Effects of ultra-purified polymerized bovine hemoglobin on local tissue oxygen tension in striated skin muscle - An efficacy study in the hamster

The development of hemoglobin-based oxygen carriers has been propagated for replacement of the oxygen carrying properties of red blood cells for almost one century. Using a Clark-type multi-wire oxygen surface electrode and the dorsal skin fold chamber model of the awake Syrian golden hamster, local tissue pO(2) was analyzed in the thin striated skin muscle before and after administration of an ultrapurified polymerized bovine hemoglobin solution (U-PBHb(R), Biopure Corp., Boston, Mass., USA) under the following experimental conditions: (a) hypervolemic infusion with U-PBHb at similar to 10% of calculated blood volume, and (b) isovolemic exchange transfusion with U-PBHb by replacing similar to50% of calculated blood volume. Control animals of group a received equivalent treatment with either isotonic saline or dextran 60, control animals of group b received dextran 60. Local tissue pO(2) was found slightly decreased after both hypervolemic infusion and isovolemic exchange transfusion with U-PBHb, while frequency distribution curves of local tissue pO(2) were found more narrow (less values 25 mm Hg), suggesting a more homogeneous tissue pO(2) distribution. The data thus indicate that U-PBHb slightly decreases mean tissue pO(2) after both hypervolemic infusion and isovolemic exchange transfusion which is accompanied by an effective homogenization of local tissue pO(2) distribution as compared to dextran 60. Copyright (C) 2002 S. Karger AG, Basel

Unrecognized controls on microbial functioning in Blue Carbon ecosystems: The role of mineral enzyme stabilization and allochthonous substrate supply

Tidal wetlands are effective carbon sinks, mitigating climate change through the long‐term removal of atmospheric CO2. Studies along surface‐elevation and thus flooding‐frequency gradients in tidal wetlands are often used to understand the effects of accelerated sea‐level rise on carbon sequestration, a process that is primarily determined by the balance of primary production and microbial decomposition. It has often been hypothesized that rates of microbial decomposition would increase with elevation and associated increases in soil oxygen availability; however, previous studies yield a wide range of outcomes and equivocal results. Our mechanistic understanding of the elevation–decomposition relationship is limited because most effort has been devoted to understanding the terminal steps of the decomposition process. A few studies assessed microbial exo‐enzyme activities (EEAs) as initial and rate‐limiting steps that often reveal important insight into microbial energy and nutrient constraints. The present study assessed EEAs and microbial abundance along a coastal ecotone stretching a flooding gradient from tidal flat to high marsh in the European Wadden Sea. We found that stabilization of exo‐enzymes to mineral sediments leads to high specific EEAs at low substrate concentrations in frequently flooded, sediment‐rich zones of the studied ecotone. We argue that the high background activity of a mineral‐associated enzyme pool provides a stable decomposition matrix in highly dynamic, frequently flooded zones. Furthermore, we demonstrate that microbial communities are less nutrient limited in frequently flooded zones, where inputs of nutrient‐rich marine organic matter are higher. This was reflected in both increasing exo‐enzymatic carbon versus nutrient acquisition and decreasing fungal versus bacterial abundance with increasing flooding frequency. Our findings thereby suggest two previously unrecognized mechanisms that may contribute to stimulated microbial activity despite decreasing oxygen availability in response to accelerated sea‐level rise

Fast approximation methods for credit portfolio risk calculations

Credit risk is one of the main risks financial institutions are exposed to. Within the last two decades, simulation-based credit portfolio models became extremely popular and replaced closed-form analytical ones as computers became more powerful. However, especially for non-homogenous and non-granular portfolios, a full simulation of a credit portfolio model is still time consuming, which can be disadvantageous within some use cases like credit pricing or within stress testing situations where results must be available very quickly. For this purpose, we investigate if methods based on artificial intelligence (AI) can be helpful to approximate a credit portfolio model. We compare the performance of AI-based methods within three different use cases with suitable non AI-based regression methods. As a result, we see that AI-based methods can generally capture portfolio characteristics and speed-up calculations but - depending on the specific use case and the availability of training data - they are not necessarily always the best choice. Particularly, considering the time and costs for collecting data and training of the complex algorithms, non-AI-based methods can be as good as or even better than AI-based ones, while requiring less computational effort

Dynamic Simulation of a solar tower system with open volumetic receiver - a review on the vICERP project

The paper presents an overview on the modeling and simulation activities of the virtual institute for central receiver power plants (vICERP). Within a three years launch period models and tools for dynamic simulation of central receiver power plants have been developed by the five research institutes involved. The models are based on the Modelica modeling language. Today, models for the heliostat field, the receiver, the air cycle, the thermal storage, and the water-steam cycle are available within the consortium. As a first application, the Solar Tower Jülich technology was used as a reference. Models are validated with real operational data from the Solar Tower Jülich

Wood-Veneer-Reinforced Mycelium Composites for Sustainable Building Components

The demand for building materials has been constantly increasing, which leads to excessive energy consumption for their provision. The looming environmental consequences have triggered the search for sustainable alternatives. Mycelium, as a rapidly renewable, low-carbon natural material that can withstand compressive forces and has inherent acoustic and fire-resistance properties, could be a potential solution to this problem. However, due to its low tensile, flexural and shear strength, mycelium is not currently widely used commercially in the construction industry. Therefore, this research focuses on improving the structural performance of mycelium composites for interior use through custom robotic additive manufacturing processes that integrate continuous wood fibers into the mycelial matrix as reinforcement. This creates a novel, 100% bio-based, wood-veneer-reinforced mycelium composite. As base materials, Ganoderma lucidum and hemp hurds for mycelium growth and maple veneer for reinforcement were pre-selected for this study. Compression, pull-out, and three-point bending tests comparing the unreinforced samples to the veneer-reinforced samples were performed, revealing improvements on the bending resistance of the reinforced samples. Additionally, the tensile strength of the reinforcement joints was examined and proved to be stronger than the material itself. The paper presents preliminary experiment results showing the effect of veneer reinforcements on increasing bending resistance, discusses the potential benefits of combining wood veneer and mycelium’s distinct material properties, and highlights methods for the design and production of architectural components

Arbeitsqualität und wirtschaftlicher Erfolg: Längsschnittstudie in deutschen Betrieben ; erster Zwischenbericht

Instrumente des Personalmanagements prägen in wesentlichen Bereichen die Qualität der Arbeit in Unternehmen und haben somit einen zentralen Einfluss auf die Motivation, die Bindung, die Effizienz und letztendlich auf die Produktivität der Mitarbeiterinnen und Mitarbeiter. Aus diesem Grund sind die Wirksamkeit von Instrumenten des Personalmanagements und deren Auswirkungen auf die Arbeitsqualität zunehmend in den Fokus von Wissenschaft, Wirtschaft und Öffentlichkeit gerückt. Während zahlreiche Unternehmensberatungen die Einführung vermeintlich wirksamer Instrumente des Personalmanagements bei Unternehmen anstoßen oder begleiten, arbeiten Wissenschaftler daran, die Verbreitung und die Wirksamkeit dieser Instrumente unter Berücksichtigung der Heterogenität der Unternehmen zu analysieren

Migration und räumliche Transformation: Theoretische Ansätze, empirische Erkenntnisse, interdisziplinäre Perspektiven

Migration hat es schon immer gegeben und wird voraussichtlich in Zukunft noch weiter zunehmen. Die Land-Stadt-Mobilität in Lateinamerika, Afrika und Asien führt gegenwärtig zu Megastäd-ten mit großen sozialen und infrastrukturellen Problemen. Küs-tenregionen, die durch hohe Besiedlungsdichte und starkes Be-völkerungswachstum geprägt sind, werden künftig von Klimawan-del noch stärker als bereits heute bedroht sein. Generell sind die Ursachen für Migration sehr vielschichtig. Grundsätzlich können positive wie negative Wirkungen von Migration auf Her-kunfts- wie Zielregionen gefunden werden. Zum einen können Herkunftsregionen von erheblichen Geldtransfers ihrer Auswan-derer*innen profitieren (Beispiel Mexiko), während in anderen Fällen die Geldtransfers die fehlenden Arbeitskräfte im länd-lichen Raum nicht aufwiegen können (Beispiel Tansania). Eben-falls sind die Auswirkungen der Migration auf ihre Zielregio-nen divers. Aus historischer Sicht hatten Einwanderungsgruppen häufig an einer geringeren Wertschätzung zu leiden. Dabei hat-ten viele Zielregionen von den Neuankömmlingen profitiert (billige Arbeitskräfte, kulturelle Bereicherung etc.). Gene-rell ist wichtig zu betonen, dass der Mensch als in soziale Beziehungen eingebundener, kulturell und durch historische Prozesse geprägter Akteur in den Mittelpunkt der Migrations-forschung gestellt werden muss.Migration always existed and is expected to intensify in the future. Rural-urban mobility in Latin America, Africa and Asia is currently leading to megacities with major social and in-frastructural problems. Coastal regions, often characterized by large agglomerations with high population density and growth, are in particular highly exposed to climatic change, i.e. sea level rise. Thus, causes of migration are very di-verse and complex. In principle, positive and negative effects of migration exist in regions of origin and destination. Yet, regions of origin can benefit from significant transfers of funds from their emigrants (e.g. Mexico), while in other coun-tries, remittances cannot outweigh the lack of rural workers (e.g. Tanzania). Likewise, the impact of migration on their target regions is diverse. From a historical point of view, immigrant groups suffered from lower appreciation although many target regions benefited from the newcomers (cheap labor, cultural enrichment etc.). In general, it is important to em-phasize that human beings, as immersed in social relationships and shaped by culture and history, have to be placed at the center of research on migration

Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD