MST-School of Pure and Applied Sciences

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This collections contains bibliographic information and abstracts of Master theses and dissertation in the School of Pure and Applied Sciences held in Kenyatta University Library

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    A Comparative Study of Hepatitis B Virus among In-Mates and Low Risk Voluntary Blood Donors in Garissa County, Kenya
    (Kenyatta University, 2024-07) Odallo, Vincent Bahati
    Hepatitis B virus (HBV) infection is a life-threatening infection that attacks the liver and can cause both acute and chronic disease. This creates a high risk of death from cirrhosis and liver cancer. Hepatitis B infection poses a major health concern globally. It is estimated that in 2019, about 296 million people had been chronically infected with HBV globally and about 820, 000 deaths from hepatocellular carcinoma and cirrhosis were reported. In Kenya, HBV prevalence stands at chronic states of intermediate range (5-7%) and high (≥8%) with regional variations. Garissa County carries a high HBV infection risk with a reported prevalence of 14.1% in pregnant women attending antenatal care (ANC) clinics. This study sought to determine the seroprevalence and circulating Hepatitis B virus genotypes among the prisoners and compare it with that of the surrounding general population at Garissa Main Prison and Garissa County Referral Hospital respectively in Garissa, Kenya. A total of 130 in-mates and 130 voluntary blood donors were sampled in this study and a questionnaire used to collect data on their socio-demographic characteristics. Blood was then collected in plain vacutainers and the resulting serum tested for Hepatitis B surface antigen (HBsAg) using a rapid test strip. HBV DNA was then extracted from the serum and a 930bp region of the overlapping P/S gene amplified and sequenced. Logistic regression was used to evaluate socio-demographic factors associated with HBV seropositivity. Resulting HBV DNA sequences were manually edited, assembled into contigs and then aligned. Genotype identity of the aligned sequences was initially made using the Geno2pheno [hbv] 2.0 online data base. The aligned sequences from this study and genotype specific sequences in Genbank were then used to infer phylogenetic relationships of the local strains. The Geno2pheno [hbv] 2.0 online data base was further used to identify mutations in the samples associated with diagnostic failure and vaccine failure (in the S gene) and antiviral resistance (in the P gene). Majority of the study participants were males (86.9% among inmates and 95.4% among blood donors. Majority (76.2%) of the in-mates and of the donors (83.1%) were aged between 20-40 years while majority (51.4 % of the donors and 81.5% of in mates) had only a primary school level of education. HBV seroprevalence was significantly higher among in-mates compared to blood donors. Out of the total number of in-mates tested, 7 (5.4%) were HBV seropositive. Conversely, among blood donors 4 (3.1 %) were seropositive. There was a significant association between HBV seropositivity and gender among both the blood donors and in-mates. Out of the 22 HBV-DNA positive samples, genotype D was the most prevalent among both the in-mates and blood donors (81.8%). Genotype A sub-genotype A1 was only detected among the in-mate population (18.2%). All the genotype D sequences were found to be either D/A or D/E recombinants. HBsAg escape mutations associated with diagnostic failure were noted among both study populations. As a pioneer study on HBV in Kenyan prisons, the current study confirms the categorization of in-mates as HBV high risk populations. The dominance of HBV genotype D is a novel finding as studies in other regions of the country have identified genotype A as the most prevalent. Further studies should be carried out in other regions to determine circulating HBV genotypes and HBsAg escape mutations that may influence HBV infection diagnosis and treatment outcome in those regions.
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    A prey predator conservation model for a fishery with a reserve area and prey refuge: a study of Lake Victoria
    (Kenyatta University, 2024-09) Wasike, Silas Were
    Overfishing and predation are causing loss of species in most fisheries worldwide and now most endemic fish species are on the brink of extinction. This threatens biodiversity and sustainability of these fisheries. Despite the many mitigation measures by the Kenyan government to address the decline of fish species in Lake Victoria, the decline continues unabated. A major decline has been observed in haplochromines (fulu) due to predation by Nile perch (mbuta) and the species is now in danger of extinction. There is need for research to enrich conservation practices for the fishery. To understand the preypredator dynamic system of the Nile perch and haplochromines, we have formulated and analyzed a two species prey-predator conservation model with a reserve area and prey refuge. The model is formulated using a logistic nonlinear differential equation which describes a self-limiting growth of a biological population and incorporates Holling type II functional response of the predator towards the prey. The fishery ecosystem is divided into two zones, the protected reserved area and the unreserved area. Scaling down the parameters of the equations was done to reduce the number of parameters for easier analysis of equilibrium points. The study aims to determine the positivity and boundedness of the model, the stability of equilibrium points, conditions for their existence and the effect of a reserve area on the stability of the system. Analysis of the model has been done, equilibrium points and conditions for their existence determined. The stability of equilibrium points both locally and globally has been established. To assess the effect of a reserve area on stability of the population of the system, numerical simulations in MATLAB using known parameters was done. This was done by variation of some parameters and the time series solutions drawn. The results showed that the reserved area has a stabilizing effect on the prey-predator dynamic system
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    A Quantile Regression Approach to Modeling and Predicting Geothermal Well Drilling Costs
    (Kenyatta University, 2025-06) Kizambo, Eric Kachila
    Several factors influence cost of drilling a geothermal well. The most common ones consist drilled depth, type of drilling method used, drilling time, non-productive time among others. Accurate cost estimation is critical for a project’s planning and financial viability. In current practice, most drilling cost models estimate cost solely as a function of drilled depth. However, these models often overlook other critical factors such as drilling time and non-productive time that significantly influence drilling costs. Consequently, the models relied on do not explain the full range of variation in cost. Ordinary Least Squares (OLS) regression has been a widely used method for modeling drilling cost as a function of explanatory variables. However, the estimators derived from OLS are highly sensitive to outliers, which can significantly distort predictions and reduce the model’s robustness in the presence of non-normal error distributions. The objective of this study was to develop a robust model for estimating geothermal well drilling costs by incorporating key predictors that were previously overlooked using a quantile regression approach. The study accounted for the varying impact of predictors across different points of the cost distribution. This method offered a more comprehensive understanding of cost drivers and provided robust estimates that are less sensitive to outliers compared to traditional mean-based regression techniques like Ordinary Least Squares (OLS). Data from the Menengai geothermal project in Nakuru county was used in the study. The data comprised drilling data of 52 wells drilled between 2011 and 2019. The findings reveal significant correlations between drilling cost and both drilling time and non-productive time. Quantile regression analysis demonstrated that the impact of these covariates varies across the 0.25, 0.5, and 0.75 quantiles, with non-productive time exerting a more substantial influence on higher-cost wells. Compared to traditional Ordinary Least Squares (OLS) regression, quantile regression provides a more detailed understanding of the cost drivers. The model's coefficients for drilling time and non-productive time at different quantiles indicate that Drilling cost sensitivity varies, underscoring the importance of using quantile regression for more accurate and tailored cost estimations in geothermal drilling. The proposed model outperforms the traditional Ordinary Least Squares (OLS) approach, offering improved predictive power and more nuanced insights into cost determinants.
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    A Study of MHD Fluid Flow Bounded by two Parallel Vertical Plates in A Porous Media with Heat Transfer
    (Kenyatta University, 2025-05) Kariuki, John King’ori
    The study investigated a Newtonian Magneto-hydrodynamic fluid flow bounded by two parallel vertical plates in a porous media with heat transfer. The fluid was considered to be flowing uniformly in the x-direction. The parallel vertical plates are impermeable and a transverse magnetic field is applied perpendicular to the plates in the positive y-direction. The plates are heated and kept at constant temperature 𝑇𝑇𝑤𝑤 and the distance between the two plates was varied. The fluid and the porous matrix are approximated to have the same temperature, 𝑇𝑇𝑓𝑓 . The effect of varying Darcy number, Hartmann number, Prandtl number, and Reynolds number on velocity and temperature profiles was discussed. The coupled non-linear PDE governing the fluid flow were non-dimensionalized to obtain a dimensionless equation. The resulting equation was discretized using the finite difference method to obtain non-linear algebraic equations which were solved using MATLAB. The obtained results were presented in graphs and then discussed. It was observed that velocity profile decreased when Hartmann number or Reynolds number was increased. On the other hand, velocity profile increased after increasing Prandtl number or Darcy number. It was also observed that temperature profile decreased when Hartmann number or Prandtl number was increased. On the other hand, temperature profile increased when Reynolds number or Darcy number was increased. These results have applications in aerodynamic heating and motor vehicle cooling.
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    Abundance and Conservation Status of Prunus Africana in Western Mau Forest, Kenya
    (Kenyatta University, 2020-03) Chebet, Gladys
    Prunus africana (Hook. f) Kalkman, 1965 (formerly Pygeum africanum Hook.f) is a geographically widespread tree restricted to highland forest of main land Africa and outlying islands. The species is commercially important for its bark, which is used in the treatment of prostate gland disorders. It also produces high quality timber used locally for building poles and furniture as well as fuel wood. The high demand for the bark has led to notable destruction of the species in natural forests, leading to concerns on the long term sustainability of harvesting and the conservation of the species. Despite the fact that Mau forest is a protected area, the region experiences illegal exploitation with P. africana being one of the main targets. The tree is of great demand for its strong timber and highly medicinal bark making its population to be under threat. As a result P. africana is listed as vulnerable species under Appendix II of CITES. In this study, information on P. africana was obtained mainly from literature survey while population data was obtained by sampling methods. The study was conducted in Western Mau forest (longitude E35027.05’ to E35039.42’ and latitude 0010’46’’S to 0017’42’’S) which is found in the South Rift region, Kericho county. Transects were laid across four blocks in Western Mau forest and diameter at breast height (dbh) and height of mature trees measured. The level and causes of disturbances were collected using questionaires and through observation and recorded for each of the plots. Saplings were counted and recorded in subplots and seedlings counted in micro plots. Densities of seedlings, saplings and mature P. africana trees were examined across the Western blocks of Mau forest. A socio-economic survey was further conducted to determine community perceptions on the status of the tree under study. The data generated were analyzed using both descriptive and inferential statistics. Data on height and dbh were summarized as mean ± SE and variations tested using one way ANOVA. Socio-economic data were mainly analyzed in form of proportions and variations between sites tested using chi-square statisctics.Data was presented in histograms, tables and graphs. Inferential statistics revealed significant variation in the density of saplings (p<0.05). Majority of the mature trees were of height between 20m and 40m though this height varied significantly between the blocks. As concerns dbh, most of the trees ranged between 40cm and 50cm with a signigficant variation between the blocks. The seedling numbers exceeded saplings and trees, suggesting potential for regeneration and population increase even though the population is not increasing. Observations showed that human activities, herbivory and diseases pose serious threats to P. africana tree. The local community was of the opinion that the main anthropogenic activities affecting the tree are unsustainable de-barking, logging, and animal grazing. It was recommended that awareness creation be organized regularly for all stakeholders on sustainable de-barking and logging be greatly regulated to save this tree of great value to mankind. The local community and more so those who rely on the tree for herbal medicine should be encouraged to grow the tree in their homestead gardens to reduce the pressure on wild trees thereby enhancing its conservation.
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    Abundance, genetic diversity and symbiotic potential of common bean (phaseolus vulgaris l.) nodule associated bacteria in Western Kenya soils
    (Kenyatta University, 2016-07) Simiyu, Wekesa Clabe
    Plant growth-promoting rhizobacteria (PGPR) are beneficial native soil bacteria that colonize plant roots and result in increased plant growth. Those that colonise the nodules of legumes are known as nodule associated bacteria (NAB). The aim of this study was to determine the distribution and genetic diversity of NAB that colonize Phaseolus vulgaris, their abundance, and symbiotic efficiency when coinoculated with Phaseolus vulgaris in Western Kenya soils. The soil samples were collected from cultivated lands in Kisumu near Lake Victoria, slopes of Mt. Elgon and Kakamega. In each of these regions, the soil samples were collected from four regions. 1ml of soil solution at 10 fold dilution for seven dilution steps (10-1 to 10-7) and three replications for each dilution was used to inoculate common bean seedling in Leonard jars. They were harvested after four weeks to determine abundance of NAB using most probable number method. Common bean nodules were also collected directly from the farmers’ farms in the above three regions. Harvested nodules and those collected from the field were cleaned and surface sterilized, crushed and exudates streaked on YEM agar growth media. Pure colonies were further cultured in YEM broth at 280C for three days and the genomic DNA isolated from the bacteria using Qiagen DNA extraction kit. 16SrRNA gene was amplified by 27F and 1492R primers and PCR products resolved by agarose gel electrophoresis and sequenced. 16SrRNA gene analysis revealed that NAB that nodulate with common beans are genetically diverse as they formed clusters on the phylogenetic tree and their distribution depends on chemical characteristics of the soil. BLASTn showered that isolated strains belonged to the genus Pseudomonas, Providencia, Rhizobia, Klebsiella, Sphingobacterium, Enterobacter, Delfitia, Acinetobacter and one strain did not have sequence homology at the GenBank. Mt. Elgon region had the highest population of NAB (120000 cells per gram of the soil), followed by Kisumu (1290 cells per gram of the soil) and Kakamega region had the lowest (17 cells per gram of the soil). The effect of PGPR on the yield of common beans was significantly higher (p < 0.001) when co-inoculated with Rhizobia compared to the yield of Rhizobia inoculated alone or control (not inoculated) (p < 0.05). This study therefore provides knowledge on the type of NAB that nodulates with common beans and factors that favour their distribution necessary for production of PGPR inoculants suitable to the soils of Western Kenya.
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    Accidents as an occupational health problem - a case of Babadogo industrial area Nairobi - Kenya
    (2012-02-28) Otieno, Samwel Boaz
    An investigation of occupational accidents among factory workers was carried out in Babadogo Industrial Area in carried out in Babadogo Industrial Area in Ruaraka -Nairobi, between September 1998 and December 1998. In this cross sectional study a total of 300 workers were interviewed in 18 factories selected randomly. The data was coded and analyzed by Statistical Programme for Social Scientists (SPSS) (1998) program. It was shown that 93% of the factories in Babadogo Industrial Area were in general consumer and service manufacturing category (P < 0.001) with most of the workers (83.33%) being males (P < 0.001) and only 58.4% having post secondary and primary school training. The investigation also revealed that up to 47.2% of respondents have had occupational accidents in the previous twelve months under study. Of the injured workers 45.4% have only had accidents once while 2.8% have had accidents at least 15 times or more (P < 0.001). At least 38% of the injured workers did not report accidents to their employers. It was also shown that there was a strong association between the causes of accidents and occupations (P < 0.001) with handling objects being responsible for 39.6% of all accidents. Accidents rates were also shown to vary with experience (P < 0.025) with most accidents. (51.2%) occurring in those who have worked for 5 years or less. Within each occupation type accident rates were varied with most accidents affecting machine operators. The differences in accident rates of different occupations was found to be significant (P < 0.001). It is also shown that accidents rates vary with time of the day with peaks at 12.00 noon (18.1%) and at 3.00 p.m. (21.0%), however there was no significant differences, in the rates between morning and afternoons (P > 0.05). The investigation also revealed that accident rates varied with day of the week with most accidents, (24.4%) occurring on Wednesday. The variation was also shown to occur by the month with most accidents (22.5%) occurring in the month of August. Investigation also showed significant variation in several aspects of safety standards (P < 0.001) housekeeping standards (P < 0.001) and presence of several physical and chemical hazards within the work environment, details of which are given in the text. This study revealed that handling objects; hand tools and power driven machinery caused most of accidents. Much attention should therefore be focused towards these causes in order to reduce accidents. If further revealed that machine operators had higher rate of injuries compared to other occupations hence much attention should be given focused on training and improvement of production on machinery in order to reduce accidents. It was also shown that a significant number of workers had low level of education hence attention should be given to training of workers, as this could be a contributing factor in accident causation as most of the workers injured were machine operators hence the employees should be involved in ergonomic design were of machine. Much attention in form of education of workers should be given to particular time of machines. Much attention in form of education of workers should be given to particular time of day (12 noon) and (3.00 p.m.) and to Wednesdays, as most accidents tended to occur during that time. Housekeeping standards, safety standards and chemical and physical hazards level were shown to be the significant factors, hence much attention should also be focused in work environment improvement as this could reduce the number of accidents.
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    Action of Symmetric Group S5 on The Cosets of Some of Its Non-Maximal Subgroups
    (Kenyatta University, 2020-07) Omori, Kerubo Lydiah
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    The Action of Symmetry Groups of Platonic Solids on their Respective Vertices
    (Kenyatta University, 2020) Waweru, R. Brian
    Platonic solids are 3-dimensional regular, convex polyhedrons. Each of the faces are equidistant and equiangular to each other in any of the solids. They derive their name from the ancient Greek philosopher, P lato who wrote about them in his dialogue, the Timaeus as reported by Cornford (2014). The solids features have fascinated mathematicians for decades including the renown geometer, Euclid: In his Book XIII of the Elements, as rewrote by Heath et al. (1956), he successfully determined the exact number of solids that qualify to be Platonic Solids; tetrahedron, cube, octahedron, dodecahedron and icosahedron. In group theory, the symmetry group of an object is the group of all transformations under which the object remains unchanged, endowed with the group operation of composition. Due to their inherent symmetry of these solids many mathematicians have attempted to derive their symmetry groups. For instant, Foster (1990) who successfully enumerated the symmetry groups of the dodecahedron and recently Morandi (2004) attempted to compute these symmetric groups of the solids using a computer program called Maple. Although such contributions are noteworthy, a few attempts have been made to explore other features such as the symmetry groups of the platonic solids. Thus, this project investigates the properties of the group action of the symmetry groups of these platonic solids acting on their respective vertices. We embark on constructing the symmetry groups of each of the solids then employ the orbit-stabilizer and other theorems to determine the ranks and sub-degrees of each solid. The action of G on V shows that tetrahedron has a rank of 2, the octahedron has a rank of 3, dodecahedron has a rank of 6 while the cube and icosahedron have a rank of 4.
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    Adaptation of an enzyme-linked immunosorbent assay for determination of diminazene aceturate in goat serum and tissue residues of animals
    (2011-11-08) Karanja, Wycliff Maina
    The importance of food safety through the reduction of residues in our food supply cannot be overemphasized. Food safety remains a major challenge confronting contemporary society. Analytical methods are needed to generate the data on which dietary exposure assessments are based and to enforce statutory maximum residue limits (MRLs) that are set. Diminazene aceturate is one of the few drugs used for animal trypanosomosis. Because of it's wide use in livestock, the risk of unwanted residues in edible products may exist. A competitive enzyme-linked immunosorbent assay (ELISA) for determination of diminazene residues in edible animal tissues after extraction in 0.1 M borax at pH 9.7 was investigated. The assay used rabbit anti-diminazene polyclonal antibody on the solid phase support. Horseradish peroxidase-labeled diminazene was incubated with sample overnight at 4°C. After five washes with buffer enzyme activity was determined by adding tetramethyl-benzidine and hydrogen peroxide as substrate. The resulting blue colour whose intensity was inversely proportional to the drug concentration changed to yellow when the reaction was stopped by addition of 0.1 M orthophosphoric acid. The assay was optimized and validated for determination of diminazene in tissues. The assay exhibited high specificity (99.997%) for diminazene recognizing only isometamidium at 0.003% and this may be contributed by the amidinophenyl that is common in both drugs. Recoveries from spiked tissues were above 77% while Dilutional parallelism experiments demonstrated a recovery of 96.0% ± 9.5%. The limit of detection (LOD) for the assay was 2.4ng/g for muscle, 2.5ng/g for liver and 2.2ng/g for kidney while limits of quantification (LOQ) were 5.51 ng/g, 4.11 ng/g and 3.74 ng/g respectively. The LODs are 4.4x103 to 3.5xl03 lower than the MRLs that are 500mg/kg, 12,000m/kg and 6,000mg/kg of muscle liver and kidney respectively. Assay precision was characterized by a within assay coefficient of variation (CV) of 2.4% and between assays CV of 15.5%. When diminazene was administered intramuscularly at 3.5mg/kg to five goats that were sacrificed seven days later, the mean diminazene residue levels were 0.75mg/g±0.14mg/g for skeletal muscle, 32.05mg/g±5.7mg/g for liver and 4.29mg/g±0.66mg/g for kidney. The analysis of tissue samples collected from slaughterhouses around Nairobi showed that out of 35 muscle samples, only one was positive and had a diminazene concentration of 0.039 !ig/g. Four out of 32 kidney samples were positive for diminazene with levels of 0.63, 1.66, 2.61 and 3.96mg/g. From ten liver samples two were positive with levels of 1.07 and 1.74pg/g. From this analysis none of the positive samples had levels above the MRL values. This study has demonstrated that competitive ELISA can be employed for the determination of diminazene residues. The results of this study are relevant to food scientists, toxicologists and analysts working in the area of detection and safety assessment of food residues, companies developing veterinary drugs, regulatory bodies involved in safety assessment of veterinary drugs and residue monitoring and to regulatory bodies responsible for veterinary drugs registration.
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    Adaptation of an enzyme-linked immunosorbent assay for determination of diminazene aceturate in goat serum and tissue residues of animals
    (2014-11-27) Karanja, Wycliff
    The importance of food safety through the reduction of residues in our food supply cannot be overemphasized. Food safety remains a major challenge confronting contemporary society. Analytical methods are needed to generate the data on which dietary exposure assessments are based and to enforce statutory maximum residue limits (MRLs) that are set. Diminazene aceturate is one of the few drugs used for animal trypanosomosis. Because of it's wide use in livestock, the risk of unwanted residues in edible products may exist. A competitive enzyme-linked immunosorbent assay (ELISA) for determination of diminazene residues in edible animal tissues after extraction in 0.1 M borax at pH 9.7 was investigated. The assay used rabbit anti-diminazene polyclonal antibody on the solid phase support. Horseradish peroxidase-labeled diminazene was incubated with sample overnight at 4°C. After five washes with buffer enzyme activity was determined by adding tetramethyl-benzidine and hydrogen peroxide as substrate. The resulting blue colour whose intensity was inversely proportional to the drug concentration changed to yellow when the reaction was stopped by addition of 0.1 M orthophosphoric acid. The assay was optimized and validated for determination of diminazene in tissues. The assay exhibited high specificity (99.997%) for diminazene recognizing only isometamidium at 0.003% and this may be contributed by the amidinophenyl that is common in both drugs. Recoveries from spiked tissues were above 77% while Dilutional parallelism experiments demonstrated a recovery of 96.0% ± 9.5%. The limit of detection (LaD) for the assay was 2.4ng/g for muscle, 2.5ng/g for liver and 2.2ng/g for kidney while limits of quantification (LOQ) were 5.51ng/g, 4.11 ng/g and 3.74 ng/g respectively. The LaDs are 4.4x103 to 3.5x103 lower than the MRLs that are 500llg/kg, 12,000Ilg/kg and 6,000Ilg/kg of muscle liver and kidney respectively: Assay precision was characterized by a within assay coefficient of variation (CV) of 2.4% and between assays CV of 15.5%. When diminazene was administered intramuscularly at 3.5mg/kg to five goats that were sacrificed seven days later, the mean diminazene residue levels were 0.75Ilg/g±0.14Ilg/g for skeletal muscle, 32.05Ilg/g±5.7Ilg/g for liver and 4.29Ilg/g±0.66Ilg/g for kidney. The analysis of tissue samples collected from slaughterhouses around Nairobi showed that out of 35 muscle samples, only one was positive and had a diminazene concentration of 0.039 ug/g. Four out of 32 kidney samples were positive for diminazene with levels of 0.63, 1.66,2.61 and 3.96Ilg/g. From ten liver samples two were positive with levels of 1.07 and 1.74 ug/g. From this analysis none of the positive samples had levels above the MRL values. This study has demonstrated that competitive ELISA can be employed for the determination of diminazene residues. The results of this study are relevant to food scientists, toxicologists and analysts working in the area of detection and safety assessment of food residues, companies developing veterinary drugs, regulatory bodies involved in safety assessment of veterinary drugs and residue monitoring and to regulatory bodies responsible for veterinary drugs registration.
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    Adoption of biogas technology as an alternative energy source in Gakawa Location, Nyeri County, Kenya
    (Kenyatta University, 2018) Otondi, Ronald Nyakweba
    Tsetse flies (Glossina spp.) are vectors of Animal African Trypanosomiasis and Human African Trypanosomiasis. Two approaches have been used to combat the diseases: parasite and vector control. Parasitic control by trypanocidal drugs has so far failed due to problems of availability, toxicity and resistance development. Vector control by use of insecticides is ineffective. Trapping using baits have been relatively successful, except among pastoralists. Integration of repellants and attractants to create push-pull strategy may provide an effective control tactic at individual farmer and pastoralist level. A previous study on waterbuck, led to the identification of a blend of 15 electrophysiologically active constituents: six C8-C13 methylketones, two phenolic compounds, six C5-C10 fatty acids and δ-octalactone that is repellant to savanna tsetse flies. δ-Octalactone has been shown to singly elicit allomonal responses, and a follow-up study has shown that its structural modification can bear both repellants and attractants. In the present study, the effects of some δ-octalactone analogues on two Glossina spp. were carried out to elucidate their activities. (RS)-3-propylcyclohexanone (15) and (RS)-δ-valerolactone (16) and were synthesized and their structures confirmed using spectroscopic techniques, while 2-propyloxane (14) and (RS)-3-propylcyclohex-2-enone (17) were acquired commercially. The responses of the two Glossina spp. to each of the four analogues were determined in a two-choice wind tunnel. Data collected were subjected to Analysis of Variance and means ranked using Student-Newman-Keuls test and the tsetse preferences were compared using t-Test. In the bioassays, it was noted that (RS)-δ-valerolactone (16) and (RS)-2-propyloxane (14) elicited avoidance; whereas (RS)-3-propylcyclohex-2-enone (17) and (RS)-3-propylcyclohexanone (15) elicited attraction. There was no significant difference between the repellency of (RS)-δ-valerolactone (16) and 2-propyloxane (14) (p > 0.05) to both Glossina spp. However, the repellency of both, (RS)-2-propyloxane and (RS)-δ-valerolactone, were significantly lower than that of δ-octalactone (5) (p < 0.05). When (RS)-δ-valerolactone (16) and (RS)-2-propyloxane (14) were blended it was noted that the repellency was comparable to that of δ-octalactone (5) (p > 0.05) when G. pallidipes were deployed, but there was no significant improvement in repellency against G. m. morsitans. The attractancy of (RS)-3-propylcyclohex-2-enone (17) and (RS)-3-propylcyclohexanone (15) to the two tsetse species were comparable (p > 0.05). Blending the two attractants did not lead to any change to both tsetse species (p > 0.05). The study identifies potent attractants and repellants on the two Glossina spp. and therefore lays a useful basis for the development of more effective behavioural control of the tsetse species
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    Adsorbent Materials from Rice Husks and Water Hyacinth Ashes Blended with Bone Char for Removal of Fluoride Ions from Contaminated Water
    (Kenyatta University, 2020-11) Gitonga, Rose Kagwiria
    Safe and readily available water is important for public health, whether it is used for drinking, domestic use, food production or recreational purposes. Consumption of contaminated water may lead to acute and chronic health effects. The most common water pollutants include heavy metals, pesticides, and anions such as fluorides, arsenic, arsenite, chromate and selenate, which cause various diseases such as brain, liver and bone ailments. Among the pollutants, fluoride is the most occurring contaminant in water. Fluoride ions are absorbed by the body mainly through drinking water containing a concentration of more than 1.5 mg/L for a long period of time. At high levels, they cause health problems which range from mild to severe teeth and bone fluorosis. Many methods have been used for removal of anionic contaminants such as fluoride from drinking water. These methods include reverse osmosis, precipitation, electro dialysis and adsorption. Most of these methods are too expensive. This study aimed at synthesizing an adsorbent material from low cost agricultural waste products materials namely water hyacinth ash (WHA) and rice husks ash (RHA) blended with bone char and determine its effectiveness in removal of fluoride ions from contaminated water. Five zeolitic materials were prepared and labelled as zeolitic A (ZA), zeolitic B (ZB), zeolitic C (ZC), black bone char (BBC) and white bone char (WBC) by varying the amounts of rice husks and the water hyacinth ashes and blending with white and black char. Analysis of various oxides contained in the adsorbents was done by X-ray Fluorescence Spectrometer (XRF). Adsorption tests for fluoride ions by the five adsorbents were carried out based on the batch adsorption studies. These include varying the shaking speed, temperature, contact time, initial anion concentration and adsorbent dose. The concentration of fluoride ions remaining in the solution after adsorption was analysed using Fluoride Ion Selective Electrode (FISE). Results for the adsorption capacities for the five adsorbents fitted best onto Freundlich isotherm model which gave adsorption capacity (Kf) values as follows; ZA 1.181, ZB 1.281, ZC 1.061, BBC 1.142, BWC 1.112. The zeolite B had the highest adsorption capacity. This indicates that blending a zeolitic material by black bone char improves its adsorption capacity for fluoride ions from contaminated water. At optimum concentration of fluoride ion and optimum temperature, ZB removes 75.50% and 80.00% of the ion respectively. It gives 75.50% at a shaking speed of 120 rpm and 77.00% at optimum contact time. Therefore it is necessary to optimize use of locally available materials for application in defluoridation of water.
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    Adsorption of Selected Heavy Metals Using Modified Pennisetum Purpureum Plant Stalks: A Case Study of River Ruiru, Kiambu County, Kenya
    (Kenyatta University, 2022) Murage, Daniel; Eric Masika; Alphonse Wanyonyi
    Water pollution is a global problem affecting the welfare of humanity. Availability of clean water is a fundamental prerequisite to public health safety and the survival of the human race as well as animals. However, pollution of river water by heavy metal ions deposition is a grave ecological problem especially in developing countries. Previous research work on analysis of fish, soil sediments and water samples obtained from Nairobi and Ruiru river confirmed the presence of heavy metals. These metal ions which include lead, chromium, and iron are mainly from industrial effluents discharged into the rivers. Presence of the heavy metals in the water, pose a serious health risk particularly to rural populations which rely majorly on the river water for domestic purposes. Several methods for elimination of the heavy metal pollutants from river waters have been previously employed. However, most of these methods have proved to be expensive and cumbersome, hence not sustainable. Simpler methods are, therefore, needed for better sustainability. This research explored the potential of modified Pennisetum purpureum plant adsorbent in eradication of lead (II), manganese (II) and chromium (VI) ions from Ruiru river water by adsorption process. Sampling was done at three different locations along the river, that is, Ruiru Town, Juja Farm and Fourteen Falls. The mean concentration of heavy metal ions was determined before and after the adsorption process in triplicates using Atomic Absorption Spectroscopy (AAS). Effect of changes in pH on adsorption was investigated by conducting adsorption at pH of 5, 7 and 9. Data was organized in excel worksheets before it was transferred into SPSS software for analysis. The results show high chromium and lead pollution of the Ruiru river. Average concentrations of chromium and lead were 1.495±0.09 ppm and 1.610±0.1 ppm respectively. Average Manganese levels were 0.05±0.01 ppm which was within the permissible level (0.5 ppm). Modification of the adsorbent surface improved its adsorption capacity. The modified adsorbent achieved greater % adsorption in all the three metals. Increase in the pH of adsorption from 5 to 9 had a reducing effect on the percent adsorption of metal ions from water samples with significant reductions in % adsorption being recorded for lead and manganese ions but not for chromium ions. These results show the potential of the Pennisetum purpureum plant in the purification and detoxification of river water by adsorption. This adsorbent presents a more readily alternative to many current adsorbents and adsorption methods in use. However further research is needed to ascertain the best set of conditions as well as the most suitable modification treatment for maximum adsorption.
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    Aflatoxin Detection Rate Using Urine Immunoassay and Compliance Level with Control Strategies among Makueni Residents Attending the County Hospital
    (Kenyatta University, 2023-11) Buuri, Kaburia Martin; Michael Gicheru; Joshua Mutiso
    Aflatoxicosis is caused by Aflatoxins. The pathogenic fungi responsible are A. parasiticus and A. flavus that contaminate foods such as maize, rice, groundnuts, sorghum, wheat, millet and cassava among others. Aflatoxins mainly cause health issues that target the liver with fatal consequences. Aflatoxin toxicity range from acute to chronic and disease severity depends on age, diet, nutrition quality, extent of exposure, pre-existing health issues and gender. Preventive strategies are mainly focused on proper pre- and post-harvest food handling especially cereals. Aflatoxicosis is highly prevalent in the eastern region of Kenya despite the existence of preventive measures. The present study was carried out in Makueni County at the County referral hospital, which was selected purposively because it had the highest death rate during the 2004 aflatoxin-poisoning outbreak. The study aimed at establishing the detection level of aflatoxicosis using the Aflatoxin M1 (AFM1) urine immunoassay as well as evaluating the level of compliance to the aflatoxin preventive strategies put in place and challenges associated with control of aflatoxicosis by residents of Makueni County. A cross-sectional design was chosen for the study in which one hundred and six volunteers took part. Data were obtained via questionnaires and urine samples were analyzed for presence of Aflatoxin using Aflatoxin M1 immunoassay. Collected data were entered into an excel worksheet and later analyzed using SPSS version 20 with a P value considered significant at < 0.05. Results showed that 99.1% of study participants had AFM1 in the range of 25-2337 pg./ml, with a mean concentration of 637.6 ± 512.7. Notably, majority (n=82; 77.4%) of the residents knew the negative effects of aflatoxin on their health. Additionally, the sampled residents had a compliance rate of 72.6% (n=77) while 26.4 % were not compliant to mitigation measures put in place to minimize aflatoxin contamination. At the baseline, while 67.9% of the residents indicated that handling of cereals hygienically and using proper means to dry and store their farm produce, 1.9% reported that smoking of cereals was the most effective means to prevent aflatoxin contamination. It was concerning that, 29.2% of the residents did not know which method of cereal handling was the most effective in controling aflatoxins. The study concludes that the present prevalence of aflatoxicosis in Makueni County is high despite high rate of compliance with aflatoxins preventive measures. The study recommends further research to be carried out on better aflatoxins preventive methods and the residents to be educated on proper application of mitigation strategies in order to achieve effective control of aflatoxicosis.
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    Age related mating behaviour and bioassay of the synthetic sex pheromone of the spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae)
    (2012-05-04) Njogu, Florence Njeri
    The influence of age on the mating behaviour of Chilo partellus (Swinhoe) was investigated. The observations on the behaviour of 0-, 1-, and 3-day-old months were carried out to ascertain if any changes occurred relative to age in attractiveness of the females and in the responsiveness of the males. The results showed that males were more attracted to 0-day old females than to 3-day old ones. No difference in attractiveness was found between 0- and 1-day old females. 0-day old males were found to have a significantly lower responsiveness to the females than both 1- and 3-day old ones. However, although 3-day old males were more responsive than 1-day old ones, this difference was not found to be significant. Observations of the mating behaviour of the moths showed that there were quantitative differences in the behaviour of 0-day old males and 3-day old ones. 0-day old males were found to spend the largest proportion of the time passive and only very few of them copulated by the end of the observation period. On the other hand, 3-day old males spent a relatively smaller proportion of the time passive and most of them had mated by the end of the observation period. No significant differences were detected between the behaviour of the laboratory reared and the field collected insects. The effect of proximity of release points of the two pheromone components (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol of the female moth were investigated. Separating the dispensers of the two components by a mere 3 cm resulted in a significant change in the male behaviour and a decrease in the bait performance as compared to the dispensers with the two components dispensed close to each other. A study to establish the effect of polyvinyl chloride (PVC) on the response of the male C. partellus to the synthetic blend of the sex pheromone of the female showed that PVC does not inhibit male response to the pheromone. It was found, however, that the PVC dispenser loaded with the alcohol was inferior in its performance to the filter paper dispenser loaded with the same and this could possibly be attributed to a lower release rate of the alcohol by PVC.
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    Agrobacterium mediated transformation of selected maize inbred lines with ppzp200 towards enhancment of lysine and methionine content
    (2012-03-26) Limbua, Purity Gacheri; Machuka, Jesse; Ombori, O.
    Maize (Zea mays (L.) is one of the most important cereals used both for human and animal consumption in the world. Despite its importance, maize is not a suitable single source of nutrition because it does not provide the essential amino acids lysine and methionine in sufficient quantities to meet the nutritional needs of humans and other animals. Lysine is a necessary building block for protein in the body while methionine is the body's primary source of sulphur. Strategies to improve the nutritional quality of maize for high lysine and methionine have involved both genetic engineering (GE) and non-genetic engineering approaches such as marker assisted selection. Breeding is however laborious, lengthy and carries along undesired alleles. The objective of this work was to manipulate maize inbred lines towards enhancement of lysine and methionine content in the endosperms through Agrobacterium mediated transformation. Maize kernels mainly store proteins as a, {3, y and 0 zeins. The immature embryos of three tropical maize inbred lines (TL IS, CML216 and CMLI44) and a temperate line (AlSS) were transformed using Agrobacterium tumejaciens strain EHAI01 carrying an expression cassette designed to upregulate the Z I 0 protein for methionine enhancement as well as down-regulate the a. zein storage protein by RNAi. The T -DNA also contained P-zp22/6 as the promoter and the phosphinothricin acetyltransfarase gene (bar) used for selection of transformed tissue. Putative transformants were tested for presence of the transgene by PCR designed to amplify the P-zp22/6 promoter sequence. Calli survival frequencies were calculated as a percentage number of surviving calli in relation to the total number of embryos infected. These ranged from 2.S9 % forTLIS to 9.11 % for AISS. This data did not detect any significant difference (p>0.05) among the genotypes on the percentage of calli which survived. Transformation efficiency was calculated as a percentage of the number of PCR positive plants divided by the total number of embryos infected. This ranged from 0% for TLIS to I.S3% for AISS. The data suggest the possibility of manipulating storage proteins and regenerating normal transgenic maize with normal kernels. Further work should involve gene expression assays for accumulation of {3, y and 0 prolamins in the kernels and southern blot analysis to confirm stable integration and the copy numbers ofPzp22/6 gene in the PCR positive plants.
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    Agrobacterium tumefaciens mediated transformation of Sudan maize genotypes using NPKI gene for enhancing drought stress tolerance
    (2011-11-29) Abdalla, Rasha Adam Omer; Jesse Machuka; Abdelbagi M. Ali
    Drought is one of the most important abiotic factor affecting maize production worldwide. Agrobacterium-mediated gene transfer technique has been established as a versatile way of improving important crops for tolerance to biotic and abiotic factors. Through this technique, the drought tolerance gene, NPKI, has been used in the transformation of temperate maize after its isolation and characterization from tobacco. Recovered transgenic events were observed to have enhanced tolerance to water stress. The accelerated adoption of the transformation technique in Africa, and indeed in Sudan, will depend on the ease with which transgenes of agronomic importance can be integrated into appropriate germplasms. This study aimed at screening important Sudanese maize inbred lines and open pollinated varieties (OPVs) for transformability via the integration of the NPKI gene. Eight inbred lines and three OPVs were evaluated. A188 was used as the standard inbred line check while KAT was used as the local OPV check. Freshly isolated immature embryos of maize were inoculated with Agrobacterium strain EHA101 harbouring the plasmid pSHX004 in LS infection media for 5 minutes and then co-cultivated on LS cocultivation media for 3 days. Embryos were then transferred to selection media supplemented with 250mg/l cefotaxime and 1.5mg/L bialaphos. After two weeks on this media, calli were subcultured on selection media containing 3.0 mg/L bialaphos for 4 weeks. Bialaphos resistant callus events were then transferred to maturation media supplemented 3mg/L bialaphos for 2 weeks before transferring to shooting media. Shoots were then transferred to rooting media. Plantlets with well-formed root system were transferred from the in vitro environment to green house for hardening. Hardened plantlets were transplanted to soil in the greenhouse and maintained till they set seeds. To confirm the presence of the transgene, PCR analysis was done on putative transgenic plants using the Bar primers. Out of a total of 4401 immature embryos from the 13 genotypes infected, 327 survived selection in bialaphos. Bialaphos resistant calli emerged 3-4 weeks after selection. IL3, IL15, Hudiba-2, IL1, IL38, Hudiba-1, A188 and KAT produced compact calli from their scutella surfaces while IL28, IL42, IL43, Mojtamaa-45 and IL16 established watery nonembryogenic calli. Statistically significant differences (p<0.05) were observed between the genotypes with respect to transformation frequency (TF). IL3 was identified as the most amenable to transformation with a TF of 31.7% and proved to be superior to A188, which recorded a TF of 5.82%. Hudiba-2 was identified as the most transformable OPV with a TF of 8.7% compared to that of 7.3% for KAT. ILI and Mojatamaa-45 proved to be poor responders to transformation with TFs of 2.5% and 1.7%, respectively. Putative transgenics were recovered from IL3, IL 15, Hudiba-2, ILI, IL38, Mojatamaa-45, A188 and KAT. The frequency of regeneration of bialaphos resistant shoots varied from 6.9% for IL38 to 100% for Mojtamaa-45. PCR analysis indicated a 540bp fragment in the DNA extracts from transgenic R, plants. Transformation efficiency (TE) was found to depend on the genotype used. The highest TE was observed for IL3 (3.7%), while the lowest TE of 0.0% was observed in IL42 IL43, IL16 and 11,28. Various abnormalities were observed in putative transformants including dwarfism, tussel seed and lack of ear. However, plants grew to maturity and were able to establish seeds in spite of these abnormalities. In conclusion, the inbred line IL3 and the OPV Hudiba-2 proved to be the most amenable Sudanese genotypes to A. tumefaciens-mediated transformation. Future research in maize improvement through biotechnologies such as tissue culture and genetic transformation should be focussed on these good responders.