@article{8597, abstract = {Error analysis and data visualization of positive COVID-19 cases in 27 countries have been performed up to August 8, 2020. This survey generally observes a progression from early exponential growth transitioning to an intermediate power-law growth phase, as recently suggested by Ziff and Ziff. The occurrence of logistic growth after the power-law phase with lockdowns or social distancing may be described as an effect of avoidance. A visualization of the power-law growth exponent over short time windows is qualitatively similar to the Bhatia visualization for pandemic progression. Visualizations like these can indicate the onset of second waves and may influence social policy.}, author = {Merrin, Jack}, issn = {14783975}, journal = {Physical Biology}, number = {6}, publisher = {IOP Publishing}, title = {{Differences in power law growth over time and indicators of COVID-19 pandemic progression worldwide}}, doi = {10.1088/1478-3975/abb2db}, volume = {17}, year = {2020}, } @article{8674, abstract = {Extrasynaptic actions of glutamate are limited by high-affinity transporters expressed by perisynaptic astroglial processes (PAPs): this helps maintain point-to-point transmission in excitatory circuits. Memory formation in the brain is associated with synaptic remodeling, but how this affects PAPs and therefore extrasynaptic glutamate actions is poorly understood. Here, we used advanced imaging methods, in situ and in vivo, to find that a classical synaptic memory mechanism, long-term potentiation (LTP), triggers withdrawal of PAPs from potentiated synapses. Optical glutamate sensors combined with patch-clamp and 3D molecular localization reveal that LTP induction thus prompts spatial retreat of astroglial glutamate transporters, boosting glutamate spillover and NMDA-receptor-mediated inter-synaptic cross-talk. The LTP-triggered PAP withdrawal involves NKCC1 transporters and the actin-controlling protein cofilin but does not depend on major Ca2+-dependent cascades in astrocytes. We have therefore uncovered a mechanism by which a memory trace at one synapse could alter signal handling by multiple neighboring connections.}, author = {Henneberger, Christian and Bard, Lucie and Panatier, Aude and Reynolds, James P. and Kopach, Olga and Medvedev, Nikolay I. and Minge, Daniel and Herde, Michel K. and Anders, Stefanie and Kraev, Igor and Heller, Janosch P. and Rama, Sylvain and Zheng, Kaiyu and Jensen, Thomas P. and Sanchez-Romero, Inmaculada and Jackson, Colin J. and Janovjak, Harald L and Ottersen, Ole Petter and Nagelhus, Erlend Arnulf and Oliet, Stephane H.R. and Stewart, Michael G. and Nägerl, U. VAlentin and Rusakov, Dmitri A. }, issn = {10974199}, journal = {Neuron}, number = {5}, pages = {P919--936.E11}, publisher = {Elsevier}, title = {{LTP induction boosts glutamate spillover by driving withdrawal of perisynaptic astroglia}}, doi = {10.1016/j.neuron.2020.08.030}, volume = {108}, year = {2020}, } @article{8652, abstract = {Nature creates electrons with two values of the spin projection quantum number. In certain applications, it is important to filter electrons with one spin projection from the rest. Such filtering is not trivial, since spin-dependent interactions are often weak, and cannot lead to any substantial effect. Here we propose an efficient spin filter based upon scattering from a two-dimensional crystal, which is made of aligned point magnets. The polarization of the outgoing electron flux is controlled by the crystal, and reaches maximum at specific values of the parameters. In our scheme, polarization increase is accompanied by higher reflectivity of the crystal. High transmission is feasible in scattering from a quantum cavity made of two crystals. Our findings can be used for studies of low-energy spin-dependent scattering from two-dimensional ordered structures made of magnetic atoms or aligned chiral molecules.}, author = {Ghazaryan, Areg and Lemeshko, Mikhail and Volosniev, Artem}, issn = {2399-3650}, journal = {Communications Physics}, publisher = {Springer Nature}, title = {{Filtering spins by scattering from a lattice of point magnets}}, doi = {10.1038/s42005-020-00445-8}, volume = {3}, year = {2020}, } @article{8669, abstract = {Pancreatic islets play an essential role in regulating blood glucose level. Although the molecular pathways underlying islet cell differentiation are beginning to be resolved, the cellular basis of islet morphogenesis and fate allocation remain unclear. By combining unbiased and targeted lineage tracing, we address the events leading to islet formation in the mouse. From the statistical analysis of clones induced at multiple embryonic timepoints, here we show that, during the secondary transition, islet formation involves the aggregation of multiple equipotent endocrine progenitors that transition from a phase of stochastic amplification by cell division into a phase of sublineage restriction and limited islet fission. Together, these results explain quantitatively the heterogeneous size distribution and degree of polyclonality of maturing islets, as well as dispersion of progenitors within and between islets. Further, our results show that, during the secondary transition, α- and β-cells are generated in a contemporary manner. Together, these findings provide insight into the cellular basis of islet development.}, author = {Sznurkowska, Magdalena K. and Hannezo, Edouard B and Azzarelli, Roberta and Chatzeli, Lemonia and Ikeda, Tatsuro and Yoshida, Shosei and Philpott, Anna and Simons, Benjamin D}, issn = {20411723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Tracing the cellular basis of islet specification in mouse pancreas}}, doi = {10.1038/s41467-020-18837-3}, volume = {11}, year = {2020}, } @article{8672, abstract = {Cell fate transitions are key to development and homeostasis. It is thus essential to understand the cellular mechanisms controlling fate transitions. Cell division has been implicated in fate decisions in many stem cell types, including neuronal and epithelial progenitors. In other stem cells, such as embryonic stem (ES) cells, the role of division remains unclear. Here, we show that exit from naive pluripotency in mouse ES cells generally occurs after a division. We further show that exit timing is strongly correlated between sister cells, which remain connected by cytoplasmic bridges long after division, and that bridge abscission progressively accelerates as cells exit naive pluripotency. Finally, interfering with abscission impairs naive pluripotency exit, and artificially inducing abscission accelerates it. Altogether, our data indicate that a switch in the division machinery leading to faster abscission regulates pluripotency exit. Our study identifies abscission as a key cellular process coupling cell division to fate transitions.}, author = {Chaigne, Agathe and Labouesse, Céline and White, Ian J. and Agnew, Meghan and Hannezo, Edouard B and Chalut, Kevin J. and Paluch, Ewa K.}, issn = {18781551}, journal = {Developmental Cell}, number = {2}, pages = {195--208}, publisher = {Elsevier}, title = {{Abscission couples cell division to embryonic stem cell fate}}, doi = {10.1016/j.devcel.2020.09.001}, volume = {55}, year = {2020}, }