Research Articles (University of Pretoria)

Permanent URI for this collectionhttp://hdl.handle.net/2263/121

This collection offers open access to the full text of research articles published by staff, students and affiliates of the University of Pretoria. These items are identical in content to their published counterparts. It is linked to the Research Information System and complements the Annual Research Report.

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Surface engineered NiFe2O4/SnO2/CeO2 ternary heterojunction for dual applications in photocatalytic water treatment and supercapacitors
Oluwole, Adewunmi Olufemi; Sarr, Samba; Yusuf, Tunde Lewis; Tichapondwa, Shepherd Masimba; Daramola, Michael Olawale; Iwarere, Samuel Ayodele (Royal Society of Chemistry, 2025-11)
Please read abstract in the article.
Temperature-dependent phase evolution of the Gd3+ doped strontium compounds : structural and optical properties
Dlamini, C.; Mhlongo, M.R.; Maphiri, Vusani M.; Malevu, T.D.; Koao, Lehlohonolo Fortune; Motaung, Tshwafo Elias; Hlatshwayo, Thulani Thokozani; Motloung, Setumo Victor (Elsevier, 2025-12)
Please read abstract in the article.
The transition from first to second language instruction : South African year 4 learners
Le Roux, Mia; Geertsema, Salome; Milton, Carmen; Graham, Marien Alet; Wittstock, Kate; Gardee, Humayra; Carrim, Diyaanah Sattar; Veerasamy, Helene (Universidad de Castilla la Mancha, 2025)
ABSTRACT : The precursor literacy skills phonological and phonemic awareness play a central role in later literacy skills acquisition, especially during the transition from first language to second language mode of learning and teaching. Various research projects in South Africa found that English second language learners, even those who receive instruction in English from Year 0, do not have sufficient precursor and later literacy skills to support academic requirements. Learners who transfer from first-language instruction to second-language instruction in Year 4 may have even lower skills due to less exposure to the medium of instruction (English) on an academic level. This may further influence their literacy abilities. This study intended to analyse and determine the association of precursor literacy and later literacy skill competency measures of Year 4 learners who have recently transitioned from being taught in their L1 to English as their language of learning and teaching (LoLT). A quantitative, cross-sectional, descriptive, and correlational design was used. Non-probability, convenient sampling was employed. Results indicated that participants had limited precursor literacy and later literacy skills in English, demonstrating that transferring to their second language as the language of learning and teaching in Year 4 may be challenging. These challenges impact literacy skills necessary for academic success. Additionally, strong positive correlations between precursor and literacy skills assessed were determined. Therefore, intervention is essential to equip learners with strong literacy skills in the language of learning and teaching. RESUMEN : Las habilidades precursoras de lectoescritura y la conciencia fonológica desempeñan un papel fundamental en la adquisición posterior de habilidades de lectoescritura, especialmente durante la transición de la primera lengua a la segunda. Diversos proyectos de investigación en Sudáfrica han revelado que los estudiantes de inglés como segunda lengua, incluso aquellos que reciben instrucción en inglés desde el primer año (Año R), carecen de las habilidades de lectoescritura precursoras y posteriores necesarias para cumplir con los requisitos académicos. Los estudiantes que pasan de la instrucción en la primera lengua a la instrucción en la segunda lengua en el cuarto año pueden presentar habilidades aún menores debido a una más escasa exposición al inglés a nivel académico. Esto puede influir decisivamente en sus habilidades lectoescritoras. Este estudio tuvo como objetivo determinar y analizar la asociación entre las medidas de competencia en lectoescritura precursora y lectoescritura posterior de los estudiantes de cuarto año que recientemente han pasado de recibir instrucción en su primera lengua (L1) al inglés como lengua de aprendizaje y enseñanza (LDA). Se utilizó un diseño cuantitativo, transversal, descriptivo y correlacional. Se empleó un muestreo no probabilístico por conveniencia. Los resultados indicaron que los participantes tenían un nivel de alfabetización precursora y posterior limitada en inglés, lo que demuestra que la transición a su segunda lengua como lengua de aprendizaje y enseñanza en cuarto año puede ser difícil. Estas dificultades afectan las habilidades de lectoescritura necesarias para el éxito académico. Además, se determinaron correlaciones positivas y significativas entre las habilidades precursoras y de lectoescritura evaluadas. Por lo tanto, la intervención es esencial para dotar a los estudiantes de sólidas habilidades de lectoescritura en la lengua de aprendizaje y enseñanza.
A new kind of polynomials for finite groups
Asboei, A.K.; Anabanti, Chimere S. (Springer, 2025-09)
Please read abstract in the article.
Gender differences in response to strength and conditioning programs in collegiate athletes
Chen, Nora (Universidad Autonoma de Madrid y CV Ciencias del Deporte, 2025)
Research investigates how male and female college athletes react to strength and conditioning programs. This paper evaluates the impact of biological elements including muscle mass density and hormonal composition along with mental components including inspirational drive perception and performance awareness on shifting training success for athletic individuals of either sex. Men commonly achieve better results in muscle mass development because their higher testosterone creates improved strength gain potential yet women show different physical growth speeds and demonstrate superior physical flexibility at the same time. The research study based on primary data analysis for determine the overall research used Smart PLS Algorithm Model between the gender differences in response to strength and conditioning programs. Research demonstrates that individualized strength and conditioning programs need specific adjustments based on natural sex-based physiological differences which improve athletic performance while reducing safety risks. The knowledge of gender-specific responses enables strength and conditioning programming to produce better outcomes for male and female athletes who strive to achieve their best athletic level. Overall result found that directly link of gender differences in response to strength and conditioning programs.
The role of mathematical modelling in predicting and controlling infectious disease outbreaks in underserved settings : a systematic review and meta-analysis
Khumbudzo, Mavhunga; Duah, Evans; Grobler, Estelle; Maluleke, Kahlula (Wiley, 2025-09)
BACKGROUND AND AIM : Mathematical modelling plays an important role in public health by enabling the prediction of disease outbreaks, assessment of transmission dynamics and evaluation of intervention strategies. Although widely applied in high-resource settings, its use in underserved contexts remains underexplored. This review aimed to examine and synthesize current evidence on the application of mathematical modelling for predicting and controlling infectious diseases in underserved settings. METHODS : A comprehensive and reproducible search was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and population, intervention, comparison and outcome (PICO) frameworks across databases, including PubMed, Scopus, Medline, ScienceDirect and EBSCOhost. Keywords and Medical Subject Headings (MeSH) terms related to mathematical modelling and infectious disease control were applied. Two reviewers independently screened titles, abstracts and full texts, with a third resolving discrepancies. Thematic analysis and meta-analysis were used for synthesis. RESULTS : Out of 838 studies screened, 27 (3.2%) met inclusion criteria. Deterministic models were most used, followed by stochastic and agent-based models. Diseases modelled included COVID-19, malaria, tuberculosis (TB), Ebola, Zika, chikungunya, dengue, diphtheria, respiratory infections, visceral leishmaniasis (VL) and Mpox. Modelling predicted the impact of interventions on transmission, with pooled effect size (Ro) of 1.32 (θ = 1.3, p < 0.0001). However, challenges, such as data underreporting, gaps and inconsistencies, were common, potentially affecting model accuracy and real-world applicability. CONCLUSION : Mathematical modelling has demonstrated value in supporting infectious disease control in underserved settings. However, the predominance of deterministic models limits adaptability across diverse contexts. Poor data quality further constrains reliability. Future work should focus on expanding modelling approaches, strengthening data infrastructure and addressing a broader range of diseases. These findings can guide public health policy by supporting data-driven decision-making, improving resource allocation and integrating modelling into outbreak preparedness and response strategies in underserved settings.
Spatial distribution of COVID-19 diagnostic services in Mopani district, Limpopo Province, South Africa
Maluleke, Kuhlula; Musekiwa, Alfred; Mckelly, David; Baloyi; Mashamba‑Thompson, Tivani Phosa (Wiley, 2025-10)
INTRODUCTION : Access to healthcare facilities in rural areas remains a major challenge, particularly during the coronavirus disease 2019 (COVID-19) pandemic. This study investigated the spatial distribution and accessibility of COVID-19 point-of-care (POC) diagnostic services in Mopani District, Limpopo province, South Africa, using a geographic information system (GIS)-based approach. The aim was to identify areas where healthcare access requires improvement. METHODS : A descriptive cross-sectional study design was used, analysing secondary data through dasymetric mapping to disaggregate and re-aggregate population data into analytical units. Accessibility was measured by distances from residences to the nearest primary healthcare (PHC) clinics (<5 km) and from clinics to the nearest district hospitals (<30 km). Demographic and socio-economic data from Statistics South Africa were included for context. RESULTS : Mopani District had an estimated population of 1,202,916, with 942,801 (78.4%) residing within 5 kmof a PHC clinic. The district had 105 clinics, each serving about 11,456 people, and 72 (68.6%) of these clinics were within 30 km of a district hospital. The district contained both densely and sparsely populated areas, with high unemployment and low-income levels, particularly in rural regions. Limited public transport further constrained access. Ba-Phalaborwa, Maruleng, Greater Tzaneen and Greater Letaba have relatively good access, whereas Greater Giyani faces significant challenges. DISCUSSION : Although a majority of the population lived within 5 km of a clinic, notable gaps in accessibility remain. Improving transport infrastructure, using telemedicine and mobile health units, and implementing socio-economic support strategies, such as subsidized transport, can enhance access. Addressing geographic and structural inequalities in healthcare distribution is critical to promoting equity and improving health outcomes in rural districts like Mopani.
Exploring the genetic diversity, virulence and antimicrobial resistance of diarrhoeagenic Escherichia coli from Southern Africa using whole-genome data
Gichure, Josphat Njenga; Hald, Tina; Buys, Elna (Wiley, 2025-08)
INTRODUCTION : Previous studies, including our research, provide critical insights on the contamination of food, water and environment in the Southern African Development Community (SADC) with diarrhoeagenic Escherichia coli (DEC). This study used whole‐genome sequencing to investigate the genetic diversity, virulence‐associated factors and antimicrobial resistance (AMR) patterns of DEC isolated from children under 5 years old and food sources in Maputo and compared these findings with publicly available DEC genome assemblies from the Southern Africa region. METHODS : Whole‐genome sequence data from 11 DEC isolates from food, children under 5 and water sources in Maputo, Mozambique, were analysed alongside 125 publicly available DEC genomic assemblies from the SADC region. The latter were retrieved from the EnteroBase database (http://enterobase.warwick.ac.uk) and included isolates previously collected from food, animals and environmental sources. Genomic analyses were performed using the online pipelines provided by the Centre for Genomic Epidemiology (CGE), Denmark. Unsupervised hierarchical clustering was applied to visualize patterns in genetic diversity, AMR, virulence‐associated genes and plasmid content using the R software. RESULTS: Clustering based on single nucleotide polymorphism (SNP) and core genome multilocus sequence typing (cgMLST) alleles revealed associations based on geographic locations, sample niche, pathovar and O:H antigen, pointing to evolutionary relatedness between the clades with principal coordinate analysis uncovering this accounted for 27.55% of the genetic diversity. Virulence‐associated genes encoding for attaching and effacing (eae) (63.97%), heat‐labile toxin (LT) (25.00%) and Shiga toxin 1 (Stx1) (15.44%) were most abundant, with an inverse association between genes encoding for the presence of LT and eae. Resistance to folate pathway antagonists (sulfamethoxazole—55.9%), β‐lactamases (amoxicillin, ampicillin and piperacillin—all 54.4%) and aminoglycoside (streptomycin—55.1%) was most abundant. CONCLUSIONS : The study revealed region‐specific lineages, evidence of horizontal gene transfer and the clustering patterns suggest both localized and cross‐border transmission. The study provides insightful evidence on DEC transmission patterns associated with antimicrobial and disinfectant resistance and associated virulence factors.
Defining public health transformation : a scoping review
Phooko, Violet; Maluleke, Kuhlula; Ramatsokotla, Sebueng; Serite, Thato; Kgarosi, Kabelo; Sokudela, Funeka Brenda; Mashamba‑Thompson, Tivani Phosa (Wiley, 2025-06)
Public health transformation aims to instigate enduring changes in healthcare services, staff roles and patient involvement, fostering heightened satisfaction among patients and staff while bolstering financial sustainability. Public health transformation is the process of reorganizing and creating a shared vision to ensure the right mindsets, capacity, resources and workforce to deliver equitable Foundational Public Health Services and ultimately promote health, well-being and equity. Such transformation requires a fundamental change in public health systems’ structure, functioning and interactions, supported by continuous quality improvement, innovation, partnerships, community-driven efforts and systems change. This scoping review maps evidence of public health transformation. Searches encompassed databases including EBSCO Host, Academic Search Complete, Africa-Wide Information, Dentistry & Oral Sciences Source, Health Source–Consumer and Academic Edition, PUBMED and Scopus. Abstracts and full-text articles were screened by two independent reviewers against predefined criteria. Inclusion criteria spanned peer-reviewed published between 2013 and 2023. The quality of the included studies was assessed using the 2018 version of the mixed method appraisal tool. Screening results were reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) guidelines. Of 9509 articles retrieved, 808 duplicates were excluded, leaving 8692 for title and abstract screening. Following title and abstract screening, 105 articles were relevant and underwent full article screening, which resulted in 20 that became eligible for data extraction. Emergent themes included (1) Transformation in Public Healthcare; (2) Evaluation of Health Transformation Programs; (3) Financial Implications; (4) Public Health Access; and (5) Job Satisfaction. Theme 4 featured a subtheme addressing healthcare access for minority groups. Overall, the review highlights a dearth of evidence guiding policymakers in decision-making on public health transformation, oversight of vulnerable populations, financial implications, and healthcare accessibility. Solutions should prioritize a people-centred approach in both practice and research to effectively address these gaps.
Influences on e-governance in Africa : a study of economic, political, and infrastructural dynamics
Olumekor, Michael; Mangai, Mary S.; Madumo, Onkgopotse S.; Mohiuddin, Muhammad; Polbitsyn, Sergey N. (Wiley, 2025-03)
E-governance is considered one of the most important factors in delivering and administering public services in modern societies. However, data show that many African countries are currently lagging behind countries in other parts of the world. This manuscript investigates how various factors, including economic prosperity, government effectiveness, and infrastructural support, contribute to the growth and effectiveness of e-governance initiatives in 54 African countries. We specifically analyze the influence of three factors: economic prosperity (measured by GDP per capita), political competence (measured by government effectiveness), and infrastructural or technological support (measured by access to electricity). Panel data covering a 5-year period were retrieved from databases of the United Nations and World Bank, and a multiple linear regression analysis was used to analyze the data. We found that the three factors influenced e-governance to varying degrees. However, while infrastructural support and political competence were statistically significant, economic prosperity was not.
The benefits of sharing house-tree-fire-water-person drawings with parents when their anxious child is in sandplay therapy
Bredekamp, Judith; Theron, Linda C. (Wiley, 2025-09)
INTRODUCTION : The purpose of this study is to critically reflect on the value of the House-Tree-Fire-Water-Person (HTFWP) drawing as a tool to engage the parents of children aged 10–12 in sandplay therapy for Generalized Anxiety Disorder (GAD). To do so, we draw on empirical work that addressed gaps in the existing parent-psychologist alliance literature by exploring the usefulness of sharing the HTFWP drawing series with parents at feedback sessions. METHODS : We employed an instrumental, multiple case study design. The sample consisted of 7 cases, involving parents (n = 9) and child-clients referred for GAD (n = 7). Parent-generated data included the verbatim transcripts of initial semi-structured interviews, three HTFWP drawing elicitation conversations (i.e. HTFWP-facilitated feedback sessions) and a post-intervention semi-structured interview. Child-generated data included three HTFWP drawings and child-driven explanations of these drawings. Psychologist-generated data included journal-recorded reflections and process notes. Using reflexive thematic analysis, we identified patterns in these data. RESULTS : Findings suggest that an alliance created between parent and psychologist through sharing the HTFWP drawing series with parents was a win for everyone (parents, child and psychologist). This ‘win-win’ situation included enhanced care for the child, bolstered parental support and heightened efficacy for the psychologist. CONCLUSION : The HTFWP drawing has high potential to support the therapeutic process, with emphasis on its facilitation of a parent –psychologist alliance and spillover benefits for parents, the treating psychologist and the child-client.
Synergistic removal of hazardous dyes using a clay/carbon composite derived from spent bleaching earth : optimization using response surface methodology
Madhau , Freeman; Wu, Zhenjun; Shi, Yahui; Guo, Dongli; Wan, Dongjin; Tichapondwa, Shepherd Masimba; Wang , Yangyang; Chisadza, Bright; Zhu, Beibei (MDPI, 2025-04-17)
Industrial wastewater contains complex pollutants, including toxic dyes, necessitating effective and sustainable remediation strategies. Conventional treatment methods often struggle to remove multiple dyes simultaneously, underscoring the need for innovative adsorbents. This study investigated a clay/carbon composite (SBE/C (500 °C)) derived from spent bleaching earth (SBE) via pyrolysis for the simultaneous removal of methylene blue (MB) and malachite green (MG) dyes. The pyrolysis process significantly enhanced the specific surface area of SBE, improving its adsorption capacity. Using the Box–Behnken design (BBD) and response surface methodology (RSM), we optimized key parameters (pH, contact time, and dosage) at 45 °C and an initial dye concentration of 20 mg/L. The developed quadratic model demonstrated high predictive accuracy, with experimental results closely aligning with predictions (R2 = 0.9983 for MB, 0.9955 for MG), along with strong adjusted (R2 = 0.9962 for MB, 0.9896 for MG) and predicted (R2 = 0.9811 for MB, 0.9275 for MG) values. Under optimal conditions, the maximum adsorption capacities reached 27.77 mg/g for MB and 27.38 mg/g for MG. These findings highlight the potential of SBE/C (500 °C) as a sustainable and cost-effective adsorbent for the simultaneous removal of MB and MG from wastewater, offering a promising solution for environmental remediation.
Dimer fatty acid-based polyamide/organoclays : structural, thermal properties, and statistical analysis of factors affecting polymer chain intercalation in bentonite layers
Macheca , Afonso D.; Microsse, Diocrecio N.; Mujuri , Theophile M.; Tewo, Robert Kimutai; Mapossa, António Benjamim; Tichapondwa, Shepherd Masimba (MDPI, 2025-07-25)
This work investigates the potential industrial applications of two sodium bentonite samples (white and yellow), obtained from raw Ca-rich bentonite from Maputo Province in Southern Mozambique. Bentonite bio-organoclays were successfully developed from two Mozambican montmorillonite clays through the intercalation of protonated dimer fatty acid-based polyamide chains using a solution casting method. X-ray diffraction (XRD) analysis confirmed polymer intercalation, with the basal spacing (d001) increasing from approximately 1.5 nm to 1.7 nm as the polymer concentration varied between 2.5 and 7.5 wt.%. However, the extent of intercalation was limited at this stage, suggesting that polymer concentration alone had a minimal effect, likely due to the formation of agglomerates. In a subsequent optimization phase, the influence of temperature (30–90 °C), stirring speed (1000–2000 rpm), and contact time (30–90 min) was evaluated while maintaining a constant polymer concentration. These parameters significantly enhanced intercalation, achieving d001 values up to 4 nm. Statistical Design of Experiments and Response Surface Methodology revealed that temperature and stirring speed exerted a stronger influence on d001 expansion than contact time. Optimal intercalation occurred at 90 °C, 1500 rpm, and 60 min. The predictive models demonstrated high accuracy, with R2 values of 0.9861 for white bentonite (WB) and 0.9823 for yellow bentonite (YB). From statistical modeling, several key observations emerged. Higher stirring speeds promoted intercalation by enhancing mass transfer and dispersion; increased agitation disrupted stagnant layers surrounding the clay particles, facilitating deeper penetration of the polymer chains into the interlayer galleries and preventing particle settling. Furthermore, the ANOVA results showed that all individual and interaction effects of the factors investigated had a significant influence on the d001 spacing for both WB and YB clays. Each factor exhibited a positive effect on the degree of intercalation.
Whiteness at the abyss : reflections on a scene of attack
Hook, Derek (Springer, 2025-03)
This paper focusses on a series of online attacks that the author was subjected to after comments he had made in a closed lecture on the topic of ‘white anxiety’ were cut from the zoom recording and distributed widely online with the clear intent of causing outrage. The analysis of the material, which combines thematic, discourse analytic and personal reflections, yielded a series of core themes: 1) the role of the messages in consolidating an identity, 2) performative offensiveness, 3) perverse intimidations, 4) accusations/denials/expressions of racism, 5) the race-traitor as ideological dilemma, 6) antisemitism and 7) aggressive cordiality. The paper closes with a few reflections on the author’s enunciative position in respect of the attacks.
A systematic review of vegetation indices for potato growth monitoring and tuber yield prediction from remote sensing
Mukiibi, Alex; Machakaire, Allan Tatenda Batsirai; Franke, A.C.; Steyn, Joachim Marthinus (Springer, 2025-03)
Crop intelligence and yield prediction of potato (Solanum tuberosum L.) are important to farmers and the processing industry. Remote sensing can provide timely information on growth status and accurate yield predictions during the growing season. However, there is limited documentation on the most suitable vegetation indices (VIs) and optimal growth stages for acquiring remote sensing imagery of potato. To address this knowledge gap, a systematic review was conducted. Original scientific manuscripts published between 2000 and 2022 were identified using various databases. The findings indicate that satellite imagery is the most widely used source of remote sensing data for tuber yield prediction, whereas unmanned aerial vehicle systems (UAVs) and handheld sensors are more frequently applied for growth monitoring. The normalized difference vegetation index (NDVI), red-edge chlorophyll index (CIred-edge), green chlorophyll index (CIgreen), and optimized soil-adjusted vegetation index (OSAVI) are the most frequently used VIs for the growth and yield estimation of potato. The tuber initiation stage was found to be the most appropriate stage for remote sensing data acquisition. This review will assist potato farmers, agronomists and researchers in selecting the most suitable VIs for monitoring specific growth variables and selecting the optimal timing during the growing season to obtain remote sensing images.
Seroprevalence, characterization, and risk factors of brucellosis in cattle, sheep, goats, and camels in the Oromia region, Borena Zone, Ethiopia
Abichu, Getachew; De Massis, Fabrizio; Belete, Mekonnen; Bule, Duba; Benti, Teferi; Sombo, Melaku; Rufael, Tesfaye; Olani, Abebe; Scacchia, Massimo; Aliyi, Abede; Garofolo, Giuliano; Van Heerden, Henriette (Elsevier, 2025-11)
Brucellosis is a significant issue in the Borena Zone of Ethiopia, causing economic losses due to decreased milk production, abortions, infertility, and weak offspring. However, it is underreported and adequately addressed in the region. A cross-sectional study was conducted in the Gomole and Dhas districts of the Borena Zone in Ethiopia between November 2022 and June 2023 to estimate the seroprevalence of brucellosis in livestock. The study included cattle, camels, sheep, and goats, with random sampling at the individual and herd levels. A total of 490 cattle, 160 camels, and 330 each of sheep and goats were tested for seroprevalence. Random sampling was done on farms within the peasant association to test livestock at the individual and herd levels. Blood samples were collected from 490 cattle, 160 camels, and 330 each from sheep and goats. Samples were screened with the rose Bengal test (RBT) confirmed with the indirect enzyme-linked immunosorbent assay (iELISA). Polymerase chain reaction (PCR) detected Brucella species in blood clot samples collected from seropositive animals. The highest prevalence was observed in goats, with individual and herd-level rates of 10.0 % and 56.7 %, respectively. In contact, cattle had the lowest prevalence, 1.4 % at the individual level and 23.0 % at the herd level. Both B. abortus and B. melitensis were detected in cattle, sheep, and camels, while B. melitensis was the most common species found in goats. Statistically significant differences in brucellosis prevalence were observed among species, with the highest rates in the Gomole district compared to Dhas. Female animals had a higher prevalence than males, especially those with a history of abortion. Logistic regression showed that district and host species were associated with Brucella infection, with Gomole herds at higher risk. Brucella melitensis infections were common in sheep, camels, and goats, while B. abortus infections were mainly in cattle, with mixed infections in all species except sheep. Brucella melitensis infections were common in sheep, camels, and goats in the Oromia pastoral community, while B. abortus infections were mostly seen in cattle, with mixed infections in all species except sheep.
Experimental investigation of the effect of magnetic field placement on pressure drop, entropy generation, heat transfer, and thermal performance of Fe3O4/TiO2 magnetic nanofluids in turbulent flow
Adogbeji, Victor Omoefe; Govinder, Kuvendran; Sharifpur, Mohsen; Meyer, Josua P. (Elsevier, 2025-12)
Utilizing magnetic fields to manipulate fluid motion in ferrofluids has become a crucial approach for improving heat exchange efficiency in thermal applications, especially in pipe systems. This research conducts an experimental analysis of the effects of magnetic field (MF) patterns on heat transfer, entropy production, and the thermal efficiency of /Ti magnetic hybrid nanofluids (MHNFs) operating under turbulent flow regimes. Key parameters explored include nanoparticle concentration, effect of magnetic field placement, and signal waveform types (square, sine, and triangular). Results demonstrate that lower nanoparticle concentrations (0.0125–0.1 vol%) significantly improve thermal performance compared to deionized water and higher concentrations. The square waveform yielded the highest heat transfer enhancement (28.21 %), followed by sine (27.87 %) and triangular waveforms (22.81 %). Additionally, entropy generation was minimized through optimized magnetic field application and placement, highlighting its critical role in improving heat transfer efficiency. The thermal performance (TP) peaked at 26.33 % enhancement with 0.0125 vol%, while lower pressure drops were observed at 0.0125 vol% to be 7.67 %, and 0.00625 vol%, corresponding to 10.29 %. This study introduces a novel approach to optimizing heat transfer systems by integrating magnetic field waveform placement with precise nanoparticle formulations. The findings have significant implications for advancing energy-efficient cooling systems in thermal management applications, offering enhanced heat transfer with reduced energy losses.
The propensity of rural youth to take rain-fed smallholder farming as their livelihood strategy in KwaZulu-Natal (South Africa) : a multinomial logit analysis
Rambuda, Humbulani Portia; Wale, Edilegnaw; Chipfupa, Unity (Wiley, 2025-12)
With most unemployed youth residing in rural areas of South Africa, incentivising youth participation in smallholder farming can help address the increasing youth unemployment crisis. The study integrated the theory of planned behavior and the sustainable livelihood framework to investigate the factors influencing rural youth participation in smallholder rain‐fed farming activities. The data were collected from 224 rural youth in Dannhauser and Nquthu local municipalities, uMzinyathi District, KwaZulu‐Natal Province. Principal components analysis was employed to compute the different dimensions of positive psychological capital. The dimensions are then used as independent variables in the Multinomial Logit model. The findings revealed that endowment with positive psychological capital, dependency ratio, farming experience, engagement of other household member (s) in farming, access to agricultural training, access to land, and agricultural cooperative membership positively affect the propensity of rural youth to take rainfed smallholder farming as their livelihood strategy. The youth currently farming are doing so out of necessity, not out of interest. The circumstances force them to farm. In the long‐term, enhancing the profitability of small‐scale agriculture is the best mechanism to attract the youth.
Activation of chicken macrophages by isomalto/malto-polysaccharide (IMMP) is facilitated by toll-like receptor 4 (TLR4)
Ijaz, Adil; Putman, Max; Broere, Femke; Rutten, Victor P.M.G.; Jansen, Christine A.; Veldhuizen, Edwin J.A. (Elsevier, 2025-11)
Isomalto/malto-polysaccharide (IMMP) is a digestion resistant starch that has shown to increase SCFA production in the gut microbiota of human and mice to promote intestinal health. Like other prebiotics, it escapes enzymatic digestion in the small intestine and reaches the colon intact where it can interact with host epithelial and immune cells. Recently it was shown that in vitro IMMP can bind TLR4 on human macrophages resulting in their activation. The purpose of the present study was to investigate putative immune activation effects of IMMP upon direct interaction with chicken macrophages. IMMP stimulation in vitro caused morphological changes in the macrophage cell line HD11 reflected as reduction in cell size and numbers of cytoplasmic projections. Using the extracellular TLR4 blocking agent LPS-RS, it was shown that IMMP stimulation of HD11 cells involved TLR4 signaling. In addition, it activated HD11 cells and monocyte derived macrophages, resulting in the production of nitric oxide and increased phagocytic activity of HD11 cells. In conclusion, our results demonstrate an in vitro effect of IMMP on chicken macrophages which suggests that this carbohydrate compound may have immunomodulatory potential, hence may be used in the future as an alternative strategy to strengthen immune responsiveness to control intestinal infections.
Influence of dietary energy and lysine concentration on layer hen performance and egg quality during peak production
Coertze, Gerhard; Jansen van Rensburg, Christine (MDPI, 2025-06-17)
Limited published data are available on the current DLys requirements of Hy-Line Silver-Brown layers. The effects of energy (AMEn) and standardized ileal digestible lysine (DLys) concentration on the performance of Hy-Line Silver-Brown layers were studied from 20 to 35 weeks of age. The experimental design was randomized with twenty-four dietary treatments arranged as a 2 × 12 factorial with two AMEn concentrations (2750 and 2900 kcal/kg feed) and twelve levels of DLys (4.2, 4.5, 4.8, 5.1, 5.4, 5.7, 6.0, 6.6, 6.3, 6.9, 7.2, and 7.5 g/kg). Total egg weight (TEW), average egg weight, total egg number (TEN), laying rate, total feed intake, average daily feed intake (ADFI), mortality, hen body weight, hen body weight gain, eggshell thickness, eggshell breaking strength, yolk weight, albumen weight, and eggshell weight were recorded. An increase in energy content from 2750 to 2900 kcal AMEn/kg reduced ADFI (p < 0.001), egg mass output (p = 0.042), and feed conversion ratio (p = 0.018, g/g; p = 0.001, g/dozen) and increased the fat percentage in the liver (p = 0.028). An increased DLys intake from 529 to 882 mg/hen/day increased the TEN (p = 0.001), TEW (p < 0.001), and egg mass output (p < 0.001); improved the feed conversion ratio (p < 0.001); and reduced carcass (p = 0.001) and liver fat percentage (p = 0.05). Hy-Line Silver-Brown hens require no more than 780 mg (optimized egg production) and 880 mg (maximized egg weight) DLys/hen/day during pre-peak and peak production phases.

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