Abatement of Polluting Effects of Waste Dump Leachates using Different Coagulants

This study assessed the effectiveness of different coagulants for treating leachates before their release into the environment Three inorganic coagulants ferric chloride ferrous sulphate and alum and one organic coagulant Moringer Oleifera seed MOS were used in a jar test to determine the optimum pH and dosage for the coagulants Raw and treated leachates were analysed for physiochemical parameters such as pH chemical oxygen demand Total solids Pb and Cr The optimum pH for ferric chloride ferrous sulphate alum and MOS was 7 7 6 and 10 respectively While the optimum dosage for each coagulant was 3g L 3g L 5g L and 5g L respectively The analysis of the raw leachate sample showed that it was highly polluted Dry season COD 3000mg L TSS 2369mg L Cr 0 075mg L Pb 0 25mg L and Mn 0 29mg L Wet season COD 3000mg L TSS 2369mg L Cr 0 075mg L Pb 0 25mg L and Mn 0 29mg L Coagulants removal efficiency RE for COD ranges from 12 to 41 with ferric chloride having the highest removal efficiency All the coagulants were efficient in reducing the level of heavy metals in the sample leachate The RE ranges from 55 to 95 6 with MOS having the highest RE of 95 6 for lead The coagulants showed significant difference at P 0 05 in their RE for some of the parameters treated The inorganic coagulants ferric chloride ferrous sulphate and alum showed no significant difference P 0 05 in the removal of COD while the organic coagulant MOS was significantly different at P 0 05 from the inorganic coagulants Over all Alum showed to be a better coagulant than other coagulants in reducing the physiochemical parameters of leachates while MOS is a suitable substitute for alum It was also observed that there was no significance P 0 05 in the removal efficiency of the coagulants in both dry and wet seasons Seasonality has no effect on the effectiveness of the coagulant

Ethnobotanical and in vitro cytotoxicity studies of Moringa oleifera, Andrographis paniculata and Asystasia vogeliana extracts

Ethnobotanical and in vitro cytotoxicity studies were carried out on three different multi- purpose medicinal plants; Moringa oleifera (Lam) (Moringaceae), Andrographis paniculata (Burm. f) and Asystasia vogeliana (Benth) (Acanthaceae). The ethnobotanical information was collected by one to one interview and discussions using semi-structured questionnaires with indigenous people from selected locations in Nigeria. Plant samples collected were identified and authenticated in Forestry Research Institute of Nigeria (FRIN), Ibadan, Oyo State. Each of these three plant samples was extracted in 95% ethanol using a soxhlet extraction apparatus and concentrated to dryness at 45 °C. M. oleifera showed the highest incidence of occurrence (17.5%), fidelity level (74.9%) and multi-purpose usage. The ethnobotanical study revealed the medicinal relevance of the three plants in the treatment of myriads of diseases and ailments including malaria, fever, high blood pressure, cancer, diabetes among others in local herbal medicine. The in vitro cytotoxicity activities of ethanol extracts of the three plant species were screened in two cancer cell lines (BGC-823 and HeLa cells) using the sulphorhodamine B (SRB) assay. Cytotoxicity assay on the two cell lines BGC-823 and HeLa cells revealed that only the ethanolic extract of A. paniculata exhibited some level (moderate) cytotoxicity activity with IC50 values of 24.7 and 23.1 μg/ml respectively. M. oleifera and A. vogeliana did not show any significant activity on the cell lines. The study highlights the importance of ethnobotanical information in finding cost effective, potent and safe herbs for people and screening of the plant species for their activities against cancer cell lines. Further studies on the isolation and characterization of bioactive compounds responsible for cytotoxic effects of A. paniculata is recommended

Nasal Carriage of Staphylococcus aureus and Associated Risk Factors among Students in a Nigerian University

Nasal carriage of Staphylococcus aureus has been associated with subsequent infection and transmission within the hospital and community settings. This study was carried out to evaluate the carriage rates of S. aureus in a University student population and describe risk factors associated with the carriage. Two-hundred and seventy-seven nasal samples were obtained from healthy volunteer students and screened for S. aureus by standard microbiological techniques. Antibiotic susceptibility testing was conducted on the bacterial isolates by the disk diffusion technique. A questionnaire was conducted with each student to acquire demographic and risk factor information. One hundred and fifty-seven (56.7%) isolates were identified as S. aureus. Antibiotic resistance was highest for cloxacillin (91%), ceftazidime (71%), cotrimoxazole (23%), erythromycin (20%) and oxacillin (16%). Risk factors such as hospitalization in the past 12 months, recent skin infection and participation in sports were significantly associated with carrier status. High resistance to certain antibiotics observed in this study shows that nasal colonization could serve as a reservoir of antibiotic resistant strains within the community

Nigerian Science Teachers’ Perceptions of Effective Science Teaching and their Classroom Teaching Practices in Junior Secondary Schools in Lagos State, Nigeria

This study explores science teachers’ perceptions of effective science teaching and their classroom teaching practices. The study was carried out from a population of junior secondary schools in Lagos State, Nigeria. A purposive sample of 78 basic science teachers selected from 61 junior secondary schools from three Education Districts of the state was used for the study. A research instrument tagged effective teaching characteristics questionnaire (ETCQ) was used to elicit information from the teachers. The questionnaire has a test-retest reliability coefficient of 0.83. Data collected were analyzed using frequency counts and simple percentage. The findings indicated that the science curriculum used in schools was overloaded with content to be memorized by learners for examination purposes and that most science teachers engaged students mostly in explanation and demonstration, whole class discussion and note copying. The findings further showed that effective science teaching is characterized by student-centered activities associated with students being attentive, reading notes, doing homework, asking and responding to questions and engaging in regular hands-on practical inquiry-based activity and carrying out their own observations among others. Finally, recommendations for improving science teaching for junior secondary schools in Lagos State were proffered. Keywords: Effective teaching, teacher-centered, perceptions, practical work, teaching resource

Antimicrobial activities and phytochemical properties of Annona muricata leaf

Annona muricata is a well-known economic and traditional plant of Nigeria. The study investigated the properties of constituents and antimicrobial activities of extracts of the leaf of A.muricata. The extracts were tested against Escherichia coli, Pseudomonas aeuroginosa,Staphylococcus aureus and Candida albicans by the agar well diffusion method at concentration of 20 mg/mL. The methanol (AM2) and ethyl acetate (AM4) extracts were characterized using UV and IR spectroscopy.The morphological structure of the A. muricata leaf was observed at a magnification of 20,000X using SEM and then subjected to EDX analysis.The results of the phytochemical screening revealed the presence of phenolic compounds, flavonoids, tannins, alkaloids, saponins and cardiac glycosides in the extracts. Anthraquinone was found absent. The ethyl acetate extract was found highly active against gram positive bacteria, S. aureus (ZI of 42mm; AI = 1.31) and ampicillin resistant gram negative P. aeruginosa (ZI of 34 mm; AI = 1.13). The IR spectra of AM2 and AM4 extracts of A. muricata showed peaks at a frequency of 3377 cm-1 to 3440 cm-1 indicating the presence of a phenolic OH stretch. This supports the phenolics detected chemically. The UV spectrum of methanol extract showed peaks that are typical of flavonoids and phenolics. The SEM revealed the sizes of the leaf particles as inhomogeneous. EDX results showed high oxygen concentration of 73.5 % and carbon concentration of 26.5 %.The findings proved the antiinfective potential of Annona muricata leaf and established physico-chemical markers for the active extracts

Effect of Common Salt on the Engineering Properties of Expansive Soil

This paper investigated the effect of common salt on some geotechnical properties of expansive soil for highway pavement (subgrade) works. In this study, engineering properties including; Natural water content, Atterberg limits, specific gravity, compaction, free swell index, unconfined compressive strength, soaked and unsoaked California bearing ratio were determined in the laboratory and their behavior on stabilizing with various percentages of sodium chloride (0, 0.5, 1.0, 1.5. 2.0 and 2.5) investigated. From the study, plastic limit, liquid limit, plasticity index, linear shrinkage, specific gravity, free swell index and optimum water content values of the stabilized soil reduced, while the maximum dry density, California bearing ratio and unconfined compressive strength values increased. The highest reduction percentages of 60.42 % (131 to 51.85 %), 42.86 % (50.00 to 28.57 %), 71.26 % (81.00 to 23.28 %), 66.64 % (15.11 to 5.04 %), 83.43 % (115.00 to 19.05 %), and 28.57 % (28.00 to 20.00 %) in liquid limit, plastic limit, plasticity index, linear shrinkage, free swell index and optimum water content respectively; and maximum percentage increase of 11.38 % (1.67 to 1.86 g/m3 ,on maximum dry density), 31.78 % (29.20 to 38.48 %, on unsoaked CBR), 257.67 % (4.3 to 15.38 %, on soaked CBR), and 26.98 % ( 67.86 to 86.17 kN/m2 on unconfined compressive strength) were obtained on treatment of the soil with 1.5 % common salt by weight. Treatment of the soil with common salt has thus reduced its swelling potential and increased the strength

Isolation and characterization of β-sitosterol, oleanolic, 19- dehyroursolic and yarumic acids, from Plectranthus esculentus leaves and tubers

Plectranthus esculentus N.E.Br. (family Lamiaceae) also known as Livingstone potato (vat or rizga in Nigeria), is a dicotyledonous perennial shrub growing up to 2 m tall. While it is cultivated mainly for its edible tubers, the plant is potentially valuable as phytomedicine. Three varieties (vat-long’at, vat-riyom and vat-bebot) are well known among the Berom of Plateau State, Nigeria. The vat-bebot variety (which showed good promise in bioactivity studies) was used in this study. The leaves and tubers were extracted successively with hexane, ethyl acetate, methanol and water. Fractionation of the active ethyl acetate extracts was carried out using open column and preparative High Performance Liquid Chromatography (prep HPLC). This led to the isolation of β-sitosterol and oleanolic acid from the leaves; while 19-dehydroursolic acid and yarumic acid, as well as β-sitosterol were isolated from the tubers. Nuclear Magnetic Resonance (NMR) and Electron Impact Mass Spectroscopy (EIMS) were used to characterize isolated compounds. Comparing acquired spectral data of isolated compounds with those from literature helped to confirm the identity of the compounds. The isolation and characterisation of these compounds, from Plecthranthus esculentus, have not been hitherto reported in literature

Synthesis and evaluation of the antimicrobial potentials of cobalt doped- and magnesium ferrite spinel nanoparticles

The high incidence of infectious disease and increase in the incidence of antibiotic resistance has led to the exploitation of inorganic nanoparticles as novel antimicrobial agents owing to their unique physical and chemical properties. This study reports the synthesis and antibacterial activity of magnesium ferrite (MgFe2O4) and cobalt doped magnesium ferrite (Co0.8Mg0.2Fe2O4)spinel nanoparticles (NPs). The NPs were synthesized using the low temperature combustion synthesis. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive absorption spectroscopy (EDAX) were used to characterize the synthesized NPs. The synthesized NPs exhibited good antibacterial properties against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Serratia marcescens. None of the nanoparticles induced any microbial inhibition against Micrococcus varians, Aspergillus flavus, Bacillus substilis and Candida. albicans. Co0.8Mg0.2Fe2O4 NPs gave better antibacterial activity with a zone of inhibition of >20 mm against Staphylococcus aureus and Escherichia coli compared to MgFe2O4 NPs. The minimum inhibitory concentration of Co0.8Mg0.2Fe2O4 NPs against Escherichia coli and Staphylococcus aureus was 2500 µg/mL and 1250 µg/mL, respectively. The relatively high antibacterial effect exhibited by Co0.8Mg0.2Fe2O4 nanoparticles on Escherichia coli and Staphylococcus aureus suggests its potentials in the treatment of infections commonly associated with these microorganisms.               KEY WORDS: Magnesium ferrite, Nanoparticles, Antibacterial activity, Combustion synthesis, Infectious disease Bull. Chem. Soc. Ethiop. 2018, 32(3), 451-458.DOI: https://dx.doi.org/10.4314/bcse.v32i3.