Muhammed Hasan Aslan

A Novel Label-Free Optical Biosensor Using Synthetic Oligonucleotides from E. coli O157:H7: Elementary Sensitivity Tests

SiO2-TiO2 thin films for use as fiber optic guiding layers of optical DNA biosensors were fabricated by the sol-gel dip coating technique. The chemical structure and the surface morphology of the films were characterized before immobilization. Single probe DNA strands were immobilized on the surface and the porosity of the films before the hybridization process was measured. Refractive index values of the films were measured using a Metricon 2010 prism coupler. On the surface of each film, 12 different spots were taken for measurement and calculation of the mean refractive index values with their standard deviations. The increased refractive index values after the immobilization of single DNA strands indicated that immobilization was successfully achieved. A further refractive index increase after the hybridization with target single DNA strands showed the possibility of detection of the E. coli O157:H7 EDL933 species using strands of 20-mers (5′-TAATATCGGTTGCGGAGGTG -3′) sequence.

Effects of Mg doping on sol-gel derived nanocrystalline hydroxyapatite thin films

Abstract Both pure and Mg doped thin films were fabricated by sol–gel dip coating. The films were sintered either at 800 or 1000°C. The average grain size of the films was significantly affected by Mg substitution in the hydroxyapatite (HA) structure and change in the sintering temperature. The grains were considerably larger in the films sintered at higher temperatures. In addition, Mg doped films contained significantly larger grains compared to undoped HA films. Mg doping also caused rodlike grains at 800°C, and led to whitlockite (β-TCP) formation at 1000°C. The ratio of the existing phases was estimated as β-TCP/HA=27 : 73. All the films had rough surfaces with high porosity. It was also observed that undoped films had higher surface roughness than Mg doped ones.

DNA Biosensors for E. Coli O157:H7 Detection in Drinking Water Resources Using Sol-Gel Derived Waveguides

SiO2 -TiO2 thin films were fabricated by sol-gel dip coating technique to be used as the fiber optic guiding layers of optical DNA biosensors. The chemical structure of the films was examined by Fourier Transformed Infrared Spectroscopy (FTIR, Bio – Rad Tropical Option for FTS 175 C) and the surface morphology of the films was observed by Scanning Electron Microscopy (SEM, Philips XL 30 SFEG). The probe DNA was immobilized on the surface and the pores of the waveguide films before the hybridization process was carried out. By using Metricon 2010 prism coupler, 12 different spots were determined to be measured. Then the mean refractive index values and their standard deviations were calculated. The increased refractive index values after the DNA immobilization indicated that immobilization was successfully achieved. Further increase after the hybridization with complementary DNA showed the possibility of detection of the E. coli O157:H7 EDL933 species by using 20-mers (5’- TAATATCGGTTGCGGAGGTG-3’) sequence of GeneID: 957271.

Sintering behavior of ZnO: Mn ceramics fabricated from sol-gel derived nanocrystalline powders

Abstract Undoped and Mn doped ZnO ceramics, sintered at 1200 °C, were produced from sol-gel derived nanocrystalline powders calcined at 750 °C. Mn doped powders showed trace amounts of spinel (ZnMn2O4) phase in addition to a dominant zincite phase, while Mn doped ceramics were comprised solely of zincite structure. X-ray mapping of the powders did not reveal any Mn concentrated areas, indicating that the ZnMn2O4 phase was homogeneously distributed with a very small grain size. The grain size of the undoped powders was around 50 nm, and there was a minor increase in the grain size when powders were doped with Mn. Undoped ceramics exhibited grain sizes distributed in the range 2 – 10 μm while Mn doped ceramics displayed slightly smaller grains. Relative densities of the undoped and Mn doped ceramics were measured as 0.695 and 0.950, respectively.

Characterization and Electrical Properties of TiO[sub 2] Thin Films Deposited by Pulsed Laser Deposition

Thin film technology is very important in todays high‐tech industry. TiO2 is a high‐k dielectric material. Problems with thin film deposition arise when the thickness of the thin layers approaches a few hundred nm to less than 100 nm. High quality thin films within these dimensions are difficult to obtain. Issues of adhesion, crystal mismatch, crystal orientation, surface roughness, densification, etc. are problems that need to be addressed if good quality thin films for devices are to be fabricated. These factors have a relation with the thin film technique used. As an example, spin coating technique may be a cheaper technique but may not result in dense and very smooth surfaces. Pulsed LASER deposition (PLD) is a relatively newer method used in thin film fabrication. The advantages of PLD are, capability of very thin films being deposited on different types of substrates (up to monolayers), control of crystal orientation, capability of depositing materials with complex stoichiometry and ease of methodology with high throughput. This has industrial implications as a good method for thin film preparation. This work involves the deposition of TiO2 thin films using different deposition parameters and chamber environments.Thin film technology is very important in todays high‐tech industry. TiO2 is a high‐k dielectric material. Problems with thin film deposition arise when the thickness of the thin layers approaches a few hundred nm to less than 100 nm. High quality thin films within these dimensions are difficult to obtain. Issues of adhesion, crystal mismatch, crystal orientation, surface roughness, densification, etc. are problems that need to be addressed if good quality thin films for devices are to be fabricated. These factors have a relation with the thin film technique used. As an example, spin coating technique may be a cheaper technique but may not result in dense and very smooth surfaces. Pulsed LASER deposition (PLD) is a relatively newer method used in thin film fabrication. The advantages of PLD are, capability of very thin films being deposited on different types of substrates (up to monolayers), control of crystal orientation, capability of depositing materials with complex stoichiometry and ease of methodo...

Different Contributions of the φ→K[sup 0]K̄[sup 0]γ Decay

The scalar mesons and vector mesons contribution to the radiative decay φ→K0K0γ are studied within the framework of the phenomenological approach. The branching ratio of this decay is calculated to be 10−8–10−12. Furthermore, obtained values are compared with the experimental and theoretical results existing in the literature.The scalar mesons and vector mesons contribution to the radiative decay {phi}{yields}K{sup 0}K-bar{sup 0}{gamma} are studied within the framework of the phenomenological approach. The branching ratio of this decay is calculated to be 10{sup -8}-10{sup -12}. Furthermore, obtained values are compared with the experimental and theoretical results existing in the literature.