- ItemOpen AccessEffects of reinforcement Particle Sizes on Mechanical Properties of Aluminium/Egg Shell Composites(University of Lagos Press, Akoka, 2016) Agunsoye, J.O; Bello, S.A; Yekinni, A.A; Raheem, I.A; Awe, O.IThe 100 and 150 μm sized CaCO3 particles (sourced from eggshells) from 2-12 wt.% by were used as reinforcements for the fabrication of Al ceramics composites using compo cast technique. The technique involves manual stirring of Al alloy melt-CaCO3 particle mixture prior to pouring process. The morphology of the CaCO3 particles and Al alloy/CaCO3 composites were examined using scanning electron microscope (SEM). The mechanical properties of the fabricated Al alloy / CaCO3 composites were investigated. The result obtained from SEM analysis revealed that the microstructures of Al alloy/100 μm CaCO3 composites are finer than those of their counterparts. This justifies better interaction of 100 μm with Al alloy than 150 μm CaCO3 particles which may be attributable to particle diffusion enhancement due to a decrease in the particle size. Al alloy/100 μm CaCO3 composites displayed higher tensile strain than Al alloy/150 μm CaCO3 composites. Hence the use of 100 μm sized egg shell particles for reinforcement has experimental proven advantages over 150 μm sized CaCO3 particles. Keywords:
- ItemOpen AccessThe Effects of Resin Matrix Composition, Filler Volume and Particle Size on the Mechanical Properties of Dental Resin Composites(University of Lagos Press, Akoka, 2016) Adeleye, O.A; Fakinlede, O.A; Makinde, J.TThe behaviour of dental resin composites (DRC’s) under mechanical loading has been of concern in dentistry as it determines their clinical application. The aim of this study is therefore to check the effect of the resin matrix composition, filler volume and particle size on the mechanical properties of DRC’s. In this experimental in-vitro study, six types of composite resins were used as follows: Two(2) Micro hybrid- Super Cor (SC) and Natural look(NL); Two(2) hybrid- Alpha dent (AD) and Henry Schein (HS) and two(2) Nano hybrid- i-Xcite(IX) and Fusion(FS),each with varying resin matrix composition, filler volume and particle size. Samples were prepared in aluminum molds and light cured using Optilight Max GNATUS light curing unit at constant time intervals of 20 seconds as specified in literature and designed by curing light manufacturers. The specimens were stored in distilled water at 37°C for 48 hours. Subsequently, the specimens were subjected to tensile test and three point loading using the BOSE Electro Force 3200 system at cross head speed of 1.0mm/min and varying speed of 0.5, 2.0 and 5.0mm/min. Henry Schein 20/20 (hybrid;bis-GMA;56%) exhibited flexural strength of 17MPa but tensile strength of 29.7MPa amongst the group. i-Xcite (nanohybrid; bis-GMA,TEGDMA,UDMA;76.5%) showed the flexural strength of 138MPa and relatively low tensile strength of 25.3MPa. All resin types showed increasing flexural strength with increasing strain rate. Tensile and Flexural strength are dependent on the resin matrix composition, the filler particle size and then the filler volume in that order. Keywords:
- ItemOpen AccessLiquid Chromatographic Technique for the Simultaneous Determination of Sulphamethoxazole and Trimethoprim in Pharmaceutical Formulations(University of Lagos Press, Akoka, 2016) Olusegun, A.O; Hamed, N.C; Olajire, M; Oladipo, O.JThis paper describes the development and validation of a simple, specific, precise, and accurate Liquid Chromatographic method for the simultaneous determination of sulphamethoxazole and trimethoprim in pharmaceutical dosage forms. The chromatographic resolution was achieved with 50mM sodium phosphate buffer and acetonitrile (85:15) on a reversed phase column - Octyldecylsilane C18 column (100 x 4.6 mm, i.d., 5μm) - at ambient temperature. The flow rate through the column was 1ml/min and the UV detection was at 260nm using Agilent HPLC 1100LC System. The mean retention times for trimethoprim and sulphamethoxazole were 2.998 and 6.205 minutes respectively. Calibration curves were rectilinear over the ranges 5–80 mg/L (trimethoprim) and 25–400 mg/L (sulphamethoxazole). The RSD was less than 2.61% and percentage recovery was between91.93% - 103.98% with respect to precision and accuracy. The method has been used to analyze brands of cotrimoxazole tablets. The percentage content of sulphamethoxazole and trimethoprim were found to be comparable with BP 2002 requirement. This method, which has a fair run time of 6 minutes, is cost effective for routine analytical work and for quality control and product monitoring. Keywords:
- ItemOpen AccessKnowledge and Perceived Barriers in the Application of Evidence based Medicalradiography in North Eastern Nigeria(University of Lagos Press, Akoka, 2016) Dlama, Z.J; Samuel, S.L; Abubakar, M; Goni, M; Itopa, R; Mohammed, U.SEvidence Based Medical Radiography (EBMR) is the conscientious and explicit use of information based on the combination of clinical expertise and the best available research evidence and resources available. This study is a survey design aimed at evaluating the knowledge and perceived barriers of Radiographers in the application of Evidence Based Medical Radiography. Forty (40) questionnaires were administered among Radiographers practicing in various states in North Eastern Nigeria out of which 32 (80%) were retrieved. The participants were required to fill a 20 item, self-administered and pretested questionnaires comprising of two sections with questions on demographic data, knowledge, and barriers to the application of EBMR among radiographers. The respondents were between 20 and 56 years, majority were between 26-30 years 56.3%, while 6.3% had the least response.87.5% were males while 12.5% were females. The location of respondents were Yobe15.6%, Gombe 21.9%, Bauchi 9.4%, Adamawa 6.3% and Borno 46.9%.Respondents qualifications were 3.12% Diploma, 90.62%Bachelor’s degree while 6.25% had Master’s degree. 87.5% had good knowledge of EBMR and apply it in practice while 46.9% considered lack of ready access to EBMR resources as important barriers to the use of EBMR in clinical practice. The study showed that radiographers practicing in North Eastern Nigeria had good knowledge of evidence based medical radiography.
- ItemOpen AccessEvaluation of Work Posture and Prevalence of Musculoskeletal Disorders among Dentists in Lagos State(University of Lagos Press, Akoka, 2016) Okodugha, O.J; Umesi, D.C; Okafor, U.A; Odebiyi, D.ODentists spend their work hours performing extremely precise procedures in a small space (the patients’ mouth), and dental work is typically characterized by postures with different degrees of distortion, prolonged static postures, repetitive movements, inadequate lighting, and vibrations. This study was designed to evaluate work posture and prevalence of work-related musculoskeletal disorders (WMSDs) among dentists in Lagos State, Nigeria. A total of 47 practicing dentists (males = 25, females = 22) from two Teaching Hospitals within Lagos state, Nigeria participated in this cross-sectional study. Participants were required to complete a standard Nordic musculoskeletal questionnaire; thereafter their work posture was evaluated using Rapid Entire Body Assessment (REBA) tool. Chi-Square statistic was used to determine association among prevalence of WMSDs, REBA scores and anthropometrics. Prevalence of WMSDs was 66.0%, with the low-back having the highest prevalence (51.1%). REBA scores indicated that most respondents (46.8%) were at Medium risk exposure to WMSDs. There was a significant association (p=0.025) between REBA scores and years of working experience; however there was no significant association (p=0.064) between REBA scores and the report of WMSDs. Work-related musculoskeletal disorder, particularly low back pain, was a common problem among dentists. Awkward postures and sustained contractions can be contributory factors to these disorders. Therefore, interventions such as education on proper work posture, use of personal protective equipment (PPE) such as wrist support, back belt and vibration attenuation gloves, and work-station ergonomics may be essential to reduce risk factors.