Low-temperature rectification represents the state-of the-art in olefin/paraffin separation. Adsorption on microporous coordination polymers could be a less energy and cost-intensive alternative. ...Especially zeolitic imidazolate frameworks, such as ZIF-8, exhibits an interesting adsorption behavior since alkanes are preferentially adsorbed in comparison with the corresponding olefins. The single-component adsorption isotherms and mixed gas breakthrough experiments of C sub(2) to C sub(4) hydrocarbons show the potential of ZIF-8 for olefin/paraffin separation.Original Abstract: Die Trennung von Olefin/Paraffin-Gemischen erfolgt nach derzeitigem Stand der Technik durch Tieftemperaturrektifikation. Eine Alternative zu diesem energie- und kostenintensiven Verfahren konnte die Adsorption an mikroporosen Koordinationspolymeren sein. Insbesondere zeolithische Imidazolatnetzwerke, beispielsweise das hier untersuchte ZIF-8, zeigen in dieser Hinsicht interessante Eigenschaften, da die Alkane gegenueber den Alkenen bevorzugt adsorbiert werden. Die im Rahmen dieser Arbeit aufgenommenen Reinstoffadsorptionsisothermen und Durchbruchsexperimente fuer C sub(2)- bis C sub(4)-Kohlenwasserstoffe demonstrieren das Potenzial dieses Adsorbens fuer die Olefin/Paraffin-Trennung.
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African trypanosomes escape many cellular and unspecific immune reactions by the expression of a protective barrier formed from a repertoire of several hundred genes encoding immunologically distinct ...variant surface glycoproteins (VSGs). All mature VSGs are glycosylphosphatidylionositol‐anchored and N‐glycosylated.
To study trypanosome‐specific post‐translational modifications of VSG, a cell‐free system capable of in vitro translation, translocation into the rough endoplasmic reticulum, N‐glycosylation and glycosylphosphatidylinositol‐anchor addition was established using lysates of the bloodstream form of Trypanosoma brucei. Monitoring protein synthesis by 35Smethionine incorporation, labeled protein bands were readily detected by fluorography following SDS/PAGE. Appearance of these bands increased during a time‐course of 45 min and was sensitive to cycloheximide but not chloramphenicol treatment. Efficiency of this system, in terms of incorporation of radiolabeled amino acids into newly formed proteins, is similar to reticulocyte lysates. The system does not, however, allow initiation of protein synthesis.
Depending on the clone used, immunoprecipitation revealed one or two newly formed VSG bands. Upon digestion with N‐glycosidase F these bands resulted in a single band of a lower apparent molecular mass, indicating that newly synthesized VSG underwent translocation and glycosylation in the cell‐free system. Biotinylation of VSG and a combination of precipitation with immobilized avidin and detection of VSG using antibodies specific for clones and cross‐reacting determinants revealed that newly formed VSG contained the glycosylphosphatidylinositol anchor.
The exposome encompasses an individual's exposure to exogenous chemicals, as well as endogenous chemicals that are produced or altered in response to external stressors. While the exposome concept ...has been established for human health, its principles can be extended to include broader ecological issues. The assessment of exposure is tightly interlinked with hazard assessment. Here, we explore if mechanistic understanding of the causal links between exposure and adverse effects on human health and the environment can be improved by integrating the exposome approach with the adverse outcome pathway (AOP) concept that structures and organizes the sequence of biological events from an initial molecular interaction of a chemical with a biological target to an adverse outcome. Complementing exposome research with the AOP concept may facilitate a mechanistic understanding of stress-induced adverse effects, examine the relative contributions from various components of the exposome, determine the primary risk drivers in complex mixtures, and promote an integrative assessment of chemical risks for both human and environmental health.
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•Mechanistic understanding of the causal links between exposure and adverse effects can be improved.•AOP concept enhances understanding the exposome and its impact on adverse outcome.•Exposome and AOP can connect human health and environmental risk assessment.•Mixtures should be included in AOP concept.
Epidemiological studies suggest an association between exposure to volatile organic compounds (VOCs) and adverse allergic and respiratory symptoms. However, whether VOCs exhibit a causal role as ...adjuvants in asthma development remains unclear.
To investigate the effect of VOC exposure on the development of allergic airway inflammation Balb/c mice were exposed to VOCs emitted by new polyvinylchloride (PVC) flooring, sensitized with ovalbumin (OVA) and characterized in acute and chronic murine asthma models. Furthermore, prevalent evaporated VOCs were analyzed and mice were exposed to selected single VOCs.
Exposure of mice to PVC flooring increased eosinophilic lung inflammation and OVA-specific IgE serum levels compared to un-exposed control mice. The increased inflammation was associated with elevated levels of Th2-cytokines. Long-term exposure to PVC flooring exacerbated chronic airway inflammation. VOCs with the highest concentrations emitted by new PVC flooring were N-methyl-2-pyrrolidone (NMP) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). Exposure to NMP or TXIB also increased the allergic immune response in OVA-sensitized mice. In vitro or in vivo exposure to NMP or TXIB reduced IL-12 production in maturing dendritic cells (DCs) and enhanced airway inflammation after adoptive DC transfer into Balb/c mice. At higher concentrations both VOCs induced oxidative stress demonstrated by increased isoprostane and glutathione-S-transferase-pi1 protein levels in the lung of non-sensitized mice. Treatment of PVC flooring-exposed mice with N-acetylcysteine prevented the VOC-induced increase of airway inflammation.
Our results demonstrate that exposure to VOCs may increase the allergic immune response by interfering with DC function and by inducing oxidative stress and has therefore to be considerate as risk factor for the development of allergic diseases.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Urbane Gemeinschaftsgärten sind aus der Stadt nicht mehr wegzudenken. Aus vereinzelten Pionierprojekten entstand im Laufe der vergangenen zwei Jahrzehnte ein Netzwerk von rund 1000 Initiativen. Als ...erdverbundene Orte haben sie das Potenzial, Stadt wie Gesellschaft grundlegend zu verändern. Doch was ist das Besondere an urbanen Gärten und warum sind sie unverzichtbar? Gemeinsam mit Autor*innen aus Wissenschaft, Forschung und Aktivismus beleuchten wir die unterschiedlichen Dimensionen der neuen urbanen Gartenbewegung - und loten ihre Rolle bei der Mitgestaltung einer menschen- und naturgerechten Stadt der Zukunft aus.
For the first time, this volume presents a geographically and phenomenologically broad range of case studies on late medieval changes of rule, from dynastic succession to conquest by force. The focus ...will be on the border regions of Latin Europe, political and cultural contact zones with distinctive dynamics. By presenting examples from the Canaries to Moscow and from Sicily to Norway, late medieval Europe will be covered in all its diversity.
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