Application of machine learning, molecular modelling and structural data mining against antiretroviral drug resistance in HIV-1
- Sheik Amamuddy, Olivier Serge André
- Authors: Sheik Amamuddy, Olivier Serge André
- Date: 2020
- Subjects: Machine learning , Molecules -- Models , Data mining , Neural networks (Computer science) , Antiretroviral agents , Protease inhibitors , Drug resistance , Multidrug resistance , Molecular dynamics , Renin-angiotensin system , HIV (Viruses) -- South Africa , HIV (Viruses) -- Social aspects -- South Africa , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115964 , vital:34282
- Description: Millions are affected with the Human Immunodeficiency Virus (HIV) world wide, even though the death toll is on the decline. Antiretrovirals (ARVs), more specifically protease inhibitors have shown tremendous success since their introduction into therapy since the mid 1990’s by slowing down progression to the Acquired Immune Deficiency Syndrome (AIDS). However, Drug Resistance Mutations (DRMs) are constantly selected for due to viral adaptation, making drugs less effective over time. The current challenge is to manage the infection optimally with a limited set of drugs, with differing associated levels of toxicities in the face of a virus that (1) exists as a quasispecies, (2) may transmit acquired DRMs to drug-naive individuals and (3) that can manifest class-wide resistance due to similarities in design. The presence of latent reservoirs, unawareness of infection status, education and various socio-economic factors make the problem even more complex. Adequate timing and choice of drug prescription together with treatment adherence are very important as drug toxicities, drug failure and sub-optimal treatment regimens leave room for further development of drug resistance. While CD4 cell count and the determination of viral load from patients in resource-limited settings are very helpful to track how well a patient’s immune system is able to keep the virus in check, they can be lengthy in determining whether an ARV is effective. Phenosense assay kits answer this problem using viruses engineered to contain the patient sequences and evaluating their growth in the presence of different ARVs, but this can be expensive and too involved for routine checks. As a cheaper and faster alternative, genotypic assays provide similar information from HIV pol sequences obtained from blood samples, inferring ARV efficacy on the basis of drug resistance mutation patterns. However, these are inherently complex and the various methods of in silico prediction, such as Geno2pheno, REGA and Stanford HIVdb do not always agree in every case, even though this gap decreases as the list of resistance mutations is updated. A major gap in HIV treatment is that the information used for predicting drug resistance is mainly computed from data containing an overwhelming majority of B subtype HIV, when these only comprise about 12% of the worldwide HIV infections. In addition to growing evidence that drug resistance is subtype-related, it is intuitive to hypothesize that as subtyping is a phylogenetic classification, the more divergent a subtype is from the strains used in training prediction models, the less their resistance profiles would correlate. For the aforementioned reasons, we used a multi-faceted approach to attack the virus in multiple ways. This research aimed to (1) improve resistance prediction methods by focusing solely on the available subtype, (2) mine structural information pertaining to resistance in order to find any exploitable weak points and increase knowledge of the mechanistic processes of drug resistance in HIV protease. Finally, (3) we screen for protease inhibitors amongst a database of natural compounds [the South African natural compound database (SANCDB)] to find molecules or molecular properties usable to come up with improved inhibition against the drug target. In this work, structural information was mined using the Anisotropic Network Model, Dynamics Cross-Correlation, Perturbation Response Scanning, residue contact network analysis and the radius of gyration. These methods failed to give any resistance-associated patterns in terms of natural movement, internal correlated motions, residue perturbation response, relational behaviour and global compaction respectively. Applications of drug docking, homology-modelling and energy minimization for generating features suitable for machine-learning were not very promising, and rather suggest that the value of binding energies by themselves from Vina may not be very reliable quantitatively. All these failures lead to a refinement that resulted in a highly sensitive statistically-guided network construction and analysis, which leads to key findings in the early dynamics associated with resistance across all PI drugs. The latter experiment unravelled a conserved lateral expansion motion occurring at the flap elbows, and an associated contraction that drives the base of the dimerization domain towards the catalytic site’s floor in the case of drug resistance. Interestingly, we found that despite the conserved movement, bond angles were degenerate. Alongside, 16 Artificial Neural Network models were optimised for HIV proteases and reverse transcriptase inhibitors, with performances on par with Stanford HIVdb. Finally, we prioritised 9 compounds with potential protease inhibitory activity using virtual screening and molecular dynamics (MD) to additionally suggest a promising modification to one of the compounds. This yielded another molecule inhibiting equally well both opened and closed receptor target conformations, whereby each of the compounds had been selected against an array of multi-drug-resistant receptor variants. While a main hurdle was a lack of non-B subtype data, our findings, especially from the statistically-guided network analysis, may extrapolate to a certain extent to them as the level of conservation was very high within subtype B, despite all the present variations. This network construction method lays down a sensitive approach for analysing a pair of alternate phenotypes for which complex patterns prevail, given a sufficient number of experimental units. During the course of research a weighted contact mapping tool was developed to compare renin-angiotensinogen variants and packaged as part of the MD-TASK tool suite. Finally the functionality, compatibility and performance of the MODE-TASK tool were evaluated and confirmed for both Python2.7.x and Python3.x, for the analysis of normals modes from single protein structures and essential modes from MD trajectories. These techniques and tools collectively add onto the conventional means of MD analysis.
- Full Text:
- Date Issued: 2020
- Authors: Sheik Amamuddy, Olivier Serge André
- Date: 2020
- Subjects: Machine learning , Molecules -- Models , Data mining , Neural networks (Computer science) , Antiretroviral agents , Protease inhibitors , Drug resistance , Multidrug resistance , Molecular dynamics , Renin-angiotensin system , HIV (Viruses) -- South Africa , HIV (Viruses) -- Social aspects -- South Africa , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115964 , vital:34282
- Description: Millions are affected with the Human Immunodeficiency Virus (HIV) world wide, even though the death toll is on the decline. Antiretrovirals (ARVs), more specifically protease inhibitors have shown tremendous success since their introduction into therapy since the mid 1990’s by slowing down progression to the Acquired Immune Deficiency Syndrome (AIDS). However, Drug Resistance Mutations (DRMs) are constantly selected for due to viral adaptation, making drugs less effective over time. The current challenge is to manage the infection optimally with a limited set of drugs, with differing associated levels of toxicities in the face of a virus that (1) exists as a quasispecies, (2) may transmit acquired DRMs to drug-naive individuals and (3) that can manifest class-wide resistance due to similarities in design. The presence of latent reservoirs, unawareness of infection status, education and various socio-economic factors make the problem even more complex. Adequate timing and choice of drug prescription together with treatment adherence are very important as drug toxicities, drug failure and sub-optimal treatment regimens leave room for further development of drug resistance. While CD4 cell count and the determination of viral load from patients in resource-limited settings are very helpful to track how well a patient’s immune system is able to keep the virus in check, they can be lengthy in determining whether an ARV is effective. Phenosense assay kits answer this problem using viruses engineered to contain the patient sequences and evaluating their growth in the presence of different ARVs, but this can be expensive and too involved for routine checks. As a cheaper and faster alternative, genotypic assays provide similar information from HIV pol sequences obtained from blood samples, inferring ARV efficacy on the basis of drug resistance mutation patterns. However, these are inherently complex and the various methods of in silico prediction, such as Geno2pheno, REGA and Stanford HIVdb do not always agree in every case, even though this gap decreases as the list of resistance mutations is updated. A major gap in HIV treatment is that the information used for predicting drug resistance is mainly computed from data containing an overwhelming majority of B subtype HIV, when these only comprise about 12% of the worldwide HIV infections. In addition to growing evidence that drug resistance is subtype-related, it is intuitive to hypothesize that as subtyping is a phylogenetic classification, the more divergent a subtype is from the strains used in training prediction models, the less their resistance profiles would correlate. For the aforementioned reasons, we used a multi-faceted approach to attack the virus in multiple ways. This research aimed to (1) improve resistance prediction methods by focusing solely on the available subtype, (2) mine structural information pertaining to resistance in order to find any exploitable weak points and increase knowledge of the mechanistic processes of drug resistance in HIV protease. Finally, (3) we screen for protease inhibitors amongst a database of natural compounds [the South African natural compound database (SANCDB)] to find molecules or molecular properties usable to come up with improved inhibition against the drug target. In this work, structural information was mined using the Anisotropic Network Model, Dynamics Cross-Correlation, Perturbation Response Scanning, residue contact network analysis and the radius of gyration. These methods failed to give any resistance-associated patterns in terms of natural movement, internal correlated motions, residue perturbation response, relational behaviour and global compaction respectively. Applications of drug docking, homology-modelling and energy minimization for generating features suitable for machine-learning were not very promising, and rather suggest that the value of binding energies by themselves from Vina may not be very reliable quantitatively. All these failures lead to a refinement that resulted in a highly sensitive statistically-guided network construction and analysis, which leads to key findings in the early dynamics associated with resistance across all PI drugs. The latter experiment unravelled a conserved lateral expansion motion occurring at the flap elbows, and an associated contraction that drives the base of the dimerization domain towards the catalytic site’s floor in the case of drug resistance. Interestingly, we found that despite the conserved movement, bond angles were degenerate. Alongside, 16 Artificial Neural Network models were optimised for HIV proteases and reverse transcriptase inhibitors, with performances on par with Stanford HIVdb. Finally, we prioritised 9 compounds with potential protease inhibitory activity using virtual screening and molecular dynamics (MD) to additionally suggest a promising modification to one of the compounds. This yielded another molecule inhibiting equally well both opened and closed receptor target conformations, whereby each of the compounds had been selected against an array of multi-drug-resistant receptor variants. While a main hurdle was a lack of non-B subtype data, our findings, especially from the statistically-guided network analysis, may extrapolate to a certain extent to them as the level of conservation was very high within subtype B, despite all the present variations. This network construction method lays down a sensitive approach for analysing a pair of alternate phenotypes for which complex patterns prevail, given a sufficient number of experimental units. During the course of research a weighted contact mapping tool was developed to compare renin-angiotensinogen variants and packaged as part of the MD-TASK tool suite. Finally the functionality, compatibility and performance of the MODE-TASK tool were evaluated and confirmed for both Python2.7.x and Python3.x, for the analysis of normals modes from single protein structures and essential modes from MD trajectories. These techniques and tools collectively add onto the conventional means of MD analysis.
- Full Text:
- Date Issued: 2020
Application of quality by design principles for optimizing process variables of Extrusion and Spheronization of a Captopril Pellet Formulation:
- Veerubhotla, Krishna, Walker, Roderick B
- Authors: Veerubhotla, Krishna , Walker, Roderick B
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/178312 , vital:40098 , DOI: 10.36468/pharmaceutical-sciences.624
- Description: Product development using quality by design is a proactive and risk-based approach that shifts the manufacturing process from empirical to science-based. Risk assessment was performed to identify and analyse risk areas for the manufacture of captopril pellets. Twelve experimental runs were performed using a Plackett-Burman screening design. Pareto plots revealed the effect of formulation and process variables on the responses monitored and facilitated the identification of the most critical parameters for optimization of the formulation. A response surface methodology approach in conjunction with a central composite design was used to optimize the Eudragit® RL 30D (15-30 ml), microcrystalline cellulose (20-40 % w/w), sodium starch glycolate (2-5 % w/w) and spheronizer speed (650-1050 rpm).
- Full Text:
- Date Issued: 2020
- Authors: Veerubhotla, Krishna , Walker, Roderick B
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/178312 , vital:40098 , DOI: 10.36468/pharmaceutical-sciences.624
- Description: Product development using quality by design is a proactive and risk-based approach that shifts the manufacturing process from empirical to science-based. Risk assessment was performed to identify and analyse risk areas for the manufacture of captopril pellets. Twelve experimental runs were performed using a Plackett-Burman screening design. Pareto plots revealed the effect of formulation and process variables on the responses monitored and facilitated the identification of the most critical parameters for optimization of the formulation. A response surface methodology approach in conjunction with a central composite design was used to optimize the Eudragit® RL 30D (15-30 ml), microcrystalline cellulose (20-40 % w/w), sodium starch glycolate (2-5 % w/w) and spheronizer speed (650-1050 rpm).
- Full Text:
- Date Issued: 2020
Application of section 197 of the Labour Relations Act in an insourcing context
- Authors: Mahlati, Nomphelo Miliswa
- Date: 2020
- Subjects: Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/47392 , vital:39974
- Description: The last two decades have been characterised by a phenomenal rise in the outsourcing of services to external service providers. The driver of this trend has been largely economic, since outsourcing offers more competitive price points for the same service at a comparable service level. Beyond the cost saving objective, the rationale for outsourcing has been to drive core strategy. However, with the economic slowdown, declining consumption and production are forcing entrepreneurs to change their way of thinking about the management of companies. Notably, in recent years there has been a small but a growing reversal of this trend where companies that have previously outsourced functions are being brought back in-house. One of the major concerns surrounding these changes of business strategies is the extent to which the employee rights are safeguarded.
- Full Text:
- Date Issued: 2020
- Authors: Mahlati, Nomphelo Miliswa
- Date: 2020
- Subjects: Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/47392 , vital:39974
- Description: The last two decades have been characterised by a phenomenal rise in the outsourcing of services to external service providers. The driver of this trend has been largely economic, since outsourcing offers more competitive price points for the same service at a comparable service level. Beyond the cost saving objective, the rationale for outsourcing has been to drive core strategy. However, with the economic slowdown, declining consumption and production are forcing entrepreneurs to change their way of thinking about the management of companies. Notably, in recent years there has been a small but a growing reversal of this trend where companies that have previously outsourced functions are being brought back in-house. One of the major concerns surrounding these changes of business strategies is the extent to which the employee rights are safeguarded.
- Full Text:
- Date Issued: 2020
Applied phylogeography : mapping the genetic resource of Honeybush across the Cape Floristic Region
- Authors: Galuszynski, Nicholas C
- Date: 2020
- Subjects: Phylogeography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46771 , vital:39655
- Description: Aim: Honeybush tea is a herbal infusion made from members of the Cape Floristic Region (CFR) endemic Cyclopia Vent. Consting of 21 extant species, six are anthropogenically redistributed across the CFR for Honeybush cultivation. However, with no information regarding the distribution and levels of genetic diversity among wild Honeybush populations, anthropogenic translocation of cultivated genotypes may risk disrupting natural genetic diversity patterns. In this thesis, an applied phylogeographic approach is used to provide baseline insights into the spatial structuring of Honeybush genetic diversity. Location: The Cape Floristic Region (CFR), located along the southern Cape of South Africa. Methods: Spatial structuring of evolutionary lineages within Cyclopia are explored at a genus level using data generated from the combination of Anchored Hybrid Enrichment library preparation and high through put sequencing. A High Resolution Melt analysis (HRM) toolkit is then developed to screen haplotype variation across three non-coding chloroplast loci. This HRM toolkit coupled with haplotype confirmation Sanger sequencing is then applied to describe the spatial structuring of genetic diversity in wild populations for two Honeybush species (C. intermedia and C. subternata) and to compare genetic diversity among wild and cultivated populations of three Honeybush species (C. intermedia, C. subternata, and C. longifolia). A reanalysis of published phylogeographic data focusing on CFR plant taxa is used to test if phylogeographic breaks occur across the boundaries among adjacent Centers of Endemism (CoEs). Finally, the low-copy nuclear data set generated via AHE and high throughput sequencing is summarized. Results: Phylogeographic structuring was detected at the inter- and intraspecific levels in Cyclopia. The genus level analysis revealed a strong phylogenetic split between western CFR and eastern CFR endemic species in the nuclear and chloroplast genomes. At the intraspecific level, HRM proved to be a high throughput and accurate tool for haplotype detection, revealing phylogeographic structuring of genetic diversity in C.intermediaand C.subternata. This genetic diversity and structuring was not detected in cultivated Honeybush populations, which appear to have originated from a small number of founding individuals and have experienced a genetic bottleneck. Spatial structuring of genetic lineages is common among CFR plant taxa and the reanalysis of existing data found a significant trend for phylogeographic breaks tooccuracrosstheboundariesamongadjacentCoEs. Finally, over200000baseswere sequenced across 445 low-copy nuclear loci for 14 Cyclopia species. Conclusions: This thesis provides important baseline information on the spatial distribution of wild Honeybush genetic diversity. Phylogeographic structuring is present in wild Honeybush populations. This however is not accounted for in cultivated populations, which may place wild genetic diversity at risk of being disrupted if geneflow among wild and cultivated populations occurs. The results from this thesis should therefore be used to develop precautionary guidelines for the anthropogenic redistribution of Honeybush genetic material for cultivation. Furthermore, the novel insights into regional patterns of phylogeohraphic structuring of plant populations should encourage more efficient and hypothesis driven sampling designs in future phylogeographic work in the CFR. The high throughput sequence data generated in this thesis should transform Cyclopia to a model organism for the study of molecular evolution in the CFR.
- Full Text:
- Date Issued: 2020
- Authors: Galuszynski, Nicholas C
- Date: 2020
- Subjects: Phylogeography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46771 , vital:39655
- Description: Aim: Honeybush tea is a herbal infusion made from members of the Cape Floristic Region (CFR) endemic Cyclopia Vent. Consting of 21 extant species, six are anthropogenically redistributed across the CFR for Honeybush cultivation. However, with no information regarding the distribution and levels of genetic diversity among wild Honeybush populations, anthropogenic translocation of cultivated genotypes may risk disrupting natural genetic diversity patterns. In this thesis, an applied phylogeographic approach is used to provide baseline insights into the spatial structuring of Honeybush genetic diversity. Location: The Cape Floristic Region (CFR), located along the southern Cape of South Africa. Methods: Spatial structuring of evolutionary lineages within Cyclopia are explored at a genus level using data generated from the combination of Anchored Hybrid Enrichment library preparation and high through put sequencing. A High Resolution Melt analysis (HRM) toolkit is then developed to screen haplotype variation across three non-coding chloroplast loci. This HRM toolkit coupled with haplotype confirmation Sanger sequencing is then applied to describe the spatial structuring of genetic diversity in wild populations for two Honeybush species (C. intermedia and C. subternata) and to compare genetic diversity among wild and cultivated populations of three Honeybush species (C. intermedia, C. subternata, and C. longifolia). A reanalysis of published phylogeographic data focusing on CFR plant taxa is used to test if phylogeographic breaks occur across the boundaries among adjacent Centers of Endemism (CoEs). Finally, the low-copy nuclear data set generated via AHE and high throughput sequencing is summarized. Results: Phylogeographic structuring was detected at the inter- and intraspecific levels in Cyclopia. The genus level analysis revealed a strong phylogenetic split between western CFR and eastern CFR endemic species in the nuclear and chloroplast genomes. At the intraspecific level, HRM proved to be a high throughput and accurate tool for haplotype detection, revealing phylogeographic structuring of genetic diversity in C.intermediaand C.subternata. This genetic diversity and structuring was not detected in cultivated Honeybush populations, which appear to have originated from a small number of founding individuals and have experienced a genetic bottleneck. Spatial structuring of genetic lineages is common among CFR plant taxa and the reanalysis of existing data found a significant trend for phylogeographic breaks tooccuracrosstheboundariesamongadjacentCoEs. Finally, over200000baseswere sequenced across 445 low-copy nuclear loci for 14 Cyclopia species. Conclusions: This thesis provides important baseline information on the spatial distribution of wild Honeybush genetic diversity. Phylogeographic structuring is present in wild Honeybush populations. This however is not accounted for in cultivated populations, which may place wild genetic diversity at risk of being disrupted if geneflow among wild and cultivated populations occurs. The results from this thesis should therefore be used to develop precautionary guidelines for the anthropogenic redistribution of Honeybush genetic material for cultivation. Furthermore, the novel insights into regional patterns of phylogeohraphic structuring of plant populations should encourage more efficient and hypothesis driven sampling designs in future phylogeographic work in the CFR. The high throughput sequence data generated in this thesis should transform Cyclopia to a model organism for the study of molecular evolution in the CFR.
- Full Text:
- Date Issued: 2020
Applying blockchain technology to aspects of electronic health records in South Africa: lessons learnt
- Authors: Adlam, Ryno
- Date: 2020
- Subjects: Blockchains (Databases) , Database security Data protection Medical records -- Data processing
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/45996 , vital:39405
- Description: The purpose of this study was to explore the applicability of blockchain technology as a viable alternative for the secure storage and distribution of electronic health records in a South African context. The adoption of electronic health records (EHRs) has grown over recent years. Electronic health records (EHRs) can be seen as electronic versions of patients’ medical history. EHRs promise benefits such as improving the quality of care, reducing medical errors, reducing costs, saving time, and enhancing the availability and sharing of medical records. Blockchain, in simple terms, could be seen as a distributed database controlled by a group of individuals. Blockchain technology differs from other distributed ledger technology by bundling unrelated data into blocks that are chained together in a linked-list manner, hence the name blockchain. Blockchain technology strives to provide desirable features, such as decentralization, immutability, audibility, and transparency. EHRs are traditionally constructed with a cloud-based infrastructure to promote the storing and distribution of medical records. These medical records are commonly stored in a centralized architecture, such as a relational database. The centralized architecture employed by EHRs may present a single point of failure. These kinds of failures may lead to data-breaches. The cloud-based infrastructure is effective and efficient from an availability standpoint. The increased availability of electronic health records has brought forth challenges related to the security and privacy of the patient’s medical records. The sensitive nature of EHRs attracts the attention of cyber-criminals. There has been a rise in the number of data breaches related to electronic health records. The traditional infrastructure used by electronic health records can no longer ensure the privacy and security of patient’s medical records. To determine whether blockchain is a viable alternative to these approaches, the main objective of this study was to compile a technical report on the applicability of aspects of blockchain technology to the secure storage and distribution of electronic health records. The study first conducted a literature review to gather background on the current state of electronic health records and blockchain technology. The results of the literature review were used to compile an initial report. Experiments were conducted with various aspects of blockchain technology to build a technical baseline and to ultimately validate the initial report. The insights gained from the experiments served to refine the initial report into a final technical report. The final deliverable of this study was to devise a technical report. The technical report serves as a generalized overview of the applicability of blockchain technology as a secure storage and distribution mechanism for electronic health records. The main topics covered by the technical report to outline the applicability of blockchain technology to EHRs are as follows: authentication, authorization, audit log, storage and transactions. The insights gained from the study illustrate that permissioned blockchain technology can enhance the traditional AAA security scheme employed by traditional EHRs. The AAA security scheme entails the use of certificate-based authentication and attributebased access control for authorization. Audit logs can be stored in a semi-decentralized architecture that can enhance the security and privacy of audit logs. Using blockchain technology for storing electronic health records might not be a viable alternative to traditional EHRs architecture. Blockchain technology violates certain privacy regulations as information is stored in a permanent manner. Furthermore, blockchain technology is not optimized for dealing with large volumes of data. However, blockchain technology could be used to store a cryptographic hash of electronic health records to ensure the integrity of records. Permissioned blockchain technology can enhance the EHRs transaction process by transacting health records in a peer-to-peer infrastructure. In doing so, the above-mentioned AAA security scheme can enhance the security, confidentiality, and integrity of electronic health records shared across organizational bounds.
- Full Text:
- Date Issued: 2020
- Authors: Adlam, Ryno
- Date: 2020
- Subjects: Blockchains (Databases) , Database security Data protection Medical records -- Data processing
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/45996 , vital:39405
- Description: The purpose of this study was to explore the applicability of blockchain technology as a viable alternative for the secure storage and distribution of electronic health records in a South African context. The adoption of electronic health records (EHRs) has grown over recent years. Electronic health records (EHRs) can be seen as electronic versions of patients’ medical history. EHRs promise benefits such as improving the quality of care, reducing medical errors, reducing costs, saving time, and enhancing the availability and sharing of medical records. Blockchain, in simple terms, could be seen as a distributed database controlled by a group of individuals. Blockchain technology differs from other distributed ledger technology by bundling unrelated data into blocks that are chained together in a linked-list manner, hence the name blockchain. Blockchain technology strives to provide desirable features, such as decentralization, immutability, audibility, and transparency. EHRs are traditionally constructed with a cloud-based infrastructure to promote the storing and distribution of medical records. These medical records are commonly stored in a centralized architecture, such as a relational database. The centralized architecture employed by EHRs may present a single point of failure. These kinds of failures may lead to data-breaches. The cloud-based infrastructure is effective and efficient from an availability standpoint. The increased availability of electronic health records has brought forth challenges related to the security and privacy of the patient’s medical records. The sensitive nature of EHRs attracts the attention of cyber-criminals. There has been a rise in the number of data breaches related to electronic health records. The traditional infrastructure used by electronic health records can no longer ensure the privacy and security of patient’s medical records. To determine whether blockchain is a viable alternative to these approaches, the main objective of this study was to compile a technical report on the applicability of aspects of blockchain technology to the secure storage and distribution of electronic health records. The study first conducted a literature review to gather background on the current state of electronic health records and blockchain technology. The results of the literature review were used to compile an initial report. Experiments were conducted with various aspects of blockchain technology to build a technical baseline and to ultimately validate the initial report. The insights gained from the experiments served to refine the initial report into a final technical report. The final deliverable of this study was to devise a technical report. The technical report serves as a generalized overview of the applicability of blockchain technology as a secure storage and distribution mechanism for electronic health records. The main topics covered by the technical report to outline the applicability of blockchain technology to EHRs are as follows: authentication, authorization, audit log, storage and transactions. The insights gained from the study illustrate that permissioned blockchain technology can enhance the traditional AAA security scheme employed by traditional EHRs. The AAA security scheme entails the use of certificate-based authentication and attributebased access control for authorization. Audit logs can be stored in a semi-decentralized architecture that can enhance the security and privacy of audit logs. Using blockchain technology for storing electronic health records might not be a viable alternative to traditional EHRs architecture. Blockchain technology violates certain privacy regulations as information is stored in a permanent manner. Furthermore, blockchain technology is not optimized for dealing with large volumes of data. However, blockchain technology could be used to store a cryptographic hash of electronic health records to ensure the integrity of records. Permissioned blockchain technology can enhance the EHRs transaction process by transacting health records in a peer-to-peer infrastructure. In doing so, the above-mentioned AAA security scheme can enhance the security, confidentiality, and integrity of electronic health records shared across organizational bounds.
- Full Text:
- Date Issued: 2020
Applying high-resolution remote sensing to quantify baboon damage at a sub-compartment level in pine stands in the Mpumalanga escarpment region of South Africa
- Authors: Ferreira, Regardt
- Date: 2020
- Subjects: Environmental sciences -- Remote sensing , Geographic information systems Remote sensing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49082 , vital:41599
- Description: Managing risk in intensively managed monoculture plantation forests is an essential task to ensure sustainable yield and a continuous flow of forest products. However, since risks can be either biotic or abiotic, not all of them have a predictable pattern of spread, which can cause severe losses if management does not have the chance to implement mitigation action. Monitoring the change in forest health is vital as this provides the opportunity for preventative management and quantifies the amount of damage that management has to deal with. To provide this window of opportunity for appropriate action, constant monitoring is required. Until recently, forest health was measured through field surveys which provided adequate data. This procedure, however, is time consuming. Remote sensing has become very popular as a monitoring tool, due to its ability to provide assessment data in a fraction of the time. In this study, baboon damage in plantations along the Mpumalanga escarpment area of South Africa was monitored using remote sensing methods. While there are many methods of forest health monitoring using remote sensing, some approaches are less suitable as they either monitor damage caused at a plantation level, use lower spatial resolution (>10m) datasets or map damage using one available time period. The purpose of this study was first to establish the impact of baboon damage through time, using Sentinel-2 satellite imagery with all vegetation indices available, and the Extreme Gradient Boosting (XGboost) algorithm. The second part focused on analysing the damage at a tree level using PlanetScope imagery using a deep Learning approach. Overall, the study found that the use of Sentinel-2 data and PlanetScope data could accurately distinguish between the varying severity of baboon damage, achieving an accuracy of 95% and 82%. The processing time of the deep learning Artificial Neural Network (ANN) was greatly affected by the number of hidden layers and neurons used. Implementation of techniques used in this study has the potential to improve the accuracy of forest health monitoring in compartment forestry in South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Ferreira, Regardt
- Date: 2020
- Subjects: Environmental sciences -- Remote sensing , Geographic information systems Remote sensing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49082 , vital:41599
- Description: Managing risk in intensively managed monoculture plantation forests is an essential task to ensure sustainable yield and a continuous flow of forest products. However, since risks can be either biotic or abiotic, not all of them have a predictable pattern of spread, which can cause severe losses if management does not have the chance to implement mitigation action. Monitoring the change in forest health is vital as this provides the opportunity for preventative management and quantifies the amount of damage that management has to deal with. To provide this window of opportunity for appropriate action, constant monitoring is required. Until recently, forest health was measured through field surveys which provided adequate data. This procedure, however, is time consuming. Remote sensing has become very popular as a monitoring tool, due to its ability to provide assessment data in a fraction of the time. In this study, baboon damage in plantations along the Mpumalanga escarpment area of South Africa was monitored using remote sensing methods. While there are many methods of forest health monitoring using remote sensing, some approaches are less suitable as they either monitor damage caused at a plantation level, use lower spatial resolution (>10m) datasets or map damage using one available time period. The purpose of this study was first to establish the impact of baboon damage through time, using Sentinel-2 satellite imagery with all vegetation indices available, and the Extreme Gradient Boosting (XGboost) algorithm. The second part focused on analysing the damage at a tree level using PlanetScope imagery using a deep Learning approach. Overall, the study found that the use of Sentinel-2 data and PlanetScope data could accurately distinguish between the varying severity of baboon damage, achieving an accuracy of 95% and 82%. The processing time of the deep learning Artificial Neural Network (ANN) was greatly affected by the number of hidden layers and neurons used. Implementation of techniques used in this study has the potential to improve the accuracy of forest health monitoring in compartment forestry in South Africa.
- Full Text:
- Date Issued: 2020
Applying the substitution augmentation modification redefinition model towards adoption of e-learning usage at Walter Sisulu University
- Authors: Mabona, Teoflax Anele
- Date: 2020
- Subjects: Educational technology -- South Africa Universities and colleges -- Computer-assisted instruction -- South Africa
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/49474 , vital:41724
- Description: The adoption of e-learning by universities around the world has grown drastically during this time of the Fourth Industrial Revolution. Most universities implement the full utilisation of e-learning, conducting classes only by using online course delivery. Some universities still prefer a blended learning approach where classes are presented to students using both the traditional way of teaching and online e-learning platforms. Walter Sisulu University (WSU) is one of those universities that uses blended learning. The university started using this approach in 2009, through a partnership between WSU and the Netherlands for learning and teaching enhancement using e-learning. The adoption and usage of e-learning in universities is a challenge, which some researchers have investigated. This study aimed to apply the Substitution; Augmentation; Modification; Redefinition (SAMR) Model to enhance the adoption of e-learning and its usage at WSU. To obtain results, a quantitative method using approaches, such as WiseUp logs, WiseUp e-learning usage publications, WSU e-learning documents and literature, was applied. The study, according to the WiseUp logs, found that the e-learning levels at the university were low. Using the WiseUp e-learning usage publications, revealed that the university was still having some challenges regarding the low usage of WiseUp. Some of the students were not aware of the WiseUp platform as they said the system was only shown to them once and never again for continuous training. Most lecturers’ challenge was that the system was time-consuming to upload online content. This study used the WSU e-learning documents to show that the institution employed some initiatives for the adoption and usage of WiseUp, such as the LTD (Learning Teaching Development) department orientating students about WiseUp, just after their registration. The study ‘s objective was achieved, which was to apply the Substitution; Augmentation; Modification; Redefinition (SAMR) Model to enhance the adoption and usage of e-learning at WSU. The study applied the Substitution; Augmentation; Modification; Redefinition (SAMR) Model to provide a clear understanding of WSU’s position in terms of e-learning adoption and usage. The overall result from the study showed that WSU was based mostly on the first three levels of teaching and learning integration into technology, and in the enhancement level of the Substitution; Augmentation; Modification; Redefinition (SAMR) Model. The researcher noted that much still needed to be done because the usage of the system was still very low but its integration into teaching and learning was positive.
- Full Text:
- Date Issued: 2020
- Authors: Mabona, Teoflax Anele
- Date: 2020
- Subjects: Educational technology -- South Africa Universities and colleges -- Computer-assisted instruction -- South Africa
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/49474 , vital:41724
- Description: The adoption of e-learning by universities around the world has grown drastically during this time of the Fourth Industrial Revolution. Most universities implement the full utilisation of e-learning, conducting classes only by using online course delivery. Some universities still prefer a blended learning approach where classes are presented to students using both the traditional way of teaching and online e-learning platforms. Walter Sisulu University (WSU) is one of those universities that uses blended learning. The university started using this approach in 2009, through a partnership between WSU and the Netherlands for learning and teaching enhancement using e-learning. The adoption and usage of e-learning in universities is a challenge, which some researchers have investigated. This study aimed to apply the Substitution; Augmentation; Modification; Redefinition (SAMR) Model to enhance the adoption of e-learning and its usage at WSU. To obtain results, a quantitative method using approaches, such as WiseUp logs, WiseUp e-learning usage publications, WSU e-learning documents and literature, was applied. The study, according to the WiseUp logs, found that the e-learning levels at the university were low. Using the WiseUp e-learning usage publications, revealed that the university was still having some challenges regarding the low usage of WiseUp. Some of the students were not aware of the WiseUp platform as they said the system was only shown to them once and never again for continuous training. Most lecturers’ challenge was that the system was time-consuming to upload online content. This study used the WSU e-learning documents to show that the institution employed some initiatives for the adoption and usage of WiseUp, such as the LTD (Learning Teaching Development) department orientating students about WiseUp, just after their registration. The study ‘s objective was achieved, which was to apply the Substitution; Augmentation; Modification; Redefinition (SAMR) Model to enhance the adoption and usage of e-learning at WSU. The study applied the Substitution; Augmentation; Modification; Redefinition (SAMR) Model to provide a clear understanding of WSU’s position in terms of e-learning adoption and usage. The overall result from the study showed that WSU was based mostly on the first three levels of teaching and learning integration into technology, and in the enhancement level of the Substitution; Augmentation; Modification; Redefinition (SAMR) Model. The researcher noted that much still needed to be done because the usage of the system was still very low but its integration into teaching and learning was positive.
- Full Text:
- Date Issued: 2020
Approaches used by NGOs in managing HIV/AIDS programmes in the Eastern Cape
- Authors: Budaza, Silakhe
- Date: 2020
- Subjects: HIV(Disease)-- Psychological aspects -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/49775 , vital:41799
- Description: The purpose of this research study was to explore the interventions NGOs used in addressing the prevalence of HIV/AIDS along with an exploration of the management and causal factors behind project failures and success. Five districts in the province of the Eastern Cape, South Africa were used in the study. The study had three objectives- the first being to identify the various approaches used to manage HIV/AIDS by NGOs; the second was to consider the influence HIV/AIDS policies on the health sector NGOs and finally the third objective of the study was to explore the monitoring and evaluation mechanism set in place to track progress, or lack of, in HIV/AIDS programs. The research design followed a qualitative methodology and data was gathered from ten participants through semi-structured interviews and supported by a document analysis of existing HIV and AIDS policies from both a national and provincial level which were qualitative. The findings showed that a lack of adequate or delayed funding affected the overall performance of NGOs as well as approaches such as home-based care and educational support programs. Resource mobilization and fundraising ought to be diversified so that there is a committed and varied pool of funds to enable the execution of HIV/AIDS services and programs. The government and other stakeholders should build on local capacity to implement these various programs and build financial, social and organizational sustainability.
- Full Text:
- Date Issued: 2020
- Authors: Budaza, Silakhe
- Date: 2020
- Subjects: HIV(Disease)-- Psychological aspects -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/49775 , vital:41799
- Description: The purpose of this research study was to explore the interventions NGOs used in addressing the prevalence of HIV/AIDS along with an exploration of the management and causal factors behind project failures and success. Five districts in the province of the Eastern Cape, South Africa were used in the study. The study had three objectives- the first being to identify the various approaches used to manage HIV/AIDS by NGOs; the second was to consider the influence HIV/AIDS policies on the health sector NGOs and finally the third objective of the study was to explore the monitoring and evaluation mechanism set in place to track progress, or lack of, in HIV/AIDS programs. The research design followed a qualitative methodology and data was gathered from ten participants through semi-structured interviews and supported by a document analysis of existing HIV and AIDS policies from both a national and provincial level which were qualitative. The findings showed that a lack of adequate or delayed funding affected the overall performance of NGOs as well as approaches such as home-based care and educational support programs. Resource mobilization and fundraising ought to be diversified so that there is a committed and varied pool of funds to enable the execution of HIV/AIDS services and programs. The government and other stakeholders should build on local capacity to implement these various programs and build financial, social and organizational sustainability.
- Full Text:
- Date Issued: 2020
Approaches used by NGOs in managing HIV/AIDS programmes in the Eastern Cape
- Authors: Budaza, Silakhe
- Date: 2020
- Subjects: Non-governmental organizations -- South Africa , Disease management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/50457 , vital:42169
- Description: The purpose of this research study was to explore the interventions NGOs used in addressing the prevalence of HIV/AIDS along with an exploration of the management and causal factors behind project failures and success. Five districts in the province of the Eastern Cape, South Africa were used in the study. The study had three objectives- the first being to identify the various approaches used to manage HIV/AIDS by NGOs; the second was to consider the influence HIV/AIDS policies on the health sector NGOs and finally the third objective of the study was to explore the monitoring and evaluation mechanism set in place to track progress, or lack of, in HIV/AIDS programs. The research design followed a qualitative methodology and data was gathered from ten participants through semi-structured interviews and supported by a document analysis of existing HIV and AIDS policies from both a national and provincial level which were qualitative. The findings showed that a lack of adequate or delayed funding affected the overall performance of NGOs as well as approaches such as home-based care and educational support programs. In addition, the negative stigma associated with HIV/AIDS has been a looming issue since 2004 which continues to undermine efforts of NGOs in their means to manage HIV/AIDS. The consequences of stigma from the findings are treatment adherence issues and little to no attendance of HIV/AIDS programs provided by the respective NGOs. Effective planning and management along with capacitated staff and volunteers increased the positive outcome of HIV/AIDS programs and services offered by the NGOs. From the study findings, it is recommended that the planning of HIV/AIDS approaches should consider resource planning to avoid abandoning projects midway due to a lack of resources. The management and monitoring of NGOs within the health sector, dealing with epidemics such as HIV/AIDS need to build on flexibility in implementation and have effective risk assessments in place as a contingency, so that corrective action is taken. Resource mobilization and fundraising ought to be diversified so that there is a committed and varied pool of funds to enable the execution of HIV/AIDS services and programs. The government and other stakeholders should build on local capacity to implement these various programs and also build financial, social and organizational sustainability.
- Full Text:
- Date Issued: 2020
- Authors: Budaza, Silakhe
- Date: 2020
- Subjects: Non-governmental organizations -- South Africa , Disease management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/50457 , vital:42169
- Description: The purpose of this research study was to explore the interventions NGOs used in addressing the prevalence of HIV/AIDS along with an exploration of the management and causal factors behind project failures and success. Five districts in the province of the Eastern Cape, South Africa were used in the study. The study had three objectives- the first being to identify the various approaches used to manage HIV/AIDS by NGOs; the second was to consider the influence HIV/AIDS policies on the health sector NGOs and finally the third objective of the study was to explore the monitoring and evaluation mechanism set in place to track progress, or lack of, in HIV/AIDS programs. The research design followed a qualitative methodology and data was gathered from ten participants through semi-structured interviews and supported by a document analysis of existing HIV and AIDS policies from both a national and provincial level which were qualitative. The findings showed that a lack of adequate or delayed funding affected the overall performance of NGOs as well as approaches such as home-based care and educational support programs. In addition, the negative stigma associated with HIV/AIDS has been a looming issue since 2004 which continues to undermine efforts of NGOs in their means to manage HIV/AIDS. The consequences of stigma from the findings are treatment adherence issues and little to no attendance of HIV/AIDS programs provided by the respective NGOs. Effective planning and management along with capacitated staff and volunteers increased the positive outcome of HIV/AIDS programs and services offered by the NGOs. From the study findings, it is recommended that the planning of HIV/AIDS approaches should consider resource planning to avoid abandoning projects midway due to a lack of resources. The management and monitoring of NGOs within the health sector, dealing with epidemics such as HIV/AIDS need to build on flexibility in implementation and have effective risk assessments in place as a contingency, so that corrective action is taken. Resource mobilization and fundraising ought to be diversified so that there is a committed and varied pool of funds to enable the execution of HIV/AIDS services and programs. The government and other stakeholders should build on local capacity to implement these various programs and also build financial, social and organizational sustainability.
- Full Text:
- Date Issued: 2020
Arid-adapted paradiaptomid copepods contribute to mosquito regulation
- Cuthbert, Ross N, Wasserman, Ryan J, Dalu, Tatenda
- Authors: Cuthbert, Ross N , Wasserman, Ryan J , Dalu, Tatenda
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443260 , vital:74103 , https://hdl.handle.net/10520/ejc-afzoo-v55-n3-a1
- Description: We are writing to describe the predatory potential of calanoid copepods for the regulation of mosquito larval populations in aquatic environments. Mosquito-borne diseases continue to drive unparalleled human morbidity and mortality (Ferguson 2018), and directly threaten other wildlife (George et al. 2015). This disease burden is most concentrated in Sub-Saharan Africa, where aquatic habitats exploited by mosquitoes are often temporary and, under natural conditions, characterised by arid-adapted ecological communities. These communities can be predator rich, contributing to the regulation of aquatic larval mosquito populations and therefore the adult vectors of the diseases at the landscape scale. A newly described southern African copepod species, Lovenula raynerae Suárez-Morales, Wasserman and Dalu 2015 (Paradiaptominae) (Figure 1), has been identified as an efficacious predatory agent for the natural regulation of medically important mosquito populations in temporary aquatic environments (Cuthbert et al. 2018).
- Full Text:
- Date Issued: 2020
- Authors: Cuthbert, Ross N , Wasserman, Ryan J , Dalu, Tatenda
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443260 , vital:74103 , https://hdl.handle.net/10520/ejc-afzoo-v55-n3-a1
- Description: We are writing to describe the predatory potential of calanoid copepods for the regulation of mosquito larval populations in aquatic environments. Mosquito-borne diseases continue to drive unparalleled human morbidity and mortality (Ferguson 2018), and directly threaten other wildlife (George et al. 2015). This disease burden is most concentrated in Sub-Saharan Africa, where aquatic habitats exploited by mosquitoes are often temporary and, under natural conditions, characterised by arid-adapted ecological communities. These communities can be predator rich, contributing to the regulation of aquatic larval mosquito populations and therefore the adult vectors of the diseases at the landscape scale. A newly described southern African copepod species, Lovenula raynerae Suárez-Morales, Wasserman and Dalu 2015 (Paradiaptominae) (Figure 1), has been identified as an efficacious predatory agent for the natural regulation of medically important mosquito populations in temporary aquatic environments (Cuthbert et al. 2018).
- Full Text:
- Date Issued: 2020
Assessing community structure and trophic interrelationships in three differently impacted headwater streams in the AmatholeWinterberg freshwater ecoregion, South Africa
- Authors: Matomela, Nonjabulo Happy
- Date: 2020
- Subjects: Stream ecology -- South Africa -- Eastern Cape , Freshwater animals -- Ecology -- South Africa -- Eastern Cape , Kat River (South Africa) -- , Lushington River (South Africa) , Elands River (South Africa) , Eyre River (South Africa) , Food chains (Ecology) -- South Africa -- Eastern Cape , Water quality -- South Africa -- Eastern Cape , Land use -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/147653 , vital:38658
- Description: Afromontane regions represent some of the highly threatened ecosystems on the planet as they harbour endemic and often relic freshwater fauna. These ecologically sensitive ecosystems have been altered by multiple impacts, including invasion by non-native fishes, replacement of diverse indigenous vegetation with monoculture plantations, agricultural and mining activities, hydrological modifications, and degradation of instream habitats, with potential detrimental effects on aquatic community structures and food web dynamics. The aim of the present study was to compare spatio-temporal patterns of macroinvertebrate and fish communities as well as food web dynamics in three differently impacted headwater tributaries of the Kat River in the Amathole-Winterberg freshwater ecoregion in the Eastern Cape Province of South Africa. The upper Kat River catchment was the ideal model for purposes of the present study as it contains streams with varying degrees of human impact. The streams considered in the present study were (i) the Eyre River which was considered to closely represent near-natural conditions as it is the least impacted stream in this catchment, with the riparian zone dominated by relatively intact and diverse native woody vegetation, (ii) the Elands River whose catchment has been altered by agricultural activities, and (iii) the Lushington River, whose riparian zone has been heavily invaded by black wattle. The three headwater streams were generally distinguished based on the physical-chemical variables. The Elands River was characterised by high conductivity and total dissolved solids (TDS). In addition, the Elands River was more alkaline and relatively warmer than the other two rivers. This suggested the negative influence of agriculture activities on the water quality in the Elands River. In general, the Lushington and Eyre rivers had comparable physical and chemical variables. However, the Lushington River was generally characterised by low streamflow, likely as a consequent of black wattle which is known for altering hydrological regimes of streams .The Eyre River and Lushington River were comparable in terms of macroinvertebrate richness and diversity, whereas the Elands River was characterised by low macroinvertebrate diversity and richness. Redundancy analysis indicated that the macroinvertebrate communities were mostly influenced by seasonality, with land-use accounting for a small but significant difference in community composition. In comparison, the generalised linear mixed-effects models (GLMMs) showed that chubbyhead barb abundance was significantly influenced by land-use patterns. Evaluation of food web dynamics using stable isotope analysis revealed that the food web structure in the three rivers differed substantially as a result of land-use. Specifically, the Eyre River was characterised by less variation in stable isotope values of basal food sources and consequently, the consumer groups had a narrow isotopic breadth. In contrast, the Elands River was characterised by a wide variation in basal food sources and therefore, a wider isotopic breadth for consumers. The Lushington River was spatially variable in terms of basal sources and isotopic breadth for consumers. The study concluded that food webs and trophic interrelationships were a more informative indicator of land-use than community structure was in evaluating the impact of land-use patterns on aquatic communities. In addition, future studies should seek to investigate food webs interrelationships in addition to community structure to infer a more conclusive river assessment.
- Full Text:
- Date Issued: 2020
- Authors: Matomela, Nonjabulo Happy
- Date: 2020
- Subjects: Stream ecology -- South Africa -- Eastern Cape , Freshwater animals -- Ecology -- South Africa -- Eastern Cape , Kat River (South Africa) -- , Lushington River (South Africa) , Elands River (South Africa) , Eyre River (South Africa) , Food chains (Ecology) -- South Africa -- Eastern Cape , Water quality -- South Africa -- Eastern Cape , Land use -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/147653 , vital:38658
- Description: Afromontane regions represent some of the highly threatened ecosystems on the planet as they harbour endemic and often relic freshwater fauna. These ecologically sensitive ecosystems have been altered by multiple impacts, including invasion by non-native fishes, replacement of diverse indigenous vegetation with monoculture plantations, agricultural and mining activities, hydrological modifications, and degradation of instream habitats, with potential detrimental effects on aquatic community structures and food web dynamics. The aim of the present study was to compare spatio-temporal patterns of macroinvertebrate and fish communities as well as food web dynamics in three differently impacted headwater tributaries of the Kat River in the Amathole-Winterberg freshwater ecoregion in the Eastern Cape Province of South Africa. The upper Kat River catchment was the ideal model for purposes of the present study as it contains streams with varying degrees of human impact. The streams considered in the present study were (i) the Eyre River which was considered to closely represent near-natural conditions as it is the least impacted stream in this catchment, with the riparian zone dominated by relatively intact and diverse native woody vegetation, (ii) the Elands River whose catchment has been altered by agricultural activities, and (iii) the Lushington River, whose riparian zone has been heavily invaded by black wattle. The three headwater streams were generally distinguished based on the physical-chemical variables. The Elands River was characterised by high conductivity and total dissolved solids (TDS). In addition, the Elands River was more alkaline and relatively warmer than the other two rivers. This suggested the negative influence of agriculture activities on the water quality in the Elands River. In general, the Lushington and Eyre rivers had comparable physical and chemical variables. However, the Lushington River was generally characterised by low streamflow, likely as a consequent of black wattle which is known for altering hydrological regimes of streams .The Eyre River and Lushington River were comparable in terms of macroinvertebrate richness and diversity, whereas the Elands River was characterised by low macroinvertebrate diversity and richness. Redundancy analysis indicated that the macroinvertebrate communities were mostly influenced by seasonality, with land-use accounting for a small but significant difference in community composition. In comparison, the generalised linear mixed-effects models (GLMMs) showed that chubbyhead barb abundance was significantly influenced by land-use patterns. Evaluation of food web dynamics using stable isotope analysis revealed that the food web structure in the three rivers differed substantially as a result of land-use. Specifically, the Eyre River was characterised by less variation in stable isotope values of basal food sources and consequently, the consumer groups had a narrow isotopic breadth. In contrast, the Elands River was characterised by a wide variation in basal food sources and therefore, a wider isotopic breadth for consumers. The Lushington River was spatially variable in terms of basal sources and isotopic breadth for consumers. The study concluded that food webs and trophic interrelationships were a more informative indicator of land-use than community structure was in evaluating the impact of land-use patterns on aquatic communities. In addition, future studies should seek to investigate food webs interrelationships in addition to community structure to infer a more conclusive river assessment.
- Full Text:
- Date Issued: 2020
Assessing factors that mitigate business risks in the operations of emerging black-owned businesses in Mthatha, Eastern Cape
- Authors: Bovungana, Afrika Khanyiso
- Date: 2020
- Subjects: Business enterprises, Black
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/47502 , vital:40121
- Description: The study sought to assessfactors that mitigate business risks in the operations of emerging black-owned businesses in Mthatha, Eastern Cape. Small businesses in the country are significant contributorsto the South African economy,as they provide employment and development opportunities to disadvantaged communities. Many of these businesses are operationalbut have no formal systems in place to operate effectively. The lack of proper operating procedures can result ininefficiencies that often lead to the collapse and eventual failure of these businesses. Van Vuuren,a professor at the University of Pretoria,mentionedin a round table dialogue that in South Africa the early stage entrepreneurial activity rate has been recorded as9.2% whereas in similar developing economies such as Brazil early stage entrepreneurialactivity isapproximately 40%. The study utilised a quantitative research design and employed a Likert scale questionnaire on a sample of 64 black-owned small, medium and micro enterprises (SMMEs) chosen by means of a random probability samplingmethod. QuestionPro was used to analyse the data and discuss the findings of the study.The various factors identified and highlighted indicate the integral challenges faced by the black-owned SMMEs remain prevalent. The success or failure is dependent on dynamic interventions that are taken into consideration and implemented for the improvement of the environment and business life cycle of black-owned businesses.
- Full Text:
- Date Issued: 2020
- Authors: Bovungana, Afrika Khanyiso
- Date: 2020
- Subjects: Business enterprises, Black
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/47502 , vital:40121
- Description: The study sought to assessfactors that mitigate business risks in the operations of emerging black-owned businesses in Mthatha, Eastern Cape. Small businesses in the country are significant contributorsto the South African economy,as they provide employment and development opportunities to disadvantaged communities. Many of these businesses are operationalbut have no formal systems in place to operate effectively. The lack of proper operating procedures can result ininefficiencies that often lead to the collapse and eventual failure of these businesses. Van Vuuren,a professor at the University of Pretoria,mentionedin a round table dialogue that in South Africa the early stage entrepreneurial activity rate has been recorded as9.2% whereas in similar developing economies such as Brazil early stage entrepreneurialactivity isapproximately 40%. The study utilised a quantitative research design and employed a Likert scale questionnaire on a sample of 64 black-owned small, medium and micro enterprises (SMMEs) chosen by means of a random probability samplingmethod. QuestionPro was used to analyse the data and discuss the findings of the study.The various factors identified and highlighted indicate the integral challenges faced by the black-owned SMMEs remain prevalent. The success or failure is dependent on dynamic interventions that are taken into consideration and implemented for the improvement of the environment and business life cycle of black-owned businesses.
- Full Text:
- Date Issued: 2020
Assessing invasive alien aquatic plant species, phytoremediation effects using biological indicators in the Swartkops River system
- Authors: Tshithukhe, Getrude
- Date: 2020
- Subjects: Aquatic weeds -- Biological control -- South Africa -- Eastern Cape , Alien plants -- Biological control -- South Africa -- Eastern Cape , Phytoremediation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167665 , vital:41501
- Description: Pollution effluents in freshwater ecosystems are becoming increasingly ubiquitous as a result of cumulative anthropogenic activities, such as wastewater treatments works, and industrial, agricultural and mining activities. These activities are more noticeable in urban river atchments where there is greater human population densities and industrial developments. The ecological effects of anthropogenic activities on freshwater ecosystems include: excessive deposition of contaminants such as nutrients, pharmaceuticals, microplastics and other chemicals, which change physicochemical properties, causing a decline in aquatic biodiversity. These effects, impact negatively on the resilience of freshwater, making the systems vulnerable to invasion by alien aquatic plants. Ultimately, the loss of local biodiversity associated with the invasive alien aquatic plants (IAAP) results in a loss of some ecosystem goods and services. The Swartkops River system, Eastern Cape Province, drains most of the neighbouring formal and informal settlements, agricultural lands and industries, and hence is exposed to water pollution from human activities along the river catchment. Various water quality assessments are needed to evaluate the extent of pollutants and their impacts on the river ecosystem. Phytoremediation is one approach employed internationally for removing harmful nutrients and chemicals in freshwater ecosystems. Most studies measure the success of phytoremediation through measuring the reduction of contaminants in water or soil chemistry in mesocosm settings, which may not take into account all the important environmental factors that exist in the field. The present study assesses the phytoremediation potential of Pontederia (Eichhornia) crassipes and Salvinia molesta by evaluating water and sediment chemistry, periphyton and aquatic macroinvertebrate community recovery along seven field sites (excluding IAAP species mats sites) located upstream and downstream IAAP species mats on the Swartkops River between April and September 2018. Water and sediment samples were collected once monthly on ten seven field sites, including the IAAP species mat sites. Periphyton and aquatic macroinvertebrates were collected on seven sites, excluding the IAAP mat sites. Pontederia crassipes and S. molesta infestation in Swartkops River showed positive phytoremediation results and improved some water and sediment chemistry in the downstream treatments as compared to upstream treatments. Although there were some fluctuations with some variables, important water and sediment chemistry were reduced downstream. By contrast, biological assessment results did not show any response to the presence of IAAP species and phytoremediation. Periphyton and aquatic macroinvertebrates diversity and community assemblages were more influenced by water quality. Although IAAP species did provide improvement in water and sediments chemistry, multiple effluent point and non-point sources in Swartkops outpaced phytoremediation. Taxa evenness and relative taxa abundance showed significant differences between the upstream and downstream sites, however taxa richness and Shannon’s diversity showed no significant differences, indicating no relative recovery in biodiversity for either periphyton or aquatic macroinvertebrates. Similarly, the upstream and downstream sites showed similar periphyton and aquatic macroinvertebrates assemblages structure, all dominated by pollution tolerant taxa, thus indicating no functional diversity improvement down river; because of improvement in water chemistry downstream sites, it was expected that periphyton and aquatic macroinvertebrates assemblage structure would also improve at these downstream sites.It is possible that the phytoremediation process is outpaced by effluent discharges, given the multiple sources and distance between upstream and downstream mat sites. The study showed phytoremediation potential but the results were not indicated by biological indicators. A replica study conducted on a moderately disturbed river system is recommended to measure the success and recovery of biological indicators and assemblage composition following IAAP species phytoremediation; a moderately disturbed river compared to a largely disturbed river will broaden findings and look at differences for a wider application of phytoremediation.
- Full Text:
- Date Issued: 2020
- Authors: Tshithukhe, Getrude
- Date: 2020
- Subjects: Aquatic weeds -- Biological control -- South Africa -- Eastern Cape , Alien plants -- Biological control -- South Africa -- Eastern Cape , Phytoremediation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167665 , vital:41501
- Description: Pollution effluents in freshwater ecosystems are becoming increasingly ubiquitous as a result of cumulative anthropogenic activities, such as wastewater treatments works, and industrial, agricultural and mining activities. These activities are more noticeable in urban river atchments where there is greater human population densities and industrial developments. The ecological effects of anthropogenic activities on freshwater ecosystems include: excessive deposition of contaminants such as nutrients, pharmaceuticals, microplastics and other chemicals, which change physicochemical properties, causing a decline in aquatic biodiversity. These effects, impact negatively on the resilience of freshwater, making the systems vulnerable to invasion by alien aquatic plants. Ultimately, the loss of local biodiversity associated with the invasive alien aquatic plants (IAAP) results in a loss of some ecosystem goods and services. The Swartkops River system, Eastern Cape Province, drains most of the neighbouring formal and informal settlements, agricultural lands and industries, and hence is exposed to water pollution from human activities along the river catchment. Various water quality assessments are needed to evaluate the extent of pollutants and their impacts on the river ecosystem. Phytoremediation is one approach employed internationally for removing harmful nutrients and chemicals in freshwater ecosystems. Most studies measure the success of phytoremediation through measuring the reduction of contaminants in water or soil chemistry in mesocosm settings, which may not take into account all the important environmental factors that exist in the field. The present study assesses the phytoremediation potential of Pontederia (Eichhornia) crassipes and Salvinia molesta by evaluating water and sediment chemistry, periphyton and aquatic macroinvertebrate community recovery along seven field sites (excluding IAAP species mats sites) located upstream and downstream IAAP species mats on the Swartkops River between April and September 2018. Water and sediment samples were collected once monthly on ten seven field sites, including the IAAP species mat sites. Periphyton and aquatic macroinvertebrates were collected on seven sites, excluding the IAAP mat sites. Pontederia crassipes and S. molesta infestation in Swartkops River showed positive phytoremediation results and improved some water and sediment chemistry in the downstream treatments as compared to upstream treatments. Although there were some fluctuations with some variables, important water and sediment chemistry were reduced downstream. By contrast, biological assessment results did not show any response to the presence of IAAP species and phytoremediation. Periphyton and aquatic macroinvertebrates diversity and community assemblages were more influenced by water quality. Although IAAP species did provide improvement in water and sediments chemistry, multiple effluent point and non-point sources in Swartkops outpaced phytoremediation. Taxa evenness and relative taxa abundance showed significant differences between the upstream and downstream sites, however taxa richness and Shannon’s diversity showed no significant differences, indicating no relative recovery in biodiversity for either periphyton or aquatic macroinvertebrates. Similarly, the upstream and downstream sites showed similar periphyton and aquatic macroinvertebrates assemblages structure, all dominated by pollution tolerant taxa, thus indicating no functional diversity improvement down river; because of improvement in water chemistry downstream sites, it was expected that periphyton and aquatic macroinvertebrates assemblage structure would also improve at these downstream sites.It is possible that the phytoremediation process is outpaced by effluent discharges, given the multiple sources and distance between upstream and downstream mat sites. The study showed phytoremediation potential but the results were not indicated by biological indicators. A replica study conducted on a moderately disturbed river system is recommended to measure the success and recovery of biological indicators and assemblage composition following IAAP species phytoremediation; a moderately disturbed river compared to a largely disturbed river will broaden findings and look at differences for a wider application of phytoremediation.
- Full Text:
- Date Issued: 2020
Assessing sediment particle-size effects on benthic algal colonisation and total carbohydrate production
- Dalu, Tatenda, Cuthbert, Ross N, Chavalala, Tiyisani L, Froneman, P William, Wasserman, Ryan J
- Authors: Dalu, Tatenda , Cuthbert, Ross N , Chavalala, Tiyisani L , Froneman, P William , Wasserman, Ryan J
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/466815 , vital:76789 , https://doi.org/10.1016/j.scitotenv.2019.136348
- Description: Increased sedimentation and siltation associated with anthropogenic environmental change may alter microbial biofilms and the carbohydrates they produce, with potential bottom-up effects in these ecosystems. The present study aimed to examine to what extent carbohydrate (associated with biofilm exopolymer) concentration and benthic algal biomass vary among different sediment types (size-structure categories) using a microcosm experiment conducted over a period of 28 days. Substrate treatment and time had a significant effect on the total chlorophyll-a concentrations, whilst a significant interaction was present in the case of total sediment carbohydrates. Total sediment carbohydrates did not relate significantly to chlorophyll-a concentrations overall, nor for any substrate treatments owing to a non-significant ‘chlorophyll-a × substrate’ interaction term. The diatom community characteristics across sediment sizes were unique for each treatment in our study, with unique dominant diatom taxa compositions within each sediment size class. The finest sediment particle-size (greater than 63 μm) may be the least stable, most likely due to lower binding. We anticipate that the current study findings will lead to a better understanding of how different sediment types due to sedimentation and siltation will impact on primary productivity and the composition of diatom communities in aquatic systems.
- Full Text:
- Date Issued: 2020
- Authors: Dalu, Tatenda , Cuthbert, Ross N , Chavalala, Tiyisani L , Froneman, P William , Wasserman, Ryan J
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/466815 , vital:76789 , https://doi.org/10.1016/j.scitotenv.2019.136348
- Description: Increased sedimentation and siltation associated with anthropogenic environmental change may alter microbial biofilms and the carbohydrates they produce, with potential bottom-up effects in these ecosystems. The present study aimed to examine to what extent carbohydrate (associated with biofilm exopolymer) concentration and benthic algal biomass vary among different sediment types (size-structure categories) using a microcosm experiment conducted over a period of 28 days. Substrate treatment and time had a significant effect on the total chlorophyll-a concentrations, whilst a significant interaction was present in the case of total sediment carbohydrates. Total sediment carbohydrates did not relate significantly to chlorophyll-a concentrations overall, nor for any substrate treatments owing to a non-significant ‘chlorophyll-a × substrate’ interaction term. The diatom community characteristics across sediment sizes were unique for each treatment in our study, with unique dominant diatom taxa compositions within each sediment size class. The finest sediment particle-size (greater than 63 μm) may be the least stable, most likely due to lower binding. We anticipate that the current study findings will lead to a better understanding of how different sediment types due to sedimentation and siltation will impact on primary productivity and the composition of diatom communities in aquatic systems.
- Full Text:
- Date Issued: 2020
Assessing the implementation of long-acting reversible contraceptive implant, Implanon NXT, roll out in East London, Eastern Cape, South Africa.
- Authors: Mdingi, Mildred Mandisa
- Date: 2020
- Subjects: Primary health care
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/18452 , vital:42267
- Description: Background: In 2014, South African Department of Health (SADOH) initiated use of Implanon NXT, a type of implant in addition to long-acting reversible contraceptives available in the country to expand contraceptives options for women of reproductive age. After its introduction, there were reports on early removals and frequent side effects. It is therefore vital to identify how successful the implementation of this method was in particular in East London area. Objectives: The purpose of this study was to evaluate how successful the implementation of Implanon NXT roll out was in East London, Eastern Cape. Additionally, the study also aimed to understand the views health care providers have of the Implanon NXT. Methods: A retrospective crosssectional design using existing data from family planning registers and distribution of questionnaires to Health Care Providers responsible for insertion and removal of the method (HCP). Results: February 2014 to March 2019, 1238 Implanon NXT insertions were done and only 266 removals in one study site. Out of the 266 participants, 67.7% of the participants removed the Implanon for reasons other than ill health (side effects), while the remaining 32.3% had experienced side effects and opted for early Implanon removal. Bleeding was the most common side effect reported by 44 of 266 (16.5%) participants. The health care providers who completed questionnaires for this study were overall confident in providing the Implanon NXT services. Conclusion: Implementation of a new contraceptive method requires clear standardised policies and guidelines on counselling and management of side effects. Findings of this study are reassuring that Implanon NXT had a role to play in prevention of unintended pregnancies. Implementation and rollout in one site reviewed has been demonstrated to be successful. The respondents in this study possesses knowledge about the Implanon NXT.
- Full Text:
- Date Issued: 2020
- Authors: Mdingi, Mildred Mandisa
- Date: 2020
- Subjects: Primary health care
- Language: English
- Type: Thesis , Masters , MPH
- Identifier: http://hdl.handle.net/10353/18452 , vital:42267
- Description: Background: In 2014, South African Department of Health (SADOH) initiated use of Implanon NXT, a type of implant in addition to long-acting reversible contraceptives available in the country to expand contraceptives options for women of reproductive age. After its introduction, there were reports on early removals and frequent side effects. It is therefore vital to identify how successful the implementation of this method was in particular in East London area. Objectives: The purpose of this study was to evaluate how successful the implementation of Implanon NXT roll out was in East London, Eastern Cape. Additionally, the study also aimed to understand the views health care providers have of the Implanon NXT. Methods: A retrospective crosssectional design using existing data from family planning registers and distribution of questionnaires to Health Care Providers responsible for insertion and removal of the method (HCP). Results: February 2014 to March 2019, 1238 Implanon NXT insertions were done and only 266 removals in one study site. Out of the 266 participants, 67.7% of the participants removed the Implanon for reasons other than ill health (side effects), while the remaining 32.3% had experienced side effects and opted for early Implanon removal. Bleeding was the most common side effect reported by 44 of 266 (16.5%) participants. The health care providers who completed questionnaires for this study were overall confident in providing the Implanon NXT services. Conclusion: Implementation of a new contraceptive method requires clear standardised policies and guidelines on counselling and management of side effects. Findings of this study are reassuring that Implanon NXT had a role to play in prevention of unintended pregnancies. Implementation and rollout in one site reviewed has been demonstrated to be successful. The respondents in this study possesses knowledge about the Implanon NXT.
- Full Text:
- Date Issued: 2020
Assessing the Social Sustainability of Wind Energy in the Karoo
- Authors: Hechter, J P
- Date: 2020
- Subjects: Wind power -- South Africa -- Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48378 , vital:40854
- Description: Background: In an ecologically conscious world, the need for sustainable development and the need to produce alternative energy is at the forefront of discussions. South Africa has been witnessing to a surge in wind energy developments in recent years. Although, environmental impacts often enjoy more emphasis, social impacts are equally important. Recently social sustainability was seen as an integral part of sustainable development for the future and can no longer be ignored. Wind energy is pathway towards sustainable development but can have detrimental impacts on social sustainability. On the one hand wind energy is said to impact culture, sense of places and cause unrest in a community, however, on the other hand it is said to be socially sustainable to the point where wind energy is incorporated into local culture and not to mention the employment opportunities it can create. This is particularly important for vulnerable communities found in the Karoo, where unemployment is very high. Purpose/ Aim: The aim of this study was to assess the social sustainability of a wind energy project in the Karoo by constructing a theoretical assessment model designed to produce appropriate and specific social indicators. Methodology: A literature review was undertaken to gain insights into the social sustainability of wind energy which also served as the theoretical backbone for the model and assessment parameters. The assessment model produced 10 indicators which was used as interview schedule with key stakeholders in the study area. A total of 31 qualitative interviews were conducted and produced a good data set. Findings: The results from this study show that here was no significant negative impact reported with regards to social sustainability. The wind developer is committed to the community based on the various social initiative funded by it. Although a definite positive impact and improvement in terms of social sustainability is evident in the area, there is still a long way to go as many outcomes set by the wind developer is yet to achieved.
- Full Text:
- Date Issued: 2020
- Authors: Hechter, J P
- Date: 2020
- Subjects: Wind power -- South Africa -- Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48378 , vital:40854
- Description: Background: In an ecologically conscious world, the need for sustainable development and the need to produce alternative energy is at the forefront of discussions. South Africa has been witnessing to a surge in wind energy developments in recent years. Although, environmental impacts often enjoy more emphasis, social impacts are equally important. Recently social sustainability was seen as an integral part of sustainable development for the future and can no longer be ignored. Wind energy is pathway towards sustainable development but can have detrimental impacts on social sustainability. On the one hand wind energy is said to impact culture, sense of places and cause unrest in a community, however, on the other hand it is said to be socially sustainable to the point where wind energy is incorporated into local culture and not to mention the employment opportunities it can create. This is particularly important for vulnerable communities found in the Karoo, where unemployment is very high. Purpose/ Aim: The aim of this study was to assess the social sustainability of a wind energy project in the Karoo by constructing a theoretical assessment model designed to produce appropriate and specific social indicators. Methodology: A literature review was undertaken to gain insights into the social sustainability of wind energy which also served as the theoretical backbone for the model and assessment parameters. The assessment model produced 10 indicators which was used as interview schedule with key stakeholders in the study area. A total of 31 qualitative interviews were conducted and produced a good data set. Findings: The results from this study show that here was no significant negative impact reported with regards to social sustainability. The wind developer is committed to the community based on the various social initiative funded by it. Although a definite positive impact and improvement in terms of social sustainability is evident in the area, there is still a long way to go as many outcomes set by the wind developer is yet to achieved.
- Full Text:
- Date Issued: 2020
Assessment of taste masking of captopril by ion-exchange resins using electronic gustatory system
- Chikukwa, Mellisa T R, Wesoly, Malgorzata, Korzeniowska, Aleksandra B, Ciosek-Skibinska, Patrycja, Walker, Roderick B, Khamanga, Sandile M M
- Authors: Chikukwa, Mellisa T R , Wesoly, Malgorzata , Korzeniowska, Aleksandra B , Ciosek-Skibinska, Patrycja , Walker, Roderick B , Khamanga, Sandile M M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184710 , vital:44265 , xlink:href="https://doi.org/10.1080/10837450.2019.1687520"
- Description: The objective of the study was to mask the unpleasant taste of captopril (CPT). Taste masking was achieved by complexation of CPT with a basic ion exchange resin, Dowex® 66, using the batch method. Dowex® 66 was used for the adsorption of CPT, and physical and chemical parameters of the CPT resinates complex were evaluated. A central composite design was used to generate the experiments for the manufacture of resinates using different process and formulation variables. In vitro dissolution studies were performed for 2 h in 0.01N HCl (pH 1.6) using USP Apparatus I. The compatibility of CPT and the resin was evaluated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The resinates were evaluated for micromeritic properties and further characterised using FTIR, DSC, and PXRD. Response surface methodology was used to determine the significance of input variables on the CPT content and release. The CPT resin ratio was found to have a significant impact on content of the resinates and on CPT release. The formulations were also studied for taste masking ability by means of an electronic gustatory system – electronic tongue.
- Full Text:
- Date Issued: 2020
- Authors: Chikukwa, Mellisa T R , Wesoly, Malgorzata , Korzeniowska, Aleksandra B , Ciosek-Skibinska, Patrycja , Walker, Roderick B , Khamanga, Sandile M M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184710 , vital:44265 , xlink:href="https://doi.org/10.1080/10837450.2019.1687520"
- Description: The objective of the study was to mask the unpleasant taste of captopril (CPT). Taste masking was achieved by complexation of CPT with a basic ion exchange resin, Dowex® 66, using the batch method. Dowex® 66 was used for the adsorption of CPT, and physical and chemical parameters of the CPT resinates complex were evaluated. A central composite design was used to generate the experiments for the manufacture of resinates using different process and formulation variables. In vitro dissolution studies were performed for 2 h in 0.01N HCl (pH 1.6) using USP Apparatus I. The compatibility of CPT and the resin was evaluated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The resinates were evaluated for micromeritic properties and further characterised using FTIR, DSC, and PXRD. Response surface methodology was used to determine the significance of input variables on the CPT content and release. The CPT resin ratio was found to have a significant impact on content of the resinates and on CPT release. The formulations were also studied for taste masking ability by means of an electronic gustatory system – electronic tongue.
- Full Text:
- Date Issued: 2020
Assessment of the implementation of the citizen centric strategies for social grant service delivery :Chris Hani District
- Authors: Danster, Siyabulela
- Date: 2020
- Subjects: South African Social Security Agency -- South Africa -- Chris Hani District
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46692 , vital:39609
- Description: This study aimed to assess the implementation of citizen centric strategies for social grant service delivery in the Chris Hani District and if SASSA is still living up to its promise. SASSA claims it will always pay the right social grant, to the right person, at the right time and place. This study aimed to understand and assess the different strategies of SASSA towards enhancing citizen experience in delivering social grants. The study’s objective was to assess citizen experience regarding the SASSA social grant payment systems, the social grant application processes, and SASSA communication and advocacy programmes. To conduct this study, a qualitative research methodology was employed. The population sample comprised of SASSA officials in the Chris Hani District. Semi-structured interviews were conducted with SASSA officials. The findings of this study reveal that SASSA did well to improve application turnaround time from 90 days to one day. Even so, payment methods must be improved. The recommendations suggest that SASSA should consider insourcing the function of paying social grants and consider opening the closed pay-points, as beneficiaries are struggling to travel to the remaining opened pay-points. The findings also proposed aligning the SocPen and MIS.
- Full Text:
- Date Issued: 2020
- Authors: Danster, Siyabulela
- Date: 2020
- Subjects: South African Social Security Agency -- South Africa -- Chris Hani District
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46692 , vital:39609
- Description: This study aimed to assess the implementation of citizen centric strategies for social grant service delivery in the Chris Hani District and if SASSA is still living up to its promise. SASSA claims it will always pay the right social grant, to the right person, at the right time and place. This study aimed to understand and assess the different strategies of SASSA towards enhancing citizen experience in delivering social grants. The study’s objective was to assess citizen experience regarding the SASSA social grant payment systems, the social grant application processes, and SASSA communication and advocacy programmes. To conduct this study, a qualitative research methodology was employed. The population sample comprised of SASSA officials in the Chris Hani District. Semi-structured interviews were conducted with SASSA officials. The findings of this study reveal that SASSA did well to improve application turnaround time from 90 days to one day. Even so, payment methods must be improved. The recommendations suggest that SASSA should consider insourcing the function of paying social grants and consider opening the closed pay-points, as beneficiaries are struggling to travel to the remaining opened pay-points. The findings also proposed aligning the SocPen and MIS.
- Full Text:
- Date Issued: 2020
Assessment of the microbial quality of various domestic rainwater harvesting systems and the suitability of a nano based treatment method
- Authors: Malema, Mokaba Shirley
- Date: 2020
- Language: English
- Type: thesis , text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/110218 , vital:33249 , https://dx.doi.org/10.21504/10962/110218
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Chemistry, 2020.
- Full Text: false
- Date Issued: 2020
- Authors: Malema, Mokaba Shirley
- Date: 2020
- Language: English
- Type: thesis , text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/110218 , vital:33249 , https://dx.doi.org/10.21504/10962/110218
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Chemistry, 2020.
- Full Text: false
- Date Issued: 2020
Associations between family history of diseases of lifestyle, lifestyle behaviour and anthropometric nutritional status of pre-school children in ECD centres in the Nelson Mandela Bay Municipality
- Authors: Wilson, Teresa Margaret
- Date: 2020
- Subjects: Nutrition--Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/46344 , vital:39602
- Description: Introduction: Childhood overweight and obesity is an escalating global health issue. In Africa, overweight and obesity prevalence in children has nearly doubled since 2000(World Health Organisation, 2018).TheSANHANES-1 study (2013) identified that overweight and obesity in were most prevalent in urban informal areas of South Africa, with approximately a quarter of the children classified as overweight or obese (Shisana et al., 2013).In the Nelson Mandela Bay Municipality(NMBM), a double burden of disease was identified in the lower socio-economic population (Phekana et al., 2016). This study and others recommended further study into the contributing factors and behaviours which play a role in the development of overweight and obesity in children. These include household dietary intake, family history of lifestyle diseases, as well as the children’s and parental physical activity and sedentary time (Zhang et al.,2016).Aim: The aim of the study was to determine the associations between family history of diseases of lifestyle, lifestyle behaviour and anthropometric nutritional status of pre-school children in NMBM to describe underlying causes of childhood overweight and obesity.Methods: A cross-sectional design, using a quantitative approach, was used for this study(Ethics approval: H18-HEA-DIET-004). The study population included adult parents and/or caregivers of children from urban areas of Nelson Mandela Bay Municipality attending crèches and schools in these areas, in the age group from birth to 96 months (8 years). Randomised cluster sampling of crèches and schools from an existing database of anthropometrical data of children attending these crèches and schools in the area was done and a final sample of n=155obtained. With the assistance of a trained fieldworker, respondents completed a questionnaire detailing the family history of lifestyle diseases, physical activity levels and sedentary screen time behaviours, and a graphical adjusted version of a household dietary diversity questionnaire. Data about children’s activity levels in the preschool/creche environment was collected by the fieldworker by assessing the ECD centres’daily activity schedules. The anthropometric data of the children of the respondents was accessed from an existing database of these measurements. The data was described using means and standard deviations. Inferential statistics determined any existing associations between these underlying influences of childhood obesity.Results: Only 2% (n=3) of the children were underweight and 12% (n=9) were at risk of becoming underweight as classified by WAZ. HAZ scores identified26% (n=40) of the children at risk of becoming stunted, and 6% (n=9) of the children were already stunted. WHZ classified5% (n=8)of the children as overweight and 5% (n=8)as obese. A further 22% (n=34) of the children were at risk of becoming overweight.BMI/age classificationidentified25% (n=38) of the children as overweight and a further 12% (n=19) as obese. Out of the sample, 12%(n=17) of mothers and 8% (n=7) of fathers were categorised as overweight-to-obese according to the SA specific waist circumference(WC)cut-offs. Out of the children, 15% (n=22) have at least one parent who was overweight-to-obese. Traditional WC categories were classified48% (n=67) of the mothers as overweight-to-obese and at high risk for metabolic syndrome. Of all the lifestyle diseases, hypertension was the most prevalent with 29% (n=41) of households having at least one parent with hypertension. Parental physical activity was grossly overestimated, and the results found to be invalid. The Diet Variety and Frequency score resulted in a mean of 65.00 (n=154, SD=27.37) out of a possible 100 for the households in this sample, and junk food was consumed on three to four occasions per day in 32% (n=49) of households. There were no significant associations found between the parents’ variables and underweight children. Statistically small to medium effect associations were found between parental weight (both SA specific and traditional categories) and overweight children (classified by WHZ and BMI/age). Conclusions and recommendations: The prevalence of overweight and obesity among children in the NMBM was high. The only possible underlying cause of childhood overweight and obesity in pre-school children in the NMBM that could be determined by this study was parents’ weight classified by WC. However, it must be reiterated that due to the cross-sectional nature of the study, an association does not immediately mean causation, and the results are not adequate to rule out other underlying factors influencing childhood obesity. It is recommended that the results of the study are used to incentivise the final implementation of all the intervention targets laid out in the Strategic Plan for the Prevention and Control of Obesity in South Africa 2015-2020 in NMB, and for the development of the future obesity strategy after 2020. The results have shown the necessity for future health interventions to be targeted at the family as a unit.
- Full Text:
- Date Issued: 2020
- Authors: Wilson, Teresa Margaret
- Date: 2020
- Subjects: Nutrition--Evaluation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/46344 , vital:39602
- Description: Introduction: Childhood overweight and obesity is an escalating global health issue. In Africa, overweight and obesity prevalence in children has nearly doubled since 2000(World Health Organisation, 2018).TheSANHANES-1 study (2013) identified that overweight and obesity in were most prevalent in urban informal areas of South Africa, with approximately a quarter of the children classified as overweight or obese (Shisana et al., 2013).In the Nelson Mandela Bay Municipality(NMBM), a double burden of disease was identified in the lower socio-economic population (Phekana et al., 2016). This study and others recommended further study into the contributing factors and behaviours which play a role in the development of overweight and obesity in children. These include household dietary intake, family history of lifestyle diseases, as well as the children’s and parental physical activity and sedentary time (Zhang et al.,2016).Aim: The aim of the study was to determine the associations between family history of diseases of lifestyle, lifestyle behaviour and anthropometric nutritional status of pre-school children in NMBM to describe underlying causes of childhood overweight and obesity.Methods: A cross-sectional design, using a quantitative approach, was used for this study(Ethics approval: H18-HEA-DIET-004). The study population included adult parents and/or caregivers of children from urban areas of Nelson Mandela Bay Municipality attending crèches and schools in these areas, in the age group from birth to 96 months (8 years). Randomised cluster sampling of crèches and schools from an existing database of anthropometrical data of children attending these crèches and schools in the area was done and a final sample of n=155obtained. With the assistance of a trained fieldworker, respondents completed a questionnaire detailing the family history of lifestyle diseases, physical activity levels and sedentary screen time behaviours, and a graphical adjusted version of a household dietary diversity questionnaire. Data about children’s activity levels in the preschool/creche environment was collected by the fieldworker by assessing the ECD centres’daily activity schedules. The anthropometric data of the children of the respondents was accessed from an existing database of these measurements. The data was described using means and standard deviations. Inferential statistics determined any existing associations between these underlying influences of childhood obesity.Results: Only 2% (n=3) of the children were underweight and 12% (n=9) were at risk of becoming underweight as classified by WAZ. HAZ scores identified26% (n=40) of the children at risk of becoming stunted, and 6% (n=9) of the children were already stunted. WHZ classified5% (n=8)of the children as overweight and 5% (n=8)as obese. A further 22% (n=34) of the children were at risk of becoming overweight.BMI/age classificationidentified25% (n=38) of the children as overweight and a further 12% (n=19) as obese. Out of the sample, 12%(n=17) of mothers and 8% (n=7) of fathers were categorised as overweight-to-obese according to the SA specific waist circumference(WC)cut-offs. Out of the children, 15% (n=22) have at least one parent who was overweight-to-obese. Traditional WC categories were classified48% (n=67) of the mothers as overweight-to-obese and at high risk for metabolic syndrome. Of all the lifestyle diseases, hypertension was the most prevalent with 29% (n=41) of households having at least one parent with hypertension. Parental physical activity was grossly overestimated, and the results found to be invalid. The Diet Variety and Frequency score resulted in a mean of 65.00 (n=154, SD=27.37) out of a possible 100 for the households in this sample, and junk food was consumed on three to four occasions per day in 32% (n=49) of households. There were no significant associations found between the parents’ variables and underweight children. Statistically small to medium effect associations were found between parental weight (both SA specific and traditional categories) and overweight children (classified by WHZ and BMI/age). Conclusions and recommendations: The prevalence of overweight and obesity among children in the NMBM was high. The only possible underlying cause of childhood overweight and obesity in pre-school children in the NMBM that could be determined by this study was parents’ weight classified by WC. However, it must be reiterated that due to the cross-sectional nature of the study, an association does not immediately mean causation, and the results are not adequate to rule out other underlying factors influencing childhood obesity. It is recommended that the results of the study are used to incentivise the final implementation of all the intervention targets laid out in the Strategic Plan for the Prevention and Control of Obesity in South Africa 2015-2020 in NMB, and for the development of the future obesity strategy after 2020. The results have shown the necessity for future health interventions to be targeted at the family as a unit.
- Full Text:
- Date Issued: 2020