Integrating biological vasculature into a multi-organ-chip microsystem

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A chip-based system mimicking the transport function of the human cardiovascular system has been established at minute but standardized microsystem scale. A peristaltic on-chip micropump generates pulsatile shear stress in a widely adjustable physiological range within a microchannel circuit entirely covered on all fluid contact surfaces with human dermal microvascular endothelial cells. This microvascular transport system can be reproducibly established within four days, independently of the individual endothelial cell donor background. It interconnects two standard tissue culture compartments, each of 5 mm diameter, through microfluidic channels of 500 μm width. Further vessel branching and vessel diameter reduction down to a microvessel scale of approximately 40 μm width was realised by a two-photon laser ablation technique applied to inserts, designed for the convenient establishment of individual organ equivalents in the tissue culture compartments at a later time. The chip layout ensures physiological fluid-to-tissue ratios. Moreover, an in-depth microscopic analysis revealed the fine-tuned adjustment of endothelial cell behaviour to local shear stresses along the microvasculature of the system. Time-lapse and 3D imaging two-photon microscopy were used to visualise details of spatiotemporal adherence of the endothelial cells to the channel system and to each other. The first indicative long-term experiments revealed stable performance over two and four weeks. The potential application of this system for the future establishment of human-on-a-chip systems and basic human endothelial cell research is discussed.BMBF, 0315569, GO-Bio 3: Multi-Organ-Bioreaktoren für die prädiktive Substanztestung im Chipforma

Genetic variability of six indigenous goat breeds using major histocompatibility complex-associated microsatellite markers

The present study aimed at analyzing the genetic variability of indigenous goat breeds (Capra hircus) using the MHC-associated microsatellite markers BF1, BM1818, BM1258, DYMS1, and SMHCC1. The following breeds were included: Chinese Xuhuai, Indian Changthangi and Pashmina, Kenyan Small East African (SEA) and Galla, and Albanian Vendi. To examine genetic variability, the levels of heterozigosity, degrees of inbreeding, and genetic differences among the breeds were analyzed. The mean number of alleles ranged from nine in the Galla to 14.5 in the Vendi breed. The mean observed heterozygosity and mean expected heterozygosity varied from 0.483 in the Vendi to 0.577 in the Galla breed, and from 0.767 in the SEA to 0.879 in the Vendi breed, respectively. Significant loss of heterozygosity (p < 0.01) indicated that these loci were not in Hardy-Weinberg equilibrium. The mean FIS values ranged from 0.3299 in the SEA to 0.4605 in the Vendi breed with a mean value of 0.3623 in all breeds (p < 0.001). Analysis of molecular variance indicated that 7.14% and 4.74% genetic variation existed among the different breeds and geographic groups, whereas 92.86% and 95.26% existed in the breeds and the geographic groups, respectively (p < 0.001). The microsatellite marker analysis disclosed a high degree of genetic polymorphism. Loss of heterozygosity could be due to genetic drift and endogamy. The genetic variation among populations and geographic groups does not indicate a correlation of genetic differences with geographic distance

Pigous Beitrag zur Nachhaltigkeitsökonomie

Aufbauend auf Vorarbeiten von Sidgwick und Marshall, und gestützt auf einen ethisch fundierten sowie ökonomisch operationalisierten Wohlfahrtsbegriff entwickelt Pigou ein Konzept externer Effekte, das er auch auf Umweltprobleme anwendet. Im Gegensatz zu Marshall unterscheidet Pigou zwischen positiven und negativen externen Effekten, auch wenn er diese Begriffe selbst noch nicht verwendet. Pigou erkennt, dass Externalitäten ein zweischneidiges Schwert sind und verweist darauf, dass externe Effekte nicht lediglich auf Unternehmen sondern auch auf Privatpersonen wirken können. Von besonderer Bedeutung sind dabei intra- wie intergenerationale Umwelt- und Ressourcenprobleme. Pigou entwickelt zudem präziser als Sidgwick das Konzept von staatlichen Subventions- und Steuerlösungen zur Internalisierung externer Effekte, tritt deutlich für deren Einsatz zur Erhöhung des Volkseinkommens ein und plädiert nachdrücklich für eine staatliche Interventionspolitik. Pigous Definition externer Effekte und seine Ideen zur Angleichung des privaten und sozialen Wertgrenzprodukts durch Steuern und Subventionen bilden bis heute eine Grundlage des ökonomischen Denkens über Marktversagen und wohlfahrtserhöhende staatliche Interventionen

Impact of vibrationally resolved H2 on particle balance in Eirene simulations

| openaire: EC/H2020/633053/EU//EUROfusion Funding Information: The authors would like to thank Professor U. Fantz and Professor D. Reiter for valuable discussions enabling this work. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under grant agreement number 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work was supported by the Academy of Finland under grant no. 13330050. Publisher Copyright: © 2022 The Authors. Contributions to Plasma Physics published by Wiley-VCH GmbH.To evaluate the impact of transport of metastable, vibrationally excited states of the hydrogen molecule in dense and cold plasmas each vibrational state must be simulated as an individual species. Eirene neutral gas simulations of a one-dimensional flux-tube using a metastable-resolved model indicate a 30–50% decrease in the effective dissociation rate compared to simulations using a metastable-unresolved setup, which consider a single molecular species. Zero-dimensional Eirene simulations omitting transport effects predict a 25–65% decrease in the effective dissociation rate due to differences between the metastable-unresolved AMJUEL and the metastable-resolved H2VIBR rates available in Eirene. The exclusion of molecular hydrogen depletion via electronically excited states and vibrational transitions (Formula presented.) from the metastable-resolved rates reduce the effective dissociation rate. By accounting for the difference caused by the different collisional-radiative treatment of the metastable-resolved rates compared to the metastable-unresolved rates, transport effects are expected to be relevant under detached divertor conditions. It is, however, not possible to individually assess the role of the collisional-radiative processes and transport on the effective dissociation rate using the currently available atomic and molecular rates for the metastable-resolved and metastable-unresolved Eirene setups.Peer reviewe

Nitrogen molecular break-up and transport simulations in the JET divertor

| openaire: EC/H2020/633053/EU//EUROfusionThe density of N+ ions is predicted to decrease by 25 % and the density of N2+ ions to increase by 50 % if nitrogen is assumed to recycle from the divertor walls as molecules in partially detached JET L-mode plasma simulations performed with the 3D Monte Carlo trace impurity code ERO2.0 [1]. These findings are attributed to the kinetic energy gained by the molecular dissociation fragments in the Franck-Condon process and the resulting increase in plasma penetration of the atoms.Non peer reviewe

Combination of micro-macro and spatially hybrid fluid-kinetic approach for hydrogenic plasma edge neutrals

| openaire: EC/H2020/633053/EU//EUROfusionA new hybrid fluid-kinetic approach for the hydrogenic neutrals (atoms and molecules) in the plasma edge is presented. The hybrid approach combines a fully kinetic model for the atoms in the low-collisional regions near the vessel wall, and for the molecules in the whole plasma edge domain, with a micro-macro approach for atoms originating from recycling at the divertor targets, volumetric recombination, and dissociation of molecules. With the micro-macro approach, the originally scattering-dominated collision term due to charge-exchange collisions in the kinetic equation is transformed to an absorption-dominated term, while a large part of the neutral population is treated through a fluid approach. For JET L-mode plasmas, the premature termination of Monte Carlo particle trajectories in the hybrid approach leads to a reduction of the CPU time by approximately a factor 3 for a high-recycling case and by approximately a factor 11 for a partially detached case compared with a simulation with fully kinetic neutrals and the same amount of particles. For coupled fluid plasma - hybrid neutral simulations - the hybrid approach predicts the plasma divertor target profiles with a maximum hybrid-kinetic discrepancy of approximately 30%.Peer reviewe