Browsing by Author "Ak M."

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    Investigation of the prevalence of amoebiasis in Izmir province and determination of Entamoeba spp. using PCR and enzyme immunoassay
    (2008) Kurt O.; Demirel M.; Ostan I.; Sevil N.R.; Mandiracioglu A.; Tanyuksel M.; Ak M.; Dagci H.
    Amoebiasis is a common and life-threatening disease. The discrimination of the pathogenic Entamoeba histolytica from the non-pathogenic Entamoeba dispar could be done by advanced methods such as enzyme immunoassay (EIA) and PCR. The aim of this study was to investigate the prevalence of amoebiasis in Izmir province, and differentiate the Entamoeba species by PCR and EIA. Stool samples of 2,047 individuals were examined by direct microscopy, formalin ethyl acetate concentration, trichrome staining and culture, and those found to be positive for E. histolytica/dispar by any of these methods were further analyzed by PCR and EIA for species identification. Fifty-nine of 2,047 (2.9%) stool samples were found to be positive for E. histolytica/dispar with microscopy and/or culture. Among these positive samples, E. histolytica was detected in 14 (23.7%) and 5 (8.5%) samples with PCR and antigen-specific ELISA (EIA), respectively. E. dispar was diagnosed in 31 (52.5%) and 52 (88.1%) of 59 samples with species-specific PCR and EIA, respectively. Risk factors related to infection with Entamoeba spp. and other intestinal parasites included living in shanty houses (p<0.01), a history of recent immigration to Izmir (p<0.01), having no social security (p<0.05) and living with a crowded family (p<0.01). The results demonstrated the significance of amoebiasis as a public health problem among people with low socio-economic status in Izmir province.
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    The prevalence of intestinal parasites in the province of Izmir, Turkey
    (2008) Dagci H.; Kurt Ö.; Demirel M.; Östan I.; Azizi N.R.; Mandiracioglu A.; Yurdagül C.; Tanyüksel M.; Eroglu E.; Ak M.
    Stool samples of a total of 2,047 people in Izmir province were examined by wet mount, formalin ethyl acetate concentration, and trichrome staining methods with an aim to reveal the prevalence of intestinal parasites in Izmir together with related personal and environmental risk factors. Geographical mapping showing the density and variation of the species of intestinal parasites in Izmir was done after all maps were scaled, and the coordinates were determined with GeoMedia5.0®. The prevalence of the intestinal parasites was found to be 25.6 % in Izmir, with a variation between the districts. Blastocystis hominis was the leading parasite, and the prevalence of parasites was higher in children compared to adults; however, the difference was statistically insignificant. There was also no significant difference between the parasite prevalence and sex, marital status, education, income, frequent eating outside, and habitual raw meat eating. Significant differences were found between the parasite prevalence and crowded families, early immigrants, individuals with no social security, and people living in close contact with their livestock. The parasites were found to be less common among individuals who had been drinking bottled water and living in a house with a sewage system. The results demonstrated a correlation between the intestinal parasites and environmental conditions in our study group. We further plan to expand the study group to cover all regions of Turkey. © 2008 Springer-Verlag.
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    Thermal degradation kinetics and thermodynamics of maleimide-sytrene based alternating copolymer: A comparative investigation of monomer and polymer structures
    (Elsevier B.V., 2020) Koyundereli Çılgı G.; Ak M.
    Thermal degradation of N-(4-(3-Thienyl methylene)-oxycarbonylphenyl) maleimide monomer, MT and its copolymer with styrene, P(MT-alt-St) were investigated comparatively using TG and DTA methods. Degradation of monomer takes place in three stages which correspond to removal of thiophene, aliphatic groups and the rest of structural decomposition respectively. Degradation of the copolymer occurs in two stages. Thiophene and aliphatic groups decompose simultaneously at the first degradation stage. The main polymeric chain remains intact. The second stage is related to the rest of structural decomposition. Activation energy values of these reactions were calculated by using Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. In order to determine the effective reaction model and calculate thermodynamic parameters, these methods were combined with modeling equations. It was found that the first degradation stages of monomer and copolymer show good harmony with diffusion model (D1), whereas nucleation and growth model (A2) is effective for the second decomposition stage of the monomer. © 2020
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    Enhancing solar thermal storage properties of azobenzenes with conductive polymer: Electropolymerization of carbazole containing photoactive cyanoazobenzene derivative
    (Elsevier Ltd, 2023) Sert S.; Ayranci R.; Çılgı G.K.; Ak M.
    Solar thermal fuels (STFs) have recently drawn attention as a promising strategy for utilization of solar energy that is a clean and renewable source. Especially solid state solar thermal fuels have high potential to be used in thermal applications. However, up to date, it is seen that the solar thermal storage capacity in the polymeric state is lower than in the corresponding monomers. Herein, for the first time, photoactive azobenzene and electroactive carbazole containing monomer (Cz-AzoCN) was designed and thermal storage properties of the monomer and the corresponding polymer obtained by electropolymerization were investigated. This study showed that polycarbazoles containing azobenzene pendant groups can be an effective thermal storage platform due to their easy functionality, high light absorption and rigid conjugated chain structure resembling the structure of rigid templates decorated with closely packed photochromic units. Additionally, electropolymerization is an easy and rapid method for polymer synthesis, producing polymer in the form of film that is ready for irradiation. The gravimetric energy storage density of p(Cz-AzoCN) was calculated as 145.12 j g−1 which was 128 % higher than that of monomer. This is due to boosted light harvesting of conjugated polycarbazole backbone as an organic photosensitizer that providing effective solar thermal storage. © 2023 Elsevier Ltd
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    Photoresponsive conductive polymer network based on azobenzene bridging crosslinked polycarbazole for boosting solar thermal storage
    (Elsevier B.V., 2024) Sert S.; Ayranci R.; Çılgı G.K.; Ak M.
    Azobenzene is one of the most extensively researched multifunctional chromophores and azobenzene including materials has a wide variety of applications due to their photoisomerization behavior. In this study, electroactive and light-harvesting carbazole and photoresponsive azobenzene units have been combined with a special macromolecular design. In this design the azo groups can be effectively isomerized in solid state, and free-standing films can be obtained by the electrochemical method. Thermal characterizations of both monomer and polymer have been performed and isomerization kinetics and solar-thermal properties have been investigated. The half-life at 60 °C and the gravimetric energy storage density of polymer was calculated as 103 min and 179.9 j g−1, respectively. Cross-linked polycarbazole structure causes dramatically increased solar thermal storage and half-life compared to respective monomer and brought unexpected mechanical and solvatochromic properties. © 2024 Elsevier B.V.