@article{1216, abstract = {A framework fo r extracting features in 2D transient flows, based on the acceleration field to ensure Galilean invariance is proposed in this paper. The minima of the acceleration magnitude (a superset of acceleration zeros) are extracted and discriminated into vortices and saddle points, based on the spectral properties of the velocity Jacobian. The extraction of topological features is performed with purely combinatorial algorithms from discrete computational topology. The feature points are prioritized with persistence, as a physically meaningful importance measure. These feature points are tracked in time with a robust algorithm for tracking features. Thus, a space-time hierarchy of the minima is built and vortex merging events are detected. We apply the acceleration feature extraction strategy to three two-dimensional shear flows: (1) an incompressible periodic cylinder wake, (2) an incompressible planar mixing layer and (3) a weakly compressible planar jet. The vortex-like acceleration feature points are shown to be well aligned with acceleration zeros, maxima of the vorticity magnitude, minima of the pressure field and minima of λ2.}, author = {Kasten, Jens and Reininghaus, Jan and Hotz, Ingrid and Hege, Hans and Noack, Bernd and Daviller, Guillaume and Morzyński, Marek}, journal = {Archives of Mechanics}, number = {1}, pages = {55 -- 80}, publisher = {Polish Academy of Sciences Publishing House}, title = {{Acceleration feature points of unsteady shear flows}}, volume = {68}, year = {2016}, } @article{1217, abstract = {Understanding the regulation of T-cell responses during inflammation and auto-immunity is fundamental for designing efficient therapeutic strategies against immune diseases. In this regard, prostaglandin E 2 (PGE 2) is mostly considered a myeloid-derived immunosuppressive molecule. We describe for the first time that T cells secrete PGE 2 during T-cell receptor stimulation. In addition, we show that autocrine PGE 2 signaling through EP receptors is essential for optimal CD4 + T-cell activation in vitro and in vivo, and for T helper 1 (Th1) and regulatory T cell differentiation. PGE 2 was found to provide additive co-stimulatory signaling through AKT activation. Intravital multiphoton microscopy showed that triggering EP receptors in T cells is also essential for the stability of T cell-dendritic cell (DC) interactions and Th-cell accumulation in draining lymph nodes (LNs) during inflammation. We further demonstrated that blocking EP receptors in T cells during the initial phase of collagen-induced arthritis in mice resulted in a reduction of clinical arthritis. This could be attributable to defective T-cell activation, accompanied by a decline in activated and interferon-γ-producing CD4 + Th1 cells in draining LNs. In conclusion, we prove that T lymphocytes secret picomolar concentrations of PGE 2, which in turn provide additive co-stimulatory signaling, enabling T cells to attain a favorable activation threshold. PGE 2 signaling in T cells is also required for maintaining long and stable interactions with DCs within LNs. Blockade of EP receptors in vivo impairs T-cell activation and development of T cell-mediated inflammatory responses. This may have implications in various pathophysiological settings.}, author = {Sreeramkumar, Vinatha and Hons, Miroslav and Punzón, Carmen and Stein, Jens and Sancho, David and Fresno Forcelledo, Manuel and Cuesta, Natalia}, journal = {Immunology and Cell Biology}, number = {1}, pages = {39 -- 51}, publisher = {Nature Publishing Group}, title = {{Efficient T-cell priming and activation requires signaling through prostaglandin E2 (EP) receptors}}, doi = {10.1038/icb.2015.62}, volume = {94}, year = {2016}, } @article{1218, abstract = {Investigating the physiology of cyanobacteria cultured under a diel light regime is relevant for a better understanding of the resulting growth characteristics and for specific biotechnological applications that are foreseen for these photosynthetic organisms. Here, we present the results of a multiomics study of the model cyanobacterium Synechocystis sp. strain PCC 6803, cultured in a lab-scale photobioreactor in physiological conditions relevant for large-scale culturing. The culture was sparged withN2 andCO2, leading to an anoxic environment during the dark period. Growth followed the availability of light. Metabolite analysis performed with 1Hnuclear magnetic resonance analysis showed that amino acids involved in nitrogen and sulfur assimilation showed elevated levels in the light. Most protein levels, analyzed through mass spectrometry, remained rather stable. However, several high-light-response proteins and stress-response proteins showed distinct changes at the onset of the light period. Microarray-based transcript analysis found common patterns of~56% of the transcriptome following the diel regime. These oscillating transcripts could be grouped coarsely into genes that were upregulated and downregulated in the dark period. The accumulated glycogen was degraded in the anaerobic environment in the dark. A small part was degraded gradually, reflecting basic maintenance requirements of the cells in darkness. Surprisingly, the largest part was degraded rapidly in a short time span at the end of the dark period. This degradation could allow rapid formation of metabolic intermediates at the end of the dark period, preparing the cells for the resumption of growth at the start of the light period.}, author = {Angermayr, Andreas and Van Alphen, Pascal and Hasdemir, Dicle and Kramer, Gertjan and Iqbal, Muzamal and Van Grondelle, Wilmar and Hoefsloot, Huub and Choi, Younghae and Hellingwerf, Klaas}, journal = {Applied and Environmental Microbiology}, number = {14}, pages = {4180 -- 4189}, publisher = {American Society for Microbiology}, title = {{Culturing synechocystis sp. Strain pcc 6803 with N2 and CO2 in a diel regime reveals multiphase glycogen dynamics with low maintenance costs}}, doi = {10.1128/AEM.00256-16}, volume = {82}, year = {2016}, } @article{1219, abstract = {We consider N×N random matrices of the form H = W + V where W is a real symmetric or complex Hermitian Wigner matrix and V is a random or deterministic, real, diagonal matrix whose entries are independent of W. We assume subexponential decay for the matrix entries of W, and we choose V so that the eigenvalues ofW and V are typically of the same order. For a large class of diagonal matrices V , we show that the local statistics in the bulk of the spectrum are universal in the limit of large N.}, author = {Lee, Jioon and Schnelli, Kevin and Stetler, Ben and Yau, Horngtzer}, journal = {Annals of Probability}, number = {3}, pages = {2349 -- 2425}, publisher = {Institute of Mathematical Statistics}, title = {{Bulk universality for deformed wigner matrices}}, doi = {10.1214/15-AOP1023}, volume = {44}, year = {2016}, } @article{122, abstract = {Four rigid panels connected by hinges that meet at a point form a four-vertex, the fundamental building block of origami metamaterials. Most materials designed so far are based on the same four-vertex geometry, and little is known regarding how different geometries affect folding behavior. Here we systematically categorize and analyze the geometries and resulting folding motions of Euclidean four-vertices. Comparing the relative sizes of sector angles, we identify three types of generic vertices and two accompanying subtypes. We determine which folds can fully close and the possible mountain-valley assignments. Next, we consider what occurs when sector angles or sums thereof are set equal, which results in 16 special vertex types. One of these, flat-foldable vertices, has been studied extensively, but we show that a wide variety of qualitatively different folding motions exist for the other 15 special and 3 generic types. Our work establishes a straightforward set of rules for understanding the folding motion of both generic and special four-vertices and serves as a roadmap for designing origami metamaterials.}, author = {Waitukaitis, Scott R and Van Hecke, Martin}, journal = {Physical Review E - Statistical, Nonlinear, and Soft Matter Physics}, number = {2}, publisher = {American Physiological Society}, title = {{Origami building blocks: Generic and special four-vertices}}, doi = {10.1103/PhysRevE.93.023003}, volume = {93}, year = {2016}, } @inproceedings{1220, abstract = {Theoretical and numerical aspects of aerodynamic efficiency of propulsion systems coupled to the boundary layer of a fuselage are studied. We discuss the effects of local flow fields, which are affected both by conservative flow acceleration as well as total pressure losses, on the efficiency of boundary layer immersed propulsion devices. We introduce the concept of a boundary layer retardation turbine that helps reduce skin friction over the fuselage. We numerically investigate efficiency gains offered by boundary layer and wake interacting devices. We discuss the results in terms of a total energy consumption framework and show that efficiency gains of any device depend on all the other elements of the propulsion system.}, author = {Mikić, Gregor and Stoll, Alex and Bevirt, Joe and Grah, Rok and Moore, Mark}, location = {Washington, D.C., USA}, pages = {1 -- 19}, publisher = {AIAA}, title = {{Fuselage boundary layer ingestion propulsion applied to a thin haul commuter aircraft for optimal efficiency}}, doi = {10.2514/6.2016-3764}, year = {2016}, } @article{1221, abstract = {The Auxin Binding Protein 1 (ABP1) is one of the most studied proteins in plants. Since decades ago, it has been the prime receptor candidate for the plant hormone auxin with a plethora of described functions in auxin signaling and development. The developmental importance of ABP1 has recently been questioned by identification of Arabidopsis thaliana abp1 knock-out alleles that show no obvious phenotypes under normal growth conditions. In this study, we examined the contradiction between the normal growth and development of the abp1 knock-outs and the strong morphological defects observed in three different ethanol-inducible abp1 knock-down mutants ( abp1-AS, SS12K, SS12S). By analyzing segregating populations of abp1 knock-out vs. abp1 knock-down crosses we show that the strong morphological defects that were believed to be the result of conditional down-regulation of ABP1 can be reproduced also in the absence of the functional ABP1 protein. This data suggests that the phenotypes in abp1 knock-down lines are due to the off-target effects and asks for further reflections on the biological function of ABP1 or alternative explanations for the missing phenotypic defects in the abp1 loss-of-function alleles.}, author = {Michalko, Jaroslav and Glanc, Matous and Perrot Rechenmann, Catherine and Friml, Jirí}, journal = {F1000 Research }, publisher = {F1000 Research}, title = {{Strong morphological defects in conditional Arabidopsis abp1 knock-down mutants generated in absence of functional ABP1 protein}}, doi = {10.12688/f1000research.7654.1}, volume = {5}, year = {2016}, } @article{1222, abstract = {We consider packings of congruent circles on a square flat torus, i.e., periodic (w.r.t. a square lattice) planar circle packings, with the maximal circle radius. This problem is interesting due to a practical reason—the problem of “super resolution of images.” We have found optimal arrangements for N=6, 7 and 8 circles. Surprisingly, for the case N=7 there are three different optimal arrangements. Our proof is based on a computer enumeration of toroidal irreducible contact graphs.}, author = {Musin, Oleg and Nikitenko, Anton}, journal = {Discrete & Computational Geometry}, number = {1}, pages = {1 -- 20}, publisher = {Springer}, title = {{Optimal packings of congruent circles on a square flat torus}}, doi = {10.1007/s00454-015-9742-6}, volume = {55}, year = {2016}, } @article{1223, abstract = {We consider a random Schrödinger operator on the binary tree with a random potential which is the sum of a random radially symmetric potential, Qr, and a random transversally periodic potential, κQt, with coupling constant κ. Using a new one-dimensional dynamical systems approach combined with Jensen's inequality in hyperbolic space (our key estimate) we obtain a fractional moment estimate proving localization for small and large κ. Together with a previous result we therefore obtain a model with two Anderson transitions, from localization to delocalization and back to localization, when increasing κ. As a by-product we also have a partially new proof of one-dimensional Anderson localization at any disorder.}, author = {Froese, Richard and Lee, Darrick and Sadel, Christian and Spitzer, Wolfgang and Stolz, Günter}, journal = {Journal of Spectral Theory}, number = {3}, pages = {557 -- 600}, publisher = {European Mathematical Society}, title = {{Localization for transversally periodic random potentials on binary trees}}, doi = {10.4171/JST/132}, volume = {6}, year = {2016}, } @article{1224, abstract = {Sexual dimorphism in resource allocation is expected to change during the life cycle of dioecious plants because of temporal differences between the sexes in reproductive investment. Given the potential for sex-specific differences in reproductive costs, resource availability may contribute to variation in reproductive allocation in females and males. Here, we used Rumex hastatulus, a dioecious, wind-pollinated annual plant, to investigate whether sexual dimorphism varies with life-history stage and nutrient availability, and determine whether allocation patterns differ depending on reproductive commitment. To examine if the costs of reproduction varied between the sexes, reproduction was either allowed or prevented through bud removal, and biomass allocation was measured at maturity. In a second experiment to assess variation in sexual dimorphism across the life cycle, and whether this varied with resource availability, plants were grown in high and low nutrients and allocation to roots, aboveground vegetative growth and reproduction were measured at three developmental stages. Males prevented from reproducing compensated with increased above- and belowground allocation to a much larger degree than females, suggesting that male reproductive costs reduce vegetative growth. The proportional allocation to roots, reproductive structures and aboveground vegetative growth varied between the sexes and among life-cycle stages, but not with nutrient treatment. Females allocated proportionally more resources to roots than males at peak flowering, but this pattern was reversed at reproductive maturity under low-nutrient conditions. Our study illustrates the importance of temporal dynamics in sex-specific resource allocation and provides support for high male reproductive costs in wind-pollinated plants.}, author = {Teitel, Zachary and Pickup, Melinda and Field, David and Barrett, Spencer}, journal = {Plant Biology}, number = {1}, pages = {98 -- 103}, publisher = {Wiley-Blackwell}, title = {{The dynamics of resource allocation and costs of reproduction in a sexually dimorphic, wind-pollinated dioecious plant}}, doi = {10.1111/plb.12336}, volume = {18}, year = {2016}, } @inproceedings{1225, abstract = {At Crypto 2015 Fuchsbauer, Hanser and Slamanig (FHS) presented the first standard-model construction of efficient roundoptimal blind signatures that does not require complexity leveraging. It is conceptually simple and builds on the primitive of structure-preserving signatures on equivalence classes (SPS-EQ). FHS prove the unforgeability of their scheme assuming EUF-CMA security of the SPS-EQ scheme and hardness of a version of the DH inversion problem. Blindness under adversarially chosen keys is proven under an interactive variant of the DDH assumption. We propose a variant of their scheme whose blindness can be proven under a non-interactive assumption, namely a variant of the bilinear DDH assumption. We moreover prove its unforgeability assuming only unforgeability of the underlying SPS-EQ but no additional assumptions as needed for the FHS scheme.}, author = {Fuchsbauer, Georg and Hanser, Christian and Kamath Hosdurg, Chethan and Slamanig, Daniel}, location = {Amalfi, Italy}, pages = {391 -- 408}, publisher = {Springer}, title = {{Practical round-optimal blind signatures in the standard model from weaker assumptions}}, doi = {10.1007/978-3-319-44618-9_21}, volume = {9841}, year = {2016}, } @article{1226, abstract = {Mitochondrial complex I (also known as NADH:ubiquinone oxidoreductase) contributes to cellular energy production by transferring electrons from NADH to ubiquinone coupled to proton translocation across the membrane. It is the largest protein assembly of the respiratory chain with a total mass of 970 kilodaltons. Here we present a nearly complete atomic structure of ovine (Ovis aries) mitochondrial complex I at 3.9 Å resolution, solved by cryo-electron microscopy with cross-linking and mass-spectrometry mapping experiments. All 14 conserved core subunits and 31 mitochondria-specific supernumerary subunits are resolved within the L-shaped molecule. The hydrophilic matrix arm comprises flavin mononucleotide and 8 iron-sulfur clusters involved in electron transfer, and the membrane arm contains 78 transmembrane helices, mostly contributed by antiporter-like subunits involved in proton translocation. Supernumerary subunits form an interlinked, stabilizing shell around the conserved core. Tightly bound lipids (including cardiolipins) further stabilize interactions between the hydrophobic subunits. Subunits with possible regulatory roles contain additional cofactors, NADPH and two phosphopantetheine molecules, which are shown to be involved in inter-subunit interactions. We observe two different conformations of the complex, which may be related to the conformationally driven coupling mechanism and to the active-deactive transition of the enzyme. Our structure provides insight into the mechanism, assembly, maturation and dysfunction of mitochondrial complex I, and allows detailed molecular analysis of disease-causing mutations.}, author = {Fiedorczuk, Karol and Letts, James A and Degliesposti, Gianluca and Kaszuba, Karol and Skehel, Mark and Sazanov, Leonid A}, journal = {Nature}, number = {7625}, pages = {406 -- 410}, publisher = {Nature Publishing Group}, title = {{Atomic structure of the entire mammalian mitochondrial complex i}}, doi = {10.1038/nature19794}, volume = {538}, year = {2016}, } @article{262, abstract = {For any number field we calculate the exact proportion of rational numbers which are everywhere locally a norm but not globally a norm from the number field.}, author = {Timothy Browning and Newton, Rachel}, journal = {Mathematika}, number = {2}, pages = {337 -- 347}, publisher = {Cambridge University Press}, title = {{The proportion of failures of the Hasse norm principle}}, doi = {10.1112/S0025579315000261}, volume = {62}, year = {2016}, } @article{263, abstract = {We count rational points of bounded height on the Cayley ruled cubic surface and interpret the result in the context of general conjectures due to Batyrev and Tschinkel.}, author = {de la Bretèche, Régis and Timothy Browning and Salberger, Per}, journal = {European Journal of Mathematics}, number = {1}, pages = {55 -- 72}, publisher = {Springer Nature}, title = {{Counting rational points on the Cayley ruled cubic}}, doi = {10.1007/s40879-015-0049-1}, volume = {2}, year = {2016}, } @article{264, abstract = {Given a family of varieties over a number field, we determine conditions under which there is a Brauer-Manin obstruction to weak approximation for 100% of the fibres which are everywhere locally soluble.}, author = {Bright, Maritn J and Timothy Browning and Loughran, Daniel}, journal = {Compositio Mathematica}, number = {7}, pages = {1435 -- 1475}, publisher = {Cambridge University Press}, title = {{Failures of weak approximation in families}}, doi = {10.1112/S0010437X16007405}, volume = {152}, year = {2016}, } @article{13385, abstract = {Novel light-responsive nanoparticles were synthesized by decorating the surfaces of gold and silver nanoparticles with a nitrospiropyran molecular photoswitch. Upon exposure to UV light in nonpolar solvents, these nanoparticles self-assembled to afford spherical aggregates, which disassembled rapidly when the UV stimulus was turned off. The sizes of these aggregates depended on the nanoparticle concentration, and their lifetimes could be controlled by adjusting the surface concentration of nitrospiropyran on the nanoparticles. The conformational flexibility of nitrospiropyran, which was altered by modifying the structure of the background ligand, had a profound impact on the self-assembly process. By coating the nanoparticles with a spiropyran lacking the nitro group, a conceptually different self-assembly system, relying on a reversible proton transfer, was realized. The resulting particles spontaneously (in the dark) assembled into aggregates that could be readily disassembled upon exposure to blue light.}, author = {Kundu, Pintu K. and Das, Sanjib and Ahrens, Johannes and Klajn, Rafal}, issn = {2040-3372}, journal = {Nanoscale}, keywords = {General Materials Science}, number = {46}, pages = {19280--19286}, publisher = {Royal Society of Chemistry}, title = {{Controlling the lifetimes of dynamic nanoparticle aggregates by spiropyran functionalization}}, doi = {10.1039/c6nr05959g}, volume = {8}, year = {2016}, } @article{13386, abstract = {Azobenzenealkanethiols in self-assembled monolayers (SAMs) on Au(111) exhibit reversible trans–cis photoisomerization when diluted with alkanethiol spacers. Using these mixed SAMs, we show switching of the linear optical and second-harmonic response. The effective switching of these surface optical properties relies on a reasonably large cross section and a high photoisomerization yield as well as a long lifetime of the metastable cis isomer. We quantified the switching process by X-ray absorption spectroscopy. The cross sections for the trans–cis and cis–trans photoisomerization with 365 and 455 nm light, respectively, are 1 order of magnitude smaller than in solution. In vacuum, the 365 nm photostationary state comprises 50–74% of the molecules in the cis form, limited by their rapid thermal isomerization back to the trans state. In contrast, the 455 nm photostationary state contains nearly 100% trans-azobenzene. We determined time constants for the thermal cis–trans isomerization of only a few minutes in vacuum and in a dry nitrogen atmosphere but of more than 1 day in ambient air. Our results suggest that adventitious water adsorbed on the surface of the SAM stabilizes the polar cis configuration of azobenzene under ambient conditions. The back reaction rate constants differing by 2 orders of magnitude underline the huge influence of the environment and, accordingly, its importance when comparing various experiments.}, author = {Moldt, Thomas and Przyrembel, Daniel and Schulze, Michael and Bronsch, Wibke and Boie, Larissa and Brete, Daniel and Gahl, Cornelius and Klajn, Rafal and Tegeder, Petra and Weinelt, Martin}, issn = {1520-5827}, journal = {Langmuir}, keywords = {Electrochemistry, Spectroscopy, Surfaces and Interfaces, Condensed Matter Physics, General Materials Science}, number = {42}, pages = {10795--10801}, publisher = {American Chemical Society}, title = {{Differing isomerization kinetics of azobenzene-functionalized self-assembled monolayers in ambient air and in vacuum}}, doi = {10.1021/acs.langmuir.6b01690}, volume = {32}, year = {2016}, } @article{13387, abstract = {Come on in, the water's fine! Non-photoresponsive nanoparticles can be reversibly assembled using light by placing them in an aqueous solution of a photo­acid. Upon exposure to visible light, the photoacid reduces the pH of the solution, which induces attractive interactions between the nanoparticles. In the dark, the resulting nanoparticle aggregates spontaneously disassemble. The process can be repeated many times.}, author = {Samanta, Dipak and Klajn, Rafal}, issn = {2195-1071}, journal = {Advanced Optical Materials}, keywords = {Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}, number = {9}, pages = {1373--1377}, publisher = {Wiley}, title = {{Aqueous light-controlled self-assembly of nanoparticles}}, doi = {10.1002/adom.201600364}, volume = {4}, year = {2016}, } @misc{13388, abstract = {The Inside Cover picture illustrates the fluorescent properties of a gold nanocluster functionalized with several copies of a red-emitting merocyanine (image by Ella Marushchenko). The red fluorescence can be turned on and off reversibly by using an external stimulus.}, author = {Udayabhaskararao, T. and Kundu, Pintu K. and Ahrens, Johannes and Klajn, Rafal}, booktitle = {ChemPhysChem}, issn = {1439-7641}, keywords = {Physical and Theoretical Chemistry, Atomic and Molecular Physics, and Optics}, number = {12}, pages = {1711--1711}, publisher = {Wiley}, title = {{Inside cover: Reversible photoisomerization of spiropyran on the surfaces of Au25 nanoclusters (ChemPhysChem 12/2016)}}, doi = {10.1002/cphc.201600480}, volume = {17}, year = {2016}, } @article{13389, abstract = {Au25 nanoclusters functionalized with a spiropyran molecular switch are synthesized via a ligand-exchange reaction at low temperature. The resulting nanoclusters are characterized by optical and NMR spectroscopies as well as by mass spectrometry. Spiropyran bound to nanoclusters isomerizes in a reversible fashion when exposed to UV and visible light, and its properties are similar to those of free spiropyran molecules in solution. The reversible photoisomerization entails the modulation of fluorescence as well as the light-controlled self-assembly of nanoclusters.}, author = {Udayabhaskararao, T. and Kundu, Pintu K. and Ahrens, Johannes and Klajn, Rafal}, issn = {1439-7641}, journal = {ChemPhysChem}, keywords = {Physical and Theoretical Chemistry, Atomic and Molecular Physics, and Optics}, number = {12}, pages = {1805--1809}, publisher = {Wiley}, title = {{Reversible photoisomerization of spiropyran on the surfaces of Au25 nanoclusters}}, doi = {10.1002/cphc.201500897}, volume = {17}, year = {2016}, }