Ammonia Concentration Research Articles

PSXIII-15 Functional and molecular responses of cultured bovine granulosa cells to increased concentrations of ammonia in vitro

Abstract Animals in agricultural production settings are often fed high levels of protein to maximize their performance (e.g., growth, lactation). However, animals that consume diets that are excessively high in protein often suffer from reduced reproductive efficiency. The causes behind this decreased reproductive performance are not fully understood. It is well established that increased dietary protein leads to increased concentrations of both ammonia and urea in the blood and other fluids of the body. These increased metabolite concentrations may be a possible link to the decline in reproductive success. The goal of this study is to characterize the molecular response of cultured bovine granulosa cells to various levels of ammonia. Our hypothesis is that increasing concentrations of ammonia in the culture medium will be associated with greater concentrations of intracellular reactive oxygen species (ROS), changes in gene expression, and reduced steroidogenesis, particularly 17-β estradiol production. The cells used for these experiments were harvested from abattoir-derived bovine ovaries. After the cells were established in culture for 48 h, they were exposed to media containing 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, 6 mM, or 7 mM ammonia for 24 h. The cells were then evaluated for viability, proliferation rates, gene expression, oxidative stress, and 17-β estradiol production. There were significant changes in proliferation between the control and the 6 mM and 7 mM ammonia groups (2.71 vs. 1.96 vs 1.92 population doublings per 72 h culture period, respectively; P < 0.05). Cell viability was also statistically different between control (97.8% ± 0.3%) and 7 mM ammonia-treated (93.3% ± 1.2%) cells (P < 0.05). Ten out of 25 genes involved in steroidogenesis, redox reactions, or solute transport from our analysis showed significant changes (P < 0.05) and at least ± 50% difference in relative transcript abundance in at least one of the pairwise comparisons between treatment groups, but no obvious, consistent trends regarding dose-dependent effects of ammonia on granulosa cell gene expression were noted. There were no significant changes in 17-β estradiol production (P > 0.05) or ROS (P > 0.05) in response to ammonia treatment. The concentrations of ammonia that induced the changes noted are above normal physiological concentrations but are achievable in vivo depending on the amounts of protein in the diet of an animal. This study shows that granulosa cells are in some ways impacted by varying concentrations of ammonia. Future studies will reveal if and how these and other changes to granulosa cells under similar conditions might impact the ovarian follicular microenvironment, subsequent oocyte maturation and embryo development, and reproductive performance in general.

Affordable droplet-based flow analyzer with peristaltic micro-pumps for fluorescent ammonium sensing

An affordable droplet-based flow analyzer incorporating peristaltic micro-pumps has been developed for fluorescent ammonium sensing. The cost-effective peristaltic micro-pumps, modified using 3D-printing techniques, feature a 3D-printed pump base integrated with a Hall sensor to monitor the rotation of the pump motor. This setup generates a pulse flow instead of a continuous flow, delivering specific volumes (typically between 3 to 4 μL) of solution with each rotation. By using separate pumps to deliver the aqueous and oil phases, these phases merge to form a droplet flowing stream. The relative standard deviation (RSD) values for droplet volumes range from 3.97 % to 5.99 % (n=50) across different pumps. The analyzer utilizes a reaction between ammonium, ortho-phthalaldehyde, and sulfite to produce a fluorescent derivative, allowing for sensitive detection of low ammonium concentrations. A custom light-emitting diode (LED)-based fluorescence detector has been fabricated using 3D printing, ensuring cost-effective production. The analyzer provides a limit of detection of 0.02 μM (3σ) and an RSD of 0.15 % (n=10, 1 μM ammonium). This analyzer offers several practical advantages, including reduced reagent consumption and the potential for further development in distributed on-site analysis. The use of 3D printing facilitates rapid prototyping and customization, making the system adaptable to various analytical applications.

287 Effects of crude glycerin supplementation of beef cattle grazing wheat pasture on forage intake and characteristics of rumen fermentation

Abstract Crude glycerin (CG), mainly composed of glycerin, is a by-product of biodiesel production. Glycerin can be utilized as a substrate of gluconeogenesis by either rapid fermentation to propionate in the rumen or can be directly absorbed through the rumen epithelial wall, resulting in the conversion to glucose in the liver. Therefore, CG supplementation may increase the energy intake of cattle grazing wheat pasture. Ruminally cannulated Angus-crossbred cows [n = 9; 564.4 ±101.6 kg initial body weight (BW)] grazing wheat pasture were utilized in a split-plot design with the objective of evaluating the effects of CG supplementation and forage maturity on forage intake and rumen fermentation characteristics. Treatment was the main plot, and stage of forage maturity was the subplot. Treatments were unsupplemented control (CON) and crude glycerin supplementation (SUP; 37.2% glycerin, DM basis) dosed at 0.11% BW (DM basis). Supplementation levels correspond to 5% of the diet, assuming forage intake of 2.2% of BW on a DM basis. The stages of wheat maturity pasture were March (MAR; vegetative stage) and April (APR; early reproductive stage). Cows grazed a single wheat pasture and were supplemented directly through the rumen cannula twice daily at 0700 and 1900 h. Forage intake in kg/d and as % of BW was greater (P = 0.04) for SUP than CON. Ruminal pH, ammonia, and VFA concentrations, as well as proportions of VFAs, were not affected by CG supplementation (P ≥ 0.34; Table 1). However, ruminal pH (5.77 and 5.99 ± 0.049) and ammonia concentration (0.67 and 3.37 ± 0.307 mM) were greater, while total VFA concentration (136.3 and 110.8 ± 5.23 mM) was less (P = 0.01) for APR compared with MAR. Acetate, propionate, and butyrate molar proportions, as well as acetate: propionate ratio, were not affected (P ≥ 0.27) by the stage of wheat pasture maturity. Results indicate that crude glycerin used as an ingredient in supplementation strategies for cattle grazing wheat pasture may increase cattle energy intake without negatively affecting forage intake and ruminal fermentation.

476 Induced hindgut acidosis in sheep affected gut permeability and ruminal fermentation

Abstract Leaky gut may be caused by acidotic conditions in the hindgut and lead to systemic inflammation and negative effects on the gastrointestinal tract. The objective was to determine the effects of induced hindgut acidosis in sheep on cecal pH, ruminal fermentation, and gut permeability. Ruminally and cecally cannulated ewes [n = 11; body weight (BW) = 49 ± 4 kg] were assigned to one of two treatments: control (CON; n = 5) or induced hindgut acidosis (HGA; n = 6). To induce hindgut acidosis, 3 g wheat starch/kg BW per 24 h was continuously infused via the cecal cannula for 4 d. Control ewes received a constant infusion of deionized water. The diet contained 40% grass hay pellets, 35% whole shelled corn, 15% dried distillers grains, and 10% alfalfa cubes. Chromium EDTA was dosed once daily via the cecal cannula as a marker of gut permeability. Rumen, cecal, and fecal samples were collected to determine pH and volatile fatty acids (VFA). Rumen fluid was collected on d 4 for an ex vivo fermentation. Flasks were incubated for 24 h to determine pH, VFA, ammonia and in vitro dry matter digestibility. Tissue samples from the ileum, cecum, and colon were mounted in Ussing chambers to measure transepithelial electrical resistance (TEER). There was a treatment × time effect (P = 0.05) for cecal pH with HGA ewes having lesser cecal pH after d 1. By d 4, cecal pH had declined to 5.07 for HGA ewes compared with CON ewes which remained above 6.40 throughout the experiment. A treatment × time interaction was also observed (P < 0.01) for fecal pH and followed the same trend as cecal pH. Rumen pH was not affected (P = 0.87) by the interaction of treatment and time but was affected (P < 0.01) by treatment as ewes on the HGA treatment had a lesser rumen pH than CON ewes. Control ewes had lesser ruminal VFA and ammonia concentrations than HGA ewes (P < 0.01). Urinary Cr recovery was not affected by the interaction of treatment and time, or treatment (P ≥ 0.13). In vitro dry matter disappearance was not affected by cecal infusion treatment (P = 0.60). There was no effect (P = 0.78) of treatment on ex vivo pH. There were no effects (P ≥ 0.11) of treatment, time, or their interaction on ex vivo ammonia or total VFA concentration. In cecal tissue, TEER tended (P = 0.09) to be greater in CON ewes than HGA ewes. In contrast, TEER was not different (P ≥ 0.83) in ileal or colonic tissues between treatments. Induced hindgut acidosis in sheep altered rumen fermentation and tended to increase ex vivo measures of cecal permeability, but did not affect ex vivo rumen fermentation.

402 The effect of supplemental protein degradability and frequency of supplementation on nitrogen metabolism of beef cattle consuming low-quality forage

Abstract Rumen degradable protein (RDP) is required for cattle consuming low-quality forage to ensure adequate fiber digestion. However, in situations where cattle are not supplemented daily, supplementing RDP could overwhelm the nitrogen recycling mechanisms, leading to increased nitrogen excretion. The objective of this experiment was to determine the effect of rumen degradability and frequency of supplemental protein in beef cattle consuming low-quality forage. Treatments were arranged in a 2 × 2 factorial with protein degradability (68.5% or 32.8% RDP) and supplementation frequency (daily or biweekly) as the two factors. Ruminally cannulated Angus steers [n = 8; body weight (BW) = 328 ± 12.2 kg] were used in a Latin rectangle. The low RDP treatment was composed of 50% soybean hulls and 50% corn gluten meal (40.3% CP; 32.8% RDP), and the high RDP treatment consisted of 45.4% soybean hulls, 41.4% soybean meal, 4.1% urea, and 9.1% molasses (40% CP; 68.5% RDP). The biweekly steers were supplemented on d 0, 4, 7, 11, 14, 18, and 21 of each period. Steers were given ad libitum access to low-quality (7.4% CP) native grass hay. Daily blood samples were collected from d 14 to 17 at 0630 h and d 21 at -2, 3, and 7 h relative to supplementation. Rumen fluid samples were collected every 4 h on d 18 to 21. Daily NEFA concentrations decreased (P < 0.001) post-supplementation in the biweekly supplemented steers and then returned to baseline values, while the daily supplemented steers had no change. Hourly NEFA concentrations in steers supplemented with high RDP biweekly increased from 2 h pre-supplementation to 3 h post-supplementation (P < 0.001), then decreased at 7 h post-supplementation back to pre-supplementation concentrations. Plasma urea nitrogen (PUN) increased in biweekly high RDP supplemented steers 1 d after supplementation (P < 0.001) and decreased from d 15 to d 17. PUN concentrations increased from 2 h pre-supplementation through 7 h post-supplementation in both high RDP treatments, while low RDP treatments did not change (P < 0.001). Rumen fluid lactate and ammonia concentrations rapidly increased in the biweekly high RDP-supplemented steers in response to each supplementation (P < 0.001). There were spikes in ammonia concentrations for the daily high RDP treatment post-supplementation; however, they were smaller in magnitude compared with the biweekly high RDP. The low RDP treatments remained steady across all hours of ammonia sampling, where daily and biweekly supplemented steers decreased slightly in the time points following supplementation and then gradually increased. Rumen pH displayed drastic changes in the biweekly high RDP-supplemented group with values ranging from 6.99 to 5.97 (P < 0.001), but the low RDP treatments remained consistent. Supplementing biweekly with high RDP resulted in fluctuations in metabolites not observed in the other treatments, which could reduce forage utilization and increase nitrogen excretion.

Comprehensive protection against ammonia by Cu2+ modified activated carbon

An innovative “material-component-whole” evaluation model was used to assess the overall protective performance of gas masks against ammonia. Coconut shell-based carbon (AC-S), coconut shell-impregnated carbon (ACCu-S), coal-based carbon (AC-C), and coal-impregnated carbon (ACCu-C) were chosen as the adsorbents for this study. The physicochemical characteristics of the activated carbon samples were analyzed through SEM, BET, FT-IR, EA, XPS and XRD tests. This research delves into the breakthrough curves of ammonia gas by the activated carbon and canisters under varying concentrations of ammonia, ambient temperatures, airflow velocities, and relative humidity, also exploring the breakthrough curves of ammonia gas by gas masks under different ammonia concentrations and airflow patterns while considering both dynamic and static adsorption of activated carbon. The empirical results show that increased levels of ammonia concentration, ambient temperature, and airflow velocities lead to decreased protection duration of activated carbon and canisters. Conversely, an elevation in the relative humidity within the ammonia gas stream results in an expansion of the protection time. This study found a linear correlation between the protection time of S and C canisters and the corresponding protection time of the impregnated carbon. Lastly, the protective time of gas masks in sinusoidal airflow mode is highlighted as having a more significant impact.

33 Beyond bacteria: Impact of live yeast as a probiotic on the intestinal health of dogs

Abstract Inactivated yeast and yeast-based products are commonly used in pet food to improve palatability, contribute to dietary protein content, and improve gastrointestinal functionality. However, the use of viable yeast Saccharomyces as a probiotic may contribute to additional beneficial effects on dogs and cats. Considering that, in this presentation, we will focus on the use of viable yeast as a probiotic for dogs. A study conducted at the Federal University of Parana, Brazil, observed that Beagle dogs supplemented with a probiotic yeast presented reduced fecal concentrations of total biogenic amines, ammonia, and aromatic compounds and greater fecal concentrations of butyrate. The supplemented dogs also presented an improvement in dysbiosis index, a greater abundance of Bifidobacterium and Turicibacter, and a reduced abundance of Escherichia coli in feces. In addition, control group dogs presented upregulation in microbial genes related to virulence factors (such as lipopolysaccharide export system), antibiotic resistance, and osmotic stress, compared with the probiotic group. These results may indicate a possible protective effect of the yeast probiotic against potential pathogenic bacteria in the gut. The mechanisms by which yeast probiotics may contribute to gastrointestinal functionality in dogs and cats are not fully elucidated. However, they are usually attributed to the stimulation of brush edge disaccharidases; competition for adhesion sites against potential pathogens; stimulation of nonspecific immunity; neutralization of toxins; and direct effect against potentially pathogenic microorganisms. Many of these mechanisms are influenced directly by yeast cell wall components, such as mannans and beta-glucans. One of the main mechanisms of action of mannans is the elimination of bacteria with pathogenic potential that present type-1 fimbriae, such as some strains of E. coli and Salmonella, preventing their adhesion and colonization to the host mucosa. This may also contribute to the establishment of beneficial bacteria in the gut. We can conclude that viable yeast Saccharomyces as a probiotic may have promising beneficial effects on intestinal functionality of dogs.

Pilot-scale investigation of an advanced biofloc technology for treating Pacific white shrimp effluent: Performance and insight mechanisms

Biofloc technology (BFT) is extensively used in the treatment of water quality in intensive shrimp aquaculture systems. However, the rapid accumulation of biofloc in middle-to-late culture stages poses challenges for system management, impacting the economic yield of aquaculture operations. To address this issue, an advanced biofloc system (A-BS) that integrates a moving bed biofilm reactor (MBBR) with BFT was constructed, and the biofloc system (BS) was used as a control group. During a 100-day pilot-scale operation, the A-BS group effectively regulated water quality and enhanced the growth rate of Pacific white shrimp (Litopenaeus vannamei). In the A-BS group, the average concentrations of ammonia, nitrite, chemical oxygen demand, and mixed liquor suspended solids were substantially reduced compared to those in the BS group, measuring 0.19, 0.55, 36.36, and 229 mg/L, respectively, across the middle-to-late culture stages. Notably, the final stocking density and survival rate of shrimp in the A-BS group, reached 7.04 kg/m3 and 81.22 %, surpassing those in the BFT group. Furthermore, microbial community and functional gene analyses revealed more in-depth insights into the related mechanisms. Bacterial abundance and diversity, as well as the presence of denitrification genes such as Unclassified_f_Rhodobacteraceae and Paracoccus, were markedly higher in the A-BS group than in the BS group. The integration of MBBR into A-BS significantly increased the abundance of amoA and nirK genes, which are crucial for water quality stability during later culture stages. This proof-of-concept investigation confirms that the MBBR–BFT coupling process in A-BS holds promise for advancing sustainable aquaculture practice and provides strategic guidance for the modernization of the industry.

Feasibility of riverbank filtration in Vietnam

Riverbank filtration (RBF) could contribute to meeting the growing demand for drinking water in Vietnam. This study investigates the feasibility of implementing RBF in different regions of Vietnam, with a focus on the Red River Delta (RRD) and Binh Dinh (a province in central Vietnam). Although Vietnam’s extensive river network and shallow aquifers generally provide favorable hydrogeological conditions for RBF, regional variations in hydrogeology introduce specific challenges. In the RRD, complex hydrogeological settings, such as thick clay layers near the surface and low hydraulic conductivity in the Holocence aquifer, can limit the effectiveness of RBF in maximizing the portion of bank filtrate and improving water quality. In contrast, Binh Dinh generally presents more favorable conditions, with absence of clay layers on top and higher hydraulic conductivity leading to successful RBF implementation. Water quality issues such as high concentrations of ammonium, arsenic, and other pollutants persist in both RBF and groundwater in the RRD, requiring careful site-specific evaluations. The study also highlights that while surface water remains underutilized compared to groundwater, its use may be economically preferable in regions where groundwater quality is compromised. Lessons learned from the RRD and Binh Dinh can serve as good practice for RBF implementation in other parts of Vietnam. The findings indicate that while RBF holds significant promise for enhancing water supply in Vietnam, its application needs to be carefully tailored to local hydrogeological and water quality conditions.

516 Effects of increasing hybrid rye silage as a replacement for barley silage for growing beef heifers

Abstract The objective of these studies was to evaluate effects of increasing hybrid rye silage (HRS; harvested at boot stage in Study 1 and soft-dough in Study 2) inclusion as a replacement for barley silage (BS; harvested at soft-dough stage) on dry matter intake (DMI), ruminal fermentation, and growth performance of growing beef cattle. In Study 1, ruminally cannulated Hereford × Simmental heifers (n = 8) with an initial body weight (BW) of 519 ± 25.8 kg were used in a replicated 4 × 4 Latin square design with 28-d periods including 21 d of dietary adaptation and 7 d of data and sample collection to assess DMI and ruminal fermentation. Treatments included a control diet (DM basis) that contained 59.62% BS, 38.60% barley grain, and 1.78% of a vitamin and mineral supplement. Hybrid rye silage replaced 33, 67, and 100% of the BS on a DM basis. In Study 2, steers (n = 384; BW = 343 ± 20.2 kg) were stratified by BW and allocated to 32 pens in a randomized complete block design over 2 yr (4 pens/treatment/yr) to evaluate DMI, growth, and gain:feed (G:F). Steers were fed similar diets as Study 1 for 84 d in both years. In Study 1, increasing HRS linearly (P < 0.01) decreased DMI from 12.0 to 9.2 kg/d, and linearly increased (P = 0.02) water intake from 18.6 to 22.5 L/d. Increasing HRS linearly increased mean (P < 0.01) and minimum ruminal pH (P < 0.01). There was no effect of HRS inclusion on total short-chain fatty acid concentration (P = 0.46) in ruminal fluid, but the molar proportion of acetate linearly (P < 0.01) increased while propionate and butyrate linearly decreased (P < 0.01, and < 0.01, respectively) with increasing HRS inclusion. Moreover, increasing HRS inclusion linearly increased the molar proportions of isobutyrate and valerate (P = 0.06, and < 0.01, respectively) while caproate decreased linearly (P = 0.02). The ammonia-N concentration linearly increased with increasing HRS inclusion. In Study 2, DMI was 9.23, 9.10, 8.82, 8.08 kg/d (quadratic, P = 0.02) for diets containing 0, 33, 67, and 100% HRS, respectively. Likewise, ADG decreased (1.45, 1.36, 1.30, 1.08 kg/d; quadratic P < 0.01) as HRS inclusion increased and G:F ratio decreased linearly (P < 0.01) from 0.158 with 0% HRS to 0.134 g/kg when diets contained 100% HRS. Final BW was 462, 456, 450, and 432 kg when HRS was included at 0, 33, 67, and 100% of the silage, respectively (quadratic, P = 0.04). In conclusion, replacing BS with increasing proportions of HRS reduced DMI resulting in greater ruminal pH, altered molar proportions of individual SCFA, and reduced growth performance and G:F during the growing phase.

63 Impacts of protein supplementation frequency on animal performance, rumen fermentation and methane emission from growing beef cattle

Abstract Nutrient supplementation is one of largest expenditure in forage-based beef production systems, especially when forage quality is poor or limited. Decreasing supplementation frequency may have a role in improving sustainability by increasing animal performance and minimizing cost of labor and fuel. This study evaluated the impacts of protein supplementation frequency (canola meal pellet; CMP) on animal performance, rumen fermentation, and enteric methane production from beef cattle fed forage-based diet. A total of 60 crossbred backgrounding steers [body weight (BW) = 278 ± 10 kg) was randomly assigned to one of the three treatments (n = 20/treatment): i) control (no CMP supplementation), ii) control + everyday CMP supplementation (0.83 kg/d per steer), and iii) control + every other day supplementation of CMP. The study was comprised of 21 d of adaptation followed by three 21-d periods, with enteric methane measured for 7 d per period. Animals were fed grass hay-based diets once a day at 0800 h and remained on their respective diets throughout the 63-d study. Diets were formulated considering animal BW, feed nutrient density and environmental condition in accordance with the National Academies of Sciences, Engineering and Medicine. Each treatment group was assigned to a pen, with the cattle and diets rotated among pens weekly to allow the animals to access the GreenFeed system stationed in one of the pens for enteric methane measurement. For measurement of rumen fermentation products, three ruminally canulated steers (BW = 350 ± 20 kg) were allocated to the three treatments using a 3 x 3 Latin Square Design with 21-d periods so that one animal received all the treatments over the three experimental periods. Animals were adapted to the treatments for 17 d and rumen samples were collected between d 19 and 21 at 0700 h, 1000h, 1300 h, 1600 h and 1900 h. Data were analyzed using the Mixed procedure of SAS. Relative to the control treatment (9.9 kg/d), DM intake was 4 to 5% greater (P < 0.001) following CMP supplementation regardless of supplementation frequency. Similarly, average daily gain was greater (7 to 11%, P = 0.01) for CPM supplemented treatments as compared with control (1.04 kg/d) irrespective of supplantation frequency. Rumen fermentation was affected by treatments. Total VFA concentration was greater (P = 0.01) for the every other day supplementation of CMP as compared with control and daily supplementation treatments. Conversely, rumen ammonia concentration was not affected by treatments. The control group had greater acetate and reduced propionate molar proportions that resulted in a 5 to 6% greater acetate:propionate ratio (P < 0.01) as compared with the CMP supplemented groups. Enteric methane production (g/d) was greater for the daily CMP supplementation (P = 0.02) while yield (g/kg daily weight gain) was not affected by treatment. Our results indicated that reduction of protein supplementation frequency improved animal performance without negatively impacting rumen fermentation.

Rapid ambient pressure drying preparation of bulk ZrO2-SiO2 aerogels with high thermal stability

In this study, the sol-gel stage co-precursor method was used to hydrophobically modify the gel and increase the content of alkali catalyst in the gel, thereby reducing the capillary force generated during ambient pressure drying and enhancing the strength of the gel skeleton. This improvement makes the gel skeleton structure not easy to destroy during the rapid drying process, thus greatly reducing the preparation time of atmospheric pressure drying, which could be as short as 10 h. It is worth mentioning that this method does not require extensive use of modifiers and organic solvents, so it has low cost, high efficiency, and broad industrial production application prospects. The experimental results show that the DDS/ZSA aerogel exhibits the lowest thermal conductivity (0.035 W m−1 K−1) when the dilute ammonia content is 5 ml. However, it should be noted that too low or too high an amount of dilute ammonia will lead to a decrease in aerogel performance, so it needs to be controlled within the appropriate range. In addition, the prepared aerogel has excellent hydrophobic properties with a contact angle greater than 140° and excellent thermal stability at 1000 °C, which can be used in harsh, humid, and high-temperature environments.

Experimental investigation of the effects of aqueous ammonia and water mixtures on the efficiency and emissions of a compression ignition engine

In this study, different concentrations of aqueous ammonia and pure water were fumigated and aspirated into the cylinder from the engine intake manifold. Aqueous ammonia (NH4OH) with 5 %, 10 % and 15 % ammonia (NH3) concentration was used in the experiments. Both aqueous ammonia and pure water were converted into cold vapor using an ultrasonic evaporator and conveyed to the combustion chamber as fume. Experiments were carried out at a constant engine speed of 660 rpm. Torque values of 25 %, 50 %, and 100 % (386 Nm) were used in the experiments, respectively. As a result of the experiments, it was seen that as the ammonia percentage increased, the engine efficiency was negatively affected. At 100 % torque, when comparing the BTE value of pure diesel fuel with the BTE values of experiments with 5 %, 10 %, and 15 % ammonia addition, decreases of 0.09 %, 2.27 %, and 3.57 % were observed, respectively. In experiments conducted with pure water, although the thermal efficiency increased significantly as the torque ratio increased, it still could not reach the thermal efficiency of pure diesel fuel. On the other hand, it has been observed that water vapor improves NO and HC emissions. While the NOx value tends to increase with the increase in ammonia concentration at low and medium load values, the NOx value tends to decrease relatively as the ammonia concentration increases at 100 % torque value. The highest NOx emission value, 534 ppmvol, occurred in the experiments with 15 % NH4OH addition. It was observed that the NOx emission value of all experiments conducted with aqueous ammonia additive at 100 % torque was lower than pure diesel. In this study, the effects of NH4OH and H2O on engine performance and emissions were investigated.

Impacts of the East Asia monsoon on the PM2.5 acidity in Hanoi

This study investigates the acidity of particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) in Hanoi, the capital city of Vietnam, and its influencing factors by analyzing measured concentrations of water-soluble inorganic ions (WSIIs) in 107 24-h samples collected between June 2021 and February 2022. The average sulfate, nitrate, and ammonium concentrations were 5.79, 3.55, and 5.46 μg m−3, respectively. Among the samples, 83 exhibited alkaline aerosols characterized by elevated ammonium-to-sulfate molar concentration ratios (ASMCR) ranging from 2.3 to 9.6, while 24 showed acidic characteristics with ASMCR ranging from 0.5 to 2.5. By employing the Extended Aerosol Inorganic Model E-AIM III, with major WSIIs as the input parameters, the estimated aerosol acidity pH ranged from 8.6 to 10.9 for alkaline aerosols and below 4.5 for acidic aerosols. These variations in ASMCR and aerosol pH highlight the distinct acidic and alkaline aerosol source regions affecting Hanoi's PM2.5 by the monsoon air masses. The Potential Source Contribution Function (PSCF) maps of NH4+ and SO42− revealed the Northeast and Southeast monsoon upwind sources of acidic aerosols over China's Guangdong coastal region and Vietnam's offshore, respectively. Alkaline aerosols were observed during the Northeast and Southwest monsoons, with upwind sources originating in South China, Thailand, and Cambodia. The emergence of the ammonium-rich source areas in South China may be attributed to China's sustained emission control measures, targeting acidic SO2 and NOx emissions while leaving alkaline NH3 emissions largely unaffected. This research provided insights into the intricate relationships between regional emissions, long-range transport, and local meteorological-driven emissions, offering valuable guidance for effective air quality management in urban environments.

Urinary chloride excretion in critical illness and acute kidney injury: a paediatric hypothesis-generating cohort study post cardiopulmonary bypass surgery.

Renal chloride metabolism is currently poorly understood but may serve as both a diagnostic and a treatment approach for acute kidney injury. We investigated whether plasma chloride, ammonia and glutamine as well as urinary chloride, ammonium and glutamine concentrations may serve as markers for acute kidney injury in paediatric patients. We conducted a prospective observational trial in a tertiary care paediatric intensive care unit. Ninety-one patients after cardiopulmonary bypass surgery were enrolled. Plasma glutamine, creatinine, (serum) albumin, urinary electrolytes and glutamine were collected pre-cardiopulmonary bypass surgery, at paediatric intensive care unit admission, and at 6, 12, 24, 48 and 72 h after paediatric intensive care unit admission. The urinary strong ion difference was calculated. The median urinary chloride excretion decreased from 51 mmol/L pre-cardiopulmonary bypass to 25 mmol/L at paediatric intensive care unit admission, and increased from 24 h onwards. Patients with acute kidney injury had lower urinary chloride excretion than those without. The median urinary strong ion difference was 59 mmol/L pre-cardiopulmonary bypass, rose to 131 mmol/L at 24 h and fell to 20 mmol/L at 72 h. The plasma chloride rose from 105 mmol/L pre-cardiopulmonary bypass to a maximum of 109 mmol/L at 24 h. At 24 h the plasma chloride concentration was associated with the presence of acute kidney injury. There was no association between plasma or urinary amino acids and chloride excretion or kidney injury. In conclusion, renal chloride excretion decreased in all patients, although this decrease was more pronounced in patients with acute kidney injury. Our findings may reflect a response of the kidneys to critical illness, and acute kidney injury may make these changes more pronounced. Targeting chloride metabolism may offer treatment approaches to acute kidney injury.

Ultrahigh-purity ammonia recovery from synthetic coke wastewater via membrane contactor: Overcoming phenolic interference and assessing cost efficiency

Ammonia recovery from industrial wastewater using membrane contactor processes is emerging as a promising method owing to the diverse applications of ammonia. This study uniquely addressed ammonia recovery from coke plant wastewater, which is challenging due to the presence of numerous toxic and volatile phenolic compounds. Experiments were conducted using a synthetic coke plant effluent to assess the effects of various pH levels and temperatures on ammonia recovery. Specifically, the aim was to achieve high-purity ammonia recovery while minimizing the permeation of phenolic compounds. The results demonstrate that ammonia recovery in the membrane contactor processes is highly efficient, even in the presence of phenolic compounds. During temperature variations at 25 °C and 40 °C, the recovery of ammonia increased from 42.36% to 52.97% at pH 11. Additionally, increasing the pH of a feed solution from 7 to 12 significantly increased the ammonia content to 58.3%. At this pH, the recovered ammonia was of exceptional purity (>99%), with phenol, p-Cresol, and 2,4-xylenol present at negligible concentrations (0.001%, 0.002%, and 0.004%, respectively). This was attributed to the ionization of phenolic compounds at higher pH levels, which prevents their permeation through the hydrophobic membrane. The estimated cost analysis revealed that the membrane contactor process at pH 12 was approximately 1.41 times more cost-effective than conventional air-stripping processes over eight years of operating period (pH-12 membrane contactor: $19.79; pH-12 air stripping: $23.75). This study provides a detailed analysis of the optimal conditions for selective ammonia recovery from complex wastewater, highlighting both effective treatment and sustainable resource recovery and offering a superior alternative to traditional methods.

In-situ polarization modulation IRRAS investigation of ammonia electrooxidation on Pt-Ir and Pt-Ru nanoparticles prepared on engineered catalyst supports

The catalytic activity and surface reactivity of monometallic Pt and bimetallic Pt-Ir and Pt-Ru nanoparticles, supported on two distinct Engineered Catalyst Supports (ECSs), were investigated for the Ammonia Electrooxidation Reaction (AmER) in alkaline media. XRD measurements confirmed alloy formation between Pt-Ir and Pt-Ru nanoparticles, as indicated by the shift of the (111) reflection to higher 2θ values. Cyclic voltammetry, linear sweep voltammetry, and chronoamperometry experiments were conducted to assess the catalytic activity of the Pt, Pt-Ir, and Pt-Ru electrocatalysts. All bimetallic catalysts exhibited lower onset potentials compared to Pt. The differing Tafel slopes between Pt (74 mV dec⁻¹), Pt-Ir (152 mV dec⁻¹), and Pt-Ru (118–197 mV dec⁻¹) suggest that alloying Pt with Ir or Ru alters the reaction mechanisms. Furthermore, the bimetallic Pt-Ir and Pt-Ru catalysts demonstrated greater tolerance for concentrated ammonia solutions relative to Pt.In-situ Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) provided insights into the formation of N-H species, azide anions (N₃⁻), and N-O compounds. For the Pt-Ru catalyst, an additional peak around ∼3600 cm⁻¹ was observed, corresponding to OH⁻ species. The PM-IRRAS results align with the Gerischer–Mauerer mechanism, indicating that partially dehydrogenated ammonia adsorbates act as active intermediates in the oxidation of ammonia over Pt-Ir and Pt-Ru catalysts.

MODERN FEEDING REGIME FOR THE CONTROL OF AMMONIA GAS PRODUCTION FROM POULTRY LITTER IN BROILER PRODUCTION

The study was conducted to determine the effects of Rosemary leaf meal (RLM) and Sodium Bentonite (SB) on litter characteristics of broilers. A total of 180 day-old chicks of Cobb 500 strain of broilers were used for the study. The birds were randomly grouped and allocated to six (6) dietary treatments, which contained, T1(0g RLM+0g SB) and served as Control, T2(0g RLM+15g SB), T3(3g RLM+0g SB), T4(3g RLM+15g SB), T5(6g RLM+0g SB) and T6(6g RLM+15g SB), respectively, pe kilogramme of feed, with 30 birds per treatment. Each treatment was replicated 3 times with 10 birds per replicate in a 2*3 factorial arrangement in a completely randomized design (CRD). The experiment lasted for 8 weeks. At the end of the experimental period, litter samples were collected and analyzed according to treatments, to determine the pH, moisture and ammonia contents. The results showed that there were significant (p<0.05) decrease in pH level, from (7.75 to 7.07), and ammonia gas content (11.8 to 9.62ppm). The interaction effect of RLM and SB on litter characteristics at 8weeks of the experiment showed significant (p<0.05) decrease in ammonia (12.37 to 8.13ppm), pH level (7.80 to 6.23), and moisture content (16.47 to 13.73) in T4. It was concluded that, 15g SB and 3g RLM per kg feed improved litter characteristics by reducing ammonia gas production in the litter, and thus, recommended that 15g SB and 3g RLM should be used by farmers to improve litter characteristics in order to control odour in poultry houses.

Dietary supplementation of valine, isoleucine, and tryptophan may overcome the negative effects of excess leucine in diets for weanling pigs containing corn fermented protein

BackgroundDiets with high inclusion of corn co-products such as corn fermented protein (CFP) may contain excess Leu, which has a negative impact on feed intake and growth performance of pigs due to increased catabolism of Val and Ile and reduced availability of Trp in the brain for serotonin synthesis. However, we hypothesized that the negative effect of using CFP in diets for weanling pigs may be overcome if diets are fortified with crystalline sources of Val, Trp, and (or) Ile.MethodsThree hundred and twenty weanling pigs were randomly allotted to one of 10 dietary treatments in a completely randomized design, with 4 pigs per pen and 8 replicate pens per treatment. A corn-soybean meal diet and 2 basal diets based on corn and 10% CFP or corn and 20% CFP were formulated. Seven additional diets were formulated by fortifying the basal diet with 20% CFP with Ile, Trp, Val, Ile and Val, Ile and Trp, Trp and Val, or Ile, Trp and Val. A two-phase feeding program was used, with d 1 to 14 being phase 1 and d 15 to 28 being phase 2. Fecal scores were recorded every other day. Blood samples were collected on d 14 and 28 from one pig per pen. On d 14, fecal samples were collected from one pig per pen in 3 of the 10 treatments to determine volatile fatty acids, ammonium concentration, and microbial protein. These pigs were also euthanized and ileal tissue was collected.ResultsThere were no effects of dietary treatments on any of the parameters evaluated in phase 1. Inclusion of 10% or 20% CFP in diets reduced (P < 0.05) final body weight on d 28, and average daily gain (ADG) and average daily feed intake (ADFI) in phase 2 and for the entire experimental period. However, pigs fed the CFP diet supplemented with Val, Ile, and Trp had final body weight, ADFI, ADG and gain to feed ratio in phase 2 and for the entire experiment that was not different from pigs fed the control diet. Fecal scores in phase 2 were reduced (P < 0.05) if CFP was used.ConclusionsCorn fermented protein may be included by up to 20% in diets for weanling pigs without affecting growth performance, gut health, or hindgut fermentation, if diets are fortified with extra Val, Trp, and Ile. Inclusion of CFP also improved fecal consistency of pigs.

A dynamic model for predicting biomass and phycocyanin yields in Arthrospira (Spirulina) platensis: A guidance for effective batch cultivation

C-phycocyanin (C-PC) is a highly valuable bioproduct from the cyanobacterium Arthrospira platensis. A crucial factor affecting growth and C-PC production yield is nitrogen nutrients. In this work, an ODE-based dynamic model was constructed to simulate the effect of ammonium concentrations in a batch system on cyanobacterial growth and C-PC production. The model included dynamic regulation of the ammonium transporter and key enzymes involved in the nitrogen assimilation pathway. The prediction of C-PC production, cyanobacterial growth, and remaining ammonium concentration over 24 h strongly correlated with experimental data. Furthermore, the model was able to capture the response of genes involved in ammonium assimilation and C-PC production, as well as the primary metabolites. The dynamic interplay among ammonium, glutamine, and glutamate levels reflects the complexity of nitrogen metabolism in regulating the transcription of genes involved in ammonium uptake, assimilation, and C-PC synthesis and degradation, thus highlighting the cellular response to nitrogen stress. These findings provide a foundation for understanding these biological processes and offer a potential tool for further exploring the complex relationship between nitrogen availability and C-PC accumulation in A. platensis C1 using ammonium as a nitrogen source.