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Assessment of Phenolic Acid Content and In Vitro Antiradical Characteristics of Hawthorn
Nilgün Öztürk,Muzaffer Tunçel 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.6
The infusions and extracts obtained from leaves with flowers, fruit peel, and seed from hawthorn (Crataegus monogyna Jacq., Family Rosaceae) were subjected to evaluation as potential sources of antioxidant phytochemicals on the basis of their total content of phenolics, levels of phenolic acids, and in vitro antiradical activity. Total phenolic content of extracts was determined using the modified Folin–Ciocalteau method. Antioxidant activity was determined for phenolic extracts by a method involving the use of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Phenolic acids containing extracts and infusions from hawthorn leaves, fruit peel, and seeds were obtained using different polarity solvents and separated by reverse-phase high-performance liquid chromatography, which enabled improved separation by the use of a C18 column, an acidic mobile phase, and gradient elusion. The highest total phenolic content (343.54 mg of gallic acid equivalents/g) and the highest DPPH radical scavenging activity as the inhibition percentage (60.36%) were obtained in ethyl acetate extract from hawthorn leaves with flower. Also, the highest phenolic acid content was measured in the extracts of hawthorn leaves with flowers: protocathechuic (108–128 mg/100 g), p-hydroxy benzoic (141–468 mg/100 g), caffeic (137–3,580 mg/100 g), chlorogenic (925–4,637 mg/100 g), ferulic (3,363–3,462 mg/100 g), vanillic (214 mg/100 g), and syringic (126 mg/100 g) acids. The results indicate that hawthorn is a promising plant because of its high antioxidant activity.
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Caner Kılıç,Ümit Tunçel,Metin Kaya,Ela Cömert,Samet Özlügedik 대한이비인후과학회 2017 Clinical and Experimental Otorhinolaryngology Vol.10 No.4
Objectives. The aim of this study was to compare the effect of the presence of one or two arytenoids on early/late period swallowing-aspiration functions. Methods. Supracricoid partial laryngectomy (SCPL) with the diagnosis of laryngeal cancer between 2012 and 2014 were retrospectively evaluated. The patients were categorized into two groups as follows: group I, patients who underwent SCPL with one arytenoid cartilage and group II, patients who underwent SCPL with two arytenoid cartilages. The time of decannulation and oral feeding onset, and swallowing-aspiration functions were evaluated and compared in the early nutritional period, first, and third months. Results. There was no significant correlation between decannulation time and swallowing-aspiration. The aspiration rates in group I and group II were similar and there was no significant difference in oral feeding onset and aspiration grades in the first and third months between both groups. Conclusion. We found similar oncological and functional outcomes in SCPL which protected one or two arytenoid cartilages. Therefore we suggest to be performed one arytenoid cartilage SCPL in selected patients who was advance stage and tumor volume over with larynx cancer.
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Tuba Demirel,Md. Mahbubor Rahman,Kemal Şahin Tunçel,Ismail Karacan 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11
Thermal-oxidative stabilization of polyacrylonitrile (PAN) fiber pretreated with ammonium bromide (NH4Br) wasperformed in the air atmosphere at temperatures between 200 and 250 °C for periods of 5 to 75 min in a multistep approach. The study demonstrates that the NH4Br incorporation is highly effective in accelerating nitrile group cyclization by reducingthe time required to form a thermally stable structure. After 60 min of the multistep stabilization, NH4Br incorporated andstabilized PAN was entirely thermally stable, infusible, and non-burning. XRD analysis showed the conversion of the pristinePAN molecular structure from a laterally ordered condition to a very disordered amorphous structure by crosslinking andaromatization process. Infrared analysis indicated rapid and concurrent aromatization and dehydrogenation reactions assistedby the formation of oxygen-containing functional groups. With the progression of the stabilization period, TGA thermogramsrevealed a comparative increase in thermal stability, as directed by the continuous rise of carbon yield. By decreasing therequired time for the stabilization process of PAN fiber, the use of NH4Br impregnation is expected to enhance carbon fiberproductivity at a reduced cost considerably.
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Hong, Sung-Pil,Tunç,el, Levent Elsevier 2008 Discrete Applied Mathematics Vol.156 No.1
<P><B>Abstract</B></P><P>We present a unifying framework to establish a lower bound on the number of semidefinite-programming-based lift-and-project iterations (rank) for computing the convex hull of the feasible solutions of various combinatorial optimization problems. This framework is based on the maps which are commutative with the lift-and-project operators. Some special commutative maps were originally observed by Lovász and Schrijver and have been used usually implicitly in the previous lower-bound analyses. In this paper, we formalize the lift-and-project commutative maps and propose a general framework for lower-bound analysis, in which we can recapture many of the previous lower-bound results on the lift-and-project ranks.</P>
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