Borneol-triarylcorrole hybrids with chiral-optical response and anticancer behaviours
- Fu, Bo, Wang, Lin, Yu, Xiaoxiao, Fang, Xianying, Mack, John, Dingiswayo, Somila, Nyokong, Tebello, Liang, Xu, Xu, Haijun
- Authors: Fu, Bo , Wang, Lin , Yu, Xiaoxiao , Fang, Xianying , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu , Xu, Haijun
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185294 , vital:44362 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109699"
- Description: A series of four multifunctional A2B type H3corroles with meso-borneol substituents at the B position have been synthesized and characterized. A detailed analysis of the optical properties was carried out, and a comparison was made with theoretical calculations to identify the key trends in the structure-property relationships. The meso-borneol substituent couples with the corrole core leading to clear CD signals in the B band region. Enhanced anti-cancer properties are observed in vitro relative to (−)-borneol with cell inhibition rates of up to 94%.
- Full Text:
- Date Issued: 2021
- Authors: Fu, Bo , Wang, Lin , Yu, Xiaoxiao , Fang, Xianying , Mack, John , Dingiswayo, Somila , Nyokong, Tebello , Liang, Xu , Xu, Haijun
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185294 , vital:44362 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109699"
- Description: A series of four multifunctional A2B type H3corroles with meso-borneol substituents at the B position have been synthesized and characterized. A detailed analysis of the optical properties was carried out, and a comparison was made with theoretical calculations to identify the key trends in the structure-property relationships. The meso-borneol substituent couples with the corrole core leading to clear CD signals in the B band region. Enhanced anti-cancer properties are observed in vitro relative to (−)-borneol with cell inhibition rates of up to 94%.
- Full Text:
- Date Issued: 2021
Bridging through “women’s work"
- Authors: Magadla, Siphokazi
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298650 , vital:57724 , xlink:href="https://doi.org/10.1080/14616742.2020.1863158"
- Description: Bodomo’s bridge theory describes and predicts the long-term implications of African migrants’ activities and settlement in China. Drawing on research with African retail traders, university students, and corporate executives in China, I show that the bridge theory illuminates how African women and men rationalize their decisions to migrate to China within the context of the rise of Asia. Drawing on the literature regarding African women and work, I explain that structural economic conditions now force more Africans into economic sectors such as trade work that historically were dominated by African women. I demonstrate that African women’s roles as economic providers for their families and children in other sectors, such as university students and company executives, provide evidence of the continued “matricentric” nature of African households that rely on women’s economic productivity. I also examine the possibilities and limitations of building long-standing networks that shape African migrant settlement in China. I show that the historical theorization that characterizes global mobility as male – particularly regarding Africans – has contributed to the misrecognition of African women’s multiple activities in China.
- Full Text:
- Date Issued: 2021
- Authors: Magadla, Siphokazi
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298650 , vital:57724 , xlink:href="https://doi.org/10.1080/14616742.2020.1863158"
- Description: Bodomo’s bridge theory describes and predicts the long-term implications of African migrants’ activities and settlement in China. Drawing on research with African retail traders, university students, and corporate executives in China, I show that the bridge theory illuminates how African women and men rationalize their decisions to migrate to China within the context of the rise of Asia. Drawing on the literature regarding African women and work, I explain that structural economic conditions now force more Africans into economic sectors such as trade work that historically were dominated by African women. I demonstrate that African women’s roles as economic providers for their families and children in other sectors, such as university students and company executives, provide evidence of the continued “matricentric” nature of African households that rely on women’s economic productivity. I also examine the possibilities and limitations of building long-standing networks that shape African migrant settlement in China. I show that the historical theorization that characterizes global mobility as male – particularly regarding Africans – has contributed to the misrecognition of African women’s multiple activities in China.
- Full Text:
- Date Issued: 2021
Cereal stem borer (Lepidoptera) assemblage structure in a sub-tropical agro-ecosystem, Eastern Cape Province, South Africa
- Authors: Niba, AS. , Mdazu, S.
- Date: 2021
- Subjects: Cereal products Stem borers Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6958 , vital:52619 , xlink:href="https://doi.org/10.1080/0035919X.2021.1893861"
- Description: Insect pests, especially lepidopterous stem borers, cause significant losses to cereal production at local and global scales. The borer species associated with cultivated grain cereals and alternative wild host plants were identified at three elevation gradients in the former Transkei area of the Eastern Cape Province, South Africa. Stem borer sampling was undertaken during maize crop and non-crop seasons in Port St Johns (PSJ), Mthatha and Elliot, sites that differ in elevation above sea level, annual precipitation and temperature. Morphologically identical borers retrieved from each sampling unit were recorded, processed and reared to adult stage for identification at an ambient temperature range of 25–28°C and a relative humidity range of 65–80%. Specimens were sorted first into morphospecies (MS1–MS6) based on external morphological characteristics. Six stem borer species (Busseola fusca, Sesamia calamistis, Eldana saccharina, Chilo orichalcocili, Chilo sacchariphagus and Chilo partellus) were collected during the survey. E. saccharina and C. orichalcocili were absent in PSJ; in Elliot, E. saccahrina occurred in very low numbers whereas C. partellus was absent. Busseola fusca was more abundant at high altitude (i.e. Elliot). Borer community structure in the study showed similarity between Mthatha and Elliot. Species richness and abundance across study sites were not statistically significant (P > 0.05). The study provides information on borer species occurrence in the study area, and techniques to identify larval stages for effective control by local farmers and extension workers. When designing strategies for borer control, elevation may not be a major concern at this spatial scale.
- Full Text:
- Date Issued: 2021
- Authors: Niba, AS. , Mdazu, S.
- Date: 2021
- Subjects: Cereal products Stem borers Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6958 , vital:52619 , xlink:href="https://doi.org/10.1080/0035919X.2021.1893861"
- Description: Insect pests, especially lepidopterous stem borers, cause significant losses to cereal production at local and global scales. The borer species associated with cultivated grain cereals and alternative wild host plants were identified at three elevation gradients in the former Transkei area of the Eastern Cape Province, South Africa. Stem borer sampling was undertaken during maize crop and non-crop seasons in Port St Johns (PSJ), Mthatha and Elliot, sites that differ in elevation above sea level, annual precipitation and temperature. Morphologically identical borers retrieved from each sampling unit were recorded, processed and reared to adult stage for identification at an ambient temperature range of 25–28°C and a relative humidity range of 65–80%. Specimens were sorted first into morphospecies (MS1–MS6) based on external morphological characteristics. Six stem borer species (Busseola fusca, Sesamia calamistis, Eldana saccharina, Chilo orichalcocili, Chilo sacchariphagus and Chilo partellus) were collected during the survey. E. saccharina and C. orichalcocili were absent in PSJ; in Elliot, E. saccahrina occurred in very low numbers whereas C. partellus was absent. Busseola fusca was more abundant at high altitude (i.e. Elliot). Borer community structure in the study showed similarity between Mthatha and Elliot. Species richness and abundance across study sites were not statistically significant (P > 0.05). The study provides information on borer species occurrence in the study area, and techniques to identify larval stages for effective control by local farmers and extension workers. When designing strategies for borer control, elevation may not be a major concern at this spatial scale.
- Full Text:
- Date Issued: 2021
Cereal stem borer (Lepidoptera) assemblage structure in a sub-tropical agro-ecosystem, Eastern Cape Province, South Africa
- Authors: Niba, AS. , Mdazu, S.
- Date: 2021
- Subjects: Cereal products Stem borers Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6948 , vital:52620 , xlink:href="https://doi.org/10.1080/0035919X.2021.1893861"
- Description: Insect pests, especially lepidopterous stem borers, cause significant losses to cereal production at local and global scales. The borer species associated with cultivated grain cereals and alternative wild host plants were identified at three elevation gradients in the former Transkei area of the Eastern Cape Province, South Africa. Stem borer sampling was undertaken during maize crop and non-crop seasons in Port St Johns (PSJ), Mthatha and Elliot, sites that differ in elevation above sea level, annual precipitation and temperature. Morphologically identical borers retrieved from each sampling unit were recorded, processed and reared to adult stage for identification at an ambient temperature range of 25–28°C and a relative humidity range of 65–80%. Specimens were sorted first into morphospecies (MS1–MS6) based on external morphological characteristics. Six stem borer species (Busseola fusca, Sesamia calamistis, Eldana saccharina, Chilo orichalcocili, Chilo sacchariphagus and Chilo partellus) were collected during the survey. E. saccharina and C. orichalcocili were absent in PSJ; in Elliot, E. saccahrina occurred in very low numbers whereas C. partellus was absent. Busseola fusca was more abundant at high altitude (i.e. Elliot). Borer community structure in the study showed similarity between Mthatha and Elliot. Species richness and abundance across study sites were not statistically significant (P > 0.05). The study provides information on borer species occurrence in the study area, and techniques to identify larval stages for effective control by local farmers and extension workers. When designing strategies for borer control, elevation may not be a major concern at this spatial scale.
- Full Text:
- Date Issued: 2021
- Authors: Niba, AS. , Mdazu, S.
- Date: 2021
- Subjects: Cereal products Stem borers Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6948 , vital:52620 , xlink:href="https://doi.org/10.1080/0035919X.2021.1893861"
- Description: Insect pests, especially lepidopterous stem borers, cause significant losses to cereal production at local and global scales. The borer species associated with cultivated grain cereals and alternative wild host plants were identified at three elevation gradients in the former Transkei area of the Eastern Cape Province, South Africa. Stem borer sampling was undertaken during maize crop and non-crop seasons in Port St Johns (PSJ), Mthatha and Elliot, sites that differ in elevation above sea level, annual precipitation and temperature. Morphologically identical borers retrieved from each sampling unit were recorded, processed and reared to adult stage for identification at an ambient temperature range of 25–28°C and a relative humidity range of 65–80%. Specimens were sorted first into morphospecies (MS1–MS6) based on external morphological characteristics. Six stem borer species (Busseola fusca, Sesamia calamistis, Eldana saccharina, Chilo orichalcocili, Chilo sacchariphagus and Chilo partellus) were collected during the survey. E. saccharina and C. orichalcocili were absent in PSJ; in Elliot, E. saccahrina occurred in very low numbers whereas C. partellus was absent. Busseola fusca was more abundant at high altitude (i.e. Elliot). Borer community structure in the study showed similarity between Mthatha and Elliot. Species richness and abundance across study sites were not statistically significant (P > 0.05). The study provides information on borer species occurrence in the study area, and techniques to identify larval stages for effective control by local farmers and extension workers. When designing strategies for borer control, elevation may not be a major concern at this spatial scale.
- Full Text:
- Date Issued: 2021
Clinical outcomes of hospitalised COVID-19 patients at Mthatha Regional Hospital, Eastern Cape, South Africa: A retrospective study
- Kaswa, Ramprakash, Yogeswaran, Parimalaranie, Cawe, Busisiwe
- Authors: Kaswa, Ramprakash , Yogeswaran, Parimalaranie , Cawe, Busisiwe
- Date: 2021
- Subjects: COVID-19 Diabetes Hypertension Diseases Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7330 , vital:53402 , xlink:href="https://doi.org/10.4102/safp.v63i1.5253"
- Description: Background: Coronavirus disease 2019 (COVID-19) is a public health crisis that threatens the current health system. The sudden expansion in the need for inpatient and intensive care facilities raised concerns about optimal clinical management and resource allocation. Despite the pressing need for evidence to make context-specific decisions on COVID-19 management, evidence from South Africa remained limited. This study aimed to describe the clinical characteristics and outcomes of COVID-19 hospitalised patients. Methods: A retrospective cross-sectional study design was used to evaluate the clinical outcomes of hospitalised adult patients (≥ 18 years old) with laboratory-confirmed COVID-19 illness at Mthatha Regional Hospital (MRH), Eastern Cape. Results: Of the 1814 patients tested for COVID-19 between 20 March 2020 and 31 July 2020 at MRH, two-thirds (65.4%) were female. About two-thirds (242) of the 392 patients (21.6%) who tested positive for this disease were hospitalised and one-third (150) were quarantined at home. The mean age of the patients tested for COVID-19 was 42.6 years and there was no difference between males and females. The mean age of hospitalised patients was 55.5 years and the mean age of hospitalised patients who died (61.3 years) was much higher than recovered (49.5 years). Overall, 188 (77.6%) hospitalised patients had clinical comorbidity on admission. Diabetes (36.8%) and hypertension (33.1%) were the most common comorbidities amongst COVID-19 hospitalised patients. Conclusion: The majority of the patients who were hospitalised for COVID-19 were elderly and had high baseline comorbidities. Advance age and underlying comorbidities (diabetes, hypertension and HIV) were associated with high mortality in hospitalised COVID-19 patients. Keywords: COVID-19, diabetes; hypertension; hospitalised; co-morbidity.
- Full Text:
- Date Issued: 2021
- Authors: Kaswa, Ramprakash , Yogeswaran, Parimalaranie , Cawe, Busisiwe
- Date: 2021
- Subjects: COVID-19 Diabetes Hypertension Diseases Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7330 , vital:53402 , xlink:href="https://doi.org/10.4102/safp.v63i1.5253"
- Description: Background: Coronavirus disease 2019 (COVID-19) is a public health crisis that threatens the current health system. The sudden expansion in the need for inpatient and intensive care facilities raised concerns about optimal clinical management and resource allocation. Despite the pressing need for evidence to make context-specific decisions on COVID-19 management, evidence from South Africa remained limited. This study aimed to describe the clinical characteristics and outcomes of COVID-19 hospitalised patients. Methods: A retrospective cross-sectional study design was used to evaluate the clinical outcomes of hospitalised adult patients (≥ 18 years old) with laboratory-confirmed COVID-19 illness at Mthatha Regional Hospital (MRH), Eastern Cape. Results: Of the 1814 patients tested for COVID-19 between 20 March 2020 and 31 July 2020 at MRH, two-thirds (65.4%) were female. About two-thirds (242) of the 392 patients (21.6%) who tested positive for this disease were hospitalised and one-third (150) were quarantined at home. The mean age of the patients tested for COVID-19 was 42.6 years and there was no difference between males and females. The mean age of hospitalised patients was 55.5 years and the mean age of hospitalised patients who died (61.3 years) was much higher than recovered (49.5 years). Overall, 188 (77.6%) hospitalised patients had clinical comorbidity on admission. Diabetes (36.8%) and hypertension (33.1%) were the most common comorbidities amongst COVID-19 hospitalised patients. Conclusion: The majority of the patients who were hospitalised for COVID-19 were elderly and had high baseline comorbidities. Advance age and underlying comorbidities (diabetes, hypertension and HIV) were associated with high mortality in hospitalised COVID-19 patients. Keywords: COVID-19, diabetes; hypertension; hospitalised; co-morbidity.
- Full Text:
- Date Issued: 2021
Constraints on improving higher education teaching and learning through funding
- Authors: Moyo, Temwa , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185854 , vital:44440 , xlink:href="http://dx.doi.org/10.17159/sajs.2021/7807"
- Description: In the midst of massification, targeted funding has been used in various countries to address inefficiencies in teaching and learning. In South Africa, arguments have been made for significant investments to be made and the University Capacity Development Grant (UCDG) in particular is being used as a driver for improved outputs. Prior to its implementation in 2018, the UCDG comprised the Research Development Grant and the Teaching Development Grant. The Teaching Development Grant was intended to address low retention and throughput rates and ZAR5.5 billion was spent to this end over a 12-year period. The analysis presented here of all Teaching Development Grant budget plans and progress reports from 2007 to 2015 shows that the undifferentiated implementation of the Teaching Development Grant within a differentiated sector limited its potential for system-wide gains. Institutions without adequate resources tended to divert Teaching Development Grant funds to attend to backlogs rather than to address teaching and learning practices and such universities lost much of their allocation through the withholding of unspent funds. This blanket practice addressed the symptoms of underspending but not the structural, cultural and agential mechanisms that led to such under-expenditure. Uneven access to the limited teaching development expertise also impacted on the use of the grant. This call for a context-based approach to funding has been identified as a key success factor in grant interventions in both African and European universities. We recommend a sector-wide response in the form of a national body or plan for the benefit of all universities and investment in financial management enhancement. The study contributes to a better understanding of how government funding interventions can achieve intended goals. The study calls for a more contextualised approach to funding and to greater collaboration across the sector to maximise limited capacity.
- Full Text:
- Date Issued: 2021
- Authors: Moyo, Temwa , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185854 , vital:44440 , xlink:href="http://dx.doi.org/10.17159/sajs.2021/7807"
- Description: In the midst of massification, targeted funding has been used in various countries to address inefficiencies in teaching and learning. In South Africa, arguments have been made for significant investments to be made and the University Capacity Development Grant (UCDG) in particular is being used as a driver for improved outputs. Prior to its implementation in 2018, the UCDG comprised the Research Development Grant and the Teaching Development Grant. The Teaching Development Grant was intended to address low retention and throughput rates and ZAR5.5 billion was spent to this end over a 12-year period. The analysis presented here of all Teaching Development Grant budget plans and progress reports from 2007 to 2015 shows that the undifferentiated implementation of the Teaching Development Grant within a differentiated sector limited its potential for system-wide gains. Institutions without adequate resources tended to divert Teaching Development Grant funds to attend to backlogs rather than to address teaching and learning practices and such universities lost much of their allocation through the withholding of unspent funds. This blanket practice addressed the symptoms of underspending but not the structural, cultural and agential mechanisms that led to such under-expenditure. Uneven access to the limited teaching development expertise also impacted on the use of the grant. This call for a context-based approach to funding has been identified as a key success factor in grant interventions in both African and European universities. We recommend a sector-wide response in the form of a national body or plan for the benefit of all universities and investment in financial management enhancement. The study contributes to a better understanding of how government funding interventions can achieve intended goals. The study calls for a more contextualised approach to funding and to greater collaboration across the sector to maximise limited capacity.
- Full Text:
- Date Issued: 2021
Covid-19 and the restrictive measures: The national security conundrum for Zimbabwe
- Mugari, Ishmael, Obioha, Emeka E.
- Authors: Mugari, Ishmael , Obioha, Emeka E.
- Date: 2021
- Subjects: COVID-19 (Disease) National security Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6926 , vital:52571 , xlink:href="https://10.1080/10246029.2021.1972015"
- Description: The emergence of the COVID-19 pandemic at the onset of the year 2020 brought unprecedented suffering to humanity. Economic activities in virtually all nations across the globe were brought to a shuddering halt, with the third world suffering the worst effects on the economic front. The health security of nations across the globe was shaken, as nations came to terms with the surging health needs for the infected citizens. In order to grapple with the pandemic, nations took drastic measures, chief among them being the implementation of lockdowns, coupled with harsh restrictions. These measures, however, came at a cost. This paper explores the impacts of the restrictive measures that were implemented by the Zimbabwean government to combat COVID-19 pandemic. The paper interrogates these measures in the context of the national security discourse. In the analysis, the paper also makes reference to South Africa- a more developed nation and Zimbabwe’s neighbour. Keywords: COVID-19 , national security, health security, lockdown
- Full Text:
- Date Issued: 2021
- Authors: Mugari, Ishmael , Obioha, Emeka E.
- Date: 2021
- Subjects: COVID-19 (Disease) National security Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6926 , vital:52571 , xlink:href="https://10.1080/10246029.2021.1972015"
- Description: The emergence of the COVID-19 pandemic at the onset of the year 2020 brought unprecedented suffering to humanity. Economic activities in virtually all nations across the globe were brought to a shuddering halt, with the third world suffering the worst effects on the economic front. The health security of nations across the globe was shaken, as nations came to terms with the surging health needs for the infected citizens. In order to grapple with the pandemic, nations took drastic measures, chief among them being the implementation of lockdowns, coupled with harsh restrictions. These measures, however, came at a cost. This paper explores the impacts of the restrictive measures that were implemented by the Zimbabwean government to combat COVID-19 pandemic. The paper interrogates these measures in the context of the national security discourse. In the analysis, the paper also makes reference to South Africa- a more developed nation and Zimbabwe’s neighbour. Keywords: COVID-19 , national security, health security, lockdown
- Full Text:
- Date Issued: 2021
Creating the Ideal Push-Pull System for Electrocatalysis A Comparative Study on Symmetrical and Asymmetrical Cardanol-based Cobalt Phthalocyanines
- Nkhahle, Reitumetse, Nyokong, Tebello
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:44452 , xlink:href="https://doi.org/10.1002/elan.202060019"
- Description: A symmetrical cardanol-based cobalt phthalocyanine (Pc) along with its asymmetrical acid-based derivatives were synthesized and applied in the electrocatalysis of hydrazine. Despite the inhibition of electron movement by the bulky cardanol-based substituent throughout the series of molecules, an ideal combination of substituents was established in GCE-3 (2,9,16-tris(3- pentadecylphenoxy)-23-mono propionic acid phthalocyanato cobalt (II)) where a limit of detection (LoD) value of 5.10 μM (signal to noise ratio=5) was recorded for the detection of hydrazine. The results obtained serve as an illustration that the combination of electron-donating and electron-withdrawing substituents has a significant influence on the complete functioning of the phthalocyanine molecule(s) being investigated.
- Full Text:
- Date Issued: 2021
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:44452 , xlink:href="https://doi.org/10.1002/elan.202060019"
- Description: A symmetrical cardanol-based cobalt phthalocyanine (Pc) along with its asymmetrical acid-based derivatives were synthesized and applied in the electrocatalysis of hydrazine. Despite the inhibition of electron movement by the bulky cardanol-based substituent throughout the series of molecules, an ideal combination of substituents was established in GCE-3 (2,9,16-tris(3- pentadecylphenoxy)-23-mono propionic acid phthalocyanato cobalt (II)) where a limit of detection (LoD) value of 5.10 μM (signal to noise ratio=5) was recorded for the detection of hydrazine. The results obtained serve as an illustration that the combination of electron-donating and electron-withdrawing substituents has a significant influence on the complete functioning of the phthalocyanine molecule(s) being investigated.
- Full Text:
- Date Issued: 2021
Crossing the border from candidate to supervisor: The need for appropriate development
- Motshoane, Puleng, McKenna, Sioux
- Authors: Motshoane, Puleng , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185876 , vital:44442 , xlink:href="https://doi.org/10.1080/13562517.2021.1900814"
- Description: Postgraduate education has grown enormously worldwide, which has led to supervisors being expected to take on a supervisor's role immediately upon graduation. But crossing the border from being a doctoral candidate to becoming a doctoral supervisor entails significant shifts in identity and an understanding of postgraduate pedagogy and institutional expectations. This paper argues that supervision development opportunities are crucial, but they need to be contextualised and include critical key agents with some institutional authority if they are to be deemed worthwhile and effect change. An online survey completed by 186 participants from across institutional types and disciplines in South Africa is analysed using Archer's social realism to provide insights into how emerging supervisors are currently supported. The resultant recommendations on supervision development could contribute to more confident border crossing by emerging supervisors.
- Full Text:
- Date Issued: 2021
- Authors: Motshoane, Puleng , McKenna, Sioux
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185876 , vital:44442 , xlink:href="https://doi.org/10.1080/13562517.2021.1900814"
- Description: Postgraduate education has grown enormously worldwide, which has led to supervisors being expected to take on a supervisor's role immediately upon graduation. But crossing the border from being a doctoral candidate to becoming a doctoral supervisor entails significant shifts in identity and an understanding of postgraduate pedagogy and institutional expectations. This paper argues that supervision development opportunities are crucial, but they need to be contextualised and include critical key agents with some institutional authority if they are to be deemed worthwhile and effect change. An online survey completed by 186 participants from across institutional types and disciplines in South Africa is analysed using Archer's social realism to provide insights into how emerging supervisors are currently supported. The resultant recommendations on supervision development could contribute to more confident border crossing by emerging supervisors.
- 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, Byrnes, Marcus J
- Authors: Venter, Nic , Cowie, Blair W , Olckers, Terence , Byrnes, 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 , Byrnes, 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
Developments and prospects for biological control of Prosopis (Leguminosae) in South Africa
- Kleinjan,Catharina, Hoffman, John H, Heystek, F, Ivey, Philip J, Kistensamy, Y
- Authors: Kleinjan,Catharina , Hoffman, John H , Heystek, F , Ivey, Philip J , Kistensamy, Y
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414360 , vital:71139 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a13"
- Description: South Africa was the first country to deploy biological control (biocontrol) against invasive Prosopis populations. Developments in this regard have been ongoing, and have been reviewed, at approximately 10-year intervals, since 1991. This review spans the period 2011-2020, a timespan globally characterised by increased awareness of the impacts of invasive Prosopis populations, and recognition of the need for improved management. Concerted international collaboration has resulted in enhanced clarity on phylogenetic relationships within the Leguminosae and the phylogenetic placement of Prosopis. These advances have improved the framework for interpreting the host range of potential agents and for evaluating risk. At the outset of the biocontrol programme, in the 1980s, only agents that consumed mature seeds were considered. The intention was to reduce the invasiveness of Prosopis while simultaneously retaining it as a usable resource. The programme was subsequently expanded to investigate agents that prevent pod set or maturation of seed. More recently, potential agents that damage the vegetative growth of the plants have been included in response to recognition in South Africa, that there is no other route to successful management of Prosopis. There is a wealth of largely unexplored potential in this regard.
- Full Text:
- Date Issued: 2021
- Authors: Kleinjan,Catharina , Hoffman, John H , Heystek, F , Ivey, Philip J , Kistensamy, Y
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414360 , vital:71139 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a13"
- Description: South Africa was the first country to deploy biological control (biocontrol) against invasive Prosopis populations. Developments in this regard have been ongoing, and have been reviewed, at approximately 10-year intervals, since 1991. This review spans the period 2011-2020, a timespan globally characterised by increased awareness of the impacts of invasive Prosopis populations, and recognition of the need for improved management. Concerted international collaboration has resulted in enhanced clarity on phylogenetic relationships within the Leguminosae and the phylogenetic placement of Prosopis. These advances have improved the framework for interpreting the host range of potential agents and for evaluating risk. At the outset of the biocontrol programme, in the 1980s, only agents that consumed mature seeds were considered. The intention was to reduce the invasiveness of Prosopis while simultaneously retaining it as a usable resource. The programme was subsequently expanded to investigate agents that prevent pod set or maturation of seed. More recently, potential agents that damage the vegetative growth of the plants have been included in response to recognition in South Africa, that there is no other route to successful management of Prosopis. There is a wealth of largely unexplored potential in this regard.
- Full Text:
- Date Issued: 2021
Disilane-bridged architectures with high optical transparency for optical limiting
- Feng, Hongjie, Zhou, Zhikuan, May, Aviwe K, Chen, Jiaying, Mack, John, Nyokong, Tebello, Gai, Lizhi, Lu, Hua
- Authors: Feng, Hongjie , Zhou, Zhikuan , May, Aviwe K , Chen, Jiaying , Mack, John , Nyokong, Tebello , Gai, Lizhi , Lu, Hua
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190623 , vital:45011 , xlink:href="https://doi.org/10.1039/D1TC01488A"
- Description: A novel tetraphenylethylene (TPE) architecture that makes use of a disilane bridge was developed to successfully prepare organic optical power limiting (OPL) materials with high transparency. The σ-bridged TPE derivatives exhibit enhanced solid-state emission efficacies up to 4 times that of TPE. Due to the unique σ-electron delocalization, the incorporated Si–Si bridge gives rise to intense nonlinear optics (NLO) properties. These compounds show favorable optical transparency in the visible region, since the σ–π interaction has a relatively minor effect on the absorption properties of TPE. The poly(bisphenol A carbonate) (PBC) thin films of disilane-bridged compounds exhibit significant reverse saturable absorbance (RSA) responses during Z-scan measurements at 532 nm. In contrast, negligible OPL properties were observed in tetrahydrofuran (THF) solution and when a PBC thin film was prepared with TPE. The disilane-bridged molecular system represents a novel and easily prepared architecture for the construction of solid-state optical limiting materials.
- Full Text:
- Date Issued: 2021
- Authors: Feng, Hongjie , Zhou, Zhikuan , May, Aviwe K , Chen, Jiaying , Mack, John , Nyokong, Tebello , Gai, Lizhi , Lu, Hua
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190623 , vital:45011 , xlink:href="https://doi.org/10.1039/D1TC01488A"
- Description: A novel tetraphenylethylene (TPE) architecture that makes use of a disilane bridge was developed to successfully prepare organic optical power limiting (OPL) materials with high transparency. The σ-bridged TPE derivatives exhibit enhanced solid-state emission efficacies up to 4 times that of TPE. Due to the unique σ-electron delocalization, the incorporated Si–Si bridge gives rise to intense nonlinear optics (NLO) properties. These compounds show favorable optical transparency in the visible region, since the σ–π interaction has a relatively minor effect on the absorption properties of TPE. The poly(bisphenol A carbonate) (PBC) thin films of disilane-bridged compounds exhibit significant reverse saturable absorbance (RSA) responses during Z-scan measurements at 532 nm. In contrast, negligible OPL properties were observed in tetrahydrofuran (THF) solution and when a PBC thin film was prepared with TPE. The disilane-bridged molecular system represents a novel and easily prepared architecture for the construction of solid-state optical limiting materials.
- Full Text:
- Date Issued: 2021
Diversity is an asset to science not a threat
- Authors: Blackie, Margaret A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426624 , vital:72373 , xlink:href="https://www.jstor.org/stable/48687065"
- Description: In this paper, Critical Realism is used as a theoretical framework to show that diversity is an asset to science not a threat. Critical Realism situates the reliability and reproducibility of science in the realm of the real and thus relocates the notion of “objectivity” from the person of the scientist to the process of science. This means that it no longer necessary to attempt to minimise the person of the scientist in pursuit of rigorous knowledge. The implication is that diversity both in terms of intellectual training (within limits) and in terms of being multicultural, gender, sexuality, multilingual, is revealed to be an asset. This is because the construction of knowledge draws on personal experience and having people with divergent experience interrogating the same problem is more likely to provide a reliable, reproducible solution. In the latter parts of the paper, the implications for teaching are described. In addition, it is demonstrated that this argument can be extended into different knowledge areas.
- Full Text:
- Date Issued: 2021
- Authors: Blackie, Margaret A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426624 , vital:72373 , xlink:href="https://www.jstor.org/stable/48687065"
- Description: In this paper, Critical Realism is used as a theoretical framework to show that diversity is an asset to science not a threat. Critical Realism situates the reliability and reproducibility of science in the realm of the real and thus relocates the notion of “objectivity” from the person of the scientist to the process of science. This means that it no longer necessary to attempt to minimise the person of the scientist in pursuit of rigorous knowledge. The implication is that diversity both in terms of intellectual training (within limits) and in terms of being multicultural, gender, sexuality, multilingual, is revealed to be an asset. This is because the construction of knowledge draws on personal experience and having people with divergent experience interrogating the same problem is more likely to provide a reliable, reproducible solution. In the latter parts of the paper, the implications for teaching are described. In addition, it is demonstrated that this argument can be extended into different knowledge areas.
- Full Text:
- Date Issued: 2021
Doctors’ practice and attitudes towards red blood cell transfusion at Mthatha Regional Hospital, Eastern Cape, South Africa: A mixed methods study
- O’Mahony, Don, Adedayo, Temitope, Adeleke, Olukayode
- Authors: O’Mahony, Don , Adedayo, Temitope , Adeleke, Olukayode
- Date: 2021
- Subjects: Physicians Erythrocytes--Transfusion Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7989 , vital:57871 , xlink:href="https://doi.org/10.4102/phcfm.v13i1.2889"
- Description: Background: Unnecessary blood transfusion exposes recipients to potential harms. Aim: The aim of this study was to describe blood transfusion practice and explore doctors’ attitudes towards transfusion. Setting: A hospital providing level 1 and 2 services. Methods: A mixed-methods study design was used. In the cross-sectional descriptive component, a sample was taken from patients transfused over a 2-month period. Blood use was categorised as for medical anaemia or haemorrhage, and appropriate or not. The qualitative component comprised a purposeful sample for focus group and individual semistructured interviews. Results: Of 239 patients sampled, 62% were transfused for medical anaemia and 38% for haemorrhage. In the medical anaemia group, compliance with age-appropriate transfusion thresholds was 69%. In medical anaemia and haemorrhage, 114 (77%) and 85 (93.4%) of recipients had orders for ≥ 2 red blood cell (RBC) units, respectively. In adults ≥ 18 years old with medical anaemia, 47.1% of orders would have resulted in a haemoglobin (Hb) > 8 g/dL. Six doctors participated in focus group and eleven in individual interviews. There was a lack of awareness of institutional transfusion guidelines, disagreement on appropriate RBC transfusion thresholds and comments that more than one RBC unit should always be transfused. Factors informing decisions to transfuse included advice from senior colleagues, relieving symptoms of anaemia and high product costs. Conclusion: Most orders were for two or more units. In medical anaemia, doctors’ compliance with RBC transfusion thresholds was reasonable; however, almost half of the orders would have resulted in overtransfusion. The attitudes of doctors sampled suggest that their transfusion practice is influenced more by institutional values than formal guidelines. Keywords: red blood cell transfusion; doctors’ attitudes; doctors’ practice; transfusion thresholds; overtransfusion; descriptive study; qualitative study.
- Full Text:
- Date Issued: 2021
- Authors: O’Mahony, Don , Adedayo, Temitope , Adeleke, Olukayode
- Date: 2021
- Subjects: Physicians Erythrocytes--Transfusion Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7989 , vital:57871 , xlink:href="https://doi.org/10.4102/phcfm.v13i1.2889"
- Description: Background: Unnecessary blood transfusion exposes recipients to potential harms. Aim: The aim of this study was to describe blood transfusion practice and explore doctors’ attitudes towards transfusion. Setting: A hospital providing level 1 and 2 services. Methods: A mixed-methods study design was used. In the cross-sectional descriptive component, a sample was taken from patients transfused over a 2-month period. Blood use was categorised as for medical anaemia or haemorrhage, and appropriate or not. The qualitative component comprised a purposeful sample for focus group and individual semistructured interviews. Results: Of 239 patients sampled, 62% were transfused for medical anaemia and 38% for haemorrhage. In the medical anaemia group, compliance with age-appropriate transfusion thresholds was 69%. In medical anaemia and haemorrhage, 114 (77%) and 85 (93.4%) of recipients had orders for ≥ 2 red blood cell (RBC) units, respectively. In adults ≥ 18 years old with medical anaemia, 47.1% of orders would have resulted in a haemoglobin (Hb) > 8 g/dL. Six doctors participated in focus group and eleven in individual interviews. There was a lack of awareness of institutional transfusion guidelines, disagreement on appropriate RBC transfusion thresholds and comments that more than one RBC unit should always be transfused. Factors informing decisions to transfuse included advice from senior colleagues, relieving symptoms of anaemia and high product costs. Conclusion: Most orders were for two or more units. In medical anaemia, doctors’ compliance with RBC transfusion thresholds was reasonable; however, almost half of the orders would have resulted in overtransfusion. The attitudes of doctors sampled suggest that their transfusion practice is influenced more by institutional values than formal guidelines. Keywords: red blood cell transfusion; doctors’ attitudes; doctors’ practice; transfusion thresholds; overtransfusion; descriptive study; qualitative study.
- Full Text:
- Date Issued: 2021
Doctors’ practice and attitudes towards red blood cell transfusion at Mthatha Regional Hospital, Eastern Cape, South Africa: A mixed methods study
- Mabunda, Sikhumbuzo A, O’Mahony, Don, Adedayo, Temitope, Adeleke, Olukayode
- Authors: Mabunda, Sikhumbuzo A , O’Mahony, Don , Adedayo, Temitope , Adeleke, Olukayode
- Date: 2021
- Subjects: Physicians Erythrocytes--Transfusion Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7216 , vital:53088 , xlink:href="https://doi.org/10.4102/phcfm.v13i1.2889"
- Description: Background: Unnecessary blood transfusion exposes recipients to potential harms. Aim: The aim of this study was to describe blood transfusion practice and explore doctors’ attitudes towards transfusion. Setting: A hospital providing level 1 and 2 services. Methods: A mixed-methods study design was used. In the cross-sectional descriptive component, a sample was taken from patients transfused over a 2-month period. Blood use was categorised as for medical anaemia or haemorrhage, and appropriate or not. The qualitative component comprised a purposeful sample for focus group and individual semistructured interviews. Results: Of 239 patients sampled, 62% were transfused for medical anaemia and 38% for haemorrhage. In the medical anaemia group, compliance with age-appropriate transfusion thresholds was 69%. In medical anaemia and haemorrhage, 114 (77%) and 85 (93.4%) of recipients had orders for ≥ 2 red blood cell (RBC) units, respectively. In adults ≥ 18 years old with medical anaemia, 47.1% of orders would have resulted in a haemoglobin (Hb) > 8 g/dL. Six doctors participated in focus group and eleven in individual interviews. There was a lack of awareness of institutional transfusion guidelines, disagreement on appropriate RBC transfusion thresholds and comments that more than one RBC unit should always be transfused. Factors informing decisions to transfuse included advice from senior colleagues, relieving symptoms of anaemia and high product costs. Conclusion: Most orders were for two or more units. In medical anaemia, doctors’ compliance with RBC transfusion thresholds was reasonable; however, almost half of the orders would have resulted in overtransfusion. The attitudes of doctors sampled suggest that their transfusion practice is influenced more by institutional values than formal guidelines. Keywords: red blood cell transfusion; doctors’ attitudes; doctors’ practice; transfusion thresholds; overtransfusion; descriptive study; qualitative study.
- Full Text:
- Date Issued: 2021
- Authors: Mabunda, Sikhumbuzo A , O’Mahony, Don , Adedayo, Temitope , Adeleke, Olukayode
- Date: 2021
- Subjects: Physicians Erythrocytes--Transfusion Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7216 , vital:53088 , xlink:href="https://doi.org/10.4102/phcfm.v13i1.2889"
- Description: Background: Unnecessary blood transfusion exposes recipients to potential harms. Aim: The aim of this study was to describe blood transfusion practice and explore doctors’ attitudes towards transfusion. Setting: A hospital providing level 1 and 2 services. Methods: A mixed-methods study design was used. In the cross-sectional descriptive component, a sample was taken from patients transfused over a 2-month period. Blood use was categorised as for medical anaemia or haemorrhage, and appropriate or not. The qualitative component comprised a purposeful sample for focus group and individual semistructured interviews. Results: Of 239 patients sampled, 62% were transfused for medical anaemia and 38% for haemorrhage. In the medical anaemia group, compliance with age-appropriate transfusion thresholds was 69%. In medical anaemia and haemorrhage, 114 (77%) and 85 (93.4%) of recipients had orders for ≥ 2 red blood cell (RBC) units, respectively. In adults ≥ 18 years old with medical anaemia, 47.1% of orders would have resulted in a haemoglobin (Hb) > 8 g/dL. Six doctors participated in focus group and eleven in individual interviews. There was a lack of awareness of institutional transfusion guidelines, disagreement on appropriate RBC transfusion thresholds and comments that more than one RBC unit should always be transfused. Factors informing decisions to transfuse included advice from senior colleagues, relieving symptoms of anaemia and high product costs. Conclusion: Most orders were for two or more units. In medical anaemia, doctors’ compliance with RBC transfusion thresholds was reasonable; however, almost half of the orders would have resulted in overtransfusion. The attitudes of doctors sampled suggest that their transfusion practice is influenced more by institutional values than formal guidelines. Keywords: red blood cell transfusion; doctors’ attitudes; doctors’ practice; transfusion thresholds; overtransfusion; descriptive study; qualitative study.
- Full Text:
- Date Issued: 2021
Editorial
- Authors: Rosenberg, Eureta
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389759 , vital:68481 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/216901"
- Description: This issue of the Southern African Journal of Environmental Education coincides with the start of the 26th United Nations Conference on Climate Change. COP26 in Glasgow is, like its predecessors, a Conference of Parties who will deliberate how to lower global greenhouse emissions and build adaptive capacity so as to reduce the risk and impacts of climate change.
- Full Text:
- Date Issued: 2021
- Authors: Rosenberg, Eureta
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/389759 , vital:68481 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/216901"
- Description: This issue of the Southern African Journal of Environmental Education coincides with the start of the 26th United Nations Conference on Climate Change. COP26 in Glasgow is, like its predecessors, a Conference of Parties who will deliberate how to lower global greenhouse emissions and build adaptive capacity so as to reduce the risk and impacts of climate change.
- Full Text:
- Date Issued: 2021
Effect of ultrasonic frequency and power on the sonodynamic therapy activity of cationic Zn (II) phthalocyanines
- Nene, Lindokuhle C, Sindelo, Azole, Britton, Jonathan, Nyokong, Tebello
- Authors: Nene, Lindokuhle C , Sindelo, Azole , Britton, Jonathan , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185737 , vital:44419 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111397"
- Description: We report on the sonodynamic activity of cationic phthalocyanines (Pcs) and the effect of the variation of two parameters: ultrasound frequency and power (Par I (1 MHz, 1 W cm−2), Par II (1 MHz, 2 W cm−2), Par III (3 MHz, 1 W cm−2) and Par IV (3 MHz, 2 W cm−2)) on the efficiency of their reactive oxygen species generation and cancer eradication in vitro thereof. Where Par stands for the various combinations of these parameters. Four Pcs were investigated with substituents bearing diethylamine, ortho- and para-pyridine and morpholine groups. Overall, the para-pyridine and morpholine Pcs showed substantial sono-activity in the various ultrasound parameters with Par I and IV generally showing better singlet oxygen and hydroxyl radicals generation confirmed by electron paramagnetic resonance spectroscopy. In some cases, very high hydroxyl radicals' generation was observed at Par II. Furthermore, the fragmentation of the Pcs after Par II treatments was confirmed using UV–vis and magnetic circular dichroism spectroscopy. The reactive species generation efficacy decreased at Par III for all samples. Ultrasound assisted cytotoxicity of the Pcs was confirmed in vitro using the human (Michigan Cancer Foundation-7) breast cancer cell line.
- Full Text:
- Date Issued: 2021
- Authors: Nene, Lindokuhle C , Sindelo, Azole , Britton, Jonathan , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185737 , vital:44419 , xlink:href="https://doi.org/10.1016/j.jinorgbio.2021.111397"
- Description: We report on the sonodynamic activity of cationic phthalocyanines (Pcs) and the effect of the variation of two parameters: ultrasound frequency and power (Par I (1 MHz, 1 W cm−2), Par II (1 MHz, 2 W cm−2), Par III (3 MHz, 1 W cm−2) and Par IV (3 MHz, 2 W cm−2)) on the efficiency of their reactive oxygen species generation and cancer eradication in vitro thereof. Where Par stands for the various combinations of these parameters. Four Pcs were investigated with substituents bearing diethylamine, ortho- and para-pyridine and morpholine groups. Overall, the para-pyridine and morpholine Pcs showed substantial sono-activity in the various ultrasound parameters with Par I and IV generally showing better singlet oxygen and hydroxyl radicals generation confirmed by electron paramagnetic resonance spectroscopy. In some cases, very high hydroxyl radicals' generation was observed at Par II. Furthermore, the fragmentation of the Pcs after Par II treatments was confirmed using UV–vis and magnetic circular dichroism spectroscopy. The reactive species generation efficacy decreased at Par III for all samples. Ultrasound assisted cytotoxicity of the Pcs was confirmed in vitro using the human (Michigan Cancer Foundation-7) breast cancer cell line.
- Full Text:
- Date Issued: 2021
Efforts towards engaging communities to promote the benefits of biological control research and implementation in South Africa
- Weaver, Kim N, Hill, Martin P, Byrne, Marcus J, Ivey, Philip J
- Authors: Weaver, Kim N , Hill, Martin P , Byrne, Marcus J , Ivey, Philip J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414428 , vital:71146 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a23"
- Description: In the last decade, biological control in South Africa has evolved from a classical applied science, allied to an extension service, to a more community engagement-based activity. Therefore, capacity building is important for the sustainability of biological control research and its implementation. In South Africa, a broad approach has been taken to build capacity in weed biological control, starting at grass-roots level with primary and secondary school learner programmes, through to developing research capacity at the tertiary level and enhancing technical capacity through adult education. Non-specialists are empowered through access to knowledge. The dissemination of accurate information through the most appropriate outlets has become increasingly important, including non-traditional science communication through the internet and, more importantly, social media, which has the potential to reach a far wider audience. Public understanding of biological control has the potential to contribute significantly to the green and knowledge economies of South Africa, but relies on government support for the sustainability of this discipline.
- Full Text:
- Date Issued: 2021
- Authors: Weaver, Kim N , Hill, Martin P , Byrne, Marcus J , Ivey, Philip J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414428 , vital:71146 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a23"
- Description: In the last decade, biological control in South Africa has evolved from a classical applied science, allied to an extension service, to a more community engagement-based activity. Therefore, capacity building is important for the sustainability of biological control research and its implementation. In South Africa, a broad approach has been taken to build capacity in weed biological control, starting at grass-roots level with primary and secondary school learner programmes, through to developing research capacity at the tertiary level and enhancing technical capacity through adult education. Non-specialists are empowered through access to knowledge. The dissemination of accurate information through the most appropriate outlets has become increasingly important, including non-traditional science communication through the internet and, more importantly, social media, which has the potential to reach a far wider audience. Public understanding of biological control has the potential to contribute significantly to the green and knowledge economies of South Africa, but relies on government support for the sustainability of this discipline.
- Full Text:
- Date Issued: 2021
Electrocatalytic Activity of Cobalt Phthalocyanines Revisited: Effect of the Number of Oxygen Atoms and Conjugation to Carbon Nanomaterials
- Ndebele, Nobuhle, Mgidlana, Sithi, Nyokong, Tebello
- Authors: Ndebele, Nobuhle , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185700 , vital:44416 , xlink:href="https://doi.org/10.1007/s12678-021-00670-x"
- Description: The synthesis and characterization of tetrakis[4(4-acetlyphenoxy)phthalocyanato] cobalt (II) (1) are presented. Complex 1 together with the reported tetrakis dimethyl 5-(phenoxy)-isophthalatephthalocyaninato] cobalt (II) (2) are conjugated to carbon-based nanomaterials: graphene quantum dots (GQDs) and single-walled carbon nanotubes (SWCNTs) via π-π stacking, taking advantage of the π electrons on the graphitic structure of the nanomaterial as well as on the aromatic rings of the Co phthalocyanines (CoPcs). The electrocatalytic behaviour of the CoPcs, GQDs, SWCNTs and their respective conjugates towards the electrochemical oxidation of catechol was studied. The electrocatalytic probes were drop-dried onto the electrode surface of the glassy carbon electrode (GCE). The electrochemical oxidation of catechol was studied using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Complex 2 when linked to GQDs gave the lowest oxidation peak potentials of 0.33 V. Low catechol detection limits (LOD) of 0.057 µM was obtained for complex 2 with SWCNT. Thus, complex 2 containing more oxygen atoms outperformed complex 1 with less oxygen atoms. The CoPcs on their own showed moderate electrocatalytic behaviour, hence showing the importance of conjugating them to the carbon nanomaterials. SWCNT-based electrodes performed better than GQDs, and an improvement in the LoDs, sensitivity and the catalytic rate was observed upon conjugation.
- Full Text:
- Date Issued: 2021
- Authors: Ndebele, Nobuhle , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185700 , vital:44416 , xlink:href="https://doi.org/10.1007/s12678-021-00670-x"
- Description: The synthesis and characterization of tetrakis[4(4-acetlyphenoxy)phthalocyanato] cobalt (II) (1) are presented. Complex 1 together with the reported tetrakis dimethyl 5-(phenoxy)-isophthalatephthalocyaninato] cobalt (II) (2) are conjugated to carbon-based nanomaterials: graphene quantum dots (GQDs) and single-walled carbon nanotubes (SWCNTs) via π-π stacking, taking advantage of the π electrons on the graphitic structure of the nanomaterial as well as on the aromatic rings of the Co phthalocyanines (CoPcs). The electrocatalytic behaviour of the CoPcs, GQDs, SWCNTs and their respective conjugates towards the electrochemical oxidation of catechol was studied. The electrocatalytic probes were drop-dried onto the electrode surface of the glassy carbon electrode (GCE). The electrochemical oxidation of catechol was studied using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Complex 2 when linked to GQDs gave the lowest oxidation peak potentials of 0.33 V. Low catechol detection limits (LOD) of 0.057 µM was obtained for complex 2 with SWCNT. Thus, complex 2 containing more oxygen atoms outperformed complex 1 with less oxygen atoms. The CoPcs on their own showed moderate electrocatalytic behaviour, hence showing the importance of conjugating them to the carbon nanomaterials. SWCNT-based electrodes performed better than GQDs, and an improvement in the LoDs, sensitivity and the catalytic rate was observed upon conjugation.
- Full Text:
- Date Issued: 2021
Electrocatalytic activity of manganese tetra 4-aminophenyl porphyrin in the presence of graphene quantum dots
- Jokzai, Mbulelo, Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Jokzai, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231443 , vital:49888 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: A manganese tetra 4-aminophenyl porphyrin (MnTAPP) was synthesized and attached to graphene quantum dots (GQDs) via covalent and π-π interaction to give MnTAPP@GQDs and MnTAPP--GQDs, respectively. There was an increase (using dynamic light scattering and transmission electron microscopy) in size of the GQDs in the presence of the porphyrin due to aggregation. The porphyrins in the absence and presence of GQDs were then adsorbed onto a glassy carbon electrode using drop and dry method. The electrochemical behavior was tested by cyclic voltammetry and chronoamperometry towards hydrazine. Both methods of combining MnTAPP with GQDs improved the activity of the electrocatalysis compared to individual components. MnTAPP@GQDs showed better catalytic rate constant of 4.36 × 102 Ms−1 and lowest LoD of 0.0023 mM followed by MnTAPP--GQDs. Furthermore, the sensor showed good selectivity in the presence of interfering analytes. All probes showed good stability.
- Full Text:
- Date Issued: 2021
- Authors: Jokzai, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231443 , vital:49888 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.02.040"
- Description: A manganese tetra 4-aminophenyl porphyrin (MnTAPP) was synthesized and attached to graphene quantum dots (GQDs) via covalent and π-π interaction to give MnTAPP@GQDs and MnTAPP--GQDs, respectively. There was an increase (using dynamic light scattering and transmission electron microscopy) in size of the GQDs in the presence of the porphyrin due to aggregation. The porphyrins in the absence and presence of GQDs were then adsorbed onto a glassy carbon electrode using drop and dry method. The electrochemical behavior was tested by cyclic voltammetry and chronoamperometry towards hydrazine. Both methods of combining MnTAPP with GQDs improved the activity of the electrocatalysis compared to individual components. MnTAPP@GQDs showed better catalytic rate constant of 4.36 × 102 Ms−1 and lowest LoD of 0.0023 mM followed by MnTAPP--GQDs. Furthermore, the sensor showed good selectivity in the presence of interfering analytes. All probes showed good stability.
- Full Text:
- Date Issued: 2021