Danube University Krems

About: Danube University Krems is a education organization based out in Krems, Niederösterreich, Austria. It is known for research contribution in the topics: Stroke & Population. The organization has 498 authors who have published 1572 publications receiving 68797 citations.

Longitudinal variation in the nutritional quality of basal food sources and its effect on invertebrates and fish in subalpine rivers.

Abstract: There is growing recognition of the importance of food quality over quantity for aquatic consumers. In streams and rivers, most previous studies considered this primarily in terms of the quality of terrestrial leaf litter and importance of microbial conditioning. However, many recent studies suggest that algae are a more nutritional food source for riverine consumers than leaf litter. To date, few studies have quantified longitudinal shifts in the nutritional quality of basal food resources in river ecosystems and how these may affect consumers. We conducted a field investigation in a subalpine river ecosystem in Austria to investigate longitudinal variations in diet quality of basal food sources (submerged leaves and periphyton) and diet source dependence of stream consumers (invertebrate grazers, shredders, filterers and predators, and fish). Fatty acid (FA) profiles of basal food sources and their consumers were measured. Our results indicate systematic differences between the FA profiles of terrestrial leaves and aquatic biota, i.e., periphyton, invertebrates and fish. Submerged leaves contained very low proportions of long-chain polyunsaturated fatty acids (LC-PUFA), which were conversely rich in aquatic biota. While the FA composition of submerged leaves remained similar among sites, the LC-PUFA of periphyton increased longitudinally, which was associated with increasing nutrients from upstream to downstream. Longitudinal variations in periphyton LC-PUFA were reflected in the LC-PUFA of invertebrate grazers and shredders, and further tracked by invertebrate predators and fish. However, brown trout (Salmo trutta) contained a large proportion of docosahexaenoic acid (DHA, 22:6ω3), a LC-PUFA almost entirely missing in basal sources and invertebrates. The fish accumulated eicosapentaenoic acid (EPA, 20:5ω3) from invertebrate prey and may use this FA to synthesize DHA. Our results provide a nutritional perspective for river food web studies, emphasizing the importance of algal resources to consumer somatic growth and the need to account for the longitudinal shifts in the quality of these basal resources.

Removal of stabilizers from human serum albumin by adsorbents and dialysis used in blood purification.

Abstract: Introduction Human serum albumin (HSA) is a monomeric multi-domain protein that possesses an extraordinary binding capacity. It plays an important role in storing and transporting endogenous substances, metabolites, and drugs throughout the human circulatory system. Clinically, HSA is used to treat a variety of diseases such as hypovolemia, shock, burns, hemorrhage, and trauma in critically ill patients. Pharmaceutical-grade HSA contains the stabilizers sodium caprylate and N-acetyltryptophanate to protect the protein from oxidative stress and to stabilize it for heat treatment which is applied for virus inactivation. Material and methods The aim of this study was to determine if the two stabilizers can be depleted by adsorbent techniques. Several, adsorbents, some of them are in clinical use, were tested in batch and in a dynamic setup for their ability to remove the stabilizers. Furthermore, the removal of the stabilizers was tested using a pediatric high flux dialyzer. Results The outcome of this study shows that activated charcoal based adsorbents are more effective in removal of N-acetylthryptophanate, whereas polystyrene based adsorbents are better for the removal of caprylate from HSA solutions. An adsorbent cartridge which contains a mix of activated charcoal and polystyrene based material could be used to remove both stabilizers effectively. After 4 hours treatment with a high flux dialyzer, N-acetyltryptophanate was totally removed whereas 20% of caprylate remained in the HSA solution.

Evolution of magnetic vortex formation in micron-sized disks

Abstract: Automotive magnetic field sensing applications require a robust sensing concept. One way to meet the corresponding sensor requirements, such as a negligible hysteresis and a large linear working range, is to employ the vortex state. Consequently, the nucleation field H n of the vortex state becomes a highly important sensor parameter. In this study, we examine different factors that affect H n. Tunneling magnetoresistance spin-valve sensors with disk-shaped CoFeB free layers, which energetically favor the nucleation of the vortex state, are electrically characterized and compared with micromagnetic simulations. Phase transitions into intermediate magnetic states, such as various buckling states, the S-state, or the double vortex state, are extracted from hysteresis loops. The resulting phase diagrams show that the formation of the S-state only occurs below a thickness of approximately 25 nm, whereas the double vortex state nucleates frequently only above approximately 35 nm. Both the S- and double vortex states lower the nucleation field of the single vortex state compared to higher order buckling states. Understanding both the origin and the influence of the intermediate phases opens the way to designing a robust and reliable vortex sensor concept.Automotive magnetic field sensing applications require a robust sensing concept. One way to meet the corresponding sensor requirements, such as a negligible hysteresis and a large linear working range, is to employ the vortex state. Consequently, the nucleation field H n of the vortex state becomes a highly important sensor parameter. In this study, we examine different factors that affect H n. Tunneling magnetoresistance spin-valve sensors with disk-shaped CoFeB free layers, which energetically favor the nucleation of the vortex state, are electrically characterized and compared with micromagnetic simulations. Phase transitions into intermediate magnetic states, such as various buckling states, the S-state, or the double vortex state, are extracted from hysteresis loops. The resulting phase diagrams show that the formation of the S-state only occurs below a thickness of approximately 25 nm, whereas the double vortex state nucleates frequently only above approximately 35 nm. Both the S- and double...

Hot-film and calorimetric thermal air flow sensors realized with printed board technology

Abstract: . This paper addresses the development of flow sensors optimized for heating, ventilating, and air conditioning systems. The sensors are based on the printed circuit board technology facilitating robust, flexible (in terms of layout), and cost-effective devices. Two approaches for measuring fluid quantities like flow velocity over the whole cross section are investigated in this context. The first one relies on hot-film transduction and stands out for its simplicity, but also shows some severe limitations, which can be circumvented by the second approach based on calorimetric transduction. Supported by extensive numerical simulations, several sensor embodiments were investigated and fabricated. After experimental characterization, measurement and simulation results were compared, which turned out to be in good agreement.

The Repercussions of Business Process Modeling Notations on Mental Load and Mental Effort

Abstract: Over the last decade, plenty business process modeling notations emerged for the documentation of business processes in enterprises. During the learning of a modeling notation, an individual is confronted with a cognitive load that has an impact on the comprehension of a notation with its underlying formalisms and concepts. To address the cognitive load, this paper presents the results from an exploratory study, in which a sample of 94 participants, divided into novices, intermediates, and experts, needed to assess process models expressed in terms of eight different process modeling notations, i.e., BPMN 2.0, Declarative Process Modeling, eGantt Charts, EPCs, Flow Charts, IDEF3, Petri Nets, and UML Activity Diagrams. The study focus was set on the subjective comprehensibility and accessibility of process models reflecting participant’s cognitive load (i.e., mental load and mental effort). Based on the cognitive load, a factor reflecting the mental difficulty for comprehending process models in different modeling notations was derived. The results indicate that established modeling notations from industry (e.g., BPMN) should be the first choice for enterprises when striving for process management. Moreover, study insights may be used to determine which modeling notations should be taught for an introduction in process modeling or which notation is useful to teach and train process modelers or analysts.