@article{7656, abstract = {We propose that correlations among neurons are generically strong enough to organize neural activity patterns into a discrete set of clusters, which can each be viewed as a population codeword. Our reasoning starts with the analysis of retinal ganglion cell data using maximum entropy models, showing that the population is robustly in a frustrated, marginally sub-critical, or glassy, state. This leads to an argument that neural populations in many other brain areas might share this structure. Next, we use latent variable models to show that this glassy state possesses well-defined clusters of neural activity. Clusters have three appealing properties: (i) clusters exhibit error correction, i.e., they are reproducibly elicited by the same stimulus despite variability at the level of constituent neurons; (ii) clusters encode qualitatively different visual features than their constituent neurons; and (iii) clusters can be learned by downstream neural circuits in an unsupervised fashion. We hypothesize that these properties give rise to a “learnable” neural code which the cortical hierarchy uses to extract increasingly complex features without supervision or reinforcement.}, author = {Berry, Michael J. and Tkačik, Gašper}, issn = {16625188}, journal = {Frontiers in Computational Neuroscience}, publisher = {Frontiers}, title = {{Clustering of neural activity: A design principle for population codes}}, doi = {10.3389/fncom.2020.00020}, volume = {14}, year = {2020}, } @article{7663, abstract = {Wood, as the most abundant carbon dioxide storing bioresource, is currently driven beyond its traditional use through creative innovations and nanotechnology. For many properties the micro- and nanostructure plays a crucial role and one key challenge is control and detection of chemical and physical processes in the confined microstructure and nanopores of the wooden cell wall. In this study, correlative Raman and atomic force microscopy show high potential for tracking in situ molecular rearrangement of wood polymers during compression. More water molecules (interpreted as wider cellulose microfibril distances) and disentangling of hemicellulose chains are detected in the opened cell wall regions, whereas an increase of lignin is revealed in the compressed areas. These results support a new more “loose” cell wall model based on flexible lignin nanodomains and advance our knowledge of the molecular reorganization during deformation of wood for optimized processing and utilization.}, author = {Felhofer, Martin and Bock, Peter and Singh, Adya and Prats Mateu, Batirtze and Zirbs, Ronald and Gierlinger, Notburga}, issn = {15306992}, journal = {Nano Letters}, number = {4}, pages = {2647--2653}, publisher = {American Chemical Society}, title = {{Wood deformation leads to rearrangement of molecules at the nanoscale}}, doi = {10.1021/acs.nanolett.0c00205}, volume = {20}, year = {2020}, } @article{7664, abstract = {Metabotropic γ-aminobutyric acid (GABAB) receptors contribute to the control of network activity and information processing in hippocampal circuits by regulating neuronal excitability and synaptic transmission. The dysfunction in the dentate gyrus (DG) has been implicated in Alzheimer´s disease (AD). Given the involvement of GABAB receptors in AD, to determine their subcellular localisation and possible alteration in granule cells of the DG in a mouse model of AD at 12 months of age, we used high-resolution immunoelectron microscopic analysis. Immunohistochemistry at the light microscopic level showed that the regional and cellular expression pattern of GABAB1 was similar in an AD model mouse expressing mutated human amyloid precursor protein and presenilin1 (APP/PS1) and in age-matched wild type mice. High-resolution immunoelectron microscopy revealed a distance-dependent gradient of immunolabelling for GABAB receptors, increasing from proximal to distal dendrites in both wild type and APP/PS1 mice. However, the overall density of GABAB receptors at the neuronal surface of these postsynaptic compartments of granule cells was significantly reduced in APP/PS1 mice. Parallel to this reduction in surface receptors, we found a significant increase in GABAB1 at cytoplasmic sites. GABAB receptors were also detected at presynaptic sites in the molecular layer of the DG. We also found a decrease in plasma membrane GABAB receptors in axon terminals contacting dendritic spines of granule cells, which was more pronounced in the outer than in the inner molecular layer. Altogether, our data showing post- and presynaptic reduction in surface GABAB receptors in the DG suggest the alteration of the GABAB-mediated modulation of excitability and synaptic transmission in granule cells, which may contribute to the cognitive dysfunctions in the APP/PS1 model of AD}, author = {Martín-Belmonte, Alejandro and Aguado, Carolina and Alfaro-Ruíz, Rocío and Moreno-Martínez, Ana Esther and De La Ossa, Luis and Martínez-Hernández, José and Buisson, Alain and Shigemoto, Ryuichi and Fukazawa, Yugo and Luján, Rafael}, issn = {14220067}, journal = {International journal of molecular sciences}, number = {7}, publisher = {MDPI}, title = {{Density of GABAB receptors is reduced in granule cells of the hippocampus in a mouse model of Alzheimer's disease}}, doi = {10.3390/ijms21072459}, volume = {21}, year = {2020}, } @article{7665, abstract = {Acute brain slice preparation is a powerful experimental model for investigating the characteristics of synaptic function in the brain. Although brain tissue is usually cut at ice-cold temperature (CT) to facilitate slicing and avoid neuronal damage, exposure to CT causes molecular and architectural changes of synapses. To address these issues, we investigated ultrastructural and electrophysiological features of synapses in mouse acute cerebellar slices prepared at ice-cold and physiological temperature (PT). In the slices prepared at CT, we found significant spine loss and reconstruction, synaptic vesicle rearrangement and decrease in synaptic proteins, all of which were not detected in slices prepared at PT. Consistent with these structural findings, slices prepared at PT showed higher release probability. Furthermore, preparation at PT allows electrophysiological recording immediately after slicing resulting in higher detectability of long-term depression (LTD) after motor learning compared with that at CT. These results indicate substantial advantages of the slice preparation at PT for investigating synaptic functions in different physiological conditions.}, author = {Eguchi, Kohgaku and Velicky, Philipp and Hollergschwandtner, Elena and Itakura, Makoto and Fukazawa, Yugo and Danzl, Johann G and Shigemoto, Ryuichi}, issn = {16625102}, journal = {Frontiers in Cellular Neuroscience}, publisher = {Frontiers Media}, title = {{Advantages of acute brain slices prepared at physiological temperature in the characterization of synaptic functions}}, doi = {10.3389/fncel.2020.00063}, volume = {14}, year = {2020}, } @article{7666, abstract = {Generalizing the decomposition of a connected planar graph into a tree and a dual tree, we prove a combinatorial analog of the classic Helmholtz–Hodge decomposition of a smooth vector field. Specifically, we show that for every polyhedral complex, K, and every dimension, p, there is a partition of the set of p-cells into a maximal p-tree, a maximal p-cotree, and a collection of p-cells whose cardinality is the p-th reduced Betti number of K. Given an ordering of the p-cells, this tri-partition is unique, and it can be computed by a matrix reduction algorithm that also constructs canonical bases of cycle and boundary groups.}, author = {Edelsbrunner, Herbert and Ölsböck, Katharina}, issn = {14320444}, journal = {Discrete and Computational Geometry}, pages = {759--775}, publisher = {Springer Nature}, title = {{Tri-partitions and bases of an ordered complex}}, doi = {10.1007/s00454-020-00188-x}, volume = {64}, year = {2020}, } @article{7672, abstract = {Large overpotentials upon discharge and charge of Li-O2 cells have motivated extensive research into heterogeneous solid electrocatalysts or non-carbon electrodes with the aim to improve rate capability, round-trip efficiency and cycle life. These features are equally governed by parasitic reactions, which are now recognized to be caused by the highly reactive singlet oxygen (1O2). However, the link between the presence of electrocatalysts and 1O2 formation in metal-O2 cells is unknown. Here, we show that, compared to pristine carbon black electrodes, a representative selection of electrocatalysts or non-carbon electrodes (noble metal, transition metal compounds) may both slightly reduce or severely increase the 1O2 formation. The individual reaction steps, where the surfaces impact the 1O2 yield are deciphered, showing that 1O2 yield from superoxide disproportionation as well as the decomposition of trace H2O2 are sensitive to catalysts. Transition metal compounds in general are prone to increase 1O2.}, author = {Samojlov, Aleksej and Schuster, David and Kahr, Jürgen and Freunberger, Stefan Alexander}, journal = {Electrochimica Acta}, number = {12}, publisher = {Elsevier}, title = {{Surface and catalyst driven singlet oxygen formation in Li-O2 cells}}, doi = {10.1016/j.electacta.2020.137175}, volume = {362}, year = {2020}, } @unpublished{7673, abstract = {Combining drugs can improve the efficacy of treatments. However, predicting the effect of drug combinations is still challenging. The combined potency of drugs determines the drug interaction, which is classified as synergistic, additive, antagonistic, or suppressive. While probabilistic, non-mechanistic models exist, there is currently no biophysical model that can predict antibiotic interactions. Here, we present a physiologically relevant model of the combined action of antibiotics that inhibit protein synthesis by targeting the ribosome. This model captures the kinetics of antibiotic binding and transport, and uses bacterial growth laws to predict growth in the presence of antibiotic combinations. We find that this biophysical model can produce all drug interaction types except suppression. We show analytically that antibiotics which cannot bind to the ribosome simultaneously generally act as substitutes for one another, leading to additive drug interactions. Previously proposed null expectations for higher-order drug interactions follow as a limiting case of our model. We further extend the model to include the effects of direct physical or allosteric interactions between individual drugs on the ribosome. Notably, such direct interactions profoundly change the combined drug effect, depending on the kinetic parameters of the drugs used. The model makes additional predictions for the effects of resistance genes on drug interactions and for interactions between ribosome-targeting antibiotics and antibiotics with other targets. These findings enhance our understanding of the interplay between drug action and cell physiology and are a key step toward a general framework for predicting drug interactions.}, author = {Kavcic, Bor and Tkačik, Gašper and Bollenbach, Tobias}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{A minimal biophysical model of combined antibiotic action}}, doi = {10.1101/2020.04.18.047886}, year = {2020}, } @unpublished{7675, abstract = {In prokaryotes, thermodynamic models of gene regulation provide a highly quantitative mapping from promoter sequences to gene expression levels that is compatible with in vivo and in vitro bio-physical measurements. Such concordance has not been achieved for models of enhancer function in eukaryotes. In equilibrium models, it is difficult to reconcile the reported short transcription factor (TF) residence times on the DNA with the high specificity of regulation. In non-equilibrium models, progress is difficult due to an explosion in the number of parameters. Here, we navigate this complexity by looking for minimal non-equilibrium enhancer models that yield desired regulatory phenotypes: low TF residence time, high specificity and tunable cooperativity. We find that a single extra parameter, interpretable as the “linking rate” by which bound TFs interact with Mediator components, enables our models to escape equilibrium bounds and access optimal regulatory phenotypes, while remaining consistent with the reported phenomenology and simple enough to be inferred from upcoming experiments. We further find that high specificity in non-equilibrium models is in a tradeoff with gene expression noise, predicting bursty dynamics — an experimentally-observed hallmark of eukaryotic transcription. By drastically reducing the vast parameter space to a much smaller subspace that optimally realizes biological function prior to inference from data, our normative approach holds promise for mathematical models in systems biology.}, author = {Grah, Rok and Zoller, Benjamin and Tkačik, Gašper}, booktitle = {bioRxiv}, publisher = {Cold Spring Harbor Laboratory}, title = {{Normative models of enhancer function}}, doi = {10.1101/2020.04.08.029405}, year = {2020}, } @phdthesis{7680, abstract = {Proteins and their complex dynamic interactions regulate cellular mechanisms from sensing and transducing extracellular signals, to mediating genetic responses, and sustaining or changing cell morphology. To manipulate these protein-protein interactions (PPIs) that govern the behavior and fate of cells, synthetically constructed, genetically encoded tools provide the means to precisely target proteins of interest (POIs), and control their subcellular localization and activity in vitro and in vivo. Ideal synthetic tools react to an orthogonal cue, i.e. a trigger that does not activate any other endogenous process, thereby allowing manipulation of the POI alone. In optogenetics, naturally occurring photosensory domain from plants, algae and bacteria are re-purposed and genetically fused to POIs. Illumination with light of a specific wavelength triggers a conformational change that can mediate PPIs, such as dimerization or oligomerization. By using light as a trigger, these tools can be activated with high spatial and temporal precision, on subcellular and millisecond scales. Chemogenetic tools consist of protein domains that recognize and bind small molecules. By genetic fusion to POIs, these domains can mediate PPIs upon addition of their specific ligands, which are often synthetically designed to provide highly specific interactions and exhibit good bioavailability. Most optogenetic tools to mediate PPIs are based on well-studied photoreceptors responding to red, blue or near-UV light, leaving a striking gap in the green band of the visible light spectrum. Among both optogenetic and chemogenetic tools, there is an abundance of methods to induce PPIs, but tools to disrupt them require UV illumination, rely on covalent linkage and subsequent enzymatic cleavage or initially result in protein clustering of unknown stoichiometry. This work describes how the recently structurally and photochemically characterized green-light responsive cobalamin-binding domains (CBDs) from bacterial transcription factors were re-purposed to function as a green-light responsive optogenetic tool. In contrast to previously engineered optogenetic tools, CBDs do not induce PPI, but rather confer a PPI already upon expression, which can be rapidly disrupted by illumination. This was employed to mimic inhibition of constitutive activity of a growth factor receptor, and successfully implement for cell signalling in mammalian cells and in vivo to rescue development in zebrafish. This work further describes the development and application of a chemically induced de-dimerizer (CDD) based on a recently identified and structurally described bacterial oxyreductase. CDD forms a dimer upon expression in absence of its cofactor, the flavin derivative F420. Safety and of domain expression and ligand exposure are demonstrated in vitro and in vivo in zebrafish. The system is further applied to inhibit cell signalling output from a chimeric receptor upon F420 treatment. CBDs and CDD expand the repertoire of synthetic tools by providing novel mechanisms of mediating PPIs, and by recognizing previously not utilized cues. In the future, they can readily be combined with existing synthetic tools to functionally manipulate PPIs in vitro and in vivo.}, author = {Kainrath, Stephanie}, issn = {2663-337X}, pages = {98}, publisher = {Institute of Science and Technology Austria}, title = {{Synthetic tools for optogenetic and chemogenetic inhibition of cellular signals}}, doi = {10.15479/AT:ISTA:7680}, year = {2020}, } @article{7683, abstract = {For any free oriented Borel–Moore homology theory A, we construct an associative product on the A-theory of the stack of Higgs torsion sheaves over a projective curve C. We show that the resulting algebra AHa0C admits a natural shuffle presentation, and prove it is faithful when A is replaced with usual Borel–Moore homology groups. We also introduce moduli spaces of stable triples, heavily inspired by Nakajima quiver varieties, whose A-theory admits an AHa0C-action. These triples can be interpreted as certain sheaves on PC(ωC⊕OC). In particular, we obtain an action of AHa0C on the cohomology of Hilbert schemes of points on T∗C.}, author = {Minets, Sasha}, issn = {14209020}, journal = {Selecta Mathematica, New Series}, number = {2}, publisher = {Springer Nature}, title = {{Cohomological Hall algebras for Higgs torsion sheaves, moduli of triples and sheaves on surfaces}}, doi = {10.1007/s00029-020-00553-x}, volume = {26}, year = {2020}, } @article{7684, author = {Gridchyn, Igor and Schönenberger, Philipp and O'Neill, Joseph and Csicsvari, Jozsef L}, issn = {10974199}, journal = {Neuron}, number = {2}, pages = {291--300.e6}, publisher = {Elsevier}, title = {{Assembly-specific disruption of hippocampal replay leads to selective memory deficit}}, doi = {10.1016/j.neuron.2020.01.021}, volume = {106}, year = {2020}, } @article{7686, abstract = {The agricultural green revolution spectacularly enhanced crop yield and lodging resistance with modified DELLA-mediated gibberellin signaling. However, this was achieved at the expense of reduced nitrogen-use efficiency (NUE). Recently, Wu et al. revealed novel gibberellin signaling that provides a blueprint for improving tillering and NUE in Green Revolution varieties (GRVs). }, author = {Xue, Huidan and Zhang, Yuzhou and Xiao, Guanghui}, issn = {1360-1385}, journal = {Trends in Plant Science}, number = {6}, pages = {520--522}, publisher = {Elsevier}, title = {{Neo-gibberellin signaling: Guiding the next generation of the green revolution}}, doi = {10.1016/j.tplants.2020.04.001}, volume = {25}, year = {2020}, } @article{7687, abstract = {A working group, which was established within the Network of Repository Managers (RepManNet), has dealt with common certifications for repositories. In addition, current requirements of the research funding agencies FWF and EU were also taken into account. The Core Trust Seal was examined in more detail. For this purpose, a questionnaire was sent to those organizations that are already certified with CTS in Austria. The answers were summarized and evaluated anonymously. It is recommended to go for a repository certification. Moreover, the development of a DINI certificate in Austria is strongly suggested.}, author = {Ernst, Doris and Novotny, Gertraud and Schönher, Eva Maria}, issn = {1022-2588}, journal = {Mitteilungen der Vereinigung Österreichischer Bibliothekarinnen und Bibliothekare}, number = {1}, pages = {46--59}, publisher = {Vereinigung Osterreichischer Bibliothekarinnen und Bibliothekare}, title = {{(Core Trust) Seal your repository!}}, doi = {10.31263/voebm.v73i1.3491}, volume = {73}, year = {2020}, } @misc{7689, abstract = {These are the supplementary research data to the publication "Zero field splitting of heavy-hole states in quantum dots". All matrix files have the same format. Within each column the bias voltage is changed. Each column corresponds to either a different gate voltage or magnetic field. The voltage values are given in mV, the current values in pA. Find a specific description in the included Readme file. }, author = {Katsaros, Georgios}, publisher = {Institute of Science and Technology Austria}, title = {{Supplementary data for "Zero field splitting of heavy-hole states in quantum dots"}}, doi = {10.15479/AT:ISTA:7689}, year = {2020}, } @article{7695, abstract = {The TPLATE complex (TPC) is a key endocytic adaptor protein complex in plants. TPC in Arabidopsis (Arabidopsis thaliana) contains six evolutionarily conserved subunits and two plant-specific subunits, AtEH1/Pan1 and AtEH2/Pan1, although cytoplasmic proteins are not associated with the hexameric subcomplex in the cytoplasm. To investigate the dynamic assembly of the octameric TPC at the plasma membrane (PM), we performed state-of-the-art dual-color live cell imaging at physiological and lowered temperatures. Lowering the temperature slowed down endocytosis, thereby enhancing the temporal resolution of the differential recruitment of endocytic components. Under both normal and lowered temperature conditions, the core TPC subunit TPLATE and the AtEH/Pan1 proteins exhibited simultaneous recruitment at the PM. These results, together with co-localization analysis of different TPC subunits, allow us to conclude that TPC in plant cells is not recruited to the PM sequentially but as an octameric complex.}, author = {Wang, J and Mylle, E and Johnson, Alexander J and Besbrugge, N and De Jaeger, G and Friml, Jiří and Pleskot, R and van Damme, D}, issn = {1532-2548}, journal = {Plant Physiology}, number = {3}, pages = {986--997}, publisher = {American Society of Plant Biologists}, title = {{High temporal resolution reveals simultaneous plasma membrane recruitment of TPLATE complex subunits}}, doi = {10.1104/pp.20.00178}, volume = {183}, year = {2020}, } @article{7697, abstract = {* Morphogenesis and adaptive tropic growth in plants depend on gradients of the phytohormone auxin, mediated by the membrane‐based PIN‐FORMED (PIN) auxin transporters. PINs localize to a particular side of the plasma membrane (PM) or to the endoplasmic reticulum (ER) to directionally transport auxin and maintain intercellular and intracellular auxin homeostasis, respectively. However, the molecular cues that confer their diverse cellular localizations remain largely unknown. * In this study, we systematically swapped the domains between ER‐ and PM‐localized PIN proteins, as well as between apical and basal PM‐localized PINs from Arabidopsis thaliana , to shed light on why PIN family members with similar topological structures reside at different membrane compartments within cells. * Our results show that not only do the N‐ and C‐terminal transmembrane domains (TMDs) and central hydrophilic loop contribute to their differential subcellular localizations and cellular polarity, but that the pairwise‐matched N‐ and C‐terminal TMDs resulting from intramolecular domain–domain coevolution are also crucial for their divergent patterns of localization. * These findings illustrate the complexity of the evolutionary path of PIN proteins in acquiring their plethora of developmental functions and adaptive growth in plants.}, author = {Zhang, Yuzhou and Hartinger, Corinna and Wang, Xiaojuan and Friml, Jiří}, issn = {1469-8137}, journal = {New Phytologist}, number = {5}, pages = {1406--1416}, publisher = {Wiley}, title = {{Directional auxin fluxes in plants by intramolecular domain‐domain co‐evolution of PIN auxin transporters}}, doi = {10.1111/nph.16629}, volume = {227}, year = {2020}, } @article{7788, abstract = {Mutations in NDUFS4, which encodes an accessory subunit of mitochondrial oxidative phosphorylation (OXPHOS) complex I (CI), induce Leigh syndrome (LS). LS is a poorly understood pediatric disorder featuring brain-specific anomalies and early death. To study the LS pathomechanism, we here compared OXPHOS proteomes between various Ndufs4−/− mouse tissues. Ndufs4−/− animals displayed significantly lower CI subunit levels in brain/diaphragm relative to other tissues (liver/heart/kidney/skeletal muscle), whereas other OXPHOS subunit levels were not reduced. Absence of NDUFS4 induced near complete absence of the NDUFA12 accessory subunit, a 50% reduction in other CI subunit levels, and an increase in specific CI assembly factors. Among the latter, NDUFAF2 was most highly increased. Regarding NDUFS4, NDUFA12 and NDUFAF2, identical results were obtained in Ndufs4−/− mouse embryonic fibroblasts (MEFs) and NDUFS4-mutated LS patient cells. Ndufs4−/− MEFs contained active CI in situ but blue-native-PAGE highlighted that NDUFAF2 attached to an inactive CI subcomplex (CI-830) and inactive assemblies of higher MW. In NDUFA12-mutated LS patient cells, NDUFA12 absence did not reduce NDUFS4 levels but triggered NDUFAF2 association to active CI. BN-PAGE revealed no such association in LS patient fibroblasts with mutations in other CI subunit-encoding genes where NDUFAF2 was attached to CI-830 (NDUFS1, NDUFV1 mutation) or not detected (NDUFS7 mutation). Supported by enzymological and CI in silico structural analysis, we conclude that absence of NDUFS4 induces near complete absence of NDUFA12 but not vice versa, and that NDUFAF2 stabilizes active CI in Ndufs4−/− mice and LS patient cells, perhaps in concert with mitochondrial inner membrane lipids.}, author = {Adjobo-Hermans, Merel J.W. and De Haas, Ria and Willems, Peter H.G.M. and Wojtala, Aleksandra and Van Emst-De Vries, Sjenet E. and Wagenaars, Jori A. and Van Den Brand, Mariel and Rodenburg, Richard J. and Smeitink, Jan A.M. and Nijtmans, Leo G. and Sazanov, Leonid A and Wieckowski, Mariusz R. and Koopman, Werner J.H.}, issn = {18792650}, journal = {Biochimica et Biophysica Acta - Bioenergetics}, number = {8}, publisher = {Elsevier}, title = {{NDUFS4 deletion triggers loss of NDUFA12 in Ndufs4−/− mice and Leigh syndrome patients: A stabilizing role for NDUFAF2}}, doi = {10.1016/j.bbabio.2020.148213}, volume = {1861}, year = {2020}, } @article{7789, abstract = {During embryonic and postnatal development, organs and tissues grow steadily to achieve their final size at the end of puberty. However, little is known about the cellular dynamics that mediate postnatal growth. By combining in vivo clonal lineage tracing, proliferation kinetics, single-cell transcriptomics, andin vitro micro-pattern experiments, we resolved the cellular dynamics taking place during postnatal skin epidermis expansion. Our data revealed that harmonious growth is engineered by a single population of developmental progenitors presenting a fixed fate imbalance of self-renewing divisions with an ever-decreasing proliferation rate. Single-cell RNA sequencing revealed that epidermal developmental progenitors form a more uniform population compared with adult stem and progenitor cells. Finally, we found that the spatial pattern of cell division orientation is dictated locally by the underlying collagen fiber orientation. Our results uncover a simple design principle of organ growth where progenitors and differentiated cells expand in harmony with their surrounding tissues.}, author = {Dekoninck, Sophie and Hannezo, Edouard B and Sifrim, Alejandro and Miroshnikova, Yekaterina A. and Aragona, Mariaceleste and Malfait, Milan and Gargouri, Souhir and De Neunheuser, Charlotte and Dubois, Christine and Voet, Thierry and Wickström, Sara A. and Simons, Benjamin D. and Blanpain, Cédric}, issn = {10974172}, journal = {Cell}, number = {3}, pages = {604--620.e22}, publisher = {Elsevier}, title = {{Defining the design principles of skin epidermis postnatal growth}}, doi = {10.1016/j.cell.2020.03.015}, volume = {181}, year = {2020}, } @article{7790, abstract = {We prove a lower bound for the free energy (per unit volume) of the two-dimensional Bose gas in the thermodynamic limit. We show that the free energy at density 𝜌 and inverse temperature 𝛽 differs from the one of the noninteracting system by the correction term 𝜋𝜌𝜌𝛽𝛽 . Here, is the scattering length of the interaction potential, and 𝛽 is the inverse Berezinskii–Kosterlitz–Thouless critical temperature for superfluidity. The result is valid in the dilute limit 𝜌 and if 𝛽𝜌 .}, author = {Deuchert, Andreas and Mayer, Simon and Seiringer, Robert}, issn = {20505094}, journal = {Forum of Mathematics, Sigma}, publisher = {Cambridge University Press}, title = {{The free energy of the two-dimensional dilute Bose gas. I. Lower bound}}, doi = {10.1017/fms.2020.17}, volume = {8}, year = {2020}, } @article{7792, abstract = {Phonon polaritons—light coupled to lattice vibrations—in polar van der Waals crystals are promising candidates for controlling the flow of energy on the nanoscale due to their strong field confinement, anisotropic propagation and ultra-long lifetime in the picosecond range1,2,3,4,5. However, the lack of tunability of their narrow and material-specific spectral range—the Reststrahlen band—severely limits their technological implementation. Here, we demonstrate that intercalation of Na atoms in the van der Waals semiconductor α-V2O5 enables a broad spectral shift of Reststrahlen bands, and that the phonon polaritons excited show ultra-low losses (lifetime of 4 ± 1 ps), similar to phonon polaritons in a non-intercalated crystal (lifetime of 6 ± 1 ps). We expect our intercalation method to be applicable to other van der Waals crystals, opening the door for the use of phonon polaritons in broad spectral bands in the mid-infrared domain.}, author = {Taboada-Gutiérrez, Javier and Álvarez-Pérez, Gonzalo and Duan, Jiahua and Ma, Weiliang and Crowley, Kyle and Prieto Gonzalez, Ivan and Bylinkin, Andrei and Autore, Marta and Volkova, Halyna and Kimura, Kenta and Kimura, Tsuyoshi and Berger, M. H. and Li, Shaojuan and Bao, Qiaoliang and Gao, Xuan P.A. and Errea, Ion and Nikitin, Alexey Y. and Hillenbrand, Rainer and Martín-Sánchez, Javier and Alonso-González, Pablo}, issn = {14764660}, journal = {Nature Materials}, pages = {964–968}, publisher = {Springer Nature}, title = {{Broad spectral tuning of ultra-low-loss polaritons in a van der Waals crystal by intercalation}}, doi = {10.1038/s41563-020-0665-0}, volume = {19}, year = {2020}, }