ceric oxide (Total 242091 Papers Found)

The formation of nanorods, driven by the physicochemical phenomena during the freezing and after the aging of frozen ceria nanoparticle suspensions, is reported. During freezing of a dilute aqueous solution of CeO2 nanocrystals, some nuclei remain in solution while others are trapped inside micro- and nanometer voids formed within the growing ice front. Over time (2-3 weeks) the particles trapped within the nanometer-wide voids in the ice combine by an oriented attachment process to form ceria n ...
We have studied (001) surface terminated cerium oxide nanoparticles grown on a ruthenium substrate using physical vapor deposition. Their morphology, shape, crystal structure, and chemical state are determined by low-energy electron microscopy and micro-diffraction, scanning probe microscopy, and synchrotron-based X-ray absorption spectroscopy. Square islands are identified as CeO2 nanocrystals exhibiting a (001) oriented top facet of varying size; they have a height of about 7 to 10 nm and a si ...
adolinium-doped ceria has demonstrated a high-ionic conductivity at moderate temperatures and is a potential candidate as electrolyte in solid xide fuel cell (SOFC) devices. However, Ce ions can undergo a valency change from +IV to +III under reducing conditions. That valency change hen leads to electronic (polaron) conduction and thus, degrades the ionic conduction. It has been demonstrated that the incorporation of electrically nsulating particles will reduce the electronic conduction by an ...
BACKGROUND Cerium oxide nanoparticles have gained much more attention especially in the field of nanomedicine. This work represents cerium oxide nanoparticles as a new prophylactic model for heart failure progression. OBJECTIVE To investigate the potential protective effect of cerium oxide nanoparticles on Isoproterenol (ISO)-induced cardiac toxicity in rats. METHODS Cerium oxide nanoparticles (5±1nm) were synthesized by reverse micelle method and characterized using High Resolution Transmi ...
Background Cerium oxide (CeO2) is a technologically important material due to its properties and applications in several areas that range from engineering to biological sciences. Despite the hydrothermal microwave method versatility, its crystallization kinetics has low speed when the processing temperatures are below 300°C which are the desired conditions for soft chemistry processes [1,2]. At lower temperatures it was found that this material has antimicrobial activity against several bacteri ...
In this study, an enzymatic biosensor for amperometric detection of hydrogen peroxide was developed based on the direct electrochemistry of myoglobin (Mb) on a porous cerium dioxide (CeO2) nanostructured film. The developed film accomplished with large surface area was electrodeposited on an indium tin oxide (ITO) substrate. Surface morphological studies revealed that the formed CeO2 film has a large specific surface area with a unique nanostructure on the ITO surface. Cyclic voltammetry (CV) an ...
Surface adsorption of a homologous series of pyridine carboxylic acids on a hydrated colloidal cerium dioxide (ceria) film is characterized using the combination of experimental and computationally determined infrared (IR) spectra. Experimental analyses employ attenuated total reflectance (ATR) IR spectroscopy of deposited colloidal ceria thin films equilibrated with three pyridine carboxylic acids at pH 3.0, 5.5, and 8.5. The corresponding computational IR spectra for the energy-minimized inter ...
Innovative materials and application techniques are constantly being developed in the ongoing search for improved restorations. This article describes a new material and the fabrication process of aesthetic machinable ceramic anterior implant abutments. The ceramic material utilized is a mixture of alumina (aluminum oxide) and ceria (cerium oxide) with partially stabilized zirconia (zirconium oxide). The initial core material is a cylinder with a 9-mm diameter and a 15-mm height, obtained by cer ...
Currently, nanoparticles are synthesized and used at an unprecedented rate for industrial, medical, and research applications. The use of cerium oxide nanoparticles (CeONP) and yttrium oxide nanoparticles (YtONP) results in their spread as contaminants into the environment. Once in the environment, CeONP and YtONP can be taken up by organisms in the food chain where they may pose a public health risk. In this study we determine whether Acanthamoeba castellanii and Daphnia magna uptake CeONP or Y ...
A combined process of coagulation-catalytic ozonation-anaerobic sequencing batch reactor (ASBR)-SBR was developed at lab scale for treating a real sodium dithionite wastewater with an initial chemical oxygen demand (COD) of 21,760-22,450 mg/L. Catalytic ozonation with the prepared cerium oxide (CeO2)/granular activated carbon catalyst significantly enhances wastewater biodegradability and reduces wastewater microtoxicity. The results show that, under the optimum conditions, the removal efficie ...
Cerium oxide nanoparticles (CNPs) contain several properties such as catalytic activity, fluorescent quencher and electrochemical, high surface area, and oxygen transfer ability, which have attracted considerable attention in developing high-sensitive biosensors. CNPs can be used as a whole sensor or a part of recognition or transducer element. However, reports have shown that applying these nanoparticles in sensor design could remarkably enhance detection sensitivity. CNP's outstanding properti ...
The aim of the study was to investigate the interaction and the short-term effects of increasing doses of cerium dioxide nanoparticles (CeO2 NPs) on ram spermatozoa, stored at 4 °C for up to 24 hours, on the main functional and kinematic parameters. Spermatozoa were incubated with 0, 22, 44, and 220 μg/mL of CeO2 NPs at 4 °C and submitted at 0, 2, and 24 hours to the following analyses: (1) intracellular uptake of CeO2 NPs by the spermatozoa; (2) kinematic parameters; (3) acrosome and memb ...
The metal oxide affinity chromatography (MOAC) materials have been extensively used for extraction of phosphate compounds in the past decade. Actually, some of these materials also possess adsorption affinity towards cis-diol-containing compounds, which was seldom explored in separation field so far. Here we present the proof-of-concept study to evaluate the feasibility of expanding MOAC for specific capture of cis-diol biomolecules. Benefitting from the high commercialisation of the metal oxide ...
The efficacy of using cerium oxide foams as a support for Au nanoparticles and subsequent use as oxidation catalysts have been investigated. These were synthesized using L-asparagine to produce a cerium coordination polymer foam, which was calcined to give the oxide foam. Au nanoparticles were supported on the CeO(2) foams using a sol-immobilization method. The activity of the Au/foamCeO(2) for solvent-free benzyl alcohol oxidation was superior to standard Au/CeO(2) catalysts, and the activity w ...
Ultrathin CeO2 nanowires with a diameter of 5 nm and an aspect ratio of more than 100 can be prepared by a one-step refluxing approach in a mixed solvent composed of water and ethanol without using any templates or surfactants. The formation mechanism of the as-synthesized ultrathin nanowires has been investigated. The as-synthesized CeO2 nanowires with a high surface area of 125.31 m2 g-1 exhibited excellent wastewater treatment performance with high removal capacities towards organic dyes and ...
Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure fo ...
Studies have shown that CeO₂ nanoparticles (NPs) can be accumulated in plants without modification, which could pose a threat for human health. In this research, cilantro (Coriandrum sativum L.) plants were germinated and grown for 30 days in soil amended with 0 to 500 mg kg⁻¹ CeO₂ NPs and analyzed by spectroscopic techniques and biochemical assays. At 125 mg kg⁻¹, plants produced longer roots (p ≤ 0.05), and at 500 mg kg⁻¹, there was higher Ce accumulation in tissues (p ≤ 0.05) ...
Previous studies in steel cleanness have been hampered by limited control of inclusions’ phase and composition. This limited control is often a result of studying inclusion formation and development using industrial steel melts and the inclusions therein as starting material. This is an extremely complex situation and not always readily amenable to analysis. A new experimental laboratory technique has been developed that allows addition of inclusions of known, size, phase and composition to be ...
The use of manufactured cerium oxide nanoparticles (CeO2-NPs) in consumer products has increased markedly over the past decade, and their release into natural ecosystems is unavoidable. This study investigated the phytotoxicity and uptake of CeO2-NPs in Arabidopsis thaliana grown in an agar medium. Although low concentrations of CeO2-NPs had stimulatory effects on plant growth, at higher concentrations, CeO2-NPs reduced growth and had adverse effects on the antioxidant systems and photosystem. I ...
Ceria nanoparticles (NPs) are fundamental in heterogeneous catalysis because of their ability to store or release oxygen depending on the ambient conditions. Their oxygen storage capacity is strictly related to the exposed planes, crystallinity, density and distribution of defects. In this work a study of ceria NPs produced with a ligand-free, physical synthesis method is presented. The NP films were grown by a magnetron sputtering based gas aggregation source and studied by high resolution- and ...
Supercritical fluids offer fast and facile routes toward well-crystallized tailor-made cerium oxide nanoparticles. However, the use of surfactants to control morphology and surface properties remains essential. Therefore, although water, near-critical (nc) or supercritical (sc), is a solvent of choice, the poor water solubility of some surfactants could require other solvent systems such as alcohols, which could themselves behave as surface modifiers. In here, the influence of seven different al ...
In this work, superhydrophobic cerium oxide coating surface (111) with dual scale texture on Ni20Cr substrate is obtained by combination of electropolishing the substrate and subsequent cathodic electrodeposition and long-term UVH surface relaxation. To form hierarchical structures of CeO2 is controllable by varying the substrate roughness, and electropolishing period. The results indicated that at the optimal condition, the surface of the cerium oxide coating showed a superhydrophobicity with a ...
Increasingly, it is recognized that understanding and predicting nanoparticle behavior is often limited by the degree to which the particles can be reliably produced and adequately characterized. Two examples that demonstrate how sample preparation methods and processing history may significantly impact particle behavior are: 1) an examination of cerium oxide (ceria) particles reported in the literature in relation to the biological responses observed and 2) observations related that influence s ...
Due to the unique physical and chemical properties, nanosized cerium oxide (n-CeO2) has attracted considerable interest in many fields of research. The potential, the growing use and the mass production of n-CeO2 have stimulated research on their potential impact on the environment and human health. However, the toxicological definition for CeO2 nanoparticles (NPs) is still quite controversial. In the present work, we evaluated the antibacterial activity of CeO2 NPs sized ca. 7 nm (7-CeO2), ca. ...
Organophosphorus compounds (OP), which mainly penetrate via the percutaneous pathway, represent a threat for both military and civilians. Body surface decontamination is vital to prevent victims poisoning. The development of a cost-effective formulation, which could be efficient and easy to handle in case of mass contamination, is therefore crucial. Metal oxides nanoparticles, due their large surface areas and the large amount of highly reactive sites, present high reactivity towards OP. First, ...
To better understand the antioxidant (enzyme mimetic, free radical scavenger) versus oxidant and cytotoxic properties of the industrially used cerium oxide nanoparticles (nano-CeO(2)), we investigated their effects on reactive oxygen species formation and changes in the antioxidant pool of human dermal and murine 3T3 fibroblasts at doses relevant to chronic inhalation or contact with skin. Electron paramagnetic resonance (EPR) spin trapping with the nitrone DEPMPO showed that pretreatment of the ...
Male infertility has largely idiopathic, multifactorial origin. Oxidative stress is a major factor that affects spermatogenesis, in particular in aging. Cerium dioxide nanoparticles (CNPs) due to their antioxidative properties are promising to impact on the development of male infertility. The aims of this study were to investigate the effects of CNPs on fertility parameters in 24-month male rats and to overview relevant literature in the field of personalized treatments, predictive diagnosis, a ...
In the present study, cerium oxide (CeO2) nanoparticles were incorporated into poly (ε-caprolactone)/gelatin films in order to develop a potential wound dressing material. The wound dressings were prepared by electrospinning of poly (ε-caprolactone)/gelatin (1:1 (w/w)) solutions containing 1.50%, 3% and 6% (w/w) CeO2 nanoparticles. The electrospun films were evaluated regarding their morphology, contact angle, water-uptake capacity, water vapor transmission rate, tensile strength and cellular ...
The interaction between dopamine and the redox active cerium oxide nanoparticles, or nanoceria was studied using a suite of spectroscopic and surface characterization methods. Changes in the chemical reactivity and concentration of dopamine upon exposure to nanoceria was assessed in aqueous solutions and a human physiological fluid--human serum. The results indicate strong attachment of dopamine to the nanoparticle surface through oxidation followed by chemisorption of the oxidative product with ...
Engineered nanoparticles are widely incorporated into a large number of consumer products due to their specific physico-chemical properties in comparison to bulk materials. Cerium dioxide nanoparticles (CeO2) are currently used in several applications: as a component of catalytic converters, as a UV blocking or polishing agent or as a diesel fuel additive. The fate of engineered nanoparticles in the aquatic environment is highly dependent on their aggregation, transport and surface chemistry. In ...
We exploit a precipitation-redispersion mechanism for complexation of short chain polyelectrolytes with cerium oxide nanoparticles to extend their stability ranges. As synthesized, cerium oxide sols at pH 1.4 consist of monodisperse cationic nanocrystalline particles having a hydrodynamic diameter of 10 nm and a molecular weight of 400 000 g mol(-1). We show that short chain uncharged poly(acrylic acid) at low pH when added to a cerium oxide sols leads to macroscopic precipitation. As the pH is ...
Due to their catalytic and oxidative properties, cerium dioxide nanoparticles (CeO2NPs) are widely used as diesel additive or as promising therapy in cancerology; yet, scarce data are available on their toxicity, and none on their reproductive toxicity. We showed a significant decrease of fertilization rate, assessed on 1272 oocytes, during in vitro fertilization (IVF) carried out in culture medium containing CeO2NP at very low concentration (0.01 mg.l(-1)). We also showed significant DNA dama ...
Type I diabetes mellitus is a metabolic disease caused by the impairment of pancreatic β-cells mainly mediated through oxidative stress and related apoptosis. Islets transplantation seems a promising treatment for these patients, but during islets transplant, various types of stresses related to the isolation and transplantation procedure compromise the function and viability of islets. We recently hypothesized that the combination of cerium oxide (CeO2) and yttrium oxide (Y2O3) nanoparticles w ...
Nowadays, aerosol processes are widely used for the manufacture of nanoparticles (NPs), creating an increased occupational exposure risk of workers, laboratory personnel and scientists to airborne particles. There is evidence that possible adverse effects are linked with the accumulation of NPs in target cells, pointing out the importance of understanding the kinetics of particle internalization. In this context, the uptake kinetics of representative airborne NPs over 30 min and their internaliz ...
Cerium oxide nanoparticles (CNPs) represent a promising class of antioxidant nanoparticles with potential therapeutic value. Due to the easily reversible oxidation states of cerium (Ce3+ and Ce4+) at the nanoscale, CNPs scavenge excessive reactive oxygen and nitrogen species in a self-regenerative manner. In this study, we have demonstrated a simple method to functionalize shape-specific CNPs (i.e., rod- and cube-shaped) with polyethylene glycol (PEG) and studied the effect of PEGylation on the ...
At the onset of radiation exposure, free radicals are formed through ionizing reactions that are then capable of destroying normal tissues. While cells release a level of protective molecules, such as glutathione and metallothionine, they are not capable of blocking all damage, thus resulting in the death of normal tissues and therefore, we must continue to develop strategies to protect normal tissues from radiation-induced damage. One such strategy is the development of radiation protectors. Se ...
Soil texture has been found to be a critical factor in regulating the fate and transport of cerium oxide nanoparticles (CeONPs) in the terrestrial environment. However, the underlying mechanisms for the interactions between CeONPs and different components of soil are still poorly understood. The attachment of CeONPs onto two typical components of soil (sand and kaolin) in batch experiments were investigated to provide insights into the retention and bioavailability of CeONPs in soil. Surface pro ...
The key challenge that has limited the industrial utilization of nano-sized metal catalysts is their poor thermal stability and the resulting performance degradation. Here, we address this issue by designing a post-encapsulated composite structure in which individual Pt nanoparticles are surrounded by gas-permeable and catalytically active CeO2 shells. Positively charged surfactants on the nanoparticle surfaces are exploited to adsorb negatively charged Ce precursor complexes spontaneously, foll ...
In the recent decades, the change in the air quality caused by pollutant emissions that are harmful to human health and to the environment has been a subject of an increasing concern. Among these pollutants, particulate emissions arising from the incomplete combustion of diesel deserve a special attention due to many adverse health effects, especially on the respiratory system. In view of this scenario, several studies have focused on practical ways to overcome this problem through the developme ...
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Y. H. Liu, J. C. Zuo, X. F. Ren, College of Material Science and Engineering, Shenyang Ligong University, Shenyang,Liaoning, China. L. YONG, School of Material and Metallurgy, Northeastern University, Liaoning, Liaoning, China In this paper cerium oxide (CeO2) nanoparticles with 200-300 nm in diameter were synthesized via a precipitation method using ammonia water and oxalic acid as precipitant, respectively. The as-prepared CeO2 nanoparticles were characterized by means of diff erent techniques ...
Cerium oxide nanomaterials (CeNMs), due to their excellent scavenging properties of reactive oxygen species (ROS), have gained great promise for therapeutic applications. A high level of ROS often degrades the potential of stem cells in terms of survivability, maintenance and lineage differentiation. Here we hypothesize the CeNMs may play an important role in protecting the capacity of stem cells against the oxidative insult, and the suppression mechanism of ROS level may depend on the internali ...
We have studied the stoichiometry of cerium oxide films deposited by RF sputtering on sapphire and MgO as a function of deposition conditions using the resonant Rutherford backscattering method. We found that some films have the off-stoichiometry of CeO/sub y/ with y greater than 2.0. Such an off-stoichiometry cannot be due to a mixture of the known phases of bulk cerium oxide samples. This may be due to either cerium vacancies or interstitial oxygen atomic impurities. The cerium ion X-ray photo ...
The aim of the present study was to assess the acute toxic potential of cerium oxide nanoparticles (CeO(2) NPs) in rats when exposed through the head and nose inhalation route. The rats were exposed to CeO(2) NPs and the resultant effects if any, to cause cytotoxicity, oxidative stress and inflammation in the lungs were evaluated on a 24h, 48h and 14 day post exposure period. Our results showed a significant decrease in the cell viability, with the increase of lactate dehydogenase, total protein ...
Cerium oxide nanoparticles (nanoceria) are effective in scavenging intracellular reactive oxygen species (ROS). In this study nanoceria synthesized by flame spray pyrolysis (dXRD = 12 nm) were functionalised with heparin via an organosilane linker, 3-aminopropyltriethoxysilane. Nanoceria were functionalised with approximately 130 heparin molecules per nanoparticle as determined by thermo gravimetric analysis. Heparin functionalised nanoceria were more effectively internalised by the human monocy ...
To date, guidance on how to incorporate in vitro assays into integrated approaches for testing and assessment of nanomaterials is unavailable. In addressing this shortage, this review compares data from in vitro studies to results from in vivo inhalation or intratracheal instillation studies. Globular nanomaterials (ion-shedding silver and zinc oxide, poorly soluble titanium dioxide and cerium dioxide, and partly soluble amorphous silicon dioxide) and nanomaterials with higher aspect ratios (mul ...
We investigated the preparation of well-dispersed core-shell ceria-poly(vinylpyrrolidone) (PVP) nanoparticles with an average particle size of around 20 nm which were used to produce a hybrid film with a polymer coating of dipentaerythritol hexaacrylate (DPHA). We obtained good dispersion of the nanoparticles in a mixed solvent of 48% 1-methoxy-2-propanol (MP), 32% 3-methoxy-3-methyl-1-butanol (MMB), and 20% methyl i-butyl ketone (MIBK). An ink of the polymer coating consisting of 68.7 wt% nanop ...
The unique catalytic properties of ceria for the partial hydrogenation of alkynes are examined for acetylene hydrogenation. Catalytic tests over polycrystalline CeO2 at different temperatures and H2/C2H2 ratios reveal ethylene selectivities in the range of 75−85% at high degrees of acetylene conversion and hint at the crucial role of hydrogen dissociation on the overall process. Density-functional theory is applied to CeO2(111) in order to investigate reaction intermediates and to calculate th ...
This study was conducted to determine the effects of dietary cerium oxide levels (0, 100, 200, 300 or 400 mg/kg) on the laying performance, egg quality, some blood serum parameters and egg lipid peroxidation of laying hen. In total, one hundred and twenty 22-week-old brown Lohman LSL laying hens were randomly assigned to five groups equally (n = 24). Each treatment was replicated six times. Dietary supplementation of cerium oxide had no significant effect on feed intake and egg weight. The ad ...
It is very important to have a good understanding of the biological effects of nanoparticles (NPs) on marine diatoms. In this study, the physiological and biochemical responses of a marine diatom Phaeodactylum tricornutum to titanium dioxide NPs (nano-TiO2) and cerium oxide NPs (nano-CeO2) were compared and evaluated using 96h growth tests in a batch-culture system. At 96h of exposure, the growth inhibition rate (IR, %) of P. tricornutum increased from 5.46 to 27.31% with increasing nano-TiO2 co ...