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Hierarchical forecasting of COVID-19 cases in Africa using machine learning models
(Frontiers in Epidemiology, 2026) Shoko, Claris; Makatjane, Katleho; Sigauke, Caston
Introduction: The COVID-19 pandemic posed significant challenges for public health systems, especially in Africa, where data scarcity, inadequate healthcare infrastructure, and regional disparities hindered effective forecasting and response efforts. Conventional forecasting methods have faced challenges in adequately addressing the complexity and detail necessary for effective policy interventions at various administrative levels. This study examines the challenge of producing accurate and coherent forecasts of COVID-19 cases within the hierarchical structure of Africa, which includes the continental, regional, and national levels. Methods: To establish a comprehensive forecasting model that uses hierarchical time series forecasting through a bottom-up reconciliation approach augmented by machine learning algorithms. We employ extreme gradient boosting (XGBoost) and random forest models, subsequently improving predictive accuracy via a weighted average ensemble method. We produce forecasts at the national level and then aggregate them to ensure consistency across all hierarchical levels. The models are evaluated in comparison to conventional methods such as ARIMA and exponential smoothing. Results: Empirical findings indicate that XGBoost is the best among all the single forecast models used in this study, combining forecasts from the XGBoost with the random forest and assigning more weights to the XGBoost surpasses all other models in the area of mean absolute error, root mean square error, and mean absolute scale error. Results further revealed that Southern Africa, despite its low population density, reported the highest number of cases, indicating underlying health vulnerabilities and socioeconomic factors. In summary, the bottom-up HTSF method, when combined with machine learning, serves as an effective tool for forecasting in environments with limited data availability. Discussion: It is advisable to apply similar models to other infectious diseases and to expand their use to guide health interventions, resource allocation, and early warning systems in future pandemics.
Peptide-functionalized gold nanoparticles lowered diet-induced obesity in rats by reducing white adipose tissue mass
(Institute of Physics, 2026) Modise, Keletso; Sibuyi, Nicole Remaliah Samantha; Madiehe, Madimabe Abram; Meyer, Mervin; Meyer, Samantha; Fadaka, Adewale Oluwaseun; Gabuza, Kwazi B
Anti-obesity drugs are limited in their application due to poor drug specificity, efficacy, and bystander side effects. The study reports on the use of bi-functionalized gold nanoparticles (AuNPs) to improve the selectivity and efficacy of therapeutic agents in obese male Wistar rats. Citrate-capped AuNPs (cAuNPs) were functionalized with Adipose Homing Peptide (AHP) and with or without a D(KLAKLAK)2 peptide (KLA); i.e., AuNP-AHP-KLA and AuNP-AHP, respectively. The rats were grouped into lean (low fat, LF), obesity-resistant (high fat, HF1), and three groups (HF2, HF3 and HF4) from obesity-prone rats. Rats were intravenously injected every third day for four weeks with their respective treatments; phosphate buffered saline (LF and HF2), AuNP-AHP-KLA (HF1 and HF4), and AuNP-AHP (HF3). Urinalysis was performed during the first and the fourth week of treatments. Oral Glucose Tolerance Test (OGTT) was performed after the third week of treatment. AuNPs distribution in white adipose tissues (WATs) and the liver of rats on HF1, HF3 and HF4 groups was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Treatment with AuNP-AHP-KLA (HF4) reduced the body weight and adipose tissue mass of the obese rats in HF4, and improved their glucose tolerance. Urinalysis showed that the AuNPs conjugates did not cause any toxicity to the rats after four weeks of treatment. High content of gold (Au) was detected in the WATs of HF3 group treated with AuNP-AHP, and negligible amount of Au was found in the HF1 and HF4 groups treated with AuNP-AHP-KLA. The preliminary data confirmed that bifunctionalized-AuNPs can potentially be effective theranostic tools for obesity treatment. Further studies are underway to determine the histological and molecular effects of this targeted nanotherapy.
Phase evolution of electrodeposited manganese oxide for supercapacitor applications
(Springer Science and Business Media Deutschland GmbH, 2025) Iwuoha, Emmanuel Iheanyichukwu; Nwanya, Assumpta Chinwe; Iheme, Chidozie W.
Energy is of paramount importance in our everyday lives and energy storage technologies are needed to solve the global energy problems largely. In this work, manganese oxide (MnxOy) films were electrodeposited chronoamperometrically on stainless steel (ss) and fluorine doped tin oxide (FTO) substrates at different step potentials. The effect of the deposition potential and temperature treatment on the phase and supercapacitive properties of the MnxOy were studied. At a step potential of less than 1.2 V no deposition was achieved while at 1.2 V, the as deposited oxide showed a bit of amorphousness with vestiges of Mn(OH)2 as evident from the x-ray diffraction (XRD) studies. At higher potentials (1.4 and 1.6 V), the as-deposited oxide appeared as the MnO2 phase. However, higher temperature treatment (600 °C) of all the deposits obtained at the various potentials resulted to Mn2O3 phase. The scanning electron microscopy (SEM) of the films showed that the as-deposited and the 400 °C annealed electrodes are porous while they become more compact and cemented at 600 °C. The obtained bandgap energies ranged from 1.26–2.65 eV for the films deposited at differing potentials and heat treatments. The electrochemical analysis shows the highest specific capacitance of 455 F g−1 for the 1.2 V@400 °C electrode while the Mn2O3 electrodes are more stable. The electrodes exhibited good potentials for supercapacitor application. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Olefin selectivity of K-Mn promoters on CoFe-ZSM-5 based catalyst in CO2 hydrogenation
(Frontiers Media SA, 2025) Mdleleni, Masikana Millan; Maseko, Paula; Cele, Mduduzi N.
The conversion of carbon dioxide (CO2), a major greenhouse gas, into light olefins is crucial for mitigating environmental impacts and utilizing non-petroleum-based feedstocks. Thermo-catalytic CO2 transformation into valuable chemicals offers a promising solution to this challenge. This study investigates the effect of potassium (K) and manganese (Mn) promoters on CO2 conversion and C2H4 selectivity over CoFe-ZSM-5 zeolites. Structural characterization via FTIR, pyridine-FTIR, and PXRD confirmed the successful incorporation of K and Mn into CoFe-ZSM-5 at 80°C without significant structural changes to the zeolite framework. BET analysis revealed that metal incorporation did not substantially alter the surface area, while SEM and TEM analyses confirmed the preservation of ZSM-5 spherical morphology. Fixed-bed reactor experiments conducted at 350°C and 20 bar demonstrated that K and Mn synergistically enhanced CO2 conversion efficiency and selectivity toward C2H4. The K-Mn/4Fe4Co-ZSM-5 catalyst (modified with 4% Co and 4% Fe) exhibited the highest performance, achieving 97% olefin selectivity. Furthermore, Mn and K promoters reduce the CO selectivity on the Co-Fe-ZSM-5 catalyst. These findings underscore the critical role of K and Mn in facilitating efficient CO2 activation and directing the reaction pathway toward valuable olefin products. Copyright © 2025 Maseko, Cele and Mdleleni.
Social safety and social security: validating context-specific instruments for Slums
(Springer Science and Business Media BV, 2026) Ako Abang, Zacheous; Romero, Liss D; Palacio, Katherine
Social safety and social security are concepts that help explain a community's well-being by assessing how it manages and mitigate existing, or perceived, risks. However, these terms are often conflated, which can limit understanding, particularly in areas with unstable living conditions. This study explores both concepts in the context of residents living in slums. As the number of displaced people grows, slums and informal settlements are becoming increasingly common worldwide, making it essential to clarify these concepts. Residents of slums face numerous hazards, including crime, violence, inadequate housing, overcrowding, and limited access to essential services. To measure social safety and social security, we developed two survey instruments. These were administered in Khayelitsha Site C, a post-apartheid township in Cape Town that includes both formal and informal settlements. We analyzed data from 514 participants using exploratory and confirmatory factor analyses, which confirmed the multidimensional nature of both concepts. The social safety instrument was refined to include ten items focused on perceptions of environmental risk, crime, and infrastructure, achieving a reliability score of (Ω = 0.90). The social security instrument, refined to eleven items, addresses environmental prevention, community leadership support, crime prevention, and health protection, with a reliability score of (Ω = 0.80). Both instruments demonstrated strong statistical validity through internal consistency, as well as evidence of convergent and discriminant validity. This research provides new, reliable tools for examining the challenges of social safety and social security in slums, offering actionable insights for policymakers and community development efforts.