Ahi Evran University

About: Ahi Evran University is a education organization based out in Kırşehir, Turkey. It is known for research contribution in the topics: Density functional theory & Ab initio. The organization has 842 authors who have published 2270 publications receiving 21904 citations.

Application of full factorial design for the preconcentration of chromium by solid phase extraction with Amberlyst 36 resin

Abstract: The preconcentration of chromium(III) by solid phase extraction and its determination from aqueous solutions by flame atomic absorption spectrometry (FAAS) is investigated by applying an experimental design. The optimization of the preconcentration variables such as pH of the sample solution, flow rate of the sample solution and concentration of elution solution was carried out using 23 full factorial design. The most important parameter affecting the preconcentration of chromium is the concentration of eluent. In the established experimental conditions, chromium can be determined with a relative standard deviation of 2.0% (N = 7) for a chromium concentration of 100 µg L−1. The detection limit for chromium was 1 µg L−1 (N = 20). The adsorption capacity of Amberlyst 36 is found to be 90.9 mg g−1 for chromium. Effect of other ions on the procedure was also evaluated. The method was validated by the analysis of certified reference materials (tea leaves GBW 07605 and fish tissue IAEA-407). The method was applied to the determination of chromium in waste water, dam water, carrot, parsley and lettuce.

Frequency effect on electrical and dielectric characteristics of In/Cu 2 ZnSnTe 4 /Si/Ag diode structure

Abstract: In/Cu2ZnSnTe4/Si/Ag diode structure was fabricated by sputtering Cu2ZnSnTe4 (CZTTe) thin film layer on the Si layer with In front contact. The frequency dependent room temperature capacitance and conductance measurements were carried out to obtain detailed information of its electrical characteristics. Admittance spectra of the diode exhibited strong frequency dependence and the obtained values showed decreasing behavior with the increase in the applied frequency. The effect of interfacial film layer with series resistance values and density of interface states were investigated by taking into consideration of non-ideal electrical characteristics of the diode. The distribution profile of the interface states was extracted by Hill-Coleman and high–low frequency capacitance methods. As a function of frequency, they were in proportionality with the inverse of applied frequency. Dielectric constant and dielectric loss parameters were calculated from the maximum value of the diode capacitance at the strong accumulation region. The loss tangent showed a characteristic peak behavior at each frequency. Based on the time-dependent response of the interfacial charges to the applied ac field, the values of ac electrical conductivity and complex electric modulus were calculated and discussed as a function of frequency and bias voltage.

Molecular Docking, Drug Likeness, and ADMET Analyses of Passiflora Compounds as P-Glycoprotein (P-gp) Inhibitor for the Treatment of Cancer

Abstract: Cancer disease leads to deaths worldwide. Anti-cancer drugs have a high prevalence of side effects and cause multidrug resistance (MDR) that remains a significant barrier to major cancer therapy. To date, chemical and herbal substances have been analyzed for their MDR modulatory activity. However, research on new and safe molecules has been continued to overcome MDR in cancer. The plant compounds can be an effective inhibitor for successful cancer therapy. Recently, computational models have gained importance to discover new inhibitors. In the present study, we aimed to explore the various compounds of Passiflora species as P-gp inhibitor. P-gp protein was docked with the active substrate and inhibitor, respectively, including tamoxifen and verapamil. Besides, 3D structure of P-gp was docked with 11 compounds (luteolin, beta amyrin, beta-sitosterol, chimaphilin, chrysin, edulan I and II, apigenin, oleanolic acid, stigmasterol, hydroxyflavone) of plant origin using AutoDock4.2 program. Furthermore, the compounds were analyzed for ADMET and drug likeness properties of compounds determined as Lipinski, Veber, and Ghose’s rules ( http://www.swissadme.ch/ ). As obtained molecular docking analysis results, luteolin, chrysin, hydroxyflavone, and apigenin may be a candidate for being P-gp inhibitor. Hence, it may be of attention to consider these compounds for further in vitro and in vivo evaluation.

Fosfomycin: In vitro efficacy against multidrug-resistant isolates beyond urinary isolates

Abstract: Objectives Fosfomycin (FOF) is a bactericidal antimicrobial agent active against a range of Gram-negative bacteria, including multidrug-resistant (MDR) and metallo-β-lactamase (MBL)-producing Enterobacteriaceae. However, data are scarce regarding use of the drug beyond urinary tract infections (UTIs). Methods In this study, susceptibility rates to FOF among 290 MDR Enterobacteriaceae isolates were analysed by gradient and disk diffusion tests and the results were compared with agar dilution according to the Clinical and Laboratory Standards Institute (CLSI). Minimum inhibitory concentrations (MICs) of imipenem (IPM) for isolates IPM-resistant/intermediate-susceptible isolates were determined by gradient test. In addition, the gradient test was used to determine MBL production. Results Of the 290 extended-spectrum β-lactamase (ESBL)-positive isolates, 60 (20.7%) were resistant to FOF, with rates of 9.5% for Escherichia coli, 28.0% for Enterobacter spp., 35.7% for Klebsiella spp. and 50.0% for Morganella spp. Among the 290 ESBL-positive isolates, 19 (6.6%) were resistant/intermediate-susceptible to IPM. In addition, 72.2% of extensively drug-resistant (XDR) and 61.1% of carbapenem-resistant isolates were resistant to FOF. In vitro FOF activity was higher among blood (86.9%) and genitourinary (91.7%) isolates. FOF showed excellent activity for a wide range of infections; however, further trials are necessary to evaluate its clinical efficacy. Conclusions FOF presented good activity even against carbapenem-resistant isolates and may be a treatment alternative for non-UTI isolates, but should be used with caution for infections related to ESBL-producing Klebsiella spp.