447 research outputs found

    Growth and characterization of multiferroic BiMnO3_3 thin films

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    We have grown epitaxial thin films of multiferroic BiMnO3_3 using pulsed laser deposition. The films were grown on SrTiO3_3 (001) substrates by ablating a Bi-rich target. Using x-ray diffraction we confirmed that the films were epitaxial and the stoichiometry of the films was confirmed using Auger electron spectroscopy. The films have a ferromagnetic Curie temperature (TCT_C) of 85±\pm5 K and a saturation magnetization of 1 μB\mu_B/Mn. The electric polarization as a function of electric field (P−EP-E) was measured using an interdigital capacitance geometry. The P−EP-E plot shows a clear hysteresis that confirms the multiferroic nature of the thin films.Comment: 4 pages, 4 figures, submitted to J. Appl. Phy

    The Effect of Language Type and Perceived Controllability on Stigma and Compassion

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    Previous research suggests that mental health stigma creates significant barriers to treatment seeking and adherence, diminishes treatment outcomes, and motivates social rejection towards people experiencing mental illness; by contrast, compassion seems to offer protective effects, improving treatment outcomes and helping behavior. The current work extends the established literature by experimentally examining the independent and interactive effects of two factors theorized to influence stigma and compassion: controllability and language. Participants read vignettes about hypothetical mental illnesses explained with a genetic attribution (indicating low controllability) or a behavioral attribution (indicating high controllability) and completed measures of perceived controllability, stigma, and compassion. We found that genetic etiology, compared to behavioral etiology, decreased stigma and increased compassion. Although not statistically significant, preliminary evidence suggests that language might interact with etiology to affect stigma. In the behavioral etiology condition, identity-first language (compared to person-first) exacerbated stigma, whereas, in the genetic etiology condition, this effect was descriptively reversed, though statistically nonsignificant. Our findings provide evidence that emphasizing the contribution of uncontrollable factors (e.g., genetics) to psychopathology could help reduce stigma and increase compassion for people experiencing mental illness. Language may also interact with controllability to inform stigma. This work could aid in advising empathetic and supportive language practices dependent on condition characteristics (e.g., perceived controllability), however, replication is needed to demonstrate the reliability of these effects

    General Principles for the Design of Visible-Light-Responsive Photoswitches:Tetra-ortho-Chloro-Azobenzenes

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    Molecular photoswitches enable reversible external control of biological systems, nanomachines, and smart materials. Their development is driven by the need for low energy (green-red-NIR) light switching, to allow non-invasive operation with deep tissue penetration. The lack of clear design principles for the adaptation and optimization of such systems limits further applications. Here we provide a design rulebook for tetra-ortho-chloroazobenzenes, an emerging class of visible-light-responsive photochromes, by elucidating the role that substituents play in defining their key characteristics: absorption spectra, band overlap, photoswitching efficiencies, and half-lives of the unstable cis isomers. This is achieved through joint photochemical and theoretical analyses of a representative library of molecules featuring substituents of varying electronic nature. A set of guidelines is presented that enables tuning of properties to the desired application through informed photochrome engineering

    Local Anisotropy of Fluids using Minkowski Tensors

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    Statistics of the free volume available to individual particles have previously been studied for simple and complex fluids, granular matter, amorphous solids, and structural glasses. Minkowski tensors provide a set of shape measures that are based on strong mathematical theorems and easily computed for polygonal and polyhedral bodies such as free volume cells (Voronoi cells). They characterize the local structure beyond the two-point correlation function and are suitable to define indices 0≤βνa,b≤10\leq \beta_\nu^{a,b}\leq 1 of local anisotropy. Here, we analyze the statistics of Minkowski tensors for configurations of simple liquid models, including the ideal gas (Poisson point process), the hard disks and hard spheres ensemble, and the Lennard-Jones fluid. We show that Minkowski tensors provide a robust characterization of local anisotropy, which ranges from βνa,b≈0.3\beta_\nu^{a,b}\approx 0.3 for vapor phases to βνa,b→1\beta_\nu^{a,b}\to 1 for ordered solids. We find that for fluids, local anisotropy decreases monotonously with increasing free volume and randomness of particle positions. Furthermore, the local anisotropy indices βνa,b\beta_\nu^{a,b} are sensitive to structural transitions in these simple fluids, as has been previously shown in granular systems for the transition from loose to jammed bead packs

    The ELSA trial: single versus combinatory effects of non-prohibited beta-2 agonists on skeletal muscle metabolism, cardio-pulmonary function and endurance performance—study protocol for a randomized 4-way balanced cross-over trial

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    Background Asthma and/or airway hyper-responsiveness (AHR) are common in elite endurance athletes with a high prevalence rate of beta-2 adrenoreceptor (beta-2) agonists use. Nevertheless, there are data on dose-dependent ergogenic effects of beta-2 agonists suggesting increased muscle strength, endurance and neuromuscular performance. Therefore, most beta-2 agonists belong to the World Anti Doping Agency (WADA) list of prohibited substances and it is tempting to speculate that illegitimate use of beta-2 agonists might be a common practice to boost performance in competitive sports. It is currently unknown whether or not inhaled beta-2 agonists enhance performance by stimulatory effects in skeletal and cardiac muscle. Methods The ELSA trial is a double-blinded, placebo-controlled, randomized, balanced, four-way cross-over study. Study participants (n=24, 12 ♀, 12 ♂) complete four study arms (i.e. periods with treatment A, placebo; B, salbutamol; C, formoterol; D, formoterol + salbutamol) in random order after an initial preliminary testing session. Participants inhale the study medication 20 min before the 10-min time trial (TT; exercise performance test), where participants cycle 10 min at the highest possible workload. Cardiac output is measured continuously. A skeletal muscle biopsy is collected 3 h after the TT. Study endpoints include measures of skeletal muscle expression of nuclear receptors, hormones and cytokine levels, urinary and plasma concentrations of salbutamol and formoterol, circulating cardiac markers, cardiopulmonary function and exercise performance (average power and peak power during the TT). Blood and urine are collected and respiratory testing is performed 24 h post TT. Summary/conclusions This clinical trial evaluates the potential performance-enhancing effects of non-prohibited, not medically indicated inhaled short- and long-acting beta-2 agonists on skeletal muscle gene expression, endocrine regulation, cardiac biomarkers, cardiopulmonary function and acute endurance exercise performance. These data will be used by WADA to adapt the annually published list of prohibited substances (WADA 2021) and will be published in scientific journals

    Minkowski Tensors of Anisotropic Spatial Structure

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    This article describes the theoretical foundation of and explicit algorithms for a novel approach to morphology and anisotropy analysis of complex spatial structure using tensor-valued Minkowski functionals, the so-called Minkowski tensors. Minkowski tensors are generalisations of the well-known scalar Minkowski functionals and are explicitly sensitive to anisotropic aspects of morphology, relevant for example for elastic moduli or permeability of microstructured materials. Here we derive explicit linear-time algorithms to compute these tensorial measures for three-dimensional shapes. These apply to representations of any object that can be represented by a triangulation of its bounding surface; their application is illustrated for the polyhedral Voronoi cellular complexes of jammed sphere configurations, and for triangulations of a biopolymer fibre network obtained by confocal microscopy. The article further bridges the substantial notational and conceptual gap between the different but equivalent approaches to scalar or tensorial Minkowski functionals in mathematics and in physics, hence making the mathematical measure theoretic method more readily accessible for future application in the physical sciences
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