Extended Langmuir model fitting to the filter column adsorption data of copper and zinc

This study involved laboratory scale experiments to test the efficiency of washed quarry dust (WQD) in the removal of heavy metals such as zinc and copper from wastewater of electroplating industry, before their safe disposal into public sewer. The washed quarry dust collected from Aristocrust quarries in Mlolongo was prepared and characterized for various physiochemical properties. The wastewater samples were collected from Master Platers Ltd, located in Nairobi’s industrial area. To determine the heavy metals’ removal efficiency of WQD, samples of wastewater were treated by column adsorption experiments. The concentration (Co) of heavy metals in the industrial effluent were analyzed and compared to that treated with the adsorbent. The heavy metals analyzed were zinc, copper, cadmium, chromium, arsenic, lead and iron. It was established that zinc and copper concentrations were high in the industrial effluents while the concentrations of other metals were within the requirements of the Kenya Standard; KS1966‐2:2007. Wastewater samples of known heavy metal concentrations (Co) were passed through the 0.5, 0.75 and 1 M columns at varying flow rates of 6, 9 and 12 ml/min. Leachate samples collected at different depths of WQD column were analyzed for concentrations of zinc and copper ions using atomic absorption spectrometer. The removal efficiency was around 94% and 92% for zinc and copper respectively using column depth of 1 M at a flow rate of 12 ml/min. The adsorption model adopted was described by extended Langmuir adsorption isotherm since the adsorption process involved competitive adsorption in the presence of more than one heavy metal in the wastewater. The model represented the data well when adsorption density curves were plotted for model and laboratory test results. From the column experimental results, washed quarry dust filtration has a high potential to be used in the removal of heavy metals from industrial wastewater. Unlike other adsorbents, WQD is readily available, efficient and cost effective.Key words: adsorbent, copper, heavy metals, treatment, wastewater, washed quarry dust (WQD), zin

A Comparison of Cardanol and its Derivatives as Reactive Diluents in Alkyd Coatings

Volatile Organic Compounds (VOC’s) have aroused concern in many parts of the world especially in large cities due to their negative impact to the environment. In the presence of sunlight, VOC react with NOx gases to produce tropospheric ozone, a powerful oxidant and pollutant to the atmosphere. Although most of the VOC’s originate from petroleum products and internal engine exhausts, and plants, a significant amount is derived from solvent based coatings. Cardanyl methyl ether, cardanol acetate synthesized from cardanol and neat cardanol, which was isolated from cashew nut shell liquid, recovered from cashew nut shell and neat cardanol were studied for their characteristics and evaluated for their suitability as reactive diluents in alkyd coatings. These products were found to be compatible with long alkyd coatings. The reactive diluents helped to lower volatile organic compounds (VOC), drying time and application viscosity of alkyd based coatings.  Coatings formed had excellent adhesion, better drying time, and pencil hardness and are cheaper since CNSL is a renewable raw material. VOC reduction to the extent of about 39 % compared to conventional commercial products was realized. Use of the reactive diluents developed  would not only reduce direct pollution through VOC’s from coatings, but also pollution generated from burning cashew nut shells, which is currently widely  practiced  among cashew nut processors. Keywords: Cardanyl methyl ether, Cardanol acetate, cardanol, reactive diluent, Alkyd Coating

The incidence and risk factors for intra-operative hypothermia among paediatric patients undergoing general anaesthesia at the Kenyatta National Hospital

Objective: To determine the incidence and risk factors for intra-operative hypothermia in paediatric patients undergoing general anaesthesia at the Kenyatta National Hospital. Design: A prospective observational study.Setting: The Kenyatta National Hospital main operating theatres and affiliated satellite operating theatres.Subjects: A total of 100 paediatric patients (range; three days to 12 years, mean; 4.1 ± 3.3 years) were enrolled in the study.Results: Thirty out of 100 patients developed hypothermia defined as a core temperature <36ºC recorded at least once during provision of general anaesthesia. Ninety percent of those developing hypothermia were male compared to 63% who remained normothermic (p = 0.006). Proportionally, more than twice as many hypothermic patients had a caudal block (43% versus 20%, p = 0.016) and received 121ml more of fluid (p = 0.002) compared to the normothermic group. The patients who became hypothermic tended to be colder at induction of anaesthesia (36.6 ± 0.5ºC versus 37.0 ± 0.5ºC, p = <0.0001) but there was no significant difference in the waiting time, time of  induction, environmental temperatures or theatre temperatures compared to those not developing hypothermia. There was no significant difference in the BMI between the two groups (14.0 ± 2.9 kg/ m2 versus 15.2 ± 3.5 kg/m2, p = 0.101).Conclusion: The incidence of intra-operative core hypothermia in paediatric patients undergoing general anaesthesia at the Kenyatta National Hospital is 30%. Gender (male), lower body temperature at induction, use of caudal block and the volume of intravenous fluids infused were significant independent predictors of core hypothermia. The most significant predictor was body temperature at the time of induction of general anaesthesia

Phytochemicals Present in Engleromyces goetzei and Antimicrobial Activity Against Phytopathogenic Bacteria

Interest in the extraction of bioactive compounds from natural sources has increased in recent years due to the potential applications of these compounds in food, chemical, and pharmaceutical industries. The methanolic extract of the fungus Engleromyces goetzei was investigated for the presence of phytochemicals and the antibacterial properties. The study shows that the extract has flavonoids, coumarins, saponins, terpenoids and steroids. Engleromyces goetzei has potential as a source of useful antibacterial compounds active against phytopathogenic bacteria. Disk diffusion assay was used to analyze the susceptibility of an organism which help in identifying the proper antibacterial biopesticide. In this experiment, this was done by placing the antimicrobial disks impregnated with E. goetzei on the NA plates swabbed with Xanthomonas campestris, Pseudomonas sryingae pv phaseolicola, Erwinia carotovora and Xanthomonas axonopodis pv. phaseoli. After twenty-four hours of incubation, there were areas around the antimicrobial disks with no bacterial growth. The MIC of E. goetzei against X. axonopodis pv. phaseoli, Ps. syringae pv phaseolicola and X. campestris was found to be 1mg/ml while that of E. carotovora was 10mg/ml. Keywords: Phytochemicals, Engleromyces goetzei, X. axonopodis pv. phaseoli, E. carotovora, Ps. syringae pv phaseolicola, X. campestri

Effect of Inoculation with Mycorrhizae on Growth Parameters of Dombeya torrida, Leucaena leucocephala and Tephrosia vogelii

The present work evaluated the impact of arbuscular mycorrhizal (AM) fungus on growth. Three species of trees, Tephrosia vogelii, Leucaena leucocephala and Dombeya torrida were treated with fragments of arbuscular mycorrhizae and grown in greenhouse. The aim of the present work was to determine whether arbuscular mycorrhizal symbiotic association with these tree species would enhance their growth. Data on height, stem diameter and number of leaves were taken after every two weeks for a period of three months. Mycorrhizal plants demonstrated higher vigor with Tephrosia vogelii giving a mean height of 57.50 cm, 0.50 cm diameter and 9.33 number of leaves which were significantly different from the control plants at p ≤ 0.05 according to least significant difference (LSD). The biomass was also taken at the end of 90 days of growth and the same trend was exhibited. Mycorrhizal plants also showed root nodules with mycorrhizal arbuscles. This work contributes to our understanding of the effects of AM symbiosis on the accumulation of certain micronutrients in valuable woody tree species. Keywords: arbuscular mycorrhizae, Tephrosia vogelii, Leucaena leucocephala, plant growt

Biocontrol of Green Mould Disease of Oyster Mushroom (Pleurotus ostreatus) using Bacillus amyloliquefaciens

The occurrence of Trichoderma harzianum and T. asperellum in cultivation of oyster mushroom (Pleurotus ostreatus) frequently results in serious crop losses and considerable inhibition of growth of mycelium and fruiting bodies of oyster mushroom thus lowering the yield substantially. Bacillus amyloliquefaciens strain isolated from groundnuts proved very effective in antagonizing the oyster mushroom pathogenic T. harzianum and T. asperellum without having a negative effect on P. ostreatus mycelia. The Bacillus amyloliquefaciens was found to produce diffusible and volatile organic compounds. This strain is a potential biocontrol candidate, in addition to the lack of antagonistic activity towards P. ostreatus mycelia. The present study, hence, provides a potential biocontrol agent for Trichoderma green mould. However, field studies of this isolate as substrate inoculant in oyster mushroom are required in order to establish its actual performance. Keywords: Bacillus amyloliquefaciens, Green mould, Mushroom, Biocontro

Fodder legumes technology and farmer to farmer extension: a case of Desmodium and Calliandra in central Kenya

Adoption studies on fodders legume technologies have shown that spread of the technology is significantly enhanced by informal methods of dissemination especially farmer-to-farmer extension. It is not known which type of farmers are involved in this dissemination. The objective of this study was to identify farm and farmer characteristics that influence farmer-to farmer extension hence identify the type of farmers that can disseminate fodder legume technologies. A random sample of 130 farmers who had been given calliandra in central Kenya responded to a structured questionnaire. Information collected included farm and farmer characteristics and the number of farmers the original farmer had given Calliandra outside the original group. A tobit model was used to analyze the data to get the magnitude of the effects of factors affecting the probability and the intensity of giving out the fodder. Results showed that farmers with positions in farmer groups** , community responsibility**, larger amounts of desmodium on the their farms** , more years of the fodder on their farms***; low access to markets* and off farm income* , were positively involved in spread of the fodder legume. It was recommended that this type of farmers be targeted with support to increase spread of the technology

Symptom screen: diagnostic usefulness in detecting pulmonary tuberculosis in HIV-infected pregnant women in Kenya

OBJECTIVE: To determine the diagnostic usefulness of tuberculosis (TB) symptom screening to detect active pulmonary TB among human immunodeficiency virus (HIV) infected pregnant women in two PMTCT (prevention of mother-to-child transmission) clinics in western Kenya that are supported by the United States Agency for International Development–Academic Model Providing Access to Healthcare partnership. DESIGN: Cross-sectional study. Participants were interviewed for TB symptoms with a standardized questionnaire (cough >2 weeks, fever, night sweats, weight loss or failure to gain weight). Those with cough submitted sputum specimens for smear microscopy for acid-fast bacilli and mycobacterial culture. Women at >14 weeks gestation underwent shielded chest radiography (CXR). RESULTS: Of 187 HIV-infected women, 38 (20%) were symptom screen-positive. Of these, 21 had a cough for >2 weeks, but all had negative sputum smears and mycobacterial cultures. CXRs were performed in 26 symptomatic women: three were suggestive of TB (1 miliary, 1 infiltrates and 1 cavitary). Of 149 women with a negative symptom screen, 100 had a CXR and seven had a CXR suggestive of TB (1 cavitary, 2 miliary and 4 infiltrates). CONCLUSION: This study did not support the utility of isolated symptom screening in identification of TB disease in our PMTCT setting. CXR was useful in identification of TB suspects in both symptomatic and asymptomatic women

Antimicrobial activities of a novel biflavonoid and other constituents from Rhus natalensis

Phytochemical studies on Rhus natalensis root bark collected from Kenya led to the isolation and identification of a new biflavonoid (3-(1-(2,4-dihydroxyphenyl)-3,3-bis(4-hydroxyphenyl)-1-oxopropan-2- yl)-7-methoxy-4H-chromone-4-one (1), named rhuschromone, in addition to two other known compounds; 2',4'-dihydroxychalcone-(4-O-5''')-4'',2''',4'''-trihydroxychalcone (2) and 3-((Z)-heptadec-13- enyl) benzene-1,2-diol (3). The chemical structures of the isolated compounds were established using spectroscopic techniques including high field nuclear magnetic resonance (NMR). The total extracts and the isolated compounds were tested for their antimicrobial activities against different strains of bacteria

Factors influencing farmer-to-farmer extension of forage legume technology

Forage legumes have been introduced to farmers in Central Kenya between 1980 and 2002 through various Institutional and Projects’ efforts. The adoption rate of these forages among farmers has been found to be rather low, with the NDDP reporting only 1.9 % of farms surveyed and an ICRAF report indicating that the technology was only reaching 1 % of smallholder farms. An evaluation of adoption of Calliandra and Desmodium was conducted to identify farm characteristics affecting the likelihood of sharing of Desmodium and Calliandra technologies as well as to characterise the spread or diffusion of the technology from the original contact groups and the effect of distance from those groups. Three groups of farmers were approached. A first generation who received planting material from the distributors, a second generation who received planting materials from the former, and a randomly selected group of farmers at various distances from the first contacts. Informal discussions were held with the farmers and formal questionnaires filled. Out of the 133 first generation farmers contacted 64.7% still had Desmodium and 89.5% still had Calliandra. More farms in the contact sub-locations had the plants than the sub-locations further away. The small sample size of those with the forages could not allow effect of distance to be worked out. Tobit estimates of effects of farmer attributes influencing sharing of planting materials shows that the status of the household head in the community positively affected the likelihood of giving out planting material. The technology has a rather slow spread as indicated by percentages of farms with the forages. For better adoption and spread proponents of the technology should have the technology introduced to farmers who have substantial positions in farmer groups or have been bestowed community responsibility