Atatürk University

About: Atatürk University is a education organization based out in Erzurum, Turkey. It is known for research contribution in the topics: Population & Oxidative stress. The organization has 5710 authors who have published 14234 publications receiving 264334 citations. The organization is also known as: Atatürk Üniversitesi.

A Broadband and Stable Method for Unique Complex Permittivity Determination of Low-Loss Materials

Abstract: Transmission-reflection methods suffer from the increasing uncertainty in the phase of reflection scattering ( S-) parameter measurements of low-loss materials. In addition, transmission S -parameter measurements produce multiple solutions for the complex permittivity. In this paper, we propose a broadband and stable method for unique complex permittivity determination of low-loss materials by eliminating these problems. For elimination of the phase uncertainty problem, we utilize only the amplitudes of reflection S -parameters and complex transmission S-parameters. In order to avoid multiple solutions, we express multivalued terms, which result in multiple solutions, in terms of single-valued terms. The method can work very well in limited frequency-band applications or for dispersive materials since it is based on point-by-point (or frequency-by-frequency) extraction. We measured the complex permittivity of two low-loss dielectric materials by different methods for validation of the method.

Synthesis of 4,5-disubstituted-2-thioxo-1,2,3,4-tetrahydropyrimidines and investigation of their acetylcholinesterase, butyrylcholinesterase, carbonic anhydrase I/II inhibitory and antioxidant activities.

Abstract: A series of tetrahydropyrimidinethiones were synthesized from thiourea, β-diketones and aromatic aldehydes, such as p-tolualdehyde, p-anisaldehyde, o-tolualdehyde, salicylaldehyde and benzaldehyde. These cyclic thioureas showed good inhibitory action against acetylcholine esterase (AChE), butyrylcholine esterase (BChE), and human (h) carbonic anhydrase (CA) isoforms I and II. AChE and BChE inhibitions were in the range of 6.11-16.13 and 6.76-15.68 nM, respectively. hCA I and II were effectively inhibited by these compounds, with Ki values in the range of 47.40-76.06 nM for hCA I, and of 30.63-76.06 nM for hCA II, respectively. The antioxidant activity of the cyclic thioureas was investigated by using different in vitro antioxidant assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging, Cu2+ and Fe3+ reducing, and Fe2+ chelating activities.