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This study investigates the potential of combining Cerium-doped bioactive glass (BBGi) with Polyvinylpyrrolidone (PVP) to enhance the properties of titanium (Ti) implant surfaces using the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique. The primary focus is on improving osseointegration, corrosion resistance, and evaluating the cytotoxicity of the developed thin films towards host cells. The innovative approach involves synthesizing a composite thin film comprising BBGi and PVP, leveraging the distinct benefits of both materials: BBGi's biocompatibility and osteoinductive capabilities, and PVP's film-forming and biocompatible properties. Results demonstrate that the BBGi + PVP coatings significantly enhance hydrophilicity, indicating improved cell-material interaction potential. The electrochemical analysis reveals superior corrosion resistance of the BBGi + PVP films compared to BBGi alone, which is critical for long-term implant stability. The mechanical adherence tests confirm the robust attachment of the coatings to Ti substrates, surpassing the ISO standards for implant materials. Biocompatibility tests show promising cell viability and negligible cytotoxic effects, with a controlled inflammatory response, underscoring the potential of BBGi + PVP coatings for orthopedic applications. The study concludes that the synergistic combination of BBGi and PVP, applied through the MAPLE technique, offers a promising route to fabricate bioactive and corrosion-resistant coatings for Ti implants, potentially enhancing osseointegration and longevity in clinical settings., (Creative Commons Attribution license.)

This work aims to develop a bio-based fibrous material that is able to adsorb and degrade chemical and biological hazardous agents. Thus, cellulosic fabrics (flax) were functionalized with chitosan (CS) and poly(ethylene oxide) (PEO) electrospun nanofibers doped with titanium dioxide (TiO 2 ) and cerium dioxide (CeO 2 ) nanoparticles (NPs). The electrospray deposition of these NPs was also tested. The TiO 2 NPs were synthesized using a very straightforward precipitation method. The successful synthesis was confirmed by Scanning Transmission Electron Microscopy (STEM) and Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FTIR). The functionalization of the fabrics with the NPs and the nanofibers doped with NPs was proved by Field Emission Scanning Electron Microscopy (FESEM), ATR-FTIR, and Ground-State Diffuse Reflectance (GSDR). The developed samples presented antibacterial activity against Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 434), reaching values of 99.97 and 100.0 %, respectively. The degradation of methylene blue (MB) and dimethyl methylphosphonate (DMMP) was evaluated. The best samples were able to decompose 97.82 % of DMMP. The wash durability of the nanocoating was also tested. The developed fibrous structures show great potential for personal protection applications., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Diana P. Ferreira reports financial support was provided by Foundation for Science and Technology. Joana C. Araujo reports financial support was provided by Foundation for Science and Technology. Pilar Teixeira reports financial support was provided by Foundation for Science and Technology. Catia L. Graca reports financial support was provided by Foundation for Science and Technology. Olivia Salome G. P. Soares reports was provided by Foundation for Science and Technology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The objective of this study was to synthesize strontium titanate (Sr 1-x Ce x TiO 3 ) doped with Ce 3+ by solid state method. Its crystalline structure is Sr 1-x Ce x TiO 3 , and its bandgap ranges from ~3.3 to ~2.7 eV. In the photoluminescence of samples excited at 288 nm, the maximum emission of blue light was observed at 380 and 390 nm. Photocatalytic results show that dye molecules have a high absorbance, whereas their surface area is large. According to a line sweep voltammetric plot (LSV), illumination increases the current density by 0.4 μA cm -2 compared with dark conditions. It was demonstrated that the material changed from n-type to p-type under doping. Chronoamperometry spectra were obtained for sample Sr 1-x Ce x TiO 3 (x = 0, 0.005, 0.01, 0.03, 0.05) when an electrical voltage of 0.8 V was applied versus NHE. The plots indicate an increase in the current density under "light ON" conditions and a decrease under "light OFF" conditions. As Ce 3+ concentration increases, the photocurrent increases until about 3 mol%, after which it decreases abruptly., (© 2024 John Wiley & Sons Ltd.)

Excessive production of reactive oxygen species (ROS) around titanium implants under diabetic conditions causes persistent inflammation, leading to poor osseointegration and even implant failure. Surface modification is an effective way to promote ROS clearance, alleviate inflammation, and stimulate bone formation. In this study, a multifunctional coating is fabricated by introducing cerium (Ce)-containing mesoporous bioactive glass nanoparticles (Ce-MBGNs) onto the titanium surface via an electrophoretic deposition method. The incorporation of Ce-MBGNs remarkably improves surface hydrophilicity by increasing the surface areas. The bioactive ions are appropriately released, thereby promoting mesenchymal stem cell proliferation and differentiation under diabetic conditions. The conversion between Ce(III) and Ce(IV) endows Ce-MBGNs coating with antioxidative nanoenzymes properties to scavenge diabetes-induced ROS, resulting in macrophage polarization towards the anti-inflammatory phenotype. The therapeutic effect of Ce-MBGNs-modified titanium implants is also verified in diabetic rats by inhibiting inflammatory responses and accelerating early osseointegration. Taken together, the findings reveal that the ROS-scavenging and immunomodulation activity of the Ce-MBGNs coating contributes to enhanced osseointegration, and provides a novel implant surface for diabetic patients., (© 2024. The Author(s).)

Cerium and cobalt loaded Co-Ce/TiO 2 catalyst prepared by impregnation method was investigated for photothermal catalytic toluene oxidation. Based on catalyst characterizations (XPS, EPR and H 2 -TPR), redox cycle between Co and TiO 2 (Co 2+ + Ti 4+ ↔ Co 3+ + Ti 3+ ) results in the formation of Co 3+ , Ti 3+ and oxygen vacancies, which play important roles in toluene catalytic oxidation reaction. The introduction of Ce brings in the dual redox cycles (Co 2+ + Ti 4+ ↔ Co 3+ + Ti 3+ , Co 2+ + Ce 4+ ↔ Co 3+ + Ce 3+ ), further promoting the elevation of reaction sites amount. Under full spectrum irradiation with light intensity of 580 mW/cm 2 , Co-Ce/TiO 2 catalyst achieved 96% of toluene conversion and 73% of CO 2 yield, obviously higher than Co/P25 and Co/TiO 2 . Co-Ce/TiO 2 efficiently maintains 10-hour stability test under water vapor conditions and exhibits better photothermal catalytic performance than counterparts under different wavelengths illumination. Photothermal catalytic reaction displays improved activities compared with thermal catalysis, which is attributed to the promotional effect of light including photocatalysis and light activation of reactive oxygen species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Reducing the cost of RuO 2 /TiO 2 catalysts is still one of the urgent challenges in catalytic HCl oxidation. In the present work, a Ce-doped TiO 2 supported RuO 2 catalyst with a low Ru loading was developed, showing a high activity in the catalytic oxidation of HCl to Cl 2 . The results on some extensive characterizations of both Ce-doped TiO 2 carriers and their supported RuO 2 catalysts show that the doping of Ce into TiO 2 can effectively change the lattice parameters of TiO 2 to improve the dispersion of the active RuO 2 species on the carrier, which facilitates the production of surface Ru species to expose more active sites for boosting the catalytic performance even under some harsh reaction conditions. This work provides some scientific basis and technical support for chlorine recycling., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Pyroelectric nanostructures can effectively generate temperature-mediated reactive oxygen species (ROS) through the pyroelectric effect, providing promise for treating hypoxic tumors; and therefore, the synergistic application of photothermal therapy (PTT) and pyroelectric dynamic therapy (PEDT) presents an intriguing approach for cancer therapy. However, this method still faces challenges in improving pyroelectric catalysis and achieving precise tumor localization. In this study, a nano-heterojunction based on CeO 2 -BaTiO 3 nanorods (IR1061@PCBNR) is reported, which exhibits highly effective pyroelectric catalysis for simultaneous tumor-targeted dynamic therapy and gentle photothermal therapy through the utilization of the rich oxygen vacancies. The oxygen vacancies create active sites that facilitate the migration of pyroelectrically-induced charge carriers, improving charge separation and ROS generation. IR1061@PCBNR also demonstrates high tumor penetration; while, minimizing damage to normal cells. This precise nanomedicine strategy holds great potential for advancing dynamic cancer therapies by overcoming the limitations of conventional approaches., (© 2024 Wiley‐VCH GmbH.)

Compromises between enhanced on-targeting reactivity and precise real-time monitoring in the tumor microenvironment (TME) are the main roadblocks for catalytic cancer therapy. The hallmark of a high level of hydrogen peroxide (H 2 O 2 ) and acidic extracellular environment of the hypoxia solid tumor can underpin therapeutic and tracking performance. Herein, this work provides an activatable wintersweet-like nanohybrid consisting of titanium (Ti) doped cerium vanadate nanorods with the modification of polypyrrole (PPy) nanoparticles (CeVO 4 -Ti@PPy) for combinatorial therapies of breast carcinoma. The Ti dopants in the size-controllable CeVO 4 nanorods lower the energy barrier (0.5 eV) of the rate-determining steps and elaborate peroxidase-like (POD-like) activities to improve the generation of toxic hydroxyl radical (·OH) according to the density functional theory (DFT) calculation. The multiple enzyme-like activities, including the intrinsic glutathione peroxidase (GPx) and catalase (CAT), achieve a record-high therapeutic efficiency. Coupling this oxidative stress with the photothermal effects of PPy enables enhanced catalytic tumor necrosis. The exterior PPy heterogeneous structure can be further doped with protons in the local acidic environment to intensify photoacoustic signals, allowing the non-invasive accurate tracking of tumors. The theranostic performance displayed negligible attenuated signals in near-infrared (NIR) windows. This organic-inorganic nanohybrid with a heterogeneous structure provides the potential to improve the overall outcomes of catalytic therapy., (© 2024 Wiley‐VCH GmbH.)

NH 3 -SCR (SCR: Selective catalytic reduction) is an effective technology for the de-NO x process from both mobile and stationary pollution sources, and the most commonly used catalysts are the vanadia-based catalysts. An innovative V 2 O 5 -CeO 2 /TaTiO x catalyst for NO x removal was prepared in this study. The influences of Ce and Ta in the V 2 O 5 -CeO 2 /TaTiO x catalyst on the SCR performance and physicochemical properties were investigated. The V 2 O 5 -CeO 2 /TaTiO x catalyst not only exhibited excellent SCR activity in a wide temperature window, but also presented strong resistance to H 2 O and SO 2 at 275 ℃. A series of characterization methods was used to study the catalysts, including H 2 -temperature programmed reduction, X-ray photoelectron spectroscopy, NH 3 -temperature programmed desorption, etc. It was discovered that a synergistic effect existed between Ce and Ta species. The introduction of Ce and Ta enlarged the specific surface area, increased the amount of acid sites and the ratio of Ce 3+ , (V 3+ +V 4+ ) and O α , and strengthened the redox capability which were related to synergistic effect between Ce and Ta species, significantly improving the NH 3 -SCR activity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Configuring Co-based catalysts with excellent activity, durability, anti-H 2 O capability and superior chlorine resistance is an effective strategy for catalytic combustion of CVOCs. In this work, we elaborated a CoCuO x catalysts with the same core but different shell. The CoCuO x dodecahedron surface was successfully coated with shells of Nb 2 O 5 , TiO 2 , and CeO 2 using a range of conventional synthesis methods. The prepared core-shell catalysts (CoCuO x @TiO 2 and CoCuO x @Nb 2 O 5 ) were found to generate plentiful acid sites and abundant lattice oxygen species, indicating a strong interaction between the core and shell layers that resulted in a significant enhancement of catalytic activity. Additionally, by-products generation was successfully controlled by acid sites and lattice oxygen species. More importantly, the core-shell structure design significantly improved the thermal stability and anti-H 2 O capability of the catalysts. Furthermore, the possible formation pathways and reaction mechanisms were proposed based on in-situ FTIR and selectivity analysis., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

Deoxynivalenol (DON) is a major mycotoxin with high toxicity that often contaminates grains, foods and feeds. The traditional approaches for DON removal are difficult to meet industry and agriculture demands due to the high stability of the DON molecule. Therefore, there is an urgent need to develop green and effective strategies for DON degradation. In this study, a batch of photocatalytic nanomaterials of cerium (Ce) doped titanium dioxide (TiO 2 ) were successfully prepared by sol-gel method. The catalysts were systematically characterized by XRD, HRTEM, FT-IR, UV-Vis and XPS. The catalyst 0.5Ce-TiO 2 showed superior photocatalytic activity for DON degradation in aqueous solution under ultraviolet light irradiation, better than that of traditional photocatalyst pure TiO 2 , and 96% DON with initial concentration of 5.0 mg/L could be degraded in 4 h. In addition, the two possible degradation intermediate products C 5 H 8 O 3 and C 17 H 18 O 6 were identified, the photocatalytic degradation mechanism and degradation pathway were studied. The results indicate that Ce doped TiO 2 photocatalyst can be used to reduce DON effectively.

Fibrous Ti/Ce oxide photocatalysts were prepared for the first time by a biomimetic solution process using short flax fibers (flax straw processing waste) as a biotemplate. Titanium polyhydroxy complex solutions with 3% and 5% cerium were used as precursors. Flax fibers were impregnated in an autoclave under hydrothermal conditions. Ti/Ce oxides were obtained from the biotemplate by annealing at 600 °C. The photocatalytic activity of the Ti/Ce oxides was studied by the adsorption and decomposition of the dye rhodamine B under UV irradiation. The photocatalytic decomposition of the dye was 50% and 75% faster for Ti/Ce oxides with 3% and 5% Ce, respectively, than for the analogous undoped fibrous TiO 2 . The morphologies, textures, and structures of the photocatalysts were studied by scanning electron microscopy, low temperature N 2 adsorption/desorption, UV-Vis spectroscopy, and X-ray and XPS analytical methods. It was shown that the introduction of Ce into the precursor solution increased the surface irregularity of the Ti/Ce oxide crystallites compared to pure TiO 2 . This effect scaled with the Ce concentration. Ce improved the UV light absorption of the material. The Ti/Ce oxides contained Ce 4+ /Ce 3+ pairs that played an important role in redox processes and intensified the photocatalytic activity.

This article aims to explore interaction of nanoparticles ZnO, TiO 2 and CeO 2 with bovine serum albumin (BSA). The samples of nanoparticles were laboratory prepared and compared with commercial nanoparticles. Nanoparticles were characterized by SEM, zeta potential and size measurements. Adsorption of particles took place at pH where the zeta potential of the protein and nanoparticles was opposite. Then the zeta potential and size distribution were measured and the amount of protein needed to reduce the zeta potential of nanoparticles to zero was determined. The changes of BSA structure were also observed by Circular Dichroism (CD). The change of BSA structure after the adsorption on nanoparticles was confirmed. The content of BSA α-helix structure varies during experiments from 13 to 77% in dependence of concentration of nanoparticles. The interaction of TiO 2 and BSA was confirmed also by the Surface Plasmon Resonance (SPR) technique. On laboratory prepared TiO 2 was bound amount of 73,4 pg·mm -2 ., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Nano-heterostructures of titanate nanotubes were synthesized and they revealed a complex structure with the formation of TiO 2 (anatase), CeO 2 , Ag 2 O and metallic silver nanoparticles on the outer walls and intercalation of Ce 4+ and Ag + into the interlayer spaces of the nanotubes by microwave-assisted hydrothermal process and subjected to ion exchange reactions. To the best of our knowledge, this is the first reported silver and cerium co-exchanged titanate nanotubes for bio-applications. The co-ion exchange processes preserved the original tubular structure of titanate nanotubes with significant changes of the superficial as well as interlamellar environment. This study opens up possibility of synthesizing complex, functional nano-heterostructure with the scope of modification of the final structure, especially the amount and oxidation state of the intercalated cation (Ce 4+ , Ce 3+ and Ag + ) as well as the quantity and variety of the decorating nanoparticles (CeO 2 , Ag 2 O or metallic Ag). The interplay of which, in turn, can lead to important biological properties and applications, owing to their ion-liberation capacity. The samples were tested in antibacterial activity with two different kind of bacteria (gram positive and negative), cell cytotoxicity and adhesion, and it was found that the nano-heterostructure formed shows high antibacterial activity with low cytotoxicity and high cell adhesion, which makes it a promising material for further health applications., Competing Interests: Declaration of competing interest On behalf of the authors of the article “Synthesis of Silver-Cerium Titanate Nanotubes and their surface properties and antibacterial applications”, I certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Low-energy x-ray imaging of secondary electron bremsstrahlung x-rays emitted during carbon-ion irradiation is a promising method for range estimation and could be used for imaging with almost clinical dose levels of carbon ion. However, the number of counts in images with clinical dose levels is relatively small, making it difficult to obtain precise range estimations. Since improving the sensitivity of the x-ray camera may solve this issue, we developed two new types of x-ray cameras. One uses a 1 mm thick, 40 mm × 40 mm cerium-doped yttrium aluminum perovskite (YA1O 3 : YAP(Ce)) scintillator plate combined with a 2 inch square flat panel photomultiplier tube (FP-PMT) contained in a 2 cm thick tungsten shield with a pinhole collimator positioned 50 mm from the scintillator; the other uses a 0.5 mm thick, 20 mm × 20 mm YAP(Ce) scintillator plate combined with a 1 inch square position sensitive photomultiplier tube (PSPMT) contained in the same tungsten shield with a pinhole collimator, but with the scintillator positioned closer (30 mm) to the pinhole collimator to obtain a similar field of view. For both cameras, we used a wider angle (∼55°) pinhole collimator to measure the phantom closer to improve sensitivity. Although the 40 mm × 40 mm YAP(Ce) camera had high system spatial resolution, the background count fractions were high and produced a high count area at the center of the images due to the pulse pileup of the signals. With the 20 mm × 20 mm YAP(Ce) camera, we obtained x-ray images with low background counts without a high count area at the image center. By smoothing the measured images, we were able to estimate the ranges even for clinical dose levels. We therefore confirmed that one of our newly developed YAP(Ce) cameras had high sensitivity and is promising for the imaging of secondary electron bremsstrahlung x-rays during irradiation of carbon ions in clinical conditions.

The cytotoxic and genotoxic effects of titanium dioxide (TiO2) nanoparticles when exposed to ultraviolet (UV) radiation, particularly wavelengths between 320-400 nm, has raised concern over their safe use in health and cosmetic related products such as sunscreens. Cerium dioxide (CeO2) nanoparticles have been demonstrated to display biocompatible properties and antioxidant activity due to redox cycling of the Ce3+/Ce4+ oxidation states. In this work, CeO2/TiO2 nanocomposites were prepared through a standard precipitation method at atomic concentrations (at%) of Ce relative to Ti of 2.5, 5 and 10 at%, with the aim of reducing the photocatalytic activity of the core TiO2 nanoparticles and improve biocompatibility. The UV absorptive properties of the nanocomposite samples revealed excellent absorbance across the UV region as compared to pristine TiO2 and CeO2. Furthermore, a drastic reduction in the photocatalysed decomposition of crystal violet, when in the presence of the nanocomposite samples, under both UV and solar simulated light was observed compared to the highly photoactive pristine TiO2. An optimal CeO2 nanodot loading, displaying both high UV attenuation and low photocatalytic performance was determined at 5 at% and further in vitro biological testing revealed minimal impact on the cell viability of the human keratinocyte cell line (HaCaT) over a 24 h period with and without prior exposure to UV irradiation. In contrast, pristine TiO2 nanoparticles induced toxicity to HaCaT cells with prior UV exposure before incubation, particularly at a dosage of 100 mg L-1. Our findings demonstrate the effectiveness of CeO2 nanodots in improving biocompatibility and its potential as a coating material for active inorganic UV filters.

This work investigates the effect of cerium substation into strontium cobalt perovskites (CeSrCoO) for the oxidative degradation of Orange II (OII) in dark ambient conditions without the aid of any external stimulants such as light, heating or chemical additives. The OII degradation rate by CeSrCoO reached 65% in the first hour, whilst for the blank sample without cerium (SrCoO) took over 2 hr to reach the same level of OII degradation. Hence, the cerium substitution improved the catalytic activity of the perovskite material, mainly associated with the Ce 0.1 Sr 0.9 CoO 3 perovskite phase. Upon contacting CeSrCoO, the -NN- azo bonds of the OII molecules broke down resulting in electron donation and the formation of by-products. The electrons are injected into the CeSrCoO and resulted in a redox pair of Co 3+ /Co 2+ , establishing a bridge for the electron transfer between OII and the catalysts. Concomitantly, the electrons also formed reactive species (·OH) responsible for OII degradation as evidenced by radical trapping experiment. Reactive species were formed via the reaction between O 2 and donated electrons from OII with the aid of cobalt redox pair. As the prepared materials dispensed with the need for light irradiation and additional oxidants, it opens a window of environmental applications for treating contaminated wastewaters., (Copyright © 2019. Published by Elsevier B.V.)

Cerium titanate catalyst (Ce-TiO 2 ) is competitive as a substitute for the commercial SCR (selective catalytic reduction) catalysts VO 5 -WO 2 /TiO 2 due to its high SCR activity and excellent redox performance. The reaction mechanisms of Ce-TiO 2 at 180 °C, 240 °C, and 300 °C in the presence of SO 2 were systematically studied regarding the evolution of the SCR activity, quantitative analysis of sulfate compounds, and comprehensive identification of the fresh and poisoned catalysts. The results demonstrated that NO conversion at 180 °C in the presence of SO 2 is highly sensitive to the formation of cerium sulfates/sulfites, limiting the reactivity of NH 4 + adsorbed on SO Brønsted acid sites and inhibiting the E-R reaction pathway. At 240 °C, the degradation of NO conversion was commenced by the cumulative influence of cerium sulfates/sulfites. With the increase of the reaction temperature to 300 °C, the NO conversion is gradually immune to the formation of cerium sulfates in spite of the great amount of cerium sulfates deposited on the deeper interior of CeO 2 . The high SCR activity of the Ce-TiO 2 catalyst in the presence of SO 2 at a higher reaction temperature might be ascribed to the synergistic catalysis between surface cerium sulfates and bulk CeO 2 , where surface cerium sulfates act as acid sites for the adsorption of NH 3 and the bulk CeO 2 acts as the redox sites. The reaction mechanisms of the Ce-TiO 2 catalyst in the presence of SO 2 at different temperatures are proposed as the two reaction routes., Competing Interests: Declaration of competing interest None., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Metal-derived nanoparticles (Mt-NPs) are increasingly used in cosmetology due to their ultraviolet shielding (titanium dioxide [TiO 2 ]), antioxidant (cerium dioxide [CeO 2 ]), and biocidal (silver [Ag]) properties. In the absence of overt toxicity (i.e., cell death), Mt-NPs are considered safe for cosmetic applications. However, there is little understanding about the mechanisms involved in the survival of keratinocytes exposed to subtoxic levels of Mt-NPs. Human keratinocytes (HaCaT) were exposed subacutely to subtoxic concentrations (≤30 μg/mL, 48-72 h) of rutile (r) TiO 2 (cylindrical), CeO 2 (cubic) and Ag (spherical) with a core/hydrodynamic size of <50/<100 nm and >98% purity. Mt-NP uptake was indirectly quantified by changes in the light side scatter, where the kinetics (time/dose-response) suggested that the three types of Mt-NPs were similarly uptaken by keratinocytes. rTiO 2 and CeO 2 , but not Ag-NPs, increased autophagy, whose inhibition prompted cell death. No increase in the steady-state levels of reactive oxygen species (ROS) was induced by exposure to any of the Mt-NPs tested. Interestingly, intracellular Ag-NP aggregates observed an increased far-red autofluorescence (≥740 nm em), which has been ascribed to their binding to thiol molecules such as glutathione (GSH). Accordingly, inhibition of GSH synthesis, but not the impairment of oxidized GSH recycling, sensitized keratinocytes to Ag-NPs suggesting that GSH homeostasis, and its direct scavenging of Ag-NPs, but not ROS, is essential for keratinocyte survival upon exposure to Ag-NP. rTiO 2 and Ag, but not CeO 2 -NPs, compromised metabolic flux (glycolysis and respiration), but ATP levels were unaltered. Finally, we also observed that exposure to Mt-NPs sensitized keratinocytes to non-UV xenobiotic exposure (arsenite and paraquat). Our results demonstrate the differential contribution of autophagy and GSH homeostasis to the survival of human keratinocytes exposed to subtoxic concentrations of Mt-NPs and highlight the increased susceptibility of keratinocytes exposed to Mt-NPs to a second xenobiotic insult.

Waste is a misplaced resource. Herein, anionic (orange II sodium salt and Ponceau 2R) and cationic (Rhodamine B and Methylene blue) dye wastewater assisted photo-treatment (referred as DAPT) method was developed to modify sol-gel synthesized CeO 2 -TiO 2 (CeTi) mixed oxide catalyst. Catalytic activity test results showed that both anionic and cationic dye wastewater could be used as "fuel" of photo-treatment to enhance the activity of CeTi catalyst in NO reduction and dichloromethane oxidation. Characterization and DFT calculation results revealed that DAPT process increased the amount of Ce 3+ ions on CeTi samples, which could induce the formation of Ce-V O -Ti (oxygen vacancy (V O ) in Ce-O-Ti short range structure). These Ce-V O -Ti defects not only could be adsorption sites for NH 3 , dichloromethane and oxygen, but also promoted the redox shift of Ce 3+ + Ti 4+ ⇋ Ce 4+ + Ti 3+ by enhancing the oxidizability of Ce 4+ and Ti 4+ species. Furthermore, defects changed the polarity of Ce-O and Ti-O, which was conducive to the activation of lattice oxygen. All these improvements contributed to the excellent catalytic activity of CeTi catalysts. We expected this work to be instructive on constructing structure-activity over CeO 2 -TiO 2 based catalysts and utilizing dye wastewater., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Peri-implantitis is the most common risk factor for dental implant failure. Nanostructured ceria (nano-CeO 2 ) has anti-inflammatory and antibacterial functions, and different shapes of ceria enclosed by specific crystal planes could be an effective approach to enhance intrinsic catalysis. In the present study, the authors developed a novel implant surface-modification strategy by coating different shapes of nano-CeO 2 onto titanium (Ti) surfaces to enhance their antibacterial and anti-inflammatory properties. The objectives of the study were to: (1) develop novel Ti surfaces modified with different shapes of nano-CeO 2 (nanorod, nanocube and nano-octahedron) for peri-implantitis prevention; (2) investigate and compare the inhibition efficacy of different shapes of CeO 2 -modified surfaces against biofilms of peri-implantitis-related pathogens; and (3) evaluate the different CeO 2 -modified surfaces on cell inflammatory response in vitro and in vivo. The results showed that nanorod CeO 2 -modified Ti had more bacteria attachment of Streptococcus sanguinis in the early stage, compared with other CeO 2 -modified Ti (p < 0.05). They all exhibited similarly substantial CFU reductions against peri-implantitis-related biofilms (p > 0.1). Nanocube and nano-octahedron CeO 2 -modified Ti exerted much better anti-inflammatory effects and ROS-scavenging ability than nanorod CeO 2 in vitro (p < 0.05). In vivo, the mean mRNA expression of TNF-α, IL-6 and IL-1β in the tissues around Ti was decreased by the three shapes of nano-CeO 2 ; nano-octahedron CeO 2 showed the strongest anti-inflammatory effect among all groups (p < 0.05). In conclusion, all three types of CeO 2 -modified Ti exerted equally strong antibacterial properties; nano-octahedron CeO 2 -modified Ti had the best anti-inflammatory effect. Therefore, CeO 2 -modified Ti surfaces are highly promising for enhancing antimicrobial functions for dental implants. Novel nano-octahedron CeO 2 coating on Ti had great therapeutic potential for alleviating and eliminating peri-implantitis. STATEMENT OF SIGNIFICANCE: Peri-implantitis is the most common risk factor for dental implant failure. Nanostructured ceria (nano-CeO 2 ) has anti-inflammatory and antibacterial functions, and different shapes of ceria enclosed by specific crystal planes could be an effective approach to enhance intrinsic catalysis. In the present study, we developed a novel implant surface-modification strategy by coating different shapes of nano-CeO 2 onto titanium surfaces to enhance their antibacterial and anti-inflammatory properties for dental implants. In addition, we found that the nano-octahedron CeO 2 coating on titanium would have great therapeutic potential for alleviating and eliminating peri-implantitis., (Copyright © 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

The ozone initiated oxidation of 1,3,7-trimethylxanthine (caffeine), commonly found in wastewaters as model compound is reported using cerium (Ce)/titanium dioxide (TiO 2 ) as catalyst. The effect of pH and loading of ceria on titania were investigated. Effect of reaction conditions on degradation of caffeine based on their pseudo first-order rate constants were compared. The combination of catalyst Ce-TiO 2 and ozone aeration significantly enhanced the degradation of caffeine compared to uncatalysed ozonation. The oxidation of caffeine ensued via the free radical mechanism, through enhanced ozone decomposition into OH radicals. Ce/TiO 2 (0.5 wt%) showed good activity in degradation of caffeine at pH 6, in both natural stream and river water samples showing about 60% total organic carbon removal in 2 h ozonation period. Using liquid chromatography-mass spectroscopy, degradation products were analysed. A reaction intermediate and one final product were positively identified. Nano-catalysts with different loadings of Ce on TiO 2 synthesized by sol-gel route were characterized by scanning electron microscope, transmission electron microscopy, BET and powder X-ray diffraction spectrum techniques. The results showed that the material retained a highly ordered mesoporous structure and possessed large surface area.

In recent years, significant effort has been made in the development of novel catalysts for the total oxidation of chlorinated volatile organic compounds. In this work the catalytic activity of Cu doped cerium-titanium binary oxides for the oxidation of dichloromethane (DCM) have been studied for the first time. Combining catalysts characterization and activity data, it was found that Cu ions can uniformly disperse into titanium dioxide to form solid solution and induce the creation of additional surface oxygen species on the catalysts surface, while moderate amount of Ce ions are still needed for the activation of CCl. Detailed analysis of the in-situ FTIR experiment results revealed that the surface oxygen species, especially the hydroxyl groups associated with Cu ions, can promote the deep oxidation of the intermediate species formed in the nucleophilic substitution process occurred on the active sites of catalysts surface. The sample with the Cu/Ce molar ratio of 1:3 obtained a better CO 2 selectivity than that reached with cerium-titanium binary oxides. Meanwhile, according to element balance analysis, removal of chlorine from the catalyst surface was also promoted by Cu doping., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The objective of the present study was to assess hard and soft tissue around dental implants made of three different materials with microgrooves on the collar surface. Microgrooved implants were inserted in the mandibles of five male beagles. Implants were made of three kinds of material; titanium (Ti), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria partially stabilized zirconia/alumina nanocomposite (Ce-TZP/Al 2 O 3 ). The animals were euthanatized at three months after implantation, and harvested tissue was analyzed by means of histology. All kinds of implant were osseointegrated, and there were no significant differences in any histomorphometric parameters among the three groups of microgrooved implants made of different materials. Within the limitations of this study, implants with microgrooves integrated into the surrounding bone tissue, without statistically significant differences among the three tested materials, Ti, Y-TZP, and Ce-TZP/Al 2 O 3 .

We investigated the emission property of perovskite CaHfO 3 polycrystals with various concentrations of cerium ion (Ce 3+ ). With a wide range of UV photoexcitation, we observed a strong emission near 430 nm which should originate from 5d-4f transitions in the Ce 3+ ions. Combining these emission spectra with the photoluminescence excitation spectra, we estimated the Stokes shift to be 6700 cm -1 , irrespective of the Ce 3+ ion doping concentration. We found that the violet-blue emissions in Ce 3+ ions showed non-trivial temperature dependence in their peak position and intensity. We found interesting low-temperature behavior of the violet-blue emission, which might be attributed to the thermal lattice effect in CaHfO 3 . We also discussed our results with those of the similar materials, perovskite zirconates. Our systematic studies provide useful information on the host material CaHfO 3 for a future study on the violet-blue emission of Ce 3+ ions., (© 2018 John Wiley & Sons, Ltd.)

The effect of K deactivation on V 2 O 5 /WO 3 -TiO 2 and Ce-doped V 2 O 5 /WO 3 -TiO 2 catalysts in the selective catalytic reduction (SCR) of NO x by NH 3 was studied. Ce-doped V 2 O 5 /WO 3 -TiO 2 showed significantly higher resistance to K deactivation than V 2 O 5 /WO 3 -TiO 2 . Ce-doped V 2 O 5 /WO 3 -TiO 2 with K/V=4 (molar ratio) showed 90% NO x conversion at 350°C, whereas in this case V 2 O 5 /WO 3 -TiO 2 showed no activity. The fresh and K-poisoned V 2 O 5 /WO 3 -TiO 2 and Ce-doped V 2 O 5 /WO 3 -TiO 2 catalysts were investigated by means of in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), NH 3 -temperature progress decomposition (NH 3 -TPD), X-ray photoelectron spectroscopy (XPS) and H 2 -temperature program reduction (H 2 -TPR). The effect of Ce doping on the improving resistance to K of V 2 O 5 /WO 3 -TiO 2 were discussed., (Copyright © 2018. Published by Elsevier B.V.)

Lanthanide perovskite catalysts doped with limited palladium (to improve activity) and cerium (to improve sulfur resistance) were prepared using sol-gel method. In different B sites, lanthanide perovskites were studied at harsh conditions for H 2 selective catalytic reduction of NO. The activity sequence was as follows: LaCeMnPd > LaCeCoPd > LaCeFePd. LaCeMnPd had a high NO conversion of 96.6% at only 150 °C. And it also had a surprising SO 2 resistance in different SO 2 concentrations. After cutting out SO 2 , NO conversion recovered rapidly to its original level, indicating that the slight deactivation was reversible. In addition, the effect of gas hourly space velocity, H 2 /NO ratio, O 2 , and SO 2 concentration was studied. And XRD, energy-dispersive X-ray, SEM, XPS, H 2 -temperature programmed reduction, and NH 3 -temperature programmed desorption were performed to characterize the catalysts. Graphical abstract ᅟ.

A recyclable titanium nanofibers, doped with cerium and nickel doped was successfully synthesized by using sol-gel and electrospinning method for hydrogen generation from alkali free hydrolysis of NaBH 4 . The resultant nanocomposite was characterized to find out the structural and physical-chemical properties by a series of analytical techniques such as FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), SEM (scanning electron microscope), EDX (energy-dispersive X-ray spectroscopy),N 2 adsorption-desorption and BET (Brunauer-Emmett-Teller), etc. The results revealed that cerium and nickel nanoparticles were homogeneously distributed on the surface of the TiO 2 nanofibers due to having similar oxidation state and atomic radium of TiO 2 nanofibers with CeO 2 and NiO for the effective immobilization of metal ions. The NiO doped catalyst showed superior catalytic performance towards the hydrolysis reaction of NaBH 4 at room temperature. These catalysts have ability to produce 305 mL of H 2 within the time of 160 min at room temperature. Additionally, reusability test revealed that the catalyst is active even after five runs of hydrolytic reaction, implying the as-prepared NiO doped TiO 2 nanofibers could be considered as a potential candidate catalyst for portable hydrogen fuel system such as PEMFC (proton exchange membrane fuel cells)., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Effects of functionalization and grafting of TiO 2 , CeO 2 , and SiO 2 nanoparticles (NPs) were investigated, and toxicity of pristine, functionalized, and grafted NP towards Daphnia magna was measured. Surface functionalization of NP with amine groups decreased hydrophobicity of NP. When NPs were hydrophilic, they were less toxic than hydrophobic NP towards D. magna. Grafting agents influenced toxicity: no toxicity of NP was observed when bio-based and hydrogenated synthetic polymers were used, whereas perfluorinated polymers induced a higher toxicity.

Background: Animal models remain at that time a reference tool to predict potential pulmonary adverse effects of nanomaterials in humans. However, in a context of reduction of the number of animals used in experimentation, there is a need for reliable alternatives. In vitro models using lung cells represent relevant alternatives to assess potential nanomaterial acute toxicity by inhalation, particularly since advanced in vitro methods and models have been developed. Nevertheless, the ability of in vitro experiments to replace animal experimentation for predicting potential acute pulmonary toxicity in human still needs to be carefully assessed. The aim of the study was to evaluate the differences existing between the in vivo and the in vitro approaches for the prediction of nanomaterial toxicity and to find advanced methods to enhance in vitro predictivity. For this purpose, rats or pneumocytes in co-culture with macrophages were exposed to the same poorly soluble and poorly toxic TiO 2 and CeO 2 nanomaterials, by the respiratory route in vivo or using more or less advanced methodologies in vitro. After 24 h of exposure, biological responses were assessed focusing on pro-inflammatory effects and quantitative comparisons were performed between the in vivo and in vitro methods, using compatible dose metrics., Results: For each dose metric used (mass/alveolar surface or mass/macrophage), we observed that the most realistic in vitro exposure method, the air-liquid interface method, was the most predictive of in vivo effects regarding biological activation levels. We also noted less differences between in vivo and in vitro results when doses were normalized by the number of macrophages rather than by the alveolar surface. Lastly, although we observed similarities in the nanomaterial ranking using in vivo and in vitro approaches, the quality of the data-set was insufficient to provide clear ranking comparisons., Conclusions: We showed that advanced methods could be used to enhance in vitro experiments ability to predict potential acute pulmonary toxicity in vivo. Moreover, we showed that the timing of the dose delivery could be controlled to enhance the predictivity. Further studies should be necessary to assess if air-liquid interface provide more reliable ranking of nanomaterials than submerged methods.

Nanoparticles of some of the metal oxides are known to have high UV protective efficiency. The UV filtering efficiency of nanoparticles invariably depends on their size and stability in the dispersion. In the present work, a stable dispersion of nanoparticles of three metal oxides, zinc oxide (ZnO), cerium oxide (CeO 2 ) and titanium dioxide (TiO 2 ), was prepared in propylene glycol (PG) using ultrasonication. The method is easy and useful as no additional surfactant or dispersant is needed. The particle size and its distribution was confirmed by Scanning Electron Microscopy and Dynamic Light Scattering. The stability of dispersion was assessed by UV-visible absorption spectroscopy. The UV stability of wood surfaces of Wrightia tinctoria coated with nanodispersions of ZnO, CeO 2 and TiO 2 was evaluated under laboratory conditions in an accelerated weathering tester. Changes in the colour and FTIR spectra of exposed specimens were measured periodically. Rapid colour darkening (yellowing) was observed in uncoated and PG coated specimens. In contrast, nanodispersion coated specimens prevented photo-yellowing considerably with significant reduction in colour changes examined by CIE L*, a*, b* and ΔE*. Increase in concentration of nanoparticles in the dispersion imparted higher resistance to UV induced degradation. However, increased concentration of nanoparticles reduced the transparency of the coating. FTIR analysis indicated rapid degradation of lignin in uncoated and PG coated specimens due to UV exposure. Coating of wood surfaces with nanodispersions restricted lignin degradation. The study also demonstrates the potential of propylene glycol as a dispersant for developing stable and efficient UV protective nanodispersions for wood coating., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A Ce 0.3 TiO x oxide carrier was synthesized via a sol-gel process, and Ce 0.3 TiO x supported metal (M=Cd, Mn, Fe, W, Mo) oxide catalysts were prepared by the method of incipient-wetness impregnation. The catalysts were characterized by means of X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), and Temperature-programmed reduction with H 2 (H 2 -TPR). The catalytic activities for de-NO x were evaluated by the NH 3 -SCR reaction. Among all the catalysts tested, the 2wt.% Cd/Ce 0.3 TiO x catalyst exhibited the best NH 3 -SCR performance, with a wide temperature window of 250-450°C for NO conversion above 90%. Moreover, the catalyst showed N 2 selectivity greater than 99% from 200 to 450°C., (Copyright © 2017. Published by Elsevier B.V.)

In this study, the degradations of 2,3,4,5,6-pentabromotoluene (PBT), 2,3,4,5,6-pentabromoethyl benzene (PBEB), triclosan (TCS) and gemfibrozil (GFZ) in raw hospital wastewater were investigated with cerium (IV) oxide and titanium (IV) oxide nanoparticles considering the mechanisms of adsorption, photolysis, and photocatalysis with UV-C lamps. The effects of nano-CeO 2 and nano-TiO 2 concentrations, irradiation times, UV light powers and hospital wastewater pH on the photodegradation yields of micropollutants namely PBT, PBEB, TCS and GFZ were investigated throughout photocatalysis. The nano-TiO 2 produced had an anatase phase with crystalline shape with a surface area of 205 m 2 g -1 and an average size of 11.50 nm. The CeO 2 nanoparticles had a spherical shape with a higher surface area (302 m 2 g -1 ) than that of TiO 2 and a lower average size (8.11 nm). It was found that the removals of PBT, PBEB, TCS and GFZ with adsorption (5.7%-17.1%) and photolysis (9.0%-15.9%) were not significant for both nanoparticles. The photodegradation of PBT (92%), PBEB (90%), TCS (97%) and GFZ (95%) with nano-CeO 2 gave better results than nano-TiO 2 (90%, 87%, 94% and 93% for PBT, PBEB, TCS and GFZ, respectively) under optimum experimental conditions (0.50 g L -1 nano-CeO 2, 45 min irradiation time, 25 °C temperature, pH = 8.50, 210 W UV light power). Both nanoparticles were reused effectively after photo-removals of the micropollutants from the hospital wastewater. The lowest photodegradation yields were 80%, 78%, 75% and 74% for TCS, GFZ, PBT and PBEB, respectively, with nano-TiO 2 after six sequential treatments. The lowest photodegradation yields were 86%, 83%, 80% and 79% for the same micropollutants, respectively, with nano-CeO 2 after six sequential treatments. The cost to treat 1 m 3 raw hospital wastewater were 8.70 € and 2.28 €, for the photocatalytic treatments with nano-TiO 2 and nano-CeO 2 , respectively.

Photocatalytic oxidation is an attractive method for Hg-rich flue gas treatment. In the present study, a novel cerium-based TiO 2 nanofibers was prepared and selected as the catalyst to remove mercury in flue gas. Accordingly, physical/chemical properties of those nanofibers were clarified. The effects of some important parameters, such as calcination temperature, cerium dopant content and different illumination conditions on the removal of Hg 0 using the photocatalysis process were investigated. In addition, the removal mechanism of Hg 0 over cerium-based TiO 2 nanofibers focused on UV irradiation was proposed. The results show that catalyst which was calcined at 400 °C exhibited better performance. The addition of 0.3 wt% Ce into TiO 2 led to the highest removal efficiency at 91% under UV irradiation. As-prepared samples showed promising stability for long-term use in the test. However, the photoluminescence intensity of nanofibers incorporating ceria was significantly lower than TiO 2 , which was attributed to better photoelectron-hole separation. Although UV and O 2 are essential factors, the enhancement of Hg 0 removal is more obviously related to the participation of catalyst. The coexistence of Ce 3+ and Ce 4+ , which leads to the efficient oxidation of Hg 0 , was detected on samples. Hg 2+ is the final product in the reaction of Hg 0 removal. As a consequence, the emissions of Hg 0 from flue gas can be significantly suppressed. These indicate that combining photocatalysis technology with cerium-based TiO 2 nanofibers is a promising strategy for reducing Hg 0 efficiently., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A novel electrochemiluminescence (ECL) signal-amplified immunosensing strategy was proposed by using gold nanoparticles (Au NPs) functionalized reduced graphene oxide (rGO) capped Fe 3 O 4 (Au-FrGO). In this work, CeO 2 @TiO 2 was prepared by a sol-gel method to wrap CeO 2 with TiO 2 . In the presence of CeO 2 , CeO 2 @TiO 2 exhibited better ECL activity than TiO 2 with peroxydisulfate as coreactant. In addition, FrGO with macroporous structure was synthesized by self-assembly of rGO sheets capped cationic Fe 3 O 4 nanoparticles, exhibiting larger specific surface area than rGO. Due to the low toxicity and magnetism of Fe 3 O 4 , FrGO owned more favorable biocompatibility and the application of magnetic-separation simplified the preparation procedure. After hybridizing with Au NPs, FrGO exhibited more excellent electrical conductivity and could immobilize more CeO 2 @TiO 2 and antibodies. Therefore, a novel label-free ECL immunosensor based on Au-FrGO-CeO 2 @TiO 2 was constructed which generated higher ECL response. To investigate the performance of the immunosensor, carcinoembryonic antigen (CEA) was chosen as a model target analyte. Under optimal conditions, the immunosensor had sensitive response to CEA in a wide linear range of 0.01pgmL -1 to 10ngmL -1 with a detection limit of 3.28 fg mL -1 . The proposed ECL immunosensor exhibited excellent stability, repeatability and selectivity, which opened another promising avenue for CEA determination in real serum samples., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The CeO 2 @TiO 2 core-shell nanostructure catalyst prepared by a two-step hydrothermal method was used for selective catalytic reduction (SCR) of NOx with NH 3 in this study. The catalyst presented the obvious core-shell structure, and the shell was amorphous TiO 2 which could protect the active center from the SO 2 erosion. The catalyst showed high activity and stability, excellent N 2 selectivity and superior SO 2 resistance and H 2 O tolerance. Characterizations such as TEM, HR-TEM, XRD, BET, XPS, NH 3 -TPD, and H 2 -TPR were carried out. The results indicated that the catalyst had large surface area and the active sites were well dispersed on the surface. The NH 3 -TPD, H 2 -TPR and XPS results implied that its increased SCR activity might be due to the enhancement of NH 3 chemisorption and the increase of active oxygen species, both of which were conductive to NH 3 activation. The excellent catalytic performance suggests that it is a promising candidate for SCR catalyst., (Copyright © 2016. Published by Elsevier B.V.)

Magnetic cerium-doped mesoporous titanium dioxide was synthesized by combining sol-gel method and calcination using tetrabutanate and ammonium cerium nitrate as precursors and Pluronic P123 as a template coating on iron oxide covered with carbon in ethanol. The magnetic Ce-doped catalyst showed only anatase structure with a slight increase in lattice parameters compared to the undoped catalyst. The Ce L III -edge X-ray absorption near-edge spectroscopy (XANES) spectra showed Ce 3+ , and the cerium substitution doping into titanium dioxide was proposed. Degradation of S-metolachlor in aqueous magnetic photocatalyst suspension followed (pseudo) first-order kinetics in the presence of 0.5 g L -1 of γ-Fe 2 O 3 @C@0.16 mol% Ce-mTiO 2 with a half-life of 55.18 ± 1.63 min. Fifteen degradation products were identified, and their transformation routes of the photocatalytic degradation were then proposed. Complementary toxicity assessment of the treated S-metolachlor solution was undertaken with Environment Canada's algal microplate assay measuring growth inhibition (72-h IC 50 ) in the freshwater chlorophyte Pseudokirchneriella subcapitata. This test method revealed a significant decrease in toxicity (1.7-fold reduction after 180 min of irradiation treatment), thereby confirming that the by-products formed following photocatalysis would be less harmful from an environmental point of view. Photocatalytic degradation of S-metolachlor thus appears to hold promise as a cost-effective treatment technology to diminish the presence of this herbicide in aquatic systems.

The leading edge of catalysis research motivates physical understanding of the growth of nanoscale oxide structures on different supporting oxide materials that are themselves also nanostructured. This research opens up for consideration a diverse range of facets on the support material, versus the single facet typically involved in wide-area growth of thin films. Here, we study the growth of ceria nanoarchitectures on practical anatase titania powders as a showcase inspired by recent experiments. Density functional theory (DFT)-based methods are employed to characterize and rationalize the broad array of low energy nanostructures that emerge. Using a bottom-up approach, we are able to identify and characterize the underlying mechanisms for the facet-dependent growth of various ceria motifs on anatase titania based on formation energy. These motifs include 0D clusters, 1D chains, 2D plates, and 3D nanoparticles. The ceria growth mode and morphology are determined by the interplay of several factors including the role of the common cation valence, the interface template effect for different facets of the anatase support, enhanced ionic binding for more compact ceria motifs, and the local structural flexibility of oxygen ions in bridging the interface between anatase and ceria structures.

Changes in tissue transcriptomes and productivity of Arabidopsis thaliana were investigated during exposure of plants to 2 widely used engineered metal oxide nanoparticles, titanium dioxide (nano-titania) and cerium dioxide (nano-ceria). Microarray analyses confirmed that exposure to either nanoparticle altered the transcriptomes of rosette leaves and roots, with comparatively larger numbers of differentially expressed genes found under nano-titania exposure. Nano-titania induced more differentially expressed genes in rosette leaves, whereas roots had more differentially expressed genes under nano-ceria exposure. MapMan analyses indicated that although nano-titania up-regulated overall metabolism in both tissues, metabolic processes under nano-ceria remained mostly unchanged. Gene enrichment analysis indicated that both nanoparticles mainly enriched ontology groups such as responses to stress (abiotic and biotic), and defense responses (pathogens), and responses to endogenous stimuli (hormones). Nano-titania specifically induced genes associated with photosynthesis, whereas nano-ceria induced expression of genes related to activating transcription factors, most notably those belonging to the ethylene responsive element binding protein family. Interestingly, there were also increased numbers of rosette leaves and plant biomass under nano-ceria exposure, but not under nano-titania. Other transcriptomic responses did not clearly relate to responses observed at the organism level, possibly because of functional and genomic redundancy in Arabidopsis, which may mask expression of morphological changes, despite discernable responses at the transcriptome level. In addition, transcriptomic changes often relate to transgenerational phenotypic development, and hence it may be productive to direct further experimental work to integrate high-throughput genomic results with longer term changes in subsequent generations. Environ Toxicol Chem 2017;36:71-82. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America., (Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.)

Tetrabromobisphenol A, one of the most important brominated retardants, is an typical persistent organic pollutant and it is of great value to develop rapid and effective degradation method. Present study established a photoelectrodegradation method with CeO 2 and reduced graphene oxide co-modified TiO 2 nanotube arrays (RGO-CeO 2 -TiO 2 NAs), which were successfully synthesized and characterized with scanning electron microscopy (SEM) and Energy Dispersive X Ray Spectrometry (EDX). The SEM Images revealed that the nanotubes had a diameter of about 100 nm and an obvious layer of CeO 2 and RGO on the surface of TiO 2 nanotube arrays. The EDX data exhibited the presence of Ce element. The results demonstrated that TBBPA was degraded at a high degradation rate constant of 0.0191 min -1 , and photogenerated holes played a major role in the degradation reaction. Significant decrease of degradation efficiency was achieved with the presence of EDTA-2Na(hole scavenger), yet while the existence of t-BuOH(OH scavenger) resulted in less inhibition on the degradation. Besides, RGO-CeO 2 -TiO 2 NAs exhibited good stability with rarely decline of degradation efficiency for ten reused runs. All these indicated that RGO-CeO 2 -TiO 2 NAs were a good catalyst with extraordinary catalytic activity and stability for PEC degradation, and would have great potential in the control and removal of pollutants., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

To photo-catalytically degrade RhB dye using solar irradiation, CeO 2 doped TiO 2 nanocomposites were synthesized hydrothermally at 700 °C for 9 hrs. All emission spectra showed a prominent band centered at 442 nm that was attributed to oxygen related defects in the CeO 2 -TiO 2 nanocrystals. Two sharp absorption bands at 1418 cm -1 and 3323 cm -1 were attributed to the deformation and stretching vibration, and bending vibration of the OH group of water physisorbed to TiO 2 , respectively. The photocatalytic activities of Ce-TiO 2 nanocrystals were investigated through the degradation of RhB under UV and UV+ visible light over a period of 8 hrs. After 8 hrs, the most intense absorption peak at 579 nm disappeared under the highest photocatalytic activity and 99.89% of RhB degraded under solar irradiation. Visible light-activated TiO 2 could be prepared from metal-ion incorporation, reduction of TiO 2 , non-metal doping or sensitizing of TiO 2 using dyes. Studying the antibacterial activity of Ce-TiO 2 nanocrystals against E. coli revealed significant activity when 10 μg was used, suggesting that it can be used as an antibacterial agent. Its effectiveness is likely related to its strong oxidation activity and superhydrophilicity. This study also discusses the mechanism of heterogeneous photocatalysis in the presence of TiO 2 .

A series of MnO x -CeO₂ and MnO x -TiO₂ catalysts were prepared by a homogeneous precipitation method and their catalytic activities for the NO oxidation in the absence or presence of SO₂ were evaluated. Results show that the optimal molar ratio of Mn/Ce and Mn/Ti are 0.7 and 0.5, respectively. The MnO x -CeO₂ catalyst exhibits higher catalytic activity and better resistance to SO₂ poisoning than the MnO x -TiO₂ catalyst. On the basis of Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and scanning transmission electron microscope with mapping (STEM-mapping) analyses, it is seen that the MnO x -CeO₂ catalyst possesses higher BET surface area and better dispersion of MnO x over the catalyst than MnO x -TiO₂ catalyst. X-ray photoelectron spectroscopy (XPS) measurements reveal that MnO x -CeO₂ catalyst provides the abundance of Mn 3+ and more surface adsorbed oxygen, and SO₂ might be preferentially adsorbed to the surface of CeO₂ to form sulfate species, which provides a protection of MnO x active sites from being poisoned. In contrast, MnO x active sites over the MnO x -TiO₂ catalyst are easily and quickly sulfated, leading to rapid deactivation of the catalyst for NO oxidation. Furthermore, temperature programmed desorption with NO and O₂ (NO + O₂-TPD) and in situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS) characterizations results show that the MnO x -CeO₂ catalyst displays much stronger ability to adsorb NO x than the MnO x -TiO₂ catalyst, especially after SO₂ poisoning.

The increasing use of engineered nanoparticles (NPs) in a wide range of commercial products raises concern about the possible risks that NPs pose to human health. Many aspects of the interaction between living cells and NPs are still unclear, and a reliable assessment of NP genotoxicity would be important. One of the most common tests used for genotoxicity is the comet assay, a sensitive method measuring DNA damage in individual cells. The assay was originally developed for soluble molecules, but it is also used in the assessment of genotoxicity of NPs. However, concerns have been raised recently about the reliability of this test in the case of NPs, but no conclusive results have been presented. Using nuclei isolated from human epithelial cells incubated with NPs, we obtained clear evidence of overestimation of NP genotoxicity by the comet assay in the case of CeO2, TiO2, SiO2, and polystyrene NPs. Removal of the NPs in the cytoplasm was effective in eliminating this genotoxicity overestimation (ex post damage) and determining the actual damage produced by the NPs during incubation with the cells (ex ante damage). This method could improve significantly the determination of NP genotoxicity in eukaryotic cells.

Ten agronomic plant species were exposed to different concentrations of nano-titanium dioxide (nTiO2 ) or nano-cerium oxide (nCeO2 ) (0 μg/mL, 250 μg/mL, 500 μg/mL, and 1000 μg/mL) to examine potential effects on germination and early seedling development. The authors modified a standard test protocol developed for soluble chemicals (OPPTS 850.4200) to determine if such an approach might be useful for screening engineered nanomaterials (ENMs) and whether there were differences in response across a range of commercially important plant species to 2 common metal oxide ENMs. Eight of 10 species responded to nTiO2 , and 5 species responded to nCeO2 . Overall, it appeared that early root growth may be a more sensitive indicator of potential effects from ENM exposure than germination. The observed effects did not always relate to the exposure concentration, indicating that mass-based concentration may not fully explain the developmental effects of these 2 ENMs. The results suggest that nTiO2 and nCeO2 have different effects on early plant growth of agronomic species, with unknown effects at later stages of the life cycle. In addition, standard germination tests, which are commonly used for toxicity screening of new materials, may not detect the subtle but potentially more important changes associated with early growth and development in terrestrial plants. Environ Toxicol Chem 2016;35:2223-2229. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America., (Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America.)

Catalytic destruction of PCDD/Fs (polychlorinated dibenzo-p-dioxins and furans) over V2O5-CeO2/TiO2 catalyst was investigated at a low temperature range of 140-180 °C, in the absence and presence of ozone (200 ppm). Nano-TiO2 support was used to prepare the catalyst by step impregnation method. A stable PCDD/Fs-generating system was established to support the catalytic destruction tests. In the presence of ozone alone, destruction efficiencies of PCDD/Fs are between 32.2 and 43.1 % with temperature increasing from 140 to 180 °C. The activity of V2O5-CeO2/TiO2 catalyst alone on PCDD/Fs destruction is also studied. The increase of temperature from 140 to 180 °C enhances the activity of catalyst with destruction efficiencies increasing from 54.7 to 73.4 %. However, ozone addition greatly enhances the catalytic activity of V2O5-CeO2/TiO2 catalyst on PCDD/Fs decomposition. At 180 °C, the destruction efficiency of PCDD/Fs achieved with V2O5-CeO2/TiO2 catalyst and ozone is above 86.0 %. It indicates that the combined use of ozone and catalyst reduces the reaction temperature of PCDD/Fs oxidation and offers a new method to destroy PCDD/Fs with high destruction efficiency at a low temperature. Furthermore, the destruction efficiencies of 17 toxic PCDD/F congeners, achieved with ozone alone, catalyst alone, and catalyst/ozone are analyzed.

The photocatalytic film Ce doped VxOy/TiO2 was loaded on cordierite honeycomb (CHC), and this composite was prepared by sol-gel and dipping method, with Ce, oxides of V and TiO2 as dopant and key substances, respectively. Using gaseous 1,2-dichlorobenzene to replace dioxin as target pollutant, dual degradation experiments at 140-280 °C were carried out (thermal decomposition and photodegradation), and the effects of preparation conditions on catalytic activity were investigated: doping amount of Ce, dipping time in the gel, the concentration of ammonium metavanadate (NH4VO3) solution, dipping time in NH4VO3 solution, sintering temperature. The gaseous samples were taken before and after the reactor and analyzed by gas chromatography. According to the results, the optimal preparation conditions were determined, and the corresponding removal rate was above 95% after 90 min of degradation at 280 °C. The composite was examined by ultrasonic to analyze the adhesive strength between the film and CHC, and further characterized by XRD and SEM. Furthermore, flue gas from waste incinerator was chosen as target pollutant, which contained PCDD/Fs, the industrial sidestream degradation experiment was carried out and showed excellent removal efficiency of the composite, the removal rate of PCDD/Fs reached ca. 90% after 90 min of degradation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Nanoparticles are produced and used worldwide and are released to the environment, e.g., into soil systems. Titanium dioxide (TiO2) nanoparticles (NPs), carbon nanotubes (CNTs) and cerium dioxide (CeO2) NPs are among the ten most produced NPs and it is therefore important to test, whether these NPs affect plants and symbiotic microorganisms that help plants to acquire nutrients. In this part of a joint companion study, we spiked an agricultural soil with TiO2 NPs, multi walled CNTs (MWCNTs), and CeO2 NPs and we examined effects of these NP on red clover, biological nitrogen fixation by rhizobia and on root colonization of arbuscular mycorrhizal fungi (AMF). We also tested whether effects depended on the concentrations of the applied NPs., Results: Plant biomass and AMF root colonization were not negatively affected by NP exposure. The number of flowers was statistically lower in pots treated with 3 mg kg(-1) MWCNT, and nitrogen fixation slightly increased at 3000 mg kg(-1) MWCNT., Conclusions: This study revealed that red clover was more sensitive to MWCNTs than TiO2 and CeO2 NPs. Further studies are necessary for finding general patterns and investigating mechanisms behind the effects of NPs on plants and plant symbionts.

In this study, magnetic graphene oxide-loaded Ce-doped titania (MGO-Ce-TiO2) hybridized composite was prepared by a facile method. The as-prepared samples exhibited good adsorption capacity, high visible-light photoactive and magnetic separability as a novel photocatalyst in the degradation of tetracyclines (TC). The intermediate products and photocatalytic route of TC were proposed based on the analysis results of LC-MS. Moreover, the repeatability of the photoactivity with the use of MGO-Ce-TiO2 was investigated in the multi-round experiments with the assistance of an applied magnetic field. Therefore, the prepared composite photocatalysts were considered as a kind of promising photocatalyst in a suspension reaction system, in which they can offer effectively recovery ability. The effect of MGO content on the photocatalytic performance was also studied, and an optimum content was obtained., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In order to reduce the costs, the recycle of spent TiO2-based SCR-DeNOx catalysts were employed as a potential catalytic support material for elemental mercury (Hg(0)) oxidation in simulated coal-fired flue gas. The catalytic mechanism for simultaneous removal of Hg(0) and NO was also investigated. The catalysts were characterized by Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) method. Results indicated that spent TiO2-based SCR-DeNOx catalyst supported Ce-Mn mixed oxides catalyst (CeMn/SCR1) was highly active for Hg(0) oxidation at low temperatures. The Ce1.00Mn/SCR1 performed the best catalytic activities, and approximately 92.80% mercury oxidation efficiency was obtained at 150 °C. The inhibition effect of NH3 on Hg(0) oxidation was confirmed in that NH3 consumed the surface oxygen. Moreover, H2O inhibited Hg(0) oxidation while SO2 had a promotional effect with the aid of O2. The XPS results illustrated that the surface oxygen was responsible for Hg(0) oxidation and NO conversion. Besides, the Hg(0) oxidation and NO conversion were thought to be aided by synergistic effect between the manganese and cerium oxides.