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Item Suppression of interfering ions in the analysis of plants to determine fluoride using the fluoride ion selective electrode(Royal Society of Chemistry, 197) Brian, Vickery; Vickery, M. L.Plant ashes may contain sufficient aluminium and/or iron to interfere seriously in the determination of fluoride ions when using the fluoride ion selective electrode. In the presence of these metals the known additions method gave erroneous results, as did that involving the attempted formation of complexes with ethylenediaminetetraacetic acid, disodium salt, or 1,2-cyclohexylenedinitrilotetraacetic acid. Good recoveries of fluoride ion were obtained in the presence of aluminium, iron, magnesium or silicate, using sodium citrate as the complexing agent. The application of the citrate complex method to ashes of commercial tea, high in aluminium and iron, gave recoveries of fluoride ion of greater than 90%.Item Characterization of heart plaque in by‐passed and non‐bypassed heart arteries(Taylor & Francis, 199) Murungi, J. I.; Robinson, J. W.Patients who have undergone bypass surgery often find the bypasses fill up again with plaque ("new plaque") whereas the heart arteries not bypassed contain plaque deposited since childhood ("old plaque"). A preliminary study was undertaken to characterize and contrast the chemical compositions of these “new”; and “old”; plaques. The samples were obtained from a particular surgeon. His patients had had bypass surgery but the bypasses had refilled over a period of a few years. In the surgery both bypassed and non‐bypassed arteries were reopened as necessary to improve circulation by surgically drilling out some plaque. This plaque was analyzed. Each particular sample was divided into two portions. One portion was used for lipid analysis using High Pressure Liquid Chromatography (HPLC) and Thin Layer Chromatography (TLC) while the other portion was used for the determination of selected metals using Inductively Coupled Plasma (ICP). The results are summarized below. The analytical procedures (HPLC and ICP) were fast and reliable techniques for plaque characterization and provided extensive information. Phospholipids, lipids, and triglycerides were found in the plaque but the types of phospholipids, lipids and triglycerides varied from one patient to the next. Cholesterol and/or cholesterol esters such as oleate, linoleate and arachidonate were found in both old and newly deposited plaque but not all samples contained cholesterol. The results of metal analyses indicated there was increased deposition of Cu, Zn, Mn, Ca, Mg and P in the newly deposited plaque compared to the old plaque, but Na, Cr, Fe and K decreased in concentration in the new material. The concentrations of calcium and phosphorus were almost sixteen times higher in the new plaque compared to the old deposits. Ca/Mg and Ca/Na ratios was much higher in the new material than the old plaque and the ratio in both the old and the new was much higher than in normal blood. For example the average Ca/Mg ratio in the new plaque was found to be about 77/1 while in the old plaque it was found to be 28/1 in matched samples. The normal ratio in the blood plasma is around 3/1. The Cu/Zn ratios were less than 1/1 in all samples. The ratio in the new material was lower than in the old. Results suggest a change in body metabolism in later life leading to the formation of a different plaque from that deposited in earlier life.Item Contribution of hot spring cyanobacteria to the mysterious deaths of Lesser Flamingos at Lake Bogoria, Kenya(Oxford University Press, 200-03-01) Krienitz, L; Ballot, A.; Kotut, K.; Wiegand, C.; Pütz, S.; Metcalf, J. S.; Codd, G. A.; Pflugmacher, S.Cyanobacterial mats at hot springs on the shore of the alkaline Lake Bogoria, Kenya, were investigated regarding species community and cyanobacterial toxin content. The hepatotoxins microcystin-LR, -RR, -LF and -YR, and the neurotoxin anatoxin-a were present. The mats were dominated by Phormidium terebriformis, Oscillatoria willei, Spirulina subsalsa and Synechococcus bigranulatus. The concentration of microcystins in mat samples, ranged from 221 to 845 μg microcystin-LR equivalents g−1 DW of mat. Anatoxin-a concentrations ranged from 10 to 18 μg g−1 DW of mat. A contribution of the cyanobacterial toxins from the hot spring mats to the mass mortalities of Lesser Flamingos is suggested by: (a), the presence of hot spring cyanobacterial cells and cell fragments, and high concentrations of the cyanobacterial hepato- and neurotoxins in flamingo stomach contents and faecal pellets; (b), observations of neurological signs of bird poisoning at the lake. Cyanobacterial toxins in stomach contents, intestine and fecal pellets were 0.196 μg g−1 fresh weight (FW) for the microcystins and 4.34 μg g−1 FW for anatoxin-a. Intoxication with cyanobacterial toxins could occur by uptake of detached cyanobacterial cells from the mats, as the flamingos need to drink fresh or brackish water, and to wash their feathers daily, which they do in the vicinity of the hot springs, where salinity is lower than in the main body of water of the lake.Item Fabrication of Rh-doped TiO2 nanofibers for Visible Light Degradation of Rhodamine B(Materials Research Society: Volume 1352,, 201) Obuya, E. A.The synthesis and application of environmentally benign, efficient and low cost heterogeneous catalysts is increasingly important for affordable and clean chemical technologies. Nanomaterials have been proposed to have new and exciting properties relative to their bulk counterparts due to the quantum level interactions that exist at nanoscale. These materials also offer enormous surface to volume ratios that would be invaluable in heterogeneous catalysis. Recent studies point at titanium dioxide nanomaterials as having strong potential to be applied in heterogeneous photocatalysis for environmental remediation and pollution control. This work reports the use of surface modified anatase TiO2 nanofibers with rhodium (Rh) nanoparticles in the photodegradation of rhodamine B (RH-B), an organic pollutant. The dimensions of TiO2 nanofibers were 150±50 nm in diameter and the size of the Rh nanoparticles was ~5 nm. The Rh-doped TiO2 catalyst exhibited an enhanced photocatalytic activity in photodegradation of rhodamine B under visible light irradiation, with 95 % degradation within 180 minutes reaction time. Undoped TiO2 did not show any notable phocatalytic activity under visible light.Item Anti-protozoal activity of aporphine and protoberberine alkaloids from Annickia kummeriae (Engl. & Diels) Setten & Maas (Annonaceae)"(BMC Complementary and Alternative Medicine, 201) Malebo, H. M.; Wenzler, Tanja; Cal, Monical; Swaleh, Sauda M.; Omolo, Maurice O; Hassanali, Ahmed; Séquin, Urs; Häussinger, Daniel; Dalsgaard, P.; Hamburger, Matthias; Brun, Reto; Ndiege, I. O.Background: Malaria, trypanosomiasis and leishmaniasis have an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armory of drugs for the treatment of malaria, trypanosomiasis and leishmaniasis. This underscores the continuing need for the discovery and development of new anti-protozoal drugs. Consequently, there is an urgent need for research aimed at the discovery and development of new effective and safe anti-plasmodial, anti-trypanosomal and anti-leishmanial drugs. Methods: Bioassay-guided chromatographic fractionation was employed for the isolation and purification of antiprotozoal alkaloids. Results: The methanol extract from the leaves of Annickia kummeriae from Tanzania exhibited a strong anti-plasmodial activity against the multi-drug resistant Plasmodium falciparum K1 strain (IC50 0.12 ± 0.01 µg/ml, selectivity index (SI) of 250, moderate activity against Trypanosoma brucei rhodesiense STIB 900 strain (IC50 2.50 ± 0.19 µg/ml, SI 12) and mild activity against Leishmania donovani axenic MHOM-ET-67/82 strain (IC50 9.25 ± 0.54 µg/ml, SI 3.2). Bioassay-guided chromatographic fractionation led to the isolation of four pure alkaloids, lysicamine (1), trivalvone (2), palmatine (3), jatrorrhizine (4) and two sets of mixtures of jatrorrhizine (4) with columbamine (5) and palmatine (3) with (-)-tetrahydropalmatine (6). The alkaloids showed low cytotoxicity activity (CC50 30 - >90 µg/ml), strong to moderate anti-plasmodial activity (IC50 0.08 ± 0.001 - 2.4 ± 0.642 µg/ml, SI 1.5-1,154), moderate to weak anti-trypanosomal (IC50 2.80 ± 0.001 - 14.3 ± 0.001 µg/ml, SI 2.3-28.1) and anti-leishmanial activity IC50 2.7 ± 0.001 - 20.4 ± 0.003 µg/ml, SI 1.7-15.6). Conclusion: The strong anti-plasmodial activity makes these alkaloids good lead structures for drug development programs.Item Factors Affecting Stem Borer Parasitoid Species Diversity and Parasitism in Cultivated and Natural Habitats(Entomological Society of America, 201) Kairu, E. W.; Mailafiya, D. M.; Le Ru, B. P.; Calatayud, P.; Dupas, S.The effects of biotic and abiotic factors on stem borer parasitoid diversity, abundance, and parasitism were studied in cultivated and natural habitats in four agroecological zones in Kenya. Comparing habitat types, we found partial support for the “natural enemy” hypothesis, whereby, across all localities, parasitoid diversity was higher in more diverse host plant communities in natural habitats, whereas parasitoid abundance was higher in cultivated habitats. For both habitats, parasitoid richness was mainly influenced by stem borer density and/or its interaction with stem borer richness, whereas parasitoid abundance was mainly affected by stem borer abundance. Parasitoid richness was higher in localities (with bimodal rainfall distribution) with increased spatial and temporal availability of host plants that harbored the borers. Across seasons, parasitoid richness was lower in both cultivated and natural habitats in the driest locality, Mtito Andei. Overall, parasitoid diversity was low in Suam and Mtito Andei, where maize cultivation was practiced on a commercial scale and intense grazing activities persist across seasons, respectively. Across localities, habitats, and seasons, stem borer parasitism was positively correlated with parasitoid richness and abundance. Furthermore, the interaction of rainfall and altitude influenced the presence and absence of parasitoids, and consequently, stem borer parasitism. Parasitism was positively and negatively correlated with temperature in cultivated and natural habitats, respectively. Overall, natural habitats seem to serve as important refugia for sustaining parasitoid diversity, which in turn can affect stem borer parasitism in the cereal cropping system.Item Parasitization of Helicoverpa armigera (Lepidoptera: Noctuidae) by four Indigenous Trichogrammatid Species/Strains in a Mixed Cropping System of Tomato and Okra(SCIENCEDOMAIN international, 201-02-21) Mueke, J. M.; Kalyebi, A.; Hassan, S.; Sithanantham, S.Aims: Egg parasitoids, Trichogramma are recognised as natural enemies of many lepidoptera pests worldwide. In Kenya, a number of indigenous parasitoids species have been recovered. We evaluated the relative preference (parasitism) by four Trichogrammatid egg parasitoid species/strains, namely, T. sp. nr. mwanzai (L), T. sp. nr. lutea (H), T. sp. nr. mwanzai (M) and T. sp. nr. lutea (M) for the African bollworm Helicoverpa armigera on two of its host plants, tomato and okra usually intercropped in smallholder farms in Kenya. Study Design: Host parasitism on host plants. Methodology: Evaluations of parasitism for H. armigera by Trichogrammatid species/strains on Tomato and Okra in bioassays in both laboratory and field cages, in choice and no-choice conditions were undertaken. Results: In general, species/strains exhibited significant differences in parasitism for the host (F=2.8; df =3, 7; P= 0.05) but neither the host plant nor host plant x species/strain interaction affected parasitism. Chi-square analyses showed no significant preference by species/strains between the two host plants although there was greater tendency by the parasitoids to go for H. armigera on okra than tomato. Conclusion: The results give useful insights in planning for augmentation biological control of H. armigera in mixed farming agroecosystems. The four Trichogrammatids could effectively be used in augmentation programs in the tomato-okra cropping systems.Item Prevalence of Metabolic Syndrome Among an Urban Population in Kenya(Diabetes Care, 201-04) Kenya, E.U.; Kaduka, L.U.; Kombe, Y.; Kuria, E.; Bore, J. K.; Bukania, Z. N.; Mwangi, M.OBJECTIVE Developing countries are undergoing an epidemiologic transition accompanied by increasing burden of cardiovascular disease (CVD) linked to urbanization and lifestyle modifications. Metabolic syndrome is a cluster of CVD risk factors whose extent in Kenya remains unknown. The aim of this study was to determine the prevalence of metabolic syndrome and factors associated with its occurrence among an urban population in Kenya. RESEARCH DESIGN AND METHODS This was a household cross-sectional survey comprising 539 adults (aged ≥18 years) living in Nairobi, drawn from 30 clusters across five socioeconomic classes. Measurements included waist circumference, HDL cholesterol, triacylglycerides (TAGs), fasting glucose, and blood pressure. RESULTS The prevalence of metabolic syndrome was 34.6% and was higher in women than in men (40.2 vs. 29%; P < 0.001). The most frequently observed features were raised blood pressure, a higher waist circumference, and low HDL cholesterol (men: 96.2, 80.8, and 80%; women: 89.8, 97.2, and 96.3%, respectively), whereas raised fasting glucose and TAGs were observed less frequently (men: 26.9 and 63.3%; women: 26.9 and 30.6%, respectively). The main factors associated with the presence of metabolic syndrome were increasing age, socioeconomic status, and education. CONCLUSIONS Metabolic syndrome is prevalent in this urban population, especially among women, but the incidence of individual factors suggests that poor glycemic control is not the major contributor. Longitudinal studies are required to establish true causes of metabolic syndrome in Kenya. The Kenyan government needs to create awareness, develop prevention strategies, and strengthen the health care system to accommodate screening and management of CVDs.Item Lead contamination of traditional hand-dug wells in parts of Kwale County, Kenya(International Journal of Physical Sciences, 201-05) Chege, M. W.; Hashim, N. O.; Merenga, Abdullah S.; Tschiersch, J.People’s health, behavior and intellect to a certain extent are a function of their environment. One important component of this environment is water, a basic necessity that human beings cannot do without. The water available, however, is not always safe for human consumption due to contamination. Among the many water contaminants, lead (Pb) is one of the most dangerous due to its bio-accumulative nature and high toxicity. Children are most vulnerable to Pb toxicity as their main organs such as the brain and the nervous system are still developing. For them, exposure to even relatively low concentrations can result in reduced intelligence quotient (IQ), learning disabilities and attention deficit disorders, behavioral problems such as delinquency and drug abuse, and such conditions as impaired hearing and mental retardation. The main aim of the present study was to determine Pb concentration in water from hand-dug wells in Kwale County in the coastal region of Kenya. Kwale County hosts a number of schools for mentally disabled and hearing impaired persons, while the coastal region in general has among the lowest literacy levels in the country and the highest incidences of drug abuse. Thirty-seven water samples were randomly collected from selected villages and analyzed for Pb content using a flame atomic absorption spectrophotometer (FAAS). Also analyzed were the water pH and conductivity using portable digital meters. Pb concentration in the water samples ranged from below detection limit to 1.397 mg/L with a mean concentration of 0.330 mg/L. Over 62% of the samples had Pb levels above WHO recommended value of 0.01 mg/L. The pH ranged from 5.8 to 10.4 with a mean value of 9.2 while conductivity ranged from 85.3 to 6060 μs/cm with a mean value of 930.351 μs/cm. Key words: Lead, well water, intelligence quotient (IQ), mental retardation, deafness, KwaleItem Reactions of Lead Tetraacetate. I. Formation of Acylamines from Primary Carboxamides(CSIRO Publishing, 1968) Hassanali, Ahmed; Acot, B.; Beckwit, A. L. J.Pentanamide, when treated with lead tetraacetate in hot benzene, affords a mixture of N-butylacetamide and N,N?-dibutylurea. Examples of similar transformations of a number of primary carboxamides are described. The reaction, which may also be conducted in acetic acid or benzene-acetic acid mixture, is catalysed by pyridine. Cyclohexanecarboxamide, when oxidized by lead tetraacetate in the presence of propionic or benzoic acid, is converted into the appropriate acylcyclohexylamine. The reaction mechanism involves intermediate formation of alkyl isocyanate, possibly via Curtius rearrangement of acylnitrene.Item Reactions of Lead Tetraacetate. II. Formation of Carbamic Acid Esters from Primary Carboxamides(CSIRO Publishing, 1968) Hassanali, Ahmed; Acott, B.; Beckwith, A. L. J.Treatment of primary carboxamides with lead tetraacetate in benzene-alcohol mixtures or neat alcohol affords a convenient, flexible, and efficient method for the preparation of N-substituted carbamic acid esters. The reaction is applicable to amides and alcohols of a wide range of structural types including compounds containing oleflnic, ester, aromatic, and other reactive functions. The reaction mechanism appears to involve intermediate formation of isocyanates.Item Correlation of melting temperature and cesium chloride buoyant density of bacterial deoxyribonucleic acid.(American Society for Microbiology, 1970) Igambi, L.; Mandel, M.; Bergendahl, J.; Dodson, M. L. Jr.; Scheltgen, E.Samples of bacterial deoxyribonucleic acid from bacteria having guanine plus cytosine (GC) contents in the range of 27 to 72 moles per cent GC were analyzed by optical melting (T(m)) and equilibrium buoyant density methods. The relation between these properties is shown to be linear. The relative value of 1.99 moles per cent GC per degree C change in T(m) is calculated, and a reference method for the calculation of GC contents relative to a standard is derived.Item The Structure and Synthesis of Barakol: a Novel Dioxaphenalene Derivative from Cassia siamea(Royal Society of Chemistry, 1970) Hassanali, Ahmed; Bycroft, B. W.; Johnson, A. W.; King, T. J.Barakol, from the leaves of Cassia siamea, is shown to be a novel dioxaphenalene derivative. A synthesis from 3,5-dihydroxyphenylacetic acid is described.Item The method of the false transient for the solution of coupled elliptic equations(Elsevier, 1973-08-04) Gatheri, F. K.A method for the numerical solution of a system of coupled, nonlinear elliptic partial differential equations is described, and the application of the method to the equations governing steady, laminar natural convection is presented. The essential feature of the method is the conversion of the equations to a parabolic form by the addition of false time derivatives, thus, enabling a marching solution, equivalent to a single iterative procedure, to be used. The method is evaluated by applying it to a well known two-dimensional problem and some examples of its use in three dimensions are given.Item Some effects of mound-building termites on soils in Uganda(Bioinfo Publications, 1976-09) Pomeroy, D. E.Most large mounds in Uganda are built by termites of the genus Macrotermes. Except for those in valley bottoms they are composed of subsoil which is thought to be collected mainly from depths of 0.5 to 1.0 m, although the evidence is inconclusive. Mounds of both M. bellicosus and M. subhyalinus contain less sand than the subsoil when this is sandy, but only M. subhyalinus mounds contain less clay when the subsoil has a high clay content. In general both species tend to produce a stone-free topsoil whose physical properties are closer to a loam than the average subsoil. Mounds of both species in valley bottoms appear to be built from topsoil. The amounts of organic matter, nitrogen, calcium, phosphorus, and potassium in mounds were estimated together with their rates of turnover. In terms of the demands of two typical crop plants the quantities held in mounds and their rate of release to the surrounding topsoil were small. Only calcium was likely to be cycled in significant amounts. It seems that termites only slightly affect the physical and chemical properties of Ugandan soils, even where mounds are comparatively abundant.Item Effects of temperature on growth in the regenerating tail of the scincid lizard, Mabuya striata(Zoological Society of Southern Africa, 1977) Magon, D.K.Experiments on effects of temperature on growth in the regenerating tail of Mabuya striata, artificially autotomized, suggest a faster rate of regeneration during hot weather than cold weather. limbs of newts and salamanders can generally be replaced both in adults and larvae. Amongst reptiles, however, regeneration of limbs is not a common phenomenon. In lizards, for example, limb regeneration occurs only as abnormal outgrowths (Goss 1969). A few lizards are known to restore lost tails, and there generated tail is almost a true substitute for the original tail, not only with respect to structure and function, but also to size. The period taken by a regenerating tail to achieve its original length varies from species to species as well as individual to individual. Such variation in the rate of growth of regenerates seems to be correlated with several factors, viz. the amount of tail autotomized, pressure applied at the time of autotomy, temperature, humidity, hormonal levels and diet (Moffat & BeUairs 1964; Bryant & Bellairs 1967; licht 1967; Maderson & licht 1968; Shah & Chakko 1968; Baiinsky 1970; Magon 197580 1975b). Much more experimentation will be necessary, however, before the effects of these factors can be quantified. The experiments described in this paper examine the influence of temperature on the growth in the regenerating tail ofthe scincid lizard, Mabuya striata, during the different seasons of the year, viz. hot season: December - February; rainy season: March - May & September - November; and cold season: June - August.Item Histological observations on the changes in thyroid activity in the scincid lizard, Mabuya striata, during different phases of tail regeneration(Zoological Society of Southern Africa, 1977) Magon, D.K.Measurements of the follicle cells of the thyroid during different phases of regeneration of the tail in the scincid lizard. Mabuya striata. indicate a decrease in thyroid activity during the wound-healing phase and an increase at the end of the blastema phase. The significance of endocrine secretion of the thyroid has drawn the attention of a number of developmental biologists as the hormone thyroxine brings about various physiological changes during anuran metamorphosis. The regenerative power of these amphibians gradually diminishes as metamorphosis advances. It may be absent in the fully metamorphosed animals (Rose 1964), or sometimes restricted to wound healing or to the formation of a hypermorphic cartiJaginous spike (Richards et oJ. 1975). Further, PawlowskJ (1933), Peadorr (1953) and Schotte & Washburn (1954) showed that thyroidectomy, treatment with thiourea, or increased doses of thyroxine hinder amphibian regeneration. Nevertheless, Tassava (1969) and Bromley & Thornton (1974) presented data indicating that prolactin when present with thyroxine promotes limb regeneration. Thus these reports suggest some possible relationship of thyroxine to metamorphic changes and capacity for regeneration in the amphibians. However, the role of thyroxine and other thyroid secretions in regeneration of reptiles is still unknown. The following communication describes an attempt to examine histological differences in the thyroid activity in the normal scincid lizard, Mabuya striata. and those showing different stages of tail regeneration, with a view to assessing the role of thyroid secretion in the regenerative processes of this reptileItem Reaction of some arylacetic acids and related compounds with alkaline sodium hypochlorite solution(Royal Society of Chemistry, 1978) Kaberia, Festus; Brian, VickeryItem Pea Aphid: Interaction of Insecticides and Alfalfa Varieties(Entomological Society of America, 1978-02) Mueke, J. M.; Manglitz, G. R.; Kerh, W. R.Carbofuran, methoxychlor, Mobile MCA-600 (benzo [b]thien-4-yl methylcarbamate), leptophos, methidathion, and dialifor were evaluated for control of Acyrthosiphon pisum (Harris) on the alfalfa varieties `Cody', `Dawson',` Team', and `Vernal' in the greenhouse. Dawson and Team are resistant to pea aphids; Cody and Vernal are susceptible. Use of leptophos significantly increased pea aphid numbers on the resistant variety Team but only slight increases resulted from its use on resistant Dawson, with slight decreases in pea aphid numbers following its use on susceptible Vernal. The other insecticides, with the exception of methoxychlor, effectively reduced pea aphid numbers. There were indications that carbofuran, Mobil MCA 600, leptophos, and dialifor increased growth rate of some of the alfalfa varieties, possibly because of aphid control. However, the height of Team was reduced by carbofuran, methoxychlor, and methidathion.In an outdoor cage, leptophos, as the only treatment, also significantly increased pea aphid numbers on Cody, Team, and Vernal but not on Dawson. In a field study with carbofuran, leptophos, and methidathion, the leptophos treatment increased pea aphid numbers (but not to the point of significance) on Dawson and Vernal but not on Team. It was not determined whether the increase in pea aphid numbers was due to change in physiology of the aphid or its host or both.Item Reproductive Biology of Tilapia zillii (Gervais) in Lake Naivasha, Kenya(Kluwer Academic Publishers, 1979) Siddiqui, A. Q.Tilapia zillii breeds all year round in the equatorial Lake Naivasha with slightly high breeding intensity during wet months (March, May and July–August). A sex ratio of 1 : 1.28 was found between males and females. The smallest mature male and female were 9.0 and 11.0 cm respectively. The fecundity ranged from 2990 to 12344 eggs, with a mean of 6606 eggs. Fecundity showed a curvilinear relationship with total length (log F = 1.7034 + 1.6370 log L) and a linear relationship with body weight (F = 2197 + 28.76 W)