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1.
Chemosphere ; 262: 127886, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32805659

RESUMO

Catalytic oxidation is a promising technique to control the emission of gaseous pollutants. Three-dimensionally ordered macroporous (3DOM)-based catalysts have aroused widespread attention because of their high porosity, large surface area and pore volume, superb ability of mass transfer. Therefore, they have been widely used in gaseous pollutants control field, such as soot and methane catalytic combustion, VOCs catalytic oxidation, photocatalytic CO2 reduction and so on. In this review, the recent studies about the preparation and applications of 3DOM catalysts are summarized. At the same time, the advantages and mechanism of the 3DOM catalysts used in gaseous pollutants control are introduced in depth. Finally, the perspective and future direction of 3DOM-based catalysts for gaseous pollutants control are proposed.


Assuntos
Poluentes Ambientais/química , Catálise , Gases , Metano , Oxirredução , Porosidade , Fuligem
2.
Chemosphere ; : 128856, 2020 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-33189401

RESUMO

Toxicological and epidemiologic evidence has suggested that exposure to disinfection by-products (DBPs) impairs semen quality, while the underlying biological mechanisms remain unclear. This study aimed to examine the mediating role of oxidative stress in association between DBP exposure and semen quality. We measured a urinary biomarker of DBP exposure [trichloroacetic acid (TCAA)] and three urinary biomarkers of oxidative stress [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoPGF2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)] among men from an infertility clinic (n = 299). The associations of oxidative stress biomarkers with urinary TCAA and semen quality were evaluated using multivariable linear regression models, and the mediating role of oxidative stress biomarkers was assessed by a mediation analysis. Urinary TCAA was positively associated with urinary 8-OHdG and 8-isoPGF2α in a dose-response manner (both P for trend < 0.001). Significantly inverse dose-response associations were observed between urinary 8-isoPGF2α and sperm concentration and between urinary 8-OHdG and sperm motility (both P for trend < 0.05). The mediation analysis indicated a significant indirect effect of urinary 8-isoPGF2α in the association between urinary TCAA and decreased sperm concentration (P = 0.01). Our results suggest that lipid peroxidation may be an intermediate mechanism by which DBP exposure impairs semen quality.

3.
J Hazard Mater ; : 124457, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-33189472

RESUMO

Microbial community compositions and functional profiles were analyzed in microcosms established using aquifer materials from a former automobile factory site, where 1,4-dioxane was identified as the primary contaminant of concern. Propane or oxygen biostimulation resulted in limited 1,4-dioxane degradation, which was markedly enhanced with the addition of nutrients, resulting in abundant Mycobacterium and Methyloversatilis taxa and high expressions of propane monooxygenase gene, prmA. In bioaugmented treatments, Pseudonocardia dioxanivorans CB1190 or Rhodococcus ruber ENV425 strains dominated immediately after augmentation and degraded 1,4-dioxane rapidly which was consistent with increased representation of xenobiotic and lipid metabolism-related functions. Although the bioaugmented microbes decreased due to insufficient growth substrates and microbial competition, they did continue to degrade 1,4-dioxane, presumably by indigenous propanotrophic and heterotrophic bacteria, inducing similar community structures across bioaugmentation conditions. In various treatments, functional redundancy acted as buffer capacity to ensure a stable microbiome, drove the restoration of the structure and microbial functions to original levels, and induced the decoupling between basic metabolic functions and taxonomy. The results of this study provided valuable information for design and decision-making for ex-situ bioreactors and in-situ bioremediation applications. A metagenomics-based understanding of the treatment process will enable efficient and accurate adjustments when encountering unexpected issues in bioremediation.

4.
Huan Jing Ke Xue ; 41(11): 5201-5214, 2020 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124265

RESUMO

Olfactory microorganisms mainly include actinomycetes, algae, and myxobacteria, and are widely found in typical water ecosystems such as water source reservoirs, lakes, streams, and oceans. Biologically-derived taste and odor compounds can cause severe off-flavor problems at trace concentrations, threatening the safety of water supplies. Physical and chemical methods have been implemented, but they need to be improved and optimized. Microbial methods show attractive prospects due to their environmentally friendly characteristics. This article reviews the literature regarding the types, biological sources, detection methods, control measures, influencing factors, and odor-producing mechanisms of microbial methods. Future research directions and fields of investigation are discussed in order to promote the related research of taste and odor compounds and ensure the safety of urban water supplies.


Assuntos
Odorantes , Paladar , Ecossistema , Lagos , Abastecimento de Água
5.
J Agric Food Chem ; 68(42): 11726-11734, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-32981311

RESUMO

Anemia is a common chronic kidney disease (CKD) complication contributing to increased morbidity and mortality. Collagen-based traditional Chinese nutraceuticals have long been used in antianemic therapies. This study aims to investigate the therapeutic effectiveness of porcine collagen hydrolysate (CH) and its underlying mechanism in the treatment of renal anemia by using adenine-induced CKD mice, RAW264.7 macrophages, and HepG2 hepatoma cells, with prolyl-hydroxyproline as a reference compound for collagen-derived hydroxyproline-containing di-/tripeptides. CH was found to alleviate renal filtering dysfunction, systemic and kidney inflammation, liver hepcidin overproduction and anemia and to increase erythropoietin production and hypoxia inducible factor (HIF)-2α stability in liver and kidney in CKD mice. Prolyl-hydroxyproline exerted direct anti-inflammatory effects on lipopolysaccharide-activated macrophages and elicited stimulating and inhibiting activities on erythropoietin expression and hepcidin overproduction, respectively, in HepG2 cells by HIF-2α activation. Overall, CH was effective in correcting renal anemia via anti-inflammatory renoprotection and HIF-2α-dependent erythropoietin and hepcidin regulation.

6.
Org Lett ; 22(17): 6822-6826, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32830986

RESUMO

The first total synthesis of gastrodinol, an unprecedented poly-p-cresol-substituted natural product with a rearranged and reconstructed C ring moiety, is reported. Our synthesis features a convergent fragment approach. The Sonogashira coupling reaction forges the two segments together to furnish the conjugated ene-yne. Photocatalytic 6π electrocyclization followed by spontaneous aromatization is used to construct the tetrasubstituted B ring at the late stage. Further study shows that gastrodinol exhibits significant cytotoxic activity against five human cancer cell lines in vitro (IC50 2.5-3.8 µM).

7.
Toxicon ; 186: 168-174, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32828954

RESUMO

Antivenoms are currently the most effective medication used in the treatment of snakebites. However, there were relatively few studies on preparation of antivenoms targeting sea snakes, especially common sea snakes in China. In this study, we sought to prepare and detect mono- and bispecific antisera raised in rabbits against venoms of two sea snakes, Hydrophis cyanocinctus and H. curtus. The results of enzyme-linked immunosorbent assay showed that the rabbit antisera generally showed clearly detectable immunological cross-reactions after the third immunization and indicated that the strength of cross-reactions increased with an increase in the immunizing dose. Proteins within the H. cyanocinctus and H. curtus venoms showed similar profiles and were mainly concentrated in the low-molecular-weight region (8-25 kDa). Western blotting results revealed that the bands of these low-molecular weight proteins were dense and showed strong immunogenicity. Although we detected comparatively few bands of the high-molecular-weight proteins, these also showed strong immunogenicity. Our results indicate that both mono- and bispecific antisera both can neutralize H. cyanocinctus and H. curtus venoms, and in this regard, the monospecific H. curtus and bispecific antiserum were found to be superior to the H. cyanocinctus antiserum. Given the increasing frequency of snakebites worldwide, we believe that the findings of this study will have high practical applicability.


Assuntos
Soros Imunes , Coelhos/fisiologia , Mordeduras de Serpentes , Venenos de Serpentes , Animais , Antivenenos , China , Reações Cruzadas , Venenos Elapídicos , Elapidae , Hydrophiidae
8.
Appl Opt ; 59(20): 6012-6017, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32672743

RESUMO

We propose a microsphere-lens coupler that can successfully constrain the beam with near-field details to achieve ∼100nm lateral resolution accuracy. In theory, we use the finite-difference time-domain method to analyze the properties of the "photonic nanojet." The optimal focusing ability scope can be obtained by adjusting the focusing parameters, such as refractive index, paraxial optical intensity attenuation ratio, sizes of microspheres, and so forth. In experiment, the "non-brush scrubbing" cleaning technology is adopted to optimize the experimental results. Aiming to self-assemble properties of dielectric spheres, we introduce the deagglomeration method to produce homogeneous liquid. Meanwhile, by tiling a 5 µm-diameter microsphere-lens on a specimen, a traditional optical microscope can realize 100 nm lateral superresolution microimaging, which lays a certain foundation for further development of superresolution microimaging.

9.
Huan Jing Ke Xue ; 41(5): 2188-2197, 2020 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608836

RESUMO

Aerobic anoxygenic photosynthesis bacteria (AAPB) play a significant role in the material circulation of the hydrosphere, with diverse community structure and unique metabolic functions. To investigate the spatial and temporal succession characteristics of AAPB abundance and community structure in Jinpen Reservoir, a quantitative real-time polymerase chain reaction and Illumina MiSeq high-throughput sequencing technique targeting the pufM gene were applied. Furthermore, redundancy analysis was used to determine the influence of environmental factors on their community structure. The results showed that the AAPB abundance ranged from (6.70±0.43)×103 to (2.69±0.15)×104 copies·mL-1, with the maximum value appearing in October, and decreased with an increase in water depth. Samples were mainly classified into 19 genera (except for the unclassified genus); the most abundant AAPB genera were Bradyrhizobium sp. and Methylobacterium sp., which were affiliated to the α-Proteobacteria, and the proportion of the Bradyrhizobium sp. was highest in November, accounting for more than 60% (except 10 m). Furthermore, Rubrivivax sp., belonging to ß-Proteobacteria, was found to have a low proportion. There was a strong interaction relationship between AAPB genera. For example, Rhodobacter sp. was positively correlated with Rhodovulum sp., while Hydrogenophaga sp. was negatively correlated with Bradyrhizobium sp.. The community structure composition and distribution of AAPB were significantly different, mainly affected by temperature (T), total nitrogen (TN), NO3--N, and light intensity and comprehensively regulated by environmental factors. For instance, T, TN, and total phosphorus had a significant impact on the AAPB community structure of water samples at 0, 5, and 15 m in October, whereas light intensity, pH, DO, and chlorophyll-a were major structuring factors in the AAPB assemblages of water samples at 5 m in December. The results have guiding significance for parsing the spatial and temporal variability of AAPB abundance and diversity in stratified reservoirs, and simultaneously provide a theoretical basis for exploring the driving factors of AAPB population structure.

10.
Acta Pharmacol Sin ; 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32694760

RESUMO

Oral administration of curcumin has been shown to inhibit pulmonary fibrosis (PF) despite its extremely low bioavailability. In this study, we investigated the mechanisms underlying the anti-PF effect of curcumin in focus on intestinal endocrine. In bleomycin- and SiO2-treated mice, curcumin (75, 150 mg· kg-1 per day) exerted dose-dependent anti-PF effect when administered orally or rectally but not intravenously, implying an intestinal route was involved in the action of curcumin. We speculated that curcumin might promote the generation of gut-derived factors and the latter acted as a mediator subsequently entering the lungs to ameliorate fibrosis. We showed that oral administration of curcumin indeed significantly increased the expression of gut-derived hepatocyte growth factor (HGF) in colon tissues. Furthermore, in bleomycin-treated mice, the upregulated protein level of HGF in lungs by oral curcumin was highly correlated with its anti-PF effect, which was further confirmed by coadministration of c-Met inhibitor SU11274. Curcumin (5-40 µM) dose-dependently increased HGF expression in primary mouse fibroblasts, macrophages, CCD-18Co cells (fibroblast cell line), and RAW264.7 cells (monocyte-macrophage cell line), but not in primary colonic epithelial cells. In CCD-18Co cells and RAW264.7 cells, curcumin dose-dependently activated PPARγ and CREB, whereas PPARγ antagonist GW9662 (1 µM) or cAMP response element (CREB) inhibitor KG-501 (10 µM) significantly decreased the boosting effect of curcumin on HGF expression. Finally, we revealed that curcumin dose-dependently increased the production of 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2) in CCD-18Co cells and RAW264.7 cells, which was a common upstream of the two transcription factors. Moreover, both the in vitro and in vivo effects of curcumin were diminished by coadministration of HPGDS-inhibitor-1, an inhibitor of 15d-PGJ2 generation. Together, curcumin promotes the expression of HGF in colonic fibroblasts and macrophages by activating PPARγ and CREB via an induction of 15d-PGJ2, and the HGF enters the lungs giving rise to an anti-PF effect.

11.
Environ Microbiol ; 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32618113

RESUMO

Thraustochytrium is a unicellular marine protist for the commercial production of very long-chain polyunsaturated fatty acids (VLCPUFAs). Biosynthesis of these VLCPUFAs in the protist is catalysed by a PUFA synthase comprising three subunits, each with multiple catalytic domains. Among these domains, two tandem FabA-like dehydratase domains (DH1 and DH2) in subunit-C together are responsible for introducing double bonds in VLCPUFAs. Domain swapping analysis in yeast showed that the defective phenotype of a Scfas1 mutant could be complemented by expressing an engineered ScFAS1 gene in which the DH domain was replaced by a single DH1 or mutated DH2 of the two. Heterologous expression of the PUFA synthase in E. coli showed that the mutation of DH1 of the two or deletion of DH1 or substitution of DH1 with DH2 resulted in the complete loss of activity in the biosynthesis of VLCPUFAs. Mutation of DH2 of the two or deletion of the DH2 domain produced a small amount of DPA, but not docosahexaenoic acid (DHA). These results indicate that each of the two FabA-like domains of the PUFA synthase possesses distinct function. DH1 domain is essential for the biosynthesis of VLCPUFAs, but DH2 domain is required for the biosynthesis of DHA.

12.
Huan Jing Ke Xue ; 41(7): 3285-3296, 2020 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608902

RESUMO

Phytoplankton and bacteria are important components of the aquatic food web, and play a critical role in substance circulation and energy exchange in freshwater ecosystems. The succession of algae is closely related to the metabolism and structural succession of bacterial populations in the water column. Thus, in this study, the vertical succession characteristics of phytoplankton and bacteria community structure and their coupling with water quality were investigated during an algal bloom in the Lijiahe Reservoir using high-throughput DNA sequencing and Biolog technologies. The results showed that the Lijiahe Reservoir was in the thermal stratification stage in August, and the pH, dissolved oxygen, and NH4+-N of the water column gradually decreased with depth (P<0.001). Algal cell concentration and chlorophyll a exhibited a simultaneous trend (P<0.001), and the maximum values in the surface layer were 3363.33×104 cells·L-1 and 7.03 µg·L-1, respectively. The algal community structure was dominated by Microcystis at water depths of 0 m and 3 m, and at 6 m water depth, Cyclotella replaced Microcystis as the most dominant algae, with a relative abundance of 57.28%. Biolog analysis indicated that the outbreak of Microcystis had a significant impact on bacterial metabolic activity and its relative abundance, but the diversity of bacterial population metabolic activity varied less. A total of 1420 operational taxonomic units were found by high-throughput sequencing, belonging to 10 bacterial phyla. Of these, Actinobacteria and Proteobacteria dominated in all water layers, and their relative abundances were more than 50%. The relative abundance of Chlorobi and Planctomycetes varied significantly with water depth, reaching their maxima at a depth of 6 m with values of 10.29% and 6.78%, respectively, which were both negatively correlated with algal density (P<0.05). Firmicutes and Gemmatimonadetes were positively correlated with algal density (P<0.05). A heat map fingerprint showed that the vertical distribution of the bacterial community structure of the Lijiahe Reservoir varied significantly, and with the increase in water depth, the bacterial community was more uniformly distributed and tended to diversify. Redundancy analysis (RDA) showed that the vertical distribution of the bacterial and algal community structure was regulated by different water qualities, and the difference was significant. This study investigated the coupling mechanism of algal and bacterial communities during the algal bloom in the Lijiahe Reservoir, and the results provided a scientific basis for the investigation of the molecular microecological driving mechanism of water-source algal blooms.


Assuntos
Clorofila A , Qualidade da Água , Ecossistema , Eutrofização , Fitoplâncton
13.
Sci Total Environ ; 742: 140537, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32623173

RESUMO

For comprehensive insights into the change of sulfate reduction pathway responding to the toxic stress and the shift of microbial community and performance of sulfate reduction, we built a laboratory-scale expanded granular sludge bed reactor (EGSB) treating high-sulfate wastewater with elevated aniline concentrations from 0 to 480 mg/L. High-throughput sequencing and metagenomic approaches were applied to decipher the molecular mechanisms of sulfate reduction under aniline stress through taxonomic and functional profiles. The increasing aniline in the anaerobic system induced the accumulation of volatile fatty acids (VFA), further turned the bioreactor into acidification, which was the principal reason for the deterioration of system performance and finally resulted in the accumulation of toxic free sulfide. Moreover, aniline triggered the change of bacterial community and genes relating to sulfate reduction pathways. The increase of aniline from 0 to 320 mg/L enriched total sulfate-reducing bacteria (SRB), and the most abundant genus was Desulfomicrobium, accounting for 66.85-91.25% of total SRB. The assimilatory sulfate reduction pathway was obviously inhibited when aniline was over 160 mg/L, while genes associated with dissimilatory sulfate reduction pathways all exhibited an upward tendency with the increasing aniline content. The enrichment of aniline-resistant SRB (e.g. Desulfomicrobium) carrying genes associated with the dissimilatory sulfate reduction pathway also confirmed the underlying mechanism that sulfate reduction turned into dissimilation under high aniline condition. Taken together, these results comprehensively provided solid evidence for the effects of aniline on the biological sulfate reduction processes treating high-sulfate wastewater and the underlying molecular mechanisms which may highlight the important roles of SRB and related sulfate reduction genes during treatment.


Assuntos
Microbiota , Águas Residuárias , Anaerobiose , Compostos de Anilina , Reatores Biológicos , Esgotos , Sulfatos , Eliminação de Resíduos Líquidos
14.
Biomed Res Int ; 2020: 8163839, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32596377

RESUMO

Malignant melanoma (MM) is a highly metastatic and malignant cancer. Developing potential drugs with good efficacy and low toxicity for MM treatment is needed. Huaier, extracted from the mushroom Trametes robiniophila Murr, has been widely used in clinical anticancer treatments in China. A previous work done by our group confirmed that Huaier could inhibit cell proliferation and induce apoptosis in human melanoma cells. The current study is aimed at investigating the effects of Huaier on melanoma metastasis and angiogenesis in vitro and in vivo and to explore its possible mechanism of action. Our results showed that Huaier not only significantly inhibited the metastasis of A375 cells at the concentration ranging from 4 to 16 mg/ml (P < 0.05), which were determined by the wound healing assay and transwell assay in vitro, but also suppressed the MM tumor growth and metastatic cells to the liver in A375-bearing mice after oral administration at the dose of 5 mg/kg (P < 0.05). In addition, Huaier treatment downregulated the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), astrocyte-elevated gene-1 (AEG-1), and N-cadherin, while it upregulated E-cadherin expression in both the A375 cells and tumor tissues, which was detected using western blotting and RT-PCR (P < 0.05). Taken together, our data suggests that the antitumor and antimetastatic activities of Huaier are caused by the downregulation of the HIF-1α/VEGF and AEG-1 signaling pathways and by the inhibition of epithelial-mesenchymal transition (EMT). This study provides a new insight into the mechanism of Huaier on antimetastatic therapy and a new scientific basis for comprehensive treatment strategies for MM.

15.
Sci Total Environ ; 736: 139695, 2020 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-32497885

RESUMO

Nitrosamines, as a class of emerging frequently detected nitrogenous disinfection byproducts (N-DBPs) in drinking water, have gained increasing attention due to their potentially high health risk. Few studies focus on the occurrence variation and carcinogenic health risk of nitrosamines in drinking water systems. Our study aimed to investigate the spatial and temporal variability of nitrosamines in a drinking water system and to conduct a carcinogenic health risk assessment. Three types of water samples, including influent water, treated water and tap water, were collected monthly during an entire year in a drinking water system utilizing a combination of chlorine dioxide and chlorine in central China, and 9 nitrosamines were measured. The nitrosamine formation potentials (FPs) in influent water were also determined. N-nitrosodimethylamine (NDMA) was the most prevalent compound and was dominant in the water samples with average concentrations ranging from 2.5 to 67.4 ng/L, followed by N-nitrosodiethylamine (NDEA) and N-nitrosopiperidine (NPIP). Nitrosamine occurrence varied monthly, and significant seasonal differences were observed in tap water (p < .05). There were decreasing mean NDMA, NDEA and NPIP concentrations from influent water to treated water to tap water, but no significant spatial variability was observed within the water distribution system (p > .05). The average and 95th percentile total lifetime cancer risks for the three main nitrosamines were 4.83 × 10-5 and 4.48 × 10-4, respectively, exceeding the negligible risk level (10-6) proposed by the USEPA. Exposure to nitrosamines in drinking water posed a higher cancer risk for children than for adults, and children aged 0.75 to 1 years suffered the highest cancer risk. These results suggest that nitrosamine occurrence in tap water varied temporally but not spatially. Exposure to drinking water nitrosamines may pose a carcinogenic risk to human health, especially to children.


Assuntos
Água Potável/análise , Nitrosaminas/análise , Poluentes Químicos da Água/análise , Purificação da Água , Criança , China , Humanos , Lactente , Medição de Risco
16.
ACS Appl Mater Interfaces ; 12(26): 29110-29121, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32490661

RESUMO

Existing clinical cell therapies, which rely on the use of biological functionalities of living cells, can be further enhanced by conjugating functional particles to the cells to form cell-particle complexes. Disk-shaped microparticles produced by the top-down microfabrication approach possess unique advantages for this application. However, none of the current mechanisms for conjugating the microfabricated microparticles to the cells are principally applicable to all types of cells with therapeutic potentials. On the other hand, membrane intercalation is a well-established mechanism for attaching fluorescent molecules to living cells or for immobilizing cells on a solid surface. This paper reports a study on conjugating disk-shaped microparticles, referred to as micropatches, to living cells through membrane intercalation for the first time. The procedure for producing the cell-micropatch complexes features an unprecedented integration of microcontact printing of micropatches, end-grafting of linear molecules of octadecyl chain and poly(ethylene glycol) to the printed micropatches, and use of gelatin as a temperature-sensitive sacrificial layer to allow the formation and subsequent release of the cell-micropatch complexes. Complexes composed of mouse neuroblastoma cells were found to be stable in vitro, and the micropatch-bound cells were viable, proliferative, and differentiable. Moreover, complexes composed of four other types of cells were produced. The membrane-intercalation mechanism and the corresponding fabrication technique developed in this study are potentially applicable to a wide range of therapeutic cells and thus promise to be useful for developing new cell therapies enhanced by the disk-shaped microparticles.

17.
Food Funct ; 11(7): 6240-6250, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32596698

RESUMO

Nanosized iron is a promising candidate as an iron fortificant due to its good solubility and bioavailability. Here, ferric hydrolysis in the presence of salmon/herring sperm DNA yielded irregularly shaped, highly negatively charged DNA-stabilized ferric oxyhydroxide nanoparticles (DNA-FeONPs) aggregated from 2-4 nm primary spherical monomers, in which phosphodioxy groups of the DNA backbone served as the iron-nucleation sites with high molecular weight (>500 bp), double-stranded winding, and acidic environmental pH disfavoring DNA's iron-loading capacity. The calcein fluorescence-quenching kinetics of polarized Caco-2 cells revealed the involvement of divalent transporter 1, macropinocytosis and nucleolin-mediated endocytosis in intestinal iron absorption from DNA-FeONPs with low molecular weight (<500 bp) favoring the performance of DNA in aiding iron absorption. In anemic rats, dietary DNA-FeONPs showed >80% relative iron bioavailability compared to FeSO4 as per hemoglobin regeneration efficiencies and delivered intestinally available nanosized iron, as determined by luminal iron speciation analysis. Overall, fish sperm DNA is promising in stabilizing and delivering bioavailable nanosized iron.

18.
Ultrasonics ; 108: 106169, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32504983

RESUMO

The novelty of this paper is that a spiral-coil EMAT (electromagnetic acoustic transducer) is applied to rail subsurface inspection. To study the spiral-coil EMAT for rail subsurface inspection, the dominant mechanism is investigated emphatically. The interaction between the Lorentz-force mechanism and the magnetostriction mechanism is analyzed corresponding to the magnetic flux density and the frequency which has a significant effect on the magnetostriction mechanism. The effect of frequency on beam divergence is further discussed about the rail subsurface inspection using spiral-coil EMAT as well. A 2D FEM (finite element model) of spiral-coil EMAT is established and the simulation is carried out to analyze these issues. Besides, the experiments to inspect the subsurface crack of steel plate are carried out at various frequencies to verify the feasibility of the application. The experimental results demonstrate that the rail subsurface inspection by using the spiral-coil EMAT is feasible and the high frequency can contribute to distinguish the echo signal from the rail subsurface crack.

19.
Environ Sci Pollut Res Int ; 27(22): 27663-27673, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32394254

RESUMO

The Cu/TiO2 catalysts with the addition of Eu were developed by the sol-gel way for the selective catalytic reduction (SCR) of NOx by NH3. Activity tests revealed that CuEu/TiO2-0.15 catalyst showed the optimal de-NOx performance in a wide temperature range (150-300 °C), along with an admirable SO2 tolerance. According to characterization analysis, the relationship between the NH3-SCR performance and physicochemical characters of samples was explored. The adjunction of Eu on Cu/TiO2 catalyst can contribute to the formation of a large amount of Cu2+, adsorbed oxygen, and acid sites on the catalyst surface. Moreover, the Eu addition on Cu/TiO2 is favorable to the generation of activated NOx and NH3 substances adsorbed on the catalyst surface, which would conduce to the NH3-SCR process by Langmuir-Hinshelwood (L-H) mechanism effectively.


Assuntos
Amônia , Titânio , Catálise , Oxirredução
20.
Artigo em Inglês | MEDLINE | ID: mdl-32397945

RESUMO

Ascorbic acid is often used to enhance iron absorption in nutritional interventions, but it produces pro-oxidant effects in the presence of iron. This study aimed to evaluate ascorbate's role in iron toxicity on intestinal resistance against foodborne pathogens during iron supplementation/fortification. In polarized Caco-2 cell monolayers, compared to the iron-alone treatment, the iron-ascorbate co-treatment caused more than 2-fold increase in adhesion, invasion and translocation of Salmonella enterica serovar Typhimurium. According to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, lactate dehydrogenase release and transepithelial electrical resistance, the iron-ascorbate co-treatment resulted in reduced cell viability and increased impairment of cell membrane and paracellular permeability compared to the iron-alone treatment. Butylated hydroxytoluene protected cells against these prooxidant toxicities of ascorbate. Ascorbate completely restored iron-induced intracellular oxidant burst and depletion of cytosolic antioxidant reserve, according to dichlorodihydrofluorescein fluorescence and intracellular reduced glutathione levels. In Salmonella-infected C57BL/6 mice, iron-ascorbate co-supplementation resulted in greater loss of body weight and appetite, lower survival rate, shorter colon length, heavier intestinal microvilli damage, and more intestinal pathogen colonization and translocation than the iron-alone supplementation. Overall, ascorbate would exacerbate iron toxicity on intestinal resistance against Salmonella infection through pro-oxidant impairment of intestinal epithelial barrier from extracellular side and/or by facilitating intestinal pathogen colonization.

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