Ibrahim Badamasi Babangida University

Background Adult hepatitis B virus (HBV) vaccination remains a critical yet underutilized component of viral hepatitis prevention in many high-endemic settings. Although infant HBV vaccination has been widely integrated into national immunization programmes, adult vaccination often depends on individual awareness, healthcare access, and provider recommendation. Community-based evidence on the determinants of adult HBV vaccine uptake is needed to inform adult immunization strategies in resource-constrained settings. Objective To examine the individual- and health-system level factors associated with adult HBV vaccine uptake in a community-based population in a high-endemic setting and identify priorities for strengthening adult vaccination programmes. Methods We conducted a community-based cross-sectional survey among adults in Minna, Nigeria, using multistage sampling. Data on sociodemographic characteristics, HBV-related knowledge, healthcare access, and vaccination status were collected using interviewer-administered questionnaires. Modified Poisson regression with robust variance estimation was used to identify factors independently associated with vaccine uptake, with adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) reported. Results Among 426 participants, 167 (39.2%) had received at least one dose of HBV vaccine, and 38.5% had completed the vaccination series. In bivariate analyses, vaccine uptake was significantly associated with education, occupation, residence type, ward, religion, HBV knowledge, and health worker recommendation (all p < 0.05), whereas gender and marital status were not associated. In multivariable analysis, moderate knowledge (aPR 14.82; 95% CI 4.37–50.30), high knowledge (aPR 14.49; 95% CI 4.25–49.40), and health worker recommendation (aPR 3.37; 95% CI 1.90–5.98) were independently associated with vaccine uptake. Conclusions Adult HBV vaccination coverage remained suboptimal in this community-based population. Vaccine uptake was independently associated with modifiable individual- and health system-level factors, particularly HBV knowledge and healthcare worker recommendation, highlighting opportunities to strengthen provider-initiated vaccination, improve community awareness, and expand access to adult vaccination services. These findings provide community-based evidence to support the design and prioritization of adult immunization programmes in high-endemic settings. Owing to the cross-sectional design, the observed associations should not be interpreted as causal.

Retirement anxiety has emerged as a significant psychosocial concern among teachers, particularly in developing countries where uncertainties surrounding pension administration, financial security, healthcare, and post-retirement adjustment often undermine overall well-being. Despite growing scholarly interest in retirement preparedness, empirical evidence on the relationship between retirement anxiety and teachers' physical and cognitive well-being remains limited in the Nigerian context. This study examined the relationship between retirement anxiety and the physical and cognitive well-being of senior secondary school teachers in Niger State, Nigeria. A correlational research design was employed. The study population comprised senior secondary school teachers in Niger State, from which a sample of 335 respondents was selected using appropriate sampling procedures. Data were collected using validated structured questionnaires, while Pearson Product Moment Correlation (PPMC) was used to test the hypotheses at the 0.05 level of significance. The findings revealed a statistically significant positive relationship between retirement anxiety and physical well-being (r = 0.702, p < .05), as well as between retirement anxiety and cognitive well-being (r = 0.714, p < .05). These findings suggest that retirement anxiety is significantly associated with teachers' well-being, underscoring the importance of addressing retirement-related concerns before the transition from active service. The study concludes that strengthening retirement preparedness through comprehensive pre-retirement counselling, financial literacy education, psychosocial support, and health promotion programs is essential for enhancing teachers' well-being and facilitating a smoother transition into retirement. The findings contribute to the growing discourse on teacher welfare and provide evidence to inform educational policy and retirement planning interventions in Nigeria and other developing contexts.

The Boko Haram conflict continues to education through school closures, destruction of educational infrastructure, and displacement of teachers and learners. This study examined the effect of Boko Haram insurgency on educational development and literacy rate in Borno North Senatorial District of Borno State, Nigeria. The study was anchored on Social Disorganisation Theory, which explains how prolonged insecurity weakens community institutions, social cohesion, and the capacity to provide essential services such as education. A descriptive crosssectional survey design was adopted. A sample size of 499 respondents was drawn and respondents were stratified by LGA, gender, and role as teachers, learners, and community leaders. Resprondents were selected using multi-stage sampling technique. Data were collected using structured questionnaire and analysed using Partial Least Squares Structural Equation Modelling. The measurement model demonstrated adequate reliability and convergent validity, with composite reliability values ranging from 0.826 to 0.834 and average variance extracted values ranging from 0.532 to 0.582. The structural model revealed that Boko Haram insurgency has a strong and statistically significant negative effect on educational development and literacy rate, measured in terms of school enrollment, completion, and literacy scores (β = -0.733, T = 23.092, p = 0.000). The model further showed that Boko Haram insurgency explained 53.7% of the variance in educational development and literacy rate. The study concludes that persistent Boko Haram insurgency significantly undermines educational development and literacy in Borno North Senatorial District. The study recommends strengthened school security and community-based protection, rehabilitation of damaged schools, and educational recovery programmes, among others.

Perovskite solar cells (PSCs) have made significant advances in power conversion efficiency (PCE); however, their commercial viability remains hindered by stability concerns with organic transport layers and the environmental toxicity of lead-based absorbers. This study investigates a lead-free germanium-based perovskite solar cell (CH3NH3GeI3) with inorganic charge transport layers of zinc oxide ZnO and copper iodide CuI as electrons and holes transport layers, respectively, using SCAPS-1D simulation. The device design consists of FTO/ZnO/ CH3NH3GeI3/CuI/Au in a standard n-i-p configuration. Key parameters were extensively optimized, including absorber layer thickness (300-800 nm), absorber layer bandgap (1.2-1.6 eV), ZnO electron transport layer (ETL) thickness (10-400 nm), and ZnO bandgap (2.0-4.0 eV). The results show that an optimal absorber thickness of 500-600 nm and an optimal bandgap of 1.4-1.5 eV produce a maximum PCE of about 24.9%. While differences in ZnO thickness have little effect on open-circuit voltage (Voc) and fill factor (FF), parasitic absorption causes small reductions in short-circuit current density (Jsc) and PCE. Increasing the ZnO bandgap improves device transparency while modestly improving performance. Temperature analysis (290-360 K) shows a considerable decrease in Voc, FF and PCE as temperature increase, whereas Jsc remains almost constant, indicating recombination dominated thermal degradation in Ge-based PSCs. Overall, this study demonstrates that optimizing inorganic transport layers and absorber layer can significantly increase the efficiency and stability of lead-free PSCs, providing valuable insights for creating environmentally friendly and thermally robust solar systems.

Fractional reaction–diffusion models provide a powerful framework for describing dynamical systems in which memory effects and spatial interactions are significant. In this study, we develop and analyze a spatially heterogeneous time-fractional reaction–diffusion model for the coupled dynamics of cocaine and heroin abuse. Memory effects associated with addiction persistence, delayed behavioral responses, and relapse are incorporated via Caputo time-fractional derivatives, whereas spatial heterogeneity is represented by space-dependent diffusion coefficients, including both smoothly varying diffusion profiles and multi-patch configurations that capture regional disparities. To efficiently approximate the resulting nonlinear fractional system, we propose a fractional extension of the Parker–Sochacki method for time-fractional reaction–diffusion equations with heterogeneous diffusion. The proposed scheme provides an explicit and computationally efficient numerical algorithm that significantly reduces the substantial memory requirements typically associated with fractional-order models. The mathematical properties of the model are investigated rigorously. The existence, uniqueness, positivity, and boundedness of solutions are established using the theory of sectorial operators, and the equilibrium states are characterized. Furthermore, global stability conditions are derived using appropriate Lyapunov functionals. Numerical simulations validate the proposed approach and demonstrate the combined effects of memory and spatial heterogeneity on cocaine–heroin dynamics. In particular, lower fractional orders are shown to promote prolonged persistence of substance abuse, while heterogeneous diffusion generates pronounced nonuniform spatial distributions. The proposed framework integrates methodological advances with epidemiological insight, offering a robust tool for studying substance-use dynamics in spatially heterogeneous environments.