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Schottky diodes based on polyaniline-graphene nanocomposites : tuning barrier characteristics through swift heavy ion irradiation
Chilukusha, Daniel C.; Mboukam, Jean J.; Maphiri, Vusani M.; Manyala, Ncholu I.; Msimanga, Mandla (Elsevier, 2026-04-01)
Current chemical and electrochemical methods lack the nanoscale control required to optimize polymer–metal interfaces for electronic applications. In this work, swift heavy ion (SHI) irradiation is employed to tune the barrier characteristics of Schottky diodes based on polyaniline–graphene nanocomposites (PANI-G NCs) and aluminum. Current density–voltage (J–V) measurements confirmed rectifying behavior in all devices. Key parameters including ideality factor (n), barrier height (Φb), and rectification ratio (γ) were extracted from semi-logarithmic J–V plots. The unirradiated PANI device showed the lowest n (3.8) and the highest γ (98.6). Incorporation of graphene and SHI exposure led to decreased γ and Φb, and increased n, attributed to interfacial inhomogeneities and oxide formation. Differential resistance (dV/dI vs. V) analysis revealed a decline in shunt resistance with fluence, making series resistance (Rs) dominant in charge transport. Cheung’s and Norde’s methods further showed that Rs decreased with fluence, indicating enhanced charge injection. The energy distribution of interface states shifted exponentially toward the valence band edge with increasing bias and dose. At higher voltages, irradiated devices transitioned from trap-limited to trap-free space-charge-limited conduction, suggesting SHI exposure promotes carrier detrapping. These results highlight the tunability of PANI-G SBDs via SHI irradiation and their potential for applications such as Schottky-type photodetectors and low-power rectifying elements in flexible optoelectronic systems. HIGHLIGHTS • Swift heavy ion (SHI) irradiation tunes Schottky diode properties in PANI-graphene nano composites. • SHI exposure reduces rectification ratio and barrier height, and increases ideality factor. • SHI lowers shunt resistance, enhances charge injection via reduced series resistance. • Irradiated devices transition from trap-limited to trap-free conduction at higher voltages. • Work demonstrates SHI-tailored PANI-G diodes for next-generation flexible optoelectronics
Exposure to second-hand smoke, tobacco advertising, and school curriculum on tobacco harms in South African adolescents : findings from the Global Youth Tobacco Survey
Londani, Mukhethwa; Sewani-Rusike, Constance; Ayo-Yusuf, Olalekan Abdulwahab; Oladimeji, Olanrewaju (BioMed Central, 2026-01)
BACKGROUND : Comprehensive smoke-free policies are necessary to protect South African adolescents against second-hand smoke exposure. This study aims to estimate the prevalence of second-hand smoke and identify factors associated with exposure to second-hand smoke among adolescents. This study also assesses factors responsible for adolescents’ female-male gap in exposure to second-hand smoke. METHODS : Global Youth Tobacco Survey (GYTS) data was used to estimate the second-hand smoke prevalence. Participants comprised 6287 never-smoking adolescents. Chi-Square tests and modified Poisson regression analyses were conducted to identify factors associated with adolescents’ second-hand smoke exposure. Fairlie’s decomposition technique was applied to understand the relative contribution of different covariates to the female-male gap in second-hand smoke. RESULTS : Overall, 39.7% of all never-smoking South African adolescents reported exposure to second-hand smoke at home and/or in places other than home. By specific location, the prevalence of second-hand smoke exposure at home and in places other than home was 22.2% and 32.8%, respectively. Second-hand smoke was related to age, grade, and smoking parents or guardians, according to modified Poisson regression models. The data also suggest that the proportion predicting second-hand smoke exposure is 44.56% for females and 37.85% for males, resulting in a 6.71% gender gap. Tobacco advertisement was the most significant contributor to the gender disparity in second-hand smoke exposure. CONCLUSION : Second-hand smoke exposure is still prevalent among South African adolescents. This necessitates a full discussion of strategies aimed at reducing second-hand smoke exposure. Effective smoke-free policies for the home and public areas should be devised and properly enforced.
Remote sensing for forage ratio estimation : a systematic review
Rapiya, Monde; Ngcoliso, Nasiphi; Truter, Wayne; Ramoelo, Abel (Taylor and Francis, 2026)
Remote sensing has emerged as a vital technology for monitoring vegetation dynamics and ecosystem health, particularly in assessing forage quality and quantity. This study investigates the application of remote sensing tools for forage ratio estimation. A bibliometric analysis was conducted in RStudio (v4.0.4), biblioshiny using datasets obtained from the Dimensions, Scopus and Web of Science (WoS) databases, covering the period from 2005 to 02/2025 and guided by the PRISMA approach. The analysis indicates a generally low but steadily increasing research output, with notable peaks observed in 2014, 2020 and 2023. Notably, significant progress in remote sensing technologies particularly hyperspectral and multispectral imagery has enhanced the capacity to accurately estimate key forage quality parameters, including Carbon:Nitrogen (C:N) and Nitrogen:Phosphorus (N:P) ratios. Machine learning algorithms, especially random forest models, have proven effective in improving predictive accuracy for forage quality assessments. Despite these technological strides, research remains concentrated in the Northern Hemisphere, with limited contributions from developing nations, particularly in the Southern Hemisphere, highlighting a critical geographic disparity. Our keyword analysis further underscores a growing trend towards integrating machine learning with remote sensing to monitor forage ecosystems. This review calls for enhanced international collaboration and investment in underrepresented regions, emphasizing the necessity for equitable access to remote sensing technologies. As ecological challenges intensify, the continued exploration of remote sensing methodologies for forage ratio assessment is crucial for promoting sustainable land management practices and wildlife conservation efforts. Future research should focus on refining predictive models and expanding applications across diverse ecosystems, thereby maximizing the potential of remote sensing in effective forage ecosystem management.
Digital co-creation of public safety knowledge in Cape Town : multi-stakeholders and civil society-led empowerment
Mangai, Mary S.; Wilhelm, Jan Lorenz; Ayodele, Austin A. (Emerald, 2026)
PURPOSE : This study investigates how civil society and multi-stakeholder networks in Cape Town leverage digital tools to co-create public safety knowledge and improve crime-prevention practices. It aims to uncover the mechanisms through which civil society actors, community organisations, neighbourhood watches, private security firms, policing forums and residents collectively deploy digital platforms to enhance information sharing and mutual learning. DESIGN/METHODOLOGY/APPROACH : We conducted 26 in-depth interviews in 2023 with representatives of diverse stakeholder groups active in Cape Town's public safety ecosystem. Interview transcripts were analysed using Atlas.ti for inductive content analysis. Open and axial coding allows us to identify emergent themes around self-organised digital solutions and evolving regulatory frameworks. FINDINGS : Grassroots civil society actors drive a digital shift by adopting low-barrier technologies, such as collaborative messaging apps and shared camera-control rooms, that break down silos and accelerate the sharing of real-time insights. Multi-stakeholders report enhanced responsiveness and coordination. Simultaneously, policymakers have introduced updated data protection rules, drone licensing requirements and clarified intellectual property regulations to strike a balance between innovation, privacy, legality and accountability. RESEARCH LIMITATIONS/IMPLICATIONS : The study's single-city focus and reliance on experts' interview data may limit generalisability. Future research should incorporate comparative case studies across multiple urban contexts and integrate quantitative measures of safety outcomes to validate and extend these findings. PRACTICAL IMPLICATIONS : Our findings offer actionable guidance for municipal authorities, regulators and civil society organisations on designing inclusive, human-centred digital frameworks. Prioritising low-barrier technologies and establishing clear, flexible regulatory pathways can enhance multi-stakeholder collaboration and accelerate operational effectiveness in crime prevention. SOCIAL IMPLICATIONS : Digitally empowered networks function as “social glue,” fostering community cohesion and empowering marginalised groups to participate in public safety governance. By breaking down traditional barriers to information sharing, these digital collaborations strengthen social resilience during periods of crisis and chronic insecurity. ORIGINALITY/VALUE : This is one of the few in-depth qualitative studies to examine civil society–led digital co-creation of public safety knowledge in Cape Town. It uniquely integrates perspectives on grassroots empowerment, technology adoption and regulatory oversight, providing novel insights for scholars and practitioners seeking to harness civil society's agility in crisis governance.
Pathological findings in 61 free-ranging leopards (Panthera pardus) from the Greater Kruger National Park, South Africa. Part Two : non-parasitic conditions
Mitchell, Emily P.; De Klerk-Lorist, Lin-Mari; Buss, Peter; Reininghaus, Bjorn; Bengis, Roy (Elsevier, 2026-07)
Few reports on diseases in free-ranging leopards (Panthera pardus) are available. A retrospective review of tissues from free-ranging leopards from the Greater Kruger National Park, South Africa, that were submitted for histological examination was conducted. Non-parasitic lesions were recorded in 61 free-ranging juvenile to elderly leopards. They had died or been euthanized between 1998 and 2023. Parasitic conditions in these leopards have been reported separately. Traumatic injury was common (41%). Respiratory tract conditions included pneumoconiosis (36%) and tuberculosis (23%), presumed to be due to Mycobacterium bovis infection in this endemic area. Classic granulomata were not present in the paucibacillary histiocytic lung lesions. Coronary arteriosclerosis, present in 36% of leopards, may be age-related, together with glomerulopathy (26%), adrenal gland corticomedullary fibrosis (8%), thyroid gland epithelial lipofuscinosis (n = 3), inactive ovaries (n = 2), obsolescent glomeruli (n = 1), pancreatic nodular hyperplasia (n = 1), bile duct carcinoma (n = 1) and cutaneous fibroma (n = 1). Mild tissue inflammation including interstitial nephritis (34%) and periportal hepatitis (28%) was often recorded. Tuberculosis and rabies were the only diagnosed infectious diseases recorded in this series of leopards, 85% of which were euthanized due mainly to the perceived risk they posed to humans rather than clinical illness. Apart from these diseases and trauma, most of the lesions noted in these animals were likely incidental in free-ranging animals. Lack of information on population dynamics and disease status in the free-ranging leopard population means that the true prevalence of these conditions is not known.