Phd Degree / Doktora

Permanent URI for this collectionhttps://hdl.handle.net/11147/2869

Browse

Filters

2010 - 20132

Settings

Department: search.filters.department.Thesis (Doctoral)--İzmir Institute of Technology, Chemical EngineeringSubject: search.filters.subject.Antioxidants

Search Results

Now showing 1 - 2 of 2
  • Doctoral Thesis
    Preparation and Characterization of Hemodialysis Membranes With Improved Biocompatibility Through Anticoagulant, Antioxidant and Enzyme Immobilization
    (Izmir Institute of Technology, 2013) Yaşar Mahlıçlı, Filiz; Alsoy Altınkaya, Sacide; Alsoy Altınkaya, Sacide; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The objective of this thesis is to improve blood compatibility of polysulfone (PSF) based hemodialysis membranes through generating thromboresistant and/or antioxidative surfaces with biomolecule immobilization. To create a nonthrombogenic surface, support membrane was modified with layer by layer (LBL) deposition of polyethyleneimine (PEI) and alginate (ALG) and heparin (HEP) was immobilized on the outermost surface of the assembly by blending with ALG. α-lipoic acid (ALA) and superoxide dismutase (SOD)/catalase (CAT) enzyme couple were choosen to provide antioxidative properties. ALA was immobilized site-specifically to PEI deposited support membrane while SOD/CAT enzyme couple were attached both covalently and ionically on the plasma treated and PEI deposited membranes, respectively. Blending a small amount of HEP with alginate remarkably prolonged the coagulation time (APTT) of HEP free membranes. The stability of ALA under typical hemodialysis conditions was improved by immobilization, and the greatest enhancement was achieved when it was sandwiched between two PEI layers. In vitro studies showed that all ALA or SOD/CAT coated PSF membranes are capable of reducing reactive oxygen species levels in blood, furthermore, they can significantly prolong APTT. The hemocompatibility results also demonstrated that the adsorption of human plasma proteins, platelet and cell activation on all modified membranes decreased significantly compared with the unmodified PSF membranes due to the change in surface properties such as hydrophilicity, surface charge and roughness upon immobilization of the biomolecules. The modification methods proposed in this study did not change high permeability, mechanical strength and nontoxic property of the PSF membranes.
  • Doctoral Thesis
    Recovery of Phytochemicals (having Antimicrobial and Antioxidant Characteristics) From Local Plants
    (Izmir Institute of Technology, 2010) Ülkü, Semra; Ülkü, Semra; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The objective of the present work was to assess the selective isolation of polyphenols from olive leaf and grape skin, which are supplied from the main local plants. The effects of extraction conditions on the types and amounts of polyphenolic compounds and selective separation of them by adsorption were investigated. The batch adsorption and dynamic column studies were performed by silk fibroin and clinoptilolite. Kinetic models were used to determine the mechanism of adsorption. Dynamic column models were applied to optimize the operating parameters. The biological activities of isolated fractions from the crude extracts were determined by analyzing their antioxidant, antimicrobial and cytotoxic activities. Recovered trans-resveratrol significantly inhibited all pathogenic microorganisms. However, higher concentration of grape skin crude extract is required to achieve same inhibition. Although grape skin extract did not have any effect on prostate and breast cancer cells, trans-resveratrol has very significant inhibition effect.