NO Production Research Articles

Terpenoids from the rhizomes of Curcuma kwangsiensis S.G. Lee et C.F. Ling and their anti-inflammatory activities

Three new sesquiterpenes, 4S-1-(3-hydroxybutyl)-7-(11-hydroxypropyl)-10-methyl- cyclohepta-7,5,10-trien-8-one (1), 8R-hydroxy-7-(4S-4,10-dimethyl-5-oxooct-1-en-7-yl)-11- methylfuran-12-one (2), (1S,5R,7S,10R)-1-hydroxy-7-(11-hydroxypropyl)-10-methyl-4- methyleneoctahydronaphthalen-8-one (3), along with 30 known terpenoids (4–33) were obtained from the rhizomes of Curcuma kwangsiensis S.G. Lee et C.F. Ling. Through comprehensive analysis of chemical evidence and spectral data including UV, ECD, IR, 1D and 2D NMR and HR-ESI-MS, as well as quantum chemical calculation, the structures of these novel compounds were successfully determined. Additionally, the inhibitory effects of compounds 1–2, 4–33 on NO production were evaluated in lipopolysaccharide (LPS)-induced RAW264.7 cells. Notably, compound 33 exhibited the most significant inhibitory effect with an IC50 value of 3.55 ± 0.55 μM.

Sample preservation methods for nitrous oxide concentration and isotope ratio measurements in aquatic environments

AbstractThe nitrogen (N) and oxygen (O) stable isotope analysis of dissolved nitrous oxide (N2O) can provide important constraints on the sources and cycling of N2O in aquatic environments. The isotopic composition of aqueous N2O, both in field (natural abundance) or experimental (15N‐labeling) samples, however, may be altered by abiotic reactions involving nitrite () or hydroxylamine (NH2OH) and microbial activity during sample storage, if samples are not adequately preserved. Here we tested five different preservatives, mercuric chloride (HgCl2), copper sulfate (CuSO4), zinc chloride (ZnCl2), hydrochloric acid (HCl) mixed with sulfamic acid (SFA), and sodium hydroxide (NaOH), for fixing natural water samples from an estuary and a lake with different concentrations over a range of different storage times for N2O analyses. ZnCl2 and CuSO4 decreased the pH, and led to abiotic N2O production from , shifting the N2O isotopic composition significantly. Removal of with a mixture of SFA and HCl did not always prevent the alteration of the original N and O isotope composition of N2O, confirming the requirement for complete removal, and underscoring the biasing effects of at very low pH, even at trace levels. At low background, HgCl2 preservation led to robust and accurate results. However, in light of its toxicity and bioaccumulation potential in food webs, this fixative should be avoided. The addition of NaOH reduced abiotic side reactions involving , and yielded the most reliable and reproducible results for N2O concentration and isotope ratio measurements across tested settings and storage times.

Ab initio MO study on direct production of H2O, N2O and CO3 from the respective CH2OO “Bee-sting-like” attack at H2, N2 and CO2

ContextWe have computationally elucidated the mechanism for formation of H2O, N2O and CO3 from the reactions of CH2OO with H2, N2 and CO2, respectively, by the direct attack of the terminal O atom of CH2OO. This unique mechanism, which is characteristically “bee-sting-like” in nature, was found to be closely parallel to their reactions with the O(1D) atom. Reactions with H2 and CO2 take place by side-on attack, while the N2 reaction occurs by end-on attack with predicted barriers, 19.4, 13.1 and 25.3 kcal.mol−1, respectively. The CO2 reaction with CH2OO was found to occur by producing the C2v CO3, O = C < (O)O, instead of its D3h conformer, essentially similar to the O(1D) + CO2 reaction. The rate constants for the three reactions have been computed by the transition state theory (TST) based on the predicted potential energy profiles. We have also utilized the isodesmic nature of the dative bond exchange in the N2 reaction, CH2O → O + N2 = CH2O + N2 → O, to estimate the heat of the formation of CH2OO. Based on the heat of reaction computed at the highest level of theory employed, we obtained ΔfHo0 (CH2OO) = 27.5 kcal.mol−1; the value agrees with the recent results within ± 1 kcal.mol−1.MethodsAll calculations were performed using Gaussian 16 software. Geometry, frequency, and IRC analysis calculations were conducted at the M06-2X/aug-cc-pVTZ level of theory. The heats of reaction have been evaluated at the highest level, CCSD(T)/CBS(T,Q,5)//M06-2x/aug-cc-pvTz.

Effects and mechanisms of kitchen waste organic fertilizers application on soil nitrogen transformation, plant pathogenic virulence genes, and metabolites

The application of organic fertilizers enhances soil fertility and alters the function and structure of the soil microbial communities. When subjected to aerobic composting, kitchen waste is transformed into organic fertilizer. However, the ecological benefits and safety risks of kitchen waste organic fertilizers (OF) in soil require further evaluation. Therefore, this study conducted a pot experiment to investigate the effects and mechanisms of OF application on soil properties, crop growth, nitrogen transformation, plant pathogenic virulence genes, and metabolites. The results indicated that OF treatment promoted vitamin C synthesis in pakchoi (35.23–48.00 %) and reduced soil N2O emissions during cultivation compared with inorganic fertilizer (IF) (65.50–68.08 %) (P<0.01). IF treatment significantly increased the abundance of Rhodanobacter (6.41 %) and Nitrobacter (3.16 %), leading to increased N2O emissions (17.94 mg kg−1). Key nitrogen metabolism enzymes and functional genes indicated that nitrification and denitrification pathways were the primary contributors to N2O production. Metagenomic results revealed that IF treatment enhanced virulence gene pathogenicity through quorum sensing (QS), whereas OF treatment reduced virulence gene accumulation in plant pathogenic bacteria. Metabolomic analysis demonstrated that OF treatment significantly upregulated substances beneficial to soil activity and plant growth, while inhibiting pollutant expression. PLS-PM results indicated that soil properties played a pivotal role in shaping the intricate relationships among microbial communities, functional genes, and substance metabolism. This study demonstrated that OF application contributed to the promotion of plant health and optimization of soil ecosystems, thereby providing theoretical support for the further expansion of OF applications in agriculture.

Isotopomer labeling and oxygen dependence of hybrid nitrous oxide production

Abstract. Nitrous oxide (N2O) is a potent greenhouse gas and ozone depletion agent, with a significant natural source from marine oxygen-deficient zones (ODZs). Open questions remain, however, about the microbial processes responsible for this N2O production, especially hybrid N2O production when ammonia-oxidizing archaea are present. Using 15N-labeled tracer incubations, we measured the rates of N2O production from ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-) in the eastern tropical North Pacific ODZ and the isotopic labeling of the central (α) and terminal (β) nitrogen (N) atoms of the N2O molecule. We observed production of both doubly and singly labeled N2O from each tracer, with the highest rates of labeled N2O production at the same depths as the near-surface N2O concentration maximum. At most stations and depths, the production of 45N2Oα and 45N2Oβ were statistically indistinguishable, but at a few depths there were significant differences in the labeling of the two nitrogen atoms in the N2O molecule. Implementing the rates of labeled N2O production in a time-dependent numerical model, we found that N2O production from NO3- dominated at most stations and depths, with rates as high as 1600 ± 200 pM N2O d−1. Hybrid N2O production, one of the mechanisms by which ammonia-oxidizing archaea produce N2O, had rates as high as 230 ± 80 pM N2O d−1 that peaked in both the near-surface and deep N2O concentration maxima. Based on the equal production of 45N2Oα and 45N2Oβ in the majority of our experiments, we infer that hybrid N2O production likely has a consistent site preference, despite drawing from two distinct substrate pools. We also found that the rates and yields of hybrid N2O production were enhanced at low dissolved oxygen concentrations ([O2]), with hybrid N2O yields as high as 20 % at depths where [O2] was below detection (880 nM) but nitrification was still active. Finally, we identified a few incubations with [O2] up to 20 µM where N2O production from NO3- was still active. A relatively high O2 tolerance for N2O production via denitrification has implications for the feedbacks between marine deoxygenation and greenhouse gas cycling.

Experimental and numerical study on the influence of N2/H2 on the laminar combustion characteristics of syngas premixed flames

This paper primarily analyzes the influence of N2 and H2 content on the laminar combustion characteristics of low calorific value syngas, using a constant-volume combustion bomb to measure the laminar combustion velocity (SL) of the fuel and compare it with five commonly used mechanisms. The study reveals that higher N2 content significantly reduces the SL of CO/CH4/CO2 mixed fuels, primarily due to a general decrease in the mole fractions of key intermediates and net reaction rates. Increasing H2 content leads to an increase in the SL of CO/CH4/CO2/N2 mixed fuels. The thermal effect becomes increasingly prominent with the elevation of H2 content, while the proportion of thermal effect initially decreases and subsequently increases as the equivalence ratio rises. With the increase in N2 content, the mole fraction of NO experiences a significant decrease, and the rate of decline in thermal NO production is even faster. Conversely, with the increase in H2 content, the rate of rise in non-thermal NO generation is faster, and the mole fraction of NO tends to increase.

Variable contribution of wastewater treatment plant effluents to downstream nitrous oxide concentrations and emissions

Abstract. Nitrous oxide (N2O), a potent greenhouse gas and ozone-destroying agent, is produced during nitrogen transformations in both natural and human-constructed environments. Wastewater treatment plants (WWTPs) produce and emit N2O into the atmosphere during the nitrogen removal process. However, the impact of WWTPs on N2O emissions in downstream aquatic systems remains poorly constrained. By measuring N2O concentrations at a monthly resolution over a year in the Potomac River estuary, a tributary of the Chesapeake Bay in the eastern United States, we found a strong seasonal variation in N2O concentrations and fluxes: N2O concentrations were larger in fall and winter, but the flux was larger in summer and fall. Observations at multiple stations across the Potomac River estuary revealed hotspots of N2O emissions downstream of WWTPs. N2O concentrations were higher at stations downstream of WWTPs compared to other stations (median: 21.2 nM vs. 16.2 nM) despite the similar concentration of dissolved inorganic nitrogen, suggesting the direct discharge of N2O from WWTPs into the aquatic system or a higher N2O production yield in waters influenced by WWTPs. Meta-analysis of N2O measurements associated with WWTPs globally revealed variable influence of WWTPs on downstream N2O concentrations and emissions. Since wastewater production has increased substantially with the growing population and is projected to continue to rise, accurately accounting for N2O emissions downstream of WWTPs is important for constraining and predicting future global N2O emissions. Efficient N2O removal, in addition to dissolved nitrogen removal, should be an essential part of water quality control in WWTPs.

Microscopic insights into the ammonia-methanol blended combustion at high temperatures

Ammonia and methanol have a broad application prospect in the future as green renewable liquid fuels. Methanol has high reactivity and good solubility with ammonia, which is conducive to solving the dilemma of ammonia combustion. However, there are few studies on ammonia-methanol blended combustion, and the effect of blended combustion on the reaction pathways needs to be further investigated. Therefore, this study used the reaction molecular dynamics simulations to reveal the role of methanol on the ammonia combustion and emission process at the microscopic level, focusing on the effects of different fuel blending ratios and oxygen concentration in the air under stoichiometric conditions. The variation of oxidation pathways from ammonia to NO and methanol to CO under different conditions was analyzed in detail. It was found that the methanol accelerated ammonia combustion mainly through enhancing OH production, but methanol and its intermediates inhibited the initial oxidation of ammonia. When the fuel blending ratio was 0.75, the system had lower fuel-type NO production alongside a higher ammonia consumption rate under stoichiometric conditions. The crucial role of NH in the HNO formation at high-temperature ammonia oxidation conditions was revealed. The pathway of HNO + OH → NO + H2O dominated the conversion of HNO to NO in this study. Increasing the methanol content promoted the conversion of NH to HNO and the pyrolysis of HNO while inhibiting the reaction between HNO and O2. In addition, the finding indicated that the high O2 level in air can enhance the reactions between ammonia and OH radicals but inhibit the pyrolysis of CH2OH/CH3O significantly.

Octadecaneuropeptide, ODN, Promotes Cell Survival against 6-OHDA-Induced Oxidative Stress and Apoptosis by Modulating the Expression of miR-34b, miR-29a, and miR-21in Cultured Astrocytes

Astrocytes specifically synthesize and release endozepines, a family of regulatory peptides including octadecaneuropeptide (ODN). We have previously reported that ODN rescues neurons and astrocytes from 6-OHDA-induced oxidative stress and cell death. The purpose of this study was to examine the potential implication of miR-34b, miR-29a, and miR-21 in the protective activity of ODN on 6-OHDA-induced oxidative stress and cell death in cultured rat astrocytes. Flow cytometry analysis showed that 6-OHDA increased the number of early apoptotic and apoptotic dead cells while treatment with the subnanomolar dose of ODN significantly reduced the number of apoptotic cells induced by 6-OHDA. 6-OHDA-treated astrocytes exhibited the over-expression of miR-21 (+118%) associated with a knockdown of miR-34b (−61%) and miR-29a (−49%). Co-treatment of astrocytes with ODN blocked the 6-OHDA-stimulated production of ROS and NO and stimulation of Bax and caspase-3 gene transcription. Concomitantly, ODN down-regulated the expression of miR-34b and miR-29a and rescued the 6-OHDA-associated reduced expression of miR21, indicating that ODN regulates their expression during cell death. Transfection with miR-21-3p inhibitor prevented the effect of 6-OHDA against cell death. In conclusion, our study indicated that (i) the expression of miRNAs miR-34b, miR-29a, and miR-21 is modified in astrocytes under 6-OHDA injury and (ii) that ODN prevents this deregulation to induce its neuroprotective action. The present study identified miR-21 as an emerging candidate and as a promising pharmacological target that opens new neuroprotective therapeutic strategies in neurodegenerative diseases, especially in Parkinson’s disease.

Effects of aeration control strategies on nitrous oxide emissions in alternating anoxic–oxic sequencing batch reactor systems

Reducing N2O emissions is key to controlling greenhouse gases (GHG) in wastewater treatment plants (WWTPs). Although studies have examined the effects of dissolved oxygen (DO) on N2O emissions during nitrogen removal, the precise effects of aeration rate remain unclear. This study aimed to fill this research gap by investigating the influence of dynamic aeration rates on N2O emissions in an alternating anoxic–oxic sequencing batch reactor system. The emergence of DO breakthrough points indicated that the conversion of ammonia nitrogen to nitrite and the release of N2O were nearly complete. Approximately 91.73±3.35% of N2O was released between the start of aeration and the DO breakthrough point. Compared to a fixed aeration rate, dynamically adjusting the aeration rates could reduce N2O production by up to 48.6%. Structural equation modelling revealed that aeration rate and total nitrogen directly or indirectly had significant effects on the N2O production. A novel regression model was developed to estimate N2O production based on energy consumption (aeration flux), water quality (total nitrogen), and GHG emissions (N2O). This study emphasizes the potential of optimizing aeration strategies in WWTPs to significantly reduce GHG and improve environmental sustainability.

Neuroprotective effects of fermented blueberry and black rice against particulate matter 2.5 μm-induced inflammation in vitro and in vivo

The increasing prevalence of particulate matter (PM) has raised significant concerns about its adverse effects on human health. This study investigates the potential of fermented blueberry and black rice (FBBR) in mitigating the effects of PM2.5 in SH-SY5Y cells and mice. Various assays, including MTT, NO, western blot, ELISA, and behavioral studies were conducted. Results showed that PM2.5 induced considerable cytotoxicity and elevated NO production at a concentration of 100 μg/mL of PM2.5 in SH-SY5Y cells. FBBR administration attenuated PM2.5-exposed cytotoxicity and suppressed NO production in SH-SY5Y cells. In an intranasally-exposed mice model, 10 mg/kg body weight (BW) of PM2.5 resulted in cognitive impairments. However, FBBR treatment ameliorated these impairments in both the Y-maze and MWM tests in PM2.5-exposed mice. Additionally, FBBR administration increased the expression of BDNF and reduced inflammatory markers in the brains of PM2.5-exposed SH-SY5Y cells. These findings highlight the detrimental effects of PM2.5 on the nervous system and suggest the potential of FBBR as a nutraceutical agent for mitigating these effects. Importantly, the results emphasize the urgency of addressing the harmful impact of PM2.5 on the nervous system and underscore the promising role of FBBR as a protective intervention against the adverse effects associated with PM2.5 exposure.

A novel anti-inflammatory flavonoid from flowers of Hibiscus mutabilis L

Hibiscus mutabilis L. is a Traditional Chinese Medicinal plant of significant value. However, there has been limited research focusing specifically on its flowers. In this study, we report the isolation of one novel and nine known flavonoids from the flowers of H. mutabilis L. The structures of these compounds were elucidated using chemical and comprehensive spectral analysis, involving 1D, 2D NMR, and HRESIMS. The novel compound was further evaluated for its anti-inflammatory and cytotoxic activities using in vitro assays on RAW264.7 cells. Compound 1 at the concentration of 6.25 μM significantly inhibited the production of NO and TNF-α induced by LPS in RAW264.7 cells, exhibiting superior efficacy compared to the positive control dexamethasone, thus indicating its potential as an anti-inflammatory drug candidate.

Water residence time controls seasonal nitrous oxide budget in a semi-enclosed bay: Insights from an improvement estimation method

This study developed an estimation method for the N2O budget using 15N stable isotope labeling techniques, a dual-layer model and a box model, which was used to elucidate the underlying dynamics of N2O accumulation in Zhanjiang Bay. The results showed that although the net input of N2O during the rainy season was 2.36 times higher than that during the dry season, the overall N2O concentration was only 66.6 % of that during the dry season due to the extended water residence time in the dry season. Our findings highlighted that water residence time was the key factor for the N2O emission, and a longer water residence time was unfavorable for the efflux of N2O through hydrodynamic processes and was more conducive to the production and accumulation of N2O within the bay. This research enhanced our comprehension of N2O dynamics and provided crucial insights for refining nitrogen management strategies and mitigation efforts.

NO Formation in Combustion Engines Fuelled by Mixtures of Hydrogen and Methane

The present work addresses the production of nitrogen oxides in ICEs burning hydrogen mixed with methane. A mathematical model that allows the calculation of nitrogen oxide emissions from such combustion was built; this model uses the extended chemical kinetic mechanism of Zeldovich. Numerical simulations were carried out on the production of NO, varying the following variables: proportion of H2 to CH4, the equivalence ratio of the reactant mixture, the compression ratio, and the engine speed. The essential purpose was to assess how NO production is affected by the mentioned variables. The main assumptions were (i) Otto cycle; (ii) instantaneous combustion; (iii) chemical equilibrium reached just at the end of combustion; (iv) the formation of NO only during the expansion stroke of pistons. Results were obtained for various proportions of hydrogen and methane, various equivalence ratios, speeds of rotation, and compression ratios of an engine. In short, the results obtained in the current work show that the lowering of the equivalence ratio leads to a lower concentration of NO; that increasing the compression ratio also lowers the concentration of NO; that NO production occurs until shortly after the beginning of the expansion stroke; and finally, that the NO concentration in the engine exhaust is not very sensitive to the H2/CH4 ratio in the fuel mixture.

NO Formation in Combustion Engines Fuelled by Mixtures of Hydrogen and Methane

The present work addresses the production of nitrogen oxides in ICEs burning hydrogen mixed with methane. A mathematical model that allows the calculation of nitrogen oxide emissions from such combustion was built; this model uses the extended chemical kinetic mechanism of Zeldovich. Numerical simulations were carried out on the production of NO, varying the following variables: proportion of H2 to CH4, the equivalence ratio of the reactant mixture, the compression ratio, and the engine speed. The essential purpose was to assess how NO production is affected by the mentioned variables. The main assumptions were (i) Otto cycle; (ii) instantaneous combustion; (iii) chemical equilibrium reached just at the end of combustion; (iv) the formation of NO only during the expansion stroke of pistons. Results were obtained for various proportions of hydrogen and methane, various equivalence ratios, speeds of rotation, and compression ratios of an engine. In short, the results obtained in the current work show that the lowering of the equivalence ratio leads to a lower concentration of NO; that increasing the compression ratio also lowers the concentration of NO; that NO production occurs until shortly after the beginning of the expansion stroke; and finally, that the NO concentration in the engine exhaust is not very sensitive to the H2/CH4 ratio in the fuel mixture.

Three-stage hybrid NSD/DC plasma assisted n-C5H12/O2/N2 ignition: Improved energy efficiency and reduced NOx/N2O emissions

This work presents a three-stage hybrid nanosecond discharge (NSD) and direct current (DC) discharge assisted n-C5H12/O2/N2 ignition with lower discharge energy and higher energy efficiency. The reaction rate coefficients between O2(a1Δg) and n-C5H12 are updated by mass/Master equation simulation. The promotive ignition enhancement via reaction channel O2(a1Δg) + n-C5H12 → C5H10 + H2O2 in the hybrid NSD/DC discharge is demonstrated. The results show that the ignition delay time of the three-stage hybrid plasma assisted ignition is 1–2 orders of magnitude shorter than that of the two-stage hybrid discharge when the reduced electric field strength in the DC discharge stage is over 10 Td. Meanwhile, the plasma-enhanced energy efficiency of three-stage hybrid discharge increases. This improved efficiency on ignition enhancement is due to the kinetic enhancement by the electronically excited species and radicals (O2(a1Δg), O(1D), N2(B) and O). The kinetic and thermal effects by plasma are effectively intergated to enhance ignition. However, more discharge energy deposited in the vibrationally excited states N2(v) in the two-stage hybrid discharge is less efficient on ignition enhancement due to the thermal contribution via vibrational-translational relaxation. In the aspect of NOx/N2O emissions, reduction efficiency of the three-stage hybrid discharge is two times higher than that of the two-stage hybrid discharge. By controlling the N/N(2D) production pathway e + N2 → e + N + N(2D), the three-stage hybrid discharge reduces NOx and N2O production by 61.1 % and 90 %, respectively. The results show that the ignition delay time is non-monotonically dependent on the discharge pulse number. There exist optimal pulse number, reduced electric field and effective threshold power density of DC discharge to achieve maximum ignition enhancement and low NOx/N2O emissions. This study provides valuable insights into the use of NSD/DC hybrid discharge technology in advanced engines to achieve energy-efficient ignition enhancement and reduce NOx/N2O emissions.

Investigation On A Novel Injector Concept For Spinning Combustion Technology In High-Pressure Conditions By Advanced Laser-Based Diagnostics

Safran Helicopter Engines has recently patented the spinning combustion technology in which the burnt gases from one injector travel tangentially along the combustor annulus towards the neighboring injectors. Compared to conventional designs, the new kerosene injection systems are dedicated to improve air/fuel mixture ignition but also to further reduce NOx and soot particle emissions. Experimental studies are performed on these fuel injectors in a high-pressure/high-temperature combustion facility designed by the CORIA research laboratory. This test bench is able to reproduce the same operating conditions encountered in a helicopter combustor over the entire range of nominal operating conditions and has large optical accesses for the implementation of laser-based diagnostics. In the current paper, we present results concerning flame structure and NO formation in the primary zone under pressure conditions of up to 14 bar, using simultaneous OH-PLIF, NO-PLIF and kerosene-PLIF laser diagnostics. These experimental studies were supplemented by high-speed PIV measurements. A good spatial correlation between the distribution of liquid and vapour kerosene and the location of the flame front was observed. Depending on the operating conditions in terms of fuel/air ratio, mass flow rates and pressure, different flame structures resulting from the modification of the interaction between fuel injection and aerodynamics are observed. Furthermore, it was found that the Zeldovich pathway mainly controls the formation of NO in the vicinity of the flame front. In addition, the effects of FAR and pressure also have a significant impact on NO production. All these results are now intended to serve as a comprehensive validation database for the development and testing of high-fidelity LES tools dedicated to the simulation of reactive flows in aero-engine combustion chambers.

Inhibitory Effects of Biochar on N2O Emissions through Soil Denitrification in Huanghuaihai Plain of China and Estimation of Influence Time

Biochar application is considered an effective method for reducing nitrous oxide (N2O) emissions from soil. However, the mechanisms underlying the influence of various biochar dosages on soil N2O emissions and the duration of one-time biochar application remain unclear. The effects of different biochar application rates and a one-time application on soil N2O emissions in the Huanghuaihai Plain of China were investigated through a field experiment from 2020 to 2022. In the wheat and maize rotation system, six treatments were administered: no biochar (C0); 2 (C1), 4 (C2), 8 (C3), and 12 t/hm2 biochar (C4) applied annually; and a one-time application of 12 t/hm2 biochar (CS) in 2018. Our results indicate that, compared with C0, biochar significantly inhibited soil N2O emissions, particularly in the C3 and C4 treatments, with reductions of 31.36–56.21% and 36.92–52.45%, respectively. However, CS did not significantly affect soil N2O emissions during the study period. These findings suggest that the biochar’s inhibitory effect on soil N2O emissions is contingent upon the dosage and frequency of application. A structural equation model revealed that biochar decreases soil N2O emissions by enhancing the reduction in N2O during denitrification. Under the conditions of this experiment, based on a logistic ecological model, a one-time application of 12 t/hm2 biochar was projected to significantly reduce soil N2O emissions for approximately 1.77 years. On the whole, biochar reduces soil N2O emissions mainly by regulating N2O production through denitrification, and the duration of this inhibition of N2O emissions mainly depends on the application amount and frequency of biochar application.

Inhibitory Effects of Biochar on N2O Emissions through Soil Denitrification in Huanghuaihai Plain of China and Estimation of Influence Time

Biochar application is considered an effective method for reducing nitrous oxide (N2O) emissions from soil. However, the mechanisms underlying the influence of various biochar dosages on soil N2O emissions and the duration of one-time biochar application remain unclear. The effects of different biochar application rates and a one-time application on soil N2O emissions in the Huanghuaihai Plain of China were investigated through a field experiment from 2020 to 2022. In the wheat and maize rotation system, six treatments were administered: no biochar (C0); 2 (C1), 4 (C2), 8 (C3), and 12 t/hm2 biochar (C4) applied annually; and a one-time application of 12 t/hm2 biochar (CS) in 2018. Our results indicate that, compared with C0, biochar significantly inhibited soil N2O emissions, particularly in the C3 and C4 treatments, with reductions of 31.36–56.21% and 36.92–52.45%, respectively. However, CS did not significantly affect soil N2O emissions during the study period. These findings suggest that the biochar’s inhibitory effect on soil N2O emissions is contingent upon the dosage and frequency of application. A structural equation model revealed that biochar decreases soil N2O emissions by enhancing the reduction in N2O during denitrification. Under the conditions of this experiment, based on a logistic ecological model, a one-time application of 12 t/hm2 biochar was projected to significantly reduce soil N2O emissions for approximately 1.77 years. On the whole, biochar reduces soil N2O emissions mainly by regulating N2O production through denitrification, and the duration of this inhibition of N2O emissions mainly depends on the application amount and frequency of biochar application.

Vitifolignans, 3,4-dibenzyltetrahydrofuran lignans from Anemone vitifolia Buch.-Ham.

Anemone vitifolia is a small herb found in Asia that is used to treat a range of diseases in Chinese traditional medicine. GNPS-based molecular networking of an Anemone vitifolia specimen revealed the presence of a network containing numerous ions indicating the presence of lignans, several of which suggested that there might be previously undescribed compounds in the extract. Fractionation of the organic extract yielded five undescribed lignans, the vitifolignans, together with one known. The structures were identified based on extensive spectroscopic data analysis (NMR, HR-ESI-MS, and UV), coupling constant calculation and comparison with reported data. Their absolute configurations were determined by comparison of experimental ECD spectra with calculated spectra. Compounds 4/5 showed weak inhibition of LPS-induced NO production in mouse mononuclear macrophages.