Parmaksiz A.,Ankara Nuclear Research And Training Center
Radiation Protection Dosimetry | Year: 2016
Cosmic radiation doses of individuals living in 81 cities in Turkey were estimated by using CARI-6 software. Annual cosmic radiation doses of individuals were found to be between 308 and 736 μSv y-1 at ground level. The population-weighted annual effective dose from cosmic radiation was determined to be 387 μSv y-1 for Turkey. Cosmic radiation doses on-board for 137 (60 domestic and 77 international) flights varied from 1.2 to 83 -1Sv. It was estimated that six or over long-route round-trip air travels may cause cosmic radiation dose above the permissible limit for member of the public, i.e. 1 mSv y-1. According to the assumption of flights throughout 800 h on each route, cosmic radiation doses were found to be between 1.0 and 4.8 mSv for aircrew. © The Author 2015. Published by Oxford University Press. All rights reserved.
Kantoglu O.,Ankara Nuclear Research And Training Center
Radiochimica Acta | Year: 2017
Degree of decolorization due to the irradiation of aqueous solutions of commercial cationic (basic) Astrazon Black FDL textile dye was studied in this study. Factor effecting radiolysis of the dye such as dye concentration, absorbed dose, toxicity, COD, BOD5 and pH of solutions were studied at air, O2 saturated and H2O2 environments. Unirradiated Astrazon Black FDL was non-biodegradable, whereas it was biodegradable after irradiation. The biodegradability (BOD5/COD) increased at 2 kGy for Astrazon Black FDL in all solutions. The biorefractory organic compounds were converted into more easily biodegradable compounds having lower molecular weights. In optimum dose and pH determination experiments, 5 kGy pH 12 at air, 7 kGy pH 3 at O2 saturated, 9 kGy pH 3 at 2.6 mM H2O2 for Astrazon Black FDL were found as the optimum irradiation conditions. Toxicity level of unirradiated solutions was high, whereas toxicity level of irradiated solutions was lower. © 2017 Walter de Gruyter GmbH, Berlin/Boston.
Hazirolan D.,Ankara Nuclear Research And Training Center |
Pleyer U.,Humboldt University of Berlin
Ophthalmic Research | Year: 2013
The eye is probably the most attractive site of the body for treatment using locally delivered therapeutic agents. An ideal indication for such an approach is noninfectious posterior uveitis. Since intraocular structures of the posterior segment are difficult to reach and are otherwise accessible only by systemic treatment, current interest is focused on the pros and cons of intravitreal drug delivery. Because of its chronic and recurrent nature, the long-term release of anti-inflammatory agents is a major treatment goal. Intravitreal injections, intravitreal implants and biodegradable devices are the most commonly used and approved approaches to deliver various agents to the vitreous. Because of their broad and potent effects, corticosteroids (CS) have been the first-line candidates for intraocular delivery. An increasing spectrum of CS preparations including nondegradable and biodegradable devices is currently available. Since repeated and long-term applications bear the risk of steroid-related complications such as increased intraocular pressure and cataract, alternative agents are currently being tested. Intravitreal injection of methotrexate, anti-VEGF (vascular endothelial growth factor), anti-TNFα (tumor necrosis factor α) and sirolimus have also been applied in patients with conflicting results. Intravitreal treatment has significantly reduced the incidence of adverse effects compared to systemic application, but due to greater ocular side effects there are still some limitations. © 2012 S. Karger AG, Basel.
Tugluoglu N.,Ankara Nuclear Research And Training Center |
Karadeniz S.,Ankara Nuclear Research And Training Center
Current Applied Physics | Year: 2012
The electrical and interface state properties of Au/perylene-monoimide (PMI)/n-Si Schottky barrier diode have been investigated by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. A good rectifying behavior was seen from the I-V characteristics. The series resistance (R s) values were determined from I-V and C-V characteristics and were found to be 160 Ω and 53 Ω, respectively. The barrier height (Φ b) of Au/PMI/n-Si Schottky diode was found to be 0.694 eV (I-V) and 0.826 eV (C-V). The ideality factor (n) was obtained to be 4.27 from the forward bias I-V characteristics. The energy distribution of interface state density (N ss) of the PMI-based structure was determined, and the energy values of N ss were found in the range from E c - 0.508 eV to E c - 0.569 eV with the exponential growth from midgap toward the bottom of the conduction band. The values of the N ss without R s are 2.11 × 10 12 eV -1 cm -2 at E c - 0.508 eV and 2.00 × 10 12 eV -1 cm -2 at E c - 0.569 eV. Based on the above results, it is clear that modification of the interfacial potential barrier for metal/n-Si structures has been achieved using a thin interlayer of the perylene-monomide. © 2012 Elsevier B.V. All rights reserved.
Zeyrek T.C.,Ankara Nuclear Research And Training Center
Journal of the Korean Chemical Society | Year: 2013
Optimized geometrical structure, atomic charges, molecular electrostatic potential, nonlinear optical (NLO) effects and thermodynamic properties of the title compound N-(2,5-methylphenyl)salicylaldimine (I) have been investigated by using ab initio quantum chemical computational studies. Calculated results showed that the enol form of (I) is more stable than keto form. The solvent effect was investigated for obtained molecular energies, hardneses and the atomic charge distributions of (I). Natural bond orbital and frontier molecular orbital analysis of the title compound were also performed. The total molecular dipole moment (μ), linear polarizability (α), and first-order hyperpolarizability (β) were calculated by B3LYP method with 6- 31G(d), 6-31+G(d,p), 6-31++G(d,p), 6-311+G(d) and 6-311++G(d,p) basis sets to investigate the NLO properties of the compound (I). The standard thermodynamic functions were obtained for the title compound with the temperature ranging from 200 to 450 K.
Aksu E.,Ankara Nuclear Research And Training Center
Journal of Alloys and Compounds | Year: 2013
MgB2 phase formation of samples with stoichiometric ratio of 1:2, prepared by sintering at different nine temperature values (500-900 °C) for 1 h were determined and examined by X-ray Diffractometry (XRD), Scanning Electron Microscopy (SEM) methods. In order to support the results obtained from the above measurements and analyses the Mg:B (1:2) powder was subject to thermal studies. In conjunction with this, the thermal behaviors of the non-sintered powder samples were also studied their characteristics via thermal analysis techniques including Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) simultaneously. During the thermal analyses, Mg:B (1:2) powder was placed in an Al2O3 cup with a lid were investigated at different heating rates (5, 7.5, 10, and 15°C/min) under high-purity Argon atmosphere. By analyzing the graphics gathered from the measurement results the effect of fundamental thermal events on MgB2 phase formation was deeply discussed by considering some data such as, crystallization, melting point, oxidation and evaporation, which can mainly be obtained from a usual thermal analysis technique. The peak temperatures of exothermic lines in DSC curves that indicate the formation of MgB2 were determined by derivative lines of the curves. With help of this information, the value of activation energy of MgB2 phase was found as EMgB2 = 219.9 kJ/mol by Kissinger Method. Moreover, in order to study the superconductivity of the samples; the sample sintered at 900 °C which was showing a considerable single phase property, was chosen for AC susceptibility measurement. For this sample, the onset temperature which is also called the transition temperature for superconductivity phase was found as Tc = 38.7 K. © 2012 Elsevier B.V. All rights reserved.
Karacan F.,Ankara Nuclear Research And Training Center
Journal of Radioanalytical and Nuclear Chemistry | Year: 2011
Determination of 90Sr in environmental solid samples is a challenging task because of the presence of so many other radionuclides in samples of interest. This problem was dealt with by radiochemical separation of strontium followed by yttrium separation and Cerenkov counting of the high-energy β-particle emissions of 90Y in order to quantitate 90Sr. In this work, an improved method is described for the determination of 90Sr in soil samples, through the separation of the daughter 90Y at equilibrium. The procedure is based on the HDEHP solvent extraction in combination with liquid scintillation spectrometry (LSS). A low background Quantulus has been optimized for low level counting of Cerenkov radiation emitted by the hard β-emitter 90Y. The analytical quality of the method has been checked by analyzing IAEA Soil-375 reference materials. The analytical method has also been successfully applied to the determination of 90Sr for moss-soil samples in inter-laboratory exercises through IAEA's ALMERA network. The chemical recovery for 90Y extraction ranged from 80 to 85% and the counting efficiency was 73% in the window 25-400 keV. © 2011 Akadémiai Kiadó.
Parmaksiz A.,Ankara Nuclear Research And Training Center
Radiation Protection Dosimetry | Year: 2013
The analysis of 226Ra, 232Th and 40K radionuclides has been carried out in geothermal water and residue samples collected from six wells of geothermal power plant and disposal site, using gamma-spectrometry system equipped with a high-purity germanium detector. The activity concentrations of nine geothermal water samples were found to be lower than minimum detectable activity (MDA) values. The activity concentration of the residue samples ranged from 40±4 to 2694±85 Bq kg-1 for 226Ra, 33±4 to 2388±85 Bq kg-1 for 226Th, and MDAvalue to 967±30 Bq kg-1 for 40K. In the study, some radiological indexes were examined and found to be higher than the reference values for majority of the residue samples. The annual effective doses arising from some residue samples were calculated to be higher than the permitted dose rate for the public, i.e. 1 mSv y-1. © The Author 2013. Published by Oxford University Press. All rights reserved.
Akduran N.,Ankara Nuclear Research And Training Center
Journal of Low Temperature Physics | Year: 2012
The Y 3Ba 5Cu 8O 18 superconductors are synthesised using the solid state reaction method under different annealing conditions. Structure characterisation using X-ray diffraction shows that the lattice parameters are different from those of the standard YBCO system. The resistivity measurements are performed using the four-probe method in the temperature range from 77 to 300 K. The electrical resistivity indicates the transition temperature T c (O 2) = 100.2 K and T c (air) = 92.3 K. Thermal fluctuations were experimentally studied. The correlations of the critical exponents with the dimensionality of the fluctuation system for each Gaussian regime were performed using the Aslamazov-Larkin theory. Near T c, a critical regime with a critical exponent of λ CR = 0.35 is effectively described by the E-model. © Springer Science+Business Media, LLC 2012.
Yakin M.,Ankara Nuclear Research And Training Center
Journal of Glaucoma | Year: 2016
PURPOSE:: To evaluate short-term to long-term outcomes of Ahmed glaucoma valve (AGV) implantation in the management of uveitic glaucoma (UG) secondary to Behçet disease (BD). PATIENTS AND METHODS:: A retrospective chart review of 47 eyes of 35 patients with UG secondary to BD who underwent AGV implantation was conducted. Success was defined as having an intraocular pressure (IOP) between 6 and 21 mm Hg with (qualified success) or without (complete success) antiglaucomatous medications and without need for further glaucoma surgery. RESULTS:: Mean postoperative follow-up was 57.72±26.13 months. Mean preoperative IOP was 35.40±8.33 mm Hg versus 12.28±2.90 mm Hg at the last follow-up visit (P<0.001). Mean number of preoperative topical antiglaucomatous medications was 2.96±0.29 versus 0.68±1.12 at the last follow-up visit (P<0.001). In all eyes, IOP could be maintained between 6 and 21 mm Hg with or without antiglaucomatous medications during follow-up. The cumulative probability of complete success was 46.8% at 6 months, 40.4% at 12 months, and 35.9% at 36 months, and the cumulative probability of eyes without complication was 53.2% at 6 months, 46.5% at 12 months, and 39.6% at 24 months postoperatively based on Kaplan-Meier survival analysis. No persistent or irreparable complications were observed. CONCLUSIONS:: This study includes one of the largest series of AGV implantation in the management of UG with the longest follow-up reported. AGV implantation can be considered as a primary surgical option in the management of UG secondary to BD with 100% total success rate (with or without medications). Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.