Department of Biological and Environmental Sciences

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Pyro-processed Coconut Fibre for Removal of Lead Ions from Aqueous Solution
(American Journal of Chemistry and Pharmacy, 2026-05-25) Kasimu, Titus M.; Maingi, Francis M.; Mbuvi, Harun M.; Ng’ang’a, Margaret M.; Abdulhameed, Adamu
Approximately 80% of the population in developing countries lacks access to clean, safe water. A major source of water contamination is heavy metal ions, which pose great risks to human health. This is expected to increase with the projected population and industrial growth if immediate remediation is not taken. Current operational methods for removing the heavy metal ions in wastewater include: chemical coagulation, ion exchange, electrochemical methods, adsorption using activated carbon, natural zeolite, membrane process, ultra-filtration, among others, which are uneconomical due to high costs and unaffordable to low-income earners. Coconut fibres are locally available agricultural waste that can be converted by activation into adsorbents for water remediation due to their fineness and large surface area. This study reports the synthesis and characterization of coconut fibre charcoal (CFC) and activated coconut fibre charcoal (ACFC) to remediate water contaminated with Pb2+ ions. This involved burning dry coconut fibre in a limited amount of air to obtain coconut fibre charcoal followed by dissolving fine powder of charcoal in 2 M phosphoric acid for 24 hours at a temperature of 25 ºC to obtain activated coconut fibre charcoal. The adsorbents were characterized using FT-IR and SEM. Batch sorption studies were carried out while varying parameters of contact time, shaking speed, temperature, adsorbent dose, pH, and initial concentration of metal ions in solution. Residue Pb2+ ion concentrations were determined using atomic absorption spectroscopy (AAS). The FT-IR results showed absorption peaks at 1423 cm-1 and 840 cm-1 attributed to symmetric –COO- stretch and -OH deformation in ACFC adsorbent, these peaks shifted to 1384 cm-1 and 813 cm-1 while PO4- aromatic strain vibration in ACFC disappeared upon saturation of ACFC with Pb2+ ions respectively. SEM analysis showed pores of different sizes and shapes in ACFC compared to a rigid, concrete, and smooth surface upon saturation with Pb2+ ions. Adsorption data for Pb2+ ions best fitted into the Freundlich model with maximum adsorption capacities of 32.09 mg lead/g activated coconut fibre charcoal. The results from this study suggest that coconut fibre charcoal and activated coconut fibre charcoal are potential adsorbents of Pb2+ions.
Evaluating the Adsorption of Reactive Red Dye Using Natural Zeolite: The Role of Solution Aging
(Advances in Analytical Chemistry, 2026-05-08) Yego, Sharon; Maingi, Francis; Ouma, Linda Immaculate
Reactive dye pollution is a major environmental problem in the textile industry. The study investigated the impacts of dye aging on the adsorption of reactive red dye using the natural zeolite. The natural zeolite was characterized by various methods, including X-ray fluorescence (XRF) and Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscopic analysis. The pH and absorbance of the dye solutions were affected by the aging of the dye solutions, which led to a decrease in removal efficiency and adsorption capacity as aging progressed. The results showed that fresh dye solutions were adsorbed more efficiently than aged dye solutions, and the Freundlich isotherm showed the best fit to the experimental data. It indicates that the adsorption took place on the heterogeneous surface of the zeolite. The results suggest that the history of the dye solutions should be taken into account in adsorption studies for better remediation strategies.
Synthesis of Silicon Nitride from Rice Husk and Sugarcane Bagasse Ashes
(Journal of Water technology and Treatment methods, 2018-01-22) Abdulhameed, Adamu; Mbuvi, Harun M.; Changamu, Evans O; Maingi, Francis M.
Silicon nitride (Si3N4) SNA, SNB, SNC and SND were synthesized by hydrothermal process at temperature of 100oC, 150oC, 200oC and 300oC using Rice Husk Ash (RHA) and Sugarcane Bagasse Ash (SBA) respectively. The percentage of silica ranges from 90.10 to 94.19 with minute impurities.Based on their infrared spectra, for SNA absorption band at 470.6 cm-1 is attributed to Si-N (stretching), which were also observed with SNB, SNC and SND, a weak band at 671.2 cm-1 which is characteristic of a silicon nitride Si-N-Si stretching vibration was observed, for SNC, peak at 574 cm-1 attribute to α-silicon nitride, as temperature increases the spectrum becomes sharper. X-ray diffraction pattern indicates that SNA material contained 64.6% α-phase and 27.8% β-phase silicon nitride. Therefore, rice husks and sugarcane bagasse have great potential as a raw material for producing Si3N4, by the hydrothermal method
Microwave synthesis of Carboxymethylcellulose (CMC) from Rice Husk
(IOSR Journal of Applied Chemistry, 2019-12-07) Abdulhameed, Adamu; Mbuvi, Harun M.; Changamu, Evans O.; Maingi, Francis M.
Carboxymethylcellulose is an important non-toxic cellulose derivative which plays vital roles in paper coating, pharmaceuticals, food, detergents, and others. Research work involving the extraction of cellulose from agricultural biomass and its modification cellulose using a microwave has been reported, but not much work has been done on the rice husk, thus helping in managing associated waste. In this study, cellulose extracted from rice husks was used as the raw material for the synthesis of food-grade carboxymethylcellulose (CMC). In the process of the synthesis of carboxymethylcellulose from rice husk, cellulose was carried out by alkalization, an etherification process, using sodium hydroxide (NaOH) and monochloroacetic acid (MCA). Characterizations of CMC products was carried out by Fourier Transform Infrared (FTIR) spectroscopy and Xray Diffraction (XRD). The reaction conditions optimized include power (microwave), sodium hydroxide concentration, amount of monochloroacetic acid and reaction time. The degree of substitution (DS) was determined using a potentiometric titration method and the maximum DS of 0.79 was obtained when 30% NaOH was used.
Spatial distribution and consumption patterns of Woodfuel in Sabatia Division, Kenya
(Journal of technology and socio-economic development, 2011) Beru, Festus K.
In the second phase of the Smallholder Dairy Research and Development Project (SDP), as well as continuing work in central Kenya, attention will be given to Western Kenya where lessons learnt from the Central and Coast regions of Kenya will be applied. Western Kenya shares a number of features that present an opportunity for smallholder dairy research and development. The climate is favourable for dairy production and average farm sizes are declining rapidly due to increasing population pressure. This study follows a sequential process Geographic Information Systems (GIS) analysis to identify potential sites, participatory rapid appraisals (PRAs) in the selected sites and characterization surveys. Each step informs the design and analysis of next study, building each time a better knowledge and understanding of smallholder agriculture and dairy systems and the constraints and refining the recommendation domains for the pilot interventions to be selected with farmers, market agents, regulators and policy makers.
Reorganization of cytoskeleton during surfactant secretion in lung type II cells: a role of annexin II
(Elsevier, 2003) Singh, Taran K.; Abonyo, B. O.; Narasaraju, Telugu A.
The secretion of lung surfactant requires the movement of lamellar bodies to the plasma membrane through cytoskeletal barrier at the cell cortex. We hypothesized that the cortical cytoskeleton undergoes a transient disassembly/reassembly in the stimulated type II cells, therefore allowing lamellar bodies access to the plasma membrane. Stabilization of cytoskeleton with Jasplakinolinde (JAS), a cell permeable actin microfilament stabilizer, caused a dose-dependent inhibition of lung surfactant secretion stimulated by terbutaline. This inhibition was also observed in ATP-, phorbol 12-myristate 13-acetate (PMA)- or Ca2 + ionophore A23187-stimulated surfactant secretion. Stimulation of type II cells with terbutaline exhibited a transient disassembly of filamentous actin (F-actin) as determined by staining with Oregon Green 488 Phalloidin. The protein kinase A inhibitor, H89, abolished the terbutaline-induced F-actin disassembly. Western blot analysis using anti-actin and anti-annexin II antibodies showed a transient increase of G-actin and annexin II in the Triton X-100 soluble fraction of terbutaline-stimulated type II cells. Furthermore, introduction of exogenous annexin II tetramer (AIIt) into permeabilized type II cells caused a disruption in the cortical actin. Treatment of type II cells with N-ethylmaleimide (NEM) resulted in a disruption of the cortical actin. NEM also inhibited annexin II’s abilities to bundle F-actin. The results suggest that cytoskeleton undergoes reorganization in the stimulated type II cells, and annexin II tetramer plays a role in this process. D 2003 Elsevier Inc. All rights reserved.
Syntaxin 2 and SNAP-23 are required for regulated surfactant secretion
(2014) Abonyo, B. O.; Wang, Pengcheng; Lin Liu
The secretion of lung surfactant in alveolar type II cells is a complex process involving the fusion of lamellar bodies with the plasma membrane. This process is somewhat different from the exocytosis of hormones and neurotransmitters. For example, it is a relatively slower process, and lamellar bodies are very large vesicles with a diameter of approximately 1 microm. SNARE proteins are the conserved molecular machinery of exocytosis in the majority of secretory cells. However, their involvement in surfactant secretion has not been reported. Here, we showed that syntaxin 2 and SNAP-23 are expressed in alveolar type II cells. Both proteins are associated with the plasma membrane, and to some degree with lamellar bodies. An antisense oligonucleotide complementary to syntaxin 2 decreased its mRNA and protein levels. The same oligonucleotide also inhibited surfactant secretion, independent of secretagogues. A peptide derived from the N-terminus of syntaxin 2 or the C-terminus of SNAP-23 significantly inhibited Ca(2+)- and GTPgammaS-stimulated surfactant secretion from permeabilized type II cells in a dose-dependent manner. Furthermore, introduction of anti-syntaxin 2 or anti-SNAP-23 antibodies into permeabilized type II cells also inhibited surfactant release. Our results suggest that syntaxin 2 and SNAP-23 are required for regulated surfactant secretion.
Modulation of eotaxin-3 (CCL26) in alveolar type II epithelial cells
(2007)
Airway epithelial inflammation associated with emphysema, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and asthma is regulated in part by alveolar type II cell chemokine signaling. Data suggest that resident lung cells use CCR3, CCR5 and CCR2 chemokine receptor/ligand systems to regulate the profile of leukocytes recruited in disease-associated inflammatory conditions. Thus studies were designed to test whether alveolar type II cells possess a Th1-activated CCR5-ligand system that modulates the Th2-activated CCR3/eotaxin-2 (CCL24), eotaxin-3 (CCL26) chemokine systems. The A549 alveolar type II epithelial-like cell culture model was used to demonstrate that alveolar type II cells constitutively express CCR5 which may be upregulated by MIP-1alpha (CCL3) whose expression was induced by the Th1 cytokines IL-1beta and IFN-gamma. Selective down-regulation of CCL26, but not CCL24, was observed in CCL3 and IL-4/CCL3 stimulated cells. Down-regulation was reversed by anti-CCR5 neutralizing antibody treatment. Thus, one mechanism through which Th1-activated CCCR5/ligand pathways modulate Th2-activated CCR3/ligand pathways is the differential down-regulation of CCL26 expression. Results suggest that the CCR3 and CCR5 receptor/ligand signaling pathways may be important targets for development of novel mechanism-based adjunctive therapies designed to abrogate the chronic inflammation associated with airway diseases.
Post-transcriptional silencing of CCR3 downregulates IL-4 stimulated release of eotaxin-3 (CCL26) and other CCR3 ligands in alveolar type II cells
(2008) Taka, Equar; Errahali, Younes J.; Abonyo, B. O.; Heiman, Ann S.
Trafficking and inflammation in airway diseases are, in part, modulated by members of the CC chemokine family, eotaxin-1 (CCL11), eotaxin-2 (CCL24), and eotaxin-3 (CCL26), which transduce signals through their CCR3 receptor. In this context, we hypothesized that transfecting alveolar type II epithelial cells with CCR3-targeted siRNA or antisense (AS-ODN) sequences will downregulate cellular synthesis and release of the primary CCR3 ligands CCL26 and CCL24 and will modulate other CCR3 ligands. The human A549 alveolar type II epithelium-like cell culture model was used for transfection and subsequent effects on CCR3 agonists. siRNAs were particularly effective. PCR showed a 60–80% decrease in mRNA and immunoblots showed up to 75–84% reduction of CCR3 in siRNA treated cells. CCR3-siRNA treatments reduced IL-4 stimulated CCL26 release and constitutive CCL24 release by 65% and 80%, respectively. Release of four additional CCR3 agonists RANTES, MCP-2, MCP-3 and MCP-4 was also significantly reduced by CCR3-siRNA treatments of the alveolar type II cells. Activation of eosinophils, assessed as superoxide anion generation, was reduced when eosinophils were treated with supernatants of A549 cells pretreated with CCR3-targeted siRNAs or AS-ODNs. Collectively, the data suggest that post-transcriptional regulation of CCR3 receptors may be a potential therapeutic approach for interrupting proinflammatory signaling.
Cytokine-stimulated human lung alveolar epithelial cells release eotaxin-2 (CCL24) and eotaxin-3 (CCL26)
(Mary Ann Liebert, Inc, 2005) Heiman, Ann S.; Abonyo, B. O.; Darling-Reed, Selina F.; Alexander, Marilyn S.
Asthma is a complex inflammatory disease characterized by a prolonged underlying airway inflammation resulting from cytokine-orchestrated signaling between many types of cells, including airway epithelial cells. Trafficking, recruitment, and activation of cells in airway disease are, in part, modulated by the newly discovered CC subfamily of chemokines, eotaxin (CCL11), eotaxin-2 (CCL24) and eotaxin-3 (CCL26), which transduce signals by acting as agonists for the CCR3 receptor. The specific cytokine stimuli that modulate CCL24 and CCL26 release in airway epithelial cells remain poorly defined. Thus, human 549 alveolar type II epithelium-like cells were stimulated singly and with combinations of 1–100 ng/ml tumor necrosis-factor- (TNF- ), interleukin-1 (IL-1), and IL-4, cytokines known to be elevated in the airways of asthmatics. Release of CCL11, CCL24, and CCL26 was quantified by ELISA, and CCR3 receptors monitored by immunocytochemistry and FACS analysis. Results suggest that epithelial cells release CCL11 during the first 24 h of stimulation, in contrast to a significant increase in CCL24 and CCL26 release after 24–48 h of stimulation. Differential release of the eotaxins in response to cytokine combinations was noted. The alveolar type II epithelial cells were found to possess constitutive CCR3 receptors, which increased after proinflammatory cytokine stimulation. The airway epithelium CCR3 receptor/eotaxin ligand signal transduction system may be an important target for development of novel mechanism-based adjunctive therapies designed to interrupt the underlying chronic inflammation in allergic and inflammatory disorders.
CCL26-targeted siRNA treatment of alveolar type II cells decreases expression of CCR3-binding chemokines and reduces eosinophil migration: implications in asthma therapy
(2009) Errahali, Younes J.; Taka, Equar; Abonyo, B. O.; Heiman, Ann S.
The underlying infl ammation present in chronic airway diseases is orchestrated by increased expression of CC chemokines that selectively recruit leukocyte populations into the pulmonary system. Human CCL26 signals through CC chemokine receptor 3 (CCR3), is dramatically upregulated in challenged asthmatics, and stimulates recruitment of eosinophils (EOSs) and other leukocytes. CCL26 participates in regulation of its receptor CCR3 and modulates expression of a variety of chemokines in alveolar type II cells. Utilizing the A549 alveolar type II epithelial cell culture model, we carried out studies to test the hypothesis that CCL26-siRNA treatment of these cells would ameliorate Th2-driven release of the eotaxins and other CCR3 ligands that would, in turn, decrease recruitment and activation of EOSs. Results demonstrate that CCL26-siRNA treatments decreased interleukin4-induced CCL26 and CCL24 expression by > 70%. CCL26-directed small-interfering RNA (siRNA) treatments signifi cantly decreased release of CCL5 (RANTES), CCL15 (MIP-1δ), CCL8 (MCP-2), and CCL13 (MCP-4). In bioactivity assays it was shown that EOS migration and activation were reduced up to 80% and 90%, respectively, when exposed to supernatants of CCL26-siRNA-treated cells. These results provide evidence that CCL26 may be an appropriate target for development of new therapeutic agents designed to alleviate the underlying infl ammation associated with chronic diseases of the airways.
Characterization of -soluble n-ethylmaleimide–sensitive fusion attachment protein in alveolar type ii cells implications in lung surfactant secretion
(2002) Abonyo, B. O.; Wang, Pengcheng; Narasaraju, Telugu A.; Rowan III, William H.; Zimmerman, Un-Jin; Lin Liu
N-ethylmaleimide–sensitive fusion protein (NSF) and soluble NSF attachment protein (α-SNAP) are thought to be soluble factors that transiently bind and disassemble SNAP receptor complex during exocytosis in neuronal and endocrine cells. Lung surfactant is secreted via exocytosis of lamellar bodies from alveolar epithelial type II cells. However, the secretion of lung surfactant is a relatively slow process, and involvement of SNAP receptor and its cofactors (NSF and α-SNAP) in this process has not been demonstrated. In this study, we investigated a possible role of α-SNAP in surfactant secretion. α-SNAP was predominantly associated with the membranes in alveolar type II cells as determined by Western blot and immunocytochemical analysis using confocal microscope. Membrane-associated α-SNAP was not released from the membrane fraction when the cells were lyzed in the presence of Ca2+ or Mg2+ATP. The alkaline condition (0.1 M Na2CO3, pH 12), known to extract peripheral membrane proteins also failed to release it from the membrane. Phase separation using Triton X-114 showed that α-SNAP partitioned into both aqueous and detergent phases. NSF had membrane-bound characteristics similar to α-SNAP in type II cells. Permeabilization of type II cells with β-escin resulted in a partial loss of α-SNAP from the cells, but cellular NSF was relatively unchanged. Addition of exogenous α-SNAP to the permeabilized cells increased surfactant secretion in a dose-dependent manner, whereas exogenous NSF has much less effects. An α-SNAP antisense oligonucleotide decreased its protein level and inhibited surfactant secretion. Our results suggest a role of α-SNAP in lung surfactant secretion.
Autoregulation of ccl26 synthesis and secretion in a549 cells: a possible mechanism by which alveolar epithelial cells modulate airway inflammation
(2005) Abonyo, B. O.; Alexander, M. S. Alexander; Heiman, A. S.
Abonyo, B. O., M. S. Alexander, and A. S. Heiman. Autoregulation of CCL26 synthesis and secretion in A549 cells: a possible mechanism by which alveolar epithelial cells modulate airway inflammation. Am J Physiol Lung Cell Mol Physiol 289: L478 –L488, 2005. First published April 29, 2005; doi:10.1152/ajplung.00032.2005.— Eotaxins (CCL11, CCL24, CCL26) originating from airway epithelial cells and leukocytes have been detected in bronchoalveolar lavage of asthmatics. Although the alveolar epithelium is the destination of uncleared allergens and other inflammatory products, scanty information exists on their contribution to the generation and regulation of the eotaxins. We envisioned a state whereby alveolar type II cells, a known source of other inflammatory proteins, could be involved in both the production and regulation of CCL24 and CCL26. Herein, we demonstrated that all three eotaxins are constitutively expressed in A549 cells. IL-4 and IL-13 stimulated a concentration-dependent secretion of CCL24 and CCL26. The cytokines did not act synergistically. Cycloheximide and actinomycin D abrogated IL-4- and IL13-dependent CCL26 but not CCL24 secretion. Both IL-13 and IL-4 stimulated CCL26 synthesis that was inhibited in a concentrationdependent manner by CCL26 but not CCL24. Only CCL26 reduced expression of CCR3 receptors by 30 – 40%. On the other hand, anti-CCR3 pretreatment reduced IL-4 IL-13-dependent CCL26 secretion, implying autoregulation. A CCR3-specific antagonist (SB328437) significantly decreased IL-4-dependent synthesis and release of CCL26. Eosinophils treated with medium from IL-4-stimulated A549 cells preincubated with anti-CCL26 showed a marked decrease of superoxide anion production compared with anti-CCL24 treated. These results suggest that CCL26 is a major eotaxin synthesized and released by alveolar epithelial cells and is involved in autoregulation of CCR3 receptors and other eotaxins. This CCL26-CCR3 ligandreceptor system may be an attractive target for development of therapeutics that limits progress of inflammation in airway disease
Effective group learning: A case of perspectives from Kenyan high school students
(Eldoret Polytechnic, Kenya, 2013) Nashon, SM.; Anderson, D.; Ooko, S.; Beru, FK.; Okemwa, P.; Ombogo, P.
In this study we examined whether and how youth learned life skills through their involvement on a high school soccer team. We collected data from fieldwork and interviews with 12 male student-athletes and the head coach from one team. Results showed that the coach's philosophy involved building relationships and involving student-athletes in decision making. Issues relating to three life skills (initiative, re spect, and teamwork/leadership) were identified. Although we observed little direct teaching of these life skills, we saw that players generally were producers of their own experiences that supported the development of these skills.
Effective group learning: A case of perspectives from Kenyan high school students
(Eldoret Polytechnic, Kenya, 2013) Nashon, SM.; Anderson, D.; Ooko, S.; Beru, FK.; Okemwa, P.; Ombogo, P.
In this study we examined whether and how youth learned life skills through their involvement on a high school soccer team. We collected data from fieldwork and interviews with 12 male student-athletes and the head coach from one team. Results showed that the coach's philosophy involved building relationships and involving student-athletes in decision making. Issues relating to three life skills (initiative, re spect, and teamwork/leadership) were identified. Although we observed little direct teaching of these life skills, we saw that players generally were producers of their own experiences that supported the development of these skill.
Kenyan students’ resonance with contextualized science: Critical reflections on traditional science curriculum and instruction
(Eldoret Polytechnic, 2013) Nashon, SM.; Anderson, D.; Beru, FK.; Ooko, S.
Despite the centrality of the informal manufacturing sector (Jua Kali) to the Kenyan society and its richness in scientific phenomena, there is no strong link between activities in the Jua Kali and school science. And, although there has been an ongoing public discourse in Kenya to industrialize, this hope is unlikely without connecting classroom science to the real world of the Jua Kali. In view of this concern, an interpretive case study was framed to investigate Kenyan high school students’ views of contextualized science learning in culturally relevant real-world science curriculum. This article reports the analysis of Kenyan students’ views of contextualized science learning and school science curriculum and instruction elicited through an interpretive case study approach employing interview methods. The analysis of interview data reveals that the participating students interviewed expressed views that: (1) acknowledged the richness of Jua Kali in scientific phenomena and embedded science; (2) indicated existence of a lack of meaningfulness and relevance in existing science curriculum and instruction model; (3) revealed experience of resonance of group and real life learning strategies modeled in the curriculum unit with their preferred learning modes; and (4) revealed their metacognitive assessment of the traditionally used and the new contextualized science modeled learning strategies. Thus, this article offers insight about the Kenyan students on their journey through the experience.
Projected rainfall and temperature changes over Bungoma county in western Kenya by the year 2050 based precis modeling system
(Dept. of Geography, Bahir Dar university, 2016) Juma, SG.; Kelonye, F.
This study investigated projected changes in rainfall and temperature over Bungoma County by the year 2050 based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A1B and A2B emission Scenarios (IPCC, 2007) using the Providing Regional Climates for Impacts Studies (PRECIS); (Giorgi, 2007). The PRECIS regional Climate Model (Hadley RM3P) was configured in 0.22°×0.22° horizontal grid resolution was forced at the lateral boundaries by the UKMO-HadAM3P and UKMOHadCM3 global Models. The future projection of temperature indicates warming over Bungoma County by the year 2050 coupled with reduced precipitation. Time series analysis revealed a cyclic and seasonal trend in rainfall and temperature over the area of study. Temporal characteristics revealed a warmer and colder September-OctoberNovember (SON) season under A1B and A2B scenarios respectively. The results also revealed increasing temperatures and reducing rainfall across all seasons under both scenarios except in March-April-May (MAM) season where rainfall amounts increased and temperature reduced. A two paired t-test for the two climate variables revealed a ρ value of less than 0.05 (ρ<0.05) suggesting a statistically significant relationship between each pair of the two variables. The study recommends further evaluation of the model performance in simulating the present day climate over the area of study.
Contextualized science teaching and student performance: The case of a kenyan girls science class
(Instituto de relaciones internacionales daza de valdes, 2017) Ooko, Selline.; Beru, Festus K.; Nashon, Samson M.; Anderson, David.; Namazzi, Elizabeth.
This paper is about a case study that investigated the impact of contextualized science teaching and learning onperformance of a Form three (Grade 11) class in one of Kenya’s girls high schools. The class experienced nine weeks ofcontextualized science learning. This involved a full day visit toJua Kaliwhere they interacted with artisans. ‘‘Jua Kali’’ is asmall-scale manufacturing and technology-based service sector where artisans manufacture equipment and otherhousehold items that are ubiquitous in everyday Kenyan culture. The visit was followed by organized classroom-basedgroup discussions about what they had learnt and considered most relevant and meaningful. Following this highlyengaging student learning discourse, their creativity and innovative abilities in science improved tremendously as reflectedin the quality of class presentations and participation in the National Science Congress. Moreover, the school’sperformance in the Kenya Certificate of Secondary Education (KCSE): a final national exam at the end of Form 4(Grade 12) improved from a mean of 9.3 in the previous year to 10.4 in the intervention year (p = 0.022). This was furtherattributable to significant improvement in all science subjects: biology, chemistry, physics and mathematics. Besides thecritical insights about theJua Kali’srichness in scientific phenomena, there is also great potential for contextualized scienceexperience to enhance students’ deeper understanding of science.
Health implications of heavy metals in soil, scalp hair and selected food crops within Eldoret Municipality, Kenya
(Journal of environmental science, toxicology and food technology, 2013) Ngure, Veronia.; Sitati, Noah.; Shisia, Silvanus.; Simiyu, Gelas.; Kinuthia, Geoffrey.; Kelonye, Festus.
Heavy metals were analyzed in soils, food crops and male scalp hair samples collected from two age group subjects; adults (18 - 45 years) and old age (46 - 55 years) males from polluted and relatively less polluted areas in Eldoret Municipality environs, Kenya. The samples used were collected from same sites as the individuals who had stayed in the sampled regions for more than five years. The samples were digested using acids and analyzed using Atomic Absorbtion Spectrometry (AAS). The results revealed that the consumption of food crops grown on contaminated soils have significantly increased the concentrations of selected metals in the human hair. Pd and Cd concentrations in soils and food crops showed elevated levels above the WHO recommended limits. Pb, Cd, Cr, Cu, and Zn concentrations were significantly higher (p < 0.05) in male scalp hair samples collected from polluted area as compared to control area. In conclusion, consumers in the study area are exposed to high health risks associated with bioaccumulation of heavy metals through ingestion of heavy metals resulting from contamination of food crops grown in the study area and should be sensitized on the dangers of heavy metals on their health.
Student learning impact on science teachers’ teaching: The case of a form 3 science case in Kenya .
(201) Nashon, SM.; Anderson, D.; Okemwa, P.; Kelonye, Festus.; Ooko, Selline.; Ombogo, Peterson.
This paper reports on the study that investigated the following question: How do Kenyan science teachers perceive the impact of students’ contextualized science learning on their pedagogy, roles and Views about previously modeled pedagogy in an integrated classroom-local Jua Kali curriculum unit? A case study approach in which narrative and teacher change were respectively employed as methodological and analytical frameworks revealed that the teachers: 1) gained an increased awareness of and understood better their students’ science learning abilities that allowed them to take increased responsibility for own learning, 2) developed and accepted new understanding of their teaching roles, and 3) became more critical of how science pedagogy was modeled for them as students and continuing practitioners.

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