Examining the nature of entrepreneurship within the towns and rural areas of Sakhisizwe Local Municipality, Eastern Cape
- Authors: Maliwa, Noluvuyo
- Date: 2022-11
- Subjects: Entrepreneurship , Developing countries--Economic conditions , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27555 , vital:69315
- Description: Entrepreneurship plays an important role in societies around the world because it supports economic growth and creates job opportunities. This study investigated the nature of entrepreneurship in three distinct parts of Sakhisizwe Local Municipality, including a town within Sakhisizwe’s former homeland area, rural communities within its former homeland area, and a town within an area characterised by large-scale commercial farms. The study sought to establish the share of adults in the different parts of the municipality involved in entrepreneurship, to identify factors that contribute to the decision to become an entrepreneur, and to examine strategies pursued by, and challenges experienced, different types of entrepreneurs. The study involved a random sample of 362 respondents and both quantitative and qualitative data analysis. Among the main findings is that the proportion of adults involved in enterprise in Sakhisizwe is higher than found by other studies for South Africa as a whole, but is especially high for those living in the town in the former homeland area. While those residing in rural communities also engage in enterprise, they are generally compelled to practice their enterprises in town, thus have the disadvantage of needing frequent transport. While residing in the town in the commercial farming area is not disadvantageous in the same way, the challenge is that the town itself is able to support relatively few entrepreneurs due to fewer people coming to town for their shopping. , Thesis (MSci) -- Faculty of Science and Agricultures, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Maliwa, Noluvuyo
- Date: 2022-11
- Subjects: Entrepreneurship , Developing countries--Economic conditions , Small business
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27555 , vital:69315
- Description: Entrepreneurship plays an important role in societies around the world because it supports economic growth and creates job opportunities. This study investigated the nature of entrepreneurship in three distinct parts of Sakhisizwe Local Municipality, including a town within Sakhisizwe’s former homeland area, rural communities within its former homeland area, and a town within an area characterised by large-scale commercial farms. The study sought to establish the share of adults in the different parts of the municipality involved in entrepreneurship, to identify factors that contribute to the decision to become an entrepreneur, and to examine strategies pursued by, and challenges experienced, different types of entrepreneurs. The study involved a random sample of 362 respondents and both quantitative and qualitative data analysis. Among the main findings is that the proportion of adults involved in enterprise in Sakhisizwe is higher than found by other studies for South Africa as a whole, but is especially high for those living in the town in the former homeland area. While those residing in rural communities also engage in enterprise, they are generally compelled to practice their enterprises in town, thus have the disadvantage of needing frequent transport. While residing in the town in the commercial farming area is not disadvantageous in the same way, the challenge is that the town itself is able to support relatively few entrepreneurs due to fewer people coming to town for their shopping. , Thesis (MSci) -- Faculty of Science and Agricultures, 2022
- Full Text:
- Date Issued: 2022-11
Insights into the drivers and impact of climate change and climate change adaptation in the Eastern Cape, South Africa: the case of Amathole District Municipality
- Authors: Gwala, Lindokuhle
- Date: 2022-11
- Subjects: Climatic changes , Climatic factors , Global environmental change
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27832 , vital:69945
- Description: Climate change is a threat to communal livestock production, causing increases in the rate and intensity of droughts, floods, pests and diseases, and thus subjecting communal livestock production to vulnerability. Communal farmers rely on rain-fed agriculture and are usually too poorly resourced to cope with the frequency of climate-related events that may be expected in the future. Response and adaptation is vital to ensure the sustainability of livestock production, particularly since it is the main source of survival in communal areas. The Eastern Cape Provincial Policy on Climate Change was introduced in 2010 to facilitate a coordinated approach that assists farmers to respond, adapt and mitigate climate change. The study examines the implementation of the policy to identify farmers’ perceptions of the response rate prior to, during and after climate change disasters. In addition, the study establishes the characteristics of livestock production in the study area, seeking to ascertain how communal livestock farmers CLFs are adapting their practices to ensure sustainable livestock production in the face of climate change. In order to make informed decisions on coping strategies, farmers require access to information on climate change. The study therefore examines the communication channels used by farmers to access such information. Since food security is under threat, the study also assesses the effects of climate change on food security among the CLFs. Multi stage sampling was used to select 388 communal livestock farmers in three local municipalities in Amathole District Municipality. A cross-sectional survey was carried out in five communities randomly selected in the three local municipalities, with data collected by means of a semi-structured questionnaire. Descriptive statistics, inferential statistics, principal component analysis and regression methods were used to analyse the data. The study reveals that communal livestock farmers perceive a poor response rate from extension services before, during and after disasters, and that they have poor access to support materials. All of the respondents practised uncontrolled breeding, attributed to a lack of infrastructure such as fencing. Most farmers kept cattle for income generation. The major constraints of cattle production were diseases and pests. CLFs employed dipping, rotational grazing, water tanks, veld burning and the sale of animals as the main strategies to cope with climate change. CLFs access climate change information through multiple channels. The main sources were other farmers and media such as radio and television, although language barriers hampered full understanding of information conveyed about climate chnage. Farmer-to-farmer contact was a central aspect of the CLFs’ lives that could be better employed in the dissemination of climate change information. The results suggest a positive relationship between diversity of species kept and food security. Assets, the social safety net (mainly grants) and adaptive capacity indicators positively and significantly impacted households’ resilience to food insecurity. The study recommends that the capacity of communal livestock farmers on effective mitigating strategies be improved, making use of mass media; that more work be done by extension services to prepare farmers for adverse events and that relief materials disseminated during periods of disaster be tagged “national emergency” to speed up distribution and use. There is an urgent need for adequate and timely provision of climate change information that will help CLFs to make more effective use of their resources in the face of climate change. Agricultural extension services should address challenges associated with breeding practices, disaster response and adult illiteracy to promote better adaptive capacity and ensure food security among this vulnerable cohort. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Gwala, Lindokuhle
- Date: 2022-11
- Subjects: Climatic changes , Climatic factors , Global environmental change
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27832 , vital:69945
- Description: Climate change is a threat to communal livestock production, causing increases in the rate and intensity of droughts, floods, pests and diseases, and thus subjecting communal livestock production to vulnerability. Communal farmers rely on rain-fed agriculture and are usually too poorly resourced to cope with the frequency of climate-related events that may be expected in the future. Response and adaptation is vital to ensure the sustainability of livestock production, particularly since it is the main source of survival in communal areas. The Eastern Cape Provincial Policy on Climate Change was introduced in 2010 to facilitate a coordinated approach that assists farmers to respond, adapt and mitigate climate change. The study examines the implementation of the policy to identify farmers’ perceptions of the response rate prior to, during and after climate change disasters. In addition, the study establishes the characteristics of livestock production in the study area, seeking to ascertain how communal livestock farmers CLFs are adapting their practices to ensure sustainable livestock production in the face of climate change. In order to make informed decisions on coping strategies, farmers require access to information on climate change. The study therefore examines the communication channels used by farmers to access such information. Since food security is under threat, the study also assesses the effects of climate change on food security among the CLFs. Multi stage sampling was used to select 388 communal livestock farmers in three local municipalities in Amathole District Municipality. A cross-sectional survey was carried out in five communities randomly selected in the three local municipalities, with data collected by means of a semi-structured questionnaire. Descriptive statistics, inferential statistics, principal component analysis and regression methods were used to analyse the data. The study reveals that communal livestock farmers perceive a poor response rate from extension services before, during and after disasters, and that they have poor access to support materials. All of the respondents practised uncontrolled breeding, attributed to a lack of infrastructure such as fencing. Most farmers kept cattle for income generation. The major constraints of cattle production were diseases and pests. CLFs employed dipping, rotational grazing, water tanks, veld burning and the sale of animals as the main strategies to cope with climate change. CLFs access climate change information through multiple channels. The main sources were other farmers and media such as radio and television, although language barriers hampered full understanding of information conveyed about climate chnage. Farmer-to-farmer contact was a central aspect of the CLFs’ lives that could be better employed in the dissemination of climate change information. The results suggest a positive relationship between diversity of species kept and food security. Assets, the social safety net (mainly grants) and adaptive capacity indicators positively and significantly impacted households’ resilience to food insecurity. The study recommends that the capacity of communal livestock farmers on effective mitigating strategies be improved, making use of mass media; that more work be done by extension services to prepare farmers for adverse events and that relief materials disseminated during periods of disaster be tagged “national emergency” to speed up distribution and use. There is an urgent need for adequate and timely provision of climate change information that will help CLFs to make more effective use of their resources in the face of climate change. Agricultural extension services should address challenges associated with breeding practices, disaster response and adult illiteracy to promote better adaptive capacity and ensure food security among this vulnerable cohort. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
Spatial assessment of riparian vegetation condition in relation to water quality: a case of the Keiskamma River, Eastern Cape Province, South Africa
- Authors: Teyise, Anda
- Date: 2022-11
- Subjects: Water quality , Riparian plants , Stream health
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27679 , vital:69393
- Description: Riparian vegetation plays several roles in ecological functioning, such as improving water quality because it can filtrate the sediments and provides stability on the floodplain. The condition of riparian vegetation can serve to provide information regarding river condition. The main purpose of this study was to investigate the extent to which water quality level of the Keiskamma River can be explained by the riparian vegetation density patterns. This study used Sentinel-2 Multi-Spectral Instrument (MSI) satellite image to assess spatial patterns in riparian vegetation condition. The Normalized Difference Vegetation Index (NDVI) was generated from the Sentinel-2 imagery and was used as the base from which riparian vegetation density classes were obtained through the supervised image classification technique. The image classification accuracy assessment was caried out to verify and validate the accuracy of riparian vegetation density classes. This technique produced the overall accuracy (OA) classification of 83.72 percent. The riverine water quality parameters were measured on the randomly surveyed sites using the Premium Series PC60 5-in-1 Water Quality Tester. High density of riparian vegetation were found in the upper course of the river. The low-density riparian vegetation dominates the middle course of the river while the lower part of the river contains a mixture of the three riparian vegetation conditions. The one-sample t-test statistical technique was carried out to determine the spatial pattern of water quality parameters. The t-test results revealed the significant variation in water pH, with the p-value of 0.00. However, t-test results also showed insignificant variations in water Total Dissolved Solids (TDS) and electrical conductivity (EC), with p-values of 0.117 0.059 and 0.059 respectively. The linear regression was used to determine the relationship between riparian vegetation and water quality. In this case, the NDVI values were used as surrogate for riparian vegetation condition. The results showed insignificant relationships between NDVI and water pH (r2 = 0.00), NDVI and water TDS (r2 = 0.09), and NDVI and water EC (r2 = 0.09) along the Keiskamma River. In view of the findings obtained from this study “spatial differences in riparian vegetation along the lateral and longitudinal dimensions of the Keiskamma River denote spatial variations in water quality levels”, is rejected. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Teyise, Anda
- Date: 2022-11
- Subjects: Water quality , Riparian plants , Stream health
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27679 , vital:69393
- Description: Riparian vegetation plays several roles in ecological functioning, such as improving water quality because it can filtrate the sediments and provides stability on the floodplain. The condition of riparian vegetation can serve to provide information regarding river condition. The main purpose of this study was to investigate the extent to which water quality level of the Keiskamma River can be explained by the riparian vegetation density patterns. This study used Sentinel-2 Multi-Spectral Instrument (MSI) satellite image to assess spatial patterns in riparian vegetation condition. The Normalized Difference Vegetation Index (NDVI) was generated from the Sentinel-2 imagery and was used as the base from which riparian vegetation density classes were obtained through the supervised image classification technique. The image classification accuracy assessment was caried out to verify and validate the accuracy of riparian vegetation density classes. This technique produced the overall accuracy (OA) classification of 83.72 percent. The riverine water quality parameters were measured on the randomly surveyed sites using the Premium Series PC60 5-in-1 Water Quality Tester. High density of riparian vegetation were found in the upper course of the river. The low-density riparian vegetation dominates the middle course of the river while the lower part of the river contains a mixture of the three riparian vegetation conditions. The one-sample t-test statistical technique was carried out to determine the spatial pattern of water quality parameters. The t-test results revealed the significant variation in water pH, with the p-value of 0.00. However, t-test results also showed insignificant variations in water Total Dissolved Solids (TDS) and electrical conductivity (EC), with p-values of 0.117 0.059 and 0.059 respectively. The linear regression was used to determine the relationship between riparian vegetation and water quality. In this case, the NDVI values were used as surrogate for riparian vegetation condition. The results showed insignificant relationships between NDVI and water pH (r2 = 0.00), NDVI and water TDS (r2 = 0.09), and NDVI and water EC (r2 = 0.09) along the Keiskamma River. In view of the findings obtained from this study “spatial differences in riparian vegetation along the lateral and longitudinal dimensions of the Keiskamma River denote spatial variations in water quality levels”, is rejected. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
The classification performance of ensemble decision tree classifiers: a case study of detecting fraud in credit card transactions
- Authors: Chogugudza, Mcdonald
- Date: 2022-11
- Subjects: fraud , Commercial fraud , Accounting fraud
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27590 , vital:69317
- Description: In this dissertation, we propose ensemble decision tree classifiers as an ideal classification technique for solving the problem of fraud in the domain of credit card transactions. Ensemble tree classifiers have been applied in many areas like speech recognition, image recognition and medical diagnostics and have shown excellent results. At the centre of fraud, credit card fraud has been a major concern. The rise in credit card fraud is largely attributed to the nature in which it can be done. A fraudster does not need to always be physically present to commit fraud making it the number one target for criminals. Card-Not-Present refers to this type of fraud where an electronic transaction can be conducted without the need for a client to be present. This can be done via telephonic calls or the web. To be able to come up with better classifiers it was important for the researcher to first investigate what causes misclassifications in fraud detection systems. A systematic literature review was done to uncover the factors that have been identified as causes of misclassifications. It was discovered that many factors lead to misclassifications and several authors have proposed techniques to handle these factors. However, there is no universal techniques for addressing factors that lead to misclassifications as different domains have different datasets which require different techniques. This study investigates how parameters involved in modelling fraud detection systems impact the classification performance of ensemble decision tree classifiers. The factors that were investigated include sample size, sampling technique, learning method and choice of split criterion and how they affect classification performance. A series of experiments were conducted to investigate how the aforementioned factors contributed to better classifiers. Ecommerce data from Vesta corporation made available on Kaggle was used in the experiments. The data was split into two sets, one for training the models and the other for testing the performance of the models. Accuracy, confusion matrix, precision and recall were used as performance measures. Our results showed that a larger sample size resulted in better classifiers. This is attributed to models having more instances to learn from which covers most patterns of fraudulent transactions. The sampling technique was shown to be pivotal in classification performance as under sampling showed a great reduction in performance as it achieved a maximum accuracy of 89.6223 while oversampling produced increased performance with maximum accuracy of 99.9531. Furthermore, our results showed that the choice of split criterion impacts the performance of ensemble tree classifiers. The use of entropy as the choice of split criterion resulted in better classifiers compared to the use of the Gini index. However, the downside is that entropy requires more time to execute compared to the Gini index. Lastly, the learning method proved to impact the performance of ensemble classifiers. Models that used supervised learning had better performance compared to those that use unsupervised learning in detecting credit card fraud. The conclusions from this research are insightful when designing fraud detection systems that use ensemble decision tree classifiers as base learners. , Thesis (Msci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
- Authors: Chogugudza, Mcdonald
- Date: 2022-11
- Subjects: fraud , Commercial fraud , Accounting fraud
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27590 , vital:69317
- Description: In this dissertation, we propose ensemble decision tree classifiers as an ideal classification technique for solving the problem of fraud in the domain of credit card transactions. Ensemble tree classifiers have been applied in many areas like speech recognition, image recognition and medical diagnostics and have shown excellent results. At the centre of fraud, credit card fraud has been a major concern. The rise in credit card fraud is largely attributed to the nature in which it can be done. A fraudster does not need to always be physically present to commit fraud making it the number one target for criminals. Card-Not-Present refers to this type of fraud where an electronic transaction can be conducted without the need for a client to be present. This can be done via telephonic calls or the web. To be able to come up with better classifiers it was important for the researcher to first investigate what causes misclassifications in fraud detection systems. A systematic literature review was done to uncover the factors that have been identified as causes of misclassifications. It was discovered that many factors lead to misclassifications and several authors have proposed techniques to handle these factors. However, there is no universal techniques for addressing factors that lead to misclassifications as different domains have different datasets which require different techniques. This study investigates how parameters involved in modelling fraud detection systems impact the classification performance of ensemble decision tree classifiers. The factors that were investigated include sample size, sampling technique, learning method and choice of split criterion and how they affect classification performance. A series of experiments were conducted to investigate how the aforementioned factors contributed to better classifiers. Ecommerce data from Vesta corporation made available on Kaggle was used in the experiments. The data was split into two sets, one for training the models and the other for testing the performance of the models. Accuracy, confusion matrix, precision and recall were used as performance measures. Our results showed that a larger sample size resulted in better classifiers. This is attributed to models having more instances to learn from which covers most patterns of fraudulent transactions. The sampling technique was shown to be pivotal in classification performance as under sampling showed a great reduction in performance as it achieved a maximum accuracy of 89.6223 while oversampling produced increased performance with maximum accuracy of 99.9531. Furthermore, our results showed that the choice of split criterion impacts the performance of ensemble tree classifiers. The use of entropy as the choice of split criterion resulted in better classifiers compared to the use of the Gini index. However, the downside is that entropy requires more time to execute compared to the Gini index. Lastly, the learning method proved to impact the performance of ensemble classifiers. Models that used supervised learning had better performance compared to those that use unsupervised learning in detecting credit card fraud. The conclusions from this research are insightful when designing fraud detection systems that use ensemble decision tree classifiers as base learners. , Thesis (Msci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-11
Isolation, characterisation and biological evaluation of Tithonia diversifolia and Tephrosia vogelii as sources of Anti-oxidant and Pesticide
- Kerebba, Nasifu https://orcid.org/0000-0003-3700-3937
- Authors: Kerebba, Nasifu https://orcid.org/0000-0003-3700-3937
- Date: 2022-08
- Subjects: Tephrosia vogelii , Tephrosia , Pesticides
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27821 , vital:69943
- Description: This study aimed at evaluating chemically the pesticidal and antioxidant activities of Tithonia diversifolia Hemsland Tephrosia vogelii Hook f. In the study, the composition of essential oils and non-volatile substances was evaluated by modern analytical tools. The essential oils were characterised using Gas chromatography GC mass spectrometry mass spectrometry GC MS MS, GC and multivariate techniques. While phenolic compounds of T. diversifolia were comprehensively characterised using Ultra high performance liquid-phase chromatography coupled to a tandem mass spectrometer with electrospray ionisation UHPLC ESI MS MS. Both the essential oils and non-volatile components of the plant materials were evaluated for repellency, fumigant toxicity, contact toxicity and antifeedant potential in either a choice or no choice experiments. The non-volatile substances were evaluated for antioxidant properties. Using activity-guided isolation, three known compounds, a one pimarane diterpene type compound; sandaracopimaradiene-1α,9α-diol, a sesquiterpene lactone; deacetylviguiestenin and a caffeic acid derivative; 3 4 O caffeoyloxy methyl 2-methyloxirane-2-carboxylic acid were obtained from T. diversifolia. The compounds were characterised by spectral methods; 1D and 2D nuclear magnetic resonance NMR, Fourier transform Infra-red spectroscopy FTIR and mass spectrometry MS. Characterisation of essential oils revealed three chemotypes that were found to grow at different places of eastern Uganda. Based on the profiles of the compounds of the farnesene family, results showed that farnesol was a major constituent in the oil of chemotype 1 while springene compounds β-springene and α-springene and the β-farnesene were widely expressed in chemotype 2. The third chemotype was a mixed hybrid of both farnesol and the springene chemotypes. In all the chemotypes, alkylbenzenes; o-xylene, m-xylene and ethylbenzene were in huge amounts as other significant components in the oil. 1,4- dihydroxy-p-menth-2-ene, 5,9-undecadien-2-one, 6,10-dimethyl, and 3-cyclohexen-1- carboxaldehyde,3,4-dimethyl were other most significant chemical constituents of the three chemotypes. The presence of chemical variation in the components of T. vogelii essential oil showed that the fumigant and repellency efficacy of this plant against Sitophilus zeamais Motschulsky were undermined. However, all the chemotypes of T. vogelii essential oil could show repellence and fumigant toxicity against S. zeamais. The comparison between insecticidal and repellent effects of the essential oils of chemotype 3 of T. vogelii with that of T. diversifolia was done. Results indicated that the former could be promoted more for contact toxicity effect while T. diversifolia better suits fumigation effects against S. zeamais. Investigation of the feeding deterrence of both volatile and non-volatile substances of T. diversifolia leaves revealed that its essential oil did not show significant antifeedant activity at a dose of 0.29 μL mg of flour disks. The crude extract, some fractions and the isolated compounds demonstrated feeding deterrence activity against S. zeamais. The feeding deterrence index of sandarac copimaradiene- 1α,9α-diol was 81.19 5.94 percent at 0.1percent w w 1 mg g food compared to 97.45 0.43 percentage for Neemazal extract 10 percent azadirachtin positive control at 10w w 100 mgg food. The EC50 of deacetylviguiestin, 3 4 O caffeoyloxy methyl 2 methyloxirane 2 carboxylic acid and azadirachtin commercial antifeedant against S. zeamais were 22140.23 9103.29, 3654.28 2715.09 and 14.59 5.59 ppm respectively. Although these compounds showed less activity against S. zeamais than azadirachtin, their antifeedant activities were very significant and can be valuable alternatives. UHPLC DAD ESI-MS MS characterisation of fractions of T. diversifolia led to the identification of 7 novel hydroxycinnamates; 4-O 1 O caffeoylglucosyl quinic acid, 4 O caffeoyl 2 hydroxy 3 methylbutanoic acid, 4-O-caffeoyl-2-hydroxybutanoic acid, 3,4 dihydroxyphenyl-4-O-caffeoyl-2-hydroxybutanoate, 4-vinylphenyl 4 O caffeoyl 2-hydroxy 3 methylbutanoate, 4 O caffeoyl-caffeoyloxymethyl 2 hydroxy 3 methylbutanoate, 4 O-caffeoyl 2 2 3,4 dihydroxyphenyl acetoyloxy 3-methylbutanoic acid from T. diversifolia leaves that had not been previously reported in nature. Their structures have been assigned based on the unique MS MS fragmentation patterns for each of the compounds in a switching negative or positive ionisation mode and deduction from 1D 1H and 13C NMR of similar compound. In total, 55 phenolic compounds from aqueous fractions of T. diversifolia have been identified including 4 hydroxybenzoic acids, 19 hydroxycinnamic acids, 22 flavonoids, 1 saponin triterpenoid and 9 coumarins and furocoumarins. The present study further showed that the DPPH radical scavenging effect and reducing power antioxidant activity of tested samples of T. diversifolia showed a moderate correlation with the phenolic content present in these samples. This implied that the antioxidant potential was just partly attributed to its phenolic content. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-08
- Authors: Kerebba, Nasifu https://orcid.org/0000-0003-3700-3937
- Date: 2022-08
- Subjects: Tephrosia vogelii , Tephrosia , Pesticides
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27821 , vital:69943
- Description: This study aimed at evaluating chemically the pesticidal and antioxidant activities of Tithonia diversifolia Hemsland Tephrosia vogelii Hook f. In the study, the composition of essential oils and non-volatile substances was evaluated by modern analytical tools. The essential oils were characterised using Gas chromatography GC mass spectrometry mass spectrometry GC MS MS, GC and multivariate techniques. While phenolic compounds of T. diversifolia were comprehensively characterised using Ultra high performance liquid-phase chromatography coupled to a tandem mass spectrometer with electrospray ionisation UHPLC ESI MS MS. Both the essential oils and non-volatile components of the plant materials were evaluated for repellency, fumigant toxicity, contact toxicity and antifeedant potential in either a choice or no choice experiments. The non-volatile substances were evaluated for antioxidant properties. Using activity-guided isolation, three known compounds, a one pimarane diterpene type compound; sandaracopimaradiene-1α,9α-diol, a sesquiterpene lactone; deacetylviguiestenin and a caffeic acid derivative; 3 4 O caffeoyloxy methyl 2-methyloxirane-2-carboxylic acid were obtained from T. diversifolia. The compounds were characterised by spectral methods; 1D and 2D nuclear magnetic resonance NMR, Fourier transform Infra-red spectroscopy FTIR and mass spectrometry MS. Characterisation of essential oils revealed three chemotypes that were found to grow at different places of eastern Uganda. Based on the profiles of the compounds of the farnesene family, results showed that farnesol was a major constituent in the oil of chemotype 1 while springene compounds β-springene and α-springene and the β-farnesene were widely expressed in chemotype 2. The third chemotype was a mixed hybrid of both farnesol and the springene chemotypes. In all the chemotypes, alkylbenzenes; o-xylene, m-xylene and ethylbenzene were in huge amounts as other significant components in the oil. 1,4- dihydroxy-p-menth-2-ene, 5,9-undecadien-2-one, 6,10-dimethyl, and 3-cyclohexen-1- carboxaldehyde,3,4-dimethyl were other most significant chemical constituents of the three chemotypes. The presence of chemical variation in the components of T. vogelii essential oil showed that the fumigant and repellency efficacy of this plant against Sitophilus zeamais Motschulsky were undermined. However, all the chemotypes of T. vogelii essential oil could show repellence and fumigant toxicity against S. zeamais. The comparison between insecticidal and repellent effects of the essential oils of chemotype 3 of T. vogelii with that of T. diversifolia was done. Results indicated that the former could be promoted more for contact toxicity effect while T. diversifolia better suits fumigation effects against S. zeamais. Investigation of the feeding deterrence of both volatile and non-volatile substances of T. diversifolia leaves revealed that its essential oil did not show significant antifeedant activity at a dose of 0.29 μL mg of flour disks. The crude extract, some fractions and the isolated compounds demonstrated feeding deterrence activity against S. zeamais. The feeding deterrence index of sandarac copimaradiene- 1α,9α-diol was 81.19 5.94 percent at 0.1percent w w 1 mg g food compared to 97.45 0.43 percentage for Neemazal extract 10 percent azadirachtin positive control at 10w w 100 mgg food. The EC50 of deacetylviguiestin, 3 4 O caffeoyloxy methyl 2 methyloxirane 2 carboxylic acid and azadirachtin commercial antifeedant against S. zeamais were 22140.23 9103.29, 3654.28 2715.09 and 14.59 5.59 ppm respectively. Although these compounds showed less activity against S. zeamais than azadirachtin, their antifeedant activities were very significant and can be valuable alternatives. UHPLC DAD ESI-MS MS characterisation of fractions of T. diversifolia led to the identification of 7 novel hydroxycinnamates; 4-O 1 O caffeoylglucosyl quinic acid, 4 O caffeoyl 2 hydroxy 3 methylbutanoic acid, 4-O-caffeoyl-2-hydroxybutanoic acid, 3,4 dihydroxyphenyl-4-O-caffeoyl-2-hydroxybutanoate, 4-vinylphenyl 4 O caffeoyl 2-hydroxy 3 methylbutanoate, 4 O caffeoyl-caffeoyloxymethyl 2 hydroxy 3 methylbutanoate, 4 O-caffeoyl 2 2 3,4 dihydroxyphenyl acetoyloxy 3-methylbutanoic acid from T. diversifolia leaves that had not been previously reported in nature. Their structures have been assigned based on the unique MS MS fragmentation patterns for each of the compounds in a switching negative or positive ionisation mode and deduction from 1D 1H and 13C NMR of similar compound. In total, 55 phenolic compounds from aqueous fractions of T. diversifolia have been identified including 4 hydroxybenzoic acids, 19 hydroxycinnamic acids, 22 flavonoids, 1 saponin triterpenoid and 9 coumarins and furocoumarins. The present study further showed that the DPPH radical scavenging effect and reducing power antioxidant activity of tested samples of T. diversifolia showed a moderate correlation with the phenolic content present in these samples. This implied that the antioxidant potential was just partly attributed to its phenolic content. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-08
Reservoir rock preoperty and hydrocarbon potentieal in the offshore gamtoos and algoa basins, South Africa
- Authors: Mokoele, Salmina Phuti
- Date: 2022-07
- Subjects: Hydrocarbon reservoirs , South Africa -- Gamtoos River , Gamtoos Estuary (South Africa)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27981 , vital:71409
- Description: Various research methods were employed to evaluate reservoir rock properties and source rock maturity for hydrocarbon potential in the offshore Gamtoos and Algoa basins, including lithostratigraphy, facies analysis, petrography, geophysics, geochemistry and basin modelling. Sedimentary facies were identified in the Gamtoos Basin along with their inferred depositional systems, mainly from the synrift I and II successions. This was also supplemented by lithostratigraphic evaluation of 12 wells across the study area. Facies analysis was applied to describe different rock types with depositional signatures by using the following parameters: grain fabric/texture, primary sedimentary structures, and fossil contents. Different types of lithofacies and biofacies were recorded indicating variations in bioturbation from low to high intensities. The results revealed a total of 15 types of facies from five cores, which were further subdivided into 8 types of sandstones, 3 types of siltstones, 3 types of mudstones and 1 type of conglomerate. Furthermore, five facies associations FA1 to FA5 were recognized from core evaluation: hemipelagite facies association, fine-grained, thinly bedded heterolithic sandstone-mudstone facies association (low-density turbidity flows), medium to coarse grained massive sandstone facies association high-density turbidity flows, debrites hybrid facies association and coarse grained conglomerate facies association. In terms of lithostratigraphic sequence, they correspond with fine- to medium-grained massive sandstone units of the Ta division, horizontal laminated sandstone units of the Tb division, fine to medium grained wavy laminated sandstone units of the Tc division, parallel laminated siltstones intercalated with fine grained ripple and lenticular sandstones of the Tc to Td divisions and fine grained massive, bedded siltstone units of the Te division. Both the Gamtoos and Algoa offshore basins comprise wells with proven source rock presence. Results from geochemical evaluations have revealed the presence of significant quantities of Late Jurassic to Early Cretaceous (Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian) source rock intervals. The wells used for this research intersected a total of 25 source rocks across the various age groups with an average thickness of 70 m. Source rocks with hydrocarbon potentials were intersected at Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian successions. The source rocks indicate good to excellent quality of hydrocarbons with the potential to generate both oil to gas. For example, Tithonian source rock shows a tremendous petroleum generation potential with mostly type II (oil prone) and type II/III (oil to gas prone) kerogen. The data suggests that the Tithonian source rock was mainly deposited in marine depositional settings with planktons being the main source of kerogen. Some of the kerogen could have originated from limited quantities of algae (marine settings) and terrestrial plants. The source rock indicates a potential to generate variable hydrocarbons from oil, wet gas and dry gas. The Kimmeridgian and Tithonian source rocks range from main oil window to post gas mature zone. In the south-eastern part of the offshore Gamtoos Basin, deep marine shale source rocks were deposited between the Kimmeridgian and Tithonian age and these marine conditions continued throughout the synrift stage. The Algoa Basin indicates the deposition of deep-water shale source rocks resulting from a transgression period. The Berriasian source rock indicates a range in maturity from the early oil to gas windows in the Gamtoos graben between 126 Ma and present day. The source rock further shows a maximum transformation ratio of 100 percent at well Ha-D1 in the Gamtoos Basin. The Valanginian source rock indicates a range in maturity from early to late oil windows in the Algoa Basin with extremely low rates of transformation at a maximum of 24.67 percentage at well Hb-B1. The Hauterivian source rock dominantly plots within the early to main oil windows with vitrinite values between 0.6 and 0.8 percent. Results obtained from this research indicate the presence of moderate to good quality source rocks from the Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian. Majority of the source rocks have type III kerogen which is most likely to generate gas. The study area shows the presence of good quality source rocks with good petroleum generation potentials. The source rocks also show the ability to generate and expel hydrocarbons. The deeper sections of the grabens indicate high maturity levels with source rocks dominantly in the gas and late oil windows while the flanks are indicative of lower maturity stages between early and main oil windows. The best source rocks were mainly intersected and modelled from the synrift section while the upper transitional to drift sections indicate good quality reservoir rocks. The upper sections of the study area show a tremendous improvement in the quality of the reservoirs with porosity levels recorded to be up to 26 percent. The porosity levels increase up to 17 percent at well Ha-B2. This generally improved the potential for good reservoirs in the area from what has been intersected by the wells to the entire study area with the presence of effective traps and seals. The influence of hydrothermal alteration and chlorite cementation is quite low at these shallower sequences which further improved the quality of these reservoirs. Some of the sandstones intersected from the synrift sections range from very fine to coarse grained in texture with very low permeability and porosity due to extensive carbonate cementation, and also affected by hydrothermal alteration resulted from the extensive faulting in the area. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-07
- Authors: Mokoele, Salmina Phuti
- Date: 2022-07
- Subjects: Hydrocarbon reservoirs , South Africa -- Gamtoos River , Gamtoos Estuary (South Africa)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27981 , vital:71409
- Description: Various research methods were employed to evaluate reservoir rock properties and source rock maturity for hydrocarbon potential in the offshore Gamtoos and Algoa basins, including lithostratigraphy, facies analysis, petrography, geophysics, geochemistry and basin modelling. Sedimentary facies were identified in the Gamtoos Basin along with their inferred depositional systems, mainly from the synrift I and II successions. This was also supplemented by lithostratigraphic evaluation of 12 wells across the study area. Facies analysis was applied to describe different rock types with depositional signatures by using the following parameters: grain fabric/texture, primary sedimentary structures, and fossil contents. Different types of lithofacies and biofacies were recorded indicating variations in bioturbation from low to high intensities. The results revealed a total of 15 types of facies from five cores, which were further subdivided into 8 types of sandstones, 3 types of siltstones, 3 types of mudstones and 1 type of conglomerate. Furthermore, five facies associations FA1 to FA5 were recognized from core evaluation: hemipelagite facies association, fine-grained, thinly bedded heterolithic sandstone-mudstone facies association (low-density turbidity flows), medium to coarse grained massive sandstone facies association high-density turbidity flows, debrites hybrid facies association and coarse grained conglomerate facies association. In terms of lithostratigraphic sequence, they correspond with fine- to medium-grained massive sandstone units of the Ta division, horizontal laminated sandstone units of the Tb division, fine to medium grained wavy laminated sandstone units of the Tc division, parallel laminated siltstones intercalated with fine grained ripple and lenticular sandstones of the Tc to Td divisions and fine grained massive, bedded siltstone units of the Te division. Both the Gamtoos and Algoa offshore basins comprise wells with proven source rock presence. Results from geochemical evaluations have revealed the presence of significant quantities of Late Jurassic to Early Cretaceous (Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian) source rock intervals. The wells used for this research intersected a total of 25 source rocks across the various age groups with an average thickness of 70 m. Source rocks with hydrocarbon potentials were intersected at Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian successions. The source rocks indicate good to excellent quality of hydrocarbons with the potential to generate both oil to gas. For example, Tithonian source rock shows a tremendous petroleum generation potential with mostly type II (oil prone) and type II/III (oil to gas prone) kerogen. The data suggests that the Tithonian source rock was mainly deposited in marine depositional settings with planktons being the main source of kerogen. Some of the kerogen could have originated from limited quantities of algae (marine settings) and terrestrial plants. The source rock indicates a potential to generate variable hydrocarbons from oil, wet gas and dry gas. The Kimmeridgian and Tithonian source rocks range from main oil window to post gas mature zone. In the south-eastern part of the offshore Gamtoos Basin, deep marine shale source rocks were deposited between the Kimmeridgian and Tithonian age and these marine conditions continued throughout the synrift stage. The Algoa Basin indicates the deposition of deep-water shale source rocks resulting from a transgression period. The Berriasian source rock indicates a range in maturity from the early oil to gas windows in the Gamtoos graben between 126 Ma and present day. The source rock further shows a maximum transformation ratio of 100 percent at well Ha-D1 in the Gamtoos Basin. The Valanginian source rock indicates a range in maturity from early to late oil windows in the Algoa Basin with extremely low rates of transformation at a maximum of 24.67 percentage at well Hb-B1. The Hauterivian source rock dominantly plots within the early to main oil windows with vitrinite values between 0.6 and 0.8 percent. Results obtained from this research indicate the presence of moderate to good quality source rocks from the Kimmeridgian, Tithonian, Berriasian, Valanginian and Hauterivian. Majority of the source rocks have type III kerogen which is most likely to generate gas. The study area shows the presence of good quality source rocks with good petroleum generation potentials. The source rocks also show the ability to generate and expel hydrocarbons. The deeper sections of the grabens indicate high maturity levels with source rocks dominantly in the gas and late oil windows while the flanks are indicative of lower maturity stages between early and main oil windows. The best source rocks were mainly intersected and modelled from the synrift section while the upper transitional to drift sections indicate good quality reservoir rocks. The upper sections of the study area show a tremendous improvement in the quality of the reservoirs with porosity levels recorded to be up to 26 percent. The porosity levels increase up to 17 percent at well Ha-B2. This generally improved the potential for good reservoirs in the area from what has been intersected by the wells to the entire study area with the presence of effective traps and seals. The influence of hydrothermal alteration and chlorite cementation is quite low at these shallower sequences which further improved the quality of these reservoirs. Some of the sandstones intersected from the synrift sections range from very fine to coarse grained in texture with very low permeability and porosity due to extensive carbonate cementation, and also affected by hydrothermal alteration resulted from the extensive faulting in the area. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-07
Effect of pomegranate (Punica granatum L) peel powder meal on growth performance, gut integrity, haemato-biochemical indices, meat, and bone quality of broiler chickens
- Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of antimicrobial combination therapy options for the management of integron-mediated multidrug resistance in enterococcus species and acinetobacter baumannii from aquatic environment in the Eastern Cape Province, South Africa
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of groundwater potential using geological and geophysical methods in the University of Fort Hare Alice Campus, Eastern Cape Province of South Africa
- Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Adesola, Gbenga Olamide https://orcid.org/0000-0002-4151-5305
- Date: 2022-04
- Subjects: Groundwater , Geology, Structural -- South Africa , Geographical Information Systems
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22490 , vital:52344
- Description: Geological and geophysical methods were used to evaluate the groundwater potential in University of Fort Hare (Alice campus), Eastern Cape Province of South Africa. Methodologies adopted for obtaining these results included a comprehensive literature review, thin section analysis, scanning electron microscopy, Geographical Information Systems (GIS), remote sensing and geophysical investigations (magnetic survey and vertical electrical sounding). The geology of the study area belongs to the Balfour Formation, which forms part of the Beaufort Group in the Karoo Supergroup. The rocks within the study area are composed majorly of sandstone and mudstone. Lineaments were automatically extracted using the PCI Geomatica 2018 software. Fifteen samples were collected at various locations within the study area and were analyzed using the petrographic microscope while others were analyzed with the Scanning Electron Microscopic (SEM) combined with an Energy dispersive x-ray spectrometry. The results show that the rocks are fractured, porous and contained minerals such as quartz, feldspar, calcite, mica and clay minerals. The occurrence of these fractures helps to improve the groundwater storage capacity in the study area. Out of the twenty seven (27) rock samples collected in the field, ten (10) rock samples were selected for densities (dry, wet and grain densities) and porosity measurements in the laboratory. The rocks density values range from 2.5763 – 2.6978 g/cm3. The average porosities of the rocks range from 0.85 – 2.56 percent. The density of the sandstone ranges from 2.5908 – 2.6820 g/cm3 whilst the porosity range from 0.85 – 2.02 percent. The density of the mudstone ranges from 2.5763 – 2.6978 g/cm3 whilst the porosity ranges from 1.84 – 2.56 percent. About 8458 magnetic measurements were taken at about 20 m spacing along linear and non-linear paths and road. A variety of magnetic maps were generated. Several magnetic highs were observed and the linear highs were interpreted to be due to dolerite dykes whilst the broader high zones were inferred to be due to dolerite sills. These Karoo dolerites intruded the sediments at various depths and must have fractured the sediments causing them to be more porous and permeable. The depth slices of magnetic data reveal that near surface magnetic bodies occur within the depth of approximately 19 m from the surface while deep seated ones occur as deep as 31 m and maybe deeper. The knowledge of the dolerite intrusions enabled the location of drilling targets for groundwater. Electrical resistivity data were collected at 28 sites using the Schlumberger array and a maximum cable length (250 m) from the centre point which achieved a maximum depth penetration of about 70 m to 162 m. The results from 1D modelling using WINRESIST software showed that the vertical electric sounding curves are composed of HA and HK curve-types, which show four geoelectric layers. The resistivity of the first layer which is the topmost layer has values ranging from 20 - 5752 Ωm and the thickness is between 0.4 – 1.8 m. The second layer which consists of clay, mudstone and sandstone has resistivity values varying from 3 - 51 Ωm and thickness varying from 0.8 – 17.5 m. The third layer which is interpreted to be the aquiferous layer of the study area is made up majorly of sandstone with resistivity that varies from 136 – 352 Ωm and thickness range from 9.9 – 143.9 m. The fourth layer of resistivity varying from 44 to 60428 Ωm is made up of mudstone and sandstone, which are in some places intruded by dolerites. Groundwater potential is favourably high in some of the areas investigated. Furthermore, the results of the research indicated that secondary porosity is the main porosity for the reservoir rocks in the study area. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Pharmacological, toxicological and phytochemical evaluation of helichrysum petiolare hilliard & b.l. burtt - an indigenous plant traditionally used in the treatment of diabetes in the eastern cape province of South Africa
- Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Authors: Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Date: 2022-04
- Subjects: Diabetes -- Alternative treatment , Traditional medicine , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22787 , vital:52755
- Description: Diabetes mellitus is one of the leading causes of death in South Africa, and it has already placed significant stress on the country’s health sector and economy. The orthodox hypoglycaemic drugs are not only ineffective in the management of the disease and its complications, but they also possess unwanted side effects. The need for alternative non-toxic drugs is therefore imperative. Various studies have listed several medicinal plants that can be successfully used in the herbal treatment of diabetes and have investigated them for their anti-diabetic potentials in vivo and/or in vitro. Out of the different potential herbal species, plants belonging to the Asteraceae family possess highly potent hypoglycaemic properties with negligible toxicities. Five Asteraceae plants widely used in different parts of South Africa for the treatment of diabetes were reviewed. The review provided an update of scientific evidence on the hypoglycaemic properties of the plants. However, Helichrysum petiolare was studied extensively in this study for its antidiabetic activity H. petiolare has been listed in many ethnobotanical surveys as a plant with potent hypoglycaemic potential, this, however, has not been properly verified in scientific literature and there has hardly been any study on the essential oil and nutritional composition, and antioxidant, antidiabetic, and cytotoxicity potentials of the plant. The effects of hydro-distillation (HD) and solvent-free microwave extraction (SFME) methods on the chemical constituents of H. petiolare-derived essential oils were evaluated. The SFME method had a higher yield of essential oil than the HD. There were substantial amounts of monoterpenes, monoterpene alcohols, sesquiterpenes, and sesquiterpene alcohols in both essential oils obtained, but these compounds were more profound in the SFME derived essential oil which has 62 compounds compared to the 52 derived through HD. The SFME derived essential oil can therefore be said to be of better quality than the HD method. The compounds obtained in the essential oils have high pharmaceutical and cosmetic value, and as observed in this study, their quantity is dependent on the method of extraction (Ibáñez and Blázquez, 2021; Kaur et al., 2021). The proximate analysis of the whole plant of H. petiolare showed high levels of Acid Detergent Fibre (ADF), vitamins (A, C and E), Neutral Detergent Fibre (NDF), and minerals. The high ADF level is believed to be responsible for the low energy, fat and carbohydrate levels observed in the study. The result showed a high level of oxalate and therefore suggests cooking of the plant before human consumption. Overall nutrition and mineral compositions of the plant showed that H. petiolare is immensely rich in vital nutrients that are of great importance to health and metabolism; these nutrients are suggested to be partly responsible for the plant’s useful medicinal properties. The phytochemical contents of the acetone (ACQ), ethanol (ETQ), and boiled (BAQ) and cold (CAQ) aqueous whole-plant extracts of Helichrysum petiolare were determined using standard phytochemical reaction methods. ABTS, DPPH, NO and TAC assays were used to evaluate their antioxidant properties. The highest total phenolic content (212,963 mg/g) was reported in the BAQ extract, while the ETQ had the highest flavonoid (172.393 mg/g) and proanthocyanidin contents (65.855 mg/g). Alkaloids, flavonols, and saponin were highest in the ACQ extract, while the CAQ had the lowest phytochemical content. Among the extracts, the BAQ had the highest DPPH•+ (IC50 0.02 mg/mL) and ABTS•+ (IC50 0.07) inhibition capacities, while the ETQ exhibited the highest NO• Inhibition (IC50 0.41 mg/mL) and TAC (IC50 0.19 mg/mL). These findings justify the use of H. petiolare in traditional medicine and further recommend the ETQ and BAQ extracts of the plant as more effective extracts for medicinal treatment. The hepatotoxicity (cytotoxicity, mitotoxicity and lipotoxicity) potential of the BAQ, CAQ and ETQ extracts of Helichrysum petiolare was evaluated using standard procedures. The results showed negligible BAQ and CAQ cytotoxicities, which were further, corroborated by stability in the mitochondrial membrane potentials and were congruent with the CAQ and BAQ results for steatosis and phospholipidosis. The data suggested favourable CAQ and BAQ toxicity profiles with limited risks for hepatotoxicity. The ETQ extract, however, showed significantly high levels of cytotoxicity and lipotoxicity, and a low level of mitotoxicity. Our result suggested a potential risk of the ETQ extract for hepatotoxicity but appears partly independent of direct mitochondrial involvement. Glucose uptake assay showed significantly increased glucose uptake in the BAQ and CAQ treated L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase activities as compared to CAQ. The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus. This study provides up to date scientific information on the use of H. petiolare in the treatment of diabetes mellitus in the Eastern Cape of South Africa. It justifies the use of this plant in herbal medicine and sheds more light on its previously vaguely understood nutritional and medicinal potentials. More studies, however, need to be done to isolate, identify and purify the constituent bioactive compound(s). Their dosage of application and mode of action also needs to be understood. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Date: 2022-04
- Subjects: Diabetes -- Alternative treatment , Traditional medicine , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22787 , vital:52755
- Description: Diabetes mellitus is one of the leading causes of death in South Africa, and it has already placed significant stress on the country’s health sector and economy. The orthodox hypoglycaemic drugs are not only ineffective in the management of the disease and its complications, but they also possess unwanted side effects. The need for alternative non-toxic drugs is therefore imperative. Various studies have listed several medicinal plants that can be successfully used in the herbal treatment of diabetes and have investigated them for their anti-diabetic potentials in vivo and/or in vitro. Out of the different potential herbal species, plants belonging to the Asteraceae family possess highly potent hypoglycaemic properties with negligible toxicities. Five Asteraceae plants widely used in different parts of South Africa for the treatment of diabetes were reviewed. The review provided an update of scientific evidence on the hypoglycaemic properties of the plants. However, Helichrysum petiolare was studied extensively in this study for its antidiabetic activity H. petiolare has been listed in many ethnobotanical surveys as a plant with potent hypoglycaemic potential, this, however, has not been properly verified in scientific literature and there has hardly been any study on the essential oil and nutritional composition, and antioxidant, antidiabetic, and cytotoxicity potentials of the plant. The effects of hydro-distillation (HD) and solvent-free microwave extraction (SFME) methods on the chemical constituents of H. petiolare-derived essential oils were evaluated. The SFME method had a higher yield of essential oil than the HD. There were substantial amounts of monoterpenes, monoterpene alcohols, sesquiterpenes, and sesquiterpene alcohols in both essential oils obtained, but these compounds were more profound in the SFME derived essential oil which has 62 compounds compared to the 52 derived through HD. The SFME derived essential oil can therefore be said to be of better quality than the HD method. The compounds obtained in the essential oils have high pharmaceutical and cosmetic value, and as observed in this study, their quantity is dependent on the method of extraction (Ibáñez and Blázquez, 2021; Kaur et al., 2021). The proximate analysis of the whole plant of H. petiolare showed high levels of Acid Detergent Fibre (ADF), vitamins (A, C and E), Neutral Detergent Fibre (NDF), and minerals. The high ADF level is believed to be responsible for the low energy, fat and carbohydrate levels observed in the study. The result showed a high level of oxalate and therefore suggests cooking of the plant before human consumption. Overall nutrition and mineral compositions of the plant showed that H. petiolare is immensely rich in vital nutrients that are of great importance to health and metabolism; these nutrients are suggested to be partly responsible for the plant’s useful medicinal properties. The phytochemical contents of the acetone (ACQ), ethanol (ETQ), and boiled (BAQ) and cold (CAQ) aqueous whole-plant extracts of Helichrysum petiolare were determined using standard phytochemical reaction methods. ABTS, DPPH, NO and TAC assays were used to evaluate their antioxidant properties. The highest total phenolic content (212,963 mg/g) was reported in the BAQ extract, while the ETQ had the highest flavonoid (172.393 mg/g) and proanthocyanidin contents (65.855 mg/g). Alkaloids, flavonols, and saponin were highest in the ACQ extract, while the CAQ had the lowest phytochemical content. Among the extracts, the BAQ had the highest DPPH•+ (IC50 0.02 mg/mL) and ABTS•+ (IC50 0.07) inhibition capacities, while the ETQ exhibited the highest NO• Inhibition (IC50 0.41 mg/mL) and TAC (IC50 0.19 mg/mL). These findings justify the use of H. petiolare in traditional medicine and further recommend the ETQ and BAQ extracts of the plant as more effective extracts for medicinal treatment. The hepatotoxicity (cytotoxicity, mitotoxicity and lipotoxicity) potential of the BAQ, CAQ and ETQ extracts of Helichrysum petiolare was evaluated using standard procedures. The results showed negligible BAQ and CAQ cytotoxicities, which were further, corroborated by stability in the mitochondrial membrane potentials and were congruent with the CAQ and BAQ results for steatosis and phospholipidosis. The data suggested favourable CAQ and BAQ toxicity profiles with limited risks for hepatotoxicity. The ETQ extract, however, showed significantly high levels of cytotoxicity and lipotoxicity, and a low level of mitotoxicity. Our result suggested a potential risk of the ETQ extract for hepatotoxicity but appears partly independent of direct mitochondrial involvement. Glucose uptake assay showed significantly increased glucose uptake in the BAQ and CAQ treated L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase activities as compared to CAQ. The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus. This study provides up to date scientific information on the use of H. petiolare in the treatment of diabetes mellitus in the Eastern Cape of South Africa. It justifies the use of this plant in herbal medicine and sheds more light on its previously vaguely understood nutritional and medicinal potentials. More studies, however, need to be done to isolate, identify and purify the constituent bioactive compound(s). Their dosage of application and mode of action also needs to be understood. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
A mobile based control system for smart homes
- Authors: Tshimanga, Danny Kazadi
- Date: 2022-03
- Subjects: Smart power grids , Home automation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22632 , vital:52606
- Description: A Smart Home Control System can provide a secure home, convenience, comfort, and interactivity of life in a particular home. The system can enable the automatic controlling of a house via a Smart Phone. These systems are becoming vital and widely used in homes to improve conditions of life. Most commercial home automation systems are expensive and their maintenance would require experts who understand the underlying implementation of the systems. This study developed a mobile-based home automation system prototype. The system was developed using the waterfall model methodology. To evaluate the developed system, the study used a simulation method. Ten trials were conducted to determine the performance of the implemented system. The mean time to failure was used to evaluate the system’ reliability. The system’s performance analysis revealed that the developed system performed better than the two other approaches; the Bluetooth and ZigBee. The developed system showed a 0 percent error, while the Bluetooth had 8 percent error and ZigBee 6 percent error. The reliability results showed the average lifespan of assets in the system before they could fail. Knowing the lifespan of an asset before it fails can help in reducing downtime of the system by planning or scheduling maintenance and develop an improved maintenance strategy. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2022-03
- Authors: Tshimanga, Danny Kazadi
- Date: 2022-03
- Subjects: Smart power grids , Home automation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22632 , vital:52606
- Description: A Smart Home Control System can provide a secure home, convenience, comfort, and interactivity of life in a particular home. The system can enable the automatic controlling of a house via a Smart Phone. These systems are becoming vital and widely used in homes to improve conditions of life. Most commercial home automation systems are expensive and their maintenance would require experts who understand the underlying implementation of the systems. This study developed a mobile-based home automation system prototype. The system was developed using the waterfall model methodology. To evaluate the developed system, the study used a simulation method. Ten trials were conducted to determine the performance of the implemented system. The mean time to failure was used to evaluate the system’ reliability. The system’s performance analysis revealed that the developed system performed better than the two other approaches; the Bluetooth and ZigBee. The developed system showed a 0 percent error, while the Bluetooth had 8 percent error and ZigBee 6 percent error. The reliability results showed the average lifespan of assets in the system before they could fail. Knowing the lifespan of an asset before it fails can help in reducing downtime of the system by planning or scheduling maintenance and develop an improved maintenance strategy. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2022-03
Assessment of soil erosion based on clustered geoinformatics approaches: a case study of Tyume River Catchment, Eastern Cape, South Africa
- Mbatyoti, Siyanda https://orcid.org/0000-0002-9736-5684
- Authors: Mbatyoti, Siyanda https://orcid.org/0000-0002-9736-5684
- Date: 2022-03
- Subjects: Soil erosion , Geoinformatics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22852 , vital:52969
- Description: This research centres on the holistic assessments of spatial and temporal dimensions of soil erosion zones based on the parameters of geomorphometry, hydro-statistics, and land use/cover dynamics. The study used a case study approach based on a clustered framework model of soil erosion parameters in the Tyume River basin in Eastern Cape, South Africa. The methods adopted for the investigation are, namely; non-parametric time-series assessment of streamflow dataset, semidecadal assessment of land use/cover (LU/C) dynamics, geospatial analysis of geomorphometric variables, vulnerability analysis of soil erosion zones, regression analysis of determination coefficient, and Receiver Operating Characteristic Curve (ROC). The delineation of soil erosion zones was based on the integrated analysis of the parameters of geomorphometry, geology, hydrology, and land use/ cover. The result of the hydro-statistical analysis of the Tyume River reports a major decline in the inter-annual regime frequency of storm flow based on the Mann- Kendall (MK) test and Sen’s slope assessment in 1992 (p-value = 0.031), 1997 (p-value = 0.045), 2003 (p-value = 0.021), 2008 (p-value = 0.003), and 2016 (p-value = 0.002). The MK test depicted a recurrence of peak streamflow acceleration in every three years based on low-flow and highflow transition. The sensitivity of LU/C to temporal dynamics of streamflow trends shown by the coefficient of correlation of trends of the LU/C water bodies with streamflow semi-decadal acceleration indicates a moderately relevant relationship, R = 0.76. The temporal analysis of LU/C and hydro-statistical analysis shows that the Tyume basin was highly vulnerable to soil erosion by water in 1999, 2009, and 2019. The vulnerability of the Tyume River basin in 2019 is exceptional and this is due to the conversion of forested area (woodland) into a built-up environment and farmland, with a high vulnerability in 2019 due to the slump in the rate of change of woodland and precipitation, and the increase in the rate of built-up and agricultural activities. The soil erosion vulnerability mapping divides the river basin into the critical high, high, moderate, low, nonvulnerable zones that cover 40 km2, 135 km2, 209 km2, and 186 km2 respectively. Regression analysis shows that the areas of soil erosion in the Tyume basin are moderately represented by the model (R2 = 56) while the model performance assessment based on success rate and prediction rate estimation from the area under the ROC curve shows that the model is good, Area Under Curve of the ROC = 0.899, and 0.897. The analysis suggests that soil erosion is driven by the impact of land use/land cover change, particularly in areas of high drainage density. Significantly, high vegetation density played a vital role in lowering high-flow on the hill-slope and low topographic wetness area as well as in areas with erodible geologic properties. The study, therefore, recommends the advocacy of crop rotation method of agricultural practice in the highly critical areas of soil erosion and recommends the development of riparian forests around the Tyume River. The study provides important information for environmental stakeholders on degradable areas which may require the urgent implementation of sustainable development measures. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Mbatyoti, Siyanda https://orcid.org/0000-0002-9736-5684
- Date: 2022-03
- Subjects: Soil erosion , Geoinformatics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22852 , vital:52969
- Description: This research centres on the holistic assessments of spatial and temporal dimensions of soil erosion zones based on the parameters of geomorphometry, hydro-statistics, and land use/cover dynamics. The study used a case study approach based on a clustered framework model of soil erosion parameters in the Tyume River basin in Eastern Cape, South Africa. The methods adopted for the investigation are, namely; non-parametric time-series assessment of streamflow dataset, semidecadal assessment of land use/cover (LU/C) dynamics, geospatial analysis of geomorphometric variables, vulnerability analysis of soil erosion zones, regression analysis of determination coefficient, and Receiver Operating Characteristic Curve (ROC). The delineation of soil erosion zones was based on the integrated analysis of the parameters of geomorphometry, geology, hydrology, and land use/ cover. The result of the hydro-statistical analysis of the Tyume River reports a major decline in the inter-annual regime frequency of storm flow based on the Mann- Kendall (MK) test and Sen’s slope assessment in 1992 (p-value = 0.031), 1997 (p-value = 0.045), 2003 (p-value = 0.021), 2008 (p-value = 0.003), and 2016 (p-value = 0.002). The MK test depicted a recurrence of peak streamflow acceleration in every three years based on low-flow and highflow transition. The sensitivity of LU/C to temporal dynamics of streamflow trends shown by the coefficient of correlation of trends of the LU/C water bodies with streamflow semi-decadal acceleration indicates a moderately relevant relationship, R = 0.76. The temporal analysis of LU/C and hydro-statistical analysis shows that the Tyume basin was highly vulnerable to soil erosion by water in 1999, 2009, and 2019. The vulnerability of the Tyume River basin in 2019 is exceptional and this is due to the conversion of forested area (woodland) into a built-up environment and farmland, with a high vulnerability in 2019 due to the slump in the rate of change of woodland and precipitation, and the increase in the rate of built-up and agricultural activities. The soil erosion vulnerability mapping divides the river basin into the critical high, high, moderate, low, nonvulnerable zones that cover 40 km2, 135 km2, 209 km2, and 186 km2 respectively. Regression analysis shows that the areas of soil erosion in the Tyume basin are moderately represented by the model (R2 = 56) while the model performance assessment based on success rate and prediction rate estimation from the area under the ROC curve shows that the model is good, Area Under Curve of the ROC = 0.899, and 0.897. The analysis suggests that soil erosion is driven by the impact of land use/land cover change, particularly in areas of high drainage density. Significantly, high vegetation density played a vital role in lowering high-flow on the hill-slope and low topographic wetness area as well as in areas with erodible geologic properties. The study, therefore, recommends the advocacy of crop rotation method of agricultural practice in the highly critical areas of soil erosion and recommends the development of riparian forests around the Tyume River. The study provides important information for environmental stakeholders on degradable areas which may require the urgent implementation of sustainable development measures. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
Effects of climatic variability on maize productivity in South Africa from 1937-2018
- Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Authors: Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Date: 2022-03
- Subjects: Crops and climate , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21410 , vital:48576
- Description: Climate is an important factor in agricultural production. The world is facing climate change and variability, which result in high temperatures, low rainfall patterns, shortage of water and persistent droughts. Climate change poses a significant threat to South Africa’s water resources, food security, health, infrastructure, ecosystem services and biodiversity. Negative impacts of climate variability on agriculture, especially on maize the staple crop, will worsen the food security status of the nation as most of South Africa’s maize crop is produced in summer and highly depends on rainfall. This study attempted to assess the impact of climate on maize production in South Africa using secondary time series data for the period 1937 to 2018. Rainfall and temperature were used as proxies for climate variability. The Granger Causality Model was used to examine the causal linkages between climatic variables (temperature or rainfall) and maize output in South Africa for the study period. The major outcome of the analysis was that there is a two-way causal relationship between maize production and temperature. The results also indicated that there is uni-directional causality between maize yield and rainfall. Furthermore, the Variance Decomposition Model was used to forecast the relationship between climatic elements and maize production in South Africa. The result showed that all variables have an effect on maize yield, with temperature having the least effect. The last objective of the study was to profile the maize output trend for the period from 1937 to 2018. The main findings from the analysis indicate that maize production in South Africa has a general upward slope. The study recommends that the government should intensify the provision of irrigation systems for the farmers in the most vulnerable areas to mitigate the climate change. Government should also embark on massive campaigns using a variety of media to create the needed public awareness on climate change and its impact on food security. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Awum Awum, Rudin https://orcid.org/ 0000-0002-8740-6163
- Date: 2022-03
- Subjects: Crops and climate , Climatic changes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21410 , vital:48576
- Description: Climate is an important factor in agricultural production. The world is facing climate change and variability, which result in high temperatures, low rainfall patterns, shortage of water and persistent droughts. Climate change poses a significant threat to South Africa’s water resources, food security, health, infrastructure, ecosystem services and biodiversity. Negative impacts of climate variability on agriculture, especially on maize the staple crop, will worsen the food security status of the nation as most of South Africa’s maize crop is produced in summer and highly depends on rainfall. This study attempted to assess the impact of climate on maize production in South Africa using secondary time series data for the period 1937 to 2018. Rainfall and temperature were used as proxies for climate variability. The Granger Causality Model was used to examine the causal linkages between climatic variables (temperature or rainfall) and maize output in South Africa for the study period. The major outcome of the analysis was that there is a two-way causal relationship between maize production and temperature. The results also indicated that there is uni-directional causality between maize yield and rainfall. Furthermore, the Variance Decomposition Model was used to forecast the relationship between climatic elements and maize production in South Africa. The result showed that all variables have an effect on maize yield, with temperature having the least effect. The last objective of the study was to profile the maize output trend for the period from 1937 to 2018. The main findings from the analysis indicate that maize production in South Africa has a general upward slope. The study recommends that the government should intensify the provision of irrigation systems for the farmers in the most vulnerable areas to mitigate the climate change. Government should also embark on massive campaigns using a variety of media to create the needed public awareness on climate change and its impact on food security. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
Organophosphate flame retardant’s signatures in the Buffalo River Estuary and their removal using modified cyclodextrins
- Authors: Bika, Sinozuko Hope
- Date: 2022-03
- Subjects: Water purification chemicals industry , Organic water pollutants , Rivers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27500 , vital:67363
- Description: The increasing scarcity of fresh and clean water in many places around the world is a major concern. Water is a basic need that must be availed to humans, plants and animals at any given time. It is a requirement that each human on earth should get between 20-50 L of fresh, clean and pure water a day. It is very difficult to keep up with this need due to drastic increase in global pollution by emerging contaminants. The increase is due to human activities, modern way of life, industrialization and improper disposal of materials that contain these OPFRs. Organophosphate flame retardants OPFRs are the organic pollutants considered in this study. OPFRs are semi volatile compounds SVOCs that are used in many industries as flame retardants and additives. They were developed because of environmental and health concerns of previously used brominated and chlorinated flame retardants FRs. They show acute toxicity and exhibit adverse effects such as neurotoxicity, they are also carcinogenic to humans and animals. In recent years, some researchers have started investigating the occurrence and distribution of OPFRs in South African rivers. The aim of this study was to identify signatures of OPFRs in the aquatic environment of Buffalo River Estuary, and soil from a nearby dumpsite: and to develop a method for their removal using modified cyclodextrins. In this study, the concentration of OPFRs were investigated in sediments and soil samples collected from Buffalo River Estuary. This estuary is located close to a major port in East London city in the Eastern Cape Province, South Africa. Collection of samples was done across two seasons i.e. winter and spring. OPFRs in sediment and soil samples in this study were extracted using ultrasonic extraction method. Solid-phase extraction SPE was employed for the cleanup of the extracts, in order to reduce potential matrix interference and also for sample purification. The congeners of interest in this study were Tris 2-Choroethyl phosphate TCEP and Tris 1,3-Dicloro-2-propyl phosphate (TDCP). Samples were air dried immediately on arrival at the laboratory after being stored in an ice chest at 4 ℃ and further processed for further analysis.The concentrations of OPFRs were determined using GC-μECD (gas chromatograph coupled with micro electron capture detector) from soil and sediments in that area and they were found high in winter compared to spring owing to high level of discharge of industrial and domestic waste into the aquatic system and also the nearby dumpsite. The total concentrationof OPFRs Ʃ 2OPFRs for sediments and soil for both seasons was 39935±7619 μg/g and 10376±601 μg/g, respectively. The dominant congener in the Buffalo River Estuary was TCEP. The ecological risk assessment was estimated for the study area, and TCEP moderate risk while TDCP presented low risk. From this study, it could be inferred that the Buffalo River Estuary and the nearby dumpsite in East London are polluted by emerging pollutants i.e. OPFRs. Hence, strict control measures should be put in place to monitor all activities contributing to such magnitude of pollution in the estuary, which is of great economic value to the country. Furthermore in this study, an insoluble and hydrophilic polymer EDTA-Cysteine-β-Cyclodextrin was prepared and synthesized for the remediation of OPFRs in soil and sediments. This newly developed method was tested for the removal of TDCP an OPFR congener and it was successful with an average removal rate of 77.49 percent. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Bika, Sinozuko Hope
- Date: 2022-03
- Subjects: Water purification chemicals industry , Organic water pollutants , Rivers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27500 , vital:67363
- Description: The increasing scarcity of fresh and clean water in many places around the world is a major concern. Water is a basic need that must be availed to humans, plants and animals at any given time. It is a requirement that each human on earth should get between 20-50 L of fresh, clean and pure water a day. It is very difficult to keep up with this need due to drastic increase in global pollution by emerging contaminants. The increase is due to human activities, modern way of life, industrialization and improper disposal of materials that contain these OPFRs. Organophosphate flame retardants OPFRs are the organic pollutants considered in this study. OPFRs are semi volatile compounds SVOCs that are used in many industries as flame retardants and additives. They were developed because of environmental and health concerns of previously used brominated and chlorinated flame retardants FRs. They show acute toxicity and exhibit adverse effects such as neurotoxicity, they are also carcinogenic to humans and animals. In recent years, some researchers have started investigating the occurrence and distribution of OPFRs in South African rivers. The aim of this study was to identify signatures of OPFRs in the aquatic environment of Buffalo River Estuary, and soil from a nearby dumpsite: and to develop a method for their removal using modified cyclodextrins. In this study, the concentration of OPFRs were investigated in sediments and soil samples collected from Buffalo River Estuary. This estuary is located close to a major port in East London city in the Eastern Cape Province, South Africa. Collection of samples was done across two seasons i.e. winter and spring. OPFRs in sediment and soil samples in this study were extracted using ultrasonic extraction method. Solid-phase extraction SPE was employed for the cleanup of the extracts, in order to reduce potential matrix interference and also for sample purification. The congeners of interest in this study were Tris 2-Choroethyl phosphate TCEP and Tris 1,3-Dicloro-2-propyl phosphate (TDCP). Samples were air dried immediately on arrival at the laboratory after being stored in an ice chest at 4 ℃ and further processed for further analysis.The concentrations of OPFRs were determined using GC-μECD (gas chromatograph coupled with micro electron capture detector) from soil and sediments in that area and they were found high in winter compared to spring owing to high level of discharge of industrial and domestic waste into the aquatic system and also the nearby dumpsite. The total concentrationof OPFRs Ʃ 2OPFRs for sediments and soil for both seasons was 39935±7619 μg/g and 10376±601 μg/g, respectively. The dominant congener in the Buffalo River Estuary was TCEP. The ecological risk assessment was estimated for the study area, and TCEP moderate risk while TDCP presented low risk. From this study, it could be inferred that the Buffalo River Estuary and the nearby dumpsite in East London are polluted by emerging pollutants i.e. OPFRs. Hence, strict control measures should be put in place to monitor all activities contributing to such magnitude of pollution in the estuary, which is of great economic value to the country. Furthermore in this study, an insoluble and hydrophilic polymer EDTA-Cysteine-β-Cyclodextrin was prepared and synthesized for the remediation of OPFRs in soil and sediments. This newly developed method was tested for the removal of TDCP an OPFR congener and it was successful with an average removal rate of 77.49 percent. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
Perceptions and determinants of genetically modified (GM) maize production among rural households: The case of Ngqushwa Local Municipality, South Africa
- Zamisa, Owethu https://orcid.org/0000-0002-7303-4469
- Authors: Zamisa, Owethu https://orcid.org/0000-0002-7303-4469
- Date: 2022-03
- Subjects: Genetically modified foods , Agricultural biotechnology , Sustainable agriculture -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22479 , vital:52343
- Description: Rural South Africa is faced with immense challenges including poverty, unemployment, low agriculture productivity, food and nutritional insecurity and inequalities. Against this background, enhancing rural agricultural productivity using proven technologies such as genetically modified (GM) maize production is suggested as a pathway to economic development and poverty reduction. Literature suggests that GM technology can increase crop yields, drought tolerance, reduced weeding labour costs and chemical spray costs. However, GM maize varieties available on the market currently were created to fit large-scale, capital-intensive, industrialised, and economically oriented agricultural systems. As a result, their uptake has been significantly slow especially in rural areas where several stakeholders are now questioning the potential of GM technology. With that background, this study aimed to understand determinants of gm maize production among rural farming households and their perceptions using the case of Ngqushwa Local Municipality. Specifically, the study sought to analyse types of maize varieties grown by rural households, associated yields, area allocation, rural households’ perceptions of GM maize, and to estimate factors that influence GM maize awareness, participation and intensity of production among this subsector. Using a cross-sectional survey research design, a sample size of 400 households was randomly selected and interviewed using a semi-structured questionnaire. The types of maize varieties grown by rural households, associated yields, area allocation and rural households’ perceptions of GM maize were analysed using descriptive statistics. Factors that influence GM maize awareness, participation, and intensity of production were estimated using a triple hurdle model where the 1st and 2nd hurdle were estimated using Probit regression, and 3rd hurdle a Tobit regression. The study revealed that landrace maize varieties are currently the most popular maize varieties grown by the majority of rural farming households from the study area producing higher yields (0.6t/ha) as compared to other hybrids (GM – 0.5t/ha, conventional hybrids -0.3t/ha and improved OPVs – 0.1t/ha). Descriptive statistics results also indicated that farming households from the study area allocated more land to landrace maize varieties (42percent) compared to other maize varieties (GM maize (30percent), hybrids (21percent) and improved OPVs (7percent) further supporting the notion that landrace maize varieties dominate the rural farming subsector. Perception results revealed that the majority (57percent) of the households perceived GM maize as an expensive variety which, however, has a potential to produce relatively higher yields than other hybrids on the market and eliminates several production problems (manual weeding, pest spraying) making farm management easier. Findings further indicate that the majority (52percent) of the farming households from the study area did not have sufficient knowledge of GM maize. Econometrics results revealed that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Conditional on awareness of GM maize varieties, both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, size of arable land and negatively influenced by employment status and income. Against this background, the study concludes that farming households from the study area produced more compared to the other varieties. Furthermore, the study concludes that households get higher yields from landrace maize varieties and allocate more of their land to landrace maize production. In addition, the study also concludes that most rural farmers perceive participation in GM maize as beneficial especially towards elimination of farm management problems, produces higher yields, and makes farm management easier. Lastly, the study concludes that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, arable land and negatively influenced by employment status and income. The study recommends that priority should be given to these socio-economic and institutional factors and this may be addressed by targeting GM maize awareness campaigns and platforms more suited to female-headed, older, lowly educated and unemployed rural farming households. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Zamisa, Owethu https://orcid.org/0000-0002-7303-4469
- Date: 2022-03
- Subjects: Genetically modified foods , Agricultural biotechnology , Sustainable agriculture -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22479 , vital:52343
- Description: Rural South Africa is faced with immense challenges including poverty, unemployment, low agriculture productivity, food and nutritional insecurity and inequalities. Against this background, enhancing rural agricultural productivity using proven technologies such as genetically modified (GM) maize production is suggested as a pathway to economic development and poverty reduction. Literature suggests that GM technology can increase crop yields, drought tolerance, reduced weeding labour costs and chemical spray costs. However, GM maize varieties available on the market currently were created to fit large-scale, capital-intensive, industrialised, and economically oriented agricultural systems. As a result, their uptake has been significantly slow especially in rural areas where several stakeholders are now questioning the potential of GM technology. With that background, this study aimed to understand determinants of gm maize production among rural farming households and their perceptions using the case of Ngqushwa Local Municipality. Specifically, the study sought to analyse types of maize varieties grown by rural households, associated yields, area allocation, rural households’ perceptions of GM maize, and to estimate factors that influence GM maize awareness, participation and intensity of production among this subsector. Using a cross-sectional survey research design, a sample size of 400 households was randomly selected and interviewed using a semi-structured questionnaire. The types of maize varieties grown by rural households, associated yields, area allocation and rural households’ perceptions of GM maize were analysed using descriptive statistics. Factors that influence GM maize awareness, participation, and intensity of production were estimated using a triple hurdle model where the 1st and 2nd hurdle were estimated using Probit regression, and 3rd hurdle a Tobit regression. The study revealed that landrace maize varieties are currently the most popular maize varieties grown by the majority of rural farming households from the study area producing higher yields (0.6t/ha) as compared to other hybrids (GM – 0.5t/ha, conventional hybrids -0.3t/ha and improved OPVs – 0.1t/ha). Descriptive statistics results also indicated that farming households from the study area allocated more land to landrace maize varieties (42percent) compared to other maize varieties (GM maize (30percent), hybrids (21percent) and improved OPVs (7percent) further supporting the notion that landrace maize varieties dominate the rural farming subsector. Perception results revealed that the majority (57percent) of the households perceived GM maize as an expensive variety which, however, has a potential to produce relatively higher yields than other hybrids on the market and eliminates several production problems (manual weeding, pest spraying) making farm management easier. Findings further indicate that the majority (52percent) of the farming households from the study area did not have sufficient knowledge of GM maize. Econometrics results revealed that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Conditional on awareness of GM maize varieties, both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, size of arable land and negatively influenced by employment status and income. Against this background, the study concludes that farming households from the study area produced more compared to the other varieties. Furthermore, the study concludes that households get higher yields from landrace maize varieties and allocate more of their land to landrace maize production. In addition, the study also concludes that most rural farmers perceive participation in GM maize as beneficial especially towards elimination of farm management problems, produces higher yields, and makes farm management easier. Lastly, the study concludes that GM maize awareness is negatively influenced by age and gender and positively influenced by marital status, employment status and number of years in school. Both participation and intensity of participation in GM maize production are positively influenced by land size, gender, group membership, arable land and negatively influenced by employment status and income. The study recommends that priority should be given to these socio-economic and institutional factors and this may be addressed by targeting GM maize awareness campaigns and platforms more suited to female-headed, older, lowly educated and unemployed rural farming households. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
Synthesis and evaluation of pyrene grafted onto zinc oxide nanoparticles for the removal of organic contaminants from wastewater
- Authors: Samuel, Zipho
- Date: 2022-03
- Subjects: Land treatment of wastewater , Zinc oxide , Water pollution control industry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27754 , vital:69407
- Description: Drinking water scarcity is a global crisis even though water covers about three quarters of the earth. One of the major causes of this scarcity is water pollution, which is a result of human activities. This has been noticed and reported for a number of years but is still unsolved and intensifying. Hence, scientists are busy trying to find solutions to this global menace. In this study, zinc oxide nanoparticles were synthesised via co-precipitation, a cost reasonable method and functionalized by grafting a pyrene ligand on its surface in order to provide a scaffold to which many other functionalities can be adsorbed. By so doing, the efficiency and capacity of bare nanoparticles is improved. The synthesised pyrene ligand was successfully characterised with nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscope (FTIR). The adsorbent was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), FTIR, energy dispersive x-ray (EDX) and thermogravimetric analyzer (TGA). The choice of zinc oxide nanoparticles as preferred adsorbent was due to their exceptional properties including large surface area, thermal and chemical stabilities. These properties are the reason zinc oxide nanoparticles possess high adsorption efficiency and capacity. The results of characterization indicated a decreased particle size and improved thermal stabilities of the pyrene grafted zinc oxide nanoparticles compared to the zinc oxide nanoparticles, showing that this material can be employed even at higher temperatures. The average particle size of the bare nanoparticles decreased from 290 to 181 nm after functionalization. Thermal stability increased from 550oC in the bare nanoparticles to 650oC in the functionalized nanoparticles. Characteristic reflections of zinc oxide nanoparticles in the XRD analysis were maintained even after functionalization However, diffractogram roughness was noticed for the functionalized nanoparticles due to the introduction of the amorphous layer from the ligand. This novel material was employed for the removal of an herbicide, simazine as well as two dyes, methyl violet and brilliant green from aqueous solutions by batch adsorption experiments. The kinetics and isotherm studies of the different adsorption processes were carried out by using three of the commonly used kinetic and isotherm models (pseudo-first order, intraparticle diffusion and pseudo-second order) and (Langmuir, Temkin isotherms and Freundlich) respectively. From all batch adsorption experiments conducted for simazine removal, the adsorbent showed effectiveness and high adsorption capacity for the removal of simazine. The highest observed efficiency and capacity were 71.3 percent and 137 mg/g respectively at pH equals 2, time equals 60 minutes, adsorbent dose equals 20 mg and adsorbate conc equals 0. 281 mg/L. Kinetics study for the adsorption of simazine favoured pseudo-first order. However, Langmuir isotherm could also be applicable to understand the adsorption process. The material also showed reusability potential of up to three cycles for this contaminant indicating that this material can be re-used. In the case of the removal of methyl violet from aqueous solution, the adsorbent showed a reasonable adsorption maximum capacity (qmax) (31.5 mg/g) at contact time equals 360 min, adsorbent dose approximately equals 40 mg, temperature equals 20 plus 2oC and pH equals 6.5, when compared to other adsorbents previously reported for the removal of methyl violet (MV) in literature. Kinetics and isotherm studies indicated that the process for the removal of this pollutant with this pyrene grafted onto zinc oxide nanoparticles proceeded via pseudo-first order (R2 equals 0.931) and Langmuir isotherm models (R2 equals 0.980) respectively. These results indicated that this material could serve as alternate material to already established materials for the removal of recalcitrant organic pollutants from aqueous solutions. Moreover, the adsorbent also showed reusability potential for this contaminant. Similarly, the adsorbent showed high removal efficiency and capacity in all batch adsorption experiments for brilliant green (BG) adsorption. The highest adsorption efficiency of 88.8 percent was accomplished with 79.8 mg at pH 6.50 and temperature of 20 equals 2oC within 360 minutes. BG adsorption rate mechanism was best explained by the pseudo-first order kinetic model (R2 equals 0.903). Dye adsorption behaviour was best explained using Langmuir isotherm (R2 equals 0.980). Reusability of the adsorbent showed that the adsorbent is efficient after three runs. The overall results of adsorption by a way of comparison of the adsorption capacity of this novel material with respect to the contaminants is in this trend: brilliant green greater methyl violet greater simazine. This study indicates that this novel material can serve as new material for the removal of herbicides and dyes as well as vast variety of pollutants from wastewater considering its high adsorption efficiency and its recyclability. Thus, industries can explore the use of this material for the removal of varying pollutants from wastewater. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Samuel, Zipho
- Date: 2022-03
- Subjects: Land treatment of wastewater , Zinc oxide , Water pollution control industry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27754 , vital:69407
- Description: Drinking water scarcity is a global crisis even though water covers about three quarters of the earth. One of the major causes of this scarcity is water pollution, which is a result of human activities. This has been noticed and reported for a number of years but is still unsolved and intensifying. Hence, scientists are busy trying to find solutions to this global menace. In this study, zinc oxide nanoparticles were synthesised via co-precipitation, a cost reasonable method and functionalized by grafting a pyrene ligand on its surface in order to provide a scaffold to which many other functionalities can be adsorbed. By so doing, the efficiency and capacity of bare nanoparticles is improved. The synthesised pyrene ligand was successfully characterised with nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscope (FTIR). The adsorbent was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), FTIR, energy dispersive x-ray (EDX) and thermogravimetric analyzer (TGA). The choice of zinc oxide nanoparticles as preferred adsorbent was due to their exceptional properties including large surface area, thermal and chemical stabilities. These properties are the reason zinc oxide nanoparticles possess high adsorption efficiency and capacity. The results of characterization indicated a decreased particle size and improved thermal stabilities of the pyrene grafted zinc oxide nanoparticles compared to the zinc oxide nanoparticles, showing that this material can be employed even at higher temperatures. The average particle size of the bare nanoparticles decreased from 290 to 181 nm after functionalization. Thermal stability increased from 550oC in the bare nanoparticles to 650oC in the functionalized nanoparticles. Characteristic reflections of zinc oxide nanoparticles in the XRD analysis were maintained even after functionalization However, diffractogram roughness was noticed for the functionalized nanoparticles due to the introduction of the amorphous layer from the ligand. This novel material was employed for the removal of an herbicide, simazine as well as two dyes, methyl violet and brilliant green from aqueous solutions by batch adsorption experiments. The kinetics and isotherm studies of the different adsorption processes were carried out by using three of the commonly used kinetic and isotherm models (pseudo-first order, intraparticle diffusion and pseudo-second order) and (Langmuir, Temkin isotherms and Freundlich) respectively. From all batch adsorption experiments conducted for simazine removal, the adsorbent showed effectiveness and high adsorption capacity for the removal of simazine. The highest observed efficiency and capacity were 71.3 percent and 137 mg/g respectively at pH equals 2, time equals 60 minutes, adsorbent dose equals 20 mg and adsorbate conc equals 0. 281 mg/L. Kinetics study for the adsorption of simazine favoured pseudo-first order. However, Langmuir isotherm could also be applicable to understand the adsorption process. The material also showed reusability potential of up to three cycles for this contaminant indicating that this material can be re-used. In the case of the removal of methyl violet from aqueous solution, the adsorbent showed a reasonable adsorption maximum capacity (qmax) (31.5 mg/g) at contact time equals 360 min, adsorbent dose approximately equals 40 mg, temperature equals 20 plus 2oC and pH equals 6.5, when compared to other adsorbents previously reported for the removal of methyl violet (MV) in literature. Kinetics and isotherm studies indicated that the process for the removal of this pollutant with this pyrene grafted onto zinc oxide nanoparticles proceeded via pseudo-first order (R2 equals 0.931) and Langmuir isotherm models (R2 equals 0.980) respectively. These results indicated that this material could serve as alternate material to already established materials for the removal of recalcitrant organic pollutants from aqueous solutions. Moreover, the adsorbent also showed reusability potential for this contaminant. Similarly, the adsorbent showed high removal efficiency and capacity in all batch adsorption experiments for brilliant green (BG) adsorption. The highest adsorption efficiency of 88.8 percent was accomplished with 79.8 mg at pH 6.50 and temperature of 20 equals 2oC within 360 minutes. BG adsorption rate mechanism was best explained by the pseudo-first order kinetic model (R2 equals 0.903). Dye adsorption behaviour was best explained using Langmuir isotherm (R2 equals 0.980). Reusability of the adsorbent showed that the adsorbent is efficient after three runs. The overall results of adsorption by a way of comparison of the adsorption capacity of this novel material with respect to the contaminants is in this trend: brilliant green greater methyl violet greater simazine. This study indicates that this novel material can serve as new material for the removal of herbicides and dyes as well as vast variety of pollutants from wastewater considering its high adsorption efficiency and its recyclability. Thus, industries can explore the use of this material for the removal of varying pollutants from wastewater. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
Threatened plant species in Vhembe Biosphere Reserve, Limpopo province, South Africa: Problems and prospects of conservation and utilization
- Ramarumo, Luambo Jeffrey https://orcid.org/0000-0002-2393-6982
- Authors: Ramarumo, Luambo Jeffrey https://orcid.org/0000-0002-2393-6982
- Date: 2022-03
- Subjects: Plants -- Extinction , Rare plants , Botany, Economic
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22754 , vital:52738
- Description: Threatened plant species are those species that are vulnerable or at the risk of extinction. According to Version 3.1 of the International Union for Conservation of Nature (IUCN)’s Red List Categories and Criteria, the three categories of threat in order of increasing risk of extinction are: Vulnerable (VU), Endangered (EN) and Critically Endangered (CR). These species are oftenly protected by both national and international obligations. Scientific evidence suggests that threatened plants are disappearing at an alarming rate. The current expansion of agricultural land, urbanization, over-exploitation of biological resources, climate change and invasive alien species are regarded as major drivers of biodiversity loss and high rate of species extinction worldwide. Scientists and conservation managers are seeking to understand and monitor plant species that are likely to be on the verge of extinction. Monitoring of threatened plants can be better achieved through insights about indigenous knowledge dynamics associated with such species. Scientific scholars including botanists, ethnobotanists, conservationists and anthropologists, all share common interest about the use of indigenous knowledge for livelihoods, scientific and economic growth. As a result, there is a growing interest on indigenous knowledge researches, particularly involving utilization and conservation of plant species. Given the fact that recent scientific evidence suggests that such studies are lacking in South African Biosphere Reserves, as well as the fact that scientist and conservation managers are seeking to understand species likely to be on the verge of extinction risk. It is within this context that this study is aimed at investigating threatened plant species utilization, conservation statuses and distribution in the Vhembe Biosphere Reserve, Limpopo Province in South Africa. The hypothesis of this study states that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices. Since the current study is ethnobotanical in nature that is focusing on human interactions with plants, the research methods used addressed multidisciplinary aspects and involved disciplinary integration. An integrated participatory research approach focusing on shared learning, forging collaborative relations with participants, analyzing and validating the shared knowledge was used to document ethnobotanical data within the study area. This research approach was selected as it is considered to be a quick and effective way of acquiring data associated with indigenous knowledge systems. To offset the elements of bias during data collection, the research technique was designed to accommodate core principles that interlinked participatory rural appraisal (PRA) and rapid rural appraisal (RRA). Furthermore, the integrated core principles of participatory rural appraisal and rapid rural appraisal were used with conventional methods such as field surveys and interviews using questionnaires. Therefore, ethnobotanical data were collected through interviews with 203 participants. The data associated with threatened plant’s population size were gathered through literal counting of individual plants as per the IUCN’s Red List Criteria. Data associated with the conservation statuses were gathered from both the South African National Biodiversity Institute and IUCN databases. A total of 13 useful threatened plants belonging to 12 families were recorded with their conservation statuses ranging from being Vulnerable to Critically Endangered. The majority of the threatened plant species (46.0percent) were used for medicinal purposes only, followed by species used for medicinal purposes and as ornamentals (23.0percent). The frequently cited useful threatened species with use values (UV) > 0.024, relative frequency citation (RFC) > 0.059 and fidelity level percentage (FLpercent) > 5.911percent, included Asparagus sekukuniensis, Bowiea volubilis, Brackenridgea zanguebarica, Ocotea bullata, Rhynchosia vendae, Siphonochilus aethiopicus and Warburgia salutaris. About 47.0percent of the recorded useful threatened plants were distributed in remote areas of the Thathe Vonḓo and its surroundings. Threatened plants with population size < 100 adult individuals constituted the majority (61.54percent). Birdlime-making plant species were also documented in the current study. A total of 12 birdlime-making plants belonging to six families were recorded, including threatened Huernia nouhuysii, which is categorized as Vulnerable in South Africa. Amongst the recorded families, Loranthaceae and Euphorbiaceae were categorized as the most frequently utilized families. Among the recorded species, six of them were reported to being used in the birdlime-making for the first time and these species include Euphorbia pulvinata (17.2percent), followed by Tapinanthus forbesii (8percent), Tapinanthus rubromarginatus (7.2percent), Erianthemum ngamicum (7.2percent), Englerophytum magalismon-tanum (3.6percent), Huernia nouhuysii (2.0percent), and Euphorbia tirucalli (0.8percent). Only three plant parts were utilized for birdlime-making. The milky latex was preferred plant part (58.3percent), followed by fruit (33.3percent) and root bark (8.4percent). Birdlime-making techniques involved crushing, which accounted for 55.7percent, followed by air blown (29.6percent) and boiling (14.7percent). Furthermore, the complementary contribution of birdlime toward human development included, being used for bird hunting or trapping small birds (45.8percent), adhesion (23.2percent), teeth cleaning (17.2percent) and roof-waterproofing (13.8percent). The indigenous conservation strategies employed by participants included harvesting of single lateral root per individual medicinal plant (15.3percent), medicinal and timber materials are only harvested during winter season (16.7percent), the use of moist soil to cover injured plant part after bark harvest (18.2percent), prohibit harvesting of and/ or from an injured plant (11.8percent), collection of dried or fallen plants for firewood (8.4percent), issuing of permits by traditional council through the chief or headman to allow collection of medicinal materials and timber (9.9percent), prohibit chopping down of medicinal plant species (13.8percent) and collection of some Critically Endangered plant species such as Brackenridgea zanguebarica and Siphonochilus aethiopicus during the night by authorized people only (5.9percent). The hypothesis which stated that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices can therefore, not be rejected as there is room for further and more detailed ethnobotanical investigations that is focused on human interactions with threatened plant species. The data presented in this thesis could be used as baseline information for formulating new conservation strategies, monitoring and management plans of threatened plant species not only in the Vhembe Biosphere Reserve, but in other regions of South African. This study provided insights associated with ethnomedicinal uses of Asparagus sekukuniensis, Protea laetans and Encephalartos hirsutus. Results of this study could also stimulate interest in other scientific disciplines such as the phytochemistry, pharmacology, bioprocessing, conservation and anthropology involving documentation threatened plant species. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Ramarumo, Luambo Jeffrey https://orcid.org/0000-0002-2393-6982
- Date: 2022-03
- Subjects: Plants -- Extinction , Rare plants , Botany, Economic
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22754 , vital:52738
- Description: Threatened plant species are those species that are vulnerable or at the risk of extinction. According to Version 3.1 of the International Union for Conservation of Nature (IUCN)’s Red List Categories and Criteria, the three categories of threat in order of increasing risk of extinction are: Vulnerable (VU), Endangered (EN) and Critically Endangered (CR). These species are oftenly protected by both national and international obligations. Scientific evidence suggests that threatened plants are disappearing at an alarming rate. The current expansion of agricultural land, urbanization, over-exploitation of biological resources, climate change and invasive alien species are regarded as major drivers of biodiversity loss and high rate of species extinction worldwide. Scientists and conservation managers are seeking to understand and monitor plant species that are likely to be on the verge of extinction. Monitoring of threatened plants can be better achieved through insights about indigenous knowledge dynamics associated with such species. Scientific scholars including botanists, ethnobotanists, conservationists and anthropologists, all share common interest about the use of indigenous knowledge for livelihoods, scientific and economic growth. As a result, there is a growing interest on indigenous knowledge researches, particularly involving utilization and conservation of plant species. Given the fact that recent scientific evidence suggests that such studies are lacking in South African Biosphere Reserves, as well as the fact that scientist and conservation managers are seeking to understand species likely to be on the verge of extinction risk. It is within this context that this study is aimed at investigating threatened plant species utilization, conservation statuses and distribution in the Vhembe Biosphere Reserve, Limpopo Province in South Africa. The hypothesis of this study states that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices. Since the current study is ethnobotanical in nature that is focusing on human interactions with plants, the research methods used addressed multidisciplinary aspects and involved disciplinary integration. An integrated participatory research approach focusing on shared learning, forging collaborative relations with participants, analyzing and validating the shared knowledge was used to document ethnobotanical data within the study area. This research approach was selected as it is considered to be a quick and effective way of acquiring data associated with indigenous knowledge systems. To offset the elements of bias during data collection, the research technique was designed to accommodate core principles that interlinked participatory rural appraisal (PRA) and rapid rural appraisal (RRA). Furthermore, the integrated core principles of participatory rural appraisal and rapid rural appraisal were used with conventional methods such as field surveys and interviews using questionnaires. Therefore, ethnobotanical data were collected through interviews with 203 participants. The data associated with threatened plant’s population size were gathered through literal counting of individual plants as per the IUCN’s Red List Criteria. Data associated with the conservation statuses were gathered from both the South African National Biodiversity Institute and IUCN databases. A total of 13 useful threatened plants belonging to 12 families were recorded with their conservation statuses ranging from being Vulnerable to Critically Endangered. The majority of the threatened plant species (46.0percent) were used for medicinal purposes only, followed by species used for medicinal purposes and as ornamentals (23.0percent). The frequently cited useful threatened species with use values (UV) > 0.024, relative frequency citation (RFC) > 0.059 and fidelity level percentage (FLpercent) > 5.911percent, included Asparagus sekukuniensis, Bowiea volubilis, Brackenridgea zanguebarica, Ocotea bullata, Rhynchosia vendae, Siphonochilus aethiopicus and Warburgia salutaris. About 47.0percent of the recorded useful threatened plants were distributed in remote areas of the Thathe Vonḓo and its surroundings. Threatened plants with population size < 100 adult individuals constituted the majority (61.54percent). Birdlime-making plant species were also documented in the current study. A total of 12 birdlime-making plants belonging to six families were recorded, including threatened Huernia nouhuysii, which is categorized as Vulnerable in South Africa. Amongst the recorded families, Loranthaceae and Euphorbiaceae were categorized as the most frequently utilized families. Among the recorded species, six of them were reported to being used in the birdlime-making for the first time and these species include Euphorbia pulvinata (17.2percent), followed by Tapinanthus forbesii (8percent), Tapinanthus rubromarginatus (7.2percent), Erianthemum ngamicum (7.2percent), Englerophytum magalismon-tanum (3.6percent), Huernia nouhuysii (2.0percent), and Euphorbia tirucalli (0.8percent). Only three plant parts were utilized for birdlime-making. The milky latex was preferred plant part (58.3percent), followed by fruit (33.3percent) and root bark (8.4percent). Birdlime-making techniques involved crushing, which accounted for 55.7percent, followed by air blown (29.6percent) and boiling (14.7percent). Furthermore, the complementary contribution of birdlime toward human development included, being used for bird hunting or trapping small birds (45.8percent), adhesion (23.2percent), teeth cleaning (17.2percent) and roof-waterproofing (13.8percent). The indigenous conservation strategies employed by participants included harvesting of single lateral root per individual medicinal plant (15.3percent), medicinal and timber materials are only harvested during winter season (16.7percent), the use of moist soil to cover injured plant part after bark harvest (18.2percent), prohibit harvesting of and/ or from an injured plant (11.8percent), collection of dried or fallen plants for firewood (8.4percent), issuing of permits by traditional council through the chief or headman to allow collection of medicinal materials and timber (9.9percent), prohibit chopping down of medicinal plant species (13.8percent) and collection of some Critically Endangered plant species such as Brackenridgea zanguebarica and Siphonochilus aethiopicus during the night by authorized people only (5.9percent). The hypothesis which stated that traditional knowledge about utilization, distribution and conservation statuses of threatened plant species provide suggestions for appropriate conservation practices can therefore, not be rejected as there is room for further and more detailed ethnobotanical investigations that is focused on human interactions with threatened plant species. The data presented in this thesis could be used as baseline information for formulating new conservation strategies, monitoring and management plans of threatened plant species not only in the Vhembe Biosphere Reserve, but in other regions of South African. This study provided insights associated with ethnomedicinal uses of Asparagus sekukuniensis, Protea laetans and Encephalartos hirsutus. Results of this study could also stimulate interest in other scientific disciplines such as the phytochemistry, pharmacology, bioprocessing, conservation and anthropology involving documentation threatened plant species. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-03
A framework for communicating climate information to rural small-scale farmers in the Eastern Cape Province, South Africa using systems thinking approach
- Pindura, Tineyi Herbert https://orcid.org/0000-0001-7233-6222
- Authors: Pindura, Tineyi Herbert https://orcid.org/0000-0001-7233-6222
- Date: 2022-02
- Subjects: Farms, Small , Agriculture -- Environmental aspects , Climatic changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22809 , vital:52784
- Description: In the Eastern Cape of South Africa, rural small-scale farmers live in uncertain times characterized by climate change and variability, which intensify social, political and financial inequalities. Therefore, there is a need to increase the understanding and interpretation of climate information to minimize crop production risk, reduce rural small-scale farmers’ vulnerability to climate, and maximize opportunities. Increasing the resilience among rural small-scale farmers requires appropriate and viable practical approaches. By using systems thinking approach (and the Raymond Mhlaba Municipality in the Eastern Cape as a study area), this research disseminates the complex nature of current climate information frameworks. Through inputs from farmers (through a Farmers Research Group methodology) and climate data, this thesis developed a new framework for communicating climate information (herein referred as the climate information communication systems framework) to rural small-scale farmers. The proposed climate information communication systems framework successfully integrates scientific and traditional knowledge. The framework constitutes certain stages, where the farming system and crop identification is the first stage. The second stage is the requirements stage, which has two relationships: scientist to crop requirements and farmers to crop requirements. At the scientist to crop requirements level, users will examine crop requirements by combining climatic data and crop simulations, while at the farmers to crop requirement, rural small-scale farmers use the scientific information to plan for the farming season. The farmer then decides the planting and growing period as well as the harvest timing. The study suggests that building links between rural small-scale farmers, extension officers, and scientists makes sharing information easier. The proposed climate information framework design illustrates that stakeholders now have a personal relationship with climate information transmission and can influence the different actions to reduce the effect of climate change unpredictability. The study established that climate change and variability influence recent agricultural output trends. Recent temperature and rainfall trends could have resulted in low crop productivity in the study area. The study also reflected that women are a critical resource in agriculture and rural economy and that middle-aged men and youth are less interested in farming. The findings also showed that women are more receptive to climate information; hence, to promote access and use of climate information remains vital to consider gender-specific aspects for appropriate decision-making in the agriculture sector. The study also recommends enhancing the Farmers Research Group technique. In the past, the scope of this methodology has been narrowly focused, and it must be explored to incorporate additional types of climate information and more debate about how climate is related to the decisions farmers for implementation or consideration. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-02
- Authors: Pindura, Tineyi Herbert https://orcid.org/0000-0001-7233-6222
- Date: 2022-02
- Subjects: Farms, Small , Agriculture -- Environmental aspects , Climatic changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22809 , vital:52784
- Description: In the Eastern Cape of South Africa, rural small-scale farmers live in uncertain times characterized by climate change and variability, which intensify social, political and financial inequalities. Therefore, there is a need to increase the understanding and interpretation of climate information to minimize crop production risk, reduce rural small-scale farmers’ vulnerability to climate, and maximize opportunities. Increasing the resilience among rural small-scale farmers requires appropriate and viable practical approaches. By using systems thinking approach (and the Raymond Mhlaba Municipality in the Eastern Cape as a study area), this research disseminates the complex nature of current climate information frameworks. Through inputs from farmers (through a Farmers Research Group methodology) and climate data, this thesis developed a new framework for communicating climate information (herein referred as the climate information communication systems framework) to rural small-scale farmers. The proposed climate information communication systems framework successfully integrates scientific and traditional knowledge. The framework constitutes certain stages, where the farming system and crop identification is the first stage. The second stage is the requirements stage, which has two relationships: scientist to crop requirements and farmers to crop requirements. At the scientist to crop requirements level, users will examine crop requirements by combining climatic data and crop simulations, while at the farmers to crop requirement, rural small-scale farmers use the scientific information to plan for the farming season. The farmer then decides the planting and growing period as well as the harvest timing. The study suggests that building links between rural small-scale farmers, extension officers, and scientists makes sharing information easier. The proposed climate information framework design illustrates that stakeholders now have a personal relationship with climate information transmission and can influence the different actions to reduce the effect of climate change unpredictability. The study established that climate change and variability influence recent agricultural output trends. Recent temperature and rainfall trends could have resulted in low crop productivity in the study area. The study also reflected that women are a critical resource in agriculture and rural economy and that middle-aged men and youth are less interested in farming. The findings also showed that women are more receptive to climate information; hence, to promote access and use of climate information remains vital to consider gender-specific aspects for appropriate decision-making in the agriculture sector. The study also recommends enhancing the Farmers Research Group technique. In the past, the scope of this methodology has been narrowly focused, and it must be explored to incorporate additional types of climate information and more debate about how climate is related to the decisions farmers for implementation or consideration. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-02
Adsorption of antibiotic-resistant bacteria and their cell-free deoxyribonucleic acid harbouring resistance genes in drinking water with metal oxides
- Authors: Tobechukwu, Anthony Eric
- Date: 2022
- Subjects: Metallic oxides , DNA -- Synthesis , Drinking water
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27787 , vital:69494
- Description: Access to cleaner water is essential to human health. The incidence of Antibiotic Resistant Bacteria ARB in drinking water and subsequent proliferation of Antibiotic Resistance Genes ARGs in drinking water is a concern for public health. The free DNA cassette harboring antibiotic resistance gene in drinking water has been linked with impaired public health. The ARGs allows bacteria to develop resistance towards antibiotics while ARB render antibiotics ineffective. Existing drinking water treatment technologies eg adsorption, ozonation and chlorination, have shown different levels of potency in the removal of conventional water pollutant. These technologies, which operating principles is based on oxidation or mass transfer, have been explored to gained an insight into their efficiency in the removal of ARB ARGs in water treatment. In general, methods that functions by mass transfer of the ARB ARGs is more effectively than bacteria oxidation. Consequently, adsorption technology was chosen using common metal oxide adsorbents. The adsorbents ZnOAg CeO2 and Al2O3 were synthesized via the self propagation combustion method. This method was selected because of the purity of the final product and the energy requirement. One of the challenges in the removal of ARB in drinking water is the release of ARGs. To address this concern, five different ZnOAg heterostructures were synthesized for the removal of Enterococci faecium. ZnOAg was chosen because of the bactericidal and bacteriostatic characteristics. The study revealed that the concentration of the precursors influences the microstructures of the adsorbents; however, it did not significantly affect the adsorption efficiency. The maximum adsorption capacity q34.11 CFUg was obtained for Ag1Zn3.5. The kinetic studies revealed that Ag1Zn1 and Ag1Zn2 adsorbents agreed to the pseudofirst-order kinetic equation and adsorbents Ag2Zn1 Ag3.5Zn1 and Ag1Zn3.5 agreed to the pseudo-second-order kinetic equation. Initial tap-water pH range was beneficial for the adsorption and the pH of the treated tap-water was within the WHO tap water recommendation 6.5 – 8.5 whereas the effect of ionic strength, anionic and cationic interference was insignificant in the adsorption of MDREF onto the different heterostructure. Interestingly the MDREF could retain its cell membrane integrity and resistance genes, suggesting that surface adsorption was the primary mechanism for the removal. Cerium IV oxide CeO2 was selected because of high adsorption towards phosphate, backbone base for DNA. To prevent the problem of antibiotic resistance, we have synthesized a CeO2 adsorbent that exhibit highly positive character in a wide pH range, via the simple self-propagation combustion protocol, for the removal of free DNA harboring antibiotic resistance genes. Molecular characterization of the extracted genes showed that the sizes for E. coli and inherent gyrB genes are 147 and 460 bp with a purity between 19 2.0. The XRD SEM TEM, and PZC results of the as-synthesized CeO2 showed an agglomerate of pure cubic-faced centered material and highly crystalline, with a net charge at pH 6.2. Experimental results revealed that the reaction proceeded via pseudo first-order kinetic, and it is governed by electrostatic attraction. The free- DNA solution pH electrolyte, and competing ions impacted on the adsorption process. Further experimental results showed that the as-synthesized CeO2 adsorbent has the potential to be used for the removal of free DNA harboring ARGs from tap-water even under oxic conditions. Alumina Al2O3 is an abundant adsorbent that has also shown high removal capacity towards phosphate. The highly pure synthesized Al2O3 adsorbent exhibit fluid-like behaviour under Scanning Electron Microscope SEM. The XRD pattern corresponds to αAl2O3. The adsorption kinetics was described by pseudo second orderadsorption capacity 11.7 μgg implying chemisorption, which agrees with the electrostatic force of attraction caused by opposing ions. This result was evident by the effect of different ions in the tap water. The synthesized α-Al2O3 has the potential for the removal of cell free DNA harbouring multiply resistant genes. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
- Authors: Tobechukwu, Anthony Eric
- Date: 2022
- Subjects: Metallic oxides , DNA -- Synthesis , Drinking water
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27787 , vital:69494
- Description: Access to cleaner water is essential to human health. The incidence of Antibiotic Resistant Bacteria ARB in drinking water and subsequent proliferation of Antibiotic Resistance Genes ARGs in drinking water is a concern for public health. The free DNA cassette harboring antibiotic resistance gene in drinking water has been linked with impaired public health. The ARGs allows bacteria to develop resistance towards antibiotics while ARB render antibiotics ineffective. Existing drinking water treatment technologies eg adsorption, ozonation and chlorination, have shown different levels of potency in the removal of conventional water pollutant. These technologies, which operating principles is based on oxidation or mass transfer, have been explored to gained an insight into their efficiency in the removal of ARB ARGs in water treatment. In general, methods that functions by mass transfer of the ARB ARGs is more effectively than bacteria oxidation. Consequently, adsorption technology was chosen using common metal oxide adsorbents. The adsorbents ZnOAg CeO2 and Al2O3 were synthesized via the self propagation combustion method. This method was selected because of the purity of the final product and the energy requirement. One of the challenges in the removal of ARB in drinking water is the release of ARGs. To address this concern, five different ZnOAg heterostructures were synthesized for the removal of Enterococci faecium. ZnOAg was chosen because of the bactericidal and bacteriostatic characteristics. The study revealed that the concentration of the precursors influences the microstructures of the adsorbents; however, it did not significantly affect the adsorption efficiency. The maximum adsorption capacity q34.11 CFUg was obtained for Ag1Zn3.5. The kinetic studies revealed that Ag1Zn1 and Ag1Zn2 adsorbents agreed to the pseudofirst-order kinetic equation and adsorbents Ag2Zn1 Ag3.5Zn1 and Ag1Zn3.5 agreed to the pseudo-second-order kinetic equation. Initial tap-water pH range was beneficial for the adsorption and the pH of the treated tap-water was within the WHO tap water recommendation 6.5 – 8.5 whereas the effect of ionic strength, anionic and cationic interference was insignificant in the adsorption of MDREF onto the different heterostructure. Interestingly the MDREF could retain its cell membrane integrity and resistance genes, suggesting that surface adsorption was the primary mechanism for the removal. Cerium IV oxide CeO2 was selected because of high adsorption towards phosphate, backbone base for DNA. To prevent the problem of antibiotic resistance, we have synthesized a CeO2 adsorbent that exhibit highly positive character in a wide pH range, via the simple self-propagation combustion protocol, for the removal of free DNA harboring antibiotic resistance genes. Molecular characterization of the extracted genes showed that the sizes for E. coli and inherent gyrB genes are 147 and 460 bp with a purity between 19 2.0. The XRD SEM TEM, and PZC results of the as-synthesized CeO2 showed an agglomerate of pure cubic-faced centered material and highly crystalline, with a net charge at pH 6.2. Experimental results revealed that the reaction proceeded via pseudo first-order kinetic, and it is governed by electrostatic attraction. The free- DNA solution pH electrolyte, and competing ions impacted on the adsorption process. Further experimental results showed that the as-synthesized CeO2 adsorbent has the potential to be used for the removal of free DNA harboring ARGs from tap-water even under oxic conditions. Alumina Al2O3 is an abundant adsorbent that has also shown high removal capacity towards phosphate. The highly pure synthesized Al2O3 adsorbent exhibit fluid-like behaviour under Scanning Electron Microscope SEM. The XRD pattern corresponds to αAl2O3. The adsorption kinetics was described by pseudo second orderadsorption capacity 11.7 μgg implying chemisorption, which agrees with the electrostatic force of attraction caused by opposing ions. This result was evident by the effect of different ions in the tap water. The synthesized α-Al2O3 has the potential for the removal of cell free DNA harbouring multiply resistant genes. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
Development and in vitro biological studies of polymer-based wound dressings with a high haemostatic ability for the management of wounds
- Nqoro, Xhamla https://orcid.org/0000-0002-2065-3629
- Authors: Nqoro, Xhamla https://orcid.org/0000-0002-2065-3629
- Date: 2022
- Subjects: Wound healing , Surgical wound infections , Wound treatment equipment industry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27970 , vital:71404
- Description: Wounds are usually accompanied by complications such as excessive bleeding and bacteria invasion. The design of wound dressings that rapidly stop excessive bleeding and inhibit bacterial invasion is crucial to promoting accelerated wound healing. To meet the abovementioned requirements in wound dressings, topical gels were prepared from sodium alginate SA and carboxymethylcellulose CMC. The wound dressings were loaded with an antifibrinolytic agent, tranexamic acid TA, essential oils, and a variety of metal-based nanoparticles, and carbon-based biomaterials. The scanning electron microscopy SEM and X-ray diffraction XRD confirmed the successful formation of the nanoparticles. The prepared formulations exhibited in vitro drug release kinetics that best fitted with the Korsmeyer-Peppas model. These gels exhibited good spreadability and viscosity, showing a shear-thinning behaviour with pH between 6.7 and 7.3, signifying suitability for skin application and ease of application. The prepared topical gels exhibited significant antibacterial effects against gram-negative and gram-positive strains of bacteria. SA EO-based formulations showed high antibacterial activity across all bacterial strains, followed by SA-based formulations compared to CMC-based formulations, which exhibited moderate antibacterial activity. Moreover, the prepared gels showed good cytocompatibility, promoted cell proliferation, and exhibited 80 percent wound closure on day 3 compared to the untreated group, which showed a 38 percent wound reduction in vitro. Excellent blood clotting properties were observed with CMC-based gels compared to other formulations. However, all the prepared formulations exhibited outstanding blood clotting ability compared to the control, showing that they can promote rapid blood coagulation. The features presented by the prepared gels reveal that they are suitable for rapid wound healing , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022
- Authors: Nqoro, Xhamla https://orcid.org/0000-0002-2065-3629
- Date: 2022
- Subjects: Wound healing , Surgical wound infections , Wound treatment equipment industry
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27970 , vital:71404
- Description: Wounds are usually accompanied by complications such as excessive bleeding and bacteria invasion. The design of wound dressings that rapidly stop excessive bleeding and inhibit bacterial invasion is crucial to promoting accelerated wound healing. To meet the abovementioned requirements in wound dressings, topical gels were prepared from sodium alginate SA and carboxymethylcellulose CMC. The wound dressings were loaded with an antifibrinolytic agent, tranexamic acid TA, essential oils, and a variety of metal-based nanoparticles, and carbon-based biomaterials. The scanning electron microscopy SEM and X-ray diffraction XRD confirmed the successful formation of the nanoparticles. The prepared formulations exhibited in vitro drug release kinetics that best fitted with the Korsmeyer-Peppas model. These gels exhibited good spreadability and viscosity, showing a shear-thinning behaviour with pH between 6.7 and 7.3, signifying suitability for skin application and ease of application. The prepared topical gels exhibited significant antibacterial effects against gram-negative and gram-positive strains of bacteria. SA EO-based formulations showed high antibacterial activity across all bacterial strains, followed by SA-based formulations compared to CMC-based formulations, which exhibited moderate antibacterial activity. Moreover, the prepared gels showed good cytocompatibility, promoted cell proliferation, and exhibited 80 percent wound closure on day 3 compared to the untreated group, which showed a 38 percent wound reduction in vitro. Excellent blood clotting properties were observed with CMC-based gels compared to other formulations. However, all the prepared formulations exhibited outstanding blood clotting ability compared to the control, showing that they can promote rapid blood coagulation. The features presented by the prepared gels reveal that they are suitable for rapid wound healing , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022