Psoriasis is an inflammatory skin disease that is intricately linked to oxidative stress.Antioxidation and inhibition of abnormal proliferation of keratinocytes are pivotal strategies for psoriasis.Delivering drugs wi...Psoriasis is an inflammatory skin disease that is intricately linked to oxidative stress.Antioxidation and inhibition of abnormal proliferation of keratinocytes are pivotal strategies for psoriasis.Delivering drugs with these effects to the site of skin lesions is a challenge that needs to be solved.Herein,we reported a nanotransdermal delivery system composed of all-trans retinoic acid(TRA),triphenylphosphine(TPP)-modified cerium oxide(CeO2)nanoparticles,flexible nanoliposomes and gels(TCeO_(2)-TRA-FNL-Gel).The results revealed that TCeO_(2)synthesized by the anti-micelle method,with a size of approximately 5 nm,possessed excellent mitochondrial targeting ability and valence conversion capability related to scavenging reactive oxygen species(ROS).TCeO_(2)-TRA-FNL prepared by the film dispersion method,with a size of approximately 70 nm,showed high drug encapsulation efficiency(>96%).TCeO_(2)-TRA-FNL-Gel further showed sustained drug release behaviors,great transdermal permeation ability,and greater skin retention than the free TRA.The results of in vitro EGF-induced and H2O2-induced models suggested that TCeO_(2)-TRA-FNL effectively reduced the level of inflammation and alleviated oxidative stress in HaCat cells.The results of in vivo imiquimod(IMQ)-induced model indicated that TCeO_(2)-TRA-FNL-Gel could greatly alleviate the psoriasis symptoms.In summary,the transdermal drug delivery system designed in this study has shown excellent therapeutic effects on psoriasis and is prospective for the safe and accurate therapy of psoriasis.展开更多
The present study aims at the numerical simulations of the melting process of cerium oxide particles in RF thermal plasma.The physical model and the calculating method were described firstly;the interaction between ce...The present study aims at the numerical simulations of the melting process of cerium oxide particles in RF thermal plasma.The physical model and the calculating method were described firstly;the interaction between cerium oxide particles and plasma was analyzed;specific attention was given to the effects of particle initial size,injection velocity on the particle melting and trajectory in plasma.The influence of the temperature field and velocity field distribution of the plasma around the particle trajectory on the melting effect is analyzed,and the relationship between the heat absorption efficiency of the particles and the particle size reduction process is further determined.It is also found that there exists an optimal particle initial injection velocity which led to a more concentrated final particle size distribution and a more significant reduction of particle size.The results could provide effective guidance for understanding the plasma spheroidization process of uranium dioxide and cerium dioxide powder particles.展开更多
Oxaliplatin is a chemotherapeutic drug used for colorectal cancer treatment. The testicular toxic effect is one of its recorded toxicities which resulted in a few studies. Oxidative stress could be a direct cause of t...Oxaliplatin is a chemotherapeutic drug used for colorectal cancer treatment. The testicular toxic effect is one of its recorded toxicities which resulted in a few studies. Oxidative stress could be a direct cause of this testicular toxicity. Cerium oxide nanoparticles (CONPs) are optimistic antioxidants for applications in medicine. The aim of the work is to study the protective effect of CONPs on testicular toxicity induced by oxaliplatin in rats. Forty adult male albino rats were divided into 4 groups: Control group, CONPs group (60 mg/kg, 5 times/week), Oxaliplatin group (4 mg/kg, twice/week), and Oxaliplatin & CONPs group, for 4 weeks. Seventy-two hours after the last administration, blood samples were taken for hormonal levels and testes were used for both histopathology and immunohistochemical microscopic examination. Sperm smears were also performed and their results were statistically analyzed to detect any sperm abnormalities. Oxaliplatin increased MDA levels. SOD and GPx activity was decreased. GSH levels were decreased. Also, it decreased the sperm cell count and serum testosterone, and anti-Müllerian hormon. In the testicular sections, significant histopathology changes were seen and immunohistochemical examination confirmed these results. Upon supplementation of CONPs with oxaliplatin decreased MDA levels. SOD and GPx activity was increased, and GSH did not change. In testicular sections, normal morphology was seen. Also, there was an increase in the sperm cell count and serum testosterone anti-Müllerian with significant improvement of testicular architecture, and immunohistochemical examination confirmed these results. The utilization of CONPs produced significant protection against all of the above-mentioned changes.展开更多
Cerium oxide nanoparticles(CNPs)possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences+3 and+4.This article reviews recent articles dealing...Cerium oxide nanoparticles(CNPs)possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences+3 and+4.This article reviews recent articles dealing with in vivo studies of CNPs towards Alzheimer’s disease,obesity,liver inflammation,cancer,sepsis,amyotrophic lateral sclerosis,acute kidney injury,radiation-induced tissue damage,hepatic ischemia reperfusion injury,retinal diseases and constipation.In vivo anti-cancer studies revealed the effectiveness of CNPs to reduce tumor growth and angiogenesis in melanoma,ovarian,breast and retinoblastoma cancer cell-induced mice,with their conjugation with folic acid,doxorubicin,CPM,or CXC receptor-4 antagonist ligand eliciting higher efficiency.After conjugation with triphenylphosphonium or magnetite nanoparticles,CNPs were shown to combat Alzheimer’s disease by reducing amyloid-β,glial fibrillary acidic protein,inflammatory and oxidative stress markers in mice.By improving muscle function and longevity,the citrate/EDTA-stabilized CNPs could ameliorate amyotrophic lateral sclerosis.Also,they could effectively reduce obesity in mice by scavenging ROS and reducing adipogenesis,triglyceride synthesis,GAPDH enzyme activity,leptin and insulin levels.In CCl4-induced rats,stress signaling pathways due to inflammatory cytokines,liver enzymes,oxidative and endoplasmic reticulum messengers could be attenuated by CNPs.Commercial CNPs showed protective effects on rats with hepatic ischemia reperfusion and peritonitis-induced hepatic/cardiac injuries by decreasing oxidative stress and hepatic/cardiac inflammation.The same CNPs could improve kidney function by diminishing renal superoxide,hyperglycemia and tubular damage in peritonitis-induced acute kidney injury in rats.Radiation-induced lung and testicular tissue damage could be alleviated in mice,with the former showing improvement in pulmonary distress and bronchoconstriction and the latter exhibiting restoration in spermatogenesis rate and spermatid/spermatocyte number.Through enhancement of gastrointestinal motility,the CNPs could alleviate constipation in both young and old rats.They could also protect rat from light-induced retinal damage by slowing down neurodegenerative process and microglial activation.展开更多
CeO2 nanometer powders of different sizes were prepared at low temperature by pyrolysis of amorphous citrate. XRD patterns show that CeO2 is cubic in structure, space group Oh5-FM3M·TEM indicates that the prepare...CeO2 nanometer powders of different sizes were prepared at low temperature by pyrolysis of amorphous citrate. XRD patterns show that CeO2 is cubic in structure, space group Oh5-FM3M·TEM indicates that the prepared CeO2 is spherical in shape, and the particle size distribution is in narrow range. It was found that calcination temperature is a more important factor affecting the crystallite size of CeO2 than calcining time, the smaller the particle. the bigger the crystallattice distortion, the worse the crystal growth. Solubility test of CeO2 in nitric acid reveals that the surface activity of CeO2 decreases with the increasing particle sizes. IR spectra analysis shows that the absorption of Ce-O bond is shifted to higher energy with the decrease of CeO2 particle sizes.展开更多
Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt back- ground and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The...Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt back- ground and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The cathodic reaction mechanism of the molten salt background was: O2+e - O2-2;O2+2NO-3→2NO-2+2O02. According to the results of SEM and XPS, cerium oxide film, which is composed of CeO2, can form on the nickel electrode at - 1.850 V vs. Ag/ AgNO3(0.1mol/L) reference electrode.展开更多
Glasses and glass ceramics in the system xCeO<sub>2·</sub>(50 - x)PbO·50B<sub>2</sub>O<sub>3</sub> (0 ≤ x ≤ 50) have been studied, for the first time, by NMR a...Glasses and glass ceramics in the system xCeO<sub>2·</sub>(50 - x)PbO·50B<sub>2</sub>O<sub>3</sub> (0 ≤ x ≤ 50) have been studied, for the first time, by NMR and FTIR techniques. Effect of CeO<sub>2</sub> substitution with PbO on NMR parameters has been discussed in terms of changing both boron and cerium coordination. The quantitative fraction of four coordinated boron (N<sub>4</sub>) has been simply determined from <sup>11</sup>B NMR spectroscopy. On the other hand, the fraction of total tetrahedral structural units B<sub>4</sub> (BO<sub>4</sub> + PbO<sub>4</sub> + CeO<sub>4</sub>) is obtained from FTIR spectral analysis. It is not possible to get the fraction of cerium oxide directly from the applied spectroscopic tools. Therefore, a simple approach is applied, for the first time, to determine CeO<sub>4</sub> fraction by using the different criteria of both <sup>11</sup>B NMR and FTIR spectroscopy. The fraction of B<sub>4</sub> species is equal to N<sub>4</sub>, within the experimental error, of the same glasses in the composition region of up to 10 mol% CeO<sub>2</sub>. On the other hand, there is a clear difference between both N<sub>4</sub> and B<sub>4</sub> values in glasses of higher CeO<sub>2 </sub>content (>10 mol%). The related difference showed a linear increasing trend with increasing the content of CeO<sub>2</sub> in the glass. This was discussed on the bases of structural role of CeO<sub>2</sub> which acts as a glass former in the region >10 mol%, while, at lower concentration, it consumed as a glass modifier.展开更多
Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH pr...Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structural,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction(XRD),a UV-vis spectrometer,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy(EDAX),Raman spectroscopy and X-ray photo electron spectroscopy(XPS).According to the findings,hydrothermally synthesized cerium oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environmental water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the water in simple way and degradation is the one of the methods to purify salt water.展开更多
Co-precipitation was used to prepare cerium oxide nano-particles. The effects of aging temperature and concentration of cobalt ion on the optical property, morphology, and particle size were investigated. The cerium o...Co-precipitation was used to prepare cerium oxide nano-particles. The effects of aging temperature and concentration of cobalt ion on the optical property, morphology, and particle size were investigated. The cerium oxide was prepared by adding ammonia solution into a mixed solution of cerium nitrate with cobalt nitrate solutions to obtain a large amount of precipitates and then aged further. Subsequently, the precipitates were kept in an oven for calcination keeping the temperature at 400?C for lasting 24 h. The average size of cerium oxide particles was obtained from the (111) peak in the X-ray diffraction pattern using the Scherrer equation. The crystal sizes obtained were found to be in the range of 11.82 - 13.47 nm. The results showed that the particle size decreased with an increase in the Co ion concentration and decreased with an increase in temperature. The SEM pictures show that the morphology for cerium oxide is granular and/or columnar. It can be seen from UV/Vis absorption spectrum that the maximum absorption peaks were in the range of 334 - 390 nm, depending on the operating conditions. The corresponding energy gaps were observed in the range of 3.18 - 3.71 eV. Subsequently, the Brus equation for the energy gap was discussed. Finally, particle size was correlated with the aging temperature and Co ion concentration.展开更多
Nanotechnology deals with particles ranging from 1 to 100 nm in size called as nanoparticles.These nano particles exhibit unique properties which find an application in many industries and medical fields.A growing bod...Nanotechnology deals with particles ranging from 1 to 100 nm in size called as nanoparticles.These nano particles exhibit unique properties which find an application in many industries and medical fields.A growing body of evidence points out the newer developing technologies adopted in the field of medicine in terms of target therapies,imaging systems,drug deliveries,etc.is through the incorporation of nanoparticles.Cerium oxide nanoparticles have gained attention in the last decade due to exceptional properties such as redox activity,biofilm inhibition,antibacterial activity,anti-inflammatory activity,etc.The method of synthesis of cerium oxide nanoparticles plays a pivotal role in its application.It exhibits redox properties and catalytic activity and thus has found its use in biomedical applications.Nanoparticles are incorporated into dental materials such as restorative cements/sealants,adhesives,and denture systems to improve their properties.Among the various metal oxide nanoparticles,ce rium oxide nanoparticles(CeO_(2)NPs)are known to exhibit lower toxicity to mammalian cells and possess unique antibacterial mechanism.In addition,they exhibit potent properties such as antitumor,antiinflammatory,antibacterial activities,and functions as an immunosensor.CeO_(2)NPs have excellent scavenging properties for reactive oxygen species,which is why they are being considered for therapeutic purposes.In this review,various methods of synthesis of CeO_(2)NPs are discussed.Several factors that determine the particle size and morphology of these materials are important for biomedical and dental applications.Emphasis is given to preparation methods and variables such as calcination temperature,which have a profound effect on particle size and morphology.This article also presents various applications of CeO_(2)NPs in the biomedical and dental fields.展开更多
The disability,mortality and costs due to ionizing radiation(IR)-induced osteoporotic bone fractures are sub-stantial and no effective therapy exists.Ionizing radiation increases cellular oxidative damage,causing an i...The disability,mortality and costs due to ionizing radiation(IR)-induced osteoporotic bone fractures are sub-stantial and no effective therapy exists.Ionizing radiation increases cellular oxidative damage,causing an imbalance in bone turnover that is primarily driven via heightened activity of the bone-resorbing osteoclast.We demonstrate that rats exposed to sublethal levels of IR develop fragile,osteoporotic bone.At reactive surface sites,cerium ions have the ability to easily undergo redox cycling:drastically adjusting their electronic con-figurations and versatile catalytic activities.These properties make cerium oxide nanomaterials fascinating.We show that an engineered artificial nanozyme composed of cerium oxide,and designed to possess a higher fraction of trivalent(Ce^(3+))surface sites,mitigates the IR-induced loss in bone area,bone architecture,and strength.These investigations also demonstrate that our nanozyme furnishes several mechanistic avenues of protection and selectively targets highly damaging reactive oxygen species,protecting the rats against IR-induced DNA damage,cellular senescence,and elevated osteoclastic activity in vitro and in vivo.Further,we reveal that our nanozyme is a previously unreported key regulator of osteoclast formation derived from macrophages while also directly targeting bone progenitor cells,favoring new bone formation despite its exposure to harmful levels of IR in vitro.These findings open a new approach for the specific prevention of IR-induced bone loss using synthesis-mediated designer multifunctional nanomaterials.展开更多
Respiratory syncytial virus(RSV)is the most common cause of viral bronchiolitis among children worldwide,yet there is no vaccine for RSV disease.This study investigates the potential of cube and sphere-shaped cerium o...Respiratory syncytial virus(RSV)is the most common cause of viral bronchiolitis among children worldwide,yet there is no vaccine for RSV disease.This study investigates the potential of cube and sphere-shaped cerium oxide nanoparticles(CNP)to modulate reactive oxygen(ROS)and nitrogen(RNS)species and immune cell phenotypes in the presence of RSV infection in vitro and in vivo.Cube and sphere-shaped CNP were synthesized by hydrothermal and ultrasonication methods,respectively.Physico-chemical characterization confirmed the shape of sphere and cube CNP and effect of various parameters on their particle size distribution and zeta potential.In vitro results revealed that sphere and cube CNP differentially modulated ROS and RNS levels in J774 macrophages.Specifically,cube CNP significantly reduced RSV-induced ROS levels without affecting RNS levels while sphere CNP increased RSV-induced RNS levels with minimal effect on ROS levels.Cube CNP drove an M1 phenotype in RSV-infected macrophages in vitro by increasing macrophage surface expression of CD80 and CD86 with a concomitant increase in TNFαand IL-12p70,while simultaneously decreasing M2 CD206 expression.Intranasal administration of sphere and cube-CNP were well-tolerated with no observed toxicity in BALB/c mice.Notably,cube CNP preferentially accumulated in murine alveolar macrophages and induced their activation,avoiding enhanced uptake and activation of other inflammatory cells such as neutrophils,which are associated with RSV-mediated inflammation.In conclusion,we report that sphere and cube CNP modulate macrophage polarization and innate cellular responses during RSV infection.展开更多
Ultrafine rare-earth oxides(REOs) are widely applied in all fields of daily life,but the conventional preparation methods are limited by a long procedure,low efficiency and severe environmental pollution.Our team has ...Ultrafine rare-earth oxides(REOs) are widely applied in all fields of daily life,but the conventional preparation methods are limited by a long procedure,low efficiency and severe environmental pollution.Our team has independently developed a jet pyrolysis reactor for the preparation of ultrafine cerium oxides,and this process has theoretical significance and practical application values.In this study,gas-solid pyrolysis reactions inside the jet-flow pyrolysis reactor were numerically simulated.We performed a coupling computation of the combustion,phase transformation and gas-solid reaction on Fluent and userdefined functions.We characterized the flows of different phases as well as the compositions and distributive laws of the reactants/products in the reactor.The gas-phase inlet velocity and dynamic pressure/additional pressure were related by a quadratic function.The velocity at the throat inlet changed the most,and the outlet velocity was very stable.The CeO2 concentrations were obviously stratified.This study enriches theories of jet-flow pyrolysis and theoretically underlies the optimization and popularization of self-developed pyrolysis reactors.展开更多
A novel arsenic adsorbent with hydrous cerium oxides coated on glass fiber cloth(HCO/GFC)was synthesized.The HCO/GFC adsorbents were rolled into a cartridge for arsenic removal test.Due to the large pores between the ...A novel arsenic adsorbent with hydrous cerium oxides coated on glass fiber cloth(HCO/GFC)was synthesized.The HCO/GFC adsorbents were rolled into a cartridge for arsenic removal test.Due to the large pores between the glass fibers,the arsenic polluted water can flow through easily.The arsenic removal performance was evaluated by testing the equilibrium adsorption isotherm,adsorption kinetics,and packed-bed operation.The pH effects on arsenic removal were conducted.The test results show that HCO/GFC filter has high As(Ⅴ)and As(Ⅲ)removal capacity even at low equilibrium concentration.The more toxic As(Ⅲ)in water can be easily removed within a wide range of solution p H without pre-treatment.Arsenic contaminated ground-water from Yangzong Lake(China)was used in the column test.At typical breakthrough conditions(the empty bed contact time,EBCT=2 min),arsenic researched breakthrough at over 24,000 bed volumes(World Health Organization(WHO)suggested that the maximum contaminant level(MCL)for arsenic in drinking water is 10 mg/L).The Ce content in the treated water was lower than 5 ppb during the column test,which showed that cerium did not leach from the HCO/GFC material into the treated water.The relationship between dosage of adsorbents and the adsorption kinetic model was also clarified,which suggested that the pseudo second order model could fit the kinetic experimental data better when the adsorbent loading was relatively low,and the pseudo first order model could fit the kinetic experimental data better when the adsorbent loading amount was relatively high.展开更多
Inadequate angiogenesis is a hallmark of conditions including cardiovascular diseases,stroke and chronic diabetic wounds,which exhibit tissue ischaemia ensuring that therapeutic strategies to promote angiogenesis are ...Inadequate angiogenesis is a hallmark of conditions including cardiovascular diseases,stroke and chronic diabetic wounds,which exhibit tissue ischaemia ensuring that therapeutic strategies to promote angiogenesis are of great interest.However,many angiogenic treatments involve the delivery of growth factors which have limited clinical success due to poor stability,high manufacturing cost and poor efficacy.Cerium oxide nanoparticles(nanoceria)can either promote or inhibit angiogenesis depending on their surface corona chemistry.Here,nanoceria were functionalized with an intentional heparin corona,a polysaccharide which binds and signals growth factors,of different chain lengths and surface grafting density to establish their effect on angiogenesis.These nanoparticles promoted angiogenesis in vivo with the surface grafting density positively correlated with angiogenesis over the widest concentration range;however,chain length did not play a role.The heparin–nanoceria supported fibroblast growth factor 2(FGF2)signalling in vitro and promoted FGF2-mediated angiogenesis in vivo.The nanoparticles were internalized by endothelial cells in vitro where they trafficked to the lysosomes and reduced cell viability suggesting that the angiogenic activity of heparin–nanoceria is mediated in the extracellular environment.Together,this study adds to our knowledge of the angiogenic effects of heparin–nanoceria towards finding new angiogenic treatments.展开更多
In general, inorganic filler/polyurethane elastomer(PUE) composites possess favorable properties, such as modulus, chemical resistance, and heat stability, are promising for broadening the application area of polyuret...In general, inorganic filler/polyurethane elastomer(PUE) composites possess favorable properties, such as modulus, chemical resistance, and heat stability, are promising for broadening the application area of polyurethanes(PU). For the experiments, a series of cerium oxide(CeO_(2))/PUE composites were prepared with different sizes and appearance of CeO_(2), and different mixing methods as well. CeO_(2) particles with different sizes were added into PUs during the formation of urethane linkage and the chain-extend process, respectively. The morphology along with mechanical properties, thermal properties of the composites were studied. The results suggest that the size of CeO_(2) and mixing methods influence the microstructure of PUs which has profound effect on properties of these composites. The composites tend to form more quantity of hard domains(HDs) with small size when CeO_(2) particles were added before the formation of urethane linkage, whereas Ce O2 particles increase the size of HDs when added with chain extender into PU prepolymer.展开更多
Cerium oxide possesses intrinsic hydrophobic properties ascribed to the unique electronic structure.However,the relationship between the crystal structure and hydrophobicity of cerium oxide has not been systematically...Cerium oxide possesses intrinsic hydrophobic properties ascribed to the unique electronic structure.However,the relationship between the crystal structure and hydrophobicity of cerium oxide has not been systematically studied.Herein,it is experimentally and theoretically demonstrated that the water contact angle(105.9°)of the(111)surface is higher than that(91.7°)of the(220)surface,associated with the lower surface free energy(28.44 mN/m)of(111)surface than that(38.48 mN/m)of(220)surface.Furthermore,cerium oxide films with(111)-terminated surface are annealed at 300℃ and 600℃ for1 h,respectively.The lattice constant increases(5.4594Å<5.4613Å<5.4670Å)with decreasing the annealing temperature(600℃>300℃>the as-deposited),leading to the increased water contact angle(96.7°<96.8°<99.0°).The First-principles calculation provides microscopic insights into the wetting mechanism,originating from the weakened adsorption capacity of the(111)surface for water molecules with the increasing lattice constant.展开更多
Dry eye disease(DED)is the most common eye disease in ophthalmic consultation except for refractive errors.Therefore,an exploration of valid and alternative therapeutic interventions is essential to feed the urgent me...Dry eye disease(DED)is the most common eye disease in ophthalmic consultation except for refractive errors.Therefore,an exploration of valid and alternative therapeutic interventions is essential to feed the urgent medical need.It has been demonstrated that oxidative stress causes multiple adverse effects in the pathogenesis of DED,thence alleviating oxidative stress is an effective therapeutic strategy for the DED treatment.Herein,we developed a cerium oxide nanozyme combined with branched poly(ethylene imine)-graftpoly(ethylene glycol)(bPEI-g-PEG).Owing to its stable hydrophilic chains on the surface reducing the cytotoxicity and loads of amines groups that be combined with cerium ions through coordination bonds,the modified nanozymes(referred to as CNP@bPEI-g-PEG)are water soluble and highly biocompatible.Meanwhile,due to its excellent antioxidant activity,CNP@bPEI-g-PEG nanozymes can mimic the activity of superoxide dismutase and catalase to scavenge intracellular reactive oxygen species(ROS).Experimental studies firmly demonstrated that the modified nanozymes were auto-regenerative and more active in scavenging excessive ROS and alleviating oxidative stress by cerium-element valence state recycling,recovering the morphology of corneal,conjunctival epithelium and the number of goblet cells.The advanced combination may offer a superior therapeutic strategy to deal with oxidative stress for effective treatment of DED.展开更多
The catalytic conversion of polystyrene (PS) was studied in the presence of the materials type HZSM-5, CeO<sub>2</sub>, 10% CeO<sub>2</sub>/HZSM-5 and 20% CeO<sub>2</sub>/HZSM-5, wh...The catalytic conversion of polystyrene (PS) was studied in the presence of the materials type HZSM-5, CeO<sub>2</sub>, 10% CeO<sub>2</sub>/HZSM-5 and 20% CeO<sub>2</sub>/HZSM-5, which were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and nitrogen adsorption at 77K. The catalytic tests were performed via thermogravimetric analysis (TG) at heating rates of 5, 10 and 20˚C min<sup>−1</sup> in a temperature range from 30˚C to 900˚C. For the tests, a ratio of 30% by mass of each catalytic material mixed with PS was used and the activation energy of the degradation process was determined by the Vyazovkin method. The obtained results showed that the addition of the catalyst to the PS in general reduced its degradation temperature. The 10% CeO<sub>2</sub>/HZSM-5 catalyst showed greater efficiency, as it resulted in lower activation energy for PS degradation. Thus, the combination of CeO<sub>2</sub> with HZSM-5 resulted in materials with potential for application in the catalytic degradation of polystyrene and the results indicate that the production of a composite material can be a good strategy to generate an increase in catalytic activity and a decrease in energy process activation.展开更多
The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)...The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)and InOOH are formed,which are the precursors of stable cubic(c-In_(2)O_(3))and metastable rhombohedral(rh-In_(2)O_(3))phases,respectively.A transition from c-In_(2)O_(3)to rh-In_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-In_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)O_(3).The reverse situation is observed in composites based on c-In_(2)O_(3).Compared to In_(2)O_(3)and CeO_(2)–In_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100C,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)O_(3)and CeO_(2).展开更多
基金supported by Zhejiang Provincial Natural Science Foundation of China under Grant No.LYY21H300001Zhejiang Medical and Health Science and Technology project under Grant No.2021KY906Hangzhou Medical Key Discipline Construction Project under Grant No.[2021]21–39
文摘Psoriasis is an inflammatory skin disease that is intricately linked to oxidative stress.Antioxidation and inhibition of abnormal proliferation of keratinocytes are pivotal strategies for psoriasis.Delivering drugs with these effects to the site of skin lesions is a challenge that needs to be solved.Herein,we reported a nanotransdermal delivery system composed of all-trans retinoic acid(TRA),triphenylphosphine(TPP)-modified cerium oxide(CeO2)nanoparticles,flexible nanoliposomes and gels(TCeO_(2)-TRA-FNL-Gel).The results revealed that TCeO_(2)synthesized by the anti-micelle method,with a size of approximately 5 nm,possessed excellent mitochondrial targeting ability and valence conversion capability related to scavenging reactive oxygen species(ROS).TCeO_(2)-TRA-FNL prepared by the film dispersion method,with a size of approximately 70 nm,showed high drug encapsulation efficiency(>96%).TCeO_(2)-TRA-FNL-Gel further showed sustained drug release behaviors,great transdermal permeation ability,and greater skin retention than the free TRA.The results of in vitro EGF-induced and H2O2-induced models suggested that TCeO_(2)-TRA-FNL effectively reduced the level of inflammation and alleviated oxidative stress in HaCat cells.The results of in vivo imiquimod(IMQ)-induced model indicated that TCeO_(2)-TRA-FNL-Gel could greatly alleviate the psoriasis symptoms.In summary,the transdermal drug delivery system designed in this study has shown excellent therapeutic effects on psoriasis and is prospective for the safe and accurate therapy of psoriasis.
基金supported by National Natural Science Foundation of China(No.11875039)。
文摘The present study aims at the numerical simulations of the melting process of cerium oxide particles in RF thermal plasma.The physical model and the calculating method were described firstly;the interaction between cerium oxide particles and plasma was analyzed;specific attention was given to the effects of particle initial size,injection velocity on the particle melting and trajectory in plasma.The influence of the temperature field and velocity field distribution of the plasma around the particle trajectory on the melting effect is analyzed,and the relationship between the heat absorption efficiency of the particles and the particle size reduction process is further determined.It is also found that there exists an optimal particle initial injection velocity which led to a more concentrated final particle size distribution and a more significant reduction of particle size.The results could provide effective guidance for understanding the plasma spheroidization process of uranium dioxide and cerium dioxide powder particles.
文摘Oxaliplatin is a chemotherapeutic drug used for colorectal cancer treatment. The testicular toxic effect is one of its recorded toxicities which resulted in a few studies. Oxidative stress could be a direct cause of this testicular toxicity. Cerium oxide nanoparticles (CONPs) are optimistic antioxidants for applications in medicine. The aim of the work is to study the protective effect of CONPs on testicular toxicity induced by oxaliplatin in rats. Forty adult male albino rats were divided into 4 groups: Control group, CONPs group (60 mg/kg, 5 times/week), Oxaliplatin group (4 mg/kg, twice/week), and Oxaliplatin & CONPs group, for 4 weeks. Seventy-two hours after the last administration, blood samples were taken for hormonal levels and testes were used for both histopathology and immunohistochemical microscopic examination. Sperm smears were also performed and their results were statistically analyzed to detect any sperm abnormalities. Oxaliplatin increased MDA levels. SOD and GPx activity was decreased. GSH levels were decreased. Also, it decreased the sperm cell count and serum testosterone, and anti-Müllerian hormon. In the testicular sections, significant histopathology changes were seen and immunohistochemical examination confirmed these results. Upon supplementation of CONPs with oxaliplatin decreased MDA levels. SOD and GPx activity was increased, and GSH did not change. In testicular sections, normal morphology was seen. Also, there was an increase in the sperm cell count and serum testosterone anti-Müllerian with significant improvement of testicular architecture, and immunohistochemical examination confirmed these results. The utilization of CONPs produced significant protection against all of the above-mentioned changes.
文摘Cerium oxide nanoparticles(CNPs)possess a great potential as therapeutic agents due to their ability to self-regenerate by reversibly switching between two valences+3 and+4.This article reviews recent articles dealing with in vivo studies of CNPs towards Alzheimer’s disease,obesity,liver inflammation,cancer,sepsis,amyotrophic lateral sclerosis,acute kidney injury,radiation-induced tissue damage,hepatic ischemia reperfusion injury,retinal diseases and constipation.In vivo anti-cancer studies revealed the effectiveness of CNPs to reduce tumor growth and angiogenesis in melanoma,ovarian,breast and retinoblastoma cancer cell-induced mice,with their conjugation with folic acid,doxorubicin,CPM,or CXC receptor-4 antagonist ligand eliciting higher efficiency.After conjugation with triphenylphosphonium or magnetite nanoparticles,CNPs were shown to combat Alzheimer’s disease by reducing amyloid-β,glial fibrillary acidic protein,inflammatory and oxidative stress markers in mice.By improving muscle function and longevity,the citrate/EDTA-stabilized CNPs could ameliorate amyotrophic lateral sclerosis.Also,they could effectively reduce obesity in mice by scavenging ROS and reducing adipogenesis,triglyceride synthesis,GAPDH enzyme activity,leptin and insulin levels.In CCl4-induced rats,stress signaling pathways due to inflammatory cytokines,liver enzymes,oxidative and endoplasmic reticulum messengers could be attenuated by CNPs.Commercial CNPs showed protective effects on rats with hepatic ischemia reperfusion and peritonitis-induced hepatic/cardiac injuries by decreasing oxidative stress and hepatic/cardiac inflammation.The same CNPs could improve kidney function by diminishing renal superoxide,hyperglycemia and tubular damage in peritonitis-induced acute kidney injury in rats.Radiation-induced lung and testicular tissue damage could be alleviated in mice,with the former showing improvement in pulmonary distress and bronchoconstriction and the latter exhibiting restoration in spermatogenesis rate and spermatid/spermatocyte number.Through enhancement of gastrointestinal motility,the CNPs could alleviate constipation in both young and old rats.They could also protect rat from light-induced retinal damage by slowing down neurodegenerative process and microglial activation.
文摘CeO2 nanometer powders of different sizes were prepared at low temperature by pyrolysis of amorphous citrate. XRD patterns show that CeO2 is cubic in structure, space group Oh5-FM3M·TEM indicates that the prepared CeO2 is spherical in shape, and the particle size distribution is in narrow range. It was found that calcination temperature is a more important factor affecting the crystallite size of CeO2 than calcining time, the smaller the particle. the bigger the crystallattice distortion, the worse the crystal growth. Solubility test of CeO2 in nitric acid reveals that the surface activity of CeO2 decreases with the increasing particle sizes. IR spectra analysis shows that the absorption of Ce-O bond is shifted to higher energy with the decrease of CeO2 particle sizes.
基金[The project was financially supported by the National Science Foundation of China.]
文摘Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt back- ground and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The cathodic reaction mechanism of the molten salt background was: O2+e - O2-2;O2+2NO-3→2NO-2+2O02. According to the results of SEM and XPS, cerium oxide film, which is composed of CeO2, can form on the nickel electrode at - 1.850 V vs. Ag/ AgNO3(0.1mol/L) reference electrode.
文摘Glasses and glass ceramics in the system xCeO<sub>2·</sub>(50 - x)PbO·50B<sub>2</sub>O<sub>3</sub> (0 ≤ x ≤ 50) have been studied, for the first time, by NMR and FTIR techniques. Effect of CeO<sub>2</sub> substitution with PbO on NMR parameters has been discussed in terms of changing both boron and cerium coordination. The quantitative fraction of four coordinated boron (N<sub>4</sub>) has been simply determined from <sup>11</sup>B NMR spectroscopy. On the other hand, the fraction of total tetrahedral structural units B<sub>4</sub> (BO<sub>4</sub> + PbO<sub>4</sub> + CeO<sub>4</sub>) is obtained from FTIR spectral analysis. It is not possible to get the fraction of cerium oxide directly from the applied spectroscopic tools. Therefore, a simple approach is applied, for the first time, to determine CeO<sub>4</sub> fraction by using the different criteria of both <sup>11</sup>B NMR and FTIR spectroscopy. The fraction of B<sub>4</sub> species is equal to N<sub>4</sub>, within the experimental error, of the same glasses in the composition region of up to 10 mol% CeO<sub>2</sub>. On the other hand, there is a clear difference between both N<sub>4</sub> and B<sub>4</sub> values in glasses of higher CeO<sub>2 </sub>content (>10 mol%). The related difference showed a linear increasing trend with increasing the content of CeO<sub>2</sub> in the glass. This was discussed on the bases of structural role of CeO<sub>2</sub> which acts as a glass former in the region >10 mol%, while, at lower concentration, it consumed as a glass modifier.
文摘Crystalline cubic cerium oxide nano particles have been synthesized from cerium(Ⅲ)nitrate(Ce(NO_(3))_(3).6H2_(O))and sodium hydroxide by a hydrothermal method.The effect of three different molar ratios of the NaOH precipitating agent on structural,optical,and photo catalytic activity was investigated.The synthesized cerium oxide nano particles were characterized by X-ray diffraction(XRD),a UV-vis spectrometer,scanning electron microscope(SEM),energy-dispersive X-ray spectroscopy(EDAX),Raman spectroscopy and X-ray photo electron spectroscopy(XPS).According to the findings,hydrothermally synthesized cerium oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light.Environmental water pollution is the major issue of the atmosphere.To get fresh water,humans could search the resources to purify the water in simple way and degradation is the one of the methods to purify salt water.
文摘Co-precipitation was used to prepare cerium oxide nano-particles. The effects of aging temperature and concentration of cobalt ion on the optical property, morphology, and particle size were investigated. The cerium oxide was prepared by adding ammonia solution into a mixed solution of cerium nitrate with cobalt nitrate solutions to obtain a large amount of precipitates and then aged further. Subsequently, the precipitates were kept in an oven for calcination keeping the temperature at 400?C for lasting 24 h. The average size of cerium oxide particles was obtained from the (111) peak in the X-ray diffraction pattern using the Scherrer equation. The crystal sizes obtained were found to be in the range of 11.82 - 13.47 nm. The results showed that the particle size decreased with an increase in the Co ion concentration and decreased with an increase in temperature. The SEM pictures show that the morphology for cerium oxide is granular and/or columnar. It can be seen from UV/Vis absorption spectrum that the maximum absorption peaks were in the range of 334 - 390 nm, depending on the operating conditions. The corresponding energy gaps were observed in the range of 3.18 - 3.71 eV. Subsequently, the Brus equation for the energy gap was discussed. Finally, particle size was correlated with the aging temperature and Co ion concentration.
基金Project supported by the Indian Society of Pedodontics and Preventive Dentistry (ISPPD/2022/111)。
文摘Nanotechnology deals with particles ranging from 1 to 100 nm in size called as nanoparticles.These nano particles exhibit unique properties which find an application in many industries and medical fields.A growing body of evidence points out the newer developing technologies adopted in the field of medicine in terms of target therapies,imaging systems,drug deliveries,etc.is through the incorporation of nanoparticles.Cerium oxide nanoparticles have gained attention in the last decade due to exceptional properties such as redox activity,biofilm inhibition,antibacterial activity,anti-inflammatory activity,etc.The method of synthesis of cerium oxide nanoparticles plays a pivotal role in its application.It exhibits redox properties and catalytic activity and thus has found its use in biomedical applications.Nanoparticles are incorporated into dental materials such as restorative cements/sealants,adhesives,and denture systems to improve their properties.Among the various metal oxide nanoparticles,ce rium oxide nanoparticles(CeO_(2)NPs)are known to exhibit lower toxicity to mammalian cells and possess unique antibacterial mechanism.In addition,they exhibit potent properties such as antitumor,antiinflammatory,antibacterial activities,and functions as an immunosensor.CeO_(2)NPs have excellent scavenging properties for reactive oxygen species,which is why they are being considered for therapeutic purposes.In this review,various methods of synthesis of CeO_(2)NPs are discussed.Several factors that determine the particle size and morphology of these materials are important for biomedical and dental applications.Emphasis is given to preparation methods and variables such as calcination temperature,which have a profound effect on particle size and morphology.This article also presents various applications of CeO_(2)NPs in the biomedical and dental fields.
基金University of Central Florida(ER Award:#25089A06)We would also like to acknowledge the National Science Foundation(NSF)Major Research Instrumentation(MRI)Program(Grant ID:ECCS:1726636)for the XPS measurements presented in this manuscript+6 种基金MM acknowledges the University of Huddersfield(UoH)EPSRC-DTP competition 2018–19(EP/R513234/1)for funding SMVice Chancellor’s Scholarship Scheme for funding KMTAnalysis was performed on the Orion computing facility at the UoH.Calculations were run on the ARCHER and ARCHER2 UK National Supercomputing Services via our membership of the UK HEC Materials Chemistry Consortium(MCCEPSRC EP/L000202,EP/R029431)AA acknowledges NIH NCI(Grant R01CA045424),Research Excellence Fund(REF)Center for Biomedical Research for support.AA also acknowledges the National Science Foundation(NSF)instrumentation award(CHE-1920110)JA’s work was supported by the National Aeronautics and Space Administration[grant No.80NSSC21M0309]issued through the NASA Office of STEM Engagement.
文摘The disability,mortality and costs due to ionizing radiation(IR)-induced osteoporotic bone fractures are sub-stantial and no effective therapy exists.Ionizing radiation increases cellular oxidative damage,causing an imbalance in bone turnover that is primarily driven via heightened activity of the bone-resorbing osteoclast.We demonstrate that rats exposed to sublethal levels of IR develop fragile,osteoporotic bone.At reactive surface sites,cerium ions have the ability to easily undergo redox cycling:drastically adjusting their electronic con-figurations and versatile catalytic activities.These properties make cerium oxide nanomaterials fascinating.We show that an engineered artificial nanozyme composed of cerium oxide,and designed to possess a higher fraction of trivalent(Ce^(3+))surface sites,mitigates the IR-induced loss in bone area,bone architecture,and strength.These investigations also demonstrate that our nanozyme furnishes several mechanistic avenues of protection and selectively targets highly damaging reactive oxygen species,protecting the rats against IR-induced DNA damage,cellular senescence,and elevated osteoclastic activity in vitro and in vivo.Further,we reveal that our nanozyme is a previously unreported key regulator of osteoclast formation derived from macrophages while also directly targeting bone progenitor cells,favoring new bone formation despite its exposure to harmful levels of IR in vitro.These findings open a new approach for the specific prevention of IR-induced bone loss using synthesis-mediated designer multifunctional nanomaterials.
基金funding support from the School of Pharmacy,University of Pittsburgh(SS),Brenneman Fund,University of Pittsburgh(KME)Graduate Student Research Scholarship from the School of Pharmacy,University of Pittsburgh(AP)special BD LSRFORTESSATM funded by NIH 1S10OD011925-01(PI:Borghesi).
文摘Respiratory syncytial virus(RSV)is the most common cause of viral bronchiolitis among children worldwide,yet there is no vaccine for RSV disease.This study investigates the potential of cube and sphere-shaped cerium oxide nanoparticles(CNP)to modulate reactive oxygen(ROS)and nitrogen(RNS)species and immune cell phenotypes in the presence of RSV infection in vitro and in vivo.Cube and sphere-shaped CNP were synthesized by hydrothermal and ultrasonication methods,respectively.Physico-chemical characterization confirmed the shape of sphere and cube CNP and effect of various parameters on their particle size distribution and zeta potential.In vitro results revealed that sphere and cube CNP differentially modulated ROS and RNS levels in J774 macrophages.Specifically,cube CNP significantly reduced RSV-induced ROS levels without affecting RNS levels while sphere CNP increased RSV-induced RNS levels with minimal effect on ROS levels.Cube CNP drove an M1 phenotype in RSV-infected macrophages in vitro by increasing macrophage surface expression of CD80 and CD86 with a concomitant increase in TNFαand IL-12p70,while simultaneously decreasing M2 CD206 expression.Intranasal administration of sphere and cube-CNP were well-tolerated with no observed toxicity in BALB/c mice.Notably,cube CNP preferentially accumulated in murine alveolar macrophages and induced their activation,avoiding enhanced uptake and activation of other inflammatory cells such as neutrophils,which are associated with RSV-mediated inflammation.In conclusion,we report that sphere and cube CNP modulate macrophage polarization and innate cellular responses during RSV infection.
基金financially supported by the National Natural Science Foundation of China (No.51904069)the Natural Science Foundation of Hebei Province of China (No.E2019501085)+2 种基金the Colleges and Universities in Hebei Province Science and Technology Research Youth Fund (No.QN2019312)the Fundamental Research Funds for the Central Universities (No.N172303012)the National Science and Technology Support Program (No.2012BAE01B02)
文摘Ultrafine rare-earth oxides(REOs) are widely applied in all fields of daily life,but the conventional preparation methods are limited by a long procedure,low efficiency and severe environmental pollution.Our team has independently developed a jet pyrolysis reactor for the preparation of ultrafine cerium oxides,and this process has theoretical significance and practical application values.In this study,gas-solid pyrolysis reactions inside the jet-flow pyrolysis reactor were numerically simulated.We performed a coupling computation of the combustion,phase transformation and gas-solid reaction on Fluent and userdefined functions.We characterized the flows of different phases as well as the compositions and distributive laws of the reactants/products in the reactor.The gas-phase inlet velocity and dynamic pressure/additional pressure were related by a quadratic function.The velocity at the throat inlet changed the most,and the outlet velocity was very stable.The CeO2 concentrations were obviously stratified.This study enriches theories of jet-flow pyrolysis and theoretically underlies the optimization and popularization of self-developed pyrolysis reactors.
基金supported by the National Natural Science Foundation of China(Grant Nos.51672283 and 51902271)the Fundamental Research Funds for the Central Universities(Grant Nos.A1920502051907-15,2682020CX07,and 2682020CX08)+3 种基金Sichuan Science and Technology Program(Grant Nos.2020YJ0259 and 2020YJ0072)Doctoral Research Start-up Fund of Hebei GEO University(Grant No.BQ2019003)Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(Grant No.18LHPY009)Liaoning Baiqianwan Talents Program。
文摘A novel arsenic adsorbent with hydrous cerium oxides coated on glass fiber cloth(HCO/GFC)was synthesized.The HCO/GFC adsorbents were rolled into a cartridge for arsenic removal test.Due to the large pores between the glass fibers,the arsenic polluted water can flow through easily.The arsenic removal performance was evaluated by testing the equilibrium adsorption isotherm,adsorption kinetics,and packed-bed operation.The pH effects on arsenic removal were conducted.The test results show that HCO/GFC filter has high As(Ⅴ)and As(Ⅲ)removal capacity even at low equilibrium concentration.The more toxic As(Ⅲ)in water can be easily removed within a wide range of solution p H without pre-treatment.Arsenic contaminated ground-water from Yangzong Lake(China)was used in the column test.At typical breakthrough conditions(the empty bed contact time,EBCT=2 min),arsenic researched breakthrough at over 24,000 bed volumes(World Health Organization(WHO)suggested that the maximum contaminant level(MCL)for arsenic in drinking water is 10 mg/L).The Ce content in the treated water was lower than 5 ppb during the column test,which showed that cerium did not leach from the HCO/GFC material into the treated water.The relationship between dosage of adsorbents and the adsorption kinetic model was also clarified,which suggested that the pseudo second order model could fit the kinetic experimental data better when the adsorbent loading was relatively low,and the pseudo first order model could fit the kinetic experimental data better when the adsorbent loading amount was relatively high.
文摘Inadequate angiogenesis is a hallmark of conditions including cardiovascular diseases,stroke and chronic diabetic wounds,which exhibit tissue ischaemia ensuring that therapeutic strategies to promote angiogenesis are of great interest.However,many angiogenic treatments involve the delivery of growth factors which have limited clinical success due to poor stability,high manufacturing cost and poor efficacy.Cerium oxide nanoparticles(nanoceria)can either promote or inhibit angiogenesis depending on their surface corona chemistry.Here,nanoceria were functionalized with an intentional heparin corona,a polysaccharide which binds and signals growth factors,of different chain lengths and surface grafting density to establish their effect on angiogenesis.These nanoparticles promoted angiogenesis in vivo with the surface grafting density positively correlated with angiogenesis over the widest concentration range;however,chain length did not play a role.The heparin–nanoceria supported fibroblast growth factor 2(FGF2)signalling in vitro and promoted FGF2-mediated angiogenesis in vivo.The nanoparticles were internalized by endothelial cells in vitro where they trafficked to the lysosomes and reduced cell viability suggesting that the angiogenic activity of heparin–nanoceria is mediated in the extracellular environment.Together,this study adds to our knowledge of the angiogenic effects of heparin–nanoceria towards finding new angiogenic treatments.
基金financially supported by Funding of Jiangsu Educational Committee (No. 19KJB430042)。
文摘In general, inorganic filler/polyurethane elastomer(PUE) composites possess favorable properties, such as modulus, chemical resistance, and heat stability, are promising for broadening the application area of polyurethanes(PU). For the experiments, a series of cerium oxide(CeO_(2))/PUE composites were prepared with different sizes and appearance of CeO_(2), and different mixing methods as well. CeO_(2) particles with different sizes were added into PUs during the formation of urethane linkage and the chain-extend process, respectively. The morphology along with mechanical properties, thermal properties of the composites were studied. The results suggest that the size of CeO_(2) and mixing methods influence the microstructure of PUs which has profound effect on properties of these composites. The composites tend to form more quantity of hard domains(HDs) with small size when CeO_(2) particles were added before the formation of urethane linkage, whereas Ce O2 particles increase the size of HDs when added with chain extender into PU prepolymer.
基金financially supported by the National Natural Science Foundation of China(Nos.51901062 and U1908220)the Natural Science Foundation of Zhejiang Province(No.LR18E010001)+1 种基金the Key R&D Project of Zhejiang Province(Nos.2019C01121 and 2021C01023)the LiaoNing Revitalization Talents Program(No.XLYC1807177)。
文摘Cerium oxide possesses intrinsic hydrophobic properties ascribed to the unique electronic structure.However,the relationship between the crystal structure and hydrophobicity of cerium oxide has not been systematically studied.Herein,it is experimentally and theoretically demonstrated that the water contact angle(105.9°)of the(111)surface is higher than that(91.7°)of the(220)surface,associated with the lower surface free energy(28.44 mN/m)of(111)surface than that(38.48 mN/m)of(220)surface.Furthermore,cerium oxide films with(111)-terminated surface are annealed at 300℃ and 600℃ for1 h,respectively.The lattice constant increases(5.4594Å<5.4613Å<5.4670Å)with decreasing the annealing temperature(600℃>300℃>the as-deposited),leading to the increased water contact angle(96.7°<96.8°<99.0°).The First-principles calculation provides microscopic insights into the wetting mechanism,originating from the weakened adsorption capacity of the(111)surface for water molecules with the increasing lattice constant.
基金financially supported by the Key Scientific and Technological Innovation Projects in Wenzhou[ZY2021002]the Medical&Health Technology Program of Zhejiang Province[2022RC051].
文摘Dry eye disease(DED)is the most common eye disease in ophthalmic consultation except for refractive errors.Therefore,an exploration of valid and alternative therapeutic interventions is essential to feed the urgent medical need.It has been demonstrated that oxidative stress causes multiple adverse effects in the pathogenesis of DED,thence alleviating oxidative stress is an effective therapeutic strategy for the DED treatment.Herein,we developed a cerium oxide nanozyme combined with branched poly(ethylene imine)-graftpoly(ethylene glycol)(bPEI-g-PEG).Owing to its stable hydrophilic chains on the surface reducing the cytotoxicity and loads of amines groups that be combined with cerium ions through coordination bonds,the modified nanozymes(referred to as CNP@bPEI-g-PEG)are water soluble and highly biocompatible.Meanwhile,due to its excellent antioxidant activity,CNP@bPEI-g-PEG nanozymes can mimic the activity of superoxide dismutase and catalase to scavenge intracellular reactive oxygen species(ROS).Experimental studies firmly demonstrated that the modified nanozymes were auto-regenerative and more active in scavenging excessive ROS and alleviating oxidative stress by cerium-element valence state recycling,recovering the morphology of corneal,conjunctival epithelium and the number of goblet cells.The advanced combination may offer a superior therapeutic strategy to deal with oxidative stress for effective treatment of DED.
文摘The catalytic conversion of polystyrene (PS) was studied in the presence of the materials type HZSM-5, CeO<sub>2</sub>, 10% CeO<sub>2</sub>/HZSM-5 and 20% CeO<sub>2</sub>/HZSM-5, which were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and nitrogen adsorption at 77K. The catalytic tests were performed via thermogravimetric analysis (TG) at heating rates of 5, 10 and 20˚C min<sup>−1</sup> in a temperature range from 30˚C to 900˚C. For the tests, a ratio of 30% by mass of each catalytic material mixed with PS was used and the activation energy of the degradation process was determined by the Vyazovkin method. The obtained results showed that the addition of the catalyst to the PS in general reduced its degradation temperature. The 10% CeO<sub>2</sub>/HZSM-5 catalyst showed greater efficiency, as it resulted in lower activation energy for PS degradation. Thus, the combination of CeO<sub>2</sub> with HZSM-5 resulted in materials with potential for application in the catalytic degradation of polystyrene and the results indicate that the production of a composite material can be a good strategy to generate an increase in catalytic activity and a decrease in energy process activation.
基金supported by the Russian Science Foundation(grant No.22-19-00037),https://rscf.ru/project/22-19-00037/.
文摘The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)and InOOH are formed,which are the precursors of stable cubic(c-In_(2)O_(3))and metastable rhombohedral(rh-In_(2)O_(3))phases,respectively.A transition from c-In_(2)O_(3)to rh-In_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-In_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)O_(3).The reverse situation is observed in composites based on c-In_(2)O_(3).Compared to In_(2)O_(3)and CeO_(2)–In_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100C,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)O_(3)and CeO_(2).
