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Sinop, Turkey

The molecular imprinting technique depends on the molecular recognition. It is a polymerization method around the target molecule. Hence, this technique creates specific cavities in the cross-linked polymeric matrices. In present study, a sensitive imprinted electrochemical biosensor based on Fe@Au nanoparticles (Fe@AuNPs) involved in 2-aminoethanethiol (2-AET) functionalized multi-walled carbon nanotubes (f-MWCNs) modified glassy carbon (GC) electrode was developed for determination of cefexime (CEF). The results of X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy (RAIRS) confirmed the formation of the developed surfaces. CEF imprinted film was constructed by cyclic voltammetry (CV) for 9 cycles in the presence of 80mM pyrrole in phosphate buffer solution (pH 6.0) containing 20mM CEF. The developed electrochemical biosensor was validated according to the International Conference on Harmonisation (ICH) guideline and found to be linear, sensitive, selective, precise and accurate. The linearity range and the detection limit were obtained as 1.0×10-10-1.0×10-8M and 2.2×10-11M, respectively. The developed CEF imprinted sensor was successfully applied to real samples such as human plasma. In addition, the stability and reproducibility of the prepared molecular imprinted electrode were investigated. The excellent long-term stability and reproducibility of the prepared CEF imprinted electrodes make them attractive in electrochemical sensors. © 2014 Elsevier B.V.

Carbon nanotubes are expected to play a significant role in the design and manufacture of many nano-material devices in the future. Carbon nanotubes exhibit many unique properties which generate strong interests in studying their applications. In addition, certain properties of gold nanoparticles (e.g., conductivity, catalytic and photocatalytic activity) suggest that gold-nanoparticle-functionalized carbon nanotubes may prove applicable in future fabrication of nanodevices. In this study, gold nanoparticles (AuNPs) with the mean diameters of 20-25 nm were self-assembled onto the surfaces of p-aminothiophenol functionalized multi-walled carbon nanotubes (p-MWCNs) sheets. The p-MWCNs and AuNPs/p-MWCNs nanocomposites were characterized by reflection-absorption infrared spectroscopy (RAIRS), transmission electron microscope (TEM), x-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and x-ray diffraction (XRD) method. The simultaneous determination of quercetin (QR) and rutin (RT) was performed by square wave voltammetry (SWV) on glassy carbon electrode (GCE) modified with AuNPs/p-MWCNs nanocomposite (AuNPs/p-MWCNs-GCE). QR presented two oxidation steps at Ea1 of 270 mV and Ea2 of 450 mV and RT presented only one oxidation step at Ea of 360 mV at AuNPs/p-MWCNs-GCE. The linearity ranges and the detection limits of QR and RT were 1.0 × 10 -9 - 5.0 × 10-8 M and 3.3 × 10-10. The application of the prepared nanocomposite to the analysis of real sample was also investigated. © 2013 Elsevier Ltd.

Balki M.K.,Sinop University | Sayin C.,Marmara University | Canakci M.,Kocaeli University
Fuel | Year: 2014

In this experimental study, the effect of alcohol (ethanol and methanol) use on the performance, emissions and combustion characteristics of a low power single-cylinder engine described the rated power output of the engine e.g. 2 kW were investigated and the results were compared with conventional gasoline operation. The tests were performed at full-throttle valve opening and variable engine speeds. The results show that the use of alcohol fuels increased the engine torque, brake specific fuel consumption (BSFC), thermal efficiency and combustion efficiency. In addition, the cylinder gas pressure and heat release rate occurred earlier; carbon dioxide (CO2) emission increased while hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxides (NOx) emissions decreased. © 2012 Elsevier Ltd. All rights reserved.

Yola M.L.,Sinop University | Eren T.,Dumlupinar University | Atar N.,Dumlupinar University
Electrochimica Acta | Year: 2014

A novel and sensitive electrochemical biosensor for selective determination of DNA was developed based on Fe@Au nanoparticles (Fe@AuNPs) involving 2-aminoethanethiol (AET) functionalized graphene oxide (GO) (Fe@AuNPs-AETGO). Firstly, 5′-TA CCG GGT GCT CGA GCT-(CH2)3-SH- 3′ single-stranded probe (ss-DNA) was immobilized on Fe@AuNPs-AETGO nanocomposite to form ssDNA-Fe@AuNPs-AETGO. Square wave voltammetry (SWV) was applied to monitor the DNA hybridization by basic blue 41 (BB41) as an electrochemical indicator. The DNA immobilization and hybridization on the film were studied by cyclic voltammetry (CV), SWV and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the peak currents of BB41 were linear with the logarithm of the concentrations of complementary DNA (5′-AT GGC CCA CGA GCT CGA-(CH2)3-SH-3) from 1.0 × 10-14 to 1.0 × 10-8 M with a detection limit of 2.0 × 10-15 M. The biosensor also showed high selectivity to one-base, two-base and three-base mismatched DNA. Compared with the other electrochemical DNA biosensors, the proposed biosensor showed its own performance of simplicity, good stability and high sensitivity. © 2014 Elsevier Ltd.

Duldul M.,Sinop University
Computer Aided Geometric Design | Year: 2010

In this paper, the method for computing the Frenet vectors and the curvatures of the transversal intersection curve of three parametric hypersurfaces is given in four-dimensional Euclidean space. © 2009 Elsevier B.V. All rights reserved.

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