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Background Objective Animals Methods Results Conclusion and Clinical Importance Minimally invasive approaches are the standard for treatment of upper urinary tract uroliths in humans.To describe the medical dissolution of upper urinary tract uroliths in a series of dogs and report clinical outcomes.6 female dogs (9 kidneys).Retrospective case series. A review of medical records in dogs that underwent medical dissolution of upper urinary tract uroliths utilizing diet, administration of antibiotics, and double‐pigtail ureteral stent(s) placement, when indicated, was performed. Medical management was generally continued for 4 weeks beyond urolith dissolution. Information on biochemical, microbiological, imaging, and clinical outcomes before and after dissolution were recorded.Six dogs (9 kidneys) were included with bilateral (3) or unilateral (3) nephrolithiasis, ureterolithiasis, or a combination. A ureteral stent(s) was placed endoscopically in 5/6 dogs (6/9 kidneys) for obstructive ureterolithiasis (n = 5) or a nonobstructive massive nephrolith (n = 1). All dogs had a positive urine culture of Staphylococcus pseudintermedius with a median urine pH of 7.25 (range, 6.5‐8) and 4/5 had pyonephrosis. All dogs had initial evidence of urolith dissolution at a median of 1.1 months (range, 0.42‐5.9), with complete dissolution of ureteroliths at a median of 3.9 months (range, 1.5‐7.6), nephroliths at 5.3 months (range, 1.5‐7.6), and lower urinary tract uroliths at 0.87 months (range, 0.42‐5.9). Stents were removed in 3/6 once dissolution was documented. The median follow‐up time was 519 days (range, 177‐2492 days).Medical dissolution and decompression of upper urinary tract struvite uroliths should be considered a minimally invasive treatment for dogs before more invasive options. [ABSTRACT FROM AUTHOR]

The unique positioning of mangrove ecosystems between land and sea makes them vital in the nitrogen cycle. The role of nitrification in the nitrogen cycle is important to provide nitrogen compounds readily absorbed by mangrove plants. Nevertheless, the nitrification process and nitrifying bacteria in mangrove areas have yet to be comprehensively understood. The primary objective of this study is to provide comprehensive analysis of nitrifying bacteria in mangrove sediments by conducting a systematic review. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method is used as a guide to help report reviews systematically and has a flow chart to show the process of selecting relevant studies. Data collection was carried out by utilizing 6 databases and journal search engines including Scopus, PubMed, ResearchGate, Google Scholar, and Springer in order to achieve more comprehensive findings. This study employed the widely recognized and commonly used technique of defining the review's scope in a focused manner by first identifying the population, intervention, comparison, and outcome. This study identified 358 studies, and 31 studies were included in the review after screening. Based on the screening results, research on nitrifying bacteria in mangrove sediments is geographically limited to several countries such as Indonesia, Vietnam, Thailand, China, Mexico, the United States, India, and Saudi Arabia. This study vealed that there is a high level of diversity among nitrifying bacteria in mangrove sediment, with five distinct groups identified: ammonia oxidizing bacteria, nitrite oxidizing bacteria, anammox bacteria, and comammox bacteria, a recently identified group. In carrying out changes in nitrogen compounds, nitrifying bacteria use functional genes from different steps of the nitrification process, such as nitrogenase, ammonia monooxygenase subunit A, nitrite oxidoreductase alpha subunit, nitrate reductase alpha chain, nitrite reductase, nitric oxide reductase, nitrous oxide reductase, hydrazine synthase, hydrazine oxidoreductase and hydroxylamine oxidoreductase genes. Ammonia-oxidizing bacteria were the predominant group in general, but various nitrifying bacteria groups were distributed diversely across different mangrove environments. This study also indicated the vegetation type and the distribution of nitrifying bacteria in mangrove sediments. The depth of these sediments typically varies from 0 to 60 centimeters, with most samples taken at a depth of 0 to 20 centimeters. The type of vegetation at the sampling location is dominated by species of Kandelia candel, Avicennia marina, Kandelia obovata, and Rhizophora mangle. Limitations regarding research on nitrifying bacteria in mangrove sediments provide opportunities for in-depth study. This comprehensive review provides an in-depth overview of the variety and spread of nitrifying bacteria, highlighting their role in nitrogen cycling and emphasizing the potential for discovering new nitrifying bacteria in mangrove sediments. [ABSTRACT FROM AUTHOR]

We herein report two strategies for the quaternary ammonium hypoiodite‐mediated oxidative benzylic functionalization of p‐alkyl phenol derivatives. By using either dibenzoylperoxide or H2O2 in hexafluoroisopropanol in the presence of tetrabutyl ammonium iodide gives access to activated intermediates which can then be coupled with electron‐rich aromatic compounds. Overall, this sequential two‐step one‐pot procedure gives access to diversely decorated diarylmethane derivatives straightforwardly. Furthermore, the suitability of these products to undergo further oxidation reactions was successfully demonstrated. [ABSTRACT FROM AUTHOR]

Summary Plant root system is significantly influenced by high soil levels of ammonium nitrogen, leading to reduced root elongation and enhanced lateral root branching. In Arabidopsis, these processes have been reported to be mediated by phytohormones and their downstream signaling pathways, while the controlling mechanisms remain elusive in crops. Through a transcriptome analysis of roots subjected to high/low ammonium treatments, we identified a cytokinin oxidase/dehydrogenase encoding gene, CKX3, whose expression is induced by high ammonium. Knocking out CKX3 and its homologue CKX8 results in shorter seminal roots, fewer lateral roots, and reduced sensitivity to high ammonium. Endogenous cytokinin levels are elevated by high ammonium or in ckx3 mutants. Cytokinin application results in shorter seminal roots and fewer lateral roots in wild‐type, mimicking the root responses of ckx3 mutants to high ammonium. Furthermore, CKX3 is transcriptionally activated by type‐B RR25 and RR26, and ckx3 mutants have reduced auxin content and signaling in roots under low ammonium. This study identified RR25/26‐CKX3‐cytokinin as a signal module that mediates root responses to external ammonium by modulating of auxin signaling in the root meristem and lateral root primordium. This highlights the critical role of cytokinin metabolism in regulating rice root development in response to ammonium. [ABSTRACT FROM AUTHOR]

Synthetically challenging spirolactams were developed in good yields and regio-selectivity through a step-up oxidative dearomatization of easily accessible arenols tethered to esters in the presence of quaternary ammonium tribromide as an economic oxidant and amines. The reaction mechanism associated with this unprecedented dearomative lactamisation has been forecasted with a series of controlled experiments and DFT studies. [ABSTRACT FROM AUTHOR]

As a significant global source of vegetable oil, the oil palm's ability to withstand abiotic stresses, particularly drought, is crucial for sustainable agriculture. This is especially significant in tropical regions, where water scarcity is becoming more common. Nitrogen, a vital nutrient, plays an essential role in various physiological and biochemical processes in plants, directly influencing growth and stress tolerance. This study investigates the interaction between nitrogen sources (ammonium vs. nitrate) and drought stress in oil palm (Elaeis guineensis) seedlings, which is critical in enhancing productivity in this economically important crop. The experiment evaluated five commercial oil palm genotypes, which were supplied with nitrogen solutions (15 mM NH4+ or NO3−) for 46 days, followed by 30 days of progressive drought. The results showed that drought conditions universally reduced the biomass, with ammonium-fed plants exhibiting greater shoot biomass sensitivity than nitrate-fed plants. Drought also significantly decreased the chlorophyll a, PhiPS2, and root-reducing sugar levels—critical indicators of photosynthetic efficiency and overall plant health. The effects on the root architecture were complex, with ammonium nutrition differentially influencing the lateral root length under well-watered versus drought conditions, highlighting nitrogen forms' nuanced role in root development. Importantly, substantial genotypic variability was observed in most traits, affecting the responses to both the nitrogen source and drought stress. This variability suggests that certain genotypes may be better suited to cultivation in specific environmental conditions, particularly drought-prone areas. In conclusion, this study underscores the intricate interplay between nitrogen nutrition, genotypic variability, and drought tolerance in oil palm seedlings. These findings highlight the need to integrate these factors into agricultural management strategies to improve resilience and productivity in oil palm plantations. [ABSTRACT FROM AUTHOR]

Ceres is a partially differentiated dwarf planet located in the main asteroid belt. Consus crater (diameter ∼64 km) is one of the oldest impact features (∼450 Ma) on the Cerean surface that surprisingly still shows a large variety of color lithologies, including exposures of bright material, which are thought to be brine residues. Here, we present new results that help in understanding the structure and composition of the Cerean crust. These results were deduced by using newly processed Dawn Framing Camera (FC) color imagery and FC clear filter images combined with infrared spectral data of Dawn's Visible and Infrared Spectrometer (VIR). Consus exhibits a variety of color lithologies, which we describe in detail. Interestingly, we found three spectrally different types of bright material exposed by a large old crater on Consus' floor. One of these, the yellowish bright material (Nathues et al., 2023, https://www.hou.usra.edu/meetings/lpsc2023/pdf/1073.pdf) and its modification, shows spectral signatures consistent with ammonium‐enriched smectites. We hypothesize that the ammonium in these smectites stems from contact with ascending brines, originating from a low‐lying former brine ocean that has been enriched in ammonium during the differentiation and freezing process of the Cerean crust. This enrichment is mainly due to ammonium uptake by sheet silicates. If such an ammonium enrichment occurred over long‐time scales on a global scale, this process may explain the vast presence of ammonium on the Cerean surface. Therefore, an outer solar system origin of Ceres is possibly not needed to explain the global presence of ammonium. Plain Language Summary: Ceres is the largest object in the asteroid belt and surprisingly exhibits surface features formed by recent cryo‐volcanism, although evolution models predicted an inactive, completely frozen body. Cryo‐volcanism possibly stems from a brine layer at the crust‐mantle transition. The global presence of ammonium on the Cerean surface led to the conclusion of a potential outer solar system origin of Ceres. Here, we investigate the structure of its crust, by studying one of the older, but still mineralogical diverse, impact craters that excavated originally low‐lying materials. For our study, we are using data of the Dawn Framing Camera, spectral data of the Visible and Infrared Spectrometer as well as several geoscientific remote sensing methods. We describe "yellowish bright material" for the first time (Nathues et al., 2023, https://www.hou.usra.edu/meetings/lpsc2023/pdf/1073.pdf), that is spectrally unique in our color data and exhibits a strong absorption feature in the near‐infrared caused by ammonium. We hypothesize that the ammonium enrichment of this surface material is mainly a consequence of an ammonium exchange between rising brines and near‐surface phyllosilicates. If true, this would strengthen the case for the existence of a low‐lying ammonium‐rich brine layer, which in turn could weaken the hypothesis of an outer solar system origin for Ceres. Key Points: The old impact crater Consus still shows a large variety of color lithologiesThe yellow bright material lithology is ammonium‐enrichedWe hypothesize that this ammonium stems from ascending originally low‐lying brines [ABSTRACT FROM AUTHOR]

Hydrochemical signatures are often traced back to their original sources using data collected at catchment outlets. However, this approach introduces uncertainties, as signals may add up, cancel each other out, or be subject to transformation processes. Specifically rural point sources, such as communal wastewater treatment plants (WWTPs), are often overlooked and remain poorly understood in terms of their (local) impact, on water quality and quantity dynamics. We equipped a point source‐influenced headwater catchment with a comprehensive measurement setup, to directly trace the different hydrochemical signals. Statistical approaches were used to address c‐Q relationships and hydrochemical drivers for nutrient export upstream, downstream and within the WWTP during baseflow conditions. Groundwater infiltration into the old and leaky sewer system as well as rainwater collected via the combined sewer system were found to significantly alter processes within the WWTP, resulting in highly variable effluent nutrient concentrations. Ammonium introduced by the WWTP is rapidly transformed in the stream, leading to increasing nitrate concentrations further downstream. The combination of processes introduced by the WWTP overlap the dilution and (non‐significant) chemostatic patterns of the upstream nitrate‐discharge relationship, leading to enrichment patterns shortly after, and mainly diluting patterns 290 m downstream of the WWTP. Regarding maximum nutrient concentrations, dry periods during autumn were particularly critical, as the WWTP introduced high ammonium concentrations, which coincided with high nitrate concentrations from the catchment and a minimal dilution potential of the stream. Our study demonstrates the importance of incorporating all nutrient sources into catchment analyses, to facilitate successful management decisions. Plain Language Summary: Monitoring of point sources in rural areas, such as communal wastewater treatment plants, is often not very detailed. This makes it difficult to understand how they affect the water in streams. To fill that research gap, we installed a monitoring system in a rural catchment were a point source is located. We assessed water quality and quantity upstream, downstream and in the effluent. Leaky sewers and infiltrating groundwater probably influence the cleaning processes in the treatment plant, leading to varying nitrogen concentrations throughout the year. The mix of wastewater and upstream water creates a new chemical signal downstream of the wastewater treatment plant. This signal is additionally altered by ammonium, which is quickly transformed into nitrate as soon as it reaches the stream. In the fall, when stream water levels are low and can't dilute the effluent, the highest nitrogen concentration can be measured in the stream. Key Points: The point source alters the dynamics of the nitrate‐c‐Q relationship observed upstream of the WWTP, especially during low flow conditionsGroundwater infiltration into sewer system accounts for >60% of sewer water and can lead to variable water quality of the WWTP effluentHighest catchment NO3‐N concentrations and highest effluent NH4‐N concentrations coincide when stream dilution potential is minimal [ABSTRACT FROM AUTHOR]

The mechanism of the influence of impurity phosphorus on the vanadium precipitation process is not clear. In this regard, the effect of phosphorus on the precipitation of vanadium from vanadium solutions with variable concentrations was investigated. The results showed that with the increase of P concentration, vanadium precipitation efficiency and V2O5 purity decreased gradually, and the decreasing trend of vanadium precipitation efficiency was more obvious in low concentration vanadium solution. The mechanism of phosphorus effect on vanadium precipitation was analyzed by Raman spectroscopy. It was found that the phosphorus in the solution reacted with vanadium to form P-V heteropolyacids, leading to a decrease in the content of H2V10O284−, thus reducing the precipitation efficiency of vanadium. The V-P-H2O diagrams for vanadium solutions of different concentrations show that the lower the vanadium concentration, the more P-V heteropolyacids are formed, which leads to a lower H2V10O284− content and a lower vanadium precipitation efficiency. [ABSTRACT FROM AUTHOR]

Nutrient concentrations in many estuaries have increased over the past century due to increases in wastewater discharge and increased agricultural intensity, contributing to multiple environmental problems. Numerous biogeochemical and physical processes in estuaries influence nutrient concentrations during transport, resulting in complex spatial and temporal variability and challenges identifying predominant processes and their rates. Mechanistic models which require these rates to quantify biogeochemical processes become complex and difficult to calibrate as the number of processes and parameters grows, owing to the high dimensionality of the parameter space and the computational cost of simultaneously modeling the transport and transformations of constituents. We developed a modeling approach that decouples transport from transformations, enabling fast, data-driven exploration of the parameter space. The approach extracted information including water age, cumulative exposure to specific habitats, and mean water depth exposure from a hydrodynamic model. Using this information, a biogeochemical model was implemented to predict ammonium and nitrate concentrations in a Lagrangian frame. The model performed each simulation in milliseconds on a laptop computer, allowing the fitting of rate parameters for key transformations by optimization. The optimization used fixed station nitrate observations and the model was then validated against high-resolution mapping observations of ammonium and nitrate. The results suggest that the observed spatial and temporal variation can be largely represented with five transformation processes and their associated rates. Dissolved inorganic nitrogen (DIN) losses occurred only in shallow vegetated areas in the model, highlighting that biogeochemical processes in these areas should be included in DIN models. [ABSTRACT FROM AUTHOR]

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]

The dramatic decrease in atmospheric CO2 concentration during Oligocene was proposed as directly linked to C4 evolution. However, it remains unclear how the decreased CO2 concentration directly facilitate C4 evolution, besides its role as a selection pressure. We conducted a systematic transcriptomics and metabolomics analysis under short-term low CO2 condition and found that Arabidopsis grown under this condition showed 1) increased expression of most genes encoding C4-related enzymes and transporters; 2) increased expression of genes involved in photorespiration and pathways related to carbon skeleton generation for ammonium refixation; 3) increased expression of genes directly involved in ammonium refixation. Furthermore, we found that in vitro treatment of leaves with NH4 + induced a similar pattern of changes in C4 related genes and genes involved in ammonium refixation. These data support the view that Arabidopsis grown under short-term low CO2 conditions rewired its metabolism to supply carbon skeleton for ammonium recycling, during which process the expression of C4 genes were up-regulated as a result of a hitchhiking process. This study provides new insights into the adaptation of the C3 model plant Arabidopsis under low CO2 conditions and suggests that low CO2 can facilitate the evolution of C4 photosynthesis beyond the commonly assumed role of being a selection pressure. [ABSTRACT FROM AUTHOR]

The recovery of pure water and valuable substances from wastewater is a major challenge in the context of the circular economy, requiring advanced separation methods. However, actual membrane separation techniques such as forward osmosis are limited by membrane fouling and selectivity. Here, we synthesized composite membranes by crosslinking polyvinyl alcohol hydrogel, using both glutaraldehyde and borax as crosslinking agents, on top of cellulose ester membranes. We tested these composite membranes on model and real wastewater. Results show that the composite membranes retain ammonium effectively, maintain surface electroneutrality, and exhibit remarkable resistance to fouling by organic and biological contaminants. This is explained by the high hydrophilicity of the membrane surface after application of a hydrogel layer. [ABSTRACT FROM AUTHOR]

Here we review the 400-year history of hydroponic culture and describe a unique management approach that does not require leaching or discarding solution between harvests. Nutrients are maintained at a low and steady concentration by daily additions of a dilute solution that replaces the transpired water along with the nutrients that were removed in growth each day. A stable pH and a low steady-state concentration of ammonium are maintained through automated additions of a solution of nitric acid and ammonium nitrate. Ample solution volume (at least 20 cm deep) stabilizes nutrient concentrations, reduces root density, and improves uniformity. Gentle aeration at ≈100 mL·min-1·L-1 maintains dissolved oxygen near saturation and increases uniformity throughout the rhizosphere. These practices facilitate a uniform, closed, root zone with rigorous pH control that provides the micromolar nutrient concentrations of N and P that are representative of field soils. [ABSTRACT FROM AUTHOR]

In this study, the results of hydrochemical measurement aboard the RV Kavoshgar Khalij Fars in the Persian Gulf (PG) in September 2018, May, and November 2019 are discussed. Nitrate, nitrite, ammonium, phosphate, and silicate concentrations, salinity, temperature, dissolved oxygen, and pH in the water column of a 1000-km transect in the PG were studied to determine the present status of nutrient regimes of this region. Nitrate, phosphate, and silicate were more concentrated at the bottom layer and showed a maximum just below the thermocline in summer and autumn. Seasonal distribution of nutrient ratios (N:P, N:Si, Si:P) indicates P limitation in autumn, N limitation in spring, P limitation and poor Si in summer throughout the upper layer. The results of this study do not infer eutrophication in the upper layer of the PG waters in autumn and summer. [ABSTRACT FROM AUTHOR]

Nitrogen (N) losses from agriculture through leaching and volatilization have significant environmental and economic impacts. To find better options for reducing N losses, different N management approaches were compared to determine leaching losses of Nr (NH4+-N and NO3−-N) and ammonia (NH3) volatilization from wetland rice. The experiment comprised seven treatments, viz., zero N (control), recommended dose of N (RDN), 125% of RDN (RDN125), 75% of RDN (RDN75), cowdung 2 t ha−1 + supplemented N (CDSupN), biochar 2 t ha−1 + RDN (BRDN), and deep placement of urea super granules (USG). The recommended N rates of prilled urea were 186 kg ha−1 in the Boro (dry season) and 102 kg ha−1 in the Aman (wet season), while those for USG were 95 kg ha−1 in the Boro season and 75 kg ha−1 in the Aman season. The study was conducted in four consecutive seasons of Boro and Aman rice. Leaching losses of NH4+-N varied between 1.3 and 9.4 kg ha−1 in the Boro season and 0.9 and 5.9 kg ha−1 in the Aman season, while leaching of NO3−-N ranged from 1.4 to 11.8 kg ha−1 in Boro season and 0.7 to 4.4 kg ha−1 in Aman season. During the four consecutive rice growing seasons, N leaching and NH3 volatilization losses followed the order of RDN125 > RDN > RDN75 > CDSupN > BRDN > USG > control. Compared with the applied N, the N leaching losses were only 3% in the BRDN and 4–5% in the USG treatments which were almost half that of the RDN125 and RDN treatments. In proportion to the applied N, the N volatilization losses were only 8–9% in the BRDN and 5–6% in the USG treatments which were almost half as that in the RDN125 and RDN treatments. Losses by NH3 volatilization exceeded losses by leaching across all N treatments. Compared with the RDN treatment, grain yield increased by 15% in the BRDN and 8% in the USG treatments in the Boro season, while for the Aman season there was a 17% increase in the BRDN and 9% in the USG. Biochar with RDN and USG had the greatest potential to reduce N losses without loss of rice yields and can therefore be recommended as improved practices for rice-growing farmers. [ABSTRACT FROM AUTHOR]

The unique positioning of mangrove ecosystems between land and sea makes them vital in the nitrogen cycle. The role of nitrification in the nitrogen cycle is important to provide nitrogen compounds readily absorbed by mangrove plants. Nevertheless, the nitrification process and nitrifying bacteria in mangrove areas have yet to be comprehensively understood. The primary objective of this study is to provide comprehensive analysis of nitrifying bacteria in mangrove sediments by conducting a systematic review. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses method is used as a guide to help report reviews systematically and has a flow chart to show the process of selecting relevant studies. Data collection was carried out by utilizing 6 databases and journal search engines including Scopus, PubMed, ResearchGate, Google Scholar, and Springer in order to achieve more comprehensive findings. This study employed the widely recognized and commonly used technique of defining the review's scope in a focused manner by first identifying the population, intervention, comparison, and outcome. This study identified 358 studies, and 31 studies were included in the review after screening. Based on the screening results, research on nitrifying bacteria in mangrove sediments is geographically limited to several countries such as Indonesia, Vietnam, Thailand, China, Mexico, the United States, India, and Saudi Arabia. This study vealed that there is a high level of diversity among nitrifying bacteria in mangrove sediment, with five distinct groups identified: ammonia oxidizing bacteria, nitrite oxidizing bacteria, anammox bacteria, and comammox bacteria, a recently identified group. In carrying out changes in nitrogen compounds, nitrifying bacteria use functional genes from different steps of the nitrification process, such as nitrogenase, ammonia monooxygenase subunit A, nitrite oxidoreductase alpha subunit, nitrate reductase alpha chain, nitrite reductase, nitric oxide reductase, nitrous oxide reductase, hydrazine synthase, hydrazine oxidoreductase and hydroxylamine oxidoreductase genes. Ammonia-oxidizing bacteria were the predominant group in general, but various nitrifying bacteria groups were distributed diversely across different mangrove environments. This study also indicated the vegetation type and the distribution of nitrifying bacteria in mangrove sediments. The depth of these sediments typically varies from 0 to 60 centimeters, with most samples taken at a depth of 0 to 20 centimeters. The type of vegetation at the sampling location is dominated by species of Kandelia candel, Avicennia marina, Kandelia obovata, and Rhizophora mangle. Limitations regarding research on nitrifying bacteria in mangrove sediments provide opportunities for in-depth study. This comprehensive review provides an in-depth overview of the variety and spread of nitrifying bacteria, highlighting their role in nitrogen cycling and emphasizing the potential for discovering new nitrifying bacteria in mangrove sediments.

Granular activated carbon has been modified by ammonium persulfate as a new adsorbent for Cr(VI) adsorption from aqueous solutions. The adsorbent was characterized by nitrogen adsorption–desorption isotherm data and infrared spectroscopy. The impact of different factors, such as the initial pH level of the solution, time, temperature, ionic strength, and initial concentration of the Cr(VI) ion, on the adsorption efficiencies of the adsorbent has been studied by batch experiments. Kinetic studies and the adsorption thermodynamics of Cr(VI) with ammonium persulfate-modified activated carbon adsorbent were carefully studied. The results showed that the Cr(VI) adsorption follows a pseudo-second-order kinetic model and the adsorption reaction is endothermic and spontaneous. The adsorption isotherm was scrutinized, and the fitting results showed that the Langmuir model could well represent the adsorption process. The maximum adsorption capacity of Cr(VI) onto persulfate-modified activated carbon was 108.69 mg g−1. The research results showed that using persulfate-modified activated carbon adsorbent can greatly remove Cr(VI) from aqueous solutions. [ABSTRACT FROM AUTHOR]

Tubulysins are among the most recent antimitotic compounds to enter into antibody/peptide‐drug conjugate (ADC/PDC) development. Thus far, the design of the most promising tubulysin payloads relied on simplifying their structures, e. g. by using small tertiary amide N‐substituents (Me, Et, Pr) on the tubuvaline residue. Cumbersome solution‐phase approaches are typically used for both syntheses and functionalization with cleavable linkers. p‐Aminobenzyl quaternary ammonium (PABQ) linkers were a remarkable advancement for targeted delivery, but the procedures to incorporate them into tubulysins are only of moderate efficiency. Here we describe a novel all‐on‐resin strategy permitting a loss‐free resin linkage and an improved access to super potent tubulysin analogs showing close resemblance to the natural compounds. For the first time, a protocol enables the integration of on‐resin tubulysin derivatization with, e. g. a maleimido‐Val‐Cit‐PABQ linker, which is a notable progress for the payload‐PABQ‐linker technology. The strategy also allows tubulysin diversification of the internal amide N‐substituent, thus enabling to screen a tubulysin library for the discovery of new potent analogs. This work provides ADC/PDC developers with new tools for both rapid access to new derivatives and easier linker‐attachment and functionalization. [ABSTRACT FROM AUTHOR]

Enhancing the thermal safety of hydrophobic SiO 2 aerogels (SAs) is crucial for its practical thermal insulation applications. Here, we explore a facile method to enhance the thermal safety of hydrophobic SAs with the introduction of ammonium polyphosphate intercalated layered double hydroxide (APP-LDH). The obtained results show that as-produced APP-LDH/SA composites maintain excellent fundamental properties, including low density (0.14–0.16 g/cm3), high porosity (92.8–93.5 %), high specific surface area (680.0–762.6 m2/g), and low thermal conductivity (25.3–26.9 mW/m/K). Notably, APP-LDH effectively inhibits the thermal oxidation decomposition of SAs. In comparison to pristine SAs and those modified solely with LDH, the APP-LDH/SA composites exhibit significantly improved thermal stability. The gross calorific value of the APP-LDH/SA-20 % (i.e., containing 20 wt% APP-LDH) decreases by 13.9 % and 5.2 % compared with that of neat SAs and SAs modified solely with 20 wt% LDH, respectively. The improved thermal stability and reduced gross calorific value completely confirm the enhancement of the thermal safety of the APP-LDH/SA composites. This work provides a simple method to improve the thermal safety of hydrophobic SAs, which expands the thermal insulation application scenarios of SAs. [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]

The first example of a heteroditopic receptor capable of cooperative recognition and extraction of ammonium salt (NH4X) ion-pairs is described. Consisting of a bidentate 3,5-bis-tellurotriazole chalcogen bond donor binding cleft, the appendage of benzo-15-crown-5 (B15C5) substituents to the tellurium centres facilitates binding of the ammonium cation via a co-facial bis-B15C5 sandwich complex, which serves to switch on chalcogen bonding-mediated anion binding potency. Extensive quantitative ion-pair recognition 1H NMR titration studies in CD3CN/CDCl3 (1 : 1, v/v) solvent media reveal impressive ion-pair binding affinities towards a variety of ammonium halide, nitrate and thiocyanate salts, with the heteroditopic receptor displaying notable ammonium halide salt selectivity. The prodigious solution phase NH4X recognition also translates to efficient solid–liquid and liquid–liquid extraction capabilities. [ABSTRACT FROM AUTHOR]

Dissimilatory nitrate reduction to ammonium (DNRA) received more attention for its ability to recover ammonium. This study investigated the possibility of low-frequency infrared electromagnetic field (IR-EMF) to improve DNRA. The optimal IR-EMF intensity of 0.04 μT could effectively improve DNRA activity of nonwoven fabric membrane bioreactors. In the long-term operation, the average ammonium conversion efficiency was enhanced by 117.7% and 62.5% under 0.04 μT and 0.06 μT IR-EMF, respectively. The highest nrfA-gene abundance and potential DNRA rate were obtained under 0.04 μT IR-EMF exposure. Bacteroidetes fragilis, Shewanelle oneidensis MR-1, and Thauera sp. RT1901 were selected to investigate the dynamic response of nitrogen transformation and energy metabolism to IR-EMF. The transcriptome sequencing and RT-qPCR results suggested that IR-EMF could enhance both denitrification and DNRA process, mainly by improving ATP synthesis to boost metabolic activity. This study provided an efficient method for the nitrogen recovery via DNRA process by applying IR-EMF. [ABSTRACT FROM AUTHOR]

In this work, the flame retardant ISA-APP, obtained by modification of ammonium polyphosphate (APP) with isopropanolamine (ISA), was employed in epoxy resins (EP) in an attempt to enhance the fire resistance of EP. The findings indicate that, with an incorporation of 20 wt% ISA-APP in the EP, the limiting oxygen index (LOI) of EP/ISA-APP attains 33.5%, accompanied by a UL94 test V-0 rating. This performance surpasses the flame retardancy observed in EP/APP composites at equivalent content. The outcomes derived from the cone calorimeter test (CCT) demonstrate that EP/ISA-APP significantly suppresses the release of heat, generation of smoke, and emission of noxious gas during EP/ISA-APP combustion. The peak-heat release rate (pHRR) and total heat release (THR) of EP/ISA-APP are decreased by 74.4% and 63.6%, respectively, compared to pure EP. Further analysis of the char residues of EP/ISA-APP shows that the P-O-C structure generated during combustion effectively contributes to a high-quality char layer formation. This investigation presents a viable approach for enhancing flame retardant and economic benefits of APP and advancing the development of highly effective flame retardants. [ABSTRACT FROM AUTHOR]

Background: Cancer occurs in 83% of liver diseases. Other risk factors for liver cancer include viral hepatitis, alcohol consumption, industrial chemicals, and a number of toxins. Another major disease that occurs following liver damage is hepatic encephalopathy. This condition arises primarily due to increased blood ammonia levels. Carvacrol, with antioxidant properties, reduces oxidative stress on the liver. The aim of this study was to investigate the effect of carvacrol on the improvement of hepatic encephalopathy in rats. Methods: In this experimental study, 60 male Wistar rats were randomly divided into six groups of 10 each. Liver damage and induction of oxidative stress were caused in the rats by administering thioacetamide (100 mg/kg/day) intraperitoneally for three consecutive days. Carvacrol was administered by gavage at 25, 50, or 100 mg/kg/day after thioacetamide treatment. We investigated the biomarkers of liver damage in the blood, such as alanine transaminase, lactate dehydrogenase, total protein, and bilirubin. We also assessed the effect of oxidative stress, as the key inducer of hepatic encephalopathy, on the liver by measuring the lipid peroxidation, antioxidants, reactive oxygen species, glutathione reserves, and ammonium levels in the serum and brain. Results: Thioacetamide significantly increased the biochemical markers in the rat sera, reflecting ammonium release and the development of oxidative stress (P<0.05). Conversely, the various doses of carvacrol significantly reduced the levels of biomarkers that are indicative of liver damage (P<0.05). Conclusion: The study findings provided experimental evidence in favor of the therapeutic effects of carvacrol and against liver injury induced by thioacetamide, leading to encephalopathy. [ABSTRACT FROM AUTHOR]

The vibrational spectra of the natural ammonium sulfates tschermigite NH4Al(SO4)2(H2O)12, lonecreekite NH4Fe(SO4)2(H2O)12, ammoniovoltaite (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18, sabieite NH4Fe(SO4)2, ammonioalunite NH4Al3(SO4)2(OH)6, and ammoniojarosite NH4Fe3(SO4)2(OH)6 were studied to determine the behavior of ammonium in symmetry-inappropriate positions. Disorder of the ammonium cation in salt crystals caused by the need to adjust the tetrahedral cation to the symmetry of the position to preserve the crystal symmetry was revealed. If the symmetry group of the position was not a subgroup of the tetrahedral symmetry group, the NH4 tetrahedron was distorted by the subgroup Hʹ common for Td and H, where H is the symmetry group of the position. Then, a polyhedron corresponding to the symmetry of the position was constructed from N = |H|/|Hʹ| (|H| and |Hʹ| are the orders of these groups) distorted tetrahedra. The disordered ammonium cation had several orientations (N), the superposition of which formally gave a polyhedron corresponding to the local symmetry. The maximum common subgroups for the given salts were C3v and C3. Distortion of ammonium led to activation of ν1 and ν2 [NH4+ ] vibrations in the IR spectrum and splitting of ν3 and ν4 [NH4+ ]. However, the effect was barely noticeable for ammonium in a centrosymmetric position, as in ammonioalunite and ammoniojarosite. The ν4 [NH4+] band was noticeably split and ν1 and ν2 [NH4+ ] vibrations were clearly visible in spectra of the ammonium alums, ammoniovoltaite, and sabieite. [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]

Partial nitritation (PN) is a novel treatment for nitrogen removal using aerobic ammonium oxidation with reduced oxygen requirements compared to conventional nitrification. This study evaluated the performance of the PN process and the factors influencing nitrogen removal from landfill leachate. During the reactivation of biomass, the results showed 70% ammonium removal, but only 20% total nitrogen removal. Further analysis showed that low nitrite accumulation and high nitrate production promoted the growth of nitrite‐oxidizing bacteria (NOB). The ammonium removal activity after soaking the cultivated biomass in synthetic water and leachate was measured to be 0.57, 0.1, 0.17, and 0.25 g N•g VSS−1•d−1 for synthetic wastewater and leachate soaking for synthetic wastewater, 12 h, 3 days, and 7 days, respectively. The study found abundant ammonium‐oxidizing bacteria (AOB) and NOBs in biomass soaked in synthetic wastewater. However, soaking in leachate promoted AOB growth and inhibited NOB growth making leachate suitable for PN. Practitioner Points: The study found that with a longer leachate‐soaking period for biomass, ammonium removal activity increases, which in turn increases ammonium conversions during the PN process.Ammonium‐oxidizing bacteria (AOB) can acclimate to landfill leachate substrate and grow with a longer soaking period.Nitrite‐oxidizing bacteria (NOB) were inhibited by landfill leachate substrate, which is beneficial for nitrite accumulation.Anabolized DO can convert nitrite to nitrate rapidly, which results in higher nitrate accumulation compared to nitrite accumulation.Hence, the DO level has to be sufficiently low to prevent nitrite oxidation and nitrate accumulation. [ABSTRACT FROM AUTHOR]

Two-dimensional/three-dimensional hierarchical self-supporting potassium ammonium vanadate@MXene hybrid films exhibit excellent electrochemical performance. [Display omitted] Currently, aqueous zinc ion batteries (AZIBs) have grown to be a good choice for large-scale energy storage systems due to their high theoretical specific capacity, low redox potential, low cost, and non-toxicity of the aqueous electrolyte. However, it is still challenging to obtain high specific capacity and stability suitable cathodes. Herein, hierarchical self-supporting potassium ammonium vanadate@MXene (KNVO@MXene) hybrid films were prepared by vacuum filtration method. Due to the three-dimensional nanoflower structure of KNVO with dual ions intercalation, high conductivity of two-dimensional Ti 3 C 2 T x MXene, and the hierarchical self-supporting structure, the AZIB based on the KNVO@MXene hybrid film cathode possessed superior specific capacity (481 mAh/g at 0.3 A/g) and cycling stability (retaining 125 mAh/g after 1000 cycles at a high current density of 10 A/g). In addition, the storage mechanism was revealed by various ex-situ characterizations. Hence, a new viewpoint for the preparation of AZIB self-supporting cathode materials is presented. [ABSTRACT FROM AUTHOR]

Forests are the largest carbon sink in terrestrial ecosystems, and the impact of nitrogen (N) deposition on this carbon sink depends on the fate of external N inputs. However, the patterns and driving factors of N retention in different forest compartments remain elusive. In this study, we synthesized 408 observations from global forest 15N tracer experiments to reveal the variation and underlying mechanisms of 15N retention in plants and soils. The results showed that the average total ecosystem 15N retention in global forests was 63.04 ± 1.23%, with the soil pool being the main N sink (45.76 ± 1.29%). Plants absorbed 17.28 ± 0.83% of 15N, with more allocated to leaves (5.83 ± 0.63%) and roots (5.84 ± 0.44%). In subtropical and tropical forests, 15N was mainly absorbed by plants and mineral soils, while the organic soil layer in temperate forests retained more 15N. Additionally, forests retained more N15H4+$$ {}^{15}\mathrm{N}{\mathrm{H}}_4^{+} $$than N15O3−$$ {}^{15}\mathrm{N}{\mathrm{O}}_3^{-} $$, primarily due to the stronger capacity of the organic soil layer to retain N15H4+$$ {}^{15}\mathrm{N}{\mathrm{H}}_4^{+} $$. The mechanisms of 15N retention varied among ecosystem compartments, with total ecosystem 15N retention affected by N deposition. Plant 15N retention was influenced by vegetative and microbial nutrient demands, while soil 15N retention was regulated by climate factors and soil nutrient supply. Overall, this study emphasizes the importance of climate and nutrient supply and demand in regulating forest N retention and provides data to further explore the impacts of N deposition on forest carbon sequestration. [ABSTRACT FROM AUTHOR]

On the basis of previous work, this paper systematically investigates the influence parameters and leaching kinetics of the ammonia leaching process of molybdenum calcine obtained by microwave roasting. The conditions of the ammonia leaching process of calcined molybdenum were optimized by changing the parameters of ammonia concentration, solid–liquid ratio, and leaching temperature. The results show that, when the concentration of ammonia was 25%, the mass of calcined molybdenum and the volume of ammonia were 1/2 g/ml, the leaching temperature was 75°C, and the leaching time was 60 min, the leaching efficiency of molybdenum can reach 91.74%, and the content of ammonium molybdate in the leaching product was 97.23 wt.%. In the leaching process, MoO3 in the solid phase is dissolved by ammonia to form ammonium molybdate, which conforms to the shrinking core model. The activation energy of the reaction is 57.8 kJ/mol and the rate control step is determined by the mixed model of chemical reaction and product layer diffusion. The apparent rate equation is expressed as: 1 3 ln 1 - x + 1 - x - 1 3 - 1 = 14.97 ω ammonia 2.004 (L / S) - 2.44 e - 57800 RT t . [ABSTRACT FROM AUTHOR]

Objective: To estimate the ammonia volatilization rate, using a texture gradient with increasing doses of ammonium in alkaline soils. Design/Methodology/Approach: The experiment took place in the Análisis Químico de Suelos lab of the Soil Department of the Universidad Autónoma Chapingo. The incubations consisted of 25 g of soil from the former Texcoco lake, with 12.5% clay. The soil was air-dried and sieved with a no. 10 mesh. The soil was mixed with three different concentrations (17.5%, 22.5%, and 32.5%) of bentonite, in order to increase clay content. The mixtures were placed in plastic containers with airtight seals. Twelve-point five mL of an ammonium sulfate solution (with 150, 300, 450, 600, and 750 mg of nitrogen kg soil-1 ) was added. The ammonia was recovered in a container with a boric acid solution. Volumetry was used to quantify ammonium. A completely randomized design with two factors (clay content and ammonium dose) was used. Data were analyzed with a regression analysis, analysis of variance, and Tukey Multiple Comparison Test, using the SAS OnDemand for Academics software. Results: The ammonia volatilization has a linear trend, with the concentration of the applied nitrogen. The volatilization rate ranged from 0.02 to 0.03 mg of ammonium per milligram of the nitrogen applied per kg soil-1 . Significant statistical differences were recorded between the effect of the N dose and the clay content on the ammonia volatilization rate. Study Limitations/Implications: Clay content in the soil and ammonia volatilization rate can be used as an indicator to estimate ammonia losses and the ammonia adsorption capacity of the soil. Findings/Conclusions: Ammonia volatilization is independent from clay content and takes place immediately after its application. It has a linear trend regarding the ammonia dose applied. Ammonia volatilization rate decreases (asymptotic trend) as the clay content increases in the soil. [ABSTRACT FROM AUTHOR]

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Ammonia (NH3) from animal feeding operations (AFOs) is an important source of reactive nitrogen in the US, but despite its ramifications for air quality and ecosystem health, its near‐source evolution remains understudied. To this end, Phase I of the Transport and Transformation of Ammonia (TRANS2Am) field campaign was conducted in the northeastern Colorado Front Range in summer 2021 and characterized atmospheric composition downwind of AFOs during 10 research flights. Airborne measurements of NH3, nitric acid (HNO3), and a suite of water‐soluble aerosol species collected onboard the University of Wyoming King Air research aircraft present an opportunity to investigate the sensitivity of particulate matter (PM) formation to AFO emissions. We couple the observations with thermodynamic modeling to predict the seasonality of ammonium nitrate (NH4NO3) formation. We find that during TRANS2Am northeastern Colorado is consistently in the NH3‐rich and HNO3‐limited NH4NO3 formation regime. Further investigation using the Extended Aerosol Inorganics Model reveals that summertime temperatures (mean: 23°C) of northeastern Colorado, especially near the surface, inhibit NH4NO3 formation despite high NH3 concentrations (max: ≤114 ppbv). Finally, we model spring/autumn and winter conditions to explore the seasonality of NH4NO3 formation and find that cooler temperatures could support substantially more NH4NO3 formation. Whereas NH4NO3 only exceeds 1 μg m−3 ∼10% of the time in summer, modeled NH4NO3 would exceed 1 μg m−3 61% (88%) of the time in spring/autumn (winter), with a 10°C (20°C) temperature decrease relative to the campaign. Plain Language Summary: Animal feeding operations (AFO; i.e., feedlots for large‐scale meat/dairy production) emit large amounts of ammonia into the atmosphere. Gas‐phase ammonia can change into aerosol‐phase ammonium (i.e., gas‐aerosol partitioning) and contribute to particulate matter air pollution. In this study, we try to understand whether ammonia emitted from AFOs is forming aerosols, and if so, what mechanisms are governing the gas‐aerosol transfer between ammonia and ammonium. To do so, we flew a research aircraft downwind of several AFOs in northeastern Colorado in summer 2021 and measured a suite of gases and aerosols (and temperature and relative humidity). We measured high amounts of ammonia gas and low amounts of ammonium aerosols, so the observations alone only indicate that ammonia from AFOs likely is not a significant source of summertime PM2.5. We then put our observations into an aerosol thermodynamic model and learned that summertime northeastern Colorado is too hot and dry to favor aerosol formation despite high amounts of ammonia. We also make some approximations of spring/autumn and winter conditions in the model and learn that the cooler temperatures could potentially support substantial PM2.5 formation. This means that ammonia from AFOs could be a significant source of wintertime PM2.5 pollution in Northeastern Colorado. Key Points: Ammonium nitrate formation in summertime over northeastern Colorado is ammonia‐rich and nitrate‐limitedObservations and model analyses indicate that <300 m agl, ammonium nitrate is usually <1 μg m−3 and inhibited by warmer temperaturesCooler temperatures during spring/autumn and winter in northeastern Colorado are predicted to support substantial NH4NO3 formation [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]

The prepared NVOY electrode achieves high stability and excellent cycle performance for AZIBs by embedding polypyrrole in ammonium vanadate layers to remove excess ammonium ions, expand the interlayer spacing, and enhance electronic conductivity. [Display omitted] Ammonium vanadate with stable bi-layered structure and superior mass-specific capacity have emerged as competitive cathode materials for aqueous rechargeable zinc-ion batteries (AZIBs). Nevertheless, fragile N H...O bonds and too strong electrostatic interaction by virtue of excessive NH 4 + will lead to sluggish Zn2+ ion mobility, further largely affects the electro-chemical performance of ammonium vanadate in AZIBs. The present work incorporates polypyrrole (PPy) to partially replace NH 4 + in NH 4 V 4 O 10 (NVO), resulting in the significantly enlarged interlayers (from 10.1 to 11.9 Å), remarkable electronic conductivity, increased oxygen vacancies and reinforced layered structure. The partial removal of NH 4 + will alleviate the irreversible deammoniation to protect the laminate structures from collapse during ion insertion/extraction. The expanded interlayer spacing and the increased oxygen vacancies by the virtue of the introduction of polypyrrole improve the ionic diffusion, enabling exceptional rate performance of NH 4 V 4 O 10. As expected, the resulting polypyrrole intercalated ammonium vanadate (NVOY) presents a superior discharge capacity of 431.9 mAh g−1 at 0.5 A g−1 and remarkable cycling stability of 219.1 mAh g−1 at 20 A g−1 with 78 % capacity retention after 1500 cycles. The in-situ electrochemical impedance spectroscopy (EIS), in-situ X-ray diffraction (XRD), ex-situ X-ray photoelectron spectroscopy (XPS) and ex-situ high resolution transmission electron microscopy (HR-TEM) analysis investigate a highly reversible intercalation Zn-storage mechanism, and the enhanced the redox kinetics are related to the combined effect of interlayer regulation, high electronic conductivity and oxygen defect engineering by partial substitution NH 4 + of PPy incorporation. [ABSTRACT FROM AUTHOR]

Modern crops exhibit diverse sensitivities to ammonium as the primary nitrogen source, influenced by environmental factors such as external pH and nutrient availability. Despite its significance, there is currently no systematic classification of plant species based on their ammonium sensitivity. We conducted a meta-analysis of 50 plant species and present a new classification method based on the comparison of fresh biomass obtained under ammonium and nitrate nutrition. The classification uses the natural logarithm of the biomass ratio as the size effect indicator of ammonium sensitivity. This numerical parameter is associated with critical factors for nitrogen demand and form preference, such as Ellenberg indicators and the repertoire of nitrogen transporters for ammonium and nitrate uptake. Finally, a comparative analysis of the developmental and metabolic responses, including hormonal balance, is conducted in two species with divergent ammonium sensitivity values in the classification. Results indicate that nitrate has a key role in counteracting ammonium toxicity in species with a higher abundance of genes encoding NRT2-type proteins and fewer of those encoding the AMT2-type proteins. Additionally, the study demonstrates the reliability of the phytohormone balance and methylglyoxal content as indicators for anticipating ammonium toxicity. [ABSTRACT FROM AUTHOR]

Unlike aquaporins or potassium channels, ammonium transporters (Amts) uniquely discriminate ammonium from potassium and water. This feature has certainly contributed to their repurposing as ammonium receptors during evolution. Here, we describe the ammonium receptor Sd-Amt1, where an Amt module connects to a cytoplasmic diguanylate cyclase transducer module via an HAMP domain. Structures of the protein with and without bound ammonium were determined to 1.7-and 1.9-Ångstrom resolution, depicting the ON and OFF states of the receptor and confirming the presence of a binding site for two ammonium cations that is pivotal for signal perception and receptor activation. The transducer domain was disordered in the crystals, and an AlphaFold2 prediction suggests that the helices linking both domains are flexible. While the sensor domain retains the trimeric fold formed by all Amt family members, the HAMP domains interact as pairs and serve to dimerize the transducer domain upon activation. [ABSTRACT FROM AUTHOR]

Nitrate, the form of nitrogen often associated with kelp growth, is typically low in summer during periods of high macroalgal growth. More ephemeral, regenerated forms of nitrogen, such as ammonium and urea, are much less studied as sources of nitrogen for kelps, despite the relatively high concentrations of regenerated nitrogen found in the Southern California Bight, where kelps are common. To assess how nitrogen uptake by kelps varies by species and nitrogen form in southern California, USA, we measured uptake rates of nitrate, ammonium, and urea by Macrocystis pyrifera and Eisenia arborea individuals from four regions characterized by differences in nitrogen availability—Orange County, San Pedro, eastern Santa Catalina Island, and western Santa Catalina Island—during the summers of 2021 and 2022. Seawater samples collected at each location showed that overall nitrogen availability was low, but ammonium and urea were often more abundant than nitrate. We also quantified the internal %nitrogen of each kelp blade collected, which was positively associated with ambient environmental nitrogen concentrations at the time of collection. We observed that both kelp species readily took up nitrate, ammonium, and urea, with M. pyrifera taking up nitrate and ammonium more efficiently than E. arborea. Urea uptake efficiency for both species increased as internal percent nitrogen decreased. Our results indicate that lesser‐studied, more ephemeral forms of nitrogen can readily be taken up by these kelps, with possible upregulation of urea uptake as nitrogen availability declines. [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]

The relationships between the hydrochemical and structural characteristics of the macrozoobenthos community, including biotic indices is analyzed in the rivers of the Neman basin in the spring and summer periods. The list of hydrochemical characteristics included pH, dissolved oxygen concentration, the concentration of ions of ammonium and nitrate nitrogen, dissolved phosphorus, and heavy metals. A close correlation was found to exist between the structural characteristics of zoobenthos and water hydrochemical composition; it can be clearly seen in the summer period. The maximal values of the correlation coefficients were obtained for the relationship between the shares of EPT and oligosaprobic species in the total number of macrozoobenthos. The correlation between the number of macrozoobenthos species and the hydrochemical characteristics was found to be unreliable. The importance of the multimetric approach, taking into account both the hydrobiological and hydrochemical characteristics was emphasized. [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]

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. [ABSTRACT FROM AUTHOR]