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    Effects of Spinel Oxide Combustion Catalysts on the Combustion Behavior and Secondary Atomization Mechanism of Gasoline Droplets
    (Taylor & Francis Inc, 2025) Kucukosman, Ridvan; Yontar, Ahmet Alper; Unlu, Cumhur Gokhan; Ocakoglu, Kasim
    The catalytic activity of Mg-based spinel oxide nanoparticles (NPs) on the combustion behavior of gasoline and their effects on the atomization behavior were determined by droplet scale combustion experiments. MgFe2O4, MgCo2O4 and MgMnO3 spinel oxide NPs were produced by the sol-gel technique and doped into gasoline. The particles with the highest surface oxygen were MgCo2O4 and MgFe2O4 NPs, while the NPs with the largest surface area were MgCo2O4 NPs (517.8433 m(2)/g). The size of the flame envelope tends to shrink as the oxygen concentration of the particles rises, but an increase in their surface area tends to shorten ignition delay periods. MgFe2O4 NPs increased the flame temperature by 163 & DEG;C compared to the pure gasoline. While MgFe2O4 and MgMnO3 NPs increased the extinction time of gasoline, MgCo2O4 NPs decreased the severe time by about 75% with the violent micro-explosions they created. In this study, we focused on the production of spinel oxide agents customized for combustion with improved catalytic activity, high flammability, and different component designs, and the results showed that these particles can reduce the soot formation of conventional hydrocarbons.
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    Photothermal and photodynamic responses of core-shell Mo2C@C@Fucoidan nanospheres
    (Elsevier Science Sa, 2025) Tuncel, Ayca; Sert, Buse; Ozel, Derya; Kaya, Gul; Harputlu, Ersan; Unlu, Cumhur Gokhan; Ocakoglu, Kasim
    Mo2C structure, a transition metal carbide, is known for its exceptional properties including high chemical and thermal stability and surface activity. Recently, carbon-modified Mo2C structures have found widespread applications due to their effectiveness. Here, we synthesized pomegranate-like Mo2C@C nanospheres and coated them with poly(allylamine hydrochloride) (PAH) and fucoidan structures. Characterization techniques including FE-SEM, HR-TEM, XRD, XPS, and zeta potential analysis were employed. We investigated the effect of Mo2C@C@Fuc nanospheres by quantitatively evaluating their photothermal conversion efficiency. Under irradiation at wavelengths of 808 nm and 1064 nm with a power intensity of 2 W/cm2, these nanospheres could convert up to 15 % of the incident laser energy into heat, outperforming conventional materials. Stability tests in various physiological pH environments confirmed their durability under NIR irradiation, ensuring operational integrity in biological environments. In addition, they showed significant efficiency in the production of singlet oxygen, making them promising agents for PDT. Biodegradation studies indicated safe degradation after ther- apeutic application, highlighting their environmental and physiological compatibility. Integrating Mo2C@C@- Fuc nanospheres into anticancer strategies combines the advantages of PTT and PDT, promising improved therapeutic outcomes with high biocompatibility.
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    Synthesis and characterization of perovskite type of La1-xBaxMnO3 nanoparticles with investigation of biological activity
    (Elsevier, 2022) Gonca, Serpil; ozdemir, Sadin; Tekgul, Atakan; Unlu, Cumhur Gokhan; Ocakoglu, Kasim; Dizge, Nadir
    The enhanced biological activity of perovskite type La1-xBaxMnO3 (x = 0.2, 0.3, 0.4) nanoparticle was studied based on antioxidant, antimicrobial, anti-biofilm, bacterial viability inhibition, and DNA cleavage studies. The nanoparticles were prepared by Sol-gel technique and they were analyzed on structure and morphological by XRD and SEM. La0.6Ba0.4MnO3 showed the highest DPPH free radical scavenging activity and iron chelating activity as 67.23% and 46.54%, respectively. All tested lanthanum nanoparticles showed good chemical nuclease activity. C. tropicalis was the most affected species by lanthanum nanoparticles and MIC values were 4 mu g/mL, 8 mu g/mL, and 16 mu g/mL for La0.7Ba0.4MnO3, La0.6Ba0.4MnO3, and La0.8Ba0.2MnO3, respectively. La0.7Ba0.4MnO3 exhibited the highest percentage of biofilm inhibition against P. aeruginosa and S. aureus as 99.78% and 98.38%, respectively. Cell viability assay demonstrated that La0.7Ba0.4MnO3, La0.6Ba0.4MnO3, and La0.8Ba0.2MnO3 showed %100 cell viability inhibition after 30 and 60 min treatment. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.
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    Synthesis, characterization and evaluation of the photochemical properties and photothermal conversion capacities of Mo2CTx-MXene@Fuc nanohybrids
    (Elsevier Science Sa, 2025) Yurt, Fatma; Tuncel, Ayca; Kaya, Gul; Sert, Buse; Ozel, Derya; Harputlu, Ersan; Unlu, Cumhur Gokhan
    Studies on synthesizing MXene hybrid materials continue in medicine, biomedicine, the environment, electronics, and many other fields. MXenes are very remarkable materials for diagnosis, treatment, and theranostic applications in oncology with their hydrophilic structure, large surface area, and biocompatibility. In this study, MAX phase and Mo2CTx MXene syntheses were first carried out and characterized by XRD and HR-TEM. Then, PAH and fucoidan were coated on the MXene surface, respectively, and characterized by FE-SEM, XPS, and Zeta potential methods. Experiments on Mo2CTx-MXene@Fuc nanohybrids have identified their photothermal conversion capacity and photostability, which are crucial for photothermal therapy applications. After calibration of laser devices at 808 and 1064 nm, the nanohybrids' response to laser exposure was monitored, with temperature changes recorded via a thermal camera. Additionally, the photothermal conversion capacity was deduced from heating and cooling durations, while singlet oxygen production efficiency was evaluated using the 1,3-Diphenylisobenzofuran (DPBF) fluorescent probe. These findings underscore the potential of Mo2CTx-MXene@Fuc nanomaterials in photothermal therapy, particularly their efficiency in converting NIR radiation into therapeutic heat.