Declines in Livestock Numbers Accompany Cropping Deagrarianisation Processes in the Eastern Cape, South Africa
- Shackleton, Charlie M, Ntshudu, Monde
- Authors: Shackleton, Charlie M , Ntshudu, Monde
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402248 , vital:69834 , xlink:href="https://doi.org/10.3390/land12091735"
- Description: Deagrarianisation amongst smallholder farmers is a growing phenomenon globally, driven by a complex array of context-specific and higher-scale factors. Most research has focused on declines in arable cropping, with relatively little regard to the deagrarianisation dynamics associated with livestock ownership, yet the two are often linked through the need for draught power for ploughing. Here, we report on a survey of 293 rural households in 10 rural villages in the Eastern Cape province, South Africa, where we ascertained whether ownership of cattle, goats, sheep and pigs had changed over the previous 15 years and what were the underlying reasons for any changes at both village- and household-scale. The majority felt that there had been a decline in the number of households keeping livestock and the number of animals in the village. Additionally, a clear majority of owners for each type of livestock stated that their households currently have fewer animals than 15 years ago. The main reasons for declines were that their animals had died due to drought or disease, theft, or they had sold them because of financial needs. There was a positive association between the keeping of cattle and field cultivation. Despite these general declines, two-thirds of households currently without livestock wished that they had some, primarily for use in cultural ceremonies/rituals or for income. This study shows the deagrarianisation processes in the region also apply to the livestock sector despite the significance of livestock in the local Xhosa culture. This study highlights the multifaceted nature of deagrarianisation in communal tenure systems.
- Full Text:
- Date Issued: 2023
- Authors: Shackleton, Charlie M , Ntshudu, Monde
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402248 , vital:69834 , xlink:href="https://doi.org/10.3390/land12091735"
- Description: Deagrarianisation amongst smallholder farmers is a growing phenomenon globally, driven by a complex array of context-specific and higher-scale factors. Most research has focused on declines in arable cropping, with relatively little regard to the deagrarianisation dynamics associated with livestock ownership, yet the two are often linked through the need for draught power for ploughing. Here, we report on a survey of 293 rural households in 10 rural villages in the Eastern Cape province, South Africa, where we ascertained whether ownership of cattle, goats, sheep and pigs had changed over the previous 15 years and what were the underlying reasons for any changes at both village- and household-scale. The majority felt that there had been a decline in the number of households keeping livestock and the number of animals in the village. Additionally, a clear majority of owners for each type of livestock stated that their households currently have fewer animals than 15 years ago. The main reasons for declines were that their animals had died due to drought or disease, theft, or they had sold them because of financial needs. There was a positive association between the keeping of cattle and field cultivation. Despite these general declines, two-thirds of households currently without livestock wished that they had some, primarily for use in cultural ceremonies/rituals or for income. This study shows the deagrarianisation processes in the region also apply to the livestock sector despite the significance of livestock in the local Xhosa culture. This study highlights the multifaceted nature of deagrarianisation in communal tenure systems.
- Full Text:
- Date Issued: 2023
Dual action of asymmetrical zinc (II) phthalocyanines conjugated to silver tungstate nanoparticles towards photodegradation of tetracycline and inactivation of Staphylococcus aureus bacteria
- Mgidlana, Sithi, Sen, Pinar, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
- Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
- Full Text:
- Date Issued: 2023
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
- Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
- Full Text:
- Date Issued: 2023
Fabrication of asymmetrical morpholine phthalocyanines conjugated chitosan-polyacrylonitrile nanofibers for improved photodynamic antimicrobial chemotherapy activity
- Sindelo, Azole, Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229873 , vital:49719 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102760"
- Description: The work is based on the synthesis and photodynamic antimicrobial chemotherapy (PACT) activities of neutral (1 and 2) and cationic (1Q and 2Q) morpholine substituted phthalocyanines. For applicability, these complexes were covalently linked to modified polyacrylonitrile (PAN) to form 1-PAN, 2-PAN, 1Q-PAN, and 2Q-PAN, respectively. Chitosan was conjugated to PAN (to form PAN-CS) which was then linked to the Pcs to form PAN-CS-1, PAN-CS-2, PAN-CS-1Q, and PAN-CS-2Q, respectively. Singlet oxygen quantum yields improved following the inclusion of chitosan. The PACT activities of the complexes alone and when anchored to both PAN and PAN-CS was evaluated against bacteria: S. aureus, E. coli and fungi C. albicans. Cationic phthalocyanine showed high efficacy values of >7 log reduction value for all microorganisms. These results translated into excellent bacterial colony reduction of >90% against both S. aureus and C. albicans after 1 h of photoirradiation on PAN-CS support.
- Full Text:
- Date Issued: 2022
- Authors: Sindelo, Azole , Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229873 , vital:49719 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102760"
- Description: The work is based on the synthesis and photodynamic antimicrobial chemotherapy (PACT) activities of neutral (1 and 2) and cationic (1Q and 2Q) morpholine substituted phthalocyanines. For applicability, these complexes were covalently linked to modified polyacrylonitrile (PAN) to form 1-PAN, 2-PAN, 1Q-PAN, and 2Q-PAN, respectively. Chitosan was conjugated to PAN (to form PAN-CS) which was then linked to the Pcs to form PAN-CS-1, PAN-CS-2, PAN-CS-1Q, and PAN-CS-2Q, respectively. Singlet oxygen quantum yields improved following the inclusion of chitosan. The PACT activities of the complexes alone and when anchored to both PAN and PAN-CS was evaluated against bacteria: S. aureus, E. coli and fungi C. albicans. Cationic phthalocyanine showed high efficacy values of >7 log reduction value for all microorganisms. These results translated into excellent bacterial colony reduction of >90% against both S. aureus and C. albicans after 1 h of photoirradiation on PAN-CS support.
- Full Text:
- Date Issued: 2022
From affirmative to transformative approaches to academic development
- McKenna, Sioux, Hlengwa, Amanda, Quinn, Lyn, Vorster, Jo-Anne
- Authors: McKenna, Sioux , Hlengwa, Amanda , Quinn, Lyn , Vorster, Jo-Anne
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426651 , vital:72375 , xlink:href="https://doi.org/10.1080/13562517.2022.2119077"
- Description: Much academic development work, whether it be student, academic staff, institutional or curriculum development, is undertaken from an affirmative rather than a transformative approach (Luckett, L., and S. Shay. 2020.“Reframing the Curriculum: A Transformative Approach.” Critical Studies in Education61 (1): 50–65). To be transformative, academic development has to reframe the problem beyond one of poor student retention and throughput. We need to make sense of the conditions from which issues such as poor retention and throughput rates emerge, rather than focusing on mitigating the effects of such conditions within the status quo. Drawing on Fraser’s concept of parity of participation, we suggest that if academic development is to engage in transformative approaches, it needs to adjust the scale of the problem and challenge underpinning assumptions, and thereby review the fitness of universities, curricula and academic development practices for a pluralist society. In sum, a transformative approach to academic development work will entail conceptualising academic development as a political knowledge project.
- Full Text:
- Date Issued: 2022
- Authors: McKenna, Sioux , Hlengwa, Amanda , Quinn, Lyn , Vorster, Jo-Anne
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426651 , vital:72375 , xlink:href="https://doi.org/10.1080/13562517.2022.2119077"
- Description: Much academic development work, whether it be student, academic staff, institutional or curriculum development, is undertaken from an affirmative rather than a transformative approach (Luckett, L., and S. Shay. 2020.“Reframing the Curriculum: A Transformative Approach.” Critical Studies in Education61 (1): 50–65). To be transformative, academic development has to reframe the problem beyond one of poor student retention and throughput. We need to make sense of the conditions from which issues such as poor retention and throughput rates emerge, rather than focusing on mitigating the effects of such conditions within the status quo. Drawing on Fraser’s concept of parity of participation, we suggest that if academic development is to engage in transformative approaches, it needs to adjust the scale of the problem and challenge underpinning assumptions, and thereby review the fitness of universities, curricula and academic development practices for a pluralist society. In sum, a transformative approach to academic development work will entail conceptualising academic development as a political knowledge project.
- Full Text:
- Date Issued: 2022
From imperialism to radical hospitality: propositions for reconfiguring social work towards a justice-to-come
- Bozalek, Vivienne, Holscher, Dorothee
- Authors: Bozalek, Vivienne , Holscher, Dorothee
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426904 , vital:72399 , xlink:href="https://doi.org/10.25159/2708-9355/8889"
- Description: The focus of the article is on injustices towards South African families in postcolonial and neocolonial contexts, our understanding of which has been greatly enlarged by Nancy Fraser’s conceptualisations of expropriation and imperialism and Jacques Derrida’s notions of hostility and hospitality. We used Walter Benjamin’s and Karen Barad’s montage methods of fragmentary writing to diffractively read expropriation, imperialism, hostility and hospitality through one another in the context of injustices done to South African families. A diffractive methodology entails a close and attentive reading of concepts or pieces of text through one another, to arrive at new insights with regard to a particular issue. The new insights we arrive at in the article are five propositions for ethically engaging in a justice-to-come for social work – that of attentiveness, rendering each other capable, responsibility, response-ability and radical hospitality.
- Full Text:
- Date Issued: 2022
- Authors: Bozalek, Vivienne , Holscher, Dorothee
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426904 , vital:72399 , xlink:href="https://doi.org/10.25159/2708-9355/8889"
- Description: The focus of the article is on injustices towards South African families in postcolonial and neocolonial contexts, our understanding of which has been greatly enlarged by Nancy Fraser’s conceptualisations of expropriation and imperialism and Jacques Derrida’s notions of hostility and hospitality. We used Walter Benjamin’s and Karen Barad’s montage methods of fragmentary writing to diffractively read expropriation, imperialism, hostility and hospitality through one another in the context of injustices done to South African families. A diffractive methodology entails a close and attentive reading of concepts or pieces of text through one another, to arrive at new insights with regard to a particular issue. The new insights we arrive at in the article are five propositions for ethically engaging in a justice-to-come for social work – that of attentiveness, rendering each other capable, responsibility, response-ability and radical hospitality.
- Full Text:
- Date Issued: 2022
Fuelwood in South Africa Revisited: Widespread Use in a Policy Vacuum
- Shackleton, Charlie M, Sinasson, Gisele, Adeyemi, Opeyemi, Martins, Vusumzi
- Authors: Shackleton, Charlie M , Sinasson, Gisele , Adeyemi, Opeyemi , Martins, Vusumzi
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402275 , vital:69837 , xlink:href="https://doi.org/10.3390/su141711018"
- Description: South Africa has experienced massive urbanisation and socioeconomic development over the past two decades. Concomitantly, the national energy policy focuses on the provision of modern fuels, notably electricity, for domestic use. Given this policy environment and socioeconomic development, we examine pertinent literature and policies from South Africa on fuelwood use, value, and sustainability to understand how it might have changed in tandem with the national shifts in urbanisation and socioeconomic development over the last 20 years. Recent literature shows that fuelwood is still used to some extent by 96% of rural households and 69% of low-income urban ones. We also estimate that the use of fuelwood by rural households alone is valued at approximately ZAR 10.5 billion (approx. USD 700 million) annually, with the probability of an equally high value to low-income urban households. However, despite the extensive use and high value, our analysis of cognate national policies related to energy, forestry, environment, and social development, show that fuelwood and its use is hardly considered, indicating a policy vacuum. This policy vacuum means that there is no strategic or apposite support or interventions in any localised areas where fuelwood demand might exceed supply, thereby undermining the livelihoods and energy security of affected citizens, most notably the poor.
- Full Text:
- Date Issued: 2022
- Authors: Shackleton, Charlie M , Sinasson, Gisele , Adeyemi, Opeyemi , Martins, Vusumzi
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402275 , vital:69837 , xlink:href="https://doi.org/10.3390/su141711018"
- Description: South Africa has experienced massive urbanisation and socioeconomic development over the past two decades. Concomitantly, the national energy policy focuses on the provision of modern fuels, notably electricity, for domestic use. Given this policy environment and socioeconomic development, we examine pertinent literature and policies from South Africa on fuelwood use, value, and sustainability to understand how it might have changed in tandem with the national shifts in urbanisation and socioeconomic development over the last 20 years. Recent literature shows that fuelwood is still used to some extent by 96% of rural households and 69% of low-income urban ones. We also estimate that the use of fuelwood by rural households alone is valued at approximately ZAR 10.5 billion (approx. USD 700 million) annually, with the probability of an equally high value to low-income urban households. However, despite the extensive use and high value, our analysis of cognate national policies related to energy, forestry, environment, and social development, show that fuelwood and its use is hardly considered, indicating a policy vacuum. This policy vacuum means that there is no strategic or apposite support or interventions in any localised areas where fuelwood demand might exceed supply, thereby undermining the livelihoods and energy security of affected citizens, most notably the poor.
- Full Text:
- Date Issued: 2022
Interaction between an entomopathogenic fungus and entomopathogenic nematodes for increased mortality of Thaumatotibia leucotreta (Lepidoptera: Tortricidae)
- Prinsloo, Sandra, Hill, Martin P, Moore, Sean D, Malan, Antoinette P, Coombes, Candice A
- Authors: Prinsloo, Sandra , Hill, Martin P , Moore, Sean D , Malan, Antoinette P , Coombes, Candice A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417738 , vital:71482 , xlink:href="https://doi.org/10.1080/09583157.2022.2099528"
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a major phytosanitary pest of citrus in South Africa. Although several management tools exist, control options registered for use against the soil-dwelling life stages are limited. Both entomopathogenic nematodes (EPNs) and entomopathogenic fungi have been investigated previously, but they have not been studied in combination against T. leucotreta. Thus, this study investigated the interaction of an indigenous entomopathogenic fungus, Metarhizium pinghaense (previously anisopliae) FCM Ar 23 B3 with three indigenous EPNs: Steinernema yirgalemense 157-C, S. jeffreyense J194 and Heterorhabditis noenieputensis 158-C for increased late instar T. leucotreta larval mortality. Before interaction experiments, lethal concentration (LC) values for each of these microbial agents were determined through dose–response bioassays. Heterorhabditis noenieputensis recorded the highest LC50 amongst the nematodes (7.11 IJs/50 µl). Using the pre-determined LC70 value of M. pinghaense and the LC50 values for each of the nematode species, interaction experiments were conducted. Combinations of the nematodes either applied simultaneously with the fungus or at 24, 48, 72 or 96 h post-fungal application showed predominantly additive interactions. Synergy between the simultaneous application of S. yirgalemense and M. pinghaense was found, whilst the interaction between H. noenieputensis and M. pinghaense applied simultaneously and S. jeffreyense applied 24 h post-fungal application, recorded antagonistic interactions. The use of these agents in combination may therefore have the potential to increase control of T. leucotreta soil-dwelling life stages in citrus orchards across South Africa and should be further investigated.
- Full Text:
- Date Issued: 2022
- Authors: Prinsloo, Sandra , Hill, Martin P , Moore, Sean D , Malan, Antoinette P , Coombes, Candice A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417738 , vital:71482 , xlink:href="https://doi.org/10.1080/09583157.2022.2099528"
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a major phytosanitary pest of citrus in South Africa. Although several management tools exist, control options registered for use against the soil-dwelling life stages are limited. Both entomopathogenic nematodes (EPNs) and entomopathogenic fungi have been investigated previously, but they have not been studied in combination against T. leucotreta. Thus, this study investigated the interaction of an indigenous entomopathogenic fungus, Metarhizium pinghaense (previously anisopliae) FCM Ar 23 B3 with three indigenous EPNs: Steinernema yirgalemense 157-C, S. jeffreyense J194 and Heterorhabditis noenieputensis 158-C for increased late instar T. leucotreta larval mortality. Before interaction experiments, lethal concentration (LC) values for each of these microbial agents were determined through dose–response bioassays. Heterorhabditis noenieputensis recorded the highest LC50 amongst the nematodes (7.11 IJs/50 µl). Using the pre-determined LC70 value of M. pinghaense and the LC50 values for each of the nematode species, interaction experiments were conducted. Combinations of the nematodes either applied simultaneously with the fungus or at 24, 48, 72 or 96 h post-fungal application showed predominantly additive interactions. Synergy between the simultaneous application of S. yirgalemense and M. pinghaense was found, whilst the interaction between H. noenieputensis and M. pinghaense applied simultaneously and S. jeffreyense applied 24 h post-fungal application, recorded antagonistic interactions. The use of these agents in combination may therefore have the potential to increase control of T. leucotreta soil-dwelling life stages in citrus orchards across South Africa and should be further investigated.
- Full Text:
- Date Issued: 2022
Livestock ecosystem services and disservices in a medium-sized South African town
- Thondhlana, Gladman, Papama, Yose, Cockburn, Jessica J, Shackleton, Charlie M
- Authors: Thondhlana, Gladman , Papama, Yose , Cockburn, Jessica J , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403241 , vital:69937 , xlink:href="https://doi.org/10.1080/26395916.2021.2019833"
- Description: Production of livestock in urban spaces is a common phenomenon globally, particularly in the Global South. Livestock provides multiple benefits to society yet its production in urban spaces can result in adverse impacts to residents that can trigger conflicts. Understanding of the ecosystem services and disservices of livestock from the perspectives of residents can inform inclusive local management plans. Using household surveys and key informant interviews, this study sought to examine the contribution of livestock to owners, and perceptions of livestock services and disservices among non-livestock owners and key informants in Makhanda, a medium-sized South African town. Livestock owners derived multiple benefits from their livestock, including provisioning services such as meat, milk, skins and draught, and use livestock and livestock products in cultural activities such as rituals, bride price payments and funerals that are key elements of local identity. Among residents, there were marked differences in perceptions on the services and disservices of livestock which points to potential conflicts over urban land use and the need for addressing trade-offs. A key trade-off for local municipal authorities is addressing hunger and poverty by supporting well-regulated urban livestock production versus managing potential livestock disservices such as injuries to humans, livestock-vehicle collisions, health hazards and damage to urban green infrastructure. The trade-offs should be understood and considered by local authorities and residents as a basis for collectively developing strategies that can integrate livelihoods and cultural realities to balance competing demands for urban spaces including livestock production and other uses.
- Full Text:
- Date Issued: 2022
- Authors: Thondhlana, Gladman , Papama, Yose , Cockburn, Jessica J , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403241 , vital:69937 , xlink:href="https://doi.org/10.1080/26395916.2021.2019833"
- Description: Production of livestock in urban spaces is a common phenomenon globally, particularly in the Global South. Livestock provides multiple benefits to society yet its production in urban spaces can result in adverse impacts to residents that can trigger conflicts. Understanding of the ecosystem services and disservices of livestock from the perspectives of residents can inform inclusive local management plans. Using household surveys and key informant interviews, this study sought to examine the contribution of livestock to owners, and perceptions of livestock services and disservices among non-livestock owners and key informants in Makhanda, a medium-sized South African town. Livestock owners derived multiple benefits from their livestock, including provisioning services such as meat, milk, skins and draught, and use livestock and livestock products in cultural activities such as rituals, bride price payments and funerals that are key elements of local identity. Among residents, there were marked differences in perceptions on the services and disservices of livestock which points to potential conflicts over urban land use and the need for addressing trade-offs. A key trade-off for local municipal authorities is addressing hunger and poverty by supporting well-regulated urban livestock production versus managing potential livestock disservices such as injuries to humans, livestock-vehicle collisions, health hazards and damage to urban green infrastructure. The trade-offs should be understood and considered by local authorities and residents as a basis for collectively developing strategies that can integrate livelihoods and cultural realities to balance competing demands for urban spaces including livestock production and other uses.
- Full Text:
- Date Issued: 2022
Not there yet: knowledge building in educational development ten years on
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426954 , vital:72403 , xlink:href="https://doi.org/10.1080/13562517.2022.2121158"
- Description: This paper responds to a question posed by [Shay, Suellen. 2012. “Educational Development as a Field: Are We There Yet?” Higher Education Research and Development 31 (3): 311–323. doii:10.1080/07294360.2011.631520] about the status of knowledge building in the field of Educational Development. In her paper, Shay critiques knowledge produced in the field arguing that it is ‘codified practice’ [Gamble, Jeanne. 2001. “Modelling the Invisible: The Pedagogy of Craft Apprenticeship.” Studies in Continuing Education 23 (2): 185–200. doii:10.1080/01580370120101957; Gamble, Jeanne. 2004. “Retrieving the General from the Particular: The Structure of Craft Knowledge.” In Reading Bernstein, Researching Bernstein, edited by J. Muller, B. Davies, and A. Morais, 189–203. Abingdon: Routledge; Gamble, Jeanne. 2006. “Theory and Practice in the Vocational Curriculum.” In Knowledge, Curriculum and Qualifications in South African Further Education, edited by M. Young and J. Gamble, 87–103. Pretoria: HSRC Press] rather than applied theory which could succeed in reconceptualising problems rather than simply trying to address them. This paper draws on a review of research produced in the field in recent years in South Africa to argue that, although some work does result in the reconceptualision of problems the higher education, it is limited in that (i) it has been produced by a relatively small group of practitioners located at a few universities and (ii) draws on theory developed in the Global North. The paper then proceeds to offer some tentative suggestions for the way future work aimed at knowledge building could proceed.
- Full Text:
- Date Issued: 2022
- Authors: Boughey, Chrissie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426954 , vital:72403 , xlink:href="https://doi.org/10.1080/13562517.2022.2121158"
- Description: This paper responds to a question posed by [Shay, Suellen. 2012. “Educational Development as a Field: Are We There Yet?” Higher Education Research and Development 31 (3): 311–323. doii:10.1080/07294360.2011.631520] about the status of knowledge building in the field of Educational Development. In her paper, Shay critiques knowledge produced in the field arguing that it is ‘codified practice’ [Gamble, Jeanne. 2001. “Modelling the Invisible: The Pedagogy of Craft Apprenticeship.” Studies in Continuing Education 23 (2): 185–200. doii:10.1080/01580370120101957; Gamble, Jeanne. 2004. “Retrieving the General from the Particular: The Structure of Craft Knowledge.” In Reading Bernstein, Researching Bernstein, edited by J. Muller, B. Davies, and A. Morais, 189–203. Abingdon: Routledge; Gamble, Jeanne. 2006. “Theory and Practice in the Vocational Curriculum.” In Knowledge, Curriculum and Qualifications in South African Further Education, edited by M. Young and J. Gamble, 87–103. Pretoria: HSRC Press] rather than applied theory which could succeed in reconceptualising problems rather than simply trying to address them. This paper draws on a review of research produced in the field in recent years in South Africa to argue that, although some work does result in the reconceptualision of problems the higher education, it is limited in that (i) it has been produced by a relatively small group of practitioners located at a few universities and (ii) draws on theory developed in the Global North. The paper then proceeds to offer some tentative suggestions for the way future work aimed at knowledge building could proceed.
- Full Text:
- Date Issued: 2022
Novel cationic-chalcone phthalocyanines for photodynamic therapy eradication of S. aureus and E. coli bacterial biofilms and MCF-7 breast cancer
- Openda, Yolande Ikala, Babu, Balaji, Nyokong, Tebello
- Authors: Openda, Yolande Ikala , Babu, Balaji , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300129 , vital:57895 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102863"
- Description: New tetrasubstituted zinc (II) and indium (III) phthalocyanines bearing dimethylamino chalcone group (complexes 3 and 4) as well as their quaternized analogs (3a and 4a) have been assessed for their photodynamic therapy (PDT) of cancer as well as photodynamic antimicrobial chemotherapy activities against biofilms and planktonic cultures of pathogenic bacteria of Staphylococcus aureus and Escherichia coli. Compared to the non-quaternized phthalocyanines 3 and 4, the cationic phthalocyanines 3a and 4a exhibit a higher photodynamic inactivation against the planktonic cells with log reduction values above 9 at a concentration of 1.25 µM. This was attributed to the positive charge which enhances cellular uptake. More interestingly, 3a and 4a show a higher photodynamic inactivation (less than 3% of S. aureus survived) on their biofilm counterparts thanks to their stronger affinity to these cells. 3a and 4a Pcs also exhibited interesting PDT activity against MCF-7 cancer cells giving IC50 values of 17.9 and 7.4 μM, respectively following 15 min irradiation. The obtained results in this work show that the positively charged phthalocyanines 3a and 4a are potential antibacterial photosensitizers that show some selectivity toward the Gram-positive and Gram-negative bacteria as well as MCF-7 breasts cancer cells.
- Full Text:
- Date Issued: 2022
- Authors: Openda, Yolande Ikala , Babu, Balaji , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300129 , vital:57895 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102863"
- Description: New tetrasubstituted zinc (II) and indium (III) phthalocyanines bearing dimethylamino chalcone group (complexes 3 and 4) as well as their quaternized analogs (3a and 4a) have been assessed for their photodynamic therapy (PDT) of cancer as well as photodynamic antimicrobial chemotherapy activities against biofilms and planktonic cultures of pathogenic bacteria of Staphylococcus aureus and Escherichia coli. Compared to the non-quaternized phthalocyanines 3 and 4, the cationic phthalocyanines 3a and 4a exhibit a higher photodynamic inactivation against the planktonic cells with log reduction values above 9 at a concentration of 1.25 µM. This was attributed to the positive charge which enhances cellular uptake. More interestingly, 3a and 4a show a higher photodynamic inactivation (less than 3% of S. aureus survived) on their biofilm counterparts thanks to their stronger affinity to these cells. 3a and 4a Pcs also exhibited interesting PDT activity against MCF-7 cancer cells giving IC50 values of 17.9 and 7.4 μM, respectively following 15 min irradiation. The obtained results in this work show that the positively charged phthalocyanines 3a and 4a are potential antibacterial photosensitizers that show some selectivity toward the Gram-positive and Gram-negative bacteria as well as MCF-7 breasts cancer cells.
- Full Text:
- Date Issued: 2022
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:
- Date Issued: 2022
- 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:
- Date Issued: 2022
The in vitro photo-sonodynamic combinatorial therapy activity of cationic and zwitterionic phthalocyanines on MCF-7 and HeLa cancer cell lines
- Nene, Lindokuhle Cindy, Buthelezi, Khanyisile, Prinsloo, Earl, Nyokong, Tebello
- Authors: Nene, Lindokuhle Cindy , Buthelezi, Khanyisile , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295891 , vital:57387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114116"
- Description: The syntheses and characterization studies of zwitterionic 2,9,16,23-tetrakis-(N-propane sultone-morpholino) zinc(II) (4) and 2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-propane sultone-morpholinomethyl))-phenoxy zinc(II) (6) phthalocyanines are reported in this work. The photophysical properties, reactive oxygen species (ROS) generation and in vitro anticancer photodynamic (PDT), sonodynamic (SDT), and photo-sonodynamic combination (PSDT) therapy activities of the Pcs were studied and compared to their cationic counterparts: (2,9,16,23-tetrakis-(N-methyl-morpholino) Zn(II)Pc, 3), (2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-methylmorpholine)-phenoxy) Zn(II)Pc, 5). The cationic Pcs maintained higher anticancer activity for all treatment types and had higher ROS generation compared to the zwitterionic Pcs. Singlet oxygen and hydroxyl radicals were generated during ultrasound and combination irradiations of the Pcs. The zwitterionic Pcs also generated carbon radicals under ultrasound and combination irradiations. The ability of the Pcs to generate ROS is essential for PDT, SDT and PSDT, thus making these Pcs potential anticancer probes for these treatment types. Furthermore, the Pcs demonstrated the ability to bind to bovine serum albumin protein.
- Full Text:
- Date Issued: 2022
- Authors: Nene, Lindokuhle Cindy , Buthelezi, Khanyisile , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295891 , vital:57387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114116"
- Description: The syntheses and characterization studies of zwitterionic 2,9,16,23-tetrakis-(N-propane sultone-morpholino) zinc(II) (4) and 2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-propane sultone-morpholinomethyl))-phenoxy zinc(II) (6) phthalocyanines are reported in this work. The photophysical properties, reactive oxygen species (ROS) generation and in vitro anticancer photodynamic (PDT), sonodynamic (SDT), and photo-sonodynamic combination (PSDT) therapy activities of the Pcs were studied and compared to their cationic counterparts: (2,9,16,23-tetrakis-(N-methyl-morpholino) Zn(II)Pc, 3), (2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-methylmorpholine)-phenoxy) Zn(II)Pc, 5). The cationic Pcs maintained higher anticancer activity for all treatment types and had higher ROS generation compared to the zwitterionic Pcs. Singlet oxygen and hydroxyl radicals were generated during ultrasound and combination irradiations of the Pcs. The zwitterionic Pcs also generated carbon radicals under ultrasound and combination irradiations. The ability of the Pcs to generate ROS is essential for PDT, SDT and PSDT, thus making these Pcs potential anticancer probes for these treatment types. Furthermore, the Pcs demonstrated the ability to bind to bovine serum albumin protein.
- Full Text:
- Date Issued: 2022
Working in poverty: Informal employment of household gardeners in Eastern Cape towns, South Africa
- King, Andrew, Shackleton, Charlie M
- Authors: King, Andrew , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401398 , vital:69731 , xlink:href="https://doi.org/10.1080/0376835X.2021.1940867"
- Description: In South Africa there has been relatively little consideration of the informal employment offered to domestic household workers and gardeners. Here we report on the number and profile of gardeners employed by private households and the wage and satisfaction rates in 12 towns of the Eastern Cape. Over 98% of the informal gardeners were male, middle-aged and with limited formal schooling. Approximately 58% of middle and upper income households employed a gardener, at a mean daily rate of R112.20 in 2019. This equated to 13 170 gardeners earning a total wage bill of R139 million p.a. across the 12 towns, which scales up to 0.7–1 million informal gardeners nationally earning approximately R10–14 billion per year. However, daily remuneration was insufficient to cover basic needs, and slightly more than half of the gardeners would prefer a different job, indicating the survivalist nature of the sector.
- Full Text:
- Date Issued: 2022
- Authors: King, Andrew , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401398 , vital:69731 , xlink:href="https://doi.org/10.1080/0376835X.2021.1940867"
- Description: In South Africa there has been relatively little consideration of the informal employment offered to domestic household workers and gardeners. Here we report on the number and profile of gardeners employed by private households and the wage and satisfaction rates in 12 towns of the Eastern Cape. Over 98% of the informal gardeners were male, middle-aged and with limited formal schooling. Approximately 58% of middle and upper income households employed a gardener, at a mean daily rate of R112.20 in 2019. This equated to 13 170 gardeners earning a total wage bill of R139 million p.a. across the 12 towns, which scales up to 0.7–1 million informal gardeners nationally earning approximately R10–14 billion per year. However, daily remuneration was insufficient to cover basic needs, and slightly more than half of the gardeners would prefer a different job, indicating the survivalist nature of the sector.
- Full Text:
- Date Issued: 2022
Adaptation and validation of a computerized neurocognitive battery in the Xhosa of South Africa
- Cobb, Scott J, Moore, Tyler M, Stein, Dan J, Pretorius, Adele, Zingela, Zukiswa, Nagdee, Mohammed, Ngqengelele, Linda, Campbell, Megan, Sibeko, Goodman, King, Mary C, McClellan, Jon M, Port, Allison M, Jackson, Chad, Ruparel, Kosha, Susser, Ezra, Gur, Ruben C
- Authors: Cobb, Scott J , Moore, Tyler M , Stein, Dan J , Pretorius, Adele , Zingela, Zukiswa , Nagdee, Mohammed , Ngqengelele, Linda , Campbell, Megan , Sibeko, Goodman , King, Mary C , McClellan, Jon M , Port, Allison M , Jackson, Chad , Ruparel, Kosha , Susser, Ezra , Gur, Ruben C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302439 , vital:58196 , xlink:href="https://doi.org/10.1037/neu0000742"
- Description: Objective: Large-scale studies have revolutionized biomedical research, and neurocognitive tests can help elucidate the biological basis of neuropsychiatric diseases. However, studies have predominantly been conducted in Western settings. We describe the development and validation of a computerized battery (PennCNB) with the Xhosa population of South Africa. Method: Individuals with schizophrenia (n = 525) and a normative comparison group (n = 744) were balanced on age, sex, education, and region. Participants provided blood samples, were assessed psychiatrically, and were administered a PennCNB translation to isiXhosa, including measures of executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed. Feasibility was examined with test completion rates and input from administrators, and psychometric structural validity and associations with clinical and demographic characteristics were examined. Results: Tests were well tolerated by participants, as >87% had one (or fewer) test missing. Results suggested a similar factor structure to prior PennCNB studies in Western contexts, and expected age and sex effects were apparent. Furthermore, a similar profile of schizophrenia was observed, with neurocognitive deficits most pronounced for executive functions, especially attention, as well as memory, social cognition, and motor speed relative to complex cognition and sensorimotor speed. Conclusions: Results support the feasibility of implementing a culturally adapted computerized neurocognitive battery in sub-Saharan African settings and provide evidence supporting the concurrent validity of the translated instrument. Thus, the PennCNB is implementable on a large scale in non-Western contexts, shows expected factor structure, and can detect cognitive deficits associated with neuropsychiatric disorders. Obtaining valid measures of cognition by nonspecialized proctors is especially suitable in resource-limited settings, where traditional testing is prohibitive. Future work should establish normative standards, test–retest reliability, and sensitivity to treatment.
- Full Text:
- Date Issued: 2021
- Authors: Cobb, Scott J , Moore, Tyler M , Stein, Dan J , Pretorius, Adele , Zingela, Zukiswa , Nagdee, Mohammed , Ngqengelele, Linda , Campbell, Megan , Sibeko, Goodman , King, Mary C , McClellan, Jon M , Port, Allison M , Jackson, Chad , Ruparel, Kosha , Susser, Ezra , Gur, Ruben C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302439 , vital:58196 , xlink:href="https://doi.org/10.1037/neu0000742"
- Description: Objective: Large-scale studies have revolutionized biomedical research, and neurocognitive tests can help elucidate the biological basis of neuropsychiatric diseases. However, studies have predominantly been conducted in Western settings. We describe the development and validation of a computerized battery (PennCNB) with the Xhosa population of South Africa. Method: Individuals with schizophrenia (n = 525) and a normative comparison group (n = 744) were balanced on age, sex, education, and region. Participants provided blood samples, were assessed psychiatrically, and were administered a PennCNB translation to isiXhosa, including measures of executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed. Feasibility was examined with test completion rates and input from administrators, and psychometric structural validity and associations with clinical and demographic characteristics were examined. Results: Tests were well tolerated by participants, as >87% had one (or fewer) test missing. Results suggested a similar factor structure to prior PennCNB studies in Western contexts, and expected age and sex effects were apparent. Furthermore, a similar profile of schizophrenia was observed, with neurocognitive deficits most pronounced for executive functions, especially attention, as well as memory, social cognition, and motor speed relative to complex cognition and sensorimotor speed. Conclusions: Results support the feasibility of implementing a culturally adapted computerized neurocognitive battery in sub-Saharan African settings and provide evidence supporting the concurrent validity of the translated instrument. Thus, the PennCNB is implementable on a large scale in non-Western contexts, shows expected factor structure, and can detect cognitive deficits associated with neuropsychiatric disorders. Obtaining valid measures of cognition by nonspecialized proctors is especially suitable in resource-limited settings, where traditional testing is prohibitive. Future work should establish normative standards, test–retest reliability, and sensitivity to treatment.
- Full Text:
- Date Issued: 2021
Aluminum corrosion retardation properties of acetamidophenoxy phthalocyanines: Effect of central metal
- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Date Issued: 2021
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Date Issued: 2021
Asymmetrical zinc (II) phthalocyanines cobalt tungstate nanomaterial conjugates for photodegradation of methylene blue
- Mgidlana, Sithi, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184991 , vital:44314 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113421"
- Description: Herein, we present syntheses of three asymmetrical zinc(II) phthalocyanine (ZnPc) complexes and hydrothermal synthesis of cobalt tungstate nanoparticles. The ZnPc derivatives were covalently linked to cobalt tungstate nanoparticles. Photophysical and photochemical behaviour of Pcs and nanoconjugates were investigated. The nanoconjugates generated higher triplet quantum yield and singlet oxygen quantum yield than the ZnPcs alone. Furthermore, in this paper photocatalytic efficiencies of ZnPc complexes and nanoconjugates were investigated for the degradation of methylene blue and higher photocatalytic behaviour was observed for the conjugates. The kinetic model was used to study photocatalytic behaviour of all the prepared photocatalysts.
- Full Text:
- Date Issued: 2021
- Authors: Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184991 , vital:44314 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113421"
- Description: Herein, we present syntheses of three asymmetrical zinc(II) phthalocyanine (ZnPc) complexes and hydrothermal synthesis of cobalt tungstate nanoparticles. The ZnPc derivatives were covalently linked to cobalt tungstate nanoparticles. Photophysical and photochemical behaviour of Pcs and nanoconjugates were investigated. The nanoconjugates generated higher triplet quantum yield and singlet oxygen quantum yield than the ZnPcs alone. Furthermore, in this paper photocatalytic efficiencies of ZnPc complexes and nanoconjugates were investigated for the degradation of methylene blue and higher photocatalytic behaviour was observed for the conjugates. The kinetic model was used to study photocatalytic behaviour of all the prepared photocatalysts.
- Full Text:
- Date Issued: 2021
Current and future biological control efforts against Solanum mauritianum (Solanaceae) in South Africa
- Venter, Nic, Cowie, Blair W, Olckers, Terence, Byrne, Marcus J
- Authors: Venter, Nic , Cowie, Blair W , Olckers, Terence , Byrne, Marcus J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414349 , vital:71138 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a14"
- Description: Solanum mauritianum Scop. (Solanaceae), colloquially referred to as bugweed in South Africa, remains a widespread invasive tree of global significance. Although biological control (biocontrol) efforts were undertaken from 1984 -2003 in South Africa, the programme eventually only released two agents, the sap-sucking lace bug Gargaphia decoris Drake (Hemiptera: Tingidae) and flowerbud-feeding weevil Anthonomus santacruzi Hustache (Coleoptera: Curculionidae). To date, these agents have been relatively ineffective in controlling S. mauritianum, largely due to low establishment success due to climatic incompatibility in relation to the widespread distribution of S. mauritianum. This has prompted the revival of S. mauritianum biocontrol research in 2018, with the programme focused largely on sourcing additional agents from climatically suitable regions in the plant’s native range in South America. Climate matching between cooler regions of South Africa and known S. mauritianum sites in South America identified Uruguay as a promising source of new agents. Field collections in Uruguay focused mainly on Anthonomus spp. but included stem-boring and shoot-galling weevils. Low incidence in the field and difficulties in culturing candidate species temporarily precluded research into stem-boring and shoot-galling candidates, but the rearing and assessment of the flowerbud-feeding weevil Anthonomus morticinus Clark (Coleoptera: Curculionidae) is ongoing. Host-specificity testing of A. morticinus has thus far confirmed a narrow host range, suggesting it has potential as a new agent.
- Full Text:
- Date Issued: 2021
- Authors: Venter, Nic , Cowie, Blair W , Olckers, Terence , Byrne, Marcus J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414349 , vital:71138 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a14"
- Description: Solanum mauritianum Scop. (Solanaceae), colloquially referred to as bugweed in South Africa, remains a widespread invasive tree of global significance. Although biological control (biocontrol) efforts were undertaken from 1984 -2003 in South Africa, the programme eventually only released two agents, the sap-sucking lace bug Gargaphia decoris Drake (Hemiptera: Tingidae) and flowerbud-feeding weevil Anthonomus santacruzi Hustache (Coleoptera: Curculionidae). To date, these agents have been relatively ineffective in controlling S. mauritianum, largely due to low establishment success due to climatic incompatibility in relation to the widespread distribution of S. mauritianum. This has prompted the revival of S. mauritianum biocontrol research in 2018, with the programme focused largely on sourcing additional agents from climatically suitable regions in the plant’s native range in South America. Climate matching between cooler regions of South Africa and known S. mauritianum sites in South America identified Uruguay as a promising source of new agents. Field collections in Uruguay focused mainly on Anthonomus spp. but included stem-boring and shoot-galling weevils. Low incidence in the field and difficulties in culturing candidate species temporarily precluded research into stem-boring and shoot-galling candidates, but the rearing and assessment of the flowerbud-feeding weevil Anthonomus morticinus Clark (Coleoptera: Curculionidae) is ongoing. Host-specificity testing of A. morticinus has thus far confirmed a narrow host range, suggesting it has potential as a new agent.
- Full Text:
- Date Issued: 2021
Photocatalytic and solar radiation harvesting potential of a free-base porphyrin-zinc (II) phthalocyanine heterodyad functionalized polystyrene polymer membrane for the degradation of 4-chlorophenol
- Mafukidze, Donovan M, Nyokong, Tebello
- Authors: Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185772 , vital:44422 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113142"
- Description: In this work a novel porphyrin-phthalocyanine heterodyad (complex 4) was synthesized and embedded in polystyrene polymer membranes. The singlet oxygen generation of 4 improved in comparison to the parent porphyrin and phthalocyanine complexes giving singlet oxygen quantum yields of 0.67 and 0.51 (in dimethyl sulfoxide) where the porphyrin and phthalocyanine complementarily absorb respectively. Successful Buchwald-Hartwig coupling of complex 4 to amine functionalized polystyrene ((NH2)PS) gave a complex loading of 24.6 mg complex/g 4-PS. Embedding of 4-PS in polystyrene polymer membrane yielded the photoactive 4-memb which proved to be capable of degrading 4-chlorophenol at reaction rates of at least 1.12 × 10−7 molL-1 min-1 and half-life of 193 min in a pseudo first order reaction at an initial concentration of 3.10 × 10-5. Also, light harvesting experiments proved 4-memb to be active in the whole 300–700 nm wavelength range with the greatest activity being under white light.
- Full Text:
- Date Issued: 2021
- Authors: Mafukidze, Donovan M , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185772 , vital:44422 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113142"
- Description: In this work a novel porphyrin-phthalocyanine heterodyad (complex 4) was synthesized and embedded in polystyrene polymer membranes. The singlet oxygen generation of 4 improved in comparison to the parent porphyrin and phthalocyanine complexes giving singlet oxygen quantum yields of 0.67 and 0.51 (in dimethyl sulfoxide) where the porphyrin and phthalocyanine complementarily absorb respectively. Successful Buchwald-Hartwig coupling of complex 4 to amine functionalized polystyrene ((NH2)PS) gave a complex loading of 24.6 mg complex/g 4-PS. Embedding of 4-PS in polystyrene polymer membrane yielded the photoactive 4-memb which proved to be capable of degrading 4-chlorophenol at reaction rates of at least 1.12 × 10−7 molL-1 min-1 and half-life of 193 min in a pseudo first order reaction at an initial concentration of 3.10 × 10-5. Also, light harvesting experiments proved 4-memb to be active in the whole 300–700 nm wavelength range with the greatest activity being under white light.
- Full Text:
- Date Issued: 2021
SANCDB: an update on South African natural compounds and their readily available analogs
- Diallo, Bakary N, Glenister, Michael, Musyoka, Thommas M, Lobb, Kevin A, Taştan Bishop, Özlem
- Authors: Diallo, Bakary N , Glenister, Michael , Musyoka, Thommas M , Lobb, Kevin A , Taştan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451154 , vital:75023 , xlink:href="https://doi.org/10.1186/s13321-021-00514-2"
- Description: The dimeric dihydropyrimidine dehydrogenase (DPD), metalloenzyme, an adjunct anti-cancer drug target, contains highly specialized 4 × Fe2+4S2−4 clusters per chain. These clusters facilitate the catalysis of the rate-limiting step in the pyrimidine degradation pathway through a harmonized electron transfer cascade that triggers a redox catabolic reaction. In the process, the bulk of the administered 5-fluorouracil (5-FU) cancer drug is inactivated, while a small proportion is activated to nucleic acid antimetabolites. The occurrence of missense mutations in DPD protein within the general population, including those of African descent, has adverse toxicity effects due to altered 5-FU metabolism. Thus, deciphering mutation effects on protein structure and function is vital, especially for precision medicine purposes. We previously proposed combining molecular dynamics (MD) and dynamic residue network (DRN) analysis to decipher the molecular mechanisms of missense mutations in other proteins. However, the presence of Fe2+4S2−4 clusters in DPD poses a challenge for such in silico studies. The existing AMBER force field parameters cannot accurately describe the Fe2+ center coordination exhibited by this enzyme. Therefore, this study aimed to derive AMBER force field parameters for DPD enzyme Fe2+ centers, using the original Seminario method and the collation features Visual Force Field Derivation Toolkit as a supportive approach. All-atom MD simulations were performed to validate the results. Both approaches generated similar force field parameters, which accurately described the human DPD protein Fe2+4S2−4 cluster architecture. This information is crucial and opens new avenues for in silico cancer pharmacogenomics and drug discovery related research on 5-FU drug efficacy and toxicity issues.
- Full Text:
- Date Issued: 2021
- Authors: Diallo, Bakary N , Glenister, Michael , Musyoka, Thommas M , Lobb, Kevin A , Taştan Bishop, Özlem
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451154 , vital:75023 , xlink:href="https://doi.org/10.1186/s13321-021-00514-2"
- Description: The dimeric dihydropyrimidine dehydrogenase (DPD), metalloenzyme, an adjunct anti-cancer drug target, contains highly specialized 4 × Fe2+4S2−4 clusters per chain. These clusters facilitate the catalysis of the rate-limiting step in the pyrimidine degradation pathway through a harmonized electron transfer cascade that triggers a redox catabolic reaction. In the process, the bulk of the administered 5-fluorouracil (5-FU) cancer drug is inactivated, while a small proportion is activated to nucleic acid antimetabolites. The occurrence of missense mutations in DPD protein within the general population, including those of African descent, has adverse toxicity effects due to altered 5-FU metabolism. Thus, deciphering mutation effects on protein structure and function is vital, especially for precision medicine purposes. We previously proposed combining molecular dynamics (MD) and dynamic residue network (DRN) analysis to decipher the molecular mechanisms of missense mutations in other proteins. However, the presence of Fe2+4S2−4 clusters in DPD poses a challenge for such in silico studies. The existing AMBER force field parameters cannot accurately describe the Fe2+ center coordination exhibited by this enzyme. Therefore, this study aimed to derive AMBER force field parameters for DPD enzyme Fe2+ centers, using the original Seminario method and the collation features Visual Force Field Derivation Toolkit as a supportive approach. All-atom MD simulations were performed to validate the results. Both approaches generated similar force field parameters, which accurately described the human DPD protein Fe2+4S2−4 cluster architecture. This information is crucial and opens new avenues for in silico cancer pharmacogenomics and drug discovery related research on 5-FU drug efficacy and toxicity issues.
- 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