We numerically investigate the behaviors of a hydrodynamic squirmer interacting with a circular obstacle using the lattice Boltzmann method. It is interesting to find that in most cases, pullers ...(gaining thrust from the front) move forward while pushers (gaining thrust from the rear) move backward. We describe six swimming patterns of the squirmer: orbiting forward, ∞-loop, dancing forward, C-loop, orbiting backward, and scattering; notably, three of these have not been previously reported. The association between pressure and viscous stress can reasonably explain the movement of the squirmer near the obstacle. In certain modes, squirmers can swim faster near obstacles. The swimming Reynolds number Res and dipolarity β have significant effects on the averaged velocity and Strouhal number of the swimming patterns. A stronger polarity encourages the squirmers to swim faster and “bounce” more often.
Heavy metal contamination in soil has attracted great attention worldwide. In situ stabilization has been considered an effective way to remediate soils contaminated by heavy metals. In the present ...research, a multiple-modified biochar (BCM) was prepared to stabilize Cd and Cu contamination in two different soils: a farmland soil (JYS) and a vegetable soil (ZZS). The results showed that BCM was a porous-like flake material and that modification increased its specific surface area and surface functional groups. The incubation experiment indicated that BCM decreased diethylenetriaminepentaacetic (DTPA)-extractable Cd and Cu by 92.02% and 100.00% for JYS and 90.27% and 100.00% for ZZS, respectively. The toxicity characteristic leaching procedure (TCLP)-extractable Cd and Cu decreased 66.46% and 100.00% for JYS and 46.33% and 100.00% for ZZS, respectively. BCM also reduced the mobility of Cd and Cu in soil and transformed them to more stable fractions. In addition, the application of BCM significantly increased the soil dehydrogenase, organic matter content and available K (p < 0.05). These results indicate that BCM has great potential in the remediation of Cd- and Cu-contaminated soil.
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•Multiple modifications improved the specific surface area and surface active groups of biochar.•BCM efficiently reduced the bioavailability Cd and Cu.•BCM reduced the leachability of Cd and Cu.•BCM transformed Cd and Cu to a more stable fraction.•BCM improved the properties of Cd- and Cu-contaminated soils.
A 6 weeks pot culture experiment was carried out to investigate the stabilization effects of a modified biochar (BCM) on metals in contaminated soil and the uptake of these metals by wheat seedlings. ...The results showed that the application of BCM significantly increased the soil fertility, the biomass of wheat seedling roots increased by more than 50%, and soil dehydrogenase (DHA) and catalase (CAT) activities increased by 369.23% and 12.61%, respectively. In addition, with the application of BCM, the diethylenetriaminepentaacetic acid extractable (DTPA-extractable) Cd, Pb, Cu and Zn in soil were reduced from 2.34 to 0.38 mg/kg, from 49.27 to 25.65 mg/kg, from 3.55 mg/kg to below the detection limit and from 4.05 to 3.55 mg/kg, respectively. Correspondingly, the uptake of these metals in wheat roots and shoots decreased by 62.43% and 79.83% for Cd, 73.21% and 66.32% for Pb, 57.98% and 68.92% for Cu, and 40.42% and 43.66% for Zn. Furthermore, BCM application decreased the abundance and alpha diversity of soil bacteria and changed the soil bacterial community structure dramatically. Overall, BCM has great potential for the remediation of metal-contaminated soils, but its long-term impact on soil metals and biota need further research.
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•Modified biochar (BCM) significantly reduced activity of metals in the soil.•BCM inhibited the uptake of metals by wheat seedlings.•BCM improved soil properties and increased soil enzyme activity.•BCM decreased soil bacterial diversity and changed the soil bacterial community.
Purpose
Sediment contaminated with metals constitutes a worldwide environmental problem. Biochar-based materials are widely applied in soil/sediment remediation due to their high adsorption capacity ...and cost-effectiveness. In this study, multiple modified biochar (BCM) were used to stabilize metals in contaminated river sediment.
Materials and methods
BCM was mixed with metal-contaminated river sediment at doses of 0%, 1%, 2% and 3% (w/w, represented as CK, BCM1, BCM2 and BCM3, respectively). Changes in the availability, leachability and fractions of metals and in sediment chemical properties and enzyme activities (catalase, dehydrogenase) were analysed.
Results and discussion
Results showed that the application of BCM effectively reduced the levels of diethylenetriaminepentaacetic (DTPA)-extractable, CaCl
2
-extractable and toxicity characteristic leaching procedure (TCLP)-extractable metals in the sediment. In the BCM3 treatment, DTPA-extractable, levels of CaCl
2
-extractable and TCLP-extractable metals decreased by 56.61%, 98.20% and 23.57% for Cd, 99.99%, 97.04% and 71.15% for Cu and 82.21%, 97.77% and 55.27% for Ni, respectively. The levels of DTPA-extractable and TCLP-extractable Pb decreased 69.60% and 69.24%, respectively, and the levels of CaCl
2
-extractable and TCLP-extractable Zn decreased 49.81% and 55.27%, respectively. In addition, BCM application (BCM3) transformed the acid-soluble Cu, Cd and Ni to a more stable fraction, and the levels of acid-soluble Cd and Ni decreased by 28.23% and 5.81%, respectively. The level of acid-soluble Cu was below the detection limit, and reducible Cu was decreased 0.60% in the BCM3 treatment. However, the influence of BCM on the fractions of Pb and Zn was not significant (
p
< 0.05). In addition, the levels of organic matter, available P and NH
4
+
-N in the treated sediment were significantly increased compared with those undergoing CK treatment. BCM has insignificant influence on sediment pH, available K and NO
3
-N levels and sediment enzyme activity.
Conclusions
BCM simultaneously reduced the bioavailability and leachability of multiple metals in contaminated sediment. These results suggest that BCM has great potential for the remediation of sediments contaminated with metals.
exhibits high edible and medicinal value; however, there have been no reports on the exploration of its endophyte resources. Here, we conducted analyses encompassing plant metabolomics, microbial ...diversity, and the biological activities of endophytic metabolites in
.
. High-throughput sequencing identified 4,913 endophytic fungal amplicon sequence variants (ASVs) and 1,703 endophytic bacterial ASVs from the roots, stems, leaves, flowers, and fruits of
. Fungi were classified into 5 phyla, 24 classes, 75 orders, 170 families, and 313 genera, while bacteria belonged to 21 phyla, 47 classes, 93 orders, 145 families, and 232 genera. Furthermore, there were significant differences in the composition and content of metabolites in different tissues of
.
. Spearman's correlation analysis of the differential metabolites and endophytes revealed that the community composition of the endophytes correlated with plant-rich metabolites. The internal transcribed spacer sequences of 105 isolates were determined, and phylogenetic analyses revealed that these fungi were distributed into three phyla (Ascomycota, Basidiomycota, and Mucoromycota) and 20 genera. Moreover, 16S rDNA sequencing of 46 bacteria revealed they were distributed in 16 genera in three phyla:
. The antimicrobial activities (filter paper method) and antioxidant activity (DPPH and ABTS assays) of crude extracts obtained from 68 fungal and 20 bacterial strains cultured in different media were evaluated. Additionally, the α-glucosidase inhibitory activity of the fungal extracts was examined. The results showed that 88.6% of the strains exhibited antimicrobial activity, 55.7% exhibited antioxidant activity, and 85% of the fungi exhibited α-glucosidase inhibitory activity. The research suggested that the endophytes of
.
are highly diverse and have the potential to produce bioactive metabolites, providing abundant species resources for developing antibiotics, antioxidants and hypoglycemic drugs.
Abstract Cavitation is an important factor causing vibration and noise of water-jet pump. High-performance ships require water-jet pumps with high efficiency and low noise at high speeds. At present, ...the cavitation flow phenomenon and interference mechanism of the water-jet pump under different flow rates are not clear enough. This paper takes the mixed-flow water jet propulsion pump as the research object. The flow structure of the cavitation vortex of the water-jet pump under different flow rates was obtained by high-speed photography (HSP). Through comparison of numerical simulation and test results, the cavitation performance curves and cavitation flow structures of the water jet pump under five different flow rates were obtained. The influence of cavitation vortex structure on the performance of water-jet pump under different flow rates was obtained. The correlation between cavitation performance and cavitation vortex structure under different flow rates was established. This research work will help to understand the impact of the cavitation vortex structure of the water-jet pump under different flow rates and capture the evolution law of the cavitation vortex structure of the water-jet pump under different flow rates. And provide reference for improving the cavitation performance of water-jet pumps.
In this study, the secondary metabolites of a lichen-derived actinomycete strain
Amycolatopsis
sp. YIM 130687 were investigated intensively by using three different media (4
#
, 302
#
, and 312
#
) ...for fermentation. A total of 21 compounds were isolated from the fermented extraction of the strain. The structures of all compounds were identified by the examination of HRESIMS and NMR spectra. Compounds
1–3
,
5
,
6
,
21
were only found in the cultivation on 302
#
medium, while compounds
4
,
9–11
were only obtained when the strain was cultured on 312
#
medium. On the other hand, compounds
7
,
8
, and
20
were only isolated from the fermentation product on 4
#
medium. The antimicrobial activity test showed that compound
9
had significant inhibitory effects on bacterial pathogens of
Staphylococcus aureus
and MRSA with the MICs of 2 μg/ml and fungal pathogens of
Botrytis cinerea
and
Fusarium graminearum
with the MICs of 1 μg/ml.
Artemia is a genus of halophilic zooplanktons comprising bisexual and parthenogenetic forms, which is an important model for investigating adaption to hypersaline ecosystems. The genus Artemia in ...China comprises four species: A. sinica, A. tibetiana, A. franciscana and A. parthenogenetica. To investigate the evolutionary relationship of bisexual and parthenogenetic Artemia in China, we analyzed the morphometrics and phylogenetics among twenty-two geographical populations in China. We found significant morphological differentiation across different species and strains of Artemia in China, which exhibited a high level of intra-population variation. We also found overlaps in morphological characteristics between populations, which may raise challenges for the classification of Artemia species using traditional morphological methods. A. franciscana, which originated from various regions in America, was generally distributed along the Chinese coastlines through multiple human introductions. Additionally, native Asian clades split into Western and Eastern Lineages during the late Miocene due to the Himalayan orogeny. Within the Western Lineage, A. tibetiana can be grouped into three taxon units: A. tibeitiana, A. sorgeloosi and A. urmiana. We also found that the distribution and genetic structure of A. sinica were influenced by climate oscillations during the Pleistocene, which might play a pivotal role in driving the formation of parthenogenetic strains in the Eastern Lineage. Overall, our study provides new insight into invertebrate evolution under geographical and climatic impacts in hypersaline environments.
Cefotaxime (CTX) is an easily detectable antibiotic pollutant in the water environment, but little is known about its toxic effects on aquatic invertebrates, especially on the intestine. Here, we ...determined the oxidative stress conditions of
under CTX exposure with five concentrations (0, 0.001, 0.01, 0.1 and 1 mg/L) for 14 days. After that, we focused on changes in intestinal tissue morphology and gut microbiota in
caused by CTX exposure at 0.01 mg/L. We found malondialdehyde (MDA) was elevated in CTX treatment groups, suggesting the obvious antibiotic-induced oxidative stress. We also found CTX exposure at 0.01 mg/L decreased the villus height and muscularis thickness in gut tissue. The 16S rRNA gene analysis indicated that CTX exposure reshaped the gut microbiota diversity and community composition. Proteobacteria, Actinobacteriota and Bacteroidota were the most widely represented phyla in
gut. The exposure to CTX led to the absence of Verrucomicrobia in dominant phyla and an increase in Bacteroidota abundance. At the genus level, eleven genera with an abundance greater than 0.1% exhibited statistically significant differences among groups. Furthermore, changes in gut microbiota composition were accompanied by modifications in gut microbiota functions, with an up-regulation in amino acid and drug metabolism functions and a down-regulation in xenobiotic biodegradation and lipid metabolism-related functions under CTX exposure. Overall, our study enhances our understanding of the intestinal damage and microbiota disorder caused by the cefotaxime pollutant in aquatic invertebrates, which would provide guidance for healthy aquaculture.
Abstract
Xiaoxuming decoction is a traditional Chinese medicine that has been widely used in the clinical treatment of ischemic stroke (IS). This study employed network pharmacology to identify the ...bioactive molecules and therapeutic mechanism of Xiaoxuming decoction against IS. First, the traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP) was utilized to obtain the ingredients and potential target proteins related to IS in the Xiaoxuming decoction. Subsequently, known target proteins related to IS were collected from online Mendelian inheritance in man (OMIM), Disgenet, and Gencards databases. The mechanism of Xiaoxuming decoction against IS was identified by enrichment analysis of gene ontology (GO) and Kyoto Encyclopedia of genes and genomes (KEGG). Additionally, protein–protein interaction data were obtained from the search tool for the retrieval of interacting genes/proteins (STRING). The hub gene was further screened out from the gene expression omnibus (GEO) and verified by molecular docking. The study identified a total of 183 candidate molecules and 140 targets related to IS. These candidate targets regulate biological processes including inflammation, autophagy, oxidative stress, and vascular reaction. Our findings provide a comprehensive demonstration of the active compounds, key targets, main signaling pathways, and underlying molecular mechanisms of Xiaoxuming decoction in treating IS.
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