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Magnetohydrodynamics of nanofluid internal forced convection : a review and outlook for practical applications
Full text linkDATA AVAILABILITY : Data will be made available on request.Please read abstract in the article.The Technology Innovation Agency (TIA), an implementing entity of the RSA Department of Science and Technology.https://www.elsevier.com/locate/rinphj2024Mechanical and Aeronautical EngineeringSDG-09: Industry, innovation and infrastructur
Improving the activity and selectivity of a scorpion-derived peptide, A3a, against Acinetobacter baumannii through rational design
Full text linkThe rise in antimicrobial resistance has led to an increased desire to understand how antimicrobial peptides (AMPs) can be better engineered to kill antibiotic-resistant bacteria. Previously, we showed that C-terminal amidation of a peptide, identified in scorpion Androctonus amoreuxi venom, increased its activity against both Gram-positive and -negative bacteria. Here, we incorporate all-atom molecular dynamics (MD) simulations in a rational design strategy to create analogues of A3a with greater therapeutic potential. We discover two novel AMPs which achieve greater potency against, and selectivity toward, Acinetobacter baumannii ATCC 19606 but via two distinct mechanisms and which are effective in Galleria mellonella models of A. baumannii burn wound infection. While CD spectroscopy indicates A3a adopts an α-helix conformation in the presence of models of the Gram-negative bacterial plasma membrane, MD simulations reveal it adopts a hairpin conformation during initial binding. Three different strategies, designed to stabilize this hairpin conformation, produce substantially different outcomes. Deletion of Ile6 and Ile10 restricts conformational flexibility, characteristic of A3a, during membrane binding, prevents adoption of the α-helix conformation in the steady state, and abrogates the antibacterial activity. In contrast, substitution of arginine 7 to lysine (A3a[R7K]) or isoleucine 14 to tryptophan (A3a[I14W]) does not consistently affect peptide conformations. Both of these new analogues are rapidly bactericidal toward A. baumannii ATCC 19606 but A3a[R7K] also causes rapid permeabilization and while the antibacterial potency and selectivity are increased for both peptides, this is greatest for A3a[I14W]. Integration of atomistic MD simulations into a multidisciplinary approach to understanding antimicrobial peptide mechanism of action is a valuable tool for interpreting the effects of rational design strategies.The South African Medical Research Council, with funds received from the South African National Department of Health and a SA-UK Newton Fund Antibiotic Accelerator.https://pubs.acs.org/journal/acsodf?ref=breadcrumbhj2024Biblical and Religious StudiesBiochemistry, Genetics and Microbiology (BGM)SDG-15:Life on lan
Assessing the feasibility of mapping changes of ecosystem functional groups in South African estuaries using Landsat and Sentinel images of 1990, 2014, 2018 and 2020
Full text linkDATA AVAILABILITY : Available on request.This study evaluates the feasibility of using medium-resolution satellite sensors to monitor changes in the extent of ecosystem functional groups (EFGs) in South African estuaries, for reporting on the 2030 targets of the Global Biodiversity Framework (GBF). Landsat and Sentinel-1 and -2 image collections in Google Earth Engine (GEE) were used to generate output layers for each of the national land cover years—1990, 2014, 2018 and 2020. Image composites of each year’s two growth seasons and one dry season, vegetation indices and topographic data were generated. Changes in the extent and accuracies of three estuarine (mangroves, salt marshes and submerged macrophytes) and three freshwater (forested wetlands, freshwater marshes and large macrophytes) EFGs were calculated and compared to a manually mapped through image interpretation, high-confidence layer. Overall, estuarine EFGs comprised between 10 and 18% of the extent of the EFGs, while freshwater EFGs made up 15% of the extent of estuaries. The overall accuracies of detection of EFGs for 1990 were 71% attained for 2014, 2018 and 2020. In comparison to manual delineations of some of these habitats, the outputs generated from these medium-resolution sensors resulted in overestimation of extent for all EFGs; for mangroves by 115% and for salt marshes and submerged macrophytes by 150–230%. Finer spatial resolution images, and time-series mapping would be critical for improved delineation and monitoring of South Africa’s estuarine habitats.The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH, through the implemented Climate Support Programme, as part of the International Climate Initiative (IKI). The German Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV) supports the IKI on the basis of a decision adopted by the German Bundestag. Open access funding provided by Council for Scientific and Industrial Research.https://link.springer.com/journal/11273hj2024Geography, Geoinformatics and MeteorologySDG-14:Life below waterSDG-15:Life on lan
Regional adaptation of integrated pest management to control invasive forest insects
Full text linkDATA AVAILABITY STATEMENT: Anonymized survey results are available on Zenodo at https://doi.org/10.5281/zenodo.13749152 (Stastny et al. 2024).Globalization is increasing the threat of invasive forest insects to ecosystems. Control efforts against the same pest species progressively occur across distant jurisdictions as integrated pest management (IPM) programs or tactics developed in one region are
adopted by another region. This knowledge exchange accelerates responses and collaboration; however, transplanted IPM programs can overlook preexisting or emerging differences between regions, which may explain their varying success. These differences include biological variation in the pest system, environmental conditions, issues of scale and capacity of the response, regulatory environment, and cultural context. We examine the role of these factors in the adoption and outcomes of IPM programs,
drawing from case studies and an online survey of forestry IPM experts. To facilitate regional adaptation of IPM programs during
their adoption and implementation in new regions, we propose an evaluation framework and recommend approaches to not only
reduce risks but also maximize uptake, efficacy, and resilience.https://esajournals.onlinelibrary.wiley.com/journal/15409309Forestry and Agricultural Biotechnology Institute (FABI)Zoology and EntomologySDG-15:Life on landSDG-17:Partnerships for the goal
Forecasting multivariate volatilities with exogenous predictors : an application to industry diversification strategies
No full textWe propose a procedure to forecast the realized covariance matrix for a given set of assets within a multivariate heterogeneous autoregressive (MHAR) framework. Utilizing high-frequency data for the U.S. aggregate and industry indexes and a large set of exogenous predictors that include financial, macroeconomic, sentiment, and climate-based factors, we evaluate the out-of-sample performance of industry portfolios constructed from forecasted realized covariance matrices across various univariate and multivariate forecasting models. Our findings show that LASSO-based multivariate HAR models employing predictors that capture climate uncertainty generally yield more consistent evidence regarding the accuracy of the realized covariance forecasts, providing further support for the growing evidence that climate related factors significantly drive return and volatility dynamics in financial markets. While international summits and global warming stand out as the dominant climate predictors for realized volatility forecasts, both climate and macroeconomic predictors prove equally important for longer term correlation forecasts. In these forecasts, the U.S. EPU index and natural disasters, along with U.S. climate policy uncertainty, play dominant predictive roles. Our results suggest that the MHAR framework, coupled with DRD decomposition that splits the covariance matrix into a diagonal matrix of realized variances and realized correlations, can be utilized in a high-frequency setting to implement diversification and smart beta strategies for various investment horizons.The National Natural Science Foundation of China, the General Project of Social Science Planning in Guangdong Province, Guangzhou Municipal Science and Technology Bureau and Natural Science Foundation of Guangdong Province, Fundamental Research Funds for the Central Universities.https://www.elsevier.com/locate/jempfin2026-08-04hj2024EconomicsSDG-08:Decent work and economic growt
Bioactivity of plants used traditionally in the treatment and management of men's sexual health
Full text linkThis article is partially based on the author’s, T.N., thesis
entitled ‘Biological evaluation of ethnobotanical selected
medicinal plants used in the management of male sexual
health’ towards a PhD in Life Sciences in the School of
Agriculture and Life Sciences, University of South Africa,
South Africa, 2023, with supervisors Prof. T.E. Tshikalange
and Dr M.A. Nyila. It is available here: https://uir.unisa.
ac.za/handle/10500/31271?show=full.DATA AVAILABILITY : The data that support the findings of this study are
available on reasonable request from the corresponding
author, T.E.T.Please read abstract in the article.The National Research Foundation, University of South Africa and University of Pretoria.http://www.jomped.org/hj2024Plant Production and Soil ScienceSDG-03:Good heatlh and well-beingSDG-15:Life on lan
Sectoral corporate profits and long-run stock return volatility in the United States : a GARCH-MIDAS approach
Full text linkDATA AVAILABILITY STATEMENT : The data supporting this study's findings are available on request from the corresponding author. However, the data are not publicly available due to privacy or ethical restrictions.This study aims to examine the usefulness of corporate profits in predicting the return volatility of sectoral stocks in the United States. We use a GARCH-MIDAS approach to keep the datasets in their original frequencies. The results show a consistently positive slope coefficient across various sectoral stocks. This implies that higher profits lead to increased trading of stocks and, subsequently, a higher volatility in the long run than usual. Furthermore, the analysis also extends to predictability beyond the in-sample. We find strong evidence that corporate profits can predict the out-of-sample long-run return volatility of sectoral stocks in the United States. These findings are significant for investors and portfolio managers.https://onlinelibrary.wiley.com/journal/1099131xhj2024EconomicsSDG-08:Decent work and economic growt
Synthesis and SAR studies of acyl-thiourea platinum(II) complexes yield analogs with dual-stage antiplasmodium activity
Full text linkMixed-ligand platinum(II) complexes incorporating bipyridine and acyl-thiourea ligands were synthesized and evaluated for their in vitro growth inhibitory activity against the human malaria parasite Plasmodium falciparum (Pf). The substituents at four distinct sites were varied to identify structure–activity relationships for this series. Most complexes displayed potent PfNF54 activity with IC50 values in the nanomolar range and favorable cytotoxicity profiles. Five complexes (C1, C11, C12, C15, and C17) exhibited activity against both the asexual blood and sexual (gametocyte) stage parasites, with another complex (C8) exhibiting activity against late-stage gametocytes only. In addition, the complexes showed comparable ABS potency against the PfK1 multidrug-resistant strain. The pharmacokinetic parameters of one analog (C6), which displayed good solubility and mouse microsomal metabolic stability, were measured. This work demonstrates the potential of acyl-thiourea platinum(II) complexes as selective, multistage-active antiplasmodium compounds as part of the search for new antimalarial agents.The South African Medical Research Council and the South African Research Chairs Initiative of the Department of Science and Technology administered through the South African National Research Foundation; an NRF Community of Practice on “Evaluating Malaria Control Interventions” and the National Institute of Allergy and Infectious Diseases, National Institutes of Health.https://pubs.acs.org/journal/amclct?ref=breadcrumbhj2024Biochemistry, Genetics and Microbiology (BGM)UP Centre for Sustainable Malaria Control (UP CSMC)SDG-03:Good heatlh and well-bein
A novel study on chronoamperometry electrodeposition of hexagonal boron nitride with Eucalyptus grandis-derived activated carbon for supercapacitor applications
No full textDATA AVAILABILITY : Data will be made available on request.Activated carbon (AC) and hexagonal boron nitride (hBN) electrodes were successfully synthesized from Eucalyptus grandis tree bark and a mixture of boric acid and urea in the ratio of 2:3, respectively. The optimal composite hBN/AC-1:0.05 electrode was prepared by chronoamperometry electrodeposition at an optimal potential of 0.45 V for 60 min. The prepared electrodes were analyzed using Raman spectroscopy, Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive X-ray spectroscopy (EDS). Half- and full-cell setups were used to investigate the as-prepared AC, hBN, and hBN/AC composite electrodes in 3 M KOH for electrochemical characterization. A supercapacitor was assembled using hBN/AC-1:0.05//AC. The device displayed a specific energy of 24.1 Wh/kg and a corresponding specific power of 1025 W/kg at 1 A/g in a potential window of 1.6 V. Furthermore, the developed device demonstrated a coulombic efficiency of 99.4 % and a capacity retention of 76.3 % after 10,000 GCD cycles at 5 A/g. The results of hBN/AC-1:0.05//AC contribute to the scientific community by highlighting the importance of biomass recycling (Eucalyptus grandis tree bark) and providing a simple approach to producing a composite material for energy storage.The Partnership for skills in Applied Sciences, Engineering, and Technology (PASET) for offering the Regional Scholarship and Innovation Fund (RSIF).https://www.elsevier.com/locate/est2025-12-17hj2024PhysicsSDG-07:Affordable and clean energySDG-09: Industry, innovation and infrastructur
Mapping tree canopy thermal refugia for birds using biophysical models and LiDAR
Full text linkDATA AVAILABILITY :
The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.Please read abstract in the article.The National Research Foundation of South Africa. The LiDAR data collection and processing was funded by Harvard University. Open access funding provided by University of Pretoria.https://link.springer.com/journal/484hj2024Plant Production and Soil ScienceZoology and EntomologySDG-13:Climate actionSDG-15:Life on lan