ABSTRACT
Much like passive materials, active systems can be affected by the presence of imperfections in their microscopic order, called defects, that influence macroscopic properties. This suggests the possibility to steer collective patterns by introducing and controlling defects in an active system. Here we show that a self-assembled, passive nematic is ideally suited to control the pattern formation process of an active fluid. To this end, we force microtubules to glide inside a passive nematic material made from actin filaments. The actin nematic features self-assembled half-integer defects that steer the active microtubules and lead to the formation of macroscopic polar patterns. Moreover, by confining the nematic in circular geometries, chiral loops form. We find that the exact positioning of nematic defects in the passive material deterministically controls the formation and the polarity of the active flow, opening the possibility of efficiently shaping an active material using passive defects.
ABSTRACT
Topological defects play a central role in the formation and organization of various biological systems. Historically, such nonequilibrium defects have been mainly studied in the context of homogeneous active nematics. Phase-separated systems, in turn, are known to form dense and dynamic nematic bands, but typically lack topological defects. In this paper, we use agent-based simulations of weakly aligning, self-propelled polymers and demonstrate that contrary to the existing paradigm phase-separated active nematics form -1/2 defects. Moreover, these defects, emerging due to interactions among dense nematic bands, constitute a novel second-order collective state. We investigate the morphology of defects in detail and find that their cores correspond to a strong increase in density, associated with a condensation of nematic fluxes. Unlike their analogs in homogeneous systems, such condensed defects form and decay in a different way and do not involve positively charged partners. We additionally observe and characterize lateral arc-like structures that separate from a band's bulk and move in transverse direction. We show that the key control parameters defining the route from stable bands to the coexistence of dynamic lanes and defects are the total density of particles and their path persistence length. We introduce a hydrodynamic theory that qualitatively recapitulates all the main features of the agent-based model, and use it to show that the emergence of both defects and arcs can be attributed to the same anisotropic active fluxes. Finally, we present a way to artificially engineer and position defects, and speculate about experimental verification of the provided model.
ABSTRACT
There is a need for interventions supporting patients with mental health conditions in coping with stigma and discrimination. A psycho-educational group therapy module to promote stigma coping and empowerment (STEM) was developed and tested for efficacy in patients with schizophrenia or depression. 30 clinical centers participated in a cluster-randomized clinical trial, representing a broad spectrum of mental health care settings: in-patient (acute treatment, rehabilitation), out-patient, and day-hospitals. As randomized, patients in the intervention group clusters/centers received an illness-specific eight sessions standard psychoeducational group therapy plus three specific sessions on stigma coping and empowerment ('STEM'). In the control group clusters the same standard psychoeducational group therapy was extended to 11 sessions followed by one booster session in both conditions. In total, N = 462 patients were included in the analysis (N = 117 with schizophrenia spectrum disorders, ICD-10 F2x; N = 345 with depression, ICD-10 F31.3-F31.5, F32-F34, and F43.2). Clinical and stigma-related measures were assessed before and directly after treatment, as well as after 6 weeks, 6 months, and 12 months (M12). Primary outcome was improvement in quality of life (QoL) assessed with the WHO-QOL-BREF between pre-assessment and M12 analyzed by mixed models and adjusted for pre-treatment differences. Overall, QoL and secondary outcome measures (symptoms, functioning, compliance, internalized stigma, self-esteem, empowerment) improved significantly, but there was no significant difference between intervention and control group. The short STEM module has proven its practicability as an add-on in different settings in routine mental health care. The overall increase in empowerment in both, schizophrenia and depression, indicates patients' treatment benefit. However, factors contributing to improvement need to be explored.The study has been registered in the following trial registers. ClinicalTrials.gov: https://register.clinicaltrials.gov/ Registration number: NCT01655368. DRKS: https://www.drks.de/drks_web/ Registration number: DRKS00004217.
Subject(s)
Adaptation, Psychological , Depressive Disorder/rehabilitation , Empowerment , Mentally Ill Persons/psychology , Outcome Assessment, Health Care , Psychotherapy, Group , Schizophrenia/rehabilitation , Social Stigma , Adult , Female , Humans , Male , Middle Aged , Patient Education as Topic , Quality of Life , Self ConceptABSTRACT
Cooperative π-π interactions and H-bonding are frequently exploited in supramolecular polymerization; however, close scrutiny of their mutual interplay has been largely unexplored. Herein, we compare the self-assembly behavior of a series of C2 - and C3 -symmetrical oligophenyleneethynylenes differing in their amide topology (N- or C-centered). This subtle structural modification brings about drastic changes in their photophysical and supramolecular properties, highlighting the reciprocal impact of H-bonding vs. preorganization on the evolution and final outcome of supramolecular systems.
ABSTRACT
Drug-induced agranulocytosis is a rare but life-threatening side effect which is possibly based on immunogenetic mechanisms. Some studies regarding agranulocytosis induced by the atypical antipsychotic clozapine dealing with HLA subtyping and enzyme polymorphisms have been performed to elucidate its genetic background. To further screen possibly genetically based pathways of developing agranulocytosis, we assessed clinically relevant polymorphisms of immunoglobulin G or Fcgamma receptors in patients with clozapine-induced (n = 48), ticlopidine-induced (n = 11), thyroid inhibitors-induced agranulocytosis (n = 8), and controls (n = 75). We found significant age-related effects in each of the drug-induced agranulocytoses but no further associations that underline an effect of polymorphisms in FcgammaRIIa, FcgammaRIIIa, and FcgammaRIIIb genes on drug-induced agranulocytosis. Thus, Fcgamma receptors may not serve as a genetic marker to identify patients at risk for this life-threatening side effect.
Subject(s)
Agranulocytosis/chemically induced , Agranulocytosis/genetics , Receptors, IgG/genetics , Receptors, IgG/metabolism , Adult , Agranulocytosis/blood , Antipsychotic Agents/adverse effects , Antithyroid Agents/adverse effects , Clozapine/adverse effects , DNA/genetics , Female , Fibrinolytic Agents/adverse effects , Genotype , Humans , Leukocyte Count , Male , Middle Aged , Ticlopidine/adverse effectsABSTRACT
A lot of progress has been made in the treatment of schizophrenia against hallucinations and delusions. However, Schizophrenia still remains a highly disabling disease causing tremendous deficits in social- and vocational functioning. Cognitive deficits are known since the early 90's as a further core feature of schizophrenia, and it has been shown that social- and vocational dysfunctions are closely related to neurocognitive deficits. Whether those findings bear a potential for therapeutic implications still needs to be shown. In this overview therapeutic interventions with respect to cognitive deficits and their effectiveness and their role for vocational rehabilitation will be summarized.