Faculty of Applied Science and Technology

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    Decision quality: the impact of process redesign as an intangible, benefit on information technology investment decisions
    (2001) Atieno, Anne Ndede
    IT investment decisions often focus on tangible costs and benefits such as technical, strategic, and financial issues. Less tangible benefits such as process redesign integration, bave been largely ignored. Decisions makers who rely solely on these tangible costs and benefits for their assessment of IT investment value without integrating intangible benefit consideration may be making sub-optimal decisions and investments. This study looked at rhe important, yet often overlooked, intangible benefits consideration in the IT investment decision process with particular focus on process redesign as an intangible benefit. Survey questionnaires were sent out to a sample of 949 firms in three industries: healthcare, chemical, and insurance to solicit information from the chief information officer (CIo) on the level at which they integrate process redesign consideration in the IT inr-eshnent decision. Several important findings resulted from this research effort. First, the study irm"nr;fied seven component factors of process redesign and used these factors to measure the M of process redesign integration into the IT investment decision. Second, the study mfirmed, empirically, that there was an association between the consideration of tangible and intangible benefits. Those firms that expend large effort or resources towards tangible benef,rts consideration also spend more effort or resources toward intangible benefits consideration than otherwise. Third, it was empiricaliy determined that certain process redesign benefit factors received greater consideration than others. Fourth, it was determined #mr decision makers considered tangible benefits to be more important than intangible hmefits consideration and expended a greater portion of effort or resources towards the mideration of the former. Finally, this study found that the strategic relevance of IT in an orgAnization was associated with the level of effort or resoulce deployment towards inrangible benefits. Additional areas for further research were also identified.
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    The nonnegative P 0 -matrix completion problem.
    (2003) Choi, Ji Young; Dealba, Luz Maria; Hogben, Leslie; Kivunge, Benard M; Nordstrom, Sandra K; Shedenhelm, Mike
    In this paperthe nonnegative P 0 -matrix completion problem is considered. It is shown that a pattern for 4 × 4 matrices that includes all diagonal positions has nonnegative P 0 - completion if and only if its digraph is complete when it has a 4-cycle. It is also shown that any positionally symmetric pattern that includes all diagonal positions and whose graph is an n -cycle has nonnegative P 0 -completion if and only if n =4.
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    Subloops of sedenions
    (2004) Kivunge, Benard M; Smith, Jonathan D. H
    This note investigates sedenion multiplication from the st andpoint of loop the- ory. New two-sided loops are obtained within the version of t he sedenions introduced by the second author. Conditions are given for the satisfactio n of standard loop-theoretical identities within these loops.
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    SEARCH FOR BIOLOGICALLY ACTIVE SUBSTANCES FROM OKINAWA MARINE ORGANISMS -ISOLATION AND STRUCTURES OF THE COMPOUNDS WHICH INHIBIT THE DIVISION OF THE FERTILIZED SEA URCHIN EGGS
    (2005-09) NOSE, HOLLlNESS MANYAMA
    Ethyl acetate extracts of 75 Okinawa marine organisms were screened by the fertilized sea urchin egg assay. Among them 51 specimens showed potent cytotoxity and 20 specimens exhibited moderate activity. The constituents of five marine organisms (three sponges, one soft coral and one alga) whose ethyl acetate extract displayed strong inhibition of various cleavages of fe11ilized sea urchin eggs were examined. Bioassay guided fractionation of these extracts led to the isolation of twelve compounds of which eight (1, 2, 3A, 3B, 4A, 4B, 5 and 6) were new. The structures were established by 1D and 2D NMR spectroscopy and mass spectroscopy. Compounds 1 and 2 inhibited the first cleavage of the fertilized sea urchin eggs at 1 ppm. Compounds 3A, 3B, 4A, 4B and 8 inhibited the development of the fertilized sea urchin eggs at the blastula stage.
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    On the cycle indices of frobenious groups
    (2010) Munywoki, Michael; Kamuti, Ireri; Kivunge, Benard
    There are several very useful formulas, which give the cycle indices of the binary operation of the sum, product, composition and po wer group of M and H in terms of cycle indices of M and H . One very useful binary operation on groups, which has not been exploited, is the semidirect product. Suppose G = M ⋊ H , a semi direct product; the question is: how can we express the cycle index of G in terms of the cycle indices of M and H ? This work partially answers this question by considering the cycle indices of so me particularly semidirect product groups; namely – Frobenious groups
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    LIMITATIONS IN THE CONVECTIONAL ISBN - 10 CODE
    (2012) Kamaku, Waweru; Mwathi, Cecilia; Kivunge, Bernard
    The I nternational S tandard B ook N umber system (ISBN - 10) which was in operation until 2007 uniquely identified every book published internationally but was later replaced with the ISBN - 13 . The code was had the ability to detect and correct single errors, to detect and correct some transposition errors and also d etect multiple errors. This paper discusses some major limitations in the code and shows how error detection and correction capabilities affected the total dictionary on the code. The paper then shows the great need that lead to the development of the ISBN
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    Magnetohydrodynamic (MHD) Free Convective Flow past an Infinite Vertical Porous Plate with Joule Heating
    (2013) Sigey, K. Johana; Okelo, A. Jeconia; Gatheri, K. Francis; Ngesa, O. Joel
    This work addresses the problem of Magnetohydrodynamic laminar unsteady flow of an incompressible electrically conducting fluid past an infinite vertical porous plate. It investigates how joule heating affects the velocity and temperature profiles of the fluid flow subjected to transverse magnetic field. The research examines specific equations of MHD flow which are solved numerically by finite difference approximations, using computer programme. The numerical results of this study reveal that an increase in joules heating parameter causes an increase in the velocity and temperature profiles uniformly near the plate but remain constantly distributed away from the plate, implying that the flow field of the MHD free convective flow is influenced substantially by the strength of Joules heating near the wall of the plate and at the mainstream
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    SIMULATED MODELING: CONTRASTING Ca/Mg AND Mn+-NATURAL ORGANIC MATTER COMPETITIVE COMPLEXATION IN WATER
    (2015-07-20) Mbugua, John
    Complexing capacities of calcium and magnesium with natural organic matter (NOM)/selected organic chelating agents, in the presence and absence of other major and trace cations in water, were studied by anodic and cathodic square wave stripping voltammetry techniques (ASWSV and CSWSV). Under predetermined and optimized physico-chemical parameters (pH, temperature and ionic strength), calcium-NOM complexation and competitive complexation by other elements of known concentration (Pb, Zn, and Cu) were determined. Voltammetric measurements showed competition between calcium and the other cations for the binding sites of humic substances at depositing, measuring and equilibrating potential of -2V and +1V and scan time of 150seconds. Two systems were complexed by known concentrations of NOM fractions (Humic acid (HA), 1, 2-dihydroxybenzene (CAT/catechol) and tannic acid (TA)): Mn+-NOM; Mn+ Calcium-NOM complexes at different pH conditions. Results show significant differences in peak currents in the order Mn+> Ca/Mn+-TA/HA/CAT > Mn2+ TA/HA/CAT but differed depending on the metal species, type of humic chelant and pH. Visual Minteq and PHREEQC simulations show differences in distribution of scale causing species such as Ca2+, CaOH+, Mg2+ and MgOH+ that are highly dependent on the pH and concentration. This paper presents results of part of the work aimed at providing simulated modeling alternatives in combating scaling as a consequence of cooling water used in industry. It equally provides an assurance on the re-use of the scarce water resources by simulated water experiments and models
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    SOCIO-DEMOGRAPHIC AND PROGRAMMATIC CORRELATES OF SUSTAINABLE HIV-PROTECTIVE BEHAVIOURS AMONG ADOLESCENT GIRLS AND YOUNG WOMEN AGED 15-24 YEARS RESIDING IN MUKURU SLUMS IN NAIROBI
    (2019-06) NGUKU, JULIUS NJATHI
    The high incidence of HIV infections among slum-dwelling adolescent girls and young women (AGYW) has been attributed to the numerous and often layered vulnerabilities that they encounter, including unfavourable power relations that are worsened by age-disparate sexual relations, limited access to sexual and reproductive health information; and violence against women. Despite the large and immediate HIV prevention need of young women, there is a dearth of information on which factors are associated with practice of sustainable HIV protective behaviours; and the programme models that are most efficacious for eliciting the behaviours in the sUb-population. The purpose of the study was to determine social demographic and programmatic correlates of sustainable HIV-protective behaviours among adolescent girls and young \vomen aged 15-24 years residing in Mukuru Slums in Nairobi. This was done by assessing HIV protective behaviours practiced by the participants who had benefited from three different HIV prevention programme models at least one year before. This research contributes to the realization of the Kenya AIDS Strategic Framework (KASF) 2014/152018119 which guides Kenya's response to the HIV epidemic. In this retrospective COhOl1 study, purposive sampling was used to select the three programmes and probability proportionate to size sampling was used to select the young women from among previous beneficiaries of the programmes. A total of 423 respondents rarticred in the stUdJ inciUdin~ 207 rTVi?mllrrni1~ij 1 1 rr ·r~11 ~~m rm
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    THE ROLE OF COENZYME-QlO IN THE REGULATION OF ThTFLAMMATORY IMMUNE RESPONSES DURING EXPERIMENTAL CEREBRAL MALARIA IN MICE
    (TUK, 2019-06) NYARIKI, JAMES NYABUGA
    Cerebral Malaria (CM) is a form of malaria that causes a complex neurological syndrome, whose ~ology is mediated by severe inflammatory processes triggered by the immune system of the : 5t following infection with Plasmodium Jalciparum. There is limited progress in the -. development of new approaches for the treatment of CM. The aim of this study was to -~-:ematically elucidate the putative impact of oral administration of Coenzyme-QlO (CO-QIO) on ~ initiation or regulation of inflammatory immune response in experimental cerebral malaria \1). In addition, the ability of CO-Q lO to assuage ECM-induced inflammation and oxidative _ss was detennined. For this purpose, one group of C57BLl6J mice was used as control; the _::lnd group was infected with Plasmodium berghei ANKA (PbA) and the third group of mice -. orally supplemented with 200mglkg CO-Q IO and then infected with PbA. Within this -:--erimental set up, a series of experiments were carried out in concert with the study objectives. _... included: survival analysis, extensive clinical and biochemical analyses, flow cytometry, rime PCR for mRNA levels, immunoblot and immune-based assays. It was observed that __dministration of CO-QlO both before and after PbA infection protected majority of mice --J ECM. Importantly, CO-QIO supplementation significantly hampered infiltration of -lmatory monocytes, T cells and cytotoxic granzyme B into the brain. Brain tissue analysis ed a reduction in the expression levels of inflammatory transcripts TNF -u and MIP-l ~ in administered mice. Furthermore, CO-QlO administration resulted in decreased expression -~okines (CXCL9, CXCL 10) in the brain, leading to reduced levels of activated pathogenic _ -with concomitant improvement in blood brain barrier disruption. In addition, CO-QIO __ 91ed the differentiation and maturation of both splenic and brain dendritic cells during '\otably, anti-inflammatory cytokines IL-IO and IL-22 together with T-regulatory celis, -are associated with protection during ECM, were up-regulated in CO-QlO treated mice. -. ably, Co-QJO was very effective in decreasing NF-KB phosphorylation, which is _ -:-00 with ECM pathology. Splenic analysis of innate lymphoid class two (ILC2), which -.ll to playa protective role during ECM, showed augmentation in the spleens of CO-QIO . . ered mice. Meanwhile, levels of matrix metalloproteinases-9 and angiopoietin-l&2, :!..."'e linked to severity of CM were reduced in mice administered with CO-QIO. '----~~. . e. CO-Q IO supplementation abrogated malondialdehyde, diene and 8-hydroxy:'::::::trr:--2 osine \8-0HDG( which are markers of oxidative stress and DNA damall>e. Moreover,
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    PESTICIDES: OCCUPATIONAL EXPOSURE AND POTENTIAL IMPACTS ON ECOSYSTEM AND HUMAN HEALTH IN MERU COUNTY, KENYA
    (Technical University of Kenya, 2021-03) MARETE, GABRIEL MUTHEE
    ABSTRACT This study assessed the usage of pesticides and its impacts on ecosystems and human health through occupational exposure in selected farming communities in Imenti North, Imenti South and Buuri Sub-counties in Meru, Kenya, where horticultural crops including French beans, kales and tomatoes are grown intensively for export and local consumption. The study was done through use of questionnaire distributed to farmers, agricultural extension and health care workers in selected farms in the three Sub-counties. In addition, analysis of pesticide residues by GC-MS in samples of farm soil, French beans, kales and tomatoes, from randomly selected sites in the three Sub-counties was done. The survey established that various pesticides in the classes of organochlorines, organophosphates, carbamates, pyrethroids and fungicides, were used in the three Sub-counties, with the most frequently used ones (>60 respondents out of 173) being parathion, diazinon, permethrin, pirimiphos methyl, carbaryl, deltamethrin, dieldrin, methoxychlor, cypermethrin, propoxur and carbofuran. Some of these including dieldrin, parathion and carbofuran were used illegally because they have been banned. Although most farmers had general information on pesticide usage through various social groups and contact with agricultural extension workers, only 32–43 % of the farmers had received training on pesticide handling and use. Most farmers (65%) had knowledge of safe pesticide handling procedures including reading labels on packages and wearing protective clothing; but many farmers (44% in Buuri, 57% in Imenti South and 60% in Imenti North) did not wear the requisite protective clothing when applying pesticides. Agricultural extension workers (52%) and health care workers (59%) were trained in their work and had at least a certificate level qualification from a tertiary institution. Most agricultural extension workers (95%) and health care workers (71%) had experience of dealing with pesticides and knew how to administer 1st AID against pesticide poisoning, respectively. Farmers (26%) reported experiencing health effects after using pesticides, with most effects being felt after using dimethoate, malathion, carbofuran, carbaryl and heptachlor. There was a statistically significant (p < 0.05) association between various factors (availability of protective clothing, hiring of labourers, farm land size, expenditure on pesticides and expenditure on treatment, respectively) on intoxication from pesticide exposure. Analysis of organochlorine pesticide residues in soil, French beans, Kales and tomatoes sampled randomly from the selected sites found widespread contamination of soils with organochlorine pesticide residues, with total (Σall OCs analysed, in μg/Kg dry weight) ranging from 15.78 – 307.70 in Imenti North, 1.25 – 159.88 μg/Kg in Imenti South, and 14.96 – 106.13 μg/Kg in Buuri. However, organochlorine pesticide residues were not detected in any of the vegetables. Other pesticides, including chlorpyrifos, carbendazine, imidacloprid, acetaprimid, metalaxyl, diazinon, azoxystribin, triadimefon, acephate, thiamethoxim and diuron were found in farm soils, French beans, kales and tomatoes, with concentrations (in μg/Kg dry weight) in soil samples ranging from BDL (metalaxyl and azoxystrobin) – 13,030 (carbendazin). In French beans, kales and tomatoes, the concentrations (in μg/Kg wet weight) ranged from BDL – 290, with the highest being imidacloprid in tomatoes. The pesticide residue levels generally were very low and met the Maximum Residue Limits set by European Union and other countries, and posed no concern to human health. Risk assessment of the residues in terms of estimated daily intakes (mg/Kg BW/day) also confirmed no health risk in the population. However, it is recommended that preharvest intervals for the pesticides should be observed in the three Sub-counties to avoid long term exposure to consumers.
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    ISOLATION AND CHARACTERIZATION OF LACTOBACILLUS AND WEISSELLA STRAINS FROM KIMERE TOWARDS DEVELOPMENT OF A NOVEL PROBIOTIC YOGHURT FOR AFLATOXIN B1 CONTROL
    (Technical University of Kenya, 2022-01) NDUTI, NICHOLAS NDARU
    In Kenya, maize is an important staple food. Unfortunately, household maize is generally spoilt by fungi whose mycotoxin metabolites have been found to cause adverse effect to animal and human health. The study had four objectives: i) to determine aflatoxin levels in maize and maize flours in three different selected regions in Kenya. ii) To isolate and characterize Lactobacillus and Weissella strains in Kimere and determine their individual strain capacity to sequester aflatoxins. iii) To assess growth of the isolated Lactobacillus and Weissella strains in milk so as to develop a novel yoghurt using the highest Lactobacillus and Weissella aflatoxins binding strains. iv) To determine the capacity to lower aflatoxin B1 (AFB1) metabolite (aflatoxin M1) in urine of children from Eastern Kenya by Lactobacillus and Weissella isolated strains. To achieve the objectives, 75 maize grains and 27 flour samples were collected from three parts of Kenya and analysed for aflatoxins by Enzyme linked immunosorbent assay (ELISA) plus spectrophotometric technique. Basic and advanced molecular microbiology techniques were employed to obtain Lactobacillus and Weissella isolates from Kimere. These included growing the Lactobacillus and Weissella in a selective media followed by Gram staining. To identify the species of the isolated Lactobacillus and Weissella, Polymerase Chain Reaction (PCR) was used to amplify the DNA extracts. DNA blocks were sequenced and identified using the Blast software process. A novel yoghurt was developed using an isolate of Lactobacillus rhamnosus and Weissella, along with starter culture Streptococcus thermophilus. The capacity of the isolates to sequester or bind AFB1, in vitro and in vivo was determined using ELISA. Where applicable High Performance Liquid Chromatography (HPLC) as well as Spectrophotometric techniques were used. Sequestration of AFB1 in vivo was examined indirectly by measuring aflatoxin M1 (AFM1) in urine of school children in Eastern Kenya whose diet was mainly maize or maize-based. Samples of urine from children were analyzed by ELISA, and Liquid chromatography-mass spectrophotometry combination (LC-MS). The results for objective one showed a significant difference between the AFB1 levels in Maize grains (P<0.05) from different regions. Maize samples from Eastern Kenya region had the highest contamination. Maize samples from Nairobi had the lowest concentration at 6.02±0.31145 ppb. There was no significant difference in the total aflatoxins in Maize flour samples from all regions (P>0.05). Moreover there was significant difference in AFB1 concentrations between stores for example from Western and Eastern regions (P<0.05). Total aflatoxin levels in maize flours were slightly above international standard of 5ppb but lower than the Kenyan standard which is 10 ppb. The results for objective two indicated that out of 300 isolates from Kimere that were analysed for capacity to lower the risk of aflatoxin exposure in vivo or in vitro, Weissella cibaria NN20 had highest but statistically insignificant survival in low acidic condition than probiotic Lactobacillus rhamnosus GR-1 and Escherichia coli GR12 (P>0.05). Weissella cibaria NN20 bound 43.7±2.3 % of total available AFB1 in modulated media. Objective three and four had results showing that lactobacillus isolated from Kimere had capacity to ferment milk same as yoghurt and be able to reduce aflatoxin M1 in urine in vivo from 6.3ppb to 2.6ppb. The results confirmed the hypothesis that consumers were at a risk of aflatoxin exposure and that they were indeed consuming the AFB1 contaminated maize and maize products. In conclusion, the findings confirmed relatively high concentrations of Aflatoxins in maize and maize flours despite government efforts to prevent this. These results call for further intervention at table level. The Lactobacillus and Weissella isolates reduced AFB1 both in vitro and in vivo, suggesting that probiotic yoghurt has the potential to prevent aflatoxicosis among consumers of maize and maize based diets.
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    OUTCOME OF CHRONIC SCHISTOSOMIASIS IN REGULATION OF MALARIA DISEASE SEVERITY AND PATHOLOGICAL EVENTS IN A MOUSE MODEL
    (Technical University of Kenya, 2022-05-01) MUGANDA, ANDREW
    First, I wish to thank the Almighty God for the strength, good health, and focus for making this journey possible. Special thanks to my supervisors Dr. Edward Okonjo, Dr. James Nyabuga and Prof. Dorcas Yole, for the excellent supervision, commitment and guidance throughout the development of this thesis. I extend my gratitude to my supervisors for helping in conceptualization of the idea and putting it together. Furthermore, for walking with me throughout the research journey. In addition, my supervisors were very committed in ensuring that I overcome my challenges during experimental stages and helping me understand that drawbacks are avenues for learning. I am grateful to the staff at the Department of Applied and Technical Biology and Department of Biochemistry and Biotechnology at TU-K for the assistance during my laboratory sessions and I appreciate them for providing me with the necessary academic support that enabled me to finish my studies. Special thanks to the Muganda’s family, may God bless you abundantly for walking with me and encouraging me to focus on the finish line.
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    THE ROLE OF KHAT IN EXACERBATING MANGANESE-INDUCED DELETERIOUS EFFECTS AND PUTATIVE RESCUE BY COENZYME-Q10 IN A MOUSE MODEL
    (Technical University of Kenya, 2022-06) WEKESA, KENNEDY CHEPUKOSI
    ABSTRACT Khat, a plant containing phytochemicals that act as psychostimulants is widely grown and used in Kenya and East Africa. It contains amphetamine-like chemicals, cathine and cathinone, largely responsible for hematotoxicity and organ damage. There is growing use of this herb in rural and urban areas heavily polluted with environmental toxicants. Limited research has been done on khat toxicity, more so, on how to counter it. In addition, there is limited information on the biochemical, physiological and neurological changes due to co-exposure to khat and the other metal toxicants commonly present in polluted environments, such as manganese. This study was conducted to elucidate the toxicological profile of khat with or without manganese and the putative ability of coenzyme-Q10 (CoQ10) to modulate negative physiological and biochemical processes due to khat and manganese-induced toxicities. This laboratory-based research involved the use of a well characterized mouse model in which the groups of Swiss albino mice were either treated with khat or manganese or CoQ10 or the three treatments combined. Group one was the control group that was not given any of the treatments; group two was supplemented with CoQ10 (200mg/kg b/w); group three was given khat extract (1500mg/kg b/w); group four had free access to water dissolved in manganese ad libitum (4g/L); group five was co-treated with CoQ10 (200mg/kg b/w) and khat (1500mg/kg b/w); group six was given CoQ10 (200mg/kg b/w) and had free access to manganese in water (4g/L); group seven was given khat (1500mg/kg b/w) and had free access to manganese dissolved in water (4g/L b/w), lastly, group eight was treated with CoQ10 (200mg/kg b/w) and khat (1500mg/kg b/w) and had free access to manganese in water ad libitum (4g/L). The study was conducted in two phases to simulate subchronic (90 days) and chronic (132 days) exposure to khat. A series of experiments were performed according to the study objectives. They included: monthly body weight measurements and rapid murine and behavioral score (RMCBS), biochemical assay for liver and kidney biomarkers, reduced glutathione (GSH) assay for oxidative damage, cytokine assay for changes in immune response and histology for organ pathology. Subchronic and chronic exposure to khat induced hematological perturbations leading to anemia that were nullified in the presence of CoQ10. During the subchronic phase, khat caused neurological disturbance that was exacerbated on exposure to manganese (khat+Mn++). However, CoQ10 appeared to restore the khat and manganese-induced neurological dysfunctions. Additionally, there was severe hepatotoxicity and nephrotoxicity following simultaneous exposure to khat and manganese as depicted by the elevated liver (AST, ALT, GGT, total bilirubin) and kidney (creatinine) biomarkers. Notably, supplementation with CoQ10 attenuated khat and/or manganese-induced hepatotoxicity and nephrotoxicity. Exposure to khat for 90 days and 132 days resulted in oxidative damage in the brain, liver and kidney as depicted by the significant GSH elevation. Nonetheless, supplementation with CoQ10 nullified the oxidative damage. Further findings revealed that, in the presence of manganese, the oxidative damage was enhanced; with CoQ10 suppressing the heightened oxidative damage. Lastly, subchronic and chronic exposure to khat caused inflammation which was enhanced in the presence of manganese as exhibited by the increased levels of the pro-inflammatory cytokines (TNF-α and IFN-γ). Notably, CoQ10 modulated khat and/or manganese driven proliferation of inflammatory cytokines. The results in the current study demonstrate that khat negatively affects vital physiological and biochemical processes and induces multiple organ damage and affects the immune system. Moreover, and for the first time, the results show that chronic exposure to manganese exacerbated multiple forms of toxicities following co-exposure with khat. Additionally, the outcomes demonstrate that CoQ10 may be considered as an appropriate pharmacological mitigation against khat-driven toxicity.
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    APPLICATION OF STRUCTURAL BIOINFORMATICS IN AFRICAN SWINE FEVER VIRUS ANTIVIRAL DEVELOPMENT
    (Technical University of Kenya, 2022-07) KINYANYI, DICKSON BENNET
    African swine fever (ASF) is a fatal hemorrhagic disease of domesticated pigs that is caused by the African swine fever virus (ASFV). This disease poses a threat to food security thus leading to economic losses. Presently, there are no reports of approved available vaccines for ASF. Despite the ASFV sequences having well-conserved promoter motifs, no protein with features able to bind onto the promoter TATA-like elements has been identified, nor an antiviral capable of targeting viral TATA-like elements involved in ASFV transcription. This study aimed at finding a TATA Binding Protein (TBP) and potential minor groove binders (MGBs) that can target conserved promoter motifs in ASFV. The study implemented sequence-based search methods followed by three-dimensional structure modeling. The posterior probability of fold family classification was calculated using TM-fold, and biological function was determined using TM-site, RaptorXBinding Site, Gene Ontology, and TM-align. Subsequently, congocidine congeners, Hoechst 33258, and tris-benzimidazole were selected as potential minor groove binders targeting synthetic DNA constructs containing TATA-like motifs mimicking conserved ASFV promoters. The binding scores and calculated binding energies of docked DNA-ligands complexes were evaluated. The ligand behaviour within the minor grooves was assessed using molecular dynamics (MD) simulation. The results of this study established that the three-dimensional structure of a previously uncharacterized protein pB263R had features similar to a TBP with a TM-score of 0.52, with  95% posterior probability. Additionally, the selected minor groove binders were able to significantly dock on the AT-rich regions of the synthetic DNA constructs containing TATA-like motifs. Further, calculated binding energies revealed that less cytotoxic congocidine congeners and tris-benzimidazole were an improvement of cytotoxic congocidine. The MD simulation and molecular trajectory visualization revealed that the ligands remained embedded in the minor grooves of synthetic DNA constructs during the MD simulation time course. The findings of this study suggest that these ligands may be used as potential antivirals for ASF infection in abrogating ASFV transcription. Critical for control of several ASFV genotypes.
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    FEASIBILITY STUDY FOR YELLOW OLEANDER BIODIESEL PRODUCTION USING EGGSHELL-DERIVED NANOCATALYST SYNTHESIZED BY BOTTOM-UP TECHNIQUE
    (Technical University of Kenya, 2023-10) MASIME, JEREMIAH ODHEK
    The global energy demand is expected to rise by 53% by 2030, depleting crude oil reserves by 2052. This increase in energy demand growth has led to increased CO2 emissions, environmental degradation, and the need for alternative fuels. Researchers are exploring biofuel production using Yellow Oleander seeds, a non-edible plant with high oil content. Heterogeneous base catalysts are preferred for biodiesel production due to their non-toxic, high surface area, reusable, and superior stability, while nanocatalysis increases catalytic activity. The eggshell-derived nanocatalyst was prepared using the bottom-up technique and characterized using TG/DTG/DSC, BET/BJH, XRD, FTIR, XRF, TEM, SEM, and EDX. Response surface methodology was used to optimize biodiesel production from yellow oleander by analyzing physicochemical properties, performance, combustion, and emission characteristics in a 4-stroke engine and life cycle analysis. Yellow oleander oil yielded 64.53 ± 0.53 % under optimal conditions, including 80°C temperature, a petroleum ether solvent, 180 minutes, oilseed particle size, and 1:6 solid-to-solvent ratio, following second-order kinetics. The activation energy, enthalpy of extraction, and entropy were ΔEa = + 33.03 kJ/mol, ΔH = + 38.27 kJ kg-1, and ΔS = + 0.097 kJ/mol.K, respectively. The Gibbs free energy decreases at high temperatures, causing the extraction process to become spontaneous. Using XRD diffractograms, the particle size was determined to be 13.86 ± 0.987 nm. The spherical nature of the nanocatalyst particles was revealed by the SEM and TEM images. From BET analysis, the surface area, average pore diameter, and pore volume were; 5.54 ± 0.48 m2g-1, 18.57 ± 2.16 nm, and ≈ 0.016 ± 0.0 to 0.017 ± 0.0 cm g-1, respectively. The eggshell-derived nanocatalyst, a mesoporous material with a large specific surface area, was found to be beneficial for the transesterification reaction process. The response surface methodology yielded 93.70% of yellow oleander biodiesel under optimal conditions, including a reaction time of 40 minutes, a mild temperature of 60°C, and a 3.68 wt% catalyst loading. The FTIR spectrum of yellow oleander oil and biodiesel showed consistent carboxylate regions. The oil and biodiesel's physical and chemical properties align with ASTM D6751 standards. Engine performance, combustion, and emission behavior were evaluated. B20 was found to be the blend with properties close to that of petrodiesel. The study assessed the production costs and energy balance of a biodiesel plant, revealing an energy balance of 6.94 and an estimated production cost of KES 99.90/L (US$ 0.68)/L). The market price for a biodiesel blend of yellow oleander with 20% biodiesel (B20) was 186.75 KES/L (US$ 1.27 /L). This study synthesized a cost-effective, long-lasting nanocatalyst using waste egg shells to produce yellow oleander biodiesel, which meets ASTM D 6751 specifications and can be used in diesel engines.
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    A MULTI-WAVELENGTH STUDY OF MASSIVE STAR FORMING REGION G188.95+0.89 IN PROBING THE DYNAMICS OF MASSIVE STAR FORMATION
    (Technical University of Kenya, 2023-11) MARTIN MULE MUTIE, MARTIN MULE
    ABSTRACT Massive stars are born in regions that are opaque to optical observations. This is a challenge in understanding the processes that involve their formation. In order to investigate their formations, a multi-wavelength approach in the infrared (IR) to radio wavelengths was employed to probe the environment around the core, where they are formed. To understand the dynamics of massive star formation, we probed the molecular cloud to check the chemical composition, bipolar outflows and detailed measurements of molecular velocity fields. G188.95+089 is the Massive Star Forming Region (MSFR) that was used in our study. The choice of the star-forming region was due to the fact that it is nearby, emits periodic masers and harbours multiple star-forming cores. While there are many tracers that can be utilized to infer the presence of massive star formation, we relied on Class II methanol masers at 6.7 GHz. In executing the multi-wavelength investigation, radio data from the 26 m Hartebeesthoek Radio Astronomy Observatory (HartRAO) dish was used to analyse the observed spectra of 6.7 GHz methanol masers. Interferometric data from the Atacama Large Millimeter/sub-Millimeter Array (ALMA) were used to check molecular line and continuum emissions of the source. Complementary infrared data from WISE, 2MASS, Hi-GAL, GLIMPSE, IRAS and MSX was used to probe the presence of extended sources surrounding the massive star forming region. Results from radio observations showed that the source had five velocity maser features that exhibited average periodicity of 397.6 days and at least two showed evidence of velocity drifts ranging from −2.38 × 10−5kms−1d−1 to +1.88 × 10−5kms−1d−1. One maser feature at 11.45 Km s−1 exhibited a varying spectra with exponential decay as from year 2003 to present. The spectra of the other maser velocity features have varied significantly since detection in 1991. Using ALMA band 6 at ∼ 1.3 mm and band 7 at ∼ 0.93 mm data, we were able to identify eight continuum cores (MM1-MM8) in the source, with masses ranging from 0.40 to 8.20 solar masses. In the ALMA band 7 observations, G188.95+0.89 MM2 was resolved into two continuum cores separated by 0.1 arcsec. The thermal emission of CH3OH (4(2, 2) - 3 (1, 2)) linked with MM2 has a double peak. In MM2, SiO emission has a bow-shock morphology, but high 12CO evidence for an east-west bipolar outflow is provided by emission to the east and west of MM2. SiO emission shows bipolar outflow centered around MM2 core. Using near- and mid-IR color-color diagrams, young sources were detected in this star-forming region. A total of 36 candidate YSOs, were detected within a 60′′ radius of the G188.95+0.89 source. There is an IR cluster made up of nine of these YSOs just outside the UC HII zone. Only the H and Ks bands of the 2MASS data can reveal nine highly red shifted objects. These sources have redder colors than H − K > 2, indicating that the IR cluster is extremely young. It is unlikely that interstellar absorption alone is responsible for the reddening of the vectors; instead, the presence of a circumstellar disc and envelope must account for at least some of the IR excess. Although further investigation is needed, it appears that the velocity drifts were caused by gas falling into the inner radius of the accretion disk surrounding the protostar G188.95+0.89. The variability of 6.7 GHz methanol masers is a confirmation of on going accretion in the source. Although the presence of accretion disks in the source cannot be confirmed with the existing measurements, the identification of outflows is consistent with their existence. The out-flowing material creates shocks when it encounters the quiescent gas of the envelop. The detection of SiO molecular lines is an effective tool for checking for the existence of shocks. The shock waves pushes the gas into ever denser physical states that allow it to cool and fragment more efficiently. We argue that MM2 has a massive multiple (at least binary) of young star objects, but more VLBI observations are needed to confirm that this is indeed the case.
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    PHYLOGENETIC DIVERSITY AND TOXIGENIC POTENTIAL OF FUSARIUM SPECIES IN WHEAT AND LEVELS OF DEOXYNIVALENOL AND FUMONISINS IN MARKET WHEAT PRODUCTS, KENYA
    (Technical University of Kenya, 2023-11) OTIENO, PHANICE KHESELI
    ABSTRACT In Kenya, wheat is the second most consumed cereal grain after maize and provides nutrition for about 50% of the world's population. However, production of the grain often faces setbacks occasioned by fungal infections and the related chemical contaminants. Unrelenting fungal disease control system, sufficient wheat seed system and observation of food safety measures to curb deficiency and alleviate ill health associated with consumption of mycotoxin contaminated wheat products is essential. This study assessed farmers’ knowledge on fungal wheat diseases and, their practices in choices of wheat cultivars cropped in three ecological regions of Kenya. Prevalence and diversity of Fusarium species in the produce of farmer saved and certified seeds of wheat cultivars was also analyzed. In addition, the genetic ability of the isolated Fusarium spp. to produce mycotoxins was evaluated. Lastly, a survey to investigate occurances and levels of fumonisins and deoxynivalenol (DON) in selected market wheat products sampled in Narok town, Nakuru city and Nairobi, the capital city of Kenya was done. Two hundred and sixty wheat grain samples were collected from 123 farms in Narok, Uasin Gishu and Nakuru Counties between 2016 and 2017. Peptone Pentachloro-nitrobenze Agar was used for isolation of Fusarium spp. from the grains samples, while PDA, CLA and SNA media were used for cultural and morphological characterization. Fusarium species identity and diversity was determined using sequence analysis of the gene encoding translation elongation factor 1-alpha (tef1-alpha). The genetic ability of the Fusarium spp. to produce mycotoxins was determined using Tri13F/Tri13RDON and FUM1F/FUM1R primer pairs. ELISA Kit protocols were used for assessment of mycotoxin levels. ANOVA, the Tukey HSD test and microscopy were used for data analysis. Notably, barely 10% of wheat cultivars released into the Kenyan market were under cultivation in the targeted areas within the study period. In all the three regions, Njoro BWII wheat cultivar was the most preferred and the most frequently (48.8%) sampled wheat cultivar. Top on the list of agroeconomic factors that influenced the selection of wheat cultivars to plant were the weight of wheat grains at harvest and the resilience of wheat cultivars to wheat rust. Other than wheat rust, most farmers had limited knowledge about other fungal diseases while only 1.63% of them cited Fusarium head blight (FHB) as a problematic fungal disease in wheat production. Eight Fusarium spp. (Fusarium poae, F. verticillioides, F. equiseti, F. heterosporum, F. tricinctum, Fusarium sp. F. oxysporum, and F. culmorum) were identified. However, the species diversity in the study regions did not differ significantly. While certified commercial wheat seeds produced 33.75 percent of the recovered Fusarium spp., wheat grains from farmer-saved seeds produced 66.25%. Tri13DON gene was not detected in the isolated putative DON producers while FUM1 gene was detected in 60% of the isolated Fusarium species. Over 76% of the analyzed wheat grain samples had detectable levels of fumonisins. However, the highest level (9.6ppm) did not exceed the permissible levels of between 2000μg/kg and 4000μg/kg in whole grains according to EU guidelines. Over 75% of the sampled market wheat products contained levels of DON and fumonisins that were below the permissible maximum limits of 750μg/kg according to EU guidelines. Wheat flour contained the highest concentration of DON (5.6 μg/kg). The significant research finding is that a minimal percentage of wheat cultivars released into the market had been cultivated in the studied regions. Among other factors, farmers did not prioritize selection of cultivars based on their ecological growth requirements and they notably had minimal knowledge about other serious wheat fungal diseases such as FHB to the extend of referring to all diseases observed on the crop as wheat rust. Fusarium spp. with the ability to produce mycotoxins were prevalent in the wheat cultivars sampled in the three study areas. This calls for intensified integrated control measures of the pathogens across the three regions. Finally, the quantities of DON and fumonisin found in the wheat products from the market samples were within acceptable limits. Hence, this result highlights the safety of the products for human consumption. However, frequent surveys are recommended to ascertain consistency in the levels of the toxins within the recommended measures. More extension services are also needed to educate wheat farmers on all-important qualities of wheat cultivars released in the market. Lastly, enhancement of awareness on the prevalence of other dangerous fungal diseases such as FHB, it’s related health affecting mycotoxins and how farmers can participate in the control of such diseases.