Archimedean-like colloidal tilings on substrates with decagonal and tetradecagonal symmetry

Two-dimensional colloidal suspensions subject to laser interference patterns with decagonal symmetry can form an Archimedean-like tiling phase where rows of squares and triangles order aperiodically along one direction [J. Mikhael et al., Nature 454, 501 (2008)]. In experiments as well as in Monte-Carlo and Brownian dynamics simulations, we identify a similar phase when the laser field possesses tetradecagonal symmetry. We characterize the structure of both Archimedean-like tilings in detail and point out how the tilings differ from each other. Furthermore, we also estimate specific particle densities where the Archimedean-like tiling phases occur. Finally, using Brownian dynamics simulations we demonstrate how phasonic distortions of the decagonal laser field influence the Archimedean-like tiling. In particular, the domain size of the tiling can be enlarged by phasonic drifts and constant gradients in the phasonic displacement. We demonstrate that the latter occurs when the interfering laser beams are not adjusted properly

Rethinking ‘top‐down’ and ‘bottom‐up’ roles of top and middle managers in organizational change: implications for employee support

In this study we integrate insights from ‘top‐down’ and ‘bottom‐up’ traditions in organizational change research to understand employees’ varying dispositions to support change. We distinguish between change initiation and change execution roles and identify four possible role configurations in which top managers (TMs) and middle managers (MMs) can feature in change. We contend that both TMs and MMs can play change initiation and/or change execution roles, TMs and MMs have different strengths and limitations for taking on different change roles, and their relative strengths and limitations are compounded or attenuated based on the specific configuration of change roles. We subsequently hypothesize employee support for change in relation to different TM‐MM change role configurations. Our findings show that change initiated by TMs does not engender above‐average level of employee support. However, change initiated by MMs engenders above‐average level of employee support, and even more so, if TMs handle the change execution

Single-Nucleus RNA-Seq Is Not Suitable for Detection of Microglial Activation Genes in Humans

Single-nucleus RNA sequencing (snRNA-seq) is used as an alternative to single-cell RNA-seq, as it allows transcriptomic profiling of frozen tissue. However, it is unclear whether snRNA-seq is able to detect cellular state in human tissue. Indeed, snRNA-seq analyses of human brain samples have failed to detect a consistent microglial activation signature in Alzheimer's disease. Our comparison of microglia from single cells and single nuclei of four human subjects reveals that, although most genes show similar relative abundances in cells and nuclei, a small population of genes (∼1%) is depleted in nuclei compared to whole cells. This population is enriched for genes previously implicated in microglial activation, including APOE, CST3, SPP1, and CD74, comprising 18% of previously identified microglial-disease-associated genes. Given the low sensitivity of snRNA-seq to detect many activation genes, we conclude that snRNA-seq is not suited for detecting cellular activation in microglia in human disease

microRNA-132 regulates adult neural stem cells and their progeny to restore hippocampal neurogenesis and memory in Alzheimer’s disease

Neural stem cells residing in the hippocampal neurogenic niche sustain life-long neurogenesis in the adult brain. Adult hippocampal neurogenesis (AHN) is functionally linked to mnemonic and cognitive plasticity in humans and rodents. In Alzheimer’s disease (AD), the process of generating new neurons at the hippocampal neurogenic niche is impeded, yet the mechanisms involved are unknown. Here we identify miR-132, one of the most consistently downregulated microRNAs in AD, as a potent regulator of AHN, exerting cell-autonomous pro-neurogenic effects in the adult neural stem cells and their progeny. Using distinct AD mouse models, cultured human primary and established neural stem cells, and human patient material, we demonstrate that AHN is directly impacted by AD pathology. miR-132 replacement in adult mouse AD hippocampus restores AHN and relevant memory deficits. Our findings corroborate the significance of AHN in AD and reveal the possible therapeutic potential of targeting miR-132 in neurodegeneration.<br/