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Öğe Construction of a bioraactor for the degradation of the pesticide, aldicarb(1997) Kök F.N.; Arica M.Y.; Hasirci V.Water soluble derivatives of cellulose are widely used in various biomedical and biotechnological applications. Sodium carboxymethyl cellulose (25 ml, 1-4% w/v) was insolubilized in the form of microspheres using aluminum chloride (150 ml, 0.2-2.0 M) as the crosslinking agent. Microspheres were activated by epichlorohydrin. Methylophilus, a Gram negative bacteria capable of degrading aldicarb, a carbamate pesticide, was immobilized Methylophilus was determined by feeding in aqueous aldicarb solutions (10-400 ppm) at a rate of 20 ml/h. The degradative capability was found to be quite stable for ca. 48 h, and ca. 10% of the aldicarb was degradative capability was found to be quite stable for ca. 48 h, and ca. 10% of the aldicarb was found to be metabolized in the packed bed approach with a single pass application. © 1997 Elsevier B.V. All rights reserved.Öğe Controlled release of Aldicarb from carboxymethylcellulese microcapsules(1997) Arica M.Y.; Yiğtoğlu M.; Lale M.; Kök F.N.; Hasirci V.Sodium carboxymethyl cellulose was converted into microspheres by crosslinking with aluminum chloride. Various microsheres with different amounts of crosslinker, biopolymer of various concentrations and molecular weights, and with different pesticide (Aldicarb) contents and pesticide to polymer ratios were prepared. The pesticide encapsulation efficiencies and aldicarb release kinetics of the resultant microcapsules were investigated. It was possible to modify the release behaviour by varying the above parameters and to have drug release with half-lives longer than 100 hours in aqueous media. The release kinetics were described by first order and zero order kinetics.Öğe Low-molecular-weight heparin-conjugated liposomes with improved stability and hemocompatibility(Taylor and Francis Inc., 1998) Köse G.T.; Arica M.Y.; Hasirci V.Multilamellar vesicles (MLV) containing phosphatidyl choline (PC), cholestrol (CHOL), and stearylamine (SA) in the molar ratio of 7:2:0.2 were prepared by the thin film hydration method. Low-molecular-weight heparin (LMWH, MW: 3000) was conjugated with the MLV using carbodiimide (EDC). Infrared, Raman, and nuclear magnetic resonance spectra and DSC of each sample (MLV, LMWH, and MLV-LMWH) were obtained, enabling the authors to determine the chemical changes that occurred in the MLV structure at the end of the conjugation step. In addition, the changes in the chemical structures of the conjugated samples were revealed by the use of elemental analysis. Particle size analysis was used to determine the difference between the sizes of MLV and MLV-LMWH. In order to study the effect of LMWH on the behavior of MLV-LMWH in blood, osmotic fragility (in saline and plasma), hemolytic activity, and plasma recalcification time tests were carried out. These tests showed that it was possible to construct liposomes that would not induce reactions in the blood and would have potentially longer half-lives in the circulation.Öğe Novel hydrophobic ligand-containing hydrogel membrane matrix: Preparation and application to ?-globulins adsorption(Elsevier, 2001) Arica M.Y.; Akin-Öktem G.; Denizli A.In this study, phenylalanine as a hydrophobic ligand was covalently attached to the co-monomer methacrylochloride. Then, poly(2-hydroxyethylmethacrylate-co-methacrylamidophenyalanine) [poly(HEMA-MAPA)] membranes were prepared by UV-initiated photopolymerization of HEMA and methacrylamidophenyalanine. The ?-globulins adsorption onto these affinity membranes from aqueous solutions containing different amounts of ?-globulins at different pH was investigated in a batch system. The ?-globulins adsorption capacity of the membranes was increased as the ligand density on the membrane surface increase. The non-specific adsorption of the ?-globulins on the pHEMA membranes was negligible. The adsorption phenomena appeared to follow a typical Langmuir isotherm. The maximum adsorption capacity (qm) of the poly(HEMA-MAPA4) membrane for ?-globulins was 2.37 mg g-1dry membrane. The equilibrium constant (kd) value was found to be 1.61×10-1mg ml-1. More than 87% (up to 100%) of the adsorbed ?-globulins were desorbed in 120 min in the desorption medium containing 50% ethylene glycol in 1.0 M NaCl. Copyright © 2001 Elsevier Science B.V.Öğe Synthesis and spectroscopic characterization of superparamagnetic beads of copolymers of methacrylic acid, methyl methacrylate and ethylene glycol dimethacrylate and their application to protein separation(2008) Bayramoğlu G.; Arica M.Y.Novel magnetic beads were prepared from methacrylic acid, methyl methacrylate and ethylene glycol dimethacrylate in the presence of ferric ions via suspension polymerization. After polymerization, thermal treatment of the Fe(III)-ion containing beads with Fe(II) ions under alkaline condition resulted encapsulation of Fe3O4 crystals within the polymer matrix. The magnetic beads were characterized by surface area measurement, swelling tests, electron spin resonance (ESR), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and scanning electron microscopy (SEM). To evaluate the magnetic properties of the composite beads, Mössbauer spectra measurements were carried out. ESR and Mössbauer spectroscopy data revealed that the beads were highly superparamagnetic. The DSC data of the magnetic beads also showed an enhanced glass transition temperature owing to the presence of the Fe3O4 crystals within the polymer network. In addition, the presence of functional carboxyl groups on the surface permits further modifications in future applications. The magnetic beads were used for separation of human serum albumin and cytochrome c from aqueous solution in a batch system. © 2007 Society of Chemical lndustry.
