@article{10116, abstract = {The ubiquitous Ca2+ sensor calmodulin (CaM) binds and regulates many proteins, including ion channels, CaM kinases, and calcineurin, according to Ca2+-CaM levels. What regulates neuronal CaM levels, is, however, unclear. CaM-binding transcription activators (CAMTAs) are ancient proteins expressed broadly in nervous systems and whose loss confers pleiotropic behavioral defects in flies, mice, and humans. Using Caenorhabditis elegans and Drosophila, we show that CAMTAs control neuronal CaM levels. The behavioral and neuronal Ca2+ signaling defects in mutants lacking camt-1, the sole C. elegans CAMTA, can be rescued by supplementing neuronal CaM. CAMT-1 binds multiple sites in the CaM promoter and deleting these sites phenocopies camt-1. Our data suggest CAMTAs mediate a conserved and general mechanism that controls neuronal CaM levels, thereby regulating Ca2+ signaling, physiology, and behavior.}, author = {Vuong-Brender, Thanh and Flynn, Sean and Vallis, Yvonne and De Bono, Mario}, issn = {2050-084X}, journal = {eLife}, publisher = {eLife Sciences Publications}, title = {{Neuronal calmodulin levels are controlled by CAMTA transcription factors}}, doi = {10.7554/eLife.68238}, volume = {10}, year = {2021}, } @article{10117, abstract = {Proximity labeling provides a powerful in vivo tool to characterize the proteome of subcellular structures and the interactome of specific proteins. The nematode Caenorhabditis elegans is one of the most intensely studied organisms in biology, offering many advantages for biochemistry. Using the highly active biotin ligase TurboID, we optimize here a proximity labeling protocol for C. elegans. An advantage of TurboID is that biotin's high affinity for streptavidin means biotin-labeled proteins can be affinity-purified under harsh denaturing conditions. By combining extensive sonication with aggressive denaturation using SDS and urea, we achieved near-complete solubilization of worm proteins. We then used this protocol to characterize the proteomes of the worm gut, muscle, skin, and nervous system. Neurons are among the smallest C. elegans cells. To probe the method's sensitivity, we expressed TurboID exclusively in the two AFD neurons and showed that the protocol could identify known and previously unknown proteins expressed selectively in AFD. The active zones of synapses are composed of a protein matrix that is difficult to solubilize and purify. To test if our protocol could solubilize active zone proteins, we knocked TurboID into the endogenous elks-1 gene, which encodes a presynaptic active zone protein. We identified many known ELKS-1-interacting active zone proteins, as well as previously uncharacterized synaptic proteins. Versatile vectors and the inherent advantages of using C. elegans, including fast growth and the ability to rapidly make and functionally test knock-ins, make proximity labeling a valuable addition to the armory of this model organism.}, author = {Artan, Murat and Barratt, Stephen and Flynn, Sean M. and Begum, Farida and Skehel, Mark and Nicolas, Armel and De Bono, Mario}, issn = {1083-351X}, journal = {Journal of Biological Chemistry}, number = {3}, publisher = {Elsevier}, title = {{Interactome analysis of Caenorhabditis elegans synapses by TurboID-based proximity labeling}}, doi = {10.1016/J.JBC.2021.101094}, volume = {297}, year = {2021}, } @article{10123, abstract = {Solution synthesis of particles emerged as an alternative to prepare thermoelectric materials with less demanding processing conditions than conventional solid-state synthetic methods. However, solution synthesis generally involves the presence of additional molecules or ions belonging to the precursors or added to enable solubility and/or regulate nucleation and growth. These molecules or ions can end up in the particles as surface adsorbates and interfere in the material properties. This work demonstrates that ionic adsorbates, in particular Na⁺ ions, are electrostatically adsorbed in SnSe particles synthesized in water and play a crucial role not only in directing the material nano/microstructure but also in determining the transport properties of the consolidated material. In dense pellets prepared by sintering SnSe particles, Na remains within the crystal lattice as dopant, in dislocations, precipitates, and forming grain boundary complexions. These results highlight the importance of considering all the possible unintentional impurities to establish proper structure-property relationships and control material properties in solution-processed thermoelectric materials.}, author = {Liu, Yu and Calcabrini, Mariano and Yu, Yuan and Genç, Aziz and Chang, Cheng and Costanzo, Tommaso and Kleinhanns, Tobias and Lee, Seungho and Llorca, Jordi and Cojocaru‐Mirédin, Oana and Ibáñez, Maria}, issn = {1521-4095}, journal = {Advanced Materials}, keywords = {mechanical engineering, mechanics of materials, general materials science}, number = {52}, publisher = {Wiley}, title = {{The importance of surface adsorbates in solution‐processed thermoelectric materials: The case of SnSe}}, doi = {10.1002/adma.202106858}, volume = {33}, year = {2021}, } @article{10124, abstract = {The transport of macromolecules and nanoscopic particles to a target cellular site is a crucial aspect in many physiological processes. This directional motion is generally controlled via active mechanical and chemical processes. Here we show, by means of molecular dynamics simulations and an analytical theory, that completely passive nanoparticles can exhibit directional motion when embedded in non-uniform mechanical environments. Specifically, we study the motion of a passive nanoparticle adhering to a mechanically non-uniform elastic membrane. We observe a non-monotonic affinity of the particle to the membrane as a function of the membrane’s rigidity, which results in the particle transport. This transport can be both up or down the rigidity gradient, depending on the absolute values of the rigidities that the gradient spans across. We conclude that rigidity gradients can be used to direct average motion of passive macromolecules and nanoparticles on deformable membranes, resulting in the preferential accumulation of the macromolecules in regions of certain mechanical properties.}, author = {Palaia, Ivan and Paraschiv, Alexandru and Debets, Vincent and Storm, Cornelis and Šarić, Anđela}, journal = {ACS Nano}, publisher = {American Chemical Society}, title = {{Durotaxis of passive nanoparticles on elastic membranes}}, doi = {10.1021/acsnano.1c02777 }, year = {2021}, } @unpublished{10125, abstract = {Living systems propagate by undergoing rounds of cell growth and division. Cell division is at heart a physical process that requires mechanical forces, usually exerted by protein assemblies. Here we developed the first physical model for the division of archaeal cells, which despite their structural simplicity share machinery and evolutionary origins with eukaryotes. We show how active geometry changes of elastic ESCRT-III filaments, coupled to filament disassembly, are sufficient to efficiently split the cell. We explore how the non-equilibrium processes that govern the filament behaviour impact the resulting cell division. We show how a quantitative comparison between our simulations and dynamic data for ESCRTIII-mediated division in Sulfolobus acidocaldarius, the closest archaeal relative to eukaryotic cells that can currently be cultured in the lab, and reveal the most likely physical mechanism behind its division.}, author = {Harker-Kirschneck, L. and Hafner, A. E. and Yao, T. and Pulschen, A. and Hurtig, F. and Vanhille-Campos, C. and Hryniuk, D. and Culley, S. and Henriques, R. and Baum, B. and Šarić, Anđela}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{Physical mechanisms of ESCRT-III-driven cell division in archaea}}, doi = {10.1101/2021.03.23.436559}, year = {2021}, } @article{10134, abstract = {We investigate the effect of coupling between translational and internal degrees of freedom of composite quantum particles on their localization in a random potential. We show that entanglement between the two degrees of freedom weakens localization due to the upper bound imposed on the inverse participation ratio by purity of a quantum state. We perform numerical calculations for a two-particle system bound by a harmonic force in a 1D disordered lattice and a rigid rotor in a 2D disordered lattice. We illustrate that the coupling has a dramatic effect on localization properties, even with a small number of internal states participating in quantum dynamics.}, author = {Suzuki, Fumika and Lemeshko, Mikhail and Zurek, Wojciech H. and Krems, Roman V.}, issn = {1079-7114}, journal = {Physical Review Letters}, keywords = {General Physics and Astronomy}, number = {16}, publisher = {American Physical Society }, title = {{Anderson localization of composite particles}}, doi = {10.1103/physrevlett.127.160602}, volume = {127}, year = {2021}, } @phdthesis{10135, abstract = {Plants maintain the capacity to develop new organs e.g. lateral roots post-embryonically throughout their whole life and thereby flexibly adapt to ever-changing environmental conditions. Plant hormones auxin and cytokinin are the main regulators of the lateral root organogenesis. Additionally to their solo activities, the interaction between auxin and cytokinin plays crucial role in fine-tuning of lateral root development and growth. In particular, cytokinin modulates auxin distribution within the developing lateral root by affecting the endomembrane trafficking of auxin transporter PIN1 and promoting its vacuolar degradation (Marhavý et al., 2011, 2014). This effect is independent of transcription and translation. Therefore, it suggests novel, non-canonical cytokinin activity occuring possibly on the posttranslational level. Impact of cytokinin and other plant hormones on auxin transporters (including PIN1) on the posttranslational level is described in detail in the introduction part of this thesis in a form of a review (Semeradova et al., 2020). To gain insights into the molecular machinery underlying cytokinin effect on the endomembrane trafficking in the plant cell, in particular on the PIN1 degradation, we conducted two large proteomic screens: 1) Identification of cytokinin binding proteins using chemical proteomics. 2) Monitoring of proteomic and phosphoproteomic changes upon cytokinin treatment. In the first screen, we identified DYNAMIN RELATED PROTEIN 2A (DRP2A). We found that DRP2A plays a role in cytokinin regulated processes during the plant growth and that cytokinin treatment promotes destabilization of DRP2A protein. However, the role of DRP2A in the PIN1 degradation remains to be elucidated. In the second screen, we found VACUOLAR PROTEIN SORTING 9A (VPS9A). VPS9a plays crucial role in plant’s response to cytokin and in cytokinin mediated PIN1 degradation. Altogether, we identified proteins, which bind to cytokinin and proteins that in response to cytokinin exhibit significantly changed abundance or phosphorylation pattern. By combining information from these two screens, we can pave our way towards understanding of noncanonical cytokinin effects.}, author = {Semerádová, Hana}, isbn = {978-3-99078-014-5}, issn = {2663-337X}, publisher = {Institute of Science and Technology Austria}, title = {{Molecular mechanisms of the cytokinin-regulated endomembrane trafficking to coordinate plant organogenesis}}, doi = {10.15479/at:ista:10135}, year = {2021}, } @article{10144, abstract = {FGFs and their high-affinity receptors (FGFRs) play key roles in development, tissue repair, and disease. Because FGFRs bind overlapping sets of ligands, their individual functions cannot be determined using ligand stimulation. Here, we generated a light-activated FGFR2 variant (OptoR2) to selectively activate signaling by the major FGFR in keratinocytes. Illumination of OptoR2-expressing HEK 293T cells activated FGFR signaling with remarkable temporal precision and promoted cell migration and proliferation. In murine and human keratinocytes, OptoR2 activation rapidly induced the classical FGFR signaling pathways and expression of FGF target genes. Surprisingly, multi-level counter-regulation occurred in keratinocytes in vitro and in transgenic mice in vivo, including OptoR2 down-regulation and loss of responsiveness to light activation. These results demonstrate unexpected cell type-specific limitations of optogenetic FGFRs in long-term in vitro and in vivo settings and highlight the complex consequences of transferring optogenetic cell signaling tools into their relevant cellular contexts.}, author = {Rauschendorfer, Theresa and Gurri, Selina and Heggli, Irina and Maddaluno, Luigi and Meyer, Michael and Inglés Prieto, Álvaro and Janovjak, Harald L and Werner, Sabine}, issn = {2575-1077}, journal = {Life Science Alliance}, number = {11}, publisher = {Life Science Alliance}, title = {{Acute and chronic effects of a light-activated FGF receptor in keratinocytes in vitro and in mice}}, doi = {10.26508/lsa.202101100}, volume = {4}, year = {2021}, } @article{10146, abstract = {The enzymes of the mitochondrial electron transport chain are key players of cell metabolism. Despite being active when isolated, in vivo they associate into supercomplexes1, whose precise role is debated. Supercomplexes CIII2CIV1-2 (refs. 2,3), CICIII2 (ref. 4) and CICIII2CIV (respirasome)5,6,7,8,9,10 exist in mammals, but in contrast to CICIII2 and the respirasome, to date the only known eukaryotic structures of CIII2CIV1-2 come from Saccharomyces cerevisiae11,12 and plants13, which have different organization. Here we present the first, to our knowledge, structures of mammalian (mouse and ovine) CIII2CIV and its assembly intermediates, in different conformations. We describe the assembly of CIII2CIV from the CIII2 precursor to the final CIII2CIV conformation, driven by the insertion of the N terminus of the assembly factor SCAF1 (ref. 14) deep into CIII2, while its C terminus is integrated into CIV. Our structures (which include CICIII2 and the respirasome) also confirm that SCAF1 is exclusively required for the assembly of CIII2CIV and has no role in the assembly of the respirasome. We show that CIII2 is asymmetric due to the presence of only one copy of subunit 9, which straddles both monomers and prevents the attachment of a second copy of SCAF1 to CIII2, explaining the presence of one copy of CIV in CIII2CIV in mammals. Finally, we show that CIII2 and CIV gain catalytic advantage when assembled into the supercomplex and propose a role for CIII2CIV in fine tuning the efficiency of electron transfer in the electron transport chain.}, author = {Vercellino, Irene and Sazanov, Leonid A}, issn = {1476-4687}, journal = {Nature}, number = {7880}, pages = {364--367}, publisher = {Springer Nature}, title = {{Structure and assembly of the mammalian mitochondrial supercomplex CIII2CIV}}, doi = {10.1038/s41586-021-03927-z}, volume = {598}, year = {2021}, } @inproceedings{10148, abstract = {Tactile feedback of an object’s surface enables us to discern its material properties and affordances. This understanding is used in digital fabrication processes by creating objects with high-resolution surface variations to influence a user’s tactile perception. As the design of such surface haptics commonly relies on knowledge from real-life experiences, it is unclear how to adapt this information for digital design methods. In this work, we investigate replicating the haptics of real materials. Using an existing process for capturing an object’s microgeometry, we digitize and reproduce the stable surface information of a set of 15 fabric samples. In a psychophysical experiment, we evaluate the tactile qualities of our set of original samples and their replicas. From our results, we see that direct reproduction of surface variations is able to influence different psychophysical dimensions of the tactile perception of surface textures. While the fabrication process did not preserve all properties, our approach underlines that replication of surface microgeometries benefits fabrication methods in terms of haptic perception by covering a large range of tactile variations. Moreover, by changing the surface structure of a single fabricated material, its material perception can be influenced. We conclude by proposing strategies for capturing and reproducing digitized textures to better resemble the perceived haptics of the originals.}, author = {Degraen, Donald and Piovarci, Michael and Bickel, Bernd and Kruger, Antonio}, booktitle = {34th Annual ACM Symposium}, isbn = {978-1-4503-8635-7}, location = {Virtual}, pages = {954--971}, publisher = {Association for Computing Machinery}, title = {{Capturing tactile properties of real surfaces for haptic reproduction}}, doi = {10.1145/3472749.3474798}, year = {2021}, } @article{10153, abstract = {Gradual typing is a principled means for mixing typed and untyped code. But typed and untyped code often exhibit different programming patterns. There is already substantial research investigating gradually giving types to code exhibiting typical untyped patterns, and some research investigating gradually removing types from code exhibiting typical typed patterns. This paper investigates how to extend these established gradual-typing concepts to give formal guarantees not only about how to change types as code evolves but also about how to change such programming patterns as well. In particular, we explore mixing untyped "structural" code with typed "nominal" code in an object-oriented language. But whereas previous work only allowed "nominal" objects to be treated as "structural" objects, we also allow "structural" objects to dynamically acquire certain nominal types, namely interfaces. We present a calculus that supports such "cross-paradigm" code migration and interoperation in a manner satisfying both the static and dynamic gradual guarantees, and demonstrate that the calculus can be implemented efficiently.}, author = {Mühlböck, Fabian and Tate, Ross}, issn = {2475-1421}, journal = {Proceedings of the ACM on Programming Languages}, keywords = {gradual typing, gradual guarantee, nominal, structural, call tags}, location = {Chicago, IL, United States}, publisher = {Association for Computing Machinery}, title = {{Transitioning from structural to nominal code with efficient gradual typing}}, doi = {10.1145/3485504}, volume = {5}, year = {2021}, } @article{10163, abstract = {The C-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) is a regulatory hub for transcription and RNA processing. Here, we identify PHD-finger protein 3 (PHF3) as a regulator of transcription and mRNA stability that docks onto Pol II CTD through its SPOC domain. We characterize SPOC as a CTD reader domain that preferentially binds two phosphorylated Serine-2 marks in adjacent CTD repeats. PHF3 drives liquid-liquid phase separation of phosphorylated Pol II, colocalizes with Pol II clusters and tracks with Pol II across the length of genes. PHF3 knock-out or SPOC deletion in human cells results in increased Pol II stalling, reduced elongation rate and an increase in mRNA stability, with marked derepression of neuronal genes. Key neuronal genes are aberrantly expressed in Phf3 knock-out mouse embryonic stem cells, resulting in impaired neuronal differentiation. Our data suggest that PHF3 acts as a prominent effector of neuronal gene regulation by bridging transcription with mRNA decay.}, author = {Appel, Lisa-Marie and Franke, Vedran and Bruno, Melania and Grishkovskaya, Irina and Kasiliauskaite, Aiste and Kaufmann, Tanja and Schoeberl, Ursula E. and Puchinger, Martin G. and Kostrhon, Sebastian and Ebenwaldner, Carmen and Sebesta, Marek and Beltzung, Etienne and Mechtler, Karl and Lin, Gen and Vlasova, Anna and Leeb, Martin and Pavri, Rushad and Stark, Alexander and Akalin, Altuna and Stefl, Richard and Bernecky, Carrie A and Djinovic-Carugo, Kristina and Slade, Dea}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {general physics and astronomy, general biochemistry, genetics and molecular biology, general chemistry}, number = {1}, publisher = {Springer Nature}, title = {{PHF3 regulates neuronal gene expression through the Pol II CTD reader domain SPOC}}, doi = {10.1038/s41467-021-26360-2}, volume = {12}, year = {2021}, } @article{10166, abstract = {While sexual reproduction is widespread among many taxa, asexual lineages have repeatedly evolved from sexual ancestors. Despite extensive research on the evolution of sex, it is still unclear whether this switch represents a major transition requiring major molecular reorganization, and how convergent the changes involved are. In this study, we investigated the phylogenetic relationship and patterns of gene expression of sexual and asexual lineages of Eurasian Artemia brine shrimp, to assess how gene expression patterns are affected by the transition to asexuality. We find only a few genes that are consistently associated with the evolution of asexuality, suggesting that this shift may not require an extensive overhauling of the meiotic machinery. While genes with sex-biased expression have high rates of expression divergence within Eurasian Artemia, neither female- nor male-biased genes appear to show unusual evolutionary patterns after sexuality is lost, contrary to theoretical expectations.}, author = {Huylmans, Ann K and Macon, Ariana and Hontoria, Francisco and Vicoso, Beatriz}, issn = {1471-2954}, journal = {Proceedings of the Royal Society B: Biological Sciences}, keywords = {asexual reproduction, parthenogenesis, sex-biased genes, sexual conflict, automixis, crustaceans}, number = {1959}, publisher = {The Royal Society}, title = {{Transitions to asexuality and evolution of gene expression in Artemia brine shrimp}}, doi = {10.1098/rspb.2021.1720}, volume = {288}, year = {2021}, } @article{10167, abstract = {Schistosomes, the human parasites responsible for snail fever, are female-heterogametic. Different parts of their ZW sex chromosomes have stopped recombining in distinct lineages, creating “evolutionary strata” of various ages. Although the Z-chromosome is well characterized at the genomic and molecular level, the W-chromosome has remained largely unstudied from an evolutionary perspective, as only a few W-linked genes have been detected outside of the model species Schistosoma mansoni. Here, we characterize the gene content and evolution of the W-chromosomes of S. mansoni and of the divergent species S. japonicum. We use a combined RNA/DNA k-mer based pipeline to assemble around 100 candidate W-specific transcripts in each of the species. About half of them map to known protein coding genes, the majority homologous to S. mansoni Z-linked genes. We perform an extended analysis of the evolutionary strata present in the two species (including characterizing a previously undetected young stratum in S. japonicum) to infer patterns of sequence and expression evolution of W-linked genes at different time points after recombination was lost. W-linked genes show evidence of degeneration, including high rates of protein evolution and reduced expression. Most are found in young lineage-specific strata, with only a few high expression ancestral W-genes remaining, consistent with the progressive erosion of nonrecombining regions. Among these, the splicing factor u2af2 stands out as a promising candidate for primary sex determination, opening new avenues for understanding the molecular basis of the reproductive biology of this group.}, author = {Elkrewi, Marwan N and Moldovan, Mikhail A. and Picard, Marion A L and Vicoso, Beatriz}, issn = {1537-1719}, journal = {Molecular Biology and Evolution}, keywords = {sex chromosomes, evolutionary strata, W-linked gene, sex determining gene, schistosome parasites}, publisher = {Oxford University Press }, title = {{Schistosome W-Linked genes inform temporal dynamics of sex chromosome evolution and suggest candidate for sex determination}}, doi = {10.1093/molbev/msab178}, year = {2021}, } @unpublished{10174, abstract = {Quantitative stochastic homogenization of linear elliptic operators is by now well-understood. In this contribution we move forward to the nonlinear setting of monotone operators with p-growth. This first work is dedicated to a quantitative two-scale expansion result. Fluctuations will be addressed in companion articles. By treating the range of exponents 2≤p<∞ in dimensions d≤3, we are able to consider genuinely nonlinear elliptic equations and systems such as −∇⋅A(x)(1+|∇u|p−2)∇u=f (with A random, non-necessarily symmetric) for the first time. When going from p=2 to p>2, the main difficulty is to analyze the associated linearized operator, whose coefficients are degenerate, unbounded, and depend on the random input A via the solution of a nonlinear equation. One of our main achievements is the control of this intricate nonlinear dependence, leading to annealed Meyers' estimates for the linearized operator, which are key to the quantitative two-scale expansion result.}, author = {Clozeau, Nicolas and Gloria, Antoine}, booktitle = {arXiv}, title = {{Quantitative nonlinear homogenization: control of oscillations}}, year = {2021}, } @article{10176, abstract = {We give a combinatorial model for r-spin surfaces with parameterized boundary based on Novak (“Lattice topological field theories in two dimensions,” Ph.D. thesis, Universität Hamburg, 2015). The r-spin structure is encoded in terms of ℤ𝑟-valued indices assigned to the edges of a polygonal decomposition. This combinatorial model is designed for our state-sum construction of two-dimensional topological field theories on r-spin surfaces. We show that an example of such a topological field theory computes the Arf-invariant of an r-spin surface as introduced by Randal-Williams [J. Topol. 7, 155 (2014)] and Geiges et al. [Osaka J. Math. 49, 449 (2012)]. This implies, in particular, that the r-spin Arf-invariant is constant on orbits of the mapping class group, providing an alternative proof of that fact.}, author = {Runkel, Ingo and Szegedy, Lorant}, issn = {00222488}, journal = {Journal of Mathematical Physics}, number = {10}, publisher = {AIP Publishing}, title = {{Topological field theory on r-spin surfaces and the Arf-invariant}}, doi = {10.1063/5.0037826}, volume = {62}, year = {2021}, } @article{10177, abstract = {Phonon polaritons (PhPs)—light coupled to lattice vibrations—with in-plane hyperbolic dispersion exhibit ray-like propagation with large wave vectors and enhanced density of optical states along certain directions on a surface. As such, they have raised a surge of interest, promising unprecedented manipulation of infrared light at the nanoscale in a planar circuitry. Here, we demonstrate focusing of in-plane hyperbolic PhPs propagating along thin slabs of α-MoO3. To that end, we developed metallic nanoantennas of convex geometries for both efficient launching and focusing of the polaritons. The foci obtained exhibit enhanced near-field confinement and absorption compared to foci produced by in-plane isotropic PhPs. Foci sizes as small as λp/4.5 = λ0/50 were achieved (λp is the polariton wavelength and λ0 is the photon wavelength). Focusing of in-plane hyperbolic polaritons introduces a first and most basic building block developing planar polariton optics using in-plane anisotropic van der Waals materials.}, author = {Martín-Sánchez, Javier and Duan, Jiahua and Taboada-Gutiérrez, Javier and Álvarez-Pérez, Gonzalo and Voronin, Kirill V. and Prieto Gonzalez, Ivan and Ma, Weiliang and Bao, Qiaoliang and Volkov, Valentyn S. and Hillenbrand, Rainer and Nikitin, Alexey Y. and Alonso-González, Pablo}, issn = {23752548}, journal = {Science Advances}, number = {41}, publisher = {American Association for the Advancement of Science}, title = {{Focusing of in-plane hyperbolic polaritons in van der Waals crystals with tailored infrared nanoantennas}}, doi = {10.1126/sciadv.abj0127}, volume = {7}, year = {2021}, } @article{10178, abstract = {In dense biological tissues, cell types performing different roles remain segregated by maintaining sharp interfaces. To better understand the mechanisms for such sharp compartmentalization, we study the effect of an imposed heterotypic tension at the interface between two distinct cell types in a fully 3D Voronoi model for confluent tissues. We find that cells rapidly sort and self-organize to generate a tissue-scale interface between cell types, and cells adjacent to this interface exhibit signature geometric features including nematic-like ordering, bimodal facet areas, and registration, or alignment, of cell centers on either side of the two-tissue interface. The magnitude of these features scales directly with the magnitude of the imposed tension, suggesting that biologists can estimate the magnitude of tissue surface tension between two tissue types simply by segmenting a 3D tissue. To uncover the underlying physical mechanisms driving these geometric features, we develop two minimal, ordered models using two different underlying lattices that identify an energetic competition between bulk cell shapes and tissue interface area. When the interface area dominates, changes to neighbor topology are costly and occur less frequently, which generates the observed geometric features.}, author = {Sahu, Preeti and Schwarz, J. M. and Manning, M. Lisa}, issn = {13672630}, journal = {New Journal of Physics}, number = {9}, publisher = {IOP Publishing}, title = {{Geometric signatures of tissue surface tension in a three-dimensional model of confluent tissue}}, doi = {10.1088/1367-2630/ac23f1}, volume = {23}, year = {2021}, } @article{10179, abstract = {Inhibitory GABAergic interneurons migrate over long distances from their extracortical origin into the developing cortex. In humans, this process is uniquely slow and prolonged, and it is unclear whether guidance cues unique to humans govern the various phases of this complex developmental process. Here, we use fused cerebral organoids to identify key roles of neurotransmitter signaling pathways in guiding the migratory behavior of human cortical interneurons. We use scRNAseq to reveal expression of GABA, glutamate, glycine, and serotonin receptors along distinct maturation trajectories across interneuron migration. We develop an image analysis software package, TrackPal, to simultaneously assess 48 parameters for entire migration tracks of individual cells. By chemical screening, we show that different modes of interneuron migration depend on distinct neurotransmitter signaling pathways, linking transcriptional maturation of interneurons with their migratory behavior. Altogether, our study provides a comprehensive quantitative analysis of human interneuron migration and its functional modulation by neurotransmitter signaling.}, author = {Bajaj, Sunanjay and Bagley, Joshua A. and Sommer, Christoph M and Vertesy, Abel and Nagumo Wong, Sakurako and Krenn, Veronica and Lévi-Strauss, Julie and Knoblich, Juergen A.}, issn = {1460-2075}, journal = {EMBO Journal}, number = {23}, publisher = {Embo Press}, title = {{Neurotransmitter signaling regulates distinct phases of multimodal human interneuron migration}}, doi = {10.15252/embj.2021108714}, volume = {40}, year = {2021}, } @article{10180, abstract = {The growing energy and performance costs of deep learning have driven the community to reduce the size of neural networks by selectively pruning components. Similarly to their biological counterparts, sparse networks generalize just as well, sometimes even better than, the original dense networks. Sparsity promises to reduce the memory footprint of regular networks to fit mobile devices, as well as shorten training time for ever growing networks. In this paper, we survey prior work on sparsity in deep learning and provide an extensive tutorial of sparsification for both inference and training. We describe approaches to remove and add elements of neural networks, different training strategies to achieve model sparsity, and mechanisms to exploit sparsity in practice. Our work distills ideas from more than 300 research papers and provides guidance to practitioners who wish to utilize sparsity today, as well as to researchers whose goal is to push the frontier forward. We include the necessary background on mathematical methods in sparsification, describe phenomena such as early structure adaptation, the intricate relations between sparsity and the training process, and show techniques for achieving acceleration on real hardware. We also define a metric of pruned parameter efficiency that could serve as a baseline for comparison of different sparse networks. We close by speculating on how sparsity can improve future workloads and outline major open problems in the field.}, author = {Hoefler, Torsten and Alistarh, Dan-Adrian and Ben-Nun, Tal and Dryden, Nikoli and Peste, Elena-Alexandra}, issn = {1533-7928}, journal = {Journal of Machine Learning Research}, number = {241}, pages = {1--124}, publisher = {Journal of Machine Learning Research}, title = {{Sparsity in deep learning: Pruning and growth for efficient inference and training in neural networks}}, volume = {22}, year = {2021}, }