DR. DUNCAN ONYANGO MBUGE

The groundnut, Arachis hypogaea Linn, samples were collected from the majorly grown areas of western Kenya to investigate the viscoelastic properties pertinent to grain handling, storage and processing. In particular, the study conducted at the University of Nairobi, Department of Environmental and Biosystems laboratories in July 2010, aimed at investigating the stress-strain properties of bulk groundnuts in relation to Maxwell polymer viscoelastic model. The Mohr-Coulomb failure criterion was also applied to bulk groundnuts. Three samples were prepared for triaxial tests; each weighing 1062.4 g. The moisture content of the samples was 7.6%. The sample size for triaxial testing was 100 mm diameter and 199 mm height. Density of the samples during the tests was 678.6 kg/m3. Confining stresses of 200, 400 and 600 kPa were used and Axial Strain Rate (ASR) of 0.5 mm/min was used for the triaxial compression tests. For the senstar universal testing machine relaxation time was about 30 min for each of the samples. Relaxation data was recorded after every 30 sec for the duration of the test (30 min). These results showed that the Maxwell model for viscoelastic polymers can be applied to accurately describe the behaviour of bulk groundnuts.

The main objective of this study was to determine the service life of high-density polyethylene lining when exposed to natural degradation in tropical climates using time-dependant properties. The changes in material density, strength, and strain at fracture over the degradation period were determined. Optical micrographs were obtained to track the changes in the material during aging. An exponential decay equation was developed that estimates of the service life of the high-density polyethylene lining. It was concluded that most of the degradation of the material takes place in the first few months of installation and that both the density and mechanical strength of the material increased in the course of degradation, whereas the fracture strain reduced over time. It was concluded that the most important factor that determines the lifespan of the liner is the ability to maintain high strains. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

isolated from preterm neonates during the outbreak of gastroenteritis in hospital in Nairobi, Kenya, were resistance to trimethoprin-sulfathoxaxole, Chloramphenicol, oxytetracycline and ampicilin, but only a few strains were resistant to cefazolin, cefamandole, cefataximine, amikacin and nalidixic acid. Fourteen different antimicrobial resistance patterns were observed in the 229 strains of E.coli analyzed. Eighty-two percent of the EPEC strains belonged to two resistance patterns. There was no consistent relationship between palsmid profile group and antimicrobial resistance pattern, although one resistance pattern was more frequently observed in EAF-positive strins belonging to the dominant plasmid profile group. Nine percent of the EPEC strins were resistant to gentamicin compared to 37% in the non-EPEC group. No correlation was observed between administration of gentamicin and percentage of resistant strains isolated. None of the nine neonates receiving gentamicin died during the outbreak. Gentamicin resistance was observed in E.coli strains from six out of these nine neonates. Five out of fourteen neonates who received other antimicrobials, or no antibiotic at all, died. Key words: Enteropathogenic Escherichia Coli; antimicrobial resistance;

isolated from preterm neonates during the outbreak of gastroenteritis in hospital in Nairobi, Kenya, were resistance to trimethoprin-sulfathoxaxole, Chloramphenicol, oxytetracycline and ampicilin, but only a few strains were resistant to cefazolin, cefamandole, cefataximine, amikacin and nalidixic acid. Fourteen different antimicrobial resistance patterns were observed in the 229 strains of E.coli analyzed. Eighty-two percent of the EPEC strains belonged to two resistance patterns. There was no consistent relationship between palsmid profile group and antimicrobial resistance pattern, although one resistance pattern was more frequently observed in EAF-positive strins belonging to the dominant plasmid profile group. Nine percent of the EPEC strins were resistant to gentamicin compared to 37% in the non-EPEC group. No correlation was observed between administration of gentamicin and percentage of resistant strains isolated. None of the nine neonates receiving gentamicin died during the outbreak. Gentamicin resistance was observed in E.coli strains from six out of these nine neonates. Five out of fourteen neonates who received other antimicrobials, or no antibiotic at all, died. Key words: Enteropathogenic Escherichia Coli; antimicrobial resistance;

isolated from preterm neonates during the outbreak of gastroenteritis in hospital in Nairobi, Kenya, were resistance to trimethoprin-sulfathoxaxole, Chloramphenicol, oxytetracycline and ampicilin, but only a few strains were resistant to cefazolin, cefamandole, cefataximine, amikacin and nalidixic acid. Fourteen different antimicrobial resistance patterns were observed in the 229 strains of E.coli analyzed. Eighty-two percent of the EPEC strains belonged to two resistance patterns. There was no consistent relationship between palsmid profile group and antimicrobial resistance pattern, although one resistance pattern was more frequently observed in EAF-positive strins belonging to the dominant plasmid profile group. Nine percent of the EPEC strins were resistant to gentamicin compared to 37% in the non-EPEC group. No correlation was observed between administration of gentamicin and percentage of resistant strains isolated. None of the nine neonates receiving gentamicin died during the outbreak. Gentamicin resistance was observed in E.coli strains from six out of these nine neonates. Five out of fourteen neonates who received other antimicrobials, or no antibiotic at all, died. Key words: Enteropathogenic Escherichia Coli; antimicrobial resistance;