Assessment of Levels of Occupational Exposure to UV-A and UV-C Radiation among Shielded Metal Arc Welders in Accra, Ghana

This study attempted to quantify the irradiance levels of ultraviolet A (UV-A) and ultraviolet C (UV-C) from the shielded metal arc welding (SMAW) process to welders in Accra, Ghana. Exposures were assessed via measurements, observations, and interviews. The assessments were done based on safe exposure levels prescribed by recognized international organizations such as the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the American Conference of Governmental Industrial Hygienists (ACGIH). Results from the measured UV-C irradiance levels EUV-C ranged between 0.16 ± 0.08 W/m2 and 10.46 ± 1.96 W/m2 with its corresponding permissible exposure duration tmax‑UV‑C per day ranging from 5.74 s to 367.35 s. The measured UV-A irradiance levels EUV‑A ranged from 0.88 ± 0.03 W/m2 to 23.72 ± 6.66 W/m2 with its corresponding permissible exposure duration tmax‑UV‑A per day ranging from 421.59 s to     11,363.64 s. The obtained effective irradiance Eeff has a range of 2.08 W/m2 to 28.79 W/m2 with the range of permissible exposure duration tmax per day of 1.04 s to 14.40 s. It was found that the total exposure time of the welders exceeded the permissible exposure durations and that the safety practices among the welders were unsatisfactory

A simple method for the extension of shelf life of cultures of Phytophthora species causing black pod disease of cacao (Theobroma cacao L.)

Black pod disease of cacao caused by Phytophthora palmivora and Phytophthora megakarya in Ghana take heavy toll of cacao production in the field. Intensive research has been carried out worldwide on these pathogens. However, viability of the cultures during prolonged storage has remained a major challenge in the research. This paper reports findings of assessment of six storage media viz sterilised distilled water (SDW), sterilised and unsterilized soil suspension (SSS and USS), vegetable 8 juice broth (V8JB), Oat Meal Agar slant under mineral oil (at 4°C) and empty tube. Viability of the cultures was assessed on V8JA and in tetrazolium chloride test. Ability of zoospores of the cultures to infect cacao leaf discs was used to assess growth vigour and pathogenicity. Phytophthora cultures stored in SDW (26 ± 2°C; alternating day light and night) were preserved for 60 days (5 years). Both P. palmivora and P. megakarya performed better on SDW and SSS than on USS due to removal of staling substances in the soil medium by the sterilisation. Vigour of growth and pathogenicity of the stored cultures required re-inoculation of host tissue (cacao pod) in order to maintain potency to continually infect host

Multi-Modal, Surface-Focused Anticoagulation Using Poly-2-methoxyethylacrylate Polymer Grafts and Surface Nitric Oxide Release

This study examines platelet adhesion on surfaces that combine coatings to limit protein adsorption along with “anti-platelet” nitric oxide (NO) release. Uncoated and poly-2-methoxyethylacrylate (PMEA) coated, gas permeable polypropylene (PP) membranes were placed in a bioreactor to separate plasma and gas flows. Nitrogen with 100/500/1000 ppm of NO was supplied to the gas side as a proof of concept. On the plasma side, platelet rich plasma (PRP, 1 × 108 cell/mL) was recirculated at low (60)/high (300) flows (mL/min). After 8 hours, adsorbed platelets on PP was quantified via a lactate dehydrogenase assay. Compared to plain PP, the PMEA coating alone reduced adsorption by 17.4 ± 9.2% and 29.6 ± 16.6% at low and high flow (p \u3c 0.05), respectively. NO was more effective at low plasma flow. At 100 and 500 ppm of NO, adsorption fell by 37.9 ± 6.1% and 100 ± 4.7%, (p \u3c 0.001), on plain PP. At high flow with 100, 500, and 1000 ppm of NO, adsorption reduced by 17.9 ± 17.8%, 46.4 ± 23.2%, and 100 ± 4.8%, (p \u3c 0.001), respectively. On PMEA-coated PP with only 100 ppm, adsorption fell by 69.7 ± 6.8 and 65.6% ± 16.9%, (p \u3c 0.001), at low and high flows respectively. Therefore, the combination of an anti-adsorptive coating with NO has great potential to reduce platelet adhesion and coagulation at biomaterial surfaces

Iron and manganese accumulation potential in water distribution networks

The occurrence of discoloured drinking water at customers’ taps, which is mainly caused by the deposition and release of iron (Fe) and manganese (Mn) in water distribution networks (WDNs), is a major concern for both customers and water companies. Increased concentrations of Fe and Mn in WDNs can lead to penalisation by the Drinking Water Inspectorate (DWI) and Water Services Regulation Authority in England and Wales (Ofwat). These high concentration levels can cause aesthetic problems such as giving water an unpleasant metallic taste and staining of laundry. It has also been found that increased Mn concentrations in drinking water can reduce intellectual function of children. Despite efforts by water companies to comply with standards for drinking water, they continue to receive customer complaints related to water discolouration. Currently, most water companies identify high-discolouration-risk regions in WDNs by either selecting areas in the network with high concentrations of Fe and Mn from their routine sampling, or using data obtained from customer complaints related to discolouration. However, these risk assessment methods are imprecise, because only few selected nodes are sampled and not all customers who experience water discolouration complain. Moreover, considering that the water mains in England and Wales span approximately 315,000 km, monitoring Fe and Mn concentrations will always be a difficult and expensive task. It is therefore imperative for water companies to gain a practical understanding of the processes and mechanisms that lead to water discolouration, and to develop a model to identify the high-risk areas in WDNs so that remedial measures can be effectively implemented.The factors that influence Fe and Mn accumulation from post-treatment to customers’ taps through WDNs can be categorised into physical, chemical and biological. However, to date, researchers have only studied these factors partially or separately, but never in combination. None of the current models are able to predict discolouration/Fe and Mn accumulation potential for every node in WSZs using chemical, biological, and hydraulic/physical variables. This study took a holistic approach in investigating these factors. A five-year data set comprising of 36 water quality, hydraulic, and pipe-related variables covering 176 different district metered areas (DMAs) were analysed to identify relevant variables that influence Fe and Mn accumulation potential. Customer complaint data were also investigated for seasonal trends. Majority of the DMAs (67.44%) showed significant peaks in customer complaints during summer. These spikes may be attributed to increased water consumption and warmer water temperatures during this period. An artificial neural network (ANN) model was developed using relevant variables identified through the data analysis. The model could predict Fe and Mn accumulation potential values for every node in a given water supply zone (WSZ). From the risk maps generated by the ANN model, it was observed that most of the regions in the network with high Fe and Mn accumulation potential also had high levels of customer complaints related to discolouration. Although the ANN model could predict Fe and Mn accumulation potential failures in WSZs, its black-box nature made it difficult to explain the causes of the failures, unless they were manually investigated.To overcome the limitation in the ANN model, a fuzzy inference system (FIS) was developed to predict Fe and Mn accumulation potential for every node in WDNs and also capture the chemical, biological and physical processes as water travels through the network. The rules and weights of the rules for the FIS were calibrated using a genetic algorithm. The FIS is also able to determine the causes of the Fe and Mn accumulation potential failures. The ability of the developed models in this research to predict and indicate the causes of high Fe and Mn accumulation potential at the node level make them a unique and practical tool to detect high risk nodes in all regions in WDNs, including regions which have not been sampled. Both models could be of great benefit to water resource engineers and drinking water supply companies in managing water discolouration. They could also be used to investigate variables that influence physical, chemical and biological processes in WDNs

The Importance of the Informal Sector of Ghana to Savings and Loans Companies

The informal sector plays a critical and controversial role. It provides jobs and reduces unemployment and underemployment, but in many cases the jobs are low-paid and the job security is poor. It bolsters entrepreneurial activity, but at the detriment of state regulations compliance, particularly regarding tax and labor regulations. In the mist of this controversy, a growing number of savings and loans companies have made the sector their primary target. It was therefore necessary to conduct a research to investigate the importance of the informal sector to savings and loans companies. The objectives of the research were to examine the risks of the informal sector to savings and loans companies, to examine the benefits of the informal sector to savings and loans companies and to assess relationship between the informal sector and savings and loans companies. The research adopted both probability and non-probability sampling methods. A quota of 15 respondents was given to each of the four companies namely Procredit, Ezi, Opportunity and Garden City Savings and Loans companies. Then the purposive and simple random techniques were used to select the 15 respondents of each company. The purposive technique was used to select accountants and marketers of the companies. This was due to the category involvement, knowledge and experience. The simple random technique ensured that each respondent stood an equal chance of being selected. The sample size for the study was 60. The research found out that the informal sector is highly important to savings and loans companies in Ghana as the benefits of doing business with them far out-weighs the associated costs. Key words: Informal sector, Savings and loan

The Importance of Supplier Segmentation to the Manufacturing Sector of Ghana

This study investigated the importance of Supplier Segmentation to the manufacturing sector of Ghana; using selected manufacturing companies the in Eastern and Volta regions of Ghana as case study. Managing relationships between a supplier and buyer can be a complex one. Each party seeks to maximize its time, resources, and cash investment; these may be competing priorities that can strain the relationship. While certain companies adopt a more collaborative approach in dealing with suppliers, others too adopt a take it or leave it approach. In the midst of this controversy, it became necessary to conduct a research to assess the importance of supplier segmentation which has been hailed as a key component of Supplier Relationship Management. The case studies for this study were the management of Volta Star Company Ltd, Akosombo Textiles and the Intravenous infusions Limited. Based on the simple random, purposive, and quota sampling techniques 60 managers from these companies were sampled. The study revealed that Supplier Segmentation is highly important to the Ghanaian manufacturing sector. Key words: Supplier Relationship Management, Supplier Segmentatio

Hemocompatibility Comparison of Biomedical Grade Polymers Using Rabbit Thrombogenicity Model for Preparing Nonthrombogenic Nitric Oxide Releasing Surfaces

Nitric oxide (NO) is an endogenous vasodilator as well as natural inhibitor of platelet adhesion/ activation. Nitric oxide releasing (NOrel) materials can be prepared by doping an NO donor species, such as diazeniumdiolated dibutylhexanediamine (DBHD/N2O2), within a polymer coating. The inherent hemocompatibility properties of the base polymer can also influence the efficiency of such NO release coatings. In this study, four biomedical grade polymers were evaluated in a 4 h rabbit model of thrombogenicity for their effects on extracorporeal circuit thrombus formation and circulating platelet count. At the end of 4 h, Elast-Eon E2As was found to preserve 58% of baseline platelets versus 48, 40, and 47% for PVC/DOS, Tecophilic SP-60D-60, and Tecoflex SG80A, respectively. Elast-Eon also had significantly lower clot area of 5.2 cm2 compared to 6.7, 6.1, and 6.9 cm2 for PVC/DOS, SP-60D-60, and SG80A, respectively. Based on the results obtained for the base polymer comparison study, DBHD/N2O2-doped E2As was evaluated in short-term (4 h) rabbit studies to observe the NO effects on prevention of clotting and preservation of platelet function. Platelet preservation for this optimal NO release formulation was 97% of baseline after 4 h, and clot area was 0.9 cm2 compared to 5.2 cm2 for controls, demonstrating that combining E2As with NO release provides a truly advanced hemocompatible polymer coating for extracorporeal circuits and potentially other blood contacting applications

Grain quality characteristics of imported rice in Ghana: Implications for breeding for consumer-preferred varieties

ABSTRACTRice is the fastest growing food source in Ghana. The country, however, imports about 70 per cent of its rice requirement due to low volumes of production and poor grain quality of domestic rice compared to imported ones.  In the study, 10 popular imported rice brands on the Ghanaian market were characterised for grain quality traits including grain dimensions, apparent amylose content, gelatinisation temperature, paste viscosity properties, and aroma using physiochemical properties and DNA markers. The rice brands came from Asia and the USA. The rice type from Asia was found to be Jasmine-styled aromatic long grained with low amylose content and gelatinisation temperature, whereas those of USA were conventional long grain with intermediate amylose content and gelatinisation temperature.  These findings were confirmed through DNA marker analyses, with the rice types from Asia and the USA revealing the presence of the TAC and GCC of the waxy gene SNP haplotypes, respectively. The implication for rice breeding in Ghana is discussed.Original scientific paper. Received 29 Oct. 14; revised 03 Aug 15