Allosteric pockets and dynamic residue network hubs of falcipain 2 in mutations including those linked to artemisinin resistance
- Okeke, Chiamaka J, Musyoka, Thommas M, Sheik Amamuddy, Olivier, Barozi, Victor, Tastan Bishop, Özlem
- Authors: Okeke, Chiamaka J , Musyoka, Thommas M , Sheik Amamuddy, Olivier , Barozi, Victor , Tastan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/476585 , vital:77939 , xlink:href="https://doi.org/10.1016/j.csbj.2021.10.011"
- Description: Continually emerging resistant strains of malarial parasites to current drugs present challenges. Understanding the underlying resistance mechanisms, especially those linked to allostery is, thus, highly crucial for drug design. This forms the main concern of the paper through a case study of falcipain 2 (FP-2) and its mutations, some of which are linked to artemisinin (ART) drug resistance. Here, we applied a variety of in silico approaches and tools that we developed recently, together with existing computational tools. This included novel essential dynamics and dynamic residue network (DRN) analysis algorithms. We identified six pockets demonstrating dynamic differences in the presence of some mutations. We observed striking allosteric effects in two mutant proteins. In the presence of M245I, a cryptic pocket was detected via a unique mechanism in which Pocket 2 fused with Pocket 6. In the presence of the A353T mutation, which is located at Pocket 2, the pocket became the most rigid among all protein systems analyzed. Pocket 6 was also highly stable in all cases, except in the presence of M245I mutation. The effect of ART linked mutations was more subtle, and the changes were at residue level. Importantly, we identified an allosteric communication path formed by four unique averaged BC hubs going from the mutated residue to the catalytic site and passing through the interface of three identified pockets. Collectively, we established and demonstrated that we have robust tools and a pipeline that can be applicable to the analysis of mutations.
- Full Text:
- Authors: Okeke, Chiamaka J , Musyoka, Thommas M , Sheik Amamuddy, Olivier , Barozi, Victor , Tastan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/476585 , vital:77939 , xlink:href="https://doi.org/10.1016/j.csbj.2021.10.011"
- Description: Continually emerging resistant strains of malarial parasites to current drugs present challenges. Understanding the underlying resistance mechanisms, especially those linked to allostery is, thus, highly crucial for drug design. This forms the main concern of the paper through a case study of falcipain 2 (FP-2) and its mutations, some of which are linked to artemisinin (ART) drug resistance. Here, we applied a variety of in silico approaches and tools that we developed recently, together with existing computational tools. This included novel essential dynamics and dynamic residue network (DRN) analysis algorithms. We identified six pockets demonstrating dynamic differences in the presence of some mutations. We observed striking allosteric effects in two mutant proteins. In the presence of M245I, a cryptic pocket was detected via a unique mechanism in which Pocket 2 fused with Pocket 6. In the presence of the A353T mutation, which is located at Pocket 2, the pocket became the most rigid among all protein systems analyzed. Pocket 6 was also highly stable in all cases, except in the presence of M245I mutation. The effect of ART linked mutations was more subtle, and the changes were at residue level. Importantly, we identified an allosteric communication path formed by four unique averaged BC hubs going from the mutated residue to the catalytic site and passing through the interface of three identified pockets. Collectively, we established and demonstrated that we have robust tools and a pipeline that can be applicable to the analysis of mutations.
- Full Text:
Aluminum corrosion retardation properties of acetamidophenoxy phthalocyanines: Effect of central metal
- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
Amphiphilic axially modified cationic indium-porphyrins linked to hydrophilic magnetic nanoparticles for photodynamic antimicrobial chemotherapy against gram-negative strain; Escherichia coli
- Makolla, Collen L, Mgidlana, Sithi, Nyokong, Tebello
- Authors: Makolla, Collen L , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185024 , vital:44317 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109262"
- Description: In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.
- Full Text:
- Authors: Makolla, Collen L , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185024 , vital:44317 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109262"
- Description: In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.
- Full Text:
An Application to Support end-users of wi-fi Hotspots in the Township of Makhanda
- Buwa, Lubabalo, Shibeshi, Zelalem S, Terzoli, Alfredo
- Authors: Buwa, Lubabalo , Shibeshi, Zelalem S , Terzoli, Alfredo
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429077 , vital:72558 , https://ieeexplore.ieee.org/abstract/document/9514200
- Description: Having access to the Internet is a powerful resource that can change one's life, but connectivity inequality continues to be a significant issue, especially for disadvantaged communities. The usage of Wi-Fi hotspots is becoming very useful for accommodating many people living in underprivileged areas to connect to the Internet. Primarily, these hotspots get deployed in public places like hotels, restaurants, etc. This paper discusses how such a system can be made to work as a solution for disadvantaged communities considering the user base in such communities and adhering to government regulations. The research is developed in collaboration with Khula Tech Solutions ISP that provides wireless Internet services in Makhanda (formally known as Grahamstown). Khula Tech Solutions is starting an initiative of installing Wi-Fi hotspots around the township of Makhanda and needs an application that will support users of the Wi-Fi hotspots. The research's result is a proof-of-concept mobile application developed through iterative and incremental software development techniques and mobile application technologies. With this research, the hope is that it is the beginning of further work for the users to become connected citizens.
- Full Text:
- Authors: Buwa, Lubabalo , Shibeshi, Zelalem S , Terzoli, Alfredo
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429077 , vital:72558 , https://ieeexplore.ieee.org/abstract/document/9514200
- Description: Having access to the Internet is a powerful resource that can change one's life, but connectivity inequality continues to be a significant issue, especially for disadvantaged communities. The usage of Wi-Fi hotspots is becoming very useful for accommodating many people living in underprivileged areas to connect to the Internet. Primarily, these hotspots get deployed in public places like hotels, restaurants, etc. This paper discusses how such a system can be made to work as a solution for disadvantaged communities considering the user base in such communities and adhering to government regulations. The research is developed in collaboration with Khula Tech Solutions ISP that provides wireless Internet services in Makhanda (formally known as Grahamstown). Khula Tech Solutions is starting an initiative of installing Wi-Fi hotspots around the township of Makhanda and needs an application that will support users of the Wi-Fi hotspots. The research's result is a proof-of-concept mobile application developed through iterative and incremental software development techniques and mobile application technologies. With this research, the hope is that it is the beginning of further work for the users to become connected citizens.
- Full Text:
An evaluation of co-management practices: A case of a South African platinum mine management and the local community
- Authors: Matsimela, Tebogo Mapipi
- Date: 2021
- Subjects: Mines and mineral resource -- Management -- South Africa , Mines and mineral resource -- Management -- Social aspects , Mines and mineral resource -- Management -- Moral and ethical aspects , Platinum mines and mining -- Management -- South Africa -- Case studies , Corporate governance -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/171874 , vital:42134
- Description: A vast body of literature reveals the paradigm shift of South Africa’s economy from an agricultural community to an industrial economy. Elbra (2013) illustrated that South African mining host communities viewed that mineral endowments have become a “resource curse” instead of a driver of local economic development for the benefit of the community. To understand the mining and community conflict and their subsequent complexities, the Marikana massacre in August 2012 must be revisited (Bell, 2016). The problems may be broadly summarised as a lack of stakeholder engagement and inclusivity. Studies involving stakeholder management and co-management focused on the identification of stakeholders and their management. The research evaluated the co-management practices between mine management and a local community. It considered the challenges that emanated from the co-management practices. The primary focus of this research has been to evaluate the co-management features between the mine management and the local community and to identify the challenges associated with co-management from a mine management perspective. Furthermore, the research attempted to find effective co-management practices between the mine management and the local community which may be used to improve the partnership. Armitage, Berkes and Doubleplay (2007) recognised that in facilitating effective co-management, the commitment towards fulfilling good governance and accountability was paramount in ensuring that the rights and obligations of both private and public actors were achieved. However, Ran and Qi (2018) acknowledged that such partnerships were not immune to challenges because the poor implementation of co-management features like power-sharing could collapse a co-management partnership. This study aimed to evaluate the current co-management practices from the mine management’s perspective. A literature search revealed the range of co-management features that explained the different use of practices. The features included co-management and power sharing, co-management and institution building, co-management and trust and social capital, co-management as a process, co-management and problem solving, and co-management and governance. The study evaluated the co-management features between the mine management and the local community, identified the current challenges associated with co-management from a mine management perspective and attempted to make recommendations on effective co-management practices between the mine management and a local community. A qualitative case study method was employed. This method allowed the researcher to evaluate multifaceted matters which may have been investigated in the past but not inconsiderable detail (Baxter and Jack, 2008). Data was sampled using purposive sampling. This was because the population sample was chosen according to their roles and responsibilities and their involvement in the co-management between the mine management and the local community. Data was collected through semi-structured interviews and document analyses. The findings of the research were derived from a range of company documents. Thematic analysis was employed to understand the practices of co-management which underpinned the co-management partnership between the mine management and the local community. It was found that there was a positive relationship between the literature study and the response from the mine management. The shared responsibilities emerged out of a dialogue characterised by deliberation and negotiations between the mine management and the stakeholders. Berkes (2009), asserted that co-management bore a resemblance to the process of the sharing of ideas of how responsibilities could be better shared and that it emanated from a process of deliberation and negotiation. Furthermore, if the evolution of the co-management partnership was not managed carefully, it could pose a risk to the partnership itself. It was acknowledged by the research respondents that there were complications involved in having the community as a shareholder in the mine, but equally, the community showed an appreciation of being involved in building a sustainable mine. The model of sustainable partnership emphasised that any viable partnership should adopt this model to achieve a sustainable performance (Thomson and Boutilier, 2011). This research showed that the co-management practices between the mine management and the local community concurred with the findings of Zvarivadza (2018). Trust and transparency between mine management and the community could go a long way in ensuring that the mine fulfilled its legal responsibilities in the local community where the mine is located.
- Full Text:
- Authors: Matsimela, Tebogo Mapipi
- Date: 2021
- Subjects: Mines and mineral resource -- Management -- South Africa , Mines and mineral resource -- Management -- Social aspects , Mines and mineral resource -- Management -- Moral and ethical aspects , Platinum mines and mining -- Management -- South Africa -- Case studies , Corporate governance -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/171874 , vital:42134
- Description: A vast body of literature reveals the paradigm shift of South Africa’s economy from an agricultural community to an industrial economy. Elbra (2013) illustrated that South African mining host communities viewed that mineral endowments have become a “resource curse” instead of a driver of local economic development for the benefit of the community. To understand the mining and community conflict and their subsequent complexities, the Marikana massacre in August 2012 must be revisited (Bell, 2016). The problems may be broadly summarised as a lack of stakeholder engagement and inclusivity. Studies involving stakeholder management and co-management focused on the identification of stakeholders and their management. The research evaluated the co-management practices between mine management and a local community. It considered the challenges that emanated from the co-management practices. The primary focus of this research has been to evaluate the co-management features between the mine management and the local community and to identify the challenges associated with co-management from a mine management perspective. Furthermore, the research attempted to find effective co-management practices between the mine management and the local community which may be used to improve the partnership. Armitage, Berkes and Doubleplay (2007) recognised that in facilitating effective co-management, the commitment towards fulfilling good governance and accountability was paramount in ensuring that the rights and obligations of both private and public actors were achieved. However, Ran and Qi (2018) acknowledged that such partnerships were not immune to challenges because the poor implementation of co-management features like power-sharing could collapse a co-management partnership. This study aimed to evaluate the current co-management practices from the mine management’s perspective. A literature search revealed the range of co-management features that explained the different use of practices. The features included co-management and power sharing, co-management and institution building, co-management and trust and social capital, co-management as a process, co-management and problem solving, and co-management and governance. The study evaluated the co-management features between the mine management and the local community, identified the current challenges associated with co-management from a mine management perspective and attempted to make recommendations on effective co-management practices between the mine management and a local community. A qualitative case study method was employed. This method allowed the researcher to evaluate multifaceted matters which may have been investigated in the past but not inconsiderable detail (Baxter and Jack, 2008). Data was sampled using purposive sampling. This was because the population sample was chosen according to their roles and responsibilities and their involvement in the co-management between the mine management and the local community. Data was collected through semi-structured interviews and document analyses. The findings of the research were derived from a range of company documents. Thematic analysis was employed to understand the practices of co-management which underpinned the co-management partnership between the mine management and the local community. It was found that there was a positive relationship between the literature study and the response from the mine management. The shared responsibilities emerged out of a dialogue characterised by deliberation and negotiations between the mine management and the stakeholders. Berkes (2009), asserted that co-management bore a resemblance to the process of the sharing of ideas of how responsibilities could be better shared and that it emanated from a process of deliberation and negotiation. Furthermore, if the evolution of the co-management partnership was not managed carefully, it could pose a risk to the partnership itself. It was acknowledged by the research respondents that there were complications involved in having the community as a shareholder in the mine, but equally, the community showed an appreciation of being involved in building a sustainable mine. The model of sustainable partnership emphasised that any viable partnership should adopt this model to achieve a sustainable performance (Thomson and Boutilier, 2011). This research showed that the co-management practices between the mine management and the local community concurred with the findings of Zvarivadza (2018). Trust and transparency between mine management and the community could go a long way in ensuring that the mine fulfilled its legal responsibilities in the local community where the mine is located.
- Full Text:
An Evaluation of Machine Learning Methods for Classifying Bot Traffic in Software Defined Networks
- Van Staden, Joshua, Brown, Dane L
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465645 , vital:76628 , xlink:href="https://link.springer.com/chapter/10.1007/978-981-19-7874-6_72"
- Description: Internet security is an ever-expanding field. Cyber-attacks occur very frequently, and so detecting them is an important aspect of preserving services. Machine learning offers a helpful tool with which to detect cyber attacks. However, it is impossible to deploy a machine-learning algorithm to detect attacks in a non-centralized network. Software Defined Networks (SDNs) offer a centralized view of a network, allowing machine learning algorithms to detect malicious activity within a network. The InSDN dataset is a recently-released dataset that contains a set of sniffed packets within a virtual SDN. These sniffed packets correspond to various attacks, including DDoS attacks, Probing and Password-Guessing, among others. This study aims to evaluate various machine learning models against this new dataset. Specifically, we aim to evaluate their classification ability and runtimes when trained on fewer features. The machine learning models tested include a Neural Network, Support Vector Machine, Random Forest, Multilayer Perceptron, Logistic Regression, and K-Nearest Neighbours. Cluster-based algorithms such as the K-Nearest Neighbour and Random Forest proved to be the best performers. Linear-based algorithms such as the Multilayer Perceptron performed the worst. This suggests a good level of clustering in the top few features with little space for linear separability. The reduction of features significantly reduced training time, particularly in the better-performing models.
- Full Text:
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465645 , vital:76628 , xlink:href="https://link.springer.com/chapter/10.1007/978-981-19-7874-6_72"
- Description: Internet security is an ever-expanding field. Cyber-attacks occur very frequently, and so detecting them is an important aspect of preserving services. Machine learning offers a helpful tool with which to detect cyber attacks. However, it is impossible to deploy a machine-learning algorithm to detect attacks in a non-centralized network. Software Defined Networks (SDNs) offer a centralized view of a network, allowing machine learning algorithms to detect malicious activity within a network. The InSDN dataset is a recently-released dataset that contains a set of sniffed packets within a virtual SDN. These sniffed packets correspond to various attacks, including DDoS attacks, Probing and Password-Guessing, among others. This study aims to evaluate various machine learning models against this new dataset. Specifically, we aim to evaluate their classification ability and runtimes when trained on fewer features. The machine learning models tested include a Neural Network, Support Vector Machine, Random Forest, Multilayer Perceptron, Logistic Regression, and K-Nearest Neighbours. Cluster-based algorithms such as the K-Nearest Neighbour and Random Forest proved to be the best performers. Linear-based algorithms such as the Multilayer Perceptron performed the worst. This suggests a good level of clustering in the top few features with little space for linear separability. The reduction of features significantly reduced training time, particularly in the better-performing models.
- Full Text:
An Evaluation of YOLO-Based Algorithms for Hand Detection in the Kitchen
- Van Staden, Joshua, Brown, Dane L
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465134 , vital:76576 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9519307"
- Description: Convolutional Neural Networks have offered an accurate method with which to run object detection on images. Specifically, the YOLO family of object detection algorithms have proven to be relatively fast and accurate. Since its inception, the different variants of this algorithm have been tested on different datasets. In this paper, we evaluate the performances of these algorithms on the recent Epic Kitchens-100 dataset. This dataset provides egocentric footage of people interacting with various objects in the kitchen. Most prominently shown in the footage is an egocentric view of the participants' hands. We aim to use the YOLOv3 algorithm to detect these hands within the footage provided in this dataset. In particular, we examine the YOLOv3 algorithm using two different backbones: MobileNet-lite and VGG16. We trained them on a mixture of samples from the Egohands and Epic Kitchens-100 datasets. In a separate experiment, average precision was measured on an unseen Epic Kitchens-100 subset. We found that the models are relatively simple and lead to lower scores on the Epic Kitchens 100 dataset. This is attributed to the high background noise on the Epic Kitchens 100 dataset. Nonetheless, the VGG16 architecture was found to have a higher Average Precision (AP) and is, therefore, more suited for retrospective analysis. None of the models was suitable for real-time analysis due to complex egocentric data.
- Full Text:
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465134 , vital:76576 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9519307"
- Description: Convolutional Neural Networks have offered an accurate method with which to run object detection on images. Specifically, the YOLO family of object detection algorithms have proven to be relatively fast and accurate. Since its inception, the different variants of this algorithm have been tested on different datasets. In this paper, we evaluate the performances of these algorithms on the recent Epic Kitchens-100 dataset. This dataset provides egocentric footage of people interacting with various objects in the kitchen. Most prominently shown in the footage is an egocentric view of the participants' hands. We aim to use the YOLOv3 algorithm to detect these hands within the footage provided in this dataset. In particular, we examine the YOLOv3 algorithm using two different backbones: MobileNet-lite and VGG16. We trained them on a mixture of samples from the Egohands and Epic Kitchens-100 datasets. In a separate experiment, average precision was measured on an unseen Epic Kitchens-100 subset. We found that the models are relatively simple and lead to lower scores on the Epic Kitchens 100 dataset. This is attributed to the high background noise on the Epic Kitchens 100 dataset. Nonetheless, the VGG16 architecture was found to have a higher Average Precision (AP) and is, therefore, more suited for retrospective analysis. None of the models was suitable for real-time analysis due to complex egocentric data.
- Full Text:
An Examination of the Nexus between Environmental Knowledge and Environmental Learning Processes
- Chitsiga, Christina, Schudel, Ingrid J
- Authors: Chitsiga, Christina , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435086 , vital:73129 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: Previous chapters in this book have discussed the complexity of environmental content (see Schudel and Lotz-Sisitka, Chapter 2; Isaacs and Olvitt, Chapter 4) and Chapter 8 (Schudel) has highlighted the significance and key elements of active and critical approaches to learning. The primary purpose of this chapter is to draw these two approaches together; that is, to explore the nexus of environmental content and environmental learning processes.
- Full Text:
- Authors: Chitsiga, Christina , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435086 , vital:73129 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: Previous chapters in this book have discussed the complexity of environmental content (see Schudel and Lotz-Sisitka, Chapter 2; Isaacs and Olvitt, Chapter 4) and Chapter 8 (Schudel) has highlighted the significance and key elements of active and critical approaches to learning. The primary purpose of this chapter is to draw these two approaches together; that is, to explore the nexus of environmental content and environmental learning processes.
- Full Text:
An Exploration of what Grade 7 Natural Sciences Teachers Know, Believe and Say about Biodiversity and the Teaching of Biodiversity
- Isaacs, Dorelle, Olvitt, Lausanne L
- Authors: Isaacs, Dorelle , Olvitt, Lausanne L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435153 , vital:73134 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: This chapter shares the findings of a small-scale qualitative research project that investigated what three Grade 7 Natural Sciences teachers know, believe and say about biodiversity (Isaacs 2016). The study was sparked by the researcher’s interest in environmental learning and the importance of school curricula in preparing children to take care of their local and global environments. Biodiversity refers to Earth’s rich variety of plants and animals. It has been described as ‘the complex web of life’that includes diversity at genetic, species and ecosystem levels (Gurr et al. 2012: 4). The concept came to prominence in 1992 when the United Nations’ Convention on Biological Diversity defined biological diversity as ‘the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems’(United Nations 1992: Article 2).
- Full Text:
- Authors: Isaacs, Dorelle , Olvitt, Lausanne L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435153 , vital:73134 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: This chapter shares the findings of a small-scale qualitative research project that investigated what three Grade 7 Natural Sciences teachers know, believe and say about biodiversity (Isaacs 2016). The study was sparked by the researcher’s interest in environmental learning and the importance of school curricula in preparing children to take care of their local and global environments. Biodiversity refers to Earth’s rich variety of plants and animals. It has been described as ‘the complex web of life’that includes diversity at genetic, species and ecosystem levels (Gurr et al. 2012: 4). The concept came to prominence in 1992 when the United Nations’ Convention on Biological Diversity defined biological diversity as ‘the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems’(United Nations 1992: Article 2).
- Full Text:
An exploratory case study on the barriers, challenges and benefits of sustainability reporting by small and medium enterprises (SMEs) in South Africa
- Authors: Mhlope, Veliswa
- Date: 2021
- Subjects: Small business -- South Africa -- Case studies , Sustainable development reporting -- South Africa -- Case studies , Social responsibility of business , Environmental responsibility -- South Africa , Environmental reporting -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/172018 , vital:42149
- Description: SMEs in South Africa and other developing countries have been slow to take up sustainability reporting. This qualitative study is aimed to study the challenges and barriers faced by SMEs, together with the potential benefits for SMEs participating in this type of reporting. It also makes recommendations about how SMEs can participate in and benefit from sustainability reporting. The study shows that indeed there are several challenges in terms of getting involved in sustainability reporting for SMEs. On the other hand, the research finds that the SMEs who are already participating in sustainability reporting can show the benefits of engaging in sustainability reporting and that these benefits far outweigh the challenges. The participating SMEs are also able to show that they have attained a competitive advantage as a result of engaging in sustainability reporting. If, however, sustainability reporting is to become entrenched into SMEs, a few changes need to take place to address challenges such as lack of information about sustainability reporting and its benefits, lack of regulations and more importantly, lack of awareness about sustainable development. As the South African government begins to respond to issues such as climate change, skills development and good governance, it will become necessary for them to introduce regulations to manage this risk. It is also highly possible that in the next few years, reporting will become a regulatory requirement that SMEs will be forced to comply with to continue to do business. The SMEs who are already practising sustainability practices will benefit from being first movers. Those SMEs who start sooner rather than later will already have the internal resources and capabilities to take advantage of the legislative environment. They will have a head start over their rivals in terms of gaining competitive advantage.
- Full Text:
- Authors: Mhlope, Veliswa
- Date: 2021
- Subjects: Small business -- South Africa -- Case studies , Sustainable development reporting -- South Africa -- Case studies , Social responsibility of business , Environmental responsibility -- South Africa , Environmental reporting -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/172018 , vital:42149
- Description: SMEs in South Africa and other developing countries have been slow to take up sustainability reporting. This qualitative study is aimed to study the challenges and barriers faced by SMEs, together with the potential benefits for SMEs participating in this type of reporting. It also makes recommendations about how SMEs can participate in and benefit from sustainability reporting. The study shows that indeed there are several challenges in terms of getting involved in sustainability reporting for SMEs. On the other hand, the research finds that the SMEs who are already participating in sustainability reporting can show the benefits of engaging in sustainability reporting and that these benefits far outweigh the challenges. The participating SMEs are also able to show that they have attained a competitive advantage as a result of engaging in sustainability reporting. If, however, sustainability reporting is to become entrenched into SMEs, a few changes need to take place to address challenges such as lack of information about sustainability reporting and its benefits, lack of regulations and more importantly, lack of awareness about sustainable development. As the South African government begins to respond to issues such as climate change, skills development and good governance, it will become necessary for them to introduce regulations to manage this risk. It is also highly possible that in the next few years, reporting will become a regulatory requirement that SMEs will be forced to comply with to continue to do business. The SMEs who are already practising sustainability practices will benefit from being first movers. Those SMEs who start sooner rather than later will already have the internal resources and capabilities to take advantage of the legislative environment. They will have a head start over their rivals in terms of gaining competitive advantage.
- Full Text:
An exploratory study of psychologists’ perceptions of the phenomenon currently understood as ‘borderline personality disorder’
- Authors: Daya, Lekha
- Date: 2021
- Subjects: Borderline personality disorder , Psychologists -- Attitudes -- South Africa , Diagnostic and statistical manual of mental disorders
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/171139 , vital:42023
- Description: The phenomenon currently understood as ‘borderline personality disorder’ (BPD) has been complex and multifaceted since its inception. Previous studies have focused on the validity of The Diagnostic and Statistical Manual of Mental Disorders (DSM) conceptualisation of BPD, aetiologies of BPD, the psychologies of persons diagnosed with BPD, and the gendered nature of BPD. This study aimed to specifically explore South African practising psychologists’ perceptions of BPD. Through thematic analysis from a constructivist, post-modern paradigm, this study aimed to explore the perceptions and experiences of practising psychologists on BPD, as well as the usefulness of the DSM in working with BPD in a non-western society such as South Africa (SA). The study sampled two Counselling and two Clinical psychologists practising in the South African context, with exposure to and experience in working with BPD. Collectively, results in this study identified psychologists’ perceptions of shortcomings in the usefulness of the DSM’s approach to categorising phenomena associated with BPD, and brought attention to a need for further research and attention into the role of psychologists’ in the construction of BPD. This study seeks to represent psychologists’ practical experiences and perceptions, in an attempt to add contextually relevant findings on the DSM’s construction of BPD, and to contribute to challenging the stigma and misunderstanding associated with BPD. Specific practice implications and recommendations for future research are discussed within.
- Full Text:
- Authors: Daya, Lekha
- Date: 2021
- Subjects: Borderline personality disorder , Psychologists -- Attitudes -- South Africa , Diagnostic and statistical manual of mental disorders
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/171139 , vital:42023
- Description: The phenomenon currently understood as ‘borderline personality disorder’ (BPD) has been complex and multifaceted since its inception. Previous studies have focused on the validity of The Diagnostic and Statistical Manual of Mental Disorders (DSM) conceptualisation of BPD, aetiologies of BPD, the psychologies of persons diagnosed with BPD, and the gendered nature of BPD. This study aimed to specifically explore South African practising psychologists’ perceptions of BPD. Through thematic analysis from a constructivist, post-modern paradigm, this study aimed to explore the perceptions and experiences of practising psychologists on BPD, as well as the usefulness of the DSM in working with BPD in a non-western society such as South Africa (SA). The study sampled two Counselling and two Clinical psychologists practising in the South African context, with exposure to and experience in working with BPD. Collectively, results in this study identified psychologists’ perceptions of shortcomings in the usefulness of the DSM’s approach to categorising phenomena associated with BPD, and brought attention to a need for further research and attention into the role of psychologists’ in the construction of BPD. This study seeks to represent psychologists’ practical experiences and perceptions, in an attempt to add contextually relevant findings on the DSM’s construction of BPD, and to contribute to challenging the stigma and misunderstanding associated with BPD. Specific practice implications and recommendations for future research are discussed within.
- Full Text:
An introduction to the fourth decadal review of biological control of invasive alien plants in South Africa (2011–2020)
- Paterson, Iain D, den Breeyen, Alana, Martin, Grant D, Olckers, Tamryn
- Authors: Paterson, Iain D , den Breeyen, Alana , Martin, Grant D , Olckers, Tamryn
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/413387 , vital:71031 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a2"
- Description: This special issue is the fourth decadal review of biological control of invasive alien plants (biocontrol of weeds) in South Africa, following those published in 1991, 1999 and 2011. Including this introduction, there are 24 papers covering the weed biocontrol programmes, or important developments in the science and practice, from the period 2011-2020. Seventy-two target weed species are covered, including 25 species on which projects were initiated during the past decade. Developments in regulations, mass-rearing and implementation, and community engagement are also reviewed. An updated catalogue of agents released, rejected and under consideration is presented and reflects the most recent methods of quantifying success in weed biocontrol. Key events over the last decade include the hosting of the XIV International Symposium on Biological Control of Weeds to celebrate 100 years of weed biocontrol in South Africa, as well as the establishment of the Centre for Biological Control at Rhodes University. The science and practice of weed biocontrol has expanded significantly in the past decade, with growth in the number of researchers and practitioners, increased funding, and an increased number of scholarly outputs. Unlike many other countries in the world, South Africa has largely avoided constraints due to restrictive and risk averse legislation and bureaucracy, and has continued to release new biocontrol agents at a similar rate to that in previous years. Much of the success of weed biocontrol in South Africa is due to the sustained and increasing support of the Natural Resource Management Programme of the Department of Forestry, Fisheries and the Environment (Working for Water Programme). However, gaps in funding, where no funds are available for months at a time, are a major concern as the weed biocontrol community loses human capital in these periods, and research programmes suffer significant set-backs. Weed biocontrol is an essential component of South Africa’s strategy to reduce the negative impacts of invasive alien plants and has contributed significantly towards the protection of the country’s ecosystems, indigenous biodiversity, water security, agricultural productivity, and society in general. If the trend of increasing support for weed biocontrol in South Africa continues, we can expect that the benefits for the country at large will increase substantially in the future.
- Full Text:
- Authors: Paterson, Iain D , den Breeyen, Alana , Martin, Grant D , Olckers, Tamryn
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/413387 , vital:71031 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a2"
- Description: This special issue is the fourth decadal review of biological control of invasive alien plants (biocontrol of weeds) in South Africa, following those published in 1991, 1999 and 2011. Including this introduction, there are 24 papers covering the weed biocontrol programmes, or important developments in the science and practice, from the period 2011-2020. Seventy-two target weed species are covered, including 25 species on which projects were initiated during the past decade. Developments in regulations, mass-rearing and implementation, and community engagement are also reviewed. An updated catalogue of agents released, rejected and under consideration is presented and reflects the most recent methods of quantifying success in weed biocontrol. Key events over the last decade include the hosting of the XIV International Symposium on Biological Control of Weeds to celebrate 100 years of weed biocontrol in South Africa, as well as the establishment of the Centre for Biological Control at Rhodes University. The science and practice of weed biocontrol has expanded significantly in the past decade, with growth in the number of researchers and practitioners, increased funding, and an increased number of scholarly outputs. Unlike many other countries in the world, South Africa has largely avoided constraints due to restrictive and risk averse legislation and bureaucracy, and has continued to release new biocontrol agents at a similar rate to that in previous years. Much of the success of weed biocontrol in South Africa is due to the sustained and increasing support of the Natural Resource Management Programme of the Department of Forestry, Fisheries and the Environment (Working for Water Programme). However, gaps in funding, where no funds are available for months at a time, are a major concern as the weed biocontrol community loses human capital in these periods, and research programmes suffer significant set-backs. Weed biocontrol is an essential component of South Africa’s strategy to reduce the negative impacts of invasive alien plants and has contributed significantly towards the protection of the country’s ecosystems, indigenous biodiversity, water security, agricultural productivity, and society in general. If the trend of increasing support for weed biocontrol in South Africa continues, we can expect that the benefits for the country at large will increase substantially in the future.
- Full Text:
An investigation into the mediation of the representation of gender roles in God of women : a critical discourse analysis of pedagogic practices in selected Namibian schools
- Nghikefelwa, Josephine Mwasheka
- Authors: Nghikefelwa, Josephine Mwasheka
- Date: 2021
- Subjects: Nyati, Sifiso. God of women , Stereotypes (Social psychology) in literature , Women in literature , English literature -- Study and teaching (Secondary) -- Namibia , Women's rights in literature , Women's rights -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172389 , vital:42195 , 10.21504/10962/172389
- Description: This is a qualitative study designed to investigate the role of pedagogical practices in the mediation of stereotypical gender representations in the drama God of Women by Sifiso Nyathi (1998). This drama is one of the literature setworks for Grade 9 English Second Language learners in Namibian Secondary schools. Fairclough’s (2012) Critical Discourse Analysis was used as a research design, as well as the conceptual and analytical framework. The analysis of this drama by teachers during the teaching and learning process, pedagogic practices they employ, learners’ engagement in classroom activities, and the nature of comments that teachers write on students’ assignment, based on God of Women, formed part of the unit of analysis. The study explored teachers’ pedagogical practices during English Literature teaching to gain insight into whether and how teachers shape learners’ engagement with literature to promote critical thinking. Focus on the mediation process (‘teacher talks around the text’) concerned a close analysis of teachers’ engagement with the text during lessons. Semi-structured interviews, classroom observation and documentary evidence were used to generate data. The research site and study participants were purposively sampled.
- Full Text:
- Authors: Nghikefelwa, Josephine Mwasheka
- Date: 2021
- Subjects: Nyati, Sifiso. God of women , Stereotypes (Social psychology) in literature , Women in literature , English literature -- Study and teaching (Secondary) -- Namibia , Women's rights in literature , Women's rights -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172389 , vital:42195 , 10.21504/10962/172389
- Description: This is a qualitative study designed to investigate the role of pedagogical practices in the mediation of stereotypical gender representations in the drama God of Women by Sifiso Nyathi (1998). This drama is one of the literature setworks for Grade 9 English Second Language learners in Namibian Secondary schools. Fairclough’s (2012) Critical Discourse Analysis was used as a research design, as well as the conceptual and analytical framework. The analysis of this drama by teachers during the teaching and learning process, pedagogic practices they employ, learners’ engagement in classroom activities, and the nature of comments that teachers write on students’ assignment, based on God of Women, formed part of the unit of analysis. The study explored teachers’ pedagogical practices during English Literature teaching to gain insight into whether and how teachers shape learners’ engagement with literature to promote critical thinking. Focus on the mediation process (‘teacher talks around the text’) concerned a close analysis of teachers’ engagement with the text during lessons. Semi-structured interviews, classroom observation and documentary evidence were used to generate data. The research site and study participants were purposively sampled.
- Full Text:
An online information security Aaareness model: the disclosure of personal data
- Authors: Parker, Heather Joubert
- Date: 2021
- Subjects: Social media -- Psychological aspects , Social media -- Psychological aspects -- South Africa , Human behavior , Disclosure of information -- Psychological aspects -- Case studies , Personal information management -- Psychological aspects -- Case studies , Data protection -- Psychologial aspects -- Case studies
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/172329 , vital:42189
- Description: Social media has revolutionized the way people send and receive information by creating a new level of interconnected communication. However, the use of the Internet and social media brings about various ways in which a user’s personal data can be put at risk. This study aims to investigate what drives the disclosure of personal information online and whether an increase in awareness of the value of personal information motivates users to safeguard their information. Fourteen university students participated in a mixed-methods experiment, where they completed a questionnaire before and after being shown the data stored about them by online platforms to determine if changes occur in their intention to disclose. Following completing the initial questionnaire, the participant viewed the personal data stored about them by Facebook, Google, and Instagram. Other online tools such as Social Profile Checker, Facebook View As, and HaveIBeenPawned were used to see the information publicly available about each participant. Together these findings were discussed in a semi-structured interview to determine the influence of attitudes, subjective norms, and awareness on the cost-benefit analysis users conduct when disclosing information online. Overall, the findings indicate that users are able to disregard their concerns due to a resigned and apathetic attitude towards privacy. Furthermore, subjective norms enhanced by FOMO further allow users to overlook potential risks to their information in order to avoid social isolation and sanction. Alternatively, an increased awareness of the personal value of information and having experienced a previous privacy violation encourage the protection of information and limited disclosure. Thus, this study provides insight into privacy and information disclosure on social media in South Africa. It reveals more insight into the cost-benefit analysis users conduct by combining the Theory of Planned Behaviour with the Privacy Calculus Model, as well as the antecedent factors of Trust in the Social Media Provider, FOMO, and Personal Valuation of Information.
- Full Text:
- Authors: Parker, Heather Joubert
- Date: 2021
- Subjects: Social media -- Psychological aspects , Social media -- Psychological aspects -- South Africa , Human behavior , Disclosure of information -- Psychological aspects -- Case studies , Personal information management -- Psychological aspects -- Case studies , Data protection -- Psychologial aspects -- Case studies
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/172329 , vital:42189
- Description: Social media has revolutionized the way people send and receive information by creating a new level of interconnected communication. However, the use of the Internet and social media brings about various ways in which a user’s personal data can be put at risk. This study aims to investigate what drives the disclosure of personal information online and whether an increase in awareness of the value of personal information motivates users to safeguard their information. Fourteen university students participated in a mixed-methods experiment, where they completed a questionnaire before and after being shown the data stored about them by online platforms to determine if changes occur in their intention to disclose. Following completing the initial questionnaire, the participant viewed the personal data stored about them by Facebook, Google, and Instagram. Other online tools such as Social Profile Checker, Facebook View As, and HaveIBeenPawned were used to see the information publicly available about each participant. Together these findings were discussed in a semi-structured interview to determine the influence of attitudes, subjective norms, and awareness on the cost-benefit analysis users conduct when disclosing information online. Overall, the findings indicate that users are able to disregard their concerns due to a resigned and apathetic attitude towards privacy. Furthermore, subjective norms enhanced by FOMO further allow users to overlook potential risks to their information in order to avoid social isolation and sanction. Alternatively, an increased awareness of the personal value of information and having experienced a previous privacy violation encourage the protection of information and limited disclosure. Thus, this study provides insight into privacy and information disclosure on social media in South Africa. It reveals more insight into the cost-benefit analysis users conduct by combining the Theory of Planned Behaviour with the Privacy Calculus Model, as well as the antecedent factors of Trust in the Social Media Provider, FOMO, and Personal Valuation of Information.
- Full Text:
Another isiXhosa Monolingual Dictionary: A Critical Analysis of the Shuters IsiChazi-magama SesiXhosa
- Authors: Nkomo, Dion
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/468095 , vital:77007 , https://doi.org/10.5788/31-1-1658
- Description: This article offers a critical analysis and evaluation of the Shuters IsiChazi-magama SesiXhosa, the second monolingual dictionary in the history of isiXhosa. The analysis draws theoretical and methodological insights from dictionary criticism as a domain of metalexicography and analyses the dictionary in view of existing dictionaries in the language, especially the first monolingual dictionary published under the auspices of the IsiXhosa National Lexicography Unit (XNLU) a decade earlier. Concise paraphrases of meaning are identified as the major strength of this dictionary when compared to its XNLU predecessor. However, inconsistent provision of microstructural entries, an imbalanced macrostructure and a non-integrated front matter reduce the user-friendliness of the dictionary. Nevertheless, another dictionary in isiXhosa produced without the involvement of a National Lexicography Unit is welcome towards the intellectualisation of African languages.
- Full Text:
- Authors: Nkomo, Dion
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/468095 , vital:77007 , https://doi.org/10.5788/31-1-1658
- Description: This article offers a critical analysis and evaluation of the Shuters IsiChazi-magama SesiXhosa, the second monolingual dictionary in the history of isiXhosa. The analysis draws theoretical and methodological insights from dictionary criticism as a domain of metalexicography and analyses the dictionary in view of existing dictionaries in the language, especially the first monolingual dictionary published under the auspices of the IsiXhosa National Lexicography Unit (XNLU) a decade earlier. Concise paraphrases of meaning are identified as the major strength of this dictionary when compared to its XNLU predecessor. However, inconsistent provision of microstructural entries, an imbalanced macrostructure and a non-integrated front matter reduce the user-friendliness of the dictionary. Nevertheless, another dictionary in isiXhosa produced without the involvement of a National Lexicography Unit is welcome towards the intellectualisation of African languages.
- Full Text:
Antiviral drug discovery: preparing for the next pandemic
- Adamson, Catherine S, Chibale, Kelly, Goss, Rebecca J M, Jaspars, Marcel, Newman, David J, Dorrington, Rosemary A
- Authors: Adamson, Catherine S , Chibale, Kelly , Goss, Rebecca J M , Jaspars, Marcel , Newman, David J , Dorrington, Rosemary A
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177499 , vital:42827 , DOI: 10.1039/d0cs01118e
- Description: Clinically approved antiviral drugs are currently available for only 10 of the more than 220 viruses known to infect humans. The SARS-CoV-2 outbreak has exposed the critical need for compounds that can be rapidly mobilised for the treatment of re-emerging or emerging viral diseases, while vaccine development is underway. We review the current status of antiviral therapies focusing on RNA viruses, highlighting strategies for antiviral drug discovery and discuss the challenges, solutions and options to accelerate drug discovery efforts.
- Full Text:
- Authors: Adamson, Catherine S , Chibale, Kelly , Goss, Rebecca J M , Jaspars, Marcel , Newman, David J , Dorrington, Rosemary A
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177499 , vital:42827 , DOI: 10.1039/d0cs01118e
- Description: Clinically approved antiviral drugs are currently available for only 10 of the more than 220 viruses known to infect humans. The SARS-CoV-2 outbreak has exposed the critical need for compounds that can be rapidly mobilised for the treatment of re-emerging or emerging viral diseases, while vaccine development is underway. We review the current status of antiviral therapies focusing on RNA viruses, highlighting strategies for antiviral drug discovery and discuss the challenges, solutions and options to accelerate drug discovery efforts.
- Full Text:
Arylquinolinecarboxamides: Synthesis, in vitro and in silico studies against Mycobacterium tuberculosis
- Bokosi, Fostino R B, Beteck, Richard M, Jordaan, Audrey, Seldon, Ronnett, Warner, Digby F, Tshiwawa, Tendamudzimu, Lobb, Kevin A, Khanye, Setshaba D
- Authors: Bokosi, Fostino R B , Beteck, Richard M , Jordaan, Audrey , Seldon, Ronnett , Warner, Digby F , Tshiwawa, Tendamudzimu , Lobb, Kevin A , Khanye, Setshaba D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451064 , vital:75015 , xlink:href="https://doi.org/10.1002/jhet.4340"
- Description: A series of fourteen 6-substituted-2-(methoxyquinolin-3-yl) methyl)-N-(pyridin-3-ylmethyl) benzamides was prepared from commercially available anilines infive simple and convenient synthetic steps. The structures of all new productswere confirmed by routine spectroscopic methods: IR,1Hand13 CNMR,andHRMS (electrospray ionization). The resulting arylquinolinecarboxamides weresubjected to biological screening assay forin vitroinhibitory activity againstMyco-bacterium tuberculosis (Mtb) H37Rv strain. Several compounds exhibited modestantitubercular activity with compounds8–11,15and19exhibiting MIC90valuesin the range of 32–85μM. The antitubercular data suggested that inhibition ofMtbcan be imparted by the introduction of a non-polar substituent on C-6 of thequinoline scaffold. Further, to understandthepossiblemodeofactionoftheseries, the reported compounds and bedaquiline were subjected toin silicodock-ing studies againstMtbATPase to determine their potential to interfere with themycobacterial adenosine triphosphate (ATP) synthase. The results showed thatthese compounds have the potential toserve as antimycobacterial agents.In silicoADME pharmacokinetic prediction results showed the ability of thesearylquinolinecarcboxamides to be absorbed, distributed, metabolized andexcreted efficiently.
- Full Text:
- Authors: Bokosi, Fostino R B , Beteck, Richard M , Jordaan, Audrey , Seldon, Ronnett , Warner, Digby F , Tshiwawa, Tendamudzimu , Lobb, Kevin A , Khanye, Setshaba D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451064 , vital:75015 , xlink:href="https://doi.org/10.1002/jhet.4340"
- Description: A series of fourteen 6-substituted-2-(methoxyquinolin-3-yl) methyl)-N-(pyridin-3-ylmethyl) benzamides was prepared from commercially available anilines infive simple and convenient synthetic steps. The structures of all new productswere confirmed by routine spectroscopic methods: IR,1Hand13 CNMR,andHRMS (electrospray ionization). The resulting arylquinolinecarboxamides weresubjected to biological screening assay forin vitroinhibitory activity againstMyco-bacterium tuberculosis (Mtb) H37Rv strain. Several compounds exhibited modestantitubercular activity with compounds8–11,15and19exhibiting MIC90valuesin the range of 32–85μM. The antitubercular data suggested that inhibition ofMtbcan be imparted by the introduction of a non-polar substituent on C-6 of thequinoline scaffold. Further, to understandthepossiblemodeofactionoftheseries, the reported compounds and bedaquiline were subjected toin silicodock-ing studies againstMtbATPase to determine their potential to interfere with themycobacterial adenosine triphosphate (ATP) synthase. The results showed thatthese compounds have the potential toserve as antimycobacterial agents.In silicoADME pharmacokinetic prediction results showed the ability of thesearylquinolinecarcboxamides to be absorbed, distributed, metabolized andexcreted efficiently.
- Full Text:
Assisting Learners to Take Up Agency in Problem-Solving Activities
- Lambrechts, Therese, O’Donoghue, Rob B, Schudel, Ingrid J
- Authors: Lambrechts, Therese , O’Donoghue, Rob B , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435099 , vital:73130 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: The study was informed by an expansion of the ‘design research’ reported by McKenny and Reeves (2012) and it developed as a collaborative design process similar to that described by Voogt, Laferriere, Breuleux, Itow, Hickey and McKenny (2015). Voogt et al. approached design research as a successive and developing process of formative work by participants working together to design and assess a learning programme. In our case the design work was undertaken within a course-supported process of ESD design innovation among participating teachers and subject advisors.
- Full Text:
- Authors: Lambrechts, Therese , O’Donoghue, Rob B , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435099 , vital:73130 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: The study was informed by an expansion of the ‘design research’ reported by McKenny and Reeves (2012) and it developed as a collaborative design process similar to that described by Voogt, Laferriere, Breuleux, Itow, Hickey and McKenny (2015). Voogt et al. approached design research as a successive and developing process of formative work by participants working together to design and assess a learning programme. In our case the design work was undertaken within a course-supported process of ESD design innovation among participating teachers and subject advisors.
- Full Text:
Asymmetric price transmission: an empirical analysis of the relationship between UG-2 chrome ore, charge chrome, nickel and Chinese domestic 304 stainless steel cold rolled coil
- Authors: Le Roux, Simon Petrus
- Date: 2021
- Subjects: Pricing , Chromium ores -- Prices -- South Africa , Nickel -- Prices -- South Africa , Austenitic stainless steel-- Prices -- China , Steel -- Prices -- South Africa , Non-Linear Autoregressive Distributive Lag (NARDL)
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/171336 , vital:42049
- Description: The goal of this study was to determine whether asymmetric price transmission (APT) exists between the prices of South African UG-2 Chrome ore, Charge Chrome, Nickel and Chinese Domestic 304 Stainless steel Cold Rolled Coil prices. Monthly time series data for the period January 2009 to July 2019 was analysed. The Non-Linear Autoregressive Distributive Lag (NARDL) model was applied to test for the presence of price asymmetry between the four variables. Firstly, it was observed that the four variables are cointegrated in the long-run. Secondly, no evidence of price asymmetry was found to be present within the Stainless steel supply chain. The reason for this is most likely due to the extremely close-knit and highly concentrated nature of this industry at each level within the supply chain. The industry can be very opaque to external observers even though the distribution of pricing information is very efficient for participants within the industry.
- Full Text:
- Authors: Le Roux, Simon Petrus
- Date: 2021
- Subjects: Pricing , Chromium ores -- Prices -- South Africa , Nickel -- Prices -- South Africa , Austenitic stainless steel-- Prices -- China , Steel -- Prices -- South Africa , Non-Linear Autoregressive Distributive Lag (NARDL)
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/171336 , vital:42049
- Description: The goal of this study was to determine whether asymmetric price transmission (APT) exists between the prices of South African UG-2 Chrome ore, Charge Chrome, Nickel and Chinese Domestic 304 Stainless steel Cold Rolled Coil prices. Monthly time series data for the period January 2009 to July 2019 was analysed. The Non-Linear Autoregressive Distributive Lag (NARDL) model was applied to test for the presence of price asymmetry between the four variables. Firstly, it was observed that the four variables are cointegrated in the long-run. Secondly, no evidence of price asymmetry was found to be present within the Stainless steel supply chain. The reason for this is most likely due to the extremely close-knit and highly concentrated nature of this industry at each level within the supply chain. The industry can be very opaque to external observers even though the distribution of pricing information is very efficient for participants within the industry.
- Full Text:
Asymmetrical zinc (II) phthalocyanines cobalt tungstate nanomaterial conjugates for photodegradation of methylene blue
- Mgidlana, Sithi, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184991 , vital:44314 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113421"
- Description: Herein, we present syntheses of three asymmetrical zinc(II) phthalocyanine (ZnPc) complexes and hydrothermal synthesis of cobalt tungstate nanoparticles. The ZnPc derivatives were covalently linked to cobalt tungstate nanoparticles. Photophysical and photochemical behaviour of Pcs and nanoconjugates were investigated. The nanoconjugates generated higher triplet quantum yield and singlet oxygen quantum yield than the ZnPcs alone. Furthermore, in this paper photocatalytic efficiencies of ZnPc complexes and nanoconjugates were investigated for the degradation of methylene blue and higher photocatalytic behaviour was observed for the conjugates. The kinetic model was used to study photocatalytic behaviour of all the prepared photocatalysts.
- Full Text:
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184991 , vital:44314 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113421"
- Description: Herein, we present syntheses of three asymmetrical zinc(II) phthalocyanine (ZnPc) complexes and hydrothermal synthesis of cobalt tungstate nanoparticles. The ZnPc derivatives were covalently linked to cobalt tungstate nanoparticles. Photophysical and photochemical behaviour of Pcs and nanoconjugates were investigated. The nanoconjugates generated higher triplet quantum yield and singlet oxygen quantum yield than the ZnPcs alone. Furthermore, in this paper photocatalytic efficiencies of ZnPc complexes and nanoconjugates were investigated for the degradation of methylene blue and higher photocatalytic behaviour was observed for the conjugates. The kinetic model was used to study photocatalytic behaviour of all the prepared photocatalysts.
- Full Text: