Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Circulating Nucleic Acid (cna) Separation From Serum by Electrospun Membranes(Izmir Institute of Technology, 2015) Işık, Tuğba; Isık, Tuğba; Demir, Mustafa Muammer; Demir, Mustafa Muammer; Horzum Polat, Nesrin; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyEarly detection of diseases is a key factor that can be made provision and successfully treated. There is a wide array of methods to diagnose cancer like biopsy, endoscopy, magnetic resonance imaging (MRI) and blood tests. In blood, while some nucleic acids are found in intracellular fluids, circulating nucleic acids (CNAs) circulate freely in extracellular fluids. They are located at genomic regions and increased levels of CNAs imply a connection with cancer and tumor initiation. For further analysis, separation and concentration of CNAs have high potential in early cancer detection. A model system was constructed with bovine serum albumin (BSA) and single stranded Deoxyribonucleic acid (ss-DNA) for the investigation of membrane separation efficiency. The membranes made of poly styrene (PS) and poly(methylmethacrylate) (PMMA) were fabricated by electrospinning and they were placed in syringe columns. By using the absorption spectroscopy, the sorption efficiency of membranes was determined. The electrospun membranes are promising for BSA uptake over a wide pH range. Under the same circumstances, thanks to PS fibers, ss-DNA uptake is very with respect to BSA uptake. Our results revealed that PS membranes show a better affinity to BSA molecules by hydrophobic interactions. In the mixture of BSA and ss-DNA, ss- DNA cannot be held on the surface of the membrane and pass through with low sorption efficiency. By altering the membrane amount in syringe column and modifiying the surface of the membranes, the separation could be enhanced. The proposed technology promises fast and effective separation of CNAs from whole blood and body fluids.Master Thesis Synthesis and Characterization of Mgb2 Superconducting Wires(Izmir Institute of Technology, 2008) Horzum Polat, Nesrin; Özgen, İsmet Tamerkan; Özgen, Tamerkan; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyIn this study, the superconducting properties of laboratory synthesized MgB2 was investigated. In the first part, MgB2 synthesis using commercial magnesium and boron (95-97% purity), and its microstructural and electrical characterization was investigated.Effects of sheath material and annealing temperatures were also examined. The microstructural studies showed that when Cu tubes were used as sheath material, MgCu2 forms instead of MgB2 even at 700oC, while on Fe clad cores, the major phase was MgB2 with minor MgO constituent. The transition temperatures of Fe clad wires were measured between 39K and 40K, whereas no transition temperature was observed for Cu clad wires. The Ic value of the Fe clad MgB2 wire was about 25 A at 4K, while the copper clad wire could not carry current and formed resistance. In Fe clad wires, better results were obtained at annealing temperature of 800°C for 30 minutes. In the second part, MgB2 synthesis using commercial magnesium and boron (90% purity) was tried. 0-5-10-15 wt% of Mg doping and, additionally annealing temperatures were examined. Powder-In-Tube method was used for wire production. 10 wt% Mg addition was seen to be beneficial as compared to the stoichiometric MgB2. 750°C was found to be the most suitable temperature for the formation of MgB2 phase. The Ic value of the wire was measured as 13 A at 4K and it showed a broader transition with non-zero resistivity, transition temperature of 24K.In the third part, 200 m long four filament MgB2/Cu wire was successfully produced in laboratory conditions.