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Search Results: 1 - 10 of 22 matches for " Koech Florentius "
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Desmoid Tumour of the Brachial Plexus
Orege Juliette,Koech Florentius,Ndiangui Francis,Benson Ndegwa Macharia,Mbaruku Neema
Case Reports in Surgery , 2013, DOI: 10.1155/2013/575982
Abstract: Desmoid tumours of the brachial plexus are rare and may occur in extra-abdominal sites. The tumours are of fibroblastic origin and, although benign, are locally aggressive. Their relationship to critical neurovascular structures in their anatomic locations presents a challenge to the operating surgeons trying to adhere to the principles of surgery. Surprisingly little neurosurgical literature exists which was devoted to this topic despite the challenge these lesions present in surgery both at surgery and in choosing adjuvant therapies. We report a case of a large brachial plexus tumour in a patient which was diagnosed radiologically and histopathologically and the patient underwent surgical excision with good outcome. Desmoid tumours histologically are benign and are usually composed of proliferating, benign fibroblasts in an abundant matrix of collagen. They do not transform into malignant tumours or metastasize. Surgery is the mainstay of treatment; however, adjuvant radiation and chemotherapy remain controversial. 1. Introduction Many terms have been used to refer to desmoids tumours over the years, including fibromatosis, desmoid tumors, and aggressive fibromatosis. However, “Desmoid-type fibromatosis” has emerged as the designation of choice by the World Health Organization [1]. A review of the literature identified three case series reporting the treatment of desmoids tumours involving the brachial plexus. The first series, reported by Binder et al. [2] in June 2004, served to ascertain the rarity of these tumours. Twenty-four patients were treated at the University of California, San Francisco, CA, USA, who had primary brachial plexus tumours and only one (4%) had a desmoid tumour. The second case series reported by Seinfeld et al. [3] in 2006 included four cases of desmoid-type fibromatosis involving the brachial plexus. This series additionally assessed these lesions for mutations in the c-KIT oncogene in hopes of establishing a basis for predicting which of these lesions would respond to the chemotherapy agent imatinib mesylate. In the third case series, Dafford et al. [4] in June 2007 undertook a retrospective study of 15 desmoid tumors in 11 women and four men (ranging in age from 32 to 67 years; median 48 years) treated at their institution. In this study, the results were that there were 13 patients (86%) with brachial plexus lesions. In this review, we document the clinical presentation, neuroimaging, surgical, and pathological findings in a patient with a desmoid tumour arising from the brachial plexus. 1.1. Age and Gender Incidences of
Clinical aplications of Trioxolane derivatives
DK Koech
African Journal of Health Sciences , 2008,
Abstract: The aqueous extracts of three medicinal plants, Carissa edulis (Forssk.) Vahl (Apocynaceae), Prunus africana (Hook.f.) Kalkm (Rosaceae) and Melia azedarach L. (Meliaceae) have shown significant reduction in the replication of human cytomegalovirus (HCMV) in human embryonic lung (HEL) fibroblasts cells in vitro. Using the plaque inhibition assay for the determination of anti-viral activity, the HEL fibroblast cells cultured in 24 well plates were infected with 1 x 102 PFU 91S HCMV and treated with various concentrations of the extracts. The plaques formed were counted after 7 days incubation at 37°C in 5% CO2 and the percent plaques inhibited were calculated against infected untreated control. The effective concentrations inhibiting plaque formation by 50% (EC50) was found between 40 to 80 μg/ml for all the extracts. The cell cytotoxic concentrations (CC50) for each of the three extracts, by the trypan blue exclusion test, gave a safe therapeutic index. These results have demonstrated the potential anti-viral activities of the extracts of the three medicinal plants at non-cytotoxic concentrations African Journal of Health Sciences Vol. 15 (1&2) 2008: pp. 1-5
Knowledge Implementation and Employee Performance Evidence from Kenya.
Dr . Caroline Sitienei Koech
Africa International journal of management education and Governance , 2016, DOI: -
Abstract: Purpose – The purpose of this paper was to examine the interaction effect of employee engagement on the relationship between knowledge implementation and employee performance in Technical Institutions in Kenya. The study therefore, sought to establish the relationship between knowledge implementation and employee performance and the moderating effect of employee engagement on the relationship between knowledge implementation and employee performance. Methodology– The paper adopts regression model and Baron and Kenny approach to test for moderation effects. Findings –The study findings revealed that there is a positive and significant relationship between knowledge implementation and employee performance (β =.083, p<.05). The study further revealed that employee engagement moderates the relationship between knowledge implementation and employee performance (β =-.142, p<.01). Research Limitations/implications– Given that the study looked at knowledge implementation, employee engagement and employee performance at one point in time, longitudinal time span research is recommended to provide more insights on these variables. A longitudinal approach may also help in improving the models ability to make causal statements Theoretical implications - The study contributes to theory by not only examining knowledge attributes but by analyzing empirically the extent of the relationship between knowledge implementation, employee engagement and employee performance. Originality/value – This is the first study that focuses on testing the moderating effect of employee engagement on the relationship between knowledge implementation and employee performance in Technical Institutions in Kenya.
Surface Modification of Hollow Glass Microspheres  [PDF]
Fredrick N. Mutua, Peijie Lin, Jacob K. Koech, Yimin Wang
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.312125
Abstract: Hollow Glass Microspheres are high-strength, low-density additives made from water resistant and chemically-stable soda-lime-borosilicate glass. These hollow glass microspheres offer a variety of advantages over conventional irregularly-shaped mineral fillers or glass fiber. Their spherical shape helps reduce resin content in a variety of applications. They also create a ball bearing effect that can result in higher filler loading and improved flow. In this research, amine terminated hollow glass microspheres were prepared by adopting three different routes. The results were investigated using FT-IR and SEM to establish the formation of amine groups and observe the morphological structure of the modified HGMs. The results obtained were used to select a suitable less toxic and environmental friendly modification method based on the chemicals used.
Application of Hydrazine Hydrate in the Synthesis of Octa(aminophenyl)silsesquioxane (OAPS) Poss  [PDF]
Jacob Kiptanui Koech, Qun Shao, Fredrick Nzioka Mutua, Yimin Wang
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.31011
Abstract:

Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octaphenyl silsesquioxane (OPS) in two steps, first nitration to obtain Octa(nitrophenyl)silsesquioxane (ONPS) then reduction by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent in the presence of Iron(III)Chloride catalyst with a yield of around 87%. Hydrazine is a two-electron reducing agent whereas nitro group is a four-electron reduction process. The activated carbon serves as an adsorbent and electrical conductor enabling the reaction to occur by acting as a mediator between a two-electron reagent and a four-electron process. Adsorption provides a reducing potential and a supply of electrons from many hydrazines making possible the initial four-electron process even though each individual hydrazine is a two-electron donor. The product was characterized by FTIR and 1H NMR. The time period for preparation of ONPS from octaphenyl silsesquioxane was considerably shortened to avoid double nitration of the aromatic rings.

Influence of Land Use Activities on Riparian Vegetation, Soil and Water Quality: An Indicator of Biodiversity Loss, South West Mau Forest, Kenya  [PDF]
Naomi Njue, Eric Koech, Joseph Hitimana, Peter Sirmah
Open Journal of Forestry (OJF) , 2016, DOI: 10.4236/ojf.2016.65030
Abstract: Watershed and riparian areas of Mau Forest Complex in Kenya are experiencing increased threats due to unsustainable land use activities geared towards economic growth amidst growing population. This study was carried out to examine effects of land use activities on riparian vegetation, soil and water quality along two major rivers (Chemosit and Kipsonoi) of South West Mau Forest (SWMF). Land use activities adjacent to these rivers and biodiversity disturbance on the riparian zone were identified and underpinned to changes on Total Nitrogen, Total Phosphorous, Potassium, Sulphur, Cadmium, Copper, Lead, Total Suspended Solids and soil Organic Carbon. Three sampling sites designated(upstream, midstream and downstream) were identified and established along each river as guided by existing land use activities represented by forest, tea plantation and mixed agricultural farming respectively. At each sampling site, a 200 m × 50 m section was systematically marked on each side of the river bank; the longest side being parallel to the river flow and divided into three belts transects each 20 m × 50 m, spaced 70 m apart. Six distinct land use activities (indigenous forest, food crop, tree and tea farming, livestock keeping and urban settlement) were identified as the major land use activities in SWMF. Plant species richness decreased and overall riparian disturbance increased from upstream (intact canopy with native vegetation) to mid-stream and downstream as epitomized by the structure, biodiversity disturbance resulting from extensive and intensive farming, intrusion of exotic species to livestock grazing and urban settlement. Variation among sampling sites in Total Suspended Solids, pH, Total Nitrogen, Phosphorus and Potassium were associated to different land use activities along the riparian zone. Total Nitrogen and water pH showed significant sensitivity to land use changes (p < 0.05). Put together these results indicate loss of biodiversity, riparian disturbance hence a need to adopt environmental-friendly land use planning and sustainable farming systems in SWMF.
Living Off Wetlands: A Case Study of Mara Bay and Masirori Wetlands, Tanzania  [PDF]
David Omolo, Philip Kibet Langat, Richard Koech, Yong Jiang
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.612003
Abstract: This study was undertaken to help highlight the negative impacts of economic activities on wetlands in East Africa with a specific focus on Mara Bay and Masirori wetlands, Tanzania, a region where the local communities still harness wetland resources for economic sustenance. Key economic activities and the negative impacts of the income-generating activities on the wetlands are identified, including the main goods harnessed, level of dependency of the locals to the wetlands, and the level of environmental knowledge of the locals on the wetlands’ ecosystem services. Both qualitative and quantitative tools and techniques viz.: questionnaires, semi-structured interviews, market surveys and spreadsheet analysis were used in this study. The proportion of wetland users involved in papyrus harvesting, food crop cultivation and fishing was 30%, 25% and 24%, respectively while charcoal/firewood and grass for livestock accounted for 12% and 7%, respectively. Significant differences in incomes for charcoal (p < 0.05) across the four villages were recorded but farming, fishing, mat making, herding and fish mongering were non-significant. About 6% of those interviewed had some considerable knowledge on wetland ecosystem services, while the rest (94%) lacked information. Issues identified as having detrimental impacts on the wetlands’ ecosystem services included conversion of sections of the wetlands into farmlands, grazing, charcoal burning, unsustainable fishing, overharvesting of papyrus and brick-making. Farming was found to be a major income-generating activity within the two wetlands. Other important economic activities were charcoal burning, fishing, mat making and fish mongering. The findings from the research are useful for devising appropriate strategies for wetland conservation. Such measures may include assigning wetland ecologists to the village governments, valuation of the wetlands, commissioning of a price and resource regulatory board for the wetland goods, creation of wetlands monitoring program, a fining regime system and a roll-out of mass environmental education in the wetlands regions.
Factors Associated with First-Line Antiretroviral Therapy Failure amongst HIV-Infected African Patients: A Case-Control Study  [PDF]
Charles M. Kwobah, Ann W. Mwangi, Julius K. Koech, Gilbert N. Simiyu, Abraham M. Siika
World Journal of AIDS (WJA) , 2012, DOI: 10.4236/wja.2012.24036
Abstract: Background: Since 2001, anti-retroviral therapy (ART) has been provided to over 75,000 HIV-infected patients at the USAID-Academic Model Providing Access to Healthcare (AMPATH) Partnership in western Kenya. Over 1000 of these patients have switched to second-line ART. We therefore set out to determine factors associated with first-line ART failure amongst these patients. Methods: This case controlled study matched patients (in the ratio 1:2) from the electronic AMPATH Medical Record System on the basis of age, gender, and ART initiation date. Cases were adults (≥18 years) who initiated second-line ART between January 1, 2007 and July 31, 2011 after at least one viral load measurement >5000 copies/ml or satisfying the WHO immunological or clinical failure criteria. Controls were those on non-failing first-line ART with a CD4 count > 400 /ml within the last 12 months, at the time of case incidence. Conditional logistic regression for paired data was used to assess association. We evaluated the strength of association of risk factors using stratified Cox model. Results: Of the 1084 cases and 2149 controls included in the analysis, 62% were female. Median age was 36.5 years (IQR = 30.7 - 43.1); median baseline CD4 cell count was 161 /ml (IQR = 72 - 277); Median time to ART failure was 37 months (IQR = 24 - 47). Low baseline CD4 count < 50 /ml (H.R = 7.07, (95% CI = 4.92 - 10.15); Zidovudine based ART (H.R 1.76, 95% CI = 1.25 - 2.48) and imperfect ART adherence (H.R = 2.77, 95% CI = 2.20 - 3.49) were independently associated with treatment failure. Conclusion: In this setting, low baseline CD4 count, zidovudine-based ART and imperfect adherence are associated with first-line ART treatment failure.
Correlation between Nucleon-Nucleon Interaction, Pairing Energy Gap and Phase Shift for Identical Nucleons in Nuclear Systems  [PDF]
Willy K. Koech, Ken M. Muguro, Godfrey S. Murunga, Kapil M. Khanna
Journal of High Energy Physics, Gravitation and Cosmology (JHEPGC) , 2019, DOI: 10.4236/jhepgc.2019.52018
Abstract: Assuming some known nucleon-nucleon interactions, and using the relations between phase shift δ and nucleon-nucleon interaction potential V (r) ; the relation between nucleon-nucleon interaction and scattering length a; the relation between energy gap Δ, and scattering length a; an equation is obtained between energy gap Δ and Fermi momentum kF via the phase shift δ (kF). Assuming 1s0 (singlet) pairing between the nucleons, the energy gap Δ has been calculated and it is found that Δ = 3.0 MeV at Fermi momentum kF = 0.8 fm-1.
Use of Dry Land Tree Species (Prosopis juliflora) Seed Pods as Supplement Feed for Goats in the Arid and Semi Arid Lands of Kenya
Koech O. Kipchirchir,Kinuthia R. Ngugi,R.G. Wahome
Environmental Research Journal , 2012, DOI: 10.3923/erj.2011.66.73
Abstract: This study was conducted to determine the potential of incorporating Prosopis juliflora seed pods into typical dry land livestock production systems to minimize feed scarcity during the dry seasons and avoiding weight losses and poor performance. The study evaluated supplementation of weaner Galla goats with increasing amounts of Prosopis juliflora seedpods that is widely distributed in arid and semi arid areas of Kenya. This species is drought tolerant and with high productivity of seed pods whole year round. The overall aim of this study was therefore, to assess the feasibility of incorporating P. juliflora seedpods into a typical dry land livestock production system. The study further sought to find out the optimum supplementation level for improved performance. The experiment involved 20 weaner Galla goats of similar age (6 months) and weights (11-14 kg) which were randomly assigned to four treatments of 5 weaners each. The treatments were No P. juliflora (PJP0), 100 g/goat/day P. juliflora (PJP100), 200 g/goat/day P. juliflora (PJP200), 400 g/goat/day P. juliflora (PJP400). Supplementation involved providing the goats with their respective diets in the morning before mixed species range grass hay was offered as basal diet. The animals were weighed on weekly basis and weight gains calculated as difference in previous week s weight and current week s weight. The experiment lasted for 70 days. Overall, all the treatment groups exhibited higher average weekly weight gains than the control group throughout the experimental period. However, for the first 3 weeks, this was not statistically significant (p<0.05). From the 5th week up to the 10th week, there was significant difference (p<0.05) in the growth rates for the treatments except for the control group. Overall, treatment PJP200 exhibited highest total weight gain (3.960c) followed by PJP400 (2.700 kg). Group PJP0 had the lowest weight gain by the end of the experiment. The supplemented groups showed good weight gains, body condition and retained nitrogen levels compared to the un-supplemented groups.
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