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DLTS characterisation of 107 MeV krypton ion-irradiated nitrogen-doped 4H-silicon carbide
Full text linkDATA AVAILABILITY : The datasets generated during and/or analysed during the current study are available from the author on reasonable request.Please read abstract in the article.Open access funding provided by University of Pretoria.https://link.springer.com/journal/10854hj2024PhysicsSDG-09: Industry, innovation and infrastructur
Carboxy-amidated AamAP1-lys has superior conformational flexibility and accelerated killing of gram-negative bacteria
Full text linkPlease read abstract in the article.The South African Medical Research Council; the SA-UK Newton Fund Antibiotic Accelerator; the UK Materials and Molecular Modeling Hub for computational resources, which is partially funded by EPSRC and a BBSRC LIDo studentship.https://pubs.acs.org/journal/bichaw?ref=breadcrumbhj2024AnatomyBiochemistry, Genetics and Microbiology (BGM)SDG-03:Good heatlh and well-bein
Deconstructing a single-actor resource ownership model : a study of the proposed uranium mining in the Karoo region of South Africa
Full text linkThis study engages the discourse of ‘eminent domain’ – the power of the state to expropriate communally or individually owned properties for ‘public good’ – as it applies in the mineral extractive sector in resource-rich countries, such as South Africa. It is argued that the use of the ‘eminent domain’ principle in the acquisition of land and allocation of mining rights reinforces the notion of the ‘supreme state’. The entrenchment of this idea advances ‘the single metric model’ in which one stakeholder's voice is heard at the expense of other stakeholders. This hierarchical framework privileges the state and the licensed mining companies and excludes resource-rich communities and other egalitarian structures. It is against this backdrop that this study makes a case for the deconstruction of a ‘single-actor resource ownership’ model in South Africa. Using data collected through qualitative instruments, the study concluded that the ‘single metric’ approach, in which the state enforces its agency over the other stakeholders, is rooted in its understanding of ‘rights and sovereignty’ over land and mineral resource ownership in South Africa. This strikes at the centre of a developing conflict among the stakeholders in the uranium-rich community. Therefore, the disaggregation of the current unconstructive policy space dominated by the hierarchic state to one which accommodates diverse views and voices of other stakeholders will create a multi-metric, pluralistic and democratic environment where the ‘public-use principle’ in essence does not exclude the public.https://www.elsevier.com/locate/exishj2024SociologySDG-16:Peace,justice and strong institution
Monetary policy shocks and multi-scale positive and negative bubbles in an emerging country : the case of India
Full text linkAVAILABILITY OF DATA AND MATERIALS : Data will be made available upon request.We employ the Multi-Scale Log-Periodic Power Law Singularity Confidence Indicator (MS-LPPLS-CI) approach to identify positive and negative bubbles in the short-, medium, and long-term for the Indian stock market, using weekly data from November 2003 to December 2020. We use a nonparametric causality-in-quantiles approach to analyze the predictive impact of monetary policy shocks on bubble indicators. We find, in general, strong evidence of predictability across the entire conditional distribution for the two monetary policy shock factors, with stronger impacts for negative bubbles. Our findings have critical implications for the Reserve Bank of India, academics, and investors.https://jfin-swufe.springeropen.comhj2024EconomicsSDG-08:Decent work and economic growt
Application of behavior change techniques (BCTTv1) to reduce antimicrobial use in livestock : a scoping review
Full text linkDATA AVAILABILITY STATEMENT : All data supporting the findings of this study are included in this article.SUPPLEMENTARY MATERIAL : TABLE S1: Summary of behavior change techniques (BCTs) utilized in on-farm antimicrobial reduction interventions, with examples and supporting authors.SIMPLE SUMMARY : This research explores how behavior change techniques can help reduce antibiotic use in farm animals. The overuse of antibiotics in livestock contributes to antimicrobial resistance, making infections harder to treat in both animals and humans. The study reviews how these techniques have been used to encourage farmers to use fewer antibiotics and identifies areas in which more research is needed. Some effective approaches include setting goals, learning from experts, problem-solving, receiving feedback, and self-monitoring. However, the success of these techniques depends on factors like cost, farm conditions, cultural practices, and education. Many studies do not clearly describe how they apply these techniques, limiting opportunities to refine and replicate successful interventions. To improve antibiotic reduction efforts, future programs should focus on clear documentation, long-term support, and region-specific solutions. Collaboration between veterinarians, farmers, researchers, and policymakers is key to ensuring lasting improvements. More attention is needed in developing countries where antibiotic reduction efforts are limited. Encouraging responsible antibiotic use through behavior change techniques will help slow resistance, assure food safety, protect public health, and improve animal welfare worldwide.Antimicrobial resistance (AMR) is a critical global health threat, partly driven by the overuse of antimicrobials in livestock production. Addressing this issue requires targeted interventions to influence behavioral drivers behind AMU practices. Behavior change techniques (BCTs) offer a structured approach to designing such interventions, yet their application in reducing AMU on farms remains underexplored. This scoping review systematically maps the current applications of the Behavior Change Techniques Taxonomy version 1 (BCTTv1) in interventions aimed at reducing AMU in livestock, while also identifying gaps in the literature and opportunities for future research. A comprehensive search across academic databases identified 23 relevant studies. Findings revealed the use of 37 BCTs, with commonly applied techniques including goal setting, instruction on behavior, credible sources, problem-solving, feedback on behavior, and self-monitoring. While some studies explicitly referenced BCTs, many applied them implicitly, without alignment with standardized frameworks. Intervention outcomes were influenced by contextual factors including financial, logistical, cultural, and technical challenges. This review underscores the importance of explicitly integrating and systematically reporting BCTs to enhance transparency, replicability, and scalability. Future interventions should adopt tailored, context-specific approaches to address regional and sectoral challenges, ultimately contributing to global efforts in combating AMR through improved antimicrobial stewardship.https://www.mdpi.com/journal/vetscihj2024Veterinary Tropical DiseasesSDG-02:Zero HungerSDG-03:Good heatlh and well-bein
Glioblastoma cells alter brain endothelial cell homeostasis and tight junction protein expression in vitro
Full text linkDATA AVAILABILITY : Data is provided within the manuscript or supplementary information files.BACKGROUND : Glioblastoma (GBM) is an aggressive therapy-resistant brain tumour that may impacts the integrity of the blood–brain barrier (BBB). The BBB is a protective barrier of the central nervous system formed mainly by endothelial cells. This study aimed to investigate the in vitro effect of GBM cells on the BBB.
METHODS : Brain endothelial (bEnd.3) cells were used as a model of the BBB. Glioblastoma-conditioned media (CM) was extracted at the 48-h (h) time-point from the U87 GBM cells and diluted to 40% with fresh media. The effect of the U87-CM collected at 48 h on bEnd.3 cell growth was evaluated following 48 and 72 h of treatment using the xCELLigence system. Additionally, bEnd.3 cell growth was also investigated in a U87 and bEnd.3 co-culture model continuously for 48 h using the xCELLigence system. The migration of bEnd.3 cells was assessed following 48 and 72 h using the migration scratch assay. The barrier integrity was evaluated continuously for 1 h using the transwell permeability, and the tight junction (TJ) protein expression was evaluated using Western blot assay following 48 and 72 h.
RESULTS : There was a significant decrease in bEnd.3 cell growth following 32 h (p < 0.05), 40 h (p < 0.01), and 48 h (p < 0.001) of treatment with U87-CM, while co-culturing of bEnd.3 and U87 cells increased cell growth following 16 h (p < 0.05), 24 h (p < 0.001), 32 h (p < 0.01), 40 h (p < 0.001), and 48 h (p < 0.001). The migration of bEnd.3 cells significantly increased following both 24 (p < 0.05) and 48 h (p < 0.01) of treatment with U87-CM. The permeability of bEnd.3 cells co-cultured with U87 for 48 h was significantly increased (p < 0.05) at the 15- and 30-min time points. Furthermore, the expression of ZO-1 and occludin was significantly increased (p < 0.05) in both bEnd.3 cells treated with U87-CM as well as bEnd.3 cells co-cultured with U87 cells.
CONCLUSION : The current findings suggest that U87 cells alter the integrity of bEnd.3 cells possibly through the secretomes in the CM and through cell–cell interactions in co-culture models. This may assist in the understanding of the mechanisms by which GBM affects the BBB, which may aid in the management thereof.The South African Medical Research Council Self-Initiated Research (SAMRC-SIR) grant, and the University of Pretoria’s Research Development Programme (RDP) and RESCOM grants, and the article processing charges were funded by the Department of Pharmacology, University of Pretoria.https://link.springer.com/journal/11060hj2024PharmacologyPhysiologySDG-03:Good heatlh and well-bein
Can a cochlear implant be used as an electrical impedance tomography device?
Full text linkDATA AVAILABILITY STATEMENT :
Data sharing is not applicable to this article as no new data were created or analyzed in this study.The imaging of the live cochlea is a challenging task. Regardless of the quality of images obtained from modern clinical imaging techniques, the internal structures of the cochlea mainly remain obscured. Electrical impedance tomography (EIT) is a safe, low-cost alternative medical imaging technique with applications in various clinical scenarios. In this article, EIT is investigated as an alternative method to image and extract the centre of gravity of the modiolus in vivo. This information can be used to augment present postoperative medical imaging techniques to investigate the cochlea. The cochlear implant EIT system was simulated by modelling user-specific electrode array trajectories within a simple conductive medium containing an inhomogeneity representing the modiolus. The method included an adapted adjacent stimulation protocol for data collection. For the image reconstruction, NOSER and Tikhonov priors were considered. A parameter analysis was conducted to find the most robust combination of image priors and hyperparameters for this application. The cochlear implant EIT methodology was validated at different noise levels for four electrode array trajectories. Comparing the NOSER and Tikhonov priors, it was observed that the NOSER prior exhibits superior centre of gravity localisation performance in cochlear implant EIT image reconstruction for different noise levels and user-dependent variability in electrode array trajectories. Image reconstruction, using a NOSER prior at a hyperparameter value of approximately 0.001, resulted in an average centre of gravity localisation error of less than 4% for all electrode array trajectories using difference imaging and less than 5.5% using absolute imaging.The National Research Foundation of South Africa.https://onlinelibrary.wiley.com/journal/20407947hj2024Electrical, Electronic and Computer EngineeringSDG-03:Good heatlh and well-beingSDG-09: Industry, innovation and infrastructur
Accuracy of approximate methods for the calculation of fluorescence-type linear spectra with a complex system-bath coupling
Full text linkDATA AVAILABILITY STATEMENT : Data is available on reasonable request from the authors.Much can be learned about molecular aggregates by modeling their fluorescence-type spectra. In this study, we systematically describe the accuracy of various methods for simulating fluorescence-type linear spectra in a dimer system with a complex system–environment interaction, which serves as a model for various molecular aggregates, including most photosynthetic light-harvesting complexes (LHCs). We consider the approximate full cumulant expansion (FCE), complex time-dependent Redfield (ctR), time-independent Redfield, and modified Redfield methods and calculate their accuracy as a function of the site energy gap and coupling, excitonic energy gap, and dipole factor (i.e., type of spectrum). We find that the FCE method is the most accurate method for couplings smaller than 300 cm−1 at 300 K, but this method fails for very strong couplings or low temperatures due to inaccurate modeling of the equilibrium initial state. The ctR method performs well for the calculation of fluorescence and linear anisotropy spectra but poorer for circularly polarized fluorescence spectra or for all spectra when the coupling is strong . The Redfield and modified Redfield methods generally perform much more poorly than the ctR and FCE methods—especially for small excitonic energy gaps and strong couplings. We show that accurate modeling of the Stokes shift is crucial and present a version of the ctR method that treats both the Stokes shift and initial state correctly for the parameter ranges in plant LHCs. Apart from the application to LHCs, our results will be useful for the spectral characterization and design of organic molecular aggregates.The South African National Research Foundation; South African Quantum Technology Initiative; the Department of Research
and Innovation of the University of Pretoria; the National Laser Centre Rental
Pool Programme; the
Czech Science Foundation.https://aip.scitation.org/journal/jcphj2024PhysicsSDG-09: Industry, innovation and infrastructur
Exploring network typology and their role in immigrant entrepreneurship: insights from South Africa
Full text linkPURPOSE :
This study aims to explore network typology and the role of networks in immigrant entrepreneurs’ (IEs) business operations in South Africa (SA).
DESIGN/METHODOLOGY/APPROACH :
In-depth interviews were carried out with 25 IEs operating their business ventures in SA, selected via the purposive sampling method.
FINDINGS :
The findings indicated that IEs in SA use social networks most often, with minimal use of international business networks. In addition, the findings showed that IE networks’ key roles include providing them with access to referrals and resource provision. However, whilst resource provision emerged as a significant role, finance appeared as the main resource provided by networks.
ORIGINALITY/VALUE :
To the best of the authors’ knowledge, this original paper provided theoretical and empirical contributions to research on network typology and its role for IEs. Thus, the study extended the current literature on the intersection of IEs and their networking behaviours.https://www.emerald.com/insight/publication/issn/1750-6204hj2024Business ManagementSDG-08:Decent work and economic growt
Helen Verran and the question of African logic
No full textHitherto, the African intellect had been decimated by notable European scholars such as David Hume, Charles Darwin, Friedrich Hegel, Lucien Levy-Bruhl to name a few. The common denominator among these male scholars is that the African intellect is not yet developed to the extent that it can accommodate logical reasoning. Whereas notable African scholars have responded to these charges as misleading whilst exploring ways of coming up with a logic system that can mediate the theory, thought and practice peculiar to Africans yet applicable in other climes, the role of women in this journey has usually been downplayed. This research thereby seeks to fill this void by making a case for the contribution of the Australian Helen Verran who did not engage in armchair scholarship as most of her European male counterparts who deny the African the ability to reason logically, but journeyed to Nigeria to perform some experiments with the Yorùbá numerical system. She is persuaded that through the traditional Yorùbá numerical pattern, an underlying logic system is implied. Even when her conclusions are questionable on several fronts, this research concludes that her role in instilling confidence in the development of artificial logic in Africa must not go unmentioned.https://www.tandfonline.com/journals/thpl202025-12-09hj2024PhilosophyNon