Aydemir, Ümran

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Aydemir, U.
A., Umran
U.,Aydemir
Ümran, Aydemir
A.,Ümran
Ü.,Aydemir
Aydemir, Umran
Aydemir,U.
Aydemir,Ü.
U., Aydemir
A.,Umran
Umran, Aydemir
Aydemir, Ümran
Sezer, Umran Aydemir
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Araştırma Görevlisi
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Scholarly Output

6

Articles

6

Citation Count

122

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0

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2011 - 20146
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Now showing 1 - 6 of 6
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    Article
    Citation Count: 18
    Poly(ε-caprolactone) Composite Scaffolds Loaded with Gentamicin-Containing β-Tricalcium Phosphate/Gelatin Microspheres for Bone Tissue Engineering Applications
    (Wiley, 2014) Aydemir, Ümran; Arslantunali, Damla; Aksoy, Eda Ayse; Hasirci, Vasif; Hasirci, Nesrin; Chemical Engineering
    In this study, novel poly(epsilon-caprolactone) (PCL) composite scaffolds were prepared for bone tissue engineering applications, where gentamicin-loaded -tricalcium phosphate (-TCP)/gelatin microspheres were added to PCL. The effects of the amount of -TCP/gelatin microspheres added to the PCL scaffold on various properties, such as the gentamicin release rate, biodegradability, morphology, mechanical strength, and pore size distribution, were investigated. A higher amount of filler caused a reduction in the mechanical properties and an increase in the pore size and led to a faster release of gentamicin. Human osteosarcoma cells (Saos-2) were seeded on the prepared composite scaffolds, and the viability of cells having alkaline phosphatase (ALP) activity was observed for all of the scaffolds after 3 weeks of incubation. Cell proliferation and differentiation enhanced the mechanical strength of the scaffolds. Promising results were obtained for the development of bone cells on the prepared biocompatible, biodegradable, and antimicrobial composite scaffolds. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40110.
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    Article
    Citation Count: 15
    Poly(ε-caprolactone) composites containing gentamicin-loaded β-tricalcium phosphate/gelatin microspheres as bone tissue supports
    (Wiley, 2013) Aydemir, Ümran; Aksoy, Eda Ayse; Hasirci, Vasif; Hasirci, Nesrin; Chemical Engineering
    In this work, novel antibacterial composites were prepared by using poly(epsilon-caprolactone) (PCL) as the main matrix material, and gentamicin-loaded microspheres composed of beta-tricalcium phosphate (beta-TCP) and gelatin. The purpose is to use this biodegradable material as a support for bone tissue. This composite system is expected to enhance bone regeneration by the presence of beta-TCP and prevent a possible infection that might occur around the defected bone region by the release of gentamicin. The effects of the ratio of the beta-TCP/gelatin microspheres on the morphological, mechanical, and degradation properties of composite films as well as in vitro antibiotic release and antibacterial activities against Escherichia coli and Staphylococcus aureus were investigated. The results showed that the composites of PCL and beta-TCP/gelatin microspheres had antibacterial activities for both bacteria. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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    Article
    Citation Count: 6
    Semi-IPN chitosan/polyvinylpyrrolidone microspheres and films: sustained release and property optimisation
    (Taylor & Francis Ltd, 2013) Aydemir, Ümran; Sezer, Umran Aydemir; Gurhan, Ismet Deliloglu; Iz, Sultan Gulce; Hasirci, Nesrin; Chemical Engineering
    A set of chitosan-polyvinylpyrrolidone (CH-PVP) microspheres were prepared as semi-inter penetrating networks (semi-IPN) and loaded with 5-fluorouracil. In vitro release studies showed faster release for semi-IPN microspheres compared to pure CH samples, and the total release was achieved in about 20-30 days, depending on the composition. In vitro cell studies were achieved against human breast adenocarcinoma cell line cells where adsorption of cells on microspheres with a significant decrease in their number was obtained. Meanwhile, the CH-PVP films, which were prepared with the same compositions as in the microspheres, demonstrated an increase in strength from 66 to 118 MPa as the PVP content was decreased. It can be concluded that the prepared CH-PVP semi-IPN microspheres are novel promising carriers compared to pure CH microspheres since it becomes possible to adjust stability and hydrophilicity of the microspheres as well as the release rates of the drugs from the microspheres by changing the ratio of CH/PVP composition.
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    Article
    Citation Count: 28
    Semi-IPN Chitosan/PEG Microspheres and Films for Biomedical Applications: Characterization and Sustained Release Optimization
    (Amer Chemical Soc, 2012) Aydemir, Ümran; Sezer, Umran Aydemir; Iz, Sultan Gulce; Gurhan, Ismet Deliloglu; Hasirci, Nesrin; Chemical Engineering
    Micro drug carriers are one of the efficient methods for local or systemic cancer treatment. In this study, the aim was to prepare a novel semi-interpenetrated (semi-IPN) micro system by using biocompatible chitosan (CH) and polyethylene glycol (PEG). Various combinations of the systems were prepared and loaded with a model chemotherapeutic drug, methotrexate (MTX), and the effects of composition on the properties and the release behavior of microspheres were examined. Also, the mechanical and thermal properties were examined on film forms of similar compositions. Increase in cross-linking caused a decrease in particle size of CH from 144 to 91 mu m, while the addition of PEG caused an increase up to 163 mu m. Elastic modulus values of the films first increased and then decreased parallel to PEG content. In vitro studies showed faster MTX release from semi-IPN CH-PEG microspheres as compared to pure CH ones. Promising results were obtained in the development of biodegradable drug vehicles.
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    Article
    Citation Count: 8
    Gentamicin loaded β-tricalcium phosphate/gelatin composite microspheres as biodegradable bone fillers
    (Wiley, 2012) Aydemir, Ümran; Aksoy, Eda Ayse; Durucan, Caner; Hasirci, Nesrin; Chemical Engineering
    In this study, novel composite bone fillers with microspherical shape, biodegradable property, and antibacterial effect were designed and prepared. Various fillers with different beta-tricalcium phosphate (beta-TCP)/gelatin (G)/glutaraldeyde (GA) compositions were loaded with a model antibiotic, gentamicin. The effect of composition and preparation conditions on the release of gentamicin was investigated in in vitro conditions. Complete release were observed in 12 h for pure beta-TCP powder, and this period was extended up to 96 h as the gelatin content increased in the microspheres. Morphological and chemical structures of the microspheres, before and after the release studies, were investigated by scanning electron microscopy and Fourier transform infrared, respectively. Antibacterial activities were examined against Escherichia coli by using disc diffusion method and promising results were obtained. It is proposed that these novel beta-TCP/G/GA microspheres can be applied locally to prevent and/or eliminate infection that might occur around a defected region of hard tissue and supports the healing process. POLYM. COMPOS., 2012. (c) 2012 Society of Plastics Engineers
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    Article
    Citation Count: 47
    Forward and reverse bias current-voltage characteristics of Au/n-Si Schottky barrier diodes with and without SnO2 insulator layer
    (Elsevier, 2011) Aydemir, Ümran; Altindal, S.; Karaman, Mehmet; Aydemir, U.; Chemical Engineering; Physics Group
    The effects of interfacial insulator layer, interface states (N-ss) and series resistance (R-s) on the electrical characteristics of Au/n-Si structures have been investigated using forward and reverse bias current-voltage (I-V) characteristics at room temperature. Therefore, Au/n-Si Schottky barrier diodes (SBDs) were fabricated as SBDs with and without insulator SnO2 layer to explain the effect of insulator layer on main electrical parameters. The values of ideality factor (n), R-s and barrier height (Phi(Bo)) were calculated from ln(I) vs. V plots and Cheung methods. The energy density distribution profile of the interface states was obtained from the forward bias I-V data by taking bias dependence of ideality factor, effective barrier height (Phi(e)) and R-s into account for MS and MIS SBDs. It was found that N-ss values increase from at about mid-gap energy of Si to bottom of conductance band edge of both SBDs and the MIS SBD's N-ss values are 5-10 times lower than those of MS SBD's. An apparent exponential increase from the mid-gap towards the bottom of conductance band is observed for both SBDs' (MS and MIS) interface states obtained without taking R-s into account. (C) 2011 Elsevier B.V. All rights reserved.