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Öğe ANTIMICROBIAL ACTIVITY OF COLLOIDAL SILVER NANOPARTICLES PREPARED BY SOL-GEL METHOD(Inst Materials Physics, 2011) Lkhagvajav, N.; Yasa, I.; Celik, E.; Koizhaiganova, M.; Sari, O.In this study, the antimicrobial activity of colloidal silver nanoparticles prepared by the sol-gel method was investigated, and the turbidity, viscosity and pH of the colloidal solutions were determined. The size of the silver nanoparticles was measured by Atomic Force Microscopy (AFM). The minimum inhibitory concentration (MIC) value of the colloidal solution resistance to test microorganisms Escherichia coli, Staphylococcus aureus, Candida albicans, Bacillus subtilis, Salmonella typhimurium, Pseudomonas aeruginosa and Klebsiella pneumoniae was carried out by the Broth Microdilution Method. It was found that the silver nanoparticles inhibited the growth and multiplication of the tested microorganisms, including the fungus C. albicans. The antimicrobial activity was observed against all tested microorganisms at a very low concentration of 2-4 mu g/ml of nano silver.Öğe Antimicrobial Nano-Ag-TiO2 Coating for Lining Leather(Ars Docendi, 2016) Kaygusuz, M. (Koizhaiganova); Lkhagvajav, N.; Yasa, I.; Celik, E.In this study, the characterization and the antimicrobial properties of nanosized Ag-TiO2 coatings on leather were investigated. For this purpose, turbidity, viscosity and pH of nAg-TiO2 solutions prepared by the sol-gel method were measured. The surface morphology of treated leathers was observed using Scanning Electron Microscopy (SEM) and the elemental analysis was performed by energy dispersive spectrometer (EDS). The antimicrobial performance of nAg-TiO2 coatings on leather materials to the test microorganisms as Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillius niger was evaluated by the application of qualitative (Agar overlay method) and quantitative (percentage of microbial reduction) tests. According to qualitative test results it was found that 2% and higher concentrations of nAg-TiO2 on the leather samples were effective against all microorganisms tested. Moreover, quantitative test results showed that leather samples treated with 5% of nAg-TiO2 demonstrated the highest antibacterial activity against E. coli with 93.50% bacterium removal, whereas 2% of nAg-TiO2 on leather was enough to exhibit the excellent percentage reduction against S. aureus of 99.99%. The results are promising for the use of colloidal nano Ag-TiO2 solution on lining leather as antimicrobial coating.Öğe Cerium-Doped Yttrium Iron Garnet Thin Films Prepared by Sol-Gel Process: Synthesis, Characterization, and Magnetic Properties(Springer-Verlag Berlin, 2009) Oeztuerk, Y.; Avgin, I.; Erol, M.; Celik, E.; Aktas, B; Mikailov, FWe studied here synthesis, characterization, and magnetic properties of YIG (yttrium-iron-garnet, Y3Fe5O12) and Ce-doped YIG (CexY3-xFe5O12) thin films prepared by using a sol-gel technique for magneto-optical applications. Pure YIG and Ce-doped YIG films were deposited on a glass and Si (100) substrates out of a solution prepared from Ce, Y, and Fe-based precursors, solvent, and chelating agent at low temperature using the sol-gel technique. Prior to coating process, solution characteristics that influence the intended thin film structure were determined using turbidimeter, pH meter, and rheometer machines. Film thickness was monitored with varying sol-gel solution's properties and spin coating's process parameters. Since we mainly want to improve the magnetic properties of our films, an optimum sol-gel solution containing cerium, yttrium, and iron precursors were found, and a garnet phase was formed after annealing at temperatures between 700 and 1,000 degrees C for 2 h in air. The thermal, structural, and microstructural properties of the films were characterized using DTA/TG, XRD, and SEM-EDS. The magnetic properties of the films produced by doping with Ce with an optimal process conditions were investigated through VSM device. The films include micro and nanosize CeO2 regions because of using partially dissolved Ce precursor in the solution. Our preliminary study revealed that a significant improvement in magnetic properties of polycrystalline YIG thin films have been achieved through the substitution of Ce.Öğe Characterization and antimicrobial performance of nano silver coatings on leather materials(Springer, 2015) Lkhagvajav, N.; Koizhaiganova, M.; Yasa, I.; Celik, E.; Sari, O.In this study, the characterization and the antimicrobial properties of nano silver (nAg) coating on leather were investigated. For this purpose, turbidity, viscosity and pH of nAg solutions prepared by the sol-gel method were measured. The formation of films from these solutions was characterized according to temperature by Differential Thermal Analysis-Thermogravimetry (DTA-TG) equipment. The surface morphology of treated leathers was observed using Scanning Electron Microscopy (SEM). The antimicrobial performance of nAg coatings on leather materials to the test microorganisms as Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillius niger was evaluated by the application of qualitative (Agar overlay method) and quantitative (percentage of microbial reduction) tests. According to qualitative test results it was found that 20 mu g/cm(2) and higher concentrations of nAg on the leather samples were effective against all microorganisms tested. Moreover, quantitative test results showed that leather samples treated with 20 mu g/cm(2) of nAg demonstrated the highest antibacterial activity against E. coli with 99.25% bacterium removal, whereas a 10 mu g/cm(2) concentration of nAg on leather was enough to exhibit the excellent percentage reduction against S. aureus of 99.91%. The results are promising for the use of colloidal nano silver solution on lining leather as antimicrobial coating.Öğe Characterization and antimicrobial performance of nano silver coatings on leather materials(Springer, 2015) Lkhagvajav, N.; Koizhaiganova, M.; Yasa, I.; Celik, E.; Sari, O.In this study, the characterization and the antimicrobial properties of nano silver (nAg) coating on leather were investigated. For this purpose, turbidity, viscosity and pH of nAg solutions prepared by the sol-gel method were measured. The formation of films from these solutions was characterized according to temperature by Differential Thermal Analysis-Thermogravimetry (DTA-TG) equipment. The surface morphology of treated leathers was observed using Scanning Electron Microscopy (SEM). The antimicrobial performance of nAg coatings on leather materials to the test microorganisms as Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillius niger was evaluated by the application of qualitative (Agar overlay method) and quantitative (percentage of microbial reduction) tests. According to qualitative test results it was found that 20 mu g/cm(2) and higher concentrations of nAg on the leather samples were effective against all microorganisms tested. Moreover, quantitative test results showed that leather samples treated with 20 mu g/cm(2) of nAg demonstrated the highest antibacterial activity against E. coli with 99.25% bacterium removal, whereas a 10 mu g/cm(2) concentration of nAg on leather was enough to exhibit the excellent percentage reduction against S. aureus of 99.91%. The results are promising for the use of colloidal nano silver solution on lining leather as antimicrobial coating.Öğe Characterization and antimicrobial performance of nano silver coatings on leather materials(Springer, 2015) Lkhagvajav, N.; Koizhaiganova, M.; Yasa, I.; Celik, E.; Sari, O.In this study, the characterization and the antimicrobial properties of nano silver (nAg) coating on leather were investigated. For this purpose, turbidity, viscosity and pH of nAg solutions prepared by the sol-gel method were measured. The formation of films from these solutions was characterized according to temperature by Differential Thermal Analysis-Thermogravimetry (DTA-TG) equipment. The surface morphology of treated leathers was observed using Scanning Electron Microscopy (SEM). The antimicrobial performance of nAg coatings on leather materials to the test microorganisms as Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillius niger was evaluated by the application of qualitative (Agar overlay method) and quantitative (percentage of microbial reduction) tests. According to qualitative test results it was found that 20 mu g/cm(2) and higher concentrations of nAg on the leather samples were effective against all microorganisms tested. Moreover, quantitative test results showed that leather samples treated with 20 mu g/cm(2) of nAg demonstrated the highest antibacterial activity against E. coli with 99.25% bacterium removal, whereas a 10 mu g/cm(2) concentration of nAg on leather was enough to exhibit the excellent percentage reduction against S. aureus of 99.91%. The results are promising for the use of colloidal nano silver solution on lining leather as antimicrobial coating.Öğe Effect of pH and annealing temperature on the structural and magnetic properties of cerium-substituted yttrium iron garnet powders produced by the sol-gel method(De Gruyter Poland Sp Zoo, 2016) Yarici, I.; Erol, M.; Celik, E.; Ozturk, Y.Cerium substituted yttrium iron garnet (Ce0.2Y2.8Fe5O12; Ce-YIG) nanoparticles were produced via the sol-gel method from solutions of Ce-, Y- and Fe-based precursors, a solvent and a chelating agent. The solutions were dried at 200 degrees C and heat treated at temperatures between 800 degrees C and 1400 degrees C for 3 h in air. The effects of pH and annealing temperature on the structure, phase formation, magnetic properties and crystallite size were investigated. A cubic YIG phase was obtained for the sample annealed at 1400 degrees C. The presented results showed that the pH value of the starting solution affects the crystal size and consequently, the saturation magnetization.Öğe Fabrication and Characterization of Gd2O2SO4:Tb3+ Phosphors by Sol-gel Method(Amer Inst Physics, 2017) Aritman, I.; Yildirim, S.; Kisa, A.; Guleryuz, L. F.; Yurddaskal, M.; Dikici, T.; Celik, E.; Oral, AY; Oral, ZBB; Sezer, M; Kol, S; Akoz, METhe objective of the innovative approaches of the scintillation materials to be used in the digital portal imaging systems in the radiotherapy applications is to research the GOS material production that has been activated with the rare earth elements (RE), to produce the scintillation detectors that have a rapid imaging process with a lesser radiation and higher image quality from these materials and to apply the radiographic imaging systems. The GOS: Tb3+ showed high emission peak and high x-ray absorption properties which have been determined for application to mammography and dental radiography. In this study, Gd2O2SO4: Tb3+ phosphors were fabricated by the sol-gel method that is a unique technique and not previously applied. Besides, the structural characterization of GOS: Tb3+ has been investigated. The strongest emission peak located at 549 nm under 312 nm UV light excitation was appeared on the GOS: Tb3+ phosphor particles. The characterization processing optimized by using FTIR, DTA-TG, XRD, XPS, SEM and the luminescence spectroscopy.Öğe Production and Characterization of Magnetic and Luminescent Gd2O2SO4:Eu3+ Nanoparticles by Sol-gel Technique(Amer Inst Physics, 2017) Aritman, I.; Yildirim, S.; Kisa, A.; Guleryuz, L. F.; Yurddaskal, M.; Dikici, T.; Celik, E.; Oral, AY; Oral, ZBB; Sezer, M; Kol, S; Akoz, MERadiographic imaging which transforms y or x rays into visible light is one of the most important developments in the field of digital imaging systems in recent years. Materials consisting of rare earth elements have strong scintillation properties in digital radiology. Gd2O2SO4 is studied due to having effective magnetic properties and excellent luminescence spectra. Additionally, Gd2O2SO4: Eu3+ has thermal stability and ideal red light emission performance with peak emission at around 618 nm when activated under X-ray or ultraviolet light. In this study, Gd2O2SO4: Eu3+ nanoparticles were synthesized by sol-gel method and were calcined at 950 degrees C in argon gas atmosphere. In the analysis of the produced nanoparticles XRD, SEM, XPS and optical luminescence devices were used to evaluate the results.Öğe PRODUCTION AND DEVELOPMENT OF MONOCLINIC YTTRIUM TANTALATE (M '-YTaO4) X-RAY PHOSPHOR VIA SOL-GEL TECHNIQUE(Technical Univ Cluj-Napoca, 2014) Yildirim, S.; Demirci, S.; Mermer, O.; Toparli, M.; Alicikus, L. Zumre Alican; Akman, F.; Celik, E.; Popescu, DMonoclinic yttrium tantalate (M'-YTaO4) are efficient X-ray phosphor used in X-ray medical imaging, in which these phosphor are used in films/screen cassettes, and also in electronic detector systems such as computed radiography, computed tomography and fluoroscopy. Performances of these phosphor are related to composition, crystalline structure, surface properties and luminescence properties of films. In this study, M'-YTaO4 films were synthesized by five steps sol-gel spin coating route on single crystal silicon substrate. And then these films were dried at 120 degrees C and were sintered at 1200 degrees C for 4 hours and slowly cooled to room temperature. The obtained films were characterized by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and differential thermal analysis (DTA). After sintering, monoclinic M'-YTaO4 phase was obtained.Öğe Production, characterization and magnetic properties of Bismuth-substituted Yttrium Iron Garnet layers prepared by sol-gel process(Iop Publishing Ltd, 2009) Erol, M.; Ozturk, Y.; Avgin, I.; Celik, E.; Gencer, A; Grasso, GIn this study, (BiY2)Fe5O12 (Bi:YIG) magneto-optic layers were deposited on Si(100) and glass substrates using a sol-gel process. Bi, Y and Fe based-precursors were dissolved using methanol and glacial asetic acid as a solvent and chelating agent respectively. The turbidity, viscosity, gel point and pH values of the prepared solutions were determined using turbidimeter, rheometer and pHmeter. The prepared xerogels were dried and used for DTA/TG analysis to determine heat treatment regime in thin film production. Based on DTA/TG results, the deposited films were annealed at 800 degrees C for 2 hours in air. Inasmuch as the magnetic and morphological properties are important for applications such as superconductive material vortex investigations, the produced films were investigated in details. The structural properties of the coatings were characterized by using XRD, SEM-EDS and AFM. The magnetic properties of the films were evaluated by the substitution of Bi and process conditions using VSM. The obtained results are presented.Öğe Synthesis and Characterization of Gd2O2SO4.Pr3+ Scintillation Material Produced by Sol-Gel Process for Digital Imaging System(Polish Acad Sciences Inst Physics, 2017) Aritman, I.; Yildirim, S.; Kisa, A.; Guleryuz, L. F.; Yurddaskal, M.; Dikici, T.; Celik, E.Scintillation materials are widely used in digital X-ray imaging applications, radiotherapy applications coupled with suitable photoreceptors. Gd2O2SO4 (GOS) scintillator doped with trivalent praseodymium (Pr3+) presented high X-ray absorption properties and good spectral compatibility which were utilized extensively for imaging system of X-ray microscopy, soft X-ray phosphor screen for water window. In this study, GOS:0.01Pr(3+) scintillation material was synthesized by unique sol-gel process which was not previously applied and its characterization properties were investigated. Structure and luminescence properties of GOS:Pr3+ were optimized by utilizing X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and luminescence spectroscopy.
