TY - JOUR A1 - Meyer, Sören A1 - Matissek, M. A1 - Mueller, S. M. A1 - Taleshi, M. S. A1 - Ebert, Franziska A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - In vitro toxicological characterisation of three arsenic-containing hydrocarbons JF - Metallomics : integrated biometal science N2 - Arsenic-containing hydrocarbons are one group of fat-soluble organic arsenic compounds (arsenolipids) found in marine fish and other seafood. A risk assessment of arsenolipids is urgently needed, but has not been possible because of the total lack of toxicological data. In this study the cellular toxicity of three arsenic-containing hydrocarbons was investigated in cultured human bladder (UROtsa) and liver (HepG2) cells. Cytotoxicity of the arsenic-containing hydrocarbons was comparable to that of arsenite, which was applied as the toxic reference arsenical. A large cellular accumulation of arsenic, as measured by ICP-MS/MS, was observed after incubation of both cell lines with the arsenolipids. Moreover, the toxic mode of action shown by the three arsenic-containing hydrocarbons seemed to differ from that observed for arsenite. Evidence suggests that the high cytotoxic potential of the lipophilic arsenicals results from a decrease in the cellular energy level. This first in vitro based risk assessment cannot exclude a risk to human health related to the presence of arsenolipids in seafood, and indicates the urgent need for further toxicity studies in experimental animals to fully assess this possible risk. Y1 - 2014 U6 - https://doi.org/10.1039/c4mt00061g SN - 1756-5901 SN - 1756-591X VL - 6 IS - 5 SP - 1023 EP - 1033 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Aich, Valentin A1 - Liersch, Stefan A1 - Vetter, T. A1 - Huang, S. A1 - Tecklenburg, J. A1 - Hoffmann, P. A1 - Koch, H. A1 - Fournet, S. A1 - Krysanova, Valentina A1 - Mueller, N. A1 - Hattermann, Fred T1 - Comparing impacts of climate change on streamflow in four large African river basins JF - Hydrology and earth system sciences : HESS N2 - This study aims to compare impacts of climate change on streamflow in four large representative African river basins: the Niger, the Upper Blue Nile, the Oubangui and the Limpopo. We set up the eco-hydrological model SWIM (Soil and Water Integrated Model) for all four basins individually. The validation of the models for four basins shows results from adequate to very good, depending on the quality and availability of input and calibration data. For the climate impact assessment, we drive the model with outputs of five bias corrected Earth system models of Coupled Model Intercomparison Project Phase 5 (CMIP5) for the representative concentration pathways (RCPs) 2.6 and 8.5. This climate input is put into the context of climate trends of the whole African continent and compared to a CMIP5 ensemble of 19 models in order to test their representativeness. Subsequently, we compare the trends in mean discharges, seasonality and hydrological extremes in the 21st century. The uncertainty of results for all basins is high. Still, climate change impact is clearly visible for mean discharges but also for extremes in high and low flows. The uncertainty of the projections is the lowest in the Upper Blue Nile, where an increase in streamflow is most likely. In the Niger and the Limpopo basins, the magnitude of trends in both directions is high and has a wide range of uncertainty. In the Oubangui, impacts are the least significant. Our results confirm partly the findings of previous continental impact analyses for Africa. However, contradictory to these studies we find a tendency for increased streamflows in three of the four basins (not for the Oubangui). Guided by these results, we argue for attention to the possible risks of increasing high flows in the face of the dominant water scarcity in Africa. In conclusion, the study shows that impact intercomparisons have added value to the adaptation discussion and may be used for setting up adaptation plans in the context of a holistic approach. Y1 - 2014 U6 - https://doi.org/10.5194/hess-18-1305-2014 SN - 1027-5606 SN - 1607-7938 VL - 18 IS - 4 SP - 1305 EP - 1321 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Korup, Oliver A1 - Rixen, C. T1 - Soil erosion and organic carbon export by wet snow avalanches JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - Many mountain belts sustain prolonged snow cover for parts of the year, although enquiries into rates of erosion in these landscapes have focused almost exclusively on the snow-free periods. This raises the question of whether annual snow cover contributes significantly to modulating rates of erosion in high-relief terrain. In this context, the sudden release of snow avalanches is a frequent and potentially relevant process, judging from the physical damage to subalpine forest ecosystems, and the amount of debris contained in avalanche deposits. To quantitatively constrain this visual impression and to expand the sparse literature, we sampled sediment concentrations of n = 28 river-spanning snow-avalanche deposits (snow bridges) in the area around Davos, eastern Swiss Alps, and inferred an orders-of-magnitude variability in specific fine sediment and organic carbon yields (1.8 to 830 t km(-2) yr(-1), and 0.04 to 131 tC km(-2) yr(-1), respectively). A Monte Carlo simulation demonstrates that, with a minimum of free parameters, such variability is inherent to the geometric scaling used for computing specific yields. Moreover, the widely applied method of linearly extrapolating plot scale sample data may be prone to substantial under- or overestimates. A comparison of our inferred yields with previously published work demonstrates the relevance of wet snow avalanches as prominent agents of soil erosion and transporters of biogeochemical constituents to mountain rivers. Given that a number of snow bridges persisted below the insulating debris cover well into the summer months, snow-avalanche deposits also contribute to regulating in-channel sediment and organic debris storage on seasonal timescales. Finally, our results underline the potential shortcomings of neglecting erosional processes in the winter and spring months in mountainous terrain subjected to prominent snow cover. Y1 - 2014 U6 - https://doi.org/10.5194/tc-8-651-2014 SN - 1994-0416 SN - 1994-0424 VL - 8 IS - 2 SP - 651 EP - 658 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Albrecht, Torsten A1 - Levermann, Anders T1 - Fracture-induced softening for large-scale ice dynamics JF - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union N2 - Floating ice shelves can exert a retentive and hence stabilizing force onto the inland ice sheet of Antarctica. However, this effect has been observed to diminish by the dynamic effects of fracture processes within the protective ice shelves, leading to accelerated ice flow and hence to a sea-level contribution. In order to account for the macroscopic effect of fracture processes on large-scale viscous ice dynamics (i.e., ice-shelf scale) we apply a continuum representation of fractures and related fracture growth into the prognostic Parallel Ice Sheet Model (PISM) and compare the results to observations. To this end we introduce a higher order accuracy advection scheme for the transport of the two-dimensional fracture density across the regular computational grid. Dynamic coupling of fractures and ice flow is attained by a reduction of effective ice viscosity proportional to the inferred fracture density. This formulation implies the possibility of non-linear threshold behavior due to self-amplified fracturing in shear regions triggered by small variations in the fracture-initiation threshold. As a result of prognostic flow simulations, sharp across-flow velocity gradients appear in fracture-weakened regions. These modeled gradients compare well in magnitude and location with those in observed flow patterns. This model framework is in principle expandable to grounded ice streams and provides simple means of investigating climate-induced effects on fracturing (e. g., hydro fracturing) and hence on the ice flow. It further constitutes a physically sound basis for an enhanced fracture-based calving parameterization. Y1 - 2014 U6 - https://doi.org/10.5194/tc-8-587-2014 SN - 1994-0416 SN - 1994-0424 VL - 8 IS - 2 SP - 587 EP - 605 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Mondal, Suvendu Sekhar A1 - Bhunia, Asamanjoy A1 - Kelling, Alexandra A1 - Schilde, Uwe A1 - Janiak, Christoph A1 - Holdt, Hans-Jürgen T1 - A supramolecular Co(II)(14)- metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent JF - Chemical communications N2 - The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)(2.) 6H(2)O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)(14)-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms. Y1 - 2014 U6 - https://doi.org/10.1039/c3cc49698h SN - 1359-7345 SN - 1364-548X VL - 50 IS - 41 SP - 5441 EP - 5443 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Jopp, Eilin A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - Prevention and anthropology JF - Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Screening is an important issue in medicine and is used to early identify unrecognised diseases in persons who are apparently in good health. Screening strongly relies on the concept of "normal values". Normal values are defined as values that are frequently observed in a population and usually range within certain statistical limits. Screening for obesity should start early as the prevalence of obesity consolidates already at early school age. Though widely practiced, measuring BMI is not the ultimate solution for detecting obesity. Children with high BMI may be "robust" in skeletal dimensions. Assessing skeletal robustness and in particularly assessing developmental tempo in adolescents are also important issues in health screening. Yet, in spite of the necessity of screening investigations, appropriate reference values are often missing. Meanwhile, new concepts of growth diagrams have been developed. Stage line diagrams are useful for tracking developmental processes over time. Functional data analyses have efficiently been used for analysing longitudinal growth in height and assessing the tempo of maturation. Convenient low-cost statistics have also been developed for generating synthetic national references. KW - screening KW - obesity KW - skeletal robustness KW - developmental tempo Y1 - 2014 U6 - https://doi.org/10.1127/0003-5548/2014/0384 SN - 0003-5548 VL - 71 IS - 1-2 SP - 135 EP - 141 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Sangoro, Joshia R. A1 - Iacob, C. A1 - Agapov, A. L. A1 - Wang, Yangyang A1 - Berdzinski, Stefan A1 - Rexhausen, Hans A1 - Strehmel, Veronika A1 - Friedrich, C. A1 - Sokolov, A. P. A1 - Kremer, F. T1 - Decoupling of ionic conductivity from structural dynamics in polymerized ionic liquids JF - Soft matter N2 - Charge transport and structural dynamics in low molecular weight and polymerized 1-vinyl-3-pentylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquids (ILs) are investigated by a combination of broadband dielectric spectroscopy, dynamic mechanical spectroscopy and differential scanning calorimetry. While the dc conductivity and fluidity exhibit practically identical temperature dependence for the non-polymerized IL, a significant decoupling of ionic conduction from structural dynamics is observed for the polymerized IL. In addition, the dc conductivity of the polymerized IL exceeds that of its molecular counterpart by four orders of magnitude at their respective calorimetric glass transition temperatures. This is attributed to the unusually high mobility of the anions especially at lower temperatures when the structural dynamics is significantly slowed down. A simple physical explanation of the possible origin of the remarkable decoupling of ionic conductivity from structural dynamics is proposed. Y1 - 2014 U6 - https://doi.org/10.1039/c3sm53202j SN - 1744-683X SN - 1744-6848 VL - 10 IS - 20 SP - 3536 EP - 3540 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Sarauli, David A1 - Xu, Chenggang A1 - Dietzel, Birgit A1 - Schulz, Burkhard A1 - Lisdat, Fred T1 - A multilayered sulfonated polyaniline network with entrapped pyrroloquinoline quinone-dependent glucose dehydrogenase: tunable direct bioelectrocatalysis JF - Journal of materials chemistry : B, Materials for biology and medicine N2 - A feasible approach to construct multilayer films of sulfonated polyanilines - PMSA1 and PABMSA1 containing different ratios of aniline, 2-methoxyaniline-5-sulfonic acid (MAS) and 3-aminobenzoic acid (AB), with the entrapped redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) on Au and ITO electrode surfaces, is described. The formation of layers has been followed and confirmed by electrochemical impedance spectroscopy (EIS), which demonstrates that the multilayer assembly can be achieved in a progressive and uniform manner. The gold and ITO electrodes subsequently modified with PMSA1:PQQ-GDH and PABMSA1 films are studied by cyclic voltammetry (CV) and UV-Vis spectroscopy which show a significant direct bioelectrocatalytical response to the oxidation of the substrate glucose without any additional mediator. This response correlates linearly with the number of deposited layers. Furthermore, the constructed polymer/enzyme multilayer system exhibits a rather good long-term stability, since the catalytic current response is maintained for more than 60% of the initial value even after two weeks of storage. This verifies that a productive interaction of the enzyme embedded in the film of substituted polyaniline can be used as a basis for the construction of bioelectronic units, which are useful as indicators for processes liberating glucose and allowing optical and electrochemical transduction. Y1 - 2014 U6 - https://doi.org/10.1039/c4tb00336e SN - 2050-750X SN - 2050-7518 VL - 2 IS - 21 SP - 3196 EP - 3203 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Feldmann, J. A1 - Albrecht, Torsten A1 - Khroulev, C. A1 - Pattyn, F. A1 - Levermann, Anders T1 - Resolution-dependent performance of grounding line motion in a shallow model compared with a full-Stokes model according to the MISMIP3d intercomparison JF - Journal of glaciology N2 - Making confident statements about the evolution of an ice-sheet shelf system with a numerical model requires the capability to reproduce the migration of the grounding line. Here we show that the shallow-ice approximation/shallow-shelf approximation hybrid-type Parallel Ice Sheet Model (PISM), with its recent improvements, is capable of modeling the grounding line motion in a perturbed ice-sheet shelf system. The model is set up according to the three-dimensional Marine Ice-Sheet Model Intercomparison Project (MISMIP3d), and simulations are carried out across a broad range of spatial resolutions. Using (1) a linear interpolation of the grounding line with locally interpolated basal friction and (2) an improved driving-stress computation across the grounding line, the reversibility of the grounding line (i.e. its retreat after an advance forced by a local perturbation of basal resistance) is captured by the model even at medium and low resolutions (Delta x > 10 km). The transient model response is qualitatively similar to that of higher-order models but reveals a higher initial sensitivity to perturbations on very short timescales. Our findings support the application of PISM to the Antarctic ice sheet from regional up to continental scales and on relatively low spatial resolutions. KW - glacier flow KW - ice dynamics KW - ice-sheet modelling Y1 - 2014 U6 - https://doi.org/10.3189/2014JoG13J093 SN - 0022-1430 SN - 1727-5652 VL - 60 IS - 220 SP - 353 EP - 360 PB - International Glaciological Society CY - Cambridge ER - TY - JOUR A1 - Troppmann, Britta A1 - Balfanz, Sabine A1 - Krach, Christian A1 - Baumann, Arnd A1 - Blenau, Wolfgang T1 - Characterization of an Invertebrate-Type Dopamine Receptor of the American Cockroach, Periplaneta americana JF - International journal of molecular sciences N2 - We have isolated a cDNA coding for a putative invertebrate-type dopamine receptor (Peadop2) from P. americana brain by using a PCR-based strategy. The mRNA is present in samples from brain and salivary glands. We analyzed the distribution of the PeaDOP2 receptor protein with specific affinity-purified polyclonal antibodies. On Western blots, PeaDOP2 was detected in protein samples from brain, subesophageal ganglion, thoracic ganglia, and salivary glands. In immunocytochemical experiments, we detected PeaDOP2 in neurons with their somata being located at the anterior edge of the medulla bilaterally innervating the optic lobes and projecting to the ventro-lateral protocerebrum. In order to determine the functional and pharmacological properties of the cloned receptor, we generated a cell line constitutively expressing PeaDOP2. Activation of PeaDOP2-expressing cells with dopamine induced an increase in intracellular cAMP. In contrast, a C-terminally truncated splice variant of this receptor did not exhibit any functional property by itself. The molecular and pharmacological characterization of the first dopamine receptor from P. americana provides the basis for forthcoming studies focusing on the significance of the dopaminergic system in cockroach behavior and physiology. KW - G-protein-coupled receptor KW - dopamine KW - insect KW - cellular signaling KW - salivary gland KW - biogenic amine Y1 - 2014 U6 - https://doi.org/10.3390/ijms15010629 SN - 1422-0067 VL - 15 IS - 1 SP - 629 EP - 653 PB - MDPI CY - Basel ER -