„Ich brauch dich, ich brauch dich nicht“

Die vorliegende Diplomarbeit befasst sich in Form einer Einzelfallstudie mit dem Erleben des vierjährigen Mädchens Amina im Kindergarten. Dabei sind zwei spezifische Aspekte in Aminas Verhalten auffällig: einerseits ihre Beziehungserfahrungen mit einer Gleichaltrigen und andererseits ihr Erleben von Abhängigkeit und ihr Streben nach Autonomie. Die Fragestellung, die in diesem Zusammenhang bearbeitet wird, setzt sich damit auseinander, welche Bedeutung die Beziehungserfahrungen, die Amina mit einer Gleichaltrigen im Kindergarten macht, für ihr Erleben von Abhängigkeit und ihr Streben nach Autonomie haben. Zunächst wird eine theoretische Hinführung zu der Thematik dieser Fragestellung dargestellt, welche die diesbezüglich bestehende Forschungslücke identifiziert. Die Grundlage für diese Einzelfallstudie über das Mädchen Amina bilden Beobachtungsprotokolle, die über einen Zeitraum von vier Monaten, mittels der Methode der Young Child Observation, in einem Kindergarten erhoben und anschließend, innerhalb einer Seminargruppe als auch einer Forschungsgruppe, analysiert wurden. Die Darstellung der Analyse des Beobachtungsmaterials nimmt einen zentralen Stellenwert in dieser Diplomarbeit ein. Abschließend werden die Ergebnisse der Einzelfallstudie Amina in Beziehung zu bestehenden Theorien gesetzt, um den wissenschaftlichen Ertrag dieser Arbeit auszuweisen.The present diploma thesis is in the form of a single case study and deals with the experiences of a four year old girl named Amina at a nursery. In this study, two particular issues in Aminas behaviour are remarkable: on one hand are her experiences in her relationship with a peer, and on the other, the experience of dependence and the aspiration to autonomy. The question, which will be addressed in this context, deals with the acceptance of the experiences that Amina makes with a peer in the nursery, and as aforementioned, centers on her dependence and her need for autonomy. In the beginning, a thematic introduction to the core of this question will be presented, which in turn, will identify the existing academic void. Observational reports make up the foundation of this single case study on Amina. All of the information was collected in the nursery of the child over the period of four months using the young-child-observation method. This information was then analysed within a seminar group as well as a research group. In conclusion, the results of the single case study on Amina will be correlated to existing theories, and shall account for the scientific portion of this paper

Ytterbium-doped Fiber-seeded Thin-disk Master Oscillator Power Amplifier Laser System

Lasers which operate at both high average power and energy are in demand for a wide range of applications such as materials processing, directed energy and EUV generation. Presented in this dissertation is a high-power 1 μm ytterbium-based hybrid laser system with temporally tailored pulse shaping capability and up to 62 mJ pulses, with the expectation the system can scale to higher pulse energies. This hybrid system consists of a low power fiber seed and pre-amplifier, and a solid state thin-disk regenerative amplifier. This system has been designed to generate high power temporally tailored pulses on the nanosecond time scale. Temporal tailoring and spectral control are performed in the low power fiber portion of the system with the high pulse energy being generated in the regenerative amplifier. The seed system consists of a 1030 nm fiber-coupled diode, which is transmitted through a Mach-Zehnder-type modulator in order to temporally vary the pulse shape. Typical pulses are 20-30 ns in duration and have energies of ~0.2 nJ from the modulator. These are amplified in a fiber pre-amplifier stage to ~100 nJ before being used to seed the free-space Yb:YAG thin-disk regenerative amplifier. Output pulses have maximum demonstrated pulse energies of 62 mJ with 20 ns pulse after ~250 passes in the cavity. The effects of thermal distortion in laser and passive optical materials are also. Generally the development of high power and high energy lasers is limited by thermal management strategies, as thermally-induced distortions can degrade laser performance and potentially cause catastrophic damage. Novel materials, such as optical ceramics, can be used to mitigate thermal distortions; however, thorough analysis is required to optimize their fabrication and minimize thermal distortions. iv Using a Shack-Hartmann wavefront sensor (SHWFS), it is possible to analyze the distortion induced in passive and doped optical elements by high power lasers. For example, the thin-disk used in the regenerative amplifier is examined in-situ during CW operation (up to 2 kW CW pump power). Additionally, passive oxide-based optical materials and Yb:YAG optical ceramics are also examined by pumping at 2 and 1 μm respectively to induce thermal distortions which are analyzed with the SHWFS. This method has been developed as a diagnostic for the relative assessment of material quality, and to grade differences in ceramic laser materials associated with differences in manufacturing processes and/or the presence of impurities. In summation, this dissertation presents a high energy 1 μm laser system which is novel in its combination of energy level and temporal tailoring, and an analysis of thermal distortions relevant to the development of high power laser systems

Ipvelutine, 7β-acetoxy-2α-(tigloyloxy)tropane, an unusual tropane alkaloid from Ipomoea velutina R. BR. (Convolvulaceae)

Convolvulaceae provide a rich source of tropane alkaloids, however, 2-substi-tuted tropanes have been described for only few species of this taxon. In this note, 2,7-diesters such as ipvelutine [7β-acetoxy-2α-(tigloyloxy)tropane] isolated from the vegetative parts of the Australian Ipomoea velutina R. BR. are described as a new group of tropane diesters

Melt Electrowriting of Graded Porous Scaffolds to Mimic the Matrix Structure of the Human Trabecular Meshwork

The permeability of the human trabecular meshwork (HTM) regulates eye pressure via a porosity gradient across its thickness modulated by stacked layers of matrix fibrils and cells. Changes in HTM porosity are associated with increases in intraocular pressure and the progress of diseases such as glaucoma. Engineered HTMs could help to understand the structure-function relation in natural tissues and lead to new regenerative solutions. Here, melt electrowriting (MEW) is explored as a biofabrication technique to produce fibrillar, porous scaffolds that mimic the multilayer, gradient structure of native HTM. Poly(caprolactone) constructs with a height of 125-500 μm and fiber diameters of 10-12 μm are printed. Scaffolds with a tensile modulus between 5.6 and 13 MPa and a static compression modulus in the range of 6-360 kPa are obtained by varying the scaffold design, that is, the density and orientation of the fibers and number of stacked layers. Primary HTM cells attach to the scaffolds, proliferate, and form a confluent layer within 8-14 days, depending on the scaffold design. High cell viability and cell morphology close to that in the native tissue are observed. The present work demonstrates the utility of MEW for reconstructing complex morphological features of natural tissues

Melt Electrowriting of Scaffolds with a Porosity Gradient to Mimic the Matrix Structure of the Human Trabecular Meshwork

The permeability of the Human Trabecular Meshwork (HTM) regulates eye pressure via a porosity gradient across its thickness modulated by stacked layers of matrix fibrils and cells. Changes in HTM porosity are associated with increases in intraocular pressure and the progress of diseases like glaucoma. Engineered HTMs could help to understand the structure-function relation in natural tissues, and lead to new regenerative solutions. Here, melt electrowriting (MEW) is explored as a biofabrication technique to produce fibrillar, porous scaffolds that mimic the multilayer, gradient structure of native HTM. Poly(caprolactone) constructs with a height of 125-500 μm and fiber diameters of 10-12 μm are printed. Scaffolds with a tensile modulus between 5.6 and 13 MPa, and a static compression modulus in the range of 6-360 kPa are obtained by varying the scaffolds design, i.e., density and orientation of the fibers and number of stacked layers. Primary HTM cells attach to the scaffolds, proliferate, and form a confluent layer within 8-14 days, depending on the scaffold design. High cell viability and cell morphology close to that in the native tissue are observed. The present work demonstrates the utility of MEW to reconstruct complex morphological features of natural tissues