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Öğe Apricot sulfurization: An occupation that induces an asthma-like syndrome in agricultural environments(Wiley, 2003) Koksal, N; Hasanoglu, HC; Gokirmak, M; Yildirim, Z; Gultek, ABackground Several cases of bronchial asthma have been presenting with acute attacks during the seasons of apricot sulfurization. The aim of this study was to reveal the effects of sulfur dioxide (SO2) exposure on the airways of the workers involved in this process. Methods SO2 levels in air were measured on 15 apricot farms, while the symptom scores of 69 workers were recorded before, during, and after SO2 exposure. Physical examination and pulmonary function tests (PFT) of the workers were also done prior to and after exposure periods. Results The measured SO2 concentrations ranged between 106.6 and 721.0 ppm. Dyspnea (80%), cough (78%), and eye and nose irritation (83-70%) were the most commonly observed symptoms. The workers had significant decreases in pulmonary functions after SO2 exposure. Decrements in FEV1, FEV1/FVC%, and FEF25-75% showed that the acute effect of SO2 on pulmonary functions of the workers was mostly of obstructive pattern. Conclusions Acute exposure to SO2 induces asthma-like syndrome (ALS) in apricot sulfurization workers. SO2 which has not been previously reported in agricultural environments as a cause of ALS may be considered as a new agent. (C) 2003 Wiley-Liss, Inc.(dagger).Öğe Caffeic acid phenethyl ester to inhibit posterior capsule opacification in rabbits(Elsevier Science Inc, 1997) Hepsen, IF; Bayramlar, H; Gultek, A; Ozen, S; Tilgen, F; Evereklioglu, CPurpose: To assess whether caffeic acid phenethyl ester (CAPE) prevents posterior capsule opacification (PCO) by suppressing the transformation of the lens epithelial cells. Setting: Departments of Ophthalmology, Chemistry, and Pathology, Turgut Ozal Medical Center, University of Inonu, Malatya, Turkey. Methods: Twenty pigmented island rabbits having phacoemulsification in their right eyes were randomized into two groups. In Group 1, 10 mu g/ml of CAPE was added to the anterior chamber irrigating solution and a 1% solution of CAPE was injected subconjunctivally for 3 weeks postoperatively. The irrigating solution in Group 2 (control) did not include CAPE. The development of PCO was assessed weekly and its density was graded by slitlamp biomicroscopy. Histologic analysis was performed 3 months after surgery. Results: Group I had clear capsules or minor PCO. Group 2 developed more severe PCO or complete opacification. The difference between the two groups was statistically significant (P = .04). Conclusion: These preliminary results indicate that CAPE is effective in suppressing PCO in pigmented rabbits and may be beneficial in clinical use in humans because it has no documented harmful effects on normal cells.Öğe Preparation and characterization of a clay-polyvinylpyridinium matrix for the removal of bacterial cells from water(Chapman Hall Ltd, 1997) Seckin, T; Onal, Y; Yesilada, O; Gultek, APolyvinylpyridinium salts were immobilized onto a clay matrix and were then tested for their antibacterial properties. The clay-polyvinylpyridinium matrix was prepared by the copolymerization of gamma-methacryloxypropyltriethoxy silane bonded covalently to clay and 4-vinylpyridine and subsequent quaternization with benzyl halides. Suspension tests for antibacterial properties of the immobilized bactericide against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa demonstrated the high activity of the pyridinium salts that are bonded to the polyacrylate spacer. Advantageously, these insoluble clay-polymer bactericides could be applied without any contamination by the substrate.Öğe Preparation and phenol captivating properties of polyvinylpyrrolidone-montmorillonite hybrid materials(Wiley, 2001) Gultek, A; Seckin, T; Onal, Y; Icduygu, MGMontmorillonite minerals were modified in two distinct steps in order to remove hydroxlated toxicants from the aqueous environment. At first, the montmorillonite minerals were acrylated with the silylating agent gamma -methcaryloxypropyl trimethoxysilane to give a product denoted as TAY-10. In the second step these materials readily reacted with vinylpyrrolidone to form copolymers covalently bonded to the clay. All hybrid materials were characterized by FTIR spectroscopy, thermogravimetry, X-ray diffractometry, SEM, and differential thermal analysis. The original montmorillonite structure was maintained for the copolymer modified surfaces. Different loadings of polyvinylpyrrolidone (PVP) were examined to arrive at the optimal conditions for the removal of toxicants from the aqueous environment. The presence of the PVP enhanced the adsorption capacity of the clay toward phenolic compounds from solution as evidenced by the retention percent that was as high as 98.9%. These results demonstrated the feasibility of utilizing a PVP modified clay as a thermally recyclable adsorbent for environmental pollutants. (C) 2001 John Wiley & Sons, Inc.Öğe Synthesis, characterization and thermal properties of bentonite-polyacrylate sol-gel materials(Royal Soc Chemistry, 1997) Seckin, T; Gultek, A; Onal, Y; Yakinci, ME; Aksoy, IA new type of material incorporating bentonite with an alkoxide, H2C=C(CH3)COO(CH2)(3)Si(OCH3)(3), has been prepared successfully using a sol-gel process. The structures and structural changes upon heating, of the bentonite and the sol-gel material. were investigated by FTIR, XRD and DSC. Using the metal alkoxide and the corresponding clay mineral as precursors, the additive reaction followed by free radical polymerization resulted in a novel material in which polymer was attached covalently to, silicate sheets of bentonite via hydroxy bonding.
