue within it. Whilst previous studies have mapped intracranial EEG (icEEG) from non-epileptogenic brain regions, they often neglect age and sex effects. Further, they are limited by small sample sizes due to the modality’s invasive nature. This study substantially expands the subject pool compared to existing literature, to create a multi-centre, normative map of brain activity which considers the effects of age, sex and recording hospital. Using interictal icEEG recordings from$$n = 502$$subjects across 15 centres, we constructed a normative map of non-pathological brain activity by regressing age and sex on relative band power in five frequency bands. A linear mixed model was implemented to account for the hospital effect. Variable importance was assessed using standard statistical measures, and regression coefficients (and their standard errors) were analysed at both whole-brain and regional scales. Recording hospital significantly impacted normative icEEG maps in all frequency bands, and age was a more influential predictor of band power than sex. The age effect varied by frequency band, but no spatial patterns were observed at the region-specific level. Certainty about regression coefficients was also frequency band specific and moderately impacted by sample size. The concept of a normative map is well-established in neuroscience research and particularly relevant to the icEEG modality, which does not allow healthy control baselines. Our key results regarding the hospital site and age effect guide future work utilising normative maps in icEEG.