Özaçmak, Veysel Haktan | Sayan, Hale | Aktunç, Erol

Other | 2009 | Türk Biyokimya Dergisi34 ( 2 ) , pp.82 - 88

Amaç: Adenozin ve adenozin A1 reseptör agonistleri, çeşitli dokuların reperfüzyon harabiyetine karşı önkoşullanma yoluyla koruyucu etkiler göstermektedir. Çalışmanın amacı, sıçan ince bağırsağının reperfüzyon harabiyeti üzerine adenozin A1/A2 reseptör aktivasyonunun etkilerini incelemekti. Yöntemler: Denekler herbiri rastgele sekiz hayvan içeren dört gruba ayrıldı: sham kontrol, iskemi-reperfüzyon kontrol, 5’-N-etilkarboksiamidoadenozin (NECA) (non-selektif A1 /A2 agonisti, 0.1 mg/kg, i.v.) tedavili iskemi-reperfüzyon ve teofilin (non-selektif A1 /A2 antagonisti, 20 mg/kg, i.v.) tedavili iskemi-reperfüzyon. Tedaviler iskemi yapılmad . . .an 5 dk önce uygulandı. Süperiyor mezenter arter 30 dk klempe edildikten sonra reperfüzyon dönemi 180 dk sürdü. Terminal ileum segmentlerinin, KCl, karbakol ve substans P’ye olan kasılma yanıtlarının kaydedilmesinin yanısıra, dokuların miyeloperoksidaz, malondialdehit ve indirgenmiş glutatyon miktarları da ölçüldü. Bulgular: İskemi, nötrofil infiltrasyonu ve lipid peroksidasyonunu ileri düzeyde yükseltirken aynı zamanda indirgenmiş glutatyonu düşürdü. Sham control grubuy- la karşılaştırıldığında, kasılma yanıtları iskemi-reperfüzyon grubunda ciddi düzeyde azaldı. NECA ön tedavisi, doku indirgenmiş glutatyon miktarını ileri derecede düzeltti ve ayrıca iskemi-reperfüzyon sonucu azalmış kasılma yanıtını kısmen iyileştirdi. Teofilin ile ön tedavi ise herhangi koruyucu bir etki göstermedi. Sonuç: Adenozin A1 /A2 reseptör aktivasyonunun, iskemi sonucu gelişen bağırsak kasılma bozukluğuna karşı kısmi koruma sağladığını ve ayrıca bu korumanın, indirgenmiş glutatyon düzeyinin fizyolojik seviyede tutulması yolu ile muhtemelen gerçekleştiğine dair ek kanıt önermekteyiz. Objectives: Adenosine and adenosine A1 receptor agonists exert protective effects against reperfusion injury in different tissues by mediating preconditioning. The aim of the present study was to examine the effects of adenosine A1 /A2 receptor activation on reperfusion-induced small intestinal injury in rat. Methods: Animals were randomized into four groups each including eight as following: sham control, ischemia-reperfusion control, 5’-N-ethylcarboxamidoadenosine (NECA) (non-selective A1 /A2 agonist, 0.1 mg/kg, i.v.)-treated I/R, and theophylline (non-selective A1 /A2 antagonist, 20 mg/kg, i.v.)-treated I/R groups. The treatments were administered 5 min before inducing ischemia in which superior mesenteric artery was clamped for 30 min followed by 180 min of reperfusion pe- riod. Myeloperoxidase, malondialdehyde, and reduced glutathione contents of terminal ileum samples were measured besides recording contractile responses to KCl, carbachol and substance P. Results: Ischemic insult significantly increased neutrophil infiltration and lipid peroxidation while decreasing the reduced glutathione. Contractile responses were seriously reduced in I/R group compared to that of the sham control group. NECA pretreatment alleviated the tissue content of reduced glutathione remarkably besides providing partial amelioration of I/R-reduced contractile response, while theophylline pretreatment had no any protective effect. Conclusion: We offer additional evidence that activation of A1 /A2 adenosine receptors provides partial protection against ischemia-induced intestinal contractile dysfunction possibly through maintaining reduced glutathione content at physiological levels Daha fazlası Daha az

Hazer, Baki | Hirao, Akira | Volga, Cüneyt

Article | 1999 | Macromolecular Chemistry and Physics200 ( 1 ) , pp.71 - 76

In order to synthesize benzoyl peroxide functionalized polystyrene (PSt), polyisoprene (PI) and poly(methyl methacrylate) (PMMA), anionic living PSt, PI, and PMMA were allowed to react with an excess amount of 4-(bromomethyl)benzoyl tert-butyl peroxide (BMtB) or bis[3,5-bis(bromomethyl)benzoyl] peroxide (BDBP) in tetrahydrofuran (THF) at -78°C. The results indicate that coupling reactions leading to dimers are significant during the reaction. Dimer formation was avoided when the living polystyrene was modified to the alcoholate anion by reaction with ethylene oxide (EO). © Wiley-VCH Verlag GmbH, 1999.

Menteş, Ayger | Sarbay, Mithat | Hazer, Baki | Arslan, Hülya

Article | 2005 | Applied Organometallic Chemistry19 ( 1 ) , pp.76 - 80

Mo(CO)6 was reacted with the Schiff base ligand obtained by condensation reaction of 2-acetyl- or benzoylpyridine with poly(propylene glycol)bis(2-aminopropyl ether) to obtain polymeric, dinuclear metal tetracarbonyl compounds. The long-chain Schiff base complexes are highly soluble even in non-polar solvents such as petroleum ether, diethyl ether and n-hexane. These complexes, as free-radical initiators, afforded methyl methacrylate polymerization in chlorinated solvents. Copyright © 2004 John Wiley & Sons, Ltd.

Tığlı-Aydın, Rahime Seda | Kazancı, Füsun

Article | 2018 | JAOCS, Journal of the American Oil Chemists' Society95 ( 11 ) , pp.1385 - 1398

In recent years, the use of ozonated oil (ozone enriched oil form) is being increasingly preferred for biomedical applications because of its antibacterial activity. Among most important reasons of this choice is the high molecular affinity of the ozone molecule and intracellular effects of the products of ozone and the unsaturated fatty-acid chemical reactions in cellular signaling systems. The aim of the present study was to synthesize and optimize the ozonated oil nanoemulsion system that would be transferred into the living systems easily, suggesting a promising carrier system for various biomedical applications. By varying form . . .ulation parameters (surfactant-to-oil ratio, surfactant concentration, mixing rate, and surfactant type), nanoemulsions were investigated in terms of mean particle diameters, distributions, and stabilities. Nanoemulsions with high stability and small droplet diameters (212.7 nm) could be produced under optimized conditions with Tween 40 as the surfactant at a 750 rpm mixing rate using the emulsion inversion point (EIP) low-energy method. Spherical and uniformly distributed nanoemulsions were observed by SEM, which also supports mean particle diameter measurements. Fourier-transform infrared spectroscopy (FTIR) and 13C NMR (nuclear magnetic resonance) studies indicated an ozonide structure within the nanoemulsion system, which remained even after 30 days of storage. The antibacterial activity of ozonated oil emulsions against Staphylococcus aureus and Escherichia coli suggests promising applications in the biomedical field. © 2018 AOC Daha fazlası Daha az

Macit, Hülya | Hazer, Baki

Article | 2004 | Journal of Applied Polymer Science93 ( 1 ) , pp.219 - 226

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly-THF)-polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF6 and bis(4,4' bromo-methyl benzoyl) peroxide (BBP) or bis (3,5,3',5' dibromom-ethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly-THF initiators with MW varying from 7,500 to 59,000 Da. Poly-THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C . . .to obtain poly(THF-b-MMA) block copolymers containing the peroxide group in the middle. Poly(MMA-b-THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA-b-PTHF-b-PMMA and PMMA-b-PTHF-PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT-IR, DSC, TGA, 1H-NMR, and 13C-NMR techniques and the fractional precipitation method. © 2004 Wiley Periodicals, Inc Daha fazlası Daha az

Macit, Hülya | Hazer, Baki | Arslan, Hülya | Noda, Isao

Article | 2009 | Journal of Applied Polymer Science111 ( 5 ) , pp.2308 - 2317

A new and promising method for the diversification of microbial polyesters based on chemical modifications is introduced. Poly(3-hydroxy alkanoate)-g-(poly(tetrahydrofuran)-b-poly(methyl methacrylate)) (PHAg-(PTHF-b-PMMA)) multigraft copolymers were synthesized by the combination of cationic and free radical polymerization. PHA-g-PTHF graft copolymer was obtained by the cationic polymerization of THF initiated by the carbonium cations generated from the chlorinated PHAs, poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) in the presence of AgSbF 6. Therefore, PHA-g-PTHF gr . . .aft copolymers with hydroxyl ends were produced. In the presence of Ce +4 salt, these hydroxyl ends of the graft copolymer can initiate the redox polymerization of MMA to obtain PHA-g-(PTHF-b-PMMA) multigraft copolymer. Polymers obtained were purified by fractional precipitation. In this manner, their ?-values (volume ratio of nonsolvent to the solvent) were also determined. Their molecular weights were determined by GPC technique. The structures were elucidated using 1H-NMR and FTIR spectroscopy. Thermal analyses of the products were carried out using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 2308-2317, 2009 Daha fazlası Daha az

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

Allı, Sema | Allı, Abdulkadir | Hazer, Baki

Article | 2012 | Journal of Applied Polymer Science124 ( 1 ) , pp.536 - 548

Macromonomer initiators behave as macro cross-linkers, macro initiators, and macromonomers to obtain branched and cross-linked block/graft copolymers. A series of new macromonomer initiators for atom transfer radical polymerization (MIM-ATRP) based on polyethylene glycol (M n = 495D, 2203D, and 4203D) (PEG) were synthesized by the reaction of the hydroxyl end of mono-methacryloyl polyethylene glycol with 2-bromo propanoyl chloride, leading to methacryloyl polyethylene glycol 2-bromo propanoyl ester. Poly (ethylene glycol) functionalized with methacrylate at one end was reacted with 2-bromopropionyl chloride to form a macromonomeric . . .initiator for ATRP. ATRP was found to be a more controllable polymerization method than conventional free radical polymerization in view of fewer cross-linked polymers and highly branched polymers produced from macromonomer initiators as well. In another scenario, ATRP of N-isopropylacrylamide (NIPAM) was initiated by MIM-ATRP to obtain PEG-b-PNIPAM branched block/graft copolymers. Thermal analysis, FTIR, 1H NMR, TEM, and SEM techniques were used in the characterization of the products. They had a thermo-responsive character and exhibited volume phase transition at â 36°C. A plasticizer effect of PEG in graft copolymers was also observed, indicating a lower glass transition temperature than that of pure PNIPAM. Homo and copolymerization kinetics were also evaluated. © 2011 Wiley Periodicals, Inc Daha fazlası Daha az

Hyršl, Pavel | Büyükgüzel, Ender | Büyükgüzel, Kemal

Article | 2007 | Archives of Insect Biochemistry and Physiology66 ( 1 ) , pp.23 - 31

Larvae of the wax moth, Galleria mellonella (L.), were reared from first instar on a diet supplemented with 156, 620, 1,250, or 2,500 ppm boric acid (BA). The content of malondialdehyde (MDA, an oxidative stress indicator), and activities of the antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GPx)] were determined in the fat body and hemolymph in the 7th instar larvae and newly emerged pupae. Relative to control larvae, MDA was significantly increased in larval hemolymph, larval and pupal fat body, but decreased in the pupal hemolymph. Insects reared on di . . .ets with 156-and 620-ppm BA doses yielded increased SOD activity but 1,250- and 2,500-ppm doses resulted in decreased SOD activity in larval hemolymph. SOD activity was significantly increased but CAT was decreased in the larval fat body. High dietary BA treatments led to significantly decreased GST activity. However, they increased GPx activity in larval hemolymph. Dietary BA also affected larval survival. The 1,250- and 2,500-ppm concentrations led to significantly increased larval and pupal mortality and prolonged development. In contrast, the lowest BA concentration increased longevity and shortened development. We infer that BA toxicity is related, at least in part, to oxidative stress management. © 2007 Wiley-Liss, Inc Daha fazlası Daha az

Büyükgüzel, Ender | Büyükgüzel, Kemal | Erdem, Meltem | Adamski, Zbigniew | Adamski, Zbigniew | Marciniak, Pawel | Ziemnicki, Kazimierz

Article | 2013 | Archives of Insect Biochemistry and Physiology83 ( 1 ) , pp.15 - 24

Plant allelochemicals are nonnutritional chemicals that interfere with the biology of herbivores. We posed the hypothesis that ingestion of a glycoalkaloid allelochemical, ?-solanine, impairs biological parameters of greater wax moths Galleria mellonella. To test this idea, we reared wax moths on artificial diets with 0.015, 0.15, or 1.5 mg/100 g diet of ?-solanine. Addition of ?-solanine to the diet affected survival of seventh-instar larvae, pupae, and adults; and female fecundity and fertility. The diet containing the highest ?-solanine concentration led to decreased survivorship, fecundity, and fertility. The diets supplemented . . .with ?-solanine led to increased malondialdehyde and protein carbonyl contents in midgut and fat body and the effect was dose-dependent. Dietary ?-solanine led to increased midgut glutathione S-transferase activity and to decreased fat body glutathione S-transferase activitiy. We infer from these findings that ?-solanine influences life history parameters and antioxidative enzyme activities in the midgut and fat body of G. mellonella. © 2013 Wiley Periodicals, Inc Daha fazlası Daha az

Allı, Abdulkadir | Allı, Sema | Becer, C. Remzi | Hazer, Baki

Article | 2016 | European Journal of Lipid Science and Technology118 ( 2 ) , pp.279 - 287

Polymeric linoleic asit graft copolymers were synthesized via a nitroxide-mediated radical polymerization (NMRP) method in the presence of 2,2-6,6-tetramethylpiperidinyl-1-oxy (TEMPO). For this purpose, PLina-ox was exposed to polymerization with styrene (Sty) or Sty and pentafluorostyrene (F5Sty) in the presence of TEMPO by NMRP method in order to obtain PLina-g-PSty and PLina-g-PF5Sty-g-PSty graft copolymers with controlled structure and low polydispersity. Chain extension study was evaluated. Principal parameters, such as monomer concentration, initiator concentration, and polymerization time, which effect the polymerization reac . . .tions, were evaluated. The products thus obtained were well characterized by 1H NMR, GPC, and 19F NMR measurements. Practical application: We report for the first time the synthesis of PLina-g-PSty and PLina-g-PSty-g-PF5Sty graft copolymers in the presence of TEMPO. NMRP reactions were performed in the presence of TEMPO in order to obtain graft copolymers with controlled molecular weight and polydispersity. Chain-extension reactions were also successfully carried out because of the activation of TEMPO terminated chain ends of graft copolymers. Pure linoleic acid was auto-oxidized under daylight and air oxygen, yielding peroxidized PLina (PLina-ox). PLina-ox has been used in the polymerization of styrene (Sty) or copolymerization of Sty and pentafluorostyrene (F5Sty). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Daha fazlası Daha az

Kılıç, Muhammet Samet | Korkut, Şeyda | Hazer, Baki

Article | 2017 | Electroanalysis29 ( 10 ) , pp.2377 - 2384

Newly synthesized poly(styrene-g-oleic amide) was coated onto a rhodium nanoparticle modified glassy carbon (GC) surface for the fabrication of horseradish peroxidase based biosensor used for hydrogen peroxide detection. The rhodium modifed electrode presented ten times higher signal than unmodified electrode even at low elecrtroactive enzyme quantity by enhancing the electron transfer rate at the applied potential of -0.65 V. The biosensor designed by under the optimized rhodium electrodeposition time exhibited a fast response less than 5 s, an excellent operational stability with a relative standard deviation of 0.6 % (n=6), an ac . . .curacy of 96 % and a large linear range between 50 µM and 120 mM for hydrogen peroxide. Detection limit and the sensitivity parameters were calculated to be 44 µM and 57 µA mM-1 cm-2, respectively by preserving its entire initial response up to the 15 days, while only 20 % of its initial response was lost at the end of one month. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei Daha fazlası Daha az