Prioritising biological control agents for release against Sporobolus pyramidalis and Sporobolus natalensis (Poaceae) in Australia
- Authors: Sutton, Guy Frederick
- Date: 2021
- Subjects: Grasses -- Diseases and pests , Bruchophagus , Wasps , Alien plants -- Biological control -- Australia , Sporobolus -- Biological control -- Africa , Sporobolus -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insects as biological pest control agents -- Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172445 , vital:42201 , 10.21504/10962/172445
- Description: Sporobolus pyramidalis Beauv. and S. natalensis (Steud.) Th. Dur. and Schinz. (giant rat’s tail grass) (Poaceae), invade rangelands and pastures in eastern Australia, costing the livestock industry approximately AUS$ 60 million per annum in grazing losses. Mechanical and chemical control options are costly and largely ineffective. Biological control is viewed as the most promising control option, however this management strategy has largely been avoided for grasses, due to their perceived lack of suitably host-specific and damaging natural enemies. In this thesis, the prospects for using biological control against S. pyramidalis and S. natalensis in Australia was assessed, in light of these potential challenges. Climate matching models were used to identify high-priority geographic regions within the plants’ native distributions to survey for potential biological control agents. High-priority regions to perform surveys were identified by modelling the climatic suitability for S. pyramidalis and S. natalensis in sub-Saharan Africa (i.e. their potential native ranges’), and climatic compatibility with regions where biological control is intended in Australia. High-priority regions for S. pyramidalis included: (1) coastal East Africa, ranging from north-eastern South Africa to Uganda, including south-eastern DRC, (2) some parts of West Africa, including inland regions of the Ivory Coast and western Nigeria, (3) northern Angola and (4) eastern Madagascar, and for S. natalensis included: (1) eastern South Africa, (2) eastern Zimbabwe, (3) Burundi, (4) central Ethiopia and (5) central Madagascar. Prospective control agents collected from these regions have the highest probability of establishing and proliferating in Australia, if released. In surveys of the insect assemblages on S. pyramidalis and S. natalensis in the climatically-matched region of eastern South Africa fifteen insect herbivores associated with the grasses were identified. Insect feeding guild, geographic distributions, and seasonal abundances suggest that three stem-boring phytophagous wasps, Tetramesa sp. 1, Tetramesa sp. 2 and Bruchophagus sp. 1 (Hymenoptera: Eurytomidae), have potential as control agents. Species accumulation curves indicated that additional surveys in South Africa are unlikely to yield additional potential control agents. Field host-range surveys of 47 non-target grass species in South Africa showed that Tetramesa sp. 1, Tetramesa sp. 2, and Bruchophagus sp. 1, were only recorded from S. pyramidalis and S. natalensis. Integrating field host-range with phylogenetic relationships between plant species indicated that no native Australian Sporobolus species or economic crops and pastures are expected to be attacked by these wasps. All three wasp species are predicted to be suitably host-specific for release in Australia. Three other endophagous herbivores attacked non-target native African Sporobolus species that share a close phylogenetic relationship to native Australian Sporobolus species, and therefore, demonstrate considerable risk of non-target damage. These species should not be considered as potential control agents. Under native-range, open-field conditions, Tetramesa sp. 1 caused an approximately 5-fold greater reduction in plant survival and reproductive output than Tetramesa sp. 2 and Bruchophagus sp. 1. Tetramesa sp. 1 in combination with Tetramesa sp. 2 did not significantly increase the level of damage, while Bruchophagus sp. 1 may decrease the efficiency of Tetramesa sp. 1, if released in combination. Tetramesa 1 is therefore the most promising candidate agent. Prioritising potential agents using predicted efficacy allowed otherwise equally suitable prospective agents to be prioritised in a strategic manner. Prioritising which natural enemies to target as biological control agents is a complex task. Field host range and damage assessments in the native range may provide more realistic data than typical studies performed under artificial conditions in a laboratory or quarantine. Moreover, it could assist practitioners in prioritising the most suitable agent(s) at the earliest stage in the programme as possible. This study demonstrated that grasses are suitable targets for biological control as they can harbour host-specific and damaging natural enemies.
- Full Text:
- Date Issued: 2021
- Authors: Sutton, Guy Frederick
- Date: 2021
- Subjects: Grasses -- Diseases and pests , Bruchophagus , Wasps , Alien plants -- Biological control -- Australia , Sporobolus -- Biological control -- Africa , Sporobolus -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insects as biological pest control agents -- Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172445 , vital:42201 , 10.21504/10962/172445
- Description: Sporobolus pyramidalis Beauv. and S. natalensis (Steud.) Th. Dur. and Schinz. (giant rat’s tail grass) (Poaceae), invade rangelands and pastures in eastern Australia, costing the livestock industry approximately AUS$ 60 million per annum in grazing losses. Mechanical and chemical control options are costly and largely ineffective. Biological control is viewed as the most promising control option, however this management strategy has largely been avoided for grasses, due to their perceived lack of suitably host-specific and damaging natural enemies. In this thesis, the prospects for using biological control against S. pyramidalis and S. natalensis in Australia was assessed, in light of these potential challenges. Climate matching models were used to identify high-priority geographic regions within the plants’ native distributions to survey for potential biological control agents. High-priority regions to perform surveys were identified by modelling the climatic suitability for S. pyramidalis and S. natalensis in sub-Saharan Africa (i.e. their potential native ranges’), and climatic compatibility with regions where biological control is intended in Australia. High-priority regions for S. pyramidalis included: (1) coastal East Africa, ranging from north-eastern South Africa to Uganda, including south-eastern DRC, (2) some parts of West Africa, including inland regions of the Ivory Coast and western Nigeria, (3) northern Angola and (4) eastern Madagascar, and for S. natalensis included: (1) eastern South Africa, (2) eastern Zimbabwe, (3) Burundi, (4) central Ethiopia and (5) central Madagascar. Prospective control agents collected from these regions have the highest probability of establishing and proliferating in Australia, if released. In surveys of the insect assemblages on S. pyramidalis and S. natalensis in the climatically-matched region of eastern South Africa fifteen insect herbivores associated with the grasses were identified. Insect feeding guild, geographic distributions, and seasonal abundances suggest that three stem-boring phytophagous wasps, Tetramesa sp. 1, Tetramesa sp. 2 and Bruchophagus sp. 1 (Hymenoptera: Eurytomidae), have potential as control agents. Species accumulation curves indicated that additional surveys in South Africa are unlikely to yield additional potential control agents. Field host-range surveys of 47 non-target grass species in South Africa showed that Tetramesa sp. 1, Tetramesa sp. 2, and Bruchophagus sp. 1, were only recorded from S. pyramidalis and S. natalensis. Integrating field host-range with phylogenetic relationships between plant species indicated that no native Australian Sporobolus species or economic crops and pastures are expected to be attacked by these wasps. All three wasp species are predicted to be suitably host-specific for release in Australia. Three other endophagous herbivores attacked non-target native African Sporobolus species that share a close phylogenetic relationship to native Australian Sporobolus species, and therefore, demonstrate considerable risk of non-target damage. These species should not be considered as potential control agents. Under native-range, open-field conditions, Tetramesa sp. 1 caused an approximately 5-fold greater reduction in plant survival and reproductive output than Tetramesa sp. 2 and Bruchophagus sp. 1. Tetramesa sp. 1 in combination with Tetramesa sp. 2 did not significantly increase the level of damage, while Bruchophagus sp. 1 may decrease the efficiency of Tetramesa sp. 1, if released in combination. Tetramesa 1 is therefore the most promising candidate agent. Prioritising potential agents using predicted efficacy allowed otherwise equally suitable prospective agents to be prioritised in a strategic manner. Prioritising which natural enemies to target as biological control agents is a complex task. Field host range and damage assessments in the native range may provide more realistic data than typical studies performed under artificial conditions in a laboratory or quarantine. Moreover, it could assist practitioners in prioritising the most suitable agent(s) at the earliest stage in the programme as possible. This study demonstrated that grasses are suitable targets for biological control as they can harbour host-specific and damaging natural enemies.
- Full Text:
- Date Issued: 2021
Probing the binding sites of novel 2-substituted imidazole-4,5-dicarboxylic acids : Towards new imidazole-based drugs
- Authors: Clark, Candyce Raine
- Date: 2021
- Subjects: Heterocyclic compounds Coordination compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50848 , vital:42957
- Description: A series of benzimidazole and imidazole-4,5-dicarboxylic acids were prepared using known and adapted protocols. Novel ligands synthesised in this study include 2-tert-butyl-benzimidazole, 2-tert-butyl-imidazole-4,5-dicarboxylic acid, an intermediate in the synthesis of 1,2- bis(2-benzimidazyl)-1,2,-dihydroxyethane and 2-(2-hydroxyphenyl)-benzimidazole with a salicylic acid co-crystallisate. All ligands prepared were reacted with metal salt solutions in order to prepare metal coordination compounds. Complexes with Cu(II), Ag(I), Mn(II), Ni(II) and Cd(II) ions and 2-phenyl-imidazole-4,5-dicarboxylic acid were prepared, as well as Cu(II) and Mn(II) with 2-trifluoro-methyl-imidazole-4,5-dicarboxylic acid and Cu(II) ions with 2-(2- hydroxyphenyl)-benzimidazole. The ligands and complexes were characterised by means of single-crystal X-ray diffraction studies, NMR analysis, UV spectrophotometric analysis and IR spectroscopy. DFT studies were carried out for selected ligands in order to provide theoretical values for comparison. Antimicrobial studies were performed on some of the ligands and complexes and these results show promise for the future development of new imidazole-based drugs.
- Full Text:
- Date Issued: 2021
- Authors: Clark, Candyce Raine
- Date: 2021
- Subjects: Heterocyclic compounds Coordination compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50848 , vital:42957
- Description: A series of benzimidazole and imidazole-4,5-dicarboxylic acids were prepared using known and adapted protocols. Novel ligands synthesised in this study include 2-tert-butyl-benzimidazole, 2-tert-butyl-imidazole-4,5-dicarboxylic acid, an intermediate in the synthesis of 1,2- bis(2-benzimidazyl)-1,2,-dihydroxyethane and 2-(2-hydroxyphenyl)-benzimidazole with a salicylic acid co-crystallisate. All ligands prepared were reacted with metal salt solutions in order to prepare metal coordination compounds. Complexes with Cu(II), Ag(I), Mn(II), Ni(II) and Cd(II) ions and 2-phenyl-imidazole-4,5-dicarboxylic acid were prepared, as well as Cu(II) and Mn(II) with 2-trifluoro-methyl-imidazole-4,5-dicarboxylic acid and Cu(II) ions with 2-(2- hydroxyphenyl)-benzimidazole. The ligands and complexes were characterised by means of single-crystal X-ray diffraction studies, NMR analysis, UV spectrophotometric analysis and IR spectroscopy. DFT studies were carried out for selected ligands in order to provide theoretical values for comparison. Antimicrobial studies were performed on some of the ligands and complexes and these results show promise for the future development of new imidazole-based drugs.
- Full Text:
- Date Issued: 2021
Progress and prospects for the biological control of invasive alien grasses Poaceae) in South Africa
- Sutton, Guy F, Bownes, Angela, Visser, Vernon, Mapaura, Anthony, Canavan, Kim N
- Authors: Sutton, Guy F , Bownes, Angela , Visser, Vernon , Mapaura, Anthony , Canavan, Kim N
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414448 , vital:71147 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a12"
- Description: Historically, invasive alien grasses have not been considered a major threat in South Africa, and as a result, very few resources are allocated to their management. However, there is an increasing awareness of the severe environmental and socio-economic impacts of invasive grasses and the need for appropriate management options for their control. South Africa has a long history of successfully implementing weed biological control (biocontrol) to manage invasive alien plants, however much like the rest of the world, invasive grasses do not feature prominently as targets for biocontrol. The implementation and early indicators of success of the few grass biocontrol programmes globally and the finding that grasses can be suitable targets, suggests that biocontrol could start to play an important role in managing invasive alien grasses in South Africa. In this paper, we evaluated the prospects for implementing novel grass biocontrol projects over the next ten years against 48 grasses that have been determined to represent the highest risk based on their current environmental and economic impacts. The grasses were ranked in order of priority using the Biological Control Target Selection system. Five grasses were prioritised – Arundo donax L., Cortaderia jubata (Lem.) Stapf, Cortaderia selloana (Schult and Schult) Asch. and Graebn., Nassella trichotoma (Hack. ex Arech.), and Glyceria maxima (Hartm.) Holmb., based on attributes that make them suitable biocontrol targets. Arundo donax has already been the target of a biocontrol programme in South Africa. We reviewed the progress made towards the biocontrol of this species and discuss how this programme could be developed going forward. Moreover, we outline how biocontrol could be implemented to manage the remaining four high-priority targets. While biocontrol of grasses is not without its challenges (e.g. unresolved taxonomies, conflicts of interest and a lack of supporting legislation), South Africa has an opportunity to learn from existing global research and begin to invest in biocontrol of high-priority species that are in most need of control.
- Full Text:
- Date Issued: 2021
Progress and prospects for the biological control of invasive alien grasses Poaceae) in South Africa
- Authors: Sutton, Guy F , Bownes, Angela , Visser, Vernon , Mapaura, Anthony , Canavan, Kim N
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414448 , vital:71147 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a12"
- Description: Historically, invasive alien grasses have not been considered a major threat in South Africa, and as a result, very few resources are allocated to their management. However, there is an increasing awareness of the severe environmental and socio-economic impacts of invasive grasses and the need for appropriate management options for their control. South Africa has a long history of successfully implementing weed biological control (biocontrol) to manage invasive alien plants, however much like the rest of the world, invasive grasses do not feature prominently as targets for biocontrol. The implementation and early indicators of success of the few grass biocontrol programmes globally and the finding that grasses can be suitable targets, suggests that biocontrol could start to play an important role in managing invasive alien grasses in South Africa. In this paper, we evaluated the prospects for implementing novel grass biocontrol projects over the next ten years against 48 grasses that have been determined to represent the highest risk based on their current environmental and economic impacts. The grasses were ranked in order of priority using the Biological Control Target Selection system. Five grasses were prioritised – Arundo donax L., Cortaderia jubata (Lem.) Stapf, Cortaderia selloana (Schult and Schult) Asch. and Graebn., Nassella trichotoma (Hack. ex Arech.), and Glyceria maxima (Hartm.) Holmb., based on attributes that make them suitable biocontrol targets. Arundo donax has already been the target of a biocontrol programme in South Africa. We reviewed the progress made towards the biocontrol of this species and discuss how this programme could be developed going forward. Moreover, we outline how biocontrol could be implemented to manage the remaining four high-priority targets. While biocontrol of grasses is not without its challenges (e.g. unresolved taxonomies, conflicts of interest and a lack of supporting legislation), South Africa has an opportunity to learn from existing global research and begin to invest in biocontrol of high-priority species that are in most need of control.
- Full Text:
- Date Issued: 2021
Promising photodynamic antimicrobial activity of polyimine substituted zinc phthalocyanine and its polycationic derivative when conjugated to nitrogen, sulfur, co-doped graphene quantum dots against Staphylococcus aureus
- Sen, Pinar, Nyokong, Tebello
- Authors: Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185304 , vital:44363 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102300"
- Description: Antimicrobial resistance is a most important problem facing the treatment of infectious diseases. Antimicrobial photodynamic therapy is an alternative treatment strategy, considered to be cost-effective and feasible. For this purpose, octa-imine substituted ZnPc (3) have been prepared and conjugated to nitrogen, sulfur co-doped graphene quantum dots (N,S-GQDs) through π-π stacking. The photophysical and photochemical properties of Pc alone and and Pc-conjugated to the GQD nanomaterial such as absorption, fluorescence, fluorescence life time, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions before in vitro cell studies. The PACT activity of prepared structures was investigated against Gram-positive (Staphylococcus aureus). Our results suggest that the in the case of conjugation of zinc Pc to N,S-GQDs, photodynamic inactivation increased with the 100 % reduction percentage.
- Full Text:
- Date Issued: 2021
- Authors: Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185304 , vital:44363 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102300"
- Description: Antimicrobial resistance is a most important problem facing the treatment of infectious diseases. Antimicrobial photodynamic therapy is an alternative treatment strategy, considered to be cost-effective and feasible. For this purpose, octa-imine substituted ZnPc (3) have been prepared and conjugated to nitrogen, sulfur co-doped graphene quantum dots (N,S-GQDs) through π-π stacking. The photophysical and photochemical properties of Pc alone and and Pc-conjugated to the GQD nanomaterial such as absorption, fluorescence, fluorescence life time, singlet oxygen quantum yields, triplet state quantum yields and exited state lifetimes were investigated in solutions before in vitro cell studies. The PACT activity of prepared structures was investigated against Gram-positive (Staphylococcus aureus). Our results suggest that the in the case of conjugation of zinc Pc to N,S-GQDs, photodynamic inactivation increased with the 100 % reduction percentage.
- Full Text:
- Date Issued: 2021
Prospects for the biological control of Northern Temperate Weeds in South Africa
- Authors: Martin, Grant D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414478 , vital:71151 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a10"
- Description: The Northern Temperate Weeds programme is a novel biological control (biocontrol) programme started in 2017, with the aim of reducing the impacts of northern temperate weeds that are common, widespread and problematic in the high elevation grasslands of South Africa. As these regions are the most important systems for water security, providing nearly 50% of all water run-off, it is surprising that these species were not targeted for biocontrol previously. Thus far, research has focused on biocontrol feasibility as well as ecological and socio-economic impact studies on several northern temperate weeds, including Pyracantha angustifolia (Franch.) C.K.Schneid, Rosa rubiginosa L., Cotoneaster spp., Rubus spp., (all Rosaceae) and Salix spp. (Salicaceae). In addition, research conducted in the USA and Europe on the natural enemies associated with two of these species, Robinia pseudoacacia L. and Gleditsia triacanthos L. (both Fabaceae and native to the USA), have provided South African researchers with the necessary foundation to initiate programmes against these weeds. Research in South Africa is currently focused on pre-release studies on R. pseudoacacia, using the leaf miner Odontota dorsalis Thunberg (Coleoptera: Chrysomelidae) and the black locust midge Obolodiplosis robiniae Haldeman (Diptera: Cecidomyiidae), and on G. triacanthos, using a seed bruchid, Amblycerus robiniae F. (Coleoptera: Chrysomelidae). Progress with these programmes and potential constraints that may limit success, are discussed.
- Full Text:
- Date Issued: 2021
- Authors: Martin, Grant D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414478 , vital:71151 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a10"
- Description: The Northern Temperate Weeds programme is a novel biological control (biocontrol) programme started in 2017, with the aim of reducing the impacts of northern temperate weeds that are common, widespread and problematic in the high elevation grasslands of South Africa. As these regions are the most important systems for water security, providing nearly 50% of all water run-off, it is surprising that these species were not targeted for biocontrol previously. Thus far, research has focused on biocontrol feasibility as well as ecological and socio-economic impact studies on several northern temperate weeds, including Pyracantha angustifolia (Franch.) C.K.Schneid, Rosa rubiginosa L., Cotoneaster spp., Rubus spp., (all Rosaceae) and Salix spp. (Salicaceae). In addition, research conducted in the USA and Europe on the natural enemies associated with two of these species, Robinia pseudoacacia L. and Gleditsia triacanthos L. (both Fabaceae and native to the USA), have provided South African researchers with the necessary foundation to initiate programmes against these weeds. Research in South Africa is currently focused on pre-release studies on R. pseudoacacia, using the leaf miner Odontota dorsalis Thunberg (Coleoptera: Chrysomelidae) and the black locust midge Obolodiplosis robiniae Haldeman (Diptera: Cecidomyiidae), and on G. triacanthos, using a seed bruchid, Amblycerus robiniae F. (Coleoptera: Chrysomelidae). Progress with these programmes and potential constraints that may limit success, are discussed.
- Full Text:
- Date Issued: 2021
Push-pull type Co (III) corroles
- Niu, Yingjie, Zhu, Weihua, Mack, John, Dubazana, Nadine, Nyokong, Tebello, Fu, Bo, Xu, Haijun, Liang, Xu
- Authors: Niu, Yingjie , Zhu, Weihua , Mack, John , Dubazana, Nadine , Nyokong, Tebello , Fu, Bo , Xu, Haijun , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190826 , vital:45032 , xlink:href="https://doi.org/10.1142/S1088424621500279"
- Description: The rational design and preparation of three A2B type Co(III)triarylcorroles with push- and pull-substituents are reported. The structure-property relationships were identified by comparing their optically spectroscopic and electrochemical properties to trends predicted in DFT and TD-DFT calculations. The results demonstrate that the Co(III)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolutions (HERs) and oxygen reductions (ORRs), and that their reactivity can be modulated by changing the meso-B-substituent of the Co(III)Corroles.
- Full Text:
- Date Issued: 2021
- Authors: Niu, Yingjie , Zhu, Weihua , Mack, John , Dubazana, Nadine , Nyokong, Tebello , Fu, Bo , Xu, Haijun , Liang, Xu
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190826 , vital:45032 , xlink:href="https://doi.org/10.1142/S1088424621500279"
- Description: The rational design and preparation of three A2B type Co(III)triarylcorroles with push- and pull-substituents are reported. The structure-property relationships were identified by comparing their optically spectroscopic and electrochemical properties to trends predicted in DFT and TD-DFT calculations. The results demonstrate that the Co(III)triarylcorroles are highly efficient catalysts for electrocatalyzed hydrogen evolutions (HERs) and oxygen reductions (ORRs), and that their reactivity can be modulated by changing the meso-B-substituent of the Co(III)Corroles.
- Full Text:
- Date Issued: 2021
Quantifying the shift in network usage upon bandwidth upgrade
- Okuthe, J A, Terzoli, Alfredo
- Authors: Okuthe, J A , Terzoli, Alfredo
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431003 , vital:72735 , https://doi.org/10.1007/978-3-031-06374-9_22
- Description: Traffic flow classification is an important enabler in network design, ca-pacity planning, identification of user requirements and possible track-ing of user population growth based on network usage. In this paper, results from the Internet traffic flow characterization in 1 Mbps commu-nity network for a three-week snapshot representing three months of study show that during peak traffic, the network is overwhelmed and service degradation occurs. When the network is upgraded to 10 Mbps the network bandwidth utilization immediately increases dramatically to close in on the new capacity with 20% left unused during peak traffic. The situation gets worse one month later where the network utilization is only 3% away from the maximum capacity. Traffic categorization show that the applications crossing the network are legitimate and accepta-ble. Since 10 Mbps bandwidth is the capacity that is sustainable for the community and supported by existing technology, bandwidth manage-ment is essential to ensure the network remains usable and continues to provide acceptable user experience.
- Full Text:
- Date Issued: 2021
- Authors: Okuthe, J A , Terzoli, Alfredo
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431003 , vital:72735 , https://doi.org/10.1007/978-3-031-06374-9_22
- Description: Traffic flow classification is an important enabler in network design, ca-pacity planning, identification of user requirements and possible track-ing of user population growth based on network usage. In this paper, results from the Internet traffic flow characterization in 1 Mbps commu-nity network for a three-week snapshot representing three months of study show that during peak traffic, the network is overwhelmed and service degradation occurs. When the network is upgraded to 10 Mbps the network bandwidth utilization immediately increases dramatically to close in on the new capacity with 20% left unused during peak traffic. The situation gets worse one month later where the network utilization is only 3% away from the maximum capacity. Traffic categorization show that the applications crossing the network are legitimate and accepta-ble. Since 10 Mbps bandwidth is the capacity that is sustainable for the community and supported by existing technology, bandwidth manage-ment is essential to ensure the network remains usable and continues to provide acceptable user experience.
- Full Text:
- Date Issued: 2021
Rapid Synthesis of Thiol-Co-Capped-CdTe/CdSe/ZnSe Core Shell-Shell Nanoparticles
- Daramola, Olamide, Siwe-Noundou, Xavier, Tseki, Potlaki, Krause, Rui W M
- Authors: Daramola, Olamide , Siwe-Noundou, Xavier , Tseki, Potlaki , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191758 , vital:45161 , xlink:href="https://doi.org/10.3390/nano11051193"
- Description: CdTe QDs has been demonstrated in many studies to possess good outstanding optical and photo-physical properties. However, it has been established from literature that the toxic Cd2+ that tends to leak out into nearby solutions can be protected by less toxic ZnS or ZnSe shells leading to the synthesis of core-shells and multi-core-shells. Hence, this has allowed the synthesis of CdTe multi-core-shells to have gained much interest. The preparation of most CdTe multi-core-shells reported from various studies usually has a longer reaction time (6–24 h) in reaching their highest emission maxima. The synthesis of CdTe multi-core-shells in this study only took 35 min to obtain a highest emission maximum compared to what has been reported from the literature. CdTe multi-core-shells were synthesized by injecting 7, 14, and 21 mL each of Zn complex solution and Se ions into the reacting mixture containing CdTe core-shells (3 h) at 5 min intervals over a 35 min reaction time. The emission maxima of the MPA-TGA-CdTe multi-core-shells at 21 mL injection was recorded around 625 nm. Therefore, we are reporting the rapid synthesis of five different thiol co-capped CdTe/CdSe/ZnSe multi-core-shell QDs with the highest emission maxima obtained at 35 min reaction time.
- Full Text:
- Date Issued: 2021
- Authors: Daramola, Olamide , Siwe-Noundou, Xavier , Tseki, Potlaki , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191758 , vital:45161 , xlink:href="https://doi.org/10.3390/nano11051193"
- Description: CdTe QDs has been demonstrated in many studies to possess good outstanding optical and photo-physical properties. However, it has been established from literature that the toxic Cd2+ that tends to leak out into nearby solutions can be protected by less toxic ZnS or ZnSe shells leading to the synthesis of core-shells and multi-core-shells. Hence, this has allowed the synthesis of CdTe multi-core-shells to have gained much interest. The preparation of most CdTe multi-core-shells reported from various studies usually has a longer reaction time (6–24 h) in reaching their highest emission maxima. The synthesis of CdTe multi-core-shells in this study only took 35 min to obtain a highest emission maximum compared to what has been reported from the literature. CdTe multi-core-shells were synthesized by injecting 7, 14, and 21 mL each of Zn complex solution and Se ions into the reacting mixture containing CdTe core-shells (3 h) at 5 min intervals over a 35 min reaction time. The emission maxima of the MPA-TGA-CdTe multi-core-shells at 21 mL injection was recorded around 625 nm. Therefore, we are reporting the rapid synthesis of five different thiol co-capped CdTe/CdSe/ZnSe multi-core-shell QDs with the highest emission maxima obtained at 35 min reaction time.
- Full Text:
- Date Issued: 2021
Re-engineering imperatives to enhance the effectiveness of municipal public accounts committees in South African municipalities
- Mofolo, Malefetsane A., Adonis, Vuyo
- Authors: Mofolo, Malefetsane A. , Adonis, Vuyo
- Date: 2021
- Subjects: Criminal liability Maleficence Municipal finance--Accounting Reengineering (Management) Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7179 , vital:53082 , xlink:href="https://doi.org/10.4102/apsdpr.v9i1.510"
- Description: Background: After 26 years into democracy and 20 years of the new local government operations, the state of the majority of municipalities in South Africa still leaves much to be desired, as they are plagued with maleficence. What is concerning is that these negative tendencies that are troubling local government occur even under the watchful eye of the municipal public accounts committees (MPACs). Aim: The aim of this study was to evaluate the composition and the role of MPACs, which have experienced a number of challenges since they were introduced in response to the widely held perception of the culture of lack of accountability in South African municipalities. Methods: This article is theoretical in nature, and it draws its arguments from secondary data in order to understand the composition and the role of MPACs, including its challenges. Results: This study regards the composition of the MPAC as lacking the necessary vigour to be efficient and effective in executing its duties, particularly when considering the challenges and political influences that it tends to face in its operations. Conclusion: The study concludes that there is a need for re-engineering of the composition and the role of the MPAC in order to ensure that it executes its functions efficiently and effectively. Consequently, the study recommends three cardinal pillars that must be given attention in re-engineering the MPAC: policy, authority and power. Keywords: Internal accountability; maleficence; municipalities; municipal public accounts committees; re-engineering
- Full Text:
- Date Issued: 2021
- Authors: Mofolo, Malefetsane A. , Adonis, Vuyo
- Date: 2021
- Subjects: Criminal liability Maleficence Municipal finance--Accounting Reengineering (Management) Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7179 , vital:53082 , xlink:href="https://doi.org/10.4102/apsdpr.v9i1.510"
- Description: Background: After 26 years into democracy and 20 years of the new local government operations, the state of the majority of municipalities in South Africa still leaves much to be desired, as they are plagued with maleficence. What is concerning is that these negative tendencies that are troubling local government occur even under the watchful eye of the municipal public accounts committees (MPACs). Aim: The aim of this study was to evaluate the composition and the role of MPACs, which have experienced a number of challenges since they were introduced in response to the widely held perception of the culture of lack of accountability in South African municipalities. Methods: This article is theoretical in nature, and it draws its arguments from secondary data in order to understand the composition and the role of MPACs, including its challenges. Results: This study regards the composition of the MPAC as lacking the necessary vigour to be efficient and effective in executing its duties, particularly when considering the challenges and political influences that it tends to face in its operations. Conclusion: The study concludes that there is a need for re-engineering of the composition and the role of the MPAC in order to ensure that it executes its functions efficiently and effectively. Consequently, the study recommends three cardinal pillars that must be given attention in re-engineering the MPAC: policy, authority and power. Keywords: Internal accountability; maleficence; municipalities; municipal public accounts committees; re-engineering
- Full Text:
- Date Issued: 2021
Re-thinking freedom: selected Life-Writings of South African Born-frees
- Authors: Mpendulo, Mashumi
- Date: 2021
- Subjects: Born-Frees , Freedom of expression , Post-apartheid era -- South Africa
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3400 , vital:43339
- Description: Ideas of freedom in post-apartheid South Africa cannot be understood in isolation from the lived experiences of the people we often consider as the future of South Africa. Freedom is a time-bound value whose meaning keeps changing as time goes by, and our understanding of freedom before 1994 cannot be the same as today. With close reference to the selected life writings of South African born-frees, this study examines ideas of freedom as expressed in these texts written from the perspectives of ordinary young black people in post-apartheid South Africa. It unpacks the youth’s rejection of the tag ‘born-free’ by bringing out the difficulties of their upbringing in poverty and inequality. This work argues that poverty, inequality, unemployment, and dilapidated infrastructure in public schools are still very much a feature of post-apartheid South Africa, and that the government is yet to fully transform the lives of ordinary black people who much as they try to do so themselves, are still faced with structural inequalities, physical and symbolic violence. Through decolonial theory, the selected texts are analysed to trace the legacies of colonialism and apartheid and how notions of freedom have changed over time. , Thesis (MA) -- Faculty of Humanities, Social Sciences and Law, 2021
- Full Text:
- Date Issued: 2021
- Authors: Mpendulo, Mashumi
- Date: 2021
- Subjects: Born-Frees , Freedom of expression , Post-apartheid era -- South Africa
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3400 , vital:43339
- Description: Ideas of freedom in post-apartheid South Africa cannot be understood in isolation from the lived experiences of the people we often consider as the future of South Africa. Freedom is a time-bound value whose meaning keeps changing as time goes by, and our understanding of freedom before 1994 cannot be the same as today. With close reference to the selected life writings of South African born-frees, this study examines ideas of freedom as expressed in these texts written from the perspectives of ordinary young black people in post-apartheid South Africa. It unpacks the youth’s rejection of the tag ‘born-free’ by bringing out the difficulties of their upbringing in poverty and inequality. This work argues that poverty, inequality, unemployment, and dilapidated infrastructure in public schools are still very much a feature of post-apartheid South Africa, and that the government is yet to fully transform the lives of ordinary black people who much as they try to do so themselves, are still faced with structural inequalities, physical and symbolic violence. Through decolonial theory, the selected texts are analysed to trace the legacies of colonialism and apartheid and how notions of freedom have changed over time. , Thesis (MA) -- Faculty of Humanities, Social Sciences and Law, 2021
- Full Text:
- Date Issued: 2021
Review of the Traditional Uses, Phytochemistry, and Pharmacological Activities of Rhoicissus Species (Vitaceae)
- Dube, Nondumiso, Siwe-Noundou, Xavier, Krause, Rui W M, Kemboi, Douglas, Tembu, Vuyelwa J, Manicum, Amanda-Lee
- Authors: Dube, Nondumiso , Siwe-Noundou, Xavier , Krause, Rui W M , Kemboi, Douglas , Tembu, Vuyelwa J , Manicum, Amanda-Lee
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191769 , vital:45162 , xlink:href="https://doi.org/10.3390/molecules26082306"
- Description: Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.
- Full Text:
- Date Issued: 2021
- Authors: Dube, Nondumiso , Siwe-Noundou, Xavier , Krause, Rui W M , Kemboi, Douglas , Tembu, Vuyelwa J , Manicum, Amanda-Lee
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191769 , vital:45162 , xlink:href="https://doi.org/10.3390/molecules26082306"
- Description: Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.
- Full Text:
- Date Issued: 2021
Rural Tourism and Inclusive Development in Port St. Johns - South Africa
- Acha-Anyi, Paul Nkemngu, Ndolose, Ludwe, Solomon, Khunou Pula
- Authors: Acha-Anyi, Paul Nkemngu , Ndolose, Ludwe , Solomon, Khunou Pula
- Date: 2021
- Subjects: Rural tourism Community Inclusive development; Sustainable development Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7023 , vital:52758 , xlink:href=":https://doi.org/10.46222/ajhtl.19770720.197"
- Description: The purpose of this study was to explore ways of achieving an inclusive approach to tourism development in rural communities. Although tourism has generally been recommended as a means of orchestrating development in rural communities, achieving this laudable goal has often been illusive due to the fragmented approach adopted by tourism stakeholders. An exploratory quantitative research approach was adopted by using a structured survey instrument to generate 307 valid responses from community members in Port St. John in the Eastern Cape Province (ECP) of South Africa. Results obtained reveal similarities and some differences based on demographic characteristics with regards to the benefits of rural tourism to the community. Importantly, the study illuminates the fragmented way in which residents perceive tourism benefits, both from a gender perspective and personal benefit versus community dichotomy. The paper discusses policy as well as practical local economic development implications. Keywords: Rural tourism; community; Port St. Johns; inclusive development; sustainable development
- Full Text:
- Date Issued: 2021
- Authors: Acha-Anyi, Paul Nkemngu , Ndolose, Ludwe , Solomon, Khunou Pula
- Date: 2021
- Subjects: Rural tourism Community Inclusive development; Sustainable development Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7023 , vital:52758 , xlink:href=":https://doi.org/10.46222/ajhtl.19770720.197"
- Description: The purpose of this study was to explore ways of achieving an inclusive approach to tourism development in rural communities. Although tourism has generally been recommended as a means of orchestrating development in rural communities, achieving this laudable goal has often been illusive due to the fragmented approach adopted by tourism stakeholders. An exploratory quantitative research approach was adopted by using a structured survey instrument to generate 307 valid responses from community members in Port St. John in the Eastern Cape Province (ECP) of South Africa. Results obtained reveal similarities and some differences based on demographic characteristics with regards to the benefits of rural tourism to the community. Importantly, the study illuminates the fragmented way in which residents perceive tourism benefits, both from a gender perspective and personal benefit versus community dichotomy. The paper discusses policy as well as practical local economic development implications. Keywords: Rural tourism; community; Port St. Johns; inclusive development; sustainable development
- Full Text:
- Date Issued: 2021
Sex, gender and Uvalo/Letswalo centred spirituality
- Magadla, Siphokazi, Magoqwana, Babalwa, Motsemme, Nthabiseng, Mohoto, Lieketso
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng , Mohoto, Lieketso
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298663 , vital:57725 , xlink:href="https://doi.org/10.1080/02589001.2021.1909711"
- Description: In Male Daughters, Female Husbands (1987) Amadiume argues that the female orientation of Nnobi society and its emphasis on female industriousness is ‘derived from goddess Idemili – the ancestral religious deity’ (27). While Christianity dominates the outlook and conservatism of the post-colonial African state, we are seeing a growing public presence of African spiritual practitioners in southern Africa. The interview with Lieketso Gogo Mapitsi Mohoto reflects on her journey of becoming a healer. She uses the concept of ‘uvalo' to argue for deeper connected spiritual awareness within this practice of healing. Using the Nguni concept of uvalo, she refers to the fluid meaning of intuition also known as Umbilini among Xhosa-speaking people, while Sesotho speakers call it Letswalo. This intimate connection with the Divine can sometimes mean a sense of fear for ordinary people, while it promotes a deep sense of knowing for the spiritually conscious. Gogo Mapitsi's connections between spirituality and land, speak to Amadiume’s matrifocal understanding of productivity as linked to the goddess Idemili in Nnobi histories. Gogo Mapitsi reminds us that the multiple health, economic, psychological crises we face today are linked 'to how uvalo works.' She tells us that the 'cultivation of that inner knowing and the cultivation of trust in that knowing' is central to how a Sangoma understands and responds to the needs of their society.
- Full Text:
- Date Issued: 2021
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng , Mohoto, Lieketso
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298663 , vital:57725 , xlink:href="https://doi.org/10.1080/02589001.2021.1909711"
- Description: In Male Daughters, Female Husbands (1987) Amadiume argues that the female orientation of Nnobi society and its emphasis on female industriousness is ‘derived from goddess Idemili – the ancestral religious deity’ (27). While Christianity dominates the outlook and conservatism of the post-colonial African state, we are seeing a growing public presence of African spiritual practitioners in southern Africa. The interview with Lieketso Gogo Mapitsi Mohoto reflects on her journey of becoming a healer. She uses the concept of ‘uvalo' to argue for deeper connected spiritual awareness within this practice of healing. Using the Nguni concept of uvalo, she refers to the fluid meaning of intuition also known as Umbilini among Xhosa-speaking people, while Sesotho speakers call it Letswalo. This intimate connection with the Divine can sometimes mean a sense of fear for ordinary people, while it promotes a deep sense of knowing for the spiritually conscious. Gogo Mapitsi's connections between spirituality and land, speak to Amadiume’s matrifocal understanding of productivity as linked to the goddess Idemili in Nnobi histories. Gogo Mapitsi reminds us that the multiple health, economic, psychological crises we face today are linked 'to how uvalo works.' She tells us that the 'cultivation of that inner knowing and the cultivation of trust in that knowing' is central to how a Sangoma understands and responds to the needs of their society.
- Full Text:
- Date Issued: 2021
Skills for communicating severe acute respiratory syndrome-coronavirus-2 result to patients and/or relatives
- Adeniyi, Oladele Vincent, Kayembe, Dominique K
- Authors: Adeniyi, Oladele Vincent , Kayembe, Dominique K
- Date: 2021
- Subjects: COVID-19 Structured model Medical consultation Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7236 , vital:53095 , xlink:href="https://doi.org/10.4102/safp.v63i1.5221"
- Description: Clinicians notify positive results of the severe acute respiratory syndrome coronavirus-2 polymerase chain reaction to patients and/or relatives, whilst short message service (SMS) has been adopted as a means of disseminating negative results. Therefore, clinicians should be adequately equipped to provide telephonic consultation whilst delivering a positive test result to patients. The news of the coronavirus disease 2019 (COVID-19) test result often invokes fear of impending death in patients, especially the elderlies and those with comorbidities. In addition, several survivors have reported persistent symptoms and COVID-19-related stigma, which precludes them from immediate re-integration into their workplaces. Consequently, COVID-19 results are perceived as bad news by the members of the public. This article justifies why COVID-19 test results are bad news and also discusses the notification steps to follow when delivering COVID-19 results, whilst also addressing patients’ immediate concerns. The article concludes by highlighting an important safety net for COVID-19 patients and the attending clinician.
- Full Text:
- Date Issued: 2021
- Authors: Adeniyi, Oladele Vincent , Kayembe, Dominique K
- Date: 2021
- Subjects: COVID-19 Structured model Medical consultation Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7236 , vital:53095 , xlink:href="https://doi.org/10.4102/safp.v63i1.5221"
- Description: Clinicians notify positive results of the severe acute respiratory syndrome coronavirus-2 polymerase chain reaction to patients and/or relatives, whilst short message service (SMS) has been adopted as a means of disseminating negative results. Therefore, clinicians should be adequately equipped to provide telephonic consultation whilst delivering a positive test result to patients. The news of the coronavirus disease 2019 (COVID-19) test result often invokes fear of impending death in patients, especially the elderlies and those with comorbidities. In addition, several survivors have reported persistent symptoms and COVID-19-related stigma, which precludes them from immediate re-integration into their workplaces. Consequently, COVID-19 results are perceived as bad news by the members of the public. This article justifies why COVID-19 test results are bad news and also discusses the notification steps to follow when delivering COVID-19 results, whilst also addressing patients’ immediate concerns. The article concludes by highlighting an important safety net for COVID-19 patients and the attending clinician.
- Full Text:
- Date Issued: 2021
Solar Driven Photocatalytic Activity of Porphyrin Sensitized TiO2
- Otieno, Sebastien, Lanterna, Anabel E, Mack, John, Derese, Solomon, Amuhaya, Edith K, Nyokong, Tebello, Scaiano, Juan C
- Authors: Otieno, Sebastien , Lanterna, Anabel E , Mack, John , Derese, Solomon , Amuhaya, Edith K , Nyokong, Tebello , Scaiano, Juan C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190612 , vital:45010 , xlink:href="https://doi.org/10.3390/molecules26113131"
- Description: The absence of a secure long-term sustainable energy supply is recognized as a major worldwide technological challenge. The generation of H2 through photocatalysis is an environmentally friendly alternative that can help solve the energy problem. Thus, the development of semiconductor materials that can absorb solar light is an attractive approach. TiO2 has a wide bandgap that suffers from no activity in the visible spectrum, limiting its use of solar radiation. In this research, the semiconductor absorption profile was extended into the visible region of the solar spectrum by preparing porphyrin-TiO2 (P-TiO2 ) composites of meso-tetra(4-bromophenyl)porphyrin (PP1) and meso-tetra(5-bromo-2-thienyl)porphyrin (PP2) and their In(III), Zn(II) and Ga(III) metal complexes. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed on the porphyrins to gain insight into their electron injection capability. The results demonstrate that P-TiO2 systems merit further in-depth study for applications that require efficient photocatalytic H2 generation.
- Full Text:
- Date Issued: 2021
- Authors: Otieno, Sebastien , Lanterna, Anabel E , Mack, John , Derese, Solomon , Amuhaya, Edith K , Nyokong, Tebello , Scaiano, Juan C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190612 , vital:45010 , xlink:href="https://doi.org/10.3390/molecules26113131"
- Description: The absence of a secure long-term sustainable energy supply is recognized as a major worldwide technological challenge. The generation of H2 through photocatalysis is an environmentally friendly alternative that can help solve the energy problem. Thus, the development of semiconductor materials that can absorb solar light is an attractive approach. TiO2 has a wide bandgap that suffers from no activity in the visible spectrum, limiting its use of solar radiation. In this research, the semiconductor absorption profile was extended into the visible region of the solar spectrum by preparing porphyrin-TiO2 (P-TiO2 ) composites of meso-tetra(4-bromophenyl)porphyrin (PP1) and meso-tetra(5-bromo-2-thienyl)porphyrin (PP2) and their In(III), Zn(II) and Ga(III) metal complexes. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were performed on the porphyrins to gain insight into their electron injection capability. The results demonstrate that P-TiO2 systems merit further in-depth study for applications that require efficient photocatalytic H2 generation.
- Full Text:
- Date Issued: 2021
Specialty Grand Challenges in Urban Agriculture: Ecological and Social Approaches to Sustainability Transformations
- Zimmerer, Karl S, Bell, Martha G, Chirisa, Innocent, Duvall, Chris S, Egerer, Monika, Hung, Po-Yi, Lerner, Amy M, Shackleton, Charlie M, Ward, James David, Yacamán Ochoa, Carolina
- Authors: Zimmerer, Karl S , Bell, Martha G , Chirisa, Innocent , Duvall, Chris S , Egerer, Monika , Hung, Po-Yi , Lerner, Amy M , Shackleton, Charlie M , Ward, James David , Yacamán Ochoa, Carolina
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175779 , vital:42623 , https://doi.org/10.3389/fsufs.2021.668561
- Description: This synopsis of the Grand Challenges of Urban Agriculture (UA) is framed by the urgent need to understand and strengthen the expanding yet highly diverse roles of UA amid rapid global urbanization, failures of predominant food systems, and crises in systems of physical and mental health. More than half of humanity lives in cities today and by 2030 this is projected to grow to 60.4 percent, ~5 billion people (UN Habitat, 2020). More than 90 percent of urban demographic increase is anticipated to take place in the developing world.
- Full Text:
- Date Issued: 2021
- Authors: Zimmerer, Karl S , Bell, Martha G , Chirisa, Innocent , Duvall, Chris S , Egerer, Monika , Hung, Po-Yi , Lerner, Amy M , Shackleton, Charlie M , Ward, James David , Yacamán Ochoa, Carolina
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175779 , vital:42623 , https://doi.org/10.3389/fsufs.2021.668561
- Description: This synopsis of the Grand Challenges of Urban Agriculture (UA) is framed by the urgent need to understand and strengthen the expanding yet highly diverse roles of UA amid rapid global urbanization, failures of predominant food systems, and crises in systems of physical and mental health. More than half of humanity lives in cities today and by 2030 this is projected to grow to 60.4 percent, ~5 billion people (UN Habitat, 2020). More than 90 percent of urban demographic increase is anticipated to take place in the developing world.
- Full Text:
- Date Issued: 2021
Strategies utilised in translating children’s stories from English into isiXhosa
- Authors: Madolo, Yolisa
- Date: 2021
- Subjects: Children Xhosa Grammar, Comparative and general--Ideophone Children, Black, in literature Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7010 , vital:52637 , xlink:href="https://doi.org/10.1080/02572117.2021.2010919"
- Description: Translation scholars suggest various strategies for dealing with equivalence and non-equivalence. These popular strategies address non-equivalence, the converse of equivalence, that is commonly found in translation. Nonequivalence is found at word, phrase, sentence, and pragmatic levels. Not a great deal of research has been done in the translation strategies used between English and South African indigenous languages. It is possible that these languages employ some strategies that are not listed under current, popular strategies. These strategies may be necessitated by the linguistic and historical differences between English and African languages. For instance, what is acceptable in question form in English might be more suitable as a statement in African languages, specifically isiXhosa. The strategies to be presented are from an ongoing study of selected children’s stories translated from English into isiXhosa. The aim of the study is to scrutinise some of the strategies used by the translators in their translations. Preliminary results reveal that translators from English into isiXhosa may explicitate or implicitate the translation using various strategies like addition, infusing target language culture, translating source language idiom by another figure of speech or even omitting some words. This may have minimal or significant impact on the transferred message.
- Full Text:
- Date Issued: 2021
- Authors: Madolo, Yolisa
- Date: 2021
- Subjects: Children Xhosa Grammar, Comparative and general--Ideophone Children, Black, in literature Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7010 , vital:52637 , xlink:href="https://doi.org/10.1080/02572117.2021.2010919"
- Description: Translation scholars suggest various strategies for dealing with equivalence and non-equivalence. These popular strategies address non-equivalence, the converse of equivalence, that is commonly found in translation. Nonequivalence is found at word, phrase, sentence, and pragmatic levels. Not a great deal of research has been done in the translation strategies used between English and South African indigenous languages. It is possible that these languages employ some strategies that are not listed under current, popular strategies. These strategies may be necessitated by the linguistic and historical differences between English and African languages. For instance, what is acceptable in question form in English might be more suitable as a statement in African languages, specifically isiXhosa. The strategies to be presented are from an ongoing study of selected children’s stories translated from English into isiXhosa. The aim of the study is to scrutinise some of the strategies used by the translators in their translations. Preliminary results reveal that translators from English into isiXhosa may explicitate or implicitate the translation using various strategies like addition, infusing target language culture, translating source language idiom by another figure of speech or even omitting some words. This may have minimal or significant impact on the transferred message.
- Full Text:
- Date Issued: 2021
Sustainable Human Resource Practices for Organizational Competitiveness Post the Covid-19 Pandemic
- Asoba, Samson Nambei, Patricia, Nteboheng Mefi
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Personel Management Covid-19 (Disease) Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8118 , vital:61396 , xlink:href="https://www.abacademies.org/articles/Sustainable-human-resource-practices-for-organizational-competitiveness-post-the-covid-19-1528-2686-27-2-480.pdf"
- Description: The study was formulated to tap into the future of HRM given the disruptions arising from the Covid-119 pandemic as well as the progression of the global technological environment to the fourth industrial revolution. The aim of the study was to: the Covid-19 induced HRM practices underpinning future organizational competitiveness. A literature review strategy was adopted to achieve the study objective. The study established seven emerging themes to inform HRM practices for the competitiveness of organizations in future following the Covid-19 disturbances. These themes are: primacy of HRM, increased cyber influences, digitalization, remote HRM, human-machine interface skills, human-organisation strategic links as well as human-technology interface competencies. Based on the study findings, the study recommended HRM departments to move to HR 4.0 through the adoption of industry 4.0 technologies, increased automation, and digitalization as well as strengthen virtualization systems.
- Full Text:
- Date Issued: 2021
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Personel Management Covid-19 (Disease) Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8118 , vital:61396 , xlink:href="https://www.abacademies.org/articles/Sustainable-human-resource-practices-for-organizational-competitiveness-post-the-covid-19-1528-2686-27-2-480.pdf"
- Description: The study was formulated to tap into the future of HRM given the disruptions arising from the Covid-119 pandemic as well as the progression of the global technological environment to the fourth industrial revolution. The aim of the study was to: the Covid-19 induced HRM practices underpinning future organizational competitiveness. A literature review strategy was adopted to achieve the study objective. The study established seven emerging themes to inform HRM practices for the competitiveness of organizations in future following the Covid-19 disturbances. These themes are: primacy of HRM, increased cyber influences, digitalization, remote HRM, human-machine interface skills, human-organisation strategic links as well as human-technology interface competencies. Based on the study findings, the study recommended HRM departments to move to HR 4.0 through the adoption of industry 4.0 technologies, increased automation, and digitalization as well as strengthen virtualization systems.
- Full Text:
- Date Issued: 2021
Synthesis of a near infrared-actuated phthalocyanine-lipid vesicle system for augmented photodynamic therapy
- Nwahara, Namdi, Managa, Muthumuni, Stoffels, Mihlali, Britton, Jonathan, Prinsloo, Earl, Nyokong, Tebello
- Authors: Nwahara, Namdi , Managa, Muthumuni , Stoffels, Mihlali , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185395 , vital:44383 , xlink:href="https://doi.org/10.1016/j.synthmet.2021.116811"
- Description: The efficacy of photodynamic therapy (PDT) is often limited by the poor bio-distributive properties of conventional photosensitizers and the local hypoxic microenvironment that characterises most solid tumours. Herein, a novel in situ oxygenic lipid formulation for photodynamic therapy (PDT) is reported. Such a hybrid was synthesized by adsorbing bimetallic nanozyme, MnO2@PtNPs (NPs = nanoparticles) onto graphene quantum dots (GQDs) – zinc (II) phthalocyanine conjugates, followed by liposomal encapsulation, affording it enhanced water solubility. The MnO2@PtNPs, which are is shown to possess excellent catalase-like properties surpassing that of MnO2 or PtNPs alone, serves to catalyze H2O2 to O2, while the zinc (II) phthalocyanine (1) serves to transform the formed oxygen to generate cytotoxic singlet oxygen immediately. We show that by combining each function of the respective building blocks, the as-synthesized 1-GQDs-MnO2@PtNPs-liposomes not only maintains the properties of oxygen supplementation through H2O2 catalysis but also displays cooperative properties for enhanced singlet oxygen production. Consequently, a remarkably improved PDT efficacy was observed for 1-GQDs-MnO2@PtNPs-liposomes in both normoxia and hypoxia. These results demonstrate the potential applicability of such nanozyme constituted 1-GQDs-MnO2@PtNPs-liposomes for achieving tumour treatment in hypoxic conditions by PDT.
- Full Text:
- Date Issued: 2021
- Authors: Nwahara, Namdi , Managa, Muthumuni , Stoffels, Mihlali , Britton, Jonathan , Prinsloo, Earl , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185395 , vital:44383 , xlink:href="https://doi.org/10.1016/j.synthmet.2021.116811"
- Description: The efficacy of photodynamic therapy (PDT) is often limited by the poor bio-distributive properties of conventional photosensitizers and the local hypoxic microenvironment that characterises most solid tumours. Herein, a novel in situ oxygenic lipid formulation for photodynamic therapy (PDT) is reported. Such a hybrid was synthesized by adsorbing bimetallic nanozyme, MnO2@PtNPs (NPs = nanoparticles) onto graphene quantum dots (GQDs) – zinc (II) phthalocyanine conjugates, followed by liposomal encapsulation, affording it enhanced water solubility. The MnO2@PtNPs, which are is shown to possess excellent catalase-like properties surpassing that of MnO2 or PtNPs alone, serves to catalyze H2O2 to O2, while the zinc (II) phthalocyanine (1) serves to transform the formed oxygen to generate cytotoxic singlet oxygen immediately. We show that by combining each function of the respective building blocks, the as-synthesized 1-GQDs-MnO2@PtNPs-liposomes not only maintains the properties of oxygen supplementation through H2O2 catalysis but also displays cooperative properties for enhanced singlet oxygen production. Consequently, a remarkably improved PDT efficacy was observed for 1-GQDs-MnO2@PtNPs-liposomes in both normoxia and hypoxia. These results demonstrate the potential applicability of such nanozyme constituted 1-GQDs-MnO2@PtNPs-liposomes for achieving tumour treatment in hypoxic conditions by PDT.
- Full Text:
- Date Issued: 2021
Synthesis, spectroscopic and nonlinear optical properties of asymmetric A3B type phthalocyanine complexes
- Authors: Mugeza, Rhulani Donney
- Date: 2021
- Subjects: Spectrum analysis , Mass spectrometry , Phthalocyanines
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171667 , vital:42108
- Description: This work reports on the synthesis of symmetrical and asymmetrical A 3 B type metal free, cobalt and zinc Phthalocyanines (Pc) .A wide range of spectroscopic techniques such as Uv - visible absorption (UV), magnetic circular dichroism (MCD), mass spectrometry, elemental analysis, IR spectroscopy and time correlated single photo n counting spectroscopy (TCSPC) have been used to study the spectroscopic properties of the phthalocyanine complexes. The Z - scan technique was used to comparatively investigate the nonlinear absorption coefficient ( 휷 ) and the nonlinear refraction index ( 풏 ퟐ ) of the synthesized complexes. The following trend was obtained for the synthesized Pc’s in terms of the 휷 values 7.25 × 10 − 10 ( 4b ) > 3.76 × 10 − 10 ( 4a ) > 3.52 × 10 − 10 ( 4c ) > 2.29 × 10 − 10 ( 3c ) > 1.68 × 10 − 10 ( 3a ) > 1.65 × 10 − 10 ( 3b ) mW - 1 . The 휷 values trend of synthesized Pc complexes show that the asymmetrical A 3 B type metal free, cobalt and zinc Pc complexes ( 4a , 4b and 4c ) have larger 휷 values as compared to the octa - substituted symmetrical metal free, cobalt and zinc Pc complexes ( 3a , 3b and 3c ) which is attributed to the low symmetry of the Pc complexes. The five - level model rate equations were used to determine the two photon absorption, excited state absorption and ground state absorption cross sections of the synthesized complexes. The z inc A 3 B type asymmetrical Pc complexes gave the largest two photon absorption and 휎 푒 / 휎 푔 ratio values. This Pc complex could be used in future work to enhance the nonlinear response further by introducing nanomaterials and converting the Pc complex to a binuclear Pc. This work also reports on the density functional theory (DFT) calculations o f dipolar/octupolar contributions in order to study the first order hyperpolarizability of the synthesized Pc complexes.
- Full Text:
- Date Issued: 2021
- Authors: Mugeza, Rhulani Donney
- Date: 2021
- Subjects: Spectrum analysis , Mass spectrometry , Phthalocyanines
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171667 , vital:42108
- Description: This work reports on the synthesis of symmetrical and asymmetrical A 3 B type metal free, cobalt and zinc Phthalocyanines (Pc) .A wide range of spectroscopic techniques such as Uv - visible absorption (UV), magnetic circular dichroism (MCD), mass spectrometry, elemental analysis, IR spectroscopy and time correlated single photo n counting spectroscopy (TCSPC) have been used to study the spectroscopic properties of the phthalocyanine complexes. The Z - scan technique was used to comparatively investigate the nonlinear absorption coefficient ( 휷 ) and the nonlinear refraction index ( 풏 ퟐ ) of the synthesized complexes. The following trend was obtained for the synthesized Pc’s in terms of the 휷 values 7.25 × 10 − 10 ( 4b ) > 3.76 × 10 − 10 ( 4a ) > 3.52 × 10 − 10 ( 4c ) > 2.29 × 10 − 10 ( 3c ) > 1.68 × 10 − 10 ( 3a ) > 1.65 × 10 − 10 ( 3b ) mW - 1 . The 휷 values trend of synthesized Pc complexes show that the asymmetrical A 3 B type metal free, cobalt and zinc Pc complexes ( 4a , 4b and 4c ) have larger 휷 values as compared to the octa - substituted symmetrical metal free, cobalt and zinc Pc complexes ( 3a , 3b and 3c ) which is attributed to the low symmetry of the Pc complexes. The five - level model rate equations were used to determine the two photon absorption, excited state absorption and ground state absorption cross sections of the synthesized complexes. The z inc A 3 B type asymmetrical Pc complexes gave the largest two photon absorption and 휎 푒 / 휎 푔 ratio values. This Pc complex could be used in future work to enhance the nonlinear response further by introducing nanomaterials and converting the Pc complex to a binuclear Pc. This work also reports on the density functional theory (DFT) calculations o f dipolar/octupolar contributions in order to study the first order hyperpolarizability of the synthesized Pc complexes.
- Full Text:
- Date Issued: 2021