Browsing by Author "Özdemir S."
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Item Dietary vitamin e (α-tocopherol acetate) and selenium supplementation from different sources: Performance, ascites-related variables and antioxidant status in broilers reared at low and optimum temperatures(2007) Özkan S.; Malayoǧlu H.B.; Yalçin S.; Karadaş F.; Koçtürk S.; Çabuk M.; Oktay G.; Özdemir S.; Özdemir E.; Ergül M.1. This study compared the effect of dietary supplementation with organic or inorganic selenium (Se) sources plus control amounts or large amounts of vitamin E (-tocopherol acetate) in broilers raised at control (20 to 24C) or low (145 to 168C) temperatures after 2 weeks of age. 2. The following dietary treatments were used from one day old. Diet 1, the control diet, comprised a commercial diet containing 015 mg/kg inorganic Se and 50 mg vitamin E/kg feed. Diet 2 was the same as diet 1, supplemented with 015 mg/kg inorganic Se. Diet 3 was the same as diet 2 but was supplemented with 200 mg/kg vitamin E. Diet 4 was the same as diet 1, but inorganic Se was replaced with 030 mg/kg organic Se. Diet 5 was the same as diet 4, supplemented with 200 mg/kg vitamin E. 3. Low temperature reduced the growth rate of broilers; however, at 6 weeks, there were no differences in the body weights of birds fed on organic Se supplemented diets housed at low or control temperature. The feed conversion ratio was significantly affected by low temperature but not by diet. The heterophil/lymphocyte ratio was higher in chicks after one week in the cold, indicating mild stress. Blood triiodothyronine levels were significantly higher in birds after 1 and 4 weeks in the cold but thyroxin was not affected. 4. Organic Se supplementation increased relative lung weight at the control temperature, which might lead to greater respiratory capacity. Relative spleen weight significantly decreased in broilers fed diets supplemented with inorganic Se under cold conditions, a possible indication of chronic oxidative stress. 5. At the low temperature, supplementation with organic Se alone, or with inorganic Se and vitamin E increased glutathione peroxidase (GSHPx) activity and glutathione (GSH) concentration in the liver of broilers, which may indicate increased activity of birds' antioxidant defence against suboptimal environments.Item Plasma selenium levels in celiac disease patients on a gluten -free diet; [Glutensiz diyet alan çölyak hastası çocuklarda serum selenyum düzeyleri](Galenos Yayincilik,, 2012) Ünal F.; Umman C.; Tok A.C.; Semizel E.; Ecevit C.O.; Özdemir S.; Taneli F.; Kasirga E.Introduction: Celiac disease (CD) is a gluten-induced enteropathy that results in malabsorption of nutrients such as selenium. A high incidence of malignancy in CD has been previously reported. Selenium is known to have a protective role against cancer. This study aimed to investigate whether there is an effect on serum selenium levels in children with CD on a gluten-free diet. Materials and Methods: Serum levels of selenium were studied in 17 children (mean age 5.64±3.30 years) with CD and 20 age-and gender-matched healthy children. CD was diagnosed according to ESPGHAN criteria. All the patients were clinically well and had been on gluten-free diets for 11.11±1.98 (mean±SE) months. All patients were fully consistent with the diet. The concentration of selenium was determined by a periodically validated atomic absorption spectrometer (Perkin Elmer AAS 700 system). Wet ashing procedure was used for all samples and controls. Results: In CD group one child's (5.8%), and in control group three children's (%15) serum selenium levels were found under normal limits. There was no statistically significant difference between serum selenium levels and the duration of gluten free diet (p>0.05). There was no statistically significant difference in serum selenium levels between celiac patients (124.19±12.31 μg/L) and control group (92.47±12.06 μg/L), (p>0.05). Discussion: It can be concluded that, normal levels of serum selenium in children with CD can be achieved with fully compatible gluten-free diet and a balanced diet which supplies daily selenium requirement. © The Journal of Current Pediatrics, published by Galenos Publishing.Item Double split cord malformations in a child: Types I and II at 2 different levels in the same route: Report of a rare case(Lippincott Williams and Wilkins, 2015) Barutçuoʇlu M.; Umur A.S.; Özdemir S.; Mete M.; Selçuki M.Spinal split cord malformations (SSCMs) are thought to be originated from an error that causes splitting of the notochord during gastrulation period, in which the formation of an accessory neurenteric canal between the yolk sac and amnion cavity takes place. Herein, we reported a 1-month-old boy who had both type II SSCM with meningocele at Th2-4 level and type I SSCM at Th10-12 level. Between those 2 malformations there was a normally developed spinal cord. Lesions were surgically corrected with good cosmetic and neurological outcome. There have been divergent suggestions on these pathologies. Although the multisite closure model of the neural tube may be used for explanation of these multiple neural tube defects, this theory alone cannot explain the nature and mechanism of development of such developmental defects of the neural tube. The aim of this study is to understand the embryological changes that cause the formation of a composite split spinal cord malformation. The idea of temporally different unexpected events that may cause developmental defects at different levels while other segments continue to neurulate normally seems appropriate to explain the multiple midline closure defects. Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved.Item Harmonic estimation based support vector machine for typical power systems(Institute of Computer Science, 2016) Özdemir S.; Demirtaş M.; Aydin S.The power quality in electrical energy systems is very important and harmonic is the vital criterion. Traditionally Fast Fourier Transform (FFT) and Discrete Fourier Transform (DFT) have been used for the harmonic distortion analysis and in the literature harmonic estimations have been made using di erent methods. As an alternative method, this paper suggested using Support Vector Machine (SVM) for harmonic estimation. The real power energy distribution system has been examined and the estimation results have been compared with measured real data. The proposed solution approach was comparatively evaluated with the ANN and LR estimation methods. Comparison results show that THD estimation values that were obtained by the SVM method are close to the THD estimation values obtained from ANN (Artificial Neural Network) and LR (Linear regression) methods. The numerical results clearly showed that the SVM method is valid for THD estimation in the power system. © 2016 CTU FTS.Item Half bridge LLC resonance converter reliability analysis for OLED TVs; [OLED TV için yarim köprü LLC rezonans dönüştürücü güvenilirlik analizi](Gazi Universitesi Muhendislik-Mimarlik, 2019) Nil M.; Öztürk Y.; Özdemir S.; Sözen H.; Nil M.In this study, half-bridge LLC resonant DC-DC converter design was realized for 65 "AMOLED TV. The main objective of the design is to achieve the optimum level of reliability and to reach the appropriate life cycle of MTBF (Mean-time between failure). Reliability tests were carried out which cover the thermal, electromagnetic compatibility (EMC) and electrical tests of the designed power board and critical circuit components of this power board. Moreover, in order to analyze the operating characteristics of the circuit at different switching frequencies, simulation analyses were carried out by PSIM Program. As a result of the, all these simulations and empirical studies, a high level of reliability conditions have been achieved with a 120.215 hours MTBF value. © 2019 Gazi Universitesi Muhendislik-Mimarlik. All rights reserved.