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Fertilizer-derived uranium uptake in maize (Zea mays L.) : findings from pot and field experiments in Tanzania
Haneklaus, Nils; Mwalongo, Dennis A.; Mohammed, Najat K.; Lisuma, Jacob B.; Brink, Hendrik Gideon; Mupambwa, Hupenyu A.; Mazouz, Hamid; Chubur, Viktoriia; Roubik, Hynek; Qu, Guangfei; Waclawek, Stanislaw; Mtei, Kelvin M. (Elsevier, 2026-05)
Phosphate fertilizers can introduce uranium (U) into agricultural soils and potentially into edible crop tissues. This work evaluated U transfer from fertilizers into maize (Zea mays L.) under Tanzanian field and pot conditions. Three fertilizers with contrasting intrinsic U concentrations (39–160 mg kg⁻¹) were assessed in a single-season field experiment and in a replicated pot experiment, together with measurements of calcium (Ca) and exploratory bark and kaolin amendment treatments to mitigate U transfer from soil to plant. In the field experiments, interpreted descriptively, U concentrations were highest in soil (2.07–3.96 mg kg⁻¹), intermediate in roots (0.99–2.20 mg kg⁻¹), stems (0.39–1.09 mg kg⁻¹), and leaves (0.17–0.48 mg kg⁻¹), and lowest in grain (0.09–0.26 mg kg⁻¹, ash basis). In the pot experiment, one-way ANOVA showed highly significant treatment effects for U in soil, root, stem, and leaf compartments (all p < 0.001), and fertilizer/amendment interactions were significant among fertilized pots, indicating treatment-specific responses. Transfer coefficients for U and Ca supported a consistent partitioning pattern of soil > root > stem ≈ leaf > grain and showed that U transfer to grain remained strongly attenuated in both systems. Several amendment treatments, particularly kaolin and tree bark sawdust, were associated with reduced U concentrations and reduced transfer beyond the root compartment in the pot experiments, although no mechanistic measurements were made. Overall, the results identified fertilizer sources and compartmental partitioning as key controls on maize U accumulation and provided regionally relevant baseline data for exposure assessment and for future testing of low-cost retention measures under field-relevant conditions. HIGHLIGHTS • -Contrasting fertilizer sources produced different U accumulation patterns in maize. • -U was retained mainly in soil and roots, with low transfer to grain. • -Pot experiments showed significant fertilizer and amendment effects on U uptake. • -Transfer coefficients clarified U and Ca partitioning across plant compartments. • -Results provide baseline data for exposure assessment and mitigation testing.
Severe, primary, and incidental COVID-19 in hospitalised children, South Africa : 2020-2023
Goga, Ameena Ebrahim; Ramraj, Trisha; Cloete, Jeane; Mawela, Dini; Waggie, Zainab; Archary, Moherndran; Chinniah, Kogielambal; Jeena, Prakash; Tabane, Nomakhuwa E.; Van Zyl, Riana; Reubenson, Gary; Strehlau, Renate; Feucht, Ute Dagmar; Reddy, Tarylee; Mchunu, Nobuhle; Cawood, Shannon; Zuhlke, Liesl; Webb, Kate; Zar, Heather J.; Donald, Kirsten A.; Scott, Christiaan; Morrow, Brenda M.; Aldersley, Thomas; Du Plessis, Nicolette Marie; Chetty, Terusha; Velaphi, Sithembiso; Dangor, Ziyaad; Moore, David P. (International Society of Global Health, 2026-01-30)
BACKGROUND : Knowledge gaps persist regarding paediatric COVID-19 clinical presentation, treatment and outcomes in high HIV prevalence settings, with low COVID-19 vaccine coverage. METHODS : An ambi-directional cohort study was conducted in 13 South African public sector hospitals. Hospitalised children with SARS-CoV-2 infection or post-infection syndrome were included. Main outcomes measures included severe disease and primary COVID-19 (hospitalisation for SARS-CoV-2 infection). RESULTS : There were 2363 SARS-CoV-2 positive children included (March 2020 through May 2023); median age 23.6 months (interquartile range (IQR) = 4.3–98.2 months). Excluding missing values, 1618 (68.9%) children had primary COVID-19; 1121 (69.3%) of these had severe primary COVID-19. In the primary COVID-19 group with data, 318 / 1588 (20.0%) received intensive or high care, 121/1285 (9.4%) received a blood transfusion and 48/1616 (3.0%) died. Multivariable analyses demonstrated that severe primary COVID-19 was 32% higher in children aged 29–365 days (adjusted Risk Ratio (aRR) = 1.32 (95% confidence interval (CI) = 1.13–1.55); reference: 0–28 days), 13% higher with one or more comorbidities (aRR = 1.13; CI = 1.05-1.22)), and 14–22% lower during the Beta, Delta and Omicron periods (reference: ancestral period). Amongst all hospitalised children with a positive SARS-CoV-2 test, severe disease was commoner in underweight children (aRR 1.09; CI = 1.02–1.17, P = 0.013)). Severe signs were commoner in children living with HIV (CLHIV), 88/121 (72.7%), vs. HIV uninfected 1320 / 2104 (62.7%), P = 0.026, and in antiretroviral therapy-naïve CLHIV, (37 / 41 (90.2%), vs. CLHIV on therapy 51 / 80 (63.8%), P = 0.002). CONCLUSIONS : In a high HIV prevalence country, approximately 70% of children with a positive SARS-CoV-2 test were hospitalised for COVID-19 treatment; almost 70% of these children were severely ill. Controlling for other factors, disease severity was highest in the hypothesised pre-immunity Ancestral period. HIV infection and delayed ART initiation were associated with severe signs. In such settings, strengthening general child health programmes to reduce underweight and prevent or treat paediatric HIV may reduce the severity of new diseases of pandemic proportion.
Antibacterial resistance in urinary samples from long-term care-facility and community-dwelling older people in Gauteng, South Africa
Labuschagne, Olivia; Leigh, Stephanie; Kingsburgh, Chanel; Williams, Christopher David (Elsevier, 2026-03)
OBJECTIVE : Older populations (≥ 60 years) are frequent users of health care services, often vulnerable to infections and antimicrobial resistance (AMR). Urinary tract infection is often diagnosed in this cohort based on non-specific or atypical symptoms, yet empirical therapy seldom considers the potential influence of residential setting on resistance patterns. This study therefore aimed to quantify and compare the in vitro AMR profiles of urinary pathogens from these two settings and assessed temporal resistance trends to inform antimicrobial stewardship priorities. METHODS : A retrospective analysis was conducted using anonymised microbiology data from Ampath Laboratories in Gauteng. Urine cultures collected from older adults (≥60 years) between 2015 and 2023 were included. The five most common uropathogens were analysed. Resistance differences between long-term care facility (LTCF) and community samples were assessed using univariate and multivariable logistic regression models adjusting for age, sex, inpatient status, and sampling year. Temporal trends were evaluated using Kendall tau-b. RESULTS : A total of 50 704 urine cultures were analysed, of which 18.81% were from LTCFs. Escherichia coli and P. mirabilis showed consistently higher resistance in LTCF isolates. In E. coli, LTCF residence was associated with increased resistance to ciprofloxacin (adjusted OR 1.26; 95% CI 1.18–1.34), nitrofurantoin (1.55; 1.38–1.75), ceftriaxone (1.24; 1.14–1.34), amoxicillin/clavulanic acid (1.11; 1.05–1.19), and co-trimoxazole (1.10; 1.03–1.18). P. mirabilis showed similar patterns, with higher resistance to ciprofloxacin (2.16), gentamicin (1.64), fosfomycin (1.72) and co-trimoxazole (1.49). Trend analysis showed increasing fosfomycin resistance from E. coli isolates in both LTCFs (3.74% to 6.18%) and community settings (2.75% to 3.74%) and rising ceftriaxone resistance in community isolates (13.32% to 17.60%). CONCLUSIONS : LTCF residence was independently associated with higher AMR in several common urinary pathogens. These findings suggest that empirical urinary tract infection regimens commonly used in community-dwelling older adults may be inadequate for LTCF residents. Setting-specific antibiograms, improved diagnostic stewardship, and strengthened antimicrobial stewardship interventions are needed to support appropriate prescribing. Further studies incorporating patient-level clinical factors are warranted to refine empirical treatment recommendations for older adults across care settings. HIGHLIGHTS • Urinary tract infections are a common clinical diagnosis in older people. • Antibiotics are used excessively in older populations. • Where a patient resides has an impact on antimicrobial resistance. • Long-term care facility residents have higher antimicrobial resistance rates and require an enhanced approach to infection prevention and control.
Forecasting natural gas futures price volatility of the United States : national versus state-level climate concern indexes
Salisu, Afees A.; Ogbonna, Ahamuefula E.; Gupta, Rangan; Polat, Onur (Wiley, 2026)
This paper uses GARCH-MIDAS to predict US natural gas futures volatility using national and state-level Climate Concern Indexes (CCIs). We find that both national and state-level CCIs positively affect price volatility. Notably, models using state-level data—specifically those utilizing least-squares (LS) weighting combinations—surpass the GARCH-MIDAS-GECON benchmark and models relying solely on national CCI. These findings deliver substantial statistical and economic utility gains. Our results underscore the importance of incorporating heterogeneous climate concerns across US states to capture varied demand-supply conditions when forecasting energy market volatility.
A sensitive real-time PCR-based assay for the identification of Colletotrichum in phytosanitary and clinical applications
Phurbu, Dorji; Duan, Weijun; Crous, Pedro W.; Cai, Lei; Liu, Fang (MDPI, 2026-03)
Colletotrichum species are major plant pathogens and emerging opportunistic human pathogens. Due to their vast genetic diversity, existing diagnostic tools often suffer from narrow specificity or labor-intensive workflows. In this study, we developed a rapid, universal, and highly sensitive genus-specific real-time PCR assay utilizing a TaqMan MGB probe targeting the conserved 28S rDNA region. The assay demonstrated exceptional specificity, with no cross-reactivity against closely related fungal taxa or common co-occurring pathogens. The method exhibited high sensitivity, achieving a limit of detection (LOD) of 680 fg of genomic DNA. Furthermore, the assay was successfully validated using simulated environmental samples, where it accurately identified Colletotrichum within complex fungal communities. By providing a robust platform for genus-level screening, this methodology significantly enhances the efficiency of phytosanitary inspections and clinical diagnostics, facilitating timely biosecurity interventions and therapeutic decisions.