http://repository.mut.ac.ke:8080/xmlui/handle/123456789/6442 2026-04-21T01:06:52Z http://repository.mut.ac.ke:8080/xmlui/handle/123456789/6846 Understanding degradation of electroactive molecules in organic redox flow batteries: Decomposition analysis methods Nambafu, Godfrey Nakitare; Museveni, Sikukuu khwa; Kollongei, Naomi Organic redox flow batteries have attracted a lot of interests both in academics and industries. Accordingly, many organic materials and chemistries have been studied, providing a solid foundation for development of low-cost organic flow batteries. However, capacity loss/fade as a result of organic molecule decomposition/degradation is a major hindrance towards further advancement of this promising, sustainable and large-scale energy storage technology. Understanding the causes of decomposition as well as its mechanism is thus necessary to unravel this major challenge. Therefore, this perspective/views focus on highlighting the different methods that can be employed for decomposition assessment of organic molecules in flow battery systems. This will help in engineering and designing stable electroactive organic molecule to enable development of durable and long cycle life redox flow battery 2023-01-01T00:00:00Z http://repository.mut.ac.ke:8080/xmlui/handle/123456789/6845 Nutritional compound analysis and morphological characterization of spider plant (Cleome gynandra) - an African indigenous leafy vegetable Nambafu, Godfrey Nakitare; Omondi, Emmanuel O.; Engels, Christof; Schreiner, Monika Spider plant is among the important indigenous African leafy vegetables having the potential to contribute to food and nutritional security in sub-Saharan Africa. The main objective of this study was to quantify the mineral concentration, to identify and quantify glucosinolates and flavonoids in spider plant and further to characterize spider plant entries using important morphological traits. Thirty spider plant entries from different African countries, comprising of farmers' cultivars, gene bank accessions and advanced lines were grown in a field experiment and harvested for leaves, stems, flowers and siliques at different developmental stages. Five plant types based on the stem and petiole colorations were identified. Significant genotypic differences were shown for all the morphological traits except for 100 seed weight and silique weight. High mineral concentrations in the leaf tissue were observed especially for potassium, calcium, magnesium, phosphorus, iron, manganese and zinc. The aliphatic 3-hydroxypropyl glucosinolate was the main glucosinolate detected in all tissues with the highest concentrations in the reproductive organs. Glycosides of quercetin, kaempferol and isorhamnetin were the main flavonoids. Isorhamnetin glycosides were detected in trace amounts in both, leaves and inflorescences, while quercetin and kaempferol glycosides were the dominant flavonoids in the leaves and inflorescences, respectively. This knowledge of beneficial nutrient contents is an incentive for promoting spider plant consumption for improved human health while the morphological diversity analysis will be important for the further development of the spider plant germplasm. 2017-01-01T00:00:00Z http://repository.mut.ac.ke:8080/xmlui/handle/123456789/6844 Influence of soil phosphorus fertilizer forms on phosphorus uptake, morphology, and growth of leafy vegetables Nambafu, Godfrey Nakitare; Hoeppner, Nicolai; Onyango, Joseph Patrick Gweyi-; Andika, Darius O. Background Phosphorus (P) is an essential plant nutrient that has continued to depreciate in most soils in sub-Saharan Africa, mostly due to adsorption, leaching, and crop uptake. Objective This study was carried out to determine the effect of phosphorus forms and its absence on P uptake, root traits, and growth of leafy vegetables. Methods Five African indigenous vegetable species alongside one exotic vegetable were grown in pots. Each pot was supplied with 49 milligrams of P in the form of KH2PO4, Phytate, rock P, and FePO4 with the control having no P. The P fertilizers were mixed with 1220 g of soil in a ratio of 60:1, sand and loam, to fill the pots before planting. Vegetable seeds were randomly planted and replicated four times, giving rise to 120 pots under investigation. Results All vegetable species actively utilized KH2PO4 and Phytate to grow and form the highest shoot and root biomass. Spider plants absorbed high levels of P from all the P treatments, but could not convert more of it to biomass formation. African nightshade performed well in KH2PO4 and Phytate, but poorly in the rock P and FePO4. Cowpeas performed well by yielding high-shoot biomass in all the treatments. Cowpea and Ethiopian kale had high biomass when grown in rock P and FePO4. Conclusion Vegetable species require P for optimal growth, although various species were seen to have different levels of P uptake and utilization efficiency on soluble and slightly soluble fertilizers as well as their ability to grow in P-absent or adsorbed soils. 2025-01-01T00:00:00Z http://repository.mut.ac.ke:8080/xmlui/handle/123456789/6843 Levels of Cadmium, Copper, and Lead in Soils and Cassava Tubers Grown in Machakos County, Kenya Nambafu, Godfrey Nakitare; Kasyoka, E. M.; Mbugua, G. W.; Wanjau, R. N.; Ndiritu, J. N. Large quantities of agrochemicals are regularly applied in cofee farms to control pests and diseases and provide adequate nutrients to boost yields. Agrochemicals have varied amounts of heavy metals and their prolonged use to attain maximum yields contributes to the contamination of soil, surface, and groundwater. Te study determined the levels of lead, cadmium, and copper in soil and cassava tubers (Manihot esculenta) grown in single-cropped and intercropped farms in Kathiani Subcounty, Machakos County, Kenya. Soil and cassava tuber samples were obtained in a zigzag of fve cores across the farms. Cadmium, copper, and lead levels in the collected samples were determined using the atomic absorption spectrometer (AAS) Shimadzu AA-6200 model. Data were presented using tables and fgures. One-way ANOVA was used to examine the mean diferences of heavy metals between locations. Signifcant treatment diference was tested at α � 0.05 using the Tukey test. Te results revealed that soils from singlecropped farms had a range of 0.09–0.59, 4.1–4.6, and 0.021–0.032 mg·kg−1 for cadmium, copper, and lead, respectively, while soils from intercropped farms had a range of 0.25–0.83, 4.9–10.1, and 0.022–0.037 mg·kg−1 for cadmium, copper, and lead, respectively. Considering cassava tubers in the single-cropped system, the mean values (mg·kg−1 ) of Cd, Cu, and Pb for the pith were 4.7, 6.8, and 0.028, for the bark were 4.4, 4.3, and 0.02, and for the epidermis were 3.1, 4.0, and 0.02, while fesh had 2.6, 1.4, and 0.05, respectively. Analysis of the tubers in the intercropped system indicated that the pith had a mean value of 7.8, 7.0, and 0.20 mg·kg−1 for Cd, Cu, and Pb, respectively. Similarly, the bark had 5.8, 4.6, and 0.16 mg·kg−1 for cadmium, copper, and lead. Te epidermis indicated a concentration of 5.1, 4.6, and 0.12 mg·kg−1 for cadmium, copper, and lead, while the fesh had 2.8, 1.5, and 0.06 mg·kg−1 , respectively. Te results revealed the presence of heavy metals in both single-cropped and intercropped farms. Te observed means for cadmium, copper, and lead in both sets of farms were within the WHO recommended levels for agricultural soils. However, the study observed higher cadmium, copper, and lead levels in soils and cassava tissues from intercropped farms compared to single-cropped farms. 2024-01-01T00:00:00Z