@article{StrackDeutsch2004,
  author    = {Strack, Fritz and Deutsch, Roland},
  title     = {Reflective and Impulsive Determinants of Social Behavior},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40447},
  year      = {2004},
  abstract  = {This article describes a 2-systems model that explains social behavior as a joint function of reflective and impulsive processes. In particular, it is assumed that social behavior is controlled by 2 interacting systems that follow different operating principles. The reflective system generates behavioral decisions that are based on knowledge about facts and values, whereas the impulsive system elicits behavior through associative links and motivational orientations. The proposed model describes how the 2 systems interact at various stages of processing, and how their outputs may determine behavior in a synergistic or antagonistic fashion. It extends previous models by integrating motivational components that allow more precise predictions of behavior. The implications of this reflective-impulsive model are applied to various phenomena from social psychology and beyond. Extending previous dual-process accounts, this model is not limited to specific domains of mental functioning and attempts to integrate cognitive, motivational, and behavioral mechanisms.},
  subject      = {Psychologie},
  language  = {en}
}
@phdthesis{Schmidt2004,
  author    = {Schmidt, Robert},
  title     = {The behavioral economics of foreign exchange markets - a psychological view on human expectation formation in foreign exchange markets},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14921},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The development of free floating exchange rates can hardly be explained by macroeconomic fundamentals as supposed by traditional economic theories. Therefore, prominent economists yet conclude that there exists an 'exchange rate disconnect puzzle' (see Obstfeld and Rogoff [2000]). The observable exchange rate trends are often attributed to an excessive speculative trading behavior of foreign exchange market participants. In this study we deal with psychological factors, which may be important for understanding the observable exchange rate movements. Thus, our study belongs to the new research field of behavioral economics, which considers the relevance of psychological factors in economic contexts. The main objective of behavioral economists is to develop a more realistic view of the actual human behavior in the context of economics. Therefore, behavioral economists often refer to the work of behavioral decision theorists, who introduced new concepts under the general heading of bounded rationality. Central to the concept of bounded rationality is the assumption that humans' actual behavior deviates from the ideal of economic rationality due to at least two reasons: first, decisions are usually based on an incomplete information basis (limited information) and, second, the information processing of human beings is limited by their computational capacities (limited cognitive resources). Due to these limitations people are forced to apply simplification mechanisms in information processing. Important simplification mechanisms, which play a decisive role in the process judgment and decision making, are simple heuristics. Simple heuristics can principally be characterized as simple rules of thumb, which allow quick and efficient decisions even under a high degree of uncertainty. In this study, our aim is to analyze the relevance of simple heuristics in the context of foreign exchange markets. In our view, the decision situation in foreign exchange markets can serve as a prime example for decision situations in which simple heuristics are especially relevant as the complexity of the decision situation is very high. The study is organized as follows. In Chapter II, we deal with the exchange rate disconnect puzzle. In particular, we discuss and check the main implications of the traditional economic approach for explaining exchange rate movements. The asset market theory of exchange rate determination implies that exchange rates are mainly driven by the development of macroeconomic fundamentals. Furthermore the asset market theory assumes that foreign exchange market participants form rational expectations concerning future exchange rate developments and that exchange rates are determined in efficient markets. Overall the empirical evidence suggests that the traditional approach for explaining exchange rate changes is at odds with the data. Chapter III addresses the existence of long and persistent trends in exchange rate time series. Overall, our empirical analysis reveals that exchange rates show a clear tendency to move in long and persistent trends. Furthermore, we discuss the relevance of speculation in foreign exchange markets. With regard to the impact of speculation, economic theory states that speculation can have either a stabilizing effect or a destabilizing effect on exchange rates. At the end of Chapter III, we examine the Keynesian view on the functioning of asset markets. In Chapter IV we explore the main insights from the new research field of behavioral economics. A main building block of behavioral economics is the concept of bounded rationality first introduced by Herbert Simon [1955]. In the centre of the concept of bounded rationality is a psychological analysis of the actual human judgment and decision behavior. In Chapter IV, we discuss the concept of bounded rationality in detail and illustrate important insights of behavioral decision theories. In particular, we deal with the relevance of simple heuristics in the context of foreign exchange markets. Chapter V provides experimental and empirical evidence for the suggested relevance of simple heuristics in foreign exchange markets. In the first experiment, we deal with the human expectation formation. We compare point forecasts of the EUR/USD exchange rate surveyed from professional analysts and experimentally generated point forecasts of students for a simulated exchange rate time series. The results show that the forecasting performance of both groups differs substantially. Afterwards we analyze the nature of expectation formation of both groups in detail to reveal similarities and differences, which allow us to draw reasonable explanations for the differences in the forecasting performances. In the second experiment, we analyze the expectation formation in an experimental foreign exchange market. This approach allows us to consider the relevance of expectation feedback as individuals' expectations directly influence the actual realization of the time series. Thus, Keynes' predictions on the importance of conventions in asset markets can be analyzed. Overall, both experiments reveal that the human beings tend to apply simple trend heuristics, when forming their expectations about future exchange rates. In the empirical part of Chapter V we deal with the usefulness of such simple trend heuristics in real world. Only if simple trend heuristics lead to profits in the specific environment of foreign exchange markets, their application can be recommended. Thus, we analyze the profitability of simple technical analysis tools in foreign exchange markets. Finally, Chapter VI provides concluding remarks.},
  subject      = {Devisenmarkt},
  language  = {en}
}
@phdthesis{Proels2004,
  author    = {Pr{\"o}ls, Reinhard},
  title     = {Regulation and function of extracellular invertases of tomato},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10260},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Wachstum und Entwicklung pflanzlicher Gewebe bedingen eine fortw{\"a}hrende Ver{\"a}nderung von Source-Sink Beziehungen. Gewebe mit einem Nettoexport (Source) oder - import (Sink) von Kohlenhydraten m{\"u}ssen ihren aktuellen Bedarf an Assimilaten entsprechend dem Entwicklungsstadium anpassen. Dar{\"u}ber hinaus haben Pflanzen als ortsgebundene Lebewesen Regulationsmechanismen entwickelt, die eine flexible Antwort der Assimilatverteilung auf spezielle Anforderungen des Habitats, wie biotische oder abiotische Stressfaktoren und wechselnde Lichtbedingungen, erm{\"o}glichen. Die Assimilatverteilung ist vielf{\"a}ltig reguliert und erfordert spezifische Enzymfunktionen, wie Zuckertransporter und saccharosespaltende Enzyme. Extrazellul{\"a}re Invertasen nehmen eine essentielle Funktion in der apoplastischen Phloementladung und in der Regulation von Source-Sink {\"U}berg{\"a}ngen ein. Dies spiegelt sich in dem Auftreten verschiedener Invertase- Isoenzyme mit speziellen Expressions- und Regulationsmustern wider, welche eine Koordination des Kohlenhydratmetabolismus in unterschiedlichen Geweben, zu unterschiedlichen Entwicklungsstufen und unter sich {\"a}ndernden Umweltbedingungen erm{\"o}glichen. Ein detailliertes Wissen {\"u}ber die Funktion extrazellul{\"a}rer Invertasen k{\"o}nnte eingesetzt werden, um Wachstum, Entwicklung oder Pathogenresisitenz von Nutzpflanzen gezielt zu ver{\"a}ndern. In der vorliegenden Studie wurden die Regulationsmuster und die Funktion dreier extrazellul{\"a}rer Invertasen aus Tomate, Lin5, Lin6 und Lin7 untersucht. Durch umfangreiche Promotorstudien konnte eine gewebe- und entwicklungsspezifische Expression dieser Isoenzyme und entsprechende Regulationsmuster offengelegt werden. Lin5 zeigt eine entwicklungsabh{\"a}ngige Expression in Fr{\"u}chten. Lin6 wird in fr{\"u}hen Entwicklungsstadien, beginnend mit der Samenkeimung, exprimiert; in ausgewachsenen Pflanzen ist eine Lin6 Expression nur in Pollen oder nach Verwundungsinduktion nachweisbar. Lin7 wird ausschließlich in Tapetum-Gewebe und Pollen exprimiert. Die hormonelle Regulation der Isogene wurde im Detail untersucht, hierbei konnten bekannte Ph{\"a}notypen, welche durch Gibberellins{\"a}ure und Jasmonate bedingt werden, mit Invertasefunktionen in Korrelation gebracht werden. Dar{\"u}ber hinaus konnte in einem funktionalen Ansatz gezeigt werden, dass Lin7 eine wichtige Rolle in der Pollenkeimung zukommt. Die vorliegende Arbeit stellt die umfassendste Untersuchung extrazellul{\"a}rer Invertasen w{\"a}hrend der Bl{\"u}tenentwicklung dar, an der drei Isoenzyme aus Tomate beteiligt sind. Dadurch, dass den einzelnen Invertasen Lin5, Lin6 und Lin7 individuelle Funktionen zugewiesen werden konnten, er{\"o}ffnen sich neue Erkenntnisse {\"u}ber die Kohlenhydratversorgung w{\"a}hrend der Bl{\"u}ten- und Fruchtentwicklung. F{\"u}r die untersuchten gewebespezifischen Promotoren er{\"o}ffnen sich zudem Anwendungsm{\"o}glichkeiten in der Biotechnologie, was insbesondere f{\"u}r den pollenspezifischen Lin7 Promotor zutrifft. Es konnte gezeigt werden, dass der Lin6 Promotor das Ziel von hormon-, zucker- und verwundungsvermittelten Signalwegen ist. Dar{\"u}ber hinaus konnte nachgewiesen werden, dass Elemente des circadianen Oszillators von A. thaliana mit dem Lin6 Promotor funktionell interagieren und die Lin6 Expression einem diurnalen Rhythmus unterliegt. Dieses komplexe Regulationsmuster spiegelt sich in vielen cis-aktiven Elementen wider, die im Lin6 Promotor vorgefunden wurden. Durch dieses Merkmal wird die These gest{\"u}tzt, dass verschiedene Stimuli {\"u}ber die extrazellul{\"a}re Invertase integriert werden und so eine koordinierte Zellantwort auf sich {\"a}ndernde interne und externe Bedingungen erm{\"o}glicht wird. Nachdem Zuckermolek{\"u}le ihrerseits die Expression von Lin6 induzieren, wird dadurch eine Amplifikation von Signalen {\"u}ber eine positive R{\"u}ckkopplungsschleife erm{\"o}glicht. Die Vielzahl an cis-aktiven Elementen und deren Anordnung im Lin6 Promotor stellen ein ideales Modellsystem dar, um Fragen in Bezug auf Signalinteraktion und -integration zu untersuchen. In einer umfangreichen Studie wurde der Lin6 Promotor erfolgreich als induzierbares Expressionssystem eingesetzt. Hierbei wurde ein Invertaseinhibitor unter der Kontrolle des cytokinininduzierbaren Lin6 Promotors in transgenen Tabakpflanzen exprimiert. Mit diesem Ansatz ist es gelungen einen kausalen Zusammenhang zwischen dem Hormon Cytokinin und extrazellul{\"a}ren Invertasen in der Seneszenzverz{\"o}gerung herzustellen. Diese Studie zeigt, dass induzierbare Expressionssysteme essentiell sind, um spezifische Fragestellungen auf molekularer Ebene kl{\"a}ren zu k{\"o}nnen. Bei der Klonierung obig genannter Promotorsequenzen haben sich zudem zwei interessante strukturelle Besonderheiten ergeben. Zum einen sind die Gene von Lin5 und Lin7 in einem Tandem auf dem Genom angeordnet, zum anderen konnte eine Transposoninsertion im Intron I des Lin5 Gens gezeigt werden. Mit einem Primerpaar, das aus der Transposaseregion dieses Transposons abgeleitet wurde, konnten entsprechende Sequenzen von mehreren Solanaceae Spezies gewonnen werden.},
  subject      = {Tomate},
  language  = {en}
}
@misc{Walz2004,
  type      = {Master Thesis},
  author    = {Walz, Yvonne},
  title     = {Measuring burn severity in forests of South-West Western Australia using MODIS},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14745},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Burn severity was measured within the Mediterranean sclerophyll forests of south-west Western Australia (WA) using remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS). The region of south-west WA is considered as a high fire prone landscape and is managed by the state government's Department of Conservation and Land Management (CALM). Prescribed fuel reduction burning is used as a management tool in this region. The measurement of burn severity with remote sensing data focused on monitoring the success and impact of prescribed burning and wildfire in this environment. The high temporal resolution of MODIS with twice daily overpasses in this area was considered highly favourable, as opportunities for prescribed burning are temporally limited by climatic conditions. The Normalised Burn Ratio (NBR) was investigated to measure burn severity in the forested area of south-west WA. This index has its heritage based on data from the Landsat TM/ETM+ sensors (Key and Benson, 1999 [1],[2]) and was transferred from Landsat to MODIS data. The measurement principally addresses the biomass consumption due to fire, whereas the change detected between the pre-fire image and the post-fire image is quantified by the {\"A}NBR. The NBR and the Normalised Difference Vegetation Index (NDVI) have been applied to MODIS and Landsat TM/ETM+ data. The spectral properties and the index values of the remote sensing data have been analysed within different burnt areas. The influence of atmospheric and BRDF effects on MODIS data has been investigated by comparing uncorrected top of atmosphere reflectance and atmospheric and BRDF corrected reflectance. The definition of burn severity classes has been established in a field trip to the study area. However, heterogeneous fire behaviour and patchy distribution of different vegetation structure made field classification difficult. Ground truth data has been collected in two different types of vegetation structure present in the burnt area. The burn severity measurement of high resolution Landsat data was assessed based on ground truth data. However, field data was not sufficient for rigorous validation of remote sensing data. The NBR index images of both sensors have been calibrated based on training areas in the high resolution Landsat image. The burn severity classifications of both sensors are comparable, which demonstrates the feasibility of a burn severity measurement using moderate spatial resolution 250m MODIS data. The normalisation through index calculation reduced atmospheric and BRDF effects, and thus MODIS top of at-mosphere data has been considered suitable for the burn severity measurement. The NBR could not be uniformly applied, as different structures of vegetation influenced the range of index values. Furthermore, the index was sensitive to variability in moisture content. However, the study concluded that the NBR on MODIS data is a useful measure of burn severity in the forested area of south-west WA.},
  subject      = {Westaustralien},
  language  = {en}
}
@phdthesis{Allgaier2004,
  author    = {Allgaier, Axel},
  title     = {Aeolian sand movement in an arid linear dune ecosystem, Nizzana, Western Negev, Israel},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14727},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In a three-year study the current aeolian transportation processes were examined in a linear dune area previously used for grazing near Nizzana at the Israeli-Egyptian border. The research area was subject to heavy grazing across the border, which led to the total destruction of the natural vegetation in the period of 1967 to 1982. As a consequence, intensified aeolian activity and significant changes of the morphology of the dunes were observed. After the end of the grazingg on the Israeli side, a rapid return of the vegetation in the interdune corridors and on the footslopes of the dunes took place. In addition also a reduction of obviously active areas on the dune crests was observed. The situation on Egyptian territory west the border remained unchanged until today. This study is aimed at understanding the changed aeolian morphodynamics east the border. The emphasis was placed on the investigation of the spatial and temporal distribution of aeolian sand transport as well as on the influencing factors morphology, surface condition and vegetation.},
  subject      = {Negev},
  language  = {en}
}
@phdthesis{Volkmann2004,
  author    = {Volkmann, Thorsten},
  title     = {Lattice gas models and simulations of epitaxial growth},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-13812},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In this PhD thesis, we develop models for the numerical simulation of epitaxial crystal growth, as realized, e.g., in molecular beam epitaxy (MBE). The basic idea is to use a discrete lattice gas representation of the crystal structure, and to apply kinetic Monte Carlo (KMC) simulations for the description of the growth dynamics. The main advantage of the KMC approach is the possibility to account for atomistic details and at the same time cover MBE relevant time scales in the simulation. In chapter 1, we describe the principles of MBE, pointing out relevant physical processes and the influence of experimental control parameters. We discuss various methods used in the theoretical description of epitaxial growth. Subsequently, the underlying concepts of the KMC method and the lattice gas approach are presented. Important aspects concerning the design of a lattice gas model are considered, e.g. the solid-on-solid approximation or the choice of an appropriate lattice topology. A key element of any KMC simulation is the selection of allowed events and the evaluation of Arrhenius rates for thermally activated processes. We discuss simplifying schemes that are used to approximate the corresponding energy barriers if detailed knowledge about the barriers is not available. Finally, the efficient implementation of the MC kinetics using a rejection-free algorithm is described. In chapter 2, we present a solid-on-solid lattice gas model which aims at the description of II-VI(001) semiconductor surfaces like CdTe(001). The model accounts for the zincblende structure and the relevant surface reconstructions of Cd- and Te-terminated surfaces. Particles at the surface interact via anisotropic nearest and next nearest neighbor interactions, whereas interactions in the bulk are isotropic. The anisotropic surface interactions reflect known properties of CdTe(001) like the small energy difference between the c(2x2) and (2x1) vacancy structures of Cd-terminated surfaces. A key element of the model is the presence of additional Te atoms in a weakly bound Te* state, which is motivated by experimental observations of Te coverages exceeding one monolayer at low temperatures and high Te fluxes. The true mechanism of binding excess Te to the surface is still unclear. Here, we use a mean-field approach assuming a Te* reservoir with limited occupation. In chapter 3, we perform KMC simulations of atomic layer epitaxy (ALE) of CdTe(001). We study the self-regulation of the ALE growth rate and demonstrate how the interplay of the Te* reservoir occupation with the surface kinetics results in two different regimes: at high temperatures the growth rate is limited to one half layer of CdTe per ALE cycle, whereas at low enough temperatures each cycle adds a complete layer. The temperature where the transition between the two regimes occurs depends mainly on the particle fluxes. The temperature dependence of the growth rate and the flux dependence of the transition temperature are in good qualitative agreement with experimental results. Comparing the macroscopic activation energy for Te* desorption in our model with experimental values we find semiquantitative agreement. In chapter 4, we study the formation of nanostructures with alternating stripes during submonolayer heteroepitaxy of two different adsorbate species on a given substrate. We evaluate the influence of two mechanisms: kinetic segregation due to chemically induced diffusion barriers, and strain relaxation by alternating arrangement of the adsorbate species. KMC simulations of a simple cubic lattice gas with weak inter-species binding energy show that kinetic effects are sufficient to account for stripe formation during growth. The dependence of the stripe width on control parameters is investigated. We find an Arrhenius temperature dependence, in agreement with experimental investigations of phase separation in binary or ternary material systems. Canonical MC simulations show that the observed stripes are not stable under equilibrium conditions: the adsorbate species separate into very large domains. Off-lattice simulations which account for the lattice misfit of the involved particle species show that, under equilibrium conditions, the competition between binding and strain energy results in regular stripe patterns with a well-defined width depending on both misfit and binding energies. In KMC simulations, the stripe-formation and the experimentally reported ramification of adsorbate islands are reproduced. To clarify the origin of the island ramification, we investigate an enhanced lattice gas model whose parameters are fitted to match characteristic off-lattice diffusion barriers. The simulation results show that a satisfactory explanation of experimental observations within the lattice gas framework requires a detailed incorporation of long-range elastic interactions. In the appendix we discuss supplementary topics related to the lattice gas simulations in chapter 4.},
  subject      = {Kristallwachstum},
  language  = {en}
}
@phdthesis{Engelhardt2004,
  author    = {Engelhardt, Catherine Marie},
  title     = {Identification and characterisation of the Spred protein family},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11456},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The subject of this thesis was the cloning and the initial biochemical and functional characterisation of novel human proteins with an N-terminal Ena-VASP homology (EVH)-1 domain and a C-terminal Sprouty homologous region (SPR), which are related to the Drosophila AE33 protein. During the course of this work, three mouse homologues of the AE33 fly protein have been reported and termed Sprouty-related protein with an EVH-1 domain 1, 2 and 3 (Spred-1, -2, -3)(Wakioka et al, 2001; Kato et al, 2003). Spred-1, -2 and -3 are membrane associated substrates of receptor tyrosine kinases and they act as negative regulators of the Ras pathway during growth factor stimulation. As the Spred-family members seem to exert similar functions, the specific function of each member remains enigmatic. Therefore, we investigated the mRNA and protein expression patterns of the two murine protein family members Spred-1 and Spred-2 on the whole organ level. Furthermore, we focussed on the cellular localisation and the role of human and murine Spred-2 in the organism. The expression patterns of Spred-1 and Spred-2 differed markedly among various tissues and cell types. In mouse, Spred-1 is abundantly expressed in adult brain, cerebellum, and fetal tissues, whereas Spred-2 was ubiquitously expressed. In humans, Spred-2 was found to be strongly expressed in glandular epithelia and in invasive cytotrophoblasts, and at the subcellular level its immunoreactivity was associated with secretory vesicles and was found to colocalise with Rab11 GTPase. The new human Spred gene family was investigated in detail. Cloning of the fulllength form of human Spred-2 resulted in an 1254 bp coding sequence, corresponding to a 418 amino-acids protein. Immunoblotting with a set of affinitypurified antibodies confirmed the expression of a 47 kDa protein and suggested the presence of additional differently sized variants. Cloning of various shortened Spred- 2 mRNAs and identification of 2 additional human Spred genes (localised on different chromosomes) with their respective EST (expressed sequence tag) revealed that the new human Spred gene family displays extensive splicing, leading to the generation of short and long Spred proteins. All protein isoforms and splicing variants contain an EVH1-domain located at the N-terminus of the protein. The full-length forms ("a" forms) comprised the SPR, another functional domain localised at the C-terminus whereas the short variants (Spred-1b, 2 c-e, 3 c) lack the entire C-terminal SPR domain or part of it. The existence of short and long splicing variants of Spred-1, -2 and -3 revealed a common principle of organisation and splicing pattern in the Spred family. Functional analyses of the 5 cloned Spred-2 splicing variants revealed differential subcellular localisation and differential regulation of serum- and EGF- mediated ERK activation in HEK-293 cells. Taken together, these results indicate a highly specific expression pattern of Spred-1 and Spred-2 in various tissues suggesting a specific physiological role for the individual Spred isoform in these tissues. For example, Spred-2 appears to be involved in regulating secretory pathways. Furthermore, the human Spred family contains three genes, which are subject to extensive alternative splicing resulting in at least 8 different proteins with differential subcellular localisation and differential regulatory potential of the MAPK pathways during growth factor stimulation.},
  subject      = {Spred Protein},
  language  = {en}
}
@phdthesis{Li2004,
  author    = {Li, Jie},
  title     = {Differential effects of neuromelanin and synthetic dopamine melanin on cell lines},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-13588},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {xxx},
  language  = {en}
}
@phdthesis{Muellner2004,
  author    = {M{\"u}llner, Antje},
  title     = {Breeding ecology and related life-history traits of the hoatzin, Opisthocomus hoazin, in a primary rainforest habitat},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-13239},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The hoatzin (Opisthocomus hoazin) is an enigmatic bird that lives in the riparian lowlands of northern South America. Among its peculiar attributes are 1) microbial foregut fermentation, unique in birds, to convert plant cellulose in the foliage which it consumes into simple sugars, 2) an ongoing debate about the puzzling taxonomic position, although a relationship to the Cuculiformes appears likely, 3) adaptive wing claws in the young which are used for climbing, and 4) co-operative breeding behaviour. Despite the information available on digestive mode and taxonomy little has been published on its breeding biology and behaviour and until now almost all knowledge was based on a study in the savannah of Venezuela. This is the first detailed study of the hoatzin's nesting ecology in a rainforest habitat. From 1995-1998 and in 2000 I monitored a hoatzin population which consisted of approximately 700 individuals in an Amazonian rainforest in Ecuador situated in the Cuyabeno Wildlife Reserve (between 0°02' N, 76°0' W, 0°03' S, and 76°14' W). The area is composed of various black water lagoons and small rivers, flooded forests and terra firme forest. Primarily, I examined group composition and breeding pattern and success related to traits such as clutch and egg size, offspring sex ratio and the number of parents involved in a common breeding attempt. Apart from standardised observations and monitoring I took blood samples from chicks, which were later used for molecular sexing and for DNA fingerprints. Food plants were collected and determined and a rough habitat mapping was conducted. Since the impacts of boat tourism in the area became apparent I investigated the interactions of adult and young hoatzins with tourists and measured the plasma concentration of the hormone corticosterone in chicks as an indicator of stress. Each chapter has its own introduction to the specific topic and can be read independently. The main findings of this study are: The reproduction of the hoatzin was timed strictly following the bimodal rainy pattern in the area. There was only one breeding attempt per year. Only 18\% of breeding attempts ended successfully with at least one fledgling. Incubation started with the first egg laid and led to hatching asynchrony. In most cases only the A-chick survived and there is evidence for a brood reduction strategy. I observed egg size variation patterns both within the clutches and between the clutches. Approximately 80\% of breeding attempts were carried out with auxiliaries. Units with alloparentals had a higher breeding success than single pairs. The results indicate a trade-off between helping and group size. DNA band-sharing comparisons revealed the existence of joint-nests, where several females laid their eggs in one single nest. The clutches of these joint-nests suffered severe egg loss during all stages of incubation. Breeding success did not differ between single- and joint-nests. The primary offspring sex ratio was biased towards daughters. There was no differential mortality between the sexes until fledging. Individual breeding units employed an adaptive production of offspring of each sex according to their current group size. Rainforest tourism negatively influenced the survival and growth of young, not yet fledged hoatzins. In addition tourist-exposed young showed a stronger hormonal stress response than their conspecifics from undisturbed sites. In contrast, breeding adults appear to have habituated to tourist boats and exposure to observers.},
  subject      = {Hoatzins},
  language  = {en}
}
@phdthesis{Kittel2004,
  author    = {Kittel, Olaf},
  title     = {CP violation in production and decay of supersymmetric particles},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12767},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In dieser Dissertation untersuchen wir CP verletzende Effekte von MSSM-Phasen in Produktion und Zwei-Teilchen-Zerfaellen von Neutralinos, Charginos und Sfermionen. Fuer verschiedene supersymmetrische Prozesse definieren und berechnen wir CP-ungerade Asymmetrien, welche auf Spatprodukten basieren. Wir zeigen numerische Ergebnisse fuer Elektron-Positron-Kollisionen an einem zukuenftigen Linearbeschleuniger mit einer Energie von 500 - 800 GeV, hoher Luminositaet und longitudinal polarisierten Strahlen.},
  subject      = {Supersymmetrisches Teilchen},
  language  = {en}
}
@phdthesis{Deppisch2004,
  author    = {Deppisch, Frank},
  title     = {Towards a reconstruction of the SUSY seesaw model},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12757},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In this work, we studied in great detail how the unknown parameters of the SUSY seesaw model can be determined from measurements of observables at or below collider energies, namely rare flavor violating decays of leptons, slepton pair production processes at linear colliders and slepton mass differences. This is a challenging task as there is an intricate dependence of the observables on the unknown seesaw, light neutrino and mSUGRA parameters. In order to separate these different influences, we first considered two classes of seesaw models, namely quasi-degenerate and strongly hierarchical right-handed neutrinos. As a generalisation, we presented a method that can be used to reconstruct the high energy seesaw parameters, among them the heavy right-handed neutrino masses, from low energy observables alone.},
  subject      = {Supersymmetrie},
  language  = {en}
}
@phdthesis{Bechmann2004,
  author    = {Bechmann, Michael},
  title     = {Dynamics in quantum spin glass systems},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12519},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {This thesis aims at a description of the equilibrium dynamics of quantum spin glass systems. To this end a generic fermionic SU(2), spin 1/2 spin glass model with infinite-range interactions is defined in the first part. The model is treated in the framework of imaginary-time Grassmann field theory along with the replica formalism. A dynamical two-step decoupling procedure, which retains the full time dependence of the (replica-symmetric) saddle point, is presented. As a main result, a set of highly coupled self-consistency equations for the spin-spin correlations can be formulated. Beyond the so-called spin-static approximation two complementary systematic approximation schemes are developed in order to render the occurring integration problem feasible. One of these methods restricts the quantum-spin dynamics to a manageable number of bosonic Matsubara frequencies. A sequence of improved approximants to some quantity can be obtained by gradually extending the set of employed discrete frequencies. Extrapolation of such a sequence yields an estimate of the full dynamical solution. The other method is based on a perturbative expansion of the self-consistency equations in terms of the dynamical correlations. In the second part these techniques are applied to the isotropic Heisenberg spin glass both on the Fock space (HSGF) and, exploiting the Popov-Fedotov trick, on the spin space (HSGS). The critical temperatures of the paramagnet to spin glass phase transitions are determined accurately. Compared to the spin-static results, the dynamics causes slight increases of T_c by about 3\% and 2\%, respectively. For the HSGS the specific heat C(T) is investigated in the paramagnetic phase and, by way of a perturbative method, below but close to T_c. The exact C(T)-curve is shown to exhibit a pronounced non-analyticity at T_c and, contradictory to recent reports by other authors, there is no indication of maximum above T_c. In the last part of this thesis the spin glass model is augmented with a nearest-neighbor hopping term on an infinite-dimensional cubic lattice. An extended self-consistency structure can be derived by combining the decoupling procedure with the dynamical CPA method. For the itinerant Ising spin glass numerous solutions within the spin-static approximation are presented both at finite and zero temperature. Systematic dynamical corrections to the spin-static phase diagram in the plane of temperature and hopping strength are calculated, and the location of the quantum critical point is determined.},
  subject      = {Spinglas},
  language  = {en}
}
@phdthesis{Stey2004,
  author    = {Stey, Thomas Josef},
  title     = {Di(benzothiazol-2-yl)phosphane - Studies on a Janus Head Ligand -},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12330},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The design of ligands is one of the most important and simultaneously challenging fields of research in modern inorganic chemistry. The aim is to synthesise ligands that can serve as coordination units for a broad variety of metal fragments and different purposes. The ligands have to be very flexible concerning their donating behaviour and geometrical prerequisites in order to correspond to the required metal fragments.},
  subject      = {Phosphine},
  language  = {en}
}
@phdthesis{Dahnken2004,
  author    = {Dahnken, Christopher},
  title     = {Spectral properties of strongly correlated electron systems},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12238},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {We investigate the single particle static and dynamic properties at zero temperature within the Hubbard an three-band-Hubbard model for the superconducting copper oxides. Based on the recently proposed self-energy functional approach (SFA) [M.Potthoff, Eur. Phys. J. B 32 429 (2003)], we present an extension of the cluster-perturbation theory (CPT) to systems with spontaneous broken symmetry. Our method accounts for both short-range correlations and long-range order. Short-range correlations are accurately taken into account via the exact diagonalization of finite clusters. Long-range order is described by variational optimization of a ficticious symmetry-breaking field. In comparison with related cluster methods, our approach is more flexible and, for a given cluster size, less demanding numerically, especially at zero temperature. An application of the method to the antiferromagnetic phase of the Hubbard model at half-filling shows good agreement with results from quantum Monte-Carlo calculations. We demonstrate that the variational extension of the cluster-perturbation theory is crucial to reproduce salient features of the single-particle spectrum of the insulating cuprates. Comparison of the dispersion of the low-energy excitations with recent experimental results of angular resolved photoemission spectroscopy (ARPES) allows us to fix a consistent parameter set for the one-band Hubbard model with an additional hopping parameter t' along the lattice diagonal. The doping dependence of the single-particle excitations is studied within the t-t-U Hubbard model with special emphasis on the electron doped compounds. We show, that the ARPES results on the band structure and the Fermi surface of Nd{2-x}Ce_xCuOCl_{4-\delta} are naturally obtained within the t-t-U Hubbard model without further need for readjustment or fitting of parameters, as proposed in recent theoretical considerations. We present a theory for the photon energy and polarization dependence of ARPES intensities from the CuO2 plane in the framework of strong correlation models. The importance of surface states for the observed experimental facts is considered. We show that for electric field vector in the CuO_2 plane the 'radiation characteristics' of the O 2p_{\sigma} and Cu 3d_{x^2-y^2} orbitals are strongly peaked along the CuO_2 plane, i.e. most photoelectrons are emitted at grazing angles. This suggests that surface states play an important role in the observed ARPES spectra, consistent with recent data from Sr_2CuCl_2O_2. We show that a combination of surface state dispersion and Fano resonance between surface state and the continuum of LEED-states may produce a precipitous drop in the observed photoelectron current as a function of in-plane momentum, which may well mimic a Fermi-surface crossing. This effect may explain the simultaneous 'observation' of a hole-like and an electron-like Fermi surfaces in Bi_2Sr_2CaCu_2O_{8+\delta} at different photon energies.},
  subject      = {Hochtemperatursupraleiter},
  language  = {en}
}
@phdthesis{Eckl2004,
  author    = {Eckl, Thomas},
  title     = {Phenomenological phase-fluctuation model for the underdoped cuprates},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-12115},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In this thesis, a phenomenological phase-fluctuation model for the pseudogap regime of the underdoped cuprates was discussed. The key idea of the phase-fluctuation scenario in the high-T_c superconductors is the notion that the pseudogap observed in a wide variety of experiments arises from phase fluctuations of the superconducting gap. In this scenario, below a mean-field temperature scale T_c^{MF}, a d_{x^2-y^2}-wave gap amplitude is assumed to develop. However, the superconducting transition is suppressed to a considerably lower transition temperature T_c by phase fluctuations. In the intermediate temperature regime between T_c^{MF} and T_c, phase fluctuations of the superconducting order parameter give rise to the pseudogap phenomena. The phenomenological phase-fluctuation model discussed in this thesis consists of a two-dimensional BCS-like Hamiltonian where the phase of the pairing-amplitude is free to fluctuate. The fluctuations of the phase were treated by a Monte Carlo simulation of a classical XY model. First, the density of states was calculated. The quasiparticle tunneling conductance (dI/dV) obtained from our phenomenological phase fluctuation model was able to reproduce characteristic and salient features of recent scanning-tunneling studies of Bi2212 and Bi2201 suggesting that the pseudogap behavior observed in these experiments arises from phase fluctuations of the d_{x^2-y^2}-wave pairing gap. In calculating the single-particle spectral weight, we were further able to show how phase fluctuations influence the experimentally observed quasiparticle spectra in detail. In particular the disappearance of the BCS-Bogoliubov quasiparticle band at T_c and the change from a more V-like superconducting gap to a rather U-like pseudogap above T_c can be explained in a consistent way by assuming that the low-energy pseudogap in the underdoped cuprates is due to phase fluctuations of a local d_{x^2-y^2}-wave pairing gap with fixed magnitude. Furthermore, phase fluctuations can explain why the pseudogap starts closing from the nodal points, whereas it rather fills in along the anti-nodal directions and they can also account for the characteristic temperature dependence of the superconducting (pi,0)-photoemission-peak. Next, we have shown that the "violation" of the low-frequency optical sum rule recently observed in the SC state of underdoped Bi2212, which is associated with a reduction of kinetic energy, can be related to the role of phase fluctuations. The decrease in kinetic energy is due to the sharpening of the quasiparticle peaks close to the superconducting transition at T_c == T_{KT}, where the phase correlation length xi diverges. A detailed analysis of the temperature and frequency dependence of the optical conductivity sigma(omega)=sigma_1(omega)+i sigma_2(omega) revealed a superconducting scaling of sigma_2(omega), which starts already above T_c, exactly as observed in high-frequency microwave conductivity experiments on Bi2212. On the other hand, our model was only able to account for the characteristic peak, which is observed in sigma_1(omega) close to the superconducting transition, after the inclusion of an additional marginal-Fermi-liquid scattering-rate in the optical conductivity formula. Finally, we calculated the static uniform diamagnetic susceptibility. It turned out that the precursor effects of the fluctuating diamagnetism above T_c are very small and limited to temperatures close to T_c in a phase-fluctuation scenario of the pseudogap. Instead, the temperature dependence of the uniform static magnetic susceptibility is dominated by the Pauli spin susceptibility, which displayed a very characteristic temperature dependence, independent of the details of the gap function used in our model. This temperature dependence is qualitatively very similar to the experimentally observed change of the Knight-shift as a function of temperature in underdoped Bi2212.},
  subject      = {Hochtemperatursupraleiter},
  language  = {en}
}
@phdthesis{Klukowska2004,
  author    = {Klukowska, Anna},
  title     = {Switching hybrid polymers with physically and covalently entrapped organic photochromes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11721},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The aim of this work was to test and tailor new sol gel derived hybrid polymer coatings for the incorporation of photochromic spirooxazines and chromenes. The development and optimisation of work was performed via two different routes (dye and matrix ones), that led to photochromic multi-layer coating systems with coloration depth and photostabilities comparable to commercially available products. Hybrid sol-gel derived polymers were found to be suitable host materials for photochromic dyes. Matrix properties and the type of entrapment heavily influence the photochromic activity, as well as the degradation rate and the kinetics of incorporated dyes. Dyes incorporated within more polar and rigid matrices were found to show slower kinetics and higher coloration but associated with faster photodegradation. On the other hand, hosts with less polar sites, low residual water concentration and low rigidity are preferable in terms of photostability. Significant differences were found for physically incorporated and covalently grafted chromophores. Using silylated dyes that can participate in the sol-gel process, the photodegradation rate of the whole system can be decreased as compared to the physically entrapped systems. The higher photostability and slower kinetics for covalently bonded photochromes is probably due to sterical hindrance. Addition of proper stabilisers increases the photostability: The employment of UV light stabilisers, excited state quenchers and HALS was found to be beneficial but not sufficient. Besides the presence of stabilisers, also the reduction of oxygen migration into the coating (by a hard top coat and an inorganic anti reflective coating) strongly increases stability of photochromes. Finally, it was found that the separation of photochromes within two (or more) different layers leads to a further improvement of the coloration and fatigue behaviour of the whole coating stack, presumably by preventing the contact of dye molecules with excited states of other molecules or their degradation products. These latter findings are considered to pave the way for stable photochromic coatings based on hybrid polymers. Future development should be directed towards more photostable yellow and red switching dyes. The results of the present investigations should help to choose the most suitable molecular environments for the tested photochromes in terms of photostability, kinetics and activity, which is considered relevant with respect to potential applications, in particular in the ophthalmic sector. Furthermore, the interesting combination of properties of this type of materials offers a large potential with regard to many applications, such as coatings for sunglasses, radiation protectors, filters, sunroofs, reversible markings, printing applications and smart textiles.},
  subject      = {Metallorganische Polymere},
  language  = {en}
}
@phdthesis{Herzner2004,
  author    = {Herzner, Gudrun},
  title     = {Evolution of the pheromone communication system in the European Beewolf Philanthus triangulum F. (Hymenoptera: Crabronidae)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11651},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Darwin's theory of sexual selection explains the evolution of flamboyant male traits through female choice. It does not, however, address the question why males typically court and females choose. This asymmetry is now thought to be the result of the dichotomy in reproductive expenditures: Females invest primarily in parental care and males invest predominantly in mate attraction or competition. Based on this view, several hypotheses for the origin and maintenance of female preferences have been proposed. They include the classical sexual selection models, i.e. female choice for direct and indirect benefits as well as the more recent concepts of female choice for genetic compatibility and receiver bias models. The complementary choice scenario assumes that females choose mates with regard to genetic compatibility. The receiver bias concept views male traits and female preferences within the framework of communication theory and encompasses various more or less distinct models, two of which are sensory exploitation and sensory trap. Both models postulate that male signals evolved in response to pre-existing perceptual biases of females. The sensory trap hypothesis additionally emphasizes that pre-existing female preferences for certain cues evolved in non-sexual contexts, like e.g. foraging. Males that mimic these cues and elicit a favourable out-of-context response by females may increase their reproductive success. This thesis examines the evolution of the pheromone communication in the European Beewolf Philanthus triangulum. Beewolf females are specialized hunters of honeybees and provision their progeny with paralyzed prey. Male beewolves establish and scent mark territories with a pheromone from a head gland to court females. The concordant occurrence of the otherwise rare alcohol (Z)-11-eicosen-1-ol in the male pheromone and in the alarm pheromone of honeybees, the exclusive prey of the females, suggests a sensory trap process as an explanation for the evolution of the male pheromone in P. triangulum. According to this hypothesis, we tested three predictions: First, foraging honeybees should emit eicosenol. Via chemical analysis we could show that honeybee workers in fact smell of eicosenol during foraging. The occurrence of eicosenol on the cuticle and in the headspace of honeybees is a new finding. Second, beewolf females should use eicosenol as a cue for prey detection or identification. Using behavioural assays, we demonstrated that prey recognition in beewolf females is accomplished by olfactory cues and that eicosenol is an essential cue in this process. The sensory sensitivity of beewolf females to eicosenol must be extremely high, since they perceive the trace amounts present in the head space of honeybees. This sensitivity may be due to specialized olfactory receptors on the antennae of beewolf females. An inventory of the flagellar sensilla of both sexes showed that females carry one type of sensillum that is missing in males, the large sensillum basiconicum. This chemo-sensitive sensillum most likely plays a role in prey recognition. The third prediction is that beewolf males incorporate bee-like substances, including eicosenol, into their pheromone, and possibly catch females in a sensory trap. A reanalysis of the male pheromone revealed, among others, eicosenol and several alkanes and alkenes as pheromonal compounds. Our own analyses of the chemical profiles of honeybee workers and beewolf pheromone disclosed a surprisingly strong resemblance between the two. Eight of the eleven substances of the male pheromone are also present on the cuticle and in the headspace of honeybees. Notwithstanding this similarity, the male pheromone does not function as a sensory trap for females. Nevertheless, the extensive congruence between the odour bouquets of the females' prey and the male pheromone strongly suggests that the male signal evolved to exploit a pre-existing female sensory bias towards bee odour, and, thus represents a case of sensory exploitation. In addition to the above described scenario concerning mostly the 'design' of the male pheromone, we addressed possible indirect benefits female beewolves may gain by basing their mating decisions on signal 'content'. We show that the pheromone of male beewolves varies between families and may, thus, contain information about the degree of relatedness between the female and a potential mate. Females could use this information to choose genetically complementary males to avoid inbreeding and the production of infertile diploid sons. Collectively, our results provide strong evidence for a receiver bias process in the evolution of the male pheromone of P. triangulum. They further indicate that the pheromone composition may subsequently have been influenced by other natural or sexual selection pressures, like e.g. complementary female choice.},
  subject      = {Philantus},
  language  = {en}
}
@phdthesis{Schmitt2004,
  author    = {Schmitt, Thomas},
  title     = {Communication in the hymenoptera : chemistry, ecology and evolution},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11267},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Insects exhibit complex systems of communication with chemical signalling being the most important mode. Although there are many studies on chemical communication in insects, the evolution of chemical signals is not well understood. Due to the conflict of interests between individuals, different selective pressures might act on sender and receiver. In this thesis I investigate different types of communication where either the sender, the receiver or both parties yield benefits. These studies were conducted with one digger wasp species, honeybees, one chrysidid wasp, and three ant species. Senders might benefit by exploiting existing preferences of receivers. Such sensory exploitation might influence the evolution of male signals that are designed to attract females. The sex pheromone of male European beewolves Philanthus triangulum (Hymenoptera, Crabronidae) might have evolved according to the sensory exploitation hypothesis. A three-step scenario is supported by our studies. First, a major component of the honeybee alarm pheromone, (Z)-11-eicosen-1-ol, is also found on the cuticles and in the air surrounding foraging honeybees. Second, it could be shown, that (Z)-11- eicosen-1-ol plays a crucial role as kairomone for prey identification of honeybees by beewolf females. Third, a reanalysis of the beewolf male sex pheromone shows a remarkable similarity of compounds between the pheromone and the honeybee cuticle, besides the co-occurrence of (Z)-11-eisosen-ol. The majority of the cuticular hydrocarbons of honeybees occur also in the headspace of foraging workers. These results strongly support the hypothesis that beewolf males evolved a pheromone that exploits the females' pre-existing sensory sensitivity. In addition, the male sex pheromone shows a significantly higher similarity among brothers than among non-related individuals, which might enable beewolf females to discriminate against brothers and avoid detrimental effects of breeding. Together with the studies on the possible sensory exploitation this result shows that both, male and female beewolves probably gain more benefits than costs from the pheromone communication and, thus, the communication system as a whole can be regarded as cooperative. To maintain the reproductive division of labour in eusocial colonies, queens have to signal their presence and fecundity. In the ant Camponotus floridanus (Hymenoptera, Formicidae) queens mark their own eggs with a distinctive pattern of cuticular hydrocarbons. Two different hypotheses have been developed. One suggests a form of worker manipulation by the queen. The alternative hypothesis assumes a cooperative signal that provides information on the condition of the queen. The results of our investigation clearly favour the latter hypothesis. Chemical mimicry is a form of non-cooperative communication that benefits predominantly the sender. We provided conclusive evidence that the cockoo wasp, Hedychrum rutilans (Hymenoptera, Chrysididae), the primary brood parasitoid of Philanthus triangulum, evades recognition by beewolf females most probably by chemical mimicry of the odour of its host. Furthermore, the adaptation of the chemical signature in the social ant parasite Protomognathus americanus (Hymenoptera, Formicidae) to its Leptothorax (Hymenoptera, Formicidae) hosts was investigated. Although this parasite is principally adapted to its hosts' cuticular hydrocarbon profile, there are still pronounced differences between the profiles of parasites and hosts. This might be explained by the trade-off, which the parasites faces when confronted locally with two host species with different cuticular hydrocarbon profiles. Non-cooperative communication in the sense that only receivers benefit was discovered in the exploitation of honeybees volatile cuticular hydrocarbons by beewolf females. By using emitted (Z)-11-eicosen-1-ol as a kairomone, the receiver, the beewolf female, yields the benefits and the sender, the honeybee prey, bears all the costs. The results of these studies contribute to the understanding of the evolution of cooperative and non-cooperative communication with chemical signals taking into account differential benefits for sender and/or receiver.},
  subject      = {Hautfl{\"u}gler},
  language  = {en}
}
@phdthesis{Daiss2004,
  author    = {Daiß, J{\"u}rgen Oliver},
  title     = {Synthesis of sila-analogs and silicon-containing derivatives of drugs and development and application of the Si-2,4,6-trimethoxyphenyl moiety as a novel protecting group in organosilicon chemistry},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11187},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The present work describes the synthesis of sila-venlafaxine, disila-bexarotene, disila-AG-045572 (disila-CMPD1), a series of silicon-based allosteric modulators of muscarinic receptors, and a partial synthesis of sila-gabapentin. Crystal structure data of rac-sila-venlafaxine hydrochloride, (R)-sila-venlafaxine hydrobromide, bexarotene, disila-bexarotene, and disila-AG-045572 (disila-CMPD1) are included. Studies on the biological activities of sila-venlafaxine and of silicon-based allosteric modulators of muscarinic receptors are discussed. The Si-2,4,6-trimethoxyphenyl (Si-2,4,6-TMOP) moiety is described as a novel, acid-labile protecting group in organosilicon chemistry. The synthesis of chlorotris(chloromethyl)silane and tris(chloromethyl)methoxysilane is described.},
  subject      = {Wirkstoff},
  language  = {en}
}
@phdthesis{Kukulus2004,
  author    = {Kukulus, Matthias},
  title     = {A quantitative approach to the evolution of the central Walvis Basin offshore NW-Namibia : structure, mass balancing, and hydrocarbon potential},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-11075},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Rifting and breakup of Westgondwana in the Late Jurassic/ Early Cretaceous initiated the formation of the South Atlantic and its conjugated pair of passive continental margins. The Walvis Basin offshore NW-Namibia is an Early Cretaceous to recent depositional centre with a typically wedge-shaped postrift sedimentary succession covering an area of 105000km2. A 2D model transect across the central Walvis Basin and adjacent onshore areas is used as a case study to investigate quantitatively the denudational history of the evolving passive margin and the related contemporaneous depositional postrift evolution offshore. The database for both the onshore and offshore part of the model traverse is well constrained by own field work, published data as well as by seismic and well data supported by samples. The ultimate goal of this project is to present an integrated approach towards a quantitative link between surface processes and internal processes in terms of a mass and process balance.},
  subject      = {Namibia <Nordwest>},
  language  = {en}
}
@phdthesis{Xiao2004,
  author    = {Xiao, Zheng},
  title     = {Blimp-1 Regulates Terminal Differentiation of T Cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10530},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The transcriptional repressor-Blimp-1 terminates differentiation of B lymphocytes as well as myeloid cells. Our data show that Blimp-1 is highly expressed in freshly isolated murine primary T lymphocytes, particularly its minor splice variant. Ectopic expression of Blimp-1 by retroviral transduction neither dramatically altered secretion of IFN-{\~a} or IL-4 nor did it induce the ability to suppress as regulatory T cells. However, induction of Blimp-1 resulted in not only a significant reduction in the production of IL-2 but also an inability to proliferate as well as in the reduced viability. These results demonstrate that Blimp-1 might mark end stages of lineage differentiation in T cells.},
  language  = {en}
}
@phdthesis{Vukicevic2004,
  author    = {Vukicevic, Vladimir},
  title     = {Mechanisms of apoptosis modulation and their contribution to genomic instability in tumor cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10605},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The concept of programmed cell death has been increasingly considered from various aspects since early 1970's. Primarily, knowledge of apoptosis referred to morphological changes in which chromatin is condensed and increasingly fragmented, revealed as small structure in the nucleus. The membrane shrinks and the cell becomes dense as can be seen by flow cytometry. Interestingly, similar modes of cell deletion were observed in nematodes indicating that apoptosis is a highly conserved machinery. Three Caeonorhabditis elegans gene products are found to have high homology with mammalian apoptotic genes: CED-9 inhibits apoptosis and is related to bcl-2; CED-3 and CED-4 promote apoptosis and are related to caspase 9 and APAF-1. Apoptosis is not accidental death, but a highly controlled and medically important molecular process. More general terms such as 'physiological' or 'regulated' cell death cover different morphologies and sequences. Programmed suicide of cells that were subjected to toxic exogenous and endogenous stimuli plays a key role in understanding cancer development and its treatment. Apoptosis involves sequences of events that may overlap and play contradictory or antagonistic roles in cell death. Generally, the ability to trigger apoptotic processes in cancer cells would benefit an organism by keeping homeostasis intact. Programmed cell death is a regularly present mechanism, for instance, in lymphocyte recruitment in the thymus where immature lymphocytes may recognize host antigens. Therefore, such lymphocytes become apoptotic and are removed by macrophages. Removal prevents possible autoimmune diseases. Unlike apoptosis, necrosis is a passive process of cell death recognizable by membrane morphological changes and accompanied by leakage of intracellular material into intercellular space that may cause inflammation in the organism. Signals that may initiate apoptosis are generally classified into two groups: signals that launch extrinsic apoptotic pathways starting with aggregation of death receptors and intrinsic apoptotic pathways starting with disruption of intracellular homeostasis such as the release of mitochondrial factors or DNA degradation. Early in the process, apoptotic signals may lead to a broad range of signaling mechanisms such as DNA repair and assessment of DNA damage (check points). Thus, failure in any of these steps can cause a defective apoptotic response that plays a decisive role in both tumorigenesis and drug resistance in tumor treatment. More distinctly, the capability of cancer cells to go into apoptosis prevents further neoplastic changes. Generally, the purpose of this study is to investigate the balance between formation of genomic damage and induction of apoptosis under genotoxic stress. After genotoxic insult there are different possibilities for the fate of a cell (Figure 1). The genomic integrity is analyzed at cellular checkpoints, usually leading to a delay in cell cycle progression if DNA was damaged. Mutations in genes such as p53 and p21 change the cellular response to genotoxic stress and may alter the balance between apoptosis and genomic damage. However, p53 is usually mutated or not expressed in 70\% of human tumors. Alterations in p53 states that reflect distinct apoptotic response upon induction of DNA damage were examined. In this study, three cell lines with distinct p53 states were used: TK6 harboring wild-type p53, WTK1 with mutated p53 and NH32 with knocked out p53. In the present work we applied different approaches to investigate the correlation between DNA damage and apoptotic responsiveness in cancer cell lines with different p53 states or in hormone responsive cell lines with over expressed bcl-2 gene. We were focused on effects caused by temporary down regulation of the p53 and Bcl-2 activity in human lymphoblastoid cell lines. In addition, we investigated the impact of estradiol-induced proliferation on apoptosis and DNA damage in stably transfected cells with bcl-2gene.},
  subject      = {Apoptosis},
  language  = {en}
}
@phdthesis{Mueck2004,
  author    = {M{\"u}ck, Alexander},
  title     = {The standard model in 5D : theoretical consistency and experimental constraints},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10591},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The four-dimensional Minkowski space is known to be a good description for space-time down to the length scales probed by the latest high-energy experiments. Nevertheless, there is the viable and exciting possibility that additional space-time structure will be observable in the next generation of collider experiments. Hence, we discuss different extensions of the standard model of particle physics with an extra dimension at the TeV-scale. We assume that some of the gauge and Higgs bosons propagate in one additional spatial dimension, while matter fields are confined to a four-dimensional subspace, the usual Minkowski space. After compactification on an S^1/Z_2 orbifold, an effective four-dimensional theory is obtained where towers of Kaluza-Klein (KK) modes, in addition to the standard model fields, reflect the higher-dimensional structure of space-time. The models are elaborated from the 5D Lagrangian to the Feynman rules of the KK modes. Special attention is paid to an appropriate generalization of the Rxi-gauge and the interplay between spontaneous symmetry breaking and compactification. Confronting the observables in 5D standard model extensions with combined precision measurements at the Z-boson pole and the latest data from LEP2, we constrain the possible size R of the extra dimension experimentally. A multi-parameter fit of all relevant input parameters leads to bounds for the compactification scale M=1/R in the range 4-6 TeV at the 2 sigma confidence level and shows how the mass of the Higgs boson is correlated with the size of an extra dimension. Considering a future linear e+e- collider, we outline the discovery potential for an extra dimension using the proposed TESLA specifications as an example. As a consistency check for the various models, we analyze Ward identities and the gauge boson equivalence theorem in W-pair production and find that gauge symmetry is preserved by a complex interplay of the Kaluza-Klein modes. In this context, we point out the close analogy between the traditional Higgs mechanism and mass generation for gauge bosons via compactification. Beyond the tree-level, the higher-dimensional models studied extensively in the literature and in the first part of this thesis have to be extended. We modify the models by the inclusion of brane kinetic terms which are required as counter terms. Again, we derive the corresponding 4D theory for the KK towers paying special attention to gauge fixing and spontaneous symmetry breaking. Finally, the phenomenological implications of the new brane kinetic terms are investigated in detail.},
  subject      = {Standardmodell <Elementarteilchenphysik>},
  language  = {en}
}
@phdthesis{Murso2004,
  author    = {Murso, Alexander},
  title     = {Electronic response of phosphorus and nitrogen based ligands on metal coordination},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10397},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Phosphorus and nitrogen containing ligands were examined in terms of their coordination flexibility. Combining these donor atoms of different hardness or softness in one molecule leads to the design of polyfunctional, ambidentate ligand systems with unique properties, because the different features associated with each donor atom confer unique reactivity to their metal complexes. The phosphane Ph2P(CH2Py) (Py = 2-pyridyl) is a very versatile starting material for the preparation of highly flexible, hemilabile, ambident ligands. C-deprotonation of this phosphane yields a Janus head, responding very sensitive to the Lewis-acidity and the charge concentration of the coordinated metal, adapting its coordination mode to the electronic requirements of the cation (electronic differentiation). Thus, bidentate (P,N)-chelating, tridentate (P,N)-chelating together with C-coordination and (C,N)-coordination is observed in the different metal complexes discussed in this work. Additionally, the oxidized derivative of the abovementioned phosphane, the iminophosphorane Ph2P(CH2Py)(NSiMe3), is discussed. The C-deprotonated anion of this iminophosphorane prefers (N,N')-side arm- rather than C-coordination. The electron deficient pyridyl substituent at the C-atom leads to charge delocalization in the anionic [Ph2P(CHPy)(NSiMe3]-moiety. The bonding parameters of the iminophosphorane and all its derivatives, together with the almost fixed 15N-NMR resonances for the imino nitrogen atoms in these compounds prove that hypervalent central phosphorus is not required to describe the bonding situation in iminophosphoranes.},
  subject      = {Phosphane},
  language  = {en}
}
@phdthesis{Dobrawa2004,
  author    = {Dobrawa, Rainer Anton},
  title     = {Synthesis and characterization of terpyridine-based fluorescent coordination polymers},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10367},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Complexation properties of 2,2':6',2''-terpyridine (tpy) have been studied with a series of first row transition metal ions by UV-vis, 1H NMR and isothermal titration calorimetry and ƒ´H values for the tpy complexation processes have been determined. These studies reveal that Zn2+ is the best suited metal ion for the reversible coordination of the terpyridine ligand. Thus, supramolecular coordination polymerization of perylene bisimide fluorophores containing terpyridine functionalities have been investigated by using Zn2+ as metal ion. The formation of the dimeric complexes in the case of monotopic model comounds and coordination polymerization of ditopic functional building blocks have been confirmed by 1H NMR studies. The optical properties of dimeric and polymeric complexes have been investigated by UV-vis and fluorescence spectroscopy. The Zn2+ coordination to the terpyridine unit does not effect the advantageous fluorescence properties of perylene bisimide moieties. The reversibility of the formation of coordination polymers has been established by 1H NMR and additionally by DOSY NMR and fluorescence anisotropy measurements. Coordination polymer strands can be visualized by atomic force microscopy (AFM), which also reveals the formation of an ordered monolayer film at higher concentration. The average polymer length has been determined by AFM to 15 repeat units, which correlates well with the value estimated by 1H NMR to >10 repeat units.},
  subject      = {Terpyridinderivate <2},
  language  = {en}
}
@phdthesis{Nuernberger2004,
  author    = {N{\"u}rnberger, Dieter},
  title     = {The Galactic Starburst Region NGC 3603 : exciting new insights on the formation of high mass stars},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10440},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {One of the most fundamental, yet still unsolved problems in star formation research is addressed by the question "How do high mass stars form?". While most details related to the formation and early evolution of low mass stars are quite well understood today, the basic processes leading to the formation of high mass stars still remain a mystery. There is no doubt that low mass stars like our Sun form via accretion of gas and dust from their natal environment. With respect to the formation of high mass stars theorists currently discuss two possible scenarios controversely: First, similar to stars of lower masses, high mass stars form by continuous (time variable) accretion of large amounts of gas and dust through their circumstellar envelopes and/or disks. Second, high mass stars form by repeated collisions (coalescence) of protostars of lower masses. Both scenarios bear difficulties which impose strong constrains on the final mass of the young star. To find evidences for or against one of these two theoretical models is a challenging task for observers. First, sites of high mass star formation are much more distant than the nearby sites of low mass star formation. Second, high mass stars form and evolve much faster than low mass star. In particular, they contract to main sequence, hydrogen burning temperatures and densities on time scales which are much shorter than typical accretion time scales. Third, as a consequence of the previous point, young high mass stars are usually deeply embedded in their natal environment throughout their (short) pre-main sequence phase. Therefore, high mass protostars are rare, difficult to find and difficult to study. In my thesis I undertake a novel approach to search for and to characterize high mass protostars, by looking into a region where young high mass stars form in the violent neighbourhood of a cluster of early type main sequence stars. The presence of already evolved O type stars provides a wealth of energetic photons and powerful stellar winds which evaporate and disperse the surrounding interstellar medium, thus "lifting the courtains" around nearby young stars at a relatively early evolutionary stage. Such premises are given in the Galactic starburst region NGC 3603. Nevertheless, a large observational effort with different telescopes and instruments -- in particular, taking advantage of the high angular resolution and high sensitivity of near and mid IR instruments available at ESO -- was necessary to achieve the goals of my study. After a basic introduction on the topic of (high mass) star formation in Chapter 1, a short overview of the investigated region NGC 3603 and its importance for both galactic and extragalactic star formation studies is given in Chapter 2. Then, in Chapter 3, I report on a comprehensive investigation of the distribution and kinematics of the molecular gas and dust associated with the NGC 3603 region. In Chapter 4 I thoroughly address the radial extent of the NGC 3603 OB cluster and the spatial distribution of the cluster members. Together with deep Ks band imaging data, a detailed survey of NGC 3603 at mid IR wavelengths allows to search the neighbourhood of the cold molecular gas and dust for sources with intrinsic mid IR excess (Chapter 5). In Chapter 6 I characterize the most prominent sources of NGC 3603 IRS 9 and show that these sources are bona-fide candidates for high mass protostars. Finally, a concise summary as well as an outlook on future prospects in high mass star formation research is given in Chapter 7.},
  subject      = {Starburst-Galaxie},
  language  = {en}
}
@phdthesis{Luo2004,
  author    = {Luo, Qin},
  title     = {Essential features of a PrfA-dependent : promoter of Listeria monocytogenes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10341},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The gram-positive, facultative intracellular pathogen Listeria monocytogenes is the causal agent of listeriosis. Most of well-known virulence genes are controlled by PrfA that belongs to the Crp-Fnr family of transcriptional activators. A PrfA-mediated transcription initiating at a virulence gene promoter, inlC promoter (PinlC) that regulates the expression of the small, secreted internalin C, was in-depth characterized by an in vitro transcription system to unravel the essential features of a PrfA-dependent promoter in this study. The obtained results indicate a dual promoter for inlC that leads to PrfA-dependent and -independent transcription in vitro and in vivo. The PrfA-dependent transcription requires, as expected, the PrfA-box, a conserved 14 bp sequence of dyad symmetry located about 40 bp upstream of the transcriptional start site of each PrfA-regulated gene. Another important structural feature for this PrfA-dependent promoter is the distance between the 3´-end of the PrfA-box and the 5´-end of the SigA-recognized -10 box fixed to 22 or 23 bp, which is observed in the interspace regions of the other known PrfA-dependent promoters, e.g. PactA, PplcA, Phly and Pmpl. The -35 box of PinlC is not necessary for PrfA-dependent transcription. The -10 box of PinlC and also that of the other PrfA-dependent promoters of L. monocytogenes closely resemble SigA-recognized -10 promoter sequences of the well-characterized gram-positive bacterium B. subtilis. Even the extended -10 motif (5´-TRTG-3´) considered to be a basic element for many SigA-recognized promoters in B. subtilis is present in PinlC. Primer extension studies reveal that both the PrfA-dependent and the independent promoter share the same -10 box. The PrfA-independent transcription of inlC depends on a -35 box located directly downstream of the PrfA-box, and the close proximity of the two sites inhibits strongly the transcription activity of the PrfA-independent promoter when the PrfA-RNA polymerase complex binds to the PrfA-box. Deletion of the PrfA-box results in PrfA-independent transcription from PinlC, which is no longer inhibited by PrfA. High concentration of GTP appears to be necessary for PrfA-dependent transcription initiated at the inlC promoter and at other PrfA-dependent promoters. Based on transcriptome analysis, Milohanic and his co-workers identified three groups of genes that were regulated differently by PrfA. Some of these genes containing putative PrfA-boxes in their 5´-upstream regulatory regions were selected for analysis of their transcriptional dependency on PrfA using again the in vitro transcription system. The data show that among these "PrfA-regulated" promoters tested, only the promoter of the hpt gene belonging to group I is clearly activated by PrfA. This promoter is also the only one that exhibited all essential features of a typical PrfA-dependent promoter as described above. In vitro transcription starting at most of the other promoters was neither positively nor negatively affected by PrfA. Transcription initiated at some of the promoters of group III genes (lmo0596 and lmo2067) is rather inefficient with SigA-loaded RNA polymerase, but is highly activated with RNA polymerase loaded with purified SigB. Addition of purified PrfA protein has no effect on the SigB-dependent transcription. These in vitro transcription results indicate that the in vivo observed PrfA effect on the expression of most of the new genes is either indirect or PrfA-mediated transcription of these genes requires - in contrast to the PrfA-dependent transcription of the known virulence genes (including hpt) - additional factors not present in the in vitro transcription assay. In addition to these new genes described by Milohanic, the promoters of two genes (lmo2420 and lmo2840) that contain putative PrfA-boxes with only a single mismatch in their upstream regulatory regions were analyzed in this study. However, transcription of none of these genes is regulated by PrfA, suggesting that these genes are either not truly regulated by PrfA or regulated by other global transcription activators that interact with PrfA by yet unknown mechanisms. By exchanging corresponding sequences between a functionally inactive promoter ParoAP2 and a typical PrfA-dependent promoter PplcA, it is found that PrfA-dependent in vitro transcription can be initiated from the hybrid promoter containing the putative PrfA-box and the SigA-recognized -10 box (TTTAAT) from the putative PrfA-dependent aroAP2 promoter, but it is inhibited strongly by the interspace sequence between these two sites apparently due to an additional RNA polymerase binding site [the -10 box (TAATAT) for the PrfA-independent transcription of ParoAP1)] within this region. Furthermore, a symmetric sequence downstream of the -10 box (TTTAAT) is also shown to be a strongly inhibitory for PrfA-dependent transcription from the putative PrfA-dependent aroAP2 promoter.},
  subject      = {Listeria monocytogenes},
  language  = {en}
}
@phdthesis{Schallenberg2004,
  author    = {Schallenberg, Timo},
  title     = {Shadow mask assisted heteroepitaxy of compound semiconductor nanostructures},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10290},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Shadow Mask assisted Molecular Beam Epitaxy (SMMBE) is a technique enabling selected area epitaxy of semiconductor heterostructures through shadow masks. The objective of this work was the development of the SMMBE technique for the reliable fabrication of compound semiconductor nanostructures of high structural and optical quality. In order to accomplish this, technological processes have been developed and optimized. This, in combination with model calculations of the basic kinetic growth processes has enabled the fabrication of high quality quantum structures. A high spatial precision and control of the incidence regions of the molecular beams during the SMMBE process are required for the fabrication of nanostructures. One of the technological developments to this effect, which has substantially enhanced the versatility of SMMBE, is the introduction of a new type of freestanding shadow masks: Growth through such a mask with different incidence angles of the molecular beams is equivalent to employing different mechanical masks, but is much more accurate since the precision of mechanical alignment is limited. A consistent model has been developed, which successfully explains the growth dynamics of molecular beam epitaxy through shadow masks. The redistribution of molecular fluxes under shadow masks may affect the growth rates on selected areas of the substrate drastically. In the case of compound semiconductors, reactions between the constituent species play important roles in controlling the growth rates as a function of the growth parameters. The predictions of the model regarding the growth of II-VI and III-V compounds have been tested experimentally and the dependence of the growth rates on the growth parameters has been verified. Moreover, it has been shown, that selected area epitaxy of II-VI and III-V compounds are governed by different surface kinetics. Coexisting secondary fluxes of both constituent species and the apparent non-existence of surface diffusion are characteristic for SMMBE of II-VI compounds. In contrast, III-V SMMBE is governed by the interplay between secondary group-V flux and the surface migration of group-III adatoms. In addition to the basic surface kinetic processes described by the model, the roles of orientation and strain-dependent growth dynamics, partial shadow, and material deposition on the mask (closure of apertures) have been discussed. The resulting advanced understanding of the growth dynamics (model and basic experiments) in combination with the implementation of technical improvements has enabled the development and application of a number of different processes for the fabrication of both II-VI and III-V nanostructures. In addition to specific material properties, various other phenomena have been exploited, e.g., self-organization. It has been shown that, e.g., single quantum dots and quantum wires can be reliably grown. Investigations performed on the SMMBE nanostructures have demonstrated the high positional and dimensional precision of the SMMBE technique. Bright cathodoluminescence demonstrates that the resulting quantum structures are of high structural and optical quality. In addition to these results, which demonstrate SMMBE as a prospective nanofabrication technique, the limitations of the method have also been discussed, and various approaches to overcome them have been suggested. Moreover, propositions for the fabrication of complex quantum devices by the multiple application of a stationary shadow mask have been put forward. In addition to selected area growth, the shadow masks can assist in etching, doping, and in situ contact definition in nanoscale selected areas. Due to the high precision and control over the dimensions and positions of the grown structures, which at the same time are of excellent chemical, crystal, and optical quality, SMMBE provides an interesting perspective for the fabrication of complex quantum devices from II-VI and III-V semiconductors.},
  subject      = {Verbindungshalbleiter},
  language  = {en}
}
@phdthesis{Krampert2004,
  author    = {Krampert, Gerhard},
  title     = {Femtosecond quantum control and adaptive polarization pulse shaping},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10304},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Adaptive Femtosekunden-Quantenkontrolle hat sich in den letzten Jahren als eine sehr erfolgreiche Methode in vielen wissenschaftlichen Gebieten wie Physik, Chemie oder Biologie erwiesen. Eine Vielzahl von Quantensystemen und insbesondere Molek{\"u}le, die eine chemische Reaktion durchlaufen, sind durch speziell geformte, Femtosekunden-Laserimpulse kontrolliert worden. Diese Methode erlaubt es, nicht nur das Quantensystem zu beobachten, sondern einen Schritt weiterzugehen und aktive Kontrolle {\"u}ber quantenmechanische Dynamik zu erlangen. In diesem Schema werden Interferenzph{\"a}nomene im Zeit- und Frequenzraum benutzt, um Selektivit{\"a}t zum Beispiel in einer chemischen Reaktion zu erhalten. Die dazu benutzten, speziell geformten Femtosekunden-Laserimpulse waren bislang nur linear polarisiert. Deshalb konnten sie nur die skalaren Eigenschaften der Licht - Materie - Wechselwirkung ausnutzen und haben so den vektoriellen Charakter des elektrischen Dipolmoments \$\vec{\mu}\$ und des elektrischen Lichtfeldes \$\vec{E}(t)\$ vernachl{\"a}ssigt. Im besonderen in der Quantenkontrolle von chemischen Reaktionen ist das untersuchte System, die Molek{\"u}le, dreidimensional und zeigt komplexe raumzeitliche Dynamik. Mit der Hilfe von polarisations-geformten Laserimpulsen ist man jetzt in der Lage dieser Dynamik, sowohl in der Zeit als auch in der r{\"a}umlichen Richtung zu folgen. Deshalb kann nun ein neues Niveau an Kontrolle in quanten-mechanischen Systemen erreicht werden. In dieser Arbeit konnte die Erzeugung von polarisations-geformten Laserimpulsen in einem optischen Aufbau verwirklicht werden. Dieser Aufbau erfordert keine interferometrische Stabilit{\"a}t, da beide Polarisationskomponenten demgleichen Strahlweg folgen. Zwei-Kanal spektrale Interferometrie wurde eingesetzt, um die Laserimpulse experimentell vollst{\"a}ndig zu charakterisieren. Um den zeitabh{\"a}ngigen Polarisationszustand dieser Pulse exakt zu beschreiben, wurde eine mathematische Darstellung entwickelt und angewandt. Die Ver{\"a}nderungen des Polarisationszustandes durch optische Elemente wurde untersucht und einige L{\"o}sungen wurden aufgezeigt, um diese Ver{\"a}nderungen zu minimieren. Der Jones Matrix Formalismus wurde dazu benutzt, alle Verzerrungen des Polarisationszustandes zwischen dem Impulsformer und dem Ort des Experiments zu ber{\"u}cksichtigen. Zugleich k{\"o}nnen die Jones Matrizen zu einer vollst{\"a}ndigen Charakterisierung der erzeugten Laserimpulse verwendet werden. Dabei wurden experimentell kalibrierte Matrizen eingesetzt. Adaptive Polarisations-Impulsformung konnte in einem rein optischen Demonstrationsexperiment gezeigt werden. Dabei wurde die computergesteuerte Polarisationsformung mit einer Lernschleife und einem experimentellen R{\"u}ckkopplungssignal kombiniert. Durch diesen selbstlernenden Algorithmus konnte der ben{\"o}tigte, linear polarisierte Laserimpuls mit m{\"o}glichst kleiner Impulsdauer gefunden werden, der f{\"u}r die effektive Erzeugung der zweiten Harmonischen in einem nichtlinearen optischen Kristall am besten geeignet ist. Durch diese R{\"u}ckkopplungsschleife war es m{\"o}glich auch noch kompliziertere Polarisationsverzerrungen, die durch eine Wellenplatte f{\"u}r eine falsche Wellenl{\"a}nge verursacht wurden, r{\"u}ckg{\"a}ngig zu machen. Die zus{\"a}tzliche Verformung der spektralen Phase durch Materialdispersion in einem 10~cm langen Glasblock konnte ebenfalls automatisch kompensiert werden. Nach diesen optischen Demonstrationsexperimenten wurde ultraschnelle Polarisationsformung angewandt, um ein Quantensystem zu kontrollieren. Die Polarisationsabh{\"a}ngigkeit der Multi-Photonen Ionisation von Kaliumdimeren konnte in einer Anrege-Abtast Messung nachgewiesen werden. Diese Abh{\"a}ngigkeit wurde dann in einem adaptiven Polarisationsformungsexperiment in einer sehr viel allgemeineren Art ausgenutzt. Statt nur einem Anrege- und Abtastlaserimpuls mit jeweils unterschiedlicher Polarisation zu benutzen, wurde der zeitabh{\"a}ngige Polarisationszustand eines geformtem Laserimpulses benutzt, um die Ionisation zu maximieren. Anstelle von einer nur quantitativen Verbesserung konnte eine qualitativ neue Art von Kontrolle {\"u}ber Quantensysteme demonstriert werden. Diese Polarisationskontrolle ist anwendbar selbst bei zuf{\"a}llig ausgerichteten Molek{\"u}len. Durch diese M{\"o}glichkeit, auf Ausrichtung der Molek{\"u}le zu verzichten, konnte mit einem wesentlich vereinfachten experimentellen Aufbau gearbeitet werden. {\"U}ber diese Polarisationskontrollexperimente hinaus wurden auch die dreidimensionalen Aspekte der Dynamik von Molek{\"u}len erforscht und kontrolliert. Die \textit{cis-trans} Photoisomerisierungsreaktion von 3,3\$'\$-Diethyl-2,2\$'\$-Thiacyanin Iodid (NK88) wurde in der fl{\"u}ssigen Phase mit transienter Absorptionsspektroskopie untersucht. Die Isomerisierungsausbeute konnte sowohl erh{\"o}ht als auch erniedrigt werden durch den Einsatz geformter Femtosekunden-Laserimpulse mit einer Zentralwellenl{\"a}nge von 400~nm, die sowohl in spektraler Phase als auch Amplitude moduliert waren. Dieses Experiment zeigt die M{\"o}glichkeit, die koh{\"a}rente Bewegung großer molekularer Gruppen durch Laserimpulse gezielt zu beeinflussen. Diese Modifikation der molekularen Geometrie kann als erster Schritt angesehen werden, kontrollierte Stereochemie zu verwirklichen. Insbesondere da im ersten Teil dieser Arbeit die Kontrolle von Molek{\"u}len mit Polarisations-geformten Impulsen gezeigt werden konnte, ist der Weg geebnet zu einer Umwandlung von einem chiralen Enantiomer in das andere, da theoretische Modelle dieser Umwandlung polarisations-geformte Laserimpulse ben{\"o}tigen. Außer diesen faszinierenden Anwendungen der Polarisationsformung sollte es nun m{\"o}glich sein den Wellenl{\"a}ngenbereich der polarisations-geformten Laserimpulse auszuweiten. Sowohl Erzeugung der zweiten Harmonischen um in den ultravioletten Bereich zu kommen als auch optische Gleichrichtung von {\"a}ußerst kurzen Femtosekunden-Impulsen um den mittleren infrarot Bereich abzudecken sind M{\"o}glichkeiten, den Wellenl{\"a}ngenbereich von polarisations-geformten Laserimpulsen zu erweitern. Mit diesen neuen Wellenl{\"a}ngen tut sich eine Vielzahl an neuen M{\"o}glichkeiten auf, Polarisationsformung f{\"u}r die Kontrolle von quantenmechanischen Systemen einzusetzen.},
  subject      = {Ultrakurzer Lichtimpuls},
  language  = {en}
}
@phdthesis{Reintjes2004,
  author    = {Reintjes, Norbert},
  title     = {Taxonomy, faunistics and life-history traits of Dytiscidae and Noteridae (Coleoptera) in a West African savannah},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10287},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The studies inventoried the species of the families Dytiscidae and Noteridae (Coleoptera) in Como{\´e} National Park in northern Ivory Coast, West Africa and investigated the ecological role of temporary and permanent water bodies for the aestivation of these aquatic beetles. The ecological studies focused on the question how the beetles cope with the temporary loss of their aquatic habitats during dry season. The climate in the study area is characterised by a pronounced dry season from about November to March/April, in which the temporary ponds and creeks in the savannah entirely desiccate. The only available water bodies during dry season in Como{\´e} National Park are the Como{\´e} River, pools in some of its tributaries, and a few of the large savannah ponds. The taxonomic and faunistic analysis revealed a high species richness in the study area and yielded a total of twelve species of Noteridae in four genera and 95 species of Dytiscidae in 22 genera. Thirty of these species had not yet been reported from the Ivory Coast. A description of a new species in the genus Laccophilus is given, named L. comoensis in honour of the National Park. Strong incidences exist that the material includes more species yet unknown to science. Concerning the mode of aestivation, observations in pilot studies led to the working hypothesis that the beetles pass the dry season as adults in aquatic habitats. Consequently, presence of adults in aquatic habitats throughout the dry season and cyclic migration of adults between temporary and permanent water bodies was expected. Regular sampling of water bodies throughout the dry season and beginning rainy season yielded 33,705 individuals in 72 species and 26 genera. In all the sample periods Noteridae and / or Dytiscidae were recorded. The number of species per period was between 36 and 58. It is concluded that in Como{\´e} National Park a) at least parts of the populations of the recorded species pass the dry season as adults and b) aquatic habitats serve as a refuge for aestivation of these adult beetles. In a rocky area in the riverbed of the permanent Como{\´e} River four sets of studies were performed during dry and beginning rainy season. According to the working hypothesis beetles should be searching for adequate aquatic habitats as long as temporary savannah waters are becoming inhospitable and are falling dry. Seven rock pools in the riverbed of the Como{\´e} River were artificially filled and thus offered for colonization at the peak of the dry season (end of January). After five days the rock pools were quantitatively sampled by completely emptying them. All the rock pools were colonized by Dytiscidae and / or Noteridae and with a total of 1,507 individuals in 26 species abundance and diversity were high. Habitats for aestivation are needed most, when the majority of the savannah waters are fallen dry. Little precipitation on February 18th 1999 had filled rock pools in the riverbed of the Como{\´e} River but no pools in the savannah, where the rain was immediately absorbed by the very dry soil. An inventory of beetles was performed in 21 naturally filled rock pools five to 20 days after this precipitation. The sampling yielded 8,456 individuals in 41 species. Except the smallest, all rock pools contained beetles. The result showed that Dytiscidae and Noteridae utilise the rock pools as aquatic habitat during dry season. Beetles adapted to a highly seasonal environment like the aquatic system in the study area should be good colonizers. Sampling of four, respectively five rock pools at two occasions within 24 hours after the start of precipitation examined the potential of colonizers at that period (March). Prior to these precipitations the pools had been completely dry. Dytiscidae were already present in all rock pools and a total of 434 Dytiscidae in 14 species was found. The working hypothesis of cyclic migration suggests that the beetles should leave the rock pools at the onset of the rainy season when precipitation had filled temporary water bodies in the savannah. After several precipitation events an inventory of 13 rock pools of the Como{\´e} River in May controlled for adult beetles. Only four species with 126 individuals were still found, of which Yolina chopardi contributed 81.7\%. This species seems to differ from the other recorded species in the use of habitats, since it was never recorded in the savannah. In general, however, diversity and abundance of Dytiscidae and Noteridae in the rock pools, as expected, was low after the onset of the rainy season. During the entire study of the rock pools in the riverbed of the Como{\´e} River 10,523 individuals in 44 species and 18 genera were collected. Thus, more than half of the species recorded in Como{\´e} National Park were found in the rock pools. The results suggest that the Como{\´e} River and the rock pools in the riverbed serve as aquatic retreat for adult Dytiscidae and Noteridae during dry season when temporary water bodies in the savannah are desiccated. The suggested cyclic migration between water bodies predicts that newly formed savannah waters are recolonized by the beetles at the onset of the rainy season. This colonization should be a) by adults and b) airborne. Two artificial ponds in the open savannah were offered only for aerial colonization at the beginning of the rainy season. The ponds were controlled for adult Noteridae and Dytiscidae daily during one continuous phase of eleven and a second one of 16 days (end of March to end of April). On every sampling date Noteridae or Dytiscidae were recorded. In the entire study 2,744 individuals in 44 species and 16 genera were collected. After precipitation, abundance and species richness increased. Thirty-five of the encountered species had been recorded in rock pools of the Como{\´e} River before. The principal species in the artificial savannah ponds had been principal species in samplings of the rock pools as well. The results support the hypothesis of cyclic migration: most species of Dytiscidae and Noteridae of the Como{\´e} National Park fly from desiccating savannah waters to permanent water bodies or water bodies holding water for extended times during dry season. They pass the dry season in these waters and fly back into the savannah after precipitation at the onset of the rainy season. Exceptions from this general rule are discussed.},
  subject      = {Schwimmk{\"a}fer},
  language  = {en}
}
@phdthesis{Redelbach2004,
  author    = {Redelbach, Andreas},
  title     = {SUSY Seesaw model and phenomenological implications for leptonic processes at low energies and leptogenesis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10182},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In this work the supersymmetric seesaw model and its effects on low-energy leptonic observables and thermal leptogenesis have been systematically investigated. Precision measurements will increase the sensitivity on lepton-flavor violating decays, particularly on Br(l_j->l_i gamma) and also on electric and magnetic dipole moments in the near future. In order to improve also the accuracy of theoretical predictions for these processes, we have performed a full one-loop calculation of the underlying supersymmetric processes taking into account the lepton masses. Since the mechanism of soft supersymmetry breaking (SSB) is completely unknown, a novel analysis beyond the often studied minimal Supergravity scenarios has been performed. This way it has been demonstrated that in the considered mSUGRA, AMSB, GMSB and gaugino mediated scenarios, the ongoing search for Br(mu->e gamma) can constrain fundamental SSB parameters and/or the seesaw parameters. On the other hand, the basic parameters of thermal leptogenesis, such as the CP asymmetry in the decays of the lightest right-handed Majorana neutrino, provide probes of the unknown complex orthogonal R-matrix of the seesaw model.},
  subject      = {Supersymmetrie},
  language  = {en}
}
@phdthesis{Hein2004,
  author    = {Hein, Silke},
  title     = {The survival of grasshoppers and bush crickets in habitats variable in space and time},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9140},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Die zunehmende Nutzung von Landschaften f{\"u}hrt zu einer steigenden Fragmentierung sch{\"u}tzenswerter Fl{\"a}chen. Damit verbunden ist eine Zerschneidung von großen Populationen in Metapopulationen. In solchen F{\"a}llen bestimmt das Gleichgewicht zwischen Aussterben und Besiedlung von Habitaten die regionale {\"U}berlebenswahrscheinlichkeit von Arten. Um diese bestimmen, braucht man ein gutes Verst{\"a}ndnis der Habitatanspr{\"u}che der Arten, sowie Informationen {\"u}ber ihr Ausbreitungsverhalten. Ziel dieser Arbeit war es, geeignete Fl{\"a}chen f{\"u}r Heuschrecken in einer Landschaft identifizieren zu k{\"o}nnen, sowie einen Beitrag zur Quantifizierung der Erreichbarkeit einzelner Fl{\"a}chen durch Individuen zu leisten. Der erste Teil dieser Arbeit besch{\"a}ftigt sich mit der Quantifizierung der Habitateignung von Fl{\"a}chen f{\"u}r Heuschrecken. Dazu habe ich statistische Habitateignungsmodelle mittels logistischer Regression erstellt, evaluiert und validiert. Es zeigte sich, dass die Habitatwahl der Heuschrecken auf einer mittleren r{\"a}umlichen Skalenebene erfolgt. Dies steht mit der beobachteten Ausbreitungsdistanz der Tiere im Einklang. Neben dem nur grob klassifizierten Landschaftsfaktor „Biotoptyp" korrelieren vor allem strukturelle Faktoren sowie abiotische Faktoren mit dem Vorkommen der Heuschreckenarten. Bei der Bestimmung eines gemeinsamen Models f{\"u}r alle drei Heuschreckenarten erwies sich das Model der Art S. lineatus mit den Parametern Biotoptyp und Vegetationsh{\"o}he als am besten geeignet zur Vorhersage der Vorkommen der anderen Heuschreckenarten. Um zu testen, ob auch die Vorkommen von Arten unterschiedlicher Tiergruppen mittels eines gemeinsamen Modells vorhergesagt werden k{\"o}nnen, habe ich sowohl die Heuschreckenmodelle zur Prognose von Faltervorkommen getestet, als auch Modelle f{\"u}r Falter auf Heuschrecken {\"u}bertragen. Dabei erwiesen sich die Heuschreckenmodelle zur Prognose der anderen Arten weniger geeignet als das Modell f{\"u}r das Widderchen Z. carniolica in das der Anteil an geeignetem Habitat sowie die Vorkommen der beiden Saugpflanzen C. jacea und S. columbaria einfließen. Diese Art wird als standorttreu eingestuft und repr{\"a}sentiert damit auch die anderen Arten, die typisch f{\"u}r S{\"a}ume und Halbtrockenrasen sind. Die erh{\"o}hte Mobilit{\"a}t von Z. carniolica im Vergleich zu den Heuschrecken garantiert gleichzeitig auch die Erreichbarkeit aller geeigneten Fl{\"a}chen im Gebiet und damit ein Modell, das nur unwesentlich durch Zufallseffekte bei der Besiedlung beeinflusst wird. Neben der Habitatqualit{\"a}t/-quantit{\"a}t spielt vor allem der Austausch zwischen Fl{\"a}chen eine entscheidende Rolle f{\"u}r das {\"U}berleben der Metapopulation. Im zweiten Teil meiner Arbeit habe ich mich sowohl theoretisch als auch empirisch, mit dem Ausbreitungsverhalten von Heuschrecken besch{\"a}ftigt. In Freilandexperimenten konnte ich zeigen, dass die Annahme eines dichotomen Bewegungsverhaltens f{\"u}r Heuschrecken in einer realen Landschaft nicht zutrifft. Vielmehr wird die Bewegung in einer Fl{\"a}che besser als Kontinuum beschrieben das durch strukturelle Resistenz, Temperatur, Mortalit{\"a}tsrisiko und Ressourcenverf{\"u}gbarkeit bestimmt wird. Die jeweilige Kombination dieser Parameter veranlasst die Tiere dann zu einem entsprechenden Bewegungsmuster, das sich zwischen den beiden Extremen gerichteter und zuf{\"a}lliger Lauf bewegt. In Experimenten zum Grenzverhalten von Heuschrecken best{\"a}tigte sich dieses Ergebnis. F{\"u}r verschiedene Grenzstrukturen konnte ich unterschiedliche {\"U}bertrittswahrscheinlichkeiten nachweisen. Weiterhin konnte ich feststellen, dass Heuschrecken geeignete Habitate aus einer gewissen Entfernung detektieren k{\"o}nnen. Da das Ausbreitungsverhalten von Tieren in theoretischen Modellen eine wichtige Rolle spielt, k{\"o}nnen diese empirischen Daten zur Parametrisierung dieser Modelle verwendet werden. Zus{\"a}tzlich zum Einfluss des Laufmusters der Tiere auf die Erreichbarkeit geeigneter Habitate, zeigte sich in den von mir durchgef{\"u}hrten Simulationsstudien deutlich, dass der landschaftliche Kontext, in dem die Ausbreitung stattfindet, die Erreichbarkeit einzelner Habitate beeinflusst. Dieser Effekt ist zus{\"a}tzlich abh{\"a}ngig von der Mortalit{\"a}tsrate beim Ausbreitungsvorgang. Mit den Ergebnissen aus den Untersuchungen zur Habitateignung lassen sich die f{\"u}r Heuschrecken geeigneten Habitate in einer Landschaft identifizieren. Somit l{\"a}sst sich die potentielle Eignung einer Fl{\"a}che als Habitat, basierend auf Vorhersagen {\"u}ber die {\"A}nderung des Biotoptyps durch ein Managementverfahren, vorhersagen. Diese Information allein reicht aber nicht aus, um die regionale {\"U}berlebenswahrscheinlichkeit einer Art bestimmen zu k{\"o}nnen. Meine Untersuchungen zum Ausbreitungsverhalten zeigen deutlich, dass die Erreichbarkeit geeigneter Fl{\"a}chen von der r{\"a}umlichen Anordnung der Habitate und der Struktur der Fl{\"a}chen, die zwischen Habitaten liegen, abh{\"a}ngt. Zus{\"a}tzlich spielen individuenspezifische Faktoren wie Motivation und physiologische Faktoren eine ausschlaggebende Rolle f{\"u}r die Erreichbarkeit von geeigneten Fl{\"a}chen.},
  subject      = {Naturschutzgebiet Hohe Wann},
  language  = {en}
}
@phdthesis{Hart2004,
  author    = {Hart, Stefan},
  title     = {Characterisation of the molecular mechanisms of EGFR signal transactivation in human cancer},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10067},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In a variety of established tumour cell lines, but also in primary mammary epithelial cells metalloprotease-dependent transactivation of the EGFR, and EGFR characteristic downstream signalling events were observed in response to stimulation with physiological concentrations of GPCR agonists such as the mitogens LPA and S1P as well as therapeutically relevant concentrations of cannabinoids. Moreover, this study reveals ADAM17 and HB-EGF as the main effectors of this mechanism in most of the cancer cell lines investigated. However, depending on the cellular context and GPCR agonist, various different members of the ADAM family are selectively recruited for specific ectodomain shedding of proAR and/or proHB-EGF and subsequent EGFR activation. Furthermore, biological responses induced by LPA or S1P such as migration in breast cancer and HNSCC cells, depend on ADAM17 and proHB-EGF/proAR function, respectively, suggesting that highly abundant GPCR ligands may play a role in tumour development and progression. Moreover, EGFR signal transactivation could be identified as the mechanistic link between cannabinoid receptors and the activation of mitogen activated protein kinases (MAPK) ERK1/2 as well as pro-survival Akt/PKB signalling. Depending on the cellular context, cannabinoid-induced signal cross-communication was mediated by shedding of proAmphiregulin and/or proHB-EGF by ADAM17. Most importantly, our data show that concentrations of THC comparable to those detected in the serum of patients after THC administration accelerate proliferation of cancer cells instead of apoptosis and thereby may contribute to cancer progression in patients.},
  subject      = {Epidermaler Wachstumsfaktor-Rezeptor},
  language  = {en}
}
@phdthesis{Seider2004,
  author    = {Seider, David},
  title     = {Solving an eigenvalue problem in laser simulation},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-10057},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In this thesis a new and powerful approach for modeling laser cavity eigenmodes is presented. This approach is based on an eigenvalue problem for singularly perturbed partial differential operators with complex coefficients; such operators have not been investigated in detail until now. The eigenvalue problem is discretized by finite elements, and convergence of the approximate solution is proved by using an abstract convergence theory also developed in this dissertation. This theory for the convergence of an approximate solution of a (quadratic) eigenvalue problem, which particularly can be applied to a finite element discretization, is interesting on its own, since the ideas can conceivably be used to handle equations with a more complex nonlinearity. The discretized eigenvalue problem essentially is solved by preconditioned GMRES, where the preconditioner is constructed according to the underlying physics of the problem. The power and correctness of the new approach for computing laser cavity eigenmodes is clearly demonstrated by successfully simulating a variety of different cavity configurations. The thesis is organized as follows: Chapter 1 contains a short overview on solving the so-called Helmholtz equation with the help of finite elements. The main part of Chapter 2 is dedicated to the analysis of a one-dimensional model problem containing the main idea of a new model for laser cavity eigenmodes which is derived in detail in Chapter 3. Chapter 4 comprises a convergence theory for the approximate solution of quadratic eigenvalue problems. In Chapter 5, a stabilized finite element discretization of the new model is described and its convergence is proved by applying the theory of Chapter 4. Chapter 6 contains computational aspects of solving the resulting system of equations and, finally, Chapter 7 presents numerical results for various configurations, demonstrating the practical relevance of our new approach.},
  subject      = {Laser},
  language  = {en}
}
@phdthesis{Erdmann2004,
  author    = {Erdmann, Marco},
  title     = {Coupled electron and nuclear dynamics in model systems},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9968},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Subject of this work was to investigate the influence of nonadiabatic coupling on the dynamical changes of electron and nuclear density. The properties of electron density have neither been discussed in the stationary case, nor for excited electronic states or for a coupled electronic and nuclear motion. In order to remove these restrictions one must describe the quantum mechanical motion of all particles in a system at the same level. This is only possible for very small systems. A model system developed by Shin and Metiu [1, 2] contains all necessary physical ingredients to describe a combined electronic and nuclear motion. It consists of a single nuclear and electronic degree of freedom and the particle interaction is parameterized in such a way as to allow for a facile switching between and adiabatic (Born-Oppenheimer type) and a strongly coupled dynamics. The first part of the work determined the "static" properties of the model system: The calculation of electronic eigenfunctions, adiabatic potential curves, kinetic coupling elements and transition dipole moments allowed for a prediction of the coupled dynamics. The potentials obtained from different parameterization showed two distinct cases: In the first case the ground and first excited state are separated by a large energy gap which is the typical Born-Oppenheimer case; the second one exhibits an avoided crossing which results in a breakdown of the adiabatic approximation. Due to the electronic properties of the system, the quantum dynamics in the two distinct situations is very different. This was illustrated by calculating nuclear and electron densities as a function of time. In the Born-Oppenheimer case, the electron density followed the vibrational motion of the nucleus. This was demonstrated in two examples. In the strongly coupled case the wave packet did not exhibit features caused by nonadiabatic coupling. However, projections of the wave function onto the electronic states revealed the usual picture obtained from solutions of the nuclear Schr{\"o}dinger equation involving coupled electronic states. In that case the nuclear motion triggered charge transfer via nonadiabatic coupling. The second part of the work demonstrated that the model system can easily be modified to yield binding situations often found in diatomic molecules. The different situations can be characterized in terms of bound and dissociative adiabatic potential curves. The investigation focussed on the case of an electronic predissociation, where the ground state is dissociative in the asymptotic limit of large internuclear distances. Within our model system we were able to demonstrate how the character of the electron density changes during the fragmentation process. In the third part we investigated the influence of external fields on the correlated dynamics of electron and nucleus. Employing adiabatic potential curves, the structure of absorption spectra can be understood within the weak-field limit. In the above described Born-Oppenheimer case the adiabatically calculated spectrum was in very good agreement with the exact one, whereas in the strongly coupled case the obtained spectrum was not able to resemble the exact one. Regarding the dynamics during a laser excitation process the time-dependent electron and nuclear densities nicely illustrated the famous Franck-Condon principle. The interaction with strong laser pulses lead to an excitation of many bound electronic and vibrational states. The electron density reflected the classical-like quiver motion of the electron induced by the fast variations of the electric field. The nucleus did not follow these fast oscillations because of its much larger mass. The last part of the work extended the original model system by including an additional electron. As a consequence of the Pauli principle, the spatial electronic wave function has to be either symmetric or anti-symmetric with respect to exchange of the two electrons. This corresponds to anti-parallel or parallel electron spins, respectively. The extended model already contains the physical properties of a many-electron system. Solving the time-dependent Schr{\"o}dinger equation for a typical vibrational wave packet motion clearly indicated that the electron density is no longer suited to "localize" single electrons. We extended the definition of the electron localization function (ELF) to an exact, time-dependent wave function and demonstrated, how the ELF can be used to further characterize a coupled electron and nuclear motion. Finally, we gave an outlook of how to define electron localization in the case of anti-parallel electron spins. We derived a quantity similar to the ELF denoted "anti-parallel spin electron localization function" (ALF) and demonstrated that the ALF allows to follow time-dependent changes of the electron localization in a numerical example. [1] S. Shin, H. Metiu, J. Chem. Phys. 1995, 102, 9285. [2] S. Shin, H. Metiu, J. Phys. Chem. 1996, 100, 7867.},
  subject      = {Nichtadiabatischer Prozess},
  language  = {en}
}
@phdthesis{Menth2004,
  author    = {Menth, Michael},
  title     = {Efficient admission control and routing for resilient communication networks},
  doi       = {10.25972/OPUS-846},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9949},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {This work is subdivided into two main areas: resilient admission control and resilient routing. The work gives an overview of the state of the art of quality of service mechanisms in communication networks and proposes a categorization of admission control (AC) methods. These approaches are investigated regarding performance, more precisely, regarding the potential resource utilization by dimensioning the capacity for a network with a given topology, traffic matrix, and a required flow blocking probability. In case of a failure, the affected traffic is rerouted over backup paths which increases the traffic rate on the respective links. To guarantee the effectiveness of admission control also in failure scenarios, the increased traffic rate must be taken into account for capacity dimensioning and leads to resilient AC. Capacity dimensioning is not feasible for existing networks with already given link capacities. For the application of resilient NAC in this case, the size of distributed AC budgets must be adapted according to the traffic matrix in such a way that the maximum blocking probability for all flows is minimized and that the capacity of all links is not exceeded by the admissible traffic rate in any failure scenario. Several algorithms for the solution of that problem are presented and compared regarding their efficiency and fairness. A prototype for resilient AC was implemented in the laboratories of Siemens AG in Munich within the scope of the project KING. Resilience requires additional capacity on the backup paths for failure scenarios. The amount of this backup capacity depends on the routing and can be minimized by routing optimization. New protection switching mechanisms are presented that deviate the traffic quickly around outage locations. They are simple and can be implemented, e.g, by MPLS technology. The Self-Protecting Multi-Path (SPM) is a multi-path consisting of disjoint partial paths. The traffic is distributed over all faultless partial paths according to an optimized load balancing function both in the working case and in failure scenarios. Performance studies show that the network topology and the traffic matrix also influence the amount of required backup capacity significantly. The example of the COST-239 network illustrates that conventional shortest path routing may need 50\% more capacity than the optimized SPM if all single link and node failures are protected.},
  subject      = {Kommunikation},
  language  = {en}
}
@phdthesis{Pyz2004,
  author    = {Pyz, Elwira},
  title     = {Identification of rat NKT cells and molecular analysis of their surface receptor mediated activation},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9767},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Zusammenfassung NKT Zellen wurden urspr{\"u}nglich {\"u}ber die gleichzeitige Expresion eines T-Zellantigenrezeptors (TZR) und den NK-Zellmarkern NKRP1A im Menschen bzw. NK1.1. (NKRP1C) in der Maus definiert. In Mensch und Maus exprimieren die meisten NKT Zellen CD1d restringierte TZR mit charakteristischen Genumlagerungen- Va24JaQ/Vb11 im Menschen und Va14Ja18/Vb8.2 in der Maus. Den NKT Zellen werden außerdem wichtige Funktionen in der „first line defence" und der Immunregulation zugesprochen. Gegenstand der Doktorarbeit war die Charakterisierung eines hypothetischen Gegenst{\"u}ckes in der Ratte. In der Maus wurden rund 30\% der intrahepatischen Lymphozyten (IHL) und 3\% der Milzlymphozyten als CD1d restringierte NK T Zellen identifiziert und konnten mittels a-GalCer beladenen Maus-CD1d Tetramer visualisiert werden. Wie in der Maus wurden in der Ratte NKRP1A+TZR+ Zellen vorwiegend in der Leber gefunden, waren aber f{\"u}nfmal weniger h{\"a}ufig. F344 Ratten NKT Zellen waren dar{\"u}ber hinaus im Gegensatz zu den CD4+ oder CD4-CD8- Maus NKT Zellen meistens CD8 positiv und banden kein mCD1d Tetramer. Da in der menschlichen Leber CD1d-restringierte Va24JQ+ T Zellen ebenfalls viel seltener als in der Maus sind, scheint es nun m{\"o}glich, daß der Ph{\"a}notyp der Ratten NKT Zellen eher dem des Menschen als dem der Maus entspricht. Ein Test der F{\"a}higkeit von F344 Leber- und Milzlymphozyten nach Kultur mit a-GalCer Cytokine zu produzieren, ergab {\"a}hnlich wie in der Maus eine Produktion von IL-4 und IFN-g;. Aus diesem Grund kann eine fehlende Reaktivit{\"a}t von Ratten NKT Zellen f{\"u}r a-GalCer nicht der Grund f{\"u}r eine fehlende mCD1d Tetramerbindung sein. Um die Reaktivit{\"a}t der NKRP1A+TZR+ Rattenzellen auf a-GalCer besser zu verstehen, wurde der Ratten TZR analysiert. RT-PCR von Leberlymphozyten mit Va14-spezifischen Primern und die Analyse der klonierten PCR Produkte ergab ein viel schw{\"a}cheres Signal f{\"u}r Ratten als f{\"u}r Maus cDNA. Dar{\"u}ber hinaus zeigten Sequenzanalysen, daß das Va14 auch mit anderen J als dem f{\"u}r TCRinv typischem Ja18 rearrangiert war. Die niedrige Anzahl von Va14Ja18 „in frame" Umlagerungen legt Nahe, daß nur ein kleiner Anteil der Leber-lymphozyten CD1d restringierte NKT Zellen sind. Maus und humane NKT Zellen erkennen durch CD1d-b2m Komplexe pr{\"a}sentiertes a-GalCer und reagieren mit Aktivierung, Proliferation und Cytokinproduktion. Um die F{\"a}higkeit von Maus und Ratten-CD1d a-GalCer zu pr{\"a}sentieren, zu testen, wurde das CD1d Molek{\"u}l der Ratte kloniert. Sequenzanlyse und funktionelle Tests best{\"a}tigten die strukturelle und funktionelle Homologie des CD1d beider Spezies. Gleichzeitig wurde zur Analyse der Reaktivit{\"a}t von NKRP1A+TZR+ Zellen auf a-GalCer ein Ratten Va14+ invarianter TZR kloniert und in einem TZR- T-Zellhybridom (BWr/mCD28) exprimiert. Zellen die transgenen Ratten Va14+TZR und CD28 exprimierten, sezernierten IL-2 nach Stimulation mit aTZR/CD3 Antik{\"o}rper aber zeigten keine Spezifit{\"a}t f{\"u}r a-GalCer. Die fehlende Reaktivit{\"a}t f{\"u}r a-GalCer und die fehlende Bindung von mCD1-a-GalCer Tetramer waren wahrscheinlich durch Aminos{\"a}uresubstitionen insbesondere an Position 71 (51 nach IMGT Nomenklatur) der klonierten TZRa Kette begr{\"u}ndet. Eine „Umkehrung" dieser {\"A}nderung wurde mittels molekularbiologischer Techniken durchgef{\"u}hrt aber Expression dieses TZR auf BWr/mCD28 wurde nicht erreicht. Im Gegensatz zum invarianten Va14+ Ratten TZR war der Maus Va14+ TZR voll funktional und spezifisch f{\"u}r mCD1d Tetramer. KT12 Hybridom und Maus TZRinv exprimierende BWr/mCD28 Zellen wurden sowohl durch Ratten als durch Maus CD1d pr{\"a}sentiertes a-GalCer aktiviert. Dasselbe galt f{\"u}r TZR, die eine Maus Va14 TZR Kette und eine Ratten Vb8.4 TZR Kette enthielten. Im Gegensatz hierzu antworteten Linien mit mVa14 und Ratten Vb8.2 nur auf durch Ratten und nicht auf durch Maus CD1d pr{\"a}sentiertes a-GalCer und banden nahezu kein mCD1d Tetramer. Dies legt Nahe, daß Keimbahn kodierte der b-Kettenbereiche (CDR2 oder CDR4) speziesspezifische Bereiche des CD1d erkennen. Weiterhin wurde gefunden, das die Zytokinsekretion der Zellinien durch CD80 spezifische monoklonale Antik{\"o}rper inhibiert wurde, was eine wichtige Rolle der CD80-CD28 Interaktion bei der Aktivierung dieser Zellen nahelegt. Um zu sehen ob NKT Zellen auch in anderen Rattenst{\"a}mmen als F344 existieren, wurde H{\"a}ufigkeit und Funktion von NKRP1A+TZR+ Zellen in F344 und LEW Ratten miteinander verglichen. F344 und LEW, zwei Rattenst{\"a}mme die unterschiedliche CD1d Allele tragen, zeigten in der Analyse mit einem neu generierten rCD1d spezifischen monoklonalen Antik{\"o}rper nur geringe Unterschiede in der Expressionsst{\"a}rke. Hingegen, unterschieden sich beide St{\"a}mme in der Reaktivit{\"a}t f{\"u}r a-GalCer. NKRP1A+ Zellen waren in der LEW Ratte weniger h{\"a}ufig als in der F344 Ratte und antworteten in vitro nicht auf a-GalCer oder sein Analogon OCH. Ein Resultat, das insbesodere angesichts der besonderen Empf{\"a}nglichkeit von LEW Ratten f{\"u}r experimentell induzierte organspezifische Autoimmunerkrankungen von besonderem Interesse ist. Zusammgefasst kann gesagt werden, daß das Maus und Ratten CD1d/TZRinv NKT Zellsystem hohe strukturelle und funktionale Homologie aufweist, aber daß es wie im Menschen weniger invariante NKT Zellen in der Ratte als in der Maus gibt. TZR transgene Zelllinien wiesen ein speziesspezifisches Muster in der a-GalCer Erkennung auf, das f{\"u}r die Analyse von CDd/TZR-Kontaktbereichen von großem Nutzen sein wird. Dasselbe gilt f{\"u}r den Ratten und Maus-CD1d-spezifischen monoklonalen Antik{\"o}rper, der im Rahmen der Studie generiert wurde. Dieser kann bei der Charakterisierung der CD1d Proteinexpression in verschiedenen Geweben und der besseren funktionellen Charakterisierung von CD1d restringierten T Zellen der Ratte eingesetzt werden.},
  subject      = {Ratte},
  language  = {en}
}
@phdthesis{Ye2004,
  author    = {Ye, Fang},
  title     = {The role of DNA supercoiling in the coordinated regulation of gene expression in Helicobacter pylori},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9878},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Summary Mechanisms of global gene regulation in bacteria are not well characterized yet. Changes in global or local supercoiling of chromosomal DNA are thought to play a role in global gene silencing and gene activation. In Helicobacter pylori, a bacterium with few dedicated transcriptional regulators, the structure of some promoters indicates a dependency on DNA topology. For example, the promoter of the major flagellar subunit gene flaA ({\´o}28-dependent) has a shorter spacing of 13 nucleotides (nt) in comparison to the consensus promoter (15 nt). Supercoiling changes might be a mechanism of gene-specific and global transcriptional regulation in this bacterium. The aim of this study was to elucidate, if changes in global supercoiling have an influence on global gene regulation in H. pylori, and on the temporal regulation of the flagellar biosynthesis pathway in this organism. In the present work, global DNA supercoiling in H. pylori was visualized for the first time, by determining the supercoiling state of plasmids under different growth conditions. Using this method, we showed that cellular supercoiling was clearly growth phase-dependent in H. pylori. Coinciding with increased supercoiling during the growth phases, transcription of the flaA gene was increased, while the transcription of a second {\´o}28-dependent gene with regular promoter spacing (HP0472) was reduced, supporting the hypothesis that growth phase-dependency of promoters might be mediated by changes of DNA topology. Supercoiling in H. pylori could be influenced in a reproducible fashion by inhibition of gyrase using novobiocin, which led to DNA relaxation and to a concomitant decrease of flaA transcript levels. Promoter spacer mutagenesis of the flaA promoter was performed. With flaA promoters of increased or reduced length, transcription of flaA was reduced, less susceptible to supercoiling changes, and, under specific conditions, inverted as compared to the wild type promoter. Transcriptional interdependence between the coupled topA-flaB genes and flaA was found by analysis of the flaA promoter mutants. Chromosomally linked gyrA-flgR, and topA-flaB genes were all dependent on supercoiling and coregulated with each other. Comprehensive transcript profiling (DNA microarrays) of wildtype H. pylori with and without novobiocin treatment identified a number of genes (10\% of total genes), including flagellin, virulence and housekeeping genes, which were strongly dependent on and appeared to be synchronized by supercoiling changes (transcriptional up- or downregulation). These findings indicate a tightly coupled temporal regulation of flagellar biogenesis and metabolism in H. pylori, dependent on global supercoiling. A specific group of genes was also regulated in H. pylori by overexpression of Topoisomerase I, as detected by genome-wide analysis (DNA microarray). The DNA-bending protein HU is thought to be responsible for influencing the negative supercoiling of DNA, through its ability to wrap DNA. HU is encoded by the hup single gene in H. pylori, and constitutively expressed during the whole growth curve. An H. pylori hup mutant was constructed. H. pylori cells lacking HU protein were viable, but exhibited a severe growth defect. Our data indicate that the lack of HU dramatically changes global DNA supercoiling, indicating an important function of HU in chromosome structuring in H. pylori. Transcriptome analyses were performed and demonstrated that a total of 66 genes were differentially transcribed upon hup deletion, which include virulence genes and many other cell functions. The data indicate that HU might act as further important global regulator in H. pylori. Increased gene expression of heat shock proteins and a decreased transcription of the urease gene cluster may indicate a co-ordinated response of H. pylori to changes of environmental conditions in its specific ecological niche, mediated by HU. After the whole genomic sequences of H. pylori strains 26695 and J99 were published, two ORFs (HP0116 and HP0440) were presumptively annotated as topoisomerase I orthologs. HP0116 is the functional H. pylori topoisomerase I (TopA). HP0440 (topA2) was found in only few (5 of 43) strains. Western blot analysis indicated that TopA2 is antigenically different from TopA. TopA2 is transcribed in H. pylori, but the protein must be functionally different from TopA, since it is lacking one functionally essential zinc finger motif, and was not able to functionally complement a TopA-deficient E. coli. Like topA, topA2 was also transcribed in a growth phase-dependent manner. We did not find a function of TopA2 in DNA structuring or topology, but, in the present study, we were able for the first time to establish a unique function for TopA2 in global gene regulation, by comprehensive transcriptome analysis (DNA microarray). Transcriptome analysis showed that a total of 46 genes were differentially regulated upon topA2 deletion, which included flagellar genes and urease genes. These results suggest that TopA2 might act as a novel important regulator of both flagellar biosynthesis and urease in H. pylori.},
  subject      = {Helicobacter pylori},
  language  = {en}
}
@phdthesis{Jiang2004,
  author    = {Jiang, Fan},
  title     = {Water, mineral nutrient and hormone flows and exchanges in the hemiparasitic association between root hemiparasite Rhinanthus minor and the host Hordeum vulgare},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9863},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Summary Using the facultative root hemiparasite Rhinanthus minor and Hordeum vulgare as a host, several aspects of water relations, the flows and partitioning of mineral nutrients, the flows, depositions and metabolism of abscisic acid (ABA) and zeatin type cytokinins (zeatin Z, zeatin riboside ZR, zeatin nucleotide ZN) within the host, the parasite and between host and parasite and the flows and partitioning of the transport metabolites mannitol in the parasite, and of sucrose in the host, have been studied during the study period 41 to 54 days after planting, i.e about 30 to 43 days after successful attachment of the parasite to the host. Water relations Extraction of xylem sap by the parasite from the host's roots is facilitated by considerably higher transpiration per leaf area in the parasite than in the host and by the fact that stomata of attached Rhinanthus were wide open all day and night despite extremely high ABA concentrations in the leaves. By comparison, another related root hemiparasite, Melampyrum arvense, parasitising on various grasses in the field (botanic garden), showed normal diurnal stomatal behaviour. The abnormal behaviour of Rhinanthus stomata was not due to anatomical reasons as closure could be induced by applying high external ABA concentrations. Remarkable differences have been detected between the hydraulic conductance of barley seminal roots showing relatively low values, and that of Rhinanthus the seminal root showing very high values. The latter could be related to the observed high ABA concentrations in these roots. Whole plant water uptake, transpirational losses, growth-dependent deposition and the flows of water within the plants have been measured in singly growing Rhinanthus and Hordeum plants and in the parasitic association between the two. Water uptake, deposition and transpiration in Rhinanthus were dramatically increased after attachment to the barley host; most of the water used by the parasite was extracted as xylem sap from the host, thereby scavenging 20\% of the total water taken up by the host's roots. This water uptake by the parasitised host, however, due to a parasite induced reduction in the hosts growth, was decreased by 22\% as compared to non- parasitised barley. The overall changes in growth-related water deposition in host and parasite pointed to decreased shoot and relatively favoured root growth in the host and to strongly favoured shoot growth and less strongly increased root growth only in the parasite. These changes in the host became more severe, when more than one Rhinanthus was parasitising one barley plant. Mineral nutrients relations 5 mM NO3- supply In parasitising Rhinanthus shoot growth was 12-fold, but root growth only twofold increased compared to the non-parasitising (very small) plants. On the other hand, in the Hordeum host, shoot dry matter growth was clearly reduced, by 33\% in leaf laminae and by 52\% in leaf sheaths, whereas root growth was only slightly reduced as a consequence of parasitism. Growth-dependent increments of total N and P and of K, Ca and Mg in parasitising Rhinanthus shoot were strongly increased, particularly increments of total N and P, which were 18 and 42 times, respectively, higher than in the small solitary Rhinanthus. On the other hand, increments of the above mineral nutrients in leaf sheaths of parasitised Hordeum vulgare were more strongly decreased than in leaf laminae in response to parasitic attack. Estimation of the flows of nutrients revealed that Rhinanthus withdrew from the host xylem sap about the same percentage of each nutrients: 18\% of total N, 22\% of P and 20\% of K. Within the host almost all net flows of nutrient ions were decreased due to parasitism, but retranslocation from shoot to root-as related to xylem flow-was somewhat increased for all nutrients. Quantitative information is provided to show that the substantially increased growth in the shoot of attached Rhinanthus and the observed decrease in Hordeum shoot growth after infection were related to strongly elevated supply of nitrogen and phosphorus in the parasite and to incipient deficiency of these nutrients in the parasitised host. The flows of nutrients between host and parasite are discussed in terms of low selectivity of nutrient abstraction from the host xylem by the hemiparasite Rhinanthus minor. 1 mM NO3- or 1 mM NH4+ supply Rhinanthus shoot growth as measured by dry matter increase, was 19-fold (1 mM NO3-) and 15-fold (1 mM NH4+), but root growth only twofold (1 mM NO3-) and 2.9-fold (1 mM NH4+) increased-relative to singly growing Rhinanthus-when parasitising on host barley. In the Hordeum host, shoot dry matter growth was clearly reduced, whereas root growth was only slightly affected. Growth-dependent increments of total N and P and of K, Ca and Mg in parasitising Rhinanthus shoot were strongly increased, particularly increments of total N or of P, which were 20 or 53 times (1 mM NO3-) and 18 or 51 times (1 mM NH4+) , respectively, higher than those in solitary Rhinanthus. Within the host almost all net flows of nutrient ions were decreased due to parasitism. Flows of mannitol in parasite and sucrose flows in host barley When the plants were supplied with 5 mM NO3-, the biosynthesis of mannitol in Rhinanthus shoots increased 16-fold by parasitism, resulting in a 15-fold higher mannitol flow in the phloem and a 10-fold higher deposition in the shoot. Also the backward transport of mannitol in the xylem were increased 10-fold after attachment. Lower level nitrogen supply increased the deposition of mannitol in both single and attached Rhinanthus shoot and root. No mannitol was found in barley roots even in the direct vicinity of the haustoria. This indicates there are no backward transport of xylem sap from parasite to host. Compared to unparasitised barley, the net biosynthesis and deposition of sucrose in the shoot and the phloem flow was decreased substantially when plants were supplied with 5 mM NO3- or 1 mM NO3-. No sucrose has been detected in barley xylem sap and consequently there was no indication of a sucrose transfer from the host to the parasite. A possible involvement of mannitol in the abscisic acid relations of the parasite is discussed. ABA relations When the plants were supplied with 5 mM NO3-, there were weak or no effects of parasitism on ABA flows, biosynthesis and ABA degradation in barley. However, ABA growth-dependent deposition was significantly increased in the leaf laminae (3 fold) and in leaf sheath (2.4 fold), but not in roots. Dramatic changes in ABA flows, metabolism and deposition on a per plant basis, however, have been observed in Rhinanthus. Biosynthesis in the roots was 12-fold higher after attachment resulting in 14-fold higher ABA flows in the xylem. A large portion of this ABA was metabolised, a small portion was deposited. Phloem flows of ABA were increased 13-fold after attachment. The concentrations of ABA in tissues and xylem sap were higher in attached Rhinanthus by an order of magnitude than in host tissues and xylem sap. Similar dramatic difference existed when comparing the high concentrations in the xylem sap of single Rhinanthus with unparasitised barley. As compared to 5 mM NO3-, lower NO3- or 1 mM NH4+ supply doubled the ABA concentrations in barley leaf laminae, while having only small or no significant effects in the other organs. The possible special functions of ABA for the parasite are discussed. Zeatin type cytokinins relations Parasitism decreased, in the case of zeatin (Z), the synthesis (by 57\%) in the root, xylem flows (by 56\%) and metabolism (by 71\%) in leaf laminae, however, increased the phloem flows of zeatin massively (3-fold) in host barley. The deposition of zeatin in the root of Rhinanthus and the flowing in xylem and phloem were 24, 12, 29-fold, respectively, increased after successfully attaching to the host barley. However, net biosynthesis of zeatin in Rhinanthus roots decreased by 39\% after attachment. This indicates that a large portion (70\%) of xylem flow of zeatin in attached Rhinanthus was extracted from the host. In singly growing Rhinanthus plants, the balance of zeatin deposition in the shoot was negative, i.e. zeatin was metabolised and exported back to root in the phloem. The xylem flows of zeatin riboside (ZR) in barley decreased by 39\% after infected by Rhinanthus; phloem flow, which was 117\% relative to xylem flow was less decreased (by 13\%) after infection. Deposition of ZR has not been significantly affected in the leaf laminae, in leaf sheaths and roots. After parasitising on the host barley depositions in root, xylem flow and phloem flow increased 12, 18, 88-fold respectively in Rhinanthus. A large portion (57\%) of xylem flow of ZR in attached Rhinanthus was extracted from the host. In single Rhinanthus increament of shoot zeatin riboside was negative and a substantial portion was degraded in shoot and the rest was retranslocated back to the root in the phloem. A significant depositions of Z and ZR were detected in the haustoria of the Rhinanthus/barley association. Flows and deposition of zeatin nucleotides also have been investigated. The possible physiological functions of the large quantities of Z and ZR derived from the host barley, for the improved growth and the stomatal opening in the parasitising Rhinanthus are discussed.},
  subject      = {Hemiparasit},
  language  = {en}
}
@phdthesis{Pfeifer2004,
  author    = {Pfeifer, Thomas},
  title     = {Adaptive control of coherent soft X-rays},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9854},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The availability of coherent soft x-rays through the nonlinear optical process of high-harmonic generation allows for the monitoring of the fastest events ever observed in the laboratory. The attosecond pulses produced are the fundamental tool for the time-resolved study of electron motion in atoms, molecules, clusters, liquids and solids in the future. However, in order to exploit the full potential of this new tool it is necessary to control the coherent soft x-ray spectra and to enhance the efficiency of conversion from laser light to the soft x-ray region in the harmonic-generation process. This work developed a comprehensive approach towards the optimization of the harmonic generation process. As this process represents a fundamental example of \emph{light}--\emph{matter} interaction there are two ways of controlling it: Shaping the generating laser \emph{light} and designing ideal states of \emph{matter} for the conversion medium. Either of these approaches was closely examined. In addition, going far beyond simply enhancing the conversion process it could be shown that the qualitative spectral response of the process can be modified by shaping the driving laser pulse. This opens the door to a completely new field of research: Optimal quantum control in the attosecond soft x-ray region---the realm of electron dynamics. In the same way as it is possible to control molecular or lattice vibrational dynamics with adaptively shaped femtosecond laser pulses these days, it will now be feasible to perform real-time manipulation of tightly bound electron motion with adaptively shaped attosecond light fields. The last part of this work demonstrated the capability of the herein developed technique of coherent soft-x-ray spectral shaping, where a measured experimental feedback was used to perform a closed-loop optimization of the interaction of shaped soft x-ray light with a sulfur hexafluoride molecule to arrive at different control objectives. For the optimization of the high-harmonic-generation process by engineering the conversion medium, both the gas phase and the liquid phase were explored both in experiment and theory. Molecular media were demonstrated to behave more efficiently than commonly used atomic targets when elliptically polarized driving laser pulses are applied. Theory predicted enhancement of harmonic generation for linearly polarized driving fields when the internuclear distance is increased. Reasons for this are identified as the increased overlap of the returning electron wavefunction due to molecular geometry and the control over the delocalization of the initial electronic state leading to less quantum-mechanical spreading of the electron wavepacket during continuum propagation. A new experimental scheme has been worked out, using the method of molecular wavepacket generation as a tool to enhance the harmonic conversion efficiency in `pump--drive' schemes. The latter was then experimentally implemented in the study of high-harmonic generation from water microdroplets. A transition between the dominant laser--soft-x-ray conversion mechanisms could be observed, identifying plasma-breakdown as the fundamental limit of high-density high-harmonic generation. Harmonics up to the 27th order were observed for optimally laser-prepared water droplets. To control the high-harmonic generation process by the application of shaped laser light fields a laser-pulse shaper based on a deformable membrane mirror was built. Pulse-shape optimization resulted in increased high-harmonic generation efficiency --- but more importantly the qualitative shape of the spectral response could be significantly modified for high-harmonic generation in waveguides. By adaptive optimization employing closed-loop strategies it was possible to selectively generate narrow (single harmonics) and broad bands of harmonic emission. Tunability could be demonstrated both for single harmonic orders and larger regions of several harmonics. Whereas any previous experiment reported to date always produced a plateau of equally intense harmonics, it has been possible to demonstrate ``untypical'' harmonic soft x-ray spectra exhibiting ``switched-off'' harmonic orders. The high degree of controllability paves the way for quantum control experiments in the soft x-ray spectral region. It was also demonstrated that the degree of control over the soft x-ray shape depends on the high-harmonic generation geometry. Experiments performed in the gas jet could not change the relative emission strengths of neighboring harmonic orders. In the waveguide geometry, the relative harmonic yield of neighboring orders could be modified at high contrast ratios. A simulation based solely on the single atom response could not reproduce the experimentally observed contrast ratios, pointing to the importance of propagation (phase matching) effects as a reason for the high degree of controllability observed in capillaries, answering long-standing debates in the field. A prototype experiment was presented demonstrating the versatility of the developed soft x-ray shaping technique for quantum control in this hitherto unexplored wavelength region. Shaped high-harmonic spectra were again used in an adaptive feedback loop experiment to control the gas-phase photodissociation reaction of SF\$_6\$ molecules. A time-of-flight mass spectrometer was used for the detection of the ionic fragments. The branching ratios of particular fragmentation channels could be varied by optimally shaped soft x-ray light fields. Although in one case only slight changes of the branching ratio were possible, an optimal solution was found, proving the sufficient technical stability of this unique coherent soft-x-ray shaping method for future applications in optimal control. Active shaping of the spectral amplitude in coherent spectral regions of \$\sim\$10~eV bandwidth was shown to directly correspond to shaping the temporal features of the emerging soft x-ray pulses on sub-femtosecond time scales. This can be understood by the dualism of frequency and time with the Fourier transformation acting as translator. A quantum-mechanical simulation was used to clarify the magnitude of temporal control over the shape of the attosecond pulses produced in the high-harmonic-generation process. In conjunction with the experimental results, the first attosecond time-scale pulse shaper could thus be demonstrated in this work. The availability of femtosecond pulse shapers opened the field of adaptive femtosecond quantum control. The milestone idea of closed-loop feedback control to be implemented experimentally was expressed by Judson and Rabitz in their seminal work titled ``Teaching lasers to control molecules''. This present work extends and turns around this statement. Two fundamentally new achievements can now be added, which are ``Teaching molecules to control laser light conversion'' and ``Teaching lasers to control coherent soft x-ray light''. The original idea thus enabled the leap from femtosecond control of molecular dynamics into the new field of attosecond control of electron motion to be explored in the future. The \emph{closed}-loop approach could really \emph{open} the door towards fascinating new perspectives in science. Coming back to the introduction in order to close the loop, let us reconsider the analogy to the general chemical reaction. Photonic reaction control was presented by designing and engineering effective media (catalysts) and controlling the preparation of educt photons within the shaped laser pulses to selectively produce desired photonic target states in the soft x-ray spectral region. These newly synthesized target states in turn could be shown to be effective in the control of chemical reactions. The next step to be accomplished will be the control of sub-femtosecond time-scale electronic reactions with adaptively controlled coherent soft x-ray photon bunches. To that end a time-of-flight high-energy photoelectron spectrometer has recently been built, which will now allow to directly monitor electronic dynamics in atomic, molecular or solid state systems. Fundamentally new insights and applications of the nonlinear interaction of shaped attosecond soft x-ray pulses with matter can be expected from these experiments.},
  subject      = {Ultrakurzer Lichtimpuls},
  language  = {en}
}
@phdthesis{Baumeister2004,
  author    = {Baumeister, Joachim},
  title     = {Agile development of diagnostic knowledge systems},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9698},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The success of diagnostic knowledge systems has been proved over the last decades. Nowadays, intelligent systems are embedded in machines within various domains or are used in interaction with a user for solving problems. However, although such systems have been applied very successfully the development of a knowledge system is still a critical issue. Similarly to projects dealing with customized software at a highly innovative level a precise specification often cannot be given in advance. Moreover, necessary requirements of the knowledge system can be defined not until the project has been started or are changing during the development phase. Many success factors depend on the feedback given by users, which can be provided if preliminary demonstrations of the system can be delivered as soon as possible, e.g., for interactive systems validation the duration of the system dialog. This thesis motivates that classical, document-centered approaches cannot be applied in such a setting. We cope with this problem by introducing an agile process model for developing diagnostic knowledge systems, mainly inspired by the ideas of the eXtreme Programming methodology known in software engineering. The main aim of the presented work is to simplify the engineering process for domain specialists formalizing the knowledge themselves. The engineering process is supported at a primary level by the introduction of knowledge containers, that define an organized view of knowledge contained in the system. Consequently, we provide structured procedures as a recommendation for filling these containers. The actual knowledge is acquired and formalized right from start, and the integration to runnable knowledge systems is done continuously in order to allow for an early and concrete feedback. In contrast to related prototyping approaches the validity and maintainability of the collected knowledge is ensured by appropriate test methods and restructuring techniques, respectively. Additionally, we propose learning methods to support the knowledge acquisition process sufficiently. The practical significance of the process model strongly depends on the available tools supporting the application of the process model. We present the system family d3web and especially the system d3web.KnowME as a highly integrated development environment for diagnostic knowledge systems. The process model and its activities, respectively, are evaluated in two real life applications: in a medical and in an environmental project the benefits of the agile development are clearly demonstrated.},
  language  = {en}
}
@phdthesis{Rueter2004,
  author    = {R{\"u}ter, Katja},
  title     = {The efficiency of routine standards in social comparison},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9448},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {One primary source for self-knowledge is social comparison. Often objective criteria for self-evaluations are not available or useful and therefore comparisons with other people play a crucial role in self-evaluations. But the question is whether social comparisons could indeed provide information about the self without consuming too much cognitive resources or time. Therefore, in this research I wanted to look at practice effects in social comparison and the particular significance of routine standards. Whereas traditional research on standard selection mostly focused on goal-oriented and strategic standard selection processes, this research sets out to integrate social cognitive knowledge, ideas, and methods. Researchers from many different fields agree that people's behavior and thinking is not fully determined by rational choices or normative considerations. Quite the contrary, factors like knowledge accessibility, habits, procedural practice, stereotyping, categorization, and many more cognitive processes play an important role. The same may be true in social comparison and standard selection. In my research I demonstrate that efficiency concerns play an important role in social comparison. Since people may not be able to engage in a strategic standard selection whenever they engage in social comparison processes, there has to be a more efficient alternative. Using routine standards would be such an alternative. The efficiency advantage of routine standards may thereby be founded not only in the abandonment of a strategic but arduous standard selection process, but also in a higher efficiency of the comparison process itself. I therefore set out to show how the use of routine standards facilitates the social comparison processes. This was done in three steps. First, I replicated and improved our former research (Mussweiler \& R{\"u}ter, 2003, JPSP) indicating that people really do use their best friends as routine standards to evaluate themselves. Second, I demonstrated that it is more efficient to compare with a routine standard than with another standard. In Studies 2 and 3 I therefore show that comparisons between the self and a routine standard (either a natural routine standard like the best friend or a experimentally induced routine standard based on practice) are faster and more efficient than comparisons with other standards. Finally, I looked at the underlying mechanism of the efficiency advantage of routine standards. The results of Studies 4 and 5 point out, that both general as well as specific practice effects occur with repeated comparisons. Whereas a specific practice effect implies the repeated processing of the same content (i.e., knowledge about the routine standard), general practice effects indicate that the pure process (i.e., comparing the self with a routine standard) becomes more efficient regardless whether new content (i.e., comparison relevant knowledge) has to be processed. Taken together, the efficiency advantage of routine standards during self-evaluation is based not only on the lack of necessity for an arduous standard selection, but is additionally supported by the facilitation of the comparison process itself. The efficiency of routine standards may provide an explanation as to why people base self-evaluations on comparisons with these standards and dispense with strategic considerations to select the most suitable standard.},
  language  = {en}
}
@phdthesis{Kahlenberg2004,
  author    = {Kahlenberg, Frank},
  title     = {Structure-property correlations in fluoroaryl functionalized inorganic-organic hybrid polymers for telecom applications},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9378},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The development and in-depth characterization of new fluoroaryl functionalized ORMOCER® materials (inorganic-organic hybrid polymers) for optical waveguide applications in telecommunication is presented. The preparation of the materials included precursor silane synthesis, hydrolysis/polycondensation of organoalkoxysilane mixtures, and photolithographic processing of the resulting oligosiloxane resins in order to establish the inorganic-organic hybrid network. During all stages of ORMOCER® preparation, structure-property relations were deduced from characterization data, particularly with respect to low optical loss in the important near-infrared spectral region as well as refractive index. With the aid of molecular modeling, structural characteristics of oligomeric intermediates were visualized, which was found valuable in the fundamental understanding of the material class. The material development started with the syntheses of a variety of commercially unavailable fluorinated and unfluorinated arylalkoxysilanes by means of Grignard and hydrosilylation pathways, respectively. A survey of silane optical properties, particularly their absorptions at the telecom wavelengths 1310 nm and 1550 nm, gave an impulse to the choice of suitable precursors for the preparation of low-loss ORMOCER® resins. Accordingly, precursor silane mixtures and hydrolysis/polycondensation reaction conditions were chosen and optimized with regard to low contents of C-H and Si-OH functions. Thus, absorptions as low as 0.04 dB/cm at 1310 nm and 0.18 dB/cm at 1550 nm, respectively, could be obtained from an oligosiloxane resin based on pentafluorophenyltrimethoxysilane (1) mixed with pentafluorophenyl(vinyl)-dimethoxysilane (5). In order to improve the organic crosslinkability under photolithographic processing conditions, further resins on the basis of the aforementioned were prepared, which additionally incorporated the styrene-analogous precursor 4-vinyltetrafluorophenyl-trimethoxysilane (4). Thus, ORMOCER® resins with low optical losses of 0.28 dB/cm at 1310 nm and 0.42 dB/cm at 1550 nm, respectively, were prepared, which exhibited excellent photopatternability. The manufacture of micropatterns such as optical waveguide structures by UV-photolithography under clean room conditions was the final stage of material synthesis. The optimization of processing parameters allowed the preparation of test patterns for the determination of optical, dielectrical and mechanical properties. A low optical loss of 0.51 dB/cm at 1550 nm could be measured on a waveguide manufactured from a photopatternable fluoroaryl functionalized ORMOCER®. The structural characterization of liquid resins as well as cured ORMOCER® samples was accomplished chiefly with solution and solid state 29Si-NMR spectroscopy, respectively. Particularly for polycondensates incorporating species based on more than one precursor silane, the spectra showed a high degree of complexity. An additional challenge arouse from the partial loss of fluoroaryl groups during ORMOCER® condensation and curing, which resulted in even more condensation products. Thus, in order to provide a basis for resin analysis, first the hydrolysis/condensation reactions of the isolated precursors were investigated under reaction time-resolution with NMR spectroscopy at low temperature. Backed by signal assignments in these single-precursor systems, the respective species could also be identified in the complex resin spectra, allowing for their quantitative interpretation. The structural characterization was rounded out by IR spectroscopy and SAXS analyses. With the help of molecular modeling, the experimental data were finally transferred into a three-dimensional image of an organosiloxane oligomer, which is representative for a photopatternable fluoroaryl functionalized ORMOCER® resin. The combination of low-temperature NMR, which made the characterization of polycondensates possible, with oligomer modeling paved the way to a further understanding of ORMOCER® resin systems. On the basis of this visualization of structural characteristics, e.g. properties such as organic crosslinkability of oligomers were discussed in the light of steric features within the molecular structure. Thus, new possibilities were established for the systematic optimization of ORMOCER® formulations. Structure-property relations with respect to optical loss and refraction, as determined within this work, follow trends, which are in accordance with the literature. Particularly the direct comparison of data derived from analogous fluorinated and unfluorinated ORMOCER® resins showed that fluorination results in significant decrease in NIR optical loss. Additionally, different unfluorinated aryl functionalized systems with varying aliphatic C-H content were compared. In case of a lower aliphatic content, a widening effect on the 1310 nm window was found. This is due to a shift of arylic C-H vibrations (1145 nm) towards lower wavelengths compared to aliphatic C-H (1188 nm). Finally, on the basis of NIR spectra of analogous fluorinated resins with low and high silanol content, respectively, a significant impact of (Si)O-H groups on the 1550 nm window was demonstrated, while the 1310 nm window was unaffected. This is due to O-H vibrations with a maximum at 1387 nm and further bands at higher wavelength. The index of refraction was drastically lowered due to fluorination. Thus, the analogous fluorinated and unfluorinated ORMOCER® resins had indices of 1.497 and 1.570, respectively, in the VIS region. For the fluorinated systems, refraction did not change significantly during organic cross-connection and hardbake. In conclusion, the new fluoroaryl functionalized ORMOCER® systems represent low-loss materials for telecom applications. In addition, in-depth characterization during material development allowed the proposal of structure-property relations, particularly with respect to optical properties, which are of considerable importance for future developments.},
  subject      = {Ormocer},
  language  = {en}
}
@phdthesis{Tarcea2004,
  author    = {Tarcea, Nicolae},
  title     = {Light as a universal tool : Microcapsule sizing by elastic light scattering and mineral investigation by in situ Raman spectroscopy},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9383},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The present work consist of two major parts. The first part, extending over chapters 1, 2, 3 and 4, addresses the design and construction of a device capable of determining the shell thickness and the core size for monolayer spherical particles in a flow. The second part containing chapters 5, 6, 7, 8, 9 and 10, concentrate on the use of Raman spectroscopy as a space application, namely for use as a tool for in situ planetary investigations. This part directly addresses the MIRAS project, a study run under the auspices of Federal Ministry of Education and Research, BMBF and German Aerospace Center, DLR under national registration number 50OW0103. MIRAS stands for "Mineral Investigation by in situ Raman Spectroscopy". Microcapsule Sizing by Elastic Light Scattering The industrial development of processes based on microcapsules depends on the possibility to provide clear and complete information about the properties of these microcapsules. However, the tools for an easy and efficient determination of the microcapsule properties are lacking, several methods being often required to describe adequately the microcapsule behavior. Methods for evaluating the individual size and size distribution of both the core and the shell are required together with methods for measuring the mechanical strength, stability in appli-cation media, permeability of the shell, etc. Elastic light scattering measurements provide a possible way of determining properties such as core size, shell size and refractive index. The design and con-struction of a device capable of measuring the above mentioned parameters for a core-shell particle is the subject of the first part of this thesis. The basic principle of measurement for the device proposed here consists of an-alyzing one particle at a time by recording the elastic light scattering pattern at angles between approx. 60 and 120 grad. By comparing the experimentally recorded phase functions with the previously calculated phase functions stored in a database, the geometry of the scattering object can be identified. In our case the geometry is characterized by two parameters: the shell thickness and the core radius. In chapter 2 a short overview on the methods used for sizing microparticles is given. Different sizing methods are compared, and the advantages and disadvan-tages for the general problem of sizing are shortly discussed. It is observed that all sizing methods that are based on elastic light scattering theories are ensemble methods. Chapter 3 focusses on the theories used for calculating the theoretical scattering patterns with emphasize on the Mie theory. The generalization of Mie theory for layered particles is shortly presented and the far field intensity approximations are discussed. The last chapter (4) of this first part describes the experimental approach for building an automatic microcapsule sizer. The approach started by O. Sbanski [76] with the development of a software packet for calculating and storing theoret-ical phase functions for core-shell particles was continued with the designing and construction of a measuring device. The hardware construction and the software with all implemented corrections imposed by the individual setup components are described in detail. For the laser, the monochromaticity, the intensity profile of the beam as well as the planarity of the equi-phase fronts are taken into consid-eration. The flow cell with three different designs is described, and the influences of the employed design on the light scattering patterns are discussed together with the optical system used for recording the experimental phase functions. The detection system formed by two identical linear CCD arrays is presented together with the software approach used for data acquisition. Ways of improving the quality and the speed of the analyzing process are discussed. The final section presents measurements run on samples made of homogeneous spheres and also on samples containing industrial microcapsules. Mineral Investigation by in situ Raman Spectroscopy The envisaged future planetary missions require space-born instruments, which are highly miniaturized with respect to volume and mass and which have low needs of power. A micro Raman spectrometer as a stand alone device on a planetary surface (e.g. Mars) offers a wide spectrum of possibilities. It can assess the chemical analysis via determination of the mineral composition, detect organic molecules in the soil, identify the principal mineral phases, etc. The technical developments in the last years have introduced a new generation of small Raman systems suitable for robotic mineral characterization on planetary surfaces [20, 95]. Two different types of spectrometer were considered for the MIRAS study. As supporting laboratory experiments for the MIRAS study, the measure-ments on standard minerals and on SNC Mars meteorites are discussed in chapter 6. The following SNC meteorites have been investigated: Sayh al Uhaymir 060, Dar al Gani 735, Dar al Gani 476, Northwest Africa 856, Los Angeles, Northwest Africa 1068 and Zagami. Pyrite as a hitherto undescribed phase in the picritic (olivin-phyric) shergottite NWA 1068 as well as reduced carbon (e.g. graphite) and anatase in the shergottite Say al Uhaymir 060 are new findings for this class of meteorites. A detailed description of the proposed designs for MIRAS, with the compo-nents used for building the test version on a breadboard is covered in chapter 7. The scientific as well as the mission requirements imposed on the instrument are discussed. The basic design is presented and the main components that are brought together to build the device being the laser unit, the Raman head, the Rayleigh filtering box, and the spectral sensor (spectrometer with a matching de-tector) are described. The two proposed designs, one based on an acousto-optic tunable filter (AOTF) and the other based on a dispersive hadamard transform spectrometer are compared to each other. The actual breadboard setup with the detailed description of the components follows in Section 7.3. Further de-velopment of a Raman spectrometer for planetary investigations is proposed in combination with a microscope as part of the Extended-MIRAS project. The software developed for controlling the breadboard version of MIRAS is described in chapter 8 together with a short description of the structure of a relational database used for in house spectra management. The measuring pro-cedures and the data processing steps are presented. Spectra acquired with the MIRAS breadboard version based on the AOTF are shown in chapter 9. The final chapter addresses a rather different possibility of using Raman spectroscopy for planetary investigations. The chapter summarizes the content of four tech-nical notes that were established within the study contracted by the European Space Agency with firma Kayser-Threde in Munich concerning the possibility of applying Raman spectroscopy in the field of remote imaging.},
  language  = {en}
}
@phdthesis{Geiger2004,
  author    = {Geiger, Lars},
  title     = {The versatile use of Guanidiniocarbonylpyrroles : from self-assembly to peptide recognition},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9272},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Die vorliegende Arbeit gliedert sich in zwei Themenschwerpunkte. Ein supramolekulares Projekt beinhaltete die Entwicklung von neuen flexiblen, selbst-aggregierenden Zwitterionen als Bausteine f{\"u}r supramolekulare Polymere. In einem zweiten bioorganischem Teil bestand das Ziel darin, Rezeptoren f{\"u}r Aminos{\"a}uren und Dipeptide in Wasser zu entwickeln. Beide Projekte basieren auf dem Guanidiniocarbonylpyrrol als effizientes Bindungsmotiv f{\"u}r die Komplexierung von Carboxylaten in w{\"a}ssrigen L{\"o}sungen. Eine notwendige Voraussetzung f{\"u}r die Realisierung dieser Projekte war jedoch zun{\"a}chst die Entwicklung einer allgemeinen, effizienten und milden Synthese f{\"u}r Guanidiniocarbonylpyrrole. Die bei der zuvor verwendeten Methode aggressiven Reaktionsbedingungen und die problematische Aufreinigung verhinderten eine gr{\"o}ßere Anwendung dieses Bindungsmotivs in bioorganischen und supramolekularen Projekten. Im Rahmen dieser Arbeit gelang es mir erfolgreich eine neue Syntheseroute zu entwickeln. Hierbei wurde mono-tBoc-Guanidine mit dem Benzylester mittels PyBOP gekuppelt und nach Entsch{\"u}tzung der Benzylschutzgruppe wurde die zentrale Zwischenstufe f{\"u}r die weiteren Synthesen, die tBoc-gesch{\"u}tzte Guanidinocarbonylpyrrol-S{\"a}ure erhalten. Durch diese neuartige Synthese war es m{\"o}glich, eine Reihe von flexiblen Zwitterionen 3-6 herzustellen und deren Selbst-Aggregation und den Einfluß der Kettenl{\"a}nge und somit Flexibilit{\"a}t der Alkylkette auf Struktur und Stabilit{\"a}t der gebildeten Aggregate in L{\"o}sung sowie auch in der Gasphase zu untersuchen. In DMSO deuten NMR-Verd{\"u}nnungsreihen darauf hin, dass die flexiblen Zwitterionen mit n = 1, 3 und 5 oligomere Strukturen ausbilden. Im Falle von n = 1 werden hoch stabile helicale und Nanometer große Aggregate in der gebildet. In den Gasphasen-Studien wurde die Stabilit{\"a}t und Zerfallskinetik einer Reihe von Natriumaddukten der Dimere von n = 2, 3 und 5 untersucht. Dieses gelang durch die Methode der „infrared multiphoton dissociation Fourier transform ion cyclotron resonance mass spectrometry" (IRMPD-FT-ICR MS). Solche Studien erm{\"o}glichen m{\"o}glicherweise in Zukunft das gezielte Design von supramolekularen Bausteinen. Der bioorganische Teil meiner Arbeit setzte sich aus drei Einzelprojekten zusammen. So synthetisierte ich durch eine f{\"u}nfstufige Synthesesequenz vier neue Arginin-Analoga, die in Zukunft als Ersatz f{\"u}r Arginin in Peptide eingebaut werden k{\"o}nnen. Als Testreaktion f{\"u}r die Eignung dieser Verbindungen in einer Festphasenpeptidsynthese, wurde ein Tripetid Ala-AA1-Val (AA: Arginin-Analogon) mit einem eingebauten Arginin-Analogon erfolgreich hergestellt. In einem zweiten Projekt habe ich den Einfluß einer zus{\"a}tzlichen ionischen Wechselwirkung in unserem Bindungsmotiv untersucht. Dazu wurde ein zweifach-kationischer Rezeptor und der dreifach-geladenen Rezeptor synthetisiert und physikalisch-organisch ihre Bindungseigenschaften mit Hilfe von NMR-Titrationsexperimenten gegen eine Reihe von Aminos{\"a}uren untersucht. Der dreifach-kationische Rezeptor 11 zeigte hierbei herausragende Bindungseigenschaften und war um ca. den Faktor 100 besser als f{\"u}r die bisher bekannten Guanidiniocarbonylpyrrole. Die Assoziationskonstanten waren auch fast reinem Wasser mit bis zu Kass = 2000 noch bemerkenswert hoch. Im dritten Projekt habe ich einen de-novo entwickelten Rezeptor f{\"u}r C-terminale Dipeptide in einer beta-Faltblatt Struktur entwickelt.Dieser Rezeptor wurde mittels NMR and UV-Titrationen untersucht. In 40 \% Wasser/ 60 \% DMSO waren die Bindungskonstanten zu hoch um {\"u}berhaupt quantifiziert zu werden. Deshalb wurden die Bindungseigenschaften des Rezeptors mittels UV Titrationen in einer Mischung aus 90 \% Wasser mit 10 \% DMSO gegen eine Reihe von Dipeptiden und Aminos{\"a}uren getestet. Die Bindungsdaten zeigen, dass Rezeptor Dipeptide mit ausgezeichneten Bindungskonstanten (Kass > 10000 M-1) komplexiert. Im Gegensatz dazu bindet der Rezeptor 12 Aminos{\"a}uren um den Faktor zehn schlechter (Kass > 1000 M-1). Die Komplexstabilit{\"a}t nimmt hierbei in Abh{\"a}ngigkeit von der Seitenkette des Dipeptids in der Reihe Gly < Ala < Val zu, was sich mit der abnehmenden Flexibilit{\"a}t und zunehmenden Hydrophobizit{\"a}t der Seitenkette erkl{\"a}ren l{\"a}sst. Diese Eigenschaften machen den Rezeptor 12 zu dem besten bisher bekannten Dipeptidrezeptor in w{\"a}ssrigen L{\"o}sungen. Innerhalb meiner Arbeit gelang es mir somit, nicht nur eine essentiell wichtige, milde und effiziente Synthese f{\"u}r Guanidinocarbonylpyrrole zu entwickeln, sondern es gelang mir ebenso ein neues Bindungsmotiv f{\"u}r die Komplexierung von Aminos{\"a}uren in Wasser zu entwickeln. Zus{\"a}tzlich konnte noch der Dipeptidrezeptor erfolgreich synthetisiert und untersucht werden. Mit Bindungskonstanten f{\"u}r von Kass > 10000 M-1 ist er der derzeit beste Dipeptidrezeptor in w{\"a}ssriger L{\"o}sung.},
  subject      = {Guanidinderivate},
  language  = {en}
}
@phdthesis{Planchet2004,
  author    = {Planchet, Elisabeth},
  title     = {Nitric oxide production by tobacco plants and cell cultures under normal conditions and under stress},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9339},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Stickstoffmonoxid (NO) ist ein gasf{\"o}rmiges freies Radikal. In tierischen Geweben ist NO an der Regulation vieler physiologischer Prozesse beteiligt. In den letzten zehn Jahren wurde immer wahrscheinlicher, dass NO auch in Pflanzen als „second messenger" fungiert. Besonderes Interesse fanden Berichte, dass NO als intermedi{\"a}res Signal bei der Induktion der hypersensitiven Antwort (HR) von Pflanzen auf Pathogene involviert ist. Im Gegensatz zu Tieren haben Pflanzen wahrscheinlich eine Reihe verschiedener Systeme, die NO produzieren k{\"o}nnen. Potentielle Kandidaten daf{\"u}r sind: cytosolische Nitratreduktase (NR; EC 1.6.6.1), PM-gebundene Nitrit: NO Reduktase (Ni:NOR), NO-Synthase (NOS; EC 1.14.13.39) und Xanthindehydrogenase (XDH; EC 1.1.1.204). Das Ziel dieser Arbeit bestand darin, die NO-Produktion von Pflanzen zu quantifizieren und die beteiligten enzymatischen Schritte zu identifizieren. Als wichtigste Methode zur NO-Messung wurde die Chemilumineszenz verwendet, mit der die NO Emission aus Pflanzen, Zellsuspensionen oder Enzyml{\"o}sungen in NO-freie Luft oder N2 in Echtzeit verfolgt werden konnte. Wir benutzten f{\"u}r unsere Analyse: Tabak Wildtyp (N. tabacum cv Xanthi oder cv Gatersleben) und Zellsuspensionskulturen davon, NR-freie Mutanten oder WT Pflanzen, die auf Ammonium angezogen wurden um NR-Induktion zu vermeiden, Pflanzen die auf Wolframat an Stelle von Molybdat wuchsen um die Synthese funktionierender MoCo-Enzyme zu unterdr{\"u}cken, und eine NO-{\"u}berproduzierende, Nitritreduktase (NiR)-defiziente Transformante. Normale Bl{\"a}tter von nitratern{\"a}hrten Pflanzen zeigten eine typisches NO-Emissionsmuster,bei dem die NO-Emission im Dunkeln niedrig, im Licht viel h{\"o}her, und unter anoxischen Bedingungen im Dunkeln mit weitem Abstand am h{\"o}chsten war. Aber selbst nach Erreichen maximaler Raten war die NO-Emission h{\"o}chstens 1 \% der extrahierbaren NR Aktivit{\"a}t. Auch eine L{\"o}sung hochgereinigter Nitratreduktase produzierte NO aus den Substraten Nitrit und NADH, und auch hier war die Rate der NO-Emission nur maximal 1\% der vorhandenen NR-Aktivit{\"a}t. Dieses {\"u}bereinstimmende Verh{\"a}ltnis von NR Aktivit{\"a}t und NO-Emission in Bl{\"a}ttern, Zellsuspensionen und einer NR-L{\"o}sung zeigt an dass die NO-L{\"o}schung nur gering war und dass deshalb die NO-Emissionsmessung eine zuverl{\"a}ssige Methode zur Quantifizierung der NO Produktion sein sollte. Die NO-Emission aus einer NiR-defizienten, nitritakkumulierenden Transformante warimmer sehr hoch. NR-freie Pflanzen oder Zellsuspensionen produzierten dagegen normalerweise kein NO, woraus geschlossen werden konnte, dass hier NR die einzige NOQuelle war. Die Rate war in der Regel korreliert mit der Nitritkonzentration, aber cytosolisches NADH erschien als ein weiterer wichtiger limitierender Faktor.{\"U}berraschenderweise reduzierten aber auch NR-freie Pflanzen oder Zellkulturen unter anoxischen Bedingungen Nitrit zu NO. Das beteiligte Enzymsystem war kein MoCo-Enzym und war Cyanid-sensitiv. Der pilzliche Elicitor Cryptogein induzierte nach Infiltration in Bl{\"a}tter oder nach Zugabe zu Zellsuspensionen bereits in nanomolaren Konzentrationen den Zelltod. Diese Antwort wurde verhindert oder zumindest stark verz{\"o}gert durch den NO-Scavenger PTIO oder c-PTIO. Die Schlussfolgerung war zun{\"a}chst, das NO tats{\"a}chlich an der HR-Induktion involviert war. Da aber das Reaktionsprodukt von c-PTIO und NO, c-PTI, den HR ebenfalls verhinderte ohne jedoch NO zu l{\"o}schen, scheint die weit verbreitete Verwendung von c-PTIO und seinen Derivaten f{\"u}r die Beweisf{\"u}hrung einer Beteiligung von NO zumindest fragw{\"u}rdig. Der HR wurde unterschiedslos sowohl in WT-Pflanzen als auch in NR-freien Pflanzen bzw. Zellsuspensionen induziert. NR ist also offensichtlich f{\"u}r den HR nicht erforderlich. Im Gegensatz zur publizierten Literaturdaten verhinderte auch eine kontinuierliche hohe {\"U}berproduktion von NO die Auspr{\"a}gung des HR nicht. Besonders {\"u}berraschend war der Befund, dass trotz der Hemmung des HR durch PTIO keinerlei Cryptogein-induzierte NO Produktion in Bl{\"a}ttern messbar war. Allerdings wurde in nitratern{\"a}hrten Zellsuspensionskulturen ca. 3-6 h nach Cryptogein-Gabe eine -wenn auch geringe-NOEmission beobachtet, die von einer Nitritakkumulation begleitet war. Beides blieb in Ammonium-ern{\"a}hrten Kulturen aus. Hier schien also eine gewisse Relation zwischen Cryptogein-induzierter NO Emission, NR und Nitrit zu bestehen, die im Detail noch nicht verstanden ist. Da der Zelltod aber auch in NR-freien Zellsuspensionskulturen auftrat, besteht offensichtlich kein kausaler Zusammenhang zwischen dieser NO-Emission, Nitritakkumulation und der Cryptogein-Wirkung. Da NOS-Inhibitoren weder den Zelltod noch die nitritanh{\"a}ngige NO-Emission verhinderten, scheint eine NOS-artige Aktivit{\"a}t ebenfalls keine Rolle zu spielen. Insgesamt werden damit die in der Literatur etablierte Rolle von NO als Signal beim HR und die Rolle von NOS als NO-Quelle stark in Frage gestellt.},
  subject      = {Tabak},
  language  = {en}
}
@phdthesis{Petrovic2004,
  author    = {Petrovic, Suzana},
  title     = {In vivo analysis of homing pattern and differentiation potential of cells deriving from embryonic and adult haematopoietic regions},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9323},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {The experimental work of this thesis addresses the questions of whether established cell lines injected into murine blastocysts find their way back home and seed preferentially at the site of their origin. Furthermore, can they change their fate and differentiate to unrelated cell types when exposed to the embryonic environment. This survey was based on the fact that different cell lines have different potentials in developing embryos, dependent on their cellular identity. The cell lines used in this survey were AGM region-deriving DAS 104-4, DAS 104-8 cells, yolk sac-deriving YSE cells and bone marrow-deriving FDCP mix cells. These cells were injected into mouse blastocysts. Donor cells were traced in developing embryos via specific markers. Analysis of the embryos revealed that DAS cells are promiscuous in their seeding pattern, since they were found in all analysed tissues with similar frequencies. YSE cells showed preferences in seeding yolk sac and liver. YSE donor cells in chimaeric tissues were not able to change their immuno-phenotype, indicating that they did not change their destiny. Analysis of adult mice did not reveal any of YSE-derived cells donor contribution. In contrast, FDCP mix cells mostly engrafted haematopoietic tissues, although the embryos analysed by in situ hybridization had donor signals frequently in cartilage primordia, heads, and livers. Analysis of whether FDCPmix-derived cells found in foetal livers were of haematopoietic or hepatocytes nature showed that progeny of injected FDCP mix cells do not differentiate into cells that express a hepatocyte-specific marker. Further analysis showed that FDCPmix-derived donor cells found in brain express neural or haematopoietic markers. In order to reveal if they transdifferentiate to neurons or fuse with neurons/glial cells, nuclear diameters of donor and recipient cells were determined. Comparison of the nuclear diameters of recipient and donor cells revealed no differences. Therefore this suggests that progeny of FDCP mix in brain are not fusion products. Analysis of adult mice tissues revealed that presence of FDCP mix-derived cells was the highest in brains. These results confirmed the assumption that the developmental potential of the analysed cells cannot be easily modified, even when exposed to early embryonic environment. Therefore one can conclude that the analysed cell types had different homing patterns depending on their origins.},
  subject      = {Zelllinie},
  language  = {en}
}
@phdthesis{Rouziere2004,
  author    = {Rouzi{\`e}re, Anne-Sophie},
  title     = {MODULATION OF THE B-CELL REPERTOIRE IN RHEUMATOID ARTHRITIS BY TRANSIENT B-CELL DEPLETION},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9290},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Although the role of B-cells in autoimmunity is not completely understood, their importance in the pathogenesis of autoimmune diseases has been more appreciated in the past few years. It is now well known that they have roles in addition to (auto) antibody production and are involved by different mechanisms in the regulation of T-cell mediated autoimmune disorders. The evolution of an autoimmune disease is a dynamic process, which takes a course of years during which complex immunoregulatory mechanisms shape the immune repertoire until the development of clinical disease. During this course, the B-cell repertoire itself is influenced and a change in the distribution of immunoglobulin heavy and light chain genes can be observed. B-cell depletive therapies have beneficial effects in patients suffering from rheumatoid arthritis (RA), highlighting also the central role of B-cells in the pathogenesis of this disease. Nevertheless, the mechanism of action is unclear. It has been hypothesised that B-cell depletion is able to reset deviated humoral immunity. Therefore we wanted to investigate if transient B-cell depletion results in changes of the peripheral B-cell receptor repertoire. To address this issue, expressed immunoglobulin genes of two patients suffering from RA were analysed; one patient for the heavy chain repertoire (patient H), one patient for the light chain repertoire (patient L). Both patients were treated with rituximab, an anti-CD20 monoclonal antibody that selectively depletes peripheral CD20+ B-cells for several months. The B-cell repertoire was studied before therapy and at the earliest time point after B-cell regeneration in both patients. A longer follow-up (up to 27 months) was performed in patient H who was treated a second time with rituximab after 17 months. Heavy chain gene analysis was carried out by nested-PCR on bulk DNA from peripheral B-cells using family-specific primers, followed by subcloning and sequencing. During the study, patient H received two courses of antibody treatment. B-cell depletion lasted 7 and 10 months, respectively and each time was accompanied by a clinical improvement. Anti-CD20 therapy induced two types of changes in this patient. During the early phase of B-cell regeneration, we noticed the presence of an expanded and recirculating population of highly mutated B-cells. These cells expressed very different immunoglobulin VH genes compared before therapy. They were class-switched and could be detected for a short period only. The long-term changes were more subtle. Nevertheless, characteristic changes in the VH2 family, as well as in specific mini-genes like VH3-23, 4-34 or 1-69 were noticed. Some of these genes have already been reported to be biased in autoimmune diseases. Also in autoimmune diseases, in particular in RA, clonal B-cells have been frequently found in the repertoire. B-cell depletion with anti-CD20 antibody resulted in a long term loss of clonal B-cells in patient H. Thus, temporary B-cell depletion induced significant changes in the heavy chain repertoire. For the light chain gene analysis, the repertoire changes were analysed separately for naive (CD27-) and memory (CD27+) B-cells. Individual CD19+ B-cells were sorted into CD27- and CD27+ cells and single cell RT-PCR was performed, followed by direct sequencing. During the study, patient L received one course of antibody treatment. B-cell depletion lasted 10 months and the light chain repertoire was studied before and after therapy. Before therapy, some differences in the distribution of VL and JL genes were observed between naive and memory B-cells. In particular, the predominant usage of Jk-proximal Vk genes by the CD27- naive B-cells indicated that the receptor editing was less frequent in this population compared to memory cells. In VlJl rearrangements also, some evidence for decreased receptor editing was noticed, with the overrepresentation of the Jl2/3 gene segments. The CDR3 regions of naive and memory cells showed different characteristics: the activity of the terminal deoxynucleotidyl transferase and exonuclease in Vl(5') side was greater in memory cells. Also in the light chain repertoire, we observed some changes induced by the B-cell depletive therapy. There was a tendency of a less frequent usage of Jk-proximal Vk genes in the naive population. Some Vl genes, previously described in autoimmune diseases and connected to rheumatoid factor activity, such as 3p, 3r, 1g, were not found after therapy. The different characteristics of the CDR3 regions of VlJl rearrangements were not observed anymore. Very significantly, the ratio Vk to Vl was shifted toward a greater usage of Vk genes in the naive population after therapy. Taken together, these results indicate that therapeutic transient B-cell depletion by anti-CD20 antibody therapy modulates the immunoglobulin gene repertoire in the two RA patients studied. Measurable changes were observed in the heavy chain as well as in the light chain repertoire, which may be relevant to the course of the disease. This also supports the notion that the composition of the B-cell repertoire is influenced by the disease and that B-cell depletion can reset biases that are typically found in autoimmune diseases.},
  subject      = {Rheumatoide Arthritis},
  language  = {en}
}
@phdthesis{Grozdanov2004,
  author    = {Grozdanov, Lubomir Assenov},
  title     = {Analysis of the genome organization and fitness traits of non-pathogenic Escherichia coli strain Nissle 1917 (O6:K5:H1)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9304},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {In the last years more than one hundred microbial genomes have been sequenced, many of them from pathogenic bacteria. The availability of this huge amount of sequence data enormously increases our knowledge on the genome structure and plasticity, as well as on the microbial diversity and evolution. In parallel, these data are the basis for the scientific "revolution" in the field of industrial and environmental biotechnology and medical microbiology - diagnostics and therapy, development of new drugs and vaccines against infectious agents. Together with the genomic approach, other molecular biological methods such as PCR, DNA-chip technology, subtractive hybridization, transcriptomics and proteomics are of increasing importance for research on infectious diseases and public health. The aim of this work was to characterize the genome structure and -content of the probiotic Escherichia coli strain Nissle 1917 (O6:K5:H31) and to compare these data with publicly available data on the genomes of different pathogenic and non-pathogenic E. coli strains and other closely related species. A cosmid genomic library of strain Nissle 1917 was screened for clones containing the genetic determinants contributing to the successful survival in and colonization of the human body, as well as to mediate this strain's probiotic effect as part of the intestinal microflora. Four genomic islands (GEI I-IVNissle 1917) were identifed and characterized. They contain many known fitness determinants (mch/mcm, foc, iuc, kps, ybt), as well as novel genes of unknown function, mobile genetic elements or newly identified putative fitness-contributing factors (Sat, Iha, ShiA-homologue, Ag43-homologues). All islands were found to be integrated next to tRNA genes (serX, pheV, argW and asnT, respectively). Their structure and chromosomal localization closely resembles those of analogous islands in the genome of uropathogenic E. coli strain CFT073 (O6:K2(?):H1), but they lack important virulence genes of uropathogenic E. coli (hly, cnf, prf/pap). Evidence for instability of GEI IINissle 1917 was given, since a deletion event in which IS2 elements play a role was detected. This event results in loss of a 30 kb DNA region, containing important fitness determinants (iuc, sat, iha), and therefore probably might influence the colonization capacity of Nissle 1917 strain. In addition, a screening of the sequence context of tRNA-encoding genes in the genome of Nissle 1917 was performed to identify genome wide potential integration sites of "foreign" DNA. As a result, similar "tRNA screening patterns" have been observed for strain Nissle 1917 and for the uropathogenic E. coli O6 strains (UPEC) 536 and CFT073. I. Summary 4 The molecular reason for the semi-rough phenotype and serum sensitivity of strain Nissle 1917 was analyzed. The O6-antigen polymerase-encoding gene wzy was identified, and it was shown that the reason for the semi-rough phenotype is a frame shift mutation in wzy, due to the presence of a premature stop codon. It was shown that the restoration of the O side-chain LPS polymerization by complementation with a functional wzy gene increased serumresistance of strain Nissle 1917. The results of this study show that despite the genome similarity of the E. coli strain Nissle 1917 with the UPEC strain CFT073, the strain Nissle 1917 exhibits a specific set of geno- and phenotypic features which contribute to its probiotic action. By comparison with the available data on the genomics of different species of Enterobacteriaceae, this study contributes to our understanding of the important processes such as horizontal gene transfer, deletions and rearrangements which contribute to genome diversity and -plasticity, and which are driving forces for the evolution of bacterial variants. At last, the fim, bcs and rfaH determinats whose expression contributes to the mutlicellular behaviour and biofilm formation of E. coli strain Nissle 1917 have been characterized.},
  subject      = {Escherichia coli},
  language  = {en}
}
@phdthesis{Henn2004,
  author    = {Henn, Julian},
  title     = {The electron density : a bridge between exact quantum mechanics and fuzzy chemical concepts},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9003},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Summary The nature of the chemical bond is a topic under constant debate. What is known about individual molecular properties and functional groups is often taught and rationalized by explaining Lewis structures, which, in turn, make extensive use of the valence concept. The valence concept distinguishes between electrons, which do not participate in chemical interactions (core electrons) and those, which do (single, double, triple bonds, lone-pair electrons, etc.). Additionally, individual electrons are assigned to atomic centers. The valence concept is of paramount success: It allows the successful planning of chemical syntheses and analyses, it explains the behavior of individual functional groups, and, moreover, it provides the "language" to think of and talk about molecular structure and chemical interactions. The resounding success of the valence concept may be misleading to forget its approximative character. On the other hand, quantum mechanics provide in principle a quantitative description of all chemical phenomena, but there is no discrimination between electrons in quantum mechanics. From the quantum mechanical point of view there are only indistinguishable electrons in the field of the nuclei, i.e., it is impossible to assign a given electron to a particular center or to ascribe a particular purpose to individual electrons. The concept of indistinguishability of micro particles is founded on the Heisenberg uncertainty relation, which states, that wavepackets diverge in the 6N dimensional phase space, such that individual trajectories can not be identified. Hence it is a deep-rooted and approved physical concept. As an introduction to the present work density partitioning schemes were discussed, which divide the total molecular density into chemically meaningful areas. These partitioning schemes are intimately related to either the concepts of bound atoms in a molecule (as in the Atoms In Molecules theory (AIM) according to Bader or as in the Hirshfeld partitioning scheme) or to the concept of chemical structure in the sense of Lewis structures, which divide the total molecular density into core and valence density, where the valence density is split up again into bonding and non-bonding electron densities. Examples are early and recent loge theories, the topological analysis by means of the Electron Localization Function (ELF), and the Natural Bond Orbital (NBO) approach. Of these partitioning schemes, the theories according to Bader (AIM), to Becke and Edgecomb (ELF) and according to Weinhold (NBO and Natural Resonance Theory, NRT), respectively, were reviewed in detail critically. Points of criticism were explicated for each of the mentioned theories. Since theoretically derived electron densities are to be compared to experimentally derived densities, a brief introduction into the theory of X-ray di®raction experiments was given and the multipole formalism was introduced. The procedure of density refinement was briefly discussed. Various suggestions for improvements were developed: One strategy would be the employment of model parameters, which are to a maximum degree mutually orthogonal, with the object of minimizing correlations among the model parameters, e.g., to introduce nodal planes into the radial functions of the multipole model. A further suggestion involves the guidance of the iterative refinement procedure by an extremum principle, which states, that when di®erent solutions to the least squares minimization problem are available with about the same statistical measures of quality and with about the same residual density, then the solution is to prefer, which yields a minimum density at the bond critical point (BCP) and a maximum polarity in terms of the ratio of distances between the BCP and the nuclei. This suggestion is based on the well known fact, that the bond polarity (in terms of the ratio of distances between the BCP and the respective nuclei) is underestimated in the experiment. Another suggestion for including physical constraints is the explicit consideration of the virial theorem, e.g., by evaluating the integration of the Laplacian over the entire atomic basins and comparing this value to zero and to the value obtained from the integration of the electron gradient field over the atomic surface. The next suggestion was to explicitly use the electrostatic theorem of Feynman (often also denoted as Hellmann-Feynman theorem), which states, that the forces onto the nuclei can be calculated from the purely classical electrostatic forces of the electron distribution and the nuclei distribution. For a stationary system, these forces must add to zero. This also provides an internal quality criterion of the density model. This can be performed in an iterative way during the refinement procedure or as a test of the final result. The use of the electrostatic theorem is expected to reduce significantly correlations among static density parameters and parameters describing vibrations, since it is a valuable tool to discriminate between physically reasonable and artificial static electron densities. All of these mentioned suggestions can be applied as internal quality criteria. The last suggestion is based on the idea to initiate the experimental refinement with a set of model parameters, which is, as much as possible close to the final solution. This can be achieved by performing periodic boundary conditions calculations, from which theoretically created files are obtained, which contain the Miller indices (h, k, l) and the respective intensity I. This file is used for a model parameter estimation (refinement), which excludes vibrations. The resulting parameters can be used for the experimental refinement, where, in a first step, the density parameters are fixed to determine the parameters describing vibrations. For a fine tuning, again the electrostatic theorem and the other above mentioned suggestions could be applied. Theoretical predictions should not be biased by the method of computation. Therefore the dependence of the density analyzing tools on the level of calculation (method of calculation/basis set) and on the substituents in complex chemical bonding situations were evaluated in the second part of the present work. A number of compounds containing formal single and double sulfur nitrogen bonds was investigated. For these compounds, experimental data were also available. The calculated data were compared internally and with the experimental results. The internal comparison was drawn with regard to questions of convergency as well as with regard to questions of consistency: The resulting molecular properties from NBO/NRT analyses were found to be very stable, when the geometries were optimized at the respective level of theory. This stability is valid for variations in the methods of calculation as well as for variations in the basis set. Only the individual resonance weights of the contributing Natural Lewis Structures differed considerably depending on the level of calculation and depending on the substituents. However, the deviations were in both cases to a large extent within a limit which preserves the descending order of the leading resonance structure weights. The resulting bond orders, i.e., the total, covalent and ionic bond order from NRT calculations, were not affected by the shift in the resonance weights. The analysis of the bond topological parameters resulted in a discrimination between insensitive parameters and sensitive parameters. The stable parameters do neither depend strongly on the method of calculation nor on the basis set. Only minor variation occurs in the numerical values of these parameters, when the level of calculation is changed or even when other functional groups (H, Me, or tBu) are employed, as long as the methods of calculation do not drop considerably below a standard level. The bond descriptors of the sulfur nitrogen bonds were found to be also stable with respect to the functional groups R = H, R = Me, and R = tBu. Stable parameters are the bond distance, the density at the bond critical point (BCP) and the ratio of distances between the BCP and the nuclei A and B, which varies clearly when considering the formal bond type. For very small basis sets like the 3-21G basis set, this characteristic stability collapses. The sensitive parameters are based on the second derivatives of the density with respect to the coordinates. This is in accordance with the well known fact, that the total second derivative of the density with respect to the coordinates is a strongly oscillating function with positive as well as negative values. A profound deviation has to be anticipated as a consequence of strong oscillations. lambda3, which describes the local charge depletion in the direction of the interaction line, is the most varying parameter. A detailed analysis revealed that the position of the BCP in the rampant edge of the Laplacian distribution is responsible for the sensitivity of the numerical value of lambda3 in formal double bonds. Since the slope of the Laplacian assumes very high values in its rampant edge, a tiny displacement of the BCP leads already to a considerable change in lambda3. This instability is not a failure of the underlying theory, but it yields de facto to a considerable dependence of sensitive bond topological properties on the method of calculation and on the applied basis sets. Since the total second derivative is important to judge on the nature of the bond in the AIM theory (closed shell interactions versus shared interactions), the changes in lambda3 can lead to differing chemical interpretations. The comparison of theoretically derived bond topological properties of various sulfur nitrogen bonds provides the possibility to measure the self consistency of this data set. All data sets clearly exhibit a linear correlation between the bond distances and the density at the BCP on one hand and between the bond distances and the Laplacian values at the BCP on the other hand. These correlations were almost independent of the basis set size. In this context, the linear regression has to be regarded exclusively as a descriptive statistics tool. There is no correlation anticipated a priori. The formal bond type was found to be readily deducible from the theoretically obtained bond topological descriptors of the model systems. In this sense, the bond topological properties are self consistent despite of the numerical sensitivity of the derivatives, as exemplified above. Often, calculations are performed with the experimentally derived equilibrium geometries and not with optimized ones. Applying this approach, the computationally costly geometry optimizations are saved. Following this approach the bond topological properties were calculated using very flexible basis sets and employing the fixed experimental geometry (which, of course, includes the application of tBu groups). Regression coe±cients similar to those from optimized geometries were obtained for correlations between bond distances and the densities at the BCP as well as for the correlation between bond distances and the Laplacian at the BCP, i.e. the approach is valid. However, the data points scattered less and the coe±cient of correlation was clearly increased when geometry optimizations were performed beforehand. The comparison between data obtained from theory and experiment revealed fundamental discrepancies: In the data set of bond topological parameters from the experiment, the behavior of only 2 out of 3 insensitive parameters was comparable to the behavior of the theoretically obtained values, i.e. theoretical and experimental bond distances as well as theoretical and experimental densities at the BCP correlate. From the theoretically obtained data it was easy to deduce the formal bond type from the position of the BCP, since it changed in a systematic manner. The respective experimentally obtained values were almost constant and did not change systematically. For the SN bonds containing compounds, the total second derivative assumes exclusively negative values in the experiment. Due to the different internal behavior, experimentally and theoretically sensitive bond topological values could not be compared directly. The qualitative agreement in the Laplacian distribution, however, was excellent. In the third and last part of this work, the application to chemical systems follows. Formal hypervalent molecules, i.e. molecules where some atoms are considered to hold more than 8 electrons in their valence shell, were investigated. These were compounds containing sulfur nitrogen bonds (H(NtBu)2SMe, H2C{S(NtBu)2(NHtBu)}2, S(NtBu)2 and S(NtBu)3) and a highly coordinated silicon compound. The set of sulfur nitrogen compounds also contained a textbook example for valence expansion, the sulfur triimide. For these molecules, experimental reference values were available from high resolution X-ray experiments. The experimental results were in the case of the sulfur triimide not unique. Furthermore, from the experimental bond topological data no definite conclusion about the formal bonding type could be drawn. The situation of sulfur nitrogen bonds in the above mentioned set of molecules was analyzed in terms of a geometry discussion and by means of a topological analysis. The methyl-substituted isolated molecules served as model compounds. For the interpretation of the bonding situation additional NBO/NRT calculations were preformed for the sulfur nitrogen compounds and an ELF calculation and analysis was performed for the silicon compound. The ELF analysis included not only the presentation and discussion of the ELF-isosurfaces (eta = 0.85), but also the investigation of populations of disynaptic valence basins and the percentage contributions to these populations of the individual atoms when the disynaptic valence basins are split into atomic contributions according to Bader's partitioning scheme. The question of chemical interest was whether hypervalency is present in the set of molecules or not. In the first case the octet rule would be violated, in the second case Pauling's verdict would be violated. While the concept of hypervalency is well established in chemistry, the violation of Pauling's verdict is not. The quantitative numbers of the sensitive bond topological values from theory and experiment were not comparable, since no systematic relationship between the experimentally and theoretically determined sensitive bond descriptors was found. However, the insensitive parameters are in good agreement and the qualitative Laplacian distribution is, with few exceptions, in excellent agreement. The formal bonding type was deduced from experimental and theoretical topological data by considering the number and shape of valence shell charge concentrations in proximity to the sulfur and nitrogen centers. The results from NBO/NRT calculations confirmed the findings. All employed density analyzing tools AIM, ELF and NBO/NRT coincided in describing the bonding situation in the formally hypervalent molecules as highly polar. A comparison and analysis of experimentally and theoretically derived electron densities led consistently to the result, that regarding this set of molecules, hypervalency has to be excluded unequivocally.},
  subject      = {Elektronendichtebestimmung},
  language  = {en}
}
@phdthesis{Rapp2004,
  author    = {Rapp, Ulrike},
  title     = {Achieving protective immunitity against intracellular bacterial pathogens : a study on the efficiency of Gp96 as a vaccine carrier},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9096},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Protective vaccination against intracellular pathogens using HSP fusion proteins in the listeria model.},
  subject      = {Listeria monocytogenes},
  language  = {en}
}
@phdthesis{Lin2004,
  author    = {Lin, Chia-Huey},
  title     = {Functional characterization of rat CTLA-4 and CD25+CD4+ regulatory T cells},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8521},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2004},
  abstract  = {Summary: In the present work, two important negative regulators of T cell responses in rats were examined. At the molecular level, rat CTLA-4, a receptor important for deactivating T cell responses, was examined for the expression pattern and in vitro functions. For this purpose, anti-rat CTLA-4 mAbs were generated. Consistent with the studies in mice and humans, rat CTLA-4 was detectable only in CD25+CD4+ regulatory T cells in unstimulated rats, and was upregulated in all activated T cells. Cross-linking rat CTLA-4 led to the deactivation of anti-TCR- and anti-CD28 stimulated (costimulation) T cell responses such as reduction in activation marker expression, proliferation, and cytokine IL-2 production. Although T cells stimulated with the superagonistic anti-CD28 antibody alone without TCR engagement also increased their CTLA-4 expression, a delayed kinetics of CTLA-4 upregulation was found in cells stimulated in this way. The physiological relevance of this finding needs further investigation. At the cellular level, rat CD25+CD4+ regulatory T cells were examined here in detail. Using rat anti-CTLA-4 mAbs, the phenotype of CD25+CD4+ regulatory T cells was investigated. Identical to the mouse and human Treg phenotype, rat CD25+CD4+ T cells constitutively expressed CTLA-4, were predominantly CD45RC low, and expressed high level of CD62L (L-selectin). CD25+CD4+ cells proliferated poorly and were unable to produce IL-2 upon engagement of the TCR and CD28. Furthermore, rat CD25+CD4+ cells produced high amounts of anti-inflammatory cytokine IL-10 upon stimulation. Importantly, freshly isolated CD25+CD4+ T cells from na{\"i}ve rats exhibited suppressor activities in the in vitro suppressor assays. In vitro, CD25+CD4+ regulatory T cells proliferated vigorously upon superagonistic anti-CD28 stimulation and became very potent suppressor cells. In vivo, a single injection of CD28 superagonist into rats induced transient accumulation and activation of CD25+CD4+ regulatory T cells. These findings suggest firstly that efficient expansion of CD25+CD4+ cells without losing their suppressive effects (even enhance their suppressive activities) can be achieved with the superagonistic anti- CD28 antibody in vitro. Secondly, the induction of disproportional expansion of CD25+CD4+ cells by a single injection of superagonistic anti-CD28 antibody in vivo implies that superagonistic anti-CD28 antibody may be a promising candidate in treating autoimmune diseases by causing a transient increase of activated CD25+CD4+ T cells and thus tipping ongoing autoimmune responses toward selftolerance.},
  subject      = {Ratte},
  language  = {en}
}