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Öğe The effect of Plantago major Linnaeus on serum total sialic acid, lipid-bound sialic acid, some trace elements and minerals after administration of 7,12-dimethylbenz(a)anthracene in rats(SAGE, 2012-04) Oto, Gökhan; Ekin, Suat; Özdemir, Hülya; Levent, Abdulkadir; Berber, İsmetThe present study was designed to evaluate the effect of Plantago major Linnaeus (PM) extract on serum total sialic acid (TSA), lipid-bound sialic acid (LSA), some trace elements (copper (Cu), zinc (Zn) and iron) and mineral levels (magnesium, calcium and sodium) in Wistar albino rat administrated 7,12-dimethylbenz(a)anthracene (DMBA). Rats were divided into three equal groups (n = 6). Group I comprised the control group, group II was treated with DMBA (100 mg/kg, single dose) and group III was treated with DMBA (100 mg/kg single dose) and aqueous extract of PM 100 mg/kg/day for 60 days. After 60 days, statistical analyses showed that TSA and LSA levels in DMBA and DMBA + PM groups were significantly higher compared to the control group (TSA: p < 0.01, p < 0.05; LSA: p < 0.05, p < 0.05, respectively). Serum Zn levels were decreased in subjects treated with DMBA (p < 0.01) and DMBA + PM (p < 0.05) compared to the control group values. Serum Cu levels were increased in DMBA group and PM-treated group compared to the control group values. The results of this investigation showed that the levels of TSA and LSA changed significantly, which are sensitive markers for detecting the toxic effects of DMBA. On the other hand, observed decline in Zn levels in rats from DMBA + PM group might be due to decreased generation of free radicals and oxidative stress. Results from this study suggest that PM may be partially effective in preventing carcinogenesis initiated by environmental carcinogen DMBA.Öğe Strength and failure analysis of inverse Z joints bonded with Vinylester Atlac 580 and Flexo Tix adhesives(Springer, 2012-11) Adin, Hamit; Turgut, AydınIn this study, the tensile strength and failure loads of the inverse Z joints were analyzed both experimentally and numerically by using two adhesives with different properties under a tensile load. Vinylester Atlac 580 and Flexo Tix were used as adhesives and the joints were prepared with two different composite materials. Initially, the mechanical properties of the adhesives were specified using bulk specimens. Then, the stress analyses were performed using three-dimensional finite element method (3-D FEM) via Ansys (V.10.0.1). The experimental results were compared with the numerical results and they were found quite reasonable. According to the test results, it can be seen that when the adherend thickness is increased, the stress increases as well. The most appropriate value of the adherend thickness is identified as t = 5 mm. Furthermore, it was observed that the lowest failure load was obtained at t = 3 mm the thickness for each specimen.Öğe Callus induction and plant regeneration from different explants of actinidia deliciosa(Springer Nature, 2008-10-31) Akbaş, Filiz; Işıkalan, Çiğdem; Namlı, SüreyyaIn this study, an efficient procedure was developed for callus induction and regeneration of kiwifruit (Actinidia deliciosa) using different organs of shoots developed under in vitro conditions. Effects of explants source and media (M1, 1.0 mg l-1 BA + 2.0 mg l-1 2,4-D-M 2, 1.0 mg l-1 NAA + 2.0 mg l-1 2,4-D) on initiation of callus were examined in order to obtain callus for organogenesis. The best callus for plant regeneration was obtained from leaf explants on Murashige and Skoog's medium (MS) supplemented with M2. Formation of callus from leaf of kiwifruit (A. deliciosa) was cultured in MS medium containing different concentration of N6-benzylaminopurin (BA; 0.0, 1.0, 2.0, 4.0, 6.0, 8.0 mg l-1) for callus proliferation and plant regeneration. Although the first shoot formation was appeared in medium containing 6.0 and 8.0 mg l-1 BA, the best shoots formation was obtained in medium with 4.0 mg l-1 BA.Öğe Assessment of natural radiation exposure levels and mass attenuation coefficients of lime and gypsum samples used in Turkey(Springer Nature, 2009-11-17) Damla, Nevzat; Çevik, Uğur; Kobya, Ali İhsan; Çelik, Ahmet; Çelik, NecatiThe activity concentrations of 226Ra, 232Th, and 40K in lime and gypsum samples used as building materials in Turkey were measured using gamma spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 38 ± 16, 20 ± 9, and 156 ± 54 Bq kg − 1 for lime and found to be 17 ± 6, 13 ± 5, and 429 ± 24 Bq kg − 1 for gypsum, respectively. The radiological hazards due to the natural radioactivity in the samples were inferred from calculations of radium equivalent activities (Raeq), indoor absorbed dose rate in the air, the annual effective dose, and gamma and alpha indices. These radiological parameters were evaluated and compared with the internationally recommended limits. The experimental mass attenuation coefficients (μ/ρ) of the samples were determined in the energy range 81–1,332 keV. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It is found that the calculated values and the experimental results are in good agreement.Öğe Electrical properties of safranine T p Si organic inorganic semiconductor devices(Cambridge University, 2010-04-25) Güllü, Ömer; Asubay, Sezai; Biber, Mehmet; Kılıçoğlu, Tahsin; Turut, AbdulmecitWe investigated the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of identically prepared safranine T/p-Si organic/inorganic Schottky devices (total 26 diodes) formed by evaporation of organic compound solution on p-Si semiconductor substrate. It was seen that the safranine T organic thin film on the p-Si substrate showed a good rectifying behavior. The barrier heights and ideality factors of all devices were extracted from the electrical characteristics. The mean barrier height and mean ideality factor from I-V measurements were calculated as 0.59±0.02 eV and 1.80±0.20, respectively. Also, the mean barrier height and mean acceptor doping concentration from C-V measurements were calculated as 0.67±0.10 eV and (6.96±0.37)×1014 cm-3, respectively. The discrepancy in the barrier height values obtained from I-V and C-V characteristics has been attributed to different nature of the measurements. The discrepancy between these values can also be due to the existence of the interfacial native oxide and the organic safranine T thin layer between the semiconductor substrate and top contact metal.Öğe On the energy distribution profile of interface states obtained by taking into account of series resistance in Al/TiO2/p–Si (MIS) structures(Elsevier, 2011-02-15) Pakma, Osman; Serin, Necmi; Serin, Saliha Tülay; Altındal, ŞemsettinThe energy distribution profile of the interface states (Nss) of Al/TiO2/pSi (MIS) structures prepared using the solgel method was obtained from the forward bias currentvoltage (IV) characteristics by taking into account both the bias dependence of the effective barrier height (φe) and series resistance (Rs) at room temperature. The main electrical parameters of the MIS structure such as ideality factor (n), zero-bias barrier height (φb0) and average series resistance values were found to be 1.69, 0.519 eV and 659 Ω, respectively. This high value of n was attributed to the presence of an interfacial insulator layer at the Al/pSi interface and the density of interface states (Nss) localized at the Si/TiO2 interface. The values of Nss localized at the Si/TiO2 interface were found with and without the Rs at 0.25-Ev in the range between 8.4×10 13 and 4.9×1013 eV-1 cm-2. In addition, the frequency dependence of capacitancevoltage (CV) and conductancevoltage (G/ω-V) characteristics of the structures have been investigated by taking into account the effect of Nss and R s at room temperature. It can be found out that the measured C and G/ω are strongly dependent on bias voltage and frequency.Öğe Experimental investigation of thermal performance in a concentric tube heat exchanger with wavy inner pipe(SpringerLink, 2012-06) Argunhan, Zeki; Çakmak, Gülşah; Yücel, Halit Lutfi; Yıldız, CengizIn this article, the heat transfer, friction factor, and thermal performance factor characteristics of a concentric-tube heat exchanger are examined experimentally. A wavy inner pipe is mounted in the tube with the purpose of generating swirl flow that would help to increase the heat transfer rate of the tube. The examination is performed for a Reynolds number ranging from 2700 to 8800. An empirical correlation is also formulated to match with experimental data of the Nusselt number using the Wilson plot method. In addition, to obtain the real benefits in using the swirl generator at a constant pumping power, the thermal enhancement factor is also determined. Over the range considered, the increases in the Nusselt number, friction factor, and thermal performance factor are found to be, respectively, about 113 %, 81 %, and 196 % higher than those obtained from a smooth-surface inner pipe.Öğe Synthesis, structural characterization of new macrocyclic Schiff base derived from 1,6-bis(2-formylphenyl)hexane and 2,6-diaminopyridine and its metal complexes(Scientific Publishers, 2008-04) İlhan, Salih; Sünkür, Murat; Temel, Hamdi; Teğin, İbrahimA macrocyclic ligand has been synthesized by reaction of 2,6-diaminopyridine and 1,6-bis(2-formylphenyl).hexane. Its complexes with Cu(II), Ni(II), Pb(II), Zn(II), Cd(II) and La(III) have been synthesized by the reaction of ligand and Cu(ClO4)(2)center dot 6H(2)O, Ni(ClO4)(2)center dot 6H(2)O, Pb(ClO4)(2)center dot 6H(2)O, Zn(ClO4)(2)center dot 6H(2)O, Cd(ClO4)(2)center dot 6H(2)O and La(ClO4)(3)center dot 6H(2)O, respectively. The ligand and its metal complexes have been characterized. All complexes are diamagnetic while the Cu(II) complex is binuclear.Öğe Synthesis of some novel pyrimidine derivatives and investigation of their electrochemical behavior(Wiley-Blackwell, 2010-12-20) Akbaş, Esvet; Levent, Abdulkadir; Gümüş, Selçuk; Sümer, Mehmet Rauf; Akyazı, İnci2-Iminopyrimidines (1a-e) and 2-thioxopyrimidine (2) were synthesized using the Biginelli three component cyclocondensation reaction of an appropriate β-diketone, arylaldehyde, and guanidine (for 1a-e) or thiourea (for 2). The electrochemical properties of the novel systems were investigated by CV and DPV. Moreover, B3LYP/6-31G(d,p) method was applied to the present structures in order to gather some structural and physicochemical data
