The manufacturing of components with complex internal features, e.g. for automobile industry, aeronautics or medical applications, is a significant challenge. Such components are often machined in temporarily and locally separated stages of production. Due to these separated stages, the form deviations and positioning errors increase, which leads to additional efforts for the quality assurance. The technology that shall be developed within the project SwitchECM is supposed to enable machining of components with differing complex features in one single production stage and shall simultaneously allow for high precision. For this purpose, a multi-cathode system will be developed, in which every single cathode can be switched with specific parameters. The specific switching parameters shall be adjusted according to the requirements of the pre-defined features. For the manufacturing of different pre-defined features with one multi-cathode system the usage of pulsed direct current as well as continuous direct current shall be possible. Hence, removal experiments were carried out on 1.4301 stainless steel using a PEMCenter 8000 with varying feed rates and voltages at a pulsation frequency of 200 Hz. With this comparatively high frequency and a pulse duration of 4 ms pseudo direct current experiments are realized. The results are compared to experiments with a more common pulse frequency of 50 Hz. The mass removal analyses show, in which degree the transferability of experimental results from pulsed current to pseudo direct current or rather direct current is feasible.

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The gas assisted injection moulding process is an important extension to conventional injection moulding. Gas assist can be applied in a number of ways, but here the penetration of a gas bubble through the polymer melt is of interest. A 3D fi nite element implementation of a pseudo concentration method is employed to simulate the primary penetration of the gas bubble. The wall thickness prediction is an important result since the extent of bubble penetration is sensitive to the remaining melt fraction. A number of methods for experimental measurement are developed to measure characteristics of the gas assisted injection moulding process dynamics and product. Key process variables, on an industrial gas-assist machine, were measured and analysed, leading to an empirical model for wall thickness prediction. Gas delay time and injection velocity are shown to be most influential in controlling residual wall thickness. Simulation results are evaluated against the empirical model. The trends observed, for simulation and experiment, in wall thickness after changes in process variable settings are found to agree qualitatively. The wall thickness prediction is found to be within 10% of the experimentally obtained measurements.

Adhesive joining is an attractive alternative to conventional joining methods, such as welding and mechanical fastening. The benefits of adhesive bonding include: the ability to form lightweight, high stiffness structures; joining of different types of materials; better fatigue performance, and reduction in the stress concentrations or the effects of the heat associated with welding. However, concerns about the durability of adhesive joints still hinder their widespread use in structural applications. Moisture has been identified as one of the major factors affecting joint durability. This is especially important in applications where joints are exposed to varying moisture conditions throughout their useful life. The aim of this research is to develop models to predict degradation in adhesive joints under varying moisture conditions. This was achieved by a combination of experimental and numerical methods. Experiments were carried out to characterise the moisture uptake and mechanical properties of the single part epoxide adhesive, FM73-M. Single lap joints were manufactured from aluminium alloy 2024 in heat treated (T3) and non heat treated (O) states using the FM73-M, BR127 adhesive-primer system. Tensile testing of the single lap joints was carried out after the joints had been exposed to hot-wet conditioning environments. Models were developed for predicting moisture concentration in the adhesive under cyclic moisture absorption and desorption conditions. A finite element based methodology incorporating moisture history was developed to predict the cyclic moisture concentration. In the next step, a novel finite element based methodology, which was based on moisture history effects, was developed to determine stresses in bonded joints after curing, conditioning and tensile testing. In the final step, a moisture history dependent cohesive zone element based damage and failure criterion was introduced to predict damage initiation, crack growth and failure under variable moisture and temperature conditions. The methodology proposed in this work and its implementation by finite element method provides a systematic approach for determining the degradation in adhesive joints under varying environmental conditions and accomplishes the aim of this research.

Salvia genus is a widely cultivated genus and used in medicine for various purposes as having antimicrobial, antioxidant, anticarcinogen and anti-inflammatory features. In this study the aim was to investigate phenolic composition of Salvia absconditiflora and understand the possible effects of those constituents in cancer related drug metabolizing enzymes. Salvia absconditiflora showed 80,43 % Radical Scavenging Activity against DPPH radical. Total flavonoid content was found as one third of total phenolic content. Presence of important phenolic acids and flavonoids such as caffeic acid, luteolin, coumaric acid are validated with LC-MS/MS analysis. Cytotoxicity of Salvia absconditiflora treatment on MCF-7 and MDA-MB-231 breast cancer cell lines were investigated through XTT and TBE assays both dose and time dependent manner. Cell proliferation was inhibited 50 % by different IC50 values calculated in different assays and different time intervals. This suggests that two breast cancer cell lines response in a different way to cytotoxic treatments. Cancer related drug metabolizing enzyme gene modulations were investigated with qRT-PCR. CYP1A1 and CYP1B1 were upregulated in MCF-7 but down-regulated in MDA-MB-231 cells in response to Salvia absconditiflora treatment.

Salvia genus is a widely cultivated genus and used in medicine for various purposes as having antimicrobial, antioxidant, anticarcinogen and anti-inflammatory features. In this study the aim was to investigate phenolic composition of Salvia absconditiflora and understand the possible effects of those constituents in cancer related drug metabolizing enzymes. Salvia absconditiflora showed 80,43 % Radical Scavenging Activity against DPPH radical. Total flavonoid content was found as one third of total phenolic content. Presence of important phenolic acids and flavonoids such as caffeic acid, luteolin, coumaric acid are validated with LC-MS/MS analysis. Cytotoxicity of Salvia absconditiflora treatment on MCF-7 and MDA-MB-231 breast cancer cell lines were investigated through XTT and TBE assays both dose and time dependent manner. Cell proliferation was inhibited 50 % by different IC50 values calculated in different assays and different time intervals. This suggests that two breast cancer cell lines response in a different way to cytotoxic treatments. Cancer related drug metabolizing enzyme gene modulations were investigated with qRT-PCR. CYP1A1 and CYP1B1 were up-regulated in MCF-7 but down-regulated in MDA-MB-231 cells in response to Salvia absconditiflora treatment.

In this study, collagen based scaffolds were prepared for cornea tissue engineering. Three different cell carriers (rat tail collagen foam, insoluble collagen foam and patterned collagen film) were produced using two different collagen sources. Scaffolds were designed to mimic the unique topographical features of the corneal stroma. A novel crosslinking method was developed to achieve constant foam thickness. All scaffolds were tested with the primary cells of the native corneal stroma, human keratocytes. Although both foams promoted cell growth and penetration, rat tail foams were found to be superior for keratocyte proliferation. Their degradation rates were high enough but did not compromise their structural integrity during testing. Transparency studies with the foams revealed a progressive improvement. Collagen films degraded significantly over a one month period / however, the presence of cells increased the tensile strength of the films over a 21 day period to close to that of the native cornea and compensated for the loss of strength due to degradation. The micropatterned films proved to have higher transparency than the unpatterned scaffolds. In this study, it was possible to prepare collagen based micropatterned scaffolds using a silicon wafer and then a silicone template, successively, starting from original designs. The resultant collagen films were able to control cell growth through contact guidance, restricted cells and secreted-ECM within the pattern grooves, resulting in a higher transparency in comparison to unpatterned films. Thus, the tissue engineered constructs revealed a significant potential for use as total artificial corneal substitutes.

Turkey lies on one of major migratory routes between Palearctic and Afrotropical regions.Despite its importance for many species, few studies exist on bird migration over Turkey. In this study, autumn migration dynamics and stopover behaviour of Willow Warbler (Phylloscopus trochilus), a small insectivorous passerine, was documented and analyzed at Manyas KuScenneti National Park (northwestern Turkey). Birds were mistnetted, ringed, measured, weighed and fat-scored from mid August in 2002 and end of August in 2003 to end of October in both years. Totally 543 and 929 Willow Warblers were ringed in 2002 and 2003 respectively. For 2002 and 2003 respectively, fat score values (mean&plusmn / SE) are 4.63&plusmn / 0.06 and 3.84&plusmn / 0.05 and body mass values are 11.38&plusmn / 0.07 and 10.37&plusmn / 0.05 grams for birds captured the first time.Fat scores in 2003 show a bimodal distribution with peaks of T2 and T5, indicating populations or age classes with different migratory strategies.The number of retraps constituted 9.2-12.1 % of the total in 2002 and 2003. In both years,minimum stopover length ranged from 1 to 15 or 16 days with a median of 5 days. The majority of the retraps put on significant fat in both years. Retraps continued to put on weight for up to two weeks after they arrived. In this first ever study documenting passerine migration at Manyas KuScenneti National Park, it was revealed that such wetlands provide crucial stopover habitat for many migrant passerines, enables them to gain necessary fat loads before crossing two ecological barriers,the Mediterranean Sea and the Sahara.

Interactions of cholesterol reducing agent simvastatin with charged model membranes were investigated. Effects of cholestrol reducing agent simvastatin on the phase transition behaviour and physical properties of the anionic dipalmitoyl phosphatidylglycerol (DPPG) multilamellar liposome were studied as a function of temperature and simvastatin concentration. Moreover the effect of acyl chain length on the simvastatin model membrane interactions was monitored using dipalmitoyl phosphatidylglycerol (DPPG) and dimyristoyl phosphatidylglycerol (DMPG) lipids. All experiments were carried out by two non-invasive techniques namely Fourier Transform Infrared (FTIR) Spectroscopy and Differential Scanning Calorimetry (DSC). The observations made in the this study clearly showed that simvastatin interacts with the lipids of multilamellar liposomes and induces some variations in the structure of membranes. These effects are seen in the thermotropic phase transition profile of the membranes, on membrane order, acyl chain flexibility, lipid head group structures and membrane fluidity. The analysis of the C-H stretching region of FTIR spectra showed that, as simvastatin concentration increased, the phase transition curve broadened, pretransition temperature diminished, membrane order and membrane fluidity increased for anionic DPPG membrane. Moreover analysis of the C=O stretching and PO2 - stretching bands showed that simvastatin caused dehydration effect by decreasing of hydrogen bonding capacity in the glycerol backbone and also around the lipid head groups. DSC studies showed that as the simvastatin concentration increased, DSC curves broadened. In addition, simvastatin-induced lateral phase separation was observed in the DSC thermograms. In the second part of the study, the effect of acyl chain length on the simvastatin - membrane interactions was investigated for DPPG and DMPG lipid membranes. All parameters used in the FTIR studies are compared for DMPG and DPPG membranes. Similar results were observed for both membranes, except for the CH2 antisymmetric stretching band frequency at gel phase. Results showed that there are no significant effect of acyl chain length on simvastin - membrane interactions.

Amifostine is the only approved radioprotective agent by the Food and Drug Administration for reducing the damaging effects of radiation on healthy tissues. In this study, the effects of ionizing radiation on rat liver microsomal membrane and brain tissue and the protecting effects of amifostine on these systems were investigated at molecular level. Sprague-Dawley rats, which were administered amifostine or not, were whole-body irradiated and liver microsomal membranes and different regions of the brain of these rats were analyzed using FTIR spectroscopy, FTIR microspectroscopy and synchrotron FTIR microspectroscopy. The first part of this study revealed that ionizing radiation caused a decrease in the total lipid content and CH2 groups of lipids, an increase in the carbonyl esters, olefinic=CH and CH3 groups of lipids in the white matter and grey matter regions of the brain, which could be interpreted as a result of lipid peroxidation. In addition, radiation altered the protein structure of the brain. Amifostine caused significant protective effect against all the radiation induced damages in the brain. In the second part of the study, FTIR results showed that radiation induced a decrease in the lipid/protein ratio and a degradation of lipids into smaller fragments that contain less CH2 and more carbonyl esters, olefinic=CH and CH3 groups in microsomal membranes. In addition, radiation caused an alteration in the secondary structure of proteins, an increase in lipid order and a decrease in the membrane dynamics. Amifostine prevented all the radiation induced compositional, structural and functional damages in the liver microsomal membranes.