Search Results (6,889)

Plasma-assisted ammonia (NH₃) decomposition is a promising strategy for hydrogen production. However, reactor geometry remains a key factor limiting its hydrogen yield per energy input (${\mathrm{Y}}_{{\mathrm{H}}_2}$). This study systematically investigates H₂ production in outer-dielectric (OD), inner-dielectric (ID), and double-dielectric (DD) coaxial DBD reactors. The results show that the ammonia decomposition performance of OD- and ID-coaxial DBDs is significantly higher than that of the DD-coaxial DBD. OD- and ID-coaxial DBDs generate abundant micro-discharge pulses, enabling effective discharge energy deposition at lower peak voltages. Consequently, the reduced electric fields E/N are maintained within the optimal kinetic window for NH₃ dissociation and H₂ production. Moreover, by balancing residence time and energy density, the 8 cm length electrode achieves a peak ${\mathrm{Y}}_{{\mathrm{H}}_2}$ of 1.22–1.24 gH₂/kWh in the OD-coaxial DBD. For the ID-coaxial DBD, a 1 mm dielectric thickness yields a maximum capacitance of 86 pF, achieving a peak ${\mathrm{Y}}_{{\mathrm{H}}_2}$ of ~1.35 gH₂/kWh at the optimum E/N. In contrast, the DD-coaxial DBD exhibits the lowest ${\mathrm{Y}}_{{\mathrm{H}}_2}$ (≤0.82 gH₂/kWh) with minimal temperature rise. This is caused by the reduced current pulse numbers and the deviation of E/N from the optimal range with elevated operating voltages. This work provides guidance for the optimization of DBD reactors in plasma-assisted NH₃ decomposition for efficient H₂ production. Full article

As a carbon-free fuel, ammonia can substantially reduce the carbon footprint of internal combustion engines. However, its slow flame propagation speed and high ignition temperature present combustion challenges. A dual-fuel engine combining ammonia with diesel can effectively address these issues and enhance combustion performance. This study investigates the effects of diesel split ratio (DSR), start of diesel pre-injection (SODI-pre), and start of diesel main-injection (SODI-main). The results indicate that, compared to single diesel injection, segmented diesel injection significantly improves mixture distribution and reactivity, leading to enhanced flame propagation. With a pre-injection ratio of 10% and SODI-pre advanced to −62 °CA, the indicated thermal efficiency increases from 45.35% to 47.61%. Meanwhile, NH₃ emissions decrease from 1707 ppm to 689 ppm, and greenhouse gas N₂O concentration drops from 370 ppm to 251 ppm. Nevertheless, elevated NO_x emissions remain a significant challenge. Full article

Cardiac positron emission tomography (PET) has undergone substantial development in recent years, moving beyond conventional perfusion imaging toward a multiparametric and increasingly quantitative assessment of cardiovascular disease. This article provides a critical narrative overview of the recent cardiac PET literature, with particular emphasis on studies published over the last five years, and discusses both established tracers and emerging radiopharmaceuticals in contemporary cardiology. Among established applications, 18F-FDG remains relevant for myocardial viability assessment and selected inflammatory indications, although its prognostic and therapeutic implications are less uniform than earlier narratives suggested. For myocardial perfusion imaging, 13N-ammonia and 82Rb PET provide robust assessment of myocardial blood flow and myocardial flow reserve, but their clinical interpretation remains strongly influenced by acquisition protocols, software reproducibility, and methodological standardization. The review also addresses newer tracers, including 68Ga-FAPI for fibroblast activation, 18F-flurpiridaz for high-performance perfusion imaging, 18F-FDOPA for cardiac sympathetic dysfunction, and amyloid-binding PET radiopharmaceuticals for cardiac amyloidosis. Overall, recent evidence supports cardiac PET as a powerful platform for physiologic and molecular imaging, but not as a uniform or methodologically neutral technology. Its current value lies in selective, question-driven clinical use, whereas broader implementation will depend on tracer-specific validation, harmonized quantitative workflows, and clear demonstration of incremental benefit over existing imaging strategies. Full article

This study aimed to investigate the effects of dietary bile acids (BA) supplementation on serum antioxidant capacity, fecal fermentation characteristics, microbial diversity, and community composition in culled ewes. Twenty 5-year-old culled Hu ewes with similar body weights (42.95 ± 1.07 kg) were randomly allocated to two groups (n = 10 per group). The control group (CON) received a basal diet, while the treatment group (BA400) was fed the same basal diet supplemented with 400 mg/kg BA. Compared with the CON group, the BA400 group showed enhanced serum activities of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase, while also showing reduced concentrations of cortisol, malondialdehyde, and reactive oxygen species (p < 0.05). Fecal pH, ammonia nitrogen, total volatile fatty acids, and the concentrations and proportions of individual volatile fatty acids remained unaffected by BA supplementation (p > 0.05). Microbial analysis revealed that the BA400 group exhibited higher fecal bacterial richness and diversity than the CON group (p < 0.05). Analysis of similarities revealed significant differences between the CON and BA400 groups (R = 1.000, p = 0.007). Specifically, BA supplementation increased the relative abundances of beneficial taxa, including Verrucomicrobiota and Akkermansia, while decreasing potentially pathogenic bacteria such as Campylobacterota and Proteobacteria. These findings indicate that dietary BA supplementation improves serum antioxidant capacity and modulates fecal microbial diversity and community structure in culled ewes, suggesting that hindgut microbiota may contribute to the health benefits of BA supplementation in ruminant production. Full article

Rivers emit substantial amounts of carbon dioxide (CO₂) to the atmosphere, yet its response to heavy rainfall remains unclear with intensive anthropogenic disturbances. To fill the knowledge gap, this study investigated the dynamic variability of CO₂ partial pressure (pCO₂) and CO₂ emissions flux at the Chaohu Lake Basin, a watershed under intensive anthropogenic perturbations, based on field campaigns across diverse river systems during dry season, normal season, and post-rainfall periods. Results demonstrated marked differences in aquatic pCO₂ across river types, with urban rivers (3949 µatm) exhibiting significantly higher levels than non-urban counterparts (1423 µatm). Rainfall events elevated riverine pCO₂, but the effect size varied between river types (urban river versus non-urban river). In non-urban rivers, pCO₂ following heavy rainfall (2461 μatm) was significantly higher (p < 0.05) than those observed during both dry season (1096 μatm) and normal season (712 μatm). In contrast, urban rivers demonstrated only marginal pCO₂ elevation after rainfall (20–30%). Statistical analysis revealed that discharge, total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH₄⁺-N) showed significantly positive correlations with pCO₂, while dissolved oxygen (DO) and pH exhibited significantly negative correlations with pCO₂. Overall, rivers in the Chaohu Lake Basin act as significant sources of atmospheric CO₂, with an annual mean CO₂ emission flux of 297.84 mmol·m⁻²·d⁻¹, and the heavy rainfall events amplify riverine CO₂ emissions (629.91 mmol·m⁻²·d⁻¹), with observed enhancement effects exceeding 300% compared to baseline conditions. To accurately estimate the CO₂ emissions from human-dominated rivers, future research should emphasize the impacts of extreme or heavy rainfall events. Full article

The effect of Yucca schidigera extract (YSE; 10.8% saponins) on in vitro caecal disappearance (IVCD) was tested by incubating pre-digested feed with 0, 150, or 300 mg YSE/kg using caecal inocula from male and female pigs (Experiment 1). The apparent total tract digestibility (ATTD) of nutrients and fermentation products were assessed in vivo in 40 crossbred finishing pigs fed with 0 or 300 mg YSE/kg for 42 days (Experiment 2). In Experiment 1, YSE did not affect IVCD or gas production, but reduced caecal ammonia-N across sexes (p < 0.05). Caecal pH decreased progressively with increasing YSE in female-derived inocula only (p = 0.015), and volatile fatty acid (VFA) were suppressed in females at the highest dose (p = 0.013), while male-derived inocula remained unaffected. Entire males exhibited higher IVCD (p < 0.001) and lower ammonia-N (p = 0.034) and VFA production (p < 0.10) than females. In Experiment 2, YSE did not influence faecal ammonia-N, or VFA profile (p > 0.10), but reduced the ATTD of crude protein (p < 0.001) and organic matter (p < 0.001) relative to the control diet. YSE selectively modulated in vitro caecal fermentation in pigs, but these effects were not confirmed in vivo. Full article

Low-temperature stress severely restricts the engineering application of anaerobic ammonia oxidation (anammox) technology in municipal mainstream wastewater treatment, leading to its slower large-scale implementation relative to industrial wastewater and reject water treatments. The inhibitory effects of low temperatures on the anammox process cannot be merely ascribed to conventional microbial metabolic responses. Elucidating the specific mechanisms underlying low-temperature impacts on anammox bacteria is therefore critical for formulating targeted mitigation strategies. In this study, a meta-analysis was performed to compare the response patterns of specific anammox activity (SAA) and nitrogen removal rate (NRR) to temperature variations. SAA declines gradually with decreasing temperature, while NRR displays a more dramatic and stepwise reduction. The T₅₀ values (temperature corresponding to 50% of the performance at 30 °C) for these two parameters are 20 °C and 15 °C, respectively. Low-temperature inhibition of anammox is a multifaceted process, encompassing direct physiological disturbances to individual anammox cells and impaired nitrite bioavailability within the microbial community. To address these temperature-related bottlenecks, a conceptual hybrid nitrogen removal system was rationally optimized by integrating conventional strategies with an innovative split-flow influent regulation strategy. This hybrid system is anticipated to enhance the stability and treatment efficiency of anammox under low-temperature conditions, thus facilitating its broader engineering application in cold climate regions. Full article

Background: Arginase 1 deficiency (ARG1-D) is an ultra-rare urea cycle disorder characterized by hyperargininemia and progressive neurological impairment, including spasticity, loss of motor function, and reduced quality of life. Conventional management based on dietary protein restriction and ammonia scavengers rarely achieves adequate metabolic control or prevents neurological deterioration. Pegzilarginase, a recombinant human arginase 1 enzyme, is the first disease-modifying therapy for ARG1-D. Methods: We report the first Italian real-world experience with pegzilarginase in three pediatric patients with genetically confirmed ARG1-D enrolled in the phase 3 PEACE trial. Clinical, biochemical, functional, nutritional and quality-of-life data were retrospectively collected over a long-term follow-up (2003–2025). Outcomes were evaluated across three phases: treatment initiation (Start), a 13-month treatment interruption due to trial closure (Stop), and therapy re-initiation through an early access program (Restart). Results: Pegzilarginase rapidly normalized plasma arginine levels and was associated with improvements in motor function, spasticity, walking endurance, dietary protein tolerance, bone mineral density, and quality of life. During treatment interruption, all patients experienced biochemical worsening and clinical deterioration, including increased spasticity, reduced mobility, and emotional distress. Re-initiation of pegzilarginase restored metabolic control and led to progressive neurological and functional recovery, including partial reversal of long-standing motor deficits. Conclusions: This real-world experience supports pegzilarginase as a disease-modifying therapy for ARG1-D. Sustained normalization of plasma arginine, rather than subthreshold biochemical control, correlates with functional and neurological improvement and may partially reverse non-lesional metabolic brain injury. Early initiation of pegzilarginase, including in newborn-screened patients, may further modify the natural history of ARG1-D. Full article

Macrobrachium nipponense is one of the major economic species in freshwater aquaculture in China. As an important component of aquaculture ecosystem, microorganisms participate in key processes such as material cycling and water quality regulation, exerting significant impacts on the cultured organisms. In this study, high-throughput sequencing of the 16S rRNA, 18S rRNA, and ITS regions was employed to comparatively analyze the characteristics of microbial communities before and during the cultivation period, combined with correlation analysis of environmental factors. The results showed that the dominant microbial groups in the prawn pond water were Proteobacteria, Cyanobacteria, Ascomycota, Basidiomycota, Chlorophyta, and Arthropoda. The microbial community structure differed significantly between the pond water during the culture period and the pre-culture external river baseline: manifested as an increase in the relative abundances of Cyanobacteria, Chytridiomycota, and zooplankton, and a decrease in the abundances of Ascomycota, Basidiomycota, and Chlorophyta. Analysis of LEfSe revealed that the low-nitrogen pond was enriched with taxa such as Muribaculaceae; the high-nitrogen pond was enriched with taxa such as Cyanobium_PCC-6307; and the control pond was enriched with taxa such as CL500-29_marine_group. Functional prediction indicated that heterotrophic metabolism-related functions dominated the microbial communities. The abundance of fungal pathogens was significantly higher in the low-nitrogen group, while potential pathogenic bacteria were enriched in the high-nitrogen group. Ammonia nitrogen is a core environmental factor associated with differences in microbial community structure. The findings of this study can provide theoretical references and data support for water quality optimization and the construction of healthy aquaculture models in freshwater shrimp and crab farming waters. Full article

In situ coagulation is regarded as the most effective measure in response to the frequent metal spills in China. Excessive coagulant is often used in pursuit of extremely high removal rates of contaminants. Yet the secondary ecological impact of the iron-containing coagulation flocs left on the river sediments after emergency response is still unclear. In the current study, we investigated the impact of flocs derived from three different iron-based coagulants, polymeric ferric sulfate (PFS), polymeric ferric chloride (PFC), and ferric chloride (FeCl₃), on microbial communities in sediment based on microcosm experiments. Metagenomics, quantitative PCR, and determination of ammonia oxidation potential were adopted to elucidate community shifts. The results indicate that the community structure and function of microorganisms in sediments have been affected, especially processes and species related to nitrogen cycling, and the effect was coagulant-specific. Flocs retrieved from FeCl₃ caused a more pronounced decline in diversity, shifts in community composition, and decreased potential ammonia oxidation. Ammonia-oxidizing archaea (AOA) was more sensitive to iron-containing flocs than ammonia-oxidizing bacteria (AOB), while PFS-flocs tended to reduce multiple genes involved in nitrate reduction. This indicates that the pre-polymerization of inorganic coagulants may be the primary factor leading to different microbial ecological effects. Sulfate, on the other hand, may affect specific biogeochemical processes due to its competition for electron donors. Our results confirmed that even without heavy metals as contaminants, coagulant flocs alone could present an effect on nitrogen cycling in sediments. The results will provide a scientific basis for environmental emergency decision-making: in emergency response to metal pollution incidents, the use of coagulants should be limited to only the necessary level. Full article

Corn dust is an abundant agro-industrial by-product with potential as an alternative energy source. Its use in animal feeding, however, is restricted by high fiber content and low digestibility. This study evaluated the effects of non-starch polysaccharide (NSP) enzymes and yeast (Candida tropicalis KKU20) on the chemical composition, fermentation characteristics, and microbial populations of fermented corn dust. The experiment was conducted using a completely randomized design with a 3 × 2 factorial arrangement plus an additional control treatment. Factor A consisted of three levels of enzyme supplementation (0.02%, 0.04%, and 0.06% of dry matter), and Factor B consisted of yeast supplementation (without yeast or with C. tropicalis KKU20, approximately 1 × 10¹³ cells/g of inoculum). The control treatment consisted of fermented corn dust without enzyme or yeast supplementation. Samples were fermented for 15 days prior to analysis. Yeast inoculation increased crude protein and non-fiber carbohydrate contents while reducing neutral detergent fiber, acid detergent fiber, and acid detergent lignin (p < 0.05). Significant enzyme × yeast interactions were observed for several components, particularly fiber fractions (p < 0.05). The reduction in fiber was more pronounced when enzymes were combined with yeast. Predicted energy values, including metabolizable and digestible energy, were increased following yeast supplementation (p < 0.05). Fermentation characteristics were mainly affected by yeast. Yeast-treated samples exhibited higher pH and ammonia–nitrogen concentrations, indicating increased nitrogen turnover during fermentation. In contrast, lactic and propionic acid concentrations were higher in treatments without yeast, while yeast inoculation was associated with lower acetic acid and slightly higher butyric acid levels. Microbial analysis indicated interactions between treatments for lactic acid bacteria populations, reflecting competition for available substrates. No coliform bacteria were detected, indicating acceptable hygienic quality. Overall, yeast inoculation modified the chemical composition of corn dust, particularly by increasing crude protein and reducing fiber fractions, while NSP enzymes contributed to fiber degradation, especially when combined with yeast. However, these changes reflect compositional modification rather than confirmed feeding value, and further evaluation under rumen or in vivo conditions is required. Full article

The decarbonization of international shipping has accelerated interest in ammonia as a zero-carbon marine fuel. However, its acute toxicity poses safety challenges fundamentally different from those associated with LNG. This study presents a structured comparative regulatory analysis of the IGF Code and the IMO Interim Guidelines for Ships Using Ammonia as Fuel through a chapter-by-chapter review of key safety domains. The results show that, despite structural similarities, the two frameworks diverge significantly in their underlying safety logic: LNG regulation is primarily oriented toward flammability and explosion prevention, whereas ammonia regulation adopts a toxicity-driven safety architecture. This shift is reflected in ppm-level gas detection thresholds, ammonia release mitigation systems (ARMS), toxic area and Safe Haven concepts, broader secondary containment measures, and enhanced personnel protection requirements. These findings suggest that ammonia safety cannot be adequately addressed through incremental extensions of LNG-based rules alone. Instead, it requires a dedicated regulatory approach that explicitly incorporates toxic exposure management into ship design and operation. Full article

Although numerous studies have focused on the potential application of heterotrophic nitrification–aerobic denitrification (HNAD) bacteria in wastewater treatment, research exploring their potential in aquaculture biofloc systems remains limited. In this study, a promising HNAD strain, identified as Stutzerimonas stutzeri MJ20, was isolated from mature biofloc. This strain efficiently utilized low-cost carbon sources (e.g., glucose) and small-molecule carbon sources (e.g., sodium acetate and sodium succinate). Under conditions with glucose as the carbon source, a carbon-to-nitrogen (C/N) ratio of 15, pH 6–9, temperature 25–35 °C, salinity 0–35‰, and shaker speed of 0–150 rpm, it achieved removal rates of 95–100% for NH₄⁺-N, NO₂⁻-N, and NO₃⁻-N at initial concentrations of 100 mg/L each. Even at higher concentrations (up to 200 mg/L NH₄⁺-N and 500 mg/L for both NO₂⁻-N and NO₃⁻-N), removal rates exceeded 99%. Under mixed nitrogen sources, strain MJ20 demonstrated efficient nitrogen removal, preferentially utilizing NH₄⁺-N, with only minimal and transient accumulation of nitrite and nitrate. Genomic analysis revealed that MJ20 carries key denitrification genes, including napA, nirS, norB and nosZ, and possesses complete pathways for nitrate reduction to nitrogen gas and ammonia assimilation, although typical autotrophic nitrification genes were not detected. Combined genomic data and autotrophic culture experiments indicated that, in addition to utilizing various organic carbon sources, the strain also exhibited certain autotrophic growth capabilities. Furthermore, MJ20 showed strong flocculation ability (flocculation rate > 96% within 16 h), sensitivity to multiple common antibiotics, and no toxicity to zebrafish, demonstrating favorable biosafety. In simulated seawater aquaculture wastewater with a C/N ratio of 5, it achieved a total nitrogen removal rate exceeding 94% within 72 h. These results indicate that strain MJ20 possesses comprehensive advantages, including efficient nitrogen removal, broad carbon source adaptability, strong environmental resilience, minimal accumulation of intermediate nitrogen products, excellent flocculation ability, and high biosafety. These traits highlight its potential for application in biofloc systems and in treating aquaculture tail water with a low C/N ratio. This study provides theoretical insights and practical guidance for screening HNAD bacteria suitable for biofloc systems. Full article

Subterranean termites, particularly Odontotermes obesus, cause severe damage to forest nurseries and plantations in arid and semi-arid ecosystems. This study demonstrates the dual functional role of endophytic entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, in termite suppression and induction of plant defense responses. Laboratory bioassays revealed significantly higher virulence of M. anisopliae, with a lower LT₅₀ (lethal time required to cause 50% mortality) of 33.1 h compared to B. bassiana (46.7 h), a steeper probit slope (5.4 ± 0.3), and strong model fit (R² = 0.95), indicating rapid and synchronized mortality. Endophytic colonization varied across host species and application methods, with soil incorporation consistently outperforming foliar inoculation. Maximum colonization (82.5%) was recorded in Tecomella undulata and exceeded 80% in Azadirachta indica under M. anisopliae. Biochemical analyses revealed significant increases in protein (up to 3.5 mg g⁻¹), phenols (3.7 mg g⁻¹), and tannins (2.7 mg g⁻¹). Activity of defense enzymes was significantly enhanced, with catalase reaching 263.5 U mL⁻¹, while Phenylalanine ammonia-lyase and Tyrosine ammonia-lyase exceeded 170 and 198 U mL⁻¹, respectively, indicating activation of antioxidant and phenylpropanoid pathways. Molecular docking analysis further revealed strong interactions between fungal metabolites and termite cellulase, with Bassianin (−8.4 kcal mol⁻¹) and Tenellin (−8.1 kcal mol⁻¹) showing the highest binding affinities. These findings highlight the combined biochemical and molecular mechanisms underlying fungal-mediated termite suppression and plant defense induction, and future research should prioritize transcriptomic validation, rhizosphere microbiome interactions, formulation optimization, and long-term multi-location field evaluation to support sustainable termite management strategies. Full article

A study was conducted to evaluate the effect of neutral detergent fiber (NDF) levels of calf starter and weaning time on growth, rumen fermentation characteristics, serum metabolites, and rumen microbial diversity of Holstein calves. A total of 24 newly born male Holstein calves were randomly distributed to four groups in a completely randomized design with a 2 × 2 factorial arrangement of NDF levels (14% and 24%) and weaning time (d 44 and d 54). There was no interaction between starter NDF levels and weaning time for any trait except rumen acetic acid in the immediate post-weaning phase (p = 0.013). Starter NDF levels had no effect on growth, feed intake, and hay intake. Late-weaned calves had greater (p = 0.050) weight gain in the pre-weaning phase whereas, early-weaned calves showed greater weight gain (p = 0.004) and starter intake (p = 0.004) in the post-weaning phase although overall weight gain, and starter and hay intakes were not affected by weaning time. Rumen pH, ammonia nitrogen, and most volatile fatty acids remained unaffected by starter NDF levels and weaning except isobutyric acid which was greater in calves fed 24% NDF starter (p = 0.001) in the immediate post-weaning and isovaleric acid which was greater in early-weaned calves (p = 0.044) at the end of experiment. Serum metabolites were largely affected (p < 0.05) by starter NDF levels and weaning time in the pre-weaning phase only. Alpha diversity of rumen microbes was greater and chaotic in 14% NDF starter group (early- and late-weaned) in the pre-weaning phase which converged in the immediate post-weaning phase and diverged on starter NDF basis at the end of experiment. Microbial ecology at phylum and genus levels composition were greatly driven by starter NDF levels in the pre-weaning phase, by weaning time in the immediate post-weaning phase, and two distinct bifurcated microbial ecologies based on starter NDF levels appeared at the end of experiment. In conclusion, the comparable growth with distinct microbial diversity but largely in favor of 24% NDF starter suggests that calves can be subjected to early weaning with 24% starter NDF levels for smooth transition from liquid to solid feed in Holstein calves. Full article