Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 53Citation - Scopus: 60Properties of N-Eicosane Silk Fibroin-Chitosan Microcapsules(John Wiley and Sons Inc., 2011) Başal, Güldemet; Şirin Deveci, Senem; Yalçın, Dilek; Bayraktar, OğuzPCM microcapsules containing n-eicosane were prepared by complex coacervation of silk fibroin (SF) and chitosan (CHI). Chemical characterization of microcapsules was carried out using Fourier-transform infrared (FT-IR) spectroscopy. Thermal properties and thermal stability of microencapsulated n-eicosane were determined by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). FTIR spectra confirmed the encapsulation of n-eicosane within the microcapsules. Results from thermal analyses showed that microcapsules consisted of an average of 45.7 wt % n-eicosane, and had a thermal energy storage and release capacity of about 93.04 J/g and 89.68 J/g, respectively.Article Citation - WoS: 19Citation - Scopus: 23Inhibition of Catechol-O (comt) by Some Plant-Derived Alkaloids and Phenolics(Elsevier Ltd., 2010) Yalçın, Dilek; Bayraktar, OğuzIn this study, as an alternative to the medicines, natural compounds extracted from plant species (Peganum harmala, Cistus parviflorus and Vitex agnus-cactus) were investigated in order to inhibit the catechol-O-metyhltranferase (COMT) activity. In fluorometric enzyme assay, S-adenosylmethionine (SAM) and aesculetin (ES) were used as methyl donor and acceptor substrates, respectively. Their Km values were determined as 3.5 ± 0.3 μM and 6.4 ± 0.4 μM in absence of inhibitor. Inhibition performances of the plant-derived polyphenolics and alkaloids were determined. Inhibitory effect of alkaloids extracted from P. harmala seeds was found the highest among the plant extracts; however, it was lower than that of 3,5-DNC. In case of inhibition mechanism, mixed type inhibition was observed for alkaloid extract whereas uncompetitive inhibition was observed for 3,5-DNC. In case of polyphenolic extracts obtained from C. parviflorus and V. agnus-cactus leaves, mechanism were also explained as mixed type inhibition and their αKi values were calculated as 1.99 ± 0.35 μg/ml and 9.48 ± 0.58 μg/ml, respectively. © 2009 Elsevier B.V. All rights reserved.Article Citation - WoS: 32Citation - Scopus: 33Characterization of Silk Fibroin/Hyaluronic Acid Polyelectrolyte Complex (pec) Films(Springer Verlag, 2008) Malay, Özge; Yalçın, Dilek; Batıgün, Ayşegül; Bayraktar, OğuzThis study aimed the characterization of the films casted from the aqueous mixtures of the pH induced complexes between silk fibroin (SF) and hyaluronic acid (HA). The insoluble and transparent films were subjected to scanning electron microscopy (SEM) analyses to show the morphological changes. Thermal analysis of complex films was determined by a differential scanning calorimeter (DSC). The changes in the crystalline state were monitored by X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). It was shown that the complexation between HA and SF was dominantly induced by pH. It was shown that the complex films comprised mixtures of crystalline and non-crystalline regions.Article Citation - WoS: 42Citation - Scopus: 46Characterization and Recovery of Tartaric Acid From Wastes of Wine and Grape Juice Industries(Springer Verlag, 2008) Yalçın, Dilek; Özçalık, Onur; Altıok, Evren; Bayraktar, OğuzTartaric acid is mainly used in food, pharmaceuticals and cosmetics industries. In this study, the waste samples, which contain tartaric acid, from the wastes of wine and grape juice industries were characterized by using TG, DSC, FTIR and XRD techniques. HPLC was used to determine tartaric acid content of samples. The decomposition temperatures of waste samples were found to be relatively higher compared with that of pure tartaric acid. This difference in decomposition temperatures was attributed to the presence of potassium tartrate since high potassium content was detected with ICP-AES.