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Item The effect of lyophilisation on the physiochemical and biological properties of plant-based chitosan modified- poly lactic-co-glycolic acid microparticles(2025-06) Shatri, AMN; Lemmer, Yolandy; Mumbengegwi, DRTerminalia sericea, Lantana camara, Grewiatenax, and Corchorus tridens extracts are potent against gastrointestinal bacteria. However, metabolism by gastric acid reduces their efficacy and limits their mainstream uses. Encapsulating extracts into microparticles could improve biological properties while offering protection against gastric acid. Moreover, lyophilizing microparticle suspensions could reduce swelling and bursting, while improving microparticle stability during long-term solid storage. The study aimed to investigate the effect of lyophilization on the physicochemical and biological properties of plant-based chitosan-modified-PLGA (CMPLGA) microparticles over time. The formulated microparticles were lyophilized and analyzed for size, polydispersity index, zeta potential, and pH. The antibacterial and cytotoxicity of the lyophilized microparticles were also determined by agar disc diffusion and MTT. There was a significant increase in microparticle size after lyophilization due to aggregation. However, there was no statistically significant change in zeta potential and polydispersity index after lyophilization p < 0.05. Potent antibacterial activity of the micro-dissolutions was recorded against clinical Salmonella and Verotoxigenic Escherichia coli with the lowest recorded Minimum inhibitory concentrations of 6.25 ± 0.0 µg/ml with only minimal microparticle swelling and leakage. CMPLGA microparticles containing L. camara showed the lowest IC50 of 66.7 ± 0.005 µg/ml, indicating that microparticles are not significantly toxic to the NIH/3T3 mouse embryonic cells. The study indicates that lyophilization could be a useful method for long storage of CMPLGA microparticles as it does not preserve the surface charges and polydispersity index of the nanoparticles, while enhancing the efficacy and safety of the CMPLGA nanoparticles.Item Enrichment of extracellular vesicles using Mag-Net for the analysis of the plasma proteome(2025-07) Wu, CC; Tsantilas, KA; Park, J; Plubell, D; Sanders, JA; Naicker, Previn; Govender, I; Buthelezi, Sindisiwe G; Stoychev, SExtracellular vesicles (EVs) in plasma are composed of exosomes, microvesicles, and apoptotic bodies. We report a plasma EV enrichment strategy using magnetic beads called Mag-Net. Proteomic interrogation of this plasma EV fraction enables the detection of proteins that are beyond the dynamic range of liquid chromatography-mass spectrometry of unfractionated plasma. Mag-Net is robust, reproducible, inexpensive, and requires <100 μL plasma input. Coupled to data-independent mass spectrometry, we demonstrate the measurement of >37,000 peptides from >4,000 proteins. Using Mag-Net on a pilot cohort of patients with neurodegenerative disease and healthy controls, we find 204 proteins that differentiate (q-value < 0.05) patients with Alzheimer’s disease dementia (ADD) from those without ADD. There are also 310 proteins that differ between individuals with Parkinson’s disease and without. Using machine learning we distinguish between individuals with ADD and not ADD with an area under the receiver operating characteristic curve (AUROC) = 0.98 ± 0.06.Item Coupling of excitation energy to photochemistry in natural marine phytoplankton communities under iron stress(2025-07) Pupulewatte, H; Gorbunov, MY; Moore, CM; Selden, CD; Ryan-Keogh, Thomas J; Furbu, J; Hawley, R; Lohan, MC; Bibby, TS; Falkowski, PGOxygenic photosynthesis requires excitation energy transfer from light-harvesting complexes (LHCs) to reaction centers (RCs) to drive photochemical redox chemistry. The effective absorption cross section of RCs dynamically responds to the light environment on time scales of seconds to days, allowing rapid acclimations to changes in spectral irradiance and photoprotection under high light, thereby optimizing light absorption for photochemistry. Although energy coupling between LHC–RCs has been studied for decades in laboratory cultures, it remains poorly understood in real-world conditions, where it is potentially influenced by nutrients. In the oceans, one of the most critical micronutrients for photosynthesis is iron (Fe). To investigate the effects of Fe stress on the energetic coupling between LHC–RCs in natural phytoplankton assemblages in the Southern Atlantic Ocean, we assessed photophysiological responses using a pair of custom-built fluorometers measuring chlorophyll-a variable fluorescence and picosecond fluorescence lifetimes. Detailed analysis based on the functional absorption cross section of the oxygen-evolving complex, quantum yield of photochemistry, energetic connectivity of RCs, and the average lifetime of in vivo chlorophyll fluorescence suggested that between 10 and 25% of LHCs remain uncoupled from RCs and do not effectively contribute to photochemical charge separation. Addition of Fe to samples under trace metal-clean on-board incubations indicates relatively rapid recoupling (< 24 h) of antennae to photochemistry, followed by biophysical stabilization of recoupled complexes. Our findings highlight the crucial role of micronutrients in controlling the excitation energy transfer from LHCs to RCs in marine phytoplankton and the overall primary productivity in the real-world oceans.Item Utilizing aquifer hydraulic parameters to assess local and regional recharge potentials for enhancing water allocations in groundwater-dependent areas in De Aar, Northern Cape, South Africa(2025-09) Baloyi, L; Kanyerere, T; Muchingami, I; Pienaar, Harrison H; Igwebuike, N; Mukhawana, MBThe precise and accurate use of aquifer hydraulic parameters for assessing local and regional recharge potential for enhancing groundwater allocation planning is vital for many hydrogeological studies. The conventional approach for allocating groundwater presents a challenging scenario, as it remains uncertain whether the applied recharge estimate is local or regional recharge. The approach does not account for the extent of the aquifer recharge in terms of local and regional scale; instead, it assumes that recharge is distributed across the catchment. This study aimed to demonstrate the use of aquifer hydraulic parameters (transmissivity and storativity) to explain areas of potential recharge (local and regional) for enhancing groundwater allocation planning with a specific case study of De Aar, Northern Cape, South Africa. It argues that not integrating local and regional recharge potentials in planning for groundwater allocations can result in over- or under-allocation of groundwater resources to users. A constant discharge pumping test and recovery test matching the duration of pumping were conducted for data collection. The Flow Characteristics method was used as a diagnostic tool to understand the different aquifer flow regimes in the study area. To develop an integrated understanding of the groundwater system, a hydrogeological conceptual model was used to visualize areas with higher or lower recharge potential across local and regional scales. Results showed significant variability in transmissivity, ranging from 213 to 596 m2/d, and storativity, ranging from 0.0000297 to 0.000185. The transmissivity values suggest that groundwater moves faster; meanwhile, the storativity values suggest that the aquifer system has high water storage capacity. These results will assist water resource planners in making informed decisions on how to allocate groundwater to users. This study demonstrated that aquifer hydraulic parameters are a valuable tool for improving groundwater allocations, thereby highlighting the importance of considering areas for potential recharge, both local and regional, in planning groundwater allocation.Item The design of discrete-time systems with prescribed probability distribution and power spectrum pole(2025-04) McDonald, Andre M; Van Wyk, MA; Cilliers, Jacques EThis paper addresses the problem of designing nonlinear discrete-time dynamical systems for prospective use in low-complexity random signal generators. Drawing upon ergodic systems theory, we derive a novel method for designing nonlinear systems with zero-input responses that simultaneously satisfy two user-specified statistical metrics as specifications. These metrics are a piecewise-constant probability density function and a power spectral density expressed as a rational function with an arbitrary number of prescribed non-repeating poles. This new method configures a memoryless nonlinearity (i.e., a map) with a low-complexity hat-like structure as a recursive system with adjustable parameters, thereby yielding a simplified and explicit relationship between the system’s parameters and the statistical metrics of its response. This yields a matrix design approach that, unlike existing methods, affords the freedom to prescribe all of the poles as a set of non-repeating complex values without resorting to a numerical search over the parameter space for a candidate solution. Simulations are presented of elementary systems constructed using the novel method, and the link between the maps’ structure and the observed statistical behavior is expounded. More sophisticated systems with richer statistical metrics are constructed as examples that demonstrate the method’s versatility. We also demonstrate the independent adjustment of the center frequency and bandwidth of power spectrum modes during system design, which affords greater freedom than existing methods to select the power spectral density. We anticipate that the proposed method will find application in the construction of efficient random signal generators for Monte Carlo simulation in domains such as mobile communications, radar engineering, data encryption and optimization.Item Synthesis of iron-based metal–organic frameworks and carbon derivatives via unconventional synthetic methods and waste precursors with potential for gas storage(2025) Mosupi, Keaoleboga; Mthembu, NT; Masukume, Mike; Musyoka, NM; Langmi, HWMetal–organic frameworks (MOFs) have remarkable characteristics including high porosity as well as large internal surface areas. However, these materials have found very limited use industrially due to their high cost of production. The use of waste materials and industrial by-products to generate cheaper and environmentally friendly precursors could potentially open doors for industrial production of MOFs. Two types of Fe-based MOFs (Fe-MIL-53 and Fe-MIL-88B) were prepared using acid mine drainage (AMD) waters as a metal precursor source and waste polyethylene terephthalate-derived terephthalic acid (PET-BDC) as a linker via microwave-assisted and sonochemical-assisted synthesis procedures. Additionally, a carbonization strategy was utilized to enhance the porosity and surface area of these MOF materials. Upon carbonization, surface areas were drastically improved to above 600 m2 g−1 for both MIL-53 and MIL-88B prepared using the two unconventional methods. The obtained carbons also exhibited reasonable gas uptake capacities, with MIL-53 derived carbons having a higher hydrogen capacity of 1.32 wt% (at 77 K and 1 bar) and a carbon dioxide capacity of 2.09 mmol g−1 (at 298 K and 1 bar). The gas uptake capacities of MIL-88B derived carbons were found to be relatively low.Item Evaluation of the performance of a geogrid placed in a cement-treated subbase using accelerated pavement testing(2025-09) Smit, Michelle A; Rust, FC; Zamara, Z; Mazurowski, P; Kawalec, JRoad construction costs are high partly due to the scarcity and cost of good quality building materials. The inclusion of geosynthetics in flexible pavement structures has been shown to improve pavement performance. The study indicated the potential benefit of increasing the life of the pavement by adding a multi-shape geogrid layer to a cement-treated subbase. APT testing was conducted using the Heavy Vehicle Simulator (HVS) of the Council for Scientific and Industrial Research (CSIR) in South Africa. When the rutting data, deflection data and the stiffnesses back-calculated from FWD data are considered, it is evident that the inclusion of the geogrid into the cement-treated layer was beneficial and could increase the life of the pavement significantly. The addition of the geogrid to the structure led to an approximate 5% increase in the construction cost. This is negligible in comparison to the significant increase in pavement life. However, the results are valid for a relatively strong (10–30 million ESAL) design. Further work should include the use of the geogrid in a cement-treated base in a weaker pavement where the benefit could potentially be higher.Item A critical review on the applications of Sentinel satellite datasets for soil moisture assessment in crop production(2025-07) Mkhwenkwana, A; Matongera, TN; Blaauw, Ciara; Mutanga, OUnderstanding soil moisture dynamics in crop production is critical for optimising water resource management. The Sentinel satellite missions have significantly contributed to soil moisture monitoring by providing high-resolution, multi-sensor data. This review examines advancements in soil moisture assessment using Sentinel datasets, particularly in crop production. It highlights key challenges, evaluates their impact on monitoring accuracy, and explores potential methodological improvements. Findings indicate that Sentinel-1′s synthetic aperture radar (SAR) data, particularly VV and VH polarizations, and Sentinel-2′s multispectral indices, such as NDVI and NDMI, are widely integrated with machine learning algorithms to enhance soil moisture estimation. However, dense vegetation and complex topography reduce retrieval accuracy, necessitating sensor fusion and calibration for improved reliability. Sentinel-3 provides valuable surface temperature and land condition data for indirect soil moisture estimation, but its application remains limited due to higher uncertainty compared to SAR and multispectral approaches. Emerging trends suggest that machine and deep learning techniques, such as RF, SVR, and CNN, can enhance data fusion across Sentinel missions. Additionally, preprocessing steps such as RTC, speckle filtering, and the integration of multipolar and polarimetric data with physical backscattering models show promise in mitigating radar backscatter interference. Further development of robust retrieval models that incorporate topography, soil roughness, and texture are essential for improving soil moisture accuracy in diverse agricultural landscapes. This review underscores the need for continued methodological advancements to maximise the potential of Sentinel datasets for soil moisture monitoring in precision agriculture and water resource management.Item Green synthesis of amorphous silica nanoparticles (SiO2NPs) from sugarcane bagasse ash by sol-gel method(2025-11) September, LA; Kheswa, N; Seroka, Ntalane S; Khotseng, LSugarcane bagasse ash was utilized as a silica source in the sol-gel polymeric method used to produce amorphous silica nanoparticles (SiO2NPs). Sugarcane production process generates a huge amount of bagasse, an agricultural waste, which may constitute an environmental hazard if not properly managed. Due to sugarcane bagasse being a natural source of silica, this study produced silica nanoparticles as an alternate purpose for this waste. The present research uses L-cysteine hydrochloride monohydrate acid and citric acid to extract silica from sugarcane bagasse ash, with it being the first to utilize L-cysteine hydrochloride monohydrate in the sol-gel polymeric synthesis of silica. In order to study the extracted silica, XRD, FTIR, XRF, PIXE, SEM/EDS, TEM, and TGA were used to characterize the resulting silica xerogel in order to identify its elemental composition, surface morphology, functional groups, crystalline phases, thermal stability, and porosity. The purification techniques studied made it possible to produce silica nanoparticles with varying degrees of purity, a range of 67.25–94.58 wt% of silica xerogels were produced. Amorphous SiO2 nanoparticles were produced, with an average size of about 11–21 nm. The produced silica xerogel demonstrated porous network topologies with a high specific surface area and mesopore volume of 199.19, 469.09, 523.89 m2/g and 0.77, 0.64, 0.71 cm3/g using L-cysteine hydrochloride monohydrate, hydrochloric acid and citric acid respectively, according to the data. These materials, combined with morphological characteristics—large specific surface and pore volume—allow them to be used in a variety of technical domains, including biomedical, electronics, and optical.Item Towards energy efficiency in Radio Access Networks for 5G and beyond: A review of the state of the art, comparison of power consumption for popular open 5G RANs and techno-cconomic cost impact(2025-10) Ebrahim, Rozeena; Lysko, Albert A; Burger, Chris R; Vilakazi, Mlamuli C; Masonta, Moshe T; Banda, LThe increased energy demand in the fifth generation (5G) cellular networks and beyond has led to energy efficiency (EE) becoming a key research focus, particularly within the radio access network (RAN). This article presents a review of state-of-the-art techniques that address EE within the 5G RAN. These techniques are classified into six categories: hardware advancements, Multiple-Input Multiple-Output (MIMO) and antenna design, network architecture, sleep modes, optimisation techniques, and green energy sources. The article goes on to introduce a cost-effective power measurement setup designed for mobile network testbeds and demonstrates its use to compare the power consumption profile of different open-source RAN configurations deployed in the testbed. The proposed platform can be used not only to monitor and evaluate power consumption for different configurations of mobile network testbeds, but also to evaluate the implementation of different EE techniques. Further, we link the considered EE technologies with the capital and operational expenditures (Capex, Opex), total cost of ownership (TCO), and break-even points (BEP) across urban/rural deployments and open/proprietary deployment scenarios. Finally, by highlighting the least-explored areas and open research challenges, this work provides guidance for future research in this field.Item Distinct urinary proteome changes across estimated glomerular filtration rate stages in a cohort of black South Africans(2025-02) Khoza, S; George, JA; Naicker, Previn; Stoychev, SH; Mokoena, Rethabile J; Govender, Ireshyn S; Fabian, JKidney function parameters including estimated glomerular filtration rate (eGFR) and urine albumin excretion are commonly used to diagnose chronic kidney disease (CKD). However, these parameters are relatively insensitive, limiting their utility for screening and early detection of kidney disease. Studies have suggested that urinary proteomic profiles differ by eGFR stage, offering potential insights into kidney disease pathogenesis alongside opportunities to increase the sensitivity of current testing strategies. In this study, we characterized and compared the urinary proteome across different eGFR stages in a Black African cohort from rural Mpumalanga Province, South Africa. We stratified 81 urine samples by eGFR stage (mL/min/1.73 m2): Stage G1 (eGFR ≥ 90; n = 36), Stage G2 (eGFR 60–89; n = 35), and Stage G3–G5 (eGFR < 60; n = 10). Urine proteomic analysis was performed using an Evosep One liquid chromatography system coupled to a Sciex 5600 TripleTOF in data-independent acquisition mode. Nonparametric multivariate analysis and receiver operating characteristic (ROC) curves were used to assess the performance of differentially abundant proteins (DAPs). Pathway analysis was performed on DAPs. Creatinine-based eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. In this study, thirty-eight urinary proteins were differentially abundant for eGFR Stages 3–5 when compared to Stages G1 (AUC = 0.95; CI: 0.86–1) and G2 (AUC = 0.84; CI: 0.64–0.98). Notably, only six urinary proteins (Cystatin M (CST6), glutathione hydrolase 6 (GGT6), sushi domain containing 2 (SUSD2), insulin-like growth factor binding protein 6 (IGFBP6), heat shock protein 90 beta family member 1 (HSP90B1), and mannosidase alpha class 1A member 1 (MAN1A1)) were differentially abundant when comparing Stage G1 and Stage G2 with a modest AUC = 0.81 (CI: 0.67–0.92). Pathway analysis indicated that DAPs were associated with haemostasis and fibrin clot formation. In a rural cohort from South Africa, the urinary proteome differed by eGFR stage, and we identified six differentially abundant proteins which, in combination, could help to differentiate earlier eGFR stages with higher predictive accuracy than the currently available tests.Item Industry-led learning factories for 4IR skills and innovation: The CSIR approach(2025-10) Matebese, Belinda T, Belinda T; Ford, Merryl; Schoeman, Chanel; Coetzee, Christian J; De Ronde, Willis; Tyatyantsi, AyandaThe Fourth Industrial Revolution (4IR) demands a workforce equipped with technological competencies, yet South Africa faces significant challenges in bridging its skills gap. This paper introduces the Council for Scientific and Industrial Research (CSIR) Learning Factory (LF) as a scalable, industry-focused initiative to address these challenges. The CSIR LF integrates theoretical learning with practical application, fostering collaboration between academia, industry, and government. The LF is implemented in a phased approach, emphasizing its adaptability to South Africa’s socio-economic constraints. Key features include a blended learning model, modular training stations, and partnerships with Technical and Vocational Education and Training (TVET) colleges. The paper also highlights the LF’s impact on 4IR skills development, industry collaboration, and workforce readiness. Findings show that the CSIR LF can enhance employability, support industrial transformation, and align with national economic priorities, serving as a replicable model for upskilling South Africa’s workforce and fostering an inclusive, 4IR-driven economy.Item Cancer-derived exosomes: Mediators of immune crosstalk and emerging targets for immunotherapy(2025-10) Mahamed, R; Monchusi, Bernice A; Clement, P; Mirza, SExosomes, nanoscale extracellular vesicles secreted by various cell types, play pivotal roles in intercellular communication. In cancer, tumor-derived exosomes—referred to as cancer-derived exosomes (CDEs)—have emerged as critical regulators of immune evasion, tumor progression, and therapy resistance within the tumor microenvironment (TME). CDEs modulate immune cell function through the transfer of immunosuppressive proteins, cytokines, and non-coding RNAs, ultimately reprogramming immune surveillance mechanisms. This review provides an in-depth analysis of how CDEs influence major immune cell subsets—including T cells, B cells, NK cells, dendritic cells, macrophages, and myeloid-derived suppressor cells—thereby establishing an immunosuppressive TME. We also explore the potential of immune cell-derived exosomes (IDEs) as emerging immunotherapeutic tools capable of counteracting the suppressive effects of CDEs. Furthermore, we highlight exosome engineering strategies aimed at improving therapeutic cargo delivery, tumor targeting, and antitumor immune activation. Finally, we discuss how exosome profiling offers promise in liquid biopsy diagnostics and how integration with 3D tumor models and advanced bioengineering can accelerate the clinical translation of exosome-based cancer immunotherapies.Item Synthesis of MIL-53(Al) metal-organic framework from aluminium-lined multi-layered packaging materials and polyethylene terephthalate bottles(2025-11) Dlamini, NX; Ndamyabera, CA; Masukume, Mike; Musyoka, NM; Langmi, HWA promising approach towards the synthesis of metal-organic frameworks (MOFs) is the use of precursors that can be extracted from waste materials found in landfills. In this work, we explore a combination of two waste materials for Al-based MOF synthesis. Aluminium sulphate was successfully derived from Poly-Al pellets obtained from multi-layered packaging materials. Terephthalic acid (BDC) was obtained from polyethylene terephthalate (PET) waste bottles. Both precursors were employed as metal and organic linker sources, respectively to synthesise MIL-53(Al). The results are compared with those of corresponding MOFs synthesised from commercial precursors and partly waste precursors. The study revealed that the structural properties of MIL-53(Al) synthesised from the two waste materials are comparable to those obtained when the MOF is synthesised using commercial sources of precursors or partly waste precursors. The MOFs were highly crystalline and stable up to 500°C. An improvement was observed in the surface area of the MOF when synthesised from complete waste (1588 m2/g) as opposed to partly waste (1323 and 1197 m2/g) and commercial precursors (1468 m2/g). Although hydrogen adsorption capacity of the synthesised MOF materials was low at low pressures (< 0.5 wt% at 1 bar and 77 K), attributable to the narrow pore form of MIL-53(Al), this work demonstrates an approach to waste management while producing high-value materials for various applications.Item Oligochitosan conjugates of the antimalarialsdihydroartemisinin and lumefantrine: Synthesis, stability, cell viability, and antiplasmodial studies(2025-10) Matshe, William MR; Mvango, Sindisiwe; Malabi, Rudzani; Tantoh, Asongwe LA; Andraos, C; Famuyide, I; McGaw, L; Baijnath, S; Pilcher, L; Balogun, Mohammed OMalaria is treatable with several combinations of drugs, the most well-known and currently most effective being artemisinin-based therapies. Gastrointestinal absorption of these drugs can be poor and erratic if not taken with a fatty meal. Nausea and the loss of appetite, common symptoms of even mild malaria, can therefore jeopardize the effectiveness of the treatment. To enhance the bioavailability of artemisinin-based combination therapies, several lipid-based formulations and delivery systems have been investigated. In this study, we synthesized oligochitosan conjugates of the antimalarial drugs dihydroartemisinin and lumefantrine and examined their physical stability and biological activities. The hydrodynamic properties of both conjugates varied unpredictably under pH conditions like those found at different stages along the gastrointestinal tract and in plasma. The viability of Caco-2 cells exposed to the conjugates was also investigated in comparison to the free drugs. Both conjugates demonstrated significantly lower cytotoxicity compared to the free drugs at concentrations up to 0.5 mg/mL, particularly during the first 24 h of exposure. Despite this, they retained their antiplasmodial effect against Plasmodium falciparum in an in vitro assay at 1 µg/mL and 5 µg/mL. These new chitosan biomaterials hold great potential for further development into oral therapeutics that would not require fatty meal intake due to the intrinsic mucoadhesiveness of chitosan.Item A new dawn: Vitalising translational oncology research in Africa with the help of advanced cell culture model(2025) Klima, S; Hurrell, Tracey; Goolam, M; Gouws, C; Engelbrecht, A-M; Kaur, M; Van den Bout, IThe advent of in vitro models such as induced pluripotent stem cells (iPSC) and patient derived (disease) organoids is supporting the development of population and patient specific model systems reflecting human physiology and disease. However, there remains a significant underrepresentation of non-European, especially African model systems. The development of such models should be enthusiastically embraced by Sub-Saharan African countries (SSAC) and middle-income countries (LIMC) to direct their own research focused on the improvement of health of their own populations at a sustainable cost within their respective funding environments. Great care needs to be taken to develop national frameworks to direct, sustainably fund and support such efforts in a way that maximises the output of such models for the investment required. Here, we highlight how advanced culture models can play a role in vitalising local healthcare research by focusing on locally relevant health care questions using appropriate cell culture models. We also provide a potential national platform example that could maximise such output at the lowest cost. This framework presents an opportunity for SSAC and LMIC to base their healthcare research on locally relevant models to ensure that developed health care initiatives and interventions are best suited for the populations they serve and thus represent a reset in global health care research at large.Item Biogenic silica derived from sugarcane bagasse as a precursor material for unmodified SBA-15: Physicochemical properties and their use in biodiesel production from spent oil(2025) Matthews, T; Seroka, Ntalane S; Khotseng, LSustainable energy production requires innovative approaches to decrease the dependence on nonrenewable resources and reduce environmental impacts. In this proof-of-concept study, we investigated green Santa Barbara Amorphous 15 (SBA-15) catalysts using sugarcane bagasse ash (SCBA) as a silica source and incorporating organic acids and bases to create an eco-friendly synthesis pathway. These catalysts were applied in the transesterification of waste sunflower oil (WSO) to produce biodiesel. Although the overall biodiesel yields were relatively low, peaking at 5.603% FAME with the L-cysteine-modified SBA-15 catalyst (Lcys-500), the main objective of this study was to establish the feasibility of employing green SBA-15 materials as effective catalysts, rather than to optimise reaction parameters or maximise yield. Catalyst characterisation was carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA), confirming that the green SBA-15 retained key structural properties of conventional SBA-15, including ordered mesoporosity (p6mm symmetry) and spherical morphology with some variation in pore structure and thermal behaviour. Gas chromatography–mass spectrometry (GC–MS) was employed solely for biodiesel product analysis. FTIR spectra of the biodiesel confirmed successful transesterification, as indicated by characteristic C=O and C–O stretching bands. However, issues such as solidification of the CA-500-derived biodiesel and the low yield from the OP-after calcination sample (0.178%) underscore the need for further refinement. Importantly, catalyst modification strategies, such as surface functionalisation or metal doping, were beyond the scope of this initial study. Overall, the results support the feasibility of producing functional mesoporous SBA-15 catalysts from agricultural waste through green chemistry approaches. This study lays the groundwork for the development of environmentally friendly silica-based catalysts, with future research focussed on surface functionalisation to improve catalytic performance ecologically.Item BIOPERIANT12: A mesoscale-resolving coupled physics–biogeochemical model for the Southern Ocean(2025) Chang, Nicolette; Nicholson, Sarah-Anne; Du Plessis, M; Lebehot, Alice D; Mashifane, Thulwaneng B; Moalusi, Tumelo C; Mongwe, Precious; Monteiro, PMSWe present BIOPERIANT12, a regional ° ocean–ice–biogeochemical model configuration of the Southern Ocean (SO) based on the Nucleus for European Modelling of the Ocean platform. It is designed to investigate mean state, seasonal cycle, and upper ocean (< 500 m) dynamics, with a particular focus on processes influencing carbon, heat exchange, biogeochemical mechanisms, and the assumptions underlying physical–biogeochemical model parameterisations within the SO. Over the analysis period 2000–2009, the model demonstrates a stable and realistic upper ocean mean state compared to observation-based products. We use ocean biomes to delineate the major subregions and evaluate the biogeochemical properties of the model, including surface chlorophyll and partial pressure of carbon dioxide. BIOPERIANT12 captures key spatial and temporal features of SO biogeochemistry (BGC), though it tends to overestimate biological biomass and underrepresents high-frequency variability. The model shows skill in reproducing large-scale patterns and seasonal cycles across biomes, offering insights into regional dynamics that are often obscured in coarser models. Despite its limitations, BIOPERIANT12 provides a valuable high-resolution framework for process studies, model–data intercomparisons, and future investigations into mesoscale influences on carbon and heat dynamics. It offers a useful tool for addressing long-standing uncertainties in air–sea exchange and ecosystem variability in the SO.Item The impact of processing conditions on PGSS micronisation of Fischer-Tropsch waxes(2025) Swanepoel, Andri; Labuschagne, Philip W; Schwarz, CEMicronisation of two Fischer-Tropsch waxes with differing melting temperatures (Wax 1Item At scale synthesis and granulation of water-based aluminium fumarate metal-organic framework - crystallinity, textural properties, and structural integrity(2025-10) Muluvhu, MK; Eterigho-Ikelegbe, O; Mehlo, Thembelihle; Musyoka, N; Daramola, MOThe large-scale synthesis and shaping of metal-organic frameworks (MOFs) for industrial applications is a growing research focus and preserving the intrinsic properties of MOF powder during shaping is crucial for practical implementation. Herein, aluminium fumarate (Al-fum) MOF granules were produced with a 95 wt% MOF powder to 5 wt% binder ratio and the impacts of poly(vinyl alcohol) (PVA) and poly(vinylidene fluoride) (PVDF) binders on the properties of the shaped MOF granules were compared. The shaped granules were characterized for crystallinity, morphology, thermal stability, functional groups, textural properties, and mechanical strength. XRD confirmed that Al-fum MOF retained its crystallinity after granulation with PVA. MOF powder BET surface area of 952.23 m2/g was obtained using tap water, and 1117.95 m2/g with deionized water (DIW) as the solvent for synthesis. The binder additives resulted in 6.8 % loss in BET surface area upon granulation. Specifically, the PVA binder confers better mechanical strength, withstanding a load of 20 N, whereas Al-fum MOF/PVDF granules endured only 11 N. This study successfully demonstrated the feasibility of producing water-based Al-fum MOF powder at scale and industrial shaping it into granules while maintaining crystallinity, porosity, functionality, and sufficient mechanical stability.