Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Development of Chemometrics Method Based on Infrared Spectroscopy for the Determination of Cement Composition and Process Optimization [article](ACG Publications, 2022) Özdemir, Durmuş; Gümüş, Mehmet Gökhan; Tepeli, DilekIn combination with a multivariate calibration method, FTIR-ATR spectroscopy was presented as a rapid method for the determination of some major oxides (CaO, SiO2, Al2O3, Fe2O3) and minor oxides (MgO, SO4, Na2O, and K2O) in diverse materials (raw material, raw meal, additives, clinker, and types of cement) in cement manufacturing. The FTIR spectroscopy based multivariate models were generated by taking X-ray fluorescence (XRF) as a reference method. Among a number of spectral preprocessing methods, extended multiplicative scatter correction (EMSC) yielded the best PLS models. The standard error of prediction (SEP) for the optimal FTIR based PLS models ranged from 0.10 to 2.07 (w/w%), and the regression coefficient (R2) ranged from 0.95 to 0.99 for PLS predicted vs XRF reference plots. Statistical evaluation of the both methods was carried out by paired t-test at the 95% confidence level and the results showed that the FTIR-ATR combined with PLS model results are consistent with the XRF reference measurements for all the oxides studied. Compared to the XRF method, which can take anywhere from a few minutes to an hour for each measurement, the proposed method is faster, cheaper, and safer. The presented technology also allows rapid monitoring of a cement factory production line.Article Citation - WoS: 1Citation - Scopus: 2A Molecularly Imprinted Polymer as Solid Phase Extraction Sorbent for Ketoprofen Determination in Water and Artificial Serum Prior To Hplc(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2022) Shahwan, Talal; Gürel Özyurt, Elif; Özyurt, Ömer; Ölçer, Yekta Arya; Eroğlu, Ahmet Emin; Boyacı, EzelKetoprofen (KET) is an active pharmaceutical compound that has pain relieving and antipyretic effects. Its determination in body fluids and environmental waters is important due to widespread use of the compound. In this study, a selective and reliable method has been developed for the determination of ketoprofen in water and artificial serum using molecularly imprinted polymers (MIPs) as a solid phase extraction sorbent prior to HPLC-DAD detection. The MIP was synthesized by copolymerization of methacrylic acid (MAA) and trimethylpropane trimethacrylate (TRIM) in the presence of ketoprofen as the template. For the sake of comparison, nonimprinted polymer (NIP) was also synthesized under the same experimental conditions without the addition of ketoprofen under the same experimental conditions. Critical extraction parameters such as sample pH, shaking time and sorbent amount were optimized and adjusted to 8.0, 24 h, and 10.0 mg, respectively, for a sample volume of 10.0 mL. MIP showed higher selectivity than NIP towards ketoprofen in an artificial matrix containing another pain relieving drug, ibuprofen, and a cardiovascular drug, metoprolol. The proposed method was successfully applied for the detection of ketoprofen in spiked drinking water, tap water, and artificial serum samples, and showed satisfactory results with respective recoveries of 96.8 % (± 0.8), 93.7% (± 0.6), 62.2% (± 0.6), and 69.9% (± 0.6).Article Citation - WoS: 1Citation - Scopus: 1Comparative Proteomic Analysis of Bacillus Thuringiensis Wild-Type and Two Mutant Strains Disturbed in Polyphosphate Homeostasis(TUBITAK, 2018) Yeşilırmak, Filiz; Doruk, Tuğrul; Yılmaz, Şerif; Tunca Gedik, SedefPolyphosphate polymer (polyP) plays a very important role in every living cell. Synthesis of this linear polymer of phosphate (Pi) residues is catalyzed by the polyphosphate kinase (PPK) enzyme. It was shown that high levels of intracellular polyphosphate stimulated endotoxin production by Bacillus thuringiensis subsp. israelensis (Bti). In this study, proteomic analysis of the wild-type and two mutant strains, overexpressing the ppk gene (Bti pHTppk) and without the ppk gene (Bti ∆ppk), were used to clarify the relation between polyP and endotoxin production. Intracellular proteins were separated by two-dimensional gel electrophoresis; 41 spots of interest (proteins differentially expressed) were obtained and 35 of them were identified by mass spectrometry. Analysis of the protein profiles showed that there is a general decrease in the expression levels of proteins related with energy metabolism, amino acid metabolism, and purine biosynthesis in both Bti pHTppk and Bti ∆ppk. Gluconeogenesis and fatty acid metabolism were also slowed down in both strains, whereas expression of stress response proteins increased compared to the wild-type. These results suggested that changes in polyP concentration cause a general stress condition inside the cell, which in turn stimulates secondary metabolite synthesisArticle Reactions of the Solvent-Stabilized Compound [moocl2(thf)2] With Aromatic Nitrogen Donor Ligands: Spectroscopic Characterization and Semiempirical Am1* Calculations(TUBITAK, 2009) Kılıçkaya, Gülşah; Doğan, Başak; Acar, Nursel; Sözüer, Hikmet IşılReaction of the solvent-stabilized dioxo-molybdenum(VI) compound [MoO2 Cl2 (THF)2]withP Ph3 yielded the oxomolybdenum(IV) species [MoOCl2 (THF)2](1) by the removal of one oxygen atom as PPh3 O. The complexes [MoOCl2 (=NC6 H4 CN)] 2,[MoOCl2 (CNC6 H4 OH)] 3,[MoOCl2 (=NC6 H4 NH2)] 4,and [MoOCl2 (=NC6 H4 OCH3)] 5, were synthesized by the reactions of [MoOCl2 (THF)2]with XC6 H4 Y(X =NH2, Y = CN; X= CN, Y = OH; X = Y = NH2;X=NH2,Y=OCH3). All the new compounds were characterized by elemental analyses, and FTIR, UV-Vis, and 1 H and 13 C-NMR spectra. Geometrical parameters and molecular orbital calculations showed that compounds 2-5 are stabilized by a charge transfer between the Mo center and the phenyl ring.Article Citation - WoS: 16Citation - Scopus: 19Application of Experimental Design on Determination of Aluminum Content in Saline Samples by Adsorptive Cathodic Stripping Voltammetry(TUBITAK, 2013) Yılmaz, Sinan; Öztürk, Betül; Özdemir, Durmuş; Eroğlu, Ahmet Emin; Ertaş, Fatma NilAdsorptive cathodic stripping voltammetric determination of aluminum at ng mL-1 levels in salt samples based on the metal complexation with Calcon (1-(2-hydroxynaphthylazo)-2 naphthol-4-sulfonic acid) and the subsequent adsorptive deposition onto a hanging mercury drop electrode was studied. Central composite design was used as a design method. Several chemical and instrumental parameters (pH, ligand concentration, deposition time, deposition potential, and complexing time) were involved in the experimental design. Analytical parameters such as repeatability, linearity, and accuracy were also investigated and the detection limit was found as 0.32 ng mL-1.Article Citation - WoS: 18Citation - Scopus: 22Fucoxanthin Content of Cylindrotheca Closterium and Its Oxidative Stress Mediated Enhancement(Central Fisheries Research Inst, 2016) Erdoğan, Ayşegül; Demirel, Zeliha; Conk Dalay, Meltem; Eroğlu, Ahmet EminProduction of fucoxanthin by diatoms has become an alternative research area due to their low cost, convenience and diversity. The fucoxanthin content of Cylindrotheca closterium and its enhancement by altering the cultivation conditions via oxidative stress were investigated in this study. For this purpose, the extraction parameters were optimized and the highest fucoxanthin concentration (6.58 mg g-1) was achieved within 15.0 minutes at 40 °C. Then, this yield reached to 10.15 mg g-1 in the presence of NaOCl and Fe2+. It is worth noting that, this is the first time that the effect of oxidative stress on fucoxanthin production in diatom has been studied according to our knowledge. Therefore, the results of this study and the discussion about the mechanisms can be a reference for the enrichment of fucoxanthin from other diatoms.Article Citation - WoS: 2Citation - Scopus: 3Synthesis and Characterization of Nitrosyl[tris(3,5dimethylpyrazolyl) Borato]molybdenum Complexes Containing Aryloxo, Arylamido and Arylcyano Ligands(TUBITAK, 2005) Sözüer, Hikmet Işıl; Dülger İrdem, SeçkinerThe complexes [MoTp*(NO)X(ZC6H4CN-p)] [Tp* = 3,5-dimethylpyrazolyl; X = Cl, Z = O and NH; X = I, Z = CN) were prepared and characterized using 1H-NMR, IR, FAB mass spectroscopy and micro analysis.Article Citation - WoS: 16Citation - Scopus: 19Genetic Multivariate Calibration Methods for Near Infrared (nir) Spectroscopic Determination of Complex Mixtures(TUBITAK, 2004) Özdemir, Durmuş; Öztürk, BetülThe simultaneous determination of ternary mixtures of methylene chloride, ethyl acetate, and methanol using near infrared (NIR) spectroscopy and 4 different genetic algorithms based multivariate calibration methods was demonstrated. The 4 genetic multivariate calibration methods are genetic partial least squares (GPLS), genetic regression (GR), genetic classical least squares (GCLS) and genetic inverse least squares (GILS). The sample data set contains the NIR spectra of 63 ternary mixtures and covers the range from 900 to 2000 nm in 2 nm intervals. Of these 63 spectra, 42 were used as the calibration set, and 21 were reserved for the prediction purposes. Several calibration models were built with the 4 genetic algorithm based methods for each component that makes up the mixtures. Overall, the standard error of calibration (SEC) and the standard error of prediction (SEP) were in the range of 0.22 to 2.5 (% by volume (v/v)) for all the 4 methods. A comparison of genetic algorithm selected wavelengths for each component and for each method was also included.Article Citation - WoS: 2Citation - Scopus: 3The Amido and Bisalkoxo-Complexes of [tri(3,5-Dimethylpyrazolyl)borato]molydenum Nitrosyl(TÜBİTAK, 1998) Topaloğlu, IşılIn this study, the amido nitrosyl molybdenum complex, [Mo{HM(3,5-Me2C3HN2)3}(NO)Cl(NH 2)], was prepared. This compound reacts with alocohols, yielding the bisalkoxo complexes, [Mo{HM(3,5-Me2C3HN2)3}(NO)(OR) 2] (R = Me, Et, Prn, Bun). The new complexes were analyzed by IR and 1H-NMR spectroscopy.