Kakamega, Kenya

Masinde Muliro University of Science and Technology, formerly Western University College of Science and Technology, is a public university in Kenya. The university is named after Masinde Muliro, a beloved Kenyan politician who helped found the school. Muliro died in 1992. Wikipedia.

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Serem W.K.,Louisiana State University | Serem W.K.,Masinde Muliro University of Science and Technology | Bett C.K.,University of California at San Diego | Ngunjiri J.N.,NanoInk Inc. | Garno J.C.,Louisiana State University
Microscopy Research and Technique | Year: 2011

Amyloid peptide (Aβ) is the major protein component of plaques found in Alzheimer's disease, and the aggregation of Aβ into oligomeric and fibrillic assemblies has been shown to be an early event of the disease pathway. Visualization of the progressive evolution of nanoscale changes in the morphology of Aβ oligomeric assemblies and amyloid fibrils has been accomplished ex situ using atomic force microscopy (AFM) in ambient conditions. In this report, the size and the shape of amyloid β1-40 fibrils, as well as the secondary organization into aggregate structures were monitored at different intervals over a period of 5 months. Characterizations with tapping-mode AFM serve to minimize the strong adhesive forces between the probe and the sample to prevent damage or displacement of fragile fibrils. The early stages of Aβ growth showed a predominance of spherical seed structures, oligomeric assemblies, and protofibrils; however the size and density of fibrils progressively increased with time. Within a few days of incubation, linear assemblies and fibrils became apparent. Over extended time scales of up to 5 months, the fibrils formed dense ensembles spanning lengths of several microns, which exhibit interesting changes due to self-organization of the fibrils into bundles or tangles. Detailed characterization of the Aβ assembly process at the nanoscale will help elucidate the role of Aβ in the pathology of Alzheimer's disease. Microsc. Res. Tech., 2011. © 2010 Wiley-Liss, Inc.

Sindiku O.,University of Ibadan | Orata F.,Masinde Muliro University of Science and Technology | Weber R.,POPs Environmental Consulting | Osibanjo O.,University of Ibadan
Chemosphere | Year: 2013

Levels of seven major perfluoroalkyl carboxylates (PFCAs) and three perfluoroalkyl sulfonates (PFSAs) were analyzed for the first time in sludge from wastewater treatment plants from Nigeria. Measurements were performed using an analytical methodology using solid-phase extraction (SPE) and ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS-MS). The method detection limit and method quantification limit was 3. pg/g and 9.5. pg/g for both analytes (PFCAs and PFSAs) respectively. Typical recoveries ranged from 50% to 104% for spiked mass labeled internal standards of 1. ng (absolute value) to 1. g of sample. All sludge samples taken from industrial, domestic and hospital wastewater treatment plants contained measurable levels of PFASs. Levels of the quantified perfluoroalkyl carboxylates and perfluoroalkyl sulfonates concentrations ranged from 10 to 597 and 14 to 540. pg/g, respectively. The concentrations were therefore lower compared to sewage sludge samples reported in other regions in the world. Perfluoroalkyl carboxylates with carbon chain having ≥8 fluorinated carbons were detected in the analyzed sewage sludge samples at higher levels compared to carboxylates with <8 fluorinated carbon chain. The measured concentrations indicate that no PFAS point source for the 10 investigated sewage treatment plants existed. Furthermore the low levels in the four municipal sewage treatment plants in Lagos is a first indication that even in an African megacity like Lagos the PFASs release from households are low until now. The highest PFOS level was found in a hospital sewage sludge (539.6. pg/g) possibly indicating (minor) release from medical equipment where some are known to contain PFOS. The PFASs in waste water sludge from a brewery warrant further investigations. © 2013 Elsevier Ltd.

Korir J.C.,Kenya Medical Research Institute | Korir J.C.,Jomo Kenyatta University of Agriculture and Technology | Korir J.C.,Masinde Muliro University of Science and Technology | Magambo J.K.,Jomo Kenyatta University of Agriculture and Technology | And 2 more authors.
Malaria Journal | Year: 2012

Background: Recent studies implicate deficiency of red blood cell (RBC) complement regulatory proteins (CR1 and CD55) in the pathogenesis of malarial anaemia. This study explored the involvement of B cell CD21, which has an analogous role to RBC CR1. Methods. In a case control study conducted in Kisumu District hospital, western Kenya, children with severe malaria anaemia (SMA) and those with uncomplicated malaria (UM) were assessed by flow cytometry for B cells (CD20+) numbers, expression levels of CD21 and deposition of C3dg and by ELISA for soluble CD21 (sCD21). Paired t tests were used to determine statistical significance at a = 0.05. Results: Children with SMA had significantly higher lymphocyte count (9,627.7 ± 8786.1 SD vs. 5,507 ± 2436 SD, P = 0.04 in the UM group) and the computed geometric mean of mature B-cell numbers based on the absolute lymphocyte count was significantly higher for SMA group: 1,823 (1,126 to 2,982, 95% CI) and 826.6 (564 to 1,220, 95% CI)] for UM group (P = 0.003). SMA group also had a higher percentage of CD20+ B cells (26.8 ± 9.7SD vs 20.9 ± 9.01 SD in the UM) (P = 0.03), indicating considerable polyclonal B-cell activation. The CD21 median flourescence intensity was lower in the SMA (246.4 ± 87.4 SD vs 369 ± 137.7 SD) (P < 0.0001), probably due to complement mediated shaving of CD21 by fixed tissue macrophages. The CD20+ B cells of SMAs had higher levels of the complement split product C3dg (18.35 ± 10 SD vs 11.5 ± 6.8 S.D), (P = 0.0002), confirming possible role of complement in CD21 removal. Unexpectedly, the SMAs had lower levels of sCD21 (226.5 ± 131.5 SD vs 341.4 ± 137.3 SD in the UM) (P < 0.0001), indicating that the shaved CD21 is not released to peripheral circulation. Conclusions: These results implicate B-cell in pathophysiology of severe malaria that involves increased B-cell proliferation, increased complement deposition and subsequent loss of membrane-bound CD21. The loss of CD21 is not by the classical enzmatic cleavage. © 2012 Korir et al; licensee BioMed Central Ltd.

Garcia-Pardo C.,Technical University of Cartagena | Molina-Garcia-Pardo J.-M.,Technical University of Cartagena | Garrido-Cervantes A.,Technical University of Cartagena | Muhehe J.D.,Masinde Muliro University of Science and Technology | Juan-Llacer L.,Technical University of Cartagena
IEEE Transactions on Antennas and Propagation | Year: 2012

The ultrawideband (UWB) propagation channel is analyzed by means of measurements carried out in the 2-5 GHz frequency band in an office environment for different scenarios. Measurements were performed for different polarizations on the transmitting and receiving arrays so the effect of the signal polarization can be also taken into account in the analysis. The main contribution of this paper is not only the analysis of path loss and RMS delay spread in a bandwidth of 3 GHz, but also the influence of frequency on such parameters. The relationship between the path loss for copolar configurations and the cross-polarization discrimination (XPD), both in space and frequency domain, is also addressed. © 2012 IEEE.

Olofintoye O.,University Of Ilorin | Otieno F.,Masinde Muliro University of Science and Technology | Adeyemo J.,Durban University of Technology
Applied Soft Computing Journal | Year: 2016

The adverse effects of power shortages resulting from escalating energy demands, due to rapid global urbanization and industrial developments, have driven efforts worldwide in search for improved techniques for sustainable reservoir operations and optimization for hydropower generation. Recent studies have shown that, combining accurate reservoir inflow forecasting procedures with efficient optimization techniques can produce more efficient and balanced solutions, for operation of multipurpose reservoir systems to improve on the economy of hydropower production. This study presents the coupling of a data driven artificial neural network (ANN) model and a novel combined Pareto multi-objective differential evolution (CPMDE), for hydrological simulation and multi-objective numerical optimization of hydropower production, from the Vanderkloof dam in real-time. Results from the application of the real-time strategy, indicate a significant improvement in performance over the current practice. Therefore, the hybrid ANN-CPMDE real-time reservoir operation model suggested herein provides a low cost solution methodology, suitable for sustainable operation of the Vanderkloof reservoir in South Africa. © 2016 Elsevier B.V.

Ngigi A.N.,Masinde Muliro University of Science and Technology | Getenga Z.M.,Masinde Muliro University of Science and Technology | Boga H.I.,University of Nairobi | Ndalut P.K.,Moi University
Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes | Year: 2012

In this study soils from sugarcane-cultivated fields were screened for bacterial species capable of atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) degradation due to long exposure of the soils to this herbicide. To enrich for atrazine degraders, Minimal Salt Medium containing atrazine as the sole N source and glucose as the C source was inoculated with soils impacted with this herbicide and incubated. Bacterial growth was monitored by measuring optical density. The degradation of atrazine was followed by measuring residual atrazine in liquid cultures over a given time period by high performance liquid chromatography. Bacterial strains isolated from the enrichment cultures were characterized by biochemical tests and identified by 16S rRNA gene sequencing. Two bacterial strains coded ISL 8 and ISL 15 isolated from two different fields were shown to have 94 and 96% 16S rRNA gene sequence similarity to Burkholderia cepacia respectively. Another bacterial sp., ISL 14 was closely related to Enterobacter cloacae with a 96% 16S rRNA gene sequence similarity. There was not much difference between the extents of atrazine degradation by the enrichment cultures with communities (79-82% applied amount) from which pure strains were isolated and the pure strains themselves in liquid cultures that showed a degradation of 53-83% of applied amount. The study showed existence of bacterial strains in different sugarcane-cultivated fields which can use atrazine as a nitrogen source. The bacterial strains isolated can be used to enhance the degradation of atrazine in contaminated soils where atrazine is still considered to be recalcitrant. © 2012 Taylor and Francis Group, LLC.

Vestergren R.,University of Stockholm | Orata F.,University of Stockholm | Orata F.,Masinde Muliro University of Science and Technology | Berger U.,University of Stockholm | Cousins I.T.,University of Stockholm
Environmental Science and Pollution Research | Year: 2013

Beef and dairy products may be important vectors of human exposure to perfluoroalkyl acids (PFAAs), but the understanding of how PFAAs are accumulated and transferred through agricultural food chains is very limited. Here, the bioaccumulation of PFAAs in dairy cows receiving naturally contaminated feed and drinking water was investigated by conducting a mass balance of PFAAs for a herd of dairy cows in a barn on a typical Swedish dairy farm. It was assumed that the cows were able to reach steady state with their dietary intake of PFAAs. Perfluorooctane sulfonic acid (PFOS) and perfluoroalkyl carboxylic acids (PFCAs) with 8 to 12 carbons were detected in cow tissue samples (liver, muscle, and blood) at concentrations up to 130 ng kg-1. Mass balance calculations demonstrated an agreement between total intake and excretion within a factor of 1.5 and consumption of silage was identified as the dominant intake pathway for all PFAAs. Biomagnification factors (BMFs) were highly tissue and homologue specific. While BMFs of PFOS and PFCAs with 9 and 10 fluorinated carbons in liver ranged from 10 to 20, perfluorooctanoic acid (PFOA) was not biomagnified (BMF < 1) in any of the investigated tissues. Biotransfer factors (BTFs; defined as the concentration in tissue divided by the total daily intake) were calculated for muscle and milk. Log BTFs ranged from -1.95 to -1.15 day kg-1 with the highest BTF observed for PFOS in muscle. Overall, the results of this study suggest that long-chain PFAAs have a relatively high potential for transfer to milk and beef from the diet of dairy cows. However, a low input of PFAAs to terrestrial systems via atmospheric deposition and low bioavailability of PFAAs in soil limits the amount of PFAAs that enter terrestrial agricultural food chains in background contaminated environments and makes this pathway less important than aquatic exposure pathways. The BTFs estimated here provide a useful tool for predicting human exposure to PFAAs via milk and beef under different contamination scenarios. © 2013 Springer-Verlag Berlin Heidelberg.

Ombori O.,Kenyatta University | Muoma J.V.O.,Masinde Muliro University of Science and Technology | Machuka J.,Kenyatta University
Plant Cell, Tissue and Organ Culture | Year: 2013

The study was carried out to evaluate the amenability of tropical inbred and hybrid maize lines, using Agrobacterium mediated transformation technique. Agrobacteriumtumefaciens strains EHA101 harbouring a pTF102 binary vector, EHA101, AGL1, and LBA4404 harbouring pBECK2000. 4 plasmid, LBA4404, GV and EHA105 harbouring pCAMBIA2301 plasmid, and AGL1 harbouring the pSB223 plasmid were used. Delivery of transgenes into plant tissues was assessed using transient β-glucuronidase (gus) activity on the 3rd and 4th day of co-cultivation of the infected Immature Zygotic Embryos (IZEs) and embryogenic callus. Transient gus expression was influenced by the co-cultivation period, maize genotype and Agrobacterium strain. The expression was highest after the 3rd day of co-culture compared to the 4th day with intense blue staining was detected for IZEs which were infected with Agrobacterium strains EHA105 harbouring pCAMBIA2301 and EHA101 harbouring pTF102 vector. Putative transformants (To) were regenerated from bialaphos resistant callus. Differences were detected on the number of putative transformants regenerated among the maize lines. Polymerase chain reaction (PCR) amplification of Phosphinothricin acetyltransferase (bar) and gus gene confirmed the transfer of the transgenes into the maize cells. Southern blot hybridization confirmed stable integration of gus into PTL02 maize genome and segregation analysis confirmed the inheritance of the gus. A transformation efficiency of 1. 4 % was achieved. This transformation system can be used to introduce genes of interest into tropical maize lines for genetic improvement. © 2012 Springer Science+Business Media Dordrecht.

Dinda V.,Masinde Muliro University of Science and Technology
Ethiopian journal of health sciences | Year: 2013

In low income countries, surgical site infections (SSIs) are costly and impose a heavy and potentially preventable burden on both patients and healthcare providers. This study aimed to determine the occurrence of SSI, pathogens associated with SSI, the antibiogram of the causative pathogens and specific risk factors associated with SSI at the hospital. Two hundred and sixty-eight respondents admitted for general surgical procedures (other than neurological and cardiothoracic surgeries) at the Aga Khan University Hospital were eligible to take part in the study. Post-surgery patients were observed for symptoms of infection. Follow ups were done through the consulting clinics, breast clinic and casualty dressing clinic by a team of surgeons. In cases of infection, pus swabs were collected for culture. SSI incidence rate was 7.0%, pathogens isolated from SSI included gram negative enteric bacilli and S. aureus which was the most prevalent bacterial isolate. Only one isolate of MRSA was found and all staphylococci were susceptible to Vancomycin. Preoperative stay ≥ 2 days and wound class were the risk factors associated with SSI. The SSI incidence rates (7.0%) observed in this study were relatively lower than the ones documented in other studies in Kenya. S. aureus is the most prevalent pathogen associated with SSI. Similar to findings from other studies done in the region; prolonged hospital stay and dirty wounds were the risks associated with postsurgical sepsis at the hospital.

Dinda V.,Masinde Muliro University of Science and Technology | Kimang'a A.,Kenyatta University
African Health Sciences | Year: 2016

Introduction: Overwhelming evidence implicates Helicobacter pylori (H. pylori) as an etiologic agent of gastrointestinal diseases including gastric cancer. The mode of transmission of this pathogen remains poorly understood. Objective: This investigation is to establish the presence of H. pylori in the waters of the Nairobi river basin and the predictive value the presence of fecal indicator bacteria would have for H. pylori. Methodology: Physical, chemical and biological assessment of water quality of rivers in Nairobi were carried out using standard methods. H. pylori DNA in water was detected using highly specific primers of glmM gene (294pb). Results: There was high presence of faecal bacteria in the waters sampled. H. pylori DNA was detected in two domestic wells and one river. The wells were located in two different regions of the water basin but influenced by similar human activities. Conclusion: The high presence of faecal bacteria in the waters sampled did not parallel the H. pylori detection in the same waters. H. pylori was detected in the Nairobi river basin, but there was no relationship between the numerical levels of fecal bacteria and H. pylori. © 2016, Makerere University, Medical School. All rights reserved.

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