•The SWR was much quicker than the SWI under a small horizontal hydraulic gradient.•Hysteresis was found in the relationship between the saltwater wedge toe location and salt mass.•The response of ...SWI and SWR to the inland watertable variations was affected by tidal conditions.
Based on combined laboratory experiments and numerical simulations, this paper examined seawater intrusion (SWI) and seawater retreat (SWR) processes caused by abrupt inland watertable changes in a laboratory-scale unconfined aquifer (length of 7.7 m and thickness of 1.0 m) subjected to a synthetic sinusoidal tide. The results showed that the salinity distribution was relatively stable and that SWI and SWR processes were almost temporally symmetrical given relatively large horizontal hydraulic gradients (0.0269, 0.0209 and 0.0149) between the inland watertable and the mean sea level. However, the salt distribution changed significantly in response to the inland watertable variations when the horizontal hydraulic gradient was relatively small (0.0030). The speed of the SWI and SWR response to the inland watertable variations was temporally asymmetric, e.g., SWR was quicker than SWI by a factor of 9 with respect to the observed saltwater wedge toe locations. As a relatively thick mixing zone (transition between freshwater and saltwater zones) was induced by the tide, simulated saltwater wedge toe locations, as indicated by the 5%, 50% and 95% isohalines, changed inconsistently. Different hysteresis behaviors were found in the relationship between the SW toe locations and total salt mass stored in the aquifer. Sensitivity analyses demonstrated that the response of both SWI and SWR to the inland watertable variations could be prolonged by a decreased tidal amplitude or decreased tidal period.
Cutaneous wound healing and regeneration have become a recognized health challenge in the world, which causes severe damage to the mental and physical health of patients. Human adipose-derived ...mesenchymal stem cells (hADSC) play an essential role in wound healing via their paracrine function. Exosomes secreted by hADSC may contribute to this progress. In this study, we investigated the potential clinical application roles of hADSC and hADSC-derived exosomes (hADSC-Exo) in cutaneous wound healing.
hADSC-Exo was isolated from human hADSC by ultracentrifugation. Mice were subjected to a full-thickness skin biopsy experiment and treated with either control vehicle or hADSC or hADSC-Exo by smearing administration (sm) or subcutaneous administration (sc) or intravenous administration (iv). The efficacy of hADSC and hADSC-Exo on wound healing was evaluated by measuring wound closure rates, histological analysis.
Combined application of local hADSC-Exo smearing and hADSC/hADSC-Exo intravenous administration offered the additional benefit of promoting wound healing, accelerating re-epithelialization, reducing scar widths, and enhancing angiogenesis and collagen synthesis. Either topical application of hADSC-Exo or systemic administration with hADSC/hADSC-Exo appeared more effective in stimulating cell proliferation, inhibiting cell apoptosis and inflammation, and promoting skin elasticity and barrier integrity, with increased genes expression of PCNA, VEGF, collagen III, Filaggrin, Loricrin, and AQP3, with decreased genes expression of TNF-alpha.
Our findings suggest that the combined administration of hADSC/hADSC-Exo can facilitate cutaneous wound healing and reduce scar formation. These data provide the first evidence for the feasibility of smearing of hADSC-Exo as a cell-free therapy in treating cutaneous wounds, and the potential clinical value of combined administration of hADSC/hADSC-Exo.
•Evaporation increases pore-water salinity in the shallow soil layer.•Salt is trapped in the shallow soil layer by evaporation.•A higher mean sea level enhances the evaporation-induced salt trapping.
...Ocean surge inundation occurs frequently in low-lying coastal areas worldwide. While studies have been conducted to examine aquifer salinization and recovery caused by ocean surge inundation, evaporation is predominantly overlooked. Based on numerical simulations considering variably saturated, density-dependent pore-water flow and salt transport, this study examines the combined effects of evaporation and ocean surge inundation on soil salinization in coastal unconfined aquifers. The results show that evaporation enhances soil salinization caused by ocean surge inundation. Due to evaporation-induced water uptake, the downward movement of salt is weakened and the salt from the ocean surge inundation is significantly trapped in the unsaturated zone. The pore-water salinity in the shallow soil layer is increased by soil evaporation, particularly in the low-elevation area with longer seawater inundation. The sensitive analysis shows that the evaporation-enhanced soil salinization is more remarkable for silt-loam and clay-loam aquifers rather than sandy-loam aquifers. A higher mean sea level favors salt trapping in the shallow soil layer of aquifers. These results demonstrate the importance of evaporation on soil salinization caused by ocean surge inundation, and that could be considered in future studies.
Soil salinity is an increasingly serious problem worldwide that reduces agricultural output potential. Selected beneficial soil bacteria can promote plant growth and augment tolerance to biotic and ...abiotic stresses. Bacillus subtilis strain GB03 has been shown to confer growth promotion and abiotic stress tolerance in the model plant Arabidopsis thaliana. Here we examined the effect of this beneficial soil bacterium on salt tolerance in the legume forage crop, white clover. Plants of white clover (Trifolium repens L. cultivar Huia) were grown from seeds with or without soil inoculation of the beneficial soil bacterium Bacillus subtilis GB03 supplemented with 0, 50, 100, or 150 mM NaCl water into soil. Growth parameters, chlorophyll content, malondialdehyde (MDA) content and osmotic potential were monitored during the growth cycle. Endogenous Na(+) and K(+) contents were determined at the time of harvest. White clover plants grown in GB03-inoculated soil were significantly larger than non-inoculated controls with respect to shoot height, root length, plant biomass, leaf area and chlorophyll content; leaf MDA content under saline condition and leaf osmotic potential under severe salinity condition (150 mM NaCl) were significantly decreased. Furthermore, GB03 significantly decreased shoot and root Na(+) accumulation and thereby improved K(+)/Na(+) ratio when GB03-inoculated plants were grown under elevated salt conditions. The results indicate that soil inoculation with GB03 promotes white clover growth under both non-saline and saline conditions by directly or indirectly regulating plant chlorophyll content, leaf osmotic potential, cell membrane integrity and ion accumulation.
Herein, a novel electrochemical ultrasensitive immunosensor was designed for detecting prostate-specific antigen (PSA) with three-dimensional (3D) PtCu hollow nanoframes (PtCu HNFs) as signal ...amplification. The highly opened PtCu HNFs were synthesized by a one-pot solvothermal method with cetyltrimethylammonium chloride (CTAC) and trishydroxymethyl aminomethane (Tris) as co-structuring directors. The architectures enlarged the loading of prostate specific antibodies (Ab) and efficiently catalyzed hydrogen peroxide (H2O2) reaction, ultimately amplifying the signals. And polylysine was used to disperse PtCu HNFs, improve the biocompatibility and bind the Ab on the electrode surface. The fabricated immunosensor exhibited lower detection limit (0.003 ng mL–1, S/N = 3), and wider linear range (0.01–100.0 ng mL–1), along with the improved reproducibility, selectivity and stability for the assay of PSA. Thus, it is a desirable platform for PSA detection in clinical diagnosis and practical applications.
•Uniform PtCu HNFs were synthesized by a simple solvothermal method.•Tris and CTAC acted as the co-structure-directing agents.•Polylysine can well disperse PtCu HNFs with increased biocompatibility.•PtCu HNFs was constructed for PSA immunosensor with excellent analytic performance.
Haloxylon ammodendron, a C4 perennial, succulent and xero-halophytic shrub, is highly resistant to harsh environments, therefore, exploring the stress resistance mechanism will be beneficial for the ...use of xerophytes to prevent desertification. To determine osmotic adjustment (OA) and antioxidase functions under simulated drought stress, 8-week-old seedlings were treated with sorbitol solutions to maintain osmotic potentials (Ψs) at a control and −0.5 and −1.0 MPa. Under −0.5 MPa osmotic stress, H. ammodendron stably maintained the water content of assimilating branches, a result that was not significantly different from the result of the control group. Moreover, the Ψs decreased significantly, which helped plants absorb water efficiently from the environment, as H. ammodendron accumulated massive osmotic regulators in its assimilating branches to adjust shoot Ψs. Specifically, the contribution of Na+ to shoot Ψs was up to 45%, and Na+ became the main osmotic regulator of OA. During the treatments, the content and contribution of K+ remained stable. However, the total contribution of three organic osmotic regulators (free proline, betaine and soluble sugar) was only 20%, and betaine was the main organic osmotic regulator, accounting for approximately 15% of the 20% contribution. Moreover, H. ammodendron seedlings presented strong antioxidases, especially when there was a high activity level of superoxide dismutase, and with an increase in treatment time and degree of osmotic stress, the activity of peroxidase and catalase increased significantly. Substantial accumulation of osmotic adjustment substances was an important strategy for H. ammodendron to cope with simulated drought stress, in particular, H. ammodendron absorbed much Na+ and transported Na+ into the assimilating branch for OA. The scavenging of reactive oxygen species by antioxidases was another adaptation strategy for H. ammodendron to adapt to simulated drought stress.
•Osmotic adjustment played important role in Haloxylon ammodendron under drought stress.•Na+ was accumulated largely in assimilating branch for osmotic adjustment.•Removing ROS through antioxidases was another important strategy.
Abscisic acid (ABA), stress, and ripening-induced proteins (ASR), which belong to the ABA/WDS domain superfamily, are involved in the plant response to abiotic stresses. Haloxylon ammodendron is a ...succulent xerohalophyte species that exhibits strong resistance to abiotic stress. In this study, we isolated HaASR2 from H. ammodendron and demonstrated its detailed molecular function for drought and salt stress tolerance. HaASR2 interacted with the HaNHX1 protein, and its expression was significantly up-regulated under osmotic stress. Overexpression of HaASR2 improved drought and salt tolerance by enhancing water use efficiency and photosynthetic capacity in Arabidopsis thaliana. Overexpression of HaASR2 maintained the homeostasis of reactive oxygen species (ROS) and decreased sensitivity to exogenous ABA and endogenous ABA levels by down-regulating ABA biosynthesis genes under drought stress. Furthermore, a transcriptomic comparison between wild-type and HaASR2 transgenic Arabidopsis plants indicated that HaASR2 significantly induced the expression of 896 genes in roots and 406 genes in shoots under osmotic stress. Gene ontology (GO) enrichment analysis showed that those DEGs were mainly involved in ROS scavenging, metal ion homeostasis, response to hormone stimulus, etc. The results demonstrated that HaASR2 from the desert shrub, H. ammodendron, plays a critical role in plant adaptation to drought and salt stress and could be a promising gene for the genetic improvement of crop abiotic stress tolerance.
•HaASR2 was isolated from a desert shrub, Haloxylon ammodendron, and its molecular function was analyzed in Arabidopsis.•Overexpression of HaASR2 enhanced drought and salt tolerance through improving water use efficiency and photosynthetic capacity in Arabidopsis.•Overexpression of HaASR2 maintained ROS homeostasis and decreased the sensitivity of plants to exogenous and endogenous ABA.
Arsenic, a toxic component in coal-fired flue gas, is poisonous to the commercial selective catalytic reduction (SCR) denitrification catalysts. To unveil the arsenic poisoning mechanism on ...commercial SCR catalysts, fresh and 1 year used arsenic-poisoned plate-type V2O5–MoO3/TiO2 catalysts from a coal-fired power plant in the Inner Mongolia Province of China were systematically analyzed with SCR activity and characterization experiments. The results indicated that the plate-type V2O5–MoO3/TiO2 catalysts possessed a certain ability to resist arsenic poisoning. The average denitrification efficiency of the poisoned catalysts was maintained over 70% at 350 °C, even though the arsenic content was as high as 7 wt %, compared to the denitrification efficiency of 87.35% for the fresh catalyst. Characterization results indicated that both physical and chemical factors resulted in the deactivation of catalysts by arsenic. The surface area and amount of surface acid sites of the used catalysts decreased, which inhibited the adsorption of ammonia. The redox capacity of the used catalysts also decreased as a result of the increase of tetravalent vanadium (V4+) and the decrease of surface chemisorbed oxygen. Furthermore, catalysts at different installation positions in the SCR system had different denitrification activities and deactivation mechanisms. The major deactivation factor for the catalysts in the top layer was physical blockage, while the chemical deactivation was dominant for the catalysts in the middle layer.
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To realize the efficient and complete removal of organic pollutants in waste water, it is highly urgent for scalable synthesis of either self-supported bimetallic nanocatalysts or ...anchored on carbon-based materials. In this study, a simple one-pot coreduction method was developed for preparing well-dispersed AgPd alloyed nanoclusters uniformly dispersed on reduced graphene oxide (AgPd NCs/rGO) at room temperature by utilizing 5-azacytosine as the capping agent. The nanocomposites were characterized by a set of physical characterizations. The formation mechanism and catalytic mechanism were discussed in some details. Moreover, the prepared AgPd NCs/rGO exhibited dramatically increased catalytic properties towards the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4 when compared to commercial Pd/C (20 wt.%).
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