Journal Articles

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Hadithi fupi_utanzu uliopuuzwa
(1997) Mohochi, Ernest Sangai
Postharvest moisture loss characteristics of carrot (Daucus carota L.) cultivars during short-term storage
(Elsevier, 1998-02-13) Shibairo, Solomon I.; Toivonen, Peter; Upadhyaya, Mahesh K.
Differences in moisture loss characteristics among carrot cultivars Imperator Special 58, Gold Pak 28, Caro-pride, Paramount, Eagle, Celloking, Top Pak and Caro-choice during short-term storage at 13 °C and at either 80% or 35% relative humidity were investigated. Experiments were conducted over two years with an early and late harvest in each year. Moisture loss was significantly greater when carrots were stored at low relative humidity compared to high relative humidity. Consistent cultivar differences in moisture loss characteristics were observed only in the late-harvested carrots at low relative humidity. Cultivars with higher specific surface area and relative electrolyte leakage, and lower water and osmotic potentials exhibited high moisture losses. Regression analysis, however, showed that moisture loss differences among cultivars were mainly associated with the specific surface area of the root.
On convergence of sections of sequences in Banach spaces
(Springer-Verlag, 2000-02-01) Aywa, Shem; Jan, Fourie
An elementary proof of the (known) fact that each element of the Banach spaceℓ w p (X) of weakly absolutelyp-summable sequences (if 1≤p<∞) in the Banach spaceX is the norm limit of its sections if and only if each element ofℓ w p (X) is a norm null sequence inX, is given. Little modification to this proof leads to a similar result for a family of Orlicz sequence spaces. Some applications to spaces of compact operators on Banach sequence spaces are considered.
On summing multipliers and applications
(Journal of Mathematical Analysis and Applications, 2001-01-01) Aywa, Shem; Jan, Fourie
A scalar sequence (αi) is said to be a p-summing multiplier of a Banach space E, if ∑∞i = 1‖αixi‖p < ∞ for all weakly p-summable sequences in E. We study some important properties of the space mp(E) of all p-summing multipliers of E, consider applications to E-valued operators on the sequence space lp, and extend this work to general “summing multipliers.” The case p = 1 shows close resemblance to the work of B. Marchena and C. Piñeiro (Quaestiones Math., to appear), where the results originated from the authors' interest in sequences in the ranges of vector measures.
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.
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.
Spaces of compact operators and their dual spaces
(Springer-Link, 2004-01-13) Aywa, Shem; Jan, Fourie
Theω′-topology on the spaceL(X, Y) of bounded linear operators from the Banach spaceX into the Banach spaceY is discussed in [10]. Let ℒw' (X, Y) denote the space of allT∈L(X, Y) for which there exists a sequence of compact linear operators (T n)⊂K(X, Y) such thatT=ω′−limnTn and let|||T|||:={supn||Tn||:Tn∈K(X,Y),Tn→w′T}. We show that(Lw′,|||⋅|||) is a Banach ideal of operators and that the continuous dual spaceK(X, Y)* is complemented in(Lw′(X,Y),|||⋅|||)∗. This results in necessary and sufficient conditions forK(X, Y) to be reflexive, whereby the spacesX andY need not satisfy the approximation property. Similar results follow whenX andY are locally convex spaces.
Retrieval of aerosol optical depth over ecologically stressed east African land surfaces from top of atmosphere radiance utilizing the aerosol free vegetation index
(Dept. of Geography, Bahir Dar University, 2005) Makokha, John W.; Angeyo, JW.
Traditional satellite based AOD retrieval techniques with a coarse resolution such as collection 5 hardly provides a high spatial detail suitable for accurate AOD retrieval particularly over the ecologically stressed sites of East Africa. Furthermore, AOD retrievals from Moderate Resolution Imaging Spectroradiometer (MODIS-collection 5) require a linear mixing model that utilizes the normalized difference vegetation index (NDVI) to calculate surface reflectance. Since NDVI is affected by the presence of aerosols in the atmosphere, an empirical linear relationship between short wave infrared (SWIR) and visible reflectance were estimated in order to calculate a modified aerosol free vegetation index (AFRI). Based on AFRI and the minimum reflectance technique (MRT), an improved linear mixing model was developed. Calculated Vis/SWIR ratio diverges from the one used in the hypothetical model for AOD retrieval. Likewise, the regression coefficients between retrieved AOD for the developed algorithm and AERONET were higher as compared to that of MODIS collection 5 and AERONET. These emphasize the need of using AFRI plus accurate selection of surface characteristics and aerosol type for accurate AOD retrieval over East Africa that is addressed by the developed algorithm. At low AERONET AOD values, the two algorithms i.e. MODIS and developed agree but as the AERONET AOD value increases, a discrepancy is noted between the two as a result of usingNDVI and AFRIin the MODIS and developed algorithms respectively.
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
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.
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.
Predicting daily streamflow in ungauged rural catchments: the case of Masinga catchment, Kenya
(Taylor&Francis, 2007) Mutua, Benedict Mwavu; Klik, Andreas
Access to daily streamflow data at the catchment scale, is a central component of many aspects of water resources and water quality management. However, the majority of river reaches in many catchments in Kenya are ungauged or poorly gauged, and in some cases existing measurement networks are declining. Long-term continuous monitoring is not being done due to high costs of equipment maintenance. Therefore, there is a need for an alternative tool such as a catchment-scale hydrological model that is capable of predicting the daily streamflow. An approach is presented of predicting daily streamflow using a physically-based catchment-scale model, the geospatial Stream Flow Model (SFM). The SFM was developed using the “C” programming language and the user interface was developed using the Avenue script of the ArcView software. The SFM simulates the dynamics of runoff processes by utilizing remotely sensed and widely available global or local data sets. The model was applied in the Masinga catchment, Kenya, and the results gave a model performance coefficient of 0.74 based on the Nash-Sutcliffe statistical criterion.
Land use systems and distribution of tichoderma species in Embu region, Kenya
(2007) Okoth, Sheila A.; Roimen, H.; Mutsotso, B.; Muya, Kahindi; Owino, J.O.; Okoth, P.
The distribution of Trichoderma species in soils of Embu region in relation to land use practices was investigated. The study area was chosen because of its significant land use intensification. Soil washing and dilution plate techniques were used to recover Trichoderma spp from soil samples. The fungal isolates were identified and assigned to eight species. Greater populations as well as a wider range of species were obtained in soils collected from the natural forests while coffee farms were the poorest ones. Land use affected the distribution of Trichoderma. Napier farms had the highest abundance of this fungus. The species that showed the highest incidence in all cases was T. harzianum. Plant type was a major determinant of the occurrence of this fungus. Trichoderma favored plants with shallow and widespread rooting systems, to the deeply rooted perennial coffee and tea trees. The age of the plants also was a driving factor. Both inorganic and organic fertilizers are used in the region. There was a negative correlation between amount of chemical fertilizers and abundance of the fungus. Organic fertilizers were used exclusively in napier farms that had the highest fungal abundance. Soil pH and amount of phosphorus were limiting and influenced the occurrence and abundance of this fungus. However carbon and nitrogen were not limiting though they were high in the forests and napier farms where the fungus was also abundant. Trichoderma showed tolerance to soil acidity since it was abundant in the most acidic soils under napier. Land intensification affected Trichoderma distribution negatively.
Exemplary practice and outcome-based mathematics instruction in Kenyan schools/Prácticas ejemplares basadas en resultados de instrucción de las matemáticas en las escuelas de Kenya
(Journal of science education, 2007) Wekesa, Duncan Wasike
The general performance in mathematics among secondary school students in Kenya has over the years been poor. There is evidence that the learning environment is murky and often intractable. This calls for exemplary practice and outcome based instruction where teachers have to create a learning environment in which the learners' capabilities as well as their existing ideas could be effectively used to produce change in the learners' cognitive structures through collaborative social interactions
Efficacy of Tephrosia vogelli and Vernonia amygdalina as anthelmintics against Ascaridia galli in indigenous chicken
(Livestock Research for Rural Development, 2007-01-01) siamba, Donald N.; Watai, M K.; Wachira, A.M.; Lukibisi, F B.; Mukisira, E.A
The efficacy of Tephrosia vogelli and Vernonia amygdalina leaf extracts as anthelmintic against Ascaridia galli was determined in-vitro and in-vivo.The extracts whose chemical constituents included rotenoids, sesquiterpene lactones, glycosides, anthracenes and tannins, had significant (p<0.05) activity against Ascaridia galli both in-vitro and in-vivo. The in-vitro larval migration inhibition of 74.7 and 63.7 % was supported by the faecal egg count reduction of 77.4 and 76.9 and reduced total worm counts at necropsy for Tephrosia vogelli and Vernonia amygdalina extracts, respectively. The results have demonstrated that the extracts of the two plants have significant activity against the chicken parasite Ascaridia galli and can be integrated in indigenous chicken health management system.
Traditional herbal preparations for indigenous poultry health management in Western Kenya
(Livestock Research for Rural Development, 2007-01-01) Okitoi, L O; Ondwasy, H.O.; siamba, Donald N.; Nkurumah, D.
Conventional disease prevention methods are geared towards birds in confinement and not free range in an indigenous poultry production system. However, the existing indigenous technical knowledge inherited from past generations has sustained the local poultry production system. This knowledge is passed on verbally and is hardly documented. The study reportedly collected information on traditional preparations (e.g herbs) in Kimilili and South Wanga of Bungoma and Butere/Mumias districts respectively. Its objective being to document existing plant material (herbs) and any other traditional preparations used for poultry health management in rural poultry production systems. The study confirmed the existence of vast local knowledge for indigenous poultry health management. The preparations are usually more than one-plant parts whose amounts are not specific. They usually target symptoms of diseases, which were encoded into specific diseases. Aloe Vera, pepper, sisal and neem were the most used medicinal plants. Parts used included leaves, barks, and roots. Some specific concoctions were said to prevent or treat specific diseases. For example Aloe Vera was said to treat Newcastle, Croton megalocarpus was said to treat coryza sinusitis, Combretum mole was said to treat intestinal worms.
Access to basic education in Kenya: inherent concerns
(Academic Journals, 2007-10-30) Odebero, Stephen O.; Maiyo, Julius K.; Mualuko, Ndiku J.
Basic education being the minimum education that every Kenyan must have for progressive existence in society is a crucial factor. That is why Kenya subscribes to the international protocol that established Education for All (EFA) in Jomtien, Thailand 1990 and the world education forum in Dakar, Senegal, 2000. Since then, the Kenya Government in her Education Sector Strategic Plan and Sessional paper No. 1 of 2005 has articulated how to attain goals for education. For instance early childhood education which tries to ensure development of the whole personality of the child’s physical, mental, and socioemotional attributes faces challenges such as lack of access to early childhood education mostly caused by poverty, regional and gender disparities, policy framework, and HIV/AIDS among others. At primary school level where children stay longest in the schooling years and they develop more motor skill, further cognitive skills along with higher socialization than the early childhood education level, has children failing to access education due to poverty, gender imbalances, regional imbalances among other concerns. Secondary education which creates a human resource base higher than the primary education along with training youth for further education and the world of work registers restriction to many children due to concerns of poverty, gender imbalances, insecurity regional disparity among others. This article articulates in detail the above concerns discussing their manifestations in Kenya. Conclusions are drawn and recommendations made on how to improve access to basic education in Kenya. Among the recommendations are: To make basic education free and compulsory, improve provision of health services, intensify fight against demeaning cultures, give special attention to children with disabilities, avail employment opportunities to the youth, assure security to all in conflict prone zones and tighten bursary disbursement procedures.
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.
The physico-chemical characteristics and some nutritional values of vegetable amaranth sold in Nairobi-Kenya
(Taylor & Francis, 2008) Onyango, Cecilia M.; Shibairo, Solomon I.; Imungi, Jasper K.; Harbinson, Jeremy
Twenty one major supermarkets and ten independent green grocers in the city of Nairobi were surveyed for types of vegetable amaranths sold and their post harvest handling. The nutrient composition of the vegetables was also analyzed. In addition, information on three other traditional leafy vegetables (TLVs) namely, Cleome gynandra, Solanum nigrum, and Vigna unguiculata was obtained. All the vegetables were sold in bundles of average weight 0.45 kg. The edible fraction per bundle averaged 38.9%. Chemical analys showed that vegetable amaranth had a moisture content of 85.5%, therefore a dry matter content of 14.5%. Expressed on dry matter basis, the mean total ash content was 19.2%, crude protein content 26.1% and the crude fiber content 14.7%. The mean ascorbic acid content was 627 mg/100 g, zinc content 5.5m g/100 g and iron content 18 mg/100 g. The men nitrate content was 732.5 mg/100 g, total oxalates 5830 mg/100 g and soluble oxalates 3650 mg/100 g, while the lead content averaged 1.03 mg/100 g. The study concludes that vegetable amaranth has potential as popular vegetable in the diets of Kenyans to significantly contribute to provision of micronutrients, particularly iron and zinc. KEYWORDS traditional vegetables, marketing, postharvest handling, nutrition, Nairobi-Kenya
Horrifying disasters in western Kenya impact on education and national development
(Academic Journals, 2008-05-07) Achoka, Judith S. K.; Maiyo, Julius K.
The occurrence of natural disasters has shown a positive trend as annual incidents of disaster events have increased on the continent. Approximately two-thirds of the 3.3 million people in Western Kenya fall below the poverty line, leaving the region stuck in poverty traps that prevent sustainable development. Schools in the region are hampered in their operation when the disaster occurs .In third term 2007, many school were unable to open due to flooding, students were transferred to other schools while others dropout of the system. Access to safe water, sanitation, quality education and HIV/AIDS awareness are desperately needed, along with micro-economic development to bring the population up to a livable standard. This study investigates the horrifying disasters in the region and analyzes their impact on education and national development.

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