Performance pay, group selection and group performance

Within a laboratory experiment we investigate a principal-agent game in which agents may, first, self-select into a group task (GT) or an individual task (IT) and, second, choose work effort. In their choices of task and effort the agents have to consider pay contracts for both tasks as offered by the principal. The rational solution of the game implies that contract design may not induce agents to select GT and provide positive effort in GT. Furthermore it predicts equal behavior of agents with different productivities. In contrast, considerations of trust, reciprocity and cooperation - the social-emotional model of behavior - suggest that contract design can influence the agents' willingness to join groups and provide effort. We analyze the data by applying a two-step regression model (multinomial logit and tobit) and find that counter to the rational solution, contract design does influence both, task selection and effort choice. The principal can increase participation in work groups and can positively influence group performance. Larger payment increases the share of socially motivated agents in work groups. The selection effect is larger than the motivation effect

Metabolic View on Human Healthspan: A Lipidome-Wide Association Study.

As ageing is a major risk factor for the development of non-communicable diseases, extending healthspan has become a medical and societal necessity. Precise lipid phenotyping that captures metabolic individuality could support healthspan extension strategies. This study applied 'omic-scale lipid profiling to characterise sex-specific age-related differences in the serum lipidome composition of healthy humans. A subset of the COmPLETE-Health study, composed of 73 young (25.2 ± 2.6 years, 43% female) and 77 aged (73.5 ± 2.3 years, 48% female) clinically healthy individuals, was investigated, using an untargeted liquid chromatography high-resolution mass spectrometry approach. Compared to their younger counterparts, aged females and males exhibited significant higher levels in 138 and 107 lipid species representing 15 and 13 distinct subclasses, respectively. Percentage of difference ranged from 5.8% to 61.7% (females) and from 5.3% to 46.0% (males), with sphingolipid and glycerophophospholipid species displaying the greatest amplitudes. Remarkably, specific sphingolipid and glycerophospholipid species, previously described as cardiometabolically favourable, were found elevated in aged individuals. Furthermore, specific ether-glycerophospholipid and lyso-glycerophosphocholine species displayed higher levels in aged females only, revealing a more favourable lipidome evolution in females. Altogether, age determined the circulating lipidome composition, while lipid species analysis revealed additional findings that were not observed at the subclass level

Performance Pay, Group Selection and Group Performance

Within a laboratory experiment we investigate a principal-agent game in which agents may, first, self-select into a group task (GT) or an individual task (IT) and, second, choose work effort. In their choices of task and effort the agents have to consider pay contracts for both tasks as offered by the principal. The rational solution of the game implies that contract design may not induce agents to select GT and provide positive effort in GT. Furthermore it predicts equal behavior of agents with different productivities. In contrast, considerations of trust, reciprocity and cooperation – the social-emotional model of behavior – suggest that contract design can influence the agents ’ willingness to join groups and provide effort. We analyze the data by applying a two-step regression model (multinomial logit and tobit) and find that counter to the rational solution, contract design does influence both, task selection and effort choice. The principal can increase participation in work groups and can positively influence group performance. Larger payment increases the share of socially motivated agents in work groups. The selection effect is larger than the motivation effect

Investigation and comparison of resin materials in transparent DLP-printing for application in cell culture and organs-on-a-chip

Organs-on-a-Chip (OOCs) have recently led to major discoveries and a better understanding of 3D cell organization, cell–cell interactions and tissue response to drugs and biological cues. However, their complexity and variability are still limited by the available fabrication technology. Transparent, cytocompatible and high-resolution 3D-printing could overcome these limitations, offering a flexible and low-cost alternative to soft lithography. Many advances have been made in stereolithography printing regarding resin formulation and the general printing process, but a systematic analysis of the printing process steps, employed resins and post-treatment procedures with a strong focus on the requirements in OOCs is missing. To fill this gap, this work provides an in-depth analysis of three different resin systems in comparison to polystyrene (PS) and poly(dimethylsiloxane) (PDMS), which can be considered the gold-standards in cell culture and microfluidics. The resins were characterized with respect to transparency, cytocompatibility and print resolution. These properties are not only governed by the resin composition, but additionally by the post-treatment procedure. The investigation of the mechanical (elastic modulus ∼2.2 GPa) and wetting properties (∼60° native / 20° plasma treated) showed a behavior very similar to PS. In addition, the absorbance of small molecules was two orders of magnitude lower in the applied resins (diffusion constant ∼0.01 μm2 s−1) than for PDMS (2.5 μm2 s−1), demonstrating the intrinsic suitability of these materials for OOCs. Raman spectroscopy and UV/VIS spectrophotometry revealed that post-treatment increased monomer conversion up to 2 times and removed photo initiator residues, leading to an increased transparency of up to 50 and up to 10-times higher cell viability. High magnification fluorescence imaging of HUVECs and L929 cells cultivated on printed dishes shows the high optical qualities of prints fabricated by the Digital Light Processing (DLP) printer. Finally, components of microfluidic chips such as high-aspect ratio pillars and holes with a diameter of 50 μm were printed. Concluding, the suitability of DLP-printing for OOCs was demonstrated by filling a printed chip with a cell–hydrogel mixture using a microvalve bioprinter, followed by the successful cultivation under perfusion. Our results highlight that DLP-printing has matured into a robust fabrication technology ready for application in extensive and versatile OOC research