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1.
Fortschr Neurol Psychiatr ; 91(3): 80-87, 2023 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-35724682

RESUMO

OBJECTIVE: In recent years, studies investigating the use of psilocybin to treat mental disorders have shown promising results. In this context, this online survey investigated attitudes of trained psychiatrists and psychotherapists towards psilocybin and psilocybin-assisted therapies. MATERIALS AND METHODS: A total of 530 valid responses from individuals with suitable job profiles were collected in this online survey. Statistical analysis was used to identify relevant predictors of attitude measures. RESULTS: The opinions of experts in the treatment of mental disorders with psilocybin and psilocybin-assisted therapies varied widely, and the level of knowledge of the participants to some extent was low. A large number of participants considered treatment of mental disorders with psilocybin to be promising and treatment of depression with psilocybin was seen as promising by the majority of the participants. The results of this study suggest that a higher level of knowledge about psilocybin is associated with more optimistic views about its use in a therapeutic setting. Having additional scientific information led in some cases to more optimistic attitudes towards psilocybin and the use of psilocybin in the treatment of mental disorders. CONCLUSION: If the scientific and public discourse on psilocybin continues to grow in the future, changes in the attitudes of psychotherapists and psychiatrists can be expected.


Assuntos
Alucinógenos , Transtornos Mentais , Humanos , Psilocibina/uso terapêutico , Saúde Mental , Alucinógenos/uso terapêutico , Transtornos Mentais/tratamento farmacológico , Transtornos Mentais/psicologia , Atitude
2.
Soft Matter ; 18(33): 6222-6228, 2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-35894155

RESUMO

We study the self-assembly of branching-chain networks and crystals in a binary colloidal system with tunable interactions. The particle positions are extracted from microscopy images and order parameters are extracted by image processing and statistical analysis. With these, we construct phase diagrams with respect to particle density, ratio and interaction. In order to draw a more complete picture, we complement the experiments with computer simulations. We establish a region in the phase diagram, where bead ratios and interactions are symmetric, promoting percolated structures.

3.
Cogn Affect Behav Neurosci ; 21(5): 936-947, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34075542

RESUMO

Despite its relevance for health and education, the neurocognitive mechanism of real-life self-control is largely unknown. While recent research revealed a prominent role of the ventromedial prefrontal cortex in the computation of an integrative value signal, the contribution and relevance of other brain regions for real-life self-control remains unclear. To investigate neural correlates of decisions in line with long-term consequences and to assess the potential of brain decoding methods for the individual prediction of real-life self-control, we combined functional magnetic resonance imaging during preference decision making with ecological momentary assessment of daily self-control in a large community sample (N = 266). Decisions in line with long-term consequences were associated with increased activity in bilateral angular gyrus and precuneus, regions involved in different forms of perspective taking, such as imagining one's own future and the perspective of others. Applying multivariate pattern analysis to the same clusters revealed that individual patterns of activity predicted the probability of real-life self-control. Brain activations are discussed in relation to episodic future thinking and mentalizing as potential mechanisms mediating real-life self-control.


Assuntos
Mapeamento Encefálico , Autocontrole , Encéfalo/diagnóstico por imagem , Tomada de Decisões , Humanos , Imageamento por Ressonância Magnética
4.
Phys Rev Lett ; 127(13): 136102, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34623839

RESUMO

We report real space location of hydrogen in single crystalline Fe/V superstructures. Anisotropic strain is quantified versus hydrogen concentration by using the yield of backscattered primary 2 MeV ^{4}He ions for incidence in different crystallographic directions. From a comparison of ion channeling in combination with ^{1}H(^{15}N,αγ)^{12}C nuclear reaction analysis and Monte Carlo simulations we show that hydrogen is located in octahedral z sites and quantify its vibrational amplitude of 0.2 Å.

5.
Langmuir ; 37(14): 4064-4071, 2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33797254

RESUMO

We study the assembly of magnetite nanoparticles in water-based ferrofluids in wetting layers close to silicon substrates with different functionalization without and with an out-of-plane magnetic field. For particles of nominal sizes 5, 15, and 25 nm, we extract density profiles from neutron reflectivity measurements. We show that self-assembly is only promoted by a magnetic field if a seed layer is formed at the silicon substrate. Such a layer can be formed by chemisorption of activated N-hydroxysuccinimide ester-coated nanoparticles at a (3-aminopropyl)triethoxysilane functionalized surface. Less dense packing is reported for physisorption of the same particles at a piranha-treated (strongly hydrophilic) silicon wafer, and no wetting layer is found for a self-assembled monolayer of octadecyltrichlorosilane (strongly hydrophobic) at the interface. We show that once the seed layer is formed and under an out-of-plane magnetic field further wetting layers assemble. These layers become denser with time, larger magnetic fields, higher particle concentrations, and larger moment of the nanoparticles.

6.
J Pers ; 89(6): 1113-1125, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33866562

RESUMO

OBJECTIVE: Need for Cognition (NFC) refers to a personality trait describing the relatively stable intrinsic motivation of individuals to invest cognitive effort in cognitive endeavors. Higher NFC is associated with a more elaborated, central information processing style and increased recruitment of resources in cognitively demanding situations. To further clarify the association between cognitive resources and NFC, we examined in two studies how NFC relates to executive functions as basic cognitive abilities. METHOD: In Study 1, 189 healthy young adults completed an NFC scale and a battery of six commonly used inhibitory control tasks (Stroop, antisaccade, stop-signal, flanker, shape-matching, word-naming). In Study 2, 102 healthy young adults completed the NFC scale and two tasks for each of the three executive functions inhibitory control (go-nogo, stop-signal), shifting (number-letter, color-shape), and working memory updating (two-back, letter-memory). RESULTS: Using a Bayesian approach to correlation analysis, we found no conclusive evidence that NFC was related to any executive function measure. Instead, we obtained even moderate evidence for the null hypothesis. CONCLUSIONS: Both studies add to more recent findings that shape the understanding of NFC as a trait that is less characterized by increased cognitive control abilities but rather by increased willingness to invest effort and exert self-control via motivational processes.


Assuntos
Função Executiva , Autocontrole , Teorema de Bayes , Cognição , Humanos , Motivação , Adulto Jovem
7.
J Pers ; 89(3): 402-421, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32858777

RESUMO

OBJECTIVE: To test the hypothesis that chronic stress impairs the use of cognitive control for self-control, we examined how chronic stress affects the relation between individual differences in general executive functioning (GEF) and self-control in real-life situations. METHOD: About 338 young adults with varying degrees of chronic stress underwent experience sampling of real-life self-control for 7 days and completed a battery of nine executive function tasks from which a latent variable representing individual differences in GEF was derived. RESULTS: Structural equation models showed that higher levels of chronic stress were associated with stronger desires and a less negative relationship between GEF and desire strength. Chronic stress and GEF did not predict desire enactment in situations where effortful resistance was attempted. CONCLUSIONS: These findings suggest that chronic stress may impair self-control by reducing the use of cognitive control for "early" desire regulation strategies while leaving "late" resistance strategies unaffected. That relationships between executive functioning and real-life self-control can be moderated by third factors such as chronic stress may to some extent explain the common finding of weak or missing associations between laboratory measures of executive functioning and real-life self-control.


Assuntos
Função Executiva , Autocontrole , Avaliação Momentânea Ecológica , Humanos , Individualidade , Adulto Jovem
8.
Psychol Sci ; 31(3): 268-279, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32024421

RESUMO

Deficient self-control leads to shortsighted decisions and incurs severe personal and societal costs. Although neuroimaging has advanced our understanding of neural mechanisms underlying self-control, the ecological validity of laboratory tasks used to assess self-control remains largely unknown. To increase ecological validity and to test a specific hypothesis about the mechanisms underlying real-life self-control, we combined functional MRI during value-based decision-making with smartphone-based assessment of real-life self-control in a large community sample (N = 194). Results showed that an increased propensity to make shortsighted decisions and commit self-control failures, both in the laboratory task as well as during real-life conflicts, was associated with a reduced modulation of neural value signals in the ventromedial prefrontal cortex in response to anticipated long-term consequences. These results constitute the first evidence that neural mechanisms mediating anticipations of future consequences not only account for self-control in laboratory tasks but also predict real-life self-control, thereby bridging the gap between laboratory research and real-life behavior.


Assuntos
Tomada de Decisões/fisiologia , Córtex Pré-Frontal/fisiologia , Autocontrole , Adulto , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Smartphone , Adulto Jovem
9.
Soft Matter ; 16(33): 7676-7684, 2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32804181

RESUMO

We reveal the assembly of magnetite nanoparticles of sizes 5 nm, 15 nm and 25 nm from dilute water-based ferrofluids onto an amorphous magnetic template with out-of-plane anisotropy. From neutron reflectometry experiments we extract density profiles and show that the particles self-assemble into layers at the magnetic surface. The layers are extremely stable against cleaning and rinsing of the substrate. The density of the layers is determined by and increases with the remanent magnetic moment of the particles.

10.
Molecules ; 25(14)2020 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-32664654

RESUMO

We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH2-x) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations and photochromic response of the films were strongly dependent on the deposition pressure. The GdHO films showed a preferential orientation along the [100] direction and exhibited photochromism when synthesized at deposition pressures of up to 5.8 Pa. The photochromic contrast was larger than 20% when the films were deposited below 2.8 Pa with a 0.22 H2/Ar flow ratio. We argue that the relation of preferential orientation and the post deposition oxidation since oxygen concentration is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above were explained by the decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas, followed by a higher oxygen incorporation.

11.
Phys Rev Lett ; 123(1): 016101, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31386422

RESUMO

We report the detection and quantification of nuclear spin incoherent scattering from hydrogen occupying interstitial sites in a thin film of vanadium. The neutron wave field is enhanced in a quantum resonator with magnetically switchable boundaries. Our results provide a pathway for the study of dynamics at surfaces and in ultrathin films using inelastic and/or quasielastic neutron scattering methods.

12.
Langmuir ; 35(11): 3980-3986, 2019 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-30767539

RESUMO

The effect of small quantities of a magnetic polymer nanocomposite (formed by surfactant Pluronic F127 @ Fe3O4 nanoparticles of 10 and 30 nm diameters) on the crystallization behavior of Pluronic F127 micelles solvated by 20% in water was investigated in the vicinity of hydrophilic and hydrophobic interfaces. Introducing magnetic nanoparticle at the core imparts magnetic properties to the polymeric micelle and increases its hydrodynamic diameter. These magnetic polymer nanocomposites act as defects in the pluronic crystal and hinder crystallization in comparison to pure Pluronic F127 micelles' behavior. The magnetic field results in a motion of the magnetic micelles and a microshearing effect. This microshearing assists in self-organization of the crystal. Addition of magnetic micelles formed using 30 nm magnetite particles shows similar crystallization behavior, however, with an overall reduced crystallinity due to their significantly larger size compared to the lattice parameter and the dimension of the interstitial cavity for an fcc structure.

13.
Soft Matter ; 15(3): 371-380, 2019 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-30519692

RESUMO

Entangled polymers are deformed by a strong shear flow. The shape of the polymer, called the form factor, is measured by small angle neutron scattering. However, the real-space molecular structure is not directly available from the reciprocal-space data, due to the phase problem. Instead, the data has to be fitted with a theoretical model of the molecule. We approximate the unknown structure using piecewise straight segments, from which we derive an analytical form factor. We fit it to our data on a semi-dilute entangled polystyrene solution under in situ shear flow. The character of the deformation is shown to lie between that of a single ideal chain (viscous) and a cross-linked network (elastic rubber). Furthermore, we use the fitted structure to estimate the mechanical stress, and find a fairly good agreement with rheology literature.

14.
Cogn Affect Behav Neurosci ; 18(4): 622-637, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29654477

RESUMO

Despite their immense relevance, the neurocognitive mechanisms underlying real-life self-control failures (SCFs) are insufficiently understood. Whereas previous studies have shown that SCFs were associated with decreased activity in the right inferior frontal gyrus (rIFG; a region involved in cognitive control), here we consider the possibility that the reduced implementation of cognitive control in individuals with low self-control may be due to impaired performance monitoring. Following a brain-as-predictor approach, we combined experience sampling of daily SCFs with functional magnetic resonance imaging (fMRI) in a Stroop task. In our sample of 118 participants, proneness to SCF was reliably predicted by low error-related activation of a performance-monitoring network (comprising anterior mid-cingulate cortex, presupplementary motor area, and anterior insula), low posterror rIFG activation, and reduced posterror slowing. Remarkably, these neural and behavioral measures predicted variability in SCFs beyond what was predicted by self-reported trait self-control. These results suggest that real-life SCFs may result from deficient performance monitoring, leading to reduced recruitment of cognitive control after responses that conflict with superordinate goals.


Assuntos
Encéfalo/fisiologia , Autocontrole , Adulto , Atenção/fisiologia , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Função Executiva/fisiologia , Feminino , Humanos , Individualidade , Imageamento por Ressonância Magnética , Masculino , Teste de Stroop , Adulto Jovem
15.
Eur Phys J E Soft Matter ; 41(1): 9, 2018 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-29353322

RESUMO

Colloidal systems offer unique opportunities for the study of phase formation and structure since their characteristic length scales are accessible to visible light. As a model system the two-dimensional assembly of colloidal magnetic and non-magnetic particles dispersed in a ferrofluid (FF) matrix is studied by transmission optical microscopy. We present a method to statistically evaluate images with thousands of particles and map phases by extraction of local variables. Different lattice structures and long-range connected branching chains are observed, when tuning the effective magnetic interaction and varying particle ratios.

16.
J Chem Phys ; 149(7): 074901, 2018 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-30134722

RESUMO

The non-linear response of entangled polymers to shear flow is complicated. Its current understanding is framed mainly as a rheological description in terms of the complex viscosity. However, the full picture requires an assessment of the dynamical structure of individual polymer chains which give rise to the macroscopic observables. Here we shed new light on this problem, using a computer simulation based on a blob model, extended to describe shear flow in polymer melts and semi-dilute solutions. We examine the diffusion and the intermediate scattering spectra during a steady shear flow. The relaxation dynamics are found to speed up along the flow direction, but slow down along the shear gradient direction. The third axis, vorticity, shows a slowdown at the short scale of a tube, but reaches a net speedup at the large scale of the chain radius of gyration.

17.
Langmuir ; 32(35): 9091-6, 2016 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-27516185

RESUMO

We apply specular and off-specular neutron reflection at the hydrophobic silicon/water interface to check for evidence of nanoscopic air bubbles whose presence is claimed after an ad hoc procedure of solvent exchange. Nanobubbles and/or a depletion layer at the hydrophobic/water interface have long been discussed and generated a plethora of controversial scientific results. By combining neutron reflectometry (NR), off-specular reflectometry (OSS), and grazing incidence small angle neutron scattering (GISANS), we studied the interface between hydrophobized silicon and heavy water before and after saturation with nitrogen gas. Our specular reflectometry results can be interpreted by assuming a submolecular sized depletion layer and the off-specular measurements show no change with nitrogen super saturated water. This picture is consistent with the assumption that, following the solvent exchange, no additional nanobubbles are introduced at significant concentrations (if present at all). Furthermore, we discuss the results in terms of the maximum surface coverage of nanobubbles that could be present on the hydrophobic surface compatibly with the sensitivity limit of these techniques.

18.
Psychol Res ; 80(6): 944-951, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26403462

RESUMO

Although cognitive control is commonly identified as the basis of self-controlled behavior, correlations found between trait self-control and laboratory measures of cognitive control such as Stroop interference are typically low. Based on the notion that self-control requires the ability to refrain from rewarded behaviors, and inspired by the recent finding that Stroop interference is modulated by reward associations, we propose the idea that the modulation of interference by reward associations (MIRA) is a cognitive marker of trait self-control. Two independent samples of participants completed (1) a modified Stroop task designed to assess MIRA and (2) two common measures of trait self-control: the Brief Self-Control Scale (BSCS) and the Barratt Impulsiveness Scale (BIS-11). MIRA was strongly correlated with the BSCS and moderately correlated with two of the three subscales of the BIS-11. MIRA thus appears to reflect a cognitive endophenotype of individual differences in self-control, and perhaps of related mental disorders.


Assuntos
Comportamento Impulsivo , Recompensa , Autocontrole , Análise e Desempenho de Tarefas , Adolescente , Adulto , Feminino , Humanos , Individualidade , Masculino , Autorrelato , Teste de Stroop
19.
Soft Matter ; 11(23): 4695-704, 2015 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-25971712

RESUMO

Neutron reflectometry was used to study the assembly of magnetite nanoparticles in a water-based ferrofluid close to a silicon surface. Under three conditions, static, under shear and with a magnetic field, the depth profile is extracted. The particles have an average diameter of 11 nm and a volume density of 5% in a D2O-H2O mixture. They are surrounded by a 4 nm thick bilayer of carboxylic acid for steric repulsion. The reflectivity data were fitted to a model using a least square routine based on the Parratt formalism. From the scattering length density depth profiles the following behavior is concluded: the fits indicate that excess carboxylic acid covers the silicon surface and almost eliminates the water in the densely packed wetting layer that forms close to the silicon surface. Under constant shear the wetting layer persists but a depletion layer forms between the wetting layer and the moving ferrofluid. Once the flow is stopped, the wetting layer becomes more pronounced with dense packing and is accompanied by a looser packed second layer. In the case of an applied magnetic field the prolate particles experience a torque and align with their long axes along the silicon surface which leads to a higher particle density.

20.
Phys Rev Lett ; 113(4): 046103, 2014 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-25105636

RESUMO

We investigate the effect of finite size on phase boundaries of hydride formation in ultrathin metallic films, using Fe/V(001) superlattices as a model system. The critical temperature is determined to scale linearly with the inverse thickness of the V layers. The decrease of the ordering temperature with decreasing layer thickness arises from the missing H neighbors at the interfaces, analogous to observed finite-size effects in magnetic layers and nanosized ice crystals.

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