https://repository.biust.ac.bw/handle/123456789/56 This collection is made up of research articles produced by both staff and post graduate students of BIUST community. 2026-04-19T17:04:27Z https://repository.biust.ac.bw/handle/123456789/735 Cohort study of adherence to adjuvant endocrine therapy, breast cancer recurrence and mortality Makubate, Boikanyo; Donnan, Peter; Dewar, John; Thompson, Andrew; McCowan, Colin Background: Adjuvant endocrine therapy is recommended for women with oestrogen receptor-positive breast cancer, but many women do not take the medication as directed and they stop treatment before completing the standard 5-year duration. Methods: This retrospective cohort study conducted between 1993 and 2008 of all women with incident breast cancer, who are residing in the Tayside region of Scotland, examined adherence to prescribed adjuvant tamoxifen or aromatase inhibitors (AIs). Survival analysis examined the effect of adherence on all-cause mortality, breast cancer death and recurrence, using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records. Results: A total of 3361 women with breast cancer were followed for a median 4.47 years (interquartile range (IQR) ¼ 2.04–8.55). The median overall adherence was 90% (IQR ¼ 90–100%), but the annual adherence reduced after a longer period from diagnosis. Low adherence of o80% was associated with poorer survival (hazard ratios ¼ 1.20; 95% confidence interval ¼ 1.03–1.40, P ¼ 0.019). There was no significant difference for low adherence over the treatment period and recurrence, or breast cancer death, but patients with high annual adherence for 5 years had better outcomes than those with 3 or less. Conclusion: Low adherence to all adjuvant endocrine therapy for women with breast cancer, whether tamoxifen or AI, increases the risk of death. 2013-03-21T00:00:00Z https://repository.biust.ac.bw/handle/123456789/719 Dual carbonate clumped isotope (Δ47-Δ48) measurements constrain different sources of kinetic isotope effects and quasi-equilibrium signatures in cave carbonates Parvez, Zeeshan A; El-Shenawy, Mohammed I; Lucarelli, Jamie K; Sang-Tae, Kim; Johnson, Kathleen R; Wright, Kevin; Gebregiorgis, Daniel; Montanez, Isabel P; Wortham, Barbara; Asrat, Asfawossen; Reinhardt, Eduard; Christensen, John N; Matamoros, Irvin W; Rubi, Joshua; Miguel, Kevin; Elliott, Ben M; Flores, Randy; Kovacs, Shawn; Eagle, Robert A; Tripati, Aradhna Cave carbonate minerals are an important terrestrial paleoclimate archive. A few studies have explored the potential for applying carbonate clumped isotope thermometry to speleothems as a tool for constraining past temperatures. To date, most papers utilizing this method have focused on mass-47 clumped isotope values (Δ47) at a single location and reported that cave carbonate minerals rarely achieve isotopic equilibrium, with kinetic isotope effects (KIEs) attributed to CO2 degassing. More recently, studies have shown that mass-47 and mass-48 CO2 from acid digested carbonate minerals (Δ47 and Δ48) can be used together to assess equilibrium and probe KIEs. Here, we examined 44 natural and synthetic modern cave carbonate mineral samples from 13 localities with varying environmental conditions (ventilation, water level, pCO2, temperature) for (dis)equilibrium using Δ47-Δ48 values, in concert with traditional stable carbon (δ13C) and oxygen (δ18O) isotope ratios. Data showed that 19 of 44 samples exhibited Δ47-Δ48 values indistinguishable from isotopic equilibrium, and 18 (95 %) of these samples yield Δ47-predicted temperatures within error of measured modern temperatures. Conversely, 25 samples exhibited isotopic disequilibria, 13 of which yield erroneous temperature estimates. Within some speleothem samples, we find Δ47-Δ48 values consistent with CO2 degassing effects, however, the majority of samples with KIEs are consistent with other processes being dominant. We hypothesize that these values reflect isotopic buffering effects on clumped isotopes that can be considerable and cannot be overlooked. Using a Raleigh Distillation Model, we examined carbon and oxygen isotope exchange trajectories and their relationships with dual clumped isotope disequilibria. Carbon isotope exchange is associated with depletion of both Δ47 and Δ48 relative to equilibrium, while oxygen isotope exchange is associated with enrichment of both Δ47 and Δ48 relative to equilibrium. Cave rafts collected from proximate locations in Mexico exhibit the largest average departures from equilibrium (ΔΔ47¯ = −0.032 ± 0.007, ΔΔ48¯ = −0.104 ± 0.035, where ΔΔi is the measured value – the equilibrium value). This study shows how the Δ47-Δ48 dual carbonate clumped isotope framework can be applied to a variety of tcave carbonate mineral samples, enabling identification of isotopic equilibria and therefore quantitative application of clumped isotope thermometry for paleoclimate reconstruction, or alternatively, constraining the mechanisms of kinetic effects. 2024-11-27T00:00:00Z https://repository.biust.ac.bw/handle/123456789/718 Sustainable bio-coagulant from moringa oleifera seed extract for water treatment application Zviuya, Amanda; Govha, Joseph; Sigauke, Placxedes; Mamvura, Tirivaviri A.; Danha, Gwiranai This study focused on producing a natural bio-coagulant from moringa seeds. Moringa seed extract is a natural coagulants for the treatment of water containing suspended solids and colloids and is obtained through grinding, oil extraction, protein extraction from the solids using 2M NaCl solution, protein separation by centrifugation followed by filtration. This study investigated production and use of bio-coagulant. Parameters investigated when producing the bio-coagulant include effect of temperature on the removal of moisture content in the moringa seeds, effect of the type of solvent on the oil yield and effect of varying the volume of n-hexane for oil extraction. Parameters investigated when using the bio-coagulant include effect of dosage of bio-coagulant on pH and turbidity removal efficiency, and the performance of the bio-coagulant at low, medium and high turbidity levels. The optimum temperature obtained by drying the moringa seeds was at 100 oC and the highest oil yield obtained was 31 % when using n-hexane as the solvent. Turbidity removal efficiency went up to 96 % when using 40 mg/L of the bio-coagulant at a pH of 6.1. High turbidity removal was achieved at low bio-coagulant dosages which was regarded as a breakthrough finding for this research. 2025-05-01T00:00:00Z https://repository.biust.ac.bw/handle/123456789/717 Effect of fabrication techniques of high entropy alloys: A review with integration of machine learning Salam, Mohamed Yasin Abdul; Ogunmuyiwa, Enoch Nifise; Manisa, Victor Kitso; Yahya, Abid; Badruddin, Irfan Anjum High Entropy Alloys (HEAs) are an emerging class of materials distinguished by equimolar or near-equimolar compositions of five or more principal elements. HEAs display exceptional mechanical properties, thermal stability, and wear resistance, making them suitable for advanced aerospace, biomedical, and automotive engineering applications. This review thoroughly explores various fabrication techniques for HEAs, including Vacuum Arc Melting (VAM), Hot Compression (HC), Laser Cladding (LC), and Spark Plasma Sintering (SPS). Each method's advantages, limitations, and impacts on microstructural properties are discussed in detail. Additionally, the integration of Machine Learning (ML) techniques in HEA research is highlighted, demonstrating their potential for optimizing fabrication parameters and predicting phase stability, microstructure evolution, and mechanical properties. The review concludes by identifying challenges in HEA fabrication, such as data availability and sustainability, and proposes future research directions to address these gaps. This work aims to provide researchers and engineers with a consolidated resource for advancing the development and application of HEAs. 2025-03-01T00:00:00Z