12,545 results match your criteria: "14195 Berlin Germany; Helmholtz Virtual Institute[Affiliation]"

Switchable topological polar states in epitaxial BaTiO nanoislands on silicon.

Nat Commun

November 2024

Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109, Berlin, Germany.

A fascinating aspect of nanoscale ferroelectric materials is the emergence of topological polar textures, which include various complex and stable polarization configurations. The manipulation of such topological textures through external stimuli like electric fields holds promise for advanced nanoelectronics applications. There are, however, several challenges to reach potential applications, among which reliably creating and controlling these textures at the nanoscale on silicon, and with lead-free compounds.

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Article Synopsis
  • The study explores the growth and structure of ultrathin iron silicate and iron germanate films on a ruthenium substrate, focusing on how temperature affects their formation.
  • These two-dimensional films serve as simplified models for more complex, catalytically active structures like zeolites, which have applications as catalysts and molecular sieves.
  • Researchers used advanced experimental techniques for real-time analysis and theoretical modeling to reveal that both film systems consist of a two-layer structure, with distinct compositions impacting the arrangement and properties of iron atoms within the films.
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Herein, we performed a virtual screening study to discover new scaffolds for small molecule-based ligands of the immune checkpoint lymphocyte-activation gene 3 (LAG-3). Molecular dynamics (MD) simulations using the LAG-3 structure revealed two putative binding sites for small molecules: the antibody interface and the lipophilic canyon. A 3D pharmacophore screening resulted in the identification of potential ligands for these binding sites and afforded a library of 25 compounds.

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A profound understanding of protein structure and mechanism requires dedicated experimental and theoretical tools to elucidate electrostatic and hydrogen bonding interactions in proteins. In this work, we employed an approach to disentangle noncovalent and hydrogen-bonding electric field changes during the reaction cascade of a multidomain protein, i.e.

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Soft control: Furthering the case for Modified Interventionist Theory.

Stud Hist Philos Sci

December 2024

Institut für Philosophie, Freie Universität Berlin, Habelschwerdter Allee 30, 14195, Berlin, Germany; Department of Philosophy, University at Buffalo (North Campus), 211 Mary Talbert Way, Buffalo, NY 14260, United States of America. Electronic address:

Not all testing interventions that we might want to perform, or need to be performable in principle, fail to cause off-path variables. This is a problem for Woodward's Orthodox Interventionist Theory of causation, but not the 'Modified Interventionist Theory', which I proposed in a previous issue of this journal (Friend, 2021). As I explain here, this is because only the modified theory permits 'soft control'.

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Cultural evolution applies evolutionary concepts and tools to explain the change of culture over time. Despite advances in both theoretical and empirical methods, the connections between cultural evolutionary theory and evidence are often vague, limiting progress. Theoretical models influence empirical research but rarely guide data collection and analysis in logical and transparent ways.

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Orthogonal Functionalization of Oxo-Graphene Nanoribbons.

Chemistry

January 2025

Institute of Chemistry and Biochemistry, Freie Universität Berlin, Altensteinstraße 23a, 14195, Berlin, Germany.

Article Synopsis
  • Oxo-graphene nanoribbons (oxo-GNRs) are created by cutting single-walled carbon nanotubes through an oxidative process.
  • An orthogonal functionalization method is introduced that allows for modifications on both the edges and the flat surface of oxo-GNRs due to their unique structure.
  • This functionalization technique, which was tracked using X-ray photoelectron spectroscopy, can also be adapted for other oxo-functionalized carbon materials like graphene quantum dots and reduced graphene oxide.
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Menstrual cycle related depressive symptoms and their diurnal fluctuations - an ambulatory assessment study.

BMC Womens Health

November 2024

Division of Clinical Psychological Intervention, Department of Education and Psychology, Freie Universität Berlin, Schwendenerstraße 27, Berlin, 14195, Germany.

Background: Reproductive mood disorders indicate that within-person variation in depressive symptoms across the menstrual cycle can be related to ovarian hormone changes. Until now, such cycle-related symptom changes have been measured once daily, even though depression research indicates systematic diurnal changes in symptoms. Further, previous research often focused on aggregated depression scores.

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Alpha-helical membrane proteins perform numerous critical functions essential for the survival of living organisms. Traditionally, these proteins are extracted from membranes using detergent solubilization and reconstitution into liposomes or nanodiscs. However, these processes often obscure the effects of nanoconfinement and the native environment on the structure and conformational heterogeneity of the target protein.

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Predictors of explicit and implicit anthropomorphism in house facades.

Sci Rep

November 2024

Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, AG Neuronale Plastizität, Gebäude W37, Martinistr. 52, 20246, Hamburg, Germany.

Anthropomorphism describes the tendency to endow objects with human characteristics, with some individuals being more inclined to do this than others. In an ambiguous environment, this phenomenon can offer guidance. This study investigates the relationship between self-reported attribution and evoked anthropomorphism when viewing house facades.

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Background And Hypothesis: The efficacy of yoga as an adjunctive treatment for schizophrenia spectrum disorders (SSD) has garnered interest. While yoga may positively influence various symptom domains, further investigation is needed due to the limited number, quality, and generalizability of studies. This study assessed the feasibility and acceptability (primary outcome) of a yoga-based group intervention (YoGI) developed in a participatory approach and explored its preliminary effectiveness.

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Article Synopsis
  • - The orbitofrontal cortex (OFC) and ventromedial-prefrontal cortex (vmPFC) are crucial for decision-making, representing not just expected value but also various task states by integrating different types of information such as stimuli, context, and outcomes.
  • - Evidence shows that the way these brain regions encode information mirrors the complex representations found in advanced deep reinforcement learning models, where single nodes can flexibly combine multiple types of data.
  • - Key questions remain about how OFC/vmPFC contribute to learning across different tasks, how they handle irrelevant information, and the interactions between the hippocampus and prefrontal cortex.
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pH Modulates Friction Memory Effects in Protein Folding.

Phys Rev Lett

November 2024

Freie Universität Berlin, Fachbereich Physik, 14195 Berlin, Germany.

Protein folding is an intrinsically multitimescale problem. While it is accepted that non-Markovian effects are present on short timescales, it is unclear whether memory-dependent friction influences long-timescale protein folding reaction kinetics. We combine friction memory-kernel extraction techniques with recently published extensive all-atom simulations of the α3D protein under neutral and reduced pH conditions, and we show that the pH reduction modifies the friction acting on the folding protein by dramatically decreasing the friction memory decay time.

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Role of the Coulomb Potential in Compton Scattering.

Phys Rev Lett

November 2024

Institut für Kernphysik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany.

We report a fully differential study of ionization of the Ne L shell by Compton scattering of 20 keV photons. We find two physical mechanisms that modify the Compton-electron emission. Firstly, we observe scattering of the Compton electrons at their parent nucleus.

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How do people search for information when they are given the opportunity to freely explore their options? Previous research has suggested that people focus on reducing uncertainty before making a decision, but it remains unclear how exactly they do so and whether they do so consistently. We present an analysis of over 1,000,000 information-search decisions made by over 2,500 individuals in a decisions-from-experience setting that cleanly separates information search from choice. Using a data-driven approach supported by a formal measurement framework, we examine how people allocate samples to options and how they decide to terminate search.

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Changes in Secondary Structure Upon Pr to Pfr Transition in Cyanobacterial Phytochrome Cph1 Detected by DNP NMR.

Chemistry

January 2025

NMR-supported Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125, Berlin, Germany.

Phytochromes perceive subtle changes in the light environment and convert them into biological signals by photoconversion between the red-light absorbing (Pr) and the far-red-absorbing (Pfr) states. In the primitive bacteriophytochromes this includes refolding of a tongue-like hairpin loop close to the chromophore, one strand of an antiparallel β-sheet being replaced by an α-helix. However, the strand sequence in the cyanobacterial phytochrome Cph1 is different from that of previously investigated bacteriophytochromes and has a higher β-sheet propensity.

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A permanently available molecular-beam injection setup for controlled molecules (COMO) was installed and commissioned at the small quantum systems (SQS) instrument at the European x-ray free-electron laser (EuXFEL). A b-type electrostatic deflector allows for pure state-, size-, and isomer-selected samples of polar molecules and clusters. The source provides a rotationally cold (T ≈ 1 K) and dense (ρ ≈ 108 cm-3) molecular beam with pulse durations up to 100 µs generated by a new version of the Even-Lavie valve.

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From Gas to Solution: The Changing Neutral Structure of Proline upon Solvation.

J Phys Chem A

November 2024

Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, Berlin 14195, Germany.

Liquid-jet photoelectron spectroscopy (LJ-PES) and electronic-structure theory were employed to investigate the chemical and structural properties of the amino acid l-proline in aqueous solution for its three ionized states (protonated, zwitterionic, and deprotonated). This is the first PES study of this amino acid in its biologically relevant environment. Proline's structure in the aqueous phase under neutral conditions is zwitterionic, distinctly different from the nonionic neutral form in the gas phase.

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Spatially resolved transcriptomics (SRT) has become the method of choice for characterising the complexity of biomedical tissue samples. Until recently, scientists were restricted to SRT methods that can profile a limited set of target genes at high spatial resolution or transcriptome-wide but at a low spatial resolution. Through recent developments, there are now methods that offer both subcellular spatial resolution and full transcriptome coverage.

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The photoisomerization rate of -stilbene (tS) and trans-trans-diphenylbutadiene (ttD) is studied in solution and compared to that in jet/gas. Rice-Ramsperger-Kassel-Marcus (RRKM) theory correctly predicts the tS rate in jet, = exp(-/) with = 1398 cm, and = 1.8 ps corresponding to frequency ν = 60 cm of the reactive mode, being the molecular temperature.

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Nearly five billion people use and receive news through social media and there is widespread concern about the negative consequences of misinformation on social media (e.g., election interference, vaccine hesitancy).

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Several diatomic transition metal oxides, rare-earth metal oxides, and fluorides have the unusual property that their bond dissociation energy is larger than their ionization energy. In these molecules, bound levels above the ionization energy can be populated via strong, resonant transitions from the ground state. The only relevant decay channel of these levels is autoionization; predissociation is energetically not possible and radiative decay is many orders of magnitude slower.

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Photocatalytic Magnetic Microgyroscopes with Activity-Tunable Precessional Dynamics.

Nano Lett

November 2024

Departament de Física de la Matèria Condensada, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain.

Magnetic nano/microrotors are passive elements spinning around an axis due to an external rotating field while remaining confined to a plane. They have been used to date in different applications related to fluid mixing, drug delivery, or biomedicine. Here we realize an active version of a magnetic microgyroscope which is simultaneously driven by a photoactivated catalytic reaction and a rotating magnetic field.

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Reactivity and Stability of Reduced Ir-Weight TiO-Supported Oxygen Evolution Catalysts for Proton Exchange Membrane (PEM) Water Electrolyzer Anodes.

J Am Chem Soc

November 2024

Department of Chemistry, Chemical Engineering Division, The Electrochemical Energy, Catalysis and Materials Science Laboratory, Technische Universität Berlin, Straße des 17. Juni 124, 10623 Berlin, Germany.

Reducing the iridium demand in Proton Exchange Membrane Water Electrolyzers (PEM WE) is a critical priority for the green hydrogen industry. This study reports the discovery of a TiO-supported Ir@IrO(OH) core-shell nanoparticle catalyst with reduced Ir content, which exhibits superior catalytic performance for the electrochemical oxygen evolution reaction (OER) compared to a commercial reference. The TiO-supported Ir@IrO(OH) core-shell nanoparticle configuration significantly enhances the OER Ir mass activity from 8 to approximately 150 A g at 1.

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High Chern number quantum anomalous Hall effect in monolayer CoXSSe (X = Sn, Pb) kagomes.

Phys Chem Chem Phys

November 2024

Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang, 110819, China.

The high Chern number quantum anomalous Hall effect can offer an ideal platform to develop exotic quantum materials with a dissipationless chiral edge. The investigation of kagome monolayer CoXSSe (X = Sn, Pb) materials enables a comprehensive exploration of their structural, magnetoelectric, and topological characteristics through first-principles calculations. The monolayers CoSnSSe and CoPbSSe are classified as kagome ferromagnets, and they exhibit stable perpendicular magnetic anisotropy energy.

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