Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 7Citation - Scopus: 7Synthesis and Characterization of Single-Walled Carbon Nanotube: Cyto-Genotoxicity in Allium Cepa Root Tips and Molecular Docking Studies(Wiley, 2022) İnce Yardımcı, Atike; İstifli, Erman Salih; Açıkbaş, Yaser; Liman, Recep; Yağmurcukardeş, Nesli; Yılmaz, Selahattin; Ciğerci, İbrahim HakkıHerein, single-walled carbon nanotubes (SWCNTs) were synthesized by the thermal chemical vapor deposition (CVD) method, and characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Raman spectroscopy, dynamic light scattering (DLS), and thermo-gravimetric analysis (TGA). The results indicated that obtained nanotubes were SWCNTs with high crystallinity and their average diameter was 10.15 ± 3 nm. Allium cepa ana–telophase and comet assays on the root meristem were employed to evaluate the cytotoxic and genotoxic effects of SWCNTs by examining mitotic phases, mitotic index (MI), chromosomal aberrations (CAs), and DNA damage. A. cepa root tip cells were exposed to SWCNTs at concentrations of 12.5, 25, 50, and 100 μg/ml for 4 h. Distilled water and methyl methanesulfonate (MMS, 10 μg/ml) were used as the negative and positive control groups, respectively. It was observed that MIs decreased statistically significantly for all applied doses. Besides, CAs such as chromosome laggards, disturbed anaphase–telophase, stickiness and bridges and also DNA damage increased in the presence of SWCNTs in a concentration-dependent manner. In the molecular docking study, the SWCNT were found to be a strong DNA major groove binder showing an energetically very favorable binding free energy of −21.27 kcal/mol. Furthermore, the SWCNT interacted effectively with the nucleotides on both strands of DNA primarily via hydrophobic π and electrostatic interactions. As a result, cytotoxic and genotoxic effects of SWCNTs in A. cepa root meristematic cells which is a reliable system for assessment of nanoparticle toxicology were demonstrated in this study.Article Citation - WoS: 21Citation - Scopus: 21Graphene-Supported Lafeo3 for Photocatalytic Hydrogen Energy Production(Wiley, 2021) Orak, Ceren; Yüksel, AslıHydrogen is a green, environmentally benign and sustainable energy source with no harmful combustion products to fulfil the increasing energy demand. Photocatalytic oxidation has various advantageous to produce hydrogen from different sources such as wastewater, alcohol solutions using different types of catalysts. Sucrose solution was chosen as a model solution to evolve hydrogen using LFO and GLFO catalysts under solar light irradiation, and graphene was used as a catalyst support to enhance the amount of produced hydrogen amount. A characterization study, which consists of SEM-EDX, BET, XRD, PL, TEM, XPS and FT-IR analyses, was carried out. A full factorial design was created via Minitab 18 to analyse the factors affecting the produced hydrogen amount, which are pH, catalyst loading, H2O2 concentration and graphene content statistically. Based on the results, graphene content is an important parameter and pH and H2O2 concentration have a synergetic effect over hydrogen production. Additionally, the effects of calcination temperature, pH, H2O2 concentration and catalyst loading over produced gases were investigated. The best promising result was obtained as 3388 mu mol/g(cat) at the following reaction conditions: 7.5 of pH, 0.1 g L-1 catalyst loading (GLFO, which is calcined at 700 degrees C) and using 15 mM H2O2 under solar light irradiation. Novelty Statement Hydrogen is produced from sucrose solution with low cost process requiring no special equipment, high pressure or temperature. First study that uses perovskite catalysts for the production of hydrogen from sucrose solution by photo-Fenton like oxidation GLFO is a promising photocatalyst for H-2 production by solar-Fenton like oxidation with the highest H-2 evaluation at 3388.34 mu mol/g(cat).Conference Object Investigation of Antimicrobial Activity To Determine Mic Value of Cinnamon Bark Oil Against Helicobacter Pylori(Wiley, 2014) Güneş, Seda; Becerikli, T.; Tıhmınlıoğlu, Funda; Yılmaz, Özlem[No abstract available]Conference Object In Vitro Evaluation of Bioactive Chitosan Microspheres for Eradicating Helicobacter Pylori Biofilm(Wiley, 2016) Güneş, Seda; Arslan, Nur; Demiray Gürbüz, Ebru; Tıhmınlıoğlu, Funda; Yılmaz, ÖzlemCertain H. pylori strains can form biofilm both inside and outside human host to protect itself under environmental stress. Biofilm contributes to development of antimicrobial resistance by some kind of mechanisms like providing a barrier for diffusion and allowing resistance gene expression.Conference Object Determination of Biofilm Formation by Helicobacter Pylori(Wiley, 2016) Arslan, Nur; Güneş, Seda; Demiray Gürbüz, Ebru; Tıhmınlıoğlu, Funda; Yılmaz, ÖzlemBackground : Certain H. pylori strains form biofilm in laboratory experiments and also on the surface of gastric mucosa, suggesting possible reason for eradication failure by increasing resistance to antimicrobial agents and transmission. Aim : To examine the mature biofilm formation by H. pylori NCTC11637 standard strain in different incubation periods for H. pylori biofilm characterization.