Zonguldak Karaelmas University

About: Zonguldak Karaelmas University is a based out in . It is known for research contribution in the topics: Population & Copolymer. The organization has 1939 authors who have published 4296 publications receiving 62466 citations.

Diffusion-weighted imaging in the head and neck region: usefulness of apparent diffusion coefficient values for characterization of lesions.

Abstract: PURPOSE We aimed to evaluate the role of apparent diffusion coefficient (ADC) values calculated from diffusion-weighted imaging for head and neck lesion characterization in daily routine, in comparison with histopathological results. METHODS Ninety consecutive patients who underwent magnetic resonance imaging (MRI) at a university hospital for diagnosis of neck lesions were included in this prospective study. Diffusion-weighted echo-planar MRI was performed on a 1.5 T unit with b factor of 0 and 1000 s/mm2 and ADC maps were generated. ADC values were measured for benign and malignant whole lesions seen in daily practice. RESULTS The median ADC value of the malignant tumors and benign lesions were 0.72×10-3 mm2/s, (range, 0.39-1.51×10-3 mm2/s) and 1.17×10-3 mm2/s, (range, 0.52-2.38×10-3 mm2/s), respectively, with a significant difference between them (P < 0.001). A cutoff ADC value of 0.98×10-3 mm2/s was used to distinguish between benign and malignant lesions, yielding 85.3% sensitivity and 78.6% specificity. The median ADC value of lymphomas (0.44×10-3 mm2/s; range, 0.39-0.58×10-3 mm2/s) was significantly smaller (P < 0.001) than that of squamous cell carcinomas (median ADC value 0.72×10-3 mm2/s; range, 0.65-1.06×10-3 mm2/s). There was no significant difference between median ADC values of inflammatory (1.13×10-3 mm2/s; range, 0.85-2.38×10-3 mm2/s) and noninflammatory benign lesions (1.26×10-3 mm2/s; range, 0.52-2.33×10-3 mm2/s). CONCLUSION Diffusion-weighted imaging and the ADC values can be used to differentiate and characterize benign and malignant head and neck lesions.

An Efficient Approximation to Numerical Solutions for the Kawahara Equation Via Modified Cubic B-Spline Differential Quadrature Method

Abstract: The main purpose of this work is to obtain the numerical solutions for the Kawahara equation via the Crank–Nicolson–Differential Quadrature Method based on modified cubic B-splines (MCBC-DQM). First, the Kawahara equation has been discretized using Crank–Nicolson scheme. Then, Rubin and Graves linearization technique has been utilized and differential quadrature method has been applied to obtain algebraic equation system. Four different test problems, namely single solitary wave, interaction of two solitary waves, interaction of three solitary waves, and wave generation, have been solved. Next, to be able to test the efficiency and accuracy of the newly applied method, the error norms $$ L _{2}$$ and $$ L _{\infty }$$ as well as the three lowest invariants $$ I _{1}$$ , $$ I _{2}$$ , and $$ I _{3}$$ have been computed. Besides those, the relative changes of invariants have been reported. Finally, the newly obtained numerical results have been compared with some of those available in the literature for similar parameters. The comparison of present results with earlier works showed that the newly method may be provide significant benefit in case of numerical solutions of the other nonlinear differential equations.

The use of porphyrins in potentiometric sensors as ionophores

Abstract: Porphyrins are a group of macrocyclic compounds which are widely used in many applications in the literature due to their multiple functions. One of their application areas is in the development of sensors which transform changes in physical and chemical parameters into electrical signals. Novel chemical sensors selective and sensitive for many anions and cations have been fabricated with the advancements in the technology. Real sample applications of these sensors can be successfully performed. In recent years, potentiometric methods have drawn researchers' attention and they have been highly studied because of their superiority over other analytical devices. Ionophores which are used in the development of potentiometric sensors and ion-selective electrodes are the most important components of these systems. Therefore, porphyrin molecules, which have favorable chemical structures, can be directly used as an active component (ionophore) in the structure of potentiometric sensors. In this review, we investigated porphyrin derivatives used as ionophore in the design of potentiometric sensors and we focused on newly developed potentiometric sensors based on porphyrin.