Ammonia Concentration Research Articles

Modulation of microbiota composition and markers of gut health after in vitro dynamic colonic fermentation of plant sterol-enriched wholemeal rye bread.

A human oral phase followed by a dynamic gastrointestinal digestion and colonic fermentation (simgi®) has been applied to wholemeal rye bread (WRB) and PS-enriched WRB (PS-WRB). The aim of this study was to evaluate the impact of these solid and high-fiber food matrices on the metabolism of PS, modulation of the microbiota and production of short-chain fatty acids (SCFA) and ammonium ion after a simulated chronic intake (5days). In both breads, campesterol, campestanol, stigmasterol, β-sitosterol, sitostanol, Δ5-avenasterol, Δ5,24-stigmastadienol, Δ7-stigmastenol, and Δ7-avenasterol were identified, of which only β-sitosterol was metabolized to sitostenone after PS-WRB treatment. The presence of fiber in both breads exerted a prebiotic effect after fermentation by the increase in Firmicutes (Lactobacillus genus, maximum abundance of 89-99%) and Actinobacteria (Bifidobacterium genus, maximum abundance of 30-31%), reflected in an increase of SCFA content. The reduction of proteolytic activity confirmed by the decrease in ammonium ion contents is related to a reduction in the Proteobacteria phylum. Thus, PS-WRB could be considered as a healthy staple food choice since, besides the known hypocholesterolemic effect of PS, rye bread fiber preserves the beneficial microbiota and exerts a positive impact on markers of gut health.

Spatiotemporal distribution of marine aerosols and gaseous species over the North Pacific Ocean.

Observational studies of marine aerosols are essential for understanding the global aerosol budget and its environmental impacts. This study presents simultaneous in-situ measurements of major ionic components (Cl-, NO3-, SO42-, NH4+, K+, Ca2+, Na+, and Mg2+) in aerosols and gaseous species (HCl, HNO3, HONO, SO2, and NH3) over the North Pacific Ocean from July 4 to 15 and September 19 to October 3, 2022. Using high temporal resolution instruments aboard the Republic of Korea's icebreaker research vessel Araon, this study aimed to (1) report the spatial and temporal distributions of aerosols and gaseous species, (2) estimate the source contributions of continental anthropogenic pollutants, and (3) assess the influence of aerosol chemical composition and gaseous species on aerosol acidity and water content. Our results revealed a significant decline in anthropogenic contributions, from 72.4±11.2% in the Yellow Sea and East Sea to 32.0±10.8% in the remote Pacific, accompanied by an increase in natural aerosols from 27.6±11.2% to 68.0±10.8%. Elevated concentrations of ammonia (NH3) and nitrous acid (HONO) were observed in the remote ocean, likely associated with the marine environment and biological activities. This increase in NH3, along with a decrease in sulfate concentrations, contributed to the formation of more alkaline aerosols in the remote ocean. Despite the limited availability of previous studies for direct comparisons, our findings align with observed trends and highlight the unique physicochemical properties of marine aerosols. These results enhance our understanding for the interactions between continental pollutants and marine environments, emphasizing the distinct characteristics of marine aerosols and their potential role in modifying atmospheric processes and influencing climate change.

Fabrication of microplastic-free biomass-based Masks: Enhanced Multi-functionality with All-natural fibers

With the coronavirus-2019 epidemic, disposable surgical masks have become a common personal protective necessity. However, off-the-shelf masks have low filtration efficiency and short service life and can only physically isolate pathogens, easily leading to secondary infection and cross-infection between users. Additionally, they produce debris and microplastics, which can be inhaled by the human body and cause serious diseases. To address this, this study introduced a brand-new, microplastic-free, long-life, biodegradable, self-disinfecting, and gas-sensitive mask made of basal dialdehyde-chitosan crosslinked animal-collagen/plant composite fibers (CP-Mask) with an asymmetric bilayer structure using scalable paper-processing technology. The CP-Mask demonstrated outstanding filtration performance (95.9%) for particulate matter with various sizes and constantly maintained filtration efficiency even after 20 friction cycles. The CP-Mask also exhibited stable and lasting antibacterial properties, with significant inhibition rates of 99.21% for Staphylococcus aureus and 98.86% for Escherichia coli and could effectively filter bacterial aerosols. In addition, CP-Mask realized the real-time detection of respiratory ammonia concentration and timely identified the ammonia level. The average response value was 68.26%, and the average response time was 159.3 s, presenting good circulatory stability and is suitable for early diagnosis of ammonia-related diseases. Breakthrough, the origin of natural ingredients, fundamentally makes CP-Mask less likely to emit microplastics than commercially available masks and endows it with complete biodegradability in soil within three months, eliminating the risk of microplastic inhalation from the source. The proposed CP-Mask provides a new idea to facilitate personal health monitoring and portability of medical protection equipment regarding biocompatibility, biodegradability, self-disinfection, and ammonia sensing ability.

Performance of 1-year-old camel calves fed a basal ration of alfalfa hay supplemented with different levels of concentrate

BackgroundThe use of a high-concentrate diet in fattening camels may have significant effects on growth performance and digestion as well as economic returns. This experiment was designed to study the effects of feeding different levels of concentrate in their diet on growth performance and digestion in a desert climate.MethodsEighteen 12-month-old male camel calves were used, and divided into three treatments of six each. The concentrate was administered based on their body weight (BW) at 0.7 (low), 1.0 (medium), and 1.3% (high), with free access to alfalfa and water. The experiment lasted for 6 months, in which digestibility trials took place at 14, 16, and 18 months of age, which corresponded to 2, 4, and 6 months of the experimental period.ResultsNo significant variations were observed in final BW, BW changes, or average daily gain among feeding treatments. Increasing the concentrate level had a negative effect on roughage intake, impacting the roughage-to-concentrate ratio (P < 0.05) and neutral detergent fiber digestibility (P < 0.05). Increasing concentrate levels significantly increased total intake (P < 0.05), leading to a worse feed conversion ratio (P < 0.05). However, animal age had no negative effect on nutrient digestibility, and there were no interactions between concentrate supplement level and animal age. Significant increases in plasma total protein (P < 0.05) and urea (P < 0.05) were observed when the leve lof concentrate was increased. A similar trend was observed in rumen ammonia concentration. Camel calves fed low vs. medium or high levels of concentrate showed a greater rumen pH (P < 0.05), which was linked to a lower concentration of volatile fatty acids (P < 0.010).ConclusionsThe present study concluded that yearling camel calves receiving different levels of concentrate with ad lib alfalfa hay could cover their nutrient requirements for maintenance and growth with a daily gain of 630 g/day when the level of concentrate was limited to 0.7% of BW and the total intake was only around 1.65% of BW, or 70.6 g/kg metabolic BW.

Relationship assessment of microbial community and cometabolic consumption of 2-chlorophenol

The relationship of microbial community and cometabolic consumption of 2-chlorophenol (2-CP) in a nitrifying sequencing batch reactor (SBR) was studied. The assessment of the population dynamics of the nitrifying sludge during the cometabolic 2-CP consumption with increasing ammonium (NH4+) concentrations in the SBR showed the presence of 39 different species of which 10 were always present in all cycles. Fifty-five percent of the species found were grouped as Proteobacteria (45% as β-proteobacteria and 10% as γ-proteobacteria class), 30% as Acidobacteria, and 15% as Deinococcus-Thermus phyla. NH4+ and cometabolic 2-CP consumption could be related to the presence and permanence of ammonium-oxidizing bacteria (AOB) species and heterotrophic bacteria, while the complete nitrification to the presence of nitrite-oxidizing bacteria (NOB) species. A correlation analysis showed that the complete and stable nitrifying performance (NH4+ consumption efficiencies (ENH4+-N) > 99% and nitrate production yields (YNO3−-N) between 0.93 and 0.99), as well as the increase in specific rates (ammonium (qNH4+-N) and 2-CP (q2-CP-C) consumption and nitrate production (qNO3−-N)), was associated with the homogeneity of the bacterial community (J index = 0.99). The increase in the proportion of individuals of AOB species such as Nitrosomonas oligotropha and Nitrosomonas marina was associated with the increase in qNH4+-N (r ≥ 0.69) and q2-CP-C (r ≥ 0.64) and, therefore, with the 2-CP cometabolic consumption in the SBR. Finally, the increase in the proportion of individuals of heterotrophic species such as Dokdonella ginsengisoli, Deinococcus peraridilitoris, Truepera radiovictrix, and Stenotrophobacter terrae was associated with the increase in q2-CP-C (r ≥ 0.59).Key points• Thirty-nine bacterial species were identified in the nitrifying sludge population of the SBR.• β-Proteobacteria and Acidobacteria were the prevalent (85%) bacterial groups.• AOB and heterotrophic bacteria participate in NH4+ and cometabolic 2-CP consumption.Graphical abstract

Assessing a Multilayered Hydrophilic–Electrocatalytic Forward Osmosis Membrane for Ammonia Electro-Oxidation

Over the years, the ammonia concentration in water streams and the environment is increasing at an alarming rate. Many membrane-based processes have been studied to alleviate this concern via adsorption and filtration. On the other hand, ammonia electro-oxidation is an approach of particular interest owing to its energetic and environmental benefits. Thus, a plausible alternative to combine these two paths is by using an electroconductive membrane (ECM) to complete the ammonia oxidation reaction (AOR). This combination of processes has been studied very limitedly, and it can be an area for development. Herein, we developed a multilayered membrane with hydrophilic and electrocatalytic properties capable of completing the AOR. The porosity of carbon black (CB) particles was embedded in the polymeric support (CBES) and the active side was composed of a triple layer consisting of polyamide/CB/Pt nanoparticles (PA:CB:Pt). The CBES increased the membrane porosity, changed the pores morphology, and enhanced water permeability and electroconductivity. The deposition of each layer was monitored and corroborated physically, chemically, and electrochemically. The final membrane CBES:PA:VXC:Pt reached higher water flux than its PSF counterpart (3.9 ± 0.3 LMH), had a hydrophilic surface (water contact angle: 19.8 ± 0.4°), and achieved the AOR at −0.3 V vs. Ag/AgCl. Our results suggest that ECMs with conductive material in both membrane layers enhanced their electrical properties. Moreover, this study is proof-of-concept that the AOR can be succeeded by a polymeric FO-ECMs.

Differences in Biogeographic Patterns and Mechanisms of Assembly in Estuarine Bacterial and Protist Communities.

As transitional ecosystems between land and sea, estuaries are characterized by a unique environment that supports complex and diverse microbial communities. A comprehensive analysis of microbial diversity and ecological processes at different trophic levels is crucial for understanding the ecological functions of estuarine ecosystems. In this study, we systematically analyzed the diversity patterns, community assembly, and environmental adaptability of bacterial and protist communities using high-throughput sequencing techniques. The results revealed a higher alpha diversity for the bacteria than for protists, and the beta diversity pattern was dominated by species turnover in both communities. In addition, the two community assemblages were shown to be dominated by deterministic and stochastic processes, respectively. Furthermore, our results emphasized the influence of the local species pool on microbial communities and the fact that, at larger scales, geographic factors played a more significant role than environmental factors in driving microbial community variation. The study also revealed differences in environmental adaptability among different microbial types. Bacteria exhibited strong adaptability to salinity, while protists demonstrated greater resilience to variations in dissolved oxygen, nitrate, and ammonium concentrations. These results suggested differences in environmental adaptation strategies among microorganisms at different trophic levels, with bacteria demonstrating a more pronounced environmental filtering effect.

The Effect of Biochar Application Rates on Soil Fertility and Phyto-Availability of Heavy Metals is Dependent on Soil Type and pH

ABSTRACT The effect of biochar application rate on soil nutrient and heavy metal phyto-availability may differ depending on soil properties. To investigate this hypothesis, a pot experiment was conducted with three soil types (yellow soil (YS), yellow-brown soil (YBS) (slightly alkaline), and calcareous soil (CS) (neutral soil)), using five biochar application rates: 0, 0.1%. 1.0%, 2.5%, and 5.0%. The results showed that the total organic carbon increased progressively in all three soil types, while the labile organic carbon only increased progressively in yellow soil with an increasing rate of biochar from 0% to 5%. The ammonia and Olsen-phosphorus concentrations increased with higher biochar rates for the slightly alkaline soils, but decreased significantly at higher rate for the neutral soil. Additionally, the application of biochar at 2.5% and 5.0% significantly reduced soil nitrate concentrations in slightly alkaline YS soil (by 31.10% and 37.83%) and YBS soil (by 65.96% and 76.70%) compared to the control, but did not change significantly in the neutral soil. Biochar application increased soil exchangeable potassium (K) concentration more significantly in high K soils compared to low K soil. The exchangeable calcium (Ca) concentration increased with increasing biochar rate if the exchangeable Ca was < 10.6 cmol kg−1. The effect of biochar application rate on phyto-availability of cadmium, copper, and nickel concentrations varied with the background soil value and soil pH. For all three types of soil, the phyto-availability of lead, chromium, and arsenic decreased significantly with increasing biochar rates. In conclusion, it is important to carefully consider soil type and pH when utilizing biochar as a soil amendment to maximize its efficiency.

Revealing the Dual Role of Ammonia in the Hydroxide Co-Precipitation Synthesis of Cobalt-Free Nickel-Rich LiNi0.9Mn0.05Al0.05O2 (NMA955) Cathode Materials for Lithium-Ion Batteries.

Nickel-rich cobalt-free LiNi0.9Mn0.05Al0.05O2 (NMA955) is considered a promising cathode material to address the scarcity and soaring cost of cobalt. Particle size and elemental composition significantly impact the electrochemical performance of NMA955 cathodes. However, differences in precipitation rates among metal ions coveys a challenge in obtaining cathode materials with the desired particle size and composition via hydroxide co-precipitation synthesis. Utilizing complexing agents like ammonia offers an effective strategy to tackle these issues. Here, we investigate the optimal ammonia concentration to achieve moderate particle size and precise material composition. Although ammonia only forms complex coordination with transition metals, its concentration also affects the final product's precipitation and composition, including aluminum. This study shows that ammonia serves a dual function in NMA synthesis via hydroxide co-precipitation, i. e., regulating particle size and adjusting elemental composition. It was found that an ammonia concentration of 1.2 M achieved optimal particle size and composition, resulting in superior electrochemical performance. NMA955 synthesized in 1.2 M ammonia demonstrated a high specific capacity of 188.12 mAh g-1 at 0.1 C, retained 71.16 % of its capacity after 200 cycles at 0.2 C, and delivered 110.30 mAh g-1 at 5 C. These results suggest that tuning ammonia concentration is crucial for producing high-performance cathode materials.

The effect of microclimate on pig weight gain evaluated with multisensor

In this study, a multisensory system was built to evaluate the effect of the temperature, humidity, the concentration of carbon dioxide and ammonia on pig weight gain. During the experiment, RGB-based image analysis provided body weight information of 22 pigs over a three-month period. In the experiment, two cameras were set to obtain pictures, and the resulting data showed high correlation. Pearson’s and Spearman’s correlation was calculated between the body weight and the monitored environmental parameters. Results showed that temperature negatively correlates with the body weight, while CO2 and NH3 have a positive correlation. In this study, humidity, random effect, and changes in temperature had slightly negative but not significant correlation with body weight gain. Multiple linear regression showed that temperature and humidity had a significant effect on the body weight gain of the pigs, while the effect of the NH3 was also noticeable. Our results proved that image-analysis-based weight evaluation is a powerful tool in precision livestock farming and that environmental conditions have a significant effect on pigs’ production.

Accounting for the role of the gastro-intestinal tract in the ammonia and urea-N dynamics of freshwater rainbow trout on long-term satiation feeding.

The contribution of the gut to the ingestion, production, absorption, and excretion of the extra ammonia and urea-N associated with feeding ("exogenous" fraction) has received limited prior attention. Analysis of commercial pellet food revealed appreciable concentrations of ammonia and urea-N. Long term satiation-feeding increased whole trout ammonia and urea-N excretion rates by 2.5-fold above fasting levels. Blood was sampled from the dorsal aorta, posterior, mid, and anterior sub-intestinal veins, as well as the hepatic portal vein in situ. Ammonia, urea-N, and fluid flux rates were measured in vitro using novel gut sac preparations filled with native chyme. The sacs maintained the extreme physico-chemical conditions of the lumen seen in vivo. Overall, these results confirmed our hypothesis that the stomach and anterior intestine+pyloric caecae regions play important roles in ammonia and urea-N production and/or absorption. There was a very high rate of urea-N production in the anterior intestine+pyloric caecae, whereas the posterior intestine dominated for ammonia synthesis. The stomach was the major site of ammonia absorption, and the anterior intestine+pyloric caecae region dominated for urea-N absorption. Model calculations indicated that >50% of the exogenous ammonia and urea-N excretion associated with satiation-feeding was produced in the anaerobic gut. This challenges standard metabolic theory used in fuel use calculations. The novel gut sac preparations gained fluid during incubation, especially in the anterior intestine+pyloric caecae, due to marked hyperosmolality in the chyme. Thus, satiation-feeding with commercial pellets is beneficial to the water balance of freshwater trout.

Effects of Different Molasses Levels and Slow-Release Urea Combinations on Growth Performance, Serum Biochemistry, Rumen Fermentation, and Microflora of Holstein Fattening Bulls

The aim of this study was to investigate the effects of different combinations of molasses levels and slow-release urea on Holstein fattening bulls. Sixty Holstein fattening bulls of a similar age, weight, and health status were randomly divided into four groups of fifteen Holstein fattening bulls each. All of the treatments were as follows: (1) basic diet group (CON); (2) 2% molasses slow-release urea group (LMU); (3) 4% molasses slow-release urea group (MMU); and (4) 6% molasses slow-release urea group (HMU). The results of the study showed that the MMU had an outstanding performance, with a 13.3% increase in average daily weight gain compared with the control group, a significant decrease in feed conversion ratio (p &lt; 0.05), and a significant increase in apparent digestibility of crude protein (p &lt; 0.05). In terms of serum biochemical indices, blood ammonia and alanine aminotransferase (ALT) concentrations were significantly higher in the MMU than in the CON (p &lt; 0.05). The rumen pH of all treatment groups was lower than that of the CON (p &lt; 0.05), whereas the concentrations of microbial crude protein (MCP), as well as acetic acid, propionic acid, and total volatile fatty acids (TVFA) were significantly higher in both the MMU and HMU (p &lt; 0.05). The dominant phyla in each group were Bacteroidetes, Firmicutes, and Patescibacteria, and the relative abundance of Bacteroidetes in the MMU increased by 5.47% compared with that in the CON. In the MMU, Prevotellaceae, Lachnospiraceae, and Ruminococcaceae increased by 9.03%, 0.67%, and 3.43%, respectively, compared with the CON. The economic benefit analysis showed that the daily feeding cost of fattened cattle in the MMU was reduced by RMB 1.62 yuan, and the daily farming benefit of each cow was increased by RMB 7.19 yuan. In conclusion, the MMU was effective in improving the growth performance of fattening cows, optimizing rumen fermentation, reducing cost, and increasing profit, which is a nutritional strategy with great application value.

Next-Generation Potentiometric Sensors: A Review of Flexible and Wearable Technologies.

In recent years, the field of wearable sensors has undergone significant evolution, emerging as a pivotal topic of research due to the capacity of such sensors to gather physiological data during various human activities. Transitioning from basic fitness trackers, these sensors are continuously being improved, with the ultimate objective to make compact, sophisticated, highly integrated, and adaptable multi-functional devices that seamlessly connect to clothing or the body, and continuously monitor bodily signals without impeding the wearer's comfort or well-being. Potentiometric sensors, leveraging a range of different solid contact materials, have emerged as a preferred choice for wearable chemical or biological sensors. Nanomaterials play a pivotal role, offering unique properties, such as high conductivity and surface-to-volume ratios. This article provides a review of recent advancements in wearable potentiometric sensors utilizing various solid contacts, with a particular emphasis on nanomaterials. These sensors are employed for precise ion concentration determinations, notably sodium, potassium, calcium, magnesium, ammonium, and chloride, in human biological fluids. This review highlights two primary applications, that is, (1) the enhancement of athletic performance by continuous monitoring of ion levels in sweat to gauge the athlete's health status, and (2) the facilitation of clinical diagnosis and preventive healthcare by monitoring the health status of patients, in particular to detect early signs of dehydration, fatigue, and muscle spasms.

Transcriptional activity of ammonia oxidisers in response to soil temperature, moisture and nitrogen amendment

The contrasting response of AOA, AOB, and comammox Nitrospira amoA transcript abundance to temperature, moisture, and nitrogen was investigated using soil microcosms. The moisture, temperature, and nitrogen treatments were selected to represent conditions typically found in a New Zealand (NZ) dairy farm. AOB dominated all synthetic urine treated soils. Peak AOB amoA transcript abundance was positively correlated with estimated soil ammonia availability. While AOB gDNA abundance and nitrification rate trends were similar. AOA were strongly influenced by soil temperature. At 20°C, AOA amoA peak transcript abundance averaged over 1 order of magnitude higher than at 8°C. Within the AOA community a member of the Nitrosocosmicus clade was positively correlated with ammonium and estimated ammonia concentrations. The presence and relative increase of an AOA community member in a high nitrogen environment poses an interesting contrast to current scientific opinion in NZ. Comammox Nitrospira abundance showed no correlation with soil moisture. This suggests that previously found associations are more complex than originally thought. Further research is required to determine the drivers of comammox Nitrospira abundance in a high moisture environment. Overall, these results indicate that AOB are the main drivers of nitrification in New Zealand dairy farm soils.

Utilization of the aqueous phase of the hydrothermal liquefaction process as a substrate for microalgae cultivation

The article presents the culturing of nine microalgae strains from the IPPAS collection of IFR RAS using components of the aqueous phase of the excessive activated sludge hydrothermal revitalization process as a substrate. In order to select the most promising cultures, their growth characteristics and efficient removal of NH4+ ions, PO43- and organic compounds were studied. All the studied cultures are shown to be able to utilize components of the aqueous phase as a nutrient substrate. The highest specific growth rate of 0.92 day-1 was observed in the strain Chlorella sp. IPPAS C-1210. However, the Parachlorella kessleri IPPAS C-9 and Chlorella minutissima IPPAS C-123 strains were also promising in terms of their efficiency of pollutant removal from the medium: efficiency of ammonium nitrogen assimilation was 78 and 81%, while phosphate ion assimilation was 89 and 91%, respectively. The biomass composition of C-9 and C-123 cultures was investigated, mainly consisting of polysaccharides – at 41 and 44% – and proteins – at 31 and 25% of the total mass, respectively. A high degree of neutralization of the medium was additionally achieved as a result of consecutive two-stage purification of the aqueous phase of the process of hydrothermal revitalization of excessive activated sludge with the use of microorganisms-destructors (Paenarthrobacter nicotinovorans and Comamonas testosteroni) and the studied microalgae cultures. During 17 days of the purification process, the concentration of ammonium ions decreased from 289.8±14.9 to 51.1±2.2 mg/dm3, phosphates from 116.3±8.1 to 11.3 mg/dm3; the overall efficiency of the process of pollutants removal from the aqueous phase was up to 90%.

Integrated learning‐based estimation and nonlinear predictive control of an ammonia synthesis reactor

AbstractThis paper presents an advanced machine learning‐based framework designed for predictive modeling, state estimation, and feedback control of ammonia synthesis reactor dynamics. A high‐fidelity two‐dimensional multiphysics model is employed to generate a comprehensive dataset that captures variable dynamics under various operational conditions. Surrogate long short‐term memory neural networks are trained to enable real‐time predictions and model‐based control. Additionally, a feedforward neural network is developed to estimate the outlet ammonia concentration and hotspot temperature using spatially distributed temperature readings, thereby addressing the challenges associated with real‐time concentration and maximum temperature measurements. The machine learning‐based predictive modeling and state estimation methods are integrated into a model predictive control architecture to regulate ammonia synthesis. Simulation results demonstrate that the machine learning surrogates accurately represent the nonlinear process dynamics with minimal discrepancy while reducing optimization costs compared to the high‐fidelity model, ensuring adaptability and effective guidance of the reactor to desired set points.

β-Catenin/c-Myc Axis Modulates Autophagy Response to Different Ammonia Concentrations.

Ammonia a by-product of nitrogen containing molecules is detoxified by liver into non-toxic urea and glutamine. Impaired ammonia detoxification leads to hyperammonemia. Ammonia has a dual role on autophagy, it acts as inducer at low concentrations and as inhibitor at high concentrations. However, little is known about the mechanisms responsible for this switch. Wnt/β-catenin signalling is emerging for its role in the regulation of ammonia metabolizing enzymes and autophagosome synthesis through c-Myc. Here, using Huh7 cell line, we show a modulation in c-Myc expression under different ammonia concentrations. An increase in c-Myc expression and in its transcriptional regulator β-catenin was detected at low concentrations of ammonia, when autophagy is active, whereas these modifications were lost under high ammonia concentrations. These observations were also recapitulated in the livers of spf-ash mice, a model of constitutive hyperammonaemia due to deficiency in ornithine transcarbamylase enzyme. Moreover, c-Myc-mediated activation of autophagy plays a cytoprotective role in cells under ammonia stress conditions as confirmed through the pharmacological inhibition of c-Myc in Huh7 cells treated with low ammonia concentrations. In conclusion, the unravelled role of c-Myc in modulating ammonia induced autophagy opens new landscapes for the development of novel strategies for the treatment of hyperammonemia.

Numerical Simulation of Static Ammonia Mixer in Denox Unit of Flue Gas Purification Plant

The modeling of a mixer used for mixing ammonia and flue gasses is considered. Simulations were performed using Flow Vision 3.14 (TESIS LLC). As a result of the simulation, the distribution of concentrations along the mixer length was obtained at 50%, 65%, 85%, and full flue gas loading. It was found that operations at 100% and 85% gas loads are accompanied by an acceptable distribution of ammonia in the mixer volume (Cov = 0.05). The development and creation of an experimental model in real production was carried out according to the results of the numerical simulation. The simulation results were compared with experimental data on the speed and concentration of ammonia in the control section. The discrepancy, in general, did not exceed 15%. The developed mixer corresponds to modern developments in terms of mixing quality but is simpler in design and more compact.

Enhancement of FK520 production in Streptomyces hygroscopicus var. ascomyceticus ATCC 14891 by overexpressing the regulatory gene fkbR2.

Ascomycin (FK520) is a 23-membered macrolide antibiotic primarily produced by the Streptomyces hygroscopicus var. ascomyceticus. Structurally similar to tacrolimus and rapamycin, it serves as an effective immunosuppressant widely used in the treatment of rejection reactions after organ transplantation and certain autoimmune diseases. Currently, FK520 is mainly produced through microbial fermentation, but its yield remains low. Since the gene fkbR2 is a regulatory gene within the FK520 biosynthesis gene cluster that has not been studied, this paper focuses on the overexpression of the gene fkbR2 in Streptomyces hygroscopicus var. ascomyceticus ATCC 14891 (WT). By constructing a strain with overexpressed fkbR2 gene, we initially obtained a high-yield strain R2-17 through shake flask fermentation, with a 28% increase in yield compared to WT. In the process of further improving the stability of the high-yield strain, this paper defines two indices: high-yield index and stability index. After two consecutive rounds of natural breeding, strain R2-17 achieved a high-yield index of 100% and a stability index of 80%. Finally, the high-yield strain R2-17-3-10 was successfully screened, and the yield was increased by 34% compared with the strain WT, reaching 686.47mg/L. A comparative analysis between the high-yield strain R2-17-3-10 and the original strain WT revealed differences in fermentation process parameters such as FK520 synthesis rate, pH, bacterial growth, glycerol consumption rate, ammonia nitrogen level, and ammonium ion concentration. In addition, the transcription levels of genes involved in the synthesis of precursors 4,5-dihydroxycyclohex-1-enecarboxylic acid (fkbO), ethylmalonyl-CoA (fkbE, fkbU, fkbS), and pipecolic acid (fkbL), as well as pathway-specific regulatory genes (fkbN, fkbR1), were significantly increased at different time points in the high-yield strain R2-17-3-10. EMSAs analysis showed that the FkbR2 protein could not bind to the promoter region of above genes. This suggests that the gene fkbR2 may enhance the supply of FK520 synthetic precursors by indirectly regulating the transcription levels of these genes, thereby promoting an increase in FK520 production. These results demonstrate that modifying genes within the biosynthetic gene clusters of natural products can be successfully applied to increase the yields of industrially and clinically important compounds. However, it is found that fkbR2 gene is a regulatory gene that has not been fully studied, and it is worth further studying its regulatory mechanism.

Municipal anaerobic filter effluent treatment using advanced oxidation processes for potential use in unrestricted crop production

To meet wastewater treatment quality standards for reuse, integrating advanced oxidation processes (AOPs) with Decentralized Wastewater Treatment Systems (DEWATS) is promising. This study aimed to optimize AOPs (ozonolysis, UV photolysis, TiO2 photocatalysis) for polishing anaerobic filter (AF) effluent from DEWATS, as an alternative to constructed wetlands. Metrics included pathogen reduction efficiency, post-disinfection regrowth, and effects on physical parameters (pH, EC, turbidity), organic matter (soluble COD, BOD, DOC, humic), and nutrient concentration (ammonium, nitrates, ortho-P). Ozonolysis and TiO2 photocatalysis achieved a 6.4-log pathogen reduction, while UV photolysis achieved a 6-log. No pathogen regrowth occurred with ozonolysis, but TiO2 photocatalysis showed E. coli and Total coliforms regrowth of 2.5-log and 2.7-log, respectively. UV photolysis showed 0.5-log and 2.2-log regrowth for E. coli and Total coliforms, respectively. TiO2 photocatalysis significantly reduced BOD, soluble COD, humic substances, ortho-P, turbidity, and nitrates, while increasing pH, EC, ammonium, and DOC. Ozonolysis significantly lowered BOD, soluble COD, humics, and turbidity, but increased ortho-P, nitrates, pH, EC, ammonium, and DOC. UV-photolysis showed marginal reductions in BOD, nitrates, and turbidity, with increased EC, pH, ammonium, DOC, ortho-P, and humic levels. Ozonolysis emerged as the best AOP, demonstrating efficient effluent treatment with no pathogen regrowth.