Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - Scopus: 1Characteristics and Production Technologies of Byzantine Building Bricks From the Anaia Church in Western Anatolia(Springer, 2023) Çam, Elif; Uğurlu Sağın, ElifFired bricks were valued as essential building materials in the central tradition of Byzantine architecture in Constantinople (Istanbul), Anatolia, and the Balkans. In this study, Byzantine bricks from three construction periods, covering nearly nine centuries (fifth-fourteenth centuries), of Anaia Church (Kadikalesi) in Western Anatolia were investigated to determine their characteristics, raw material properties, and production technologies. The characteristics of the bricks were evaluated and compared in order to identify similarities and differences between the periods and to investigate the continuity of the tradition of brick production over centuries. Basic physical and colorimetric properties, chemical and mineralogical compositions, thermal behavior, and microstructural and mechanical properties of bricks were determined by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (SEM-EDS), Fourier-transform infrared spectrometry (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and mechanical tests. The results indicated that all the bricks in the Anaia Church were brown-beige colored, highly porous, low-density materials with low mechanical strength. They were produced from Ca-rich clays, probably obtained from two different sources used during all construction periods. The mineralogical composition and thermal properties revealed that the bricks from the first and second periods were fired at between 800 and 900 & DEG;C and the bricks from the third period were fired at < 850 & DEG;C. Greater calcium content and firing temperatures were found to reduce the total porosity and the number of small pores (< 10 & mu;m) and increase the mechanical strength of the bricks. The results of the study revealed no significant differences in the production of bricks, including raw material sources and kiln conditions, for the different construction periods of the church.Article Citation - WoS: 17Citation - Scopus: 22Protein Corona Formation on Silver Nanoparticles Under Different Conditions(Elsevier, 2022) Tomak, Aysel; Yılancıoğlu, Buket; Winkler, David; Öksel Karakuş, CeydaThe surfaces of nanoparticles become covered by biomolecules in biological fluids. This protein ‘corona’ modifies materials’ characteristics and biological activity. The composition of the protein corona is dynamic, abundant biomolecules that bind first are subsequently replaced by less abundant but more tightly bound ones. Here, we explore the formation of the silver nanoparticle protein corona on exposure to cell culture media containing 10 % fetal bovine serum supplemented Dulbecco's Modified Eagle's medium. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis and liquid chromatography-mass spectrometry/mass spectrometry analysis were used to monitor how different parameters such as incubation time, heating duration, cell culture medium, incubation temperature, and the number of washes affect the nanoparticle–protein corona complex. silver nanoparticles with and without bound proteins were characterized by electron microscopy, dynamic light scattering, and ultraviolet-visible-near-IR spectroscopy. The tetrazolium-based MTT assay was used to determine viability of A549 human lung adenocarcinoma cells treated with silver nanoparticles. Characterization of the nanoparticles before and after protein binding provided insights into their changing morphology on corona formation. Our results confirmed that the physiological environment directly affects protein corona formation on nanoparticle surfaces. In particular, incubation condition-dependent differences in the amount of bound proteins were observed. This work highlights the importance of environmental drivers of protein adsorption, which should be considered when predicting and/or controlling protein targets of silver nanoparticles.Article Citation - WoS: 23Citation - Scopus: 28Classification of Turkish Monocultivar (ayvalık and Memecik Cv.) Virgin Olive Oils From North and South Zones of Aegean Region Based on Their Triacyglycerol Profiles(John Wiley and Sons Inc., 2013) Gökçebag, Mümtaz; Dıraman, Harun; Özdemir, DurmuşIn this study, a total of 22 domestic monocultivar (AyvalIk and Memecik cv.) virgin olive oil samples taken from various locations of the Aegean region, the main olive growing zone of Turkey, during two (2001-2002) crop years were classified and characterized by well-known chemometric methods (principal component analysis [PCA] and hierarchical cluster analysis [HCA]) on the basis of their triacylglycerol (TAG) components. The analyses of TAG components (LLL and major fractions LOO, OOO, POO, PLO, SOO, and ECN 42-ECN 50) in the oil samples were carried out according to the HPLC method described in a European Union Commission (EUC) regulation. In all analyzed samples the value of trilinolein (LLL), the least abundant TAG, did not exceed the maximum limit of 0.5 % given by the EUC regulation for different olive oil grades. The ranges of abundant TAG, namely LOO, OOO, POO, PLO, and SOO, were 13.30-16.08, 37.27-46.36, 21.39-23.24, 4.93-7.03, and 4.72-6.00 %. The TAG data of Aegean virgin olive oils were similar to those of products from important olive-oil-producing Mediterranean countries was determined. Also, the estimation of major fatty acids (FA) was carried out by using a formula based on TAG data. The PCA results showed that some TAG components have an important role in the characterization and geographical classification of 22 monocultivar virgin olive oil. The Aegean virgin olive oil samples were successfully classified and discriminated into two main groups as the North and South (growing) subzones or AyvalIk and Memecik olives (cultivars) according to the HCA results based on experimental TAG data and calculated major FA profile.Article Citation - WoS: 13Citation - Scopus: 14Characterization and Dehydration Behavior of a Natural, Ammonium Hydroxide, and Thermally Treated Zeolitic Tuff(Taylor and Francis Ltd., 2011) Narin, Güler; Balköse, Devrim; Ülkü, SemraAqueous NH4OH-treated and subsequently calcined forms of local natural zeolitic tuff were characterized by different techniques including scanning electron microscopy (SEM), X-ray powder diffraction, inductively coupled plasma-atomic emission spectroscopy (ICP-AES), volumetric N2 adsorption at -196°C, thermogravimetry (TG), differential scanning calorimetry (DSC), and transmittance infrared spectroscopy. The dehydration behavior of the samples was investigated using an in situ temperature-programmed diffuse reflectance Fourier transform infrared spectroscopy (TP-DRIFTS) method under vacuum. The DRIFTS spectra recorded yielded information about the effect of the NH4OH treatment and subsequent calcination on the dehydration behavior of the natural zeolite.Changes in the infrared bands corresponding to vibrations of the O-H and N-H bonds upon in situ heating under vacuum were analyzed.Article Citation - WoS: 16Citation - Scopus: 14Isolation and Characterization of Bacillus Thuringiensis Strains From Olive-Related Habitats in Turkey(John Wiley and Sons Inc., 2008) Çınar, Çelenk; Apaydın, Özgür; Yenidünya, Ali Fazıl; Harsa, Hayriye Şebnem; Güneş, HaticeAims: To isolate Bacillus thuringiensis strains from different olive-related habitats (olive groves and olive oil factories) in Turkey and to characterize these strains by molecular methods. Methods and Results: A total of 150 samples, consisting of olive grove soil, green olive leaves, olive leaf residues, animal faeces, olive pomace and dust, were examined for the presence of B. thuringiensis. One hundred B. thuringiensis strains were isolated from 54 environmental samples (36%) and characterized in terms of crystal morphology, cry and cyt gene content by polymerase chain reaction, plasmid profiles and 16S-internal transcribed spacer ribosomal DNA restriction fragment length polymorphism (16S-ITS rDNA RFLP). The highest percentage of samples containing B. thuringiensis was found in 38 out of 54 total soil samples (70%). Of the 100 B. thuringiensis isolates, the most frequent crystal shapes were irregularly shaped (24%), spherical-irregular pointed (19%), cuboidal (17%) and spherical (16%). The cry1 plus cry4 genotype was the most abundant genotype in our collection (21%). RFLP analysis of the amplified 16S-ITS rDNA revealed 11 distinct patterns for the isolates and 10 reference strains. Conclusions: Bacillus thuringiensis isolates showed a great genetic diversity and crystal shape heterogeneity. Significance and Impact of the Study: This is the first study on the isolation and characterization of B. thuringiensis from olive-related habitats in Turkey. No correlation was observed between the cry genotypes and insecticidal crystal shapes of the isolates. Restriction profiles of 23% of the isolates were found to be different from those of the 10 reference strains used.Article Citation - WoS: 21Citation - Scopus: 29Partial Purification and Kinetic Characterization of Mushroom Stem Polyphenoloxidase and Determination of Its Storage Stability in Different Lyophilized Forms(Elsevier Ltd., 2007) Şimşek, Şebnem; Yemenicioğlu, AhmetMonophenolase (1011 ± 626 U/g AP) and diphenolase activities (5163 ± 3059 U/g AP) of PPO in acetone powders (APs) of different mushroom stems varied considerably. However, the limited variation of average dipenolase (L-DOPA) to monophenolase (L-tyrosine) activity ratio (5.4 ± 0.7) in crude extracts showed the homogeneity of PPO from different mushroom stems. The change in extraction material or partial purification method (ammonium sulfate or acetone precipitation) did not affect the temperature stability, temperature and pH dependency and Km of monophenolase activity considerably. However, some changes were observed in pH stability and substrate specificity of PPO in different parties of mushroom stems. The most important aspects of mushroom stem PPO are its lower diphenolase to monophenolase activity ratio than mushroom cap PPO, low temperature dependency of activity between 25 and 40 °C (Ea = 30 kJ/mol), broad optimum pH between 6 and 8, but lack of activity pH ≤5, and ability to use phloridzin as substrate. The mushroom stem PPOs partially purified and lyophilized by using sucrose, dextran or alginate showed moderate to high stability at -18 °C for 6-6.5 months. Thus, the mushroom stems obtained as a waste material during mushroom processing may be used as a more homogenous source than whole mushrooms to obtain PPO used for different industrial, clinical or research purposes.