Kenyatta University Repository
Kenyatta University Institutional Repository is a digital archive that collects, preserves and disseminates scholarly outputs of the Institution
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A Comparative Evaluation of Antibacterial Activity of Metallic Nanoparticle Formulations Synthesized Using a Poly(amic) Acid
(sage journal, 2025-11-06) Obumba, Maxwell; Naumih Noah; Nawiri,Mildred
Water is considered one of the most abundant natural resources, covering the largest proportion of the Earth’s total surface. The availability of clean and safe water for domestic use, however, remains the most important scientific and technological challenge facing humanity presently. Disposal of human organic waste containing large volumes of deadly microbes, including Streptococcus aureus and Escherichia coli, has been cited as the major cause of water pollution and contamination. The increasing prevalence of these antibiotic-resistant pathogens in major water sources presents a critical challenge to public and environmental sustainability. Addressing this challenge calls for the development of novel, effective antimicrobial agents. This study reports the effect of synthesis temperature on the particle size and dispersion, which in turn influence the antimicrobial activity of silver (Ag), gold (Au), and bimetallic silver/gold (Ag/Au) nanoparticles synthesized and stabilized with a biodegradable poly(amic) acid PAA-polymer against S. aureus and E. coli. The synthesis of the different nanoparticle formulations was carried out in two different sets of temperatures: ambient (25 °C) and elevated temperatures (70 °C). The elevated temperature was kept at 70 °C to minimize imidization of PAA to polyimides, a process which occurs at temperatures above 100 °C. This ensured that the stability and structural integrity of PAA were preserved throughout the synthesis process. Nanoparticles synthesized at both ambient and elevated temperatures were characterized by cyclic voltammetry, ultraviolet–visible spectroscopy, and transmission electron microscopy. The results revealed spherical particles sized between 25 and 58 nm, with elevated temperatures yielding smaller, more uniformly dispersed nanoparticles. Elevated temperatures exhibited enhanced antibacterial activity against E. coli and S. aureus using disk diffusion assays. A higher antimicrobial activity exhibited by the bimetallic Ag/Au nanoparticles synthesized at elevated temperatures (Ag/Au NPs-HT) showed superior inhibition zone against E. coli (27.67 ± 1.53 mm) and S. aureus (23.67 ± 0.58 mm), outperforming their counterparts synthesized at ambient temperature (p = 0.0088; for E. coli) and all monometallic nanoparticles (p < 0.0001 for both S. aureus and E. coli). Statistically, Ag/Au NPs-HT exhibited a stronger antimicrobial activity as compared to Vancomycin, a commercial clinical antibiotic against both S. aureus (p < 0.0007) and E. coli (p < 0.0007). These findings highlight a synergistic effect when combining silver and gold and underscore synthesis temperatures as a crucial factor in optimizing the antimicrobial performance of Nobel metal nanoparticles, with potential application in environmentally sustainable and cost-effective water purification systems.
Fiscal Devolution And Technical Efficiency Of County Governments In Kenya
(IOSR-JEF, 2026-01-07) Nyaoko, John Mose; Njaramba, Stephen Githae; Korir, Julius
Several fiscal decentralization and revenue independence programmes have been instituted since independence in Kenya in order to attain technical efficiency in the delivery of public goods and services. Notably, the enactment of the Constitution 2010 ushered in fiscal devolution as the main driver of economic growth through technical efficiency in delivering public goods and services. Technical efficiency is to be attained through reduction in costs associated with allocations and rent-seeking activities as they focus on transparency and allocative efficiency. A smaller and productive government is believed to enhance technical efficiency by reducing wastage of expenditure and raising income growth. However, being responsible for a larger fiscal capacity can offer both challenges and opportunities for local governments in developing countries. As the devolved funds increase to the counties in Kenya, it is expected that technical efficiency would also increase in the county public service provision as more inputs would be available in relatively small size government. Despite the fact that the allocations to counties have been increasing and increased independence through tax assignments, there seems to be no evidence of improved technical efficiency as there has been no significant improvement in provision of goods and services for devolved functions including health and agriculture. There has also been a decline in the county growth domestic product over the years. Additionally, revenue collections at the counties have remained low and declining, despite higher targets that are set by the county governments. The main objective of the study was to measure the technical efficiencies in the counties. Specifically, the study estimated technical efficiency index for the 47 county governments. The model used in the analysis was a Cobb Douglas Stochastic Frontier Analysis to compute the mean technical efficiency. The average technical efficiency across counties is 84 percent, implying an average of 16 percent technical inefficiency. Technical efficiency varies significantly across counties operating between 50 and 90 percent technical efficiency. Based on these findings, the study recommends that counties should optimize resource utilization to close the 16 percent efficiency gap.
Why Utilization of Infrastructural Resources is Key in Teaching and Achievement of Learning Outcomes in Biology: The Kenyan Experience
(International Journal of Research in Education Humanities and Commerce, 2025-06) Osugo, Roseline Moraa; Kaugi, Ephantus M.; Magoma, Charles M.
This article examines the extent to which both teachers and learners utilize infrastructural
resources to support the development of scientific understanding in Biology, particularly
through visualization of abstract concepts, hypothesis generation, critical analysis, and
reflective critic aimed at deepening comprehension. Further, the article assesses the extent to
which utilization of infrastructural resources in Biology teaching and learning influences the
achievement of learning outcomes in public secondary schools in Nairobi County, Kenya.
Adopting a mixed-methods approach within an explanatory sequential design, the research
commenced with a quantitative survey followed by in-depth qualitative inquiry in selected
secondary schools, informed by the survey results. The study was conducted in Nairobi City
County, encompassing 114 public secondary schools. Data collection tools included structured
questionnaires, in-depth interview schedules, focus group discussion (FGD) guides, and
classroom observation protocols. Participants comprised Biology teachers, students and subject
matter experts from the Kenya Institute of Curriculum Development (KICD), the Centre for
Mathematics, Science and Technology Education in Africa (CEMASTEA), and Biology
education lecturers from Kenyatta University. The findings reveal that the use of infrastructural
resources in Biology was limited and primarily facilitated the development of lower-order
cognitive abilities, basic scientific process skills, and a generally negative attitude towards the
subject. Thus, there is need to expand and diversify the use of infrastructural resources so as to
enhance the quality and depth of Biology education
Bioaccessibility of Vitamins and Minerals in Processed Tubers and Leaves of Manihot esculenta Crantz Varieties
(Journal of Food Quality, 2024) Ogombe C. Ojiambo; Nawiri P. Mildred; Nyambaka,Hudson
Manihot esculenta Crantz (cassava) is an important food crop in developing nations, with its tubers and leaves being a source of
ascorbic acid, thiamin, ribofavin, and niacin (vitamins) and calcium, iron, potassium, and zinc (minerals). Malnutrition
prevalence in some Kenyan Counties that relied on cassava-based diets has partly been attributed to processing methods and/or
nutrient bioaccessibility. Te study area Kilif County grows Kibandameno and Tajirika cassava varieties and is on record for high
prevalence of undernutrition. Te levels of vitamins and minerals, and their bioaccessibility in raw, boiled, and deep-fried tubers,
and pounded then boiled leaves of Kibandameno and Tajirika cassava varieties were studied. Digestion was done using static
gastrointestinal digestion prior to the determination of vitamins (by HPLC) and minerals (by AAS and AES). Bioaccessibility of
both vitamins and minerals was signifcantly higher (P < 0.001) in boiled followed by deep-fried and lowest in raw tubers.
Bioaccessibility ranged between 27% (Fe)–85% (vitamin C) in boiled, 20% (Fe)–79% (vitamin B1) in deep-fried, and 15%
(Fe)–(72% (K) in raw tubers. Bioaccessibility in processed leaves was signifcantly higher (P < 0.001) than in raw. Tis ranged
between 11% (Fe)–81% (vitamin B1) in processed and between 8% (Fe)–67% (K) in raw leaves. Processing therefore signifcantly
reduced levels of ascorbic acid, thiamin, ribofavin, niacin, calcium, iron, potassium, and zinc in raw tubers and leaves of
Kibandameno and Tajirika Manihot esculenta Crantz varieties. Teir bioaccessibility however signifcantly increased, being higher
in tubers than in leaves
Pedagogical Content Knowledge andStudents’ Academic Achievement in Kiswahili: A case of Public Secondary Schools in Murang’a and Kiambu Counties
(EdinBurgPeer Reviewed Journals and BooksPublishers, 2025-02) Munyaka Lucy Wanjiru; Bunyi, Grace; Itolondo, Wilfrida
Purpose:Teachers have a vital effect on students’ academic attainment because they are responsible for implementing the school curriculum. The steady decline in educational performance of secondary school students has caused a lot of attention among backers in the education sector in Kenya. This study sought to investigate the influence of Teachers’ Pedagogical Content Knowledge (PCK) on students’ academic achievement in Kiswahili at KCSE examinations in Kiambu and Muranga counties.Methods:A descriptive research design of survey type was used. The target population was 29,134 comprising 512 principals, 1,172 teachers, and 27,450 students across 512 secondary schools in Murang’a and Kiambu counties. Descriptive statistics such as frequencies, percentages, and standard deviation was used to analyze the data.Results:The study established that teachers Pedagogical Content Knowledge positively influenced student academic achievement in Kiswahili at KCSE, (M = 4.0, SD = 1.1. Implication:The findings emphasize the complexity of teachers’ factors affecting students’ academic achievement. Conclusively every practicing teacher should enroll in a teacher performance development program initiated by TSC to enhance and update teacher pedagogical content knowledge in teaching for an impressive students’ academic achievement