The detection and localization of a source hidden outside the Line-of-Sight (LOS) traditionally rely on the acquisition of indirect signals, such as those reflected from visible relay surfaces such as floors or walls. These reflected signals are then utilized to reconstruct the obscured scene. In this study, we present an approach that utilize signals diffracted from an edge of an obstacle to achieve three-dimensional (3D) localization of an acoustic point source situated outside the LOS. We address two scenarios - a doorway and a convex corner - and propose a localization method for each of them. For the first scenario, we utilize the two edges of the door as virtual detector arrays. For the second scenario, we exploit the spectral signature of a knife-edge diffraction, inspired by the human perception of sound location by the head-related transfer function (HRTF). In both methods, knife-edge diffraction is utilized to extend the capabilities of non-line-of-sight (NLOS) acoustic sensing, enabling localization in environments where conventional relay-surface based approaches may be limited.
In this study, we report a photocatalytic late-stage decarboxylative functionalization strategy utilizing gem-boryl,silyl (gem-B,Si) alkene as a versatile coupling partner. This light-driven transformation enables the direct conversion of structurally simple and complex carboxylic acids into synthetically valuable molecules with Csp³ carbon bearing both Bpin and SiMe₃ groups under mild conditions. This methodology provides a powerful platform for the selective, programmable, late-stage modification of bioactive molecules, natural products, and fatty acid derivatives, enabling access to a diverse array of functionalized, chiral Csp³-rich molecules with potential applications across materials science and chemistry.
Traditional agenda-setting research often focuses on the most urgent problems that dominate present public agendas. Challenging the prevalent conflation of importance with urgency in agenda-setting research, this article proposes a shift from a singular to a layered temporal conceptualization of public agendas. The suggested framework distinguishes between the immediate agenda, which addresses problems perceived as most urgent, and the delayed agenda, which focuses on issues deemed most important for the future. Enriching agenda-setting theory with insights from construal level theory, the study examines the psychological and media-related factors shaping the placement of topics on these agendas. Drawing upon original survey data and a large-scale news content analysis from the French 2022 Presidential Elections, as well as survey data from the 2023 to 2024 war in Israel and Gaza, the findings provide empirical support for the proposed framework. The results indicate that participants prioritize psychologically proximate issues on the immediate agenda, whereas psychologically distant issues gain importance on the delayed agenda. Additionally, we identify media agenda-setting effects that extend beyond the immediate temporal layer. Specifically, both studies provide evidence for a media priming effect, where news exposure increases issue salience without affecting temporal layering. The Israeli case reveals additional initial evidence for an urgency effect, where news exposure boosts issue salience of some issues primarily on the immediate agenda. Overall, the study contributes to a deeper understanding of public agendas and news media effects, introducing a temporally nuanced perspective that enriches classical approaches to agenda-setting research.
Digital media constitute a key space for the negotiation of public opinion. Despite long-standing research on public opinion climates on digital media, little theory exists that considers their emergence and discursive dynamics. In this article, we conceptualize public opinion as a discursive process, which revolves around the public negotiation of normatively acceptable opinions. Reviewing and updating theoretical work on public opinion negotiations in pre-digital media, we examine how digital media have transformed this discursive process. Focusing on a) the public expression of b) normative opinions upon public issues by c) positioned speakers, resulting in d) the public negotiation of acceptable stances e) within public arenas governed by institutional and socio-technical media logics, we propose a theory of public opinion negotiations in a digital media ecosystem. Based on our conceptualization, we discuss operational implications for the empirical study of public opinion processes on digital media.
Cyclodextrins are widely used pharmaceutical excipients known to increase the solubility of drug compounds through formation of inclusion complexes. A prominent limitation of common cyclodextrins is their own scarce solubility in water, which renders them unsuitable for many drug formulations. Cyclodextrin solubility can be enhanced in appropriate media such as Deep Eutectic Solvents (DESs). However, DESs can also reduce the equilibrium constant for host-guest complexation, making it challenging to optimize drug solubility using cyclodextrin. To determine the impact and mechanism of cyclodextrin complexation in DES, we tracked changes in the solubility of methyl orange (MO), serving as a hardly soluble model compound, in the presence of β-cyclodextrin (CD) in hydrated urea-choline chloride DES. The highest achievable MO solubility is obtained in concentrated CD-in-DES mixtures at low hydration, resulting from the higher solubility of CD⊃MO complexes in DES compared to water as a solvent. Combining our results with molecular dynamics simulations, we provide evidence that CD⊃MO complexes self-associate into dimers and larger oligomers. This self-association of complexes greatly enhances MO solubilization by CD beyond that expected from the canonical 1:1 binding stoichiometry. This newly unraveled solubilization mechanism via cyclodextrins and its facilitation by DES should aid the design of future drug formulations.
This study examines the role of spontaneous intergroup contact in fostering social resilience in ethnically mixed urban settings, focusing on Israeli mixed cities. Based on a survey conducted in September 2021 involving 944 residents of diverse city types and a university survey of Jewish and Palestinian students, it explores the extent to which unmediated, unplanned interactions (spontaneous contact) among individuals from different ethnic and social backgrounds predicts their ability to cope with and recover from outbreaks of ethnic violence. Key findings indicate that residents of mixed cities show more favorable attitudes towards outgroup members than those in homogeneous cities, suggesting that spontaneous contact reduces prejudice. The study reveals a correlation between higher social proximity to outgroup members and lower levels of tension during periods of conflict. Unexpectedly, a decrease in social proximity among university students was observed over the course of an academic year, potentially due to the eruption of interethnic violence. However, students who experience frequent spontaneous contact displayed greater resilience, maintaining positive attitudes amidst conflict. This research underscores the significance of spontaneous contact in mixed cities and heterogeneous environments in promoting social resilience and a sense of coexistence. It suggests that everyday interactions in diverse environments are crucial for managing and mitigating the impacts of intergroup tensions and conflicts.
The Lindblad master equation is a fundamental tool for describing the evolution of open quantum systems, but its computational complexity poses a significant challenge, especially for large systems. This article introduces a stochastic representation of the Lindblad dissipator that addresses this challenge by bundling the Lindblad operators. The stochastic dissipator maintains the Lindblad form, ensuring completely positive and trace-preserving dynamics. We demonstrate the effectiveness of this method by considering a Morse oscillator coupled to a spin bath. Our numerical experiments show that a small number of stochastically bundled operators can accurately capture the system’s dynamics, even when the Hilbert space dimension is large. This method offers a new perspective on open quantum systems and provides a computationally efficient way to simulate their dynamics.
Microtubules (MTs) are one of the major components of the cytoskeleton. They are involved in many key functions of eukaryotic cells, including cell division, intracellular transport, cell motility, and cell shape. MTs are hollow tubules made of parallel filaments, formed by active (non-equilibrium) self-organization of tubulin dimers. The dynamic self-organization of tubulin is facilitated by the GTPase activity of tubulin. Tubulin self-assembles with microtubule-associated proteins (MAPs) and other factors into a wide range of morphologies, including tubulin rings, MT bundles, and the spindle apparatus, segregating chromosomes during cell division. In this review, we shall discuss recent insight into the intimate link between tubulin -biochemistry, -structure, -interactions, -dynamics, -stability, -assembly, -disassembly, and -mechanical properties. We shall then focus on recent time-resolved solution X-ray scattering analysis of tubulin self-organization below and above the critical conditions for microtubule assembly. Finally, we shall discuss some of the challenging multiscale unsolved problems requiring the integration of different experimental and theoretical methods. Microtubule formation is an important target for drugs to treat conditions like gout and a wide range of cancers. Understanding the polymerization mechanism could help in the design of future drugs and in the development of active biomaterials that promote the remodeling or regeneration of tissue after disease or injury.
Metallic nanowire (NW) arrays are promising components for nanotechnology owing to their elongated, continuous, and directional structure. Bimetallic NWs present synergistic effects that are advantageous for applications in catalysis and magnetism. Yet, creating bimetallic NW arrays requires concomitant control over composition and organization. Block copolymer films, which exhibit periodic arrays of nano-domains, provide templates that satisfy this requirement. Impregnating the film using two metal precursors followed by plasma treatment enabled us to prepare NW arrays with different bimetallic compositions. The NW composition was found to depend on the composition of the impregnation solution in a nontrivial way, which was strongly influenced by the type of metals used. Studying the behavior of three model metal pairs unraveled different characteristic co-impregnation behaviors, which we could associate with metal-ligand and metal-metal interactions. The insights gained in this study allow us to create bimetallic NW arrays with compositions tailored to the desired properties.
Proton-transfer dynamics in hydrogen-bonded dimers are important for understanding debated mechanisms of radiation damage to DNA base pairs. Using coincidence photofragment imaging in ultrafast extreme-ultraviolet pump and near-IR probe experiments on the formic acid dimer, we observed a transient enhancement (150 fs) of the protonated monomer signal. This correlates with ab initio molecular dynamics simulations of the ionization induced dynamics, showing concerted proton transfer and dimer ring opening in a metastable dimer. Coincidence analysis revealed the ultraslow mechanism of the metastable dimer cation on the microsecond time scale. The ultraslow dynamics were attributed to a barrier for the structural rearrangement of the deprotonated moiety from an HCOO to an OCOH geometry. Moreover, ultraslow channels of protonated monomer ions to form H3O+ + CO and H2O + CHO+ were observed and interpreted as dissociation of hot photoions, involving nontrivial hydrogen migration.
