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Development and characterization of an hTERT-HME1 three-dimensional spheroid cell culture model for breast cancer aetiology research
(North-West University (South Africa), 2026) Mavhungu, Mulatedzi Christopher; Venter, Gerda; Oyibo, Abraham; Gouws, Chrisna; van Niekerk, Alandi
Breast cancer (BC) is the leading malignancy in women, and exposure to estrogens such as those in combined oral contraceptives (17-β estradiol (E2); ethinyl estradiol (EE)), is an established risk factor, but the underlying mechanisms remain unclear. To investigate early events in estrogen driven breast carcinogenesis, in vitro systems offer ethical, time efficient, and species relevant alternatives to animal models. While traditional two-dimensional (2D) monolayer cultures offer simplicity and assay functionality, they poorly represent native tissue architecture and microenvironmental conditions, making three-dimensional (3D) culture systems a better model for carcinogenesis studies. Hence this study aimed to develop and characterize a 3D spheroid model of the non-cancerous human mammary breast epithelial cell line, hTERT-HME1, using a clinostat rotating bioreactor system (ClinoStar™, CelVivo ApS) as a model to study breast cancer aetiology. Prior to 3D experiments, 2D assays assessed estrogen proliferative effects and baseline cell health. The MTT assay showed non-linear, dose-specific proliferative responses to E2 (significant at 10 and 50 ng/mL) and EE (significant at, 5 and 25 ng/mL), while basic cell profiling demonstrated a linear relationship between cell density, protein production, and extracellular adenylate kinase release, thereby confirming assay reliability and reproducibility. During 3D model development, several spontaneous and non-spontaneous spheroid formation approaches were explored, and optimal spheroids with high cellular density and non-transparency only formed when 6000 cells were encapsulated per 1 µL sodium alginate droplet. Following successful model establishment and pre???characterization, spheroids were cultured for 30 days and analyzed every second day for cell growth, viability, cell death, and metabolic activity (soluble protein, ATP, adenylate kinase, glucose and pH). These parameters stabilized by day 18, indicating a viable, metabolically active, and functional model that remained consistent across independent batches, demonstrating reproducibility. Collectively, this work established a reproducible hTERT-HME1 3D spheroid model that provides a promising, controlled, physiologically relevant platform to investigate early mechanistic effects of estrogens and other risk factors driving BC development. Future work will focus on validating and qualifying the model for carcinogenesis studies by treatment with agents with carcinogenic potential.
Estimating the direct radiative forcing effect of aerosols on solar radiation using ground-based measurements over Gobabeb, Namibia
(North-West University (South Africa), 2026) Shilongo, Iipumbu Herman; Piketh, Stuart; Formenti, Paola; Marais, Eugene
Aerosols play a major role in modifying the Earth's energy balance through directly scattering and absorption of solar radiation. However, their radiative effects remain one of the large uncertaintiesin climate forcing estimation and that of local or regional is generally even larger. The Namib Desert of Namibia is a natural laboratory for both natural and anthropogenic aerosols produced either locally and transported from other regions in southern Africa. Despite the region'simportance for aerosols and climate, long-term aerosol radiative forcing effects have been understudied. This research dissertation focuses on improving the present understanding of aerosol optical properties and their radiative effects over a long-term period in this region. Thisresearch dissertation studied long-term analysis of aerosol optical properties and net surface radiation balance (under all-sky conditions) using two co-located ground-based observationnetworks, namely, the Aerosol Robotic Network (AERONET) and the high-quality Baseline Surface Radiation Network (BSRN) over Gobabeb, Namibia (23.5621° S, 15.0409° E, 405 m asl) using a 10-year dataset (2014 - 2023). The latter was also used to investigate the diurnal and seasonal variability of net surface radiation. However, due to the maintenance and calibration of the AERONET sunphotometer, aerosol optical properties and direct radiative forcing effects were analysed from November 2014 to September 2022. A comprehensive analysis of aerosol optical properties such as aerosol optical depth (AOD), Ångström exponent (AE), asymmetry factor (ASY), single scattering albedo (SSA), aerosol complex refractive index, and aerosol volume size distribution were characterised to assess their seasonal variability and long-term changes. The overall AOD 500nm at Gobabeb was 0.11 ± 0.11, which was mostly lower than other regions across southern Africa. Gobabeb experiences the highest AOD (at 500 nm) levels during the second part of the dry season (August - October). The increase in AOD during this time of the year has been attributed to the extensive biomass burning and mineral dust loadings across the subcontinent of southern Africa. Fine particles dominate the atmospheric loading at Gobabeb between March and October. This is likely attributed to the onset of biomass burning and urban-industrial emissions in the local area or transported from other regions in southern Africa. The AE at Gobabeb showed dominant presenceof coarse mode particles from November to February owing to local sources including mineral dust, sea salt, and meteorological conditions.The columnar water vapour (CWV) was found to be highest during summer and autumn. The increased water vapour can play a role in theatmospheric cleaning of aerosols and hygroscopic growth of certain hygroscopic aerosols. The aerosol volume size distribution (AVSD) revealed high volume concentration of fine and coarse mode particles during spring season. The single scattering albedo (SSA) showed stronger dominant presence of light-absorbing aerosols in winter, particularly in August (SSA440 = 0.91). The net surface radiation balance (difference between incoming and outgoing shortwave and longwave) showed an overall positive (warming) for the 10-year study period at Gobabeb. The highest (lowest) net surface radiation occurred as expected in summer with values of 128.2 ± 18.2 W/m2. The winter values were a factor of four lower(30.0 ± 15.1 W/m2). The net longwave radiation was found to have a cooling effect throughout the year. The shortwave downward radiation (SWD) showed high monthly variability during spring and summer months which areassociated with the frequent presence of clouds, fog and low-clouds, atmospheric water vapour and aerosols. The diurnal variation of the net surface radiation showed a maximum hourly mean of 419.4 W/m2 at 10:00 UTC. The aerosol direct radiative forcing (ARF) showed a heating effect in all seasons with maximum and minimum in spring (10.01 ± 14.74 W/m2) and autumn (3.68 ± 4.15 W/m2). The annual mean clear-sky ARF was - 3.40 ± 3.87 W/m2 at the top of the atmosphere (TOA) and - 10.60 ± 10.66 W/m2 at the Earth's surface. The resultant atmospheric warming was +7.20 ± 10.82 W/m2. This study demonstrated that aerosol optical properties, net surface radiation balance, and aerosol direct radiative forcing over Gobabeb exhibit pronounced seasonal variability influenced by aerosol loading, atmospheric water vapour, biomass burning activities, and regional meteorological conditions. Higher aerosol concentrations and stronger radiative forcing effects were observed during late winter and spring, while summer and autumn were characterised by relatively lower aerosol loading and enhanced atmospheric water vapour. The results showed that aerosols contributed to surface and top of the atmosphere cooling, while at the same time producing atmospheric heating through aerosol absorption processes. Furthermore, persistent fog and low-cloud conditions during spring and summer possibly played an important role in modulating the net surface radiation balance. Overall, the study provides crucial insights into aerosol-radiation interactions over the hyper-arid environment of Namibia and contributes important baseline information for future climate, air quality, solar energy, and environmental change studies in southern Africa.
Evaluating Different Soil Mapping Methods for Precision Agriculture
(North-West University (South Africa), 2026) Geraldes, Joaquim; van Zijl, George; Ramphisa-Nghondzweni, Dimakatso; Cloete, Willie
This study aimed to determine the most accurate and cost-effective method of soil mapping at field scale. To achieve this, a field was selected from the Free State Province in South Africa, and soil analysis was conducted on samples taken on a 1-hectare grid basis. The industry standard method of soil mapping in South Africa, Ordinary Kriging (OK), was evaluated alongside semi???variograms to determine the viability of using 1-hectare grids to sample soils. The accuracy of the OK maps was assessed using 10-fold cross-validation. Furthermore, digital soil mapping (DSM) with Machine Learning (ML) models were used to create maps from the same properties. The two models used were Cubist and Random Forest (RF), while the covariates used included Brightness Index (BI), Redness Index (RI), Saturation Index (SI), Normalised Difference Vegetation Index (NDVI), Digital Elevation Model (DEM) and Harvester Yield Data. The accuracy of the DSM with ML maps was tested by splitting the dataset 70% - 30%, where 70% of the dataset was used to train the model and 30% was used to validate the predictions. The statistics of the OK and DSM with ML maps were compared, and the maps were also visually inspected. Thereafter, fertiliser recommendation maps were created from the potassium (K) and phosphorus (P) maps of both the OK and DSM predictions. From these fertiliser recommendation maps a financial assessment was conducted of the two mapping methods. The semi-variograms showed that the 1-hectare grid system should not be used. The potassium (K) calcium (Ca), magnesium (Mg) and cation exchange capacity (CEC) OK maps all showed directionality. Both the DSM with ML and OK results could not be considered accurate enough. The financial analysis showed that due to the maps being inaccurate, there were huge losses when using both methods of mapping.
The metabolic consequences of two weeks chronic cannabidiol treatment in Kramnik mice
(North-West University (South Africa), 2026) Bhengu, Siyethemba; Mason, Shayne; Omotayo, Abiodun Olusola
The global burden of inflammatory diseases continues to rise, while conventional treatments are either minimally effective or cause potentially harmful side effects. This has prompted the search for alternative strategies, such as plant-derived compounds, which are readily accessible and have been shown to have mostly mild side effects. Among these is cannabidiol (CBD), a compound extracted from Cannabis sativa that does not produce psychotropic effects. The potential of this cannabinoid as an adjunct in neurological conditions has led to the approval of multiple CBD-containing formulations for various forms of epilepsy and multiple sclerosis (MS). Additionally, several preclinical studies have been conducted on various models of inflammation, in which CBD proved effective. Although many studies have examined this compound, there remains a critical lack of understanding of its effects on healthy subjects when administered repeatedly. Therefore, this study aimed to determine how a 10 mg/kg dose of CBD affected the metabolism of a healthy Kramnik (C3HeB/FeJ) mouse model when administered daily for 14 days. To this end, fourteen (n = 14) Kramnik mice were bred and divided into 2 groups: the CBD group and the vehicle control group. A 10 mg/kg dose of CBD or 10 µL of sunflower oil was administered daily for 14 days via the intrabuccal route. Urine and faeces were collected at the beginning of the study (day 1), on day 3, at the midpoint (day 7), and at the end of the study (day 14). Blood serum was collected only at the end of the study. Untargeted proton nuclear magnetic resonance (1H-NMR) metabolomics was performed on all urine and serum samples using the miniaturised 1H-NMR method, while faecal samples were analysed using a standard 1H-NMR method. Serum samples were re-analysed by liquid chromatography mass spectrometry (LC-MS/MS), using electrospray ionisation as the ion source and a triple quadrupole as the mass analyser. Here, amino acids and acylcarnitines were targeted. Raw data with high spectral density were obtained from urine and faecal samples, and relatively low spectral density from serum; all spectra were partitioned into small slices or bins. The quality of the bin data was assessed by calculating the coefficient of variation (CV%) of QC samples, which identified bins with non???repeatable QCs, which were subsequently excluded from downstream analysis. MetaboAnalyst was used to identify statistically significant bins, reducing the data to only those bins responsible for the observed changes in the dataset. Metabolites within these bins were identified in one-dimensional mode and confirmed in two???dimensional mode. Raw serum LC-MS/MS data were manually inspected by examining retention times and performing manual integration. The quality of data from both platforms (reduced data for NMR) was assessed using CV% and by monitoring the clustering of QCs in unsupervised groupings with the principal component analysis module in MetaboAnalyst. iii Given that no significant metabolic changes were expected a priori, a relaxed p-value of < 0.1, effect size, and log2 fold change were used to assess statistical significance. All results showed only moderate to minimal metabolic changes between the CBD and vehicle control groups across all collection points. As anticipated, metabolites associated with the gut microbiota and host-gut microbiota co-metabolism were identified, as were those associated with lipid and amino acid metabolism. Faecal metabolomics provided more metabolic information than the other two matrices, making it necessary to explore the faecal metabolome in CBD studies. This study primarily generates, with high confidence, hypotheses about which metabolic pathways to examine and/or which matrices to sample and provides extensive metabolic information relevant to the health of experimental subjects and to how it is affected by CBD administration or other medicinal substances. Additionally, this study demonstrates the feasibility of multiplatform metabolomics using samples of insufficient volume, a limitation inherent to mouse studies. In conclusion, a 10 mg/kg dose of CBD does not cause detrimental or sustained metabolic changes when administered daily for 14 days via the intrabuccal route. Acute effects appear to reverse over time, with almost a return to normal by the 14th and final day of the study.
Investigating the financial well-being of millennials through strategic literacy in the North West Province
(North-West University (South Africa), 2026) Stewart, Elrie .S
Financial well-being remains a significant challenge for South African millennials, particularly in the North West Province, where high unemployment, income instability, debt burdens, and cultural obligations such as "Black Tax" exacerbate financial vulnerability. While financial literacy is widely regarded as a key contributor to financial well-being, limited qualitative research exists on how millennials in this province experience and apply financial knowledge within their specific socio-economic and cultural context. This study aimed to investigate the financial well-being of millennials in the North West Province through the lens of strategic financial literacy. Data were collected through semistructured interviews with 19 millennials selected purposively using an interpretivist paradigm and qualitative single-case study design. Braun and Clarke's (2006) six-phased thematic analysis was used to analyse the data. These findings showcase seven major themes: learning financial literacy through life experience, income and employment, coping and survival strategies, debt and financial vulnerability, family responsibility and cultural influence, the need for practical financial education and mentorship, and financial socialisation. Although participants knew about financial principles, they were often unsure how to interpret their knowledge into good longterm financial behaviour because of structural constraints and cultural obligations. The study concludes that financial knowledge alone is insufficient to improve financial wellbeing. Practical, context-specific, and culturally sensitive interventions are essential. These findings contribute qualitative, province-specific insights to the literature and offer recommendations for policymakers, educators, employers, and financial institutions.