Luu Tang Phuc Khang

Phosphorus (P) enrichment in urban rivers and canals is a major driver of eutrophication, yet its spatial and seasonal behavior remains poorly resolved in tropical monsoon systems. This study analyzed P fractions and associated metals in 48 surface sediment samples from 13 river and 11 canal sites during rainy and dry seasons. The results showed that iron‐bound inorganic (Fe‐Pi) and organic P (Fe‐Po) dominated sediment pools, with higher concentration in canals and during the dry season ( p < 0.05), while aluminium‐bound (Al‐Pi) and soluble P concentrations increased in the rainy season. Structural equation modelling (SEM) revealed contrasting phosphorus transformation pathways, with Fe–Pi acting as the dominant regulator in river sediments and Al–Pi together with soluble P exerting greater influence in canal sediments. Composite indices indicated substantial P enrichment across all site–season combinations, with DPS ranging from 295.90% to 323.49% and PSR from 2.96 to 3.23. The ERI remained relatively low (0.19–0.21), whereas PSC was negative throughout (−25.75 to −28.46 mol kg ⁻¹ ), indicating limited P storage capacity and potential P mobility in the sediments. Using eXtreme Gradient Boosting (XGBoost) coupled with SHapley Additive exPlanations (SHAP) interpretation, key environmental controls included cation exchange capacity (CEC), temperature, pH, salinity and grain size. Cross‐validated models achieved robust predictive performance, with the lowest prediction error for ERI (RMSE = 0.047). By integrating P fractionation, process‐based indices, SEM and interpretable machine learning, this study provides a transferable framework for assessing P loading and eutrophication risk in tropical urban river systems.

Science is a fundamental subject in Vietnamese primary education and provides an important context for developing students’ scientific literacy and competencies. Inquiry‐based science teaching (IBST) can support critical thinking, problem‐solving, and scientific reasoning when it is appropriately structured and scaffolded. However, evidence on the factors shaping teachers’ implementation of inquiry‐based science teaching in Vietnamese primary schools remains limited. This study therefore examined five factors including educational program (PR), approach to teaching methods (AM), student characteristics (ST), teaching resources (RE), and teaching application (AP), and their relationships with inquiry‐based teaching effectiveness (EF). Data from 306 primary teachers in Ho Chi Minh City were analyzed using descriptive statistics, reliability and exploratory factor analyses, multiple linear regression, and comparisons across grade level and teaching experience. The scales demonstrated acceptable‐to‐excellent internal consistency, and exploratory factor analysis supported a five‐factor structure for the independent variables and a distinct effectiveness construct. Regression analysis showed significant positive associations of AP, AM, and RE with EF and significant negative associations of PR and ST with EF. Grade‐level comparisons showed a significant difference for ST, while experience‐based comparisons indicated significant differences across the measured constructs. The findings indicate that teachers’ perceived effectiveness is associated not only with curriculum, student, and resource conditions but also with their capacity to orchestrate core scientific practices—questioning, investigation, evidence use, explanation, and communication. The study therefore contributes context‐specific evidence to primary natural science education and points to the need for science‐specific professional development and institutional support for inquiry‐based science teaching in Vietnamese primary schools.

Urban parks in rapidly developing cities face increasing heavy metal contamination, yet seasonal dynamics remain poorly understood. This study evaluated seasonal variations in heavy metal contamination and associated human health risks in two major parks in Ho Chi Minh City, Vietnam. We analyzed 48 surface soil samples (24 locations × 2 seasons) for eight metals using ICP‐OES. Pollution levels were evaluated using indices (EF, I _geo , CF, PER, mHQ, TU, and TRI) and GIS‐geostatistics. Sources were apportioned via multivariate analysis and positive matrix factorization (PMF), and health risks to children and adults were simulated using Monte Carlo methods. Al (Go Vap 12,475 ppm; Gia Dinh 13,998 ppm) and Fe (Go Vap 12,324.1 ppm; Gia Dinh 7620.7 ppm) dominated soil composition. In Go Vap, there was an increase in Al, Mn enrichment and Pb spikes (EF = 91.69) in the dry season; Gia Dinh had Cr (EF = 4.43) enrichment in the dry season and higher Mn (EF = 4.19) in the rainy season. PMF identified four sources: traffic solid waste (31.4%), traffic emissions and construction dust (15.8%), natural weathering (20.1%), and redox processes (32.7%). Spatial analysis revealed dry‐season high‐risk hotspots expanding to 39.41% of Gia Dinh and 36.02% of Go Vap park areas. Cr posed the highest health risk (HQ = 0.53 for children, 0.057 for adults), primarily via ingestion. All risk indices intensified during the dry season ( p < 0.05). Dry seasons increase the risk of contamination in tropical urban parks, especially Cr. This study supports seasonal monitoring and enhanced protection for children in monsoon‐affected green spaces.

Persistent organic pollutants (POPs) are among the most recalcitrant environmental contaminants due to their chemical stability, hydrophobicity, toxicity, and capacity for long‐range transport, yet mechanistic understanding remains fragmented across molecular, cellular, and systems scales, hindering integrated bioremediation strategies. This study synthesizes recent advances in bacterial POP degradation by integrating evidence from aerobic oxidative, anaerobic reductive, and cometabolic pathways across molecular, genomic, regulatory, metabolic, and multi‐omics levels. The analysis reveals that POP degradation is governed by highly modular and evolutionary dynamic networks involving catabolic operons, mobile genetic elements, regulatory hierarchies, and extensive metabolic rewiring. Notably, enzymatic promiscuity in aromatic‐ring‐hydroxylating dioxygenases and reductive dehalogenases, along with alternative pathway architectures and syntrophic microbial interactions, significantly enhances degradation efficiency. Systems‐level insights further highlight the importance of coordinated redox balancing, membrane adaptation, efflux mechanisms, biosurfactant production, and biofilm‐mediated resilience. Advances in synthetic biology, including pathway refactoring, enzyme engineering, designer consortia, and smart biosensors, provide new opportunities to expand substrate range, improve pathway control, and enable real‐time monitoring. However, challenges related to genetic stability, biosafety, and field robustness persist. Overall, the field is transitioning toward predictive, systems‐informed, and engineerable frameworks, emphasising the need for in situ multi‐omics validation and environmentally robust bioremediation solutions.

Widespread antibiotic use in aquaculture has increased selective pressure on resident bacterial communities, accelerating the emergence of resistance in key pathogens and raising concerns for animal health, environmental microbiomes, and food-chain safety. Reducing dependence on therapeutic antimicrobials requires alternative strategies that remain effective under the processing and biosafety constraints of intensive production systems, where recurrent bacterial diseases continue to cause substantial economic losses. Live probiotics, currently the most extensively studied microbiome-based intervention, have practical limitations, including reduced viability during feed pelleting and extrusion, transient gut colonization, strain-specific host responses, biosafety concerns related to horizontal transfer of antimicrobial-resistance genes, and variable regulatory requirements across regions. Postbiotics, defined as preparations of non-viable microbial biomass, with or without metabolites, that confer a demonstrated health benefit in the target host, and paraprobiotics, which emphasize inactivated whole-cell preparations that preserve surface-associated microbial molecular patterns, may help address several of these constraints. These approaches offer improved compositional definition, greater feed-processing stability, and a potentially more favorable biosafety profile. Because they are non-viable, their anti-pathogen effects do not depend on growth or competitive colonization but may instead involve preformed antimicrobial compounds retained in some preparations, interference with pathogen attachment, modulation of the intestinal environment, reinforcement of barrier function, and stimulation of host immune responses. This review synthesizes current evidence on postbiotics and paraprobiotics in aquaculture, with emphasis on structural classification, pattern-recognition receptor signaling, intestinal barrier function, innate immune priming, encapsulation technologies, and translational readiness. Taken together, available evidence supports postbiotics and paraprobiotics as promising, but not yet fully characterized, alternatives to live probiotics within antibiotic-reduction strategies for aquaculture. Progress toward commercial application will depend on resolving key questions related to dose–response relationships, processing stability in formulated feeds, and species-specific efficacy.

Industrial expansion in southern Vietnam has intensified concerns regarding seasonal air pollution dynamics and associated health risks under tropical monsoon conditions. However, assessments linking interannual variability, source structure, and population-specific health risks in tropical industrial zones remain limited. This study monitored ambient air quality at 37 sites across nine industrial zone clusters in southern Vietnam over five consecutive years (2021–2025), with biannual campaigns during the dry season (March) and rainy season (October). Two-way ANOVA identified significant effects of both year and season on concentrations of PM ₁₀ , SO ₂ , NO ₂ , CO, NH ₃ , and H ₂ S (all p < 0.05), with consistently higher dry-season levels, while noise remained invariant. Principal component analysis revealed clear seasonal separation along the primary axis (39.5% variance explained), and hierarchical cluster analysis confirmed season-dominated multivariate structure. Non-negative matrix factorization resolved four stable PM ₁₀ -related source factors, with Factors 3 and 4 showing pollutant signatures consistent with combustion- and sulfur-associated emissions and contributing most strongly during the dry season. The observed seasonal patterns are associated with differences in meteorological conditions and emission activities between the dry and rainy seasons. Probabilistic assessment identified H ₂ S, PM ₁₀ , and NO ₂ as dominant risk drivers, among which H ₂ S posed the greatest exposure concern across population groups, with a mean hazard quotient (HQ) reaching 10.26 in the dry season for the high-exposure group and P (HQ ⩾ 1) ≈ 1.000. GIS-based composite pollution mapping further revealed persistent high-risk hotspots in the East–Southeast industrial corridor, where high-risk area coverage increased from 27% in 2021 to approximately 36% during 2022–2025, a pattern spatially associated with industrial clustering, transport connectivity, and seasonal meteorological conditions. Overall, the findings suggest that the observed seasonal differences in source-related pollutant patterns, pollutant accumulation, and population health risk are consistent with the combined influence of meteorological conditions and seasonal emission activities in tropical industrial environments, providing evidence to support season-specific emission control and targeted public health protection strategies.

Spore‐forming Bacillus species are increasingly explored for their potential applications in antimicrobial activity and environmental bioremediation. However, comparative functional characterization of closely related strains with respect to biofilm inhibition, pathogen suppression, and ammonia removal remains limited. In this study, two bacterial isolates (PWR04 and SHPS6) were characterized using morphological, biochemical, and 16S rRNA gene sequencing analyses. Spore‐forming ability, stress tolerance (bile salt and pH), antibiotic susceptibility, antibacterial activity, biofilm inhibition, auto‐aggregation, and ammonia‐removal efficiency were systematically evaluated. Statistical analyses included t ‐test, one‐way ANOVA, and two‐way ANOVA. Both isolates were identified as members of the Bacillus cereus group, showing ≥ 99.80% sequence similarity. High spore survival was observed under bile salt (82.21%–95.99%) and acidic conditions (81.60%–99.48%). No inhibition zones were detected for ampicillin or cloxacillin, whereas inhibition zones reached up to 25.33 mm for chloramphenicol. Limited antibacterial activity was detected in agar well diffusion assays, whereas biofilm inhibition reached 91.79% in PWR04 and 90.00% in SHPS6 under specific conditions. Auto‐aggregation increased over time, reaching 76.24% in PWR04 and 71.84% in SHPS6 at 24 h. Ammonia‐removal efficiency was significantly affected by concentration and time ( p < 0.01), with maximum values of 20.00% (PWR04) and 18.00% (SHPS6). Although both isolates showed multifunctional antimicrobial and bioremediation traits, each displayed β‐hemolysis on sheep blood agar—a virulence‐associated phenotype that constitutes a clear safety concern. Genome‐based screening for hemolysin and enterotoxin genes and antimicrobial resistance determinants, together with in vivo validation, is therefore required before application.

Rising soil salinity poses a major challenge to global tomato production because it impairs germination, seedling development, and ultimately yield. Therefore, this study investigated the effects of NaCl (0–6 g/L) on germination, growth, and biochemical parameters of the black cherry tomato under in vitro conditions in the seedling stage. Germination percentage declined significantly with increasing salt concentration, from 100% at 0 g/L to 80% at 3 g/L, and seedling growth was strongly inhibited at 6 g/L. Moreover, seedling growth parameters, including fresh and dry biomass, root number and length, leaf number, leaf size, and plant height, were reduced as salinity increased. Biochemical analyses indicated that proline content increased concomitantly with declines in photosynthetic rate, total chlorophyll, relative water content, and membrane stability index (p < 0.05). Pearson correlation analysis confirmed a strong negative relationship between NaCl concentration and all measured traits (r = –0.90 to –0.99), and a strong positive correlation among germination, growth, and physiological variables (r = 0.93–0.99).

Encapsulated probiotics, which are promising approaches for improving aquaculture species’ performance and health, have incompletely characterized dose-dependent physiological and immunological effects. This study represents the first report evaluating the probiotic efficacy of a novel encapsulated Lysinibacillus sp. PWR01, originally isolated from rubber latex nodules, in Nile tilapia (Oreochromis niloticus). A total of 300 Nile tilapia (10.80 ± 0.07 g) was allocated to four experimental groups receiving 0, 10⁴, 10⁵, and 10⁶ CFU/g of encapsulated Lysinibacillus sp. PWR01 in their diet. At 8 weeks of the feeding trial, growth performance, feed utilization, serum antioxidant status, intestinal bacterial counts and immune-related gene expression were analyzed. Results demonstrated that fish fed 10⁶ CFU/g achieved a final weight of 51.48 g, representing a 9.88% increase compared with the control (46.85 g), while weight gain (WG) improved by 12.82% and specific growth rate (SGR) by 6.34%. Feed conversion ratio (FCR) was reduced by up to 18.42% at 10⁵ CFU/g relative to the control. Encapsulated groups enhanced serum superoxide dismutase activity without altering malondialdehyde levels, increased total intestinal bacterial and lactic acid bacteria counts, and selectively upregulated TLR2 and MHC II mRNA transcript levels. Histological analysis further revealed increased intestinal villus height and width in encapsulated-fed groups, while liver architecture remained normal across treatments. Multivariate analyses demonstrated strong positive associations among growth performance, gut microbiota enrichment, and immune gene expression. Resistance to Aeromonas hydrophila infection was significantly improved at higher dietary doses, with post-challenge survival reaching 61.67–75% in supplemented groups versus 45.00% in controls. These findings demonstrate that latex-derived Lysinibacillus sp. PWR01 acts as a strain-specific immunomodulatory probiotic that enhances growth, antioxidant capacity, microbial community balance, and disease resistance to Nile tilapia. Future studies should investigate the role of the Nrf2 antioxidant pathway, clarify TLR2-mediated immune signaling, and assess gut microbiota–immune system interactions within commercial-scale production systems.