Shrub Detection in High-Resolution Imagery: A Comparative Study of Two Deep Learning Approaches
- James, Katherine M F, Bradshaw, Karen L
- Authors: James, Katherine M F , Bradshaw, Karen L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/440326 , vital:73766 , ISBN 9783030955021 , https://doi.org/10.1007/978-3-030-95502-1_41
- Description: A common task in high-resolution remotely-sensed aerial imagery is the detection of particular target plant species for various ecological and agricultural applications. Although traditionally object-based image analysis approaches have been the most popular method for this task, deep learning approaches such as image patch-based convolutional neural networks (CNNs) have been seen to outperform these older approaches. To a lesser extent, fully convolutional networks (FCNs) that allow for semantic segmentation of images, have also begun to be used in the broader literature. This study investigates patch-based CNNs and FCN-based segmentation for shrub detection, targeting a particular invasive shrub genus. The results show that while a patch-based CNN demonstrates strong performance on ideal image patches, the FCN outperforms this approach on real-world proposed image patches with a 52% higher object-level precision and comparable recall. This indicates that FCN-based segmentation approaches are a promising alternative to patch-based approaches, with the added advantage of not requiring any hand-tuning of a patch proposal algorithm.
- Full Text:
- Authors: James, Katherine M F , Bradshaw, Karen L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/440326 , vital:73766 , ISBN 9783030955021 , https://doi.org/10.1007/978-3-030-95502-1_41
- Description: A common task in high-resolution remotely-sensed aerial imagery is the detection of particular target plant species for various ecological and agricultural applications. Although traditionally object-based image analysis approaches have been the most popular method for this task, deep learning approaches such as image patch-based convolutional neural networks (CNNs) have been seen to outperform these older approaches. To a lesser extent, fully convolutional networks (FCNs) that allow for semantic segmentation of images, have also begun to be used in the broader literature. This study investigates patch-based CNNs and FCN-based segmentation for shrub detection, targeting a particular invasive shrub genus. The results show that while a patch-based CNN demonstrates strong performance on ideal image patches, the FCN outperforms this approach on real-world proposed image patches with a 52% higher object-level precision and comparable recall. This indicates that FCN-based segmentation approaches are a promising alternative to patch-based approaches, with the added advantage of not requiring any hand-tuning of a patch proposal algorithm.
- Full Text:
Situating the diversity of Southern African environmental education scholarship within a global conversation at a critical juncture on Earth
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389869 , vital:68491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/247386"
- Description: ¬The collection of papers in Volume 38 in many ways mirrors the diversity of research methodologies and teaching approaches in the contemporary eld of Environmental and Sustainability Education. ¬ e seven papers remind us that, whilst environmental educators and researchers are largely in agreement over the nature and causes of the social-ecological problems that we face in sub-Saharan Africa, there is less certainty around what types of educational approaches and pedagogies are adequate to help resolve them. ¬ e papers in this volume either o er pedagogical innovations that may strengthen teaching and learning for sustainable futures, or they provide insights into the social, cultural and economic contexts in which such teaching and learning occurs.
- Full Text:
- Authors: Olvitt, Lausanne L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389869 , vital:68491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/247386"
- Description: ¬The collection of papers in Volume 38 in many ways mirrors the diversity of research methodologies and teaching approaches in the contemporary eld of Environmental and Sustainability Education. ¬ e seven papers remind us that, whilst environmental educators and researchers are largely in agreement over the nature and causes of the social-ecological problems that we face in sub-Saharan Africa, there is less certainty around what types of educational approaches and pedagogies are adequate to help resolve them. ¬ e papers in this volume either o er pedagogical innovations that may strengthen teaching and learning for sustainable futures, or they provide insights into the social, cultural and economic contexts in which such teaching and learning occurs.
- Full Text:
Slipknot or Crystallographic Error: A Computational Analysis of the Plasmodium falciparum DHFR Structural Folds
- Tata, Rolland B, Alsulami, Ali F, Sheik Amamuddy, Olivier, Blundell, Tom L, Tastan Bishop, Özlem
- Authors: Tata, Rolland B , Alsulami, Ali F , Sheik Amamuddy, Olivier , Blundell, Tom L , Tastan Bishop, Özlem
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/476115 , vital:77883 , https://doi.org/10.3390/ijms23031514
- Description: The presence of protein structures with atypical folds in the Protein Data Bank (PDB) is rare and may result from naturally occurring knots or crystallographic errors. Proper characterisation of such folds is imperative to understanding the basis of naturally existing knots and correcting crystallographic errors. If left uncorrected, such errors can frustrate downstream experiments that depend on the structures containing them. An atypical fold has been identified in P. falciparum dihydrofolate reductase (PfDHFR) between residues 20–51 (loop 1) and residues 191–205 (loop 2). This enzyme is key to drug discovery efforts in the parasite, necessitating a thorough characterisation of these folds. Using multiple sequence alignments (MSA), a unique insert was identified in loop 1 that exacerbates the appearance of the atypical fold-giving it a slipknot-like topology. However, PfDHFR has not been deposited in the knotted proteins database, and processing its structure failed to identify any knots within its folds. The application of protein homology modelling and molecular dynamics simulations on the DHFR domain of P. falciparum and those of two other organisms (E. coli and M. tuberculosis) that were used as molecular replacement templates in solving the PfDHFR structure revealed plausible unentangled or open conformations of these loops. These results will serve as guides for crystallographic experiments to provide further insights into the atypical folds identified.
- Full Text:
- Authors: Tata, Rolland B , Alsulami, Ali F , Sheik Amamuddy, Olivier , Blundell, Tom L , Tastan Bishop, Özlem
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/476115 , vital:77883 , https://doi.org/10.3390/ijms23031514
- Description: The presence of protein structures with atypical folds in the Protein Data Bank (PDB) is rare and may result from naturally occurring knots or crystallographic errors. Proper characterisation of such folds is imperative to understanding the basis of naturally existing knots and correcting crystallographic errors. If left uncorrected, such errors can frustrate downstream experiments that depend on the structures containing them. An atypical fold has been identified in P. falciparum dihydrofolate reductase (PfDHFR) between residues 20–51 (loop 1) and residues 191–205 (loop 2). This enzyme is key to drug discovery efforts in the parasite, necessitating a thorough characterisation of these folds. Using multiple sequence alignments (MSA), a unique insert was identified in loop 1 that exacerbates the appearance of the atypical fold-giving it a slipknot-like topology. However, PfDHFR has not been deposited in the knotted proteins database, and processing its structure failed to identify any knots within its folds. The application of protein homology modelling and molecular dynamics simulations on the DHFR domain of P. falciparum and those of two other organisms (E. coli and M. tuberculosis) that were used as molecular replacement templates in solving the PfDHFR structure revealed plausible unentangled or open conformations of these loops. These results will serve as guides for crystallographic experiments to provide further insights into the atypical folds identified.
- Full Text:
Small but strong: Socioeconomic and ecological resilience of a small European fishing community affected by a submarine volcanic eruption
- De la Cruz-Modino, Raquel, Piñeiro-Corbeira, Cristina, Gutiérrez-Barroso, Josué, González-Cruz, Carla, Barreiro, Rodolfo, Batista-Medina, José A, Pascual-Fernández, José, González, José A, Santana-Talavera, Agustín, Aswani, Shankar
- Authors: De la Cruz-Modino, Raquel , Piñeiro-Corbeira, Cristina , Gutiérrez-Barroso, Josué , González-Cruz, Carla , Barreiro, Rodolfo , Batista-Medina, José A , Pascual-Fernández, José , González, José A , Santana-Talavera, Agustín , Aswani, Shankar
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391397 , vital:68648 , xlink:href="https://doi.org/10.1016/j.ocecoaman.2022.106124"
- Description: Small-scale coastal fishing communities are facing many new challenges, such as rapid ecological changes created by anthropogenic and natural events like earthquakes or volcanic eruptions. This paper explores how a coastal population has responded to such an event and highlights the diverse coping strategies used to tackle it. This research was conducted on the island of El Hierro (Spain), where a submarine volcanic eruption occurred in 2011, affecting a multiple-use Marine Protected Area (MPA) and the nearby fishing community of La Restinga. Our study illustrates how the local population coped with this situation by combining multiple monetary and non-monetary activities (e.g., informal exchanges) as well as the role of institutions in increasing local resilience by supporting fishers' demands and allowing their participation in the decision-making process in the immediate wake of a catastrophic event. Local families also exploited various natural resources in and near the MPA, thus ensuring access to crucial marine resources and continued recreational/cultural services. The results suggest that collective action played a key role in the recovery process after the eruption, creating some advantages for different local groups despite the hazardous nature of the event.
- Full Text:
- Authors: De la Cruz-Modino, Raquel , Piñeiro-Corbeira, Cristina , Gutiérrez-Barroso, Josué , González-Cruz, Carla , Barreiro, Rodolfo , Batista-Medina, José A , Pascual-Fernández, José , González, José A , Santana-Talavera, Agustín , Aswani, Shankar
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391397 , vital:68648 , xlink:href="https://doi.org/10.1016/j.ocecoaman.2022.106124"
- Description: Small-scale coastal fishing communities are facing many new challenges, such as rapid ecological changes created by anthropogenic and natural events like earthquakes or volcanic eruptions. This paper explores how a coastal population has responded to such an event and highlights the diverse coping strategies used to tackle it. This research was conducted on the island of El Hierro (Spain), where a submarine volcanic eruption occurred in 2011, affecting a multiple-use Marine Protected Area (MPA) and the nearby fishing community of La Restinga. Our study illustrates how the local population coped with this situation by combining multiple monetary and non-monetary activities (e.g., informal exchanges) as well as the role of institutions in increasing local resilience by supporting fishers' demands and allowing their participation in the decision-making process in the immediate wake of a catastrophic event. Local families also exploited various natural resources in and near the MPA, thus ensuring access to crucial marine resources and continued recreational/cultural services. The results suggest that collective action played a key role in the recovery process after the eruption, creating some advantages for different local groups despite the hazardous nature of the event.
- Full Text:
Sn (IV) porphyrin-biotin decorated nitrogen doped graphene quantum dots nanohybrids for photodynamic therapy
- Magaela, N Bridged, Matshitse, Refilwe, Balaji, Babu, Managa, Muthumuni, Prinsloo, Earl, Nyokong, Tebello
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Balaji, Babu , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230018 , vital:49733 , xlink:href="https://doi.org/10.1016/j.poly.2021.115624"
- Description: Photodynamic therapy (PDT) is a minimally invasive therapeutic procedure for cancer treatment. This study focuses on the synthesis, photophysicochemical properties, and PDT activity of Sn (IV) porphyrin (2), when linked to biotin decorated nitrogen doped graphene quantum dots (B-NGQDs). The porphyrin complex 2 was conjugated through an ester bond to B-NGQDs to form 2-B-NGQDs. Singlet oxygen quantum yield increased for 2 when linked to B-NGQDs to form 2-B-NQGDs. The dark toxicity and photodynamic therapy studies were conducted for 2, NGQDs and their conjugates using MCF-7 breast cancer cells. The cell viability for dark toxicity of all the compounds was above 90%, and 2-B-NGQDs showed high PDT activity at a concentration of 40 µg/mL with cell viability of 22%.
- Full Text:
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Balaji, Babu , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230018 , vital:49733 , xlink:href="https://doi.org/10.1016/j.poly.2021.115624"
- Description: Photodynamic therapy (PDT) is a minimally invasive therapeutic procedure for cancer treatment. This study focuses on the synthesis, photophysicochemical properties, and PDT activity of Sn (IV) porphyrin (2), when linked to biotin decorated nitrogen doped graphene quantum dots (B-NGQDs). The porphyrin complex 2 was conjugated through an ester bond to B-NGQDs to form 2-B-NGQDs. Singlet oxygen quantum yield increased for 2 when linked to B-NGQDs to form 2-B-NQGDs. The dark toxicity and photodynamic therapy studies were conducted for 2, NGQDs and their conjugates using MCF-7 breast cancer cells. The cell viability for dark toxicity of all the compounds was above 90%, and 2-B-NGQDs showed high PDT activity at a concentration of 40 µg/mL with cell viability of 22%.
- Full Text:
Social contracts and informal workers in the global south
- Alfers, Laura C, Chen, Martha A, Plagerson, Sophie
- Authors: Alfers, Laura C , Chen, Martha A , Plagerson, Sophie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/478205 , vital:78164 , ISBN 9781839108068 , https://doi.org/10.4337/9781839108068
- Description: This is an open access work distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Unported (This is an open access work distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Unported (https://creativecommons. org/licenses/by-nc-nd/4.0/). Users can redistribute the work for non-commercial purposes, as long as it is passed along unchanged and in whole, as detailed in the License. Edward Elgar Publishing Ltd must be clearly credited as the owner of the original work. Any translation or adaptation of the original content requires the written authorization of Edward Elgar Publishing Ltd.). Users can redistribute the work for non-commercial purposes, as long as it is passed along unchanged and in whole, as detailed in the License. Edward Elgar Publishing Ltd must be clearly credited as the rights holder for publication of the original work. Any translation or adaptation of the original content requires the written authorization of Edward Elgar Publishing Ltd.
- Full Text:
- Authors: Alfers, Laura C , Chen, Martha A , Plagerson, Sophie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/478205 , vital:78164 , ISBN 9781839108068 , https://doi.org/10.4337/9781839108068
- Description: This is an open access work distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Unported (This is an open access work distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Unported (https://creativecommons. org/licenses/by-nc-nd/4.0/). Users can redistribute the work for non-commercial purposes, as long as it is passed along unchanged and in whole, as detailed in the License. Edward Elgar Publishing Ltd must be clearly credited as the owner of the original work. Any translation or adaptation of the original content requires the written authorization of Edward Elgar Publishing Ltd.). Users can redistribute the work for non-commercial purposes, as long as it is passed along unchanged and in whole, as detailed in the License. Edward Elgar Publishing Ltd must be clearly credited as the rights holder for publication of the original work. Any translation or adaptation of the original content requires the written authorization of Edward Elgar Publishing Ltd.
- Full Text:
Social, ethical and cultural responsibility as core values for doctoral researchers in the 21st century
- Chiappa, Roxana, Cantini, Danielle, Karakasoglu, Yasemin, Manathunga, Catherine, Peters, Christian, Scholz, Beate, Yarar, Betul
- Authors: Chiappa, Roxana , Cantini, Danielle , Karakasoglu, Yasemin , Manathunga, Catherine , Peters, Christian , Scholz, Beate , Yarar, Betul
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434515 , vital:73072 , ISBN 9781800080218 , 10.14324/111.9781800080188
- Description: With the dramatic events of a global pandemic, the beginning of the twenty-first century’s third decade has underlined that the world is facing universal challenges. The worldwide crisis scenario that COVID-19 has produced makes us realise that science and research do not function and operate in an independent sphere hidden within the proverbial ivory tower, but, on the contrary, are closely linked to the social, cultural and political systems they reside in. This creates opportunities and great tensions and, while exploring those, Chapter 9 connects to and builds on most of the dimensions described in the previous sections of the book. We refer primarily to Hannover Recommendations 1 and 7: 1. Establish a global joint value system for doctoral education based on an ecology of knowledges which recognises and seeks to overcome existing inequalities in the access to doctoral education and the provision of knowledge. 7. The pivotal goal of doctoral education must be and remain the development of original, responsible, and ethical thinkers, and the generation of new and original ideas and knowledge.
- Full Text:
- Authors: Chiappa, Roxana , Cantini, Danielle , Karakasoglu, Yasemin , Manathunga, Catherine , Peters, Christian , Scholz, Beate , Yarar, Betul
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434515 , vital:73072 , ISBN 9781800080218 , 10.14324/111.9781800080188
- Description: With the dramatic events of a global pandemic, the beginning of the twenty-first century’s third decade has underlined that the world is facing universal challenges. The worldwide crisis scenario that COVID-19 has produced makes us realise that science and research do not function and operate in an independent sphere hidden within the proverbial ivory tower, but, on the contrary, are closely linked to the social, cultural and political systems they reside in. This creates opportunities and great tensions and, while exploring those, Chapter 9 connects to and builds on most of the dimensions described in the previous sections of the book. We refer primarily to Hannover Recommendations 1 and 7: 1. Establish a global joint value system for doctoral education based on an ecology of knowledges which recognises and seeks to overcome existing inequalities in the access to doctoral education and the provision of knowledge. 7. The pivotal goal of doctoral education must be and remain the development of original, responsible, and ethical thinkers, and the generation of new and original ideas and knowledge.
- Full Text:
Social-ecological change: insights from the Southern African Program on Ecosystem Change and Society
- Biggs, Reinette, Clements, Hayley S, Cumming, Graeme S, Cundill, Georgina, de Vos, Alta, Hamann, Maike, Luvuno, Linda, Roux, Dirk J, Selomane, Odirilwe, Blanchard, Ryan, Cockburn, Jessica J, Dziba, Luthando E, Esler, Karen J, Fabricius, Christo, Henriksson, Rebecka, Kotschy, Karen, Lindborg, Regina, Masterson, Vanessa A, Nel, Jeanne L, O'Farrell, Patrick, Palmer, Carolyn G, Pereira, Laura, Pollard, Sharon, Preiser, Rika, Scholes, Robert J, Shackleton, Charlie M, Shackleton, Sheona E, Sitas, Nadia, Slingsby, Jasper A, Spierenburg, Maria, Tengö, Maria, Reyers, Belinda
- Authors: Biggs, Reinette , Clements, Hayley S , Cumming, Graeme S , Cundill, Georgina , de Vos, Alta , Hamann, Maike , Luvuno, Linda , Roux, Dirk J , Selomane, Odirilwe , Blanchard, Ryan , Cockburn, Jessica J , Dziba, Luthando E , Esler, Karen J , Fabricius, Christo , Henriksson, Rebecka , Kotschy, Karen , Lindborg, Regina , Masterson, Vanessa A , Nel, Jeanne L , O'Farrell, Patrick , Palmer, Carolyn G , Pereira, Laura , Pollard, Sharon , Preiser, Rika , Scholes, Robert J , Shackleton, Charlie M , Shackleton, Sheona E , Sitas, Nadia , Slingsby, Jasper A , Spierenburg, Maria , Tengö, Maria , Reyers, Belinda
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399817 , vital:69561 , xlink:href="https://doi.org/10.1080/26395916.2022.2097478"
- Description: Social-ecological systems (SES) research has emerged as an important area of sustainability science, informing and supporting pressing issues of transformation towards more sustainable, just and equitable futures. To date, much SES research has been done in or from the Global North, where the challenges and contexts for supporting sustainability transformations are substantially different from the Global South. This paper synthesises emerging insights on SES dynamics that can inform actions and advance research to support sustainability transformations specifically in the southern African context. The paper draws on work linked to members of the Southern African Program on Ecosystem Change and Society (SAPECS), a leading SES research network in the region, synthesizing key insights with respect to the five core themes of SAPECS: (i) transdisciplinary and engaged research, (ii) ecosystem services and human well-being, (iii) governance institutions and management practices, (iv) spatial relationships and cross-scale connections, and (v) regime shifts, traps and transformations. For each theme, we focus on insights that are particularly novel, interesting or important in the southern African context, and reflect on key research gaps and emerging frontiers for SES research in the region going forward. Such place-based insights are important for understanding the variation in SES dynamics around the world, and are crucial for informing a context-sensitive global agenda to foster sustainability transformations at local to global scales.
- Full Text:
Social-ecological change: insights from the Southern African Program on Ecosystem Change and Society
- Authors: Biggs, Reinette , Clements, Hayley S , Cumming, Graeme S , Cundill, Georgina , de Vos, Alta , Hamann, Maike , Luvuno, Linda , Roux, Dirk J , Selomane, Odirilwe , Blanchard, Ryan , Cockburn, Jessica J , Dziba, Luthando E , Esler, Karen J , Fabricius, Christo , Henriksson, Rebecka , Kotschy, Karen , Lindborg, Regina , Masterson, Vanessa A , Nel, Jeanne L , O'Farrell, Patrick , Palmer, Carolyn G , Pereira, Laura , Pollard, Sharon , Preiser, Rika , Scholes, Robert J , Shackleton, Charlie M , Shackleton, Sheona E , Sitas, Nadia , Slingsby, Jasper A , Spierenburg, Maria , Tengö, Maria , Reyers, Belinda
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399817 , vital:69561 , xlink:href="https://doi.org/10.1080/26395916.2022.2097478"
- Description: Social-ecological systems (SES) research has emerged as an important area of sustainability science, informing and supporting pressing issues of transformation towards more sustainable, just and equitable futures. To date, much SES research has been done in or from the Global North, where the challenges and contexts for supporting sustainability transformations are substantially different from the Global South. This paper synthesises emerging insights on SES dynamics that can inform actions and advance research to support sustainability transformations specifically in the southern African context. The paper draws on work linked to members of the Southern African Program on Ecosystem Change and Society (SAPECS), a leading SES research network in the region, synthesizing key insights with respect to the five core themes of SAPECS: (i) transdisciplinary and engaged research, (ii) ecosystem services and human well-being, (iii) governance institutions and management practices, (iv) spatial relationships and cross-scale connections, and (v) regime shifts, traps and transformations. For each theme, we focus on insights that are particularly novel, interesting or important in the southern African context, and reflect on key research gaps and emerging frontiers for SES research in the region going forward. Such place-based insights are important for understanding the variation in SES dynamics around the world, and are crucial for informing a context-sensitive global agenda to foster sustainability transformations at local to global scales.
- Full Text:
Socio-ecological Justice Informed Curriculum: Inquiry Transformative Potentials of Critical Water Pedagogy
- Authors: James, Anna
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436159 , vital:73231 , ISBN 978-3-030-84510-0 , https://doi.org/10.1007/978-3-030-84510-0_5
- Description: This paper brings water education, critical pedagogy, and environmental learning into dialogue for the purposes of ar-ticulating some tensions and openings toward a critical envi-ronmental pedagogy that is asked of us in contexts of the Global South. Against this backdrop, I present a pedagogical framework for a socio-ecological school’s audit which seeks to bring to life the possibility of merging environmental and social movement knowledge. Drawing on the threads of transformative potential from literature on water education projects situated in South Africa, I offer a framework for en-gaging with water as socio-ecological phenomena that re-spond to multiple experiences and the urgency of knowing and shifting our structural relationship to water.
- Full Text:
- Authors: James, Anna
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436159 , vital:73231 , ISBN 978-3-030-84510-0 , https://doi.org/10.1007/978-3-030-84510-0_5
- Description: This paper brings water education, critical pedagogy, and environmental learning into dialogue for the purposes of ar-ticulating some tensions and openings toward a critical envi-ronmental pedagogy that is asked of us in contexts of the Global South. Against this backdrop, I present a pedagogical framework for a socio-ecological school’s audit which seeks to bring to life the possibility of merging environmental and social movement knowledge. Drawing on the threads of transformative potential from literature on water education projects situated in South Africa, I offer a framework for en-gaging with water as socio-ecological phenomena that re-spond to multiple experiences and the urgency of knowing and shifting our structural relationship to water.
- Full Text:
Solvent promoted tautomerism in thione-containing tetraazatricyclics: evidence from 1H NMR spectroscopy and transition state studies
- Odame, Felix, Tshentu, Zenixole R, Lobb, Kevin A
- Authors: Odame, Felix , Tshentu, Zenixole R , Lobb, Kevin A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453198 , vital:75230 , xlink:href="https://link.springer.com/article/10.1007/s00894-022-05204-w"
- Description: Tautomerism in the nitro substituted thione-containing traazatricyclics has been investigated. Evidence from 1 H NMR indicating the existence of the tautomers has been augmented with computational studies providing evidence of the stability or otherwise of these tautomers. The role of water and DMSO in the formation of the tautomers has been explained. The role of the nitro group in assisting in the formation of the tautomers has been discussed.
- Full Text:
- Authors: Odame, Felix , Tshentu, Zenixole R , Lobb, Kevin A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453198 , vital:75230 , xlink:href="https://link.springer.com/article/10.1007/s00894-022-05204-w"
- Description: Tautomerism in the nitro substituted thione-containing traazatricyclics has been investigated. Evidence from 1 H NMR indicating the existence of the tautomers has been augmented with computational studies providing evidence of the stability or otherwise of these tautomers. The role of water and DMSO in the formation of the tautomers has been explained. The role of the nitro group in assisting in the formation of the tautomers has been discussed.
- Full Text:
South African Lagerstätte reveals middle Permian Gondwanan lakeshore ecosystem in exquisite detail
- Prevec, Rosemary, Nel, André, O.Day, Michael, Muir, Robert, Matiwane, Aviwe, Kirkaldy, Abigail P, Moyo, Sydney, Staniczek, Arnold, Cariglino, Bárbara, Maseko, Zolile, Kom, Nokuthula, Rubidge, Bruce S, Garrouste, Romain, Holland, Alexandra J, Barber-James, Helen M
- Authors: Prevec, Rosemary , Nel, André , O.Day, Michael , Muir, Robert , Matiwane, Aviwe , Kirkaldy, Abigail P , Moyo, Sydney , Staniczek, Arnold , Cariglino, Bárbara , Maseko, Zolile , Kom, Nokuthula , Rubidge, Bruce S , Garrouste, Romain , Holland, Alexandra J , Barber-James, Helen M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426673 , vital:72378 , xlink:href="https://doi.org/10.1038/s42003-022-04132-y"
- Description: Continental ecosystems of the middle Permian Period (273–259 million years ago) are poorly understood. In South Africa, the vertebrate fossil record is well documented for this time interval, but the plants and insects are virtually unknown, and are rare globally. This scarcity of data has hampered studies of the evolution and diversification of life, and has precluded detailed reconstructions and analyses of ecosystems of this critical period in Earth’s history. Here we introduce a new locality in the southern Karoo Basin that is producing exceptionally well-preserved and abundant fossils of novel freshwater and terrestrial insects, arachnids, and plants. Within a robust regional geochronological, geological and biostratigraphic context, this Konservat- and Konzentrat-Lagerstätte offers a unique opportunity for the study and reconstruction of a southern Gondwanan deltaic ecosystem that thrived 266–268 million years ago, and will serve as a high-resolution ecological baseline towards a better understanding of Permian extinction events.
- Full Text:
- Authors: Prevec, Rosemary , Nel, André , O.Day, Michael , Muir, Robert , Matiwane, Aviwe , Kirkaldy, Abigail P , Moyo, Sydney , Staniczek, Arnold , Cariglino, Bárbara , Maseko, Zolile , Kom, Nokuthula , Rubidge, Bruce S , Garrouste, Romain , Holland, Alexandra J , Barber-James, Helen M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426673 , vital:72378 , xlink:href="https://doi.org/10.1038/s42003-022-04132-y"
- Description: Continental ecosystems of the middle Permian Period (273–259 million years ago) are poorly understood. In South Africa, the vertebrate fossil record is well documented for this time interval, but the plants and insects are virtually unknown, and are rare globally. This scarcity of data has hampered studies of the evolution and diversification of life, and has precluded detailed reconstructions and analyses of ecosystems of this critical period in Earth’s history. Here we introduce a new locality in the southern Karoo Basin that is producing exceptionally well-preserved and abundant fossils of novel freshwater and terrestrial insects, arachnids, and plants. Within a robust regional geochronological, geological and biostratigraphic context, this Konservat- and Konzentrat-Lagerstätte offers a unique opportunity for the study and reconstruction of a southern Gondwanan deltaic ecosystem that thrived 266–268 million years ago, and will serve as a high-resolution ecological baseline towards a better understanding of Permian extinction events.
- Full Text:
Stereotyping, Exploitation, and Appropriation of African Traditional Religious Beliefs: The Case of Nyaminyami, Water Spirit, among the Batonga People of Northwestern Zimbabwe, 1860s–1960s
- Authors: Matanzima, Joshua
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426543 , vital:72361 , xlink:href="https://doi.org/10.5325/jafrireli.10.1.0072"
- Description: This article examines the forms of knowledge that existed between Africans and Europeans regarding local indigenous religious beliefs, focusing particularly on the case of Nyaminyami, a water spirit that is part of the belief systems prevalent among some BaTonga people of northwestern Zimbabwe. The article briefly outlines the “traditional” BaTonga beliefs and practices relating to Nyaminyami, which were diametrically opposed to those of the Europeans. It then scrutinizes the ways the beliefs have been exploited and appropriated by different interest groups and races from the 1860s to the 1960s. The BaTonga people, who held strong beliefs in Nyaminyami, and European colonists used the idea of Nyaminyami for different social, political, and environmental agendas prior to, during, and after resettlement. Nyaminyami played changing sociocultural and economic functions for the BaTonga people over time. They revered Nyaminyami as their river god in the nineteenth and twentieth centuries; they also appropriated the beliefs by rallying behind the river god for protection from their displacement in 1958 following the construction of the Kariba Dam on the Zambezi River. Nyaminyami was also appropriated by European interest groups who used the idea of Nyaminyami to cast Africa as the “dark continent” and to stereotype the BaTonga people as primitive. This article relies on data obtained through a reading of European explorers' texts and by gathering oral traditions among the BaTonga and Shangwe.
- Full Text:
- Authors: Matanzima, Joshua
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426543 , vital:72361 , xlink:href="https://doi.org/10.5325/jafrireli.10.1.0072"
- Description: This article examines the forms of knowledge that existed between Africans and Europeans regarding local indigenous religious beliefs, focusing particularly on the case of Nyaminyami, a water spirit that is part of the belief systems prevalent among some BaTonga people of northwestern Zimbabwe. The article briefly outlines the “traditional” BaTonga beliefs and practices relating to Nyaminyami, which were diametrically opposed to those of the Europeans. It then scrutinizes the ways the beliefs have been exploited and appropriated by different interest groups and races from the 1860s to the 1960s. The BaTonga people, who held strong beliefs in Nyaminyami, and European colonists used the idea of Nyaminyami for different social, political, and environmental agendas prior to, during, and after resettlement. Nyaminyami played changing sociocultural and economic functions for the BaTonga people over time. They revered Nyaminyami as their river god in the nineteenth and twentieth centuries; they also appropriated the beliefs by rallying behind the river god for protection from their displacement in 1958 following the construction of the Kariba Dam on the Zambezi River. Nyaminyami was also appropriated by European interest groups who used the idea of Nyaminyami to cast Africa as the “dark continent” and to stereotype the BaTonga people as primitive. This article relies on data obtained through a reading of European explorers' texts and by gathering oral traditions among the BaTonga and Shangwe.
- Full Text:
Structural modification of RhIIItriarylcorroles for enhanced electrocatalyzed hydrogen evolution reactions
- Zhu, Weihua, Li, Lihua, Wang, Yu, Mack, John, Dingiswayo, Somila, Nyokong, Tebello, Liang, Xu
- Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
- Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
- Full Text:
- Authors: Zhu, Weihua , Li, Lihua , Wang, Yu , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229933 , vital:49724 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.110046"
- Description: A series of A3 type RhIIItriarylcorroles 2a-c with different meso-substituents with differing electron-donating and withdrawing properties and two A2B type RhIIItriarylcorroles 4a-b with meso-methylthiophenyls at the B position have been prepared and characterized. An analysis of structure-property relationships of 2a-c and 4a-b has been carried out by comparing the optical spectroscopy and electrochemistry of the dyes to trends predicted in DFT and TD-DFT calculations. Rational structural modification strategies that enhance the suitability of 2a-c for use as highly efficient catalysts for hydrogen evolution reactions on glassy carbon electrodes coated with 2a-c/reduced graphene oxide composites and of 4a-b in surface-modified Au electrodes are explored.
- Full Text:
Suitably Strange: Re-imagining learning, scholar-activism, and justice
- Authors: McGarry, Dylan K
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/371005 , vital:66402 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
- Description: Using artworks emergent from my career as a pracademic and scholar activist, I attempt to share a ‘tactile theory’ of being and doing, that refer mainly to response-abilities (i.e., abilities to respond in accountable ways) in scholar activist educational sociology. I aim to make visible (and tactile) the sometimes-invisible qualities and practices needed for navigating the eroded and dying ecological relations of our generation, as well as warming up and making pliable the heteronormative, capitalist, patriarchal and anthropocentric conventions that are associated with it. In order to warm and sculpt these normative conventions, I argue for the need for ‘suitably strange’ practice. I present six images and associated prose that aim to optimally disrupt these conventions, towards generative rethinking and embodying learning, scholar activism and justice, and from which I explore a tactile theory, an example and related response-ability for each. I end with a reflection of how these suitably strange artefacts can help us develop a new concept of proactive-cognitive justice or ‘justness’.
- Full Text:
- Authors: McGarry, Dylan K
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/371005 , vital:66402 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
- Description: Using artworks emergent from my career as a pracademic and scholar activist, I attempt to share a ‘tactile theory’ of being and doing, that refer mainly to response-abilities (i.e., abilities to respond in accountable ways) in scholar activist educational sociology. I aim to make visible (and tactile) the sometimes-invisible qualities and practices needed for navigating the eroded and dying ecological relations of our generation, as well as warming up and making pliable the heteronormative, capitalist, patriarchal and anthropocentric conventions that are associated with it. In order to warm and sculpt these normative conventions, I argue for the need for ‘suitably strange’ practice. I present six images and associated prose that aim to optimally disrupt these conventions, towards generative rethinking and embodying learning, scholar activism and justice, and from which I explore a tactile theory, an example and related response-ability for each. I end with a reflection of how these suitably strange artefacts can help us develop a new concept of proactive-cognitive justice or ‘justness’.
- Full Text:
Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid
- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
- Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
- Full Text:
Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
- Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
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Synergistic recognition and electrochemical sensing of 17β-Estradiol using ordered molecularly imprinted polymer-graphene oxide-silver nanoparticles composite films
- Regasa, Melkamu Biyana, Nyokong, Tebello
- Authors: Regasa, Melkamu Biyana , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295829 , vital:57382 , xlink:href="https://doi.org/10.1016/j.jelechem.2022.116713"
- Description: Synthetic molecularly imprinted polymers (MIPs) based functional materials become the best alternatives to alleviate the stability and cost issues related to biological receptors commonly used in biochemical sensors. To address this demand, we report the development of a highly selective and sensitive MIPs-based electrochemical sensor for the detection of 17β-estradiol (E2). The sensor was prepared based on the MIP-graphene oxide (GO)-silver nanoparticle (AgNP) nanocomposite functional materials electrodeposited on the surface of the glassy carbon electrode (GCE). At first, AgNp formation was facilitated by using ascorbic acid to reduce and stabilize it. A very stable MIP-GO-AgNP sensing layer with multifunctional units were formed using imidazole as a functional monomer (p-type-electron acceptor), GO (n-type-electron donor), and AgNP by using the electrodeposition method. The role of GO in the system is providing additional functional units to bind the template and improve materials morphology while that of AgNPs is acting as a catalyst and charge carrier. The characterization of the sensing materials was done by using Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, and cyclic voltammetry. After optimization of the essential parameters, the sensor was successfully applied to detect the target analyte using the square wave voltammetric technique. The prepared sensor exhibited a wide linear range of 10 fM-250 nM with the limit of detection and limit of quantification of 3.01 fM and 10.03 fM, respectively. The high percentage recoveries, sensitivity, repeatability, and easy fabrication of the MIP-GO-AgNP materials made the proposed sensor promising for environmental monitoring applications in the future.
- Full Text:
- Authors: Regasa, Melkamu Biyana , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295829 , vital:57382 , xlink:href="https://doi.org/10.1016/j.jelechem.2022.116713"
- Description: Synthetic molecularly imprinted polymers (MIPs) based functional materials become the best alternatives to alleviate the stability and cost issues related to biological receptors commonly used in biochemical sensors. To address this demand, we report the development of a highly selective and sensitive MIPs-based electrochemical sensor for the detection of 17β-estradiol (E2). The sensor was prepared based on the MIP-graphene oxide (GO)-silver nanoparticle (AgNP) nanocomposite functional materials electrodeposited on the surface of the glassy carbon electrode (GCE). At first, AgNp formation was facilitated by using ascorbic acid to reduce and stabilize it. A very stable MIP-GO-AgNP sensing layer with multifunctional units were formed using imidazole as a functional monomer (p-type-electron acceptor), GO (n-type-electron donor), and AgNP by using the electrodeposition method. The role of GO in the system is providing additional functional units to bind the template and improve materials morphology while that of AgNPs is acting as a catalyst and charge carrier. The characterization of the sensing materials was done by using Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy, and cyclic voltammetry. After optimization of the essential parameters, the sensor was successfully applied to detect the target analyte using the square wave voltammetric technique. The prepared sensor exhibited a wide linear range of 10 fM-250 nM with the limit of detection and limit of quantification of 3.01 fM and 10.03 fM, respectively. The high percentage recoveries, sensitivity, repeatability, and easy fabrication of the MIP-GO-AgNP materials made the proposed sensor promising for environmental monitoring applications in the future.
- Full Text:
Synthesis and conformational studies of 5-bromo-1-[(N-substituted-carbamoyl) methyl]-7-azabenzimidazoles
- Oluwafemi, Kola A, Klein, Rosalyn, Lobb, Kevin A, Tshiwawa, Tendamudzimu, Isaacs, Michelle, Hoppe, Heinrich C, Kaye, Perry T
- Authors: Oluwafemi, Kola A , Klein, Rosalyn , Lobb, Kevin A , Tshiwawa, Tendamudzimu , Isaacs, Michelle , Hoppe, Heinrich C , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452800 , vital:75171 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.133811"
- Description: The Cs2CO3-catalysed condensation of 5-bromo-7-azabenzimidazole with a series of bromomethyl ketones has afforded a small library of ten, novel 5-bromo-1-[(N-substututed-carbamoyl)methyl]-7-azabenzimidazoles. Rotamerism in the products, as evidenced by the splitting of 1H- and 13C-NMR signals, is attributed to hindered internal rotation about the amide N-C(=O) bond, and has been explored using dynamic NMR (DNMR) analysis and computational methods at the GIAO B3LYP/6-311+G(2d,p) level of theory. Coalescence temperatures have been obtained for representative examples and rotational barriers determined experimentally and theoretically. A detailed theoretical analysis has been undertaken to explore conformations which may contribute to the relative populations of the s-cis and s-trans rotamers. The products have also been screened for cytotoxicity and activity against two parasitic protozoan strains (Plasmodium falciparum and Trypanosoma brucei).
- Full Text:
- Authors: Oluwafemi, Kola A , Klein, Rosalyn , Lobb, Kevin A , Tshiwawa, Tendamudzimu , Isaacs, Michelle , Hoppe, Heinrich C , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452800 , vital:75171 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.133811"
- Description: The Cs2CO3-catalysed condensation of 5-bromo-7-azabenzimidazole with a series of bromomethyl ketones has afforded a small library of ten, novel 5-bromo-1-[(N-substututed-carbamoyl)methyl]-7-azabenzimidazoles. Rotamerism in the products, as evidenced by the splitting of 1H- and 13C-NMR signals, is attributed to hindered internal rotation about the amide N-C(=O) bond, and has been explored using dynamic NMR (DNMR) analysis and computational methods at the GIAO B3LYP/6-311+G(2d,p) level of theory. Coalescence temperatures have been obtained for representative examples and rotational barriers determined experimentally and theoretically. A detailed theoretical analysis has been undertaken to explore conformations which may contribute to the relative populations of the s-cis and s-trans rotamers. The products have also been screened for cytotoxicity and activity against two parasitic protozoan strains (Plasmodium falciparum and Trypanosoma brucei).
- Full Text:
Synthesis and conformational studies of 5-bromo-1-[(N-substituted-carbamoyl) methyl]-7-azabenzimidazoles
- Oluwafemi, Kola A, Klein, Rosalyn, Lobb, Kevin A, Tshiwawa, Tendamudzimu, Isaacs, Michelle, Hoppe, Heinrich C, Kaye, Perry T
- Authors: Oluwafemi, Kola A , Klein, Rosalyn , Lobb, Kevin A , Tshiwawa, Tendamudzimu , Isaacs, Michelle , Hoppe, Heinrich C , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/477672 , vital:78110 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.133811"
- Description: The Cs2CO3-catalysed condensation of 5-bromo-7-azabenzimidazole with a series of bromomethyl ketones has afforded a small library of ten, novel 5-bromo-1-[(N-substututed-carbamoyl)methyl]-7-azabenzimidazoles. Rotamerism in the products, as evidenced by the splitting of 1H- and 13C-NMR signals, is attributed to hindered internal rotation about the amide N-C(=O) bond, and has been explored using dynamic NMR (DNMR) analysis and computational methods at the GIAO B3LYP/6-311+G(2d,p) level of theory. Coalescence temperatures have been obtained for representative examples and rotational barriers determined experimentally and theoretically. A detailed theoretical analysis has been undertaken to explore conformations which may contribute to the relative populations of the s-cis and s-trans rotamers. The products have also been screened for cytotoxicity and activity against two parasitic protozoan strains (Plasmodium falciparum and Trypanosoma brucei).
- Full Text:
- Authors: Oluwafemi, Kola A , Klein, Rosalyn , Lobb, Kevin A , Tshiwawa, Tendamudzimu , Isaacs, Michelle , Hoppe, Heinrich C , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/477672 , vital:78110 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.133811"
- Description: The Cs2CO3-catalysed condensation of 5-bromo-7-azabenzimidazole with a series of bromomethyl ketones has afforded a small library of ten, novel 5-bromo-1-[(N-substututed-carbamoyl)methyl]-7-azabenzimidazoles. Rotamerism in the products, as evidenced by the splitting of 1H- and 13C-NMR signals, is attributed to hindered internal rotation about the amide N-C(=O) bond, and has been explored using dynamic NMR (DNMR) analysis and computational methods at the GIAO B3LYP/6-311+G(2d,p) level of theory. Coalescence temperatures have been obtained for representative examples and rotational barriers determined experimentally and theoretically. A detailed theoretical analysis has been undertaken to explore conformations which may contribute to the relative populations of the s-cis and s-trans rotamers. The products have also been screened for cytotoxicity and activity against two parasitic protozoan strains (Plasmodium falciparum and Trypanosoma brucei).
- Full Text:
Synthesis of 2, 3-dihydroxy-3-(N-substituted carbamoyl) propylphosphonic acid derivatives as hybrid DOXP-fosmidomycin analogues
- Mutorwa, Marius K, Lobb, Kevin A, Klein, Rosalyn, Blatch, Gregory L, Kaye, Perry T
- Authors: Mutorwa, Marius K , Lobb, Kevin A , Klein, Rosalyn , Blatch, Gregory L , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453212 , vital:75231 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132453"
- Description: A six-step synthetic pathway has been established to access a series of racemic 2,3-dihydroxy-3-(Nsubstituted carbamoyl)propylphosphonic acid derivatives, designed to contain structural features common to both the natural substrate 1-deoxy-D-xylulose 5-phosphate (DOXP) of the Plasmodium falciparum (Pf) DXR enzyme and its known inhibitor, fosmidomycin. Positive STD-NMR and in silico docking data obtained for some of the compounds indicate their capacity to bind to the analogous E.coli DXR enzyme.
- Full Text:
- Authors: Mutorwa, Marius K , Lobb, Kevin A , Klein, Rosalyn , Blatch, Gregory L , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453212 , vital:75231 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132453"
- Description: A six-step synthetic pathway has been established to access a series of racemic 2,3-dihydroxy-3-(Nsubstituted carbamoyl)propylphosphonic acid derivatives, designed to contain structural features common to both the natural substrate 1-deoxy-D-xylulose 5-phosphate (DOXP) of the Plasmodium falciparum (Pf) DXR enzyme and its known inhibitor, fosmidomycin. Positive STD-NMR and in silico docking data obtained for some of the compounds indicate their capacity to bind to the analogous E.coli DXR enzyme.
- Full Text:
Synthesis of 2, 3-dihydroxy-3-(N-substituted carbamoyl) propylphosphonic acid derivatives as hybrid DOXP-fosmidomycin analogues
- Mutorwa, Marius K, Lobb, Kevin A, Klein, Rosalyn, Blatch, Gregory L, Kaye, Perry T
- Authors: Mutorwa, Marius K , Lobb, Kevin A , Klein, Rosalyn , Blatch, Gregory L , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/477694 , vital:78112 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132453"
- Description: A six-step synthetic pathway has been established to access a series of racemic 2,3-dihydroxy-3-(N-substituted carbamoyl) propylphosphonic acid derivatives, designed to contain structural features common to both the natural substrate 1-deoxy-D-xylulose 5-phosphate (DOXP) of the Plasmodium falciparum (Pf) DXR enzyme and its known inhibitor, fosmidomycin. Positive STD-NMR and in silico docking data obtained for some of the compounds indicate their capacity to bind to the analogous E.coli DXR enzyme.
- Full Text:
- Authors: Mutorwa, Marius K , Lobb, Kevin A , Klein, Rosalyn , Blatch, Gregory L , Kaye, Perry T
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/477694 , vital:78112 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.132453"
- Description: A six-step synthetic pathway has been established to access a series of racemic 2,3-dihydroxy-3-(N-substituted carbamoyl) propylphosphonic acid derivatives, designed to contain structural features common to both the natural substrate 1-deoxy-D-xylulose 5-phosphate (DOXP) of the Plasmodium falciparum (Pf) DXR enzyme and its known inhibitor, fosmidomycin. Positive STD-NMR and in silico docking data obtained for some of the compounds indicate their capacity to bind to the analogous E.coli DXR enzyme.
- Full Text: