Oven dried cut stigmas of Crocus sativus L. cultivated in Eskisehir and Safranbolu regions of Turkey were subjected to micro distillation to extract steam volatiles. They were then analysed by Gas Chromatography and Gas Chromatography/Mass Spectrometry, simultaneously. The colour compounds were extracted with 80% methanol and analysed by High Pressure Liquid Chromatography HPLC/DAD and HPLC/MS/MS. The activities of the extracts of saffron against 2,2ʹ-azinobis-3-ethylbenzothiazoline-6-sulphonic acid free radical (ABTS •+ ) were investigated using on-line (HPLC-ABTS•+ ) and off-line methods. Safranal (62.1 and 49.3%) and α-isophorone (10.0 and 16.3%) were found as the characteristic aromatic volatiles in the Eskisehir and Safranbolu samples, respectively. Crude saffron extracts showed high total antioxidant activity against ABTS•+ radical.ARTICLE HISTORY

Article InfoThe aim of this study is to develop a valid and reliable instrument which is enable to assess pre-service teachers' self-directed learning skills. 140 students included in this study for validity and reliability. Exploratory and confirmatory factor analyses were adopted, and item analysis was used. Cronbach's alpha reliability coefficient was calculated. At the end of study, a scale with 25 items (α=0.85), explains 56.997% of the total variance, was developed. Confirmatory Factor analysis indicated that four items do not related to the overall items and they removed from the scale and scale was finalized with 21 items. According to the result of factor analysis of scale, two factors were determined. These factors was named as "self-efficacy" (10 items, α=0.74), and "awareness" (11 items; α=0.84).

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Ab initio calculations are performed for the calix[4]arene (1) and its derivatives (2 and 3), in this study. 1 H and 13 C NMR measured spectral data given in our previous work are used to elucidate the structures of the prepared calix[4]arenes (1-3). The molecular geometry and chemical shift are calculated by using ab initio calculations based on the Hartree-Fock (HF) and the density functional theory (DFT) in the ground state. The results obtained from both methods are in agreement with the experimental results. The results of molecular geometry and chemical shifts show that DFT approach is closer to the experimental data than HF method.

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