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Boyko, Yu I. "Structural rearrangement and change of cerium valence in cerium dioxide (CeO2) nanocrystals". Functional materials 23, nr 2 (15.06.2016): 202–5. http://dx.doi.org/10.15407/fm23.02.202.
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Channei, Duangdao, Panatda Jannoey, Auppatham Nakaruk i Sukon Phanichphant. "Photocatalytic Activity of Cu-Doped Cerium Dioxide Nanoparticles". Key Engineering Materials 751 (sierpień 2017): 801–6. http://dx.doi.org/10.4028/www.scientific.net/kem.751.801.
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Pure CeO2 and Cu-doped CeO2 nanoparticles with different doping amounts of Cu in the range of 0.5-2.0 wt.% were synthesized by the combination of homogeneous precipitation and impregnation methods. The effect of Cu on the correlation of structural, optical and photocatalytic properties of CeO2 were studied. The XRD results indicated that phase structures of pure CeO2 and Cu-doped CeO2 nanoparticles were cubic fluorite phase and no other characteristic peaks related to Cu were detected. TEM images revealed that all samples were spherical in shape with the size less than 10 nm. The shift of absorption edge of Cu-doped CeO2 catalysts, corresponding to a decrease of band gap energies from 3.2 to 2.8 eV, was also observed as the amount of Cu dopant increased. The photocatalytic performances of the Cu-doped CeO2 exhibited higher activity than pure CeO2 for photocatalytic degradation of methylene blue under visible light irradiation, and the CeO2 doped with 1.0 wt.% Cu exhibited the highest photocatalytic activity.
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Strobel, Claudia, Martin Förster i Ingrid Hilger. "Biocompatibility of cerium dioxide and silicon dioxide nanoparticles with endothelial cells". Beilstein Journal of Nanotechnology 5 (17.10.2014): 1795–807. http://dx.doi.org/10.3762/bjnano.5.190.
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Cerium dioxide (CeO2) and silicon dioxide (SiO2) nanoparticles are of widespread use in modern life. This means that human beings are markedly exposed to them in their everyday life. Once passing biological barriers, these nanoparticles are expected to interact with endothelial cells, leading to systemic alterations with distinct influences on human health. In the present study we observed the metabolic impact of differently sized CeO2 (8 nm; 35 nm) and SiO2 nanoparticles (117 nm; 315 nm) on immortalized human microvascular (HMEC-1) and primary macrovascular endothelial cells (HUVEC), with particular focus on the CeO2 nanoparticles. The characterization of the CeO2 nanoparticles in cell culture media with varying serum content indicated a steric stabilization of nanoparticles due to interaction with proteins. After cellular uptake, the CeO2 nanoparticles were localized around the nucleus in a ring-shaped manner. The nanoparticles revealed concentration and time, but no size-dependent effects on the cellular adenosine triphosphate levels. HUVEC reacted more sensitively to CeO2 nanoparticle exposure than HMEC-1. This effect was also observed in relation to cytokine release after nanoparticle treatment. The CeO2 nanoparticles exhibited a specific impact on the release of diverse proteins. Namely, a slight trend towards pro-inflammatory effects, a slight pro-thrombotic impact, and an increase of reactive oxygen species after nanoparticle exposure were observed with increasing incubation time. For SiO2 nanoparticles, concentration- and time-dependent effects on the metabolic activity as well as pro-inflammatory reactions were detectable. In general, the effects of the investigated nanoparticles on endothelial cells were rather insignificant, since the alterations on the metabolic cell activity became visible at a nanoparticle concentration that is by far higher than those expected to occur in the in vivo situation (CeO2 nanoparticles: 100 µg/mL; SiO2 nanoparticles: 10 µg/mL).
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Filippova, A. D., A. E. Baranchikov i V. K. Ivanov. "Enzyme-Like Activity of Cerium Dioxide Colloidal Solutions Stabilized with L-Malic Acid". Коллоидный журнал 85, nr 5 (1.09.2023): 668–81. http://dx.doi.org/10.31857/s0023291223600529.
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For the first time, stable aqueous colloidal solutions of cerium dioxide stabilized with L-malic acid have been obtained at ligand : CeO2 molar ratios of 0.2, 0.5, 1.0, and 2.0. Using dynamic light scattering, it has been shown that CeO2 sols are characterized by a narrow monomodal size distribution of aggregates, and the sols remain to be aggregatively stable in a Tris-HCl buffer solution. According to the chemiluminescence analysis of the enzyme-like activity of cerium dioxide sols with respect to hydrogen peroxide, the surface modification of the cerium dioxide particles with malic acid increases the enzyme-like activity of СеО2 up to 4.5 times.
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Stegniy, B. T., O. A. Demchenko, O. M. Korneykov, M. Yu Stegniy, A. Yu Oleshko, O. B. Korneikova, I. V. Korovin, L. P. Babenko i M. Ya Spivak. "Antiviral Effect of Cerium Dioxide Nanoparticles on the Model of the Causative Agent of Bovine Viral Diarrhea". Mikrobiolohichnyi Zhurnal 83, nr 6 (17.12.2021): 65–74. http://dx.doi.org/10.15407/microbiolj83.06.065.
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Cerium dioxide nanoparticles (CeO2) have a wide range of biological properties, including antiviral activity. Preparations based on cerium oxide nanoparticles can be effective against animal RNA viruses, which have the greatest epizootic significance for Ukraine and potentially against human viruses, including SARS-CoV-2. In our studies, we determined the effect of cerium dioxide nanoparticles on bovine viral diarrhea virus (BVDV), a pestivirus that is the etiological agent of bovine viral diarrhea. To determine the antiviral efficacy of CeO2, a cytopathogenic strain of BVDV “BK-1” was used as an etiological agent of bovine viral diarrhea, which induces a cytopathic effect on cow embryo lungs (CEL) cell culture. When evaluating the antiviral efficacy of CeO2, it was determined that the MPC for CEL cell culture is 0.057 μg/cm3, and the CC50 is 0.077 μg/cm3. The antiviral activity of CeO2 was evaluated by the IC50 index, which was 0.036 μg/cm3 and the selectivity index, which after co-administration of CeO2 with BVDV was 2.14. There was a decrease in the titer of infectious activity of the virus during treatment with CeO2 by 2.09 lg TCD50/cm3.
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Ahire, Satish Arvind, Ashwini Ashok Bachhav, Thansingh Bhavsing Pawar, Arun Vitthal Patil, Swapnil Sampatrao Shendge i Prashant Bhimrao Koli. "Green Synthesis of Ceria Nanoparticles Using Azadirachta Indica Plant Extract: Characterization, Gas Sensing and Antibacterial Studies". Material Science Research India 18, nr 3 (30.12.2021): 285–97. http://dx.doi.org/10.13005/msri/180304.
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In the present investigation we have fabricated the cerium dioxide (CeO2) nanoparticles by green route. While preparing the cerium dioxide nanoparticles by co-precipitation method, Neem leaf extract mixed into the precursor of cerium. The synthesized nanoparticles of CeO2 were used for the preparation of thick film sensor by using screen printing strategy. The fabricated CeO2 sensor was characterized by XRD, SEM, EDS and TEM techniques. The structural characteristics investigated by x-ray diffraction technique (XRD). XRD confirms the formation of cubic lattice of CeO2 material. The surface, texture, porosity characteristics were investigated from SEM analysis, while chemical composition of the material was analysed by EDS technique. The transmission electron microscopy (TEM) confirms the formation cubic lattice of the cerium dioxide material. The thickness of the films was calculated from mass difference method, the prepared film sensors belong to thick region. The fabricated material CeO2 sensor was applied as gas sensor to sense the gases such as LPG, petrol vapors (PV), toluene vapors (TV) and CO2. The CeO2 sensor showed excellent gas response for LPG and PV, nearly 93.20 % and 78.23 % gas response. The rapid response and recovery of the prepared sensors was observed at the tested gases. CeO2 material also employed for antibacterial study at several pathogenic organism such as pseudomonas, staphylococcus aureus and salmonella typhae. From antibacterial study it was observed that the material is capable of inhibiting the growth of these pathogenic microbes.
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Huang, Hui, i Zhong Cheng Guo. "Preparation and Characterization of Conductive Polyaniline/Cerium Dioxide Composites". Materials Science Forum 663-665 (listopad 2010): 686–89. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.686.
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Conductive polyaniline/cerium dioxide (PANI/CeO2) composites have been synthesized by in-situ polymerization of aniline in the presence of CeO2 nanoparticles. The structure and thermal stability of obtained composites were characterized by Fourier-transform infrared spectra (FTIR), Fourier-transform Raman spectra (FT-Raman), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results showed that PANI and CeO2 nanoparticles were not simply blended, and a strong interaction existed at the interface of CeO2 and PANI. In the PANI/CeO2 composite, the degree crystallinity of PANI increased and diffraction pattern of CeO2 was amorphous. And that the composites were more thermally stable than that of the pure PANI. Electrical conductivity measurements indicated that the conductivity of PANI/CeO2 composites was much higher than that of the pure PANI and the maximum conductivity obtained was 11.68 S/cm at 17.5 wt% of CeO2.
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Kim, Young-Soo, Jin-Kyu Lee, Jae-Hoon Ahn, Eun-Kyung Park, Gil-Pyo Kim i Sung-Hyeon Baeck. "Fabrication of Mesoporous Cerium Dioxide Films by Cathodic Electrodeposition". Journal of Nanoscience and Nanotechnology 7, nr 11 (1.11.2007): 4198–201. http://dx.doi.org/10.1166/jnn.2007.109.
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Mesoporous cerium dioxide (Ceria, CeO2) thin films have been successfully electrodeposited onto ITO-coated glass substrates from an aqueous solution of cerium nitrate using CTAB (Cetyltrimethylammonium Bromide) as a templatingagent. The synthesized films underwent detailed characterizations. The crystallinity of synthesized CeO2 film was confirmed by XRD analysis and HR-TEM analysis, and surface morphology was investigated by SEM analysis. The presence of mesoporosity in fabricated films was confirmed by TEM and small angle X-ray analysis. As-synthesized film was observed from XRD analysis and HR-TEM image to have well-crystallized structure of cubic phase CeO2. Transmission electron microscopy and small angle X-ray analysis revealed the presence of uniform mesoporosity with a well-ordered lamellar phase in the CeO2 films electrodeposited with CTAB templating.
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Deval, Gaëlle, Sonja Boland, Thierry Fournier i Ioana Ferecatu. "On Placental Toxicology Studies and Cerium Dioxide Nanoparticles". International Journal of Molecular Sciences 22, nr 22 (12.11.2021): 12266. http://dx.doi.org/10.3390/ijms222212266.
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The human placenta is a transient organ essential for pregnancy maintenance, fetal development and growth. It has several functions, including that of a selective barrier against pathogens and xenobiotics from maternal blood. However, some pollutants can accumulate in the placenta or pass through with possible repercussions on pregnancy outcomes. Cerium dioxide nanoparticles (CeO2 NPs), also termed nanoceria, are an emerging pollutant whose impact on pregnancy is starting to be defined. CeO2 NPs are already used in different fields for industrial and commercial applications and have even been proposed for some biomedical applications. Since 2010, nanoceria have been subject to priority monitoring by the Organization for Economic Co-operation and Development in order to assess their toxicity. This review aims to summarize the current methods and models used for toxicology studies on the placental barrier, from the basic ones to the very latest, as well as to overview the most recent knowledge of the impact of CeO2 NPs on human health, and more specifically during the sensitive window of pregnancy. Further research is needed to highlight the relationship between environmental exposure to CeO2 and placental dysfunction with its implications for pregnancy outcome.
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Lukin, Anton V., Galina I. Lukina, Alexey V. Volkov, Alexander E. Baranchikov, Vladimir K. Ivanov i Alexey A. Prokopov. "Morphometry Results of Formed Osteodefects When Using Nanocrystalline CeO2 in the Early Stages of Regeneration". International Journal of Dentistry 2019 (26.12.2019): 1–9. http://dx.doi.org/10.1155/2019/9416381.
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This paper studies of the use of nanocrystalline cerium dioxide with artificially formed bone tissue defects. The results of morphometry confirmed the antialterative effect in the early stages of the reparative process of damaged bone tissue. When using calcium hydroxide with nanodispersed cerium dioxide, the nature of osteogenesis should be characterized as activated. In case of damage to the dentin of the roots of the teeth, dentinogenesis in presence of CeO2 occurs with the formation of a combined dentin and bone regenerates. Little or no studies of dentinogenesis in presence of CeO2 were performed by other researchers.
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Hadi, Abdul, Iskandar Idris Yaacob i Cheah Seok Gaik. "Synthesis of Nanocrystalline CeO2 Using Mechanochemical Method: The Effect of Milling Time on the Particle Size". Materials Science Forum 517 (czerwiec 2006): 105–10. http://dx.doi.org/10.4028/www.scientific.net/msf.517.105.
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Nanocrystalline cerium dioxide (CeO2) has been successfully synthesized by mechanochemical technique at 12, 24, 36, 48 and 60 hours milling times. The starting materials, hydrated cerium carbonate and sodium hydroxide, were mixed in a weight ratio of 4:1 and were milled in a planetary ball mill with ball to powder ratio of 10:1. The high energy impact forces provided by the milling media caused collision of starting materials and allowed the chemical reaction to occur thus produced nanocrystalline cerium dioxide. The products were characterized using a battery of characterization methods, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and gas adsorption-desorption measurement. The nanocrystalline CeO2 with 6.7 nm of crystallite size and specific surface area of 66.66 m2/g was obtained when the sample was milled for 60 hrs and they annealed in air at 350 oC. The result showed that the crystallinity of nanocrystalline CeO2 decreased with increasing milling time.
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Liu, Xichen, Jianhua Zhang, Hao Zhang, Can Chen i Dongzhi Zhang. "Enhanced Sensing Performance of Electrospun Tin Dioxide Nanofibers Decorated with Cerium Dioxide Nanoparticles for the Detection of Liquefied Petroleum Gas". Chemosensors 10, nr 12 (23.11.2022): 497. http://dx.doi.org/10.3390/chemosensors10120497.
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Tin dioxide (SnO2) nanofibers and cerium dioxide (CeO2) nanoparticles were prepared by electrospinning and hydrothermal methods, respectively. The morphology and structure of the synthesized SnO2/CeO2 samples were characterized by a variety of methods. The gas-sensing properties of the SnO2/CeO2 sensor were investigated for liquefied petroleum gas (LPG) detection at room temperature. Compared with pure SnO2 nanofibers, the SnO2/CeO2 composite sensor showed a much higher response and shorter response time for LPG sensing after doping with CeO2 nanoparticles. Furthermore, the SnO2/CeO2 composite sensor had better resistance to interference from humidity than the pure SnO2 sensor. The significantly enhanced sensing performance of the SnO2/CeO2 composite sensor for LPG can be attributed to the modification with CeO2 to increase oxygen vacancies and form a heterostructure with SnO2 nanofibers. Meanwhile, the LPG detection circuit was built to realize real-time concentration display and alarm for practical applications.
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Jiang, Keyu, Leyuan Dong, Qi Shen, Wei Wu, Xue Wu, Jian Mei i Shijian Yang. "Chlorobenzene Oxidation over Phosphotungstic-Acid-Coated Cerium Oxide: Synergistic Effect of Phosphotungstic and Cerium Oxide and Inhibition Mechanism of Sulfur Dioxide". Sustainability 16, nr 6 (7.03.2024): 2245. http://dx.doi.org/10.3390/su16062245.
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Ce–based catalysts exhibit a poor stability and activity in chlorinated volatile organic compound (Cl–VOC) oxidation due to their rapid Cl poisoning. Herein, phosphotungstic acid (HPW) was coated on CeO2 to improve its activity and stability for chlorobenzene (CB) oxidation. The HPW coating not only promoted CB adsorption onto CeO2, but also provided Brønsted acid sites to CeO2 for Cl species removal as HCl, thus avoiding Cl poisoning. Hence, a synergistic effect of CeO2 and HPW on HPW/CeO2 was observed, resulting in superior CB oxidation activity and stability. Additionally, to improve the sulfur resistance of the catalyst, the inhibition mechanism of SO2 on CB oxidation by HPW/CeO2 was explored. HPW/CeO2 was prone to sulfation due to the formation of Ce2(SO4)3 from the reaction of SO2 and CeO2. Thus, the oxidation ability of HPW/CeO2; the amount of adsorption sites for CB adsorption; and the amounts of Ce4+ bonded with O2−, lattice oxygen species, and adsorbed oxygen species were decreased by SO2. Meanwhile, SO2 competed with CB for the adsorption sites on HPW/CeO2. Therefore, CB oxidation by HPW/CeO2 was remarkably restrained by SO2. The present work promotes further work on Cl–VOC removal by Ce-based catalysts for anti-SO2 poisoning modification in the future.
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Ishraq Ahmed Shakir, Zainab Hamzah Baqi i ) Zainab Shakir Naser. "Preparation Of Cerium Dioxide Nps And Its Adoption In Biomedical Applications". Journal of the College of Basic Education 30, nr 125 (4.10.2024): 41–52. http://dx.doi.org/10.35950/cbej.v30i125.12186.
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A simple chemical approach was used to synthesize cerium dioxide (CeO2) NPss (NPs). UV-Visible , (FTIR), (XRD) and (SEM) were used to characterize the CeO2 NPs. It was found that band gap of the CeO2 NPs (Eg = 4.1 electron volt) was enlarged as compared to bulk ceria (Eg = 3.19 electron volt) based on UV-Vis analysis. SEM scans indicated spherical-shaped particles with a diameter of 47.68 nm, which were verified by FTIR data at 594 cm-1. Additionally, the generated CeO2NPs' antibacterial and antifungal efficacies were assessed, and the results showed that CeO2 NPs had both antibacterial and antifungal activity. Activities had varied values because the two groups' cell walls and membranes had distinct compositions.
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Akopov, F. A. "Cerium dioxide-based high temperature air heaters". NOVYE OGNEUPORY (NEW REFRACTORIES), nr 3 (30.04.2019): 40–43. http://dx.doi.org/10.17073/1683-4518-2019-3-40-43.
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The possibility of developing electric heaters based on cerium dioxide for air with an operating range of 300‒2500 K is discussed. The influence of various factors on the electrical conductivity of CeO2 ceramics has been investigated. The main physicochemical and ceramic properties of ceramics are characterized. Ill. 2. Ref. 8.
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Chaudhary, Archana, Mohd Quasim Khan, Rais Ahmad Khan, Ali Alsalme, Khursheed Ahmad i Haekyoung Kim. "Fabrication of CeO2/GCE for Electrochemical Sensing of Hydroquinone". Biosensors 12, nr 10 (8.10.2022): 846. http://dx.doi.org/10.3390/bios12100846.
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Hydroquinone is a widely used derivative of phenol which has a negative influence on human beings and the environment. The determination of the accurate amount of hydroquinone is of great importance. Recently, the fabrication of an electrochemical sensing device has received enormous attention. In this study, we reported on the facile synthesis of cerium dioxide (CeO2) nanoparticles (NPs). The CeO2 NPs were synthesized using cerium nitrate hexahydrate as a precursor. For determining the physicochemical properties of synthesized CeO2 NPs, various advanced techniques, viz., powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS), were studied. Further, these synthesized CeO2 NPs were used for the modification of a glassy carbon electrode (CeO2/GCE), which was utilized for the sensing of hydroquinone (HQ). A decent detection limit of 0.9 µM with a sensitivity of 0.41 µA/µM cm2 was exhibited by the modified electrode (CeO2/GCE). The CeO2/GCE also exhibited good stability, selectivity, and repeatability towards the determination of HQ.
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Baqer, Anwar Ali, Khamirul Amin Matori, Naif Mohammed Al-Hada, Abdul Halim Shaari, Elias Saion i Josephine Liew Ying Chyi. "Synthesis, Structural and Optical Properties of Cerium Oxide Nanoparticles Prepared by Thermal Treatment Method". Solid State Phenomena 268 (październik 2017): 132–37. http://dx.doi.org/10.4028/www.scientific.net/ssp.268.132.
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A sample thermal treatment technique was utilised to synthesis cerium dioxide (CeO2) nanoparticles, using cerium (111) nitrate as a precursor, Polyvinylpyrrolidone as a capping agent, and deionized water as a solvent. The product underwent calcination treatment of 500, 550, 600, and 650 1C to crystallize the nanoparticles and to remove organic compounds. It was verified by XRD that by varying the calcination temperature, the cubic fluorite structure of CeO2 nanoparticles with pure products was achieved. Furthermore, the crystal sizes of the CeO2 nanoparticles were assessed to be 4 nm for the lowest calcination temperature and 23 nm for the highest calcination temperature. The FESEM micrographs of the CeO2 nanoparticles revealed a structure of CeO2 nanospherical that exhibited a tendency to amalgamate at higher calcination temperatures. The optical characteristics that were evaluated with the help of a UV-Vis spectrophotometer indicated a decrease in the band gap energy with an increase in calcination temperature as a result of the increase in the crystal sizes.
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Frost, Mungo, John D. Lazarz, Abraham L. Levitan, Vitali B. Prakapenka, Peihao Sun, Sergey N. Tkachev, Hong Yang, Siegfried H. Glenzer i Arianna E. Gleason. "High Pressure Brillouin Spectroscopy and X-ray Diffraction of Cerium Dioxide". Materials 14, nr 13 (1.07.2021): 3683. http://dx.doi.org/10.3390/ma14133683.
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Simultaneous high-pressure Brillouin spectroscopy and powder X-ray diffraction of cerium dioxide powders are presented at room temperature to a pressure of 45 GPa. Micro- and nanocrystalline powders are studied and the density, acoustic velocities and elastic moduli determined. In contrast to recent reports of anomalous compressibility and strength in nanocrystalline cerium dioxide, the acoustic velocities are found to be insensitive to grain size and enhanced strength is not observed in nanocrystalline CeO2. Discrepancies in the bulk moduli derived from Brillouin and powder X-ray diffraction studies suggest that the properties of CeO2 are sensitive to the hydrostaticity of its environment. Our Brillouin data give the shear modulus, G0 = 63 (3) GPa, and adiabatic bulk modulus, KS0 = 142 (9) GPa, which is considerably lower than the isothermal bulk modulus, KT0∼ 230 GPa, determined by high-pressure X-ray diffraction experiments.
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Andrievskaya, Olena, Oksana Kornienko, Oleksandr Bykov, Olga Chudinovich i Larysa Spasonova. "The interaction between cerium dioxide, lanthanum and europium oxides at 1500°C". Processing and Application of Ceramics 15, nr 1 (2021): 32–39. http://dx.doi.org/10.2298/pac2101032a.
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Materials based on CeO2-La2O3-Eu2O3 and La2O3-Eu2O3 systems are promising candidates for a wide range of applications, but the phase relationship has not been studied systematically previously. The phase relations in the CeO2-La2O3-Eu2O3 ternary system at 1500?C and binary La2O3-Eu2O3 system at 1600-1500?C were studied in air by X-ray diffraction (XRD) investigation in the overall concentration range. The isothermal section of the phase diagram for the CeO2-La2O3-Eu2O3 system has been constructed. It was established that in the ternary CeO2-La2O3-Eu2O3 system there exist fields of solid solutions based on hexagonal (A) modification of La2O3, cubic modification of CeO2 with fluorite-type structure (F), cubic (C) and monoclinic (B) modification Eu2O3. It was established that in the binary La2O3-Eu2O3 system there exist fields of solid solutions based on hexagonal (A) modification of La2O3 and monoclinic (B) modification Eu2O3. The phases were separated by two-phase fields (A+B). The refined lattice parameters of the unit cells for solid solutions and microstructures of the definite field of compositions for the systems were determined.
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Pugachevskii, M. A., V. A. Mamontov, A. A. Kryukov, S. A. Dodonova, E. B. Artyushkova i V. A. Pikkiev. "Protective Properties of Ablated Cerium Oxide Nanoparticles for Cell Cultures under Conditions of Oxidative Stress under Ultraviolet and Ionizing Irradiation". Proceedings of the Southwest State University. Series: Engineering and Technology 13, nr 4 (18.01.2024): 139–51. http://dx.doi.org/10.21869/2223-1528-2023-13-4-139-151.
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Purpose. Study of the protective properties of ablated cerium oxide nanoparticles for cell cultures in an oxidative reaction under ultraviolet and ionizing irradiation.Methods. Cerium dioxide nanoparticles with high antioxidant activity were obtained using laser ablation. Atomic force microscopy was used to characterize ablated cerium dioxide nanoparticles and cells incubated with cerium dioxide nanoparticles. The protective properties of cerium dioxide nanoparticles were studied after 0 (without incubation), 6and 24-hour incubation using the colorimetric MTT test method.Results. Using laser ablation, cerium oxide nanoparticles with a maximum size of up to 50 nm were obtained. The resulting nanoparticles were incubated with BJ TERT cell lines for 6 and 24 hours. The samples were subjected to ultraviolet (UV) and ionizing irradiation in order to reveal the protective properties of CeO2 nanoparticles. Based on the results of the MTT test, it was found that incubation with cerium dioxide nanoparticles has a pronounced protective effect on the BJ TERT cell line. After UV irradiation, 6-hour and 24-hour incubation of cerium oxide nanoparticles with cell culture provides 15±5% and 20±5% more cell survival, respectively, than without particles. After ionizing radiation, the percentage of survival of cells incubated for 24 hours with cerium nanoparticles also increases by 20±5%.Conclusion. This work shows that ablated cerium dioxide nanoparticles have a protective effect on healthy BJ TERT cells. The work shows that cerium oxide nanoparticles are promising antioxidants that can provide a protective effect for cell cultures from ultraviolet and ionizing radiation.
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Garcia, Isadora Martini, Vicente Castelo Branco Leitune, Antonio Shigueaki Takimi, Carlos Pérez Bergmann, Susana Maria Werner Samuel, Mary Anne Melo i Fabrício Mezzomo Collares. "Cerium Dioxide Particles to Tune Radiopacity of Dental Adhesives: Microstructural and Physico-Chemical Evaluation". Journal of Functional Biomaterials 11, nr 1 (11.02.2020): 7. http://dx.doi.org/10.3390/jfb11010007.
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The insufficient radiopacity of dental adhesives applied under composite restorations makes the radiographic diagnosis of recurrent caries challenging. Consequently, the misdiagnosis may lead to unnecessary replacement of restorations. The aims of this study were to formulate experimental dental adhesives containing cerium dioxide (CeO2) and investigate the effects of different loadings of CeO2 on their radiopacity and degree of conversion for the first time. CeO2 was characterized by X-ray diffraction analysis, Fourier transforms infrared spectroscopy, and laser diffraction for particle size analysis. Experimental dental adhesives were formulated with CeO2 as the inorganic filler with loadings ranging from 0.36 to 5.76 vol.%. The unfilled adhesive was used as a control. The studied adhesives were evaluated for dispersion of CeO2 in the polymerized samples, degree of conversion, and radiopacity. CeO2 presented a monoclinic crystalline phase, peaks related to Ce-O bonding, and an average particle size of around 16 µm. CeO2 was dispersed in the adhesive, and the addition of these particles increased the adhesives’ radiopacity (p < 0.05). There was a significant decrease in the degree of conversion with CeO2 loadings higher than 1.44 vol.%. However, all materials showed a similar degree of conversion in comparison to commercially available adhesives. CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dental adhesives.
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Solovyeva, A. E. "The defects of structural and phase transformations in polycrystalline cerium dioxide under heating in vacuum and in air". NOVYE OGNEUPORY (NEW REFRACTORIES), nr 7 (30.11.2023): 42–51. http://dx.doi.org/10.17073/1683-4518-2023-7-42-51.
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Structural changes in cerium dioxide, when heated in vacuum in the range of 25‒1600 °C, in air in the range of 25‒1500 °C, and during successive annealing in the range of 1600‒2100 °C in air, followed by quenching in water, were studied. In the crystal lattice of CeO2‒х, the F → F1 phase transformation in vacuum proceeds in the range of 1100‒1600 °C; additionally, at 1200 °C, X-ray lines of the C-type Ce2O3 phase appear. The thermal expansion coefficient of phases of the fluorite type F and F1 in the range of 25‒1500 °C in air, as well as phases of the fluorite type F, F1 and type C Ce2O3 in the range of 25‒1600 °C are determined in vacuum and their dependence on the change in the oxygen content in the CeO2‒х crystal lattice was found. The kinetic conditions for reduction of cerium dioxide in vacuum and oxidation in air are different. The cubic structure of the fluorite type F CeO2‒х, when the samples are heated in air, is preserved up to 1800 °C with the content of anionic vacancies, at 1900 °C the transformation F → F1 occurs. The formation of loops, edge and screw dislocations in the structure of cerium dioxide grains after annealing of samples in the range of 1900‒2100 °C in air were discovered for the first time. The decomposition of the structure F1 into cerium oxide phases of types F and C proceeds at 2100 °C along the height and boundaries of screw dislocations. It was found that fragments of the C-type phase of cerium oxide are located on loops along the height of screw dislocations, which indicates the movement and evaporation of these fragments. When the samples are oxidized at 1600 °C in air, the black-colored C Ce2O3‒х phase in a gradient of different concentrations moves along certain trajectories to opposite ones. grain boundaries, abuts against dislocation loops, bends them, and oxidizes to phases F1 and F. In the structure of polycrystalline cerium dioxide, when heated in vacuum and in air, certain concentrations of defects control phase transformations.
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Serafin, Jarosław, i Jordi Llorca. "Nanoshaped Cerium Oxide with Nickel as a Non-Noble Metal Catalyst for CO2 Thermochemical Reactions". Molecules 28, nr 7 (24.03.2023): 2926. http://dx.doi.org/10.3390/molecules28072926.
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Four different nanoshapes of cerium dioxide have been prepared (polycrystals, rods, cubes, and octahedra) and have been decorated with different metals (Ru, Pd, Au, Pt, Cu, and Ni) by incipient wetness impregnation (IWI) and ball milling (BM) methods. After an initial analysis based on oxygen consumption from CO2 pulse chemisorption, Ni-like metal, and two forms of CeO2 cubes and rods were selected for further research. Catalysts were characterized using the Brunauer-Emmett-Teller formula (BET), X-ray spectroscopy (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV–visible spectrophotometry (UV-Vis), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H2-TPR) and CO2 pulse chemisorption, and used to reduce of CO2 into CO (CO2 splitting). Adding metals to cerium dioxide enhanced the ability of CeO2 to release oxygen and concomitant reactivity toward the reduction of CO2. The effect of the metal precursor and concentration were evaluated. The highest CO2 splitting value was achieved for 2% Ni/CeO2-rods prepared by ball milling using Ni nitrate (412 µmol/gcat) and the H2 consumption (453.2 µmol/gcat) confirms the good redox ability of this catalyst.
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Baranchikov, Alexander E., Mikhail I. Razumov, Svetlana V. Kameneva, Madina M. Sozarukova, Tatiana S. Beshkareva, Arina D. Filippova, Daniil A. Kozlov, Olga S. Ivanova, Alexander B. Shcherbakov i Vladimir K. Ivanov. "Facile Synthesis of Stable Cerium Dioxide Sols in Nonpolar Solvents". Molecules 27, nr 15 (7.08.2022): 5028. http://dx.doi.org/10.3390/molecules27155028.
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A method is proposed for the preparation of stable sols of nanocrystalline cerium dioxide in nonpolar solvents, based on surface modification of CeO2 nanoparticles obtained by thermal hydrolysis of concentrated aqueous solutions of ammonium cerium(IV) nitrate with residues of 2-ethylhexanoic and octanoic acids. The synthesis was carried out at temperatures below 100 °C and did not require the use of expensive and toxic reagents. An assessment of the radical-scavenging properties of the obtained sols using the superoxide anion-radical neutralization model revealed that they demonstrate notable antioxidant activity. The results obtained indicate the potential of the nanoscale cerium dioxide sols in nonpolar solvents to be used for creating nanobiomaterials possessing antioxidant properties.
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Vangelista, Silvia, Rossella Piagge, Satu Ek, Tiina Sarnet, Gabriella Ghidini i Alessio Lamperti. "Atomic Layer Deposition of Cerium Dioxide Film on TiN and Si Substrates: Structural and Chemical Properties". MRS Advances 2, nr 52 (2017): 3005–10. http://dx.doi.org/10.1557/adv.2017.404.
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ABSTRACTCerium dioxide (CeO2) thin films were deposited by atomic layer deposition (ALD) on both Si and TiN substrates. The ALD growth produces CeO2 cubic polycrystalline films on both substrates. However, the films show a preferential orientation along <200> crystallographic direction for CeO2/Si or <111> for CeO2/TiN. In correspondence, we measure a relative concentration of Ce3+ equals to 22.0% in CeO2/Si and around 18% in CeO2/TiN, by X-ray photoelectron spectroscopy. Such values indicate the presence of oxygen vacancies in the films. Our results underline the films differences and similarities between ALD-deposited CeO2 either on Si or TiN substrates, thus extending the knowledge on the CeO2 structural and chemical properties.
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Hudda, Komal, Barkha Rathee, Mukhan Wati, Sweety Ranga i Rajdeep Tyagi. "Some Applications of CeO2 Nanoparticles". Oriental Journal Of Chemistry 39, nr 3 (30.06.2023): 684–93. http://dx.doi.org/10.13005/ojc/390319.
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Various properties of cerium oxide (Ceria, CeO2) have been widely used in recent times. This article aims at discussing some fundamental properties of ceria, its application due to oxygen vacancies in its structure, its effects due to nano-size, synthesis strategy to give it a structure with diverse applications. Some basic applications of ceria-based structure have been reviewed. Ceria nanoparticles are used in catalytic converters in the automotive industries to convert harmful carbon monoxide to less harmful carbon dioxide, semiconductor industries uses it as fine abrasive and polishing agent, it can light production in mantles of gas lanterns where cerium oxide generates a yellowish white colour. Certain probable toxic effects and challenges in controllable synthesis of nanomaterials for its applications have been reviewed.
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Lee, Doohwan, Seung Hee Hong i Eunyoung Yu. "Modulation of the Intrinsic Radical Scavenging Properties of CeO2 Nanoparticles". ECS Meeting Abstracts MA2024-01, nr 36 (9.08.2024): 2097. http://dx.doi.org/10.1149/ma2024-01362097mtgabs.
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Cerium dioxide (CeO2) has been extensively investigated as a scavenger of reactive oxygen radicals, particularly in the context of polymer electrolyte membrane fuel cells. This study focuses on elucidating the impact of exposed crystal facets of CeO2 nanoparticles on their radical scavenging activities. The manipulation of crystal shapes, including rod, cube, and octahedral forms, allows for controlled variation of the exposed crystal facets of CeO2 NPs. Characterization of the resulting CeO2 NPs is conducted using XRD, Raman spectroscopy, XPS, BET, and Fenton’s reaction. The research reveals that the intrinsic radical scavenging activity of CeO2 NPs can be effectively modulated by controlling their exposed crystal facets.
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Goodhead, Rhys M., Blair D. Johnston, Paula A. Cole, Mohammed Baalousha, David Hodgson, Taisen Iguchi, Jamie R. Lead i Charles R. Tyler. "Does natural organic matter increase the bioavailability of cerium dioxide nanoparticles to fish?" Environmental Chemistry 12, nr 6 (2015): 673. http://dx.doi.org/10.1071/en15003.
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Environmental context Nanoparticles are present in growing volumes of consumer products and are suspected to be released into the environment at detectable levels. We focus on cerium dioxide nanoparticles and investigate their availability to fish from the water column, where we found increasing concentrations of natural organic material increased the ceria measured in the fish gills. This complex interaction between nanoparticle behaviour and uptake from environmentally relevant test systems is significantly understudied. Abstract Natural organic colloids affect the fate and behaviour of nanoparticles in the aquatic environment but how these interactions affect the bioavailability of nanoparticles to organisms is a major knowledge gap in risk-assessment analysis. Here, we investigated interactions of citrate-coated cerium dioxide (CeO2) nanoparticles with fulvic acids, representing natural organic matter, and assessed their bioavailability to fish (common carp, Cyprinus carpio) exposed chronically (32days) via the water. We show a fulvic acid concentration-related enhancement in the uptake of cerium (Ce) into gill tissues, with some evidence for an enhanced Ce uptake also into kidney and brain tissues in the presence of fulvic acids, but with more variable responses. We present evidence for differences in the aggregation behaviour for CeO2 nanoparticles in the different exposure scenarios, with reduced CeO2 particle aggregate size with citrate coating and fulvic acids, as determined from dynamic light scattering. We highlight that multiple analytical approaches are essential for understanding the dynamic nature of the particles and also that interpretations on measured particle sizes and characteristics may differ depending on the technique(s) employed. We conclude that conditions in natural waters are likely to play a fundamental role in affecting bioavailability and thus potential biological effects of CeO2 particles.
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Pecoraro, Roberta, Elena Maria Scalisi, Stefania Indelicato, Martina Contino, Giuliana Coco, Ilenia Stancanelli, Fabiano Capparucci, Roberto Fiorenza i Maria Violetta Brundo. "Toxicity of Titanium Dioxide–Cerium Oxide Nanocomposites to Zebrafish Embryos: A Preliminary Evaluation". Toxics 11, nr 12 (6.12.2023): 994. http://dx.doi.org/10.3390/toxics11120994.
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The widespread use of metal nanoparticles in different fields has raised many doubts regarding their possible toxicity to living organisms and the accumulation and discharge of metals in fish species. Among these nanoparticles, titanium dioxide (TiO2) and cerium oxide (CeO2) nanoparticles have mainly been employed in photocatalysis and water depuration. The aim of this research was to evaluate the potential toxic effects, after a co-exposure of TiO2-3%CeO2 nanoparticles, on zebrafish development, using an acute toxicity test. Increasing concentrations of TiO2-3%CeO2 nanoparticles were used (0.1-1-10-20 mg/L). The heartbeat rate was assessed using DanioscopeTM software (version 1.2) (Noldus, Leesburg, VA, USA), and the responses to two biomarkers of exposure (Heat shock proteins-70 and Metallothioneins) were evaluated through immunofluorescence. Our results showed that the co-exposure to TiO2-3%CeO2 nanoparticles did not affect the embryos’ development compared to the control group; a significant difference (p < 0.05) at 48 hpf heartbeat for the 1, 10, and 20 mg/L groups was found compared to the unexposed group. A statistically significant response (p < 0.05) to Heat shock proteins-70 (Hsp70) was shown for the 0.1 and 1 mg/L groups, while no positivity was observed in all the exposed groups for Metallothioneins (MTs). These results suggest that TiO2-3%CeO2 nanocomposites do not induce developmental toxicity; instead, when considered separately, TiO2 and CeO2 NPs are harmful to zebrafish embryos, as previously shown.
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Mihara, Takeshi, Hiroaki Abe, Takeo Iwai, Takeshi Sonoda i Eiichi Wakai. "Microstructural Evolution in Cerium Dioxide Irradiated with Heavy Ions at High Temperature". Advanced Materials Research 26-28 (październik 2007): 929–32. http://dx.doi.org/10.4028/www.scientific.net/amr.26-28.929.
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Cerium dioxide (CeO2) is a well-studied oxide because of its technological applications, such as a major component in the catalysts, stable capacitors and so on. CeO2 with a cubic fluorite structure is also expected as the material for simulating behaviors of uranium dioxide under energetic particle irradiation, which leads high burn-up structure attributable to pressure increase in fuel cladding tubes. In this work, the stability of crystal structure and surface morphology change in CeO2 will be clarified. Polycrystalline samples were irradiated with 300 keV Xe+, 18 MeV I5+, 350 keV O+ and 12 MeV O3+ ions at temperatures from 370 to 1000 K. Microstructural evolutions was investigated with Scanning electron microscopy, Raman Spectroscopy and X-ray diffractometry. Irradiation effects at high temperature were observed as surface etching and resulting bubble formation, however blistering was not detected. Raman spectra and diffraction data indicates diffusion of oxygen vacancies is sufficient at 900 K and above.
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Molina Lozano, Alberto, i Maria Teresa Cortes Montañez. "Preliminary Study of Photoelectrochemical Properties of Electrosyntetized Cerium Dioxide (CeO2) to Pollutant Treatment". ECS Meeting Abstracts MA2022-01, nr 51 (7.07.2022): 2380. http://dx.doi.org/10.1149/ma2022-01512380mtgabs.
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1. Introduction In this work a systematic procedure to synthetize of cerium dioxide and evaluation and its photoelectrochemical properties for dye degradation in aqueous media is shown. First, electrochemical synthesis of CeO2 methodology is presented as function of annealing temeprature and concentration of Ce3+ precursors in the plating. Next, Raman spectra and FTIR analysis were presented to evaluate structural properties of films. Lineal sweep voltammetry (LSV) and chronoamperometry (CA) results are shown to evaluate the photocurrent and its stability of CeO2 and finally all the results were analyzed in function of excitons production, charge separation and recombination phenomena. 2. Methodology 2.1. Electrochemical synthesis of CeO2 First, cerium hydroxide (Ce(OH)3) was obtained from a CeCl3.7H2O solution (5 and 25 mM) with 0,05 M of NaNO3 as support electrolyte by applying of a constant potential of -1,2 V vs AgCl during 300 s to an FTO electrode (1,3 x 0,6 cm). A reference electrode (Ag/AgCl 3,0 M and a Pt wire as a counter electrode were used in the electrochemical cell connected to a potenciostat-galvanostat AUTOLAB N65 Series. After deposition of cerium hydroxide form, the FTO substrates were alienated at different temperatures (200 – 700 oC) for 1 hour to obtain the oxide cerium form. Finally, FTO photoelectrodes were dried with air and stored at room temperature. 2.2. Photoelectrochemical characterization of CeO2 films LSV and CA were used to evaluate the photo-response and stability of produced photocurrent of CeO2 photoanodes. In the LSV experiment, a range of potential from +0,5 V to 1,2 V was used with a sweep of 10 mV/s. Meanwhile, a bias potential of +1,2 V during 300 s with light-dark cycles of 30 s was used in CA experiments. A system of three electrode (FTO-CeO2 as a working electrode, Ag/AgCl 3,0 M and a Pt wire) were used in an electrochemical with a quartz window. The cell was irradiated with a light source of 100 mW/cm2. The solution of the electrochemical cell was Na2SO4 0,1 M. 3. Results Electrochemical measurements show that there is a great influence in the temperature treatment to obtain high photocurrent using CeO2 photoanodes. Besides, CeO2 increase its photoelectroactivity when small concentration of Ce3+ precursor is used in the electrochemical formation of hydroxide. This could be attributed to a decrease of size particle and therefore a favorable change of band gap of CeO2. Stability of photocurrent of CeO2 photoelectrode changes slowly across the time this process could be product of electronic saturation in the process of charge separation or structural changes during the photoelectrocatalytic process due to applying of potential bias. 4. REFERENCES (1) Ma, R.; Zhang, S.; Wen, T.; Gu, P.; Li, L.; Zhao, G.; Niu, F.; Huang, Q.; Tang, Z.; Wang, X. A Critical Review on Visible-Light-Response CeO2-Based Photocatalysts with Enhanced Photooxidation of Organic Pollutants. Catalysis Today 2019, 335, 20–30. https://doi.org/10.1016/j.cattod.2018.11.016. (2) Liu, Z.; Guo, S.; Hong, C.; Xia, Z. Synthesis and Photocatalytic Properties of CeO2 Nanocubes. Journal of Materials Science: Materials in Electronics 2016, 27 (2), 2146–2150. https://doi.org/10.1007/s10854-015-4004-1. (3) Muñoz-Batista, M. J.; Gómez-Cerezo, M. N.; Kubacka, A.; Tudela, D.; Fernández-García, M. Role of Interface Contact in CeO2-TiO2 Photocatalytic Composite Materials. ACS Catalysis 2014, 4 (1), 63–72. https://doi.org/10.1021/cs400878b.
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Gerward, L., i J. Staun Olsen. "Powder diffraction analysis of cerium dioxide at high pressure". Powder Diffraction 8, nr 2 (czerwiec 1993): 127–29. http://dx.doi.org/10.1017/s0885715600017966.
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CeO2 transforms to an orthorhombic PbCl2-type structure at a pressure of about 31 GPa. The phase transition is accompanied by a 9.8% volume contraction. The bulk modulus of the low-pressure fluorite-type structure is 236(4) GPa. Comparisons are made with the high-pressure behaviour of UO2 and ThO2.
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Li, Yan, Hongmei Sun, Zhiqi Yin, Xuexi Guo i Jun Yan. "Anti-Inflammatory Effects of Cerium Dioxide Nanoparticles on Peritonitis in Rats Induced by Staphylococcus epidermidis Infection". Advances in Polymer Technology 2020 (25.03.2020): 1–9. http://dx.doi.org/10.1155/2020/3591508.
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Objective. To investigate the effects of cerium dioxide (CeO2) nanoparticles on the inflammatory response of peritonitis rats induced by Staphylococcus epidermidis infection. Methods. Green tea polyphenol CeO2 nanoparticles were synthesized and characterized by transmission microscopy, ultraviolet-visible spectroscopy, FT-IR, and powder diffractometer. 40 male adult SD rats were randomly divided into 4 groups (n = 10 each): a control group, a model group, a CeO2 group, and a CeO2 + model group. Staphylococcus epidermidis solution was injected intraperitoneally with 107 CFU/ml of bacterial solution in the model group, while the control group was injected intraperitoneally with the same amount of normal saline, and the CeO2 and CeO2 + model groups were injected with 0.5 mg/kg CeO2 nanoparticles through the tail vein for 2 h and then injected with saline or bacterial solution for 2 h, respectively. After 0 h, 3 h, 12 h, 24 h, and 48 h of model construction, rats were sacrificed, and serum and peritoneal lavage fluid were collected. The total number of leukocytes and the percentage of each type of leukocytes in the peritoneal lavage fluid were determined. Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of inflammatory factor TNF-α in serum and peritoneal lavage fluid, and myeloperoxidase (MPO) activity in peritoneal tissue was also measured. In addition, real-time fluorescence quantitative PCR (RT-PCR) was used to measure the expression of TLR2 and TLR4 in peritoneal tissue, and western blotting was used to detect the expression of TLR2, TLR4, and the activation of NF-κB signaling pathways as well. Results. The CeO2 has an average size of 37 ± 3 nm with binding activity to proteins, phenolic compounds, and alkaloids. After counting the white blood cells in the peritoneal lavage fluid, it was found that the total number of white blood cells and the percentage of neutrophils in the model group were significantly increased (both P<0.05), and CeO2 treatment significantly reversed the above changes (both P<0.05). The ELISA results showed that compared with the control group, the TNF-α in the peritoneal lavage fluid and serum of the model group increased in a time-dependent manner (all P<0.05); however, there was no significant change in the CeO2 group (P>0.05); at the same time in the CeO2 + model group, the TNF-α content was significantly reduced (all P<0.05). Detection of MPO activity in peritoneal tissue revealed that MPO activity was significantly increased under peritonitis (all P<0.05), and CeO2 treatment could mitigate that increase (all P<0.05). RT-PCR results showed that compared with the control group, the expression of TLR2 and TLR4 mRNA levels in the peritoneum of the model group were increased in a time-dependent manner (all P<0.05), and there was no significant change in the CeO2 group (P>0.05); however, TLR2 and TLR4 mRNA levels were significantly reduced in the CeO2 + model group (all P<0.05). Western blotting test was performed on the peritoneal tissue collected after 48 h of the model establishment. Compared with the control group, the levels of TLR2, TLR4, p–NF–κB, and p-IκBα protein in the model group were significantly increased (all P<0.05), while CeO2 group showed no significant changes (P>0.05) and administration of CeO2 before model construction can significantly reverse the above protein activation (all P<0.05). Conclusion. CeO2 nanoparticles have anti-inflammatory effects in peritonitis caused by Staphylococcus epidermidis infection.
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Budiman, Harry, i Oman Zuas. "Adsorption Isotherm Studies on Acid Orange-10 Dye Removal using Cerium Dioxide Nanoparticles". Indonesian Journal of Chemistry 14, nr 3 (23.10.2014): 226–32. http://dx.doi.org/10.22146/ijc.21232.
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The adsorption capacity of AO-10 from aqueous solution onto CeO2-NPs was investigated under various reaction parameters. Batch mode experiments were conducted to assess the potential of the CeO2-NPs as adsorbent for the removal of AO-10 dye from aqueous solution. Equilibrium isotherm studies were carried out under an optimum reaction condition (i.e., AO-10 dye concentration = 15 mg/L, CeO2-NPS dosage = 2 g/L, pH of dye solution = 2) obtained from this study. The equilibrium data obtained were fitted to Langmuir, Freundlich, and Redlich-Peterson isotherm models. The results shows that, the linear transform model provided the highest regression coefficient (R2 = 0.991) with the Langmuir model. The maximum monolayer adsorption capacity was found to be 33.33 mg/g at 30 °C, which is higher than some data from published literature.
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Azhar, Mustaffa Ali, Monna Rozana, Mabel de Cunha, Dede Miftahul Anwar, Ehsan Ahmadi, Abdul Razak Khairunisak, Kuan Yew Cheong i Zainovia Lockman. "Effect of Annealing Temperature of Hybrid CeO2/TiO2 Nanotubes on the Photocurrent". Advanced Materials Research 1024 (sierpień 2014): 132–35. http://dx.doi.org/10.4028/www.scientific.net/amr.1024.132.
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Cerium oxide (CeO2) or known as ceria were deposited on titanium dioxide, TiO2, nanotubes by electrodeposition process as to produce hybrid materials that can generate photocurrent. The electrodeposition process is done by using 0.1 M cerium chloride mixed with 0.1 M ammonium acetate as ligands to promote stability complexes in a standard two electrode bath. Voltage and pH were controlled to ensure the most optimum condition of cerium oxide deposition. Samples were then annealed at different temperatures. Photocurrent results indicate that annealed sample at 450°C shows the best photocurrent due to high degree of anatase and cubic crystallinity.
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Baikin, A. S., E. O. Nasakina, A. G. Kolmakov, K. V. Sergienko, M. A. Sudarchikova i M. A. Sevostyanov. "Properties of coatings based on cerium dioxide produced by magnetron sputtering". Physics and Chemistry of Materials Treatment 1 (2023): 64–75. http://dx.doi.org/10.30791/0015-3214-2023-1-64-74.
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The unique set of properties of coatings based on CeO2 has long been used in many industries. But the range of their potential application is no less wide, especially in view of the discovery of new properties. Magnetron deposition technology expands the area of possible application of coatings based on CeO2, making it possible to obtain products of various sizes and geometries. This review presents the parameters of magnetron sputtering of coatings based on cerium dioxide, their relationship with the structure and key properties of these coatings. The influence of the type of target, the introduction of oxygen into the sputtering medium, changes in the sputtering power, bias voltage, type of substrate and its temperature on the structure, mechanical properties, and hydrophobicity are considered.
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Pan, M. "Observation of in situ reduction of ceria-supported rhodium catalysts by electron beam irradiation". Proceedings, annual meeting, Electron Microscopy Society of America 49 (sierpień 1991): 1022–23. http://dx.doi.org/10.1017/s0424820100089421.
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In rhodium catalysts supported on lanthanide oxides, significant difference in rhodium dispersions has been observed between cerium dioxide (CeO2) and sesquioxides (Ln2O3) by high resolution electron microscopy (HREM). This has been attributed to the different behaviors of the oxide supports during their impregnation with aqueous solution of rhodium nitrate (Rh(NO3)3). In the acid media, cerium dioxide has a higher reducibility while the sesquioxides have a higher solubility. So studying the catalyst precursor and the reduction process can provide an understanding of its interaction with the support during the impregnation stage and the metal dispersion on the oxide supports. Results on cerium dioxide support are presented here.The catalyst precursor was prepared by incipient wetness impregnation method as reported elsewhere. The rhodium loading was 2.4 wt%. The HREM work was performed in JEOL 4000EX electron microscope (point resolution of 1.7 Å). The typical current density used during observation was ∼6.5A/cm2 at the specimen. The vacuum in the column of the microscope was ∼10-7 torr.
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Kozlova, Taisiya O., Darya N. Vasilyeva, Daniil A. Kozlov, Irina V. Kolesnik, Maria A. Teplonogova, Ilya V. Tronev, Ekaterina D. Sheichenko i in. "A Comparative Study of Cerium(III) and Cerium(IV) Phosphates for Sunscreens". Molecules 29, nr 9 (6.05.2024): 2157. http://dx.doi.org/10.3390/molecules29092157.
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Crystalline cerium(III) phosphate (CePO4), cerium(IV) phosphates, and nanocrystalline ceria are considered to be promising components of sunscreen cosmetics. This paper reports on a study in which, for the first time, a quantitative comparative analysis was performed of the UV-shielding properties of CePO4, Ce(PO4)(HPO4)0.5(H2O)0.5, and CePO4/CeO2 composites. Both the sun protection factor and protection factor against UV-A radiation of the materials were determined. Ce(PO4)(HPO4)0.5(H2O)0.5 was shown to have a sun protection factor of 2.9, which is comparable with that of nanocrystalline ceria and three times higher than the sun protection factor of CePO4. Composites containing both cerium dioxide and CePO4 demonstrated higher sun protection factors (up to 1.8) than individual CePO4. When compared with the TiO2 Aeroxide P25 reference sample, cerium(III) and cerium(IV) phosphates demonstrated negligible photocatalytic activity. A cytotoxicity analysis performed using two mammalian cell lines, hMSc and NCTC L929, showed that CePO4, Ce(PO4)(HPO4)0.5(H2O)0.5, and nanocrystalline ceria were all non-toxic. The results of this comparative study indicate that cerium(IV) phosphate Ce(PO4)(HPO4)0.5(H2O)0.5 is more advantageous for use in sunscreens than either cerium(III) phosphate or CePO4/CeO2 composites, due to its improved UV-shielding properties and low photocatalytic activity.
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Channei, D., A. Nakaruk, S. Phanichphant, P. Koshy i C. C. Sorrell. "Cerium Dioxide Thin Films Using Spin Coating". Journal of Chemistry 2013 (2013): 1–4. http://dx.doi.org/10.1155/2013/579284.
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Cerium dioxide (CeO2) thin films with varying Ce concentrations (0.1 to 0.9 M, metal basis) were deposited on soda-lime-silica glass substrates using spin coating. It was found that all films exhibited the cubic fluorite structure after annealing at 500°C for 5 h. The laser Raman microspectroscopy and GAXRD analyses revealed that increasing concentrations of Ce resulted in an increase in the degree of crystallinity. FIB and FESEM images confirmed the laser Raman and GAXRD analyses results owing to the predicted increase in film thickness with increasing Ce concentration. However, porosity and shrinkage (drying) cracking of the films also increased significantly with increasing Ce concentrations. UV-VIS spectrophotometry data showed that the transmission of the films decreased with increasing Ce concentrations due to the increasing crack formation. Furthermore, a red shift was observed with increasing Ce concentrations, which resulted in a decrease in the optical indirect band gap.
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Habib, Sehrish, Eman Fayyad, Muddasir Nawaz, Adnan Khan, Rana A. Shakoor, Ramazan Kahraman i Aboubakr Abdullah. "Cerium Dioxide Nanoparticles as Smart Carriers for Self-Healing Coatings". Nanomaterials 10, nr 4 (20.04.2020): 791. http://dx.doi.org/10.3390/nano10040791.
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The utilization of self-healing cerium dioxide nanoparticles (CeO2), modified with organic corrosion inhibitors (dodecylamine (DDA) and n-methylthiourea (NMTU)), in epoxy coating is an efficient strategy for enhancing the protection of the epoxy coating and increasing its lifetime. Fourier transform infrared (FTIR) spectroscopy analysis was used to confirm the loading and presence of inhibitors in the nanoparticles. Thermal gravimetric analysis (TGA) measurement studies revealed the amount of 25% and 29.75% w/w for NMTU and DDA in the nanoparticles, respectively. The pH sensitive and self-release behavior of modified CeO2 nanoparticles is confirmed through UV-vis spectroscopy and Zeta potential. It was observed, through scanning electron microscopy (SEM), that a protective layer had been formed on the defect site separating the steel surface from the external environment and healed the artificially created scratch. This protective film played a vital role in the corrosion inhibition of steel by preventing the aggressiveness of Cl− in the solution. Electrochemical impedance spectroscopy (EIS) measurements exhibited the exceptional corrosion inhibition efficiency, reaching 99.8% and 95.7% for the modified coating with DDA and NMTU, respectively, after five days of immersion time.
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VORONIN , MIKHAIL, NATALIA GAVRILOVA , ELEONORA KOLTSOVA i ANDREY ZHENSA. "SIMULATION OF AGGREGATION PROCESS IN CERIUM AND ZIRCONIUM DIOXIDE NANOPARTICLES". Computational Nanotechnology 9, nr 3 (28.09.2022): 73–79. http://dx.doi.org/10.33693/2313-223x-2022-9-3-73-79.
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A study of the aggregative stability of the CeO2-ZrO2 system was carried out in various pH ranges of the medium. To create a mathematical model of the stability of aggregates, the generalized DLVO theory was taken. The parameters of the structural component of the potential energy of particle interaction are determined using the principle of minimum entropy production. The limiting particle sizes of an an aggregatively stable system are determined.
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Obradovych, Anastasiia, Liliia Vasina i Nadiia Zholobak. "Effect of cerium dioxide nanoparticles on certain indication of synthetic activity Rhodotorula glutinis". Biolohichni systemy 12, nr 2 (23.12.2020): 166–73. http://dx.doi.org/10.31861/biosystems2020.02.166.
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Cerium dioxide nanoparticles (CeO2 NP) have significant catalytic and antioxidant properties due to their ability to inhibit the development of free-radical reactions due to a combination of superoxidedismutase and catalase mimetic activities. This nanopreparation has a significant antibacterial effect, but is low-toxic to unicellular yeast Saccharomyces cerevisiae. Therefore, it is relevant and appropriate to study the effect of this compound on other groups of yeast, in particular members of the genus Rhodotorula spp., which are characterized by high growth rate, unpretentiousness to the component composition of the culture medium, the ability to form a variety of valuable biologically active compounds, as well as the ability to synthesize proteins, lipids, carotenoids and exopolysaccharides in the complex. The report that microorganisms of this genus have been identified as part of the normal fish microbiota (Abramis brama, Rutilus rutilus, Perca fluviatilis, Oreochromis niloticus) expands the range of their use, either as probiotics in general or their individual cellular and extracellular components as prebiotics. In this work, the effect of different concentrations of CeO2 NP nanopreparation on the production parameters of Rhodotorula glutinis was studied, as well as their antagonistic properties after saturation of nanocerium were tested. To detect the optimal concentration of nanopreparation of cerium dioxide, R. glutinis was cultured for 120 h at 28 0C and aerated at 160 rpm on Saburo medium with the addition of citrate-stabilized CeO2 NP with a particle size of 1-2 nm in the following concentrations: 100 mM, 10 mM, 1 mM, 0,1 mM, 0,01 mM. The control was R. glutinis grown on Saburo medium, experimental controls were represented by microorganisms in the culture medium of which citrate and full-size cerium (CeCl3) were added. It was found that most of the studied concentrations of CeO2 NP (except for the highest) are not toxic to these carotenogenic yeasts. The presence of 10 mM CeO2 NP stimulates the growth of the culture, while the increase in biomass is increased by fourfold compared to the control. There was also an increase in the content of basic metabolites – protein by 1,2 times, lipids by 2,5 times and valuable biologically active compounds - carotenoids by 20% and exopolysaccharides by 2,2 times. However, under these conditions, no significant changes in catalase and superoxidase activities were registered. Examination of the antagonistic properties of the CeO2 NP-enriched culture of R. glutinis by delayed antagonism by the method of perpendicular strokes against gram-positive B. subtilis and gram-negative P. syringae bacteria showed the presence of lysis zones up to 17 and 25 mm, respectively, in contrast to their complete or complete absence (2 mm), noted in the study of control samples. A study of the resistance of CeO2 NP-enriched culture of R. glutinis to natural inhibitors of the digestive tract showed resistance of microorganisms to gastric juice (the amount of CFU is 1,4 times higher than control values) and bile (recorded a 5-fold increase in survival of microorganisms). The obtained results testify to the prospects of using nanocerium for mobilization of growth, enzymatic, antagonistic activities of R. glutinis culture.
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Manan, Wan Nabilah, Wan Nor Roslam Wan Isahak i Zahira Yaakob. "CeO2-Based Heterogeneous Catalysts in Dry Reforming Methane and Steam Reforming Methane: A Short Review". Catalysts 12, nr 5 (19.04.2022): 452. http://dx.doi.org/10.3390/catal12050452.
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Transitioning to lower carbon energy and environment sustainability requires a reduction in greenhouse gases such as carbon dioxide (CO2) and methane (CH4) that contribute to global warming. One of the most actively studied rare earth metal catalysts is cerium oxide (CeO2) which produces remarkable improvements in catalysts in dry reforming methane. This paper reviews the management of CO2 emissions and the recent advent and trends in bimetallic catalyst development utilizing CeO2 in dry reforming methane (DRM) and steam reforming methane (SRM) from 2015 to 2021 as a way to reduce greenhouse gas emissions. This paper focus on the identification of key trends in catalyst preparation using CeO2 and the effectiveness of the catalysts formulated.
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Yan, Junzhi, Yuming Sun, Junxi Cai, Ming Cai, Bo Hu, Yan Yan, Yue Zhang i Xu Tang. "Construction of ZnCdS Quantum-Dot-Modified CeO2 (0D–2D) Heterojunction for Enhancing Photocatalytic CO2 Reduction and Mechanism Insight". Catalysts 14, nr 9 (6.09.2024): 599. http://dx.doi.org/10.3390/catal14090599.
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It is important to improve the separation ability of photogenerated electrons and the adsorption capacity of carbon dioxide (CO2) for efficient photoreduction of CO2. Here, we synthesized ZnCdS quantum dots (ZCS-QDs) and cerium dioxide nanosheets (CeO2) using the solvothermal method and calcination method. We combined CeO2 and ZCS-QDs to effectively enhance the charge separation efficiency, and the lifetime of photogenerated electrons was increased 4.5 times. The CO evolution rate of the optimized composite (ZCS-QDs/CeO2) was up to 495.8 μmol g−1 h−1, and it had 100% product selectivity. In addition, the stability remained high after five cycles. The CO2 adsorption capacity of the catalyst surface was observed by in situ FTIR. The test results showed that improving CO2 capture ability and promoting photogenic electron separation had positive effects on enhancing photoreduction of CO2. This study provides a reference for constructing a zero-dimensional–two-dimensional (0D–2D) heterojunction and explores potential CO2 reduction reaction mechanisms.
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Deval, Gaëlle, Margaux Nedder, Séverine Degrelle, Jasmina Rogozarski, Marie-Léone Vignaud, Audrey Chissey, Stacy Colzin i in. "Benzo(a)pyrene and Cerium Dioxide Nanoparticles in Co-Exposure Impair Human Trophoblast Cell Stress Signaling". International Journal of Molecular Sciences 24, nr 6 (12.03.2023): 5439. http://dx.doi.org/10.3390/ijms24065439.
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Human placenta is a multifunctional interface between maternal and fetal blood. Studying the impact of pollutants on this organ is crucial because many xenobiotics in maternal blood can accumulate in placental cells or pass into the fetal circulation. Benzo(a)pyrene (BaP) and cerium dioxide nanoparticles (CeO2 NP), which share the same emission sources, are found in ambient air pollution and also in maternal blood. The aim of the study was to depict the main signaling pathways modulated after exposure to BaP or CeO2 NP vs. co-exposure on both chorionic villi explants and villous cytotrophoblasts isolated from human term placenta. At nontoxic doses of pollutants, BaP is bioactivated by AhR xenobiotic metabolizing enzymes, leading to DNA damage with an increase in γ-H2AX, the stabilization of stress transcription factor p53, and the induction of its target p21. These effects are reproduced in co-exposure with CeO2 NP, except for the increase in γ-H2AX, which suggests a modulation of the genotoxic effect of BaP by CeO2 NP. Moreover, CeO2 NP in individual and co-exposure lead to a decrease in Prx-SO3, suggesting an antioxidant effect. This study is the first to identify the signaling pathways modulated after co-exposure to these two pollutants, which are common in the environment.
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Miccio, Francesco, Mauro Mazzocchi, Mattia Boscherini, Alba Storione, Matteo Minelli i Ferruccio Doghieri. "The Trade-Off between Combustion and Partial Oxidation during Chemical Looping Conversion of Methane". Energies 17, nr 11 (5.06.2024): 2764. http://dx.doi.org/10.3390/en17112764.
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The chemical looping reforming and combustion of methane have attracted increasing interest as processes for clean energy and syngas production, with potential to reduce carbon dioxide emissions. Previous literature on the development of oxygen carriers evidenced the effects that oxygen availability exerts on the selectivity of the oxidation reaction. In the present paper, we evaluate the performance of chromite sand (Chro), cerium dioxide (CeO2), and mixed cerium–copper oxide (Ce–Cu) as oxygen carriers for either reforming or combustion according to their oxygen availability. The oxides are tested in 2 to 5 min reduction intervals in a CH4/N2 mixture (5, 10 and 20% vol.) followed by regeneration in O2/N2 (3, 5, or 21% vol.), with redox cycles conducted either at 850 °C or 950 °C. The obtained rank of selectivity towards complete CH4 combustion is Ce–Cu > CeO2 > Chro. Another relevant finding is the role of the degree of carrier conversion in promoting partial or total oxidation. In particular, the selectivity towards CO2 markedly decreases at increasing carrier conversion, disclosing new strategies for process design and optimization by controlling the carrier conversion degree.
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Gevorkyan, Edwin Spartakovych, Volodymyr Pavlovych Nerubatskyi, Oksana Mykolaivna Morozova, Dmytro Semenovych Sofronov, Volodymyr Oleksiyovych Chyshkala i Liudmyla Volodymyrivna Voloshyna. "DEVELOPMENT of CERAMIC MATERIALS ZrO2–CeO2 of BIOENGINEERING APPLICATIONS". Collected scientific works of Ukrainian State University of Railway Transport, nr 199 (10.06.2022): 6–16. http://dx.doi.org/10.18664/1994-7852.199.2022.258543.
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Method of composite materials formation based on particle-stabilized cerium dioxidezirconium nanopowders obtained from fluoride salt solutions has been investigated. The sintering ofthe powders was carried out by means of an electroconsolidation apparatus by hot pressing in avacuum chamber. X-ray phase analysis was performed on a Shimadzu XRD-6000 diffractometer.Phase analysis of the samples was carried out using the data base of the American Society for TestingMaterials. The surface morphology of the samples was investigated by scanning microscope JSM-6390LV. The most optimal method of nanopowders extraction was selected to produce solidnanostructured composites for bioengineering applications. Analysis of the microstructure of thesamples showed that the composite systems are composed of particles ranging in size from 100 nmto 1500 nm. The samples show pores and cracks, which can be associated with the passage of grainboundary diffusion in the process of electro-consolidation of the samples. Derivation of compositesbased on zirconium dioxide stabile at hot vacuum deposition by electrosintering makes it possible to obtain the high performance composites with high resistance to abrasion, hardness and thrustmodulus at a temperature of 1400 °C, a pressure of 30 MPa and a cycle time of 3 minutes. It wasfound that the method of electroconsolidation in vacuum provides the bonding of samples with highvalues of the Young’s modulus and friction strength. Mechanical characteristics of ceramic systemsbased on zirconium dioxide, molded with cerium oxide, have rather high values. The dependence ofchange in the relative specific gravity of the studied samples shows that the increase in temperatureof electroconsolidation, the overall level of composite density grows practically linearly, indicatinga good particle compatibility of the powders. The conducted studies allow us to assume that with thepurpose of further increasing of the properties of composites based on zirconium oxide, partiallystabilized by cerium dioxide, it is necessary to improve the homogeneity of the resulting sums andadd other oxides, in particular alumina oxide, alumina nitride, silicon oxide and magnesium oxide.
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Gamucci, Olimpia, i Giuseppe Bardi. "Cerium dioxide nanoparticles selectively up-regulate C-C chemokine receptor 2 and CD16 expression on human monocytes". EURO-NanoTox-Letters 5, nr 1 (1.12.2014): 1–16. http://dx.doi.org/10.1515/entl-2015-0005.
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Abstract Cerium dioxide nanoparticles (CeO2 NPs) are known as scavengers of reactive oxygen species for the coexistence of Ce3+/ Ce4+ oxidation states. Cell treatments with CeO2 NPs often lead to controversial pro-inflammatory and anti-inflammatory results. The aim of the study was to investigate the immune events following the administration of ceria nanoparticles to THP-1 monocytes. To address this issue, we performed flow cytometry, chemotaxis and ELISA experiments on THP-1 monocytes treated with different concentrations of CeO2 NPs. CeO2 nanoparticle treatments induced a significant pro-inflammatory C-C chemokine receptor 2 (CCR2) up-regulation within the first 6 hours lasting over-expressed for 24 hours. Differently, CCR5 showed no response at any concentration tested. Enhanced chemotaxis towards the CCR2 specific ligand MCP-1 reinforced the observation demonstrating a functional immune outcome. The pro-inflammatory profile of the treated monocytes was also supported by CD16 up-regulation but no differences in CX3CR1 or other monocyte receptors, like CD11b and CD14, were detectable. Moreover, CeO2 NPs exposure did not promote any release of inflammatory cytokines suggesting a specific and direct effect of the nanoparticles on CCR2 and CD16. Our in vitro results reveal a specific role of CeO2 NPs in the up-regulation of CCR2, which might contribute to increase the pro-inflammatory monocyte/macrophage migration toward the sites of CCL2 expression.
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Nedder, Margaux, Sonja Boland, Stéphanie Devineau, Amal Zerrad-Saadi, Jasmina Rogozarski, René Lai-Kuen, Ibtissem Baya i in. "Uptake of Cerium Dioxide Nanoparticles and Impact on Viability, Differentiation and Functions of Primary Trophoblast Cells from Human Placenta". Nanomaterials 10, nr 7 (3.07.2020): 1309. http://dx.doi.org/10.3390/nano10071309.
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The human placenta is at the interface between maternal and fetal circulations, and is crucial for fetal development. The nanoparticles of cerium dioxide (CeO2 NPs) from air pollution are an unevaluated risk during pregnancy. Assessing the consequences of placenta exposure to CeO2 NPs could contribute to a better understanding of NPs’ effect on the development and functions of the placenta and pregnancy outcome. We used primary villous cytotrophoblasts purified from term human placenta, with a wide range of CeO2 NPs concentrations (0.1–101 μg/cm2) and exposure time (24–72 h), to assess trophoblast uptake, toxicity and impact on trophoblast differentiation and endocrine function. We have shown the capacity of both cytotrophoblasts and syncytiotrophoblasts to internalize CeO2 NPs. CeO2 NPs affected trophoblast metabolic activity in a dose and time dependency, induced caspase activation and a LDH release in the absence of oxidative stress. CeO2 NPs decreased the fusion capacity of cytotrophoblasts to form a syncytiotrophoblast and disturbed secretion of the pregnancy hormones hCG, hPL, PlGF, P4 and E2, in accordance with NPs concentration. This is the first study on the impact of CeO2 NPs using human primary trophoblasts that decrypts their toxicity and impact on placental formation and functions.
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Rukiye, Öztekin, i Sponza Delia Teresa. "Photocatalytic Degradation of Polyphenols and Polyaromatic Amines in Textile Industry Wastewaters by Nano-Cerium Dioxide Doped Titanium Dioxide and the Evaluation of Acute Toxicity Assays with Microtox and Daphnia magna". Journal of Biomedical Research & Environmental Sciences 3, nr 8 (2022): 852–66. http://dx.doi.org/10.37871/jbres1524.
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In this study, nano-cerium dioxide doped titanium-dioxide (CeO2 -TiO2 ) Nanocomposites (NCs) was used for the photocatalytic degradation of pollutant parameters (color, polyphenols, polyaromatics) from a textile industry wastewater (TI ww) treatment plant located in Izmir, Turkey, at different operational conditions such as at increasing photocatalytic time (0, 10, 15, 20, 30, 60, 90 and 120 min), at different CeO2 -TiO2 mass ratios (1%, 3%, 5%, 10%, 15%, 16%, 25%, 30%, 50%), at the different amounts of CeO2 (1, 3, 5, 8, 10, 15, 20 and 25 mg/L) under 130 W Ultraviolet (UV) and 35 W sun lights irradiations, respectively. Color, polyphenols (quercetin, fi setin, ellargic acid, carminic acid, luteolin, and curcumin) and polyaromatics [2,6-dimethylaniline (2,6-DMA), 2-aminoanisole (MOA), 2,4-toluenediamine (TDA), 2-naphthylamine (NA), 4,40-thiobisbenzenamine (TOA), 3,3-dichlorobenzidine (DCB) and 3,30-dimethoxybenzidine (DMOB)] removal effi ciencies were observed between 78% and 99% during photocatalytic experiments, under ¬130 W UV light, at 15% CeO2 -TiO2 NCs, at 21° C, after 30 min irradiation time. 15% CeO2 -TiO2 NCs shows the highest photodegradation yield of color under both UV and visible-light irradiation, with maximum photodegradation rates of 99% and 98.5%, respectively, after 30 min irradiation time. 94.44% maximum Microtox acute toxicity yield was found in CeO2 -TiO2 NCs = 20 mg/L, at 5% CeO2 mass ratio, after 150 min photodegradation time at 60o C. 90% maximum Daphnia magna acute toxicity removal was obtained in CeO2 -TiO2 NCs = 20 mg/L, at 5% CeO2 mass ratio, after 150 min photodegradation time at 60° C. The results show that the CeO2 -TiO2 NCs has a high photocatalytic activity to remove the pollutants from TI ww.