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Abstract U.S. rice paddies, critical for food security, are increasingly contributing to non‐CO2 greenhouse gas (GHG) emissions like methane (CH4) and nitrous oxide (N2O). Yet, the full assessment of GHG balance, considering trade‐offs between soil organic carbon (SOC) change and non‐CO2 GHG emissions, is lacking. Integrating an improved agroecosystem model with a meta‐analysis of multiple field studies, we found that U.S. rice paddies were the rapidly growing net GHG emission sources, increased 138% from 3.7 ± 1.2 Tg CO2eq yr−1 in the 1960s to 8.9 ± 2.7 Tg CO2eq yr−1 in the 2010s. CH4, as the primary contributor, accounted for 10.1 ± 2.3 Tg CO2eq yr−1 in the 2010s, alongside a notable rise in N2O emissions by 0.21 ± 0.03 Tg CO2eq yr−1. SOC change could offset 14.0% (1.45 ± 0.46 Tg CO2eq yr−1) of the climate‐warming effects of soil non‐CO2 GHG emissions in the 2010s. This escalation in net GHG emissions is linked to intensified land use, increased atmospheric CO2, higher synthetic nitrogen fertilizer and manure application, and climate change. However, no/reduced tillage and non‐continuous irrigation could reduce net soil GHG emissions by approximately 10% and non‐CO2 GHG emissions by about 39%, respectively. Despite the rise in net GHG emissions, the cost of achieving higher rice yields has decreased over time, with an average of 0.84 ± 0.18 kg CO2eq ha−1 emitted per kilogram of rice produced in the 2010s. The study suggests the potential for significant GHG emission reductions to achieve climate‐friendly rice production in the U.S. through optimizing the ratio of synthetic N to manure fertilizer, reducing tillage, and implementing intermittent irrigation.

Abstract Inland waters are significant, yet highly uncertain, natural sources of nitrous oxide (N2O). Many emission models assume that N2O is only emitted from freshwaters, and that N2O sink behavior is negligible. However, observational studies have reported N2O undersaturation, suggesting that inland waters can act as N2O sinks due to net N2O consumption. This study leverages data from the National Ecological Observatory Network (NEON) and an existing global emission model to examine the prevalence of and controls on N2O undersaturation in streams, rivers, and lakes across scales and biomes. We find that N2O undersaturation is prevalent in the NEON data set (14%–30% of samples) and process‐based model outputs (38%), occurring across biomes and spatial scales. Failing to account for undersaturation in the NEON data set could result in an 100% overestimation of N2O emissions. These results show that consideration of N2O sink behavior is needed for accurate emission estimates.

Abstract Monoculture croplands are a major source of global anthropogenic emissions of nitrous oxide (N2O), a potent greenhouse gas that contributes to ozone depletion. Agroforestry has the potential to reduce N2O emissions. Presently, there is no systematic comparison of soil N2O emissions between cropland agroforestry and monoculture systems in Central Europe. We investigated the effects of converting the monoculture cropland system into the alley cropping agroforestry system on soil N2O fluxes at three sites (each site has paired agroforestry and monoculture) in Germany, where agroforestry combined crop rows and poplar short‐rotation coppice (SRC). We measured soil N2O fluxes monthly over 2 years (March 2018–January 2020) using static vented chambers. Annual soil N2O emissions from agroforestry ranged from 0.21 to 2.73 kg N ha−1 year−1, whereas monoculture N2O emissions ranged from 0.34 to 3.00 kg N ha−1 year−1. During the rotation of corn crop, with high fertilization rates, agroforestry reduced soil N2O emissions by 9% to 56% compared to monocultures. This was mainly caused by low soil N2O emissions from the unfertilized agroforestry tree rows. Soil N2O fluxes were predominantly controlled by soil mineral N in both agroforestry and monoculture systems. Our findings suggest that optimized fertilizer input will further enhance the potential of agroforestry for mitigating N2O emissions.

Abstract Inland waters play a major role in global greenhouse gas (GHG) budgets. The smallest of these systems (i.e., ponds) have a particularly large—but poorly constrained—emissions footprint at the global scale. Much of this uncertainty is due to a poor understanding of temporal variability in emissions. Here, we conducted high‐resolution temporal sampling to quantify GHG exchange between four temperate constructed ponds and the atmosphere on an annual basis. We show these ponds are a net source of GHGs to the atmosphere (564.4 g CO2‐eq m−2 yr−1), driven by highly temporally variable diffusive methane (CH4) emissions. Diffusive CH4 release to the atmosphere was twice as high during periods when the ponds had a stratified water column than when it was mixed. Ebullitive CH4 release was also higher during stratification. Building ponds to favor mixed conditions thus presents an opportunity to minimize the global GHG footprint of future pond construction.

Key Clinical Message Frostbite arising from nitrous oxide (N2O) inhalation is rare. As such, there is no consensus on best treatment for these injuries. In all published reports, judicious use of corticosteroids and antibiotics has resulted in positive clinical outcomes; we endorse these agents in our case of a young man with oropharyngeal burns.

Abstract The recreational use of nitrous oxide (N2O) is sharply increasing among young adults. N2O abuse can cause serious complications. However, the association between acute pancreatitis and N2O is rarely reported. Here we report a case of a young and previously healthy female with widespread cutaneous lesions, neurologic symptoms, and abdominal pain. Acute pancreatitis was the patient's primary diagnosis when she was admitted to the gastroenterology unit. We added the diagnosis of N2O intoxication after an additional inquiry into the patient's personal history revealed that she had abused N2O for 1 month. With the application of mecobalamin and other symptomatic treatments, the symptoms and laboratory indexes improved gradually. In this case, we highlight that acute pancreatitis may be a rare complication induced by N2O.

Abstract Introduction Nitrification inhibitors and straw incorporation are used to reduce microbial mediated nitrogen (N) losses, thereby increasing N use efficiency (NUE) in cropland soil, but their effects on nitrous oxide (N2O) emission across different soil types and the underlying molecular mechanisms remain less understood. Materials and Methods In this study, we investigated how nitrification inhibitor nitrapyrin and straw incorporation affected soil N balance, N2O emission, nitrifiers and denitrifiers in three cropland soils (black, fluvo‐aquic and red soils). Results Compared with fertilization‐only treatment (N), nitrapyrin addition increased ammonium, while it decreased nitrate concentration in all soils; however, the performance of straw incorporation was less significant. Nitrapyrin decreased N2O emission only in the fluvo‐aquic soil, while straw incorporation strongly increased N2O emission in the red soil. Terminal restriction fragment length polymorphism analysis revealed that the denitrifier community was distinct across the three soils, but not strongly structured by nitrapyrin or straw incorporation. Compared with the N treatment, straw incorporation and nitrapyrin increased nosZ gene abundance only in the black soil. Structural equational modelling further confirmed that, after accounting for different soil properties, straw incorporation significantly increased N2O emission from black and red soils, and a decrease in nosZ gene abundance was the main biological factor for increased N2O emission in red soil. Conclusion Taken together, our work provides new knowledge that the performance of nitrification inhibitor and straw incorporation on N2O emission is soil type‐dependent, and management practices should be used as per soil type to balance NUE and N2O emission.

Abstract Nitrous oxide abuse can have detrimental effects on the central and peripheral nervous systems. This case study report aims to demonstrate a combination of severe generalized sensorimotor polyneuropathy and cervical myelopathy related to vitamin B12 deficiency following nitrous oxide abuse. We present a clinical case study and literature review examining primary research—published between 2012 and 2022—reporting nitrous oxide abuse affecting the spinal cord (myelopathy) and peripheral nerves (polyneuropathy); 35 articles were included in the review with a total of 96 patients, where the mean “patients” age was 23.9 years and were in a 2:1 male/female ratio. Of the 96 cases, within the review, 56% of patients were diagnosed with polyneuropathy, most commonly impacting the nerves of the lower limb (62%), while 70% of patients were diagnosed with myelopathy, most commonly impacting the cervical region (78%) on the spinal cord. In our clinical case study, a 28‐year‐old male underwent a multitude of diagnostic investigations for bilateral “foot drop” and sense of lower limb stiffness as ongoing complications of a vitamin B12 deficiency secondary to recreational nitrous oxide abuse. Both the literature review and our case report emphasize the dangers of recreational nitrous oxide inhalation, colloquially termed “nanging” and the risks it presents to both the central and peripheral nervous systems, which is erroneously considered by many recreational drug users to be less harmful than other illicit substances.

Abstract Legume cover crops are central to an ecological nutrient management approach that can reduce nitrogen (N) losses from agriculture. Diversifying cropping systems with a legume–grass cover crop mixture could further reduce N losses by increasing soil N assimilation and synchronizing N mineralization with N uptake by the following crop. We established four winter cover crop treatments (crimson clover, cereal rye, clover–rye mixture, and weedy fallow control) in an organic grain agroecosystem that had been managed for 30 years with a legume cover crop as the only external N source. We hypothesized that the legume–grass mixture would provide similar inputs of biologically fixed N2 compared with the sole legume, while reducing N2O emissions during decomposition following tillage. We measured cover crop aboveground biomass C:N and clover N2 fixation, soil inorganic N and N2O fluxes throughout the corn growing season following cover crop tillage, and corn N assimilation at harvest. Even with a reduced clover seeding rate in mixture, the clover and mixture treatments had similar fixed N inputs, litter N and C:N, and no differences in cumulative N2O emissions. During the first peak flux, N2O emissions were 2–5 times higher in clover and mixture relative to rye and fallow, with no differences between clover and mixture. There were no treatment differences at the second N2O peak, which followed the first major rain event. We contextualized these findings by calculating a 6‐year partial N mass balance for this agroecosystem, which was slightly negative (−6.8 ± 0.8 kg N ha−1 year−1) when accounting for historical mean annual N2O emissions and nitrate leaching. Overall, N inputs and harvested N exports were approximately in balance for this legume‐based crop rotation, suggesting that the legacy of ecological nutrient management has promoted efficient N cycling. However, results from our field experiment indicate that short‐term N2O flux rates following cover crop incorporation can be high even for a legume–grass mixture. Additional strategies to reduce soil disturbance are therefore needed to further tighten N cycling in organic grain agroecosystems.

Abstract Nitrous oxide is a gas frequently used in the medical/dental field for anesthesia and analgesic purposes and in the food industry as a spray propellant or foaming agent. Overexposure can lead to subacute combined degeneration (SACD) of the spinal cord through the mechanism of vitamin B12 deficiency. Because this drug is easily accessible, relatively inexpensive, and legal to possess, it has potential to be abused for recreational purposes. The number of published cases of nitrous oxide abuse has been increasing since 2010. Large‐scale and long‐term use of nitrous oxide have been found to cause nerve damage from vitamin B12 deficiency, thromboembolic phenomenon from elevated homocysteine levels, and even death from hypoxia. A 44‐year‐old male patient with past medical history of recently diagnosed type 2 diabetes, on Metformin, presented for 1 month of worsening bilateral upper and lower extremity weakness. On initial physical examination, he demonstrated pertinent abnormal findings of 2/5 hand strength bilaterally, 4/5 strength in his left upper extremity and right lower extremity, impaired coordination, ataxic gait, rigidity, and decreased but symmetrical reflexes. He reported using 50–100 canisters of nitrous oxide per day to obtain a feeling of relaxation and euphoria. Blood work revealed vitamin B12 deficiency, and abnormalities were seen on MRI. He was treated with 1000 μg of intramuscular vitamin B12 every other day for 3 doses, followed by 500 μg oral cyanocobalamin daily. He demonstrated a great amount of improvement in his neuropathy during his stay. However, he was still dependent in basic transfers, activities of daily living, and mobility and was discharged to acute rehabilitation. Vitamin B12 deficiency can lead to subacute combined degeneration, which presents with sensory deficits, weakness, ataxia, spasticity, and gait abnormalities. Treatment for SACD should be aggressive and rapid to prevent irreversible neurological deficits. Amid an opioid epidemic, practitioners can easily overlook the use of nitrous oxide and patients may consider this drug to be relatively harmless. This case demonstrates the importance of thorough history taking, patient education, and early recognition and treatment of vitamin B12 deficiency and the deleterious effects that may result without intervention.

Background: The factors underlying the topography of nitrous oxide (N 2 O)-induced neurological complications are unknown., Methods: We included all consecutive patients admitted to the university hospital of Marseille for N 2 O-induced neurological complications in a prospective observational study. Patients underwent neurological examination, spinal cord magnetic resonance imaging, and nerve conduction studies within the first 4 weeks after admission., Results: In total, 61 patients were included: 45% with myeloneuropathy, 34% with isolated myelopathy, and 21% with isolated neuropathy. On multivariable analysis, the odds of myelopathy were associated with the amount of weekly N 2 O consumption (~600 g cylinder per week, odds ratio [OR] = 1.11, 95% confidence interval [CI] = 1.001-1.24). The extent of the myelopathy (number of vertebral segments) was correlated with the number of ~600-g cylinders consumed weekly (ρ = 0.40, p < 0.005). The odds of neuropathy were associated with the duration of consumption (per month; OR = 1.29, 95% CI = 1.05-1.58). Mean lower-limb motor nerve amplitude was correlated with the duration of consumption (in months; ρ = -0.34, p < 0.05)., Conclusions: The odds of myelopathy increased with the amount of N 2 O consumption, and the odds of neuropathy increased with the duration of N 2 O exposure, which suggests distinct pathophysiological mechanisms underlying these two neurological complications., (© 2024 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Abstract Background During thoracoscopic segmentectomy, accurately and rapidly identifying the intersegmental plane (ISP) is of great importance. This study aimed to investigate the effect and safety of a nitrous oxide (N2O)/oxygen (O2) inspired mixture on the appearance time of the ISP (TISP) via the modified inflation‐deflation method. Methods A total of 65 participants who underwent segmentectomy were randomized into three groups: 75% N2O (n = 24), 50% N2O (n = 23) or 0% N2O (n = 18). The 75% N2O group received a gas mixture of N2O/O2 (Fio2 = 0.25), the 50% N2O group received N2O/O2 (Fio2 = 0.5), and the 0% N2O group received 100% oxygen during lung expansion. The appearance time of satisfactory and ideal planes was recorded. Furthermore, arterial blood gas at breathing room air, one‐lung ventilation (OLV) before lung expansion, 5 and 15 min after lung expansion were also recorded. Results TISP was significantly shorter in the 75% N2O group (320.2 ± 65.9 s) compared with that of the 50% N2O group (552.4 ± 88.9 s, p

Abstract Purpose To review the clinical symptoms, auxiliary examination findings, and outcomes of patients with nitrous oxide (N2O) abuse, and analyze the factors that affect outcomes. Methods Patients with N2O abuse treated in the Department of Neurology between January 2018 and December 2020 were included. The clinical data of these patients were collected, and follow‐up was conducted to determine the outcomes. Results The average age of the 110 patients with N2O abuse was 21.4 ± 4.2 years (range: 14–33 years). Clinical presentation primarily included neurological symptoms, such as limb numbness and/or weakness (97%), psychiatric symptoms, changes in appetite, and skin hyperpigmentation. Laboratory test results were characterized by vitamin B12 deficiency (60%, 34 out of 57 cases) and high homocysteine level (69%, 31 out of 45 cases). Electromyography indicated mixed axonal and demyelination injury (92%, 80 out of 87 cases). Motor and sensory nerves were simultaneously involved, and injury primarily involved the lower limbs. One hundred and seven (97%) patients were clinically diagnosed with peripheral neuropathy, of whom 26 (24%) exhibited spinal abnormalities on magnetic resonance imaging, supporting a diagnosis of subacute combined degeneration. Treatment included N2O withdrawal and vitamin B12 supplementation. Reexamination of six patients indicated that treatment was effective. Follow‐up was completed for 51 patients. Thirty‐four patients (67%) recovered completely, 17 patients (33%) had residual limb numbness, and only one patient experienced relapse. Sex was an independent prognostic factor; the outcomes of female patients were better than that of male patients. Conclusion The recreational use of N2O has largely expanded among youth in recent decades, which has become a growing public health concern in China. It highlights the importance of the recognition of various clinical symptoms, particularly limb numbness and/or weakness related to the cases of N2O abuse. The therapeutic administration of vitamin B12 supplementation and N2O withdrawal can make the overall prognosis good, especially for female patients.

Abstract The application of organic materials to soil can recycle nutrients and increase organic matter in agricultural lands. Digestate can be used as a nutrient source for crop production but it has also been shown to stimulate greenhouse gas (GHG) emissions from amended soils. While edaphic factors, such as soil texture and pH, have been shown to be strong determinants of soil GHG fluxes, the impact of the legacy of previous management practices is less well understood. Here we aim to investigate the impact of such legacy effects and to contrast them against soil properties to identify the key determinants of soil GHG fluxes following digestate application. Soil from an already established field experiment was used to set up a pot experiment, to evaluate N2O, CH4 and CO2 fluxes from cattle‐slurry‐digestate amended soils. The soil had been treated with farmyard manure, green manure or synthetic N‐fertilizer, 18 months before the pot experiment was set up. Following homogenization and a preincubation stage, digestate was added at a concentration of 250 kg total N/ha eq. Soil GHG fluxes were then sampled over a 64 day period. The digestate stimulated emissions of the three GHGs compared to controls. The legacy of previous soil management was found to be a key determinant of CO2 and N2O flux while edaphic variables did not have a significant effect across the range of variables included in this experiment. Conversely, edaphic variables, in particular texture, were the main determinant of CH4 flux from soil following digestate application. Results demonstrate that edaphic factors and current soil management regime alone are not effective predictors of soil GHG flux response following digestate application. Knowledge of the site management in terms of organic amendments is required to make robust predictions of the likely soil GHG flux response following digestate application to soil.

Abstract Enhanced ultraviolet‐B (UV‐B) radiation is induced by the depletion of the stratospheric ozone layer. Silicate is beneficial to rice growth and can increase the resistance of rice plant to UV‐B radiation, but so far few reports have been available on whether silicate application can reduce CH4 and N2O emissions from paddy soils under enhanced UV‐B radiation. A field experiment was conducted to investigate the effects of silicate application on CH4 and N2O emissions and global warming potentials (GWPs) under enhanced UV‐B radiation in a paddy soil. The experiment with rice was designed with two UV‐B radiation levels, that is, ambient UV‐B (A, ambient) and enhanced UV‐B radiation (E, enhanced by 20%); and two silicate application levels, that is, control (Si0, 0 kg SiO2·ha−1) and silicate application (Si1, 200 kg SiO2·ha−1). CH4 and N2O fluxes were determined by closed chamber method at one‐week interval during rice growth period. The results show that, compared with ambient UV‐B radiation, enhanced UV‐B radiation clearly decreased the dry matter weights of shoot, root, and whole plant by 13.12%, 53.31%, and 25.85%, respectively, in the treatment without silicate application, and by 1.47%, 34.49%, and 11.12%, respectively, in the treatment with silicate application. Enhanced UV‐B radiation significantly increased the flux and cumulative emission of N2O and stimulated the GWPs of CH4 and N2O. Silicate application significantly reduced flux and cumulative emission of CH4, promoted the flux and cumulative emission of N2O, and reduced the GWPs of CH4 and N2O. This study suggests that silicate application can reduce the contribution of enhanced UV‐B radiation to global warming potentials.

Abstract Background Recreational N2O abuse is an important etiology of neurological impairment in young patients, which may easily be ignored clinically. Few current studies have investigated the characteristics or the effects experienced by its users. We aimed to explore any correlation between the clinical severity and biomarkers and spinal magnetic resonance imaging (MRI) abnormalities, identify independent factors associated with spinal MRI abnormalities, and ascertain factors affecting depression/anxiety in patients with N2O‐related neurological disorders. Methods Patients with N2O‐related neurological disorders were enrolled retrospectively between February 2017 and July 2020. Their demographic, clinical, laboratory, neuroimaging, electrophysiological, and neuropsychological findings were analyzed. Correlation analyses were conducted using Spearman's or Pearson's correlation and linear regression analysis. Independent factors associated with spinal MRI abnormalities were identified using univariate and multivariate analyses. Results The principal clinical manifestations of N2O‐related neurological disorders (n = 63; 38 men, 25 women; mean age ± SD: 22.60 ± 4.46 years) were sensory disturbance, followed by gait disturbance and pyramidal tract damage. A significant negative correlation existed between serum vitamin B12 levels and clinical severity (r = −0.309, p = .014), which disappeared after linear regression. An interval of less than 6 months between initial N2O abuse and hospitalization was independently associated with spinal MRI abnormalities (39.47% vs. 72.00%, respectively; χ2 = 6.40, p = .01). Thirty‐eight (60.32%) and 40 (63.49%) patients experienced anxiety and depression, respectively. Moreover, the higher the clinical scores/serum homocysteine levels, the greater the severity of anxiety/depression (r = 0.442, p

Abstract Purpose This study investigated the clinical epidemiological characteristics of nitrous oxide (N2O) abusers in a hospital in China, which have not been systematically reported. Methods The characteristics of patients abusing N2O who were examined and treated at the Affiliated Hospital of Xuzhou Medical University from January 2017 to December 2020 were analyzed. Results A total of 61 patients (average age: 21.7 ± 3.2 years; 42 male and 19 female) were enrolled; 60.7% of the patients had an education level of high school or lower, and most (59.0%) had no stable occupation. The mean exposure time was 8.5 ± 7.7 months (range: 1–36 months). Only 52.5% of the abusers reported the physician of the relevant exposure history at the first time of visiting the doctor. The main clinical type was mixed (49.2%). The most common clinical manifestation was distal limb numbness (80.3%). The most frequent outcome was peripheral neuropathy (59%) and subacute combined degeneration (36%). Serum homocysteine level was elevated in 67.5% (27/40) of the patients, while 44.4% (20/45) showed reduced vitamin B12. Note that 61% (22/36) showed abnormal signals in the posterior or lateral funiculus of the spinal cord, and 97% (31/32) of the patients showed peripheral nerve damage by electromyography. In all cases, symptoms were alleviated after halting N2O intake and receiving nutritional neurotherapy. Conclusions N2O abuse can lead to nervous system damage, especially peripheral nerve and spinal cord damage. A full understanding of its clinical epidemiological characteristics is helpful for clinicians to make a timely and clear diagnosis.

Background and Aim: Recreational use of nitrous oxide (N 2 O) has been associated with the development of severe nitrous oxide-induced neuropathy (N 2 On). Follow-up of these patients poses challenges, and their clinical progression remains largely unknown. The identification of prognostic factors is made difficult by the lack of standardized longitudinal assessments in most studies. The objective was to document the course of neuropathy through systematic follow-up assessments in N 2 On patients to identify prognostic factors for persistent disability after 6 months., Methods: We gathered demographic, clinical, biological, and electrophysiological data from N 2 On patients hospitalized in the Referral center in Marseille, both at baseline and during a standardized follow-up assessment at 6 months., Results: We retrospectively included 26 N 2 On patients (mean age 22.6 ± 4.4). Significant improvements were observed in all main clinical scores including Rankin, ONLS, and MRC testing (p < .01). Electrophysiological studies (EDX) revealed a predominantly motor neuropathy with marked reduction in CMAP in the lower limbs at baseline, and no significant improvement in motor parameters (p = .543). Rankin score at 6 months correlated with the initial weekly N 2 O consumption (r = .43, p = .03) and the CMAP sum score in the lower limbs at the first EDX (r = -.47, p = .02). Patients with and without myelitis showed similar Rankin and ONLS score after 6 months., Interpretation: The clinical course generally improved favorably at 6 months with notable amelioration in the primary disability scores, sensory deficits, and ataxia. However, distal motor impairment associated with peripheral neuropathy persisted, with distal axonal loss emerging as the main prognostic factor for long-term disability in these young patients., (© 2024 Peripheral Nerve Society.)

Introduction: A variety of labor pain management options is essential to patients and their care providers. Inhaled, patient controlled nitrous oxide (N 2 O) is a valuable addition to these options. The purpose of this study was to examine laboring patient, newborn, and provider characteristics associated with N 2 O use for pain relief in labor and to examine the association between N 2 O, conversion to neuraxial analgesia, and cesarean birth., Methods: This was a retrospective observational cohort study of the first year of N 2 O use in one large academic medical center. Patients at least 37 weeks' gestation who were admitted for labor with intended vaginal birth from August 1, 2018, to June 30, 2019, were included (N = 2605). Laboring patient and newborn factors and their relationship to N 2 O use were calculated as unadjusted and adjusted relative risks (RRs). Poisson regression was used to model the association between N 2 O use and subsequent use of neuraxial analgesia and type of birth for both nulliparous and multiparous patients., Results: Overall, 20.2% of patients used N 2 O during labor. Multiparous patients were 24% less likely to use N 2 O than nulliparous patients (RR, 0.76; 95% CI, 0.69-0.84). Use of N 2 O did not differ significantly between patients cared for by midwives compared with patients cared for by physicians (RR, 0.95; 95% CI, 0.90-1.00). In multivariable modeling, N 2 O use in multiparous patients was associated with a 17% decrease in use of neuraxial analgesia (RR, 0.83; 95% CI, 0.73-0.94). There was no association between N 2 O use and use of neuraxial analgesia in nulliparous patients (RR, 0.99; 95% CI, 0.93-1.06). N 2 O use was not associated with cesarean birth in either group., Discussion: N 2 O is an important pain management option for laboring patients and those who care for them. Study results may assist midwives, physicians, and nurses in counseling patients about analgesia options., (© 2024 by the American College of Nurse‐Midwives.)

Abstract A continuous rise in the global demand for palm oil has resulted in the large‐scale expansion of oil palm plantations and generated environmental controversy. Efforts to increase the sustainability of oil palm cultivation include the recycling of oil mill and pruning residues in the field, but this may increase soil methane (CH4) emissions. This study reports the results of yearlong field‐based measurements of soil nitrous oxide (N2O) and CH4 emissions from commercial plantations in North Sumatra, Indonesia. One experiment investigated the effects of soil‐water saturation on N2O and CH4 emissions from inorganic fertilizers and organic amendments by simulating 25 mm rainfall per day for 21 days. Three additional experiments focused on emissions from (a) inorganic fertilizer (urea), (b) combination of enriched mulch with urea and (c) organic amendments (empty fruit bunches, enriched mulch and pruned oil palm fronds) applied in different doses and spatial layouts (placed in inter‐row zones, piles, patches or bands) for a full year. The higher dose of urea led to a significantly higher N2O emissions with the emission factors ranging from 2.4% to 2.7% in the long‐term experiment, which is considerably higher than the IPCC standard of 1%. Organic amendments were a significant source of both N2O and CH4 emissions, but N2O emissions from organic amendments were 66%–86% lower than those from inorganic fertilizers. Organic amendments applied in piles emitted 63% and 71% more N2O and CH4, respectively, than when spread out. With twice the dose of organic amendments, cumulative emissions were up to three times greater. The (simulated) rainwater experiment showed that the increase in precipitation led to a significant increase in N2O emissions significantly, suggesting that the time of fertilization is a critical management option for reducing emissions. The results from this study could therefore help guide residue and nutrient management practices to reduce emissions while ensuring better nutrient recycling for sustainable oil palm production systems.

Abstract Nitrous oxide (N2O) is a potent greenhouse gas and major component of the net global warming potential of bioenergy feedstock cropping systems. Numerous environmental factors influence soil N2O production, making direct correlation difficult to any one factor of N2O fluxes under field conditions. We instead employed quantile regression to evaluate whether soil temperature, water‐filled pore space (WFPS), and concentrations of soil nitrate (NO3−) and ammonium (NH4+) determined upper bounds for soil N2O flux magnitudes. We collected data over 6 years from a range of bioenergy feedstock cropping systems including no‐till grain crops, perennial warm‐season grasses, hybrid poplar, and polycultures of tallgrass prairie species each with and without nitrogen (N) addition grown at two sites. The upper bounds for soil N2O fluxes had a significant and positive correlation with all four environmental factors, although relatively large fluxes were still possible at minimal values for nearly all factors. The correlation with NH4+ was generally weaker, suggesting it is less important than NO3− in driving large fluxes. Quantile regression slopes were generally lower for unfertilized perennials than for other systems, but this may have resulted from a perpetual state of nitrogen limitation, which prevented other factors from being clear constraints. This framework suggests efforts to reduce concentrations of NO3− in the soil may be effective at reducing high‐intensity periods—”hot moments”—of N2O production.

Abstract Anesthesia is frequently used to facilitate physiological monitoring during interventional animal studies. However, its use may induce cardiovascular (central and peripheral), respiratory, and thermoregulatory depression, confounding results in anesthetized animals. Despite the wide utility of guinea pigs as a translational platform, anesthetic protocols remain unstandardized for extended physiological studies in this species. Therefore, optimizing an anesthetic protocol that balances stable anesthesia with intact cardiorespiratory and metabolic function is crucial. To achieve this, 12 age and sex‐matched juvenile Dunkin Hartley guinea pigs underwent extended anesthesia (≤150 min) with either (a) isoflurane (ISO: 1.5%), or (b) isoflurane + N2O (ISO+ N2O: 0.8% +70%), in this randomized cross‐over designed study. Cardiovascular (HR, SBP, peripheral microvascular blood flow), respiratory (respiratory rate, SpO2), and thermal (Tre and Tsk) measures were recorded continuously throughout anesthesia. Blood gas measures pre‐ and post‐ anesthesia were performed. Incorporation of 70% N2O allowed for significant reductions in isoflurane (to 0.8%) while maintaining an effective anesthetic depth for prolonged noninvasive physiological examination in guinea pigs. ISO+N2O maintained heart rate, peripheral blood flow, respiratory rate, and thermoregulatory function at levels closest to those of conscious animals, especially in females; however, it did not fully rescue anesthesia‐induced hypotension. These results suggest that for studies requiring prolonged physiological examination (≤150 min) in guinea pigs, 0.8% isoflurane with a 70% N2O adjuvant provides adequate anesthesia, while minimizing associated cardiorespiratory depression. The preservation of cardiorespiratory status is most marked throughout the first hour of anesthesia.

Abstract The distribution, fate, and effects of antibiotics and heavy metal residues in agricultural soil caused by long‐term application of organic fertilizers are of increasing concern. However, the ecotoxic effects of the interaction between antibiotics and heavy metals vary with the physicochemical properties of the soil, and it is still unclear how these substances interact with soil microbial functions. A short‐term microcosm experiment was conducted to investigate effects of the typical antibiotic oxytetracycline (OTC) with heavy metals (zinc [Zn] and copper [Cu]) alone or in combination on nitrification process and soil microbial activity in two different types of soil (FQ: sandy loam soil and NB: clay loamy soil). Results indicated that soil types influenced the toxic effects of antibiotics and heavy metals. Zn and Cu alone and when combined with OTC inhibited and retarded nitrification processes and reduced nitrous oxide emissions, which were mainly attributed to the inhibitory effects on ammonia‐oxidizing microorganisms. Moreover, Zn and Cu alone or combined with OTC increased soil respiration, but decreased the abundances of bacteria and fungi. In contrast, OTC alone had no significant effect on soil respiration but increased the abundance of fungi in both soils. Together, our results suggest that the widespread occurrence of antibiotics and heavy metals in agriculture soils may pose significant eco‐environmental risks by altering nitrification process and soil microbial activity.

Abstract Reducing nitrous oxide (N2O) emissions from agriculture is critical to limiting future global warming. In response, a growing number of food retailers and manufacturers have committed to reducing N2O emissions from their vast networks of farmer suppliers by providing technical assistance and financial incentives. A key challenge for such companies is demonstrating that their efforts are leading to meaningful progress toward their climate mitigation commitments. We show that a simplified version of soil surface nitrogen (N) balance—or partial N balance—the difference between N inputs to and outputs from a farm field (fertilizer N minus crop N), is a robust indicator of direct N2O emissions from fields with maize and other major rainfed temperate‐region crops. Furthermore, we present a generalized environmental model that will allow food‐supply‐chain companies to translate aggregated and anonymized changes in average N balance across their supplying farms into aggregated changes in N2O emissions. This research is an important first step, based on currently available science, in helping companies demonstrate the impact of their sustainability efforts.

Background and Purpose: Nitrous oxide (N 2 O) induced neurological symptoms are increasingly encountered. Our aim is to provide clinical and diagnostic characteristics with a focus on electrodiagnostic studies., Methods: Patients with neurological sequelae due to N 2 O presenting in our hospital between November 2018 and December 2021 reporting clinical and diagnostic data were retrospectively reviewed., Results: Seventy patients (median 22 years) were included. Median N 2 O usage was 4 kg/week during 12 months. Patients' history revealed a higher rate of sensory symptoms compared to motor (97% vs. 57%) and 77% walking difficulties. Clinical diagnosis was polyneuropathy (PNP) in 44%, subacute combined degeneration (SCD) of the spine in 19%, both in 37%. Median vitamin B12 level was low (159 pmol/L), normal in 16%. The median methylmalonic acid was increased (2.66 μmol/L). Electrodiagnostic abnormalities were observed in 91%, with 72% fulfilling axonal PNP criteria, 20% showing mild to intermediate slowing. One patient fulfilled demyelinating PNP criteria not related to N 2 O abuse (Charcot-Marie-Tooth type 1a). More prominent motor nerve conduction abnormalities were found; lower limbs were more affected. In 64% with normal conduction, myography showed signs of axonal loss. Magnetic resonance imaging showed cervical myelopathy in 58% involving generally five to six segments., Conclusions: Nitrous oxide (N 2 O) leads to neurological symptoms by causing PNP and/or SCD primarily involving the legs. Distinguishing PNP and SCD clinically was shown to be insufficient. Electrodiagnostic studies showed axonal PNP. Demyelinating PNP due to N 2 O abuse was not present in our cohort. Therefore, further diagnostic work-up is warranted if demyelinating features are present., (© 2023 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Abstract Through the microbial breakdown of organic matter and production of greenhouse gases (GHGs), small agricultural dams or ponds have recently been shown to make a relatively large contribution to freshwater ecosystem carbon cycling. However, current estimates of their total carbon dioxide‐equivalent (CO2‐e) emissions lack inclusion of both seasonal and diel fluctuations. In addition, the atmospheric emissions of nitrous oxide from these often eutrophic systems have yet to be established. Here, we quantified the diffusive winter emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from 12 small agricultural dams within southeast Australia over a 24‐h period. The winter CO2‐e emissions of small agricultural water bodies were ~92% lower than previous summer estimates, at 1.02 g·m−2·d−1, while N2O contributed just 3.2% of this total. We also show that diel cycles do not significantly affect winter CO2, CH4, or N2O emission rates, and we discuss the likely carbon sources to these systems, through analyses of stable carbon isotopes (δ13C). The results from this study fill key gaps in our knowledge of agricultural dam GHG production and global atmospheric emissions, aiding their inclusion into future GHG budgets.

Abstract Anthropogenic activities have altered the nitrogen cycle, necessitating management on the landscape level. Isolated time periods and areas, termed hot moments and hot spots, respectively, frequently account for a large percentage of nitrate removal in aquatic ecosystems. A series of experiments were conducted to determine the effect of hydrologic connectivity on denitrification rates, gene abundances, and nitrous oxide fluxes. Experimental areas were divided into flooded (always inundated), floodzone (intermittently inundated), and nonfloodzone (not inundated) locations in low‐organic and organic‐rich soil. Our results demonstrate that intermittent flood events enhance denitrification rates from days to weeks after flooding, depending on the inundation period. Microbial analysis demonstrated that short‐term flood events did not lead to increases in denitrifying gene abundances. Enhanced denitrification rates did not have a corresponding increase in the ratio of incomplete to complete denitrification. Incomplete to complete denitrification ratios were high in always‐inundated low‐organic sandy soil, peaking at 40%. Our results suggest that management strategies that promote hydrologic connectivity and intermittent flooding of organic‐rich floodplain soils promote the formation of denitrification hot moments and hot spots, with relatively low incomplete denitrification (

Background: Recreational use of nitrous oxide (N 2 O) has dramatically increased in recent years, resulting in numerous cases of acute sensorimotor tetraparesis secondary to nitrous oxide-induced neuropathy (N 2 On). Challenging clinical features can mimic Guillain-Barré syndrome (GBS), the main differential diagnosis upon admission. The most sensitive biomarkers for distinguishing between these two conditions remain to be determined., Methods: Fifty-eight N 2 On patients from three referral centers were retrospectively included over a 2-year period and compared to GBS patients hospitalized during the same timeframe (47 patients). Collected demographic, clinical, biological, and electrophysiological data were compared between the two groups., Results: The typical N 2 On clinical pattern included distal sensorimotor deficit in lower limbs with absent reflexes, proprioceptive ataxia, and no cranial involvement (56.7% of our cohort). Misleading GBS-like presentations were found in 14 N 2 On patients (24.1%), and 13 patients (22.4%) did not report N 2 O use during initial interview. Only half the N 2 On patients presented with reduced vitamin B12 serum levels upon admission. A slightly increased cut-off (<200 pmol/L) demonstrated 85.1% sensitivity and 84.5% specificity in distinguishing N 2 On from GBS. Only 6.9% of N 2 On patients met the criteria for primary demyelination (p < 0.01), with only one presenting conduction blocks. A diagnostic algorithm combining these two biomarkers successfully classified all GBS-like N 2 On patients., Conclusions: Vitamin B12 serum level < 200 pmol/L cut-off and conduction blocks in initial electrophysiological study are the two most sensitive biomarkers for rapidly distinguishing N 2 On from GBS patients. These two parameters are particularly useful in clinically atypical N 2 On with GBS-like presentation., (© 2023 European Academy of Neurology.)