The tropical environment and malaria in southwestern Nigeria, 1861 – 1960
- Authors: Adetiba, Adedamola Seun
- Date: 2019
- Subjects: Diseases and history -- Africa , Diseases and history -- Nigeria , Medical anthropology -- Africa , Medical anthropology -- Nigeria , Malaria -- Social aspects -- Nigeria , Malaria -- Nigeria -- History , Nigeria -- History , Imperialism -- Health aspects , Medicine -- Colonies -- Great Britain -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76564 , vital:30605
- Description: This thesis is a social history of malaria in southwestern Nigeria. It contributes to the burgeoning literature in the historiography of medicine, specifically the medicine and empire debate. Key to the issues raised in this thesis is the extent to which the limitations in colonial medical policies, most especially malaria control programmes, inspired critical and ingenious responses from African nationalists, doctors, patients, research volunteers, and indigenous medical practitioners. Challenged by a wide range of diseases and a paucity of health facilities and disease control schemes, African rural dwellers became medical pluralists in the ways they imagined and appropriated ideas of Western medicine alongside their indigenous medical practices. Beginning with a detailed historical exploration of the issues that informed the introduction of curative and preventive medicine in southwestern Nigeria, this thesis reveals the focus of colonial medicine. It exposes the one-sided nature of medical services in colonial spaces like southwestern Nigeria and the ways it shaped multifaceted responses from Africans, who were specifically side-lined till the 1950s when the rural medical service scheme was introduced. The focus of colonial medicine is drawn from relatively rich but often subjective historical evidence, such as a plethora of official reports of the department of medical and sanitary services, official correspondences within the colonial government in Lagos and Nigeria, and between the colonial government and the colonial office in the United Kingdom. Details of African responses to medical policies were garnered from newspaper publications and correspondences between the African public and the colonial government in Lagos. They reveal very interesting details of the ways Africans imagined, reimagined, and appropriated malaria control ideas and schemes. The central argument in this thesis is that attempts to control malaria in southwestern Nigeria till the 1950s, were shaped by a single concern to ameliorate the implications of the disease on the colonial state. It argues that this one-sided nature of malaria control programme informed the basis for medical pluralism in most rural spaces where African communities became patrons and sponsors of Western medicine and at the same time custodians of their indigenous medical practices. The series of justifications for the sustenance of these services were reinforced on the basis of the failure of the colonial state to guarantee the health needs of their colonial subjects. The aim of the thesis is to reinforce arguments that portray colonial medicine as a “tool of empire” but goes a bit further to explain the extent to which Africans related to this reality. It states quite categorically that Africans were not docile and silent, but that they acted decisively in ways that suited their varied interests and courses.
- Full Text:
- Date Issued: 2019
- Authors: Adetiba, Adedamola Seun
- Date: 2019
- Subjects: Diseases and history -- Africa , Diseases and history -- Nigeria , Medical anthropology -- Africa , Medical anthropology -- Nigeria , Malaria -- Social aspects -- Nigeria , Malaria -- Nigeria -- History , Nigeria -- History , Imperialism -- Health aspects , Medicine -- Colonies -- Great Britain -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76564 , vital:30605
- Description: This thesis is a social history of malaria in southwestern Nigeria. It contributes to the burgeoning literature in the historiography of medicine, specifically the medicine and empire debate. Key to the issues raised in this thesis is the extent to which the limitations in colonial medical policies, most especially malaria control programmes, inspired critical and ingenious responses from African nationalists, doctors, patients, research volunteers, and indigenous medical practitioners. Challenged by a wide range of diseases and a paucity of health facilities and disease control schemes, African rural dwellers became medical pluralists in the ways they imagined and appropriated ideas of Western medicine alongside their indigenous medical practices. Beginning with a detailed historical exploration of the issues that informed the introduction of curative and preventive medicine in southwestern Nigeria, this thesis reveals the focus of colonial medicine. It exposes the one-sided nature of medical services in colonial spaces like southwestern Nigeria and the ways it shaped multifaceted responses from Africans, who were specifically side-lined till the 1950s when the rural medical service scheme was introduced. The focus of colonial medicine is drawn from relatively rich but often subjective historical evidence, such as a plethora of official reports of the department of medical and sanitary services, official correspondences within the colonial government in Lagos and Nigeria, and between the colonial government and the colonial office in the United Kingdom. Details of African responses to medical policies were garnered from newspaper publications and correspondences between the African public and the colonial government in Lagos. They reveal very interesting details of the ways Africans imagined, reimagined, and appropriated malaria control ideas and schemes. The central argument in this thesis is that attempts to control malaria in southwestern Nigeria till the 1950s, were shaped by a single concern to ameliorate the implications of the disease on the colonial state. It argues that this one-sided nature of malaria control programme informed the basis for medical pluralism in most rural spaces where African communities became patrons and sponsors of Western medicine and at the same time custodians of their indigenous medical practices. The series of justifications for the sustenance of these services were reinforced on the basis of the failure of the colonial state to guarantee the health needs of their colonial subjects. The aim of the thesis is to reinforce arguments that portray colonial medicine as a “tool of empire” but goes a bit further to explain the extent to which Africans related to this reality. It states quite categorically that Africans were not docile and silent, but that they acted decisively in ways that suited their varied interests and courses.
- Full Text:
- Date Issued: 2019
Ethnic conflict in Nigeria: a challenge to inclusive social and political development
- Authors: Adetiba, Toyin Cotties
- Date: 2013
- Subjects: Genocide -- Nigeria , Ethnic conflict -- Nigeria , National characteristics, Nigerian , Citizenship -- Nigeria , Ethnicity -- Nigeria , Multiculturalism -- Nigeria , Economic development -- Nigeria , Nigeria -- Politics and government , Nationalism -- Nigeria , Nigeria -- Social conditions
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11432 , http://hdl.handle.net/10353/d1006955 , Genocide -- Nigeria , Ethnic conflict -- Nigeria , National characteristics, Nigerian , Citizenship -- Nigeria , Ethnicity -- Nigeria , Multiculturalism -- Nigeria , Economic development -- Nigeria , Nigeria -- Politics and government , Nationalism -- Nigeria , Nigeria -- Social conditions
- Description: The question of ethnicity has been one of the most topical subjects of study by social scientists. The controversies around this phenomenon seem to have been heated up by the high visibility of mobilized and politicized ethnic groups in most multi-ethnic states. Therefore, the extent to which ethnic nationalities are able to effectively manage the interplay of ethnic differences determines to what extent a multi-ethnic nation develops without crisis. Historically Nigeria has come a long way from multi-ethnic entity with political differences and background to the amalgamation of 1914 till the present structure of thirty-six states. Ethnicity, no doubt has contributed immensely to ethnic conflicts in Nigeria because of long standing revulsion or resentments towards ethnic groups different from one’s own or fear of domination which can as well lead ethnic groups to resort to violence as a means to protect and preserve the existing ethnic groups. Significantly ethnicity in Nigeria, is a product inequality among the various ethnic groups orchestrated by a long period of colonialism; a period which witnessed the ascendancy of three major ethnic groups to the socio-political domination of other ethnic groups and a period when the three major ethnic groups were used as a pedestal for the distribution of socio-political goods, resulting in the inability of other ethnic groups to access these socio-political goods. This situation has continued to impact negatively on the forces of national integration and cohesion in ethnically divided Nigeria. Considering the relationship between ethnicity and development; socio-political exclusion is not only ethically dangerous to development but also economically unproductive. It deprives groups and individuals of the opportunity for the necessary development that can be beneficial to the society. Thus, it is important to develop an integrative socio-political frame-work that explicitly recognizes the participatory role of every ethnic group in governance. Hence, there is a need for the adoption of inclusive governance to manage ethnicity in Nigeria. Notwithstanding, ethnic conflict still persists and an attempt will be made in this study to identify the reasons. Central to socio-political sustainability in Nigeria is a system that should recognize that differences are important to development and encompass notions of equality. Such a system should acknowledge the socio-political and economic power of every ethnic group and promote a system devoid of ethnocentric and exclusionary socio-political and economic policies.
- Full Text:
- Date Issued: 2013
- Authors: Adetiba, Toyin Cotties
- Date: 2013
- Subjects: Genocide -- Nigeria , Ethnic conflict -- Nigeria , National characteristics, Nigerian , Citizenship -- Nigeria , Ethnicity -- Nigeria , Multiculturalism -- Nigeria , Economic development -- Nigeria , Nigeria -- Politics and government , Nationalism -- Nigeria , Nigeria -- Social conditions
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11432 , http://hdl.handle.net/10353/d1006955 , Genocide -- Nigeria , Ethnic conflict -- Nigeria , National characteristics, Nigerian , Citizenship -- Nigeria , Ethnicity -- Nigeria , Multiculturalism -- Nigeria , Economic development -- Nigeria , Nigeria -- Politics and government , Nationalism -- Nigeria , Nigeria -- Social conditions
- Description: The question of ethnicity has been one of the most topical subjects of study by social scientists. The controversies around this phenomenon seem to have been heated up by the high visibility of mobilized and politicized ethnic groups in most multi-ethnic states. Therefore, the extent to which ethnic nationalities are able to effectively manage the interplay of ethnic differences determines to what extent a multi-ethnic nation develops without crisis. Historically Nigeria has come a long way from multi-ethnic entity with political differences and background to the amalgamation of 1914 till the present structure of thirty-six states. Ethnicity, no doubt has contributed immensely to ethnic conflicts in Nigeria because of long standing revulsion or resentments towards ethnic groups different from one’s own or fear of domination which can as well lead ethnic groups to resort to violence as a means to protect and preserve the existing ethnic groups. Significantly ethnicity in Nigeria, is a product inequality among the various ethnic groups orchestrated by a long period of colonialism; a period which witnessed the ascendancy of three major ethnic groups to the socio-political domination of other ethnic groups and a period when the three major ethnic groups were used as a pedestal for the distribution of socio-political goods, resulting in the inability of other ethnic groups to access these socio-political goods. This situation has continued to impact negatively on the forces of national integration and cohesion in ethnically divided Nigeria. Considering the relationship between ethnicity and development; socio-political exclusion is not only ethically dangerous to development but also economically unproductive. It deprives groups and individuals of the opportunity for the necessary development that can be beneficial to the society. Thus, it is important to develop an integrative socio-political frame-work that explicitly recognizes the participatory role of every ethnic group in governance. Hence, there is a need for the adoption of inclusive governance to manage ethnicity in Nigeria. Notwithstanding, ethnic conflict still persists and an attempt will be made in this study to identify the reasons. Central to socio-political sustainability in Nigeria is a system that should recognize that differences are important to development and encompass notions of equality. Such a system should acknowledge the socio-political and economic power of every ethnic group and promote a system devoid of ethnocentric and exclusionary socio-political and economic policies.
- Full Text:
- Date Issued: 2013
In vivo toxicological evaluation of peptide conjugated gold nanoparticles for potential application in colorectal cancer diagnosis
- Authors: Adewale, Olusola Bolaji
- Date: 2018
- Subjects: Nanostructured materials -- Toxicology , Colon (Anatomy) -- Cancer Rectum -- Cancer
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50133 , vital:42050
- Description: Colorectal cancer (CRC) is among the leading cause of cancer-related deaths in South Africa and worldwide. Efforts are being made at finding improved diagnostic tools, as early detection (before metastasis) is a major factor in CRC treatment. Colonoscopy is the most reliable detection method, but is a specialised and expensive procedure, which is invasive, not readily available and not patient-friendly. There is a risk of developing interval cancers, as colonoscopies are performed every 10 years after the age of 40. The development of non-invasive, cost efficient and readily available diagnostic tools to CRC, which can be performed at more regular intervals, using tumour-targeting molecular imaging agents, is of urgent attention. Gold nanoparticles (AuNPs) possess several physicochemical properties, including ease of synthesis, biocompatibility, and the ability to be conjugated by ligands or biomolecules such as polyethylene glycol (PEG) and peptides for improved stability, tissue targeting and selectivity. These factors potentiate the role in biomedical applications, including cancer theranostics. Conjugation of AuNPs with a targeting molecule (e.g. antibody or peptide) is directed against cancer cell receptors. The peptides, p.C, p.L, and p.14, bind to CRC cells in vitro. Conjugation of AuNPs with these peptides should be investigated for CRC diagnosis in vivo, as it is hypothesised to allow examinations at shorter intervals through imaging techniques. This could reduce the risk of interval cancers, but before developing this novel tool, in vivo toxicity evaluations are essential. This study was therefore aimed at investigating the short- and long-term toxicological effects of a single intravenous injection of peptides (p.C, p.L, and p.14) conjugated to AuNPs in a healthy rat model. Citrate-capped AuNPs were synthesised by the citrate-reduction method, and conjugated with each peptide (biotinylated) using a combination of PEG (99% PEG-OH and 1% PEG-biotin) as a stabilising agent and linker, via biotin-streptavidin interaction. Healthy male Wistar rats were intravenously injected with 14 nm citrate-AuNPs, PEG-, p.C-PEG, p.L-PEG, and p.14-PEG-AuNPs (100 μg/kg body weight), and the control rats were injected with phosphate buffered saline. The animals were monitored for behavioural, physiological, biochemical, haematological and histological changes, as well as inflammatory responses. Phase 1 rats were sacrificed 2 weeks post-injection to determine the immediate or acute toxicity of the AuNPs, while phase 2 animals were sacrificed 12 weeks post-injection, to investigate the delayed or persistence toxicity of the AuNPs. Results revealed no significant toxicities with the citrate, PEG-, p.C-PEG and p.14-PEG-AuNPs over 12 weeks post-exposure, as evidenced by biochemical assays such as serum marker enzymes, liver and kidney function markers, and cholestatic indicators; haematological parameters; oxidative stress markers; and histopathological examinations. P.L-PEG-AuNPs, however, caused significant toxicity (p<0.05) to rats, as evidenced by increased relative liver weight, increased malondialdehyde levels, and total white blood cell counts 2 weeks post-exposure when compared to the control group. This was, however, reversed during the 12 weeks post-exposure. Further, there were no evidence of inflammatory responses, using pro-inflammatory markers including phospho interleukin 18 (IL-18) and interferon-γ (IFN-γ), as indicated by immunohistochemical staining of the liver, spleen, kidney and colon of rats 2 weeks post-injection of AuNPs. Citrate, PEG-, p.C-PEG, and p.14-PEG-AuNPs did not induce immediate, acute or persistent toxicity, while p.L-PEG-AuNPs induced a transient acute toxicity. It can be concluded that 14 nm spherical citrate-AuNPs at 100 μg/kg body weight is a good candidate for biomedical applications, and as a suitable carrier for diagnostic and/or therapeutic molecules. Combination of 99% PEG-OH and 1% PEG-biotin is an appropriate option for stabilising AuNPs in biological environment, and conjugating secondary diagnostic or therapeutic biomolecules or agents to citrate-capped AuNPs. Peptide-conjugated AuNPs are suitable for the development into a diagnostic tool for CRC in vivo.
- Full Text:
- Date Issued: 2018
- Authors: Adewale, Olusola Bolaji
- Date: 2018
- Subjects: Nanostructured materials -- Toxicology , Colon (Anatomy) -- Cancer Rectum -- Cancer
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50133 , vital:42050
- Description: Colorectal cancer (CRC) is among the leading cause of cancer-related deaths in South Africa and worldwide. Efforts are being made at finding improved diagnostic tools, as early detection (before metastasis) is a major factor in CRC treatment. Colonoscopy is the most reliable detection method, but is a specialised and expensive procedure, which is invasive, not readily available and not patient-friendly. There is a risk of developing interval cancers, as colonoscopies are performed every 10 years after the age of 40. The development of non-invasive, cost efficient and readily available diagnostic tools to CRC, which can be performed at more regular intervals, using tumour-targeting molecular imaging agents, is of urgent attention. Gold nanoparticles (AuNPs) possess several physicochemical properties, including ease of synthesis, biocompatibility, and the ability to be conjugated by ligands or biomolecules such as polyethylene glycol (PEG) and peptides for improved stability, tissue targeting and selectivity. These factors potentiate the role in biomedical applications, including cancer theranostics. Conjugation of AuNPs with a targeting molecule (e.g. antibody or peptide) is directed against cancer cell receptors. The peptides, p.C, p.L, and p.14, bind to CRC cells in vitro. Conjugation of AuNPs with these peptides should be investigated for CRC diagnosis in vivo, as it is hypothesised to allow examinations at shorter intervals through imaging techniques. This could reduce the risk of interval cancers, but before developing this novel tool, in vivo toxicity evaluations are essential. This study was therefore aimed at investigating the short- and long-term toxicological effects of a single intravenous injection of peptides (p.C, p.L, and p.14) conjugated to AuNPs in a healthy rat model. Citrate-capped AuNPs were synthesised by the citrate-reduction method, and conjugated with each peptide (biotinylated) using a combination of PEG (99% PEG-OH and 1% PEG-biotin) as a stabilising agent and linker, via biotin-streptavidin interaction. Healthy male Wistar rats were intravenously injected with 14 nm citrate-AuNPs, PEG-, p.C-PEG, p.L-PEG, and p.14-PEG-AuNPs (100 μg/kg body weight), and the control rats were injected with phosphate buffered saline. The animals were monitored for behavioural, physiological, biochemical, haematological and histological changes, as well as inflammatory responses. Phase 1 rats were sacrificed 2 weeks post-injection to determine the immediate or acute toxicity of the AuNPs, while phase 2 animals were sacrificed 12 weeks post-injection, to investigate the delayed or persistence toxicity of the AuNPs. Results revealed no significant toxicities with the citrate, PEG-, p.C-PEG and p.14-PEG-AuNPs over 12 weeks post-exposure, as evidenced by biochemical assays such as serum marker enzymes, liver and kidney function markers, and cholestatic indicators; haematological parameters; oxidative stress markers; and histopathological examinations. P.L-PEG-AuNPs, however, caused significant toxicity (p<0.05) to rats, as evidenced by increased relative liver weight, increased malondialdehyde levels, and total white blood cell counts 2 weeks post-exposure when compared to the control group. This was, however, reversed during the 12 weeks post-exposure. Further, there were no evidence of inflammatory responses, using pro-inflammatory markers including phospho interleukin 18 (IL-18) and interferon-γ (IFN-γ), as indicated by immunohistochemical staining of the liver, spleen, kidney and colon of rats 2 weeks post-injection of AuNPs. Citrate, PEG-, p.C-PEG, and p.14-PEG-AuNPs did not induce immediate, acute or persistent toxicity, while p.L-PEG-AuNPs induced a transient acute toxicity. It can be concluded that 14 nm spherical citrate-AuNPs at 100 μg/kg body weight is a good candidate for biomedical applications, and as a suitable carrier for diagnostic and/or therapeutic molecules. Combination of 99% PEG-OH and 1% PEG-biotin is an appropriate option for stabilising AuNPs in biological environment, and conjugating secondary diagnostic or therapeutic biomolecules or agents to citrate-capped AuNPs. Peptide-conjugated AuNPs are suitable for the development into a diagnostic tool for CRC in vivo.
- Full Text:
- Date Issued: 2018
The implementation of inclusion policy for learners with special education needs in primary schools in Fort beafort district :Towards a rights based approach to education
- Authors: Adewumi, Toyin Mary
- Date: 2014
- Subjects: Inclusive education Education and state -- South Africa -- Eastern Cape Children with disabilities -- Education -- South Africa -- Eastern Cape Special education -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5873 , vital:29413
- Description: The implementation of inclusion policy for learners with special education needs as stipulated in the Education White Paper 2001has been an issue of concern for South African schools. This study sheds light on the implementation of inclusion policy for learners with special education needs in the selected primary schools in the Fort Beaufort District in the Eastern Cape Province in South Africa. The aim of the study is to examine the implementation of inclusion policy for learners with special education needs. The study was placed within the post-positivism paradigm and used a mixed method research approach that integrated concurrent procedures in the collection, analysis and interpretation of the data. Questionnaires were used to collect quantitative data while qualitative data were collected through interviews, and document analysis. A total number of 30 teachers completed the questionnaires. The researcher conducted interviews with ten principals and eight teachers. She also held interviews with four education district officials and one provincial official. Data were analysed by statistical and non-statistical procedures. The study revealed that the inclusion policy is being implemented in the selected schools. However, there are challenges that are being encountered. Firstly, some teachers have not received adequate training with regards to inclusive education policy. Staff development workshops put in place to address this challenge are minimal, and there is not enough joint effort being established by the different stakeholders with regards to support and monitoring the implementation process. Despite the challenges that accompany implementation of inclusion of learners with special education needs, as well as the difficult working conditions, this study reveals that there are pockets of good practice of inclusion policy in some of the selected schools in the Fort Beaufort District. For instance, it was found that teachers implement inclusion of learners with special education needs, even though the majority of them do not have qualifications in special education. It was also revealed that teachers used learner-centred teaching methods to accommodate all learners, which include group and individual teaching, group demonstration, discussions, question-and-answer sessions, and practical activities.
- Full Text:
- Date Issued: 2014
- Authors: Adewumi, Toyin Mary
- Date: 2014
- Subjects: Inclusive education Education and state -- South Africa -- Eastern Cape Children with disabilities -- Education -- South Africa -- Eastern Cape Special education -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/5873 , vital:29413
- Description: The implementation of inclusion policy for learners with special education needs as stipulated in the Education White Paper 2001has been an issue of concern for South African schools. This study sheds light on the implementation of inclusion policy for learners with special education needs in the selected primary schools in the Fort Beaufort District in the Eastern Cape Province in South Africa. The aim of the study is to examine the implementation of inclusion policy for learners with special education needs. The study was placed within the post-positivism paradigm and used a mixed method research approach that integrated concurrent procedures in the collection, analysis and interpretation of the data. Questionnaires were used to collect quantitative data while qualitative data were collected through interviews, and document analysis. A total number of 30 teachers completed the questionnaires. The researcher conducted interviews with ten principals and eight teachers. She also held interviews with four education district officials and one provincial official. Data were analysed by statistical and non-statistical procedures. The study revealed that the inclusion policy is being implemented in the selected schools. However, there are challenges that are being encountered. Firstly, some teachers have not received adequate training with regards to inclusive education policy. Staff development workshops put in place to address this challenge are minimal, and there is not enough joint effort being established by the different stakeholders with regards to support and monitoring the implementation process. Despite the challenges that accompany implementation of inclusion of learners with special education needs, as well as the difficult working conditions, this study reveals that there are pockets of good practice of inclusion policy in some of the selected schools in the Fort Beaufort District. For instance, it was found that teachers implement inclusion of learners with special education needs, even though the majority of them do not have qualifications in special education. It was also revealed that teachers used learner-centred teaching methods to accommodate all learners, which include group and individual teaching, group demonstration, discussions, question-and-answer sessions, and practical activities.
- Full Text:
- Date Issued: 2014
Synthesis, characterization and evaluation of photophysical and electrochemical properties of ruthenium(II) complexes for dye-sensitized solar cells
- Authors: Adjogri, Shadrack John
- Date: 2018
- Subjects: Ruthenium Ruthenium compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/17828 , vital:41363
- Description: Eight series of thirty (30) novel heteroleptic ruthenium(II) complexes were designed, synthesized and spectroscopically characterized, with the following general molecular formulae as [Ru(bdmpmar)(H2dcbpy)(NCS)]+, [Ru(bdmpmar)(vpdiinp)(H2dcbpy)]2,+, [Ru(bdmpmar)(vpbpp)(H2dcbpy)]2+,[Ru(H2dcbpy)2(N^)(NCS)]+, [Ru(H2dcbpy)2(N^)2]2+, [Ru(H2dcbpy)(N^)2(NCS)2], [Ru(H2dcbpy)(N^)(NCS)3]– and [Ru(vptpy)(H2dcbpy)(N^^^)]2+ where bdmpmar is a tridentate ligand of N,N-bis(3, 5-dimethylpyrazol-1-yl-methyl) aromatic organic compound (such aromatic organic compounds(Ar) are anthranilic acid, 4-methoxy-2-nitroaniline, aniline, toluidine, cyclohexylamine and anisidine), vpdiinp represents a monodentate ligand of 11-(4-vinylphenyl)diindeno[1,2-b:2’,1’-e]pyridine, vpbpp represents a monodentate ligand of 4-(4-vinylphenyl)-2.6-bis(phenyl)pyridine and vptpy represents a tridentate ligand of 4’-(4-vinyl)-2,2’:6’,2’’-terpyridine. Meanwhile, N^ represents any of the monodentate ligands of either vpdiinp or vpbpp and (N^^^) represents any of the monodentate ligands either of vpdiinp or vpbpp or NCS as disclosed in series VIII. The complexes were characterized by conductivity measurement, solubility, melting point, UV-Vis, PL, FTIR (ATR), NMR, Cyclic and square wave voltammetry. Nine chelating ligands, comprising of six (6) tripodal chelating ligands, two (2) vinyl monodentate ligands and one (1) vinyl tridentate ligand, were used for the synthesis of ruthenium(II) complexes ATR-FTIR spectra of all the ruthenium(II) complexes measured as solid samples, exhibited fine resolution IR bands in region between 3473-3438 cm-1 of carboxylic group in H2dcbpy. The bands in the range 3040-2950 cm-1 were ascribed to C-H bond stretching for the CH3 groups. The coordination of NCS group in the sphere of ruthenium(II) complexes related to series I, IV, VI VII and one compound of series VIII was investigated by ATR-FTIR spectroscopy. Bands in the range of 2116-2106 cm-1 and 777-770 cm-1 are ascribed to the respective N=C and the C=S bond stretching vibration which confirms the N-coordination of the SCN group. For all the complexes, the stretching vibration of Ru-N bonding was between 466 and 411 cm-1 due to coordination of the nitrogen atoms of the ligands to ruthenium central metal atom. The introduction of the two vinyl monodentate ligands (vpdiinp and vpbpp) in the coordination sphere of [Ru(bdmpmar)(vpdiinp)(H2dcbpy)]2+, [Ru(bdmpmar) (vpbpp)(H2dcbpy)]2+, [Ru(H2dcbpy)2(N^)(NCS)]+, [Ru(H2dcbpy)2(N^)2]2+, [Ru(H2dcbpy)(N^)2(NCS)2], [Ru(H2dcbpy)(N^)(NCS)3]– and [Ru(vptpy)(H2dcbpy)(N^^^)]2+ respectively, all related to series II, III, IV, V, VI, VII and two compounds of series VIII ruthenium(II) complexes, has been studied using the 1H and 13C NMR spectroscopy techniques. The 1H NMR spectra of series II-VII and the two compounds of series VIII of the ruthenium(II) complexes show multiplets in the aromatic region above 6 ppm due to the presence of either vpdiinp or vpbpp ligand, situated in different magnetic environment. However, no splitting pattern was observed in series I and part of VIII complexes possibly due to the absence vinyl monodentate subunits (vpdiinp and vpbpp) in series I and one of compound in series VIII ruthenium(II) complexes show no signals of complex splitting patterns. Carbon-13 NMR spectra data of series I to VIII ruthenium(II) complexes show most resonance signals range in the aromatic region of (δ 116.54-199.63ppm) corresponding to the molecular formulation of ruthenium(II) complexes incorporating 4,4-dicarboxy-2,2’-bipyridine, bdmpmar, vptpy, vpdiinp or vpbpp and NCS ligands respectively, depending on the intrinsic ligand variations. Carbon-13 NMR spectra data of series I, IV, VI VII and one compound in VIII show resonance peaks within the range 130-135 ppm are ascribed to NCS ligand confirming the presence of N-coordinated thiocyanate. Cyclic voltammograms of series I-IV and VI-VIII complexes display ruthenium-based oxidative peaks and the pyridines ligand-based reductive peaks. The redox behavior of complexes 4-12, 14-16, 18-20, 24-26 and 30 is dominated by the Ru(II)/R(III) redox couple in region (E1/2 between 0.53 and 1.18) and the pyridines ligand-based redox couples in the region between (E1/2 between −0.25 and −1.45). The photophysical property studies of the Ru(II) complexes are determined through the acquisitions of the absorption spectra, which tends to have profound effect on the short circuit current of DSSC. The absorption maxima were tuned by the introduction and variation of six (6) tripodal chelating ligands, two (2) vinyl monodentate ligands and one (1) vinyl tridentate ligand. From the studies, the results show that series IV, V, VI, VII and VIII complexes of molecular formula [Ru(H2dcbpy)2(N^)(NCS)]2+, [Ru(H2dcbpy)2(N^)2]2+, [Ru(H2dcbpy)(N^)2(NCS)2]2+, [Ru(H2dcbpy)(N^)(NCS)3]2+ and [Ru(vptpy)(H2dcbpy)(N^^^)]2+ respectively, have higher and multiple local absorption maxima near-IR region than the complexes of series I, II and III of molecular [Ru(bdmpmar)(H2dcbpy)(NCS)]2,+, [Ru(bdmpmar)(vpdiinp)(H2dcbpy)]2,+, [Ru(bdmpmar)(vpbpp)(H2dcbpy)]2,+respectively.
- Full Text:
- Date Issued: 2018
- Authors: Adjogri, Shadrack John
- Date: 2018
- Subjects: Ruthenium Ruthenium compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/17828 , vital:41363
- Description: Eight series of thirty (30) novel heteroleptic ruthenium(II) complexes were designed, synthesized and spectroscopically characterized, with the following general molecular formulae as [Ru(bdmpmar)(H2dcbpy)(NCS)]+, [Ru(bdmpmar)(vpdiinp)(H2dcbpy)]2,+, [Ru(bdmpmar)(vpbpp)(H2dcbpy)]2+,[Ru(H2dcbpy)2(N^)(NCS)]+, [Ru(H2dcbpy)2(N^)2]2+, [Ru(H2dcbpy)(N^)2(NCS)2], [Ru(H2dcbpy)(N^)(NCS)3]– and [Ru(vptpy)(H2dcbpy)(N^^^)]2+ where bdmpmar is a tridentate ligand of N,N-bis(3, 5-dimethylpyrazol-1-yl-methyl) aromatic organic compound (such aromatic organic compounds(Ar) are anthranilic acid, 4-methoxy-2-nitroaniline, aniline, toluidine, cyclohexylamine and anisidine), vpdiinp represents a monodentate ligand of 11-(4-vinylphenyl)diindeno[1,2-b:2’,1’-e]pyridine, vpbpp represents a monodentate ligand of 4-(4-vinylphenyl)-2.6-bis(phenyl)pyridine and vptpy represents a tridentate ligand of 4’-(4-vinyl)-2,2’:6’,2’’-terpyridine. Meanwhile, N^ represents any of the monodentate ligands of either vpdiinp or vpbpp and (N^^^) represents any of the monodentate ligands either of vpdiinp or vpbpp or NCS as disclosed in series VIII. The complexes were characterized by conductivity measurement, solubility, melting point, UV-Vis, PL, FTIR (ATR), NMR, Cyclic and square wave voltammetry. Nine chelating ligands, comprising of six (6) tripodal chelating ligands, two (2) vinyl monodentate ligands and one (1) vinyl tridentate ligand, were used for the synthesis of ruthenium(II) complexes ATR-FTIR spectra of all the ruthenium(II) complexes measured as solid samples, exhibited fine resolution IR bands in region between 3473-3438 cm-1 of carboxylic group in H2dcbpy. The bands in the range 3040-2950 cm-1 were ascribed to C-H bond stretching for the CH3 groups. The coordination of NCS group in the sphere of ruthenium(II) complexes related to series I, IV, VI VII and one compound of series VIII was investigated by ATR-FTIR spectroscopy. Bands in the range of 2116-2106 cm-1 and 777-770 cm-1 are ascribed to the respective N=C and the C=S bond stretching vibration which confirms the N-coordination of the SCN group. For all the complexes, the stretching vibration of Ru-N bonding was between 466 and 411 cm-1 due to coordination of the nitrogen atoms of the ligands to ruthenium central metal atom. The introduction of the two vinyl monodentate ligands (vpdiinp and vpbpp) in the coordination sphere of [Ru(bdmpmar)(vpdiinp)(H2dcbpy)]2+, [Ru(bdmpmar) (vpbpp)(H2dcbpy)]2+, [Ru(H2dcbpy)2(N^)(NCS)]+, [Ru(H2dcbpy)2(N^)2]2+, [Ru(H2dcbpy)(N^)2(NCS)2], [Ru(H2dcbpy)(N^)(NCS)3]– and [Ru(vptpy)(H2dcbpy)(N^^^)]2+ respectively, all related to series II, III, IV, V, VI, VII and two compounds of series VIII ruthenium(II) complexes, has been studied using the 1H and 13C NMR spectroscopy techniques. The 1H NMR spectra of series II-VII and the two compounds of series VIII of the ruthenium(II) complexes show multiplets in the aromatic region above 6 ppm due to the presence of either vpdiinp or vpbpp ligand, situated in different magnetic environment. However, no splitting pattern was observed in series I and part of VIII complexes possibly due to the absence vinyl monodentate subunits (vpdiinp and vpbpp) in series I and one of compound in series VIII ruthenium(II) complexes show no signals of complex splitting patterns. Carbon-13 NMR spectra data of series I to VIII ruthenium(II) complexes show most resonance signals range in the aromatic region of (δ 116.54-199.63ppm) corresponding to the molecular formulation of ruthenium(II) complexes incorporating 4,4-dicarboxy-2,2’-bipyridine, bdmpmar, vptpy, vpdiinp or vpbpp and NCS ligands respectively, depending on the intrinsic ligand variations. Carbon-13 NMR spectra data of series I, IV, VI VII and one compound in VIII show resonance peaks within the range 130-135 ppm are ascribed to NCS ligand confirming the presence of N-coordinated thiocyanate. Cyclic voltammograms of series I-IV and VI-VIII complexes display ruthenium-based oxidative peaks and the pyridines ligand-based reductive peaks. The redox behavior of complexes 4-12, 14-16, 18-20, 24-26 and 30 is dominated by the Ru(II)/R(III) redox couple in region (E1/2 between 0.53 and 1.18) and the pyridines ligand-based redox couples in the region between (E1/2 between −0.25 and −1.45). The photophysical property studies of the Ru(II) complexes are determined through the acquisitions of the absorption spectra, which tends to have profound effect on the short circuit current of DSSC. The absorption maxima were tuned by the introduction and variation of six (6) tripodal chelating ligands, two (2) vinyl monodentate ligands and one (1) vinyl tridentate ligand. From the studies, the results show that series IV, V, VI, VII and VIII complexes of molecular formula [Ru(H2dcbpy)2(N^)(NCS)]2+, [Ru(H2dcbpy)2(N^)2]2+, [Ru(H2dcbpy)(N^)2(NCS)2]2+, [Ru(H2dcbpy)(N^)(NCS)3]2+ and [Ru(vptpy)(H2dcbpy)(N^^^)]2+ respectively, have higher and multiple local absorption maxima near-IR region than the complexes of series I, II and III of molecular [Ru(bdmpmar)(H2dcbpy)(NCS)]2,+, [Ru(bdmpmar)(vpdiinp)(H2dcbpy)]2,+, [Ru(bdmpmar)(vpbpp)(H2dcbpy)]2,+respectively.
- Full Text:
- Date Issued: 2018
Learning styles, availability, and utilization of instructional materials as correlates of grade 6 learners’ mathematics performance in Buffalo city
- Authors: Adu, Kemi Olajumoke
- Date: 2020
- Subjects: Learning ability
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/11374 , vital:39066
- Description: Mathematics is the foundation for the economic and technological development of any nation. It has been asserted that Mathematics is expected to help in accelerating social, economic and technological progress of any society. Performance of this subject is very important and there are different types of learners; such auditory, visual, and kinesthetic. Auditory learners appreciate listening to the teachers and sit down close to the teachers in class. Visual learners like to see things physically during teaching. They learn by materials like charts, graphs, and pictures. Kinesthetic learners learn by doing. Students can prefer one, two, or three learning styles; all these are subject to the availability of instructional materials. The Primary school level is very important in any educational system and any lack at this level would permeate to other levels of the educational system. Hence, this thesis examines the Learning Styles, Availability, and Utilization of Instructional Materials as Correlates of Grade 6 Learners’ Mathematics Performance in Buffalo City. The study adopted the positivist paradigm and employed the quantitative approach in investigating the phenomenon. The thesis made use of correlational research design as it attempted to find out the effects of learning styles and instructional materials on learners’ performance in Mathematics. Stratified sampling was used to select participants. Stratified sampling is a process of dividing the sample frame into strata to obtain relatively homogenous subgroups; this gave us 1225 Grade 6 learners selected across 35 schools in Buffalo City as the sample of the study. Three instruments which are Students’ Learning Styles Scale (SLSS), Availability and Utilization of Instructional Materials Inventory (AUIMI), and Mathematics Achievement Test (MAT) whose reliability co-efficient are; 0.87, 0.78 and 0.89 respectively. The data collected were analysed using descriptive and inferential statistics. The findings of the study revealed among others; students learning style (visual, auditory, and kinesthetic) have a significant relationship on Grade 6 learners Mathematics performance (B=-.113, t=-3.886, p<0.05). Students learning style (∆R2=.012, ∆F (1, 1223) = 5.047, p < 0.05) emerged as the best predictor of Grade 6 learners Mathematics performance in Buffalo City, while the availability and utilization of instructional materials (∆R2 = .000), ∆F (1,223) = .018, P > 0.05), and gender (∆R2 = .000, ∆F (1,1223) = .036, p>0.05) emerged as better predictors. The study further iv revealed that, Grade six learners with visual learning style ( = 13.242, SD = 5.565) had the best performance in Mathematics at Buffalo City, followed by learners with auditory learning style ( = 12.996, SD = 3.883), and learners with Kinaesthetic learning style ( = 11.525, SD =3.800). The study concluded that one of the most fundamental issues to consider in improving Mathematics performance is the understanding of the learners’ learning styles and effective use of appropriate instructional materials for teaching Mathematics.
- Full Text:
- Date Issued: 2020
- Authors: Adu, Kemi Olajumoke
- Date: 2020
- Subjects: Learning ability
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/11374 , vital:39066
- Description: Mathematics is the foundation for the economic and technological development of any nation. It has been asserted that Mathematics is expected to help in accelerating social, economic and technological progress of any society. Performance of this subject is very important and there are different types of learners; such auditory, visual, and kinesthetic. Auditory learners appreciate listening to the teachers and sit down close to the teachers in class. Visual learners like to see things physically during teaching. They learn by materials like charts, graphs, and pictures. Kinesthetic learners learn by doing. Students can prefer one, two, or three learning styles; all these are subject to the availability of instructional materials. The Primary school level is very important in any educational system and any lack at this level would permeate to other levels of the educational system. Hence, this thesis examines the Learning Styles, Availability, and Utilization of Instructional Materials as Correlates of Grade 6 Learners’ Mathematics Performance in Buffalo City. The study adopted the positivist paradigm and employed the quantitative approach in investigating the phenomenon. The thesis made use of correlational research design as it attempted to find out the effects of learning styles and instructional materials on learners’ performance in Mathematics. Stratified sampling was used to select participants. Stratified sampling is a process of dividing the sample frame into strata to obtain relatively homogenous subgroups; this gave us 1225 Grade 6 learners selected across 35 schools in Buffalo City as the sample of the study. Three instruments which are Students’ Learning Styles Scale (SLSS), Availability and Utilization of Instructional Materials Inventory (AUIMI), and Mathematics Achievement Test (MAT) whose reliability co-efficient are; 0.87, 0.78 and 0.89 respectively. The data collected were analysed using descriptive and inferential statistics. The findings of the study revealed among others; students learning style (visual, auditory, and kinesthetic) have a significant relationship on Grade 6 learners Mathematics performance (B=-.113, t=-3.886, p<0.05). Students learning style (∆R2=.012, ∆F (1, 1223) = 5.047, p < 0.05) emerged as the best predictor of Grade 6 learners Mathematics performance in Buffalo City, while the availability and utilization of instructional materials (∆R2 = .000), ∆F (1,223) = .018, P > 0.05), and gender (∆R2 = .000, ∆F (1,1223) = .036, p>0.05) emerged as better predictors. The study further iv revealed that, Grade six learners with visual learning style ( = 13.242, SD = 5.565) had the best performance in Mathematics at Buffalo City, followed by learners with auditory learning style ( = 12.996, SD = 3.883), and learners with Kinaesthetic learning style ( = 11.525, SD =3.800). The study concluded that one of the most fundamental issues to consider in improving Mathematics performance is the understanding of the learners’ learning styles and effective use of appropriate instructional materials for teaching Mathematics.
- Full Text:
- Date Issued: 2020
Incidence of porcine circovirus type 2 and porcine parvoviruses in swine herds of some communities in Eastern Cape, South Africa
- Authors: Afolabi, Kayode Olayinka
- Date: 2018
- Subjects: Swine -- Diseases Swine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9691 , vital:34820
- Description: Porcine circovirus type 2 (PCV2) is one of the swine pathogens of global economic importance. Since its first detection in early 1990s as the main etiologic agent of porcine multisystemic wasting syndrome (PMWS) and many other porcine circovirus-associated diseases (PCVAD), the virus has been extensively studied and has been found to be present in virtually all the pig producing countries of the world. As a viral pathogen that brings about clinical diseases aided by co-infecting pathogens, the involvement of many other viral agents including porcine parvoviruses (PPVs) have caught the attention of stakeholders worldwide. However, no surveillance study of the viral pathogens has been carried out in South Africa as there are little or no information on their prevalence in the swine herds of the country. This present study therefore aimed at detection and molecular characterization of PCV2 and PPVs in swine herds of some selected communities in Eastern Cape Province, South Africa. A total of 375 field samples were collected from seven commercial and communal farms from three District Municipalities of Eastern Cape, South Africa between 2015 and 2016. Structured questionnaires were also administered to each farm at the time of sample collection to obtain some important information relating to health status and farm management practices in the sampled farms. With the aid of conventional PCR method, 339 samples were initially screened for the presence of PCV2; positive amplicons were sequenced and obtained partial genomes of the virus were preliminarily analyzed. In order to obtain the complete genomes of the virus, four overlapping primer pairs were used to amplify the full-genome of PCV2 from the initial positive samples; amplified genomes were sequenced using the Sanger methods, sequenced PCV2 genomes were assembled and characterized. Furthermore, the prevalences of some designated PPVs in the sampled farms were obtained using 110 samples randomly selected from the previously archived samples and screened with 6 different primer pairs specific for the detection of 7 PPVs. All the amplified parvoviruses’ genomes were sequenced; their sequenced partial genomes were subsequently base-culled and analysed. The data obtained revealed that 54/339 (15.93 percent) samples from the swine herds were positive for PCV2; whereas the degree of occurrence of the viral pathogen as observed at farm level ranges from approximately 5.6 to 60 percent. The majority 15/17 (88 percent) of the analyzed partial sequences were found clustering with other PCV2b strains in the phylogenetic analysis. More interestingly, two other sequences obtained were also found clustering within PCV2d genotype in the initial screening and analysis. Furthermore, 15 complete PCV2 genomes were successfully amplified, sequenced and assembled. NJ and ML phylogenetic analysis of the complete ORF2 gene and full genomes unanimously showed 11 of the assembled genomes belonging to genotype PCV2b. Another 3 of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (PCV2d) strains from different parts of the world. The last sequence however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2-IM2) recently identified in a global PCV2 strains phylogenetic analysis. Other genetic analyses including multiple sequence alignment and p-distance analysis also confirmed the outcomes of the phylogenetic analyses of the complete capsid gene and fullgenomes of the virus. On the other hand, the findings of the molecular profiling for PPVs showed that all the screened parvoviruses were present in the study area, having prevalence of 29.1 percent (PPV1), 21.8 percent (PPV2), 5.5 percent (PPV3), 43.6 percent (PPV4), 21.8 percent (PBo-likeV) and 44.6 percent for PBoV1 and PBoV2. Double infection of the screened PPVs was observed to be very rampant among the pigs as high as 20/110 (18.2 percent) for PPV2/PPV4 and PPV4/PBoV; followed by 19/110 (17.3 percent) of the samples for PPV1/PPV4 and PPV1/PBoV. Three of the viruses were found simultaneously in 19 of the screened samples representing 17.3 percent, whereas 8 (7.3 percent) samples were positive for four of the viruses. Phylogenetic analyses of PPV1, PPV2 and PBoVs 1 and 2 were conducted with two major clades homologous for each of them. This is the first report of PCV2 in swine herds of the Province and the first detection of PCV2b, PCV2d and PCV2-IM2 strains in South African swine herds. It follows the first reported case of PCV2a in an outbreak of porcine multisystemic wasting syndrome (PMWS) in Gauteng Province, South Africa over two decades ago. Also, this is the first major epidemiologic study on PPVs in the country following the initial case study of 1975. These findings confirmed the presence of the allimportant viral pathogens among pigs and also give preliminary insights into the possibility of co-infections of the pathogens in the studied area. This could however result in a serious large scale outbreak of devastating disease(s) associated with the viral pathogens, thereby ultimately resulting in huge economic losses if no appropriate measures are taken to effectively curb their spread across the country.
- Full Text:
- Date Issued: 2018
- Authors: Afolabi, Kayode Olayinka
- Date: 2018
- Subjects: Swine -- Diseases Swine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9691 , vital:34820
- Description: Porcine circovirus type 2 (PCV2) is one of the swine pathogens of global economic importance. Since its first detection in early 1990s as the main etiologic agent of porcine multisystemic wasting syndrome (PMWS) and many other porcine circovirus-associated diseases (PCVAD), the virus has been extensively studied and has been found to be present in virtually all the pig producing countries of the world. As a viral pathogen that brings about clinical diseases aided by co-infecting pathogens, the involvement of many other viral agents including porcine parvoviruses (PPVs) have caught the attention of stakeholders worldwide. However, no surveillance study of the viral pathogens has been carried out in South Africa as there are little or no information on their prevalence in the swine herds of the country. This present study therefore aimed at detection and molecular characterization of PCV2 and PPVs in swine herds of some selected communities in Eastern Cape Province, South Africa. A total of 375 field samples were collected from seven commercial and communal farms from three District Municipalities of Eastern Cape, South Africa between 2015 and 2016. Structured questionnaires were also administered to each farm at the time of sample collection to obtain some important information relating to health status and farm management practices in the sampled farms. With the aid of conventional PCR method, 339 samples were initially screened for the presence of PCV2; positive amplicons were sequenced and obtained partial genomes of the virus were preliminarily analyzed. In order to obtain the complete genomes of the virus, four overlapping primer pairs were used to amplify the full-genome of PCV2 from the initial positive samples; amplified genomes were sequenced using the Sanger methods, sequenced PCV2 genomes were assembled and characterized. Furthermore, the prevalences of some designated PPVs in the sampled farms were obtained using 110 samples randomly selected from the previously archived samples and screened with 6 different primer pairs specific for the detection of 7 PPVs. All the amplified parvoviruses’ genomes were sequenced; their sequenced partial genomes were subsequently base-culled and analysed. The data obtained revealed that 54/339 (15.93 percent) samples from the swine herds were positive for PCV2; whereas the degree of occurrence of the viral pathogen as observed at farm level ranges from approximately 5.6 to 60 percent. The majority 15/17 (88 percent) of the analyzed partial sequences were found clustering with other PCV2b strains in the phylogenetic analysis. More interestingly, two other sequences obtained were also found clustering within PCV2d genotype in the initial screening and analysis. Furthermore, 15 complete PCV2 genomes were successfully amplified, sequenced and assembled. NJ and ML phylogenetic analysis of the complete ORF2 gene and full genomes unanimously showed 11 of the assembled genomes belonging to genotype PCV2b. Another 3 of the characterized sequences formed clade with other reference mutant PCV2b and PCV2b subtype 1C (PCV2d) strains from different parts of the world. The last sequence however, clustered with other reference strains belonging to PCV2 intermediate clade 2 (PCV2-IM2) recently identified in a global PCV2 strains phylogenetic analysis. Other genetic analyses including multiple sequence alignment and p-distance analysis also confirmed the outcomes of the phylogenetic analyses of the complete capsid gene and fullgenomes of the virus. On the other hand, the findings of the molecular profiling for PPVs showed that all the screened parvoviruses were present in the study area, having prevalence of 29.1 percent (PPV1), 21.8 percent (PPV2), 5.5 percent (PPV3), 43.6 percent (PPV4), 21.8 percent (PBo-likeV) and 44.6 percent for PBoV1 and PBoV2. Double infection of the screened PPVs was observed to be very rampant among the pigs as high as 20/110 (18.2 percent) for PPV2/PPV4 and PPV4/PBoV; followed by 19/110 (17.3 percent) of the samples for PPV1/PPV4 and PPV1/PBoV. Three of the viruses were found simultaneously in 19 of the screened samples representing 17.3 percent, whereas 8 (7.3 percent) samples were positive for four of the viruses. Phylogenetic analyses of PPV1, PPV2 and PBoVs 1 and 2 were conducted with two major clades homologous for each of them. This is the first report of PCV2 in swine herds of the Province and the first detection of PCV2b, PCV2d and PCV2-IM2 strains in South African swine herds. It follows the first reported case of PCV2a in an outbreak of porcine multisystemic wasting syndrome (PMWS) in Gauteng Province, South Africa over two decades ago. Also, this is the first major epidemiologic study on PPVs in the country following the initial case study of 1975. These findings confirmed the presence of the allimportant viral pathogens among pigs and also give preliminary insights into the possibility of co-infections of the pathogens in the studied area. This could however result in a serious large scale outbreak of devastating disease(s) associated with the viral pathogens, thereby ultimately resulting in huge economic losses if no appropriate measures are taken to effectively curb their spread across the country.
- Full Text:
- Date Issued: 2018
The design, synthesis and antiplasmodial activity of a series of halogenated fosmidomycin analogues and hybrid drugs
- Authors: Afolayan, Anthonia Folake
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64370 , vital:28538
- Description: Malaria continues to be a devastating disease and a major cause of death in sub-Saharan Africa. With resistance against most of the available antimalarial drugs, there is a need for ongoing research and development of antimalarial agents. Fosmidomycin and its acetyl analogue FR900098 have been identified as potent inhibitors of Plasmodium falciparum, the causative agent of the most deadly form of malaria. Clinical trials of these agents have revealed poor absorption due to their high hydrophilicity. In the present studies the effect of halogenation of the acyl chain as well as the biological effect of extending the acyl sidechain was explored. This provided the basis on which fosmidomycin hybrids were designed to investigate the feasibility of hybrid extending into NADPH binding pocket. Synthesis of a series of halogenated FR900098 analogues was carried out in three stages. This included i) The introduction of the phosphonate group by reaction with 1,3dibromopropane in an Arbuzov reaction, ii) The introduction of a hydroxamate group by reaction of the propyl phosphonate by means of a nucleophilic substitution reaction with BocNHOBn and iii) The introduction of a halogenated acyl side chain on a protected fosmidomycin backbone. The synthesis of fosmidomycin-hybrids for which chloroquinefosmidomycin hybrids were used as the prototype, involved convergence of the two separately constructed moieties i.e. fosmidomycin and the quinoline moieties in a covalent linkage. The quinoline moiety was easily synthesized from the reaction of 4,7dichloroquinoline with 1,2-diamino ethane. The aminoquinoline so formed resulted in chloroquine-fosmidomycin hybrids 3.8 and 3.9 when reacted with halogenated FR900098 analogues. Antiplasmodial assays were conducted on the chloroquine-fosmidomycin hybrids and the halogenated fosmidomycin derivatives against the chloroquine resistant Gambian FCR-3 strain of P. falciparum. The most potent iodoacetyl fosmidomycin analogues 2.21 gave an IC50 value of 5.54 µM which is eight times more potent than the known antiplasmodial FR900098 which gave an IC50 value of 41.67 µM. All the halogenated FR900098 analogues showed better antiplasmodial activity than their non-halogenated derivatives. This indicated that the presence of halogens in the FR900098 analogues contributes to their biological Chapter 1 Literature review activity. The acetyl and propyl linked hybrids 3.8 and 3.9 showed potent antiplasmodial activity with IC50 values of 0.18 and 0.82 µM respectively. These were by far the most potent hybrids synthesized and provided leads for a new class of promising antimalarial agents. Preliminary E. coli DXR enzyme inhibition assays were carried out on the halogenated fosmidomycin analogues. The results showed good inhibition of the enzyme by the phosphonic acids of the chloroacetyl and chloropropyl analogues 2.1 and 2.2 respectively. Molecular modelling of the compounds on E. coli (PDB code: 2EGH) and P. falciparum (PDB code: 3AUA) DXR showed strong binding of the halogenated fosmidomycin analogues while the hybrids in the absence of docked NADPH showed minimum binding to the enzymes.
- Full Text:
- Date Issued: 2012
- Authors: Afolayan, Anthonia Folake
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64370 , vital:28538
- Description: Malaria continues to be a devastating disease and a major cause of death in sub-Saharan Africa. With resistance against most of the available antimalarial drugs, there is a need for ongoing research and development of antimalarial agents. Fosmidomycin and its acetyl analogue FR900098 have been identified as potent inhibitors of Plasmodium falciparum, the causative agent of the most deadly form of malaria. Clinical trials of these agents have revealed poor absorption due to their high hydrophilicity. In the present studies the effect of halogenation of the acyl chain as well as the biological effect of extending the acyl sidechain was explored. This provided the basis on which fosmidomycin hybrids were designed to investigate the feasibility of hybrid extending into NADPH binding pocket. Synthesis of a series of halogenated FR900098 analogues was carried out in three stages. This included i) The introduction of the phosphonate group by reaction with 1,3dibromopropane in an Arbuzov reaction, ii) The introduction of a hydroxamate group by reaction of the propyl phosphonate by means of a nucleophilic substitution reaction with BocNHOBn and iii) The introduction of a halogenated acyl side chain on a protected fosmidomycin backbone. The synthesis of fosmidomycin-hybrids for which chloroquinefosmidomycin hybrids were used as the prototype, involved convergence of the two separately constructed moieties i.e. fosmidomycin and the quinoline moieties in a covalent linkage. The quinoline moiety was easily synthesized from the reaction of 4,7dichloroquinoline with 1,2-diamino ethane. The aminoquinoline so formed resulted in chloroquine-fosmidomycin hybrids 3.8 and 3.9 when reacted with halogenated FR900098 analogues. Antiplasmodial assays were conducted on the chloroquine-fosmidomycin hybrids and the halogenated fosmidomycin derivatives against the chloroquine resistant Gambian FCR-3 strain of P. falciparum. The most potent iodoacetyl fosmidomycin analogues 2.21 gave an IC50 value of 5.54 µM which is eight times more potent than the known antiplasmodial FR900098 which gave an IC50 value of 41.67 µM. All the halogenated FR900098 analogues showed better antiplasmodial activity than their non-halogenated derivatives. This indicated that the presence of halogens in the FR900098 analogues contributes to their biological Chapter 1 Literature review activity. The acetyl and propyl linked hybrids 3.8 and 3.9 showed potent antiplasmodial activity with IC50 values of 0.18 and 0.82 µM respectively. These were by far the most potent hybrids synthesized and provided leads for a new class of promising antimalarial agents. Preliminary E. coli DXR enzyme inhibition assays were carried out on the halogenated fosmidomycin analogues. The results showed good inhibition of the enzyme by the phosphonic acids of the chloroacetyl and chloropropyl analogues 2.1 and 2.2 respectively. Molecular modelling of the compounds on E. coli (PDB code: 2EGH) and P. falciparum (PDB code: 3AUA) DXR showed strong binding of the halogenated fosmidomycin analogues while the hybrids in the absence of docked NADPH showed minimum binding to the enzymes.
- Full Text:
- Date Issued: 2012
A morphogenic and laminated system explanation of position-practice systems and professional development training in mainstreaming education for sustainable development in African universities
- Authors: Agbedahin, Adesuwa Vanessa
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/584 , vital:19972
- Description: This research focuses on Education for Sustainable Development (ESD) in Higher Education Institutions (HEIs), particularly in Africa. It explores the roles and practices of these institutions, especially their professionals, in the Anthropocene era where increasing concern for contemporary environmental and sustainability issues and risks emerge. The study presents a longitudinal case study of institutions and participants of the Swedish/African/Asian International Training Programme (ITP) on ESD in Higher Education (HE), who are mostly university educators. This thesis however focuses on African ITP participants only. At a macro level, the research sought to examine how African university educators have contributed to the United Nations Decade of Education for Sustainable Development (UNDESD) through their participation in the ITP (which is a change oriented professional development training programme on ESD) and the associated ESD ‘change projects’. The change projects are ITP participants’ direct attempts to mainstream environment and sustainability issues, concerns, and concepts into core university functions and practices: teaching, research, community engagement, and management operations and policy engagement. At a meso level the study sought insight into how educators in national institutions were supported by sub-regional and regional initiatives, institutions and organisations, including the Mainstreaming of Environment and Sustainability in African (MESA) Universities Partnership programme, especially an initiative supported by the Southern African Development Community Regional Environmental Education Programme to provide (limited) seed funding to three southern African universities to establish what are known as ‘MESA Chairs’, with dedicated time and support for MESA activities in their universities . At a micro level, this research sought to investigate how the position-practice systems and the ITP shape (enable or constrain) effective ESD mainstreaming in higher education, and how the morphogenetic approach and laminated system can be used to understand and explain these dynamics and their relations with meso and macro level engagements. The research sought to understand these dynamics through empirical investigations using survey questionnaires, interviews, document analysis and field visits. The research is constituted as theoretical, conceptual, methodological and analytical exploration using a singular and nested case study research approach, underlaboured by a critical realist ontology, and drawing on a social learning epistemology and social realist morphogenetic interpretive lens. In particular, ontological depth was sought via critical realist laminated system explanation. See Chapter Two for details. This study was carried out in three phases. Phase one encapsulates the investigation of all ITP ESD in higher education alumni who were Asian and African participants from the inception of the ITP to its completion, over a six-year period (2008-2013). This included 280 academics from Asia and Africa in 35 countries in Asia and Africa from 106 institutions in Asia and Africa with their 139 change projects. The outcome of phase one of the research is only included in this thesis as an appendix (see Appendix 3; Agbedahin & Lotz-Sisitka, 2015). However, this phase provided and formed the foundational data that was expanded in phases two and three for the purpose of this study. Phase two of this research concentrated on a less broad population of research participants comprising only all African ITP alumni, from all regions in Africa. The overall data collection and analysis included 162 academics in 23 African countries from 66 institutions with their 81 change projects. The aim was to investigate and provide a morphogenetic explanation of their change projects and how the relationship between participants’ positions and practices (and that of others) may influence ESD mainstreaming in universities. The outcome of this phase two investigation is presented in Chapter Four. In phase three, (nested) case studies of Swaziland, Zambia, and Botswana (in the southern Africa region), which included all the ESD ITP HE participants therein and the three corresponding EE/ESD MESA Chairs, were developed. The population sample in this phase three therefore contained 20 academics, from six institutions with their nine change projects. This phase was characterised by field trips to these countries and in-depth data collection and analysis in order to investigate and deepen the morphogenetic explanations of their change projects and how the relationship between participants’ positions and practices (and that of others) have indeed influenced the ESD mainstreaming in universities. The outcome of this phase three research is presented in Chapters Five, Six and Seven. The final Chapter Eight of this thesis focuses on the seven scalar laminated system perspective and reflections on this research and discussion of these perspectives for supporting the mainstreaming of ESD in African higher education institutions and more specifically in the three case countries and respective institutions presented in Chapters Five, Six, and Seven. The seven scalar laminated system is presented in relation to the position-practice system, and draws on morphogenetic social realist and social learning theory to provide perspective on the actual change processes. Chapter Eight also includes a discussion on social learning and its implication for ESD mainstreaming, and provides recommendations for further research. The outcome of the theoretical exploration underpinning this study provided a potential model for understanding ESD learning and change processes that are facilitated by professional development training programmes in the context of ESD in HE. This study also provides a model for appraising educational changes in time and in space, especially in relation to ESD, or the types of changes that can be brought about by professional development interventions such as those provided by the ITP and how they can be tracked, monitored and documented. For the field of professional or academic development in higher education, this research highlights the significance of the relationship between position-practice systems, professional development interventions and institutional transformation. For the field of ESD in higher education, this study shows the need for in-depth consideration of the position-practice system and sphere of influence of change agents and related stakeholders in and around their institutions in the design and development of professional development programmes. It further sheds light on the laminated system of factors that contextually constrain and/or enable effective ESD mainstreaming at individual, collective, institutional, national, regional and global levels.
- Full Text:
- Date Issued: 2016
- Authors: Agbedahin, Adesuwa Vanessa
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/584 , vital:19972
- Description: This research focuses on Education for Sustainable Development (ESD) in Higher Education Institutions (HEIs), particularly in Africa. It explores the roles and practices of these institutions, especially their professionals, in the Anthropocene era where increasing concern for contemporary environmental and sustainability issues and risks emerge. The study presents a longitudinal case study of institutions and participants of the Swedish/African/Asian International Training Programme (ITP) on ESD in Higher Education (HE), who are mostly university educators. This thesis however focuses on African ITP participants only. At a macro level, the research sought to examine how African university educators have contributed to the United Nations Decade of Education for Sustainable Development (UNDESD) through their participation in the ITP (which is a change oriented professional development training programme on ESD) and the associated ESD ‘change projects’. The change projects are ITP participants’ direct attempts to mainstream environment and sustainability issues, concerns, and concepts into core university functions and practices: teaching, research, community engagement, and management operations and policy engagement. At a meso level the study sought insight into how educators in national institutions were supported by sub-regional and regional initiatives, institutions and organisations, including the Mainstreaming of Environment and Sustainability in African (MESA) Universities Partnership programme, especially an initiative supported by the Southern African Development Community Regional Environmental Education Programme to provide (limited) seed funding to three southern African universities to establish what are known as ‘MESA Chairs’, with dedicated time and support for MESA activities in their universities . At a micro level, this research sought to investigate how the position-practice systems and the ITP shape (enable or constrain) effective ESD mainstreaming in higher education, and how the morphogenetic approach and laminated system can be used to understand and explain these dynamics and their relations with meso and macro level engagements. The research sought to understand these dynamics through empirical investigations using survey questionnaires, interviews, document analysis and field visits. The research is constituted as theoretical, conceptual, methodological and analytical exploration using a singular and nested case study research approach, underlaboured by a critical realist ontology, and drawing on a social learning epistemology and social realist morphogenetic interpretive lens. In particular, ontological depth was sought via critical realist laminated system explanation. See Chapter Two for details. This study was carried out in three phases. Phase one encapsulates the investigation of all ITP ESD in higher education alumni who were Asian and African participants from the inception of the ITP to its completion, over a six-year period (2008-2013). This included 280 academics from Asia and Africa in 35 countries in Asia and Africa from 106 institutions in Asia and Africa with their 139 change projects. The outcome of phase one of the research is only included in this thesis as an appendix (see Appendix 3; Agbedahin & Lotz-Sisitka, 2015). However, this phase provided and formed the foundational data that was expanded in phases two and three for the purpose of this study. Phase two of this research concentrated on a less broad population of research participants comprising only all African ITP alumni, from all regions in Africa. The overall data collection and analysis included 162 academics in 23 African countries from 66 institutions with their 81 change projects. The aim was to investigate and provide a morphogenetic explanation of their change projects and how the relationship between participants’ positions and practices (and that of others) may influence ESD mainstreaming in universities. The outcome of this phase two investigation is presented in Chapter Four. In phase three, (nested) case studies of Swaziland, Zambia, and Botswana (in the southern Africa region), which included all the ESD ITP HE participants therein and the three corresponding EE/ESD MESA Chairs, were developed. The population sample in this phase three therefore contained 20 academics, from six institutions with their nine change projects. This phase was characterised by field trips to these countries and in-depth data collection and analysis in order to investigate and deepen the morphogenetic explanations of their change projects and how the relationship between participants’ positions and practices (and that of others) have indeed influenced the ESD mainstreaming in universities. The outcome of this phase three research is presented in Chapters Five, Six and Seven. The final Chapter Eight of this thesis focuses on the seven scalar laminated system perspective and reflections on this research and discussion of these perspectives for supporting the mainstreaming of ESD in African higher education institutions and more specifically in the three case countries and respective institutions presented in Chapters Five, Six, and Seven. The seven scalar laminated system is presented in relation to the position-practice system, and draws on morphogenetic social realist and social learning theory to provide perspective on the actual change processes. Chapter Eight also includes a discussion on social learning and its implication for ESD mainstreaming, and provides recommendations for further research. The outcome of the theoretical exploration underpinning this study provided a potential model for understanding ESD learning and change processes that are facilitated by professional development training programmes in the context of ESD in HE. This study also provides a model for appraising educational changes in time and in space, especially in relation to ESD, or the types of changes that can be brought about by professional development interventions such as those provided by the ITP and how they can be tracked, monitored and documented. For the field of professional or academic development in higher education, this research highlights the significance of the relationship between position-practice systems, professional development interventions and institutional transformation. For the field of ESD in higher education, this study shows the need for in-depth consideration of the position-practice system and sphere of influence of change agents and related stakeholders in and around their institutions in the design and development of professional development programmes. It further sheds light on the laminated system of factors that contextually constrain and/or enable effective ESD mainstreaming at individual, collective, institutional, national, regional and global levels.
- Full Text:
- Date Issued: 2016
Young veterans, not always social misfits: a sociological discourse of Liberian transmogrification experiences
- Authors: Agbedahin, Komlan
- Date: 2012
- Subjects: Child soldiers -- Liberia Children and war -- Liberia Liberia. Armed Forces -- Demobilization -- Social aspects Liberia -- History -- Civil War, 1989-1996 Liberia -- History -- Civil War, 1999-2003
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3316 , http://hdl.handle.net/10962/d1003104
- Description: This thesis examines the phenomenon of child-soldiering from a different perspective. It seeks to challenge, using a novel approach, earlier studies on the roles of former child-soldiers in post-war societies. It focuses on the subjectivity of young veterans, that is war veterans formerly associated with armed forces and groups as children during the 14-year gruesome civil war which bedevilled Liberia between 1989 and 2003. This civil war claimed roughly 250,000 lives, and saw the active participation of approximately 21,000 child-soldiers. This thesis departs from previous works which mostly painted an apocalyptic picture of young veterans, and explores the nexus between their self-agency, Foucauldian technologies of the self and their transformation in the post-war society. The majority of previous scholarly works which have dominated the field of child-soldiering dwelt on the impact of armed conflict on the child-soldiers, the negative consequences, the causes of child-soldiering, and the rehabilitation and reintegration of the young veterans after their disarmament and demobilization. What this thesis seeks to do however, is to establish that, rather than considering the young veterans simply as social misfits, distraught and dispirited human beings, it should be noted that young veterans through their agency, are capable of ensuring their reintegration into their war-ravaged societies. Sadly, these young former fighters’ self-agency and technologies of the self in defining their civilian trajectories have often been overshadowed by vaunted humanitarian aid and multilayered war-profiteering. This study is underpinned by interpretive constructivism, symbolic interactionism, social identity theory, sociometer theory and expectancy theory, and sheds light on how young veterans’ self-agency, instrumental coalitions, and decision-making processes, synergistically shifted the negative identities foisted on them as a result of their participation in the war.
- Full Text:
- Date Issued: 2012
- Authors: Agbedahin, Komlan
- Date: 2012
- Subjects: Child soldiers -- Liberia Children and war -- Liberia Liberia. Armed Forces -- Demobilization -- Social aspects Liberia -- History -- Civil War, 1989-1996 Liberia -- History -- Civil War, 1999-2003
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3316 , http://hdl.handle.net/10962/d1003104
- Description: This thesis examines the phenomenon of child-soldiering from a different perspective. It seeks to challenge, using a novel approach, earlier studies on the roles of former child-soldiers in post-war societies. It focuses on the subjectivity of young veterans, that is war veterans formerly associated with armed forces and groups as children during the 14-year gruesome civil war which bedevilled Liberia between 1989 and 2003. This civil war claimed roughly 250,000 lives, and saw the active participation of approximately 21,000 child-soldiers. This thesis departs from previous works which mostly painted an apocalyptic picture of young veterans, and explores the nexus between their self-agency, Foucauldian technologies of the self and their transformation in the post-war society. The majority of previous scholarly works which have dominated the field of child-soldiering dwelt on the impact of armed conflict on the child-soldiers, the negative consequences, the causes of child-soldiering, and the rehabilitation and reintegration of the young veterans after their disarmament and demobilization. What this thesis seeks to do however, is to establish that, rather than considering the young veterans simply as social misfits, distraught and dispirited human beings, it should be noted that young veterans through their agency, are capable of ensuring their reintegration into their war-ravaged societies. Sadly, these young former fighters’ self-agency and technologies of the self in defining their civilian trajectories have often been overshadowed by vaunted humanitarian aid and multilayered war-profiteering. This study is underpinned by interpretive constructivism, symbolic interactionism, social identity theory, sociometer theory and expectancy theory, and sheds light on how young veterans’ self-agency, instrumental coalitions, and decision-making processes, synergistically shifted the negative identities foisted on them as a result of their participation in the war.
- Full Text:
- Date Issued: 2012
Catalytic activities of metallophthalocyanines towards detection and transformation of pollutants
- Authors: Agboola, Bolade Oyeyinka
- Date: 2007
- Subjects: Phthalocyanines Electrochemistry Pollutants -- Biodegradation Pollutants -- Measurement
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4427 , http://hdl.handle.net/10962/d1006922
- Description: Syntheses, spectral, electrochemical and spectroelectrochemical studies of new thiol-derivatised MPc complexes were satisfactorily carried out. For the first time, spectroelectrochemistry gave evidence for the formation of Ni²⁺/Ni⁺ process in a NiPc complex. Significant insights as to the nature of Fe⁺Pc and Ni⁺Pc spectra were obtained. Transformations of chlorophenols using chemical and photochemical methods are presented. For cobalt tetrasulphophthalocyanine catalysed oxidation of chlorophenols using hydrogen peroxide as the oxidant, types of oxidation products formed depended on the solvent conditions. Photolysis of aqueous solutions of chlorophenols in the presence of immobilised non-transition metal phthalocyanine photosensitisers onto Amerlite® was carried out. For the first time, MPcS[subscript mix] complexes were immobilised on Amberlite® for use in heterogeneous photocatalysis. Photolysis of the chlorophenols resulted mainly in the formation of chlorobenzoquinone derivatives. The generation of singlet oxygen (¹O₂) by these immobilised MPc photosensitisers was found to play a major role in their photoactivities. Modifications of gold electrodes with the newly synthesised thiol-derivatised MPc complexes via electropolymerisation and SAM techniques are presented. Cyclic voltammetry, impedance spectroscopy (NiPcs only) and spectroelectrochemical techniques (NiPcs only) confirmed that the complexes formed films on gold electrodes. Stable and well packed SAM films as evidenced by the voltammetric characterisation were obtained. For the first time, optimisation of the time for SAM formation based on CV technique was studied. First example of a formation of MnPc-SAM was achieved. Catalytic activities of the NiPc towards chlorophenol depended on the nature of the NiPc in the polymer films and also anti-fouling ability of the films depended on polymer film thickness. The FeTBMPc polymer modified gold electrode showed the best catalytic activity in terms of peak potential, E[subscript p] when compared to reported work in literature for nitrate electrooxidation. Cyclic voltammetry and spectroscopy studies showed that the CoPcs, FePcs and NiPcs catalysed nitrite oxidation involve 2 electrons in total while that of McPcs involve 1 electron. Better catalytic performance towards sulphite electrooxidation were obtained for the CoPcs, FePcs and MnPcs which have metal based redox processes within the range of the sulphite electrooxidation peak while the NiPcs which did not show metal based oxidation reaction performed less.
- Full Text:
- Date Issued: 2007
- Authors: Agboola, Bolade Oyeyinka
- Date: 2007
- Subjects: Phthalocyanines Electrochemistry Pollutants -- Biodegradation Pollutants -- Measurement
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4427 , http://hdl.handle.net/10962/d1006922
- Description: Syntheses, spectral, electrochemical and spectroelectrochemical studies of new thiol-derivatised MPc complexes were satisfactorily carried out. For the first time, spectroelectrochemistry gave evidence for the formation of Ni²⁺/Ni⁺ process in a NiPc complex. Significant insights as to the nature of Fe⁺Pc and Ni⁺Pc spectra were obtained. Transformations of chlorophenols using chemical and photochemical methods are presented. For cobalt tetrasulphophthalocyanine catalysed oxidation of chlorophenols using hydrogen peroxide as the oxidant, types of oxidation products formed depended on the solvent conditions. Photolysis of aqueous solutions of chlorophenols in the presence of immobilised non-transition metal phthalocyanine photosensitisers onto Amerlite® was carried out. For the first time, MPcS[subscript mix] complexes were immobilised on Amberlite® for use in heterogeneous photocatalysis. Photolysis of the chlorophenols resulted mainly in the formation of chlorobenzoquinone derivatives. The generation of singlet oxygen (¹O₂) by these immobilised MPc photosensitisers was found to play a major role in their photoactivities. Modifications of gold electrodes with the newly synthesised thiol-derivatised MPc complexes via electropolymerisation and SAM techniques are presented. Cyclic voltammetry, impedance spectroscopy (NiPcs only) and spectroelectrochemical techniques (NiPcs only) confirmed that the complexes formed films on gold electrodes. Stable and well packed SAM films as evidenced by the voltammetric characterisation were obtained. For the first time, optimisation of the time for SAM formation based on CV technique was studied. First example of a formation of MnPc-SAM was achieved. Catalytic activities of the NiPc towards chlorophenol depended on the nature of the NiPc in the polymer films and also anti-fouling ability of the films depended on polymer film thickness. The FeTBMPc polymer modified gold electrode showed the best catalytic activity in terms of peak potential, E[subscript p] when compared to reported work in literature for nitrate electrooxidation. Cyclic voltammetry and spectroscopy studies showed that the CoPcs, FePcs and NiPcs catalysed nitrite oxidation involve 2 electrons in total while that of McPcs involve 1 electron. Better catalytic performance towards sulphite electrooxidation were obtained for the CoPcs, FePcs and MnPcs which have metal based redox processes within the range of the sulphite electrooxidation peak while the NiPcs which did not show metal based oxidation reaction performed less.
- Full Text:
- Date Issued: 2007
The psycho-social functioning and experiences of children in child-headed households in Gauteng Province, South Africa
- Authors: Agere, Leonard Munyaradzi
- Date: 2018
- Subjects: Adult children -- South Africa -- Conduct of life Youth-headed households -- South Africa Child support -- South Africa
- Language: English
- Type: Thesis , Doctoral , Social Work
- Identifier: http://hdl.handle.net/10353/10646 , vital:35651
- Description: The study was aimed at investigating the psycho-social needs and lived experiences of child headed households in the Gauteng Province of South Africa. A mixed methods approach was used to collect and analyse the data. The qualitative approach was the dominant one, while a quantitative approach was used to corroborate the qualitative findings. The quantitative data was collected through a survey. Three hundred questionnaires were distributed among children in child headed households. The child headed households were selected through simple random sampling from the databases of the NGOs and community based organisations that had agreed to participate in the study. The quantitative component of the study produced results that supported the qualitative findings. The qualitative data was collected through in-depth interviews and focus group discussions, which were conducted with purposively selected social service practitioners and community structures who were involved in work with child headed households. The resilience approach, which posits that humans are born with inherent reserves to face adversity, and the ecological systems theory, which postulates the framework in which an individual can be understood in his constant interactions and relationships within community and wider society, inform this study. The findings of the study indicate that there were various psycho social needs and challenges that child headed households faced. As Maslow postulated in his hierarchy of needs theory, inferences were made to the diverse needs of the child headed households. Physiological needs like food, clothing and finance were found to be more presenting and eminent needs for the child headed households. The study findings highlighted safety needs in the form of need for formal housing as the majority lived in informal settlements where they were exposed to much vulnerability like violence, sexual exploitation and other social misdemeanours. Other needs were esteem and familial needs, which provided a platform to foster senses of identity and belonging. However, there were other child headed households who were fortunate to have extended family members and community based organisations that assisted by providing these needs and these gestures were appreciated by the households as they ameliorated dire situations and cushioned them from absolute poverty. The findings further revealed that the psycho social challenges and needs did not only present when the household became child headed household but when their parent/s was still with them and were only exacerbated in their absence. The effects of living with parental illness, sadness and anxiety due to dramatic changes in dynamics, pain and trauma witnessing a parent dying were among the psychosocial challenges faced when the parent was still present with the children. After their departure or absence the challenges shifted and the debilitating effects of grief and loss, emotional trauma, living without adult caregiver and stigma and discrimination, were among the cocktail of challenges that the child headed households faced. However, others had support from extended family members and community structures that supported them with palliative care for the terminally ill and this afforded them the much needed respite as they focused on their studies and enjoyed their rights to be children. The study reveals that children have several coping mechanisms that exude their resilience and this includes support from social workers in promoting sustainable development goals (SDG’s) including no poverty, good health and well-being and quality education (goals 1, 3 and 4). The study highlighted that others had to supplement education with paid work (informal) whilst some ended up disengaging from their education to pursue paid employment to eke a living and support their siblings. The community and NGO’s were seen as vital components of the ecosystem that promoted the resilience of the child headed households in coping with their day to day challenges and needs. On the basis of the findings, it is recommended that the South African government should, among other things, provide a properly resourced, co-ordinated and well managed child protection system to facilitate constituency work that responds to the real needs of child headed households and SMART planning by social workers, with systemic teaming around CHH with the DSD as lead agency. The study also recommends a psychosocial approach to CHH care in the form of a model that rallies for robust assessments that social service practitioners and every structure that has the “duty to care” for CHH, can embed in their practice for improved outcomes.
- Full Text:
- Date Issued: 2018
- Authors: Agere, Leonard Munyaradzi
- Date: 2018
- Subjects: Adult children -- South Africa -- Conduct of life Youth-headed households -- South Africa Child support -- South Africa
- Language: English
- Type: Thesis , Doctoral , Social Work
- Identifier: http://hdl.handle.net/10353/10646 , vital:35651
- Description: The study was aimed at investigating the psycho-social needs and lived experiences of child headed households in the Gauteng Province of South Africa. A mixed methods approach was used to collect and analyse the data. The qualitative approach was the dominant one, while a quantitative approach was used to corroborate the qualitative findings. The quantitative data was collected through a survey. Three hundred questionnaires were distributed among children in child headed households. The child headed households were selected through simple random sampling from the databases of the NGOs and community based organisations that had agreed to participate in the study. The quantitative component of the study produced results that supported the qualitative findings. The qualitative data was collected through in-depth interviews and focus group discussions, which were conducted with purposively selected social service practitioners and community structures who were involved in work with child headed households. The resilience approach, which posits that humans are born with inherent reserves to face adversity, and the ecological systems theory, which postulates the framework in which an individual can be understood in his constant interactions and relationships within community and wider society, inform this study. The findings of the study indicate that there were various psycho social needs and challenges that child headed households faced. As Maslow postulated in his hierarchy of needs theory, inferences were made to the diverse needs of the child headed households. Physiological needs like food, clothing and finance were found to be more presenting and eminent needs for the child headed households. The study findings highlighted safety needs in the form of need for formal housing as the majority lived in informal settlements where they were exposed to much vulnerability like violence, sexual exploitation and other social misdemeanours. Other needs were esteem and familial needs, which provided a platform to foster senses of identity and belonging. However, there were other child headed households who were fortunate to have extended family members and community based organisations that assisted by providing these needs and these gestures were appreciated by the households as they ameliorated dire situations and cushioned them from absolute poverty. The findings further revealed that the psycho social challenges and needs did not only present when the household became child headed household but when their parent/s was still with them and were only exacerbated in their absence. The effects of living with parental illness, sadness and anxiety due to dramatic changes in dynamics, pain and trauma witnessing a parent dying were among the psychosocial challenges faced when the parent was still present with the children. After their departure or absence the challenges shifted and the debilitating effects of grief and loss, emotional trauma, living without adult caregiver and stigma and discrimination, were among the cocktail of challenges that the child headed households faced. However, others had support from extended family members and community structures that supported them with palliative care for the terminally ill and this afforded them the much needed respite as they focused on their studies and enjoyed their rights to be children. The study reveals that children have several coping mechanisms that exude their resilience and this includes support from social workers in promoting sustainable development goals (SDG’s) including no poverty, good health and well-being and quality education (goals 1, 3 and 4). The study highlighted that others had to supplement education with paid work (informal) whilst some ended up disengaging from their education to pursue paid employment to eke a living and support their siblings. The community and NGO’s were seen as vital components of the ecosystem that promoted the resilience of the child headed households in coping with their day to day challenges and needs. On the basis of the findings, it is recommended that the South African government should, among other things, provide a properly resourced, co-ordinated and well managed child protection system to facilitate constituency work that responds to the real needs of child headed households and SMART planning by social workers, with systemic teaming around CHH with the DSD as lead agency. The study also recommends a psychosocial approach to CHH care in the form of a model that rallies for robust assessments that social service practitioners and every structure that has the “duty to care” for CHH, can embed in their practice for improved outcomes.
- Full Text:
- Date Issued: 2018
Balanced scorecard components as predictors of service performance management in first bank Nigeria plc 2009 – 2014
- Authors: Agomuonso, Clara Udochi
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11721 , http://hdl.handle.net/10353/d1017866
- Description: Many institutions and organizations are set up to with a right motive but fail to actualize their vision. This cuts across both public and private institutions across the globe. A financial institution is selected for this research because of its sensitivity; hence getting it right with a delicate institution like a financial organization will assist usage of this monitoring system by other institutions. Modern banking in Nigeria started in 1892 with the free banking era which ended when the Banking Ordinance of 1952 was promulgated. First Bank was the pioneer bank that was established in Nigeria in 1894 as the Bank of British West Africa. The establishment of the First Bank of Nigeria predates the birth of the Nigerian nation as a sovereign entity. The bank which was registered as the bank of British West Africa in 1894 has therefore evolved along the path of political, social and economic changes and developments of Nigeria from the colonial period to independence and the experience of post-independence. It thus shared, in the process of its growth, the tidal experiences of the nation which, in retrospect, were sources of strength (Ndekwu, 1994).
- Full Text:
- Date Issued: 2014
- Authors: Agomuonso, Clara Udochi
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (in Public Administration)
- Identifier: vital:11721 , http://hdl.handle.net/10353/d1017866
- Description: Many institutions and organizations are set up to with a right motive but fail to actualize their vision. This cuts across both public and private institutions across the globe. A financial institution is selected for this research because of its sensitivity; hence getting it right with a delicate institution like a financial organization will assist usage of this monitoring system by other institutions. Modern banking in Nigeria started in 1892 with the free banking era which ended when the Banking Ordinance of 1952 was promulgated. First Bank was the pioneer bank that was established in Nigeria in 1894 as the Bank of British West Africa. The establishment of the First Bank of Nigeria predates the birth of the Nigerian nation as a sovereign entity. The bank which was registered as the bank of British West Africa in 1894 has therefore evolved along the path of political, social and economic changes and developments of Nigeria from the colonial period to independence and the experience of post-independence. It thus shared, in the process of its growth, the tidal experiences of the nation which, in retrospect, were sources of strength (Ndekwu, 1994).
- Full Text:
- Date Issued: 2014
Exploring learners’ proficiency in stoichiometry and attitudes towards science through Process Oriented Guided Inquiry Learning (POGIL) intervention
- Authors: Agunbiade, Arinola Esther
- Date: 2021-04
- Subjects: Stoichiometry -- Study and teaching (Secondary) -- Nigeria , Chemistry -- Study and teaching (Secondary) -- Nigeria , Process-oriented guided inquiry learning , Student-centered learning -- Nigeria , Science students -- Attitudes
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/174402 , vital:42474
- Description: Stoichiometry is one of the difficult topics in the senior secondary school chemistry curriculum. It is usually taught through the traditional lecture method of presentation that is non-engaging for learners. Consequently, there is poor understanding, achievement, and negative perceptions of stoichiometry and chemistry in general. The goal of this study was to explore learners’ evolving proficiency in stoichiometry and attitudes towards science as a result of their participation in Process Oriented Guided Inquiry Learning (POGIL) activities. That is, POGIL which incorporates guided-inquiry and collaborative learning was introduced as an intervention strategy in learning stoichiometry. This was assessed by examining learners’ experiences with learning stoichiometry before and after the POGIL intervention. The study further investigated possible contributing factors to learners’ evolving proficiency in stoichiometry and attitudes towards science. This study employed the socio-cultural learning theory as proposed by Vygotsky (1978). The role of socio-cultural features such as ‘social interaction’, ‘cultural tools’, ‘self-regulation’ and ‘zone of proximal development’ (ZPD) were explored with regards to learners’ stoichiometry proficiency and attitudes towards science progression as they participated in POGIL activities. The work of Kilpatrick, Swafford and Findell (2001) on proficiency and Fraser (1981) on attitudes towards science were used as analytical lenses to understand learners’ proficiency in stoichiometry and attitudes towards science, respectively. This study was underpinned by the pragmatic research paradigm. Thus, a Quant + Qual concurrent mixed-methods approach which involves generating, analysing, and integrating both qualitative and quantitative data to provide answers to research questions was adopted. It was an intervention study carried out in two senior secondary schools in the Ilorin metropolis of Kwara State, Nigeria. A sample of 53 senior secondary school year two learners participated. Questionnaires and journal entries were completed by the 53 learners, while seven learners were interviewed. Data were collected using both qualitative and quantitative data generating tools including pre-and post-tests. The stoichiometry learning questionnaire (SLQ), test of science related attitude (TOSRA) questionnaire, and stoichiometry achievement tool (SAT) were used to generate quantitative data while the SLQ, semi-structured interviews, and journal entries were the qualitative data tools. Data were generated in three phases. Phase one was baseline data through SLQ, TOSRA and SAT pre-tests. The second phase was the intervention phase where the POGIL approach was implemented in the classrooms and learners were engaged in journal entries. Post-intervention was the last phase where TOSRA and SAT post-tests were administered and semi-structured interviews were conducted with participants. Thus, data were analysed quantitatively and qualitatively. Before the POGIL intervention, the findings of this study revealed that most of the learners perceived stoichiometry as difficult because of the instructional characteristics, the nature of stoichiometry concepts, and learners’ attributes. After the POGIL intervention, however, learners showed increased proficiency in stoichiometry and attitudes towards science. Findings also indicate that learners’ proficiency in stoichiometry and attitude towards science were associated with the facilitators or learning environment features, the nature of instructional characteristics, learners’ perceptions of stoichiometry or science, and the extent to which learners could comprehend or master science concepts. Notably, these features are intertwined and cohere with the socio-cultural theory and POGIL principles. This study offered insights into how proficiency in stoichiometry and attitudes towards science may develop among senior secondary school learners in Nigeria. The findings point to POGIL as an example of an instructional approach that provides enabling characteristics and useful information for planning instructional activities for the development and nurturing of proficiency and attitudes towards science. The results suggest that the POGIL strategy could alleviate some of the factors perceived as contributors to difficulty in learning stoichiometry. As such, the study makes contributions to the field of science education in Nigeria particularly regarding how both the tenets of the socio-cultural framework (social interaction, cultural tools, self-regulation, and ZPD) and POGIL (guided-inquiry and collaborative learning) could be aligned to facilitate the development of proficiency and attitudes towards science. The study, therefore, recommends that POGIL should be used as an inquiry-based approach in science classrooms to promote the development of learners’ proficiency and attitudes towards science. The study could also be utilised as a resource to guide or set a base for further investigation into the implementation of POGIL in other areas of chemistry or science as well as creating professional development spaces that promote community of practice among science teachers as observed in this study.
- Full Text:
- Date Issued: 2021-04
- Authors: Agunbiade, Arinola Esther
- Date: 2021-04
- Subjects: Stoichiometry -- Study and teaching (Secondary) -- Nigeria , Chemistry -- Study and teaching (Secondary) -- Nigeria , Process-oriented guided inquiry learning , Student-centered learning -- Nigeria , Science students -- Attitudes
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/174402 , vital:42474
- Description: Stoichiometry is one of the difficult topics in the senior secondary school chemistry curriculum. It is usually taught through the traditional lecture method of presentation that is non-engaging for learners. Consequently, there is poor understanding, achievement, and negative perceptions of stoichiometry and chemistry in general. The goal of this study was to explore learners’ evolving proficiency in stoichiometry and attitudes towards science as a result of their participation in Process Oriented Guided Inquiry Learning (POGIL) activities. That is, POGIL which incorporates guided-inquiry and collaborative learning was introduced as an intervention strategy in learning stoichiometry. This was assessed by examining learners’ experiences with learning stoichiometry before and after the POGIL intervention. The study further investigated possible contributing factors to learners’ evolving proficiency in stoichiometry and attitudes towards science. This study employed the socio-cultural learning theory as proposed by Vygotsky (1978). The role of socio-cultural features such as ‘social interaction’, ‘cultural tools’, ‘self-regulation’ and ‘zone of proximal development’ (ZPD) were explored with regards to learners’ stoichiometry proficiency and attitudes towards science progression as they participated in POGIL activities. The work of Kilpatrick, Swafford and Findell (2001) on proficiency and Fraser (1981) on attitudes towards science were used as analytical lenses to understand learners’ proficiency in stoichiometry and attitudes towards science, respectively. This study was underpinned by the pragmatic research paradigm. Thus, a Quant + Qual concurrent mixed-methods approach which involves generating, analysing, and integrating both qualitative and quantitative data to provide answers to research questions was adopted. It was an intervention study carried out in two senior secondary schools in the Ilorin metropolis of Kwara State, Nigeria. A sample of 53 senior secondary school year two learners participated. Questionnaires and journal entries were completed by the 53 learners, while seven learners were interviewed. Data were collected using both qualitative and quantitative data generating tools including pre-and post-tests. The stoichiometry learning questionnaire (SLQ), test of science related attitude (TOSRA) questionnaire, and stoichiometry achievement tool (SAT) were used to generate quantitative data while the SLQ, semi-structured interviews, and journal entries were the qualitative data tools. Data were generated in three phases. Phase one was baseline data through SLQ, TOSRA and SAT pre-tests. The second phase was the intervention phase where the POGIL approach was implemented in the classrooms and learners were engaged in journal entries. Post-intervention was the last phase where TOSRA and SAT post-tests were administered and semi-structured interviews were conducted with participants. Thus, data were analysed quantitatively and qualitatively. Before the POGIL intervention, the findings of this study revealed that most of the learners perceived stoichiometry as difficult because of the instructional characteristics, the nature of stoichiometry concepts, and learners’ attributes. After the POGIL intervention, however, learners showed increased proficiency in stoichiometry and attitudes towards science. Findings also indicate that learners’ proficiency in stoichiometry and attitude towards science were associated with the facilitators or learning environment features, the nature of instructional characteristics, learners’ perceptions of stoichiometry or science, and the extent to which learners could comprehend or master science concepts. Notably, these features are intertwined and cohere with the socio-cultural theory and POGIL principles. This study offered insights into how proficiency in stoichiometry and attitudes towards science may develop among senior secondary school learners in Nigeria. The findings point to POGIL as an example of an instructional approach that provides enabling characteristics and useful information for planning instructional activities for the development and nurturing of proficiency and attitudes towards science. The results suggest that the POGIL strategy could alleviate some of the factors perceived as contributors to difficulty in learning stoichiometry. As such, the study makes contributions to the field of science education in Nigeria particularly regarding how both the tenets of the socio-cultural framework (social interaction, cultural tools, self-regulation, and ZPD) and POGIL (guided-inquiry and collaborative learning) could be aligned to facilitate the development of proficiency and attitudes towards science. The study, therefore, recommends that POGIL should be used as an inquiry-based approach in science classrooms to promote the development of learners’ proficiency and attitudes towards science. The study could also be utilised as a resource to guide or set a base for further investigation into the implementation of POGIL in other areas of chemistry or science as well as creating professional development spaces that promote community of practice among science teachers as observed in this study.
- Full Text:
- Date Issued: 2021-04
A best-practice guideline for facilitating adherence to anti-retroviral therapy for persons attending public hospitals in Ghana
- Authors: Agyeman-Yeboah, Joana
- Date: 2017
- Subjects: HIV infections -- Treatment -- Ghana , Health services administration -- Ghana Public health -- Ghana Hospital care -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13603 , vital:27256
- Description: The retention of persons on an HIV programme has been a global challenge. The success of any strategy to optimize adherence to anti-retroviral therapy (ART) depends on the intensive and effective adherence counselling and strategies. It is important to research whether persons receiving anti-retroviral therapy in public hospitals in Ghana are receiving the needed service that would optimize their adherence to the anti-retroviral therapy. Therefore, this study explored and described the experiences of healthcare professionals providing care, support and guidance to persons on ART at public hospitals in Ghana, as well as the best-practice guideline that could contribute to facilitating the ART adherence of patients. This study also explored and described the experiences of persons living with Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) on ART, regarding their adherence to the therapy. The study was organized into three phases. In Phase One: a qualitative, exploratory, descriptive and contextual design was employed. The research population included healthcare professionals, providing services at the HIV clinic at the public hospitals in Ghana, namely the Korle-Bu Teaching Hospital; the 37 Military Hospital and the Ridge Hospital. The healthcare professionals comprised of doctors, nurses, pharmacists and trained counsellors employed in any of the three public hospitals. Persons receiving ART at any of the three public hospitals were also part of the research population. Semi-structured interviews were conducted with healthcare professionals and persons receiving ART. Data were collected from healthcare professionals in relation to their experiences regarding the provision of ART services, their understanding of evidence-based practice and best-practice guidelines, as well as data on the experiences of persons receiving ART in relation to their adherence to the therapy. The data were analysed using Creswell’s six steps of data analysis; and the coding of the data was done according to Tesch’s eight steps of coding. Trustworthiness was ensured by using Lincoln and Guba’s framework which comprised credibility, transferability, dependability, confirmability and authenticity. Ethical principles such as beneficence and non-maleficence, respect for human dignity, justice, veracity, privacy and confidentiality were considered in the study. In phase two, the literature was searched by using an integrative literature review approach and critically appraising the methodological quality of the guidelines in order to identify the best available evidence related to adherence to ART. In Phase Three, a best-practice guideline for facilitating adherence to ART was developed for public hospitals in Ghana based on the findings of the empirical research of Phase One and the integrative literature review in Phase Two. The guideline was submitted to an expert panel for review; and it was modified, according to the recommendations of the panel.
- Full Text:
- Date Issued: 2017
- Authors: Agyeman-Yeboah, Joana
- Date: 2017
- Subjects: HIV infections -- Treatment -- Ghana , Health services administration -- Ghana Public health -- Ghana Hospital care -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13603 , vital:27256
- Description: The retention of persons on an HIV programme has been a global challenge. The success of any strategy to optimize adherence to anti-retroviral therapy (ART) depends on the intensive and effective adherence counselling and strategies. It is important to research whether persons receiving anti-retroviral therapy in public hospitals in Ghana are receiving the needed service that would optimize their adherence to the anti-retroviral therapy. Therefore, this study explored and described the experiences of healthcare professionals providing care, support and guidance to persons on ART at public hospitals in Ghana, as well as the best-practice guideline that could contribute to facilitating the ART adherence of patients. This study also explored and described the experiences of persons living with Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) on ART, regarding their adherence to the therapy. The study was organized into three phases. In Phase One: a qualitative, exploratory, descriptive and contextual design was employed. The research population included healthcare professionals, providing services at the HIV clinic at the public hospitals in Ghana, namely the Korle-Bu Teaching Hospital; the 37 Military Hospital and the Ridge Hospital. The healthcare professionals comprised of doctors, nurses, pharmacists and trained counsellors employed in any of the three public hospitals. Persons receiving ART at any of the three public hospitals were also part of the research population. Semi-structured interviews were conducted with healthcare professionals and persons receiving ART. Data were collected from healthcare professionals in relation to their experiences regarding the provision of ART services, their understanding of evidence-based practice and best-practice guidelines, as well as data on the experiences of persons receiving ART in relation to their adherence to the therapy. The data were analysed using Creswell’s six steps of data analysis; and the coding of the data was done according to Tesch’s eight steps of coding. Trustworthiness was ensured by using Lincoln and Guba’s framework which comprised credibility, transferability, dependability, confirmability and authenticity. Ethical principles such as beneficence and non-maleficence, respect for human dignity, justice, veracity, privacy and confidentiality were considered in the study. In phase two, the literature was searched by using an integrative literature review approach and critically appraising the methodological quality of the guidelines in order to identify the best available evidence related to adherence to ART. In Phase Three, a best-practice guideline for facilitating adherence to ART was developed for public hospitals in Ghana based on the findings of the empirical research of Phase One and the integrative literature review in Phase Two. The guideline was submitted to an expert panel for review; and it was modified, according to the recommendations of the panel.
- Full Text:
- Date Issued: 2017
The impact of child sexual abuse (CSA) on the school life experiences and academic performance of adult CSA survivors
- Ah Hing, Antoinette Danielle
- Authors: Ah Hing, Antoinette Danielle
- Date: 2010
- Subjects: Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9478 , http://hdl.handle.net/10948/1259 , Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Description: Child Sexual Abuse (CSA) is a societal problem whose origins date back to the times of the ancient Greeks and Romans. It is found in all levels of society, from the wealthiest to the poorest; and the short-term and long-term impacts it has on the lives of the victims, can be devastating. There are many reasons for the occurrence of child sexual abuse, but in all cases, the ultimate accountability rests on the shoulders of the sexual offender. The nature of child sexual victimisation varies from verbal suggestions to violent physical force. Irrespective of which type the child is being subjected to, as the weaker partner in the pedagogical relationship with the adult, s/he is never able to defend herself/himself. The global phenomenon, and the increase in CSA, has given rise to the research question, namely: How does child sexual abuse impact on the school life experiences and academic performance of learners at school? The purpose of this research study was to provide insight into the following issues: • The nature and identification of the symptoms of child sexual abuse; • The manner in which sexually abused children manifest their experiences of sexual abuse at school; • How sexually abused children cope with their learning tasks; and • Recommendations for educators. The literature relating to CSA was reviewed, with the aim of establishing a solid theoretical foundation for the study. CSA has been looked at holistically, encompassing the accepted definitions, the related concepts, the nature of sexual abuse, the prevalence and incidence of CSA, the possible causes, the short-term and long-term impacts, and the suggestions by adult survivors for use by educators in their efforts to help abused learners. 11 In an attempt to provide acceptable answers to the research problem, a mixed- method research design was implemented. The research study was conducted in two phases: Stage 1 consisted of an exploration of the research problem by means of the following question put to the participants: In your experience as an adult survivor of child sexual abuse how did the abuse impact on your school life experiences, including your academic performance? A total of nineteen participants from the Eastern Cape Province shared their experiences, by means of writing their life story as a narrative. Purposive and availability sampling of adult survivors was undertaken. In order to ensure the trustworthiness and authenticity of the research methodology, Guba’s model of data verification was used. Accepted ethical measures were taken into consideration and adhered to during the research. The analysed data were taken directly from the narratives that the individual participants saved onto flashdrives. Consensus by the researcher and coder was reached regarding the identification of themes, categories and subcategories. The following four significant themes emerged, based on the results of the data analysis: Theme One: Health, sexuality and the sexual experiences of sexual abused children and adolescents. Theme Two: The social development of sexually abused children and adolescents. Theme Three: School-related experiences and academic performance of sexually abused children and adolescents. Theme Four: Advice and suggestions from adult survivors for young victims of CSA. 12 Stage 2 offered recommendations to the teachers of learners who are, or have been sexually abused, derived from the findings of Phase 1. The conclusion was reached that CSA does have an impact on the academic performance of learners. Therefore, teachers are in need of a greater understanding and awareness of CSA, in order to help these learners.
- Full Text:
- Date Issued: 2010
- Authors: Ah Hing, Antoinette Danielle
- Date: 2010
- Subjects: Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9478 , http://hdl.handle.net/10948/1259 , Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Description: Child Sexual Abuse (CSA) is a societal problem whose origins date back to the times of the ancient Greeks and Romans. It is found in all levels of society, from the wealthiest to the poorest; and the short-term and long-term impacts it has on the lives of the victims, can be devastating. There are many reasons for the occurrence of child sexual abuse, but in all cases, the ultimate accountability rests on the shoulders of the sexual offender. The nature of child sexual victimisation varies from verbal suggestions to violent physical force. Irrespective of which type the child is being subjected to, as the weaker partner in the pedagogical relationship with the adult, s/he is never able to defend herself/himself. The global phenomenon, and the increase in CSA, has given rise to the research question, namely: How does child sexual abuse impact on the school life experiences and academic performance of learners at school? The purpose of this research study was to provide insight into the following issues: • The nature and identification of the symptoms of child sexual abuse; • The manner in which sexually abused children manifest their experiences of sexual abuse at school; • How sexually abused children cope with their learning tasks; and • Recommendations for educators. The literature relating to CSA was reviewed, with the aim of establishing a solid theoretical foundation for the study. CSA has been looked at holistically, encompassing the accepted definitions, the related concepts, the nature of sexual abuse, the prevalence and incidence of CSA, the possible causes, the short-term and long-term impacts, and the suggestions by adult survivors for use by educators in their efforts to help abused learners. 11 In an attempt to provide acceptable answers to the research problem, a mixed- method research design was implemented. The research study was conducted in two phases: Stage 1 consisted of an exploration of the research problem by means of the following question put to the participants: In your experience as an adult survivor of child sexual abuse how did the abuse impact on your school life experiences, including your academic performance? A total of nineteen participants from the Eastern Cape Province shared their experiences, by means of writing their life story as a narrative. Purposive and availability sampling of adult survivors was undertaken. In order to ensure the trustworthiness and authenticity of the research methodology, Guba’s model of data verification was used. Accepted ethical measures were taken into consideration and adhered to during the research. The analysed data were taken directly from the narratives that the individual participants saved onto flashdrives. Consensus by the researcher and coder was reached regarding the identification of themes, categories and subcategories. The following four significant themes emerged, based on the results of the data analysis: Theme One: Health, sexuality and the sexual experiences of sexual abused children and adolescents. Theme Two: The social development of sexually abused children and adolescents. Theme Three: School-related experiences and academic performance of sexually abused children and adolescents. Theme Four: Advice and suggestions from adult survivors for young victims of CSA. 12 Stage 2 offered recommendations to the teachers of learners who are, or have been sexually abused, derived from the findings of Phase 1. The conclusion was reached that CSA does have an impact on the academic performance of learners. Therefore, teachers are in need of a greater understanding and awareness of CSA, in order to help these learners.
- Full Text:
- Date Issued: 2010
Development of InSb/GaSb quantum dots by MOVPE
- Authors: Ahia, Chinedu Christian
- Date: 2018
- Subjects: Semiconductors , Quantum electronics Organometallic compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23382 , vital:30537
- Description: There has been an increasing interest in the modification of semiconductor band structures through the reduction of their dimensions, which simultaneously increases the band gap energy of the material and gives rise to flexibility in device properties. Advances in III-V antimony (Sb) based semiconductor fabrication have triggered the quest for extension of the emission/absorption wavelength range of this family of compounds for optoelectronic devices operating in the mid-infrared region of the electromagnetic spectrum. An interesting material system for mid-infrared (MIR) applications is indium antimonide (InSb) quantum dots (QDs) within a gallium antimonide (GaSb) matrix. However, its band alignment and emission wavelength has been the subject of some interest and controversy over the years. This study focuses on the development of InSb/GaSb QDs by metal organic vapour phase epitaxy (MOVPE). The samples were grown on different substrates using various growth parameters in order to vary the size, density and aspect ratio of the dots. Interfacial growth interruptions while flowing various source precursors through the reactor were investigated in order to influence the chemical termination of the surface, and hence the resulting strain in the structures. The samples were characterized using photoluminescence spectroscopy, scanning probe microscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy. Likewise, the band alignment, energy levels, and carrier wave functions of the samples in this work were modelled theoretically using the nextnanomat software (version 3.1.0.0). A comparison of growth on two different GaSb substrates [(100) 2° off towards <111>B ± 0.1ᵒ and (111) ± 0.1ᵒ] using similar growth conditions yielded a higher dot density on the (100) substrate compared to the (111) substrate. This was attributed to the presence of terraces/atomic steps induced by the misorientation on the (100) substrate, which invariably gives rise to increased adsorption and an enhanced sticking coefficient of adatoms. Studies on the influence of a buffer layer on the morphology of uncapped dots showed that the shape and size of the dots are sensitive to the thickness of the buffer layer. In some case a corrugated buffer surface resulted, which introduced order in the arrangement of the dots, which formed preferentially inside the troughs. An increase in the V/III ratio from 1.0 to 3.0 was found to reduce the areal density of the QDs, while an analysis of the diameter histograms showed a narrowing of the size distribution with an increase in V/III ratio. The larger size distribution at low V/III was ascribed to the increase in indium species and the increased indium adatom migration length. This leads to increased dot density and nucleation sites, and thus triggers an increase in the conversion of tiny QDs into thermodynamically more suitable larger dots via coalescence. However, as the V/III ratio increased, the number of indium adatoms available for growth on the surface reduced, which automatically led to a decrease in the migration length of indium species which is unfavourable for the production of nucleation sites and to a decrease in dot density. Low growth rates were found to be beneficial for the growth of a high density (~5×1010cm-2) of QDs. Photoluminescence (PL) analysis of the capped samples at low temperature (~10 K), using an excitation power of 2 mW, showed a PL peak at ∼732 meV. Upon an increase in laser power to 120 mW, a blue shift of ∼ 8 meV was noticed. This emission typically persisted up to 60–70 K. An increase in the number of InSb QD-layers, was observed to cause an increase in the luminescence spectral line width and a long-wavelength shift of the PL lines, together with an enhancement in the strength of the PL emission. However, high resolution transmission electron microscopy (HRTEM) of the capped dots revealed the formation of an InGaSb quantum well-like structure, ∼10 nm thick, which was responsible for the PL signal mentioned above. The absence of QDs in the capped sample was attributed to inter-diffusion of Ga and In during the deposition of the cap layer, giving rise to a quantum well (QW) instead of the intended QDs. The presence of threading dislocations and stacking faults were also observed in the TEM micrographs of the samples containing multilayers, which can account for the fast quenching of the PL emission with increasing temperature from these samples. Theoretical simulations of the band alignment, wave functions and energy levels were in good agreement with the data collected from the PL spectra of the samples.
- Full Text:
- Date Issued: 2018
- Authors: Ahia, Chinedu Christian
- Date: 2018
- Subjects: Semiconductors , Quantum electronics Organometallic compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23382 , vital:30537
- Description: There has been an increasing interest in the modification of semiconductor band structures through the reduction of their dimensions, which simultaneously increases the band gap energy of the material and gives rise to flexibility in device properties. Advances in III-V antimony (Sb) based semiconductor fabrication have triggered the quest for extension of the emission/absorption wavelength range of this family of compounds for optoelectronic devices operating in the mid-infrared region of the electromagnetic spectrum. An interesting material system for mid-infrared (MIR) applications is indium antimonide (InSb) quantum dots (QDs) within a gallium antimonide (GaSb) matrix. However, its band alignment and emission wavelength has been the subject of some interest and controversy over the years. This study focuses on the development of InSb/GaSb QDs by metal organic vapour phase epitaxy (MOVPE). The samples were grown on different substrates using various growth parameters in order to vary the size, density and aspect ratio of the dots. Interfacial growth interruptions while flowing various source precursors through the reactor were investigated in order to influence the chemical termination of the surface, and hence the resulting strain in the structures. The samples were characterized using photoluminescence spectroscopy, scanning probe microscopy, scanning electron microscopy, X-ray diffraction and transmission electron microscopy. Likewise, the band alignment, energy levels, and carrier wave functions of the samples in this work were modelled theoretically using the nextnanomat software (version 3.1.0.0). A comparison of growth on two different GaSb substrates [(100) 2° off towards <111>B ± 0.1ᵒ and (111) ± 0.1ᵒ] using similar growth conditions yielded a higher dot density on the (100) substrate compared to the (111) substrate. This was attributed to the presence of terraces/atomic steps induced by the misorientation on the (100) substrate, which invariably gives rise to increased adsorption and an enhanced sticking coefficient of adatoms. Studies on the influence of a buffer layer on the morphology of uncapped dots showed that the shape and size of the dots are sensitive to the thickness of the buffer layer. In some case a corrugated buffer surface resulted, which introduced order in the arrangement of the dots, which formed preferentially inside the troughs. An increase in the V/III ratio from 1.0 to 3.0 was found to reduce the areal density of the QDs, while an analysis of the diameter histograms showed a narrowing of the size distribution with an increase in V/III ratio. The larger size distribution at low V/III was ascribed to the increase in indium species and the increased indium adatom migration length. This leads to increased dot density and nucleation sites, and thus triggers an increase in the conversion of tiny QDs into thermodynamically more suitable larger dots via coalescence. However, as the V/III ratio increased, the number of indium adatoms available for growth on the surface reduced, which automatically led to a decrease in the migration length of indium species which is unfavourable for the production of nucleation sites and to a decrease in dot density. Low growth rates were found to be beneficial for the growth of a high density (~5×1010cm-2) of QDs. Photoluminescence (PL) analysis of the capped samples at low temperature (~10 K), using an excitation power of 2 mW, showed a PL peak at ∼732 meV. Upon an increase in laser power to 120 mW, a blue shift of ∼ 8 meV was noticed. This emission typically persisted up to 60–70 K. An increase in the number of InSb QD-layers, was observed to cause an increase in the luminescence spectral line width and a long-wavelength shift of the PL lines, together with an enhancement in the strength of the PL emission. However, high resolution transmission electron microscopy (HRTEM) of the capped dots revealed the formation of an InGaSb quantum well-like structure, ∼10 nm thick, which was responsible for the PL signal mentioned above. The absence of QDs in the capped sample was attributed to inter-diffusion of Ga and In during the deposition of the cap layer, giving rise to a quantum well (QW) instead of the intended QDs. The presence of threading dislocations and stacking faults were also observed in the TEM micrographs of the samples containing multilayers, which can account for the fast quenching of the PL emission with increasing temperature from these samples. Theoretical simulations of the band alignment, wave functions and energy levels were in good agreement with the data collected from the PL spectra of the samples.
- Full Text:
- Date Issued: 2018
Elucidating Tuta absoluta (Meyrick) invasion and enhancing its management in Eastern Africa : spread, socio-ecological impacts, and potential of a newly imported larval parasitoid for classical biological control Eastern in Africa
- Aigbedion-Atalor, Pascal Osabhahiemen
- Authors: Aigbedion-Atalor, Pascal Osabhahiemen
- Date: 2021
- Subjects: Tuta absoluta -- Biological control , Tomatoes -- Diseases and pests -- Africa, East , Braconidae , Gelechiidae -- Biological control -- Africa, East , Insects as biological pest control agents -- Africa, East
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/170421 , vital:41920 , 10.21504/10962/170421
- Description: Agriculture is a fundamental source of sustainable livelihoods in sub-Saharan Africa and millions of people in the region rely solely on small-scale farming for their food security. However, the impacts of invasive alien species (IAS) on crop production are serious, and there is no sign of this abating. Among the recent IAS that have invaded Africa in the last decade, the South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has been one of the most damaging. Following its first record in the Maghreb region of Africa in 2008, T. absoluta rapidly spread throughout Africa with substantial impacts on tomato production, often causing 100% yield loss. Management options adopted against T. absoluta by tomato growers in Africa have been based on the use of synthetic insecticides. While chemical insecticide applications are an important component of an integrated pest management programme, misuse and over-reliance often exacerbates the impacts of T. absolutadue to the development of resistance to commonly used active substances, increasing the fitness of the pest. This thesis sought to understand the socio-economic impacts of the spread of T. absoluta in Eastern Africa and provide effective sustainable pest management strategies to reduce its impacts below economic thresholds. Mapping surveys of Tabsoluta were conducted in 226 tomato agro-ecosystems across four eastern countries (Kenya, Sudan, Tanzania, and Uganda) Eastern Africa from 2016 to 2018 to determine the spatiotemporal distribution of the pest. The impacts of T. absoluta on the livelihoods of tomato growers were also assessed. Here, 200 tomato growers in Kenya were interviewed using a semi-structured questionnaire. Although T. absoluta, a recent invader, was distributed at high infestation levels throughout the subregion (all four countries) and was considered as the most damaging invasive alien species of agriculturally sustainable livelihoods. The arrival of T. absoluta in the subregion has resulted in livelihood losses and increased the cost of tomato production and price of the fruit, and the frequency of pesticide applications. The impact of this pest and the and the absence of effective indigenous natural enemies of the pest in Eastern Africa, was the rationale for the importation of a larval parasitoid, Dolichogenidea gelechiidivoris Marsh Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta from Peru into the quarantine facility of the International Centre of Insect Physiology and ecologyz(icipe), in Kenya. Pre-release assessments on the parasitzation potential of D. gelechiidivoris, encompassing host larval preference and the host suitability, and its reproductive strategy, for classical biological control of T. absoluta in Africa were conducted. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post-eclosion. The females of D. gelechiidivoris survived 8.51±0.65 d and produced 103±8 offspring per female at 26±4°C (range: 24 to 29°C) and 50–70% relative humidity (RH) in the presence of males and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The estimated intrinsic rate of natural increase was 0.18. These findings indicate that D. gelechiidivorisis a potential biological control agent of T. absoluta and should be considered for augmentative/inundative release in Kenya and across Africa following host specificity testing and risk assessments. The nature of the interaction between D. gelechidivoris and the predatory mirid bug Nesidiocoris tenuis(Reuter) (Hemiptera: Miridae), an important and widespread natural enemy of T. absoluta in Africa was evaluated because N. tenuis, although being a voracious predator of T. absoluta eggs, it can also prey on the early host larval instars (1st and 2nd) which are the preferred oviposition host stages of D. gelechiidivoris. Here, the impact of N. tenuis feeding on T. absoluta and the effects on D. gelechiidivoris performance was tested. Regardless of the order of introductions (i.e. the sequence of combination with D. gelechiidivoris) and densities (i.e. number of N. tenuis combined with D. gelechiidivoris), there was no intraguild predation by N. tenuis on D. gelechiidivorisas there was little host larval feeding behaviour. Also, the presence of N. tenuis did not affect the oviposition performance of D. gelechiidivoris. Further investigations revealed that the combined efficacy of N. tenuis and D. gelechiidivorison T. absoluta population was significantly higher than either natural enemy alone, thus contributes to the data supporting the release of D. gelechiidivoris in Africa. In concluding, integrating D. gelechiidivoris and N. tenuis in the management of T. absolut could potentially reduce yield losses in tomato in Eastern Africa where the socio-economic impacts of the pest are very serious.
- Full Text:
- Date Issued: 2021
- Authors: Aigbedion-Atalor, Pascal Osabhahiemen
- Date: 2021
- Subjects: Tuta absoluta -- Biological control , Tomatoes -- Diseases and pests -- Africa, East , Braconidae , Gelechiidae -- Biological control -- Africa, East , Insects as biological pest control agents -- Africa, East
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/170421 , vital:41920 , 10.21504/10962/170421
- Description: Agriculture is a fundamental source of sustainable livelihoods in sub-Saharan Africa and millions of people in the region rely solely on small-scale farming for their food security. However, the impacts of invasive alien species (IAS) on crop production are serious, and there is no sign of this abating. Among the recent IAS that have invaded Africa in the last decade, the South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has been one of the most damaging. Following its first record in the Maghreb region of Africa in 2008, T. absoluta rapidly spread throughout Africa with substantial impacts on tomato production, often causing 100% yield loss. Management options adopted against T. absoluta by tomato growers in Africa have been based on the use of synthetic insecticides. While chemical insecticide applications are an important component of an integrated pest management programme, misuse and over-reliance often exacerbates the impacts of T. absolutadue to the development of resistance to commonly used active substances, increasing the fitness of the pest. This thesis sought to understand the socio-economic impacts of the spread of T. absoluta in Eastern Africa and provide effective sustainable pest management strategies to reduce its impacts below economic thresholds. Mapping surveys of Tabsoluta were conducted in 226 tomato agro-ecosystems across four eastern countries (Kenya, Sudan, Tanzania, and Uganda) Eastern Africa from 2016 to 2018 to determine the spatiotemporal distribution of the pest. The impacts of T. absoluta on the livelihoods of tomato growers were also assessed. Here, 200 tomato growers in Kenya were interviewed using a semi-structured questionnaire. Although T. absoluta, a recent invader, was distributed at high infestation levels throughout the subregion (all four countries) and was considered as the most damaging invasive alien species of agriculturally sustainable livelihoods. The arrival of T. absoluta in the subregion has resulted in livelihood losses and increased the cost of tomato production and price of the fruit, and the frequency of pesticide applications. The impact of this pest and the and the absence of effective indigenous natural enemies of the pest in Eastern Africa, was the rationale for the importation of a larval parasitoid, Dolichogenidea gelechiidivoris Marsh Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta from Peru into the quarantine facility of the International Centre of Insect Physiology and ecologyz(icipe), in Kenya. Pre-release assessments on the parasitzation potential of D. gelechiidivoris, encompassing host larval preference and the host suitability, and its reproductive strategy, for classical biological control of T. absoluta in Africa were conducted. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post-eclosion. The females of D. gelechiidivoris survived 8.51±0.65 d and produced 103±8 offspring per female at 26±4°C (range: 24 to 29°C) and 50–70% relative humidity (RH) in the presence of males and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The estimated intrinsic rate of natural increase was 0.18. These findings indicate that D. gelechiidivorisis a potential biological control agent of T. absoluta and should be considered for augmentative/inundative release in Kenya and across Africa following host specificity testing and risk assessments. The nature of the interaction between D. gelechidivoris and the predatory mirid bug Nesidiocoris tenuis(Reuter) (Hemiptera: Miridae), an important and widespread natural enemy of T. absoluta in Africa was evaluated because N. tenuis, although being a voracious predator of T. absoluta eggs, it can also prey on the early host larval instars (1st and 2nd) which are the preferred oviposition host stages of D. gelechiidivoris. Here, the impact of N. tenuis feeding on T. absoluta and the effects on D. gelechiidivoris performance was tested. Regardless of the order of introductions (i.e. the sequence of combination with D. gelechiidivoris) and densities (i.e. number of N. tenuis combined with D. gelechiidivoris), there was no intraguild predation by N. tenuis on D. gelechiidivorisas there was little host larval feeding behaviour. Also, the presence of N. tenuis did not affect the oviposition performance of D. gelechiidivoris. Further investigations revealed that the combined efficacy of N. tenuis and D. gelechiidivorison T. absoluta population was significantly higher than either natural enemy alone, thus contributes to the data supporting the release of D. gelechiidivoris in Africa. In concluding, integrating D. gelechiidivoris and N. tenuis in the management of T. absolut could potentially reduce yield losses in tomato in Eastern Africa where the socio-economic impacts of the pest are very serious.
- Full Text:
- Date Issued: 2021
Synergistic potententials and isolation of bioactive compounds from the extracts of two helichrysum species indigenous to the Eastern Cape province
- Authors: Aiyegoro, Olayinka Ayobami
- Date: 2010
- Subjects: Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11268 , http://hdl.handle.net/10353/250 , Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Description: Helichrysum longifolium and H. pedunculatum belong to the Astereceae family and are used extensively in folkloric medicine in South Africa to manage stress-related ailments and as dressings for wounds normally encountered in circumcision rites, bruises, cuts and sores. The in vitro antibacterial time-kill studies, the synergistic potentials, the phytochemical screenings and antioxidant potentials as well as the isolation of the bioactive compounds from the extracts of these two plants were carried out in this study. The in vitro antibacterial activities and time kill regimes of crude extracts of H. pedunculatum was assessed. The extracts was active against both Gram positive and Gram negative bacteria tested at a concentration of 10 mg/ml. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.1 – 35 mg/ml. The average log reduction in viable cell count in time kill assay ranged between 0.17 Log10 to 6.37 Log10 cfu/ml after 6 h of interaction, and between 0.14 Log10 and 6.99 Log10 cfu/ml after 12 h interaction in 1 × MIC and 2 × MIC of the extract. The effect of the aqueous extract was only bacteriostatic on both reference and environmental strains and the clinical isolates were outrightly resistant to aqueous extract. This is worrisome and this could be one reason why, there is an incidence of high death rate resulting from circumcision wounds infection even after treating such wounds with H. pedunculatum leaf. In vitro antibacterial time kill studies of extracts of H. longifolium was assessed. All test bacteria were susceptible to the methanol extract, while none was susceptible to the aqueous extract. Two of the test bacteria were susceptible to the ethyl acetate extract, while ten and seven were susceptible to the acetone and chloroform extracts respectively at the test concentration of 5 mg/ml. The minimum inhibitory concentrations (MICs) ranged between 0.1 and 5.0 mg/ml, while minimum bactericidal concentrations (MBCs) ranged between 1.0 and >5 mg/ml for all the extracts. Average log reductions in viable cell counts for all the extracts ranged between 0.1 Log10 and 7.5 Log10 cfu/ml after 12 h interaction at 1 × MIC and 2 × MIC. Most of the extracts were rapidly bactericidal at 2 × MIC achieving a complete elimination of most of the test organisms within 12 h exposure time. The effect of combinations of the crude extracts of H. pedunculatum leaves and eight antibiotics was investigated by means of checkerboard and time-kill methods. In the checkerboard method, synergies of between 45.83-56.81 percent were observed and this is independent of Gram reaction, with combinations in the aqueous extract yielding largely antagonistic interactions (18.75 percent). The time kill assay also detected synergy that is independent of Gram reaction with a ≥ 3Log10 potentiation of the bactericidal activity of the test antibiotics. We conclude that the crude leaf extracts of H. pedunculatum could be potential source of broad spectrum antibiotics resistance modulating compounds. The interactions between crude extracts of H. longifolium in combination with six first-line antibiotics using both the time-kill and the checkerboard methods were carried out. The time-kill method revealed the highest bactericidal activity exemplified by a 6.7 Log10 reduction in cell density against Salmonella sp. when the extract and Penicillin G are combined at ½ × MIC. Synergistic response constituted about 65 percent, while indifference and antagonism constituted about 28.33 percent and 6.67 percent in the time kill assay, respectively. The checkerboard method also revealed that the extracts improved bactericidal effects of the antibiotics. About 61.67 percent of all the interactions were synergistic, while indifference interactions constituted about 26.67 percent and antagonistic interactions was observed in approximately 11.66 percent. The in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extracts of H. longifolium and H. pedunculatum was investigated. The scavenging activity on superoxide anions, DPPH, H2O2, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extracts. The extracts exhibited scavenging activity in all radicals tested due to the presence of relatively high total phenol and flavonoids contents in the extracts. Our findings suggest that H. longifolium and H. pedunculatum are endowed with antioxidant phytochemicals and could serve as a base for future drugs. Bioactivity-guided fractionation of the leaves of H. longifolium and H. pedunculatum yielded two known compounds. From the n-hexane fraction of H. longifolium a compound was isolated (Stigmasterol) and from the ethyl acetate fraction of H. pedunculatum another compound (β-sitosterol) was isolated. The compounds were isolated and identified using various techniques. The antimicrobial, anti-inflammatory, antioxidant, analgesic and anti-pyretic activities of these compounds have been reported in literatures. In general, the experiments and tests conducted in this study appear to have justified the folkloric medicinal uses of H. longifolium and H. pedunculatum for the treatment of stress related ailments and wound infections and make a substantial contribution to the knowledge base of the use of herbal medicine for the treatment of the microbial infections.
- Full Text:
- Date Issued: 2010
- Authors: Aiyegoro, Olayinka Ayobami
- Date: 2010
- Subjects: Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11268 , http://hdl.handle.net/10353/250 , Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Description: Helichrysum longifolium and H. pedunculatum belong to the Astereceae family and are used extensively in folkloric medicine in South Africa to manage stress-related ailments and as dressings for wounds normally encountered in circumcision rites, bruises, cuts and sores. The in vitro antibacterial time-kill studies, the synergistic potentials, the phytochemical screenings and antioxidant potentials as well as the isolation of the bioactive compounds from the extracts of these two plants were carried out in this study. The in vitro antibacterial activities and time kill regimes of crude extracts of H. pedunculatum was assessed. The extracts was active against both Gram positive and Gram negative bacteria tested at a concentration of 10 mg/ml. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.1 – 35 mg/ml. The average log reduction in viable cell count in time kill assay ranged between 0.17 Log10 to 6.37 Log10 cfu/ml after 6 h of interaction, and between 0.14 Log10 and 6.99 Log10 cfu/ml after 12 h interaction in 1 × MIC and 2 × MIC of the extract. The effect of the aqueous extract was only bacteriostatic on both reference and environmental strains and the clinical isolates were outrightly resistant to aqueous extract. This is worrisome and this could be one reason why, there is an incidence of high death rate resulting from circumcision wounds infection even after treating such wounds with H. pedunculatum leaf. In vitro antibacterial time kill studies of extracts of H. longifolium was assessed. All test bacteria were susceptible to the methanol extract, while none was susceptible to the aqueous extract. Two of the test bacteria were susceptible to the ethyl acetate extract, while ten and seven were susceptible to the acetone and chloroform extracts respectively at the test concentration of 5 mg/ml. The minimum inhibitory concentrations (MICs) ranged between 0.1 and 5.0 mg/ml, while minimum bactericidal concentrations (MBCs) ranged between 1.0 and >5 mg/ml for all the extracts. Average log reductions in viable cell counts for all the extracts ranged between 0.1 Log10 and 7.5 Log10 cfu/ml after 12 h interaction at 1 × MIC and 2 × MIC. Most of the extracts were rapidly bactericidal at 2 × MIC achieving a complete elimination of most of the test organisms within 12 h exposure time. The effect of combinations of the crude extracts of H. pedunculatum leaves and eight antibiotics was investigated by means of checkerboard and time-kill methods. In the checkerboard method, synergies of between 45.83-56.81 percent were observed and this is independent of Gram reaction, with combinations in the aqueous extract yielding largely antagonistic interactions (18.75 percent). The time kill assay also detected synergy that is independent of Gram reaction with a ≥ 3Log10 potentiation of the bactericidal activity of the test antibiotics. We conclude that the crude leaf extracts of H. pedunculatum could be potential source of broad spectrum antibiotics resistance modulating compounds. The interactions between crude extracts of H. longifolium in combination with six first-line antibiotics using both the time-kill and the checkerboard methods were carried out. The time-kill method revealed the highest bactericidal activity exemplified by a 6.7 Log10 reduction in cell density against Salmonella sp. when the extract and Penicillin G are combined at ½ × MIC. Synergistic response constituted about 65 percent, while indifference and antagonism constituted about 28.33 percent and 6.67 percent in the time kill assay, respectively. The checkerboard method also revealed that the extracts improved bactericidal effects of the antibiotics. About 61.67 percent of all the interactions were synergistic, while indifference interactions constituted about 26.67 percent and antagonistic interactions was observed in approximately 11.66 percent. The in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extracts of H. longifolium and H. pedunculatum was investigated. The scavenging activity on superoxide anions, DPPH, H2O2, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extracts. The extracts exhibited scavenging activity in all radicals tested due to the presence of relatively high total phenol and flavonoids contents in the extracts. Our findings suggest that H. longifolium and H. pedunculatum are endowed with antioxidant phytochemicals and could serve as a base for future drugs. Bioactivity-guided fractionation of the leaves of H. longifolium and H. pedunculatum yielded two known compounds. From the n-hexane fraction of H. longifolium a compound was isolated (Stigmasterol) and from the ethyl acetate fraction of H. pedunculatum another compound (β-sitosterol) was isolated. The compounds were isolated and identified using various techniques. The antimicrobial, anti-inflammatory, antioxidant, analgesic and anti-pyretic activities of these compounds have been reported in literatures. In general, the experiments and tests conducted in this study appear to have justified the folkloric medicinal uses of H. longifolium and H. pedunculatum for the treatment of stress related ailments and wound infections and make a substantial contribution to the knowledge base of the use of herbal medicine for the treatment of the microbial infections.
- Full Text:
- Date Issued: 2010
Analyses of Retail and Transport Geography of Liquefied Petroleum Products in Ibadan metropolis, Nigeria
- Authors: Ajayi, Adeyinka Peter
- Date: 2019
- Subjects: Petroleum products
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/19065 , vital:40090
- Description: This study analyzed the effects that spatial arrangement of petroleum products retail outlets and the supply chain management techniques employed for products distribution (for both intra city and intercity shipments) have on the retailing dynamism of petroleum products within built environment and peripherals of Ibadan metropolis over the years. Specifically, the study investigated the differentials in the spatial configurations of petroleum products retail outlets between the core and periurban zones of the metropolis. An attempt was made to determine the explanatory variables that influence the spatial distributional decisions of petroleum products retail outlets in the metropolis. The study equally examined how the supply chain management (SCM) techniques by the different categories of the retail outlet owners influence the efficient and cost effective distribution of petroleum products. Lastly an attempt was made to analyze the relationship between the socio-economic attributes of the haulers and the achievement of compliance to the HSE stipulations guiding the conveyance of petroleum products. The theoretical underpinnings for the research were a derivative of the amalgamation of normative and psychological theories from geography, psychology, SCM and retailing science. Specifically, Expectation Disconfirmation Theory (EDT), Distributive Justice, Central Place Theory (CPT) Theories of Urban Impact (TUI) and Theory of Constraint (ToC) were the theories utilized in the study. For the achievement of the first objective which was to investigate the possible differential in the compliance rate between spatial pattern of fuel retail outlets in the core and peripheral zones of Ibadan metropolis, the first hypothesis of the study (which examined if there was no significant difference in the rate of compliance to the planning authority stipulations guiding the location pattern of petroleum product retail outlets between those located in the built up and xxiv peripheral zones of the city), was tested through the use of buffering and proximity analyses in the ArcMap environment of ArcGIS 10.1, while inferential statistical tool of an independent-samples t-test was conducted to compare the rate of compliance to the stipulations guiding the locations of these outlets in both the core and the peripheral zones. The result from the GIS analysis indicated that 33 (15.56%) out of the 220 outlets in the core zone of the metropolis complied with the planning stipulations guiding the location of fuel retail outlets. For the peripheral zone, out of the 220 fuel retail outlets 24 (10.90%) complied with the stipulations. The result from the t- test which was employed to test the hypothesis indicated that no significant difference existed in the rate of compliance t (263) =-2.66, p = 0.08 between fuel retail outlets in the core zone (M=3.9, SD=1.4) and peripheral zone (M=4.5, SD=1.79). The alternate hypothesis which stated that ―no significant difference existed in the compliance rate between fuel retail outlets located in the two zones‖ is accepted. For the achievement of the second objective of the study which was to analyze the factors which determine the location of fuel retail outlets both in the core and peripheral zones of Ibadan metropolis. All the managers/owners of the 432 fuel retail outlets in the metropolis were sampled out of which 256 questionnaires were retrieved for the purpose of this analysis. The breakdown of the socio-economic characteristics of the sampled respondents showed that the gender distribution showed that 194 (75.78%) of the respondents were males, while 64 (24.22 %) were females. The average age of the sampled population was 33.70 years. The mixed method was employed for the achievement of the second objective of this study. Logistic Regression Model (LRM) was employed to test the hypothesis and the result revealed that the inclusion of the independent variables in the model increased the overall level of it accuracy. The overall significance revealed that the Model Chi- xxv Square, derived from the likelihood fitted is also accurate (X2 = 43.47, df=5, p>.05). The model chi-square value of 43.47 (approximately 44% ) was significant. Thus, the indication is that the model has a good fit in predicting the possibility of a fuel retail outlet being located in the core or peripheral zone of the metropolis as determined by the explanatory variables (the independent variables accounted for about 44% of possible factors which determined whether a fuel retail outlets is located either within the core or peripheral zones of the metropolis. The remaining 56% are factors not considered in the study). The result gotten from the in depth interview sessions corroborated the findings from the tested hypothesis. The third objective was to examine the effects which the supply chain technique employed (either vertically integrated model or third-party arrangement) has on the achievement of efficient and effective distribution of the products. In order to achieve this objective, all the 389 registered members of Petroleum Tanker Drivers (PTD) association who are members of the PTD in the metropolis were sampled, 265 (around 70%) of the distributed questionnaires were retrieved and used for the analysis. In depth interview sessions were also conducted with three different managers of the three major conglomerates in the downstream sector of the Nigerian petroleum sector. The result of one-way between subjects (ANOVA) which was conducted to compare differences in the management and performances of haulage services outsourced to the 3PLS and those run under VIM showed that there was a significant effect of ownership type on management performance (F (2,262) = 60.26, p<.05). The null hypothesis was therefore rejected while the alternate hypothesis was accepted. The findings from the interview sessions posted similar results. The fourth and final objective was to analyze the effect that the socio-economic attributes of the participants (haulers and managers of retail outlets) involved in the distribution of xxvi petroleum products has on the safe, efficient and cost-effective distribution of product and this was done through the use of descriptive statistics, inferential statistics and incisive analysis of the interview sessions. A total number of 265 (70%) out of the 389 registered members of Petroleum Tanker Driver Association (PTDA) participated in the study. Multiple regression analysis (MRA) was used to test this hypothesis. The result from the statistical analysis show that the use of stimulant, work condition, marital status and educational attainment/literacy level have joint influence on compliance (R2 = 0.31, F (4,260) = 29.72, p<.05). On the basis of the foregoing, the hypothesis is thus accepted. The result from the interview sessions confirmed the existence of strong relationship between the explanatory variables and the hypothetical dependant variable. The study recommended a review of the planning processes guiding the establishment of fuel retail outlets. The study also advocated that retailers should endeavour to have stronger control over the supply chain of their products this could done by investing more in VIM rather than outsourcing such functions to 3PLs. This will help in better business performances. Government agencies in charge of monitoring drug abuse among haulers are advised to be more proactive by the duo of prevention and punishment strategies. This should include advocacy campaign against drug abuse. Different ranges of punishments should also be meted out for individual haulers found culpable.
- Full Text:
- Date Issued: 2019
- Authors: Ajayi, Adeyinka Peter
- Date: 2019
- Subjects: Petroleum products
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/19065 , vital:40090
- Description: This study analyzed the effects that spatial arrangement of petroleum products retail outlets and the supply chain management techniques employed for products distribution (for both intra city and intercity shipments) have on the retailing dynamism of petroleum products within built environment and peripherals of Ibadan metropolis over the years. Specifically, the study investigated the differentials in the spatial configurations of petroleum products retail outlets between the core and periurban zones of the metropolis. An attempt was made to determine the explanatory variables that influence the spatial distributional decisions of petroleum products retail outlets in the metropolis. The study equally examined how the supply chain management (SCM) techniques by the different categories of the retail outlet owners influence the efficient and cost effective distribution of petroleum products. Lastly an attempt was made to analyze the relationship between the socio-economic attributes of the haulers and the achievement of compliance to the HSE stipulations guiding the conveyance of petroleum products. The theoretical underpinnings for the research were a derivative of the amalgamation of normative and psychological theories from geography, psychology, SCM and retailing science. Specifically, Expectation Disconfirmation Theory (EDT), Distributive Justice, Central Place Theory (CPT) Theories of Urban Impact (TUI) and Theory of Constraint (ToC) were the theories utilized in the study. For the achievement of the first objective which was to investigate the possible differential in the compliance rate between spatial pattern of fuel retail outlets in the core and peripheral zones of Ibadan metropolis, the first hypothesis of the study (which examined if there was no significant difference in the rate of compliance to the planning authority stipulations guiding the location pattern of petroleum product retail outlets between those located in the built up and xxiv peripheral zones of the city), was tested through the use of buffering and proximity analyses in the ArcMap environment of ArcGIS 10.1, while inferential statistical tool of an independent-samples t-test was conducted to compare the rate of compliance to the stipulations guiding the locations of these outlets in both the core and the peripheral zones. The result from the GIS analysis indicated that 33 (15.56%) out of the 220 outlets in the core zone of the metropolis complied with the planning stipulations guiding the location of fuel retail outlets. For the peripheral zone, out of the 220 fuel retail outlets 24 (10.90%) complied with the stipulations. The result from the t- test which was employed to test the hypothesis indicated that no significant difference existed in the rate of compliance t (263) =-2.66, p = 0.08 between fuel retail outlets in the core zone (M=3.9, SD=1.4) and peripheral zone (M=4.5, SD=1.79). The alternate hypothesis which stated that ―no significant difference existed in the compliance rate between fuel retail outlets located in the two zones‖ is accepted. For the achievement of the second objective of the study which was to analyze the factors which determine the location of fuel retail outlets both in the core and peripheral zones of Ibadan metropolis. All the managers/owners of the 432 fuel retail outlets in the metropolis were sampled out of which 256 questionnaires were retrieved for the purpose of this analysis. The breakdown of the socio-economic characteristics of the sampled respondents showed that the gender distribution showed that 194 (75.78%) of the respondents were males, while 64 (24.22 %) were females. The average age of the sampled population was 33.70 years. The mixed method was employed for the achievement of the second objective of this study. Logistic Regression Model (LRM) was employed to test the hypothesis and the result revealed that the inclusion of the independent variables in the model increased the overall level of it accuracy. The overall significance revealed that the Model Chi- xxv Square, derived from the likelihood fitted is also accurate (X2 = 43.47, df=5, p>.05). The model chi-square value of 43.47 (approximately 44% ) was significant. Thus, the indication is that the model has a good fit in predicting the possibility of a fuel retail outlet being located in the core or peripheral zone of the metropolis as determined by the explanatory variables (the independent variables accounted for about 44% of possible factors which determined whether a fuel retail outlets is located either within the core or peripheral zones of the metropolis. The remaining 56% are factors not considered in the study). The result gotten from the in depth interview sessions corroborated the findings from the tested hypothesis. The third objective was to examine the effects which the supply chain technique employed (either vertically integrated model or third-party arrangement) has on the achievement of efficient and effective distribution of the products. In order to achieve this objective, all the 389 registered members of Petroleum Tanker Drivers (PTD) association who are members of the PTD in the metropolis were sampled, 265 (around 70%) of the distributed questionnaires were retrieved and used for the analysis. In depth interview sessions were also conducted with three different managers of the three major conglomerates in the downstream sector of the Nigerian petroleum sector. The result of one-way between subjects (ANOVA) which was conducted to compare differences in the management and performances of haulage services outsourced to the 3PLS and those run under VIM showed that there was a significant effect of ownership type on management performance (F (2,262) = 60.26, p<.05). The null hypothesis was therefore rejected while the alternate hypothesis was accepted. The findings from the interview sessions posted similar results. The fourth and final objective was to analyze the effect that the socio-economic attributes of the participants (haulers and managers of retail outlets) involved in the distribution of xxvi petroleum products has on the safe, efficient and cost-effective distribution of product and this was done through the use of descriptive statistics, inferential statistics and incisive analysis of the interview sessions. A total number of 265 (70%) out of the 389 registered members of Petroleum Tanker Driver Association (PTDA) participated in the study. Multiple regression analysis (MRA) was used to test this hypothesis. The result from the statistical analysis show that the use of stimulant, work condition, marital status and educational attainment/literacy level have joint influence on compliance (R2 = 0.31, F (4,260) = 29.72, p<.05). On the basis of the foregoing, the hypothesis is thus accepted. The result from the interview sessions confirmed the existence of strong relationship between the explanatory variables and the hypothetical dependant variable. The study recommended a review of the planning processes guiding the establishment of fuel retail outlets. The study also advocated that retailers should endeavour to have stronger control over the supply chain of their products this could done by investing more in VIM rather than outsourcing such functions to 3PLs. This will help in better business performances. Government agencies in charge of monitoring drug abuse among haulers are advised to be more proactive by the duo of prevention and punishment strategies. This should include advocacy campaign against drug abuse. Different ranges of punishments should also be meted out for individual haulers found culpable.
- Full Text:
- Date Issued: 2019