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Early life exposure to per-and polyfluoroalkyl substances(PFASs):A critical review

Emerging Contaminants 2017年第2期3卷 55-68页

作者： Kerstin Winkens Robin Vestergren urs berger Ian TCousins Department of Environmental Science and Analytical Chemistry(ACES) Stockholm UniversitySE-10691 StockholmSweden Swedish Environmental Research Institute IVL SE-10031 StockholmSweden Department Analytical Chemistry Helmholtz Centre for Environmental Research(UFZ)DE-04318 LeipzigGermany

Due to the dynamic developmental processes during pregnancy,infancy,childhood and adolescence,exposure to PFASs is hypothesized to have the most pronounced negative effects during this *** this review we critically evaluate the current state of the science regarding human early life exposure processes(until 18 years of age)to per-and polyfluoroalkyl substances(PFASs).Efficient placental transfer of perfluoroalkyl acids(PFAAs)results in relatively high prenatal exposure compared with many neutral organic *** few biomonitoring studies that specifically target infants,toddlers and other children suggest relatively high serum concentrations of perfluorooctane sulfonic acid(PFOS)and perfluorooctanoic acid(PFOA)in early life with peak concentrations occurring sometime before the child reaches 20 *** peak in serum concentrations is most likely explained by exposure via breastfeeding,ingestion of house dust and/or specific contact events with consumer products leading to high body weight normalized estimated daily intakes(EDIs).Although children have higher EDIs of PFASs than adults,these are not always reflected by higher serum levels of PFASs in children in cross-sectional biomonitoring studies due to the confounding effect of age and birth cohort,and different exposure histories due to production *** exposure studies measuring internal and external exposure(for multiple pathways and PFASs)at several time points during early life are strongly encouraged to understand temporal changes in exposure of individual children.A better quantitative understanding of early life exposure processes would help to improve the validity of epidemiological studies and allow informed decisions regarding setting of regulatory thresholds and appropriate mitigation actions.

关键词： life exposure likely

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Water-to-air transfer of branched and linear PFOA:Influence of pH,concentration and water type

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Emerging Contaminants 2017年第1期3卷 46-53页

作者： Jana H.Johansson Hong Yan urs berger Ian T.Cousins Department of Environmental Science and Analytical Chemistry(ACES) Stockholm UniversitySvante Arrhenius v€ag 811418 StockholmSweden State Key Laboratory of Pollution Control and Resources Reuse College of Environmental Science and EngineeringTongji UniversityShanghaiChina Department Analytical Chemistry Helmholtz Centre for Environmental Research e UFZLeipzigGermany

The volatilisation of perfluorooctanoic acid(PFOA)was measured experimentally at a range of pH values using a previously published laboratory ***-to-air transfer was studied for five structural isomers,namely:the linear isomer(n-PFOA)and the four most commonly occurring branched isomers(3-,4-,5-and 6-PFOA).The influence of water concentration and water type on the pH-dependent waterto-air transfer was also investigated for *** water-to-air transfer was studied over the course of 48 h at pH values ranging from 0.2 to *** all experimental conditions tested,the volatilisation of PFOA was negligible at pH>*** experiments performed with MilliQ water,volatilisation increased with decreasing water *** experiments performed with tap water and lake water,maximum volatilisation was observed at pH *** concentration of PFOA in water had no influence on the pH value at which water-to-air transfer was observed(*** pH<2.5)for the concentration range tested(0.1e50 mg/L PFOA in deionised water).Although the percentage of PFOA volatilised was significantly different for the four branched isomers at low pH,volatilisation was not observed above pH 2.5 for any branched isomer suggesting that all PFOA isomers have a low ***,these laboratory results demonstrate that volatilisation of any structural isomer of PFOA from water is negligible at environmentally-relevant *** is unlikely that PFOA isomers will be fractionated in the environment as a result of volatilisation because it is a process of negligible environmental relevance.

关键词： PFOA Isomer Branched Acid dissociation pKa

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Spatial and Temporal Quantitative Analysis of Cell Division and Elongation Rate in Growing Wheat Leaves under Saline Conditions

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Journal of Integrative Plant Biology 2008年第1期50卷 76-83页

作者： urs Schmidhalter Chair of Plant Nutrition Technical University of MunichFreising D-85350Germany

Leaf growth in grasses is determined by the cell division and elongation rates, with the duration of cell elongation being one of the processes that is the most sensitive to salinity. Our objective was to investigate the distribution profiles of cell production, cell length and the duration of cell elongation in the growing zone of the wheat leaf during the steady growth phase. Plants were grown in loamy soil with or without 120 mmollL NaCI in a growth chamber, and harvested at day 3 after leaf 4 emerged. Results show that the elongation rate of leaf 4 was reduced by t20 mmollL NaCI during the steady growth phase. The distribution profile of the lengths of abaxial epidermal cells of leaf 4 during the steady growth stage shows a sigmoidal pattern along the leaf axis for both treatments. Although salinity did not affect or even increased the length of the epidermal cells in some locations in the growth zone compared to the control treatment, the final length of the epidermal cells was reduced by 14% at 120 mmollL NaCI. Thus, we concluded that the observed reduction in the leaf elongation rate derived in part from the reduced cell division rate and either the shortened cell elongation zone or shortened duration of cell elongation. This suggests that more attention should be paid to the effects of salinity on those properties of cell production and the period of cell maturation that are related to the properties of cell wall.

关键词： cell production epidermal cell length growth zone relative elemental growth rate salinity wheat.

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Effect of Salinity on the Composition, Number and Size of Epidermal Cells along the Mature Blade of Wheat Leaves

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Journal of Integrative Plant Biology 2007年第7期49卷 1016-1023页

作者： Yuncai Hu urs Schmidhalter Chair of Plant Nutrition Technical University of Munich D-85350 Freising Germany

Salinity inhibits leaf growth in association with changes in cell size. The objective of this study was to determine the spatial distributions of the composition, number and dimensions of epidermal cells in the mature blades of leaf four of wheat seedlings under saline conditions. Plants were grown in loamy soil either with or without 120 mmol/L NaCl in a growth chamber, and harvested after leaf four was fully developed. The results of the spatial distribution analyses of width along the blade showed that salinity not only reduced the width of the leaf blade, but that it also altered the distribution pattern of blade width along the leaf axis. The reduction in the final size of the leaf blade was associated with a reduction in the total number of epidermal cells and in their widths and lengths. This study also revealed the spatial effects of salinity on the blade and epidermal cell dimensions along the leaf axis. In particular, salinity inhibited the total cell number for interstomatal, sister and elongated cells, implying that cell division in wheat leaves is inhibited by salinity. However, the lengths of interstomatal cells were not affected by salinity （unlike those for the sister and elongated cells）, suggesting the relative contributions of cell length and numbers to the reduction in the final length of the blade under salinity is dependent on cell type.

关键词： cell length cell number leaf epidermis salinity wheat.

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Symmetric Periodic Orbits and Uniruled Real Liouville Domains

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Chinese Annals of Mathematics,Series B 2016年第4期37卷 607-624页

作者： urs FRAUENFELDER Otto van KOERT Department of Mathematics University of Augsburg Department of Mathematics and Research Institute of Mathematics Seoul National University

A real Liouville domain is a Liouville domain with an exact anti-symplectic involution. The authors call a real Liouville domain uniruled if there exists an invariant finite energy plane through every real point. Asymptotically, an invariant finite energy plane converges to a symmetric periodic orbit. In this note, they work out a criterion which guarantees uniruledness for real Liouville domains.

关键词： Symmetric periodic orbits Real symplectic manifolds Real uniruledness

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Do viral infections protect from or enhance type 1 diabetes and how can we tell the difference?

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Cellular & Molecular Immunology 2011年第3期8卷 193-198页

作者： urs Christen Matthias G von Herrath Pharmazentrum Frankfurt/ZAFES Klinikum der Goethe UniversitaätFrankfurt am MainGermany La Jolla Institute for Allergy and Immunology La JollaCAUSA

Virus infections have been implicated in both initiation of and protection from autoimmune diseases,such as type 1 diabetes(T1D).In this review we intend to reflect on recent evidence how viruses might on the one hand be involved in the pathogenesis of T1D and on the other hand induce a state of protection from autoimmune-mediated *** is important to acknowledge that human individuals encounter more than just one virus infection in their ***,it is important to integrate more than just one possible environmental triggering factor for autoimmune diseases to occur.

关键词： animal model enterovirus hygiene hypothesis molecular mimicry pathogens

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Wetting and its influence on the filtration ability of ceramic foam filters

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Particuology 2015年第1期13卷 50-57页

作者： Fabian Heuzeroth J?rg Fritzsche urs A.Peuker Institute of Mechanical Process Engineering and Mineral Processing

Deep bed filtration in aqueous media is a well-known process for solid-liquid separation. However, the use of deep bed filtration for the purification of metal melts is a relatively new field of application, In particular, the separation mechanism of metal melts filtration is a new area for investigation. The current paper aims at examining the influence of wetting on the filtration efficiency of ceramic foam filters that is an important feature of the metal melts filtration process. A model system was designed using water and alumina particles （〈200μm）. The particles and filter medium were coated to model poor wetting. Thus, examination of the influence of wetting on the adhesion energy and filtration performance was possible. Furthermore, the effect of fluid velocity was studied. To this end, the experiments were carried out under atmospheric conditions and at 20℃. The findings showed that poor wetting between the fluid and solid phase significantly increased the filtration efficiency.

关键词： Deep bed filtration Adhesion energy Atomic force microscopy Wetting

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Assessing the Suitability of Various Physiological Traits to Screen Wheat Genotypes for Salt Tolerance

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Journal of Integrative Plant Biology 2007年第9期49卷 1352-1360页

作者： Salah E. EI-Hendawy Yuncai Hu urs Schmidhalter Chair of Plant Nutrition Technical University Munich D-85350 Freising-Weihenstephan Germany Agronomy Department Faculty of Agriculture Suez Canal University Ismalia Egypt

Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels （control and 150 mmol/L NaCI） in a greenhouse. The physiological traits （ion contents in leaves and stems, i.e. Na^＋, Cl^-, K^＋, Ca^2＋）, the ratios of K^＋/Na^＋ and Ca^＋/Na^＋ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content （SPAD value）, and leaf water relations, were measured at different growth stages. The physiological traits except for Na^＋ and Cl^- in stems and the leaf transpiration rate at 150 mmol/L NaCI showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca^2＋ and Ca2^＋/Na^＋ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca^2＋ in plant tissues.

关键词： physiological traits salinity screening wheat genotypes.

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Influence of Soil Organic Carbon on Greenhouse Gas Emission Potential After Application of Biogas Residues or Cattle Slurry:Results from a Pot Experiment

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Pedosphere 2017年第5期27卷 807-821页

作者： gawan heintze tim eickenscheidt urs schmidhalter matthias drsler university of applied sciences weihenstephan-triesdorf Chair of Vegetation Ecology 85354Freising(Germany) technical university of munich Chair of Plant Nutrition85354 Freising(Germany)

A change in the European Union energy policy has markedly promoted the expansion of biogas production. Consequently, large amounts of nutrient-rich residues are being used as organic fertilizers. In this study, a pot experiment was conducted to simulate the high-risk situation of enhanced greenhouse gas （GHG） emissions following organic fertilizer application in energy maize cultivation. We hypothesized that cattle slurry application enhanced CO2 and N20 fluxes compared to biogas digestate because of the overall higher carbon （C） and nitrogen （N） input, and that higher levels of CO2 and N20 emissions could be expected by increasing soil organic C （SOC） and N contents. Biogas digestate and cattle slurry, at a rate of 150 kg NH＋-N ha-1, were incorporated into 3 soil types with low, medium, and high SOC contents （Cambisol, Mollic Gleysol, and Sapric Histosol, termed Clow, Cmedium, and Chigh, respectively）. The GHG exchange （CO2, CH4, and N20） was measured on 5 replicates over a period of 22 d using the closed chamber technique. The application of cattle slurry resulted in significantly higher CO2 and N20 fluxes compared to the application of biogas digestate. No differences were observed in CH4 exchange, which was close to zero for all treatments. Significantly higher CO2 emissions were observed in Chigh compared to the other two soil types, whereas the highest N20 emissions were observed in Cmedium. Thus, the results demonstrate the importance of soil type-adapted fertilization with respect to changing soil physical and environmental conditions.

关键词： C mineralization energy maize mineral soil N mineralization organic fertilization peatland

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Techno-economic analysis of green hydrogen as an energy-storage medium for commercial buildings

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Clean Energy 2023年第1期7卷 84-98页

作者： Rahul Rajeevkumar urs Assia Chadly Ameena Al Sumaiti Ahmad Mayyas Department of Industrial and Systems Engineering Khalifa UniversityAbu Dhabi 127788UAE Department of Electrical Engineering and Computer Science Advanced Power and Energy CenterKhalifa UniversityAbu Dhabi 127788UAE

Green-hydrogen production is vital in mitigating carbon emissions and is being adopted *** its transition to a more diverse energy mix with a bigger share for renewable energy,United Arab Emirates(UAE)has committed to investing billions of dollars in the production of green *** study presents the results of the techno-economic assessment of a green-hydrogen-based commercial-building microgrid design in the *** microgrid has been designed based on the building load demand,green-hydrogen production potential utilizing solar photovoltaic(PV)energy and discrete stack reversible fuel cell electricity generation during non-PV *** the current market conditions and the hot humid climate of the UAE,a performance analysis is derived to evaluate the technical and economic feasibility of this *** study aims at maximizing both the building microgrid’s independence from the main grid and its renewable *** results indicate that the designed system is capable of meeting three-quarters of its load demand independently from the main grid and is supported by a 78%renewable-energy *** economic analysis demonstrates a 3.117-$/kg levelized cost of hydrogen production and a 0.248-$/kWh levelized cost for storing hydrogen as ***,the levelized cost of system energy was found to be less than the current utility costs in the *** analysis shows the significant impact of the capital cost and discount rate on the levelized cost of hydrogen generation and storage.

关键词： fuel cell electrolyser green hydrogen microgrid photovoltaic

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