Research Articles (University of Pretoria)

Permanent URI for this collectionhttp://hdl.handle.net/2263/121

This collection offers open access to the full text of research articles published by staff, students and affiliates of the University of Pretoria. These items are identical in content to their published counterparts. It is linked to the Research Information System and complements the Annual Research Report.

Access to the full text of UP theses and dissertations is available at UP Electronic Theses and Dissertations.

Information and guidelines for authors/ submitters available at http://www.ais.up.ac.za/openup/index.htm.

For inquiries regarding this collection or items in the collection, please contact : Hendriette Jansen van Vuuren
Tel.: +27 12 420 4712

Browse

Now showing 1 - 20 of 40462

Supporting re-engagement with HIV services after treatment interruption in South Africa : a mixed method program evaluation of MSF’s Welcome Service
(Nature Research, 2024-03-27) Arendse , Kirsten D.; Walker , Caroline; Pfaff , Colin; Lebelo , Keitumetse; Cassidy, Tali; Isaakidis , Petros; Von der Heyden, Erin; Abdullah, Fareed; Ellman , Tom; Katz , Ingrid T.; Euvrard, Jonathan; Keene, Claire M.
Psychosocial challenges impact patients' ability to remain on antiretroviral therapy lifelong, magnified by disorganized health-systems and healthcare worker (HCW) attitudes. To address this, Médecins Sans Frontières and the Department of Health developed the Welcome Service intervention, to provide person-centered care at re-engagement after HIV treatment interruption. Implemented in Khayelitsha, South Africa, between August 2020 and February 2021, the intervention aimed to reorganize triage, optimize clinical and counselling services and address HCW attitudes. The study used a mixed-methods design, incorporating in-depth interviews, and analyses of programmatic and routine health data. Interviews demonstrated positive patient care experiences. HCWs understood the potential impact of attitudes on patient engagement, however, some continued to demonstrate judgmental attitude. Clinical objectives were variably met at re-engagement: 98% were re-initiated the same day, 50% had a CD4 done, and 45% received tuberculosis prevention. Nevertheless, 4-month retention was 66%, and 88% had a VL < 1000 c/mL. Despite HCWs' understanding of person-centered care not translating into supportive behaviors, patients had positive care experiences and the intervention ended with a high rate of VL suppression. More efforts are needed to design interventions building on Welcome Service principles to provide person-centered care and sustain retention after re-engagement.
Routine upper gastro-intestinal tract endoscopy before elective cholecystectomy for symptomatic gallstones-justified
(Nature Research, 2024-06-18) Morrison, Sherwyn; Mokoena, Taole; taole.mokoena@up.ac.za
Gallstones are common in Western countries and increasing in developing countries through adoption of western lifestyle. Gallstones may cause life-threatening complications, including acute cholecystitis, acute cholangitis, and acute pancreatitis. Cholecystectomy is the treatment of choice for symptomatic gallstones. Presentation of symptomatic gallstones may be indistinguishable from that of other upper gastro-intestinal tract (UGI) pathologies. Some surgeons routinely perform preoperative UGI endoscopy to diagnose and treat concomitant UGI pathology. A prospective cross-sectional observational study was undertaken at University of Pretoria teaching hospitals to evaluate this practice. Patients aged 18 years and older, with symptomatic gallstones but did not satisfy Tokyo guidelines for acute cholecystitis were recruited. UGI endoscopy was performed before cholecystectomy. There were 124 patients, 110 (88.7%) females and 14 (11.3%) males, mean age 44.0 (13.2) (range: 22–78) years. Most common symptoms were right upper quadrant (RUQ) pain (87%), epigastric pain (59.7%), nausea (58.1%) and vomiting (47.9%). Clinically, 80% had RUQ tenderness and 52.4% epigastric tenderness. UGI endoscopy found 35.4% pathology, 28.2% were active, and comprised acute gastritis (27.4%), peptic ulcers (4.8%), duodenitis (3.2%) and oesophagitis (2.4%). Twelve patients had more than one pathology. This warranted treatment before elective cholecystectomy and justifies the practice of routine preoperative UGI endoscopy.
Population changes in a Southern Ocean krill predator point towards regional Antarctic sea ice declines
(Nature Research, 2024-10-28) Germishuizen, Matthew; Vichi, Marcello; Vermeulen, Els; u15029507@tuks.co.za
While foraging, marine predators integrate information about the environment often across wide-ranging oceanic foraging grounds and reflect these in population parameters. One such species, the southern right whale (Eubalaena australis; SRW) has shown alterations to foraging behaviour, declines in body condition, and reduced reproductive rates after 2009 in the South African population. As capital breeders, these changes suggest decreased availability of their main prey at high-latitudes, Antarctic krill (Euphausia superba). This study analysed environmental factors affecting prey availability for this population over the past 40 years, finding a notable southward contraction in sea ice, a 15–30% decline in sea ice concentration, and a more than two-fold increase in primary production metrics after 2008. These environmental conditions are less supportive of Antarctic krill recruitment in known SRW foraging grounds. Additionally, marginal ice zone, sea ice concentration and two primary production metrics were determined to be either regionally significant or marginally significant predictors of calving interval length when analysed using a linear model. Findings highlight the vulnerability of recovering baleen whale populations to climate change and show how capital breeders serve as sentinels of ecosystem changes in regions that are difficult or costly to study.
Pheromonal variation and mating between two mitotypes of fall armyworm (Spodoptera frugiperda) in Africa
(Nature Research, 2024) Sisay, Birhanu; Tamiru, Amanuel; Subramanian, Sevgan; Weldon, Christopher William; Khamis, Fathiya; Green, Kristina Karlsson; Anderson, Peter; Torto, Baldwyn
In the Americas, the fall armyworm (Spodoptera frugiperda) exists in two genetically distinct strains, the corn (C) and rice (R) strains. Despite their names, these strains are not associated with host plant preferences but have been shown to vary in pheromone composition and male responses. Recently, S. frugiperda was detected in Africa as an invasive species, but knowledge about variation in strain types, pheromone composition and inter-strain mating of populations of the pest in the continent has not been fully examined. Therefore, this study aimed to investigate variations, if any in the pheromone composition of female moths, male moth responses, and mating between C and R mitotypes of S. frugiperda populations in Kenya, as well as their geographic distribution. Strains (mitotypes) of S. frugiperda were identified using mitochondrial DNA (mtDNA) markers, and their pheromonal composition determined by coupled gas chromatography-mass spectrometric (GC-MS) analysis. Male moth responses to these compounds were evaluated using GC-electroantennographic detection (EAD), electroantennogram (EAG), and wind tunnel assays. Oviposition assays were used to determine whether R and C mitotype moths could mate and produce eggs. The results showed that both the R and C mitotypes were present, and there were no statistically significant differences in their distribution across all sampled locations. Five pheromone compounds including (Z)-7-dodecenyl acetate (Z7-12:OAc), (Z)-7-tetradecenyl acetate (Z7-14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (Z)-11-hexadecenyl acetate (Z11-16:OAc), were detected in the pheromone glands of female moths of both mitotypes, with Z9-14:OAc being the most abundant. The relative percentage composition of Z9-14:OAc was similar in both mitotypes. However, the R mitotype had a 2.7 times higher relative percentage composition of Z7-12:OAc compared to the C mitotype moth, while the C mitotype moth had a 2.4 times higher relative percentage composition of Z11-16:OAc than the R mitotype moth. Male moths of both mitotypes exhibited similar responses to the pheromone compounds, showing the strongest responses to Z9-14:OAc and Z7-12:OAc in electrophysiological and behavioural assays. There was mating between R and C mitotypes with egg production comparable to mating within the same mitotype. Our results revealed that differences between the two S. frugiperda mitotypes are characterized by female moth pheromone composition rather than male moth responses to the pheromones, and that this does not prevent hybridisation between the mitotypes, which may have implications for their management.
The development of a nurse-led preoperative anaesthesia screening tool by Delphi consensus
(South African Medical Association NPC, 2024-02) Nejthardt, M.B.; Alexandris, P.; Bechan, S.; Bijli, M.F.A.; Chetty, S.; Dippenaar, Johannes Marthinus (Tinus); Gibbs, M.W.; Johnson, M.; Kluyts, H.; Llewellyn, R.; Motiang, M.; Mogane, P.; Motshabi, P.; Mrara, B.; Roodt, F.; Singh, U.; Spijkerman, S.; Turton, E.; Van der Westhuizen, J.; Biccard, B.M.; Alexandris, Paula-Josefina
BACKGROUND : Low- and middle-income countries have a critical shortage of specialist anaesthetists. Most patients arriving for surgery are of low perioperative risk. Without immediate access to preoperative specialist care, an appropriate interim strategy may be to ensure that only high-risk patients are seen preoperatively by a specialist. Matching human resources to the burden of disease with a nurse-administered pre-operative screening tool to identify high-risk patients who might benefit from specialist review prior to the day of surgery may be an effective strategy. OBJECTIVE : To develop a nurse-administered preoperative anaesthesia screening tool to identify patients who would most likely benefit from a specialist review before the day of surgery, and those patients who could safely be seen by the anaesthetist on the day of surgery. This would ensure adequate time for optimisation of high-risk patients preoperatively and limit avoidable day-of-surgery cancellations. METHODS : A systematic review was conducted to identify preoperative screening questions for use in a three-round Delphi consensus rocess. A panel of 16 experienced full-time clinical anaesthetists representing all university-affiliated anaesthesia departments in South Africa participated to define a nurses’ screening tool for preoperative assessment. RESULTS : Ninety-eight studies were identified, which generated 79 questions. An additional 14 items identified by the facilitators were added to create a list of 93 questions for the first round. The final screening tool consisted of 81 questions, of which 37 were deemed critical to identify patients who should be seen by a specialist prior to the day of surgery. CONCLUSION : A structured nurse-administered preoperative screening tool is proposed to identify high-risk patients who are likely to benefit from a timely preoperative specialist anaesthetist review to avoid cancellation on the day of surgery.
Prevalence of and factors associated with HIV testing among adolescent girls and young women in South Africa : evidence from the South Africa demographic and health survey 2016
(South African Medical Association NPC, 2024-06) Manamela, M.F.; Musekiwa, Alfred; Twabi, Halima Sumayya; u15336132@tuks.co.za
BACKGROUND : Adolescent girls and young women (AGYW) remain vulnerable to HIV, with a higher incidence rate than their male counterparts. OBJECTIVES : To determine the prevalence of and factors associated with HIV testing among AGYW in South Africa (SA). METHODS : A cross-sectional design was used to analyse the South Africa Demographic and Health Survey 2016. Only sexually active AGYW aged 15 - 24 years residing in SA at the time of the survey were included. Descriptive statistics were used to analyse baseline sociodemographic characteristics. Univariate and multivariate logistic regression models were used to determine factors associated with HIV testing. Statistical significance was set at p<0.05, and all analyses were adjusted using survey weights to account for unequal selection probabilities. RESULTS : The overall prevalence of HIV testing among sexually active AGYW was 85.2% (95% confidence interval (CI) 83.0 - 87.1). The AGYW who had a history of pregnancy (adjusted odds ratio (aOR) 4.47; 95% CI 2.90 - 6.89), were employed (aOR 3.29; 95% CI 1.75 - 6.21), belonged to a middle wealth index (aOR 1.80; 95% CI 1.04 - 3.10), had knowledge about mother-to-child transmission of HIV (aOR 3.29; 95% CI 2.26 - 4.79), had visited a health facility during the past 12 months (aOR 2.93; 95% CI 2.09 - 4.10), or had secondary/tertiary education (aOR 2.04; 95% CI 1.04 - 3.99) had higher odds of HIV testing. CONCLUSION : The study identified an unmet need for HIV testing among sexually active AGYW in SA, especially adolescent girls aged 15 - 19 years. Increasing knowledge about HIV testing, adolescent-friendly services and other offsite strategies are therefore important for this particular key population.
Renal transplant recipient and deceased-donor risk profiles at Wits Donald Gordon Medical Centre, Johannesburg, South Africa
(South African Medical Association NPC, 2024-03) Van der Schyff, F.; Barnard, M.; Strobele, B.; De Jager, M.; Britz, Retha Margaretha; Gaylard, P.; Loveland, J.; De Jager, M.B.; Barnard, M.B.
BACKGROUND : Renal transplantation is the gold-standard therapy for end-stage renal disease. Decision-making around the acceptance of deceased-donor organs is complex and time sensitive. Risk scoring systems for both donors and recipients attempt to simplify the allocation of renal grafts to the most appropriate recipient. OBJECTIVES : To investigate the role of these transplant risk scores in the South African (SA) setting. METHODS : A total of 188 adult deceased-donor organ referrals over the 9-year period 1 January 2013 - 31 December 2021 were included. The Kidney Donor Risk Index (KDRI) and the UK KDRI were calculated for each donor. Recipients who were allocated these grafts were characterised, and the Hennepin Transplant Risk Score and the Kidney Transplant Morbidity Index (KTMI) were calculated. RESULTS : The median (interquartile range) KDRI was 1.2 (0.9 - 1.6), confirming that low- to average-risk donors were being utilised. Similarly, the median UK KDRI was 0.9 (0.8 - 1.2). Both these scores performed poorly in predicting graft and patient survival, with a C-statistic of 0.5. Renal recipient risk scores also demonstrated low- to average-risk patients being transplanted, with a median Hennepin score of 2 - 4 points and a KTMI of 2 points. These recipient scores predict increased recipient mortality at high scores, albeit with low sensitivity, and were not significantly associated with graft survival. CONCLUSION : Deceased-donor and renal recipient risk scores commonly used internationally performed poorly in predicting graft survival in our cohort, and should be used with caution in the SA setting. A conservative approach to organ donor referral and utilisation as well as renal transplant recipient listing was noted.
Mental health update - update on depression with a focus on vortioxetine
(Medpharm Publications, 2024) Jordaan, Beatrice
Depression, identified by the World Health Organization (WHO) in the International Classification of Diseases (ICD-11) as a complicated andmultifaceted condition, affects around 280 million people globally. In sub-Saharan Africa, mental health disorders, including depression,account for nearly 10% of the total disease burden, with depressive disorders being the most frequently diagnosed. Symptoms of depressioncan range from feelings of worthlessness and difficulty concentrating to sleep disruptions and suicidal ideation. Among the different typesof depression, major depressive disorder is the most prevalent. Extensive research has explored potential mechanisms contributing todepression, including genetic, neurochemical, and hormonal influences, such as those involving the hypothalamic-pituitary-adrenal axis.While both pharmacological and non-pharmacological treatments can effectively manage depression, antidepressants are typically the firstchoice. Vortioxetine, an antidepressant with multimodal activity, stands out due to its unique mechanism of action, combining serotonintransporter inhibition with direct modulation of 5-HT receptors. When left untreated, depression can result in serious physical, emotional andbehavioural health concerns. This review seeks to summarise current theories on the origins of depression and treatment strategies, with afocus on the therapeutic potential of vortioxetine.
Director's statement
(Institute for Afro-Hellenic studies, 2024-12) Steyn, Raita
No abstract available
Newborn birth weight and its associated risk factors in Somalia using Somalia health and demographic survey
(Elsevier, 2025-03) Belay, Denekew Bitew; Birhan, Nigussie Adam; Ali, Mahad Ibrahim; Chen, Ding-Geng (Din)
Please read abstract in the article.
The slow pandemic : emergence of antimicrobial resistance in the postadvent of SARS-CoV-2 pandemic
(Wiley, 2025-04) Osunla, Ayodeji; Oloye, Femi; Kayode, Adeoye John; Femi-Oloye, Oluwabunmi; Okiti, Ayomide; Servos, Mark; Giesy, John
BACKGROUND : The unprecedented outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has dramatically changed the global approach to public health, emphasizing the importance of measures to control and prevent infections. In response to the COVID-19 crisis, stringent hygiene practices and surface disinfection have become the norm, with an unprecedented surge in the use of disinfectants and antiseptics (DAs). MAIN TEXT : While these measures have been crucial in curbing the spread of the virus, an emerging concern has taken center stage: the potential impact of the prolonged and widespread use of antimicrobial compounds in these products on the development of antibiotic resistance. Antimicrobial resistance (AMR) has long been recognized as one of the most pressing global health threats. Quaternary ammonium compounds (QAC) such as benzalkonium chloride, benzethonium chloride, and cetylpyridinium chloride, which are extensively used in DAs formulations, have gained less attention in the context of AMR. CONCLUSION : A high abundance of QACs was detected in wastewater, and certain bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterococcus species developed resistance to these compounds over time. We analyzed the available evidence from the scientific literature, examining the presence and concentrations of QACs in different water sources, and their resistance mechanisms. This review aimed to shed light on the multifaceted challenges that arise from the dual battle against the COVID-19 pandemic and the ongoing global fight against AMR.
Spatio-temporal dynamics of Isoberlinia-dominated woodlands in disturbance-prone landscapes over 15 years
(Elsevier, 2025-06) Idjigberou, Shegoun Eudes; Assede, Emeline Sessi Pelagie; Biaou, Severin; Gouwakinnou, Gerard Nounagnon; Natta, Armand Kuyema; Biaou, Samadori Sorotori Honore
Understanding the impact of productivity and disturbance on vegetation succession is a crucial debate in community ecology, with significant implications for biodiversity conservation. Productivity and disturbance influence species richness and structure, enhancing our understanding of vegetation dynamics and species coexistence over time. Numerous theories, such as the Intermediate Stress Hypothesis, Intermediate Disturbance Hypothesis, and Dynamic Equilibrium Model, have been proposed to explain these mechanisms. However, our understanding of how productivity and disturbance affect the spatio-temporal dynamics of Isoberlinia-dominated woodlands remains limited. We analyzed floristic data from sixteen sites with 64 permanent plots (400 m² each) along a south-north precipitation gradient (1112–991 mm per year) over 15 years (2006–2020). We calculated species richness and density for sapling and adult trees, and estimated two main variables: potential productivity using water deficit as a proxy, and disturbance intensity using logging rate. A linear mixed effects model, with plots nested within sites as random variables, was developed to test the effect of potential productivity and level of disturbance on species richness and density, for sapling and adult trees. Our results showed that species richness (SR) and density, for saplings and adult trees decreased over time, regardless of the disturbance and potential productivity gradients. Compared to higher levels of disturbance, low and medium levels of disturbance significantly increase the species richness of saplings and adult trees. In addition, the density of adult trees and saplings decreased over time, but increased with the level of disturbance from high to low. These results suggest that increased disturbance reduces the density of woodland species in favor of invasive species, typically savanna species. Overall, our results are consistent with the Dynamic Equilibrium Model, highlighting the complex interactions between disturbance regimes, productivity gradients, and their effects on species richness within ecosystems. Efficient forest management in Isoberlinia-dominated would avoid the high levels of logging that promote the establishment of invasive species and would maintain the biodiversity of this ecosystem in the long term. HIGHLIGHTS • Examined how the productivity and disturbance affect the spatio-temporal dynamics of Isoberlinia-dominated woodlands. • Analyzed data from 64 permanent plots along a south-north precipitation gradient over 15 years. • Species richness and density for saplings and adult trees decreased over time. • Low to medium disturbance levels increase the richness of saplings and adult trees compared to higher levels. • Increased disturbance favored invasive savannah species over woodland species.
Achieving the global biodiversity framework under climate change
(Wiley, 2025-05) Archer, Emma Rosa Mary; Arneth, Almut; Leadleay, Paul; Mori, Akira; Obura, David; Smith, Pete; emma.archer@up.ac.za
We have committed to ambitious targets under the Global Biodiversity Framework, but projected climate change makes the achievement of many of these targets extremely difficult and will effectively require a significant rethinking in how to achieve multiple targets. In this Opinion, we have chosen to focus on selected targets, considering how their achievement is likely to be compromised by climate change but also what the possibility of real response options might be. We focus on restoration (Target 2), spatial planning and integration (Targets 1, 2, 3 and 10), sustainable use and sustainable benefits to people (Targets 5, 9 and 10) and, finally, equity and social justice (Targets 13, 20–23 and Goal C). Now more than ever, the window for effective action on climate change and biodiversity is closing, requiring rapid and, most importantly, collective action.
A third biodiversity metric in the third pole
(Wiley, 2025-04) Oberlander, Kenneth Carl; kenneth.oberlander@up.ac.za
The readers of this journal need no introduction to the threat posed to biodiversity by anthropogenic factors such as habitat degradation and climate change. The (sometimes considerable) efforts by many national governments to increase biodiversity protection over the last few decades, via the establishment of protected areas for conservation, have nevertheless met with criticism, particularly with regard to the evidence base used for the establishment and expansion of such protected areas (Maxwell et al. 2020). This is particularly acute for regional planning efforts involving multiple governments, where the effects of national borders on biodiversity conservation may have profound consequences in the near future (Li et al. 2025). Ideally, such decisions should be made taking into account evidence from multiple different levels of biological organisation, but this is seldom achieved in reality.
The role of expert evidence in civil litigation : a critical analysis (Part 1)
(University of the Free State, 2023-07) Bekker, Petrus Thino
Section 34 of the Constitution of the Republic of South Africa provides that everyone has the right to have any dispute that can be resolved by the application of law decided in a fair public hearing before a court or, where appropriate, another independent and impartial tribunal or forum. A number of foundational principles that underlie the South African law of civil procedure had been afforded express recognition by this section. One of these principles entail that the duration and costs of civil litigation should be reasonable. In the past decade, or so, there have been several initiatives to give effect to this ideal of civil justice for all. Despite this, there are still several impediments in the South African law that causes civil trials too be exorbitant and time-consuming. One of these impediments relate to the presentation of expert evidence testimony. Part one of this article will critically discuss the historical development of Uniform Court Rule 36(9), its recent amendments and the critique raised against the procedure. In part two the position in relation to the presentation of expert witness evidence in England and Wales, and Australia, as well as its possible contribution to the South African law will be discussed. It will be argued that the current procedure relating to the presentation of expert evidence in South Africa still has certain shortcomings and that the Rules Board will have to intervene to ensure that the procedure enhances access to justice in civil matters.
The role of expert evidence in civil matters : a critical analysis (Part 2)
(University of the Free State, 2024-06) Bekker, Petrus Thino
In the first part of this article, the author analysed the development and role of expert evidence in civil matters in the South African law (Bekker 2023:160-178). In the second part of this article, the author conducts an in-depth discussion of the position in England, Wales, andAustralia in relation to the application of expert witness testimony in civil matters. It is argued that, although there has been considerable progress in terms of the presentation of expert evidence in civil litigation in the South African law, a number of problematic aspects still need to be addressed. It is recommended that the Rules Board should intervene and that the rules relating to the presentation of expert evidence in civil matters should be amended in its entirety. In this regard, valuable insight can be gained from the English and Australian experiences.
The presentation of witness testimony in civil matters-time for a new approach? (Part 1)
(University of Fort Hare, Nelson R Mandela School of Law, 2024-12) Bekker, Petrus Thino
The problems in relation to access to justice in civil matters are not unique to South Africa but are of global concern. After the adoption of the final Constitution in 1996, several initiatives have been implemented in South African law in an attempt to enhance access to justice in civil matters as guaranteed by section 34 of the Constitution. Some of these initiatives are related to the presentation of evidence at the trial of a civil action. More than twenty years ago, there were several unsuccessful pleas from academic writers advocating that a similar position to England and Wales should be considered in South African law in relation to the compulsory exchange of witness statements before trial. It therefore seems like an opportune time to revisit the development relating to the exchange of witness statements in South Africa over the past few decades. Moreover, it is important to not only embark on an analysis of the exchange of witness statements, but also to look at the presentation of all evidence during action trials, including affidavit evidence. Part 1 of this article provides a comparative study between the presentation of witness evidence at trial in South Africa, England and Wales. The discussion firstly focuses on the presentation of witness testimony in South Africa and the exceptions to the general rule that it should be presented orally in court. Secondly, the position in England and Wales will be critically evaluated, as well as the newest developments relating to the presentation of witness evidence during trial. In part 2 of this article, some of the developments concerning the presentation of witness evidence in trial actions in Australia are critically examined. Lastly, some possible alternatives to the current presentation of witness testimony in South Africa are considered.
An overview of antifogging nanocoatings : recent developments and application
(Elsevier, 2024-12) Sanni, Omotayo; Ren, Jianwei; Jen, Tien-Chien; jianwei.ren@up.ac.za
Transparent materials are essential to our daily lives. It's very well recognized that their use in windshields, cars, windows, mirrors, and eyewear makes our everyday tasks more comfortable. In addition to these, several other instances may be found in the culinary, medical, and solar industries, among other spheres of human endeavor. Unfortunately, under typical operating conditions, this material experiences fogging owing to the unavoidable condensation of water vapor on solid surface. Researchers are becoming more and more interested in antifogging nano-coatings with remarkable water repellence as a result of the growth of the coating industries and material engineering. Numerous compounds have been created by researchers thus far to prepare antifogging films. There have been reports on the mechanisms and guidelines for the creation of these agents by various technologies as a result of the core requirements of various fields. We present the latest developments in antifogging nanocoatings and antifogging performance test procedures in this review. Additionally, there has been a focus on offering understanding of the latest advancement in superhydrophobic coating through the application of nanotechnology. According to the literature, the reported antifogging films do not show sufficient results and continue to pose a practical issue that requires real-world application. As a result, antifogging techniques need to be improved further.
Nonlinearities in FDI allocations : why good institutions matter more with rising FDI locational concentrations
(Africa Growth Institute, 2024-12) Fedderke, Johannes W.; Luiz, John; Barnard, Helena
This paper extends an established finding: that institutions are important for foreign direct investment (FDI). Our results show that institutions are both more and less important than previous empirical results suggest. This is because the concentration of FDI in a location matters. Theoretically, if institutions serve a risk-mitigating role, then rising locational concentration of FDI compromises the risk diversification function that multiple locations for FDI provides. This can be offset by high-quality institutions. The implication is that the impact of institutions on FDI will be enhanced with rising FDI concentration. Empirically, we examine the locations of outward FDI from South Africa from 1996-2019, confirming the presence of a strong association between FDI and an institutions-FDI concentration interaction term. The result is robust to many alternative means of measuring institutions and to a number of alternative means of representing the implied nonlinearity in estimation. The inference is that for any location that is intent on attracting strong concentrations of FDI inflows, the general precept that sound institutions are important in attracting FDI flows is enhanced, both in terms of the strength of institutional improvement, and the breadth of institutions that require attention.
The effects of critical mineral endowments on green economic growth in Latin America
(Elsevier, 2024-11) Hwang, Young Kyu; Diez, Angeles Sanchez; Inglesi-Lotz, Roula
In the context of global low-carbon energy transition for addressing the climate crisis and global warming, soaring demand for critical minerals—essential inputs for most clean energy technologies—is expected in the coming decades. However, extracting critical minerals from the mine might have significant negative impacts on environmental sustainability and the socioeconomic well-being of the citizens where such activities take place. The paramount importance of critical minerals for global net-zero goals and their controversy on sustainable development goals motivated us to investigate the effects of critical minerals on green growth in 10 mineral-rich Latin American countries from 2000 to 2020. Firstly, the effect of critical minerals on green growth is analyzed in both disaggregated and aggregated terms. Subsequently, the moderation effect of institutional quality is examined on the nexus between critical minerals and green growth. After which, the non-linear effect of critical minerals on green growth is analyzed, conditioned on the values of five threshold variables using panel fixed-effect threshold regression. Lastly, the primary channels by which critical minerals affect green growth are identified using panel mediation analysis. The findings of this study are highlighted as follows: In aggregate terms, critical mineral contributes to increasing green growth, but its effect depends largely on the type of each critical mineral. When combined with critical minerals, the moderation effect of institutions on green economic growth is ambiguous. The effect of critical minerals varies significantly and shows non-linearity depending on the values of each threshold variable. Critical minerals influence green growth through five channels: exchange rate, renewable energy share in electricity capacity, fossil fuel dependency, government debt, and economic complexity.

Browse

Recent Submissions