Bøger udgivet af Cuvillier

Die vorliegende Arbeit beschreibt die Identifizierung und Charakterisierung von Chemokin-bindenden Strukturen aus der Klasse der Peptide und Peptoide. Im ersten Teil wurde durch flexibles Protein-Protein Docking ein Modell des Rezeptor-Ligand-Komplexes des Chemokins CXCL8 mit seinem Rezeptor CXCR1 entwickelt, welches die in der Literatur vorgeschlagene Möglichkeit einer Wechselwirkung zwischen dem ELR Motiv von CXCL8 und den extrazellulären Domänen von CXCR1 bestätigt. Auf der Basis dieses Modells wurde durch Verknüpfung von zwei Ausschnitten aus der Sequenz von CXCR1 ein Peptid entworfen, welches CXCL8 mit einer Affinität von 500 nM bindet und die durch CXCL8 induzierte Migration von humanen neutrophilen Granulozyten inhibiert. Im zweiten Teil der Arbeit wurden one-bead-one-compound (OBOC) Bibliotheken von Peptoiden auf TentaGel Harz systematisch auf ihre Fähigkeit zur Bindung an fluoreszenzmarkiertes CXCL8 untersucht. Durch Optimierung der Screening-Parameter und Vereinfachung des Auswertungsprozesses mittels Analyse von fluoreszenzmikroskopisch erhaltenen Mischkanalbildern wurden 18 Peptoidsequenzen identifiziert, die CXCL8 mit mikromolaren Affinitäten binden.This work describes the identification and characterization of chemokine ligands of the compound classes of peptides and peptoids. In the first part of this work, a model of the receptor-ligand complex of the chemokine CXCL8 and its receptor CXCR1 was generated by flexible protein-protein docking. The model confirmed the possibility of an interaction between the ELR motif of CXCL8 and the extracellular domains of CXCR1, which was previously suggested by the literature. Based on this model, a peptide was designed by connecting two sequence motifs of CXCR1 in an attempt to mimic the receptor binding site. The peptide was determined to bind CXCL8 with an affinity of 500 nM and was found to inhibit CXCL8-induced migration of human neutrophil granulocytes. In the second part of this work, one-bead-one-compound (OBOC) libraries of peptoids on TentaGel resin were tested for their ability to bind fluorescently labelled CXCL8. By optimising screening parameters and by analysing microscopy images of the resin in two different fluorescence channels, 18 peptoids were identified that bind CXCL8 with micromolar affinities.

A sufficient supply of good quality drinking water is essential for health and productivity of livestock. In Jordan, goat production is an integral part of farming systems and plays a significant role for the food security of rural households. Jordan is one of the poorest countries in the world in terms of water availability with no positive prognosis due to its susceptibility to the impacts of climate change.This study evaluates the seasonal availability, quality, accessibility and utilization of goats¿ drinking water sources in different production systems of two agro-ecological zones in the Karak Governorate in southern Jordan, investigates the perception of farmers about breed differences with respect to their tolerance to water restrictions and production, and assesses the productive and economic performance of goats under different production systems and conditions of water availability with emphasis on water as a core element.Methods used comprised a questionnaire survey with 120 goat keepers, focus group discussions, laboratory analysis of water quality parameters, on-farm measurements of goat body weight and evaluation of body condition score.

This work presents a high-linearity automotive radar front-end at 77 GHz in 0.25 ¿m SiGe technology. The passive elements were realized using thin-film microstrip lines. A detailed transformer balun synthesis procedure was developed. The realized passive baluns (¿rat-race¿ and transformer) show excellent commonmode rejection ratios exceeding 30 dB and low losses of 2.5 dB. On the active side, a low-gain, high-linearity single stage common-emitter LNA was realized. The selected topology allowed finer trade-off between linearity and sensitivity of the front-end compared to multi-stage LNA solutions. For the mixer, a low-voltage supply, high-linearity, low-noise double-balanced concept was employed. It uses AC-coupling between the two stages, which allowed an independent optimization of transconductance, core sizing, and bias. The transconductance was designed for best noise performance, while the core was chosen for maximum linearity.A high-fidelity two-channel receiver was realized using these circuit components, which achieved a performance comparable to the published state-of-the-art results in SiGe: Single sideband noise figure better than 16.5 dB, 1 dB compression point exceeding -12 dBm, while consuming moderate 82 mA DC current from a 1.6 V supply for both channels.

Low genetic diversity in cauliflower is one of the big challenges that hinders plant breeders in developing cultivars that meet the different needs of farmers (high yield, high adaptation and resistance to biotic and abiotic stresses) and consumers (high quality). The most efficient way to improve the performance of cauliflower varieties is to access large, diverse pools of genetic material of this crop. Therefore, the overall aims of this thesis have been to assess the phenotypic and genotypic diversity of a broad collection of genebank cauliflower accessions, as well as to perform association mapping and genomic prediction on this crop.This study evaluated the performance of 200 genebank accessions of cauliflower at two farming system (organic and conventional) and over three growing seasons and genotyped them by genotyping by sequencing approach (GBS) to infer the population structure and genetic diversity. Also, this study investigated the potential of different modern molecular breeding methods in cauliflower , association mapping and genomic selection.The findings laid out in this thesis show that GBS could be used effectively for several tasks in the commercial improvement of cauliflower in particular and in B. oleraceae in general, without the need for imputation of missing values. These tasks include genetic diversity analysis, marker trait association and genomic prediction. Also, the current thesis affirms that both association mapping and genomic prediction have the potential to accelerate the genetic gain in cauliflower breeding programs. In addition, several promising genetic materials (for high yield and stability) were found, which could be used as starting materials in cauliflower breeding programs, and especially for organic farming.

This dissertation makes three contributions on local governance issues and public sector reforms. First, it explores a trade-off in the incentive effects induced by competitive funding schemes such as performance-budgeting or conditional grants. Using a game theoretical model, it is shown how efficiency enhancing effects and wasteful window-dressing incentives affect social welfare. The model derives important normative conclusions for the design of such funding schemes and discusses the advantages and drawbacks of different performance measures. Two empirical studies address the determinants and efficiency effects of intermunicipal cooperation among Hessian municipalities. Using survey data from Hessian municipalities, the author assesses how different municipal characteristics affect the occurrence of intermunicipal cooperation in labor-intensive administration services. The study places an emphasis on neighborhood specific factors. Using data from the municipal wastewater sector, the third study investigates efficiency effects of intermunicipal cooperation. The results from a nonparametric approach of efficiency analysis reveal that especially small municipalities may benefit from cooperation whereas medium-sized municipalities operate at efficient scale. It is likely, that X-inefficiencies and transaction costs outweigh cooperation gains from scale.

Due to its adaptation to extremely harsh environments, pearl millet (Pennisetum glaucum (L) R. Br.) is one of the most important staple cereals cultivated in the arid and semi-arid tropics of Asia and Africa. In these regions pearl millet is mainly produced under low-input, rainfed conditions in traditional farming systems, where several constrains are affecting pearl millet production, such as inter-annual rainfall variability, pests, diseases, Striga and use of low yielding varieties. The majority of the human population in these regions is affected by nutritional deficiencies of essential minerals causing micronutrient malnutrition (so-called ¿hidden hunger¿). Plant genetic resources provide basic materials for selection and improvement of crop productivity through the optimal design of breeding programs to meet food security needs of the world¿s rapidly rising population. The advent of PCR-based molecular markers such as simple sequence repeats (SSRs) has created an opportunity for fine-scale genetic characterization of germplasm collections. Understanding the structure of diversity and the identification of distinct materials with complementary traits for recombination by crossing provides the foundation for effective and sustained pearl millet population breeding and synthetic and hybrid development, based on the concept of heterotic groups in this allogamous crop.

This thesis is concerned with scheduling and three-dimensional packing problems that arise when restricting to nested intervals ¿ either for allocating jobs to time intervals (at machines) or for positioning boxes within a strip. The scheduling problems considered in the first part of this work are motivated by a real-world application in rail car maintenance, and result in a new type of job characteristic introduced into the methodology of scheduling. Being classified as strip packing problems on comparability graphs of an arborescence order, the packing problems of the second part of this thesis are further structurally characterized based on the concept of packing classes. It turns out that using this characterization, these packing problems can equivalently be solved by interval coloring adequate chordal graphs. For several variants of above-mentioned mathematical optimization problems complexity results are derived and approximation, pure heuristical as well as exact solution approaches presented. The performance of the approaches is finally discussed based on computational results.

Yersinia pseudotuberculosis is a human pathogen that causes acute intestinal and systemic diseases. This study investigated the link between pathogenic traits and the metabolic core machinery of Y. pseudotuberculosis using a systems biology approach: the integration of gene expression profiles with metabolic pathway fluxes in the wild type and virulence regulator mutants. The absence of specific virulence regulators particularly perturbed fluxes and gene expression of pyruvate metabolism and tricarboxylic acid cycle, suggesting an involvement of this metabolic node in the virulence management system. Mutants, genetically perturbed in regulators of this metabolic branch point and one of its central enzymes, showed a significant reduction of virulence in an oral mouse infection model. This revealed the pyruvate-TCA cycle node as a focal point for controlling host colonization. Flux rerouting was also identified as response to applied antibiotic therapies. The examination of Yersiniäs fine-tuned adaptation was expanded to temperature, an important infection parameter, using a continuous culture with advanced temperature control to mimic the infection process. The virulence regulator RovA, known to respond to temperature and to control metabolic, stress, and virulence genes, was quantified by Western blot analysis and fluorescence-activated cell sorting. RovA showed a bistable behavior that generally maximizes survival by heterogeneity.

Improved building insulation is an important part of today¿s efforts on energy saving. Here, nano-insulation materials promise especially low thermal conductivity. Therefore, an easy and cost-efficient production of these materials is an aim of present material research. One approach towards these materials is the expansion and fixation of polymerisable microemulsions of supercritical blowing agents. However, the nano-sized bubbles are found to undergo undesired coarsening processes. In order to reduce the increasing interfacial tension emerging during expansion and therewith the coarsening it was suggested to add low-molecular hydrophobic substances to the supercritical microemulsion. And indeed, the addition of cyclohexane to a microemulsion of the type brine ¿ CO2 ¿ fluorinated surfactants was found to reduce the fluorinated surfactant content ¿ a measure for the interfacial tension ¿ considerably. In this work a systematic small-angle neutron scattering (SANS) contrast variation was performed and the data were analysed by model-independent Fourier analysis. It was found that a concentration gradient of cyclohexane inside the CO2/cyclohexane microemulsion droplets forms. Interestingly, the analysis reveals a depletion zone close to the amphiphilic film which presumably develops due to the known repulsive interactions of cyclohexane and the fluorinated surfactant tails. Using a specially designed high pressure SANS cell to perform stroboscopic pressure jumps, the influence of cyclohexane on pressure-induced elongation of microemulsion droplets as well as the early state of foaming after expansion was studied. Here, the pressure-dependent thermodynamic stability of such microemulsions allows for a fast repeatability of the pressure cycles. It turned out that cyclohexane systematically slows down the structural changes in all processes. Parallel pressure jump experiments with poly-(N-isopropylacrylamide) (PNIPAM) particles revealed that hydration and dehydration kinetics can be studied with the same experimental setup. The first kinetic experiments which combine a CO2-microemulsion mixed with PNIPAM particles indicate that PNIPAM acts as a stabiliser for the microemulsion and further reduces the thermodynamic driving force of the demixing process.

Topological insulators (TIs) are a class of materials, which are insulating in the bulk but exhibit conductive states at the edges. These states are spin-polarized, protected against non-magnetic perturbations, and exhibit a linear dispersion. Due to these ¿topological¿ features, topological insulators may decisively contribute to the construction of spintronic devices.This book summarizes the results of an experimental Ph.D. thesis which aimed at finding methods for tailoring TIs. The first part provides an introduction to the field of topological insulators and the applied measurement techniques: STM and ARPES. In the second part, four experiments are presented in which different strategies to tailor the edge states were exploited. For the prototypical topological insulator Bi2Se3, it is shown that stoichiometric variations enhance the isolation of the edge state from the bulk band structure. Also for Bi2Se3, a method was found to introduce magnetic atoms (Fe) to the vicinity of the edge state which avoids any band bending effect. Furthermore, it is shown how edge states can be moved away from the surface of a TI. Creating a rough surface forces the edge state of TlBiSe2 to shift into the bulk. Finally it is shown how growing a Bi bilayer on Bi2Se3 shifts the edge state further out of the TI, where it interacts with bilayer states.The presented experiments prove the topological nature of these edge states and its consequences. The methods applied for the manipulation may allow a tailoring of topological insulators for future technological applications based on the spin degrees of freedom.

The futuristic vision of nanorobots performing various tasks not easily achieved by macroscopic machines has inspired the development of micron-sized swimmers and propellers that can be navigated with high precision at very small length scales. This thesis focuses on a particular class of such devices, magnetic helical particles, which are propelled using homogeneous rotating magnetic fields. I describe an optimized fabrication process based on the physical vapor deposition technique Glancing Angle Deposition, which allows the production of uniform colloids with complex shapes in very high yields. This process is extended to obtain magnetic helices with diameters below 100 nm. The resulting particles¿ propulsion behavior was observed experimentally, and compared with theoretical models. Furthermore two different strategies are examined for navigating not only simple Newtonian fluids, but also more complex biological fluids. In the first case, propulsion in hyaluronic acid is achieved by tuning the propellers¿ diameter to a size on the order of the medium¿s pore size. For the penetration of gastric mucin gels, a microorganism¿s propulsion strategy is mimicked, which relies on enzymatically changing the rheological properties of the local environment. These results illustrate the application of biomimetic locomotion tactics to artificial swimmers.

Der Wunsch der Menschen nach steigender Mobilität erfordert den weltweiten Ausbau/die weltweite Expansion des Flugbetriebs. Dabei ist nicht immer auszuschließen, dass Flugzeuge und Helikopter auch staubbelastetete Gebiete durchqueren müssen. Staub-/Sandansammlungen, wie sie bei/nach Vulkanausbrüchen oder z.B. durch Sand-Transport aus der Sahara und aus industriellen Quellen in der Atmosphäre vorkommen, stellen eines der Hauptprobleme für den vorzeitigen Verschleiß von Triebwerkskomponenten dar. Der Durchsatz scharfkantiger kristalliner Staub- und Sandpartikel erodiert die Oberflächen der Turbinenschaufeln und verändert Symmetrie und Abstimmung und somit die Effizienz des Triebwerks.Ziel dieser Doktorarbeit war die Entwicklung, Herstellung und experimentelle Untersuchung aufgedampfter Schichten (PVD = Physical Vapor Deposition) zur Anwendung hinsichtlich der Verlängerung der Lebensdauer von Komponenten in Gasturbinen. In einer Vakuum-Aufdampfanlage (PVD-Anlage) wurden ein- und mehrlagige Schichten auf ein Target aufgebracht und dieses anschließend in einem Erosionsprüfstand mit unterschiedlichen Parametern getestet. Aus der Analyse von Phasenentwicklung und der mechanischen Eigenschaften für die hergestellten Beschichtungen wurde versucht, eine Prognose über das Verschleißverhalten der Beschichtung zu erstellen. Die erodierten Schichten wurden im Raster-Elektronenmikroskop (REM) untersucht und unterschiedliche Verschleißmechanismen während des Erosionsprozesses besprochen. Die Ergebnisse werden ferner anhand theoretischer Modelle und der Nano-Indentierungs-Methode diskutiert.

The microthermoforming and respectively the SMART technology (Substrate Modification And Replication via Thermoforming) have proven to be a useful tool, which enables the fabrication of highly defined and reproducible polymer microchips with various depths and shapes. The microthermoforming and its modifications have facilitated development of configurations, which reflect relevant aspects of the in vivo conditions, with respect to morphology and essential biochemical and biophysical cues from the microenvironment or ¿niche¿. The film-based microstructures have unique properties such as small volume and mass, high flexibility, low heat capacity, thermal resistance and high permeability. Notably, the SMART ensures higher flexibility in terms of size and geometry of the polymer substrates, which are crucial for establishment of three-dimensional (3D) cell culturing models. Furthermore, such models might be an initial step towards development of more complex in vitro 3D platforms which can complement the conventional two-dimensional (2D) culturing systems by restating certain components of (stem) cells niches, including spatiotemporal control of dynamic cellular interactions or facilitating the formation of complex patterns in co-cultures, including in vitro tissue-similar models.The findings in this work provide support for key arguments that the SMART technology can successfully be employed as a major strategy for creating engineered scaffolds which could be assembled into platform for in vitro recapitulating the fundamental physiological properties from natural microenvironments of cells.

The Dissertation titled ¿Phytochemical analysis of Baby Banana peels (Musa acuminate) in relation with a hyperpigmentation phenomenon¿ described as a phytochemical analysis by means HSCCC (High-Speed Countercurrent Chromatography) supports that the climate change couldhave altered the Baby Banana quality and its metabolic behavior during the postharvest stage. Still, this is the first report of the analysis of a Baby Banana peels from Colombia in the scientific literature.

This study proposes solutions to determine a suitable mud pressure gradient window in real-time considering the HM- and THM-coupled effects. Six boundaries (FG, SFG, PPG, MHSG, RTFG and VSG) were employed to determine the mud pressure windows based on the failure mechanism of borehole wall. Models were developed to calculate the FG, SFG, and RTFG for different rocks under HM- and THM-coupled conditions. Sensitivity analyses were undertaken to categorize the input parameters into three groups, which were ¿must-have¿, ¿high-sensitive¿ and ¿low-sensitive¿ groups. To carry out a mud pressure window calculation in real-time, the ¿must-have¿ and ¿high-sensitive¿ parameters should be determined from logging data. The existing and relevant methods and empirical equations for calculating the UCS, IFA and PPG using logging data were analyzed and evaluated. Three methods for computing Biot¿s coefficient using logging data were developed. Two methods to estimate the horizontal in-situ stresses were also developed, one method was based on analyzing the breakout shape, and the other based on shear wave splitting. To investigate the thermal effects, a semi-analytical method was developed to simulate the depth-dependent temperature profiles in the annulus, tubing and surrounding rocks. Finally, two case studies were undertaken to verify the whole solutions of a suitable mud pressure window in real-time.

This thesis is focused on empirical examinations of commodity derivatives. Commodity futures and options are very important for companies in hedging their commodity price risks. Financial institutions participate also in commodity derivative markets either to gain exposure to commodity prices, diversify their portfolios, or hedge commodity price risk from financial transactions. But also retail investors have been more and more interested in commodity investments for some years. Because of their limited access to commodity markets, they have to rely on special commodity SFPs issued by banks. However, in contrast to derivatives with standard underlyings, such as stocks or bonds, there are various specific aspects to commodity derivatives. Especially interesting from academic as well as practitioners¿ point of view are the pricing relations between spot and derivative prices, which are closely linked to market fundamentals. But also from the financialization of commodity markets arise several subjects which require scientific examination. I identify in this thesis several unresolved research questions on commodity futures, options, and SFPs. This way it is possible to offer insights in derivative markets for industrial companies, financial institutions, and retail investors alike.

Large quantities of water are appropriated to produce the feed annually consumed in global livestock production. Rising concerns about increasing competition for water resources and projected increase in demand for livestock products make it imperative to look for strategies to sustainably increase livestock production, with water being one key natural resource to consider.Using a combination of different datasets, a mechanistic livestock model, and a dynamic vegetation model, we estimate the annual consumptive water use (CWU) in the global livestock sector associated with crops and fodder cultivated on cropland and grazed biomass from pastures.

Native carbohydrate fractions of major dietary components in pig nutrition, such as dietary fiber, resistant starch and oligosaccharides in whole cereal grains or grain legumes appear to be appropriate to manipulate the porcine gut microbiota. Therefore, the objective of this thesis was to evaluate effects of differences in carbohydrate composition of cereal grains, grain legumes and feed supplements on the intestinal microbiota in pigs. Based on a comprehensive literature research, an overview on the current research on the effect of whole grain cereals and grain legumes as well as their by-products on the pigs¿ intestinal microbiota in relation to their carbohydrate composition was given. An in vivo experiment was carried out to determine the effects of 8 recently introduced genotypes of barley or wheat on ileal and fecal microbiota of grower pigs by means of quantitative real-time PCR. In addition, in a second experiment the effect of ultra-fine ground fibers from wheat, lupins and peas in comparison to inulin and basal substrates on the microbiota composition and formation of microbial metabolites was determined in vitro using the modified Hohenheim Gas Test. In agreement with previous studies, the potential to modulate the pigs¿ intestinal microbiota with cereal grains and feed supplements based on cereal grain or grain legume fibers was shown. However, it was not possible to assign the observed effects on the bacterial groups to the dietary carbohydrates known to influence the intestinal microbiota, such as arabinoxylan or ¿-glucan.

Education is one of the key factors and basic driving force for the sustainable development of a society. From human¿s history, education and individual learning activities have been attached great importance and the research on education and learning has always continued generation by generation. With the rapid development of science, technology and social economy, as well as knowledge, skills, and improvement of the value of human capital, the status and role of education has been further improved and enhanced in the current era (Cheng 2009, S. 98). Education and learning has been entrusted with the new significances and meanings according to the rapid change and development of each aspect in the modern society. In the same time, the learning forms and styles have also changed and expanded to a much wider scope, not only limited to the traditional formal learning in schools or enclosed educational places or organizations, but also include different learning and educational forms, such as non-formal and even informal learning (Alheit 2009, S. 116).

The Report directed by James S. Coleman has mentioned that the effects of school resources on student achievement were weaker than those of students¿ families (Coleman et al. 1988, S. 95-120). The report also mentioned suggested that the performances and achievement by students have direct relationships with the family social and economic situations and conditions (Coleman et al. 1988, S. 95-120). Moreover, after discussing the influences based on the levels of students and schools to the learning achievement and performances, the results have shown obviously that the social and economic situations in the students¿ families have greater effects and influences, while the courses taught in the classroom and teachers¿ teaching experiences have little influences. Elliott (1998, S. 223-245) has found from the research work in the USA that the family and individuals¿ factors are much greater and more important than the school factors.

Socially organized animals have to synchronize the timing and directions of their movement decisions, in order to maintain group cohesion. To what extent social and environmental mechanisms trigger behavioural synchronization is still poorly understood. When housing management restricts space availability or predetermines feeding schedules, synchronization may develop as a random phenomenon due to external cues.This thesis investigated social and environmental determinants of behavioural synchronization in horses and sheep. Deeper understanding of what constitutes behavioural synchronization is essential in order to adequately classify behavioural changes related to synchronization, and to furthermore enable predictions of management problems in group housing of animals.

This researching is mainly focusing on the lifelong biographical experiences by different persons in China and Germany. The main researching method is biographical methods (Alheit 2009, S. 116) which take use of the interviews contents to do further and deeper analysis for the certain topics and themes. For this research, I have selected more than 20 interviewees in each country, with different social or learning background, and most of them could represent some certain kinds of groups in the society. With these interviewees, I have made interviews about their whole life process, especially the learning experiences and feelings until nowadays. Some of the narrative and interviewing contents are much more representative than others as they can stand for a different kind of learning and thinking type influencing by the schools learning factors and affairs, as well as the relating factors and materials. Therefore, from all the interviews, I have further selected 6 narrative contents in each country to make the comparison as follows. Each narration is a typical learning thought and idea which could be classified into a certain kind of social group. With the analyzing method and the basic notions of grounded theory (Alheit 1999, S. 1-19), this research has also made analysis based on the history, culture, law system, educational institutions, politician, social environment, etc. for each interview. The findings and researching results can offer new viewpoints and notions on the schools¿ influences and effects on learning motivations, behaviors, activities and even the lifelong learning process.