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Exogenous organic carbon (C) inputs and their subsequent microbial and mineral transformation affect the accumulation process of soil organic C (SOC) pool. Nevertheless, knowledge gaps exist on how different long-term forms of crop straw incorporation (direct straw return or pyrolyzed to biochar) modifies SOC composition and stabilization. This study investigated, in a 13-year long-term field experiment, the functional fractions and composition of SOC and the protection of organic C by iron (Fe) oxide minerals in soils amended with straw or biochar. Under the equal C input, SOC accumulation was enhanced with both direct straw return (by 43%) and biochar incorporation (by 85%) compared to non-amended conventional fertilization, but by different pathways. Biochar had greater efficiency in increasing SOC through stable exogenous C inputs and inhibition of soil respiration. Moreover, biochar-amended soils contained 5.0-fold greater SOCs in particulate organic matter (POM) and 1.2-fold more in mineral-associated organic matter (MAOM) relative to conventionally fertilized soils. Comparatively, although the magnitude of the effect was smaller, straw-derived OC was preserved preferentially the most in the MAOM. Straw incorporation increased the soil nutrient content and stimulated the microbial activity, resulting in greater increases in microbial necromass C accumulation in POM and MAOM (by 117% and 43%, respectively) compared to biochar (by 72% and 18%). Moreover, straw incorporation promoted poorly crystalline (Feo) and organically complexed (Fep) Fe oxides accumulation, and both were significantly and positively correlated with MAOM and SOC. The results address the decadal-scale effects of biochar and straw application on the formation of the stable organic C pool in soil, and understanding the causal mechanisms can allow field practices to maximize SOC content. These results are of great implications for better predicting and accurately controlling the response of SOC pools in agroecosystems to future changes and disturbances and for maintaining regional C balance. [ABSTRACT FROM AUTHOR]

A novel 2D/2D g-C3N4/BiOCl (CN/BOC) heterojunction photocatalyst was synthesized by grinding appropriate amounts of CN, Bi(NO3)3·5H2O, glacial acetic acid and KCl at room temperature. The porous CN nanosheets not only facilitate the in situ nucleation and growth of BOC to form thin nanosheets and constitute an intimate contact interface, but also introduce more oxygen vacancies (OVs) in the grinding process. The 2D/2D CN/BOC heterojunction had a good interface and generates a built-in electric field, which can improve the separation of e− and h+. The synergistic effect of the heterostructure and OVs made the photocatalyst have significantly better performance than CN and BOC alone under visible light. The most efficient CN/BOC-5 could achieve a tetracycline (TC) degradation rate of 89.8% within 2 h, which was 1.9 and 1.2 times faster than CN and BOC, respectively. It catalyzed the reduction of CO2 to CO at a rate of 2.00 μ mol h−1 g−1, 1.1 and 3.2 times faster than CN and BOC, respectively. The mechanism for the photocatalysis of CN/BOC-5 was revealed. It was confirmed that the efficiency of photo-induced carrier separation and visible-light photo-absorption were both considerably increased by the synergistic interaction between OVs and 2D/2D heterojunction. This research may open up new possibilities for the logical design of efficient photocatalysts through combining 2D/2D heterojunctions with OVs for environmental remediation. Highlights: •Grinding synthesis of 2D/2D BiOCl/g-C3N4 heterostructure with oxygen vacancies (OVs). •The synergistic effect of heterostructure and OVs enabled excellent photoactivity. •Efficient photocatalytic degradation of organic pollutants and reduction of CO2. [ABSTRACT FROM AUTHOR]

Copyrolysis biochar derived from rape straw (RSBC) was prepared through oxygen-limited pyrolysis at 500 °C and utilized to investigate its adsorption capability for single and complex trace elements (Fe2+, Mn2+, Cu2+, and Zn2+) in contaminated solutions. The microstructures, functional groups, and adsorption behaviors of RSBC were determined through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and batch adsorption experiments, respectively. From these, the single/complex adsorption results showed that the adsorption capacity of RSBC for Fe2+, Mn2+, Cu2+, and Zn2+ was 32.21/23.78, 8.95/3.41, 28.12/7.19, and 13.77/4.92 mg/g, respectively. The Langmuir isotherm model fit better than that of Freundlich in the mixed adsorption system, while the pseudo-second-order kinetic model was the most suitable for single adsorption. Thermodynamic adsorption analysis revealed that the removal rate of the four ions by RSBC was 22.14%, 8.95%, 18.75%, and 13.77%, respectively. Moreover, the adsorption mechanism was primarily chemical adsorption, including ion exchange, precipitation, and complexation, because of the binding effects of aromatic structures and polar groups. Additionally, biochar, with its porous structure and high ash content also provided favorable conditions for adsorption of those ions. Through this simple procedure, this work provides a potential strategy to produce biochar with a high adsorption capacity to remediate trace elements in contaminated solutions. [ABSTRACT FROM AUTHOR]

Aims/Introduction: Blockade or reversal the progression of diabetic nephropathy is a clinical challenge. The aim of the present study was to examine whether recombinant human glucagon‐like peptide‐1 (rhGLP‐1) has an effect on alleviating urinary protein and urinary albumin levels in diabetic rats. Materials and Methods: Streptozotocin‐induced diabetes rats were treated with rhGLP‐1 insulin and saline. Using immunostaining, hematoxylin–eosin, electron microscopy and periodic acid–Schiff staining to study the pathology of diabetic nephropathy, and we carried out quantitative reverse transcription polymerase chain reaction, western blot and immunohistochemistry to identify the differentially expressed proteins. The mechanism was studied through advanced glycation end‐products‐induced tubular epithelial cells. Results: rhGLP‐1 inhibits protein kinase C (PKC)‐β, but increases protein kinase A (PKA), which reduces oxidative stress in glomeruli and in cultured glomerular microvascular endothelial cells. In tubules, rhGLP‐1 increased the expression of two key proteins related to re‐absorption – megalin and cubilin – which was accompanied by downregulation of PKC‐β and upregulation of PKA. On human proximal tubular epithelial cells, rhGLP‐1 enhanced the absorption of albumin, and this was blocked by a PKC activator or PKA inhibitor. Conclusions: These findings suggest that rhGLP‐1 can reverse diabetic nephropathy by protecting both glomeruli and tubules by inhibiting PKC and activating PKA. [ABSTRACT FROM AUTHOR]