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Adsorption of methylene blue (MB) dye on ozone, purified and sonicated sawdust biochars
No full textThe synthesized biochars derived from sawdust (SD) SD ozone (SDO) biochar, purified SD (PSD) biochar, and sonicated SD (SSD) biochar, which was employed in the confiscation of methylene blue (MB) dye ion, were characterized employing “Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), and Thermal gravimetrical analysis (TGA).” The impact of various factors, such as pH, biochar dosage, and initial concentration, on MB dye sequestration, was tested in this study. It was found that the biosorption of MB dye to the various biochars was dependent on the solution pH, with optimum confiscation of MB observed at pH 12 for all biochars. Pseudo-second-order (PSO), Freundlich (FRH)- (SDO and SSD biochars), and Langmuir (LNR)- (PSD biochar) models were used to best describe the biosorption process of MB dye to various biochars. Based on the LNR model fitting to the experimental data, the optimum sorption capacities obtained using SDO, SSD, and PSD biochars were 200, 526, and 769 mg/g, respectively. Electrostatic interaction and hydrogen bonding played an important role in the interaction mechanism between the various biochars and MB dye. Hence, these studied SDO, PSD, and SSD biochars prepared from cheap, easily accessible, biodegradable, and non-hazardous agro-waste materials can be effectively used for the removal, treatment, and management of MB dye as well as other industrial effluents before their disposal into the environment
Particle swarm optimization for an optimal hybrid renewable energy microgrid system under uncertainty
No full textMicrogrids can assist in managing power supply and demand, increase grid resilience to adverse weather, increase the deployment of zero-emission energy sources, utilise waste heat, and reduce energy wasted through transmission lines. To ensure that the full benefits of microgrid use are realised, hybrid renewable energy-based microgrids must operate at peak efficiency. To offer an optimal solution for managing microgrids with hybrid renewable energy sources (HRESs) while taking microgrid reserve margins into account, the particle swarm optimisation (PSO) method is suggested. The suggested approach demonstrated good performance in terms of charging and discharging BESS and maintaining the necessary reserve margins to supply critical loads if the grid and renewable energy sources are unavailable. On a clear day, the amount of electricity sold to the grid increased by 58%, while on a partially overcast day, it increased by 153%. Microgrids provide a good return on investment for their operators when they are run at peak efficiency. This is because the BESS is largely charged during off-peak hours or with excess renewable energy, and power is only purchased during less expensive off-peak hours
Microplastic concentrations and risk assessment in water, sediment and invertebrates from Simon's Town, South Africa
No full textPlastic pollution is an ever-increasing threat globally and poor waste management in South Africa has caused an increase in plastic leakage into the environment. Plastic waste in the environment are categorized according to size and plastic particles smaller than 5 mm in size are regarded as microplastics (MPs), and little to no research has been done on MPs pollution within the marine coastal environment and rocky shores in South Africa. Sampling was done in February 2020 at a rocky shore within Simon's Town Marina, Cape Town. MPs were extracted from collected water (n = 5), sediment (n = 5) and biota (n ≤ 30) samples. The extracted MPs were further classified based on shape, colour, size and an attenuated total reflectance Fourier-transform infrared (ATR-FTIR) instrument was utilized for polymer type identification The risks posed by MPs because of concentration at which they occurred and chemical composition were assessed in all the sample types. As expected, MPs were higher in sediment (38 ± 2 MP/kg) than in water (0.37 ± 0.06 MP/L) as the area has low water energy, allowing MP particles to settle within the sediment. Filter-feeding organisms had the lowest average MP particle concentrations (0.28 ± 0.04 MP/g) but displayed the highest variation of MP particle colours due to the non-selective feeding strategy, where other feeding strategies ingested mostly black/grey particles. The dominant MP size was between 100 μm and 500 μm in size for all samples combined, with the most abundant MP polymer type being nylon (27.27 %), polyethylene terephthalate (PET) (18.18 %) and natural MP particles such as cotton (18.18 %). The risk assessment indicated that polymer type poses a greater risk of MP pollution than MP concentrations
Anticancer diterpenes of African natural products: mechanistic pathways and preclinical developments
No full textBackground:
The African continent is home to five biodiversity hotspots, boasting an immense wealth of medicinal flora, fungi and marine life. Diterpenes extracted from such natural products have compelling cytotoxic activities that warrant further exploration for the drug market, particularly in cancer therapy, where mortality rates remain elevated worldwide.
Purpose:
To demonstrate the potential of African natural products on the global stage for cancer therapy development and provide an in-depth analysis of the current literature on the activity of cancer cytotoxic diterpenes from African natural sources (to our knowledge, the first of its kind); not only to reveal the most promising candidates for clinical development, but to demonstrate the importance of preserving the threatened ecosystems of Africa.
Methods:
A comprehensive search by means of the PRISMA strategy was conducted using electronic databases, namely Web of Science, PubMed, Google Scholar and ScienceDirect. The search terms employed were ‘diterpene & mechanism & cancer’ and ‘diterpene & clinical & cancer’. The selection process involved assessing titles in English, Portuguese and Spanish, adhering to predefined eligibility criteria. The timeframe for inclusion spanned from 2010 to 2023, resulting in 218 relevant papers. Chemical structures were visualized using ChemDraw 21.0, PubChem was utilized to search for CID numbers.
Results:
Despite being one of the richest biodiverse zones in the world, African natural products are proportionally underreported compared to Asian countries or otherwise. The diterpenes andrographolide (Andrographis paniculata), forskolin (Coleus forskohlii), ent-kauranes from Isodon spp., euphosorophane A (Euphorbia sororia), cafestol & kahweol (Coffea spp.), macrocylic jolkinol D derivatives (Euphorbia piscatoria) and cyathane erinacine A (Hericium erinaceus) illustrated the most encouraging data for further cancer therapy exploration and development.
Conclusions:
Diterpenes from African natural products have the potential to be economically significant active pharmaceutical and medicinal ingredients, specifically focussed on anticancer therapeutics
Polyhydroxyalkanoate production by actinobacterial isolates in lignocellulosic hydrolysate
No full textPolyhydroxyalkanoate (PHA) polymers are environmentally friendly alternatives to conventional plastics. In support of a circular bioeconomy, they can be produced by growing microbial strains in waste materials, including lignocellulosic biomass, such as Canola fines (straw). In this study, PHA and polyhydroxybutyrate (PHB) production by a selection of seven wild-type actinobacterial strains, including three strains of Gordonia species, were assessed. When grown in defined media and hydrolysates of Canola fines, the highest amounts of PHB were produced by Nocardia gamkensis CZH20T (0.0476 mg/mL) and Gordonia lacunae BS2T (0.0479 mg/mL), respectively. Six strains exhibited a substrate preference for cellobiose over glucose, xylose, and arabinose in the hydrolysates. Analysis of Fourier transform infrared spectra indicated that the strains produced co-polymers of short- and medium-chain-length PHAs. None of the core phaABC genes were found on defined operons in the genomes of the top PHB-producing strains (all Gordonia strains, N. gamkensis CZH20T, and Streptomyces sp. strain HMC19). The Gordonia strains all harbored three phaA genes, a single phaB gene, and, with the exception of strain BG1.3 (with two predicted phaC genes), a single phaC gene. Predictive analyses of the proteins likely to be translated from the phaC genes revealed PhaC proteins of 37.7–39.2 kDa from Gordonia sp. strain BG1.3, G. lacunae BS2T, and N. gamkensis CZH20T; PhaC proteins of 106.5–107 kDa from Gordonia sp. strain JC51; and the second PhaC from Gordonia sp. strain BG1.3 and N. gamkensis CZH20T, possibly representing a new class of PHA synthases
Using fire, planting, and topsoil translocation for restoration in South African fynbos: assessing the success and cost-effectiveness of various restoration treatments
No full textThe successful restoration of endangered habitat types at a low cost is of vital importance. We tested how successful and cost-effective six combinations of restoration treatments were in the Cape Floristic Region of South Africa. Treatments were applied to an area that was primarily covered invasive alien grasses. Treatments that tested combinations of burning, direct sowing of seed, and planting of seedlings, aimed to test the synergistic effect of three treatment factors. Topsoil translocation aimed to determine if this, combined with planting, can restore native shrub cover and whether the addition of mulch and seed can improve overall success. The mechanical removal of invasive grasses, sowing and planting, were tested in the absence of fire. Both topsoil translocation treatments and the treatment that had been burned, sown and planted (“Burn-sow-plant”) led to plant species richness resembling near-pristine plots and approximately 30% higher than the burn-only treatment (“Burn”). Native shrub cover was the highest for treatments which included planting. Survival for planted species was 36–41% higher for Burn-sow-plant. The contribution of sowing was low, with 9–16% of species sowed being present across treatments. We show that topsoil translocation can be successful if combined with planting. Burn-sow-plant was most successful at a reasonable cost, despite planting being expensive, whereas Burn and Burn-sow were less successful, but cheaper. The treatment in which grass was removed before sowing and planting was the least successful and most expensive. We conclude that the most successful treatments are not necessarily the most expensive
Exploring the associations of tobacco smoking and serum cotinine levels with selected inflammatory markers in adults with HIV in South Africa
No full textThis study examined the associations between tobacco smoking and serum cotinine levels, an objective biochemical measure of tobacco smoke exposure, with markers of inflammation, i.e., interferon-gamma (IFN-γ), interleukin 10 (IL-10), interleukin 2 (IL-2) and tumour necrosis factor-alpha (TNF-α) in people living with HIV (PLWH).These specific markers were selected because of their hypothesised associations with smoking, PLWH and their outcomes. In a random sample of ≥ 18-year-old PLWH receiving care at 17 public healthcare facilities across the Western Cape Province in South Africa, data collection included self-reported smoking history, and serum levels of cotinine and selected inflammatory markers. The inflammatory marker data were log transformed because of the skewedness of their distribution. Linear regression models (1) adjusted for age and gender, and (2) fully adjusted for age, gender, current alcohol use, body mass index and CD4 counts were used to examine the associations between smoking tobacco or serum cotinine and inflammatory markers. Level of significance was p < 0.05. Among 749 PLWH who were mainly women (79%), the mean age was 38.5 (8.9) years and similar when stratified by smoking status. Serum cotinine levels exhibited a striking discrepancy, with a median of 154 ng/mL among current smokers, in stark contrast to the consistent median values of 10 ng/mL observed among past and never smokers. In regression models adjusted for age and gender, current smoking and frequent smoking were associated with lower IL-2 but higher TNF-α. Log-cotinine exhibited associations with IFN-γ, IL-10, and TNF-α, while cotinine levels ≥ 10 ng/mL compared to < 10 ng/mL were associated with higher IFN-γ and TNF-α. In fully adjusted models, log-cotinine and cotinine levels ≥ 10 ng/mL displayed significant associations with higher IFN-γ and lower IL-2. This study underscores the importance of investigating the interplay between smoking tobacco or serum cotinine levels with pro-inflammatory cytokines in PLWH. It signals the need for comprehensive research to unravel the potential synergistic impacts of smoking tobacco and HIV infection on chronic inflammation and immune dysregulation, shedding light on critical avenues for intervention and management strategies
In vitro neuroprotective effects of boophone disticha, brunsvigia bosmaniae and strumaria truncata extracts in SH-SY5Y cells
No full textParkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. The pathological hallmarks of PD are defined by the loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain, with its characteristic clinical motor and non-motor symptoms. Current treatments for PD are mainly palliative; hence, novel neuroprotective and therapeutic approaches are needed. This study investigated the potential neuroprotective effects of three Amaryllidaceae plant extracts, Boophone disticha, Brunsvigia bosmaniae, and Strumaria truncata, in an in vitro model of PD involving the exposure of SH-SY5Y cell lines to the MPP+ neurotoxin. The protective effects of the three medicinal plants on cell viability were evaluated. The mechanism of the induced neuroprotection was investigated by measuring intracellular reactive oxygen species (ROS) levels, nitric oxide (NO) levels, adenosine triphosphate (ATP) levels, caspase 3 activity, and autophagy levels in the SH-SY5Y cells. The results showed that treatment with the extracts was protective against the toxicity induced by MPP+ in the SH-SY5Y cells. This was demonstrated by the significant increase in cell viability in the MPP+-treated cells, attenuation of intracellular ROS and NO levels, caspase 3 activity, and increased ATP activity. These findings suggest that the three extracts could be sources of novel bioactive agents with possible neuroprotective activities owing to their anti-apoptotic and antioxidant activities. Further studies are recommended to characterise the constituent compounds in these extracts to support their potential as drug discovery and development candidates
Development of seed germination and in vitro propagation protocols for Vitex doniana
No full textPropagation of Vitex doniana by seeds has been limited by low yield and a prolonged germination period which, along with over-harvesting, has led to a decline in its natural population. The present study aimed to improve seed germination and to establish in vitro organogenesis protocols to conserve superior genotypes. The effects of seed pre-treatments and environmental conditions on seed germination were investigated through conventional germination methods. Removal of the seed coat followed by germination on filter paper resulted in the highest percentage germination (87 %). The best germination temperature range was 25 °C-35 °C (80–87 %). A direct organogenesis protocol was established when in vitro nodal explants were cultured for eight weeks on modified Woody Plant Medium (WPM) supplemented with 0.3 mg/L 6-benzylaminopurine (BAP), resulting in 4 shoots/explant. Shoots were rooted on the modified WPM containing 0.5 mg/L indole-3-acetic acid (IAA), resulting in 80 % rooting and 4 roots/shoot, after four weeks. Successful acclimatisation was achieved, with 93 % survival in the greenhouse. For somatic embryogenesis, pro-embryos that formed from pairing 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) with 1 mg/L picloram or each tested auxin with 0.5 mg/L BAP failed to develop into somatic embryos on different maturation media. For time and cost savings and high yield, the present study found that germination be performed using de-coated seeds on filter paper at 25–35 °C followed by transfer to soil upon germination. The present study reports the first direct organogenesis protocol for V. doniana, allowing for clonal propagation of high-value genotypes
Accuracy assessment of vertical and horizontal coordinates derived from Unmanned Aerial Vehicles over District Six in Cape Town
No full textUnmanned aerial vehicles (UAVs) are now an alternative for geospatial data collection for a variety of applications. One such application is terrain mapping, particularly digital elevation model (DEM) and digital surface model (DSM) products, but questions remain about its accuracy and efficiency, especially when compared to traditional ground survey methods. Thus, the purpose of this paper is to compare the traditional surveying methods for topographical mapping through datasets obtained through Total Station (Trimble M3) and a camera mounted on a quadcopter (DJI Phantom 4 Pro UAV). We obtained both datasets in the same location at the District 6 open field area in the City of Cape Town, with undulating terrain. We compared the resultant horizontal coordinates (x and y) and orthometric height (H) at 159 check points (CPs). The drone-based elevations were derived using UAV drone computer vision techniques. In using the UAV drone, the reconstructed camera positions and terrain features were used to derive ultra-high-resolution point clouds, ortho-photos, and digital surface models from the multi-view UAV camera photos taken at 120 m above mean sea level. The root-mean-square-errors (RMSEs) for the differences between the Total Station and UAV coordinates at 159 CPs are ±0.046, ±0.038 and ±0.079 m for x, y, and H coordinates, respectively. Comparisons over slope ranges show that the highest orthometric height error (±0.090 m) is at a slope steepness of >15°, while the least orthometric height error (±0.073 m) is at a slope steepness of 5 - 10°. The results also show that the highest errors in x (±0.070 m) and y (±0.074 m) occur at a slope steepness of >15° and the least errors in x (±0.035 m) and y (±0.029 m) at a 5 – 10° slope steepness. Similar comparisons on elevation ranges show that the highest orthometric height error (±0.098 m) is at an elevation range of 60 – 100 m, while the least orthometric height error (±0.052 m) is at a 40 – 60 m elevation range. The highest errors in x (±0.051 m) and y (±0.061m) occur at elevation ranges of 40 – 60 m and 0 – 20 m, respectively, while the least errors in x (±0.040 m) and y (±0.025 m) occur at elevation ranges of 80 – 100 m and 40 – 60 m, respectively. These results indicate that horizontal positions (x, y) and orthometric heights (H) obtained from UAV are accurate enough for most mapping applications