Volume 5, Issue 1, 2017

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    Open Access
    Estimating Male Ureteral Length with Mathematical Models: Cadaveric Study
    (University of Lagos Press, Akoka, 2017) Oluwatosin, A.T; Osinubi, A.A; Tijani, K.H; Akinde, O.R
    Prior determination of ureteral length before placement of stent helps in pre operation planning for urological surgery. This is an opportunity to select appropriate length of stent. There are evidences of increase in the use of ureteric stents as a result of frequent obstruction of the ureter. This experimental research was carried out on dissected seven male cadavers with measurement of two ureters and eight anthropometric dimensions from each subject. The statistical analysis used includes, mean, correlation coefficient, regression and simulation. There was high correlation coefficient between ureteral length (y) and four out of the considered eight anthropometric measurements: Supra orbital notch to medial malleolus = 0.954; waist circumference = 0.914; Anterior supra iliac spine to lateral malleolus = 0.887; acromion to lateral malleolus = 0.796. Use of mathematical equation and anthropometric measurement of patient will by- pass traditional use of x-ray to evaluate ureteral length when considering the length of the stent to be used by Urologist. Each of the four generated models predicts appropriate length of ureter, thereby reduces cost, within limited time that gives conveniences and comfort to the patient.
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    Open Access
    Forecasting the Tail Density of Nigerian Exchange Rates with a Mixture, Autoregressive Model
    (University of Lagos Press, Akoka, 2017) Akinyemi, M.I; Boshnakov, G.N; Rufai, A
    Density forecasts have become more popular as real life scenarios require not only a forecast estimate but also the uncertainty associated with such a forecast. The class of mixture autoregressive (MAR) models provide a flexible way to model various features of financial time series and are also suitable for density forecasting. This study forecasted the out-of-sample tail density of Nigerian foreign exchange rates using MAR models with Student-t innovations. The model parameters were estimated using the maximum likelihood method. The forecast results of the MAR model were compared with some competing asymmetric Generalised Autoregressive Conditional Heteroskedastic (GARCH) models. Comparisons were based on the Berkowitz tail test. The test results suggested that the MAR model provided the best out-of-sample tail-density forecasts. The findings support the suggestion that the MAR models are well suited to capture the kind of data dynamics present in financial data and provide a useful alternative to other models.
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    Open Access
    Reducing the Observable States Space of Hidden Markov Model for Distributed Denial of Service Attack Prediction using Kullback-liebler Divergence
    (University of Lagos Press, Akoka, 2017) Afolorunso, A.A; Adewole, A.P; Abass, O; Longe, H.O
    Distributed Denial of Service (DDoS) attack floods the network with loads of unwanted packets and requests that weigh down the system resources such as memory and processors. Hidden Markov model (HMM) is one of the models that can be used to predict and detect such attacks. A problem to be solved was determining the observable states and subsequently, the model parameters since the performance of the model depends on the accurate selection of these parameters. In this work, the concept of entropy was used to determine the observable states, which characterise the HMM. In order to improve computational efficiency of the algorithm for estimating the parameters of the model, Kullback-Liebler Divergence (KLD) method was employed for reducing and selecting appropriate observable states to achieve a good prediction model. The experimental results justified the suitability of KLD in reducing the entropy-based observable states of HMM for predicting DDoS attack.
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    Open Access
    Heuristic Approach for Solving Flow Shop Machine Scheduling Problems
    (University of Lagos Press, Akoka, 2017) Adamu, M.O; Idowu, G; Budlender, N
    The problem of scheduling n jobs on m flow shop machines to maximize the (weighted) number of Just-In-Time jobs is considered. It is known that this problem is NP-Complete even for a single machine, indicating that no efficient optimal solution can be found in reliable time for even fairly large instance problems. In this research, two greedy heuristic solutions are proposed and compared with an optimum solution found by Xpress-MP using small problem instances. Computational results and analysis for various scales of instances show that the greedy heuristic algorithms performed creditably well when compared with an optimal solution using small problem instances. The quality and efficiency of the heuristics coupled with solutions to large instance problems are highlighted.
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    Open Access
    Physiochemical Analysis and Isolation of Coliform Bacteria in Water Sample from Female Hostels of a Tertiary Institution in Lagos, Nigeria
    (University of Lagos Press, Akoka, 2017) Egwuatu, T.O; Nsa, I.Y; Ogunlana, F
    Microbial quality and physico-chemical parameters of borehole water from female hostels in an unnamed tertiary institution in Lagos State were evaluated from September to October 2014. A total of seven (7) water samples were obtained and assessed for the presence of coliform bacteria using the most probable number technique (MPN). The study showed the presence of E.coli, Klebsiella spp. and Pseudomonas spp. in some of the water samples assessed. However, contrary to the World Health Organisation’s standards, the physico-chemical analyses showed that some of the water samples had odours and metallic taste. The water conductivity of the samples was within standard limits ranging from 95 μm -288μm. The total hardness of the water was below acceptable limit as it ranged from 10 ppm-25 ppm which was classified as soft water. Some of the water samples were slightly acidic as the pH value of the water ranged from 5.9-7.0, while the acceptable range by WHO is 6.5-8.5. The water samples assessed in these hostels were not fit for drinking based on the microbiological and physicochemical analyses. Therefore, it is highly recommended that the water supplied to these hostels be adequately treated before distribution
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    Open Access
    Growth Pattern, Fecundity, Food and Feeding Habits of Panulirus Regius (De Brito Capello) off the Coast of Nigeria
    (University of Lagos Press, Akoka, 2017) Lawal-Are, A.O; Adefule, A.O
    The spiny lobster (Panulirus regius) off the coast of Nigeria is highly under-studied probably due to lack of stock assessment, accessibility and cost of fishery. In this study, the growth pattern, size composition, fecundity, food and feeding habits of P. regius were carried out off the Lagos Harbour. A total of 120 specimens of P. regius ranging from 13.2 - 28.5 cm in total length were collected. The highest frequency was in the class interval of 15.5 - 16.4 cm. The length - weight relationship showed an allometric growth with weight increasing proportionately with increase in length. The b values were 2.8732, 3.1394 and 2.9635 for male, female and combined sexes respectively. The correlation coefficient (r) for male, female and combined sexes were 0.7373, 0.9231 and 0.8523 respectively, an indication of strong correlation. The stomach contents include fish parts, worm, sea urchin parts, crabs parts and lobster parts while 35 (29.2%) P. regius having empty stomachs. There were 53 males and 67 females giving a sex ratio of 1:1.26 with a chi square (لا²) of 1.64. Out of the 67 females recorded in this study, only17 (25.4%) were fecund. The fecundity estimate in relation to the total length showed a very low negative correlation. P. regius was highly fecund with a range of 109,375 - 494,645 eggs in female of 7.9 – 9.9 cm total length. Barnacle attachments were found on the abdomen and antenna of P. regius studied with preference of attachment to the antenna. There is need for continued research on its management and conservation to improve the paucity of information and stock assessment of the population in order to prevent over-exploitation and under-utilisation to boost its export trade.
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    Open Access
    Modelling and Simulation of Ecap and P-Cap Techniques of Grain Inducement in Mild Steel
    (University of Lagos Press, Akoka, 2017) Esezobor, D.E; Onovo, H.O; Ojo, A.O; Bodude, M.A
    Due to major obstacles associated with the powder consolidation methods of producing bulk nano materials such as high cost, contamination and porosity, severe plastic deformation (SPD) technology, specifically the equal channels angular pressing (ECAP) technique is used with modifications to numerically simulate the much needed grain refinement in steel. Attempts are made in this study to investigate influence of processing parameters such as deformation routes, temperature, load and number of processing passes on the degree of strain inducement in steel. This study however, aimed at developing fourth generation metals of exceptional strength, formability and toughness. The materials used in this work include conventional mild steel and ABAQUS commercial software. Simulation and modeling of the proposed deformation and ECAP techniques were done using finite element based-method (FEM). The results obtained indicate that the desired performance index of the metal is dependent on the state of the metal prior to ECAP and the degree of deformation.
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    Open Access
    Growth and Antidiabetic Activities of Peperomia Pellucida L. Plants Grown under Different Watering Regimes
    (University of Lagos Press, Akoka, 2017) Soboyejo, F; Ade-Ademilua, O.E
    This study was aimed at investigating the potency of Peperomia pellucida plants grown under different watering regimes. Two weeks old seedlings were subjected to daily, 3-days, 5-days and 7-days interval of watering regimes for six weeks. The plant heights, total leaf area, fresh weights and dry weights of plants were measured weekly for six weeks. The rate of growth (all parameters) reduced significantly over time (p < 0.05) as watering regime is prolonged from 3 days to 7 days. Plants were harvested six weeks after watering, dried and blend to powder. The total saponins, total tannins, total alkaloids, total flavonoids and total phenols were analysed. The concentration of phenols and saponins decreased as watering interval increases while the concentration of tannins, alkaloids and flavonoids increased. Alkaloids and tannins were absent in plants watered daily. The study shows presence and concentration of these phytochemicals in plants must be related to soil water availability. Alloxan-induced diabetic rats were fed with extracts from plants subjected to the different watering regimes. The body weight of diabetic rats increased significantly (p < 0.05) with continued treatment with plant extracts (no significant difference between plant extracts) while the blood glucose level decreased significantly (p < 0.05) over time. The blood glucose level of diabetic rats treated with extracts of plants watered at 5-days interval and plants watered at 7-days interval reduced to levels (171 ± 8 mg/ml and 165 ± 11 mg/ml respectively) that were insignificantly different from that diabetic rats treated with standard drug, glibenclamide (152 ± 14mg/ml) by 21 days of treatment. The study suggests that P. pellucida is may be useful as a therapeutic agent in the management of diabetes mellitus and further shows that the potency may be improved by subjecting the plant to water stress.
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    Open Access
    Monitoring of Concentration of Air Pollutants from Vehicular Emission along Major Highways and Bypass within Kosofe Local Government Area, Lagos State
    (University of Lagos Press, Akoka, 2017) Oluseyi, T.O; Akinyemi, M.I
    Vehicular emissions are considered a major source of urban air pollution. Pollutants from these emissions whether as individual compounds or by synergistic interaction impacts negatively on public health, vegetation and climate. In this paper, we evaluate baseline concentration of carbon monoxide (CO), oxides of nitrogen (NOx), sulphur dioxide (SO2) and particulate matter (PM) from vehicular emissions during peak and off-peak periods along 3 major highways within Kosofe and Ikeja Local Government Areas (LGA) of Lagos State. Air quality monitoring/gas detection equipment were used to measure (in-situ method) ambient levels of the pollutant in nine locations within the selected area. The results revealed that the Federal Ministry of Environment’s Ambient Air Quality Standard limit was exceeded by most of the gases in majority of the locations. Statistical analysis revealed significant variations in the concentration of these gases across locations. Heavy vehicular traffic, poor traffic management and frequent traffic congestion were observed as factors responsible for the high pollutant concentration.
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    Open Access
    Table of Content
    (2017) Journal of Medicine, Science & Technology
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    Open Access
    Spectrophotometric and High Performance Liquid Chromatograhic Determination of Sodium Benzoate and Potassium Sorbate in some Soft Drinks
    (University of Lagos Press, Akoka, 2017) Ogunleye, D.T; Oyeyiola, A.O; Onwordi, C.T; Falana, T.G; Abolade, O.M
    Sodium benzoate and potassium sorbate are preservatives commonly used in drinks and their concentration is of importance due to their health implications. This research is aimed at determining the concentration of sodium benzoate and potassium sorbate in some drinks sold in Lagos, Nigeria using high performance liquid chromatography (HPLC) and UV-visible spectrometry. Thirty samples were collected from different super markets in Lagos State and the pH, as well as the concentration of sodium benzoate and potassium sorbate were determined. A significant difference was observed between the HPLC and the UV methods at 95% confidence limit. The concentration of sodium benzoate in the different drinks analysed, ranged from ND to 1040 mg/L and that of potassium sorbate from ND to 499 mg/L. It was observed that about 40 % of the drinks were above the limit of 150 mg/L for benzoate, while 43 % were found to contain concentrations of sorbate above the permissible limits of 250 and/or 300mg/L. The acceptable daily intake (ADI) per kg of body weight of some consumers was exceeded, and this could expose the consumers to the adverse effect of continuous consumption of these drinks. Keywords: Drinks, HPLC, potassium sorbate, sodium benzoate,
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    Open Access
    Mechanical and Wear Behaviour of Heat Treated Aluminium-clay Composite
    (University of Lagos Press, Akoka, 2017) Agbeleye, A.A; Esezobor, D.E; Balogun, S.A; Agunsoye, J.O; Bodude, M.A
    In this paper, the mechanical and wear characteristics of T6 heat treated Al-Clay composite with 15 wt.% at 250μm particle size produced via stir casting method were studied. The samples were solutionised at 500, 550 and 600˚C then quenched in air, oil and water. The samples were artificially aged at 180˚C for 6 hours. Tensile and Vickers hardness tests were conducted on the sample in accordance with ASTM E8/E8M-13 standards. The wear tests were carried out on both pin-on-disc wear-testing machine and in dry sliding conditions at two different loads (4N and 10N) and three sliding speeds (200, 500 and 1000 rpm). Results show that the water quenched composite samples solutionised at 550˚C demonstrated superior mechanical and wear properties. The wear behaviour of the developed composite shows dependence on load, speed and the volume fraction of clay particles. From the results it is concluded that the mechanical and wear properties of Al 6063-clay composite can be enhancedthroughT6 heat treatment process.
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    Open Access
    Removal of Cadmium (II) and Nickel (II) Ions from Aqueous Solution using Corncob Waste
    (University of Lagos Press, Akoka, 2017) Onwordi, C.T; Okwuolise, C.H; Osifeko, O.L; Oguntade, B.K; Wusu, A.D; Petrik, L.F
    The rapid spate of development of many industries has led to wastes containing heavy metals being directly or indirectly discharged into the environment. This study employed the use of corncob an agricultural waste for adsorption of cadmium (II), cobalt (II), and nickel (II) in batch mode at room temperature. The residual metal was determined with flame atomic absorption spectrophotometer. The study investigated the influences of adsorbent dosage, solution pH, contact time, and initial metal concentration on the removal of metal ions. The Langmuir and Freundlich isotherm models were used to fit the equilibrium adsorption data. The reaction kinetics of the cadmium (II), cobalt (II) and nickel (II) removal from the aqueous solution were identified and correlated to the pseudo first and second order kinetic models. The results showed an increase in adsorption by metal ions studied with an increase in adsorbent dosage. Metal uptake showed a pH-dependent profile with optimum at pH values 4.0 for Cd (II) as well as Ni (II), and 8.0 for Co (II) ions. The Freundlich adsorption isotherms model fitted the experimental data best with the regression coefficient ranging between 0.837 and 0.989 for the metal ions. A kinetic study of the adsorption process showed that adsorption of cadmium (II), cobalt (II), and nickel (II) on corncob was observed to follow closely to the pseudo-second–order. It was concluded that corncob exhibited rapid adsorption capabilities and high efficiency in removal of cadmium (II), cobalt (II) and nickel (II) ions from aqueous solution.