185 research outputs found
The Study of Personality Architecture and Dynamics (SPeADy): A Longitudinal and Extended Twin Family Study
Kandler C, Penner A, Richter J, Zapko-Willmes A. The Study of Personality Architecture and Dynamics (SPeADy): A Longitudinal and Extended Twin Family Study. Twin Research and Human Genetics. 2019;22(6):1-6.AbstractThe Study of Personality Architecture and Dynamics (SPeADy) is a German research project that aims to investigate the sources of interindividual differences in intraindividual personality development. The main focus lies in the dynamic interplay between more stable core characteristics and more environmentally malleable surface characteristics, as well as between personality and life experiences over time. SPeADy includes a twin family study encompassing data from 1962 individuals (age: 14–94) of 682 families, including 570 complete twin pairs (plus 1 triplet set), 327 parents, 236 spouses and 145 children of twins. Data collection started in 2016 and data from the first wave are currently obtainable as open source. Available data comprise a broad range of personality variables, such as personality trait constructs, motives, interests, values, moral foundations, religiosity and self-related concepts. For the currently ongoing second wave of data collection, we added retrospective reports on major life events. Special features of this genetically informative study are the extended twin family data and its longitudinal design. Three assessment waves in 2 years’ intervals are planned until 2022. In this article, we briefly describe the design and contents of the SPeADy twin family study as well as some recent findings, future plans and open science issues.</jats:p
Dystonia and Paroxysmal Dyskinesias: Under-Recognized Movement Disorders in Domestic Animals? A Comparison with Human Dystonia/Paroxysmal Dyskinesias
Dystonia is defined as a neurological syndrome characterized by involuntary sustained or intermittent muscle contractions causing twisting, often repetitive movements, and postures. Paroxysmal dyskinesias are episodic movement disorders encompassing dystonia, chorea, athetosis, and ballism in conscious individuals. Several decades of research have enhanced the understanding of the etiology of human dystonia and dyskinesias that are associated with dystonia, but the pathophysiology remains largely unknown. The spontaneous occurrence of hereditary dystonia and paroxysmal dyskinesia is well documented in rodents used as animal models in basic dystonia research. Several hyperkinetic movement disorders, described in dogs, horses and cattle, show similarities to these human movement disorders. Although dystonia is regarded as the third most common movement disorder in humans, it is often misdiagnosed because of the heterogeneity of etiology and clinical presentation. Since these conditions are poorly known in veterinary practice, their prevalence may be underestimated in veterinary medicine. In order to attract attention to these movement disorders, i.e., dystonia and paroxysmal dyskinesias associated with dystonia, and to enhance interest in translational research, this review gives a brief overview of the current literature regarding dystonia/paroxysmal dyskinesia in humans and summarizes similar hereditary movement disorders reported in domestic animals
Deep brain stimulation for movement disorder treatment: Exploring frequency-dependent efficacy in a computational network model
A large scale computational model of the basal ganglia (BG) network is
proposed to describes movement disorder including deep brain stimulation (DBS).
The model of this complex network considers four areas of the basal ganglia
network: the subthalamic nucleus (STN) as target area of DBS, globus pallidus,
both pars externa and pars interna (GPe-GPi), and the thalamus (THA).
Parkinsonian conditions are simulated by assuming reduced dopaminergic input
and corresponding pronounced inhibitory or disinhibited projections to GPe and
GPi. Macroscopic quantities can be derived which correlate closely to thalamic
responses and hence motor programme fidelity. It can be demonstrated that
depending on different levels of striatal projections to the GPe and GPi, the
dynamics of these macroscopic quantities switch from normal conditions to
parkinsonian. Simulating DBS on the STN affects the dynamics of the entire
network, increasing the thalamic activity to levels close to normal, while
differing from both normal and parkinsonian dynamics. Using the mentioned
macroscopic quantities, the model proposes optimal DBS frequency ranges above
130 Hz.Comment: 40 pages, 16 figure
On-surface synthesis on a bulk insulator surface
On-surface synthesis has rapidly emerged as a most promising approach to prepare functional molecular structures directly on a support surface. Compared to solution synthesis, performing chemical reactions on a surface offers several exciting new options: due to the absence of a solvent, reactions can be envisioned that are otherwise not feasible due to the insolubility of the reaction product. Perhaps even more important, the confinement to a two-dimensional surface might enable reaction pathways that are not accessible otherwise. Consequently, on-surface synthesis has attracted great attention in the last decade, with an impressive number of classical reactions transferred to a surface as well as new reactions demonstrated that have no classical analogue.
So far, the majority of the work has been carried out on conducting surfaces. However, when aiming for electronic decoupling of the resulting structures, e.g. for the use in future molecular electronic devices, non-conducting surfaces are highly desired. Here, we review the current status of on-surface reactions demonstrated on the (10.4) surface of the bulk insulator calcite. Besides thermally induced C–C coupling of halogen-substituted aryls, photochemically induced [2  +  2] cycloaddition has been proven possible on this surface. Moreover, experimental evidence exists for coupling of terminal alkynes as well as diacetylene polymerization. While imaging of the resulting structures with dynamic atomic force microscopy provides a direct means of reaction verification, the detailed reaction pathway often remains unclear. Especially in cases where the presence of metal atoms is known to catalyze the corresponding solution chemistry reaction (e.g. in the case of the Ullmann reaction), disclosing the precise reaction pathway is of importance to understand and generalize on-surface reactivity on a bulk insulator surface. To this end, density-functional theory calculations have proven to provide atomic-scale insights that have greatly contributed to unravelling the details of on-surface synthesis on a bulk insulator surface
Ein Ordnungsrahmen fĂĽr Social Networking Services
Der große Erfolg vieler Internet-Plattformen zum Social Networking, wie facebook.com oder myspace.com zieht zunehmend auch die Aufmerksamkeit großer Unternehmen auf sich, die mit ähnlichen Werkzeugen ihr internes Wissens- und Innovationsmanagement verbessern möchten. Im Gegensatz zu anderer Social Software wie Wikis oder Weblogs, die sich in der Regel leicht für den Einsatz innerhalb des Firmen-Intranets adaptieren lassen, ist dies für Social Networking Services (SNS) jedoch schwieriger. Zum einen existieren kaum Open-Source-Anwendungen, die ohne großen Aufwand implementierbar sind. Zum anderen unterscheiden sich die Lösungen von SNS-Anbietern enorm, was es den Unternehmen schwer macht, eine geeignete Lösung auszuwählen. Eine Hilfestellung soll der im vorliegenden Beitrag vorgestellte Ordnungsrahmen für SNS bieten. Entlang von acht Dimensionen ermöglicht er den Vergleich und die Einordnung verschiedener Dienste
Homocoupling of terminal alkynes on calcite (10.4)
Richter A, Vilas-Varela M, Peña D, Bechstein R, Kühnle A. Homocoupling of terminal alkynes on calcite (10.4). Surface Science. 2018;678:106-111
Achieving high effective Q-factors in ultra-high vacuum dynamic force microscopy
Lübbe J, Tröger L, Torbrügge S, et al. Achieving high effective Q-factors in ultra-high vacuum dynamic force microscopy. Measurement Science and Technology. 2010;21(12): 125501.The effective Q-factor of the cantilever is one of the most important figures-of-merit for a non-contact atomic force microscope (NC-AFM) operated in ultra-high vacuum (UHV). We provide a comprehensive discussion of all effects influencing the Q-factor and compare measured Q-factors to results from simulations based on the dimensions of the cantilevers. We introduce a methodology to investigate in detail how the effective Q-factor depends on the fixation technique of the cantilever. Fixation loss is identified as a most important contribution in addition to the hitherto discussed effects and we describe a strategy for avoiding fixation loss and obtaining high effective Q-factors in the force microscope. We demonstrate for room temperature operation, that an optimum fixation yields an effective Q-factor for the NC-AFM measurement in UHV that is equal to the intrinsic value of the cantilever
Diacetylene polymerization on a bulk insulator surface
Richter A, Haapasilta V, Venturini C, et al. Diacetylene polymerization on a bulk insulator surface. Physical Chemistry Chemical Physics. 2017;19(23):15172-15176.Molecular electronics has great potential to surpass known limitations in conventional silicon-based technologies. The development of molecular electronics devices requires reliable strategies for connecting functional molecules by wire-like structures. To this end, diacetylene polymerization has been discussed as a very promising approach for contacting single molecules with a conductive polymer chain. A major challenge for future device fabrication is transferring this method to bulk insulator surfaces, which are mandatory to decouple the electronic structure of the functional molecules from the support surface. Here, we provide experimental evidence for diacetylene polymerization of 3,30-(1,3-butadiyne-1,4-diyl) bisbenzoic acid precursors on the (10.4) surface of calcite, a bulk insulator with a band gap of around 6 eV. When deposited on the surface held at room temperature, ordered islands with a (1 x 3) superstructure are observed using dynamic atomic force microscopy. A distinct change is revealed upon heating the substrate to 485 K. After heating, molecular stripes with a characteristic inner structure are formed that excellently match the expected diacetylene polymer chains in appearance and repeat distance. The corresponding density functional theory computations reveal molecular-level bonding patterns of both the (1 x 3) superstructure and the formed striped structure, confirming the assignment of on-surface diacetylene polymerization. Transferring the concept of using diacetylene polymerization for creating conductive connections to bulk insulator surfaces paves the way towards application-relevant systems for future molecular electronic devices
Generic nature of long-range repulsion mechanism on a bulk insulator?
Neff JL, Richter A, Söngen H, et al. Generic nature of long-range repulsion mechanism on a bulk insulator? Faraday Discussions. 2017;204:419-428
Growth kinetics of racemic heptahelicene-2-carboxylic acid nanowires on calcite (104)
Einax M, Richter T, Nimmrich M, et al. Growth kinetics of racemic heptahelicene-2-carboxylic acid nanowires on calcite (104). Journal of Chemical Physics. 2016;145(13):134702.Molecular self-assembly of racemic heptahelicene-2-carboxylic acid on a dielectric substrate at room temperature can be used to generate wire-like organic nanostructures consisting of single and double molecular rows. By means of non-contact atomic force microscopy, we investigate the growth of the wire-like pattern after deposition by experimental and theoretical means. From analyzing the time dependence of the mean row length, two distinct regimes were found. At the early post-deposition stage, the mean length grows in time. Subsequently, a crossover to a second regime is observed, where the mean row length remains nearly constant. We explain these findings by a mean-field rate equation approach providing a comprehensive picture of the growth kinetics. As a result, we demonstrate that the crossover between the two distinct regimes is accomplished by vanishing of the homochiral single rows. At later stages only heterochiral double row structures remain. Published by AIP Publishing
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