Structural Characterization of LaSrCoO Thin Films Grown on (100)-, (110)-, and (111)-Oriented LaSrGaMgO.

In this study, a detailed structural characterization of epitaxial La0.6Sr0.4CoO3-δ (LSC) films grown in (100), (110), and (111) orientations was conducted.

Spontaneous emergence of groups and signaling diversity in dynamic networks.

We study the coevolution of network structure and signaling behavior. We model agents who can preferentially associate with others in a dynamic network while they also learn to play a simple sender-receiver game. We have four major findings.

Crystal-Orientation-Dependent Oxygen Exchange Kinetics on Mixed Conducting Thin-Film Surfaces Investigated by Studies.

The oxygen exchange kinetics and the surface chemistry of epitaxially grown, dense LaSrCoO (LSC) thin films in three different orientations, (001), (110), and (111), were investigated by means of impedance spectroscopy during pulsed laser deposition (i-PLD) and near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS). i-PLD measurements showed that pristine LSC surfaces exhibit very fast surface exchange kinetics but revealed no significant differences between the specific orientations. However, as soon as the surfaces were in contact with acidic, gaseous impurities, such as S-containing compounds in nominally pure measurement atmospheres, NAP-XPS measurements revealed that the (001) orientation is substantially more susceptible to the formation of sulfate adsorbates and a concomitant performance decrease.

Improving and degrading the oxygen exchange kinetics of LaSrCoO by Sr decoration.

Minimizing the overpotential at the air electrode of solid oxide fuel cells (SOFC) is one of the key challenges regarding a broad applicability of this technology. Next to novel materials and geometry optimization, surface modification is a promising and flexible method to alter the oxygen exchange kinetics at SOFC cathode surfaces. Despite extensive research, the mechanism behind the effect of surface decorations is still under debate.

Surface Decorations on Mixed Ionic and Electronic Conductors: Effects on Surface Potential, Defects, and the Oxygen Exchange Kinetics.

The oxygen exchange kinetics of epitaxial PrCeO electrodes was modified by decoration with submonolayer amounts of different basic (SrO, CaO) and acidic (SnO, TiO) binary oxides. The oxygen exchange reaction (OER) rate and the total conductivity were measured by PLD impedance spectroscopy (-PLD), which allows to directly track changes of electrochemical properties after each deposited pulse of surface decoration. The surface chemistry of the electrodes was investigated by near-ambient pressure XPS measurements (NAP-XPS) at elevated temperatures and by low-energy ion scattering (LEIS).

electrochemical observation of anisotropic lattice contraction of LaSrFeO electrodes during pulsed laser deposition.

LaSrFeO (LSF) electrodes were grown on different electrolyte substrates by pulsed laser deposition (PLD) and their oxygen exchange reaction (OER) resistance was tracked in real-time by PLD impedance spectroscopy (i-PLD) inside the PLD chamber. This enables measurements on pristine surfaces free from any contaminations and the direct observation of thickness dependent properties. As substrates, yttria-stabilized zirconia single crystals (YSZ) were used for polycrystalline LSF growth and LaSrGaMgO (LSGM) single crystals or YSZ single crystals with a 5 nm buffer-layer of GdCeO for epitaxial LSF film growth.

techniques reveal the true capabilities of SOFC cathode materials and their sudden degradation due to omnipresent sulfur trace impurities.

In this study, five different mixed conducting cathode materials were grown as dense thin films by pulsed laser deposition (PLD) and characterized impedance spectroscopy directly after growth inside the PLD chamber (i-PLD). This technique enables quantification of the oxygen reduction kinetics on pristine and contaminant-free mixed conducting surfaces. The measurements reveal excellent catalytic performance of all pristine materials with polarization resistances being up to two orders of magnitude lower than those previously reported in the literature.

Performance modulation through selective, homogenous surface doping of lanthanum strontium ferrite electrodes revealed by PLD impedance measurements.

Accelerating the oxygen reduction kinetics of solid oxide fuel cell (SOFC) cathodes is crucial to improve their efficiency and thus to provide the basis for an economically feasible application of intermediate temperature SOFCs. In this work, minor amounts of Pt were doped into lanthanum strontium ferrite (LSF) thin film electrodes to modulate the material's oxygen exchange performance. Surprisingly, Pt was found to be incorporated on the B-site of the perovskite electrode as non metallic Pt.

Investigating oxygen reduction pathways on pristine SOFC cathode surfaces by PLD impedance spectroscopy.

The oxygen exchange reaction mechanism on truly pristine surfaces of SOFC cathode materials (LaSrCoO = LSC, LaSrFeO = LSF, (LaSr)PtFeO = Pt:LSF, SrTiFeO = STF, PrCeO = PCO and LaSrMnO = LSM) was investigated employing impedance spectroscopy during pulsed laser deposition (i-PLD) over a wide temperature and (O) range. Besides demonstrating the often astonishing catalytic capabilities of the materials, it is possible to discuss the oxygen exchange reaction mechanism based on experiments on clean surfaces unaltered by external degradation processes. All investigated materials with at least moderate ionic conductivity ( all except LSM) exhibit polarization resistances with very similar (O)- and -dependences, mostly differing only in absolute value.

Quantifying collective intelligence in human groups.

Collective intelligence (CI) is critical to solving many scientific, business, and other problems, but groups often fail to achieve it. Here, we analyze data on group performance from 22 studies, including 5,279 individuals in 1,356 groups. Our results support the conclusion that a robust CI factor characterizes a group's ability to work together across a diverse set of tasks.

Avoiding the bullies: The resilience of cooperation among unequals.

Can egalitarian norms or conventions survive the presence of dominant individuals who are ensured of victory in conflicts? We investigate the interaction of power asymmetry and partner choice in games of conflict over a contested resource. Previous models of cooperation do not include both power inequality and partner choice. Furthermore, models that do include power inequalities assume a static game where a bully's advantage does not change.

Spite is contagious in dynamic networks.

Spite, costly behavior that harms others, presents an evolutionary puzzle: given that both the actor and recipient do worse, how could it emerge? We show that dynamically evolving interaction networks provide a novel explanation for the evolution of costly harm. Previous work has shown that anti-correlated interaction (e.g.

Quantifying reputation and success in art.

In areas of human activity where performance is difficult to quantify in an objective fashion, reputation and networks of influence play a key role in determining access to resources and rewards. To understand the role of these factors, we reconstructed the exhibition history of half a million artists, mapping out the coexhibition network that captures the movement of art between institutions. Centrality within this network captured institutional prestige, allowing us to explore the career trajectory of individual artists in terms of access to coveted institutions.

Conflict and convention in dynamic networks.

An important way to resolve games of conflict (snowdrift, hawk-dove, chicken) involves adopting a convention: a correlated equilibrium that avoids any conflict between aggressive strategies. Dynamic networks allow individuals to resolve conflict via their network connections rather than changing their strategy. Exploring how behavioural strategies coevolve with social networks reveals new dynamics that can help explain the origins and robustness of conventions.

N- and S-donor leaving groups in triazole-based ruthena(ii)cycles: potent anticancer activity, selective activation, and mode of action studies.

A series of 11 novel ruthenium(ii) arene complexes [Ru(p-cym)(trzC^N)L]NO3 based on the cycloruthenated 1,2,3-triazole scaffold (trzC^N) bearing different N- or S-donor leaving groups (L) were prepared. These complexes exhibited strongly diverging pH-dependent stability profiles, but consistently exerted antiproliferative effects in the low micromolar range in three cancer cell lines (A549, SW480, CH1/PA-1). The interaction with biomolecules was correlated to dissociation of the monodentate leaving group.

Product diffusion through on-demand information-seeking behaviour.

Most models of product adoption predict S-shaped adoption curves. Here we report results from two country-scale experiments in which we find adoption curves. We show evidence that the observed linear pattern is the result of active information-seeking behaviour: individuals actively pulling information from several central sources facilitated by modern Internet searches.

Introducing the 4-Phenyl-1,2,3-Triazole Moiety as a Versatile Scaffold for the Development of Cytotoxic Ruthenium(II) and Osmium(II) Arene Cyclometalates.

Herein we report the synthesis, anticancer potency in vitro, biomolecule interaction, and preliminary mode of action studies of a series of cyclometalated 1,2,3-triazole-derived ruthenium(II) (2a-e) and osmium(II) (3a-e) organometallics of the general form [(η-p-cym)RuCl(κ-C^N-L)] with varying substituents in postion 1 of the 1,2,3-triazole moiety. These cyclometalates were characterized by standard analytical methods and their structures unambiguously assigned by single crystal X-ray crystallography. The anticancer activity of these novel compounds was tested in the human tumor cell lines A549 (non-small cell lung cancer), SW480 (colon adenocarcinoma), and CH1/PA-1 (ovarian teratocarcinoma), and preliminary structure-activity relationships were derived from the obtained data sets.

Looking Across and Looking Beyond the Knowledge Frontier: Intellectual Distance, Novelty, and Resource Allocation in Science.

Selecting among alternative projects is a core management task in all innovating organizations. In this paper, we focus on the evaluation of frontier scientific research projects. We argue that the "intellectual distance" between the knowledge embodied in research proposals and an evaluator's own expertise systematically relates to the evaluations given.