Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Access Right: Open AccessSubject: search.filters.subject.Antibacterial agents

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  • Master Thesis
    Development of Antibacterial Polymer Based Nanocomposite Materials
    (Izmir Institute of Technology, 2015) Abatay, Ezgi; Tanoğlu, Metin; Arslanoğlu, Alper; Arslanoğlu, Alper; Tanoğlu, Metin; 03.10. Department of Mechanical Engineering; 04.03. Department of Molecular Biology and Genetics; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    Human beings are often infected by microorganisms such as bacterium, mold, yeast, virus, etc. in the living environment. It became a requirement and a necessity to create sterile fields in areas. Composite stones are one of the main materials that can be used for the contact surfaces in indoor and outdoor places due to their being of highly resistant to abrasives, chemicals and impacts. Research has been intensive in antibacterial material containing various inorganic substances. The aim of this thesis is investigating the antibacterial effect of inorganic substances such as silver, zinc oxide, calcium oxide, titanium oxide and magnesium oxide on stone products. This study also deals with the silver doped zinc oxide powder and their antibacterial efficacies. Stone product is formed of mainly two type compound which are quartz aggregates as reinforced and filler and thermoset polyester resin as matrix. The manufacturing process begins with selection of raw quartz materials. They are crushed and blended in the ratio of 90 % quartz aggregates to 10% polyester matrix and other additives such as antibacterial agent, pigment. These united constituents are used for production of composite stones by applying those combined vacuum, vibration and pressing processes which are named as vibropress, simultaneously. Following it, they are subjected to surface preparation and polishing processes. In this study, mechanical, thermal, and morphological properties of the particles, polyester matrix and stone product were investigated. Antibacterial efficacies of these were investigated based on colony-count method against gram negative (E.coli) and gram positive (Bacillus subtilis) bacteria. Silver-containing stone samples showed best antibacterial property about ninety-nine percent reduction.
  • Master Thesis
    Effects of Chloride Ion and the Types of Oxides on the Antibacterial Activities of Inorganic Oxide Supported Ag Materials
    (Izmir Institute of Technology, 2007) Tunçer, Mert; Şeker, Erol; Şeker, Erol; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This study deals with the silver containing oxide supported materials and their antibacterial efficacies. Major goal of this study is to prepare silver chloride nano crystals on oxide supports to provide a long.lasting protection due to the slow and controlled release of silver ions from the materials. Two oxide supports, titanium dioxide and zinc oxide . silica matrices were synthesized via a sol-gel route which allows one to easily tailor textural and chemical properties. Two approaches were followed to form AgCl containing materials; to synthesize AgCl containing materials in a single step sol . gel route and to form AgCl in the materials by HCl treatment of metallic Ag containing oxide materials. The characterization of the samples were performed by using XRD, SEM, and BET techniques. Antibacterial efficacies of the powders were investigated by disk diffusion (zone inhibition) method against Gram negative E. coli bacteria. In the antibacterial activity tests, the powders containing metallic Ag and/or AgCl nano crystals were compared with the repeated usage to study the feasibility of their long term protection. In this study, it was found that AgCl nano-crytals containing samples showed a larger zone of inhibition than Ag containing samples in the standard media whose ingredient.s inhibitory effect on the antibacterial activity is the lowest. However, in the high broth containing media, metallic Ag nano-crystals containing samples showed higher zone of inhibition than AgCl containing samples which reveals the dependence of antibacterial activity on the type of media. In ZnO . SiO2 samples, the highest antibacterial activity was found unexpectedly at the lowest ZnO concentration. Moreover, Ag containing ZnO . SiO2 was found to be more active than Ag containing TiO2 samples. As the antibacterial tested samples were investigated by XRD, it was seen that Ag crystals were formed into AgCl crystal because of the Cl ions present in the broth media. AgCl formation indicates that there is an interaction between the content of growth media and the antibacterial materials.
  • Master Thesis
    Cation Exchange (ag+, Zn2+, Cu2+) Behavior of Natural Zeolites
    (01. Izmir Institute of Technology, 2001) Top, Ayben; Ülkü, Semra; Top, Ayben; Ülkü, Semra; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, clinoptilolite, most abundant zeolite present in nature, was proposed as a low cost antibacterial material. As a preliminary work, antibacterial activities of the original, Ag, and Zn forms of the clinoptilolite were investigated against several strains and compared to the commercial antibiotics. No antibacterial action was observed for the original clinoptilolite. Ag loaded clinoptilolite was found to be superior to the Zn-form against Proteus spp. and Pseudomonas aeruginosa.The original, Na, Ag, Zn, and Cu forms of the clinoptilolite samples were characterized by FTIR spectroscopy, thermal analyses (TGA, DTA, and DSC), and N2 physisorption studies. Specific attention was given in to the chemical analysis of the clinoptilolite by ICP-AES. Using the standard addition method, the respective idealized formulas of the original and Na-clinoptilolite based on 72 oxygen atoms in the unit cell were calculated as:(Na0.816 K2.070) (Ca1.060 Mg0.264) (Al5.653 Fe0.390) (Si30.084) O72. 20.023 H2O, and (Na4.763 K1.057) (Ca0.076 Mg0.094) (Al5.843 Fe0.221) (Si29.911) O72.17.049 H2O.In the FTIR spectra of the original and exchanged forms of the clinoptilolite, considerable shifts (from 3460 to 3494.8 cm-1) were observed in the band, which is formed due to the interactions of water molecules with the framework via hydrogen bonds. The positions of the other bands were not affected by cation exchange significantly. From the TGA curves, the water contents ranged between 14.31 and 11.00 % for the original and the cation-exchanged forms of the clinoptilolite. Mainly, two endotherms and one exotherm were obtained in the DTA curves. The first endotherm occurred up to about 150 oC, the second endotherm lied between 200 and 700 oC, and the exotherm was obtained at about 850 oC. Significant differences observed between the shapes of the DSC curves indicated that the cations control the dehydration behavior of the samples. N2 physisorption isotherms of five samples were all, Type IV with BET surface areas ranging between 34.97 and 46.76 m2/g.Ag, Zn and Cu ion exchange equilibria were investigated at 25 oC for both the original clinoptilolite and Na-clinoptilolite. In the former case, from the plateau of the isotherms cation exchange capacities were determined as 1.184, 0.439, 0.539 meq/g clinoptilolite for Ag+, Zn2+, and Cu2+ respectively. The major portion of the exchanges was contributed by Na+ and Ca2+. Distribution coefficient values indicated that at Ag, Zn and Cu ion exchange equilibria were investigated at 25 oC for both the original clinoptilolite and Na-clinoptilolite. In the former case, from the plateau of the isotherms cation exchange capacities were determined as 1.184, 0.439, 0.539 meq/g clinoptilolite for Ag+, Zn2+, and Cu2+ respectively. The major portion of the exchanges was contributed by Na+ and Ca2+. Distribution coefficient values indicated that at relatively low initial concentrations, the preference of the clinoptilolite for Zn2+ and Cu2+ was significant. At higher concentrations, higher distribution coefficients were obtained for Ag+ compared to Zn2+ and Cu2+. Langmuir and Freundlich models were applied for each equilibrium data. For Zn2+ and Cu2+ exchanges, Langmuir model gave better correlation and Freundlich model fitted experimental data slightly better in the case of Ag+ exchange.Equilibrium isotherms for Ag+-Na+, Zn2+-Na+, and Cu2+-Na+ pairs were investigated. Silver exchange isotherm lied above the diagonal over the whole composition range. For zinc and copper exchanges, the isotherms were above the diagonal up to equivalent fractions of exchanging ion in solution phase (As) at about 0.2. While full exchange was attained for silver, partial exchanges were obtained in the case of zinc and copper. The standard free energy of exchange values were found as .6.0, 2.03 and 3.09 kj/equiv for Ag+-Na+, Zn2+-Na+, and Cu2+-Na+ pairs respectively. From these values selectivity sequence was obtained as Ag+ > Na+ > Zn2+ > Cu2+.Consequently, by considering the preliminary antibacterial activity results, specific cation exchange capacities, and selectivity sequence of the clinoptilolite, Ag-clinoptilolite seemed to be promising antibacterial material. The results of the current study compared to the literature data pointed out that cation exchange behavior of the clinoptilolite is dependent on its original cationic composition. Therefore, it is necessary to carry out specific studies on representative samples from the deposit before any practical application.