WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 8Citation - Scopus: 10Use of Magic Sandwich Echo and Fast Field Cycling Nmr Relaxometry on Honey Adulteration With Corn Syrup(John Wiley and Sons Inc., 2021) Berk, Berkay; Çavdaroğlu, Çağrı; Grunin, Leonid; Ardelean, Ioan; Kruk, Danuta; Mazı, Bekir G.; Öztop, Halil Mecitconventional time domain nuclear magnetic resonance (TD-NMR) pulse sequence: magic sandwich echo (MSE) was used to detect the adulteration of honey by glucose syrup (GS) and high fructose corn syrup (HFCS) accompanied with T-1 and T-2 relaxation times. Also, fast field cycling NMR (FFC-NMR) relaxometry and multivariate analysis were performed to investigate the adulteration. RESULTS Higher maltose in GS and changing glucose to water ratio of HFCS gave high correlation with the crystal content values. In HFCS adulteration, two separate populations of protons having different T-2 values were detected and T-1 times were also used to determine GS adulteration. Addition of GS increased T-1 while addition of HFCS increased T-2, significantly. CONCLUSION The results showed that it is possible to differentiate the unadulterated and adulterated honey samples by using TD-NMR relaxation times and crystal content values obtained by the MSE sequence. By FFC-NMR relaxometry, not only GS addition but also the amount of GS was examined. The multivariate analysis technique of principal component analysis was able to distinguish the types of adulterants.Article Citation - WoS: 12Citation - Scopus: 15Probabilistic Investigation of Error Propagation in Frequency Domain Decomposition-Based Operational Modal Analysis(John Wiley and Sons Inc., 2021) Hızal, Çağlayan; Aktaş, EnginEach operational modal analysis (OMA) technique may produce significant errors during the identification procedure due to the applied methodology, environmental/operational conditions, and instrumentation. Consequently, those errors can adversely affect the quality of identified parameters. In this context, this study aims at providing a comprehensive discussion on the propagation of predictions errors in the frequency domain OMA. To mitigate the prediction errors those considered to be induced by modeling and measurement errors, an extended formulation is presented based on a recently developed Modified Frequency and Spatial Domain Decomposition technique. A comprehensive investigation is presented for the probabilistic modeling of output power spectral density (PSD), considering prediction errors. Numerical and real data applications are conducted to show the effectiveness of the proposed methodology.Article Citation - WoS: 13Citation - Scopus: 13Authentication of Turkish Olive Oils by Using Detailed Pigment Profile and Spectroscopic Techniques(John Wiley and Sons Inc., 2020) Uncu, Oğuz; Uncu, Oğuz; Özen, Banu; Özen, Fatma Banu; Tokatlı, Figen; Tokatlı, FigenBACKGROUND Minor compounds of olive oil could have discriminatory characteristics in the authentication of this product. It was aimed to determine the detailed pigment profiles of Turkish olive oils and use them in differentiation of the samples in comparison to fast, reliable, and environmentally friendly Fourier-transform infrared (FTIR) and ultraviolet (UV)-visible spectroscopic techniques. Pigment contents of 91 olive oils obtained from different locations for two consecutive harvesting years were determined with chromatographic analysis and FTIR and UV-visible spectra of these samples were also obtained. All data were analyzed with orthogonal partial least-squares discriminant analysis to investigate the differentiation ability of these methods with regard to their detailed pigment and spectroscopic profiles. RESULTS Pheophytin a (2.78-8.98 mg kg(-1)) and lutein (1.19-4.07 mg kg(-1)) were the major pigments in all samples. Pigment profiles provided successful classification of olive oils with respect to their designated origins and harvesting year with average correct classification rates of 97%. UV-visible spectroscopy has quite similar results with pigment profiles in terms of its discriminatory power. In addition, FTIR and fused data were slightly better in discrimination of the samples, and the fused dataset has the highest correct classification rate of 100%. CONCLUSION Use of detailed pigment profiles is quite promising in authentication of olive oils. However, UV-visible and FTIR spectroscopic techniques could be reliable alternatives for the same purposes. All of the techniques studied have great potential in 'protected designation of origin' certification studies. (c) 2020 Society of Chemical IndustryArticle Citation - WoS: 6Citation - Scopus: 8Outer-Membrane Protease (ompt) Based E.coli Sensing With Anionic Polythiophene and Unlabeled Peptide Substrate(John Wiley and Sons Inc., 2020) Sinsinbar, Gaurav; Gudlur, Sushanth; Wood, Sarah E.; Ammanath, Gopal; Yıldız, Ümit Hakan; Alagappan, Palaniappan; Liedberg, BoE. coli and Salmonella are two of the most common bacterial pathogens involved in foodborne and waterborne related deaths. Hence, it is critical to develop rapid and sensitive detection strategies for near-outbreak applications. Reported is a simple and specific assay to detect as low as 1 CFU mL(-1)of E. coli in water within 6 hours by targeting the bacteria's surface protease activity. The assay relies on polythiophene acetic acid (PTAA) as an optical reporter and a short unlabeled peptide (LL37(FRRV)) previously optimized as a substrate for OmpT, an outer-membrane protease on E. coli. LL37(FRRV)interacts with PTAA to enhance its fluorescence while also inducing the formation of a helical PTAA-LL37(FRRV)construct, as confirmed by circular dichroism. However, in the presence of E. coli LL37(FRRV)is cleaved and can no longer affect the conformations and optical properties of PTAA. This ability to distinguish between an intact and cleaved peptide was investigated in detail using LL37(FRRV)sequence variants.Article Citation - WoS: 28Citation - Scopus: 33Rapid Detection of Green-Pea Adulteration in Pistachio Nuts Using Raman Spectroscopy and Chemometrics(John Wiley and Sons Inc., 2021) Taylan, Osman; Çebi, Nur; Yılmaz, Mustafa Tahsin; Sağdıç, Osman; Özdemir, Durmuş; Balubaid, MohammedBACKGROUND Ground pistachio nut is prone to adulteration because of its high economic value and wide usage. Green pea is known as the main adulterant in frauds involving pistachio nuts. The present study developed a new, rapid, reliable and low-cost methodology by using a portable Raman spectrometer in combination with chemometrics for the detection of green pea in pistachio nuts. RESULTS Three different methods of Raman spectroscopy-based chemometrics analysis were developed for the determination of green-pea adulteration in pistachio nuts. The first method involved the development of hierarchical cluster analysis (HCA) and principal component analysis (PCA), which differentiated authentic pistachio nuts from green pea and green pea-adulterated samples. The best classification pattern was observed in the adulteration range of 20-80% (w/w). In addition to classification methods, partial least squares regression (PLSR) and genetic algorithm-based inverse least squares (GILS) were also used to develop multivariate calibration models to determine quantitatively the degree of green-pea adulteration in grounded pistachio nuts. The spectral range of 1790-283 cm(-1)was used in the case of multivariate data analysis. A green-pea adulteration level of 5-80% (w/w) was successfully identified by PLSR and GILS. The correlation coefficient of determination (R-2) was determined as 0.91 and 0.94 for the PLSR and GILS analyses, respectively. CONCLUSION A Raman spectrometer combined with chemometrics has a high capability with regard to the detection of adulteration in pistachio nuts, combined with low cost, strong reliability, a high level of accuracy, rapidity of analysis, and minimum sample preparation.Conference Object Antimicrobial Activity of Essential Oils Against H. Pylori(John Wiley and Sons Inc., 2010) Altıok, Duygu; Bekmen, N.; Demiray Gürbüz, Ebru; Tıhmınlıoğlu, Funda; Yılmaz, Özlem[No abstract available]Conference Object A Natural Antioxidant: Trans-Resveratrol Against H. Pylori(John Wiley and Sons Inc., 2010) Altıok, Duygu; Demiray Gürbüz, Ebru; Bekmen, N.; Tıhmınlıoğlu, Funda; Yılmaz, Özlem[No abstract available]Conference Object Genipin Crosslinked Clarithromycin Loaded Chitosan Microspheres for Eradication of Helicobacter Pylori(John Wiley and Sons Inc., 2011) Altıok, Duygu; Demiray Gürbüz, Ebru; Bekmen, N.; Yılmaz, Özlem; Tıhmınlıoğlu, Funda[No abstract available]Conference Object Genotypic and Phenotypic Muscle-Bone Interactions During Unloading/Reloading(John Wiley and Sons Inc., 2013) Judex, Stefan; Zhang, Weidong; Donahue, Leah Rae; Özçivici, Engin[No abstract available]Conference Object Mesenchymal Stem Cells Administered Intraperitoneally Have a Potent Effects on the Experimental Allergic Airway Disease(John Wiley and Sons Inc., 2015) Işık, S.; Adan, Aysun; Karaman, M.; Kiray, M.; Bağrıyanık, H. A.; Çağlayan-Sözmen, S.; Uzuner, N.; Baran, Yusuf[No abstract available]