526 research outputs found

    Dietary iron overload. the generation of reactive oxygen species and hepatocarcinogenesis in experimental rats (Part 1)

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    A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand In fulfilment of the requirements for the degree of Doctor of Philosophy Johannesburg, 2003Dietary iron (Fe) overload, originally referred to as Bantu Visceral Siderosis, is an Reloading condition that is still prevalent in rural populations of sub-Saharan Africa. The better known Fe loading disease, hereditary haemochromatosis (HFI) is frequently complicated by hepatocellular carcinoma (HCC) and, in rare instances this occurs in the absence of cirrhosis. The latter, together with recent evidence that dietary Fe overload in the Black African carries an increased risk for HCC, suggests that excessive hepatic iron may itself be carcinogenic. The aim of the study was to determine if Fe alone could induce HCC in experimental rat models and, if so, to investigate possible mechanisms of hepatocarcinogenesis. 360 Wistar albino rats (Rattus norvegicus) were divided into 6 groups. The first group, the control animals, was designated C group. Groups 2-6 were Fe-fed alone or in combination with other chemicals: group 2 Fe alone (Fe group), group 3 (Fe + V) vitamins A & E supplementation [50 mg all trans-retinol (vitamin A) and 500 mg a-tocopherol (vitamin E) per kg diet], group 4 (Fe - V) received a diet totally devoid of vitamins A & E, group 5 (Fe + ASA) received 20 mg aspirin (ASA) per day, group 6 (Fe + Cu) received 300 mg/kg diet of copper sulphate (CuS04) supplementation for 12 months followed by 3% copper hydroxide carbonate [CuC03»Cu(0H)2]IT201

    Instructional Strategies for Effective Teaching and Learning of Creative Arts: The Dilemma of Generalist Teachers in Ghana

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    Creative Art was introduced into Ghana s primary school curriculum in 2007 Comprising Performing Literary and Visual Arts Creative Art was intended to foster creativity development among primary pupils However Creative Art is taught by generalist classroom teachers who lack the specialized training knowledge skill and experience to identify efficient teaching-learning strategies that allow pupils to actively participate in art making experiences This study adopted action research to guide 20 Lower Primary teachers in two schools to design and teach activity-based lessons in drawing colourwork weaving printmaking composition and assemblage to 95 pupils using clay crayons drums cardboard glue among other resources The intervention workshops proved that in-service education and training could build the professional capacity of generalist teachers in Ghana to effectively implement the Creative Arts curriculum for primary schools Ghana Education Service should train primary teachers if the objective of developing creative thinkers through Creative Arts could be achieve

    Assessment of Groundwater Quality and its Suitability for Domestic and Agricultural Purposes in parts of the Central Region, Ghana

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    Groundwater in parts of the Central Region of Ghana was assessed to determine its suitability for domestic use and irrigation activities. Stiff and Piper diagrams show that the predominant water type in the area is Na-Cl, which is characterized by relatively high salinities. This water type occurs in aquifers underlying six coastal districts, namely; Abura-Asebu-Kwamankese (AA), Mfantseman (MF), Gomoa East (GE), Awutu Senya (AwS), Effutu (EF) and Cape Coast (CC). Other water types are Ca-HCO3, Ca-SO4 and Ca-Cl, that occur in districts located further away from the coast. Silicate weathering and ion exchange are identified as the geochemical processes responsible for the various ions in the groundwater. Possible processes that could be responsible for the source of Na+ and Cl- are sea water intrusion and dissolution of minerals. The results also show that the groundwater is mainly supersaturated with respect to both calcite and gypsum, indicating high concentrations of both bicarbonate and sulfate ions in solution. This is associated with considerable enrichment of the groundwater with sulfate, bicarbonate, and calcium ions. On a Wilcox diagram, the groundwater samples, mainly from the districts coded as AA, TLD, AS and AN, which are located away from the coast, plot within the “excellent to good” category, suggesting that water from the area is of acceptable quality for irrigation purposes. Similarly, Sodium Adsorption Ratio (SAR) and conductivity values for the groundwater in the AA, TLD, AS and AN districts indicate low SAR and low to medium salinity respectively. Groundwater in aquifers underlying these districts is therefore suitable for irrigation. Generally, groundwater samples from locations along the coast have high salinity and are not suitable for domestic and irrigation purposes. However, about 72% of the water samples predominantly in districts located away from the sea is suitable for the purposes stated

    Effects of Harvest Time and Storage Form on Insect Population and Damage of Maize

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    The aim of this study was to determine the effects of harvest time and storage form on population levels of insect pests and their damage on stored maize. Maize was cultivated on a total land area of 19 x 23m2 during the major season (April to August 2020) and minor season (September to December 2020). Maize was harvested at three stages; early harvest, mid harvest and late harvest. Harvested maize was stored in three ways; husked, de-husked and shelled. Analysis of variance (ANOVA) was applied to the data through Sisvar version 5.6. Insect pests that were sampled during the study were Sitophilus zeamais, Cathartus quadricollis, Carpophilus dimidiatus and Tribolium castaneum. Carpophilus dimidiatus were sampled from treatments during the major season whereas Tribolium castaneum was sampled during the minor season. Sitophilus zeamais and Cathartus quadricollis were sampled in both seasons.  In the major season, late harvest shelled maize (LHS) recorded 689% more S. zeamais numbers as compared to early harvest husked maize (EHH). Mid-harvest husked maize (MHH) had 307% less number of S. zeamais compared to LHS in the minor season. Late-harvest shelled maize (LHS) had the highest percentage insect damaged kernels (86.94%) in the major season

    Callus induction and plant regeneration via leaf segments of three accessions of African rice (Oryza glaberrimaStued.)

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    A study conducted with the aim of developing a protocol for callus induction and plantlet regeneration in vitro from leaf segments of three accessions of African rice (O. glaberrimaSteud.) indigenous to Ghana. Leaf segments of the accessions namely, Guame, N/4 and SARI 1 were assessed for callus induction and plantlet regeneration ability on different concentrations of plant growth regulators, incorporated into Murashige and Skoog, (1962) (MS) basal medium. Frequency of callus induction which was achieved on MS medium supplemented with (0-10) mg/l 2,4-D differed significantly (p≤0.05) among the accessions, as well as among the levels of 2,4-dichlorophenoxyacetic acid (2,4-D) tested. Highest callus induction frequency was exhibited at a concentration of 6 mg/l 2,4-D for all three accessions.Sub-culturing of callus on regeneration medium, which consisted of MS supplemented with (1:0-5) mg/l NAA:BAP resulted in no plantlet regeneration in all tested accessions. Instead, prolific root formation was observed

    Phenotypic and molecular evaluation of maize (Zea may L.) genotypes under field conditions in the Volta region of Ghana

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    Maize streak disease (MSD) is the most devastating and destructive disease of maize (Zea mays L.) in sub-Saharan Africa (SSA). Field trials were conducted in the 2014 minor and 2015 major cropping seasons to screen 16 and 17 maize genotypes, respectively, for high yield and resistance to maize streak virus (MSV) infections. The plants were scored for disease severity at 4, 6, 8 and 10 weeks after planting (WAP) based on a 1-5 visual scale (1= No infection and 5= Very severe infection). Polymerase chain reaction (PCR) test was done to detect the presence of MSV in the diseased leaf samples in order to confirm field resistance. Both phenotypic and PCR test revealed that all the maize genotypes tested in the study were infected by MSV. There was a significant varietal effect on the incidence and severity of MSD in both the major and minor seasonal trials. Genotypes ‘Abontem’,’Aburohemaa’, ‘Akposoe’, ‘Dapango’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Mamaba’, ‘Obatanpa’, ‘Omankwa’ and PAN 12 showed mild disease symptoms during both major and minor cropping seasons. On the other hand, genotypes ‘Dormabin’, ‘Dzinu-Eve’, ‘Enibi’, Keta 60 and PAN 53 exhibited moderate to severe symptoms during the two cropping seasons. Incidence and severity of MSD were significantly higher in the minor season than in the major season, indicating a significant seasonal effect of MSV on the maize genotypes. The yield and yield components were observed to vary significantly among the different maize genotypes and between the cropping seasons with mean yields significantly higher in the major season than in the minor season. Genotypes ‘Abontem’, ‘Aburohemaa’, ‘Akposoe’, ‘Dorke’, ‘Etubi’, ‘Honampa’, ‘Omankwa’, ‘Obatanpa’ and PAN 12 (All improved varieties), which exhibited partial resistance to MSV infection gave high seed yields during both seasons. The improved maize genotypes that were high yielding and resistant to MSV infection should be evaluated for uniform yield trials on farmers’ fields towards their release as varieties to farmers

    A review on a deep learning perspective in brain cancer classification

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    AWorld Health Organization (WHO) Feb 2018 report has recently shown that mortality rate due to brain or central nervous system (CNS) cancer is the highest in the Asian continent. It is of critical importance that cancer be detected earlier so that many of these lives can be saved. Cancer grading is an important aspect for targeted therapy. As cancer diagnosis is highly invasive, time consuming and expensive, there is an immediate requirement to develop a non-invasive, cost-effective and efficient tools for brain cancer characterization and grade estimation. Brain scans using magnetic resonance imaging (MRI), computed tomography (CT), as well as other imaging modalities, are fast and safer methods for tumor detection. In this paper, we tried to summarize the pathophysiology of brain cancer, imaging modalities of brain cancer and automatic computer assisted methods for brain cancer characterization in a machine and deep learning paradigm. Another objective of this paper is to find the current issues in existing engineering methods and also project a future paradigm. Further, we have highlighted the relationship between brain cancer and other brain disorders like stroke, Alzheimer’s, Parkinson’s, andWilson’s disease, leukoriaosis, and other neurological disorders in the context of machine learning and the deep learning paradigm

    Determination of the Loading Mode Dependence of the Proportionality Parameter for the Tearing Energy of Embedded Flaws in Elastomers Under Multiaxial Deformations

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    In this paper, the relationship between the tearing energy and the far-field cracking energy density (CED) is evaluated for an embedded penny-shaped flaw in a 3D elastomer body under a range of loading modes. A 3D finite element model of the system is used to develop a computational-based fracture mechanics approach which is used to evaluate the tearing energy at the crack in different multiaxial loading states. By analysing the tearing energy’s relationship to the far-field CED, the proportionality parameter in the CED formulation is found to be a function of stretch and biaxiality. Using a definition of biaxiality that gives a unique value for each loading mode, the proportionality parameter becomes a linear function of stretch and biaxiality. Tearing energies predicted through the resulting equation show excellent agreement to those calculated computationally

    A MALDI-TOF MS library for rapid identification of human commensal gut bacteria from the class Clostridia

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    INTRODUCTION: Microbial isolates from culture can be identified using 16S or whole-genome sequencing which generates substantial costs and requires time and expertise. Protein fingerprinting via Matrix-assisted Laser Desorption Ionization-time of flight mass spectrometry (MALDI-TOF MS) is widely used for rapid bacterial identification in routine diagnostics but shows a poor performance and resolution on commensal bacteria due to currently limited database entries. The aim of this study was to develop a MALDI-TOF MS plugin database (CLOSTRI-TOF) allowing for rapid identification of non-pathogenic human commensal gastrointestinal bacteria. METHODS: We constructed a database containing mass spectral profiles (MSP) from 142 bacterial strains representing 47 species and 21 genera within the class Clostridia. Each strain-specific MSP was constructed using >20 raw spectra measured on a microflex Biotyper system (Bruker-Daltonics) from two independent cultures. RESULTS: For validation, we used 58 sequence-confirmed strains and the CLOSTRI-TOF database successfully identified 98 and 93% of the strains, respectively, in two independent laboratories. Next, we applied the database to 326 isolates from stool of healthy Swiss volunteers and identified 264 (82%) of all isolates (compared to 170 (52.1%) with the Bruker-Daltonics library alone), thus classifying 60% of the formerly unknown isolates. DISCUSSION: We describe a new open-source MSP database for fast and accurate identification of the Clostridia class from the human gut microbiota. CLOSTRI-TOF expands the number of species which can be rapidly identified by MALDI-TOF MS
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