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1.
Sci Rep ; 10(1): 4020, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32132573

RESUMO

The explore-exploit dilemma describes the trade off that occurs any time we must choose between exploring unknown options and exploiting options we know well. Implicit in this trade off is how we value future rewards - exploiting is usually better in the short term, but in the longer term the benefits of exploration can be huge. Thus, in theory there should be a tight connection between how much people value future rewards, i.e. how much they discount future rewards relative to immediate rewards, and how likely they are to explore, with less 'temporal discounting' associated with more exploration. By measuring individual differences in temporal discounting and correlating them with explore-exploit behavior, we tested whether this theoretical prediction holds in practice. We used the 27-item Delay-Discounting Questionnaire to estimate temporal discounting and the Horizon Task to quantify two strategies of explore-exploit behavior: directed exploration, where information drives exploration by choice, and random exploration, where behavioral variability drives exploration by chance. We find a clear correlation between temporal discounting and directed exploration, with more temporal discounting leading to less directed exploration. Conversely, we find no relationship between temporal discounting and random exploration. Unexpectedly, we find that the relationship with directed exploration appears to be driven by a correlation between temporal discounting and uncertainty seeking at short time horizons, rather than information seeking at long horizons. Taken together our results suggest a nuanced relationship between temporal discounting and explore-exploit behavior that may be mediated by multiple factors.

2.
Nanoscale ; 2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-32215408

RESUMO

A novel composite nanomaterial is prepared by growing small Au nanoparticles on two-dimensional covalent organic framework nanosheets (Au NPs/COF NSs). The synthesized hybrid nanosheets are used as a new platform for multiplexed detection of hepatitis A virus DNA (HAV) and hepatitis B virus DNA (HBV). Additionally, this sensing platform based on Au NPs/COF NSs can be used as a candidate for monitoring the distribution of potassium ions (K+) and the intracellular K+ level in living cells. Accordingly, the sensing systems based on hybrid Au NPs/COF NSs have shown great potential for the investigation of biomolecules and related biological applications.

3.
ACS Sens ; 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32159349

RESUMO

5-Formylcytosine (5fC) is a rare base found in mammalian DNA, which is thought to be involved in the demethylation of DNA. As a stable epigenetic modification, 5fC participates in gene regulation and cell differentiation, and plays an important role in the growth and development of plants. However, the abundance of 5fC is only as low as 0.002-0.02% of cytosine. Therefore, to further understand the functions of 5fC, a rapid, highly sensitive, and efficient method is needed for detecting 5fC. Herein, a novel photoelectrochemical (PEC) biosensor was constructed for 5fC detection, where a MoS2/WS2 nanosheet heterojunction was employed as a photoactive material, amino-functionalized Fe3O4 and SMCC were used as a linker, 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole was adopted as 5fC recognition reagent, and black TiO2 (B-TiO2) was used as a signal amplification unit. Under the optimal experimental conditions, this PEC biosensor showed a wide linear range of 0.01-200 nM and a low detection limit of 2.7 pM (S/N = 3). Due to the specific covalent reaction between -NH2 and -CHO, the biosensor presented high detection sensitivity, even discriminating 5fC with 5-methylcytosine and 5-hydroxymethylcytosine. The biosensor was then applied to investigate the effect of heavy metal Cd2+ on 5fC content in the root, stem, and leaves of maize seedlings.

4.
Mater Sci Eng C Mater Biol Appl ; 110: 110624, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32204066

RESUMO

There has been a recent increase in research interest regarding the development of wound dressings containing bioactive compounds capable of improving outcomes for complex healing needs. In the present study, we describe the generation of bromelain immobilized eletrospun poly(ε-caprolactone) (PCL) fibers (BrPDA-PCL fibers) using the dopamine-assisted co-deposition strategy. We wanted to combine the structural advantage of electrospun fiber and the activity of bromelain and PDA to develop functional wound dressings. We found that bromelain activity could be better stabilized when via its immobilization on electrospun fibers. The resultant BrPDA-PCL fibers exhibited promising properties including optimal mechanical stability, wettability, and rates of water vapor transmission. In addition, these BrPDA-PCL fibers were biocompatible, allowing for effective cellular adhesion and proliferation. The results of zone of inhibition testing further confirmed that these fibers achieved effective antibacterial activity against Escherichia coli and Staphylococcus aureus. When used in vivo, as compared with PCL fibers or control animals the BrPDA-PCL fibers enhanced wound healing rates while reducing associated inflammation. As such, these results indicate that these biocompatible BrPDA-PCL fibers exhibit desirable physicochemical properties making them ideal for use as a wound dressing to enhance the repair of full-thickness wounds to the skin.

5.
Chem Biodivers ; 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32212241

RESUMO

Three new indole diketopiperazine alkaloids, 11-methylneoechinulin E ( 1 ) and variecolorin M ( 2 ), and (+)-Variecolorin G ( 3a ), along with 12 known analogues ( 3b - 14 ), were isolated from a soft coral-associated epiphytic fungus Aspergillus sp. EGF 15-0-3. The structures of the new compounds were unambiguously established by extensive spectroscopic analyses including HRESIMS, 1D and 2D NMR spectroscopy and optical rotation measurements. The absolute configurations of 3a and 3b were determined by experimental and quantum-chemical ECD investigations and single- crystal X-ray diffraction analysis. 3 is a pair of enantiomeric mixtures with a ratio of 1:2. Moreover, 9 is firstly reported as a natural product. The cytotoxic activities of all the isolated compounds against NCI-H1975 gefitinib resistance (NCI-H1975/GR) cell lines were preliminarily evaluated by MTT method.

6.
Ultrason Sonochem ; : 105054, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32173184

RESUMO

In order to explore the potential application of combined physical treatment in producing highly lipophilic modified starch, the effects of ultrasound combined with freeze-thaw treatment on the microstructure and physicochemical properties of potato starch were investigated. The samples treated by combined treatment had the roughest structure and the oil adsorptive capacity value increased from 59.62% (native starch, NS) to 80.2% (7 cycles of ultrasound-freeze-thaw treatment starch, 7UT-FTS). Compared to NS, the crystalline type and chemical groups of modified starches did not change, but the relative crystallinity, enthalpy change, and paste viscosity decreased to varying degrees, while the gelatinization temperature increased. The digestibility of raw modified starch was higher than that of NS, but this phenomenon disappeared after gelatinization. 7UT-FTS showed better resist-digestibility than NS after encapsulating oil. Hence, this would be an efficient and environmentally friendly way to produce modified starch with safety, highly lipophilic and heat resistance.

7.
Sci Rep ; 10(1): 4241, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144317

RESUMO

The real-time monitoring technology plays a significant role in the field of laser aided manufacturing. It not only ensures the product quality, but also saves time and expenditure on the subsequent testing. To develop a method to monitor the properties of laser molten zone, in this paper, the AISI4140 steel samples were melted by laser with different parameters. At the same time, the plasma spectra were detected during real-time laser processing. The evolutions for both emission spectra and hardness of molten zone were researched in this work. To correlate the intensity of spectral line with the hardness of molten zone, the method of dimensionless analysis was used in this experiment. As the results shown, in a dimensionless system, there was a linear correlation between dimensionless micro-hardness of molten zone (H*) and dimensionless laser energy density(ln(δ*)); the dimensionless micro-hardness could be expressed by a piecewise function using dimensionless intensity of Fe I spectral lines(I*), dimensionless velocity(v*) and dimensionless laser energy density as variables; depending on the quantitative relation among all dimensionless, a monitoring system of hardness of molten zone was established; by testing under different parameters of laser processing, the mean error of prediction is lower than 3.1%. It means the emission spectroscopy can be a potential way to monitor the properties of parts prepared by laser processing.

8.
Brain Behav ; : e01573, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32073739

RESUMO

INTRODUCTION: Triggering receptor expressed on myeloid cells-like transcript 2 gene (TREML2) is a newly identified AD susceptibility gene. Its missense variant rs3747742-C substantially decreases AD risk in both Caucasians and Han Chinese, but the underlying mechanisms remain elusive. In the present study, to uncover the possible mechanisms by which TREML2 rs3747742-C reduces AD risk, we investigated the possible relation of this variant with AD-related brain structures using a cognitively normal elderly population from Alzheimer's Disease Neuroimaging Initiative (ADNI) database. METHODS: In total, 158 cognitively normal elders from ADNI database with complete data for brain structures and TREML2 rs3747742 genotype were included in this study. The association of TREML2 rs3747742 genotype with the structures of three cerebral cortices (entorhinal cortex, middle temporal gyrus, and parahippocampal gyrus), two subcortical regions (amygdala and hippocampus), and three subfields of hippocampus (CA1, CA2 + CA3, and CA4 + dentate gyrus) was investigated. RESULTS: A significant difference was noted in the volume of right CA1 subfield among three genotypes of TREML2 rs3747742 (p = .0364). In the multivariate analysis, TREML2 rs3747742-C significantly increased right CA1 subfield volume after adjusting for age, gender, education years, APOE ε4 status, and intracranial volume under the recessive genetic model (Bonferroni corrected p = .003586). CONCLUSION: The present study provides the first evidence that TREML2 rs3747742-C carriers have larger volumes of hippocampal CA1 subfield in a cognitively normal elderly population. These findings imply that enhancement of brain reserve may contribute to the protection of TREML2 rs3747742-C in AD susceptibility.

9.
J Hazard Mater ; 392: 122314, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32092651

RESUMO

A self-made microporous molecular sieve CS-Z1 has been found to have excellent adsorption performance for small molecular nitrile and pyridine pollutants in acrylonitrile production wastewater. In order to explore its adsorption mechanism, the adsorption kinetics, isotherms and thermodynamics of CS-Z1 for eight nitrile and pyridine organic pollutants with different structures and properties were investigated. Meanwhile, the analysis of molecular dynamics simulation based on density functional theory was conducted to revel the adsorption-diffusion process of different organic pollutants on the surface and in the pores of CS-Z1. Both the experimental and simulated results verified the shape-selective adsorption mechanism of CS-Z1 for these organic pollutants. The adsorption processes of CS-Z1 for these pollutants were spontaneous physical adsorption, and the adsorption efficiency of CS-Z1 mainly depended on the molecular size of pollutant. Benefitting from the flexible crystalline structure of CS-Z1 and the breathing vibration of CS-Z1 orifices, it could adsorb some pollutants with slightly larger size than its pore diameter. Molecular dynamics simulation results visually display the shape-selective adsorption process of CS-Z1 for these pollutants through the respiratory effect of CS-Z1 molecular sieve orifices.

10.
Cryobiology ; 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32044324

RESUMO

The purpose of this present study is to assess if addition of the synthetic polymers in maturation medium can influence cryotolerance and subsequently embryonic development of mammalian oocytes. We examined the roles of two polymers, including polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), on in vitro maturation (IVM), embryonic developmental capacity, and cryotolerance of goat oocytes. The present study includes two parts. At first, goat cumulus-oocyte complexes (COCs) were matured in a medium supplemented with 10% fetal bovine serum (FBS), 3 mg/ml PVP, or 1 mg/ml PVA, respectively. Data of oocyte with first polar body, cleavage, and blastocyst following parthenogenetic activation (PA) were recorded. Secondly, after maturation in the above medium, oocytes were vitrified using the Cryotop technique and then the morphology, cleavage and blastocyst formation of vitrified oocytes have been checked. The results demonstrated that the adding of PVP or PVA in maturation medium can't affect IVM of goat oocytes in comparison with FBS, as concern cumulus cell expansion, first polar body formation, and embryonic development. Additionally, without plunging into liquid nitrogen, only exposure to the vitrification and warming solutions cannot also influence the quality of oocytes, in terms of morphology, cleavage, and blastocyst formation. However, after IVM with synthetic polymers and vitrification, the ratio of oocytes with standard morphology in PVP or PVA group was only 59.47% ±â€¯3.56% or 54.86% ±â€¯5.19%, respectively, and was significantly less than that in the FBS group (89.37% ±â€¯4.52%, P < 0.05). Furthermore, the cleavage ratio of oocytes in PVP or PVA group was 37.41% ±â€¯4.17% or 27.71% ±â€¯3.91% and was considerably less than that in the FBS group (64.97% ±â€¯4.69%, P < 0.05). In addition, the cleavage ratio in PVP group was statistically higher than that in PVA group (P < 0.05). In terms of blastocyst development, a significant difference was observed between the synthetic polymer group and the FBS group (24.96% ±â€¯3.62%, P < 0.05). However, the blastocyst ratio in the PVA group (7.51% ±â€¯1.68%) was statistically less than the PVP groups (13.20% ±â€¯4.59%, P < 0.05) and the FBS group (P < 0.05). In conclusion, two potential serum replacements, either PVP or PVA, can support IVM and embryonic development of goat oocytes at the concentration used in this study. But IVM with synthetic polymers supplemented to maturation medium may reduce the cryotolerance of oocytes. Additionally, the supportive function of PVP on embryonic development of vitrified oocytes might be better than that of PVA.

11.
Eur J Pharm Sci ; 145: 105241, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001345

RESUMO

Cancer-associated thrombus (CAT) impedes delivery of nanoparticles to tumor sites and also inhibits the ability of immune cells to detect and attack these tumors, particularly in advanced tumors with old thrombi. Nattokinase (NK) is an extract from a popular Japanese food, natto, which consists of boiled soybeans fermented with bacteria. Nattokinase exerts strong fibrinolytic and thrombolytic activities and can unblock blood vessels. To deliver NK to thrombus sites in tumors, we modified the surface of NK with polysialic acid (PSA), which formed complexes via electrostatic interactions, resulting in NK-PSA. Particle size and zeta potential of NK-PSA were evaluated, and differential scanning calorimetry, Fourier-transform infrared spectroscopy, and morphological analyses of NK-PSA were performed. To determine the efficacy of the NK-PSA complex on delivery of nanoparticulate drugs, sialic acid-modified doxorubicin liposomes (DOX-SAL) were used as a model drug. In vivo pharmacokinetic and tissue distribution analyses showed that the blood clearance rate of DOX-SAL was significantly enhanced by NK-PSA, and NK-PSA increased accumulation of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR) labeled SAL (DiR-SAL) in tumors. Analysis of anti-tumor efficacy showed that the combination of NK-PSA and DOX-SAL enhanced anti-tumor activity. These results suggested that NK-PSA combined with DOX-SAL may be an effective strategy to clear CAT and increase the ability of nanoparticles and immune cells to reach tumors.

12.
Nanoscale ; 12(5): 3273-3283, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31971202

RESUMO

The structures, compositions and chemical states of metal catalysts are prone to dynamic changes in response to reaction conditions. In this work, a combination of in situ X-ray absorption fine structure spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy has been used to monitor the temperature-dependent structural dynamics in bimetallic Pt-Co(OH)2 nanocatalysts during CO oxidation. Alloying with electron-donating Co promotes the catalytic activity of metallic Pt for CO oxidation at low temperature. At elevated temperatures under an oxidation atmosphere, O2 drives the segregation of the Pt-Co alloy into cobalt oxide and platinum metal, with the extent of alloying sharply decreasing from ∼30% at 300 K to 0 at 473 K. Reduction at high temperature could recover the formation of the Pt-Co alloy with the same alloying extent. The observed structural dynamics could be well correlated with the kinetic behavior of the catalysts. This work highlights the importance of tracking the dynamic structural changes of working catalysts for a correct understanding of their catalytic behavior.

13.
Comput Med Imaging Graph ; 80: 101690, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31968286

RESUMO

Fetal echocardiography (FE) is a widely used medical examination for early diagnosis of congenital heart disease (CHD). The apical four-chamber view (A4C) is an important view among early FE images. Accurate segmentation of crucial anatomical structures in the A4C view is a useful and important step for early diagnosis and timely treatment of CHDs. However, it is a challenging task due to several unfavorable factors: (a) artifacts and speckle noise produced by ultrasound imaging. (b) category confusion caused by the similarity of anatomical structures and variations of scanning angles. (c) missing boundaries. In this paper, we propose an end-to-end DW-Net for accurate segmentation of seven important anatomical structures in the A4C view. The network comprises two components: 1) a Dilated Convolutional Chain (DCC) for "gridding issue" reduction, multi-scale contextual information aggregation and accurate localization of cardiac chambers. 2) a W-Net for gaining more precise boundaries and yielding refined segmentation results. Extensive experiments of the proposed method on a dataset of 895 A4C views have demonstrated that DW-Net can achieve good segmentation results, including the Dice Similarity Coefficient (DSC) of 0.827, the Pixel Accuracy (PA) of 0.933, the AUC of 0.990 and it substantially outperformed some well-known segmentation methods. Our work was highly valued by experienced clinicians. The accurate and automatic segmentation of the A4C view using the proposed DW-Net can benefit further extractions of useful clinical indicators in early FE and improve the prenatal diagnostic accuracy and efficiency of CHDs.

14.
J Cell Physiol ; 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31967324

RESUMO

Retention after treatment and effective anchorage control are two essential factors in orthodontics. Our study aimed to explore the effects of fucoidan on orthodontic tooth movement (OTM) and the involvement of macrophages. We established a murine OTM model to test the effect of fucoidan administration. We found that mice injected with fucoidan had a deceleration in OTM and a higher bone mineral density. Moreover, fucoidan increased the proportion of F4/80+ CD206+ macrophages and promoted the messenger RNA expression of Arg-1, CD206, and IL-10 at both in vivo and in vitro levels. In addition, macrophages showed lower expression of TNF-α, IL-1ß, and IL-6 and a decrease in F4/80+ CD11c+ cells. Mechanistically, the level of phosphorylated STAT3 was elevated in unpolarized and restorative macrophages after treatment with fucoidan. Taken together, our findings suggest that fucoidan treatment inhibits OTM and enhances the stability of teeth after movement by promoting restorative macrophages through the STAT3 pathway.

15.
ACS Appl Mater Interfaces ; 12(4): 4463-4472, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31913599

RESUMO

The oxygen reduction reaction (ORR) is an extremely important reaction in many renewable energy-related devices. The sluggish kinetics of the ORR limits the development of many fuel cells. Design and synthesis of highly efficient nonprecious electrocatalysts are of vital importance for electrochemical reduction of oxygen. Herein, we develop a graphitic carbon nitride (g-C3N4)-derived bamboo-like carbon nanotubes/carbon-wrapped Co nanoparticles (BCNT/Co) electrocatalyst by a simple high-temperature pyrolysis and acid-leaching method. The catalytic performance of the as-designed electrocatalyst toward ORR outperforms the commercial Pt/C catalyst in alkaline solution. The onset potential of nonprecious BCNT/Co-800 catalyst was 1.12 V. The half-wave potential was 0.881 V. The result was superior to that of commercial Pt/C (0.827 V vs RHE). The Co nanoparticles, bamboo-like carbon nanotubes, defects, and Co-Nx active sites all result in the remarkable ORR activity, stability, and great methanol tolerance.

16.
Analyst ; 145(4): 1319-1327, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-31942890

RESUMO

Stressed organelles are often challenging to image with canonical organelle probes owing to their propensity to dissipate from stressed organelles. We herein report the imaging of stressed lysosomes with color-switchable glyco-probes that contain an entity of mannose-6-carboxylate or sialic acid for targeting to and long-term retention in stressed lysosomes, and a diad of fluorescein/rhodamine-X-lactam exhibiting dramatic red-to-green fluorescence shift upon pH elevation. Relative to acidotropic dyes prone to dissipate from pH-elevated lysosomes, both glyco-probes are stably trapped in lysosomes without resorting to lysosomal acidity. Importantly, these probes are red emissive in acidic lysosomes (pH 4.5-5.8), but switched to green fluorescence in lysosomes of pH 6.0-7.4, allowing dual color discrimination of lysosomal pH alterations in cell starvation. These results support the use of sugar-armed sensors to investigate stressed lysosomes in biology and disease.

17.
Nanotechnology ; 31(12): 125404, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-31766041

RESUMO

Herein, we design a dual-template-assisted pyrolysis method to prepare ultra-small Fe3O4 nanoparticles anchored on Fe/N-doped hollow porous carbon spheres (0.010-Fe/NHPCS-800) for oxygen reduction reaction (ORR). The synthesized SiO2 nanospheres, which are selected as the hard template, contribute to forming macroporous structure. Pluronic ® F127 is employed to fabricate mesopores through high-temperature pyrolysis as a soft template. In this way, the 0.010-Fe/NHPCS-800 architecture represents an ordered hierarchically porous property with a large BET surface area (1812 m2 g-1), which can facilitate the mass transport of reactants and increase the electrochemically active area. The Fe3O4 nanoparticles wrapped by graphitic carbon layers provide more active sites, and the synergistic interaction between Fe3O4 nanoparticles and doping N has a positive effect on ORR performance. The 0.010-Fe/NHPCS-800 catalyst outperforms the most effective ORR activities among a series of Fe/NHPCS samples with onset potential of 0.95 V (versus reversible hydrogen potential) and half-wave potential of 0.81 V, which is almost the same as the commercial Pt/C (0.96 and 0.81 V, correspondingly) in 0.10 M KOH. However, both the stability and durability of 0.010-Fe/NHPCS-800 surpass those of commercial Pt/C. Given all these advantages, 0.010-Fe/NHPCS-800 is a promising candidate to take the place of Pt-based electrocatalysts for ORR in the future.

18.
J Hazard Mater ; 384: 121417, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31624002

RESUMO

This study describes the successful fabrication of flexible photocatalytic films to remove contaminants from wastewater, the film is comprising sulfuric acid treated graphitic carbon nitride (SA-g-C3N4) embedded within a porous cellulose network (denoted here as CN/CA films). The SA-g-C3N4 content in the films was varied from 0 to 50 wt.%. The sulfuric acid treatment introduced carboxyl and sulfonyl groups on the surface of g-C3N4, which resulted in strong hydrogen bonding with the hydroxyl groups of cellulose acetate (so strong the partial delimination of the SA-g-C3N4 occurred on CN/CA film formation via solvent casting). The obtained films were around 10 µm in thickness, extremely flexible and durable, with the SA-g-C3N4 uniformly distributed throughout the cellulose acetate network. The CN/CA films showed excellent activities for aqueous dye degradation under direct sunlight, as well as outstanding performance for photocatalytic reduction of Cr (VI). The photocatalytic activity of the CN/CA films at the optimum SA-g-C3N4 content of 50 wt.% was far higher than that of pristine SA-g-C3N4, highlighting a main advantage of the composite film fabrication strategy introduced here. Further, the CN/CA films showed excellent stability and reusability, with no loss in activity seen over 5 cycles of dye degradation.

19.
Sci Total Environ ; 704: 135453, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31810675

RESUMO

Ferrous salts have been widely used to enhance phosphorus removal in full-scale wastewater treatment plants, with an average dosage of 0.24-0.35 mM. However, such high dosage inevitably caused serious concerns on operation, potential biological toxicity and excessive sludge production. Thus, this study investigated the effect of micro-dosing of ferrous salt at the level of 0.02 mM on enhanced biological phosphorus removal (EBPR) in sequencing batch reactors. Results showed that micro-dosing of ferrous salt enhanced the overall performance, with average COD, TN and TP removal of more than 4.2%, 2.0% and 5.8%, respectively. In addition, the sequencing analysis further revealed that micro-ferrous dosing could significantly improve the diversity and richness of the microbial community (p < 0.05), whereas the regular dosing of ferrous salts (0.25 mM) negatively impacted on the EBPR performance. It was found that the abundances of phosphorus accumulating organisms (PAOs) in R2 (micro-dosing) were nearly 1.5-fold and 2-fold higher than those in R1 (control) and R3 (regular dosing). The contributions of biological and chemical pathways towards the observed phosphorus removal were also determined according to the phosphorus releasing rate. For micro-dosage and regular dosage of ferrous salts, phosphorus removal mainly relied on biological phosphorus removal and chemical phosphorus removal, respectively. It appears from this this study that the micro-ferrous dosing strategy is practically feasible and economically viable for enhanced phosphorus removal from municipal wastewater.


Assuntos
Fósforo/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Reatores Biológicos , Compostos Ferrosos , Microbiota , Esgotos , Águas Residuárias/química
20.
Sci Total Environ ; 704: 135285, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31822421

RESUMO

Fulvic acid (FA) can serve as electron shuttles between bacteria and electron acceptors. It explored the short-term effect of FA dose on nitrogen removal performance and N-acylated-L-homoserine lactones (AHLs) release change in the anaerobic ammonium oxidation (anammox) system. The results demonstrated that the total inorganic nitrogen removal efficiency increased with the FA dosages from 0.5 mM to 1 mM. FA addition improved anammox bacteria activity, together with extracellular polymeric substances production. FA addition from 0.5 mM to 1 mM stimulated AHLs release in both water and biomass phases, which indicated that the quorum sensing could be improved. These findings revealed that the addition of FA could improve quorum sensing and then enhance nitrogen removal performance.

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