240 research outputs found

    Ein ungewöhnlich großer Schädel vom Auerochsen (Bos primigenius) aus dem letzten Interglazial von Groß-Rohrheim bei Darmstadt

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    Der bislang größte Schädel von Bos primigenius wurde in den Ablagerungen des Oberrheins von Groß-Rohrheim bei Darmstadt gefunden. Stratigraphisch wird er mit allergrößter Wahrscheinlichkeit dem letzten Interglazial zugeordnet. Die Maße übersteigen alle Messwerte, die von pleistozänen und holozänen Auerochsen Mitteleuropas bekannt sind. Vergleichbare Maße gibt es am ehesten aus dem Pleistozän von Italien. Das mag ein Hinweis auf besonders günstige ökologische Bedingungen sein, zumal der Auerochse in Groß-Rohrheim zusammen mit zahlreichen Resten von Hippopotamus amphibius gefunden wurde.researc

    Identification of Pesticide Transformation Products in Surface Water Using Suspect Screening Combined with National Monitoring Data

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    Pesticides are widespread anthropogenic chemicals and well-known environmental contaminants of concern. Much less is known about transformation products (TPs) of pesticides and their presence in the environment. We developed a novel suspect screening approach for not well-explored pesticides (n = 16) and pesticide TPs (n = 242) by integrating knowledge from national monitoring with high-resolution mass spectrometry data. Weekly time-integrated samples were collected in two Swedish agricultural streams using the novel Time-Integrating, MicroFlow, In-line Extraction (TIMFIE) sampler. The integration of national monitoring data in the screening approach increased the number of prioritized compounds approximately twofold (from 23 to 42). Ultimately, 11 pesticide TPs were confirmed by reference standards and 12 TPs were considered tentatively identified with varying levels of confidence. Semiquantification of the newly confirmed TPs indicated higher concentrations than their corresponding parent pesticides in some cases, which highlights concerns related to (unknown) pesticide TPs in the environment. Some TPs were present in the environment without co-occurrence of their corresponding parent compounds, indicating higher persistency or mobility of the identified TPs. This study showcased the benefits of integrating monitoring knowledge in this type of studies, with advantages for suspect screening performance and the possibility to increase relevance of future monitoring programs

    Design of an Intelligent, Modular IGBT/SiC Inverter Platform up to 400 kW for Fast Realization of New Test-Bench Concepts

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    This paper presents an intelligent, modular two level, three phase inverter platform for up to 1200 V DC-link voltage and 400 kW continuous power at 10 kHz switching frequency. It features an integrated signal processing system and various sensors, which allow standalone as well as cross-linked operation. Customizable software of the signal processing system allows easy adaption to different applications such as Active-Front-End (AFE), DC/DC-converters, Dual-Active-Bridges or Drive Inverters. Focus of this paper is a design guideline for an inverter platform which fulfills requirements of various applications with regard to sensor setup, control, failure management and monitoring. Design goal of the platform is a fast setup of new testbench concepts for academic research and novel applications

    Enhancing spectral quality in complex environmental matrices: Supporting suspect and non-target screening in zebra mussels with ion mobility

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    Identification of bioaccumulating contaminants of emerging concern (CECs) via suspect and non-target screening remains a challenging task. In this study, ion mobility separation with high-resolution mass spectrometry (IM-HRMS) was used to investigate the effects of drift time (DT) alignment on spectrum quality and peak annotation for screening of CECs in complex sample matrices using data independent acquisition (DIA). Data treatment approaches (Binary Sample Comparison) and prioritisation strategies (Halogen Match, co-occurrence of features in biota and the water phase) were explored in a case study on zebra mussel (Dreissena polymorpha) in Lake Ma center dot laren, Sweden's largest drinking water reservoir. DT alignment evidently improved the fragment spectrum quality by increasing the similarity score to reference spectra from on average (+/- standard deviation) 0.33 +/- 0.31 to 0.64 +/- 0.30 points, thus positively influencing structure elucidation efforts. Thirty-two features were tenta-tively identified at confidence level 3 or higher using MetFrag coupled with the new PubChemLite database, which included predicted collision cross-section values from CCSbase. The implementation of predicted mobility data was found to support compound annotation. This study illustrates a quantitative assessment of the benefits of IM-HRMS on spectral quality, which will enhance the performance of future screening studies of CECs in complex environmental matrices

    Are preserved coastal water bodies in Spanish Mediterranean basin impacted by human activity? Water quality evaluation using chemical and biological analyses

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    The Spanish Mediterranean basin is particularly susceptible to climate change and human activities, making it vulnerable to the influence of anthropogenic contaminants. Therefore, conducting comprehensive and exhaustive water quality assessment in relevant water bodies of this basin is pivotal. In this work, surface water samples from coastal lagoons or estuaries were collected across the Spanish Mediterranean coastline and subjected to target and suspect screening of 1,585 organic micropollutants by liquid chromatography coupled to ion mobility separation and high resolution mass spectrometry. In total, 91 organic micropollutants could be confirmed and 5 were tentatively identified, with pharmaceuticals and pesticides being the most prevalent groups of chemicals. Chemical analysis data was compared with data on bioanalysis of those samples (recurrent aryl hydrocarbon receptor (AhR) activation, and estrogenic receptor (ER) inhibition in wetland samples affected by wastewater streams). The number of identified organic contaminants containing aromatic rings could explain the AhR activation observed. For the ER antagonistic effects, predictions on estrogenic inhibition potency for the detected compounds were used to explain the activities observed. The integration of chemical analysis with bioanalytical observations allowed a comprehensive overview of the quality of the water bodies under study

    Light-Induced Mechanistic Divergence in Gold(I) Catalysis:Revisiting the Reactivity of Diazonium Salts

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    In a systematic study of the Au-catalyzed reaction of o-alkynylphenols with aryldiazonium salts, we find that essentially the same reaction conditions lead to a change in mechanism when a light source is applied. If the reaction is carried out at room temperature using a AuI catalyst, the diazonium salt undergoes electrophilic deauration of a vinyl AuI intermediate and provides access to substituted azobenzofurans. If the reaction mixture is irradiated with blue LED light, C−C bond formation due to N2-extrusion from the diazonium salt is realized selectively, using the same starting materials without the need for an additional photo(redox) catalyst under aerobic conditions. We report a series of experiments demonstrating that the same vinyl AuI intermediate is capable of producing the observed products under photolytic and thermal conditions. The finding that a vinyl AuI complex can directly, without the need for an additional photo(redox) catalyst, result in C−C bond formation under photolytic conditions is contrary to the proposed mechanistic pathways suggested in the literature till date and highlights that the role of oxidation state changes in photoredox catalysis involving Au is thus far only poorly understood and may hold surprises for the future. Computational results indicate that photochemical activation can occur directly from a donor–acceptor complex formed between the vinyl AuI intermediate and the diazonium salt

    Ecosystem mapping in the Central Arctic Ocean (CAO) during the SAS-Oden expedition

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    As a result of global warming, the marine ecosystem around the North Pole, the Central Arctic Ocean (CAO), is in fast transition from a permanently to a seasonally ice-covered ocean. The sea-ice loss is expected to enable summer access to the CAO for non-icebreaking ships, including fishery vessels, in the near future1. However, the lack of knowledge on the CAO ecosystem impedes any assessment of the sustainability of potential future fisheries in the CAO. Taking a precautionary approach, the EU and nine countries in October 2018 signed the Agreement to Prevent Unregulated High Seas Fisheries in the Central Arctic Ocean. This agreement entered into force in June 2021 and a.o. requires the establishment of a joint scientific program to improve the understanding of the CAO ecosystem, including mapping and monitoring. To reduce the existing lack of knowledge, 12 scientists from the EFICA Consortium participated, together with 26 other on-board scientists, in sampling and data collection of ecosystem data during the Swedish SAS-Oden expedition in summer 2021. This report describes the field work performed by the EFICA scientists using water-column acoustics, deep-sea optical observations, and fish, zooplankton, sediment otolith and eDNA sampling for targeting fish, zooplankton and mammals. Further ecosystem data (physical, chemical and biological) were collected by the EFICA scientists in collaboration with other scientists on-board. Together with this report, a metadata database containing lists of all collected samples and data that are relevant for future fish-stock modelling and assessment studies was delivered to the European Commission

    What's in the water? – Target and suspect screening of contaminants of emerging concern in raw water and drinking water from Europe and Asia

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    There is growing worry that drinking water can be affected by contaminants of emerging concern (CECs), potentially threatening human health. In this study, a wide range of CECs ( n = 177), including pharmaceuticals, pesticides, perfluoroalkyl substances (PFASs) and other compounds, were analysed in raw water and in drinking water collected from drinking water treatment plants (DWTPs) in Europe and Asia ( n = 13). The impact of human activities was reflected in large numbers of compounds detected ( n = 115) and high variation in concentrations in the raw water (range 15-7995 ng L & minus;1 for E177 CECs). The variation was less pronounced in drinking water, with total concentration ranging from 35 to 919 ng L & minus;1 . Treatment efficiency was on average 65 +/- 28%, with wide variation between different DWTPs. The DWTP with the highest ECEC concentrations in raw water had the most efficient treatment procedure (average treatment efficiency 89%), whereas the DWTP with the lowest E177 CEC concentration in the raw water had the lowest average treatment efficiency (2.3%). Suspect screening was performed for 500 compounds ranked high as chemicals of concern for drinking water, using a prioritisation tool (SusTool). Overall, 208 features of interest were discovered and three were confirmed with reference standards. There was co-variation between removal efficiency in DWTPs for the target compounds and the suspected features detected using suspect screening, implying that removal of known contaminants can be used to predict overall removal of potential CECs for drinking water production. Our results can be of high value for DWTPs around the globe in their planning for future treatment strategies to meet the increasing concern about human ex-posure to unknown CECs present in their drinking water.(c) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/
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