PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article An Analytical Methodology for the Determination of Cadmium Bound To Whey-Proteins by Laser-Induced Breakdown Spectroscopy at Low Pressures(Elsevier, 2026) Erdogrul, Ilayda Yaman; Yalcin, Serife H.In this study, a dried-droplet LIBS methodology for determining cadmium in cow milk has been developed. The performance of the methodology was shown by standard and real protein samples. A standard protein, bovine serum albumin (BSA), and whey protein extracted from skim cow milk were incubated in standard Cd solutions, and the complex solution was filtered through cut-off filters by centrifugation. The unreacted cadmium in the filtrate and Cd-bound protein in the filtered fraction were loaded separately onto a Si-wafer substrate and analyzed via dried-droplet LIBS methodology. Measurements were performed at reduced pressures by taking advantage of the signal enhancement effect. The optimum pressure for most Cd emission lines was found to be 100 mbar. It has been shown that the dried-droplet LIBS methodology at reduced pressures can be used for the identification and determination of free and protein-bound Cd in the whey matrix. The concentration-based detection limit of Cd bound to whey proteins was determined to be 20.2 ng mL- 1, which corresponds to as low as 10 pg in absolute amount with a sample volume of 500 nL. The LOQ value is estimated as 67.3 ng mL- 1 and 33.3 pg, in terms of concentration unit and absolute amount, respectively. The use of small sample volumes is important in the analysis of limited amounts of samples, such as body fluids. Preconcentration studies with multiple loadings of the sample on the same spot resulted in improvements in concentration-based detection. 8 ng mL- 1 Cd in the whey matrix that could not be determined by a single droplet loading due to being below the detection limit; could be determined after 10 consecutive loadings. The methodology may also be applied to the determination of other toxic metals bound to proteins for food quality control.Article Citation - WoS: 1Citation - Scopus: 1High-Performance Polyether Sulfone (PES) Membranes Modified With Sunflower Seed Shell-Derived Activated Carbon (SSAC)@zif-11 Nanoparticles for Enhanced Antibiotic Removal and Antifouling Properties(Elsevier, 2025) Alafi, Narges Mortazazad; Barzegar, Behrad; Habibi, Rezvan; Aghdasinia, Hassan; Altinkaya, Sacide Alsoy; Barzegar, B.This study investigates the impact of incorporating a novel composite filler on the antibiotic removal efficiency and protein fouling resistance of polyether sulfone (PES) membranes. The filler was synthesized from activated carbon derived from sunflower seed shells (SSAC) and modified with zeolitic imidazolate framework-11 (ZIF-11). The adsorption capacities of the composite for two model antibiotics, tetracycline (TC) and rifampicin (RP), were evaluated. Mixed matrix membranes were fabricated using the phase inversion method with varying SSAC@ZIF11 contents (0.2-1 wt%). The membrane containing 0.8 wt% SSAC@ZIF-11 exhibited improved structural and surface characteristics, including increased porosity, larger pore size, smoother morphology, and enhanced hydrophilicity, as reflected by a reduction in contact angle from 60.72 degrees to 46.45 degrees. At this optimal loading, the pure water flux increased significantly from 10.52 to 39.1 L/m2h. Moreover, the modified membrane demonstrated outstanding removal efficiencies for TC (99.12 %) and RP (89.9 %), alongside excellent antifouling performance, as indicated by a flux recovery ratio increase from 42.85 % to 99.74 %. These results confirm the potential of SSAC@ZIF-11 as an effective nanofiller for developing high-performance PES membranes in advanced water purification applications.Article Citation - WoS: 2Citation - Scopus: 2Speciation of Inorganic and Organometallic Arsenic in Various Matrices With a Novel Spme Fiber Functionalized With Iron Nanoparticles Prior To Lc-Icp Determination(Elsevier, 2025) Boyaci, Ezel; Cagir, Ali; Shahwan, Talal; Eroglu, Ahmet E.A novel SPME-LC-ICP-MS methodology is described for the simultaneous microextraction/speciation/determination of the metabolically critical inorganic and organoarsenic species, namely, As(III), As(V), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) in natural waters such as drinking and geothermal waters, and biological fluids such as urine. The novelty of the study stems also from the use of home-made SPME fibers for the extraction process, and from the proposed methodology needing no derivatization step. SPME fibers were prepared with in-tube capillary template approach through the immobilization of iron nanoparticles into agarose matrix. The fibers demonstrated reproducible extraction (<10 % RSD), good mechanical strength and good solvent resistivity. The separation of the analytes was realized by HPLC with a strong anion exchange column via gradient elution using different concentrations of (NH4)(2)CO3 (pH 8.50), and the on-line detection of eluted analytes was achieved by ICP-MS. The validity of the proposed methodology was verified via the analysis of certified reference materials (SRM 1643e, Natural Water-Trace Elements, and SRM 2669, Arsenic Species in Frozen Human Urine) and through spike recovery tests. The values of percentage recovery for SRM 2669 were 90.7 % for As(III), 99.8 % for As(V), 93.6 % for DMA, and 85.9 % for MMA. A good correlation was also found between the certified (60.45 mu gL(-1)) and determined (59.00 mu gL(-1)) values for SRM 1643e. Moreover, the speciation capability of the method was demonstrated on various natural waters and biological fluids.Article Citation - WoS: 3Citation - Scopus: 3An Ex Vivo Model for Evaluation of Prebiotic Activity of Xylan and Xylooligosaccharides(Elsevier, 2025) Sabanci, Kevser; Gulec, Sukru; Buyukkileci, Ali OguzEx vivo techniques can provide more physiologically significant insights into prebiotic activity and overcome some limitations of in vitro tests. In this study, an ex vivo model, formed of a large intestine of mice, was tested to assess the effects of the hydrocolloidal natural polymer, xylan (XY), and its hydrolysis product, xylooligosaccharides (XOS). XY and XOS were loaded separately into the cecum, proximal colon, and distal colon. Their utilization and short-chain fatty acid (SCFA) formation by the colonized microflora and levels of dominant phyla and key genera such as Bifidobacterium, Bacteroides, and Lactobacillus were followed. XY and XOS were metabolized in all sections, and SCFAs were released. The results suggest that the slower utilization of XY compared to XOS in the cecum can enable this polysaccharide to move towards distal parts of the large intestine and extend the sites of prebiotic activity. Unlike widely used in vitro models, the ex vivo model allowed testing the utilization pattern and effects of the prebiotics in the natural environment of the microflora and examining the intestinal sections separately.Article Citation - WoS: 1Citation - Scopus: 1Assessment of Thermal and Solvent Stable Spme Fibers for Metabolomics Studies Performed in Living Systems(Elsevier, 2025) Kahremanoglu, Kuebra; Jaroch, Karol; Szeliska, Paulina; Filipiak, Wojciech; Charemski, Bartlomiej; Zuchowska, Karolina; Boyaci, EzelSolid phase microextraction (SPME), as a sampling/sample preparation technique, offers unique solutions for the most challenging applications, including metabolomics studies of living systems. However, for global metabolomics it is critical to use an SPME sampler facilitating the extraction of both volatiles and nonvolatiles, which at the same time is compatible with thermal and solvent-assisted desorption. As a promising universal coating, recently hydrophilic-lipophilic balanced (HLB) particles immobilized in PTFE have been introduced as a new SPME sampler to provide a wide-range of analyte coverage and compatibility with solvent and thermal desorption. Thus, making it suitable for both gas and liquid chromatography (GC/LC) based applications. However, its potential in metabolomics has not been investigated to date. In this study, HLB/PTFE SPME fibers were prepared, evaluated with selected polar and non-polar metabolites relevant to biological systems, and validated for cell-line studies. The validation proved that these fibers can extract a wide-range of molecules (LogP: 4.2 to 15.6) with acceptable accuracy (<= 19% RE%) and repeatability (intra-day <= 17% and inter-day 12% RSD%). The LOQ was determined to vary between 150.0 and 500.0 ng/mL. Upon validation, the fibers were used in a proof-of-concept study for extraction of endometabolome and exometabolome of melanoma B16F10 and lung cancer LL2 cell lines. The metabolome studies showed that HLB/ PTFE fibers provide lower coverage, but for some compounds higher extraction efficiency compared to HLB/PAN fibers used in LC-based metabolomics. Fibers also proved suitable for GC-MS analysis, allowing for the detection of 36 volatile organic compounds in the headspace of the cell lines and RPMI medium.Article Citation - WoS: 7Citation - Scopus: 7Quaternary Ammonium-Modified Cellulose: a Sustainable Strategy for Purifying Aqueous Solutions Contaminated With Sunset Yellow Dye(Elsevier, 2025) Toprakcurumez, Halil; Recepoglu, Yasar Kemal; Arar, OzgurThis study showcases the remarkable efficacy of quaternary ammonium-modified cellulose as a highly sustainable biosorbent for removing Sunset Yellow (SY) dye from water. Detailed analysis was conducted using infrared (FTIR) spectroscopy for structural changes and Scanning Electron Microscopy (SEM) for morphological changes. A minimal yet highly effective dose of 0.05 g was identified through dedicated optimization experiments, achieving near-complete removal (99 %) of SY. The biosorbent demonstrated exceptional performance across a broad pH range (2-10), accomplishing remarkable removal within just 5 min. Langmuir modeling uncovered a monolayer sorption mechanism with a high maximum capacity (107.08 mg g- 1), and thermodynamic analysis affirmed the spontaneity and favorability of the sorption process. Noteworthy is the biosorbent's impressive regeneration capabilities (up to 95 %) using 1.0 M NaOH or HCl solutions and its sustained performance over three sorption-regeneration cycles, highlighting its exceptional stability and reusability. The modified cellulose exhibited remarkable resistance to common interfering ions (chloride, nitrate, and sulfate) at 10 and 100 mg L- 1 concentrations. These combined features position quaternary ammonium-modified cellulose as a promising, sustainable, and efficient option for dye wastewater treatment.Article Citation - WoS: 8Citation - Scopus: 8Comparative Performance of Artificial Neural Networks and Support Vector Machines in Detecting Adulteration of Apple Juice Concentrate Using Spectroscopy and Time Domain Nmr☆(Elsevier, 2025) Cavdaroglu, Cagri; Altug, Nur; Serpen, Arda; Oztop, Mecit Halil; Ozen, BanuThe detection of adulteration in apple juice concentrate is critical for ensuring product authenticity and consumer safety. This study evaluates the effectiveness of artificial neural networks (ANN) and support vector machines (SVM) in analyzing spectroscopic data to detect adulteration in apple juice concentrate. Four techniques-UV-visible, fluorescence, near-infrared (NIR) spectroscopy, and time domain 1H nuclear magnetic resonance relaxometry (1H NMR)-were used to generate data from both authentic and adulterated apple juice samples. Adulterants included glucose syrup, fructose syrup, grape concentrate, and date concentrate. The spectroscopic data were pre-processed and analyzed using ANN and SVM models, with performance metrics such as sensitivity, specificity, and correct classification rates (CCR) evaluated for both calibration and validation sets. Results indicated that NIR spectroscopy combined with SVM provided the highest overall accuracy, with nearperfect specificity and high CCR values, making it the most robust method for adulteration detection. UV-visible and fluorescence spectroscopy also demonstrated strong performance but were slightly less consistent across different adulterants. 1H NMR relaxometry, while providing detailed molecular insights, showed variable sensitivity depending on the adulterant type. The findings showed the importance of selecting appropriate analytical techniques and machine learning models for food authentication. This study contributes to the development of non-destructive, rapid, and accurate methods for detecting food adulteration, which can help support industry efforts to enhance product integrity and maintain consumer trust.Article Citation - WoS: 4Citation - Scopus: 5Enhanced Performance and Anti-Fouling Properties of Polyether Sulfone (pes) Membranes Modified With Pistachio Shell-Derived Activated Carbon (psac)@zif-8&zif To Remove Dye Contaminants(Elsevier, 2024) Shakeri, Neda; Barzegar, Behrad; Habibi, Rezvan; Aghdasinia, Hassan; Altinkaya, Sacide AlsoyThis study aims to improve the properties of polyether sulfone (PES) membranes by using an innovative composite filler. Pistachio shell-derived activated carbon (PSAC) was initially synthesized via chemical activation, followed by surface modification with ZIF-8 and ZIF-67. Subsequently, modified membranes with varying weight percentages of this composite were fabricated using the phase inversion method. The PSAC@ZIF-8&ZIF-67/PES membranes were characterized through FESEM, AFM, pore size, zeta potential, porosity, and water contact angle analyses. The incorporation of the composite in the membranes was confirmed through ATR-FTIR, XRD, and EDS mapping analyses. The finding indicated that adding 0.6 wt% of nanoparticles improved membrane hydrophilicity, increased surface charge, and enhanced porosity. Additionally, the mixed membranes exhibited reduced sedimentation and higher dye removal than unmodified membranes. The optimum amount of composite is determined as 0.6 wt%. At this condition, pure water flux (PWF) increased dramatically from 22.56 L/m2h to 96.26 L/m2h. The mixed matrix membrane demonstrated superior efficiency in removing malachite green (MG) (97 %) and crystal violet (CV) dyes (93 %) and achieved the highest recovery ratio of 61.9 %, indicating a more remarkable membrane ability to combat fouling. The developed membrane demonstrated enhanced hydrophilicity, dye removal efficiency, and antifouling properties, making it promising for environmental applications.Article Citation - WoS: 4Citation - Scopus: 6Effect of Boramidic Acid Modified Carbon Nanotubes on Neurological, Morphological and Physiological Responses of Zebrafish (danio Rerio) Embryos and Larvae(Elsevier, 2024) Yigit, Aybek; Kokturk, Mine Ko; Yildirim, Serkan; Nazli, Dilek; Kiliccioglu, Metin; Sahin, Ayse; Alak, GoncaThis study aimed to determine the potential toxicological effects of carbon nanotubes (CNTs), their modifications with ethylenediamine (ED) and boric acid (BA) on aquatic organisms. Specifically, the research focused on the morphological, physiological, and histopathological-immuno-histochemical responses in zebrafish (Danio rerio) embryos and larvae, via applying different concentrations of CNTs, CNT-ED, and CNT-ED-BA (Control, 5, 10, and 20 mg/L). The results indicated that 20 mg/L CNT nanoparticles were toxic to zebrafish larvae, with mortality rates increasing with CNT and CNT-ED concentrations, reaching 36.7 % at the highest CNT concentration. The highest dose caused considerable degeneration, necrosis, DNA damage, and apoptosis, as evidenced by histopathological and immunohistochemical tests. In contrast, despite their high concentration, CNT-ED-BA nanoparticles exhibited low toxicity. Behavioral studies revealed that CNT and CNT-ED nanoparticles had a more significant impact on sensory-motor functions compared to CNT-ED-BA nanoparticles. These findings suggest that modifying the nanosurface with boric acid, resulting in boramidic acid, can reduce the toxicity induced by CNT and CNT EDArticle Citation - WoS: 9Citation - Scopus: 8Depression in Older Adults and Its Associations With Sleep and Synaptic Density(Elsevier, 2024) Didikoglu, Altug; Guler, Esin Simge; Turk, Halil Kaan; Can, Kubilay; Erim, Aleyna Nur; Payton, Antony; Maharani, AsriBackground: Depression among older adults is a global concern, contributing to disability and overall illness burden. Understanding its trajectory, associated risk factors, and implications for mortality is essential for effective intervention. Moreover, the relationship between depression, sleep disturbances, and synaptic density in the ageing brain remains complex and poorly understood. Methods: Using data from the University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age cohort, comprising 6375 participants, we conducted comprehensive assessments of depression trajectories using generalized linear mixed models and mortality risks using Cox mixed-effects models. Generalized structural equation modelling was performed to explore longitudinal associations between sleep duration and depression. Lastly, associations between post-mortem synaptic density and depression were investigated. Results: Our findings revealed that depression rates declined until age 80 before increasing again. Depression was associated with a 10 % increased risk of mortality in older adults. Reduced sleep was correlated with depression, and depression measured early in the study predicted future reduced sleep. Post-mortem analysis showed a global reduction in synaptic density associated with depression, particularly pronounced in the frontal lobe. Limitations: Limitations include recall bias, limiting generalizability due to dominantly including White British participants and difficulty in establishing causation between synaptic density and depression. Conclusion: Our study underscores the significance of addressing depression in older adults, not only for mental health but also for mortality risk and neurobiological health. Early detection and intervention strategies are crucial for improving outcomes in elderly populations, potentially mitigating adverse effects on sleep, synaptic density, cognitive health, and longevity.