Anwendung der Habitatmodellierung zur integrativen Bewertung von Schwall und Restwasser im Bereich der Wasserkraftnutzung

The current and future use of water power as a cost-effective and renewable energy source are increasingly leading to conflicts of interest between the declared environmental protection goals of the EU Water Framework Directive and the water energy sector. As such, it has become necessary to objectively assess and quantify the potential impacts of using water power on those biological quality criteria that are relevant for the Water Framework Directive, and to do so on a case-by-case basis. With the help of selected case studies, this paper offers insights into the applicability of habitat modeling as an integrative planning and assessment tool with regard to addressing peak and residual flow problems. The results of habitat modeling-based peak flow assessment conducted on the Alpenrhein and on the Enns indicate that the potential negative consequences for aquatic fauna cannot accurately be predicted without taking into account the river-type-dependent and river-reach-dependent morphological differences. They also clearly show the importance of season-based assessments of the peak flow problems, as, given the seasonal differences in discharge and water levels, basing an assessment on only one season would not be representative. Further, a study conducted on the Ybbs demonstrates how habitat modeling can be used to determine an ecologically sound residual flow level for typical local fish fauna.     

Failure of a bus hoisting platform due to unexpected system behaviour

A bus hoisting platform showed an unexpected behaviour under asymmetric loading. In order to assess the internal restraints and joint forces which had not been considered properly in initial design, a numerical approach was chosen. With a multi-body simulation tool, the loads were calculated for different system configurations and loading situations. The identified loads were used for the stress analysis of individual components (analytical and numerical with FEM). The results revealed joint forces of a higher order than the total external load, which was a consequence of first the underestimated internal loads due to unapparent horizontal force components in the statically indeterminate system, and second, the implemented force control of the hydraulic actuators working in parallel. The correctly identified high internal loads explained the peculiar observations and lead to an insufficient fatigue strength of the welded structure.     

Comparing the effects of mobile computers and traditional approaches in environmental education

Environmental education and computers? That was traditionally seen as an antagonism. But environmental educators who compete for attention and face new challenges in an age of mobile devices, have begun to explore the opportunities that mobile computers may offer in supporting environmental learning experiences. This study investigates the impact of a mobile guide system on different parameters of environmental literacy in comparison to traditional instruments of environmental education (i.e. brochure, human guide). In a field experiment at a floodplain conservation site, 185 school children and 76 adults participated in a guided tour using different media. Despite the novelty of mobile devices and usability issues associated with the prototype mobile nature guide, participants using the computer-assisted medium achieved similar results concerning environmental literacy components. The computer as mobile guide can lead to an increase in environmental knowledge and in case of the children it can increase their motivation to engage in environmental education activities.     

Glucoraphanin extraction from Cardaria draba: Part 2. Countercurrent extraction,bioactivity and toxicity testing

Glucoraphanin is a potentially valuable plant compound that has shown efficacy in the treatment of hypertension and the removal of carcinogens in animals. Our recent work determined the optimum extraction conditions for the recovery of high amounts of glucoraphanin from the noxious weed Cardaria draba in a single‐staged batch extractor. In this study, a multiple contact, countercurrent flow extraction process was used to achieve further improvements in glucoraphanin recovery. The yield increased by 1.5 times when compared with a single, batch contact extraction. A three‐stage process was sufficient to extract over 90% of the glucoraphanin from C draba at a dry weight plant loading of 50 g dm^?3. The experimental results at several solids loadings agreed with the leaching theory and the theoretical model was used to predict the number of stages needed to extract all the glucoraphanin from C draba at high solids loadings. Finally the efficacy and toxicity of the crude glucoraphanin extracts were tested using hepatoma cells. The efficacy was found to be much higher than single‐stage extracts, confirming that cell efficacy is related to the increased quantity of glucoraphanin extracted due to countercurrent operation. The crude extract demonstrated negligible acute toxicity to the hepatoma cells. Copyright © 2005 Society of Chemical Industry     

Analysis of a 3-D system function measured for magnetic particle imaging

Magnetic particle imaging (MPI) is a new tomographic imaging approach that can quantitatively map magnetic nanoparticle distributions in vivo. It is capable of volumetric real-time imaging at particle concentrations low enough to enable clinical applications. For image reconstruction in 3-D MPI, a system function (SF) is used, which describes the relation between the acquired MPI signal and the spatial origin of the signal. The SF depends on the instrumental configuration, the applied field sequence, and the magnetic particle characteristics. Its properties reflect the quality of the spatial encoding process. This work presents a detailed analysis of a measured SF to give experimental evidence that 3-D MPI encodes information using a set of 3-D spatial patterns or basis functions that is stored in the SF. This resembles filling 3-D k-space in magnetic resonance imaging, but is faster since all information is gathered simultaneously over a broad acquisition bandwidth. A frequency domain analysis shows that the finest structures that can be encoded with the presented SF are as small as 0.6 mm. SF simulations are performed to demonstrate that larger particle cores extend the set of basis functions towards higher resolution and that the experimentally observed spatial patterns require the existence of particles with core sizes of about 30 nm in the calibration sample. A simple formula is presented that qualitatively describes the basis functions to be expected at a certain frequency.     

Exposure of an adult population to perfluorinated substances using duplicate diet portions and biomonitoring data

Because dietary intake is supposed to be an important route of human exposure we quantified the dietary intake of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), perfluorohexanoate (PFHxA), and perfluorooctane sulfonamide (PFOSA) using 214 duplicate diet samples. The study was carried out with a study population of 15 female and 16 male healthy subjects aged 16-45 years. The participants collected daily duplicate diet samples over seven consecutive days in 2005. Duplicate samples were homogenized and their ultrasonic extracts were cleaned up by SPE and subjected to HPLC-ESI-MS/MS. In addition, individual intakes were estimated based on blood levels of PFOS and PFOA using a pharmacokinetic model. Blood samples were collected once during the sampling period. The median (90th percentile) daily dietary intake of PFOS and PFOA was 1.4 ng/kg b.w. (3.8 ng/kg b.w.) and 2.9 ng/kg b.w. (8.4 ng/kg b.w.), respectively. PFHxS and PFHxA could be detected only in some samples above detection limit with median (maximum) daily intakes of 2.0 ng/kg b.w. (4.0 ng/kg b.w.) and 4.3 ng/kg b.w. (9.2 ng/kg b.w.), respectively. Because PFOSA could not be detected above the limit of detection of 0.2 ng/g f.w. this indirect route of exposure seems to be of less significance. Overall, the results of this study demonstrate that the German population is exposed to PFOS and PFOA, but the median dietary intake did not reach the recommended tolerable daily intake by far. Biomonitoring data predict an exposure in a comparable range. We suppose that, normally, food intake is the main source of exposure of the general population to PFOS and PFOA.     

Screening of Phenolic Antioxidants in Edible Oils by HPTLC-DPPH Assay and MS Confirmation

The cytotoxicity of phenolic antioxidants had attracted marked attention, posing serious challenges to food safety. This paper presented a screening method for two major phenolic antioxidants (butylated hydroxytoluene and tert-butylhydroquinone) added in edible oils. To specifically visualize the targeted compounds after developing with toluene/ethyl acetate/methanol 8:1:1 (v/v/v) to 70 mm solvent front, the plate was subjected to a standardized 1,1-diphenyl-2-picrylhydrazyl assay. In addition to synoptical eye inspection, accurate quantification was realized by modified densitometric measurements: fluorescence mode, excitation wavelength 530 nm (D₂ and W lamp) without optical filter, which offered satisfactory sensitivity (8.5–17.5 mg/kg) and acceptable linearity (R²?>?0.999 within 50–200 ng/zone). Moreover, the established method was validated with edible oil samples, against EU Directive 2006/52/EC. Apart from that, the unambiguous confirmation of positive results was conveniently achieved by TLC-MS interface-mediated mass spectrometry. Featuring the merits of screening conception, the proposed method not only reached the goal of accurate quantification and conclusive identification of multi-phenolic antioxidants, but also excellently balanced the simplicity, detectability, and throughput of the screening workup. Therefore, it might be an attractive alternative to conventional methods.