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The objective was to verify the performance of spectral techniques as well as validation models in the prediction of nitrogen, total organic carbon, and humic fractions under different cultivation conditions. Chemical analyses for the determination of nitrate, total nitrogen, total organic carbon, and the chemical fractionation of soil organic matter were performed, as well as spectral analyses by Vis-NIR-SWIR and X-ray fluorescence. The results of the spectroscopy were processed using RStudio v. 4.1.3, and PLSR and support vector machine learning algorithms were applied to validate the models. The Vis-NIR-SWIR and XRF spectroscopic techniques showed high performance and are indicated for the prediction of nitrogen, total organic carbon, and humic fractions in Ferralsols of medium sandy texture. However, it is important to highlight that each technique has its own characteristic mechanism of action: Vis-NIR-SWIR detects the element based on harmonic tones, while XRF is based on the atomic number of the element or elemental association. The PLSR and SVM models showed excellent validation results, allowing them to fit the experimental data, emphasizing that they are different statistical methods. [ABSTRACT FROM AUTHOR]

Synthetic polymer surfaces provide an excellent opportunity for developing materials with inherent antimicrobial and/or biocidal activity, therefore representing an answer to the increasing demand for antimicrobial active medical devices. So far, biologists and material scientists have identified a few features of bacterial cells that can be strategically exploited to make polymers inherently antimicrobial. One of these is represented by the introduction of cationic charges that act by killing or deactivating bacteria by interaction with the negatively charged parts of their cell envelope (lipopolysaccharides, peptidoglycan, and membrane lipids). Among the possible cationic functionalities, the antimicrobial activity of polymers with quaternary ammonium centers (QACs) has been widely used for both soluble macromolecules and non-soluble materials. Unfortunately, most information is still unknown on the biological mechanism of action of QACs, a fundamental requirement for designing polymers with higher antimicrobial efficiency and possibly very low toxicity. This mini-review focuses on surfaces based on synthetic polymers with inherently antimicrobial activity due to QACs. It will discuss their synthesis, their antimicrobial activity, and studies carried out so far on their mechanism of action. [ABSTRACT FROM AUTHOR]

One of the key reasons for the success of invasive plants is the functional differences between invasive plants and native plants. However, atmospheric nitrogen deposition may disrupt the level of available nitrogen in soil and the functional differences between invasive plants and native plants, which may alter the colonization of invasive plants. Thus, there is a pressing necessity to examine the effects of atmospheric nitrogen deposition containing different nitrogen components on the functional differences between invasive plants and native plants. However, the progress made thus far in this field is not sufficiently detailed. This study aimed to elucidate the effects of artificially simulated nitrogen deposition containing different nitrogen components (i.e., nitrate, ammonium, urea, and mixed nitrogen) on the functional differences between the Asteraceae invasive plant Bidens pilosa L. and the Asteraceae native plant Pterocypsela laciniata (Houtt.) Shih. The study was conducted over a four-month period using a pot-competitive co-culture experiment. The growth performance of P. laciniata, in particular with regard to the sunlight capture capacity (55.12% lower), plant supporting capacity (45.92% lower), leaf photosynthetic area (51.24% lower), and plant growth competitiveness (79.92% lower), may be significantly inhibited under co-cultivation condition in comparison to monoculture condition. Bidens pilosa exhibited a more pronounced competitive advantage over P. laciniata, particularly in terms of the sunlight capture capacity (129.43% higher), leaf photosynthetic capacity (40.06% higher), and enzymatic defense capacity under stress to oxidative stress (956.44% higher). The application of artificially simulated nitrogen deposition was found to facilitate the growth performance of monocultural P. laciniata, particularly in terms of the sunlight capture capacity and leaf photosynthetic area. Bidens pilosa exhibited a more pronounced competitive advantage (the average value of the relative dominance index of B. pilosa is ≈ 0.8995) than P. laciniata under artificially simulated nitrogen deposition containing different nitrogen components, especially when treated with ammonium (the relative dominance index of B. pilosa is ≈ 0.9363) and mixed nitrogen (the relative dominance index of B. pilosa is ≈ 0.9328). Consequently, atmospheric nitrogen deposition, especially the increased relative proportion of ammonium in atmospheric nitrogen deposition, may facilitate the colonization of B. pilosa via a stronger competitive advantage. [ABSTRACT FROM AUTHOR]

The ammonia/ammonium (NH3/NH4+, AM) concentration in human erythrocytes (RBCs) is significantly higher than in plasma. Two main possible mechanisms for AM transport, including simple and facilitated diffusion, are described; however, the driving force for AM transport is not yet fully characterized. Since the erythroid ammonium channel RhAG forms a structural unit with anion exchanger 1 (eAE1) within the ankyrin core complex, we hypothesized the involvement of eAE1 in AM transport. To evaluate the functional interaction between eAE1 and RhAG, we used a unique feature of RBCs to swell and lyse in isotonic NH4+ buffer. The kinetics of cell swelling and lysis were analyzed by flow cytometry and an original laser diffraction method, adapted for accurate volume sensing. The eAE1 role was revealed according to (i) the changes in cell swelling and lysis kinetics, and (ii) changes in intracellular pH, triggered by eAE1 inhibition or the modulation of eAE1 main ligand concentrations (Cl− and HCO3−). Additionally, the AM import kinetics was analyzed enzymatically and colorimetrically. In NH4+ buffer, RBCs concentration-dependently swelled and lysed when [NH4+] exceeded 100 mM. Cell swelling and hemolysis were tightly regulated by chloride concentration. The complete substitution of chloride with glutamate prevented NH4+-induced cell swelling and hemolysis, and the restoration of [Cl−] dose-dependently amplified the rates of RBC swelling and lysis and the percentage of hemolyzed cells. Similarly, eAE1 inhibition impeded cell swelling and completely prevented hemolysis. Accordingly, eAE1 inhibition, or a lack of chloride anions in the buffer, significantly decreased NH4+ import. Our data indicate that the eAE1-mediated chloride gradient is required for AM transport. Taken together, our data reveal a new player in AM transport in RBCs. [ABSTRACT FROM AUTHOR]

This study explores the enhancement of aqueous zinc-ion batteries (AZIBs) using ammonium-enhanced vanadium oxide cathodes. Density Functional Theory (DFT) calculations reveal that NH4+ incorporation into V6O16 lattices significantly facilitates Zn2+ ion diffusion by reducing electrostatic interactions, acting as a structural lubricant. Subsequent experimental validation using (NH4)2V6O16 cathodes synthesized via a hydrothermal method corroborates the DFT findings, demonstrating remarkable electrochemical stability with a capacity retention of 90% after 2000 cycles at 5 A g−1. These results underscore the potential of NH4+ in improving the performance and longevity of AZIBs, providing a pathway for sustainable energy storage solutions. [ABSTRACT FROM AUTHOR]

Metallocene catalysts have attracted much attention from academia and industry for their excellent catalytic activity in the field of olefin polymerization. Cocatalysts play a key role in metallocene catalytic systems, which can not only affect the overall catalytic activity, but also have an obvious influence on the structure and properties of the polymer. Although methylaluminoxane (MAO) is currently the most widely used cocatalyst, its price increases the production cost of polyolefin materials. Ammonium tetrakis(pentafluorophenyl)borate has shown excellent performance in polymerization, being one of the best substitutes for the traditional cocatalyst MAO. Compared with the main catalyst, whose composition and structure are relatively complex, the research on cocatalyst is very limited. This review mainly introduces the research history, preparation methods, and application progress in polymerization of ammonium tetrakis(pentafluorophenyl)borate, deepening our understanding of the role of cocatalyst in polymerization, with the hope of inspiring brand-new thinking on improving and enhancing the overall performance of catalyst systems. [ABSTRACT FROM AUTHOR]

An important source of greenhouse gases in Brazil is the nitrous oxide (N2O) emission from pasture, and microorganisms play an important role in nitrogen transformations in the soil. This study aimed to evaluate N2O emission and NH3 volatilization from bovine excreta in pasture in an integrated crop–livestock system (ICL) in the Brazilian Cerrado. Three treatments (urine, dung and control) were performed in two pastures (Area 1—three-year pasture of Urochloa ruziziensis and Area 2—one-year pasture of Urochloa brizantha cv. Piatã), with two application times of the excreta (dry and rainy season), during two successive years of application. Compared to the control, the excreta deposition on ICL increased soil N2O and NH3 fluxes. In the dry season, N2O fluxes were associated with higher ammonium (NH4+) availability. In the rainy season, these fluxes were related to NO3− availability and water-filled pore space (WFPS). In both areas, NH3 volatilization was higher after urine than dung application, especially in the dry season. The highest N2O emission factors were obtained for urine (0.32%), the rainy season (0.36%), and older pasture (Area 1: 0.24%). All these values were below the mean IPCC default values (0.77%). These results indicate that N2O emissions in pasture should be evaluated in regional conditions. [ABSTRACT FROM AUTHOR]

Efficient adsorbents for excess bilirubin removal are extremely important for the treatment of hyperbilirubinemia. However, traditional adsorbents, such as activated carbons and ion-exchange resins, still suffer from dissatisfactory adsorption performance and poor blood compatibility. Herein, we adopted a rational design strategy guided by density functional theory (DFT) calculations to prepare blood-compatible quaternary ammonium group grafted electrospun polyacrylonitrile nanofiber adsorbents. The calculation analysis and adsorption experiments were used to investigate the structure–function relationship between group types and bilirubin adsorption, both indicating that quaternary ammonium groups with suitable configurations played a crucial role in bilirubin binding. The obtained nanofiber adsorbents showed the bilirubin removal efficiency above 90% even at a coexisting BSA concentration of 50 g L−1. The maximum adsorption capacities were 818.9 mg g−1 in free bilirubin solution and 163.7 mg g−1 in albumin bound bilirubin solution. The nanofiber adsorbents also showed considerable bilirubin removal in dynamic adsorption to reduce the bilirubin concentration to a normal level, which was better than commercial activated carbons. Our study demonstrates the high feasibility of a theory-driven design method for the development of grafted electrospun nanofibers, which have good potential as bilirubin adsorbents in hemoperfusion applications. [ABSTRACT FROM AUTHOR]

As a new type of green propellant, ammonium dinitramide (ADN)-based energetic propellants have wide application value and development potential in the field of space propulsion. This paper delves into the intricate impact of varying initial temperatures, pressures, and propellant component ratios on critical parameters, including temperature, combustion rate, and heat release, in the straight nozzle of an ADN-based propellant. The findings indicate that an elevation in both initial temperature and ADN ratio expedites the thermal decomposition rate of ADN, thereby elevating the average temperature in the nozzle. However, the elevation in initial temperature has a negative effect on the overall rise amplitude of average temperature. Furthermore, the initial pressure setting is crucial in determining whether the oxidation reaction of the fuel CH3OH occurs in ADN propellants. When the initial pressure is greater than 10 atm, CH3OH is completely consumed, and the final average temperature is about 2650 K, which increases by 558.89% compared with that at 1 atm. Our work aims to provide theoretical guidance and practical optimization strategies for enhancing propellant performance and optimizing thruster structure design. [ABSTRACT FROM AUTHOR]

Phaeocystis globosa is an important harmful algal species that is globally distributed. Previous studies have indicated that P. globosa preferentially uptake nitrate, but the underlying mechanism is still unclear. To further verify this preference and reveal the underlying mechanism, the assimilation rates of nitrate and ammonium by P. globosa at different concentrations was quantitatively studied by using a nitrogen stable isotope (15N) tracer technique, and the regulatory mechanism was determined from the physiological and biochemical responses. The findings revealed that the preferential assimilation of nitrate by P. globosa was influenced by the ambient ammonium concentration. When the ambient concentration of ammonium was less than approximately 3.5 μmol·L−1, the assimilation rates of nitrate form P. globosa were as high as 1.05 × 10−5 μmol·L−1·h−1·cell−1. Even though the nitrate assimilation in P. globosa was inhibited at ammonium concentrations greater than this threshold, nitrate assimilation could not be completely suppressed. The activity of NR and the expression of related genes in P. globosa were also affected by ammonium. In addition, 15N signals originally labeled nitrate accumulated in ammonium. This indicated that P. globosa was likely to reduce excess nitrate to ammonium and subsequently release it into the substrate, which might be an important energy dissipation mechanism for P. globosa. These results expand the classical understanding of the utilization of nitrogen nutrients by marine phytoplankton, and offer valuable resources for comprehending the mechanism of harmful algal blooms. [ABSTRACT FROM AUTHOR]

In recent years, in the field of bioanalysis, the use of saliva as a biological fluid for the determination of biomarkers has been proposed. Saliva analysis stands out for its simplicity and non-invasive sampling. This paper proposes a method for the dual determination of ammonium and hydrogen sulfur in saliva using two colorimetric chemosensors. The ammonia reacts with 1,2-Naftoquinone 4 sulphonic acid (NQS) entrapped in polydimethylsiloxane (PDMS) and the hydrogen sulfide with AgNPs retained in a nylon membrane. The color changed from orange to brown in the case of ammonia chemosensors and from yellow to brown in the H2S. The experimental conditions to be tested have been established. Both analytes have been determined from their gaseous form; these are ammonia from ammonium and hydrogen sulfur from hydrogen sulfur. Good figures of merit have been obtained by using both measuring strategies (reflectance diffuse and digitalized images). The acquired results show that both sensors can be used and provide good selectivity and sensitivity for the determination of these biomarkers in saliva. Both measurement strategies have provided satisfactory results for the real saliva samples (n = 15). Recoveries on spiked samples were between 70% and 100%. This methodology can lead to possible in situ diagnosis and monitoring of certain diseases and pathologies related with NH4+ and/or H2S, in a fast, simple, cheap and non-invasive way. [ABSTRACT FROM AUTHOR]

A large amount of ammonium salt leaching agent will remain in the leaching site of weathered crust elution-deposited rare earth ore (WREOs). The release of residual ammonium (RA) will seriously affect the water system ecology of the mining area, and it is urgent to control it. In this paper, column eluting was used to simulate the eluting process of RA in rare earth (RE) ore tailings, and the effects of calcium chloride concentration, eluting temperature, liquid-solid ratio, eluent pH and eluent flow rate on the eluting process of RA in rare earth ore tailings were discussed. It was found that calcium chloride could effectively elute the RA from ore tailings. Eluting agent pH almost had no effect on the eluting process of RA in the pH range of 4–6, and a greater impact on it at pH 8. The flow rate could effectively enhance the elution efficiency. The optimum conditions were calcium ion concentration of 0.1 mol/L, liquid-solid ratio of 2:1, pH 4–6, flow rate of 0.6 mL/min and elution at room temperature. At this time, the elution efficiency of RA was 91.85%. The eluting process of RA in ore tailings was controlled by the inner particle diffusing according to the kinetic analysis. The reaction order was 0.368, and the activation energy of the reaction is 12.450 kJ/mol. This will provide a theoretical basis and technical support for the efficient eluting process of residual ammonium in the leaching site of WREOs. [ABSTRACT FROM AUTHOR]

Cover crops in no-tillage systems may alter soil mineral N and influence the N fertilizer use efficiency (NFUE) of subsequent maize. The hypothesis of this work is that no-tillage systems with cover crops affect nitrate, ammonium and maize NFUE in the Brazilian Cerrado. The objective was to evaluate the cover crop mineralization effect on soil N mineral and maize NFUE in a no-tillage system, with and without N topdressing. The experiment was arranged in a randomized block split-plot design. The plots were represented by cover crops (Cajanus cajan, Crotalaria juncea, Raphanus sativus and Mucuna aterrima). The subplots consisted of the application (WN) or non-application (NN) of N topdressing to maize. The soil was sampled in six layers (up to 60 cm) at the end (April) and at the beginning of the rainy season (November). NH4+ was lower for all cover crops and WN and NN management in April. NO3− differed between seasons and cover crops in WN and NN. The lignin concentration and N uptake of M. aterrima were the highest compared to other species. The highest NFUE was on R. sativus, showing higher fertilizer dependency. In a no-tillage system with cover crops, the N topdressing fertilization needs to be improved, considering mineralization. [ABSTRACT FROM AUTHOR]

In this study, the response surface method is used to develop a model for analyzing and optimizing zinc leaching experiments. An investigation into the leaching kinetics of smithsonite in ammonium citrate solution is also conducted. A model of kinetics is studied in order to represent these effects. The experimental data show that an increase in the solution temperature, concentration, and stirring speed has a positive impact on the leaching rate, while an increase in the particle size has a negative impact on it. The optimal experimental conditions consist of a leaching temperature of 70 °C, ammonium citrate concentration of 5 mol/L, particle size of 38 µm, and rotational speed of 1000 rpm. Under these optimal conditions, the leaching rate of zinc from smithsonite is 83.51%. It is speculated that the kinetic model will change when the temperature is higher than 60 °C. When the temperature is lower than 60 °C, the leaching process is under the control of the shrinking core model of the surface chemical reactions. The calculated activation energy of the leaching reaction is equal to 42 kJ/mol. The model of the leaching process can be described by the following equation: 1 − 1 − x 1 / 3 = k 0 ⋅ (C) 0.6181 ⋅ r 0 − 0.5868 ⋅ S S 0.6901 exp ⁡ − 42 / R T ] t . This demonstrates that an ammonium citrate solution can be used in the leaching process of zinc in smithsonite as an effective and clean leaching agent. [ABSTRACT FROM AUTHOR]

Extensive industrial activities and anthropogenic agricultural practices have led to substantial ammonia release to the environment. Although croplands can act as ammonia sinks, reduced crop production under high concentrations of ammonium has been documented. Alpha-ketoglutarate (AKG) is a critical carbon source, displaying pleiotropic physiological functions. The objective of the present study is to disclose the potential of AKG to enhance ammonium assimilation in poplars. It showed that AKG application substantially boosted the height, biomass, and photosynthesis activity of poplars exposed to excessive ammonium. AKG also enhanced the activities of key enzymes involved in nitrogen assimilation: glutamine synthetase (GS) and glutamate synthase (GOGAT), elevating the content of amino acids, sucrose, and the tricarboxylic acid cycle (TCA) metabolites. Furthermore, AKG positively modulated key genes tied to glucose metabolism and ATP synthesis, while suppressing ATP-depleting genes. Correspondingly, both H+-ATPase activity and ATP content increased. These findings demonstrate that exogenously applying AKG improves poplar growth under a high level of ammonium treatment. AKG might function through sufficient carbon investment, which enhances the carbon–nitrogen balance and energy stability in poplars, promoting ammonium assimilation at high doses of ammonium. Our study provides novel insight into AKG's role in improving poplar growth in response to excess ammonia exposure. [ABSTRACT FROM AUTHOR]

The study of two-stage partial nitrification–anaerobic ammonium oxidation (PN/A) reactors, which are advantageous in engineering applications, still lacks research on process kinetics. Therefore, in this study, the start-up performance and process kinetics of a two-stage PN/A reactor were evaluated by controlling the reaction conditions, for which the two reactors were inoculated with sludge, incubated separately, and then operated in tandem. Increasing the ammonia load of the reactor during the 60 d stabilization period resulted in a nitrogen accumulation rate of 96.93% and a [NO2− − N]Eff/[NH4+ − N]Eff ratio of 1.33, which is close to the theoretical value of 1.32. Successful initiation of the A reactor was achieved after 55 d of operation by inoculating with anammox-activated sludge and granular activated carbon, and the PN and A reactors then successfully operated in combination for 20 d, with an average NH4+ − N efficiency of 99.04% and the NH4+ − N load of the A reactor showing an "S-shaped" curve. An analysis of the microbial growth kinetic models indicated that the removal of NH4+ − N could be successfully described by the logistic, modified logistic, modified Gompertz, and modified Boltzmann models. A strong association between the model and the dependent variable was observed. The process kinetic analysis showed that the removal of NH4+ − N from reactor A could be simulated under steady-state conditions, using the Grau second-order model. The parameters obtained from the model analysis are expected to help predict the denitrification performance of the reactor, facilitate operational management and control, and thus provide a promising research basis for the introduction of automated control systems. [ABSTRACT FROM AUTHOR]

Biochar (BC) and hydrochar (HC) have attracted considerable attention owing to their versatile characteristics and proven effectiveness in diverse technical fields. Solid BC is generated as a result of the dry carbonisation process of pyrolysis, in contrast to the slurry HC, which is produced during the hydrothermal carbonisation process. In this study, we evaluated the adsorption potential of two hydrochar samples (HCs) and three biochar samples (BCs) produced from sugar cane bagasse. The adsorption capacity of these samples was tested for ammonium, nitrate, and phosphate ions under various conditions. The BCs and HCs were subjected to characterisation using a CHNS/O analyser, the zeta potential, and Fourier transform infrared (FTIR). Elevating the pyrolysis temperature of the biochar resulted in changes in the fixed carbon and ash contents, while the volatile matter and H/C and O/C atomic ratios decreased. As the residence time increased, the H/C ratio and volatile matter content of the hydrochars (HCs) decreased. However, the fixed carbon content, ash content, and O/C and C/N ratios exhibited an increase. Thermodynamics, adsorption isotherms, and pH were also taken into consideration. The FTIR spectra analysis indicated that the carboxyl and ester functional groups present in both the BCs and HCs displayed reduced peak intensities subsequent to the adsorption of the three ions. While the adsorption was exothermic, we noticed that the adsorption capacity increased with temperature. The results indicate that sorption was homogenous across all binding sites, as evidenced by the optimal fit to the Langmuir isotherm. The research findings indicate that the adsorption capacity of various BC and HC adsorbents is significantly influenced by the surface area of the adsorbents in the case of nitrate and phosphate, but in the case of ammonia, adsorption is dictated by the functional polar groups present on the adsorbent surface. [ABSTRACT FROM AUTHOR]

Nitrogen and brassinosteroids (BRs) play a vital role in modulating the growth, development, and yield of rice. However, the influences of BRs on nitrogen assimilation and metabolism in rice are not fully understood. In this study, we analyzed the impact of BRs on nitrogen utilization in rice using the indica variety 'Zhongjiazao 17' and the japonica variety 'Nipponbare' in hydroponic conditions. The results showed that BR treatment could efficiently elevate nitrate and ammonium nitrogen accumulation in both shoots and roots. Furthermore, some genes involved in the uptake of nitrate and ammonium in roots were stimulated by BRs, though we noted subtle variances between the two rice cultivars. Moreover, BRs augmented the activity of nitrate reductase (NR) and glutamine synthetase (GS) in roots, along with NR in shoots. Interestingly, BRs also spiked the total free amino acid content in both the shoots and roots. Gene expression analysis uncovered a robust induction by BRs of NR genes and GS-related genes in the roots of both 'Nipponbare' and 'Zhongjiazao 17'. Collectively, our data suggest that BRs significantly enhance the accumulation of both nitrate and ammonium in rice and trigger a series of reactions related to nitrogen utilization. [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]

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]

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]

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]

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]

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]

Ammonium, as a major inorganic source of nitrogen (N) for sweet potato N utilization and growth, is specifically transported by ammonium transporters (AMTs). However, the activities of AMT family members in sweet potatoes have not been analyzed. In the present study, the sweet potato cultivar 'Pushu 32', which is planted in a large area in China, was used in field experiments at the Agricultural Base of Hainan University (20°06′ N, 110°33′ E) in 2021, and Sanya Nanfan Research Institute of Hainan University (18°30′ N, 109°60′ E) in 2022. Four N levels were tested: 0, 60, 120, and 180 kg ha−1. The results are as follows. Twelve IbAMT genes were identified in the sweet potato genome, which were classified into three distinct subgroups based on phylogeny; the same subgroup genes had similar properties and structures. IbAMT1.3 and IbAMT1.5 were mostly expressed in the storage roots under N deficiency. Compared with the NN and HN groups, IbAMT1.3 and IbAMT1.5 expressions, N content in storage roots, N uptake efficiency at the canopy closure, N fertilization contribution rates, number of storage roots per plant, storage root weight, and yield were all increased in the MN group. Furthermore, there was a significant positive correlation between the expressions of IbAMT1.3 and IbAMT1.5 with N content in the storage roots of sweet potato. In a word, IbAMT1.3 and IbAMT1.5 may regulate N utilization, affect the development of the storage root. and determine the yield of sweet potato. The results provide valuable insights into the AMT gene family's role in the use of N and effects on storage root development and yield in sweet potatoes. [ABSTRACT FROM AUTHOR]

Scientific evidence has increasingly supported the beneficial effects of probiotic-based food supplements on human intestinal health. This ex vivo study investigated the effects on the composition and metabolic activity of the intestinal microbiota of three probiotic-based food supplements, containing, respectively, (1) Bifidobacterium longum ES1, (2) Lactobacillus acidophilus NCFM®, and (3) a combination of L. acidophilus NCFM®, Lactobacillus paracasei Lpc-37™, Bifidobacterium lactis Bi-07™, and Bifidobacterium lactis Bl-04™. This study employed fecal samples from six healthy donors, inoculated in a Colon-on-a-plate® system. After 48 h of exposure or non-exposure to the food supplements, the effects were measured on the overall microbial fermentation (pH), changes in microbial metabolic activity through the production of short-chain and branched-chain fatty acids (SCFAs and BCFAs), ammonium, lactate, and microbial composition. The strongest effect on the fermentation process was observed for the combined formulation probiotics, characterized by the significant stimulation of butyrate production, a significant reduction in BCFAs and ammonium in all donors, and a significant stimulatory effect on bifidobacteria and lactobacilli growth. Our findings suggest that the combined formulation probiotics significantly impact the intestinal microbiome of the healthy individuals, showing changes in metabolic activity and microbial abundance as the health benefit endpoint. [ABSTRACT FROM AUTHOR]

Calcined soda production is one of the important parts of the industry. One of the main problems in the production of soda is the waste of raw materials. Disposing of some raw materials as waste not only causes economic damage but also has a negative impact on the environment. Absorption is the main process in the production of calcined soda. By finding the optimal consumption of the chemical components involved in absorption process, it will be possible to reduce the amount of raw materials released into the waste. In this work, initially, the kinetic model of the absorption process was found using the stoichiometric matrix method. Based on the stoichiometric matrix, the main components (NH3, CO2, NH4HCO3, NaCl) participating in the chemical reaction were identified. Using the found kinetic model, a computer model of the absorption process was simulated in the MATLAB program. Based on the simulated computer model, a diagram of changes in the concentration of components in the absorption process over time was obtained. The use of the considered mathematical model as part of the absorption process control system allows: (1) Reduce the loss of the amount of gases used in the absorption process; (2) Provide the required concentration of liquid saturated with ammonia; (3) Determine the required temperature regime along the entire length of the absorber. [ABSTRACT FROM AUTHOR]

Anaerobic digestate is proposed as an alternative to inorganic fertilisers, but a better understanding of how anaerobic digestates impact the soil and how plant growth is influenced is needed for wider acceptance. In this study, a series of pot experiments were conducted growing spring barley (Hordeum vulgare L.) in a range of soils with the application of digestate or synthetic fertiliser. Two application rates corresponding to total nitrogen at 120 and 480 kg ha−1 were used together with unfertilised soil as a control. Growth characteristics were measured as plant height, number of tillers, straw biomass, grain biomass and total biomass. Most growth characteristics (tillering, and straw and grain yield) increased with increasing application rates of nitrogen. An increase of 7–20% in plant height was observed with anaerobic digestate compared to synthetic fertilisers. However, results differed depending on the source of digestate and soil type. The nitrogen balance index (the ratio of the chlorophyll to polyphenolic compounds, which is linked to the nitrogen status of the crop) showed an increase of 40–50% for digestate applied at a nitrogen rate of 480 kg ha−1 compared to the control. By measuring nitrogen as ammonium, nitrate and nitrite in the different soils over 35 days, differential nitrogen release was also demonstrated, with soil water concentrations of ammonium decreasing rapidly after an early peak in all the treatments, and nitrate peaking after days 3–4. Results suggest that digestate may be used to replace synthetic fertilisers when applied in a range of soils. [ABSTRACT FROM AUTHOR]

Ammonium toxicity in macrophytes reduces growth and development due to a disrupted metabolism and high carbon requirements for internal ammonium detoxification. To provide more molecular support for ammonium detoxification in the above-ground and below-ground parts of Myriophyllum spicatum, we separated (using hermetic bags) the aqueous medium surrounding the below-ground from that surrounding the above-ground and explored the genes in these two regions. The results showed an upregulation of asparagine synthetase genes under high ammonium concentrations. Furthermore, the transcriptional down and/or upregulation of other genes involved in nitrogen metabolism, including glutamate dehydrogenase, ammonium transporter, and aspartate aminotransferase in above-ground and below-ground parts were crucial for ammonium homeostasis under high ammonium concentrations. The results suggest that, apart from the primary pathway and alternative pathway, the asparagine metabolic pathway plays a crucial role in ammonium detoxification in macrophytes. Therefore, the complex genetic regulatory network in M. spicatum contributes to its ammonium tolerance, and the above-ground part is the most important in ammonium detoxification. Nevertheless, there is a need to incorporate an open-field experimental setup for a conclusive picture of nitrogen dynamics, toxicity, and the molecular response of M. spicatum in the natural environment. [ABSTRACT FROM AUTHOR]

The transition from the linear economy paradigm to the circular economy in industrial wastewater treatment systems is on the global agenda. The search for new simple, eco-innovative, and low-cost processes for treating industrial wastewater, which can also be used by small and medium-sized industries, has been a constant challenge especially when environmental sustainability is considered. So, a new integrated industrial wastewater treatment system has been developed that includes the immediate one-step lime precipitation process (IOSLM) and atmospheric carbonation (AC), followed by constructed wetlands (CWs) or adsorption. The current review provides an overview of industrial wastewater treatment strategies for high- and low-biodegradable wastewater. A background on functionality, applicability, advantages and disadvantages, operating variables, removal mechanisms, main challenges, and recent advances are carried out for each process that makes up the IOSLM+AC+CW/adsorption integrated system. The prospects of the IOSLM+AC+CW/adsorption integrated system are also discussed. Not neglecting the improvements that still need to be made in the integrated treatment system as well as its application to various types of industrial wastewater, this review highlights that this treatment system is promising in industrial wastewater treatment and consequent by-product recovery. The IOSLM+AC integrated system showed that it can remove high amounts of organic matter, total suspended solids, oils and fats, phosphorus, and ammonium nitrogen from industrial effluents. On the other hand, constructed wetlands/adsorption can be alternatives for refining effluents still containing organic matter and nitrogen that were not possible to remove in the previous steps. [ABSTRACT FROM AUTHOR]

The consequences of using 25% whole or shelled sea urchin as an ingredient in anchovy sauce on its fermentation and development of its physicochemical properties after 20 days fermentation was studied. Two varieties of fish and sea urchin sauce were made with or without shell at 1:2:1 ratio (salt:fish:sea urchin) plus a control fish sauce at 1:3 ratio (salt:fish). All sauces were fermented at 40–50 °C for 20 days, where for the first 7 days the preparation remained in a static phase. During their fermentation, pH, salt concentration, aw, TVB-N, TMA, total nitrogen, formaldehyde nitrogen, amino nitrogen, and ammonium nitrogen, as well as aerobic mesophiles and lactic acid bacteria were monitored. The fermentation of the experimental sauces proved to follow an evolution rather similar to the control sauce. The whole and shelled sea urchins provided the necessary microbial and enzymatic load to trigger an adequate hydrolysis of the fish and the production of total nitrogen (16.0–17.6 g/L), formaldehyde nitrogen (15.1–16.0 g/L), and amino nitrogen (0.7–0.8 g/L) of the same order as the control sauce, despite the lower fish content. According to TMA (9.2–13.1 mg N/100 g), VBT (40.0–47.2 mg N/100 g) contents, and pH levels (5.41–5.46), no deviation of the fermentation process was observed under the experimental conditions (salt content, temperature, and agitation after the static phase). Quantitative descriptive analysis (QDA) sensory revealed that the use of sea urchin results in high quality products characterized by their aromas of crustaceans and mollusks. The present study investigates the potential use of shelled and even whole sea urchin as an ingredient for the preparation of high quality fish sauces. [ABSTRACT FROM AUTHOR]

To evaluate the effects of application of biochar and straw return for consecutive years on N2O emissions and crop yields in North China, a three-year field experiment of applying biochar and straw following a ten-year application was conducted in a wheat–maize rotation system. Four treatments were set up, including F (NPK fertilizer only); FB (NPK fertilizer + 9.0 t·ha−1 biochar); FS (NPK fertilizer + straw); and FSB ((NPK fertilizer + 9.0 t·ha−1 biochar combined with straw). The results showed that compared with the F treatment, the FB treatment significantly reduced soil N2O emissions by 20.2%, while the FS and FSB treatments increased it by 23.7% and 41.4%, respectively. The FB treatment reduced soil N2O emissions by 15.1% in the wheat season and 23.2% in the maize season, respectively. The FS and FSB treatments increased the N2O emissions by 20.7% and 36.7% in the wheat season, respectively, and by 25.5% and 44.2% in the maize season, respectively. In the wheat season, the soil water content (SWC), NO3−-N content and pH were the main influencing factors of the soil N2O emissions. In the maize season, SWC and NO3−-N content were the main influencing factors. In addition, the FB, FS and FSB treatments increased the crop yield by 4.99%, 8.40% and 10.25% compared with the F treatment, respectively. In conclusion, consecutive application of biochar can significantly reduce N2O emissions and improve crop yield. Although FS and FSB treatments can also improve the crop yield, they are not beneficial to suppressing N2O emissions. Therefore, the successive application of biochar is an effective measure to reduce N2O emissions and maintain crop yield. [ABSTRACT FROM AUTHOR]

Wellbore instability caused by the hydration of shale formations during drilling is a major problem in drilling engineering. In this paper, the shale inhibition performance of polyhydroxy-alkanolamine was evaluated using an anti-swelling test, linear swelling test, wash-durable test and montmorillonite hydration and dispersion experiment. Additionally, the shale inhibition mechanism of polyhydroxy-alkanolamine was studied via Fourier transform infrared spectroscopy (FTIR), particle size, zeta potential, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results show that the use of polyhydroxy-alkanolamine (EGP-2) could result in a relatively lower linear swelling rate of montmorillonite, and the linear swelling rate of 0.3% EGP-2 is 26.98%, which is stronger than that of 4% KCl. The anti-swelling rate of 0.3% EGP-2 is 43.54%, and the shrinkage–swelling rate of 0.3% EGP-2 is 34.62%. The study on the inhibition mechanism revealed that EGP-2 can permeate and adsorb on the surface of montmorillonite. The rolling recovery rate of easily hydrated shale was as high as 79.36%, which greatly reduces the dispersion ability of water to easily hydrated shale. The results of this study can be used to maintain the stability of a wellbore, which is conducive to related research. [ABSTRACT FROM AUTHOR]

Though fly ash from the incineration of municipal solid waste (MSW-FA) is considered hazardous waste, its huge and increasing volumes and potential value due to high concentrations of salts and heavy metals such as copper and zinc have attracted commercial interest in mining it for resources. The associated treatments used for extracting these resources may make it economically feasible to extract other constituents from the residuals, adding another potential pathway towards a zero-waste society. This review assesses the feasibility of using zeolites, synthesized from precursors extracted from MSW-FA, as sorbents for the recovery of nutrients (ammonium, nitrate, and phosphate) and heavy metals. It is possible to tailor the properties of the zeolites; however, the large variability in reported adsorption capacities and specificities, as well as the inherent heterogenic nature and variable composition and concentrations of most nutrient- or heavy metal-rich waste streams, make such tailoring challenging. A remaining important issue is the transfer of unwanted micropollutants from the MSW-FA or waste stream to the final products and the loss of surfactants from surfactant-modified zeolites during adsorption and/or desorption of nitrate and/or phosphate. Nonetheless, the recovery process is benefited by high concentrations of the target compounds and low concentrations of competing ions. [ABSTRACT FROM AUTHOR]

Studies on the impact of colonic fermentation of plant sterol (PS)-enriched foods using dynamic in vitro models are limited. This study aimed to evaluate the effect of a 72-h dynamic in vitro digestion-colonic fermentation (using the simgi® system) of PS-enriched rye bread on colonic microbial population and short-chain fatty acid (SCFA) and ammonium production. In all colon compartments (ascending colon (AC), transverse colon (TC), and descending colon (DC)) (72 vs. 0 h), a reduction in ammonium concentration (5.7- to 9.4-fold) and an increase in Staphylococcus spp. (1.4- to 2.1-fold), Lactobacillus spp. (1.5-fold), Bifidobacterium spp. (1.3- to 1.5-fold), and Enterococcus spp. (1.4- to 1.6-fold) were observed. In AC and TC, total SCFA decreased (4- and 1.3-fold, respectively), whereas it increased 1.4-fold in DC due to an increase in butyrate content from 4 to 45 mM. These results suggest that PS-enriched rye bread favors the growth of beneficial microbial species and the production of butyrate, a fuel source for enterocytes, thus promoting health benefits. [ABSTRACT FROM AUTHOR]

Optimal regulation of NH SB 4 sb SP + sp uptake from the environment plays a pivotal role in minimizing intracellular NH SB 4 sb SP + sp concentrations, thereby alleviating potential NH SB 4 sb SP + sp toxicity. Ammonium (NH SB 4 sb SP + sp ) and nitrate (NO SB 3 sb SP - sp ) are two major inorganic nitrogen (N) forms for plants. Therefore, it is important to study the molecular mechanisms of plant responses to NH SB 4 sb SP + sp nutrient stress, and to coordinate NH SB 4 sb SP + sp uptake and mitigate NH SB 4 sb SP + sp toxicity. Beyond the rhizosphere, futile NH SB 4 sb SP + sp efflux, triggered by NH SB 4 sb SP + sp absorption, is also a predominant factor contributing to NH SB 4 sb SP + sp toxicity [[10]]. [Extracted from the article]

The thermal decomposition of an ammonium dinitramide-based energetic compound was conducted for the first time using a dispersive inductively coupled plasma mass spectrometer, DTA-TG analysis, and pyrolysis at a constant temperature. A liquid droplet was injected over synthesized CuO catalytic particles deposited on lanthanum oxide-doped alumina. The thermal behavior of the ADN liquid monopropellant revealed that decomposition in the presence of catalytic particles occurs in two distinct steps, with the majority of ejected gases being detected in real-time analysis using the DIP-MS technique. At a temperature of 280 °C, pyrolysis confirmed the catalytic decomposition behavior of ADN, which occurred in two distinct steps. [ABSTRACT FROM AUTHOR]

Aerobic denitrifier Alcaligenes faecalis No. 4 removes ammonium-nitrogen to nitrogen gas via denitrification in a single aerobic condition. In our previous studies, factors such as ammonium removal rate, denitrification ratio, and cell growth were tested in various conditions. The removal pathway from ammonium to nitrogen gas still needs to be determined in detail. To clarify this pathway of Alcaligenes faecalis No. 4, we in this study investigated the effects of several factors on ammonium removal, such as foam-recycle, initial pH, initial ammonium concentration, and airflow rate. Denitrification ratio was improved by up to 23% through foam-recycle. The improvement of the denitrification ratio was resulted by the higher enzyme activity of hydroxylamine oxidoreductase (HAO) in the produced foam, which was about 28 times higher than that in the culture broth (i.e., without foam-recycle). The stripped ammonia was significantly high (above pH 9). The initial ammonium concentration and airflow rate also influenced the denitrification ratio. [ABSTRACT FROM AUTHOR]

Solar irradiation in aquatic systems can induce the conversion of substances from the solid to the dissolved phase (photodissolution). Yet, the photochemical release of dissolved organic nitrogen (DON) from internal particles in lakes remains largely unknown. In this study, suspensions of algal detritus and sediment particles from a shallow eutrophic lake were exposed to simulated solar irradiation, and the release and compositional changes of dissolved organic matter were explored by measuring their UV–Visible absorption spectroscopy and ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The photochemical release of inorganic nitrogen during the incubations was also investigated. Results showed that light irradiation induced stronger dissolved organic carbon and DON production in the algal detritus suspensions, with release rates of 1.17 mg C L−1 h−1 and 0.14 mg N L−1 h−1, respectively, at an algal detritus concentration of 0.1 dry g L−1. Light irradiation also induced compositional changes of DON in both algal and sediment suspensions. A larger number of DON molecules with lower molecular weight were continuously released in the algal suspensions, e.g., the total number of DON formulas increased from 1349 to 4135 during an 8 h irradiation. In contrast, upon irradiation of sediment suspensions, DON showed decreased molecular diversity and increased aromaticity. The photochemical release of ammonium (photoammonification) was also higher in the algal suspensions with a rate of 0.015 mg N L−1 h−1, which may contribute to the eutrophication of the lake. This study provides new molecular insights into the photochemical release of DON from typical internal particles in eutrophic lakes. [ABSTRACT FROM AUTHOR]

Root systems of most land plants are colonised by arbuscular mycorrhiza fungi. The symbiosis supports nutrient acquisition strategies predominantly associated with plant access to inorganic phosphate. The nutrient acquisition is enhanced through an extensive network of external fungal hyphae that extends out into the soil, together with the development of fungal structures forming specialised interfaces with root cortical cells. Orthologs of the bHLHm1;1 transcription factor, previously described in soybean nodules (GmbHLHm1) and linked to the ammonium facilitator protein GmAMF1;3, have been identified in Medicago (Medicago truncatula) roots colonised by AM fungi. Expression studies indicate that transcripts of both genes are also present in arbuscular containing root cortical cells and that the MtbHLHm1;1 shows affinity to the promoter of MtAMF1;3. Both genes are induced by AM colonisation. Loss of Mtbhlhm1;1 expression disrupts AM arbuscule abundance and the expression of the ammonium transporter MtAMF1;3. Disruption of Mtamf1;3 expression reduces both AM colonisation and arbuscule development. The respective activities of MtbHLHm1;1 and MtAMF1;3 highlight the conservation of putative ammonium regulators supporting both the rhizobial and AM fungal symbiosis in legumes. [ABSTRACT FROM AUTHOR]

Featured Application: The obtained research results can be used to support the removal of ammonium nitrogen from wastewater in a microalgae culture. Sewage sludge containing natural clinoptilolite and microalgae formed after the assimilation of ammonium nitrogen can be further used, e.g., for the reuse of alginate and wastewater. This new method brings benefits to the environment, the economy, and society. This work focused on the potential of simultaneously removing ammonium nitrogen from industrial wastewater using immobilized microalgae and powdered zeolite. Experiments were performed with different species and doses of microalgae embedded in spherical hydrogels in semicontinuous conditions. Ammonium nitrogen uptake by microalgae promoted the slow release of previously adsorbed ammonium nitrogen from zeolite that was then also absorbed by microalgae. Results showed that immobilized microalgae can reach a removal efficiency of up to 60% (C. vulgaris) and 42% (S. armatus). A higher removal efficiency was obtained for zeolites and immobilized C. vulgaris or S. armatus up to 86% and 79%, respectively. Moreover, a higher maximum sorption capacity for C. vulgaris (13.8 mg/g) was achieved than for S. armatus (5.5 mg/g). The recycling of spent hydrogel, zeolite, and wastewater is possible. Such an approach represents a circular bioeconomy loop. [ABSTRACT FROM AUTHOR]

Surfactants are amphiphilic molecules and one of the most versatile products of the chemical industry. They can be absorbed at the air–water interface and can align themselves so that the hydrophobic part is in the air while the hydrophilic part is in water. This alignment lowers the surface or interfacial tension. Gemini surfactants are a modern variety of surfactants with unique properties and a very wide range of potential applications. Hexamethylene-1,6-bis(N-dodecyl-N,N-dimethylammonium bromide) is one such representative compound that is a better alternative to a single analogue. It shows excellent surface, antimicrobial, and anticorrosion properties. With a highly efficient synthetic method and a good ecological profile, it is a potential candidate for numerous applications, including biomedical applications. [ABSTRACT FROM AUTHOR]

This study aimed to improve the performance of a wastewater treatment plant (WWTP) simulated with Benchmark Model No. 2 (BSM2). To achieve this objective, three control strategies were implemented and tested. The first control strategy aimed to maintain the concentration of nitrate and nitrite nitrogen (SNO) by controlling the external carbon flowrate (strategy A1), and the second control strategy aimed to maintain the ammonia and ammonium nitrogen (SNH) at a desired level with the use of a cascade controller (strategy A2). The third strategy was applied to control the total suspended solids (TSS) (strategy A3). Combinations of these strategies were considered (B1, B2, and B3 strategies), as well as the use of all three together (strategy C1). The control strategies presented in this paper were compared to the default control strategy of BSM2 to validate and identify the one that provided the best performance. The results revealed that the B1 strategy was the most environmentally friendly, while C1 obtained the highest overall performance. Several Monte Carlo simulations were performed for the validated control strategies, to identify the optimal setpoint values. For the C1 strategy, a second method of optimization regarding polynomial interpolation was considered. The applied optimization methods provided the optimal reference values for the PI (proportional integral) controllers. [ABSTRACT FROM AUTHOR]

High temperatures exacerbate the ammonia inhibition of anaerobic digestion coupled with methanogenesis. The inhibition of methane production by ammonia has been observed in other studies. However, the underlying mechanism is not well understood and requires further investigation. This study explored the effect of ammonia stress on archaeal 16S rRNA transcripts in thermophilic anaerobic digester sludge. Different ammonium concentrations were checked for their influence on the methanogenic rate and hydrogen accumulation. Quantitative PCR was used to compare the changes in total archaeal 16S rRNA expression. A Monte Carlo permutation test within redundancy analysis (RDA) was adopted for exploring the relationship between environmental variables and archaeal 16S rRNA and their transcripts. The results showed that with the increase in ammonium concentration, the methanogenic rate decreased and hydrogen accumulation occurred. The total archaeal 16S rRNA genes and transcripts copy numbers decreased significantly in treatments with higher ammonium concentrations (7 and 10 g NH4+-N/L), but did not change much at lower ammonia concentrations (3 g NH4+-N/L) compared with the 0 g NH4+-N/L treatment. The RDA analysis further revealed that most environmental variables, including ammonia and methane, except for formate, were significantly correlated with the community structure activity of archaeal 16S rRNA transcripts rather than the community structure of their genes. The composition of archaeal 16S rRNA transcripts showed that the hydrogenotrophic methanogen Methanothermobacter dominated the methanogenic community activity in all incubations. It exhibited sensitivity to ammonia stress and should be responsible for the methanogenic inhibition under thermophilic conditions. Our findings suggested that archaeal 16S rRNA transcripts, rather than 16S rRNA genes, are key indicators of ammonia stress and methanogenic activity. [ABSTRACT FROM AUTHOR]

Ammonium (NH4+) is an essential nitrogen source for plants, but excessive exposure can trigger stress responses that vary among and within different plant species. This study investigated the phenotypic variations in response to ammonium nutrition in five oil palm genotypes seedlings. Nitrate nutrition was used as a reference for a non-stressful condition, and three different nitrogen concentrations (5, 10, and 15 mM) were examined. Control groups without external nitrogen application were included for each genotype. Several parameters were analyzed, including plant growth, root length, gas exchange, fluorescence, chlorophyll, reducing sugars, amino acids, proteins, and nitrogen uptake. The results revealed a significant genotype effect, particularly between the interspecific OxG hybrid and the Elaeis guinensis genotypes. Ammonium nutrition increased shoot growth in all genotypes compared to nitrate nutrition. Additionally, there was a trend towards increased primary root length, amino acids, proteins, and nitrogen uptake under ammonium supply. These findings are promising, particularly considering the recommendation to use ammonium with inhibitors for environmental sustainability. [ABSTRACT FROM AUTHOR]