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1.
J Econ Entomol ; 113(1): 461-470, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32034919

RESUMO

Hormone-dependent responses in host plants induced by herbivore infestation have species-specific effects. This study focused on determining the relative expression profiles of the genes associated with hormone-dependent pathways in two near-isogenic wheat lines when attacked by cereal aphids. Infestation with Rhopalosiphum padi Linnaeus (Hemiptera: Aphididae) and/or Sitobion avenae Fabricius (Hemiptera: Aphididae) significantly upregulated the expression of marker genes related to the salicylic acid (SA)- and jasmonic acid (JA)-dependent pathways in the tested lines. In the resistant line 35-E4, previous infestation with R. padi significantly increased the relative expression of plant pathogenesis-related protein 1 at all sampling times but did not have a significant effect on the expression of the phenylalanine ammonia-lyase (PAL) gene. In addition, the expression levels of the lipoxygenase (LOX) and allene oxide synthase (AOS) genes immediately increased after the aphid attack. In susceptible line 35-A20, infestation with either R. padi or S. avenae led to significantly increased expression levels of the AOS and PAL genes. Moreover, sequential aphid infestation induced higher expression of AOS compared with a single-species aphid infestation, whereas the expression of the PAL gene was antagonistically affected by sequential aphid infestation. Overall, these results showed that aphid infestation induced SA- and JA-dependent responses in host plants. However, the expression profiles of these genes in resistant and susceptible host lines were significantly different.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31980915

RESUMO

BACKGROUND: The chemokine MIP-3α (CCL20) binds to CCR6 on immature dendritic cells. DNA vaccines fusing MIP-3α to melanoma-associated antigens have shown improved efficacy and immunogenicity in the B16F10 mouse melanoma model. Here, we report that the combination of type-I interferon therapy (IFNα) with 5-Aza-2'-deoxycitidine (5Aza) profoundly enhanced the therapeutic efficacy of a MIP-3α-Gp100-Trp2 DNA vaccine. METHODS: Beginning on day 5 post-transplantation of B16F10 melanoma, vaccine was administered intramuscularly (i.m.) by electroporation. CpG adjuvant was given 2 days later. 5Aza was given intraperitoneally at 1 mg/kg and IFNα therapy either intratumorally or i.m. as noted. Tumor sizes, tumor growth, and mouse survival were assessed. Tumor lysate gene expression levels and tumor-infiltrating lymphocytes (TILs) were assessed by qRT-PCR and flow cytometry, respectively. RESULTS: Adding IFNα and 5Aza treatments to mice vaccinated with MIP-3α-Gp100-Trp2 leads to reduced tumor burden and increased median survival (39% over vaccine and 95% over controls). Tumor lysate expression of CCL19 and CCR7 were upregulated ten and fivefold over vaccine, respectively. Vaccine-specific and overall CD8+ TILs were increased over vaccine (sevenfold and fourfold, respectively), as well as the proportion of TILs that were CD8+ (twofold). CONCLUSIONS: Efficient targeting of antigen to immature dendritic cells with a chemokine-fusion vaccine offers an alternative to classic and dendritic cell vaccines. Combining this approach with IFNα and 5Aza treatment significantly improved vaccine efficacy. This improved efficacy correlated with changes in chemokine gene expression and CD8+ TIL infiltration and was dependent on the presence of all therapeutic components.

3.
J Sep Sci ; 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31981302

RESUMO

The present study aimed to develop a strategy involving quantitative analysis of multi-components by single marker in combination with HPLC fingerprint qualitative analysis for performing the quality control of Aurantii Fructus. The content of 12 components (eriocitrin, neoeriocitrin, narirutin, naringin, hesperidin, neohesperidin, meranzin, poncirin, naringenin, nobiletin, tangeretin, and auraptene) in samples was determined using reliable relative correction factors that were obtained using naringin as an internal reference standard. The new method demonstrated good applicability, and no significant differences were observed between the external standard method and the new method as determined by calculating standard method difference. Qualitative evaluation of samples was conducted using similarity analysis, hierarchical cluster analysis, and quality fluctuation analysis. Chromatographic fingerprint data were divided into three groups by similarity and hierarchical cluster analyses, and seven components may have a more significant impact on the quality of Aurantii Fructus in quality fluctuation analysis. Overall, the study suggests that the qualitative and quantitative analyses of multi-components using quantitative analysis of multi-components by single marker combined with chromatographic fingerprinting, can be considered good quality criteria for performing quality control and providing technical support for the further pharmacological and pharmaceutical research of Aurantii Fructus. This article is protected by copyright. All rights reserved.

4.
Emerg Microbes Infect ; 9(1): 111-123, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31906823

RESUMO

The Zika virus (ZIKV) is a mosquito-borne flavivirus that causes neonatal abnormalities and other disorders. Antibodies to the ZIKV envelope (E) protein can block infection. In this study, next-generation sequencing (NGS) of immunoglobulin heavy chain (IgH) mRNA transcripts was combined with single-cell PCR cloning of E-binding monoclonal antibodies for analysing antibody response in a patient from the early stages of infection to more than one year after the clearance of the virus. The patient's IgH repertoire 14 and 64 days after symptom onset showed dramatic dominant clonal expansion but low clonal diversity. IgH repertoire 6 months after disease-free status had few dominant clones but increased diversity. E-binding antibodies appeared abundantly in the repertoire during the early stages of infection but quickly declined after clearance of the virus. Certain VH genes such as VH5-10-1 and VH4-39 appeared to be preferentially enlisted for a rapid antibody response to ZIKV infection. Most of these antibodies require relatively few somatic hypermutations to acquire the ability to bind to the E protein, pointing to a possible mechanism for rapid defence against ZIKV infection. This study provides a unique and holistic view of the dynamic changes and characteristics of the antibody response to ZIKV infection.

5.
Chemosphere ; 247: 125861, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31931317

RESUMO

In this study, the seasonal mean PM2.5 concentration in Qingdao, a coastal city, during 2014-2018 was first analyzed and the winter, in particular of 2015, showed the highest concentration. To elucidate the sources and control factors of PM2.5, three dimensional model Weather Research and Forecasting (WRF), Community Multiscale Air Quality model (CMAQ), as well as Flexible Particle model (FLEXPART), were used. During December 2015 and January 2016, modeling results showed that the mean contribution to PM2.5 mass concentrations from local emissions in Qingdao was 25%, and the transport from north and west accounted for almost half. Over the two episodically polluted periods (29-31 December 2015; 15-17 January 2016), the local emissions in Qingdao surprisingly contributed to only 18% and 24% to PM2.5 mass concentrations, respectively, indicating the dominant contributions from other regions, such as areas outside Qingdao in Shandong and Beijing-Tianjin-Hebei (BTH). The results show the sources region and contribution may vary remarkably along with the change in the pathways of the air parcel, inferred by the FLEXPART, while the near-surface PM2.5 enhancement is largely caused by downward vertical advection and enhanced aerosol chemistry reactions, accompanied by simultaneous drop in the boundary layer height. This study also reveals that the transport contribution is sensitive to the air parcel trajectories. We, therefore, recommend the efficient emission control based on transport trajectories in short-term air quality improvement in Qingdao.

6.
Environ Technol ; 41(4): 478-487, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30016186

RESUMO

The accumulation of multi-hydrolytic enzyme through anaerobic co-digestion of waste-activated sludge (WAS) and food waste (FW) was studied by regulating temperature, pH and the mass ratio of FW to WAS (F/W). Experimental results showed that temperature had a profound effect on the activity of the enzyme and the most suitable temperatures for the accumulation of amylase and protease were 37°C and 50°C, respectively. The highest activity of amylase and protease accumulated reached 10.29 and 19.23 U/mL at an F/W ratio of 2:1. The addition of anaerobic co-digestion solution enriching protease and amylase had positive effects on the hydrolysis of WAS. In addition, the Illumina high-throughput sequencing demonstrated that the bacterial diversity decreased, but the bacterial abundance increased during the co-digestion process of WAS and FW. The predominant strains for secreting amylase were Lactobacillus and Clostridium-sensu-strito-1, and Aeromonas was the dominant strain for secreting protease.


Assuntos
Microbiota , Eliminação de Resíduos , Anaerobiose , Reatores Biológicos , Alimentos , Hidrólise , Metano , Esgotos
7.
Sci Total Environ ; 707: 135656, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-31780151

RESUMO

A stability-enhanced magnetic catalyst, composed of α-Fe2O3@Fe3O4 shell-core magnetic nanoparticles and graphene oxide (MGO), was prepared and characterized by scanning electron micrope (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). Catalyst synthesis was used to efficiently activate persulfate for the removal of 2,4-dichlorophenol (2,4-DCP). A magnetic nanoparticle:GO mass ratio of 5 (MGO-5) exhibited a better catalytic efficiency and could be effectively reused four times. The influences of the pollutant, catalyst, and oxidant concentrations were investigated, and the intrinsic relationships among these factors and the degradation kinetic constant were evaluated by a fitting method. It was found that the catalytic degradation process in the MGO-5-persulfate-2,4-DCP system was most likely dominated by an interfacial catalytic reaction, with an activation energy of 13.88 kJ/mol. Radical quenching experiments and electron paramagnetic resonance (EPR) analysis indicated that both sulfate radicals (SO4-) and hydroxyl radicals (OH) were responsible for 2,4-DCP removal, but surface-bounded SO4- played a greater role. Chloride ions at a concentration of 0-60 mg/L had no effect on 2,4-DCP removal. The proposed advanced oxidation technology has potential applications for the practical removal of aqueous organic pollutants.

8.
Phys Chem Chem Phys ; 22(2): 489-496, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31822871

RESUMO

In this paper, three novel metallic sp2/sp3-hybridized boron nitride (BN) polymorphs are proposed by first-principles calculations. One of them, denoted as tP-BN, is predicted based on the evolutionary particle swarm structural search. tP-BN is composed of two interlocked rings forming a tube-like 3D network. The stability and band structure calculations show that tP-BN is metastable and metallic at zero pressure. Calculations for the density of states and electron orbitals confirm that the metallicity originates from the sp2-hybridized B and N atoms, forming 1D linear conductive channels in the 3D network. According to the relationship between the atomic structure and electronic properties, another two 3D metastable metallic sp2/sp3-hybridized BN structures are constructed manually. Electronic property calculations show that both of these structures have 1D conductive channels along different axes. The polymorphs predicted in this study enrich the structures and provide a different picture of the conductive mechanism of BN compounds.

9.
J Biomech ; 99: 109478, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31706561

RESUMO

The inadequate landing zone during thoracic endovascular aortic repair (TEVAR) could be resolved by fenestration technology. The fenestration structure consists of a main endograft and a left subclavian artery (LSA) stent-graft. The purpose of this study is to assess the biomechanical implications of the protruding segment (PS) of the LSA stent-graft after TEVAR with in situ fenestration (ISF-TEVAR). The PS is characterized by the protruding length and centerline angle between the LSA and PS. An idealized three-dimensional geometric model of the human aorta was constructed as the reference benchmark. We designed nine postoperative aortic geometries with different protruding lengths (5, 10, 15 mm) and centerline angles (-20°, 0°, +20°). The blood was assumed to be non-Newtonian and the three-element Windkessel model was applied to reproduce physiological pressure waveforms. The interaction between the blood and vessel wall was captured by a two-way fluid-structure method. We also considered the impact of the fenestration structure on the vessel wall. Long protruding length (15 mm) and the retrograde angle (+20°) result in a markedly reduced LSA flow ratio (1.3%). There is a pressure difference between the inner and outer walls of the PS. The region around the PS is more prone to thrombosis. The flow stability and turbulence intensity of downstream blood of the PS gradually deteriorate. The largest deformed region moves from the aortic arch to the ascending aorta after ISF-TEVAR. The postoperative hemodynamics largely depends on the protruding length and angle of the LSA stent-graft. The configurations should be carefully controlled during ISF-TEVAR.

10.
Med Eng Phys ; 76: 32-39, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31882394

RESUMO

The aortic major branches after thoracic endovascular aortic repair (TEVAR) could be preserved by in situ fenestration (ISF). This study aims to explore the hemodynamic consequences of ISF-TEVAR with double fenestrations. Two patients with aortic dissection and aneurysm, respectively, were treated by ISF-TEVAR and both the left carotid artery (LCA) and left subclavian artery (LSA) were reconstructed by fenestration technique. The blood was considered a non-Newtonian fluid and the Windkessel model was adopted at the aortic outlets. Simulations were performed in two postoperative models to analyze the effects of the double fenestration stents on the hemodynamics. The postoperative wall pressure of the LCA and LSA is relatively low and the pressure difference between the inner and outer walls of the protruding segment of the LSA stent is found. Acceleration occurs when blood flows around the fenestration stents and the shear-thinning rheological behavior is observed at the aortic arch. Moreover, regions susceptible to thrombosis are identified and the surface exposed to high relative residence time is located at the aortic arch after the LSA stent. The presence of the double fenestration stents has a profound impact on the postoperative hemodynamics, and the aortic arch and rebuilt branches should be closely watched during follow-up.

11.
Nanotechnology ; 31(10): 105205, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31766025

RESUMO

We investigate theoretically the anisotropic electronic and optical behaviors of a monolayer black phosphorus (phosphorene) modulated by periodic potential superlattices in arbitrary directions. We demonstrate that different strength and orientation of the phosphorene potential superlattice can give rise to distinct energy spectra, i.e. tuning the intrinsic electronic anisotropy. Accordingly, the anisotropic effective mass, and optical absorption modulated by superlattice strength and orientation are addressed systematically. This feature enables tuning capability more than one order of magnitude in the optical absorption spectrum. Our findings should be useful in building phosphorene optical and (opto)electronic devices by applying external potential superlattice.

12.
Biosystems ; 185: 104033, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31541672

RESUMO

Nucleosome occupancy changes across cell types and environmental conditions and such changes often have profound influence in transcription. It's of importance to identify the differential nucleosome regions (DNRs) where the nucleosome occupancy level differs across cell types. Here we developed DNMHMM, a Hidden Markov Model (HMM) based algorithm, to detect the DNRs with nucleosomal DNA sequenced dataset. The performance evaluation indicates that DNMHMM is advisable for multi-cell type comparison. Upon testing this model in yeast mutants, where the modifiable histone residues were mutated into alanine, we found that DNA sequences of the dynamic nucleosomes lack 10-11 bp periodicities and harbor binding motifs of the nucleosome remodelling complex. Moreover, the highly expressed genes have more dynamic nucleosomes at promoters. We further compared nucleosome occupancy between resting and activated human CD4+ T cells with this model. It was revealed that during the activation of CD4+ T cells, dynamic nucleosomes are enriched at regulatory sites, hence, up to some extent can affect the gene expression level. Taken together, DNMHMM offers the possibility to access precise nucleosome dynamics among multiple cell types and also can describe the closer association between nucleosome and transcription.

13.
Environ Sci Pollut Res Int ; 26(32): 32764-32776, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31512124

RESUMO

The activation of persulfate to produce active radicals has been attracting wide attention in environmental remediation fields. Among various catalysts, non-metal carbocatalysts and carbon-based composites have shown attractive prospects given that they are environmental-friendly, highly efficient, abundant, and diverse. In this paper, the use of carbon-based magnetic nanocomposites as catalysts for persulfate activation was reviewed and discussed. The preparation methods of carbon-based magnetic nanocomposites were first briefly summarized. Subsequently, the use of activated carbon, carbon nanotubes, graphene oxide, biochar, and nanodiamond-based magnetic composites to activate persulfate was discussed, respectively. A synergetic effect between carbon materials and magnetic nanoparticles facilitated the activation process because of the increased electron transfer capacity, good dispersity of magnetic nanoparticles, and good repeatability and separability. Both radical and non-radical pathways were detected in the activation processes, but the specific mechanisms were greatly influenced by the components of the catalyst and solution conditions. And fundamental studies were needed to clarify the inner mechanisms of the process. In the end, strategies for enhancing the catalytic performances of carbon-based magnetic nanocomposites were suggested. It is expected that this review will provide some inspirations for developing highly efficient and green catalyst, as well as sulfate radical-based advanced oxidation technology for the remediation water environment.

14.
Ecotoxicol Environ Saf ; 184: 109656, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31526920

RESUMO

The existing form of ionizable organic contaminants (IOCs) could affect their adsorption characteristics to soil and biochar. In this study, 2 IOCs, namely, sulfadiazine and imazalil, were selected to study their adsorption by rice straw-derived biochar-amended soils, as well as the effect of pH and gallic acid on their adsorption. The results showed that the soil adsorption isotherms of the two ionizable organic contaminants could be fitted well by a linear equation and the Freundlich equation, and r2 was more than 0.80. The adsorption coefficient (Kd) in the three kinds of soil ranged from 0.262 to 4.07 L kg-1 for sulfadiazine and from 3.11 to 96.5 L kg-1 for imazalil. After the addition of biochar, the adsorption of sulfadiazine and imazalil in the soil increased. The adsorption of sulfadiazine by biochar gradually decreased with the increase in pH; the adsorption of imazalil increased when the pH increased from 2 to 5 and then gradually decreased with increasing pH. Gallic acid enhanced the adsorption of the two IOCs to pure soil and biochar-amended soil.


Assuntos
Carvão Vegetal/química , Ácido Gálico/química , Oryza/química , Poluentes do Solo/análise , Solo/química , Adsorção , Concentração de Íons de Hidrogênio , Imidazóis/análise , Sulfadiazina/análise
15.
Phytomedicine ; 64: 153072, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31480012

RESUMO

BACKGROUND: Breast cancer is one of the most lethal cancers in women when it reaches the metastatic stage. The plant Carpesium cernuum has been used as an anti-inflammatory, analgesic, and detoxifying agent in Chinese folk medicine. However, the inhibitory activity and molecular mechanisms of Carpesium cernuum in breast cancer cells have not been investigated. METHODS: RNA sequencing experiments were performed to elucidate the cellular pathways affected by Carpesium cernuum extract (CCE). Cell viability and EdU incorporation assays were conducted to determine the effect of CCE on cell proliferation. The inhibitory effects of CCE on the expression levels of target genes were confirmed by qRT-PCR and Western blot. Cell migration and invasion were analysed with transwell chamber assays. RESULTS: Proliferation assays indicated that CCE inhibited cell proliferation in multiple cancer cell lines and the IC50 value of CCE was the smallest in MDA-MB-231 cells. Transcriptome analysis showed that CCE significantly affected the cell adhesion pathway. Further experiments revealed that CCE suppressed cell migration and invasion. The inhibitory effect on migration was likely mediated by targeting TIMP1, MMP9, CD44 and COL4A2. The main active components of CCE were isolated, and CCE-derived sesquiterpene lactone substances could reproduce the inhibitory effect of CCE on cell migration and invasion. CONCLUSIONS: Overall, both molecular and phenotypic assays showed that CCE has potential in the treatment of breast cancer, especially for the treatment of breast cancer metastasis. CCE-derived sesquiterpene lactone substances are the foundation for the tumor inhibitory effect of CCE.

16.
PLoS One ; 14(8): e0218379, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31404067

RESUMO

A multi-trait selective breeding program of Macrobrachium rosenbergii was initiated in China in 2015. In this program, the M. rosenbergii resources were widely collected from four countries, the origin of the founders was verified with 16 microsatellites and the pedigree was reconstructed, and the optimum contribution selection was used to make the mating design. In this study, we evaluated the genetic parameters and selection response for the harvest body weight (HBW) of M. rosenbergii after being communally reared for 95-109 days. The data were collected from two generations that comprised 25,212 progenies from 150 sires and 198 dams. The residual maximum-likelihood methodology was employed to evaluate the variance components, by fitting an animal model. The accuracy of estimated breeding values increased by 0.38% after pedigree reconstruction using microsatellite markers. The estimated heritability (h2) for HBW was moderate (0.212 ± 0.049) and the common environmental coefficient (c2) was low (0.063 ± 0.017) when all the data were used for the analysis. Within generations, h2 was moderate to high (0.198 ± 0.080 to 0.338 ± 0.049). c2 could only be estimated in G1, which was 0.055 ± 0.030. The average HBW of males was significantly larger than that of females (P < 0.01). h2 estimated for female HBWs were higher than that for males within generations, while h2 estimated for female HBWs were lower than that for males across generations. But they were not significantly different (P > 0.05). The genetic correlations between sexes were moderate to high within each generation (0.529 to 0.763). Two methods were used to estimate the realized response. One method was calculated from the differences between the least squares means of the selected population HBW and that of control population HBW, which was 14.01%. The other method was calculated from the differences between the EBVs of the selected population HBW and that of control population HBW, which was 11.52%. The predicted responses derived from two sets of genetic parameters acquired from within- and across- generation datasets were 11.68% and 10.67%, respectively. The present study provides valuable information for breeding programs of M. rosenbergii.

17.
J Cancer ; 10(15): 3420-3426, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31293645

RESUMO

Precision medicine is emphasizing not only at individual but also at disease molecule level in modern medicine. Therefore, target-specific molecular agents are crucial for precise diagnosis and treatment. We developed a peptide agent that binds a critical chemokine receptor-CXCR4 and could be used to detect tumor status. Confocal images showed binding of the peptide agent to human osteosarcoma cells. Clinical gold-standard molecular imaging agent PET showed tumors had high glucose metabolism, CT showed that these xenograft tumors were calcified and displayed hypervascularity. Peptide imaging demonstrated that these tumors were CXCR4 positive. However, Western blot protein analysis revealed a discordance between the tumor and the CXCR4 targeted agent, suggesting that small changes in peptide sequences have profound effect on binding to their targets. We also demonstrated the molecular screening by modifying the peptide sequence and thereby altering the binding properties of the agent. In conclusion, this study demonstrates that small molecule peptide agents can be used as an additional diagnostic tool for precision medicine.

18.
Bioresour Technol ; 288: 121541, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31150970

RESUMO

Chemical constituents are important properties for utilization of biomass, and experimental approaches are always expensive and time-consuming to determinate those properties. Here, a novel random forest (RF) model is developed for accurately predicting biomass major chemical constituents from the much-easier available ultimate analysis, and compared with the previous correlation as well as the experimental data. Two databases are constructed for training and application of the RF model from available literature. The training results show that the determination coefficients (R2) of the RF model predictions are 0.954, 0.933 and 0.968 for cellulose, hemicellulose and lignin, respectively. The application results show that the present RF model can give accurate predictions on chemical constituents for various biomasses with MAPE<20%, and R2 are 0.862, 0.904 and 0.962 for predictions of cellulose, hemicellulose and lignin, respectively. While the previous correlation only works for a narrow range used to develop the correlation, and gives unrealistic negative predictions with MAPE>500% for outside samples.


Assuntos
Celulose , Lignina , Biomassa , Polissacarídeos
19.
Chemosphere ; 231: 495-501, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31151009

RESUMO

Humic acid (HA) is ubiquitous in the environment, and its effect on the adsorption of pollutants onto biochar (BC) has been widely investigated. However, the catalytic degradation of organic contaminants induced by persistent free radicals (PFRs) in BC is not negligible. In this study, two different source of external HA, dissolved HA and coated HA, was employed to assess the effect of HA on the degradation of organic contaminant ciprofloxacin (CIP) by PFRs in BC. Results showed that relatively low concentration of dissolved HA promoted the removal of CIP from 59.78% (control) to 66.70% (5 mg/L dissolved HA) by BC, but higher concentration of dissolved HA inhibited. By contrast, coated HA altered the characteristics of BC and had negative impact on organics removal. The removal of CIP by BC in the presence of HA did not have a great difference at pH 6-9, and increasing dissolved oxygen promoted CIP degradation. In addition, the contribution of CIP removal led by adsorption was 47.61%, 41.62% and 47.84% respectively for BC, BC + dissolved HA and 1% HA coated BC. Correspondingly, the contribution of CIP removal led by •OH induced from PFRs in BC was respectively 21.88%, 35.58% and 25.11%, and the contribution led by PFRs themselves oxidation was 30.51%, 22.80% and 27.05%, respectively. The calculated contributions of adsorption and degradation to CIP removal demonstrated that the contribution of degradation to CIP removal led by •OH increased, while the contribution led by PFRs themselves oxidation was inhibited in the presence of dissolved and coated HA.


Assuntos
Carvão Vegetal/química , Ciprofloxacino/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Ciprofloxacino/química , Substâncias Húmicas , Oxirredução , Esgotos , Poluentes Químicos da Água/análise
20.
Nanotechnology ; 30(34): 345203, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31108474

RESUMO

In two-dimensional layered materials, layer number and stacking order have strong effects on the optical and electronic properties. Tungsten disulfide (WS2) crystal, as one important member among transition metal dichalcogenides, has been usually prepared in a layered 2H prototype structure with space group P63/mmc ([Formula: see text]) in spite of many other expected ones such as 3R. Here, we report simultaneous growth of 2H and 3R stacked multilayer (ML) WS2 crystals in large scale by chemical vapor deposition and effects of layer number and stacking order on optical and electronic properties. As revealed in Raman and photoluminescence (PL) measurements, with an increase in layer number, 2H and 3R stacked ML WS2 crystals show similar variation of PL and Raman peaks in position and intensity. Compared to 2H stacked ML WS2, however, 3R stacked one always exhibits the larger red (blue) shift of Raman [Formula: see text] (A1g) peak and the appearance of PL A, B and I peaks at lower energies. Thereby, PL and Raman features depend on not only layer number but also stacking order. In addition, circularly polarized luminescence from two prototype WS2 crystals under circularly polarized excitation has also been investigated, showing obvious spin or valley polarization of these CVD-grown multilayer WS2 crystals.

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