Enhancing soil organic carbon (SOC) sequestration and food supply are vital for human survival when facing climate change. Site‐specific best management practices (BMPs) are being promoted for ...adoption globally as solutions. However, how SOC and crop yield are related to each other in responding to BMPs remains unknown. Here, path analysis based on meta‐analysis and machine learning was conducted to identify the effects and potential mechanisms of how the relationship between SOC and crop yield responds to site‐specific BMPs in China. The results showed that BMPs could significantly enhance SOC and maintain or increase crop yield. The maximum benefits in SOC (30.6%) and crop yield (79.8%) occurred in mineral fertilizer combined with organic inputs (MOF). Specifically, the optimal SOC and crop yield would be achieved when the areas were arid, soil pH was ≥7.3, initial SOC content was ≤10 g kg−1, duration was >10 years, and the nitrogen (N) input level was 100–200 kg ha−1. Further analysis revealed that the original SOC level and crop yield change showed an inverted V‐shaped structure. The association between the changes in SOC and crop yield might be linked to the positive role of the nutrient‐mediated effect. The results generally suggested that improving the SOC can strongly support better crop performance. Limitations in increasing crop yield still exist due to low original SOC level, and in regions where the excessive N inputs, inappropriate tillage or organic input is inadequate and could be diminished by optimizing BMPs in harmony with site‐specific conditions.
BMPs could enhance SOC and maintain or increase crop yield within site‐specific conditions, and the original SOC level and crop yield change showed an inverted V‐shaped structure. The association between them might be linked to the positive of the nutrient‐mediated effect, thus, BMPs should be coordinated and optimized based on site‐specific conditions.
Covalent‐organic frameworks (COFs) have been recognized as a new type of promising photocatalysts for hydrogen evolution. To investigate how different functional groups attached in the backbone of ...COFs affect the overall photocatalytic H2 evolution, for the first time, we selected and synthesized a series of ketoenamine‐based COFs with the same host framework as model system. It includes TpPa−COF−X (X=−H, −(CH3)2, and −NO2) with three different groups attached in the backbone of TpPa−COF. We systematically investigated the differences in morphology, light‐absorption intensity and band gap of these 2D COFs. The results of photocatalytic H2 evolution measurements indicate that the TpPa−COF−(CH3)2 shows the best activity, while the activity of TpPa−COF−NO2 is relatively low compared to that of other two COFs in the system. Moreover, the separation ability of photogenerated charge was also followed the order of TpPa−COF−(CH3)2>TpPa−COF>TpPa−COF−NO2. The best photocatalytic H2 production performance of TpPa−COF−(CH3)2 in these systems should be mainly attributed to the better electron‐donating ability of −CH3 groups compared to −H or −NO2 group, which result in more efficient charge transferring in the inner of the material. This work demonstrates that reasonably adding electron‐donating group in TpPa−COFs can lead to a better photocatalytic H2 evolution activity, and which is meaningful for further design of efficient COF‐based photocatalysts for H2 evolution.
Photocatalysis: A series ketoenamine‐based COFs of TpPa−COF−X (X=−H, −(CH3)2, and −NO2) exhibit significant difference on the visible light absorbance and efficiency of photocatalytic H2 evolution, which can be attributed to strengthen charge carrier mobilities both in‐plane and in the stacking direction because of the electron‐donating groups.
Frequent cyanobacterial blooms in the eutrophic waters produce a variety of toxins such as the monocyclic heptapeptide microcystins, greatly harming aquatic ecosystems and human health. However, ...little information of microcystins in agricultural fields is known. This field study of three common microcystin variants (MC-LR, MC-RR, and MC-YR) in vegetables (n = 161), soils (n = 161) and irrigation water samples (n = 23) collected from southern China regions affected by cyanobacteria blooms, shows their prevalence with total concentrations up to 514 μg/L water, 187 μg/kg soil (dry weight) and 382 μg/kg vegetable (fresh weight). MC-RR was the primary variant in all types of samples, accounting for 51.3–100% of total microcystin concentrations. Significant concentration-dependent correlations (p < 0.05) demonstrated that microcystin-contained irrigation waters were the major source of microcystin accumulation in both vegetables and soils. Meanwhile, intracellular-microcystins in irrigation water was found to play an important role in microcystins bioaccumulation in vegetables for the first time. Most vegetable samples (≥60%), particularly celery posed moderate or high human health risk via diet based on toxicity equivalents of the microcystins and reference dose for MC-LR (0.04 μg/kg/d), showing high food safety hidden dangers. Soil microcystins, especially MC-RR in 46.4–88.3% of soils could pose high ecological risks. This study highlights the potential high ecological and human health risks of microcystins in the real soil-vegetable systems of areas affected by cyanobacteria blooms, implying the profound significance and urgent need of investigation on microcystins in terrestrial ecosystems.
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•MCs are prevalent in actual soil-crop systems affected by cyanobacterial blooms.•MC-RR was the primary variant in all types of the samples.•Intracellular-MCs could play an important role in vegetable MCs accumulation.•Most vegetable samples posed moderate or high human health risk via diet.•Soil MCs, especially MC-RR could pose high ecological risks.
A Pd‐catalyzed enantioselective linear‐allylic alkylation of vinyl benzoxazinanones with a series of 3‐substituted oxindoles was reported in the presence of a chiral oxamide‐phosphine ligand ...(COAP−Bn) under mild reaction conditions. A series of optically active multifunctional 3,3′‐disubstituted oxindole derivatives bearing a quaternary stereogenic center and a linear aryl amino side chain were respectively obtained in 55–98% yields with 96–99% ee for 3‐(hetero)aryl substituted oxindoles. The developed protocol demonstrates that the COAP ligands could serve as a privileged chiral ligand to construct diverse chiral 3,3‐disubstituted oxindole compounds with various quaternary stereogenic centers, such as aza‐, thio‐ or all‐carbon quaternary stereogenic centers. The salient features of the method include broad substrate scope, N‐protecting group free, base‐free, and high regio‐ and enantioselectivity.
The aim of the present study was to investigate the underlying mechanism of AS‐IV and CCN1 in PAH and to evaluate whether the protective effect of AS‐IV against PAH is associated with CCN1 and its ...related signalling pathway. In vivo, male SD rats were intraperitoneally injected with monocrotaline (MCT, 60 mg/kg) or exposed to hypoxia (10% oxygen) and gavaged with AS‐IV (20, 40 and 80 mg/kg/day) to create a PAH model. In vitro, human pulmonary artery endothelial cells (hPAECs) were exposed to hypoxia (3% oxygen) or monocrotaline pyrrole (MCTP, 60 μg/mL) and treated with AS‐IV (10, 20 and 40 μM), EGF (10 nM, ERK agonist), small interfering CCN1 (CCN1 siRNA) and recombinant CCN1 protein (rCCN1, 100 ng/mL). We identified the differences in the expression of genes in the lung tissues of PAH rats by proteomics. At the same time, we dynamically detected the expression of CCN1 by Western blot both in vivo and in vitro. The Western blot experimental results showed that the expression of CCN1 increased in the early stage of PAH and decreased in the advanced stage of PAH. The results showed that compared with the control group, MCT‐ and hypoxia‐induced increased the hemodynamic parameters and apoptosis. AS‐IV can improve PAH, as characterized by decreased hemodynamic parameters, vascular wall area ratio (WA%), vascular wall thickness ratio (WT%) and α‐SMA expression and inhibition of cell apoptosis. Moreover, the improvement of PAH by AS‐IV was accompanied by increased CCN1 expression, which activated the ERK1/2 signalling pathway. Meanwhile, CCN1 and p‐ERK1/2 were inhibited by siCCN1 and promoted by rCCN1. EGF not only activated the ERK1/2 signalling pathway but also induced the expression of CCN1. In conclusion, AS‐IV improves PAH by increasing the expression of CCN1 and activating the ERK1/2 signalling pathway. The results of our study provide a theoretical basis for additional study on the protective effect of AS‐IV against PAH.
Gut microbiota** play important roles in the health and disease status of both humans and animals. Little is known about whether heat stress changes the composition of the gut microbiota in chicken. ...The aim of this study was to investigate the effects of heat stress on changes in caecal microbiota, including changes in growth performance as well as HSP70 and cortisol levels. Sixty 14-day-old female broilers were equally divided into 2 treatment groups with different housing temperatures for 28 D: a control group (C) at 24 to 26°C and a heat stress (HS) group at 34 to 38°C. The caecal contents of the broiler chicken were then extracted on days 1, 3, 7, 14, and 28. Genomic DNA was extracted and amplified based on the V3∼V4 hypervariable region of 16S rRNA high-throughput sequence analyses. The results showed that the average daily gain and average daily feed intake were significantly decreased and that the feed conversion ratio was increased by heat stress. The concentrations of HSP70 and cortisol in the serum were significantly increased. The composition of gut microbiota was influenced by heat stress** through beta diversity analysis and taxon-based analysis. In particular, at the phylum level the composition of Firmicutes, Tenericutes, and Proteobacteria in HS group was increased than that of C group, and Bacteroidetes and Cyanobacteria in HS group were reduced than that of C group. In addition, the composition of Anaeroplasma and Lactobacillus phyla in HS group were increased than that of C group, whereas the Bacteroides, Oscillospira, Faecalibacterium, and Dorea genera in HS group were decreased than that of C group. In conclusion, the gut microbiota in broilers were changed by heat stress. And the changes of the gut microbiota could provide the basis for further research on the heat stress.
Numerical methods are widely used to calculate the secure key rate of many quantum key distribution protocols in practice, but they consume many computing resources and are too time-consuming. In ...this work, we take the homodyne detection discrete-modulated continuous-variable quantum key distribution (CV-QKD) as an example, and construct a neural network that can quickly predict the secure key rate based on the experimental parameters and experimental results. Compared to traditional numerical methods, the speed of the neural network is improved by several orders of magnitude. Importantly, the predicted key rates are not only highly accurate but also highly likely to be secure. This allows the secure key rate of discrete-modulated CV-QKD to be extracted in real time on a low-power platform. Furthermore, our method is versatile and can be extended to quickly calculate the complex secure key rates of various other unstructured quantum key distribution protocols.
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•For the first time, we designed and constructed a series of Ni(OH)2-modified COFs.•Ni(OH)2 acts as noble-metal free cocatalyst in catalyst system.•Ni(OH)2-X%/TpPa-2 photocatalyst is ...comparable to Pt-containing COF-based catalyts.•Ni(OH)2-X%/TpPa-2 photocatalysts master a high rate of electron transport.•The synergistic effect of TpPa-2 and Ni(OH)2 has been systematic studied.
Covalent-organic frameworks (COFs) have been recognized as an emerging type of photocatalysts for H2 evolution and some of them have shown really outstanding photocatalytic activity with the help of Pt co-catalyst. To avoid the utilization of noble metal in COF-based photocatalysts, for the first time, we designed and constructed a series of nickel hydroxide-modified COF (TpPa-2) composite materials Ni(OH)2-X%/TpPa-2 (X: molar fraction of Ni(OH)2), which show apparently improved photocatalytic H2 evolution activity than that of the parent COF and the activity is comparable to that with Pt (0.3 wt%) co-catalyst. A series of Ni(OH)2-X%/TpPa-2 were prepared by in-situ adding TpPa-2 into the reaction system of Ni(OH)2, and the resulting Ni(OH)2-X%/TpPa-2 exhibit a novel sandwich-like morphology. The results of photocatalytic hydrogen evolution under visible light irradiation show that the optimized photocatalytic H2-evolution rate for Ni(OH)2–2.5%/TpPa-2 is up to 1895.99 μmol·h−1·g−1, which is about 26.3 times higher than that of the parent TpPa-2 and is one of the best performing 2D COF-based photocatalyst for H2 evolution. Further investigation confirm the improved activity should be attributed to the enhanced visible-light absorption of the composite materials contributed from Ni(OH)2 and the synergetic effect of Ni(OH)2 and metallic Ni derived from the in-situ reduction of Ni(OH)2, which promoted the separation of photogenerated electron–holes of the resulting materials. This work not only presents a series of new photocatalysts for efficient H2 evolution but also open an avenue for future design and synthesis of COF-based composite materials acting as a substitute of noble-metal-containing photocatalytic systems.
Highlights • In this study, we are the first one to find that the ratio of M1/M2 was significant higher in periodontitis group compared with that in gingivitis one. • In addition, the relative ...expressions of IL-1β and MMP-9 also increased in periodontitis group and was correlated with the ratios of M1/M2. • PD was positively correlated with ratios of M1/M2. • Therefore, analysis of M1/M2 ratio may provide us useful information on the periodontal health status.
Lithium–sulfur (Li–S) batteries as a promising next-generation energy storage device have received increasing attention recently. However, it is still challenging to achieve high sulfur loading and ...high areal capacity in the cathodes. Herein, we design a composite of carbon-wrapped Fe/Fe3C nanoparticles grown in a carbonized melamine sponge (Fe/Fe3C@N-CNT) as a free-standing conductive framework and host scaffold for sulfur loading. High sulfur content up to 86.9 wt% and overall mass loading as high as ∼14.44 mg cm−2 are achieved in the resultant Fe/Fe3C@N-CNT/S composite. A high discharge capacity of 1359 mA h g−1 is delivered for this Fe/Fe3C@N-CNT/S composite at 0.1C, and 561 mA h g−1 is retained after 150 cycles. The high electrochemical performance of this Fe/Fe3C@N-CNT/S composite is attributed to the synergistic effect of Fe/Fe3C nanoparticles, carbon coating, and N-doped carbon nanotubes in the Fe/Fe3C@N-CNT cathode.
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