University of Johannesburg
  • Johannesburg, Gauteng, South Africa
Recent publications
Susceptibility to foodborne disease is the inability of the host to prevent or overcome adverse effects caused by pathogens transmitted by food. This is increased by conditions that alter the host's defenses and modify the function of the immune system. Such factors are age (neonates, infants, young children, and the elderly because of a progressive immunosenescence), pregnancy (immune tolerance to the fetus), nutritional status, underlying health conditions (e.g., AIDS, cancer), and immunosuppressive therapies (especially after organ transplantation) can be responsible for this. This article describes some of these groups, the main foodborne agents involved and the basis for the vulnerability.
Project failure linked to poor performance of construction firms has highlighted the effectiveness of the tendering process in selecting capable contractors. Therefore, tender decisions are key to the success of a project from the conception to the completion of the project. The disconnect between decisions made during tendering and the execution of the project also is further challenging to the success of the project and overall productivity of the constructions sector. It is vital that the teams are aligned, as this will lead to project success and ultimately, organizational success. This research paper focuses on literature and research interviews conducted within South African construction organizations to establish the gap or cause of the disconnect between the two teams. The analysed research interviews present findings that indicate the results of the disconnect which are due to a lack of systems or procedures and siloed processes and structures within the organizations interviewed. The researcher recommends that further investigations need to be carried out to develop a solution that would standardize, systemize, integrate, and cross-skill the handover process between the estimators and project teams.
Agro-allied supply chain management (ASCM) presents unique issues ranging from dependence on climate, the engagement of many actors, to the bulk of the personnel’s lack of literacy, all of which need the use of communication and information technologies (IT). The purpose of the research is to present technologies centered on the Internet of things (IoT) and describe their applicability within the agro-allied industrial supply chain of a developing nation like Nigeria. The study recognized IoT-developed technologies in the framework of ASCM based on literature. In line with the study findings, the application of IoT in the food and agro-allied sector in Nigeria may help boost the growth of the agro-allied supply chain through significant reduction of waste as well as serving users’ needs in a long-term manner. In a developing country like Nigeria, IoT-based technology can integrate multiple ASCM tasks in an industrial setting.
The outbreak of COVID-19 has adversely affected university students’ learning process, especially in developing countries like Nigeria. Consequently, many institutions have adopted social media for the learning process because of the COVID-19 lockdown. Hence, the current study aimed at assessing the influences of social media learning environments on the learning process among university Architecture, Engineering, and Construction (AEC) students during the COVID-19 Pandemic lockdown. Data was collected from the students of AEC-related courses using a structured questionnaire. Warp 7.0 PLS-SEM was used for the analysis of the collated data and model development. The study results indicated that the AEC students’ psychological capital (PsyCap) moderates the relationships between social media learning environments and the learning process among AEC university students in Nigeria. The results also showed significant influence change between the social media learning environments and the learning process among the AEC students in Nigeria. The study is limited to students in the AEC-related courses in Nigerian universities. Moreover, the results of this study could be helpful to other developing countries having issues with the use of social media learning environments. The study further recommends the training of AEC students on the use of resources in the social media learning environments for the positive developmental state of the student’s self-efficacy, hope, optimism, and resilience.
Highlights Ti 3 C 2 T x MXene-based coaxial zinc-ion hybrid fiber supercapacitors (FSCs) were fabricated with braided structure, which can be prepared continuously and present excellent flexibility and ultrastability. A sports watch driven by the watch belts which weaved uses the obtained zinc-ion hybrid FSC and LED arrays lighted by the FSCs under embedding into textiles, demonstrating the great potential application in smart wearable textiles. Abstract Zinc-ion hybrid fiber supercapacitors (FSCs) are promising energy storages for wearable electronics owing to their high energy density, good flexibility, and weavability. However, it is still a critical challenge to optimize the structure of the designed FSC to improve energy density and realize the continuous fabrication of super-long FSCs. Herein, we propose a braided coaxial zinc-ion hybrid FSC with several meters of Ti 3 C 2 T x MXene cathode as core electrodes, and shell zinc fiber anode was braided on the surface of the Ti 3 C 2 T x MXene fibers across the solid electrolytes. According to the simulated results using ANSYS Maxwell software, the braided structures revealed a higher capacitance compared to the spring-like structures. The resulting FSCs exhibited a high areal capacitance of 214 mF cm –2 , the energy density of 42.8 μWh cm ⁻² at 5 mV s ⁻¹ , and excellent cycling stability with 83.58% capacity retention after 5000 cycles. The coaxial FSC was tied several kinds of knots, proving a shape-controllable fiber energy storage. Furthermore, the knitted FSC showed superior stability and weavability, which can be woven into watch belts or embedded into textiles to power smart watches and LED arrays for a few days.
Neonicotinoid insecticides have raised a lot of societal concerns due to their environmental ubiquity and unique mode of action. Therefore, it is of great research interest to monitor their occurrence in the environmental waters. However, these compounds exist at low concentrations that is below instrument detection limits. This study reports the applicability of magnetic poly (3 aminobenzoic acid)-based activated carbon (Fe 3 O 4 @PABA/AC) composite as an adsorbent in dispersive magnetic solid-phase microextraction ( d -MSPME) of neonicotinoid insecticides from wastewater and river water samples. The as-synthesized adsorbent was characterized and confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller and X-ray diffraction spectroscopy. The analytes of interest were detected and quantified by high-performance liquid chromatography coupled with diode array detector (HPLC–DAD). The parameters affecting the extraction and preconcentration processes, such as pH, extraction time, mass of adsorbent, desorption time and eluent volume, were optimized using fractional factorial design and central composite design. Under optimum conditions, the limits of detection and quantification were in the ranges of 0.41–0.82 µg L ⁻¹ and 1.4–2.7 µg L ⁻¹ , respectively. The linearity ranged from 1.4–700 µg L ⁻¹ with correlation of determination ( R ² ) values varied between 0.9933 and 0.9987. The intra-day and inter-day precisions were 0.35–0.75% and 1.7–5.5%, respectively. The spike recovery experiments were conducted to evaluate the accuracy of the d -MSPME analytical method in real samples, and the percentage recoveries ranged from 86.7 to 99.2%. Therefore, this method shows great potential applicability in preconcentrating the pollutants from the environment.
The accurate simulation of additional interactions at the ATLAS experiment for the analysis of proton–proton collisions delivered by the Large Hadron Collider presents a significant challenge to the computing resources. During the LHC Run 2 (2015–2018), there were up to 70 inelastic interactions per bunch crossing, which need to be accounted for in Monte Carlo (MC) production. In this document, a new method to account for these additional interactions in the simulation chain is described. Instead of sampling the inelastic interactions and adding their energy deposits to a hard-scatter interaction one-by-one, the inelastic interactions are presampled, independent of the hard scatter, and stored as combined events. Consequently, for each hard-scatter interaction, only one such presampled event needs to be added as part of the simulation chain. For the Run 2 simulation chain, with an average of 35 interactions per bunch crossing, this new method provides a substantial reduction in MC production CPU needs of around 20%, while reproducing the properties of the reconstructed quantities relevant for physics analyses with good accuracy.
Digital self-harm (DSH) is a relatively new form of virtual self-harm that occurs mostly in young people, and has been defined as both the act of cyberbullying oneself (Fictitious Online Victimisation; FOV), and engaging with online spaces in a way that is detrimental to one’s psychological wellbeing. In our overview of DSH we aim to provide an understanding of this little-known subject by offering a clarification of extant terms, summarising current findings, and presenting recommendations for future research. The prevalence of DSH in teenagers appears to approach that of physical self-harm, and the behaviour is more common amongst young people who are ostracised and/or victimised by their peers. The motivations for DSH are heterogeneous, but there is evidence that, like physical self-harm, it may be a means of affect regulation. However, more research is required to untangle the different forms of DSH and gain a sense of their occurrence in different populations and age groups, their varying causes, their relationship to physical self-harm, and the means by which they should be measured.
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16,664 members
Sathish Sundar
  • Faculty of Health Sciences
Joel Hinaunye Eita
  • Department of Economics and Econometrics
Shahed Nalla
  • Department of Human Anatomy and Physiology
Annemarie Avenant-Oldewage
  • Department of Zoology
Michael Hamblin
  • Laser Research Center
Information
Address
Auckland Park , 2006, Johannesburg, Gauteng, South Africa
Head of institution
Prof. Tshilidzi Marwala
Website
www.uj.ac.za
Phone
+27 11 559 4555