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1.
Chemosphere ; 274: 129766, 2021 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-33529955

RESUMO

The removal of organic pollutants from water environments is a challenging problem. Fe-based BC (Fe-BC) composites are promising catalysts for generating reactive oxygen species (ROS) for environmental remediation considering their low costs and excellent physicochemical surface characteristics. The synthesis methods, properties, applications, and the mechanism of Fe-BC for removing pollutants are reviewed. Various methods have been used to prepare Fe-BC composites, and the synthetic methods and conditions used affect the properties of the Fe-BC material, thereby influencing its pollutant removal performance. The mechanisms of pollutant removal by Fe-BC are intricate and include adsorption, degradation and reduction. Fe loading on BC could improve the performance of BC by affecting its surface area, surface functional groups and electron transfer rate. Moreover, research gaps and uncertainties that exist in the use of Fe-BC were identified. Finally, the problems that need to be solved to make Fe-BC suitable for future applications are described.

2.
Biochem Biophys Res Commun ; 547: 52-58, 2021 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-33592379

RESUMO

Natural products are useful tools for biological mechanism research and drug discovery. Due to the excellent tumor cell growth inhibitory profile and sub-nanomolar potency, Coibamide A (CA), an N-methyl-stabilized depsipeptide isolated from marine cyanobacterium, has been considered as a promising lead compound for cancer treatment. However, the molecular anti-cancer mechanism of the action of CA remains unclear. Here, we showed that CA treatment induced caspase-independent cell death in breast cancer cells. CA treatment also led to severe lysosome defects, which was ascribed to the impaired glycosylation of lysosome membrane protein LAMP1 and LAMP2. As a consequence, the autophagosome-lysosome fusion was blocked upon CA treatment. In addition, we presented evidence that this autophagy defect partially contributed to the CA treatment-induced tumor cell death. Together, our work uncovers a novel mechanism underlying the anti-cancer action of CA, which will promote its further application for cancer therapy.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 252: 119548, 2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33601222

RESUMO

Novel color-adjustable phosphors Sr8MgCe(PO4)7:Tb3+ were synthesized by the solid-state reaction method. The X-ray diffraction was used to characterize the phase formation. The host shows blue emission under 310 nm excitation, ascribed to the 5d-4f transitions of Ce3+, while Sr8MgCe(PO4)7:xTb3+ phosphors exhibit the emission band of Ce3+ as well as the characteristic lines of Tb3+ under 310 nm excitation. The color variation was observed as the concentration of Tb3+ changes. Moreover, the host sensitizes the emission of Tb3+ through the energy transfer process, and the mechanism is the dipole-dipole interaction. In addition, the emission of the host declines with the increase of the temperature while that of Tb3+ increases. This anti-thermal quenching behavior was interpreted by the configurational coordinate diagram. In addition, the temperature sensing behavior based on the emission peaks of the host and Tb was studied in the range 298-523 K, and the largest sensitivity is 0.379% K-1. The results indicate that Sr8MgCe(PO4)7:Tb3+ is an attractive color-tunable phosphor for solid state lighting and temperature sensing.

4.
Sci Rep ; 11(1): 3887, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33594109

RESUMO

Tobacco bacterial wilt (TBW) caused by Ralstonia solanacearum is the most serious soil-borne disease of tobacco. However, molecular mechanism information of R. solanacearum resistance is limited to tobacco, hindering better breeding of resistant tobacco. In this study, the expression profiles of the rootstalks of Yunyan87 (susceptible cultivar) and Fandi3 (resistant cultivar) at different stages after R. solanacearum infection were compared to explore molecular mechanisms of tobacco resistance against the bacterium. Findings from gene-expression profiling indicated that the number of upregulated differentially expressed genes (DEGs) at 3 and 7 days post-inoculation (dpi) increased significantly in the resistant cultivar. WRKY6 and WRKY11 family genes in WRKY transcription factors, ERF5 and ERF15 family genes in ERFs transcription factors, and genes encoding PR5 were significantly upregulated in the resistant cultivar response to the infection. For the first time, WRKY11 and ERF15 were found to be possibly involved in disease-resistance. The Kyoto Encyclopedia of Genes and Genomes analysis demonstrated glutathione metabolism and phenylpropane pathways as primary resistance pathways to R. solanacearum infection. In the resistant cultivar, DEGs encoding CYP450, TCM, CCoAOMT, 4CL, PAL, CCR, CSE, and CADH, involved in the synthesis of plant antitoxins such as flavonoids, stilbenoids, and lignins, enriched in the phenylpropane pathway were upregulated at 3 and 7 dpi. Furthermore, a pot experiment was performed to verify the role of flavonoids in controlling TBW. This study will strongly contribute to a better understanding of molecular interactions between tobacco plants and R. solanacearum.

5.
Mater Sci Eng C Mater Biol Appl ; 120: 111670, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33545835

RESUMO

Tumor cell membrane-derived nanostructures targeting homologous tumors are promising biomimetic drugs. Herein, curcumin (Cur) and chlorin e6 (Ce6) were co-loaded into PLGA nanoparticles (NPs), and then the NPs were coated with MCF-7 cell membranes (MCNPs). Cell membrane coating sharply increased the uptake of MCNPs by homologous cells, as compared to that with naked NPs. The NPs co-loaded with Cur and Ce6 (Cur/Ce6-NPs) showed a stronger proliferation-inhibitory effect on MCF-7 cells than the NP groups loaded with Cur and Ce6 alone. Cytotoxicity and apoptosis rates of MCF-7 cells in the Cur/Ce6-MCNPs group were significantly higher than those in the uncoated Cur/Ce6-NPs group. Both Cur/Ce6-NPs and Cur/Ce6-MCNPs significantly inhibited the migration of MCF-7cells, although Cur/Ce6-MCNPs showed a stronger effect. Compared to that of Cur/Ce6-NPs, the elimination of Cur/Ce6-MCNPs was both decreased and retarded, prolonging their in vivo systemic circulation and resulting in improved bioavailability. After intravenous administration for 24 h, the fluorescence intensity of drugs in the liver and spleen of the Cur/Ce6-MCNPs group was significantly weaker than that in the Cur/Ce6-NPs group, but that in tumor tissue was enhanced. Further, Cur/Ce6-MCNPs treatment achieved significantly better tumor-suppressive effects in vivo than Cur/Ce6-NPs, resulting in smaller tumor weights, increased apoptosis rates, and the down regulation of Ki67 protein in the tumor tissue. Thus, the tumor cell membrane-camouflaged nanocomposites have potential for homologous tumor-targeted therapy. Furthermore, photodynamic therapy combined with chemotherapy has promising future prospects.

6.
Aging (Albany NY) ; 132021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33582655

RESUMO

Metabolic syndrome (MetS) is characterized by a group of metabolic disturbances which leads to the enhanced risk of cancer development. Elucidating the mechanisms between these two pathologies is essential to identify the potential therapeutic molecular targets for colorectal cancer (CRC). 716 colorectal patients from the First and Second Affiliated Hospital of Wenzhou Medical University were involved in our study and metabolic disorders were proven to increase the risk of CRC. The prognostic value of the MetS factors was analyzed using the Cox regression model and a clinical MetS-based nomogram was established. Then by using multi-omics techniques, the distinct molecular mechanism of MetS genes in CRC was firstly systematically characterized. Strikingly, MetS genes were found to be highly correlated with the effectiveness of targeted chemotherapy administration, especially for mTOR and VEGFR pathways. Our results further demonstrated that overexpression of MetS core gene IL6 would promote the malignancy of CRC, which was highly dependent on mTOR-S6K signaling. In conclusion, we comprehensively explored the clinical value and molecular mechanism of MetS in the progression of CRC, which may serve as a candidate option for cancer management and therapy in the future.

7.
J Phys Chem Lett ; : 1726-1733, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33566624

RESUMO

Recently, two-dimensional layered perovskites have emerged as effective additives for stabilizing conventional three-dimensional metal halide perovskites. With the addition of layered perovskites, the perovskite-based devices also exhibited enhanced optoelectronic properties, such as reduced nonradiative recombination and ionic migration, strengthened crystallinity, and anisotropic charge transport. However, the influence of the large organic cations on the performance metrics of the photodiodes is not fully understood. In this work, we systematically investigate the device performance and related optoelectronic features of the layered perovskite-enhanced perovskite photodiodes. In particular, with the addition of large organic cations to the FA0.83Cs0.17PbI3 perovskite matrix, the devices exhibited reduced dark current and noise, increased detectivity of >1013 Jones, and a consistent high speed of <100 ns. More importantly, the layered perovskite-enhanced photodiodes exhibited less hysteresis and higher breakdown voltages.

8.
Artigo em Inglês | MEDLINE | ID: mdl-33387207

RESUMO

The coagulation factor VII (FVII) gene R353Q polymorphism is suggested to be relevant to the coronary heart disease (CHD) susceptibility. However, the results of separate studies are not consistent with one another. A meta-analysis including 3258 participants from nine studies was conducted to investigate the relationship between the FVII gene R353Q polymorphism and the CHD in the Chinese population. The fixed-effect models were used to assess the pooled odds ratios (ORs) and their corresponding 95% confidence intervals. A significant association was observed between the FVII gene R353Q polymorphism and the CHD in the Chinese population under allelic (OR 1.34, 95% CI 1.10-1.65, P = 0.004), dominant (OR 0.68, 95% CI 0.55-0.85, P = 0.0006), and heterozygous (OR 0.68, 95% CI 0.55-0.85, P = 0.0007) genetic models. The FVII gene R353Q polymorphism was significantly correlated with the CHD susceptibility in the Chinese population. Persons with the R allele of the FVII gene R353Q polymorphism might have greater CHD risk than others.

9.
J Med Internet Res ; 23(1): e23410, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33502326

RESUMO

BACKGROUND: Despite potential for benefit, mindfulness remains an emergent area in perinatal mental health care, and evidence of smartphone-based mindfulness training for perinatal depression is especially limited. OBJECTIVE: The objective of this study was to evaluate the effectiveness of a smartphone-based mindfulness training intervention during pregnancy on perinatal depression and other mental health problems with a randomized controlled design. METHODS: Pregnant adult women who were potentially at risk of perinatal depression were recruited from an obstetrics clinic and randomized to a self-guided 8-week smartphone-based mindfulness training during pregnancy group or attention control group. Mental health indicators were surveyed over five time points through the postpartum period by online self-assessment. The assessor who collected the follow-up data was blind to the assignment. The primary outcome was depression as measured by symptoms, and secondary outcomes were anxiety, stress, affect, sleep, fatigue, memory, and fear. RESULTS: A total of 168 participants were randomly allocated to the mindfulness training (n=84) or attention control (n=84) group. The overall dropout rate was 34.5%, and 52.4% of the participants completed the intervention. Mindfulness training participants reported significant improvement of depression (group × time interaction χ24=16.2, P=.003) and secondary outcomes (χ24=13.1, P=.01 for anxiety; χ24=8.4, P=.04 for positive affect) compared to attention control group participants. Medium between-group effect sizes were found on depression and positive affect at postintervention, and on anxiety in late pregnancy (Cohen d=0.47, -0.49, and 0.46, respectively). Mindfulness training participants reported a decreased risk of positive depressive symptom (Edinburgh Postnatal Depression Scale [EPDS] score>9) compared to attention control participants postintervention (odds ratio [OR] 0.391, 95% CI 0.164-0.930) and significantly higher depression symptom remission with different EPDS reduction scores from preintervention to postintervention (OR 3.471-27.986). Parity did not show a significant moderating effect; however, for nulliparous women, mindfulness training participants had significantly improved depression symptoms compared to nulliparous attention control group participants (group × time interaction χ24=18.1, P=.001). CONCLUSIONS: Smartphone-based mindfulness training is an effective intervention in improving maternal perinatal depression for those who are potentially at risk of perinatal depression in early pregnancy. Nulliparous women are a promising subgroup who may benefit more from mindfulness training. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1900028521; http://www.chictr.org.cn/showproj.aspx?proj=33474.

10.
Mol Med Rep ; 23(3): 1, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33398363

RESUMO

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy and the second leading cause of cancer­related mortality worldwide according to Global Cancer Statistics 2018. Resveratrol (RSV) is a phenolic compound that possesses anticancer functions against various types of cancer, including breast and gastric cancer. However, the functions and mechanism underlying RSV in CRC are not completely understood. The present study aimed to investigate the anticancer effects and mechanism underlying RSV in CRC cells by conducting Cell Counting Kit­8, apoptosis, reactive oxygen species (ROS) and western blotting assays. The results suggested that RSV dose­dependently inhibited CRC cell viability, and increased cell apoptosis and ROS levels compared with the control group. The protein expression levels of Bax, cytochrome c, cleaved caspase­9 and cleaved caspase­3 were upregulated, whereas Bcl­2 expression levels were downregulated in RSV­treated CRC cells compared with control cells. The results indicated that RSV might activate the mitochondrial apoptotic pathway by increasing ROS release. The present study suggested that RSV possessed antitumour activity against CRC by modulating an ROS­mediated mitochondrial apoptotic pathway.

11.
Artigo em Inglês | MEDLINE | ID: mdl-33418194

RESUMO

MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level. Although the regulatory roles of miRNAs in various physiological processes throughout insect development have been investigated, it is almost unknown about the roles of miRNAs involved in regulation of diapause in insects. We constructed nine small RNA libraries from Galeruca daurica adults at different diapause stages: pre-diapause (PD), diapause (D), and post-diapause (TD). Using Illumina sequencing, a total of 95.06 million valid reads was obtained, and 222 miRNAs, including 135 conserved and 87 novel miRNAs, were identified from G. daurica. The expression profiles of these miRNAs were analyzed across different diapause stages. The 30 and 13 miRNAs were differentially expressed in the D/PD and TD/D comparisons, respectively. The KEGG and GO analysis of the predicted target genes suggested the essential roles of miRNAs in the regulation of summer diapause in G. daurica, especially via the juvenile hormone, ribosome, MAPK signaling, and Ca2+ signaling pathways. Our research results indicate that miRNAs may be involved in the regulation of summer diapause in G. daurica, and these results also provide an important new small RNA genomics resource for further studies on insect diapause.

12.
Biomacromolecules ; 22(2): 918-926, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33427463

RESUMO

The synthesis of optically pure polymers is one of the most challenging tasks in polymer chemistry. Herein, Novozym 435 (Lipase B from Candida antarctica, immobilized on Lewatit VP OC 1600)-catalyzed polycondensation between d-/l-aspartic acid (Asp) diester and diols for the preparation of helical chiral polyesters was reported. Compared with d-Asp diesters, the fast-reacting l-Asp diesters easily reacted with diols to provide a series of chiral polyesters containing N-substitutional l-Asp repeating units. Besides amino acid configuration, N-substituent side chains and the chain length of diols were also investigated and optimized. It was found that bulky acyl N-substitutional groups like N-Boc and N-Cbz were more favorable for this polymerization than small ones probably due to competitively binding of these small acyl groups into the active site of Novozym 435. The highest molecular weight can reach up to 39.5 × 103 g/mol (Mw, D = 1.64). Moreover, the slow-reacting d-Asp diesters were also successfully polymerized by modifying the substrate structure to create a "nonchiral" condensation environment artificially. These enantiocomplementary chiral polyesters are thermally stable and have specific helical structures, which was confirmed by circular dichroism (CD) spectra, scanning electron microscope (SEM), and molecular calculation.

13.
Anal Bioanal Chem ; 2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33483838

RESUMO

Herein, we developed a novel effervescence-assisted dual microextraction method, abbreviated as EM-LPSH, using lighter-than-water phosphonium-based ionic liquids (LPILs) and switchable hydrophilic/hydrophobic fatty acids (SHFAs). The EM-LPSH method was utilized for quick enrichment/extraction of polycyclic aromatic hydrocarbons (PAHs) in edible oils. Owing to lower density than water, LPILs used as the first extractant were floated on the upper layer of the aqueous phase, leading to a convenient separation/collection compared with traditional heavier-than-water imidazolium-based ionic liquids. Interestingly, SHFAs play triple functions: a dispersive solvent in the microextraction process, an acidic source in effervescent reaction, and the second extractant in dual microextraction, due to switchability from hydrophilicity to hydrophobicity. Consequently, the integration of LPILs with SHFAs greatly enhanced the extraction efficiency for PAHs owing to the quick dual microextraction process. Some important variables were rigorously optimized using a one-factor-at-a-time approach. Under optimized conditions, the EM-LPSH/HPLC-FLD method provided a wide linear range (0.07~0.63-200 µg kg-1), satisfactory recovery (80.12-103.27%), and low limit of detection (0.02-0.19 µg kg-1), as well as high intra-day and inter-day precision (0.03-6.55) for six PAHs in edible oils. By using certified reference material in olive oil samples (GBW10162), the recoveries ranged from 97.40 to 98.39%, demonstrating high accuracy and precision. According to the detected levels of PAHs in six unheated and heated oils, their edible safety was evaluated in detail. In short, the newly developed method is simple, convenient, and highly efficient, thereby showing great prospects for application in conventional monitoring of trace-level PAHs in edible oils.

14.
Sci Rep ; 11(1): 2653, 2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514837

RESUMO

Bacterial wilt as a soil-borne disease was caused by Ralstonia solanacearum, and seriously damages the growth of tobacco. Integrated biocontrol method was explored to control bacterial wilt. Nevertheless, the long-term effects of the integrated biocontrol method on soil bacterial community, soil physicochemical properties and the incidence of bacterial wilt are not well understood. In this study, B. amyoliquefaciens ZM9, calcium cyanamide and rice bran were applied to tobacco fields in different ways. The disease index and incidence of tobacco bacterial wilt (TBW), soil physicochemical properties, colonization ability of B. amyoliquefaciens ZM9, and rhizopshere bacterial community were investigated. The results showed that the integrated application of B. amyoliquefaciens ZM9, rice bran and calcium cyanamide had the highest control efficiency of TBW and bacteria community diversity. Additionally, the integrated biocontrol method could improve the colonization ability of B. amyoliquefaciens ZM9. Furthermore, the integrated biocontrol method could effectively suppress TBW by regulating soil physicochemical properties, promoting beneficial bacteria and antagonistic bacteria of rhizopshere soil. This strategy has prospect of overcoming the defects in application of a single antagonistic bacteria and provides new insights to understand how to improve the colonization capacity of antagonistic bacteria and control efficacy for TBW.

15.
Chemosphere ; 263: 128178, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297146

RESUMO

The reproductive toxicity of fluoride (F) has been verified by various epidemiological and experimental studies. Our previous work suggested that the interleukin 17A (IL-17A) is involved in the testicular damage induced by excessive F exposure. In this study, we further investigated the role of IL-17A in F-induced testicular injury. Wild type (WT) and IL-17A knockout (IL-17A-/-) mice were exposed to 0, 25, 50, or 100 mg/L sodium fluoride (NaF) for 90 days. We found that exposure to excessive F levels caused testicular damage, decreased semen quality, negatively affected testicular morphology, and increased the inflammatory response. Specifically, excessive F intake increased the expression levels of IL-17A in the testis and increased the protein levels of Act1, NF-κB, IL-17R, C/EBP-α, and TRAF6 in the IL-17A signaling pathway. The increase in IL-17A expression corresponded to increases expression of IL-17R, IL-6, IL-23, IL-1ß, TGF-ß and TNF-α as assessed by RT-PCR and ELISA assays. Remarkably, IL-17A knockout in mice ameliorated the effects of F on testicular damage, semen quality, testicular morphology, and the immune response. Additionally, we found the in vitro exposure of Leydig cells to NaF and recombinant IL-17A led to abnormal apoptosis and a decrease in testosterone secretion. Our findings prove that IL-17A plays a key role in the exacerbation of testicular injuries in F-exposed mice, and that IL-17A deficiency can alleviate F-induced injury by inhibiting the immune response and apoptosis in the testis. These data suggest that targeting IL-17A may be a useful therapeutic strategy for treating F-mediated toxicity in the testis.


Assuntos
Fluoretos , Interleucina-17 , Animais , Apoptose , Humanos , Imunidade , Interleucina-17/genética , Masculino , Camundongos , Análise do Sêmen
16.
J Cell Physiol ; 236(1): 55-67, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32583417

RESUMO

Sedentary and high-calorie diets are associated with increased risk of obesity and type 2 diabetes mellitus, while exercise and diet control are also important nondrug treatments for diabetes. Fibroblast growth factor 21 (FGF21) is an important cytokine, which is mainly expressed in liver, fat and muscle tissue responding to nutrition and exercise, and plays an important role in the improvement of glucose and lipid metabolism. Due to the increasing serum FGF21 level in obesity and diabetes, FGF21 can be used as a predictor or biomarker of diabetes. A variety of clinical antidiabetic drugs can reduce the content of FGF21, possibly for the improvement of FGF21 sensitivity. In this paper, we reviewed the interactions between FGF21 and nondrug therapy (diet and exercise) for diabetes and explored the potential value of the combined application of clinical antidiabetic drugs and FGF21.

18.
Onco Targets Ther ; 13: 12383-12395, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33299327

RESUMO

Background: Cervical squamous cell carcinoma (CSCC) is responsible for 80-85% of cervical cancer. Cyclin B1 (CCNB1) represents a hub gene during the development of cervical cancer. However, the oncogenic role of CCNB1 in CSCC remains unclear. Our study aims to explore the mechanism underlying CCNB1 regulation on cell cycle progression in CSCC cells. Methods: First, we analyzed differentially expressed genes from CSCC dataset GSE63678 and conducted gene function enrichment analysis. Subsequently, CCNB1 expression was knocked down in CSCC cell lines to assess cell proliferation, apoptosis, and cell cycle distribution. After the validation of the binding relationship between forkhead box protein M1 (FOXM1) and the promoter of CCNB1, the effect of FOXM1 on CCNB1 expression and on CSCC cell growth and apoptosis was verified. We further analyzed the histone ChIP-Seq data of CCNB1 in CSCC cells and measured the acetylation levels of the CCNB1 promoter histones. Results: CCNB1 was overexpressed in CSCC tissues and cells, and CCNB1 silencing inhibited the growth of CSCC cells, and promoted cell cycle arrest and apoptosis. FOXM1 potentiated CCNB1 transcription by binding to its promoter and recruiting CBP/P300, a histone acetyltransferase. Further increasing FOXM1 expression or increasing P300 activity in CSCC cells with CCNB1 knockdown elevated CCNB1 expression and proliferation and cell cycle progression of CSCC cells. Knockdown of CCNB1 activated the p53 pathway in cells. Conclusion: FOXM1 inhibited the activation of the p53 pathway by recruiting CBP/P300, which promoted the transcription of CCNB1, resulting in the growth and cell cycle progression of CSCC cells.

19.
Spectrochim Acta A Mol Biomol Spectrosc ; 248: 119247, 2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-33302216

RESUMO

In order to explore diverse luminescence properties of Eu3+ in inorganic phosphors, a series of novel deep-red-emitting Ca2Ga2GeO7 phosphors were successfully synthesized by solid-state reactions. The phase formation was verified by the X-ray diffraction patterns and Rietveld refinement and there is only one kind of Ca2+ site in Ca2Ga2GeO7. The excitation spectrum shows typical excitation peaks of Eu3+ and the broad band ranging from 200 nm to 300 nm was composed of the charge transfer band of O2--Eu3+ and Ga3+-O2- transition band. The emission spectrum depicts that the intensity of the peak located at 704 nm (5D0 â†’ 7F4) is higher than that of 618 nm (5D0 â†’ 7F2), which finally leads to the deep-red emission of the phosphor with high color saturation. The coordination dodecahedron of EuO8 distorted from a cubic geometry to the square antiprism is responsible for the unusual emission of Eu3+. The research of the concentration quenching behavior, lifetime and luminescence decay curves imply that the energy transfer between Eu3+ ions finally leads to the concentration quenching, and the interaction type is d-d interaction. The charge compensation, quantum efficiency and the thermal stability of Ca2Ga2GeO7:Eu3+ were also studied.

20.
Artigo em Inglês | MEDLINE | ID: mdl-33356112

RESUMO

Two-dimensional (2D) mesoporous materials have received substantial research interest due to their highly exposed active sites and unusual nanoconfinement effect. However, controllable and efficient synthesis of 2D mesoporous materials and investigation of their intrinsic properties have remained quite rare. Herein, a general and effective surface-limited cooperative assembly (SLCA) method enabled by leveling precursor solutions on KCl crystals via centrifugation is employed to conveniently synthesize two-dimensional (2D) monolayer mesoporous materials with different compositions. This novel strategy is performed in a manner similar to spin coating, not only enabling generation of ultrathin mesostructured composite film on KCl particles and recycling excessive precursor solution but also providing favorable solvent annealing environment for the film to form ordered mesostructures. Taking monolayer mesoporous Ce0.8Zr0.2O2 solid solutions as a sample, they display ultrathin nanosheet morphology with a thickness of ∼20 nm, highly open porous structure, and easily accessible active sites of surface superoxide species. Upon decoration of 2D mesoporous Ce0.8Zr0.2O2 nanosheets with Pt nanoparticles, the obtained catalyst exhibits superior catalytic activity and stability toward CO oxidation with a low onset temperature of 30 °C and a 100% conversion temperature of 95 °C, which are 35-70 °C lower than those for their counterpart materials, namely, three-dimensional (3D) mesoporous Pt/Ce0.8Zr0.2O2. Moreover, their TOFPt value is ∼11.3 times higher than that of 3D mesoporous Pt/Ce0.8Zr0.2O2. Characterizations based on various techniques indicate that such an outstanding catalytic performance is due to the ultrashort distance (20 nm) of mass diffusion, highly exposed active sites, rich surface-chemisorbed oxygen, and the synergistic effect between the Ce0.8Zr0.2O2 matrix and Pt species.

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