Technology Adoption Readiness in Disadvantaged Universities during COVID 19 Pandemic in South Africa
- Aruleba, Kehinde., Jere, Nobert., Matarirano, Obert.
- Authors: Aruleba, Kehinde. , Jere, Nobert. , Matarirano, Obert.
- Date: 2022
- Subjects: Covid 19 Readiness for school Web-based instruction Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6544 , vital:46489 , xlink:href="https://doi.org/10.5430/ijhe.v11n2p172"
- Description: The Covid 19 pandemic has affected hundreds of million lives and taken over four million lives to date. As a result, governments and policymakers see the need for emergency action to reduce the spread of the virus. In an attempt to contain the virus, governments and policymakers worldwide introduced a different range of prote ction measures and interventions to change their citizen's behaviours , primarily through social distancing, interprovince lockdown, stay at home strategies, and quarantines. The different lockdown measures have created unique and challenging conditions wit h no documented equivalent in the education sector. A significant effect was that many Higher Education institutions worldwide were not ready to switch to online teaching and learning when the governments announced the sudden lockdown. This study discusses the effect s of the Covid 19 pandemic on South Africa Higher Education Institution s , focusing on the historically disadvantaged universities. The study went further to evaluate the readiness of lecturers from selected disadvantaged universities to adopting online teaching and learning by applying the Technology Readiness Acceptance Model (TRAM). Quantitative data was collected through an online questionnaire. Results show that the higher the average of optimism and innovativeness among the respondents' poin t towards the readiness of adopting technology. On the other hand, higher the average insecurity and discomfort show the uneasiness of adopting technologies by the respondents.
- Full Text:
- Date Issued: 2022
Technology Adoption Readiness in Disadvantaged Universities during COVID 19 Pandemic in South Africa
- Authors: Aruleba, Kehinde. , Jere, Nobert. , Matarirano, Obert.
- Date: 2022
- Subjects: Covid 19 Readiness for school Web-based instruction Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6544 , vital:46489 , xlink:href="https://doi.org/10.5430/ijhe.v11n2p172"
- Description: The Covid 19 pandemic has affected hundreds of million lives and taken over four million lives to date. As a result, governments and policymakers see the need for emergency action to reduce the spread of the virus. In an attempt to contain the virus, governments and policymakers worldwide introduced a different range of prote ction measures and interventions to change their citizen's behaviours , primarily through social distancing, interprovince lockdown, stay at home strategies, and quarantines. The different lockdown measures have created unique and challenging conditions wit h no documented equivalent in the education sector. A significant effect was that many Higher Education institutions worldwide were not ready to switch to online teaching and learning when the governments announced the sudden lockdown. This study discusses the effect s of the Covid 19 pandemic on South Africa Higher Education Institution s , focusing on the historically disadvantaged universities. The study went further to evaluate the readiness of lecturers from selected disadvantaged universities to adopting online teaching and learning by applying the Technology Readiness Acceptance Model (TRAM). Quantitative data was collected through an online questionnaire. Results show that the higher the average of optimism and innovativeness among the respondents' poin t towards the readiness of adopting technology. On the other hand, higher the average insecurity and discomfort show the uneasiness of adopting technologies by the respondents.
- Full Text:
- Date Issued: 2022
The (Slow) Urgency of Socio-cological Justice in ESE–Listening to Children in Marginalized Positions in ESE
- Jørgensen, Nanna J, James, Anna
- Authors: Jørgensen, Nanna J , James, Anna
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437526 , vital:73391 , ISBN
- Description: As a contribution to discussions about how ESE research respond to increasing urgency and climate emergencies, this essay discusses the relation between education and the pursuit of societal transformation with a view to questions of socio-ecological justice. Our research interest centers on young children’s participation and voice, on the inequalities which constitute barriers to this participation, and on the potentials of a more fine-tuned pedagogy which listens to children’s voices and their relations with the non-human environment in our research practices. This listening is a radical process of unlearning and rethinking ‘urgency’. The essay is based on an ongoing dialogue about how research on sustainability education might respond to the voices of children in marginalized positions across two very different geographical and socio-cultural settings–the Danish welfare state and post-apartheid South Africa (see James and Jørgensen, forthcoming). Here we draw attention to the dangers of assumptions underlying urgency (dualism and instrumentalism) and the voices of young children in research as a practice that resists these dangers.
- Full Text:
- Date Issued: 2022
- Authors: Jørgensen, Nanna J , James, Anna
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437526 , vital:73391 , ISBN
- Description: As a contribution to discussions about how ESE research respond to increasing urgency and climate emergencies, this essay discusses the relation between education and the pursuit of societal transformation with a view to questions of socio-ecological justice. Our research interest centers on young children’s participation and voice, on the inequalities which constitute barriers to this participation, and on the potentials of a more fine-tuned pedagogy which listens to children’s voices and their relations with the non-human environment in our research practices. This listening is a radical process of unlearning and rethinking ‘urgency’. The essay is based on an ongoing dialogue about how research on sustainability education might respond to the voices of children in marginalized positions across two very different geographical and socio-cultural settings–the Danish welfare state and post-apartheid South Africa (see James and Jørgensen, forthcoming). Here we draw attention to the dangers of assumptions underlying urgency (dualism and instrumentalism) and the voices of young children in research as a practice that resists these dangers.
- Full Text:
- Date Issued: 2022
The contribution of wild palms to the livelihoods and diversification of rural households in southern Mozambique
- King, Angelina R, Shackleton, Charlie M
- Authors: King, Angelina R , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399846 , vital:69563 , xlink:href="https://doi.org/10.1016/j.forpol.2022.102793"
- Description: In most low-income countries, rural households combine a range of economic activities to generate income, achieve food and nutritional security and fulfill other livelihood objectives, including: small-scale farming, fishing, hunting, livestock and timber production, and non-timber forest products gathering, as well as off-farm activities such as wage labour and informal trading. This work examines the role of diversification, including palm products income, on rural livelihoods in the Zitundo area, southern Mozambique. Seven livelihood strategies were identified, with every strategy combining cash income from several sources. Most households adopt a wage-based strategy to some degree, although this strategy shows low potential for reducing poverty in the area. Households adopting a palm-based strategy show between 23% and 60% lower poverty incidence than those adopting alternatives strategies. Yet, a palm-based livelihood strategy was adopted by only 11% of households. Traders of palm products earn approximately double the annual income and per capita income than non-traders. Village of residency and some household socio-economic and demographic characteristics correlate with a households' choice of livelihood strategy and palm income dependency. The adherence of many households to a less remunerative wage strategy indicates other factors also influence the choice of livelihood strategies. The study shows that future development plans and policy interventions to mitigate poverty in the area should go beyond the usual agricultural sector and recognize the role of non-timber forest products, especially palm products, for people's livelihoods and poverty alleviation.
- Full Text:
- Date Issued: 2022
- Authors: King, Angelina R , Shackleton, Charlie M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/399846 , vital:69563 , xlink:href="https://doi.org/10.1016/j.forpol.2022.102793"
- Description: In most low-income countries, rural households combine a range of economic activities to generate income, achieve food and nutritional security and fulfill other livelihood objectives, including: small-scale farming, fishing, hunting, livestock and timber production, and non-timber forest products gathering, as well as off-farm activities such as wage labour and informal trading. This work examines the role of diversification, including palm products income, on rural livelihoods in the Zitundo area, southern Mozambique. Seven livelihood strategies were identified, with every strategy combining cash income from several sources. Most households adopt a wage-based strategy to some degree, although this strategy shows low potential for reducing poverty in the area. Households adopting a palm-based strategy show between 23% and 60% lower poverty incidence than those adopting alternatives strategies. Yet, a palm-based livelihood strategy was adopted by only 11% of households. Traders of palm products earn approximately double the annual income and per capita income than non-traders. Village of residency and some household socio-economic and demographic characteristics correlate with a households' choice of livelihood strategy and palm income dependency. The adherence of many households to a less remunerative wage strategy indicates other factors also influence the choice of livelihood strategies. The study shows that future development plans and policy interventions to mitigate poverty in the area should go beyond the usual agricultural sector and recognize the role of non-timber forest products, especially palm products, for people's livelihoods and poverty alleviation.
- Full Text:
- Date Issued: 2022
The effect of charge on Zn tetra morpholine porphyrin conjugated to folic acid-nitrogen doped graphene quantum dots for photodynamic therapy studies
- Magaela, N Bridged, Matshitse, Refilwe, Nyokong, Tebello
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295840 , vital:57383 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102898"
- Description: Zinc tetra morpholine porphyrin (complex 2), and its quaternized derivative (complex 3) were synthesized and conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs) through π−π stacking to study their photodynamic therapy (PDT) efficacy. Photophysiochemical properties of complexes 2, 3, and their conjugates (2-FA-NGQDs, 3-FA-NGQDs) were studied. It was found that complex 3 had higher ϕΔ of 0.56 compared to complex 2 with ϕΔ of 0.24, and respective composites: 3-FA-NGQDs had higher ϕΔ compared to 2-FA-NGQDs. The PDT studies were conducted for nanoparticles (FA-NGQDs), complexes (2, 3), and respective composites (2-FA-NGQDs, and 3-FA-NGQDs) using MCF-7 breast cancer cell. Dark toxicity of all compounds was above 90% which is negligible. At a highest concentration of 40 µg/mL, 3-FA-NGQDs gave the lowest cell viability of 28% compared to all other conjugates and porphyrins alone.
- Full Text:
- Date Issued: 2022
- Authors: Magaela, N Bridged , Matshitse, Refilwe , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295840 , vital:57383 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.102898"
- Description: Zinc tetra morpholine porphyrin (complex 2), and its quaternized derivative (complex 3) were synthesized and conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs) through π−π stacking to study their photodynamic therapy (PDT) efficacy. Photophysiochemical properties of complexes 2, 3, and their conjugates (2-FA-NGQDs, 3-FA-NGQDs) were studied. It was found that complex 3 had higher ϕΔ of 0.56 compared to complex 2 with ϕΔ of 0.24, and respective composites: 3-FA-NGQDs had higher ϕΔ compared to 2-FA-NGQDs. The PDT studies were conducted for nanoparticles (FA-NGQDs), complexes (2, 3), and respective composites (2-FA-NGQDs, and 3-FA-NGQDs) using MCF-7 breast cancer cell. Dark toxicity of all compounds was above 90% which is negligible. At a highest concentration of 40 µg/mL, 3-FA-NGQDs gave the lowest cell viability of 28% compared to all other conjugates and porphyrins alone.
- Full Text:
- Date Issued: 2022
The Electrocatalytic Detection of Nitrite Using Manganese Schiff Base Phthalocyanine Complexes
- Ndebele, Nobuhle, Nyokong, Tebello
- Authors: Ndebele, Nobuhle , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295856 , vital:57385 , xlink:href="https://doi.org/10.1007/s12678-022-00752-4"
- Description: This work investigates the use of manganese phthalocyanines (MnPcs) in the electrochemical detection of nitrite. These are two Schiff base derivatives: tetrakis 4-(4-thio-thiophene-2-ylmethanamino) phthalocyaninato Mn(III)Cl (2) and tetrakis 4-(3-(pyrrolidine-1-yl)propan-1-amino)phthalocyaninato Mn(III)Cl (3) and one aldehyde: tetrakis(4-formylphenoxy)phthalocyaninato Mn(III)Cl (1). The MnPc complexes were adsorbed onto the glassy carbon electrode surface using the drop-dry method and used as electrocatalysts to detect nitrite. Nitrite oxidation peak potentials obtained using cyclic voltammetry ranged between 0.70 and 0.84 V. Detection limits as low as 0.16 µM and sensitivity values as high as 276 µMmM−1 were obtained through the use of chronoamperometry. The Schiff base MnPcs 2 and 3 exhibited better nitrite detection properties (in terms of limit of detection and sensitivity) than their aldehyde precursor (1).
- Full Text:
- Date Issued: 2022
- Authors: Ndebele, Nobuhle , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295856 , vital:57385 , xlink:href="https://doi.org/10.1007/s12678-022-00752-4"
- Description: This work investigates the use of manganese phthalocyanines (MnPcs) in the electrochemical detection of nitrite. These are two Schiff base derivatives: tetrakis 4-(4-thio-thiophene-2-ylmethanamino) phthalocyaninato Mn(III)Cl (2) and tetrakis 4-(3-(pyrrolidine-1-yl)propan-1-amino)phthalocyaninato Mn(III)Cl (3) and one aldehyde: tetrakis(4-formylphenoxy)phthalocyaninato Mn(III)Cl (1). The MnPc complexes were adsorbed onto the glassy carbon electrode surface using the drop-dry method and used as electrocatalysts to detect nitrite. Nitrite oxidation peak potentials obtained using cyclic voltammetry ranged between 0.70 and 0.84 V. Detection limits as low as 0.16 µM and sensitivity values as high as 276 µMmM−1 were obtained through the use of chronoamperometry. The Schiff base MnPcs 2 and 3 exhibited better nitrite detection properties (in terms of limit of detection and sensitivity) than their aldehyde precursor (1).
- Full Text:
- Date Issued: 2022
The emergence of isiZulu in Skeem Saam (2011)
- Authors: Aiseng, Kealeboga
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/277956 , vital:55335 , xlink:href="https://doi.org/10.1080/13504630.2022.2063115"
- Description: This study aims to investigate how an ecological understanding of polyglossia is used in the South African Broadcasting Corporation’s (SABC) television channel, SABC 1 to maintain and create ethnolinguistic dominance. Key arguments this study will make are: (1) polyglossia is a language ideology masquerading as ethnolinguistic pluralism, (2) there is a loss of ethnolinguistic pluralism in SABC 1 because of the polyglot culture and its transmissions, (3) isiZulu is emerging as a language and cultural flare of the channel. This paper concluded that isiZulu’s presence is rising in a soap initially meant to be a Sepedi show. And this has negative consequences for language equality in the SABC.
- Full Text:
- Date Issued: 2022
- Authors: Aiseng, Kealeboga
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/277956 , vital:55335 , xlink:href="https://doi.org/10.1080/13504630.2022.2063115"
- Description: This study aims to investigate how an ecological understanding of polyglossia is used in the South African Broadcasting Corporation’s (SABC) television channel, SABC 1 to maintain and create ethnolinguistic dominance. Key arguments this study will make are: (1) polyglossia is a language ideology masquerading as ethnolinguistic pluralism, (2) there is a loss of ethnolinguistic pluralism in SABC 1 because of the polyglot culture and its transmissions, (3) isiZulu is emerging as a language and cultural flare of the channel. This paper concluded that isiZulu’s presence is rising in a soap initially meant to be a Sepedi show. And this has negative consequences for language equality in the SABC.
- Full Text:
- Date Issued: 2022
The extent and impact of variation in ADME genes in sub-Saharan African populations
- da Rocha, Jorge E B, Othman, Houcemeddine, Botha, Gerrit, Cottino, Laura, Twesigomwe, David, Ahmed, Samah, Drögemöller, Britt I, Fadlelmola, Faisal M, Machanick, Philip, Mbiyavanga, Mamana, Panji, Sumir, Wright, Galen E B, Adebamowo, Clement, Matshaba, Mogomotsi, Ramsay, Michéle, Simo, Gustave, Simuunza, Martin C, Tiemessen, Caroline T, Baldwin, Sandra, Chiano, Mathias, Cox, Charles, Gross, Annette S, Thomas, Pamela, Gamo, Francisco-Javier, Scott Hazelhurst
- Authors: da Rocha, Jorge E B , Othman, Houcemeddine , Botha, Gerrit , Cottino, Laura , Twesigomwe, David , Ahmed, Samah , Drögemöller, Britt I , Fadlelmola, Faisal M , Machanick, Philip , Mbiyavanga, Mamana , Panji, Sumir , Wright, Galen E B , Adebamowo, Clement , Matshaba, Mogomotsi , Ramsay, Michéle , Simo, Gustave , Simuunza, Martin C , Tiemessen, Caroline T , Baldwin, Sandra , Chiano, Mathias , Cox, Charles , Gross, Annette S , Thomas, Pamela , Gamo, Francisco-Javier , Scott Hazelhurst
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439202 , vital:73555 , https://homes.cs.ru.ac.za/philip/Courses/CSHonsArch/HonsArchNotes2022.pdf
- Description: Investigating variation in genes involved in the absorption, distribution, metabolism, and excretion (ADME) of drugs are key to characterizing pharmacogenomic (PGx) relationships. ADME gene variation is relatively well characterized in European and Asian populations, but data from African populations are under-studied—which has implications for drug safety and effective use in Africa.
- Full Text:
- Date Issued: 2022
- Authors: da Rocha, Jorge E B , Othman, Houcemeddine , Botha, Gerrit , Cottino, Laura , Twesigomwe, David , Ahmed, Samah , Drögemöller, Britt I , Fadlelmola, Faisal M , Machanick, Philip , Mbiyavanga, Mamana , Panji, Sumir , Wright, Galen E B , Adebamowo, Clement , Matshaba, Mogomotsi , Ramsay, Michéle , Simo, Gustave , Simuunza, Martin C , Tiemessen, Caroline T , Baldwin, Sandra , Chiano, Mathias , Cox, Charles , Gross, Annette S , Thomas, Pamela , Gamo, Francisco-Javier , Scott Hazelhurst
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/439202 , vital:73555 , https://homes.cs.ru.ac.za/philip/Courses/CSHonsArch/HonsArchNotes2022.pdf
- Description: Investigating variation in genes involved in the absorption, distribution, metabolism, and excretion (ADME) of drugs are key to characterizing pharmacogenomic (PGx) relationships. ADME gene variation is relatively well characterized in European and Asian populations, but data from African populations are under-studied—which has implications for drug safety and effective use in Africa.
- Full Text:
- Date Issued: 2022
The first ‘Grylloblattida’of the family Liomopteridae from the Middle Permian in the Onder Karoo, South Africa (Insecta Polyneoptera)
- Cawood, Rebecca, Nel, Andre, Garrouste, Romaine, Moyo, Sydney, Villet, Martin H, Prevec, Rosemary
- Authors: Cawood, Rebecca , Nel, Andre , Garrouste, Romaine , Moyo, Sydney , Villet, Martin H , Prevec, Rosemary
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440723 , vital:73807 , https://hal.science/mnhn-04019993/
- Description: Here we describe a new genus and four new species of the extinct ‘Grylloblattida’: Liomopteridae Sellards, 1909: Liomopterum connexus Cawood and Nel, n. sp., Liomopterum daenerys Cawood and Nel, n. sp., Colubrosopterum karooensis Cawood and Nel, n. gen., n. sp., and Paraliomopterum sp. The fossil wings were collected from a new Middle Permian locality near Sutherland, Northern Cape, South Africa, with the horizon close to the Ecca-Beaufort Group contact in the southern Karoo Basin.
- Full Text:
- Date Issued: 2022
- Authors: Cawood, Rebecca , Nel, Andre , Garrouste, Romaine , Moyo, Sydney , Villet, Martin H , Prevec, Rosemary
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440723 , vital:73807 , https://hal.science/mnhn-04019993/
- Description: Here we describe a new genus and four new species of the extinct ‘Grylloblattida’: Liomopteridae Sellards, 1909: Liomopterum connexus Cawood and Nel, n. sp., Liomopterum daenerys Cawood and Nel, n. sp., Colubrosopterum karooensis Cawood and Nel, n. gen., n. sp., and Paraliomopterum sp. The fossil wings were collected from a new Middle Permian locality near Sutherland, Northern Cape, South Africa, with the horizon close to the Ecca-Beaufort Group contact in the southern Karoo Basin.
- Full Text:
- Date Issued: 2022
The genetic architecture of the corpus callosum and its subregions
- Campbell, Megan, Dalvie, Shareefa, Shadrin, Alexey, van der Meer, Dennis, Andreassen, Ola, Stein, Dan J, Rokicki, Jaroslav
- Authors: Campbell, Megan , Dalvie, Shareefa , Shadrin, Alexey , van der Meer, Dennis , Andreassen, Ola , Stein, Dan J , Rokicki, Jaroslav
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302542 , vital:58206 , xlink:href="https://doi.org/10.1016/j.euroneuro.2022.07.263"
- Description: Background: Regional surface area and thickness of the cerebral cortex and volume of subcortical structures are highly heritable brain morphological features with complex genetic architectures, involving many common genetic variants with small effect sizes. However, the genetic architecture of the corpus callosum (CC) and its subregions remains largely unclear. We aim to determine the heritability and genetic architecture of CC volume and each subregion and the extent to which this overlaps with that of psychiatric disorders. Methods: Genetic and T1-weighted MRI data of 40,894 individuals from the UK-biobank was used to construct a multivariate GWAS. Here, we utilized a multivariate approach (Multivariate Omnibus Statistical Test, MOSTest) to assess the distributive effects of common variants across the five subregions of the CC (posterior, mid posterior, central, mid anterior and anterior) obtained by running the automatic subcortical segmentation algorithm in FreeSurfer 5.3. Gene-set enrichment analyses were performed using MAGMA. Linkage disequilibrium score regression was used to determine the SNP-based heritability of the CC and will be used to assess the genetic correlation between each subregion and a variety of psychiatric disorders. Results: Following MOSTest, 70 independent loci show pooled effects across the 5 subregions of the CC (p more than 5×10-8). Using LDSC, we found evidence to suggest that CC volume is heritable (h2SNP= 0.38, SE=0.03). Significant variants showed enrichment in pathways related to regulation of the nervous system and cell development, neurogenesis, and regulation of neuron differentiation. Gene-set analysis revealed 156 significant genes (p is less than 2.6x10-6). Many of the significant SNPs have been previously associated with white matter hyperintensity volume as well as a range of psychiatric disorders. Discussion: Here we provide the first preliminary evidence to suggest that volume of the CC is heritable. Gene set enrichment analyses identified pathways related to neuron development and neurogenesis, suggesting that CC alteration may have an independent developmental origin. Further investigation into the shared genetic architecture of CC subregions and psychiatric disorders may provide novel insight into disease manifestation.
- Full Text:
- Date Issued: 2022
- Authors: Campbell, Megan , Dalvie, Shareefa , Shadrin, Alexey , van der Meer, Dennis , Andreassen, Ola , Stein, Dan J , Rokicki, Jaroslav
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302542 , vital:58206 , xlink:href="https://doi.org/10.1016/j.euroneuro.2022.07.263"
- Description: Background: Regional surface area and thickness of the cerebral cortex and volume of subcortical structures are highly heritable brain morphological features with complex genetic architectures, involving many common genetic variants with small effect sizes. However, the genetic architecture of the corpus callosum (CC) and its subregions remains largely unclear. We aim to determine the heritability and genetic architecture of CC volume and each subregion and the extent to which this overlaps with that of psychiatric disorders. Methods: Genetic and T1-weighted MRI data of 40,894 individuals from the UK-biobank was used to construct a multivariate GWAS. Here, we utilized a multivariate approach (Multivariate Omnibus Statistical Test, MOSTest) to assess the distributive effects of common variants across the five subregions of the CC (posterior, mid posterior, central, mid anterior and anterior) obtained by running the automatic subcortical segmentation algorithm in FreeSurfer 5.3. Gene-set enrichment analyses were performed using MAGMA. Linkage disequilibrium score regression was used to determine the SNP-based heritability of the CC and will be used to assess the genetic correlation between each subregion and a variety of psychiatric disorders. Results: Following MOSTest, 70 independent loci show pooled effects across the 5 subregions of the CC (p more than 5×10-8). Using LDSC, we found evidence to suggest that CC volume is heritable (h2SNP= 0.38, SE=0.03). Significant variants showed enrichment in pathways related to regulation of the nervous system and cell development, neurogenesis, and regulation of neuron differentiation. Gene-set analysis revealed 156 significant genes (p is less than 2.6x10-6). Many of the significant SNPs have been previously associated with white matter hyperintensity volume as well as a range of psychiatric disorders. Discussion: Here we provide the first preliminary evidence to suggest that volume of the CC is heritable. Gene set enrichment analyses identified pathways related to neuron development and neurogenesis, suggesting that CC alteration may have an independent developmental origin. Further investigation into the shared genetic architecture of CC subregions and psychiatric disorders may provide novel insight into disease manifestation.
- Full Text:
- Date Issued: 2022
The implications of ortho-, meta-and para-directors on the in-vitro photodynamic antimicrobial chemotherapy activity of cationic pyridyl-dihydrothiazole phthalocyanines
- Magadla, Aviwe, Openda, Yolande Ikala, Nyokong, Tebello
- Authors: Magadla, Aviwe , Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295875 , vital:57386 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103029"
- Description: Cationic Zn phthalocyanine complexes were derived by alkylation reaction of tetra-(pyridinyloxy) phthalocyanines (Pcs) at the ortho, meta, and para positions to form Zn (II) tetrakis 3-(4-(2-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (2), Zn (II) tetrakis 3-(4-(3-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (4) and Zn (II) tetrakis 3-(4-(4-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (6). The photophysicochemical behaviors of the Pc complexes were assessed. The meta and para-substituted complexes gave high singlet oxygen quantum yields. The cationic Pcs demonstrated good planktonic antibacterial activity against Staphylococcus aureus and Escherichia coli with the high log reduction values of 9.29 and 8.55, respectively. The cationic complexes also showed a significant decrease in the viability of in vitro biofilms after photo-antimicrobial chemotherapy at 100 µM for both Staphylococcus aureus and Escherichia coli biofilms.
- Full Text:
- Date Issued: 2022
- Authors: Magadla, Aviwe , Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295875 , vital:57386 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103029"
- Description: Cationic Zn phthalocyanine complexes were derived by alkylation reaction of tetra-(pyridinyloxy) phthalocyanines (Pcs) at the ortho, meta, and para positions to form Zn (II) tetrakis 3-(4-(2-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (2), Zn (II) tetrakis 3-(4-(3-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (4) and Zn (II) tetrakis 3-(4-(4-pyridin-1-ium-1-yl) butyl)-2-mercapto-4,5-dihydrothiazol-3-ium phthalocyanine (6). The photophysicochemical behaviors of the Pc complexes were assessed. The meta and para-substituted complexes gave high singlet oxygen quantum yields. The cationic Pcs demonstrated good planktonic antibacterial activity against Staphylococcus aureus and Escherichia coli with the high log reduction values of 9.29 and 8.55, respectively. The cationic complexes also showed a significant decrease in the viability of in vitro biofilms after photo-antimicrobial chemotherapy at 100 µM for both Staphylococcus aureus and Escherichia coli biofilms.
- 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
The last two remaining populations of the critically endangered estuarine pipefish are inbred and not genetically distinct
- Weiss, Sven-Erick, Emami-Khoyi, Arsalan, Kaiser, Horst, Cowley, Paul D, James, Nicola C, Jansen van Vuuren, Bettine, Whitfield, Alan K, Teske, Peter R
- Authors: Weiss, Sven-Erick , Emami-Khoyi, Arsalan , Kaiser, Horst , Cowley, Paul D , James, Nicola C , Jansen van Vuuren, Bettine , Whitfield, Alan K , Teske, Peter R
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445101 , vital:74347 , https://doi.org/10.3389/fmars.2021.756595
- Description: Temporary wetland ecosystems are common in arid and semi‐arid envi-ronments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geograph-ically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well-connected population or comprises different regional genetic groups, some of which may be rare or endangered.
- Full Text:
- Date Issued: 2022
- Authors: Weiss, Sven-Erick , Emami-Khoyi, Arsalan , Kaiser, Horst , Cowley, Paul D , James, Nicola C , Jansen van Vuuren, Bettine , Whitfield, Alan K , Teske, Peter R
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445101 , vital:74347 , https://doi.org/10.3389/fmars.2021.756595
- Description: Temporary wetland ecosystems are common in arid and semi‐arid envi-ronments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geograph-ically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well-connected population or comprises different regional genetic groups, some of which may be rare or endangered.
- Full Text:
- Date Issued: 2022
The legacy of colonial and apartheid eras on the distribution, composition and representation of street trees in South Africa
- Shackleton, Charlie M, Gwedla, Nananmhla, Davoren, Elandrie
- Authors: Shackleton, Charlie M , Gwedla, Nananmhla , Davoren, Elandrie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433984 , vital:73017 , ISBN 9781003054672 , https://doi.org/10.4324/9781003054672
- Description: South Africa is a country of social, economic and racial contrasts and inequities, the roots of which can be traced back to the colonial and the post-colonial, racist apartheid periods. During these periods, urban black South Africans were restricted to living in specifically designated neighbourhoods apart from white citizens. These areas became characterised by institutionalised underdevelopment, insufficient infrastructure, limited opportunities and deep poverty. Despite the democratic transition in the mid-1990s, the imprints of the previous institutionalised segregation remain visible in many facets of the spatial geography of South African towns and cities. The legacies of colonialism and apartheid remain strongly expressed in street trees in terms of where they are found in the urban areas (i.e. very few in the former black neighbourhoods) and the provenance of prevalent species (mostly non-native species in older areas). Similarities to and reproduction of colonial approaches are evident in even contemporary initiatives such as the national social housing programme, the national Champion Trees inventory and the naming of streets after non-native species. This has translated into apathy or antagonism towards street trees in some regions by officials and the public.
- Full Text:
- Date Issued: 2022
- Authors: Shackleton, Charlie M , Gwedla, Nananmhla , Davoren, Elandrie
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433984 , vital:73017 , ISBN 9781003054672 , https://doi.org/10.4324/9781003054672
- Description: South Africa is a country of social, economic and racial contrasts and inequities, the roots of which can be traced back to the colonial and the post-colonial, racist apartheid periods. During these periods, urban black South Africans were restricted to living in specifically designated neighbourhoods apart from white citizens. These areas became characterised by institutionalised underdevelopment, insufficient infrastructure, limited opportunities and deep poverty. Despite the democratic transition in the mid-1990s, the imprints of the previous institutionalised segregation remain visible in many facets of the spatial geography of South African towns and cities. The legacies of colonialism and apartheid remain strongly expressed in street trees in terms of where they are found in the urban areas (i.e. very few in the former black neighbourhoods) and the provenance of prevalent species (mostly non-native species in older areas). Similarities to and reproduction of colonial approaches are evident in even contemporary initiatives such as the national social housing programme, the national Champion Trees inventory and the naming of streets after non-native species. This has translated into apathy or antagonism towards street trees in some regions by officials and the public.
- Full Text:
- Date Issued: 2022
The molecular basis of the effect of temperature on the structure and function of SARS-CoV-2 spike protein
- Khan, Faez I, Lobb, Kevin A, Lai, Dakun
- Authors: Khan, Faez I , Lobb, Kevin A , Lai, Dakun
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453223 , vital:75232 , xlink:href="https://doi.org/10.3389/fmolb.2022.794960"
- Description: The remarkable rise of the current COVID-19 pandemic to every part of the globe has raised key concerns for the current public healthcare system. The spike (S) protein of SARS-CoV-2 shows an important part in the cell membrane fusion and receptor recognition. It is a key target for vaccine production. Several researchers studied the nature of this protein under various environmental conditions. In this work, we applied molecular modeling and extensive molecular dynamics simulation approaches at 0°C (273.15 K), 20°C (293.15 K), 40°C (313.15 K), and 60°C (333.15 K) to study the detailed conformational alterations in the SARS-CoV-2 S protein. Our aim is to understand the influence of temperatures on the structure, function, and dynamics of the S protein of SARS-CoV-2. The structural deviations, and atomic and residual fluctuations were least at low (0°C) and high (60°C) temperature. Even the internal residues of the SARS-CoV-2 S protein are not accessible to solvent at high temperature. Furthermore, there was no unfolding of SARS-CoV-2 spike S reported at higher temperature. The most stable conformations of the SARS-CoV-2 S protein were reported at 20°C, but the free energy minimum region of the SARS-CoV-2 S protein was sharper at 40°C than other temperatures. Our findings revealed that higher temperatures have little or no influence on the stability and folding of the SARS-CoV-2 S protein.
- Full Text:
- Date Issued: 2022
- Authors: Khan, Faez I , Lobb, Kevin A , Lai, Dakun
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453223 , vital:75232 , xlink:href="https://doi.org/10.3389/fmolb.2022.794960"
- Description: The remarkable rise of the current COVID-19 pandemic to every part of the globe has raised key concerns for the current public healthcare system. The spike (S) protein of SARS-CoV-2 shows an important part in the cell membrane fusion and receptor recognition. It is a key target for vaccine production. Several researchers studied the nature of this protein under various environmental conditions. In this work, we applied molecular modeling and extensive molecular dynamics simulation approaches at 0°C (273.15 K), 20°C (293.15 K), 40°C (313.15 K), and 60°C (333.15 K) to study the detailed conformational alterations in the SARS-CoV-2 S protein. Our aim is to understand the influence of temperatures on the structure, function, and dynamics of the S protein of SARS-CoV-2. The structural deviations, and atomic and residual fluctuations were least at low (0°C) and high (60°C) temperature. Even the internal residues of the SARS-CoV-2 S protein are not accessible to solvent at high temperature. Furthermore, there was no unfolding of SARS-CoV-2 spike S reported at higher temperature. The most stable conformations of the SARS-CoV-2 S protein were reported at 20°C, but the free energy minimum region of the SARS-CoV-2 S protein was sharper at 40°C than other temperatures. Our findings revealed that higher temperatures have little or no influence on the stability and folding of the SARS-CoV-2 S protein.
- Full Text:
- Date Issued: 2022
The nexus between petroleum energy security and South Africa’s foreign policy
- Authors: Seshibedi S S
- Date: 2022
- Subjects: Petroleum industry and trade -- Government policy , Energy industries , Petroleum law and legislation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27165 , vital:66325
- Description: This study sets out to explore the nexus between South Africa’s petroleum energy security and its foreign policy. The specific objectives of the research include: to find out the state of South Africa’s oil energy security, the extent to which oil is a consideration in the development of the country’s foreign policy and the extent to which its foreign policy is framed to favour oil exporting states. Qualitative research methodology is applied in this study with the Realism as the theoretical framework. The study found out that the state of South Africa’s oil energy security, which compels the country to rely on foreign oil, provides grounds for foreign policy intervention, with discernible espousal of relations with oil exporting states that is different to those that do not produce oil. The study also found that oil is a consideration in the development of South Africa’s foreign policy, as the country’s policy strategy towards oil exporting states is to build relations of bilateral nature, through diplomatic instruments, among others. South Africa’s regional politics makes discernible the fact that South Africa prefers a policy of multilateralism to manage its relations with SADC and SACU members who are not oil exporting, while evidence showed that bilateral relations are preferred towards oil exporting states. The study recommends amongst others, that South Africa’s over-reliance on foreign oil can be mitigated by taking the lead in transitioning to renewable energy. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022
- Authors: Seshibedi S S
- Date: 2022
- Subjects: Petroleum industry and trade -- Government policy , Energy industries , Petroleum law and legislation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27165 , vital:66325
- Description: This study sets out to explore the nexus between South Africa’s petroleum energy security and its foreign policy. The specific objectives of the research include: to find out the state of South Africa’s oil energy security, the extent to which oil is a consideration in the development of the country’s foreign policy and the extent to which its foreign policy is framed to favour oil exporting states. Qualitative research methodology is applied in this study with the Realism as the theoretical framework. The study found out that the state of South Africa’s oil energy security, which compels the country to rely on foreign oil, provides grounds for foreign policy intervention, with discernible espousal of relations with oil exporting states that is different to those that do not produce oil. The study also found that oil is a consideration in the development of South Africa’s foreign policy, as the country’s policy strategy towards oil exporting states is to build relations of bilateral nature, through diplomatic instruments, among others. South Africa’s regional politics makes discernible the fact that South Africa prefers a policy of multilateralism to manage its relations with SADC and SACU members who are not oil exporting, while evidence showed that bilateral relations are preferred towards oil exporting states. The study recommends amongst others, that South Africa’s over-reliance on foreign oil can be mitigated by taking the lead in transitioning to renewable energy. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022
The Okavango Delta Peatlands
- Ellery, William N, Ellery, Karen S
- Authors: Ellery, William N , Ellery, Karen S
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434557 , vital:73077 , ISBN 978-3-030-86101-8 , https://doi.org/10.1007/978-3-030-86102-5_3
- Description: The presence of a large (approximately 2000 km2) peatland in a semi-arid climatic setting such as the Kalahari is unusual. Peat forms in permanently flooded areas in the Okavango Delta primarily due to the perennial input of large volumes of water from a distant catchment in the highlands of Angola, into a valley formed by rifting. Peat deposits form in three distinct settings in the Okavango: backswamp settings where open water is converted into homogeneous emergent peatlands, lake and channel margins where the peatland is patchy, and the inlets to lakes that connect to the primary distributary channel, which presently is the Okavango-Nqoga-Maunachira River system. An unusual feature of peat formation in backswamp areas, as well as in lake and channel margin settings, is that frequently mats of fine organic detritus on the bed rise to the water surface and are colonised by emergent plants.
- Full Text:
- Date Issued: 2022
- Authors: Ellery, William N , Ellery, Karen S
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434557 , vital:73077 , ISBN 978-3-030-86101-8 , https://doi.org/10.1007/978-3-030-86102-5_3
- Description: The presence of a large (approximately 2000 km2) peatland in a semi-arid climatic setting such as the Kalahari is unusual. Peat forms in permanently flooded areas in the Okavango Delta primarily due to the perennial input of large volumes of water from a distant catchment in the highlands of Angola, into a valley formed by rifting. Peat deposits form in three distinct settings in the Okavango: backswamp settings where open water is converted into homogeneous emergent peatlands, lake and channel margins where the peatland is patchy, and the inlets to lakes that connect to the primary distributary channel, which presently is the Okavango-Nqoga-Maunachira River system. An unusual feature of peat formation in backswamp areas, as well as in lake and channel margin settings, is that frequently mats of fine organic detritus on the bed rise to the water surface and are colonised by emergent plants.
- Full Text:
- Date Issued: 2022
The photocatalytic properties of zinc phthalocyanines supported on hematite nanofibers for use against methyl orange and Staphylococcus aureus
- Mapukata, Sivuyisiwe, Britton, Jonathan, Nwahara, Nnamdi, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Britton, Jonathan , Nwahara, Nnamdi , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230184 , vital:49751 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113637"
- Description: Heterogeneous photocatalysis is a promising approach for environmental remediation from contaminants including microorganisms and organic pollutants. In this work, hematite nanofibers are fabricated and modified with a novel monosubstituted Pc (4) as well as an asymmetrical tetrasubstituted Pc (5) with the aim of creating hybrid photocatalysts. The photocatalytic activities of the unmodified and phthalocyanine modified hematite nanofibers were compared based on their efficiencies in the photoinactivation of S. aureus and photooxidation of methyl orange. For both applications, the hybrid nanofibers were found to be more efficient photocatalysts than the unmodified hematite nanofibers. Comparison of the modified nanofibers (4-Fe2O3 and 5-Fe2O3) showed that they have comparable antibacterial activity while the 5-Fe2O3 nanofibers are the best for the photooxidation of methyl orange. The singlet oxygen generation efficiency, high activity, versatility, regenerability and thus reusability of the fabricated hybrid nanofibers makes them ideal candidates for real life water treatment studies.
- Full Text:
- Date Issued: 2022
- Authors: Mapukata, Sivuyisiwe , Britton, Jonathan , Nwahara, Nnamdi , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230184 , vital:49751 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113637"
- Description: Heterogeneous photocatalysis is a promising approach for environmental remediation from contaminants including microorganisms and organic pollutants. In this work, hematite nanofibers are fabricated and modified with a novel monosubstituted Pc (4) as well as an asymmetrical tetrasubstituted Pc (5) with the aim of creating hybrid photocatalysts. The photocatalytic activities of the unmodified and phthalocyanine modified hematite nanofibers were compared based on their efficiencies in the photoinactivation of S. aureus and photooxidation of methyl orange. For both applications, the hybrid nanofibers were found to be more efficient photocatalysts than the unmodified hematite nanofibers. Comparison of the modified nanofibers (4-Fe2O3 and 5-Fe2O3) showed that they have comparable antibacterial activity while the 5-Fe2O3 nanofibers are the best for the photooxidation of methyl orange. The singlet oxygen generation efficiency, high activity, versatility, regenerability and thus reusability of the fabricated hybrid nanofibers makes them ideal candidates for real life water treatment studies.
- Full Text:
- Date Issued: 2022
The prevalence, composition and distribution of forageable plant species in different urban spaces in two medium-sized towns in South Africa
- Garekae, Hesekia, Shackleton, Charlie M, Tsheboeng, Gaolathe
- Authors: Garekae, Hesekia , Shackleton, Charlie M , Tsheboeng, Gaolathe
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401300 , vital:69724 , xlink:href="https://doi.org/10.1016/j.gecco.2021.e01972"
- Description: Globally, the importance of urban vegetation in the quality and maintenance of life in urban areas is increasingly recognized. As the basis of urban green infrastructure, urban vegetation provides a diversity of ecosystem services, including provisioning services. However, there is limited understanding of the potential of urban vegetation as a supply of forageable resources within urban landscapes. This study examined the prevalence and distribution of forageable plant species across different spaces in the towns of Potchefstroom and Thabazimbi, South Africa. A multi-stage sampling technique was employed for selecting study sites, with a total of 136 plots sampled. In total, 88 plant species (foraged and forageable) were encountered across the sample plots, with almost three-quarters (70%) being indigenous to South Africa. Most of the species had multiple uses, with medicine, food and firewood being the most common uses, in order of frequency. Species cover and richness significantly differed across the urban spaces, being markedly higher in protected areas as compared to other spaces. Moreover, five plant communities were identified, resembling various species uses. Overall, the findings show that the fragmented urban spaces are endowed with a diversity of forageable plant species, with many valuable to particular sectors of urban society, such as foragers. Moreover, the notable number of forageable plant species encountered across the different spaces demonstrates the potential of urban green infrastructure as a supply of provisioning and cultural ecosystem services. This provides the basis for the selection of a diversity of species in urban greening programs for enhancing liveability and overall well-being in urban areas.
- Full Text:
- Date Issued: 2022
- Authors: Garekae, Hesekia , Shackleton, Charlie M , Tsheboeng, Gaolathe
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401300 , vital:69724 , xlink:href="https://doi.org/10.1016/j.gecco.2021.e01972"
- Description: Globally, the importance of urban vegetation in the quality and maintenance of life in urban areas is increasingly recognized. As the basis of urban green infrastructure, urban vegetation provides a diversity of ecosystem services, including provisioning services. However, there is limited understanding of the potential of urban vegetation as a supply of forageable resources within urban landscapes. This study examined the prevalence and distribution of forageable plant species across different spaces in the towns of Potchefstroom and Thabazimbi, South Africa. A multi-stage sampling technique was employed for selecting study sites, with a total of 136 plots sampled. In total, 88 plant species (foraged and forageable) were encountered across the sample plots, with almost three-quarters (70%) being indigenous to South Africa. Most of the species had multiple uses, with medicine, food and firewood being the most common uses, in order of frequency. Species cover and richness significantly differed across the urban spaces, being markedly higher in protected areas as compared to other spaces. Moreover, five plant communities were identified, resembling various species uses. Overall, the findings show that the fragmented urban spaces are endowed with a diversity of forageable plant species, with many valuable to particular sectors of urban society, such as foragers. Moreover, the notable number of forageable plant species encountered across the different spaces demonstrates the potential of urban green infrastructure as a supply of provisioning and cultural ecosystem services. This provides the basis for the selection of a diversity of species in urban greening programs for enhancing liveability and overall well-being in urban areas.
- Full Text:
- Date Issued: 2022
The synergistic effects of coupling Au nanoparticles with an alkynyl Co (II) phthalocyanine on the detection of prostate specific antigen
- Nxele, Siphesihle Robin, Nkhahle, Reitumetse, Nyokong, Tebello
- Authors: Nxele, Siphesihle Robin , Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230232 , vital:49756 , xlink:href="https://doi.org/10.1016/j.talanta.2021.122948"
- Description: Prostate specific antigen (PSA) aptasensors are fabricated using a novel asymmetrically substituted Co phthalocyanine (CoPc), gold nanoparticles (AuNPs) and PSA-specific antigen. The fabricated aptasensors are: GCE-AuNPs-Aptamer, GCE@CoPc-Aptamer and GCE-AuNPs@CoPc-Aptamer (GCE = glassy carbon electrode). The fabricated sensors are characterized at each modification step to monitor the changes occurring at the sensor surface. Concentration studies were carried out using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) to determine detection limits. All the fabricated aptasensors were found to be highly specific and selective but the GCE-AuNPs@CoPc-Aptamer nanoconjugate performed the best. The aptasensors were also tested in spiked serum samples and detection limits, as well as % recoveries were determined. The results obtained showed that the GCE-AuNPs@CoPc-Aptamer has the potential to be used for clinical studies as the results agree with those obtained for detection of PSA in buffer.
- Full Text:
- Date Issued: 2022
- Authors: Nxele, Siphesihle Robin , Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230232 , vital:49756 , xlink:href="https://doi.org/10.1016/j.talanta.2021.122948"
- Description: Prostate specific antigen (PSA) aptasensors are fabricated using a novel asymmetrically substituted Co phthalocyanine (CoPc), gold nanoparticles (AuNPs) and PSA-specific antigen. The fabricated aptasensors are: GCE-AuNPs-Aptamer, GCE@CoPc-Aptamer and GCE-AuNPs@CoPc-Aptamer (GCE = glassy carbon electrode). The fabricated sensors are characterized at each modification step to monitor the changes occurring at the sensor surface. Concentration studies were carried out using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) to determine detection limits. All the fabricated aptasensors were found to be highly specific and selective but the GCE-AuNPs@CoPc-Aptamer nanoconjugate performed the best. The aptasensors were also tested in spiked serum samples and detection limits, as well as % recoveries were determined. The results obtained showed that the GCE-AuNPs@CoPc-Aptamer has the potential to be used for clinical studies as the results agree with those obtained for detection of PSA in buffer.
- Full Text:
- Date Issued: 2022
The thermal physiology of Lysathia sp.(Coleoptera: Chrysomelidae), a biocontrol agent of parrot’s feather in South Africa, supports its success
- Goddard, Matthew, Owen, Candice A, Grant, Martin D, Coetzee, Julie A
- Authors: Goddard, Matthew , Owen, Candice A , Grant, Martin D , Coetzee, Julie A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417806 , vital:71487 , xlink:href="https://doi.org/10.1080/09583157.2022.2054949"
- Description: The establishment success of biocontrol agents originating from tropical regions is often limited by climate when introduced in temperate regions. However, the flea beetle, Lysathia sp. (Coleoptera: Chrysomelidae), a biocontrol agent of Myriophyllum aquaticum (Vell.) Verdc. (Haloragaceae) in South Africa, is an effective agent in regions where other biocontrol agents of tropical aquatic weeds have failed due to winter-induced mortality. The development (degree-day model) and thermal tolerance (critical thermal minimum/maximum [CTmin/max] and lower/upper lethal limits [LLT/ULT50]) of Lysathia sp. were investigated to explain this success. The model predicted that Lysathia sp. could complete 6 to 12 generations per year in the colder regions of the country. The lower threshold for development (t0) was 13.0 °C and thermal constant (K) was 222.4 days, which is considerably lower than the K values of other biocontrol agents of aquatic weeds in South Africa. This suggests that above the temperature threshold, Lysathia sp. can develop faster than those other species and complete multiple life cycles in the cooler winter months, allowing for rapid population growth and thus improving M. aquaticum control. Furthermore, the CTmin of Lysathia sp. was 2.3 ± 0.2 °C and the CTmax was 49.0 ± 0.5 °C. The LLT50 was calculated as ∼ −7.0 °C and the ULT50 as ∼ 43.0 °C. These wide tolerance ranges and survival below freezing show why Lysathia sp. has established at cool sites and suggest that it may be a suitable agent for other cold countries invaded by M. aquaticum.
- Full Text:
- Date Issued: 2022
- Authors: Goddard, Matthew , Owen, Candice A , Grant, Martin D , Coetzee, Julie A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417806 , vital:71487 , xlink:href="https://doi.org/10.1080/09583157.2022.2054949"
- Description: The establishment success of biocontrol agents originating from tropical regions is often limited by climate when introduced in temperate regions. However, the flea beetle, Lysathia sp. (Coleoptera: Chrysomelidae), a biocontrol agent of Myriophyllum aquaticum (Vell.) Verdc. (Haloragaceae) in South Africa, is an effective agent in regions where other biocontrol agents of tropical aquatic weeds have failed due to winter-induced mortality. The development (degree-day model) and thermal tolerance (critical thermal minimum/maximum [CTmin/max] and lower/upper lethal limits [LLT/ULT50]) of Lysathia sp. were investigated to explain this success. The model predicted that Lysathia sp. could complete 6 to 12 generations per year in the colder regions of the country. The lower threshold for development (t0) was 13.0 °C and thermal constant (K) was 222.4 days, which is considerably lower than the K values of other biocontrol agents of aquatic weeds in South Africa. This suggests that above the temperature threshold, Lysathia sp. can develop faster than those other species and complete multiple life cycles in the cooler winter months, allowing for rapid population growth and thus improving M. aquaticum control. Furthermore, the CTmin of Lysathia sp. was 2.3 ± 0.2 °C and the CTmax was 49.0 ± 0.5 °C. The LLT50 was calculated as ∼ −7.0 °C and the ULT50 as ∼ 43.0 °C. These wide tolerance ranges and survival below freezing show why Lysathia sp. has established at cool sites and suggest that it may be a suitable agent for other cold countries invaded by M. aquaticum.
- Full Text:
- Date Issued: 2022