An Evaluation of Some Common Laboratory Materials by Xray Attenuation, for use as Human Tissue Substitutes

To develop readily available laboratory materials for probableuse as imaging phantoms or test objects, Laboratory MagnesiumSulphate (MgSO4) and Table salt (NaCl) were used in the ratio80:20% by weight with paraffin wax to form test materials(MgSO4:PW1) and (NaCl:PW2). Rice powder, gelatineseparately, and a combination of gelatine (20g in 100ml of warmwater) and 100g rice powder were also made into test objects.The ratios used were confirmed by matching differentconstituents by weight of the test samples with the web basedphoton interaction software XCOM designed by the NationalInstitute of Science and Technology, USA, to obtain closematching with tissue data. Each test object was made into 1 cmblocks for exposure to narrow beam x-rays over the diagnosticenergy range (50 – 150kV) under automatic exposure conditions.Good agreement within 10%, was found between the measuredand calculated values for four of the five tested samples.Matching of the tested materials with mass attenuationcoefficients of simulated tissue showed acceptable match at highphoton energies of 0.04 – 0,05 MeV and above for gelatine, PW1(paraffin wax + MgSO4.6H2O) and Rigel (Rice + gelatine). Thesematerials can therefore be used as tissue substitutes in imagequality studies

Models for predicting compressive strength and water absorption of laterite-quarry dust cement block using mixture experiment

The use of laterite, quarry dust and recycle aggregates etc as replacement for sand in sandcrete block production is common trend in developing countries like Nigeria. Most resources and research efforts are committed towards conducting trial test with a view to coming up with mix production that will yield the desired property. This work presents a mathematical model for predicting the compressive strength and water absorption of laterite-quarry dust cement block using augmented Scheffe's simplex lattice design. The statistical models developed can predict the mix proportion that will yield the desired property. The models were tested for lack of fit and found to be adequate.Keywords: compressive strength, laterite, mixture experiment, quarry dust, water absorptio

Refractive Error Status In Bayelsa State, Nigeria

Refractive errors affect the whole spectrum of the population without regard to age, gender, race and ethnic group. Uncorrected refractive errors have severe consequences for the individual, family and society.Records showthat no study documenting the distribution of refractive errors in Bayelsa State had been carried out. Records of patients who presented between January, 2004 and October, 2005 in the government-subsidized eye clinic of the Niger-Delta University Teaching Hospital, Okolobiri for refractive error servicewere reviewed.Myopiawas defined as = -0.50DS; hyperopia as = +1.00DS while astigmatismwas definedas = -0.25DC. Emmetropiawas defined as spherical power of -0.25Dto +0.75D. Results of the right eyewere usedfor analysis.Datawere analyzedusingthe Statistical Package for Social Sciences (SPSS) version 10. In this retrospective study, a total of 654 patients fitted the inclusion criteria. There were 319 males and 335 females (48.78%and 51.22% respectively) with an age range of 5 - 86 years. Mean age was 42.18±13.1 (95% CI = 41.17 - 43.19) years. Significant refractive error was observed in 355 cases (54.28%) while 299 (45.72%) were emmetropic. Of the 355 with refractive error, 181 (50.99%) were male and 174 (49.01%) were females. Astigmatism was the commonest refractive error (n=162, 45.63%) followed by myopia (n=113, 51.83%) and hyperopia (n=80, 22.54%). The ranges of refractive power were as follows: astigmatism, -0.25DC to -1.75DC; Myopia, -0.50D to -9.00D and hyperopia, +1.00DS to +11.00DS. More males had hyperopia and myopia while more females had astigmatism. Presbyopia as indicated by the use of near addition was present in 490 (74.92%) of the subjects.The results can be used for planning self sustaining refractive error services in the state. Keywords: Emmetropia,Myopia,Hyperopia,Astigmatism, Presbyopia

Portfolio Optimization of Pension Fund Contribution in Nigeria

In this research work, we investigate the optimality of pension portfolio of 2004 pension reform guidelines in Nigeria using the Net Asset Values (NSA) from the First Alliance and Benefits Ltd as our scarce resources. The resources are distributed as different portfolios of asset classes for comparative analysis. Linear programming technique is used to carry out the analysis of the data using TORA Operations Research software to select the optimal mix of opportunities that would maximize the return while meeting the investment conditions set by each portfolio class and other constraints by Pen Com. We conclude that the Pen Com guided portfolio is not optimum as revealed by the hypothesis test. Keywords: Portfolio Optimization, Contributory Pension Scheme, Defined Benefit Scheme Linear Programming

Refractive Error Status in Bayelsa State, Nigeria

Background: Refractive errors affect the whole spectrum of the population without regard to age, gender, race and ethnic group. Uncorrected refractive errors have severe consequences for the individual, family and society. This study , is the first of its kind, to document the distribution of refractive errors in Bayelsa State. Methods: Records of patients who presented between January 2004 and October 2005 in Okolobiri General Hospital—the government-subsidized eye clinic in Okolobiri, Bayelsa State—for treatment were examined. Myopia was defined as ≥- 0.50DS; hyperopia as ≥+ 1.00DS; while astigmatism was defined as ≥- 0.25DC. Emmetropia was defined as spherical power of –0.25D to +0.75D. Results of the right eye were used for analysis. Data were analyzed using the Statistical Package for Social Sciences (SPSS) version 10. Results: A total of 654 patients were analyzed. There were 319 male and 335 female patients (48.8% and 51.2% respectively)with an age range of 5 – 86 years. Mean age was 42.18 years (SD 13.1, 95% CI = 41.17 – 43.19 years). Significant refractive errors were observed in 355 cases (54.3%), while 299 (45.7%) were emmetropic. Of the 355 with refractive error, 181 (51%) were men and 174 (49%) were woman. Astigmatism was the commonest refractive error (n=162, 45.7%) followed by myopia (n = 113, 31.8%) and hyperopia (n = 80, 22.5%). The range of refractive power was as follows: astigmatism, - 0.25DC to – 1.75DC. Myopia, - 0.50D to - 9.00D; hyperopia, + 1.00DS to + 11.00DS; More male patients have hyperopia and myopia while more female patients have astigmatism. Presbyopia as indicated by the use of near addition, was present in 490 (74.9%) of the subjects. Conclusion: Significant refractive error was present in over half of patients presenting in the period under analysis. The range of refractive errors recorded will assist in planning self-sustaining low-cost refractive error services in the state.Key words: refractive error, presbyopia, astigmatism, Bayelsa State, Nigeria

An Assessment of Image Quality of Radiographs in a Nigerian Teaching Hospital by Film Densitometry

3000 radiographs covering chest, upper limb, lower limb,lumbar spine (AP) and skull (PA) from the University ofCalabar teaching hospital (UCTH) were retrospectivelystudied by densitometry to assess the degree of variationin radiographic contrast over a ten year period (1999 –2008). The results show that variation in meanradiographic contrast from year to year was statisticallyinsignificant (p < 0.05) for the respective projectionsstudied. This result implies a relatively basicstandardisation in image quality arising from consistencyin technique acquired over time. The results would serveas a baseline for developing a more robust qualityassurance programme in the hospital

Determination of Optimal Investment Strategies for A Defined Contribution (Dc) Pension Fund with Multiple Contributors, Proportional Administrative Costs and Taxation

This study centres on determining the optimal investment strategies for defined contribution (DC) pension fund with multiple contributors, administration cost and taxation on the invested fund. We assume that a certain proportion of the member’s contributions as administrative cost which is remitted to the pension fund manager also following the Nigerian Pension Reform Act of 2004 the invested fund is subjected to tax. We obtained an optimized equation using Hamilton Jacobi equation, then solve the equation using Legendre transformation method to obtained explicit solutions of the optimal investment strategy for CARA utility function. We observed that the tax has a direct effect on the investment strategies

Ocular problems among public service retirees in a Southern Nigerian Metropolitan City

Background: Advancing age is a recognized risk factor for blindness and visual impairment worldwide. More than 82% of all blind people are 50 years or older. This therefore places a huge public health and socioeconomic burden on the populace, often leading to social dependence.Aim: To determine the pattern, profile, and risk factors of eye diseases among retired public servants in Port Harcourt City, Nigeria.Materials and Methods: Participants were retired public servants who consented to ocular examinations at their pension pay points in Port Harcourt during the 2012 World Sight Day. Visual acuity, ocular examinations including fundoscopy and intraocular pressure measurements were recorded and subsequently analyzed using Statistical Package for Social Sciences version 20. Results: Five hundred and ninety‑two persons were studied; 455 males and 137 females (F: M = 1:3.3). The Mean age was 68.7 ± 7.6 years (range: 56–97 years). Using World Health Organization/ International Agency for Prevention of Blindness criteria for visual assessment 239 (40.4%) had good vision, 203 (34.3%) had moderate visual impairment, 48 (8.1%) had severe visual impairment, while 102 subjects (17.2%) were blind. Cataract was the leading cause of blindness 56 (54.9%), followed by glaucoma 18 (17.7%), uncorrected refractive error 19 (18.6%), and diabetic retinopathy 9 (8.8%).Conclusion: Visual impairment and blindness are common causes of ocular morbidity among retirees of public service in Port Harcourt. It is therefore advocated that special eye health care intervention by governments and nongovernmental agencies be extended to these groups of people.Keywords: Metropolitan city, ocular problems, retiree

Citric acid Production from Agricultural Wastes using Aspergillus niger Isolated from some Locations within Kaduna Metropolis, Nigeria

This investigation was carried out to assess citric acid production by Aspergillus species isolated in some locations within Kaduna metropolis Nigeria using standard methods. Fungal isolates identified as Aspergillus niger were obtained from samples collected from four (4) different locations.  Isolates were subjected to substrate preference test using local substrates such as wheat straw, rice straw and potato peel powder. Wheat straw supported the highest growth value of 41%. Screening of A. niger isolates for the production of citric acid showed that the isolate from Kawo (Kw) gave the highest yield of citric acid (0.38g/100ml) on basal screening media. Optimization of pH and temperature were carried out and the optimum temperature and pH for citric acid production by isolate Kw was 30OC (0.65g/100ml) and pH 6.0. The wheat straw treated with 5 N HCl produced a high yield of citric acid with a value of 25.60g/kg while the untreated wheat straw produced a yield of 13.3g/kg. Molecular characterization to confirm the identity of the fungal isolates was carried out by the amplification and sequencing of the 5.8S gene of the ribosomal RNA and the two intergenic spacers ITS1 and ITS2 of the strains. By comparison (BLAST) of Aspergillus niger isolate to reference sequence in the gene bank, a sequence similarity of 99% to 100% of other Aspergillus niger strain was obtained. Various methods of strain improvement techniques could be adopted to increase citric acid production by the A. niger isolates obtained from this study