Hilal Goktas

Optical phase distribution evaluation by using an S-transform

An experimental study of the use of an S-transform to evaluate the phase distribution from a two-dimensional fringe pattern by introducing the carrier frequencies in two spatial directions, x and y, is presented. The phase distribution is extracted from the optical fringe pattern by using an S-transform gradient and S-transform phase methods. The experimental result for the Fourier transform profilometry algorithm is compared with the results of the S-transform analysis.

Plasma Polymerized Calixarene Thin Films and their Sensing Properties to Chloroform Vapors

The production of calixarene thin films via double discharge plasma technique and their sensitivity towards chloroform vapor are presented here in. The calixarene thin film is fabricated for the first time by plasma polymerized technique. Each experiment carried out at room temperature, at 0.6 mbar operating pressure, 2.0 kV DC and 19 kV pulsed voltages. From the UV-vis spectra it is observed that the polyconjugated structure is established and the thin films highly possess the characteristic bands of the oligomer. The SPR results revealed that the films thickness is at the order of several nm and the refractive index range from 2.2 to 2.8. The QCM results show that the thin films are highly sensitive with a fast and reversible adsorption to chloroform. The typical response time was of a few seconds.

Plasma Copolymerization of Thiophene and Pyrrole

The copolymerization of thiophene and pyrrole thin films synthesized by using a double discharge technique which has a fast filamentary discharge formed from the superposition of an ordinary low-pressure dc glow discharge and a high-current pulsed one is presented. Quartz glass substrates were coated at a pressure of 0.8 mbar and 19-kV pulsed and 2-kV dc potentials. The analysis of functional groups by FTIR spectrometry showed that the molecular structure of the copolymerized thin films with the filamentary discharge part almost preserves the conventional polymeric structure.

Improved Bone Formation in Osteoporotic Rabbits with the Bone Morphogenetic Protein-2 (rhBMP-2) Coated Titanium Screws Which Were Coated By Using Plasma Polymerization Technique

Abstract Delaying of bone fusion in osteoporotic patients underwent spinal stabilization surgery leads to screw loosening, and this causes pseudoarticulation, mobility and fibrosis at vertebral segments. To prevent these complications, the screws coated with recombinant bone morphogenetic protein-2 (rhBMP-2) could be used. To verify this hypothesis, we coated 5 Titanium screws with rhBMP-2 using plasma polymerization method, and also used 10 uncoated screws for making comparison between coated and uncoated screws in different groups. And 15 skeletally mature white New Zealand female rabbits were assigned into three different groups: Group 1(N = 5): No osteoporosis induction and insertion of uncoated Titanium screw into right sacrum of each rabbit in group 1; group 2 (N = 5): Osteoporosis induction and insertion of uncoated Titanium screw into right sacrum of each rabbit in group 2; group 3 (N = 5) rhBMP-2 coated Titanium screw inserted into right sacrum of each rabbit in group 3. In summary, using of these coated screws provides new bone formation, but causes less fibrosis and less inflammation than uncoated screws at the interface between the coated screw and bone. Then the plasma polymerization technique provides controlled releasing of rhBMP-2 from the screw to the bone tissue in osteoporotic rabbits.

Plasma polymerized composite thin films produced by double discharges technique

We report herein the characterizations of thiophene and pyrrole composite thin films synthesized by using a plasma based electron beam generator which has a fast filamentary discharge formed from the superposition of an ordinary low-pressure dc glow discharge and high-current pulsed one. Glass and ITO (indium tin oxide) substrates were coated at a pressure of 1 mbar, 19 kV pulsed and 2 kV dc potential. The substrates were located at different regions in the reactor to evaluate the influence of the position on the molecular structure of the obtained thin films. To our knowledge, such composite thin films are synthesized for the first time by such technique.