PubMed İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/397
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Article Development and Characterization of Starch-Fatty Acid Complexes Produced with Buckwheat Starch and Capric/Stearic Acid Using Different Reaction Conditions(Elsevier, 2025-12) Oskaybas-Emlek, Betul; Ozbey, Ayse; Aydemir, Levent Yurdaer; Kahraman, KevserThe aim of present study was to investigate the impact of reaction parameters on the complex formation between buckwheat starch and capric acid (B-Capric) or stearic acid (B-Stearic). The most effective parameters on complex formation indicator (Complex index (CI) value) were found as reaction temperature (60-90 degrees C) and pH (5-8). Additionally, the effect of these parameters on physicochemical, pasting, and in-vitro digestibility properties of complex samples were evaluated. XRD and FTIR was also used in characterize the complex samples. In general, increasing pH increased the CI values of B-Stearic samples while decreasing those of B-Capric samples. Syneresis of buckwheat starch increased after complexation while paste clarity and swelling power diminished. The pasting properties of native starch significantly changed after complex formation. The FTIR results showed that starch structure changed with complex formation. XRD revealed that buckwheat starch, having an A-type pattern, converted to V-type pattern after complexation. Complex formation of buckwheat starch with capric and stearic acid significantly increased the RS content of buckwheat starch (19.01 %) by up to 36.25 % and 30.60 %, respectively. These results highlight the possibility of using buckwheat starch-capric acid/stearic acid complexes in food formulation to enhance the RS content.Article Citation - WoS: 16Citation - Scopus: 22Ultrasonic-Assisted Production of Precipitated Calcium Carbonate Particles From Desulfurization Gypsum(Elsevier, 2021-04) Altiner, Mahmut; Top, Soner; Kaymakoglu, BurcinThis study aimed to investigate the effect of ultrasonic application on the production of precipitated calcium carbonate (PCC) particles from desulfurization gypsum via direct mineral carbonation method using conventional and venturi tube reactors in the presence of different alkali sources (NaOH, KOH and NH4OH). The venturi tube was designed to determine the effect of ultrasonication on PCC production. Ultrasonic application was performed three times (before, during, and after PCC production) to evaluate its exact effect on the properties of the PCC particles. Scanning electron microscope (SEM), X-ray diffraction (XRD), Atomic force microscope (AFM), specific surface area (SSA), Fourier transform infrared spectrometry (FTIR), and particle size analyses were performed. Results revealed the strong influence of the reactor types on the nucleation rate of PCC particles. The presence of Na+ or K+ ions in the production resulted in producing PCC particles containing only calcite crystals, while a mixture of vaterite and calcite crystals was observed if NH4+ ions were present. The use of ultrasonic power during PCC production resulted in producing cubic calcite rather than vaterite crystals in the presence of all ions. It was determined that ultrasonic power should be conducted in the venturi tube before PCC production to obtain PCC particles with superior properties (uniform particle size, nanosized crystals, and high SSA value). The resulting PCC particles in this study can be suitably used in paint, paper, and plastic industries according to the ASTM standards.Article Citation - WoS: 358Citation - Scopus: 392The Use of Ecological Footprint in Estimating the Environmental Kuznets Curve Hypothesis for BRICST by Considering Cross-Section Dependence and Heterogeneity(Elsevier, 2020-06) Dogan, Eyup; Ulucak, Recep; Kocak, Emrah; Isik, CemA vast body of literature estimates the impact of economic growth on environmental degradation in the framework of EKC model. Typical empirical studies proxy environmental degradation with CO2 emissions; however, this indicator does not consider the complex nature of environmental degradation. To fulfill this omission, ecological footprint that tracks the use of multiple categories of productive surface areas is used as proxy for the environment. Moreover, studies that do not consider issues of heterogeneity and cross-sectional dependence may not produce reliable outcomes. Hence, the present study re-investigates the validity of the EKC hypothesis for BRICST (Brazil, Russia, India, China, South Africa, Turkey) by using ecological footprint and considering the mentioned issues in the estimation process. Based on the annual data covering the period of 1980-2014, excluding Russia due to data unavailability, empirical results show that the EKC hypothesis is not valid, and energy intensity and energy structure are important determinants of environmental degradation. In line with the empirical outputs, possible policy suggestions are discussed in the present study. (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 135Citation - Scopus: 138The Impacts of Different Proxies for Financialization on Carbon Emissions in Top-Ten Emitter Countries(Elsevier, 2020-10) Amin, Azka; Dogan, Eyup; Khan, ZeeshanThe nexus of financialization and carbon emissions has been widely discussed in the literature. A vast body of literature that estimates the impact of financialization on carbon emissions proxies financialization with either domestic credit or market capitalization. However, these representatives do not fully respond to the complicated nature of financial development. To till the gaps in the existing literature, nine different proxies for financial development are used in the links with carbon emissions in the framework of EKC theory for the years 1980-2014. This study exposes reliable and robust empirical results due to the use of a number of proxies for financialization and second-generation econometric approaches in the empirical analysis. The quantile regression approach deals with unobserved heterogeneity for each cross-section and estimates different slope parameters at varying quantiles. Because non-normality and heterogeneity are detected in datasek quantile regression provides more robust and reliable estimates than conventional econometric techniques. Results from quantile regression estimator support mixed effects of financial development on carbon emissions over quantiles: in addition, the impact of financial development on carbon emissions is varying not only for each quantile but also for different proxies of financial development. The EKC hypothesis is validated for the top-ten emitter economies. Interpretations and policy suggestions are further discussed in the present study. (C) 2020 Elsevier B.V. All rights reserved.Article Citation - WoS: 25Citation - Scopus: 33Production of Buckwheat Starch-Myristic Acid Complexes and Effect of Reaction Conditions on the Physicochemical Properties, X-Ray Pattern and FT-IR Spectra(Elsevier, 2022-05) Oskaybas-Emlek, Betul; Ozbey, Ayse; Aydemir, Levent Yurdaer; Kahraman, KevserIn this study, the effect of reaction parameters on complex index (CI%) value of complexes formed between buckwheat starch (BS) and myristic acid (MA) was investigated. The temperature (60-90 ?C) and MA to BS ratio (0.1-0.8 mmoL/g) were determined as the most effective parameters and their effect on CI% was evaluated using response surface methodology. The MA to BS ratio, temperature, and interaction between them had an influence on CI%. The CI% of BS-MA complexes increased with increasing MA ratio until a certain level of MA. Principal component analysis (PCA) was used for correlation analysis between parameters. Swelling power and paste clarity of BS decreased with complex formation while syneresis increased. Peak and final viscosity values of the BS-MA complexes were significantly lower than those of BS. FT-IR revealed the complex formation led to change in starch structure. The XRD confirmed the BS-MA complex formation but the BS-MA produced using 0.1 mmoL/ g at 60 ?C was not detected by XRD due to having low crystallinity, and expectedly, the lowest relative crystallinity value was achieved with this sample among complex samples. All results showed that the buckwheat be an alternative starch source for starch formation.Article Citation - WoS: 13Citation - Scopus: 15Prevention of Cisplatin-Induced Nephrotoxicity by Kidney-Targeted siRNA Delivery(Elsevier, 2022-11) Aydin, Erkin; Cebeci, Aysun; Lekesizcan, AycaCisplatin is a potent and widely used chemotherapy agent, however, nephrotoxicity limits its use. Many patients need to pause or withdraw from chemotherapy to prevent acute kidney injury. To prevent cisplatin damage, we designed chitosan/siRNA nanoparticleswhich are nontoxic and are readily taken up by HEK293 cells. The nanoparticles contained siRNA against cationic membrane transport (OCT1&2) and apoptosis related proteins (p53, PKC8, and gamma GT). In mice treated with cisplatin, serum creatinine levels increased from 15 to 88 mg/dL and blood urea nitrogen levels increased from 0.25 to 1.7 mg/dL, however, siRNA nanoparticles significantly limited these levels to 30 mg/dL and 0.55 mg/dL, respectively. Western and IHC analyses showed lower p53, PKC8, and gamma GT expressions in siRNA treated mice. Histomorphological evaluation revealed high-level protection of kidney proximal tubules from cisplatin damage. Protein expressions and extent of kidney protection were directly correlated with number of siRNA applications. Our results suggest that this novel approach for kidney -targeted delivery of select siRNAs may represent a promising therapy for preventing cisplatin-induced nephro-toxicity. Furthermore, this or other similarly sized nanocarriers could potentially be utilized to passively target kidneys for diagnostic, protective, or treatment purposes.Article Citation - WoS: 40Citation - Scopus: 63Optimization of Resistant Starch Formation From High Amylose Corn Starch by Microwave Irradiation Treatments and Characterization of Starch Preparations(Elsevier, 2017-02) Mutlu, Selime; Kahraman, Keyser; Ozturk, SerpilThe effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2-4min) and power (20-400%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2 min. The F, p (<0.05) and R-2 values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones. (C) 2016 Elsevier B.V. All rights reserved.Article Citation - WoS: 8Citation - Scopus: 8Comparative Genomics of Loigolactobacillus Coryniformis With an Emphasis on L. Coryniformis Strain FOL-19 Isolated From Cheese(Elsevier, 2023) Gumustop, Ismail; Ortakci, FatihLoigolactobacillus coryniformis is a member of lactic acid bacteria isolated from various ecological niches. We isolated a novel L. coryniformis strain FOL-19 from artisanal Tulum cheese and performed the whole-genome sequencing for FOL-19. Then, genomic characterization of FOL-19 against ten available whole genome sequences of the same species isolated from kimchi, silage, fermented meat, air of cowshed, dairy, and pheasant chyme was performed to uncover the genetic diversity and biotechnological potential of overall species. The average genome size of 2.93 +/- 0.1 Mb, GC content of 42.96% +/- 0.002, number of CDS of 2905 +/- 165, number of tRNA of 56 +/- 10, and number of CRISPR elements of 6.55 +/- 1.83 was found. Both Type I and II Cas clusters were observed in L. coryniformis. No bacteriocin biosynthesis gene clusters were found. All strains harbored at least one plasmid except KCTC 3167. All strains were predicted to carry multiple IS elements. The most common origin of the IS elements was belong to Lactiplantibacillus plantarum. Comparative genomic analysis of L. coryniformis revealed hypervariability at the strain level and the presence of CRISPR/Cas suggests that L. coryniformis holds a promising potential for being a reservoir for new CRISPR-based tools. All L. coryniformis strains except PH-1 were predicted to harbor pdu and cbi-cob-hem gene clusters encoding industrially relevant traits of reuterin and cobalamin biosynthesis, respectively. These findings put a step forward for the genomic characterization of L. coryniformis strains for biotechnological applications via genome-guided strain selection to identify industrially relevant traits.Article Citation - WoS: 2Citation - Scopus: 2Cinnamomum Zeylanicum Extract Incorporated Electrospun Poly(Lactic Acid)/ Gelatin Membrane as a New Wound Dressing(Elsevier, 2025-08) Tarhan, Seray Zora; Pepe, Nihan Aktas; Sen, Alaattin; Isoglu, Ismail AlperIn this study, we fabricated poly(lactic acid)/gelatin electrospun membranes containing various concentrations of Cinnamomum zeylanicum extract and evaluated them as a novel wound dressing. The electrospun membranes were chemically, morphologically, and mechanically characterized, and the results were discussed in comparison with the literature. Electrospun membranes' biodegradability, swelling, and release properties were evaluated, with the CE7.5 membrane having values of 29.60 f 7.20 and 542.1 f 48.3 % and 66.9 %, respectively. Antibacterial activity was observed in CE7.5 and CE10 membranes against E. coli and S. aureus strains. At the highest concentration (CE10), 111.7 f 5.6 % and 96 f 12.375 % cell viability were detected in fibroblasts and differentiated LPS-induced THP-1 cells. Cell viability was further evaluated by Annexin-V/PI staining, revealing that 97.95 f 1.63 % of the cells remained viable in the CE7.5-treated membranes, while only 1.85 f 1.49 % of necrotic cells were detected in the treated cell population. Fibroblasts treated with the CE7.5 membrane showed a 42 % improvement in wound closure compared to non-treated cells. The anti-inflammatory properties of the electrospun membranes were also investigated. Treatment with the conditioned CE7.5 membrane downregulated Tba1 and tau proteins by 45.1 and 51.055 %, respectively. This study concluded that the newly developed Cinnamomum zeylanicum extract incorporated poly(lactic acid)/gelatin electrospun membranes could be a promising wound dressing material.Article Citation - WoS: 8Citation - Scopus: 14A Fractional-Order Mathematical Model Based on Vaccinated and Infected Compartments of Sars-Cov With a Real Case Study During the Last Stages of the Epidemiological Event(Elsevier, 2023-06) Bilgil, Halis; Yousef, Ali; Erciyes, Ayhan; Erdinc, Ummugulsum; Ozturk, ZaferIn 2020 the world faced with a pandemic spread that affected almost everything of humans' social and health life. Regulations to decrease the epidemiological spread and studies to produce the vaccine of SARS-CoV-2 were on one side a hope to return back to the regular life, but on the other side there were also notable criticism about the vaccines itself. In this study, we established a fractional order differential equations system incorporating the vaccinated and re-infected compartments to a SIR frame to consider the expanded and detailed form as an SVIIvR model. We considered in the model some essential parameters, such as the protection rate of the vaccines, the vaccination rate, and the vaccine's lost efficacy after a certain period. We obtained the local stability of the disease-free and co-existing equilibrium points under specific conditions using the Routh-Hurwitz Criterion and the global stability in using a suitable Lyapunov function. For the numerical solutions we applied the Euler's method. The data for the simulations were taken from the World Health Organization (WHO) to illustrate numerically some scenarios that happened.(c) 2022 Elsevier B.V. All rights reserved.