Donor contributions to the strengthening of the African peace and security architecture

"On the African continent the establishment of the African Union (AU) in the year 2003 was significant in terms of the development of a new African Peace and Security Architecture (APSA). In reaction to the African reform dynamics and the emerging international security agenda, external actors have begun to adjust their instruments and rethink their choices for action. New security concepts as well as recent approaches in development policy and other policy fields explicitly aim to support the peace and security architecture in Africa. When it comes to external support these developments have led to a search for changing approaches spanning foreign, security and development policy. This study sets out to analyse the new APSA in the context of changing concepts for external support to it." (author's abstract

Systemic versus localized coagulation activation contributing to organ failure in critically ill patients

In the pathogenesis of sepsis, inflammation and coagulation play a pivotal role. Increasing evidence points to an extensive cross-talk between these two systems, whereby inflammation not only leads to activation of coagulation but coagulation also considerably affects inflammatory activity. The intricate relationship between inflammation and coagulation may not only be relevant for vascular atherothrombotic disease in general but has in certain clinical settings considerable consequences, for example in the pathogenesis of microvascular failure and subsequent multiple organ failure, as a result of severe infection and the associated systemic inflammatory response. Molecular pathways that contribute to inflammation-induced activation of coagulation have been precisely identified. Pro-inflammatory cytokines and other mediators are capable of activating the coagulation system and downregulating important physiological anticoagulant pathways. Activation of the coagulation system and ensuing thrombin generation is dependent on an interleukin-6-induced expression of tissue factor on activated mononuclear cells and endothelial cells and is insufficiently counteracted by physiological anticoagulant mechanisms and endogenous fibrinolysis. Interestingly, apart from the overall systemic responses, a differential local response in various vascular beds related to specific organs may occur

Investigations of the kinetics and mechanism of the selective methanation of CO in CO2 and H2-rich reformates over Ru supported catalysts

This PhD thesis will shine more light on the molecular mechanism of the CO and CO2 methanation over supported Ru catalysts and elucidate the physical origin of the driving force behind the selectivity for CO methanation specifically. This included two parts. First, the performance of commercial, supported Ru catalysts in the selective methanation of CO, various zeolite supported catalysts developed for these purposes and, for comparison, a standard Ru/Al2O3 catalyst was investigated. Second, the mechanistic details of the reaction were studied by various spectroscopic techniques, aiming at a physical understanding of the reaction mechanism and the resulting CO selectivities under conditions typical for selective methanation in H2-rich reformate gases

Mechanistic insights from transient changes of the water content during the selective methanation of CO over a Ru/γ-Al2_2O3_3 catalyst

The progress in low-temperature fuel cell based technologies poses a big challenge on the catalytic refinery processes used in ultra-purification of H2 from CO, which is a poison for the Pt anodes in fuel cells. [1] The selective methanation (SelMeth) of CO can be considered as an attractive alternative to the commonly used preferential oxidation of CO (PROX) for CO removal from H2-rich reformates down to ≤ 10 ppm. This is however, only applicable for catalysts which are highly selective for CO in the presence of up to 15 % CO2 in gas feeds. It could be demonstrated that small Ru NPs are intrinsically less active for the CO2 methanation, which result in higher selectivity for CO methanation. [4,5] In an earlier study on a Ru/γ-Al2O3 catalyst, we observed an increasing dispersion of Ru nanoparticles (NPs) with increasing amount of H2O in the reaction feed, going along with higher selectivity for CO methanation. [2] In the present contribution, we explored the physical reasons underlying the increase of Ru dispersion and selectivity in the presence of large amounts of H2O in the reaction feeds. For this purpose we studied transient changes in the activity / selectivity, and in Ru dispersion resulting from switches between wet and dry reaction conditions and vice versa

High Selectivity of Supported Ru Catalysts in the Selective CO MethanationWater Makes the Difference

The selectivity for CO methanation is a decisive aspect for the practical application of the methanation reaction for the removal of CO from CO₂-rich H₂ fuel gases produced via hydrocarbon reforming. We show that increasing the water content in the feed gas, up to technically relevant levels of 30%, significantly increases the selectivity of supported Ru catalysts compared with operation in (almost) dry gas, while in operando EXAFS measurements reveal a gradual decrease in the Ru particle size with increasing amounts of water in the gas feed. Consequences of these findings and related IR spectroscopic data for the mechanistic understanding and practical applications are outlined

CO methanation in CO2_2-rich reformate on supported Ru catalysts: Interplay between activation/reaction conditions, Ru particle size and selectivity

Supported Ru catalysts show a very high selectivity for the selective methanation of CO in CO2-rich H2 feeds. Based on a combination of kinetic measurements, in situ DRIFTS and in situ EXAFS measurements on Ru/zeolite and Ru/Al2O3 catalysts, the dependence of the selectivity on the Ru particle size will be shown, and how both of them depend on the nature of the support, the activation procedure and the reaction conditions, especially the water content in the reaction atmosphere. At low CO concentrations, in the absence of COad surface blocking, the selectivity always increases with decreasing Ru particle size, reflecting an inherently low activity for CO2 dissocia-tion of small Ru particle

Technical Approach Determines Inflammatory Response after Surgical and Transcatheter Aortic Valve Replacement

To investigate the periprocedural inflammatory response in patients with isolated aortic valve stenosis undergoing surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI) with different technical approaches.Patients were prospectively allocated to one of the following treatments: SAVR using conventional extracorporeal circulation (CECC, n = 47) or minimized extracorporeal circulation (MECC, n = 15), or TAVI using either transapical (TA, n = 15) or transfemoral (TF, n = 24) access. Exclusion criteria included infection, pre-procedural immunosuppressive or antibiotic drug therapy and emergency indications. We investigated interleukin (IL)-6, IL-8, IL-10, human leukocyte antigen (HLA-DR), white blood cell count, high-sensitivity C-reactive protein (hs-CRP) and soluble L-selectin (sCD62L) levels before the procedure and at 4, 24, and 48 h after aortic valve replacement. Data are presented for group interaction (p-values for inter-group comparison) as determined by the Greenhouse-Geisser correction.SAVR on CECC was associated with the highest levels of IL-8 and hs-CRP (p<0.017, and 0.007, respectively). SAVR on MECC showed the highest descent in levels of HLA-DR and sCD62L (both p<0.001) in the perioperative period. TA-TAVI showed increased intraprocedural concentration and the highest peak of IL-6 (p = 0.017). Significantly smaller changes in the inflammatory markers were observed in TF-TAVI.Surgical and interventional approaches to aortic valve replacement result in inflammatory modulation which differs according to the invasiveness of the procedure. As expected, extracorporeal circulation is associated with the most marked pro-inflammatory activation, whereas TF-TAVI emerges as the approach with the most attenuated inflammatory response. Factors such as the pre-treatment patient condition and the extent of myocardial injury also significantly affect inflammatory biomarker patterns. Accordingly, TA-TAVI is to be classified not as an interventional but a true surgical procedure, with inflammatory biomarker profiles comparable to those found after SAVR. Our study could not establish an obvious link between the extent of the periprocedural inflammatory response and clinical outcome parameters