Gold nanomaterials obtained from black carrot extracts exhibit superior activity for crude glycerol electro-oxidation than gold nanoparticles obtained using the Turkevich method as reference ...material, and it was attributed to the abundance of {1 0 0} facets.
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•Gold nanomaterials obtained with black carrot extracts presented different shapes.•Au (1:5) displayed a 150 mV lower onset potential than Au Turkevich during GEOR.•Au (1:5) achieved 466.91 mA mg−1 during the crude glycerol electro-oxidation.•This current density was almost two times higher to that obtained with Au Turkevich.•The activity improvement was related to the abundance of {1 0 0} facets in Au (1:5).
In this work, gold nanomaterials were obtained using aqueous extracts of black carrots varying the molar ratio between the extract and the gold precursor salt (1:10, 1:5 and 2:5). Additionally, Au nanoparticles were obtained by the Turkevich method as reference material (Au Turkevich). Transmission electron micrographs indicated that a 1:5 ratio allowed to obtain a mixture of gold shapes like triangular, plate, rod, wire, and hemispherical shapes. The electrocatalytic evaluation for 0.5 M glycerol electro-oxidation indicated that Au (1:5) displayed higher current density (298.26 vs. 230.25 mA mg−1), and a more negative onset potential (ΔE = 150 mV) than Au Turkevich. In addition, Au (1:5) displayed higher current density during the electro-oxidation of 1 M crude glycerol (466.91 vs. 244.73 mA mg−1) with a similar potential difference. The improvement in activity and durability presented by Au (1:5) was attributed to the abundance of {1 0 0} facets as was determined by X-ray diffraction and HR-TEM.
Estimates of the brown carbon (BrC) absorption and their contribution to light absorption in ambient aerosols are poorly understood. The existing approaches to apportion light absorption into black ...carbon (BC) and BrC mainly use the assumption of fixed angstrom absorption exponent (AAE) for BC (1.0), which is not always true for ambient aerosols. Besides, these estimates are seldom validated, leaving significant uncertainty with derived values. Also, BrC absorption studies are largely focused on aqueous extracts, which truly do not represent the aerosolized form, hence the relationship between aqueous extracts and aerosolized form is a subject of research. With this in mind, we collected ambient PM2.5 filter samples at Lumbini, Nepal, at the northern edge of the Indo-Gangetic Plains (IGP) during winter 2017-18. These samples were analyzed for different compositions of carbonaceous aerosol and optical properties. BC and BrC absorptions were derived using a preexisting simplified two-component model but with “improved conditions”. Although BC dominated spectral absorption, BrC contribution for the carbonaceous aerosol absorption increased substantially at ultraviolet wavelengths (example 14.8–53.6% at 365 nm). Further water-soluble BrC absorption value in aerosol was found to be higher by 1.8 times to that obtained in aqueous extracts. Water-soluble OC contributed ∼65% to OC loading and 50% to BrC absorption at 365 nm, indicated the equally important role of water-insoluble organics. Mass absorption efficiency (MAE) of water-soluble BrC in aerosol was found to be 1.7 m2/g, lower to water-insoluble by 2.2 times. High BC MAE was observed which showed positive dependence on secondary coating. Sample collected during events with fog droplets showed a reduction in carbonaceous components loading and light absorption but enhancement in MAE for BrC and BC, signifying that aqueous processing can significantly modify the aerosol optical properties.
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•Aerosol optical absorption is apportioned to BC and BrC by using an improved optimization approach.•Water soluble BrC absorption in aerosol was higher by 1.8 times than in aqueous extract.•Water insoluble OC contributed ∼35% of the OC loading but 50% of the BrC absorption.•Elemental carbon constituted high proportion of char compared to soot.•Fog droplet events showed increase in MAE for BC and BrC.
An improved and validated approach developed to apportion light absorption by black and brown carbon.
•Field control and indoor experiments were both conducted.•Grazing intensity altered composition and concentration of aqueous extracts in A. frigida.•Allelopathy of A. frigida promoted plant growth ...of itself.•Allelopathy partly explain dominant status of A. frigida under heavy grazing.
Allelopathy is an important factor affecting plant community structure. However, few studies have focused on the mechanisms of allelopathy in the process of community succession driven by different grazing intensities. Therefore, field sampling, indoor experiments and field control experiments were conducted in a temperate grassland in northern China. We aimed to detect the impact of different grazing intensities on the chemical components and allelopathic effect of aqueous extracts of Artemisia frigida. The seed germination rate, radicle length, plant height and biomass of the four tested plant species were used to quantify the allelopathic effect of A. frigida. Grazing intensity altered the composition and concentration of chemical components contained in aqueous extracts of A. frigida. The maximum relative contents of 1,8-cineole and β-terpineol both occurred under heavy grazing. The allelopathic effect of A. frigida varied significantly among different grazing intensities and tested species, and the interaction effects between grazing intensity and tested species were also significant. The allelopathic effects of A. frigida significantly influenced the seed germination rate and radicle length of all the test species except Medicago sativa. The aqueous extracts of A. frigida also significantly affected the aboveground, belowground and total biomass of M. sativa and Melilotus officinalis. The allelopathic effect of A. frigida significantly promoted its own plant biomass and inhibited the plant biomass of Stipa krylovii. Our results confirmed that the allelopathic effects of A. frigida partly regulated the process of species composition in degraded rangelands.
This study describes a new bioaugmentation alternative based on the application of aqueous aerated extracts from a biomixture acclimated with ibuprofen, diclofenac and triclosan. This bioaugmentation ...strategy was assayed in biopurification systems (BPS) and in contaminated aqueous solutions to accelerate the removal of these emerging contaminants. Sterilized extracts or extracts from the initial uncontaminated biomixture were used as controls. In BPS, the dissipation of 90% of diclofenac and triclosan required, respectively, 60 and 108 days less than in the controls. The metabolite methyl-triclosan was determined at levels 12 times lower than in controls. In the bioaugmented solutions, ibuprofen was almost completely eliminated (99%) in 21 days and its hydroxylated metabolites were also determined to be at lower levels than in the controls. The plasmidome of acclimated biomixtures and its extract appeared to maintain certain types of plasmids but degradation related genes became less evident. Several dominant OTUs found in the extract identified as Flavobacterium and Fluviicola of the phylum Bacteroidetes, Thermomicrobia (phylum Chloroflexi) and Nonomuraea (phylum Actinobacteria), may be responsible for the enhanced dissipation of these contaminants. This bioaugmentation strategy represents an advantageous tool to facilitate in situ bioaugmentation.
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•Simple and fast isolation of microbial consortia by aerated aqueous extraction.•Extracts enhanced removal of ibuprofen and their metabolites in aqueous media•Enhanced triclosan and methyl-TCS removal in bioaugmented bioremediation system.•The contaminated systems were enriched in some bacterial taxa and plasmid types.•The extract showed dominant OTUs that likely participate in PPCP dissipation
Alginate/gelatin hydrogel (Alg-Gel) scaffold has been applied in tissue engineering, but the research on its application in dental tissues regeneration is still lacking. We investigated the effect of ...this scaffold on human dental pulp stem cells (hDPSCs).
hDPSCs were cultured in both Alg-Gel and 3D-printed Alg-Gel scaffolds. Cell growth and adhesion were compared using fluorescein isothiocyanate–phalloidin staining and scanning electron microscopic micrographs. Changes in the proliferation in hDPSCs cultured in the complete culture medium containing aqueous extracts of the Alg-Gel or 3D-printed Alg-Gel scaffolds were examined using Cell Counting Kit-8 assay and flow cytometry analysis. Cells were cultured in the mineralization medium containing aqueous extracts of the Alg-Gel or 3D-printed Alg-Gel scaffolds for 7 or 14 days, and the differentiation of cells was shown by alizarin red S staining and alkaline phosphatase staining. The messenger RNA and protein expression of mineralization-related genes were detected with real-time polymerase chain reaction and Western blotting. Elemental analysis was used to test the material extract composition.
More cells were grown and adhered to the 3D-printed Alg-Gel scaffolds than the Alg-Gel scaffolds. The aqueous extracts of 3D-printed scaffolds can promote cell proliferation, and compared with Alg-Gel scaffolds, the extracts of 3D-printed scaffolds were more effective. Compared with the negative control group, 3D-printed Alg-Gel scaffold and Alg-Gel scaffold aqueous extracts promoted osteogenic/odontoblastic differentiation of hDPSCs with the enhanced formation of bone-like nodules and the alkaline phosphatase staining. The expression of mineralization-related genes was also up-regulated. 3D-printed scaffold aqueous extract contained more calcium and phosphorus ions than the Alg-Gel scaffold.
These findings suggest that compared with the Alg-Gel scaffold, 3D-printed Alg-Gel is more suitable for the growth of hDPSCs, and the scaffold extracts can better promote cell proliferation and differentiation.
•A 3-dimensional (3D) scaffold is more suitable for cell growth and adhesion.•3D-printed scaffold extract boosts human dental pulp stem cells (hDPSCs) growth.•3D-printed scaffold extract promotes osteogenic differentiation of hDPSCs.•3D-printed scaffold extract promotes odontogenic differentiation of hDPSCs.
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