Browsing by Author "Ntiamoah, A."
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Item Analysis of the life-cycle costs and environmental impacts of cooking fuels used in Ghana(Applied Energy, 2012-10) Afrane, G.; Ntiamoah, A.This study evaluated the life-cycle costs and environmental impacts of fuels used in Ghanaian households for cooking. The analysis covered all the common cooking energy sources, namely, firewood, charcoal, kerosene, liquefied petroleum gas, electricity and even biogas, whose use is not as widespread as the others. In addition to the usual costing methods, the Environmental Product Strategies approach (EPS) of Steen and co-workers, which is based on the concept of 'willingness-to-pay' for the restoration of degraded systems, is used to monetise the emissions from the cookstoves. The results indicate that firewood, one of the popular woodfuels in Ghana and other developing countries, with an annual environmental damage cost of US$ 36,497 per household, is more than one order of magnitude less desirable than charcoal, the nearest fuel on the same scale, at US$ 3120. This method of representing the results of environmental analysis is complementary to the usual gravimetric life-cycle assessment (LCA) representation, and brings home clearly to decision-makers, especially non-LCA practitioners, the significance of environmental analysis results in terms that are familiar to all. © 2012.Item Comparative Life Cycle Assessment of Charcoal, Biogas, and Liquefied Petroleum Gas as Cooking Fuels in Ghana(Journal of Industrial Ecology, 2011-08) Afrane, G.; Ntiamoah, A.Standard life cycle assessment (LCA) methodology has been used to determine and compare the environmental impacts of three different cooking fuels used in Ghana, namely, charcoal, biogas, and liquefied petroleum gas (LPG). A national policy on the use of cooking fuels would have to look at the environmental, social, and cost implications associated with the fuel types. This study looked at the environmental aspect of using these fuels. The results showed that global warming and human toxicity were the most significant overall environmental impacts associated with them, and charcoal and LPG, respectively, made the largest contribution to these impact categories. LPG, however, gave relatively higher impacts in three other categories of lesser significance-that is, eutrophication, freshwater aquatic ecotoxicity, and terrestrial ecotoxicity potentials. Direct comparison of the results showed that biogas had the lowest impact in five out of the seven categories investigated. Charcoal and LPG had only one lowest score each. From the global warming point of view, however, LPG had a slight overall advantage over the others, and it was also the most favorable at the cooking stage, in terms of its effect on humans. © 2011 by Yale University.Item Molecular Docking and Dynamics Simulation Studies Predict Munc18b as a Target of Mycolactone: A Plausible Mechanism for Granule Exocytosis Impairment in Buruli Ulcer Pathogenesis(Toxins, 2019-03) Kwofie, S.K.; Dankwa, B.; Enninful, K.S.; Adobor, C.; Broni, E.; Ntiamoah, A.; Wilson, M.D.Ulcers due to infections with Mycobacterium ulcerans are characterized by complete lack of wound healing processes, painless, an underlying bed of host dead cells and undermined edges due to necrosis. Mycolactone, a macrolide produced by the mycobacterium, is believed to be the toxin responsible. Of interest and relevance is the knowledge that Buruli ulcer (BU) patients remember experiencing trauma previously at the site of the ulcers, suggesting an impairment of wound healing processes, the plausible effect due to the toxin. Wound healing processes involve activation of the blood platelets to release the contents of the dense granules mainly serotonin, calcium ions, and ADP/ATP by exocytosis into the bloodstream. The serotonin release results in attracting more platelets and mast cells to the wound site, with the mast cells also undergoing degranulation, releasing compounds into the bloodstream by exocytosis. Recent work has identified interference in the co-translational translocation of many secreted proteins via the endoplasmic reticulum and cell death involving Wiskott-Aldrich syndrome protein (WASP), Sec61, and angiotensin II receptors (AT2R). We hypothesized that mycolactone by being lipophilic, passively crosses cell membranes and binds to key proteins that are involved in exocytosis by platelets and mast cells, thus inhibiting the initiation of wound healing processes. Based on this, molecular docking studies were performed with mycolactone against key soluble n-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and regulators, namely Vesicle-associated membrane protein (VAMP8), Synaptosomal-associated protein (SNAP23, syntaxin 11, Munc13-4 (its isoform Munc13-1 was used), and Munc18b; and also against known mycolactone targets (Sec61, AT2R, and WASP). Munc18b was shown to be a plausible mycolactone target after the molecular docking studies with binding affinity of −8.5 kcal/mol. Structural studies and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding energy calculations of the mycolactone and Munc18b complex was done with 100 ns molecular dynamics simulations using GROMACS. Mycolactone binds strongly to Munc18b with an average binding energy of −247.571 ± 37.471 kJ/mol, and its presence elicits changes in the structural conformation of the protein. Analysis of the binding interactions also shows that mycolactone interacts with Arg405, which is an important residue of Munc18b, whose mutation could result in impaired granule exocytosis. These findings consolidate the possibility that Munc18b could be a target of mycolactone. The implication of the interaction can be experimentally evaluated to further understand its role in granule exocytosis impairment in Buruli ulcer.