Open Access

Hantaviruses (family Bunyaviridae) are enveloped viruses with a segmented RNA genome of negative polarity. They can cause two different diseases in humans, the hemorrhagic fever with renal syndrome in Europe and Asia and the hantavirus cardiopulmonary syndrome in America. The transmission to humans is mainly indirect by inhalation of aerosolized virus-contaminated rodent excreta. In contrast to the initial assumption that hantaviruses are mainly carried by rodents, during the last years many novel hantaviruses were detected in shrews, moles and recently in bats. These findings raise important questions about the evolutionary history of hantaviruses, their host association and adaptation, the role and frequency of spillover infections and host switch events. This study aims to prove the presence, geographical distribution and host association of the rodent-borne Tula virus (TULV) and the shrew-associated Seewis virus (SWSV) in Central Europe. For this purpose, novel laboratory techniques for molecular and serological hantavirus detection were developed. Initially, a broad-spectrum molecular assay to identify small mammal species from Central Europe was developed. This novel assay is based on PCR amplification using degenerated primers targeting the cytochrome b (cyt b) gene, nucleotide sequence analysis of the amplified cyt b gene portion and followed by pairwise sequence comparison to published sequences using the BLAST function of GenBank. Different small mammal species prevalent in Central Europe could be determined by this new approach, including not only representatives of various Rodentia and Soricomorpha, but also representatives of the orders Erinaceomorpha, Lagomorpha, Carnivora and Chiroptera. For characterization of insectivore-borne hantavirus Thottapalayam virus (TPMV), specific monoclonal antibodies were generated that detect native virus in infected mammalian cells. For the detection of TPMV-specific antibodies, Asian house shrew Suncus murinus immunoglobulin G (IgG)-specific antibodies were produced in laboratory mice and rabbit. Using this anti-shrew IgG and recombinant TPMV nucleocapsid (N) protein, an indirect enzyme-linked immunosorbent assay (ELISA) was developed allowing the detection of TPMV N protein-specific antibodies in immunized and experimentally TPMV infected shrews. A Pan-Hantavirus SYBR-Green RT-qPCR was developed for the search to novel hantaviruses. By this novel RT-qPCR and other conventional RT-PCR approaches, TULV infections were identified for the first time in the Eurasian water vole Arvicola amphibius from different regions in Germany and Switzerland. The phylogenetic analyses of the different partial TULV small (S)-, medium (M)- and large (L)-genome segment sequences from A. amphibius, with those of Microtus arvalis- and M. agrestis-derived TULV lineages, revealed a geographical, but host-independent clustering and may suggest multiple TULV spillover or a potential host switch from M. arvalis or M. agrestis to A. amphibius. In a further comprehensive study, different shrew species (Sorex araneus, S. minutus, S. coronatus, and S. alpinus) were collected in Germany, Czech Republic, and Slovakia and screened by another L-segment-targeting Pan-Hantavirus RT-PCR approach. This screening revealed hantavirus L-segment sequences in a large number of S. araneus and a few S. minutus indicating a broad geographical distribution of this hantavirus. For detailed analyses, S-segment sequences were obtained, from S. araneus and S. minutus. The sequences demonstrated their similarity to SWSV sequences from Hungary, Finland, Austria and Germany. A detailed phylogenetic analysis showed low intra-cluster sequence variability, but high inter-cluster divergence suggesting a long-term SWSV evolution in local shrew populations. In conclusion, the investigations demonstrated a broad geographical distribution and multiple spillover infections of rodent-borne TULV and shrew-borne SWSV in Europe. The finding of putative spillover transmissions described here and in other studies underline the current problem of the hantavirus reservoir host definition. In contrast to the hypothesis of a long-standing hantavirus–rodent (small mammal) host coevolution, the investigations support a more dynamic evolutionary history of hantavirus diversification including spillover infections and host-switch events. In future in vitro and in vivo infection studies as well as field studies has to define factors determining the host specificity of these hantaviruses.

The arbuscular mycorrhizal fungi (AMF) interaction with plants has a major impact on the soil ecosystem. However, so far, only a few studies on AMF genetics have been performed and molecular information on the genetic diversity of AMF is limited. In this study a fundamental genetic characterization of the industrial isolate, Glomus sp. AMykor (AMykor GmbH, Bitterfeld, Germany) has been undertaken to increase the understanding of AMF genetic diversity. Based on phylogenetic analysis of partial rDNA sequences, Glomus sp. AMykor isolate was proposed to belong to the G. irregulare species together with the reference isolate, DAOM197198. To investigate if both isolates differ in their ploidy level, fluorescence in situ hybridization (FISH) was performed and mainly one or two hybridization signals per nucleus were observed in both isolates. It is suggested that they harbour at least two major rDNA sites and possibly two minor sites. The DNA content was estimated by means of flow cytometry (FC) and confirmed by Feulgen densitometry (FD). The calculated average DNA content per nucleus is 153.0 ± 3.6 Mb for the G. irregulare AMykor isolate and 154.8 ± 6.2 Mb for the DAOM197198 isolate. Since there are plenty criticisms coming recently of using rDNA sequence for fungal barcoding there is necessity of development other system for the identification to species level of Glomeromycotan fungi. The focus of this part of the study was the GiFRD gene encoding fumarate reductase enzyme for use as a potential candidate for AMP species determination. Unfortunately, observed sequence variations do not allow the discrimination of Glomeromycotan species. However, further analysis of enzyme encoded by GiFRD showed a possible role of fumarate reductase in AMF redox balance maintaining under oxygen deficient conditions. Using a yeast expression system, it has been demonstrated that the protein encoded by GiFRD has fumarate reductase activity. The functional expression of GiFRD in the S. cerevisiae fumarate reductase deletion mutant restored the ability of growth under anaerobiosis which indicated that Gifrdp is able to functionally complement the S. cerevisiae missing genes. The fact that GiFRD expression was present only in the asymbiotic stage confirmed existence of at least one metabolic pathway involved in anaerobic metabolism and suggested that AMF behave as a facultative anaerobe in asymbiotic stage.

The goal of this thesis was to study the systematic relationships within the superfamily Sylvioidea (Aves: Passeriformes) in general and within the closely related families Acrocephalidae and Locustellidae in particular, by means of DNA sequences. Sylvioidea itself and families therein were the focus of many studies based as well on morphological characters as on DNA. Due to their morphological similarity and their presumably rapid radiation most studies failed to solve relationships between sylvioidean families and also demarcations of single families and relations within are still in progress. In this study, an enlargement of previous datasets, both taxa and number of DNA sequences, and more sophisticated analysis methods were used to improve the resolution in Sylvioidea, Acrocephalidae and Locustellidae. In addition, the applicability of barcoding in Acrocephalidae was tested. The monophyly of Sylvioidea could be supported and the families Paridae and Remizidae, which were sometimes still included, clustered among the outgroup taxa. Four families, Nicatoridae, Panuridae, Alaudidae, and Macrosphenidae constitute basal splits within Sylvioidea. The division of the former sylviid/timaliid clade in five families, Sylviidae, Leiothrichidae, Pellorneidae, Timaliidae, and Zosteropidae was supported. Scotocerca, Erythrocercus, and Hylia, previously supposed to be members of Cettiidae, were shown not to belong to this family. As the three genera are also morphologically and ecologically different, they were here proposed to be elevated to family rank, Scotocercidae, Erythrocercidae and Hyliidae, respectively. The family Acrocephalidae consisted of the four genera, Nesillas, Acrocephalus, Hippolais, and Chloropeta. In the analysis for this thesis, the latter three appeared to be non-monophyletic. One Acrocephalus species, A. aedon was sister to a clade containing four species of Hippolais as well as two out of three Chloropeta species. They were all merged in the genus Iduna, based on the DNA evidence and shared morphological and ecological characters. Iduna had priority over Hippolais or Chloropeta according to the International Code of Zoological Nomenclature. The one remaining Chloropeta species (C. gracilirostris) had to be renamed to Calamonastides as Chloropeta was no longer available for this taxon. Seven genera were included in the re-analysis of the family Locustellidae: Locustella, Bradypterus, Megalurus, Dromaeocercus, Schoenicola, Cincloramphus, and Eremiornis. Apart from the monotypic genera Dromaeocercus and Eremiornis and Schoenicola, of which only one species was included, the remaining genera were found to be non-monophyletic. One clade contained all Locustella species, Megalurus pryeri and all Asian/Oriental Bradypterus species. All species in this clade were synonymized with Locustella, as the type species of Locustella was included, whereas the type species of Bradypterus fell in a different clade. Therefore, the remaining African Bradypterus species retained their genus name, and Dromaeocercus was renamed to Bradypterus as it clustered within Bradypterus. Cincloramphus, intermingling with the remaining Megalurus species, was synonymized with the latter. Barcoding, growing in popularity for delimiting species, was tested in its applicability for Acrocephalidae. Fourteen taxa currently recognized as full species would fall under the 2% threshold of sequence divergence proposed for delimiting species using the mitochondrial cytochrome b gene. It was also shown that it is important to clarify which part of a DNA sequence is used, as different parts can give different results regarding the 2% threshold. In addition, the choice of “complete deletion” or “pairwise deletion” in calculating genetic distances is important, if incomplete are sequences used.

In this thesis, all three BVMOs from Pseudomonas putida NCIMB10007, that were known to be responsible for the ability of this strain to degrade camphor since the 1950s were successfully made available as recombinant biocatalysts. While the genomic sequence of 2,5-DKCMO was available from the database, the genes encoding 3,6-DKCMO and OTEMO had to be identified using certain PCR-techniques first. All three enzymes were cloned into standard plasmids enabling convenient expression in E. coli facilitating the application of the enzymes in organic chemistry. Their synthetic potential was already reported during the 1990s, but at that time their efficient application was limited due to difficulties with respect to low production levels and insufficient purity and separation of enzyme fractions. These drawbacks are now overcome. Furthermore, biochemical characterization of the camphor-degrading BVMOs was performed including the substrate spectra of these enzymes. Thereby OTEMO turned out not only to have a broad substrate scope accepting mono- and bicyclic aliphatic and arylaliphatic ketones, but also to efficiently convert alpha/beta-unsaturated cycloalkanones due to the similarity of these compounds to OTEMOs natural substrate. Finally, the major limitation in the synthetic application of Type II BVMOs was addressed by searching a flavin-reductase suitable for coupling to these two-component oxygenases. Putative candidates from the respective P. putida strain were identified by the use of amino acid motifs conserved in other representatives of two-component systems. While these enzymes failed, flavin-reductase Fre from E. coli - that also contained the motifs - was shown to enhance the activity of the DKCMOs when applied as crude cell extract as well as pure enzyme. This finding represents a key step for future application of Type II BVMOs.

Acute pancreatitis is a common clinical inflammatory disease with variable severity from mild, self-limiting attacks to a severe lethal attack with a high mortality. In most of the cases, acute pancreatitis is either caused by gallstone obstruction or excessive alcohol consumption. Clinical symptoms include elevated levels (minimum 3 times than normal) of pancreatic enzymes such as amylase or lipase in serum. It is generally believed that earliest event in acute pancreatitis occur in acinar cells which includes premature protease activation and cytoplasmic vacuole formation. Premature trypsinogen activation has been considered as chief culprit as it can activate other proteases in a cascade like manner in acinar cells. Trypsin activity takes place in a biphasic curve with elevated levels at 1 h and 8 h in the initial stages up to 24 h in caerulein induced pancreatitis in mice. It has been shown that cytoplasmic vacuoles observed in pancreatitis are of autophagic nature. The role of autophagy for the disease onset and its role in trypsinogen is much of a debate. Hence, we studied the relation between autophagosome formation and trypsinogen activation in first 12h of pancreatitis. Although autophagosomes were found to be co-localised with trypsin in vivo, this was found to be a late event occuring only by 4 h. Substrate specific trypsin activity and western blotting from both sub-cellular fractions over the time course of pancreatitis and multiple fractions prepared from 1 h caerulein induced pancreatic tissue revealed that trypsin activity observed at 1 h occured in a zymogen enriched fraction. In line simultaneous confocal imaging of trypsin activity and autophagosome formation in hyperstimulated acini isolated from GFP-LC3 mice showed that both processes are independent and take place in parallel. Furthermore, protease inhibition by gabexate mesilate did not prevent autophagosome formation indicating that trypsinogen activation is not a prerequisite for vacuole formation. Even though, autophagosomes and active trypsin were found to be co-localised around 30 minutes to some degree upon cholecystokinin hyperstimulation, the earliest trypsin activation started to appear by 15 minutes and was independent of autophagosomes. The earliest active trypsin was found to be co-localised along with the cis-Golgi complex suggesting that the Golgi apparatus and its pre-condensed zymogen granules are the compartment responsible for the trypsinogen activation. 2) Protease activation in pancreatic acinar cells considered as the early hallmark event in the acute pancreatitis. However, the disease is aggravated by the infiltration of the leukocytes. Activated proteases mediate acinar cell injury and hereby cause the release of chemokines, which in turn attract inflammatory cells. Transmigrated inflammatory cells cause systemic damage that deteriorates the condition of the disease. Neutrophil elastase has been reported to be involved in the dissociation of cell-cell contact at adherens junctions by the extracellular cleavage of E-cadherin. This subsequently leads to transmigration of leukocytes into the epithelial tissue during the initial phase of experimental pancreatitis and aggravates the disease condition. On the other hand, pancreatic elastase substantially contributes to acinar cell necrosis. In this study, ZD0892, an orally bioavailable dual inhibitor against both elastases was tested for its efficacy to ameliorate severity in acute pancreatitis. ZD0892 orally fed mice showed increased survival compared to the control group in the taurocholate model of severe pancreatitis. In the initial stages of pancreatitis up to 24 h, the severity markers were found to be significantly lower in the inhibitor treated group. Treatment of mice with ZD0892 did not impede the defensive property of the leukocytes such as phagocytosis or oxidative burst. In caerulein induced pancreatitis, a mild form of acute pancreatitis, in rats, the local damage measured as serum amylase and lipase, wet dry ratio, and pancreatic myeloperoxidase levels were significantly lower in the inhibitor group. Systemic inflammatory parameters such as myeloperoxidase activity in lung was found to be significantly lower in the inhibitor fed rats. Inhibitor feeding resulted in lesser elastolytic activity compared to control group indicating that extracellular matrix was less damaged. Prophylactic treatment of pancreatitis with an orally available inhibitor with a dual specificity against pancreatic elastase and PMN-elastase was shown to ameliorate both local and systemic damage. Hence, in overall, ZD0892 treatment is proved to be beneficial to the mice and rats in experimental pancreatitis and should be considered for treatment in humans as the substance has been already studied in phase I and II trails for other indications.

The early clinical management of patients with polytrauma remains challenging. Clinical examination is unreliable in identifying the presence and severity of injuries, and diagnostic imaging plays a central role in the evaluation of the injury pattern. In the last decade, whole body multi slice computed tomography (Pan-CT) performed immediately after admission gained recognition in Europe and United States. Its utility and value, given the lack of accuracy data and concerns about unnecessary exposure to radiation, is undefined. The primary objective of this retrospective cohort study was to compare survival of multiple trauma (polytrauma) patients (Injury Severity Score [ISS] ≥ 16) prior to (1999 - 2002) and after (2002 - 2004) the introduction of a Pan-CT-based trauma resuscitation algorithm at a maximum care university medical centre. Secondary objectives were to compare the complication rates and duration of intensive care treatment. The study included 123 patients (mean age 34.6 years [SD 16.8], mean ISS 26.7 [SD 8.7]) in the control and 104 (mean age 39.8 years [SD 20.0], mean ISS 28.6 [SD 10.5]) patients in the intervention period. Die Baseline criteria were well balanced amongst both cohorts except for age (34.6 versus 39.8 years, p = 0.034). Both cohorts had a similar predicted probability of survival using the TRISS method (77.5 versus 77.6%, p = 0.979). Raw mortality decreased markedly but not statistically significantly in Pan-CT cohort (17.9 versus 11.5%, risk ratio (RR) 0.65, 95% confidence interval (CI) 0.34 - 1.24). However, after adjustment for injury severity, by mortality odds ratio of 0.40 (95% CI 0.17 – 0.95, p = 0.038) Pan-CT patients were 2.5 times more likely to survive. The mean difference in the duration of ICU treatment (5.1, 95% CI 1.2 – 9.0 days), days on respirator (5.3, 95% CI 2.0 - 8.6), and number of complications (0.4, 95% CI 0.2 – 0.8) was statistically significant and in favour of the Pan-CT-period.

Rainbow trout (Oncorhynchus mykiss) represents the third most produced species of diadromous fish, with the total production of 0,732 million tonnes in 2009. More than one third of this production comes from Europe, where it is dominated by Norway, Italy and France. Germany is the fifth biggest producer in Europe, producing 21 thousand tonnes of rainbow trout in the value of 6,1 million Euro. However, the conditions in the intensive aquaculture often increase the disease susceptibility to many pathogens. One of the highest economic threats for a salmonids aquaculture is the causative agent of furunculosis, Aeromonas salmonicida subsp. salmonicida. Several strategies have been developed to protect the fish, but the traditional methods are either laborious or represent a potential risk for the environment. The selective breeding established more than 35 years ago in the brackish waters of Baltic Sea represent a attractive alternative, delivering a novel strain of rainbow trout better adapted to the brackish environment and exhibiting reduced mortality in the infection with A.salmonicida. Nevertheless, no information was available about the fundaments of this phenomenon. Thus, the aim of presented study was the identification of immune adaptations, which occurred during the 30 years of selection and favoured increased survival of “born” trout to the bacterial diseas es. In the presented work, the peritoneal cavity of rainbow trout has been used as a model for the investigation of disease resistance in fish. In the first chapter, the peritoneal cavity has been described as a unique niche of teleost immune system and the kinetic of peritoneal leukocytes induced by the stimulation has been analysed. Furthermore, a unique set of monoclonal antibodies has been used to evaluate the contribution of distinct cell populations on the inflammation and its resolution. In the second part of the study, the transcriptional changes of peritoneal leukocytes have been evaluated using the GRASP microarray. The following analysis provided unique insights into the local immune response in rainbow trout. The unprecedented combination of both data sets offers an unparalleled description of the local immune response in teleost fish and can be summarized into following facts. In general, the obtained results revealed, that the unstimulated peritoneal cavity is populated predominantly by lymphocytes with IgM+ Bcells being the major cells type. The rapid changes in the composition induced by the stimulation were underlined by the upregulation of major proinflammatory molecules such as IL1β, IL8 and TNFα within 12hpi. Although the initial phase of the reaction was dominated by myeloid cells, the cavity underwent within 72 hours two complete changes in the composition corresponding with the massive changes in the transcriptome. Eventually, the resolution of inflammation was marked by an increasing number of lymphocytes and correlated with the downregulation of pro-inflammatory genes to the initial level and upregulation of anti-inflammatory cytokines IL10 and TGFβ. Besides the general observations common to all treatments and both strains, our experiments revealed also remarkable differences between the antigenic stimulation and reaction towards pathogen. From these differences following conclusions can be drawn; the infection induces comparable reaction pattern as the stimulation, although the intensity of the reaction and number of cells is higher. These observations correlated with the higher expression of inflammatory molecules after the infection. Viable bacteria also prolong the myeloid phase of the reaction and delay the resolution of inflammation. Finally, model of peritoneal inflammation caused by A. salmonicida has been applied also to the second strain of rainbow trout, known for its higher resistance to infection. The comparison of obtained data suggested that resistant trout reacted to the antigenic stimulation and infection with a lower number of cells despite minor differences in the expression level of major pro-inflammatory molecules during early stages of the infection. Eventually, the resolution of inflammation and onset of adaptive immune response occurred in resistant trout almost 24 hours earlier and was correlating with an increased expression of anti-inflammatory cytokines IL10 and TGFβ. Notably, the increased survival of resistant strain correlates with the increased expression of antibacterial proteins such as NRAMP and hepcidin. Taken together, obtained data provided unprecedented insights into the local immune response in teleost fish and identified features conserved during the selection breeding in the brackish water of Baltic Sea. Additionally, combination of cellular and molecular data elucidates the peritoneal inflammation in fish and suggested high conservation of the immune response in the evolution.

Particle and heat transport in fusion devices often exceed the neoclassical prediction. This anomalous transport is thought to be produced by turbulence caused by microinstabilities such as ion and electron-temperature-gradient (ITG/ETG) and trapped-electron-mode (TEM) instabilities, the latter ones known for being strongly influenced by collisions. Additionally, in stellarators, the neoclassical transport can be important in the core, and therefore investigation of the effects of collisions is an important field of study. Prior to this thesis, however, no gyrokinetic simulations retaining collisions had been performed in stellarator geometry. In this work, collisional effects were added to EUTERPE, a previously collisionless gyrokinetic code which utilizes the δ f method. To simulate the collisions, a pitch-angle scattering operator was employed, and its implementation was carried out following the methods proposed in [Takizuka & Abe 1977, Vernay Master's thesis 2008]. To test this implementation, the evolution of the distribution function in a homogeneous plasma was first simulated, where Legendre polynomials constitute eigenfunctions of the collision operator. Also, the solution of the Spitzer problem was reproduced for a cylinder and a tokamak. Both these tests showed that collisions were correctly implemented and that the code is suited for more complex simulations. As a next step, the code was used to calculate the neoclassical radial particle flux by neglecting any turbulent fluctuations in the distribution function and the electric field. Particle fluxes in the neoclassical analytical regimes were simulated for tokamak and stellarator (LHD) configurations. In addition to the comparison with analytical fluxes, a successful benchmark with the DKES code was presented for the tokamak case, which further validates the code for neoclassical simulations. In the final part of the work, the effects of collisions were investigated for slab and toroidal ITGs and TEMs in a tokamak configuration. The results show that collisions reduce the growth rate of slab ITGs in cylinder geometry, whereas they do not affect ITGs in a tokamak, which are mainly curvature-driven. However it is important to note that the pitch-angle scattering operator does not conserve momentum, which is most critical in the parallel direction. Therefore, the damping found in a cylinder could be the consequence of this missing feature and not a physical result [Dimits & Cohen 1994]. Nonetheless, the results are useful to determine whether the instability is mainly being driven by a slab or toroidal ITG mode. EUTERPE also has the feature of including kinetic electrons, which made simulations of TEMs with collisions possible. The combination of collisions and kinetic electrons made the numerical calculations extremely time-consuming, since the time step had to be small enough to resolve the fast electron motion. In contrast to the ITG results, it was observed that collisions are extremely important for TEMs in a tokamak, and in some special cases, depending on whether they were mainly driven by density or temperature gradients, collisions could even suppress the mode (in agreement with [Angioni et al. 2005, Connor et al. 2006]). In the case of stellarators it was found that ITGs are highly dependent on the device configuration. For LHD it was shown that collisions slightly reduce the growth rate of the instability, but for Wendelstein 7-X they do not affect it and the growth rate showed a similar trend with collisionality to that of the tokamak case. Collisions also tend to make the ballooning structure of the modes less pronounced.

The main objective of this research was to enhance the understanding of the inte¬ractions of bentonite with iron in the near field of a HLW-repository. One target was to investigate natural Fe-rich bentonites as a possible analogue. Another topic was to recognize the mineralogical interaction of bentonite with iron powder simulating the contact of bentonite with steel containers (thermodynamic approach). An additional objective was to explore the idea that bentonites have a specific dissolution potential (kinetic approach). In order to take the thermodynamic approach, compacted MX80 bentonite and Friedland clay were used as starting materials for clay/iron interaction experiments in per¬colation systems (Clay/Iron-ratio = 0.1). The natural processes were studied by examining a tropical wea¬thering profile of serpentiniz¬ed diabase from the Thanh Hoa province of Vietnam. The kinetic approach was taken by investigating a series of well characterized bentonites, 9 from API-standard series, 12 from the BGR-collection and 4 others, all of them saturated with deionized water (liquid/solid-ratio = 10/1) and NaCl 1N solution (liquid/solid-ratio = 4/1) for 30 days, followed by exposing the soft gels to mechanical agitation by overhead shaking corresponding to two energy levels (20 rpm and 60 rpm). XRD and TEM – EDX measurement were the major analytical techniques applied in this research, with FT-IR and XRF analyses as additional tools to characterizing the structure and composition of the smectites. Thermodynamic Approach MX80 bentonite and Friedland Clay clearly show that chemical and mineralogical changes have occured in the reaction products. They are exemplified by the neoformation of serpentine and chlorite in certain mixed layer phases. The smectite in the reaction products had also undergone changes especially in the constitution of the octahedral and tetrahedral sheets as well as in the interlayer space. These alterations were evident by the difference in key peak positions and ratios of XRD-patterns, and by TEM-investigations, as well as by different positions and intensities of FT-IR-bands of octahedral and tetrahedral features. The alteration was also seen in the bulk chemical composition data (XRF). MX80 bentonite and Friedland clay show various types and stages of alteration under different experimental conditions. The alteration can be described as “illitization” in open reaction systems and “smectitization” in closed reaction systems. The degree of alteration was controlled by the degree of chemical activities (ion strength, Fe- & Si-activity, con-centration). Higher reactivities give higher degrees of dissolution and release of Si from clay minerals. The oxidation of native iron (Fe0 → Fe2+) was recognized as the main driving force for dissolution, but also the oxidation of Fe2+ (Fe2+ → Fe3+) appeared to reverse an open to a closed reaction system by increased Si-pre¬cipitation. The thermodynamic modelling of C/I-experiments by Mingliang Xie (GRS mbH) verified identified mineralogical alterations in the reaction products. Generally, the contact with metallic iron caused a strong increase in dissolution potential. The reason for this is the reducing potential of oxidation of iron which raised pH to become alkaline and increase dissolution of Si from clay particles. The mineralogical transformations recognized in the experiments, such as the neoformation of serpentine and chlorite phases, were also observed in the tropical weathering profile of serpentinized diabase. The wellknown fast development of Fe-rich montmorillonite in alteration of ultramafic rocks (e.g., Schnellmann, 1964) was also identified by mineralogical investigation of the weather¬ing profile. This confirms that smectitization is linked with higher Fe-activities also in nature. Fe2+ was present in this system and during oxidation acted as driving force for alteration. The reduction potential of Fe-oxidation caused an increase of pH into alkaline conditions. Kinetic Approach The hypothesis that smectite clays have a specific dissolution potential emanated from the study. This would mean that high amounts of Fe and Mg in the octahedral sheet can accelerate alteration in agreement to what was early proposed by Cicel & Novak (1976). The larger ion diameter of Fe and Mg in comparison with Al may well be responsible for a higher sheet stress, which would facilitate dissolution of smectites. The idea proposed Kaufhold & Dohrmann (2008) concerning a mechanism that makes Ca- and Mg-cations in the interlayer space stabilize quasicrystals is also supported by the present study. The performed investigation indicate which mechanisms that serve to protect smectites from undergoing alteration and which promote alteration. Stable smectites, i.e. those with a low specific dissolution potential, were called here “Sleepers”, while fast reacting bentonites, which have a high specific dissolution potential, were termed “Sprinters”. Smectites react with different rates of reaction in laboratory experiments. As said, each smectite sample has its specific potential for dissolution and this potential is controlled by the composition of both the octahedral sheets and the interlayer space. Increasing amounts of octahedral Fe and Mg compared to octahedral Al increase the specific dissolution potential. This potential is also affected by the ion radius, implying that the larger ion radius of Fe and Mg compared to Al increases the mechanical sheet stresses in the octahedral sheet. In summary, this means that, the investigations have confirmed the initial hypothesis concerning the impact of the composition of the octahedral sheet. It results primarily from the pH during the formation of the smectite clay and therefore serves as a geological fingerprint. The Al-Fe ratio in the octahedral sheet influences the stability of the interlayer: A) Aloct > 1.4 and Feoct > 0.2 (per (OH)2 O10) favour delamination of quasicrystals. The swelling pressure increases by a co-volume process between the delaminated layers wiht higher numbers of quasicrystals for Na-dominant population of the interlayer space (Laird, 2006). The microstructural components including both small and large particles and parts of them have a very small ability to move and undergo free rotation. Such Na-montmorillonites are consider as stable phases and have only a low specific dissolution potential. They are „Sleepers“. B) Aloct > 1.4 and Feoct < 0.2 or Aloct < 1.4 and Feoct > 0.2 (per (OH)2 O10) promote demixing of monovalent and divalent interlayer cations (Laird, 2006). In the case of Ca and Mg-dominant interlayers, quasicrystal can break Na-bearing interlayers and help to maintain the quasicrystal structure. Such Ca and Mg-mont¬morillonites can be also be taken as „Sleepers“ because of their low specific dissolution potential. Depending on the octahedral composition, certain cations in the inter¬layer can stabilize bentonites against mineralogical changes. Montmorillonites stabilized by high concentration of Na-cations were classified as belonging to category A, while montmorillonites stabilized by high Ca, Mg-cations in the interlayer sheet were grouped in category B. The classification of a smec¬tite into the categories A or B defined above can be best achieved by IR analyses that yield useful chemical information concerning the composition of the octahedral sheets. Smectites with Na as stabilizing interlayer cation (group A) have shown δAlAlOH-bands with increasing wavenumbers for increasing octahedral Al in FT-IR spectra. The other reaction type of smectite, with Ca, Mg-cations in the interlayers (group B), is characterized by a decreasing octahedral Al-amount for increasing wavenumbers of δAlAlOH-bands in such spectra. Also the FT-IR δAlFeOH-bands are different in the two reaction types of smectite. Increasing octahedral Fe-amounts were mirrored by decreasing wavenumbers of δAlFeOH-bands. However, smectites of group B do contain higher Fe-amounts for the same wavenumber than smectites of group A. Expected alteration of bentonite close and far from a steel canister In the early interaction of smectite-rich clay – the “buffer” - and steel, the system behaves as being chemically closed. Within the clay barrier, Si will be dissolved from clay mineral particles in accordance with its specific dis¬solution potential. The dissolved Si can stay by contributing neoformation of mont¬morillonite layers in mixed layer phases. The interlayer charge decreases by substitution of Mg by Al, which leads to an increase in the swelling pressure. Also minor Si-precipitation may occur if not all the dissolved Si is used up by the neoformed montmorillonite layers. Such precipitation of Si will cause cementation of some quasicrystals and lead to a reduction in porosity. Enhanced temperature and additional Fe-activity, representing an increased reduction potential, increases notably the amount of dissolved Si at the interface between bentonite and steel canister, and as a consequence there will be significant precipitation of Si. The resulting cementation of quasicrystals is ac¬com¬panied also by their collapse which induces broadening of pores. This caused the channel-like migration of infiltrating solutions and switches the system into an open one. Thermodynamic predictions indicate that “illite” will be generated close to the steel canister (via “illitization”) and kaolinite or pyrophyllite to be formed farther away (via smectitization). The “illitization” process results in higher interlayer charges and lower swelling pressures. In contrast, the formation of smectite reduces interlayer charges and promotes higher swelling pressures. At the end of the thermodynamic evolution, the swelling pressure will drop also far from the canister because kaolinite and pyrophyllite are non-swelling minerals. In both cases, the applications of so-called “Sleeper”-bentonites are required to slow the reaction progress. For designers of the engineered barriers in a repository, i.e. the canister and the “buffer” clay, some basic rules are recommend on the basis of the present study. Thus, the presence of native Fe or Fe2+-cations in the clay or in accessory minerals in it, or emanating from the canisters, will speed up the reaction process and make it extensive. Likewise, use of Fe-poor “buffer” clay, representing “Sleepers”-type are suitable for slowing down the reaction. Copper as canister material, and very dense Na-rich montmorillonite of group A as “buffer” seem to be ideal rather than steel/iron and less dense Ca-saturated clay.

In the framework of the current work has been the plasma initiated and surface catalysed species conversion studied in low pressure and atmospheric plasmas. The aim of the work is to improve the understanding of the internal processes in order to increase the energy efficiency as well as the selectivity of the reaction products of future plasma devices. Beside many technical applications of plasmas, air purification shows great potential. Over the last decades, plasma based pollution control has proofed its ability to remove harmful contaminants or annoying odours from an air stream. However, the energy efficiency and the selectivity of the products are a remaining challenge. Motivated by these issues, a multi stage packed-bed reactor has been used to remove admixed ethylene and toluene from an air stream. It has been found that the maximum toluene destruction has been 60%, whereas ethylene has been nearly completely removed. The specific energy β has been between 120 and 1600 JL-1. Fourier Transform Infrared spectroscopy, FTIR spectroscopy, has been used to identify and quantify the species H2O, CO2, CO, O3, HNO3, HCN, CH2O, CH2O2, N2O and NO2. However, none of these experiments led to the detection of NO. The embedment of packing material into a plasma volume leads to increased surface effects. In order to study them, the inner side of a tube reactor, made of Pyrex, served as the surface under study and has been exposed to a rf plasma for 1h. The surface effects of the plasma treatment have been investigated indirectly by studying the oxidation of NO into NO2. After the plasma exposure, the reactor has been evacuated and filled with a gas mixture of 1% NO in N2 / Ar. Both species have been measured using quantum cascade laser absorption spectroscopy, QCLAS. It has been found that, using oxygen containing plasmas, the NO concentration decreased whereas the NO2 concentration increased. Therefore, oxygen containing plasmas are able to deposit oxygen on the surface. The filling with NO leads to the oxidation via the Eley-Rideal mechanism. A simplified model calculation supports these assumptions. For a more comfortable application of the QCLAS, a compact multi channel spectrometer has been developed, TRIPLE Q. It combines the high time resolution with the possibility to measure the concentration of at least three infrared active species simultaneously. Due to the high time resolution, a huge number of spectra have to be analysed. In order to calculate absolute number densities, an algorithm has been developed which automatically treats typical phenomena like pulse jitter, rapid passage effect or variations of the intensity of the laser pulses. The gas temperature is an important parameter in plasma physics. Using the TRIPLE Q system, the gas temperature has been determined for pulsed dc plasmas. For this case, NO has been used as a probe gas. From the spectra, the temperature has been calculated using the line ratio method. The relative intensity of the absorption structures of NO at 1900.5cm-1 and 1900.08cm-1 depend on the temperature. Therefore, the ratio has been used to calculate the gas temperature with a time resolution in the μs range. Vibrationally excited nitrogen can be an energy reservoir that plays an important role in plasma chemistry. In N2 / N2O plasmas, vibrationally excited N2 can undergo relaxation via a resonant vibration vibration coupling between vibrationally excited N2 and N2O. Due to such an efficient energy transfer, the method allows one to study the relaxation of vibrationally excited N2. Using this method, molecules, which are not infrared active, can be monitored. This approach has extended the field of scientific and commercial applications of the QCLAS.