Clinical and audiometric features of presbycusis in Nigerians

Background: Presbycusis is the most common sensory impairment associated with ageing and it presents with variability of symptoms. Physicians need to recognize early clinical and audiometric signs of presbycusis in order to render adequate and quality care to patients and reduce associated morbidities.Objective: To characterize the clinical modes of presentation and the typical audiometric tracings among patients with presbycusis.Methods: This descriptive, prospective hospital-based study was conducted in the Ear, Nose and Throat (ENT) clinic of Olabisi Onabanjo University Teaching Hospital, (OOUTH) Sagamu, Nigeria. Patients with clinical diagnosis of presbycusis confirmed with bilateral sensorineural hearing loss (SNHL) on diagnostic audiometry were administered with questionnaires. Information obtained was analyzed using SPSS statistical package version 17.0 and presented in descriptive forms as percentages, means and graphs.Results: Sixty-nine patients were diagnosed with presbycusis (M:F =1.6:1). Modal age group was 71-80 years. Hearing loss 88.4%, tinnitus 79.7% and vertigo 33.3% were the major symptoms on presentation. The average duration of symptoms before presentation was 2.6 years. There was positive history of ototoxic drugs usage in 24.6 %, family history in 11.6 %, hypertension in 34.8% and osteoarthritis in 13.0%. The most common type of audiometric pattern was strial. Hearing losses increased with age both at the speech and at the higher frequencies of sounds.Conclusions: We found hearing impairment affected both speech and higher frequencies and the strial type of audiometric pattern was most common. The need for screening for hearing impairment from early middle age in symptomatic individuals is emphasized.Keywords: Presbycusis, Nigerians, Audiometry, Clinical features, ElderlyAfrican Health Sciences 2013; 13(4): 886 - 89

Geotechnical Characterization of some Clayey Soils for Use as Landfill Liner

Waste management is one of the major challenges faced by municipality officials, public health engineers and environmentalists in their quest to protect and preserve our environment. Construction and operation of an engineered sanitary landfill ensures proper waste management with the protection of human and ecosystem health. This paper presents the results of geotechnical investigation carried out on clayey soils from three selected pottery areas in Oke Ogun, Oyo State; to assess their suitability for use as landfill liner. Samples were collected at three locations namely: Ajetunmobi village, sample A; Adegbite area, sample B; and Arigangan area, sample C. Basic index characterization tests conducted on the samples revealed percentage fines for samples A,B and C were 32.7%, 28.3% and 37.0% respectively. Specific gravity ranged between and 2 \ub7 71 and 2 \ub7 74. Sample A had Cation Exchange Capacity (CEC) value of 10.58 milli-equivalents/100g (Meq./100g), sample B had CEC value of 11.76 (Meq./100g) and sample C had CEC value of 12.18 (Meq./100g) Geotechnical tests conducted on samples resulted in hydraulic conductivity (k) of 1.86 7 10-10m/sec for sample A ; 4.12 7 10-8m/sec for sample B and, 2.60 7 10-10m/sec for sample C. The results obtained from the study show that sample A is the best material for a landfill liner based on the hydraulic conductivity criterion, however all the other samples are also useful and can be improved by addition of little percentage of bentonite. The compaction and compressibility characteristics needed in the specifications for the construction and operation of an engineered landfill using these clayey soils are presented

The Stabilization of Weathered Dolerite Aggregates with Cement, Lime, and Lime Fly Ash for Pavement Construction

An experimental program was performed on weathered dolerite specimens stabilized by adding varying percentages of cement (4, 8, 12, and 16) % and lime (6 and 12) % and a combination of lime and fly ash (6% lime + 12% Fly ash and 12% lime + 12% Fly ash) % by dry weight of soil. The strength was examined under three different curing methods, namely, membrane curing (MBC), alternate moist-air curing (MAC), and water curing (WAC), by conducting unconfined compressive strength (UCS) tests. Simple polynomial and linear functions (regression models) were used to define the relationships between the variables investigated. Membrane curing (MBC) gave results close enough to the water curing (WAC) to indicate that it can be confidently used on the field during pavement construction. From the results obtained, for class B (interurban collector and major rural roads) pavement construction, addition of 8% cement was recommended for road base construction with stabilized WDA. Also the addition of 12 + 12% Lime and Fly Ash was recommended for road subbase construction with stabilized WDA. Stabilized WDA against the prejudiced myths would perform satisfactorily for base and subbase construction in both heavily trafficked and low volume roads with economic quantities of cement, lime, and fly ash in South Africa

SITE REMEDIATION IN NIGERIA: PROVEN AND INNOVATIVE TECHNOLOGIES (RECOVERY OF FREE HYDROCARBON FROM SOIL/GROUNDWATER)

This research is concerned with geo-environmental impact assessment and remediation of contaminated soil/groundwater. The specific study site is Baruwa community (Latitude 06˚ 35' 12'' N, Longitude 03˚ 16' 21'' E), in Alimosho Local government area of Lagos state, Nigeria. The estimated 65,000 people of Baruwa own about 350 hand dug wells for domestic water supply; more than 200 of these wells are at present, under lock and key because of the oil seepage from leaking underground NNPC (Nigerian National Petroleum Corporation) pipeline. The Geoenvironmental Engineering research group in F.U.T.Akure, started Geoenvironmental site assessment, geotechnical, background and natural attenuation studies for the site in 2006. This has enabled delineation of the contaminated zone. Eight (8) hydrocarbon recovery/monitoring wells (W16, W17, W18, W19, W20, W42, W43, and W44) and two bore holes (W401 and W402) were used for the pilot recovery test. Existing contaminated water supply wells were used as hydrocarbon recovery/monitoring wells to minimize cost. Two boreholes were installed for soil vapour extracting and gas surveys in addition to the eight existing wells within the 100m x 100m designated pilot test area. We have already established that water supply wells are covered by pure phase leaking hydrocarbon products from the underground pipes. Tested well waters had been found to be as much as 95 percent petrol and up to 600 mm thickness of free hydrocarbon product on top of the ground water. Volumetric characterization of the pure phase hydrocarbon using Oil/Water Interface meter/ areal measurements and monitoring together with assessment of various technologies (Natural Attenuation, In Situ Chemical Oxidation and Bioremediation) for remediation was implemented for this site

Contamination potential of tar sand exploitation in the western Niger-Delta of Nigeria: baseline studies

Exploitation of the tar sands in Ondo State in the Niger Delta is likely to result in some environmental contamination and adversely affect the living conditions of the farmers and fishermen in the area. Three wells were established where samples were taken at 1, 2 and 3 m depth. Although no hydrocarbon contamination was detected in the water from the surface and boreholes, saline intrusion was recorded. This study produces a baseline against which future contamination can be monitored so that preventative measures can be taken to mitigate the effects

Cement stabilization treatment of lead and naphthalene contaminated lateritic soils

This article presents an investigation on the influence of Ordinary Portland Cement (OPC) as a binder in the stabilization treatment of lateritic soil contaminated with lead or naphthalene. To evaluate the performance of the binder, the contaminated soils were tested for mechanical strength and environmental performance before and after the stabiliza­tion treatment. Results showed that the strength as inferred from the unconfined compressive strength (UCS) and cohesion values increased with the addition of the binder. Cement stabilization of the lead contaminated samples also prompted a reduction in the release of lead below the admissible limit during the leaching test. Cement stabilization of the naphthalene contaminated samples, on the other hand, could not contain the release of naphthalene below the regulatory level during the leaching test. The batch equilibrium adsorption test (BEAT) showed that cement stabilization increased the adsorption capacity of the soil for the contaminants

SPECTROSCOPIC CHARACTERIZATION OF A NIGERIAN STANDARD SAND: IGBOKODA SAND

-1 reveal the presence of quartz and that it is in the crystalline form. Bands at around 800cm -1 -822.79cm -1 and 786.23cm -1, reveal that the silica is in the form of α-Quartz. The Raman spectrum of the sample has two peaks at around 203cm -1 and 463.07cm -1 for A1 vibrational mode characteristic of quartz. These peaks reflect that the sample studied belongs to the low temperature quartz. The occurrence of the Raman shift at 463.07cm -1 supports the observation from XRD studies which establishes that the quartz observed in this work is α-Quartz. The 29 Si NMR spectrum shows a prominent signal at -107.95 ppm correlating to quartz

Use of Passive Cooling Strategies in Selected Mega-Churches within Lagos-Ogun Megacity, Nigeria

Typically, church buildings are large spaces characterized by infrequent usage at given intervals. Quite often, modern churches rely on air conditioning for the indoor comfort of occupants, which presents challenges for environmental sustainability. However, church buildings, especially in tropical regions, have also adopted passive cooling strategies both as an alternative to air conditioning and as a complement to it, where it helps to reduce air conditioning load and promote environmental sustainability. The aim of this study is to evaluate the use of the passive cooling strategies for achieving environmental sustainability in selected mega-churches in Lagos-Ogun megacity, Nigeria. Qualitative research method was used in this study and primary data was obtained using an observation guide in order to document the passive cooling strategies used in the selected four churches. The results were analyzed using descriptive analysis and presented in texts, plates and tables. From the result, the study found that some of the passive cooling strategies found in literature were employed in the four selected mega-churches although they were not adequate to meet the cooling needs of the large congregation. This resulted in the selected mega-churches relying fully on air-conditioning. The results also showed that passive cooling strategies can be very relevant even in large spaces where they mitigate the air conditioning load. It also indicates that passive strategies can be relied upon when the buildings are used outside the conventional periods, especially for smaller groups of church members. Based on the findings, the study recommends that proper attention should be paid to integrating passive cooling strategies at the initial stage of the design. Additionally, thermal simulations can be carried out to examine the effectiveness of the passive cooling strategies utilized

Dynamics in the murine norovirus capsid revealed by high-resolution cryo-EM

Icosahedral viral capsids must undergo conformational rearrangements to coordinate essential processes during the viral life cycle. Capturing such conformational flexibility has been technically challenging yet could be key for developing rational therapeutic agents to combat infections. Noroviruses are nonenveloped, icosahedral viruses of global importance to human health. They are a common cause of acute gastroenteritis, yet no vaccines or specific antiviral agents are available. Here, we use genetics and cryo-electron microscopy (cryo-EM) to study the high-resolution solution structures of murine norovirus as a model for human viruses. By comparing our 3 structures (at 2.9- to 3.1-Å resolution), we show that whilst there is little change to the shell domain of the capsid, the radiating protruding domains are flexible, adopting distinct states both independently and synchronously. In doing so, the capsids sample a range of conformational space, with implications for maintaining virion stability and infectivity