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Yayın Time evolution of film formation from polystyrene particles: a percolation approach(Springer, 2005-12) Uğur, Şaziye; Pekcan, Mehmet ÖnderThis work reports the film formation process from surfactant-free polystyrene (PS) latex particles. Steady state fluorescence and photon transmission techniques were used to study the evolution of film formation. The films were prepared from fluorescein (F)-labeled PS latex particles at room temperature and annealed in 2.5-min-time intervals above the glass transition temperature (T-g) of PS. Fluorescence intensity (I-F) from F was measured after each annealing step to monitor the stages of film formation. Evolution of transparency of latex films was monitored by using the photon transmission intensity, I-tr. Drastic increase in I-tr and I-F above the critical annealing times t(r) and t(c) respectively, were attributed to the percolation behavior of the PS material. Critical exponents, beta, of percolation clusters were measured and found to be around 0.31 and 0.37 for Itr and IF measurement, respectively, which were attributed to the site percolation model.Yayın Evaluation of satisfaction with a questionnaire according to fracture level and fracture type of patients who underwent balloon kyphoplasty(Galenos Publishing House, 2022-04) Kültür, Yiğit; Bal, Emre; Erdem, Mehmet Nuri; Tezer, MehmetObjective: The aim of this study is to better understand which type of fracture and localization have more painful or worse outcomes for the kyphoplasty procedure. Materials and Methods: Kyphoplasty cases operated between 2013 and 2018 were included in the study. The patients were contacted through the numbers registered in the hospital system. A questionnaire were asked to the patients. Patients were grouped according to gender, fracture level (T12-L1 and others) and fracture type (Osteoporotic, trauma, malignancy, unknown). Results: Fourty-one patients were included in the study. Three-quarters of the patients were women and average age was 62. Ninety-two percent of the patients stated that the pain of the procedure was tolerable. Seventy percent reported that their pain decreased after the procedure and 75% of the patients stated that they could have this procedure done again. Pain reduction and the desire to have same surgery again were significantly higher in female patients than in the male group (p<0.05). In the T12-L1 group and osteoporotic fracture group, the procedure was more easily tolerated, the pain was relieved more and the desire to have the same surgery was higher (p<0.05). Conclusion: Kyphoplasty is accepted as an operation that is well tolerated by patients and has good pain relief. Additionally more detailed information was obtained about the patient’s complaints after the kyphoplasty procedure, according to the fracture level and type.Yayın Film formation stages for poly(vinyl acetate) latex particles: a photon transmission study(Springer-Verlag, 2006-07) Kara, Selim; Pekcan, Mehmet Önder; Saraç, Ayfer; Arda, ErtanPhoton transmission technique was used to monitor the evolution of transparency during film formation from poly(vinyl acetate) (PVAc) latex particles. The latex films were prepared below the glass transition temperature (T-g) of PVAc. These films were annealed at elevated temperatures in various time intervals above the T-g of PVAc. It is observed that transmitted photon intensity (I-tr) from these films increased as the annealing temperature is increased. It is seen from I (tr) curves that there are two film formation stages. These successive stages are named void closure (viscous flow) and interdiffusion. The activation energies for viscous flow (Delta H) and backbone motion (Delta E (b)) were obtained by using well-defined models. The averaged values of the backbone (Delta E (b)) and the viscous flow activation energies (Delta H) were found to be 188.6 and 5.6 kcal/mol, respectively. The minimum film formation (tau (M),T (M)) and healing points (tau (H),T (H)) were determined. Minimum film formation (Delta E (M)) and healing activation energies (Delta E (H)) were measured using these time-temperature pairs. Delta E (M) and Delta E (H) were found to be 32.5 and 28.3 kcal/mol, respectively.Yayın Reversible film formation from nano-sized PNIPAM particles below glass transition(Springer-Verlag, 2007-01) Uğur, Şaziye; Elaissari, Abdelhamid; Yargı, Önder; Pekcan, Mehmet ÖnderReversible film formation process from nano-sized Poly(N-isopropylacrylamide) (PNIPAM) microgel particles were studied during heating-cooling cycles at various rates. Photon transmission technique was used and transmitted photon intensity I (tr) was monitored during heating-cooling cycles. The increase and decrease in I (tr) during heating and cooling was explained with the void closure and void reconstruction processes, and the corresponding activation energies were measured. It was observed that PNIPAM microgels required less energy during reconstruction of voids than their closure.
