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    A study on radiation shielding properties, secondary radiation and radiation damage for composites containing glass fiber/PEEK/ gadolinium oxide
    (Pergamon-Elsevier Science Ltd, 2026) Erkoyuncu, I.; Maroc, F. Z.; Yilmaz, M.; Torun, T. R.; Ozdemir, H. G.; Ogul, H.; Akman, F.
    This study aimed to determine the gamma and neutron shielding capacities, the number of secondary gamma and neutrons produced after the primary neutron interaction together with their average energies and the damage caused by the incident gamma and neutron radiation on the composite for the composites containing glass fiber, PEEK and gadolinium oxide (Gd2O3). The theoretical approaches and/or simulation codes such as GEEANT4/FLUKA were used to determine these properties. It was observed that the gamma shielding capacity was improved for the studied composites with increasing Gd2O3 content. It was determined that the composite containing 50 % Gd2O3 (50GF50GdO), which was the highest studied amount, was superior to the others. The same composite also exhibited superior performance in removing fast neutrons. In addition, this composite has a fast neutron removal capacity that is 0.79 times higher than paraffin and 1.77 times higher than ordinary concrete. In terms of neutron shielding, the composite containing 50 % PEEK showed better performance at low energies, while 50GF50GdO replaced with this composite at high energies. It was determined that the composite coded as 50GF50GdO was less risky than the other composites in terms of both secondary gamma and secondary neutron formation. Finally, it was observed that as the energy of both gamma and neutron radiation increased, the studied composites were exposed to more radiation damage.
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    Antenna-type radiofrequency generator in nanoparticle-mediated hyperthermia
    (Royal Soc Chemistry, 2016) Nasseri, B.; Yilmaz, M.; Turk, M.; Kocum, I. C.; Piskin, E.
    Induction of hyperthermia using nanoparticles with specific magnetic, electrical, acoustic, optical or thermal properties is a potential alternative to conventional thermal ablation in cancer therapy. In this study, for the first time we employed an antenna-type radiofrequency (RF) generator as the energy source and as a proof of concept the effects of nanoparticles of varying structures and sizes, such as super-paramagnetic iron oxide nanoparticles (SPIONs), gold-coated superparamagnetic iron oxide nanoparticles (Au@SPIONs), spherical gold nanoparticles (AuNPs), and gold nanorods (AuNRs) on RF hyperthermia were examined to determine hyperthermia efficiency of the antenna-type RF generator. In preliminary experiments, RF was applied at varying powers to various nanoparticle solutions. In all cases, temperature rises due to exposure of RF radiation to nanoparticles were captured by using an infrared thermal camera. This procedure was applied to in vitro tests of fibroblast (L-929) and breast cancer (MCF-7) cell lines. Cell viability, apoptosis and necrosis were evaluated in both cell lines to comprehensively determine cell toxicity. Due to their particle size and chemical nature, SPIONs, in the case of highest RF power and nanoparticle concentration, resulted in the lowest cell viability and highest levels of apoptosis and necrosis.
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    Efficiency of ascorbic acid against oxidative stress-induced dimethoate toxicity in fish, Capoeta capoeta [Guldenstaedt, 1773]
    (Triveni Enterprises, 2017) Yilmaz, M.; Kaya, I.; Koc, E.; Tanriverdl, E. A.; Kaya, M. M.; Ersan, Y.
    Aim: The main objective of the present study was to evaluate the effect of ascorbic acid against oxidative stress-induced by dimethoate in Capoeta capoeta. Methodology: The fish caught in Kars Creek were randomized in four equal groups and acclimatized in separate tanks. The fish were kept in tanks for 10 days as follows: Group I (control) was kept in normal water, Group II, Ill and IV were kept in separate tanks containing 2 mgrdimethoate and 2 mgr dimethoate plus 100 mgr' ascorbic acid and ascorbic acid. The level of total sialic acid, total antioxidant status and total oxidant status in fish serum were analyzed. Results: Total sialic acid level of Group III was found to be lower than the level of Group II (P< 0.05), there were no statistically important differences between these two groups in total antioxidant status and oxidant status. In gills, intensive cartilage degenerations and mononuclear cell infiltrations in group II and III were observed. It was found that toxic effects of dimethoate in group III decreased. Interpretation: Ascorbic acid in fish exposed to dimethoate reduced the level of total sialic acid and degenerations in lamellae of gills, it had no significant effect on the oxidative stress response. [GRAPHICS] .
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    The fabrication of plasmonic nanoparticle-containing multilayer films via a bio-inspired polydopamine coating
    (Royal Soc Chemistry, 2016) Yilmaz, M.; Bakirci, G.; Erdogan, H.; Tamer, U.; Demirel, G.
    Herein, we introduce a simple approach for the fabrication of plasmonic nanoparticle-containing multilayer films using a bio-inspired polydopamine coating. This fabrication methodology represents a promising new development in the future application of plasmonic films in sensing and catalysis applications.