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Green manure is a crucial strategy for increasing cereal yield and mitigating environmental burden while reducing chemical N fertilizer. To effectively tackle climate change, finding ways to reduce nitrous oxide (N2O) emissions from green manuring systems is vital. Herein, field and 15N labeled microcosm experiments were arranged to investigate the effect and mechanisms of green manuring and zeolite application on N2O emission. Both experiments comprised four treatments: conventional chemical N (N100), 70â¯% chemical N (N70), N70 with green manure (N70â¯+â¯CV), and N70â¯+â¯CV combined with zeolite (N70â¯+â¯CVâ¯+â¯Z). Compared with N100, both N70â¯+â¯CV and N70â¯+â¯CVâ¯+â¯Z maintained maize yield, cumulative N2O emissions decreased by 37.7â¯% and 34.9â¯% in N70â¯+â¯CVâ¯+â¯Z in 2022-yr and 2023-yr, and by 12.8â¯% in N70â¯+â¯CV in 2022-yr. Moreover, the reduction of N2O emission primarily occurred after incorporating green manure. The N100 and N70â¯+â¯CV demonstrated a similar transformed proportion of chemical N to N2O (i.e., 4.9â¯% and 4.7â¯%) while reducing it to 2.7â¯% in N70â¯+â¯CVâ¯+â¯Z. Additionally, a mere 0.7â¯% of green manure N was transformed to N2O in both N70â¯+â¯CV and N70â¯+â¯CVâ¯+â¯Z treatments. Compared with N100, both N70â¯+â¯CV and N70â¯+â¯CVâ¯+â¯Z decreased the relative abundances of ammonia oxidation microbes, increased denitrifier and the ratios of (nirKâ¯+â¯nirS)/nosZ and norBC/nosZ. Furthermore, compared with N70â¯+â¯CV, N70â¯+â¯CVâ¯+â¯Z decreased the relative abundances of N2O-producer and the ratios of (nirKâ¯+â¯nirS)/nosZ and norBC/nosZ in denitrification. These findings revealed that the reduction of N2O emissions resulting from green manure replaced chemical N was mainly due to weakened nitrification, while zeolite reduced N2O emissions attributed to enhanced conversion of N2O to N2. Moreover, certain key N-cycling functional bacteria, such as Phycisphaerae, Rubrobacteria, and Thermoflexia, were positively correlated with N2O emission. In contrast, Dehalococcoidia, Gammaproteobacteria, and Betaproteobacteria were negatively correlated with N2O emission. This investigation uncovered the underlying mechanisms for effectively reducing N2O emissions through green manure combined with zeolite.
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Cadmium (Cd) in paddy soil poses significant risks to humans due to its strong biological migration and toxicity. Chinese milk vetch (MV) is commonly used as green manure in the paddy fields of southern China and its potential to decrease the availability of Cd has been identified. Nevertheless, the effects of MV combined with lime materials (lime, L; limestone, LS) on Cd availability, soil properties, enzyme activity and comprehensive benefits are still not fully understood in double-cropping rice system. A field study was conducted to investigate these changes. The results indicated that all treatments notably decreased soil available Cd (Avail-Cd) by 19.3-44.3% and 14.9-43.1% during early and late rice, compared with CK. Moreover, the Cd fractions transformed to more stable forms. Compared to CK, all treatments reduced brown rice Cd content by 34.6-64.2% and 12.7-52.5% during the two periods. Furthermore, the translocation factors root to shoot, as well as shoot to brown rice, decreased. The combination led to improvements in soil properties, soil enzyme activity. Meantime, Cd in iron-manganese plaque (IMP) decreased by 31.9-51.1% and 29.0-42.7% respectively during two periods in amendments treatments. Soil pH and DOC were more important factors for Cd bioavailability than other properties. Additionally, rice Cd uptake was positively correlated with Cd in IMP. Enzyme activity exhibited a negative correlation with soil active Cd. Partial Least Squares Path Model (PLS-PM) indicated that the mitigation of Cd pollution helped to improve soil enzyme activity. Grey correlation analysis (GRA) indicated that MVLS showed the best comprehensive benefits in soil-plant system. Overall, the combination of MV and lime materials could reduce Cd availability, enhance soil properties and enzyme activity. And this could be strengthened by the combination. These findings will provide valuable insights for Cd-contaminated soil remediation.
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Green manure with appropriate amount of chemical nitrogen fertilizer can increase crop yield, but also aggravate soil carbon emissions. However, it is unclear whether incorporation of green manure into the cropping pattern with reduced nitrogen amount can alleviate this situation and enhance carbon sequestration potential. So, a field experiment with split-plot design was set up in 2018 of northwest China, and studied the effects of nitrogen reduction on crop productivity, carbon emissions, and carbon sequestration potential in 2021-2023. The main plots were two cropping patterns, including multiple cropped green manure after wheat harvest (W-G) and fallow after wheat harvest (W). Three nitrogen application levels formed the split-plots, including local conventional nitrogen amount (N3, 180 kg ha-1), nitrogen amount reduced by 15% (N2, 153 kg ha-1) and 30% (N3, 126 kg ha-1). The results showed that W-G increased grain yield of wheat and energy yield of wheat multiple cropped green manure pattern. The multiple cropped green manure after wheat harvest with local conventional nitrogen amount reduced by 15% (W-GN2) had the significant increasing-effect, and increased grain yield of wheat by 9.6% and increased total energy yields by 39.3% compared to fallow after wheat harvest with local conventional nitrogen amount (W-N3). Relative to W-N3, W-GN2 did not significantly increase carbon emissions of wheat season, and increased total carbon emissions of cropping pattern by 11.1%. Compared to multiple cropped green manure after wheat harvest with local conventional nitrogen amount (W-GN3), W-GN2 decreased carbon emissions by 5.8% in wheat season and decreased by 3.9% in the whole cropping pattern. Therefore, W-GN2 gained high carbon emission efficiency based on grain yield, and were 9.9% and 11.2% higher than W-N3 and W-GN3, respectively. In addition, W-GN2 enhanced soil total nitrogen, carbon, and organic carbon contents, compared with W-N3, thus increasing soil carbon sequestration potential index (net primary productivity/carbon emissions). We conclude that multiple cropped leguminous green manure after wheat harvest with local conventional nitrogen amount reduced by 15% can enhance crop productivity and carbon sequestration potential of farmland in arid areas.
Sujet(s)
Séquestration du carbone , Production végétale , Engrais , Fumier , Azote , Sol , Triticum , Triticum/croissance et développement , Triticum/métabolisme , Azote/métabolisme , Azote/analyse , Production végétale/méthodes , Sol/composition chimique , Chine , Carbone/métabolisme , Produits agricoles/croissance et développement , AgricultureRÉSUMÉ
Stone matrix asphalt and asphalt concrete mixture with 13.2 mm nominal maximum aggregate size (named SMA13 and AC13, respectively) are widely used in the surface course of asphalt pavement in China. Generally, the pavement performance of SMA13 is superior to that of AC13, while the cost of the former is significantly higher than that of the latter. The objective of this paper was to develop a new hot mix asphalt (named SMAC13) whose performance and cost are between SMA13 and AC13. A boundary sieve size (BSS) of 2.36 mm was selected between fine and coarse aggregates. Based on the union set of aggregate gradation ranges of SMA13 and AC13, the family of gradation curves in the forms of S shapes were designed in terms of the BSS passing rate. According to the evaluation of the skeleton interlock of coarse aggregate of the gradation curve family, the aggregate gradation range of SMAC13 was determined. Also, the performance of three kinds of asphalt mixtures were compared through laboratory tests. The results indicated that SMA13 shows the best rutting resistance, followed by SMAC13 then AC13, while in terms of low-temperature performance in resistance to cracking, the sequence is SMAC13, AC13, and SMA13. The sequence of water stability is AC13, SMAC13, and SMA13. Furthermore, the cost of SMAC13 is 25% less than that of SMA13. Therefore, SMAC13 can be used as an alternative for the surface course of asphalt pavement in terms of performance and cost.
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Manganese(II)-based contrast agents (MBCAs) are potential candidates for gadolinium-free enhanced magnetic resonance imaging (MRI). In this work, a rigid binuclear MBCA (Mn2-PhDTA2) with a zero-length linker was developed via facile synthetic routes, while the other dimer (Mn2-TPA-PhDTA2) with a longer rigid linker was also synthesized via more complex steps. Although the molecular weight of Mn2-PhDTA2 is lower than that of Mn2-TPA-PhDTA2, their T1 relaxivities are similar, being increased by over 71% compared to the mononuclear Mn-PhDTA. In the presence of serum albumin, the relaxivity of Mn2-PhDTA2 was slightly lower than that of Mn2-TPA-PhDTA2, possibly due to the lower affinity constant. The transmetalation reaction with copper(II) ions confirmed that Mn2-PhDTA2 has an ideal kinetic inertness with a dissociation half-life of approximately 10.4 h under physiological conditions. In the variable-temperature 17O NMR study, both Mn-PhDTA and Mn2-PhDTA2 demonstrated a similar estimated q close to 1, indicating the formation of monohydrated complexes with each manganese(II) ion. In addition, Mn2-PhDTA2 demonstrated a superior contrast enhancement to Mn-PhDTA in in vivo vascular and hepatic MRI and can be rapidly cleared through a dual hepatic and renal excretion pattern. The hepatic uptake mechanism of Mn2-PhDTA2 mediated by SLC39A14 was validated in cellular uptake studies.
Sujet(s)
Produits de contraste , Foie , Imagerie par résonance magnétique , Manganèse , Manganèse/composition chimique , Foie/imagerie diagnostique , Foie/métabolisme , Imagerie par résonance magnétique/méthodes , Animaux , Produits de contraste/composition chimique , Produits de contraste/synthèse chimique , Humains , Transporteurs de cations/métabolisme , Transporteurs de cations/composition chimique , Souris , Complexes de coordination/composition chimique , Complexes de coordination/synthèse chimiqueRÉSUMÉ
The use of green manure can substantially increase the microbial diversity and multifunctionality of soil. Green manuring practices are becoming popular for tobacco production in China. However, the influence of different green manures in tobacco fields has not yet been clarified. Here, smooth vetch (SV), hairy vetch (HV), broad bean (BB), common vetch (CV), rapeseed (RS), and radish (RD) were selected as green manures to investigate their impact on soil multifunctionality and evaluate their effects on enhancing soil quality for tobacco cultivation in southwest China. The biomass of tobacco was highest in the SV treatment. Soil pH declined, and soil organic matter (SOM), total nitrogen (TN), and dissolved organic carbon (DOC) content in CV and BB and activity of extracellular enzymes in SV and CV treatments were higher than those in other treatments. Fungal diversity declined in SV and CV but did not affect soil multifunctionality, indicating that bacterial communities contributed more to soil multifunctionality than fungal communities. The abundance of Firmicutes, Rhizobiales, and Micrococcales in SV and CV treatments increased and was negatively correlated with soil pH but positively correlated with soil multifunctionality, suggesting that the decrease in soil pH contributed to increases in the abundance of functional bacteria. In the bacteria-fungi co-occurrence network, the relative abundance of key ecological modules negatively correlated with soil multifunctionality and was low in SV, CV, BB, and RS treatments, and this was associated with reductions in soil pH and increases in the content of SOM and nitrate nitrogen (NO3--N). Overall, we found that SV and CV are more beneficial for soil multifunctionality, and this was driven by the decrease in soil pH and the increase in SOM, TN, NO3--N, and C- and N-cycling functional bacteria.
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The potential nutrient uptake abilities of a plant are essential for improving the yield and quality. Green manures can take up a huge amount of macronutrients from the soil. The mechanisms underlying the differences in nutrient uptake capacity among different nonlegume species remain unclear. The plot experiments were conducted to investigate the performance of nonlegume species including forage radish (Raphanus raphanistrum subsp. sativus), oil radish (Raphanus sativus var. Longipinnatus), February orchid (Orychophragmus violaceus L), and rapeseed (Baricca napus), while a ryegrass (Lolium perenne L.) species was used as a control. The study results showed that forage radish had the highest nutrient uptake (N and P), i.e., 322 and 101% in Hunan and 277 and 469% in the Sichuan site, respectively, compared with the control. While the greatest K uptake was found in forage radish, i.e., 123%, and February orchid, 243%, in the Hunan and Sichuan sites. Forage radish also presented higher phosphorus use efficiency in both experimental areas: Hunan by 301% and Sichuan by 633% compared to the control. Significant modifications were found in nutrient availability and enzyme activities after the cultivation of various species. The oil radish enhanced the ß-glucosidase (BG) and leucine-aminopeptidase enzyme activities by 324 and 367%, respectively, while forage radish developed the highest phosphatase (Phase) and N-acetyl-glucosaminidase (NAG) activities compared to the ryegrass in Hunan. In the Sichuan site, the oil radish promotes enzyme activities such as Phase (126%), BG (19%), and NAG (17%), compared to the control. It is concluded that forage radish, oil radish, and February orchid can easily improve soil nutrient quality in green manuring practices and provide valuable nutrient management systems.
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BACKGROUND: Managing residual and recurrent craniopharyngioma effectively is crucial for improving patient outcomes. This study evaluates the combined use of gamma knife and phosphorus-32 brachytherapy, offering insights into alternative, less invasive treatment strategies. METHODS: We conducted a retrospective analysis of 97 patients treated from 2010 to 2016 for residual and recurrent craniopharyngioma using gamma knife and phosphorus-32 brachytherapy. We classified these patients into three groups: superficial solid (Group A), simple cystic (Group B), and mixed cystic-solid (Group C). We assessed the treatment's effectiveness by the tumor control rates and evaluated safety by monitoring vision, endocrine function improvements, and complication rates. RESULTS: The treatment achieved complete and adequate control rates of 49.5% and 87.6%, respectively. We observed improvements in vision or visual fields in 55.1% of the patients. The morbidity rate was 15.5%. The study found no significant differences in tumor control rates among the various lesion types. CONCLUSION: The combination of gamma knife and phosphorus-32 brachytherapy presents a viable, minimally invasive alternative for treating residual and recurrent craniopharyngioma. It offers high tumor control and functional improvement rates, suggesting its potential as a preferred strategy in some instances.
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Effective vascular and hepatic enhancement and better safety are the key drivers for exploring gadolinium-free hepatobiliary contrast agents. Herein, a facile strategy proposes that the high lipophilicity may be favorable to enhancing sequentially vascular and hepatobiliary signal intensity based on the structure-activity relationship that both hepatic uptake and interaction with serum albumins partly depend on lipophilicity. Therefore, 11 newly synthesized derivatives of manganese o-phenylenediamine-N,N,N',N'-tetraacetic acid (MnLs) were evaluated as vascular and hepatobiliary agents. The maximum signal intensities of the heart, liver, and kidneys were strongly correlated with log P, a key indicator of lipophilicity. The most lipophilic agent, MnL6, showed favorable relaxivity when binding with serum albumin, good vascular enhancement, rapid excretion, and reliable hepatobiliary phases comparable to a classic hepatobiliary agent, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) for in vivo liver tumor imaging. Inhibition experiments confirmed the hepatic targeting of MnL6 is mediated by organic anion-transporting polypeptides.
Sujet(s)
Produits de contraste , Tumeurs du foie , Humains , Produits de contraste/métabolisme , Manganèse , Acide gadopentétique/métabolisme , Foie/métabolisme , Tumeurs du foie/anatomopathologie , Imagerie par résonance magnétique/méthodesRÉSUMÉ
In southern China, winter green manure is widely used in rice cropping systems for improving grain yields and soil fertility. Cd pollution has recently been reported in some of these paddy fields. Research on the in-depth understanding of how green manuring affects Cd absorption in rice is limited. This study aimed to investigate the impacts of different green manures, including single plantation and mixed plantation on the absorption of Cd by rice and explore the underlying mechanisms. Pot experiments demonstrated that compared with winter fallow-rice, green manuring treatments considerably decreased rice Cd content, promoted the conversion of bioavailable Cd fraction into a more stable form, induced the formation of iron plaque, and increased the content of humic-like fraction (HF) in soil dissolved organic matter (DOM). Treatment with mixed plantation resulted in a greater decrease in rice Cd content and an increase in HF and iron plaque contents than single plantation. Hydroponic experiments confirmed that both iron plaque and green manure-derived DOM significantly reduced the Cd content in rice seedlings. In conclusion, green manure incorporation is an efficient measure for the safe utilization of Cd-contaminated soil, and mixed plantation of different green manures exerts stronger effects.
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Cadmium , Fer , Fumier , Oryza , Polluants du sol , Oryza/métabolisme , Oryza/croissance et développement , Cadmium/analyse , Cadmium/métabolisme , Fer/métabolisme , Polluants du sol/analyse , Polluants du sol/métabolisme , Fumier/analyse , Chine , Agriculture/méthodes , Substances humiques/analyse , Sol/composition chimiqueRÉSUMÉ
Molybdenum disulfide (nano-MoS2) nanomaterials have shown great potential for biomedical and catalytic applications due to their unique enzyme-mimicking properties. However, their potential agricultural applications have been largely unexplored. A key factor prior to the application of nano-MoS2 in agriculture is understanding its behavior in a complex soil-plant system, particularly in terms of its transformation. Here, we investigate the distribution and transformation of two types of nano-MoS2 (MoS2 nanoparticles and MoS2 nanosheets) in a soil-soybean system through a combination of synchrotron radiation-based X-ray absorption near-edge spectroscopy (XANES) and single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS). We found that MoS2 nanoparticles (NPs) transform dynamically in soil and plant tissues, releasing molybdenum (Mo) and sulfur (S) that can be incorporated gradually into the key enzymes involved in nitrogen metabolism and the antioxidant system, while the rest remain intact and act as nanozymes. Notably, there is 247.9 mg/kg of organic Mo in the nodule, while there is only 49.9 mg/kg of MoS2 NPs. This study demonstrates that it is the transformation that leads to the multifunctionality of MoS2, which can improve the biological nitrogen fixation (BNF) and growth. Therefore, MoS2 NPs enable a 30% increase in yield compared to the traditional molybdenum fertilizer (Na2MoO4). Excessive transformation of MoS2 nanosheets (NS) leads to the overaccumulation of Mo and sulfate in the plant, which damages the nodule function and yield. The study highlights the importance of understanding the transformation of nanomaterials for agricultural applications in future studies.
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Nanostructures , Sol , Sol/composition chimique , Glycine max , Molybdène , AgricultureRÉSUMÉ
Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especially after decades of fertilization. Here, we assess the contribution of the soil functionalities of carbon (C), nitrogen (N), and phosphorus (P) cycling to crop production and explore how soil organisms control these functionalities in a 33-year field fertilization experiment. The long-term application of green manure or cow manure produced wheat yields equivalent to those obtained with chemical N, with the former providing higher soil functions and allowing the functionality of N cycling (especially soil N mineralization and biological N fixation) to control wheat production. The keystone phylotypes within the global network rather than the overall microbial community dominated the soil multifunctionality and functionality of C, N, and P cycling across the soil profile (0-100 cm). We further confirmed that these keystone phylotypes consisted of many metabolic pathways of nutrient cycling and essential microbes involved in organic C mineralization, N2O release, and biological N fixation. The chemical N, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48 genes and Nitrosomonadaceae, Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N2O release, N fixation, and organic C mineralization, respectively. Moreover, our results demonstrated that organic fertilization increased the effects of the network size and keystone phylotypes on the subsoil functions by facilitating the migration of soil microorganisms across the soil profiles and green manure with the highest migration rates. This study highlights the importance of the functionality of N cycling in controlling crop production and keystone phylotypes in regulating soil functions, and provides selectable fertilization strategies for maintaining crop production and soil functions across soil profiles in agricultural ecosystems.
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Microbiote , Sol , Sol/composition chimique , Fumier , Azote/métabolisme , Agriculture/méthodes , Grains comestibles/métabolisme , Engrais/analyse , Microbiologie du solRÉSUMÉ
This study aimed to investigate the effects of ulinastatin on the apoptosis and (Sirt1/FoxO3a) pathway of vascular smooth muscle cells (VSMC) in aortic dissection (AD) rats. For this purpose a rat model of aortic dissection (AD) was constructed by giving drinking water containing 0.08% ß-aminopropionitrile (BAPN) to rats, HE staining was used to observe the pathological changes of the aorta in AD rats; the diseased blood vessels of AD rats were taken for primary culture and passage of VSMCs, the morphology of VSMCs was observed, and VSMCs were identify with immunofluorescence staining; VSMCs were treated with culture media containing 0, 1000, 2000, 3000, 4000, 5000, 6000, 7000 U/mL ulinastatin, and MTT kit was used to determine the effect of ulinastatin on VSMC proliferation in AD rats; the VSMC of AD rats were divided into blank group (normal culture), ulinastatin group (medium containing 5000 U/mL ulinastatin), Sirt1 inhibitor group (medium containing 1 µmol/L EX527), ulinastatin + Sirt1 inhibitor group (medium containing 5000 U/mL ulinastatin, 1 µmol/L EX527), flow cytometry was used to detect the VSMC apoptosis in each group, WB was used to detect the expression of VSMC apoptosis-related proteins and Sirt1/FoxO3a pathway-related proteins in each group. Findings suggested that the aortic wall of AD rats was thickened, and the dissection false cavity appeared; VSMC mostly presented different shapes such as triangles and stars, the immunofluorescence staining results showed that α-SMA was arranged in the cytoplasm in the form of myofilaments, showing green fluorescence, and the nucleus showed blue fluorescence, and the rate of positive cells was more than 95%; various doses of ulinastatin had a certain inhibitory effect on the proliferation of VSMC, and 5000 U/mL ulinastatin had a higher proliferation inhibition rate; compared with the blank group, the VSMC apoptosis rate, Caspase-3, Bax protein, Sirt1/FoxO3a pathway related protein expression in the ulinastatin group were significantly increased, and the Bcl-2 protein expression was significantly decreased (P<0.05), the VSMC apoptosis rate, Caspase-3, Bax protein, Sirt1/FoxO3a pathway related protein expression in the Sirt1 inhibitor group were significantly decreased, and the Bcl-2 protein expression was significantly increased (P<0.05); compared with the ulinastatin group, the VSMC apoptosis rate, Caspase-3, Bax protein, Sirt1/FoxO3a pathway related protein expression in the ulinastatin + Sirt1 inhibitor group were significantly decreased, and the Bcl-2 protein expression was significantly increased (P<0.05). It was concluded that ulinastatin can inhibit the proliferation of VSMCs in AD rats and promote their apoptosis, which may be achieved by activating the Sirt1/FoxO3a pathway.
Sujet(s)
, Muscles lisses vasculaires , Rats , Animaux , Protéine Bax/métabolisme , Caspase-3/métabolisme , Sirtuine-1/métabolisme , Apoptose , Protéines proto-oncogènes c-bcl-2/métabolisme , Myocytes du muscle lisseRÉSUMÉ
Milk vetch (Astragalus sinicus L.) is leguminous green manure (GM) which produces organic nitrogen (N) for subsequent crops and is widely planted and utilized to simultaneously reduce the use of synthetic N fertilizer and its environmental costs in rice systems. Determination of an optimal N application rate specific to the GM-rice system is challenging because of the large temporal and spatial variations in soil, climate, and field management conditions. To solve this problem, we developed a framework to explore the site-specific N application rate for the low-N footprint rice production system in southern China based on multi-site field experiments, farmer field survey, and process-based model (WHCNS_Rice, soil water heat carbon nitrogen simulator for rice). The results showed that a process-based model can explain >83.3% (p < 0.01) of the variation in rice yield, aboveground biomass, crop N uptake, and soil mineral N. Based on the scenario analysis of the tested WHCNS_Rice model, the simple regression equation was developed to implement site-specific N application rates that considered variations in GM biomass, soil, and climatic conditions. Simulation evaluation on nine provinces in southern China showed that the site-specific N application rate reduced regional synthetic N fertilizer input by 29.6 ± 17.8% and 65.3 ± 23.0% for single and early rice, respectively; decreased their total N footprints (NFs) by 23.4% and 49.3%, respectively; and without reduction in rice yield, compared with traditional farming N practices. The reduction in total NF was attributed to the reduced emissions from ammonia volatilization by 35.2%, N leaching by 28.4%, and N runoff by 32.7%. In this study, we suggested a low NF rice production system that can be obtained by combining GM with site-specific N application rate in southern China.
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Oryza , Fumier/analyse , Engrais/analyse , Production végétale/méthodes , Agriculture/méthodes , Sol , Chine , Azote/analyseRÉSUMÉ
Considerable efforts have been made to develop nanoparticle-based magnetic resonance contrast agents (CAs) with high relaxivity. The prolonged rotational correlation time (τR) induced relaxivity enhancement is commonly recognized, while the effect of the water coordination numbers (q) on the relaxivity of nanoparticle-based CAs gets less attention. Herein, we first investigated the relationship between T1 relaxivity (r1) and q in manganese-based hybrid micellar CAs and proposed a strategy to enhance the relaxivity by increasing q. Hybrid micelles with different ratios of amphiphilic manganese complex (MnL) and DSPE-PEG2000 were prepared, whose q values were evaluated by Oxygen-17-NMR spectroscopy. Micelles with lower manganese doping density exhibit increased q and enhanced relaxivity, corroborating the conception. In vivo sentinel lymph node (SLN) imaging demonstrates that DSPE-PEG/MnL micelles could differentiate metastatic SLN from inflammatory LN. Our strategy makes it feasible for relaxivity enhancement by modulating q, providing new approaches for the structural design of high-performance hybrid micellar CAs.
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Micelles , Eau , Manganèse/composition chimique , Lymphographie , Imagerie par résonance magnétique/méthodes , Spectroscopie par résonance magnétique , Produits de contraste/composition chimiqueRÉSUMÉ
PURPOSE: The ophthalmic artery is often involved in suprasellar and parasellar surgeries, but the anatomical structure where the ophthalmic artery originates has not been fully clarified from the perspective of an endoscopic endonasal approach (EEA). METHODS: A total of 10 fresh cadaveric heads (20 sides) were dissected through an EEA, and the origin of the bilateral ophthalmic arteries and their adjacent structures were observed from a ventral view. The origin of the ophthalmic artery in 50 healthy people was retrospectively studied on computed tomography angiography imaging. RESULTS: The ophthalmic artery originated from the intradural segment (75%), paraclinoid segment (15%), or parasellar segment (10%) of the internal carotid artery. The cross-sectional view of the internal carotid artery through the EEA showed that the ophthalmic artery originated from the middle 1/3 (75%) or medial 1/3 (25%) of the upper surface of the internal carotid artery. On computed tomography angiography, the ophthalmic artery originated from the middle 1/3 (77%) and medial 1/3 (22%) of the upper surface of the internal carotid artery. All ophthalmic arteries were near the level of the distal dural ring (DDR) of the internal carotid artery, that is, within 3 mm above or below the DDR. CONCLUSIONS: The ophthalmic artery usually originates in the middle 1/3 of the upper surface of the intradural segment of the internal carotid artery within 3 mm of the DDR. The ophthalmic artery can be protected to the utmost extent after its origin is identified through an EEA.
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The prevalence of chronic kidney disease (CKD) has been increasing over the past decades. However, no effective therapies are available for delaying or curing CKD. Progressive fibrosis is the major pathological feature of CKD, which leads to end-stage renal disease (ESRD). The present study showed that Polo-like kinase 1 (Plk1) was upregulated in the kidneys of CKD patients and mice subjected to unilateral ureteral obstruction (UUO) with location in proximal tubules and tubulointerstitial fibroblasts. Pharmacological inhibition, genetic silencing or knockout of Plk1 attenuated obstructive nephropathy due to suppressed fibroblast activation mediated by reduced autophagic flux. We found Plk1 plays a critical role in maintaining intralysosomal pH by regulating ATP6V1A phosphorylation, and inhibition of Plk1 impaired lysosomal function leading to blockade of autophagic flux. In addition, Plk1 also prevented partial epithelial-mesenchymal transition (pEMT) of tubular epithelial cells via autophagy pathway. In conclusion, this study demonstrated that Plk1 plays a pathogenic role in renal tubulointerstitial fibrosis by regulating autophagy/lysosome axis. Thus, targeting Plk1 could be a promising strategy for CKD treatment.
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Protein-Serine-Threonine Kinases , Insuffisance rénale chronique , Animaux , Souris , Protein-Serine-Threonine Kinases/génétique , Protéines du cycle cellulaire/génétique , Insuffisance rénale chronique/génétique , Autophagie/génétique ,RÉSUMÉ
Soybean (Glycine max) is a crop of global significance and has low reliance on N fertilizers due to its biological nitrogen fixation (BNF) capacity, which harvests ambient N2 as a critical ecosystem service. BNF can be severely compromised by abiotic stresses. Enhancing BNF is increasingly important not only to alleviate global food insecurity but also to reduce the environmental impact of agriculture by decreasing chemical fertilizer inputs. However, this has proven challenging using current genetic modification or bacterial nodulation methods. Here, we demonstrate that a single application of a low dose (10 mg/kg) of molybdenum disulfide nanoparticles (MoS2 NPs) can enhance soybean BNF and grain yield by 30%, compared with conventional molybdate fertilizer. Unlike molybdate, MoS2 NPs can more sustainably release Mo, which then is effectively incorporated as a cofactor for the synthesis of nitrogenase and molybdenum-based enzymes that subsequently enhance BNF. Sulfur is also released sustainably and incorporated into biomolecule synthesis, particularly in thiol-containing antioxidants. The superior antioxidant enzyme activity of MoS2 NPs, together with the thiol compounds, protect the nodules from reactive oxygen species (ROS) damage, delay nodule aging, and maintain the BNF function for a longer term. The multifunctional nature of MoS2 NPs makes them a highly effective strategy to enhance plant tolerance to abiotic stresses. Given that the physicochemical properties of nanomaterials can be readily modulated, material performance (e.g., ROS capturing capacity) can be further enhanced by several synthesis strategies. This study thus demonstrates that nanotechnology can be an efficient and sustainable approach to enhancing BNF and crop yield under abiotic stress and combating global food insecurity.
Sujet(s)
Glycine max , Fixation de l'azote , Molybdène/pharmacologie , Écosystème , Espèces réactives de l'oxygène/pharmacologie , Engrais , AzoteRÉSUMÉ
Physiological hypoxic conditions in the tumor microenvironment and consequential overexpression of carbonic anhydrase IX (CA IX) are two characteristics shared by numerous types of solid malignant tumors. Early detection with hypoxia assessment is crucial to improve the prognosis and therapy outcomes of hypoxia tumors. Herein, using acetazolamide (AZA) as a CA IX-targeting moiety, we design and synthesize an Mn(II)-based MR imaging probe (named AZA-TA-Mn) incorporating AZA and two Mn(II) chelates of Mn-TyEDTA on a rigid triazine (TA) scaffold. The per Mn relaxivity of AZA-TA-Mn is 2-fold higher than its monomeric Mn-TyEDTA, which allows it for low-dose imaging of hypoxic tumors. In a xenograft mice model of esophageal squamous cell carcinoma (ESCC), a low dosage of AZA-TA-Mn (0.05 mmol/kg) can selectively produce prolonged and stronger contrast enhancement in the tumor compared to the non-specific Gd-DTPA (0.1 mmol/kg). A competition study of co-injection of free AZA and Mn(II) probes confirms the in vivo tumor selectivity of AZA-TA-Mn, resulting in a more than 2.5-fold decreased tumor-to-muscle contrast-to-noise ratio (ΔCNR) at 60 min post-injection. MR imaging results were further supported by the quantitative analysis of Mn tissue levels, as the co-injection of free AZA resulted in significantly reduced Mn accumulation in tumor tissues. Finally, immunofluorescence staining of tissue sections confirms the positive correlation between the tumor accumulation of AZA-TA-Mn and CA IX overexpression. Hence, using CA IX as the hypoxia biomarker, our results illustrate a practical strategy for the development of novel imaging probes for hypoxic tumors.