The Maize Value Chain in Zambia: Dynamics and Resilience Towards Production Shocks

Zambia is a country whose food security largely depends on maize. In the light of expected structural maize deficits and the likely occurrence of shock events, the aim of this thesis is to test the resilience of the Zambian maize value chain towards production shocks in terms of food supply security, and to find policy recommendations on how to increase this resilience. To that end, I devised and applied a new framework for measuring resilience properties using System Dynamics, which relies on comparing the development of food security indicators between the base run and the respective shock scenario run of a simulation model. Results show that the value chain is quite resilient towards floods and exchange rate shocks, moderately vulnerable towards changes in fertilizer subsidy programmes, and very vulnerable towards droughts, especially prolonged ones. In general, the resilience of the value chain towards one-time shocks is good due to the existence of maize buffer stocks that people can consume when production is low. However, the value chain is not very resilient if faced with two or more different shocks, as buffer stocks are quickly depleted and maize demand cannot be serviced any more. The resilience properties are also strongly affected by demand adjustments of consumers in response to changing maize availability, and moderately affected by the distribution of maize in between the informal and formal value chain and the storage policies of FRA. The observed resilience properties can endogenously be improved using smart long-term maize storage policies that exploit surplus production years.GEO-SD360JMASV-SYS

Nicht alles, was "Fett" ist, macht dick : Fettsäuren - Botenstoffe von großem pharmazeutischen Interesse

Lipide sind essentielle Strukturelemente von Zellen. Sie sind unter anderem Hauptbestandteil von Membranen, die einerseits verschiedene Kompartimente innerhalb der Zelle gegeneinander abgrenzen und andererseits die Zelle nach außen abschotten. Membranen regulieren den Transport von Ionen, kleinen polaren Molekülen sowie peptidartigen Botenstoffen, da sie für viele Bestandteile des Organismus nicht oder nur wenig durchlässig (permeabel) sind

Selective non-steroidal glucocorticoid receptor agonists attenuate inflammation but do not impair intestinal epithelial cell restitution in vitro

Introduction: Despite the excellent anti-inflammatory and immunosuppressive action of glucocorticoids (GCs), their use for the treatment of inflammatory bowel disease (IBD) still carries significant risks in terms of frequently occurring severe side effects, such as the impairment of intestinal tissue repair. The recently-introduced selective glucocorticoid receptor (GR) agonists (SEGRAs) offer anti-inflammatory action comparable to that of common GCs, but with a reduced side effect profile. Methods: The in vitro effects of the non-steroidal SEGRAs Compound A (CpdA) and ZK216348, were investigated in intestinal epithelial cells and compared to those of Dexamethasone (Dex). GR translocation was shown by immunfluorescence and Western blot analysis. Trans-repressive effects were studied by means of NF-κB/p65 activity and IL-8 levels, trans-activation potency by reporter gene assay. Flow cytometry was used to assess apoptosis of cells exposed to SEGRAs. The effects on IEC-6 and HaCaT cell restitution were determined using an in vitro wound healing model, cell proliferation by BrdU assay. In addition, influences on the TGF-β- or EGF/ERK1/2/MAPK-pathway were evaluated by reporter gene assay, Western blot and qPCR analysis. Results: Dex, CpdA and ZK216348 were found to be functional GR agonists. In terms of trans-repression, CpdA and ZK216348 effectively inhibited NF-κB activity and IL-8 secretion, but showed less trans-activation potency. Furthermore, unlike SEGRAs, Dex caused a dose-dependent inhibition of cell restitution with no effect on cell proliferation. These differences in epithelial restitution were TGF-β-independent but Dex inhibited the EGF/ERK1/2/MAPK-pathway important for intestinal epithelial wound healing by induction of MKP-1 and Annexin-1 which was not affected by CpdA or ZK216348. Conclusion: Collectively, our results indicate that, while their anti-inflammatory activity is comparable to Dex, SEGRAs show fewer side effects with respect to wound healing. The fact that SEGRAs did not have a similar effect on cell restitution might be due to a different modulation of EGF/ERK1/2 MAPK signalling

Die Zünglein an der Waage : Eicosanoide und ihre Rolle bei physiologischen und pathophysiologischen Prozessen

Wie entsteht Schmerz? Und wie kann man ihn lindern? Um diese Fragen beantworten zu können, untersuchen Forscher eine Gruppe von Schlüsselmolekülen, die Eicosanoide, und ihre Abbauprodukte. Dabei machen sie immer wieder überraschende Entdeckungen: Blockiert man etwa durch Schmerzmittel wie Acetylsalicylsäure gezielt die Entstehung des Abbauprodukts Prostaglandin, schützt dies auch vor Krebs. Verhindert man die Entstehung von Leukotrienen, lassen sich allergische Reaktionen wie Asthma, aber auch Krebs, Osteoporose und Herz-Kreislauf-Erkrankungen beeinflussen