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Over the years, spent potlining (SPL) treatment has only focused on the extraction of its hazardous compounds, especially fluorides and cyanides. The literature has not sufficiently addressed the optimization and kinetics of fluoride extraction using statistical modeling to determine relevant factors for efficient, cost-effective, and sustainable SPL treatment. Hence, this study is focused on response surface methodology (RSM) combined with central composite design (CCD) to statistically model fluoride extraction of SPL behaviour in acidic environments. Shrinkage core model (SCM) was used to investigate the kinetics of fluoride extraction. The RSM analyses suggested a second-order quadratic model with outstanding accuracy, statistically supported by R2 and adjusted R2 values of 0.986 and 0.973, respectively. The quadratic model indicates the main factors influencing fluoride extraction, showing the complex interactions of temperature, particle size, acid concentration, and leaching time. These main factors were observed to have significant effects on fluoride extraction, except for particle sizes of the SPL. The optimization process, a key success of this study, achieved fluoride extraction of 87.49% at specific factor levels of 48.43 °C, 0.752 mm, 1.2 M, and 10 min. Subsequently, the SCM investigations suggested that diffusion through a liquid film mechanism best approximates the fluoride extraction kinetic behaviour with R2 > 0.80 across varying temperatures. Investigations into temperature dependence with the Arrhenius plot further validated that the reaction kinetics were principally controlled by diffusion through liquid film, with an activation energy of 36.26 kJ/mol. Integrating these kinetic frameworks provides a novel approach to analyzing and optimizing SPL fluoride extraction. Overall, adopting the present study in the industrial settings with the optimized parameters will ensure efficient, sustainable, and cost-effective treatment of SPL.
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Fluoruros , Fluoruros/química , CinéticaRESUMEN
Based on current evidence and established critical thresholds for soil degradation indicators, it is concerning that over 60-70% of European soils are unhealthy due to unsustainable management and the impact of climate change. Despite European and national efforts to improve soil health, significant gaps remain. The proposal for a Soil Monitoring and Resilience Law, to be implemented by the European Union, seeks to establish a framework for soil monitoring and promote sustainable management practices to achieve healthy soils by 2050. This requires extensive data collection and soil monitoring systems to accurately estimate soil health across Europe, considering the diversity of soil types, climates, and land uses. To establish a framework for soil monitoring, we must understand the site-specific status of soil and the ranges of soil health indicators across specific pedoclimatic regions. In our study, we evaluated the soil status in agricultural areas in Denmark using soil health indicators and a site-specific benchmarking approach. We compiled nationally representative datasets, combining point and model-informed data of soil parameters such as organic carbon content, bulk density, pH, electrical conductivity, clay-to-soil organiccarbon ratio, water erosion, and nitrogen leaching. By categorizing Danish agricultural soils into monitoring units based on textural classes, landscape elements, and wetland types, we calculated benchmarks for these indicators, considering different cropping systems. Our approach provided detailed point-based results and a spatially explicit overview of the status of soil health indicators in Denmark. We identified areas where soil deviates from the benchmarks of different indicators. Such deviations might indicate soil functions operating outside the normal range, posing potential threats to soil health. This proposed framework could support the establishment of a baseline for assessing the directionality of future changes in soil health. Moreover, it is adaptable for implementation by other countries to support assessments of soil health.
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Benchmarking , Monitoreo del Ambiente , Suelo , Suelo/química , Dinamarca , Monitoreo del Ambiente/métodos , Cambio Climático , Agricultura , Conservación de los Recursos NaturalesRESUMEN
BACKGROUND: The aim was to explore behavioral factors relating to the prescription and communication of prescription-adherence messages for patients with acute febrile illness, from which to develop a training-and-communication (T&C) intervention to be delivered as part of a clinical trial. METHODS: The study undertook a content analysis of primary, qualitative data collection using in-depth interviews and focus group discussions, informed by the Capability, Opportunity, Motivation (COM-B) theory of behavior, the Theoretical Domains Framework (TDF), and Behavior Change Wheel (BCW) approach, in health facilities (39 health workers) and communities (66 community members) in the Shai-Osudoku District of Ghana. RESULTS: Health workers perceive that prescribers' and dispensers' communication with patients is influenced by the following factors: patient's educational level, existing disease conditions, health worker's workload, patient's religion, language barrier between health worker and patient, outcome of laboratory results, and medicine availability. Community members' adherence to prescription was influenced by the availability of money and affordability of medicine (outside of provision by the national health insurance scheme), the severity of the condition, work schedule, and forgetfulness. CONCLUSIONS: Our study contributes to knowledge on nesting qualitative methods in a clinical trial and reveals factors that affect the antibiotic prescription communication process. Tailored messages for patient-specific needs can shape antibiotic prescription adherence behavior and ultimately contribute to decreasing the incidence of antibiotic resistance.
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Antibacterianos , Prescripciones , Humanos , Antibacterianos/uso terapéutico , Ghana/epidemiología , Investigación Cualitativa , Farmacorresistencia Microbiana , Fiebre/tratamiento farmacológicoRESUMEN
BACKGROUND: Inappropriate antibiotic prescriptions are a known driver of antimicrobial resistance in settings with limited diagnostic capacity. This study aimed to assess the impact of diagnostic algorithms incorporating rapid diagnostic tests on clinical outcomes and antibiotic prescriptions compared with standard-of-care practices, of acute febrile illness cases at outpatient clinics in Shai-Osudoku and Prampram districts in Ghana. METHODS: This was an open-label, centrally randomized controlled trial in 4 health facilities. Participants aged 6 months to <18 years of both sexes with acute febrile illness were randomized to receive a package of interventions to guide antibiotic prescriptions or standard care. Clinical outcomes were assessed on day 7. RESULTS: In total, 1512 patients were randomized to either the intervention (n = 761) or control (n = 751) group. Majority were children aged <5 years (1154 of 1512, 76.3%) and male (809 of 1512, 53.5%). There was 11% relative risk reduction of antibiotic prescription in intervention group (RR, 0.89; 95% CI, .79 to 1.01); 14% in children aged <5 years (RR, 0.86; 95% CI, .75 to .98), 15% in nonmalaria patients (RR, 0.85; 95% CI, .75 to .96), and 16% in patients with respiratory symptoms (RR, 0.84; 95% CI, .73 to .96). Almost all participants had favorable outcomes (759 of 761, 99.7% vs 747 of 751, 99.4%). CONCLUSIONS: In low- and middle-income countries, the combination of point-of-care diagnostics, diagnostic algorithms, and communication training can be used at the primary healthcare level to reduce antibiotic prescriptions among children with acute febrile illness, patients with nonmalarial fevers, and respiratory symptoms. CLINICAL TRIALS REGISTRATION: NCT04081051.
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Antibacterianos , Sistemas de Atención de Punto , Niño , Femenino , Humanos , Masculino , Ghana , Antibacterianos/uso terapéutico , Prueba de Diagnóstico Rápido , Pruebas en el Punto de Atención , Prescripciones , Fiebre/diagnóstico , Fiebre/tratamiento farmacológico , Instituciones de Atención Ambulatoria , Atención Primaria de SaludRESUMEN
Improper discharge of cassava mill effluent (CME) has attracted much attention in major cassava-producing areas due to cyanide contamination. This study conducted a target survey on inhabitants and processors of the Akrofrom-Techiman cassava processing area in Ghana that aimed to assess their knowledge and perception of cyanide contamination from the CME discharge. The study further examined the effect of CME on the soil and groundwater at the processing area using physicochemical and bacteriological characterizations. Results revealed that inhabitants and processors exhibited high illiteracy on the impact of CME on cyanide contamination in the processing area. The study also indicated a wide characteristics of the soil at the processing site: pH (4.89-8.77), electrical conductivity (EC) (1063.00-1939.00 µS/cm), total dissolved solids (TDS) (523.90-963.50 mg/L), soil moisture (11.90-31.70%), free cyanide (0.02-0.33 mg/kg), and total cyanide (0.40-2.70 mg/kg). Results also showed that the physicochemical values of the CME were all above the Ghana Environmental Protection Agency (EPA) permissible limits and were unsafe for discharging into the environment. The range of physicochemical and bacteriological parameters of the two boreholes revealed the following: pH (7.85-8.74), TDS (165.77-192.37 mg/L), EC (320.87-396.20 µS/cm), free cyanide (0.13-0.16 mg/L), total cyanide (1.29-2.15 mg/L), and bacteriological parameter (220-622 cfu/mL). The two hand-dug wells also recorded pH (8.54-9.56), TDS (140.77-156.10 mg/L), EC (288.53-340.67), biological oxygen demand (BOD) (21.51-1.61 mg/L), chemical oxygen demand (COD) (13.5-16.5 mg/L), free cyanide (0.10-0.11 mg/L), bacteriological parameter (241-302 cfu/mL), and total cyanide (0.79-0.86 mg/L). The study concluded that the discharge of CME at the processing site contributes significantly to cyanide contamination of the soil and groundwater at the processing area.
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Agua Subterránea , Manihot , Contaminantes Químicos del Agua , Cianuros , Monitoreo del Ambiente , Ghana , Contaminantes Químicos del Agua/análisis , SueloRESUMEN
Remedial action for heavy metal-contaminated soils is imperative for preventing heavy metal leachability and minimizing environmental risks. This study evaluated the use of limekiln dust (LKD) as a heavy metal stabilization agent for Ghanaian gold mine oxide ore tailing material. Heavy metal-laden tailing material (Fe, Ni, Cu, Cd, and Hg) was collected from a tailing dam site in Ghana. Stabilization was done using acid neutralization capacity (ANC) and citric acid test (CAT) while all chemical characterization was done using X-ray fluorescence (XRF) spectroscopy. Various physicochemical parameters including pH, EC, and temperature were also measured. The contaminated soils were amended with LKD in doses of 5, 10, 15, and 20 wt.%. The results revealed that the contaminated soils had concentrations of heavy metals above FAO/WHO stipulated limits of 350, 35, 36, 0.8, and 0.3 mg/kg for Fe, Ni, Cu, Cd, and Hg, respectively. After 28 days of curing, 20 wt.% of LKD was found to be appropriate for the remediation of the mine tailings of all the heavy metals studied except Cd. Ten percent of the LKD was noticed to be enough in remedying soil contaminated with Cd since the Cd's concentration reduced from 9.1 to 0.0 mg/kg with a stabilizing efficiency of 100% and a leaching factor of 0.0. Therefore, remediation of contaminated soils of Fe, Cu, Ni, Cd, and Hg with LKD is safe and environmentally friendly.
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Mercurio , Metales Pesados , Oro , Ghana , Cadmio , Monitoreo del Ambiente , Polvo , Óxidos , SueloRESUMEN
The objective of this study is to elucidate the basic biological properties and function of TC0668 in vitro. Laser confocal microscopy and immune-electron microscopy were used to detect localization of TC0668 in Chlamydia-infected human epithelial cells, while the expression phase was investigated by qRT-PCR and western blot analysis. Protein array technology was employed to evaluate differences in cytokine secretion between cells infected with tc0668 single mutants and those infected with tc0668 null mutants. We found that TC0668 is restricted to the chlamydial inclusion. Translation and transcription of TC0668 were detected at 4 h and peaked at 16 h during the life cycle of Chlamydia in vitro. The cytokines produced by tc0668 single mutant infected cultures compared with tc0668 null mutant group indicated that 36 cytokines were downregulated, while 10 were up-regulated significantly. C. muridarum bearing a single tc0668 gene mutation have decreased urogenital pathogenicity that is explained by the effects of the mutation on the regulation of inflammation-related cytokine secretion.
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Infecciones por Chlamydia , Chlamydia muridarum , Chlamydia muridarum/fisiología , Citocinas/metabolismo , Humanos , Inflamación , MutaciónRESUMEN
One of the approaches for recycling and reusing agricultural and animal wastes is to pyrolyse the residues and subsequently use them as soil amendments. The prevalence of several feedstocks suggests that it is necessary to investigate the optimal combinations of feedstocks and pyrolysis temperature for use as soil amendments. This study was done to evaluate five combinations of raw materials (sugarcane bagasse, rice husk, cow manure and pine wood) and their biochars produced by slow pyrolysis at 300°C and 500°C for soil amendment. Several physicochemical properties (electrical conductivity (EC), pH, cation exchange capacity (CEC), total organic matter content (C) total porosity (TP), total nitrogen (N), particle density (PD) and bulk density (BD)) were investigated. Comparison among feedstocks showed that the highest PD, BD and CEC were observed in WM (cow manure-pine wood). The pyrolysis process increased the PD, TP, N and monovalent cations and decreased EC, CEC and BD. Compared to the feedstock, pyrolysis increased the N content, but higher temperatures lowered the N content. Pyrolysis at 500°C reduced the EC, N, CEC and biochar yield by 18%, 13%, 21% and 24% respectively, compared to 300°C. Pyrolysis at 500°C increased the pH, Na+ and K+ by 17%, 12% and 22%, respectively, compared to 300°C. Considering the physicochemical properties of biochar and the costs, the bagasse-wood-rice (BWR) combination and temperature of 300°C are suggested for biochar production for soil amendment.
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Oryza , Saccharum , Animales , Celulosa , Carbón Orgánico/química , Estiércol , Oryza/química , Saccharum/química , Suelo/química , TemperaturaRESUMEN
Trace metals contamination has recently been a major issue due to its damaging effects on public health and environmental receptors. This study focussed on the health risk assessment of trace metals (As, Pb, Cr, and Ni) associated with the direct intake of some selected food crops (namely cocoyam and plantain) at Abuakwa South Municipal, Ghana. The food crops and soil samples were selected randomly from three reclaimed mined sites and one non-mining site in the study area. Results from the trace metal concentration analyses in the soil samples showed that As, Cr, and Ni were above the control. The daily intake of metals (DIM), target hazard quotient (THQ), and carcinogenic risk (CR) assessments of health risks accompanied by the continuous ingestion of the selected food crops polluted through these trace metals were evaluated. 0.23 mg/kg and 0.05 mg/kg, 0.11 mg/kg and 0.02 mg/kg, 0.78 mg/kg and 0.65 mg/kg, and 0.23 mg/kg and 0.09 mg/kg were recorded for As, Cr, Ni, and Pb in that order in the cocoyam and plantain, respectively. The As and Pb concentrations in the food crops were above the WHO recommended limits. This implies that individuals within the vicinity are exposed to high levels of As and Pb through food intake which could result in varying health implications. The DIM and THQ for the studied trace metals were below their permissible limits suggesting that there is a tolerable non-carcinogenic adverse health risk level for adults and children within the studied area. In addition, the lifetime probability of contracting cancer by ingesting Ni, Pb, and Cr in plantain grown in the study area is high. It is recommended that regular monitoring of these trace metals in food crops be carried out in preventing their excessive accumulation.
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Metales Pesados , Contaminantes del Suelo , Adulto , Niño , Monitoreo del Ambiente , Contaminación de Alimentos/análisis , Ghana , Humanos , Metales Pesados/análisis , Medición de Riesgo , Contaminantes del Suelo/análisisRESUMEN
Copper contamination affects biological, chemical, and physical soil properties and associated ecological functions. Changes in soil pore organization as a result of Cu contamination can dramatically affect flow and contaminant transport in polluted soils. This study assessed the influence of soil structure on the movement of water and Cu in a long-term polluted soil. Undisturbed soil cores collected along a Cu gradient (from about 20 to about 3800 mg Cu kg soil) were scanned using X-ray computed tomography (CT). Leaching experiments were performed to analyze tracer transport, colloid leaching, and dissolved organic carbon (DOC) and Cu losses. The 5% arrival time () and apparent dispersivity (λ) for tracer breakthrough were calculated by fitting the experimental data to a nonparametric, double-lognormal probability density function. Soil bulk density, which did not follow the Cu gradient, was the main driver of preferential flow, while macroporosity determined by X-ray CT (for pores >180 µm) proved the best predictor of solute transport. Higher preferential flow due to the presence of well-aligned pores and small cracks controlled water movement in compacted soil. Transport of Cu was rapid during the first flush (≈1 pore volume) in association with the movement of colloid particles, followed by slower transport in association with the movement of DOC in the soil solution. The relative amount of Cu released was strongly correlated with macroporosity as determined by X-ray CT, indicating the promising potential of this visualization technique for predicting contaminant transport through soil.
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The growing interest in fast reactors demands further innovative technologies to enhance their safety and reliability. Understanding thermal hydraulic activities required for advanced reactor technology in design and development is key. However, knowledge of Heavy Liquid Metal (HLM) coolants technology is not mature. The liquid metal-cooled facilities are required experimental platforms for studying HLM technology. As such, efficient thermal hydraulic experimental result is important in the accurate validation of numerical results. In this vein, there is a need to closely review existing thermo-hydraulic studies in HLM test facilities and the test sections. This review aims to assess existing Lead-cooled Fast Reactor (LFR) research facilities, numerical and validation works and Liquid Metal-cooled Fast Reactor (LMFR) databases around the world in the last two decades. Thus, recent thermal hydraulic research studies on experimental facilities and numerical research that support the design and development of LFRs are discussed. This review paper highlights thermal hydraulic issues and developmental objectives of HLM, briefly describes experimental facilities, experimental campaigns and numerical activities, and identifies research key findings, achievements and future research direction in HLM cooled reactors. This review will enhance knowledge and improve advanced nuclear reactor technology that ensures a sustainable, secure, clean and safe energy future.
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During scram, the Control Rod Assembly (CRA) is quickly dropped into the core and as well, if any of the operating limits are exceeded, the CRA is dropped into the core within a stipulated time to shut down the reactor power as soon as possible. In this study, the Computational Fluid Dynamics (CFD) approach was used to investigate the CRA drop dynamics of a lead-based research reactor. To simulate the flow field around the CRA in the guide tube, a 3-dimensional model of the CRA in the LBE-filled guide tube was developed and discretized; and the averaged Navier-Stokes equations coupled with the dynamic mesh method were adopted. Considering the large mesh deformation in the LBE coolant domain while the CRA drops, the recently developed FSI method in the CFX code, namely the rigid body approach, was adopted, which falls under the monolithic method. In this method, the translational CRA wall, which is partially immersed in the LBE, was set as a rigid body. It has the advantage of updating and improving the mesh quality through the mesh and re-meshing technique during the process of computation. Compared with the results of the work done in the available literature, the CFD model proved to be applicable and reliable. From the results, the inherent high density among the LBE flow characteristics had the most influence on the drop time. The mass of the CRA impacts its driving force so that the drop time reduces when the CRA mass is increased. In conclusion, the method used in this study can be applied to compute and predict significant parameters which can serve as a reference for a suitable design of the CRA and its drive mechanism in the case of modification for safety.
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We investigated if subsoil constraints to root development imposed by coarse sand were affected by drought and biochar application over two seasons. Biochar was applied to the subsoil of pots at 20-50 cm depth in concentrations of 0%, 1%, 2%, and 3% (B0, B1, B2, and B3). Maize was grown in the same pots 1 week and 12 months after biochar application. The maize plants were fully irrigated until flowering; thereafter, half of them were subjected to drought. A new method for observing root growth dynamics and root length density in situ, the Rootsnap sensor system, was developed. The sensors were installed at 50 cm depth just below the layer of biochar-amended subsoil. Using data from a smaller experiment with grass, the calculated root length densities from the sensors were compared with data from scanning of manually washed roots. In year 2, we investigated the effect of aged biochar on root growth using only the root wash and scanning method. The Rootsnap sensor revealed that the arrival time of the first root in B3 at the 50 cm depth averaged 47 days after planting, which was significantly earlier than in B0, by 9 days. The tendency for faster root proliferation in biochar-amended subsoil indicates that biochar reduced subsoil mechanical impedance and allowed roots to gain faster access to deep soil layers. A linear regression comparing root length density obtained from the Rootsnap sensor with the scanning method yielded an r 2 of 0.50. Our analysis using the scanning method further showed that under drought stress, maize roots responded with reduced root diameter and increased root length density at 50-70 cm depth in the first and second year, respectively. The trend under full irrigation was less clear, with significant decrease in root length density for B1 and B2 in year 2. Overall, reduction in subsoil mechanical impedance observed as early arrival of roots to the subsoil may prevent or delay the onset of drought and reduce leaching of nutrients in biochar-amended soil with positive implications for agricultural productivity.
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Chlamydia muridarum, an obligate intracellular pathogen, was used to establish a murine model of female upper genital tract infection by Chlamydia trachomatis. TC0668 in C. muridarum is a hypothetical chromosomal virulence protein that is involved in upper genital tract pathogenesis. The infection of mice with the C. muridarum TC0668-mutant (G216*) strain results in less pathological damage in the upper genital tract. In this study, an isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics analysis was performed to identify differentially expressed proteins between TC0668 wild-type (TC0668wt) and TC0668 mutant (TC0668mut) strains at 6, 12, 18, and 24 h post-infection (p.i.). Of the 550 proteins differentially expressed at 18 h p.i., 222 and 328 were up-regulated and down-regulated, respectively, inTC0668mut-infected cells. The expression of seven up-regulated proteins (encoded by SRPRB, JAK1, PMM1, HLA-DQB1, THBS1, ITPR1, and BCAP31) and three down-regulated proteins (encoded by MAPKAPK2, TRAFD1, and IFI16) from the iTRAQ analysis were validated using quantitative real-time (qRT)-PCR. The qRT-PCR results were consistent with those of iTRAQ. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the differentially expressed proteins primarily participated in inflammatory responses, fibrosis, metabolic processes, and complement coagulation cascades, and were mainly enriched in the phosphatidylinositol 3'-kinase (PI3K)/Akt, nuclear factor kappa-B (NF-κB), and other signaling pathways. Using western-blotting and immunofluorescence detection, significant differences in activation of the PI3K/Akt and NF-κB signaling pathways were observed between the TC0668wt- and TC0668mut-infected cells. Differentially expressed proteins linked with inflammation and fibrosis were used in a protein-protein interaction network analysis. The results suggest that TC0668 may play a pivotal role in C. muridarum-induced genital pathology by inducing inflammatory responses and fibrosis, which may involve the activation of the PI3K/Akt and NF-κB signaling pathways.