Browsing by Author "Doğan M."

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Characterization, adsorption, and electrokinetic properties of modified sepiolite
(2016-09-01) Turan Beyli P.; Doğan M.; Alkan M.; Türkyılmaz A.; Turhan Y.; Demirbaş Ö.; Namli H.
The metal ion adsorption and electrokinetic properties of sepiolite modified by 3-(trimetoxysilyl)propyl metaacrylate was studied. The characterization of modified sepiolite was made by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron micrograph (SEM), and differential thermal analysis/thermogravimetry (DTA/TG). The adsorption behavior of Fe(III), Mn(II), Co(II), Zn(II), Cu(II), and Cd(II) metal ions on modified sepiolite from aqueous solutions was investigated as a function of equilibrium pH, temperature, and ionic strength. The adsorption experiments were carried out using a batch method. The initial and final concentrations of heavy metals were determined by means of atomic absorption spectrophotometry. The zeta potential of the modified sepiolite suspensions was measured as a function of metal ion concentration and equilibrium pH using a Zeta Meter 3.0. The results showed that the amount of adsorbed metal ions increased with solution pH, and that the modified sepiolite adsorbed Cu(II) and Mn(II) ions more than other metal ions. It was found that the temperature had an important effect on metal ion adsorption and that the adsorption process was endothermic in nature. Equilibrium isotherms for the adsorption of metal ions were measured experimentally. Results were analyzed by the Freundlich and Langmuir equations and determined the characteristic parameters for each adsorption isotherm. The isotherm data were reasonably well correlated by Langmuir isotherm. Maximum monolayer adsorption capacity of modified sepiolite for Cu(II), Mn(II), Zn(II), Fe(III), Co(II), and Cd(II) metal ions was calculated from 12.3 × 10−5, 11.7 × 10−5, 9.0 × 10−5, 8.2 × 10−5, 5.7 × 10−5, and 1.8 × 10−5 mol L−1, respectively. The affinity order of adsorption was Cu(II) > Mn(II) > Zn(II)–Fe(III) > Co(II) > Cd(II). The results indicate that modified sepiolite is good adsorbent for the removal of metal ions from aqueous solutions.
Determination of biological studies and molecular docking calculations of isatin-thiosemicarbazone hybrid compounds
(2022-09-15) Koçyiğit Ü.M.; Doğan M.; Muğlu H.; Taslimi P.; Tüzün B.; Yakan H.; Bal H.; Güzel E.; Gülçin İ.
Design, synthesis, structural elucidation, and investigation of cytotoxic and antimicrobial activity, butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) enzyme inhibition effects of isatin-thiosemicarbazone hybrid compounds (1–15) are reported in this study. Hybrid compounds (14 and 15) were synthesized, isolated, and characterized for the first time. FT-IR, 1H NMR, and 13C NMR spectroscopic methods and elemental analysis were used to characterize the structures of the compounds. In the enzymatic evaluation, hybrid compound 13 was observed as the most potent inhibitor of AChE with a Kİ value of 0.94 ± 0.13 µM (all compound Kİ values between 0.94 ± 0.13 and 4.47 ± 0.92), also this compound was observed as the most potent inhibitor of BChE with a Kİ value of 0.82 ± 0.11 µM (all compounds had Kİ values between of 0.82 ± 0.11 and 3.48 ± 0.92). Almost all compounds were shown better inhibition profile than standard compound. In the theoretical calculations, the comparison of the biological activities of isatin-thiosemicarbazone hybrid derivatives against enzymes was studied. The enzymes studied in docking calculations are AChE and BChE. Then, ADME/T analysis was conducted to examine the drug properties of these derivatives. Besides, the antimicrobial activity of these molecules was investigated by the microdilution method according to Clinical Laboratory Standards Institute (CLSI) criteria in the study. Cytotoxic activity of isatin-thiosemicarbazone hybrids was determined by the XTT cell viability assay on human breast cancer cell lines MCF-7 and MDA-MB-231. Among the hybrid compounds, compound 8 exhibited the most potent cytotoxic activity with IC50 values of 23.42 ± 0.21 µg/mL and 19.68 ± 0.23 µg/mL on MCF-7 and MDA-MB-231 cell lines, respectively. Overall, the hybridization of isatin and thiosemicarbazone skeleton has played an essential role in the inhibition of enzymes and cytotoxic activity.
Pollen morphology of the genus Lamium L. (Lamiaceae) and its systematic implications
(2016-01-01) Atalay Z.; Celep F.; Bilgili B.; Doğan M.
This is the first comprehensive palynological investigation of the genus Lamium. The pollen morphology of 48 taxa (including species, subspecies and varieties) of the genus Lamium was investigated and documented using light microscopy (LM) and scanning electron microscopy (SEM). Lamium pollen is small to medium sized (P = 21.65-39.96 μm), oblate-spheroidal to subprolate in shape and tricolpate. Three major exine sculpturing patterns (reticulate, granulate and microreticulate) were observed. The results indicated that the exine sculpturing pattern of Lamium is systematically informative at sectional level, but not at the species and infraspecific levels. In the present study, the palynological data are compared with available phylogenetic studies to evaluate the systematic value of pollen characters in the genus. Analysis show that; (1) Mennema's infrageneric classification is partly corroborated by our palynological data, (2) recent phylogenetic analysis on the genus and our results are partly corroborated, and (3) pollen morphology supports the inclusion of L. galeobdolon (=Galeobdolon), L. orientale and L. multifidum (=Wiedemannia) in Lamium. (4) Variation in exine sculpturing pattern have systematic importance particularly at sectional level.