39624 research outputs found
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Adapting practicebased design research to a South African undergraduate architectural studio Building a more conscious and critical practice among students
No full textTribological and environmental impact of silicon dioxide nanoparticles in algae biodiesel fuels for diesel engines
No full textPreparation of hydrophilic PVDF membrane via blending with Fe3O4 nanoparticles and PVA for improved membrane performance in BTEX removal from wastewater
No full textA Retrospective Study Comparing Immunohistochemistry Subtyping and Findings on F-18 FDG PET/CT in Patients with Invasive Breast Cancer
No full textA research report submitted in fulfillment of the requirements for the Master of Medicine, in the Faculty of Health Sciences, School of Medicine, University of the Witwatersrand, Johannesburg, 2025INTRODUCTION: Breast cancer (BC) is a major global public health concern, and its diverse pathology makes management particularly complex. Molecular subtypes, identified through immunohistochemistry (IHC), along with metabolic activity and disease extent revealed by Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT), provide valuable insights. Exploring the relationship between IHC subtypes and F-18 FDG PET/CT findings can enhance personalized BC management.
AIM:
The study aimed to assess the correlation between IHC subtypes and F-18 FDG PET/CT findings in patients with invasive BC referred for staging, restaging, and response assessment at the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) Nuclear Medicine department.
METHOD: A retrospective analysis was conducted on histologically confirmed invasive BC patients who underwent F-18 FDG PET/CT between January 2016 and September 2022 at CMJAH. Patient demographics, IHC markers (ER, PR, HER-2, Ki-67%) on the initial histology, patterns of disease spread and SUVmax values of tumours on PET/CT were collected and analysed.
RESULTS: This study included 136 BC patients. FDG PET/CT was predominantly indicated for restaging (71%), followed by response to therapy assessment (18%) and staging (11%), detecting disease in 102 (75%) cases. Although not statistically significant, bone metastases were prevalent in hormone receptor-positive subtypes, while triple negative breast cancer (TNBC) showed a predilection for lung metastases. Higher Ki67% and standardized uptake value maximum (SUVmax) values, a marker proliferation and tumour aggressiveness, were significantly associated with TNBC subtype with a mean Ki67% of 70% (range, 40-80%) and SUVmax of 13.5 (range, 7.2-19), while Luminal A tumours exhibited the lowest values with a mean Ki67% of 10% (range, 5-20%) and SUVmax of 6.8 (range, 4.3-11). P-values of 0.0001 for Ki67% and 0.0564 for SUVmax.
CONCLUSIONS: vi The study highlights a significant correlation between IHC markers and FDG PET/CT imaging, particularly regarding the Ki67% and SUVmax, across different BC subtypes. These findings underscore the utility of FDG PET/CT not only in evaluating the disease extent—spanning local, nodal, and distant metastases—but also in complementing IHC analysis for a more comprehensive diagnostic approach, offering valuable insights that can guide clinical decision-making for personalized patient care. Future studies should incorporate prospective designs and novel PET tracers to overcome our current limitations.MM202
Sleep health epidemiology and associations with menstrual health mental health and educational performance among inschool female adolescents in Uganda A longitudinal study
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Geopolitical risk and energy market tail risk forecasting An explainable machine learning approach
No full textThe Role of South African Corporate Experience in the Transition from Intrapreneurship to Entrepreneurship
No full textA research report submitted in fulfillment of the requirements for the Master of Business Administration, in the Faculty of Commerce Law and Management, Wits Business School, University of the Witwatersrand, Johannesburg, 2025This study examines the transition from intrapreneurship to entrepreneurship among South African corporate professionals, exploring how they leverage corporate skills and tools to launch independent ventures. The study used a qualitative approach in semi-structured interviews to gather comprehensive insights. The study participants are individuals with experience in corporate who have transitioned into entrepreneurship or are currently transitioning into it. The findings of the thematic analysis highlight the opportunities, successes, and challenges of transitioning into entrepreneurship and discuss the tools intrapreneurs within corporations use in pursuit of entrepreneurship. Focusing on the South African context, the study identifies that supportive corporate cultures, financial resources, and effective mentorship significantly influence successful transitions. Recommendations are provided for corporate, policymakers and entrepreneurial support organisations, offering insights to foster a more conducive environment for South African entrepreneurs.MM202
Impact of low voltage ride through capability of IBT on voltage stability of an interconnected power system
No full textA research report submitted in fulfillment of the requirements for the Master of Science in Engineering, in the Faculty of Engineering and the Built Environment, School of Electrical and Information Engineering, University of the Witwatersrand, Johannesburg, 2025This research investigates the impact of the Inverter-Based-Technology (IBT) response during Low-Voltage-Ride-Through (LVRT) events on the classical P-V steady-state voltage collapse analysis. The response of the IBT Renewable-Energy-Sources (RES) during LVRT events has the form of a reduction in the IBT RES active-power export which is not considered in classical P-V steady-state voltage collapse analysis. The relationship between the transmission (Tx) voltage depression due to a fault on a Tx busbar and the IBT RES active-power export reduction is examined in this research. The classical P-V steady-state voltage collapse grid active-power transfer limits are compared between a conventional synchronous generator scenario (synchronous scenario) and a scenario where both synchronous generators and IBT RES are present (IBT RES scenario) using the Cigre Nordic voltage collapse test network. A novel prediction model is developed to approximate the IBT RES active-power reduction characteristic response to LVRT. Finally, it is shown that both the IBT RES LVRT active-power export response and the IBT RES LVRT reactive-power response impact the Tx-corridor active-power transfer limits and the Tx-corridor reactive-power export requirements not observed in the classical P-V steady-state voltage collapse analysis.MM202