Search

[Objective] To explore the differences of vegetation growth characteristics between different plant communities and gully positions. [Methods] The vegetation growth characteristics of 5 typical plant communities were systematically studied in Zhifanggou small watershed of Ansai, Shaanxi Province.The investigated characteristics included species diversity, coverage, aboveground biomass, litter storage and underground biomass. [Results] (1) The above ground biomass, litter storage and root reduction coefficient were significantly affected by vegetation type, tree cutting ditch > shrub cutting ditch > herb cutting ditch, and the coverage was shrub cutting ditch > herb cutting ditch > tree cutting ditch. (2) The species diversity index and coverage of the right side of gully (sunny to semi-sunny slopes) were smaller than those on the left side (shade to semi-shade slopes); (3) Under the comprehensive influence of hydrothermal conditions, there was no obvious difference in vegetation growth characteristics between gully bottom and the original slope; (4) The accumulation of litter on the original slope was greater than that of different positions of gully. [Conclusion] The research results provide data foundation and theoretical support for understanding of the potential effects of vegetation restoration on the development of gully and evaluating the role of vegetation in mitigating gully erosion.

A composite coating of magnesium hydroxide/stearic acid on surface of Mg-1Li-1Ca alloy was prepared using vapor diffusion method to improve the corrosion resistance. The surface morphology and chemical composition of the films were characterized by high resolution scanning electron microscopy (HRSEM), Fourier transform infrared spectrometer (FTIR) and X-ray diffraction analysis (XRD). Electrochemical experiments and immersion test were conducted to study corrosion resistance of the obtained composite coating.The formation and degradation mechanisms of the composite coating were proposed.The results show that the magnesium hydroxide coating has a petal-like structure and is well-adhered to the surface of Mg-1Li-1Ca alloy.The stearic acid coating does not change the petal-like structure of the magnesium hydroxide coating. However, the stearic acid can effectively prevent the aggressive medium penetrating into the internal coating due to its low surface energy and good hydrophobicity.The corrosion current density of the magnesium hydroxide/stearic acid (Mg (OH) 2/SA) composite coating (1.45 × 10–7A/cm2) is decreased by two orders of magnitude compared to that of the Mg-1Li-1Ca alloy substrate (2.70 × 10–5 A/cm2), leading to the enhanced corrosion resistance of magnesium alloy.

Given the complex influence of various factors on soil nitrogen (N) and phosphorus (P) loss through runoff in a karst environment, analyzing the importance of different factors to determine the most efficient method for soil nutrient conservation remains a key challenge. Herein, we proposed a novel intelligent analysis strategy based on the Random Forest (RF) regression algorithm to identify the main features and discover the fundamental mechanisms among them under a rock-exposed karst slope with synchronous existence of surface runoff and subsurface leakage. Typically, the results indicated that the rock–soil angle (β) was the main factor influencing soil N and P loss, which was further confirmed based on the RF regression-multifactor analysis. The proposed strategy was used to characterize the relationships of inflow rate, soil bed–ground angle, and rock–soil angle with soil N and P concentrations in soil surface runoff, subsurface runoff, and fissure runoff to study the potential application of soil N and P loss under karst conditions. Our results provide a new approach and promising potential for soil nutrient conservation and related soil and plant research. [ABSTRACT FROM AUTHOR]

Photoactivated sterilization has received more attention in dealing with implant-associated infections due to its advantages of rapid and effective bacteriostasis and broad-spectrum antibacterial activity. Herein, a micro-arc oxidation (MAO)/polymethyltrimethoxysilane (PMTMS)@hemin-induced calcium-bearing phosphate microsphere (Hemin-CaP) coating was prepared on pure magnesium (Mg) via MAO processing and dipping treatments. The morphology and composition of the coating were characterized via scanning electron microscopy, Fourier transform infrared spectrometer, X-ray diffractometer and X-ray photoelectron spectrometer. Corrosion behavior was evaluated through electrochemical and hydrogen evolution tests. The release of Fe3+ ions at different immersion times was measured with an atomic absorption spectrophotometer. Antibacterial performance and cytotoxicity were assessed using the spread plate method, MTT assay and live/dead staining experiment. The results showed that the corrosion current density of the MAO/PMTMS@(Hemin-CaP) coating (4.41 × 10−8 A·cm−2) was decreased by two orders of magnitude compared to that of pure Mg (3.12 × 10−6 A·cm−2). Photoactivated antibacterial efficiencies of the Hemin-CaP microspheres and MAO/PMTMS@(Hemin-CaP) coating reached about 99% and 92%, respectively, which we attributed to the photothermal and photodynamic properties of hemin with a porphyrin ring. Moreover, based on the release of Fe3+ ions, the MC3T3-E1 pre-osteoblasts' viability reached up to 125% after a 72 h culture, indicating a positive effect of the coating in promoting cell growth. Thus, this novel composite coating holds a promising application as bone implants. [ABSTRACT FROM AUTHOR]

Nanocomposites based on Cu2O and Ca‐montmorillonite (Ca+‐MMT) with different composition were successfully prepared via a simple hydrothermal method. The as‐prepared Cu2O‐MMT nanocomposites can rapidly catalytically oxidize the colorless chromogenic substrate, 3,3′,5,5′‐tetramethylbenzydine (TMB) into blue oxTMB with the aid of the H2O2 only in 30 s, which were observed by the naked eye. The reaction catalyzed by the Cu2O‐MMT nanocomposites followed the Michaelis–Menten kinetics. Compared to the MMT or Cu2O alone, Cu2O‐MMT with different mass ratio exhibited an enhanced peroxidase‐like activity. The fabricated H2O2 sensor exhibited a good response to H2O2 with a linear detection range from 3 to 80 μM as well as a detection limit of 2.395 μM. Taking the advantages of the Cu2O‐MMT nanocomposites, including outstanding peroxidase‐like activity and high sensitivity for colorimetric detection of H2O2, a colorimetric sensor based on the Cu2O‐MMT nanocomposites was designed and used to rapidly detect H2O2 in a short time. Cu2O‐MMT nanocomposites can catalytically TMB into blue oxTMB with H2O2 only in 30 s,which were observed by the naked eye. The fabricated H2O2 sensor exhibited a good response to H2O2 with a detection limit of 2.395 μM. [ABSTRACT FROM AUTHOR]