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Structural basis of Nipah virus RNA synthesis
No full textAbstract Nipah virus (NiV) is a non-segmented negative-strand RNA virus (nsNSV) with high pandemic potential, as it frequently causes zoonotic outbreaks and can be transmitted from human to human. Its RNA-dependent RNA polymerase (RdRp) complex, consisting of the L and P proteins, carries out viral genome replication and transcription and is therefore an attractive drug target. Here, we report cryo-EM structures of the NiV polymerase complex in the apo and in an early elongation state with RNA and incoming substrate bound. The structure of the apo enzyme reveals the architecture of the NiV L-P complex, which shows a high degree of similarity to other nsNSV polymerase complexes. The structure of the RNA-bound NiV L-P complex shows how the enzyme interacts with template and product RNA during early RNA synthesis and how nucleoside triphosphates are bound in the active site. Comparisons show that RNA binding leads to rearrangements of key elements in the RdRp core and to ordering of the flexible C-terminal domains of NiV L required for RNA capping. Taken together, these results reveal the first structural snapshots of an actively elongating nsNSV L-P complex and provide insights into the mechanisms of genome replication and transcription by NiV and related viruses.Open-Access-Publikationsfonds 202
Spray Deposition for Solvent Annealing of Hybrid Poly(3,4‐Ethylenedioxythiophene) Polystyrene Sulfonate Cellulose Silver Nanowire Composite Electrodes Using a Roll‐to‐Roll Coater
No full textSpray deposition is a rapid and facile technique for coating surfaces on a large scale. The quality of these coatings can be improved via post‐treatment. One example is solvent annealing, a well‐known strategy to enhance the conductivity of polymeric electrode materials using organic solvents. Herein, the annealing of sprayed poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)‐based electrodes via solvent spray deposition in a single roll‐to‐roll setup is reported. The annealing rates of three solvents, namely dimethyl sulfoxide (DMSO), isopropanol (IPA), and methanol (MeOH), depending on the spray time and sprayed volume, are evaluated and correlated with structural changes. The results show that the applied method reduces the sheet resistance ( R s ) of pure PEDOT:PSS films by 82% using DMSO and of cellulose‐based silver nanowire‐PEDOT:PSS electrodes by 50% using MeOH. This approach allows for the facile and effective combination of fabrication and quality enhancement of sprayed, conductive polymer films using only one piece of equipment. This approach makes the overall production process of organic electrodes faster and cheaper and therefore the usage of sustainable materials and fabrication methods more attractive for the industry.Deutsches Elektronen-Synchrotron https://doi.org/10.13039/501100001647Deutsche Forschungsgemeinschaft https://doi.org/10.13039/50110000165
Preparation, maintenance and propagation of synchronous cultures of photoactive Chlamydomonas cells
No full textTetratic phase in 2D crystals of squares
No full textWe report the tetratic phase as an intermediate phase between an isotropic fluid and a square crystal composed of micrometer sized squares in two dimensions. The squares are manufactured by direct laser writing in a photoresist.Melting in two-dimensional (2D) systems is described by the celebrated Kosterlitz–Thouless–Halperin–Nelson–Young (KTHNY) theory, which explains how the unbinding of two types of topological defects destroys translational and orientational order at distinct temperatures. The intermediate hexatic phase, a fluid with six-fold quasi-long-ranged orientational order, has been observed in 2D colloidal monolayers of isotropic particles. In this study, we investigate the melting of a quadratic crystal with four-fold symmetry, composed of square particles of approximately 4 × 4 μm in size. These anisotropic particles were fabricated from photoresist using 3D nanoprinting. In an aqueous solution, the particles sediment onto a cover slide, forming a monolayer. The adjustable curvature of the cover slide precisely controls the monolayer density. At low densities, the particles exhibit free diffusion, forming a 2D fluid, while at high densities, they assemble into a quadratic crystal. Using a four-fold bond-order correlation function, we identify the tetratic phase with quasi-long ranged orientational order in close analogy to the hexatic phase in systems with six-fold symmetry.We report the tetratic phase as an intermediate phase between an isotropic fluid and a square crystal composed of micrometer sized squares in two dimensions. The squares are manufactured by direct laser writing in a photoresist.Melting in two-dimensional (2D) systems is described by the celebrated Kosterlitz–Thouless–Halperin–Nelson–Young (KTHNY) theory, which explains how the unbinding of two types of topological defects destroys translational and orientational order at distinct temperatures. The intermediate hexatic phase, a fluid with six-fold quasi-long-ranged orientational order, has been observed in 2D colloidal monolayers of isotropic particles. In this study, we investigate the melting of a quadratic crystal with four-fold symmetry, composed of square particles of approximately 4 × 4 μm in size. These anisotropic particles were fabricated from photoresist using 3D nanoprinting. In an aqueous solution, the particles sediment onto a cover slide, forming a monolayer. The adjustable curvature of the cover slide precisely controls the monolayer density. At low densities, the particles exhibit free diffusion, forming a 2D fluid, while at high densities, they assemble into a quadratic crystal. Using a four-fold bond-order correlation function, we identify the tetratic phase with quasi-long ranged orientational order in close analogy to the hexatic phase in systems with six-fold symmetry.Deutsche Forschungsgemeinschaft https://doi.org/10.13039/50110000165
Response to “Comment on ‘Microcanonical treatment of HCl dissociative chemisorption on Au(111): Reactive dampening through inefficient translational energy coupling and an active surface’” [J. Chem. Phys. 162, 087101 (2025)]
No full textNational Science Foundation 10.13039/10000000
Attosecond microscopy —Advances and outlook
No full textAbstract Attosecond microscopy aims to record electron movement on its natural length and time scale. It is a gateway to understanding the interaction of matter and light, the coupling between excitations in solids, and the resulting energy flow and decoherence behavior, but it demands simultaneous temporal and spatial resolution. Modern science has conquered these scales independently, with ultrafast light sources providing sub-femtosecond pulses and advanced microscopes achieving sub-nanometer resolving power. In this perspective, we inspect the challenges raised by combining extreme temporal and spatial resolution and then highlight how upcoming experimental techniques overcome them to realize laboratory-scale attosecond microscopes. Referencing proof-of-principle experiments, we delineate the techniques’ strengths and their applicability to observing various ultrafast phenomena, materials, and sample geometries.Knut och Alice Wallenbergs Stiftelse https://doi.org/http://dx.doi.org/10.13039/501100004063Vetenskapsrådet https://doi.org/http://dx.doi.org/10.13039/501100004359Deutsche Forschungsgemeinschaft https://doi.org/http://dx.doi.org/10.13039/501100001659Deutsche Forschungsgemeinschaft https://doi.org/http://dx.doi.org/10.13039/501100001659H2020 European Research Council https://doi.org/http://dx.doi.org/10.13039/100010663Niedersächsisches Ministerium für Wissenschaft und Kultur https://doi.org/http://dx.doi.org/10.13039/501100010570Air Force Office of Scientific Research https://doi.org/http://dx.doi.org/10.13039/10000018
The spatial buildup of nonlinear compression in the cochlea
No full textIn the mammalian cochlea, the transduction from vibrations to inner hair cell receptor currents is preceded by a stage of mechanical pre-processing that involves a rapid, strongly nonlinear compression. The mechanisms by which the cochlea realizes this dynamic compression are still poorly understood. Previous work by our group suggested that compression does not occur locally, but is realized by a cascade of weakly nonlinear elements along the cochlear partition. The resulting progressive accumulation of nonlinearity was termed the spatial buildup of compression. Here we studied mechanical compression in the basal turn of the sensitive gerbil cochlea using optical coherence tomography. We recorded vibrations at multiple positions along the length of the cochlear partition. Such longitudinal studies were virtually impossible with previous techniques. Using a tailored two-tone stimulus we quantified the spatial profile of compression. We found that the amount of compression grew gradually in an intensity-dependent fashion along our measurement stretch, as we moved apically toward the place of maximum vibration. This gradual buildup of compression was not mirrored by a gradual reduction beyond the peak. In fact the amount of compression accumulated even beyond the peak. This asymmetric pattern supports the view that mechanical compression is realized in a cascaded, distributed fashion which hinges on the traveling wave nature of cochlear vibrations
Immune genes involved in synaptic plasticity during early postnatal brain development contribute to post-stroke damage in the aging male rat brain
No full textGenomic Scale Analysis Foresees Enteroprotective and Butyrogenic Properties in Brazilian Isolates of Lactiplantibacillus plantarum
No full textFoundation for the Support to Research in Minas GeraisCoordination for the Improvement of Higher Education Personnel http://dx.doi.org/10.13039/50110000232