TY - GEN AB - We investigate the structural similarities between liquid water and 53 ices, including 20 known crystalline phases. We base such similarity comparison on the local environments that consist of atoms within a certain cutoff radius of a central atom. We reveal that liquid water explores the local environments of the diverse ice phases, by directly comparing the environments in these phases using general atomic descriptors, and also by demonstrating that a machine-learning potential trained on liquid water alone can predict the densities, the lattice energies, and vibrational properties of the ices. The finding that the local environments characterising the different ice phases are found in water sheds light on water phase behaviors, and rationalizes the transferability of water models between different phases. AU - Monserrat, Bartomeu AU - Brandenburg, Jan Gerit AU - Engel, Edgar A. AU - Cheng, Bingqing ID - 9699 T2 - arXiv TI - Extracting ice phases from liquid water: Why a machine-learning water model generalizes so well ER - TY - JOUR AB - Desorption electrospray ionization (DESI), easy ambient sonic-spray ionization (EASI) and low-temperature plasma (LTP) ionization are powerful ambient ionization techniques for mass spectrometry. However, every single method has its limitation in terms of polarity and molecular weight of analyte molecules. After the miniaturization of every possible component of the different ion sources, we finally were able to embed two emitters and an ion transfer tubing into a small, hand-held device. The pen-like interface is connected to the mass spectrometer and a separate control unit via a bundle of flexible tubing and cables. The novel device allows the user to ionize an extended range of chemicals by simple switching between DESI, voltage-free EASI, or LTP ionization as well as to freely move the interface over a surface of interest. A mini camera, which is mounted on the tip of the pen, magnifies the desorption area and enables a simple positioning of the pen. The interface was successfully tested using different types of chemicals, pharmaceuticals, and real life samples. Moreover, the combination of optical data from the camera module and chemical data obtained by mass analysis facilitates a novel type of imaging mass spectrometry, which we name “interactive mass spectrometry imaging (IMSI)”. AU - Meisenbichler, Christina AU - Kluibenschedl, Florian AU - Müller, Thomas ID - 12940 IS - 21 JF - Analytical Chemistry KW - Analytical Chemistry SN - 0003-2700 TI - A 3-in-1 hand-held ambient mass spectrometry interface for identification and 2D localization of chemicals on surfaces VL - 92 ER - TY - JOUR AB - Linear tetrapyrroles, called phyllobilins, are obtained as major catabolites upon chlorophyll degradation. Primarily, colorless phylloleucobilins featuring four deconjugated pyrrole units were identified. Their yellow counterparts, phylloxanthobilins, were discovered more recently. Although the two catabolites differ only by one double bond, physicochemical properties are very distinct. Moreover, the presence of the double bond seems to enhance physiologically relevant bioactivities: in contrast to phylloleucobilin, we identified a potent anti-proliferative activity for a phylloxanthobilin, and show that this natural product induces apoptotic cell death and a cell cycle arrest in cancer cells. Interestingly, upon modifying inactive phylloleucobilin by esterification, an anti-proliferative activity can be observed that increases with the chain lengths of the alkyl esters. We provide first evidence for anti-cancer activity of phyllobilins, report a novel plant source for a phylloxanthobilin, and by using paper spray MS, show that these bioactive yellow chlorophyll catabolites are more prevalent in Nature than previously assumed. AU - Karg, Cornelia A. AU - Wang, Pengyu AU - Kluibenschedl, Florian AU - Müller, Thomas AU - Allmendinger, Lars AU - Vollmar, Angelika M. AU - Moser, Simone ID - 12939 IS - 29 JF - European Journal of Organic Chemistry KW - Organic Chemistry KW - Physical and Theoretical Chemistry SN - 1434-193X TI - Phylloxanthobilins are abundant linear tetrapyrroles from chlorophyll breakdown with activities against cancer cells VL - 2020 ER - TY - BOOK AB - This booklet is a collection of abstracts presented at the AHPC conference. ED - Schlögl, Alois ED - Kiss, Janos ED - Elefante, Stefano ID - 7474 SN - 978-3-99078-004-6 TI - Austrian High-Performance-Computing meeting (AHPC2020) ER - TY - CONF AB - Quantization converts neural networks into low-bit fixed-point computations which can be carried out by efficient integer-only hardware, and is standard practice for the deployment of neural networks on real-time embedded devices. However, like their real-numbered counterpart, quantized networks are not immune to malicious misclassification caused by adversarial attacks. We investigate how quantization affects a network’s robustness to adversarial attacks, which is a formal verification question. We show that neither robustness nor non-robustness are monotonic with changing the number of bits for the representation and, also, neither are preserved by quantization from a real-numbered network. For this reason, we introduce a verification method for quantized neural networks which, using SMT solving over bit-vectors, accounts for their exact, bit-precise semantics. We built a tool and analyzed the effect of quantization on a classifier for the MNIST dataset. We demonstrate that, compared to our method, existing methods for the analysis of real-numbered networks often derive false conclusions about their quantizations, both when determining robustness and when detecting attacks, and that existing methods for quantized networks often miss attacks. Furthermore, we applied our method beyond robustness, showing how the number of bits in quantization enlarges the gender bias of a predictor for students’ grades. AU - Giacobbe, Mirco AU - Henzinger, Thomas A AU - Lechner, Mathias ID - 7808 SN - 03029743 T2 - International Conference on Tools and Algorithms for the Construction and Analysis of Systems TI - How many bits does it take to quantize your neural network? VL - 12079 ER - TY - CONF AB - Isomanifolds are the generalization of isosurfaces to arbitrary dimension and codimension, i.e. manifolds defined as the zero set of some multivariate vector-valued smooth function f: ℝ^d → ℝ^(d-n). A natural (and efficient) way to approximate an isomanifold is to consider its Piecewise-Linear (PL) approximation based on a triangulation 𝒯 of the ambient space ℝ^d. In this paper, we give conditions under which the PL-approximation of an isomanifold is topologically equivalent to the isomanifold. The conditions are easy to satisfy in the sense that they can always be met by taking a sufficiently fine triangulation 𝒯. This contrasts with previous results on the triangulation of manifolds where, in arbitrary dimensions, delicate perturbations are needed to guarantee topological correctness, which leads to strong limitations in practice. We further give a bound on the Fréchet distance between the original isomanifold and its PL-approximation. Finally we show analogous results for the PL-approximation of an isomanifold with boundary. AU - Boissonnat, Jean-Daniel AU - Wintraecken, Mathijs ID - 7952 SN - 1868-8969 T2 - 36th International Symposium on Computational Geometry TI - The topological correctness of PL-approximations of isomanifolds VL - 164 ER - TY - JOUR AB - Scanning nanoscale superconducting quantum interference devices (nanoSQUIDs) are of growing interest for highly sensitive quantitative imaging of magnetic, spintronic, and transport properties of low-dimensional systems. Utilizing specifically designed grooved quartz capillaries pulled into a sharp pipette, we have fabricated the smallest SQUID-on-tip (SOT) devices with effective diameters down to 39 nm. Integration of a resistive shunt in close proximity to the pipette apex combined with self-aligned deposition of In and Sn, have resulted in SOT with a flux noise of 42 n$\Phi_0$Hz$^{-1/2}$, yielding a record low spin noise of 0.29 $\mu_B$Hz$^{-1/2}$. In addition, the new SOTs function at sub-Kelvin temperatures and in high magnetic fields of over 2.5 T. Integrating the SOTs into a scanning probe microscope allowed us to image the stray field of a single Fe$_3$O$_4$ nanocube at 300 mK. Our results show that the easy magnetization axis direction undergoes a transition from the (111) direction at room temperature to an in-plane orientation, which could be attributed to the Verwey phase transition in Fe$_3$O$_4$. AU - Anahory, Y. AU - Naren, H. R. AU - Lachman, E. O. AU - Sinai, S. Buhbut AU - Uri, A. AU - Embon, L. AU - Yaakobi, E. AU - Myasoedov, Y. AU - Huber, M. E. AU - Klajn, Rafal AU - Zeldov, E. ID - 13341 IS - 5 JF - Nanoscale TI - SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging VL - 12 ER - TY - CONF AB - Given a finite point set P in general position in the plane, a full triangulation is a maximal straight-line embedded plane graph on P. A partial triangulation on P is a full triangulation of some subset P' of P containing all extreme points in P. A bistellar flip on a partial triangulation either flips an edge, removes a non-extreme point of degree 3, or adds a point in P ⧵ P' as vertex of degree 3. The bistellar flip graph has all partial triangulations as vertices, and a pair of partial triangulations is adjacent if they can be obtained from one another by a bistellar flip. The goal of this paper is to investigate the structure of this graph, with emphasis on its connectivity. For sets P of n points in general position, we show that the bistellar flip graph is (n-3)-connected, thereby answering, for sets in general position, an open questions raised in a book (by De Loera, Rambau, and Santos) and a survey (by Lee and Santos) on triangulations. This matches the situation for the subfamily of regular triangulations (i.e., partial triangulations obtained by lifting the points and projecting the lower convex hull), where (n-3)-connectivity has been known since the late 1980s through the secondary polytope (Gelfand, Kapranov, Zelevinsky) and Balinski’s Theorem. Our methods also yield the following results (see the full version [Wagner and Welzl, 2020]): (i) The bistellar flip graph can be covered by graphs of polytopes of dimension n-3 (products of secondary polytopes). (ii) A partial triangulation is regular, if it has distance n-3 in the Hasse diagram of the partial order of partial subdivisions from the trivial subdivision. (iii) All partial triangulations are regular iff the trivial subdivision has height n-3 in the partial order of partial subdivisions. (iv) There are arbitrarily large sets P with non-regular partial triangulations, while every proper subset has only regular triangulations, i.e., there are no small certificates for the existence of non-regular partial triangulations (answering a question by F. Santos in the unexpected direction). AU - Wagner, Uli AU - Welzl, Emo ID - 7990 SN - 18688969 T2 - 36th International Symposium on Computational Geometry TI - Connectivity of triangulation flip graphs in the plane (Part II: Bistellar flips) VL - 164 ER - TY - CONF AB - In a straight-line embedded triangulation of a point set P in the plane, removing an inner edge and—provided the resulting quadrilateral is convex—adding the other diagonal is called an edge flip. The (edge) flip graph has all triangulations as vertices, and a pair of triangulations is adjacent if they can be obtained from each other by an edge flip. The goal of this paper is to contribute to a better understanding of the flip graph, with an emphasis on its connectivity. For sets in general position, it is known that every triangulation allows at least edge flips (a tight bound) which gives the minimum degree of any flip graph for n points. We show that for every point set P in general position, the flip graph is at least -vertex connected. Somewhat more strongly, we show that the vertex connectivity equals the minimum degree occurring in the flip graph, i.e. the minimum number of flippable edges in any triangulation of P, provided P is large enough. Finally, we exhibit some of the geometry of the flip graph by showing that the flip graph can be covered by 1-skeletons of polytopes of dimension (products of associahedra). A corresponding result ((n – 3)-vertex connectedness) can be shown for the bistellar flip graph of partial triangulations, i.e. the set of all triangulations of subsets of P which contain all extreme points of P. This will be treated separately in a second part. AU - Wagner, Uli AU - Welzl, Emo ID - 7807 SN - 9781611975994 T2 - Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms TI - Connectivity of triangulation flip graphs in the plane (Part I: Edge flips) VL - 2020-January ER - TY - GEN AB - The Mytilus complex of marine mussel species forms a mosaic of hybrid zones, found across temperate regions of the globe. This allows us to study "replicated" instances of secondary contact between closely-related species. Previous work on this complex has shown that local introgression is both widespread and highly heterogeneous, and has identified SNPs that are outliers of differentiation between lineages. Here, we developed an ancestry-informative panel of such SNPs. We then compared their frequencies in newly-sampled populations, including samples from within the hybrid zones, and parental populations at different distances from the contact. Results show that close to the hybrid zones, some outlier loci are near to fixation for the heterospecific allele, suggesting enhanced local introgression, or the local sweep of a shared ancestral allele. Conversely, genomic cline analyses, treating local parental populations as the reference, reveal a globally high concordance among loci, albeit with a few signals of asymmetric introgression. Enhanced local introgression at specific loci is consistent with the early transfer of adaptive variants after contact, possibly including asymmetric bi-stable variants (Dobzhansky-Muller incompatibilities), or haplotypes loaded with fewer deleterious mutations. Having escaped one barrier, however, these variants can be trapped or delayed at the next barrier, confining the introgression locally. These results shed light on the decay of species barriers during phases of contact. AU - Simon, Alexis AU - Fraisse, Christelle AU - El Ayari, Tahani AU - Liautard-Haag, Cathy AU - Strelkov, Petr AU - Welch, John AU - Bierne, Nicolas ID - 13073 TI - How do species barriers decay? concordance and local introgression in mosaic hybrid zones of mussels ER - TY - GEN AB - Domestication is a human-induced selection process that imprints the genomes of domesticated populations over a short evolutionary time scale, and that occurs in a given demographic context. Reconstructing historical gene flow, effective population size changes and their timing is therefore of fundamental interest to understand how plant demography and human selection jointly shape genomic divergence during domestication. Yet, the comparison under a single statistical framework of independent domestication histories across different crop species has been little evaluated so far. Thus, it is unclear whether domestication leads to convergent demographic changes that similarly affect crop genomes. To address this question, we used existing and new transcriptome data on three crop species of Solanaceae (eggplant, pepper and tomato), together with their close wild relatives. We fitted twelve demographic models of increasing complexity on the unfolded joint allele frequency spectrum for each wild/crop pair, and we found evidence for both shared and species-specific demographic processes between species. A convergent history of domestication with gene-flow was inferred for all three species, along with evidence of strong reduction in the effective population size during the cultivation stage of tomato and pepper. The absence of any reduction in size of the crop in eggplant stands out from the classical view of the domestication process; as does the existence of a “protracted period” of management before cultivation. Our results also suggest divergent management strategies of modern cultivars among species as their current demography substantially differs. Finally, the timing of domestication is species-specific and supported by the few historical records available. AU - Arnoux, Stephanie AU - Fraisse, Christelle AU - Sauvage, Christopher ID - 13065 TI - VCF files of synonymous SNPs related to: Genomic inference of complex domestication histories in three Solanaceae species ER - TY - JOUR AB - In nature, light is harvested by photoactive proteins to drive a range of biological processes, including photosynthesis, phototaxis, vision, and ultimately life. Bacteriorhodopsin, for example, is a protein embedded within archaeal cell membranes that binds the chromophore retinal within its hydrophobic pocket. Exposure to light triggers regioselective photoisomerization of the confined retinal, which in turn initiates a cascade of conformational changes within the protein, triggering proton flux against the concentration gradient, providing the microorganisms with the energy to live. We are inspired by these functions in nature to harness light energy using synthetic photoswitches under confinement. Like retinal, synthetic photoswitches require some degree of conformational flexibility to isomerize. In nature, the conformational change associated with retinal isomerization is accommodated by the structural flexibility of the opsin host, yet it results in steric communication between the chromophore and the protein. Similarly, we strive to design systems wherein isomerization of confined photoswitches results in steric communication between a photoswitch and its confining environment. To achieve this aim, a balance must be struck between molecular crowding and conformational freedom under confinement: too much crowding prevents switching, whereas too much freedom resembles switching of isolated molecules in solution, preventing communication. In this Account, we discuss five classes of synthetic light-switchable compounds—diarylethenes, anthracenes, azobenzenes, spiropyrans, and donor–acceptor Stenhouse adducts—comparing their behaviors under confinement and in solution. The environments employed to confine these photoswitches are diverse, ranging from planar surfaces to nanosized cavities within coordination cages, nanoporous frameworks, and nanoparticle aggregates. The trends that emerge are primarily dependent on the nature of the photoswitch and not on the material used for confinement. In general, we find that photoswitches requiring less conformational freedom for switching are, as expected, more straightforward to isomerize reversibly under confinement. Because these compounds undergo only small structural changes upon isomerization, however, switching does not propagate into communication with their environment. Conversely, photoswitches that require more conformational freedom are more challenging to switch under confinement but also can influence system-wide behavior. Although we are primarily interested in the effects of geometric constraints on photoswitching under confinement, additional effects inevitably emerge when a compound is removed from solution and placed within a new, more crowded environment. For instance, we have found that compounds that convert to zwitterionic isomers upon light irradiation often experience stabilization of these forms under confinement. This effect results from the mutual stabilization of zwitterions that are brought into close proximity on surfaces or within cavities. Furthermore, photoswitches can experience preorganization under confinement, influencing the selectivity and efficiency of their photoreactions. Because intermolecular interactions arising from confinement cannot be considered independently from the effects of geometric constraints, we describe all confinement effects concurrently throughout this Account. AU - Grommet, Angela B. AU - Lee, Lucia M. AU - Klajn, Rafal ID - 13361 IS - 11 JF - Accounts of Chemical Research KW - General Medicine KW - General Chemistry SN - 0001-4842 TI - Molecular photoswitching in confined spaces VL - 53 ER - TY - JOUR AB - Aggregation of organic molecules can drastically affect their physicochemical properties. For instance, the optical properties of BODIPY dyes are inherently related to the degree of aggregation and the mutual orientation of BODIPY units within these aggregates. Whereas the noncovalent aggregation of various BODIPY dyes has been studied in diverse media, the ill-defined nature of these aggregates has made it difficult to elucidate the structure–property relationships. Here, we studied the encapsulation of three structurally simple BODIPY derivatives within the hydrophobic cavity of a water-soluble, flexible PdII6L4 coordination cage. The cavity size allowed for the selective encapsulation of two dye molecules, irrespective of the substitution pattern on the BODIPY core. Working with a model, a pentamethyl-substituted derivative, we found that the mutual orientation of two BODIPY units in the cage’s cavity was remarkably similar to that in the crystalline state of the free dye, allowing us to isolate and characterize the smallest possible noncovalent H-type BODIPY aggregate, namely, an H-dimer. Interestingly, a CF3-substituted BODIPY, known for forming J-type aggregates, was also encapsulated as an H-dimer. Taking advantage of the dynamic nature of encapsulation, we developed a system in which reversible switching between H- and J-aggregates can be induced for multiple cycles simply by addition and subsequent destruction of the cage. We expect that the ability to rapidly and reversibly manipulate the optical properties of supramolecular inclusion complexes in aqueous media will open up avenues for developing detection systems that operate within biological environments. AU - Gemen, Julius AU - Ahrens, Johannes AU - Shimon, Linda J. W. AU - Klajn, Rafal ID - 13362 IS - 41 JF - Journal of the American Chemical Society KW - Colloid and Surface Chemistry KW - Biochemistry KW - General Chemistry KW - Catalysis SN - 0002-7863 TI - Modulating the optical properties of BODIPY dyes by noncovalent dimerization within a flexible coordination cage VL - 142 ER - TY - JOUR AB - Photochromic molecules undergo reversible isomerization upon irradiation with light at different wavelengths, a process that can alter their physical and chemical properties. For instance, dihydropyrene (DHP) is a deep-colored compound that isomerizes to light-brown cyclophanediene (CPD) upon irradiation with visible light. CPD can then isomerize back to DHP upon irradiation with UV light or thermally in the dark. Conversion between DHP and CPD is thought to proceed via a biradical intermediate; bimolecular events involving this unstable intermediate thus result in rapid decomposition and poor cycling performance. Here, we show that the reversible isomerization of DHP can be stabilized upon confinement within a PdII6L4 coordination cage. By protecting this reactive intermediate using the cage, each isomerization reaction proceeds to higher yield, which significantly decreases the fatigue experienced by the system upon repeated photocycling. Although molecular confinement is known to help stabilize reactive species, this effect is not typically employed to protect reactive intermediates and thus improve reaction yields. We envisage that performing reactions under confinement will not only improve the cyclic performance of photochromic molecules, but may also increase the amount of product obtainable from traditionally low-yielding organic reactions. AU - Canton, Martina AU - Grommet, Angela B. AU - Pesce, Luca AU - Gemen, Julius AU - Li, Shiming AU - Diskin-Posner, Yael AU - Credi, Alberto AU - Pavan, Giovanni M. AU - Andréasson, Joakim AU - Klajn, Rafal ID - 13364 IS - 34 JF - Journal of the American Chemical Society KW - Colloid and Surface Chemistry KW - Biochemistry KW - General Chemistry KW - Catalysis SN - 0002-7863 TI - Improving fatigue resistance of dihydropyrene by encapsulation within a coordination cage VL - 142 ER - TY - JOUR AB - Photoswitchable molecules are employed for many applications, from the development of active materials to the design of stimuli-responsive molecular systems and light-powered molecular machines. To fully exploit their potential, we must learn ways to control the mechanism and kinetics of their photoinduced isomerization. One possible strategy involves confinement of photoresponsive switches such as azobenzenes or spiropyrans within crowded molecular environments, which may allow control over their light-induced conversion. However, the molecular factors that influence and control the switching process under realistic conditions and within dynamic molecular regimes often remain difficult to ascertain. As a case study, here we have employed molecular models to probe the isomerization of azobenzene guests within a Pd(II)-based coordination cage host in water. Atomistic molecular dynamics and metadynamics simulations allow us to characterize the flexibility of the cage in the solvent, the (rare) guest encapsulation and release events, and the relative probability/kinetics of light-induced isomerization of azobenzene analogues in these host–guest systems. In this way, we can reconstruct the mechanism of azobenzene switching inside the cage cavity and explore key molecular factors that may control this event. We obtain a molecular-level insight on the effects of crowding and host–guest interactions on azobenzene isomerization. The detailed picture elucidated by this study may enable the rational design of photoswitchable systems whose reactivity can be controlled via host–guest interactions. AU - Pesce, Luca AU - Perego, Claudio AU - Grommet, Angela B. AU - Klajn, Rafal AU - Pavan, Giovanni M. ID - 13365 IS - 21 JF - Journal of the American Chemical Society KW - Colloid and Surface Chemistry KW - Biochemistry KW - General Chemistry KW - Catalysis SN - 0002-7863 TI - Molecular factors controlling the isomerization of Azobenzenes in the cavity of a flexible coordination cage VL - 142 ER - TY - JOUR AB - Scanning nanoscale superconducting quantum interference devices (nanoSQUIDs) are of growing interest for highly sensitive quantitative imaging of magnetic, spintronic, and transport properties of low-dimensional systems. Utilizing specifically designed grooved quartz capillaries pulled into a sharp pipette, we have fabricated the smallest SQUID-on-tip (SOT) devices with effective diameters down to 39 nm. Integration of a resistive shunt in close proximity to the pipette apex combined with self-aligned deposition of In and Sn, has resulted in SOTs with a flux noise of 42 nΦ0 Hz−1/2, yielding a record low spin noise of 0.29 μB Hz−1/2. In addition, the new SOTs function at sub-Kelvin temperatures and in high magnetic fields of over 2.5 T. Integrating the SOTs into a scanning probe microscope allowed us to image the stray field of a single Fe3O4 nanocube at 300 mK. Our results show that the easy magnetization axis direction undergoes a transition from the 〈111〉 direction at room temperature to an in-plane orientation, which could be attributed to the Verwey phase transition in Fe3O4. AU - Anahory, Y. AU - Naren, H. R. AU - Lachman, E. O. AU - Buhbut Sinai, S. AU - Uri, A. AU - Embon, L. AU - Yaakobi, E. AU - Myasoedov, Y. AU - Huber, M. E. AU - Klajn, Rafal AU - Zeldov, E. ID - 13368 IS - 5 JF - Nanoscale KW - General Materials Science SN - 2040-3364 TI - SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging VL - 12 ER - TY - JOUR AB - Temporal activation of biological processes by visible light and subsequent return to an inactive state in the absence of light is an essential characteristic of photoreceptor cells. Inspired by these phenomena, light-responsive materials are very attractive due to the high spatiotemporal control of light irradiation, with light being able to precisely orchestrate processes repeatedly over many cycles. Herein, it is reported that light-driven proton transfer triggered by a merocyanine-based photoacid can be used to modulate the permeability of pH-responsive polymersomes through cyclic, temporally controlled protonation and deprotonation of the polymersome membrane. The membranes can undergo repeated light-driven swelling–contraction cycles without losing functional effectiveness. When applied to enzyme loaded-nanoreactors, this membrane responsiveness is used for the reversible control of enzymatic reactions. This combination of the merocyanine-based photoacid and pH-switchable nanoreactors results in rapidly responding and versatile supramolecular systems successfully used to switch enzymatic reactions ON and OFF on demand. AU - Moreno, Silvia AU - Sharan, Priyanka AU - Engelke, Johanna AU - Gumz, Hannes AU - Boye, Susanne AU - Oertel, Ulrich AU - Wang, Peng AU - Banerjee, Susanta AU - Klajn, Rafal AU - Voit, Brigitte AU - Lederer, Albena AU - Appelhans, Dietmar ID - 13363 IS - 37 JF - Small KW - Biomaterials KW - Biotechnology KW - General Materials Science KW - General Chemistry SN - 1613-6810 TI - Light‐driven proton transfer for cyclic and temporal switching of enzymatic nanoreactors VL - 16 ER - TY - JOUR AB - Confining molecules can fundamentally change their chemical and physical properties. Confinement effects are considered instrumental at various stages of the origins of life, and life continues to rely on layers of compartmentalization to maintain an out-of-equilibrium state and efficiently synthesize complex biomolecules under mild conditions. As interest in synthetic confined systems grows, we are realizing that the principles governing reactivity under confinement are the same in abiological systems as they are in nature. In this Review, we categorize the ways in which nanoconfinement effects impact chemical reactivity in synthetic systems. Under nanoconfinement, chemical properties can be modulated to increase reaction rates, enhance selectivity and stabilize reactive species. Confinement effects also lead to changes in physical properties. The fluorescence of light emitters, the colours of dyes and electronic communication between electroactive species can all be tuned under confinement. Within each of these categories, we elucidate design principles and strategies that are widely applicable across a range of confined systems, specifically highlighting examples of different nanocompartments that influence reactivity in similar ways. AU - Grommet, Angela B. AU - Feller, Moran AU - Klajn, Rafal ID - 13367 JF - Nature Nanotechnology KW - Electrical and Electronic Engineering KW - Condensed Matter Physics KW - General Materials Science KW - Biomedical Engineering KW - Atomic and Molecular Physics KW - and Optics KW - Bioengineering SN - 1748-3387 TI - Chemical reactivity under nanoconfinement VL - 15 ER - TY - CONF AB - This work analyzes the latency of the simplified successive cancellation (SSC) decoding scheme for polar codes proposed by Alamdar-Yazdi and Kschischang. It is shown that, unlike conventional successive cancellation decoding, where latency is linear in the block length, the latency of SSC decoding is sublinear. More specifically, the latency of SSC decoding is O(N 1−1/µ ), where N is the block length and µ is the scaling exponent of the channel, which captures the speed of convergence of the rate to capacity. Numerical results demonstrate the tightness of the bound and show that most of the latency reduction arises from the parallel decoding of subcodes of rate 0 and 1. AU - Mondelli, Marco AU - Hashemi, Seyyed Ali AU - Cioffi, John AU - Goldsmith, Andrea ID - 8536 SN - 21578095 T2 - IEEE International Symposium on Information Theory - Proceedings TI - Simplified successive cancellation decoding of polar codes has sublinear latency VL - 2020-June ER - TY - JOUR AB - Context. A majority of massive stars are part of binary systems, a large fraction of which will inevitably interact during their lives. Binary-interaction products (BiPs), that is, stars affected by such interaction, are expected to be commonly present in stellar populations. BiPs are thus a crucial ingredient in the understanding of stellar evolution. Aims. We aim to identify and characterize a statistically significant sample of BiPs by studying clusters of 10 − 40 Myr, an age at which binary population models predict the abundance of BiPs to be highest. One example of such a cluster is NGC 330 in the Small Magellanic Cloud. Methods. Using MUSE WFM-AO observations of NGC 330, we resolved the dense cluster core for the first time and were able to extract spectra of its entire massive star population. We developed an automated spectral classification scheme based on the equivalent widths of spectral lines in the red part of the spectrum. Results. We characterize the massive star content of the core of NGC 330, which contains more than 200 B stars, 2 O stars, 6 A-type supergiants, and 11 red supergiants. We find a lower limit on the Be star fraction of 32 ± 3% in the whole sample. It increases to at least 46 ± 10% when we only consider stars brighter than V = 17 mag. We estimate an age of the cluster core between 35 and 40 Myr and a total cluster mass of 88−18+17 × 103 M⊙. Conclusions. We find that the population in the cluster core is different than the population in the outskirts: while the stellar content in the core appears to be older than the stars in the outskirts, the Be star fraction and the observed binary fraction are significantly higher. Furthermore, we detect several BiP candidates that will be subject of future studies. AU - Bodensteiner, J. AU - Sana, H. AU - Mahy, L. AU - Patrick, L. R. AU - de Koter, A. AU - de Mink, S. E. AU - Evans, C. J. AU - Götberg, Ylva Louise Linsdotter AU - Langer, N. AU - Lennon, D. J. AU - Schneider, F. R. N. AU - Tramper, F. ID - 13466 JF - Astronomy & Astrophysics KW - stars: massive / stars: emission-line / Be / binaries: spectroscopic / blue stragglers / Magellanic Clouds SN - 0004-6361 TI - The young massive SMC cluster NGC 330 seen by MUSE VL - 634 ER - TY - JOUR AB - Gravitational-wave detections are now probing the black hole (BH) mass distribution, including the predicted pair-instability mass gap. These data require robust quantitative predictions, which are challenging to obtain. The most massive BH progenitors experience episodic mass ejections on time-scales shorter than the convective turnover time-scale. This invalidates the steady-state assumption on which the classic mixing length theory relies. We compare the final BH masses computed with two different versions of the stellar evolutionary code MESA ⁠: (i) using the default implementation of Paxton et al. (2018) and (ii) solving an additional equation accounting for the time-scale for convective deceleration. In the second grid, where stronger convection develops during the pulses and carries part of the energy, we find weaker pulses. This leads to lower amounts of mass being ejected and thus higher final BH masses of up to ∼5M⊙ ⁠. The differences are much smaller for the progenitors that determine the maximum mass of BHs below the gap. This prediction is robust at MBH,max≃48M⊙ ⁠, at least within the idealized context of this study. This is an encouraging indication that current models are robust enough for comparison with the present-day gravitational-wave detections. However, the large differences between individual models emphasize the importance of improving the treatment of convection in stellar models, especially in the light of the data anticipated from the third generation of gravitational-wave detectors. AU - Renzo, M AU - Farmer, R J AU - Justham, S AU - de Mink, S E AU - Götberg, Ylva Louise Linsdotter AU - Marchant, P ID - 13465 IS - 3 JF - Monthly Notices of the Royal Astronomical Society KW - Space and Planetary Science KW - Astronomy and Astrophysics SN - 0035-8711 TI - Sensitivity of the lower edge of the pair-instability black hole mass gap to the treatment of time-dependent convection VL - 493 ER - TY - JOUR AB - Massive stars are often found in binary systems, and it has been argued that binary products boost the ionizing radiation of stellar populations. Accurate predictions for binary products are needed to understand and quantify their contribution to cosmic reionization. We investigate the contribution of stars stripped in binaries because (1) they are, arguably, the best-understood products of binary evolution, (2) we recently produced the first radiative transfer calculations for the atmospheres of these stripped stars that predict their ionizing spectra, and (3) they are very promising sources because they boost the ionizing emission of stellar populations at late times. This allows stellar feedback to clear the surroundings such that a higher fraction of their photons can escape and ionize the intergalactic medium. Combining our detailed predictions for the ionizing spectra with a simple cosmic reionization model, we estimate that stripped stars contributed tens of percent of the photons that caused cosmic reionization of hydrogen, depending on the assumed escape fractions. More importantly, stripped stars harden the ionizing emission. We estimate that the spectral index for the ionizing part of the spectrum can increase to −1 compared to ≲ − 2 for single stars. At high redshift, stripped stars and massive single stars combined dominate the He II-ionizing emission, but we expect that active galactic nuclei drive cosmic helium reionization. Further observational consequences we expect are (1) high ionization states for the intergalactic gas surrounding stellar systems, such as C IV and Si IV, and (2) additional heating of the intergalactic medium of up to a few thousand Kelvin. Quantifying these warrants the inclusion of accurate models for stripped stars and other binary products in full cosmological simulations. AU - Götberg, Ylva Louise Linsdotter AU - de Mink, S. E. AU - McQuinn, M. AU - Zapartas, E. AU - Groh, J. H. AU - Norman, C. ID - 13467 JF - Astronomy & Astrophysics KW - Space and Planetary Science KW - Astronomy and Astrophysics SN - 0004-6361 TI - Contribution from stars stripped in binaries to cosmic reionization of hydrogen and helium VL - 634 ER - TY - JOUR AB - Present and upcoming time-domain astronomy efforts, in part driven by gravitational-wave follow-up campaigns, will unveil a variety of rare explosive transients in the sky. Here, we focus on pulsational pair-instability evolution, which can result in signatures that are observable with electromagnetic and gravitational waves. We simulated grids of bare helium stars to characterize the resulting black hole (BH) masses together with the ejecta composition, velocity, and thermal state. We find that the stars do not react “elastically” to the thermonuclear ignition in the core: there is not a one-to-one correspondence between pair-instability driven ignition and mass ejections, which causes ambiguity as to what is an observable pulse. In agreement with previous studies, we find that for initial helium core masses of 37.5 M⊙ ≲ MHe, init ≲ 41 M⊙, corresponding to carbon-oxygen core masses 27.5 M⊙ ≲ MCO ≲ 30.1 M⊙, the explosions are not strong enough to affect the surface. With increasing initial helium core mass, they become progressively stronger causing first large radial expansion (41 M⊙ ≲ MHe, init ≲ 42 M⊙, corresponding to 30.1 M⊙ ≲ MCO ≲ 30.8 M⊙) and, finally, also mass ejection episodes (for MHe, init ≳ 42 M⊙, or MCO ≳ 30.8 M⊙). The lowest mass helium core to be fully disrupted in a pair-instability supernova is MHe, init ≃ 80 M⊙, corresponding to MCO ≃ 55 M⊙. Models with MHe, init ≳ 200 M⊙ (MCO ≳ 114 M⊙) reach the photodisintegration regime, resulting in BHs with masses of MBH ≳ 125 M⊙. Although this is currently considered unlikely, if BHs from these models form via (weak) explosions, the previously-ejected material might be hit by the blast wave and convert kinetic energy into observable electromagnetic radiation. We characterize the hydrogen-free circumstellar material from the pulsational pair-instability of helium cores by simply assuming that the ejecta maintain a constant velocity after ejection. We find that our models produce helium-rich ejecta with mass of 10−3 M⊙ ≲ MCSM ≲ 40 M⊙, the larger values corresponding to the more massive progenitor stars. These ejecta are typically launched at a few thousand km s−1 and reach distances of ∼1012 − 1015 cm before the core-collapse of the star. The delays between mass ejection events and the final collapse span a wide and mass-dependent range (from subhour to 104 years), and the shells ejected can also collide with each other, powering supernova impostor events before the final core-collapse. The range of properties we find suggests a possible connection with (some) type Ibn supernovae. AU - Renzo, M. AU - Farmer, R. AU - Justham, S. AU - Götberg, Ylva Louise Linsdotter AU - de Mink, S. E. AU - Zapartas, E. AU - Marchant, P. AU - Smith, N. ID - 13463 JF - Astronomy & Astrophysics KW - Space and Planetary Science KW - Astronomy and Astrophysics SN - 0004-6361 TI - Predictions for the hydrogen-free ejecta of pulsational pair-instability supernovae VL - 640 ER - TY - JOUR AB - High-resolution numerical simulations including feedback and aimed at calculating the escape fraction (fesc) of hydrogen-ionizing photons often assume stellar radiation based on single-stellar population synthesis models. However, strong evidence suggests the binary fraction of massive stars is ≳70%. Moreover, simulations so far have yielded values of fesc falling only on the lower end of the ∼10%–20% range, the amount presumed necessary to reionize the universe. Analyzing a high-resolution (4 pc) cosmological radiation-hydrodynamic simulation, we study how fesc changes when we include two different products of binary stellar evolution—stars stripped of their hydrogen envelopes and massive blue stragglers. Both produce significant amounts of ionizing photons 10–200 Myr after each starburst. We find the relative importance of these photons to be amplified with respect to escaped ionizing photons, because peaks in star formation rates (SFRs) and fesc are often out of phase by this 10–200 Myr. Additionally, low-mass, bursty galaxies emit Lyman continuum radiation primarily from binary products when SFRs are low. Observations of these galaxies by the James Webb Space Telescope could provide crucial information on the evolution of binary stars as a function of redshift. Overall, including stripped stars and massive blue stragglers increases our photon-weighted mean escape fraction ($\langle {f}_{\mathrm{esc}}\rangle $) by ∼13% and ∼10%, respectively, resulting in $\langle {f}_{\mathrm{esc}}\rangle =17 \% $. Our results emphasize that using updated stellar population synthesis models with binary stellar evolution provides a more sound physical basis for stellar reionization. AU - Secunda, Amy AU - Cen, Renyue AU - Kimm, Taysun AU - Götberg, Ylva Louise Linsdotter AU - de Mink, Selma E. ID - 13461 IS - 1 JF - The Astrophysical Journal KW - Space and Planetary Science KW - Astronomy and Astrophysics SN - 0004-637X TI - Delayed photons from binary evolution help reionize the universe VL - 901 ER - TY - JOUR AB - Massive binaries that merge as compact objects are the progenitors of gravitational-wave sources. Most of these binaries experience one or more phases of mass transfer, during which one of the stars loses all or part of its outer envelope and becomes a stripped-envelope star. The evolution of the size of these stripped stars is crucial in determining whether they experience further interactions and understanding their ultimate fate. We present new calculations of stripped-envelope stars based on binary evolution models computed with MESA. We use these to investigate their radius evolution as a function of mass and metallicity. We further discuss their pre-supernova observable characteristics and potential consequences of their evolution on the properties of supernovae from stripped stars. At high metallicity, we find that practically all of the hydrogen-rich envelope is removed, which is in agreement with earlier findings. Only progenitors with initial masses below 10 M⊙ expand to large radii (up to 100 R⊙), while more massive progenitors remain compact. At low metallicity, a substantial amount of hydrogen remains and the progenitors can, in principle, expand to giant sizes (> 400 R⊙) for all masses we consider. This implies that they can fill their Roche lobe anew. We show that the prescriptions commonly used in population synthesis models underestimate the stellar radii by up to two orders of magnitude. We expect that this has consequences for the predictions for gravitational-wave sources from double neutron star mergers, particularly with regard to their metallicity dependence. AU - Laplace, E. AU - Götberg, Ylva Louise Linsdotter AU - de Mink, S. E. AU - Justham, S. AU - Farmer, R. ID - 13464 JF - Astronomy & Astrophysics KW - Space and Planetary Science KW - Astronomy and Astrophysics SN - 0004-6361 TI - The expansion of stripped-envelope stars: Consequences for supernovae and gravitational-wave progenitors VL - 637 ER - TY - JOUR AU - Avvakumov, Sergey AU - Wagner, Uli AU - Mabillard, Isaac AU - Skopenkov, A. B. ID - 9308 IS - 6 JF - Russian Mathematical Surveys SN - 0036-0279 TI - Eliminating higher-multiplicity intersections, III. Codimension 2 VL - 75 ER - TY - JOUR AB - We study dynamical optimal transport metrics between density matricesassociated to symmetric Dirichlet forms on finite-dimensional C∗-algebras. Our settingcovers arbitrary skew-derivations and it provides a unified framework that simultaneously generalizes recently constructed transport metrics for Markov chains, Lindblad equations, and the Fermi Ornstein–Uhlenbeck semigroup. We develop a non-nommutative differential calculus that allows us to obtain non-commutative Ricci curvature bounds, logarithmic Sobolev inequalities, transport-entropy inequalities, andspectral gap estimates. AU - Carlen, Eric A. AU - Maas, Jan ID - 6358 IS - 2 JF - Journal of Statistical Physics SN - 00224715 TI - Non-commutative calculus, optimal transport and functional inequalities in dissipative quantum systems VL - 178 ER - TY - CHAP AB - We study the Gromov waist in the sense of t-neighborhoods for measures in the Euclidean space, motivated by the famous theorem of Gromov about the waist of radially symmetric Gaussian measures. In particular, it turns our possible to extend Gromov’s original result to the case of not necessarily radially symmetric Gaussian measure. We also provide examples of measures having no t-neighborhood waist property, including a rather wide class of compactly supported radially symmetric measures and their maps into the Euclidean space of dimension at least 2. We use a simpler form of Gromov’s pancake argument to produce some estimates of t-neighborhoods of (weighted) volume-critical submanifolds in the spirit of the waist theorems, including neighborhoods of algebraic manifolds in the complex projective space. In the appendix of this paper we provide for reader’s convenience a more detailed explanation of the Caffarelli theorem that we use to handle not necessarily radially symmetric Gaussian measures. AU - Akopyan, Arseniy AU - Karasev, Roman ED - Klartag, Bo'az ED - Milman, Emanuel ID - 74 SN - 00758434 T2 - Geometric Aspects of Functional Analysis TI - Gromov's waist of non-radial Gaussian measures and radial non-Gaussian measures VL - 2256 ER - TY - JOUR AB - We develop a geometric version of the circle method and use it to compute the compactly supported cohomology of the space of rational curves through a point on a smooth affine hypersurface of sufficiently low degree. AU - Browning, Timothy D AU - Sawin, Will ID - 177 IS - 3 JF - Annals of Mathematics TI - A geometric version of the circle method VL - 191 ER - TY - JOUR AB - While Hartree–Fock theory is well established as a fundamental approximation for interacting fermions, it has been unclear how to describe corrections to it due to many-body correlations. In this paper we start from the Hartree–Fock state given by plane waves and introduce collective particle–hole pair excitations. These pairs can be approximately described by a bosonic quadratic Hamiltonian. We use Bogoliubov theory to construct a trial state yielding a rigorous Gell-Mann–Brueckner–type upper bound to the ground state energy. Our result justifies the random-phase approximation in the mean-field scaling regime, for repulsive, regular interaction potentials. AU - Benedikter, Niels P AU - Nam, Phan Thành AU - Porta, Marcello AU - Schlein, Benjamin AU - Seiringer, Robert ID - 6649 JF - Communications in Mathematical Physics SN - 0010-3616 TI - Optimal upper bound for the correlation energy of a Fermi gas in the mean-field regime VL - 374 ER - TY - JOUR AB - Nearby grid cells have been observed to express a remarkable degree of long-rangeorder, which is often idealized as extending potentially to infinity. Yet their strict peri-odic firing and ensemble coherence are theoretically possible only in flat environments, much unlike the burrows which rodents usually live in. Are the symmetrical, coherent grid maps inferred in the lab relevant to chart their way in their natural habitat? We consider spheres as simple models of curved environments and waiting for the appropriate experiments to be performed, we use our adaptation model to predict what grid maps would emerge in a network with the same type of recurrent connections, which on the plane produce coherence among the units. We find that on the sphere such connections distort the maps that single grid units would express on their own, and aggregate them into clusters. When remapping to a different spherical environment, units in each cluster maintain only partial coherence, similar to what is observed in disordered materials, such as spin glasses. AU - Stella, Federico AU - Urdapilleta, Eugenio AU - Luo, Yifan AU - Treves, Alessandro ID - 6796 IS - 4 JF - Hippocampus SN - 10509631 TI - Partial coherence and frustration in self-organizing spherical grids VL - 30 ER - TY - JOUR AB - In resource allocation games, selfish players share resources that are needed in order to fulfill their objectives. The cost of using a resource depends on the load on it. In the traditional setting, the players make their choices concurrently and in one-shot. That is, a strategy for a player is a subset of the resources. We introduce and study dynamic resource allocation games. In this setting, the game proceeds in phases. In each phase each player chooses one resource. A scheduler dictates the order in which the players proceed in a phase, possibly scheduling several players to proceed concurrently. The game ends when each player has collected a set of resources that fulfills his objective. The cost for each player then depends on this set as well as on the load on the resources in it – we consider both congestion and cost-sharing games. We argue that the dynamic setting is the suitable setting for many applications in practice. We study the stability of dynamic resource allocation games, where the appropriate notion of stability is that of subgame perfect equilibrium, study the inefficiency incurred due to selfish behavior, and also study problems that are particular to the dynamic setting, like constraints on the order in which resources can be chosen or the problem of finding a scheduler that achieves stability. AU - Avni, Guy AU - Henzinger, Thomas A AU - Kupferman, Orna ID - 6761 JF - Theoretical Computer Science SN - 03043975 TI - Dynamic resource allocation games VL - 807 ER - TY - JOUR AB - We consider the monotone variational inequality problem in a Hilbert space and describe a projection-type method with inertial terms under the following properties: (a) The method generates a strongly convergent iteration sequence; (b) The method requires, at each iteration, only one projection onto the feasible set and two evaluations of the operator; (c) The method is designed for variational inequality for which the underline operator is monotone and uniformly continuous; (d) The method includes an inertial term. The latter is also shown to speed up the convergence in our numerical results. A comparison with some related methods is given and indicates that the new method is promising. AU - Shehu, Yekini AU - Li, Xiao-Huan AU - Dong, Qiao-Li ID - 6593 JF - Numerical Algorithms SN - 1017-1398 TI - An efficient projection-type method for monotone variational inequalities in Hilbert spaces VL - 84 ER - TY - JOUR AB - Super-resolution fluorescence microscopy has become an important catalyst for discovery in the life sciences. In STimulated Emission Depletion (STED) microscopy, a pattern of light drives fluorophores from a signal-emitting on-state to a non-signalling off-state. Only emitters residing in a sub-diffraction volume around an intensity minimum are allowed to fluoresce, rendering them distinguishable from the nearby, but dark fluorophores. STED routinely achieves resolution in the few tens of nanometers range in biological samples and is suitable for live imaging. Here, we review the working principle of STED and provide general guidelines for successful STED imaging. The strive for ever higher resolution comes at the cost of increased light burden. We discuss techniques to reduce light exposure and mitigate its detrimental effects on the specimen. These include specialized illumination strategies as well as protecting fluorophores from photobleaching mediated by high-intensity STED light. This opens up the prospect of volumetric imaging in living cells and tissues with diffraction-unlimited resolution in all three spatial dimensions. AU - Jahr, Wiebke AU - Velicky, Philipp AU - Danzl, Johann G ID - 6808 IS - 3 JF - Methods SN - 1046-2023 TI - Strategies to maximize performance in STimulated Emission Depletion (STED) nanoscopy of biological specimens VL - 174 ER - TY - JOUR AB - This paper presents two algorithms. The first decides the existence of a pointed homotopy between given simplicial maps 𝑓,𝑔:𝑋→𝑌, and the second computes the group [𝛴𝑋,𝑌]∗ of pointed homotopy classes of maps from a suspension; in both cases, the target Y is assumed simply connected. More generally, these algorithms work relative to 𝐴⊆𝑋. AU - Filakovský, Marek AU - Vokřínek, Lukas ID - 6563 JF - Foundations of Computational Mathematics SN - 16153375 TI - Are two given maps homotopic? An algorithmic viewpoint VL - 20 ER - TY - JOUR AB - We present a unified framework tackling two problems: class-specific 3D reconstruction from a single image, and generation of new 3D shape samples. These tasks have received considerable attention recently; however, most existing approaches rely on 3D supervision, annotation of 2D images with keypoints or poses, and/or training with multiple views of each object instance. Our framework is very general: it can be trained in similar settings to existing approaches, while also supporting weaker supervision. Importantly, it can be trained purely from 2D images, without pose annotations, and with only a single view per instance. We employ meshes as an output representation, instead of voxels used in most prior work. This allows us to reason over lighting parameters and exploit shading information during training, which previous 2D-supervised methods cannot. Thus, our method can learn to generate and reconstruct concave object classes. We evaluate our approach in various settings, showing that: (i) it learns to disentangle shape from pose and lighting; (ii) using shading in the loss improves performance compared to just silhouettes; (iii) when using a standard single white light, our model outperforms state-of-the-art 2D-supervised methods, both with and without pose supervision, thanks to exploiting shading cues; (iv) performance improves further when using multiple coloured lights, even approaching that of state-of-the-art 3D-supervised methods; (v) shapes produced by our model capture smooth surfaces and fine details better than voxel-based approaches; and (vi) our approach supports concave classes such as bathtubs and sofas, which methods based on silhouettes cannot learn. AU - Henderson, Paul M AU - Ferrari, Vittorio ID - 6952 JF - International Journal of Computer Vision SN - 0920-5691 TI - Learning single-image 3D reconstruction by generative modelling of shape, pose and shading VL - 128 ER - TY - JOUR AB - In the cerebellum, GluD2 is exclusively expressed in Purkinje cells, where it regulates synapse formation and regeneration, synaptic plasticity, and motor learning. Delayed cognitive development in humans with GluD2 gene mutations suggests extracerebellar functions of GluD2. However, extracerebellar expression of GluD2 and its relationship with that of GluD1 are poorly understood. GluD2 mRNA and protein were widely detected, with relatively high levels observed in the olfactory glomerular layer, medial prefrontal cortex, cingulate cortex, retrosplenial granular cortex, olfactory tubercle, subiculum, striatum, lateral septum, anterodorsal thalamic nucleus, and arcuate hypothalamic nucleus. These regions were also enriched for GluD1, and many individual neurons coexpressed the two GluDs. In the retrosplenial granular cortex, GluD1 and GluD2 were selectively expressed at PSD‐95‐expressing glutamatergic synapses, and their coexpression on the same synapses was shown by SDS‐digested freeze‐fracture replica labeling. Biochemically, GluD1 and GluD2 formed coimmunoprecipitable complex formation in HEK293T cells and in the cerebral cortex and hippocampus. We further estimated the relative protein amount by quantitative immunoblotting using GluA2/GluD2 and GluA2/GluD1 chimeric proteins as standards for titration of GluD1 and GluD2 antibodies. Intriguingly, the relative amount of GluD2 was almost comparable to that of GluD1 in the postsynaptic density fraction prepared from the cerebral cortex and hippocampus. In contrast, GluD2 was overwhelmingly predominant in the cerebellum. Thus, we have determined the relative extracerebellar expression of GluD1 and GluD2 at regional, neuronal, and synaptic levels. These data provide a molecular–anatomical basis for possible competitive and cooperative interactions of GluD family members at synapses in various brain regions. AU - Nakamoto, Chihiro AU - Konno, Kohtarou AU - Miyazaki, Taisuke AU - Nakatsukasa, Ena AU - Natsume, Rie AU - Abe, Manabu AU - Kawamura, Meiko AU - Fukazawa, Yugo AU - Shigemoto, Ryuichi AU - Yamasaki, Miwako AU - Sakimura, Kenji AU - Watanabe, Masahiko ID - 7148 IS - 6 JF - Journal of Comparative Neurology SN - 0021-9967 TI - Expression mapping, quantification, and complex formation of GluD1 and GluD2 glutamate receptors in adult mouse brain VL - 528 ER - TY - JOUR AB - Removal of the Bax gene from mice completely protects the somas of retinal ganglion cells (RGCs) from apoptosis following optic nerve injury. This makes BAX a promising therapeutic target to prevent neurodegeneration. In this study, Bax+/− mice were used to test the hypothesis that lowering the quantity of BAX in RGCs would delay apoptosis following optic nerve injury. RGCs were damaged by performing optic nerve crush (ONC) and then immunostaining for phospho-cJUN, and quantitative PCR were used to monitor the status of the BAX activation mechanism in the months following injury. The apoptotic susceptibility of injured cells was directly tested by virally introducing GFP-BAX into Bax−/− RGCs after injury. The competency of quiescent RGCs to reactivate their BAX activation mechanism was tested by intravitreal injection of the JNK pathway agonist, anisomycin. Twenty-four weeks after ONC, Bax+/− mice had significantly less cell loss in their RGC layer than Bax+/+ mice 3 weeks after ONC. Bax+/− and Bax+/+ RGCs exhibited similar patterns of nuclear phospho-cJUN accumulation immediately after ONC, which persisted in Bax+/− RGCs for up to 7 weeks before abating. The transcriptional activation of BAX-activating genes was similar in Bax+/− and Bax+/+ RGCs following ONC. Intriguingly, cells deactivated their BAX activation mechanism between 7 and 12 weeks after crush. Introduction of GFP-BAX into Bax−/− cells at 4 weeks after ONC showed that these cells had a nearly normal capacity to activate this protein, but this capacity was lost 8 weeks after crush. Collectively, these data suggest that 8–12 weeks after crush, damaged cells no longer displayed increased susceptibility to BAX activation relative to their naïve counterparts. In this same timeframe, retinal glial activation and the signaling of the pro-apoptotic JNK pathway also abated. Quiescent RGCs did not show a timely reactivation of their JNK pathway following intravitreal injection with anisomycin. These findings demonstrate that lowering the quantity of BAX in RGCs is neuroprotective after acute injury. Damaged RGCs enter a quiescent state months after injury and are no longer responsive to an apoptotic stimulus. Quiescent RGCs will require rejuvenation to reacquire functionality. AU - Donahue, RJ AU - Maes, Margaret E AU - Grosser, JA AU - Nickells, RW ID - 7033 IS - 2 JF - Molecular Neurobiology SN - 0893-7648 TI - BAX-depleted retinal ganglion cells survive and become quiescent following optic nerve damage VL - 57 ER - TY - JOUR AU - Zhang, Yuzhou AU - Friml, Jiří ID - 6997 IS - 3 JF - New Phytologist SN - 0028-646x TI - Auxin guides roots to avoid obstacles during gravitropic growth VL - 225 ER - TY - JOUR AB - In recent years, many genes have been associated with chromatinopathies classified as “Cornelia de Lange Syndrome‐like.” It is known that the phenotype of these patients becomes less recognizable, overlapping to features characteristic of other syndromes caused by genetic variants affecting different regulators of chromatin structure and function. Therefore, Cornelia de Lange syndrome diagnosis might be arduous due to the seldom discordance between unexpected molecular diagnosis and clinical evaluation. Here, we review the molecular features of Cornelia de Lange syndrome, supporting the hypothesis that “CdLS‐like syndromes” are part of a larger “rare disease family” sharing multiple clinical features and common disrupted molecular pathways. AU - Avagliano, Laura AU - Parenti, Ilaria AU - Grazioli, Paolo AU - Di Fede, Elisabetta AU - Parodi, Chiara AU - Mariani, Milena AU - Kaiser, Frank J. AU - Selicorni, Angelo AU - Gervasini, Cristina AU - Massa, Valentina ID - 7149 IS - 1 JF - Clinical Genetics SN - 0009-9163 TI - Chromatinopathies: A focus on Cornelia de Lange syndrome VL - 97 ER - TY - JOUR AB - We define an action of the (double of) Cohomological Hall algebra of Kontsevich and Soibelman on the cohomology of the moduli space of spiked instantons of Nekrasov. We identify this action with the one of the affine Yangian of gl(1). Based on that we derive the vertex algebra at the corner Wr1,r2,r3 of Gaiotto and Rapčák. We conjecture that our approach works for a big class of Calabi–Yau categories, including those associated with toric Calabi–Yau 3-folds. AU - Rapcak, Miroslav AU - Soibelman, Yan AU - Yang, Yaping AU - Zhao, Gufang ID - 7004 JF - Communications in Mathematical Physics SN - 0010-3616 TI - Cohomological Hall algebras, vertex algebras and instantons VL - 376 ER - TY - JOUR AB - Plant root architecture dynamically adapts to various environmental conditions, such as salt‐containing soil. The phytohormone abscisic acid (ABA) is involved among others also in these developmental adaptations, but the underlying molecular mechanism remains elusive. Here, a novel branch of the ABA signaling pathway in Arabidopsis involving PYR/PYL/RCAR (abbreviated as PYLs) receptor‐protein phosphatase 2A (PP2A) complex that acts in parallel to the canonical PYLs‐protein phosphatase 2C (PP2C) mechanism is identified. The PYLs‐PP2A signaling modulates root gravitropism and lateral root formation through regulating phytohormone auxin transport. In optimal conditions, PYLs ABA receptor interacts with the catalytic subunits of PP2A, increasing their phosphatase activity and thus counteracting PINOID (PID) kinase‐mediated phosphorylation of PIN‐FORMED (PIN) auxin transporters. By contrast, in salt and osmotic stress conditions, ABA binds to PYLs, inhibiting the PP2A activity, which leads to increased PIN phosphorylation and consequently modulated directional auxin transport leading to adapted root architecture. This work reveals an adaptive mechanism that may flexibly adjust plant root growth to withstand saline and osmotic stresses. It occurs via the cross‐talk between the stress hormone ABA and the versatile developmental regulator auxin. AU - Li, Yang AU - Wang, Yaping AU - Tan, Shutang AU - Li, Zhen AU - Yuan, Zhi AU - Glanc, Matous AU - Domjan, David AU - Wang, Kai AU - Xuan, Wei AU - Guo, Yan AU - Gong, Zhizhong AU - Friml, Jiří AU - Zhang, Jing ID - 7204 IS - 3 JF - Advanced Science TI - Root growth adaptation is mediated by PYLs ABA receptor-PP2A protein phosphatase complex VL - 7 ER - TY - JOUR AB - BACKGROUND:The introduction of image-guided methods to bypass surgery has resulted in optimized preoperative identification of the recipients and excellent patency rates. However, the recently presented methods have also been resource-consuming. In the present study, we have reported a cost-efficient planning workflow for extracranial-intracranial (EC-IC) revascularization combined with transdural indocyanine green videoangiography (tICG-VA). METHODS:We performed a retrospective review at a single tertiary referral center from 2011 to 2018. A novel software-derived workflow was applied for 25 of 92 bypass procedures during the study period. The precision and accuracy were assessed using tICG-VA identification of the cortical recipients and a comparison of the virtual and actual data. The data from a control group of 25 traditionally planned procedures were also matched. RESULTS:The intraoperative transfer time of the calculated coordinates averaged 0.8 minute (range, 0.4-1.9 minutes). The definitive recipients matched the targeted branches in 80%, and a neighboring branch was used in 16%. Our workflow led to a significant craniotomy size reduction in the study group compared with that in the control group (P = 0.005). tICG-VA was successfully applied in 19 cases. An average of 2 potential recipient arteries were identified transdurally, resulting in tailored durotomy and 3 craniotomy adjustments. Follow-up patency results were available for 49 bypass surgeries, comprising 54 grafts. The overall patency rate was 91% at a median follow-up period of 26 months. No significant difference was found in the patency rate between the study and control groups (P = 0.317). CONCLUSIONS:Our clinical results have validated the presented planning and surgical workflow and support the routine implementation of tICG-VA for recipient identification before durotomy. AU - Dodier, Philippe AU - Auzinger, Thomas AU - Mistelbauer, Gabriel AU - Wang, Wei Te AU - Ferraz-Leite, Heber AU - Gruber, Andreas AU - Marik, Wolfgang AU - Winter, Fabian AU - Fischer, Gerrit AU - Frischer, Josa M. AU - Bavinzski, Gerhard ID - 7220 IS - 2 JF - World Neurosurgery SN - 1878-8750 TI - Novel software-derived workflow in extracranial–intracranial bypass surgery validated by transdural indocyanine green videoangiography VL - 134 ER - TY - JOUR AB - The phytohormone auxin acts as an amazingly versatile coordinator of plant growth and development. With its morphogen-like properties, auxin controls sites and timing of differentiation and/or growth responses both, in quantitative and qualitative terms. Specificity in the auxin response depends largely on distinct modes of signal transmission, by which individual cells perceive and convert auxin signals into a remarkable diversity of responses. The best understood, or so-called canonical mechanism of auxin perception ultimately results in variable adjustments of the cellular transcriptome, via a short, nuclear signal transduction pathway. Additional findings that accumulated over decades implied that an additional, presumably, cell surface-based auxin perception mechanism mediates very rapid cellular responses and decisively contributes to the cell's overall hormonal response. Recent investigations into both, nuclear and cell surface auxin signalling challenged this assumed partition of roles for different auxin signalling pathways and revealed an unexpected complexity in transcriptional and non-transcriptional cellular responses mediated by auxin. AU - Gallei, Michelle C AU - Luschnig, Christian AU - Friml, Jiří ID - 7142 IS - 2 JF - Current Opinion in Plant Biology SN - 1369-5266 TI - Auxin signalling in growth: Schrödinger's cat out of the bag VL - 53 ER - TY - JOUR AB - In the living cell, we encounter a large variety of motile processes such as organelle transport and cytoskeleton remodeling. These processes are driven by motor proteins that generate force by transducing chemical free energy into mechanical work. In many cases, the molecular motors work in teams to collectively generate larger forces. Recent optical trapping experiments on small teams of cytoskeletal motors indicated that the collectively generated force increases with the size of the motor team but that this increase depends on the motor type and on whether the motors are studied in vitro or in vivo. Here, we use the theory of stochastic processes to describe the motion of N motors in a stationary optical trap and to compute the N-dependence of the collectively generated forces. We consider six distinct motor types, two kinesins, two dyneins, and two myosins. We show that the force increases always linearly with N but with a prefactor that depends on the performance of the single motor. Surprisingly, this prefactor increases for weaker motors with a lower stall force. This counter-intuitive behavior reflects the increased probability with which stronger motors detach from the filament during strain generation. Our theoretical results are in quantitative agreement with experimental data on small teams of kinesin-1 motors. AU - Ucar, Mehmet C AU - Lipowsky, Reinhard ID - 7166 IS - 1 JF - Nano Letters SN - 1530-6984 TI - Collective force generation by molecular motors is determined by strain-induced unbinding VL - 20 ER - TY - GEN AB - Data obtained from the fine-grained simulations used in Figures 2-5, data obtained from the coarse-grained numerical calculations used in Figure 6, and a sample script for the fine-grained simulation as a Jupyter notebook (ZIP) AU - Ucar, Mehmet C AU - Lipowsky, Reinhard ID - 9885 TI - MURL_Dataz ER - TY - JOUR AB - The combined resection of skull-infiltrating tumours and immediate cranioplastic reconstruction predominantly relies on freehand-moulded solutions. Techniques that enable this procedure to be performed easily in routine clinical practice would be useful. A cadaveric study was developed in which a new software tool was used to perform single-stage reconstructions with prefabricated implants after the resection of skull-infiltrating pathologies. A novel 3D visualization and interaction framework was developed to create 10 virtual craniotomies in five cadaveric specimens. Polyether ether ketone (PEEK) implants were manufactured according to the bone defects. The image-guided craniotomy was reconstructed with PEEK and compared to polymethyl methacrylate (PMMA). Navigational accuracy and surgical precision were assessed. The PEEK workflow resulted in up to 10-fold shorter reconstruction times than the standard technique. Surgical precision was reflected by the mean 1.1 ± 0.29 mm distance between the virtual and real craniotomy, with submillimetre precision in 50%. Assessment of the global offset between virtual and actual craniotomy revealed an average shift of 4.5 ± 3.6 mm. The results validated the ‘elective single-stage cranioplasty’ technique as a state-of-the-art virtual planning method and surgical workflow. This patient-tailored workflow could significantly reduce surgical times compared to the traditional, intraoperative acrylic moulding method and may be an option for the reconstruction of bone defects in the craniofacial region. AU - Dodier, Philippe AU - Winter, Fabian AU - Auzinger, Thomas AU - Mistelbauer, Gabriel AU - Frischer, Josa M. AU - Wang, Wei Te AU - Mallouhi, Ammar AU - Marik, Wolfgang AU - Wolfsberger, Stefan AU - Reissig, Lukas AU - Hammadi, Firas AU - Matula, Christian AU - Baumann, Arnulf AU - Bavinzski, Gerhard ID - 7218 IS - 8 JF - International Journal of Oral and Maxillofacial Surgery SN - 0901-5027 TI - Single-stage bone resection and cranioplastic reconstruction: Comparison of a novel software-derived PEEK workflow with the standard reconstructive method VL - 49 ER - TY - JOUR AB - Root system architecture (RSA), governed by the phytohormone auxin, endows plants with an adaptive advantage in particular environments. Using geographically representative arabidopsis (Arabidopsis thaliana) accessions as a resource for GWA mapping, Waidmann et al. and Ogura et al. recently identified two novel components involved in modulating auxin-mediated RSA and conferring plant fitness in particular habitats. AU - Xiao, Guanghui AU - Zhang, Yuzhou ID - 7219 IS - 2 JF - Trends in Plant Science SN - 13601385 TI - Adaptive growth: Shaping auxin-mediated root system architecture VL - 25 ER - TY - JOUR AB - T lymphocytes utilize amoeboid migration to navigate effectively within complex microenvironments. The precise rearrangement of the actin cytoskeleton required for cellular forward propulsion is mediated by actin regulators, including the actin‐related protein 2/3 (Arp2/3) complex, a macromolecular machine that nucleates branched actin filaments at the leading edge. The consequences of modulating Arp2/3 activity on the biophysical properties of the actomyosin cortex and downstream T cell function are incompletely understood. We report that even a moderate decrease of Arp3 levels in T cells profoundly affects actin cortex integrity. Reduction in total F‐actin content leads to reduced cortical tension and disrupted lamellipodia formation. Instead, in Arp3‐knockdown cells, the motility mode is dominated by blebbing migration characterized by transient, balloon‐like protrusions at the leading edge. Although this migration mode seems to be compatible with interstitial migration in three‐dimensional environments, diminished locomotion kinetics and impaired cytotoxicity interfere with optimal T cell function. These findings define the importance of finely tuned, Arp2/3‐dependent mechanophysical membrane integrity in cytotoxic effector T lymphocyte activities. AU - Obeidy, Peyman AU - Ju, Lining A. AU - Oehlers, Stefan H. AU - Zulkhernain, Nursafwana S. AU - Lee, Quintin AU - Galeano Niño, Jorge L. AU - Kwan, Rain Y.Q. AU - Tikoo, Shweta AU - Cavanagh, Lois L. AU - Mrass, Paulus AU - Cook, Adam J.L. AU - Jackson, Shaun P. AU - Biro, Maté AU - Roediger, Ben AU - Sixt, Michael K AU - Weninger, Wolfgang ID - 7234 IS - 2 JF - Immunology and Cell Biology SN - 08189641 TI - Partial loss of actin nucleator actin-related protein 2/3 activity triggers blebbing in primary T lymphocytes VL - 98 ER - TY - JOUR AB - The cyclin-dependent kinase inhibitor p57KIP2 is encoded by the imprinted Cdkn1c locus, exhibits maternal expression, and is essential for cerebral cortex development. How Cdkn1c regulates corticogenesis is however not clear. To this end we employ Mosaic Analysis with Double Markers (MADM) technology to genetically dissect Cdkn1c gene function in corticogenesis at single cell resolution. We find that the previously described growth-inhibitory Cdkn1c function is a non-cell-autonomous one, acting on the whole organism. In contrast we reveal a growth-promoting cell-autonomous Cdkn1c function which at the mechanistic level mediates radial glial progenitor cell and nascent projection neuron survival. Strikingly, the growth-promoting function of Cdkn1c is highly dosage sensitive but not subject to genomic imprinting. Collectively, our results suggest that the Cdkn1c locus regulates cortical development through distinct cell-autonomous and non-cell-autonomous mechanisms. More generally, our study highlights the importance to probe the relative contributions of cell intrinsic gene function and tissue-wide mechanisms to the overall phenotype. AU - Laukoter, Susanne AU - Beattie, Robert J AU - Pauler, Florian AU - Amberg, Nicole AU - Nakayama, Keiichi I. AU - Hippenmeyer, Simon ID - 7253 JF - Nature Communications SN - 2041-1723 TI - Imprinted Cdkn1c genomic locus cell-autonomously promotes cell survival in cerebral cortex development VL - 11 ER - TY - JOUR AB - Cytoskeletal filaments such as microtubules (MTs) and filamentous actin (F-actin) dynamically support cell structure and functions. In central presynaptic terminals, F-actin is expressed along the release edge and reportedly plays diverse functional roles, but whether axonal MTs extend deep into terminals and play any physiological role remains controversial. At the calyx of Held in rats of either sex, confocal and high-resolution microscopy revealed that MTs enter deep into presynaptic terminal swellings and partially colocalize with a subset of synaptic vesicles (SVs). Electrophysiological analysis demonstrated that depolymerization of MTs specifically prolonged the slow-recovery time component of EPSCs from short-term depression induced by a train of high-frequency stimulation, whereas depolymerization of F-actin specifically prolonged the fast-recovery component. In simultaneous presynaptic and postsynaptic action potential recordings, depolymerization of MTs or F-actin significantly impaired the fidelity of high-frequency neurotransmission. We conclude that MTs and F-actin differentially contribute to slow and fast SV replenishment, thereby maintaining high-frequency neurotransmission. AU - Piriya Ananda Babu, Lashmi AU - Wang, Han Ying AU - Eguchi, Kohgaku AU - Guillaud, Laurent AU - Takahashi, Tomoyuki ID - 7339 IS - 1 JF - Journal of neuroscience TI - Microtubule and actin differentially regulate synaptic vesicle cycling to maintain high-frequency neurotransmission VL - 40 ER - TY - JOUR AB - The ability to sense environmental temperature and to coordinate growth and development accordingly, is critical to the reproductive success of plants. Flowering time is regulated at the level of gene expression by a complex network of factors that integrate environmental and developmental cues. One of the main players, involved in modulating flowering time in response to changes in ambient temperature is FLOWERING LOCUS M (FLM). FLM transcripts can undergo extensive alternative splicing producing multiple variants, of which FLM-β and FLM-δ are the most representative. While FLM-β codes for the flowering repressor FLM protein, translation of FLM-δ has the opposite effect on flowering. Here we show that the cyclin-dependent kinase G2 (CDKG2), together with its cognate cyclin, CYCLYN L1 (CYCL1) affects the alternative splicing of FLM, balancing the levels of FLM-β and FLM-δ across the ambient temperature range. In the absence of the CDKG2/CYCL1 complex, FLM-β expression is reduced while FLM-δ is increased in a temperature dependent manner and these changes are associated with an early flowering phenotype in the cdkg2 mutant lines. In addition, we found that transcript variants retaining the full FLM intron 1 are sequestered in the cell nucleus. Strikingly, FLM intron 1 splicing is also regulated by CDKG2/CYCL1. Our results provide evidence that temperature and CDKs regulate the alternative splicing of FLM, contributing to flowering time definition. AU - Nibau, Candida AU - Gallemi, Marçal AU - Dadarou, Despoina AU - Doonan, John H. AU - Cavallari, Nicola ID - 7350 JF - Frontiers in Plant Science SN - 1664-462X TI - Thermo-sensitive alternative splicing of FLOWERING LOCUS M is modulated by cyclin-dependent kinase G2 VL - 10 ER - TY - JOUR AB - Neuronal responses to complex stimuli and tasks can encompass a wide range of time scales. Understanding these responses requires measures that characterize how the information on these response patterns are represented across multiple temporal resolutions. In this paper we propose a metric – which we call multiscale relevance (MSR) – to capture the dynamical variability of the activity of single neurons across different time scales. The MSR is a non-parametric, fully featureless indicator in that it uses only the time stamps of the firing activity without resorting to any a priori covariate or invoking any specific structure in the tuning curve for neural activity. When applied to neural data from the mEC and from the ADn and PoS regions of freely-behaving rodents, we found that neurons having low MSR tend to have low mutual information and low firing sparsity across the correlates that are believed to be encoded by the region of the brain where the recordings were made. In addition, neurons with high MSR contain significant information on spatial navigation and allow to decode spatial position or head direction as efficiently as those neurons whose firing activity has high mutual information with the covariate to be decoded and significantly better than the set of neurons with high local variations in their interspike intervals. Given these results, we propose that the MSR can be used as a measure to rank and select neurons for their information content without the need to appeal to any a priori covariate. AU - Cubero, Ryan J AU - Marsili, Matteo AU - Roudi, Yasser ID - 7369 JF - Journal of Computational Neuroscience KW - Time series analysis KW - Multiple time scale analysis KW - Spike train data KW - Information theory KW - Bayesian decoding SN - 0929-5313 TI - Multiscale relevance and informative encoding in neuronal spike trains VL - 48 ER - TY - JOUR AB - We present nsCouette, a highly scalable software tool to solve the Navier–Stokes equations for incompressible fluid flow between differentially heated and independently rotating, concentric cylinders. It is based on a pseudospectral spatial discretization and dynamic time-stepping. It is implemented in modern Fortran with a hybrid MPI-OpenMP parallelization scheme and thus designed to compute turbulent flows at high Reynolds and Rayleigh numbers. An additional GPU implementation (C-CUDA) for intermediate problem sizes and a version for pipe flow (nsPipe) are also provided. AU - Lopez Alonso, Jose M AU - Feldmann, Daniel AU - Rampp, Markus AU - Vela-Martín, Alberto AU - Shi, Liang AU - Avila, Marc ID - 7364 JF - SoftwareX TI - nsCouette – A high-performance code for direct numerical simulations of turbulent Taylor–Couette flow VL - 11 ER - TY - JOUR AB - In many real-world systems, information can be transmitted in two qualitatively different ways: by copying or by transformation. Copying occurs when messages are transmitted without modification, e.g. when an offspring receives an unaltered copy of a gene from its parent. Transformation occurs when messages are modified systematically during transmission, e.g. when mutational biases occur during genetic replication. Standard information-theoretic measures do not distinguish these two modes of information transfer, although they may reflect different mechanisms and have different functional consequences. Starting from a few simple axioms, we derive a decomposition of mutual information into the information transmitted by copying versus the information transmitted by transformation. We begin with a decomposition that applies when the source and destination of the channel have the same set of messages and a notion of message identity exists. We then generalize our decomposition to other kinds of channels, which can involve different source and destination sets and broader notions of similarity. In addition, we show that copy information can be interpreted as the minimal work needed by a physical copying process, which is relevant for understanding the physics of replication. We use the proposed decomposition to explore a model of amino acid substitution rates. Our results apply to any system in which the fidelity of copying, rather than simple predictability, is of critical relevance. AU - Kolchinsky, Artemy AU - Corominas-Murtra, Bernat ID - 7431 IS - 162 JF - Journal of the Royal Society Interface TI - Decomposing information into copying versus transformation VL - 17 ER - TY - JOUR AB - Recently Kloeckner described the structure of the isometry group of the quadratic Wasserstein space W_2(R^n). It turned out that the case of the real line is exceptional in the sense that there exists an exotic isometry flow. Following this line of investigation, we compute Isom(W_p(R)), the isometry group of the Wasserstein space W_p(R) for all p \in [1,\infty) \setminus {2}. We show that W_2(R) is also exceptional regarding the parameter p: W_p(R) is isometrically rigid if and only if p is not equal to 2. Regarding the underlying space, we prove that the exceptionality of p = 2 disappears if we replace R by the compact interval [0,1]. Surprisingly, in that case, W_p([0,1]) is isometrically rigid if and only if p is not equal to 1. Moreover, W_1([0,1]) admits isometries that split mass, and Isom(W_1([0,1])) cannot be embedded into Isom(W_1(R)). AU - Geher, Gyorgy Pal AU - Titkos, Tamas AU - Virosztek, Daniel ID - 7389 IS - 8 JF - Transactions of the American Mathematical Society KW - Wasserstein space KW - isometric embeddings KW - isometric rigidity KW - exotic isometry flow SN - 00029947 TI - Isometric study of Wasserstein spaces - the real line VL - 373 ER - TY - JOUR AB - Nanomaterials produced from the bottom-up assembly of nanocrystals may incorporate ∼1020–1021 cm–3 not fully coordinated surface atoms, i.e., ∼1020–1021 cm–3 potential donor or acceptor states that can strongly affect transport properties. Therefore, to exploit the full potential of nanocrystal building blocks to produce functional nanomaterials and thin films, a proper control of their surface chemistry is required. Here, we analyze how the ligand stripping procedure influences the charge and heat transport properties of sintered PbSe nanomaterials produced from the bottom-up assembly of colloidal PbSe nanocrystals. First, we show that the removal of the native organic ligands by thermal decomposition in an inert atmosphere leaves relatively large amounts of carbon at the crystal interfaces. This carbon blocks crystal growth during consolidation and at the same time hampers charge and heat transport through the final nanomaterial. Second, we demonstrate that, by stripping ligands from the nanocrystal surface before consolidation, nanomaterials with larger crystal domains, lower porosity, and higher charge carrier concentrations are obtained, thus resulting in nanomaterials with higher electrical and thermal conductivities. In addition, the ligand displacement leaves the nanocrystal surface unprotected, facilitating oxidation and chalcogen evaporation. The influence of the ligand displacement on the nanomaterial charge transport properties is rationalized here using a two-band model based on the standard Boltzmann transport equation with the relaxation time approximation. Finally, we present an application of the produced functional nanomaterials by modeling, fabricating, and testing a simple PbSe-based thermoelectric device with a ring geometry. AU - Cadavid, Doris AU - Ortega, Silvia AU - Illera, Sergio AU - Liu, Yu AU - Ibáñez, Maria AU - Shavel, Alexey AU - Zhang, Yu AU - Li, Mengyao AU - López, Antonio M. AU - Noriega, Germán AU - Durá, Oscar Juan AU - López De La Torre, M. A. AU - Prades, Joan Daniel AU - Cabot, Andreu ID - 7467 IS - 3 JF - ACS Applied Energy Materials TI - Influence of the ligand stripping on the transport properties of nanoparticle-based PbSe nanomaterials VL - 3 ER - TY - JOUR AB - The flexible development of plants is characterized by a high capacity for post-embryonic organ formation and tissue regeneration, processes, which require tightly regulated intercellular communication and coordinated tissue (re-)polarization. The phytohormone auxin, the main driver for these processes, is able to establish polarized auxin transport channels, which are characterized by the expression and polar, subcellular localization of the PIN1 auxin transport proteins. These channels are demarcating the position of future vascular strands necessary for organ formation and tissue regeneration. Major progress has been made in the last years to understand how PINs can change their polarity in different contexts and thus guide auxin flow through the plant. However, it still remains elusive how auxin mediates the establishment of auxin conducting channels and the formation of vascular tissue and which cellular processes are involved. By the means of sophisticated regeneration experiments combined with local auxin applications in Arabidopsis thaliana inflorescence stems we show that (i) PIN subcellular dynamics, (ii) PIN internalization by clathrin-mediated trafficking and (iii) an intact actin cytoskeleton required for post-endocytic trafficking are indispensable for auxin channel formation, de novo vascular formation and vascular regeneration after wounding. These observations provide novel insights into cellular mechanism of coordinated tissue polarization during auxin canalization. AU - Mazur, Ewa AU - Gallei, Michelle C AU - Adamowski, Maciek AU - Han, Huibin AU - Robert, Hélène S. AU - Friml, Jiří ID - 7465 IS - 4 JF - Plant Science SN - 01689452 TI - Clathrin-mediated trafficking and PIN trafficking are required for auxin canalization and vascular tissue formation in Arabidopsis VL - 293 ER - TY - JOUR AB - Unpaired ligands are secreted signals that act via a GP130-like receptor, domeless, to activate JAK/STAT signalling in Drosophila. Like many mammalian cytokines, unpaireds can be activated by infection and other stresses and can promote insulin resistance in target tissues. However, the importance of this effect in non-inflammatory physiology is unknown. Here, we identify a requirement for unpaired-JAK signalling as a metabolic regulator in healthy adult Drosophila muscle. Adult muscles show basal JAK-STAT signalling activity in the absence of any immune challenge. Plasmatocytes (Drosophila macrophages) are an important source of this tonic signal. Loss of the dome receptor on adult muscles significantly reduces lifespan and causes local and systemic metabolic pathology. These pathologies result from hyperactivation of AKT and consequent deregulation of metabolism. Thus, we identify a cytokine signal that must be received in muscle to control AKT activity and metabolic homeostasis. AU - Kierdorf, Katrin AU - Hersperger, Fabian AU - Sharrock, Jessica AU - Vincent, Crystal M. AU - Ustaoglu, Pinar AU - Dou, Jiawen AU - György, Attila AU - Groß, Olaf AU - Siekhaus, Daria E AU - Dionne, Marc S. ID - 7466 JF - eLife TI - Muscle function and homeostasis require cytokine inhibition of AKT activity in Drosophila VL - 9 ER - TY - JOUR AB - Temporally organized reactivation of experiences during awake immobility periods is thought to underlie cognitive processes like planning and evaluation. While replay of trajectories is well established for the hippocampus, it is unclear whether the medial prefrontal cortex (mPFC) can reactivate sequential behavioral experiences in the awake state to support task execution. We simultaneously recorded from hippocampal and mPFC principal neurons in rats performing a mPFC-dependent rule-switching task on a plus maze. We found that mPFC neuronal activity encoded relative positions between the start and goal. During awake immobility periods, the mPFC replayed temporally organized sequences of these generalized positions, resembling entire spatial trajectories. The occurrence of mPFC trajectory replay positively correlated with rule-switching performance. However, hippocampal and mPFC trajectory replay occurred independently, indicating different functions. These results demonstrate that the mPFC can replay ordered activity patterns representing generalized locations and suggest that mPFC replay might have a role in flexible behavior. AU - Käfer, Karola AU - Nardin, Michele AU - Blahna, Karel AU - Csicsvari, Jozsef L ID - 7472 IS - 1 JF - Neuron SN - 0896-6273 TI - Replay of behavioral sequences in the medial prefrontal cortex during rule switching VL - 106 ER - TY - JOUR AB - We give a Wong-Zakai type characterisation of the solutions of quasilinear heat equations driven by space-time white noise in 1 + 1 dimensions. In order to show that the renormalisation counterterms are local in the solution, a careful arrangement of a few hundred terms is required. The main tool in this computation is a general ‘integration by parts’ formula that provides a number of linear identities for the renormalisation constants. AU - Gerencser, Mate ID - 7388 IS - 3 JF - Annales de l'Institut Henri Poincaré C, Analyse non linéaire SN - 0294-1449 TI - Nondivergence form quasilinear heat equations driven by space-time white noise VL - 37 ER - TY - JOUR AB - Glutaminase (GA) catalyzes the first step in mitochondrial glutaminolysis playing a key role in cancer metabolic reprogramming. Humans express two types of GA isoforms: GLS and GLS2. GLS isozymes have been consistently related to cell proliferation, but the role of GLS2 in cancer remains poorly understood. GLS2 is repressed in many tumor cells and a better understanding of its function in tumorigenesis may further the development of new therapeutic approaches. We analyzed GLS2 expression in HCC, GBM and neuroblastoma cells, as well as in monkey COS-7 cells. We studied GLS2 expression after induction of differentiation with phorbol ester (PMA) and transduction with the full-length cDNA of GLS2. In parallel, we investigated cell cycle progression and levels of p53, p21 and c-Myc proteins. Using the baculovirus system, human GLS2 protein was overexpressed, purified and analyzed for posttranslational modifications employing a proteomics LC-MS/MS platform. We have demonstrated a dual targeting of GLS2 in human cancer cells. Immunocytochemistry and subcellular fractionation gave consistent results demonstrating nuclear and mitochondrial locations, with the latter being predominant. Nuclear targeting was confirmed in cancer cells overexpressing c-Myc- and GFP-tagged GLS2 proteins. We assessed the subnuclear location finding a widespread distribution of GLS2 in the nucleoplasm without clear overlapping with specific nuclear substructures. GLS2 expression and nuclear accrual notably increased by treatment of SH-SY5Y cells with PMA and it correlated with cell cycle arrest at G2/M, upregulation of tumor suppressor p53 and p21 protein. A similar response was obtained by overexpression of GLS2 in T98G glioma cells, including downregulation of oncogene c-Myc. Furthermore, human GLS2 was identified as being hypusinated by MS analysis, a posttranslational modification which may be relevant for its nuclear targeting and/or function. Our studies provide evidence for a tumor suppressor role of GLS2 in certain types of cancer. The data imply that GLS2 can be regarded as a highly mobile and multilocalizing protein translocated to both mitochondria and nuclei. Upregulation of GLS2 in cancer cells induced an antiproliferative response with cell cycle arrest at the G2/M phase. AU - López De La Oliva, Amada R. AU - Campos-Sandoval, José A. AU - Gómez-García, María C. AU - Cardona, Carolina AU - Martín-Rufián, Mercedes AU - Sialana, Fernando J. AU - Castilla, Laura AU - Bae, Narkhyun AU - Lobo, Carolina AU - Peñalver, Ana AU - García-Frutos, Marina AU - Carro, David AU - Enrique, Victoria AU - Paz, José C. AU - Mirmira, Raghavendra G. AU - Gutiérrez, Antonia AU - Alonso, Francisco J. AU - Segura, Juan A. AU - Matés, José M. AU - Lubec, Gert AU - Márquez, Javier ID - 7487 IS - 1 JF - Scientific reports TI - Nuclear translocation of glutaminase GLS2 in human cancer cells associates with proliferation arrest and differentiation VL - 10 ER - TY - JOUR AB - In plants, clathrin mediated endocytosis (CME) represents the major route for cargo internalisation from the cell surface. It has been assumed to operate in an evolutionary conserved manner as in yeast and animals. Here we report characterisation of ultrastructure, dynamics and mechanisms of plant CME as allowed by our advancement in electron microscopy and quantitative live imaging techniques. Arabidopsis CME appears to follow the constant curvature model and the bona fide CME population generates vesicles of a predominantly hexagonal-basket type; larger and with faster kinetics than in other models. Contrary to the existing paradigm, actin is dispensable for CME events at the plasma membrane but plays a unique role in collecting endocytic vesicles, sorting of internalised cargos and directional endosome movement that itself actively promote CME events. Internalized vesicles display a strongly delayed and sequential uncoating. These unique features highlight the independent evolution of the plant CME mechanism during the autonomous rise of multicellularity in eukaryotes. AU - Narasimhan, Madhumitha AU - Johnson, Alexander J AU - Prizak, Roshan AU - Kaufmann, Walter AU - Tan, Shutang AU - Casillas Perez, Barbara E AU - Friml, Jiří ID - 7490 JF - eLife TI - Evolutionarily unique mechanistic framework of clathrin-mediated endocytosis in plants VL - 9 ER - TY - JOUR AB - Characteristic or classic phenotype of Cornelia de Lange syndrome (CdLS) is associated with a recognisable facial pattern. However, the heterogeneity in causal genes and the presence of overlapping syndromes have made it increasingly difficult to diagnose only by clinical features. DeepGestalt technology, and its app Face2Gene, is having a growing impact on the diagnosis and management of genetic diseases by analysing the features of affected individuals. Here, we performed a phenotypic study on a cohort of 49 individuals harbouring causative variants in known CdLS genes in order to evaluate Face2Gene utility and sensitivity in the clinical diagnosis of CdLS. Based on the profile images of patients, a diagnosis of CdLS was within the top five predicted syndromes for 97.9% of our cases and even listed as first prediction for 83.7%. The age of patients did not seem to affect the prediction accuracy, whereas our results indicate a correlation between the clinical score and affected genes. Furthermore, each gene presents a different pattern recognition that may be used to develop new neural networks with the goal of separating different genetic subtypes in CdLS. Overall, we conclude that computer-assisted image analysis based on deep learning could support the clinical diagnosis of CdLS. AU - Latorre-Pellicer, Ana AU - Ascaso, Ángela AU - Trujillano, Laura AU - Gil-Salvador, Marta AU - Arnedo, Maria AU - Lucia-Campos, Cristina AU - Antoñanzas-Pérez, Rebeca AU - Marcos-Alcalde, Iñigo AU - Parenti, Ilaria AU - Bueno-Lozano, Gloria AU - Musio, Antonio AU - Puisac, Beatriz AU - Kaiser, Frank J. AU - Ramos, Feliciano J. AU - Gómez-Puertas, Paulino AU - Pié, Juan ID - 7488 IS - 3 JF - International Journal of Molecular Sciences SN - 16616596 TI - Evaluating Face2Gene as a tool to identify Cornelia de Lange syndrome by facial phenotypes VL - 21 ER - TY - CONF AB - Neural networks have demonstrated unmatched performance in a range of classification tasks. Despite numerous efforts of the research community, novelty detection remains one of the significant limitations of neural networks. The ability to identify previously unseen inputs as novel is crucial for our understanding of the decisions made by neural networks. At runtime, inputs not falling into any of the categories learned during training cannot be classified correctly by the neural network. Existing approaches treat the neural network as a black box and try to detect novel inputs based on the confidence of the output predictions. However, neural networks are not trained to reduce their confidence for novel inputs, which limits the effectiveness of these approaches. We propose a framework to monitor a neural network by observing the hidden layers. We employ a common abstraction from program analysis - boxes - to identify novel behaviors in the monitored layers, i.e., inputs that cause behaviors outside the box. For each neuron, the boxes range over the values seen in training. The framework is efficient and flexible to achieve a desired trade-off between raising false warnings and detecting novel inputs. We illustrate the performance and the robustness to variability in the unknown classes on popular image-classification benchmarks. AU - Henzinger, Thomas A AU - Lukina, Anna AU - Schilling, Christian ID - 7505 T2 - 24th European Conference on Artificial Intelligence TI - Outside the box: Abstraction-based monitoring of neural networks VL - 325 ER - TY - JOUR AB - In this paper, we introduce a novel method for deriving higher order corrections to the mean-field description of the dynamics of interacting bosons. More precisely, we consider the dynamics of N d-dimensional bosons for large N. The bosons initially form a Bose–Einstein condensate and interact with each other via a pair potential of the form (N−1)−1Ndβv(Nβ·)forβ∈[0,14d). We derive a sequence of N-body functions which approximate the true many-body dynamics in L2(RdN)-norm to arbitrary precision in powers of N−1. The approximating functions are constructed as Duhamel expansions of finite order in terms of the first quantised analogue of a Bogoliubov time evolution. AU - Bossmann, Lea AU - Pavlović, Nataša AU - Pickl, Peter AU - Soffer, Avy ID - 7508 JF - Journal of Statistical Physics SN - 0022-4715 TI - Higher order corrections to the mean-field description of the dynamics of interacting bosons VL - 178 ER - TY - JOUR AB - Cryo electron tomography with subsequent subtomogram averaging is a powerful technique to structurally analyze macromolecular complexes in their native context. Although close to atomic resolution in principle can be obtained, it is not clear how individual experimental parameters contribute to the attainable resolution. Here, we have used immature HIV-1 lattice as a benchmarking sample to optimize the attainable resolution for subtomogram averaging. We systematically tested various experimental parameters such as the order of projections, different angular increments and the use of the Volta phase plate. We find that although any of the prominently used acquisition schemes is sufficient to obtain subnanometer resolution, dose-symmetric acquisition provides considerably better outcome. We discuss our findings in order to provide guidance for data acquisition. Our data is publicly available and might be used to further develop processing routines. AU - Turoňová, Beata AU - Hagen, Wim J.H. AU - Obr, Martin AU - Mosalaganti, Shyamal AU - Beugelink, J. Wouter AU - Zimmerli, Christian E. AU - Kräusslich, Hans Georg AU - Beck, Martin ID - 7511 JF - Nature Communications TI - Benchmarking tomographic acquisition schemes for high-resolution structural biology VL - 11 ER - TY - JOUR AB - Endophytic fungi can be beneficial to plant growth. However, the molecular mechanisms underlying colonization of Acremonium spp. remain unclear. In this study, a novel endophytic Acremonium strain was isolated from the buds of Panax notoginseng and named Acremonium sp. D212. The Acremonium sp. D212 could colonize the roots of P. notoginseng, enhance the resistance of P. notoginseng to root rot disease, and promote root growth and saponin biosynthesis in P. notoginseng. Acremonium sp. D212 could secrete indole‐3‐acetic acid (IAA) and jasmonic acid (JA), and inoculation with the fungus increased the endogenous levels of IAA and JA in P. notoginseng. Colonization of the Acremonium sp. D212 in the roots of the rice line Nipponbare was dependent on the concentration of methyl jasmonate (MeJA) (2 to 15 μM) and 1‐naphthalenacetic acid (NAA) (10 to 20 μM). Moreover, the roots of the JA signalling‐defective coi1‐18 mutant were colonized by Acremonium sp. D212 to a lesser degree than those of the wild‐type Nipponbare and miR393b‐overexpressing lines, and the colonization was rescued by MeJA but not by NAA. It suggests that the cross‐talk between JA signalling and the auxin biosynthetic pathway plays a crucial role in the colonization of Acremonium sp. D212 in host plants. AU - Han, L AU - Zhou, X AU - Zhao, Y AU - Zhu, S AU - Wu, L AU - He, Y AU - Ping, X AU - Lu, X AU - Huang, W AU - Qian, J AU - Zhang, L AU - Jiang, X AU - Zhu, D AU - Luo, C AU - Li, S AU - Dong, Q AU - Fu, Q AU - Deng, K AU - Wang, X AU - Wang, L AU - Peng, S AU - Wu, J AU - Li, W AU - Friml, Jiří AU - Zhu, Y AU - He, X AU - Du, Y ID - 7497 IS - 9 JF - Journal of Integrative Plant Biology SN - 1672-9072 TI - Colonization of endophyte Acremonium sp. D212 in Panax notoginseng and rice mediated by auxin and jasmonic acid VL - 62 ER - TY - JOUR AB - In the past two decades, our understanding of the transition to turbulence in shear flows with linearly stable laminar solutions has greatly improved. Regarding the susceptibility of the laminar flow, two concepts have been particularly useful: the edge states and the minimal seeds. In this nonlinear picture of the transition, the basin boundary of turbulence is set by the edge state's stable manifold and this manifold comes closest in energy to the laminar equilibrium at the minimal seed. We begin this paper by presenting numerical experiments in which three-dimensional perturbations are too energetic to trigger turbulence in pipe flow but they do lead to turbulence when their amplitude is reduced. We show that this seemingly counterintuitive observation is in fact consistent with the fully nonlinear description of the transition mediated by the edge state. In order to understand the physical mechanisms behind this process, we measure the turbulent kinetic energy production and dissipation rates as a function of the radial coordinate. Our main observation is that the transition to turbulence relies on the energy amplification away from the wall, as opposed to the turbulence itself, whose energy is predominantly produced near the wall. This observation is further supported by the similar analyses on the minimal seeds and the edge states. Furthermore, we show that the time evolution of production-over-dissipation curves provides a clear distinction between the different initial amplification stages of the transition to turbulence from the minimal seed. AU - Budanur, Nazmi B AU - Marensi, Elena AU - Willis, Ashley P. AU - Hof, Björn ID - 7534 IS - 2 JF - Physical Review Fluids SN - 2469-990X TI - Upper edge of chaos and the energetics of transition in pipe flow VL - 5 ER - TY - JOUR AB - We consider general self-adjoint polynomials in several independent random matrices whose entries are centered and have the same variance. We show that under certain conditions the local law holds up to the optimal scale, i.e., the eigenvalue density on scales just above the eigenvalue spacing follows the global density of states which is determined by free probability theory. We prove that these conditions hold for general homogeneous polynomials of degree two and for symmetrized products of independent matrices with i.i.d. entries, thus establishing the optimal bulk local law for these classes of ensembles. In particular, we generalize a similar result of Anderson for anticommutator. For more general polynomials our conditions are effectively checkable numerically. AU - Erdös, László AU - Krüger, Torben H AU - Nemish, Yuriy ID - 7512 IS - 12 JF - Journal of Functional Analysis SN - 00221236 TI - Local laws for polynomials of Wigner matrices VL - 278 ER - TY - JOUR AB - In this paper we study the joint convexity/concavity of the trace functions Ψp,q,s(A,B)=Tr(Bq2K∗ApKBq2)s, p,q,s∈R, where A and B are positive definite matrices and K is any fixed invertible matrix. We will give full range of (p,q,s)∈R3 for Ψp,q,s to be jointly convex/concave for all K. As a consequence, we confirm a conjecture of Carlen, Frank and Lieb. In particular, we confirm a weaker conjecture of Audenaert and Datta and obtain the full range of (α,z) for α-z Rényi relative entropies to be monotone under completely positive trace preserving maps. We also give simpler proofs of many known results, including the concavity of Ψp,0,1/p for 0