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1.
Artigo em Inglês | MEDLINE | ID: mdl-32011799

RESUMO

Herein, the trackable supramolecular transformation of a two-component molecular cage to a three-component cage through supramolecular fusion with another two-component molecular square is described. The use of tetraphenylethene (TPE), a chromophore with aggregation-induced emission (AIE) character, as a component for the molecular cages enables facile fluorescence monitoring of the transformation process: while both cages exhibit fluorescence emission via the restriction of intramolecular motion of the TPE motif, the interactions between TPE and 4,4'-bipyridine introduced in the supramolecular fusion process result in partial fluorescence quenching and shifts in the emission maximum. This study provides a simple and efficient approach towards complex supramolecular cages with emergent functions and demonstrates that AIE features could provide unique opportunities for the characterization of complex, dynamic supramolecular transformation processes.

2.
J Am Chem Soc ; 142(4): 2051-2058, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31905287

RESUMO

Supramolecular polymers based on host-guest molecular recognition have emerged as promising platforms for the development of smart materials. However, the studies on them are primarily conducted in solution and/or in the gel state. In contrast, little is known about dynamic properties and applications of supramolecular polymers in bulk. Herein, we present a self-cross-linking supramolecular polymer network (SPN) as a model system to understand the bulk properties controlled by noncovalent interactions. Specifically, the SPN monomer is composed of two benzo-21-crown-7 (B21C7) host units and two dialkylammonium salt guest moieties on a four-arm core, wherein complementary host-guest complexation drives the formation of the SPN with [2]pseudorotaxane linkages between B21C7 and ammonium motifs. The dynamic and reversible behaviors of the linkages are evaluated by measurement of viscoelasticity. The results indicate that the host-guest molecular recognition becomes highly dynamic at elevated temperature. Moreover, the relatively high activation energy of the SPN manifests itself as a new type of thermoplastic material with network topology freezing glass transition. Finally, we demonstrate how these findings provide insights into the malleability and processability of the SPN by simple demos. The fundamental understanding gained from the research on this SPN in bulk will facilitate the advancement and application of supramolecular materials.

3.
4.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 33(6): 666-670, 2019 Jun 15.
Artigo em Chinês | MEDLINE | ID: mdl-31197990

RESUMO

Objective: To explore the effectiveness of proximal femoral nail antirotation (PFNA) assisted by mesh locator in treatment of intertrochanteric fracture in the elderly. Methods: Ninety-four elderly patients with intertrochanteric fractures admitted between August 2014 and July 2017 were selected as the study subjects. They were randomly divided into trial group (48 cases) and control group (46 cases). In trial group, PFNA was implanted assisted by mesh locator after closed reduction; while in control group, PFNA was implanted by conventional method. There was no significant difference between the two groups in terms of gender, age, cause of injury, time from injury to admission, fracture side and classification, and medical complications ( P>0.05). The operation time, intraoperative blood loss, fluoroscopy times, hospital stay, incision length, and complications were recorded. Visual analogue scale (VAS) was used to evaluate the degree of pain at 3 days after operation, and Harris score was used to evaluate hip function before operation and at 3, 6, and 9 months after operation. Results: Compared with control group, the operation time and incision length of trial group shortened, the blood loss and fluoroscopy times reduced, the pain after operation alleviated obviously; the differences between the two groups were significant ( P<0.05). There was no significant difference in hospital stay between the two groups ( P>0.05). The patients in both groups were followed up 9-12 months, with an average of 10.6 months. X-ray films showed that the fractures healed in both groups, and the healing time in control group was (11.2±3.2) weeks, while that in trial group was (11.6±2.9) weeks, showing no significant difference between the two groups ( t=1.262, P=0.120). There was no significant difference in Harris score between the two groups before operation and at 3, 6, and 9 months after operation ( P>0.05). There was 1 case of incision infection, 2 cases of coxa vara, and 1 case of pressure ulcer in trial group, and the incidence of complications was 8.3%. There was 1 case of coxa vara, 2 cases of pressure ulcer, and 1 case of internal fixation loss in control group, and the incidence of complications was 8.7%. There was no significant difference in the incidence of complications between the two groups (χ 2=0.783, P=0.112). Conclusion: It is feasible to implant PFNA assisted by mesh locator in treatment of intertrochanteric fracture in the elderly. Compared with the traditional operation, it can shorten the operation time, shorten the incision, and relieve the pain after operation.


Assuntos
Fixação Intramedular de Fraturas , Fraturas do Quadril , Idoso , Pinos Ortopédicos , Fêmur , Fraturas do Quadril/cirurgia , Humanos , Telas Cirúrgicas , Resultado do Tratamento
5.
J Am Chem Soc ; 141(24): 9673-9679, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31125220

RESUMO

The intrinsic relationship between the properties of green fluorescent protein (GFP) and its encapsulated small molecular light machine has spurred many biomimicking studies, aiming at revealing the detailed mechanism and further promoting its wide applications in different disciplines. However, how to build a similar confined microenvironment to mimic the cavity of a ß-barrel and the fluorescence turn-on process is a fundamental challenge for both chemists and biologists. Herein, two distinct exo- and endo-functionalized tetraphenylethylene (TPE)-based M12L24 nanospheres with precise distribution of anchored TPE moieties and unique photophysical properties were constructed by means of a coordination-driven self-assembly strategy. Under dilute conditions, the nanospheres fluoresce more strongly than the corresponding TPE subcomponents. Meanwhile, the endo-functionalized sphere is able to induce a higher local concentration and more restrained motion of the enclosed 24 TPE units compared with exo-functionalized counterpart and thus induces much stronger emission due to the restriction of the rotation of the pendant TPE units. The biomimetic methodology developed here represents a promising way to understand and construct artificial GFP materials on the platforms of supramolecular coordination complexes.

6.
Nat Mater ; 18(4): 357-363, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30742082

RESUMO

Quantum interference can profoundly affect charge transport in single molecules, but experiments can usually measure only the conductance at the Fermi energy. Because, in general, the most pronounced features of the quantum interference are not located at the Fermi energy, it is highly desirable to probe charge transport in a broader energy range. Here, by means of electrochemical gating, we measure the conductance and map the transmission functions of single molecules at and around the Fermi energy, and study signatures associated with constructive and destructive interference. With electrochemical gate control, we tune the quantum interference between the highest occupied molecular orbital and lowest unoccupied molecular orbital, and directly observe anti-resonance, a distinct feature of destructive interference. By tuning the molecule in and out of anti-resonance, we achieve continuous control of the conductance over two orders of magnitude with a subthreshold swing of ~17 mV dec-1, features relevant to high-speed and low-power electronics.

7.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 26(6): 1610-1615, 2018 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-30501692

RESUMO

OBJECTIVE: To investigate whether the down-regulation of miR-125b can reverse the drug-resistence of doxorubicine-resistant leukemia cell lines or not, so as to explore a new method for treatment of drug-resistant leukemia patients. METHODS: The expression levels of miR125b in doxorubicine drug-sensitive and doxorubicine drug-resistant leukemia cell lines.HL-60, K562 and HL-60/Dox, the K562/Dox were detected by using RT-qPCR; the up-regulation or inhibition of miR-1256 expression in HL-60/Dox were performed by electroporation transfection, then the viability of cells treated with doxorubicine of different concentration was detected by CCK-8 method, the proliferation inhibition curve of cells was drawed, and the IC50 was calculated. RESULTS: The miR-125b expression was obviously up-regulated in drug-resistant cell lines HL-60/DOX and K562/DOX, as compared with HL-60 and K562 cell lines. The miR-125b expression level in HL-60/DOX and K562/DOX cells was 15 times and 5 times higher than that in HL-60 and K562 cells, respectively. The up-regulating or inhibiting expression of miR-125b in HL-60/DOX cells found that the proliferation inhibition rate in cells transfected with miR-125b mimic significantly decreased, compared with control group (P<0.01), while the proliferation inhibition rate in cells transfected with miR-125b inhibitor significantly increased, compared with control group(P<0.01). CONCLUSION: The miR-125b expression in HL-60/Dox and K562/Dox cells has been up-regulated, down-regulation of miR-125b expression can reverse the drug resistance of leukemia cells to doxorubicine.


Assuntos
Regulação para Baixo , Leucemia , Doxorrubicina , Resistencia a Medicamentos Antineoplásicos , Humanos , Células K562 , MicroRNAs
8.
Exp Ther Med ; 16(3): 2665-2669, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30186499

RESUMO

The present study aimed to verify the expression and investigate the role of microRNA (miR)-148a in intervertebral disc degeneration (IDD) and explore the associated underlying mechanisms. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to investigate levels of miR-148a in the peripheral blood mononuclear cells (PBMCs) of patients with IDD. To investigate the role of miR-148a in IDD, a stable miR-148a-overexpression/underexpression human nucleus pulposus (NP) cell line was generated by transfection with miR-148a mimic/inhibitor. Then, NP cells were treated with LPS (10 µM) to induce inflammation. The mRNA expression level of miR-148a in NP cells was determined by RT-qPCR and the expression levels of p38 and p-p38 were measured using western blotting. The mRNA expression and supernatant level of pro-inflammatory cytokines, tumor necrosis factor (TNF-α), interleukin (IL)-1ß and IL-6, was evaluated by RT-qPCR and ELISA, respectively. The results indicated that miR-148a was significantly downregulated in the PBMCs of IDD patients compared with healthy controls. In vitro upregulation of miR-148a in LPS-stimulated NP cells, by transfection with miR-148a mimic, resulted in inhibition of p-p38 expression; however, inhibition of miR-148a led to overexpression of p-p38. Meanwhile, the production of pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6) was significantly reduced in miR-148a-overexpressing LPS-stimulated NP cells and significantly increased in miR-148a-underexpressing NP cells. In conclusion, miR-148a inhibits pro-inflammatory cytokines released by intervertebral disc cells via regulation of the p38/mitogen-activated protein kinase pathway.

9.
J Org Chem ; 83(10): 5577-5587, 2018 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-29698606

RESUMO

Six-membered azaborine rings have been straightforwardly fused on naphthalimide-based donor-acceptor systems, and a series of BN-containing heteroaromatic compounds BN1-BN3 were constructed. Electron-donating triphenylamines were functionalized in the extended direction of the 3- or/and 4-position of the naphthalimide unit. For comparison, reference BN0 without triphenylamine was also prepared. The intramolecular charge transfer (ICT) interactions in the resulting BN-fused naphthalimides (BN0-BN3) together with their precursors (N0-N3) and fluoride-coordinated analogues (FBN0-FBN3) have been systematically investigated by photophysical, electrochemical, and theoretical approaches. It is found that the fusion of the azaborine ring has a great effect on the ICT properties of the D-A systems based on BN-fused naphthalimides. For the precursors without boron, the extension of an electron donor from the 3-position of naphthalimide is superior in enhancing the D-A interactions. On the contrary, upon fusion of the azaborine ring on naphthalimide, the dominant orientation of the ICT interactions conversely converts to the extended direction of the 4-position of naphthalimide in the D-A molecules based on BN-fused naphthalimides. Most interestingly, upon coordinating the boron by a fluoride ion, the ICT interactions are dramatically enlarged and the substitution position of the triphenylamino group has a negligible effect on the ICT properties of the fluoride-coordinated analogues.

10.
Biochem Biophys Res Commun ; 499(4): 765-771, 2018 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-29605301

RESUMO

Increasing evidences demonstrate the essential roles of circular RNAs (circRNAs) in human cancers. However, the study about the functions of circRNAs in glioma remains very limited. In the present study, we found that circRNA hsa_circ_0007534 was highly expressed in glioma tissues compared to normal brain tissues. Furthermore, we found that knockdown of hsa_circ_0007534 significantly inhibited the proliferation and migration of glioma cells. In mechanism, we showed that hsa_circ_0007534 could sponge miR-761 to repress its availability in glioma cells. We found that inhibition of miR-761 could rescue the suppressed proliferation and migration of glioma cells by hsa_circ_0007534 knockdown. Moreover, we explored the downstream mechanism and found that ZIC5 was a target of miR-761. We showed that hsa_circ_0007534 promoted the expression of ZIC5 by inhibiting miR-761 in glioma cells. And restoration of ZIC5 expression significantly reversed the effects of hsa_circ_0007534 knockdown on glioma cell proliferation and migration. In summary, our results demonstrated that hsa_circ_0007534 serves as an oncogene in glioma via promoting ZIC5 expression by repressing miR-761 availability. Our results suggested that hsa_circ_0007534/miR-761/ZIC5 regulatory loop might be a promising therapeutic target for glioma treatment.


Assuntos
Movimento Celular/genética , Glioma/genética , Glioma/patologia , MicroRNAs/metabolismo , RNA/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células/genética , Técnicas de Silenciamento de Genes , Humanos , MicroRNAs/genética , RNA/genética , Regulação para Cima/genética
11.
World Neurosurg ; 109: e778-e782, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29074421

RESUMO

OBJECTIVE: Hemifacial spasm (HFS) is a disorder characterized by intermittent, involuntary facial muscle contractions. Microvascular decompression (MVD) is the gold treatment for HFS. The aim of this research was to discuss whether patients undergoing MVD as their initial surgical intervention experience greater spasm control than patients experiencing an MVD performed as a subsequent surgical intervention. METHODS: The study included 976 patients with HFS, 452 of whom (group A) underwent MVD as their initial surgical intervention and 524 of whom (group B) underwent subsequent MVD. Relevant clinical data including outcome of MVD, operative findings, complications, and so on were collected immediately after MVD operation and at follow-up. RESULTS: The follow-up period was 7-9 years (mean, 7.96 ± 0.87 years). The mean age at intervention was 53.14 years and 55.43 years in the 2 groups, respectively. The long-term postoperative relief rate of patients in the 2 groups was 98.23% and 87.21%, respectively. There was a significant difference in long-term postoperative relief rate of patients between the 2 groups (P < 0.05). CONCLUSIONS: Patients undergoing MVD for HFS as the primary treatment experience better long-term efficacy than patients first treated with botulinum neurotoxin type A.


Assuntos
Espasmo Hemifacial/diagnóstico , Espasmo Hemifacial/cirurgia , Cirurgia de Descompressão Microvascular/métodos , Cirurgia de Descompressão Microvascular/tendências , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
12.
J Am Chem Soc ; 139(8): 2989-2993, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28068761

RESUMO

Using two tetraphenylbenzene isomers differing only by the anchoring points to the gold electrodes, we investigate the influence of quantum interference on the single molecule charge transport. The distinct anchor points are realized by selective halogen-mediated binding to the electrodes by formation of surface-stabilized isomers after iodine cleavage. Both isomers are essentially chemically identical and only weakly perturbed by the electrodes avoiding largely parasitic effects, which allows us to focus solely on the relation between quantum interference and the intrinsic molecular properties. The conductance of the two isomers differs by over 1 order of magnitude and is attributed to constructive and destructive interference. Our ab initio based transport calculations compare very well with the accompanying scanning tunneling microscope break junction measurements of the conductance. The findings are rationalized using a two level model, which shows that the interorbital coupling plays the decisive role for the interference effects.

13.
Appl Biochem Biotechnol ; 175(7): 3244-57, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25686559

RESUMO

The aim of this study was to synthesize a chitosan (CS) derivative, a quaternary ammonium salt crystal called N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC), and test a series of HACC and pEGFP-DNA complexes at different weight ratios for their efficiency of gene delivery into human cells. CS was modified with cationic etherifying agent to obtain the CS derivative. Fourier transform infrared spectra were recorded on KBr pellets with a spectrometer. (1)H nuclear magnetic resonance (NMR) spectra of HACC were obtained using a spectrometer. HACC was subsequently used to prepare HACC/DNA complexes at different weight ratios by coacervation method. The resulting particle size and surface charge were assessed by laser light scattering using a zeta potential analyzer. The HACC/DNA complex formation and DNA protection in the nanoparticle complex was investigated by gel mobility shift assay and DNase I protection assay, respectively. The cytotoxicity of HACC and HACC/DNA nanoparticles was evaluated by MTT assay using (mesenchymal stem cell) MSC lines. The nanoscale structure of the particles was obtained by transmission electron microscope (TEM). The FTIR spectrum of HACC showed the characteristic quaternary ammonium group absorption band at 1475 cm(-1), which indicated the presence of quaternary ammonium group. The successful synthesis of HACC was also confirmed by (1)H NMR spectrum. HACC showed good solubility in water and was electropositive. HACC efficiently packed and protected pEGFP-DNA at a weight ratio of 10. With increased weight ratios, the surface charge of the composite particle increased from negative to positive, the average particle size increased, and HACC nanoparticle had a higher carrying efficiency. The nanoparticles released DNA in two distinct phases, and 55 % was released within the first 20 h of solubilization. The nanoparticles under TEM showed circular or oval shapes. The particles exhibited no cytotoxicity against human cells. No significant difference in gene delivery efficiency was detected between HACC/pEGFP-GDNF and liposome/pEGFP-GDNF complexes (33.8 vs. 34 %, P = 0.363). In this study, HACC was successfully synthesized, and HACC/DNA complex assembled efficiently. HACC showed strong DNA binding affinity and high protection of DNA and was non-cytotoxic to human cells. The particles had appropriate nanostructure, mean diameter, and DNA release time. The results suggest that HACC nanoparticles are a novel tool for efficient and safe gene delivery.


Assuntos
DNA/genética , Técnicas de Transferência de Genes , Terapia Genética , Nanopartículas/química , Linhagem Celular Tumoral , Quitosana/análogos & derivados , DNA/administração & dosagem , DNA/química , Proteínas de Fluorescência Verde/administração & dosagem , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Humanos , Espectroscopia de Ressonância Magnética , Nanopartículas/administração & dosagem , Transfecção
14.
Int J Clin Exp Med ; 8(11): 21796-801, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26885144

RESUMO

OBJECTIVE: The objective of this study was to investigate the clinical curative effect of stage I repair of acute injuries of the lateral ligament complex of the ankle by the application of suture anchors. METHODS: We retrospectively analyzed 18 cases of III degree acute injuries of the lateral ligament complex of the ankle. RESULTS: There were statistically significant differences in preoperative and last follow-up VAS pain scores and AOFAS ankle hind-foot function scores. The X-ray talus displacement values in the anterior drawer test and pressure anteroposterior X-ray talar tilt in the ankle talar tilt test also showed statistically significant differences. Complications occurred in 2 patients, incision surface infection in one, and postoperative lateral dorsal skin numbness in one. All these cases were cured after symptomatic treatment. At the last follow-up all patients' ankle joint activity recovered to their preinjury function levels. CONCLUSION: The application of suture anchors for small incision stage I repair of the lateral collateral ligament of ankle joint degree III injury, can effectively restored the stability of ankle joint, and prevent the occurrence of chronic ankle instability complications. It is effective and feasible for the treatment of ankle joint lateral collateral ligament injuries.

15.
Neurochem Int ; 61(7): 1011-20, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22841891

RESUMO

Apoptosis of cholinergic neurons is one of the core hallmarks of Alzheimer's disease. SH-SY5Y neuroblastoma cells differentiated to the cholinergic phenotype were exposed to 100nM staurosporine. Over a treatment period of 24h, the pro- and anti-apoptotic factors, caspase-3 and Bcl-2, as well as LDH release as a measure of cell viability, were assessed in conjunction with the number of apoptotic cells by means of fluorescence-activated cell sorting. Caspase-3 activity and LDH release increased by 30% and 20% over controls, respectively, while Bcl-2 levels rose by 200% over controls. Furthermore, staurosporine treatment resulted in decreased acetylcholinesterase (AChE) enzymatic activity and decreased protein levels of the AChE splice variant tailed AChE (AChE-T). Only a slight increase in levels of readthrough AChE (AChE-R) was observed. Likewise, staurosporine reduced levels and activity of the cholinergic players choline acetyltransferase and high affinity choline uptake. The present study demonstrates that treatment with staurosporine leads to apoptotic events, which, however, are not reflected in the increased AChE activity and the alterations of AChE isoforms expression that are usually seen in apoptotic conditions. The effects of various additional phosphorylation inhibitors on AChE activity suggest that these unexpected cholinergic effects, firstly, are linked to the impact of staurosporine on phosphorylation and, secondly, reveal themselves in a first phase of cellular adaption that precedes neurotoxicity and subsequent cell death.


Assuntos
Apoptose/efeitos dos fármacos , Diferenciação Celular , Inibidores Enzimáticos/farmacologia , Neuroblastoma/patologia , Receptores Colinérgicos/metabolismo , Estaurosporina/farmacologia , Acetilcolinesterase/metabolismo , Western Blotting , Caspase 3/metabolismo , Linhagem Celular Tumoral , Eletroforese em Gel de Poliacrilamida , Humanos , L-Lactato Desidrogenase/metabolismo , Neuroblastoma/enzimologia , Neuroblastoma/metabolismo , Fosforilação
16.
J Hazard Mater ; 189(1-2): 150-7, 2011 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-21371821

RESUMO

A series of ceria-zirconia-neodymia mixed oxides with different contents of neodymia and the supported Pd-only three-way catalysts before and after aging have been prepared and characterized. The influence of Nd doping on the structural/textural properties of ceria-zirconia (CZ) and the effect on the three-way catalytic performance are also investigated. The results demonstrate that the addition of neodymia results in the formation of ceria-zirconia-neodymia ternary solid solution (CZN) with better textural and structural properties as well as improved reducibility and redox behavior, leading to the promoted three-way catalytic activity and enlarged air/fuel operation window. The modified solid solution with 5 wt.% neodymia shows the preferable textural/structural properties considering that the capacity of foreign cation is limited in the crystal lattice of ceria-zirconia solid solution, and Pd/CZN5 shows the optimum three-way catalytic performance and wider air/fuel operation window, especially for the corresponding aged one.


Assuntos
Catálise , Cério , Neodímio , Emissões de Veículos/prevenção & controle , Zircônio , Ar , Gasolina , Oxirredução
17.
J Hazard Mater ; 186(1): 911-20, 2011 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21177019

RESUMO

Ce(0.67)Zr(0.33)O(2) doped with iron oxide was prepared and the corresponding Pd-only three-way catalysts were examined and characterized. Pd/CZFe(1%) catalyst exhibits the best catalytic performance for CO, HC, NO and NO(2) elimination and the widest operation window. The doping of iron oxide with 1% loading suggests the formation of more homogeneous Ce-Zr-Fe-O ternary solid solution, which seems to facilitate the reduction of Ce(4+)→Ce(3+) or the formation of oxygen vacancy and to promote the interaction between Ce-Zr and Fe. Moreover, the Ce redox behaviour for surface reduction suggests depending not only on the formation of homogeneous Ce-Zr-Fe-O but also on the surface property of the sample. The increase in the concentration of oxygen vacancies under all atmospheres for CZFe(1%) sample also results in the enhancement of oxygen storage complete capacity.


Assuntos
Cério/química , Ferro/química , Emissões de Veículos , Zircônio/química , Catálise , Análise Espectral Raman , Difração de Raios X
18.
Environ Sci Technol ; 44(10): 3870-5, 2010 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-20408547

RESUMO

Automotive exhaust emission is a major cause of air pollution. Three-way catalyst (TWC) which can eliminate CO, HC (hydrocarbons), and NO(x) simultaneously has been used to control exhaust emissions. Ceria-zirconia is a key component in TWC and most researchers pay attention to Ceria-Zirconia (Ce-rich) solid solution. The research presented in this paper is focused on the intrinsic structure of Ceria-Zirconia (Zr-based) solid solution and its application in TWC. A series of Ce(0.2)Zr(0.8)O(2) modified with rare earths (La, Nd, Pr, Sm, and Y) have been prepared by coprecipitation method combined with supercritical drying technique. All samples showed single tetragonal solid solution, indicating that the rare earth ion inserted into the lattice structure completely, and an approximately linearly relationship between lattice parameter a and the ionic radius of doped rare earth was observed. The catalytic performances of corresponding Pd-only catalysts were investigated in simulated exhaust gas. The presence of La, Nd, and Pr was favorable to the catalytic activity and wide air/fuel operation window. The relationship between the intrinsic structure of the Zr-based ceria-zirconia solid solution and catalytic activity was discussed in detail, which has some reference value for catalyst design and application.


Assuntos
Cério/química , Metais Terras Raras/química , Emissões de Veículos , Zircônio/química , Catálise
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