Öztürk, Temel | Göktaş, Melahat | Hazer, Baki

Article | 2010 | Journal of Applied Polymer Science117 ( 3 ) , pp.1638 - 1645

One-step synthesis of star copolymers by reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) by using a novel dual initiator is reported. Triarm block copolymers comprising one polystyrene (or polyacrylamide) arm and two poly(b-butyrolactone) arms were synthesized in one-step by simultaneous RAFT polymerization of styrene (St) (or acrylamide, designated as AAm) and ROP of b-butyrolactone (BL) in the presence of a novel trifunctional initiator, 1,2-propanediol ethyl xanthogenate (RAFT-ROP agent). This dual initiator was obtained through the reaction of 3-chloro-1,2- propanediol with the potas . . .sium salt of ethyl xanthogenate. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one-step polymerization reaction were evaluated. The characterization of the products was achieved using Fourier-transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance (1HNMR),13C-nuclear magnetic resonance ( 13C-NMR), Gas chromatography-mass spectrometry (GC-MS), gel-permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (c) techniques. VC 2010 Wiley Periodicals, Inc Daha fazlası Daha az

Öztürk, Temel | Yılmaz-Savaşkan, Sevil | Hazer, Baki | Menceloğlu, Yusuf Z.

Article | 2010 | Journal of Polymer Science, Part A: Polymer Chemistry48 ( 6 ) , pp.1364 - 1373

This article reports the synthesis of the block and graft copolymers using peroxygen-containing poly(methyl methacrylate) (poly-MMA) as a macroinitiator that was prepared from the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in the presence of bls(4,4'-bromomethyl benzoyl peroxide) (BBP). The effects of reaction temperatures on the ATRP system were studied in detail. Kinetic studies were carried out to investigate controlled ATRP for BBP/CuBr/bpy initiating system with MMA at 40 °C and free radical polymerization of styrene (S) at 80 °C The plots of In ([M o]/[Mt]) versus reaction time are linear, corresp . . .onding to first-order kinetics. Poly-MMA initiators were used In the bulk polymerization of S to obtain poly (MMA-b-S) block copolymers. Poly-MMA initiators containing undecomposed peroygen groups were used for the graft copolymerization of polybutadiene (PBd) and natural rubber (RSS-3) to obtain crosslinked poly (MMA-g-PBd) and poly(MMAg-RSS-3) graft copolymers. Swelling ratio values (q v) of the graft copolymers in CHCl3 were calculated. The characterizations of the polymers were achieved by Fourier-transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance (1H NMR), gelpermeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and the fractional precipitation (?) techniques. © 2010 Wiley Periodicals, Inc Daha fazlası Daha az

Kalaycı, Özlem A. | Cömert, Füsun B. | Hazer, Baki | Atalay, Turgay | Cavicchi, Kevin A. | Çakmak, Mükerrem

Article | 2010 | Polymer Bulletin65 ( 3 ) , pp.215 - 226

The synthesis, spectroscopic characterization, and antimicrobial efficiency of gold and silver nanoparticles embedded in novel amphiphilic comb-type graft copolymers having good film-forming properties have been described. Amphiphilic comb-type graft copolymers were synthesized by the reaction of chlorinated polypropylene (PP) (Mw = 140,000 Da) with polyethylene glycol (PEG) (Mn = 2,000 Da) at different molar ratios. Metal nanoparticles embedded graft copolymers were prepared by reducing solutions of the salts of silver or gold and the copolymer in tetrahydrofuran. The optical properties of the metal nanoparticle embedded copolymers . . . were determined by using UV-visible spectroscopy. Surface plasmon resonance (SPR) of the gold and silver nanoparticle embedded copolymers in toluene was observed at a maximum wavelength (?max) of 428 and 551 nm in the UV-VIS absorption spectra, respectively. The average particle diameters of the gold and silver nanoparticles were found to be 50 nm from the high resolution scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Amphiphilic polymer films containing silver and gold nanoparticles were found to be highly antimicrobial by virtue of their antiseptic properties to Escherichia coli and Staphylococcus aureus. © Springer-Verlag 2009 Daha fazlası Daha az

Özaçmak, Veysel Haktan | Özaçmak-Sayan, Hale

Other | 2010 | Türk Geriatri Dergisi13 ( 3 ) , pp.160 - 165

Giriş: Turmeriğin majör komponenti olan kurkumin hem antioksidan hem de antiinflamatuar aktivite göstermektedir. Çalışmamızda, kronik serebral hipoperfüzyon modelini kullanarak, overleri alınmış dişi sıçan beyininde, kurkuminin oksidatif stresi azaltıp azaltmadığını araştırdık. Gereç ve Yöntem: Kronik serebral hipoperfüzyon, her iki karotid komunis arterin kalıcı ligasyonu ile sağlandı. Denekler (4-6 aylık toplam 30 adet yetişkin Wistar Albino dişi sıçanlar) rastgele üç gruba ayrıldı: sham kontrol, iskemi ve 14 gün boyunca günlük kurkumin (100 mg/kg) verilen iskemi grubu. Ligasyon sonrası 14üncü günde tüm gruplardaki beyin dokuların . . .ın malondialdehid (MDA) ve indirgenmiş glutatyon (GSH) içerikleri ölçüldü. Bulgular: İskemi, MDA içeriğinin ileri dercede yükselmesine neden olurken GSH seviyesini anlamlı derecede azalttı. Diğer yandan, kurkumin tedavisi iskemik beyin dokusunda anlamlı derecelerde MDA düzeyini düşürerek ve GSH içeriğini yükselterek, değerlerin sham grubundakiler seviyesine geri dönmesini sağladı. Sonuç: Elde ettiğimiz sonuçlar, vasküler demansın deneysel hayvan modeli olan kronik serebral hipoperfüzyonda kurkuminin hem oksidatif stresi hem de lipid peroksidasyonunu azalttığını önermektedir. Altta yatan moleküler mekanizmaların derinlemesine daha fazla araştırılması sonrasında inanıyoruz ki kurkuminin tedavideki verimliliği, klinik uygulamalar için özellikle de vasküler demanslı menopoz sonrası yaşlı kadınlarda test edilmesine layık olacaktır. Introduction: Curcumin, the major constituent of turmeric, exhibits both antioxidant and anti-inflammatory activities. In the present study, we investigated whether or not curcumin reduces oxidative stress in ovariectomized female rat brain by using a model of chronic cerebral hypoperfusion. Materials and Method: Chronic cerebral hypoperfusion was induced by permanent ligation of both common carotid arteries. Animals (a total of 30 adult female Wistar Albino rats, 4-6 months old) were randomly divided into three groups: sham control, ischemia, and ischemia plus daily curcumin treatment (100 mg/kg) for 14 days. At day 14 after the ligation, malondialdehyde (MDA) and reduced glutathione (GSH) contents of brain tissues were measured in all groups. Results: Ischemia caused a significant increase in MDA content but a meaningful decrease in GSH levels. Treatment with curcumin, however, lowered MDA and elevated GSH contents significantly in ischemic brain tissue, bringing their levels back to that of the sham group. Conclusion: Our results suggest that curcumin attenuates both oxidative stress and lipid peroxidation in chronic cerebral hypoperfusion, which is an animal model of vascular dementia. Following further in depth investigations into underlying molecular mechanism(s), we believe that therapeutic efficacy of curcumin deserves to be tested for potential clinical application especially in postmenopausal elderly women suffering from vascular dementia Daha fazlası Daha az

Balcı, Murat | Allı, Abdulkadir | Hazer, Baki | Güven, Olgun | Cavicchi, Kevin | Çakmak, Mükerrem

Article | 2010 | Polymer Bulletin64 ( 7 ) , pp.691 - 705

Çakmakçı, Mehmet | Kınacı, Cumali | Bayramoğlu, Mahmut | Yıldırım, Yılmaz

Article | 2010 | Expert Systems with Applications37 ( 2 ) , pp.1369 - 1373

Effluent iron concentration is an important water quality criterion used for the assessment of the performance of rapid sand filters, in addition to other criteria. This study deals with the prediction of effluent iron concentrations by adaptive neuro-fuzzy (ANFIS) model with input parameters including filter hydraulic loading rate, influent iron concentration, bed porosity and operation time. With trying various types of membership functions, two rule base generation methods, namely subtractive clustering and grid partition were used for a first order Sugeno type inference system. Models were evaluated using root mean squared error . . . (RMSE), index of agreement (IA) and R2 as statistical performance parameters. The fit between experimental results and model outputs showed good agreement for tap water and deionized water; testing RMSE values were 36.33 and 7.66 µg/L, the IA values were 0.996 and 0.971, and R2 values were 0.99 and 0.89, respectively. It was concluded that neuro-fuzzy modeling may be successfully used to predict effluent iron concentration in sand filtration. © 2009 Elsevier Ltd. All rights reserved Daha fazlası Daha az

Altın, Ahmet | Bakır, Fatma | Özölçer, İsmail Hakkı

Article | 2010 | WATER RESOURCES MANAGEMENT24 ( 4 ) , pp.747 - 759

KurtbogazA +/- Dam is one of the most significant sources of drinking water sources for Ankara City. In this study, hydro-geochemical properties and pollution sources of surface waters feeding into the dam are determined. In addition, important environmental problems such as squatter's houses and wastewater discharges within protection zones of watershed of the dam are defined and appropriate precautions are discussed. The long-term trend (1998-2007) in water quality results of the dam and the surface waters in the KurtbogazA +/- watershed were studied, utilizing data provided by General Directorate of State Water Works (DSI). The r . . .esults indicate that waters in the watershed can be classified as waters with calcium-bicarbonate. Due to the drought conditions experienced in recent years, the concentrations of the organic materials and nitrogen and phosphorus compounds in the surface waters have increased dramatically since 2005. It is thought that wastewaters discharged by the settlements within the watershed (especially Pazar Township) are responsible for these increases. Preventing wastewater discharges from the squatter's houses and agricultural activities on the absolute and the proximate zones of the watershed and the constructing of a sewerage and treatment plant are the first challenges for the protection of the watersheds Daha fazlası Daha az

Genç, Ayten | Oğuz, Aşkın

Article | 2010 | Desalination264 ( 01.Feb ) , pp.78 - 83

The sorption of two acid dyes (Acid Yellow 99 and Acid Red 183) into locally available industrial waste materials, namely, Granulated Blast Furnace Slag (GBFS) and Furnace Bottom Ash (FBA), has been investigated by performing batch equilibrium experiments with pH, ionic conductivity, initial dye concentration and temperature as variables. The kinetic sorption data indicated that the sorption capacity of GBFS for these dyes was almost zero. On the other hand, the color removal efficiency for FBA could reach 50% depending on the initial dye concentration. It was also found that the kinetics of sorption of Acid Yellow 99 and Acid Red 1 . . .83 onto the surface of FBA at different operating conditions were best described by the Elovich kinetic model. In addition, the adsorption equilibrium data were analyzed using various adsorption isotherm models and the results have shown that the sorption behaviors of the studied dyes could be best described by the Langmuir model. © 2010 Elsevier B.V Daha fazlası Daha az

Genç, Ayten | Ulupınar, Elif

Article | 2010 | Transport in Porous Media84 ( 3 ) , pp.699 - 709

This study aimed to identify effects of pH on the transport of Pb2+ ions through a saturated silty-clayey soil layer by using advection-dispersion equation (ADE). The predictive accuracy of the solution of ADE depends on the proper determination of the retardation by adsorption and, therefore, the adsorption mechanism of lead onto silty-clayey soil was investigated first by performing batch equilibrium experiments. These results showed that the sorption mechanism of lead onto silty-clayey soil depended on pH and could be best described by the Langmuir isotherm. Based on the results of the sequential experiments, it was also conclude . . .d that the pH dependent charges in silty-clayey soil were mainly associated with the surfaces of carbonates and the specific adsorption of lead ions. The numerical solutions of the combined form of ADE with the Langmuir isotherm indicated that the migration profiles of lead in silty-clayey soil were a strong function of the parameters of the Langmuir isotherm rather than the infiltration velocity. © 2010 Springer Science+Business Media B.V Daha fazlası Daha az

Kandemir, Nilüfer Onak | Gün, Banu Doğan | Barut, Figen | Yurdakan, Gamze | Bahadır, Burak | Bektaş, Sibel | Gün, Mustafa | Keser, Sevinç Hallaç | Özdemir, Nagehan | Özdamar, Şükrü Oğuz

Article | 2010 | TURKDERM-TURKISH ARCHIVES OF DERMATOLOGY AND VENEROLOGY44 ( 2 ) , pp.73 - 78

Background and Design: Kaposi sarcomas (KS) are vascular tumors with a low malignant potential which include overlapping infectious, immunologic, and neoplastic processes. Recently, many histological subtypes have been defined. Material and Method: In the present study, 151 cutaneous classic KS lesions in 56 patients were retrospectively evaluated with regard to histological subtypes. Determination of the subtypes was based on the predominant histopathological component in the lesion. We examined changes in epidermis and dermis along with intratumoral inflammatory response characteristics in the lesions. By defining histopathologica . . .l variants of the cases, differences regarding subtypes were investigated. Results: Cases that bear the ordinary characteristics of KS and those that can not be classified otherwise, comprised 82..8% of the study group. Twenty-six cases showed consistency with the subtypes outlined in the literature in terms of their histopathological properties. The most common histological subtype was the lymphangiectatic variant in 7.3% of the cases. Bullous (2.6%), lymphangioma like (2.6%), intravascular (2%), and pyogenic granuloma like (2%) variants were less common. The most uncommon histological subtype was micronodular (0.6%) type. Lymphangiectatic, bullous, intravascular, and pyogenic granuloma like variants were frequently observed in the nodular stage of KSs. Lympangioma like changes were seen to be present in the early KS lesions. Lymphangiectatic type was oftenly associated with bullous component, whereas pyogenic granuloma like type demonstrated superficial ulceration and intense inflammatory response. Lymphangioma like and intravascular types exhibited a characteristic appearance, while other variants were accompanied by components belonging to different subtypes. Conclusion: In KS, histopathological subtypes can develop as a result of different pathological processes. The next stage of the current study, which is one of the largest case series in the literature, will be investigation of the clinical and prognostic characteristics of the variants. (Turkderm 2010; 44: 73-8 Daha fazlası Daha az

Hazer, Baki | Hazer, Derya Burcu | Çoban, Burak

Article | 2010 | Journal of Polymer Research17 ( 4 ) , pp.567 - 577

Microbial bioelastomers prepared by the autoxidation of the unsaturated medium-long chain length copoly- 3-hydroxyalkanoate's (mlcl-PHAs) based on soybean oily acids (Sy) have been reported. Pseudomonas oleovorans were grown on a series of the mixture of octanoic acid (OA) and Sy with the weight ratio of 20:80, 28:72 and 50:50 in order to obtain unsaturated mlcl-copolyesters coded PHO-Sy-2080, PHO-Sy-2872, and PHO-Sy-5050, respectively. The microorganism was also grown on the mixture of Sy and 10-undecenoic acid (UA) with the weight ratio of 50:50 to obtain unsaturated copolyester coded PHU-Sy-5050. The PHAs obtained were characteri . . .zed by 1H NMR and GC-MS techniques. Double bond contents of the unsaturated PHAs obtained were varying between 0.8 to 20 mol %. Autoxidation of the unsaturated copolyesters were carried out on exposure to air at room temperature in order to obtain new biomaterials whose mechanical strength was improved. Autoxidation kinetics, shelf life, mechanical and thermal properties of these biomaterials were evaluated Daha fazlası Daha az

Yıldız, Ufuk | Kemik, Ömer Ferkan | Hazer, Baki

Article | 2010 | Journal of Hazardous Materials183 ( 01.Mar ) , pp.521 - 532

Novel non-ionic hydrogels were synthesized by radical homopolymerization of N-vinyl-2-pyrrolidone (VP) or by radical copolymerization of VP with methylacrylate (MA). A macroinimer (MIM) was used as a crosslinker and initiator, as well. The percentage of mass swelling ratios (SM), the molecular weight between crosslinks (Mc) and Young's modulus of the hydrogels were investigated. The hydrogels were used as binding materials for different heavy metal ions such as Cu2+, Cd2+, Ni2+ and Zn2+ under varying conditions. The binding capability of the hydrogels toward the metal ions decreases in the following order: Cu2+>Ni2+>Zn2+>Cd . . .2+. © 2010 Elsevier B.V Daha fazlası Daha az