Theses and Dissertations

Prevalence and Factors Associated with Psoriatic Arthritis among Psoriasis Patients on Followup at the Dermatology and Rheumatology Units in Kenyatta National Hospital, Kenya

Thu, 28 May 2026 00:00:00 GMT

Prevalence and Factors Associated with Psoriatic Arthritis among Psoriasis Patients on Followup at the Dermatology and Rheumatology Units in Kenyatta National Hospital, Kenya Achungo, Jane Maureen Psoriatic arthritis (PsA) is a serious and potentially debilitating condition that frequently occurs in approximately 30% of individuals with psoriasis. The burden of PsA ranges between 6 – 42 percent globally and occurs in approximately 30% of patients with psoriasis. However, the burden of PsA has not been fully investigated within the local context. The main study purpose was to determine the prevalence and clinical factors associated with psoriatic arthritis among psoriasis patients on follow-up at the Dermatology and Rheumatology units, Kenyatta National Hospital, Kenya. This was a cross-sectional study conducted at Kenyatta National Hospital over a period of five months. A consecutive sampling technique was used to sample 80 patients diagnosed with psoriasis. A structured questionnaire was used to collect data. The CASPAR criteria were used to screen for PsA. The prevalence of PsA was obtained as a proportion of patients with PsA over the total sample size and expressed as a percentage. Bivariate and multivariable analyses were done to investigate factors associated with PsA using binary logistic regression. A STATA version 16 was used to analyze the data. The findings indicated that the majority of the patients were male (65%), 47.5% were aged between 31 and 49 years, with the youngest being four years and the oldest being 75 years. Further, 52.5% had psoriasis for more than 48 months, and 33.8% had a family history of psoriasis with a first degree relative. The average PASI score was 11.5 (SD=8.9). The common type of psoriasis was plaque (70%), and the common site of psoriasis included the extremities (78.8%). The prevalence of psoriatic arthritis was 23(28.8%) with a 95%CI: 19.4% to 40.2%. The common psoriatic arthritis subtypes included polyarticular arthritis (39.1%), spondylarthritis (26.1%), and oligoarticular arthritis (21.7%). The multivariable analysis revealed that significant factors associated with Psoriatic Arthritis include gender (females, aOR = 10.11, 95% CI: 1.12, 91.61, p = 0.040), history of smoking (aOR = 21.37, 95% CI: 2.45, 186.71, p = 0.006), nail involvement (aOR = 5.44, 95% CI: 2.69, 42.1, p = 0.006), onycholysis morphology (aOR = 11.39, 95% CI: 1.42, 91.50, p = 0.022), oil drops (aOR = 12.11, 95% CI: 1.44, 34.12, p = 0.034), and the PASI score (aOR = 2.11, 95% CI: 1.34, 6.11, p < 0.001). The study concluded that Psoriatic arthritis (PsA) burden is high, with polyarticular arthritis being the most common subtype. Female gender, smoking history, nail involvement, onycholysis morphology, oil drops, and a higher PASI score are key contributors to the likelihood of developing PsA. Early monitoring for these factors is recommended. Master of Medicine in Dermatology

Experimental Study and Numerical Optimization of a Thermal Swing Adsorber for Biogas Upgrading

Thu, 28 May 2026 00:00:00 GMT

Experimental Study and Numerical Optimization of a Thermal Swing Adsorber for Biogas Upgrading Mutunga, Jackline Mwende Biogas is a renewable energy source that can be adopted as a reliable and sustainable alternative when upgraded. The composition of carbon dioxide in biogas of up to 45% reduces its energy density. Thermal swing adsorption has proven to be a promising technology in the biogas upgrading process, due to its ease of integration with renewable electricity sources and its suitability for water-deficient areas. The experimental study of the biogas upgrading process has been complicated by the dynamic nature of the process and the high sensitivity to operating conditions, such as pressure, temperature, and gas flow rate. To understand the complex interaction between the process parameters, numerical simulation was utilised. There are, however, limited numerical studies evaluating multi-objective optimization of these process parameters. This study assessed the performance of thermal swing adsorption technology, utilising resistive heating, in upgrading biogas produced from the anaerobic digestion of organic waste. Commercial coconut shell-based activated carbon was used as an adsorbent in the experimental cyclic process to capture carbon dioxide. Aspen Adsorption software was used to develop a thermal swing adsorption numerical model. The simulation model was validated using experimental data obtained from a laboratory-scale setup. A good agreement was observed between the simulation and experimental carbon dioxide breakthrough times, with a mean absolute percentage error of 2%. Dynamic adsorption tests were conducted to evaluate the system performance in carbon dioxide capture. The maximum resistive heating regeneration temperature of 60℃ resulted in a peak carbon dioxide concentration of 39% in the waste gas, an energy requirement of 0.1538 kWh per cycle, and an energy efficiency of 87%. This was a good trade-off between adsorbent recovery for subsequent biogas upgrading cycles and system energy efficiency. In the second phase of the study, the adsorbent particle radius, regeneration temperature, and purge-to-feed flow rate ratio were investigated to determine the system's sensitivity. The adsorption and desorption processes were based on methane and carbon dioxide adsorption isotherms, which were fitted to the Langmuir-Freundlich model. The model described the adsorption behaviour on a heterogeneous adsorbent surface, where adsorption sites had different affinities and capacities. Adsorbent particle radius, steam regeneration temperature, and purge-to-feed flow rate ratio range of 1 to 9 mm, 77 to 227℃, and 0.1 to 0.7, respectively, were adopted. Multi-objective numerical optimization of the selected variables was carried out using the Box-Behnken design response surface methodology. The target output responses maximized were the methane purity and recovery. From the analysis of variance, the purge-to-feed flow rate ratio made the highest contribution to both methane purity and recovery, of 92.37% and 99.90%, respectively. While the particle radius had a negligible influence on the methane recovery model, its contribution to the methane purity was significant. The optimal values for maximum methane purity and recovery obtained were 82.12% and 37.21%, respectively, achieved at a particle radius of 9 mm, steam regenerating temperature of 227℃, and a purge-to-feed flow rate ratio of 0.4152. This study offers valuable insights into the design of a thermal swing adsorption biogas upgrading model, as well as the impact of various variables and configurations on the process. The developed model provides practical guidelines for selecting optimal biogas upgrading process parameters to maximize both methane purity and recovery. Doctor of Philosophy in Mechanical Engineering

Prevalence of Renal Insufficiency in Patients with Major Cancers and Associated Factors at Kenyatta National Hospital, Nairobi, Kenya

Thu, 28 May 2026 00:00:00 GMT

Prevalence of Renal Insufficiency in Patients with Major Cancers and Associated Factors at Kenyatta National Hospital, Nairobi, Kenya Qalicha, Gabriel Dokata Renal insufficiency, defined as a reduction in kidney function, represents a major global health challenge, affecting about 10% of the world’s population. In sub-Saharan Africa, the burden is estimated at 14%, while Kenya reports a prevalence of approximately 4% in the general population. Among cancer patients, earlier studies indicate that up to 27.1% experience renal insufficiency, often necessitating chemotherapy dose adjustments. This study aimed to determine the prevalence of renal insufficiency and identify associated demographic, clinical, and treatment-related factors among cancer patients receiving care at Kenyatta National Hospital. A cross-sectional study design was employed, involving 335 systematically selected oncology patients from KNH wards and clinics. Data were collected through structured interviewer-administered questionnaires and review of hospital records. After exclusion of five participants due to incomplete data, 330 patient records were analyzed. Data entry, cleaning, and analysis were conducted using R (version 4.1.2). Estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI micromole/L calculator to diagnose and stage renal insufficiency. Descriptive statistics summarized patient characteristics, while associations between renal insufficiency and demographic, clinical, and treatment variables were assessed using bivariate and multivariable logistic regression. Statistical significance was set at p<0.05. Among the 330 participants, 56.1% were female. Most patients were aged 41–60 years (42.7%), followed closely by those above 60 years (41.5%). The overall prevalence of renal insufficiency was high at 38% (95% CI: 33–44%). Majority of patients had mild renal impairment (eGFR 61–89 mL/min/1.73 m²) accounting for 29.4% of cases whereas severe stages were less common, with stage 4 observed in (2)0.6% and stage 5 in (3)0.9% of patients. Multivariable logistic regression revealed two significant associations. Patients older than 60 years had a more than two-fold higher likelihood of renal insufficiency (AOR=2.33; 95% CI: 1.16–4.87; p=0.020). Conversely, the use of taxane-based chemotherapy was associated with a lower prevalence of renal insufficiency (AOR=0.47; 95% CI: 0.25–0.85; p=0.015). The study concludes that renal insufficiency is common among cancer patients at KNH, with advanced age posing a significant risk. Close monitoring of renal function, especially in elderly patients undergoing cancer treatment, is strongly recommended. Master of Medicine (Internal Medicine)

Development of Sorghum-Wheat Buns Enriched with Giant African Land Snail Meat Powder for Improved Protein among Children Aged 3-10 Years

Thu, 28 May 2026 00:00:00 GMT

Development of Sorghum-Wheat Buns Enriched with Giant African Land Snail Meat Powder for Improved Protein among Children Aged 3-10 Years Agengo, Fredrick Benard Protein nutrition is important for human health because its deficiency results in public health problems such as Protein Energy Malnutrition (PEM). The situation is worse among children aged 3 to 10 years, a critical stage of physical development, where undernutrition results in irreversible effects, including delayed physical and cognitive development, as well as increased risk of infections and even mortality. Formulating cereal-based diets enriched with animal protein has been proposed as the most practical strategy to improve the nutritional quality of the diet. Buns are appropriate food vehicles because of their popularity among all age groups in rural and urban settlements due to their attractive features, including good eating quality, low cost, varied taste, and relatively long shelf-life. The main objective of this study was to formulate and develop sorghum-wheat buns enriched with snail meat powder for improved protein intake. Buns were prepared by replacing part of the sorghum-wheat flour with 5, 10, 15, 20, and 25% of SMP. Physical properties of volume, density, baking loss, yield, weight, hardness, and colour, proximate analyses including moisture, crude protein, crude fat, crude fibre, and ash, and mineral composition of iron, zinc, calcium, copper, and magnesium were determined for the buns. In vitro protein digestibility was tested using a single-enzyme assay with pepsin, whereas plate count agar and potato dextrose agar were used to enumerate the fungal and bacterial flora contaminating the buns during storage. Shelf-life determination for the buns was based on the number of days before the production of off-flavours and the presence of a fungal infestation. The protein nutritional quality of buns was evaluated on a Complete Randomized Design (CRD) with diets as treatments. Rats were randomly assigned to groups based on weight, forming the blocks, and each treatment was replicated three times within each block. Male weanling albino rats (Sprague Dawley) were used to determine the indices of PER, FER, NPRR, APD, and TPD. Bun amino acid efficiency was calculated using PDCAAS and DIAAS. Descriptive sensory and consumer acceptability with children followed RCBD that evaluated six variations of buns as treatments, which were randomized and replicated thrice with panelists as units and sessions as blocks. The adult consumer studies were based on the CRD approach. Randomized three-digit codes were assigned to the bun for blinding purposes, with sample arrangement on trays randomized for each panelist. The evaluation process was also randomized, with evaluators coming to the evaluation room at random to evaluate samples for acceptability. A descriptive panel was used to characterize the buns, and a consumer panel for acceptability using a 7-point facial scale with school children of 8-9 years old. Compositing with SMP progressively improved the buns' density, baking loss, yield, weight, and texture. Protein, fat, ash, energy, iron, zinc, calcium, magnesium, and copper were also increased. Enriching buns with between 5% and 25% SMP improved in-vitro protein digestibility. The maximum bacterial count in buns was below the International Microbiological Standard recommended units for dry and ready-to-eat foods of 103 cfu/g. Enriching with SMP also significantly (P<0.05) enhanced protein efficiency ratio from 0.21% to 2.70%, food efficiency ratio from 0.02% to 0.27%, apparent protein digestibility from 81.17% to 88.28%, and true protein digestibility from 87.48% to 95.38%. Protein digestibility corrected amino acid score, and the digestible indispensable amino acid score increased from 45% to 78% and 44% to 69%, respectively, in unenriched buns to buns enriched with 25% SMP. Principal Component Analysis (PCA) revealed 99% total variation of 23 attributes for buns scored by a descriptive sensory panel, of which 98% was due to the proportion of SMP that replaced sorghum-wheat composite flour in buns, and the remainder 1% was due to the buns’ physical appearance. Compositing sorghum-wheat buns with SMP imparts positive consumer attributes of fine crumb, sponginess, and crumby texture. Positive sensory score by school children of 8 to 9 years old for enriched buns was sustained throughout the three consumption sessions. The data obtained in this study indicate that incorporation with SMP imparted positive sensory characteristics associated with buns to the sorghum-wheat buns, and acceptance of such buns may be sustained over an extended period. Compositing sorghum-wheat flour with SMP is beneficial in formulating buns with superior protein and mineral quality in proportion to the amount of SMP added. Enriching with SMP also imparts positive physical characteristics of higher density, yield, and weight, reduces bun hardness and baking loss, and promotes better-keeping quality. In addition, enriching only at 5% with SMP significantly improved in vitro protein digestibility by 29% compared to the control. Enriching with SMP signiﬁcantly promotes growth in rats, improves net protein retention, protein retention ratio, true protein digestibility, and protein digestibility corrected amino acid score of the sorghum-wheat buns to levels considered potential for use as supplementary or rehabilitation diets. Buns enriched at 25% with SMP have protein quality that promotes catch-up growth in emaciated rats, as assessed by the PER. Therefore, has the potential to alleviate PEM among children in developing countries. Doctor of Philosophy in Food Science and Nutrition