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A long essay or dissertation or thesis involving personal research, written by postgraduates of University of Ghana for a university degree.
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Item Parasitic Nematodes Associated With Yam (Discorea Rotundata) and Morphometric Characterization of Scutellonema Bradys in the Krachi Nchumuru District, Ghana(University of Ghana, 2017-07) Enchill, A.K.A dry rot of yam Dioscorea rotundata which attacks tubers in the field and in storage is currently threatening production of the crop in the Krachi Nchumuru District of the Volta Region No detailed investigation has been conducted therefore a study was carried out from October 2016 to May 2017 to assess the knowledge, perception and experiences of farmers in the District on the occurrence and management of the tuber dry rot disease, isolate, identify and assess plant parasitic nematode genera Krachi Nchumuru District in yam fields and stored yam tubers; determine variation within and among population of Scutellonema. bradys using morphological and morphometric characteristics. Questionnaire were developed and administered randomly to 50 farmers in 10 communities. The questionnaires covered demographic characteristics, land use intensity, farmers’ knowledge, perception and experience concerning occurrence of nematodes in yam fields and stored yam tubers, management and economic importance of yam nematodes. Yam rhizosphere soil samples were collected from 20 farms in the district for nematode extraction using Jenkins centrifugation method. Three stored yam tubers were also collected from the same farmers for nematode extraction using Baemanns extraction method. Morphometric measurements were carried out on populations of the yam nematode S. bradys using compound microscope attached to a computer. The survey revealed that farmers were aware of the tuber dry rot disease, but were however, ignorant about the causes and the spread of the disease, so planting materials were not treated before use. Twelve genera belonging to seven nematode families of order Rhabdida and Dorylaimida were identified in yam rhizosphere soils and nine genera in stored yam tubers. These were Scutellonema spp., Meloidogyne spp. Longidorus spp., Tylenchulus spp., Helicotylenchus spp., Ditylenchus spp., Heterodera spp., Pratylenchus spp., Rotylenchus spp., Appenlenchoides spp., Paratylenchus spp., and Bursaphelenchoides spp., The predominant nematodes Scutellonema University of spp., Meloidogyne spp. and Pratylenchus were present in both soil and yam tuber peels. There were low populations of other nematode genera. The most frequently detected genus was Scutellonema bradys (131) per 200cc of soil and (34086) in 10 gram tubers peels. Agglomerative hierarchical clustering (AHC) revealed 5 groups at a dismilarity of 90%, however sub groups formed at dissimilarity value of 5% Significant morphology variation is present in female S. bradys population.Item Isolation And Characterization Of Cassava Fibre For Tissue Engineering Scaffold Application(University of Ghana, 2017-07) Diabor, E.Cassava bagasse and its extracted cellulose fibres have seen frequent application mostly in the packaging industry as reinforcement material in plastic composites development. However, the material properties such as the mechanical properties of the single elementary cassava cellulose fibres have not been examined and reviewed literature does not show its potential use in the development of tissue engineering scaffolds for cell culture. The study, therefore, characterized the mechanical properties, physicochemical, morphological and microstructural characteristics and thermal degradation profiles of single elementary cellulose fibre as well as the central vascular fibre (“thick-core fibre) isolated from three genotypes of cassava (tagged in this study as ID4, ID6 and AF). Additionally, the study examined the effect of incorporating cassava cellulose microfibres as reinforcement on the mechanical properties and microstructure characteristics of three-dimensional gelatin scaffolds. Non-treated isolated cassava fibres were tested according to ASTM C1557. Three-dimensional cassava microfibre/gelatin scaffolds with different fibre weight fractions were fabricated using phase separation and freeze-drying methods. Tensile test results showed that there was no significant difference (p > 0.05) in mechanical properties recorded between the single elementary fibre and vascular fibre (thick-core) for the three cassava genotypes. Different genotypes of cassava fibre showed significant differences (p < 0.05) in tensile strength and Young’s modulus, with ID4 fibre recording the highest average tensile strength of 7.567 ± 3.844 MPa and highest elastic modulus of 336.485 ±130.803 MPa. XRD analysis showed similar diffraction pattern with minimal variation in signal intensities for both single and thick-core fibres for all cassava genotypes suggesting nonsignificant differences in crystalline structure between them. TGA analysis showed that cassava fibre is thermally stable between the temperatures of 100 °C – 200 °C. The cassava cellulose microfibre/gelatin scaffolds fabricated showed rough surfaces compared to pure gelatin scaffolds and were highly porous with surface porosity ranging between 84 and 90%, and had interconnected pores of average size 36 ±12 μm. Gelatin scaffolds containing up to 7% cassava cellulose microfibre load recorded a maximum compressive strength of 0.29±0.02 MPa, about eight (8) times higher than that for the pure gelatin scaffolds and average Young’s modulus of 1.31 ±0.03 MPa, about four times higher than pure gelatin scaffolds. Preliminary theoretical modelling using Halpin-Tsai model could accurately explain the variabilities in the compression modulus of the gelatin composite scaffolds. In all, the results showed that cassava fibre has considerable mechanical strength and stiffness and can be used as reinforcement filler to improve the mechanical integrity of tissue engineering polymer scaffolds. The cassava fibre/gelatin scaffolds showed surface architecture that could improve cell–matrix adhesion and efficient cell seeding and diffusion of nutrients during cell culture.Item Characterization Of The Geophagic Materials And Their Overlying Rocks And Soils From Anfoega, Ghana(University of Ghana, 2016-07) Badu, J.K.Geophagy is the deliberate consumption of earth and clay deposits by animals, including man. It is a special type of pica, which is defined as the craving and subsequent consumption of non-food substances. This study was conducted to examine the physical, chemical and mineralogical properties of the geophagic materials and their overlying rocks and soils from four sites at Anfoega in order to determine possible relationships among them and the potential human health risk associated with the consumption of the geophagic materials. The four sites were Tokorme 1, Tokorme 2, Tokorme 3 and Wuve. Soil samples and geophagic materials from the selected sites were subjected to the following laboratory analyses: colour, particle size distribution, pH, electrical conductivity, cation exchange capacity, organic carbon content and X-ray defractometry. The rock samples and geophagic materials were also subjected to petrographic and x-ray analysis. Whereas the pH of the soils from Tokorme 1, Tokorme 3 and Wuve ranged from slightly acidic to moderately acidic, that of Tokorme 2 was moderately acidic in the surface soils but strongly acidic in the lower layers. The pH of the geophagic materials was strongly acidic. While the soil samples generally contained high amounts of sand, the geophagic materials contained high amounts of clay. With higher amounts of clay, the CEC of the geophagic materials ranged from 18.0 to 23.2 cmolc kg-1 which was higher than that of the soil samples (5.3 to 22.6 cmolc kg-1). The thin sections of the rocks showed very high amounts of quartz and small amounts of feldspars and sericite. The thin sections of the geophagic materials on the other hand, revealed the presence of large amounts clay and some quartz, feldspars and sericite. The x-ray diffractograms showed that the soils, rocks, and geophagic materials were dominated by SIALIC minerals mainly quartz, kaolinite, muscovite and http://ugspace.ug.edu.gh/ iii feldspar. The mineralogy of the soils indicated that they were derived in-situ from the underlying sandstones. The results also showed that the high amounts of SIALIC minerals in the geophagic materials was accumulated through leaching of the overlying sandstone. The health risk index analysis of the geophagic materials calculated based on consumption of 70 g of clay per day were all less than 1.0. This result indicates that the geophagic materials were safe for human consumption. Also, the microbial analysis of the geophagic materials showed high levels of bacteria load in the processed fresh, processed dry, powdered and smoked samples. However, no coliform group was detected. The microbial results showed that although the geophagic materials were naturally safe for consumption, processing them could introduce harmful micro-organisms.Item Geochemical Characterization And Petrogenesis Of The Scapolite–Bearing Gneisses In The Dahomeyide Suture Zone, South–Eastern Ghana(University of Ghana, 2016-07) Antwi, EAccording to Knorring and Kennedy (1958), scapolite occurs in rock volume proportions of 20% at the Mampong Inselberg but other areas in the Dahomeyide suture zone have scapolite in the mafic gneiss in volume proportions of about 2%.Also, the amphibolite which occurs with the mafic gneiss in the study area is said to have undergone granulite facies metamorphism to produce the mafic gneiss (Fitches, 1970). The petrographical analyses of this research showed that the mafic gneiss has scapolite with 4 to 8 volume percent proportions (vol %).The scapolite observed at the Mampong Inselberg is same as the SO3 variety which is Ca-rich and CO2-bearing (Meionite) found by Knorring and Kennedy (1958), based on the fact that, the bulk geochemical data obtained for scapolite-bearing gneiss in both researches are similar. The Mampong Inselberg and surrounding areas have more amphibolite outcrops and fewer eclogite outcrops as compared to the areas north of the suture zone. This suggests that the areas at the southern part of the suture zone represents the region where the amphibolite facies metamorphism was intensive and this favours the development of the scapolite mineral in greater proportions. The (alkali, iron and magnesium) AFM diagram plotted for the rocks show that the amphibolite plot in the tholeiitic field while the mafic gneiss plot in the calc-alkaline field suggestng that they have two different evolution paths. This is supported by the fact that, on the field, some of the contacts observed between the mafic gneiss and the amphibolite is very sharp and amphibolite boudins also show relative movements with respect to the mafic gneiss. From the chondrite normalized rare earth element (REE) diagrams, the mafic gneiss and amphibolite show patterns which differ slightly from each other and can be likened to that of Lower crust (LC) materials. The amphibolite show a slight negative Europium (Eu) anomaly while the mafic gneiss does not. Spider diagrams also show patterns for the mafic gneiss and amphibolite which can be likened to that of the Lower crust (LC) materials. The patterns displayed by the rocks on the rare earth element diagrams and spider diagrams suggest that the rocks have originated from the Lower crust while other tectonic settings discrimination plots show that the rocks have Island arc tholeiite affinities and hence may have been formed in an Island arc setting.