Tuning the ferrotoroidic coupling and magnetic hysteresis in double-triangle complexes {Dy3MIIIDy3} via the MIII-linker

We present the syntheses, structures, magnetic data and theoretical analyses for two families of heptanuclear clusters, wherein two staggered dysprosium(III) triangles are linked by various M(III) d‐/p‐block ions. The families differ in the counter‐anion and are of formulae [DyIII6MIII(OH)8(o‐tol)12(MeOH)5(NO3)]∙4MeOH and [DyIII6MIII(OH)8(o‐tol)12(MeOH)6]Cl·6MeOH (M = Cr, Mn, Fe, Co, Al; o‐tol = o‐toluate). We find that variation of the central metal ion M is crucial in tuning the toroidal moments on the triangular units, with diamagnetic M linking ions enhancing the ferrotoroidic coupling. By detailed simulation and analysis of various magnetic measurements, including sub‐kelvin microSquid hysteresis loops, we identified the specific signature of the M linking ions’ modulation of toroidal properties, including the mechanism whereby anisotropic, paramagnetic M ions lead to hysteresis profiles with larger remnant magnetisations and broader coercive fields

Capase-2 is required for cell death induced by cytoskeletal disruption

Caspase-2 is one of the most conserved caspases, yet its biological function remains a matter of controversy. In the present article we analysed mouse embryonic fibroblasts (MEFs) from caspase-2 knockout mice for their sensitivity to various apoptosis inducing agents. We found that cell death induced by drugs that disrupt cytoskeleton is significantly inhibited in Casp2- /- MEFs. These drugs included zoledronic acid, vincristine, cytochalasin D and paclitaxel. We demonstrate that MEFs lacking Casp2 show clonogenic survival following drug treatment, whereas all Casp2+/+ MEFs die, indicating that caspase-2 is required for apoptosis induced by cytoskeletal disruption. We further found that caspase-2 mediates apoptosis via Piddosome, Bid and Bax activation, and cytochrome c release. In the absence of caspase-2, Bid and Bax activation, and cytochrome c release are significantly delayed following drug treatment. Our data provide strong support for a context-dependent function of caspase-2 in apoptosis.L H Ho, S H Read, L Dorstyn, L Lambrusco and S Kumar