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This study aimed to use colloidal silver nanoparticles (AgNPs) for ammonium adsorption. Several factors were considered, including pH value, contact time, amount of adsorbent, and beginning ammonium content. The ideal parameters for ammonium adsorption onto the AgNPs were an a pH of 9, a contact period of 60 minutes, a concentration of 1.824 mg AgNPs/25 mL of ammonium solution, and a starting concentration of 80 mL, as determined. The optimum ammonium adsorption capacity onto the AgNPs was 276.84 mg/g, and the Langmuir model described the isotherm adsorption with R2, KL, and calculated qmax values of 0.9339, 0.518 L/mg, and 263.37 mg/g, respectively. The experimental data were most closely matched by the Elovich model, as seen by its R2, α, and β values of 0.885, 0.055, and 0.180, respectively. Temperature release values for the exothermic adsorption were 23,084 kJ/mol at 20°C, −23872 kJ/mol at 30°C, and 24,660 kJ/mol at 40°C. [ABSTRACT FROM AUTHOR]

The reaction of 4,6-di-tert-butyl-2,3-dihydroxybenzaldehyde with analogs of Girard's reagents was used to synthesize new water-soluble ammonium acylhydrazones as individual EC=N,synN-C(O) isomers. The introduction of an additional sterically hindered phenolic moiety into ammonium N-acylhydrazone leads to the emergence of antimicrobial activity against gram-negative pathogens of bacterial (Pseudomonas aeruginosa, Escherichia coli) and fungal origin (Candida albicans). [ABSTRACT FROM AUTHOR]

Under pressure from surface water pollution and climate change, groundwater becomes a critical water source. Information on groundwater quality could contribute to effective groundwater management. This study was carried out to utilize multivariate statistical analysis and the groundwater quality index (GWQI) to evaluate groundwater quality in Ca Mau Province, Vietnam. Twenty-five groundwater samples from residential-urban areas, cemetery areas, landfill areas, and saline intrusion areas were collected for this study. Groundwater quality was evaluated using the National Technical Regulation on Groundwater Quality (QCVN 09-MT:2015/BTNMT) and GWQI. Principal component analysis (PCA) was used to identify potential polluting sources and key variables influencing groundwater quality. Cluster analysis (CA) was applied to cluster groundwater quality, and the sites were recommended for future monitoring. The results revealed that NH4+-N contaminated groundwater in the landfill area, while the saline intrusion area was polluted by TDS and NH4 +-N. The groundwater quality classified as excellent, good, poor, and very poor accounted for 44, 40%, 12%, and 4%, respectively. Cluster analysis divided groundwater quality into four groups, mainly based on the presence of NH4 +-N and TDS. Nine groundwater sampling locations could be removed from the current groundwater quality program but still ensuring representativeness as a result of CA. PCA proposed two main sources of variation in groundwater quality at each residential-urban area: the cemetery area, the landfilling area, and the saline intrusion area. The groundwater parameters (i.e., pH, TDS, permanganate index, NH4+-N, NO3--N, and Fe) should be continued to monitor. Domestic and industrial wastewater discharge, leachate from cemeteries and landfills, the nature of groundwater aquifers, and seawater intrusion could be potential sources of groundwater variation. The current findings provide scientific information for local environmental authorities to manage and monitor groundwater quality in the study area. [ABSTRACT FROM AUTHOR]

Excess existence of ammonium in water bodies is a hazard to aquatic health. Recent studies demonstrated the use of pig manure biochar (PBC) as a potential adsorbent for ammonium removal. This study investigates alteration in the adsorption capability of modified PBCs to ammonium. Modifications were done by immersing PBC in different acid/alkaline mediums such as H2SO4 HCl, NaOH, KOH, and FeSO4. Adsorption kinetics of modified PBC to ammonium was studied and compared. Also, physical characteristics of these modified biochars were analyzed using BET, SEM, XRD, and FTIR to explore the ammonium adsorption mechanism. The adsorption capacity of ammonia nitrogen was improved for PBCKOH and PBCHCl, whereas it was found to decrease for other modified biochars. The improvement is likely due to an increase in specific surface area and pore size as well as formation of active functional groups and ions during the modification process. While both pseudo-first-order kinetics (R2 > 0. 9) and pseudo-second-order (R2 > 0.9) kinetics could fit the adsorption kinetic data well, among modified biochars, PBCFeSO4 and PBCH2S04 fit better with pseudo-first-order model, while others fit pseudo-second-order model better. Both Langmuir and Freundlich model were in good agreement with the adsorption isotherm data for raw and modified biochars (R2 > 0.9). Variation in the adsorption capacity of ammonia nitrogen by different modified PBC might be due to synthesis of both physical and chemical factors. This study will lay a theoretical foundation for the future exploration of modification treatments of pig manure biochar for adsorption of ammonia nitrogen from wastewater. [ABSTRACT FROM AUTHOR]

Plant growth and resilience to abiotic stresses, such as soil salinity and drought, depend intricately on nitrogen metabolism. This review explores nitrogen's regulatory role in plant responses to these challenges, unveiling a dynamic interplay between nitrogen availability and abiotic stress. In the context of soil salinity, a nuanced relationship emerges, featuring both antagonistic and synergistic interactions between salinity and nitrogen levels. Salinity-induced chlorophyll depletion in plants can be alleviated by optimal nitrogen supplementation; however, excessive nitrogen can exacerbate salinity stress. We delve into the complexities of this interaction and its agricultural implications. Nitrogen, a vital element within essential plant structures like chloroplasts, elicits diverse responses based on its availability. This review comprehensively examines manifestations of nitrogen deficiency and toxicity across various crop types, including cereals, vegetables, legumes, and fruits. Furthermore, we explore the broader consequences of nitrogen products, such as N2O, NO2, and ammonia, on human health. Understanding the intricate relationship between nitrogen and salinity, especially chloride accumulation in nitrate-fed plants and sodium buildup in ammonium-fed plants, is pivotal for optimizing crop nitrogen management. However, prudent nitrogen use is essential, as overapplication can exacerbate nitrogen-related issues. Nitrogen Use Effi- ciency (NUE) is of paramount importance in addressing salinity challenges and enhancing sustainable crop productivity. Achieving this goal requires advancements in crop varieties with efficient nitrogen utilization, precise timing and placement of nitrogen fertilizer application, and thoughtful nitrogen source selection to mitigate losses, particularly urea-based fertilizer volatilization. This review article delves into the multifaceted world of plant nitrogen metabolism and its pivotal role in enabling plant resilience to nutritional stress and abiotic challenges. It offers insights into future directions for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Ammonium dinitramide (ADN), which has the advantages of high energy density, no halogen and low characteristic signal, is not only considered as a new high-energy oxidizer that is expected to replace the traditional oxidizer ammonium perchlorate (AP) in solid propellants, but also a good performance explosive in itself. However, due to the strong hygroscopicity of ADN, its application in solid propellants and explosives is greatly limited. Solving the hygroscopicity of ADN is the key to realize the wide application of ADN. In this paper, we systematically review the research progress of anti-hygroscopic strategies of ADN coating. The surface coating methods are focusing on solvent volatilization, solventnon- solvent, melt crystallization and atomic layer deposition technology. The characteristics of the different methods are compared and analyzed, and the basis for the classification and selection of the coating materials are introduced in detail. In addition, the feasibility of material for surface coating of ADN is evaluated by several compatibility analysis methods. It is highly expected that the liquid phase method (solvent volatilization method, solvent-non-solvent method) would be the promising method for future ADN coating because of its effective, safety and facile operation. Furthermore, polymer materials, are the preferred coating materials due to their high viscosity, easy adhesion, good antihygroscopic effect, and heat resistance, which make ADN weak hygroscopicity, less sensitive, easier to preserve and good compatibility. [ABSTRACT FROM AUTHOR]

Abstract: Organic Na-montmorillonite (OMt-12-2-12·2Y–, Y=CH3CO3 – , C6H5COO– ) modified by a series of Gemini quaternary ammonium surfactants with different counterions was prepared for enhancing the adsorption capacity of methyl orange. Compared with the initial adsorption capacity of 5.251 mg/g of Na-Mt, the adsorption effect of OMts under the optimal conditions increased by about 31~34 times. The adsorption isotherms and kinetics of all adsorption processes were respectively described by Langmuir and pseudo-second-order models. The structure, hydrophobicity and hydration of the counterions, as well as the affinity of the counterions with the long aliphatic chains, had a certain influence on the adsorption performance of OMts for methyl orange. [ABSTRACT FROM AUTHOR]– ) modified by a series of Gemini quaternary ammonium surfactants with different counterions was prepared for enhancing the adsorption capacity of methyl orange. Compared with the initial adsorption capacity of 5.251 mg/g of Na-Mt, the adsorption effect of OMts under the optimal conditions increased by about 31~34 times. The adsorption isotherms and kinetics of all adsorption processes were respectively described by Langmuir and pseudo-second-order models. The structure, hydrophobicity and hydration of the counterions, as well as the affinity of the counterions with the long aliphatic chains, had a certain influence on the adsorption performance of OMts for methyl orange. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effect of soil salinity on nitrogen mineralization in the presence and absence of wheat straw in three soils with textural classes of clay, loam and loamy sand under laboratory conditions as a factorial arrangement based on a completely randomized design with 3 replications. The studied factors were salinity (1, 10, 20 and 30 dS/m), wheat straw (0 and 2% by weight with C/N=89.5) and time (2, 5, 12, 20, 28, 37, 46, 53, 64, 73, 85 and 90 days). After investigation of different Iranian agricultural soils, three soils with low salinity (0.84-1.1 dS/m) and low organic carbon (0.22-0.98%) were selected. Considering the results, in the three soils, the amount of ammonium and nitrate in the treatment without straw was higher than those in the treatment with straw. In straw treatment, there was an initial descending trend in the amount of ammonium and nitrate for the three soils, but after a period of time, ammonium and nitrate content of the soil showed an ascending trend and returned to the initial value. With increasing soil salinity, the amount of soil ammonium increased in clay and loamy sand soils but decreased in the loamy soil. Nitrate content showed a descending trend for the three soils with increasing salinity. In general it is concluded that the presence of wheat straw in the soil can mitigate the negative effects of high concentrations of salt on nitrogen mineralization and reduce nitrogen losses. Introduction Soil salinity is one of the main factors of land degradation and decrease the yield of agricultural crops, affecting the population of soil microorganisms and soil dissolved organic carbon, plays an important role in soil nitrogen mineralization. Application of organic matter is often suggested as a solution to stimulate soil microbial activities in the soils affected by salt. Objective The present study was performed to investigate the effect of soil salinity on nitrogen mineralization in the presence and absence of wheat straw in three soils with textural classes of clay, loam and loamy sand under laboratory conditions. Materials and methods For this purpose, agricultural soil samples from different regions of Iran were investigated and three soils with low salinity (0.84-1.1 dS/m) and organic carbon (0.22-0.98%) were selected. The experiment was conducted as a factorial in a completely randomized design with the factors of salinity (initial salinity about 1, 10, 20 and 30 dS/m), wheat straw (two levels of 0 and 2% by weight with C/N=89.5) and time (2, 5, 12, 20, 28, 37, 46, 53, 64, 73, 85 and 90 days) by applying three repetitions for each sample. Results In addition to wheat straw, soil texture also has an effect on nitrogen mineralization, so that in clay and sandy loam soil without wheat straw, the ammonium content of the soil increased with increasing salt concentration, while in loamy soil without wheat straw, with increase soil salinity the amount of ammonium produced decreased. In all three soils, the amount of ammonium and nitrate in the treatment without straw was higher than in the treatment with straw. In the treatment with straw, there was an initial downward trend in the amount of ammonium and nitrate for all three soils, but after a period of time, the amount of ammonium and nitrate in the soil showed an upward trend and returned to the initial value. With the increase in soil salinity, the amount of soil ammonium increased in clay and loamy sand but decreased in loam soil, but the amount of soil nitrate showed a decreasing trend for all three soils with increasing salinity. Conclusion The results showed that soil salinity can lead to a decrease in soil mineral nitrogen by affecting the process of nitrogen mineralization, and the presence of wheat straw, although in a certain period of time, leads to a decrease in soil mineral nitrogen, but with the positive characteristics it gives to the soil, it can adjust the negative effects of high salt concentrations in the processes of ammonium and nitrate production in all of the three types of soil texture and on the other hand, reduce its losses by controlling the rate of nitrogen mineralization. Therefore, based on the results of this research, it is recommended to return wheat straw in saline soils along with calculating the nitrogen factor. The presence of wheat straw in saline soils can moderate the negative effects of high salt concentrations on nitrogen mineralization and reduce its losses. [ABSTRACT FROM AUTHOR]

Nitrate (NO3−) and ammonium (NH4+) are the primary forms of nitrogen (N) taken up by plants and can exhibit different effects on plant nutrition, photosynthesis, and growth. The objective was to investigate the influence of nitrate/ammonium proportions (%) on the nutritional status, photosynthetic parameters, and the development of Cedrela odorata seedlings after 150 days of cultivation. We tested six nitrate/ammonium ratios (100/0; 80/20; 60/40; 40/60; 20/80; and 0/100 of NO3− and NH4+, respectively), plus a control treatment (without N supply). Based on the results, the species responds to the supply of N; however, the NO3− and NH4+ proportions did not show any significant effect on plant growth. The deficiency of nitrogen (N) in Cedrela odorata decreases the photosynthetic rate, nutrient absorption, and initial growth of this species. Increasing the proportion of N in the form of nitrate inhibited the absorption of S (sulfur) but did not interfere with the accumulation of N, Ca (calcium), Mg (magnesium), Mn (manganese), Zn (zinc), B (boron), and Cu (copper). Cedrela odorata apparently does not distinguish between nitrate and ammonium in the N absorption process, since the proportions between these forms of N did not affect its photosynthetic rate, nutrient accumulation, or growth. [ABSTRACT FROM AUTHOR]

This study assessed the impact of the method of conducting the biofiltration process on the efficiency of ammonium nitrogen removal from water in combined sorption and nitrification processes. The research was carried out on diatomite deposits using biofiltration with gravity and counter-gravity flow. The following physicochemical water parameters were controlled during the research, including ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, and dissolved oxygen. Unconventional flow turned out to be more beneficial because it allows for optimal use of the entire bed surface, natural regulation of the biofilm thickness, and maintaining constant microbiological activity of the biofilm. The automatic regulation of the biofilm thickness during water flow prevented excessive growth of dead organic matter and limited the development of heterotrophic bacteria. Biofiltration with counter-gravity flow also resulted in reduced oxygen consumption. Regardless of the flow direction used, water after the single-stage biofiltration process was characterized by an increased content of nitrite nitrogen. The introduction of the second stage of filtration made it possible to obtain water that meets the requirements for water intended for human consumption. [ABSTRACT FROM AUTHOR]

Introduction: Global climate change exerts a significant impact on the nitrogen supply and photosynthesis ability in land-based plants. The photosynthetic capacity of dominant grassland species is important if we are to understand carbon cycling under climate change. Drought stress is one of the major factors limiting plant photosynthesis, and nitrogen (N) is an essential nutrient involved in the photosynthetic activity of leaves. The regulatory mechanisms responsible for the effects of ammonium (NH4-) and nitrate (NO3-) on the drought-induced photoinhibition of photosystem II (PSII) in plants have yet to be fully elucidated. Therefore, there is a significant need to gain a better understanding of the role of electron transport in the photoinhibition of PSII. Methods: In the present study, we conducted experiments with normal watering (LD), severe drought (MD), and extreme drought (HD) treatments, along with no nitrogen (N0), ammonium (NH4), nitrate (NO3), and mixed nitrogen (NH4NO3) treatments. We analyzed pigment accumulation, reactive oxygen species (ROS) accumulation, photosynthetic enzyme activity, photosystem activity, electron transport, and O-J-I-P kinetics. Results: Analysis showed that increased nitrate application significantly increased the leaf chlorophyll content per unit area (Chlarea) and nitrogen content per unit area (Narea) (p< 0.05). Under HD treatment, ROS levels were lower in NO3-treated plants than in N0 plants, and there was no significant difference in photosynthetic enzyme activity between plants treated with NO3 and NH4NO3. Under drought stress, the maximum photochemical efficiency of PSII (Fv/Fm), PSII electron transport rate (ETR), and effective quantum yield of PSII (ϕPSII) were significant higher in NO3-treated plants (p< 0.05). Importantly, the K-band and G-band were higher in NO3-treated plants. Discussion: These results suggest that drought stress hindered the formation of NADPH and ATP in N0 and NH4-treated L. chinensis plants, thus damaging the donor side of the PSII oxygen-evolving complex (OEC). After applying nitrate, higher photosynthetic enzyme and antioxidant enzyme activity not only protected PSII from photodamage under drought stress but also reduced the rate of damage in PSII during the growth of L. chinensis growth under drought stress. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of salinity on elemental sulfur-driven autotrophic denitrification (SAD) efficiency, and microbial communities. The results revealed that when the salinity was≤6 g/L, the nitrate removal efficiency in SAD increased with the increasing salinity reaching 95.53% at 6 g/L salinity. Above this salt concentration, the performance of SAD gradually decreased, and the nitrate removal efficiency decreased to 33.63% at 25 g/L salinity. Approximately 5mg/L of the hazardous nitrite was detectable at 15 g/L salinity, but decreased at 25 g/L salinity, accompanied by the generation of ammonium. When the salinity was ≥15 g/L, the abundance of the salt-tolerant microorganisms, Thiobacillus and Sulfurimonas, increased, while that of other microbial species decreased. This study provides support for the practical application of elemental sulfur-driven autotrophic denitrification in saline nitrate wastewater. [ABSTRACT FROM AUTHOR]

A novel method has been developed to use ammonium tetrafluoroborate (NH4BF4) directly as catalyst in Biginelli reaction. A new paradigm of the Biginelli reaction for the synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones derivatives found the use of ammonium tetrafluoroborate as a novel, inexpensive, readily available, non‐toxic and mild catalyst in good to excellent yields. Notably, this is the first time that ammonium tetrafluoroborate is directly used as a catalyst in organic synthesis. So far, no organic reaction is available in literature where NH4BF4 is directly used as catalyst. However, some reactions are found where NH4BF4 is used with other catalysts as promoters or additives. The protocol developed has several advantages, such as highly efficient, simple, atom‐economical, environmentally friendly, easy synthetic and purification methods. [ABSTRACT FROM AUTHOR]

The presence of ammonium (NH4+) in natural waters has increased in the last years due to the rising use of agricultural fertilizers, industrial activity and sewage discharges without any decontamination treatment. The great amounts of this inorganic cation in water bodies have been considered an environmental problem, due to its influence on the eutrophication process which leads to the deterioration of water quality. The application of ZnO nanoparticles to assess nutrient elimination, including ammonium, from water bodies has not been exhaustively studied. In this work, the capability of ZnO nanoparticles to remove ammonium cation from aqueous samples induced by adsorption is investigated. In this regards, experiments tending to determine the efficiency of nanomaterials have been performed employing two different NH4+ concentrations aiming to replicate two feasible real water-impacted environments. The interactions between adsorbent and adsorbate have been explored by employing experimental characterization techniques as well as theoretical DFT simulations. The achieved data demonstrated that the efficiency of ZnONPs shows a dependency on the ammonium concentration, ranging between 0.79 and 11.6 mg of ammonium adsorbed per gram of ZnONPs. According to the data on characterization prior and post adsorption of the ZnO nanomaterials the electrostatic interaction would not be favored, being the coordination ones the most feasible as suggested experimental and DFT results. [ABSTRACT FROM AUTHOR]

The access of vinasse leachates to water bodies and groundwater exacerbates environmental problems, especially eutrophication. Therefore, a column experiment was performed to examine the effect of adding zeolite (ZL), bone char (BC), and wood chips biochar (WCB) in the presence of vinasse on carbon dioxide (CO2) emission, leaching dissolved organic carbon (DOC) and ammonium (NH4+) in calcareous sandy soil, as well as studying the kinetics of leaching dissolved organic carbon and ammonium. This column experiment contains four treatments: soil alone (CK), soil + zeolite (SZL), soil + bone char (SBC), and soil + wood chips biochar (SWCB). These amendments were applied to the soil at a level of 4%. Vinasse was added to all treatments at a level of 13 mL per column. The leached total cumulative DOC and total cumulative soluble ammonium amounts decreased significantly with applying ZL, BC, and WCB compared with the soil alone. The effectiveness of these amendments in lowering the total cumulative DOC leaching is in the order of SBC > SWCB > SZL > CK. However, the effectiveness of these amendments in decreasing the total cumulative NH4+ leaching is in the order of SZL > SWCB > SBC > CK. The rate constant (k) of DOC leaching decreased significantly with the application of bone char compared to soil alone treatment. In the presence of vinasse, the apparent half-life of leached DOC from the soil was 8.1, 12.9, 36.7, and 15.5 days for soil CK, SZL, SBC, and SWCB treatments, respectively. Half-life values of leached soluble ammonium from the soil in the presence of vinasse addition were 10.1, 39.5, 28.5, and 37.9 days for CK, SZL, SBC, and SWCB treatments, respectively. Amending soil with BC increased significantly the phosphorus availability, however, applying ZL and BC caused a significant increase in the available potassium in calcareous sandy soil compared to the control treatment. According to these results, it is recommended not to add vinasse alone to sandy soils, but it is preferred to be co-applied with BC amendment at the level of 4% better than ZL and WCB. This would decrease leaching DOC and ammonium to the water table and groundwater as well as enhance nutrient retention in the soil, which in turn, plays a vital role in reducing the harmful effect of vinasse and improving soil fertility. [ABSTRACT FROM AUTHOR]

Little is known about the effect of nitrogen nutrition on seedling susceptibility to seed-borne pathogens. We have previously shown that seedlings grown under high nitrate (5 mM) conditions are less susceptible than those grown under low nitrate (0.1 mM) and ammonium (5 mM) in the Arabidopsis-Alternaria brassicicola pathosystem. However, it is not known how seedling metabolism is modulated by nitrogen nutrition, nor what is its response to pathogen infection. Here, we addressed this question using the same pathosystem and nutritive conditions, examining germination kinetics, seedling development, but also shoot ion contents, metabolome, and selected gene expression. Nitrogen nutrition clearly altered the seedling metabolome. A similar metabolomic profile was observed in inoculated seedlings grown at high nitrate levels and in not inoculated-seedlings. High nitrate levels also led to specific gene expression patterns (e.g., polyamine metabolism), while other genes responded to inoculation regardless of nitrogen supply conditions. Furthermore, the metabolites best correlated with high disease symptoms were coumarate, tyrosine, hemicellulose sugars, and polyamines, and those associated with low symptoms were organic acids (tricarboxylic acid pathway, glycerate, shikimate), sugars derivatives and β-alanine. Overall, our results suggest that the beneficial effect of high nitrate nutrition on seedling susceptibility is likely due to nutritive and signaling mechanisms affecting developmental plant processes detrimental to the pathogen. In particular, it may be due to a constitutively high tryptophan metabolism, as well as down regulation of oxidative stress caused by polyamine catabolism. [ABSTRACT FROM AUTHOR]

Layered two‐dimensional (2D) perovskites are emerging as promising optoelectronic materials owing to their excellent environmental stability. Regulating the dipole moment of organic spacers has the potential to reduce the exciton binding energy (Eb) of 2D perovskites and improve their photovoltaic performance. Here, we developed two azetidine‐based secondary ammonium spacers with different electron‐withdrawing groups, namely 3‐hydroxyazatidine (3‐OHAz) and 3,3‐difluoroazetidine (3,3‐DFAz) spacers, for 2D Ruddlesden‐Popper (RP) perovskites. It was found that the large dipole moment of the fluorinated dipole spacer could effectively enhance the interaction between organic spacers and inorganic layers, leading to improved charge dissociation in 2D RP perovskite. In contrast to 3‐OHAz spacer, the 2D perovskite using 3,3‐DFAz as spacer also shows improved film quality, optimized energy level alignment, and reduced exciton binding energy. As a result, the 2D perovskite (n=4) device based on 3,3‐DFAz yields an outstanding efficiency of 19.28 %, surpassing that of the 3‐OHAz‐Pb device (PCE=11.35 %). The efficiency was further improved to 19.85 % when using mixed A‐site cation of MA0.95FA0.05. This work provides an effective strategy for modulating the energy level alignment and reducing the Eb by regulating the dipole moment of organic spacers, ultimately enabling the development of high‐performance 2D perovskite solar cells. [ABSTRACT FROM AUTHOR]

Big Soda Lake, Nevada, is a multi‐extreme meromictic lake, whose hypersaline hyperalkaline bottom waters feature permanent anoxia and high concentrations of arsenic, sulphide and ammonia. These properties make Big Soda Lake—and the adjacent Little Soda Lake—a fascinating system for exploring life's boundaries, discovering novel microbial taxa and identifying biotechnologically useful strains. To date, the taxonomic diversity and metabolic capabilities of microorganisms in this system remain largely unknown. Here, we fill this gap using microbiome surveys across the Big and Little Soda Lake water columns, including 16S rRNA sequencing, fungal ITS2 sequencing and gene‐ and genome‐resolved metagenomics. We accompany these surveys with measurements of salinity, pH, temperature, oxygen, ammonium and ammonia concentrations. Our analyses reveal rich bacterial communities, taxonomically and functionally differentiated along Big Soda Lake's oxycline and, to lesser extent, between lakes. Fungal communities were dominated by a small number of families, while nearly no archaea were detected. Pathways related to perchlorate reduction, anoxygenic phototrophy, fermentation, dissimilatory metabolism of arsenite/arsenate, sulphur compounds, nitrogen compounds and hydrogen, were particularly prevalent. A total of 129 high‐quality bacterial and archaeal metagenome‐assembled genomes (completeness ≥ 80%, contamination ≤ 5%) were recovered, yielding insight into the taxonomic distribution of microbial metabolic pathways. [ABSTRACT FROM AUTHOR]

Coastal and estuarine waters of the northern California Current system and southern Salish Sea host an observational network capable of characterizing biogeochemical dynamics related to ocean acidification, hypoxia, and marine heatwaves. Here, we compiled data sets from a set of cruises conducted in estuarine waters of Puget Sound (southern Salish Sea) and its boundary waters (Strait of Juan de Fuca and Washington coast). This data product provides data from a decade of cruises with consistent formatting, extended data quality control, and multiple units for parameters such as oxygen with different end use needs and conventions. All cruises obtained high-quality temperature, salinity, inorganic carbon, nutrient, and oxygen observations to provide insight into the dynamic distribution of physical and biogeochemical conditions in this large urban estuary complex on the west coast of North America. At all sampling stations, conductivity–temperature–depth (CTD) casts included sensors for measuring temperature, conductivity, pressure, and oxygen concentrations. Laboratory analyses of discrete water samples collected at all stations throughout the water column in Niskin bottles provided measurements of dissolved inorganic carbon (DIC), dissolved oxygen, nutrient (nitrate, nitrite, ammonium, phosphate, and silicate), and total alkalinity (TA) content. This data product includes observations from 35 research cruises, including 715 oceanographic profiles, with >7490 sensor measurements of temperature, salinity, and oxygen; ≥6070 measurements of discrete oxygen and nutrient samples; and ≥4462 measurements of inorganic carbon variables (i.e., DIC and TA). The observations comprising this cruise compilation collectively characterize the spatial and temporal variability in a region with large dynamic ranges of the physical (temperature = 6.0–21.8 ∘ C, salinity = 15.6–34.0) and biogeochemical (oxygen = 12–481 µmolkg-1 , dissolved inorganic carbon = 1074–2362 µmolkg-1 , total alkalinity = 1274–2296 µmolkg-1) parameters central to understanding ocean acidification and hypoxia in this productive estuary system with numerous interacting human impacts on its ecosystems. All observations conform to the climate-quality observing guidelines of the Global Ocean Acidification Observing Network, the US National Oceanic and Atmospheric Administration's Ocean Acidification Program, and ocean carbon community best practices. This ongoing cruise time series supports the estuarine and coastal monitoring and research objectives of the Washington Ocean Acidification Center and US National Oceanic and Atmospheric Administration (NOAA) Ocean and Atmospheric Research programs, and it provides diverse end users with the information needed to frame biological impacts research, validate numerical models, inform state and tribal water quality and fisheries management, and support decision-makers. All 2008–2018 cruise time-series measurements used in this publication are available at 10.25921/zgk5-ep63 (Alin et al., 2022). [ABSTRACT FROM AUTHOR]

Protecting the population from aerosol pollution relies on forecasts using models with aerosol composition, yet the respective contributions of aerosol components are poorly known. In particular, the contribution of inorganic condensable particulate matter (PM) to aerosols is likely to be underestimated in most models because condensable particulate matter exceeds the amount of filterable particulate matter in emissions from stationary combustion sources. Moreover, condensable particulate matter is rarely included in current emission inventories. Here, we estimated the emissions of inorganic condensable particulate matter from stationary combustion sources based on monitoring information in China. Then we modeled the contributions of condensable particulate matter to simulated inorganic aerosols, e.g., sulfate, ammonium, and nitrate by designing a series of sensitivity simulation scenarios. The results show that the estimated emissions of inorganic components over mainland China are increased about five times after including inorganic condensable particulate matter, for both 2014 and 2017. Specifically, taking into account the inorganic condensable particulate matter, increased the average concentrations of sulfate by 104%, ammonium by 10%, nitrate by 11%, and PM2.5 by 21% for the Hangzhou site in December 2017. Similarly, the simulated average daily concentrations of sulfate from December 3 to 31, 2017, more than doubled, increasing from 3.17 to 8.41 μg m−3 for Gucheng, 7.70 to 16.75 μg m−3 for Chengdu, 4.08 to 9.43 μg m−3 for Lin'an, and 3.19 to 7.22 μg m−3 for Dalian. [ABSTRACT FROM AUTHOR]

Biostimulation through the enrichment of indigenous ureolytic bacteria has been proven to be a feasible approach for implementing microbially induced carbonate precipitation (MICP). To apply this method to real-world engineering situations, researchers are focusing on (1) increasing the cementation content to improve the mechanical performance of biocemented sand, and (2) minimizing the negative impact of ammonium, a harmful byproduct. In this study, biochars of different shapes (powdered or flaked) were used as additives in calcareous sand. The effects of biochar on shear strength improvement and ammonium removal were investigated through isotropically consolidated drained (CD) triaxial shear tests, as well as ammonium adsorption and leaching tests, respectively. Experimental results indicated that biochar positively impacted cementation content, particularly for powdered biochar with smaller particle sizes, which enhanced shear strength in CD tests. Microscopic analysis of biochar-amended biocemented sand revealed that biochar can serve as additional nucleation sites for precipitation. Moreover, the contributions of friction, dilatancy, and mobilized cohesion of biocemented sand at peak strength and in the maximum dilatancy state were elucidated. Furthermore, biochar demonstrated significant ammonium removal under both aqueous and sand column conditions. These findings hold practical significance for the stabilization of local calcareous sand, as well as for other coastal cities worldwide. [ABSTRACT FROM AUTHOR]

SUMMARY: In natural and agricultural situations, ammonium (NH4+) is a preferred nitrogen (N) source for plants, but excessive amounts can be hazardous to them, known as NH4+ toxicity. Nitrate (NO3−) has long been recognized to reduce NH4+ toxicity. However, little is known about Brassica napus, a major oil crop that is sensitive to high NH4+. Here, we found that NO3− can mitigate NH4+ toxicity by balancing rhizosphere and intracellular pH and accelerating ammonium assimilation in B. napus. NO3− increased the uptake of NO3− and NH4+ under high NH4+ circumstances by triggering the expression of NO3− and NH4+ transporters, while NO3− and H+ efflux from the cytoplasm to the apoplast was enhanced by promoting the expression of NO3− efflux transporters and genes encoding plasma membrane H+‐ATPase. In addition, NO3− increased pH in the cytosol, vacuole, and rhizosphere, and down‐regulated genes induced by acid stress. Root glutamine synthetase (GS) activity was elevated by NO3− under high NH4+ conditions to enhance the assimilation of NH4+ into amino acids, thereby reducing NH4+ accumulation and translocation to shoot in rapeseed. In addition, root GS activity was highly dependent on the environmental pH. NO3− might induce metabolites involved in amino acid biosynthesis and malate metabolism in the tricarboxylic acid cycle, and inhibit phenylpropanoid metabolism to mitigate NH4+ toxicity. Collectively, our results indicate that NO3− balances both rhizosphere and intracellular pH via effective NO3− transmembrane cycling, accelerates NH4+ assimilation, and up‐regulates malate metabolism to mitigate NH4+ toxicity in oilseed rape. [ABSTRACT FROM AUTHOR]

The accurate determination of uranium content in geological samples is extremely important for the exploration and development of uranium resources. In this study, based on titration method for the determination of uranium content of the nuclear industry standard test, the pretreatment process such as sample dissolution, sample dissolution reagent and test method has been improved according to the characteristics of geological samples. The results showed that the sample was moistened with water before acid treatment, and the dissolving vessel was adjusted from 100 mL beaker to 150 mL triangle flask, which basically avoided the problem of sputtering during the boiling process. The amount of phosphoric acid added in the sample dissolution reagent was increased to ensure that the ferrous could completely reduce the hexavalent uranium in the sample at the appropriate phosphoric acid concentration, and the low measurement result caused by the low phosphoric acid concentration is avoided. In the test, the amount of reducing agent ferrous sulfate is changed to 1 mL, and the amount of sodium nitrite was changed to 3–4 drops, which improved the sensitivity of titration endpoint and realized clear determination of titration end point. The RSD of the improved test method is better than 2.5%, and the standard recovery is between 99 and 102%. The results are accurate and reliable, can meet the needs of scientific research and production. It can provide technical support for uranium exploration and natural uranium production. [ABSTRACT FROM AUTHOR]

The previous studies have shown that iron–manganese co-oxide film (MeOx) could simultaneously remove ammonium, manganese ion and bisphenol A. In this study, the removal of fulvic acid (FA) was explored by adding potassium ferrate (K2FeO4) to heighten the catalytic activity of MeOx. After adding about 3.0 mg/L potassium ferrate, the elimination efficiency of 7.0 mg/L FA by the MeOx increased from 20 to 50%. The effects of temperature and ammonium on the elimination of FA were investigated. Higher temperature (above 22 °C) and higher ammonium concentration (above 2.0 mg/L) caused a decrease in FA removal. Most of FA combined with the ferric hydroxide colloid produced by K2FeO4 in water to form macromolecular groups, and they were subsequently absorbed and covered on the surface of MeOx. Scanning electron microscope showed that more viscous flocs appeared on the surface of MeOx, and the film thickness became thicker. Electron energy-dispersive spectrometer analysis revealed a notable increased in the C–O element ratio and a significant decreased in the Mn–Fe element ratio on the surface of MeOx. From Fourier transform infrared spectroscopy, the content of transition metal carbonyl compounds increased in the surface of MeOx. XPS analysis confirmed that the presence of Fe3O4, FeO, Mn2O3 and Mn3O4 along with functional group substances of FA attached on the surface of MeOx. The removal mechanism of FA was studied. [ABSTRACT FROM AUTHOR]

The development of propulsion systems based on green propellants, as an alternative to hydrazines, has been gaining interest within the space community. The study of Ammonium Dinitramide (ADN)-based liquid monopropellant, which is low-toxic and can deliver high performance, is the focal point of interest for Space Solutions Co., Ltd., Daejeon, Republic of Korea. A 1N ADN-based propulsion system was designed to evaluate the performance of the propellant. By combining a thermal and catalytic bed in a reactor, the performance of the propellant was examined in a designed thruster (chamber pressure of 11 bar). A total of 16 tests, with pulse mode experiments, were conducted; the accumulated firing time was 285 s. The preheating temperatures were maintained between 350 and 400 °C to achieve steady-state combustion. Notably, the maximum combustion efficiency was 91%. Test 9 recorded the highest decomposition temperature of propellant in the catalyst bed (1422 °C). Interestingly, the combustion instability observed throughout this study was ≤0.5%. This study could assist in the further development of ADN-based propulsion systems. [ABSTRACT FROM AUTHOR]

With the growth of industry and agriculture, nitrogenous compounds like nitrate and ammonium have contributed significantly to the contamination of groundwater. These pollutants cause intoxication and even may lead to stomach cancer. Permeable reactive barrier (PRB) is considered an in situ and low-cost method for groundwater treatment. This research aims to evaluate six different inexpensive reactive substances such as perlite and sand (1:1), cocopeat and sand (1:1), activated carbon, sawdust and sand (1:1), zeolite, and pumice for removing nitrate with an initial concentration of 100 mgL−1 and three reactive materials such as Leca, vermiculite and pumice (1:1), and cocopeat and pumice (1:1) for removing ammonium with two initial concentrations of 20 mgL−1 and 40 mgL−1 utilizing column experiments. Some of these absorbents have been rarely used in PRB to remove nitrogenous compounds. The plexiglass column utilized in column experiments and water flow through the layer in the column is due to the constant head difference. Results showed that all the reactive materials that have been used in removing nitrate had good performance with a minimum removal percentage above 73%. The best performance among these reactive substances belonged to a mixture of perlite and sand (1:1) with a maximum removal efficiency of 100%. The mixture of cocopeat and pumice (1:1) had the best performance among the materials were chosen for the ammonium treatment, with maximum removal percentages of 80% and 70% for initial concentrations of 20 mgL−1 and 40 mgL−1, respectively. Variations in the permeability coefficient of the reactive materials were investigated in this study, as an essential factor in the lifespan of the reactant during the column experiments. Results of constant head permeability tests revealed that a rapid drop was observed in the reactive layer's permeability coefficient during the period leading up to the maximum removal percentage and then a subsequent minor decline occurred. [ABSTRACT FROM AUTHOR]

The aim of this work was to assess effect of saturated constructed wetland-Microbial fuel cell system on dissolved oxygen gradient, electricity generation and ammonium removal. Two laboratory-scale systems, one planted with Schoenoplectus californicus (SCW1-MFC) and other without plant (SCW2-MFC), were fed discontinuously with synthetic wastewater over 90 days. Both systems were operated at different organic loading rate (12 and 28 g COD/m2d) and ammonium loading rate (1.6 and 3.0 g NH4+– N/m2 d) under open circuit and close circuit mode. The results indicate that between lower and upper zones of wetlands the average values were in the range of 1.22 ± 0.32 to 1.39 ± 0.27 mg O2/L in SCW1-MFC and 1.28 ± 0.24 to 1.56 ± 0.31 mg O2/L in SCW2-MFC. The effect of operating mode (closed and open circuit) and vegetation on DO was not significant (p > 0.05). Chemical oxygen demand (COD) removal efficiencies, fluctuated between 90 and 95% in the SCW1-MFC and 82 and 94% in the SCW2-MFC system. Regarding NH4+- N, removal efficiencies were above 85% in both systems reaching values maximus 98%. The maximum power density generated was 4 and 10 mW/m2 in SCW1-MFC, while SCW2-MFC recorded the highest values (12 and 22 mW/m2). [ABSTRACT FROM AUTHOR]

Dearomatization of quinoline/isoquinoline quaternary ammonium salts to synthesize valuable tetrahydroquinolines was firstly reported. Under this method, we used phenylsilane as a reducing agent to prepare a series of tetrahydroquinoline and tetrahydroisoquinoline derivatives conveniently and quickly in moderate to good yields. This method showed good functional group tolerance, wide substrate range, mild reaction conditions and simple operation. [ABSTRACT FROM AUTHOR]

Resin-based dental materials have been one of the ideal choices among various materials in the treatment of dental caries. However, resin-based dental materials still have some drawbacks, such as the lack of inherent antibacterial activity. Extensive research has been conducted on the use of novel quaternary ammonium monomers (QAMs) to impart antibacterial activity to dental materials. This review provides a comprehensive overview of the recent advances in quaternary ammonium monomers (QAMs) for dental applications. The current progress and limitations of QAMs are discussed based on the evolution of their structures. The functional diversification and enhancement of QAMs are presented. QAMs have the potential to provide long-term antibacterial activity in dental resin composites, thereby prolonging their service life. However, there is a need to balance antibacterial performance with other material properties and the potential impact on the oral microbiome and general health. Finally, the necessity for further scientific progress in the development of novel quaternary ammonium monomers and the optimization of dental resin formulations is emphasized. [ABSTRACT FROM AUTHOR]

Ammonium and polyamines are essential nitrogen metabolites in all living organisms. Crosstalk between ammonium and polyamines through their metabolic pathways has been demonstrated in plants and animals, while no research has been directed to explore this relationship in algae or to investigate the underlying molecular mechanisms. Previous research demonstrated that high concentrations of ammonium and putrescine were among the active substances in bacteria-derived algicide targeting dinoflagellates, suggesting that the biochemical inter-connection and/or interaction of these nitrogen compounds play an essential role in controlling these ecologically important algal species. In this research, putrescine, ammonium, or a combination of putrescine and ammonium was added to cultures of three dinoflagellate species to explore their effects. The results demonstrated the dose-dependent and species-specific synergistic effects of putrescine and ammonium on these species. To further explore the molecular mechanisms behind the synergistic effects, transcriptome analysis was conducted on dinoflagellate Karlodinium veneficum treated with putrescine or ammonium vs. a combination of putrescine and ammonium. The results suggested that the synergistic effects of putrescine and ammonium disrupted polyamine homeostasis and reduced ammonium tolerance, which may have contributed to the cell death of K. veneficum. There was also transcriptomic evidence of damage to chloroplasts and impaired photosynthesis of K. veneficum. This research illustrates the molecular mechanisms underlying the synergistic effects of the major nitrogen metabolites, ammonium and putrescine, in dinoflagellates and provides direction for future studies on polyamine biology in algal species. [ABSTRACT FROM AUTHOR]

A hydrophobic cationic-ionomer layer of quaternary ammonium poly(N-methyl-piperidine-co-p-terphenyl) and PTFE is presented to enhance the CO2 electroreduction in a zero-gap membrane electrode assembly (MEA) electrolyzer under acidic and low alkali ion concentration conditions. The modified MEA achieved a maximum CO faradaic efficiency of 95.6% at 100 mA cm−2. [ABSTRACT FROM AUTHOR]

It is generally accepted that hydrogen is generated by ferrous iron oxidation and/or water radiolysis but no attempt has been done so far to explain the origin of the nitrogen that is associated to 'hydrogen systems' such as those located in Brazil and Oman and New Caledonian ophiolites. We carried out 25–300 °C geochemical equilibrium calculations on model water and water-mineral systems including ammonium (NH 4 +) to see if this ion could be a 'precursor' in the generation of hydrogen and/or nitrogen. The considered minerals of the water-mineral systems were the magnetite-hematite or fayalite-magnetite-quartz redox-buffering assemblages. The water systems including NH 4 + only or NH 4 + and ferrous iron co-generate hydrogen and nitrogen through the ammonium decomposition reaction: NH 4 + = 1.5 H 2 + 0.5 N 2 + H+ In the water-mineral systems, hydrogen is generated by the magnetite and fayalite ferrous iron oxidation while nitrogen is generated independently by the hematite and magnetite ferric iron reduction by NH 4 +: 3 Fe3+ + NH 4 + = 0.5 N 2 + 3 Fe2+ + 4 H+ With magnetite-hematite, the produced gas is mainly composed of nitrogen. At low temperature with fayalite-magnetite-quartz, the produced gas is mainly composed of hydrogen; approaching 300 °C, and with a sufficient initial ammonium stock, a significant amount of nitrogen is produced to form a mixed gas. If we consider low (magnetite-hematite) or high (fayalite-magnetite-quartz) reducing conditions occurring respectively within the central or peripheral zones of the hydrogen systems, NH 4 + passing through and reacting with these two kinds of redox environments could explain why the central zones release mainly hydrogen (with some amounts of nitrogen) and why mainly nitrogen is emitted at the peripheries. • Modeling of ammonium oxidation in redox-unbuffered and -buffered aqueous systems. • Hydrogen and nitrogen co-generation through ammonium decomposition. • Nitrogen generation through ferric iron reduction by ammonium. • Hydrogen to nitrogen gas ratios as function of redox conditions. • Explanation of hydrogen and nitrogen association within natural hydrogen seepages. [ABSTRACT FROM AUTHOR]

• Drying of solid digestate was investigated in thin-layer at a laboratory-scale. • The kinetics of ammonium degradation and drying exhibited a similar characteristic. • Both processes occured in three similar distinguishable periods. • In the first reaction period, NH 4 -N degradation is a first-order chemical reaction. • The development of the pH value clearly followed the reaction course. Fundamental knowledge of the drying behavior and ammonia emission from digestate is required in order to properly design efficient drying processes. In this study, laboratory-scale drying experiments with two different digestates (D1 and D2) were conducted at four different drying temperatures (50, 60, 70, and 80 °C). The solid digestate D1 mainly consisted of plant silage (88.7%), while D2 comprised primarily of manure (55.9%). The drying experiments were performed in a controlled drying chamber using relatively small-sized samples of digestate (30 g for D1, 37 g for D2). These samples were characterized by an initial moisture content of about 74% wb (D1) and 78% wb (D2). This sample size mass was deliberately chosen to ensure homogeneous drying conditions within a thin layer and to facilitate precise laboratory quality measurements of parameters including water content, nitrogen contents (N-total, NH 4 -N), and pH values before and after the drying process. Both types of digestate exhibited a similar kinetics of drying and ammonium degradation. The first period of constant drying rate was followed by two periods with decreasing rates. Similarly, the ammonium degradation was characterized by three periods with decreasing reaction rates. Considering only the first reaction period herein, ammonium degradation was determined as a first-order reaction. The activation energy for this reaction period was obtained to be 20.00 kJ mol−1 for digestate D1 and 18.44 kJ mol−1 for digestate D2. The results of this study may serve as a basis for the conceptualization and design of optimized, continuous drying processes tailored to digestate materials. [ABSTRACT FROM AUTHOR]

The exchange of ammonium across cellular membranes is a fundamental process in all domains of life and is facilitated by the ubiquitous Amt/Mep/Rh transporter superfamily. Remarkably, despite a high structural conservation in all domains of life, these proteins have gained various biological functions during evolution. It is tempting to hypothesise that the physiological functions gained by these proteins may be explained at least in part by differences in the energetics of their translocation mechanisms. Therefore, in this review, we will explore our current knowledge of energetics of the Amt/Mep/Rh family, discuss variations in observations between different organisms, and highlight some technical drawbacks which have hampered effects at mechanistic characterisation. Through the review, we aim to provide a comprehensive overview of current understanding of the mechanism of transport of this unique and extraordinary Amt/Mep/Rh superfamily of ammonium transporters. [ABSTRACT FROM AUTHOR]

Refractive indices and optical birefringence of improper ferroelectric ammonium fluoroberyllate (AFB) crystals with the incommensurate phase are studied in a wide temperature range. Temperature characteristics of the optical indicatrix of AFB are examined and two quasi-isotropic points are found, the temperature positions T0 of which are almost independent of the light wavelength. Unlike the dielectric permittivity affected by the incommensurate-ferroelectric phase transition (PT) at TC, the optical characteristics of AFB are influenced only by the normal-incommensurate PT located at Ti ≈ 183.1 K. Using a Ginzburg criterion and the experimental Ginzburg number G ≈ 2.5×10-3, we have determined the temperature region around Ti where the critical fluctuations are small and a canonical mean-field theory can be applied. Outside the critical region, the spontaneous birefringence arising due to the incommensurate PT is described perfectly by the Landau theory, with the critical index of the order parameter β ≈ 0.50. [ABSTRACT FROM AUTHOR]

Mechanically robust anion-exchange membranes (AEMs) with high conductivity and long-term alkali resistance are needed for water electrolysis application. In this work, aryl-ether free polyaromatics containing isatin moieties were prepared via super acid-catalyzed copolymerization, followed by functionalization with alkaline stable cyclic quaternary ammonium (QA) cationic groups, to afford high performance AEMs for application in water electrolysis. The incorporation of side functional cationic groups (pyrrolidinium and piperidinium) onto a polymer backbone via a flexible alkyl spacer aimed at conductivity and alkaline stability improvement. The effect of cation structure on the properties of prepared AEMs was thoroughly studied. Pyrrolidinium- and piperidinium-based AEMs showed similar electrolyte uptakes and no obvious phase separation, as revealed by SAXS and further supported by AFM and TEM data. In addition, these AEMs displayed high conductivity values (81. 5 and 120 mS cm−1 for pyrrolidinium- and piperidinium-based AEM, respectively, at 80 °C) and excellent alkaline stability after 1 month aging in 2M KOH at 80 °C. Especially, a pyrrolidinium-based AEM membrane preserved 87% of its initial conductivity value, while at the same time retaining its flexibility and mechanical robustness after storage in alkaline media (2M KOH) for 1 month at 80 °C. Based on 1H NMR data, the conductivity loss observed after the aging test is mainly related to the piperidinium degradation that took place, probably via ring-opening Hofmann elimination, alkyl spacer scission and nucleophilic substitution reactions as well. The synthesized AEMs were also tested in an alkaline water electrolysis cell. Piperidinium-based AEM showed superior performance compared to its pyrrolidinium analogue, owing to its higher conductivity as revealed by EIS data, further confirming the ex situ conductivity measurements. [ABSTRACT FROM AUTHOR]

Carveol is a rare fine chemical with specific biological activities and functions in nature. The artificial synthesis of carveol from plentiful and cheap turpentine is expected to further improve development of pharmaceutical and industrial applications. A new green catalytic system for the preparation of high-value carveol from α-epoxypinane is presented. A novel ammonium salt solid acid (AC-COIMI-NH4PW) was obtained from phosphotungstic acid bonded with imidazole basic site on nitrogen-doped activated carbon which, after ammonia fumigation, presented an excellent catalytic performance for the selective rearrangement of α-epoxypinane to carveol in DMF as solvent under mild reaction conditions. At 90 °C for 2 h, the conversion of α-epoxypinane could reach 98.9% and the selectivity of carveol was 50.6%. The acidic catalytic sites exhibited superior durability and the catalytic performance can be restored by supplementing the lost catalyst. Based on the investigation of catalytic processes, a parallel catalytic mechanism for the main product was proposed from the rearrangement of α-epoxypinane on AC-COIMI-NH4PW. [ABSTRACT FROM AUTHOR]

Amino acid L-arginine (Arg), usually presented in food products and biological liquids, can serve both as a useful indicator of food quality and an important biomarker in medicine. The biosensors based on Arg-selective enzymes are the most promising devices for Arg assay. In this research, three types of amperometric biosensors have been fabricated. They exploit arginine oxidase (ArgO), recombinant arginase I (ARG)/urease, and arginine deiminase (ADI) coupled with the ammonium-chelating redox-active nanoparticles. Cadmium-copper nanoparticles (nCdCu) as the most effective nanochelators were used for the development of ammonium chemosensors and enzyme-coupled Arg biosensors. The fabricated enzyme/nCdCu-containing bioelectrodes show wide linear ranges (up to 200 µM), satisfactory storage stabilities (14 days), and high sensitivities (A⋅M−1⋅m−2) to Arg: 1650, 1700, and 4500 for ADI-, ArgO- and ARG/urease-based sensors, respectively. All biosensors have been exploited to estimate Arg content in commercial juices. The obtained data correlate well with the values obtained by the reference method. A hypothetic scheme for mechanism of action of ammonium nanochelators in electron transfer reaction on the arginine-sensing electrodes has been proposed. [ABSTRACT FROM AUTHOR]

The nitrite efficient utilization microorganism Wickerhamomyces anomalus RZWP01 was identified. Using nitrite and ammonium as the sole nitrogen source, the nitrogen removal rate of W. anomalus RZWP01 was 97.4% and 87.1%, respectively. W. anomalus RZWP01 grew well in the nitrite medium with glucose or xylose as the only carbon source. However, the W. anomalus RZWP01 cannot live on the nitrite medium with lactose, citric acid, and methanol as the only carbon source. The maximal cell concentration occurred in the nitrite medium with glucose as the only carbon source at a C/N ratio of 20 for 48 h, reaching 8.92 × 108 cell mL−1. W. anomalus RZWP01 was the first reported yeast that can efficiently utilize nitrite. The isolation and identification of W. anomalus RZWP01 enriched the microbial resources of nitrite-degrading microorganisms and provided functional microorganisms for the water treatment of sustainable aquaculture. [ABSTRACT FROM AUTHOR]

This article explores the applications of ammonium ylide based rearrangements in transforming amines into natural products. Specifically, it discusses the [2,3]-sigmatropic and [1,2]-Stevens rearrangements, which involve the exchange of carbon-nitrogen and carbon-carbon bonds. The article showcases the use of these rearrangements in the synthesis of natural products such as cephalotaxine and amathaspiramide F. It also discusses the synthesis of other complex molecules, including strictamine, 6-deoxytetracycline antibiotics, tylophorine, iboga alkaloids, vinblastine, and chiral indolizidines. The article emphasizes the efficiency and selectivity of these rearrangements in accessing bioactive polycyclic frameworks. Additionally, it explores the use of magnesium iodide and trimethyl phosphate in the synthesis of organic compounds. Overall, the article demonstrates the utility of ammonium ylide based rearrangements in the synthesis of diverse natural products. [Extracted from the article]

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Anaerobic digestion of sewage sludge is limited at the hydrolysis stage of the process. The goal of this study was to assess the effects of sludge retention times and ultrasound pretreatment on the ammonium concentration and organic matter transformation in anaerobic digesters treating sewage sludge. To achieve this, two laboratory-scale semicontinuous anaerobic digesters were operated for a period of over 70 d, including a control reactor and another fed by pretreated sludge. Both anaerobic systems were fed with mixed sludge (50%/50% primary/secondary treatment) in mesophilic conditions (37 °C), with solid retention times (SRT) of 7.5 d (Phase I) and 3 d (Phase II). The performance of the anaerobic digestion process was assessed in terms of the methane yield and the total and soluble chemical organic demand, total solids, and volatile solids removal. The results showed that the ultrasound pretreatment caused an increase of around 22.2% in CODt removal for an SRT of 7.5 d. Meanwhile, an SRT of 3 d resulted in a decrease of up to 92.4% in CODt removal. The performance in terms of biogas production and organic matter removal was significantly affected by the SRT reduction to 3 d, showing that the process is not viable in these conditions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Anatolian Environmental & Animal Science is the property of Bulent Verep and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study was conducted on 56 cats (49 males and 7 females) who presented with signs of feline lower urinary tract disease (FLUTD). Abdominal radiographs and ultrasounds, urinalysis, bacterial culture, and stone analysis were performed. Serum blood urea nitrogen (BUN) and creatinine were investigated. Urine sample analysis was investigated microscopically. The results indicated that the most common causes of lower urinary tract affections were urolithiasis (37.5%), followed by feline idiopathic cystitis (FIC) (33.9%), bacterial urinary tract infection (UTI) (14.2%), urethral plugs (10.7%) and neoplasia (3.5%). Urethral obstruction was (42.8%) more frequent in cats with urolithiasis, urethral plugs and FIC. Cats with FIC and urethral plugs were significantly younger than other diagnostic groups. Cats with urolithiasis and neoplasia had higher body weights than other FLUTD groups. Persian cats (39.5%) were the most affected breed. The mineral compositions in the analyzed uroliths were calcium oxalate (62.5%), struvite (50%) and ammonium urate (25%). FLUTD urine sediment crystalluria were triple phosphate struvite crystals (51.7%), calcium oxalate crystals (16.0%), and ammonium urate crystals (12.5%). FIC, urethral plugs and urolithiasis showed a significant increase in crystalluria and urethral obstruction. Urethral obstruction represented 42.8%, and it occurred frequently in cats with urolithiasis, urethral plugs and FIC. Post-renal azotemia with increased BUN and creatinine concentrations was detected in obstructive urolithiasis, urethral plugs and FIC. The identified bacterial cultures included Escherichia coli (37.5%), Staphylococcus aurous (37.5%) and Proteus species (25%). The results obtained from the study indicate that age, breed, sex and indoor confinement represent real challenges in developing lower urinary tract affections. [ABSTRACT FROM AUTHOR]

Bio-mediated soil improvement technologies leverage microbial enzymatic and metabolic processes to generate minerals, gases and biopolymers that can improve soil engineering behaviours with the potential to reduce detrimental environmental impacts when compared with conventional methods. Ureolytic biocementation is perhaps the most widely researched of these processes and relies on urea hydrolysis in the presence of calcium to initiate the precipitation of calcium carbonate minerals on soil particle surfaces and contacts, thereby improving soil behaviours. Although effective, urea hydrolysis generates aqueous ammonium by-products that may result in undesirable environmental and human health impacts, if left unaddressed. Recent studies have shown the potential of rinse solution injections to effectively remove generated ammonium following biocementation through both advective flow and the removal of sorbed ammonium from soil surfaces; however, critical gaps remain in our understanding of the effect of rinse solution composition and injection strategies on ammonium removal efficacy. In this study, 16 soil column experiments were performed to investigate the effect of rinse solution cation types, cation concentrations, applied injection sequences and biocementation treatment variations on the removal of ammonium from a biocemented poorly graded sand. All columns receiving cation-enriched rinse solutions achieved greater than 98% aqueous, 65% sorbed and 95% total ammonium removal after injecting 12 pore volumes, with no detectable impacts on cementation integrity. Cation-enriched solutions specifically enhanced sorbed ammonium removal and achieved sorbed ammonium concentrations up to 2 orders of magnitude less than those observed in columns rinsed with deionized water alone. Columns receiving K+-based rinse solutions and 12 daily 1-PV rinse injections also achieved greater total ammonium removal when compared with comparable columns receiving rinse solutions containing other cations and continuous 12-PV rinse injections. [ABSTRACT FROM AUTHOR]

In recent decades, extensive use of nitrogen fertilizers has drastically increased ammonium contamination in soil and groundwater. Ammonium contamination in soil is governed by the adsorption mechanism, which depends on the different types of soil through which the contaminant migrates. Understanding the adsorption mechanism of ammonium (NH4+) ions and the factors influencing them is critical for predicting and mitigating contamination. This study attempted to thoroughly investigate the effects of soil clay content on adsorption and, ultimately, the retardation of NH4+ ion movement in porous media. Ammonium ion transport was investigated using soil and batch experiments for single, mixed, and layered soil types with varying clay proportions. The experimental results were validated by numerically simulating NH4+ ion migration with HYDRUS 2D software (version 2.05.0270). Furthermore, the linear superposition relationship between the distribution coefficient (Kd) and mass of each individual soil layer was investigated and found to be appropriate for calculating an integrated Kd of NH4+ ions in layered soil. The attenuation of infiltration of NH4+ ions into the groundwater was found to be greatly dependent on clay content and the orientation of the soil. Hence, this study can be immensely useful in suggesting mitigation measures to control ammonium contamination in groundwater. [ABSTRACT FROM AUTHOR]

Ammonium removal from seepage water (representative stormwater) by ion exchange was investigated experimentally on laboratory and pilot scales. The results present the removal of ammonium from the worst-case scenario of stormwater, which is seepage water. Ammonium removal was efficiently accomplished with commercial resin CS16GC in proton and sodium forms. With the resin in H+ form, simultaneous removal of Na+, K+, Ca2+, and Mg2+ was achieved, whereas with the resin in Na+ form, other metals except Na+ were removed. Resin regeneration could be done efficiently with 2 mol/L HCl and 2 mol/L NaCl. Cyclic (7 cycles) ammonium removal runs were conducted with the CS16GC resin in Na+ form on both laboratory and pilot scale. Qualitatively, the results obtained from the cyclic runs done on laboratory and pilot scales were similar; however, some differences were observed because of slightly different feed compositions. In the pilot-scale run, 95-100% ammonium removal was obtained. The performance of the commercial resin was efficient compared with novel materials reported in the literature in an analysis method proposed by the authors. Ion exchange--based ammonium removal was shown to be an efficient method, and further investigation on the longterm stability of the process is warranted. [ABSTRACT FROM AUTHOR]

The general trend in biomining (i.e., bioleaching and biooxidation) is the use of media with high concentrations of the nutrients (nitrogen as ammonium, phosphorous as phosphate, and K), which are considered to be essential for microbial growth. The depletion of any of the nutrients would affect negatively the bioleaching (and biooxidation) capacity of the microorganisms, so the formulation of the different media ensures that there is a surplus of nutrients. However, some of these nutrients (e.g., phosphate, K) may be already present in the ore and are made available to the microorganisms when the ore is exposed to the low-pH media used during bioleaching. The effect of phosphate addition (109 mg/L) and depletion on the bioleaching of low-grade sulfidic ore alongside the determination of ammonium (i.e., 25 mg/L, 50 mg/L, 109 mg/L, 409 mg/L, and 874 g/L) requirements were studied. The results of the experiments presented showed that the addition of phosphate did not have any effect on the bioleaching of the low-grade sulfidic ore while the addition of ammonium was necessary to obtain higher redox potentials (>650 mV vs. Ag/AgCl) and higher metal (Co, Cu, Ni, and Zn) dissolutions. Temperature was the factor that shaped the microbial communities, at 30°C, the microbial community at the end of all the experiments was dominated by Acidithiobacillus sp. as well as at 42°C, except when nutrients were not added and Sulfobacillus sp. was the dominant microorganism. At 55°C, DNA recovery was unsuccessful, and at 60°C, the microbial communities were dominated by Sulfolobus sp. In conclusion, the amount of nutrients in bioleaching could be reduced significantly to achieve the redox potentials and metal dissolution desired in bioleaching without affecting the microbial communities and bioleaching efficiencies.