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Öğe Anion effect on magnetic and structural properties of green synthesized NiO nanoparticles via Ni.salt precursors in Salvia officinalis extract(Chinese Chemical Soc, 2024) Zenkin, Kubra; Dalmaz, Aslihan; Ozdincer, Mesut; Durmus, SefaUsing a green synthesis method, Salvia officinalis extract was used as a reducing and capping agent to synthesize nickel oxide nanoparticles (NiO NPs). In addition, NiO NPs were synthesized using various precursors, and their morphologies were analyzed using scanning electron microscopy. The structures of NiO NPs were characterized using Fourier-transform infrared spectroscopy, and powder X-ray diffraction (PXRD). Their magnetic properties were measured using a vibrating sample magnetometer. PXRD studies showed that all synthesized NiO NPs exhibited a face-centered cubic phase with high crystallinity, and NiO formations with a high-purity phase were confirmed. As a result of magnetization studies, NiO NPs synthesized from three nickel salt precursors (acetate, chloride, and sulfate) exhibit superparamagnetic, soft ferromagnetic, and paramagnetic behaviors, respectively.Öğe Biological evaluation of benzothiazoles obtained by microwave-green synthesis(Acad Brasileira De Ciencias, 2024) Ozdincer, Mesut; Dalmaz, Aslihan; Durmus, Sefa; Dülger, Görkem; Kiliccioglu, IlkerBenzothiazole compounds are known as an important bicyclic ring system with multiple applications. These compounds have a wide range of biological activities, including anticancer, antimicrobial, anti-inflammatory and antiviral activities. In this study, benzothiazole compounds were synthesized and their various biological activities were examined. The synthesized benzothiazoles were evaluated for their antimicrobial properties against various bacterial and fungal strains. The compound 6e is most active ligand in the series against bacteria and fungi as compared to standard antibiotics. Especially, this compound significant effect against Staphylococcus aureus (32.00 +/- 1.73 mm). These compounds exhibited potent anticancer activity against gastrointestinal cancer cells, demonstrating their potential as therapeutic agents. The lowest antiproliferative response after administration of the compounds was observed in HCT116 cells, while the most effective antiproliferative response was observed in AGS cells (> 10 mu g/mL). In all cell lines, 40 and 100 mu g/mL application values of the selected compounds showed significant increases in the expression of caspase-3, 8 and 9. We also utilized a computational docking approach to investigate the interaction of these benzothiazoles with VEGFR-2 kinase. Our docking studies showed that compounds 6a and 6d may be promising therapeutic agents against gastrointestinal system cancers due to their ability to bind to VEGFR-2 kinase.Öğe Green and simple microextraction method based on deep eutectic solvent-assisted smartphone digital imaging colorimetry (SDIC) for Rhodamine B analysis in food products(Springer Heidelberg, 2025) Tezcan, Buse; Dalmaz, Aslihan; Ozak, Sezen SivrikayaThis study employed a deep eutectic solvent-based liquid-liquid microextraction method and smartphone digital image colorimetry to detect and quantify Rhodamine B in foods. The deep eutectic solvent, a green solvent, was prepared by mixing tetrabutylammonium bromide and octanol in a 1:2 ratio. It was observed that Rhodamine B dyestuff readily transitioned to the DES phase, eliminating the need for additional reagents. The impact of various parameters, including DES type, molar ratio, volume, solution pH, ultrasonic time, centrifugation time, and sample volume, on extraction efficiency was examined, and the most effective conditions were determined. Additionally, the diameter of the prepared colorimetric box and the distance between the detector and the sample were investigated, leading to the identification of optimal conditions. The developed method's limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.0054 mu g/mL and 0.018 mu g/mL, respectively, for the measurements taken using seven parallel blank solutions at 554 nm. The relative standard deviations intraday and interday were 1.29% and 2.03%, respectively. The calibration graph demonstrated good linearity, with a coefficient of determination of 0.9996. The developed method's intraday and interday relative standard deviation values were 2.03% and 1.29%, respectively. Rhodamine B was detected in food samples using the developed method, obtaining extraction recoveries ranging from 95.16 to 103.88%.Öğe Green synthesis of ZnO nanoparticles using Laurus nobilis L. extract and investigation of corrosion inhibition properties of DES-based nanofluids(Springer, 2024) Dalmaz, Aslihan; Kasimfirtina, Eren; Ozak, Sezen SivrikayaIn this study, new nanofluids based on four different deep eutectic solvents consisting of acetic acid and ethylene glycol as hydrogen bond acceptors, choline chloride, and water as hydrogen bond donor were prepared and these deep eutectic solvents, ZnO used to influence the corrosion of nanoparticles. The study's originality is that for the first time in this study, ZnO nanoparticles obtained with the help of the green material deep eutectic solvent and the extract of Laurus nobilis L. leaves were used effectively in the corrosion study. As a result of the corrosion studies, the best corrosion prevention efficiency was determined in the nanofluid prepared by adding 0.015% by weight ZnO nanoparticles. According to the XRD analysis results, the synthesized ZnO nanoparticles are formed in a hexagonal structure. When the SEM images of ZnO nanoparticles were examined, it was seen that the obtained structure was homogeneous, and the dimensions of the nanoparticles varied between 12 and 33 nm. The thermal stability of ZnO nanoparticles was proven from the TGA curve, where only a 2% weight loss was observed. ZnO nanoparticles did not undergo any degradation up to 1000(degrees)C.Öğe Hydrophilic deep eutectic solvent based microextraction procedure for the determination of four paraben preservatives in vitamin D for babies: A green approach(Elsevier, 2023) Akmes, Ali; Dalmaz, Aslihan; Ozak, Sezen SivrikayaIn this study, an easily available, sensitive, and fast hydrophilic deep eutectic solvent-liquid phase microextraction method developed using deep eutectic solvent (DES) as a green solvent for the determination and microextraction of paraben (methyl, ethyl, propyl, and butyl) preservatives in vitamin D for babies. The highest yield for extraction recovery was obtained using DES consisting of a 1:4 M ratio of choline chloride and acetic acid. Moreover, various optimization parameters such as DES volume, DES type, sample volume, and centrifugation time were investigated in order to develop a real sample specific microextraction method. Relative standard deviation values were 0.92%-2.87%, the detection limit was 0.194-0.254 & mu;g/mL, and extraction recovery values were between 87.40% and 102.98%. The method developed in this study was successfully applied to 5 different babies in vitamin D for babies obtained from pharmacies for the determination of methyl, ethyl, propyl, and butylparaben. As far as we know, it is the first study conducted both in terms of the determination of paraben preservatives in vitamin D for babies and in terms of the fact that DES used in this study is used for the first time in vitamin D for babies.Öğe Methylene blue dye efficient removal using activated carbon developed from waste cigarette butts: Adsorption, thermodynamic and kinetics(Elsevier Sci Ltd, 2024) Dalmaz, Aslihan; Sivrikaya Ozak, SezenThis study aimed to obtain activated carbon using waste cigarette butts, which is one of the most harmful and toxic environmental materials. In addition, cigarette butts were converted into activated carbon in the thermal carbonization stage using ZnCl2 (1:2 ratios by mass) as a chemical activator. Brunauer-Emmett-Teller test, Fourier transform infrared spectrometry, Scanning electron microscope, and Elemental analysis were used to determine the activated carbon's surface morphology, elemental composition, functional group, and surface properties. As a result of the Brunauer-Emmett-Teller test, it was observed that the activated carbon obtained had a high surface area of 667.9 m2/g. In the study, it was determined that the Langmuir model can best describe the adsorption isotherm model. In addition, the maximum adsorption capacity of activated carbon for methylene blue dye was 285.7 mg g -1 at 25 degrees C. The results obtained in the study support that the pore structure of cigarette butts will be one of the strong alternatives in the production of activated carbon for the removal of methylene blue dye.Öğe Rapid and eco-friendly microextraction procedure based on green hydrophobic deep eutectic solvent for simultaneous determination of five sex hormones from cosmetic samples(Elsevier, 2024) Dalmaz, Aslihan; Ozak, Sezen SivrikayaHormones, which are among the endocrine disruptors, are used in many fields and their use in cosmetic products has recently attracted considerable attention. Despite the negative health consequences, there is no detailed guidance that limits the use of these endocrine disruptors. This study aimed to develop a green hydrophobic deep eutectic solvent (HDES)-based microextraction method for the detection and quantification of sex hormones (progesterone, (3-estradiol, estrone, ethinylestradiol, and testosterone) in different cosmetic products. The best value for extraction recovery was obtained by using DL-menthol and dodecanoic acid as green HDES in a 4:1 mole ratio. Optimization parameters such as HDES volume, pH, sample volume, centrifugation time, mixing type, and mixing time were investigated for cosmetic samples to be used as real samples. Furthermore, the extraction recovery values ranged from 85.7 % to 101.3 % and the detection limit was between 2.33-3.30 ng mL- 1. Additionally, three different greenness methods, namely ComplexGAPI, AGREEprep, and BAGI, were used to evaluate how green the proposed method is in this study. The microextraction procedure developed in this study was successfully applied to five different cosmetic samples that will be used as real samples to detect and determine sex hormones.Öğe Simultaneous microextraction of Brilliant Blue FCF, Malachite Green, and Rhodamine B in children's play materials: Assessment of greenness approach(Pergamon-Elsevier Science Ltd, 2025) Dalmaz, Aslihan; Ozak, Sezen SivrikayaThe types, quantities, and permissible limits of dyestuffs used in the toy industry are susceptible since the relevant audience is children. For this reason, the dyestuffs used in children's play materials are one of the crucial issues to be emphasized. Rhodamine B, Brilliant Blue FCF, and Malachite Green are some of the most commonly used dyestuffs, and they are also included in our study. In addition to making play materials fun for children, it is vital to determine the amount of the dye in the play material to know the damage it will cause. For this purpose, an ultrasonically assisted, rapid, and highly sensitive green deep eutectic solvent-based microextraction method was developed to detect three synthetic dyes in different children's play materials. Extraction recoveries were between 92.8 and 103.2% under optimum conditions. The method was promising when the results obtained were compared with other studies. When additional recovery studies were carried out on different children's play materials, Rhodamine B in pink-coloured playdough and finger paint, Brilliant Blue FCF in blue-coloured playdough, finger paint, and watercolour paint, and Malachite green dyestuffs in finger paint and crayon were detected. In addition, this study is noteworthy as it is the first study in which simultaneous determination of three dyestuffs by high-performance liquid chromatography method was carried out.Öğe Spectrophotometric determination for green hydrophobic deep eutectic solvent-based microextraction of Brilliant Blue FCF (E133) from beverages(Elsevier, 2024) Olgun, Mahmut; Ozak, Sezen Sivrikaya; Dalmaz, AslihanIn this study, a simple, sensitive, and rapid method called green hydrophobic deep eutectic solvent-based liquid- liquid microextraction was developed to extract Brilliant Blue FCF dye from beverages. This method utilizes hydrophobic DES obtained by forming tetrabutylammonium bromide and 1-octanol in a 1:5 ratio as green extraction solvent. The transition of Brilliant Blue FCF to the DES phase occurred on its own, without the need for any reagents such as added salt or tetrahydrofuran. Several crucial factors were tried to get the best extraction efficiency, including species, DES volume and molar ratio, solution pH, ultrasonication, and centrifugation time. Under optimum conditions, extraction recoveries were achieved in the range of 95.1-101.3 % with the method developed for Brilliant Blue FCF. The detection and determination limits were observed to be 4.1 mu g L-1 and 12.1 mu g L-1, respectively. In addition, the relative standard deviation values for the method's accuracy were found to be 2.23 % and 3.48 % within and between days, respectively. It has been established that the developed method is highly environmentally friendly thanks to the application of the Analytical GREENness (AGREE) and Green Analytical Procedure Index (GAPI) tools. This study shows that DES applications can be carried out without the use of emulsifiers and dispersants by prioritizing the use of hydrophobic DES compounds as environmentally friendly and green extraction solvents in food samples.Öğe Supramolecular solvent based microextraction for green and selective spectrophotometric determination of Rhodamine B in makeup products(Taylor & Francis Ltd, 2025) Yildiz, Ilayda Nur; Dalmaz, Aslihan; Ozak, Sezen SivrikayaMany dyes are used for various purposes in different industries and are often complex organic compounds. Many analytical techniques are inadequate to determine the concentrations of these dyes. Additionally, prolonged exposure to dyes can lead to serious health issues. For these reasons, dye quantification has become more important, and the pre-concentration method has been developed and used to determine the dye concentration. In this study, a supramolecular solvent-based liquid-phase microextraction method was developed and utilized for the enrichment and UV-Vis spectroscopic determination of Rhodamine B dye added to various cosmetic samples. Moreover, the effects of the parameters determining the supramolecular solvent, pH, centrifugation time, sample volume, and ultrasonic bath time were optimized. The advantages of the developed method compared to other methods are that the extraction time is very short, solvents and chemicals do not require high cost, and do not require the use of large volumes. Thus, this method has been shown to be a useful, reliable, fast, and valid method for the determination of Rhodamine and similar dyes used in cosmetics. Under optimum conditions, the detection limit was 1.31 mu g L-1, the linear range was 5-1000 mu g L-1, the correlation coefficient was 0.9994, the intra-day relative standard deviation was 2.12 mu g L-1, and the inter-day relative standard deviation was 3.30 mu g L-1. The microextraction method was successfully applied to determine Rhodamine B dyestuff in different cosmetic samples such as lipstick, nail polish, eyebrow fixative, blush, and peeling.Öğe Treatment of silicate Ion with Bacillus subtilis bacteria in demineralization-water/steam cycles in power plants(2025) Bozkurt, Deniz; Dalmaz, Aslihan; Durmus, SefaInorganic silica and various mineral deposits are particularly important in the process waters of power plants. The presence of these inorganic species, especially silica, poses many challenges for process water applications in power plants. If silica in process waters is not controlled, it forms hard, difficult, and dangerous deposits for process water. Silica formation and accumulation cannot be prevented by many conventional methods and scale inhibitors. In this study, Bacillus subtilis bacteria was used to minimize silica formation in the process water of power plants. For this purpose, many different parameters were optimized in the system steps. The results obtained are promising for the use of silica removal in process water applications. In addition, the use of Bacillus subtilis bacteria for the treatment of process water will provide significant economic benefits. Therefore, this study will make an important contribution to the literature and will be very advantageous in terms of cost for various industrial organizations that face silica problems in process waters.
