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Microbial infections can be either caused by a single species or complex multi-species consortia. One of the most prominent opportunistic human pathogens leading to mono- or mixed-species infections is the Gram-negative bacterium Pseudomonas aeruginosa. Understanding the molecular basis of its adaptation to infection-related stresses is an essential prerequisite for the prevention and treatment of P. aeruginosa infections. We therefore employed state-of-the-art proteomics approaches to elucidate the molecular adaptation mechanisms of P. aeruginosa to infection-related conditions. Moreover, structure, function and interaction of complex microbial consortia containing P. aeruginosa and causing catheter-associated urinary tract infections were investigated by metaproteomics analyses. Our investigations revealed that the adaptation of P. aeruginosa during infection is either based on gene expression changes caused by environmental signal integration or by gene mutations leading to a selective advantage in a particular host environment. In study I, investigating the proteome response of P. aeruginosa biofilms to the clinical relevant antibiotic ciprofloxacin, global changes in the protein profile were observed. Ciprofloxacin induced the expression of proteins involved in the Lex-induced SOS-response, drug efflux pumps and gene products of the ciprofloxacin-responsive prophage cluster and repressed the expression of porins and DNA-binding proteins. In study II the transcriptome and proteome of two clonal P. aeruginosa lineages during long-term colonization of cystic fibrosis (CF) patient’s lungs were analyzed. Point mutations in global regulator genes, i.e. retS, gacS, and gacA, were identified by genomic sequencing. Inactivation of RetS, found two years after the initial colonization, induced the expression of genes involved in chronic infections and coding for the type 6-secretion system (T6SS). Additional mutations in the GacS/GacA two-component regulatory system (TCS) were found to repress the expression of T6SS proteins and to induce the expression of proteins belonging to the type 3-secretion system (T3SS). In study III we elucidated the niche-specific adaptation of P. aeruginosa isolates from different infection sites by investigating their protein expression patterns and glucose metabolic fluxes. We could show that isolates from the urinary tract express a higher amount of proteins involved in the acquisition of micronutrients (i.e. iron) and carbohydrates compared to isolates from the CF lung. In study IV 16S rDNA sequencing and metaproteomics were employed to demonstrate that the investigated CAUTI-related biofilms consisted of two to five different species with one or two species dominating the mixed community. Following this line of research, we investigated in study V structure and function of a biofilm of a long-term catheterized patient, which was predominantly composed of P. aeruginosa and Morganella morganii, but also contained a minor proportion of the obligate anaerobe Bacteroides sp.. The comparison of in vivo and in vitro protein expression profiles of P. aeruginosa and M. morganii indicated that iron and carbohydrates are the major growth-limiting factors in the bladder. These results indicate different nutritional strategies of the two pathogens in the bladder environment. A comparison of urinary protein profiles of healthy persons and catheterized patients suggested that the human innate immune system is induced by CAUTIs. Moreover, numerous proteins involved in nutritional immunity, e.g. iron-, calcium- and magnesium-binding proteins, were found to be more abundant in the urine of catheterized patients. A follow-up (meta)proteomics study (study VI) aiming at the elucidation of interspecies interactions during multi-species infections indicated that the urease-positive uropathogen Proteus mirabilis induces the precipitation of metal ions by urine alkalization and thereby limits the availability of these important micronutrients for other co-infecting bacteria. This limitation seems to be sensed by the P. aeruginosa PhoP-PhoQ two-component system (TCS) leading to an increased resistance to antimicrobial peptides and biofilm-forming capacity of the pathogen. Also during co-cultivation of P. aeruginosa with Staphylococcus aureus a slight increase in the expression of the PhoP-PhoQ TCS and the alkaline protease could be observed (study VII). In study VIII a combined metagenomics and metaproteomics approach was employed to investigate structure and function of the lichen Lobaria pulmonaria, a complex consortium consisting of a fungus, an algal partner, cyanobacteria, and a highly diverse bacterial microbiome. The results presented in this work contribute to a better understanding of the manifold and complex bacterial adaptation mechanisms to infection-related and environmental stress and thereby foster the development of novel treatment and prevention strategies.
Background: Robotic-assisted laparoscopy (RAL) is being widely accepted in the field of urology as a replacement for conventional laparoscopy (CL). Nevertheless, the process of its integration in clinical routines has been rather spontaneous. Objective: To determine the prevalence of robotic systems (RS) in urological clinics in Germany, Austria and Switzerland, the acceptance of RAL among urologists as a replacement for CL and its current use for 25 different urological indications. Materials and Methods: To elucidate the practice patterns of RAL, a survey at hospitals in Germany, Austria and Switzerland was conducted. All surgically active urology departments in Germany (303), Austria (37) and Switzerland (84) received a questionnaire with questions related to the one-year period prior to the survey. Results: The response rate was 63%. Among the participants, 43% were universities, 45% were tertiary care centres, and 8% were secondary care hospitals. A total of 60 RS (Germany 35, Austria 8, Switzerland 17) were available, and the majority (68%) were operated under public ownership. The perception of RAL and the anticipated superiority of RAL significantly differed between robotic and non-robotic surgeons. For only two urologic indications were more than 50% of the procedures performed using RAL: pyeloplasty (58%) and transperitoneal radical prostatectomy (75%). On average, 35% of robotic surgeons and only 14% of non-robotic surgeons anticipated RAL superiority in some of the 25 indications. Conclusions: This survey provides a detailed insight into RAL implementation in Germany, Austria and Switzerland. RAL is currently limited to a few urological indications with a small number of high-volume robotic centres. These results might suggest that a saturation of clinics using RS has been achieved but that the existing robotic capacities are being utilized ineffectively. The possible reasons for this finding are discussed, and certain strategies to solve these problems are offered.
Background: Pancreatic ductal adenocarcinoma (PDAC) is characterised by an extremely poor overall survival (OS) compared to other solid tumours. As the incidence of the disease is rising and the treatment options are limited, PDAC is projected to be the 2nd leading cause of cancer-related deaths in the United States by 2030. A majority of patients are not eligible for curative resection at the time of diagnosis, and those that are resected will often relapse within the first few years after surgery. Summary: Until recently, the nucleoside analogue gemcitabine has been the standard of care for patients with non-resectable PDAC with only marginal effects on OS. In 2011, the gemcitabine-free FOLFIRINOX regimen (folinic acid, fluorouracil, irinotecan and oxaliplatin) showed a significant survival advantage for patients with metastatic PDAC in a phase III trial. In 2013, the Metastatic Pancreatic Adenocarcinoma Trial phase III trial with nano-formulated albumin-bound paclitaxel (nab-paclitaxel) in combination with gemcitabine also resulted in a significant survival extension compared to gemcitabine monotherapy. However, both intensified therapy regimens show a broad spectrum of side effects and patients need to be carefully selected for the most appropriate protocol. Key Message: In this study, recent advances in the chemotherapeutic options available to treat metastatic PDAC and their implications for today's treatment choices are reviewed.
Although End Stage Renal Disease (ESRD) is a disease of increasing epidemiological relevance very little is known about the cost of providing the respective dialysis services in Tanzania. This study analyses the cost of outpatient dialysis at Muhimbili National Hospital (MNH) in Tanzania in the year 2014 in order to address the question weather or not dialysis treatment should be a priority intervention in a poor resource country like Tanzania. Cost analyses were performed based on the provider’s perspective including only direct costs of dialysis treatment. Cost of drugs and consumables were obtained from the price list of Medical Stores Department in Tanzania. Overhead were collected from the respective departments and allocated to the final cost centres through step down approach. The results indicates that MNH performs on average 442 hemodialyses per month (34 patients, with three sessions per week) with a personnel placement of 20 nurses, four nephrologists, eight registrars, one nutritionist, two biomedical engineers, four health attendants and nine dialysis machines. The respective average unit cost per haemodialysis is 175.91 US$. Consequently, an average patient requiring three dialyses per week (i.e. 156 dialyses per year) will cause annual costs of 27,441.95 US$. The annual cost of dialysis is enormous for a least developed country like Tanzania where resources and technology are rather limited. Infectious diseases (such as malaria and tuberculosis) are the major health problems. Therefore, from the economic point of view, it seems rational to allocate health care budgets towards diseases that are curable, have higher cost- effectiveness and cater for the majority of the population. However, before a final decision on allocation of budget towards dialysis is made, all efforts that could improve technical efficiency and reduce the costs of materials in Tanzania must be invested. For instance, reducing the nursing time per dialysis.
A slice is an intersection of a hyperplane and a self-similar set. The main purpose of this work is the mathematical description of slices. A suitable tool to describe slices are branching dynamical systems. Such systems are a generalisation of ordinary discrete dynamical systems for multivalued maps. Simple examples are systems arising from Bernoulli convolutions and beta-representations. The connection between orbits of branching dynamical systems and slices is demsonstrated and conditions are derived under which the geometry of a slice can be computed. A number of interesting 2-d and 3-d slices through 3-d and 4-d fractals is discussed.
All-embracing human activities have transformed one-third to one-half of the Earth’s land surface. There is a strong correlation of human well-being with ecosystem function, including poverty alleviation programs as well as enhancements of the health sector. To assess and evaluate the progress and outcome of initiatives stringent periodic observation is necessary. The presented approach combines the strengths of remote sensing and GIS analysis with social research applications. The Bach Ma National Park as an area under investigation was designated as protected area in 1991 and extended in 2008. The national park is uninhabited, but in the surrounding buffer zones approximately 62000 to 79000 people live in rural areas and in mostly impoverished conditions. The comprehensive nature conservation efforts of the Vietnamese Government during the last two decades has led to growing forest coverage of both plantation and natural forests. Nevertheless, the decreasing biodiversity and ongoing illegal logging and hunting activities in the national park are seen as major threats to conservation initiatives in the future. The remote sensing component consists of an analysis of a time series of Landsat images with seven steps ranging from 1973 to 2010. The resulting land cover analysis had 13 different classes. The accuracy assessment revealed an overall accuracy ranging from 84 to 90%. The basis for the second monitoring component was the Landsat images. A total of 25 different landscape metrics on the landscape, class, and patch level were calculated by FRAGSTATS. The third monitoring component is itself divided into two parts. This part consists of a qualitative social research study with 26 expert interviews. The second part consists of 61 standardized questionnaires and an evaluation by SPSS. The assessment reveals a more or less stable forest cover, but with a considerable degradation process during the last four decades. Urban areas outside of the national park have increased in size considerably. For dense and medium forest patches an increasing fragmentation and isolation of patches was observed. Patches of natural forests and habitats of thousands of species have declined dramatically, a trend that is related to a decreasing core area characterised by its undisturbed conditions. The Landsat images and landscape metrics reveal the major differences between the national park and surrounding areas. Despite extensive alterations near the border, remaining forest patches in the national park are still bigger and less fragmented. Nevertheless, the third monitoring component revealed undiscovered changes in the forest beyond the possibilities of used images and metrics. It includes illegal logging and hunting activities. Non-timber forest products are similar to faunistic species collected for both the subsistence of the local residents and associated markets as important sources of income. Based on this bisection, local residents as well as certain strangers are responsible for the activities in the forest. The plan of national park management is to intensify existing monitoring and patrolling in the forest to limit the exploitation and impact in relevant zones. Furthermore, the importance of a network of protected areas has attracted increasing attention. The assessment of the questionnaires reveals that deforestation and also reforestation were the key aspects of historical land cover change. Additionally, for the local residents the conversion of forests into arable land as income alternative is of major importance. Capacity development is not only one priority of the Bach Ma management but also of the international community for all of Vietnam. The tourism industry, one of the most promising opportunities of recent years, stands to support both national park management as well as the local residents. For local residents the extraction of non-timber forest products is an essential portion of the income. The current pilot policy 126/QD-TTg in the extension zone of the national park and research on an appropriate sharing mechanism is of the utmost importance. The established and presented monitoring components are cost-effective and can be used to regularly assess the land cover change of a protected area. They can be implemented together or individually into existing monitoring schemes. A smart combination of pre-existing datasets is necessary to overcome the inconsequential amount of money for monitoring procedures. Supplemented by socio-economic monitoring and the demands as well as impacts of human activity need to be integrated. These extensive requirements for prospective monitoring are only feasible with comprehensive and reliable collaborations.
Compared to gun control legislation in Germany, which is supposed to be one of the most stringent in Europe, gun control legislation in Vietnam is by far stricter. Private possession of guns is not possible in Vietnam. One key point in the German weapons act is the allowance for certain facilitations for airguns that impart kinetic energy of less than 7.5 J to the projectile. These airguns are freely available for purchase by persons 18 years of age or older. The 7.5 J limit is applied to airguns without further efinition of projectile characteristics like projectile head, projectile shape or projectile mass. In the course of a possible relaxation of gun control and facilitation of private gun ownership (especially of airguns) in Vietnam, an implementation of a kinetic energy limit, similar to the German 7.5 J limit, is conceivable. It was the aim of this cumulative doctoral thesis to investigate if this energy limit was a sufficient threshold to estimate the dangerousness of a weapon or projectile, especially in cases where the characteristics of the projectiles are fundamentally different from the “standard” projectiles which were basis for the implementation of this energy threshold in the German weapons act in 1968. The first study investigated basic ballistic parameters of plastic-sleeved composite projectiles in comparison to standard diabolo pellets. Although overall results were inconsistent, for some projectile–weapon combinations (particularly for spring-piston air guns), a significant change of the kinetic energy (− 53 up to + 48 %) to the reference projectile was observed. For some projectile types the legal limit of 7.5 J was exceeded by far. The second study focused on an uncommon discarding sabot airgun projectile (SUSSEX SABO). It was demonstrated, that the sabot principle works properly in high power airguns (E > 17 J), but separation of the core projectile from the sabot cup was also observed in mid- (E = 12.5 J) and low-energy (E < 7.5 J) airguns. While muzzle velocity and kinetic energy values of discarded sabot projectiles are comparable to conventional diabolo pellets, energy density (ED) and penetration capacity are significantly higher. Finally, the ballistic performance of a carbon dioxide-actuated arrow pistol (Arcus Arrowstar) was investigated. Compared to conventional diabolo pellets of a similar kinetic energy level, the penetration depth of this arrow projectile was increased by approximately 35 %. This high penetration capacity was mainly caused by the uncommon projectile characteristics (high cross-sectional density q and pointed arrow head). The findings of this work reveal that special projectile types, like the plastic-sleeved composite pellets, might substantially increase the muzzle energy of airguns. Other uncommon projectile types (like the SUSSEX SABO projectile or the Arcus Arrowstar projectile) exert a higher penetration capacity whereas kinetic energy is similar to standard diabolo pellets and is still beneath the legal limit. For these uncommon projectile types, the 7.5 J limit implemented in the German weapons act is not a sufficient threshold. As demonstrated, next to kinetic energy E and energy density ED, the characteristics of the projectile influence their ballistic parameters. So it is strongly recommended to specify legal kinetic energy limits in gun control legislation in greater detail. The design characteristics of the projectiles (cross-sectional density q and design of the projectile head) should be appropriately taken into consideration.
Telemedicine at the Emergency Site – Evaluated by emergency team members in simulated scenarios
(2015)
The hypothesis of this study states that emergency medicine can benefit from telemedicine, whenever paramedics at a remote emergency site request consultation or mentoring by a distant emergency doctor. The hypothesis was semi-qualitatively evaluated in accordance with the protocol of the EU project in the setting of a medical simulation centre. Paramedics encountered simulated standardized emergency case scenarios, connected for teleconsultation and telementoring with emergency doctors by video and audio link through a newly developed real-time HD-video system called LiveCity camera. Paramedics and emergency doctors regarded the simulated scenarios as realistic and relevant and took the simulation seriously. Thus,the following conclusions can be drawn: 1.) Emergency team members encounter situations at the emergency site, in which they would like to get help by a more experienced colleague, especially help with diagnostics and treatment. 2.) The telemedical contact to an emergency doctor makes paramedics feel confirmed in their work, more secure, even in legal aspects. Paramedics do not feel controlled by telemedicine or like a puppet on a string. Their relationship to the patient is not mainly deranged or interfered by the doctor and their course of action is not mainly disrupted. The tele-emergency doctors do not feel like puppet masters and continue feeling as doctors and do not perceive themselves as interferer within the emergency team. 3.) Emergency team members call for a telemedical system providing transmission of vital signs as well as audio- and video-connection. 4.) The LiveCity camera is an effective telemedical tool. The audio quality is good and the orientation on the screen is easy. Paramedics state, that filming the emergency site is easy, does not restrict the field of vision and paramedics can communicate the emergency doctors everything they want to show and tell. Thus the emergency doctors get additional information. While the LiveCity camera is mostly perceived as not too heavy, the LiveCity camera is not easy to operate, very failure-prone and can derange the communication among team members at the emergency site. Nevertheless, the LiveCity camera is not perceived as an additional burden. 5.) Telemedicine is predominantly and largely appreciated by the members of the emergency team. Connecting the tele-emergency doctor to the remote paramedics leads to a perceived faster start of the therapy and is considered as helpful, improving the situation and the quality of patient care. The adherence to medical guidelines and therefore the quality increased, when the paramedics were connected to an emergency doctor through the telemedicine connection. In general, the quality of diagnostics, the correctness of diagnosis and the quality of therapy were rated higher. The majority of paramedics would call a tele-emergency doctor in cases, they wouldn´t normally activate medical support. The emergency team members largely agree in perceiving the tele-emergency doctor system as useful, and they can imagine, working in a tele-emergency system. As a conclusion, the general hypothesis of this study is mainly and in many items supported: Emergency medicine benefits from telemedical support via video- and audio link as studied here with a newly developed real-time HD-video system called LiveCity camera, whenever paramedics at a remote emergency site request consultation or mentoring by a distant emergency doctor.
Today the process of improving technology and software allows to create, save and explore massive data sets in little time. "Big Data" are everywhere such as in social networks, meteorology, customers’ behaviour – and in biology. The Omics research field, standing for the organism-wide data exploration and analysis, is an example of biological research that has to deal with "Big Data" challenges. Possible challenges are for instance effcient storage and cataloguing of the data sets and finally the qualitative analysis and exploration of the information. In the last decade largescale genome-wide association studies and high-throughput techniques became more effcient, more profitable and less expensive. As a consequence of this rapid development, it is easier to gather massive amounts of genomic and proteomic data. However, these data need to get evaluated, analysed and explored. Typical questions that arise in this context include: which genes are active under sever al physical states, which proteins and metabolites are available, which organisms or cell types are similar or different in their enzymes’or genes’ behaviour. For this reason and because a scientist of any "Big Data" research field wants to see the data, there is an increasing need of clear, intuitively understandable and recognizable visualization to explore the data and confirm thesis. One way to get an overview of the data sets is to cluster it. Taxonomic trees and functional classification schemes are hierarchical structures used by biologists to organize the available biological knowledge in a systematic and computer readable way (such as KEGG, GO and FUNCAT). For example, proteins and genes could be clustered according to their function in an organism. These hierarchies tend to be rather complex, and many comprise thousands of biological entities. One approach for a space-filling visualization of these hierarchical structured data sets is a treemap. Existing algorithms for producing treemaps struggle with large data sets and have several other problems. This thesis addresses some of these problems and is structured as follows. After a short review of the basic concepts from graph theory some commonly used types of treemaps and a classification of treemaps according to information visualization aspects is presented in the first chapter of this thesis. The second chapter of this thesis provides several methods to improve treemap constructions. In certain applications the researcher wants to know, how the entities in a hierarchical structure are related to each other (such as enzymes in a metabolic pathway). Therefore in the 3 third chapter of this thesis, the focus is on the construction of a suitable layout overlaying an existing treemap. This gives rise to optimization problems on geometric graphs. In addition, from a practical point of view, options for enhancing the display of the computed layout are explored to help the user perform typical tasks in this context more effciently. One important aspect of the problems on geometric graphs considered in the third chapter of the thesis is that crossings of edges in a network structure are to be minimized while certain other properties such as connectedness are maintained. Motivated by this, in the fourth chapter of this thesis, related combinatorial and computational problems are explored from a more theoretical point of view. In particular some light is shed on properties of crossing-free spanning trees in geometric graphs.
The present work examines the decision-making process of clinicians and managers in terms of pricing. This dissertation attempts to make often unconscious processes in both the clinical and economic areas more transparent. Due to this increase in transparency and an illustration of the overall decision-making process, a prioritization of the decision-drivers is enabled. Similarily, overall decision-making on stakeholder level is improved. The findings of this work are based on a dual sample: The paper primarily combines qualitative expert discussions in the clinical field with a quantitative manager survey. Therefore, the advancement of knowledge is specifically furthered in terms of pricing decision-making, as well as specific economic and thematic aspects. These form the basis for clinical/managerial decision-making. Since such specific understanding enables better acting and reacting during the negotiation processs, clients of medical device companies (eg clinics) could additionally benefit from improved understanding. Although the focus of this work rests on the clinical area, this paper also examines how companies of the medical technology industry could offer more economic medical products by means of using the instrument of pricing. Based on an interdisciplinary approach and a collection of primary data, this work also discusses a solution approach for corporate/entrepreneurial inefficiencies discovered in this paper. A final conceptual model illustrates different value allocations from both stakeholder groups (clinicians vs. managers). With regard to the research focus, the conceptual model is understood as a holistic solution for recognizing and correcting business gaps in the areas of knowledge transfer, innovation, knowledge of markets and standardization of processes.
Next Generation Sequencing (NGS)-technologies developed very fast in recent years and is used widely in current research areas. The aim of this study was to use NGS (i) for the identification of pathogens in outbreaks and (ii) for the identification of virulence-relevant sequencepolymorphisms when comparing whole genome sequences. Therefore, a previous developed workflow was used to identify a new virus of the family Bornaviridae. The generation of whole genome sequences elucidated the molecular epidemiological connection of infection of variegated squirrels (Sciurus variegatoides) and three human cases of fatal encephalitis. By generating the whole genome sequence of a Porcine Epidemic Diarrhea Virus (PEDV) in Germany it was possible to find difference compared to circulating high virulent strains in the USA. This led to potential virulence marker to distinguish strain in the USA and Germany. Connections between sequence variation and virulence were further investigated for the bovine viral diarrhea virus 2c (BVDV-2c), cowpox viruses (CPXV) and classical swine fever virus (CSFV). Here, for a highly virulent BVDV-2c strain a mixture of different genome structure variants could be found. The majority of these genomes harbors a duplication within the p7/NS2 coding region and might cause a high virulence. For CPXV virus isolated of different hosts were analyzed and a correlation between genome sequence and the A-type inclusion body phenotype could be found. Furthermore, several deletion/insertion events were detected which might influence the virulence of these strains. Finally, the virus population of CSFV strains in pigs was characterized. However, the population of the inoculum as well as of acute-lethal and chronically infected animals gave no indication that the virus itself causes the different types of disease outcome. In conclusion, this thesis shows the great potential of NGS for virus identification and characterization. Furthermore, it makes the identification of potential virulence marker possible which subsequently can be analyzed by reverse genetics.
The main issue of this thesis was the investigation of dusty plasmas in magnetic fields. We made use of spherical paramagnetic as well as non-magnetic plastic particles in the micrometer range, so-called dust particles. The particles were then trapped in the sheath region of the driven lower electrode of an rf discharge. The plasma chamber was surrounded by coils to apply a horizontal magnetic field with field strengths of up to B=50mT at the particles’ position. In this configuration the sheath electric field and the external magnetic field were perpendicular to each other. Only the electrons could be magnetized but this leads to several forces acting on the dust particles. In some aspects the dust clusters with the magnetic particles show a behavior that is in complete contrast to those consisting of the standard non-magnetic plastic particles. Both types of particles have in common that the dust clusters were found to move either towards the positive or negative ExB-direction as a reaction to the magnetic field. Whether the positive or negative direction was preferred depended on the experimental conditions. The forces that lead to this transport are plasma-based forces induced by the magnetic field. These investigations were performed on two-dimensional horizontal particle systems. Vertically aligned dust particles due to the ion focus interaction have also been studied to determine the influence of horizontal magnetic fields on the stability of such dust pairs. Under certain conditions the vertical alignment can be broken up by the magnetic field. Some additional experiments on the interaction of non-magnetic dust particles in a plasma with UV irradiation were performed, but a significant decrease of dust charge due to a photoelectric effect was not detected. In summary, even relatively weak horizontal magnetic fields have a strong influence on dust particle systems.
In the last decade a new domain has developed in plasma physics: plasma medicine. Despite the successes that have already been achieved in this exciting new field, the interaction of plasmas with “biological materials” is not yet fully understood. Further investigations in particular with respect to the properties of the applied plasmas sources are therefore essential in order to decode this complex interaction process. Currently, a great variety of different discharge types are used in plasma medical investigation which are generally are operated in noble gases like helium and argon or with dry air. In the present work, the main focuses is on the diagnostics of reactive oxygen and nitrogen species (RONS) resulting from the plasma chemistry of an argon radio-frequency (RF) atmospheric pressure plasma jet (APPJ) and its interaction with the ambient atmosphere. To conduct this study, a commercially available plasma device, so-called kinpen is used due to its technical development maturity and its accessibility on the market. As a method of choice, diagnostic techniques are based on optical spectroscopy known to be a reliable tool to investigate plasmas. Consequently, three complementary optical laser diagnostics, namely quantum cascade laser absorption spectroscopy (QCLAS), laser induced fluorescence (LIF) and planar single shot LIF (PLIF), have been successfully applied to the plasma jet itself or its effluent. All of these diagnostics offer a high species selectivity and an excellent spatial and temporal resolution. They are used in this work for i) the characterization of the plasma chemical dynamics with respect to the generation of biological active RONS – in particular for the case of N2 and O2 admixtures. ii) the measurement of the NO density profile in the plasma effluent iii) the investigation of the flow characteristics of the neutral gas component (laminar vs. turbulent) and its influence on the plasma chemistry. Numerical analysis have been carried out in collaboration with PLASMANT (University of Antwerp) via kinetic simulations of the entire plasma chemistry. Expectingly, atomic oxygen (O) and nitric oxide (NO) turn out to be precursors of ozone (O3) and nitric dioxide (NO2). However, it was intriguing to unveil that atomic oxygen and nitrogen metastable (N2(A)) play together a key part --as intermediate species-- in the generation of more stable RONS, e.g. NO. The absolute density of NO space resolved was measured by LIF and absolutely calibrated molecular beam mass spectrometer. LIF was used to determine relative density of OH radical in the plasma plume. 2D-LIF was used to investigate the gas flow pattern with OH as a flow tracer. The results are discussed in details and show different operating mode of the jet, e.g. laminar or turbulent and that the plasma influences these regimes. The first detection and relative measurement by LIF of nitrogen metastable (N2(A)) produced by an argon APPJ is also shortly reported in this work. The outcome of this thesis will bring new insights in the field of argon APPJs chemistry and its interaction with the ambient atmosphere which can be valuable to support plasma modelling and to consider for the applications in plasma medicine.
Dwarf spiders (Linyphiidae, Erigoninae) are especially suitable for sexual selection research as many of them exhibit sexual dimorphism, with males possessing modified prosomata. In those species that have been investigated in detail the modified structures are equipped with a glandular tissue that produces secretions, which the females contact and take up during courtship/copulation. The time of secretion release, and refilling of the reservoirs was analysed on an ultrastructural level in male Oedothorax retusus. The results suggest that the main function of the secretions is gustatorial courtship and not the emission of volatile pheromones for mate attraction. Mating decisions and reproductive success are influenced by secondary sexual traits that evolved under sexual selection. However, an individual´s nutritional status is also important for mate choice. Since spiders are regularly exposed to limited prey availability, adult feeding status can be considered an important component of spider mating behaviour. In order to test for the effects of dietary restriction, females of the closely related species O. retusus and O. apicatus were subject to a short period of food shortage. The effects of low- (LD) vs. high-diet (HD) treatment on courtship, mating probability and behaviour, and reproduction were analysed. We found that short phases of diet restriction as adults have a high impact on copulation and reproduction in the two dwarf spider species. Whenever females mate with more than one male, and sperm is stored prior to fertilization, males may suffer from sperm competition. Mating plugs that block the female genital openings after mating are a male strategy to avoid sperm competition. Although mating plugs occur in many species, their function and origin has hardly been investigated. O. retusus males transfer amorphous material onto the female genitalia during mating. We investigated the location of plug production using x-ray microtomography (μCT) as well as light and transmission electron microscopy (TEM). Furthermore, we asked whether males are limited in the production of the amorphous plug material in successive matings. The plug material is produced in a gland inside the male pedipalp and stored close to the blind end of the sperm storage compartment. The size of the first plug a male produced significantly influenced the size of subsequent plugs. Obviously, males do not possess unlimited amounts of plug material in a certain period, which may severely limit their ability to secure paternity through subsequent mating plugs. Even though mating plugs seem to be an obvious means to secure paternity, their potential in securing paternity depends on their mechanical efficacy and persistence. Consequently, the influence of the size of the plug material (mating duration as a proxy) and the age of the mating plug (time interval between successive copulations) on its efficacy was investigated. Small and fresh plugs were least effective, whereas large plugs were highly effective. We were able to show that mating plugs in O. retusus are a powerful mechanical safeguard whose efficacy varies with plug size and age. Genitalia in animals with internal fertilization are complex, species-specific, and underlie rapid evolution. In spiders, male and female genitalia are paired, and have to interact during mating, which results in an even higher complexity. Pedipalps (transformed pair of legs) in male spiders are used as secondary sperm transfer organs that are not directly connected to the gonads. Due to the high complexity of male pedipalps, it has been taken for granted that pedipalps are side specific and cannot be used flexibly into either female copulatory opening. We investigated potential flexible pedipalp use in O. retusus. Our findings demonstrate a flexible insertion mode in a dwarf spider with complex pedipalps but relatively simple female genitalia. Our findings corroborate sexual selection as the selective regime for the evolution of complex and diverse genitalia. The results of this thesis show how complex sexual selection acts in the dwarf spiders O. retusus and O. apicatus. It shapes the evolution of male and female genitalia, affects mate choice (pre- and postcopulatory), mating behaviour, and influences mating success and reproduction. All these factors and traits affect an individual´s evolutionary fitness, and their interactions help to understand how sexual selection acts.
The immune system of all vertebrates primarily is responsible to maintain the organisms homeostasis by either eliminating neoplastic or altered body cells and to protect against foreign invaders (viruses, bacteria, fungi, parasites) (Murphy 2012). It is a highly regulated network of innate and adaptive mechanisms between humoral factors and leukocytes. The successful elimination or protection is crucially based on differentiation of self from non-self. Pathogens and altered body cells are recognized by different receptor complexes on immune cells. Expressed pathogen- or danger-associated molecular patterns (PAMPs or DAMPs, respectively) are bound by pattern recognition receptors (PRR) (Takeuchi and Akira 2010). Missing major histocompatibility (MHC) class I molecules or non-self (e.g. allogeneic or xenogeneic cells) MHC are recognized by natural killer cell receptors (Fischer, Koppang and Nakanishi 2013, Raulet 2006). Foreign non-self peptides are presented through MHC class I (intracellular) or through MHC class II (extracellular) to B- cell or T cell receptor complexes. This initial activation is regulated by humoral factors or cellular interactions (receptor-ligand interactions) resulting in the activation, proliferation and effector function within an immune response. Some of the cellular receptors are permanently expressed on all leukocytes on a high level (MHC class I), whereas others only are expressed during certain developmental or activation stages or on certain leukocyte populations (monocytes, granulocytes, NK cells, lymphocytes) (Murphy 2012, Biosciences 2010). For different mammals (man, mouse, rat, but also swine, cattle, dog), a system of characterized leukocyte surface molecules primarily based on the recognition of these molecules by specific monoclonal antibodies (mabs) was summarized at international workshops as clusters of differentiation (CD) (Cobbold and Metcalfe 1994, Hopkins, Ross and Dutia 1993, Haverson et al. 2001, Mason et al. 2001). Using these mabs, it is not only possible to characterize the developmental and functional stage of different leukocyte subpopulations but also to define the interactions between these populations. For bony fish, such a system does not exist. Only a limited number of mabs against leukocyte surface molecules is available and most of them are strongly specific for species (Köllner et al. 2004, Köllner et al. 2001, Zhang et al. 2010, Ramirez-Gomez et al. 2012, Wen et al. 2011, DeLuca, Wilson and Warr 1983, Toda et al. 2011, Toda et al. 2009, Takizawa et al. 2011a, Hetland et al. 2010, Araki et al. 2008). The goal of this PhD work, therefore, was to develop monoclonal antibodies against surface markers of rainbow trout (Oncorhynchus mykiss) T cell population (chapter 2). The lymphocytes are characterized by the expression of a T cell receptor complex composed of TCR chains (α and β) and CD3 chains (α, β, γ, δ, ε and ζ). Cytotoxic T lymphocytes (CTLs) binds to MHC class I bound peptide on the infected host cell using their T cell receptor (TCR) and its co-receptor CD8 resulting in specific killing. Th cells recognize peptides through their T cell receptor (TCR) and their co-receptor CD4 after extracellular antigens uptake, processing and presentation via MHC class II by professional antigen presenting cells (macrophages, dendritic cells and B cells). During recent years, genes encoding MHC class I and II, TCR and their co-receptors CD8 and CD4 have been cloned in several fish species and antibodies have been developed to study protein expression in morphological and functional contexts. However, mabs specific for TCR or CD3 have not been established yet. Therefore, using pan-T cell marker specific mabs, the activation and kinetics of T cell subpopulation should be investigated (chapter 2). Moreover, a flow cytometry method was established using different lineage marker specific mabs to measure different leukocyte populations and their involvement in immune mechanisms of trout using a single tube assay (chapter 3). The first line of defense against altered body cells or pathogens is provided by evolutionarily ancient macrophages and natural killer (NK) cells. These innate mechanisms are well developed in bony fish. Two types of NK cell homologues have been described in fish: non-specific cytotoxic cells and NK-like cells (Shen et al. 2002, Shen et al. 2003, Shen et al. 2004, Fischer et al. 2013). Functional assays for innate and adaptive lymphocyte responses have been developed in only a few fish species. However, there are no tools available until now in trout to follow these cells directly in the immune response. The molecular characteristics and the expression on leukocyte subpopulations of CD56 were therefore analyzed. Furthermore, a mab that is specific for a molecule expressed only in NK cells but with uncommon expression kinetics was established (chapter 4). Overall, the established tools and methods allow a more detailed characterization of cellular immune mechanisms against intracellular pathogens in rainbow trout.
With the growing importance of advanced lighting technologies, customers expect additional functionality and higher comfort from fluorescent lamps. However, the ability to regulate light intensity (dimmed operation), in particular, exerts enormous stress on fluorescent lamps’ electrodes, leading to increased electrode erosion and significantly reduced lifetimes. During the operation of a fluorescent lamp, free barium (the main compound of the electrode emitter) is produced at the electrode responsible for lowering the work function in order to enable energy-efficient and durable electrodes with lifetimes of up to 20,000 hours. Despite their relatively long lifetimes, electrodes remain the lifetime-limiting factor of a fluorescent lamp. Therefore, for practical applications (e.g., maintaining quality control, adjusting operational parameters, and evaluating new electrode designs), electrode erosion is of special interest. The actual erosion-measurement methods determine a time-averaged erosion level over several hundred operation hours. Thus, a quasi-instantaneous measuring method (short measurement) is still necessary to determine erosion during operation. Such a method would allow us to compare erosion under different discharge conditions (currents, frequencies, or heating currents) from the same electrode in the same lamp. This work focuses on the determination of absolute electrode erosion during the stationary operation of commonly used fluorescent lamps. Commercial T8 lamps (fluorescent lamps with a diameter of 8/8 inch) are investigated at the operating mode of commonly used electronic ballasts with frequencies of several kHz. Operations under standard and dimmed conditions with an additional heating current to reduce electrode erosion are investigated. Electrode erosion is characterized by the erosion of barium, the main compound of the electrode. Therefore, laser-induced fluorescence (LIF), which is the most sensitive method for this application, is applied to determine the absolute densities of the eroded barium in the electrode region. These densities are affected by the plasma in the electrode region and do not directly represent the absolute barium erosion. To overcome this limitation, a new method based on a special measurement technique in combination with a barium-diffusion-model is developed to determine the absolute barium erosion based on the measured densities. It has been found that the barium densities in the electrode region are lower than the equilibrium pressures produced by the reduction of the barium oxide. This could be caused either by a reduced reaction rate, the reduced diffusion of the reactant (primarily barium oxide) or by reduced barium transport through the porous emitter. However, these results suggest that barium erosion depends on temperature and emitter structure, which vary over an electrode’s lifetime. For currents significantly higher than the nominal lamp current, a drastic increase in emitter evaporation is found. Such, an increase in the lamp current from 300 mA to 500 mA leads to an increase in emitter evaporation by a factor of five. Using the lamp for a long period of time under these conditions therefore reduces the lifetime by a factor of five. Notably, at this dramatically increased erosion level, the hot spot temperature only increases from 1120 K to 1170 K. Investigation of various frequencies from 50 Hz to 5 kHz revealed no significant dependence of emitter evaporation on frequency.
Geopolymers (GPs) are inorganic binders created by adding alkaline solution (e.g. KOH) to silicates such as furnace slag, fly ash or clay to dissolve Si and Al that polymerises and precipitates to form an inorganic binder material while hardening. GP properties are similar to ordinary Portland cement regarding their high compressive strength or low shrinkage but they are particularly notable for a high resistance to acid and fire. However, the most significant advantage of GP cements is their low CO2 footprint. The most common clay used as GP raw material is kaolin. The aim of this study is to investigate the suitability of illitic clays as a cheaper alternative to kaolin and determine the necessary preparation steps required to produce effective GP binder materials. Three clays dominated by dioctahedral 2:1 layer silicates, in particular interstratifications of mica and smectite were investigated: (1) Illitic clay from Friedland, Northern Germany, containing an irregularly stacked illite-smectite interstratification (R0 I-S), (2) rectorite from Arkansas, USA, as a regular interstratification of mica and smectite, and (3) clay stated as “sárospatakite” from Füzérradvány clay deposit, Northern Hungary, containing a long range ordered I-S (R3). The three types of I-S interstratification-rich clays were extensively characterised and the Friedland clay, as the most probable raw material for GP production, was studied in more detail including several size fraction analyses. These results are used to investigate and determine the parameters necessary to produce suitable precursors for GP binders. Different approaches of clay activation to yield a highly reactive material by milling and heating were examined. Milling was found to be suitable as a preparation step after heating breaking up sintering aggregates to create pathways for the alkaline solution, but not as a substitute for heating. Important parameters for the precursor design such as temperature, time, and heating rate are determined and discussed. Geopolymerisation is considered to be a multi-parameter system and is influenced strongly by the degree of dehydroxylation, Si:Al ratio, or amount of 5-fold coordinated Al. However, in contrast to kaolin-based systems, none of these parameters explain why the illitic Friedland clay heated to 875 °C was found to be most suitable for GP binders. Based on leaching experiments and specific surface area (AS) measurements of the heated Friedland clay, a conceptual model is presented to explain the observed relationship between the heating temperature and the subsequent compressive strength of the GP cement. An optimum between the counteracting reactions of decreasing AS (fewer particles must be covered with GP phase) and decreasing Si+Al dissolved (less GP phase created) is necessary, which exists at 875 °C for the Friedland clay. In this state enough GP phase is created to bind all remaining sintering aggregates to form a cement with high compressive strength. This relationship can be expressed as (Si+Al) / AS (sum of dissolved Si and Al divided by the surface area of grains that must be covered with GP phase), and can be used as a predictive tool for determining the optimal heating temperature. The results presented in this thesis indicate that illitic clays are suitable raw materials as GP binders if the necessary preparation steps of dehydroxylation, sintering and grinding are made. Proxies used to evaluate the optimal conditions for making GP binders are determined including the (Si+Al) / AS ratio as a key relationship that controls the cementation process and determines its ultimate hardness.