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This study was implemented in order to explore the effect of ultrasound-assisted H2O2-Vitamin C (VC) degradation on ginseng polysaccharides (GPS). GPS were extracted from ginseng by water extraction followed by alcohol precipitation and separated and purified by DEAE-52 cellulose and Sephadex G-100 column chromatography. Fraction GPS-1A was degraded into a low-molecular-mass polysaccharide DGPS-1A under the following conditions: sample concentration 4.2 mg/mL, H2O2-VC concentration 10.3 mmol/L and ultrasound power 1 006 W. Meanwhile, the structural characteristics of GPS-1A and DGPS-1A, their inhibitory effects on major starch digestive enzymes and their antioxidant activities were studied. The results showed that the relative molecular masses of GPS-1A and DGPS-1A were 135 and 77.8, respectively, but the composition of monosaccharides did not change after ultrasound-assisted H2O2-VC degradation. The Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectra also showed that the major functional groups of the polysaccharide were not damaged after degradation. In addition, DGPS-1A showed stronger in vitro antioxidant and hypoglycemic activities than did GPS-1A. At the maximum concentration (6 mg/mL), the inhibition rates of α-glucosidase and α-amylase and the scavenging rates of 1,1-diphenyl-2-trichrophenylhydrazine radical (DPPH) and hydroxyl radical by DGPS-1A were (90.83 ± 3.04)%, (78.03 ± 2.29)%, (89.56 ± 1.17)% and (76.85 ± 1.63)%, compared to only (65.16 ± 2.53)%, (54.04 ± 1.97)%, (31.77 ± 2.42)% and (30.85 ± 2.29)% with GPS-1A, respectively. Moreover, the reducing power of DGPS-1A was 2.03 times higher than that of GPS-1A. These results indicate that ultrasound-assisted H2O2-VC degradation of ginseng polysaccharides has potential application in the development of functional foods with antioxidant and hypoglycemic activities.

In this study, the fermentation supernatant, cells and disrupted cell supernatant of five strains of lactic acid bacteria (LAB) were screened for tyrosinase inhibitory activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The results showed that the tyrosinase inhibitory activity of the fermentation supernatant was much higher than that of the cells and the disrupted cell supernatant. The percentage inhibition of tyrosinase activity by the fermentation supernatant of strain MNJ-9 was 68.9% compared to only 50.9% with the cells and 34.8% with the disrupted cell supernatant. The fermentation supernatant of strain MNJ-9 scavenged 93.1% of DPPH radical. Meanwhile, MNJ-9 was identified by 16S rDNA gene sequencing. The major components of the fermentation supernatant of MNJ-9 were investigated using untargeted metabolomics based on liquid chromatography-mass spectrometry (LC-MS). The tyrosinase inhibitory activity and DPPH radical scavenging capacity of 10 of the major components were measured. The results showed that 5-aminovaleric acid had the highest tyrosinase inhibitory activity and DPPH radical scavenging capacity. The cytotoxicity of 5-aminovaleric acid on mouse melanoma cells (B16F10), and its impact on the melanin content and tyrosinase activity of B16F10 cells were determined to evaluate its whitening ability. The results showed that the cell survival rate was equal to or over 80% after culture for 72 h with 70 μg/mL of 5-aminovaleric acid, indicating no apparent cytotoxicity. At 5-aminovaleric acid concentrations of 10–70 μg/mL, the intracellular melanin content and tyrosinase activity were 85.4%–45.2% and 76.53%–40.5%, respectively. This indicates that 5-aminovaleric acid has some whitening ability.

Freeze–thaw cycles are frequently overlooked as a pivotal factor contributing to leakage and structural failures in clayey soil-impermeable barriers used in landfills or tailings repositories in regions subject to seasonal freezing. This investigation explores the recovery and residual strength properties of Jilin ball clay undergoing six freeze–thaw cycles, and assesses the pore structure characteristics through a series of nuclear magnetic resonance (NMR) tests. The results indicate that normal stress has a greater impact on peak recovery strength than dry density and rest periods. Cohesion increases earlier and more significantly during rest periods compared to internal friction angle. Although the pore diameter remains consistent within the micropores during the freeze–thaw cycles, the soil's structural integrity undergoes notable changes. The concluding analysis provides valuable insights for the construction and management of impermeable barriers in landfills or tailings repositories within seasonally frozen areas. [ABSTRACT FROM AUTHOR]

Currently, the treatment of miscellaneous fill foundations, composed of a mixture of domestic garbage, construction solid waste, and natural soil, presents a significant challenge in urban peripheral engineering construction. This paper discusses the application of vibrating rod compaction technology for foundation treatment in Xinjiang. It evaluates the effectiveness of cross-section vibrating rod compaction equipment in reinforcing fine-grained miscellaneous fill foundations. The study analyzes the impact of construction disturbances caused by the insertion of the vibrating rod, monitoring horizontal stresses at various depths. Both laboratory and field tests show significant improvements: soil dry density increased by 8% to 18%, porosity decreased by 10% to 23%, compression modulus increased by 22% to 246%, and compression coefficient decreased by 8% to 70%. Additionally, cohesion (C) and angle of friction (ɸ) saw increases ranging from 7 to 38% and 3% to 25%, respectively. Below a depth of 3 m, cone tip resistance exceeded 10 MPa, and sidewall friction resistance increased to over 100 kPa, surpassing pre-treatment values. The standard penetration test results doubled stroke length compared to pre-treatment, indicating a substantial improvement in foundation bearing capacity. Surface wave tests before and after treatment showed a 15% increase in wave velocity, reflecting a more compact soil structure. The vibrating rod compaction method is innovative, energy-efficient, environmentally friendly, and economically beneficial, holding great potential for future miscellaneous fill treatments. [ABSTRACT FROM AUTHOR]

The effectiveness of national policies for air pollution control has been demonstrated, but the relative effectiveness of short-term emission reduction measures in comparison with national policies has not. Here we show that short-term abatement measures during important international events substantially reduced PM2.5 concentrations, but air quality rebounded to pre-event levels after the measures ceased. Long-term adherence to strict emission reduction policies led to successful decreases of 54% in PM2.5 concentrations in Beijing, and 23% in atmospheric nitrogen deposition in China from 2012 to 2020. Incentivized by "blue skies" type campaigns, economic development and reactive nitrogen pollution are quickly decoupled, showing that a combination of inspiring but aggressive short-term measures and effective but durable long-term policies delivers sustainable air quality improvement. However, increased ammonia concentrations, transboundary pollutant flows, and the complexity to achieving reduction targets under climate change scenarios, underscore the need for the synergistic control of multiple pollutants and inter-regional action. In response to the rebound of air pollution during large events in China, the authors propose that a combination of ambitious short-term measures and enduring long-term pollution control policies is a sustainable solution for improving air quality. [ABSTRACT FROM AUTHOR]

The construction of new towns is one of the main measures to evacuate urban populations and promote regional coordination and urban–rural integration in China. Mining the spatio-temporal pattern of new town hot spots based on multivariate data and analyzing the influencing factors of new town construction hot spots can provide a strategic basis for new town construction, but few researchers have extracted and analyzed the influencing factors of new town internal hot spots and their classification. In order to define the key points of Wuhan's new town construction and promote the construction of new cities in an orderly and efficient manner, this paper first constructs a space-time cube based on the luminous remote sensing data from 2010 to 2019, extracts hot spots and emerging hot spots in Wuhan New City, selects 14 influencing factor indicators such as population density, and uses bivariate Moran's index to analyze the influencing factors of hot spots, indicating that the number of bus stops and vegetation coverage rate are the most significant. Secondly, the disorderly multivariate logistic regression model is used to analyze the influencing factors of emerging hot spots. The results show that population density, vegetation coverage, road density, distance to water bodies, and distance to train stations are the most significant factors. Finally, based on the analysis results, some relevant suggestions for the construction of Wuhan New City are proposed, providing theoretical support for the planning and policy guidance of new cities, and offering reference for the construction of new towns in other cities, promoting the construction of high-quality cities. [ABSTRACT FROM AUTHOR]

Elevated atmospheric reactive nitrogen (Nr) emissions and the subsequent nitrogen (N) deposition have negatively impacted the global environment, particularly in China. In order to assess the long-term trends in atmospheric N deposition in the south of China, Taojiang County in Hunan Province was selected as a representative rural area for study. We analyzed interannual variation in atmospheric Nr, including gaseous ammonia (NH3), nitrogen dioxide (NO2), nitrate acid (HNO3) vapor, particulate ammonium (NH4+), and nitrate (NO3−) in air and NH4+-N and NO3−-N in precipitation from 2011 to 2020. The 10-year average atmospheric wet-plus-dry N deposition was 41.9 kg N ha−1 yr−1, which decreased by approximately 24% after 2012, indicating that NH3 and NOx emissions were effectively reduced by emission controls introduced in 2013. Wet deposition accounted for approximately 74% of the total N deposition and was significantly influenced by annual precipitation amount. Reduced N (NH3, pNH4+, and NH4+ in rainwater) was the dominant form, comprising approximately 58% of the total N deposition, while oxidized N (pNO3−, NO2, HNO3, and NO3− in rainwater) accounted for 42% of the total N deposition. Atmospheric HNO3, NO2, and NH3 concentrations and deposition declined by 30–80% over the decade, while particulate NH4+ and NO3− concentrations and deposition remained at relatively stable levels, which suggests that ongoing research and policy should focus on rural particulate pollution. Future strategies must concentrate on the integrated control of NH3 and NOx emissions to mitigate air pollution and protect human health, particularly in rural areas because current abatement efforts are primarily directed toward urban areas and the industrial sector, whereas non-point source NH3 pollution, influenced mainly by agricultural activities, dominates in rural regions. [ABSTRACT FROM AUTHOR]