Der Advanced Temkin Reactor - Anwendung eines neuen Laborreaktorkonzepts zur Testung von Katalysatorpellets am Beispiel der Vinylacetatsynthese und die Untersuchung deren Desaktivierung

Die Ergebnisse dieser Arbeit zeigen, dass das verwendete neue Laborreaktorkonzept des Advanced Temkin Reactor (ATR) hervorragend für die Testung von unzerkleinerten Katalysatorpelletmustern geeignet ist. Die Besonderheit des ATR liegt darin, das Reaktionsgemisch gleichmäßig um die einzelnen Katalysatorformlinge zu führen. Die Katalysatoren befinden sich dabei im Zentrum einer der Pelletform angepassten Kette von Kavitäten, die über enge Kanäle miteinander verbunden sind. Ketten einer bestimmten Anzahl von Kavitäten bilden Reaktormodule, die sowohl parallel für z.B. Screenings, als auch seriell verschaltet werden können. Die Stoff- und Wärmetransporteigenschaften des ATR wurden für kugelförmige Katalysatoren mittels Computional Fluid Dynamics am Beispiel der Vinylacetatsynthese simuliert. Zum Nachweis der Leistungsfähigkeit des ATR wurde eine Testapparatur konzipiert, gebaut und in Betrieb genommen, die eine Testung der Vinylacetatsynthese-Katalysatoren unter industrienahen Bedingungen ermöglichte. Die Ursachen und Mechanismen der beobachteten Desaktivierung wurde an über eine Woche gealterten Katalysatoren mittels BET, XRD, TG-MS, TEM, TEM-EDX, ICP-OES, XPS und WDX untersucht. Als Hauptursache der Desaktivierung wurde die Sinterung der Aktivmetallpartikel identifiziert. Weitere Beiträge durch Verkokung und Fouling von Palladium konnten nachgewiesen werden. Ergebnisse aus XPS-, EDX/WDX- und ICP-OES-Untersuchungen bestätigen die in der Literatur diskutierte Bildung einer oxidierten Palladiumspezies, welche als Transportintermediat einer chemisch assistierten Atommigration die Sinterung beschleunigt. Entgegen bisheriger Veröffentlichungen gibt es aber auch Hinweise auf die Bildung einer mobilen Goldspezies. Die Beobachtung signifikant wachsender Schalendicken von sowohl Palladium als auch Gold unterstreicht deren beider Existenz. TEM-EDX-Ergebnisse legen die Existenz einer hochdispersen Palladiumphase auf dem frischen Katalysator nahe, die erst infolge von Alterung und Sinterung sichtbar wird. Die Beeinflussung der Desaktivierungsrate wurde durch Variation sowohl der Schalendicke als auch der Reaktionsführung während der Anfahrphase untersucht

Assessing the Application Potential of Selected Ecosystem-Based, Low-Regret Coastal Protection Measures

Climate change and subsequent processes triggered by climate change demand novel assessments and protection schemes in coastal environments, as frequency and intensity of extreme events as well as mean sea water levels are expected to rise. Most often, conventional coastal engineering approaches are solely built for protection purposes, but often come with negative side-effects to the coastal environment and communities. During the last decade, new concepts in coastal engineering have started emerging. Several technical measures with an ecosystem-based design have been developed and, in some places, already implemented over the last decade. These low-regret measures, for instance green belts, coir fibers and porous submerged structures, reveal their full potential as stand-alone coastal protection or when used in combination with each other. They are believed – and in some cases documented – to be a better alternative or potential complement to conventional “hard” coastal engineering protection. Concrete examples are taken from the densely populated coastal area of Jakarta Utara (North Jakarta) and the National Capital Integrated Coastal Development (NCICD), showing benefits and further opportunities, but also challenges for applied low-regret coastal protection measures and ecosystem-based disaster risk reduction. An assessment of the application potential of three “soft” protection measures is given and discussed

C-Terminal truncation of NR2A subunits impairs synaptic but not extrasynaptic localization of NMDA receptors

NMDA receptors interact via the extended intracellular C-terminal domain of the NR2 subunits with constituents of the postsynaptic density for purposes of retention, clustering, and functional regulation at central excitatory synapses. To examine the role of the C-terminal domain of NR2A in the synaptic localization and function of NR2A-containing NMDA receptors in hippocampal Schaffer collateral–CA1 pyramidal cell synapses, we analyzed mice which express NR2A only in its C-terminally truncated form. In CA1 cell somata, the levels, activation, and deactivation kinetics of extrasynaptic NMDA receptor channels were comparable in wild-type and mutant NR2A^(ΔC/ΔC) mice. At CA1 cell synapses, however, the truncated receptors were less concentrated than their full-length counterparts, as indicated by immunodetection in cultured neurons, synaptosomes, and postsynaptic densities. In the mutant, the NMDA component of evoked EPSCs was reduced in a developmentally progressing manner and was even more reduced in miniature EPSCs (mEPSCs) elicited by spontaneous glutamate release. Moreover, pharmacologically isolated NMDA currents evoked by synaptic stimulation had longer latencies and displayed slower rise and decay times, even in the presence of an NR2B-specific antagonist. These data strongly suggest that the C-terminal domain of NR2A subunits is important for the precise synaptic arrangement of NMDA receptors

Rentabilität vegetabiler Düngemittel im ökologischen Gemüsebau am Beispiel eines süddeutschen Gemischtbetriebes

For a given organic farm with livestock and vegetable production in Southern Germany the economic viability of on farm produced legume seed meal as Plant Based Organic Fertiliser (PBOF) is analysed by means of a Linear Programming (LP) model in order to asses under which conditions such a fertiliser use may be profitable. Yields, labour demand and gross margins of the different farming activities are taken from data collections and adapted based on information provided by the farmer, whose specific crop rotation, labour and stable restrictions are also implemented in the LP model. Nitrogen supplies and demands of the different farming activities are drawn from data collections and information by plant scientists. Our calculations show that legume seed meal as PBOF is profitable in case that cheap purchasable organic nitrogen fertilisers are not available. In future, further model calculations shall show whether this result also holds for other farming and site conditions than those underlying the quite specific conditions of our model farm

Inkubationsversuche zum Einfluss von Sorte und Textur auf den Umsatz von Lupinenkörnerschroten im Boden bei unterschiedlichen Temperaturen

Organically produced legume seed meals are an upcoming alternative to established fast mineralising organic fertilisers based on plant and animal waste products with suspect origin (e.g. hornmeal). The turnover in soil was investigated with respect to the influence of legume variety and seed meal texture. Variety specific differences in net N mineralisation could be attributed to differences in C/N ratio and cellulose content. The influence of texture classes on net N mineralisation was considerably smaller than the influence of differences between the investigated species

Expectation-based types of voluntary sports clubs in regional sports federations

Sports federations as non-profit organizations play a crucial role for organized sports activities of the population. However, one key responsibility of sports federations is providing needs-based support services to affiliated member sports clubs. Due to limited resources and simultaneously increasing heterogeneous expectations from their member sports clubs, designing an appropriate service portfolio poses increasing difficulties for sports federations. This study addresses these challenges by analyzing member clubs’ expectations and identifying distinct expectation types to enable more individually designed services. To analyze the expectations of member clubs (n = 354), the explorative case study was carried out in a regional sports federation in Germany. The findings reveal that member clubs' expectations can be represented using six reliable factors. The subsequent cluster analysis indicates four different expectation-based club types with heterogenous profiles. Based on the z-standardized factor values, the identified club types were labelled as follows: (1) “People Promoters” (32%), (2) “Undemanding” (22%), (3) “Competition-oriented Self-administrators” (23%) and (4) “Demanding Communicators” (23%). The extracted clusters were also reflected and validated by other structural and organizational characteristics of the sports clubs. The extracted types provide a first empirical step to identify different expectation schemes regarding services of sports federations. These schemes enable managers of sports federations to professionalize their service portfolios and, at the same time, to design services contributing to the development of sports clubs in a more targeted manner

Reduction in corpora lutea number in obese melanocortin-4-receptor-deficient mice

Obese melanocortin-4-receptor-deficient (MC4R-/-) male mice are reported to have erectile dysfunction, while homozygous MC4R-/- female mice are apparently fertile. A recently established obese mouse strain, carrying an inactivating mutation in the MC4R gene, revealed difficulties in breeding for the homozygous female mice. This prompted us to determine the presence of follicles and corpora lutea (CL) in ovaries of MC4R-/- mice aged 3–6 months in comparison to wild type (MC4R+/+) littermates. Serial sections of formaldehyde-fixed ovaries of mice with vaginal signs of estrus and metestrus were assessed for the number of healthy and regressing follicles and CL. The number of CL, as an estimate for the ovulation rate, decreased to zero during aging in MC4R-/- mice. The number of small- (diameter 100–200 micrometer) and large-sized follicles namely antral follicles (diameter >200 micrometer) were slightly increased in MC4R-/- compared to MC4R+/+ mice. Greater differences were found in very large to cystic follicles, which were more numerous in MC4R-/- mice. The number of regressing antral follicles was higher in the MC4R-/- group compared to the MC4R+/+ group. This was associated with a wide range in the number of collapsed zonae pellucidae as the last remnants of regressed follicles. A conspicuous hypertrophy of the interstitial cells was noted in 6-month-old MC4R-/- mice. In conclusion, cystic follicles and the reduction in CL number point to a decreased ovulation rate in obese MC4R-/- mice

Nutritive und antinutritive Inhaltsstoffe in Körnerleguminosen: Einfluss von Jahr und Standort auf den Futterwert

Die meisten Körnerleguminosen enthalten antinutritive Substanzen, abhängig von den Sorten und den Wachstumsbedingungen. Ziel der Studie war es, verschiedene Körnerleguminosenarten zu vergleichen, um ihren Futterwert unter Berücksichtigung ihrer nutritiven und antinutritiven Inhaltsstoffe zu ermitteln. Die Feldversuche wurden 2012 und 2013 in Karelshaff, Colmar-Berg, in Luxemburg und 2014 und 2015 an der Hessischen Staatsdomäne Frankenhausen in Grebenstein durchgeführt. Erste Ergebnisse für antinutritive Inhaltsstoffe zeigen, dass die Standorte und die jährlichen Schwankungen einen Einfluss auf den Gehalt haben und stark von den in der Literatur angegebenen Werten abweichen können