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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.


Sarikaya M.,Sinop University | Gullu A.,Gazi University
Journal of Cleaner Production | Year: 2014

In manufacturing industry, the effect of cutting fluids has been known on the health, environment and productivity at machining operations such as turning, milling, drilling, etc. Surface roughness is a common indicator of the quality characteristics for machining processes. The machining process is more complex, and therefore, it is very hard to determine the effects of process parameters on surface quality in all turning operations. In this study, design of experiments has been used to study the effect of the main turning parameters such as cooling condition, cutting speed, feed rate and depth of cut on arithmetic average roughness (Ra) and average maximum height of the profile (Rz) when turning of AISI 1050 steel. Experiments have been performed under dry cutting (DC), conventional wet cooling (CC) and MQL. Tests are designed according to Taguchi's L16 (43 × 21) orthogonal array. ANOVA analysis was performed to determine the importance of machining parameters on the Ra and Rz. The results were analyzed using 3D surface graphs, signal-to-noise ratios (S/N) and main effect graphs of means. Optimal operating parameters were determined using the S/N ratio and desirability function analysis. Mathematical models have been created for surface roughness, namely Ra and Rz, through response surface methodology (RSM). The results indicate that the most effective parameters are feed rate on the surface roughness. Cooling conditions are significantly effective on the surface roughness. MQL is a good tool in order to increase of the machined surface quality for cutting operations. © 2013 Elsevier Ltd. All rights reserved.


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.


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.


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.


Kosar B.,Sinop University | Albayrak C.,Sinop University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

In this work the electronic structure of (E)-4-methoxy-2-[(p-tolylimino) methyl]phenol has been characterized by the B3LYP/6-31G(d) level by using density functional theory. The experimental infrared and electronic absorption spectra have been obtained and compared with the theoretically obtained ones. Molecular electrostatic potential map has been evaluated; natural bond orbital and frontier molecular orbitals analysis have been performed from the optimized geometry. The energetic behavior of the title compound has been examined in solvent media using polarizable continuum model. The non-linear optical properties have been computed with the same level of theory. In addition, the changes of thermodynamic properties have been obtained in the range of 100-500 K. © 2010 Elsevier B.V. All rights reserved.


Yola M.L.,Sinop University | Eren T.,Dumlupinar University | Atar N.,Dumlupinar University
Sensors and Actuators, B: Chemical | Year: 2014

In this report, we developed surface plasmon resonance (SPR) sensor for the sensitive determination of amoxicillin (AMOX) in chicken egg and human plasma. Firstly, the modification of gold surface of SPR chip was performed by allyl mercaptane. Then, AMOX-imprinted poly(2-hydroxyethyl methacrylate- methacryloylamidoglutamic acid) [p(HEMAGA)] nanofilm was generated on the allyl mercaptane modified gold surface. The unmodified and imprinted surfaces were characterized by fourier transform infrared (FTIR) spectroscopy, ellipsometry and contact angle measurements. The developed method was validated according to the ICH guideline. The linearity range and the detection limit were obtained as 0.1-2.0 ng/mL and 0.022 ng/mL, respectively. The developed imprinted nanosensor was applied to the chicken egg and human plasma samples for the determination of AMOX. In addition, isotherm models were applied to data to explain adsorption process. © 2014 Elsevier B.V.


Yola M.L.,Sinop University | Atar N.,Dumlupinar University | Eren T.,Dumlupinar University
Sensors and Actuators, B: Chemical | Year: 2014

The molecular imprinting technique depends on the molecular recognition. It is polymerization method occuring around the target molecule. Thus this technique creates specific cavities in the cross-linked polymeric matrices. Amikacin (AMIK) is an important aminoglycoside (AG) antibiotic used to treat different types of bacterial infections. In this study, we prepared surface plasmon resonance (SPR) sensor for the determination of AMIK in human plasma. After the modification of gold surface of SPR chip was performed by allyl mercaptane, AMIK-imprinted poly(2-hydroxyethyl methacrylate- methacryloylamidoaspartic acid) [p(HEMA-MAAsp)] film was generated on the allyl mercaptane modified gold surface. The non-modified and imprinted surfaces were characterized by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and contact angle measurements. The developed method was validated according to the ICH guideline. The linearity range and the detection limit were obtained as 0.01-0.15 μg/mL and 0.0025 μg/mL (4.3 × 10-9 mol/L), respectively. The developed AMIK-imprinted nanosensor was successfully applied to the human plasma samples for the determination of AMIK. © 2014 Elsevier B.V. All rights reserved.


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.


The present study describes a new polychaete species belonging to the family Eunicidae, Marphysa cinari sp. nov., collected from the Sea of Marmara and the Aegean Sea (eastern Mediterranean), and re-describes Marphysa disjuncta Hartman, 1961 and Marphysa kinbergi McIntosh, 1910. The new species is mainly characterized by having unidentate subacicular hooks with a terminal hood and compound falciger chaetae on posterior parapodia. The shape of unidentate hooks of M. cinari is a very important character for distinguishing this species from other species. Atlantic species M. kinbergi and Pacific species M. disjuncta are very close species and the present paper deals with the differences and similarities between them and the new taxon.http://zoobank.org/urn:lsid:zoobank.org:pub:E8503032-81D3-4B4D-AAA0-9164E05E613F. © 2014 © 2014 Taylor & Francis.

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