Ammonia Concentration Research Articles

Ammonia gas sensors based on multi-wall carbon nanofiber field effect transistors by using gate modulation

Ammonia gas sensors play a critical role in environmental monitoring and healthcare applications due to the harmful effects of ammonia exposure. In this study, I present a novel approach to ammonia detection using field-effect transistors (FETs) based on Multi-Wall Carbon Nanofibers (MWCNFs), known for their outstanding electrical properties. I fabricate and characterize MWCNF-FET sensors, utilizing interdigitated Source-Drain electrodes directly deposited onto aligned semiconducting MWCNFs. By systematically investigating the effect of gate bias on sensor performance, I demonstrate that applying a positive gate voltage enhances the sensor's gas response by up to 55 % across varying concentrations of ammonia. Additionally, I show that appropriate gate modulation significantly improves the device's reversibility, ensuring reliable, repeatable measurements. These findings highlight the potential of MWCNF-FETs in developing high-performance, gate-tunable ammonia gas sensors for real-world applications.

Seasonal variability of epipelic microphytobenthos community in two subtidal areas of the Northern Adriatic Sea

We investigated the biodiversity and seasonality of subtidal benthic diatoms at two sites of the Northern Adriatic Sea differently affected by anthropogenic inputs. Sediment samples were collected seasonally, and diatom cells were then separated from the sediment using the density gradient centrifugation method. The total abundance of benthic diatoms ranged between 4,409 ± 1,638 and 77,663 ± 30,415 cells cm-2 and the biomass between 0.41 ± 0.22 and 3.66 ± 2.01 μg C cm-2. At both stations, the benthic diatoms showed a marked seasonal pattern, with maximum abundance, biomass and biodiversity in spring and minimum in summer. Motile life forms, such as Navicula, Nitzschia, Fallacia, and Psammodictyon, dominated in terms of abundance at both stations throughout the study period, while plocon (centric diatoms mainly belonging to Biddulphiaceae) increased under mixing conditions, when they represented the largest contributor to biomass. At both stations and in all seasons, the Si:N:P ratio highlighted the strong P limitation, typical of the Adriatic Sea. The ammonium concentration was the highest component of DIN in spring and summer when we observed the highest and lowest MPB abundance respectively. The preference of diatoms for ammonia, coupled with the increased daylight period, may have enhanced the spring growth, whereas in summer the hypoxic conditions may have caused a decrease. Despite the different environmental conditions, the two stations exhibited similar species compositions and seasonal trends, highlighting relative stability against anthropogenic pressures of a different nature.

Restoring degraded lands: the role of sewage sludge in modulating soil carbon and nitrogen dynamics

Sewage sludge presents significant amounts of organic matter and nutrients and is frequently considered an alternative input for recovering degraded soils. In this scenario, this study aimed to evaluate the impacts of disposing of increasing doses of sewage sludge on the dynamics of C and N in the soil of a degraded area. After the application of five doses of sewage sludge (0, 50, 100, 200, and 400 t ha-1) were evaluated over time (30, 90, 180, 270, and 360 days), the contents of soil C and N, microbial biomass, light organic matter, and humic fractions of soil organic matter. The results showed that sewage sludge contributed to the quality and recovery of degraded soil by providing increases in soil organic C, total N, nitrate, and ammonia contents, microbial biomass C and N, light organic matter, as well as in the C and N stocks in humic substances, especially in humin. Most of the increases in these variables associated with C and N dynamics remained even one year after the application of sewage sludge. The soil quality improvement demonstrates the potential of using sewage sludge in projects to recover degraded areas as an alternative for its final disposal.

Methane Production Is More Sensitive to Temperature Increase than Aerobic and Anaerobic Methane Oxidation in Chinese Paddy Soils.

Methane emissions from paddy fields can increase under future warming scenarios. Nevertheless, a comprehensive comparison of the temperature sensitivity of methane-related microbial processes remains elusive. Here, we revealed that the temperature sensitivity of methane production (activation energy (Ea) = 0.94 eV; 95% confidence interval (CI), 0.78-1.10 eV) and aerobic (Ea = 0.49 eV; 95% CI, 0.34-0.65 eV) and anaerobic (Ea = 0.46 eV; 95% CI, 0.30-0.62 eV) methane oxidation exhibited notable spatial heterogeneity across 12 Chinese paddy fields spanning 35° longitude and 18° latitude. In addition, the Ea values of aerobic and anaerobic methane oxidation were significantly positively and negatively correlated to the latitude, respectively, while there was no significant correlation between the Ea of methane production and the latitude. Overall, there were no soil factors that had a significant effect on the Ea of methane production. The Ea of aerobic methane oxidation was primarily influenced by the contents of ammonium and clay, whereas the Ea of anaerobic methane oxidation was mainly influenced by the conductivity. Despite the variation, the overall temperature sensitivity of methane production was significantly higher than that of oxidation at a continental scale; therefore, an increase in the emission of methane from paddy fields will be predicted under future warming. Taken together, our study revealed the characteristics of temperature sensitivity of methane production and aerobic and anaerobic methane oxidation simultaneously in Chinese paddy fields, highlighting the potential roles of soil factors in influencing temperature sensitivity.

Measurement report: Urban ammonia and amines in Houston, Texas

Abstract. Ammonia and amines play critical roles in secondary aerosol formation, especially in urban environments. However, fast measurements of ammonia and amines in the atmosphere are very scarce. We measured ammonia and amines with a chemical ionization mass spectrometer (CIMS) at the urban center in Houston, Texas, the fourth most populated urban site in the United States, during October 2022. Ammonia concentrations were on average four parts per billion by volume (ppbv), while the concentration of an individual amine ranged from several parts per trillion by volume (pptv) to hundreds of pptv. These reduced nitrogen compounds were more abundant during weekdays than on weekends and correlated with measured CO concentrations, implying they were mostly emitted from pollutant sources. Both ammonia and amines showed a distinct diurnal cycle, with higher concentrations in the warmer afternoon, indicating dominant gas-to-particle conversion processes taking place with the changing ambient temperatures. Studies have shown that dimethylamine is critical for new particle formation (NPF) in the polluted boundary layer, but currently there are no amine emission inventories in global climate models (as opposed to ammonia). Our observations made in the very polluted area of Houston, as well as a less polluted site (Kent, Ohio) from our previous study (You et al., 2014), indicate there is a consistent ratio of dimethylamine over ammonia at these two sites. Thus, our observations can provide a relatively constrained proxy of dimethylamine using 0.1 % ammonia concentrations at polluted sites in the United States to model NPF processes.

Effect of bedding application and air change rates on environmental ammonia concentrations for intensively housed beef cattle

Context Manure deposition during livestock export voyages contributes to air ammonia levels, potentially affecting human and animal health if not managed. Mitigation strategies may include increased air change rates and application of bedding. Aim This study examined the effect of bedding application rate (BAR) and air change rate (ACH) on air ammonia (NH3) concentrations and pad properties, including pad surface condition, pH, moisture, and pad ammonium (NH4+) concentrations, for intensively housed beef cattle. Methods Six 7-day runs were conducted with 72 Bos indicus cross steers (mean liveweight ± s.d. = 338 ± 32 kg) housed in respiration chambers by using a 3 × 3 factorial design. The BARs were set to 0%, 50%, and 100% of the Australian Standards for the Export of Livestock (ASEL), and ACH were varied at 20, 35, and 52. Air NH3 was measured twice daily at three heights. Pad surface condition was collected with the first air NH3 measurement. Video footage captured standing and lying behaviours for each steer. Pad samples were collected on the final day for pad chemical analysis. Key results The ACH of 20 changes per hour resulted in higher air NH3 concentration than ACH of 35 and 52. Higher BAR led to lower pad pH and moisture, with slightly lower pad NH4+ concentration in 100% and 50% BAR than 0% BAR. Although air NH3 concentration on Day 7 was positively correlated with pad NH4+ concentration, BAR had no marked effect on air NH3 concentration (within the temperature range of this experiment). Drier and firmer pad surfaces were associated with each high BAR and high ACH. Moreover, high BAR increased the frequency of lying behaviour in steers. Conclusions These findings indicated that NH3 can be mitigated by optimising air changes to minimise air NH3 concentration and utilising bedding to minimise pad NH4+. This offers practical solutions for intensively housed beef cattle, such as livestock export voyages to improve human and animal welfare onboard. Implications The study results emphasised the importance of optimising ACH to maintain low air NH3 concentrations in livestock export conditions. Although there was no evidence that BAR affects air NH3 directly, it reduced pad NH4+ and improved pad conditions for overall animal comfort and environmental quality in confined housing with sufficient air changes.

Correction: A Higher Stomatal Aperture is Associated with the Growth Promotion of Centipedegrass (Eremochloa ophiuroides (Munro) Hack.) Under High Concentrations of Ammonium

Correction: A Higher Stomatal Aperture is Associated with the Growth Promotion of Centipedegrass (Eremochloa ophiuroides (Munro) Hack.) Under High Concentrations of Ammonium

Long-lifespan, biodegradable, self-disinfecting, and gas-sensing electronic mask with a Janus-structured all-natural fiber network for personal healthcare

Conventional disposable surgical masks have become an integral part of our daily lives, however, present a limited filtration efficiency, brief operative lifespan, and inability to degrade naturally, bringing a heavy burden to the environment. Moreover, these masks cannot efficaciously eliminate bacteria, potentially causing secondary and cross infections among users, thereby failing to curb the spread of infectious diseases. Herein, a fire-new, long-lifespan, biodegradable, self-disinfecting, and gas-sensing electronic-mask is nano-engineered with a Janus-structured all-natural fiber network (SA-CPN) constructed from animal-collagen and plant-fibers. SA-CPN demonstrates exceptional filtration performance (99.9%) for PM2.5 and maintains outstanding filtration efficiency after 10 test-cycles or 32 h in high-humidity conditions. SA-CPN exhibits robust antibacterial origins for extended periods, with antibacterial rates of 98.30%, 99.36%, and 98.11% against P aeruginosa, S aureus, and E coli, respectively, and can effectively filter airborne bacterial aerosols. Moreover, SA-CPN achieves real-time detection of ammonia concentrations, effectively identifying ammonia levels in exhaled human breath and external environments, and monitoring the human respiratory rate, potentially identifying underlying health conditions. The directional water vapor transmission capability of SA-CPN improves comfort when wearing. Notably, SA-CPN can fully biodegrade within 5 h under enzyme action. The proposed multifunctional electronic mask, featuring biocompatibility, biodegradability, self-disinfection, and ammonia sensing capabilities, holds significant promise in personal medical protective equipment for health monitoring and disease prevention.

Influence of NH3 flow rate on the photoelectric properties of high Al content p-AlGaN.

High Al content (60%) p-AlGaN with different NH3 flow rates was grown using metal-organic chemical vapor deposition (MOCVD), and changes in its photoelectric properties were studied using the Hall effect tester (Hall) and cathodoluminescence (CL) spectrometer. The results show that the film resistivity increases from 3.8 Ω·cm to 46.5 Ω·cm with increasing NH3 flow rate. The impurity peak intensity of p-AlGaN grown under high NH3 flow conditions is particularly high, indicating numerous point defects. The results of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) show a large number of Ga interstitial atoms (Gai) at the interface. As Gai acts as a donor, this may be the main reason for the increase in resistivity. And under high NH3 flow conditions, a lattice distortion and a high density of dislocation occur between p-AlGaN and p-GaN, which can lead to enhanced carrier scattering and decreased mobility. Additional validation via LED growth experiments indicates that the luminescence intensity of samples with low ammonia concentration increased by more than 13000 times.

Hydrogeochemical dynamics under saltwater-freshwater mixing in a mangrove wetland over tidal cycles

Seawater and groundwater interactions shape the hydrogeochemical profile of mangrove aquifers, revealing how biogeochemical processes adapt to saline-freshwater mixing via the fluctuating patterns of key hydrochemical indicators and primary biogenic elements. This study, utilizing a multi-level monitoring profile spanning the entire submerged aquifer within a mangrove wetland, analyzed the spatiotemporal dynamics of DO, ORP, pH, alkalinity and biogenic elements (C, N, S). The results revealed that among the basic hydrochemical parameters, total alkalinity showed the most stable spatiotemporal distribution and was positively correlated with salinity. pH demonstrated a significant negative correlation with salinity, whereas the correlations of ORP and DO with salinity were not substantial. The discharge of terrestrial freshwater into the mangrove wetland is marked by hydrogeochemical reactions favoring the input of Mg2+ and DIC, with potential iron mineral precipitation within the aquifer. Spatial distribution of biogenic elements in the groundwater showed no apparent pattern across sampling periods. DOC concentrations ranged from 0.3 to 1.3 mmol/L. Three components of dissolved organic matter were identified using three-dimensional fluorescence spectroscopy, with high molecular weight components (C1 + C2) accounting for an average of 47 to 73 %. Both elevated DOC concentrations and high molecular weight component ratios were primarily found in shallow layers of dense mangrove areas, decreasing with depth. Concentrations of ammonia, nitrite, and nitrate varied dynamically, reflecting active biochemical processes in the shallow to mid-layers of the aquifer. Furthermore, sulfate and sulfide concentrations, ranging from 0 to 26 mmol/L and 0.4 to 576.8 μmol/L, respectively, underscore the interplay of biogeochemical reactions, especially sulfate reduction. These findings highlight valuable insights into the complex biogeochemical processes within mangrove aquifers and provide theoretical guidance for protecting the ecological health of mangrove wetlands.

Machine learning reveals dynamic controls of soil nitrous oxide emissions from diverse long-term cropping systems.

Soil nitrous oxide (N2O) emissions exhibit high variability in intensively managed cropping systems, which challenges our ability to understand their complex interactions with controlling factors. We leveraged 17 years (2003-2019) of measurements at the Kellogg Biological Station Long-Term Ecological Research (LTER)/Long-Term Agroecosystem Research (LTAR) site to better understand the controls of N2O emissions in four corn-soybean-winter wheat rotations employing conventional, no-till, reduced input, and biologically based/organic inputs. We used a random forest machine learning model to predict daily N2O fluxes, trained separately for each system with 70% of observations, using variables such as crop species, daily air temperature, cumulative 2-day precipitation, water-filled pore space, and soil nitrate and ammonium concentrations. The model explained 29%-42% of daily N2O flux variability in the test data, with greater predictability for the corn phase in each system. The long-term rotations showed different controlling factors and threshold conditions influencing N2O emissions. In the conventional system, the model identified ammonium (>15 kg N ha-1) and daily air temperature (>23°C) as the most influential variables; in the no-till system, climate variables such as precipitation and air temperature were important variables. In low-input and organic systems, where red clover (Trifolium repens L.; before corn) and cereal rye (Secale cereale L.; before soybean) cover crops were integrated, nitrate was the predominant predictor of N2O emissions, followed by precipitation and air temperature. In low-input and biologically based systems, red clover residues increased soil nitrogen availability to influence N2O emissions. Long-term data facilitated machine learning for predicting N2O emissions in response to differential controls and threshold responses to management, environmental, and biogeochemical drivers.

Apoptosis-stimulating protein of p53 (ASPP) participates in the regulation of apoptosis in Litopenaeus vannamei under ammonia-N and nitrite-N stress

Apoptosis-stimulating protein of p53 (ASPP) is a key regulatory factor closely related to p53 in apoptosis pathway. To further investigate the molecular mechanisms of ASPP in Litopenaeus vannamei, the expression of LvASPP mRNA under ammonia-N and nitrite-N stress was explored, and the effects of knocking out LvASPP on mortality, histological damage, and the apoptosis pathway in L. vannamei under ammonia-N and nitrite-N stress were investigated. Healthy L. vannamei (7.78 ± 0.70 g) were used in this study. After shrimp were stressed with an ammonia-N concentration of 30.00 mg/L for 48 h, qRT-PCR was used to detect a significant increase in LvASPP mRNA expression in the hepatopancreas, gills, and muscle. Following 48 h of nitrite-N stress at a concentration of 60.00 mg/L, LvASPP mRNA expression was significantly increased in the hepatopancreas. The survival rate notably increased under 80 h of ammonia-N stress (25.00 mg/L) after LvASPP RNA interference (30 % more than the control group), and the number of shrimp deaths decreased after 48 h of nitrite-N stress. Moreover, under the stress of ammonia-N and nitrite-N respectively, LvASPP silencing reduced the expression of p53, and led to a decrease in the expression of apoptosis-related genes (Bax, Apaf-1, Caspase 9, MDM2). Caspase 3 activity, TUNEL-positive cells and the apoptotic index in the hepatopancreas markedly reduced under ammonia-N and nitrite-N stress. The potential pathway suggests that inhibiting LvASPP reduces the mRNA expression of p53, which leads to a decrease in Caspase 3 activity, inhibiting apoptosis in the hepatopancreatic cells of L. vannamei under ammonia-N and nitrite-N stress. These data indicate that the knockdown of LvASPP positively impacted the tolerance of L. vannamei to ammonia-N and nitrite-N stress by regulating the apoptosis pathway. This suggests that employing gene-targeted dsRNA could be an effective strategy for alleviating the environmental pressures faced by shrimp in aquaculture management.

Replacing soybean meal with house cricket (Acheta domesticus) meal in ruminant diet: effects on ruminal fermentation, degradation, and biohydrogenation

Abstract Insect meals could be a sustainable protein source in ruminant diets to overcome the environmental, market, and feed-food-fuel issues associated with the widespread use of soybean meal (SBM). However, research on this topic is still very scarce. This study was conducted to examine the possibility of replacing SBM with house cricket (Acheta domesticus) meal (HCM) in ruminant feeding. Four cannulated sheep were fed a total mixed ration containing either 10% SBM (Control diet) or 10% of non-defatted HCM (Insect diet) over two consecutive periods. Effects on ruminal fermentation, degradation, and biohydrogenation were evaluated. Despite some differences in rumen dry matter and N degradation kinetics, replacing dietary SBM with HCM did not affect the ruminal disappearance of dry matter, N and, neutral detergent fibre of in situ incubated feedstuffs. Nor were there differences between the meals in the in vitro intestinal digestibility of rumen non-degraded nitrogen. The replacement had no negative effects on rumen pH or ammonia concentrations, but resulted in lower total and individual (i.e. acetate, propionate, butyrate, and minor) volatile fatty acid concentrations. This adverse effect was probably due, at least in part, to the unexpectedly high content of fat in HCM and its relatively high degree of unsaturation. Inclusion of HCM in the diet facilitated modulation of the fatty acid profile of the rumen digesta without negative effects on biohydrogenation pathways (e.g. it increased trans-11 18:1 and cis-9 trans-11 CLA concentrations, with only a small variation in the trans-10:trans-11 18:1 ratio). Replacing SBM with HCM in ruminant diets could be a promising alternative to address the challenges related to SBM and to improve the lipid composition of ruminant-derived products. However, further research is still needed to investigate, for example, the most appropriate level of inclusion of HCM in the diet or the use of defatted meal.

Archaeal community from the Northern Hangzhou Bay to the East China Sea: biogeography, ecological processes, and functional potential

IntroductionArchaeal communities play a crucial role in marine ecosystems, yet our understanding of their ecological and functional traits remains incomplete. This study focuses on northern Hangzhou Bay to fill gaps in knowledge regarding the biogeography and functionality of archaeal groups.MethodsWe utilized a high-throughput sequencing dataset based on the 16S rRNA gene to characterize the archaeal community, aiming to identify biogeographic patterns and assess the influence of environmental factors on community structure.ResultsThe predominant phyla identified were Woesearchaeota, Thaumarchaeota, Euryarchaeota, and Crenarchaeota. Archaeal community structure in sediments showed a geographical pattern along the environmental gradient, influenced by factors such as salinity, ammonium, total phosphorus, pH, and total nitrogen content. Network analysis revealed nonrandom co-occurrence patterns, with associations changing along the salinity gradient. Additionally, this study directly proved the existence of dispersal limitation in this strongly connected marine ecological system through null model analyses. Variation in the archaeal community was attributed to both environmental constraints and stochastic processes due to dispersal limitation. Furthermore, our results revealed that the key biogeochemical functions of the archaeal community also exhibited a clear salinity gradient, the functional differences appear to be influenced by salinity, and the critical roles of archaeal diversity were highlighted.DiscussionAll these findings enhance our understanding of microbial ecology and element transformation in estuarine environments. The highlighted roles of archaeal diversity and the influence of environmental factors on community structure and function underscore the complexity of marine microbial ecosystems.

Nitrite manipulation in water by structure change of plasma electrolysis reactor

In this study, experimental reactors for cathodic nitrogen plasma electrolysis were designed by the composition of galvanic (voltaic) and electrolytic cells with wide and narrow connectors filled with tap water and agar solutions. The designed reactor can be used to simultaneously perform and manage nitrification in acidic and alkaline environments. According to the reactor’s performance, it can be installed on the irrigation system and used depending on the soil pH of the fields for delivering water and nitrogen species that are effective in growth. The nitrification process was investigated by choosing the optimal reactor with a wide connector based on different changes in oxidation-reduction potential and pH on the anode and cathode sides. The nitrite concentration changed directly with ammonium and nitrate concentrations on the cathode side. It changed inversely and directly with ammonium and nitrate concentrations on the anode side respectively. Nitrite concentration decreased from 5.387 ppm with water connector, to 0.326 ppm with 20% agar solution, and 0.314 ppm with 30% agar solution connectors on the anode side. It increased from 0 ppm to 0.191 ppm with a water connector, 0.405 ppm with 20% agar solution, and 7.454 ppm with 30% agar solution connectors on the cathode side.

Recovering Nitrogen from Anaerobic Membrane Bioreactor Permeate Using a Natural Zeolite Ion Exchange Column

In the framework of a circular economy, wastewater treatment should be oriented toward processes that allow the recovery of the resources present in the wastewater while ensuring good effluent quality. Nitrogen recovery is usually carried out in streams concentrated in this nutrient because these high concentrations facilitate nitrogen valorization. On the other hand, the mainstream of a wastewater treatment plant (WWTP) has a high potential for nitrogen recovery, but it is not usually considered because it is hard to manage due to its low nitrogen concentration. To solve this problem and facilitate the recovery of nitrogen in the mainstream, this work proposes ion exchange with zeolites as a stage of ammonium concentration, to provide a nitrogen-concentrated stream that could be valorized by another technology, while obtaining a nitrogen-free effluent. The working stream, the permeate of an AnMBR process in the mainstream, has suitable characteristics to be treated in an ion exchange column (free of suspended solids and with very low organic matter content). To this end, the effect of the working flow rate (17.5 to 4.4 BV/h) and the ammonium concentration (54 to 17 mg NH4-N/L) on the adsorption capacity of the zeolite in the loading phase was evaluated. The adsorption curves were fitted to three mathematical models: Thomas, Bohart–Adams, and Yoon–Nelson. The effect of the regeneration flow rate (from 8.7 to 2.2 BV/h) and the regenerant concentration (NaOH at 0.2, 0.1, and 0.05 M) on regeneration capacity and efficiency were also studied. A novel control strategy based on effluent conductivity was used in both phases to control the duration of the adsorption and regeneration phases.

Enhanced ammonia sensing performance of NiFe2O4 and dysprosium doped NiFe2O4 for advanced Environmental Monitoring

Air pollution driven by rapid technological growth, has heightened mortality rates and infectious diseases, prompting research into advanced gas-sensing materials. This study examined the gas sensing properties of NiFe2O4 and dysprosium-doped NixDy1-xFe2O4 (x = 0.02, 0.04, 0.06) under ammonia concentrations of 10–100 ppm. The incorporation of Ni2+ ions into the Fe2O4 lattice revealed p-type semiconductor behaviour. Notably, NixDy1-xFe2O4 (x = 0.06) exhibited superior ammonia sensing, with high sensitivity and excellent selectivity. Stability tests confirmed its robustness, maintaining 83.8% of its initial response, highlighting its potential for effective ammonia detection.

Evaluating the Importance of Nitrate‐Containing Aerosols for the Asian Tropopause Aerosol Layer

AbstractThe Asian Summer Monsoon (ASM) convection transports aerosols and their precursors from the boundary layer to the upper troposphere and lower stratosphere (UTLS). This process forms an annually recurring aerosol layer near the tropopause. Recent observations have revealed a distinct property of the aerosol layer over the ASM region, it is nitrate‐rich. We present a newly implemented aerosol formation algorithm that enhances the representation of nitrate aerosol in the Community Aerosol and Radiation Model for Atmospheres (CARMA) coupled with the Community Earth System Model (CESM). The simulated aerosol chemical composition, as well as vertical distributions of aerosol size and mass, are evaluated using in situ and remote sensing observations. The simulated concentrations (ammonium, nitrate, and sulfate) and size distributions are generally within the error bars of data. We find nitrate, organics, and sulfate contribute significantly to the UTLS aerosol concentration between 15°–45°N and 0°–160°E. The two key formation mechanisms of nitrate‐containing aerosols in the ATAL are ammonium neutralization to form ammonium nitrate in regions where convection is active, and condensation of nitric acid in regions of cold temperature. Furthermore, including nitrate formation in the model doubles the surface area density in the tropical tropopause region between 15°–45°N and 0°–160°E, which alters the chlorine partitioning and subsequently impacts the rate of ozone depletion.

A-132 Next generation ammonia reagent with improved reagent composition and assay performance

Abstract Background Ammonia is produced by catabolism of protein and other compounds which contain nitrogen. Elevated ammonia levels are toxic for the central nervous system. High plasma ammonia is a prognostic factor for hepatic and kidney disease or inherited metabolic disorders in urea cycle metabolism. The reliable and accurate quantification of ammonia is influenced by assay, reagent, and sample management. Current commercially available GLDH enzyme-based ammonia assay reagents experience high bias between matched Lithium Heparin and K2-EDTA samples, poor accuracy, imprecision at the low end, large HIL (hemolysis, icterus and lipemia) interferences and shorter shelf life. To improve upon the listed deficiencies, we developed an improved GLDH based ammonia assay in a two-part format with improved reagent composition. Methods Ammonia reagent in 2-part format R1 and R2 were assessed for accuracy, precision, interference by HIL reportable range, sensitivity (LoB, LoD, LoQ), shelf life, matched matrix comparison (Lithium Heparin vs K2-EDTA) and method comparison. All testing were performed using Li Heparin plasma samples in Beckman DxC700AU analyzer. Accuracy was tested using Verichem ammonia standards which are ACS ammonia standard material. Twenty-day precision studies were performed using three levels of ammonia concentrations using Bio-Rad Liquichek Ammonia controls and plasma samples. Interference was tested in two ammonia concentrations (40-50 µmol/L) and (200-250 µmol/L) using commercially available spiking material for clinical chemistry assays such as conjugated and unconjugated bilirubin, Intralipid and in-house prepared hemolysate. Infinity Ammonia Reagent on Beckman Coulter AU Chemistry Analyzers was used for method comparison studies Results Next generation ammonia showed good accuracy with Verichem ammonia standards and acceptable within-run and total precision. Studies showed significant improvement in sensitivity and longer shelf life (>18 months). Next generation ammonia is less affected by interferences from icterus (100 mg/dL), lipemia (1000 mg/dL intralipid) and hemolysis (100 mg/dL). Comparison studies show no significant bias between match Lithium Heparin and K2-EDTA matched samples. Conclusions Next Generation Ammonia reagent showed very good overall performance required for reliable and accurate quantification of ammonia in human plasma sample.

Optimizing Sugarcane Clonal Propagation In Vitro by Using Calcium Ammonium Nitrate and Ammonium Sulfate.

To replace explosive nitrate-based chemicals in MS medium, this study developed a new, safer, and more cost-effective method using fertilizer-grade calcium ammonium nitrate and ammonium sulfate. This approach replaces ammonium nitrate and potassium nitrate, ensuring both safety and cost efficiency for sugarcane propagation. Six local sugarcane varieties-Zhongtang1 (ZT1), Zhongtang3 (ZT3), Zhongtang6 (ZT6), Guitang42 (GT42), Guitang44 (GT44), and Guiliu 07150 (GT07150)-were used. In the control group (Ck), nitrate ions (NO3-) were 39.28 mM, and ammonium ions (NH4+) were 20.49 mM, with a 2:1 ratio. In the treatment groups, the concentrations of nitrate ions (NO3-) and ammonium ions (NH4+) included treatment 1 (19.69 mM NO3- and 10.3 mM NH4+), treatment 2 (29.54 mM and 15.44 mM), treatment 3 (39.38 mM and 20.59 mM), treatment 4 (49.225 mM and 25.74 mM), treatment 5 (59.07 mM and 30.89 mM), and treatment 6 (68.915 mM and 36.03 mM), respectively, all with the same 2:1 ratio. Fifty bottles per treatment, with three replicates, were used for each sugarcane plantlets treatment. After five subcultures, the optimal ratio was determined by assessing morphological and physiological parameters, nitrogen levels, and SOD enzyme activity. The results indicated that treatment 3 (39.38 mM and 20.59 mM) and treatment 4 (49.225 mM and 25.74 mM) had the best morphological and physiological indicators. The optimal doses of calcium ammonium nitrate and ammonium sulfate were found in treatments 3 and 4, as well as in the control, with no significant difference among them. However, treatment 3, due to its lower dose, was more cost effective. To improve cost efficiency in practical production, it is recommended to use the lower concentration ratio of treatment 3 for plant tissue culture plantlets.