Faculty of Science

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African knowledge on Endod (phytolaccadodecandra) and its potential for medicinal uses in Kenya
(University of British Columbia, Vancouver, BC, Canada, 2014) Ooko, SA.; Nashon, S.; Anderson, D.; Okeyo, JB.; Beru, F.; Okemwa, P.
The majority of people in Africa use plant based traditional medicines for their care. Demand for medicinal plants is increasing in Africa as the population grows. The threat posed by over-exploitation of medicinal plants has serious implications on the survival of several plant species, many of which are faced with extinction. The pharmaceutical potentials of African medicinal plants are immense. But constraints and challenges exist at all levels. This paper discusses these constraints and challenges in relation to conservation, science and technology, use of medicinal plants at the local level, the domestic drug production sector, marketing, safety and efficacy requirements. Measures and strategies for enhancing the development of a medicinal and aromatic plants industry in Africa are suggested.
Exploratory study on the impact of woodfuel use and planning strategies for its sustainability in Western Kenya
(University of British Columbia, Vancouver, BC, Canada, 2014) Beru, F.; Nashon, S.; Anderson, D.; Opata, P.; Ooko, S.; Okemwa, P.; Wafula, SS.
The impact of woodfuel collection on forests has been controversial and its role in rural livelihoods and deforestation is the subject of considerable debate. This study reviews the main dimensions of this discourse and the resulting responses form the forestry sector. It assesses new information that has come to light over the past decade, looking at national and global trends on woodfuel production and use and the evolution of patterns of urban and rural demand and supply. It examines livelihood and environmental dimensions of relevance to forestry and outlines some of the main issues that warrant additional attention. It is thus intended more as a foundation for further discussion, rather than being a set of prescriptions for action by forestry, though where these are evident they are identified. "The available evidence does not substantiate earlier concerns that woodfuel demand has been outpacing sustainable supply on a scale that makes it a major cause of deforestation. It appears the balance between the two seldom an issue requiring forestry intervention on a national scale. However, the rapid rise in charcoal production and its concentration, to supply large urban markets, certainly warrants further investigation. Overall, the woodfuels situation is an important consideration for particular areas within a country and for particular groups of users and suppliers. Globally, fuelwood consumption appears to have peaked (although charcoal consumption is continuing to rise) and in some developing countries, it now appears to be in decline. However, the total quantities of woodfuels being used, and the number of people using them, are still huge. In poor households almost everywhere, woodfuels are among the main forest related inputs, although the level of attention they receive does not currently reflect this, despite the growing focus on giving forestry a stronger livelihood orientation. Forestry initiatives need to be compatible with the energy sector’s objective of helping poor users move up the energy ladder to greater fuel efficiency and alternative fuels. The main task though, is likely to be facilitating access to supplies for those who continue to depend on biomass fuels, for their own use or as an important source of income. Forestry measures will need to integrate meeting this demand into wider forestry objectives, rather than, as in the past, developing responses focusing on the fuelwood issue alone."
Ecological Manipulation of Psidium guajava to Facilitate Secondary Forest Succession in Tropical Forests
(Journal of Ecological Engineering, 2020-10-01) Otuoma, John; Nyongesah, John Maina; Owino, Jesse; Onyango, Alice Adongo; Okello, Victor Samuel
Psidium guajava L. has been documented as an exotic invasive species in many parts of the world, but little is known about its interactions with native woody species during secondary forest succession in tropical forests. Its invasion and interactions with native species in different stages of secondary forest succession were assessed in Kakamega Rainforest in western Kenya. The study covered three forest blocks each with five different forest types, namely: open fields, young secondary forest, middle-aged secondary forest, old-growth secondary forest and disturbed primary forest, which served as the control. Open fields that were subjected to frequent clearing to control the spread of Psidium guajava remained under a thicket of the species two decades later. On the other hand, open fields where Psidium guajava was ignored, either due to lack of resources or sheer neglect, transformed into young secondary forest stands within a decade. The transformation increased woody species richness from 2.0±0.0 to 5.0±0.0 ha-1, and the Shannon diversity index from 0.30±0.33 to 1.10±0.01. It reduced the dominance of Psidium guajava from 80.5±22.7 to 62.26±0.84% and changed the canopy structure. The change in canopy structure led to the mortality of Psidium guajava stems in the sub-canopy and understory layer, which significantly reduced its stem density from 1,111±313 to 639.4±45 stems ha-1. The pattern was repeated in middle-aged secondary forest stands with woody species richness increasing to 26.0±8.2 ha-1, and Shannon index to 2.72±0.32. Psidium guajava’s dominance and stem density decreased further to 30.44% and 400.57 stems ha-1, respectively, due to mortality attributed to shading by native tree species. In the old-growth secondary forest, only snags of Psidium guajava were recorded. The species was not represented in the disturbed primary forest. The results indicate that Psidium guajava facilitates secondary forest succession by allowing shade-tolerant native tree species to recruit and grow in its shade. It is thereafter eliminated when the native species close the forest canopy. The species can be ecologically manipulated to facilitate post-disturbance forest regrowth and thereafter removing it when the forest canopy begins to close.
Radiological Measurement of Hazardous Levels in Construction Tiles in Bungoma County, Kenya
(Journal of Engineering and Technology for Industrial Applications, 2022-02-07) Nalianya, John Simiyu; Waswa, Michael Nakitare; Maingi, Francis M.; Wanyama, Conrad Khisa
Twenty (20) different local and imported tiles were sampled from major hardware’s in Bungoma. The samples collected were separately ground, sieved, through a 0.5mm mesh, dried at 110° C, weight and packed in a 200ml stoppered plastic bottles. The samples were stamped with identification numbers and kept for 30 days for secular equilibrium to be reached between the activity of 238U,232Th ,40K radium and their progeny. The average activity concentration of 238U, 232Th and 40K was found to be 109±5.48Bqkg-1, 11±0.55 Bqkg-1 and 1574±78.7 Bqkg-1 respectively. The average absorbed dose rate was found to be 140±7.03 nGyh-1 which is higher than the worlds average value of 60 nGyh-1. The average radium equivalent was found to be 288±14.44 Bqkg-1 which is lower than the world limit value of 370Bqkg-1. External and internal hazard indices were found to be 0.70±0.03 msvy-1 and 0.80±0.04 msvy-1respectively. Therefore, the sampled tiles used in Bungoma county for construction has minimal radiological threat to population.
Geopolymers Filters from Calcined Clay and Sugarcane Bagasse Blended with Activated Carbon for Removal of Selected Heavy Metals from Wastewater
(American Journal of Chemistry, 2022-10-08) Mwaura, D. M.; Mbuvi, H. M.; Maingi, Francis M.
The growth of industries and the exploitation of natural resources have led to increase of heavy metals concentrations in the earth’s surface, atmosphere and water bodies. Heavy metals pose serious environmental and health effects in the society since they are toxic and non-biodegradable. Removing heavy metals from aqueous solutions especially wastewater has become an area of study in the recent past. Various methods like ion exchange, reverse osmosis, coagulation and adsorption among others have been put forth in the removal of heavy metal ions. Geopolymers are zeolite analogues and there is little information on their use as water filters in literature. Incorporation of geopolymers and activated carbon to form wastewater filters have not been studied. This study focused on fabricating geopolymer filters derived from calcined clay and sugarcane bagasse ash incorporated with activated carbon for removal of heavy metals from aqueous media. Characterization of the Geopolymer, and activated carbon were done using XRF, XRD and FT-IR. Column adsorption using geopolymer/activated carbon filters was employed with Pb (II) and Cu (II) as the test heavy metal ions while varying concentration, filter thickness, and pH. Halo broad peaks were observed in the diffraction patterns at angle 2-theta between 20°- 34° in both geopolymer and activated carbon an indication that they were amorphous. Geopolymer: activated carbon ratio of 2:1, filter thickness of 4cm and pH range of 4-6.5 gave removal percentage of above 85% for both heavy metal ions. The experimental data fitted best in Freundlich adsorption isotherm with correlation coefficient (R2) of 0.854, 0.978 for Pb (II) ions, and Cu (II) respectively. Adsorption capacities of 0.028 mg/g and 0.015mg/g for Pb (II) ions, and Cu (II) ions were obtained respectively. The study shows that geopolymers/activated carbon filters have a potential of removing heavy metal ions from aqueous solution and hence can be applied for remediation of wastewater from industrial effluents.
Ways of Improving the Quality of Education in Primary Schools
(IRE Journals, 2024-03-28) Khakina, Peter Nyongesa; Munyekenye, Evelyne, N.; Maiyo, Julius K.
Quality education entails proper implementation of the curriculum's formal, non-formal, and informal dimensions. Quality education is reflected in performance in national examinations, where private schools tend to outperform public schools in Kenya. This study aimed to identify ways of improving the quality of education in primary schools by examining practices in private schools that contribute to their better performance. A sample of 13 head teachers, 56 teachers, and 405 students from 45 private schools in Bungoma County, Kenya, was used. Data were collected through questionnaires, interviews, and document analysis. The study concluded that ensuring sufficient teaching and learning resources, manageable class sizes, adequate staffing, teacher appraisal, and motivation are vital for improving the quality of education
Energy Efficiency Through Zero Energy House Construction Using Solar Technology in Bungoma County, Kenya
(IRE Journals, 2025-02-28) Khakina, Peter Nyongesa
A zero energy house is typically a house with net zero energy consumption on a yearly basis, which means that the annual energy consumption is equal to the amount of renewable energy produced on site. Bungoma County, Kenya has an average sunshine of about 9 hours in a day. The purpose of the study was to compare the consumption of power in a three bedroomed house within Bungoma County, Kenya when using grid power from Kenya Power and Lighting Company and solar energy in a zero-energy house. The power bills for 3 years were analyzed to determine the power consumption and the total cost. The consumption for the 3 years was 4,294 kWh at a total cost of Ksh. 106,090. For 20 years, the total cost of grid power will be Ksh. 707,267. The total cost of solar energy power in a similar three bedroomed zero energy house was calculated to be Ksh. 138,430 for a period of 20 years. Therefore, the cost of using solar energy was found to be about 20% of the grid power in Bungoma County, Kenya. The solar energy power is also environmentally friendly and ensures constant supply of power.
Factors Contributing to Mismatch Between Professional Training and Actual Work Done Among College and University Graduates in Kenya
(IRE Journals, 2025-03-28) Khakina, Peter Nyongesa
Professional training in Kenya is conducted in colleges and universities. Despite unemployment being a significant challenge, there is also the issue of mismatch between professional training and what is currently being done among graduates. The aim of this study was to identify factors that contribute to the mismatch between professional training and what graduates actually do. The research employed a survey methodology with a sample of 200 employees within the Western Kenya Region and 10 Chief Executive Officers of companies dealing in engineering works. Data was collected using questionnaires and interview schedules, and analyzed using percentages. Results confirmed a significant mismatch between training and actual work performed. Five key factors were identified: being forced by parents to pursue unwanted fields, inadequate training curriculum at colleges or universities, rapid technological changes, low remuneration, and peer influence. It is recommended that the Competence Based Curriculum be fully embraced and that training institutions enhance their curricula by incorporating technological changes and modern equipment. Career counseling should also be strengthened both during training and at the workplace to address these challenges.
Synthesis and characterization of cellulose phosphate-based superabsorbent hydrogels from rice husk under microwave heating
(Science Direct, 2025-06-07) Abdulhameed, Adamu; Mbuvi, Harun; Changamu, Evans; Githinji, Irene; Maingi, Francis M.
The current study deals with the synthesis and characterization of superabsorbent hydrogels from rice husk cellulose. Rice husks are slow decomposing waste from the milling of rice with an estimated composition of cellulose (50 %), lignin (25–30 %), silica (15–20 %), and moisture (10–15 %). The aim of using it as a source of cellulose was to provide an alternative use of the otherwise incinerated waste product that is abundantly available in rice producing countries like Kenya. Cellulose-based hydrogels continue to attract interest because of their biocompatibility and biodegradability for which they have found use in several fields including drug release, packaging films, agriculture, among others. The cellulose was extracted from rice husk and crosslinked with phosphoric acid under microwave oven heating. The products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, x-ray diffraction and x-ray fluorescence. Four parameters namely, heating time, microwave oven power out-put, percent swelling and the amount of cross-linker required for complete reaction were optimized for the synthesis of superabsorbent hydrogels. The optimum percentage swelling was found to be 877 %, heating time of 3 minutes, microwave oven power output of 420 watts (level 6 on the microwave oven dial), 10 mL of cross-linker when 2 g cellulose was used. The efficacy of the hydrogel in maize growing was determined by planting maize in pots in a greenhouse under varied hydrogel dose treatments and measuring growth and yield parameters over a period of twelve weeks. The values of plant growth and yield parameters were found to increase with hydrogel dose with the best results being observed among maize plants grown under the hydrogel dose of 5 g per pot. It was observed that the maize plants in pots treated with hydrogel continued to thrive while those in pots without any hydrogel dried off as expected when rains fail. These results are significant in that they demonstrate that rice husk cellulose-based hydrogels are efficacious in maize growing in a greenhouse.
Iron uptake in spinach (Spinacia oleracea) using biochar-iron complex derived from sugarcane bagasse under greenhouse conditions
(Journal of Scientific Agriculture, 2025-10-30) Kamaau, Meshack Mutungi; Mbuvi, Harun; Maingi, Francis M.
Iron deficiency limits spinach (Spinacia oleracea) growth and nutritional quality, particularly in alkaline soils. By investigating the complexation of iron with sugarcane bagasse-derived biochar, this study aimed to bridge that gap and offer insights into an innovative approach for improving iron nutrition in spinach crops. This study also evaluated the efficacy of sugarcane bagasse-derived biochar-iron complexes in enhancing iron uptake under controlled greenhouse conditions. Biochar-iron complexes were synthesized via pyrolysis and treated with iron (FeCl3) at 0.25 M, 0.50 M, and 0.75 M. In the greenhouse, using a Randomized Complete Design (RCD), the experiment compared treatments including FeCl3 only, biochar only and biochar-iron complexes at 0.25 M, 0.50 M, and 0.75 M concentrations against an untreated control. Iron uptake in spinach leaves was measured over three months using Atomic Absorption Spectroscopy (AAS). Infrared Fourier Transform Spectroscopy (FT-IR) analysis confirmed key functional groups involved in biochariron chelation, while X-Ray Fluorescence (XRF) revealed increased iron loading, peaking at 0.75 M. Analysis of variance from the greenhouse study revealed significant effects of treatment, time, and their interaction (p<0.001). Although the 0.75 M treatment produced the highest iron content (220 to 300 ppm), the 0.50 M biochar-iron complex is considered optimal, as it achieved iron levels within the FAO guideline range (80-250 ppm). In contrast, conventional FeCl3 treatment-maintained leaf iron at only 1.7-1.9 ppm throughout the three months, reflecting poor soil retention and rapid leaching of FeCl3. These findings highlight the composite’s superior magnitude and temporal stability of iron delivery. Sugarcane bagasse biochar–iron composite thus emerges as a promising, eco-friendly alternative to synthetic iron fertilizers for improving soil fertility and crop nutrition, addressing iron deficiency in sustainable food production.
Synthesis and Characterization of Superabsorbent Hydrogel from Activated Hydrochar-Sucrose Crosslinked with Maleic Acid
(Open Journal of Applied Sciences, 2026-01-30) Mukulu, Stanley M.; Mbuvi, Harun M.; Kasimu, Titus M.; Maingi, Francis M.
Superabsorbent hydrogels are hydrophilic materials forming three-dimensional polymer networks capable of absorbing large amounts of water. They are utilized in various fields, though most current types are non-biodegradable and costly to produce. This research explored a more sustainable approach by synthesizing superabsorbent hydrogels from activated hydrochar derived from sugarcane bagasse, using acidified potassium manganate for activation and sucrose for polymerization. Maleic acid was employed to create crosslinked structures, optimizing swelling capacity through varying conditions. Characterization through FT-IR confirmed successful crosslinkage. XRD analysis showed the amorphous nature of hydrochar and AH as compared to the increased crystallinity exhibited by AHSU polymer units and SAH superabsorbent hydrogel. SEM analysis revealed that the superabsorbent hydrogel had compact permeable surface network structures. The optimal synthesis ratio was found to yield a swelling capacity of 778% within 12 hours, highlighting the potential of these biocompatible hydrogels for agricultural applications in semi-arid and arid regions.

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