Key factors affecting NH3-N in the Huaihe River Basin due to human activities.

Human activity factors have a significant impact on changes in ammonia nitrogen (NH3-N) content in rivers. Existing research mainly focuses on human activity factors as type factors, and lacks research on the key factors affecting river NH3-N among human activity factors. Therefore, this paper aims to study the key factors affecting human activities on NH3-N in the Huaihe River through various statistical analysis methods. The study found that changes in NH3-N content in the Huaihe River are mainly affected by land use patterns in the basin. There are two different ways in which land use affects NH3-N in rivers: direct effects and indirect effects. We also studied the main pathways through which changes in key factors in human activities affect NH3-N in the Huaihe River by constructing a structural equation model. The results showed that crop sowing area and afforestation area have a significant direct effect on NH3-N in the Huaihe River. In addition, crop sowing area and afforestation area can also affect river NH3-N by regulating the amount of nitrogen fertilizer and human excrement. This study is of great significance for understanding how human activities regulate NH3-N content in rivers.

Metabolic phenotyping reveals an emerging role of ammonia abnormality in Alzheimer's disease.

The metabolic implications in Alzheimer's disease (AD) remain poorly understood. Here, we conducted a metabolomics study on a moderately aging Chinese Han cohort (n = 1397; mean age 66 years). Conjugated bile acids, branch-chain amino acids (BCAAs), and glutamate-related features exhibited strong correlations with cognitive impairment, clinical stage, and brain amyloid-ß deposition (n = 421). These features demonstrated synergistic performances across clinical stages and subpopulations and enhanced the differentiation of AD stages beyond demographics and Apolipoprotein E ε4 allele (APOE-ε4). We validated their performances in eight data sets (total n = 7685) obtained from Alzheimer's Disease Neuroimaging Initiative (ADNI) and Religious Orders Study and Memory and Aging Project (ROSMAP). Importantly, identified features are linked to blood ammonia homeostasis. We further confirmed the elevated ammonia level through AD development (n = 1060). Our findings highlight AD as a metabolic disease and emphasize the metabolite-mediated ammonia disturbance in AD and its potential as a signature and therapeutic target for AD.

Microbiome structure and function in parallel full-scale aerobic granular sludge and activated sludge processes.

Aerobic granular sludge (AGS) and conventional activated sludge (CAS) are two different biological wastewater treatment processes. AGS consists of self-immobilised microorganisms that are transformed into spherical biofilms, whereas CAS has floccular sludge of lower density. In this study, we investigated the treatment performance and microbiome dynamics of two full-scale AGS reactors and a parallel CAS system at a municipal WWTP in Sweden. Both systems produced low effluent concentrations, with some fluctuations in phosphate and nitrate mainly due to variations in organic substrate availability. The microbial diversity was slightly higher in the AGS, with different dynamics in the microbiome over time. Seasonal periodicity was observed in both sludge types, with a larger shift in the CAS microbiome compared to the AGS. Groups important for reactor function, such as ammonia-oxidising bacteria (AOB), nitrite-oxidising bacteria (NOB), polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs), followed similar trends in both systems, with higher relative abundances of PAOs and GAOs in the AGS. However, microbial composition and dynamics differed between the two systems at the genus level. For instance, among PAOs, Tetrasphaera was more prevalent in the AGS, while Dechloromonas was more common in the CAS. Among NOB, Ca. Nitrotoga had a higher relative abundance in the AGS, while Nitrospira was the main nitrifier in the CAS. Furthermore, network analysis revealed the clustering of the various genera within the guilds to modules with different temporal patterns, suggesting functional redundancy in both AGS and CAS. KEY POINTS: • Microbial community succession in parallel full-scale aerobic granular sludge (AGS) and conventional activated sludge (CAS) processes. • Higher periodicity in microbial community structure in CAS compared to in AGS. • Similar functional groups between AGS and CAS but different composition and dynamics at genus level.

Irons differently modulate bacterial guilds for leading to varied efficiencies in simultaneous nitrification and denitrification (SND) within four aerobic bioreactors.

As a novel biological wastewater nitrogen removal technology, simultaneous nitrification and denitrification (SND) has gained increasing attention. Iron, serving as a viable material, has been shown to influence nitrogen removal. However, the precise impact of iron on the SND process and microbiome remains unclear. In this study, bioreactors amended with iron of varying valences were evaluated for total nitrogen (TN) removal efficiencies under aerobic conditions. The acclimated control reactor without iron addition (NCR) exhibited high ammonia nitrogen (AN) removal efficiency (98.9%), but relatively low TN removal (78.6%) due to limited denitrification. The reactor containing zero-valent iron (Fe0R) demonstrated the highest SND rate of 92.3% with enhanced aerobic denitrification, albeit with lower AN removal (84.1%). Significantly lower SND efficiencies were observed in reactors with ferrous (Fe2R, 66.3%) and ferric (Fe3R, 58.2%) iron. Distinct bacterial communities involved in nitrogen metabolisms were detected in these bioreactors. The presence of complete ammonium oxidation (comammox) genus Nitrospira and anammox bacteria Candidatus Brocadia characterized efficient AN removal in NCR. The relatively low abundance of aerobic denitrifiers in NCR hindered denitrification. Fe0R exhibited highly abundant but low-efficiency methanotrophic ammonium oxidizers, Methylomonas and Methyloparacoccus, along with diverse aerobic denitrifiers, resulting in lower AN removal but an efficient SND process. Conversely, the presence of Fe2+/Fe3+ constrained the denitrifying community, contributing to lower TN removal efficiency via inefficient denitrification. Therefore, different valent irons modulated the strength of nitrification and denitrification through the assembly of key microbial communities, providing insight for microbiome modulation in nitrogen-rich wastewater treatment.

Modulating the Activity and SO2 Resistance of α-Fe2O3 Catalysts for NH3-SCR of NOx via Crystal Facet Engineering.

The development of Fe-based catalysts for the selective catalytic reduction of NOx by NH3 (NH3-SCR of NOx) has garnered significant attention due to their exceptional SO2 resistance. However, the influence of different sulfur-containing species (e.g., ferric sulfates and ammonium sulfates) on the NH3-SCR activity of Fe-based catalysts as well as its dependence on exposed crystal facets of Fe2O3 has not been revealed. This work disclosed that nanorod-like α-Fe2O3 (Fe2O3-NR) predominantly exposing (110) facet performed better than nanosheet-like α-Fe2O3 (Fe2O3-NS) predominantly exposing (001) facet in NH3-SCR reaction, due to the advantages of Fe2O3-NR in redox properties and surface acidity. Furthermore, the results of the SO2/H2O resistance test at a critical temperature of 250 °C, catalytic performance evaluations on Fe2O3-NR and Fe2O3-NS sulfated by SO2 + O2 or deposited with NH4HSO4 (ABS), and systematic characterization revealed that the reactivity of ammonium sulfates on Fe2O3 catalysts to NO(+O2) contributed to their improved catalytic performance, while ferric sulfates showed enhancing and inhibiting effects on NH3-SCR activity on Fe2O3-NR and Fe2O3-NS, respectively; despite this, Fe2O3-NR showed higher affinity for SO2 + O2. This work set a milestone in understanding the NH3-SCR reaction on Fe2O3 catalysts in the presence of SO2 from the aspect of crystal facet engineering.

Impacts assessment of nitrification inhibitors on U.S. agricultural emissions of reactive nitrogen gases.

Fertilizer-intensive agriculture leads to emissions of reactive nitrogen (Nr), posing threats to climate via nitrous oxide (N2O) and to air quality and human health via nitric oxide (NO) and ammonia (NH3) that form ozone and particulate matter (PM) downwind. Adding nitrification inhibitors (NIs) to fertilizers can mitigate N2O and NO emissions but may stimulate NH3 emissions. Quantifying the net effects of these trade-offs requires spatially resolving changes in emissions and associated impacts. We introduce an assessment framework to quantify such trade-off effects. It deploys an agroecosystem model with enhanced capabilities to predict emissions of Nr with or without the use of NIs, and a social cost of greenhouse gas to monetize the impacts of N2O on climate. The framework also incorporates reduced-complexity air quality and health models to monetize associated impacts of NO and NH3 emissions on human health downwind via ozone and PM. Evaluation of our model against available field measurements showed that it captured the direction of emission changes but underestimated reductions in N2O and overestimated increases in NH3 emissions. The model estimated that, averaged over applicable U.S. agricultural soils, NIs could reduce N2O and NO emissions by an average of 11% and 16%, respectively, while stimulating NH3 emissions by 87%. Impacts are largest in regions with moderate soil temperatures and occur mostly within two to three months of N fertilizer and NI application. An alternative estimate of NI-induced emission changes was obtained by multiplying the baseline emissions from the agroecosystem model by the reported relative changes in Nr emissions suggested from a global meta-analysis: -44% for N2O, -24% for NO and +20% for NH3. Monetized assessments indicate that on an annual scale, NI-induced harms from increased NH3 emissions outweigh (8.5-33.8 times) the benefits of reducing NO and N2O emissions in all agricultural regions, according to model-based estimates. Even under meta-analysis-based estimates, NI-induced damages exceed benefits by a factor of 1.1-4. Our study highlights the importance of considering multiple pollutants when assessing NIs, and underscores the need to mitigate NH3 emissions. Further field studies are needed to evaluate the robustness of multi-pollutant assessments.

Synergistic effects of peracetic acid and free ammonia pretreatment on anaerobic fermentation of waste activated sludge to promote short-chain fatty acid production for polyhydroxyalkanoate biosynthesis: Mechanisms and optimization.

Peracetic acid (PAA) combined with free ammonia (FA) pretreatment can be utilized to promote anaerobic fermentation (AF) of waste activated sludge (WAS) to produce short-chain fatty acids (SCFAs), and the resulting SCFAs are desirable carbon sources (C-sources) for polyhydroxyalkanoate (PHA) biosynthesis. This work aimed to determine the optimum conditions for PAA + FA pretreatment of sludge AF and the feasibility of using anaerobic fermentation liquor (AFL) for PHA production. To reveal the mechanisms of integrated pretreatment, the impacts of PAA + FA pretreatment on different stages of sludge AF and changes in the microbial community structure were explored. The experimental results showed that the maximum SCFA yield reached 491.35 ± 6.02 mg COD/g VSS on day 5 after pretreatment with 0.1 g PAA/g VSS +70 mg FA/L, which was significantly greater than that resulting from PAA or FA pretreatment alone. The mechanism analysis showed that PAA + FA pretreatment promoted sludge solubilization but strongly inhibited methanogenesis. According to the analysis of the microbial community, PAA + FA pretreatment changed the microbial community structure and promoted the enrichment of bacteria related to hydrolysis and acidification, and Proteiniclasticum, Macellibacteroides and Petrimonas became the dominant hydrolytic and acidifying bacteria. Finally, after alkali treatment, the AFL was utilized for batch-mode PHA production, and a maximum PHA yield of 55.05 wt% was achieved after five operation periods.

Reactive Force Field Molecular Dynamics Investigation of NH3 Generation Mechanism during Protein Pyrolysis Process.

The mechanism of ammonia formation during the pyrolysis of proteins in biomass is currently unclear. To further investigate this issue, this study employed the AMS 2023.104 software to select proteins (actual proteins) as the model compounds and the amino acids contained within them (assembled amino acids) as the comparative models. ReaxFF molecular dynamics simulations were conducted to explore the nitrogen transformation and NH3 generation mechanisms in three-phase products (char, tar, and gas) during protein pyrolysis. The research results revealed several key findings. Regardless of whether the model compounds are actual proteins or assembled amino acids, NH3 is the primary nitrogen-containing product during pyrolysis. However, as the temperature rises to higher levels, such as 2000 K and 2500 K, the amount of NH3 decreases significantly in the later stages of pyrolysis, indicating that it is being converted into other nitrogen-bearing species, such as HCN and N2. Simultaneously, we also observed significant differences between the pyrolysis processes of actual proteins and assembled amino acids. Notably, at 2000 K, the amount of NH3 generated from the pyrolysis of assembled amino acids was twice that of actual proteins. This discrepancy mainly stems from the inherent structural differences between proteins and amino acids. In proteins, nitrogen is predominantly present in a network-like structure (NH-N), which shields it from direct external exposure, thus requiring more energy for nitrogen to participate in pyrolysis reactions, making it more difficult for NH3 to form. Conversely, assembled amino acids can release NH3 through a simpler deamination process, leading to a significant increase in NH3 production during their pyrolysis.

Ammonia Detection by Electronic Noses for a Safer Work Environment.

Providing employees with proper work conditions should be one of the main concerns of any employer. Even so, in many cases, work shifts chronically expose the workers to a wide range of potentially harmful compounds, such as ammonia. Ammonia has been present in the composition of products commonly used in a wide range of industries, namely production in lines, and also laboratories, schools, hospitals, and others. Chronic exposure to ammonia can yield several diseases, such as irritation and pruritus, as well as inflammation of ocular, cutaneous, and respiratory tissues. In more extreme cases, exposure to ammonia is also related to dyspnea, progressive cyanosis, and pulmonary edema. As such, the use of ammonia needs to be properly regulated and monitored to ensure safer work environments. The Occupational Safety and Health Administration and the European Agency for Safety and Health at Work have already commissioned regulations on the acceptable limits of exposure to ammonia. Nevertheless, the monitoring of ammonia gas is still not normalized because appropriate sensors can be difficult to find as commercially available products. To help promote promising methods of developing ammonia sensors, this work will compile and compare the results published so far.

Risk Stratification Using Right Ventricular Longitudinal Strain Ratio Derived from 13N-Ammonia PET in Patients with Ischemic Heart Disease.

Purpose To investigate whether right ventricular (RV) myocardial strain ratio (RVMSR) assessed using nitrogen 13 ammonia (13N-NH3) PET can predict cardiovascular events in patients with ischemic heart disease (IHD). Materials and Methods This retrospective study included 480 consecutive patients (mean age, 66 years ± 12 [SD]; 334 males and 146 females) with IHD who underwent 13N-NH3 PET. RVMSR was defined as the ratio of RV strain during stress to that at rest. The primary end point was major adverse cardiac events (MACEs), defined as cardiac death or heart failure hospitalization. The ability of RVMSR to predict MACE was assessed using receiver operating characteristic (ROC) curve and Kaplan-Meier analyses. Cox proportional hazards regression analysis was used to calculate hazard ratios (HRs) with 95% CIs. Results ROC curve analysis identified a sensitivity and specificity of 84% and 82%, respectively, for predicting MACE from RVMSR. Patients with reduced RVMSR (<110.2) displayed a significantly higher rate of MACE than those with a preserved RVMSR (34 of 240 vs four of 240; P < .001). Cox proportional hazards regression analysis of imaging parameters, including myocardial flow reserve, indicated that RVMSR was an independent predictor of MACE (HR, 0.94 [95% CI: 0.92, 0.97]; P < .001). Conclusion RVMSR was an independent predictor of MACE and has potential to aid in the risk stratification of patients with IHD. Keywords: Right Ventricular Myocardial Strain Ratio, Myocardial Flow Reserve, Ischemic Heart Disease, 13N-Ammonia Positron Emission Tomography Supplemental material is available for this article. © RSNA, 2024.

The superiority of hydrophilic polyurethane in comammox-dominant ammonia oxidation during low-strength wastewater treatment.

Carriers have been extensively employed to enhance nitrification performance during low-strength wastewater treatment by retaining slow-growing ammonia oxidizing microorganisms (AOMs). Still, there is a dearth of systematic understanding of biofilm properties and microbial community structure formed on different carriers. In this study, hydrophilic polyurethane foam (PUF) carriers were prepared and compared with five widely used commercial carriers, namely Kaldness 3, Biochip, activated carbon, volcanic rock, and zeolite. The results indicated that the biofilms formed on carriers enhanced microbial ammonia oxidation activity. Additionally, the biofilm developed on the PUF demonstrated the most superior performance among all selected carriers, not only exhibiting the highest abundant and the most active AOMs, with amoA gene abundance of 1.41 × 1013 copies/m3 and specific ammonia oxidation rate of 9.84 g NH4+-N/(m3 × h), but also possessing a compact structure, with 3.41 kg VSS/m3 and 46.83 mg extracellular polymeric substances/g VSS. The high-throughput sequencing analysis revealed that the comammox (CMX) Nitrospira dominated on biofilm due to the intrinsically low apparent half-saturation constant for substrate. A unique ecological community structure was established on PUF, characterized by low species diversity and high homogeneity in alignment with community characteristics of CMX. The biofilms on PUF contributed to the proliferation of CMX Nitrospira dominated by Nitrospira nitrosa, achieving the highest proportion among colonial three AOMs at 86.58 %. The appropriate average pore size, superior hydrophilicity, and large specific surface area of PUF carriers provided a robust foundation for the exceptional ammonia oxidation performance of the formed biofilms.

Metabolic potential of Nitrososphaera-associated clades.

Soil ammonia-oxidizing archaea (AOA) play a crucial role in converting ammonia to nitrite, thereby mobilizing reactive nitrogen species into their soluble form, with a significant impact on nitrogen losses from terrestrial soils. Yet, our knowledge regarding their diversity and functions remains limited. In this study, we reconstructed 97 high-quality AOA metagenome-assembled genomes (MAGs) from 180 soil samples collected in Central Germany during 2014-2019 summers. These MAGs were affiliated with the order Nitrososphaerales and clustered into four family-level clades (NS-α/γ/δ/ε). Among these MAGs, 75 belonged to the most abundant but least understood δ-clade. Within the δ-clade, the amoA genes in three MAGs from neutral soils showed a 99.5% similarity to the fosmid clone 54d9, which has served as representative of the δ-clade for the past two decades since even today no cultivated representatives are available. Seventy-two MAGs constituted a distinct δ sub-clade, and their abundance and expression activity were more than twice that of other MAGs in slightly acidic soils. Unlike the less abundant clades (α, γ, and ε), the δ-MAGs possessed multiple highly expressed intracellular and extracellular carbohydrate-active enzymes responsible for carbohydrate binding (CBM32) and degradation (GH5), along with highly expressed genes involved in ammonia oxidation. Together, these results suggest metabolic versatility of uncultured soil AOA and a potential mixotrophic or chemolithoheterotrophic lifestyle among 54d9-like AOA.

Ammonium-derived nitrous oxide is a global source in streams.

Global riverine nitrous oxide (N2O) emissions have increased more than 4-fold in the last century. It has been estimated that the hyporheic zones in small streams alone may contribute approximately 85% of these N2O emissions. However, the mechanisms and pathways controlling hyporheic N2O production in stream ecosystems remain unknown. Here, we report that ammonia-derived pathways, rather than the nitrate-derived pathways, are the dominant hyporheic N2O sources (69.6 ± 2.1%) in agricultural streams around the world. The N2O fluxes are mainly in positive correlation with ammonia. The potential N2O metabolic pathways of metagenome-assembled genomes (MAGs) provides evidence that nitrifying bacteria contain greater abundances of N2O production-related genes than denitrifying bacteria. Taken together, this study highlights the importance of mitigating agriculturally derived ammonium in low-order agricultural streams in controlling N2O emissions. Global models of riverine ecosystems need to better represent ammonia-derived pathways for accurately estimating and predicting riverine N2O emissions.

Dating Ammonia-Oxidizing Bacteria with Abundant Eukaryotic Fossils.

Evolution of a complete nitrogen (N) cycle relies on the onset of ammonia oxidation, which aerobically converts ammonia to nitrogen oxides. However, accurate estimation of the antiquity of ammonia-oxidizing bacteria (AOB) remains challenging because AOB-specific fossils are absent and bacterial fossils amenable to calibrate molecular clocks are rare. Leveraging the ancient endosymbiosis of mitochondria and plastid, as well as using state-of-the-art Bayesian sequential dating approach, we obtained a timeline of AOB evolution calibrated largely by eukaryotic fossils. We show that the first AOB evolved in marine Gammaproteobacteria (Gamma-AOB) and emerged between 2.1 and 1.9 billion years ago (Ga), thus postdating the Great Oxidation Event (GOE; 2.4 to 2.32 Ga). To reconcile the sedimentary N isotopic signatures of ammonia oxidation occurring near the GOE, we propose that ammonia oxidation likely occurred at the common ancestor of Gamma-AOB and Gammaproteobacterial methanotrophs, or the actinobacterial/verrucomicrobial methanotrophs which are known to have ammonia oxidation activities. It is also likely that nitrite was transported from the terrestrial habitats where ammonia oxidation by archaea took place. Further, we show that the Gamma-AOB predated the anaerobic ammonia-oxidizing (anammox) bacteria, implying that the emergence of anammox was constrained by the availability of dedicated ammonia oxidizers which produce nitrite to fuel anammox. Our work supports a new hypothesis that N redox cycle involving nitrogen oxides evolved rather late in the ocean.

Using predictive models unravel the potential of titanium oxide-loaded activated carbon for the removal of leachate ammoniacal nitrogen.

The TiO2 nanocomposite efficiency was determined under optimized conditions with activated carbon to remove ammoniacal nitrogen (NH3-N) from the leachate sample. In this work, the facile impregnation and pyrolysis synthesis method was employed to prepare the nanocomposite, and their formation was confirmed using the FESEM, FTIR, XRD, and Raman studies. In contrast, Raman phonon mode intensity ratio ID/IG increases from 2.094 to 2.311, indicating the increase of electronic conductivity and defects with the loading of TiO2 nanoparticles. The experimental optimal conditions for achieving maximum NH3-N removal of 75.8% were found to be a pH of 7, an adsorbent mass of 1.75 mg/L, and a temperature of 30 °C, with a corresponding time of 160 min. The experimental data were effectively fitted with several isotherms (Freundlich, Hill, Khan, Redlich-Peterson, Toth, and Koble-Corrigan). The notably elevated R2 value of 0.99 and a lower ARE % of 14.61 strongly support the assertion that the pseudo-second-order model compromises a superior depiction of the NH3-N reduction process. Furthermore, an effective central composite design (CCD) of response surface methodology (RSM) was employed, and the lower RMSE value, precisely 0.45, demonstrated minimal disparity between the experimentally determined NH3-N removal percentages and those predicted by the model. The subsequent utilization of the desirability function allowed us to attain actual variable experimental conditions.

A hydrogel-modified electrochemical biosensor for the rapid detection of ammonia­nitrogen-resistant bacteria.

Ammonia­nitrogen wastewater is one of the main pollutants in the current environment. Rapid detection of microorganisms resistant to ammonia­nitrogen provides a basis for bioremediation of ammonia­nitrogen contaminated sites. This study uses electrochemical analysis for efficiently detecting of ammonia-resistant bacteria, utilizing a commercially available, low-cost screen-printed electrode (SPE) modified with agarose-based hydrogel (gel) or graphene oxide (GO). At the same time, the study employed electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) to monitor bacterial growth, revealing Escherichia coli (E. coli) inhibition upon ammonia­nitrogen addition, while Raoultella terrigena (RN1) and Pseudomonas (RN2) exhibit tolerance. The method provides sensitivity results in <45 min, which is significantly faster than traditional methods. RN1 and RN2 exhibit promising ammonia­nitrogen removal rates, reaching up to 81 % and 92 %, respectively. This study aimed to develop an effective electrochemical method for rapidly detecting the sensitivity of microorganisms to ammonia­nitrogen. The method offers advantages such as high speed, efficiency, and cost-effectiveness, potentially providing valuable microbial resources for mitigating ammonia nitrogen wastewater pollution.

Nile tilapia (Oreochromis niloticus) show high tolerance to acute ammonia exposure but lose metabolic scope during prolonged exposure at low concentration.

Ammonia is a respiratory gas that is produced during the process of protein deamination. In the unionised form (NH3), it readily crosses biological membranes and is highly toxic to fish. In the present study we examined the effects of unionized ammonia (UIA), on the resting oxygen consumption (MO2), ventilation frequency (fV), heart rate (HR) and heart rate variability (HRV) in Nile tilapia (Oreochromis niloticus). Fish were either exposed to progressively increasing UIA concentrations, up to 97 µM over a 5 h period, or to a constant UIA level of 7 µM over a 24 h period. For both treatment groups resting MO2, HR and fV were recorded as physiological variables. Relative to the control group, the fish groups exposed to the incremental UIA levels did not exhibit significant changes in their MO2, HR and fV at UIA concentrations of 4, 10, 35, or 61 µM compared to control fish. Exposure to 97 µM UIA, however, elicited abrupt and significant downregulations (p < 0.05) in all three responses, as MO2, HR and fv decreased by 25, 54 and 76 % respectively, compared to control measurements. Heart rate became increasingly irregular with increasing UIA concentrations, and heart rate variability was significantly increased at 61 and 97 µM UIA. Prolonged exposure elicited significant changes at exposure 7 µM UIA. Standard (SMR) and maximum metabolic rate (MMR) were significantly reduced, as was the corresponding fV and HR. It is evident from this study that Nile tilapia is tolerant to short term exposure to UIA up to 61 µM but experience a significant metabolic change under conditions of prolonged UIA exposures even at low concentrations.

Intravenous versus oral 'L-ornithine-L-aspartate' in overt hepatic encephalopathy: a randomized comparative study.

Hepatic encephalopathy (HE), a morbid ordeal affecting chronic liver disease patients always insists for the search of a rational, superior & infallible agent beyond the time-proven standards i.e., Lactulose & Rifaximin. In this RCT, we compared the efficacy of intravenous (IV) L-ornithine-L-aspartate(LOLA) versus Oral LOLA in patients with chronic liver disease(CLD) enduring overt Hepatic Encephalopathy(OHE). 40 CLD patients with OHE were randomly assigned IV or oral LOLA in a 1:1 ratio. Patients were graded for HE and monitored for serum ammonia levels from day 1 to day 5. The aim was to compare IV versus oral LOLA efficacy in HE grades improvement and its correlation with ammonia levels. The study was registered with clinical trials registry-India, CTRI/2020/12/029943. Baseline characteristics of patients in both groups were similar. The mean difference in ammonia levels from day 1 to day 5 was 55.4 ± 32.58 µmol/L in the IV LOLA group and 60.75 ± 13.82 µmol/L in the oral LOLA group (p = 0.511). Significant reductions in ammonia levels were observed from day 1 to day 5 within each group (p < 0.001). HE grade & ammonia correlated positively in both groups. LOLA, regardless of administration route, has demonstrated efficacy in OHE.

Integration of anaerobic digestion and electrodialysis for methane yield promotion and in-situ ammonium recovery.

Ammonia inhibition is a common issue encountered in anaerobic digestion (AD) when treating nitrogen-rich substrates. This study proposed a novel approach, the electrodialysis-integrated AD (ADED) system, for in-situ recovery of ammonium (NH4+) while simultaneously enhancing AD performance. The ADED reactor was operated at two different NH4+-N concentrations (5,000 mg/L and 10,000 mg/L) to evaluate its performance against a conventional AD reactor. The results indicate that the ADED technology effectively reduced the NH4+-N concentration to below 2,000 mg/L, achieving this with a competitive energy consumption. Moreover, the ADED reactor demonstrated a 1.43-fold improvement in methane production when the influent NH4+-N was 5,000 mg/L, and it effectively prevented complete inhibition of methane production at the influent NH4+-N of 10,000 mg/L. The life cycle impact assessment reveals that ADED technology offers a more environmentally friendly alternative by recovering valuable fertilizer from the AD system.

Effects of crayfish shell powder and bamboo-derived biochar on nitrogen conversion, bacterial community and nitrogen functional genes during pig manure composting.

This study investigated the effects of crayfish shell powder (CSP) and bamboo-derived biochar (BDB) on nitrogen metabolism, bacterial community and nitrogen functional genes during pig manure composting. Four treatments were established: CP (with no additives), TP1 (5 % BDB), TP2 (5 % CSP) and TP3 (2.5 % BDB + 2.5 % CSP). Compared to CP, the germination index (GI) of TP reached > 85 % 10 days earlier. Meanwhile, TP3 reduced NH3 and N2O emissions by 42.90 % and 65.9 %, respectively, while increased TN (total nitrogen) concentration by 5.43 g/kg. Furthermore, additives changed the bacterial structure and formed a beneficial symbiotic relationship with essential N-preserving bacteria, thereby enhancing nitrogen retention throughout the composting process. Metagenomic analysis revealed that additives upregulated nitrification genes and downregulated denitrification and nitrate reduction genes, ultimately improving nitrogen cycling and mitigating NH3 and N2O emissions. In conclusion, the results confirmed that TP3 was the most effective treatment in reducing nitrogen loss.